initial commit
Diff
.gitignore | 5 +++++
404.html | 25 +++++++++++++++++++++++++
Gemfile | 30 ++++++++++++++++++++++++++++++
Gemfile.lock | 80 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
README.md | 3 +++
_config.yml | 34 ++++++++++++++++++++++++++++++++++
about.markdown | 18 ++++++++++++++++++
elementary.gemspec | 14 ++++++++++++++
favicon.ico | 0
feed.xml | 30 ++++++++++++++++++++++++++++++
index.html | 33 +++++++++++++++++++++++++++++++++
robots.txt | 3 +++
tags.html | 28 ++++++++++++++++++++++++++++
_chem12/2020-01-10-news-article.md | 18 ++++++++++++++++++
_chem12/Alkaline_Nonsense.md | 109 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
_chem12/Alkaline_Water_Nonsense.md | 111 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
_chem12/Cadmium_Issues.md | 115 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
_chem12/Can_coffee_explode_in_the_microwave_oven.md | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++
_chem12/Cleaning_the_air_with_jeans.md | 96 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
_chem12/DEET_Me_Up.md | 75 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
_chem12/Does_the_Magnetic_Laundry_System_work.md | 72 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
_chem12/Hazard_and_risk.md | 102 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
_chem12/If_you_were_using.md | 45 +++++++++++++++++++++++++++++++++++++++++++++
_chem12/Love_it_or_Hate_it.md | 110 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
_chem12/National_Bunsen_Burner_Day.md | 68 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
_chem12/Should_one_worry_about_reboiling_water_for_coffee_or_tea.md | 32 ++++++++++++++++++++++++++++++++
_chem12/Sugar_research_left_a_bitter_taste.md | 120 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
_chem12/The_U.S._Toxic_Substances_Control_Act_TSCA.md | 63 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
_chem12/Tires_and_ice_dont_make_for_a_good_mix.md | 54 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
_chem12/What_is_natamycin.md | 65 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
_chem12/Why_Does_Copper_Oxidize_and_Turn_Green.md | 186 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
_chem12/Why_does_coffee_heated_up_in_the_microwave_foam_up_when_sugar_is_added.md | 41 +++++++++++++++++++++++++++++++++++++++++
_includes/featured.html | 8 ++++++++
_includes/head.html | 36 ++++++++++++++++++++++++++++++++++++
_includes/nav.html | 4 ++++
_layouts/default.html | 14 ++++++++++++++
_layouts/page.html | 17 +++++++++++++++++
_layouts/post.html | 104 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
_sass/common.scss | 323 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
_sass/constants.scss | 4 ++++
_sass/darkmode.scss | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++
_sass/main.scss | 5 +++++
_sass/syntax-highlighter.scss | 70 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
_sass/typography.scss | 13 +++++++++++++
assets/main.js | 74 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
assets/main.scss | 4 ++++
tmp/dark-mode.gif | 0
tmp/perf-2.jpg | 0
tmp/scroll-progress.gif | 0
assets/fonts/open-sans-v17-latin-regular.woff | 0
assets/fonts/open-sans-v17-latin-regular.woff2 | 0
51 files changed, 2561 insertions(+)
@@ -1,0 +1,5 @@
_site
.sass-cache
.jekyll-cache
.jekyll-metadata
vendor
@@ -1,0 +1,25 @@
---
permalink: /404.html
layout: default
---
<style type="text/css" media="screen">
.container {
margin: 10px auto;
max-width: 600px;
text-align: center;
}
h1 {
margin: 30px 0;
font-size: 4em;
line-height: 1;
letter-spacing: -1px;
}
</style>
<div class="container">
<h1>404</h1>
<p><strong>Page not found :(</strong></p>
<p>The requested page could not be found.</p>
</div>
@@ -1,0 +1,30 @@
source "https://rubygems.org"
gem "jekyll", "~> 4.2.0"
gem "minima", "~> 2.5"
group :jekyll_plugins do
gem "jekyll-feed", "~> 0.12"
end
platforms :mingw, :x64_mingw, :mswin, :jruby do
gem "tzinfo", "~> 1.2"
gem "tzinfo-data"
end
gem "wdm", "~> 0.1.1", :platforms => [:mingw, :x64_mingw, :mswin]
@@ -1,0 +1,80 @@
GEM
remote: https://rubygems.org/
specs:
addressable (2.7.0)
public_suffix (>= 2.0.2, < 5.0)
colorator (1.1.0)
concurrent-ruby (1.1.8)
em-websocket (0.5.2)
eventmachine (>= 0.12.9)
http_parser.rb (~> 0.6.0)
eventmachine (1.2.7)
ffi (1.15.0)
forwardable-extended (2.6.0)
http_parser.rb (0.6.0)
i18n (1.8.10)
concurrent-ruby (~> 1.0)
jekyll (4.2.0)
addressable (~> 2.4)
colorator (~> 1.0)
em-websocket (~> 0.5)
i18n (~> 1.0)
jekyll-sass-converter (~> 2.0)
jekyll-watch (~> 2.0)
kramdown (~> 2.3)
kramdown-parser-gfm (~> 1.0)
liquid (~> 4.0)
mercenary (~> 0.4.0)
pathutil (~> 0.9)
rouge (~> 3.0)
safe_yaml (~> 1.0)
terminal-table (~> 2.0)
jekyll-feed (0.15.1)
jekyll (>= 3.7, < 5.0)
jekyll-sass-converter (2.1.0)
sassc (> 2.0.1, < 3.0)
jekyll-seo-tag (2.7.1)
jekyll (>= 3.8, < 5.0)
jekyll-watch (2.2.1)
listen (~> 3.0)
kramdown (2.3.1)
rexml
kramdown-parser-gfm (1.1.0)
kramdown (~> 2.0)
liquid (4.0.3)
listen (3.5.1)
rb-fsevent (~> 0.10, >= 0.10.3)
rb-inotify (~> 0.9, >= 0.9.10)
mercenary (0.4.0)
minima (2.5.1)
jekyll (>= 3.5, < 5.0)
jekyll-feed (~> 0.9)
jekyll-seo-tag (~> 2.1)
pathutil (0.16.2)
forwardable-extended (~> 2.6)
public_suffix (4.0.6)
rb-fsevent (0.10.4)
rb-inotify (0.10.1)
ffi (~> 1.0)
rexml (3.2.5)
rouge (3.26.0)
safe_yaml (1.0.5)
sassc (2.4.0)
ffi (~> 1.9)
terminal-table (2.0.0)
unicode-display_width (~> 1.1, >= 1.1.1)
unicode-display_width (1.7.0)
PLATFORMS
ruby
DEPENDENCIES
jekyll (~> 4.2.0)
jekyll-feed (~> 0.12)
minima (~> 2.5)
tzinfo (~> 1.2)
tzinfo-data
wdm (~> 0.1.1)
BUNDLED WITH
2.1.4
@@ -1,0 +1,3 @@
# DebReader
This is a quick tool I made to get course readings done in high school. Hopefully it can be used by subsequent students.
@@ -1,0 +1,34 @@
title : The Deb-Reader
name: 'The DebReader™'
description: 'Simple, light weight, responsive jekyll theme for hackers'
markdown: kramdown
highlighter: rouge
javascript_enabled: false
featured_posts_title: Unrelated
featured_posts:
- url: '#'
title: 'Featured post #1'
- url: '#'
title: 'Featured post #2'
- url: '#'
title: 'Featured post #3'
collections:
chem12:
title: Chemistry 12
default_open: false
output: true
defaults:
- scope:
type: posts
values:
title: Essays
permalink: /post/:title
- scope:
type: news
values:
title: News
permalink: /news/:title
@@ -1,0 +1,18 @@
---
layout: page
title: About
permalink: /about/
---
This is the base Jekyll theme. You can find out more info about customizing your Jekyll theme, as well as basic Jekyll usage documentation at [jekyllrb.com](https://jekyllrb.com/)
You can find the source code for Minima at GitHub:
[jekyll][jekyll-organization] /
[minima](https://github.com/jekyll/minima)
You can find the source code for Jekyll at GitHub:
[jekyll][jekyll-organization] /
[jekyll](https://github.com/jekyll/jekyll)
[jekyll-organization]: https://github.com/jekyll
@@ -1,0 +1,14 @@
Gem::Specification.new do |spec|
spec.name = "elementary"
spec.version = "0.1.0"
spec.authors = ["Abhishek Nagekar"]
spec.email = ["abhishek@nagekar.com"]
spec.summary = %q{Minimalistic Jekyll Theme}
spec.homepage = "https://elementary-jekyll.github.io"
spec.license = "MIT"
spec.add_runtime_dependency "jekyll", "~> 4.0"
end
Binary files /dev/null and a/favicon.ico differ
@@ -1,0 +1,30 @@
---
layout: null
---
<?xml version="1.0" encoding="UTF-8"?>
<rss version="2.0" xmlns:atom="http://www.w3.org/2005/Atom">
<channel>
<title>{{ site.title | xml_escape }}</title>
<description>{{ site.description | xml_escape }}</description>
<link>{{ site.url }}{{ site.baseurl }}/</link>
<atom:link href="{{ "/feed.xml" | prepend: site.baseurl | prepend: site.url }}" rel="self" type="application/rss+xml"/>
<pubDate>{{ site.time | date_to_rfc822 }}</pubDate>
<lastBuildDate>{{ site.time | date_to_rfc822 }}</lastBuildDate>
<generator>Jekyll v{{ jekyll.version }}</generator>
{% for post in site.posts limit:10 %}
<item>
<title>{{ post.title | xml_escape }}</title>
<description>{{ post.content | xml_escape }}</description>
<pubDate>{{ post.date | date_to_rfc822 }}</pubDate>
<link>{{ post.url | prepend: site.baseurl | prepend: site.url }}</link>
<guid isPermaLink="true">{{ post.url | prepend: site.baseurl | prepend: site.url }}</guid>
{% for tag in post.tags %}
<category>{{ tag | xml_escape }}</category>
{% endfor %}
{% for cat in post.categories %}
<category>{{ cat | xml_escape }}</category>
{% endfor %}
</item>
{% endfor %}
</channel>
</rss>
@@ -1,0 +1,33 @@
---
layout: default
cover: false
---
<header>
<h1>{{ site.name }}</h1>
</header>
<hr class="stylish"/>
<main class="home-main">
{% for collection in site.collections %}
{% if collection.docs.size > 0 %}
<section id="posts">
<details {% if collection.default_open %}open{% endif %}>
<summary>
<h3 class="home-page-heading">{{ collection.title }}</h3>
</summary>
<div class="parent">
{% for post in collection.docs %}
<div class="post-wrapper">
<a class="post-link" href="{{ post.url }}">
{{ post.title }}
</a>
</div>
{% endfor %}
</div>
</details>
</section>
{% endif %}
{% endfor %}
</main>
@@ -1,0 +1,3 @@
User-agent: *
Disallow: /
Disallow: /
@@ -1,0 +1,28 @@
---
layout: page
title: Tags
---
{% assign alldocs = site.documents %}
{% assign alltags = alldocs | map: 'tags' | join: ',' | split: ',' | group_by: tag %}
<p>
Articles on similar topics are grouped together by tags. Click on any tag to find all the articles 'tagged' with that tag.
</p>
<ul class="tag-box">
{% for tag in alltags %}
<li><a href="#{{ tag.name | slugify }}">{{ tag.name }} <span>{{ tag.size }}</span></a></li>
{% endfor %}
{% assign tags_list = nil %}
</ul>
{% for tag in alltags %}
<h2 class="nice-title" id="{{ tag.name }}">{{ tag.name }}</h2>
<ul>
{%- for document in alldocs -%}
{% if document.tags contains tag.name %}
<li><a href="{{ document.url }}">{{ document.title }}</a></li>
{% endif %}
{% endfor %}
</ul>
{% endfor %}
@@ -1,0 +1,18 @@
---
layout: post
title: Example Of A News Article
author: Joe Schwarcz
source: McGill Blogs
---
Lorem ipsum dolor sit amet, consectetur adipiscing elit. Donec pellentesque purus eu odio tempus hendrerit. Ut vel pellentesque nulla, quis varius orci. Nunc dapibus vel metus sit amet dignissim. Aenean erat purus, porta id arcu in, vehicula semper sem. Suspendisse quis sollicitudin neque. Aenean vitae massa nec ante blandit tincidunt. Ut ornare faucibus nulla sit amet mattis. Donec sollicitudin pharetra feugiat. Curabitur tempus congue pharetra. Proin ultrices, purus et tristique euismod, mauris augue posuere felis, in feugiat diam justo a diam. Vestibulum sed vehicula ante. Curabitur pharetra pellentesque enim, eget rhoncus nunc cursus non.
Integer sodales pretium dolor et dapibus. Pellentesque cursus velit lectus, at scelerisque ligula facilisis tristique. Vivamus ac nunc elit. Phasellus fringilla porta est, ut rutrum elit fringilla quis. Fusce convallis nulla at fringilla fermentum. Etiam vel erat ut elit scelerisque congue quis at magna. Phasellus cursus ultrices neque, id efficitur mi. Phasellus eget augue consequat, porta augue sit amet, luctus massa. Fusce quis ornare lacus, sed sollicitudin dolor. Sed hendrerit arcu quis auctor eleifend.
Nam eget volutpat tellus. Suspendisse posuere bibendum dolor, eu vulputate justo egestas eget. Duis eget neque tincidunt, rutrum massa ac, tempor massa. Mauris dignissim scelerisque nulla ac porttitor. Sed sit amet neque eros. Sed ullamcorper ac tellus a tempor. In hac habitasse platea dictumst. Cras elementum fermentum lorem vitae finibus. Maecenas interdum eros eget neque iaculis euismod. Sed nec enim pulvinar, dignissim lacus vitae, laoreet ipsum. Nulla mollis quam at risus facilisis laoreet. Sed justo urna, lobortis in lobortis ac, convallis quis est. In consequat, sapien eget tristique pharetra, velit neque vulputate eros, vel molestie orci nisi semper eros.
Mauris ut congue elit. Proin posuere enim ipsum, sed iaculis libero vehicula at. Morbi luctus lacinia commodo. Maecenas vitae suscipit nisi. Pellentesque tempor mauris lacus, id lobortis tortor finibus ac. Aliquam et placerat est. Nunc semper lacus turpis, quis auctor nulla dictum vitae. Vivamus sed ultrices quam. Quisque pharetra urna sed nibh varius feugiat. Mauris et est quis eros consequat accumsan. Cras tellus purus, pulvinar vel maximus nec, convallis ac est. Donec sit amet faucibus tortor, vel egestas quam. Proin et semper lorem. Nulla dignissim auctor diam et dictum. Cras venenatis quis turpis ac suscipit. Quisque blandit tincidunt magna vel posuere.
In at malesuada ligula, condimentum accumsan libero. Ut mollis nulla sed maximus venenatis. Aenean nulla justo, tristique id pharetra nec, tincidunt ac nisl. Donec enim enim, lobortis a mi ac, sagittis lobortis dui. Aliquam erat volutpat. Integer non maximus augue, eu molestie felis. Phasellus a ligula nisl. Phasellus rhoncus, mauris eu lobortis fringilla, mauris augue sagittis urna, id hendrerit velit felis ac tellus. Aliquam id suscipit nisi, elementum vehicula nunc.
@@ -1,0 +1,109 @@
---
layout: post
title: Alkaline Nonsense
author: Joe Schwarcz
source: McGill Blogs
---
HYPERLINK "http://blogs.mcgill.ca/oss/2016/09/19/alkaline-nonsense/"
Alkaline Nonsense
It is so seductively simple. If you want to avoid cancer, just make
sure your body is “alkaline!” Here is the rationale. When a cell
becomes cancerous it reduces its use of oxygen and cranks up its
production of acids. These conditions then allow such cells to
multiply quickly. To counter this, you have to ensure that cells get
an adequate supply of oxygen and that the acids produced are
neutralized. How? By introducing sources of oxygen such as hydrogen
peroxide or ozone into the body and consuming “alkaline” foods. If
cancer has already taken a foothold, then it may be necessary to dose up
on cesium, the “most alkaline nutritional mineral.” So simple, and
so wrong!
As so often happens, promoters of nonsensical therapies seize a few
filaments of scientific fact and weave these into a tangled web that
ensnares the desperate and the scientifically confused. In this case,
it all starts with the work of German physician Otto Warburg who
received the 1931 Nobel Prize in medicine for his work on cellular
metabolism. Warburg showed that that the growth of malignant cells
requires markedly smaller amounts of oxygen than that of normal cells
and that their metabolism follows an “anaerobic” pathway leading to
the production of lactic acid. This notion lay dormant until the
1980’s when Dr. Keith Brewer, a physicist with no medical training,
used it to support his perplexing theory of how potassium and calcium
control the transport of glucose and oxygen into cells, and how
irritation of the cell’s membrane interferes with this transport
system. The result, Brewer maintained, is the “Warburg effect,”
which lowers the cell’s pH, reduces its oxygen supply, and causes
changes in DNA characteristic of cancer. He then went on to claim that
cesium’s chemically similarity to potassium allows it to be readily
taken up by cells, but that unlike potassium, it does not transport
glucose into cells while allowing oxygen to enter. As a result, cancer
cells are enriched in oxygen, deprived of glucose, form less lactic
acid, become more alkaline, and as a consequence, die. Sounds good,
but Brewer got the “Warburg effect” all wrong. Cancer cells do
shift to a mode of metabolism that doesn’t use oxygen, but this
happens even in the presence of oxygen!
Brewer went on to buttress his argument by claiming that cancer is
almost unknown among the Hopi Indians of Arizona, the highland Indians
of Peru and the Hunza of North Pakistan. Why? Because due to the
cesium in the soil, they have a “high pH” diet. Whether these
people actually do have a lower cancer rate is questionable, and even if
this were the case, it could not be ascribed to caesium in the diet
without further investigation. But then to take the cake (undoubtedly
cesium enriched) Brewer in 1984 published a paper with the following
claim: “Tests have been carried out on over 30 humans and in each case
the tumour masses disappeared. Also, all pains and effects associated
with cancer disappeared within 12 to 36 hours; the more chemotherapy and
morphine the patient had taken, the longer the withdrawal period.”
Not only had he discovered the cancer cure that had eluded the thousands
of PhDs and MDs working in cancer research around the world, but he also
showed that chemotherapy was actually harmful. Quite a claim!
And just where were these miraculously cured patients, and who had
treated them? Brewer refers to Dr. Hellfried Sartori (aka Prof.
Abdul-Haqq Sartori) who had accomplished this incredible feat in the
Washington D.C. area. This is the same Dr. Sartori who in July of 2006
was arrested in Thailand for fraud and practicing medicine without a
license. He was charging desperate patients were up $50,000 for
“cancer cures” which included cesium chloride injections. The good
doctor, who routinely promised that he could cure his patients of any
disease, has a rather illustrious history. Known as the notorious
“Dr. Ozone” in the U.S. , he served five years in prison in Virginia
and nine months in New York for defrauding patients with unapproved
therapies such as cesium chloride injections, coffee enemas and ozone
flushes. Needless to say, there are no records of the patients whom,
according to Brewer, Sartori cured of cancer. Australian police are
now looking into the deaths of six people who died after intravenous
injections of cesium chloride at clinics following Sartori’s protocol.
Introducing ozone or hydrogen peroxide to raise cellular oxygen levels
is a scientifically bankrupt idea, as is raising a cell’s pH with
cesium chloride. Of course, it is not the absurdity of the theory that
rules out its effectiveness, it is the lack of evidence! There are no
controlled trials showing cancer being cured with ozone or cesium. But
there is evidence that cesium chloride can cause cardiac arrhythmia and
death. Granted, it is unlikely that this can happen from the oral
doses being promoted by numerous alternative practitioners aimed at
raising the body’s pH, but the idea that cesium chloride can
neutralize acids in cells is sheer nonsense.
Yes, cesium is an “alkali” metal. Dropping a piece of cesium metal
into water does indeed produce an alkaline solution (and an
explosion). But cesium chloride is not the same as cesium metal, it is
a neutral salt. In any case, the blood’s pH cannot be altered by
cesium chloride ingestion, or indeed with the ingestion of any food.
It is a marvelously buffered system, meaning that it resists any change
in acidity. It doesn’t matter what we eat or drink, our blood
contains substances that can act as acids or bases to maintain our blood
pH at 7.4. The only body fluid that responds to diet in terms of pH is
the urine. Breads, cereals, eggs, fish, meat and poultry can make the
urine more acidic while most, but not all, fruits and vegetables make
the urine more alkaline. A diet high in fruits and vegetables and low
in meat can indeed reduce the risk of cancer, but this has absolutely
nothing to do with changing the pH of cancer cells. The idea of an
“alkaline” diet to prevent or treat cancer may sound seductively
simple, but in reality it is just simple minded.
Joe Schwarcz PhD – Sept 19th/2016
@@ -1,0 +1,111 @@
---
layout: post
title: Alkaline Water Nonsense
author: Joe Schwarcz
source: McGill Blogs
---
HYPERLINK
"http://blogs.mcgill.ca/oss/2014/03/20/alkaline-water-nonsense/"
Alkaline Water Nonsense
It is not often that I’m left speechless. But sometimes you run
into a situation where words just fail you. Absurd, ridiculous,
ludicrous, preposterous, comical, and farcical come to mind, but they
still don’t quite seem to capture the extent of the mind-numbing
nonsense. And what nonsense is that? “Ionized Alkaline Water!”
People, seduced by the outlandish promotional drivel, are spending
thousands of dollars for a device that produces this liquid malarkey.
Some promoters just blather mindlessly about increasing energy, reducing
weight, reversing aging, boosting immunity, controlling blood pressure,
cleansing the colon or eliminating body odour. More disturbing are the
ones who speak of preventing cancer and increasing life expectancy.
And how is alkalized water supposed to accomplish these miracles?
Well, you see, “all electrons in water either spin to the left or the
right and high speed of the left spin of electrons is considered to
substantiate that the water is vital and alive. Only ionized water has
this quality.” Uh huh. There’s more. “Ionized water oxygenates
the body via an increase in the oxygen-hydrogen angle. All other water
is void of this benefit.” Yeah, sure. “Ionized water has
positive polarity. Almost all other waters are negative in their
polarity. Only positive polarity can efficiently flush out toxins and
poisons in the body at the cellular level.” There’s still more.
The amazing water ionizer produces “smaller water molecule clusters
which enables every nook and cranny of your body to be
super-hydrated” Makes you head swim.
All this rubbish does have an effect. It makes anyone with a chemistry
background want to tear their hair out. Of course, the promoters of
ionized alkalized water have an answer to that too. They claim the
water has a calming effect and can even grow hair. Not only is there
not an iota of scientific evidence for any of the claims, the notion of
“ionized alkaline water” having any therapeutic effect is beyond
absurd. In fact, the term “ionized alkaline water” is
scientifically meaningless.
What then does an “ionizer” actually do? The same thing that high
school students do in chemistry labs when they stick a couple of
electrodes in water and pass a current between them in a classic
“electrolysis” experiment. Some of the water molecules break down,
forming hydrogen gas at the negative electrode and oxygen at the
positive electrode. Electrolysis, however, cannot be carried out with
pure water since water cannot conduct an electric current. For
electrolysis to proceed, some sort of charged species must be dissolved
in the water. Atoms, or groups of atoms that bear a charge are called
ions. Tap water contains a variety of dissolved ions such as calcium,
magnesium, sodium, bicarbonate or chloride, so it is amenable to
electrolysis.
As water molecules break down at the negative electrode to release
hydrogen gas, they leave behind negative hydroxide ions. This is what
makes a solution “alkaline.” Basically what this means is that
as electrolysis proceeds, a dilute solution of sodium hydroxide
(negative ions are always paired with positive ones) is produced around
the negative electrode and can be drawn off as “alkaline” or
“ionized” water. But you don’t need an exorbitantly expensive
device to produce a dilute sodium hydroxide solution. A couple of
pellets of drain cleaner in a liter of water will do the job. So will
a spoonful of baking soda. Of course these solutions will not produce
any medical miracles. But neither will the posh alkaline water.
What this expensive water does produce is a bevy of daft claims. Here
is the most popular one: “It is well known in the medical community
that an overly acidic body is the root of many common diseases, such as
obesity, osteoporosis, diabetes, high blood pressure and more.”
Poppycock! There is no such thing as an “acidic body.” That,
though, doesn’t stop the hucksters from treating it. How? By
neutralizing the acidity with their alkaline water. “The alkaline
water will restore your body to a healthy alkaline state,” they say.
“It counteracts the acidic food you eat and the effects of the harsh
elements in your environment in order to bring about the natural balance
your body needs. Change your water and change your life.” The only
thing you’ll change is your bank balance.
Now, even if there were such a thing as an acidic body, and even if this
signaled illness, it could not be countered by drinking alkaline
water. To “alkalize the body” one would have to alkalize the
blood. But our body maintains the pH of the blood between 7 -7.4,
which is already alkaline. If you were to alkalize it further, you
would not have to worry about illness because you would be dead.
Don’t worry, though, about alkaline water killing you. Our stomach
is strongly acidic and any base that enters is immediately
neutralized. The still acidic contents of the stomach then pass into
the intestine where they are neutralized by alkaline secretions from the
pancreas. So all of the water we drink ends up being alkaline anyway!
Another seductive claim is that alkaline ionized water is an antioxidant
and neutralizes free radicals. This is often demonstrated by immersing
an Oxidation-Reduction Potential (ORP) probe into the water and pointing
out that the needle moves into the negative millivolt region, while
ordinary water shows a positive reading. An ORP probe is useful in
determining water quality in a swimming pool, but is meaningless for
drinking water. The slightest amount of dissolved hydrogen, as you
have in alkalized water, will result in a negative reading. This has
absolutely no relevance to any effect on the body. Oil may not mix
with water, but it seems snake oil surely does.
Joe Schwarcz – March 20th/2016
@@ -1,0 +1,115 @@
---
layout: post
title: Cadmium Issues
author: Joe Schwarcz
source: McGill Blogs
---
HYPERLINK "http://blogs.mcgill.ca/oss/2016/03/01/cadmium-issues/"
Cadmium Issues
Shrek the friendly ogre delighted audiences in the 2010 movie hit
“Shrek Forever After.” But for fast food giant McDonald’s, Shrek
turned out to be a nightmare. As a cross promotional feature, the
company introduced a set of glasses decorated with images of Shrek and
other characters from the film. After millions of the glasses had been
sold, a problem cropped up that led to a large scale recall. The yellow
pigment used on the cups turned out to be cadmium sulphide, a substance
toxic even in small amounts. The concern was that the pigment might rub
off on children’s hands and end up being ingested if they then put
their hands into their mouth.
Cadmium was discovered in 1817 by Professor Friedrich Strohmeyer in
Germany while looking into a problem encountered by apothecaries who
were making calamine lotion for skin care. The process involved heating
“calamine,” a natural ore of zinc carbonate, to produce zinc oxide,
which is the active ingredient in calamine lotion. Sometimes the lotion
would end up with a yellow discolouration which Strohmeyer determined
was due to a mineral contaminant that he eventually identified as a
compound of cadmium.
It was the colour of cadmium compounds that led to their first
commercial use. Artists loved the bright yellow of cadmium sulphide and
the reds and oranges resulting from a mixture of cadmium sulphide and
cadmium selenide. Vincent van Gogh used cadmium sulphide to impart the
yellow colour to his flowers in his famous “Flowers in a Blue Vase.”
Unfortunately, with time, cadmium sulphide oxidizes to cadmium sulphate,
which is white, resulting in the original colour of the painting being
slowly altered. HYPERLINK
"http://www.artnet.com/artists/claude-monet/" \t "_blank" Claude Monet
‘s famous yellow hues were also achieved with cadmium pigments.
Cadmium paints are still used today, although they are being phased out.
Indeed, Sweden has submitted a report to the European Chemical Agency
claiming that artists rinsing their brushes in the sink are responsible
for spreading cadmium over agricultural land via sewage sludge.
Cadmium is a cumulative toxin and the World Health Organization has
suggested 70 micrograms as the maximum daily safe intake. Ingesting some
cadmium is unavoidable because it shows up in crops. How does it get
there? Sewage sludge and phosphate rock, both used as fertilizer, can
harbour cadmium. As a result, a hamburger can contain about 30
micrograms of cadmium that can be traced to the grass or hay the cow
ate, and ultimately to the soil in which the feed was grown. Coal also
contains cadmium compounds that can end up in the atmosphere from where
they find their way into soil via rain. Other cadmium compounds may also
be released from the nickel-cadmium battery industry, although modern
pollution control methods minimize such losses. Cadmium can be also be
found in significant amounts as a contaminant in zinc ores and some is
released into the environment when the ore is mined as well as when it
is smelted into zinc.
Nobody actually carried out a study to determine how much cadmium
pigment can rub off onto little hands when gripping a Shrek glass, but
it could well be less than what is found in the hamburger those hands
are clutching. Still, eliminating any avoidable source of cadmium is
desirable, especially since there is suspicion that cadmium compounds
may be carcinogenic. Cadmium can also build up in joints and the spine
causing a disease that the Japanese have named “Itai-Itai,” which
translates as “ouch-ouch,” due to the painful sounds made by victims
as cadmium accumulates.
A classic case of environmental cadmium toxicity can be traced back to
the early 1900s, although its cause was not identified until the 1960s.
It was obvious that something was going on in the vicinity of the Jinzu
River and its tributaries in China. People were getting sick, screaming
in pain and dying prematurely. Suspicion fell on the river and the
mining companies that for years and years had been disgorging their
wastes into the water. The mountains upstream were rich in minerals that
contained silver, lead, copper and zinc, and mines had been operating
there for centuries. As demand for these metals increased in the
twentieth century, more and more mining wastes found their way into the
river, including increased amounts of cadmium ores.
River water was used for irrigation of rice fields, and since rice
absorbs cadmium effectively, the metal accumulated in the food supply
and consequently in the bodies of the population. The result was
ouch-ouch disease. Although cadmium was only identified as the cause
around 1965, by the late 1940s it had become obvious that the disease
was linked to the water supply and mining companies began to store their
wastes instead of releasing them into the river. This prevented more
people from contracting cadmium poisoning, but nobody really knows how
many victims the mining operations had since they began to pollute the
Jinzu River back in the sixteenth century.
In 1966 in England a construction worker died and several others were
sickened as a result of inhaling cadmium fumes. The men were using a
welding torch to remove bolts as they were dismantling a construction
tower used in the building of a bridge. It is common practice to
electroplate steel bolts with cadmium, particularly those exposed to
water. This is especially useful when there is contact with sea water
since cadmium reacts with salt to form an impervious layer of cadmium
chloride. In this case the men inhaled the cadmium vapourized by the
heat of the welding torch and suffered an acute reaction.
Shrek glasses are not the only items aimed at children that have caused
a concern about cadmium. With lead being non-grata, cadmium has been
turning up in jewelry aimed at young girls, mostly originating in China.
If pieces are accidentally swallowed, or if the jewelry comes into
frequent contact with the mouth, enough cadmium may enter the
circulation to cause harm. Jewelry made with cadmium should to go the
way of the Shrek glasses.
Joe Schwarcz PhD – March 1/2016
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---
layout: post
title: Can coffee explode in the microwave oven
author: Joe Schwarcz
source: McGill Blogs
---
HYPERLINK
"http://blogs.mcgill.ca/oss/2016/05/06/you-asked-can-coffee-explode-in-t
he-microwave-oven/" You Asked: Can coffee explode in the microwave
oven?
A sensational sounding e-mail about “exploding coffee” has been
making the rounds. It describes the misadventures of an unfortunate soul
who heated up water for coffee in a microwave oven. When he picked up
the mug, it “exploded!”
Explode is probably too strong a term, but spurting and frothing is a
real possibility. This is due to a phenomenon known as superheating.
First, we have to understand what boiling is all about. At the surface
of a liquid molecules are always evaporating. If we leave a glass of
water out, it will eventually disappear. If we heat the liquid, its
molecules move faster, become more energetic and more molecules go into
the vapour phase. As a consequence, the liquid disappears more quickly.
At the boiling point, molecules all over the liquid, not only at the
surface are energetic enough to go into the vapour phase. They do this
most readily by evaporating into airspaces that exist in the container.
All containers have imperfections where air gets entrapped when a liquid
is introduced. As these air pockets fill with vapour, they expand and
begin to rise. That is why we see streams of bubbles which originate at
the sides or the bottom of the container.
In a microwave oven, the container is not heated, only the water. So
the container actually cools the liquid in contact with it, meaning that
the liquid in the center is always hotter, sometimes by as much as 10
degrees C. But the liquid in the center cannot boil, because there are
no air bubbles for it to evaporate into. By the time the liquid near
the edge of the container reaches the boiling point, the liquid in the
middle is considerably hotter; it is superheated.
The addition of sugar or a tea bag now can spur vigorous boiling. This
is because the surface imperfections introduce trapped air bubbles into
which the superheated liquid vaporizes. Sometimes just picking up the
container can have an explosive effect as the superheated liquid comes
into contact with air bubbles on the periphery. Accidents can be
prevented by putting a plastic spoon into the mug or glass while it is
heating in the microwave. In this case the scare-mongering note about
“exploding coffee” may actually has some basis in fact.
Joe Schwarcz PhD – May 6th/2016
@@ -1,0 +1,96 @@
---
layout: post
title: Cleaning the air with jeans
author: Joe Schwarcz
source: McGill Blogs
---
HYPERLINK
"http://blogs.mcgill.ca/oss/2015/11/17/cleaning-the-air-with-jeans/"
Cleaning the air with jeans
You may want them in your jeans, but you probably want to keep them
away from your genes. They’re “nano” particles of titanium
dioxide, about ten billionths of a meter in diameter that can exhibit
beneficial properties not possessed by their larger cousins, but they
may also have a darker side.
There are more jeans in the world than people. That stat sparked an idea
in the mind of University of Sheffield chemist Tony Ryan. Why not use
people’s penchant for wearing denim to help purify the air? After all,
the International Agency for Research on Cancer (IARC) classifies
outdoor air pollution in Group 1, reserved for substances that are known
to cause cancer in humans. It estimates that there are up to seven
million premature deaths in the world every year as a result of air
pollution.
With thoughts of reducing pollutants such as the nitrogen oxides and
volatile organic compounds emitted by vehicles, power plants,
residential heating, cooking and various consumer products, Ryan, in
partnership with former fashion designer Helen Storey, came up with the
concept of “Catalytic Clothing.”
“Catalytic” apparel uses fabric impregnated with nano-sized
particles of titanium dioxide to degrade air pollutants. “Nano”
means small. So small that the combined surface area of the
nanoparticles that are distributed through any fabric is immense. And
that matters because the action takes place on the surface of the
particles.
Titanium dioxide is a “photocatalyst,” meaning that it can make
chemical reactions happen when exposed to the right wavelength of light,
in this case ultraviolet. The light energy causes it to release
electrons that then target water molecules in the air, breaking them
apart to form extremely reactive hydroxyl radicals that then chop up
organic compounds into simple molecules such as carbon dioxide and
convert nitrogen oxides into water soluble nitric acid. This is not just
theory, it is well established technology that already has commercial
application, for example in “self-cleaning glass.” A thin layer of
titanium dioxide ends window cleaning worries, as long as the climate
provides for sufficient sunshine and rain. The chemical can even be
mixed into concrete, resulting in self-cleaning buildings such as the
Jubilee Church in Rome.
Thanks to titanium dioxide we may never have to confront yellow urinals
again. Coating the ceramic with a layer of titanium dioxide, about a
fiftieth the thickness of human hair, prevents stains from forming. The
technology also has potential in operating rooms where bacteria on floor
and wall tiles can be destroyed with fluorescent light, common in
hospitals, furnishing enough of the right wavelengths. And how about
self-cleaning tiles for the kitchen and bathroom?
Clearly, titanium dioxide photocatalysis is sound technology. But can
wearing jeans treated with this chemical actually have an impact on air
pollution? According to Professor Ryan, yes. He calculates that that if
a third of a million people in Sheffield wore such jeans, nitrogen oxide
levels could be significantly reduced. And there is no need to buy
special jeans. Titanium dioxide particles stick readily to the fabric so
the idea is to add a formulation of the chemical to the water when the
jeans are being laundered. The nano particles will stick until the
fabric degrades.
As is often the case in science, there is a “but.” What happens if
nanoparticles enter the bloodstream? What tissues might they affect?
Titanium dioxide has the potential to damage DNA, but to do that it has
to enter cells. That is a possibility since nanoparticles are smaller
than cells. In the lab, nano titanium dioxide has been shown to damage
DNA in human intestinal cells, but only at doses far higher than what
could ever be ingested.
In any case, people will not be dining on their treated jeans. But they
may be gulping donuts, or a vast array of other foods such as
Gobstoppers, M&Ms, pastries or soy milk that have titanium dioxide added
to them to provide a more pleasing whitened appearance. Only about 5% of
the titanium dioxide is made of nano sized particles, but that has
raised concern because IARC has classified titanium dioxide as possibly
carcinogenic to humans (Group 2B). This classification is based on
inhalation of titanium dioxide dust in an occupational setting, quite a
different exposure than eating a donut with a titanium dioxide enhanced
white sugar coating. Nevertheless consumer activism has resulted in
Dunkin Donuts removing titanium dioxide from the powdered sugar coating
on its products. Maybe it can be redirected into catalyst jeans. We
really don’t need to make junk food look more appealing, do we?
Joe Schwarcz – Nov 17th/2015
@@ -1,0 +1,75 @@
---
layout: post
title: DEET Me Up
author: Joe Schwarcz
source: McGill Blogs
---
HYPERLINK
"http://blogs.mcgill.ca/oss/2016/07/21/deet-me-up-how-best-to-repel-a-mo
squito/" DEET Me Up: How Best to Repel a Mosquito
When it comes to protection from mosquitoes, opinions are abuzz. Burn
citronella candles. Wear repellant bracelets. Douse yourself with
Avon’s Skin-So-Soft. Eat garlic. Take vitamin B1 supplements.
Use concentrated DEET. Use dilute DEET. People are confused.
Needlessly. There are many questions science cannot readily answer,
but the question of what is the most effective mosquito repellant is not
one of them. That’s because it doesn’t take rocket science to
design an appropriate study. You don’t need sophisticated equipment
and you don’t have to extrapolate from rat studies. All you need are
some human volunteers who are willing to stick their bare arms into a
cage of hungry female mosquitoes. And that is exactly what researchers
had fifteen volunteers do at the University of Florida in a study
reported in the New England Journal of Medicine. And now we know what
works and what does not.
This study was very carefully done. Temperature, humidity, density of
the mosquito population and state of hunger of the insects were all
controlled. Sixteen popular products were purchased and tested
repeatedly with the time until first bite being accurately measured.
Lets’ start with what doesn’t work. You can forget about any of
the “repellant” wristbands. They kept mosquitoes away for the
stunning time of about twenty seconds. Avon’s “Skin-So-Soft” may
make your skin feel soft but will only keep the bugs away for about
twenty minutes. After that your skin will get pretty bumpy from all
the bites. Other citronella preparations fared even worse. So unless
you are willing to walk around constantly spraying yourself, forget the
citronella products. So what works? N,N-diethyl-m-toluamide or
“DEET.”
Some people worry about DEET because they’ve heard reports of toxic
reactions and are suspicious of the substance because it is a synthetic
chemical. Whether a substance is synthetic or not has nothing to do
with its safety profile. Indeed DEET has a remarkable safety record.
It is estimated that since its introduction around 1960, about 8 billion
doses have been applied to humans. And this has resulted in fewer than
50 serious toxic effects of which more than 75% resolved with any
further problems. In the handful of cases where there were residual
effects, there was heavy, frequent application over the whole body.
The New England Journal study has now shown that such applications are
not necessary. A DEET concentration of 24% provided five hours of
protection. Even a 5% concentration, which can be used on children,
kept the mosquitoes away for an hour and a half. DEET should not be
used under clothing, on an open cut or with sunscreen. So there it
is. Look for a product that has between 25 and 30% DEET for adults and
apply it every four hours or so. For young children use the 5%
stuff. If you really want something “natural,” although I don’t
know why that should be appealing, “Bite Blocker” made with soy oil
offers about ninety minutes of protection as do products made with
eucalyptus oil. And if you think that citronella has a pleasant smell,
you’re not alone. Mosquitoes like it too.
A recent study by Consumers Union corroborated these results. “Off
Deep Woods” with 98% DEET kept mosquitoes and ticks away for over ten
hours. Products with 20-34% DEET worked for at least five hours. The
best non-DEET product was Repel Plant Based Lemon Eucalyptus which
contains p-menthane-3,8-diol. It worked for about three and a half
hours. Products with picaridin did not work well, neither did a shirt
treated with permethrin.
Joe Schwarcz – July 21st/2016
@@ -1,0 +1,72 @@
---
layout: post
title: Does the Magnetic Laundry System work
author: Joe Schwarcz
source: McGill Blogs
---
HYPERLINK
"http://blogs.mcgill.ca/oss/2016/07/25/you-asked-does-the-magnetic-laund
ry-system-work/" You Asked: Does the Magnetic Laundry System work?
Magnets are fascinating. Imagine the amazement of the ancient Greeks
who discovered that some naturally occurring stones, later named
magnetite because they were found in a region of Greece called Magnesia,
attracted iron. The stones also quickly attracted superstitious beliefs.
Magnetite was said to have had magical powers, the ability to heal the
sick and frighten away evil spirits. Archimedes, in an undoubtedly
apocryphal story, is said to have used magnetite to remove nails from
enemy ships and sink them. Magnets never sank ships, but they were used
to guide them. We are talking about the compass.
Thousands of years ago the Chinese also noted the properties of
naturally occurring magnetite. When made into the shape of a needle and
floated on water, the magnetite always lined up in a north south
direction! By about 1000 AD, the Chinese had developed the compass that
became the key to navigation. But magnets have also been used to
navigate people away from reality. In the 1800s physician Anton Mesmer
had people hold onto magnetized rods to attract disease out of their
body. Mesmerism, as his antics came to be called, often worked. The
success of the treatment had nothing to do with the magnets, rather it
was based on the belief of the patient. Magnets are great placebos.
Today, magnetized bracelets can be purchased to energize the gullible.
And you can buy magnetic laundry disks for insertion into washing
machines to allow laundry to be done without the use of detergents. The
claim is that the magnets ionize water and thereby increase its cleaning
ability. Nonsense.
Advertising for these products often attacks commercial detergents
accusing them of containing cancer causing chemicals and hormone
disruptors. The claim is that the magnetic disks reduce health risks by
eliminating exposure to these substances while also saving money since
there is no need to purchase detergents. Furthermore, use of the disks
prevents the release of toxic substances into the environment. That all
sounds very “green.” References are given to a patent for the
laundry disks, as well as to a study supposedly demonstrating their
cleaning efficacy.
It is important to understand that the only requirement for obtaining a
patent is novelty. In this case, since nobody before had the idea of
putting magnets into a washing machine, the patent was not hard to get.
When it comes to the patent, there is no need to show that the magnets
actually do anything, just that their use in this context is novel. How
about the study carried out by a testing lab that examined the cleaning
efficacy? Technicians actually took bundles of clothes, washed them in a
magnet equipped washing machine and demonstrated they came out cleaner
than they went in. Surprise, surprise! Water is an excellent solvent and
cleans remarkably well even without any detergent. The “study” had
no control. That is, there was no comparison between laundering with
just water and laundering with the magnetized water.
Is there any rationale that the magnets can actually do something? Water
is diamagnetic, which means that it will be repelled by a magnet. But
the effect is very, very, small. If a vial of water is placed on a piece
of floating Styrofoam and a strong magnet is brought close, it will
slowly move away from the magnet. An interesting phenomenon, but nothing
to do with cleaning ability. But there is something about the
advertising for the laundry disks that is not contestable. They are
guaranteed to last for fifty years, a guarantee that is indeed safe
since magnets do not rot. That is more than what can be said about the
claims of their miraculous cleaning properties.
Joe Schwarcz PhD – July 25th/2016
@@ -1,0 +1,102 @@
---
layout: post
title: Hazard and risk
author: Joe Schwarcz
source: McGill Blogs
---
HYPERLINK "http://blogs.mcgill.ca/oss/2015/11/26/hazard-and-risk/"
Hazard and risk
If you watched the news, read newspapers or surfed the web recently
you will have been inundated with pictures of bacon and headlines
describing it as carcinogenic. That’s because the International Agency
for Research on Cancer (IARC) classified processed meats as being
carcinogenic, placing them in the same category as tobacco smoke,
asbestos, oral contraceptives, alcohol, sunshine, X-rays, polluted air,
and inhaled sand. However, it is critical to understand that the
classification is based on hazard as opposed to risk. Hazard can be
defined as a potential source of harm or adverse health effect. Risk is
the likelihood that exposure to a hazard causes harm or some adverse
effect. If a substance is placed in IARC’s Group 1, it means that
there is strong evidence that the substance can cause cancer, but it
says nothing about how likely it is to do so. That likelihood depends on
several factors including innate carcinogenicity, extent of exposure and
personal liability. Ultraviolet light, a component of sunlight, is a
good example to illustrate the difference between hazard and risk
Light can be thought of as being composed of packets of energy called
photons. When a photon impacts a molecule of DNA it can damage it,
triggering an irregular multiplication of cells, in other words, cancer.
X-rays are also made up of photons, but these are more energetic than
the photons of ultraviolet light so they are more likely to damage DNA.
Although both sunlight and X-rays are in Group 1, X-rays are clearly
more capable of triggering cancer than sunlight. But exposure matters. A
single chest X-ray is not a problem but repeated baking in the sun is.
More photons of lower energy can have a greater effect than fewer
photons of greater energy. Then there is individual liability. A person
with dark skin is less at risk for developing cancer than someone with
pale skin even at the same ultraviolet light exposure.
Inhaled sand is also listed in Group 1. That’s because studies have
shown that workers engaged in occupations that can result in inhaling
sand show a significantly increased risk of cancer. But this doesn’t
mean that going to the beach and frolicking in the sand is a risky
business. Tobacco smoke is also in Group 1because there is no doubt that
it causes lung cancer. In fact about ninety percent of all lung cancer
cases can be attributed to smoking. Alcohol is also in this category
because it is known to increase the risk of oral cancers as well as
breast cancer, yet nobody worries about drinking a glass of wine.
Listing processed meat in IARC’s Group 1 just says that like alcohol,
like tobacco, like sunshine, and some 180 other chemicals, mixtures and
exposure circumstances, it is capable of causing cancer. It does not
mean that if you have a bacon lettuce and tomato sandwich you are
putting yourself at risk.
Let’s clarify what is meant by processed meat. Grinding meat into
hamburger does not result in processed meat. But smoking, fermenting or
adding chemicals such as salt or nitrites to either extend the
product’s shelf life or change its taste does. We’re talking about
bacon, sausages, hot dogs, salami, corned beef, beef jerky and ham as
well as canned meat and often meat-based sauces.
The evidence that these tasty morsels are linked to cancer comes from
observational studies, which of course do not prove cause and effect.
But they are quite consistent in demonstrating that populations that
consume lots of processed meats have higher cancer rates, particularly
colorectal cancer, even when corrections are made for smoking, other
foods eaten and activity levels. Furthermore, there are theoretical and
experimental foundations for declaring some components found in
processed meat, like polycyclic aromatics, heterocyclic amines,
nitrites, insulin-like growth factor and heme-iron, carcinogenic.
The evidence is certainly not ironclad, but science rarely is. It comes
down to making educated guesses and evaluating the downside of such
guesses. There is no significant downside to limiting processed meat,
especially if it is replaced by plant products.But the significant
question to ask is how much can we reduce our risk of colorectal cancer
by robbing our taste buds of the taste of bacon and such? The risk of
this cancer in the general population is roughly six in a hundred. After
poring through some 800 peer-reviewed publications, IARC estimates that
eating 50 grams of processed meat every day over a lifetime increases
risk by about 18%. In other words, if a hundred people follow such a
regimen over a lifetime, there will be seven cases of colorectal cancer
instead of six. So for an individual, the chance of getting colon cancer
because of eating processed meats is about 1 in 100. That is a very
small risk, but because there may well be millions of people following
such a diet, the impact on the population can be significant, in
IARC’s estimate, about 34,000 cases a year.
What do we do with this information? A one in a hundred chance is not
insignificant and it makes sense to try to reduce it. That means
consuming less than 50 grams of processed meat a day on average. To do
that we need to keep some numbers in mind. Two to three strips of bacon
add up to 50 grams, as do two slices of ham, 4 slices of salami or one
hot dog. Remember though that we are talking averages here. Certainly a
couple of hot dogs, a salami sandwich and a couple of bacon and egg
breakfasts a week is not a great risk. But if you have a smoked meat
sandwich, well, you have used up your weekly allotment. But remember
that all these numbers are estimates, basically educated guesses, and
are not based on hard evidence.
Joe Schwarcz – Nov 26th/2015
@@ -1,0 +1,45 @@
---
layout: post
title: If you were using
author: Joe Schwarcz
source: McGill Blogs
---
HYPERLINK
"http://blogs.mcgill.ca/oss/2013/05/06/if-you-were-using-%e2%80%9ccathod
ic-protection%e2%80%9d-what-would-you-be-trying-to-protect/" If you
were using “cathodic protection,” what would you be trying to
protect?
You would be trying to prevent iron from rusting. The rusting of iron
is an expensive process. It is estimated that the deterioration of iron
due to corrosion costs billions of dollars a year in Canada. The process
is simple enough in terms of chemistry. Iron reacts with oxygen from the
air to form iron oxide. This is termed an electrochemical reaction
because the oxygen actually steals electrons from the iron. Water is
required for this reaction to proceed, and the process is faster if the
water has substances called electrolytes which can carry an electric
current dissolved in it. Salt is a great electrolyte. And our cars are
exposed to plenty of it in the winter, which explains why Canadian cars
rust so fast. Conversely, airplanes not in use are usually stored in the
Arizona desert where there is virtually no humidity. A process known as
cathodic protection can be used to prevent rust formation. The iron to
be protected is attached to another metal such as zinc or magnesium,
which give up electrons to oxygen more readily than does iron. The so-
called sacrificial cathode will then corrode and the iron will not.
Underground gasoline storage or oil tanks can be protected in this
fashion. This is readily demonstrated with a simple experiment. Take two
nails, immerse them in salt water but attach a piece of zinc to one of
the nails. Watch the difference in corrosion! Rusting can also be
prevented by excluding oxygen and moisture. Paint does this quite well.
Another possibility is to alloy iron with other metals such as chromium
to make stainless steel. In this case chromium reacts with oxygen to
form chromium oxide that deposits as a thin impermeable layer on the
surface of the metal and protects the iron underneath. Iron can also be
coated with a thin layer of another metal which is less prone to
oxidation. So called “tin” cans actually are made of iron with a
thin coating of tin.
Joe Schwarcz – May 6th/2013
@@ -1,0 +1,110 @@
---
layout: post
title: Love it or Hate it
author: Joe Schwarcz
source: McGill Blogs
---
HYPERLINK "http://blogs.mcgill.ca/oss/2016/02/12/love-it-or-hate-it/"
Love it or Hate it
When it comes to food, everyone has likes and dislikes. Chocolate
generally gets favourable comments, spinach less so. But no flavour
seems to elicit the degree of polarizing comments as that of cilantro.
There are websites and Facebook groups dedicated to demonizing cilantro,
likening its aroma to soap or curiously, to dead bugs.
The seeds of the cilantro plant are known as coriander and are even
mentioned in the book of Exodus. Archeologists found some in King
Tutankhamen’s tomb, perhaps placed there with hopes of adding some
spice to the afterlife. The ancient Chinese believed there would be no
need to worry about the afterlife if you consumed cilantro because the
herb conferred immortality. Hippocrates used it as medicine and even
today some people ascribe health benefits to the herb based on its
content of antioxidants, anti-bacterial compounds and minerals. These,
though, are not unique to cilantro, all plants contain varying
quantities of these substances.
Another supposed benefit is cilantro’s ability to chelate heavy
metals. The term “chelate” comes from the Greek meaning “claw”
and refers to compounds that have the ability to remove harmful metal
ions from solution by gripping them like a claw. Some bloggers even push
cilantro as an ingredient in a “detox” salad, claiming it rids the
body of heavy metals. As usual, there is a kernel of truth to the claim,
but that kernel is inflated with nonsense until it pops.
A few studies have shown that cilantro leaves can produce a chelating
effect in water spiked with heavy metals and that cilantro can reduce
absorption of lead when food tainted with it is fed to mice. But these
effects are light years from a salad with cilantro accomplishing any
sort of heavy metal “detoxing” in people. Such a claim would require
a demonstration of there being a heavy metal problem in the first place
and its reduction with cilantro. A PubMed search for “cilantro
detox” yields zero entries. Similarly, there is no basis to some food
faddists’ claim that “cilantro can reduce water weight, is a cancer
fighter and can improve memory with its brain protecting vitamins and
minerals.”
While the scientific literature provides no evidence for health
benefits, it does provide clues when it comes to cilantro’s polarizing
flavour. What we refer to as flavour is the sensation triggered when
molecules in food encounter receptors on our taste buds and in our nasal
passage. Indeed, scent is an integral part of the sensation as evidenced
by cilantro haters not being bothered if they consume the herb while
holding their nose.
Some forty compounds have been isolated from cilantro including a number
in the aldehyde family that are mainly responsible for the aroma and
taste. The composition of the seeds is somewhat different, having
linalool, also found in lavender and cannabis, as a major component. It
has a pleasant floral scent accounting for its use in cleaning agents,
detergents and shampoos. When inhaled it can reduce stress. At least in
lab rats. Rats that inhaled linalool saw a reduction in the elevated
levels of white blood cells induced by stress.
It is the aldehydes in cilantro that cause some people to liken the
scent to soaps and lotions because these compounds are indeed found in
those products. But why only some people? One theory is that the
cilantrophobes are “supertasters” and can taste compounds that
others can’t. Supertasters do exist, but they react to very specific
bitter compounds such as propylthiouracil, while most people taste
nothing. However, there are no such compounds in cilantro and
“supertasters” are no more likely to be cilantro haters than anyone
else.
It seems, though, that people ho abhor cilantro may have some sort of
genetic connection, if we go by an interesting study carried out by Dr.
Charles Wysocki of the Monell Chemical Senses Center in Philadelphia.
Taking advantage of the annual twins festival in Twinsburg, Ohio,
Wysocki had identical and fraternal twins rate the scent of chopped
cilantro. There were definitely lovers and haters, with identical twins
almost always agreeing with their sibling, which was not the case for
fraternal twins. Experiments at Monell have also separated the
components of cilantro using gas chromatography and showed that while
everyone can smell the “soapy” aldehydes, cilantro haters cannot
smell the compounds that make the herb so attractive to its fans.
Interestingly, there is also an ethnocultural connection. A study at the
University of Toronto surveyed 1639 young adults and had them rate their
preference for cilantro on a 9 point scale. East Asians were the most
likely to dislike cilantro with roughly 21% expressing their distaste.
Caucasians were not far behind at 17%. Only 14% of those of African
descent disliked the taste, followed by South Asians at 7%, Hispanics at
4% and Middle Eastern subjects at 3%. These stats roughly parallel the
use of cilantro in the cuisine of these areas suggesting that there is a
connection between liking cilantro and frequency of exposure.
While cilantro’s enemies would rather stick rusty needles into their
eyeballs than eat the fresh herb, they normally don’t object to
cilantro in cooked foods such as pesto. That’s because the herb’s
flavor changes as the volatile aldehydes escape into the air when it is
crushed, cooked or pureed. Cilantro fans of course crave fresh cilantro
and when cooking add the herb at the end stage. As for me, I’m with
Julia Child on this one. Back in 2002 she told Larry King in an
interview that if she found cilantro in a dish she was served she would
pick it out and throw it on the floor. I recognize, though, that there
are people who would jump to catch it before it hit the ground because
they just love the smell and taste of this herb that has pleased some
and irritated others since biblical times.
Joe Schwarcz PhD – Feb 12th/2016
@@ -1,0 +1,68 @@
---
layout: post
title: National Bunsen Burner Day
author: Joe Schwarcz
source: McGill Blogs
---
HYPERLINK
"http://blogs.mcgill.ca/oss/2016/04/14/national-bunsen-burner-day/"
National Bunsen Burner Day
March 31st was National Bunsen Burner Day. Bunsen (1811-1899) should
be remembered. After all, the “Bunsen Burner” is a typical symbol of
chemistry. But there is more to Bunsen than just a burner.
Laboratory workers had long been plagued by sooty, hard-to-control
flames and Bunsen of course knew that oxygen was necessary for
combustion and that soot was the product of incomplete combustion. He
therefore concluded that the secret to a clean flame lay in mixing the
combustible gas with air in just the right proportion.
The prototype Bunsen burner consisted of a metal tube with strategically
drilled holes through which air could enter and mix with the combustible
gas flowing through the tube. A sliding metal cover allowed the operator
to vary the number of open holes and thus control the character of the
flame. Bunsen, however, never patented his invention. He did not believe
that scientists should profit financially from their work; research was
to be done for its own sake.
Why was Bunsen so interested in developing a clean flame? Because he had
a passion for studying the diverse brilliant colors produced by
sprinkling various substances into a fire. He had noted that throwing
sodium chloride (ordinary salt) into a flame always resulted in a bright
orange-yellow glow. The same color appeared if sodium bromide, or indeed
any compound of sodium was cast into the flame. Other elements also
produced characteristic colors. In fact Bunsen discovered the existence
of the elements rubidium and cesium through the colors they produced.
Over a hundred years earlier, Newton had shown how a prism can be used
to separate white light into the colors of the rainbow. Bunsen now
applied this principle to separate the colors of a flame into their
individual components. The spectroscope, an instrument he developed
together with the physicist Kirchoff, allowed unknown substances to be
identified purely by the colors they produced when heated in the flame
of a Bunsen burner.
So, who cares what colors are produced in a flame? Well, just think of
the glorious colors of fireworks. Or the bright red strontium flame of
an emergency roadside flare. Or the yellow glow of a sodium vapor
highway light. The original studies that led to these applications were
painstakingly carried out by Robert Bunsen.
After having long toiled with flames and spectroscopes in the
laboratory, the great man spent years writing up his work for
publication. The day the manuscript was finished, he left it on his desk
and went out to celebrate. When he returned, Bunsen was horrified to see
a smoldering pile of ashes where his treasured treatise had been.
A flask filled with water had been next to the papers and had acted as a
magnifying glass, focussing the sun’s rays and igniting the
manuscript. A lesser man would have surrendered to fate at this point.
But Bunsen, even at an advanced age, doggedly repeated the work and
eventually published the results of his spectroscopic research so that
all the world finally became aware of his burner.
Joe Schwarcz PhD – April 14th/2016
@@ -1,0 +1,32 @@
---
layout: post
title: Should one worry about reboiling water for coffee or tea
author: Joe Schwarcz
source: McGill Blogs
---
HYPERLINK
"http://blogs.mcgill.ca/oss/2015/06/30/should-one-worry-about-reboiling-
water-for-coffee-or-tea/" Should one worry about reboiling water for
coffee or tea?
An article is circulating on the internet about the dangers of
reboiling water and concentrating dissolved chemicals. It amounts to
baseless fear-mongering. Lets consider fluoride as an example. Suppose
you put a liter of water containing 1 ppm fluoride in a kettle and boil
it. You then take 200 mL to make a cup of coffee or tea. That means you
will ingest 0.2 mg of fluoride. If you now let the water keep boiling
until 100 mL evaporates…which would take a long time…and you take
200 mL from the remaining water to make your next cup of coffee, you
will be ingesting 0.22 mg of fluoride. This is an insignificant
difference, even if there were an issue with that amount of fluoride,
which there isn’t. The same argument applies to any other solutes in
water. To imply that making your next cup of coffee from boiled water is
going to have any sort of impact on health is absolute nonsense. With
tea there may actually be a slight difference but that has nothing to do
with taste not toxicity. Boiling drives oxygen out of the water and
deoxygenated water tends to taste more flat.
Dr. Joe Schwarcz – June 30th/2015
@@ -1,0 +1,120 @@
---
layout: post
title: Sugar research left a bitter taste
author: Joe Schwarcz
source: McGill Blogs
---
HYPERLINK
"http://blogs.mcgill.ca/oss/2016/09/25/the-right-chemistry-sugar-researc
h-left-a-bitter-taste/" The Right Chemistry: Sugar research left a
bitter taste
“Is it true that putting a piece of garlic in the rectum at night can
cleanse the body?”
And with that single question posed by an audience member back in 1975,
my chemical focus shifted to food and nutrition. The question came after
one of my first public talks on chemistry at a local library, where I
had described the role chemistry plays in our daily lives, mostly using
dyes, drugs, plastics and cosmetics as examples.
I was sort of taken aback by the question, but managed to stammer
something like “where did you hear that?”
Back came the answer, “from Panic in the Pantry.” After mentioning
that my only experience with garlic had been with rubbing it on toast
with some very satisfying results to the palate, I promised to check out
the reference.
It wasn’t hard to track down Panic in the Pantry in a local bookstore.
The title had suggested some sort of attack on our food system, but this
turned out not to be the case. At least not in the way I had thought.
Flipping through the book I came across terms like “chemophobia,”
“carcinogen,” “additives,” “chemical-free” and “health
foods.” I was intrigued, especially on noting that the book had had
been written by Frederick Stare, a physician with a previous degree in
chemistry who had founded the Department of Nutrition at Harvard’s
School of Public Health, and co-author Elizabeth Whelan. Within a day I
had read Panic in the Pantry from cover to cover and was so captivated
that I dove into the turbid waters of nutrition and food chemistry with
great enthusiasm. Ever since then, I have been trying to keep my head
above water, buffeted by the growing waves of information and
misinformation.
Panic in the Pantry focused on what the authors believed were
unrealistic worries about our food supply, vigorously attacking the
popular lay notion that “if you can’t pronounce it, it must be
harmful.” Yes, that daft message was around long before the Food Babe
made it her anthem. In truth, the risks and benefits of a chemical are a
consequence of its molecular structure, and are determined by
appropriate studies, not by the number of syllables in its name. Stare
and Whelan also challenged the “Delaney Clause,” a piece of U.S.
legislation stating that no additive shall be deemed safe if it has been
shown to cause cancer in any species upon any type of exposure. They
pointed at studies that showed very different effects of chemicals in
rodents and humans and maintained that it was unrealistic to condemn
additives if exposure was not taken into account. “Too much sun can
cause skin cancer, but does that mean we should stay indoors all the
time?” they asked.
What about the curious case of the clove of garlic in the rectum? An
excellent example of a misinterpretation of information, something that
I have seen much too often. In a discussion of food faddism through the
ages, the authors introduced the antics of one Adolphus Hohensee, who
had forged a career as a “health food” advocate after his real
estate business had landed him in jail for mail fraud. The dietary guru
told his audiences that the sex act should last an hour, and if they did
not measure up to this level of sexual adequacy it was because they had
a diet laden with additives.
Hohensee’s answer to the chemical onslaught was a clove of garlic in
the rectum at night, with proof of its efficacy being the scent of
garlic on the breath in the morning. Obviously, the garlic had worked
its way from bottom to top, cleansing everything in-between. Far from
promoting this regimen, Stare and Whelan had used it to highlight the
extent of nutritional quackery.
I found most of the arguments in Panic in the Pantry highly palatable,
but there was a discussion of one chemical that left a somewhat bitter
taste. That chemical was sugar. I had been quite taken by Pure, White
and Deadly, a 1972 book by British physiologist John Yudkin, who made a
compelling case linking sugar to heart disease, cavities, diabetes,
obesity and possibly some cancers. Stare dismissed sugar as a culprit,
implicating saturated fats as the cause of coronary disease. That to me
seemed not to meet the standard of evidence that was applied to other
issues in Panic in the Pantry.
As it turns out, there was a reason for Stare’s dismissal of sugar as
a health problem. In 1965, the Sugar Research Foundation (SRF), the
industry’s trade association, asked Stare to sit on its advisory board
because of his expertise in the dietary causes of heart disease. The
sugar industry was extremely worried about Yudkin’s growing influence
and decided to embark on a major program to take the focus off sugar and
direct it toward fats. Stare’s defence of sugar as a quick energy food
that should be put in coffee or tea several times a day and calling Coca
Cola a healthy between meals snack was welcomed by the industry.
As we have now learned from historical documents brought to light in a
paper in the Journal of the American Medical Association, the SRF paid
members of Stare’s department to carry out a literature review,
overseen by Stare, designed to point a finger at fats while expressing
skepticism about sugar’s supposed criminality. That review was
published in the New England Journal of Medicine without any disclosure
of sugar industry funding and successfully steered readers away from
associating sugar with heart disease. While Stare, who died in 2002, was
correct about many aspects of unfounded chemophobia, his reputation has
now been tarnished by the undeclared payments received by his department
from the sugar industry.
Sugar, as we now know, is not as innocent as Stare had claimed. But at
least he never did suggest garlic in the rectum to cleanse toxins. As
far as I know, neither has the Food Babe.
Dr. Joe Schwarcz PhD
Sept 25th/2016
@@ -1,0 +1,63 @@
---
layout: post
title: The U.S. Toxic Substances Control Act TSCA
author: Joe Schwarcz
source: McGill Blogs
---
HYPERLINK
"http://blogs.mcgill.ca/oss/2016/08/27/the-u-s-toxic-substances-control-
act-tsca/" The U.S. Toxic Substances Control Act (TSCA)
Amidst the cacophony of jingoist, vacuous blather at the Republican
Convention there were some noteworthy phrases that probably slipped by
most viewers. A number of speakers talked about the need to reign in the
activities of the Environmental Protection Agency, the “EPA.” That
is something one would expect from Republicans who want as little
government interference in their life as possible. But these are the
same Republicans who voted to update the 1976 Toxic Substances Control
Act that finally was passed in June by Congress with bipartisan approval
after ten years of debate. This update was very much needed because
significant information has been accumulated since 1976 about exposure
to chemicals in the environment and their potential effect on health.
The old law required companies to register new chemicals that would
enter commerce with the EPA but there was no requirement to furnish any
safety data, and there was no provision for EPA to tackle the risks
associated with chemicals already on the market at the time. The
assumption was that chemicals are safe unless shown to be otherwise. The
EPA did have the power to ban a chemical, but the burden of proof of
harm was on the agency. Also, the economic downsides had to be factored
in before the use of any chemical was limited. With companies
introducing about 700 chemicals every year, and the EPA inventory
building up to some 85,000 substances, the task of ferreting out
dangerous ones is overwhelming. While determining risk when exposure is
high, such as in an occupational setting, is relatively easy,
determining risk to consumers who may be exposed to some chemical in
tiny amounts over a long period is daunting.
But under the new law, EPA has to examine a chemical before it is put on
the market and make a decision about safety. The risk assessment will
take into account how a chemical is used. For example, a fluorinated
compound may be deemed to be fine for use in airplane fire
extinguishers, but not as an oil repellant in pizza boxes. An important
new feature is that the agency will now have the authority to ask for
information from producers about studies that have been carried out and
can even ask for further studies. Another new facet is that EPA does not
have to consider the economic implications of declaring a substance to
be toxic. Furthermore, it is going to be much tougher for a company to
withhold information claiming trade secrecy.
There are also 90 chemicals that have been identified as meriting
investigation and possible regulation with EPA having to adhere to
mandatory deadlines. The new bill has the support of the chemical
industry because it should reduce consumer angst given that EPA will now
be charged with examining the safety of chemicals before they go on the
market. But here is the issue. While Republicans in the House voted for
the bill, they also voted to cut the EPA’s funding and staffing for
2017. If EPA is going to carry out its new duties effectively, it will
need more, not less funding. The plan is that some of the shortfall will
be offset by charging companies fees for submitting chemicals for EPA to
review. That may not sit well with Republicans.
Joe Schwarcz PhD – Aug 27th/2016
@@ -1,0 +1,54 @@
---
layout: post
title: Tires and ice dont make for a good mix
author: Joe Schwarcz
source: McGill Blogs
---
HYPERLINK
"http://blogs.mcgill.ca/oss/2014/01/10/tires-and-ice-dont-make-for-a-goo
d-mix/" Tires and ice don’t make for a good mix
Ice is great in a beverage or on a skating rink but we don’t want it
on our streets. How do we melt it? Potassium acetate, sodium chloride,
calcium chloride, magnesium chloride or urea will do the job. They all
interfere with the formation of ice crystals and can be used to melt
ice. They do, however, differ in effectiveness, potential harm to the
environment and cost.
Sodium chloride, or common salt, is cheap and can melt ice down to about
-20C. At lower temperatures salt can be mixed with “beet juice”
which is actually the molasses left behind when sugar is produced from
sugar beets. Mixing salt with beet juice allows less salt to be used
which results in a “greener” process since salt can damage soil and
vegetation, contaminate surface and ground water and speed up the
corrosion of concrete and metals. Corrosion of metals is a process
whereby the metal react with oxygen. This requires the transfer of
electrons among substances and such transfer is facilitated by the
presence of ions, such as sodium and chloride. Substances that
dissolve to form ions in solution are called electrolytes and speed up
the rusting process. That’s why cars in Canada rust and those in
Arizona do not. That is also why airplanes not in use are stored in
the Arizona desert.
Not all electrolytes speed up corrosion to the same extent. Potassium
acetate is much more environmentally friendly than salt but is twenty
times more expensive. Calcium chloride melts snow and ice much faster
than sodium chloride, is less corrosive but does damage vegetation and
wildlife. It also costs more than salt. Magnesium chloride is also
less corrosive, but works only down to -15C and costs five times more
than salt. Urea is non-corrosive, does not damage vegetation but only
melts ice down to -4C. There is yet another issue with salt. It
works more effectively if the grains can be prevented from clumping.
To reduce caking, small amounts of sodium ferrocyanide are added. In
the presence of sunlight, this can break down and release cyanide which
can be washed into waterways and damage aquatic life.
Ethlylene glycol or propylene glycol are the substances used to de-ice
airplanes because they are non-corrosive. These liquids are collected
and recycled but some is inevitably lost to the environment. Obviously
there is no perfect way to melt ice and snow. But not using these
substances would result in loss of life. As with so many scientific
issues, it is a question of evaluating risk versus benefit.
Joe Schwarcz – Jan 10th/2014
@@ -1,0 +1,65 @@
---
layout: post
title: What is natamycin
author: Joe Schwarcz
source: McGill Blogs
---
HYPERLINK
"http://blogs.mcgill.ca/oss/2016/03/10/you-asked-what-is-natamycin/"
You Asked: What is natamycin?
“The customer is always right,” is a time-honoured adage in
marketing. It holds true even if the customer is wrong. If the customer
does not want “artificial” preservatives” in food, industry will
comply, whether that move is supported by science or not. Of course no
company wants to poison its customers, so eliminating preservatives is a
risky business. What’s the answer? Look for a “natural”
preservative. That will satisfy the consumer who has a disdain for
anything artificial, and at the same time will reduce the worry for the
producer about marketing an unsafe product.
Kraft, for example, has announced that, at least in the U.S., it will be
replacing artificial preservatives with natural ones in its cheese
products. This boils down to not much more than a question of semantics.
Sorbic acid and its salts, the “artificial” preservatives that have
been used, are to be replaced by natamycin, an antifungal compound
produced by soil bacteria. Although many cheeses are actually mould
ripened, with blue cheese being the classic example, cheese is also
prone to infection by a variety of rogue moulds that can cause spoilage.
Sorbic acid and its salts can prevent the growth of moulds, yeast and
fungi, even when used at concentrations of less than 0.1%. It was back
in 1859 that Professor August Wilhelm Hofmann first isolated sorbic acid
by distilling the oil obtained from the berries of the rowan tree. This
is the same Professor Hofmann who was enticed to England by Prince
Albert to head up the newly created Royal College of Chemistry and who
essentially founded the synthetic dye industry.
So, doesn’t the fact that sorbic acid can be isolated from berries
make it a “natural” substance? Yes. And I suppose there would be no
clamoring to remove it from food if this is how it were produced. But
distilling sorbic acid from rowan berries is not an economical process
and would not do for the estimated 30,000 tons needed every year by the
food industry. But sorbic acid can also be readily produced by a number
of synthetic methods, including the reaction of crotonaldehyde with
ketene, both of which can be made from compounds isolated from
petroleum. This synthesis is economically viable and is the way that
sorbic acid is produced. Any chemical is defined by its molecular
structure which does not depend on the route by which it was produced.
The sorbic acid produced by the rowan berry is identical to the sorbic
acid produced by chemical synthesis, but because the latter was not
extracted from a natural source, it is termed “artificial,” and
therefore in the eyes of some people, suspect. The fact is that sorbic
acid, irrelevant of the source, is a food additive that has passed all
the regulatory hurdles just like its replacement, natamycin.
Natamycin is an antifungal agent produced by a soil bacterium that was
first found in South Africa’s Natal province, hence the name. Since
bacteria occur in nature, any of the chemicals they crank out can be
classified as “natural.” But curiously a substance that occurs in
nature, like sorbic acid, is termed an artificial preservative when it
is synthesized in the lab. Natamycin may be natural, but it would not be
so appealing to people if they knew they were eating the waste product
of dirt bacteria. Not that there is anything wrong with that.
Joe Schwarcz PhD – March 10th/2016
@@ -1,0 +1,186 @@
---
layout: post
title: Why Does Copper Oxidize and Turn Green
author: Joe Schwarcz
source: McGill Blogs
---
Why Does Copper Oxidize and Turn Green?
The natural color of copper is peachy or pinkish-white, with a bright
metallic luster. It is one of the very few elements, whose natural color
is neither white nor gray. However, it undergoes oxidation reaction and
turns green after being exposed to air.
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Fast Fact
A prime example of copper oxidation is the Statue of Liberty, wherein a
green color has developed on the structure's surface due to redox, and
not due to effect of acid rain, as generally believed by people.
According to the Copper Development Association, until now, the
oxidation of the statue's copper skin is about 0.005 inch.
Copper is a metallic element with atomic number 29, and is represented
by the symbol 'Cu' (Cuprum). It is a malleable (can be shaped into a
thin sheet) and ductile (can be shaped into a thin wire) element. In
humans and animals, it is an essential metal that is found in the body
cells and tissues. Due to high thermal and electrical conductivity,
copper is used in many aspects of life, such as building materials,
thermal and electrical conductors, and in the manufacture of various
metallic alloys. In fact, its use can be traced back to the ancient
times and early civilizations. This is evident from the old copper
crafts, copper wares, and other material remnants of the past
civilizations. Due to its chemical properties, copper ranks third as an
industrial metal, next to aluminum and iron. In nature, copper is
usually found in association with sulfur, which is then purified by
means of other techniques.
Examples of Oxidation
◆ Oxidation of iron is referred to as 'rust', and it leads to the
corrosion and formation of a flaky, reddish-brown outer layer.
◆ Another example is the oxidation of aluminum, leading to the
development of a flaky white layer. This is usually seen on aluminum
doors and windows after heavy rainfall.
◆ When an apple is cut and the surface is exposed to air, it turns
brown.
Oxidation of Copper and Changing of Color
Oxidation is a phenomenon, whereby an element loses electrons (and/or
hydrogen) on interacting with another element. Similar to iron and
aluminum, the element copper undergoes the process of oxidation, if it
is exposed to air. If the atmosphere consists of high humidity moisture,
then this process is faster. The copper metal reacts with oxygen,
resulting in the formation of an outer layer of copper oxide, which
appears green or bluish-green in color. This layer is known as the
patina.
Unlike other destructive oxidation processes, the patina acts as a
protective layer, and it does not cause any weakness in the metal. Thus,
copper is considered as an important element that is resistant to
corrosion. The patina prevents further corrosion
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Ɱ琠楨慬敹獩猠敥湯琠敨爠潯瑦灯景漠摬戠極
摬湩獧湡捡獴愠慷整灲潲景湩湡畳牰潯
楦杮挠慯刍慥瑣潩獮
☞ The oxidation process is characterized by the formation of three
main products: azurite, malachite, and brochantite. These minerals
impart the characteristic bluish-green color to oxidized copper metal
and form the patina layer. Simply speaking, it is a redox reaction
wherein both oxidation and reduction take place at the same time.
☞ Firstly, copper donates electrons while reacting with oxygen to form
copper oxide, which is reddish brown in color. This can be represented
as:
4Cu + O2 = 2Cu2O (copper oxide) ---- equation 1
☞ Cu2O again reacts with oxygen to form CuO, which is black in color:
2Cu2O + O2 = 4CuO ---- equation 2
☞ The atmosphere also consists of various pollutants like sulfur
dioxide, carbon monoxide, carbon dioxide, etc. In areas where combustion
of coal takes place, sulfur fumes are present on a large scale, as
sulfur is an impurity present in most of the coal types. Copper oxide
reacts with this element to form blue-colored copper sulfate (CuS),
which may further react with carbon dioxide and moisture present in air
to form the patina layer.
Alternatively, the copper oxide may also directly react with CO2, H2O,
and sulfur oxides to form the compounds brochantite, malachite, and
azurite:
☞ Brochantite is mainly formed when high level of sulfur fumes are
present. It is green in color, and is also known as hydrated copper
sulfate.
4CuO + SO3 + 3H2O = Cu4SO4(OH)6 (brochantite) ---- equation 3
☞ Malachite is a green-colored, naturally formed compound, and along
with azurite, it comprises greenish-blue colored, semi-precious mineral
stones known by the same names. This indicates that oxidation of copper
also takes place in naturally formed rocks and gems, apart from copper
utensils, statues, rooftops, etc.
2CuO + CO2 + H2O = Cu2CO3(OH)2 (malachite) ---- equation 4
☞ Azurite is also known as hydrated copper carbonate, and it imparts a
slight bluish tinge to the oxidized metal. It is formed near areas that
are mined for copper.
3CuO + 2CO2 + H2O = Cu3(CO3)2(OH)2 (azurite) ---- equation 5
How to Oxidize Copper
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½
w
re several methods to oxidize copper at home using daily essentials like
salt, kitchen ammonia, baking soda, water, etc. By this technique, you
can impart an antique or old-style feel to your desirable copper items,
like coins, medals, showcase pieces, etc.
◆ Firstly, clean the copper metal with mild detergent and water, and
wipe evenly in a single direction.
◆ In a steel utensil, mix about half tablespoon salt, half tablespoon
baking soda, and about 15 oz. of ammonia in half liter of water.
◆ Fill this solution in a spray bottle and spray the copper item at
least once in a day. After few weeks, a green-colored patina will start
covering the metal surface.
◆ It is better to perform this technique outdoors to get smoother and
faster-developing carbonate layers.
◆ To oxidize smaller objects like copper coins, a simpler method is to
hang them in a jar without touching the sides and the bottom.
◆ They should be cleaned with alcohol and washed with detergent before
attaching them to the jar with a thread.
◆ The jar bottom is filled with half a centimeter of ammonia, and as
the fumes start reaching the copper surface, close the jar with a lid.
◆ In a couple of hours, a clear green layer starts forming on their
surface. Unscrew the lid and remove the coins after a desirable
thickness of patina has been developed.
For preventing oxidation, the best way is to protect the surfaces, which
are likely to be exposed to air and water, with the help of a protective
coat. This way, the metal surface is prevented from reacting with oxygen
and/or water. You can also apply lemon on the copper surface to remove
any patina layer of carbonates that have formed on the oxidized items.
ls, showcase statues, pipes, etc., is to immerse them into a solution
consisting of water, vinegar, and table salt. Heat the water till
boiling point, and leave the items immersed till a couple of hours.
After removing them, clean the items with soap or detergent to get back
the shiny copper coat.
@@ -1,0 +1,41 @@
---
layout: post
title: Why does coffee heated up in the microwave foam up when sugar is added
author: Joe Schwarcz
source: McGill Blogs
---
HYPERLINK
"http://blogs.mcgill.ca/oss/2013/06/16/why-does-coffee-heated-up-in-the-
microwave-foam-up-when-sugar-is-added/" Why does coffee heated up in
the microwave foam up when sugar is added?
This is due to a phenomenon known as superheating. But first, we have
to understand what boiling is all about. At the surface of a liquid
molecules are always evaporating. If we leave a glass of water out, it
will eventually disappear. If we heat the liquid, its molecules move
faster, become more energetic and more molecules go into the vapour
phase. As a consequence, the liquid disappears more quickly. At the
boiling point, molecules all over the liquid, not only at the surface
are energetic enough to go into the vapour phase. They do this most
readily by evaporating into airspaces that exist in the container. All
containers have imperfections where air gets entrapped when a liquid is
introduced. As these air pockets fill with vapour, they expand and begin
to rise. That is why we see streams of bubbles which originate at the
sides or the bottom of the container. Now, in a microwave oven, the
container is not heated, only the water. Since the container stays cool
it actually cools the liquid that is in contact with it, meaning that
the liquid in the center is always hotter, sometimes by as much as 10
degrees C. But the liquid in the center cannot boil, because there are
no air bubbles for it to evaporate into. By the time the liquid near the
edge of the container reaches the boiling point, the liquid in the
middle is considerably hotter; it is superheated. The addition of sugar
or a tea bag now can spur vigorous boiling. This is because the surface
imperfections introduce trapped air bubbles into which the superheated
liquid vaporizes. Accidents can be prevented by putting a plastic spoon
into the mug or glass while it is heating in the microwave. So now go
and experiment. But take care!
Joe Schwarcz – June 16th/2013
@@ -1,0 +1,8 @@
<aside class="featured-posts">
<h3>{{ site.featured_posts_title}}</h3>
<ul>
{% for post in site.featured_posts %}
<li><a href="{{ post.url }}">{{ post.title }}</a></li>
{% endfor %}
</ul>
</aside>
@@ -1,0 +1,36 @@
{% if page.layout == 'post' %}
{% assign description = page.excerpt %}
{% else %}
{% assign description = site.description %}
{% endif %}
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<meta http-equiv="X-UA-Compatible" content="IE=edge" />
<meta name="description" content="{{ description | newline_to_br | strip_newlines | replace: '<br />', ' ' | strip_html | strip | truncate: 160 }}" />
<link rel="canonical" href="{{ site.url }}{{ page.url }}" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<link rel="stylesheet" href="/assets/main.css"/>
<link rel="alternate" type="application/rss+xml" title="{{ site.title }}" href="/feed.xml" />
<title>{% if page.title == "Home" %}{{ site.title }}{% else %}{{ page.title }} · {{ site.title }}{% endif %}</title>
{% if page.layout == 'post' %}
<script type="application/ld+json">
{
"@context": "https://schema.org",
"@type": "BlogPosting",
"author": "{{ site.author.name }}",
"datePublished": "{{ page.date | date_to_xmlschema }}",
"headline": "{{ page.title }}",
"url": "{{ site.url }}{{ page.url }}",
"inLanguage": "en-US",
"isFamilyFriendly": "true",
"keywords": "{{ page.tags| join: ", " }}",
"image": "{{ site.url }}/favicon.ico",
"mainEntityOfPage": {
"@type": "WebPage",
"@id": "{{ site.url }}{{ page.url }}"
}
}
</script>
{% endif %}
</head>
@@ -1,0 +1,4 @@
<nav class="top-nav">
<a class="nav-item" href='/'>Readings</a>
{% if site.javascript_enabled %}| <a class="nav-item dark-light-switch" href="#"></a>{% endif %}
</nav>
@@ -1,0 +1,14 @@
<!DOCTYPE html>
<html lang="en">
{% include head.html %}
<body>
<div class="container">
{% include nav.html %}
<hr class="stylish"/>
{{ content }}
</div>
{% if site.javascript_enabled %}
<script src="/assets/main.js"></script>
{% endif %}
</body>
</html>
@@ -1,0 +1,17 @@
---
layout: default
---
<header>
<h1>{{ page.title }}</h1>
</header>
<hr class="stylish"/>
<main role="main">
<article>
{{content}}
</article>
</main>
@@ -1,0 +1,104 @@
---
layout: default
---
<script src="https://cdnjs.cloudflare.com/ajax/libs/pdfmake/0.1.71/pdfmake.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/pdfmake/0.1.71/vfs_fonts.min.js"></script>
<header>
<h1>{{ page.title }}</h1>
</header>
<hr class="stylish" />
<main role="main">
<div class="content dongxi">
{{content}}
</div>
<div class="magic">
<form id="gimmick">
<label>Title of Article:</label>
<input type="text" value="{{ page.title }}" /> <br />
<label>Author:</label>
<input type="text" value="{{ page.author }}" /> <br />
<label>Source:</label>
<input name="title" type="text" value="{{ page.source }}" /> <br />
<label>Main idea:</label>
<textarea cols="30" rows="2"></textarea><br />
<label>Idea 1:</label> <br />
<textarea cols="30" rows="4"></textarea><br />
<label>Idea 2:</label> <br />
<textarea cols="30" rows="4"></textarea><br />
<label>Idea 3:</label> <br />
<textarea cols="30" rows="4"></textarea><br />
<label class="inline">Vocab 1:</label> <input type="text" value="" /> <br/>
<label class="inline">Definition 1:</label> <input type="text" value="" /> <br/>
<label class="inline">Vocab 2:</label> <input type="text" value="" /> <br/>
<label class="inline">Definition 2:</label> <input type="text" value="" /> <br/>
<label class="inline">Vocab 3:</label> <input type="text" value="" /> <br/>
<label class="inline">Definition 3:</label> <input type="text" value="" /> <br/>
<label>Outcome, Ending, or Future Projections</label> <br />
<textarea cols="30" rows="4"></textarea><br />
<label class="inline">Discussion Q1:</label> <input type="text" value="" /> <br/>
<label class="inline">Discussion Q2:</label> <input type="text" value="" /> <br/>
<label class="inline">Discussion Q3:</label> <input type="text" value="" /> <br/>
</form>
<button value="Submit" id="drSubmit">Submit</button>
<p id="demo"></p>
</div>
</main>
<script>
document.getElementById('drSubmit').onclick = function() {
var x = document.getElementById("gimmick");
pdfMake.createPdf(
{
content: [
{text: 'Title of Article', style: 'header'},
x.elements[0].value,
'Author: '.concat(x.elements[1].value),
'Source: '.concat(x.elements[2].value),
{text: 'Main Idea', style: 'header'},
x.elements[3].value,
{text: 'Detail 1', style: 'header'},
x.elements[4].value,
{text: 'Detail 2', style: 'header'},
x.elements[5].value,
{text: 'Detail 3', style: 'header'},
x.elements[6].value,
{text: 'Vocabulary Words', style: 'header'}, {
ul: [
''.concat(x.elements[7].value, ' → ', x.elements[8].value),
''.concat(x.elements[9].value, ' → ', x.elements[10].value),
''.concat(x.elements[11].value, ' → ', x.elements[12].value)
]
},
{text: 'Outcome/Future Projections', style: 'header'},
x.elements[13].value,
{text: 'Discussion Questions', style: 'header'},
{
ul: [
x.elements[14].value,
x.elements[15].value,
x.elements[16].value
]
}
],
defaultStyle: {
fontSize: 12
},
styles: {
header: {
fontSize: 18,
bold: true,
margin: [0, 10, 5, 5]
}
},
pageMargins: [ 60, 80, 60, 80 ]
}
).download('{{ page.title }}');
}
</script>
@@ -1,0 +1,323 @@
* {
margin: 0;
padding: 0;
}
html, body {
height: 100%;
}
body {
font-size: 16px;
font-family: var(--typography__default);
font-weight: 400;
display: flex;
flex-direction: column;
margin: 8px auto;
margin-left: 10px;
}
.container {
flex: 1 0 auto;
}
footer {
flex-shrink: 0;
}
*, iframe, img, video {
word-wrap: break-word;
max-width:100%;
}
img {
display: block;
margin: 0 auto;
}
code, pre {
font-family: monospace;
background-color: #eee;
letter-spacing: 1px;
font-size: 0.9rem;
padding: 2.5px;
overflow-x: auto;
}
.highlight {
position: relative;
border-radius: 5px;
* {
font-family: monospace, monospace;
background-color: unset;
padding: unset;
letter-spacing: unset;
}
& > pre {
padding: 8px 12px;
& > code::before {
content: attr(data-lang);
position: absolute;
right: 20px;
top: -10px;
padding: 0 7.5px;
border: 1px solid #828282;
border-radius: 5px;
text-align: center;
color: #8fbc8f;
background-color: #1a1a1a;
}
.lineno {
color: #608079;
padding-right: 5px;
margin-right: 10px;
border-right: 1px solid #656565;
}
}
}
a {
color: #333;
}
a:hover {
background-color: #333;
color: #eee;
}
.post-date {
width: 5em;
flex-shrink: 0;
}
.post-wrapper {
display: flex;
margin: 0.8em 0;
font-size: 1.25rem;
}
.prev {
max-width: 50%;
float: left;
text-align: left;
}
.next {
max-width: 50%;
float: right;
text-align: right
}
.pagination {
font-size: 1.25rem;
padding: 1rem 0;
}
.pagination::after {
content: "";
clear: both;
display: block
}
blockquote {
margin: 0;
padding: 0.5em;
border-left: 5px solid black;
font-size: 1.25rem;
line-height: 1.6em;
color: #333;
font-style: italic;
}
.title-tags {
color: #777;
font-size: 1.125rem;
}
.tag-box {
text-transform: capitalize;
}
.nice-title {
text-transform: capitalize;
}
p {
font-size: 16px;
color: #333;
margin: 1.25rem 0;
}
.tags {
background-color: #444;
color: #fff;
padding: 2px 5px;
border-radius: 2px;
text-decoration: none;
}
h1 {
font-size: 1.75rem;
margin: 0.75rem 0;
letter-spacing: 0.5px;
}
h2 {
margin: .75rem 0;
letter-spacing: .5px;
}
h3 {
font-size: 1.5rem;
margin: 0.75rem 0;
letter-spacing: 0.5px;
}
h4 {
font-size: 1.1rem;
margin: 0.75rem 0;
letter-spacing: 0.5px;
}
h5, h6 {
margin: 0.75rem 0;
letter-spacing: 0.5px;
}
section h3 {
margin-top: 40px;
font-size: 1.25rem;
}
h3.home-page-heading {
margin: 5px 0;
display: inline-block;
}
.tags-container {
margin: 10px auto;
}
ul, ol {
padding-left: 20px;
}
li {
font-size: 1.25rem;
line-height: 1.6em;
color: #333;
}
figure {
width: 100%;
margin: 0;
}
figcaption {
text-align: center;
font-size: 1.125rem;
line-height: 1.6em;
color: #333;
}
hr.stylish {
border: 0;
height: 1px;
background-image: linear-gradient(to right, rgba(0, 0, 0, 0.90), rgba(0, 0, 0, 0.45), rgba(0, 0, 0, 0));
margin: 5px 0;
}
.nav-item {
border: none;
}
button {
padding: 5px 10px;
color: white;
background: #272822;
border-radius: 5px;
font-weight: bold;
cursor: pointer;
&:hover {
opacity: 0.7;
}
}
details[open] summary ~ * {
animation: sweep .4s ease-in-out;
}
@keyframes sweep {
0% {opacity: 0; margin-top: -10px}
100% {opacity: 1; margin-top: 0px}
}
.home-main {
margin: 1rem 0;
}
._progress-wrapper {
position: fixed;
width: 100%;
height: .33rem;
top: 0;
left: 0;
z-index: 100;
background-color: rgb(204, 204, 204);
opacity: 0.9;
}
#_progress {
--scroll: 0%;
background: linear-gradient(to right, rgb(51, 51, 51) var(--scroll), transparent 0);
width: 100%;
height: 100%;
}
.featured-posts {
padding: .75rem 0 1rem;
}
table {
width: 100%;
border-collapse: collapse;
th, td {
padding: 5px;
}
}
.content {
margin: 1rem 0;
}
// media queries
@media screen and (max-width: 700px) {
body {
margin: 8px;
}
}
@media screen and (max-width: 370px) {
.nav-item {
font-size: 0.8rem;
}
}
.dongxi {
width: 50%;
float: left;
overflow-y: scroll;
overflow-x: auto;
}
.magic {
width: 50%;
float: right;
overflow-y: scroll;
overflow-x: auto;
}
@@ -1,0 +1,4 @@
:root {
--color__gray--light: rgb(191, 191, 191);
--color__gray--dark: rgb(26, 26, 26);
}
@@ -1,0 +1,50 @@
body.dark {
background-color: var(--color__gray--dark);
color: var(--color__gray--light);
a {
color: var(--color__gray--light)
}
a:hover {
background-color: var(--color__gray--light);
color: var(--color__gray--dark);
}
p {
color: var(--color__gray--light);
}
blockquote {
border-left: 5px solid var(--color__gray--light);
color: var(--color__gray--light)
}
code, pre {
color: var(--color__gray--dark);
font-family: var(--typography__default);
}
.tags {
background-color: var(--color__gray--light);
color: var(--color__gray--dark);
}
li {
color: var(--color__gray--light)
}
figcaption {
color: var(--color__gray--light)
}
hr.stylish {
background-image: linear-gradient(to right, rgba(white, 0.90), rgba(white, 0.45), rgba(white, 0));
}
input {
background-color: var(--color__gray--dark);
color: var(--color__gray--light)
}
input::placeholder {
color: var(--color__gray--light)
}
._progress-wrapper {
background-color: rgb(51, 51, 51);
}
#_progress {
background: linear-gradient(to right, rgb(204, 204, 204) var(--scroll), transparent 0);
}
}
@@ -1,0 +1,5 @@
@import 'constants';
@import 'typography';
@import 'darkmode';
@import 'syntax-highlighter';
@import 'common';
@@ -1,0 +1,70 @@
.highlight .hll { background-color: #49483e }
.highlight { background: #272822; color: #f8f8f2 }
.highlight .c { color: #75715e }
.highlight .err { color: #960050; background-color: #1e0010 }
.highlight .k { color: #66d9ef }
.highlight .l { color: #ae81ff }
.highlight .n { color: #f8f8f2 }
.highlight .o { color: #f92672 }
.highlight .p { color: #f8f8f2 }
.highlight .ch { color: #75715e }
.highlight .cm { color: #75715e }
.highlight .cp { color: #75715e }
.highlight .cpf { color: #75715e }
.highlight .c1 { color: #75715e }
.highlight .cs { color: #75715e }
.highlight .gd { color: #f92672 }
.highlight .ge { font-style: italic }
.highlight .gi { color: #a6e22e }
.highlight .gs { font-weight: bold }
.highlight .gu { color: #75715e }
.highlight .kc { color: #66d9ef }
.highlight .kd { color: #66d9ef }
.highlight .kn { color: #f92672 }
.highlight .kp { color: #66d9ef }
.highlight .kr { color: #66d9ef }
.highlight .kt { color: #66d9ef }
.highlight .ld { color: #e6db74 }
.highlight .m { color: #ae81ff }
.highlight .s { color: #e6db74 }
.highlight .na { color: #a6e22e }
.highlight .nb { color: #f8f8f2 }
.highlight .nc { color: #a6e22e }
.highlight .no { color: #66d9ef }
.highlight .nd { color: #a6e22e }
.highlight .ni { color: #f8f8f2 }
.highlight .ne { color: #a6e22e }
.highlight .nf { color: #a6e22e }
.highlight .nl { color: #f8f8f2 }
.highlight .nn { color: #f8f8f2 }
.highlight .nx { color: #a6e22e }
.highlight .py { color: #f8f8f2 }
.highlight .nt { color: #f92672 }
.highlight .nv { color: #f8f8f2 }
.highlight .ow { color: #f92672 }
.highlight .w { color: #f8f8f2 }
.highlight .mb { color: #ae81ff }
.highlight .mf { color: #ae81ff }
.highlight .mh { color: #ae81ff }
.highlight .mi { color: #ae81ff }
.highlight .mo { color: #ae81ff }
.highlight .sa { color: #e6db74 }
.highlight .sb { color: #e6db74 }
.highlight .sc { color: #e6db74 }
.highlight .dl { color: #e6db74 }
.highlight .sd { color: #e6db74 }
.highlight .s2 { color: #e6db74 }
.highlight .se { color: #ae81ff }
.highlight .sh { color: #e6db74 }
.highlight .si { color: #e6db74 }
.highlight .sx { color: #e6db74 }
.highlight .sr { color: #e6db74 }
.highlight .s1 { color: #e6db74 }
.highlight .ss { color: #e6db74 }
.highlight .bp { color: #f8f8f2 }
.highlight .fm { color: #a6e22e }
.highlight .vc { color: #f8f8f2 }
.highlight .vg { color: #f8f8f2 }
.highlight .vi { color: #f8f8f2 }
.highlight .vm { color: #f8f8f2 }
.highlight .il { color: #ae81ff }
@@ -1,0 +1,13 @@
@font-face {
font-family: 'Open Sans';
font-style: normal;
font-weight: 400;
src: local('Open Sans Regular'), local('OpenSans-Regular'),
url('./fonts/open-sans-v17-latin-regular.woff2') format('woff2'),
url('./fonts/open-sans-v17-latin-regular.woff') format('woff');
}
:root {
--typography__default: 'Open Sans', sans-serif;
}
@@ -1,0 +1,74 @@
const light = 'Light',
dark = 'Dark';
document.addEventListener("DOMContentLoaded", () => {
init();
});
const init = () => {
const darkSwitchesArray = document.querySelectorAll('.dark-light-switch');
darkSwitchesArray.forEach(darkSwitch => {
darkSwitch.innerHTML = getCookie('nightMode') ? light : dark;
darkSwitch.addEventListener('click', handleNightModeToggle);
});
checkCookie();
};
const checkCookie = () => {
if(getCookie('nightMode')) {
toggleDarkMode();
}
};
const handleNightModeToggle = () => {
if(getCookie('nightMode')) {
setCookie('nightMode', false, 365);
} else {
setCookie('nightMode', true, 365);
}
toggleDarkMode();
};
const toggleDarkMode = () => {
const darkSwitchesArray = document.querySelectorAll('.dark-light-switch');
darkSwitchesArray.forEach(darkSwitch => {
darkSwitch.innerHTML = getCookie('nightMode') ? light : dark;
});
document.body.classList.toggle('dark');
};
function setCookie(name,value,days) {
let expires = "";
if (days) {
let date = new Date();
date.setTime(date.getTime() + (days*24*60*60*1000));
expires = "; expires=" + date.toUTCString();
}
document.cookie = name + "=" + (value || "") + expires + "; path=/";
}
function getCookie(name) {
let nameEQ = name + "=";
let ca = document.cookie.split(';');
for(let i=0;i < ca.length;i++) {
let c = ca[i];
while (c.charAt(0) ===' ') c = c.substring(1,c.length);
if (c.indexOf(nameEQ) === 0) return c.substring(nameEQ.length,c.length);
}
return null;
}
let scrollPercent;
let scrollListener = () => {
let scrollTop = document.documentElement["scrollTop"] || document.body["scrollTop"];
let scrollBottom = (document.documentElement["scrollHeight"] ||
document.body["scrollHeight"]) - document.documentElement.clientHeight;
scrollPercent = scrollTop / scrollBottom * 100 + "%";
let progress = document.getElementById("_progress");
progress && progress.style.setProperty("--scroll", scrollPercent);
};
document.addEventListener("scroll", scrollListener, { passive: true });
@@ -1,0 +1,4 @@
---
---
@import 'main';
Binary files /dev/null and a/tmp/dark-mode.gif differ
Binary files /dev/null and a/tmp/perf-2.jpg differ
Binary files /dev/null and a/tmp/scroll-progress.gif differ
Binary files /dev/null and a/assets/fonts/open-sans-v17-latin-regular.woff differ
Binary files /dev/null and a/assets/fonts/open-sans-v17-latin-regular.woff2 differ