Monthly Archives: July 2016

The chemistry of ice cream

Who doesn’t love ice cream?
Especially when the sun is shining! But what is the science that lies behind ice cream making? Have a look at this graphic which takes a look at some of the
ingredients that go into ice cream, and the important role they play in
creating the finished product.

Graphic: Compound Interest 
Before the development of modern
refrigeration, ice cream was a luxury reserved for special occasions. Making it
was quite laborious; ice was cut from lakes and ponds during the winter and
stored in holes in the ground, or in wood-frame or brick ice houses, insulated
by straw. Many farmers and plantation owners, including U.S. Presidents George
Washington and Thomas Jefferson, cut and stored ice in the winter for use in
the summer. Frederic Tudor of Boston turned ice harvesting and shipping into a
big business, cutting ice in New England and shipping it around the world.

Ice cream was made by hand in a
large bowl placed inside a tub filled with ice and salt. This was called the
pot-freezer method. French confectioners refined the pot-freezer method, making
ice cream in a sorbetière (a covered pail with a handle attached to the lid).
In the pot-freezer method, the temperature of the ingredients is reduced by the
mixture of crushed ice and salt. The salt water is cooled by the ice, and the
action of the salt on the ice causes it to (partially) melt, absorbing latent
heat and bringing the mixture below the freezing point of pure water. The
immersed container can also make better thermal contact with the salty water
and ice mixture than it could with ice alone.

The hand-cranked churn, which
also uses ice and salt for cooling, replaced the pot-freezer method. The exact
origin of the hand-cranked freezer is unknown, but the first U.S. patent for
one was #3254 issued to Nancy Johnson on 9 September 1843. The hand-cranked
churn produced smoother ice cream than the pot freezer and did it quicker. Many
inventors patented improvements on Johnson’s design.

In Europe and early America, ice
cream was made and sold by small businesses, mostly confectioners and caterers.
Jacob Fussell of Baltimore, Maryland was the first to manufacture ice cream on
a large scale. Fussell bought fresh dairy products from farmers in York County,
Pennsylvania, and sold them in Baltimore. An unstable demand for his dairy
products often left him with a surplus of cream, which he made into ice cream.
He built his first ice cream factory in Seven Valleys, Pennsylvania, in 1851.
Two years later, he moved his factory to Baltimore. Later, he opened factories
in several other cities and taught the business to others, who operated their
own plants. Mass production reduced the cost of ice cream and added to its

The development of industrial
refrigeration by German engineer Carl von Linde during the 1870s eliminated the
need to cut and store natural ice, and, when the continuous-process freezer was
perfected in 1926, commercial mass production of ice cream and the birth of the
modern ice cream industry was underway.

In modern times, a common method
for producing ice cream at home is to use an ice cream maker, an electrical
device that churns the ice cream mixture while cooled inside a household
freezer. Some more expensive models have an inbuilt freezing element. A newer method
is to add liquid nitrogen to the mixture while stirring it using a spoon or
spatula for a few seconds; a similar technique, advocated by Heston Blumenthal
as ideal for home cooks, is to add dry ice to the mixture while stirring for a
few minutes. Some ice cream recipes call for making a custard, folding in
whipped cream, and immediately freezing the mixture. Another method is to use a
pre-frozen solution of salt and water, which gradually melts as the ice cream

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Air pollution causes wrinkles and premature ageing, new research shows

Air pollution is prematurely ageing the faces of city
dwellers by accelerating wrinkles and age spots, according to emerging
scientific research.

The effects of toxic fumes on skin are being seen in both
western cities, such as London and New York, as well as in more visibly
polluted Asian cities and in some cases may be the primary cause of ageing. The
pollution is also being linked to worsening skin conditions such as eczema and

The scientific discoveries are now driving the world’s
biggest cosmetics companies to search for solutions, including medicine-like
compounds that directly block the biological damage. But doctors warn that some
common skin care routines, such as scrubs, make the damage from air pollution
even worse.

Poisonous air is already known to cause millions of early
deaths from lung and heart diseases and has been linked to diabetes and mental
health problems. But perhaps its most visible impact, the damage caused to
skin, is just beginning to be understood.

“With traffic pollution emerging as the single most toxic
substance for skin, the dream of perfect skin is over for those living and
working in traffic-polluted areas unless they take steps to protect their skin
right now,” said Dr Mervyn Patterson, a cosmetic doctor at Woodford Medical
clinics in the UK.

“Unless people do more they will end up wearing the
pollution on their faces in 10 years’ time. It is definitely something people
now need to take seriously.”

Nitrogen dioxide diffusion tube for air quality monitoring.By Etan J. Tal, via Wikimedia Commons.
Prof Jean Krutmann, director at the Leibniz Research
Institute for Environmental Medicine in Germany, said: “UV [damage from the
sun] was really the topic in skin protection for the last 20-30 years. Now I
think air pollution has the potential to keep us busy for the next few

Air pollution in urban areas, much of which comes from
traffic, includes tiny particles called PMs, nitrogen dioxide (NO2) and
chemicals such as polycyclic aromatic hydrocarbons (PAHs). “What is very clear
is that PMs are a problem for skin,” said Krutmann, whose work has shown PMs
increase age spots and wrinkles.

But one of the his newest studies showed NO2 also increases
ageing. They studied people in both Germany and China and discovered that age
spots on their cheeks increased by 25% with a relatively small increase in
pollution, 10 microgrammes of NO2 per cubic metre. Many parts of the UK have
illegally high levels of NO2, with London breaking its annual limit in the
first week of 2016, with levels reaching over 200 microgrammes of NO2 per cubic

Krutmann said other factors, such as UV exposure, nutrition
and smoking contribute to ageing: “But what we can say is that, at least for
the pigment spots on the cheeks, it seems air pollution is the major driver.”

“It is not a problem that is limited to China or India – we
have it in Paris, in London, wherever you have larger urban agglomerations you
have it,” he said. “In Europe everywhere is so densely populated and the
particles are being distributed by the wind, so it is very difficult to escape
from the problem.”

The accelerated skin ageing was seen in relatively young
people and Patterson said: “If you are seeing these changes in middle age,
these are worrying trends.”

Other recent research is summed up in a review paper in the
journal Frontiers in Environmental Science, which concluded: “Prolonged or
repetitive exposure to high levels of these [air] pollutants may have profound
negative effects on the skin.”

Understanding exactly how air pollution causes the skin
damage is at an early stage, according to Krutmann: “We are just now dipping
into the mechanisms.” But many of the pollutants are known to pass easily
through the skin and cause a variety of impacts.

“These agents have a very irritating effect and once they
get into the skin, they activate multiple pathways of inflammation,” said
Patterson. “Some pathways ignite the melanocytes, which create far too much
pigment and end up giving you unwanted sun spots.”

“Other pathways ignite messengers that make blood vessels
grow, that’s what results in increased redness and potentially rosacea,” he
said. “Also, if you damage skin, it goes into repair mode and excites enzymes
which re-adsorb damaged collagen. When you have too much chronic inflammation,
these enzymes remove more collagen than your skin can create. This produces
skin laxity and that’s where fine lines and wrinkles come in.”

Dr Debra Jaliman, a skin expert based in New York City, says
her patients are now worrying about the impact of air pollution on their skin,
which she said can cause darkening of the skin and acne-like eruptions, as well
as ageing.

“At the moment, there are not many products for prevention
[of air pollution damage], however it may be a trend in the coming years as it
becomes a much bigger issue,” she said.

Major beauty companies have begun their own research and are
launching the first products formulated to battle skin damage from toxic air.
Dr Frauke Neuser, senior scientist for Olay, a Procter and Gamble brand, has
run studies showing significantly lower skin hydration in people living in
polluted areas and lab studies showing that diesel fumes and PMs cause
inflammation in skin cells.

Her team then screened for ingredients that could counteract
some of the damaging effects. “We found niacinamide – vitamin B3 – to be
particularly effective,” she said. “We have recently increased its level in
several products by as much as 40%.”

Frauke’s work has also shown direct correlations between
spikes in PM air pollution in Beijing and an increase in hospital visits by
people with skin conditions including hives. “This indicates that not only skin
ageing but also skin health are affected by air pollution,” she said.

L’Oreal, another cosmetics giant, published a medical study
in 2015 showing that eczema and hives were more common in people in Mexico
exposed to higher levels of air pollution, a conclusion supported by separate
research in Canada. “The next step is to understand more deeply the
environment-induced damages, in order to develop skin ageing prevention
routines and products,” said Dr Steve Shiel, scientific director at L’Oreal.

Clinique, a big makeup brand, has already launched a sonic
face cleansing brush it claims better removes pollution. “This [air pollution] is
not going to go away. This is not a problem that is easily fixed,” said Janet
Pardo at Clinique.

However, researchers are now working on medicine-like
compounds that block the damage from air pollution from occurring in the first
place. Krutmann’s lab helped Symrise, one of the world’s biggest suppliers of
cosmetics ingredients, identify one, though the lab has no commercial stake in
the product, which is called SymUrban.

“We found one molecule that can do the job,” he said, and it
is now being registered as cosmetic ingredient. “In a few years from now I
expect we will see cosmetic products that can specifically protect against skin
ageing from air pollution.”

Patterson said it is possible for people to give themselves
some protection now. “You don’t have to sit back passively and put up with it.
You can take sensible, easy steps that will make a difference.”

“If your skin is really healthy, it is quite a good
barrier,” he said, explaining that the top layer is like a roof – flattened
cells like tiles separated by protective lipids.

“Certain skin care products are very disruptive to the
surface of the skin,” he warned. “So a darling of the industry is retinoids,
but these have a very profound negative effect on barrier function. Another
darling of the industry is glycolic acid, but it is also very disruptive to the
external skin barrier. People think these are good skin care, making the skin
look smoother, but they are not helpful for the overall health of the skin

Patterson is also dismissive of face scrubs: “The skin is
trying its damnedest to make this wonderful defence mechanism and what do women
and men do? They scrub the hell out of it. It just doesn’t make sense.” He said
products that help repair the skin barrier, by delivering the pre-cursor lipids
the cells need, are beneficial, as are ones that tackle inflammation.

“You can also put on a very nice physical shield in the form
of good quality mineral makeup,” he said. “That produces an effect like a
protective mesh and probably has some trapping effect, protecting against the
initial penetration of particles. But you also need always to try to remove
that shield in the evening, washing the slate clean every night.”

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New antidepressant target discovered

Northwestern Medicine scientists have shown how manipulating
a novel target in the brain using gene therapy could lead to new treatments for

The investigators showed decreasing a set of proteins called
HCN channels reduced depression-like behavior in mice. If replicated in humans,
the findings could inform fresh therapies for millions of patients who do not
respond to existing treatments for depression.

“Drugs currently available for treating depression help
most patients, but they stop working for some patients and don’t work from the
get-go for others,” said senior author Dr. Dane Chetkovich, a professor of
neurology and of physiology at Northwestern University Feinberg School of
Medicine and a Northwestern Medicine neurologist. “There is a real need
for new therapies to help patients desperate for alternatives to the available
therapeutic options.”

Drugs currently available for treating depression help most patients, but they don’t work for others.

Most existing antidepressants affect mood and emotions by
increasing levels of neurotransmitters called monoamines, namely serotonin,
dopamine and norepinephrine. But the fact that these drugs are not effective
for many patients suggests there are additional mechanisms underlying
depression yet to be uncovered that could be targeted with new therapies.

In previous research, Chetkovich’s lab and others showed
those mechanisms might involve the hippocampus, a region of the brain important
for learning, memory and emotional regulation. There, they saw changes to HCN
channels, typically involved in controlling the electrical activity of cells in
the heart and brain, also played a critical role in behaviors linked to

In the new study, a group of Northwestern scientists led by
Chetkovich took steps to translate that insight into a potential gene therapy
using mouse models. The scientists surgically injected mice with a nontoxic
virus engineered to express a gene that turns off HCN channel function in hippocampus

“When the HCN channels stopped working, the mice
behaved as if they’d been given antidepressant medications,” Chetkovich

In contrast, increasing the function of HCN channels removed
the antidepressant effect.

To measure depression-like behavior, the scientists measured
how long mice would seek to escape an environment before giving up – a test
commonly used by the pharmaceutical industry to screen compounds for
effectiveness as antidepressants, including medications currently on the

“This work not only identifies a totally new treatment
target for depression, it provides a detailed molecular description of the
structures that need to be manipulated for it to act as an antidepressant and
develops viral tools to do so,” said Chetkovich, who is also director of
Feinberg’s Medical Scientist Training Program.

In future research, the scientists are focusing on adapting
the viral gene therapy approach to human patients. They also have a grant from
the National Institute of Mental Health to find small molecules that could be
developed into oral medications to turn off HCN channels in the brain.

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EU referendum: UK science wakes up to new future

UK science will have to fight to
make sure it is not an after-thought as Britain renegotiates its relationship
with the EU, say research leaders.

The science establishment
expressed its “disappointment” on Friday with the referendum’s

It had been in the
“remain” camp.

How will UK science be affected by Brexit?
The decision to leave the EU now
means new structures will have to be put in place if the science sector is to
continue to enjoy favourable access to the union’s programmes and funding.

Jo Johnson, the minister for
universities and science – an “in” supporter – was one of the first
to react.

He took to Twitter in the early
hours to say: “Big decision. Let’s make it work.”

Britain’s science sector has done
increasingly well out of the EU in recent years, receiving €8.8bn in research
funding in 2007-2013 versus the €5.4bn it paid in over the same period. And
UK-based scientists have won about a fifth of all the grants, in terms of
value, from the top-tier programmes run by the European Research Council.

This funding flow-back has been
described as being akin to having another Research Council to go with the seven
national bodies that presently distribute UK government monies.

To maintain access to the EU
stream, Britain will likely now have to get itself some kind of
“associated country” status, similar to the positions held by other
non-EU countries such as Norway, Switzerland and Israel.

Associated countries pay a GDP
membership fee to “join the club”, after which, in principle, their
scientists can bid for support in the same way as those from full EU member

But the exact arrangements will
need to be worked out, and are going to depend on wider economic and political

Switzerland, for example, only
has “partial” associated status currently because it is not allowing
Croatian citizens free access to its labour market.

And having free movement to work
collaboratively is central to the way modern science is done.

Scientists for Britain is the
group of researchers that has most prominently lobbied for Brexit.

It has argued that the policies
of “political union” – and the regulations that flow from Brussels –
are not a prerequisite for the UK playing a full role in European scientific

The UK can survive and thrive
outside full union membership, it contends.

And on Friday, its spokesman Dr
Lee Upcraft said he was confident a new settlement would be found to maintain
UK involvement in EU programmes and by extension the country’s world-leading
position in European and global science.

But he also urged the research
establishment to hold government to account on 
national funding.

He echoed a recent complaint from
Stephen Hawking, that “we’ve become reliant on EU funding. We get back a
little more than we put in, and associated status will need to address this.
But the other thing we need to do, and what UK academia needs to do, is get
much better at lobbying government.”

EU funding had masked a
stagnation in national support, he told BBC News.

Dr Sarah Main from the neutral
Campaign for Science and Engineering said there would inevitably be a big
uncertainty factor going forward – which comes on top of sector changes already
being pushed through parliament in the form of the Higher Education and
Research bill (this will bring the seven Research Councils into a single body).

“In the run-up to the
referendum, people talked a lot about associated status,” she said.
“To what extent the EU will make a clear path to enable the UK to obtain
associated status and join science programmes back in the EU, I think will be
driven by the politics.

“You have to remember that
every associated country that people have quoted in the arguments up till now –
none was previously a member of the EU that then exited. So, it won’t
necessarily be straightforward, but it would be welcome because we do want to
compete in EU competitive funding streams, and as far as possible influence EU
regulations, markets and the conditions for doing science and the training of

Prof Venki Ramakrishnan, the
president of the Royal Society, agreed with Dr Main that ministers must not
lose sight of science as they renegotiate Britain’s relationship with the EU.

“In the upcoming
negotiations, we must make sure that research, which is the bedrock of a
sustainable economy, is not short-changed, and the government ensures that the
overall funding level of science is maintained,” he said in a statement.

Areas that should not be affected
directly by the Brexit vote include the big intergovernmental research

The likes of the European Space
agency; the European Southern Observatory, which operates major telescopes; and
Cern, which runs the Large Hadron Collider, the largest cryogenic facility in
the world at liquid helium temperature, are all separate legal entities to the

However, EU money has
increasingly been directed at some of their work. For example, Brussels is now
the largest single contributor to Esa’s budget, using the agency to procure the
Galileo satellite navigation system and the Copernicus/Sentinel Earth
observation constellation of satellites.

Britain’s science-related
companies working in these kinds of fields will want re-assurance that a
renegotiated future does not turn into a competitive disadvantage.

Patrick Wood is the managing
director of Surrey Satellite Technology Limited, which assembles the navigation
payloads for every Galileo spacecraft.

He told BBC News on Friday:
“We are days away from submitting the proposal for the next follow-on
order, to complete the Galileo constellation, and we will continue to work hard
with our supply chain to do this.

“I would look for our UK
politicians to unite together to continue to support this flagship European
project containing key UK technology, knowhow and to help protect jobs here in
the UK.”

Likewise, the chair of the House
of Commons Science and Technology committee, Nicola Blackwood MP, wanted to
highlight the care now needed to ensure the commercial science sector was
properly supported.

“My committee’s recent
report into EU regulation of the life sciences pointed out that this sector
alone comprises almost 5,000 companies employing 200,000 people in the UK,
generating an annual turnover of £60bn. The Science and Technology Committee
will want, in the coming weeks and months, to look at the consequences of this
vote for British science,” she said.

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