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Researchers discover self-assembling 2D and 3D materials

Self-assembly of matter is one of the fundamental principles of nature, directing the growth of larger ordered and functional systems from smaller building blocks. Self-assembly can be observed in all length scales from molecules to galaxies. Now, researchers at the Nanoscience Centre of the University of Jyväskylä and the HYBER Centre of Excellence of Aalto University in Finland report a novel discovery of self-assembling two- and three-dimensional materials that are formed by tiny gold nanoclusters of just a couple of nanometres in size, each having 102 gold atoms and a surface layer of 44 thiol molecules. The study, conducted with funding from the Academy of Finland and the European Research Council, has been published in Angewandte Chemie.

The atomic structure of the 102-atom gold nanocluster was first resolved by the group of Roger D Kornberg at Stanford University in 2007. Since then, several further studies of its properties have been conducted in the Jyväskylä Nanoscience Centre, where it has also been used for electron microscopy imaging of virus structures. The thiol surface of the nanocluster has a large number of acidic groups that can form directed hydrogen bonds to neighbouring nanoclusters and initiate directed self-assembly.

Read more.

Do you know anyone prone to pleonasm?

Read the full definition here: http://www.dictionary.com/wordoftheday/2016/11/16?param=social

Wanting to feel productive, the grad student prints multiple articles with reckless abandon.

The Science of Smog

On July 26, 1943, Los Angeles was blanketed by a thick gas that stung people’s eyes and blocked out the Sun. Panicked residents believed their city had been attacked using chemical warfare. But the cloud wasn’t an act of war. It was smog. A portmanteau of smoke and fog, the word smog was coined at the beginning of the 20th century to describe the thick gray haze that covered cities such as London, Glasgow, and Edinburgh.

This industrial smog was known to form when smoke from coal-burning home stoves and factories combined with moisture in the air. But the smog behind the LA panic was different. It was yellowish with a chemical odor. Since the city didn’t burn much coal, its cause would remain a mystery until a chemist named Arie Haagen-Smit identified two culprits, volatile organic compounds, or VOCs, and nitrous oxides. VOCs are compounds that easily become vapors and may contain elements, such as carbon, oxygen, hydrogen, chlorine, and sulfur. Some are naturally produced by plants and animals, but others come from manmade sources, like solvents, paints, glues, and petroleum. Meanwhile, the incomplete combustion of gas in motor vehicles  releases nitrous oxide. That’s what gives this type of smog its yellowish color.

VOCs and nitrous oxide react with sunlight to produce secondary pollutants called PANs and tropospheric, or ground level, ozone. PANs and ozone cause eye irritation and damage lung tissue. Both are key ingredients in photochemical smog, which is what had been plaguing LA. 

Smog isn’t just an aesthetic eyesore. The two forms of smog irritate the eyes, nose, and throat, exacerbate conditions like asthma and emphysema, and increase the risk of respiratory infections like bronchitis. Smog can be especially harmful to young children and older people and exposure in pregnant women has been linked to low birth weight and potential birth defects. Secondary pollutants found in photochemical smog can damage and weaken crops and decrease yield, making them more susceptible to insects.

After the Great Smog of London shut down all transportation in the city for days and caused more than 4,000 respiratory deaths, the Clean Air Act of 1956 banned burning coal in certain areas of the city, leading to a massive reduction in smog. Similarly, regulations on vehicle emissions and gas content in the US reduced the volatile compounds in the air and smog levels along with them. 

Smog remains a major problem around the world. Countries like China and Poland that depend on coal for energy experience high levels of industrial smog. Photochemical smog and airborne particles from vehicle emissions affect many rapidly developing cities, from Mexico City and Santiago to New Delhi and Tehran. Governments have tried many methods to tackle it, such as banning cars from driving for days at a time. As more than half of the world’s population crowds into cities, considering a shift to mass transit and away from fossil fuels may allow us to breathe easier.

From the TED-Ed Lesson The science of smog - Kim Preshoff

Animation by Juan M. Urbina Studios

Insecticides Mimic Melatonin, Creating Higher Risk of Diabetes

Synthetic chemicals commonly found in insecticides and garden products bind to the receptors that govern our biological clocks, University at Buffalo researchers have found. The research suggests that exposure to these insecticides adversely affects melatonin receptor signaling, creating a higher risk for metabolic diseases such as diabetes.

The research is in Chemical Research in Toxicology. (full access paywall)

Theodore Isaac Rubin, American Psychiatrist (via books-n-quotes)

Have you considered that if you don’t make waves, nobody including yourself will know that you are alive?

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Researchers identify method of creating long-lasting memories

Imagine if playing a new video game or riding a rollercoaster could help you prepare for an exam or remember other critical information.

A new study in mice shows this link may be possible.

Attention-grabbing experiences trigger the release of memory-enhancing chemicals. Those chemicals can etch memories into the brain that occur just before or soon after the experience, regardless of whether they were related to the event, according to researchers at UT Southwestern Medical Center’s Peter O’Donnell Jr. Brain Institute.

The findings, published in Nature, hold intriguing implications for methods of learning in classrooms as well as an array of potential uses in the workplace and personal life, researchers said.

The trick to creating long-lasting memories is to find something interesting enough to activate the release of dopamine from the brain’s locus coeruleus (LC) region.

“Activation of the locus coeruleus increases our memory of events that happen at the time of activation and may also increase the recall of those memories at a later time,” said Dr. Robert Greene, the study’s co-senior author and a Professor of Psychiatry and Neurosciences with the O’Donnell Brain Institute.

The study explains at the molecular level why people tend to remember certain events in their lives with particular clarity as well as unrelated details surrounding those events: for instance, what they were doing in the hours before the Sept. 11, 2001, terrorist attacks; or where they were when John F. Kennedy was assassinated.

“The degree to which these memories are enhanced probably has to do with the degree of activation of the LC,” said Dr. Greene, holder of the Sherry Gold Knopf Crasilneck Distinguished Chair in Psychiatry, in Honor of Mollie and Murray Gold, and the Sherry Knopf Crasilneck Distinguished Chair in Psychiatry, in Honor of Albert Knopf. “When the New York World Trade Center came down on 9/11, that was high activation.”

But life-changing events aren’t the only way to trigger the release of dopamine in this part of the brain. It could be as simple as a student playing a new video game during a quick break while studying for a crucial exam, or a company executive playing tennis right after trying to memorize a big speech.

“In general, anything that will grab your attention in a persistent kind of way can lead to activation,” Dr. Greene said.

Scientists have known dopamine plays a large role in memory enhancement, though where the chemical originates and how it’s triggered have been points of study over the years.

Dr. Greene led a study published in 2012 that identified the locus coeruleus as a third key source for dopamine in the brain, besides the ventral tegmental area and the substantia nigra. That research demonstrated the drug amphetamine could pharmacologically trigger the brain’s release of dopamine from the LC.

The latest study builds upon those findings, establishing that dopamine in this area of the brain can be naturally activated through behavioral actions and that these actions enhance memory retention.

The new study suggests that drugs targeting neurons in the locus coeruleus may affect learning and memory as well. The LC is located in the brain stem and has a range of functions that affect a person’s emotions, anxiety levels, sleep patterns, memory and other aspects of behavior.

The study tested 120 mice to establish a link between locus coeruleus neurons and neuronal circuits of the hippocampus – the region of the brain responsible for recording memories – that receive dopamine from the LC.

One part of the research involved putting the mice in an arena to search for food hidden in sand that changed location each day. The study found that mice that were given a “novel experience” – exploring an unfamiliar floor surface 30 minutes after being trained to remember the food location – did better in remembering where to find the food the next day.

Researchers correlated this memory enhancement to a molecular process in the brain by injecting the mice with a genetically encoded light-sensitive activator called channelrhodopsin. This sensor allowed them to selectively activate dopamine-carrying neurons of the locus coeruleus that go to the hippocampus and to see first-hand which neurons were responsible for the memory enhancement.

They found that selectively activating the channelrhodopsin-labeled neurons with blue light (a technique called optogenetics) could substitute for the novelty experience as a memory enhancer in mice. They also found that this activation could cause a direct, long-lasting synaptic strengthening – an enhancement of memory-relevant communication occurring at the junctions between neurons in the hippocampus. This process can mediate improvement of learning and memory.

Some next steps include investigating how big an impact this finding can have on human learning, whether it can eventually lead to an understanding of how patients can develop failing memories, and how to better target effective therapies for these patients, said Dr. Greene.

Major Research Instrumentation Program

Credit: Photo by Lance Long; courtesy Electronic Visualization Laboratory, University of Illinois at Chicago

The Major Research Instrumentation program has helped to fund pieces of research equipment ranging from scanning probe microscopes, which have helped to visualize and characterize nano-scale biological tools, to nuclear magnetic resonance (NMR) spectrometers, which allow chemists to identify the individual molecules they make. Not only does this instrumentation help scientists advance their own research, it’s also used to train the next generation of scientists. For example, an X-ray diffractometer at Utah State University allowed Joan Hevel and Sean Johnson to teach four high school students in their lab about protein crystallization. Learn more.