Conducted John P. Munafo, Jr., assistant professor of flavor science and natural products, and his graduate student, Trenton Kerley, the study “Changes in Tennessee Whiskey Odorants by the Lincoln County Process” was recently published in the Journal of Agricultural and Food Chemistry (JAFC).

The study incorporated a combination of advanced flavor chemistry techniques to probe the changes in flavor chemistry occurring during charcoal filtration. This type of filtration is a common step in the production of distilled beverages, including vodka and rum, but it’s a required step for a product to be labeled “Tennessee whiskey.” The step is called the Lincoln County Process (LCP), after the locale of the original Jack Daniel’s distillery. It is also referred to as “charcoal mellowing.”

The LCP step is performed by passing the fresh whiskey distillate through a bed of charcoal, usually derived from burnt sugar maple, prior to barrel-aging the product. Although no scientific studies have proved such a claim, it is believed that the LCP imparts a “smoother” flavor to Tennessee whiskey. In addition, by law for the distinction of having “Tennessee whiskey” on the label, the liquor must be produced in the state of Tennessee from at least 51% corn after having been aged in Tennessee for at least 2 years in unused charred oak barrels.

The actual LCP differs from distiller to distiller, and, as the details are generally held as a trade secret, the process has been historically shrouded in mystery. There are no regulations as to how the process is performed, only that the step is required. In other words, all a manufacturer needs to do is pass the distillate over charcoal (an undefined amount — possibly even just one piece). Thus, depending on how it’s conducted, the LCP step may not impact the whisky flavor at all. On the other hand, even small adjustments to the LCP can modify the flavor profile of the whiskey positively or negatively, potentially causing any number of surprises.

Munafo and Kerley describe how distillers adjust parameters empirically throughout the whiskey production process, then rely on professional tasters to sample products, blending subtly unique batches to achieve their target flavor. Munafo says, “By gaining a fundamental understanding of the changes in flavor chemistry occurring during whiskey production, our team could advise distillers about exactly what changes are needed to make their process produce their desired flavor goals. We want to give distillers levers to pull, so they are not randomly or blindly attempting to get the precise flavor they want.”

Samples used in the study were provided by the Sugarlands Distilling Company (SDC), in Gatlinburg, Tennessee, producers of the Roaming Man Whiskey. SDC invited the UTIA researchers to visit their distillery and collect in-process samples. Munafo says SDC prioritizes transparency around their craft and takes pride in sharing the research, discovery and distillation process of how their whiskey is made and what makes Tennessee whiskey unique.

Olfactory evaluations — the good ole smell test — revealed that the LCP treatment generally decreased malty, rancid, fatty and roasty aromas in the whiskey distillates. As for the odorants (i.e., molecules responsible for odor), 49 were identified in the distillate samples using an analytical technique called gas chromatography-olfactometry (GC-O). Nine of these odorants have never been reported in the scientific whiskey literature.

One of the newly found whiskey odorants, called DMPF, was originally discovered in cocoa. It is described as having a unique anise or citrus-like smell. Another of the newly discovered whiskey odorants (called MND) is described as having a pleasant dried hay-like aroma. Both odorants have remarkably low odor thresholds in the parts-per-trillion range, meaning that the smells can be detected at very low levels by people but are difficult to detect with scientific instrumentation.

The only previous investigation into how charcoal treatment affects whiskey was published in 1908 by William Dudley in the Journal of the American Chemical Society. The new study revealed fresh knowledge for optimizing Tennessee whiskey production. Thirty-one whiskey odorants were measured via a technique called stable isotope dilution assay (SIDA), all showing a decrease in concentration as a result of LCP treatment, albeit to different degrees. That is to say, while the LCP appears to be selective in removing certain odorants, the process didn’t increase or add any odorants to the distillate. This new knowledge can be used to optimize Tennessee whiskey production. For instance, the process can be optimized for the removal of undesirable aromas, while maintaining higher levels of desirable aromas, thus “tailoring” the flavor profile of the finished whiskey.

“We want to provide the analytical tools needed to help enable distillers to have more control of their processes and make more consistent and flavorful whiskey, says Dr. Munafo. “We want to help them to take out some of the guesswork involved in whiskey production.”

Additional studies are now underway at the UT Department of Food Science to characterize both the flavor chemistry of different types of whiskey and their production processes. The ultimate aim of the whiskey flavor chemistry program is to aid whiskey manufacturers in producing a consistent product with the exact flavor profile that they desire. Even with the aid of science Munafo says, “Whiskey making will ‘still’ remain an impressive art form.” Pun intended.

The researchers acknowledge support from the USDA National Institute of Food and Agriculture (NIFA) Hatch Project #1015002 and funding through the Food Science Department and start-up funding from the University of Tennessee Institute of Agriculture.

Writing in the Behavioural and Cognitive Psychotherapy Journal, the psychologists from the University of Bath highlight how health anxieties can be triggered by changes like returning to school and argue that young people need time to readjust to routine and to deal with emotions after such a prolonged period at home.

For some, they say, ongoing concerns about health, triggered by the invisible threat posed by COVID-19, could interfere with life and parents and teachers need to be aware of signs such as excessive hand washing, and reassurance-seeking about health-related worries.

Crucially not all children and young people will experience or develop health anxiety, and many have shown remarkable resilience in the face of an unprecedented health crisis. Yet for some, particularly those who are already vulnerable to worrying and anxiety, this year’s tumultuous events are likely to have significantly and negatively impacted them.

Dr Jo Daniels clinical psychologist within the Department of Psychology at the University of Bath, who throughout the pandemic has been active in advising and guiding individuals and organisations on responding to COVID-19-related health anxieties, explains: “Children are not immune to worries about their health, or the health of those around them. It is essential that we are able to recognise when normal concerns around covid become more problematic.

“Signs of stress in children may include tummy ache, sleeping problems and not engaging in normally enjoyable activities; for those particularly affected by health related anxiety, you might expect to see excessive hand-washing, exaggerated avoidance of touching objects for fear of picking up the virus, or repeated reassurance seeking from adults in addition to the usual signs of stress and worry.

“Children may not always be able to describe or verbalise their concerns clearly, so we are looking for marked changes in behaviour or worries that get in the way of living life to the full. Teachers also now have a role in this when children return back to school, as they tend to know the children well and school is where they will be spending a large part of their day.”

The team behind the study suggest health anxieties in children might be triggered by an immediate family member becoming ill, a shielding member of the household, or perhaps because of raised family tensions due to parental health-related worries. In these scenarios they advise parents and teachers to seek professional help where needed.

Their guidance offers suggestions about how cognitive behavioural therapy (CBT), including CBT conducted online or by phone, can be an effective treatment option to address children and young people’s health anxieties.

During the pandemic, the team have previously highlighted mental health vulnerabilities including health anxiety in adults, and loneliness in children and young people.

Dr Maria Loades, also from Bath’s Department of Psychology and who earlier this year published findings about the potential long-term mental health challenges for children and young people as a result of lockdown and loneliness, added: “As children and young people return to school, they need to have the opportunity to catch up, not just academically, but also socially and emotionally.

“A big part of this is having the time and space to connect with one another, through play, which gives them a chance to process the emotions and to share their experiences with others. It will take time for children and young people to adjust. While we want to avoid pathologizing normal responses to the pandemic, in children and young people especially, it is vital to spot the signs and intervene early.”

They recommend that parents or teachers who notice that a child or young person is worried about health should offer them the opportunity to talk about their worries by gently listening to their concerns, and then encouraging them to find ways to gradually face and overcome their fears.

Where a child or young person is seeking excessive reassurance from others, it’s important to remember that although this may help them in the short-term, it can keep their worries going over time. It is understandable to worry about health at this time and they say it is important to work with young people to find ways to resolve and understand their worries. Simple interventions that may be helpful could include correcting misunderstandings surrounding covid and the necessary precautions.

Although most will overcome their fears without specialist help, for some, their anxiety may get in the way of functioning and cause distress; in this instance, additional help should be sought via health care professionals or teachers.

Dr Loades adds: “We all need to work together to ensure children and young people are able to live their lives to the fullest.”

The results appear online on September 4 in the journal Nature Communications.

Thermoelectric materials convert heat into electricity when electrons migrate from the hot side of the material to the cold side. Because providing a temperature difference between its two sides is required, researchers are interested in trying to use these materials to generate electricity from the heat of a car’s tailpipe or recovering energy lost as heat in power plants.

Over the past couple of years, new records were set for thermoelectric efficiency with an emerging material called tin selenide and its sister compound, tin sulfide. The sulfide version is not quite as good a thermoelectric yet, but it is being optimized further because it is cheaper to produce and more environmentally friendly.

While scientists know that both of these compounds are excellent thermoelectric materials, they don’t exactly know why. In the new study, Olivier Delaire, associate professor of mechanical engineering and materials science at Duke, and two of his graduate students, Tyson Lanigan-Atkins and Shan Yang, tried to fill in a bit of that knowledge gap.

“We wanted to try to understand why these materials have such low thermal conductivity, which helps enable the strong thermoelectric properties they’re known for,” said Delaire. “Using a powerful combination of neutron scattering measurements and computer simulations, we discovered that it’s related to the material’s atomic vibrations at high temperature, which nobody had seen before.”

Low thermal conductivity is a necessary ingredient of any good thermoelectric material. Because electricity generation requires a heat differential between its two sides, it makes sense that materials that stop heat from spreading across them would perform well.

To get a view of tin sulfide’s atomic vibrations in action, Delaire and Lanigan-Atkins took samples to the High Flux Isotope Reactor at Oak Ridge National Laboratory. By ricocheting neutrons off of the tin sulfide’s atoms and detecting where they end up after, the researchers could determine where the atoms were and how they were collectively vibrating in the crystal’s lattice.

The facilities at ORNL were particularly well-suited for the task. Because the atomic vibrations of tin sulfide are relatively slow, the researchers need low-energy “cold” neutrons that are delicate enough to see them. And ORNL has some of the best cold-neutron instruments in the world.

“We found that the tin sulfide effectively has certain modes of vibration that are very ‘floppy,'” said Delaire. “And that its properties are connected with inherent instability in its crystal lattice.”

At lower temperatures, tin sulfide is a layered material with distorted grids of tin and sulfide lying on top of another, corrugated like an accordion. But at temperatures near its phase transition point of 980 degrees Fahrenheit — which is where thermoelectric generators often operate — that distorted environment begins to breaks down. The two layers, as if by magic, become undistorted again and more symmetric, which is where the “floppiness” comes into play.

Because the material is sloshing between the two structural arrangements at high temperature, its atoms no longer vibrate together like a well-tuned guitar string and instead become anharmonically damped. To understand this better, think of a car with terrible shocks as having a harmonic vibration — it will keep bouncing long after going over the slightest bump. But proper shocks will dampen that vibration, making it anharmonic and stopping it from oscillating for a long time.

“Heat waves travel through atomic vibrations in a material,” said Delaire. “So when the atomic vibrations in tin sulfide become floppy, they don’t transmit vibrations very quickly and they also don’t vibrate for very long. That’s the root cause of its ability to stop heat from traveling within it.”

With these results in hand, Delaire and Yang then sought to confirm and understand them computationally. Using supercomputers at Lawrence Berkeley National Laboratory, Yang was able to reproduce the same anharmonic effects at high temperatures. Besides confirming what they saw in the experiments, Delaire says these updated models will allow researchers to better search for new thermoelectric materials to use in tomorrow’s technologies.

“Researchers in the field have not been accounting for strong temperature dependences on heat propagation velocities, and this modeling shows just how important that variable can be,” said Delaire. “Adopting these results and other theoretical advances will make it easier for materials scientists to predict other good thermoelectric materials.”

Story Source:

Materials provided by Duke University. Original written by Ken Kingery. Note: Content may be edited for style and length.

The findings were published in the September 2, 2020 online issue of Neurology, the medical journal of the American Academy of Neurology.

Anticholinergic drugs are widely used for dozens of conditions, minor and major. Some of these medications require a prescription, while others can be purchased over the counter. They work by blocking acetylcholine — a type of neurotransmitter or chemical messenger known to be critical for memory function — from binding to receptors on certain nerve cells. The effect is to inhibit parasympathetic nerve impulses, which are involved in a variety of involuntary muscle movements, such as those in the gastrointestinal tract and lungs, and bodily functions like salivation, digestion and urination.

Researchers reported that cognitively normal study participants who were taking at least one anticholinergic drug at baseline were 47 percent more likely to develop mild cognitive impairment (MCI), often a precursor to dementia such as AD, while being tracked over a period of up to a decade compared to participants who did not take such drugs.

“This study, led by Alexandra Weigand, suggests that reducing anticholinergic drug use before cognitive problems appear may be important for preventing future negative effects on memory and thinking skills, especially for people at greater risk for Alzheimer’s disease,” said senior author Lisa Delano-Wood, PhD, associate professor in the Department of Psychiatry at UC San Diego School of Medicine. Weigand is a graduate student in the San Diego State University/University of California San Diego Joint Doctoral Program in Clinical Psychology.

Six hundred and eighty-eight adults were involved in the study, evenly divided by sex with an average age of 74. None of the participants displayed cognitive or memory problems at the beginning of the study. Each reported whether they were taking anticholinergic drugs. One-third were taking such medications, with an average of 4.7 anticholinergic drugs per person. Participants were given annual comprehensive cognitive tests for up to 10 years.

The scientists also looked at whether participants had biomarkers for AD in their cerebrospinal fluid, such as certain types of proteins, or a well-known genetic risk factor for AD. They found that participants with AD biomarkers who were taking anticholinergic drugs were four times more likely to develop MCI than persons lacking biomarkers and not taking the drugs.

Similarly, persons at genetic risk for AD who took anticholinergic drugs were approximately 2.5 times more likely to develop MCI than those without genetic risk factors and who were not taking the drugs.

“We believe this interaction between anticholinergic drugs and Alzheimer’s risk biomarkers acts in a ‘double hit’ manner,” said Weigand, the study’s first author. “In the first hit, Alzheimer’s biomarkers indicate that pathology has started to accumulate in and degenerate a small region called the basal forebrain that produces the chemical acetylcholine, which promotes thinking and memory. In the second hit, anticholinergic drugs further deplete the brain’s store of acetylcholine. This combined effect most significantly impacts a person’s thinking and memory.”

Study authors noted that, although older persons metabolize anticholinergic drugs differently than younger people, anticholinergic medications were being taken at levels much higher than the lowest effective dose recommended for older adults, with 57 percent taken at twice the recommended dosage and 18 percent at least four times the recommended dosage.

“This points to a potential area for improvement since reducing anticholinergic drug dosages may possibly delay cognitive decline,” said Weigand. “It’s important for older adults who take anticholinergic medications to regularly consult with their doctors and discuss medication use and dosages.”

Delano-Wood noted that more work is needed to examine brain and cognitive effects of anticholinergic medications and whether these medications accelerate age-related cognitive changes or directly lead to neurodegenerative disorders, such as AD. “Clinical ‘deprescribing’ studies are currently underway at certain research sites across the nation in an effort to investigate whether reducing or stopping use of these drugs does, in fact, lead to reductions in progressive cognitive impairment,” Delano-Wood said.

Co-authors include: Mark W. Bondi and Douglas R. Galasko, Veterans Affairs San Diego Healthcare System and UC San Diego; Kelsey R. Thomas, David P. Salmon, Daniel Sewell, James B. Brewer and Howard H. Feldman, UC San Diego; and Noll L. Campbell, Regenstrief Institute and Indiana University.

One proposed paradigm for shifting away from fossil fuels is the hydrogen economy, in which hydrogen gas powers society’s electrical needs. To mass produce hydrogen gas, some scientists are studying the process of splitting water — two hydrogen atoms and one oxygen atom — which would result in hydrogen fuel and breathable oxygen gas.

Feng Lin, an assistant professor of chemistry in the Virginia Tech College of Science, is focusing on energy storage and conversion research. This work is part of a new study published in the journal Nature Catalysis that solves a key, fundamental barrier in the electrochemical water splitting process where the Lin Lab demonstrates a new technique to reassemble, revivify, and reuse a catalyst that allows for energy-efficient water splitting. Chunguang Kuai, a former graduate student of Lin’s, is first author of the study with Lin and co-authors chemistry graduate students Zhengrui Xu, Anyang Hu, and Zhijie Yang.

The core idea of this study goes back to a subject in general chemistry classes: catalysts. These substances increase the rate of a reaction without being consumed in the chemical process. One way a catalyst increases the reaction rate is by decreasing the amount of energy needed for the reaction to commence.

Water may seem basic as a molecule made up of just three atoms, but the process of splitting it is quite difficult. But Lin’s lab has done so. Even moving one electron from a stable atom can be energy-intensive, but this reaction requires the transfer of four to oxidize oxygen to produce oxygen gas.

“In an electrochemical cell, the four-electron transfer process will make the reaction quite sluggish, and we need to have a higher electrochemical level to make it happen,” Lin said. “With a higher energy needed to split water, the long-term efficiency and catalyst stability become key challenges.”

In order to meet that high energy requirement, the Lin Lab introduces a common catalyst called mixed nickel iron hydroxide (MNF) to lower the threshold. Water splitting reactions with MNF work well, but due to the high reactivity of MNF, it has a short lifespan and the catalytic performance decreases quickly.

Lin and his team discovered a new technique that would allow for periodic reassembling to MNF’s original state, thus allowing the process of splitting water to continue. (The team used fresh water in their experiments, but Lin suggests salt water — the most abundant form of water on Earth — could work as well.)

MNF has a long history with energy studies. When Thomas Edison tinkered with batteries more than a century ago, he also used the same nickel and iron elements in nickel hydroxide-based batteries. Edison observed the formation of oxygen gas in his nickel hydroxide experiments, which is bad for a battery, but in the case of splitting water, production of oxygen gas is the goal.

“Scientists have realized for a long time that the addition of iron into the nickel hydroxide lattice is the key for the reactivity enhancement of water splitting.” Kuai said. “But under the catalytic conditions, the structure of the pre-designed MNF is highly dynamic due to the highly corrosive environment of the electrolytic solution.”

During Lin’s experiments, MNF degrades from a solid form into metal ions in the electrolytic solution — a key limitation to this process. But Lin’s team observed that when the electrochemical cell flips from the high, electrocatalytic potential to a low, reducing potential, just for a period of two minutes, the dissolved metal ions reassemble into the ideal MNF catalyst. This occurs due to a reversal of the pH gradient within the interface between the catalyst and the electrolytic solution.

“During the low potential for two minutes, we demonstrated we not only get nickel and iron ions deposited back into the electrode, but mixing them very well together and creating highly active catalytic sites,” Lin said. “This is truly exciting, because we rebuild the catalytic materials at the atomic length scale within a few nano-meter electrochemical interface.”

Another reason that the reformation works so well is that the Lin Lab synthesized novel MNF as thin sheets that are easier to reassemble than a bulk material.

Validating findings through X-rays

To corroborate these findings, Lin’s team conducted synchrotron X-ray measurements at the Advanced Photon Source of Argonne National Laboratory and at Stanford Synchrotron Radiation Lightsource of SLAC National Accelerator Laboratory. These measurements use the same basic premise as the common hospital X-ray but on a much larger scale.

“We wanted to observe what had happened during this entire process,” Kuai said. “We can use X-ray imaging to literally see the dissolution and redeposition of these metal irons to provide a fundamental picture of the chemical reactions.”

Synchrotron facilities require a massive loop, similar to the size of the Drillfield at Virginia Tech, that can perform X-ray spectroscopy and imaging at high speeds. This provides Lin high levels of data under the catalytic operating conditions. The study also provides insights into a range of other important electrochemical energy sciences, such as nitrogen reduction, carbon dioxide reduction, and zinc-air batteries.

“Beyond imaging, numerous X-ray spectroscopic measurements have allowed us to study how individual metal ions come together and form clusters with different chemical compositions,” Lin said. “This has really opened the door for probing electrochemical reactions in real chemical reaction environments.”

The work was supported by the Department of Chemistry startup funds and the Institute for Critical Technology and Applied Science.