NEWS SHORTS

From the ACS Press Room Superheroes, Foods and Apps bring a Modern Twist to the Periodic Table

“Introducing Students to the Periodic Table Using a Descriptive Approach of Superheroes, Meats, and Fruits and Nuts”

Journal of Chemical Education

Many students, especially non-science majors, dread chemistry. The first lesson in an introductory chemistry course typically deals with how to interpret the periodic table of elements, but its complexity can be overwhelming to students with little or no previous exposure. Now, researchers reporting in ACS’ Journal of Chemical Education introduce an innovative way to make learning about the elements much more approachable — by using “pseudo” periodic tables filled with superheroes, foods and apps.

A fruit and nut pseudo periodic table was used to explain trends across and down the periodic table of elements. Credit: Adapted from Journal of Chemical Education 2020, DOI: 10.1021/acs.jchemed.0c01143

One of the fundamental topics taught in first -year undergraduate chemistry courses is the organization and layout of the periodic table

of elements. However, many university students consider it a daunting and difficult subject to master, prompting professors to seek new ways to engage their students and make its concepts more accessible. Previous educational studies presented the table in different formats, such as crossword puzzles and cartograms, to address multiple types of learning styles. Gregory Watson and colleagues reasoned that introducing the periodic table with familiar items could also help. And rather than teaching the full details right away, the researchers wanted to focus on some of its key characteristics first, using a contemporary, engaging and multi-level strategy. The team presented first-year chemistry students with a series of made-up, or pseudo, periodic tables with objects that they had likely encountered before, including fruits and nuts, superheroes, iPad apps and meats. The pseudo periodic versions replaced elements with single items to demonstrate one or more concepts needed to understand the trends and layout of the real chemical one. For example, a superhero table featured characters, such as Superman, Wonder Woman and the Green Lantern, prompting in -class discussions on how to group the icons by ability, strength, gender and other properties — just as the elements are arranged in the real periodic table based on their similarities. Over 75% of students taught with this strategy identified it as somewhat, very or extremely useful. An increase in correct an-

From the ACS Press Room Superheroes, Foods and

Apps, continued

swers relating to the subject on midterm exams suggested that these periodic tables improved students’ comprehension. The researchers say that the familiar items reduce stress and help students successfully build their base of chemistry knowledge. The authors do not acknowledge a funding source for this study .

2021 DFW Section Officers Chair: Trey Putnam Chair-elect: Mihaela C. Stefan Treasurer: Martha Gilchrist

Secretary: Heidi Conrad Councilors (2019-21): Linda Schultz, E. Thomas Strom, and Jason McAfee

Alternate Councilors (2019-21): Michael Bigwood, John McIlroy, and Daniela Hutanu

From the ACS Press Room

Single-dose COVID-19 Vaccine Triggers Antibody Response in Mice

“A Single Immunization with SpikeFunctionalized Ferritin Vaccines Elicits Neutralizing Antibody Responses against SARS-CoV-2 in Mice” ACS Central Science

Across the world, health care workers and high-risk groups are beginning to receive COVID-19 vaccines, offering hope for a return to normalcy amidst the pandemic. However, the vaccines authorized for emergency use in the U.S. require two doses to be effective, which can create problems with logistics and compliance. Now, researchers reporting in ACS Central Science have developed a nanoparticle vaccine that elicits a virusneutralizing antibody response in mice after only a single dose. The primary target for COVID-19 vaccines is the spike protein, which is necessary for SARS-CoV-2’s entry into cells. Both of the vaccines currently authorized in the U.S. are mRNA vaccines that cause human cells to temporarily produce the spike protein, triggering an immune response and antibody production. Peter Kim and colleagues wanted to try a different approach: a vaccine consisting of multiple copies of the spike protein displayed on ferritin nanoparticles. Ferritin is an iron storage protein found in many organisms that self-assembles into a larger nanoparticle. Other proteins, such as viral antigens, can be fused to ferritin so that each nanoparticle displays several copies of the protein, which might cause a stronger immune

response than a single copy. The researchers spliced spike protein and ferritin DNA together and then expressed the hybrid protein in cultured mammalian cells. The ferritin self-assembled into nanoparticles, each bearing eight copies of the spike protein trimer. The team purified the spike/ ferritin particles and injected them into mice. After a single immunization, mice produced neutralizing antibody titers that were at least two times higher than those in convalescent plasma from COVID-19 patients, and significantly higher than those in mice immunized with the spike protein alone. A second immunization 21 days later produced even higher antibody levels. Although these results must be confirmed in human clinical trials, they suggest that the spike/ferritin nanoparticles may be a viable strategy for single-dose vaccination against COVID-19, the researchers say. The authors acknowledge funding from the Stanford Maternal & Child Health Research Institute, the Damon Runyon Cancer Research Foundation, the National Institutes of Health, the Chan Zuckerberg Biohub, the Virginia and D. K. Ludwig Fund for Cancer Research and the Frank Quattrone and Denise Foderaro Family Research Fund.

From the ACS Press Room Spilling the Beans on Coffee’s True Identity

“Quantitative NMR Methodology for the Authentication of Roasted Coffee and Prediction of Blends”

Journal of Agricultural and Food Chemis-

try

People worldwide want their coffee to be both satisfying and reasonably priced. To meet these standards, roasters typically use a blend of two types of beans, arabica and robusta. But, some use more of the cheaper robusta than they acknowledge, as the bean composition is difficult to determine after roasting. Now, researchers reporting in ACS’

Journal of Agricultural and Food Chemis-

try have developed a new way to assess exactly what’s in that cup of joe. Coffee blends can have good quality and flavor. However, arabica beans are more desirable than other types, resulting in a higher market value for blends containing a higher proportion of this variety. In some cases, producers dilute their blends with the less expensive robusta beans, yet that is hard for consumers to discern. Recently, methods involving chromatography or spectroscopy were developed for coffee authentication, but most of these are laborand time-intensive, or use chloroform for the extraction, which limits the types of compounds that can be detected. In some studies, researchers used nuclear magnetic resonance

(NMR) spectroscopy to monitor the amount of 16-O-methylcafestol (16-OMC) in coffee, but its concentrations vary depending on geographic location and cultivar. So, Fabrice Berrué and colleagues wanted to build on their previous work with NMR to assess the chemical make-up of each coffee bean variety and confirm the blends of real samples. The researchers extracted compounds from a test set of pure coffee and known blends with methanol and identified the compounds with NMR. The team found 12 compounds with measurable concentrations, and two had significantly different amounts between the coffee varieties. Elevated concentrations of 16OMC were unique to robusta, while high concentrations of kahewol — a compound previously found in coffee beans by other researchers — were distinct in arabica. There was a direct, reproducible relationship between 16-OMC and kahewol concentrations found in the blends of the two varieties. The team then measured 16-OMC and kahewol levels, in addition to other flavor molecules, in 292 samples from producers around the world. They could successfully authenticate pure coffee, even with relatively low concentrations of the two indicator compounds. For samples in which the composition of blends was known, the team’s predictions were within 15% of the actual ratio. The new method results in a more robust and reliable way to verify unadulterated coffee and predict blends than previously reported approaches, the researchers say. The authors do not acknowledge a funding source for this study.

From the ACS Press Room

Detecting CRISPR/Cas Gene Doping

“First Steps toward Uncovering Gene Doping with CRISPR/Cas by Identifying SpCas9 in Plasma via HPLC–HRMS/MS”

Analytical Chemistry

All athletes want to be at the top of their game when they compete, but some resort to nefarious approaches to achieve peak muscle growth, speed and agility. Recent developments in gene editing technology could tempt athletes to change their DNA to get an edge. Now, researchers reporting in ACS’ Analytical Chemistry demonstrate first steps toward detecting this type of doping both in human plasma and in live mice. The gene editing method called CRISPR/ Cas is a popular way for scientists to precisely change the DNA in many organisms, and it recently gained even more attention when key developers of the method were awarded the 2020 Nobel Prize in Chemistry. With this method, researchers add an RNA molecule and a protein into cells. The RNA molecule guides the protein to the appropriate DNA sequence, and then the protein cuts DNA, like a pair of scissors, to allow alterations. Despite the ethical concerns that have been raised about the method’s potential application in humans, some athletes could ignore the risks and misuse it to alter their genes. Because CRISPR/Cas changes DNA, it is considered “gene doping” and is banned by the World Anti-Doping Agency, an independent international organization. A sufficient method to detect CRISPR/Cas gene editing needs to be developed, however. So, Mario Thevis and colleagues wanted to see whether they could identify the protein most likely to be used in this type of doping, Cas9 from the bacteria Streptococcus pyogenes (SpCas9), in human plasma samples and in mouse models. The team spiked the SpCas9 protein into human plasma, then isolated the protein and cut it into pieces. When the pieces were analyzed by mass spectrometry, the researchers found that they could successfully identify unique components of the SpCas9 protein from the complex plasma matrix. In another experiment, inactivated SpCas9, which can regulate gene expression without altering DNA, was spiked into human plasma samples. With a slight modification, the method allowed the team to purify and detect the inactive form. Finally, the team injected mice with SpCas9 and showed that their concentrations peaked in circulating blood after 2 hours and could be detected up to 8 hours after administration into muscle tissue. The researchers say that although much work still needs to be done, this is an initial step toward a test to pinpoint athletes trying to gain an unfair advantage. The authors acknowledge funding from the Manfred-Donike-Institute and the German Sport University.

From the ACS Press Room

‘Sniffing Out’ Fruity Thiols in Hoppy Beers

“Analysis of Hop-Derived Thiols in Beer Using On-Fiber Derivatization in Combination with HS-SPME and GC-MS/MS”

Journal of Agricultural and Food Chemistry

Hoppy beers such as pale ales are becoming increasingly popular. One reason is their pleasant fruity aroma that partially stems from compounds called thiols. Brewers have been looking for an accurate way to track thiols in beer, but current methods typically are not sensitive enough or require use of potentially harmful substances. Now, researchers in ACS’ Journal of Agricultural and Food Chemistry present an automated, solvent-less process to assess thiols at very low concentrations. Thiols, along with other compounds such as terpenes and esters, contribute to the enjoyable odors in “hop-forward” beer styles. Although very small amounts of thiols are present in beer, a little bit of these compounds goes a long way toward achieving a hoppy flavor and fruity aroma. Brewers would like more information about these volatile substances, but it’s challenging to accurately detect such small quantities. Previous studies have reported complex, multistep methods for thiol analysis in beer, but the approaches could not measure all of the thiols brewers want to know about, and some processes used harmful mercurycontaining compounds. Thiols also contribute to wine aromas, and researchers have used coated polymers that they can put into the air above the beverage to convert aerosolized wine thiols to more easily measureable compounds. The downside is that this method is not sensitive enough to measure the trace concentrations in beer. To develop a more robust analysis, Nils Rettberg and colleagues wanted to modify previous methods and come up with a safer, faster and more sensitive approach. In initial experiments to develop the new process, the team modified the sample preparation method used in wine analyses to convert aerosolized thiols to compounds with higher analytical sensitivity. Then, they tweaked and applied a tandem mass spectrometry approach to maximally detect and measure the resulting compounds. Finally, the team tested their new method on 13 commercially available beers from multiple countries made with hop varieties expected to have high thiol content. The distribution of thiols within the selected beers was consistent with prior studies. Surprisingly, the team could only detect one of the three expected thiols in a beer with real grapefruit added, suggesting that the fruit itself likely contributed scent compounds other than thi Continued on page 17

In Memoriam

Robert Hugh Neilson

JANUARY 24, 1948 – DECEMBER 17, 2020

Robert Hugh Neilson January 24, 1948 ¬ December 17, 2020 Robert Hugh Neilson (Bob) passed away on December 17, 2020 after a seven month battle with glioblastoma. Bob was born on January 24, 1948 and grew up in Pittsburgh, PA, where he was an active child who loved to play outside and was bored at school. He enjoyed challenging his mom, sister, and teachers, and he frequently recounted the story of his mother affectionately telling him to “go play in traffic”. As Bob grew older, his early boredom with school turned into a career in education and research. He attended Carnegie Mellon University where he majored in chemistry and was a part of the Army ROTC program. At Carnegie Mellon, he developed an appreciation for both main group chemistry and strong undergraduate teaching. Bob then went to Duke University where he earned his Ph.D. in chemistry working on boronnitrogen compounds. After Duke, Bob pursued post-doctoral research at the University of Texas at Austin, where he met Patty Wisian. Patty was attracted to Bob because he gave the best group meeting talks and had an amazing stereo system. Patty and Bob moved to Durham, NC where Bob returned to Duke for a temporary faculty position. They were married in the Duke chapel on January 24, 1976 in front a massive crowd of 12 of their closest family members. Bob began a strong research program at Duke, and it was here that his first graduate student initiated the groundbreaking work on silicon -nitrogen-phosphorus compounds. In 1978, Bob accepted a tenure track position in the Texas Christian University (TCU) Department of Chemistry. His research program in synthetic inorganic chemistry and inorganic polymers thrived with funding from agencies such as the Army Research Office (ARO) and the Office of Naval Research (ONR). Patty worked in his lab for a few years, and together they developed a novel class of polyphosphazenes that resulted in the first patents filed at TCU. At the same

time Bob and Patty started a family; in 1980 they welcomed their first child Andy. After a sabbatical in Boston, the family returned to Fort Worth, and in 1986 they welcomed their second child, Beth. Over his 42 years at TCU, Bob combined a successful research program with a passion for teaching. He challenged both students and colleagues to truly think and, with unwavering fairness, he held everyone to his high standards. In total, 22 Ph.D. students, 4 M.S. students, 18 postdocs, and countless undergraduates participated in his research program funded by agencies that included the Robert A. Welch Foundation, ONR, ARO, and the National

Science Foundation. His research produced over 100 peer-reviewed publications, and he was honored with the TCU Chancellor’s Award for Distinguished Research and Creative Activity in 1995 and the W. T. Doherty Award from American Chemical Society DFW Section in 2003. As his career progressed, his dedication to undergraduate education led to two nominations for the Dean’s teaching award. “Dr. Bob” taught general chemistry for decades to thousands of students, and he provided them all with a stern challenge and many life lessons. Bob was a man of few words but great impact, and his kindness, intelligence, and sense of humor were recognized by family, friends, and colleagues. As a dual-career family, he worked tirelessly cooking many meals and shuttling kids to school and activities. He enjoyed building and tinkering with computers and traveling with his family. Bob was a life-long fan of the Pittsburgh Steelers, Duke basketball, and PGA golf. Over the years, he and Patty traveled to Alaska in a Honda Fit, drove through southern Australia, attended the US Open twice, watched Duke Basketball at Cameron Indoor Stadium, went to Super Bowl XLV to see the Steelers, and more recently enjoyed TCU football and basketball games. Bob was preceded in death by his parents, Hugh and Evelyn Neilson, and his sister Beverly. He is survived by his wife Patty, children Andrew (Juanita) and Beth (John), and grandchildren McKayla, Evan, and Alice. A celebration of his life will be held at a later date when family, friends, and students can gather safely. In lieu of flowers, the family suggests donations in his memory to The Preston Robert Tisch Brain Tumor Center at Duke University (https:// tischbraintumorcenter.duke.edu/donate) or the Dr. Robert Neilson Chemistry Program Fund (https://advancement.tcu.edu/new/ makeagift/ then specify this fund) at TCU.

From the ACS Press Room ‘Sniffing Out’

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ols. The researchers say the method meets the requirements to detect thiols in beer, while also processing samples in a safer, simpler and quicker manner. The authors acknowledge funding from the German Federal Ministry for Economic Affairs and Energy.