Tech

As you drive down the highway, you may notice an increasing number of hybrid and electric vehicles. Alternative energy automobiles are on the rise contributing to the global effort to reduce carbon emissions. As we move together down this road, researchers are looking to determine new solutions to this ongoing problem.

Dr. Muzammil Arshad, instructional assistant professor for the Department of Multidisciplinary Engineering at Texas A&M University, and a team of multidisciplinary student researchers conducted a study to analyze the performance of hydrogen-enriched fuel on spark engine performance and efficiency. This solution could make significant contributions to helping automobiles become more environmentally friendly.

"Due to climate change as well as a focus on reduced emissions and deprivation of fossil fuel reserves, there has been immense research to reduce emissions," said Arshad. "This has led to investigating effects of dual fuels on the emissions as well as engine performance parameters because we don't want to lose the combustion characteristics by injecting a secondary fuel."

Two multidisciplinary students, Jonathan Rodriguez and Miriam Alanis, contributed significantly and are co-authors of the research. As undergraduate students at the Higher Education Center at McAllen (HECM), this accomplishment is an impactful stepping stone.

Their research was accepted into the 12th U.S. Annual Combustion Meeting hosted in College Station, where they presented their findings.

"I think presenting at the conference was wonderful," said Alanis. "From the study, we were able to produce tangible results that could potentially be meaningful and useful."

This study was also recently published in the Petroleum and Chemical Industry International journal.

"These accolades establish our research and give it credibility," said Rodriguez. "We are making progress at the HECM. I believe we are part of the first student research project conducted on campus. As an undergraduate, I didn't believe it was an experience I would achieve until Dr. Arshad developed the project."

Spark ignition engines are commonly used in various small SUVs and sedans. In these engines, gasoline merges with air and is ignited by a spark formed by the spark plug, creating combustion. The car can convert thermal energy into kinetic by burning the fuel, allowing the car to move.

"We have performed numerical simulations to understand and predict the performance of spark ignition engines by introducing hydrogen in various quantities and predicting the effect on various efficiencies, in-cylinder pressure and emissions," said Arshad.

The goal is that by adding hydrogen, the car will be more fuel-efficient and produce less harmful emissions. The researchers also analyzed whether significant changes would be required to current spark ignition engines to account for the addition of hydrogen.

"Originally, we thought the difference in the in-cylinder pressure due to the enrichment could create issues that would require major modifications to the engine," said Rodriguez. "Our findings show a reduction in the in-cylinder peak pressure, consequently insinuating that we do not need major modifications to the engine to use this dual fuel. This research has potential value in the fuel market while leaving the vehicle market untouched."

As the first research initiative at the HECM, Arshad is thrilled with the results and plans to conduct similar projects with students in the future.

"Research experience and publications are a major skill they can now showcase on their resumes," said Arshad. "They also learned skills such as time management, working under pressure, meeting deadlines and presenting in front of large audiences. All of these skills are valuable and will help them in the future."

Engineers at Duke University have devised a system for manipulating particles approaching the miniscule 2.5 nanometer diameter of DNA using sound-induced electric fields. Dubbed "acoustoelectronic nanotweezers," the approach provides a label-free, dynamically controllable method of moving and trapping nanoparticles over a large area. The technology holds promise for applications in the fields ranging from condensed matter physics to biomedicine.

The research appears online on June 22 in Nature Communications.

Precisely controlling nanoparticles is a crucial ability for many emerging technologies. For example, separating exosomes and other tiny biological molecules from blood could lead to new types of diagnostic tests for the early detection of tumors and neurodegenerative diseases. Placing engineered nanoparticles in a specific pattern before fixing them in place can help create new types of materials with highly tunable properties.

For more than a decade, Tony Jun Huang, the William Bevan Distinguished Professor of Mechanical Engineering and Materials Science at Duke, has pursued acoustic tweezer systems that use sound waves to manipulate particles. However, it becomes difficult to push things around with sound when their profile drops below that of some of the smallest viruses.

"Although we're still fundamentally using sound, our acoustoelectronic nanotweezers use a very different mechanism than these previous technologies," said Joseph Rufo, a graduate student working in Huang's laboratory. "Now we're not only exploiting acoustic waves, but electric fields with the properties of acoustic waves."

Instead of using sound waves to directly move the nanoparticles, Huang, Rufo and Peiran Zhang, a postdoc in Huang's laboratory, use sound waves to create electric fields that provide the push. The new acoustoelectronic tweezer approach works by placing a piezoelectric substrate--a thin material that creates electricity in response to mechanical stress--beneath a small chamber filled with liquid. Four transducers are aligned on the chamber's sides, which send sound waves into the piezoelectric substrate.

These sound waves bounce around and interact with one another to create a stable pattern. And because the sound waves are creating stresses within the piezoelectric substrate, they also create electrical fields. These couple with the acoustic waves in a way that creates electric field patterns within the chamber above.

"The vibrations of the sound waves also make the electric field dynamically alternate between positive and negative charges," said Zhang. "This alternating electric field polarizes the nanoparticles in liquid, which serves as a handle to manipulate them."

The result is a mechanism that mixes some of the strengths of other nanoparticle manipulators. Because the acoustoelectronic nanotweezers induce an electromagnetic response in the nanomaterials, the nanoparticles do not need to be conductive on their own or tagged with any sort of modifier. And because the patterns are created with sound waves, their positions and properties can be quickly and easily modified to create a variety of options.

In the prototype, the researchers show nanoparticles placed into striped and checkerboard patterns. They even push individual particles around in an arbitrary manner dynamically, spelling out letters such as D, U, K and E. The researchers then demonstrate that these aligned nano-patterns can be transferred onto dry films using delicate nanoparticles such as carbon nanotubes, 3.5-nanometer proteins and 1.4-nanometer dextran often used in biomedical research. And they show that all of this can be accomplished on a working area that is tens to hundreds of times larger than current state-of-the-art nanotweezing technologies.

PULLMAN, Wash. - A tiny bee imposter, the syrphid fly, may be a big help to some gardens and farms, new research from Washington State University shows.

An observational study in Western Washington found that out of more than 2,400 pollinator visits to flowers at urban and rural farms about 35% of were made by flies--most of which were the black-and-yellow-striped syrphid flies, also called hover flies. For a few plants, including peas, kale and lilies, flies were the only pollinators observed. Overall, bees were still the most common, accounting for about 61% of floral visits, but the rest were made by other insects and spiders.

"We found that there really were a dramatic number of pollinators visiting flowers that were not bees," said Rae Olsson, a WSU post-doctoral fellow and lead author of the study published in Food Webs. "The majority of the non-bee pollinators were flies, and most of those were syrphid flies which is a group that commonly mimics bees."

Syrphid flies' bee-like colors probably help them avoid predators who are afraid of getting stung, but they are true flies with two wings as opposed to bees which have four. The flies might have additional benefits for plants, Olsson added, since as juveniles they eat pests like aphids. As adults, they consume nectar and visit flowers so have the potential to move pollen the same way that bees do, though it is less intentional than bees who collect pollen to feed their young.

For the study, the researchers surveyed plants and pollinating insects and spiders on 19 rural farms and 17 urban farms and gardens along the Interstate 5 corridor in Western Washington. They conducted surveys six separate times over two years. In addition to the visits by bees and syrphid flies, they also catalogued more rare visits by other arthropods including wasps, lacewings, spiders, butterflies, dragonflies, beetles and ants--all with visits of less than 4%.

Olsson first noticed the many different non-bee pollinators while working on a bee-survey project led by Elias Bloom, a recent WSU doctoral graduate. The results of this study underscore the need for researchers as well as gardeners and farmers to pay more attention to alternative pollinators, Olsson said, and hoped that similar studies would be conducted in other regions of the country.

"Bee populations are declining, and we are trying to help them, but there's room at the table for all the pollinators," Olsson said. "There are a lot of conservation and monitoring efforts for bees, but that doesn't extend to some of the other pollinators. I think people will be surprised to find that there are a lot more different types of pollinating insects - all we really need to do is to start paying a little more attention to them."

The study also noted pollinator differences between rural and urban spaces. Observations sites in urban areas showed a greater diversity of pollinators corresponding with the wider range of plants grown in city gardens and smaller-sized farms. Rural farms with their larger fields of plants had a greater abundance.

For every grower, urban or rural, who is interested in increasing the number and diversity of pollinators visiting their fields or gardens, Olsson recommended increasing the variety of flowering plants.

Making sure that something is flowering all throughout the season, even if on the edge of a field, will support the biodiversity of pollinators because their different life stages happen at different times of the year.

"Some pollinators like certain butterflies and moths are only present in a pollinating form for a small period of time," Olsson said. "They may only live for a few days as adults, so when they emerge and are ready to pollinate, it's good to make sure that you have something for them to eat."

For decades, governments and health authorities have tried to steer people away from "vice" products such as tobacco, soda and alcohol through counter-marketing measures -- things like tax increases, usage restrictions and ad campaigns.

But which ones are the most effective? And what do they mean for big brands such as Marlboro, Coca-Cola, McDonald's and Budweiser?

According to a new study from the UBC Sauder School of Business, they can all help people quit -- but how much they help, and who pays the price, varies significantly.

The researchers also found that tax hikes can disproportionately favour bigger brands, while tightened restrictions can hurt them.

For the study, titled Investigating the Effects of Excise Taxes, Public Usage Restrictions, and Antismoking Ads Across Cigarette Brands, researchers examined U.S. cigarette sales data from 2005 to 2010 and retail scanner data from 2006 to 2010. They also analyzed a comprehensive data set that comprised state-level cigarette taxes, state-level smoking restrictions and national anti-smoking advertising campaigns.

The team modeled each smoker's brand and purchase quantity, then looked at how the taxes, restrictions and ad campaigns influenced their decisions across different brands and price tiers.

What they found was that when taxes go up, big brands such as Marlboro may see an overall reduction in sales -- but they get a boost in market share over smaller players.

"Market leaders such as Marlboro were able to absorb more taxes and pass less cost down to their consumers," says UBC Sauder Assistant Professor Yanwen Wang (she, her, hers), who co-authored the study with Emory University Professor of Marketing Michael Lewis and New York University Professor of Marketing Vishal Singh. "So, when consumers look at the prices, it seems like Marlboro has raised prices less when compared to smaller brands."

Conversely, smoking restrictions seem to hit bigger brands harder -- likely because they take away smoking's brand-driven "cool" factor.

"Years ago, the Marlboro Man and Camel campaigns were really successful at creating that cool image -- so when you took a cigarette from the package, you created a social image," explains Professor Wang. "But if you're not allowed to smoke in public areas, it's taking away the channel for you to signal who you are through smoking -- and that reduces people's interest in smoking those higher equity brands."

The researchers also looked at the effect of anti-tobacco ads on large brands, but found their effect was neutral -- likely because most of the big campaigns and lawsuits happened years earlier, in the late 1990s and early 2000s.

The study also shows that while the taxes may help governments boost their bottom lines, ultimately smokers pay a heavier price. In fact, the researchers found that a 100 percent tax hike leads to a 30 percent increase in the rate of smokers quitting, but it puts the cost on consumers -- and only lifts overall tobacco tax revenue by roughly 28 percent because of declining sales.

"We don't speculate on whether it's right or not for consumers to bear the cost; that's a different debate," says Professor Wang. "But we want to highlight that tax increases bring disproportionate revenue to governments while putting an extra tax burden on smokers."

In contrast, strong smoking restrictions boost quit rates by nine percent and reduce tax revenues by six percent -- so while consumers may experience some inconvenience in terms of where they can smoke, they don't shoulder the economic costs.

Professor Wang says the findings could be helpful as governments and health authorities try to ween the public off other unhealthy products, including sugary sodas, fast food and alcohol. Earlier this year, B.C. announced a new tax that would affect vice products such as soft drinks and vape products; in May, Newfoundland and Labrador also announced tax hikes on sugary beverages and cigarettes.

The so-called sugar taxes will likely help curb consumption, says Professor Wang, but they will favour larger brands like Coca-Cola and Pepsi while hitting consumers in the pocketbook -- and governments may not get all the revenue they expect.

"Governments aren't going to get all of that extra money, and they need to understand it will impose a disproportionate economic burden on the consumers of soda drinks," says Professor Wang, who adds that because sugary drinks are so widely consumed, the taxes could disproportionately affect families, people with low incomes and people with disabilities.

"It's even harder to justify whether it's fair for everybody to bear the economic cost."

New research uncovers substantial differences in rates of childhood cancers when considering single year of age rather than grouping several years together. The study published by Wiley early online in CANCER, a peer-reviewed journal of the American Cancer Society, also found that minority children have different risks than white children for many types of cancer.

Cancer rates among children in the United States are typically reported in 5-year age groups, which may obscure important details. Also, racial and ethnic variations in pediatric cancer rates are typically presented in broad age categories.

Erin L. Marcotte, PhD, of the University of Minnesota, and her colleagues examined 2000-2017 data from the Surveillance, Epidemiology, and End Results (SEER) Program, a source for cancer statistics in the United States, to assess cancer incidence rates by narrow age groups from birth to 39 years and across races and ethnicities. "There are significant racial and ethnic disparities in the incidence of some childhood cancer types," said Dr. Marcotte. Additionally, unlike in cancers that occur in older adults, the incidence of cancer among children and young adults has striking variations by age at diagnosis, and studying these variations has often led to a deeper understanding of causes of childhood cancer."

Several cancer types showed substantial differences by single year of age, both overall and across racial and ethnic groups. Black children, adolescents and young adults had lower rates of acute lymphoblastic leukemia, or ALL (a white blood cell cancer), compared with white children, especially at ages 1 through 7 years and 16 through 20 years. "Black children and young adults had lower rates of ALL, the most common childhood leukemia, at every age, but this decreased risk was most striking among children ages 2 to 5, where the ALL incidence among Black children was less than half that of white children," said Dr. Marcotte.

The researchers also observed that while Black children experienced the same incidence of non-Hodgkin lymphoma (another white blood cell cancer) as white children, Black young adults were at higher risk than white young adults, beginning at age 28. Black children were also at higher risk for nephroblastoma, a rare kidney tumor typically diagnosed before age 5 years.

Hispanic children had higher risk of Hodgkin lymphoma than white children at ages 0 to 9 years, but had lower risk at all other ages. They also had lower rates of astrocytoma, a cancer of the brain or spinal cord, but higher rates of ALL, especially at ages 10 through 23 years. The analysis also revealed that Asian and Pacific Islanders and American Indian and Alaskan Natives have lower rates of many types of childhood cancer.

"Some of the patterns we observed may be due to racial and ethnic differences in known childhood cancer risk factors, such as exposure to infections and congenital anomalies," said Dr. Marcotte. "We also know that the causes of each type of childhood and young adult cancer may vary depending on the age at which it occurs. For instance, exposure to Epstein-Barr virus is associated with Hodgkin lymphoma diagnosed in children younger than age 10, but not at older ages. Thus Epstein-Barr virus exposure may explain the higher risk of Hodgkin lymphoma among Hispanic children younger than age 10."

Dr. Marcotte hopes that this work will play a role in reducing racial and ethnic disparities in cancer risk among children and young adults.

The most severe mass extinction event in the past 540 million years eliminated more than 90 percent of Earth's marine species and 75 percent of terrestrial species. Although scientists had previously hypothesized that the end-Permian mass extinction, which took place 251 million years ago, was triggered by voluminous volcanic eruptions in a region of what is now Siberia, they were not able to explain the mechanism by which the eruptions resulted in the extinction of so many different species, both in the oceans and on land.

Associate professor Laura Wasylenki of Northern Arizona University's School of Earth and Sustainability and Department of Chemistry and Biochemistry is co-author on a new paper in Nature Communications entitled, "Nickel isotopes link Siberian Traps aerosol particles to the end-Permian mass extinction," in collaboration with Chinese, Canadian and Swiss scientists. The paper presents the results of nickel isotope analyses performed in Wasylenki's lab on Late Permian sedimentary rocks collected in Arctic Canada. The samples have the lightest nickel isotope ratios ever measured in sedimentary rocks, and the only plausible explanation is that the nickel was sourced from the volcanic terrain, very likely carried by aerosol particles and deposited in the ocean, where it dramatically changed the chemistry of seawater and severely disrupted the marine ecosystem.

"The study results provide strong evidence that nickel-rich particles were aerosolized and dispersed widely, both through the atmosphere and into the ocean," Wasylenki said. "Nickel is an essential trace metal for many organisms, but an increase in nickel abundance would have driven an unusual surge in productivity of methanogens, microorganisms that produce methane gas. Increased methane would have been tremendously harmful to all oxygen-dependent life."

"Our data provide a direct link between global dispersion of Ni-rich aerosols, ocean chemistry changes and the mass extinction event," Wasylenki said. "The data also demonstrate that environmental degradation likely began well before the extinction event - perhaps starting as early as 300,000 years before then. Prior to this study, the connection between Siberian Traps flood basalt volcanism, marine anoxia and mass extinction was rather vague, but now we have evidence of a specific kill mechanism. This finding demonstrates the power of nickel isotope analyses, which are relatively new, to solve long-standing problems in the geosciences."

Wasylenki, who joined NAU in 2018, was formerly an igneous petrologist and then a specialist in calcite crystal growth and biomineralization. She now focuses on the use of metal stable isotope geochemistry to address geological, environmental and biological questions. Many of her recent and current projects have investigated metal isotope effects at solid-fluid interfaces, in particular during metal adsorption to oxyhydroxide mineral particles. This work has implications for ancient and modern geochemical cycles and environmental metal transport. Wasylenki's lab group, named Systematic Experimental Study and Analysis of Metals in the Environment (SESAME Lab), focuses on two main research themes, the cycling of transition metals in modern and ancient oceans and the environmental transport of toxic heavy metals.

A SARS-CoV-2 lateral flow test that combines two bacterial enzymes with genetic sequences and a couple of probes is cheaper and easier to use than PCR tests while producing comparably reliable results. Called Vigilant and designed at KAUST, the test can detect very small amounts of viral RNA in a sample.

"Several types of lateral flow tests are currently available or under research for detecting SARS-CoV-2," says KAUST Ph.D. student Tin Marsic. "Depending on how they work, they all have disadvantages, including detecting the virus only several days after infection or producing false positive and false negative results." PCR tests, which are conducted in laboratories, produce more reliable results but are expensive and require sophisticated equipment and skilled personnel.

"Vigilant can be conducted in nonlaboratory settings and is significantly cheaper and easier to use than PCR tests," says Marsic.

The first critical step of the Vigilant platform involves a technique called reverse transcription-recombinase polymerase amplification (RT-RPA) to make many copies of a specific region on the SARS-CoV-2 genome, if it exists in a person's nose and throat swab sample. PCR tests also amplify viral gene sequences in samples but involve putting the samples through multiple high and low temperature cycles. RT-RPA can be done at room temperature with much cheaper and easy-to-use equipment.

Any SARS-CoV-2 amplified genes in the product of this process are tagged with a molecule called biotin, then added to a test tube containing KAUST's specially designed detection complex.

This complex is formed of two enzymes. On one end, a bacterial enzyme called Cas9 is conjugated with an RNA guide that only recognizes and attaches to the corresponding SARS-CoV-2 gene sequence. On the other end, another bacterial enzyme called VirD2 is attached to a fluorescent-tagged nucleotide sequence.

Drops from the reaction between the complex and RT-RPA product are then added to a lateral flow test strip impregnated with a biotin-recognizing protein called streptavidin on one end and a fluorescent probe-recognizing antibody on the other. If the sample contains SARS-CoV-2 gene sequences, they will have bound to the VirD2-Cas9 complex. A positive result occurs when two visible lines appear. The first line is where biotin on the SARS-CoV-2 amplicon binds to streptavidin. The second line is where the fluorescent tag on the other end of the complex attaches to the strip's antibody. A negative result shows only as a single line caused by the fluorescent tag binding to the antibody.

"We're now working on making our Vigilant platform more user-friendly by coupling it with an even simpler amplification technique," says KAUST bioengineer Magdy Mahfouz, who led the research. "We are also working on producing other efficient and rapid diagnostic tests that can detect nucleic acids to enable point-of-care testing for pathogens, including viruses and disease markers."

Microalgae are "simple" organisms of single cells, yet they pack a mighty potential punch when it comes to helping humanity achieve carbon neutrality, according to researchers from the Qingdao Institute of Bioenergy and Bioprocess Technology (QIBEBT) of the Chinese Academy of Sciences (CAS). Their metabolic activities play fundamental roles in global carbon cycling and convert carbon dioxide into a wide variety of high-value macromolecules.

Now, the QIBEBT researchers have developed a way to rapidly determine exactly which microalgae -- out of the millions of variations -- can most readily convert carbon dioxide into valuable compounds that can be used for fuels, food and drugs. They published their approach on June 18 in Analytical Chemistry.

However, the current approach to identify microalgae and understand their metabolic activity involves culturing and studying each species. "It is slow and tedious," said first author Mohammadhadi Heidari Baladehi, a doctoral student in the Single-Cell Center and CAS Key Laboratory of Biofuels at QIBEBT. "Moreover, the vast majority of microalgae in nature are not yet cultured."

To speed up microalgae assessment, the researchers employed Raman Microspectroscopy, which produces images that reveal the metabolic activities of the cell.

In this work, Heidari Baladehi and his team established a database of "ramanomes" for microalgae, or collection of single-cell Raman spectra. The ramanome database consists of more than 9,000 cells from known, diverse microalgae species. To demonstrate the power of the database in rapid identification and functional characterization of microalgae, they applied a machine learning approach, meaning as more information was added to the system, the more the system learned to identify functional and genetic patterns between different organisms.

Heidari Baladehi said a critical strength of their approach was combining two Raman-based "portraits", one for pigments and one for all the other compounds in the cell. Most current approaches collect only one of the two portraits, and usually do not collect them from the same cell. The QIBEBT researchers proposed to combine the two portraits, so that a much more complete and richer range of information can be gleaned. With the combined portraits and the machine learning algorithm, their system can identify species and their metabolic functions with 97% accuracy, for those microalgae already cultured and recorded in database.

Furthermore, for those microalgal species that have not been cultured - they are abundant in the environment - the QIBEBT researchers invented a different strategy: the cells are imaged for both of the two Raman portraits to profile their metabolic functions first, and then sorted and sequenced for the genome sequences, one cell at a time. They achieved this using an instrument developed at Single-Cell Center called RACS-Seq. The instrument is unique in its ability to produce high-quality genome sequences for the target cell, at the resolution of precisely one cell, after collecting the Raman signal.

"This comprehensive approach for rapidly identifying and metabolically profiling single-cells, either cultured or uncultured, greatly accelerates the mining and screening of microalgal cell factories for carbon-neutral production," said XU Jian, Director of Single-Cell Center and a senior author of the study.

Based on their Microalgal Ramanome Database, the researchers have established an open-access web platform (http://mard.single-cell.cn/) to support the function-based ID system. They plan to further develop their database to accommodate other classes of living organisms on Earth.

Fragrances are functional molecules with a pleasant scent that are widely used in aqueous products (cosmetics and detergents) and on surfaces such as textiles, leather and wallpaper. However, maintaining gentle and continuous scent on these items is an ongoing challenge in the field of flavours and fragrances.

Profragrances are delivery systems used to control the release of the volatile compounds in fragrances. They have fragile chemical bonds that can be stimulated by ambient conditions such as light, temperature, pH value and even oxygen. Drawing on these molecular profragrances, several polymer-based capsulation technologies have been developed that not only control fragrance release, but enable the scale-up of profragrance fabrication. However, the thermodynamic method traditionally used in these technologies doesn't support tunable (controllable) particle size, resulting in uneven size distribution and poor reproducibility.

A study published in the KeAi journal Green Chemical Engineering, has introduced a new engineering strategy to construct photo- (or light-) controllable profragrance nanoparticles with the assistance of flash nanoprecipitation (FNP) technology. FNP uses commercial polymers to encapsulate photo-triggered profragrance in a hydrophobic core.

Co-corresponding author Wei-Hong Zhu, from the East China University of Science and Technology, explains: "Compared to conventional thermodynamic self-assembly methods, FNP-mediated profragrance nanoparticles can be tuned by varying experimental parameters. As a result, we were able to obtain profragrance nanoparticles which precisely control fragrance release, both in an aqueous solution and on wallpaper under indoor light. In addition, with this engineering strategy, the flash and scale-up preparation of profragrance nanoparticles can be easily realized for industrial applications, with high batch-to-batch reproducibility."

Carbon dioxide (CO2) emissions from human activities have risen drastically over the last century and a half and are seen as the primary cause of global warming and abnormal weather patterns. So, there has been considerable research focus, in a number of fields, on lowering our CO2 emissions and its atmospheric levels. One promising strategy is to chemically break down, or 'reduce,' CO2 using photocatalysts--compounds that absorb light energy and provide it to reactions, speeding them up. With this strategy, the solar powered reduction of CO2, where no other artificial source of energy is used, becomes possible, opening doors to a sustainable path to a sustainable future.

A team of scientists led by Drs. Shinji Kawasaki and Yosuke Ishii from Nagoya Institute of Technology, Japan, has been at the forefront of efforts to achieve efficient solar-energy-assisted CO2 reduction. Their recent breakthrough is published in Nature's Scientific Reports.

Their research began with the need to solve the limited applicability problem of silver iodate (AgIO3), a photocatalyst that has attracted considerable attention for being useful for the CO2 reduction reaction. The problem is that AgIO3 needs much higher energy than that which visible light can provide to function as an efficient photocatalyst; and visible light is the majority of solar radiation.

Scientists have attempted to work around this efficiency problem by combining AgIO3 with silver iodide (AgI), which can efficiently absorb and utilize visible light. However, AgIO3-AgI composites have complicated synthesis processes, making their large-scale manufacturing impractical. Further, they don't have structures that offer efficient pathways for the transfer of photoexcited electrons (electrons energized by light absorption) from AgI to AgIO3, which is key to the composite's catalytic activity.

"We have now developed a new photocatalyst that incorporates single-walled carbon nanotubes (SWCNTs) with AgIO3 and AgI to form a three-component composite catalyst," says Dr. Kawasaki, "The role of the SWCNTs is multimodal. It solves both the synthesis and the electron transfer pathway problems."

The three-component composite's synthesis process is simple and involves just two steps: 1. Encapsulating iodine molecules within the SWCNT using an electrochemical oxidation method; and 2. Preparing the composite by immersing the resultant of the previous step in an aqueous solution of silver nitrate (AgNO3).

Spectroscopic observations using the composite showed that during the synthesis process, the encapsulated iodine molecules received charge from the SWCNT and converted into specific ions. These then reacted with AgNO3 to form AgI and AgIO3 microcrystals, which, due to the initial positions of the encapsulated iodine molecules, were deposited on all the SWCNTs uniformly. Experimental analysis with simulated solar light revealed that the SWCNTs also acted as the conductive pathway through which photoexcited electrons moved from AgI to AgIO3, enabling the efficient reduction of CO2 to carbon monoxide (CO).

The incorporation of SWCNTs also allowed for the composite dispersion to be easily spray-coated on a thin film polymer to yield flexible photocatalytic electrodes that are versatile and can be used in various applications.

Dr. Ishii is hopeful about their photocatalyst's potential. "It can make the solar reduction of industrial CO2 emissions and atmospheric CO2 an easy-to-scale and sustainable renewable energy-based solution tackling global warming and climate change, making people's lives safer and healthier," he says.

The next step, the team says, is to explore the possibility of using their photocatalyst for solar hydrogen generation. Perhaps, humanity's future is bright after all!

Scientists have used a compound made from a starch derivative and baking soda to help convert mechanical to electrical energy. The approach, developed by scientists at Daegu Gyeongbuk Institute of Technology (DGIST), with colleagues in Korea and India, is cost-effective and biocompatible, and can help charge low-energy electronics like calculators and watches. The details were published in the journal Advanced Functional Materials.

"Triboelectric nanogenerators harvest mechanical energy and convert it into an electric current," explains DGIST robotics engineer Hoe Joon Kim. "But many of the materials used in these devices are considered a biohazard and are not suitable for wearable applications. Our triboelectric nanogenerator incorporates cyclodextrin, a green material that is widely used for drug delivery in the human body, making it eco-friendly and hazard-free."

Cyclodextrin is a polysaccharide compound produced from starch. The scientists used it to link sodium ions together in what is known as a metal-organic framework (MOF). MOFs form porous materials widely used in gas storage, catalysis and sensing.

Specifically, Kim and his team applied ultrasound to a mixture of cyclodextrin and sodium bicarbonate in water. They then added trimesic acid and applied another short round of ultrasound. The process happens at room temperature and leads to the formation of a MOF made of sodium ions linked together by cyclodextrin bonds.

The team incorporated the MOF into a nanogenerator by coating it onto a copper electrode, which sits on a plastic polyethylene terephthalate (PET) base. Opposite to the MOF layer is a Teflon layer placed on a second copper electrode that is also stuck to a PET sheet. The two sides of the nanogenerator open and close in response to movements, such as walking or jogging. Each time the MOF makes contact with the Teflon, electrons are exchanged and an electric current is generated. This process is called the triboelectric effect.

The team tested the device by attaching it to a shoe, a backpack, and a person's knee and abdomen. They found it could harvest mechanical energy from walking, jogging and bending, and even from some typical yoga moves. The device was able to drive low-power electronics like a digital wristwatch, a hydrometer and a calculator.

"Our MOF extends the list of triboelectric materials," says Kim. He and his team plan to continue looking for biocompatible materials that can be used in wearable applications. They are also working on developing super capacitors that can store energy generated from triboelectric nanogenerators. "Using the nanogenerator and super capacitor together, we believe we can develop next-generation energy systems for wearable electronics, biodevices and robots," he says.

The avian influenza, an acute viral infectious disease that occurs in poultry such as chickens, ducks, and migratory birds, has been reported to be transmittable to humans. It is difficult to control because it spreads among migratory birds that travel to China, Europe, and elsewhere. Once it is transmitted, it spreads rapidly. Disposing infected livestock is not only costly, but also a cause of serious environmental pollution. This is why vaccines against infectious diseases are imperative. To this, a research team in Korea has recently developed a plant-based, adjuvant-free, recombinant protein vaccine that exhibits a strong immune response.

Professor Inhwan Hwang and Ph.D. candidate Shi-Jian Song of the Department of Life Science at POSTECH - in joint research with Professor Chang Seon Song of Konkuk University, Professor Woe-Yeon Kim of Gyeongsang National University, and Eun-Ju Sohn of Bioapp, Inc. - have developed a multivalent vaccine against a variety of avian influenza viruses that does not require any adjuvant. This research was recently published in Journal of Integrative Plant Biology.

Infectious diseases in humans and animals caused by the influenza virus are occurring unpredictably around the world, seriously affecting human health and economic activities like the livestock industry. Various vaccines have been developed and used so far, but concerns have been raised regarding their safety. In particular, the recombinant vaccines enjoy high biosafety and specificity, but have the weakness of low immunogenicity and high production cost compared to inactivated virus or live attenuated virus vaccines.

To this, the joint research team focused on developing multivalent1 vaccines against various avian influenzas based on green vaccine technology. The researchers fabricated a protein trimer (tHA) using plant cells, just like making immune-stimulating drugs from antigenic spikes (haemagglutinin, HA) attached to the influenza virus. By coating this plant-produced tHA on the surface of the inactivated lactococcus without separation or purification, the researchers succeeded in producing bacteria-like particles (BLPs) that carry antigens.

BLPs (tHAs) developed this way showed strong immune responses in mice and chickens without adjuvants. In addition, injections of a bivalent vaccine with two different formulas2 even led to strong immune response to both antigens. This method shows promise to be produced quickly, economically and safely. In fact, the vaccines from this research were applied for patents and are being commercialized with the goal to advance into China and Southeast Asia, as it has gone through a technology transfer to BioApp Co., Ltd.

"Utilizing the green vaccine technology, we have developed a recombinant protein-based vaccine that is safe from exposure to the virus and more," explained Professor Inhwan Hwang of POSTECH who led the research. "Various strains appear at the same time for influenzas, and this multivalent vaccine can combat such strains."

This study was conducted with the support of the Ministry of Trade, Industry and Energy and the National Research Foundation of Korea.

Lead levels in London's atmosphere have dropped drastically since lead additives in petrol were phased out, and currently meet UK air quality targets. However despite this drop, airborne particles in London are still highly lead-enriched compared to natural background levels, according to new Imperial research published today in PNAS.

The study found that up to 40 per cent of lead in airborne particles today comes from the legacy of leaded petrol. The researchers say this highlights the long-term persistence of contaminants introduced by human activities in the environment.

Lead author of the study Dr Eléonore Resongles, who carried out the work at Imperial's Department of Earth Science and Engineering, said: "Petrol-derived lead deposited decades ago remains an important pollutant in London. Despite the leaded petrol ban, historically combusted lead is still present in London's air more than 20 years later."

The researchers compared the chemical and isotopic composition of particulate matter in the air with samples of road dust and urban soil, which confirmed the role of the resuspension of dust contaminated from leaded petrol in lead's persistence in London today.

They explained that lead from leaded petrol once settled in the environment and is steadily re-suspended into the air through wind and vehicle movement, providing a constant background level and remobilisation mechanism.

They say this also highlights a potential hazard that warrants further investigation into its effects on Londoners' health as, despite air quality targets, there is no 'safe' threshold for lead in humans.

Dr Resongles added: "Long-term low-level exposure to lead can adversely affect health and, while we don't yet know the health implications of our findings, they suggest that leaded petrol might still be providing low level exposure which can have detrimental effects on health."

Lead's legacy

Lead has historically been used in a variety of ways, from petrol, batteries, alloys and solders to piping and paint in homes and buildings - and until 1999, leaded petrol remained the primary source of lead emissions in the UK atmosphere. The use of lead in petrol has ceased in most countries worldwide because of evidence that exposure to lead causes neurodevelopmental problems in children and cardiovascular, kidney, and reproductive problems in adults.

The study, which included researchers from French National Research Institute for Sustainable Development and Princeton University in collaboration with University of Birmingham, German Meteorological Service, and King Abdulaziz University, measured the concentrations of lead and its isotopic composition in two London locations between 2014 and 2018, before comparing them with previous data from the 1960s, '70s, '90s, and 2010.

The researchers took eighteen samples of airborne particles at street level in Marylebone in the summer of 2018, and 20 samples on a 24-metre-high rooftop at Imperial's South Kensington campus between 2014 and 2018.

By comparing with historical data the isotopic composition of air particles in London, they found that lead sources have remained unchanged over the past decade. They also found that the isotope composition of the air particles was similar to the signature of soils and road dust, leading them to suggest that resuspension of lead-containing dust, perhaps with wind and vehicle movement, is now an important source of lead.

In the 1980s, annual average airborne lead concentrations in central London dropped from 500-600 ng/m3 of air to around 300 ng/m3, before dropping further to around 20 ng/m3 in 2000. The researchers in this study measured lead concentrations of 8 ng/m3 of air on average during the summer 2018 at Marylebone road.

Senior author Professor Dominik Weiss, also of Imperial's Department of Earth Science and Engineering, said: "We used to have a lot of lead circulating in the air, but it dropped dramatically when leaded petrol was phased out at the turn of the millennium. However, the evolution of isotope composition since then suggests that lead in the air, soil and dust persists at background levels, and this could turn out to be a concern for health.

"Our findings highlight the need for an in depth study of blood lead levels in the population as was done recently in the US. Legacy lead deposited pre-1999 is significantly contributing to the overall lead burden, so we must try to reduce further the amount of lead we are releasing today if we want to offset legacy metals.

"The findings from the London study are in line with results from similar studies we conducted in Sao Paolo, Brazil and raise questions about long-term lead contamination in other megacities worldwide."

The researchers say that if these current levels prove harmful, then measures should be taken to target the sources of the lead in soil and on roads.

Possible measures to lower lead levels include covering contaminated urban soils with fresh soil, which has been effective in reducing children's blood lead levels in New Orleans. Dr Resongles said: "Atmospheric lead has reached a baseline in London which is difficult to push down further with present policy measures. More research is needed to identify the effect of present air concentrations - even if they meet data air quality targets - on human health, and to find the best way to rid London of lead's legacy for good."

Holding onto everyday items as keepsakes when a loved one dies was as commonplace in prehistory as it is today, a new study suggests.

The study from the University of York suggests mundane items like spoons and grinding stones were kept by Iron Age people as an emotional reminder and a 'continuing bond' with the deceased - a practice which is replicated in societies across the globe today.

The research focused on "problematic stuff": everyday items used or owned by a deceased person that relatives might not want to reuse but which they are unable to simply throw away.

At the Scottish hillfort settlement of Broxmouth, dating from 640BC to AD210, everyday items like quernstones, used for grinding grain, and bone spoons found between roundhouse walls could have been placed there by loved ones as a means of maintaining a connection with the person who had died.

The study compared this with contemporary examples of similar behaviour, with the retention of relatives' clothing or worn-out shoes being particularly recurrent themes.

Dr Lindsey Büster from the Department of Archaeology said: "It is important to recognise the raw emotional power that everyday objects can acquire at certain times and places.

"Archaeologists have tended to focus on the high material value or the quantity of objects recovered and have interpreted these as deposited for safe keeping or gifts to the gods.

"My work uses archaeology to open up discussions around death, dying and bereavement in contemporary society, demonstrating that even the most mundane objects can take on special significance if they become tangible reminders of loved ones no longer physically with us."

The paper demonstrates that in many societies, everyday items might well be included in the grave with the dead. Traditional interpretations of grave goods have often seen them as necessary for accompanying the dead to the afterlife, but the easy disposal of "problematic stuff" - that is objects not needed or desired by living relatives but not appropriate for throwing out onto the rubbish heap - is another possible explanation.

Dr Büster added: "Archaeologists tend to caution against the transplanting of modern emotions onto past societies but I suggest that the universality of certain emotions does allow for the extrapolation of modern experiences onto the past, even if the specifics vary.

"I consider the experience of grief and bereavement to be one such emotion, even if the ways in which this was processed and navigated varies between individuals and societies. This research helps bring us a little closer to past individuals whose experience of life (and death), was in some ways, not so different from our own."

The paper, "'Problematic stuff': death, memory and the interpretation of cached objects" is published in Antiquity.

In a new publication from Opto-Electronic Advances; DOI https://doi.org/10.29026/oea.2021.200006, Researchers led by Professor Junsuk Rho from Pohang University of Science and Technology (POSTECH), South Korea consider switchable diurnal radiative cooling by doped VO2.

As the impacts of climate change are increasingly felt, thermoregulation technologies that do not consume external energy have attracted considerable attention in the field of energy-saving applications. Radiative cooling has received much research interest for its ability to cool an object even under direct solar illumination. Nanostructured materials, or multi-stacked layers, can be designed to control reflection and emission spectrum to block solar irradiance and/or to emit heat through the atmospheric window. However, one limitation of radiative cooling for static devices, is that the cooling also occurs in low temperature conditions such as in winter or at night when heating is desired instead. Thus, there has been a strong demand for researchers to develop smart, switchable radiative coolers that cool down objects when the temperature is high but can also heat up in low temperature conditions.

Phase change materials that have distinct phases in response to temperature have been considered good candidates for such requirements. A doped vanadium dioxide (VO2) has a transition temperature at room temperature; the temperature-dependent characteristics of VO2 can be used to design a radiative cooler that cools down at temperatures above the transition temperature while heating up otherwise, without requiring any energy. This passive, but switchable, radiative cooling can directly provide environmentally friendly thermoregulation technology as well as various other applications such as air conditioning and heating.

The authors of this article propose a switchable radiative cooler that satisfies the aforementioned conditions using VO2. They have designed a switchable emitter by stacking VO2 on an insulator-metal layer. The resultant tri-layer structure emits its heat to the atmosphere above the transition temperature. This emitter is combined with a solar reflector, that is composed of several one-dimensional photonic crystals, to form a switchable radiative cooler. Thus, the overall system can block heat from solar energy while emitting thermal energy to the atmosphere.

The authors demonstrated that the switchable radiative cooler maintains a moderate temperature resilient to environmental changes by simulating a cycle of temperature changes under real outdoor conditions. The cooler facilitates self-adaptive thermal control and thus can be implemented in practical applications such as cooling buildings and vehicles.