Concrete, asphalt, glass, electronic chips: sand has many applications. Composed of small mineral particles, this granular material comes from sensitive dynamic environments such as seas, beaches, lakes and rivers or, from static land-based environments such as ancient river deposits and rock quarries. It is estimated that 50 billion tons of sand are used each year. Over the past two decades demand has tripled primarily due to urbanisation and population growth, a trend which is expected to continue with aggregates use reaching beyond 50 Bt per year by 2030.

In addition to the risks of local shortages, the extraction of such a volume of sand has environmental and societal consequences. For example, it is leading to erosion in river banks, which significantly increases the risk of flooding. In some countries, sand mining has caused loss of livelihoods in communities.

Two sustainability challenges with one solution

Researchers from the University of Geneva (UNIGE) and from the Sustainable Minerals Institute at the University of Queensland (UQ), Australia, have researched the potential of a viable alternative to naturally occurring sand. This material, presented in a recent report published by the two universities, has been coined ”ore-sand”.

UNIGE’s Adjunct Professor at Department F.-A. Forel for environmental and aquatic sciences of the Faculty of Science, Pascal Peduzzi said that “ore-sand has the largest potential in volume for reducing the amount of sand taken in the natural environment. By using what has been so far considered as ”left over” material, the project gives an important impetus towards a more circular economy.”

The production of ore-sand can help reduce the production of mineral mining waste and thus the further build-up of mine tailings. Mineral wastes from the mining of ores currently represents the largest waste stream on the planet, estimated between 30-60 billion tonnes per year. These residues come from crushing operations to extract certain metals from the rock.

SMI’s Development Minerals Program Leader Professor Daniel Franks said ore-sand has the potential to address two global sustainability challenges simultaneously. “Separating and repurposing these sand-like materials before they are added to the waste stream would not only significantly reduce the volume of waste being generated but could also create a responsible source of sand.”

Reduction of carbon emissions

The 12-month study independently sampled and investigated sand produced from iron ore mining, pioneered by Vale S.A in Brazil, which has previously experienced tailings dam failures. After an analysis of the chemical properties and some refining operations, the researchers were able to demonstrate that part of the material stream which would otherwise end up as mining residues could be used as a substitute for construction and industrial sand, in the same way as recycled concrete and steel slag. “If these results can be replicated with other types of mineral ores there is potential for major reductions in global mine tailings.”

“By mapping mining locations worldwide and modelling global sand consumption, we discovered that almost a third of mine sites can find at least some demand for ore-sand within a 50 km range. This could contribute to at least 10% reduction in the volume of tailings generation at each site. Simultaneously, almost half of the global sand market (by volume) could find a local source of ore-sand. For example, ore-sand could potentially substitute 1 billion metric tons of sand demand in China,” explains Daniel Franks.

In addition, the life cycle assessment of ore-sand, based on the Vale case, shows that substituting naturally sourced sand with ore-sand could potentially lead to net reductions in carbon emissions during sand production. The carbon emissions by transport is however a key consideration.

A benefit for mining companies

“Considering the co-production of ore-sand is a significant advantage for mining companies: it reduces the large tailings which hinder operational mining activities, while at the same time can generate additional revenues. Ore-sand is a step towards a “no tailings mine”, explains Pascal Peduzzi. Developing countries have fewer options for using recycled aggregate materials, given their more recent infrastructure. However, many have mining operations that can generate ore-sand as a by-product.”

Some of the next steps are to collaborate with aggregate market players to demonstrate this substitute material’s ease-of-use, performance and sourcing process. Findings from the study were presented at the 5th United Nations Environment Assembly. A new UNEA resolution (UNEP/EA5/L18/REV.1) on ”Environmental aspects of minerals and metals management” calls for strengthened scientific, technical and policy knowledge with regard to sand to support global policies and action regarding its environmentally sound extraction and use.

Citation: Golev, A., Gallagher, L., Vander Velpen, A., Lynggaard, J.R., Friot, D., Stringer, M., Chuah, S., Arbelaez-Ruiz, D., Mazzinghy, D., Moura, L., Peduzzi, P., Franks, D.M. (2022). Ore-sand: A potential new solution to the mine tailings and global sand sustainability crises. Final Report. Version 1.4 (March 2022). The University of Queensland & University of Geneva.

As the ever-evolving SARS-CoV-2 virus begins to evade once promising treatments, such as monoclonal antibody therapies, researchers have become more interested in these “decoy” nanoparticles. Mimicking regular cells, decoy nanoparticles soak up viruses like a sponge, inhibiting them from infecting the rest of the body.

In a new study, Northwestern University synthetic biologists set out to elucidate the design rules needed make decoy nanoparticles effective and resistant to viral escape. After designing and testing various iterations, the researchers identified a broad set of decoys — all manufacturable using different methods — that were incredibly effective against the original virus as well as mutant variants.

In fact, decoy nanoparticles were up to 50 times more effective at inhibiting naturally occurring viral mutants, compared to traditional, protein-based inhibitor drugs. When tested against a viral mutant designed to resist such treatments, decoy nanoparticles were up to 1,500 times more effective at inhibiting infection.

Although much more research and clinical evaluations are needed, the researchers believe decoy nanoparticle infusions someday could potentially be used to treat patients with severe or prolonged viral infections.

The study was published late last week (April 7) in the journal Small. In the paper, the team tested decoy nanoparticles against the parent SARS-CoV-2 virus and five variants (including beta, delta, delta-plus and lambda) in a cellular culture.

“We showed that decoy nanoparticles are effective inhibitors of all these different viral variants,” said Northwestern’s Joshua Leonard, co-senior author of the study. “Even variants that escape other drugs did not escape our decoy nanoparticles.”

“As we were conducting the study, different variants kept popping up around the world,” added Northwestern’s Neha Kamat, co-senior author of the study. “We kept testing our decoys against the new variants, and they just kept working. It’s very effective.”

Leonard is an associate professor of chemical and biological engineering in Northwestern’s McCormick School of Engineering. Kamat is an assistant professor of biomedical engineering in McCormick. Both are key members of Northwestern’s Center for Synthetic Biology.

‘Evolutionary rock and a hard place’

As the SARS-CoV-2 virus has mutated to create new variants, some treatments have become less effective in fighting the ever-evolving virus. Just last month, the U.S. Food and Drug Administration (FDA) paused several monoclonal antibody treatments, for example, due to their failure against the BA.2 omicron subvariant.

But even where treatments fail, the decoy nanoparticles in the new study never lost effectiveness. Leonard said this is because the decoys put SARS-CoV-2 “between an evolutionary rock and a hard place.”

SARS-CoV-2 infects human cells by binding its infamous spike protein to the human angiotensin-converting enzyme 2 (ACE2) receptor. A protein on the surface of cells, ACE2 provides an entry point for the virus.

To design decoy nanoparticles, the Northwestern team used nanosized particles (extracellular vesicles) naturally released from all cell types. They engineered cells producing these particles to overexpress the gene for ACE2, leading to many ACE2 receptors on the particles’ surfaces. When the virus came into contact with the decoy, it bonded tightly to these receptors rather than to real cells, rendering the virus unable to infect cells.

“For the virus to get into a cell, it has to bind to the ACE2 receptor,” Leonard said. “Decoy nanoparticles present an evolutionary challenge for SARS-CoV-2. The virus would have to come up with an entirely different way to enter cells in order to avoid the need to use ACE2 receptors. There is no obvious evolutionary escape route.”

Future benefits

In addition to being effective against drug-resistant viruses, decoy nanoparticles come with several other benefits. Because they are biological (rather than synthetic) materials, the nanoparticles are less likely to elicit an immune response, which causes inflammation and can interfere with the drug’s efficacy. They also exhibit low toxicity, making them particularly well-suited for use in sustained or repeated administration for treating severely ill patients.

When the COVID-19 pandemic began, researchers and clinicians experienced an unnerving gap between discovering the virus and developing new drugs to treat it. For the next pandemic, decoy nanoparticles could provide a quick, effective treatment before vaccines are developed.

“The decoy strategy is one of the most immediate things you can try,” Leonard said. “As soon as you know the receptor that the virus uses, you can start building decoy particles with those receptors. We could potentially fast-track an approach like this to reduce severe illness and death in the crucial early stages of future viral pandemics.”

The study, “Elucidating design principles for engineering cell-derived vesicles to inhibit SARS-CoV-2 infection,” was supported by the National Science Foundation (grant numbers 1844219 and 1844336) and a gift from Kairos Ventures.

Study results also pave the way for new potential therapeutic targets to rejuvenate the immune system in older adults and thereby reduce their risk of infectious disease.

“Through this study, we have gained a new understanding of why older adults are more susceptible to infectious diseases, which will enable us to identify potential new treatments,” said senior author Michael Demetriou, MD, PhD, a professor of neurology at the UCI School of Medicine and chief of the Division of Multiple Sclerosis and Neuroimmunology at UCI. First author and assistant professor in the UCI Department of Pathology, Haik Mkhikian, MD, PhD, added, “We’ve identified a potential fountain of youth for the immune system.”

The study, titled, “Age-associated impairment of T cell immunity is linked to sex-dimorphic elevation of N-glycan branching,” was published in Nature Aging.

T cell immunity declines with aging, thereby increasing severity and mortality from infectious disease. T cells are the quarterback of the immune system and coordinate immune responses to fight off infections. The addition of complex and branched carbohydrate chains (‘glycans’) to proteins suppresses T cells function.

In this study, researchers show that the branched glycans increase with age in T cells from females more than in males due to age-associated increases in an important sugar metabolite (N-acetylglucosamine) and signaling by the T cell cytokine interleukin-7.

“Our research reveals that reversing the elevation in branched glycans rejuvenates human and mouse T cell function and reduces severity of Salmonella infection in old female mice,” said Demetriou.

Mkhikian added, “This suggests several potential novel therapeutic targets to revitalize old T cells, such as altering branched glycans or the age-triggered elevation in serum N-acetylglucosamine and IL-7 signaling.”

Aging-associated immune dysfunction, referred to as immunosenescence, contributes to increased morbidity and mortality from both infectious and neoplastic diseases in adults aged 65 years and older. In the U.S, for example, around 89 percent of annual deaths from influenza are in people at least 65?years old, despite this age group representing only around 15 percent of the nation’s population. More recently, the vulnerability of older adults to viral infections has been tragically highlighted by the recent emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Increased morbidity and mortality in older adults also occurs with common bacterial infections such as those caused by the enteric pathogen Salmonella. Furthermore, efficacy of immunizations declines with age, further increasing risk of infection in older adults. The rapidly aging population in the developed world exacerbates this issue and heightens the need for interventions that effectively target immunosenescence.

Previous studies examined transcriptome changes in highly purified aged T cell subsets. In this study, researchers analyzed T cell populations by age and sex, with results suggesting sex-specific differences that imply that effective interventions to reverse immune dysfunction in older adults may require sex-specific strategies.

The study was supported by funding from the National Institute of Allergy and Infectious Disease, the National Center for Complementary and Integrative health, The Burroughs Wellcome Fund and a predoctoral fellowship from the American heart Association.

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Warming winters may sound like a welcome change for some farmers because the change in temperature could reduce freezing stress on plants and create more ideal conditions for growing overwinter cash crops and winter cover crops. However, when looking at climate change from a cross-seasonal perspective and accounting for declining snowpack, researchers are finding that the whole picture isn’t so sunny.

Reduced snow may result in more exposure of winter crops to freeze and could mean greater risks for agricultural drought.

In a new study published in Nature Climate Change, Zhenong Jin, Ph.D., an assistant professor in the Department of Bioproducts and Biosystems Engineering at the University of Minnesota, led an international team in researching the implications that could be associated with warmer winters and declining snowpack, using winter wheat (the largest winter crop in the U.S.) as an example.

“Although the implications of changes in snow for agricultural irrigation are beginning to be understood, the consequences of such for predominantly rainfed winter crops such as winter wheat remain largely unknown. There might be risks for being overoptimistic about growing overwinter crops under climate change,” said Jin.

Researchers used panel regression, a powerful statistical method to analyze repeated observations over time, to attribute the interannual variability of winter wheat yield to multiple interactive environmental factors. These factors included cold season freezing degree days, growing degree days, rainfall and snowfall during the growing season and snow cover fraction during frozen days.

The researchers found:

• From 1999-2019, snow cover insulation weakened yield losses due to freezing stress by 22%.
• Projections show that future reduced snow cover could offset up to one-third of the yield benefit from reduced frost.

“Our study highlighted the potential freezing risk in winters with decreased snow cover, especially when seedlings were exposed to comparatively warmer conditions that caused loss of winter-hardiness, which can cause significant yield losses of winter crops,” said Peng Zhu, Ph.D., a Researcher from the Climate and Environment Sciences Laboratory of the Pierre Simon Laplace Institute, who co-led this study.

This research will help inform breeders as they consider the complex tradeoffs among warming, reduced snowpack and occasional freezing threats when developing climate-smart cultivars.

These results also highlight the necessity of improving the representation of snow associated processes in crop models to better evaluate climate change effects and adaptation potential in cropping systems.

“It is worth noting that in some cropping systems freezing stress is appreciated, since it helps farmers control pests and diseases and snow is even removed or at least made more compact by farmers to increase the freezing of the soil,” said Jin. “When data becomes available, future studies might also need to account for the influence of snow on pests and diseases to comprehensively understand what future changes in snowpack mean for the cropping system.”

Funding for this research was partially supported by the USDA National Institute of Food and Agriculture (NIFA) and the French National Research Agency.

Other members of the University of Minnesota research team include Taegon Kim and Chenxi Lin from Jin’s group and David Mulla from the Department of Soil, Water, and Climate.

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The study was conducted by Professor Frank Hu and colleagues at the Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, MA, USA, and aimed to identify the metabolite profiles related to different plant-based diets and investigate possible associations between those profiles and the risk of developing T2D.

A metabolite is a substance used or produced by the chemical processes in a living organism and includes the vast number of compounds found in different foods as well as the complex variety of molecules created as those compounds are broken down and transformed for use by the body. Differences in the chemical makeup of foods means that an individual’s diet should be reflected in their metabolite profile. Recent technological advances in the field of high-throughput metabolomics profiling have ushered in a new era of nutritional research. Metabolomics is defined as the comprehensive analysis and identification of all the different metabolites present within a biological sample.

Over 90% of diabetes cases are the type 2 form, and the condition poses a major threat to health around the world. Global prevalence of the disease in adults has more than tripled in less than two decades, with cases increasing from around 150 million in 2000 to over 450 million in 2019 and projected to rise to around 700 million in 2045.

The global health burden of T2D is further increased by the numerous complications arising from the disease, both macrovascular, such as cardiovascular disease, and microvascular, which damage the kidneys, the eyes, and the nervous system. The diabetes epidemic is primarily caused by unhealthy diets, having overweight or obesity, genetic predisposition, and other lifestyle factors such as a lack of exercise. Plant-based diets, especially healthy ones rich in high quality foods such as whole grains, fruits, and vegetables, have been associated with a lower risk of developing T2D but the underlying mechanisms involved are not fully understood.

The team conducted an analysis of blood plasma samples and dietary intake of 10,684 participants from three prospective cohorts (Nurses’ Health Study, Nurses’ Health Study II and Health Professionals Follow-up Study). Participants were predominantly white, middle-aged (mean age 54 years), and with a mean body mass index (BMI) of 25.6kg/m².

Study participants completed food frequency questionnaires (FFQs) which were scored according to their adherence to three plant-based diets: an overall Plant-based Diet Index (PDI), a healthy Plant-based Diet Index (hPDI), and an Unhealthy Plant-Based Diet Index (uPDI). Diet indices were based on that individual’s intake of 18 food groups: healthy plant foods (whole grains, fruits, vegetables, nuts, legumes, vegetable oils, and tea/coffee); unhealthy plant foods (refined grains, fruit juices, potatoes, sugar-sweetened beverages, and sweets/desserts); and animal foods (animal fats, dairy, eggs, fish/seafood, meat, and miscellaneous animal-based foods). The team distinguished between healthy and unhealthy plant foods according to their association with T2D, cardiovascular disease, certain cancers, and other conditions, including obesity and high blood pressure.

The researchers tested blood samples taken back in late 1980s and 1990s in the early phase of the three studies mentioned above to create metabolite profile scores for the participants, and any cases of incident T2D during the follow-up period of the study were recorded. Analyses of these data together with the diet index scores enabled the team to find any correlations between metabolite profile, diet index, and T2D risk.

The study found that compared with participants who did not develop T2D, those who were diagnosed with the disease during follow-up had a lower intake of healthy plant-based foods, as well as lower scores for PDI and hPDI. In addition, they had a higher average BMI, and were more likely to have high blood pressure and cholesterol levels, use blood pressure and cholesterol drugs, have a family history of diabetes, and be less physically active.

The metabolomics data revealed that plant-based diets were associated with unique multi-metabolite profiles, and that these patterns differed significantly between the healthy and unhealthy plant-based diets. In addition, metabolite profile scores for both the overall plant-based diet and the healthy plant-based diet were inversely associated with incident T2D in a generally healthy population, independent of BMI, and other diabetes risk factors, while no association was observed for the unhealthy plant-based diet. As a result, higher metabolite profile scores for PDI and hPDI indicated both closer adherence to those diets and having a lower risk of developing T2D.

Further analysis revealed that after adjusting for levels of trigonelline, hippurate, isoleucine, a small set of triacyglycerols (TAGs), and several other intermediate metabolites, the association between plant-based diets and T2D largely disappeared, suggesting that they might play a key role in linking those diets to incident diabetes. Trigonelline, for example, is found in coffee and has demonstrated beneficial effects on insulin resistance in animal studies, while higher levels of hippurate are associated with better glycaemic control, enhanced insulin secretion and lower risk of T2D. The team suggest that these metabolites could be investigated further and may provide mechanistic explanations of how plant-based diets can have a beneficial effect on T2D risk.

Professor Hu explains: “While it is difficult to tease out the contributions of individual foods because they were analysed together as a pattern, individual metabolites from consumption of polyphenol-rich plant foods like fruits, vegetables, coffee, and legumes are all closely linked to healthy plant-based diet and lower risk of diabetes.”

The authors conclude: “Our findings support the beneficial role of healthy plant-based diets in diabetes prevention and provide new insights for future investigation…our findings regarding the intermediate metabolites are at the moment intriguing but further studies are needed to confirm their causal role in the associations of plant-based diets and the risk of developing type 2 diabetes.”

Since they only collected blood samples at one point in time, the authors also believe that long-term repeated metabolomics data are needed to understand how dietary changes relate to changes in metabolome, thereby influencing T2D risk.