National University of Singapore(NUS)nutritionists have found that 5-Hydroxytryptophan(5-HTP)supplementation can improve sleep quality in Singaporean older adults,particularly in individuals with poor sleep patterns,and manage their gut microbiome composition.Ensuring good sleep quality is an integral part of achieving good health.However,a mental health study published in 2022 reported that close to 17 per cent of older adults aged 65 and above in Singapore are suffering from poor sleep quality,which has been linked to worse health outcomes,such as agreater risk of chronic diseases and cognitive impairment.There is growing evidence on the association between gut microbiota composition and sleep quality.Additionally,there are pharmaceutical sleep aids available to help poor sleepers achieve agood night’s sleep.However,such aids may induce adverse side effects,including digestive problems and headaches.Dietary supplements,such as anaturally occurring amino acid,5-HTP,are available,but its efficacy on sleep quality in older adults is unclear.Through a12-week clinical trial on 30 older adults,aged 65 and over,NUS researchers set out to evaluate the impact of 5-HTP supplementation on sleep quality and gut microbiota composition on older adults.The research team was led by Assistant Professor Kim Jung Eun from the Department of Food Science and Technology(NUS FST)under the NUS Faculty of Science,and the study was conducted in collaboration with Adjunct Associate Professor Johnson Fam from the Department of Psychological Medicine at the NUS Yong Loo Lin School of Medicine.Based on the results of the clinical trial,the NUS team discovered that supplementation of 5-HTP can improve sleep quality in Singaporean older adults and this improvement was predominantly observed in poor sleepers which could be linked to the modulation of their gut microbiome composition.The team’s findings were published in the journal Clinical Nutrition on 17 January 2024. 查看详细>>

本工作利用表面原生氧化层缺陷锚定策略将Ni单原子锚定在泡沫钛表面，制备了具有孤立非对称性Ni–O–Ti位点的Ni单原子整体钛电极，彻底规避了桥连对称性Ni–O–Ni位点的形成。其中，强亲氧Ti位点与尿素C=O基团作用，以氧端构型吸附尿素，增加了尿素分子C?N键的共振电子云密度，从而避免C?N键过早断裂，促进分子内N–N偶联选择性生成N2。在1.40 VRHE电位下，实现了99%的N2选择性和22.0 mL h–1阴极产氢速率。进一步以商业太阳能单晶硅为电源，构建了可再生能源驱动的高效电解尿液制氢原型装置。本研究实现了尿素的选择性氧化，并阐明了尿素选择性氧化机制，为电解富尿素污水制氢技术奠定了理论基础。球差校正透射电镜和同步辐射证明，Ni以单原子形式分散在泡沫钛表面，通过O桥键与次外层的Ti原子配位，形成孤立的非对称性Ni–O–Ti位点，规避了对称桥连的Ni–O–Ni位点。非对称性Ni–O–Ti位点在1.30 VRHE电位下即可实现10 mA cm–2尿素氧化电流密度。更重要的是，该电极尿素氧化的N2选择性高达99%，几乎不产生氰酸盐和（亚）硝酸盐有害产物，在长达10天的运行过程中始终保持出色的尿素氧化活性和N2选择性。含15N同位素的尿素氧化实验表明，生成的N2来自单个尿素分子内的N–N偶联。原位电化学拉曼光谱和傅里叶变换红外光谱证明，与传统的氮端尿素吸附构型不同，非对称Ni–O–Ti中的强亲氧Ti位点以氧端构型吸附尿素、向尿素分子的C?N键注入电子，导致C?N键红外振动蓝移，从而强化、稳定了C?N键，提高了尿素氧化至N2的选择性。DFT模拟验证了尿素分子以氧端构型吸附在Ni–O–Ti位点，并进一步定量化了不同构型尿素分子C?N键的共振电子云密度和键强；尿素氧化吉布斯自由能计算发现，氧端吸附构型的尿素倾向于发生分子内N–N偶联形成N2，而氮端吸附构型的尿素倾向于发生C?N键断裂，最终形成氰酸盐和（亚）硝酸盐，阐明了吸附构型依赖的尿素选择性氧化机制。基于非对称Ni–O–Ti位点尿素选择性氧化，该团队构建了太阳能驱动的电解尿液耦合阴极制氢原型装置。该装置将制氢的太阳能理论能量利用率提升到9.6%，具有良好的尿液脱氮效率和稳定的制氢活性，为实际尿液处理和资源化提供了一种有前景的方案。 查看详细>>

06 August 2024 Silica dust Credit:Patrick Howlett view large Scientists have found that aworker’s lifetime exposure to‘permissible’levels of silica dust results in aconsiderable risk of developing silicosis.New research led by Imperial College London has found that workplace exposure to silica dust is linked to an increased risk of the acute lung condition silicosis and recommends current occupational exposure limits should be halved.Silicosis is aprogressive incurable lung disease caused by breathing in silica dust.Millions of people around the world work in jobs where they are exposed to silica dust,including miners,pottery workers and those involved in the manufacture and fitting of quartz and granite kitchen counters.The UK’s legal occupational limit is 0.1mg/m3 but there is alower limit in some other countries.An All Party Parliamentary group in the UK Government has called for evidence regarding whether current occupational exposure levels are safe.The researchers,at Imperial’s National Heart and Lung Institute,looked at all the available evidence relating to silicosis research,including studies drawing on x-rays,post-mortem examination results,and death certificates.They wanted to establish the cumulative risk of silicosis and identify the exposure level at which the risk would be reduced.In the research,published in the journal‘Thorax’journal today,the team assessed eight studies,involving 8792 cases of silicosis among 65,977 participants. 查看详细>>

Scientists from the Sainsbury Laboratory at Cambridge University and Jagiellonian University,Poland made the discovery while undertaking an evolutionary survey of the microscopic structure of wood from some of the world’s most iconic trees and shrubs.?They found that Tulip Trees,which are related to magnolias and can grow over 30 metres(100 feet)tall,have aunique type of wood.This discovery may explain why the trees,which diverged from magnolias when earth‘s atmospheric CO2 concentrations were relatively low,grow so tall and so fast.This opens new opportunities to improve carbon capture and storage in plantation forests by planting afast-growing tree more commonly seen in ornamental gardens,or breeding Tulip Tree-like wood into other tree species.The discovery was part of an evolutionary survey of the microscopic structure of wood from 33 tree species from the Cambridge University Botanic Garden’s Living Collections.The survey explored how wood ultrastructure evolved across softwoods(gymnosperms such as pines and conifers)and hardwoods(angiosperms including oak,ash,birch,and eucalypts).?The wood samples were collected from trees in the Botanic Garden in coordination with its Collections Coordinator.Fresh samples of wood,deposited in the previous spring growing season,were collected from aselection of trees to reflect the evolutionary history of gymnosperm and angiosperm populations as they diverged and evolved.?Using the Sainsbury Laboratory‘s low temperature scanning electron microscope(cryo-SEM),the team imaged and measured the size of the nanoscale architecture of secondary cell walls(wood)in their native hydrated state.Microscopy Core Facility Manager at the Sainsbury Laboratory,Dr Raymond Wightman,said:“We analysed some of the world’s most iconic trees like the Coast Redwood,Wollemi Pine and so-called‘living fossils‘such as?Amborella trichopoda,which is the sole surviving species of afamily of plants that was the earliest still existing group to evolve separately from all other flowering plants.“Our survey data has given us new insights into the evolutionary relationships between wood nanostructure and the cell wall composition,which differs across the lineages of angiosperm and gymnosperm plants.Angiosperm cell walls possess characteristic narrower elementary units,called macrofibrils,compared to gymnosperms.”?The researchers found the two surviving species of the ancient Liriodendron genus,commonly known as the Tulip Tree(Liriodendron tulipifera)and Chinese Tulip Tree(Liriodendron chinense)have much larger macrofibrils than their hardwood relatives.Hardwood angiosperm macrofibrils are about 15 nanometres in diameter and faster growing softwood gymnosperm macrofibrils have larger 25 nanometre macrofibrils.Tulip Trees have macrofibrils somewhere in between,measuring 20 nanometres. 查看详细>>

DALLAS–July 31,2024–Researchers at UT Southwestern Medical Center have discovered that adiet free of the amino acid tryptophan can effectively halt the growth of liver cancer in mice.Their findings,published in Nature Communications,offer new insights for dietary-based cancer treatments and highlight the critical role of the tryptophan metabolite indole 3-pyruvate(I3P)in liver tumor development.“This work demonstrates that tailored dietary modulation may serve as apowerful adjuvant in cancer treatment,”said study leader Maralice Conacci-Sorrell,Ph.D.,Associate Professor of Cell Biology and Children’s Medical Center Research Institute at UT Southwestern(CRI)and amember of the Cellular Networks in Cancer Research Program of the Harold C.Simmons Comprehensive Cancer Center.“It builds on our lab’s discovery that the universal oncogene MYC increases the demand for tryptophan in liver tumors.”Hepatocellular carcinoma(HCC)is the third-leading cause of cancer-related mortality worldwide,according to 2020 data from the World Health Organization,with limited options for effective treatment and afive-year survival rate of about 30%.The study shows that growth of liver cancers driven by the MYC oncogene is particularly dependent on tryptophan,which is converted into I3P as well as other metabolites.By removing tryptophan from the diet of mice,researchers stopped the growth of MYC-driven liver tumors and restored normal gene expression in liver cells.Notably,this dietary intervention did not affect protein synthesis in normal cells,suggesting atargeted therapeutic approach that spares healthy tissues.“Liver tumors require large amounts of tryptophan to generate the oncometabolite I3P,”Dr.Conacci-Sorrell said.“A tryptophan-free diet prevents liver tumor growth by amechanism that depends on I3P but is independent of translation,the process by which proteins are synthesized from amino acid building blocks.Because tryptophan is the amino acid with the lowest abundance in the proteome,short-term dietary manipulation is safe for healthy tissues but not for cancer cells.” 查看详细>>

A‘human challenge’study–purposefully infecting volunteers with malaria–has revealed crucial insights into how new,more effective malaria vaccines can be designed.Malaria is transmitted by certain species of mosquitoes and was responsible for an estimated 608,000 deaths in 2022,largely in sub-Saharan Africa.The trial showed that the principle behind most vaccines–producing antibodies that attach to the pathogen and block it from entering human cells–is only part of the story for malaria infection.Instead,antibodies that effectively‘recruit’other parts of the immune system were shown to be more protective against the illness in malaria infection.The international research team have already isolated one potential route to producing these kinds of antibodies,and are manufacturing experimental vaccines on multiple platforms to identify which one induces the best response.The research,led by scientists from Imperial College London,Heidelberg University Hospital and the Kenya Medical Research Institute,is published in the journals Immunity and Life Science Alliance.Lead researcher Professor Faith Osier,Co-Director of the Institute of Infection and Chair in Malaria Immunology&Vaccinology in the Department of Life Sciences at Imperial College London,and Director of Chanjo Hub,said:“Malaria is still aserious burden that kills hundreds of thousands of people every year,mostly children under five years old.We have many tools to fight the disease,but progress has stalled,and we badly need malaria vaccines that are highly effective and offer long-term protection.“Our study shows that the way we have been thinking about vaccines is too narrow in terms of how they might work.These findings could improve vaccines for malaria and beyond,potentially saving many lives worldwide.” 查看详细>>

“Our findings support shared biological pathways underlying both heart failure and frailty,suggesting interventions to prevent or treat one outcome may help decrease the burden of the other,”said study leader Amil Shah,M.D.,M.P.H.,Professor of Internal Medicine in the Division of Cardiology and in the Peter O’Donnell Jr.School of Public Health at UT Southwestern.As the world’s population ages,so do the prevalence and incidence of heart failure and frailty,disorders that tend to occur in the seventh decade of life and beyond.Heart failure is characterized by an inability of the heart to keep up with the body’s demands;symptoms of frailty are ageneral loss of physical function,with features often including unintentional weight loss,physical exhaustion,and low physical activity.Frailty occurs in up to half of people with heart failure,and the risk of heart failure increases in people with frailty.Although inflammation has been implicated in both of these multisystem disorders,whether heart failure and frailty share molecular pathways has been unknown.To answer this question,Dr.Shah and colleagues across the country used data from the Atherosclerosis Risk in Communities(ARIC)study,an ongoing longitudinal study initiated in the late 1980s at sites in North Carolina,Mississippi,Minnesota,and Maryland.Originally meant to investigate factors that influence atherosclerosis risk in study participants over aseries of visits,ARIC has expanded its scope over the past four decades,including an assessment of frailty at study visits five,six,and seven between 2011 and 2019. 查看详细>>

Unlike traditional printed circuit boards,which are flat,3D circuitry enables components to be stacked and integrated vertically—dramatically reducing the footprint required for devices.Advancing the frontiers of 3D printed circuits,a team of researchers from the National University of Singapore(NUS)has developed astate-of-the-art technique-known as tension-driven CHARM3D-to fabricate three-dimensional(3D),self-healing electronic circuits.This new technique enables the 3D printing of free-standing metallic structures without requiring support materials and external pressure.The research team led by Associate Professor Benjamin Tee from the Department of Materials Science and Engineering in the NUS College of Design and Engineering used Field’s metal to demonstrate how CHARM3D can fabricate awide range of electronics,allowing for more compact designs in devices such as wearable sensors,wireless communication systems and electromagnetic metamaterials.In healthcare,for instance,CHARM3D facilitates the development of contactless vital sign monitoring devices—enhancing patient comfort while enabling continuous monitoring.In signal sensing,it optimises the performance of 3D antennas,leading to improved communication systems,more accurate medical imaging and robust security applications.The team’s findings were published in the journal Nature Electronics on 25 July 2024.Assoc Prof Tee is the corresponding author of the research paper. 查看详细>>

Researchers at the University of Toronto’s Faculty of Applied Science&Engineering have designed anovel way to recycle steel that could help decarbonize several manufacturing industries and usher in acircular steel economy.The new method introduces an innovative oxysulfide electrolyte for electrorefining,an alternative way of removing copper and carbon impurities from molten steel.The process also generates liquid iron and sulfur as by-products.It’s outlined in anew paper published in Resources,Conservation and Recycling and co-authored by Jaesuk(Jay)Paeng,a PhD candidate in the department of chemical engineering and applied chemistry,William Judge,a PhD alum from the department of materials science and engineering,and Professor Gisele Azimi from the department of chemical engineering and applied chemistry.“Our study is the first reported instance of electrochemically removing copper from steel and reducing impurities to below alloy level,”says Azimi,who holds the Canada Research Chair in Urban Mining Innovations.Currently,only 25 per cent of steel produced comes from recycled material.But the global demand for greener steel is projected to grow over the next two decades as governments around the world endeavour to achieve net-zero emission goals.Steel is created by reacting iron ore with coke–a prepared form of coal–as the source of carbon and blowing oxygen through the metal produced.Current processes generate nearly two tonnes of carbon dioxide per tonne of steel produced,making steel production one of the highest contributors to carbon emissions in the manufacturing sector.Traditional steel recycling methods use an electric arc furnace to melt down scrap metal.Since it is difficult to physically separate copper material from scrap before melting,the element is also present in the recycled steel products.“The main problem with secondary steel production is that the scrap being recycled may be contaminated with other elements,including copper,”says Azimi.“The concentration of copper adds up as you add more scrap metals to be recycled,and when it goes above 0.1 weight percentage in the final steel product,it will be detrimental to the properties of steel.”Copper cannot be removed from molten steel scrap using the traditional electric arc furnace steelmaking practice,so this limits the secondary steel market to producing lower-quality steel product,such as reinforcing bars used in the construction industry.“Our method can expand the secondary steel market into different industries,”says Paeng.“It has the potential to be used to create higher-grade products such as galvanized cold rolled coil used in the automotive sector,or steel sheets for deep drawing used in the transport sector.”To remove copper from iron to below 0.1 weight percentage,the team had to first design an electrochemical cell that could withstand temperatures up to 1,600 degrees Celsius.Inside the cell,electricity flows between the negative electrode(cathode)and positive electrode(anode)through anovel oxysulfide electrolyte designed from slag—a waste derived from steelmaking that often ends up in cement or landfills. 查看详细>>

CRI Associate Professor Prashant Mishra,M.D.,Ph.D.,Xun Wang,Ph.D.,and colleagues have found that hepatocytes,the cells responsible for most liver function,normally use their mitochondria to process fatty acids,a key energy source during regeneration.When their mitochondria are damaged,hepatocytes turn on PDK4–a metabolic enzyme that restricts cells from shifting to an alternative energy source–and cells die.“There are good and bad sides of metabolic flexibility.Although metabolic flexibility has been largely described as beneficial because it gives cells the ability to tolerate shifting environments or alternative nutritional sources,our findings suggest flexibility can also be detrimental by allowing damaged cells to survive,”Dr.Mishra said.“With mitochondrial damage,liver cells actively suppress flexibility–a good thing if it prevents the damage from spreading.”CRI scientists initially studied the mitochondria of healthy liver cells,both under normal and regenerative conditions.Their analyses showed fatty acids from other parts of the body were transported through the blood to the liver to fuel regeneration.When researchers blocked fatty acid transit,heathy livers were flexible and shifted to other energy sources,including sugars like glucose.Researchers then examined livers from mice with mutations in their mitochondrial genes.Damaged liver cells were unable to use fatty acids during regeneration and did not shift to other energy sources,preventing livers from regenerating.To understand why the flexibility was suppressed by mitochondrial mutations,Mishra Lab members examined genes that control acell’s ability to use alternate energy sources.Results showed increased levels of the PDK4 gene–a negative regulator of apathway needed to generate energy from glucose.When researchers blocked PDK4,damaged cells in the liver became metabolically flexible and were able to use other energy sources to spread and duplicate. 查看详细>>