Human radiological safety assessment for petawatt laser-driven ion acceleration experiments in CLAPA-T

The newly built Compact Laser Plasma Accelerator-Therapy facility at Peking University will deliver 60 J/1 Hz laser pulses with 30 fs duration.Driven by this petawatt laser facility,proton beams with energy up to 200 MeV are expected to be generated for tumor therapy.During high-repetition operation,both prompt radiation and residual radiation may cause safety problems.Therefore,human radiological safety assessment before commissioning is essential.In this paper,we simulate both prompt and residual radiation using the Geant4 and FLUKA Monte Carlo codes with reasonable proton and as-produced electron beam parameters.We find that the prompt radiation can be shielded well by the concrete wall of the experimental hall,but the risk from residual radiation is nonnegligible and necessitates adequate radiation cooling.On the basis of the simulation results,we discuss the constraints imposed by radiation safety considerations on the annual working time,and we propose radiation cooling strategies for different shooting modes.

Effects of surface chlorine atoms on charge distribution and reaction barriers for photocatalytic CO_(2)reduction

Photocatalytic CO_(2)reduction to produce high value-added carbon-based fuel has been proposed as a promising approach to mitigate global warming issues.However,the conversion efficiency and product selectivity are still low due to the sluggish dynamics of transfer processes involved in proton-assisted multi-electron reactions.Lowering the formation energy barriers of intermediate products is an effective method to enhance the selectivity and productivity of final products.In this study,we aim to regulate the surface electronic structure of Bi_(2)WO_(6)by doping surface chlorine atoms to achieve effective photocatalytic CO_(2)reduction.Surface Cl atoms can enhance the absorption ability of light,affect its energy band structure and promote charge separation.Combined with DFT calculations,it is revealed that surface Cl atoms can not only change the surface charge distribution which affects the competitive adsorption of H_(2)O and CO_(2),but also lower the formation energy barrier of intermediate products to generate more intermediate*COOH,thus facilitating CO production.Overall,this study demonstrates a promising surface halogenation strategy to enhance the photocatalytic CO_(2)reduction activity of a layered structure Bi-based catalyst.

Higher intakes of lysine,threonine and valine are inversely associated with non-alcoholic fatty liver disease risk:a community-based case-control study in the Chinese elderly

The associations of individual amino acid with non-alcoholic fatty liver disease(NAFLD)risk remained unclear.The present study aimed to investigate the associations between the two in the Chinese elderly.Methods:A community-based health check-up program was conducted in Qingdao,China.NAFLD was diagnosed by ultrasonography accompanied by epidemiological investigation.The dietary intakes of amino acids were investigated with 3-day,24-h dietary records and calculated by Nutrition Calculator software.Restricted cubic spline model was used to evaluate a nonlinear relationship between amino acid intake and NAFLD risk.Results:400 NAFLD subjects were identified,and 400 participants were randomly selected as controls and matched by gender and age(±3 years)Dose-response analysis showed that 1000 mg increment of aromatic amino acids(AAAs)was associated with reduced 16%risk of NAFLD.Dietary increments of 750 mg/d threonine,950 mg/d valine,or 1700 mg/d lysine were associated with a 20%reduction in the NAFLD risk(all P for linearity<0.05).Conclusion:The present study demonstrated that the dietary increases in milk,eggs and deep-sea fish,which are rich in the amino acids,might contribute to protecting against NAFLD in the elderly.

High-energy-density plasma in femtosecond-laser-irradiated nanowire-array targets for nuclear reactions

In this work,the high-energy-density plasmas(HEDP)evolved from joule-class-femtosecond-laser-irradiated nanowire-array(NWA)targets were numerically and experimentally studied.The results of particle-in-cell simulations indicate that ions accelerated in the sheath field around the surfaces of the nanowires are eventually confined in a plasma,contributing most to the high energy densities.The protons emitted from the front surfaces of the NWA targets provide rich information about the interactions that occur.We give the electron and ion energy densities for broad target parameter ranges.The ion energy densities from NWA targets were found to be an order of magnitude higher than those from planar targets,and the volume of the HEDP was several-fold greater.At optimal target parameters,8%of the laser energy can be converted to confined protons,and this results in ion energy densities at the GJ/cm^(3) level.In the experiments,the measured energy of the emitted protons reached 4 MeV,and the changes in energy with the NWA’s parameters were found to fit the simulation results well.Experimental measurements of neutrons from 2H(d,n)3He fusion with a yield of(24±18)×10^(6)/J from deuterated polyethylene NWA targets also confirmed these results.

Allelic variation in the coumarate 3-hydroxylase gene associated with wood properties of Catalpa fargesii Bur.

Coumarate 3-hydroxylase(C3h)genes participate in the synthesis of lignin and may affect the properties of wood that are important for its commercial value.A better understanding of the natural variation in C3h genes and their associations to wood properties is required to effectively improve wood quality.We used a candidate gene-based association mapping approach to identify CfC3h allelic variants associated with traits that affect the wood properties of Catalpa fargesii.We first isolated the full-length CfC3h cDNA(1825 bp),which was expressed at relatively high levels in xylem according to real time-polymerase chain reaction.In totally,17 common single-nucleotide polymorphisms(minor allele frequency>5%)were identified through cloning and sequencing the CfC3h locus from a mapping population(including 88 unrelated natural C.fargesii individuals collected from main distribution area).Nucleotide diversity and linkage disequilibrium(LD)in CfC3h indicate that CfC3h has low nucleotide diversity(π_(t)=0.0031 andθ_(w)=0.0103)and relatively low LD(within 1800 bp;r^(2)≥0.1).An association analysis identified eight common single-nucleotide polymorphisms(SNPs)(false discovery rate,Q<0.10)and ten haplotypes(Q<0.10)associated with wood properties,explaining 4.92-12.09%of the phenotypic variance in an association population consisted of 125 unrelated natural individuals(The 88 individuals from the mapping population were comprised in the association population).Our study would provide new insight into C3h gene affecting wood quality,and the SNP markers identified would have potential applications in marker-assisted breeding in the future.

乙酰基四肽-11防脱发作用的研究

将乙酰基四肽-11应用于小鼠进行脱发研究。通过对C57BL/6雌性小鼠背部进行脱毛处理,实验组连续涂抹3个质量浓度梯度(10,20和30μg/mL)的乙酰基四肽-11水溶液18天,对照组涂抹生理盐水,观察小鼠背部毛发生长情况,HE染色进行组织学分析,并初步进行了志愿者试用评估。结果表明,一定质量浓度的乙酰基四肽-11可以预防小鼠脱发,避免毛囊微型化,同时可以维持小鼠表皮紧致。志愿者试用评估表明测试样品对所有志愿者都有防脱发效果,85%志愿者反馈头发密度变大。

Genetic architecture of leaf morphology revealed by integrated trait module in Catalpa bungei

Leaves are crucial for maintaining plant growth and development via photosynthesis,and their function is simultaneously regulated by a suite of phenotypic traits.Although much is known about the genetic architecture of individual leaf traits,unraveling the genetic basis of complex leafmorphology remains a challenge.Based on the functional correlation and coordination ofmulti-traits,we divided 15 leaf morphological traits into three modules,comprising size(area,length,width,and perimeter),shape(leaf lobes,aspect ratio,circularity,rectangularity,and the relevant ratios),and color(red,green,and blue)for an ornamental tree species,Catalpa bungei.A total of 189 significant single-nucleotide polymorphisms were identified in the leaves of C.bungei:35,82,and 76 in the size,shape,and color modules,respectively.Four quantitative trait loci were common between the size and shape modules,which were closely related according to phenotype correlation,genetic mapping,and mRNA analysis.The color module was independent of them.Synergistic changes in the aspect ratio,leaf lobe,and circularity suggest that these traits could be the core indicators of the leaf shape module.The LAS and SRK genes,associated with leaf lobe and circularity,were found to function in plant defense mechanisms and the growth of leaves.The associations between the SRK and CRK2 genes and the leaf lobe and circularity traits were further verified by RT-qPCR.Our findings demonstrate the importance of integrating multi-trait modules to characterize leaf morphology and facilitate a holistic understanding of the genetic architecture of intraspecific leaf morphology diversity.

AIMP1衍生肽的护肤功效研究

皮肤糖化反应是导致肤色暗黄、色斑、老化的一个重要因素,针对皮肤糖化问题,开发了一种生物活性多肽并进行护肤功效验证。AIMP1衍生肽(AdP)是由氨基酰tRNA合成酶相互作用多功能蛋白质1(AIMP1)衍生而来的寡肽,具有类AIMP1的多种生物活性。采用牛血清白蛋白(BSA)糖化和羰基化体系研究AdP的抗糖化效果,并对含AdP的样品进行了临床功效测试。结果表明:AdP可减缓BSA与葡萄糖的糖基化反应,减少蛋白质羰基的生成,具有浓度依赖性;皮肤角质层含水量显著提高27.32%,TEWL降低12.77%,R2值提高10.34%,ITA°值提高14.25%,皱纹面积减少12.14%,AdP可有效抑制蛋白糖化,具有提升屏障功能、祛黄提亮抗皱的功效。

Peroxidase-like active Cu-ZIF-8 with rich copper(I)-nitrogen sites for excellent antibacterial performances toward drug-resistant bacteria

Bacterial pathogens pose a serious threat to human health,and there is an urgent need to develop highly effective antibacterial materials to eliminate the increasingly serious contamination of drug-resistant bacteria.Here,a Cu-doped ZIF-8 particle with unsaturated copper exhibits high peroxidase-like activity.99.998%antibacterial efficiency against S.aureus can be achieved for 30 min at a low concentration of 50μg·mL^(−1),as well as complete sterilization against E.coli(up to 8 log).99.999%antibacterial efficiency against Methicillin-resistant Staphylococcus aureus can be achieved,performing orders of magnitude higher than Vancomycin.The mechanism shows that the unsaturated Cu-Nx sites are enzyme-like active centers,which could promote the consumption of bacteria reducing substances by H_(2)O_(2),and the generated*OH further aggravates bacterial oxidative stress and membrane damage.More importantly,the oxidation activity of adsorbed oxygen species on Cu-ZIF-8 is enhanced by charge transfer and structural changes between the ligand and copper center like natural enzymes.Cu-doped ZIF-8 with peroxidase-like activity shows great potential in antibacterial application and the revealed catalytic mechanism is helpful for understanding the high antibacterial activity of nanoparticles with Cu-Nx sites.

Early evaluation of growth traits of Larix kaempferi clones

Early selection is an important method to shorten the breeding cycle for tree species, which may differ in the time for early selection. To evaluate the early selected time for Larix kaempferi, tree height and diameter at breast height of 57 L. kaempferi clones were measured over many different growth years. The results indicated that, except for age × clone interaction for diameter at breast height （P = 0.741）, there were significant differences among all variation sources （P 〈 0.01）. The coefficient of phenotypic variation ranged from 14.89 to 35.65% for height and from 19.17 to 23.86% for diameter at breast height in different growth years. The repeatability of height and of diameter at breast height among clones was high, ranging from 0.6181 to 0.8531 （height） and from 0.8443 to 0.8497 （diameter at breast height）, in different growth years. There were significant positive correlations between all pairs of growth traits except between height in the 2nd growth year and height in the 30th growth year; and between height in the 2nd growth year × diameter at breast height in the 30th growth year. With a comprehen- sive evaluation method and a selection ratio of 10%, L65, L1, L62, L9, L15, and L78 were selected as excellent clones in the 30th growth year. Their average values of height and diameter at breast height were 9.81 and 16.57% higher than the overall average, representing genetic gains of 6.46 and 13.99%, respectively. This study provides a theoretical foundation for the genetic improvement of L. kaempferi.

Overexpression of CfPIP1-1,CfPIP1-2,and CfPIP1-4 genes of Catalpa fargesii in transgenic Arabidopsis thaliana under drought stress

Catalpa fargesii is an important economic tree species used for furniture and timber production because of its high density and hardness.Its survival and growth are severely aff ected and primarily limited by drought stress.Thus,to better understand the mechanism of drought resistance in C.fargesii,we used qRT-PCR to reveal signifi cantly diff erent expression of three plasma membrane intrinsic protein genes:CfPIP1-1,CfPIP1-2 and CfPIP1-4.We then cloned their full-length cDNA sequences and characterized the encoded proteins.We analyzed the genes phylogenetically and predicted conserved motifs,domains,and secondary and tertiary structures.To verify the function ofthe CfPIP1 genes further,we ectopically expressed CfPIP1 transgenes in Arabidopsis thaliana.The results showed that CfPIP1-1,CfPIP1-2 and CfPIP1-4 had several characteristics of aquaporins.The transgenic plants grew better than the WT plants did under drought stress,and overexpression of the CfPIP1 genes increased the plant water content and resistance to drought.Thus,CfPIP1-1,CfPIP1-2 and CfPIP1-4 of C.fargesii play key roles in regulating the intracellular and extracellular water balance and in mediating the plant response to drought.

Evaluatingα-galactosylceramide as an adjuvant for live attenuated infuenza vaccines in pigs

Natural killer T(NKT)cells activated with the glycolipid ligandα-galactosylceramide(α-GalCer)stimulate a wide variety of immune cells that enhance vaccine-mediated immune responses.Several studies have used this approach to adjuvant inactivated and subunit infuenza A virus(IAV)vaccines,including to enhance cross-protective infuenza immunity.However,less is known about whetherα-GalCer can enhance live attenuated infuenza virus(LAIV)vaccines,which usually induce superior heterologous and heterosubtypic immunity compared to non-replicating infuenza vaccines.The current study used the swine infuenza challenge model to assess whetherα-GalCer can enhance cross-protective immune responses elicited by a recombinant H3N2 LAIV vaccine(TX98ΔNS1)encoding a truncated NS1 protein.In one study,weaning pigs were administered the H3N2 TX98ΔNS1 LAIV vaccine with 0,10,50,and 100μg/kg doses ofα-GalCer,and subsequently challenged with a heterologous H3N2 virus.All treatment groups were protected from infection.However,the addition ofα-GalCer appeared to suppress nasal shedding of the LAIV vaccine.In another experiment,pigs vaccinated with the H3N2 LAIV,with or without 50μg/kg ofα-GalCer,were challenged with the heterosubtypic pandemic H1N1 virus.Pigs vaccinated with the LAIV alone generated cross-reactive humoral and cellular responses which blocked virus replication in the airways,and signifcantly decreased virus shedding.On the other hand,combining the vaccine withα-GalCer reduced cross-protective cellular and antibody responses,and resulted in higher virus titers in respiratory tissues.These fndings suggest that:(i)high doses ofα-GalCer impair the replication and nasal shedding of the LAIV vaccine;and(ii)α-GalCer might interfere with heterosubtypic cross-protective immune responses.This research raise concerns that should be considered before trying to use NKT cell agonists as a possible adjuvant approach for LAIV vaccines.

Global Lysine Acetylome Analysis of Flower Bud Development in Catalpa bungei

Lysine acetylation,a reversible and dynamic post-translational modification,plays pivotal roles in regulating many biological processes in plants.However,the information of lysine acetylation during flower development of woody angiosperm remains unclear.Herein,we identified a total of 667 lysine acetylation sites in 467 proteins in flower buds of Catalpa Bungei.The acetylated proteins were mainly involved in the pathways of carbon metabolism,glycometabolism and oxidative phosphorylation.Using functional enrichment analysis,61 and 13 acetylated proteins were involved in the glycometabolism and oxidative phosphorylation pathways,respectively.This suggests that lysine acetylated proteins play critical roles in the energy metabolism pathways.Accordingly,the protein–protein interactions were also highly enriched in the carbon metabolic pathway.Integrative analysis of lysine acetylome and transcriptome showed that transcript level changes of seven key lysine-acetylated proteins/genes involved in energy metabolism were significant different during floral transition.Importantly,compared with the normal flowering variety,the expression levels of phosphoribulokinase,phosphoenolpyruvate carboxykinase,ATP synthase and pyruvate dehydrogenase complex genes were significantly up-regulated at the stages of vegetative and transition buds during early flowering of C.bungei.These data represent the first lysine acetylome in the C.bungei flowers,and can serve as an essential basis for exploring the function of lysine acetylated proteins in the flower bud development of plants.

Commissioning experiment of the high-contrast SILEX-Ⅱ multi-petawatt laser facility

The results of a commissioning experiment on the SILEX-Ⅱlaser facility(formerly known as CAEP-PW)are reported.SILEX-Ⅱis a complete optical parametric chirped-pulse amplification laser facility.The peak power reached about 1 PWin a 30 fs pulse duration during the experiment.The laser contrast was better than 1010 at 20 ps ahead of the main pulse.In the basic laser foil target interaction,a set of experimental data were collected,including spatially resolved x-ray emission,the image of the coherent transition radiation,the harmonic spectra in the direction of reflection,the energy spectra and beam profile of accelerated protons,hot-electron spectra,and transmitted laser energy fraction and spatial distribution.The experimental results show that the laser intensity reached 531020 W/cm^(2) within a 5.8μm focus(FWHM).Significant laser transmission did not occur when the thickness of theCHfoil was equal to or greater than 50 nm.The maximum energy of the accelerated protons in the target normal direction was roughly unchanged when the target thickness varied between 50 nm and 15μm.The maximum proton energy via the target normal sheath field acceleration mechanism was about 21 MeV.We expect the on-target laser intensity to reach 10^(22) W/cm^(2) in the near future,after optimization of the laser focus and upgrade of the laser power to 3 PW.

A comprehensive diagnostic system of ultra-thin liquid sheet targets

To meet the demands of laser-ion acceleration at a high repetition rate,we have developed a comprehensive diagnostic system for real-time and in situ monitoring of liquid sheet targets(LSTs).The spatially resolved rapid characterizations of an LST’s thickness,flatness,tilt angle and position are fulfilled by different subsystems with high accuracy.With the help of the diagnostic system,we reveal the dependence of thickness distribution on collision parameters and report the 238-nm liquid sheet generated by the collision of two liquid jets.Control methods for the flatness and tilt angle of LSTs have also been provided,which are essential for applications of laser-driven ion acceleration and others.

A Protocol for Developing Chinese Clinical Practice Guidelines of Hypertension

To improve the standard screening, diagnosis, and treatment of hypertension in patients in China;realize the standardization of clinical practice of hypertension;and improve the prevention and control level of hypertension in China, it is both important and necessary to develop a clinical practice guideline for hypertension according to a recognized methodology. Jointly sponsored by the National Center for Cardiovascular Diseases, Chinese Medical Doctor Association, Hypertension Committee of the Chinese Medical Doctor Association, Chinese Society of Cardiology, and Hypertension Committee of Cross-Straits Medicine Exchange Association, the “Chinese Clinical Practice Guidelines of Hypertension” was proposed. Research Unit of Evidence-Based Evaluation and Guidelines, Chinese Academy of Medical Sciences, Guideline and Standards Research Centre of Chinese Medical Association Publishing House, Lanzhou University Institute of Health Data Science, and Lanzhou University GRADE Center will provide methodological support for the guidelines.

Fabrication of large-area uniform carbon nanotube foams as near-critical-density targets for laser–plasma experiments

Carbon nanotube foams(CNFs)have been successfully used as near-critical-density targets in the laser-driven acceleration of high-energy ions and electrons.Here we report the recent advances in the fabrication technique of such targets.With the further developed floating catalyst chemical vapor deposition(FCCVD)method,large-area(>25 cm^(2))and highly uniform CNFs are successfully deposited on nanometer-thin metal or plastic foils as double-layer targets.The density and thickness of the CNF can be controlled in the range of 1−13 mg/cm^(3)and 10−200µm,respectively,by varying the synthesis parameters.The dependence of the target properties on the synthesis parameters and the details of the target characterization methods are presented for the first time.

Association Between COVID-19 Vaccination Coverage and Case Fatality Ratio:a Comparative Study—Hong Kong SAR,China and Singapore,December 2021–March 2022

Summary What is already known about this topic?Hong Kong Special Administrative Region(SAR),China and Singapore are both facing considerable Omicron variant epidemic.However,the overwhelmed medical system and high case fatality ratio(CFR)just occurred in Hong Kong SAR,China but not in Singapore.What is added by this report?The low vaccination coverage in Hong Kong SAR,China,especially among the older adults,is shown to be a primary reason of its recent high CFR.What are the implications for public health practice?Facing the potential epidemic risk,non-vaccinated,non-fully-vaccinated,and non-booster-vaccinated people in China,especially the elderly,should get any type of accessible vaccine,which could save lives when the infection unfortunately befalls.

Laser-induced damage thresholds of ultrathin targets and their constraint on laser contrast in laser-driven ion acceleration experiments

Single-shot laser-induced damage threshold(LIDT)measurements of multi-type free-standing ultrathin foils were performed in a vacuum environment for 800 nm laser pulses with durationsτranging from 50 fs to 200 ps.The results show that the laser damage threshold fluences(DTFs)of the ultrathin foils are significantly lower than those of corresponding bulk materials.Wide band gap dielectric targets such as SiN and formvar have larger DTFs than semiconductive and conductive targets by 1–3 orders of magnitude depending on the pulse duration.The damage mechanisms for different types of targets are studied.Based on the measurement,the constrain of the LIDTs on the laser contrast is discussed.

An automated, 0.5 Hz nano-foil target positioning system for intense laser plasma experiments

We report on a target system supporting automated positioning of nano-targets with a precision resolution of 4 μm in three dimensions. It relies on a confocal distance sensor and a microscope. The system has been commissioned to position nanometer targets with 1 Hz repetition rate. Integrating our prototype into the table-top ATLAS 300 TW-laser system at the Laboratory for Extreme Photonics in Garching, we demonstrate the operation of a 0.5 Hz laser-driven proton source with a shot-to-shot variation of the maximum energy about 27% for a level of confidence of 0.95. The reason of laser shooting experiments operated at 0.5 Hz rather than 1 Hz is because the synchronization between the nano-foil target positioning system and the laser trigger needs to improve.