中国大型通用光学望远镜EAST项目

为迅速缩小中国与外国在光学天文望远镜上的发展差距,北京大学拟与相关单位合作,计划在2024—2030年间逐步建成一台大口径拼接镜面通用型光学望远镜EAST,台址设在青海省海西蒙古族藏族自治州冷湖天文观测基地。项目计划按照成长型分两期建设(主镜口径分别为6 m和8 m),以大幅提高中国光学天文的观测能力,为即将发射的中国空间站工程巡天望远镜CSST和已建成的中国天眼FAST、爱因斯坦探针EP等其他波段望远镜的后续光学观测提供设备支撑,为产出世界一流科学成果提供保障,并为中国未来建设更大口径的地面光学望远镜以及发射大型空间拼接望远镜积累宝贵经验。作为通用光学望远镜,EAST将满足我国天文学家对多样化光学天文观测的迫切需求,在未来几十年从行星到恒星、从星系到宇宙的多领域科学研究中发挥重要作用。

约束Green函数与非线性地基梁模态分析

在生物和医学领域,微机电系统(MEMS)中的微梁结构在植入人体的使用时,由于体内的细胞环境类似于水凝胶,在这种环境下工作,设备和仪器的精度和稳定性很大程度上受到细胞弹性的影响.为了分析此类地基梁的动力学问题,本文建立了非线性基础上的梁振动模型,研究了任意位置弹簧和非线性弹簧基础上的梁模态.通过Laplace变换和线性叠加原理,得到了一种约束Green函数,利用数值计算验证方案的有效性,并研究了各种重要物理参数的影响,发现弹簧位置向跨中移动时,模态对称性被打破,弹簧刚度增加,模态阶数改变.

Autophagy in neuroinflammation after traumatic brain injury

Traumatic brain injury(TBI)is an acquired injury of the brain caused by the impact of external forces on the brain(Maas et al.,2008).It is a major cause of death and disability among people of all ages(Maas et al.,2008).The primary mechanical injury to the brain initiates a cascade of secondary biochemical events that lead to acute and chronic neurodegeneration and activation of inflammatory pathways(Maas et al.,2008).Both brain-resident microglia and blood-derived myeloid cells-macrophages and monocytes that infiltrate the brain due to injury-induced blood-brain barrier damage,contribute to the inflammatory responses after TBI(Morganti et al.,2015).

Mechanism of Cu entry into the brain:many unanswered questions

Brain tissue requires high amounts of copper(Cu)for its key physiological processes,such as energy production,neurotransmitter synthesis,maturation of neuropeptides,myelination,synaptic plasticity,and radical scavenging.The requirements for Cu in the brain vary depending on specific brain regions,cell types,organism age,and nutritional status.Cu imbalances cause or contribute to several life-threatening neurologic disorders including Menkes disease,Wilson disease,Alzheimer’s disease,Parkinson’s disease,and others.Despite the well-established role of Cu homeostasis in brain development and function,the mechanisms that govern Cu delivery to the brain are not well defined.This review summarizes available information on Cu transfer through the brain barriers and discusses issues that require further research.

Hybrid-Vlasov simulation of soft X-ray emissions at the Earth’s dayside magnetospheric boundaries

Solar wind charge exchange produces emissions in the soft X-ray energy range which can enable the study of near-Earth space regions such as the magnetopause,the magnetosheath and the polar cusps by remote sensing techniques.The Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)and Lunar Environment heliospheric X-ray Imager(LEXI)missions aim to obtain soft Xray images of near-Earth space thanks to their Soft X-ray Imager(SXI)instruments.While earlier modeling works have already simulated soft X-ray images as might be obtained by SMILE SXI during its mission,the numerical models used so far are all based on the magnetohydrodynamics description of the space plasma.To investigate the possible signatures of ion-kinetic-scale processes in soft Xray images,we use for the first time a global hybrid-Vlasov simulation of the geospace from the Vlasiator model.The simulation is driven by fast and tenuous solar wind conditions and purely southward interplanetary magnetic field.We first produce global X-ray images of the dayside near-Earth space by placing a virtual imaging satellite at two different locations,providing meridional and equatorial views.We then analyze regional features present in the images and show that they correspond to signatures in soft X-ray emissions of mirrormode wave structures in the magnetosheath and flux transfer events(FTEs)at the magnetopause.Our results suggest that,although the time scales associated with the motion of those transient phenomena will likely be significantly smaller than the integration time of the SMILE and LEXI imagers,mirror-mode structures and FTEs can cumulatively produce detectable signatures in the soft X-ray images.For instance,a local increase by 30%in the proton density at the dayside magnetopause resulting from the transit of multiple FTEs leads to a 12%enhancement in the line-of-sight-and time-integrated soft X-ray emissivity originating from this region.Likewise,a proton density increase by 14%in the magnetosheath associated with mirror-mode structures can result in an enhancement in the soft X-ray signal by 4%.These are likely conservative estimates,given that the solar wind conditions used in the Vlasiator run can be expected to generate weaker soft X-ray emissions than the more common denser solar wind.These results will contribute to the preparatory work for the SMILE and LEXI missions by providing the community with quantitative estimates of the effects of small-scale,transient phenomena occurring on the dayside.

A novel approach to Parkinson's disease treatment with a potentially dual-acting therapeutic agent that targetsα-synuclein aggregation and neuron death

Parkinson's disease(PD),a prevalent neurodegenerative disorder,is chara cterized by the loss of dopaminergic neurons and the aggregation ofα-synuclein protein into Lewy bodies.While the current standards of therapy have been successful in providing some symptom relief,they fail to address the underlying pathophysiology of PD and as a result,they have no effect on disease progression.

Burden of gallstone disease in the United States population:Prepandemic rates and trends

BACKGROUND Gallstone disease is one of the most common digestive disorders in the United States and leads to significant morbidity,mortality,and health care utilization.AIM To expand on earlier findings and investigate prepandemic rates and trends in the gallstone disease burden in the United States using national survey and claims databases.METHODS The National Ambulatory Medical Care Survey,National Inpatient Sample,Nationwide Emergency Department Sample,Nationwide Ambulatory Surgery Sample,Vital Statistics of the United States,Optum Clinformatics®Data Mart,and Centers for Medicare and Medicaid Services Medicare 5%Sample and Medicaid files were used to estimate claims-based prevalence,medical care including cholecystectomy,and mortality with a primary or other gallstone diagnosis.Rates were age-adjusted(for national databases)and shown per 100000 population.RESULTS Gallstone disease prevalence(claims-based,2019)was 0.70%among commercial insurance enrollees,1.03%among Medicaid beneficiaries,and 2.09%among Medicare beneficiaries and rose over the previous decade.Recently,in the United States population,gallstone disease contributed to approximately 2.2 million ambulatory care visits,1.2 million emergency department visits,625000 hospital discharges,and 2000 deaths annually.Women had higher medical care rates with a gallstone disease diagnosis,but mortality rates were higher among men.Hispanics had higher ambulatory care visit and hospital discharge rates compared with Whites,but not mortality rates.Blacks had lower ambulatory care visit and mortality rates,but similar hospital discharge rates compared with whites.During the study period,ambulatory care and emergency department visit rates with a gallstone disease diagnosis rose,while hospital discharge and mortality rates declined.Among commercial insurance enrollees,rates were higher compared with national data for ambulatory care visits and hospitalizations,but lower for emergency department visits.Cholecystectomies performed in the United States included 605000 ambulatory laparoscopic,280000 inpatient laparoscopic,and 49000 inpatient open procedures annually.Among commercial insurance enrollees,rates were higher compared with national data for laparoscopic procedures.CONCLUSION The gallstone disease burden in the United States is substantial and increasing,particularly among women,Hispanics,and older adults with laparoscopic cholecystectomy as the mainstay treatment.Current practice patterns should be monitored for better health care access.

非生长因子依赖的MDS细胞系的建立及其生物学特性研究

本研究的目的是从骨髓增生异常综合征-慢性粒-单核细胞白血病(MDS-CMML)病人获取骨髓细胞,建立 非生长因子依赖的细胞株。该细胞株在不添加任何生长因子的含15％胎牛血清的RPMI 1640和DMEM混合培养 液中进行了培养,并分别从细胞株的形态、细胞表面抗原分子、细胞增殖、分化、凋亡等方面检测其生物学特性。结 果表明:在不添加任何生长因子的培养条件下该细胞株可以长期存活和生长,并能向单核及巨核细胞分化。结论: 成功建立了一株非生长因子依赖的MDS-JSN04(MDS-江苏南京04)细胞株,并阐明了其部分生物学特性。

Conditioned medium from human dental pulp stem cells treats spinal cord injury by inhibiting microglial pyroptosis

Human dental pulp stem cell transplantation has been shown to be an effective therapeutic strategy for spinal cord injury.However,whether the human dental pulp stem cell secretome can contribute to functional recovery after spinal cord injury remains unclear.In the present study,we established a rat model of spinal cord injury based on impact injury from a dropped weight and then intraperitoneally injected the rats with conditioned medium from human dental pulp stem cells.We found that the conditioned medium effectively promoted the recovery of sensory and motor functions in rats with spinal cord injury,decreased expression of the microglial pyroptosis markers NLRP3,GSDMD,caspase-1,and interleukin-1β,promoted axonal and myelin regeneration,and inhibited the formation of glial scars.In addition,in a lipopolysaccharide-induced BV2 microglia model,conditioned medium from human dental pulp stem cells protected cells from pyroptosis by inhibiting the NLRP3/caspase-1/interleukin-1βpathway.These results indicate that conditioned medium from human dental pulp stem cells can reduce microglial pyroptosis by inhibiting the NLRP3/caspase-1/interleukin-1βpathway,thereby promoting the recovery of neurological function after spinal cord injury.Therefore,conditioned medium from human dental pulp stem cells may become an alternative therapy for spinal cord injury.

Finding the magnetopause location using soft X-ray observations and a statistical inverse method

Variability in the location and shape of the dayside magnetopause is attributed to magnetic reconnection,a fundamental process that enables the transfer of mass,energy,and momentum from the solar wind into the magnetosphere.The spatial and temporal properties of the magnetopause,under varying solar and magnetospheric conditions,remain largely unknown because empirical studies using in-situ observations are challenging to interpret.Global wide field-of-view(FOV)imaging is the only means to simultaneously observe the spatial distribution of the plasma properties over the vast dayside magnetospheric region and,subsequently,quantify the energy transport from the interplanetary medium into the terrestrial magnetosphere.Two upcoming missions,ESA/CAS SMILE and NASA’s LEXI will provide wide-field imagery of the dayside magnetosheath in soft X-rays,an emission generated by charge exchange interactions between high charge-state heavy ions of solar wind origin and exospheric neutral atoms.High-cadence two-dimensional observations of the magnetosheath will allow the estimation of dynamic properties of its inner boundary,the magnetopause,and enable studies of its response to changes in the solar wind dynamic pressure and interplanetary magnetic field orientation.This work introduces a statistically-based estimation approach based on inverse theory to estimate the spatial distribution of magnetosheath soft X-ray emissivities and,with this,identify the location of the magnetopause over the Sun−Earth line.To do so,we simulate the magnetosheath structure using the MHD-based OpenGGCM model and generate synthetic soft X-ray images using LEXI’s orbit and attitude information.Our results show that 3-D estimations using the described statistically-based technique are robust against Poisson-distributed shot noise inherent to soft X-ray images.Also,our proposed methodology shows that the accuracy of both three-dimensional(3-D)estimation and the magnetopause standoff distance calculation highly depends on the observational point.

Mshpy23:a user-friendly,parameterized model of magnetosheath conditions

Lunar Environment heliospheric X-ray Imager(LEXI)and Solar wind−Magnetosphere−Ionosphere Link Explorer(SMILE)will observe magnetosheath and its boundary motion in soft X-rays for understanding magnetopause reconnection modes under various solar wind conditions after their respective launches in 2024 and 2025.Magnetosheath conditions,namely,plasma density,velocity,and temperature,are key parameters for predicting and analyzing soft X-ray images from the LEXI and SMILE missions.We developed a userfriendly model of magnetosheath that parameterizes number density,velocity,temperature,and magnetic field by utilizing the global Magnetohydrodynamics(MHD)model as well as the pre-existing gas-dynamic and analytic models.Using this parameterized magnetosheath model,scientists can easily reconstruct expected soft X-ray images and utilize them for analysis of observed images of LEXI and SMILE without simulating the complicated global magnetosphere models.First,we created an MHD-based magnetosheath model by running a total of 14 OpenGGCM global MHD simulations under 7 solar wind densities(1,5,10,15,20,25,and 30 cm)and 2 interplanetary magnetic field Bz components(±4 nT),and then parameterizing the results in new magnetosheath conditions.We compared the magnetosheath model result with THEMIS statistical data and it showed good agreement with a weighted Pearson correlation coefficient greater than 0.77,especially for plasma density and plasma velocity.Second,we compiled a suite of magnetosheath models incorporating previous magnetosheath models(gas-dynamic,analytic),and did two case studies to test the performance.The MHD-based model was comparable to or better than the previous models while providing self-consistency among the magnetosheath parameters.Third,we constructed a tool to calculate a soft X-ray image from any given vantage point,which can support the planning and data analysis of the aforementioned LEXI and SMILE missions.A release of the code has been uploaded to a Github repository.

Simulation of the SMILE Soft X-ray Imager response to a southward interplanetary magnetic field turning

The Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)Soft X-ray Imager(SXI)will shine a spotlight on magnetopause dynamics during magnetic reconnection.We simulate an event with a southward interplanetary magnetic field turning and produce SXI count maps with a 5-minute integration time.By making assumptions about the magnetopause shape,we find the magnetopause standoff distance from the count maps and compare it with the one obtained directly from the magnetohydrodynamic(MHD)simulation.The root mean square deviations between the reconstructed and MHD standoff distances do not exceed 0.2 RE(Earth radius)and the maximal difference equals 0.24 RE during the 25-minute interval around the southward turning.

整合mRNA转录本与基因组信息的基因组选择方法研究

基因组预测已成为畜禽、作物遗传评估和人类疾病风险预测的主要技术,但经典的基因组预测方法在性状遗传调控机制等生物学先验信息的整合方面有一定的不足。本研究提出一种将mRNA转录本信息整合应用于复杂性状表型预测的方法。基于国际上广泛应用于数量遗传学研究的果蝇群体,对本研究提出的新方法进行准确性评估。结果显示,整合mRNA转录本,可有效提高部分性状基因组预测准确性,但对部分性状的表型预测准确性没有改善。与GBLUP相比,雄性果蝇D-香芹酮嗅觉反应(dCarvone)准确性由0.256提高到0.274,提高幅度7%。雄性果蝇咖啡因耐受反应(cafe)准确性由0.355提高到0.401,提高幅度13%。雄性果蝇百草枯耐受反应(survival_paraquat)准确性由0.101提高到0.138,提高幅度36%。雌性果蝇1-已醇嗅觉反应(1hexanol)准确性由0.147提高到0.210,提高幅度43%。综上所述,对于部分性状,通过整合mRNA转录本可有效提高基因组预测准确性(提高幅度为7%~43%)。对于部分性状,整合mRNA转录本并考虑互作效应可进一步提高预测准确性。

Promising use of metformin in treating neurological disorders:biomarker-guided therapies

Neurological disorders are a diverse group of conditions that affect the nervous system and include neurodegenerative diseases(Alzheimer’s disease,multiple sclerosis,Parkinson’s disease,Huntington’s disease),cerebrovascular conditions(stroke),and neurodevelopmental disorders(autism spectrum disorder).Although they affect millions of individuals around the world,only a limited number of effective treatment options are available today.Since most neurological disorders express mitochondria-related metabolic perturbations,metformin,a biguanide type II antidiabetic drug,has attracted a lot of attention to be repurposed to treat neurological disorders by correcting their perturbed energy metabolism.However,controversial research emerges regarding the beneficial/detrimental effects of metformin on these neurological disorders.Given that most neurological disorders have complex etiology in their pathophysiology and are influenced by various risk factors such as aging,lifestyle,genetics,and environment,it is important to identify perturbed molecular functions that can be targeted by metformin in these neurological disorders.These molecules can then be used as biomarkers to stratify subpopulations of patients who show distinct molecular/pathological properties and can respond to metformin treatment,ultimately developing targeted therapy.In this review,we will discuss mitochondria-related metabolic perturbations and impaired molecular pathways in these neurological disorders and how these can be used as biomarkers to guide metformin-responsive treatment for the targeted therapy to treat neurological disorders.

The magnetosheath at high spectral resolution

While we eagerly anticipate SMILE’s(Solar wind Magnetosphere Ionosphere Link Explorer)unprecedented X-ray observations of the Earth’s magnetosheath and the initiation of a new era of magnetospheric research,it seems appropriate to look ahead to the abilities of the next generation of astrophysics missions.Of these,the Line Emission Mapper(LEM),a large aperture micro-calorimeter based mission,is currently planned to be able to observe the magnetosheath at high spectral resolution(~2 eV).With a field of view of~30′,LEM will allow higher spatial resolution and higher cadence measurement of the motion of a very small portion of the magnetopause over relatively short periods of time(multiple hours),complementing SMILE’s global mapping.LEM’s strength is its spectral resolution.It will be able to measure the abundance of a broad range of elements and ionization states,many of which are inaccessible to current in situ instruments,and will be able to separate the emission from the magnetosheath from the emission from the cosmic X-ray background using the difference in their relative velocities.

偏倚抽样问题的选择性评论及其在现代统计学中的应用

偏倚抽样是一个普遍存在的问题,跨越各个学科领域,影响着计量经济学、流行病学、医学、调查研究,以及最近的机器学习和人工智能(AI)等领域.当选择用于分析或研究的数据点引入系统性偏倚时,这种无处不在的挑战可能会影响研究结果的准确性和可靠性.本文的目标是全面介绍与偏倚抽样问题相关的基础概念和推理方法.此外,我们还旨在建立偏倚抽样问题与机器学习中关于分布转移问题的最新讨论之间的联系.我们还将深入探讨偏倚抽样的最新进展,特别是在转移学习和预测置信区间的符合推理方面.我们的最终目标是以一种对研究生易于理解的方式呈现这些材料,使他们能够在自己的研究工作中识别偏倚抽样问题的应用.我们怀着深深的敬意和感激之情,将本文献给已故的茆诗松教授,他多年来的指导和智慧对我们至关重要.

Erratum to “Plant Defense against Necrotrophic Pathogens” [American Journal of Plant Sciences 11(12) (2020) 2122-2138]

The original online version of this article (Ghozlan, M.H., EL-Argawy, E., Tokgöz, S., Lakshman, D.K. and Mitra, A. (2020) Plant Defense against Necrotrophic Pathogens. American Journal of Plant Sciences, 11, 2122-2138. https://doi.org/10.4236/ajps.2020.1112149) was published mistakenly without another co-author, Nikita Gambhir. In this regard, we revise authors and “how to cite” sections by adding her name.

Machine learning-guided accelerated discovery of structure-property correlations in lean magnesium alloys for biomedical applications

Magnesium alloys are emerging as promising alternatives to traditional orthopedic implant materials thanks to their biodegradability,biocompatibility,and impressive mechanical characteristics.However,their rapid in-vivo degradation presents challenges,notably in upholding mechanical integrity over time.This study investigates the impact of high-temperature thermal processing on the mechanical and degradation attributes of a lean Mg-Zn-Ca-Mn alloy,ZX10.Utilizing rapid,cost-efficient characterization methods like X-ray diffraction and optical microscopy,we swiftly examine microstructural changes post-thermal treatment.Employing Pearson correlation coefficient analysis,we unveil the relationship between microstructural properties and critical targets(properties):hardness and corrosion resistance.Additionally,leveraging the least absolute shrinkage and selection operator(LASSO),we pinpoint the dominant microstructural factors among closely correlated variables.Our findings underscore the significant role of grain size refinement in strengthening and the predominance of the ternary Ca_(2)Mg_(6)Zn_(3)phase in corrosion behavior.This suggests that achieving an optimal blend of strength and corrosion resistance is attainable through fine grains and reduced concentration of ternary phases.This thorough investigation furnishes valuable insights into the intricate interplay of processing,structure,and properties in magnesium alloys,thereby advancing the development of superior biodegradable implant materials.

Cloud Computing: Purpose and Future

Cloud computing is the new norm within business entities as businesses try to keep up with technological advancements and user needs. The concept is defined as a computing environment allowing for remote outsourcing of storage and computing resources. A hybrid cloud environment is an excellent example of cloud computing. Specifically, the hybrid system provides organizations with increased scalability and control over their data and support for a remote workforce. However, hybrid cloud systems are expensive as organizations operate different infrastructures while introducing complexity to the organization’s activities. Data security is critical among the most vital concerns that have resulted from the use of cloud computing, thus, affecting the rate of user adoption and acceptance. This article, borrowing from the hybrid cloud computing system, recommends combining traditional and modern data security systems. Traditional data security systems have proven effective in their respective roles, with the main challenge arising from their recognition of context and connectivity. Therefore, integrating traditional and modern designs is recommended to enhance effectiveness, context, connectivity, and efficiency.

Role of lysosomal trafficking regulator in autophagic lysosome reformation in neurons:a disease perspective

Lysosomes are discrete organelles that act as recycling centers for extracellular and intracellular materials,playing a pivotal role in maintaining cellular homeostasis.Their acidic environment,maintained by numerous hydrolytic enzymes,facilitates substrate degradation.Dysfunction in lysosomal processes can lead to abnormal substrate degradation,significantly impacting cellular homeostasis.High energy-demanding cells,such as post-mitotic neurons,are especially vulnerable to these changes,often resulting in neurological diseases.Autophagy,a conserved catabolic process,requires extensive lysosomal utilization.It plays a key role in removing unnecessary intracellular components,ensuring cellular homeostasis,and promoting cell survival during stress conditions such as starvation,infection,or cellular damage.