Characteristics and distribution of microstructures in high pressure die cast alloys with X-ray microtomography:A review

Al and Mg alloy high pressure die castings(HPDC)are increasingly used in automotive industries.The microstructures in the castings have decisive effect on the casting mechanical properties,in which the microstructure characteristics are fundamental for the investigation of the microstructure-property relation.During the past decade,the microstructure characteristics of HPDC Al and Mg alloys,especially micro-pores andα-Fe,have been investigated from two-dimensional(2D)to threedimensional with X-ray micro-computed tomography(μ-CT).This paper provides an overview of the current understanding regarding the 3D characteristics and formation mechanisms of microstructures in HPDC alloys,their spatial distributions,and the impact on mechanical properties.Additionally,it outlines future research directions for the formation and control of heterogeneous microstructures in HPDC alloys.

营养状态分级护理联合团体认知行为干预在结肠癌患者术后护理中的应用

目的:探究营养状态分级护理联合团体认知行为干预在结肠癌患者术后护理中的应用价值。方法:将2022年1月—2023年6月宜春市第二人民医院收治的80例结肠癌患者采用信封法分为对照组(40例)与研究组(40例),对照组给予常规术后护理,研究组在常规术后护理基础上联合营养状态分级护理与团体认知行为干预,共干预4周。比较干预前后两组营养状况、癌因性疲乏、心理一致感及自我管理能力变化情况。结果:干预后,研究组患者主观整体评估量表(PG-SGA)评分低于对照组,血清白蛋白(ALB)和前白蛋白(PA)水平均高于对照组,差异均有统计学意义(P<0.05)。干预后,研究组癌症疲乏量表(CFS)评分均低于对照组,中文版心理一致感量表(SOC-13)、中文版癌症自我管理效能感量表(SUPPH)评分均高于对照组,差异均有统计学意义(P<0.05)。结论:营养状态分级护理联合团体认知行为干预有利于改善结肠癌术后患者营养状况和癌因性疲乏,且对提高患者心理一致感和自我管理能力有积极意义。

Fault-tolerant FADS system development for a hypersonic vehicle via neural network algorithms

Hypersonic vehicles suffer from extreme aerodynamic heating during flights, especially around the area of leading edge due to its small curvature. Therefore, flush air data sensing(FADS) system has been developed to perform accurate measurement of the air data parameters. In the present study, the method to develop the FADS algorithms with fail-operational capability for a sharp-nosed hypersonic vehicle is provided. To be specific, the FADS system implemented with 16 airframe-integrated pressure ports is used as a case study. Numerical simulations of different freestream conditions have been conducted to generate the database for the FADS targeting in 2 ≤ Ma ≤ 5 and 0 km ≤ H ≤ 30 km. Four groups of neural network algorithms have been developed based on four different pressure port configurations, and the accuracy has been validated by 280 groups of simulations. Particularly, the algorithms based on the 16-port configuration show an excellent ability to serve as the main solver of the FADS, where 99. 5% of the angle-of-attack estimations are within the error band ±0. 2°. The accuracy of the algorithms is discussed in terms of port configuration. Furthermore, diagnosis of the system health is present in the paper. A fault-tolerant FADS system architecture has been designed, which is capable of continuously sensing the air data in the case that multi-port failure occurs, with a reduction in the system accuracy.

农业模型发展分析及应用案例

农业模型、农业人工智能及数据分析等技术贯穿于智慧农业的信息感知、信息传输、信息处理与控制全过程,是智慧农业的核心技术。为进一步明晰农业模型的内涵和作用,促进农业模型进一步研究及应用,推动智慧农业健康、稳定和可持续发展,本研究采用系统分析、比较及关系框图等方法,分析了农业模型的内涵,阐述了农业模型和智慧农业要素与过程的关系,明确了农业模型的作用并附以应用案例,比较了农业模型的国内外重要发展动态与趋势。国内外农业模型研究与应用重要进展比较表明,农业模型研究应用需要考虑农业生物要素的4个水平、农业环境要素的6个尺度、农业技术与农业经济要素的6个层次并采用相应方法进行,农业模型环境要素空间多尺度研究应用有较大发展潜力;农业模型与分子遗传学、感知技术及人工智能技术结合,农业模型研究应用的公私有组织协作,粮食安全挑战将成为农业模型进一步发展的重要推动力,且需更注重将各种农业系统模拟、数据库、和谐性与开放数据及决策支持系统相连接。中国农业模型研究与应用已形成具有中国特色的作物模型系列,也融入农业模型的互比较与改进、智慧农业等世界潮流,需要抢抓机遇,加快发展。农业模型是农业系统要素内及要素间关系的定量化表达,是农业科学定量与综合的重要方法,具有认识论价值,它与感知技术的结合可以在智慧农业数据获取与处理中发挥不可或缺的作用,成为信息农业技术落地应用的重要桥梁和纽带。

磁共振氘代谢成像研究进展综述

分子代谢异常是肿瘤和神经退行性疾病等重大疾病的标志性特征。无创反映活体内细胞分子代谢特征对于了解肿瘤和神经退行性疾病等重大疾病的发病机制、制定疾病治疗方案和监测疾病进展至关重要。目前,能用于人体临床的分子代谢成像主要依赖于正电子发射型计算机断层显像技术(PET)或磁共振波谱技术(MRS)。磁共振氘(^(2)H)代谢成像(DMI)技术是近年来兴起的一种分子代谢成像手段,机体摄入^(2)H标记的探针后,通过磁共振波谱成像技术检测^(2)H标记探针以及它们的下游代谢产物,实现代谢流的定量检测。与PET技术相比,它不仅能够反映机体对探针的摄取,还能提供了更多代谢下游的细节,无电离辐射且易于实施。最近的研究显示磁共振^(2)H代谢成像技术在肿瘤和神经退行性疾病上具有极大的临床应用价值。本篇综述回顾了^(2)H作为代谢示踪剂的历史与磁共振^(2)H代谢成像的特点,介绍了磁共振^(2)H代谢成像的最新研究进展,并对该技术的应用前景进行展望。

国家基因库：共有、共为、共享

基因资源是国家的重要战略资源,保存、保护和合理利用基因资源将成为未来维护国家安全、打造核心竞争力的坚实基础和有效保障,然而我国在基因数据存储、样本存储等方面均起步较晚,无法满足国内日益增长的生命科学相关领域的研究发展需求。针对上述问题,2011年中国政府批复依托深圳华大生命科学研究院(原深圳华大基因研究院)建设我国首个读、写、存一体化的综合性生物遗传资源基因库深圳国家基因库(亦称国家基因库)。本文总结了国内外较有影响力的基因资源大平台的发展概况,着重阐述了国家基因库的定位与使命,以及“三库两平台”的结构与功能生物遗传资源的存储、读取、合成运用和开放共享。自2016年9月正式运行以来,国家基因库作为公益性、开放性、支撑性、引领性的战略性科技平台,已具备千万级可溯源样本存储能力,十万级基因组/年的存储和计算能力,建成首个国产化Pb(Petabases)级基因组数据产出平台以及千万碱基/年高效合成平台,同时基于自身平台能力,国家基因库建立了全面的开放共享机制,开展资源数据共享和公共平台服务,对生命科学研究和生物产业创新发展的支撑和助力初见成效。

Molecular analysis of the chloroplast Cu/Zn-SOD gene(AhCSD2) in peanut

Superoxide dismutase(SOD, EC 1.15.1.1) plays a key role in response to drought stress, and differences in SOD activity changes among cultivars are important under drought conditions. We obtained the full-length DNA of the chloroplast Cu/Zn-SOD gene(Ah CSD2)from 11 allotetraploid cultivars and 5 diploid wild species in peanut. BLAST search against the peanut genome showed that the Ah CSD2 genes g CSD2-1 and g CSD2-2 are located at the tops of chromosome A03(A genome) and B03(B genome), respectively, and both contain 8exons and 7 introns. Nucleotide sequence analyses indicated that g CSD2-2 sequences were identical among all the tested cultivars, while g CSD2-1 sequences showed allelic variations.The amino acid sequences deduced from g CSD2-1 and g CSD2-2 both contain a chloroplast transit peptide and are distinguished by 6 amino acid(aa) residue differences. The other 2aa residue variations in the mature peptide regions give rise to three-dimensional structure changes of the protein deduced from the genes g CSD2-1 and g CSD2-2. Sequences analyses of cultivars and wild species showed that g CSD2-2 of Arachis hypogaea and g Aip CSD2(Arachis ipaensis) are identical, and despite the abundant polymorphic loci between g CSD2-1 of A.hypogaea and sequences from A genome wild species, the deduced amino acid sequence of Ah CSD2-1(A. hypogaea) is identical to that of Adu CSD2(Arachis duranensis), whereas Aco CSD2(Arachis correntina) and Aca CSD2(Arachis cardenasii) both have 2 aa differences in the transit peptide region compared with Ah CSD2-1(A. hypogaea). Based on the Peanut Genome Project, promoter prediction revealed many stress-related cis-acting elements within the potential promoter regions(pp-A and pp-B). pp-A contains more binding sites for drought-associated transcriptional factors than pp-B. We hypothesize that the marked changes in SOD activity in different cultivars under drought stress are tightly regulated by transcription factors through transcription and expression of Ah CSD2 genes.

Low intensity near-infrared light promotes bone regeneration via circadian clock protein cryptochrome 1

Bone regeneration remains a great clinical challenge. Low intensity near-infrared(NIR) light showed strong potential to promote tissue regeneration, offering a promising strategy for bone defect regeneration. However, the effect and underlying mechanism of NIR on bone regeneration remain unclear. We demonstrated that bone regeneration in the rat skull defect model was significantly accelerated with low-intensity NIR stimulation. In vitro studies showed that NIR stimulation could promote the osteoblast differentiation in bone mesenchymal stem cells(BMSCs) and MC3T3-E1 cells, which was associated with increased ubiquitination of the core circadian clock protein Cryptochrome 1(CRY1) in the nucleus. We found that the reduction of CRY1 induced by NIR light activated the bone morphogenetic protein(BMP) signaling pathways, promoting SMAD1/5/9 phosphorylation and increasing the expression levels of Runx2 and Osterix. NIR light treatment may act through sodium voltage-gated channel Scn4a, which may be a potential responder of NIR light to accelerate bone regeneration. Together, these findings suggest that low-intensity NIR light may promote in situ bone regeneration in a CRY1-dependent manner, providing a novel, efficient and non-invasive strategy to promote bone regeneration for clinical bone defects.

Interfacial-Strain-Induced Structural and Polarization Evolutions in Epitaxial Multiferroic BiFeO_3(001) Thin Films

Varying the film thickness is a precise route to tune the interfacial strain to manipulate the properties of the multiferroic materials.Here,to explore the effects of the interfacial strain on the properties of the multiferroic BiFeO_3films,we investigated thickness-dependent structural and polarization evolutions of the BiFeO_3 films.The epitaxial growth with an atomic stacking sequence of BiO/TiO_2 at the interface was confirmed by scanning transmission electron microscopy.Combining X-ray diffraction experiments and first-principles calculations,a thickness-dependent structural evolution was observed from a fully strained tetragonality to a partially relaxed one without any structural phase transition or rotated twins.The tetragonality(c/a) of the BiFeO_3 films increases as the film thickness decreases,while the polarization is in contrast with this trend,and the size effect including the depolarization field plays a crucial role in this contradiction in thinner films.These findings offer an alternative strategy to manipulate structural and polarization properties by tuning the interfacial strain in epitaxial multiferroic thin films.

Exploring the Far Side of Glycosyl Sulfoxide Activation Process

The discovery of Kahne glycosylation forwards a big step in the carbohydrate chemistry.Despite an extensive series of studies,the precise mechanism of this powerful glycosylation is still not fully understood.To address these 30-year puzzles,the far side of Kahne glycosylation is explored in this study.After a series of control and tracking experiments,a number of important intermediates including glycosyl oxo-sulfonium ion and sulfenic anhydride(Crich's intermediate)are suggested to be responsible for the complex reaction pathway.It also reveals that in addition to the conventional ionic glycosylation pathway,a novel free radical pathway is very likely to contribute to the various side-and co-products.This study provides further understanding of Kahne glycosylation,and it also sheds light on how to improve the efficiency of sulfoxide-based glycosylation reactions.

外资企业的退出市场行为--经济发展还是劳动力市场价格管制?

本文利用我国制造业企业数据库,研究了地区经济发展与最低工资对外资企业退出市场行为的影响。估计结果显示,地区经济发展水平并不影响外资企业退出市场行为;而最低工资从25分位数提高至75分位数时,能解释样本期间外资企业退出概率平均值的20%。相比"市场导向型"外资企业,"成本导向型"外资企业更容易因为最低工资提高而退出市场:劳动密集度高、规模越大、平均工资低、所在行业低技能劳动力占比高、行业竞争激烈程度较高、产业配套条件较差的行业中的企业更容易受到最低工资上升的不利影响。

SCNN1B and CA12 play vital roles in occurrence of congenital bilateral absence of vas deferens(CBAVD)

Dear Editor,Congenital bilateral absence of the vas deferens(CBAVD),a complete or partial defect of the Wolffian duct derivatives,is found in>25% of men with obstructive azoospermia(OA),but the underlying pathological mechanism remains poorly understood.Previous research has shown that the most common disease associated with CBAVD is cystic fibrosis(CF),the predominant manifestations of which include progressive lung disease,pancreatic dysfunction,elevated sweat chloride electrolyte,meconium ileus,and male infertility.

Recent progress on the synthesis of 2-deoxy glycosides

2-Deoxy glycosides are widely presented in natural products and clinical reagents.The presence of 2-deoxy glycosides is essential for bioactivities of these compounds.This report provides an overview of the recent advances in the stereoselective synthesis of 2-deoxy glycosides.Particularly,the contents of this review covered the work published since the earlier reviews on this topic by Marzabadi(2000),Lowary(2009),Ding(2012) and Nagorny(2012).

Dynamic separation of Xe and Kr by metal-organic framework and covalent-organic materials： a comparison with activated charcoal

We systematically investigate dynamic separation of Xe and Kr at room temperature using four representative porous materials(Cu-BTC, ZIF-8, COP-4 and activated carbon(AC)). Results indicate that among the four materials, Cu-BTC not only shows the highest retention volume per gram(V_g=788 m L g^(-1), which is 1.8 times of activated carbon(436 m L g^(-1))) under flowing condition, but also can separate 350 ppm Xe from 35 ppm Kr mixture in air with a high Xe/Kr selectivity of 8.6 at room temperature and 200 k Pa, due to its suitable pore morphology, open metal sites, small side pockets in the framework. Moreover, the Cu-BTC also performs well on individual separation of Xe, Kr, CO_2 from five-component gas mixture(Xe:Kr:CO_2:Ar:N_2= 1:1:1:1:0.5, V/V) and has the longest retention time for Xe(20 min) in gas chromatographic separation, suggesting that it is a good candidate for potential applications as polymeric sieves.

Transfer learning for deep neural network-based partial differential equations solving

Deep neural networks(DNNs)have recently shown great potential in solving partial differential equations(PDEs).The success of neural network-based surrogate models is attributed to their ability to learn a rich set of solution-related features.However,learning DNNs usually involves tedious training iterations to converge and requires a very large number of training data,which hinders the application of these models to complex physical contexts.To address this problem,we propose to apply the transfer learning approach to DNN-based PDE solving tasks.In our work,we create pairs of transfer experiments on Helmholtz and Navier-Stokes equations by constructing subtasks with different source terms and Reynolds numbers.We also conduct a series of experiments to investigate the degree of generality of the features between different equations.Our results demonstrate that despite differences in underlying PDE systems,the transfer methodology can lead to a significant improvement in the accuracy of the predicted solutions and achieve a maximum performance boost of 97.3%on widely used surrogate models.

Hepatocellular carcinoma in Hepatitis B and Human Immunodeficiency Virus coinfection in Africa:a focus on surveillance

Human immunodeficiency virus(HIV)and hepatitis-B virus(HBV)infections are weighty public health challenges,especially in the African continent.The direct carcinogenic effect of HBV means that it remains a potent cause of early-onset hepatocellular carcinoma(HCC)in Sub-Saharan Africa(SSA),where it causes significant morbidity and mortality.The presence of HIV infection in HBV-infected patients poses a complicating factor,as coinfection has been shown to hasten the progression of liver disease to cirrhosis and HCC,and often resulting in early-age hepatocarcinogenesis with consequent late diagnosis and lower survival.In this review,we discuss this unique conundrum,the epidemiology of HIV-HBV coinfection in SSA,its effect on liver disease and development of HCC,as well as practices and barriers to HCC surveillance in this distinct population.We propose a way forward to curb this considerable health burden focusing on reduction of disease stigma,the need for easy-to-measure biomarkers,and implementation of large prospective studies in this population.

Ag_(2)O/squaramide cocatalyzed asymmetric interrupted Barton-Zard reaction of 8-nitroimidazo[1,2-a]pyridines

Imidazo[1,2-a]pyridines are present in numerous biologically active compounds as the core structural motif.Herein,we report an asymmetric interrupted Barton-Zard reaction of electron-deficient imidazo[1,2-a]pyridines withα-substituted isocyanoacetates.The reaction enables the dearomatization of 8-nitroimidazo[1,2-a]pyridines and hence offers straightforward access to an array of optically active highly functionalized imidazo[1,2-a]pyridine derivatives that possess three contiguous stereogenic centers in good yields(up to 98%)with high stereoselectivities(>19:1 dr,>99%ee).It is worth noting that the catalytic system consisting of a chiral squaramide and silver oxide displays remarkable reactivity and stereoselectivity,and a gram-scale reaction is compatible with the catalyst loading of 0.5 mol%.In addition,the synthetic potential of this method was showcased by versatile transformations of the product.

Togni-ⅡReagent Mediated Selective Hydrotrifluoromethylation and Hydrothiolation of Alkenes

Based on the redox reactions of Togni-Ⅱreagent and thiols,a thiol-tuned selective functionalization of unactivated olefins was disclosed.In combination with aryl thiols,stoichiometric amount of Togni-Ⅱreagent prompted a hydrotrifluoromethylation of alkenes,in which,aryl thiols played as reductant and hydrogen source;while by utilization of alkyl thiols,catalytic amount of Togni-Ⅱreagent initiated thiol-ene and thiol-yne reactions.The reported applications are characterized by their operational simplicity and wide functional group tolerance.

Application of Novel Design Bone Grafting for Treatment of Segmental Acetabular Rim Defects During Revision Total Hip Arthroplasty

The study aimed to develop efficient techniques with different novel graft structures to enhance the treatment of acetabular bone deficiency.The inhomogeneous material properties Finite Element Analysis(FEA)model was reconstructed according to computed tomography images based on a healthy patient without any peri-acetabular bony defect according to the American Academy of Orthopedic Surgeons(AAOS).The FEA model of acetabular bone deficiency was performed to simulate and evaluate the mechanical performances of the grafts in different geometric structures,with the use of fixation implants(screws),along with the stress distribution and the relative micromotion of graft models.The stress distribution mainly concentrated on the region of contact of the screws and superolateral bone.Among the different structures,the mortise-tenone structure provided better relative micromotion,with suitable biomechanical property even without the use of screws.The novel grafting structures could provide sufficient biomechanical stability and bone remodeling,and the mortise-tenone structure is the optimal treatment option for acetabulum reconstruction.

Optical spectroscopy study of charge density wave orderOptical spectroscopy study of charge density wave order in Sr_3Rh_4Sn_(13) and (Sr_(0.5)Ca_(0.5))3_Rh_4Sn_(13)

The ultrafast laser-excited magnetization dynamics of ferromagnetic （FM） La0.67Sr0.33MnO3 （LSMO） thin films with BiFeO3 （BFO） coating layers grown by laser molecular beam epitaxy are investigated using the optical pump-probe technique. Uniform magnetization precessions are observed in the films under an applied external magnetic field by measuring the time-resolved magneto-optical Kerr effect. The magnetization precession frequencies of the LSMO thin films with the BFO coating layers are lower than those of uncoated LSMO films, which is attributed to the suppression of the anisotropy field induced by the exchange interaction at the interface between the antiferromagnetic order of BFO and the FM order of LSMO.