Preparation,properties,and applications of Bi_(2)O_(2)Se thin films:A review

Two-dimensional materials have shown great application potential in high-performance electronic devices because they are ultrathin,have an ultra-large specific surface area,high carrier mobility,efficient channel current regulation,and extraordinary integration.In addition to graphene,other types of 2D nanomaterials have also been studied and applied in photodetectors,solar cells,energy storage devices,and so on.Bi_(2)O_(2)Se is an emerging 2D semiconductor material with very high electron mobility,modest bandgap,near-ideal subthreshold swing,and excellent thermal and chemical stability.Even in a monolayer structure,Bi_(2)O_(2)Se has still exhibited efficient light absorption.In this mini review,the latest main research progresses on the preparation methods,electric structure,and the optical,mechanical,and thermoelectric properties of Bi_(2)O_(2)Se are summarized.The wide rang of applications in electronics and photoelectronic devices are then reviewed.This review concludes with a discussion of the existing open questions/challenges and future prospects for Bi_(2)O_(2)Se.

Activation of G-protein-coupled receptor 39 reduces neuropathic pain in a rat model

Activated G-protein-coupled receptor 39(GPR39)has been shown to attenuate inflammation by interacting with sirtuin 1(SIRT1)and peroxisome proliferator-activated receptor-γcoactivator 1α(PGC-1α).However,whether GPR39 attenuates neuropathic pain remains unclear.In this study,we established a Sprague-Dawley rat model of spared nerve injury-induced neuropathic pain and found that GPR39 expression was significantly decreased in neurons and microglia in the spinal dorsal horn compared with sham-operated rats.Intrathecal injection of TC-G 1008,a specific agonist of GPR39,significantly alleviated mechanical allodynia in the rats with spared nerve injury,improved spinal cord mitochondrial biogenesis,and alleviated neuroinflammation.These changes were abolished by GPR39 small interfering RNA(siRNA),Ex-527(SIRT1 inhibitor),and PGC-1αsiRNA.Taken together,these findings show that GPR39 activation ameliorates mechanical allodynia by activating the SIRT1/PGC-1αpathway in rats with spared nerve injury.

Screening the optimal Co_(x)/CeO_(2)(110)(x=1–6)catalyst for methane activation in coalbed gas

The challenges posed by energy and environmental issues have forced mankind to explore and utilize unconventional energy sources.It is imperative to convert the abundant coalbed gas(CBG)into high value-added products,i.e.,selective and efficient conversion of methane from CBG.Methane activation,known as the“holy grail”,poses a challenge to the design and development of catalysts.The structural complexity of the active metal on the carrier is of particular concern.In this work,we have studied the nucleation growth of small Co clusters(up to Co_(6))on the surface of CeO_(2)(110)using density functional theory,from which a stable loaded Co/CeO_(2)(110)structure was selected to investigate the methane activation mechanism.Despite the relatively small size of the selected Co clusters,the obtained Co_(x)/CeO_(2)(110)exhibits interesting properties.The optimized Co_(5)/CeO_(2)(110)structure was selected as the optimal structure to study the activation mechanism of methane due to its competitive electronic structure,adsorption energy and binding energy.The energy barriers for the stepwise dissociation of methane to form CH3^(*),CH2^(*),CH^(*),and C^(*)radical fragments are 0.44,0.55,0.31,and 1.20 eV,respectively,indicating that CH^(*)dissociative dehydrogenation is the rate-determining step for the system under investigation here.This fundamental study of metal-support interactions based on Co growth on the CeO_(2)(110)surface contributes to the understanding of the essence of Co/CeO_(2) catalysts with promising catalytic behavior.It provides theoretical guidance for better designing the optimal Co/CeO_(2) catalyst for tailored catalytic reactions.

Assessment of causal effects of physical activity on neurodegenerative diseases:A Mendelian randomization study

Background:Physical activity has been hypothesized to play a protective role in neurodegenerative diseases.However,effect estimates previously derived from observational studies were prone to confounding or reverse causation.Methods:We performed a two-sample Mendelian randomization(MR)analysis to explore the causal association of accelerometer-measured physical activity with 3 common neurodegenerative diseases:Alzheimer’s disease(AD),Parkinson’s disease(PD),and amyotrophic lateral sclerosis(ALS).We selected genetic instrumental variants reaching genome-wide significance(p<5×10^(-8))from 2 largest meta-analyses of about 91,100 UK Biobank participants.Summary statistics for AD,PD,and ALS were retrieved from the up-to-date studies in European ancestry led by the international consortia.The random-effect,inverse-variance weighted MR was employed as the primary method,while MR pleiotropy residual sum and outlier(MR-PRESSO),weighted median,and MR-Egger were implemented as sensitivity tests.All statistical analyses were performed using the R programming language(Version 3.6.1;R Foundation for Statistical Computing,Vienna,Austria).Results:Primary MR analysis and replication analysis utilized 5 and 8 instrumental variables,which explained 0.2%and 0.4%variance in physical activity,respectively.In each set,one variant at 17q21 was significantly associated with PD,and MR sensitivity analyses indicated them it as an outlier and source of heterogeneity and pleiotropy.Primary results with the removal of outlier variants suggested odds ratios(ORs)of neurodegenerative diseases per unit increase in objectively measured physical activity were 1.52 for AD(95%confidence interval(95%CI):0.88-2.63,p=0.13)and 3.35 for PD(95%CI:1.32-8.48,p=0.01),while inconsistent results were shown in the replication set for AD(OR=1.06,95%CI:1.01-1.12,p=0.02)and PD(OR=0.99,95%CI:0.88-0.12,p=0.97).Similarly,the beneficial effect of physical activity on ALS(OR=0.51,95%CI:0.29-0.91,p=0.02)was not confirmed in the replication analysis(OR=0.96,95%CI:0.91-1.02,p=0.22).Conclusion:Genetically predicted physical activity was not robustly associated with risk of neurodegenerative disorders.Triangulating evidence across other studies is necessary in order to elucidate whether enhancing physical activity is an effective approach in preventing the onset of AD,PD,or ALS.

Non-Singular Trees, Unicyclic Graphs and Bicyclic Graphs

We called graph G non-singular if adjacency matrix A (G) of G is non-singular. A connected graph with n vertices and n-1, n and n+1 edges are called the tree, the unicyclic graph and the bicyclic graph. Respectively, as we all know, each connected bicyclic graph must contain ∞(a,s,b) or?θ(p,l,q) as the induced subgraph. In this paper, by using three graph transformations which do not change the singularity of the graph, the non-singular trees, unicyclic graphs and bicyclic graphs are obtained.

Electrocatalytic synthesis of C-N coupling compounds from CO_(2) and nitrogenous species

The electrocatalytic synthesis of C-N coupling compounds from CO_(2) and nitrogenous species not only offers an effective avenue to achieve carbon neutral-ity and reduce environmental pollution,but also establishes a route to synthesize valuable chemicals,such as urea,amide,and amine.This innovative approach expands the application range and product categories beyond simple carbona-ceous species in electrocatalytic CO_(2) reduction,which is becoming a rapidly advancing field.This review summarizes the research progress in electrocatalytic urea synthesis,using N_(2),NO_(2)^(-),and NO_(3)^(-)as nitrogenous species,and explores emerging trends in the electrosynthesis of amide and amine from CO_(2) and nitro-gen species.Additionally,the future opportunities in this field are highlighted,including electrosynthesis of amino acids and other compounds containing C-N bonds,anodic C-N coupling reactions beyond water oxidation,and the catalytic mechanism of corresponding reactions.This critical review also captures the insights aimed at accelerating the development of electrochemical C-N coupling reactions,confirming the superiority of this electrochemical method over the traditional techniques.

BIFURCATION ANALYSIS IN A PREDATOR-PREY MODEL WITH AN ALLEE EFFECT AND A DELAYED MECHANISM

Regarding delay-induced predator-prey models, much research has been done on delayed destabilization, but whether delays are stabilizing or destabilizing is a subtle issue. In this study, we investigate predator-prey dynamics affected by both delays and the Allee effect. We analyze the consequences of delays in different feedback mechanisms. The existence of a Hopf bifurcation is studied, and we calculate the value of the delay that leads to the Hopf bifurcation. Furthermore, applying the normal form theory and a center manifold theorem, we consider the direction and stability of the Hopf bifurcation. Finally, we present numerical experiments that validate our theoretical analysis. Interestingly, depending on the chosen delay mechanism, we find that delays are not necessarily destabilizing. The Allee effect generally increases the stability of the equilibrium, and when the Allee effect involves a delay term, the stabilization effect is more pronounced.

Comparative assessment of nitrogen fixation rate by ^(15)N_(2) tracer assays in the South China Sea

Nitrogen fixation is one of the most important sources of new nitrogen in the ocean and thus profoundly affects the nitrogen and carbon biogeochemical processes.The distribution,controlling factors,and flux of N2 fixation in the global ocean remain uncertain,partly because of the lack of methodological uniformity.The^(15)N_(2)tracer assay(the original bubble method→the^(15)N_(2)-enriched seawater method→the modified bubble method)is the mainstream method for field measurements of N2 fixation rates(NFRs),among which the original bubble method is the most frequently used.However,accumulating evidence has suggested an underestimation of NFRs when using this method.To improve the availability of previous data,we compared NFRs measured by three^(15)N_(2)tracer assays in the South China Sea.Our results indicate that the relationship between NFRs measured by the original bubble method and the^(15)N_(2)-enriched seawater method varies obviously with area and season,which may be influenced by incubation time,diazotrophic composition,and environmental factors.In comparison,the relationship between NFRs measured by the original bubble method and the modified bubble method is more stable,indicating that the N2 fixation rates based on the original bubble methods may be underestimated by approximately 50%.Based on this result,we revised the flux of N2 fixation in the South China Sea to 40 mmol/(m2·a).Our results improve the availability and comparability of literature NFR data in the South China Sea.The comparison of the^(15)N_(2)tracer assay for NFRs measurements on a larger scale is urgently necessary over the global ocean for a more robust understanding of the role of N2 fixation in the marine nitrogen cycle.

肺癌患者恶病质的药物治疗与营养支持研究进展

恶病质是肺癌患者的一种常见并发症,它会加重化疗毒副作用、阻碍治疗计划、削弱化疗反应性、降低生活质量,增加并发症及死亡率,严重危害肺癌患者的生理、心理健康。肿瘤恶病质的发病原因与发病机制都极为复杂,使其治疗具有艰巨性与复杂性。控制肺癌患者的恶病质需要采取抗肿瘤治疗、抑制炎症反应、营养支持、体育锻炼、缓解症状等多种手段,发挥多模式治疗的协同作用对抗肿瘤恶病质的多种机制。迄今为止,学科内已就任何单一疗法都不能控制恶病质的发生发展达成了一致共识。有些疗法取得了一定的研究进展,但需要在充分评估肺癌患者个体特征后结合多模式治疗实施。本文重点综述了肿瘤恶病质的药物治疗与营养支持等干预方法在肺癌患者人群中的应用,并对肺癌患者恶病质控制的研究方向进行展望。

Progress and key challenges in catalytic combustion of lean methane

As a primary type of clean energy,methane is also the second most important greenhouse gas after CO_(2)due to the high global warming potential.Large quantities of lean methane(0.1–1.0 vol%)are emitted into the atmosphere without any treatment during coal mine,oil,and natural gas production,thus leading to energy loss and greenhouse effect.In general,it is challenging to utilize lean methane due to its low concentration and flow instability,while catalytic combustion is a vital pathway to realize an efficient utilization of lean methane owing to the reduced emissions of polluting gases(e.g.,NOxand CO)during the reaction.In particular,to efficiently convert lean methane,it necessitates both the designs of highly active and stable heterogeneous catalysts that accelerate lean methane combustion at low temperatures and smart reactors that enable autothermal operation by optimizing heat management.In this review,we discuss the in-depth development,challenges,and prospects of catalytic lean methane combustion technology in various configurations,with particular emphasis on heat management from the point of view of material design combined with reactor configuration.The target is to describe a framework that can correlate the guiding principles among catalyst design,device innovation and system optimization,inspiring the development of groundbreaking combustion technology for the efficient utilization of lean methane.

抗血管生成治疗联合免疫检查点抑制剂在实体瘤治疗中的研究进展

免疫检查点抑制剂是近年来肿瘤治疗领域的热点,虽然在多种肿瘤中取得了显著的疗效,但仍存在原发耐药与继发耐药的问题。为了进一步提高免疫检查点抑制剂的疗效、克服耐药问题,目前基于免疫微环境调控机制的多项研究将抗血管生成药物与免疫检查点抑制剂联合进行深入的探索。抗血管生成药物联合免疫治疗在多种实体瘤中表现出显著的疗效和生存获益。其中抗血管生成治疗使血管正常化的同时重塑肿瘤免疫微环境,免疫检查点抑制剂不仅通过阻断负性免疫调节信号,增强宿主抗肿瘤免疫反应,而且可以促进血管正常化。本文对抗血管生成药物联合免疫检查点抑制剂治疗实体瘤的相关基础及临床研究文献进行综述。

硫醇化合物/月桂酸对废胶粉精准脱硫的影响及机理

利用硫醇化合物/月桂酸复合脱硫剂,通过双螺杆熔融挤出法对废胶粉进行精准脱硫。采用渗透凝胶色谱、扫描电镜、差示扫描量热和红外光谱等研究了复合脱硫剂对脱硫橡胶脱硫效果的影响。结果表明,复合脱硫剂的最佳脱硫工艺为:使用质量分数10%软化组分(糠醛抽出油)、5%脱硫组分(硫醇化合物)与5%促进组分(月桂酸),以220℃的脱硫温度对废胶粉进行精准脱硫,脱硫后的试样的溶胶含量可达到70.1%、相对分子质量为13105。复合脱硫剂中的糠醛抽出油可以促使废胶粉溶胀,硫醇化合物中的巯基能精准作用于C-S,S-S和多S键并使其断裂,月桂酸通过润滑作用可促进脱硫反应的进行,三者复合后的脱硫剂能够实现废胶粉的精准脱硫。

术后辅助化疗在消化道神经内分泌癌中的临床研究

目的:消化道神经内分泌癌(neuroendocrine carcinomas,NECs)是一种罕见的侵袭性肿瘤。对于无远处转移的患者,可选择根治性手术,但术后易出现复发转移,预后差。术后辅助化疗在NECs中的疗效尚不明确,缺乏相关临床研究数据,无标准治疗方案。本研究观察接受根治性手术的消化道NECs患者接受术后辅助化疗对比单纯手术与生存的相关性。方法:回顾性分析2018年6月至2020年9月于郑州大学附属肿瘤医院接受根治手术的消化道NECs患者的临床病理资料。根据是否接受术后辅助化疗分为辅助化疗组和单纯手术组。辅助化疗组于术后4~6周开始接受至少2个周期以铂类为基础的化疗。主要研究终点为2年无病生存率(disease-free survival,DFS),次要研究终点为不同辅助化疗方案DFS。结果:共筛选62例患者,其中男性52例(83.9%),女性10例(16.1%),中位年龄为65(38~84)岁。食管NECs为12例(19.3%),胃NECs为45例(72.6%),小肠和结直肠NECs为5例(8.1%)。38例(61.3%)患者接受了术后辅助化疗,其中21例采用依托泊苷联合铂类(EP)方案化疗,17例采用伊立替康联合铂类(IP)方案化疗。21例患者术后辅助治疗超过4个周期。24例(38.7%)患者接受了单纯手术治疗。术后辅助化疗组和单纯手术组2年DFS分别为58.7%和14.7%(P<0.001)。多因素分析提示,对于淋巴结阳性的患者接受术后辅助化疗可明显提高生存获益(HR:6.403,95%CI:1.329~27.465,P=0.020)。结论:在可切除的消化道NECs中,术后辅助化疗可降低术后复发转移风险,提高患者的无病生存获益,但辅助化疗方案的选择仍需进行深入的研究。

Suppressing byproduct formation for high selective CO_(2) reduction over optimized Ni/TiO_(2) based catalysts

One of the challenges for catalytic CO_(2)reduction is to control product selectivity,and new findings that can modify selectivity would be transformative.Herein,two kinds of TiO_(2)(homemade and commercial)with the same crystal phase but different surface properties are chosen as supports to prepare Ni-based catalysts for CO_(2)reduction,which show distinctly different product selectivity for CO_(2)reduction to CH_(4) or CO,as well as the CO_(2)conversion.The catalysts based on the homemade TiO_(2)support are highly selective for CH_(4) formation,while the latter ones are about 100%selective for CO formation under the same reaction conditions.In addition,the former ones are much active(more than 3 times)than the latter ones.We found that the collaborative contribution of Ti^(3+)and Ni^(2+)species and the electronic metal-support interactions effect maybe the main driving force behind for determining the product selectivity.Methane is almost exclusively produced over the catalysts with abundant Ti^(3+)and Ni^(2+)species and greater electronic metal-support interaction,otherwise,it will give priority to CO generation.The addition of CeO_(2)can reduce the Ni particle size and improve the dispersion of Ni nanoparticles,as well as create more Ti^(3+)species,contributing to the enhancement of CO_(2)conversion,but shows a negligible effect on product selectivity.Furthermore,the in situ DRIFT experiments and kinetic experiments indicate that the CO route is probably involved in the CO_(2)reduction process over the homemade Ni-CeO_(2)/TiO_(2)-CO catalyst with abundant Ti^(3+)and Ni^(2+)species and a strong electronic transform effect.

Graphs with Pendant Vertices and <i>r</i>(<i>G</i>) &#8804;7

Let G be a graph of order n with vertex set V(G) = {v1, v2,…, vn}. the adjacency matrix of G is an n × n matrix A(G) = (aij)n×n, where aij is the number edges joining vi and vj in G. The eigenvalues λ1, λ2, λ3,…, λn, of A(G) are said to be the eigenvalues of the graph G and to form the spectrum of this graph. The number of nonzero eigenvalues and zero eigenvalues in the spectrum of G are called rank and nullity of the graph G, and are denoted by r(G) and η(G), respectively. It follows from the definitions that r(G) + η(G) = n. In this paper, by using the operation of multiplication of vertices, a characterization for graph G with pendant vertices and r(G) = 7 is shown, and then a characterization for graph G with pendant vertices and r(G) less than or equal to 7 is shown.

Study on Endoscopic Treatment of Non-Varicose Upper Gastrointestinal Bleeding

Upper gastrointestinal bleeding is a common clinical disease with a relatively high incidence rate,and it is also an acute bleeding disease with a greater impact.If not rescued in time,it will greatly threaten the patient's physical and mental health and may even be fatal,especially in cases of non-varicose upper hemorrhage,which is closely related to digestive ulcers.In most cases,related diseases are selflimiting-However,some of the cases are relatively urgent and require internal meridian treatment to promote coagulation and improve existing disease situation.For endoscopic treatment process,related treatment methods have certain specificities,and their characteristics need to be fully understood.

In-situ solid-phase anion-exchange full-color perovskite light-emitting devices

Perovskite materials can realize the transition from green light to full-visible light spectrum by halogen anion exchange.Here,we designed an in-situ solid-phase anion-exchange method combined with inkjet printing to achieve full-color perovskite quantum dot light-emitting diodes(PeQD-LEDs).It was revealed that,in addition to the concentration,the anion-exchange rate was affected by the dielectric constant of the anion-exchange medium solvent.Without destroying the PeQD film,the higher the dielectric constant of the solvent,the faster the reaction rate.And at the same time,the solvent with higher dielectric constant will cause more defects,so the morphology,structure and properties of the perovskite films varied with solvents.The chain length of amine salts in anion-exchange medium solute also played a key role in the stability of electroluminescence spectra.The obtained blue-light devices had a maximum EQE of 4.6%at 481 nm and 6.6%at 493 nm prepared by spin-coating.For inkjet printing,instead of printing red-,green-and blue-luminescent materials,we printed halogen-containing materials to achieve the in-situ solid-phase anion-exchange with underlying Pe QDs,and the inkjet-printed full-color device showed the current efficiency of 0.78 cd A^(-1).The method to achieve full-color devices by inkjet-printing halogen-containing materials can not only simplify the process,but also broaden the range of material selection,making the ink preparation more selective.

From Coarse to Fine:Two-Stage Indoor Localization with Multisensor Fusion

Increasing attention has been paid to high-precision indoor localization in dense urban and indoor environments.Previous studies have shown single indoor localization methods based on WiFi fingerprints,surveillance cameras or Pedestrian Dead Reckoning(PDR)are restricted by low accuracy,limited tracking region,and accumulative error,etc.,and some defects can be resolved with more labor costs or special scenes.However,requesting more additional information and extra user constraints is costly and rarely applicable.In this paper,a two-stage indoor localization system is presented,integrating WiFi fingerprints,the vision of surveillance cameras,and PDR(the system abbreviated as iWVP).A coarse location using WiFi fingerprints is done advanced,and then an accurate location by fusing data from surveillance cameras and the IMU sensors is obtained.iWVP uses a matching algorithm based on motion sequences to confirm the identity of pedestrians,enhancing output accuracy and avoiding corresponding drawbacks of each subsystem.The experimental results show that the iWVP achieves high accuracy with an average position error of 4.61 cm,which can effectively track pedestrians in multiple regions in complex and dynamic indoor environments.

Human RNA Modifications Disease Database(HRMDD):A web resource for the molecular and clinical landscape of RNA modifications in human diseases

Here,we developed a comprehensive web-searchable database,designated as Human RNA Modifications Disease Database(HRMDD,http://bio-bigdata.hrbmu.edu.cn/HRMDD/home.jsp).RNA modification(RM)is an important mechanism of epigenetic regulation.With the evolution of both experimental technologies and computational methods,major progress has been made in identifying the genomic locations and distributions of various RM types throughout the transcriptome.^(1)

Multifunctional dextran micelles as drug delivery carriers and magnetic resonance imaging probes

Multifunctional nanoparticles combining diagnostic and therapeutic agents into a single platform make cancer theranostics possible and have attracted wide interests in the field. In this study, a multifunctional nanocomposite based on dextran and superparamagnetic iron oxide nanoparticles （SPIO） was prepared for drug delivery and magnetic resonance imaging （MRI）. Amphiphilic dextran was synthesized by grafting stearyl acid onto the carbohydrate backbone, and micelle was formed by the resulted amphiphilic dextran with low critical micelle concentration at 1.8 mg L^-1. Doxorubicin （DOX） and a cluster of the manganese-doped iron oxide nanoparticles （Mn-SPIO） nanocrystals were then coencapsulated successfully inside the core of dextran micelles, resulting in nanocomposites with diameter at about 100 nm. Cell culture experiments demonstrated the potential of these Mn-SPIO/DOX nanocomposites as an effective multifunctional nanoplat- lk）rm for the delivery of anticancer drug DOX with a loading content （DLC） of 16 %. Confocal laser scanning microscopy reveals that the Mn-SPIO/DOX had excellent internalization ability against MCF-7/Adr cells after 2-h labeling compared with flee DOX.HCI. Under a 3.0-T MRI scanner, Mn-SPIO/ DOX nanocomposite-labeled cells in gelatin phantom show much darker images than the control. Their transverse relaxation （T2） rate is also significantly higher than that of the control cells （33.9 versus 2.3 s^-1）. Our result offers an effective strategy to treat MCF-7/Adr at optimized low dosages with imaging capability.