管理研究中的内生性

从统计推断到因果推断的关键在于有效解决内生性问题。受限于数据可获得性,管理学领域的大量研究问题仍需以非实验数据开展,因而内生性问题尤为明显。本文在梳理内生性起源及定义的基础上,直观展示了实证研究中出现内生性问题的原因,同时结合管理学经典研究案例探讨了内生性的不同来源及对应的处理策略,最后进一步探讨了近年来应用广泛的动态面板模型和空间计量模型处理内生性问题的思路,并就后续管理研究中的内生性问题处理提出了相关研究展望和可行性建议。

Carbides/nitrides precipitates in a C-Mn strip by CSP technology

The carbides/nitrides precipitates in ferrite grains, on grain boundaries and dislocations were investigated on a hot-rolled C-Mn strip （0.16wt%C-1.22wt%Mn-0.022wt%Ti） produced by the CSP （compact strip production） technology using TEM and X-ray energy dispersive spectroscopy. The Pickering＇s equation for the contribution of precipitates to the yield stress was also discussed. It is shown that there are numerous fine and dispersive precipitates TiC in the ferrite grains, on the grain boundaries and dislocations. Also there are a small amount of coarser Ti（C, N） particles and TiC particles associated with MnS. Precipitation strengthening on steels produced by the CSP technology is significant.

Discrete composition control of two-dimensional morphologic all-inorganic metal halide perovskite nanocrystals

Metal halide perovskite nanocrystals(NCs)exhibit impressive optical and electronic properties,making them an important class of functional materials with promising applications in solar cells,light emitting diodes(LEDs),photodetectors,and photocatalysts.In addition to the widely studied 0-dimensional(0 D)metal halide perovskite NCs,such as nanocubes,low dimensional perovskites,such as 2 D all-inorganic perovskite(AIP)NCs,subsist with directionally relevant quantum confinement.These anisotropic NCs have the propensity to exhibit interesting optoelectronic properties that are exceedingly difficult to introduce into 0 D systems,yet as of late are largely unexplored.In this review,we discuss the recent synthetic progress of 2 D all-inorganic metal halide perovskite NCs with ABX3 structure.Specifically,we highlight the discrete composition control of the cations(A and B sites)and anions(X site)by dopant incorporation and alloying in 2 D metal halide perovskite NCs.We will also discuss more complex perovskite crystal structures,such as Ruddlesden-Popper double perovskites,and compare these materials to 0 D perovskite systems.Ultimately,our work culminates in the future interests and perspectives of this field with a focus on the wide applicability of 2 D systems and the large variance in structure capable with discrete compositional tuning.

CMLP: Exploiting Caches at Multiple Levels of Proxies to Enhance Seamless Mobility Support in Information-Centric Networks

The recent evolution of the Internet towards "Information-centric" transfer modes has renewed the interest in exploiting proxies to enhance seamless mobility. In this work, we focus on the case of multiple levels of proxies in ICN architectures, in which content requests from mobile subscribers and the corresponding items are proactively cached to these proxies at different levels. Specifically, we present a multiple-level proactive caching model that selects the appropriate subset of proxies at different levels and supports distributed online decision procedures in terms of the tradeoff between delay and cache cost. We show via extensive simulations the reduction of up to 31.63% in the total cost relative to Full Caching, in which caching in all 1-level neighbor proxies is performed, and up to 84.21% relative to No Caching, in which no caching is used. Moreover, the proposed model outperforms other approaches with a flat cache structure in terms of the total cost.

Simulation research on dynamic performance of the new type high-pressure solenoid valve

To improve energy density,the transportation,storage,and operations of hydrogen,methane,and compressed air vehicles currently require high-pressure compression.High-pressure solenoid valve becomes the vital element to above system.In order to reduce leakage and aerodynamic force influence,a new type high-pressure solenoid valve was proposed.The simulation model which included electromagnetic model,aerodynamic force model was established by means of the nonlinear mathematic models.Using the software MATLAB/Simulink for simulation,the dynamic response characteristics of high-pressure pneumatic solenoid valve were obtained under different pulse width modulation(PWM)input control signals.Results show that,first of all,the new type of high-pressure solenoid valve can meet the switch requirement.Secondly,the opening movement and closing movement of the spool lags the PWM rising signal,and the coil current fluctuates significantly during the movement of the spool.Lastly,on/off status of high-pressure valve cannot be represented by the duty cycle.This research can be referred in the design of the high-pressure solenoid valve..

Viologen-based host–guest supramolecule with tunable intramolecular/intermolecular electron transfer chromism and dynamic fluorescence

Viologen,as a type of strong electron acceptor,is prone to undergo electron transfer(ET)and change color under external stimuli.However,due to the easy aggrega-tion of viologen molecules,they usually suffer from poorfluorescence emission in the condensed phase.Herein,a new viologen derivative of VioCl_(2)⋅2Cl(1^(2+)⋅2Cl)was designed and synthesized,in which thefluorescence was enhanced by intro-ducing Me-β-CD to weaken the interactions between viologen molecules.Then a viologen-based host-guest supramolecule of 1^(2+)@Me-β-CD was obtained by elec-trostatic interactions.Photo-/chemo-responded guest 1^(2+)supplies 1^(2+)@Me-β-CD,a green and dark purple caused by intramolecular and intermolecular ET.Further-more,1^(2+)@Me-β-CD displays an additional thermal responsive purple color.The triple chromic behaviors all exhibit excellent reversibility and cycling stability.As expected,1^(2+)@Me-β-CD exhibits strong photoluminescence(PL)in solid-liquid dual states,presenting an improved quantum yield(Φ)from 1^(2+)(Φ_(s)=0.37%,Φ_(1)= 16.74%)to=1^(2+)@Me-β-CD(Φ_(s)= 10.45%,Φ_(1)= 25.86%),and thefluores-=cence intensity can be dynamically modulated by light,heat,and acid/base vapors.The multi-responsive chromism and tunablefluorescence of 1^(2+)@Me-β-CD allow for potential applications in information security and smart windows.

A chromosome-level genome assembly of the miiuy croaker(Miichthys miiuy)using nanopore sequencing and Hi-C

Miiuy croaker,Miichthys miiuy is an ecologically important teleost species which is widely distributed in southeast coast of China.In this study,we present a chromosomal-scale genome assembly of the miiuy croaker which is an important Sciaenidae fish and economical species.We adopted Oxford Nanopore and Hi-C sequencing techniques to achieve an assembly with high accuracy and completeness.The investigation of genome characteristic and functional features may provide insights into the study of phylogenetic diversity of miiuy croaker.This study can also be beneficial to improve molecular assisted breeding techniques.Moreover,it can be a great resource to better conduct further study of other sciaenids.

Multidimensional CdS nanowire/CdIn2S4 nanosheet heterostructure for photocatalytic and photoelectrochemical applications

Nanomaterial shapes can have profound effects on material properties, and therefore offer an efficient way to improve the performances of designed materials and devices. The rational fabrication of multidimensional architectures such as one dimensional （1D）-two dimensional （2D） hybrid nanomaterials can integrate the merits of individual components and provide enhanced functionality. However, it is still very challenging to fabricate 1D/2D architectures because of the different growth mechanisms of the nanostructures. Here, we present a new solvent- mediated, surface reaction-driven growth route for synthesis of CdS nanowire （NW）/CdIn2S4 nanosheet （NS） 1D/2D architectures. The as-obtained CdS NW/ CdIn2S4 NS structures exhibit much higher visible-light-responsive photocatalytic activities for water splitting than the individual components. The CdS NW/CdIn2S4 NS heterostructure was further fabricated into photoelectrodes, which achieved a considerable photocurrent density of 2.85 mA·cm^-2 at 0 V vs. the reversible hydrogen electrode （RHE） without use of any co-catalysts. This represents one of the best results from a CdS-based photoelectrochemical （PEC） cell. Both the multidimensional nature and type II band alignment of the 1D/2D CdS/CdIn2S4 heterostructure contribute to the enhanced photocatalyfic and photoelectrochemical activity. The present work not only provides a new strategy for designing multidimensional 1D/2D heterostructures, but also documents the development of highly efficient energy conversion catalysts.

Enhanced singlet oxygen generation by hybrid Mn-doped nanocomposites for selective photo-oxidation of benzylic alcohols

Transition-metal ions doped nanocrystals(NCs),specifically Mn-doped NCs,hold great potential in the field of photocatalysis,especially,to improve photocatalytic performance for singlet oxygen(1O2)generation.Here,we report the design of a novel Mn-doped NC-based nanocomposites,specifically,silica-coated Mn-doped CdS/ZnS NCs decorated with Pt NCs(denoted as Mn-NCs@SiO2-Pt),which enhance photocatalytic 1O2 generation.Owing to the long-lived Mn excited state(on the order of ms),the energy-transfer between Mn-NCs and molecular oxygen is facilitated with the assistance of the Pt NCs adhered to the Mn-NC@SiO2 surface.Therefore,the Mn-NCs@SiO2-Pt composites,integrate the advantages of Mn-doped NCs,a protective silica layer,and Pt NCs to exhibit excellent catalytic activity and selectivity for the selective oxidation of primary benzylic alcohols to aldehydes through an 1O2 engaged oxidation process under visible-light irradiation.This work paves the way for enhancing catalytic performance via facilitated energy transfer relaxation by utilizing the long-lived excited-state of Mn2+dopant ions in nanocomposites.

Long noncoding RNA AANCR modulates innate antiviral responses by blocking miR-210-dependent MITA downregulation in teleost fish,Miichthys miiuy

Viral infection induces the initiation of antiviral effectors and cytokines which are critical mediators of innate antiviral responses.The critical molecular determinants are responsible for triggering an appropriate immune response.Long noncoding RNAs(lncRNAs)have emerged as new gene modulators involved in various biological processes,while how lncRNAs operate in lower vertebrates are still unknown.Here,we discover a long noncoding RNA,termed antiviral-associated long noncoding RNA(AANCR),as a novel regulator for innate antiviral responses in teleost fish.The results indicate that fish MITA plays an essential role in host antiviral responses and inhibition of Siniperca chuatsi rhabdovirus(SCRV)production.miR-210 reduces MITA expression and suppress MITA-mediated antiviral responses,which may help viruses evade host antiviral responses.Further,AANCR functions as a competing endogenous RNA(ceRNA)for miR-210 to control protein abundance of MITA,thereby inhibiting SCRV replication and promoting antiviral responses.Our data not only shed new light on understanding the function role of lncRNA in biological processes in teleost fish,but confirmed the hypothesis that ceRNA networks exist widely in vertebrates.

Thermal cycling creep properties of a directionally solidified superalloy DZ125

Aero-engine turbine blades may suffer overheating during service,which can result in severe microstructural and mechanical degradation within tens of seconds.In this study,the thermal cycling creep under(950℃/15 min+1100℃/1 min)-100 MPa was performed on a directionally solidified superalloy,DZ125.The effects of overheating and thermal cycling on the creep properties were evaluated in terms of creep behavior and microstructural evolution against isothermally crept specimens under 950℃/100 MPa,950℃/270 MPa,and 1100℃/100 MPa.The results indicated that the thermal cycling creep life was reduced dramatically compared to the isothermal creep under 950℃/100 MPa.The plastic creep deformation mainly occurred during the overheating stage during the thermal cycling creep.The thermal cycling creep curve exhibited three stages,similar to the 1100℃isothermal creep,but its minimum creep rate occurred at a lower creep strain.The overheating events caused severe microstructural degradation,such as substantial dissolution ofγ'phase,earlier formation of raftedγ'microstructure,widening of theγchannels,and instability of the interfacial dislocation networks.This microstructural degradation was the main reason for the dramatic decrease in thermal cycling creep life,as the thermal cycling promoted more dislocations to cut intoγ'phase and more cracks to initiate at grain boundaries,carbides,and residual eutectic pools.This study underlines the importance of evaluating the thermal cycling creep properties of superalloys to be used as turbine blades and provides insights into the effect of thermal cycling on directionally solidified superalloys for component design.

MicroRNA negatively regulates NF-κB-mediated immune responses by targeting NOD1 in the teleost fish Miichthys miiuy

Inflammation is a self-protection mechanism that can be triggered when innate immune cells detect infection.Eradication of pathogen infection requires appropriate immune and inflammatory responses,but excessive inflammatory responses can cause uncontrolled inflammation,autoimmune diseases,or pathogen dissemination.Mounting evidence has shown that microRNAs(miRNAs)in mammals act as important and versatile regulators of innate immunity and inflammation.However,miRNAmediated regulation networks are largely unknown in inflammatory responses in lower vertebrates.Here,miR-144 and miR-217 are identified as negative regulators in teleost inflammatory responses.We find that Vibrio harveyi and lipopolysaccharide(LPS)treatment significantly upregulate the expression of fish miR-144 and miR-217.Upregulated miR-144 and miR-217 suppress LPS-induced inflammatory cytokine expression by targeting nucleotide-binding oligomerization domain-containing protein 1(NOD1),thereby avoiding excessive inflammatory responses.In addition,miR-144 and miR-217 regulate inflammatory responses through NOD1-induced nuclear factor kappa(NF-κB)signaling pathways.These findings demonstrate that miR-144 and miR-217 play regulatory roles in inflammatory responses by modulating the NOD1-induced NF-κB signaling pathway.

Long noncoding RNA TARL promotes antibacterial activity and prevents bacterial escape in Miichthys miiuy through suppression of TAK1 downregulation

Noncoding RNA(ncRNA)is an important regulatory factor that plays a major role in innate immunity.However,most studies on ncRNA have focused on mammals,resulting in a knowledge gap on nc RNA in lower vertebrates such as teleost fish.In this study,we identified a new long noncoding RNA(lncRNA),termed TAK1-related lnc RNA(TARL),which can play a positive role in the antibacterial immunity of Miichthys miiuy to Vibrio anguillarum and V.harveyi.We also found a novel micro RNA miR-2188-3p that could target TAK1 and inhibit the host antibacterial response and promote bacterial escape.We further found that the antibacterial effect inhibited by miR-2188-3p could be reversed with TARL.Moreover,V.anguillarum and V.harveyi are the two most susceptible Gram-negative pathogens of aquaculture fish,and the economic losses caused by these two bacteria are immeasurable every year.This study is the first to report on the ability of lnc RNA to prevent the escape of V.anguillarum and V.harveyi in fish through the competing endogenous RNA(ceRNA)mechanism.Our results not only elucidate the ce RNA mechanism of the lncRNA in antibacterial immune responses but also provide new insights into the impact of lnc RNA on host immunity and bacterial escape.

Effects of iodoacetic acid drinking water disinfection byproduct on the gut microbiota and its metabolism in rats

Iodoacetic acid(IAA) is an unregulated disinfection byproduct in drinking water and has been shown to exert cytotoxicity, genotoxicity, tumorigenicity, and reproductive and developmental toxicity. However, the effects of IAA on gut microbiota and its metabolism are still unknown, especially the association between gut microbiota and the metabolism and toxicity of IAA. In this study, female and male Sprague–Dawley rats were exposed to IAA at 0 and 16 mg/kg bw/day daily for 8 weeks by oral gavage. Results of 16S r RNA gene sequencing showed that IAA could alter the diversity, relative abundance and function of gut microbiota in female and male rats. IAA also increased the abundance of genes related to steroid hormone biosynthesis in the gut microbiota of male rats. Moreover, metabolomics profiling revealed that IAA could significantly disturb 6 and 13 metabolites in the feces of female and male rats, respectively. In female rats, the level of androstanediol increased in the IAA treatment group. These results were consistent with our previous findings, where IAA was identified as an androgen disruptor. Additionally, the perturbed gut microbiota and altered metabolites were correlated with each other. The results of this study indicated that IAA could disturb gut microbiota and its metabolism. These changes in gut microbiota and its metabolism were associated with the reproductive and developmental toxicity of IAA.

Gd-doped CuBi_(2)O_(4)/CuO heterojunction film photocathodes for photoelectrochemical H_(2)O_(2)production through oxygen reduction

Photoelectrochemical oxygen reduction reaction(ORR)toward H_(2)O_(2)is highly desirable because only sunlight,O_(2)and water are required in the process.However,the corresponding studies are still at its infancy because of the lack of suitable photocathodes,especially inorganic semiconductor photocathodes.In this work,we report CuBi_(2)O_(4)/CuO(CBO/CuO)heterojunction submicrocrystalline film photocathodes with efficient ORR activity for H_(2)O_(2)production.The heterojunction film photocathodes were prepared through thermal evaporation of Cu and Bi metals under vacuum and subsequent annealing treatment.Furthermore,the doping of Gd^(3+)ions into CBO/CuO could significantly enhance the yield of H_(2)O_(2).As a result,the concentration of H_(2)O_(2)could reach 1.3 mM within 30 min,which is 6 times higher than that obtained on the pristine CBO/CuO photocathode.The theoretical calculations suggested that the introduction of Gd could adjust the electronic structure of CBO surface and promote 2e ORR pathway for selective production of H_(2)O_(2).Our work not only provides a new strategy for designing highly efficient photocathode for H_(2)O_(2)production but also will evoke more interest in photoelectrocatalytic ORR through inorganic semiconductor photocathode.

多维度溢出效应政策评估方法、思路与中国优势——基于空间网络建模视角

在梳理固定效应模型、工具变量法、双重差分法、断点回归设计、合成控制法等传统政策效应评估方法基础上,本文介绍了多维度溢出效应下的政策评估方法,并强调了空间网络计量模型应对多维溢出效应挑战的独特优势。特别地,本文重点探讨了空间网络计量模型在处理单一政策存在个体或区域间溢出、政策效应和溢出效应均存在动态变化、组合政策存在多维度效果溢出、政策效应存在于高维空间网络数据等四类情形时的政策评估方法、识别与估计问题。中国交通、互联网等硬件基础设施建设的不断完善,以及全国统一大市场等软环境的日益改善,成为提供中国学者深入探讨政策效应评估方法的原创沃土和独特优势。在政策效果溢出效应复杂化的当下,本文的探讨可为政策评估方法未来的发展提供重要参考。

Total organic halogen(TOX) in human urine: A halogen-specific method for human exposure studies

Disinfection by-products（DBPs） are a complex mixture of compounds unintentionally formed as a result of disinfection processes used to treat drinking water. Effects of long-term exposure to DBPs are mostly unknown and were the subject of recent epidemiological studies. However,most bioanalytical methods focus on a select few DBPs. In this study, a new comprehensive bioanalytical method has been developed that can quantify mixtures of organic halogenated compounds, including DBPs, in human urine as total organic chlorine（TOCl）, total organic bromine（TOBr）, and total organic iodine（TOI）. The optimized method consists of urine dilution, adsorption to activated carbon, pyrolysis of activated carbon, absorption of gases in an aqueous solution, and halide analysis with ion chromatography and inductively coupled plasma-mass spectrometry. Spike recoveries for TOCl, TOBr, and TOI measurements ranged between 78% and 99%. Average TOCl, TOBr, and TOI concentrations in five urine samples from volunteers who consumed tap water were 1850, 82, and 21.0 μg/L as X^-, respectively.Volunteers who consumed spring water（control） had TOCl, TOBr, and TOI average concentrations in urine of 1090, 88, and 10.3 μg/L as X^-, respectively. TOCl and TOI in the urine samples from tap water consumers were higher than the control. However, TOBr was slightly lower in tap water urine samples compared to mineral water urine samples, indicating other sources of environmental exposure other than drinking water. A larger sample population that consumes tap water from different cities and mineral water is needed to determine TOCl, TOBr, and TOI exposure from drinking water.

A chromosome-level genome assembly of the blackspotted croaker(Protonibea diacanthus)

The blackspotted croaker(Protonibea diacanthus)is an endangered coastal marine fish.It is also a valuable species that is cultured on the southeast coast of China.While some genetic studies have been conducted to protect this species,genomic resources are lacking.Here,we report a chromosome-scale assembly of P.diacanthus genome by high-depth genome sequencing,assembly,and annotation.The genome scale was 635.69 Mb with contig and scaffold N50 length of 3.33 Mb and 25.60 Mb,respectively.Hi-C scaffolding of the genome resulted in 24 chromosomes of 94.15%total genome.We predicted 23,971 protein-coding genes.In addition,we constructed a phylogenetic tree using 2755 single-copy gene families and identified 462 unique gene families in P.diacanthus genome compared to three other sciaenids.What’s more,from the analysis of gene families,we found that several gene families related to innate immunity were significantly expanded in the blackspotted croaker genome compared to other teleost genomes.The high-quality genome can improve our understanding of the molecular mechanisms behind economically valuable traits and provide insights into characteristics of the immune system.

A chromosome-level genome assembly of the red drum, Sciaenops ocellatus

Sciaenops ocellatus,also known as red drum,is a valuable commercial fish that is widely cultured in China.In recent years,while the genetic research and molecular breeding on S.ocellatus has been widely performed,whole-genome resources are lacking.In our study,we assembled the S.ocellatus genome by high-quality genome sequencing,followed by complete annotation.The size of final genome was 686.62 Mb and N50 length of contig and scaffold is 99.71 Kb and 25.62 Mb,respectively.Using the Hi-C technology,we obtained 24 pseudochromosomes containing 87.82%of the total scaffolds.We annotated 20,053 protein-coding genes in S.ocellatus genome,of which 99.93%were homologous to proteins in different database.Totally,we detected 133.54 Mb repeat sequences,which accounts for 19.45%of the assembly.According to the phylogenetic analysis,S.ocellatus is most closed to L.croea with a divergence time about 30 million years ago.We assembled a high-quality genome that will be a valuable resource to further study the biology of S.ocellatus and will inform how to breed the red drum to enhance its economic traits.

A biomimetic liver cancer on-a-chip reveals a critical role of LIPOCALIN-2 in promoting hepatocellular carcinoma progression

Hepatic stellate cells(HSCs)represent a significant component of hepatocellular carcinoma(HCC)microenvironments which play a critical role in tumor progression and drug resistance.Tumor-ona-chip technology has provided a powerful in vitro platform to investigate the crosstalk between activated HSCs and HCC cells by mimicking physiological architecture with precise spatiotemporal control.Here we developed a tri-cell culture microfluidic chip to evaluate the impact of HSCs on HCC progression.Onchip analysis revealed activated HSCs contributed to endothelial invasion,HCC drug resistance and natural killer(NK)cell exhaustion.Cytokine array and RNA sequencing analysis were combined to indicate the iron-binding protein LIPOCALIN-2(LCN-2)as a key factor in remodeling tumor microenvironments in the HCC-on-a-chip.LCN-2 targeted therapy demonstrated robust anti-tumor effects both in vitro 3D biomimetic chip and in vivo mouse model,including angiogenesis inhibition,sorafenib sensitivity promotion and NK-cell cytotoxicity enhancement.Taken together,the microfluidic platform exhibited obvious advantages in mimicking functional characteristics of tumor microenvironments and developing targeted therapies.