Betulinic acid protects against ovarian impairment by decreasing F-2 toxin-induced oxidative stress and inflammation associated with the downregulation of p38 expression in mice

F-2 toxin is an estrogenic mycotoxin that causes reproductive disorders in animals.Betulinic acid(BA)is a natural pentacyclic lupane-structure triterpenoid that has diverse pharmacological activities.In this study,the antioxidative and anti-inflammatory effects of BA and its underlying mechanism are explored in F-2 toxin-triggered mouse ovarian damage.We found that BA alleviated the F-2 toxin-induced ovarian impairment by stimulating follicle growth,reducing inflammatory cell infiltration,repairing damaged mitochondria and endoplasmic reticulum.Simultaneously,BA not only reversed F-2 toxin-induced reduction of follicle stimulating hormone(FSH)and luteinizing hormone(LH)levels in the serum,but also restrained the protein expression of the estrogen receptors a(ERa)and ERβ.Moreover,BA restored the balance of F-2 toxin-induced ovarian redox system disorders.Subsequently,we found that 0.25 mg/kg BA played an anti-inflammatory role in the F-2 toxin-induced ovarian impairment by decreasing interleukin-1β(IL-1β).IL-6,and tumor necrosis factor-α(TNF-α)mRNA expression,as well as inhibiting p38 protein expression.These data demonstrated that BA exerts its protective effect on F-2 toxin-induced ovarian oxidative impairment and inflammation by inhibiting p38 expression,which implies a natural product-based medicine to ameliorate F-2 toxin-caused female reproductive toxicity and provides a detoxifying method for food contaminated by mycotoxin.

A color image encryption algorithm based on hyperchaotic map and DNA mutation

We devise a color image encryption scheme via combining hyperchaotic map,cross-plane operation and gene theory.First,the hyperchaotic map used in the encryption scheme is analyzed and studied.On the basis of the dynamics of hyperchaotic map,a color image encryption scheme is designed.At the end of the encryption process,a DNA mutation operation is used to increase the encoding images’randomness and to improve the encryption algorithm’s security.Finally,simulation experiments,performance analysis,and attack tests are performed to prove the effectiveness and security of the designed algorithm.This work provides the possibility of applying chaos theory and gene theory in image encryption.

Geometric Mean Decomposition Based Hybrid Precoding for Millimeter-Wave Massive MIMO

Hybrid precoding can reduce the number of required radio frequency(RF)chains in millimeter-Wave(mmWave) massive MIMO systems. However, existing hybrid precoding based on singular value decomposition(SVD) requires the complicated bit allocation to match the different signal-to-noise-ratios(SNRs) of different sub-channels. In this paper,we propose a geometric mean decomposition(GMD)-based hybrid precoding to avoid the complicated bit allocation. Specifically,we seek a pair of analog and digital precoders sufficiently close to the unconstrained fully digital GMD precoder. To achieve this, we fix the analog precoder to design the digital precoder, and vice versa. The analog precoder is designed based on the orthogonal matching pursuit(OMP) algorithm, while GMD is used to obtain the digital precoder. Simulations show that the proposed GMD-based hybrid precoding achieves better performance than the conventional SVD-based hybrid precoding with only a slight increase in complexity.

Passive Beamforming Design for Intelligent Reflecting Surface Assisted MIMO Systems

Intelligent reflecting surfaces(IRSs)constitute passive devices,which are capable of adjusting the phase shifts of their reflected signals,and hence they are suitable for passive beamforming.In this paper,we conceive their design with the active beamforming action of multiple-input multipleoutput(MIMO)systems used at the access points(APs)for improving the beamforming gain,where both the APs and users are equipped with multiple antennas.Firstly,we decouple the optimization problem and design the active beamforming for a given IRS configuration.Then we transform the optimization problem of the IRS-based passive beamforming design into a tractable non-convex quadratically constrained quadratic program(QCQP).For solving the transformed problem,we give an approximate solution based on the technique of widely used semidefinite relaxation(SDR).We also propose a low-complexity iterative solution.We further prove that it can converge to a locally optimal value.Finally,considering the practical scenario of discrete phase shifts at the IRS,we give the quantization design for IRS elements on basis of the two solutions.Our simulation results demonstrate the superiority of the proposed solutions over the relevant benchmarks.

Experimental Study on the Influence Mechanism of Carbon Fiber/Epoxy Composite Reinforcement and Matrix on Its Fire Performance

The effects of the number of layers,the arrangement of carbon fiber(CF)tow and the epoxy resin(ER)matrix on the fire performance of carbon fiber/epoxy composites(CFEC)were studied by a variety of experimental methods.The results show that the number of layers of CF tow has influence on the combustion characteristics and fire propagation of the composites.The arrangement of CF tow has influence on flame propagation rate and high temperature mechanicalproperties.The mechanism of the influence of the number of layers of CF tow on the composite is mainly due to the different thermal capacity of ER matrix.The effect of the arrangement of CF tow on the fire performance of the composite is mainly due to the inhibition and obstruction of the tow on the combustion of ER matrix.The influence on the high temperature mechanicalproperties is mainly due to the different arrangement direction of CF tow.The fitting equation of the mechanicalproperties of the samples was obtained.This equation could be used to predict the samples’tensile strength from 25°C to 150℃by comparing with the experimental results.Taking the carbon fiber woven cloth(C)applied in the fuselage material as an example,combining the influencing factors of various parameters in the fire field,some suggestions are put forward combined with the research conclusion.

Unveiling the effect of amino acids on the crystallization pathways of methylammonium lead iodide perovskites

Multifunctional additives are widely used to improve crystallization and to passivate defects in perovskite solar cells. The roles of these additives are usually related to the various functional groups contained in such additives. Here, we introduce a serious of analogues of amino acids into methylammonium lead iodide perovskites and find they play different roles in the crystallization process despite the fact that these additives share exactly the same terminal groups, namely one amino group and one carboxyl group. The corresponding crystallization pathways are established for the first time via monitoring the time-resolved phase formation and transformation. We find that avoiding the rapid formation of perovskites from precursor solution can facilitate the uniform nucleation and growth of perovskite crystals with enhanced crystallinity and reduced defects. Further, we find the different crystallization behaviors probably arise from the inherent structural characteristic of these additives, leading to different interactions in the precursors. This study unveils the effects of amino acids on the liquid–solid crystallization process and helps better understand the role of multifunctional additives beyond their functional groups.

Optical spectroscopy study of damage evolution in 6H-SiC by H_(2)^(+)implantation

Lattice defects induced by ion implantation into SiC have been widely investigated in the decades by various techniques.One of the non-destructive techniques suitable to study the lattice defects in SiC is the optical characterization.In this work,confocal Raman scattering spectroscopy and photoluminescence spectrum have been used to study the effects of 134-keV H_(2)^(+)implantation and thermal treatment in the microstructure of 6H-SiC single crystal.The radiation-induced changes in the microstructure were assessed by integrating Raman-scattering peaks intensity and considering the asymmetry of Raman-scattering peaks.The integrated intensities of Raman scattering spectroscopy and photoluminescence spectrum decrease with increasing the fluence.The recovery of the optical intensities depends on the combination of the implantation temperature and the annealing temperature with the thermal treatment from 700℃to 1100℃.The different characterizations of Raman scattering spectroscopy and photoluminescence spectrum are compared and discussed in this study.

Three-dimensional porous In_(2)O_(3) arrays for self-powered transparent solar-blind photodetectors with high responsivity and excellent spectral selectivity

Transparent solar-blind ultraviolet photodetectors(SBUV PDs)have extensive applications in versatile scenarios,such as optical communication.However,it is still challenging to simultaneously achieve high responsivity,high transparency,and satisfying self-powered capability.Here,we demonstrated high-performance,transparent,and self-powered photoelectrochemical-type(PEC)SBUV PDs based on vertically grown ultrathin In_(2)O_(3) nanosheet arrays(NAs)with a three-dimensional(3D)porous structure.The 3D porous structure simultaneously improves the transmittance in the visible light region,accelerates interfacial reaction kinetics,and promotes photogenerated carrier transport.The performance of In_(2)O_(3) NAs photoanodes exceeds most reported self-powered PEC SBUV PDs,exhibiting a high transmittance of approximately 80%in the visible light region,a high responsivity of 86.15 mA/W for 254 nm light irradiation,a fast response speed of 15/18 ms,and good multicycle stability.The In_(2)O_(3) NAs also show excellent spectral selectivity with an ultrahigh solar-blind rejection ratio of 1319.30,attributed to the quantum confinement effect induced by the ultrathin feature(2-3 nm).Furthermore,In_(2)O_(3) NAs photoanodes show good capability in underwater optical communication.Our work demonstrated that a 3D porous structure is a powerful strategy to synchronously achieve high responsivity and transparency and provides a new perspective for designing high-performance,transparent,and self-powered PEC SBUV PDs.

Recent progress in engineering Clostridium autoethanogenum to synthesize the biochemicals and biocommodities

Excessive mining and utilization fossil fuels has led to drastic environmental consequences,which will contribute to global warming and cause further climate change with severe consequences for the human population.The magnitude of these challenges requires several approaches to develop sustainable alternatives for chemicals and fuels production.In this context,biological processes,mainly microbial fermentation,have gained particular interest.For example,autotrophic gas-fermenting acetogenic bacteria are capable of converting CO,CO_(2) and H_(2) into biomass and multiple metabolites through Wood-Ljungdahl pathway,which can be exploited for large-scale fermentation processes to sustainably produce bulk biochemicals and biofuels(e.g.acetate and ethanol)from syngas.Clostridium autoethanogenum is one representative of these chemoautotrophic bacteria and considered as the model for the gas fermentation.Recently,the development of synthetic biology toolbox for this strain has enabled us to study and genetically improve their metabolic capability in gas fermentation.In this review,we will summarize the recent progress involved in the understanding of physiological mechanism and strain engineering for C.autoethanogenum,and provide our perspectives on the future development about the basic biology and engineering biology of this strain.

Role of the cathode chamber in microbial electrosynthesis:A comprehensive review of key factors

The consumption of non-renewable fossil fuels has directly contributed to a dramatic rise in global carbon dioxide(CO_(2))emissions,posing an ongoing threat to the ecological security of the Earth.Microbial electrosynthesis(MES)is an innovative energy regeneration strategy that offers a gentle and efficient approach to converting CO_(2) into high-value products.The cathode chamber is a vital component of an MES system and its internal factors play crucial roles in improving the performance of the MES system.Therefore,this review aimed to provide a detailed analysis of the key factors related to the cathode chamber in the MES system.The topics covered include inward extracellular electron transfer pathways,cathode materials,applied cathode potentials,catholyte pH,and reactor configuration.In addition,this review analyzes and discusses the challenges and promising avenues for improving the conversion of CO_(2) into high-value products via MES.

Randomized whispering-gallery-mode microdisk laser arrays via cavity deformations for anti-counterfeiting labels

Optical physical unclonable functions(PUFs)have emerged as a promising strategy for effective and unbreakable anti-counterfeiting.However,the unpredictable spatial distribution and broadband spectra of most optical PUFs complicate efficient and accurate verification in practical anti-counterfeiting applications.Here,we propose an optical PUF-based anti-counterfeiting label from perovskite microlaser arrays,where randomness is introduced through vapor-induced microcavity deformation.The initial perovskite microdisk laser arrays with regular positions and uniform sizes are fabricated by femtosecond laser direct ablation.By introducing vapor fumigation to induce random deformations in each microlaser cavity,a laser array with completely uneven excitation thresholds and narrow-linewidth lasing signals is obtained.As a proof of concept,we demonstrated that the post-treated laser array can provide fixed-point and random lasing signals to facilitate information encoding.Furthermore,different emission states of the lasing signal can be achieved by altering the pump energy density to reflect higher capacity information.A threefold PUF(excited under three pump power densities)with a resolution of 5×5 pixels exhibits a high encoding capacity(1.43×10^(45)),making it a promising candidate to achieve efficient authentication and high security with anti-counterfeiting labels.

Efficient blue light-responsed dithienylethenes with exceptional photochromic performance

Three novel dithienylethenes modified by bifluoroboron β-diketonate fragments have been successfully developed. Upon blue light irradiation, they reached photostationary state within 2-5 s, as well as 100% conversion ratio and photocyclization quantum yield of > 0.70. Such fascinating photochromism were endowed by collaborative role of electron-withdrawing effect of BF_(2)bdk group to reduce HOMO-LUMO electronic gap for the open isomer, together with intramolecular hydrogen bonds and CH-π interactions favoring antiparallel conformation fixation. Moreover, they displayed specific discrimination and photoswitchable bacterial imaging for S. aureus.

基于动态因果模型的男性长期吸烟者默认网络有效连接分析

目的探讨男性长期吸烟者默认网络有效连接的异常改变,及其与吸烟临床特征的相关性。方法回顾性分析2014年1月至2018年12月通过微信等网络平台招募的131名受试者的静息态功能磁共振成像数据,其中长期吸烟者76名[长期吸烟组,男性,年龄20~55(32.1±6.3)岁],对照者55名[对照组,男性,年龄22~55(32.3±7.4)岁]。长期吸烟者定义为每天吸烟不少于10支,烟龄2年以上且符合美国精神障碍诊断统计手册第4版(DSM-Ⅳ)关于物质依赖诊断标准的人群。选取默认网络中4个主要节点为感兴趣区,分别为左侧顶下小叶(LIPL),右侧顶下小叶(RIPL),后扣带回皮质(PCC),内侧前额叶皮质(mPFC)。基于动态因果模型分析吸烟组及对照组默认网络有效连接(EC)的改变。并分析有差异的EC与尼古丁依赖量表评分(FTND)、吸烟指数及烟龄的相关性。结果与对照组相比,吸烟组LIPL至PCC、PCC至mPFC的EC减弱(EC分别为-0.091、-0.174,均贝叶斯后验概率>0.95),RIPL至PCC的EC增强(EC为0.136,贝叶斯后验概率>0.95)。此外,从LIPL到PCC的EC与吸烟指数呈负相关(r=-0.282,P=0.017)。差异有统计学意义的EC与FTND评分及烟龄在组间比较时未发现存在相关性(r=-0.103、-0.089,均P>0.05)。结论长期吸烟者在IPL-PCC-mPFC神经回路中表现出异常的信息传递,并与吸烟指数相关。

Predictions of NOx/N2O emissions from an ultra-supercritical CFB boiler using a 2-D comprehensive CFD combustion model

NOx and N2O emissions from an ultra-supercritical circulating fluidized bed(CFB)boiler were predicted using a two dimensional(2-D)comprehensive computational fluid dynamics(CFD)combustion model.This model was developed from a three dimensional model for a supercritical CFB boiler previously constructed by our group.Based on an analysis of the NOx and N2O conversion processes in a CFB boiler,the primary formation and destruction reactions were introduced into the 2-D model and coupled.The resulting model was validated using data from the Baima 600 MW supercritical CFB boiler,and then applied to a 660 MW ultra-supercritical CFB boiler.The effects of excess air,the secondary air(SA)to(primary air(PA)plus SA)ratio and the SA injection height on NOx and N2O emissions were investigated.The results show that a higher excess air volume increases both NOx and N2O emissions,while increasing the SA/(PA+SA)ratio somewhat reduces both the NOx and N2O concentrations.On the basis of the results of this work,optimal locations for SA injection ports so as to lower NOx and N2O emissions are recommended.

Bifunctional 3D n-doped porous carbon materials derived from paper towel for oxygen reduction reaction and supercapacitor

Designing and fabricating cheap and active bifunctional materials is crucial for the development of renewable energy technologies.In this article,three-dimensional nitrogen-doped porous carbon materials(NDPC-X,in which X represents the pyrolysis temperature) were fabricated by simultaneous carbonization and activation of polypyrrole-coated paper towel protected by a silica layer followed by acid etching.The material had a high specific surface area(1,123.40 m^2/g).The as-obtained NDPC-900 displayed outstanding activity as a catalyst for the oxygen reduction reaction(ORR) as well as an electrode with a high specific capacitance in a supercapacitor in an alkaline medium.The NDPC-900 catalyst for the ORR exhibited a more positive reduction peak potential of à0.068 V(vs.Hg|HgCl^2) than that of Pt/C(-0.121 V),as well as better cycling stability and stronger methanol tolerance.Moreover,the NDPC-900 had a high specific capacitance of 379.50 F/g at a current density of 1 A/g,with a retention rate of 94.5% after 10,000 cycles in 6 mol/L KOH electrolyte when used as an electrode in a supercapacitor.All these results were attributed to the effect of a large surface area,which provided electrochemically active sites.This work introduces an effective way to use biomass-derived materials for the synthesis of promising bifunctional carbon material for electrochemical energy conversion and storage devices.

基于分子识别功能的铁卟啉/杯八芳烃/石墨烯三元复合材料的制备及其多巴胺电化学传感性能研究

本文用界面自组装法将具有电催化活性的四联苯基铁卟啉(Fe TBPP)和具有特异分子识别功能的对叔丁基杯[8]芳烃(C[8]A)通过自组装法与高导电性的氧化石墨烯(GO)相结合,得到三元Fe TBPP/C[8]A/GO复合膜.对复合膜的结构表征发现,GO的共轭平面和亲水基团分别与Fe TBPP和C[8]A分子有π-π和氢键相互作用,使得两种分子在GO模板上呈现良好的分散性;与这两种分子的单组分膜相比,复合膜具有更加均匀的颗粒形貌和更高的导电性.电化学测试表明,响应电流与多巴胺(DA)浓度呈线性关系,检测范围宽至0.1~1000μM,灵敏度高达17.6μA/mmol,检出限低至25.6 n M.更重要的是,GO对Fe TBPP和C[8]A的锚定和分散使得复合电极对DA的检测具有稳定性、重现性和高选择性,并且该传感器可实现应用于人体尿液和血清样品中DA的高灵敏检测.

SEM imaging of insulating specimen through a transparent conducting veil of carbon nanotube

Observing the morphology of insulating specimen in scanning electron microscope(SEM)is of great significance for the nanoscale semiconductor devices and biological tissues.However,the charging effect will cause image distortion and abnormal contrast when observing insulating specimen in SEM.A typical solution to this problem is using metal coating or water-removable conductive coating.Unfortunately,in both cases the surface of the specimen is covered by a thin layer of conductive material which hides the real surface morphology and is very difficult to be completely removed after imaging.Here we show a convenient,residue-free,and versatile method to observe real surface morphology of insulating specimen without charging effect in SEM with the help of a nanometer-thick film of super-aligned carbon nanotube(SACNT).This thin layer of SACNT film,like metal,can conduct the surface charge on insulating specimen through the sample stage to the ground,thus eliminating the charging effect.SACNT film can also be used as the conductive tape to carry and immobilize insulating powder or particles during SEM imaging.Different from the metal coating,SACNT film is transparent,so that the real microstructure of the insulating specimen surface can be observed.In addition,SACNT film can be easily attached to and peeled off from the surface of specimen without any residue.This convenient,residue-free,and versatile method can open up new possibilities in nondestructive SEM imaging of a wide variety of insulating materials,semiconductor devices,and biological tissues.