Preparation of single atom catalysts for high sensitive gas sensing

Single atom catalysts(SACs)have garnered significant attention in the field of catalysis over the past decade due to their exceptional atom utilization efficiency and distinct physical and chemical properties.For the semiconductor-based electrical gas sensor,the core is the catalysis process of target gas molecules on the sensitive materials.In this context,the SACs offer great potential for highly sensitive and selective gas sensing,however,only some of the bubbles come to the surface.To facilitate practical applications,we present a comprehensive review of the preparation strategies for SACs,with a focus on overcoming the challenges of aggregation and low loading.Extensive research efforts have been devoted to investigating the gas sensing mechanism,exploring sensitive materials,optimizing device structures,and refining signal post-processing techniques.Finally,the challenges and future perspectives on the SACs based gas sensing are presented.

Factors affecting meibomian gland area loss in symptomatic adults

AIM:To characterize the distribution of meibomian gland(MG)area loss(MGL)and its relationship with demographic characteristics,mites,and symptoms.METHODS:This retrospective observational study included patients who visited the Dry Eye Clinic of Shenzhen Eye Hospital between June 2020 and August 2021.General patient characteristics,ocular symptoms,Demodex test results of the eyelid edges,and the results of a comprehensive ocular surface analysis were collected.MGL was analyzed using Image J software.RESULTS:This study enrolled 1204 outpatients aged 20-80(40.70±13.44)y,including 357 males(29.65%)and 847 females(70.35%).The patients were classified into mild(n=155;12.87%),moderate(n=795;66.03%),severe(n=206;17.11%),and extremely severe(n=48;3.99%)MGL groups.MGL was significantly larger in female than in male(P=0.006).The degree of MGL also significantly differed in age(P<0.001)and the more numbers of mites with severity(P<0.001).Multivariate disordered multinomial logistic regression analysis identified that female sex,older age,secretory symptoms,and a large number of mites were risk factors for MGL(P<0.05).CONCLUSION:Patients with MGL are more likely to be older,female,more numbers of mites,and increased secretion.

UV,five wavelengths fusion and electrochemical fingerprints combined with antioxidant activity for quality control of antiviral mixture

Aiming to ensure the consistency of quality control of Traditional Chinese Medicines(TCMs),a combination method of high-performance liquid chromatography(HPLC),ultraviolet(UV),electrochemical(EC)was developed in this study to comprehensively evaluate the quality of Antiviral Mixture(AM),and Comprehensive Linear Quantification Fingerprint Method(CLQFM)was used to process the data.Quantitative analysis of three active substances in TCM was conducted.A fivewavelength fusion fingerprint(FWFF)was developed,using second-order derivatives of UV spectral data to differentiate sample levels effectively.The combination of HPLC and UV spectrophotometry,along with electrochemical fingerprinting(ECFP),successfully evaluated total active substances.Ultimately,a multidimensional profiling analytical system for TCM was developed.

LncRNA-MEG3对胃癌生物学特性及铂类化疗敏感性的研究

目的探讨Lnc RNA-MEG3对胃癌增殖、凋亡及顺铂化疗敏感性的影响。方法以人正常胃黏膜上皮细胞GES1作为对照细胞,实时荧光定量聚合酶链反应(qRT-PCR)检测胃癌MKN28、SGC7901、AGS及BGC823细胞中LncRNA-MEG3的表达;将过表达MEG3的质粒转染BGC823细胞作为pcDNA3.1-MEG3组,转染空白质粒的阴性对照作为pcDNA3.1组,同时设置Control组;将BGC823细胞分为pcDNA3.1组、pcDNA3.1-MEG3组、顺铂组及pcDNA3.1-MEG3+顺铂组。qRT-PCR检测转染48 h后细胞中LncRNA-MEG3的表达;pcDNA3.1-MEG3、顺铂单独或共同处理BGC823细胞,细胞计数试剂盒法及流式细胞仪分别检测细胞活力及凋亡率;Western blotting检测STAT3、磷酸化的信号转导与转录因子3(p-STAT3)、Cyclin D1和Bcl-2的表达。结果胃癌细胞中LncRNA-MEG3的表达均低于GES1细胞(P <0.05);4组LncRNA-MEG3相对表达量比较,差异有统计学意义(P <0.05);pcDNA3.1-MEG3组和顺铂组Cyclin D1、Bcl-2及p-STAT3的蛋白表达低于pcDNA3.1组(P <0.05),细胞凋亡率高于pcDNA3.1组(P <0.05)。结论胃癌细胞中LncRNA-MEG3表达降低,过表达LncRNA-MEG3可降低胃癌细胞活力并诱导细胞凋亡,增加顺铂的化疗敏感性,其机制与下调STAT3信号通路有关。

气体–原油分子扩散系数实验研究进展

在注气驱油的过程中,当气体与原油接触时,气体与原油间就会发生传质现象,改变原油流体性质,改善原油流动能力,从而提高采收率。分子扩散系数是一个描述气–油体系传质率的重要参数,目前多以间接方法来测试分子扩散系数。确定扩散系数两个关键问题是:1) 确定合理的实验方法;2) 选择准确的模型来解释实验数据。本文综述了气–油分子扩散系数的实验及模型研究进展,包括确定分子扩散系数的实验方法和分子扩散系数的影响因素。

Improving oil recovery in the CO2 flooding process by utilizing nonpolar chemical modifiers

By means of experiments of C02 miscibility with crude oil, four nonpolar chemicals were evaluated in order to enhance the miscibility of C02 with crude oil. Through pre-slug injection and joint injection of toluene in CO2, crude oil displacement experiments in the slim-tube were conducted to investigate effects of the toluene- enhanced C02 flooding under simulated subterranean reservoir conditions. Experimental results showed that toluene can enhance extraction of oil into C02 and dissolution of C02 into oil with the increment of 251% and 64% respectively. Addition of toluene can obviously improve the oil recovery in either pre-slug injection or joint injection, and the crude oil recovery increased with the increase of the toluene concentration. The oil recov- ery can increase by 22.5% in pre-slug injection with the high toluene concentration. Pre-slug injection was recom- mended because it can consume less toluene than joint injection. This work could be useful to development and application of the CO） flooding in the oil recoverv as well as CO2 emission reduction.

Investigation of flue gas water-alternating gas (flue gas–WAG) injection for enhanced oil recovery and multicomponent flue gas storage in the post-waterflooding reservoir

Flue gas fooding is one of the important technologies to improve oil recovery and achieve greenhouse gas storage.In order to study multicomponent fue gas storage capacity and enhanced oil recovery(EOR)performance of fue gas water-alternating gas(fue gas-WAG)injection after continuous waterfooding in an oil reservoir,a long core fooding system was built.The experimental results showed that the oil recovery factor of fue gas-WAG fooding was increased by 21.25%after continuous waterfooding and fue gas-WAG fooding could further enhance oil recovery and reduce water cut signifcantly.A novel material balance model based on storage mechanism was developed to estimate the multicomponent fue gas storage capacity and storage capacity of each component of fue gas in reservoir oil,water and as free gas in the post-waterfooding reservoir.The ultimate storage ratio of fue gas is 16%in the fue gas-WAG fooding process.The calculation results of fue gas storage capacity showed that the injection gas storage capacity mainly consists of N_(2) and CO_(2),only N_(2) exists as free gas phase in cores,and other components of injection gas are dissolved in oil and water.Finally,injection strategies from three perspectives for fue gas storage,EOR,and combination of fue gas storage and EOR were proposed,respectively.

A Practice Guide of Software Aging Prediction in a Web Server Based on Machine Learning

In the past two decades, software aging has been studied by both academic and industry communities. Many scholars focused on analytical methods or time series to model software aging process. While machine learning has been shown as a very promising technique in application to forecast software state: normal or aging. In this paper, we proposed a method which can give practice guide to forecast software aging using machine learning algorithm. Firstly, we collected data from a running commercial web server and preprocessed these data. Secondly, feature selection algorithm was applied to find a subset of model parameters set. Thirdly, time series model was used to predict values of selected parameters in advance. Fourthly, some machine learning algorithms were used to model software aging process and to predict software aging. Fifthly, we used sensitivity analysis to analyze how heavily outcomes changed following input variables change. In the last, we applied our method to an IIS web server. Through analysis of the experiment results, we find that our proposed method can predict software aging in the early stage of system development life cycle.

Magnetic field‐enhanced water splitting enabled by bifunctional molybdenum‐doped nickel sulfide on nickel foam

Herein,we report bifunctional molybdenum-doped nickel sulfide on nickel foam(Mo-NiS_(x)/NF)for magnetic field-enhanced overall water splitting under alkaline conditions.Proper doping of Mo can lead to optimization of the electronic structure of NiS_(x),which accelerates the dissociation of H2O and the adsorption of OH−in the hydrogen evolution reaction(HER)and the oxygen evolution reaction(OER)processes,respectively.In addition,the magnetically active Mo-NiS_(x)/NF can further enhance the HER and OER activity under an applied magnetic field due to the magnetoresistance effect and the ferromagnetic(FM)exchange-field penetration effect.As a result,Mo-NiS_(x)/NF requires low overpotentials of 307 mV at 50mA cm^(−2)(for OER)and 136 mV at 10mA cm^(−2)(for HER)under a magnetic field of 10000 G.Furthermore,the electrolytic cell constructed by the bifunctional Mo-NiS_(x)/NFs as both the cathode and the anode shows a low cell voltage of 1.594 V at 10 mA cm^(−2)with optimal stability over 60 h under the magnetic field.Simultaneous enhancement of the HER and OER processes by an external magnetic field through rational design of electrocatalysts might be promising for overall water splitting applications.

Automated spectral classification using template matching

An automated spectral classification technique for large sky surveys is proposed. We firstly perform spectral line matching to determine redshift candidates for an observed spectrum, and then estimate the spectral class by measuring the similarity between the observed spectrum and the shifted templates for each redshift candidate. As a byproduct of this approach, the spectral redshift can also be obtained with high accuracy. Compared with some approaches based on computerized learning methods in the literature, the proposed approach needs no training, which is time-consuming and sensitive to selection of the training set. Both simulated data and observed spectra are used to test the approach; the results show that the proposed method is efficient, and it can achieve a correct classification rate as high as 92.9%, 97.9% and 98.8% for stars, galaxies and quasars, respectively.

Generating routes for autonomous driving in vehicle-to-infrastructure communications

The study of vehicular networks has attracted considerable interest in academia and the industry.In the broad area,connected vehicles and autonomous driving are technologies based on wireless data communication between vehicles or between vehicles and infrastructures.A Vehicle-to-Infrastructure(V2I)system consists of communications and computing over vehicles and related infrastructures.In such a system,wireless sensors are installed in some selected points along roads or driving areas.In autonomous driving,it is crucial for a vehicle to figure out the ideal routes by the communications between its equipped sensors and infrastructures then the vehicle is automatically moving along the routes.In this paper,we propose a Bezier curve based recursive algorithm,which effectively creates routes for vehicles through the communication between the On-Board Unit(OBU)and the Road-Side Units(RSUs).In addition,this approach generates a very low overhead.We conduct simulations to test the proposed algorithm in various situations.The experiment results demonstrate that our algorithm creates almost ideal routes.

Gas channeling control with an in-situ smart surfactant gel during water-alternating-CO_(2) enhanced oil recovery

Undesirable gas channeling always occurs along the high-permeability layers in heterogeneous oil reservoirs during water-alternating-CO_(2)(WAG)flooding,and conventional polymer gels used for blocking the“channeling”paths usually suffer from either low injectivity or poor gelation control.Herein,we for the first time developed an in-situ high-pressure CO_(2)-triggered gel system based on a smart surfactant,N-erucamidopropyl-N,N-dimethylamine(UC22AMPM),which was introduced into the aqueous slugs to control gas channeling inWAG processes.The water-like,low-viscosity UC22AMPM brine solution can be thickened by high-pressure CO_(2) owing to the formation of wormlike micelles(WLMs),as well as their growth and shear-induced structure buildup under shear flow.The thickening power can be further potentiated by the generation of denser WLMs resulting from either surfactant concentration augmentation or a certain range of heating,and can be impaired via pressurization above the critical pressure of CO_(2) because of its soaring solvent power.Core flooding tests using heterogeneous cores demonstrated that gas channeling was alleviated by plugging of high-capacity channels due to the in-situ gelation of UC22AMPM slugs upon their reaction with the pre-or post-injected CO_(2) slugs under shear flow,thereupon driving chase fluids into unrecovered low-permeability areas and producing an 8.0% higher oil recovery factor than the conventional WAG mode.This smart surfactant enabled high injectivity and satisfactory gelation control,attributable to low initial viscosity and the combined properties of one component and CO_(2)-triggered gelation,respectively.This work could provide a guide towards designing gels for reducing CO_(2) spillover and reinforcing the CO_(2) sequestration effect during CO_(2) enhanced oil recovery processes.

Synthesis of novel methotrexate derivatives with inhibition activity of nitric oxide synthase

Seventeen 4-alkylamino/arylamino-substituted methotrexate （MTX） derivatives 6a-14a were designed and synthesized. Their inhibition activities against inducible nitric oxide synthase （iNOS） were evaluated in vitro. The pharmacological results showed that most of the prepared compounds displayed the potent inhibitory effects on iNOS.

A Practical Intrusion Detection System for Internet of Vehicles

Internet of Vehicles(henceforth called IoV) is a public network system and high-value target for intrusions that may cause efficiency issues, privacy leakages or even physical damage. Conventional intrusion detection methods are normally designed for the Internet infrastructures which cannot directly apply in the context of IoV. This work proposes an FPGA based intrusion detection method that can not only achieve real-time scanning performance but also be applied in vehicular environment. We evaluate our scheme on a Xilinx FPGA based platform. Experiments show that the proposed system can achieve a throughput of more than 39 Gbps on existing FPGA platform which is about 15% higher than state-of-the-art techniques,and the total power consumption for the prototype is about 7.5 w. Moreover, the processing latency of the prototype is about 4 us and is about one sixtieth part of the popular software IDS systems.

Upregulation of microRNA-451a improves endothelial cell function in atherosclerosis by direct targeting of macrophage migration inhibitory factor

This study aims to detect the expression of selected circulating microRNAs(miRNA),including miRNA-451a,miRNA-486-5p and miR-10b-5p,and their prospective roles as biomarkers in patients with atherosclerosis.For this purpose,levels of miRNAs were detected by real-time quantitative polymerase chain reaction(RT-qPCR)in case(N=30)and healthy control(N=30)groups.Receiver operating characteristic(ROC)curve analysis was carried out to evaluate the diagnostic ability of miRNAs.The correlations of miR-451a with lipid parameters were evaluated using Pearson’s correlation coefficients.HUVEC tested by ox-LDL was used as a cellular model of atherosclerosis.Cell viability and apoptosis were detected by methyl thiazolyl tetrazolium(MTT)and flow cytometry(FC)assays.Luciferase assay was used to determine the miRNA binding site on target genes.The results showed that miRNA-451a expression level was significantly lower in patients than controls.ROC curve analysis showed that the areas under the curve(AUC)of plasma miRNA-451a was 0.90.The miRNA-451a expression level exhibited significant negative correlations with cholesterol(TC),triglyceride(TG),and low-density lipoprotein(LDL).Besides,miRNA-451a specifically binds to the 3’UTR of macrophage migration inhibitory factor(MIF)and mediated the cell proliferation and apoptosis of HUVECs exposed to ox-LDL.Furthermore,overexpression of miRNA-451a promoted the proliferation and alleviated apoptosis of HUVECs exposed to ox-LDL,while this result was attenuated by macrophage migration inhibitory factor(MIF)overexpression.Therefore,miRNA-451a could be considered as a potential biomarker for atherosclerosis and miRNA-451a might contribute to regulating atherosclerosis through targeting MIF.

Radio frequency interference mitigation using pseudoinverse learning autoencoders

Radio frequency interference(RFI)is an important challenge in radio astronomy.RFI comes from various sources and increasingly impacts astronomical observation as telescopes become more sensitive.In this study,we propose a fast and effective method for removing RFI in pulsar data.We use pseudo-inverse learning to train a single hidden layer auto-encoder(AE).We demonstrate that the AE can quickly learn the RFI signatures and then remove them from fast-sampled spectra,leaving real pulsar signals.This method has the advantage over traditional threshold-based filter method in that it does not completely remove contaminated channels,which could also contain useful astronomical information.

Psychological trauma,posttraumatic stress disorder and traumarelated depression:A mini-review

There are various types of traumatic stimuli,such as catastrophic events like wars,natural calamities like earthquakes,and personal trauma from physical and psychological neglect or abuse and sexual abuse.Traumatic events can be divided into type I and type II trauma,and their impacts on individuals depend not only on the severity and duration of the traumas but also on individuals’self-evaluation of the traumatic events.Individual stress reactions to trauma include posttraumatic stress disorder(PTSD),complex PTSD and trauma-related depression.Trauma-related depression is a reactive depression with unclear pathology,and depression occurring due to trauma in the childhood has gained increasing attention,because it has persisted for a long time and does not respond to conventional antidepressants but shows good or partial response to psychotherapy,which is similar to the pattern observed for PTSD.Because trauma-related depression is associated with high risk of suicide and is chronic with a propensity to relapse,it is necessary to explore its pathogenesis and therapeutic strategy.

ⅢA型格子状角膜营养不良患者角膜前弹力层神经侵噬现象的自身对照研究

目的:采用角膜激光共焦显微镜研究分析ⅢA型格子状角膜营养不良(LCD)患者的角膜神经侵噬现象,对10a连续观察图像数据进行定量分析后进行自身对照研究。方法:收集2007-09/2018-12确诊的ⅢA型LCD患者10例13眼,采用角膜激光共焦显微镜对患者的角膜进行连续的扫描检测,观察分析其前弹力层神经的检查情况。结果:随着观察时间的延长,ⅢA型LCD患者的正常角膜基质神经(0级神经)逐渐减少,Ⅰ级~Ⅴ级受累神经(淀粉样物包裹的神经纤维)逐渐增多,提示ⅢA型LCD患者角膜前弹力层神经侵噬情况(淀粉样沉积物)是随着时间延长而逐渐加重的。结论:ⅢA型LCD患者角膜前弹力层神经存在着嗜神经现象,随着病变的加重而逐渐加重,该病变能从侧面解释该型LCD复发性上皮损害的情况。利用角膜激光共焦显微镜对ⅢA型LCD患者进行连续的观察,能够很好地了解该病变的发展情况,解释其临床表现。

Density functional theory study of structural stability for gas hydrate

Using the first-principles method based on the density functional theory（DFT）,the structures and electronic properties of different gas hydrates（CO2,CO,CH4,and H2） are investigated within the generalized gradient approximation.The structural stability of methane hydrate is studied in this paper.The results show that the carbon dioxide hydrate is more stable than the other three gas hydrates and its binding energy is-2.36 e V,and that the hydrogen hydrate is less stable and the binding energy is-0.36 e V.Water cages experience repulsion from inner gas molecules,which makes the hydrate structure more stable.Comparing the electronic properties of two kinds of water cages,the energy region of the hydrate with methane is low and the peak is close to the left,indicating that the existence of methane increases the stability of the hydrate structure.Comparing the methane molecule in water cages and a single methane molecule,the energy of electron distribution area of the former is low,showing that the filling of methane enhances the stability of hydrate structure.

Study of the Seepage Mechanism in Thick Heterogeneous Gas Reservoirs

The seepage mechanism plays a crucial role in low-permeability gas reservoirs.Compared with conventional gas reservoirs,low-permeability sandstone gas reservoirs are characterized by low porosity,low permeability,strong heterogeneity,and high water saturation.Moreover,their percolation mechanisms are more complex.The present work describes a series of experiments conducted considering low-permeability sandstone cores under pressuredepletion conditions(from the Xihu Depression in the East China Sea Basin).It is shown that the threshold pressure gradient of a low-permeability gas reservoir in thick layers is positively correlated with water saturation and negatively correlated with permeability and porosity.The reservoir stress sensitivity is related to permeability and rock composition.Stress sensitivity is generally low when permeability is high or in the early stage of gas reservoir development.It is also shown that in sand conglomerates,especially the more sparsely filled parts,the interstitial materials among the conglomerates can be rapidly dislodged from the skeleton particles under stress.This material can therefore disperse,migrate,and block the pore throat producing serious,stress-sensitive damage.