Deflagration characteristics of freely propagating flames in magnesium hydride dust clouds

The flame propagation processes of MgH_(2)dust clouds with four different particle sizes were recorded by a high-speed camera.The dynamic flame temperature distributions of MgH_(2)dust clouds were reconstructed by the two-color pyrometer technique,and the chemical composition of solid combustion residues were analyzed.The experimental results showed that the average flame propagation velocities of 23μm,40μm,60μm and 103μm MgH_(2)dust clouds in the stable propagation stage were 3.7 m/s,2.8 m/s,2.1 m/s and 0.9 m/s,respectively.The dust clouds with smaller particle sizes had faster flame propagation velocity and stronger oscillation intensity,and their flame temperature distributions were more even and the temperature gradients were smaller.The flame structures of MgH_(2)dust clouds were significantly affected by the particle sinking velocity,and the combustion processes were accompanied by micro-explosion of particles.The falling velocities of 23μm and 40μm MgH_(2)particles were 2.24 cm/s and 6.71 cm/s,respectively.While the falling velocities of 60μm and 103μm MgH_(2)particles were as high as 15.07 cm/s and 44.42 cm/s,respectively,leading to a more rapid downward development and irregular shape of the flame.Furthermore,the dehydrogenation reaction had a significant effect on the combustion performance of MgH_(2)dust.The combustion of H_(2)enhanced the ignition and combustion characteristics of MgH_(2)dust,resulting in a much higher explosion power than the pure Mg dust.The micro-structure characteristics and combustion residues composition analysis of MgH_(2)dust indicated that the combustion control mechanism of MgH_(2)dust flame was mainly the heterogeneous reaction,which was affected by the dehydrogenation reaction.

Review of Plant Essential Oils for Plant Pests Management

This paper reviews the origins and classification of plant essential oil resources,along with prevalent extraction techniques for their active constituents.By integrating insights on the utilization of plant essential oils for plant pest management,the comprehensive analysis reveals multiple functionalities exhibited by plant essential oils,including fumigation,contact toxicity,repellent action,antifeedant activity,and growth inhibition.Furthermore,the paper highlights the challenges associated with plant essential oils in plant protection and outlines future research directions,aiming to offer valuable insights for the advancement of botanical insecticides.

Identification and Typing of Respiratory Adenoviruses in Guangzhou, Southern China Using a Rapid and Simple Method

Human adenoviruses (HAdVs), especially HAdV-B3, -E4 and -B7, are associated with Acute Respiratory Disease in Chinese children, and occasionally in adults. In order to establish and document the profiles of the respiratory adenovirus pathogen among children in Guangzhou, Southern China, a rapid, simple and practical method for identification and typing of respiratory adenoviruses was developed and evaluated. One pair of universal PCR primers was designed according to the conserved region of the hexon gene, which can detect not only HAdV-B3, -E4 and -B7, but also HAdV-B14, -F40 and -F41, with a specific 300bp PCR product. Three pairs of type-specific PCR primers were also designed according to the hypervariable regions of the hexon gene to type HAdV-B3, -E4 and -B7 by three independent PCR reactions, making it easy to optimize the PCR conditions. By using this method, one hundred throat swab specimens collected during Oct 2010 to Dec 2011 and suspected of being positive for adenoviral infection were identified and typed for adenoviruses. Of these samples, fifty-five were adenovirus-positive. The most common HAdV type was HAdV-B3, identified in 92.7% of samples, which is not only consistent with the data reported in 2004-2006, but also consistent with the recent report in Hangzhou, eastern China, indicating that HAdV-B3 has been circulating in Guangzhou, and maybe in eastern China, for many years. The method for the respiratory adenovirus identification and typing we developed is rapid, simple and practical, which has a potential in the real-time surveillance of circulating adenovirus strains and also to provide etiological evidence for the adenovirus-relative disease control and prevention in China.

Crucial control on magmatic-hydrothermal Sn deposit in the Tengchong block,SW China:Evidence from magma differentiation and zircon geochemistry

Magmatic-hydrothermal Sn deposits are commonly associated with high silica magmas,but why most global high silica granites do not bear economic Sn ore grades remains unclear.Two crucial factors controlling magmatic-hydrothermal Sn mineralization,including advanced fractionation and depressurization-induced rapid cooling,were revealed in the case study of the Guyong granitic pluton linked with the Xiaolonghe Sn deposit,in the Tengchong block,SW China.The Guyong granitic pluton comprises three petrological facies:less evolved biotite syenogranite,evolved alkali granite and leucogranite,and highly evolved facies(the protolith of greisenized granite).Similar crystallization ages(~77 Ma)and gradual contact between different petrological facies indicate the Guyong granitic pluton records a continuous fractionation process.Monte Carlo-revised Rayleigh fractionation model suggests the fractionation degree of the Guyong pluton is markedly high(>87 wt.%)that can only be achieved by a high initial water(≥4 wt.%)content in the parent granitic magma revealed by rhyolite-MELTS calculation.Advanced degree fractionation causes the first Sn enrichment but it also significantly increases the viscosity of evolved magmas,suppressing the exsolution and transport of hydrothermal fluids.Hence,it must be compensated by the second critical factor:depressurization-induced rapid cooling,reflected by the occurrence of highly metamict zircons in the greisenized granite.The highly metamict feature,indicated by the large full width at half maximum(FWHM)values of zirconν3(SiO_(4)) peak(>19.5 cm^(-1)),suggests these zircons do not experience thermal annealing but rapidly ascend into a shallow cooling environment.Depressurization-induced rapid cooling facilitates exsolution and transport of hydrothermal fluids,interacting with wall rocks and resulting in Sn mineralization.

以学生为中心的仪器分析实验线上线下混合式教学探索与实践

针对传统实验教学方法中存在的问题与不足,以仪器分析实验课程为例,提出了以学生为中心的混合式教学设计,通过分层教学满足个性化培养需求。基于大夏学堂在线学习平台,通过线上、线下环环相扣的教学活动有效激发学生的学习兴趣与主动性,引导学生内化知识,培养分析解决问题的高阶思维与综合能力,促进学生全面发展。

Dynamic analysis of 10 components of the Chinese herbal compound Wuzhuyu-tang absorbed into rat plasma

To clarify the active components of Wuzhuyu-tang, this study analyzed dynamic changes of 10 ingredients of Wuzhuyu-tang in plasma using combination high performance liquid chromatography-mass spectrometry after oral administration in rats. The results showed that seven ingredients were detected in portal vein plasma after oral administration of 16.3 or 8.15 g/kg equivalent of raw material of Wuzhuyu-tang extract. The absorption rate of limonin, evodiamine, gingerol （6-Gi）, and ginsenoside-Rg1 was greater than that of isorhamnetin-3-O-β-D-glucosyl （6″→1″′）-α-L-rhamnoside, ginsenoside-Rb1 （Rb1）, and ginsenoside-Re （Re）. The time most elements were absorbed into the blood was 30 to 60 minutes after administration. Re, 6-Gi and Rb1 were metabolized faster. The results suggest that the seven ingredients described above are the active components for treating migraines.

Platelet factor 4 induces bone loss by inhibiting the integrinα5-FAK-ERK pathway

Background:The effect of platelet factor 4(PF4)on bone marrow mesenchymal stem cells(BMMSCs)and osteoporosis is poorly understood.Therefore,this study aimed to evaluate the effects of PF4-triggered bone destruction in mice and determine the underlying mechanism.Methods:First,in vitro cell proliferation and cell cycle of BMMSCs were assessed using a CCK8 assay and flow cytometry,respectively.Osteogenic differentiation was confirmed using staining and quantification of alkaline phosphatase and Alizarin Red S.Next,an osteoporotic mouse model was established by performing bilateral ovariectomy(OVX).Furthermore,the PF4 concentrations were obtained using enzymelinked immunosorbent assay.The bone microarchitecture of the femur was evaluated using microCT and histological analyses.Finally,the key regulators of osteogenesis and pathways were investigated using quantitative real-time polymerase chain reaction and Western blotting.Results:Human PF4 widely and moderately decreased the cell proliferation and osteogenic differentiation ability of BMMSCs.Furthermore,the levels of PF4 in the serum and bone marrow were generally increased,whereas bone microarchitecture deteriorated due to OVX.Moreover,in vivo mouse PF4 supplementation triggered bone deterioration of the femur.In addition,several key regulators of osteogenesis were downregulated,and the integrinα5-focal adhesion kinase-extracellular signalregulated kinase(ITGA5-FAK-ERK)pathway was inhibited due to PF4 supplementation.Conclusions:PF4 may be attributed to OVX-i nduced bone loss triggered by the suppression of bone formation in vivo and alleviate BMMSC osteogenic differentiation by inhibiting the ITGA5-FAK-ERK pathway.

The effects of irreversible electroporation triggering anti-tumor immunity and the value of its combination with immunotherapy

Recently,interventional ablation techniques have gained prominence in tumor treatment guidelines and complement traditional approaches,such as surgery,chemotherapy,and radiotherapy.Conventional ablation techniques,such as microwave,radiofrequency,and cryoablation,have been used;however,they have certain limitations,including the risk of damaging surrounding normal tissues and the heat sink effect caused by tumor blood flow.1 Irreversible electroporation(IRE),an ablation technology independent of thermal energy,is a promising alternative.2 Clinical studies have demonstrated IRE's efficacy in treating tumors,such as pancreatic and liver tumors.3 Recent research has shown that IRE can elicit specific anti-tumor immune responses in the body.5 IRE also plays a crucial role in eliminating residual tumor cells postoperatively and preventing tumor recurrence.

日频投资者情绪对A股短线收益率的影响研究

2023年8月3日,经济日报发文认为,让居民通过股票、基金等渠道参与投资并获取收益,能够将消费意愿转化为消费能力,因此研究A股短线收益率的影响因素具有重要的指导意义。文章基于A股市场的日频数据,在前人研究基础上创新性补充了昨日涨停表现、高度等研究较少的间接度量指标,并结合直接度量指标百度指数,采用主成分分析法构建A股日频投资者情绪指标,分析了投资者情绪与A股短线收益率之间的关系。实证分析结果表明:1)投资者情绪对A股短线收益率具有显著影响;2)该情绪指标对近期强势指数收益率、国证2000指数收益率影响较大,对创业板指数的影响较小。这些结论为投资者理性投资和监管者稳定市场环境提供了重要的参考,有助于他们更好地理解和应对市场波动。

Multicolor upconversion reversible modulations in YNbO_(4):Er^(3+)/Tm^(3+)/Yb^(3+) photochromic materials

Photochromic materials with multicolor upconversion reversible modulations are attractive in optical switching devices.Herein,the fabricated YNbO_(4):Er^(3+)/Tm^(3+)/Yb^(3+) materials exhibit excellent photochromism and multicolor upconversion properties from green,red to near infrared(NIR) emissions with increasing Yb concentrations.Reversible multiband upconversion modulations are achieved by alternating light(365 and 405 nm) or thermal stimuli.After 365 nm irradiation,the luminescence color changes from yellow to red,the luminescent photoswitching contrast reaches up to 86.21%(green),82.12%(red) and 77.38%(NIR) in the Y_(0.83)Er_(0.01)Tm_(0.01)NbO_(4):0.15 Yb sample.Besides,the upconversion emission intensity before and after photochromic reaction shows remarkable change in a wide temperature range of 298-718 K.These results indicate that the Er^(3+)/Tm^(3+)/Yb^(3+) tri-doped YNbO_(4) materials can be a good candidate in optical switching and data storage applications.

Measurement of the neutron total cross section of^(9)Be at the Back-n white neutron source of CSNS

The neutron total cross section data of^(9)Be are essential in the nuclear structure model research of light nuclei and nuclear power installations.The neutron total cross section of^(9)Be in the 0.3 eV−120 MeV energy region has been measured using time-of-flight and transmission methods with the Neutron Total Cross Sectional Spectrometer(NTOX)based on the multi-cell fast fission chamber at the China Spallation Neutron Source(CSNS)-Back-n white neutron source(Back-n).The fission count-neutron energy distributions of ^(235)U and ^(238)U without samples and with Be samples with three thicknesses were measured in the double-bunch operation mode for a beam power of 100 kW.The Bayesian method was used to eliminate the influence of the double-bunch problem on neutron measurement in the energy region above 10 keV.The neutron total cross section of^(9)Be results was consistent with ENDF/B-VIII.0 evaluation library data in the 0.3 eV−20 MeV energy region.In the energy ranges of 0.3 eV to 10 keV and 0.01 to 20 MeV,the deviations between our results and the evaluation results of ENDF/B-VIII.0 were within 2.5%and 15%,respectively.In the resonance energy region,the measured resonance energies in our experiment were 0.63,0.82,and 2.8 MeV,respectively.The results showed that the total cross section uncertainties of three Be samples were within 2.2%in the energy region below 1 MeV.The total cross section uncertainty of 30 mm Be from ^(235)U was the smallest and less than 5%in the energy region of 0.3 eV−120 MeV.The results of this experiment can provide technical support for further data analysis and related nuclear data evaluation.

A time-dependent luminescent phosphor of Na_(2)Ba_(2)Si_(2)O_(7):Eu for multi-level encryption and dynamic information display

Photo-stimuli responsive materials show great potential in the fields of information encryption and storage due to their distinctive spatial or temporal color changes.However,the conventional single or multi-color static outputs by light stimulus difficulty meet practical requirements for high-security optical storage technologies.Here,a novel dynamic irradiation-responsive phosphor of Na_(2)Ba_(2)Si_(2)O_(7):Eu is demonstrated,exhibiting high storage stability and convenient readout behaviors.The inherent Eu^(2+)luminescence can be dynamically tuned,instantly read out,and conveniently erased by controlling irradiation duration of a portable diode laser(365 nm).The modulation mechanism is unraveled by optically induced oxidation reactions of Eu^(2+)→Eu^(3+)and defects as killer centers.The excellent luminescence modulation degree(ΔR_(t)=89.5%)and the accompanying larger color contrast enable the creation of invisible optical codes with multi-level encryption in bright or dark field.These results indicate potential applications of Na_(2)Ba_(2)Si_(2)O_(7):-based materials in information encryption and invisible optical storage,and are expected to expand more investigations on optically induced PL modulation behaviors based on mixed valences and defects.

Tunable supra-transmission of a stacked miura-origami basedmeta-structure

The origami-based meta-structure has wide application in areas such as energy and wave transmission.Existingresearch has demonstrated the occurrence of supra-transmission in origami meta-structures and revealed its un-derlying mechanism.However,studies on how to regulate the phenomenon of supra-transmission are still verylimited.In this work,we choose the meta-structure composed of stacked Miura-ori(SMO)as the subject.TheSMO unit possesses two topologically distinct stable configurations,enabling the meta-structure to possess a richvariety of periodic layouts.Based on the established equivalent dynamic model of the SMO-based meta-structure,we employ numerical simulation methods and find that the supra-transmission threshold could be adjusted bytuning the periodic layout of the meta-structure.Furthermore,the probability of supra-transmission is also highlydependent on the periodic layout.Increasing the number of SMO units under the bulged-out configuration in eachperiodic layout decreases the likelihood of supratransmission occurring.The findings of this study yield an ex-tensive array of foundational insights into the wave dynamics of origami structures.Furthermore,these insightstranslate into practical guidelines for designing origami-based meta-structure with tunable and programmabledynamic characteristics.

固态发酵下酵母自溶的工艺优化

固态下酵母自溶可以有效促进菌体内多种活性物质的释放,进而提高酵母类产品的品质。通过优化自溶温度、自溶时间及自溶促进剂锌离子浓度以获得固态发酵下酵母自溶的最佳工艺,对固态发酵物料中游离氨基酸、可溶性蛋白、α-氨基氮含量和A_(260)/A_(280)等指标的分析来确定固态酵母自溶工艺条件,在此基础上以自溶温度40℃、50℃、55℃;作用时间12、18、24 h;锌离子添加浓度2、4、8 mg/kg设置L_9(3~3)正交试验,进一步优化固态酵母自溶的工艺参数。结果表明酵母自溶的最佳工艺条件为:自溶温度55℃、作用时间18 h、锌离子浓度2 mg/kg,此时其可溶性蛋白含量可达9.31 mg/g、游离氨基酸14.36 mg/g、α-氨基氮10.16μg/g、A_(260)/A_(280)为1.73。经工艺优化后,可显著提高酵母自溶产物可溶性蛋白、游离氨基酸和α-氨基氮的含量,从而明显提高了复合菌培养物的品质。

Progress of Jinping Underground laboratory for Nuclear Astrophysics(JUNA)

Jinping Underground laboratory for Nuclear Astrophysics(JUNA) will take the advantage of the ultra-low background of CJPL lab and high current accelerator based on an ECR source and a highly sensitive detector to directly study for the first time a number of crucial reactions occurring at their relevant stellar energies during the evolution of hydrostatic stars. In its first phase, JUNA aims at the direct measurements of^(25)Mg(p,γ)^(26)Al,^(19)F(p,α)^(16)O,^(13)C(α,n)^(16)O and ^(12)C(α,γ)^(16)O reactions. The experimental setup,which includes an accelerator system with high stability and high intensity, a detector system, and a shielding material with low background, will be established during the above research. The current progress of JUNA will be given.

COVID-19: Antiviral Agents, Antibody Development and Traditional Chinese Medicine

The World Health Organization(WHO) has declared coronavirus disease 2019(COVID-19) is the first pandemic caused by coronavirus named severe acute respiratory syndrome coronavirus 2(SARS-CoV-2). Currently, there is no effective anti-SARS-CoV-2 drug approved worldwide for treatment of patients with COVID-19. Therapeutic options in response to the COVID-19 outbreak are urgently needed. To facilitate the better and faster development of therapeutic COVID-19 drugs, we present an overview of the global promising therapeutic drugs, including repurposing existing antiviral agents,network-based pharmacology research, antibody development and traditional Chinese medicine. Among all these drugs,we focus on the most promising drugs(such as favipiravir, tocilizumab, SARS-CoV-2 convalescent plasma, hydroxychloroquine, Lianhua Qingwen, interferon beta-1 a, remdesivir, etc.) that have or will enter the final stage of human testing—phase Ⅲ–Ⅳ clinical trials.

Hypoxia signaling in human health and diseases:implications and prospects for therapeutics

Molecular oxygen(O2)is essential for most biological reactions in mammalian cells.When the intracellular oxygen content decreases,it is called hypoxia.The process of hypoxia is linked to several biological processes,including pathogenic microbe infection,metabolic adaptation,cancer,acute and chronic diseases,and other stress responses.The mechanism underlying cells respond to oxygen changes to mediate subsequent signal response is the central question during hypoxia.Hypoxia-inducible factors(HIFs)sense hypoxia to regulate the expressions of a series of downstream genes expression,which participate in multiple processes including cell metabolism,cell growth/death,cell proliferation,glycolysis,immune response,microbe infection,tumorigenesis,and metastasis.Importantly,hypoxia signaling also interacts with other cellular pathways,such as phosphoinositide 3-kinase(PI3K)-mammalian target of rapamycin(mTOR)signaling,nuclear factor kappa-B(NF-κB)pathway,extracellular signal-regulated kinases(ERK)signaling,and endoplasmic reticulum(ER)stress.This paper systematically reviews the mechanisms of hypoxia signaling activation,the control of HIF signaling,and the function of HIF signaling in human health and diseases.In addition,the therapeutic targets involved in HIF signaling to balance health and diseases are summarized and highlighted,which would provide novel strategies for the design and development of therapeutic drugs.

HIF-1α promotes SARS-CoV-2 infection and aggravates inflammatory responses to COVID-19

Cytokine storm induced by Severe Acute Respiratory Syndrome Coronavirus 2(SARS-CoV-2)is a major pathological feature of Coronavirus Disease 2019(COVID-19)and a crucial determinant in COVID-19 prognosis.Understanding the mechanism underlying the SARS-CoV-2-induced cytokine storm is critical for COVID-19 control.Here,we identify that SARS-CoV-2 ORF3a and host hypoxia-inducible factor-1α(HIF-1α)play key roles in the virus infection and pro-inflammatory responses.

The C_(6)D_(6)detector system on the Back-n beam line of CSNS

Introduction The neutron capture cross sections are very important in the field of nuclear device design and basic physics research.Hydrogen-free liquid scintillator such as C_(6)D_(6)detectors are widely used in the neutron capture cross-sectional measurements for the low neutron sensitivity and fast time response.The Back-n white neutron source at China Spallation Neutron Source is the first spallation white neutron source in China,and it is suitable for neutron capture cross-sectional measurement.Materials and methods A C_(6)D_(6)detector system was built in the Back-n experimental station.The pulse height weighting technique was used to determine the system’s detection efficiency.The response to gamma rays of the C_(6)D_(6)detector was measured,and the energy resolution function was determined.Monte Carlo simulation with Geant4 code was carried out to get the weighting function of this C_(6)D_(6)detector system.Additionally,the systematic uncertainty of the weighting function was also determined.Conclusion According to the experimental and simulation results,this C_(6)D_(6)detector system can be used to measure neutron capture cross section.

Improved breakdown strength and energy density of polyimide composites by interface engineering between BN and BaTiO3 fibers

Conventionally,interface effects between polymers and fillers are essential for determining the breakdown strength and energy storage density of polymer-based dielectric composites.In this study,we found that interface effects between different fillers have similar behavior.BN and Ba TiO3 fiber composite fillers with three different interface bonding strengths were successfully achieved by controlling composite processes(BT-fiber/BN<BT-fiber@BN<BT-fiber&BN),and introduced into a polyimide(PI)matrix to form composite films.Considerably enhanced breakdown strength and energy storage density were obtained in BT-fiber&BN/PI composites owing to strong interface bonding,compared to other two composite fillers,which are well supported by the data from the finite element simulation.Specifically,PI composites with only 3 wt%BT-fiber&BN possess an optimized energy storage density of approximately 4.25 J/cm^(3)at 4343 k V/cm.These results provide an effective way for adjusting and improving the energy storage properties of polymer-based composites.