基于问题导向的物理化学实验项目设计与改进——以液体表面张力测定为例

以日常生活现象(洗衣时的白色絮凝物)为切入点,通过问题导向,引导学生自主设计实验。将表面张力的测量融入探究生活现象背后化学原理的过程中,综合运用多种技术手段,建立“发现问题-探索实践-回归课本”的探索型实验模式,从而巩固学生对胶体与界面化学知识点的理解。改进后的实验内容更丰富,挑战度更高,综合性更强,趣味性更浓,有利于培养学生分析和解决问题的能力,能更好地培养学生的探究性思维。此外,本实验安全性较高,易于操作,对设备无特殊要求,非常适合本科教学实验。

Prostate cancer with elevated free prostate-specific antigen density:A case report

BACKGROUND Prostate cancer is the second most common cancer among men worldwide,and prostate-specific antigen(PSA)is often used in clinical practice to screen for prostate cancer.Normal total PSA(tPSA)level initially excludes prostate cancer.Here,we report a case of prostate cancer with elevated free PSA density(fPSAD).CASE SUMMARY A patient diagnosed with benign prostatic hyperplasia underwent prostatectomy,and the postoperative pathological results showed acinar adenocarcinoma of the prostate.The patient is currently undergoing endocrine chemotherapy.CONCLUSION We provide a clinical reference for diagnosis and treatment of patients with normal tPSA but elevated fPSAD.

IL-33/ST2信号通路在缺血性脑卒中的作用

缺血性脑卒中是临床上常见的脑血管疾病,免疫炎症反应在其发病机制中起着关键作用。IL-1家族新成员IL-33是Th2型免疫反应的关键活化分子,经由IL-33/ST2信号通路在不同的疾病和模型中发挥促炎或抑炎效应。近年来,关于IL-33及其信号通路在缺血性脑卒中发生、发展中的作用和作用机制的研究越来越得到关注,被认为是缓解缺血性脑损伤后炎症反应的新型靶点。本文综述IL-33/ST2信号通路的生成及其在缺血性脑卒中的病理生理作用,并介绍最新的相关研究进展。

Sodium selenite promotes neurological function recovery after spinal cord injury by inhibiting ferroptosis

Ferroptosis is a recently discovered form of iron-dependent cell death,which occurs during the pathological process of various central nervous system diseases or injuries,including secondary spinal cord injury.Selenium has been shown to promote neurological function recovery after cerebral hemorrhage by inhibiting ferroptosis.However,whether selenium can promote neurological function recovery after spinal cord injury as well as the underlying mechanism remain poorly understood.In this study,we injected sodium selenite(3μL,2.5μM)into the injury site of a rat model of T10 vertebral contusion injury 10 minutes after spinal cord injury modeling.We found that sodium selenite treatment greatly decreased iron concentration and levels of the lipid peroxidation products malondialdehyde and 4-hydroxynonenal.Furthermore,sodium selenite increased the protein and mRNA expression of specificity protein 1 and glutathione peroxidase 4,promoted the survival of neurons and oligodendrocytes,inhibited the proliferation of astrocytes,and promoted the recovery of locomotive function of rats with spinal cord injury.These findings suggest that sodium selenite can improve the locomotive function of rats with spinal cord injury possibly through the inhibition of ferroptosis via the specificity protein 1/glutathione peroxidase 4 pathway.

The circular RNA Rap1b promotes Hoxa5 transcription by recruiting Kat7 and leading to increased Fam3a expression,which inhibits neuronal apoptosis in acute ischemic stroke

Circular RNAs can regulate the development and progression of ischemic cerebral disease.However,it remains unclear whether they play a role in acute ischemic stroke.To investigate the role of the circular RNA Rap1b(circRap1b)in acute ischemic stroke,in this study we established an in vitro model of acute ischemia and hypoxia by subjecting HT22 cells to oxygen and glucose deprivation and a mouse model of acute ischemia and hypoxia by occluding the right carotid artery.We found that circRap1b expression was remarkably down-regulated in the hippocampal tissue of the mouse model and in the HT22 cell model.In addition,Hoxa5 expression was strongly up-regulated in response to circRap1b overexpression.Hoxa5 expression was low in the hippocampus of a mouse model of acute ischemia and in HT22-AIS cells,and inhibited HT22-AIS cell apoptosis.Importantly,we found that circRap1b promoted Hoxa5 transcription by recruiting the acetyltransferase Kat7 to induce H3K14ac modification in the Hoxa5 promoter region.Hoxa5 regulated neuronal apoptosis by activating transcription of Fam3a,a neuronal apoptosis-related protein.These results suggest that circRap1b regulates Hoxa5 transcription and expression,and subsequently Fam3a expression,ultimately inhibiting cell apoptosis.Lastly,we explored the potential clinical relevance of circRap1b and Hoxa5 in vivo.Taken together,these findings demonstrate the mechanism by which circRap1b inhibits neuronal apoptosis in acute ischemic stroke.

凹坑对风力机翼型气动性能的影响

叶片是风力机的主要部件,叶片上的损失也是风力机主要损失来源之一,因此减少叶片损失,提高风力机性能一直是人们研究的课题。文中借助fluent软件对NACA 4412叶片进行数值模拟,计算采用SST k-ω湍流模型,分析了Re=6.8×10^(5)时翼型上的流场分布,并将得到的升力系数和阻力系数与实验数据进行了比较,证明了文中算法的可靠性。文中通过对改变凹坑半径大小、位置等方式进行研究,观察其对风力机气动性能的影响。研究结果表明,将凹坑布置在叶片尾缘附近分离涡相对于原型更小,随着凹坑半径的增加,减小流动分离的效果先增加后减小,在半径为10mm时控制效果最好。攻角大于25°时,将半径为10mm的凹坑布置在60%~82%弦长处,可使升力系数增加6.9%。

附面层抽吸孔对扇形扩压叶栅分离流动控制效果研究

为探究附面层抽吸对跨声速扇形扩压叶栅分离流动控制、气动性能和流场结构的影响,本文基于CFX数值模拟方法对扇形扩压叶栅进行端壁孔抽吸方案研究,并分析叶栅抽吸效果随抽吸流量的变化规律。抽吸位置分布在上下端壁近吸力面端壁处,将弦长四等分为四个不同方案。对比原型及各抽吸孔方案可以得到,当抽吸流量为原型叶栅进口质量流量的0.7%时,最优方案为分离点下游附近的抽吸方案,下端壁单侧抽吸时扇形叶栅总压损失较原型叶栅降低7.83%,静压较原型提高7.86%。同时随着抽吸流量的增加,叶栅流动损失逐渐降低,扩压能力提升。

Detection and analysis of the volatile components in the essential oils of Chrysanthemum and Opisthopappus species and their hybrid progeny

Chrysanthemum and Opisthopappus are genera that include perennial herbaceous floral species,including excellent varieties with strong fragrances resulting from long-term artificial selection.Thus,they are ornamentally and economically important flower resources.In this study,a water distillation method was used to extract essential oils from the inflorescences of Chrysanthemum and Opisthopappus wild resources and hybrid progeny with high essential oil contents(Chrysanthemum morifolium'xiangjin',C.morifolium'xiangyun',C.morifolium'xinjiboju',Opisthopappus taihangensis,Opisthopappus longilobus,Chrysanthemum lavandulifolium,and C.morifolium'minghuangju').The essential oil extraction rates were as follows:1.17‰,2‰,1.67‰,2.17‰,0.43‰,1‰,and 1.17‰.On the basis of HS-SPME-GC-MS(Headspace solid phase microextraction-gas chromatography-mass spectrometry),225 volatile compounds were detected in the seven analyzed essential oil samples.Each essential oil had a relative volatile component content exceeding 0.3.The three most abundant compounds were olefins(46 types),alcohols(34 types),and esters(18 types).The volatile components with relatively high contents included thymol,D-camphor,pinene,eucalyptol,2-terpineol,terpineol,trans-caryophyllene,andβ-elemene.These volatile compounds have strong biological activities and are useful components of medicines and daily-use products.An evaluation of their antibacterial effects demonstrated that the essential oils of C.'xiangjin',C.'xiangyun',C.'xinjiboju',O.taihangensis,O.longilobus,and C.'minghuangju'inhibited the growth of Escherichia coli.The C.lavandulifolium essential oil inhibited the growth of Pectobacterium carotovorum.The results of this study will provide researchers with an important theoretical basis for the development and application of Chrysanthemum and Opisthopappus essential oils.

灾害事故现场批量伤员现代智能检伤分类管理系统应用

重大灾害事故中需要快速对大量灾害伤员的数量、严重性进行或将优先处理的伤员进行分类,以发挥最优化使用急救资源。检伤分类是紧急医疗救援中一个非常重要的环节。其主要目的是根据患者的伤情严重程度,将他们分成不同的优先等级,以便进行紧急治疗。传统的人工检伤分类方法存在效率低下、误判率高等问题,无法满足大规模灾害事故的需求。因此,应用现代智能检伤分类管理系统成为迫切需要。随着科技水平的提高以及对检伤分类的重视,开始对检伤分类相关装置系统进行设计和研发。目前我国关于现代化检伤分类管理系统的研究能够快速记录并整合伤员的检伤信息。笔者主要介绍检伤分类管理系统并总结出不同系统的优缺点和新系统开发的启示以及如何才能推广检伤分类系统的使用,为未来新系统开发和推广提供参考和借鉴。

Self-assembly multifunctional DNA tetrahedron for efficient elimination of antibiotic-resistant bacteria

Antibiotic resistance is a major challenge in the clinical treatment of bacterial infectious diseases.Herein,we constructed a multifunctional DNA nanoplatform as a versatile carrier for bacteria-specific delivery of clinical antibiotic ciprofloxacin(CIP)and classic nanoantibiotic silver nanoparticles(AgNP).In our rational design,CIP was efficiently loaded in the self-assembly double-bundle DNA tetrahedron through intercalation with DNA duplex,and single-strand DNA-modified AgNP was embedded in the cavity of the DNA tetrahedron through hybridization.With the site-specific assembly of targeting aptamer in the well-defined DNA tetrahedron,the bacteria-specific dual-antibiotic delivery system exhibited excellent combined bactericidal properties.With enhanced antibiotic accumulation through breaking the out membrane of bacteria,the antibiotic delivery system effectively inhibited biofilm formation and promoted the healing of infected wounds in vivo.This DNAbased antibiotic delivery system provides a promising strategy for the treatment of antibiotic-resistant infections.

Effect of Ag on High-Temperature Oxidation Behavior of Mg-6.5Gd-5.6Y-0.1Nd-0.01Ce-0.4Zr Alloy

In this paper,the isothermal oxidation experiments were used to study the effect of Ag on the high-temperature oxidation behavior of Mg-6.5Gd-5.6Y-0.1Nd-0.01Ce-0.4Zr(wt%)alloy oxidized at 350℃,400℃ and 450℃ for 120 h.The results show that the oxidation weight gain of the alloy mainly occurs in the early oxidation stage(0-20 h).This reason attributes to the lack of protective oxide film and the rapid inward diffusion of oxygen through the macroscopic defects of the incomplete oxide film.When dense oxide films such as Y_(2)O_(3),Gd_(2)O_(3),and ZrO2 form,they hinder the inward transport of oxygen ions and improve the high-temperature oxidation resistance of the alloy.In addition,the role of the Ag element at three temperatures is different.The addition of Ag mainly promotes the formation of eutectic phases such as Mg3Gd,Mg24Y5,and Ag2Gd,which reduces the content of Gd and Y elements in the alloy matrix,resulting in a decrease in the diffusion rate of Gd and Y elements during the oxidation process at 350℃ and 400℃,and weakens the oxidation resistance of Ag-containing alloys.However,in the oxidation experiment at 450℃,a large amount of eutectic phase is solid dissolved into the matrix,reducing the difference in element content.At this time,it is detected that the Ag element promoted the outward diffusion of Gd and Y elements,accelerating the formation of the oxide film.The oxidation resistance of Ag-containing alloys is improved.

MiR319-targeted OsTCP21 and OsGAmyb regulate tillering and grain yield in rice

Multiple genes and microRNAs(miRNAs)improve grain yield by promoting tillering.MiR319s are known to regulate several aspects of plant development;however,whether miR319s are essential for tillering regulation remains unclear.Here,we report that miR319 is highly expressed in the basal part of rice plant at different development stages.The miR319 knockdown line Short Tandem Target Mimic 319(STTM319)showed higher tiller bud length in seedlings under low nitrogen(N)condition and higher tiller bud number under high N condition compared with the miR319a-overexpression line.Through targets prediction,we identified OsTCP21 and OsGAmyb as downstream targets of miR319.Moreover,OsTCP21 and OsGAmyb overexpression lines and STTM319 had increased tiller bud length and biomass,whereas both were decreased in OsTCP21 and OsGAmyb knockout lines and OE319a.These data suggest that miR319 regulates rice tiller bud development and tillering through targeting OsTCP21 and OsGAmyb.Notably,the tiller number and grain yield increased in STTM319 and overexpression lines of OsTCP21 and OsGAmyb but decreased in OE319a and knockout lines of OsTCP21 and OsGAmyb.Taken together,our findings indicate that miR319s negatively affect tiller number and grain yield by targeting OsTCP21 and OsGAmyb,revealing a novel function for miR319 in rice.

In situ TEM visualization of Ag catalysis in Li-O_(2)nanobatteries

Lithium-oxygen(Li-O_(2))batteries have been considered as an ideal solution to solving the global energy crisis.Silver(Ag)and Agbased catalyst have been extensively studied due to their high catalytic activities in Li-O_(2)batteries.However,it remains a challenge to track the catalytic mechanism during the charge/discharge process.Here,a nanoscale processing method was used to assemble a Li-O_(2)nanobattery in an aberration-corrected environmental transmission electron microscope(ETEM),where a single Ag nanowire(NW)was used as catalyst for O_(2)electrode.A visualization of the lithium ion insertion process during the electrochemical reactions was achieved in this nanobattery.Numerous Ag nanoparticles(NPs)were observed on the surface of the Ag NW,which were covered by the discharge product Li2O_(2).By simultaneously studying the evolution of the interface and the phase transformation,it can be concluded that these Ag NPs wrapped around Ag NW acted as catalyst during the subsequent charge/discharge reaction.Based on these studies,Ag NPs decorated on porous carbon were synthesized,it can simultaneously improve the cycling stability(100 cycles)and the maximum specific capacity(17,371 mAh·g^(−1)at a current density of 100 mA·g^(−1))in a coin cell Li-O_(2)battery.This study suggests that nanoscale Ag may be a promising catalyst for Li-O_(2)battery.

20(S)-Protopanaxatriol promotes the binding of P53 and DNA to regulate the antitumor network via multiomic analysis

Although the tumor suppressor P53 is known to regulate a broad network of signaling pathways,it is still unclear how certain drugs influence these P53 signaling netw orks.Here,we used a comprehensive singlecell multiomics view of the effects of ginsenosides on cancer cells.Transcriptome and proteome profiling revealed that the antitumor activity of ginsenosides is closely as sociated with P53 protein.A miRNA-proteome interaction network revealed that P53 controlled the transcription of at least 38 proteins,and proteomemetabolome profiling analysis revealed that P53 regulated proteins involved in nucleotide metabolism,amino acid metabolism and"Warburg effect".The results of integrative multiomics analysis revealed P53 protein as a potential key target that influences the anti-tumor activity of ginsenosides.Furthermore,by applying affinity mass spectrometry(MS)screening and surface plasmon resonance fragment library screening,we confirmed that 20(S)-protopanaxatriol directly targeted adj acent regions of the P53 DNA-binding pocket and promoted the stability of P53-DNA interactions,which further induced a series of omics changes.

Simultaneous Determination of Eleven Bioactive Constituents in Honey-Processed Licorice by High-Performance Liquid Chromatography-Diode Array Detector and Its Application from the Perspective of Processing Influence under Orthogonal Design

Objective:The aim of this study was to develop a reliable approach to simultaneously quantify 11 markers and explore the quality variation in honey-processed licorice.Materials and Methods:A high-performance liquid chromatography-diode array detector method was developed for the simultaneous determination of 11 markers(nine flavonoids and two triterpenoid saponins)in honey-processed licorice.The changes to the 11 markers in honey-processed licorice were investigated using an orthogonal design with three input factors.Results:The established method was precise,accurate,and sensitive enough for the simultaneous quantitative evaluation of 11 markers in honey-processed licorice.Intuitive analysis and variance analysis revealed that(1)the soaking time of crude licorice,stir-frying temperature,and stir-frying time remarkably influenced the content of liquiritin apioside,signifying the decomposition of liquiritin apioside to liquiritin or transformation of liquiritin apioside to isoliquiritin apioside,(2)stir-frying temperature significantly influenced licorice-saponin G2,(3)stir-frying temperature was the most important factor of the three input factors,(4)in terms of composition,honey fried licorice had significant effects on two components,namely liquiritin apioside and licorice-saponin G2.Conclusions:Honey processing influenced the content of the 11 licorice analytes differently.This paper highlights the first report on how the quality of honey-processed licorice varies under different processing conditions and suggests the optimal levels of the investigated three factors as A2B2C3 according to the degrees of influence of these factors on the 11 components.Specifically,the soaking time of crude licorice with honey solution,stir-frying temperature,and stir-frying time were 40 min,100°C,and 20 min,respectively.

Blockchain: A new safeguard for agri-foods

Blockchain implementation in agriculture has begun.Blockchain is recognized as an emerging technology in the agri-foods industry which may provide an efficient and robust mechanism for enhancing food traceability and a transparent and reliable way to validate quality,safety,and sustainability,of agri-foods.However,the technology is in its nascency,therefore,this review was written to foster discussion and encourage the application of blockchain technology,especially in the agri-food industry.In this review,the working principle of blockchain for data recording and tracking is briefly described.The collaborationmodels for the current blockchain applications on agri-foods are summarized.Furthermore,the specific utilization of blockchain to enhance safety and quality of agri-foods is discussed in four aspects:enhance the data transparency,realize data traceability,improve the food safety and quality monitoring,and reduce the cost of financial transactions.A case study on aWalmart pork traceability system has been provided to demonstrate how blockchain may be used to enhance the food traceability.Finally,challenges and future trends of blockchain technology in agri-foods concerning data/cost management,data security,and data integration are discussed.Blockchain technology reveals a promising approach to foster a future of agri-foods system in a way that is safer,healthier,more sustainable,and reliable.

Preparation of chitosan/ alginate microcapsules by high-voltage electrostatic method

Chitosan and sodium alginate have the opposite charges;they can become a gelatin by the electrostatic attraction,High-voltage electrostatic droplet generator method was used to prepare chitosan-sodium alginate microcapsule.Multi-layer chitosan-sodium alginate microcapsule was prepared through layer-by-layer self-assembly,and the morphology was investigated.In addition,the release property of ofloxacin in microcapsules was studied by UV-Vis microscopy under different conditions such as pH value,layer number,etc.The results showed that the prepared microcapsules have a smooth surface with average particle size about 100μm.The result of controlled release indicated that the prepared microcapsules are pH-independent,and the rate of release decreased when the layer number increases.