Development of high-strength magnesium alloys with excellent ignition-proof performance based on the oxidation and ignition mechanisms: A review

High reactivity and ease of ignition are the major obstacles for the application of Mg alloys in aerospace.Thus,the ignition mechanisms of Mg alloys should be investigated systematically,which can guide the ignition-proof alloy design.This article concludes the factors influencing the ignition resistance of Mg alloys from oxide film and substrate microstructure,and also the mechanisms of alloying elements improving the ignition resistance.The low strength is another reason restricting the development of Mg alloys.Therefore,at the last section,Mg alloys with the combination of high strength and good ignition-proof performance are summarized,including Mg-Al-Ca based alloys,SEN(Mg-Al-Zn-Ca-Y)alloys as well as Mg-Y and Mg-Gd based alloys.Besides,the shortages and the future focus of theses alloys are also reviewed.The aim of this article is to promote the understanding of oxidation and ignition mechanisms of Mg alloys and to provide reference for the development of Mg alloys with high strength and excellent ignition-proof performance at the same time.

Historic and Future Perspectives of Storm and Cyclone

In weather sciences,the two specific terms“storm”and“cyclone”frequently appear in literature and usually refer to the violent nature of a number of weather systems characterized by central low pressure,strong winds,large precipitation amounts in the form of rain,freezing rain,or snow,as well as thunder and lightning.But what is the connection between these two specific terms?In this paper,the historic evolutions of the terms“storm”and“cyclone”are reviewed from the perspective of weather science.The earliest recorded storms in world history are also briefly introduced.Then,the origin of the term“meteorological bomb”,which is the nickname of the“explosive cyclone”is introduced.Later,the various definitions of explosive cyclones given by several researchers are discussed.Also,the climatological features of explosive cyclones,as well as the future trends of explosive cyclones under global climate change,are discussed.

基于PBL的耳鼻咽喉科学临床技能情境教学法的探索与分析

目的探索并实践耳鼻咽喉科学的临床技能学新的教学模式,以适应国家对培养更具职业精神的全面发展的卓越医师的要求。方法将具有耳鼻喉头颈外科学临床技能实验课要求的4个本科班学生随机分为实验组和对照组。实验组采用基于PBL的临床情景模拟教学方式;对照组采用传统教学模式。教学任务结束后对两组同学分别进行问卷调查和成绩考核。结果实验组学生无论是在考试成绩还是学习积极性方面都有明显提高,差异有统计学意义(P <0.05)。结论该教学方法有效地改善了教学模式,提高教学质量,符合我国对培养全能型、综合型医学人才计划的创新要求。

低铱酸性氧析出电催化剂的研究进展

开发高性能、低成本的氧析出反应(OER)电催化剂是促进质子交换膜水电解(PEMWE)制氢规模化应用的关键。迄今为止,OER催化剂的最佳选项仍为贵金属铱(Ir),但其仍存在活性不足和储量稀缺的问题,进而增加了材料成本和电力成本。因此,开发低Ir载量、高活性和稳定性间距,且能够满足PEMWE设备中大电流密度和长期运行要求的OER催化剂是十分必要的。这些目标的实现需要深入理解酸性OER机制、明晰材料设计方法,并建立可靠的性能评估指标(特别是对耐久性的评估)。综上,本文首先系统总结了目前被广泛接受的酸性OER活性表达机制(即吸附析出机制、晶格氧氧化机制和多活性中心机制)和失活机制(即活性物种溶解、晶相和形态演化、催化剂脱落和活性位点阻塞),为催化剂的微观结构设计提供指导。其次,我们讨论了最近报道的几类低铱OER催化剂,包括多金属合金氧化物、负载型催化剂、具有特殊空间结构的催化剂和单位点催化剂,并重点描述低Ir催化剂中的性能如何得以调控以及其中潜在的构效关系。随后,我们介绍了常用的催化剂稳定性评价指标、催化剂失活表征技术以及模拟PEMWE实际操作条件的催化剂寿命测试方法,希望为催化剂筛选提供依据。最后,针对未来可用于PEMWE体系的低铱OER催化剂的探索提出了一些可行建议。

α-Vitamin E derivative, RRR-α-tocopheryloxybutyric acid inhibits the proliferation of prostate cancer cells

Aim： To investigate the activity of RRR-α-tocopheryloxybutyric acid （TOB）, an ether analog of RRR-α-tocopheryl succinate （VES）, in prostate cancer cells. Methods： VES and TOB were used to treat prostate cancer LNCaP, PC3, and 22Rvl cells and primary-cultured prostate fibroblasts. The proliferation rates were determined by MTT assay, the cell viabilities were determined by trypan blue exclusion assay, and the cell deaths were evaluated by using Cell Death Detection ELISA kit. The protein expression levels were determined by Western blot analysis. Results： The MTT growth assay demonstrated that TOB could effectively suppress the proliferation of prostate cancer cells, but not normal prostate fibroblasts. Mechanism dissections revealed that TOB reduced cell viability and induced apoptosis in prostate cancer cells similar to VES. In addition, both TOB and VES suppressed prostate-specific antigen （PSA） at the transcriptional level leading to reduced PSA protein expression. Furthermore, vitamin D receptor （VDR） expression increased after the addition of TOB. Conclusion： Our data suggests that the VES derivative, TOB, is effective in inhibiting prostate cancer cell proliferation, suggesting that TOB could be used for both chemopreventive and chemotherapeutic purposes in the future.

卓越医生培养视域下“5+3”临床医学生早期接触科研项目的选题现状与思考

早期接触科研训练项目旨在培养“5+3”临床医学生综合运用所学理论、知识和技能解决实际问题的能力,选题是项目实施的第一个关键步骤。本文简要论述了安徽医科大学“5+3”临床医学生早期接触科研项目的选题现状,并结合对选题情况的调查分析,探讨选题中的关键问题,以期为提升创新型、应用型医学人才的培养质量提供依据。

ACE gene missense mutation in a case with early-onset, rapid progressing dementia

The population of early-onset Alzheimer's disease(EOAD)accounts for 1%-2%of the total population of Alzheimer's disease,and genetic mutations are more common in EOAD.The first symptom of the patient in the present case report was the decline in memories of recent events,and the disease progressed rapidly in the following 2 years.Genetic testing has revealed the presence of genetic mutations(c.A479G,p.N160S)of ACE,which causes the 160th codon of the ACE protein to change from aspartic acid to serine,and at the same time genotype of apolipoprotein E(APOE)is ε3/ε4.We think that this patient carries the mutation type of the sensitive gene ACE and the risk gene APOE of Alzheimer's disease,and this is the reason why the disease progressed rapidly.Moreover,we discussed ACE genetic mutation's meaning in EOAD progression.

Joint Acaricidal Action of Diafenthiuron and Fenbutatin-oxide Against Tetranychus cinnabarinus(Boisduval)(Acari: Tetranychidae)

[Objective]This study was conducted to obtain a new high-efficiency acaricide mixture.[Method]The synergism acaricidal of diafenthiuron and fenbutatin-oxide against carmine spider mite was investigated,and the optimal ratio of both acaricides were determined by means of co-toxicity factors and co-toxicity coefficients(CTC).[Result]At 24 h post-treatment,the LC50values of diafenthiuron and fenbutatin-oxide against T.cinnabarinus female adults were 154.67 and 93.26 mg/L,respectively,and the synergistic mass ratios of diafenthiuron and fenbutatin-oxide ranged from 1:0.06 to 1:0.87,and the optimal diafenthiuron-to-fenbutatin-oxide ratio was 1:0.39 with the LC50and CTC of 67.87 mg/L and 188.93(CTC significantly above 100 strongly indicated synergism),respectively,and the toxicity relative to diafenthiuron and fenbutatin-oxide was 2.28 and 1.37 times,respectively.[Conclusion]The joint acaricidal action of diafenthiuron and fenbutatin-oxide strongly indicates synergism.These findings proved scientific theoretical basis for mixing diafenthiuron and fenbutatin-oxide to control spider mites and developing a new synergisic acaricide.

Histiocytoid giant cellulitis-like Sweet syndrome at the site of sternal aspiration:A case report and review of literature

BACKGROUND Giant cellulitis-like Sweet syndrome(SS) is a rare subtype of SS,and reports of the combined histiocytoid type of pathology are scarce.Here,we report a case of SS with distinctive clinical presentations and which was difficult to distinguish from cellulitis.By sharing this case and a discussion of the related literature in detail,we aim to provide clinicians with new insights into the characteristics of histiocytoid giant cellulitis-like(HGC)-SS and the pathogenesis of SS.CASE SUMMARY A 52-year-old male was admitted after experiencing progressive fatigue for 1 mo and tongue swelling with pain for 1 d.He was diagnosed with myelodysplastic syndrome(MDS) and angioneurotic edema of the tongue and floor of the mouth.However,7 d after examination by sternal aspiration,a violaceous,tender,and swollen nodule developed at the site,with poorly demarcated erythema of the surrounding skin.Considering his profile of risk factors,the diagnosis of cellulitis was made and he was administered broad-spectrum antibiotics.When the lesion continued to worsen and he developed chills and fever,pathogenic and dermatopathological examination led to the diagnosis of HGC-SS.Treatment with prednisone led to the fever being relieved within 24 h and the skin lesion being resolved within 1 wk.The patient refused intensive treatment and was instead given thalidomide,erythropoietin,stanozolol,and supportive care.The prednisone was gradually tapered,with no signs of recurrence,but he died 2 mo later of severe pneumonia.CONCLUSION HGC-SS demonstrates unique manifestation.SS and leukemia cutis share cytological origin.Myelofibrosis and SS are adverse prognostic factors for MDS.

Suppressing the lattice oxygen diffusion via high-entropy oxide construction towards stabilized acidic water oxidation

The scale-up deployment of ruthenium(Ru)-based oxygen evolution reaction(OER)electrocatalysts in proton exchange membrane water electrolysis(PEMWE)is greatly restricted by the poor stability.As the lattice-oxygen-mediated mechanism(LOM)has been identified as the major contributor to the fast performance degradation,impeding lattice oxygen diffusion to inhibit lattice oxygen participation is imperative,yet remains challenging due to the lack of efficient approaches.Herein,we strategically regulate the bonding nature of Ru–O towards suppressed LOM via Ru-based high-entropy oxide(HEO)construction.The lattice disorder in HEOs is believed to increase migration energy barrier of lattice oxygen.As a result,the screened Ti_(23)Nb_(9)Hf_(13)W_(12)Ru_(43)O_(x) exhibits 11.7 times slower lattice oxygen diffusion rate,84%reduction in LOM ratio,and 29 times lifespan extension compared with the state-of-the-art RuO_(2) catalyst.Our work opens up a feasible avenue to constructing stabilized Ru-based OER catalysts towards scalable application.

Mechanical Characteristics and Mechanism of Granite Subjected to Coupling Effect of Acidic Corrosion and Freeze-Thaw Cycles

The typical climatic and environmental conditions in Central Asia are major natural factors causing local rock masses to face considerable risks of damage due to constant freeze-thaw cycles. In addition, these are exacerbated by the dense acidic environments in certain industrialized areas, such as Northern Sinkiang, China. To provide local engineering design with workable solutions, it is crucial to analyze the mechanical performance of rock masses and its mechanisms under the coupling action of corrosive acid and freeze-thaw cycles. In this study, granite samples from the northern Tien Shan Mountains near Urumchi, Xinjiang Province, as well as two kinds of sandstone samples for comparison, were subjected to different soaking conditions, including nitric acid soaking at various pH values. One or both of the freeze-thaw cycle tests and uniaxial compression test were then executed. Speculations regarding the mechanism of the performance of granite rock masses under the action of corrosive acid and freeze-thaw cycles were developed based on the results of these tests. X-ray diffraction and scanning electron microscopy were implemented to demonstrate the feasibility of the speculated mechanism. In this paper, the identification of the white crumb-like substance as SiO_(2) gel were confirmed.

Investigations for vibration and friction torque behaviors of thrust ball bearing with self-driven textured guiding surface

In order to improve the starved lubrication condition of rolling bearings,three kinds of textures,namely dimple,groove texture,and gradient groove texture,were developed on the guiding surface of thrust ball bearings in this study.The results show that gradient groove texture has the one-way self-driving function of liquid droplets.The root mean square(RMS)value of vibration acceleration of gradient groove textured bearing(GGB)decreased by 49.1% and the kurtosis decreased by 24.6% compared with non-textured bearing(NB)due to the directional spreading effect of gradient groove textures on oil.The frequency domain analysis showed that the textures mainly suppressed the medium and high-frequency energy of bearing vibration,and the GGB was reduced the most with 65.3% and 48%,respectively.In addition,whether the grease is sufficiently sheared has a large impact on the oil guiding effect,and the friction torque of GGB could decrease by 10.5% compared with NB in the sufficiently sheared condition.Therefore,the gradient groove texture with oil self-driven effect on the guiding surface of rolling bearing can effectively improve the lubrication condition of the bearing and thus reduce the bearing vibration and friction torque,which has a promising application prospect.

四川大学创办《翻译学刊》

由四川大学外国语学院主办的《翻译学刊》(Journal of Translation Studies)于2023年1月正式创刊。这是一本致力于翻译研究的专业性学术集刊,每年将出版两集。四川大学的历史悠久,巴金、吕叔湘、卞之琳、吴宓等著名学者曾在该校任教或求学,他们之中的多数也是翻译家。该刊的创办是对这一文脉的传承与发展。

Combined effect of the use of carbon fiber and seawater and the molecular structure on the tribological behavior of polymer materials

The combined effect of the use of carbon fiber and seawater and the molecular structure on the tribological behavior of various polymer materials under natural seawater lubrication was investigated. After the investigation, the wear morphology of the contact surface was observed by a laser scanning confocal microscope, and the texture of the wear scars and tracks were presented in 3 D profiles. Moreover, the mechanism of mixed lubrication and wear resistance was analyzed. The results demonstrated that the friction coefficient of carbon fiber-reinforced polyetheretherketone(CFRPEEK) is the lowest and fluctuates at approximately 0.11. Moreover, the seven polymer materials in ascending order of friction coefficients are CFRPEEK, carbon fiber-reinforced polyamide-imide, polytetrafluoroethylene, polyoxymethylene, polyetheretherketone(PEEK), acrylonitrile butadiene styrene resin, and glass fiber–epoxy resin. More critically, the simultaneous incorporation of deposition, polymeric scrap, hydrophilic groups, and seawater resulted in a decrease in the friction and wear of polymer materials under seawater lubrication. This observation implies that a synergistic friction-reducing and wear-resistant effect exists between carbon fiber, seawater, and the molecular structure of PEEK. As a result, a highly effective polymer material was discovered, CFRPEEK, which has the lowest friction coefficient of 0.11 and lowest wear rate of 2 × 10^(–5) mm^3?(N?m)^(-1) among the polymer materials; this validates the selection of dual friction pairs for seawater hydraulic components.

Assessment of water-based cutting fluids with green additives in broaching

In order to improve the cutting performance in broaching,the lubrication and cleaning effects offered by water-based cutting fluids with green additives need to be studied from the viewpoint of green manufacturing.Therefore,water-based solutions with castor oil,surfactant(linear alkylbenzene sulfonate,LAS),and nanographite were prepared by ultrasonic agitation and sprayed into the zone of broaching via atomization.The performances of the cutting fluids,in terms of the viscosity,specific heat,wetting angle,and droplet size,were evaluated to discuss their effects on the broaching load.Among the fluids,the addition of LAS into oil-in-water(WO-S),where its cutting fluid with 10 wt.%castor oil and 1.5 wt.%surfactant,exhibited the lowest broaching force.With regard to the lubricating and cleaning mechanisms,WO-S has good wettability and permeability,and hence,can lubricate the cutting edge of the tool to decrease the cutting load,cool the cutting edge to keep it sturdy,and clean the surface of the cutting edge to keep it sharp.The results reveal that the simultaneous addition of castor oil and LAS had remarkable effects on the lubrication and cleaning,and resulted in a broaching load reduction of more than 10%compared to commercial cutting fluids.However,the addition of nanographite could not improve the lubrication owing to its agglomeration.

Penetration and lubrication evaluation of vegetable oil with nanographite particles for broaching process

With increasing environmental concerns,the substitution of mineral oil-based cutting fluid has become an urgent issue.Using vegetable soybean oil as base fluid,nanofluid cutting fluids(NFCFs)were prepared by adding different weight concentrations of nanographite particles(NGPs),and their penetration and lubrication performances were studied.A novel simulated tool-chip slit with micrometersized geometry was manufactured to evaluate and quantify the penetration rate of the NFCFs by image analysis approach.Moreover,a large number of comparative experiments on the closed-type broaching machine were carried out to compare the performance of the proposed NFCFs and a commercial cutting fluid in terms of cutting force,workpiece surface roughness,and metal chip.It is found that there is an optimal NGP concentration in NFCF for practical cutting applications.When the concentration of NGP is 0.4 wt%,the broaching process lubrication exhibits an ideal mixed lubricate state,resulting in minimal friction resistance,and thus,both the cutting force and chip curling angle reach their corresponding best values.Moreover,the proposed NGP-based vegetable-oil cutting fluid exhibits excellent environmentfriendliness and low-cost consumption in the minimal quantity lubrication(MQL)method;this demonstrates its potential for replacing the traditional broaching cutting fluid.

Serostatus disclosure and associated factors among people living with HIV/AIDS (PLWHA) in Liuzhou City, China

Introduction HIV serostatus disclosure has become an entry criterion for prevention of sexual partners spread, so we aimed to examine the prevalence of disclosure and associated factors among people living with HIV / AIDS( PLWHA) in Liuzhou City,Guangxi Zhuang Autonomous Region,southern China. Methods The PLWHA with marital or regular sexual relationship were eligible for our study,and a self-designed questionnaire was assigned to all the conveniently sampled participants. Determinants of disclosure were analyzed using chi-square test and binary Logistic regression. Results A total of 425 PLWHA were included in the present study. Two hundred and forty-five( 57. 6%) disclosed their HIV-positive status to their spouses / regular sexual partners,while 180( 42. 4%) did not. Among the 245 informed spouses / regular sexual partners,236( 96. 3%) had received the HIV testing and the positive rate was 50. 4%. While among the non-in-formed spouses / regular sexual partners,63( 35. 0%) had received the HIV testing and the positive rate was 3. 2%. Binary Logistic regression analysis indicated that age,area,monthly income,HIV / AIDS related knowledge and antiretroviral therapy( ART) were independently associated with HIV serostatus disclosure. Conclusions The disclosure rate was low in this study. As to its influencing factors,it is necessary to provide comprehensive disclosure consulting among PLWHA living in urban,the elderly or high monthly income and emphasize the propaganda on HIV / AIDS related knowledge,expand coverage for antiretroviral therapy, so as to provide scientific reference for promoting HIV disclosure and reducing the HIV incidence of spouses / regular sexual partners among PLWHA.

Stimuli responsive co-delivery of celecoxib and BMP2 from micro-scaffold for periodontal disease treatment

Controlling inflammation meanwhile facilitating tissue regeneration has been considered as a promising strategy to treat inflammatory bone defect. Herein, we describe the synthesis of a bio-sensitive poly(lactic-co-glycolic acid)/mesoporous silica nanocarriers core-shell porous microsphere(PLGA/MSNsPMS) encapsulated poly(L-lactic acid)(PLLA) spongy nanofibrous micro-scaffold as a new generation of therapeutic platform for effective reconstruction of bone defects caused by periodontal diseases.The PLGA/MSNs-PMS were designed as stimuli-responsive carriers for on-demand co-delivery of multiple biomolecules to provide proper physiological environment, while the multi-level(from macro-,micro-to nanometers) nanofibrous and porous structures in PLLA micro-scaffold were in charge of the reconstruction of ECM, which synergistically contribute to the enhancement of new tissue formation under inflammatory condition. After local injection into periodontal tissue, this construct could sequentially release bone growth factor(BMP-2) as well as anti-inflammatory drug(celecoxib) loaded MSNs in response to the over-expressed matrix metalloproteinases(MMP) in periodontal region. During alveolar bone regeneration induced by BMP-2 and ECM like structure, the MSNs would further deliver celecoxib in target cells to achieve inflammation inhibition, resulting in effective treatment of periodontal disease.

Bacteria-assisted delivery and oxygen production of nano-enzyme for potent radioimmunotherapy of cancer

Tumor-targeting attenuated Salmonella could induce certain antitumor therapeutic effect through its proliferation characteristic and the consequent activated immune response,while host defense cells represented by neutrophils would trap and eliminate these invading bacteria via producing excess hydrogen peroxide(H_(2)O_(2))-including reactive oxygen species in the bacteriainfected tumor,thereby impairing the efficacy of the bacteria treatment of tumor.Herein,we attempt to combine bacteria treatment and oxygen-dependent radioimmunotherapy of tumor through injection of neutrophil-targeted nano-catalase into the bacteria-treated mice for perfect tumor treatment outcome.Denatured albumin is used to coat catalase and deliver it to the neutrophils infiltrated in bacteria-infected tumor tissue.Taking advantage of the generating H_(2)O_(2)by neutrophils,easily-diffused oxygen is produced and spread the whole tumor under the catalysis of nano-enzyme,leading to enhanced radiotherapy of hypoxic tumor cells.Moreover,the optimized tumor microenvironment,synergistically caused by potent immune-stimulation of bacteria,generating oxygen and tumor radiotherapy,would boost the antitumor immunity.This novel combination therapy strategy holds great promise to provide new ideas for future clinical cancer treatment.

世界读书日

1995年,联合国教科文组织宣布4月23日为“世界读书日”。其设立的目的是推动更多的人去从事阅读和写作,希望所有人都能尊重和感谢为人类文明做过巨大贡献的文学家、文化学者、科学家和思想大师们,并希望促进保护知识产权。每年这一天,世界各国都会举办各种各样的读书宣传活动。疫情时代,人们更倾向于关注自己,关注现实话题,希望通过阅读缓解心理压力,也希望能从书籍中找到解决自身困境的答案。