Meso-mechanical anisotropy and fracture evolution of reef limestones from the Maldives Islands and the South China Sea

Reef limestone is a biogenic sedimentary rock widely distributed in coral reef areas, acting as an important foundation for coast construction. Due to its special biogenic origin, reef limestone is different from conventional rocks both in terms of rock structure and mechanical properties. In this study, mesoscale uniaxial compression experiments with five different loading directions were conducted on two kinds of reef limestones from the Maldives Islands and the South China Sea, respectively. The real-time high-resolution videos and images of failure processes were recorded simultaneously to investigate the fracture evolution and fracture surface roughness of reef limestones. It demonstrated that the reef limestones belonged to extremely soft to soft rocks, and their uniaxial compressive strength (UCS) values fluctuated with high discreteness. The mesoscale mechanical properties of reef limestones were highly anisotropic and mainly controlled by pore structure. The occurrence of dissolution pores in reef limestone tended to intensify mechanical anisotropy. With the integration of the fracture initiation and propagation features of reef limestones, it is supposed that the intrinsic mechanism of anisotropy was probably attributed to the differences in coral growth direction and dissolution. Furthermore, the quantified fracture surface roughness was revealed to have a good consistency with density and UCS for the reef limestones from the South China Sea. The findings are helpful for providing theoretical and experimental references for engineering construction in coral reef areas.

Extracorporeal membrane oxygenation versus cardiopulmonary bypass during transcatheter aortic valve implantation: a meta-analysis of survival benefits

Since its approval by the Food and Drug Administration in 2011,transcatheter aortic valve implantation(TAVI)has rapidly evolved to become the preferred ultimate intervention for high-and intermediate-risk patients with severe symptomatic aortic stenosis.[1]This is due to its non-open-heart,minimally invasive and off-pump advantages.[1]Nevertheless,as a result of the frequent frailty and comorbidity profiles of patients undergoing TAVI,such as advanced cardiac dysfunction and extensive coronary artery disease,or technically difficult anatomy for the procedure itself,[2-4]it is common for these patients to experience critical circulatory collapse perioperatively.These factors are linked to elevated mortality rates,necessitating suitable mechanical circulatory support(MCS)to reverse the disastrous situations.[5]

Unveiling controls of the latitudinal gradient of surface pCO_(2) in the Kuroshio Extension and its recirculation regions(northwestern North Pacific)in late spring

In the northwestern North Pacific,annual net air-sea CO_(2) flux is greatest in the Kuroshio Extension(KE)zone,owing to its low annual mean partial pressure of CO_(2)(pCO_(2)),and it decreases southward across the basin.To quantify the influences of factors controlling the latitudinal gradient in CO_(2) uptake,sea surface pCO_(2) and related parameters were investigated in late spring of 2018 in a study spanning the KE,Kuroshio Recirculation(KR),and subtropical zones.We found that the sea-to-air pCO_(2) difference(ΔpCO_(2))was negative and at its lowest in the KE zone.ΔpCO_(2) gradually increased southward across the KR zone,and the sea surface was nearly in air-equilibrium with atmospheric CO_(2) in the subtropical zone.We found that northward cooling and vertical mixing were the two major processes governing the latitudinal gradient in surface pCO_(2) and ΔpCO_(2),while biological influences were relatively minor.In the KE zone affected by upwelling,the vertical-mixing-induced increase in surface pCO_(2) likely canceled out approximately 61%of the decrease in surface pCO_(2) caused by cooling and biological activities.Moreover,the prolonged air-sea equilibration for CO_(2) and relatively short hydraulic retention time jointly led to the low surface pCO_(2) in the KE zone in spring.Ultimately,the cooling KE current flows out of the region before it can be re-equilibrated with atmospheric CO_(2).

Recent research process on perovskite photodetectors:A review for photodetector——materials,physics,and applications

The perovskite photodetectors can be used for image sensing, environmental monitoring, optical communication, and chemical/biological detection. In the recent five years, the perovskite photoelectric detectors with various devices are welldesigned and have made unprecedented progress of light detection. It is necessary to emphasize the most interesting works and summarize them to provide researchers with systematic information. In this review, we report the recent progress in perovskite photodetectors, including highly sensitive, ultrafast response speed, high gain, low noise, flexibility, and narrowband, concentrating on the photodetection performance of versatile halide perovskites(organic–inorganic hybrid and all inorganic compositions). Currently, organic–inorganic hybrid and all-inorganic halide microcrystals with polycrystalline film, nanoparticle/wire/chip, and block monocrystalline morphology control show important performance in response rate,decomposition rate, noise equivalent power, linear dynamic range, and response speed. It is expected that a comprehensive compendium of the research status of perovskite photodetectors will contribute to the development of this area.

Evidence of vapor shielding effect on heat flux loaded on flowing liquid lithium limiter in EAST

A lithium(Li)vapour layer was formed around a flowing liquid Li limiter to shield against the plasma incident power and reduce limiter heat flux in the EAST tokamak.The results revealed that after a plasma operation of a few seconds,the layer became clear,which indicated a strong Li emission with a decrease in the limiter surface temperature.This emission resulted in a dense vapour around the limiter,and Li ions moved along the magnetic fleld to form a green shielding layer on the limiter.The plasma heat flux loaded on the limiter,measured by the probe installed on the limiter,was approximately 52%lower than that detected by a fast-reciprocating probe at the same radial position without the limiter in EAST.Additionally,approximately 42%of the parallel heat flux was dissipated directly with the enhanced Li radiation in the discharge with the liquid metal infused trenches(LIMIT)limiter.This observation revealed that the Li vapour layer exhibited an excellent shielding effect to liquid Li on plasma heat flux,which is a possible beneflt of liquid-plasma-facing components in future fusion devices.

Research on Real-Time High Reliable Network File Distribution Technology

The rapid development of Internet of Things(IoT)technology has made previously unavailable data available,and applications can take advantage of device data for people to visualize,explore,and build complex analyses.As the size of the network and the number of network users continue to increase,network requests tend to aggregate on a small number of network resources,which results in uneven load on network requests.Real-time,highly reliable network file distribution technology is of great importance in the Internet of Things.This paper studies real-time and highly reliable file distribution technology for large-scale networks.In response to this topic,this paper studies the current file distribution technology,proposes a file distribution model,and proposes a corresponding load balancing method based on the file distribution model.Experiments show that the system has achieved real-time and high reliability of network transmission.

Clinical Observation of 48 Cases of Black Eye Circle Treated with Modified Yu Rong San Gel Eye Mask

Objective:To observe the clinical effect of modified Yu Rong San gel eye mask in the treatment of dark circles.Methods:96 cases of patients with dark circles were randomly divided into treatment group and control group.In the control group and the treatment group,the common eye mask and the modified Yu Rong San gel eye mask were applied to the black circle area respectively.After 15min,water was used to wash the face,the application of the mask for one time a day,four weeks,one course,and three courses were observed.Results:After three courses of treatment,the total effective rate of the treatment group was higher than that of the control group(P<0.05);the area of black eye circles in the treatment group was smaller than that before treatment(P<0.05);compared with the control group,the score of black eye circles was lower than that before treatment,the difference was statistically significant(P<0.05).Conclusions Addition and reduction of Yu Rong San gel eye mask is effective in the treatment of dark circles.

Bacterial and cancerous cell membrane fused liposome coordinates with PD-L1 inhibitor for cancer immunotherapy

Although tumor cell membranes with broad-spectrum antigens have been explored for cancer vaccines for decades,their relatively poor capacity to stimulate immune responses,especially cellular immune responses,has limited their application.Here,we presented a novel bacterial and cancerous cell membrane fusogenic liposome for co-delivering cell membrane-derived antigens and adjuvants.Meanwhile,a programmed death-ligand 1(PD-L1)inhibitor,JQ-1,was incorporated into the formulation to tackle the up-regulated PD-L1 expression of antigen-presenting cells(APCs)upon vaccination,thereby augmenting its anti-tumor efficacy.The fusogenic liposomes demonstrated significantly improved cellular uptake by APCs and effectively suppressed PD-L1 expression in bone marrow-derived dendritic cells(BMDCs)in vitro.Following subcutaneous vaccination,the nano-vaccines efficiently drained to the tumor-draining lymph nodes(TDLNs),and significantly inhibited PD-L1 expression of both dendritic cells(DCs)and macrophages within the TDLNs and tumors.As a result,the liposomal vaccine induced robust innate and cellular immune responses and inhibited tumor growth in a colorectal carcinoma-burden mouse model.In summary,the fabricated cell membrane-based fusogenic liposomes offer a safe,effective,and easily applicable strategy for tumor immunotherapy and hold potential for personalized cancer immunotherapy.

弥漫大B细胞淋巴瘤治疗后血清β2-MG VEGF与LDH水平变化及其临床意义

目的:分析弥漫大B细胞淋巴瘤(diffuse large B-cell lymphoma,DLBCL)患者治疗后血清β2微球蛋白(β2 microglobulin,β2-MG)、血管内皮生长因子(vascular endothelial growth factor,VEGF)及乳酸脱氢酶(lactate dehydrogenase,LDH)水平的变化和临床意义。方法:选取2015年2月至2017年7月四川省人民医院收治的89例DLBCL患者为研究对象(DLBCL组),选择同期至四川省人民医院行体格检查的健康人群40例作为对照组,入院后所有DLBCL患者均接受标准化疗,化疗前后均留取患者外周静脉血,测定血清β2-MG、VEGF及LDH水平的变化,与对照组相比;采集所有DLBCL患者的临床病例资料,分析上述因子的变化与DLBCL患者临床病理参数和疗效的关系。结果:入院时DLBCL患者血清β2-MG、VEGF及LDH水平均高于对照组(P<0.05);化疗后DLBCL患者血清β2-MG、VEGF及LDH水平均降低,与同组化疗前比较差异具有统计学意义(P<0.05);化疗R-CHOP方案组患者的治疗有效率明显高于CHOP组(P<0.05);伴典型B症状患者血清LDH水平高于未伴B症状患者(P<0.05),Ann Arbor分期为Ⅲ～Ⅳ期患者血清β2-MG、VEGF及LDH水平均高于分期为Ⅰ～Ⅱ期患者(P<0.05),伴骨髓侵犯患者高于未伴骨髓侵犯患者(P<0.05),国际预后指数(international prognostic index,IPI)为高危的患者高于低危患者(P<0.05),治疗反应无效的患者高于有效患者(P<0.05);DLBCL患者血清VEGF、β2-MG及LDH水平表达三者互相比较均呈正相关,三者与治疗有效率的对比均呈负相关(P<0.05)。结论:DLBCL患者血清β2-MG、VEGF及LDH水平较高,且在治疗后呈明显下调,三者表达水平的变化均与患者临床分期、骨髓侵犯、IPI指数和治疗反应相关,提示其可作为DLBCL患者疾病监测、治疗疗效和预后评估的依据。

Switchable dry adhesive based on shape memory polymer with hemispherical indenters for transfer printing

Transfer printing based on switchable adhesive is essential for developing unconventional systems,including flexible electronics,stretchable electronics,and micro light-emitting diode(LED)displays.Here we report a design of switchable dry adhesive based on shape memory polymer(SMP)with hemispherical indenters,which offers a continuously tunable and reversible adhesion through the combination of the preloading effect and the thermal actuation of SMP.Experimental and numerical studies reveal the fundamental aspects of design,fabrication,and operation of the switchable dry adhesive.Demonstrations of this adhesive concept in transfer printing of flat objects(e.g.,silicon wafers),three-dimensional(3D)objects(e.g.,stainless steel balls),and rough objects(e.g.,frosted glasses)in two-dimensional(2D)or 3D layouts illustrate its unusual manipulation capabilities in heterogeneous material integration applications.

Isolation and Identification of Symbiotic Bacteria from <i>Brasenia schreberi</i>and Analysis of their Polysaccharide Producing Characteristics and Antioxidant Activity

Brasenia schreberi (water shield), a perennial freshwater aquatic plant of the family Nymphaeaceae, is rich in polysaccharides with positive biological activity and potential application value. As an indicator plant of the environment in wetlands, B. schreberi original and wild water environment faced increasing deterioration and has been listed as a critically endangered species in several countries of East Asia. Seeking an alternative method to produce B. schreberi mucilage polysaccharide is of top priority. The morphological structure of the stem and leaf of B. schreberi was studied. Well-developed glandular cells and aerenchyma tissue were observed in the stem and leaves of water shield, which were related to its aquatic habitat and polysaccharide secretion and then three endophytic bacteria were successfully isolated and purified from its stem and leaf and identified as Micromonospora sp. YG-1, Xylariaceae sp. strain UT-X and Psychrobacter pulmonis strain T-15. Symbiotic bacteria from B. schreberi produced polysaccharides with similar spectral peaks and chemical functional groups to those of B. chinensis. Further, analysis of hydroxyl free radicals showed that symbiotic bacteria in water shield had significant antioxidant activity against hydroxyl free radicals. This study provides a theoretical and practical basis for further study using symbiotic bacteria to produce polysaccharides to overcome the environmental limitations of the growth and development of B. schreberi.

Low levels of low-density lipoprotein cholesterol and cognitive decline

The relationship between low levels of serum low-density lipoprotein cholesterol(LDL-C)and subsequent cognitive decline remains unclear.The present study aimed to evaluate the longitudinal association between low LDL-C levels and cognition decline in the context of the current aggressive guideline-recommended targets(LDL-C levels less than 55 mg/dL for individuals at very high risk of cardiovascular events,and less than 70 mg/dL for high risk individuals).Data from wave 13(2016)to wave 14(2018)of the Health and Retirement Study(HRS)were utilized.LDL-C concentrations measured at wave 13 were categorized into 5 levels,reflecting currently recommended values for lipid lowering treatment.Of 7129 included participants(mean age:69.0±9.9 years,60.3%female),we found that compared to participants with LDL-C levels of 70.0-99.9 mg/dL,those with LDL-C levels of<55 mg/dL had significantly slower 2-year decline rates in global cognitive function(0.244 point/year;95%confidence interval(CI):0.065-0.422;P=0.008),working memory(0.068 point/year;95%CI:0.004-0.133;P=0.038),and borderline significantly in episodic memory(0.155 point/year;95%CI:-0.004-0.315;P=0.057).Similarly,significantly slower decline rates were observed in those with LDL-C levels of 55.0-69.9 mg/dL.The present study demonstrated that compared with LDL-C levels 70.0-99.9 mg/dL,low LDL-C levels(<70 mg/dL,especially<55 mg/dL)were associated with significantly slower cognitive decline in population-based setting.Future randomized controlled trials are warranted to ascertain the safety and benefit of current aggressive guideline-recommended targets on cognitive function.

Hypervalent iodine-mediated gem-difluorination of vinyl halides enabled by exclusive 1,2-halo migration

β-Difluorinated alkyl halides are of significant value in the modular synthesis of gem-difluorinated molecules.An exclusive 1,2-halo migratory gem-difluorination of vinyl halides with in situ-generated PhIF_(2)·HF is described.This protocol provides a general and practical approach towards a wide variety ofβ-difluorinated alkyl bromides.Bothα-andβ-bromoalkyl alkenes are suitable substrates,leading to two distinct types of products.The extension of this protocol to vinyl chloride and iodide are also feasible.The synthetic versatility of this method has been highlighted by the late-stage modification of complex small molecules and further transformations of theβ-difluorinated alkyl halides to valuable CF_(2)-containing compounds.

Effects of secukinumab and adalimumab on serum uric acid level in patients with plaque psoriasis

Background:Psoriasis is a chronic systemic inflammatory disease,and hyperuricemia is a common comorbidity in patients with psoriasis.However,there are limited reports on the relationship between serum uric acid levels and biological treatment efficacy.The purposes of this study were to compare the differences in serum uric acid levels between patients with psoriasis and healthy controls and analyze the risk of hyperuricemia.Methods:A total of 196 patients with psoriasis and 191 age-and sex-matched healthy controls were enrolled in this retrospective cohort study.One hundred and twenty-seven patients with severe psoriasis were treated with biologics.Sixty-eight patients received adalimumab,and 59 patients received secukinumab.Serum uric acid levels were measured at baseline,week 24,and week 48 of treatment.Results:Patients with psoriasis had higher serum uric acid levels than healthy controls(6.4±1.7 mg/dL vs.5.7±1.5 mg/dL,P<0.001).Hyperuricemia was found in 33.7%(66/196)of patients with psoriasis,which was significantly higher than that in healthy controls(13.1%[25/191],P<0.001).Serum uric acid levels and hyperuricemia were not related to the severity of psoriasis(P>0.05).No significant changes in serum uric acid levels and hyperuricemia were observed following adalimumab treatment(P>0.05).The serum uric acid level in patients treated with secukinumab was 6.7±1.6 mg/dL at week 24,which was not statistically different from that at baseline(6.6±1.4 mg/dL,P=0.885).Serum uric acid levels were significantly decreased at week 48(6.3±1.5 mg/dL vs.6.6±1.4 mg/dL,P=0.007)in patients treated with secukinumab.Secukinumab had no significant effect on hyperuricemia either(P>0.05).Conclusions:The serum uric acid levels and prevalence of hyperuricemia in patients with psoriasis were significantly higher than those in healthy controls.Secukinumab treatment for 48 weeks successfully decreased serum uric acid levels in patients with psoriasis,whereas adalimumab had no significant effect on serum uric acid levels.

绿色火炸药进展与未来

战争数字化、信息化和智能化推动着火炸药技术向绿色方向发展.目前,火炸药的生产制造及使用过程会产生有毒有害物质,对自然环境和人类健康造成不良影响.绿色火炸药在不影响产品性能的前提下,能够在全生命周期内最大程度减少对环境与作业人员的影响,降低武器特征信号及有害现象等,是实现火炸药可持续发展的必然选择.本文从近年来绿色含能化合物的创新合成、绿色工艺及加工技术以及废药再利用等方面进行综述.首先,总结氮杂环基化合物和全氮离子化合物的创新合成及理化性能.其次,总结合成中绿色合成或加工技术,包括绿色合成和绿色介质、发射药绿色工艺和绿色固体氧化剂研究进展.再次,对废药处置中近年来生物降解、资源化利用进行综述与评价.最后,指出绿色火炸药相关研究未来的发展方向.

1,4-硼氮杂芳烃在中国的研究进展

稠环芳烃及其衍生物在有机光电材料领域具有广泛应用,杂原子掺杂可有效调节稠环芳烃的物理化学性质.硼氮杂芳烃是稠环芳烃的重要成员.基于硼原子和氮原子的相对位置,硼氮杂芳烃可以分为三种异构体:1,2-硼氮杂芳烃、1,3-硼氮杂芳烃和1,4-硼氮杂芳烃,由于合成上的困难,1,3-硼氮杂芳烃的研究相对较少.近年来,得益于1,4-硼氮杂芳烃在多重共振热活化延迟荧光材料方面潜力的发掘,1,4-硼氮杂芳烃在国内外都取得了飞速发展.我国有机化学及材料化学领域的学者们积极参与并推动了1,4-硼氮杂芳烃的快速发展,在1,4-硼氮杂芳烃的结构开发和应用拓展方面开展了一系列原创性的工作,取得了瞩目的成绩.以1,4-硼氮芳烃的结构作为线索,按照杂原子二元掺杂(B/N)骨架和三元掺杂(X/B/N)骨架分别进行论述,综述了1,4-硼氮杂芳烃的合成发展历史和应用研究拓展,最后对硼氮杂芳烃领域的未来发展与应用进行了展望.

Relationships of Residential Distance to Major Traffic Roads with Dementia Incidence and Brain Structure Measures:Mediation Role of Air Pollution

Background:Uncertainty exists regarding the operating pathways between near-roadway exposure and dementia incidence.We intend to examine relationships between proximity to major roadways with dementia incidence and brain MRI structure measures,and potential mediation roles of air and noise pollution.Methods:The cohort study was based on the UK Biobank.Baseline survey was conducted from 2006 to 2010,with linkage to electronic health records conducted for follow-up.Residential distance to major roadways was ascertained residential address postcode.A land use regression model was applied for estimating traffic-related air pollution at residence.Dementia incidence was ascertained using national administrative databases.Brain MRI measures were derived as imagederived phenotypes,including total brain,white matter,gray matter,and peripheral cortical gray matter.Results:We included 460,901 participants[mean(SD)age:57.1(8.1)years;men:45.7%].Compared with individuals living>1,000 m from major traffic roads,living≤1,000 m was associated with a 13%to 14%higher dementia risk,accounting for 10%of dementia cases.Observed association between residential distance and dementia was substantially mediated by traffic-related air pollution,mainly nitrogen dioxide(proportion mediated:63.6%;95%CI,27.0 to 89.2%)and PM2.5(60.9%,26.8 to 87.0%).The shorter residential distance was associated with smaller volumes of brain structures,which was also mediated by traffic-related air pollutants.No significant mediation role was observed of noise pollution.Conclusions:The shorter residential distance to major roads was associated with elevated dementia incidence and smaller brain structure volumes,which was mainly mediated by traffic-related air pollution.

铁棍山药微型块茎遗传转化体系的建立

怀山药(Dioscorea opposita)遗传转化是对其进行基因功能分析和遗传改良的基础,但目前国内外尚未见相关报道。以怀山药优良品种铁棍山药(D. opposita cv.‘Tiegun’)的微型块茎为受体材料,对影响遗传转化的因素进行优化,建立了由根癌农杆菌介导的山药遗传转化体系。过表达质粒载体p CAMBIA1301-DoSERK2含GUS标记基因和潮霉素(Hyg)抗性筛选基因,沉默质粒载体pART27-DoSERK2含卡那霉素(Kan)抗性筛选基因。根癌农杆菌抑制剂特美汀(Tim)的最佳浓度为500mg·L^(–1);再生芽和生根时, Hyg的最佳浓度分别为15和20 mg·L^(–1), Kan的最佳浓度分别为120和160 mg·L^(–1)。对转化植株进行PCR和GUS组织化学检测,结果显示外源基因已整合到铁棍山药转基因株系的基因组中并在细胞中表达。该研究建立了一套取材便利的铁棍山药遗传转化方法,对其它品种山药的转化也具有参考价值。

怀牛膝细胞悬浮培养条件的优化

为进一步优化怀牛膝(Achyranthes bidentata)细胞悬浮培养条件,对接种量、继代周期、pH、光照及Cu2+等多种影响因子的作用效果进行了研究,以提高怀牛膝细胞生长量及牛膝多糖含量。结果显示,接种量50 g·L^–1、继代周期14天,pH5–6和光照培养可以使细胞保持良好的生长状态及多糖合成能力;添加50μmol·L^–1 Cu^2+,细胞的干重最大,可达44.63 g·L^–1,多糖含量也最高,为4.02 mg·g^–1。

DNS权威服务器FPGA加速技术研究

现有DNS权威服务器处理DNS请求及响应报文依赖软件网络协议栈, CPU资源占用率高、开销大,处理性能受限.本文基于SmartNIC架构对DNS权威服务器的功能进行卸载加速,提出并设计了高性能DNS权威查询响应流水线PHDR Pipe (perfect Hash DNS response pipeline),基于完美哈希(perfect Hash)实现对区文件的预先处理,避免哈希冲突导致的多次访存,降低流水线最坏情况下处理延迟,从而有效提升系统吞吐率并降低响应延迟.基于开源的FAST平台的实验结果表明,与通用的BIND9系统相比响应延迟降低了约10倍,吞吐量接近10 Gb链路线速,同时资源开销小且具有良好的可扩展性.