物质安全评价学的构建研究

为完善安全物质学学科体系,有效利用物质本质安全特性,预防和控制物因事故发生,提出物质安全评价学定义,并从研究目的及研究对象等方面解析其内涵。根据其学科性质,从理论和应用两个方面建立包括物质风险评价理论、物质风险控制理论、物质健康风险评价、物质生态风险评价、物质事故风险评价5个分支的物质安全评价学研究内容体系。在此基础上,概述物质危害性辨识-物质风险分析-物质风险评估-物质风险控制四步骤的研究程序,并给出各程序的具体内容及研究方法。所做研究明确了物质安全评价学的基本学科体系,系统化了物质安全评价学的研究方法。     

生物多样性学发展中几个基本问题的探讨

近10年来,生物多样性科学的理论和方法取得了显著进展,高度交叉学科-“生物多样性学”孕育而生。但是,诸如生物多样性的生态系统功能、生物多样性与生态系统过程、生物多样性的测度、生物多样性的维持格局与丧失机制等一直是研究的热点和难点,仍在讨论和争论中发展。本文从生物多样性学的理念出发,对生物多样性研究中几个基本问题进行探讨,分析了生物多样性学框架的科学范畴。指出构建以生物多样性保育为核心目标的生物多样性学科体系和框架是生物多样性研究发展的必要。生物多样性学应始终重视实验研究和理论演绎,并不断重视哲学和思维过程。     

城市轨道交通危险因素分析与评价

针对城市轨道交通影响安全因素众多的特点，本文从人-机-环-管理四方面出发，分析了城市轨道交通在建设及运营过程中存在的各种危险因素，并用层次分析法对各种危险因素进行了权重计算，得出了各种危险因素的排序。针对排序结果提出合理的预防和控制对策，从而为改善城市轨道交通安全状况，减少事故发生提供科学依据。     

法国数学家塞尔荣获首届阿贝尔数学奖

挪威科学院日前在挪威首都奥斯陆宣布 ,把首届阿贝尔奖授予法国数学家让 -皮埃尔·塞尔 ,以表彰他在数学领域所作出的杰出贡献。在授奖决定中 ,挪威科学院称赞塞尔通过努力赋予了拓扑学、代数几何学和数字学等许多数学领域以“现代的形式” ,成为“当代最杰出的数学家之一”。今年 76岁的塞尔现为法国法兰西学院荣誉教授 ,并被许多国家的大学授予名誉博士头衔。阿贝尔奖是挪威政府 2 0 0 2年为纪念挪威天才数学家尼尔斯·亨利克·阿贝尔出资设立的一项数学大奖。阿贝尔在 5次方程和椭圆函数研究方面远远地走在了当时研究水平的前面 ,但因学…     

海洋沉积动力学研究与应用前景展望

海洋沉积动力学正在打破传统，走向海洋工程学、物理海洋学和地质学的联合，共同建立一门综合性的、统一的沉积动力学。其技术手段包括：悬沙输运的动力学模型方法、以力学为基础的半经验公式、经验公式、人工和天然示踪沉积物技术、地貌学信息方法、沉积学信息方法、以及现场直接观测。国际国内的研究动态均表明，这些方法的建立和完善将为海洋沉积动力学在海底地貌演化、生态系统的维护和改造、人类活动对环境影响的评估、海洋资源开发和持续发展战略制定等方面的应用 提供广阔的前景。     

宇宙膨胀与宇宙学距离

由于宇宙的膨胀和光速的有限性，引出了种种宇宙学距离的定义.出于当前各种教材与研究中宇宙学距离的定义不完整、甚至混淆的情况，本文总结了各种宇宙学距离的定义及其物理意义，以及它们之间的相互关系，并比较了空宇宙、爱因斯坦-德西特宇宙和加速宇宙模型下的各种宇宙学距离。     

神经科学领域前沿发展态势研究：基于ESI研究前沿的深度挖掘分析

本文构建了基于ESI研究前沿的深度挖掘方案，通过研究前沿之间的共被引网络聚焦领域研究热点、主题词共现识别神经科学领域研究重点主题；利用KeyBERT模型对研究前沿核心文献和施引文献的标题与摘要进行关键词识别，分析关键词热度年际变化，深入揭示神经科学领域研究前沿热点发展趋势；通过对研究前沿核心文献及其施引文献和参考文献进行国别分析，反映世界各国在神经科学领域研究前沿发展的学科影响力，并进一步分析中国在神经科学领域研究前沿的覆盖度和活跃度。分析表明：阿尔茨海默病、帕金森病、多发性硬化症等神经系统疾病是全球神经科学领域研究最广泛深入的重点主题，脑机接口、血清神经丝轻链蛋白、非侵入性脑刺激技术等是近年来的新兴研究热点，感染新冠病毒对神经系统的影响、新冠肺炎病人的神经系统表现以及一线医务人员的心理健康等疫情相关主题也成为近两年神经科学领域的研究热点。近年来我国在神经科学领域研究前沿的覆盖度和活跃度升高，研究前沿引领度、贡献度和参与度均有较大提升，在新冠疫情相关主题、肠道微生物菌群、靶向治疗、人工感觉神经等研究方向具有一定发展优势，在阿尔茨海默病、脑功能网络、卒中、神经性疼痛、胶质瘤等方向具有一定...     

复杂性与不确定性：无线通信面临的双重挑战

深空通信、移动通信、军事通信等领域的发展面临新的难题，其核心挑战之一在于无线通信处理中存在难以克服的各种复杂性与不确定性的问题，如何实现突破已成为当今无线通信研究的前沿热点．本文以人工智能、蜂窝无线网络等发展为启示，介绍了一种基于结构处理的研究视角，并以无线通信中信息表征和信道编码等环节为例，在分析复杂性与不确定性问题的基础上，通过相应的结构处理有效克服无线通信的相关难题，并探讨了无线通信理论与技术发展的新途径．     

2-氯丙酸的生产技术概况

2-氯丙酸是合成农药、染料和农林化学品的重要原料。本文缘述了国内外2-氯丙酸的合成方法及各种方法的工艺条件，分析了各种方法的优缺点，并展望了2-氯丙酸合成路线的发展趋势。     

基于政府投入的美国再生医学研究态势分析

为掌握美国再生医学研究态势,本文对美国联邦政府资助的再生医学项目金额、数量、资助机制、资助对象、研究方向等内容进行统计与聚类分析,发现近年来资助项目的数量和金额整体呈上升趋势,类型以竞争性定向研究为主,兼顾人才培养、培训和基础设施建设,资助对象以高校为主。资助的再生医学研究可被划分为以干细胞、生物技术、神经科学、遗传学以及消化系统疾病为代表的5大研究领域,具体来看,干细胞研究、生物技术、遗传学受到持续关注,神经科学、罕见病、损伤、儿科等方向研究热度上升,相比之下,癌症、心脏病和脑病方向的研究热度降低。干细胞研究中,基于人类的干细胞研究资助增长趋势高于非人类干细胞研究。     

Towards progress on DNA vaccines for cancer

Cancer immunotherapy faces many obstacles that include eliciting immune reactions to self antigens as well as overcoming tumor-derived immunosuppressive networks and evasion tactics. Within the vaccine arsenal for inhibiting cancer proliferation, plasmid DNA represents a novel immunization strategy that is capable of eliciting both humoral and cellular arms of the immune response in addition to being safely administered and easily engineered and manufactured. Unfortunately, while DNA vaccines have performed well in preventing and treating malignancies in animal models, their overall application in human clinical trials has not impacted cancer regression to date. Since the establishment of these early trials, progress has been made in terms of increasing DNA vaccine immunogenicity and subverting the suppressive properties of tumor cells. Therefore, the success of future plasmid DNA use in cancer patients will depend on combinatorial strategies that enhance and direct the DNA vaccine immune response while also targeting tumor evasion mechanisms. Received 2 April 2007; received after revision 14 May 2007; accepted 21 May 2007     

Immunoglobulin-binding proteins in ticks: new target for vaccine development against a blood-feeding parasite

Humans have a long history of trying to control ticks. At first, attempts focused on modifying the habitat, whereas later efforts relied heavily on the use of chemicals. Current research is directed at finding a vaccine against ticks. A strategy of targeting 'concealed antigens' succeeded with the first commercialised vaccine against the cattle tick Boophilus microplus. However, vaccine development against other tick species appears unsatisfactory to date. Vaccination depends on a specific antibody-mediated immunoreaction that damages the parasite. Immunoglobulin molecules of vertebrate hosts can pass through gut barriers into the haemolymph of ectoparasites while retaining antibody activity. Research on the ixodid tick Rhipicephalus appendiculatus revealed that host immunoglobulin-G in the parasite was excreted via salivation, during feeding. Immunoglobulin-binding proteins in tick haemolymph and salivary glands are thought to be responsible for such excretion. The discovery of an immunoglobulin excretion system in ticks indicates that they have a highly developed mechanism to protect themselves from their host's antibody attack. Such a mechanism questions whether immunization strategies will be effective against ticks, unless they circumvent or disable the ticks' immunoglobulin excretion system.     

Evaluation of oral vaccination against mouse-typhoid in a new animal model

Summary In a simple, new animal model the spread of mouse-typhoid within a mouse-colony was studied and oral vaccination against this disease was evaluated. Live vaccine was superior to inactivated vaccine.     

Retention of<Emphasis Type="Italic">B. burgdorferi</Emphasis> pathogenicity and infectivity after multiple passages in a co-culture system

In vitro cultivation ofB. burgdorferi in BSK medium results in the loss of infectivity and pathogenicity after repeated passages. To prevent this loss, a feeder layer of tibio-tarsal joint tissue derived from newborn LEW/N rats was grown on Cytodex 3 microcarriers in ESG (formerly BSKE), a novel medium developed to support the growth of both the feeder layer andB. burgdorferi. A new pathogenic isolate (FNJ) and a high passage, non-pathogenic strain (TNJ) grew well in this co-culture system with high yields of viable organism. FNJ caused no growth inhibition or visible damage to the cells in the feeder layer. FNJ remained arthritogenic for newborn LEW/N rats after 22 passages in the co-culture system, but lost its arthritogenicity after 7 passages when cultured in BSK medium. This borrelia-mammalian tissue co-culture technique presents an experimental system to study the long term interactions ofB. burgdorferi with the infected host tissues in vitro, as well as facilitate diagnostic tests and vaccine development.     

Display of proteins on Bacillus subtilis endospores

The targeting and anchoring of heterologous proteins and peptides to the outer surface of bacteriophages and cells is becoming increasingly important, and has been employed as a tool for fundamental and applied research in microbiology, molecular biology, vaccinology, and biotechnology. Less known are endospores or spores produced by some Gram-positive species. Spores of Bacillus subtilis are surrounded by a spore coat on their outside, and a few proteins have been identified being located on the outside layer and have been successfully used to immobilize antigens and some other proteins and enzymes. The major advantage of spores over the other published systems is their synthesis within the cytoplasm of the bacterial cell. Therefore, any heterologous protein to be anchored on the outside does not have to cross any membrane. Furthermore, spores are extremely resistant against high temperature, irradiation and many chemicals, and can be stored for many years at room temperature.     

Putting endotoxin to work for us: Monophosphoryl lipid A as a safe and effective vaccine adjuvant

The development of non-infectious subunit vaccines greatly increases the safety of prophylactic immunization, but also reinforces the need for a new generation of immunostimulatory adjuvants. Because adverse effects are a paramount concern in prophylactic immunization, few new adjuvants have received approval for use anywhere in the developed world. The vaccine adjuvant monophosphoryl lipid A is a detoxified form of the endotoxin lipopolysaccharide, and is among the first of a new generation of Toll-like receptor agonists likely to be used as vaccine adjuvants on a mass scale in human populations. Much remains to be learned about this compound’s mechanism of action, but recent developments have made clear that it is unlikely to be simply a weak version of lipopolysaccharide. Instead, monophosphoryl lipid A’s structure seems to have fortuitously retained several functions needed for stimulation of adaptive immune responses, while shedding those associated with pro-inflammatory side effects. Received 25 April 2008; received after revision 05 June 2008; accepted 10 June 2008     

Major contribution of codominant CD8 and CD4 T cell epitopes to the human cytomegalovirus-specific T cell repertoire

Human cytomegalovirus (HCMV) infection or reactivation is a cause of morbidity and mortality in immunocompromised individuals. In immunocompetent individuals, in contrast, HCMV is successfully controlled by specific CD8 and CD4 T cells. Knowledge of CD8 and CD4 T cell epitopes from HCMV and their immunodominant features is crucial for the generation of epitope-specific T cells for adoptive immunotherapy and for the development of a peptide-based HCMV vaccine. Therefore, we investigated the natural frequencies of a large number of CD8 and CD4 T cell epitopes, including 10 novel ones. We determined several epitopes as immunodominant. Surprisingly, no clear hierarchies were found for CD8 T cell epitopes, indicating codominance. These results will be valuable for adoptive transfer strategies and support initiatives towards development of a peptide-based HCMV vaccine.Received 12 August 2004; received after revision 24 September 2004; accepted 29 October 2004 These authors contributed equally to this work.     

Synthesis ofO 1.5-(β-D-galactopyranosyl) [DMet2, Hyp5] enkephalin amide,a new highly potent analgesic enkephalin-related glycosyl peptide

Summary A new series of O-glycosyl enkephalins has been prepared, following a convergent strategy, with high chemical yields. The galactosyl analogue,O ^1.5-(-D-galactopyranosyl) [DMet², Hyp⁵] enkephalin amide proved to be one of the most potent in vivo opioid agonists synthesized up to now.     

Malaria vaccine

Summary Among infectious diseases caused by protozoa, malaria is still the greatest killer of children. Mortality in adults living in endemic areas is significantly lower because they frequently acquire partial or complete immunity to the major pathogen,Plasmodium falciparum. This natural protection indicates that vaccination may be possible, and the first candidate antigens were cloned with the use of human immune sera as probes. Genetic and biochemical analysis of the parasite proteins revealed that they are polymorphic, and frequently gene sequences were discovered which were specific for a particular parasite isolate, which eliminated most antigens for purposes of vaccine development. The most promising candidate antigens today are the major surface proteins of sporozoites and blood stage parasites. However, the immune response against those is not sufficient for complete protection, and additional, intensive research is necessary to identify new molecules to be included in a vaccine cocktail against malaria. The current spread of the disease due to increasing drug resistance of parasites and mosquito vectors emphasizes the urgent need for a vaccine.     

Malaria vaccine

Among infectious diseases caused by protozoa, malaria is still the greatest killer of children. Mortality in adults living in endemic areas is significantly lower because they frequently acquire partial or complete immunity to the major pathogen, Plasmodium falciparum. This natural protection indicates that vaccination may be possible, and the first candidate antigens were cloned with the use of human immune sera as probes. Genetic and biochemical analysis of the parasite proteins revealed that they are polymorphic, and frequently gene sequences were discovered which were specific for a particular parasite isolate, which eliminated most antigens for purposes of vaccine development. The most promising candidate antigens today are the major surface proteins of sporozoites and blood stage parasites. However, the immune response against those is not sufficient for complete protection, and additional, intensive research is necessary to identify new molecules to be included in a vaccine cocktail against malaria. The current spread of the disease due to increasing drug resistance of parasites and mosquito vectors emphasizes the urgent need for a vaccine.