Measles virus DNA vaccination: antibody isotype is determined by the method of immunization and by the nature of both the antigen and the coimmunized antigen

Plasmids encoding the measles virus hemagglutinin (HA) and nucleoprotein (NP) proteins inoculated into the skin of BALB/c mice by the gene gun method induced both humoral and cytotoxic lymphocyte class I-restricted immune responses. Although intramuscular immunization induces the immunoglobulin G2a (IgG2a) antibody isotype for both antigens, with gene gun immunization, the NP still generated mainly IgG2a and the major isotype induced by the HA was IgG1. Interestingly, gene gun coimmunization of HA and NP plasmids resulted in a dominant IgG1 HA response and the switching of antibodies generated against the NP to the IgG1 isotype.     

Social mobility and 21 year mortality in a cohort of Scottish men

Effective immunization against the murine B16 melanoma by a nonviral approach in which a gene gun is used to transfer GM-CSF cDNA into tumor cells has been described. We have extended this nonviral approach by using the poorly immunogenic murine myeloma MPC11 model. Vaccination with the transfected, GM-CSF-expressing MPC11 cells induced a potent antitumor cytotoxic T lymphocyte response associated with tumor rejection in the majority of the test mice. Furthermore, nearly 100% (27 of 28) of the tumor-free mice were able to reject a tumor rechallenge. While this approach is clinically attractive because of minimal tissue manipulation/culturing and the absence of infectious agents, a number of tested human primary tumors, including myeloma cells, have failed to produce high levels of GM-CSF after gene gun transfection. To circumvent the low transfection efficiency in certain human tumor cells, we showed that combining irradiated tumor cells to provide tumor antigens together with gene gun-transfected fibroblasts to provide GM-CSF induced effective tumor rejection. We also report that normal human skin fibroblasts transfected by the gene gun produce high levels of human GM-CSF (250 ng/10(6) cells/24 hr). These results suggest that combining irradiated tumor cells with gene gun-transfected fibroblasts results in antitumor immune responses and may allow for a wider application of this approach to cancer immunotherapy.     

In vivo gene transfer methods into bladder without viral vectors

For the application of gene therapy to bladder cancer, we examined four in vivo gene transfer methods without viral vectors. For lipofection cationic liposomes (Lipofectin) were instilled into murine bladders. The hemagglutinating virus of Japan (HVJ)-liposomes possessing membrane fusion activity were also injected intraluminally. Using a particle gun, rabbit bladder mucosa was bombarded with DNA-coated gold microcarriers. Electrotransfection was examined in rabbit bladder by pulse direct currents (0.15-0.2 A, 50 msec, repeated 8 times) generated between needle electrodes after submucous injection of DNA solution. beta-galactosidase gene and chloramphenicol acetyltransferase (CAT) gene were used as marker genes. Although lipofection was inefficient in normal urothelium, cancerous urothelium was transfected slightly. HVJ-liposomes more efficiently transfected superficial layers of urothelium with a peak of expression on day 5. The particle gun produced non-uniform but efficient transfection in deeper layers of the urothelium. By electrotransfection, submucous interstitial cells were transfected as well as urothelium. No major complications were observed after these four procedures. HVJ-liposomes are potentially useful for the treatment of carcinoma in situ and the latter two methods may be suitable for the adjuvant therapy of localized bladder tumors.     

Canine distemper virus DNA vaccination induces humoral and cellular immunity and protects against a lethal intracerebral challenge

We have studied the immune responses to the two glycoproteins of the Morbillivirus canine distemper virus (CDV) after DNA vaccination of BALB/c mice. The plasmids coding for both CDV hemagglutinin (H) and fusion protein (F) induce high levels of antibodies which persist for more than 6 months. Intramuscular inoculation of the CDV DNA induces a predominantly immunoglobulin G2a (IgG2a) response (Th1 response), whereas gene gun immunization with CDV H evokes exclusively an IgG1 response (Th2 response). In contrast, the CDV F gene elicited a mixed, IgG1 and IgG2a response. Mice vaccinated (by gene gun) with either the CDV H or F DNA showed a class I-restricted cytotoxic lymphocyte response. Immunized mice challenged intracerebrally with a lethal dose of a neurovirulent strain of CDV were protected. However, approximately 30% of the mice vaccinated with the CDV F DNA became obese in the first 2 months following the challenge. This was not correlated with the serum antibody levels.     

料仓清堵助流装置—空气炮的应用

料仓内物料起拱、堵塞是一较普遍存在的问题，采用空气炮破拱、清堵，改善料仓内物料的流动性是一种较理想的方法。本文介绍了国内外有关空气炮的开发研制和应用情况，以及空气炮的功能、特点和工作原理，给出了空气炮喷爆能量的计算方式，并对空气炮的选用方法及安装要点作了介绍，可供参考。     

Gene therapy in rheumatoid arthritis--an already feasible therapeutic principle?

INTRODUCTION: The purpose of this research study was to describe parents' behaviors, knowledge, and beliefs related to unintentional firearm injuries among children and youth. METHOD: A convenience sample of 80 parents whose children were attending one of six Kindercare Learning Centers in a Southwestern city was surveyed during the summer of 1995 to learn about their behaviors, knowledge and beliefs about unintentional firearm injuries among children and youth. Data on demographic characteristics, behaviors, knowledge, and beliefs, were collected with a questionnaire. RESULTS: Men and parents who had grown up with a gun in the house were more likely to be gun owners. Forty-eight percent of parents kept at least one gun in the home. Twenty-six percent of gun owners reported that the gun was loaded at all times, and 18% reported that a gun was kept within reach of a child. The most common reason given by parents for having a gun was for protection (61%). Only 8% of parents reported having discussed firearm safety with a health care worker. None of the parents had discussed firearm safety with a pediatrician. A test of knowledge about firearm injuries revealed some gaps in knowledge, with no significant differences between men and women or gun owners and non-gun owners. DISCUSSION: Results suggest that firearms in the home continue to pose a significant risk to children. Anticipatory guidance from NPs and pediatricians is needed to protect children from unintentional firearm injuries.     

3200m~3高炉泥炮液压系统的改造

泥炮是高炉炉前出铁场关键设备之一。以邯郸西区3200m3高炉泥炮液压系统为例,针对泥炮在生产中经常出现的问题,介绍了泥炮旋转和打泥控制回路的设计要点,着重阐述了控制泥炮回转速度、打泥不退炮和提高泥柄子、泥炮活塞寿命的方法。     

提高铁水纯镁脱硫喷枪寿命的实践

喷枪寿命长短直接影响铁水脱硫效果，影响铁水脱硫成本，如喷枪寿命短，将对生产组织造成一定的困难，所以在铁水脱硫中，喷枪寿命是一项重要的经济指标。     

3号高炉泥炮堵口打泥瞬时炮嘴偏移原因浅析

分析了高炉泥炮在堵口打泥瞬时炮嘴偏移的原因，并对此进行了理论验算。     

Firearm ownership and safety practices: a random-digit dial survey of San Diego

A random-digit dialing procedure was used to identify correlates of gun ownership and storage for a defined population. Of subjects contacted, 525 (64.7%) completed the survey. Subjects were generally representative of the population with slight underrepresentation of minority groups (16% were non-Caucasian). Of respondents, 129 (25.2%) reported owning a gun. Of these, 72.6% owned a handgun, 55% kept firearms for protection, 27.7% kept gun(s) loaded and ready to shoot, 66.4% kept gun(s) locked, and 46.2% carried gun(s) in the car some of the time. The strongest correlates of ownership were formal training (odds ratio [OR] = 3.52; 95% confidence intervals [CI] = 2.18, 5.67) and having been shot at (OR = 2.15; 95% CI = .97, 4.75). The strongest correlates of loaded gun status were children in the home (OR = 6.46; 95% CI = 1.18, 35.42), formal training (OR = 4.65; 95% CI = 1.04, 20.77), and keeping a gun for protection (OR = 8.82; 95% CI = .87, 89.83). Having been shot at was negatively correlated with keeping one's gun(s) locked (OR = .26; 95% CI = .07, 1.01). The strongest correlates of keeping a gun in the car were handgun ownership (OR = 11.44; 95% CI = 1.02, 128.65), keeping one's gun(s) loaded (OR = 3.79; 95% CI = 1.00, 14.43), and formal training (OR = 3.34; 95% CI = .82, 13.65). The data suggest that leaving firearms loaded and unlocked is common. Results may provide guidance in the design of interventions to decrease firearm-related morbidity and mortality.     

高 炉 喷 吹 废 塑 料 堵 枪 模 拟

 废塑料软融温度低,一般为80~250 ℃,因此高炉喷吹废塑料时可能发生堵枪。为了防止堵枪,模拟高炉风温1 250 ℃,对不同种类不同粒度的废塑料在不同直径喷枪和不同固气比等条件下,进行了热态模拟喷吹实验。对堵枪机理进行了分析,结果表明,喷吹废塑料时发生堵枪的因素很复杂,塑料种类、粒度组成、喷枪直径、温度等都与堵枪密切相关。但是,合理的粒度组成和相适应的喷枪直径、合理的喷枪结构和材质以及合理的喷吹工艺制度是防止堵枪的重要措施。     

单管煤枪的改进与应用

提高喷煤枪使用寿命和减少喷枪冷却用气量,对于防止风口磨损、保证喷煤枪投入数量、减少因风口小套内壁磨损导致的高炉临时休风、降低煤枪使用成本和高炉生产成本具有重要意义。主要介绍宝钢湛江钢铁公司针对普通单管煤枪的不足,自主研发了长寿单管煤枪,重点阐述其技术特点及其实际应用情况,实践证明该长寿单管煤枪使用效果好、寿命长,在生产中应用效果良好。     

液压泥炮的技术进步

液压泥炮是高炉炼铁的关键设备之一.介绍了国内外液压泥炮的发展情况和各个时期液压泥炮的参数性能,分析了现代液压泥炮的结构特点,指出液压泥炮朝着大型化、自动化、长寿化的方向发展,开发先进、高效、可靠的液压泥炮具有广阔的前景.     

KD75型液压泥炮的故障分析与改进

液压泥炮是高炉堵铁口的专用设备,因为泥炮故障造成的高炉慢风、休风现象较多,成为制约高炉生产的瓶颈。文章在介绍安钢450 m3高炉使用的KD75型液压泥炮结构特点及工作原理的基础上,分析液压泥炮在使用过程中出现的打泥机构吊挂系统、液压炮回转机构、打泥机构角度调整系统等故障并提出了改进措施,给出了液压泥炮使用和管理的几点建议。     

Immunization of the female genital tract with a DNA-based vaccine

Vaccines are being sought for contraception and the prevention of sexually transmitted diseases. However, progress is slow in this area largely because of lack of information on induction of protective immune responses in genital tract mucosa. In this study, we investigated whether in vivo transfection with a model DNA-based antigen delivered by gene gun technology would induce an antibody response detectable in vaginal secretions. Female rats were immunized with plasmids encoding human growth hormone (HGH) under the control of a cytomegalovirus promoter (pCMV/HGH) via vaginal mucosa (V), Peyer's patch (PP), and/or abdominal skin (S) routes. Localization of HGH in the target tissues demonstrated that all three sites can be transfected in vivo with pCMV/HGH. Vaginal tissues expressed roughly the same level of plasmid as skin. Antibodies to HGH were detectable in serum and vaginal secretions in rats immunized with pCMV/HGH. In the rats primed and boosted vaginally, vaginal immunoglobulin A (IgA) and IgG antibody titers to HGH were sustained for at least 14 weeks, whereas rats immunized via other routes and protocols (S/V, S/S, PP/PP, or PP/V) did not consistently sustain significant vaginal antibody titers beyond week 6. DNA-based immunizations administered by the gene gun may be an effective method of inducing local immunity in the female genital tract.     

引射器超声速全域化与诱导式喷砂枪

针对普通喷砂枪“能量利用率较低,喷砂效率特低” 的现状,引入了引射式暂冲型风洞扩压喷气嘴的多孔结构和 Laval 喷管完全膨胀状态设计理念,设计了风洞式喷砂枪。多孔结构缩短了混合距离,是缩小版的风洞扩压喷气嘴,喷砂管之内大部分区域是超声速气流,因而提高了引射效率。进一步地,由于风洞式喷砂枪内部仍残存有亚声速区域,喷砂效率仍未达到压入式喷砂机的水平应与此问题有一定关联性。在风洞喷砂技术的基础上设计了诱导式喷砂枪,以压力诱导方式在喷砂管内部气流全部实现了超声速 ( 超声速气流全域化 ),为砂粒加速创造更加有利的条件;力图打造一款喷砂效率效果赶超压入式喷砂机,且仍然轻便适用的喷砂枪。本文通过 CFD数值模拟喷砂枪内部的流体参数分布说明诱导式喷砂枪改造的新颖性和合理性。     

2000 m3高炉泥炮改造

介绍了2000m^3高炉泥炮的工作原理，从设计、制造、安装调试、使用维护等方面分析了产生故障的原因，找出泥炮油缸行程、缓冲结构等方面的问题，制定具体的改进措施方案。改造后高炉泥炮运行良好。     

高炉设备液压泥炮固定支架延寿技术研究与实施

简要介绍了某钢铁公司炉前设备液压泥炮在斜底座上焊接的固定支架内侧常出现断裂,致使泥炮不能正常工作,影响生产,通过现场使用分析研究,重新选材优化设计,使液压泥炮满足现场使用,达到泥炮延寿要求,生产效率得以提高,实现规模产量要求。     

火炮身管用钢现状及发展趋势

火炮身管用钢决定了身管类武器的使用性能，影响火炮的作战持续性与机动性。通过对国内外火炮身管用钢合金成分体系、制造工艺流程、材料主要性能指标总结分析，指出当前国内外炮钢主要牌号、性能水平以及存在高温性能不足的问题。通过调研国内外火炮用钢最新研究成果以及身管武器整体技术需求，总结和展望了火炮身管用钢的研究现状和发展趋势，针对大口径火炮研制高强韧炮钢以减轻壁厚和质量，针对中小口径速射火炮研制耐烧蚀性能炮钢以提高使用寿命。