一种实用型袖珍式气体检测仪的设计

针对目前使用的传统气体检测仪器因体积大、精度低,难以对储罐和管道等的漏气进行精确有效检测的缺陷,提出一种袖珍式气体检测仪的设计方案.设计方案对系统采用干电池供电,以单片机STC12C2052AD为控制核心,结合MQ-2烟雾传感器,不但对氢气、液化气和天然气等可燃气体的检测灵敏度高,而且硬件结构简单,体积小,重量轻,携带方便,非常适合漏气现场检测,具有较高的实用性.     

Validation of a high voltage leak detector for use with pharmaceutical blow-fill-seal containers--a practical approach

Proposed requirements for pharmaceutical package integrity testing outlined in the EU Guide for Sterile Medicinal Products may make it necessary to evaluate and validate alternate ways to perform 100% leak inspection. One such method is high voltage leak detection (HVLD). Even though HVLD has been used for glass ampoules and vials for years, qualification and validation strategies are not well established. In this article, we describe and discuss our practical approach to validation and the protocols used to qualify and validate a high voltage leak detector for use with blow-fill-seal containers. For this work, we used laser drilled pinholes as a model for pinholes produced during manufacturing and defined a "window diagram." This diagram allowed us to plot the parameters of influence and the settings of the HVLD in an easy to visualize pictorial display. In the validation step, we initially determined the most sensitive standard integrity test for our product and container design from the available choices, the vacuum chamber, dye bath and microbial challenge visual inspection tests. In the next phase of our work, the HVLD was crossed-validated against the most sensitive of these tests, the dye bath visual inspection test. This was accomplished with a large number of containers mixed with deliberately defective ampoules. Our conclusion from this work is that the HVLD is an appropriate and feasible integrity test for 100% inspection of blow-fill-seal containers.     

一种实用型智能消防报警器的设计

设计一种智能型消防报警器,其以单片机为核心,与DS18B20温度传感器、MQ-2烟雾传感器相结合,硬件结构简单,生产成本低,能及时稳定可靠预报火灾险情,具有较高的实用性.     

Working with laboratory animals: general principles and practical considerations

Laboratory animals play an indispensable role in research discovery and technological advances, and they will continue to yield basic, exciting, and prodigious information that can enrich the future of people and other animals. For both ethical and scientific reasons, all-individuals whose work requires the use of laboratory animals must take the time to conduct a thorough review of the literature to determine what animal models are available and which are the most relevant, and they must learn and understand the uniqueness of the selected species, breed, and strain. Scientists have the privilege, but not the right, to use animals as experimental subjects. This privilege must not be abused. Therefore, it is imperative that before working with any laboratory animal, you know your "subject."     

Computer network for a diagnostic virology laboratory

We previously reported that fucoidin (a polymer of predominantly sulfated L-fucose) significantly inhibits: (1) tight binding of human sperm to human zona pellucida in vitro and (2) stimulation of the acrosome reaction by acid solubilized human zona pellucida. Here, we determined fucoidin binding activity on human spermatozoa and its localization on both live and permeabilized human sperm populations. A typical binding curve was demonstrated with biotinylated fucoidin. In competitive inhibition assays with unlabelled fucoidin or human sperm membrane extracts, IC50's were 4.0 micrograms/ml and 31.4 micrograms/ml, respectively. Fucoidin binding was localized over the acrosomal region of methanol-fixed human sperm and this pattern of binding significantly decreased from 92 +/- 3% to 74 +/- 6% with calcium ionophore A23187 treatment (p < 0.01). Binding of fucoidin-coated beads to live (non-permeabilized) human sperm was less than 1%. Addition of the detergent, Triton-X, to permeabilize sperm membranes resulted in a significant increase in binding (p = 0.001). These results provide evidence for the presence of a fucoidin binding compound in human spermatozoa that is localized to the membranes of the acrosomal region and can be extracted by a mild detergent extraction. Absence of binding by fucoidin to intact but not permeabilized spermatozoa suggests that the heteropolysaccharide binds to a receptor within the acrosomal matrix. However, further investigation is warranted to determine whether a fucoidin binding site is present both at the sperm's surface for the initial contact with the zona pellucida, and also for secondary binding after exposure of the acrosomal membranes.     

Erectile dysfunction: a practical approach for primary care

Erectile dysfunction has been poorly recognized and managed in the past, due to its taboo aspects and erroneous perceptions of its medical significance. With research, improved understanding has guided a practical approach to its diagnosis and treatment. In most presentations, erectile dysfunction has an organic etiology. Likely causes are often discerned from the clinical history and physical examination. Management may be a simple matter of addressing correctable risk factors, or a direct intervention may need to be pursued. For an individual patient, selection of the "ideal" treatment is based on an understanding of the extent of the problem and consideration of the patient's preferences.     

Aminoglycosides: a practical review

Aminoglycosides are potent bactericidal antibiotics that act by creating fissures in the outer membrane of the bacterial cell. They are particularly active against aerobic, gram-negative bacteria and act synergistically against certain gram-positive organisms. Gentamicin is the most commonly used aminoglycoside, but amikacin may be particularly effective against resistant organisms. Aminoglycosides are used in the treatment of severe infections of the abdomen and urinary tract, as well as bacteremia and endocarditis. They are also used for prophylaxis, especially against endocarditis. Resistance is rare but increasing in frequency. Avoiding prolonged use, volume depletion and concomitant administration of other potentially nephrotoxic agents decreases the risk of toxicity. Single daily dosing of aminoglycosides is possible because of their rapid concentration-dependent killing and post-antibiotic effect and has the potential for decreased toxicity. Single daily dosing of aminoglycosides appears to be safe, efficacious and cost effective. In certain clinical situations, such as patients with endocarditis or pediatric patients, traditional multiple dosing is still usually recommended.     

Bone grafting materials for dental applications: a practical guide

A variety of grafting materials are available for use in dental applications. Autogenous bone is the material of choice because of its osteogenic properties, which allow bone to form rapidly and under conditions where significant bone augmentation or repair is required. For other dental applications, allografts and alloplasts are appropriate. Knowing the physical and chemical properties of these materials and their mechanism of action, the correct graft or combination of grafts can be selected for each situation encountered. This article discusses current bone grafting options as reported in the literature since 1984. It emphasizes acquainting the reader with currently available materials and their properties.     

Scapholunate dissociation: a practical approach for the emergency physician

The development of new techniques in sequencing nuclei acids has produced a great amount of sequence data and has led to the discovery of new relationships. In this paper, we study a method for parallelizing the algorithm WORDUP, which detects the presence of statistically significant patterns in DNA sequences. WORDUP implements an efficient method to identify the presence of statistically significant oligomers in a non-homologous group of sequences. It is based on a modified version of the Boyer-Moore algorithm, which is one of the fastest algorithms for string matching available in the literature. The aim of the parallel version of WORDUP presented here is to speed up the computational time and allow the analysis of a greater set of longer nucleotide sequences, which is usually impractical with sequential algorithms.     

Pharmacogenetics: a laboratory tool for optimizing therapeutic efficiency

Pharmacogenetics is the study of the linkage between an individual's genotype and that individual's ability to metabolize a foreign compound. Differences in metabolism of therapeutics can lead to severe toxicity or therapeutic failure by altering the relation between dose and blood concentration of the pharmacologically active drug. Phenotypes exhibiting poor and ultraextensive metabolism result from genetic variance (polymorphism) of enzymes involved in metabolism. Thus, in pharmacogenetic studies one applies genotyping of polymorphic alleles encoding drug-metabolizing enzymes to the identification of an individual's drug metabolism phenotype. This knowledge, when applied to dosing or drug selection, can avoid adverse reactions or therapeutic failure and thus enhance therapeutic efficiency. More than 25 commonly prescribed medicines are metabolized by the cytochrome P-4502D6 (CYP2D6) isoenzyme, and polymorphism of the CYP2D6 gene affects the therapeutic management of up to 17% of individuals in some ethnic groups. In this review, we summarize and update information concerning drug-metabolizing genotypes with emphasis on CYP2D6 genotyping techniques that can be applied by the clinical laboratory for linking human genetics to therapeutic management.     

小型烧结实验设备的开发

比较分析了现有的两种烧结实验设备的优缺点,在此基础上研究开发了一套更理想的实验方案及相应设备,即小型烧结实验机.此设备具有制造成本低廉、安装简单、模拟性好、可操作性强、劳动强度低等优点.依实验需要,通过调整和改变部分工艺参数,能获得更高质量的不同性能的烧结矿成品,并可制成大量的烧结矿试样.结合其它相关设备可对烧结矿的性能进行广泛的研究,能轻易获得更多的实验数据,从而为工业生产提供更准确的理论依据.     

应用于无线传感网频率合成器的0.5V低电压鉴频鉴相器设计

基于0.13μm CMOS技术设计了一个应用于无线传感网频率合成器、电源电压为0.5 V的鉴频鉴相器.它的功能是比较输入信号的频率和相位差,并输出一个与该差值成比例的电压.因电源电压是0.5 V,所以该电路采用低阈值晶体管.为了增大相位误差的检测范围和提高最大工作频率,该电路采用了脉冲锁存的结构.当输入信号频率为2 MHz时,测得的相位误差检测范围为-358°～358°.与传统数字鉴频鉴相器相比,该电路具有较快的捕获速度.当输入信号的频率为2 MHz且相位误差为0°时,电路的功耗为1.8μW,并且最大工作频率为1.25 GHz.