Electrocardiographic and respiratory responses to viscerotropic and neurotropic strains of Newcastle disease virus measured by radio telemetry

Two groups each of White Rock chickens from 6 to 23 weeks old were monitored by radio telemetry to determine their electrocardiogram and respiration response after they were infected with either a velogenic viscerotropic isolate of Newcastle disease virus (VVND) or the neurotropic GB strain of Newcastle disease virus (NGB). Significant changes were found in the heart rate, R wave amplitude, ST segment elevation, T wave amplitude, RS complex interval, ST segment duration T wave interval, TP segment duration, PR segment duration and TP interval of the birds infected with VVND, but no significant ECG changes were found in the birds infected with NGB. There were no significant changes in respiration rate in any birds.     

Implantable control, telemetry, and solar energy system in the moving actuator type total artificial heart

The aim of this study was to determine whether a jejunal pouch would have a lower resting pressure, be more distensible, and have more interdigestive migrating myoelectric complexes and less fecal bacterial overgrowth than would an ileal pouch after proctocolectomy and pouch-distal rectal anastomosis. In six conscious dogs with a jejunal pouch-distal rectal anastomosis and six with an ileal pouch-distal rectal anastomosis (controls), pouch distensibility and motility were measured using a barostat and perfused pressure-sensitive catheters passed per anum, pouch electrical activity was recorded using chronically implanted electrodes, and the number of bacteria per gram of stool was assessed by culture. Dogs with a jejunal pouch had lower resting pouch pressures, more distensible pouches, faster frequencies of pacesetter potentials in the pouch, more phase 3 intervals of the interdigesive migrating myoelectric complex reaching the pouch, but similar numbers and types of bacteria in their stools compared to the dogs with an ileal pouch. We concluded that jejunal pouches have a lower resting pressure, are more distensible, have more cleansing contractions, but a similar fecal flora compared to ileal pouches. A jejunal pouch has features that make it an attractive alternative to an ileal pouch for pouch-distal rectal or pouch-anal canal anastomosis after proctocolectomy.     

Application of high-temperature permanent magnets Sm(Co, Fe, Cu, Zr)z in PPM focusing system

Rare earth permanent magnets Sm(Co, Fe, Cu, Zr)z with outstanding performance and high-temperture thermal stability were fabricated. Optimized by Fe content and process, Sm(Co0.72Fe0.1Cu0.1Zr0.03.03)7.5 magnet with Br>0.75 T and Hci>1300 kA/m at 300 ℃ can be obtained. According to the performance data of Sm(Co0.72Fe0.15Cu10.1Zr0.03)75, the magnetic field along central axis BZ in periodic permanent magnet (PPM) focusing system was simulated using electromagnetic field analysis software Maxwell 2D/3D. The BZ exhibited typical cosine curve along central axis, and the peak value of BZ was high enough to meet the demand of PPM focusing system at room temperature even at 200±20 ℃. Additionally, a kind of simple cooling structure for PPM focusing system was designed by setting cooling pipe between polepieces.Simulated results showed that smooth cosine curve of BZ was successfully achieved with good control of the thickness of cooling pipe.     

Oxygen consumption using the K2 telemetry system and a metabolic cart

The purpose of this study was to compare measurements of oxygen consumption (VO2), ventilation (VE), and respiratory rate (RR) between a relatively new portable, telemetry system (K2) and a system that has been shown to be valid and reliable. Duplicate measurements were made at rest and during four levels of exercise in 10 subjects. Heart rate values were comparable for exercise at the same work level during gas collection using the two systems, indicating that the metabolic stresses were similar. Oxygen consumption measurements were significantly lower using the K2 system compared with a metabolic measurement cart (MMC). There was no significant difference in VE, but RR was lower for measurements made with the MMC. Compared with the MMC, the K2 system uses a slightly different formula to calculate VO2 because the content of carbon dioxide in expired air is not measured. To determine differences resulting from the method of calculating VO2, MMC measurements were applied to the formula used by the K2 system, and K2 values were adjusted using the RER values obtained from the MMC. There were no differences between these calculated values and the values obtained directly from either the MMC or the K2 system. Consequently, we concluded that the lower VO2 values obtained with the K2 system were attributed to the method of collecting and analyzing expired air, rather than to the method of calculating VO2.     

面齿轮传动系统参数激励振动特性分析

为研究各参数对面齿轮传动系统动态特性的影响,建立了包含齿侧间隙、传动误差、时变啮合刚度、阻尼、支承和外激励等参数的系统弯-扭耦合非线性动力学模型,结合非线性动力学数值分析理论求解并得到了系统在不同参数下的分岔特性.计算结果表明,增加齿侧间隙、时变啮合刚度和传动误差会导致系统动载荷明显增大,而增加啮合阻尼则能有效降低系统的动载荷.     

盾构机双驱动大功率行星齿轮的传动原理及特性

在研究盾构机及行星齿轮机构的基础之上,针对盾构机刀盘驱动系统,提出一种新型盾构机双驱动大功率行星齿轮传动系统,分析了传动系统的原理及其结构;建立了新型传动系统的运动学模型,对该系统的传动特性进行了分析,获得了系统的传动比、系统内部的转速、扭矩的关系和变化规律;通过对比简化实验得到的结果与理论计算得到的结果,其变化规律基本一致,验证了数学模型及分析方法的正确性.双驱动大功率行星齿轮传动系统具有传动比大、承载能力强的特点,能实现低转速、大扭矩输出的功能,满足盾构机的基本工作要求,不仅可取代传统的多个电机同时驱动多个减速器的传动系统,还能实现3种不同型式的盾构机传动系统功能.     

无线遥控配风装置在空压中的应用

某公司针对空压机供风系统泄漏浪费比较严重的问题,引进了专利技术“无线遥控配风装置”,现场应用后,管网用风均衡,每年创效82.59万元.     

Interaction of the renin-angiotensin system, bradykinin and sympathetic nerves with cholinergic transmission in the rat isolated trachea

1. The present study was undertaken to investigate the interaction of the renin-angiotensin system (RAS), bradykinin and the sympathetic nervous system with cholinergic transmission in the rat airways. Experiments were performed on epithelium-intact and epithelium-denuded preparations of rat isolated trachea which had been incubated with [3H]-choline to incorporate [3H]-acetylcholine into the cholinergic transmitter stores. Tracheal preparations were subjected to electrical field stimulation (trains of 1 ms pulses, 5 Hz, 15 V) and the stimulation-induced (S-I) efflux taken as an index of transmitter acetylcholine release. 2. In both epithelium-intact and epithelium-denuded tracheal preparations, the alpha 2-adrenoceptor agonist UK14304 (0.1 and 1 microM) inhibited the S-I efflux, in a concentration-dependent manner. The inhibition of S-I efflux produced by UK14304 (1 microM) was antagonized by the selective alpha 2-adrenoceptor antagonist idazoxan (0.3 microM). Idazoxan (0.3 microM) alone had no effect on the S-I efflux. 3. Angiotensin II (0.1 and 1 microM) was without effect on the S-I efflux in either epithelium-intact or epithelium-denuded tracheal preparations. When angiotensin-converting enzyme was inhibited by perindoprilat (10 microM), angiotensin II (1 microM) was also without effect on the S-I efflux. Similarly, in the presence of idazoxan (0.3 microM), to block prejunctional alpha 2-adrenoceptors, angiotensin II (0.1 and 1 microM) did not alter the S-I efflux. When added alone, perindoprilat (10 microM) did not alter the S-I efflux. 4. In epithelium-denuded preparations, bradykinin (0.01-1 microM) inhibited the S-I efflux. In epithelium-intact preparations, there was also a tendency for bradykinin (0.1 and 1 microM) to inhibit the S-I efflux but this was not statistically significant. However, when angiotensin-converting enzyme and neutral endopeptidase were inhibited by perindoprilat (10 microM) and phosphoramidon (1 microM), respectively, bradykinin (1 microM) significantly inhibited the S-I efflux in epithelium-intact preparations as well as in epithelium-denuded preparations. The inhibition of the S-I efflux produced by bradykinin, in the combined presence of perindoprilat (10 microM) and phosphoramidon (1 microM), was unaffected by the additional presence of the cyclo-oxygenase inhibitor indomethacin (10 microM) and/or the nitric oxide synthase inhibitor NG-nitro-L-arginine (100 microM), in either epithelium-intact or epithelium-denuded preparations. 5. In conclusion, the findings of the present study suggest that airway parasympathetic nerves are endowed with alpha 2-adrenoceptors which subserve inhibition of transmitter acetylcholine release. Under the present conditions, however, transmitter acetylcholine release is not subject to transneuronal modulation by noradrenaline released from adjacent sympathetic nerves in the airways. Moreover, angiotensin II and perindoprilat do not appear to modulate acetylcholine release from parasympathetic nerves of the airways. In contrast, bradykinin inhibits acetylcholine release from airway parasympathetic nerves but this action of bradykinin is limited by the activity of epithelial angiotensin-converting enzyme and/or neutral endopeptidase. The inhibitory action of bradykinin on cholinergic transmission in the airways does not appear to involve the liberation of prostaglandins or nitric oxide.     

采用功率内环和电压平方外环的电压型PWM整流器

根据电压型PWM整流器在同步旋转dq坐标系中建立的整流器功率控制数学模型,基于功率前馈解耦,解决了有功功率和无功功率互为耦合问题.为克服整流器电流控制策略、直接功率控制策略及非线性控制策略的不足,提出了采用功率内环、直流电压平方外环电压型PWM整流器的新控制策略.由于采用直流电压平方外环,提高了整流器直流电压跟踪和功率跟踪能力,使系统具有响应快、稳定性好、抗负载扰动能力强及结构简单的优点.给出了系统控制器的设计方法.通过正常负载及负载扰动情况下的计算机仿真,证明了新控制策略的可行性.     

间隙条件下辊轧机两级传动系统动态特性分析

 为了分析含间隙等非线性因素对叶片辊轧机传动系统的动态特性影响,建立了考虑轧辊轴承座水平间隙、齿侧间隙、综合啮合误差以及时变啮合刚度等因素的叶片辊轧机两级传动系统的非线性动力学模型。采用Runge-Kutta法对非线性微分方程组进行求解。研究了不同激励频率以及不同轧辊轴承座水平间隙对辊轧机传动系统的动态特性影响。分析表明,激励频率以及间隙的增加使系统由周期运动进入了混沌运动,且振动幅值增大,对上下轧辊齿轮传动系统影响大一些,对上轧辊二级齿轮-齿条传动系统的影响小一些。     

LE2000智能射频物位计在炼钢转炉汽化系统的应用

LE2000智能射频物位计对液位的测量具有较高的可靠性、稳定性和准确性。简要介绍了LE2000智能射频物位计系统及其在炼钢转炉汽化系统的应用。     

开展引导欣赏式教学,切实贯彻新课程标准

2001版教育部课程标准(以下简称新课标)的出台,明确地宣告了应试教育时代的结束.相应的,与应试教育相配套的各种教育模式都到了该丢弃的时候了.     

Design, Specification, Installation, and Maintenance of Modular Bridge Expansion Joint Systems

Data regarding service performance and durability of modular bridge expansion joint systems were gathered through a comprehensive literature review, survey of transportation agencies, and field observations. Typical service life and desired service life targets are discussed. Maximum movement and rotation demands are given with respect to three axes. Performance and durability problems include problems that can be traced to poor design and∕or installation, wear and tear of elastomeric parts, and fastener loosening and fatigue cracking of the metal parts. Fatigue cracking has been addressed in previous research. Guidance on design, detailing, specifications, installation, and maintenance is discussed, which should reduce the problems in the first group. Problems with the elastomeric parts and fasteners are best addressed through performance tests on the modular bridge joint systems as a system. Two system performance tests, an opening movement/vibration test, and a seal push-out test are suggested for the prequalification of specific modular bridge expansion joint systems.     

冶炼分析数据采集和传输系统的设计和实现

阐述了基于冶金分析仪器群的化学成分分析数据采集和多点远程数据传输系统的设计思想,对系统开发环境、硬件总体架构、数据流程、软件模块、数据采集和传输方法以及功能特点进行了讨论,描述了一种冶炼分析数据采集和传输系统的设计和实现过程,并介绍了系统在冶金企业生产过程中的实际运行效果。同时给出了使用先进的快速分析仪器和计算机网络技术改造落后的冶炼生产工艺流程的一种思路,供冶金企业的同行们在使用信息化技术改造企业生产工艺流程时参考。     

Sexual histories, partnerships and networks associated with the transmission of gonorrhoea

We aimed to describe and compare sexual links among people with gonorrhoea, by studying patients in 2 UK departments of genitourinary medicine. Interviews were completed for 510 and 235 cases in London and Sheffield respectively. There was a greater proportion of cases in men, homosexual men, non-white and non-British people and fewer female sex workers in London. Total networks of 1738 people in London and 570 people in Sheffield were described. Large linked heterosexual networks identified in Sheffield were associated with local contact, including men with higher numbers of sexual partners. Condom use for vaginal sex was reported for 11% of heterosexual partnerships in Sheffield, and 27% in London, with little difference between regular and casual partners. It was more difficult to define networks in London due to a high proportion of relatively anonymous contacts. These difficulties suggest that research and interventions may profitably focus upon venues for meeting partners as well as partner notification.     

Noise, information transmission, and force variability.

This study was designed to test the hypothesis derived from information theory that increases in the variability of motor responses result from increases in perceptual-motor noise. Young adults maintained isometric force for extended periods at different levels of their maximum voluntary contraction. Force variability (SD) increased exponentially as a function of force level. However, the signal-to-noise ratio (MISD), an index of information transmission, as well as measures of noise in both the time (approximate entropy) and frequency (power spectrum) domains, changed according to an inverted U-shaped function over the range of force levels. These findings indicate that force variability is not directly related to noise but that force output noisiness is positively correlated with the amount of information transmitted. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Nosocomial Candida. Epidemiology, transmission, and prevention

The NNIS and the newly established SCOPE data indicate that the relative proportion of organisms causing nosocomial bloodstream infections has changed over the last decade, with Candida species now being firmly established as one of the most frequent agents. The epidemiology of nosocomial candidemia is continually being refined, but established predisposing factors including immunosuppression and malignancies, use of broad spectrum antibiotics, and use of indwelling central catheters remain as significant risk factors. The high cost of health care and greater attention to continuous quality improvement will stimulate better and more effective ways of diagnosing and treating candida infections using combined clinical and microbiologic acumen. There is room for optimism as newer antifungal agents with reduced toxicities have impact on therapy of candidal infections. Aggressive development of still more agents and reformulations of older agents continue in earnest. Even greater consolation comes from the increased awareness of lay and medical personnel alike regarding the appropriate and judicious use of antimicrobial agents.     

Replacement of loop II of VP1 of the DA strain with loop II of the GDVII strain of Theiler's murine encephalomyelitis virus alters neurovirulence, viral persistence, and demyelination

Theiler's murine encephalomyelitis viruses, which are murine picornaviruses, can cause central nervous system inflammatory disease. To study the role of loop II in capsid protein VP1, two mutant viruses of strain DA in which DA loop II amino acids were replaced with strain GDVII amino acids were constructed. Infection of mice with the two mutant viruses led to dramatically different patterns of disease.