湛江民航机场白纹伊蚊幼虫季节性消长调查

目的:了解湛江民航机场白纹伊蚊幼虫季节消长情况,为防止登革热等蚊媒传染病传播提供依据。方法:用容器指数法。结果:共捕获白纹伊蚊幼虫536条,平均密度为3条每/勺;季节消长以5月为最高峰(容器指数为30％),9月出现一小高峰(容器指数为21％),最低为8月(容器指数为6％)。每季度均有一个月的空器指数高达或超过20％。一年四季都有白纹伊蚊生长繁殖。结论:湛江民航机场所属范围可能有登革热等蚊媒传染病传播的潜在危险。     

低频振幅联合功能连接对原发性失眠的研究

目的 低频振幅(ALFF)联合功能连接探讨原发性失眠患者脑功能及网络改变.方法 64名原发性失眠患者(患者组)和59名健康对照者(对照组)进行静息态功能磁共振扫描,然后对两组间的ALFF值以及ALFF值差异脑区的功能连接进行独立样本t检验分析.结果 患者组ALFF增高的脑区为右侧颞中回、右侧补充运动区、右侧额上回内侧、...     

江苏省江滩地区感染性钉螺动态观察

目的 掌握江苏省江滩地区感染性钉螺(以下简称阳性钉螺)的现状分布和消长规律，为控制成批急性血吸虫感染(以下简称急感)的发生提供科学依据。方法以县(市、区)为单位，随机抽检5—10个有螺滩，每滩采样5—10个点，每点捕捉钉螺50--100只，然后由专业人员采用解剖镜检法检测钉螺的自然感染情况，同时对查出的阳性钉螺滩块及螺点即时进行药物杀灭。结果 5年共检测沿江有螺滩467个(条块)，捕捉钉螺169 200只，检出阳性螺滩(条块)102个和阳性钉螺433只，覆盖于12个县(市、区)，已占全省沿江县(市、区)的75．0％(12／16)。结论 经连续5年的观察，江滩阳性钉螺面积和阳性钉螺的螺口数呈逐年增长态势，存在着发生成批急感的潜在威胁。因此，加强江滩和通江河道的治理，提高阳性滩地的灭螺覆盖率和灭螺质量以及反复查治江滩散养畜牧的是今后工作的关键。     

An algorithm accounting for plating efficiency in estimating spontaneous mutation rates

An algorithm is described for calculating the probability distribution of the number of mutant colonies arising in a Luria-Delbrück fluctuation experiment subject to a plating efficiency of less than 100%. A table is constructed to facilitate the estimation of spontaneous mutation rates taking into account the plating efficiency.     

The fluctuation in recovery following whiplash injury 7.5-year prospective review

Forty-two patients with a whiplash injury were assessed at the time of injury, after 3 months, 2 years and a mean of 7.5 years. The range of neck movement, pain, its effect on lifestyle, and psychometric testing were determined in each of the patients. Between 2 and 7.5 years, 5 (12%) described improved symptoms, 12 (29%) complained of continuing pain and 14 (33%) reported increased severity of symptoms since the accident. Neck pain was the commonest complaint in 23 (55%) and low back pain in 18 (43%). Radiation of pain was more common in the severely symptomatic patients. There was no significant difference in either the ages or sex of the patients between the symptomatic and asymptomatic groups. Anxiety and depression correlated well with symptom severity. None of the asymptomatic patients revealed any degree of psychological disturbance compared with 30 (77%) in the symptomatic groups. Symptoms largely stabilised within 3 months but there was significant fluctuation in symptom severity between 3 months and 2 years. This suggests that outcome cannot be accurately assessed during this time. In order to effectively manage those most severely affected by whiplash, patients should be identified within the first 12 weeks following injury if the outcome of their injury is to be modified.     

Chaos attractors of ventricular elastance to evaluate cardiac performance

Quantitative evaluation of cardiac function is very important in the clinical application of a ventricular assist device. This article reports a new evaluating method of E max, which is the most reliable parameter to evaluate cardiac function. Fluctuation in the E max time series data was evaluated by the nonlinear mathematical analyzing method including chaos and fractal theory. Experimental goats were anesthetized with halothane inhalation, and left ventricular volume and pressure were measured with other hemodynamic parameters to evaluate E max during various drug administrations. E max was evaluated by two methods. One was the conventional pressure volume loop evaluation and the other was the parameter optimization method without left ventricular volume data. As a result, E max evaluated by the parameter optimization method correlated well with the E max with conventional PV curve. Furthermore, interesting results were obtained. There were rhythmical fluctuations in the E max time series data. By the methodology of Takens, E max time series data was embedded into the phase space and a strange attractor was observed. These results may be important when considering E max evaluation during left ventricular assistance.     

Modifications of the bacterial reverse mutation test reveals mutagenicity of TiO2 nanoparticles and byproducts from a sunscreen TiO2-based nanocomposite

The bacterial reverse mutation test, recommended by the Organization for Economic Co-operation and Development (OECD) to determine genotoxicity of chemical compounds, has been recently used by several authors to investigate nanoparticles. Surprisingly, test results have been negative, whereas in vitro mammalian cell tests often give positive genotoxic responses. In the present study, we used the fluctuation test procedure with the Salmonella typhimurium strains TA97a, TA98, TA100 and TA102 to determine the mutagenic potential of TiO₂ nanoparticles (NP-TiO₂) and showed that, when it is used conventionally, this test is not suitable for nanoparticle genotoxicity assessment. Indeed, the medium used during exposure prevents electrostatic interactions between bacterial cells and nanoparticles, leading to false-negative responses. We showed that a simple pre-exposure of bacteria to NP-TiO₂ in a low ionic strength solution (NaCl 10 mM) at a pH below the nanoparticle isoelectric points (pH 5.5) can strongly improve the accuracy of the test. Thus, based on these improvements, we have demonstrated the genotoxicity of the engineered NP-TiO₂ tested and a NP-TiO₂ byproduct from a sunscreen nanocomposite. It was also shown that strain TA102 is more sensitive than the other strains, suggesting an oxidative stress-mediated mechanism of genotoxicity.     

北京市毛蠓种类分布及日消长调查研究（双翅目：蠓科）

目的了解北京市毛蠓种类及其日消长动态,为蠓科昆虫的生态习性研究提供生态和生物学基础资料。方法采用挥网法。结果发现杜复毛蠓、暗色毛蠓、装饰毛蠓、喜愿毛蠓和饶河毛蠓5个北京新纪录毛蠓;卢沟桥宽带毛蠓的群舞高峰发生在16：00,此时温度25℃,相对湿度68％。结论北京市毛蠓种类丰富,群舞高峰明显。     

磁性附着体对人体重心动摇的影响

目的 磁性附着体作为外来的磁场介入体内,本文就其是否会对身体重心产生影响进行研究。方法 选取10例男性志愿受试者,制作热压He垫并在其上放置三个磁性附着体,观察磁性附着体放入前后身体重心,轨迹动摇的变化情况。结果 发现在磁性附着体放入前后,在睁眼和闭眼情况下,身体重心动摇轨迹的长度。包绕面积和矩形面积以及重心位置都没有发生变化。结论 磁性附着体不会对人体的平衡机能产生明显的影响。     

Fluctuation analysis of patch-clamp or whole-cell recordings containing many single channels

A novel analytical method for characterizing single-channel currents from recordings containing many identical, independent channels is described. The method is based on the assumption that the opening and closing of each single channel contributing to the summed current can be represented as a first-order, discrete-time, binary Markov chain and that the variance of the quiescent channel noise is known. Utilizing the first 3 moments of the record, and its power spectrum, all relevant single-channel parameters can be estimated. This includes the number of channels, the open current amplitude of a single channel, the mean open and closed durations and the probability of a channel being in the open state. In addition, the magnitude of the shot noise resulting from the flux of ions across the membrane can be estimated. Using fictitious multi-channel recordings generated by summing 2-990 independent binary Markov chains together with additive white noise, we have tested the reliability of the method in estimating the statistics of single channels. Finally, we discuss how the technique may be extended to cope with data which has been low-pass filtered, and also suggest further experiments which the technique now makes possible.