Evaluation and standardization of polymerized ragweed extracts by chromatography,radioimmunoassay inhibition,and end point cutaneous titration

The standardization procedures for polymerized ragweed (PRW) must evaluate activity of PRW with assessments that differ from those used for standard unmodified extracts. This is because PRW allergens are different from conventional ragweed extracts in that they are much greater in average molecular weight and much lower in allergenicity for equivalent immunogenicity. We have evaluated seven samples of PRW for three parameters: allergenicity as determined by cutaneous end point titration, molecular weight distribution as determined by Sephadex G-200 chromatography, and availability of antigen E (AgE) determinants as measured by the ability of an extract to inhibit AgE binding to antibody by using a modification of the Farr technique. The skin test titers and molecular weight profiles provide information as to the safety of a PRW preparation and antigen-binding inhibitory activity gives information about allergenicity and immunogenicity. Appropriate limits may be set for each of these parameters to standardize PRW for clinical use.     

The relationship between muscle kinetic parameters and kinematic variables in a complex movement

Summary Kinematic variables of the vertical jump (jumping height, jump phase durations and joint angles) were measured on 39 male physical education students. In addition, kinetic parameters of the hip and knee extensors, and of the plantar flexors (maxima voluntary force and its rate of development) were recorded on the same subjects, in isometric conditions. The results demonstrated significant positive correlations between kinetic parameters of the active muscle groups and jumping height (r=0.217−0.464). The dominant effect on these correlations was due to the knee extensors. Correlations between these parameters and the duration of the jump phases were much weaker. Correlation coefficients between kinetic parameters and limb angles in the lowest body position showed that fast force production in one muscle group was related to a significant decrease in the joint angles of distant body segments. Multiple correlation coefficients between leg extensor parameters and kinematic variables (ranging between 0.256 for the duration of the counter-movement phase and 0.616 for jump height) suggested that kinetic parameters could explain more than a quarter of the variability of this complex human movement. Therefore, the conclusion was drawn that an extended set of measurements of the relevant musculo-skeletal system parameters could predict a considerable amount of the variability of human movement. However, high correlation coefficients between the same kinetic parameters of different muscle groups suggest that not all active muscle groups have to be included in the measurements.     

Publication bias in reproductive research

Publication bias is defined as any tendency on the part of investigators or editors to fail to publish study results on the basis of the direction or strength of the findings. This may lead to overestimation of treatment effects in published work. Inappropriate decisions about patient management may result. We investigated what proportion of abstracts at the European Society of Human Reproduction and Embryology (ESHRE) annual meeting eventually reached full publication, what was the time to publication, and which factors might have affected publication. Among the 2691 abstracts of six ESHRE annual meetings, 151 (5.6%) reporting randomized controlled trials (RCT) were identified. Comprehensive searches of electronic databases and handsearching of the two major journals in the field yielded 79 full publications pertaining to these abstracts. Kaplan-Meier analysis estimated 56% of RCT abstracts to be eventually published in full, the median time to publication being 32.5 months. Positive outcome (i.e. significant results) did not affect the publication rate, and neither did sample size, the subject category, or the native language (English/non-English) of the country of origin. Oral presentations resulted in eventual full publication significantly more frequently (69%) than posters (42%). It is concluded that a considerable publication deficit, but not a publication bias, exists for RCT in reproductive research.     

一种平板流动腔重力灌流系统的力学分析

本文分析了一种采用重力灌流的平板流动腔灌流系统，并根据实验结果确定出相应的阻力系数，获得平板流动腔剪应力、雷诺数以及入口长度与流体重力灌流高度的关系。     

Evaluation of Body Composition,Physical Activity,and Food Intake in Patients with Inborn Errors of Intermediary Metabolism

Children with inborn errors of intermediary metabolism (IEiM) must follow special diets that restrict their intake of essential nutrients and may compromise normal growth and development. We evaluated body composition, bone mineral density, physical activity, and food intake in IEiM patients undergoing dietary treatment. IEiM patients (n = 99) aged 5–19 years and healthy age- and sex-matched controls (n = 98) were recruited and underwent dual-energy X-ray absorptiometry to evaluate anthropometric characteristics and body composition. Data on food intake and physical activity were also collected using validated questionnaires. The height z-score was significantly lower in IEiM patients than controls (−0.28 vs. 0.15; p = 0.008), particularly in those with carbohydrate and amino acid metabolism disorders. Significant differences in adiposity were observed between patients and controls for the waist circumference z-score (−0.08 vs. −0.58; p = 0.005), but not the body mass index z-score (0.56 vs. 0.42; p = 0.279). IEiM patients had a significantly lower total bone mineral density (BMD) than controls (0.89 vs. 1.6; p = 0.001) and a higher risk of osteopenia (z-score < −2, 33.3% vs. 20.4%) and osteoporosis (z-score < −2.5, 7.1% vs. 0%), but none presented fractures. There was a significant positive correlation between natural protein intake and BMD. Our results indicate that patients with IEiM undergoing dietary treatment, especially those with amino acid and carbohydrate metabolism disorders, present alterations in body composition, including a reduced height, a tendency towards overweight and obesity, and a reduced BMD.     

父母身高对7岁以下儿童身高影响效应的研究

目的 分析父母身高对7岁以下儿童身高的影响效应,为个体儿童生长评估提供参考依据。方法 以“2015年中国九市7岁以下儿童体格发育调查”中父母身高信息完整的161 297名儿童为分析对象,参照中国儿童身高标准计算儿童身高、父亲身高、母亲身高和父母身高中值的Z分值,采用Spearman方法分析儿童身高与父身高、母身高、父母身高中值的相关性,并按父母身高分组,比较各组儿童身高的差异。 结果 1)儿童身高与父身高、母身高和父母身高中值正相关(r=0.13~0.42,P<0.05),且与父母身高中值的相关系数最高;2)按父母身高中值分为矮身材、偏矮、中等偏下、中等偏上、较高、高身材6组,各组儿童平均身高依次递增,父母矮身材组儿童身高比父母高身材组低1.9~14.7 cm,年龄越大差值越大;3)父母身高偏矮组子女身高第3百分位(P₃)比中国儿童身高标准P₃低0.6~4.8 cm,而父母较高身材组P₃则比身高标准P₃高0.6~4.7 cm;4)父母矮身材、偏矮、中等偏下、中等偏上、较高和高身材组的儿童身高Z分值与父母身高中值Z分值差值依次为1.27±0.99、0.61±0.92、0.18±0.89、-0.19±0.90、-0.61±0.93、-1.17±0.92。结论 7岁以下儿童身高与父母身高正相关;矮身材父母的子女身高明显低于高身材父母子女;矮身材父母子女身高高于家庭遗传身高;个体儿童身高评估和解释时,不可忽视父母身高的影响作用。     

西昌市城区3~14岁儿童身高状况分析

目的 分析西昌市城区儿童身高的特点,为当地儿童健康发展提供参考。方法 2018年4-5月采用分层整群抽样法以西昌市城区19所学校3~14岁儿童作为研究对象。按照《中国儿童生长标准与生长曲线》的要求,统一测量儿童身高,并使用SPSS22.0软件进行数据分析。结果 西昌市城区的儿童中汉族男生3~6岁及9~11岁、彝族男生3~7岁及10~11岁、汉族女生3~7岁及9~10岁、彝族女生3~10岁的身高均高于全国标准(P<0.05);学龄前期男生汉族儿童身高高于彝族(P<0.05);在学龄期与青春期彝汉两个民族身高差异无统计学意义(P>0.05);男生身高在各年龄段均高于女生身高(P<0.05)。结论 西昌市儿童身高普遍高于全国标准身高,家长应重视身高在儿童生长发育中的作用。     

广州市海珠区3~12岁儿童身高调查及影响因素分析

目的:了解广州市海珠区儿童身高发育情况,分析其影响因素。方法:随机抽取海珠区904名3~12岁儿童进行体格测量,对家长进行问卷调查,获得儿童身高及其影响因素的相关数据。结果:3~5岁组男、女童,6~岁组男童,7~8岁组男、女童,9~岁组男童的身高均值均低于全国水平(P<0.05)。当前身高低于遗传身高的儿童占21.6%;与遗传身高一致占65%;高于遗传身高的占13.4%。母亲身高,体型是否肥胖,经常吃钙片、喝牛奶,慢性疾病史,每天运动时间为身高的影响因素(P<0.05)。结论:广州市海珠区儿童身高发育的整体水平较低,大部分儿童没有发挥身高的生长潜能,应重视环境因素对身高的影响,采取相应干预措施,促进儿童身高增长。     

大型养路机械低温维修超长无缝线路对轨道的影响

运用轨道的有限单元模型,采用荷载增量法,计算了低温条件下大型养路机械维修超长无缝线路对钢轨应力和锁定轨温的影响。计算结果表明,大型机械在一次性起道时会对钢轨产生较大的应力,建议一次性起道量不超过40mm。     

The effects of d-cycloserine and MK-801 on the performance of rats in two spatial learning and memory tasks

The present study was undertaken to investigate the effects of modulation of the (NMDA) receptor on learning and memory. Thus, the performance of rats treated with d-cycloserine, a partial agonist at the glycine recognition site of the NMDA receptor complex, and MK-801, a noncompetitive NMDA receptor antagonist, either alone or concurrently were assessed in radial arm maze and water maze tasks. Administration of MK-801 (0.1 mg/kg, i.p.) impaired acquisition in the water maze (increased escape latency and distance) and working memory in the radial arm maze (increased re-entries) in rats. Moreover, in the radial arm maze, MK-801 disrupted locomotion (increased latencies and decreased arm entries per minute) and impaired the acquisition of reference memory (increased number of errors) performance of rats. d-Cycloserine (0.03, 0.3, 1.0, 3.0, 10 mg/kg, i.p.) had no effects on acquisition or memory performance of control or MK-801-treated rats in either of these tasks. However, d-cycloserine (0.03, 0.3, 3.0 mg/kg) reversed the MK-801-induced disruption in locomotion. Furthermore, 3.0 mg/kg d-cycloserine increased behavioral activity and also decreased the time needed to complete the task in control animals. To conclude, our results suggest that the consequences of NMDA receptor modulation on learning and memory processes and sensorimotor functions may be functionally different or have distinct anatomical locations.