Swimming performance is reduced by reflective markers intended for the analysis of swimming kinematics

The present study aimed to clarify whether swimming performance is affected by reflective markers being attached to the swimmer’s body, as is required for a kinematic analysis of swimming. Fourteen well-trained male swimmers (21.1 ± 1.7 yrs) performed maximal 50 m front crawl swimming with (W) and without (WO) 25 reflective markers attached to their skin and swimwear. This number represents the minimum required to estimate the body’s center of mass. Fifty meter swimming time, mid-pool swimming velocity, stroke rate, and stroke length were determined using video analysis. We found swimming time to be 3.9 ± 1.6% longer for W condition. Swimming velocity (3.3 ± 1.8%), stroke rate (1.2 ± 2.0%), and stroke length (2.1 ± 2.7%) were also significantly lower for W condition. To elucidate whether the observed reduction in performance was potentially owing to an additional drag force induced by the reflective markers, measured swimming velocity under W condition was compared to a predicted velocity that was calculated based on swimming velocity obtained under WO condition and an estimate of the additional drag force induced by the reflective markers. The mean prediction error and ICC (2,1) for this analysis of measured and predicted velocities was 0.014 m s⁻¹ and 0.894, respectively. Reducing the drag force term led to a decrease in the degree of agreement between the velocities. Together, these results suggest that the reduction in swimming performance resulted, at least in part, from an additional drag force produced by the reflective markers.     

8种阔叶树种叶片气体交换特征和叶绿素荧光特性比较

在自然条件下,测定了8种阔叶树种叶片的气体交换参数和叶绿素荧光参数并对其进行比较.结果表明,8种阔叶树种紫玉兰、广玉兰、玉兰、美人梅、铁杆梅、腊梅、红碧桃和紫薇的叶片净光合速率（Pn）、蒸腾速率（Tr）、气孔导度（gs）、瞬时水分利用效率（WUE）和潜在水分利用效率（WUEi）的种间差异达极显著水平（p〈0.01）,指示了不同树种间的光合能力及水分利用能力差别较大.8种阔叶树种叶片的初始荧光（Fo）、可变荧光（Fv）、最大荧光（Fm）和PSⅡ电子传递量子效率（ФPSⅡ）的种间差异极为显著（p〈0.01）,PSⅡ最大光能转换效率（Fv/Fm）、可变荧光与初始荧光之比（Fv/Fo）和非光化学猝灭系数（NPQ）的种间差异也达显著水平（p〈0.05）,说明各树种叶片的PSⅡ原初光能转换效率和潜在活性、PSⅡ电子传递量子效率以及PSⅡ的潜在热耗散能力差别较大,而实际光下最大荧光（F′m）和PSⅡ光能捕获效率（F′v/F′m）的种间差异不显著.3种木兰科植物的Pn、Tr、WUE和WUEi平均值均高于3种蔷薇科植物,说明木兰科植物的光合能力较强,对吸收的光能和水分的利用较高.蔷薇科植物的Fv/Fm、Fv/Fo、ФPSⅡ、F′v/F′m和光化学猝灭系数（qp）平均值均高于木兰科植物,而木兰科植物NPQ较高,表明其PSⅡ的潜在热耗散能力较强,可有效地避免过剩光能对光合机构的损伤.研究还表明3种木兰科植物和3种蔷薇科植物之间的叶绿素荧光参数差异不大,说明同一科属植物叶片的光合能力较为相近.相关分析表明,8种阔叶树种叶片的Pn与Tr、Tr与gs、Fv/Fm与Fv/Fo、ФPSⅡ与F′v/F′m、qp与NPQ均呈极显著正相关（p〈0.01）,Pn与gs呈显著正相关（p〈0.05）,而Tr、gs与WUE、WUEi,Pn与ФPSⅡ,ФPSⅡ与NPQ,F′v/F′m 与 qp、NPQ均呈极显著负相关（p〈0.01）.     

A novel approach for estimating growth phases and parameters of bacterial population in batch culture

Traditionally, microbiologists divided bacterial growth in batch cultures into lag, exponential, station-ary and death phases[1], following the Logistic equa-tion that has been applied to the growth of human populations. The growth curves can always be ch…     

Physiological foundation for the differences of long-term water use efficiency among Populus deltoides clones

With randomized complete block design, long-term water use efficiency (WUE_L), photosynthetic parameters (net photosynthetic rate Pn, transpiration rate Tr, stomatal conductance Gs, instantaneous water use efficiency WUE_i, maximum photosynthetic rate P max, light saturation pointLSP, carboxylic efficiency Ce), stomatal properties (frequency, size, superior/inferior stoma amount ratio) and root/shoot ratio of twelve Populus deltoids clones were studied under water stress in a greenhouse. Four water treatments were designed, namely, well-watered condition, slight water stress, moderate water stress, and severe water stress. Although the volumes of irrigated water for different treatments were the same, the irrigation intervals were strictly controlled. The results showed that long-term water use efficiency (WUE_L) differences among tested clones were obvious and became greater with the increase in water stress. J₂, J₆, J₇, J₈, and J₉ were excellent clones with high WUE_L. Stomatal frequency, stomatal size, Gs, Tr, Pn, and root/shoot ratio of J₂et al were moderate, whereas the superior/inferior ratio, P_max, LSP, Ce of J2et al were higher than other clones. The interrelations between WUE_L and the physiological parameters were analyzed. The results revealed that the WUE_L differences were induced by a series of physiological parameters, and clones with higher WUE_L always had strong photosynthetic capacity, higher WUE_i, and optimum root/shoot ratio.     

慢性心力衰竭患者N端脑钠肽前体、脑钠肽与患者心脏超声参数及炎症因子的关系

目的:探讨慢性心力衰竭(CHF)患者N端脑钠肽前体(NT-proBNP)、脑钠肽(BNP)与患者心脏超声参数及炎症因子的关系。方法:选取2015年3月～2018年2月期间我院收治的CHF患者135例为研究组。根据纽约心脏病学协会(NYHA)心功能分级将研究组分为Ⅰ级组26例,Ⅱ级组34例,Ⅲ级组42例,IV级组33例。另选取同期于我院体检的健康志愿者30例为对照组。检测并比较对照组与研究组、不同NYHA心功能分级的血清标志物、炎症因子、心功能超声参数,采用Pearson相关性分析NT-proBNP、BNP与炎症因子、心功能超声参数的相关性。结果:研究组血清BNP、NT-proBNP、白介素-6(IL-6)、肿瘤坏死因子-α(TNF-α)、超敏C反应蛋白(hs-CRP)水平及左心室舒张末期内径(LVEDD)、左心室收缩末期内径(LVESD)均显著高于对照组,左心室射血分数(LVEF)则低于对照组(P0.05)。BNP、NT-proBNP、IL-6、TNF-α、hs-CRP水平及LVEDD、LVESD随心功能分级的升高而升高,LVEF随心功能分级的升高而降低(P0.05)。经Pearson相关性分析显示,CHF患者BNP、NT-proBNP与IL-6、TNF-α、hs-CRP、LVEDD、LVESD呈正相关,而与LVEF呈负相关(P0.05)。结论:血清NT-proBNP、BNP与CHF患者的心脏超声参数及炎症因子密切相关,可考虑将其作为临床诊断CHF的生物学指标。     

Survival and life table parameters of soybean pod borer Maruca vitrata (Geyer) (Lepidoptera: Crambidae) on leguminous crop cultivars

The soybean pod borer, Maruca vitrata is one of the key insect pests of tropical legumes. It damages tender leaf axils, flower buds, flowers and pods by webbing and boring clusters of flowers and pods. In this study, we investigated the survival and life table parameters of M. vitrata on several leguminous crops; soybean (cvs. Daewon, Poongsannamool and Socheongja), azuki bean (cv. Hongeon), mung bean (cv. Sanpo), and cowpea (cv. Jangchae), compared to artificial diet to assess the antibiosis resistance to M. vitrata. The life‐variables of M. vitrata were significantly affected by the tested legume cultivars. None of the larvae fed cowpea cultivar Jangchae survived. The azuki bean cultivar Hongeon and mung bean cultivar Sanpo were found susceptible to M. vitrata, whereas cowpea cultivar Jangchae and soybean cultivar Daewon showed antibiosis resistance to M. vitrata. Further studies should examine the chemicals associated with leguminous crop cultivars and its mechanism to develop a control method against M. vitrata.     

Rice (<i>Oryza sativa</i> L.) Breeding among Hassawi Landrace and Egyptian Genotypes for Stem Borer (<i>Chilo agamemnon</i> Bles.) Resistance and Related Quantitative Traits

Rice stem borer (Chilo agamemnon Bles.) is a primary insect pest of rice and is a major limiting factor to rice production. Breeding for insect-resistant crop varieties has been an economic way of integrated pest management (IPM) as it offers a viable and ecologically acceptable approach. This study was aimed to evaluate rice genotypes for their resistance against rice stem borer. Seven parental genotypes with twenty one F1 crosses were evaluated for genotypic variation in field experiments. Analysis of variance revealed significant differences for the studied traits in almost all crosses and parents. In addition, the mean squares of parents versus their crosses were signifi- cant for stem borer resistance and other associated traits. Moreover, both general combining ability (GCA) and specific combining ability (SCA) variances were highly significant for all characters studied in the F1 generation. Based on GCA, 4 genotypes (Sakha101, Gz6903-3-4-2-1, Gz9577-4-1-1 and Hassawi) exhibited highly significant negative values for stem borer resistance (–0.53, –1.06, –0.18 and –0.49, respectively) indicating they are the best combiners for stem borer resistance. Based on SCA analysis, nine cross combinations showed highly significant negative effects for stem borer resistance. Similarly, the cross Giza178 Hassawi was the best combination with significantly highest value for early maturity. In addition, seven crosses showed highly significant negative SCA for plant height trait. On the other hand, for panicle length, number of primary branches/panicle, panicle weight and 1000-grain weight, seven, four, eight and six crosses showed highly significant positive SCA, respectively. The result further revealed that the non-additive dominance genetic variance was higher than the additive variance for all evaluated traits indicating that non-additive genetic variances have a role in their inheritance. The broad-sense heritability estimates were high for all the studied traits. The stem borer resistance was significantly correlated with panicle weight and 1000-grain weight, which also showed a highly significant correlation with grain yield/plant. Thus these traits can be effectively employed in a breeding program to confer resistance against stem borer infestation in rice. It was further supported by biplot analysis, which clustered these potentially important traits into two quadrants showing their importance in any future breeding program to control stem borer infestation. This study has contributed valuable information for evaluation of genetic diversity in the local rice germplasm and its utilization in futuristic rice genetic improvement programs.     

应用定量微生物风险评估海水浴场人体健康风险

【背景】定量微生物风险评估作为定量评估游泳人群暴露于病原微生物后健康风险的方法,在国外已得到广泛应用,但目前国内的应用处于起步阶段且缺乏所需的游泳人群暴露数据。【目的】收集游泳人群暴露数据,并在海水浴场中进行应用,评估粪大肠菌群作为风险评估指标的可行性。【方法】通过对6个典型海水浴场的水质状况、粪大肠菌群浓度与环境因子的相关性进行分析,并发放调查问卷收集国内游泳人群的暴露数据,进而应用定量微生物风险评估方法,得出各个海水浴场的胃肠道疾病患病风险。【结果】6个海水浴场中粪大肠菌群浓度均与水温、气温及总云量具有显著相关性(P<0.01)。位于南方的海水浴场粪便污染情况较北方严重,粪大肠菌群浓度第95百分位数远高于国内“差”类水质标准的阈值。儿童、成年男性、成年女性单次沐浴事件吞下海水的体积分别为35.1 mL (95%置信区间为32.4-37.8,α=0.578,β=0.016),45.0 mL (95%置信区间为31.1-59.3,α=0.532,β=0.012),35.7 mL (95%置信区间为29.7-41.8,α=0.753,β=0.032)。6个海水浴场患胃肠道疾病的风险...     

花生对非繁殖期雌性黑线仓鼠细胞免疫和血液指标的影响

食物的数量和质量是影响动物免疫功能的重要因素。野生动物在选择食物时是否会优先选择有利于其健康的食物？为解决该问题,我们以黑线仓鼠(Cricetulus barabensis)为研究对象,通过饲喂其喜食食物花生(Arachis hypogaea),然后检测反映健康状况的细胞免疫能力和血液指标。将30只非繁殖期成年雌性黑线仓鼠随机分为正常饲料组(normal fodder group,NF,n=10)、花生加饲料组(normal fodder plus peanuts group,NP,n=10)和花生组(Peanut,n=10),饲喂39 d后检测各项指标。结果发现Peanut组的体重增加,NP和Peanut组的摄食量降低。NP组注射植物血球凝集素(Phytohaemagglutinin,PHA)后12 h的PHA反应显著高于NF组。3组间白细胞数和淋巴细胞数在统计学上没有显著差异,但NP和Peanut组白细胞数比NF组分别高22.9%和25.0%,淋巴细胞数分别高15.0%和22.5%。NP和Peanut组红细胞数和红细胞压积显著高于NF组,而Peanut组血小板数显著高于NF和NP组。这些结果表明饲喂花生能增强黑线仓鼠的细胞免疫能力、输氧能力和凝血功能,这可能是其喜食花生的生理原因。     

马来酸曲美布汀联合莫沙必利对功能性消化不良患者胃电图参数、肠道菌群和血清NPSR-1、CGRP、MTL、GAS的影响

摘要 目的：观察马来酸曲美布汀联合莫沙必利对功能性消化不良（FD）患者胃电图参数、肠道菌群和血清神经肽S受体-1（NPSR-1）、降钙素基因相关肽（CGRP）、胃动素(MTL)、胃泌素(GAS)的影响。方法：选取2019年8月~2021年6月期间我院收治的FD患者100例,根据信封抽签法分为对照组（莫沙必利治疗,n=50）和观察组（马来酸曲美布汀联合莫沙必利治疗,n=50）。对比两组疗效、胃电图参数、肠道菌群变化情况和血清NPSR-1、CGRP、MTL、GAS水平,记录两组不良反应发生率。结果：观察组的临床总有效率高于对照组（P<0.05）。治疗后,两组空腹及餐后正常慢波百分比均较治疗前升高,胃电频率、胃电紊乱节律百分比均较治疗前下降,且观察组的变化幅度更大（P<0.05）。治疗后,两组肠杆菌、肠球菌、酵母菌数量较治疗前下降,且观察组的下降幅度更明显（P<0.05）。治疗后,两组血清CGRP水平较治疗前下降,NPSR-1、MTL、GAS水平较治疗前升高,且观察组的变化幅度更大（P<0.05）。两组不良反应发生率组间对比差异无统计学意义（P>0.05）。结论：马来酸曲美布汀联合莫沙必利治疗FD患者,可有效改善胃电图参数和肠道菌群分布,调节其血清NPSR-1、CGRP、MTL、GAS水平,安全有效。