Unilateral congenital short femur: A case report

A case of congenital short femur in an otherwise healthy infant is described. Antenatal sonographic diagnosis was made at 26 weeks of gestation. The left femur was shorter than the right (ratio 0·82–0·85). In this case, the occurrence of congenital short femur was sporadic. The diagnosis was confirmed after delivery. This case illustrates the importance of ultrasound as an early detector of certain congenital anomalies and as a useful tool in their follow-up.     

Sedimentation of short cylindrical pollutants with mechanical contacts

Lattice Boltzmann method and elastic particle collision model were used to investigate the sedimentation of short cylindrical pollutant particles with mechanical contacts for varying bulk number density ε and terminal Reynolds number ReT. The corresponding experiments were performed as a comparison. The clusters of pollutant particles with an inverted “T” structure were observed, the pollutant particles for high ε and large ReT scattered wider than that for low ε and small ReT. The sedimentation velocities increased suddenly at the initial stage, then decreased drastically, after that swayed around and approached to a steady value. The time to steady state did not depend on ε and ReT. The effect of particle interactions was to hinder the average sedimentation velocity, and hindrance was directly proportional to ε. The orientation distributions of pollutant particles depended on ReT and ε, especially on the former. Both the standard deviations of vertical and horizontal velocity, the former was larger than the latter, were nearly independent on ε and ReT.     

Glycogen with short average chain length enhances bacterial durability

Glycogen is conventionally viewed as an energy reserve that can be rapidly mobilized for ATP production in higher organisms. However, several studies have noted that glycogen with short average chain length in some bacteria is degraded very slowly. In addition, slow utilization of glycogen is correlated with bacterial viability, that is, the slower the glycogen breakdown rate, the longer the bacterial survival time in the external environment under starvation conditions. We call that a durable energy storage mechanism (DESM). In this review, evidence from microbiology, biochemistry, and molecular biology will be assembled to support the hypothesis of glycogen as a durable energy storage compound. One method for testing the DESM hypothesis is proposed.     

The controlled short circuit GMAW process: A tutorial

The paper reviews the principles, benefits and limitations of the conventional short circuit transfer mode in GMA welding before describing the development and benefits of the controlled short circuit approach. Various options are described and an attempt is made to categorize the current commercial systems.     

Dry deposition of fine aerosol to a short grass surface

Soluble sulphate has been used as a marker for fine aerosols and dry deposition has been estimated using a profile technique. The effects of coarse particles were excluded from the measurements by passage of the sampled air through Nuclepore polycarbonate prefilters, resulting in a 2μm upper cut-off. A total of 99 separate experiments were conducted between June 1988 and June 1989 and 50 acceptable profiles remained after the application of a rigorous quality control procedure. The mean deposition velocity was found to be equal to 0.1 ± 0.03 (standard error) cm s⁻¹. There were no observed dependences of deposition velocity on either atmospheric stability or friction velocity within the range of conditions encountered.     

不同供氧策略对SBBR反应器实现短程硝化厌氧氨氧化的影响分析

以氨氮浓度较高的垃圾渗滤液为处理对象,分析研究了不同供氧策略对SBBR反应器实现短程硝化厌氧氨氧化的影响.在4种不同供氧策略(a、b、c和d的总供氧时间分别为16h、12h、12h和8h;好氧/厌氧交替频率分另U为4h/2h、3h/3h、2h/2h和2h/4h)下同步启动反应器,保持各反应器内环境温度为(30.0±4-0.5)℃,并控制曝气阶段溶解氧(DO)浓度为(1.2±0.1)mg·L-1.实验结果表明,反应器内的微生物经过124d的驯化和增殖,具有一定的脱氮能力,但是效果不同,其中,采用总供氧时问为12h,好厌氧交替频率为2h/2h供氧策略的反应器c效果最好,氨氮去除率达到96.6%左右,而且抗氨氮冲击负荷的能力最强,最大的氨氮容积负荷为0.186 g·(L·d)-1;在曝气阶段由于DO浓度的限制,亚硝酸盐出现积累;缺氧阶段,由于厌氧氨氧化细菌和反硝化细菌的协同作用,亚硝酸盐氮和氨氮同时被去除,且没有硝酸盐的积累.从4个反应器和渗滤液原水中提取细菌总DNA,通过PCR-DGGE技术获得DGGE图谱.分析图谱中各泳道的条带数目和条带亮度、各泳道间的相似性系数C,值,结果表明,不同供氧策略对反应器内的细菌多样性和种群结构产生了较大影响.     

碳源类型对超短泥龄活性污泥系统运行影响研究

由于可以同时实现污水中碳磷的快速分离,超短泥龄活性污泥系统在降低能耗与资源回收方面受到人们的广泛关注.本研究对不同 进水碳源（乙酸钠、丙酸钠、葡萄糖、生活污水）条件下超短泥龄活性污泥系统污泥性质、碳磷分离规律与分离机制、微生物动力学参数等进行了研究.结果表明,与生活污水相比,由单一碳源所培养超短泥龄活性污泥浓度较低,活性较高,但乙酸钠与丙酸钠培养活性污泥处于微膨胀状态.不同碳源培养系统中COD的去除性能并无明显差异（p>0.05）,并且由于生活污水中含有悬浮物,COD去除性能弱于单一碳源培养系统.不同碳源培养系统中磷酸盐的去除性能存在较大差异,乙酸钠与丙酸钠基本依靠生物效应除磷,但生物效应无法实现高效除磷,葡萄糖与 生活污水培养系统均同时依靠生物效应与EPS吸附效应除磷,不同碳源培养系统除磷效率排序为：葡萄糖>生活污水>丙酸钠>乙酸钠.研究同时发现,碳源分子量越小,培养系统中活性污泥生物活性越高,异养菌生长与衰减系数越高.     

短期OTC 处理对鹅绒委陵菜健康影响的研究初报

利用开顶箱（Open Top Chambers, OTC）模拟增温的方法,研究了短期变暖对鹅绒委陵 菜健康的影响。结果表明,短期变暖后降低了鹅绒委陵菜的萌蘖株死亡、增加了单位长度匍匐茎 的萌蘖株数目和其死亡率,同时叶片数目、高度和健康率比对照增加,匍匐茎长度和匍匐茎上萌 蘖株数目比对照减少,同时所有表征指标中只有萌蘖死亡率和叶片高度比对照有显著变化 （p ＜ 0.05）。     

A simple electrophoretic procedure for fetal diagnosis of β-thalassaemia due to short deletions

This study describes three couples a t risk for homozygous β-thalassaemia in which one of the partners carried a short deletion β-thalassaemia defect. Detection of short deletions in trophoblast DNA was accomplished by the very simple procedure of non-denaturing polyacrylamide gel electrophoresis. This method may be applied to detect β-thalassaemia mutations due to deletion or addition of more than two nucleotides.     

麻痹性贝毒在栉孔扇贝体内短期的累积与排出过程

初步研究了微小亚历山大藻Alexandrium minutum产生的麻痹性贝毒(paralytic shellfish poisoning,PSP)在栉孔扇贝Chlamys farreri体内短期累积、转化与排出的规律。结果表明,在累积实验阶段,栉孔扇贝内脏、肌肉及生殖腺中的PSP毒素含量均随实验时间的延长而逐渐增加,累积20 h后内脏的毒性达21.56μgSTXeq/100 g,累积速率为1.05μgSTXeq/100 g/h。内脏是毒素累积的主要部位,含量占贝体内PSP毒素总量的89.5%,累积率为6.4%,远远高于肌肉、生殖腺。经过30 h的排出阶段,扇贝总毒性减少到15.05μgSTX eq/100 g,排出速率为0.22μgSTXeq/100 g.h,仅为累积速率的1/5。     

Anaerobic treatment of source-separated domestic bio-wastes with an improved upflow solid reactor at a short HRT

Anaerobic treatment is the core technology for resource and energy recovery from source-separated domestic bio-wastes. The higher efficiency of an improved upflow solid reactor(IUSR) designed in this study was demonstrated in the treatment of concentrated black water and kitchen waste. The highest methane production of 48 L/person/day was achieved at the hydraulic retention time(HRT) of 7 days, while the other measures of performance at the HRT of 8.3 days were better than at the HRT of 7 or 10 days, achieving a methane production of 43 L/person/day, removal of total chemical oxygen demand(TCOD)of 89%, removal of soluble chemical oxygen demand(SCOD) of 92%, and conversion of chemical oxygen demand(COD) to methane of 71%. It is not recommended to decrease HRT lower than 7 days due to the instability of the initial period. The concentrations of volatile fatty acids(VFAs) in the IUSR were less than 10 mg/L, indicating that the anaerobic process was stable. Sludge bed development showed that sludge bed with high microbial activity was formed in the bottom and that the precipitation zone of effluents formed should preferably occupy 30% of the height of the IUSR. The effluents of the IUSR could be used for irrigation in agriculture in combination with a settling tank accompanied by disinfection to remove solids and pathogens.     

小分子有机碳源对滴滴涕污染沉积物生物修复作用的基础研究

考察了辽河沉积物p,p'-DDT在无外加碳源和外加乳酸钠或丙酸钠情况下的缺氧生的降解行为，降解过程中体系的pH变化，并测定了p,p'-DDT的主要缺氧降解产物及其浓度变化，结果表现，p,p'-DDT的缺氧脱氯行为符合准一级反应动力学，无外加碳源，DDT的缺氧脱氯降解有近一个月的滞后期，降解速率为k（无碳源）＝0.0082d^-1，而外加碳源物质，大大缩短了DDT缺氧脱氯降解的滞后，降解速率分别为k(乳酸钠）＝0.0917d^-1,k(丙酸钠）＝0.1023d^-1，而且，p,p'-DDT的缺氧还原脱氯行为主要发生在体系中pH上升的阶段，p-p'-DDT缺氧生物降解的主要产物是p,p'-DDD，并有少量的p,p'-DDE产生；p,p'-DDD主要发生在体系中pH上升的阶段，p,p'-DDT缺氧生物降解的主要产物是p,p'-DDD，并有少量的p,p'-DDE产生，p,p'-DDD在后期有降解。