粉末活性炭吸附强化长距离输水管道反应器净水效能实验研究

模拟实际原水输水管道,构建了长距离管道生物化学反应器,研究了粉末活性炭对管道中污染物的强化去除作用.结果表明:有机污染物的去除效率随粉末活性炭投加量的增加而提高;当反应时间为8 h,粉末活性炭投加量为17 mg/L时,COD_(Mn),TOC,DOC和UV254的去除率分别达到51.2%,45.9%,56.5%和70.6%,分别比未加粉末活性炭时提高了34.5%,34.8%,42.1%和57.0%;而粉末活性炭对藻类和氨氮的去除效果不明显.同时,微囊藻毒素-LR、六氯苯和邻苯二甲酸酯类物质的去除率分别达到61.1%,42.1%和49.0%,提高了49.3%,31.4%和31.2%.粉末活性炭能够有效抑制消毒副产物的生成.因此,针对污染较严重的水源水或遇到突发污染事故时,向管道内投加粉末活性炭能有效促进污染物的去除.

The relationship between steeplechase hurdle economy, mechanics, and performance

Background： Research surrounding the steeplechase is scarce, with most research focusing primarily on how biomechanical factors relate to maintaining running speed while crossing barriers. One area that has not been well explored is the relationship between biomechanical factors and hurdling economy. The purpose of this study was to investigate how pel：formance times and biomechanical variables relate to hurdling economy during the steeplechase. Methods： This was accomplished by measuring running economy of collegiate and professional steeplechasers while rmming with and without hurdles. Biomechanical measures of approach velocity, takeoff distance, clearance height, and lead knee extension while hurdling, as well as steeplechase performance times were correlated to a ratio of running economy with and without hurdles. Results： While oxygen uptake was 2.6% greater for the laps requiring five barriers, there was no correlation between steeplechase performance time and the ratio of running economy during the hurdle and non-hurdle laps. Results also indicated no correlation between the aforementioned biomechanical variables and ratio of running economy during the hurdle and non-hurdle laps. Conclusion： Increasing approach velocity did not negatively affect running economy. Increased approach velocity is a benefit for maintenance of race pace, but does not hurt economy of movement.

山东砣矶岛大口遗址人类颅骨测量性状研究

本文针对山东烟台砣矶岛大口遗址1982年发掘出土的人骨标本进行了颅骨测量与分析。基于颅骨测量性状将其与我国境内先秦时期的6个对比组、山东地区新石器时代的9个对比组人群进行生物距离系数的计算,结果表明:大口遗址第一文化期古代居民颅面形态近似先秦时期古华北类型,与山东地区丁公、呈子组等龙山文化时期古代居民较为接近,与本文古DNA分析结果基本相符合。此外,本文还对大口遗址古代居民的人群构成以及龙山文化时期山东先民的颅面形态特征进行了初步探讨。

Kin Interactions of Arabidopsis Based on the Integrated Performance of Plants

Mechanisms of kin selection have been studied to explain how siblings grow together, but the findings remain controversial. This can be ascribed to the use of single indicators without considering other factors. Three ecotypes of Arabidopsis were used to examine kin responses of siblings growing together. Plant traits of leaves, plant shape, reproductive activity, and roots were investigated. We found that Arabidopsis recognized their kin neighbors, showed selective responses to distinct plant traits among ecotypes, and modes of responses were dependent on neighbor＇s growing distance. If single traits were used to judge kin response performance, the results were chaotic. However, by developing and studying an integrated performance value based on multiple traits, we determined that Ler showed similar integrated performances at all planting distances, while the integrated performance of Col was ranked mainly as medium distancedistance small distance large distance, which suggested kin cooperation. However, in comparison to medium and small distances, at which performance was consistent with kin recognition, we found that at large distance, strangers of Ws performed better than kin plants, which suggested competition. Thus, we conclude that kin recognition could be affected by plant competition conditions that are the result of growing distance, and that the integrated performance of individuals was more suitable to evaluate kin interactions of plant species.

电缆细菌及其介导的生电硫氧化(e-SO_(x))过程研究进展

在自然环境中,微生物参与的硫化物氧化过程是地球硫元素循环的重要组成部分,然而在多数情况下,硫化物形成于海滨等沉积物下层,而氧气等电子受体位于表层,微生物如何解决其所需的电子供体和受体不在同一空间位置的问题尚不清楚.近期研究发现,电缆细菌通过生电硫氧化(electrogenic sulfur oxidation,e-SO_(x))过程将空间分离的硫氧化反应和氧气还原反应耦合起来,完美地解决了上述问题.本文总结近10年有关电缆细菌及其介导的生电硫氧化过程的研究进展,主要包括电缆细菌生存环境、生电硫氧化生态学意义、电缆细菌的鉴定与分类、生理特征、导电结构和机制等方面.发现普遍存在于海滨沉积物、淡水沉积物、水生植物根际等环境的生电硫氧化过程可以显著影响硫、铁、碳、钙、氮、磷等元素的循环,解除硫化物毒性,强化有机污染物降解.目前已鉴定出的所有电缆细菌均属于Candidatus Electrothrix属或Candidatus Electronema属.电缆细菌通过嵌入细胞膜的高导电纤维传导电子,而且已经进化出高度故障安全的内部导电网络.建议今后继续开展电缆细菌的遗传和代谢多样性、导电结构、多细胞之间能量分配机制以及导电纤维的仿生学应用开发等方面研究,为将来应用于生物能源、生物电子和生物修复等领域提供理论和思路.

Human activity affects the perception of risk by mule deer

Human activity has been shown to influence how animals assess the risk of predation, but we know little about the spatial scale of such impacts. We quantified how vigilance and flight behavior in mule deer Odocoileus hemionus varied with distance from an area of concentrated human activity--a subalpine field station. An observer walked trails at various distances away from the station looking for deer. Upon encounter, the observer walked toward the focal animal and noted the distance at which it alerted and directed its attention to the approaching human （Alert Distance; AD）, and the distance at which it fled （Flight Initiation Distance;. FID）. AD and FID both increased nonlinearly with distance from the center of the field station, reaching pla- teaus around 250 m and 750 m, respectively. Deer also tended to flee by stotting or running, rather than by walking, when far from the station but they walked away when near the station. These results indicate that deer perceive lower risk near a focused area of human activity, and that vigilance and flight behaviors respond on somewhat different spatial scales. The concept of a spatial ＂human footprint＂ on behavior may be useful for understanding how human activities affect wildlife

Nutrient Composition and Distance from Point Placement to the Plant Affect Rice Growth

Point placement of urea is an efficient technology to improve urea use efficiency in transplanted rice(Oryza sativa L.), but it is largely unknown how nutrient composition in the point placement and the distance from placement site to the plant influence rice root distribution and growth, nutrient uptake, and rice grain yield. A controlled greenhouse experiment was conducted using both N-and P-deficient soil with point placement of N only or N and P together(N + P) at a distance close to or far from the plant,in comparison to an N-spilt application and a no-N control. Both nutrient composition and distance significantly affected rice root growth. Compared with the N point placement, the N + P point placement led to smaller root length and mass densities, higher specific root length(SRL) around the placement site, smaller root system, higher straw mass and grain yield, and higher N and P uptake. The difference between the N + P and N point placements was greater when close to the plant than when far from the plant. It is suggested that higher SRL around the placement site is essential for improving nutrient uptake and rice grain yield, and simultaneous point placement of N and P has a synergistic effect on rice growth.

On the necessity of an integrative approach to understand protein structural dynamics

Proteins are dynamic,fluctuating between multiple conformational states.Protein dynamics,spanning orders of magnitude in time and space,allow proteins to perform specific functions.Moreover,under certain conditions,proteins can morph into a different set of conformations.Thus,a complete understanding of protein structural dynamics can provide mechanistic insights into protein function.Here,we review the latest developments in methods used to determine protein ensemble structures and to characterize protein dynamics.Techniques including X-ray crystallography,cryogenic electron microscopy,and small angle scattering can provide structural information on specific conformational states or on the averaged shape of the protein,whereas techniques including nuclear magnetic resonance,fluorescence resonance energy transfer(FRET),and chemical cross-linking coupled with mass spectrometry provide information on the fluctuation of the distances between protein domains,residues,and atoms for the multiple conformational states of the protein.In particular,FRET measurements at the single-molecule level allow rapid resolution of protein conformational states,where information is otherwise obscured in bulk measurements.Taken together,the different techniques complement each other and their integrated use can offer a clear picture of protein structure and dynamics.

RNA-protein distance patterns in ribosomes reveal the mechanism of translational attenuation

Elucidating protein translational regulation is crucial for understanding cellular function and drug development.A key molecule in protein translation is ribosome,which is a super-molecular complex extensively studied for more than a half century.The structure and dynamics of ribosome complexes were resolved recently thanks to the development of X-ray crystallography,Cryo-EM,and single molecule biophysics.Current studies of the ribosome have shown multiple functional states,each with a unique conformation.In this study,we analyzed the RNA-protein distances of ribosome(2.5 MDa)complexes and compared these changes among different ribosome complexes.We found that the RNA-protein distance is significantly correlated with the ribosomal functional state.Thus,the analysis of RNA-protein binding distances at important functional sites can distinguish ribosomal functional states and help understand ribosome functions.In particular,the mechanism of translational attenuation by nascent peptides and antibiotics was revealed by the conformational changes of local functional sites.

Toward molecular models of proton pumping:Challenges,methods and relevant applications

Motivated by several long-lasting mechanistic questions for biomolecular proton pumps,we have engaged in developing hybrid quantum mechanical/molecular mechanical(QM/MM) methods that allow an efficient and reliable description of long-range proton transport in transmembrane proteins.In this review,we briefly discuss several relevant issues:the need to develop a "multi-scale" generalized solvent boundary potential(GSBP) for the analysis of chemical events in large trans-membrane proteins,approaches to validate such a protocol,and the importance of improving the flexibility of QM/MM Hamiltonian.Several recent studies of model and realistic protein systems are also discussed to help put the discussions into context.Collectively,these studies suggest that the QM/MM-GSBP framework based on an approximate density functional theory(SCC-DFTB) as QM holds the promise to strike the proper balance between computational efficiency,accuracy and generality.With additional improvements in the methodology and recent developments by others,especially powerful sampling techniques,this "multi-scale" framework will be able to help unlock the secrets of proton pumps and other biomolecular machines.

Fast vectorized distance matrix computation for multiple sequence alignment on multi-cores

Although high quality multiple sequence alignment is an essential task in bioinforma- tics, it becomes a big dilemma nowadays due to the gigantic explosion in the amount of molecular data. The most consuming time and space phase is the distance matrix computation. This paper addresses this issue by proposing a vectorized parallel method that accomplishes the huge number of similarity comparisons faster in less space. Per- formance tests on real biological datasets using core-iT show superior results in terms of time and space.