关键词： marine algae   damaged coral colonies   competition   recovery  

摘要： Natural and anthropogenic catastrophes in the last decades of the 20th century and at the beginning of the new century have evoked significant changes in the biological diversity of coral reefs, viz., the mortality of hermatypic scleractinian corals that are replaced by communities of marine algae and seaweeds. In this connection, the study of the dynamics of algal colonization of a newly formed substratum and competition for the substratum between hermatypic corals and algae is of topical interest. This paper describes the results of investigations conducted in 2003 at the Sesoko Marine Biological Station of Ryukyu University (Okinawa, Japan). Colonies of the massive scleractinian coral Porites lutea were sampled from a fringing reef of Sesoko Island. Damages were inflicted on the upper portions of the colonies, the damaged coral fragments were placed in aquaria and maintained for six months under different light intensities in the absence of herbivorous and corallivorous animals. The experiments showed that under bright (70-90% of incident photosynthetically active radiation, PAR(0)) and under moderate light (20-30% of PAR(0)), the damaged parts of colonies of about 25 cm(2) were overgrown by newly formed polyps within six months. Under dim light (2-5% of PAR(0)), this period was not sufficient for recovery from lesions. During the first month, the recovery rate of colonies was the highest and depended on the physiological state of the corals and light intensity: in bright and moderate light it was two times and more higher than under low light. During the subsequent months, the recovery rate was significantly lower and depended mainly on the degree of overgrowth of dead portions with algae and on their species composition. Under bright and moderate light, algal colonization of damaged colonies started with the settling of colonial and filamentous diatoms, cyanobacteria and green algae, followed by the formation of the algal turf community. Communities of red calc

关键词： Peptides and proteins   Mixtures   Differential scanning calorimetry   Materials   Stability  

摘要： Co-milling of various carbamazepine (CBZ) polymorphic forms (form I, III and dihydate) with nicotinamide (NIC) was performed in this Study to investigate the formation kinetics of carbamazepine-nicotinamide cocrystals (CBZ-NIC) and to evaluate their physical stability. Milling was carried out at room temperature using an oscillatory ball mill at a 1:1 molar ratio of CBZ and NIC for various times up to 60 min. A freshly prepared sample was used for each milling. In the stability study, the milled samples (4, 10, 15, and 30 min) were stored under four conditions (20 and 40 degrees C;33 and 75%RH) for tip to four weeks. Samples were analyzed by X-ray powder diffraction (XRPD) and differential scanning calorimetry. XRPD showed that all CBZ forms used in this Study formed cocrystals when co-milled with NIC (characteristic XRPD peaks at 6.6, 8.9, 10.1, 20.4, and 26.5 degrees 2 theta). Cocrystal formation was qualitatively found to be fastest for CBZ dihydrate (CBZ DH, similar to 1 min), followed by CBZ form 1 (similar to 6 min), and CBZ form III (similar to 15 min). Upon storage, cocrystals formed from CBZ DH were found to be physically stable under all conditions Studied. regardless of a small amount of impurity. For the two anhydrous forms (CBZ I and 111), the physical stability of the co-milled CBZ-NIC samples was dependent on the duration of milling, the relative humidity, and temperature of the storage conditions. Under "mild" storage conditions (i.e., 20 degrees C/33%RH), either partially or fully formed CBZ-NIC cocrystals were found to revert back to pure CBZ and NIC. Under "moderate" storage conditions (i.e., 20 degrees C/75%RH and 40 degrees C/33%RH), CBZ-NIC cocrystals reverting to pure CBZ and NIC would occur initially, followed by cocrystal formation with increasing storage time. On the other hand, "stress" storage conditions (i.e., 40 degrees C/75%RH) were found to be ideal for cocrystal formation and stability. Moisture has been found to favor cocrystallizat

关键词： Molecular Dynamics Simulation   trajectory   Mechanical systems   distributed computing system   kinetic simulation   PROCESSOR   Graphics Processing Unit  

摘要： We describe molecular dynamics simulations resulting in the folding the Fip35 Hpin1 WW domain. The simulations were run on a distributed set of graphics processors, which are capable of providing up to two orders of magnitude faster computation than conventional processors. Using the Folding@home distributed computing system, we generated thousands of independent trajectories in an implicit solvent model, totaling over 2.73 ms of simulations. A small number of these trajectories folded;the folding proceeded along several distinct routes and the system folded into two distinct three-stranded beta-sheet conformations, showing that the folding mechanism of this system is distinctly heterogeneous.

关键词： ultrafast protein folding   peripheral subunit-binding domain   barrier-limited folding   tryptophan fluorescence   temperature jump spectroscopy  

摘要： Barrier-free downhill folding has been proposed for the peripheral subunit-binding domain BBL. To date, ultrafast kinetic experiments on BBL, which are crucial for a mechanistic understanding of folding, have been hampered by the lack of good intrinsic spectroscopic probes. Here, we present a detailed kinetic characterization of three single-point tryptophan mutants of BBL that have suitable fluorescence properties for following microsecond and nanosecond folding kinetics using temperature jump fluorescence spectroscopy. Experiments were performed at pH 7, which is optimal for stability and minimizes complications that arise from the presence of ail alternative native-state conformation of BBL at lower pH. We examined the dependence of rate and equilibrium constants on concentration of denaturant and found that they follow well-established laws allowing kinetic transients to be related to events in folding and compared with equilibrium data. Logarithms of rate constants versus denaturant concentration yielded plots (chevrons) that are characteristic of barrier-limited folding for all mutants investigated, including a truncated sequence that was previously used in the proposal of downhill folding. The thermodynamic quantities calculated from the rate constants were in excellent agreement with those directly determined from equilibrium denaturation based on empirical two-state equations. We found that sequence truncation of BBL as used in studies proposing downhill folding leads to a large loss in helical content and protein stability, which were exacerbated at the low pH used in those studies. The kinetics and equilibria of folding of BBL fit to conventional barrier-limited kinetics. (C) 2009 Elsevier Ltd. All rights reserved.

关键词： Mechanical alloying   High temperature alloys   X-ray diffraction   Nanostructured materials  

摘要： Mechanical alloying (MA) is a versatile technique to produce different nanocrystalline and amorphous alloys. The ability of producing immiscible elements is one of the specific advantages of this method. High energy shaker ball milling has been used to produce W-20 wt.% Cu nanocomposite. Powders of elemental W (1-30 mu m) and Cu (1-15 mu m) were milled with a ball to powder ratio (BPR) of 16:1 for up to 30 h. The size and shape of the elemental and alloyed particles were examined by a scanning electron microscope (SEM). It has been observed that 30 h of milling produced homogeneous structure. X-ray diffraction (XRD) patterns confirmed partial alloying of Cu and W. As the sizes of W and Cu atoms are different, elastic strain energy due to misfit has been calculated to be about 5.3 kJ/mol. It has been concluded that among the factors contributing towards the enthalpy, stress exerted by dislocations on solute atoms is the major driving force for alloying. (c) 2008 Elsevier B.V. All rights reserved.

关键词： Hydrogen storage materials   Mechanochemical synthesis   Kinetics  

摘要： This work is aimed at quantifying mechanochemical effects in reactive solid-gas systems. It deals in particular with the kinetics of H-2 absorption processes on a Mg2Ni/Ni composite under thermal and mechanical activation. In a first series of experiments, powders were exposed to H-2 under static conditions for selected time intervals and successively subjected to mechanical treatment. In a second series, the latter was instead started in coincidence with the exposure of powders to H-2. The effects of mechanical processing on the H-2 absorption processes have been quantified via the accurate description of the absorption kinetics with suitable model curves. A tentative rationalization of experimental observations is proposed. (C) 2008 Elsevier B.V. All rights reserved.

关键词： 混合动力系统   工程机械   环境污染问题   能源短缺   研究开发   生产厂家   节能降耗   联合工作  

摘要： 随着能源短缺和环境污染问题日趋严重，鉴于混合动力系统在汽车上的成功应用，近年来国外各著名工程机械生产厂家普遍将研究开发方向转向了混合动力系统，混合动力系统已成为工程机械节能降耗、降低排放的的重要研究方向之一。 混合动力是指通过两种不同动力源的联合工作，使其充分发挥各自的优越性以提高能量的利用率。

关键词： 智能手机   500万像素   发电系统   不锈钢   电子混合动力手机   雅典  

摘要： 目前，瑞士奢侈手表制造商雅典（Ulysse Nardin）发布了一款新的智能手机Chairman，其内置了自动上弦发电系统。Ulysse Nardin共推出了金、金蓝、金钢、黑不锈钢和钢蓝五款Chairman手机，他们只是在材质上有差异，其他方面都一样。

关键词： 机械生化现象   原子力显微镜   DNase   I   纳米操纵   单分子研究   表面  

摘要： 本文采用了"多步的改进的动态分子梳"纳米操纵技术(multi-step modified dynamic molecular combing,MMDMC)实现样品制备获得不同拉伸程度单个DNA分子,利用原子力显微镜重定位成像和单分子分析,对反应前后不同拉伸程度DNA分子的DNase I酶切产生缺口情况进行统计,在一定拉伸范围内讨论了在表面上DNaseI酶切反应速率变化的动力学信息。该不同拉伸程度的DNA与DNase I相互作用的表面机械生化过程对于生物分子多次反复相互作用研究体系具有代表性意义。

关键词： 中国兵器工业集团   机械制造   企业发展   内蒙古   总会计师   公司   有限   集合体  

摘要： 王朝钦,历任湖北华中精密仪器厂财务处会计、副处长、处长,河南中原机械厂总会计师,湖北华光新材料有限公司董事、党委书记,湖北新华光信息材料股份有限公司董事、党委书记、副总经理兼财务总监,西安北方光电有限公司董事、总会计师。2008年1月至至今,任内蒙古第一机械制造(集团)有限公司董事、总会计师。2008年12月,荣膺中国总会计师协会授予的"中国总会计师贡献奖"。