Redox modulated hydrogelation of a self-assembling short peptide amphiphile

Hydrogels resulting from the self-assembly of small peptides are smart nanobiomaterials as their nanostructuring can be readily tuned by environmental stimuli such as pH,ionic strength and temperature,thereby favoring their practical applications.This work reports experimental observations of formation of peptide hydrogels in response to the redox environment.Ac-I 3 K-NH 2 is a short peptide amphiphile that readily self-assembles into long nanofibers and its gel formation occurs at concentrations of about 10 mmol/L.Introduction of a Cys residue into the hydrophilic region leads to a new molecule,Ac-I 3 CGK-NH 2,that enables the formation of disulfide bonds between self-assembled nanofibers,thus favoring cross-linking and promoting hydrogel formation.Under oxidative environment,Ac-I 3 CGK-NH 2 formed hydrogels at much lower concentrations(even at 0.5 mmol/L).Furthermore,the strength of the hydrogels could be easily tuned by switching between oxidative and reductive conditions and time.However,AFM,TEM,and CD measurements revealed little morphological and structural changes at molecular and nano dimensions,showing no apparent influence arising from the disulfide bond formation.     

非标准抛物方程只含有时间变量的热源识别反问题

探讨一类含对流项抛物方程的只含有时间变量热源识别反问题.这类问题是不适定的,即问题的解不连续依赖于测量数据.利用简化的Tikhonov正则化方法和拟逆正则化方法分别得到问题的正则近似解,并且分别给出正则解和精确解之间具有Ho¨lder型误差估计.     

基于出行需求的公交巴士服务构建初探

基于出行需求的交通服务(DRT,Demand Responsive Transport)就出行者的需求可以迅速地提供相应的出行服务,同时在应对个性化出行需求方面比常规公共交通方式更具时间和空间上的灵活性.作为近年来客运交通领域的一次革新,在欧美发达国家已经得到了较为广泛的应用.立足于DRT的基本理论,探索了DRT模式下...     

Sedimentation processes and sedimentary characteristics of tidal bores along the north bank of the Qiantang Estuary

A tidal bore is a unique Earth surface process, characterized by its highly destructive energy, predictable periodicities and magni-tudes, and the production of characteristic sedimentary features. Tidal bores and associated rapid flood flows are highly turbulent flows of the upper-flow regime with a velocity over several meters per second. Reynolds (Re) and Froude (Fr) numbers, respectively, are larger than 104 and 1.0, making them significantly different from regular tidal flows but analogous to turbidity currents. Until now, understanding of tidal-bore depositional processes and products has been limited because of the difficulty and hazards involved with gauging tidal bores directly. The Qiantang bore is known as the largest breaking bore in the world. Field surveys were carried out in May 2010, along the north bank of the Qiantang Estuary to observe the occurrence of peak bores, including regular observations of current, water level and turbidity at the main channel. Several short cores were sampled on the intertidal flats to study the characteristic sedimentary features of tidal bores. Hydrodynamic and sedimentological studies show that the processes of sediment resuspension, transport and deposition are controlled primarily by the tidal bores, and the subsequent abruptly accelerated and decelerated flood flows, which only account for one tenth of each semidiurnal tidal cycle in the estuary. Tidal-bore deposits are generally poorly sorted because of rapid sedimentation after highly mixed suspension by intense turbulence. This behavior is characteristic of the absence of tractive-current depositional components in a C-M diagram. It also goes along with well-developed massive bedding, graded bedding, basal erosion structures, convolute bedding and dewatering structures. Together, these sedimentary features can constitute fingerprinting of turbidites, widely distributed in the deep-water environment. However, a tidal bore is triggered by intensely deformed tidal waves propagating into a shallow-water environment, which returns to regular tidal flows rapidly after the passage of the bore head. The tidal-bore deposits are usually bounded by the intertidal-flat deposits with typical tidal beddings at the top and on both flanks. The difference between tidal-bore deposits (TBD) and tidal sandy/muddy deposits (TSD/TMD) is evident not only in sedimentary structures, but also in the grain-size composition. They can be clearly distinguished in grain-size bivariate plots, typically the plot of mean grain size vs. standard deviation (or sorting). Some trend variations generally exist in mean grain size with TBD>TSD>TMD, sorting with TMD>TBD>TSD (larger value indicating poorer sorting), and both skewness and kurtosis with TSD>TBD>TMD. These findings will undoubtedly shed new light on our understanding of tidal-bore sedimentology, ancient tidal-bore sedimentary facies and environments, and related oil-and-gas field prospecting.     

多重微孔生物反应床填料选取的探讨

多重微孔颗粒生物反应床是我公司研究开发的一种经济且能强有效去除垃圾渗滤液中污染物的反应器。本文先对矿化垃圾填料和多重微孔颗粒填料的挂膜性能和粒径分布进行比较,再以上海老港垃圾填埋场调节池出水为研究对象,构建多重微孔颗粒反应床的小试模型,对比20℃条件下反应柱和多重微孔颗粒反应柱对COD、NH3-N、TN指标的去除效果。     

图的扩张因子

图的扩张因子是度量图的连通性的一个重要参数.得到了图的扩张因子的上界和下界,刻画了达到上界与下界的图类,给出了n-维交叉超立方体和n-维增广立方体网络的扩张因子.     

改善民生增强常州经济增长消费驱动力的对策研究

消费是经济增长的恒动力,改善民生是促进消费需求的重要立足点.“十一五”以来,常州在扩消费促转型方面取得了很大成绩,但存在的问题也不容忽视.基于改善民生视角,针对限制常州居民消费增长的存在问题,提出相应的政策建议,以推进常州经济的又好又快发展.     

浅淡高速公路施工中的工程质量管理问题

高速公路的设计标准和工程质量要求高,必须重视和加强高速公路现场施工中的工程质量管理问题.文章从提高全员质量意识、重视工地试验室建设、重视现场跟踪检查、采取有效的质量奖罚措施、提高设计质量等方面较详细地阐述了高速公路现场施工中的质量管理问题.     

艺术形象在企业中的解析

国内的一些企业越来越多地开始看重产品和自身的形象，于是“CIS”——现代企业形象策略，作为一门实用性科学被中国各大企业引进，并在现代商战中占有举足轻重的地位。     

仿生裂缝自愈合混凝土

文章介绍了一种新型的工程建筑材料——仿生裂缝自愈合混凝土，这种材料的特性是，当混凝土材料出现裂缝时，部分液芯纤维或胶囊破裂，黏结液流出渗入裂缝，黏结液可以使混凝土重新愈合。