ATP content and biomass activity in sequential anaerobic／aerobic reactors

Specific ATP content of volatile solids was measured to characterize the sludge activity in a sequential anaerobic/aerobic wastewater treatment system, with an upflow anaerobic sludge blanket (UASB) reactor and a three-phase aerobic fluidized bed (AFB) reactor. The wastewater COD level was 2000-3000 mg/L in simulation of real textile wastewater. The ATP content and the specific ATP contents of volatile solids at different heights of the UASB reactor and those of the suspended and immobilized biomass in the AFB reactor were measured. In the UASB reactor, the maximum value of specific ATP (0.85 mg ATP/g VS) was obtained at a hydraulic retention time (HRT) 7.14 h in the blanket solution. In the AFB reactor, the specific ATP content of suspended biomass was higher than that of immobilized biomass and increased with hydraulic retention time reaching a maximum value of 1.6 mg ATP/g VS at hydraulic retention time 4.35 h. The ATP content of anaerobes in the UASB effluent declined rapidly under aerobic conditions following a 2nd-order kinetic model.     

双酚A类同系物的雌激素效应及对MCF-7细胞的毒性

双酚A(bisphenol A, BPA)及其类似物作为聚碳酸酯的主要合成原料, 一直是环境污染的重要问题, 其环境分布及人体暴露是当今科学研究的热点. 为评估环境中BPA 类物质的毒性效应, 采用MTT 比色法检测了7 种BPA 类同系物对人雌激素受体(estrogen receptor,ER)缺失乳腺癌细胞MCF-7(ER–) 增殖活性的影响. 通过检测细胞乳酸脱氢酶(lactate dehydrogenase, LDH)露出率评估了目标物对MCF-7 细胞膜的损伤, 结果表明, 在0.01～1.00 μmol/L 浓度范围内, 受试化合物对MCF-7 细胞的毒性较小, LDH 少量露出; 而在10 和100 μmol/L 浓度下, 细胞增殖受到显著抑制, 细胞膜通透性显著改变, LDH大量露出. 同时采用ER 基因双杂交酵母实验检验了这几种BPA 类同系物的雌激素效应大小, 通过Logistic 模型对曲线进行了拟合, 并以模型估算的半数透导活性(EC50) 评估了7 种BPA 类同系物的雌激素效应活性, 其大小依次为TDP>BPAF>4Cl-BPA>BPC>BPA>BPE>BPAP. 这说明其雌激素效应机制可能是通过和ER 结合而产生的.     

佛手挥发油对B16细胞增殖及其酪氨酸酶活性的影响

为检测佛手挥发油对B16黑色素瘤细胞增殖及其酪氨酸酶活性的影响,采用台盼蓝排斥法测定了细胞存活率、瑞-姬氏混染法观察了细胞形态变化、吖啶橙/溴化乙锭染色法检测了细胞的凋亡与坏死,用酶学方法测定了细胞中酪氨酸酶活性.结果表明:佛手挥发油对B16黑色素瘤细胞增殖具有显著的抑制作用,呈剂量依赖性;62.50,125.00和250.00μg.mL-1佛手挥发油处理细胞6 h后,细胞核染色质凝聚于核膜内侧,呈固缩状或圆珠状,表现为典型的细胞凋亡特征;500.00μg.mL-1佛手挥发油处理细胞后,细胞膜破裂,出现细胞碎片,说明细胞已经坏死.酪氨酸酶活性检测结果显示:佛手挥发油对B16黑色素瘤细胞酪氨酸酶活性具有明显的抑制作用,且呈剂量依赖性.     

板模型中一类迁移算子的谱

本文研究的是板模型、散射和裂变是各向异性、具连续能量的非均匀介质的中子迁移算子的谱，证明了其严格占优本征值的存在性及该迁移系统解的渐近稳定性等一系列结果。     

水平井两层稳定岩屑传输规律研究

根据物质守恒定律和动量定理，建立了考虑岩屑床层中流体流动压降、悬浮层中岩屑颗粒受阻沉降的水平井偏心环空中两层稳定岩屑传输的数学模型，并用此模型进行了实例计算。研究结果表明，颗粒扩散系数方程中的实验回归系数应考虑成流速的函数，取值范围为0．014∽0．020；考虑岩屑床中流体流动压降后计算的环空压降与实际情况吻合较好。     

水平井两层稳定岩屑传输规律研究

根据物质守恒定律和动量定理,建立了考虑岩屑床层中流体流动压降、悬浮层中岩屑颗粒受阻沉降的水平井偏心环空中两层稳定岩屑传输的数学模型,并用此模型进行了实例计算。研究结果表明,颗粒扩散系数方程中的实验回归系数应考虑成流速的函数,取值范围为0.014～0.020;考虑岩屑床中流体流动压降后计算的环空压降与实际情况吻合较好。     

A novel receptor-operated Ca2+-permeable channel activated by ATP in smooth muscle

Receptor-operated Ca2+ entry has been proposed as a signalling mechanism in many cells. Receptor-operated Ca2+ channels (ROCs) were first postulated in smooth muscle by Bolton, van Breemen and Somlyo and Somlyo, but recordings of directly ligand-gated Ca2+ current are lacking. Here we describe receptor-operated Ca2+ current evoked in arterial smooth muscle cells by ATP, a sympathetic neurotransmitter. ATP activates channels with approximately 3:1 selectivity for Ca2+ over Na+ at near-physiological concentrations and with a unitary conductance of approximately 5 pS in 110 mM Ca2+ or Ba2+. The channels can be opened even at very negative potentials and resist inhibition by cadmium or nifedipine, unlike voltage-gated Ca2+ channels; they are not blocked by Mg2+, unlike NMDA (N-methyl-D-aspartate)-activated channels; they are directly activated by ligand, without involvement of readily diffusible second messengers, unlike cation channels in neutrophils and T lymphocytes. Thus, the ATP-activated channels provide a distinct mechanism for excitatory synaptic current and Ca2+ entry in smooth muscle.     

Possible role for fatty acyl-coenzyme A in intracellular protein transport

The transport of proteins between subcellular compartments is a vectorial, energy-requiring process mediated by the budding and fusion of a series of vesicular carriers. As yet, nothing is known of the chemical reactions that underlie these events, or how or in exactly what forms energy is used to sustain such movements. Here we report that fatty acyl-CoA acts as cofactor to a Golgi-associated protein factor (termed NSF) that is required for transport between cisternae of the Golgi stack in a cell-free system. This previously unsuspected connection may offer a link between the complex process of protein transport and a single, well-defined type of chemical reaction. We suggest that an ATP-dependent cycle of fatty acylation and deacylation may play an important role in driving rounds of vectorial protein transport.     

A cilium-independent role for intraflagellar transport 88 in regulating angiogenesis

Endothelial cilia are microtubule-based hair-like protrusions in the lumen of blood vessels that function as fluid mechanosensors to regulate vascular hemodynam...     

Macro-micro dynamic behaviors and fracture modes of roll bonded 7A52/ 7A01/7B52 aluminum laminates in high velocity deformation

Damage tolerance improvement in the lamination of aluminum alloy plates and composites has been reported in many studies. In the present study the macro-micro dynamic deformation behavior and related mechanisms of 7A52/7A01/7B52 laminated plates processed by hot roll bonding of 7A52, 7A01 and 7B52 plate at high strain rates and quasi-static compression has been investigated. The microstructure of the laminated plates was examined with backscatter diffraction (EBSD) techniques, scanning and transmission electron microscopies. The results showed that with increased strain rate, obvious strain rate hardening was observed in the single layer specimens. The peak flow stress of the multilayer samples was slightly higher than that of the 7A52 monolayer samples and much lower than that of the 7B52 monolayer samples at the same strain rate. Beyond the peak stress state, the strain hardening was replaced by thermal softening in the 7A52 layer, leading to low resistance of deformation and high tendency to facilitate deformation-induced adiabatic shear bands (ASBs) that consist of dynamic recrystallized grains. ASBs in laminated samples were deflected and bifurcated at the interface of 7A52 layer. In addition, bifurcated ASBs converged at the interface between the 7A52 and 7A01 layers. The high deformation resistance observed in the laminate under dynamic loading was a consequence of the high capacity for strain hardening in the 7A01 layer. This hardening effectively overcame the influences of thermal softening and dynamic recovery during dynamic loading. This study provides an understanding of the laminate's microstructure evolution during dynamic deformation and its relevance to the fracture modes of a multilayer structure under dynamic loading.     

WDM光网络中支持优先级的一种波长分配新算法

提出一种用于WDM光网络中支持优先级的波长分配算法———基于相对容量损失的动态门限法。该算法适于批处理,对于相同优先级的光路建立请求时采用计算相对容量的波长分配方法,而对不同优先级采用动态调整的方法,一方面在保证高优先级的请求有较低阻塞率时降低低优先级的阻塞率;另一方面更利于保护。文中给出计算机仿真结果。     

城市交通系统诱导控制的Stackelberg模型

在分析了城市交通系统诱导控制行为特点的基础上,指出诱导控制决策过程是一个多主体和多价值准则的决策过程.引入Stackelberg博弈理论,构建了城市交通系统诱导控制的Stackelberg模型,将问题描述为一个双层规划模型.最后,设计了基于灵敏度分析法的启发式求解算法.