基于样本块匹配的干涉图延拓方法

在快速傅里叶变换(FFT)方法处理单幅干涉图原理的基础上,提出一种基于样本块匹配的干涉图延拓方法,利用干涉图像的可信度和等照度线特征,来确定待填充块的优先权,然后在干涉图的已知区域寻找与待填充块最相似的样本块来进行填充。充分利用了干涉图的条纹特征,结合梯度变化方向有效地合成纹理信息,具有很好的延拓效果。最后将该干涉图延拓方法与傅里叶变换,合适的滤波函数和相位解包方法结合起来形成整套单幅干涉图处理方法。采用该单幅干涉图处理方法获得的波面峰谷值与Zygo移相干涉仪得到的平均相差不到λ/100,并且两种方法获得的波面均方根值平均相差不到λ/200。     

Untargeted Metabolomics Reveals the Potential Antidepressant Activity of a Novel Adenosine Receptor Antagonist

Depression is the most common mental illness, affecting approximately 4.4% of the global population. Despite many available treatments, some patients exhibit treatment-resistant depression. Thus, the need to develop new and alternative treatments cannot be overstated. Adenosine receptor antagonists have emerged as a promising new class of antidepressants. The current study investigates a novel dual A₁/A_2A adenosine receptor antagonist, namely 2-(3,4-dihydroxybenzylidene)-4-methoxy-2,3-dihydro-1H-inden-1-one (1a), for antidepressant capabilities by determining its metabolic profiles and comparing them to those of two reference compounds (imipramine and KW-6002). The metabolic profiles were obtained by treating male Sprague-Dawley rats with 1a and the reference compounds and subjecting them to the forced swim test. Serum and brain material was consequently collected from the animals following euthanasia, after which the metabolites were extracted and analyzed through untargeted metabolomics using both ¹H-NMR and GC-TOFMS. The current study provides insight into compound 1a’s metabolic profile. The metabolic profile of 1a was similar to those of the reference compounds. They potentially exhibit their antidepressive capabilities via downstream effects on amino acid and lipid metabolism.     

离散型织构表面液滴的铺展及其接触线的力学特性分析

针对离散型织构表面上液滴的铺展过程,采用数值模拟和润湿性实验相结合的方法,引入织构润湿因子θ*,得到了不同类型的离散型织构对固体表面润湿性的影响,在此基础之上分析了液滴铺展过程中接触线的力学特性,以期从微观界面力学的角度解释微织构对液滴铺展过程的促进作用.研究表明:离散型织构增大了液滴铺展过程中的固-液接触面积,位于铺展前沿的液体分子部分浸润织构内部,导致液面曲率和液滴内部的拉普拉斯压力增大,相邻离散型织构间的液体获得了额外的驱动力和能量,铺展速度加快,平衡接触角减小;槽状离散型织构对表面润湿性的影响程度最大,液滴在其上铺展过程具有各向异性特性.另外数值仿真分析表明,接触线的钉扎效应与固体表面粗糙度的大小和微织构类型密切相关,表面粗糙度越大,钉扎效应越明显,其中槽状织构对接触线的钉扎作用还具有方向性.      

Molecular Engineering of Surfaces by Plasma Copolymerization and Enhanced Cell Attachment and Spreading

The plasma copolymerization of acrylic acid and methyl vinyl ketone with 1,7-octadiene is reported. A range of surfaces including hydrocarbon plasma polymer, carbonyl-containing plasma copolymer and carboxyl-containing plasma copolymers have been prepared and characterized by means of X-ray photoelectron spectroscopy. The stability of these surfaces in water has been assessed at 37°C. The influence of their functional group chemistries on the attachment and spreading of osteoblast-like (ROS 17/2.8) and bone marrow stromal cells (BMSC) has been explored. The data reported show a strong correlation between the carboxyl group and the attachment and spreading of both ROS cells and BMSC. This relationship has been explored in some detail with the ROS cells. Actin-staining by direct immunofluorescence was used to visualize changes in cytoskeleton of ROS cells with substratum chemistry. As the concentration of the carboxyl groups increased cell number and cell spreading were notably enhanced. As few as 5 carboxyls per 100 carbons were sufficient to support good attachment and with cells showing well-defined polygonal cell morphology. Although cells attached to a hydrocarbon plasma polymer surface these cells had failed to spread. The attachment and spreading of BMSC were compared on a carboxyl-containing surface and on a hydrocarbon surface. There was a more marked difference in the number of cells that had attached to these two surfaces (cf. ROS cells). The spreading on the carboxyl surface was much more typical of BMSC. Results from an extended culture using primary cultures of bone marrow cells (BMC) are reported. These cells were not trypsinized and appear to be less sensitive to differences in surface chemistry (cf. BMSC). Even so, the results at 10 days indicate much greater biosynthetic activity on the carboxyl-containing surface.     

Wetting of phospholipid membranes on hydrophilic surfaces - Concepts towards self-healing membranes

We report on the wetting behavior of phospholipid membranes on solid surfaces immersed in aqueous solution. Using fluorescence microscopy, the spreading velocity of fluid bilayers advancing from a lipid source is investigated. The kinetic spreading coefficient was measured as a function of temperature for pure DMPC membranes and as a function of charge density and cholesterol content for binary membranes. A theoretical model for the membrane flow is presented, which takes into account the liquid crystalline bilayer architecture of the lipid membrane. The spreading power results from the membrane-solid VdW interaction and is dissipated in hydrodynamic shear flow as well as by inter-monolayer friction within the bilayer. The frictional drag causes a dynamic tension gradient in the spreading membrane, which is manifested by a single exponential decay of the fluorescence intensity profile along the spreading direction. Obstacles are shown to act as pinning centers deforming the advancing line interface. However, no depinning was observed, since the centers are circumflown without abrupt relaxation. Received 6 November 1998     

X-Ray Microanalysis in the Environmental SEM: A Challenge or a Contradiction?

 In this paper, the application of X-ray energy dispersive spectroscopy in the environmental scanning electron microscope is reviewed. Various techniques that have been used to remove the effects of the beam spreading in the gaseous environment are discussed, specifically the pressure variation techniques and the beam-stop method. The results of the application of modified versions, developed at the University of Michigan, are also presented. It is shown that quantitative analysis in the environmental SEM, operating at 30 kV, is possible at short working distances (6 mm to 7.2 mm, gas path length 1.2 mm to 2.2 mm) in the 70 to 350 Pa range.     

近自由面的多个水下爆炸气泡相互作用研究

将气泡运动阶段周围的流场假设为无黏、无旋、不可压缩的理想流体,运用边界积分法模拟流场中气泡的运动,并开发了三维计算程序,计算值与实验值吻合较好.用该方法模拟了近自由面多气泡之间的相互作用,包括同相气泡和异相气泡. 通过计算发现,气泡的周期随两气泡中心的距离减小而增大,这是由于多气泡之间存在抑制作用,特别是对异相气泡,这种抑制作用更加明显,称之为多气泡之间的抑制效应. 无论有、无自由面存在,多气泡之间均存在抑制效应,由于抑制效应导致同相与异相气泡相互耦合作用的动态特性存在巨大的差异,这些现象可为将来研究多个同时或延时产生的水下爆炸气泡的威力提供参考.      

A cellular automata model of epidemics of a heterogeneous susceptibility

In this paper we present a model with spatial heterogeneity based on cellular automata (CA). In the model we consider the relevant heterogeneity of host (susceptible) mixing and the natural birth rate. We divide the susceptible population into three groups according to the immunity of each individual based on the classical susceptible--infected--removed (SIR) epidemic models, and consider the spread of an infectious disease transmitted by direct contact among humans and vectors that have not an incubation period to become infectious. We test the local stability and instability of the disease-free equilibrium by the spectrum radii of Jacobian. The simulation shows that the structure of the nearest neighbour size of the cell (or the degree of the scale-free networks) plays a very important role in the spread properties of infectious disease. The positive equilibrium of the infections versus the neighbour size follows the third power law if an endemic equilibrium point exists. Finally, we analyse the feature of the infection waves for the homogeneity and heterogeneous cases respectively.     

Modelling of in vitro chondrocyte detachment

The experimental work of Huang et al. [Huang, W., Bahman, A., Torres, J.H., LeBaron R.G., Athanasiou, K.A., 2003. Temporal effects of cell adhesion on mechanical characteristics of the single chondrocyte. J. Orthop. Res. 21, 88-95] provides a novel experimental characterisation of the force required to detach single chondrocytes from a flat substrate with a horizontally moving probe. Measurements reveal that the force required to detach cells spread for six hours is eleven times greater than that required to detach cells spread for one hour. However, it is not clear if this phenomenon is entirely due to geometric changes of chondrocytes during spreading and the consequent increase in adhesion area between cell and substrate. The current computational study, using experimentally measured cell geometries and a cohesive zone model to simulate the cell-substrate interface, reveals that this is not the case. It is demonstrated that both an increase in cell stiffness and an increase in the cell-substrate interface strength during cell spreading are necessary to explain the experimental measurements. It is also revealed that the mechanism of cell detachment involves exclusively tangential debonding, with no lifting of the cell taking place at the cell-substrate interface. Finally, the effect of discrete focal adhesion regions on cell detachment is considered.     

混合自旋模型的动力学相变

考察了混合自旋模型的两种组态按Metropolis动力学随时间的演化,并分析了其在平方格子上的Darnage。计算结果表明存在有一高温相和一低温相,与平衡相变符合。