Solution for dissimilar elastic inclusions in a finite plate using boundary integral equation method

AbstractThis paper studies the boundary value problem for a finite plate containing two dissimilar inclusions. The matrix and the two inclusions have different elastic properties. The loadings applied along the outer boundary are in equilibrium. The mentioned problem is decomposed into three boundary value problems (BVPs). Two of them are interior BVP for the elastic inclusions, while the other is a BVP for the triply-connected region. Three problems are connected together through the common displacements and tractions along the interface boundaries. Explicit form for the complex variable boundary integral equation (CVBIE) is derived. After discretization of relevant BIEs, the solutions are evaluated numerically. Three numerical examples for different elastic constant combinations are provided

Premelting base pair opening probability and drug binding constant of a daunomycin-poly d(GCAT).poly d(ATGC) complex

We calculate room temperature thermal fluctuational base pair opening probability of a daunomycin-poly d(GCAT).poly d(ATGC) complex. This system is constructed at an atomic level of detail based on x-ray analysis of a crystal structure. The base pair opening probabilities are calculated from a modified self-consistent phonon approach of anharmonic lattice dynamics theory. We find that daunomycin binding substantially enhances the thermal stability of one of the base pairs adjacent the drug because of strong hydrogen bonding between the drug and the base. The possible effect of this enhanced stability on the drug inhibition of DNA transcription and replication is discussed. We also calculate the probability of drug dissociation from the helix based on the selfconsistent calculation of the probability of the disruption of drug-base H-bonds and the unstacking probability of the drug. The calculations can be used to determine the equilibrium drug binding constant which is found to be in good agreement with observations on similar daunomycin-DNA systems

Stress field around arbitrarily shaped cracks in two-dimensional elastic materials

The calculation of the stress field around an arbitrarily shaped crack in an infinite two-dimensional elastic medium is a mathematically daunting problem. With the exception of few exactly soluble crack shapes the available results are based on either perturbative approaches or on combinations of analytic and numerical techniques. We present here a general solution of this problem for any arbitrary crack. Along the way we develop a method to compute the conformal map from the exterior of a circle to the exterior of a line of arbitrary shape, offering it as a superior alternative to the classical Schwartz-Cristoffel transformation. Our calculation results in an accurate estimate of the full stress field and in particular of the stress intensity factors K_I and K_{II} and the T-stress which are essential in the theory of fracture.Comment: 7 pages, 4 figures, submitted for PR

Highly stable and active Ni-doped ordered mesoporous carbon catalyst on the steam reforming of ethanol application

AbstractA novel one-step direct synthesis of nickel embedded in an ordered mesoporous carbon catalyst (NiOMC) is done in a basic medium of nonaqueous solution by a solvent evaporation-induced self-assembly process. The NiOMC sample is characterized by a variety of analytical and spectroscopy techniques, e.g., N2 adsorption/desorption isotherm measurement, X-ray diffraction (XRD), transmission electron microscopy (TEM) and temperature-programed reduction (TPR). In this study, the NiOMC catalyst is found to exhibit superior catalytic activity for the steam reforming of ethanol (SRE), showing high hydrogen selectivity and durability. Ethanol can be completely converted at 350°C over the NiOMC catalyst. Also, the durability of the NiOMC catalyst on the SRE reaction exceeds 100h at 450°C, with SH2 approaching 65% and SCO of less than 1%

Efficacy of different protein descriptors in predicting protein functional families

10.1186/1471-2105-8-300BMC Bioinformatics8-BBMI

Magnetic resonance imaging of glutamate in neuroinflammation

AbstractInflammation in central nervous system (CNS) is one of the most severe diseases, and also plays an impellent role in some neurodegenerative diseases. Glutamate (Glu) has been considered relevant to the pathogenesis of neuroinflammation. In order to diagnose neuroinflammation incipiently and precisely, we review the pathobiological events in the early stages of neuroinflammation, the interactions between Glu and neuroinflammation, and two kinds of magnetic resonance techniques of imaging Glu (chemical exchange saturation transfer and magnetic resonance spectroscopy)

Breast tomosynthesis imaging configuration optimization based on computer simulation

Digital tomosynthesis is an innovative imaging technology for early breast cancer detection by providing three-dimensional anatomical information with fast image acquisition and low-dose radiation. Most of current breast tomosynthesis systems utilize a design where a single X-ray tube moves along an arc above objects over a certain angular range. The mechanical movement and patient motion during the scan may degrade image quality. With a carbon nanotube-based multibeam X-ray source, a new breast tomosynthesis modality is innovated, which will potentially produce better image quality with stationary beam sources and faster scan and it enables a variety of beam distributions. In this study, several beam distributions, such as beam sources spanning along a one-dimensional (1-D) parallel configuration and sources over a two-dimensional (2-D) rectangle shape are investigated based on computer simulations. Preliminary results show that 2-D rectangle shapes outperform 1-D parallel shapes by providing better Z-resolution, enhanced image contrast, reduced out-ofplane blur and artifacts and lower reconstruction noise. These benefits may expand tomosynthesis applications to diagnostic and interventional procedures