Matrix metalloproteinase expression in rat pancreatic islets

OBJECTIVE: To determine whether the type of prosthetic material and technique of placement influenced long-term complications after repair of incisional hernias. DESIGN: Retrospective cohort analytic study. SETTING: University-affiliated hospital. PATIENTS: Two hundred patients undergoing open repair of abdominal incisional hernias with prosthetic material between 1985 and 1994. INTERVENTIONS: Four types of prosthetic material were used and placed either as an onlay, underlay, sandwich, or finger interdigitation technique. The materials were monofilamented polypropylene mesh (Marlex, Davol Inc, Cranston, RI), double-filamented mesh (Prolene, Ethicon Inc, Somerville, NJ), expanded polytetrafluroethylene patch (Gore-Tex, WL Gore & Associates, Phoenix, Ariz) or multifilamented polyester mesh (Mersilene, Ethicon Inc). MAIN OUTCOME MEASURES: The incidence of recurrence and complications such as enterocutaneous fistula, bowel obstruction, and infection with each type of material and technique of repair were compared with univariate and multivariate analysis. RESULTS: On univariate analysis, multifilamented polyester mesh had a significantly higher mean number of complications per patient (4.7 vs 1.4-2.3; P<.002), a higher incidence of fistula formation (16% vs 0%-2%; P<.001), a greater number of infections (16% vs 0%-6%; P<.05), and more recurrent hernias (34% vs 10%-14%; P<.05) than the other materials used. The additional mean length of stay to treat complications was also significantly longer (30 vs 3-7 days; P<.001) when polyester mesh was used. The deleterious effect of polyester mesh on long-term complications was confirmed on multiple logistic regression (P=.002). The technique of placement had no influence on outcome. CONCLUSION: Polyester mesh should no longer be used for incisional hernia repair.     

Simulations of the dynamic behavior of a bipedal robot with trunk and arms subjected to 3D external disturbances in a vertical posture, during walking and during object handling

This paper provides a new approach to the bipedal robot stability problems in presence of external disturbances in vertical posture of the robot, during walking and during object handling. This approach is based on synergy between the dynamic motions of balancing masses and arms to reject large perturbations applied to the upper part of ROBIAN robot. In these cases, the stabilization is carried out in the first time with a trunk having 4 degrees of freedom (dof): one rotational and three translational movements. In the second time, the stabilization is performed with a system with arms and having 10 dof. During the walk, the trunk elements of ROBIAN reproduce necessary movements to perform the dynamic walking gait of the robot. The compensation of external three-dimensional efforts applied to the robot is achieved firstly by the trunk and secondly with the arms. This study allows us to determine on-line the required movements and accelerations of the trunk elements in order to maintain the robot stability and shows the importance of the arms for the robot stability.     

Alginate@Layered Silicate Composite Beads: Dye Elimination,Box–Behnken Design Optimization and Antibacterial Property

Journal of Inorganic and Organometallic Polymers and Materials - The discharge of industrial waste comprising organic pollutants into aquatic environment induces numerous health risks. Crosslinked...     

Bismuth alloying in GaAs: a first-principles study

We present a theoretical study mainly devoted to the investigation of the bowing parameter in the GaAs_1–xBi_x alloy. Results reveal that the fundamental band gap for GaAs is close to 0.08 eV and it corresponds to −2.01 eV for GaBi. The addition of Bi to GaAs serves to make the lattice constant of the crystal larger than GaAs and distorts the valence band. This causes an intrinsic asymmetry between the carrier mobility. The band gap of GaAsBi alloy decreases with increasing Bi content. Moreover, the non-linear variation of the lattice parameter is clearly visible with upward bowing parameter, equal to −0.378 ± 0.16 Å. Compared with preceding works on the matter, the band gap versus composition is well fitted with a downward bowing parameter of 1.74 ± 0.51 eV. This shows that the direct band gap of this alloy covers a spectral region ranging from near infrared to infrared.     

Predicted modifications in the direct and indirect gaps of Ge

The charge density of Ge was studied at various k-points and for various bands, by the ab initio pseudopotential method, using additionally the interstitial sites. The lowest X_c conduction-band points were found to be unique in having a high charge density in the interstitial site. It has been therefore predicted and verified that the X_c points move up in energy relative to the Γ_c point when closed-shell atoms (like H) are substituted at the interstitial sites. The calculations also indicate the change of the band-gap for HGeH.     

Stability and electronic properties of ZnxCd1−xO alloys

We investigated the structural and electronic properties of Zn_xCd_1−xO alloys, with Zn concentrations varying from 0% up to 100%. The calculations are based on the total energy calculations within the hybrid full potential augmented plane-wave plus local orbitals (APW+lo) method. We have used the local density approximation for the exchange and correlation potential. In particular we have studied the relative stability of several configurations of Zn_xCd_1−xO in rocksalt (B1) structure (the ground state configuration of CdO compound), or wurtzite (B4) structure (the ground state configuration of ZnO compound). The ground state properties, equilibrium lattice constants, bulk moduli, cohesive energies, and band structures for all Zn concentrations are presented. The densities of electron states are also determined for both the binary and their related ternary alloys. It is found that for Zn concentration lower than that of x = 0.625, the favored structure is a NaCl phase, while for Zn concentration x ≥ 0.625; the favored structure is a wurtzite phase. A model structure of 16-atom supercell is used.     

高放废物深地质处置库蒙脱土对铀酰的吸附阻滞行为:分子模拟研究

核废料处置库在长期运行过程中,地下水渗流会引起膨润土缓冲层水化学环境改变。运用分子动力学模拟方法,揭示含蒙脱土的膨润土缓冲材料对放射性核素铀酰的吸附机理及吸附复合物微观结构。模拟得到的复合物结构展现了铀酰与蒙脱土面的3种主要吸附模式:外球吸附、单键内球吸附、双键内球吸附。定量分析了在复杂水化学环境下3种铀酰种态与蒙脱土表面形成的复合物微观结构组成。通过计算复合物与蒙脱土表面的吸附能,发现高价阳离子和碳酸根离子的存在可以促进铀酰与缓冲材料表面形成稳定吸附。     

Pressure effects on the phonon modes in beryllium chalcogenides

We report first-principles calculations of the structural, lattice-dynamical and dielectric properties for zinc-blend beryllium chalcogenides: BeS, BeSe, and BeTe. The ground state properties, such as the lattice structure and bulk modulus, are calculated using a plane wave pseudopotential method within the density functional theory. A linear response approach is employed in order to derive the high-frequency dielectric constants, Born effective charges and phonon frequencies. Furthermore, the pressure dependence of phonon modes is also detailed.