Preparation of Electrolytic Quasi-Solid-State Nanofibers for Dye-Sensitized Solar Cells

JOM - Nanofibers were prepared from a poly(acrylonitrile-co-vinyl acetate) [P(AN-co-VAC)]/polyvinylidene fluoride (PVDF) blend and used as a quasi-solid (QS) electrolyte for dye-sensitized solar...     

A Dual Inhibitor of DYRK1A and GSK3β for β-Cell Proliferation: Aminopyrazine Derivative GNF4877

Loss of β-cell mass and function can lead to insufficient insulin levels and ultimately to hyperglycemia and diabetes mellitus. The mainstream treatment approach involves regulation of insulin levels; however, approaches intended to increase β-cell mass are less developed. Promoting β-cell proliferation with low-molecular-weight inhibitors of dual-specificity tyrosine-regulated kinase 1A (DYRK1A) offers the potential to treat diabetes with oral therapies by restoring β-cell mass, insulin content and glycemic control. GNF4877, a potent dual inhibitor of DYRK1A and glycogen synthase kinase 3β (GSK3β) was previously reported to induce primary human β-cell proliferation in vitro and in vivo. Herein, we describe the lead optimization that lead to the identification of GNF4877 from an aminopyrazine hit identified in a phenotypic high-throughput screening campaign measuring β-cell proliferation.     

Evaluating the impact of several scrubbing systems on the tar removal efficiency from producer gas

Clean Technologies and Environmental Policy - Biomass gasification is the thermo-chemical conversion of biomass into producer gas. The latter can be then integrated in a combined heat and power...     

On the Effect of the Machine Saturation on SSR in Power Systems

A bifurcation analysis is performed to investigate the influence of iron saturation on the complex dynamics of a heavily loaded single-machine-infinitebusbar power system modeling the characteristics of the CHOLLA# 4 generator with respect to the SOWARO station. The system has five mechanical and two electrical modes. The results show that as the compensation level increases, the operating condition loses stability via a supercritical Hopf bifurcation. As a result, the power system oscillates subsynchronously with a small limit-cycle attractor. The instability is due to the interaction of the subsynchronous electrical mode with one of the torsional modes. When the machine saturation is considered, again the system loses stability via a supercritical Hopf bifurcation; however, it occurs at a slightly lower level of compensation, indicating that the influence of machine saturation is slightly destabilizing.     

Observations of Contact Measurements Using a Resonance-Based Touch Sensor

A study of the contact mechanisms between a resonator probe sensor and a broad range of engineering surfaces is presented. The resonator-based touch sensor used in these studies consists of a prismatic beam clamped at one end with a spherical probe attached at the other. Pairs of piezoelectric (PZT) elements cemented at either side of the beam along its axis are employed; one to actuate and the other to pick up the strain signals. Over a band of frequencies near to a resonance, the sensor behaves like second-order system. When oscillated near to its resonant frequency, interactions between the probe tip and specimen are detected by monitoring phase or frequency shifts using phase-locking techniques. As the probe approaches and contacts a surface, a range of phenomena are observed. Approximate theoretical models have been developed to predict the effects characteristic of added mass, stiffness, and damping (i.e., kinetic, potential and dissipative energy transfer) for contacts between clean solids and when contaminant films are present. These models predict that phase and frequency shifts can either increase or decrease depending upon the dominant phenomena in the contact region. For example, when a solid surface is contacted by a clean probe, the resonant frequency can either increase or decrease depending upon the ratio of elastic modulus to density, and this is demonstrated with contact measurements made on metals and rubbers. A systematic method for the identification of the dominant effect (if there is one) based on observations of frequency or phase shifts using either constant phase or constant frequency monitoring is presented.     

Asphyxial death caused by a laryngeal schwannoma: a case report

Neurogenic tumours of the larynx are unusual, with approximately 115 cases reported in the literature to date. Most of these lesions are benign, solitary submucosal nodules which present with hoarseness and are amenable to surgical resection. We present a case of a large pedunculated schwannoma arising in the aryepiglottic fold associated with sudden asphyxial death in an otherwise healthy young female.     

Upmodulation of alpha v beta 1 integrin expression on human tumor cells by human interleukin for DA cells/leukemia inhibitory factor and oncostatin M: correlation with increased cell adhesion on fibronectin

Integrins belong to a large family of heterodimeric membrane glycoproteins which mediate cell-cell or cell-extracellular matrix interactions. These interactions could play a major role during the migration of tumor cells across the extracellular matrix and vascular endothelium and would thus appear to be requisite for the metastatic process. Pretreatment of the Foss human melanoma cell line with HILDA/LIF or OSM, two cytokines involved in acute-phase response, increased the expression of membrane alpha v beta 1 1.5-2-fold. The same phenomenon was observed on the SK-N-SH human neuroblastoma cell line. alpha v beta 1 upmodulation was concomitant with improved tumor cells attachment to the fibronectin matrix. This greater adhesion of tumor cells to fibronectin was inhibited by specific monoclonal antibodies against alpha v or beta 1 integrin subunits. Similar results were obtained after TNF-alpha treatment. Our findings demonstrate the ability of HILDA/LIF and OSM to modulate tumor cell capacity to adhere to the matrix component, suggesting a potential role for these cytokines in modulation of tumoral progression.     

Microstructure and Properties of Spray Deposited 2024-20Si-5Fe Alloy

In this paper, a rapidly solidified Al-Si-Fe-Cu-Mg alloy was prepared by spray deposition. The microstructure of the alloy includes silicon phase and δ-(Al,Fe,Si). Al8Si6Mg3Fe, FeAl2 and small FeSi2 phases. The reasons of the formation of silicon and δ-(Al,Fe,Si) phase were analyzed. The tensile properties at the temperatures of room to 350℃ were investigated, and the strengthening mechanism was suggested. The wear resistance and cutability of the alloy were measured as well.     

Combining Kolb Learning Styles and Writing to Learn in Engineering Classes

This article combines Writing Across the Curriculum (WAC) assignments and the learning styles theory of David Kolb to enhance learning through writing in engineering education. Writing assignments are categorized by their appeal to each of four types of learners: divergers (Type 1), assimilators (Type 2), convergers (Type 3), and assimilators (Type 4). Specific WAC assignments are related to educational objectives in each of the four basic quadrants of the Kolb Learning Cycle, and examples are provided. Our purpose is to describe the Kolb Learning Cycle as a guide to using specific WAC writing assignments in engineering classes and to encourage a diversity of teaching styles.     

A systematic approach to identify the error motion of anN-degree of freedom manipulator

A generalised calibration technique for identifying the joint geometric parameters of an N-degrees-of-freedom (d.o.f.) robot manipulator model is presented. The technique is analogous to the synthesising calibration method applied in the calibration of coordinate measuring, machines. It describes the state of each joint by six d.o.f. and assumes rigid-body motion. The initial step in the calibration involves locating the axis of motion of each joint; the axes are then used to extract the kinematic parameters, introduced by Denavit-Hartenberg (D-H). In order to derive the generalised manipulator kinematic equation, the robot model is modified to include the six error motion components associated with each axis. The paper also addresses the problem of identifying the error motion components of each joint, on the basis of a set of measurement of three noncollinear points at the robot end-effector at various joint configurations. Because the technique is based on axis-by-axis calibration, other non-geometric errors such as joint backlash and gear transmission error may also be revealed.