Circulating markers of oxidative stress are raised in normal pregnancy and pre-eclampsia

OBJECTIVE: To determine whether circulating markers of oxidative stress are elevated in pre-eclampsia when appropriate precautions are taken to prevent in vitro oxidation DESIGN: A prospective study. SETTING: Nuffield Department of Obstetrics and Gynaecology, Oxford and The William Harvey Institute, London. SAMPLE: Three groups of women: those with pre-eclampsia (n = 19), control pregnant women (n = 19) matched for gestation, age and parity and a group of non pregnant individuals of reproductive age (n = 7). METHODS: Citrated plasma was stored at -80 degrees C with 20 micromol beta hydroxytoluene to prevent auto-oxidation. Plasma samples were assayed for levels of 8 epi-prostaglandin F2alpha, lipid hydroperoxides, malondialdehyde and also the lipid soluble antioxidant vitamin E. RESULTS: There were no differences in 8 epi-prostaglandin F2alpha, lipid peroxide or malondialdehyde levels between the groups of women with pre-eclampsia and those acting as pregnant controls. However, lipid hydroperoxides and malondialdehyde were significantly raised in both pre-eclampsia and normal pregnancy, compared with nonpregnant women. Vitamin E levels were similar in women with pre-eclampsia and those with a normal pregnancy, but in both groups levels were significantly higher than in nonpregnant women. CONCLUSION: Circulating markers of oxidative stress are raised in normal pregnancy and pre-eclampsia.     

Compositionally Graded Aluminum Oxide Coatings on Stainless Steel Using Laser Processing

A 1.5 mm thick fully dense alumina coating with a composition gradient from 100% Ni–20 wt% Cr at the substrate to 100% alumina on top has been developed on a 316 stainless steel sheet using Laser Engineered Net Shaping (LENS^™). The gradient coatings showed hardness in the range of 1800–2000 Hv, one of the highest reported so far due to high-density layers. During laser deposition, α-Al₂O₃ found to grow along the deposition direction with coarse columnar structure. The inherent advantage of this approach is to control simultaneously both location and composition leading to better interfacial properties of coatings.     

Dynamics of multibody systems in planar motion in a central gravitational field

Multibody systems in planar motion are modelled as two or more rigid components that are connected and can move relative to each other. The dynamics of such multibody systems in planar motion in a central gravitational force field is analysed. The equations of motion of the system include the equations for the orbital motion of the bodies, the orientation (attitude) of the assembly, and the relative orientation (shape) of the bodies with respect to each other. Dynamic coupling between these degrees of freedom gives rise to complex dynamical systems that are usually not integrable. Relative equilibria, corresponding to circular orbits of the multibody system, are obtained. The free dynamics has a symmetry due to a cyclic coordinate. Routh reduction is carried out to eliminate this coordinate and obtain the reduced dynamics. The stability of the relative equilibria is analysed using the Routh stability criterion when it is applicable; an expansion of the Hamiltonian in normal form is used otherwise. We apply the general results to a multibody system consisting of two hinged planar bodies, each modelled as a rigid massless link with a point mass at one end with their other ends connected by a hinge joint. We obtain the relative equilibria of this model, and carry out a stability analysis for the relative equilibria. Numerical simulations using a symplectic integrator are carried out for perturbations to these relative equilibria, to confirm their stability properties.     

Adjacency matrix generation from the image of graphs: a morphological approach

This paper presents a system for automatic generation of the adjacency matrix from the image of graphs. The graph, we assume, is printed or hand printed and available as a part of a document either separately or along with text and picture. A morphology-based approach is used here to separate components of the graphs: vertices, edges and labels. A novel technique is proposed to traverse the nonplanar edges joining the vertices. The proposed method may be used for logical compression of the information contained in the graph image in the form of an adjacency matrix. It may also be used to replace the cumbersome, error-prone and time-consuming manual method of generation of the adjacency matrix for graphs with large number of vertices and complex interconnections.     

Chip-level spray cooling of an LD-MOSFET RF power Amplifier

We report here the application of water spray cooling directly to the top surface of a lateral diffused metal oxide semiconductor field effect transistor (LD-MOSFET) in a 500-MHz RF power amplifier. With the amplifier running in Class A, spray cooling at a flow of 0.14 l/min increases the output power from 66 W to 84 W, and the power-added efficiency increases from 26% to 34%, all at 34 W input. This improvement is attributed to a large spray-induced reduction in junction temperature and total package thermal resistance. At the point of highest measured RF output and DC power dissipation, the reduction in junction temperature and total thermal resistance were estimated to be from /spl ap/214/spl deg/C to /spl ap/115/spl deg/C and from /spl ap/1.5/spl deg/C/W to /spl ap/0.6/spl deg/C/W, respectively, and the maximum spray-induced heat flux was /spl ap/162W/cm/sup 2/. In Class AB, the increase in output power and power-added efficiency are less, /spl ap/8%, but the amplifier can be driven harder before failure occurs. The maximum output in class AB is 79 W compared to 70 W without spray cooling.     

Time-dependent pH sensing phenomena using CdSe/ZnS quantum dots in EIS structure

Time-dependent pH sensing phenomena of the core-shell CdSe/ZnS quantum dot (QD) sensors in EIS (electrolyte insulator semiconductor) structure have been investigated for the first time. The quantum dots are immobilized by chaperonin GroEL protein, which are observed by both atomic force microscope and scanning electron microscope. The diameter of one QD is approximately 6.5 nm. The QDs are not oxidized over a long time and core-shell CdSe/ZnS are confirmed by X-ray photon spectroscopy. The sensors are studied for sensing of hydrogen ions concentration in different buffer solutions at broad pH range of 2 to 12. The QD sensors show improved sensitivity (38 to 55 mV/pH) as compared to bare SiO₂ sensor (36 to 23 mV/pH) with time period of 0 to 24 months, owing to the reduction of defects in the QDs. Therefore, the differential sensitivity of the QD sensors with respect to the bare SiO₂ sensors is improved from 2 to 32 mV/pH for the time period of 0 to 24 months. After 24 months, the sensitivity of the QD sensors is close to ideal Nernstian response with good linearity of 99.96%. Stability and repeatability of the QD sensors show low drift (10 mV for 10 cycles) as well as small hysteresis characteristics (<10 mV). This QD sensor is very useful for future human disease diagnostics.     

Effect of Multiwalled Carbon Nanotubes on the Properties of EPDM/NBR Dissimilar Elastomer Blends

In the presence of multiwalled carbon nanotubes (MWCNT), polar nitrile-butadiene rubber (NBR) and nonpolar ethylene propylene diene rubber (EPDM) blends were prepared following a melt mixing method. For the preparation of MWCNT filled EPDM/NBR blends, two mixing methods were used: direct mixing and the masterbatch dilution method. Various physical, mechanical, and morphological properties are explored to elucidate the dispersion behavior of MWCNTs. It was concluded that the preparation method influences the dispersion of the nanotubes in different rubber phases and the properties of these blends are controlled by the degree of dispersion of the nanotubes in the two phases.     

Hot Corrosion of Stabilized Zirconia Thermal Barrier Coatings and the Role of Mg Inhibitor

The 3–4 mol% yttria‐stabilized zirconia (YSZ) is widely used as a material for thermal barrier coating; however, the corrosive constituents present in fuel typically result in mechanical disintegration of YSZ coatings. The 3–4 mol% YSZ coatings with respective porosity of ~3% and ~22% have been undertaken with the objective to compare the hot corrosion behavior in air and sulfur‐rich atmospheres. The coatings are kept in contact with V₂O₅ + MgO powder mixture at 750°C for different dwell times of 24 and 76 h. The samples kept in air have shown intact YSZ layer for both the coatings, whereas a delamination of YSZ layer is observed for high porosity sample kept in sulfur‐rich atmosphere. XRD patterns of all the samples treated in sulfur‐rich atmosphere have indicated a phase transformation in YSZ from tetragonal to monoclinic. However, no such phase transformation has been found for samples treated in air. The V₂O₅‐induced hot corrosion attack on YSZ coating in air has been successfully inhibited by MgO, which forms a thermally stable Mg₃V₂O₈ compound. However, in sulfur‐rich atmosphere, MgO is partially consumed to form sulfates, which allows certain fraction of V₂O₅ to react with Y₂O₃ causing the degradation of top coat.     

Development and in-vivo evaluation of ondansetron gels for transdermal delivery

Nausea and vomiting are some of the major side effects caused by certain drug therapies, e.g. chemotherapy, radiotherapy and general anesthesia. Because of the nature of the symptoms, oral delivery is inappropriate, while intravenous administration may be unpractical. The aim of the present study was to develop a transdermal gel (2% Klucel®) for ondansetron, a first line 5-HT3-receptor-antagonist antiemetic. The effects of the penetration enhancer camphor and isopropyl-myristate (IPM) were first investigated in-vitro using modified Franz diffusion-cells and then tested in-vivo in a rabbit model by measuring skin and plasma concentrations. Since a disadvantage of transdermal delivery is a prolonged lag-time, the effect of skin treatment with a micro-needle roller was tested. The in-vitro permeation studies through excised porcine ear skin showed that the presence of 2.5% camphor or IPM increased steady state flux by 1.2- and 2.5-fold, respectively, compared to the control gel. Ondansetron was not detectable in either skin or plasma following in-vivo application of the base-gel, whereas the camphor gel and IPM gel delivered 20 and 81?µg/cm² of ondansetron, respectively. Microporation led to an increase in plasma C_max and AUC by 10.47?±?1.68-fold and 9.31?±?4.91-fold, respectively, for the camphor gel, and by 2.31?±?0.53-fold and 1.59?±?0.38-fold, respectively for the IPM gel. In conclusion, the 2.5% IPM gel demonstrated optimal in-vivo transdermal flux. Skin pretreatment with a micro-needle roller slightly improved the delivery of the IPM gel, whereas dramatically increased the transdermal delivery of the camphor gel.     

Creeping Flow of Viscoelastic Fluid Through a Packed Bed: Effect of Particle Shape and Porosity

Experiments were conducted to elucidate the effect of particle shape and porosity on frictional pressure drop for the flow of viscoelastic fluids through a packed bed under creeping flow regime. Extensive pressure drop-flow rate data were generated using different packing materials such as cylinders of different aspect ratios, square plates, triangles, and spheres covering a wide range of sphericity, 0.546 ≤ φ ≤ 1. Effect of bed porosity has been determined using uniform-size spheres of different diameters (4.38 mm, 5.76 mm, and 6.78 mm), covering column to particle diameter ratio in the range of 13.96–21.62; while porosity varies in the range of 0.345–0.375. The experimental results indicate that the modified Ergun correlation, proposed by Sobti and Wanchoo (2014 Sobti, A., and R. K. Wanchoo. 2014. Creeping flow of viscoelastic fluid through a packed bed. Industrial & Engineering Chemistry Research 53:14508–14518.[Crossref], [Web of Science ®] , [Google Scholar]), can adequately be applied for the nonspherical particles, provided the equivalent volume mean diameter (D_eq) together with sphericity (φ) is used instead of the diameter of the spherical particle (D_p), i.e., D_p = D_eqφ. Further, an attempt has been made to suitably define a packing structure parameter, [(1 ? ?)/(? φ)], which could well capture the balancing effect between porosity and sphericity.