Erythropoietin Action in Stress Response,Tissue Maintenance and Metabolism

Erythropoietin (EPO) regulation of red blood cell production and its induction at reduced oxygen tension provides for the important erythropoietic response to ischemic stress. The cloning and production of recombinant human EPO has led to its clinical use in patients with anemia for two and half decades and has facilitated studies of EPO action. Reports of animal and cell models of ischemic stress in vitro and injury suggest potential EPO benefit beyond red blood cell production including vascular endothelial response to increase nitric oxide production, which facilitates oxygen delivery to brain, heart and other non-hematopoietic tissues. This review discusses these and other reports of EPO action beyond red blood cell production, including EPO response affecting metabolism and obesity in animal models. Observations of EPO activity in cell and animal model systems, including mice with tissue specific deletion of EPO receptor (EpoR), suggest the potential for EPO response in metabolism and disease.     

Merox and Related Metal Phthalocyanine Catalyzed Oxidation Processes

Alkyl and aromatic mercaptans are among important organic sulfur compounds distributed in petroleum products. The mercaptans cause foul odor and are corrosive toward metals. In addition, mercaptans may cause oxidative deterioration as well as inhibit the performance of various additives (TEL, antioxidants) in finished products. Therefore, it is necessary to remove them, either by extractive processes or by converting them into innocuous disulfides. Such processes are usually referred to as “sweetening.”     

Hybrid composite friction materials reinforced with combination of potassium titanate whiskers and aramid fibre: Assessment of fade and recovery performance

Composite friction materials based on synergistic ternary combination of potassium titanate whiskers, aramid fibre and graphite have been characterized for friction braking performance on Krauss friction tester. The dynamics of friction build-up and friction-decay as a function of number of braking instances and modes of braking cycles have been found to be more consistent in the composites with ≥7.5 wt% of aramid fibres whereas the absolute friction effectiveness remained higher in the composites with ≥25 wt% of potassium titanate whiskers. Wear surface morphology has revealed topographical variations and their underlying role in controlling the friction and wear performance.     

Thermo-mechanical correlations to erosion performance of short carbon fibre reinforced vinyl ester resin composites

Thermo-mechanical properties and erosion performance of short carbon fibre reinforced vinyl ester resin based isotropic polymer composites with four different fibre weight fractions have been investigated. The storage, loss and damping characteristics were analysed to assess the energy absorption/viscous recoverable energy dissipation and reinforcement efficiency of the composites as a function of fibre content in the temperature range of 0–140 °C. The composite with 30 wt.% of short carbon fibres has been observed to exhibit superior thermo-mechanical response with highest energy dissipation/damping ability accompanied with a constant storage modulus without any substantial decay till 60 °C. The erosion rates (Er) of these composites are evaluated at different impingement angles (30–90°), fibre loadings (20–50 wt.%), impact velocities (43–76 m/s), stand-off distances (55–85 mm) and erodent sizes (250–600 μm) following the erosion test schedule in an air jet type test rig. An optimal parameter combination is determined and subsequently validated for erosion rate minimization following Taguchi method and by conducting confirmation experiments. A correlation between the loss-modulus inverse and the erosion rate has been observed which conceptually establishes a possible mechanistic equivalence between erosion and dynamic mechanical loading modes. The morphologies of eroded surface are examined by the scanning electron microscopy to investigate the nature of wear-craters, material damage mode and other qualitative attributes responsible for promoting erosion.     

Merox and Related Metal Phthalocyanine Catalyzed Oxidation Processes

Alkyl and aromatic mercaptans are among important organic sulfur compounds distributed in petroleum products. The mercaptans cause foul odor and are corrosive toward metals. In addition, mercaptans may cause oxidative deterioration as well as inhibit the performance of various additives (TEL, antioxidants) in finished products. Therefore, it is necessary to remove them, either by extractive processes or by converting them into innocuous disulfides. Such processes are usually referred to as “sweetening.”     

New galvanic cell designs for minimizing electrode polarization

New galvanic cell designs, incorporating one or two buffer electrodes, are developed to minimize the electrode polarization caused by electrochemical permeability of the electrolyte at high temperature. When a nonpolarizable reference electrode is employed, a cell with three-electrode compartments can be used to measure the chemical potential of oxygen in two-phase fields of ternary systems, associated with one degree of freedom at constant temperature. A buffer electrode is placed between the reference and measuring electrodes. The buffer electrode, maintained at approximately the same oxygen chemical potential as the measuring electrode, absorbs the semipermeability flux of oxygen between reference and measuring electrodes. When the reference electrode is polarizable, two buffer electrodes are required between the reference and measuring electrodes. The reference and reference-buffer electrodes have the same chemical potential of the active species. Similarly the measuring electrode and its buffer are of approximately the same chemical potential. A significant chemical potential difference exists only between the two buffers, which may become polarized due to coupled transport of ions and electronic defects through the electrolyte. Since the reference and measuring electrodes are insulated, the emf of the solid state cell is unaffected. The use of the buffer electrode designs permit more accurate thermodynamic measurements on metal and ceramic systems at high temperature.     

Gradient solid electrolytes for thermodynamic measurements: System Na2CO3-Na2SO4

The thermodynamic properties of Na₂CO₃-Na₂SO₄ solid solution with hexagonal structure have been measured in the temperature range of 873 to 1073 K, using a composite-gradient solid electrolyte. The cell used can be represented as Pt, CO₂′ + O₂∥ Na₂CO₃Na₂ (CO₃)_x(SO₄)_1-x) ∥ CO₂″ + O₂″, Pt The composite-gradient solid electrolyte consisted of pure Na²CO³ at one extremity and the solid solution under study at the other, with variation in composition across the electrolyte. A CO₂ + O₂ + Ar gas mixture was used to fix the chemical potential of sodium at each electrode. The Nernstian response of the cell to changes in partial pressures of CO₂ and O₂ at the electrodes has been demonstrated. The activity of Na₂CO₃ in the solid solution was measured by two techniques. In the first method, the electromotive force (emf) of the cell was measured with the same CO₂ + O₂ + Ar mixture at both electrodes. The resultant emf is directly related to the activity of Na₂CO₃ at the solid solution electrode. By the second approach, the activity was calculated from the difference in compositions of CO₂ + O₂ + Ar mixtures at the two electrodes required to produce a null emf. Both methods gave identical results. The second method is more suitable for gradient solid electrolytes that exhibit significant electronic conduction. The activity of Na₂CO₃ exhibits positive deviation from Raoult’s law. The excess Gibbs’ energy of mixing of the solid solution can be represented using a subregular solution model such as the following: ΔG^E = X(1 - X)[6500(±200)X + 3320(±80)(l - X)] J mol^-1 whereX is the mole fraction of Na₂CO₃. By combining this information with the phase diagram, mixing properties of the liquid phase are obtained.     

Effect of fiber loading and orientation on mechanical and erosion wear behaviors of glass–epoxy composites

For a composite material, its mechanical behavior and surface damage by solid particle erosion depend on many factors. One of the most important factors is the fiber content. Similarly, these properties are also greatly affected by the fiber orientation. In this work, a series of experiments were carried out to investigate the influence of fiber loading and fiber orientation on mechanical and erosion behavior of glass fiber‐reinforced epoxy composites. The composites were fabricated with three different fiber loadings (20, 30, and 40 wt%) and at four different fiber orientations (15°, 30°, 45°, and 60°). The conclusions drawn on the basis of the experimental findings are discussed, and composite with 30° fiber orientation shows better microhardness compared with other fiber orientations irrespective of fiber loading. Similar observations are also noticed for other mechanical properties of the composites, such as tensile strength, flexural strength, interlaminar shear strength, impact strength, etc. Finally, the morphology of eroded surfaces is examined using scanning electron microscopy (SEM), and possible erosion mechanisms are identified. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers     

Incompleteness of bifurcation diagram in predicting the behaviour of Ćuk converter in discontinuous conduction mode

The bifurcation phenomena have been studied in current mode‐controlled ?uk converter considering continuous conduction as well as discontinuous conduction mode of operation. Some peculiarities have been observed in discontinuous conduction mode, which indicate some incompleteness of the bifurcation diagrams in providing details of the system behaviour. Copyright © 2007 John Wiley & Sons, Ltd.     

The 9‐point hedonic scale and hedonic ranking in food science: some reappraisals and alternatives

The 9‐point hedonic scale has been used routinely in food science, the same way for 60 years. Now, with advances in technology, data from the scale are being used for more and more complex programs for statistical analysis and modeling. Accordingly, it is worth reconsidering the presentation protocols and the analyses associated with the scale, as well as some alternatives. How the brain generates numbers and the types of numbers it generates has relevance for the choice of measurement protocols. There are alternatives to the generally used serial monadic protocol, which can be more suitable. Traditionally, the ‘words’ on the 9‐point hedonic scale are reassigned as ‘numbers’, while other ‘9‐point hedonic scales’ are purely numerical; the two are not interchangeable. Parametric statistical analysis of scaling data is examined critically and alternatives discussed. The potential of a promising alternative to scaling itself, simple ranking with a hedonic R‐Index signal detection analysis, is explored in comparison with the 9‐point hedonic scale. © 2014 Society of Chemical Industry