Decreased nitric-oxide synthase activity causes impaired endothelium-dependent relaxation in the postischemic heart

Endothelial nitric-oxide synthase (eNOS) is an important regulator of endothelial function and vascular tone in biological tissues. While endothelial dysfunction occurs following ischemia and has been attributed to altered NO. formation, the biochemical basis for this dysfunction is unknown. Therefore, studies were performed to determine the effects of myocardial ischemia and reperfusion on eNOS in isolated rat hearts subjected to periods of global ischemia or ischemia followed by reperfusion. eNOS activity was assayed by L-[14C]arginine to L-[14C]citrulline conversion and alterations in the amount and distribution of eNOS determined by Western blotting and immunohistochemistry. While activity was preserved after 30 min of ischemia with a value of 1.1 +/- 0.1 pmol x min-1 x mg of protein-1, it decreased by 77% after 60 min and became nearly undetectable after 120 min. Reperfusion resulted in only a partial restoration of activity. The decline in activity with ischemia was due, in part, to a loss of eNOS protein. Hemodynamic studies showed that the onset of impaired vascular reactivity paralleled the loss of functional eNOS. Subjecting isolated eNOS to conditions of acidosis, which occur during ischemia, followed by restoration of pH as occurs on reperfusion, caused a combination of reversible and irreversible loss of activity similar to that seen in ischemic and reperfused hearts. Thus, loss of endothelial function following ischemia is paralleled by a loss of eNOS activity due to a combination of pH-dependent denaturation and proteolysis.     

Effect of chemical modification on FTIR spectra. I. Physical and chemical behavior of coir

Coir fibers were chemically modified through alkali treatment, and crosslinking with formaldehyde, para-phenylene diamine, phthalic anhydride, and combined crosslinking-cyanoethylation reactions in appropriate solvent and catalyst. The parent and chemically modified coir were characterized by FTIR spectra. The percent moisture regain, tensile strength, and behavior toward some chemical reagents (solubility %) of parent and chemically modified fibers have also been evaluated. The modified fibers showed significant hydrophobicity, improved tensile strength, and good chemical resistance. © 1995 John Wiley & Sons, Inc.     

Genetic analysis of adult-onset cataract in a city-based ophthalmic hospital

When oxygen delivery (DO2) critically decreases, oxygen consumption (VO2) becomes supply dependent. We examined whether end-tidal PCO2 (PetCO2) would identify supply dependency during shock. Five dogs (Group I) underwent progressive hemorrhage to decrease DO2 until they could no longer maintain a stable blood pressure. Five additional animals (Group II) were bled until VO2 decreased to 70% of baseline, followed by resuscitation. The PetCO2 versus time inflection point was compared with the DO2 at onset of supply dependency (DO2crit). DO2crit for Groups I and II were 6.9 +/- .4 and 8.1 +/- 1.3, respectively (p = NS), and not statistically different from the DO2 values at which PetCO2 decreased (6.6 +/- .7 and 6.3 +/- .7 mL/kg per min, respectively). AT constant minute volume, PetCO2 effectively indicated the onset of supply dependency and rapidly increased during resuscitation, paralleling the changes in VO2 in this model of hemorrhagic shock.     

Synthesis of cyclic carbonates from carbon dioxide and epoxides using alkali metal halide supported liquid phase catalyst

Using combination of Mn–Co transition metal species with N-hydroxyphthalimide as a catalyst for one-step oxidation of cyclohexane with molecular oxygen in acetic acid at 353 K can give more than 95% selectivity towards oxygenated products with adipic acid as a major product at a high conversion (ca. 78%). A turnover number of 74 for this partial oxidation are also recorded.     

Speed ripple minimization in PM synchronous motor using iterative learning control

Permanent-magnet synchronous motor (PMSM) drives are widely used for high-performance industrial servo applications where torque smoothness is an essential requirement. However, one disadvantage of PMSM is parasitic torque pulsations, which induce speed oscillation that deteriorates the drive performance particularly at low-speeds. To suppress these speed ripples, two iterative learning control (ILC) schemes implemented in the time domain and frequency domain respectively are proposed in this paper. Although a conventional proportional-integral (PI) speed controller does suppress speed ripples to a certain extent, it is not adequate for many high performance applications. Thus, the proposed plug-in ILC controller is applied in conjunction with a PI speed controller to further reduce the periodic speed ripples. Experimental verification of the two schemes is carried out, and test results obtained demonstrate that the scheme implemented in frequency domain has better performance in reducing speed ripples than that implemented in time domain because of the elimination of forgetting factor that is indispensable for robustness in time domain learning method.     

Integrated energy system for industrial complexes. Part I: A linear programming approach

A personal-computer based model of an Integrated Energy System for Industrial Estates (IESIE) has been developed as a pre-feasibility tool: it addresses the total energy concept by combining a set of CHP plant(s), boilers, vapor-compression and absorption chillers, national grid and utility transportation system. The core of the general model is the linear programming (LP) model which takes into account the changing demand-pattern of various loads and their tariffs, standby charge of electricity, unit fuel price, equipment costs, land cost, depreciation, O & M expenses, interest rate, taxes, etc. The output of the LP model yields the minimum total operating cost, optimal sizes of the equipment and their respective operational schedules. The hot utility and cold utility transportation model estimates the economic-minimum pipe size, considering installation cost, heat loss/gain cost and pumping cost. The heat balance model finds the thermal cycle equipment sizes as well as the variation of the heat-to-power ratio with load. Finally the economic model does the cash-flow analysis to determing whether the project will yield a required rate-of-return to be economically viable.

Simulations have been done using the model considering a number of sample load patterns with the prevailing cost factors in India. An after tax IRR of 20% was found for sites having load factors greater than 0·6, and up to 10 km utility transportation distance.     

Characteristics of DC magnetron sputtered ternary cobalt-nickel silicide thin films for ultra shallow junction devices

Ternary cobalt-nickel silicide thin films were synthesized by DC magnetron sputtering from an equiatomic cobalt-nickel alloy target. Grazing incidence XRD, Rutherford back scattering, high-resolution cross-sectional TEM analysis and electrical study were carried out to investigate the formation of silicide, stoichiometry, film thickness, depth profile and sheet resistance of as-deposited and post-deposition annealed films. The ternary silicide layer thickness was calculated from RBS simulated data, which was found to vary 20-43 nm for as-deposited and different vacuum annealed films. A minimum value of sheet resistance 2.73 Ω/sq corresponding to a resistivity of ∼8.4 μΩ-cm was obtained for optimized deposition and annealing conditions.