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The aim of the current investigation is fabricate the FeCrBSiMn alloy coating onto 310S stainless steel substrate by wire arc spraying process and to study degradation behavior of the coating exposed to molten salt environment (Na2SO4-82%Fe2(SO4)3) at 900 °C under cyclic conditions after 50 cycles. X-ray diffraction (XRD) and scanning electron microscopy/energy-dispersive analysis (SEM/EDS) were used to characterize morphology of coated and uncoated samples for substantiating the degradation mechanisms. The dense and globular morphology of the coatings is observed from the SEM analysis. The maximum microhardness of coating was found to be (430-1060 HV). The coating showed superior hot corrosion resistance as compared to boiler steel due to the formation of protective scale, Cr2O3. The protective scale formed at high temperature prevents hot corrosion of coated boiler steel as evident from the morphological studies made by using FE-SEM/EDS. The FeCrBSiMn alloy coating showed good adherence to the 310S substrate with negligible microspalling of the scales. [ABSTRACT FROM AUTHOR]

NiCrAlY coatings are widely used in gas turbines for the protection against the high temperature oxidation and corrosion. Micro and Nanocrystalline NiCrAlY coatings on Superalloy were fabricated by Sputtering and High Velocity Oxide Fuel Spray (HVOF), respectively, in the present work. The coatings were subjected to high temperature cyclic oxidation at 900 °C in presence of air to investigate its oxidation kinetics. The weight change of the microcrystalline (mc) and nanocrystalline (nc) coatings was monitored after each cycle to establish its degradation rate in the corrosive environment. The parabolic rate constant was evaluated using the weight change data obtained for both mc and nc coatings by least square fitting method. It was observed that the nanocrystalline coatings showed lower value of parabolic rate constant as compared to that of its bulk coatings. The protective oxide scales were identified by the characterisation techniques such as XRD, FESEM, EDS and X-ray Mapping. The nanocrystalline NiCrAlY coatings exhibit superior high temperature corrosion resistance in air due to the formation of adherent, non-porous, and uniform protective scales such as NiCr2O4, Cr2O3 etc when compared to mc coatings. On the other hand, the protective scales formed over the mc coatings are non-uniform, discontinuous which provides relatively less protection in the corrosive environment. The mechanisms of nanosize effect on the rapid formation of protective scale, through high diffusivity of alloying elements, in nc coatings are proposed. [ABSTRACT FROM AUTHOR]

Advances in the understanding of the endogenous cannabinoid system have led to several therapeutic indications for new classes of compounds that enhance cannabinergic responses. Endocannabinoid levels are elevated during pathogenic conditions, and inhibitors of endocannabinoid inactivation promote such on-demand responses. The endocannabinoids anandamide and 2-arachidonoyl glycerol have been implicated in protective signaling against excitotoxic episodes, including seizures. To better understand modulatory pathways that can exploit such responses, we used the new generation compound AM6701 that blocks both the anandamide-deactivating enzyme fatty acid amide hydrolase (FAAH) and the 2-arachidonoyl glycerol-deactivating enzyme monoacylglycerol lipase (MAGL) with equal potency. Also studied was the structural isomer AM6702 which is 44-fold more potent for inhibiting FAAH versus MAGL. When applied before and during kainic acid (KA) exposure to cultured hippocampal slices, AM6701 protected against the resulting excitotoxic events of calpain-mediated cytoskeletal damage, loss of presynaptic and postsynaptic proteins, and pyknotic changes in neurons. The equipotent inhibitor was more effective than its close relative AM6702 at protecting against the neurodegenerative cascade assessed in the slice model. In vivo, AM6701 was also the more effective compound for reducing the severity of KA-induced seizures and protecting against behavioral deficits linked to seizure damage. Corresponding with the behavioral improvements, cytoskeletal and synaptic protection was elicited by AM6701, as found in the KA-treated hippocampal slice model. It is proposed that the influence of AM6701 on FAAH and MAGL exerts a synergistic action on the endocannabinoid system, thereby promoting the protective nature of cannabinergic signaling to offset excitotoxic brain injury. [ABSTRACT FROM AUTHOR]

Abstract: High energy synchrotron X-ray diffraction measurements have been performed to provide quantitative microscopic guidance for modeling of fatigue crack growth. Specifically we report local strain mapping, along with in situ loading strain response, results on 4140 steel fatigue specimens exhibiting the crack growth retardation “overload effect”. Detailed, 2D, εyy -strain field mapping shows that a single overload (OL) cycle creates a compressive strain field extending millimeters above and below the crack plane. The OL strain field structures are shown to persist after the crack tip has grown well beyond the OL position. The specimen exhibiting the maximal crack growth rate retardation following overload exhibits a tensile residual strain region at the crack tip. Strain field results, on in situ tensile loaded specimens, show a striking critical threshold load, F c, phenomenon in their strain response. At loads below F c the strain response is dominated by a rapid suppression of the compressive OL feature with modest response at the crack tip. At loads above F c the strain response at the OL position terminates and the response at the crack tip becomes large. This threshold load response behavior is shown to exhibit lower F c values, and dramatically enhanced rates of strain change with load as the crack tip propagates farther beyond the OL position. The OL strain feature behind the crack tip also is shown to be suppressed by removing the opposing crack faces via an electron discharge cut passing through the crack tip. Finally unique 2D strain field mapping (imaging) results, through the depth of the specimen, of the fatigue crack front and the OL feature in the wake are also presented. [Copyright &y& Elsevier]

Abstract: Nanocomposites of yttria-stabilized zirconia (YSZ), containing 20 and 40wt% alumina, were prepared by a two-step process: (1) fine-particle aggregates of the constituent phases were melted and homogenized in a high enthalpy plasma, prior to rapid quenching in water to obtain metastable starting powders, and (2) the metastable powders were consolidated by hot isostatic pressing (HIP), under conditions designed to ensure the formation of nanocomposites by controlling the metastable-to-stable phase transformation during sintering. In both cases, the resulting nanocomposites had completely uniform structures, comprising 27 and 50vol% of α-Al2O3 in a tetragonal YSZ matrix phase. Measurements of hardness and indentation toughness were correlated with observed structures. [Copyright &y& Elsevier]

The present investigation deals with the excellent catalytic effect of graphene templated Ti–Ni–Fe nanoparticles (Ti–Ni–Fe@Gr) on de/re-hydrogenation characteristics of MgH 2. The catalytic effect of Ti–Ni–Fe@Gr on MgH2 has also been compared with Ti@Gr, Ni@Gr, and Fe@Gr. It has been found that Ti–Ni–Fe@Gr lowers the onset desorption temperature up to 252 °C with improved kinetics and cyclability for the hydrogen release and absorption from MgH 2. The presence of a multivalence environment around Mg/MgH 2 has been analyzed by XPS analysis which gives the evidence of possible electronic exchange between the catalyst and Mg/MgH 2 during de-/rehydrogenation. Since Mg/MgH 2 and Ti–Ni–Fe are both anchored on graphene template, agglomeration detrimental to cycling is not possible. Thus negligible degradation of 0.22 wt% has been observed even after 24 cycles of de/re-hydrogenation. • The catalytic effect of Graphene templated transition metals (Ti, Ni, Fe) on de-/rehydrogenation of MgH 2 /Mg has been studied. • MgH 2 :Ti–Ni–Fe@Gr composite shows the lowest desorption temperature in the present study. • MgH 2 :Ti–Ni–Fe@Gr shows good cyclic stability. [ABSTRACT FROM AUTHOR]

Optical limiting behavior of three ferrocenyl substituted calixarenes (FSCs) where ferrocenyl group is attached via ethynyl( a ), meta-( b ) and para-( c ) ethynyl phenyl spacers studied with nanosecond pulses at 532 nm is in the order c > a > b . While, with femtosecond laser pulses at 800 nm strength of nonlinearity is in the order c > b > a . Largest nonlinear refraction ( n 2 = 9.5 × 10 −16 cm 2 /W) is estimated for the FSC c . Nonlinear absorption in these FSCs is attributed to three-photon absorption. Optical limiting behavior with nanosecond laser pulses is mainly due to thermal nonlinearity and reverse saturable absorption, whereas, with femtosecond laser pulses mainly intrinsic electronic nonlinearity contributes. [ABSTRACT FROM AUTHOR]

Abstract: Near stoichiometric LiNbO3 crystal wafers of thickness up to 2mm were prepared by vapour transport equilibration technique (VTE) at various process temperatures. Crystals were characterised by measurement of the UV absorption edge, refractive index, second harmonic generation (SHG) efficiency, and conoscopy pattern analysis. The comparison of VTE treated crystals show that the blue shift in cut off wavelength occurred with the increasing process temperature (i.e. increasing Li/Nb ratio). The refractive indices were found decreasing with increasing process temperature of VTE samples. The SHG efficiency increases in the range of 1.98–2.3 times for the VTE processed samples with respected to congruent crystals. Conoscopy pattern reveals the optical homogeneity of the VTE treated crystal. [Copyright &y& Elsevier]

BACKGROUND: Various drugs have been approved for the treatment of Alzheimer's disease (AD) in the United States and Canada, including donepezil and rivastigmine, although questions remain as to their efficacy, effectiveness, and long-term benefits. OBJECTIVE: The goal of this study was to conduct a best-evidence synthesis of data on the efficacy and cost-effectiveness of donepezil and rivastigmine in the treatment of AD. METHODS: Relevant published randomized controlled trials (RCTs) and Phase IV open-label extension studies (excluding abstracts) were identified through searches of MEDLINE, HealthSTAR, and PsycINFO for the period January 1984 to October 2001. The bibliographies of retrieved articles were searched for additional publications. For inclusion in the best-evidence synthesis, clinical trials had to pass a blinded quality assessment (score > or =5 on the Jadad scale) and use National Institute of Neurological and Communicative Disease and Stroke-Alzheimer's Disease and Related Disorders Association diagnostic criteria. Economic studies were selected using National Health Service Centre for Reviews and Dissemination criteria for reporting critical summaries of economic evaluations. RESULTS: Nine RCTs of donepezil and 2 of rivastigmine were identified and met inclusion criteria for the best-evidence synthesis. Eight donepezil trials and both rivastigmine trials included patients with mild AD (Mini-Mental State Examination [MMSE] score, 15-27) or moderate AD (MMSE score, 8-14); 1 donepezil trial included patients with moderate or severe AD (MMSE score, 0-7). In the RCTs of donepezil, the mean decrease in scores on the Alzheimer's Disease Assessment Scale-cognitive subscale (ADAS-cog) was greater with active treatment than with placebo (lower scores indicate less cognitive deterioration). In the RCTs of rivastigmine, ADAS-cog scores decreased over the follow-up period with both active treatment and placebo; however, scores decreased more with active treatment. Three Phase IV studies of donepezil and I Phase IV study of rivastigmine were identified. Their results were consistent with those of the RCTs. Ten economic studies (7 donepezil, 3 rivastigmine) were identified and reviewed. In 4 of the donepezil studies and all 3 rivastigmine studies, use of the drug cost less than a no-drug strategy. CONCLUSIONS: The efficacy data indicate that both donepezil and rivastigmine can delay cognitive impairment and deterioration in global health for at least 6 months in patients with mild to moderate AD. Patients receiving active treatment will have more favorable ADAS-cog scores for at least 6 months, after which their scores will begin to converge with those of patients receiving placebo. Differences in methodology, types of direct or indirect costs included, and sources of cost data made it difficult to compare and synthesize findings of the economic studies; therefore, the cost-effectiveness data are inconclusive. [ABSTRACT FROM AUTHOR]

FT-IR and FT-Raman spectra of anethole (1-Methoxy-4-(1-propenyl)benzene), a flavoring agent of commercial value, have been recorded in the regions 4000-400 and 4000-100cm-1 respectively. The structure of the title molecule has been optimized and the structural parameters have been calculated by DFT/B3LYP method with 6-311++G(d,p) basis set. The fundamental vibrational wavenumbers as well as their intensities were calculated and a good agreement between observed and scaled calculated wavenumbers has been achieved. UV-Vis spectrum of the title compound was recorded in the region 200-500nm and the electronic properties such as HOMO and LUMO energies and associated energy gap were calculated by Time dependent-density functional theory (TD-DFT) approach. Nonlinear optical (NLO) study divulges the nonlinear properties of the molecule. Stability of the title molecule arising from hyper-conjugative interactions and charge delocalization has been investigated using natural bond orbital (NBO) analysis. The theoretical results were found to be in coherence with the measured experimental data. [ABSTRACT FROM AUTHOR]

Abstract: Comparative study of the optical properties of undoped and 3, 5, 7mol% MgO doped LiNbO3 crystals was undertaken. The effect of doping on refractive indices as well as second order susceptibility (SOS) has been experimentally analyzed. The comparison of 3, 5, 7mol% MgO doped LiNbO3 crystals show that the second order susceptibility has minimum at 5mol% MgO doping. MgO doping reduces the number of localized excitons and the grown LiNbO3 crystal approaches the stoichiometric composition. We also found that both the refractive indices (n o and n e) decrease due to MgO doping. It is observed that the blue shift in the cut off frequency occurred with increasing MgO doping concentration. [Copyright &y& Elsevier]

Undoped and MgO doped Lithium niobate single crystals were grown by the Czochralski technique. Comparative study of the optical properties of undoped and 7 mol% MgO doped LiNbO3 crystal was undertaken. The effect of doping on refractive indices as well as second harmonic generation has been experimentally analyzed. The results of the polarization characteristics of second harmonic generation (SHG) support the major contribution of Li–O bonds to optical nonlinearity. MgO doping reduces the number of localized excitons and the grown LiNbO3 crystal approaches the stoichiometric composition. This causes blue shift in the absorption edge of the crystals. [Copyright &y& Elsevier]

Background: Cancer arises through a multistep process, fuelled by deregulation of pathways in control of cellular growth and proliferation. The very same signalling cascades are targeted by infectious pathogens en route to subversion of the host to their benefit. One such pathogen--the bacterium Salmonella Typhi--is epidemiologically associated with an increased incidence of gallbladder carcinoma, as both are highly prevalent in India while relatively rare in the Western world. Methods & Materials: The present study demonstrates that Salmonella infection induces stable cellular transformation in pretransformed gallbladder organoids and mice. Inactivation of the TP53 pathway in combination with c-MYC oncogene amplification is minimal prerequisites for Salmonella-induced transformation in cell culture. Such alterations are also found to be prevalent in gallbladder carcinoma samples from India, relative to those derived from patients in the Netherlands. Results: In the infection process, Salmonella injects target cells with effector proteins that firstly activate the host's MAPK cascade during bacterial uptake, and secondarily turns on the AKT pathway to ensure intracellular bacterial survival. We found that both signalling pathways are activated in gallbladder carcinoma samples collected in India and are critical for maintaining the transformed state induced by Salmonella infection in cell culture. Conclusion: Collectively, our findings suggest that by virtue of manipulating host signalling for its own purposes, Salmonella promotes transformation in genetically predisposed cells as collateral damage, thus contributing to cancer in infected tissues, such as gallbladder. [ABSTRACT FROM AUTHOR]