Higher nicotine and carbon monoxide levels in menthol cigarette smokers with and without schizophrenia.

This study examined whether smoking menthol cigarettes was associated with increased biochemical measures of smoke intake. Expired carbon monoxide (CO) and serum nicotine and cotinine were measured in 89 smokers with schizophrenia and 53 control smokers immediately after smoking an afternoon cigarette. Serum nicotine levels (27 vs. 22 ng/ml, p = .010), serum cotinine levels (294 vs. 240 ng/ml, p = .041), and expired CO (25 vs. 21 ppm, p = .029) were higher in smokers of menthol compared with nonmenthol cigarettes, with no differences in 3-hydroxycotinine/cotinine ratios between groups when controlling for race. Backward stepwise linear regression models showed that, in addition to having a diagnosis of schizophrenia, smoking menthol cigarettes was a significant predictor of nicotine and cotinine levels. Individuals with schizophrenia or schizoaffective disorder smoked more generic or discount value brands (Basic, Doral, Monarch, USA, Wave, others) compared with control smokers (28% vs. 6%, p = .002) but did not smoke more brands with high nicotine delivery as estimated by the U.S. Federal Trade Commission method. Although rates of mentholated cigarette smoking were not higher in smokers with schizophrenia overall, they were significantly higher in non-Hispanic White people with schizophrenia compared with controls of the same ethnic/racial subgroup (51% vs. 28%, p<.0001). The higher exhaled CO in menthol smokers suggests that the higher nicotine levels are at least partly related to increased intake of smoke from menthol cigarettes, although menthol-mediated inhibition of nicotine metabolism also may be a factor. Menthol is an important cigarette additive that may help explain why some groups have lower quit rates and more smoking-caused disease.     

On the optimal design of the PML absorbing boundary condition forthe FDTD code

An analytical method to predict and optimize the performance of Berenger's (see J. Computat. Phys., vol.114, p.185-200, 1994) perfectly matched layer (PML) absorbing boundary condition (ABC) for finite-difference time-domain (FDTD) simulations is described. The shape of the conductivity in the PML layers has to be chosen carefully to obtain the best performance for a given number of layers. The relative error is shown to be the composite of two distinct effects: the theoretical reflection coefficient given by the PML layers backed by a metal plane and the second-order error in the differential intrinsic in the FDTD formulation. A theoretical expression to evaluate this error as a function of the number of PML layers and the shape of the conductivity is given, and the result is compared to that obtained for several FDTD test cases. The good agreement of the shapes of the theoretical and numerically derived curves allows the use of the theoretical formulation to optimize the PML region as a function of the shape of the conductivity, resolution, and number of layers     

Thermopower of YBa2Cu3O7-δ–Ag Composites

The percolation behavior of normal-state thermopower, resistivity, and superconductivity have been studied in YBa₂Cu₃O_7-δ─Ag (YBCO─Ag) composite systems. The normal-state resistivity and thermopower show a percolation threshold at a Ag volume fraction ( V _Ag) of 20% to 30%, whereas the superconducting network shows a threshold at a V _Ag of ≅70% to 80%. The results obtained from this study show that the YBCO─Ag composite obtained from Ag₂O and YBCO powders is uniformly distributed with Ag and YBCO remaining as separate phases without changing their characteristics. The measurements of thermopower indicate that the normal-state thermopower and phonon-drag thermopower are affected by the Ag addition. The stability of YBCO is increased when it is in composite form.     

Structure‐Guided Design of Thiazolidine Derivatives as Mycobacterium tuberculosis Pantothenate Synthetase Inhibitors

The pantothenate biosynthetic pathway is essential for the persistent growth and virulence of Mycobacterium tuberculosis (Mtb) and one of the enzymes in the pathway, pantothenate synthetase (PS, EC: 6.3.2.1), encoded by the panC gene, has become an appropriate target for new therapeutics to treat tuberculosis. Herein, we report nanomolar thiazolidine inhibitors of Mtb PS developed by a rational inhibitor design approach. The thiazolidine compounds were discovered by using energy‐based pharmacophore modelling and subsequent in vitro screening, which resulted in compounds with a half maximal inhibitory concentration (IC₅₀) value of (1.12±0.12) μM . These compounds were subsequently optimised by a combination of modelling and synthetic chemistry. Hit expansion of the lead by chemical synthesis led to an improved inhibitor with an IC₅₀ value of 350 nM and an Mtb minimum inhibitory concentration (MIC) of 1.55 μM . Some of these compounds also showed good activity against dormant Mtb cells.     

Onset conditions for a Rayleigh–Taylor instability with step function density profiles

The stability of several density profiles constructed from a linear combination of step functions in a vertically orientated two-dimensional porous medium are considered. A quasi-steady-state approximation is made so that the initial stability of the system can be approximated. Using a similar approach to that of Tan and Homsy (Phys Fluids 29:3549–3556, 1986) a dispersion equation for each density profile is obtained analytically at time zero. Neutral stability curves are then obtained to allow the regions of the parameter space to be divided into stable and unstable regions.     

Enhanced photocatalytic activity of sulfur doped TiO2 for the decomposition of phenol: A new insight into the bulk and surface modification

Sulfur ion (S⁶⁺) was doped into the anatase TiO₂ prepared by sol–gel method (SG-TiO₂) using sulfur powder as a sulfur source (S-TiO₂) and its photoreactivity was probed for the degradation of phenol under UV/solar light illumination. The S-TiO₂ and SG-TiO₂ were characterized by PXRD, UV–vis DRS, FTIR, SEM, XPS, BET and PL techniques. It was observed that S⁶⁺ ion was incorporated into the TiO₂ crystal lattice at Ti⁴⁺ lattice site and the sulfur on the surface gets modified to ₄SO²⁻${{\text{SO}}_4}^{2-}$ due to the heat treatment under atmospheric conditions. The high photocatalytic activity of S-TiO₂ compared to SG-TiO₂ is attributed to the surface modification of sulfur as sulfate which plays a crucial role in trapping electrons. S-TiO₂ shows significant increase in the surface area, reduced crystallite size, increased surface acidity, visible light absorption and prolonged lifetime of the photogenerated charge carriers. Hole scavengers like potassium iodide and tertiary butanol suggested the surface degradation mechanism rather than the bulk degradation pathway. Addition of oxidizing agents to the degradation reaction did not show any enhancement in the degradation rates since the presence of ₄SO²⁻${{\text{SO}}_4}^{2-}$ on the TiO₂ surface itself acts as the efficient electron trapping centers. Both trapping and detrapping of the electron takes place more efficiently at ₄SO²⁻${{\text{SO}}_4}^{2-}$ centers. The enhanced activity of S-TiO₂ is attributed to the synergistic effect between S⁶⁺ dopant with surface modified ₄SO²⁻${{\text{SO}}_4}^{2-}$.     

Basic investigation of HfO2 based metal-insulator-metal diodes

Very fast frequency response of metal-insulator-metal (MIM) diodes extends into the terahertz regime making them attractive as key elements as alternative to photovoltaic solar energy harvesting and ultrahigh speed wireless communication systems. The tunnelling phenomena, which is crucial for achieving high performance in these devices is extremely sensitive to the nanoscale structural and chemical quality of interface regions. Modern chemical deposition techniques like Pulsed Injected Metal-Organic Chemical Vapour Deposition (PICVD), Atomic Layer Deposition (ALD) and Atomic Vapour Deposition (AVD®) will be used for the extremely precise growth of thin HfO₂ films on TiN bottom electrodes. However, different deposition techniques may give unpredictably different results in terms of film density, surface and interface property and consequently in physical properties of the device.In this work, the influence of deposition techniques on the charge transport characteristics of HfO₂ MIM diodes was investigated by Conducting Atomic Force Microscopy (C-AFM) and X-ray Photoelectron Spectroscopy (XPS).     

A novel nanostructured iron oxide-gold bioelectrode for hydrogen peroxide sensing

Fe(3)O(4) nanoparticles covalently linked to a gold electrode have been used for immobilizing catalase (CAT) enzyme to sense the presence of various concentrations of H(2)O(2). These nanoparticles ranging from 20 to 30 nm were synthesized by thermal co-precipitation of ferric and ferrous chlorides. SEM and XRD have been used for morphological and structural characterization of Fe(3)O(4) nanoparticles. CAT enzyme was linked covalently to the surface of iron oxide using carbodiimide in phosphate buffer (pH 7.4) at 4?°C. The enzyme-iron oxide link was confirmed by FT-IR spectroscopy. Sensing studies carried out using cyclic voltammetry showed a linear response of the CAT/nano Fe(3)O(4)/Au bioelectrode towards H(2)O(2) between 1.5 and 13.5 μM with a very sharp response time of 2 s.     

Effect of simultaneous double doping in Ba and Ti sites on dielectric and ferroelectric properties of sol–gel synthesized nano-BaTiO<Subscript>3</Subscript>

Lead free (Ba_(1−3x)Nd_(2x))(Ti_(1−y)Zr_y)O₃ (x = 0, 0.025, y = 0, 0.025, 0.05) ceramics were prepared successfully using sol–gel method. The effect of Nd, Zr content on dielectric and polarisation properties of BaTiO₃ were studied using dielectric and hysteresis measurements. SEM analysis proved that the particle size of compounds as prepared were in the order of 30–60 nm. The ferroelectric phase transition from tetragonal to cubic phase was observed around 130 °C for pure BaTiO₃. With the addition of Nd (2.5 mol%) and increasing content of Zr (2.5 and 5 mol%), it was observed that transition temperature (T_c) shifts to lower temperatures (70–50 °C), but didn’t show any relaxor behaviour. Dielectric measurements showed an increase in the values at room temperature in all the doped samples. The synthesized ceramics exhibited typical P–E hysteresis loops at room temperature accompanied by saturation polarisation (P_s) and remanent polarisation (P_r). Behaviour of polarisation phenomena in these compounds showed interesting results with increasing temperature.     

UV reactor flow visualization and mixing quantification using three-dimensional laser-induced fluorescence

Three-dimensional laser-induced fluorescence (3DLIF) was applied to visualize and quantitatively analyze mixing in a lab-scale UV reactor consisting of one lamp sleeve placed perpendicular to flow. The recirculation zone and the von Karman vortex shedding that commonly occur in flows around bluff bodies were successfully visualized. Multiple flow paths were analyzed by injecting the dye at various heights with respect to the lamp sleeve. A major difference in these pathways was the amount of dye that traveled close to the sleeve, i.e., a zone of higher residence time and higher UV exposure. Paths away from the center height had higher velocities and hence minimal influence by the presence of sleeve. Approach length was also characterized in order to increase the probability of microbes entering the region around the UV lamp. The 3DLIF technique developed in this study is expected to provide new insight on UV dose delivery useful for the design and optimization of UV reactors.