The study of the changes in the thermal properties of <Emphasis Type="Italic">Labeo rohita</Emphasis> bones due to arsenic exposure

The paper presents the changes in the thermal properties of control, arsenic exposed and DMSA treated Labeo rohita bones by using thermo analytical techniques. The result shows that the mass loss due to the thermal decomposition occurs in three distinct steps due to loss of water, organic and inorganic materials. The arsenic exposed bones present a different thermal behaviour compared to the control bones. The residue masses are increased due to arsenic exposure, while the DMSA treatment reduces the residue mass level. These thermal characteristics can be used as a qualitative method to check the metal accumulation in samples.     

Tuning the excitonic and plasmonic properties of copper chalcogenide nanocrystals

The optical properties of stoichiometric copper chalcogenide nanocrystals (NCs) are characterized by strong interband transitions in the blue part of the spectral range and a weaker absorption onset up to ~1000 nm, with negligible absorption in the near-infrared (NIR). Oxygen exposure leads to a gradual transformation of stoichiometric copper chalcogenide NCs (namely, Cu(2-x)S and Cu(2-x)Se, x = 0) into their nonstoichiometric counterparts (Cu(2-x)S and Cu(2-x)Se, x > 0), entailing the appearance and evolution of an intense localized surface plasmon (LSP) band in the NIR. We also show that well-defined copper telluride NCs (Cu(2-x)Te, x > 0) display a NIR LSP, in analogy to nonstoichiometric copper sulfide and selenide NCs. The LSP band in copper chalcogenide NCs can be tuned by actively controlling their degree of copper deficiency via oxidation and reduction experiments. We show that this controlled LSP tuning affects the excitonic transitions in the NCs, resulting in photoluminescence (PL) quenching upon oxidation and PL recovery upon subsequent reduction. Time-resolved PL spectroscopy reveals a decrease in exciton lifetime correlated to the PL quenching upon LSP evolution. Finally, we report on the dynamics of LSPs in nonstoichiometric copper chalcogenide NCs. Through pump-probe experiments, we determined the time constants for carrier-phonon scattering involved in LSP cooling. Our results demonstrate that copper chalcogenide NCs offer the unique property of holding excitons and highly tunable LSPs on demand, and hence they are envisaged as a unique platform for the evaluation of exciton/LSP interactions.     

Diels–Alder modification of poly(ethylene terephthalate‐co‐anthracene‐2,6‐carboxylate) with N‐substituted maleimides

Dimethyl 2,6‐anthracene dicarboxylate is used as a comonomer in the synthesis of functional copolymers that are subject to modification with Diels–Alder reactions. The formation of poly(ethylene terephthalate‐co‐2,6‐anthracenate), containing less than 20 mol % of the anthracene‐2,6‐dicarboxylate structural units, provides materials that are tractable and soluble. The anthracene units of the copolymers undergo Diels–Alder reactions with N‐substituted maleimides. The grafting of N‐alkylmaleimides affords soluble, hydrophobic polymers, whereas grafting with maleimide‐terminated poly(ethylene glycol) affords hydrophilic polymers. Because this reaction proceeds below the melting point of the copolymers, the procedure can be applied to thin films, whereby the surface properties are modified. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3256–3263, 2002     

Routine analysis by high precision gas chromatography/mass selective detector/isotope ratio mass spectrometry to 0.1 parts per mil

Stable isotope methods are potentially quite useful for validating natural or enhanced mineral degradation of contaminants. For this reason, a continuous flow gas chromatograph (GC), isotope ratio mass spectrometer (IRMS) has been coupled with a quadrupole mass selective detector (MSD) to allow simultaneous mass spectral and stable carbon isotope ratio data to be obtained from a single chromatographic analysis. This allows the target contaminant and any extra-cellular degradation intermediates to be both qualified and quantified. Previously acceptable limits of precision (0.3 parts per mil) are undesirable given the small fractionation observed during aerobic degradation. To further understand the fate of organic contaminants and to gain information about the metabolic degradative pathway employed by a microorganism, routine isotopic analyses on a range of analytes have been performed. Quantities of sample producing mass-44 ion beam signal (I(44)) of 2 x 10(-10) to 1 x 10(-8) A were analysed. When the IRMS was tuned for high sensitivity, ion source nonlinearities were overcome by peak height correction from an algorithm that was produced using known isotopic standards of varying concentrations. This led to sample accuracy of <0.01 per thousand and sample precision of 0.1 per thousand. Copyright 1999 John Wiley & Sons, Ltd.     

Frequency scan for the analysis of high mass ions generated by matrix-assisted laser desorption/ionization in a paul trap

An ion trap has been modified for the analysis of high mass ions generated by matrix-assisted laser desorption/ionization. Samples are deposited on a probe tip and introduced directly onto the hyperbolically shaped surface of one endcap. All three electrodes - both the endcaps and the ring electrode - are insulated so that the radio frequency (Rf) voltage may be applied to the center ring electrode and the inverted Rf voltage to the endcaps. By using low frequencies (below 100 kHz) and low amplitudes (below 200 V), high mass singly charged ions may be trapped and analyzed by a frequency sweep at constant amplitude. In the high mass range (60-160 kDa), this instrument showed good sensitivity, signal-to-noise ratios, and mass resolution. Copyright 1999 John Wiley & Sons, Ltd.     

Formation of the ω Phase in the Titanium—Iron System under Shear Deformation

JETP Letters - The effect of the phase composition on the α/β-Ti(Fe)→ω-Ti(Fe) transformation in the Ti-4 wt % Fe alloy under shear strain with high-pressure torsion (HPT) has...     

An alternative approach to deal with geometric uncertainties in computer analysis of two-dimensional electrophoresis gels

With the growing importance of proteomics in biomedical and pharmaceutical sciences a need has emerged for computing tools that are capable of digitally visualizing and analyzing protein spot patterns within two-dimensional electrophoresis (2-DE) gel. Matching programs need to meet requirements such as interlaboratory comparison and the comparison of samples from different origins. For such research purposes, we have developed the CAROL system that implements new algorithms for spot detection and matching, which enable researchers to take a different approach to protein spot identification and comparison. The present short communication discusses how the system deals with uncertain geometric spot information that arises from streaks and complex spot regions and how this can be amplified for the matching procedure.     

K + p andK − p elastic scattering at 32.1 GeV/c

Results are presented onK ⁺ p andK ^? p elastic scattering at 32.1 GeV/c in the |t| interval 0.06–1.4 GeV². The samples contain approximately 15,000 events each and are obtained in the MIRABELLE bubble chamber at the Serpukhov accelerator. The |t| distributions are parametrized by quadratic exponential formsdσ/dt=A exp (bt+ct ²). The total elastic cross sections, obtained by integrating the fitted distributions, are (2.39±0.07) mb and (2.57±0.10) mb inK ⁺ p andK ^? p interactions, respectively. A cross-over between theK ⁺ p andK ^? p differential cross sections is found at |t _c |=0.17±0.02 GeV². The hypothesis of geometric scaling becomes valid somewhere between 32 and 70 GeV/c forK ⁺ p interactions, and is trivially verified forK ^? p scattering. Finally, an impact parameter analysis of the difference betweenK ^? p andK ⁺ p elastic amplitudes is presented.     

An advanced gas/vapor permeation system for barrier materials: Design and applications to poly(ethylene terephthalate)

A new gas/vapor mixture permeation system is described to investigate the effect of organic molecules on oxygen (O₂) and carbon dioxide (CO₂) transport in barrier materials. Methanol vapor was considered as a flavor simulant mainly because of its conveniently high diffusion coefficient, which makes the experimental time accessible. A highly accurate syringe pump was used to introduce a desired activity level of vapor into gas feed stream. Adsorption of methanol on high energy surfaces is carefully characterized to prevent underestimation of methanol permeability. A special permeation cell was also developed to study the effect of interacting vapors on O₂ and CO₂ transport in barrier materials. Systematic permeation measurements were conducted for binary and ternary gas/vapor permeation measurements (e.g., MeOH/O₂ and O₂/CO₂/MeOH) to verify the feasibility of our new vapor/gas permeation system. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012