Indications of selenium protection against cadmium toxicity in cultured K-562 cells

The interaction between selenium and cadmium was studied in relation to cellular uptake and expressions of selenium-cadmium interaction. Human K-562 cells were pre-treated or simultaneously treated with (5 or 50 microM) selenite or (10 or 50 microM) selenomethionine and with (60 or 75 microM) cadmium nitrate. Cells pre or simultaneously treated with selenite revealed increased cadmium concentration with increased doses of selenite, particularly pronounced in the simultaneous treatments. In both treatments, selenium protection was observed during the exposure period, but not during the growth period. In cells simultaneously treated with selenomethionine and 60-microM cadmium, an increase in cadmium concentration was observed after increased selenium dose. In addition, it was found that simultaneous selenomethionine treatment with 60-microM cadmium resulted in selenium protection during the exposure period, although protection was not observed during the growth period.     

Evidence of pyrene formation in butadiene–styrene-based rubber subjected to UV irradiation

A strong pyrene emission was observed when certain block, alternate, and random butadiene–styrene-based rubber films were subjected to intense UV irradiation in vacuum. Weak or no pyrene emission was obtained from the same films when they are irradiated in the presence of O₂. A mechanistic scheme leading to pyrene formation in these samples is given together with qualitative explanation of the dependence of pyrene formation on sample composition.     

A comparison of the extraction capacity of trioctylamine and its radiolytic products dioctylamine and primary octylamine for the elements U(VI), Mo(VI), Zr(IV) and Sr(II)

The percentage extraction of the elements U(VI), Mo(VI), Zr(IV) and Sr(II) from 1–6 M nitric acid by trioctylamine (TOA) and its radiolytic degradation products dioctylamine (DOA) and primary octylamine (POA) in xylene have been measured. TOA and DOA showed similar extraction capacities for Zr(IV), but DOA was less effective than TOA for U(VI) and Mo(VI), Sr(II) was not extracted by any of these amines. These results suggest that the use of the “Zirconium number” is in itself not sufficient when considering the resistance of TOA to radiation.     

Combining Digital Watermarks with Two-Color Bitmap Image

1 Introduction Digital media have made a big progress in the last few years, for the use of the digital media has many advantages compared with the analog media. The digital media are very easy to edit, copy and transmit over the networks. It is possible…     

Hydroxybenzaldoximes Are D‐GAP‐Competitive Inhibitors of E. coli 1‐Deoxy‐D‐Xylulose‐5‐Phosphate Synthase

1‐Deoxy‐D ‐xylulose 5‐phosphate (DXP) synthase is the first enzyme in the methylerythritol phosphate pathway to essential isoprenoids in pathogenic bacteria and apicomplexan parasites. In bacterial pathogens, DXP lies at a metabolic branch point, serving also as a precursor in the biosynthesis of vitamins B1 and B6, which are critical for central metabolism. In an effort to identify new bisubstrate analogue inhibitors that exploit the large active site and distinct mechanism of DXP synthase, a library of aryl mixed oximes was prepared and evaluated. Trihydroxybenzaldoximes emerged as reversible, low‐micromolar inhibitors, competitive against D ‐glyceraldehyde 3‐phosphate (D ‐GAP) and either uncompetitive or noncompetitive against pyruvate. Hydroxybenzaldoximes are the first class of D ‐GAP‐competitive DXP synthase inhibitors, offering new tools for mechanistic studies of DXP synthase and a new direction for the development of antimicrobial agents targeting isoprenoid biosynthesis.     

Numerical investigation of hydrothermal performance over perforated conical pin heat sinks

Over the past few decades, researchers have shown significant interest in enhancing the thermal efficiency of heat sinks while simultaneously increasing the power generation capacity of electronic devices and reducing their size. In this study, the focus lies on the originality of employing conical perforated pin heat sinks with multiple perforations (N = 0, 1, 2, and 3) and various conical pins inclination angles (Φ = 0°, 1°, 2°, 3°, and 4°). The study aimed to numerically investigate the effects of a perforated conical pin and cone inclination angle on heat transfer, pressure drop, CPU temperature, and hydrothermal performance (HTP) across the heat sinks using a three-dimensional, turbulent flow as k–ω SST model combined with the thermal conjugate model. A validated CFD model is employed to conduct a parametric analysis of the effects of the quantity and placement of circular holes. A summary of the results reveals that Model B3 exhibited the highest HTP value, reaching approximately 1.15 at U = 10 m/s, with a commendable reduction in heat sink mass of over 18%. Ultimately, the perforated conical pin heat sink demonstrates the potential to fulfill the primary objective of this investigation, which is achieving an overall improvement in Nusselt number, CPU temperature, pressure drop, and reduced heat sink mass.     

Wetting kinetics of polymer solutions and force‐based contact angles

The effect of the shear thinning behavior and elasticity of polymer solutions on the dynamic contact angles are investigated. Under dynamic conditions, the contact angle of a liquid on a solid surface changes significantly with the substrate velocity from its equilibrium value. The dynamic contact angles for polyethylene oxide (PEO) solutions of two molecular weights 3 × 10⁵ and 4 × 10⁶ have been measured using a polyethylene terephthalate (PET) plate. The three‐parameter Ellis model to fit the rheological data to obtain shear thinning power n, characteristic shear stress, and the zero‐shear viscosity is used. The theory indicates that dynamic contact angles follow power law in this instance instead of showing Newtonian behavior with zero‐shear viscosity when the shear thinning effects are considered. The elastic effect becomes important at larger polymer concentrations that reduces the dependence on capillary number, that is, reduces n keeping with the experiments. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2533–2541, 2016     

Evaluation of a transient test procedure for solar flat-plate collectors

A dynamic method for testing solar flat-plate collectors under unsteady weather conditions has been validated through detailed experiments and compared with two established standards: the ASHRAE 93–86 standard for steady state testing and the British standard BS 6757 for transient testing. The new method is based on a lumped capacity model derived from a general energy balance of the collector under actual conditions. The characteristic parameters are estimated using the standard methods for unconditional non-linear optimisation. Extensive experiments have been carried out under a wide range of operating and environmental conditions. Four different collectors commercially available in the market have been tested at the same location and using the same experimental rig. The results on the basis of the new method are very close to those obtained from the ASHRAE standard. The average values of F_R(τα)_e and F_RU_L by the new method are within ±3% of the steady state values. The results of the BS 6757 method are within ±2% for F_R(τα)_e but those of F_RU_L are about 12% lower than the ASHRAE values. On average, the difference between the theoretical predictions for the outlet temperature by the new method and the corresponding experimental measurements are about ±0.3°C, while the predictions by the British standard under the same conditions are about 2°C lower than measured values. The percentage deviations of predictions for the temperature rise based on the two methods, averaged over a day, are about ±8% and ±36% respectively. The new dynamic method requires less time for experimentation, one day's test is enough to give accurate estimation of the collector parameters. The method does not impose any restriction on the variation of weather or operating parameters and, therefore, has a quite general applicability.     

Chemical Modification of Guaran Gum Part I: Carboxymethylation in Aqueous Medium

Guar gum was isolated from the seeds and subjected to modification via carboxymethylation in aqueous medium. The modification increases its solubility in cold water, and increases the stability of its pastes to microorganisms. Regardless of the DS of these products, their aqueous solutions are characterized by non-Newtonian pseudoplastic behaviour, and their apparent viscosity at a constant rate of shear depends on the DS as well as the measuring temperature.     

Direct Derivatization vs Aqueous Extraction Methods of Fecal Free Fatty Acids for GC–MS Analysis

A comprehensive and accurate determination of free fatty acids (FFA) is required for fecal metabolomic investigations. The present study compares three aqueous extraction methods (1) ULTRA‐TURRAX^®, (2) whirl mixing and (3) basic ULTRA‐TURRAX extraction of fecal FFA with a direct derivatization approach using ethyl chloroformate as the derivatization reagent before determination by gas chromatography–mass spectrometry. The direct derivatization method resulted in significantly higher estimations (P < 0.01) of short‐ and long‐chain fatty acids than was the case when applying the aqueous extraction methods using ULTRA‐TURRAX, whirl mixing, or basic ULTRA‐TURRAX extraction before the derivatization step. Thus, avoiding an aqueous extraction before derivatization reduces the loss of volatile short‐chain FFA and the less water‐soluble long‐chain FFA.