Selenium deficiency as a model of experimental pre-eclampsia in rats

Epidemiological studies and in vitro analysis demonstrate correlations between selenium status and human pre-eclampsia (PET). Selenium is an essential component in the anti-oxidant proteins glutathione peroxidase and thioredoxin reductase, which are produced in lower amounts in pre-eclamptic placenta. This study examined the effect of modulating dietary selenium content in pregnant rats. Rats were fed diets containing no selenium, 239 microg/kg selenium or 1000 microg/kg selenium, four weeks prior to and following conception. Significant pregnancy-specific increases in systolic blood pressure (116.4 +/- 5.2 mmHg vs 108 +/- 6.8 mmHg vs 111.4 +/- 4.7 mmHg) and proteinuria (9.68 +/- 2.12 microg/ml vs 5.93 +/- 1.59 microg/ml vs 4.43 +/- 0.96 microg/ml) were demonstrated in animals fed a selenium free-diet when compared with normal or high selenium diets. Placental weight and pup number were not affected by selenium deprivation, however a significant decrease in the pup weight was evident. Selenium deprivation caused dose-dependent decreases in liver glutathione peroxidase (28.55 +/- 3.82 mmoles/min/mg vs 34.68 +/- 8.64 mmoles/min/mg) and thioredoxin reductase (2.37 +/- 1.25 U/mg vs 6.68 +/- 1.82 U/mg) activity, whereas superoxide dismutase activity remained constant. Placental activity of these enzymes also decreased leading to oxidative stress as measured by increased lipid peroxides (17.92 +/- 1.78 micromoles/mg vs 8.30 +/- 5.52 micromoles/mg) and protein carbonyls in tissue extracts from selenium-free animals. These results suggest that selenium deficiency in pregnant rats leads to symptoms similar to those seen in human PET and may provide an experimental model for studying this complex disease.     

Subjective responses to nicotine in smokers may be associated with responses to caffeine and to alcohol.

Sensitivity in responses to one drug may relate to sensitivity to other drugs, suggesting broad individual differences in characteristic responsivity across drugs. Data from two separate studies of smokers were reanalyzed to examine associations between acute subjective and cardiovascular effects of nicotine vs. caffeine and between nicotine vs. alcohol. Typical intakes of cigarettes, alcohol, and caffeine were included as covariates when they were correlated with the responses of interest. Significant associations between nicotine and caffeine were seen for most of the subjective measures and for blood pressure responses. Fewer significant associations were observed between nicotine and alcohol. Responses associated between nicotine and both of the other drugs tended to reflect psychomotor stimulation. These results suggest that smokers who are more responsive to some of nicotine's subjective and blood pressure effects are also more sensitive to the same effects of caffeine and, to a lesser extent, of alcohol. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Absolute Steady-State Thermal Conductivity Measurements by Use of a Transient Hot-Wire System

A transient hot-wire apparatus was used to measure the thermal conductivity of argon with both steady-state and transient methods. The effects of wire diameter, eccentricity of the wire in the cavity, axial conduction, and natural convection were accounted for in the analysis of the steady-state measurements. Based on measurements on argon, the relative uncertainty at the 95 % level of confidence of the new steady-state measurements is 2 % at low densities. Using the same hot wires, the relative uncertainty of the transient measurements is 1 % at the 95 % level of confidence. This is the first report of thermal conductivity measurements made by two different methods in the same apparatus. The steady-state method is shown to complement normal transient measurements at low densities, particularly for fluids where the thermophysical properties at low densities are not known with high accuracy.     

Thermochemotherapy Meets Tissue Engineering for Rheumatoid Arthritis Treatment

Rheumatoid arthritis (RA) is an autoimmune disease that progresses from inflammation to cartilage destruction. Inspired by the similar characteristics of inflammatory granulation tissue to those of tumors, the newly emerged tumor therapy called thermochemotherapy is proposed to treat RA. Meanwhile, the repair of cartilage injury via tissue engineering is paid attention simultaneously. A first-line antirheumatic drug (MTX; methotrexate) and transforming growth factor β1 (TGF-β1) are loaded in nano-Fe₃O₄ composite chitosan-polyolefin to construct a multifunctional hydrogel (DN-Fe-MTX-TGFβ1). The mechanical properties of the hydrogel are equivalent to that of articular cartilage to guarantee its role as a scaffold. A long-term release ability and the magnetocaloric properties of the hydrogel assure its effect to provide sustained local thermochemotherapy. The effective ability of the hydrogel for both anti-inflammation and cartilage repair is demonstrated. This work indicates a promising way to combine thermochemotherapy and tissue engineering for the effective treatment of RA for the first time.     

Control of the Electrical Properties in Spinel Oxides by Manipulating the Cation Disorder

In this work, the impact of cation disorder on the electrical properties of biaxially textured Co₂ZnO₄ and Co₂NiO₄ thin films grown by pulsed laser deposition are investigated using a combination of experiment and theory. Resonant elastic X‐ray diffraction along with conductivity measurements both before and after post‐deposition annealing show that Co₂ZnO₄ and Co₂NiO₄ exhibit opposite changes of the conductivity with cation disorder, which can be traced back to their different ground‐state atomic structures, being normal and inverse spinel, respectively. Electronic structure calculations identify a self‐doping mechanism as the origin of conductivity. A novel thermodynamic model describes the non‐equilibrium cation disorder in terms of an effective temperature. This work offers a way of controlling the conductivity in spinels in a quantitative manner by controlling the cation disorder and a new design principle whereby non‐equilibrium growth can be used to create beneficial disorder.     

Transport properties of refrigerants R32, R125, R134a, and R125+R32 mixtures in and beyond the critical regionPropriétés de transport des frigorigènes R32, R125, R134a et des mélanges de R125+R32 dans et au-delà la région critique

A practical representation for the transport coefficients of pure refrigerants R32, R125, R134a, and R125+R32 mixtures is presented which is valid in the vapor–liquid critical region. The crossover expressions for the transport coefficients incorporate scaling laws near the critical point and are transformed to regular background values far away from the critical point. The regular background parts of the transport coefficients of pure refrigerants are obtained from independently fitting pure fluid data. For the calculation of the background contributions of the transport coefficients in binary mixtures, corresponding-states correlations are used. The transport property model is compared with thermal conductivity and thermal diffusivity data for pure refrigerants, and with thermal conductivity data for R125+R32 mixtures. The average relative deviations between the calculated values of the thermal conductivity and experimental data are less than 4–5% at densities ρ0.1ρ_c and temperatures up to T=2T_c.