Reduced vascular beta-adrenergic receptors and catecholamine response in rats with lead induced hypertension

Beta-adrenergic receptor-mediated relaxation of blood vessels declines in lead induced hypertension although the mechanism is unknown. We have utilized the aorta of lead hypertensive rats to investigate this problem. In an effort to elucidate the mechanism responsible for this alteration we examined plasma catecholamine levels, vascular beta-adrenergic receptor density, and cyclic adenosine monophosphate (cAMP) production in lead hypertensive rats. The density of beta-adrenergic receptors was 41% lower in the blood vessels of lead hypertensive rats compared with control rats. The corresponding apparent Kd values were not significantly different between two groups. The plasma catecholamine level was significantly higher in lead hypertensive rats compared with controls (P < 0.001). Stimulation of the vascular beta-adrenoceptor resulted in significantly lower levels of cAMP in lead hypertensive rats compared with controls (P < 0.001). The present results suggest that there is reduced beta-adrenoceptor density and diminished cAMP accumulation in blood vessels from lead hypertensive rats. Plasma catecholamine may play a role in the diminished beta-adrenoceptor and responsiveness to cAMP-mediated vascular relaxation in lead exposure.     

New diagnosis approach to epoxy resin transformer partial discharge using acoustic technology

This paper first investigates the correlation between acoustic signals and electric power-source signal angles using ultrasonic detection technique. This paper then compares said acoustic signals' three-dimensional patterns with their polar-coordinate patterns and, with angle-zones established, provides a new analyzing and identification method for partial discharge (PD) fault types. This method is applicable to field inspection and measurement and can help identify epoxy-resin transformers' PD fault types. We first produce specific PD fault types in the laboratory and receive PD signals using ultrasonic technique. Then, we adopt polar-coordinate patterns to analyze their characteristics, deduce said characteristics into zone-identification patterns, and apply the D parameters to identify fault types. After utilizing this analyzing method to field epoxy-resin transformers, we learn that its diagnosis ability is fine and effective.     

Ammonium chloride alters renal tubular cell growth and protein turnover

1. Toxicokinetics of pentachloroanisole (PCA) were studied in F344 rat and B6C3F1 mouse of both sexes by gavage at doses of 10, 20 and 40 mg/kg and by i.v. at 10 mg/kg. 2. PCA was rapidly demethylated to pentachlorophenol (PCP) in both rat and mouse and the resulting PCP plasma concentrations were much higher than that of parent PCA due to the much smaller apparent volume of distribution of PCP. 3. Peak plasma concentrations of PCA and PCP increased with dose in both rat and mouse. 4. Bioavailability of PCA was low in both rat and mouse and was sex independent. 5. The high plasma concentrations and relatively long biological half-life of PCP in both species after both i.v. and oral dosing with PCA indicate possible bioaccumulation of PCP upon multiple oral administrations of PCA.     

The effect of fluorine on MOSFET channel length

The effect of fluorine on MOS device channel length has been evaluated. Fluorine has been introduced into the transistor by self-aligned ion implantation after the lightly doped drain (LDD) implant. The impact of fluorine in the LDD region, and its effect on the electrically determined channel length (L_eff), has been examined. Measurements taken from 0.6-μm LDD MOSFETs show a significant dependence of the L_eff on fluorine implant dose. The n⁺ resistor also shows more width reduction compared to unfluorinated samples. The decrease in channel length reduction by adding fluorine in the LDD region may yield way to relieve short-channel effects for the continuous scaling of CMOS devices into the deep-submicrometer region     

Frequency-Weighted Minimum-Variance Adaptive Control of Laser Beam Jitter

This paper introduces a frequency-weighting method for adaptive disturbance rejection. The method constrains the high-frequency gain of the prediction filter in a minimum-variance adaptive controller. In an experimental application, the method is used to control a microelectromechanical system fast steering mirror to suppress laser beam jitter. The paper analyzes the effect of sensor noise on the performance of the adaptive control system and demonstrates that sufficient levels of high-frequency noise and/or disturbance combined with control saturation produce a spiking phenomenon in the output error. The experimental results show that the frequency weighting eliminates the spiking.     

Microstructures and mechanical behaviors of Mg58Cu31Gd11 and Mg65Cu25Gd10 amorphous alloys synthesized by injection casting and melt spinning

Mg₅₈Cu₃₁Gd₁₁ and Mg₆₅Cu₂₅Gd₁₀ alloys were synthesized via two processing routes, injection casting and melt spinning. The diameter of the injection-cast bars was 4 mm in diameter. The XRD results obtained for the Mg₅₈Cu₃₁Gd₁₁ are nearly identical to those for the Mg₆₅Cu₂₅Gd₁₀, showing amorphous-like broad characteristic peaks. All the four characteristic temperatures, T_g, T_x, T_m and T_l, of the Mg₆₅Cu₂₅Gd₁₀ are essentially lower than those of Mg₅₈Cu₃₁Gd₁₁, for both injection-cast rods and melt-spun ribbons. The glass forming abilities of the Mg₆₅Cu₂₅Gd₁₀ are similar to those of Mg₅₈Cu₃₁Gd₁₁, for both injection-cast rods and melt-spun ribbons, indicated by T_rg = 0.60 and γ = 0.42. The average microhardness of the Mg₆₅Cu₂₅Gd₁₀ is 2.41 GPa and 2.27 GPa for injection-cast bars and melt-spun ribbons, respectively, which are significantly lower than 2.84 GPa and 2.49 GPa of the Mg₅₈Cu₃₁Gd₁₁. The nanohardness at the maximum load from the multiple loading is 3.5 GPa for Mg₆₅Cu₂₅Gd₁₀, which is lower than 3.9 GPa for Mg₅₈Cu₃₁Gd₁₁. The curves of load vs. the depth obtained from the nanoindentation tests all show stepwise behavior due to the pop-in events, and the step width increases as the indentation rate decreases. The modulus at the maximum load from the multiple loading obtained from the nanoindentation tests is 64.9 GPa for Mg₆₅Cu₂₅Gd₁₀, which is lower than 70.7 GPa for Mg₅₈Cu₃₁Gd₁₁. The fracture stress and strain of the Mg₆₅Cu₂₅Gd₁₀ BMG rod at room temperature are 490 MPa and 3%, respectively, smaller than those of the Mg₅₈Cu₃₁Gd₁₁ BMG rod, 548 MPa and 3.2%, respectively. The Mg₅₈Cu₃₁Gd₁₁ BMG rod is stronger at room temperature, and also shows higher yield stress and less deformable at elevated temperature, than the Mg₆₅Cu₂₅Gd₁₀ BMG rod.     

Simple stability criteria for nonlinear time-varying discrete systems

We present two sufficient conditions for asymptotic stability of nonlinear time-varying discrete systems. Our main results generalize Mori's result for linear discrete time-invariant systems to nonlinear time-varying systems.     

Low-delay subband CELP coding for wideband speech

Low-delay techniques are proposed for coding 7 kHz speech using subband code-excited linear predictive coding (CELP). The use of separate and joint index codebooks is compared. Specifically, the joint-index-subband CELP (JISBC) algorithm is found to provide good quality with processing delay in the range 2.375-3.375 ms at corresponding bit rates of 16-8 kbit/s     

Acoustic analysis of lexical tone in Mandarin infant-directed speech.

Using Mandarin Chinese, a "tone language" in which the pitch contours of syllables differentiate words, the authors examined the acoustic modifications of infant-directed speech (IDS) at the syllable level to test 2 hypotheses: (a) the overall increase in pitch and intonation contour that occurs in IDS at the phrase level would not distort lexical pitch at the syllable level and (b) IDS provides exaggerates cues to lexical tones. Sixteen Mandarin-speaking mothers were recorded while addressing their infants and addressing an adult. The results indicate that IDS does not distort the acoustic cues that are essential to word meaning at the syllable level; evidence of exaggeration of the acoustic differences in IDS was observed, extending previous findings of phonetic exaggeration to the lexical level. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Characterization of KC60Obtained via a Potassium Carbonate Route

KC_6o synthesized by high temperature annealing of mixture of C₆₀ and K₂C0₃has been characterized by EPR, NMR and differential scanning calorimetry methods. The rich phase diagram with polymeric and dimer phases previously elaborated for KC₆₀ is obtained in present work as well. This suggests that alkaline carbonates can be efficiently used in preparation of C₆₀-based polymer materials where C_6o molecules are charged by alkaline atoms. Another important outcome of present study is that despite high temperatures and presence of oxygen released from K₂CO₃, EPR and NMR spectra did not exhibit signals which might be referred to fullerene epoxides or related species.