Na,K-ATPase: a molecular target for Leptospira interrogans endotoxin

Independently conducted yet complementary sets of data from the 1970/1971 and 1990 National Jewish Population Surveys and the U.S. censuses of the same years were used to analyze changes in the internal migration of Jews and whites during the periods 1965-1970(1971) and 1985-1990. Interstate lifetime and five-year migration rates among Jews increased to levels significantly surpassing those of whites. Adjusting Jewish migration rates for the educational achievement of their white counterparts did not have much of an effect on lifetime migration or on the recent migration of the 1970/1971 Jewish population; however, it accounted meaningfully for the migration propensities of Jews in the period 1985-1990. These findings suggest that socioeconomic status has begun to play a larger role in promoting different migration patterns than in promoting ethnic group differences. Further, the direction of Jewish migrations followed those of whites (i.e., from the North-east and Midwest to the South and West): and due to their higher migration rates, Jews have considerably narrowed the regional distribution differences between themselves and whites. I interpret these results as evidence of the weakening role of ethnicity in present-day America.     

Effect of chronic administration of Ginkgo biloba extract or Ginkgolide on the hypothalamic-pituitary-adrenal axis in the rat

The hypersecretion of glucocorticoids during exposure to various stressors may induce or worsen pathological states in predisposed subjects. Therefore it is of interest to evaluate drugs able to reduce glucocorticoid secretion. It has recently been shown that chronic administration of a Ginkgo biloba extract (EGb 761) inhibits stress-induced corticosterone hypersecretion through a reduction in the number of adrenal peripheral benzodiazepine receptors. The present study was designed to analyze the effect of EGb 761 and one of its components, Ginkgolide B on the biosynthesis and secretion of CRH and AVP, the hypothalamic neurohormones that regulate the pituitary-adrenal axis. Chronic administration of EGb 761 (50 or 100 mg/kg p.o. daily for 14 days) reduced basal corticosterone secretion and the subsequent increase in CRH and AVP gene expression. Under the same conditions, surgically-induced increase in CRH secretion was attenuated while the activation of CRH gene expression, ACTH and corticosterone secretion following insulin-induced hypoglycemia remained unchanged. Chronic i.p. injection of Ginkgolide B reduced basal corticosterone secretion without alteration in the subsequent CRH and AVP increase. However, the stimulation of CRH gene expression by insulin-induced hypoglycemia was attenuated by Ginkgolide B. These data confirm that the administration of EGb 761 and Ginkgolide B reduces corticosterone secretion. In addition, these substances act also at the hypothalamic level and are able to reduce CRH expression and secretion. However the latter effect appears to be complex and may depend upon both the nature of stress and substance (Ginkgolide B or other compounds of EGb 761).     

Measurement of noise (cross-) power spectra for frequency-domainsystem identification purposes: large-sample results

Several frequency-domain estimators of parametric transfer function models assume that the (cross-) power spectra of the disturbing noise sources are known. This paper presents a time-efficient method to measure these noise (cross-) power spectra and studies its influence on the asymptotic properties of the estimated model parameters     

Noncontact critical dimension metrology sensor for chrome photomasks featuring a low-temperature co-fired ceramic technology

This paper describes a noncontact capacitive-sensor metrology sensor developed to measure minimum feature sizes, also called critical dimensions, patterned on photomasks that are used in semiconductor device manufacture. Additionally, this paper describes the test structures printed on photomasks that facilitate linewidth metrology with the new sensor. The metrology sensor is fabricated using a low temperature co-fired ceramic technology and its principle is based on noncontact microcapacitance measurements of features on chrome-on-glass reticles.     

Yielding behavior of prestrained interstitial-free steel and 70/30 brass

The yielding behavior of interstitial-free (IF) steel and 70/30 brass prestrained in plane strain tension and subsequently strained in uniaxial tension has been investigated experimentally. Upon reloading in uniaxial tension, brass exhibited a negative transient (decrease in flow stress) and steel exhibited a positive transient (increase in flow stress). When the yield stress is defined by the offset method, the positive transient is difficult to model using conventional yield theories as elastic deformation is thought to occur outside the original yield or loading surface. In this work, the yield point was defined using the axial strainvs transverse strain curve as measured with biaxial resistance strain gages. The curve has an initially linear elastic portion; the slope then gradually changes until the linear plastic slope is reached. The intersection of the elastic and plastic slopes is defined as the yield point. Using this alternate definition, the yielding behavior of the prestrained metals was investigated. The yield stress for both prestrained brass and steel was found to be lower than the expected monotonic stress. Compared to previous research based on a traditional definition of yield point, this result is unexpected in prestrained steel and shows that yielding does occur inside the loading surface. The positive transient may, therefore, be modeled using conventional yield theories provided that the yield surface is defined using this alternate technique.     

Separation and characterization of phenolic compounds in argan fruit pulp using liquid chromatography–negative electrospray ionization tandem mass spectroscopy

Liquid chromatography (LC) coupled to negative electrospray ionization (ESI) tandem mass spectrometry (MS/MS) was used for the sensitive identification of phenolic compounds in argan fruit pulp. Sixteen compounds were identified, mainly flavonoid glycosides and flavonoid aglycons.     

Mechanism of enhanced Na-K-ATPase activity in cortical collecting duct from rats with nephrotic syndrome

The maximal hydrolytic activity of Na-K-ATPase is specifically increased in the cortical collecting duct (CCD) of rats with puromycin-induced nephrotic syndrome (NS). This stimulation is independent of aldosterone and of endogenous ouabain-like substance. To investigate the mechanism responsible for this change, we compared the maximal Na-K-ATPase hydrolytic activity, the ouabain sensitive 86Rb influx, the specific [3H]ouabain binding, and the sensitivity of Na-K-ATPase to ouabain in the CCD of control rats and of rats given an intraperitoneal injection of puromycin 7 d before study. Both Na-K-ATPase activity and ouabain-sensitive 86Rb influx increased two-fold in rats with NS (ATPase activity: 34.1 +/- 2.1 vs. 18.0 +/- 0.7 pmol.mm-1 x min-1 +/- SE, n = 6, P < 0.001; Rb influx: 14.4 +/- 0.7 vs. 7.4 +/- 0.4 peq.min-1 +/- SE, n = 6, P < 0.001) whereas specific [3H]ouabain binding decreased in rats with NS (6.9 +/- 0.7 vs. 9.0 +/- 0.6 fmol.mm-1 +/- SE, n = 6, P < 0.005). Therefore, the maximal turnover rate of Na-K-ATPase increased over twofold in rats with NS (5,053 +/- 361 vs. 2,043 +/- 124 cycles.min-1 +/- SE, n = 6, P < 0.001). Analysis of the curves of inhibition of Na-K-ATPase by ouabain showed the presence of two Na-K-ATPase populations in both control and NS rats: a highly sensitive population (apparent Ki: 1.4 x 10(-6) M and 0.9 x 10(-6) M) and a less sensitive moiety (apparent Ki: 2.6 x 10(-4) M and 1.1 x 10(-4) M). The enhancement of Na-K-ATPase activity observed in the CCD of rats with NS was entirely due to the stimulation of the population of Na-K-ATPase with low ouabain sensitivity. These results suggest that a dysregulation of this subclass of Na-K-ATPase might be the primary cause of sodium retention in this model of nephrotic syndrome.     

Polarisation selective all-fibre Fabry-Perot filters with superimposed chirped Bragg gratings in high-birefringence fibres

Periodic highly birefringent filters with 50 and 100 GHz free spectral range and finesse of up to 20 are demonstrated. With a polarisation peak separation of 25 GHz, the polarisation crosstalk was measured to be less than -16 dB.