Is urine leukocyte esterase test a useful screening method to predict Chlamydia trachomatis infection in women?

We evaluated the use of the leukocyte esterase test (LET) on first-catch urine specimens from women as a screening test to predict infection with Chlamydia trachomatis. For diagnosis, we used Abbott's ligase chain reaction (LCR) on urine specimens and isolation by tissue culture (TC) on cervical brushes. Of 4,053 women attending sexually transmitted disease and family planning clinics, 4.3% (n = 174) were positive by TC and 5.9% (n = 239) were positive by LCR. When LET was compared to TC, the sensitivity, specificity, positive predictive value, and negative predictive value were 54.0, 67.0, 6.8, and 97.0%, respectively. The corresponding performance of LET versus LCR was 53.1, 67.3, 10.1, and 95.8%. Almost half of the laboratory-confirmed chlamydial infections were negative by LET. The low specificity probably reflects multiple causes of pyuria in women and results in a low positive predictive value. LET is neither sensitive nor specific as a predictor of chlamydial infection and cannot be recommended for use as a screening test for C. trachomatis with first-catch urine samples from females from low- or moderate-prevalence populations.     

Organic geochemistry of heavy/extra heavy oils from sidewall cores, Lower Lagunillas Member, Tia Juana Field, Maracaibo Basin, Venezuela

The study of 22 oils from sidewall cores taken at different depths in the Lower Lagunillas Member, well LSJ-AB, Tia Juana Field, Maracaibo Lake is presented, with the purpose of predicting the intervals that present the best crude oil quality. Differences were detected in the biodegradation levels of the studied samples, which are correlated with the depth at which the sidewall core was taken. The API gravity was considered for the oils from each sidewall core and it was found that toward the top of the sequence, the oils have an API gravity of 10.6-11.2°, while toward the base part of the sequence, the well produces extra heavy oils with an API gravity that varies between 8.2 and 8.7°.     

Crack-like formation of failure-decided angle points on middle planes of the layers resistant to bending in multi-layer structure - a continuum model

A theoretical model is considered that describes, in a continuum approximation, formation of a segment of angle points on the middle planes of thin layers forming a multi-layer structure. These points are associated with the jumps of the slope of the middle planes on the segment. A 2-D case is dealt with. The structure is assumed to be a half-plane with its boundary parallel to the layers and acted upon by a symmetric distribution of the displacements normal to the boundary. The layers forming the structure are assumed capable of mutually gliding with respect to each other and of revealing their flexure rigidity under the above loading. The continuum approximation to describe the above multi-layer structure has been applied. Physically the above mathematical angle points may (depending on the layer material properties) emerge either as a result of transverse fracture of the layers or as a result of intensive local plastic deformation (formation of the plastic `hinges'). As a result, the bending moment drops drastically, so that it is assumed dropping down to zero. This condition is employed to determine the distribution of the above slope jumps. The segment length is determined by equating the bending moment at the remote (from the boundary) end of the segment to a critical (specified) value of the bending moment. Thus, the problem of determining the slope jumps on the segment is reduced to a Fredholm integral equation of the first kind with the kernel having an integrable singularity. This equation has been solved numerically. The results of the calculations are presented.     

Surface chemistry of tribochemical reactions explored in ultrahigh vacuum conditions

The thermal decomposition of model extreme-pressure lubricant additives on clean iron was studied in ultrahigh vacuum conditions using molecular beam strategies. Methylene chloride and chloroform react to deposit a solid film consisting of FeCl₂ and carbon, and evolve only hydrogen into the gas phase. No gas-phase products and less carbon on the surface are detected in the case of carbon tetrachloride. Dimethyl and diethyl disulfide react on clean iron to deposit a saturated sulfur plus carbon layer at low temperatures (∼600 K) and an iron sulfide film onto a Fe + C underlayer at higher temperatures (∼950 K). Methane is the only gas-phase product when dimethyl disulfide reacts with iron. Ethylene and hydrogen are detected when diethyl disulfide is used.     

Prenatal development of intrafetal and maternal-fetal synchrony.

Fetal and maternal data were monitored serially at 6 gestational ages from 20 to 38 weeks in 195 Peruvian fetuses. Digitized data included fetal heart rate and motor activity, as well as maternal heart rate and electrodermal conductance. Time series analysis evaluated the development of synchrony in 2 streams of fetal functioning and between mothers and fetuses. Intrafetal synchrony between heart rate and motor activity developed in an orderly fashion, with peak cross-correlation approaching an asymptote at 5 s at 28 weeks. Synchrony was not observed between fetal heart rate and maternal measures. Fetal motor activity exhibited synchrony with both maternal electrodermal and heart rate activity. Implications for revealing fundamental properties of neural development prior to birth are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Material constant sensitivity boundary integral equation for anisotropic solids

In this paper, the material constant sensitivity boundary integral equation is presented, and its numerical solution proposed, based on boundary element techniques. The formulation deals with plane problems with general rectilinear anisotropy. Expressions for the computation of sensitivities for displacements, tractions, strains and stresses are derived, both for boundary and interior points. The sensitivities can be computed with respect to the bulk material properties or to the properties of part of the domain (inclusions, coatings, etc.). To assess the accuracy of the proposed approach, the computed results are compared to analytical ones derived from exact solutions obtained by complex potential theory, when possible, or finite difference derivatives otherwise. Copyright © 2005 John Wiley & Sons, Ltd.     

Nitrergic neurotransmission mediates the non-adrenergic non-cholinergic responses in the clitoral corpus cavernosum of the rabbit

The corpus cavernosum is the erectile tissue in the penis and clitoris. Although nitrergic neurotransmission has been characterized in detail in the penile corpus cavernosum, functional studies on the inhibitory non-adrenergic non-cholinergic (NANC) transmission in the clitoral corpus cavernosum have been lacking. Here we demonstrate that electrical field stimulation (EFS) induces NANC relaxation responses in the clitoral corpus cavernosum of the rabbit. These responses were inhibited by NG-nitro-L-arginine methylester (L-NAME), 1H-[1,2,4]oxadiazolo[4,3,-a]quinoxalin-1-one (ODQ) or tetrodotoxin. The inhibitory effect of L-NAME was partially reversed by L-arginine but not by D-arginine. EFS-induced relaxations were enhanced by an inhibitor of type V cyclic GMP phosphodiesterase, zaprinast. These results suggest that nitrergic neurotransmission is responsible for the NANC relaxation responses in the clitoral corpus cavernosum of the rabbit.     

On formalism and stability of switched systems

In this paper,we formulate a uniform mathematical framework for studying switched systems with piecewise linear partitioned state space and state dependent switching.Based on known results from the the...