Characterization of endothelin-1 and nitric oxide generating systems in corpus luteum-derived endothelial cells

Endothelium-derived endothelin-1 (ET-1) and nitric oxide (NO) are pivotal regulators of corpus luteum (CL) function. To have a better insight into their synthesis and action, members of the ET system (ET-1, ET converting enzyme (ECE-1) isoforms a-d, ETA and ETB receptors) along with NO synthase (NOS) isoforms--endothelial (e)NOS and inducible (i)NOS--were quantified in CL-derived endothelial cells (CLEC). The expression of these genes in microvascular CLEC, obtained by lectin-coated magnetic beads, was compared with cells removed from the luteal microenvironment and maintained in culture for different durations, and with endothelial cells (EC) derived from a large blood vessel (i.e. bovine aortic endothelial cells, BAEC). The profile of gene expression in the different EC types was determined by quantitative real-time PCR. Freshly isolated EC from mid-cycle CL exhibited high ET-1 receptor expression (both ETA and ETB), low ET-1 synthesizing ability (both prepro (pp) ET-1 and ECE-1), but elevated iNOS - the high throughput NOS isoform. The distinct phenotype of CLEC was lost soon after an overnight culture. ETA and ETB receptor levels declined, ppET-1 levels increased while iNOS was reduced. These changes were extenuated during long-term culture of CLEC. The general pattern of gene expression in BAEC and long-term cultured CLEC was similar yet some differences, reminiscent of freshly isolated CLEC, remained: ECE-1c, ETB receptor and NOS isoforms were expressed differently in BAEC as compared with lines of CLEC. This study suggests that the luteal microenvironment is necessary to sustain the selective phenotype of its resident endothelial cells. The inverse relationship between ppET-1 and iNOS observed in freshly isolated CLEC and in cultured cells is physiologically significant and suggests that ET-1 and NO may modulate the production of each other.     

Enhancing creativity in an informal educational framework.

Studied the effects of a creativity-enhancing program in an experimental summer camp for disadvantaged children. The experimental group of 94 6th–7th graders spent 4 hrs/day in creativity games; the control group of 48 Ss participated in a regular recreational program. Two different creativity measures—the Torrance Tests of Creative Thinking and the Origence and Intellectual scales of the Welsh Figure Preference Test—were administered to all Ss at 3 different times: before treatment, after treatment, and in a 4-mo follow-up. Both after treatment and in the follow-up, the experimental group showed significantly higher scores than the control group. Results indicate resistance to extinction over time and are discussed in terms of content–context planning. (23 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Infant sleep and parental sleep-related cognitions.

Infant sleep is a major source of distress in many families. The purpose of this study was to assess infant sleep and parental sleep-related cognitions about infant sleep in clinical and control samples. The clinical sample consisted of 48 infants referred to a sleep clinic because of night-wakings problems. The control sample included 48 infants with no parental complaints about sleep difficulties. Sleep of all participating infants was monitored for 1 week with actigraphs and parental daily logs. Parents completed 2 questionnaires testing their cognitions about infant sleep. As expected, significant group differences were found with regard to the sleep-quality measures and parental cognitions. Parental cognitions about difficulties in limit setting were associated with poorer sleep quality. Significant differences were found between fathers and mothers on the cognitions scales. The results highlight the links between parental cognitions and infant sleep and the unique perspective of each parent in this area. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sunlight-mediated inactivation of MS2 coliphage via exogenous singlet oxygen produced by sensitizers in natural waters

Pathogens in sunlit surface waters can be damaged directly by UVB light. Indirect inactivation by reactive oxygen species (ROS) generated by sunlight interacting with external sensitizer molecules may also be important, but this mechanism has not been conclusively demonstrated. To better understand the role of ROS, we investigated the inactivation of MS2 coliphage, a commonly used surrogate for human enteric viruses, in water samples irradiated with a solar simulator and containing different types of sensitizers: waste stabilization pond (WSP) constituents, Fluka humic acid (FHA), and Suwannee River humic acid (SRHA). Inactivation of MS2 by the indirect mechanism was significant for all three sensitizers, and the efficiency of the sensitizers at inactivating MS2 was FHA > SRHA > WSP. Both dissolved and particulate fractions in the WSP water contributed to inactivation. In the WSP water, the indirect process was quantitatively more importantthan direct damage by UVB light, due to the rapid attenuation of UVB compared to the longer wavelengths that may initiate the indirect mechanism. Singlet oxygen (1O2) was the most important ROS involved in the inactivation of MS2. The addition of histidine, a 1O2 quencher, decreased inactivation, whereas inactivation rate constants increased in solutions of D20. Selective quenchers for other ROS showed little or no protective effect. Inactivation in WSP water was a function of the steady-state 102 concentration and could be described by a second-order rate expression.     

Molecular conduction through adlayers: cooperative effects can help or hamper electron transport

We use a one-electron, tight-binding model of a molecular adlayer sandwiched between two metal electrodes to explore how cooperative effects between molecular wires influence electron transport through the adlayer. When compared to an isolated molecular wire, an adlayer exhibits cooperative effects that generally enhance conduction away from an isolated wire's resonance and diminish conductance near such a resonance. We also find that the interwire distance (related to the adlayer density) is a key quantity. Substrate-mediated coupling induces most of the cooperative effects in dense adlayers, whereas direct, interwire coupling (if present) dominates in sparser adlayers. In this manner, cooperative effects through dense adlayers cannot be removed, suggesting an optimal adlayer density for maximizing conduction.     

A coupled model tree (MT) genetic algorithm (GA) scheme for biofouling assessment in pipelines

A computerized learning algorithm was developed for assessing the extent of biofouling formations on the inner surfaces of water supply pipelines. Four identical pipeline experimental systems with four different types of inlet waters were set up as part of a large cooperative project between academia and industry in Israel on biofouling modeling, prediction, and prevention in pipeline systems. Samples were taken periodically for hydraulic, chemical, and biological analyses. Biofilm sampling was done using Robbins devices, carrying stainless steel coupons. An MT-GA, a hybrid model combining model trees (MTs) and genetic algorithms (GAs) in which the sampled input data are selected by the proposed methodology, was developed. The method outcome is a set of empirical linear rules which form a model tree, iteratively optimized by a GA and verified using the dataset resulting from the empirical field studies. Good correlations were achieved between modeled and observed cell coverage area within the biofilm. Sensitivity analysis was conducted by testing the model’s response to changes in: (1) the biofilm measure used as output (target) variable; (2) variability of GA parameters; and (3) input attributes. The proposed methodology provides a new tool for biofouling assessment in pipelines.     

Framework for using quantitative PCR as a nonculture based method to estimate virus infectivity

Measuring the efficiency of virus disinfection with quantitative PCR (qPCR) has been criticized as inadequate due to the production of false-positive signals. Such a claim, however, presupposes an understanding of the theoretical qPCR response. Many studies have assumed that the loss in qPCR signal upon disinfection should equal the loss in infectivity, without accounting for the fact that qPCR typically assays only a fraction of the viral genome. This study aimed to develop a theoretical framework to relate viral infectivity with genome damage measured by qPCR. The framework quantified damage to the entire genome based on the qPCR amplification of smaller sections, assuming single-hit inactivation and a Poissonian distribution of damage. The framework was tested and modified using UV(254) inactivation studies with bacteriophage MS2 (culturing and qPCR of approximately half the genome). Genome regions showed heterogeneous sensitivities to UV(254) treatment, thus deviating from the assumption of Poissonian damage. We offered two modifications to account for these deviations and confirmed that the qPCR-based framework accurately estimated virus infectivity. This framework offers the potential to monitor the infectivity of viruses that remain nonculturable (norovirus). While developed for UV(254)-inactivated virus, the framework should apply to any disinfection technique that causes inactivation via single genomic lesions.     

Reactivity of substituted benzotrichlorides toward granular iron, Cr(II), and an iron(II) porphyrin: A correlation analysis

Cross-correlations of rate constants between a system of interest and a better-defined one have become popular as a tool in studying transformations of organic pollutants. A slope of unity (if the correlation is conducted on a log-log basis) in such plots has been invoked as evidence of a common mechanism. To explore this notion, benzotrichloride and several of its substituted analogues were reacted with Cr(H2O)6(2+), an iron(II) porphyrin (iron meso-tetra(4-carboxyphenyl)porphine chloride, Fe(II)TCP), and granular iron. The first two reductants react with organohalides by dissociative inner sphere single-electron transfer, while mechanism(s) for organohalide reduction by granular iron are still debated. Apartfrom sterically hindered compounds, good correlations were obtained in comparing any two systems, although slopes (on a log-log basis) deviated from unity. We argue that a slope of unity is neither necessary nor sufficient evidence of a common mechanism. Overall rate constants may be composite entities, consisting in part of rate or equilibrium constants for adsorption onto surfaces or for precursor formation in solution; these components may differ between systems in their susceptibility to substituent effects. Cross-correlations may prove useful in predicting reactivity in the absence of steric effects, but additional evidence is required in deducing reaction mechanisms.     

Size selectivity during dip coating of sol–gel silica-based antireflective coatings and its effect on the porosity of the coatings

The behavior of the particle size distribution (PSD) during the preparation of sol–gel silica-based antireflective coatings (ARCs) by dip coating was examined. It was found that the PSD after deposition differs dramatically from the PSD in the sol–gel suspensions, with the PSD after deposition being much narrower. A correlation between a decrease in the porosity of the ARC and an increase in the dispersity of the deposited PSD was also found. Hence, controlling the PSD during deposition has a direct effect on the resulting porosity and thus on the reflectance of an ARC. It was found that the temperature and deposition speed during dip coating, respectively, have very little effect on the deposited PSD. It was found that the PSD of the sol–gel suspension control the content of the deposited PSD, but does not change the range of sizes deposited. Finally, it was found that random-uniform particle placement results in elongated sequences of four or more particles, which supports our previous conclusion that the linear permittivity mixing rule is most appropriate for Stöber-based ARCs.