A graded index single quantum well bistable laser

The authors report the first implementation of a buried heterostructure DOES (double heterostructure optoelectronic switch), which incorporates the principles of graded-index, single-quantum-well (GRIN SQW) lasers. Continuous operation and a small signal optical bandwidth of 1.5 GHz were obtained when biased into the on-state. This is consistent with the bond pad side employed. This GRIN SQW DOES laser, fabricated in two-terminal BH form, has been shown to have properties commensurate with the growth and processing parameters employed. Although limited to two-terminal operation, performance is comparable to existing devices with similar designs     

The copper chaperone for superoxide dismutase

Copper is distributed to distinct localizations in the cell through diverse pathways. We demonstrate here that the delivery of copper to copper/zinc superoxide dismutase (SOD1) is mediated through a soluble factor identified as Saccharomyces cerevisiae LYS7 and human CCS (copper chaperone for SOD). This factor is specific for SOD1 and does not deliver copper to proteins in the mitochondria, nucleus, or secretory pathway. Yeast cells containing a lys7Delta null mutation have normal levels of SOD1 protein, but fail to incorporate copper into SOD1, which is therefore devoid of superoxide scavenging activity. LYS7 and CCS specifically restore the biosynthesis of holoSOD1 in vivo. Elucidation of the CCS copper delivery pathway may permit development of novel therapeutic approaches to human diseases that involve SOD1, including amyotrophic lateral sclerosis.     

Parental antecedents of adult codependency

Two aspects of codependency were investigated among 442 undergraduates. First, parental antecedents were examined by subjects completing measures of codependency, perceived parental dysfunctions (compulsivity, chemical dependency, and codependency), and parental styles (coercion, control, and non-nurturance). As expected, correlations between adult codependency and parental coercion, control, non-nurturance, and maternal compulsivity were significant. However, correlations between codependency and parental chemical dependency were not significant. A multiple regression analysis identified parental codependency and maternal coercion as significant predictors of subject codependency. To examine the second aspect of codependency, which assumes that codependency was identified over 40 years ago by Karen Horney, subjects completed a loss of self measure which correlated highly with codependency.     

Over one-half billion years of head conservation? Expression of an ems class gene in Hydractinia symbiolongicarpus (Cnidaria: Hydrozoa)

We report the isolation of an empty spiracles class homeodomain-containing gene, Cn-ems, from the hydrozoan Hydractinia symbiolongicarpus, the first gene of this class characterized in a lower metazoan. Cn-ems was found to be expressed in the head of gastrozooids, specifically in endodermal epithelial cells of the taeniolae of the hypostome. Cn-ems is not expressed in gonozooids, which lack taeniolae. Experimental conversion of the posterior region of the planula larva into head structures up-regulates expression of the gene. These findings establish that the association of ems-class genes with head structures preceded the evolution of bilateral symmetry.     

Reactive arthritis in patients attending an urban sexually transmitted diseases clinic

OBJECTIVE: To assess the prevalence, clinical manifestations, associated genital infections, and HLA associations of reactive arthritis (ReA) among patients attending an urban sexually transmitted diseases (STD) clinic. METHODS: Using a standardized questionnaire, 271 consecutive adults, primarily black, with possible or proven Chlamydia trachomatis genital infection were screened for symptoms of ReA. A followup questionnaire was administered 6 weeks later by mail. Patients who reported at least 1 symptom were evaluated by a rheumatologist. HLA-B typing was performed on patients with objective ReA features. RESULTS: Nine of 217 patients (4.1%) with genital infection/inflammation had objective ReA features. Chlamydial or nongonococcal STD syndromes were diagnosed in 8 of these 9 patients (88%). Genital infection/inflammation was asymptomatic in 78% of patients with ReA features. HLA-B27 or other B7-cross-reactive group antigens were not associated with the occurrence of ReA. CONCLUSION: Nongonococcal genital infections, often asymptomatic, can trigger a relatively mild ReA in a larger number of exposed patients than previously thought, irrespective of the individual's HLA status.     

The influence of occupational stress on construction professionals

The majority of the respondents were happy in their work but experienced considerable stress as a result of working practices, contractual arrangements and the demands of projects and their clients. Educationalists still retained their identity as 'construction lecturers' rather than as 'academic staff', and to some extent felt themselves to have the best of both worlds - the interest and variety of construction coupled with the satisfaction of acquiring and imparting knowledge and skills, as well as job security of 'academic tenure'.     

Fish response to modified flow regimes in regulated rivers: research methods,effects and opportunities

Globally, rivers are increasingly being subjected to various levels of physical alteration and river regulation to provide humans with services such as hydropower, freshwater, flood control, irrigation and recreation. Although river regulation plays an important role in modern society, there are potential consequences which may negatively affect fish and fish habitat. While much effort has been expended examining the response of fish to fluctuating flow regimes in different systems, there has been little in the way of a comprehensive synthesis. In an effort to better understand the effects of river regulation on fish and fish habitat, we conducted a systematic review of available literature with three goals: (1) summarize the various research methodologies used by regulated river researchers, (2) summarize the effects found on fish and fish habitat and (3) identify opportunities for future research. The results of the synthesis indicate that a wide variety of methodologies are being employed to study regulated river science, yet there is a gap in incorporating methodologies that examine effects on fish at a cellular level or those techniques that are interdisciplinary (e.g. behaviour and physiology). There is a clear consensus that modified flow regimes in regulated rivers are affecting fish and fish habitat, but the severity and direction of the response varies widely. Future study designs should include methods that target all biological levels of fish response, and in which detailed statistical analyses can be performed. There is also a need for more rigorous study designs including the use of appropriate controls and replicates. Data on physical variables that co‐vary with flow should be collected and examined to add explanatory power to the results. Increased multi‐stakeholder collaborations provide the greatest promise of balancing ecological concerns with economic needs. Copyright © 2008 John Wiley & Sons, Ltd.