135 research outputs found

    Minimum Thermal Conductivity of Superlattices

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    The phonon thermal conductivity of a multilayer is calculated for transport perpendicular to the layers. There is a cross over between particle transport for thick layers to wave transport for thin layers. The calculations shows that the conductivity has a minimum value for a layer thickness somewhat smaller then the mean free path of the phonons.Comment: new results added, to appear in PR

    Efficacy and Safety of an Injectable Combination Hormonal Contraceptive for Men

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    CONTEXT: The development of a safe and effective reversible method of male contraception is still an unmet need. OBJECTIVE: Evaluation of suppression of spermatogenesis and contraceptive protection by coadministered im injections of progestogen and testosterone. DESIGN: Prospective multicentre study. SETTING: Ten study centers. PARTICIPANTS: Healthy men, aged 18-45 years, and their 18- to 38-year-old female partners, both without known fertility problems. INTERVENTION: Intramuscular injections of 200-mg norethisterone enanthate combined with 1000-mg testosterone undecanoate, administered every 8 weeks. MAIN OUTCOMES MEASURES: Suppression of spermatogenesis by ejaculate analysis, contraceptive protection by pregnancy rate. RESULTS: Of the 320 participants, 95.9 of 100 continuing users (95% confidence interval [CI], 92.8-97.9) suppressed to a sperm concentration less than or equal to 1 million/mL within 24 weeks (Kaplan-Meier method). During the efficacy phase of up to 56 weeks, 4 pregnancies occurred among the partners of the 266 male participants, with the rate of 1.57 per 100 continuing users (95% CI, 0.59-4.14). The cumulative reversibility of suppression of spermatogenesis after 52 weeks of recovery was 94.8 per 100 continuing users (95% CI, 91.5-97.1). The most common adverse events were acne, injection site pain, increased libido, and mood disorders. Following the recommendation of an external safety review committee the recruitment and hormone injections were terminated early. CONCLUSIONS: The study regimen led to near-complete and reversible suppression of spermatogenesis. The contraceptive efficacy was relatively good compared with other reversible methods available for men. The frequencies of mild to moderate mood disorders were relatively high

    The Regulation of MS-KIF18A Expression and Cross Talk with Estrogen Receptor

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    This study provides a novel view on the interactions between the MS-KIF18A, a kinesin protein, and estrogen receptor alpha (ERα) which were studied in vivo and in vitro. Additionally, the regulation of MS-KIF18A expression by estrogen was investigated at the gene and protein levels. An association between recombinant proteins; ERα and MS-KIF18A was demonstrated in vitro in a pull down assay. Such interactions were proven also for endogenous proteins in MBA-15 cells were detected prominently in the cytoplasm and are up-regulated by estrogen. Additionally, an association between these proteins and the transcription factor NF-κB was identified. MS-KIF18A mRNA expression was measured in vivo in relation to age and estrogen level in mice and rats models. A decrease in MS-KIF18A mRNA level was measured in old and in OVX-estrogen depleted rats as compared to young animals. The low MS-KIF18A mRNA expression in OVX rats was restored by estrogen treatment. We studied the regulation of MS-KIF18A transcription by estrogen using the luciferase reporter gene and chromatin immuno-percipitation (ChIP) assays. The luciferase reporter gene assay demonstrated an increase in MS-KIF18A promoter activity in response to 10−8 M estrogen and 10−7M ICI-182,780. Complimentary, the ChIP assay quantified the binding of ERα and pcJun to the MS-KIF18A promoter that was enhanced in cells treated by estrogen and ICI-182,780. In addition, cells treated by estrogen expressed higher levels of MS-KIF18A mRNA and protein and the protein turnover in MBA-15 cells was accelerated. Presented data demonstrated that ERα is a defined cargo of MS-KIF18A and added novel insight on the role of estrogen in regulation of MS-KIF18A expression both in vivo and in vitro

    Secondary Metabolites of Marine Microbes: From Natural Products Chemistry to Chemical Ecology

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    Marine natural products (MNPs) exhibit a wide range of pharmaceutically relevant bioactivities, including antibiotic, antiviral, anticancer, or anti-inflammatory properties. Besides marine macroorganisms such as sponges, algae, or corals, specifically marine bacteria and fungi have shown to produce novel secondary metabolites (SMs) with unique and diverse chemical structures that may hold the key for the development of novel drugs or drug leads. Apart from highlighting their potential benefit to humankind, this review is focusing on the manifold functions of SMs in the marine ecosystem. For example, potent MNPs have the ability to exile predators and competing organisms, act as attractants for mating purposes, or serve as dye for the expulsion or attraction of other organisms. A large compilation of literature on the role of MNPs in marine ecology is available, and several reviews evaluated the function of MNPs for the aforementioned topics. Therefore, we focused the second part of this review on the importance of bioactive compounds from crustose coralline algae (CCA) and their role during coral settlement, a topic that has received less attention. It has been shown that certain SMs derived from CCA and their associated bacteria are able to induce attachment and/or metamorphosis of many benthic invertebrate larvae, including globally threatened reef-building scleractinian corals. This review provides an overview on bioactivities of MNPs from marine microbes and their potential use in medicine as well as on the latest findings of the chemical ecology and settlement process of scleractinian corals and other invertebrate larvae

    Put It in Your Shoe It Will Make You Limp: British Men’s Online Responses to a Male Pill

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    The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.This article analyzes online interactions between British men and other online readers’ comments in response to two news articles focused on a male contraceptive pill. The aim of the study was to explore how British men’s online accounts construct a male pill as a potential contraceptive option for family planning. The two online articles reported the scientific innovations, as well as the production and marketing, of a nonhormonal, plant-based pill for men. Discourse analysis was used to analyze the online comments, from which two discourses emerged: (a) “Men as responsible health consumers” and (b) “‘Killing sperm’ and other side effects on semen.” When provided with the opportunity to take future responsibility for family planning, male readers were found to be unlikely to use a contraceptive pill. The men expressed the need for new options of contraception but, overall, felt a male pill was not the solution
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