2,379 research outputs found

    Do Cues Matter? Highly Inductive Settlement Cues Don't Ensure High Post-Settlement Survival in Sea Urchin Aquaculture

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    Increasing settlement and post-settlement survival during the critical transition from planktonic larvae to benthic juveniles will increase efficiency for sea urchin aquaculture. This study investigated the effects of temperature and settlement cues on the settlement and post-settlement survival of the sea urchin Tripneustes gratilla during this phase. The current commercial methodology, which utilises natural biofilm settlement plates, was tested and resulted in low settlement (<2%) and poor post-settlement survival (<1% of settled urchins). In laboratory trials, settlement was high and unaffected by temperatures between 24 and 30°C, but significantly decreased at 33°C. Development of spines, however, was significantly affected by temperatures over 29°C. Mirroring this result, post-settlement survival was optimal between 24–28°C. In laboratory assays, the macroalgae Sargassum linearifolium and Corallina officinalis, and seawater conditioned with these algae, induced significantly higher settlement (>90%) than a natural biofilm (∼25%). The addition of macroalgae-conditioned seawater to natural biofilm significantly increased settlement rates (>85%). Mixed consortia and single strains of bacteria isolated from macroalgae, biofilms and adult conspecifics all induced significant settlement, but at significantly lower rates than macroalgae. No evidence was found that higher rates of settlement to bacteria on macroalgae were generated by a cofactor from the macroalgae. Age of bacterial cultures, culturing bacteria on solid and liquid media and concentration of nutrients in cultures had little effect on settlement rates. Finally, macroalgae-conditioned seawater combined with natural biofilm settlement plates induced significantly higher settlement than to the biofilm plates alone in a commercial scale trial. However, high post-settlement mortality resulted in equivalent survival between treatments after 25 days. This study highlights that settlement studies should extend to post-settlement survival, which remains poor for T. gratilla and is a significant obstacle to increasing efficiency for aquaculture

    Characteristics of non-fatal overdoses and associated risk factors in patients attending a specialist community-based substance misuse service

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    INTRODUCTION: There are concerns about rising drug-related deaths and the potential contribution of prescription analgesics. There is limited understanding regarding the role of prescription analgesics in non-fatal overdoses (NFODs), nor is there a good understanding of what factors are associated with more severe overdose. OBJECTIVES: To explore risk factors and characteristics of NFODs among people attending a specialist community-based substance misuse service. METHODS: After Caldicott approval, data on NFODs, in people attending the Tayside Substance Misuse Service (TSMS), were extracted from the Scottish Ambulance Service database, along with opioid replacement therapy (ORT) prescribing data. Statistical analysis was performed using R studio and Microsoft Excel. RESULTS: 557 people (78% [434/556] male, mean age ± standard deviation 38.4 ± 7.95) had an NFOD. Repeat NFODs were more likely in males compared to females (p < .0065). Males were more likely to be administered naloxone (OR = 1.94, 95% CI = 1.10–3.40, p < .02). NFODs at home were more likely to be moderate to severe (categorized by Glasgow Comma Scale [p < .02, OR = 4.95, 95% CI = 1.24–24.38]). Methadone (321/557, 57.63%), benzodiazepines (281/557, 50.45%) and heroin (244/557, 43.81%) were the commonest substances: prescribed methadone overdose was more likely than buprenorphine (p < .00001). Opioids and benzodiazepines were often taken together (275/557, 49.40%), with almost all gabapentinoid NFODs also involving opioids (60/61, 98.40%). CONCLUSIONS: Polysubstance use with opioids prescribed for ORT, such as methadone, is highly likely to be implicated in NFOD, with males being at the highest risk of severe and repeat NFOD. Future work should focus on strategies to further reduce NFODs

    Cell proliferation and differentiation kinetics during spermatogenesis in Hydra carnea

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    Spermatogenesis inHydra carnea was investigated. The cell proliferation and differentiation kinetics of intermediates in the spermatogenesis pathway were determined, using quantitative determinations of cell abundance, pulse and continuous labelling with3H-thymidine and nuclear DNA measurements. Testes develop in the ectoderm of male hydra as a result of interstitial cell proliferation. Gonial stem cells and proliferating spermatogonia have cell cycles of 28 h and 22 h, respectively. Stem cells undergo four, five or six cell divisions prior to meiosis which includes a premeiotic S+G2 phase of 20 h followed by a long meiotic prophase (22 h). Spermatid differentiation requires 12–29 h. When they first appear, testes contain only proliferating spermatogonia; meiotic and postmeiotic cells appear after 2 and 3 days, respectively and release of mature sperm begins after 4 days. Mature testes produce about 27,000 sperm per day over a period of 4–6 days: about 220 gonial stem cells per testis are required to support this level of sperm differentiation. Further results indicate that somatic (e.g. nematocyte) differentiation does not occur in testes although it continues normally in ectodermal tissue outside testes. Our results support the hypothesis that spermatogenesis is controlled locally in regions of the ectoderm where testes develop

    N/P ratio in the PEI2-GNP-DNA complex affects transgene delivery in the human cornea in vitro

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    Recently, we discovered that polyethylenimine-conjugated gold nanoparticles (PEI2- GNP) could be used as gene therapy vector for the cornea. It was hypothesized that DNA concentration, incubation timing and PEI monomer amount in transfection solution affect gene transfer efficiency and toxicity. The aims of this study were to test whether molar ratio of PEI2 nitrogen (N) and phosphate (P) of DNA in PEI2-GNP transfection solution regulates transgene delivery in human corneal fibroblasts in vitro, and examine PEI2-GNP toxicity, uptake and clearance for the cornea in vivo."National Eye Institute, NIH, Bethesda for RO1EY017294 (RRM), Diversity (RRM) and Veteran Health Affairs Merit (RRM) grants and Unrestricted grant from Research to Prevent Blindness, New York

    Arid3b Is Critical for B Lymphocyte Development

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    Arid3a and Arid3b belong to a subfamily of ARID (AT-rich interaction domain) transcription factors. The Arid family is involved in regulating chromatin accessibility, proliferation, and differentiation. Arid3a and Arid3b are closely related and share a unique REKLES domain that mediates their homo- and hetero-multimerization. Arid3a was originally isolated as a B cell transcription factor binding to the AT rich matrix attachment regions (MARS) of the immunoglobulin heavy chain intronic enhancer. Deletion of Arid3a results in a highly penetrant embryonic lethality with severe defects in erythropoiesis and hematopoietic stem cells (HSCs). The few surviving Arid3a-/- (<1%) animals have decreased HSCs and early progenitors in the bone marrow, but all mature lineages are normally represented in the bone marrow and periphery except for B cells. Arid3b-/- animals die around E7.5 precluding examination of hematopoietic development. So it is unclear whether the phenotype of Arid3a loss on hematopoiesis is dependent or independent of Arid3b. In this study we circumvented this limitation by also examining hematopoiesis in mice with a conditional allele of Arid3b. Bone marrow lacking Arid3b shows decreased common lymphoid progenitors (CLPs) and downstream B cell populations while the T cell and myeloid lineages are unchanged, reminiscent of the adult hematopoietic defect in Arid3a mice. Unlike Arid3a-/- mice, HSC populations are unperturbed in Arid3b-/- mice. This study demonstrates that HSC development is independent of Arid3b, whereas B cell development requires both Arid3a and Arid3b transcription factors

    Lateral Gene Expression in Drosophila Early Embryos Is Supported by Grainyhead-Mediated Activation and Tiers of Dorsally-Localized Repression

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    The general consensus in the field is that limiting amounts of the transcription factor Dorsal establish dorsal boundaries of genes expressed along the dorsal-ventral (DV) axis of early Drosophila embryos, while repressors establish ventral boundaries. Yet recent studies have provided evidence that repressors act to specify the dorsal boundary of intermediate neuroblasts defective (ind), a gene expressed in a stripe along the DV axis in lateral regions of the embryo. Here we show that a short 12 base pair sequence (“the A-box”) present twice within the ind CRM is both necessary and sufficient to support transcriptional repression in dorsal regions of embryos. To identify binding factors, we conducted affinity chromatography using the A-box element and found a number of DNA-binding proteins and chromatin-associated factors using mass spectroscopy. Only Grainyhead (Grh), a CP2 transcription factor with a unique DNA-binding domain, was found to bind the A-box sequence. Our results suggest that Grh acts as an activator to support expression of ind, which was surprising as we identified this factor using an element that mediates dorsally-localized repression. Grh and Dorsal both contribute to ind transcriptional activation. However, another recent study found that the repressor Capicua (Cic) also binds to the A-box sequence. While Cic was not identified through our A-box affinity chromatography, utilization of the same site, the A-box, by both factors Grh (activator) and Cic (repressor) may also support a “switch-like” response that helps to sharpen the ind dorsal boundary. Furthermore, our results also demonstrate that TGF-β signaling acts to refine ind CRM expression in an A-box independent manner in dorsal-most regions, suggesting that tiers of repression act in dorsal regions of the embryo

    Mental Toughness in South African Youth: Relationships With Forgivingness and Attitudes Towards Risk

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    Young people are particularly vulnerable to health risk behaviors and interpersonal violence, stimulating scholars’ attention towards identifying factors that may reduce the likelihood that these actions will occur. Associated with positive outcomes in a variety of domains, mental toughness in young people might protect them from engaging in potentially deleterious interpersonal or health-risk behaviors, while potentially promoting positive psychological behaviors. Within this framework, the present study investigated the relationships between mental toughness, attitudes towards physical and psychological risk-taking, and trait forgiveness in a sample of 123 (males = 54, females = 69) South African youth (M age = 23.97 years, SD = 4.46). Univariate and multivariate analyses indicated higher levels of mental toughness were associated with being more forgiving, (η2pηp2 = .036), perceiving physical risk-taking more positively (η2pηp2 = .062), but having more negative attitudes towards psychological risk-taking (η2pηp2 = .036). These findings give credence to mental toughness as a psychological characteristic involved in youth risk-taking perceptions and interpersonal functioning. Future research might explore the integration of mental toughness into the development of future youth risk behavior interventions

    Instruments to measure the ability to self-reflect:A systematic review of evidence from workplace and educational settings including health care

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    Introduction: Self-reflection has become recognised as a core skill in dental education, although the ability to self-reflect is valued and measured within several professions. This review appraises the evidence for instruments available to measure the self-reflective ability of adults studying or working within any setting, not just health care. Materials and Methods: A systematic review was conducted of 20 electronic databases (including Medline, ERIC, CINAHL and Business Source Complete) from 1975 to 2017, supplemented by citation searches. Data were extracted from each study and the studies graded against quality indicators by at least two independent reviewers, using a coding sheet. Reviewers completed a utility analysis of the assessment instruments described within included studies, appraising their reported reliability, validity, educational impact, acceptability and cost. Results: A total of 131 studies met the inclusion criteria. Eighteen were judged to provide higher quality evidence for the review and three broad types of instrument were identified, namely: rubrics (or scoring guides), self-reported scales and observed behaviour. Conclusions: Three types of instrument were identified to assess the ability to self-reflect. It was not possible to recommend a single most effective instrument due to under reporting of the criteria necessary for a full utility analysis of each. The use of more than one instrument may therefore be appropriate dependent on the acceptability to the faculty, assessor, student and cost. Future research should report on the utility of assessment instruments and provide guidance on what constitutes thresholds of acceptable or unacceptable ability to self-reflect, and how this should be managed
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