1,088 research outputs found
Ruppia maritima seed and Thalassia testudinum seedling responses to fluctuations in salinity and ammonium
Six species of seagrasses are present in Florida Bay ranging from stenohaline to euryhaline species. The dominant species, Thalassia testudinum Banks ex. König, has optimum growth around marine salinity. The second species examined in this study was Ruppia maritima L, which tends to grow near fresh water outflows. Although many studies have examined the responses of mature plants to environmental stresses, this study examined the impacts on seeds and seedlings. As the focus behind the study was altered water flow into Florida Bay, it examined hypo- and hyper-salinity, as well as depleted and elevated ammonium concentrations. This study was conducted in mesocosms on material collected in Florida Bay. R. maritima seed germination and T. testudinum seedling survival, growth, photosynthesis and osmolality were investigated over a two-year study. Year one focused on direct introductions into hyper- and hypo-saline conditions and year two examined the impact of gradual increase/decrease in salinity as well as the addition of ammonium. R. maritima seeds did not germinate above 28 PSU and the highest percent germination occurred between 0 and 10 PSU. Elevated levels of ammonium decreased germination. Hypo-saline conditions were, however, detrimental to the fitness of T. testudinum seedlings, as were hyper-saline conditions. Plants at 0 and 70 PSU showed 100% mortality and decreased survival in the 60, 50 and 10 PSU treatments. Increased levels of ammonium decreased growth in the lower salinity treatments. Plants grown around 30-40 PSU showed the greatest growth (i.e. most productivity). Measurements of quantum yields as well as relative electron transport rate using PAM fluorometry showed a decrease in photosynthetic performance on either side of this 30-40 PSU optimum. Tissue osmolality increased significantly with increased salinity and tissue remained distinctly and consistently hyperosmotic to the media. Results suggest that a change in fresh water flow as well as possible increase in ammonium may negatively impact the ability of T. testudinum seedlings to establish and possibly cause a shift in the floral composition of Florida Bay, favoring euryhaline species such as Ruppia maritima
Reaching for the 'first 95': a cross-country analysis of HIV self-testing in nine countries in sub-Saharan Africa
OBJECTIVES: HIV self-testing (HIVST) offers a promising approach to increase HIV diagnosis and advance progress towards the UNAIDS 95-95-95 targets. We aimed to understand patterns of HIVST awareness and utilization in nine sub-Saharan African (SSA) countries, with the goal of identifying populations to target in disseminating this technology. DESIGN: A cross-sectional study. METHODS: We pooled individual-level population-based data from nine Demographic and Health Surveys (DHS) in SSA conducted 2015-2019 (Burundi, Cameroon, Guinea, Malawi, Senegal, Sierra Leone, South Africa, Zambia, Zimbabwe). Primary outcomes were HIVST awareness and utilization. We used logistic regression with survey fixed effects to explore the relationship between sociodemographic characteristics and these outcomes. Models were adjusted for sex, age, rural/urban residence, education, wealth, and marital status. We accounted for complex survey design. RESULTS: The study sample included 177 572 people (66.0% women, mean age 29 ± 10 years), of whom 86.6% [95% confidence interval (95% CI) 86.4-86.7] were unaware of HIVST, 11.7% (95% CI 11.6-11.9) were aware of but never used HIVST, and 1.7% (95% CI 1.6-1.8) had used HIVST. In adjusted models, women were less likely to be aware of HIVST [odds ratio (OR) 0.75, 95% CI 0.71-0.79], but more likely to have used HIVST (OR 1.17, 95% CI 1.03-1.32) compared with men. Rural residents, those who were least educated, and poorest were less likely to have heard of or used HIVST. CONCLUSION: HIVST awareness and uptake were low. Rural, less educated, and lower income populations were least likely to have heard of or used HIVST. Efforts to scale-up HIVST in these settings should aim to reach these less advantaged groups
Protein Conformation and Supercharging with DMSO from Aqueous Solution
The efficacy of dimethyl sulfoxide (DMSO) as a supercharging reagent for protein ions formed by electrospray ionization from aqueous solution and the mechanism for supercharging were investigated. Addition of small amounts of DMSO to aqueous solutions containing hen egg white lysozyme or equine myoglobin results in a lowering of charge, whereas a significant increase in charge occurs at higher concentrations. Results from both near-UV circular dichroism spectroscopy and solution-phase hydrogen/deuterium exchange mass spectrometry indicate that DMSO causes a compaction of the native structure of these proteins at low concentration, but significant unfolding occurs at ~63% and ~43% DMSO for lysozyme and myoglobin, respectively. The DMSO concentrations required to denature these two proteins in bulk solution are ~3–5 times higher than the concentrations required for the onset of supercharging, consistent with a significantly increased concentration of this high boiling point supercharging reagent in the ESI droplet as preferential evaporation of water occurs. DMSO is slightly more basic than m-nitrobenzyl alcohol and sulfolane, two other supercharging reagents, based on calculated proton affinity and gas-phase basicity values both at the B3LYP and MP2 levels of theory, and all three of these supercharging reagents are significantly more basic than water. These results provide additional evidence that the origin of supercharging from aqueous solution is the result of chemical and/or thermal denaturation that occurs in the ESI droplet as the concentration of these supercharging reagents increases, and that proton transfer reactivity does not play a significant role in the charge enhancement observed
Variations in risk assessment models may contribute to the existing gap between venous thromboembolism prophylaxis guidelines and adherence
Are there Social Spillovers in Consumers’ Security Assessments of Payment Instruments?
Even though security of payments has long been identified as an important aspect of the consumer payment experience, recent literature fails to appropriately assess the extent of social spillovers among payment users. We test for the existence and importance of such spillovers by analyzing whether social influence affects consumers’ perceptions of the security of payment instruments. Based on a 2008–2014 annual panel data survey of consumers, we find strong evidence of social spillovers in payment markets: others’ perceptions of security of payment instruments exert a positive influence on one’s own payment security perceptions. The significant and robust results imply that a consumer’s assessments of security converge to his peers’ average assessment: a 10 percent change in the divergence between one’s own security rating and peers’ average rating will result in a 7 percent change in one’s own rating in the next period. The results are robust to many specifications and do not change when we control for actual fraud or crime data. Our results indicate that spillovers rather than reflection appear to be the cause, although separating the two causes is very difficult (Manski 1993). In particular, the spillovers are stronger for people who experience an exogenous shock to security perception, people who have more social interactions, and younger consumers, who are more likely to be influenced by social media. We also examine the effects of social spillovers on payment behavior (that is, on decisions regarding payment adoption and use). Our results indicate that social spillovers have a rather limited impact on payment behavior, as others’ perceptions seem to affect one’s own payment behavior mainly indirectly through the effect on one’s own perceptions
Vascular responses of the extremities to transdermal application of vasoactive agents in Caucasian and African descent individuals
This is an accepted manuscript of an article published by Springer in European Journal of Applied Physiology on 04/04/2015, available online: https://doi.org/10.1007/s00421-015-3164-2
The accepted version of the publication may differ from the final published version.© 2015, Springer-Verlag Berlin Heidelberg. Purpose: Individuals of African descent (AFD) are more susceptible to non-freezing cold injury than Caucasians (CAU) which may be due, in part, to differences in the control of skin blood flow. We investigated the skin blood flow responses to transdermal application of vasoactive agents. Methods: Twenty-four young males (12 CAU and 12 AFD) undertook three tests in which iontophoresis was used to apply acetylcholine (ACh 1 w/v %), sodium nitroprusside (SNP 0.01 w/v %) and noradrenaline (NA 0.5 mM) to the skin. The skin sites tested were: volar forearm, non-glabrous finger and toe, and glabrous finger (pad) and toe (pad). Results: In response to SNP on the forearm, AFD had less vasodilatation for a given current application than CAU (P = 0.027–0.004). ACh evoked less vasodilatation in AFD for a given application current in the non-glabrous finger and toe compared with CAU (P = 0.043–0.014) with a lower maximum vasodilatation in the non-glabrous finger (median [interquartile], AFD n = 11, 41[234] %, CAU n = 12, 351[451] %, P = 0.011) and non-glabrous toe (median [interquartile], AFD n = 9, 116[318] %, CAU n = 12, 484[720] %, P = 0.018). ACh and SNP did not elicit vasodilatation in the glabrous skin sites of either group. There were no ethnic differences in response to NA. Conclusion: AFD have an attenuated endothelium-dependent vasodilatation in non-glabrous sites of the fingers and toes compared with CAU. This may contribute to lower skin temperature following cold exposure and the increased risk of cold injuries experienced by AFD.Published versio
Revising the WHO verbal autopsy instrument to facilitate routine cause-of-death monitoring.
OBJECTIVE: Verbal autopsy (VA) is a systematic approach for determining causes of death (CoD) in populations without routine medical certification. It has mainly been used in research contexts and involved relatively lengthy interviews. Our objective here is to describe the process used to shorten, simplify, and standardise the VA process to make it feasible for application on a larger scale such as in routine civil registration and vital statistics (CRVS) systems. METHODS: A literature review of existing VA instruments was undertaken. The World Health Organization (WHO) then facilitated an international consultation process to review experiences with existing VA instruments, including those from WHO, the Demographic Evaluation of Populations and their Health in Developing Countries (INDEPTH) Network, InterVA, and the Population Health Metrics Research Consortium (PHMRC). In an expert meeting, consideration was given to formulating a workable VA CoD list [with mapping to the International Classification of Diseases and Related Health Problems, Tenth Revision (ICD-10) CoD] and to the viability and utility of existing VA interview questions, with a view to undertaking systematic simplification. FINDINGS: A revised VA CoD list was compiled enabling mapping of all ICD-10 CoD onto 62 VA cause categories, chosen on the grounds of public health significance as well as potential for ascertainment from VA. A set of 221 indicators for inclusion in the revised VA instrument was developed on the basis of accumulated experience, with appropriate skip patterns for various population sub-groups. The duration of a VA interview was reduced by about 40% with this new approach. CONCLUSIONS: The revised VA instrument resulting from this consultation process is presented here as a means of making it available for widespread use and evaluation. It is envisaged that this will be used in conjunction with automated models for assigning CoD from VA data, rather than involving physicians
Are hospitals delivering appropriate VTE prevention? The venous thromboembolism study to assess the rate of thromboprophylaxis (VTE start)
The 7th conference of the American College of Chest Physicians (ACCP7) provides recommendations on the type, dose, and duration of thromboprophylaxis in hospitalized patients at risk of venous thromboembolism (VTE), but the extent to which hospitals follow these criteria has not been well studied. Discharge and billing records for patients admitted to any of 16 acute-care hospitals from January 2005 to December 2006 were obtained. Patients 18 years or older who had an inpatient stay ≥2 days and no apparent contraindications for thromboprophylaxis were grouped into the categories of critical care, surgery and medically ill before being assessed for additional VTE risk factors based on the diagnostic criteria outlined in ACCP7. For patients at risk, the recommended type (mechanical or pharmacologic), dose, and duration of thromboprophylaxis was identified based on the guidelines and compared to the regimen actually received, if any. Among the 258,556 hospitalized patients, 68,278 (26.4%) were determined to be at risk of VTE without apparent contraindications for thromboprophylaxis. The proportions of patients who received the appropriate type, dose, and duration of thromboprophylaxis were 10.5, 9.8, and 17.9% for critical care, medical, and surgical patients, respectively. Of those at risk, 36.8% received no thromboprophylaxis and an additional 50.2% received thromboprophylaxis deemed inappropriate for one or more reasons. The implementation of ACCP7 guidelines for type, dosage, and duration of thromboprophylaxis is low in patients at risk of VTE. There is a need for physicians and health systems to improve awareness and implementation of recommended thromboprophylaxis
Interleukin-6 gene (IL-6): a possible role in brain morphology in the healthy adult brain
Background: Cytokines such as interleukin 6 (IL-6) have been implicated in dual functions in neuropsychiatric disorders. Little is known about the genetic predisposition to neurodegenerative and neuroproliferative properties of cytokine genes. In this study the potential dual role of several IL-6 polymorphisms in brain morphology is investigated. Methodology: In a large sample of healthy individuals (N = 303), associations between genetic variants of IL-6 (rs1800795; rs1800796, rs2069833, rs2069840) and brain volume (gray matter volume) were analyzed using voxel-based morphometry (VBM). Selection of single nucleotide polymorphisms (SNPs) followed a tagging SNP approach (e.g., Stampa algorigthm), yielding a capture 97.08% of the variation in the IL-6 gene using four tagging SNPs. Principal findings/results: In a whole-brain analysis, the polymorphism rs1800795 (−174 C/G) showed a strong main effect of genotype (43 CC vs. 150 CG vs. 100 GG; x = 24, y = −10, z = −15; F(2,286) = 8.54, puncorrected = 0.0002; pAlphaSim-corrected = 0.002; cluster size k = 577) within the right hippocampus head. Homozygous carriers of the G-allele had significantly larger hippocampus gray matter volumes compared to heterozygous subjects. None of the other investigated SNPs showed a significant association with grey matter volume in whole-brain analyses. Conclusions/significance: These findings suggest a possible neuroprotective role of the G-allele of the SNP rs1800795 on hippocampal volumes. Studies on the role of this SNP in psychiatric populations and especially in those with an affected hippocampus (e.g., by maltreatment, stress) are warranted.Bernhard T Baune, Carsten Konrad, Dominik Grotegerd, Thomas Suslow, Eva Birosova, Patricia Ohrmann, Jochen Bauer, Volker Arolt, Walter Heindel, Katharina Domschke, Sonja Schöning, Astrid V Rauch, Christina Uhlmann, Harald Kugel and Udo Dannlowsk
Performance measurement for co-occurring mental health and substance use disorders
<p>Abstract</p> <p>Background</p> <p>Co-occurring mental health and substance use disorders (COD) are the norm rather than the exception. It is therefore critical that performance measures are developed to assess the quality of care for individuals with COD irrespective of whether they seek care in mental health systems or substance abuse systems or both.</p> <p>Methods</p> <p>We convened an expert panel and asked them to rate a series of structure, process, and outcomes measures for COD using a structured evaluation tool with domains for importance, usefulness, validity, and practicality.</p> <p>Results</p> <p>We chose twelve measures that demonstrated promise for future pilot testing and refinement. The criteria that we applied to select these measures included: balance across structure, process, and outcome measures, quantitative ratings from the panelists, narrative comments from the panelists, and evidence the measure had been tested in a similar form elsewhere.</p> <p>Conclusion</p> <p>To be successful performance measures need to be developed in such a way that they align with needs of administrators and providers. Policymakers need to work with all stakeholders to establish a concrete agenda for developing, piloting and implementing performance measures that include COD. Future research could begin to consider strategies that increase our ability to use administrative coding in mental health and substance use disorder systems to efficiently capture quality relevant clinical data.</p
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