288 research outputs found

    Local Investors’ Preferences and Capital Structure

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    We provide evidence that publicly listed firms respond to capital supply conditions shaped by local investing preferences. The local supply of credit is higher and more stable in areas where demographics suggest that local investors prefer safer portfolios. We find that firms headquartered in these areas use more debt financing. The demographics-leverage relation is more pronounced for non-investment-grade and unrated firms that cannot easily tap public markets (about two-thirds of U.S. public companies). Analyses of firms’ financing activities around exogenous shocks to credit supplies – including interstate banking deregulation and the 2008-2009 financial crisis – support the capital supply effect. As demographics change slowly, local investors’ preferences may contribute to the heterogeneity and persistence of public firms’ capital structures

    Development of minimal fermentation media supplementation for ethanol production using two Saccharomyces cerevisiae strains

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    Ethanol production by fermentation is strongly dependent on media composition. Specific nutrients, such as trace elements, vitamins and nitrogen will affect the physiological state and, consequently, the fermentation performance of the micro-organism employed. The purpose of this study has been to assess the highest ethanol production by a minimal medium, instead of the more complex nutrients supplementation used during alcoholic fermentation. All fermentation tests were carried out using a microwell plate reader to monitor the processes. Two Saccharomyces cerevisiae strains (NCYC 2826 and NCYC 3445) were tested using three nitrogen sources, supplied with different vitamin and salts. The results show that solutions made of urea phosphate, KCl, MgSO4·7H2O, Ca-panthothenate, biotin allowed an ethanol yield of 22.9 and 23.4 g/L for strain NCYC 2826 and NCYC 3445, respectively, representing 90 and 92% of the theoretical yield. All tests were carried out using glucose as common reference carbon source

    A Conserved Mechanism for Sulfonucleotide Reduction

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    Sulfonucleotide reductases are a diverse family of enzymes that catalyze the first committed step of reductive sulfur assimilation. In this reaction, activated sulfate in the context of adenosine-5′-phosphosulfate (APS) or 3′-phosphoadenosine 5′-phosphosulfate (PAPS) is converted to sulfite with reducing equivalents from thioredoxin. The sulfite generated in this reaction is utilized in bacteria and plants for the eventual production of essential biomolecules such as cysteine and coenzyme A. Humans do not possess a homologous metabolic pathway, and thus, these enzymes represent attractive targets for therapeutic intervention. Here we studied the mechanism of sulfonucleotide reduction by APS reductase from the human pathogen Mycobacterium tuberculosis, using a combination of mass spectrometry and biochemical approaches. The results support the hypothesis of a two-step mechanism in which the sulfonucleotide first undergoes rapid nucleophilic attack to form an enzyme-thiosulfonate (E-Cys-S-SO(3) (−)) intermediate. Sulfite is then released in a thioredoxin-dependent manner. Other sulfonucleotide reductases from structurally divergent subclasses appear to use the same mechanism, suggesting that this family of enzymes has evolved from a common ancestor

    Does bariatric surgery improve cardiac autonomic modulation assessed by heart rate variability? A systematic review

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    Objectives. Our study aimed to explore the influence of Bariatric Surgery (BS) on heart rate (HR) variability (HRV) through a systematic review. Data Sources. Manuscripts were selected based on electronic searches of MEDLINE, EMBASE and CINAHL databases from the inception of each database up to year 2020 and followed the PRISMA protocol. Searching of these studies was systematized using the PICOS strategy. Eligibility Criteria for Selecting Studies. We selected randomized and non-randomized controlled trials and cohorts’ prospective studies that reported the influence of BS on HRV. We assessed the quality rating using the Black and Downs questionnaire. Results. Following the screening and eligibility stages, 14 studies were included in the review. All studies agreed that BS promotes an increase in parasympathetic HR control and HRV and, a decrease in HR. Yet, the literature does not provide evidence that this outcome was directly caused by the surgical procedure. There is limited evidence to support that patients with type 2 Diabetes Mellitus (TDM2) have greater improvement in HRV as an interim measure, to individuals without. The decrease in insulin resistance was correlated with the increase in HRV in some studies, but, other studies are unsupportive of this outcome. Improvements in two metabolic parameters (e.g., Leptin, NT-proBNP) were connected with a superior increase in HRV

    Mycobacterium tuberculosis causing tuberculous lymphadenitis in Maputo, Mozambique

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    BACKGROUND: The zoonosis bovine tuberculosis (TB) is known to be responsible for a considerable proportion of extrapulmonary TB. In Mozambique, bovine TB is a recognised problem in cattle, but little has been done to evaluate how Mycobacterium bovis has contributed to human TB. We here explore the public health risk for bovine TB in Maputo, by characterizing the isolates from tuberculous lymphadenitis (TBLN) cases, a common manifestation of bovine TB in humans, in the Pathology Service of Maputo Central Hospital, in Mozambique, during one year. RESULTS: Among 110 patients suspected of having TBLN, 49 had a positive culture result. Of those, 48 (98 %) were positive for Mycobacterium tuberculosis complex and one for nontuberculous mycobacteria. Of the 45 isolates analysed by spoligotyping and Mycobacterial Interspersed Repetitive Unit - Variable Number Tandem Repeat (MIRU-VNTR), all were M. tuberculosis. No M. bovis was found. Cervical TBLN, corresponding to 39 (86.7 %) cases, was the main cause of TBLN and 66.7 % of those where from HIV positive patients. We found that TBLN in Maputo was caused by a variety of M. tuberculosis strains. The most prevalent lineage was the EAI (n?=?19; 43.2 %). Particular common spoligotypes were SIT 48 (EAI1_SOM sublineage), SIT 42 (LAM 9), SIT 1 (Beijing) and SIT53 (T1), similar to findings among pulmonary cases. CONCLUSIONS: M. tuberculosis was the main etiological agent of TBLN in Maputo. M. tuberculosis genotypes were similar to the ones causing pulmonary TB, suggesting that in Maputo, cases of TBLN arise from the same source as pulmonary TB, rather than from an external zoonotic source. Further research is needed on other forms of extrapulmonary TB and in rural areas where there is high prevalence of bovine TB in cattle, to evaluate the risk of transmission of M. bovis from cattle to humans.Swedish International Development Cooperation Agency / Department for Research Cooperation (Sida/SAREC) through Eduardo Mondlane University and Karolinska Institutet Research and Training (KIRT) collaboratio

    Expression of Stem Cell Markers in the Human Fetal Kidney

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    In the human fetal kidney (HFK) self-renewing stem cells residing in the metanephric mesenchyme (MM)/blastema are induced to form all cell types of the nephron till 34th week of gestation. Definition of useful markers is crucial for the identification of HFK stem cells. Because wilms' tumor, a pediatric renal cancer, initiates from retention of renal stem cells, we hypothesized that surface antigens previously up-regulated in microarrays of both HFK and blastema-enriched stem-like wilms' tumor xenografts (NCAM, ACVRIIB, DLK1/PREF, GPR39, FZD7, FZD2, NTRK2) are likely to be relevant markers. Comprehensive profiling of these putative and of additional stem cell markers (CD34, CD133, c-Kit, CD90, CD105, CD24) in mid-gestation HFK was performed using immunostaining and FACS in conjunction with EpCAM, an epithelial surface marker that is absent from the MM and increases along nephron differentiation and hence can be separated into negative, dim or bright fractions. No marker was specifically localized to the MM. Nevertheless, FZD7 and NTRK2 were preferentially localized to the MM and emerging tubules (<10% of HFK cells) and were mostly present within the EpCAMneg and EpCAMdim fractions, indicating putative stem/progenitor markers. In contrast, single markers such as CD24 and CD133 as well as double-positive CD24+CD133+ cells comprise >50% of HFK cells and predominantly co-express EpCAMbright, indicating they are mostly markers of differentiation. Furthermore, localization of NCAM exclusively in the MM and in its nephron progenitor derivatives but also in stroma and the expression pattern of significantly elevated renal stem/progenitor genes Six2, Wt1, Cited1, and Sall1 in NCAM+EpCAM- and to a lesser extent in NCAM+EpCAM+ fractions confirmed regional identity of cells and assisted us in pinpointing the presence of subpopulations that are putative MM-derived progenitor cells (NCAM+EpCAM+FZD7+), MM stem cells (NCAM+EpCAM-FZD7+) or both (NCAM+FZD7+). These results and concepts provide a framework for developing cell selection strategies for human renal cell-based therapies

    Recruiting Care Homes to a Randomised Controlled Trial

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    Background There are over a quarter of a million individuals aged ≥65 years resident in care homes in England and Wales. Care home residents have high levels of cognitive impairment, physical disability, multimorbidity and polypharmacy. Research is needed to ensure there are robust, evidence-based interventions to improve the quality of life of this frail group. However, there is a paucity of research studies in this area. Recruiting care homes and their residents to research is challenging. A feasibility, cluster randomised controlled trial was undertaken as part of a research programme to identify ways to develop and test methods to enhance the physical activity of care home residents. This paper describes two methods of recruiting care homes to the trial and draws out learning to inform future studies. Methods Eligible care homes: were within a defined geographical area in the north of England; provided residential care for adults ≥65 years of age; had not previously been involved in the research programme; were not taking part in a conflicting study; were not recorded on the Care Quality Commission website as ‘inadequate’ or ‘requiring improvements’ in any area; had ≥10 beds. Care homes were identified by: a ‘systematic approach’ using the Care Quality Commission website database of care homes; a ‘targeted approach’ via a network of research-ready care homes. A standardised method was used to recruit care homes including: eligibility screening; invitation letters; telephone contact; visits; formal letter of agreement. Results In the systematic approach, 377 care homes were screened, 230 (61%) were initially eligible and invited to participate, 11 were recruited (recruitment rate (RR) 4.8%). In the targeted approach, 15 care homes were invited to participate, two were recruited (RR 13.3%). Overall, 245 care homes were approached and 13 recruited (RR 5.3%). A variety of care homes were recruited to the trial in terms of size, location, ownership and care provision. Conclusions Systematic recruitment of care homes to the study was time-consuming and resource-heavy but led to a variety of care homes being recruited. The targeted approach led to a higher recruitment rate. Trial registration ISRCTN registry, ISRCTN16076575. Registered 25 June 2015, http://www.isrctn.com/ISRCTN1607657
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