203 research outputs found

    High potential for weathering and climate effects of non-vascular vegetation in the Late Ordovician

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    It has been hypothesized that predecessors of today’s bryophytes significantly increased global chemical weathering in the Late Ordovician, thus reducing atmospheric CO2 concentration and contributing to climate cooling and an interval of glaciations. Studies that try to quantify the enhancement of weathering by non-vascular vegetation, however, are usually limited to small areas and low numbers of species, which hampers extrapolating to the global scale and to past climatic conditions. Here we present a spatially explicit modelling approach to simulate global weathering by non-vascular vegetation in the Late Ordovician. We estimate a potential global weathering flux of 2.8 (km3 rock) yr−1, defined here as volume of primary minerals affected by chemical transformation. This is around three times larger than today’s global chemical weathering flux. Moreover, we find that simulated weathering is highly sensitive to atmospheric CO2 concentration. This implies a strong negative feedback between weathering by non-vascular vegetation and Ordovician climate

    Interferon ÎČ-1a in relapsing multiple sclerosis: four-year extension of the European IFNÎČ-1a Dose-C omparison Study

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    Background: Multiple sclerosis (MS) is a chronic disease requiring long-term monitoring of treatment. Objective: To assess the four-year clinical efficacy of intramuscular (IM) IFNb-1a in patients with relapsing MS from the European IFNb-1a Dose-C omparison Study. Methods: Patients who completed 36 months of treatment (Part 1) of the European IFNb-1a Dose-C omparison Study were given the option to continue double-blind treatment with IFNb-1a 30 mcg or 60 mcg IM once weekly (Part 2). Analyses of 48-month data were performed on sustained disability progression, relapses, and neutralizing antibody (NA b) formation. Results: O f 608/802 subjects who completed 36 months of treatment, 493 subjects continued treatment and 446 completed 48 months of treatment and follow-up. IFNb-1a 30 mcg and 60 mcg IM once weekly were equally effective for up to 48 months. There were no significant differences between doses over 48 months on any of the clinical endpoints, including rate of disability progression, cumulative percentage of patients who progressed (48 and 43, respectively), and annual relapse rates; relapses tended to decrease over 48 months. The incidence of patients who were positive for NAbs at any time during the study was low in both treatment groups. Conclusion: C ompared with 60-mcg IM IFNb-1a once weekly, a dose of 30 mcg IM IFNb-1a once weekly maintains the same clinical efficacy over four years

    Minimizing Incision in Living Donor Liver Transplantation: Initial Experience and Comparative Analysis of Upper Midline Incision in 115 Recipients

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    Living donor liver transplantation (LDLT) needs “Mercedes Benz” or “J-shaped” incision, causing short and long-term complications. An upper midline incision (UMI) is less invasive alternative but technically challenging. Reporting UMI for recipients in LDLT vs. conventional J-shaped incision. Retrospective analysis, July 2021 to December 2022. Peri-operative details and post-transplant outcomes of 115 consecutive adult LDLT recipients transplanted with UMI compared with 140 recipients with J-shaped incision. Cohorts had similar preoperative and intraoperative variables. The UMI group had significant shorter time to ambulation (3 ± 1.6 vs. 3.6 ± 1.3 days, p = 0.001), ICU stay (3.8 ± 1.3 vs. 4.4 ± 1.5 days, p = 0.001), but a similar hospital stay (15.6±7.6 vs. 16.1±10.9 days, p = 0.677), lower incidence of pleural effusion (11.3% vs. 27.1% p = 0.002), and post-operative ileus (1.7% vs. 9.3% p = 0.011). The rates of graft dysfunction (4.3% vs. 8.5% p = 0.412), biliary complications (6.1% vs. 12.1% p = 0.099), 90-day mortality (7.8% vs. 12.1% p = 0.598) were similar. UMI-LDLT afforded benefits such as reduced pleuropulmonary complications, better early post-operative recovery and reduction in scar-related complaints in the medium-term. This is a safe, non-inferior and reproducible technique for LDLT

    Nitric oxide synthases and tubal ectopic pregnancies induced by Chlamydia infection: basic and clinical insights

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    Human ectopic pregnancy (EP) remains a common cause of pregnancy-related first trimester death. Nitric oxide (NO) is synthesized from L-arginine by three NO synthases (NOS) in different tissues, including the Fallopian tube. Studies of knockout mouse models have improved our understanding of the function of NOS isoforms in reproduction, but their roles and specific mechanisms in infection-induced tubal dysfunction have not been fully elucidated. Here, we provide an overview of the expression, regulation and possible function of NOS isoforms in the Fallopian tube, highlighting the effects of infection-induced changes in the tubal cellular microenvironment (imbalance of NO production) on tubal dysfunction and the potential involvement of NOS isoforms in tubal EP after Chlamydia trachomatis genital infection. The non-equivalent regulation of tubal NOS isoforms during the menstrual cycle suggests that endogenous ovarian steroid hormones regulate NOS in an isoform-specific manner. The current literature suggests that infection with C. trachomatis induces an inflammatory response that eventually leads to tubal epithelial destruction and functional impairment, caused by a high NO output mediated by inducible NOS (iNOS). Therefore, tissue-specific therapeutic approaches to suppress iNOS expression may help to prevent ectopic implantation in patients with prior C. trachomatis infection of the Fallopian tube

    Linear transformations of Srivastava's HCH_C triple hypergeometric function

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    We explore the large set of linear transformations of Srivastava's HCH_C triple hypergeometric function. This function has been recently linked to the massive one-loop conformal scalar 3-point Feynman integral. We focus here on the class of linear transformations of HCH_C that can be obtained from linear transformations of the Gauss 2F1_2F_1 hypergeometric function and, as HCH_C is also a three variable generalization of the Appell F1F_1 double hypergeometric function, from the particular linear transformation of F1F_1 known as Carlson's identity and some of its generalizations. These transformations are applied at the level of the 3-fold Mellin-Barnes representation of HCH_C. This allows us to use the powerful conic hull method of Phys. Rev. Lett. 127 (2021) no.15, 151601 for the evaluation of the transformed Mellin-Barnes integrals, which leads to the desired results. The latter can then be checked numerically against the Feynman parametrization of the conformal 3-point integral. We also show how this approach can be used to derive many known (and less known) results involving Appell double hypergeometric functions
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