192 research outputs found

    Entropy-Preserving Coupling of Hierarchical Gas Models

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    This paper is concerned with coupling conditions at junctions for transport models which differ in their fidelity to describe transient flow in gas pipelines. It also includes the integration of compressors between two pipes with possibly different models. A hierarchy of three one-dimensional gas transport models is built through the 3x3 polytropic Euler equations, the 2x2 isentropic Euler equations and a simplified version of it for small velocities. To ensure entropy preservation, we make use of the novel entropy-preserving coupling conditions recently proposed by Lang and Mindt [Netw. Heterog. Media, 13:177-190, 2018] and require the continuity of the total enthalpy at the junction and that the specific entropy for pipes with outgoing flow equals the convex combination of all entropies that belong to pipes with incoming flow. We prove the existence and uniqueness of solutions to generalised Riemann problems at a junction in the neighbourhood of constant coupling functions and stationary states which belong to the subsonic region. This provides the basis for the well-posedness of certain Cauchy problems for initial data with sufficiently small total variation.Comment: 28 pages, 3 figures. arXiv admin note: text overlap with arXiv:1704.0403

    Tamoxifen-like metallocifens target thioredoxin system determining mitochondrial impairment leading to apoptosis in Jurkat cells

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    Tamoxifen-like metallocifens (TLMs) of the group-8 metals (Fe, Ru, and Os) show strong anti-proliferative activity on cancer cell lines resistant to apoptosis, owing to their unique redox properties. In contrast, the thioredoxin system, which is involved in cellular redox balance, is often overexpressed in cancer cells, especially in tumour types resistant to standard chemotherapies. Therefore, we investigated the effect of these three TLMs on the thioredoxin system and evaluated the input of the metallocene unit in comparison with structurally related organic tamoxifens. In vitro, all three TLMs became strong inhibitors of the cytosolic (TrxR1) and mitochondrial (TrxR2) isoforms of thioredoxin reductase after enzymatic oxidation with HRP/H2O2 while none of the organic analogues was effective. In Jurkat cells, TLMs inhibited mainly TrxR2, resulting in the accumulation of oxidized thioredoxin 2 and cell redox imbalance. Overproduction of ROS resulted in a strong decrease in the mitochondrial membrane potential, translocation of cytochrome c to the cytosol and activation of caspase 3, thus leading to apoptosis. None of these events occurred with organic tamoxifens. The mitochondrial fraction of cells exposed to TLMs contained a high amount of the corresponding metal, as quantified by ICP-OES. The lipophilic and cationic character associated with the singular redox properties of the TLMs could explain why they alter the mitochondrial function. These results provide new insights into the mechanism of action of tamoxifen-like metallocifens, underlying their prodrug behaviour and the pivotal role played by the metallocenic entity in their cytotoxic activity associated with the induction of apoptosis

    Predicting long-term disability outcomes in patients with MS treated with teriflunomide in TEMSO

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    To predict long-term disability outcomes in TEMSO core (NCT00134563) and extension (NCT00803049) studies in patients with relapsing forms of MS treated with teriflunomide. Methods: A post hoc analysis was conducted in a subgroup of patients who received teriflunomide in the core study, had MRI and clinical relapse assessments at months 12 (n = 552) and 18, and entered the extension. Patients were allocated risk scores for disability worsening (DW) after 1 year of teriflunomide treatment: 0 = low risk; 1 = intermediate risk; and 2-3 = high risk, based on the occurrence of relapses (0 to 652) and/or active (new and enlarging) T 2 -weighted (T 2 w) lesions ( 643 or >3) after the 1-year MRI. Patients in the intermediate-risk group were reclassified as responders or nonresponders (low or high risk) according to relapses and T 2 w lesions on the 18-month MRI. Long-term risk (7 years) of DW was assessed by Kaplan-Meier survival curves. Results: In patients with a score of 2-3, the risk of 12-week-confirmed DW over 7 years was significantly higher vs those with a score of 0 (hazard ratio [HR] = 1.96, p = 0.0044). Patients reclassified as high risk at month 18 (18.6%) had a significantly higher risk of DW vs those in the low-risk group (81.4%; HR = 1.92; p = 0.0004). Conclusions: Over 80% of patients receiving teriflunomide were classified as low risk (responders) and had a significantly lower risk of DW than those at increased risk (nonresponders) over 7 years of follow-up in TEMSO. Close monitoring of relapses and active T 2 w lesions after short-term teriflunomide treatment predicts a differential rate of subsequent DW long term. ClinicalTrials.gov identifier: TEMSO, NCT00134563; TEMSO extension, NCT0080304

    Tuning the High-Pressure Phase Behaviour of Highly Compressible Zeolitic Imidazolate Frameworks: From Discontinuous to Continuous Pore Closure by Linker Substitution

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    The high‐pressure behaviour of flexible zeolitic imidazolate frameworks (ZIFs) of the ZIF‐62 family with the chemical composition M(im)(2−x )(bim)(x) is presented (M(2+)=Zn(2+), Co(2+); im(−)=imidazolate; bim(−)=benzimidazolate, 0.02≀x≀0.37). High‐pressure powder X‐ray diffraction shows that the materials contract reversibly from an open pore ( op ) to a closed pore ( cp ) phase under a hydrostatic pressure of up to 4000 bar. Sequentially increasing the bim(−) fraction (x) reinforces the framework, leading to an increased threshold pressure for the op ‐to‐ cp phase transition, while the total volume contraction across the transition decreases. Most importantly, the typical discontinuous op ‐to‐ cp transition (first order) changes to an unusual continuous transition (second order) for x≄0.35. This allows finetuning of the void volume and the pore size of the material continuously by adjusting the pressure, thus opening new possibilities for MOFs in pressure‐switchable devices, membranes, and actuators

    Harmonizing Definitions for Progression Independent of Relapse Activity in Multiple Sclerosis: A Systematic Review

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    IMPORTANCE: Emerging evidence suggests that progression independent of relapse activity (PIRA) is a substantial contributor to long-term disability accumulation in relapsing-remitting multiple sclerosis (RRMS). To date, there is no uniform agreed-upon definition of PIRA, limiting the comparability of published studies. OBJECTIVE: To summarize the current evidence about PIRA based on a systematic review, to discuss the various terminologies used in the context of PIRA, and to propose a harmonized definition for PIRA for use in clinical practice and future trials. EVIDENCE REVIEW: A literature search was conducted using the search terms multiple sclerosis, PIRA, progression independent of relapse activity, silent progression, and progression unrelated to relapses in PubMed, Embase, Cochrane, and Web of Science, published between January 1990 and December 2022. FINDINGS: Of 119 identified single records, 48 eligible studies were analyzed. PIRA was reported to occur in roughly 5% of all patients with RRMS per annum, causing at least 50% of all disability accrual events in typical RRMS. The proportion of PIRA vs relapse-associated worsening increased with age, longer disease duration, and, despite lower absolute event numbers, potent suppression of relapses by highly effective disease-modifying therapy. However, different studies used various definitions of PIRA, rendering the comparability of studies difficult. CONCLUSION AND RELEVANCE: PIRA is the most frequent manifestation of disability accumulation across the full spectrum of traditional MS phenotypes, including clinically isolated syndrome and early RRMS. The harmonized definition suggested here may improve the comparability of results in current and future cohorts and data sets

    Predicting long-term disability outcomes in patients with MS treated with teriflunomide in TEMSO

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    To predict long-term disability outcomes in TEMSO core (NCT00134563) and extension (NCT00803049) studies in patients with relapsing forms of MS treated with teriflunomide. Methods: A post hoc analysis was conducted in a subgroup of patients who received teriflunomide in the core study, had MRI and clinical relapse assessments at months 12 (n = 552) and 18, and entered the extension. Patients were allocated risk scores for disability worsening (DW) after 1 year of teriflunomide treatment: 0 = low risk; 1 = intermediate risk; and 2-3 = high risk, based on the occurrence of relapses (0 to ù„2) and/or active (new and enlarging) T 2 -weighted (T 2 w) lesions (ù€3 or >3) after the 1-year MRI. Patients in the intermediate-risk group were reclassified as responders or nonresponders (low or high risk) according to relapses and T 2 w lesions on the 18-month MRI. Long-term risk (7 years) of DW was assessed by Kaplan-Meier survival curves. Results: In patients with a score of 2-3, the risk of 12-week-confirmed DW over 7 years was significantly higher vs those with a score of 0 (hazard ratio [HR] = 1.96, p = 0.0044). Patients reclassified as high risk at month 18 (18.6%) had a significantly higher risk of DW vs those in the low-risk group (81.4%; HR = 1.92; p = 0.0004). Conclusions: Over 80% of patients receiving teriflunomide were classified as low risk (responders) and had a significantly lower risk of DW than those at increased risk (nonresponders) over 7 years of follow-up in TEMSO. Close monitoring of relapses and active T 2 w lesions after short-term teriflunomide treatment predicts a differential rate of subsequent DW long term. ClinicalTrials.gov identifier: TEMSO, NCT00134563; TEMSO extension, NCT00803049

    Withdrawal of inhaled glucocorticoids and exacerbations of COPD.

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    This is the final version of the article. It first appeared from Massachusetts Medical Society via http://dx.doi.org/10.1056/NEJMoa1407154BACKGROUND: Treatment with inhaled glucocorticoids in combination with long-acting bronchodilators is recommended in patients with frequent exacerbations of severe chronic obstructive pulmonary disease (COPD). However, the benefit of inhaled glucocorticoids in addition to two long-acting bronchodilators has not been fully explored. METHODS: In this 12-month, double-blind, parallel-group study, 2485 patients with a history of exacerbation of COPD received triple therapy consisting of tiotropium (at a dose of 18 ÎŒg once daily), salmeterol (50 ÎŒg twice daily), and the inhaled glucocorticoid fluticasone propionate (500 ÎŒg twice daily) during a 6-week run-in period. Patients were then randomly assigned to continued triple therapy or withdrawal of fluticasone in three steps over a 12-week period. The primary end point was the time to the first moderate or severe COPD exacerbation. Spirometric findings, health status, and dyspnea were also monitored. RESULTS: As compared with continued glucocorticoid use, glucocorticoid withdrawal met the prespecified noninferiority criterion of 1.20 for the upper limit of the 95% confidence interval (CI) with respect to the first moderate or severe COPD exacerbation (hazard ratio, 1.06; 95% CI, 0.94 to 1.19). At week 18, when glucocorticoid withdrawal was complete, the adjusted mean reduction from baseline in the trough forced expiratory volume in 1 second was 38 ml greater in the glucocorticoid-withdrawal group than in the glucocorticoid-continuation group (P<0.001); a similar between-group difference (43 ml) was seen at week 52 (P=0.001). No change in dyspnea and minor changes in health status occurred in the glucocorticoid-withdrawal group. CONCLUSIONS: In patients with severe COPD receiving tiotropium plus salmeterol, the risk of moderate or severe exacerbations was similar among those who discontinued inhaled glucocorticoids and those who continued glucocorticoid therapy. However, there was a greater decrease in lung function during the final step of glucocorticoid withdrawal. (Funded by Boehringer Ingelheim Pharma; WISDOM ClinicalTrials.gov number, NCT00975195.).Supported by Boehringer Ingelheim Pharma

    Relations entre la croissance et l'activitĂ© en open-field chez la Poule I. – Effet de la sĂ©lection pour l'activitĂ© en open-field sur la croissance en poids et la conformation

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    Ecosystem-based approaches to reduce social vulnerability are a promising option for sustainable and efficient adaptation to climate change. Ecosystem based Adaptation (EbA) is part of overall adaptation, and takes into account multiple social, economic and cultural co-benefits for local communities. EbA encompasses adaptation policies and measures that take into account the role of ecosystem services in reducing societal vulnerability, through multi-sectoral and multi-level approaches.UCR::VicerrectorĂ­a de Docencia::Ciencias Sociales::Facultad de Ciencias Sociales::Escuela de GeografĂ­
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