156 research outputs found

    Particle Approximation of the BGK Equation

    Get PDF
    In this paper we prove the convergence of a suitable particle system towards the BGK model. More precisely, we consider an interacting stochastic particle system in which each particle can instantaneously thermalize locally. We show that, under a suitable scaling limit, propagation of chaos does hold and the one-particle distribution function converges to the solution of the BGK equation

    Non-mean-field Vicsek-type models for collective behavior

    Get PDF
    We consider interacting particle dynamics with Vicsek-type interactions, and their macroscopic Partial Differential Equation (PDE) limit, in the non-mean-field regime; that is, we consider the case in which each particle/agent in the system interacts only with a prescribed subset of the particles in the system (for example, those within a certain distance). In this non-mean-field regime the influence between agents (i.e. the interaction term) can be normalized either by the total number of agents in the system (global scaling) or by the number of agents with which the particle is effectively interacting (local scaling). We compare the behavior of the globally scaled and the locally scaled systems in many respects, considering for each scaling both the PDE and the corresponding particle model. In particular, we observe that both the locally and globally scaled particle system exhibit pattern formation (i.e. formation of traveling-wave-like solutions) within certain parameter regimes, and generally display similar dynamics. The same is not true of the corresponding PDE models. Indeed, while both PDE models have multiple stationary states, for the globally scaled PDE such (space-homogeneous) equilibria are unstable for certain parameter regimes, with the instability leading to traveling wave solutions, while they are always stable for the locally scaled one, which never produces traveling waves. This observation is based on a careful numerical study of the model, supported by further analysis

    Effects of first and second trimester vaginal bleeding on pregnancy outcome

    Get PDF
    The effects of vaginal bleeding during first and second trimester on pregnancy outcomes was assessed in a hospital-based population of 268 non-diabetic women. The group of non-bleeders comprised 173 females whereas, there were 71 females with first and 24 with second trimester bleeding. Fetal loss (abortion) occurred in 34% of first trimester and 25% of second trimester bleeders. Low birth weight and preterm delivery were significantly associated with second trimester haemorrhage. The results suggest that first and second trimester vaginal bleeding correlates with adverse infant outcomes

    Human Papillomavirus and Male Infertility: What Do We Know?

    Get PDF
    : In recent years, increasing attention has been paid to understanding the causes of infertility, which is being recognized as a growing health problem affecting large numbers of couples worldwide. Male infertility is a contributing factor in approximately 30-40% of cases, and one of its etiological causes is sexually transmitted infections (STIs). Among sexually transmitted pathogens, human papillomavirus (HPV) can contribute in various ways to the failure of spontaneous and assisted reproduction, acting in the different phases of conception, especially in the early ones. In particular, HPV infection can affect sperm DNA integrity, sperm motility, count, viability, and morphology and can induce the production of anti-sperm antibodies (ASAs). In this narrative review, we aimed to provide an overview of existing research on the potential adverse effects of HPV infection on male reproductive health. Furthermore, we analyzed how limiting the spread of the infection, particularly with gender-neutral vaccination, could be a possible therapeutic tool to counteract male and female fertility problems

    Behçet's disease: New insight into the relationship between procoagulant state, endothelial activation/damage and disease activity

    Get PDF
    Background: Behçet disease (BD) is associated with a prothrombotic state of unknown origin that may lead to life-threatening events. Calibrated Automated Thrombogram (CAT) and Rotational Thromboelastometry (ROTEM) are two global haemostasis assays that may reveal new insights into the physiopathological mechanisms of the disease and its procoagulant condition. Methods. 23 BD patients who had no signs or symptoms of current thrombosis and 33 age- and sex-matched controls were included in the study. We performed ROTEM and CAT tests and assessed erythrocyte count, platelet count, platelet contribution to clot formation and plasma levels of tissue-type plasminogen activator, plasminogen activator inhibitor type 1 (PAI-1), fibrinogen, C-reactive protein (CRP), thrombin-antithrombin III complex (TAT), D-dimer and E-selectin (ES). Results: Both ROTEM and CAT tests showed a hypercoagulable state in the BD patients. Plasma levels of PAI-1, fibrinogen, TAT, CRP and ES were significantly increased in this group compared to controls. The disease activity (DA) was significantly correlated with levels of ES and the maximum clot firmness, and this last one, in turn, correlated with rising levels of ES, PAI-1, CRP and fibrinogen. CAT parameters did not correlate with DA or ES. Conclusions: Both ROTEM and CAT tests reveal that patients with BD have a procoagulant state even in the absence of thrombosis. ROTEM test indicates that increased levels of fibrinogen and PAI-1 may be involved in the prothrombotic state of this pathology, while platelets do not significantly contribute. Moreover, CAT assay demonstrate that plasma from BD patients is able to generate more thrombin than controls in response to the same stimulus and that this effect is independent of the DA and the endothelial impairment suggesting the involvement of another factor in the hypercoagulable state observed in BD patients. This study also shows that endothelium activation/damage may be a contributing factor in both the procoagulant and clinical conditions of BD, as shown by the direct correlation between ES levels, ROTEM parameters and DAThis work was supported by grants from FIS PS09/00531 and FIS PI12/0183

    Impaired circadian heart rate variability in Parkinson's disease: A time-domain analysis in ambulatory setting

    Get PDF
    Background: Heart rate variability (HRV) decreases in Parkinson's disease (PD) and it can be considered a marker for cardiovascular dysautonomia. The purpose of this pilot study is to evaluate long-term time-domain analysis of HRV of PD patients and compare the results with those of matched healthy individuals. Methods: Idiopathic PD patients without comorbidity impairing HRV, and age-matched healthy individuals were recruited in a pilot study. A long-term time domain analysis of HRV using 24-h ambulatory ECG was performed. Results: Overall, 18 PD patients fulfilling inclusion criteria completed the evaluation (mean age was 55.6 ± 8.8, disease duration: 5.0 ± 4.7). Mean SCOPA-AUT score was 10.1 ± 7.3. Patients were on Hoehn & Yahr stage 1-2 and mean Levodopa Equivalent Dose (LED) was 311 ± 239.9. Mean of the 5-min standard deviation (SD) of R-R intervals distribution (SDNN) for all 5 min segments of the entire recording (ISDNN) was significantly lower in patients compared to controls. ISDNN was significantly different between Parkinson's disease patients and healthy controls. Conclusions: In our population characterized by mild to moderate disease severity, time-domain assessment of HRV seemed to be a potential tool to characterize cardiovascular dysautonomia. Decrease of ISDNN in PD may reflect an autonomic derangement extending all day and night long

    Daya Tahan Spermatozoa Dalam Semen Cair Babi Landrace Pada Metode Penyimpanan Berbeda

    Full text link
    Tujuan dilaksanakan penelitian ini untuk melihat pengaruh metode penyimpanan preservasi yang berbeda terhadap viabilitas spermatozoa semen babi landrace dalam pengencer alami air buah lontar (AL) dengan penambahan kuning telur ayam kampung (KT).  Semen diambil dari 5 ekor pejantan landrace yang telah dewasa kelamin. Setelah itu dilakukan pemeriksaan makros-mikros dari semen segar, semen dengan kriteria  motilitas , konsentrasi dan abnormalitas spermatozoa berturt-turut: >70%, >200 juta spermatozoa/ml, <20% yang layak untuk dijadikan semen cair. Perlakuan dalam penelitian:, P1(AL 95%+5% KT), P2(AL 85%+15% KT), P3(AL 75%+25% KT) yang simpan pada metode water jacket (WJ) dan P4(AL 95%+5% KT), P5(AL 85%+15% KT), P6(AL 75%+25% KT) yang disimpan dengan metode non water jacket (NWJ),  semen dikemas dalam mikrotube 1 ml dan disimpan pada suhu preservasi. Pada penelitian ini menunjukkan bahwa viabilitas spermatozooa dalam pengencer alami air buah lontar yang ditambahkan dengan kuning telur ayam kampung memperlihatkan hasil yang baik pada kombinasi AL 85% dan KT25% pada penyimpanan water jacket.  Semen cair pada pengencer kombinasi tersebut diatas mampu bertahan hingga 28 jam penyimpanan

    Is asthma control more than just an absence of symptoms? An expert consensus statement

    Get PDF
    Purpose: Definitions and measures of asthma control used in clinical trials and in clinical practice vary considerably. There is also misalignment between patients and healthcare professionals (HCPs) in terms of understanding and managing asthma control. This study aimed to progress towards a consensus definition of asthma control, and evaluate disparities between HCP and patient perspectives. Basic procedures: A two-stage Delphi questionnaire involving asthma specialists sought to identify areas of consensus on aspects of asthma control in clinical practice. Results were compared with those of a structured literature review to assess if existing guidance and measures of asthma control used in studies correlated with practice. Eighty-two panelists took part in the Delphi questionnaire. The structured literature review included 185 manuscripts and 31 abstracts. Main findings: Panelists agreed that there was no standard definition of asthma control, confirmed by a total of 19 different composite consensus/guideline definitions and/or validated measures of control being identified across the Delphi study and literature review. Panelists agreed on the positive associations of well-controlled asthma with patient outcomes, but not on the components or thresholds of a working definition of control. Principal conclusions: A universally accepted definition and measure of asthma control that is utilized and understood by patients, HCPs, and researchers is required

    Inhibition of Y1 receptor signaling improves islet transplant outcome

    Get PDF
    Failure to secrete sufficient quantities of insulin is a pathological feature of type-1 and type-2 diabetes, and also reduces the success of islet cell transplantation. Here we demonstrate that Y1 receptor signaling inhibits insulin release in β-cells, and show that this can be pharmacologically exploited to boost insulin secretion. Transplanting islets with Y1 receptor deficiency accelerates the normalization of hyperglycemia in chemically induced diabetic recipient mice, which can also be achieved by short-term pharmacological blockade of Y1 receptors in transplanted mouse and human islets. Furthermore, treatment of non-obese diabetic mice with a Y1 receptor antagonist delays the onset of diabetes. Mechanistically, Y1 receptor signaling inhibits the production of cAMP in islets, which via CREB mediated pathways results in the down-regulation of several key enzymes in glycolysis and ATP production. Thus, manipulating Y1 receptor signaling in β-cells offers a unique therapeutic opportunity for correcting insulin deficiency as it occurs in the pathological state of type-1 diabetes as well as during islet transplantation.Islet transplantation is considered one of the potential treatments for T1DM but limited islet survival and their impaired function pose limitations to this approach. Here Loh et al. show that the Y1 receptor is expressed in β- cells and inhibition of its signalling, both genetic and pharmacological, improves mouse and human islet function.info:eu-repo/semantics/publishe
    corecore