788 research outputs found

    Immunologic Regulation in Pregnancy: From Mechanism to Therapeutic Strategy for Immunomodulation

    Get PDF
    The immunologic interaction between the fetus and the mother is a paradoxical communication that is regulated by fetal antigen presentation and/or by recognition of and reaction to these antigens by the maternal immune system. There have been significant advances in understanding of abnormalities in the maternal-fetal immunologic relationship in the placental bed that can lead to pregnancy disorders. Moreover, immunologic recognition of pregnancy is vital for the maintenance of gestation, and inadequate recognition of fetal antigens may cause abortion. In this paper, we illustrate the complex immunologic aspects of human reproduction in terms of the role of human leukocyte antigen (HLA), immune cells, cytokines and chemokines, and the balance of immunity in pregnancy. In addition, we review the immunologic processes of human reproduction and the current immunologic therapeutic strategies for pathological disorders of pregnancy

    Analyzing experiences of using effective feedback in the ESL classroom through the use of digital technologies

    Get PDF
    This article of systematic literature review presents the analysis of a series of experiences that use effective feedback in educational activities through the use and integration of digital technologies, specifically, in the classes of English as a second language in higher education. The revision analyzed 14 different experiences. As part of the analysis, criteria are defined to describe and compare them, linked with the possibilities of feedback to favor the formative processes at the higher education level. Criteria include: country of origin and level of education, design of feedback used, the timing of the feedback, the means of providing feedback, and the consideration of digital technologies. The main results indicate that the use of feedback, in the ESL classroom, allows learners to boost their capacity of analysis, critical thinking, and the resolution of problems linked with interlanguage. As a conclusion, the salience and positive impact of digital technologies are highlighted in favoring the positive and effective feedback, in the particular case of English as a second language. Finally, it is evident the use of computer -mediation, screencast, and web-based learning environments as the primary sources of authors used more frequently to implement effective feedback in higher education. It concludes that the set of experiences analyzed provides light in terms of the considerations needed to design and adjust formative processes that allow boosting effective feedback mediated by digital technologies. As future work, there will be the elaboration of a methodological proposal that helps to adjust the formative processes that enable the integration of digital technologies as mediators in the process of feedback between teachers and learners.UCR::Sedes Regionales::Sede del Atlántico::Recinto de GuápilesUCR::Sedes Regionales::Sede del Carib

    Electronic band structures of Ge1−xSnx semiconductors: A first-principles density functional theory study

    Get PDF
    [[abstract]]We conduct first-principles total-energy density functional calculations to study the band structures in Ge 1− x Sn x infrared semiconductor alloys. The norm-conserving optimized pseudopotentials of Ge and Sn have been constructed for electronic structure calculations. The composition-bandgap relationships in Ge 1−x Sn x lattices are evaluated by a detailed comparison of structural models and their electronic band structures. The critical Sn composition related to the transition from indirect- to direct-gap in Ge 1−x Sn x alloys is estimated to be as low as x∼ 0.016 determined from the parametric fit. Our results show that the crossover Sn concentration occurs at a lower critical Sn concentration than the values predicted from the absorption measurements. However, early results indicate that the reliability of the critical Sn concentration from such measurements is hard to establish, since the indirect gap absorption is much weaker than the direct gap absorption. We find that the direct band gap decreases exponentially with the Sn composition over the range 0 0.375, in very good agreement with the theoretical observed behavior [D. W. Jenkins and J. D. Dow, Phys. Rev. B 36, 7994, 1987]. For homonuclear and heteronuclear complexes of Ge 1−x Sn x alloys, the indirect band gap at L-pointis is found to decrease homonuclear Ge-Ge bonds or increase homonuclear Sn-Sn bonds as a result of the reduced L valley. All findings agree with previously reported experimental and theoretical results. The analysis suggests that the top of valence band exhibits the localization of bond charge and the bottom of the conduction band is composed of the Ge 4s4p and/or Sn 5s5p atomic orbits.[[booktype]]紙本[[booktype]]電子

    The design of a prospective, randomized, open-labeled study to compare the efficacy of lercanidipine with amlodipine on renal function in hypertensive patients aged at least 55 years (LEADER study)

    Get PDF
    AbstractBackgroundAlthough all classes of antihypertensive treatment can successfully reduce morbidity and mortality of cardiac pathology, prevention of target organ damages is of great importance beyond blood pressure lowering. Unlike most dihydropyridines, lercanidipine dilates both afferent and the efferent arterioles of nephrons, so it may provide renoprotective effects, which other CCBs may not have. The main purpose of this study is to compare the renoprotective effect of lercanidipine and amlodipine among hypertensive people aged 55years and older with newly diagnosed hypertension or those who were treatment-naïve for one month.MethodsThe study is a prospective, open-labelled, randomized, controlled trial to enrol 232 hypertensive patients aged ≥55 years. Subjects will be randomized into lercanidipine arm (10–20mg/day) and amlodipine arm (5–10mg/day) by 1:1 ratio. The dosage can be up-titrated to 20mg/day (lercanidipine group) and 10mg/day (amlodipine group), respectively, at week 4 or any following visit thereafter. Efficacy and safety data will be collected at week 4, 12 and 24 by evaluating the blood pressure lowering, estimated glomerular filtration rate, creatinine clearance, and urine albumin-creatinine ratio.ConclusionsThe reno-protective effects of new generation of CCBs such as lercanidipine administered to patients with hypertension are not investigated well. After all, this study will bring benefit to older patients who need drugs with both excellent anti-hypertensive and reno-protective efficacy. And the results will be provided for future treatment guideline of elder population in Taiwan

    Significance of Coronary Calcification for Prediction of Coronary Artery Disease and Cardiac Events Based on 64-Slice Coronary Computed Tomography Angiography

    Get PDF
    This work aims to validate the clinical significance of coronary artery calcium score (CACS) in predicting coronary artery disease(CAD) and cardiac events in 100 symptomatic patients (aged 37–87 years, mean 62.5, 81 males) that were followed up for a mean of 5 years. Our results showed that patients with CAD and cardiac events had significantly higher CACS than those without CAD and cardiac events, respectively. The corresponding data were 1450.42 ± 3471.24 versus 130 ± 188.29 (P 1000. Increased CACS (>100)was also associated with an increased frequency of multi-vessel disease. Nonetheless, 3 (20%) out of 15 patients with zero CACS had single-vessel disease. Significant correlation (P < 0.001) was observed between CACS and CAD on a vessel-based analysis for coronary arteries. It is concluded that CACS is significantly correlated with CAD and cardiac events
    corecore