1,272 research outputs found

    Performance based earthquake assessment of an industrial silos structure and retrofit with sliding isolators

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    Recent seismic events pointed out the high vulnerability of existing industrial facilities, stressing on safety and high losses inherent to interruption of economic activities and release of environmentally hazardous materials. These structures often have irregular geometry and structural configuration, are subject to aging and corrosion, and are designed without specific performance-based or seismic design criteria. Due to these inherent complexities, retrofit using friction isolators can be a viable and practical solution for performance improvements. This work presents a case study of irregular industrial storage plant structure consisting of a group of six elevated silos resting on a steel frame on one side and connected to a vaulted RC structure on the other. A computational model is built incorporating nonlinearities from the components (braces, beams, columns, etc.) and from the mitigation devices. Retrofit using friction isolators is analyzed and evaluated through linear and nonlinear dynamic analyses under a set of natural ground motions. Results show the effectiveness of the mitigation strategy in terms of performance improvement

    Endothelial dysfunction in postmenopausal women and hypertension

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    ‘Menopause is a cardiovascular risk factor for endothelial dysfunction … It also represents a unique opportunity to study the effect of endothelial dysfunction in healthy women and predicts the development of atherosclerosis and atherosclerosis-related diseas

    Gender differences in diagnostic procedures

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    This review examines the contribution of the literature to the controversial issue of diagnostic procedures in women affected by coronary artery disease (CAD), on which a large number of papers have been published. It has been reported that cerebro- and cardiovascular diseases represent the first cause of death in the New as well as in the Old World, Italy included. Some studies are conditioned by bias; one of these is the Framingham study, in which angina was reported and defined only clinically and for a relatively young age range, as a benign condition in women. Angiographic studies, such as the CASS, considered a super elected group of women referred to the hemodynamic laboratory for chest pain, which in the female gender often has atypical characteristics. In our opinion, it is mandatory to take into account: 1) what chest pain really means in women; 2) the fact that there are gender differences: women have a different biological and hormonal status, lifestyle, and perception of the disease; 3) that there is a different approach of the physicians to a woman with possible or suspected CAD. We suggest, therefore, a more peculiar and individualized diagnostic approach to women suspected as having CAD. This approach should also take the pre-test probability of disease into consideration. The first investigational step we recommend is the exercise ECG test; should this be unfeasible or not interpretable, an imaging and/or pharmacological stress test is advisable. In case of positive first test results, coronary angiography should be performed. © 2003 CEPI Srl

    Reactive oxygen species generated in chloroplasts contribute to tobacco leaf infection by the necrotrophic fungus Botrytis cinerea

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    Reactive oxygen species (ROS) play fundamental roles in plant responses to pathogen infection, including modulation of cell death processes and defense-related gene expression. Cell death triggered as part of the hypersensitive response enhances resistance to biotrophic pathogens, but favors the virulence of necrotrophs. Even though the involvement of ROS in the orchestration of defense responses is well established, the relative contribution of specific subcellular ROS sources to plant resistance against microorganisms with different pathogenesis strategies is not completely known. The aim of this work was to investigate the role of chloroplastic ROS in plant defense against a typical necrotrophic fungus, Botrytis cinerea. For this purpose, we used transgenic Nicotiana tabacum (tobacco) lines expressing a plastid-targeted cyanobacterial flavodoxin (pfld lines), which accumulate lower chloroplastic ROS in response to different stresses. Tissue damage and fungal growth were significantly reduced in infected leaves of pfld plants, as compared with infected wild-type (WT) counterparts. ROS build-up triggered by Botrytis infection and associated with chloroplasts was significantly decreased (70–80%) in pfld leaves relative to the wild type. Phytoalexin accumulation and expression of pathogenesis-related genes were induced to a lower degree in pfld plants than in WT siblings. The impact of fungal infection on photosynthetic activity was also lower in pfld leaves. The results indicate that chloroplast-generated ROS play a major role in lesion development during Botrytis infection. This work demonstrates that the modulation of chloroplastic ROS levels by the expression of a heterologous antioxidant protein can provide a significant degree of protection against a canonical necrotrophic fungus.Fil: Rossi, Franco Rubén. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas ; ArgentinaFil: Krapp, Adriana del Rosario. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Biología Molecular y Celular de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario; ArgentinaFil: Bisaro, Fabiana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Biología Molecular y Celular de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario; Argentina. The Queens University of Belfast; IrlandaFil: Maiale, Santiago Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas ; ArgentinaFil: Pieckenstain, Fernando Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas ; ArgentinaFil: Carrillo, Nestor Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Biología Molecular y Celular de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario; Argentin

    Impegno cardiaco nella sclerosi sistemica

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    L'impegno cardiaco in corso di sclerosi sistemia consta di uno spettro variabile di manifestazioni cliniche conseguenti ad alterazioni di natura microangiopatica, elettrica e/o emodinamica. In danno ischemico e/o flogistico autoimmune del miocardio producono, in ultima analisi, il quadro istopatologico caratteristico della 'necrosi a bande' con deposizione di tessuto fibroso, responsabile della riduzione di elasticità e della capacità contrattile muscolare. ...

    Importance of the time of initiation of mineralocorticoid receptor antagonists on risk of mortality in patients with heart failure

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    Introduction: Several studies have definitively shown the benefit of mineralocorticoid receptor antagonists (MRAs) in patients with heart failure (HF). However, very few prior studies examined the relationship between the timing of initiation of MRAs and prognosis. In addition, on this topic, there is no information regarding the specific population of patients suffering a first episode of decompensated congestive HF. Methods: We studied a homogenous cohort of patients discharged alive from our hospital after a first episode of decompensated congestive HF, in order to clarify the association between time of aldosterone receptor antagonist (ARA) initiation (within the first 90 days after hospital discharge) and mortality. Our population was composed of a series of consecutive patients. All-cause mortality was compared between patients who initiated MRAs at discharge (early group) and those who initiated MRAs one month later and up to 90 days after discharge (delayed group). We used prescription time distribution matching to control for survival difference between groups. Results: The early and delayed groups consisted of 365 and 320 patients, respectively. During the one-year follow-up, a significant difference in mortality was demonstrated between groups. Adjusted hazard ratios (HRs) for early versus delayed initiation were 1.72 (95% confidence interval (CI) 0.96 to 2.84) at six months, and 1.93 (95% CI 1.18 to 3.14) at one year. Conclusions: Delay of MRA initiation up to 30 to 90 days after discharge implies a significant increase in mortality compared with MRA initiation at discharge, after a first episode of decompensate congestive HF

    The involvement of T regulatory lymphocytes in a cohort of lupus nephritis patients: a pilot study

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    T regulator lymphocytes (Tregs) play a key role in the maintenance of immune tolerance and in the development of autoimmune diseases. Expression of Foxp3 is specific for Tregs, and can be used for the identification of these cells. This study investigated the variations of Tregs Foxp3? in the kidney biopsies inflammatory infiltrate of different lupus nephritis classes compared to that of ANCA glomerulonephritis, acute tubulointerstitial nephritis and nephroangiosclerosis. Sections of paraffin-embedded tissue have been stained by immunohistochemistry with anti-CD3 and anti-FoxP3 antibodies. We find that the ratio of FoxP3?/CD3? cells is significantly lower in patients with lupus nephritis class IV and in patients with vasculitides than in the course of nephroangiosclerosis, tubulointerstitial nephritis and lupus nephritis class V. The data presented herein demonstrate a decrease of FoxP3? Treg cells in the inflammatory infiltrate of lupus nephritis, particularly during the most active phases of lupus nephritis, as observed in the course of a IV class nephritis

    The Isolation and Identification of Bacteria on Feathers of Migratory Bird Species

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    Worldwide, bacteria are the most ubiquitous microorganisms, and it has been extensively demonstrated that migratory wild birds can increase bacterial global scale dispersion through long-distance migration and dispersal. The microbial community hosted by wild birds can be highly diverse, including pathogenic strains that can contribute to infections and disease spread. This study focused on feather and plumage bacteria within bird microbial communities. Samples were collected during ornithological activities in a bird ringing station. Bacterial identification was carried out via DNA barcoding of the partial 16S rRNA gene. Thirty-seven isolates of bacteria were identified on the chest feathers of 60 migratory birds belonging to three trans-Saharan species: Muscicapa striata, Hippolais icterina, and Sylvia borin. Our results demonstrate the possibility of bacterial transfer, including pathogens, through bird migration between very distant countries. The data from the analysis of plumage bacteria can aid in the explanation of phenomena such as migratory birds’ fitness or the development of secondary sexual traits. Moreover, these results have deep hygienic–sanitary implications, since many bird species have synanthropic behaviors during their migration that increase the probability of disease sprea

    Vibration signature analysis for rotor broken bar diagnosis in double cage induction motor drives

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    The paper investigates the diagnosis of rotor broken bars in field oriented controlled (FOC) double cage induction motor drives, using current and vibration signature analysis techniques. The Impact of the closed loop control system cannot be neglected when the detection of asymmetries in the machine are based on the signature analysis of electrical variables. The proposed diagnosis approach is based on optimized use of wavelet analysis by a pre-processing of phase current or axial/radial vibration signals. Thus, the time evolution of the tracked rotor fault components can be effectively analyzed. This paper shows also the relevance of the fault components computed from axial vibration signal in comparison to those coming from phase current and radial vibration signals. Cyclic fault quantification, issued from the wavelet analysis, has been introduced for accurate rotor fault detection. Experimental results show the validity of the proposed technique, leading to an effective diagnosis procedure for rotor broken bar in double cage induction motor

    Diagnosis of mechanical unbalance for double cage induction motor load in time-varying conditions based on motor vibration signature analysis

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    This paper investigates the detectability of mechanical unbalance in double cage induction motor load using motor vibration signature analysis technique. Rotor imbalances induce specific harmonic components in electrical, electromagnetical, and mechanical quantities. Harmonic components characteristic of this category of rotor faults, issued from vibration signals analysis, are closely related to rotating speed of the rotor, which complicates its detection under non-stationary operating conditions of the motor. Firstly, experimental results were performed first under healthy and mechanical load unbalance cases, for different load levels under steady-state operating conditions to evaluate the sensitivity of motor axial vibration signature analysis (MAVSA) and motor radial vibration signature analysis (MRVSA) techniques. Secondly, and in order to overcome the limitations of the FFT analysis in time-varying conditions, a simple and effective method based on advanced use of wavelet analysis is proposed, that allows the diagnosis of mechanical load unbalance for a double cage induction machine operating under non-stationary conditions. Experimental tests were conducted for these purposes showing the effectiveness of the presented technique under time-varying operating conditions
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