131 research outputs found

    Innovative Modeling of Outcome in Cardiac Surgery

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    In the normal heart both left and right ventricle have a valve at the atrio-ventricular connection and at the ventriculo-arterial connection. In the left ventricle the inflow valve is the mitral valve and the outflow valve is the aortic valve. In the right ventricle the inflow valve is the tricuspid valve and the outflow valve is the pulmonary valve. These heart valves ascertain that blood only flows in one direction through the heart. The valves are made of strong, thin flaps of tissue, called leaflets. The valves control the blood flow through the heart by opening and closing the leaflets during the contractions of the heart. Heart valve disease occurs when one or more of the heart valves do not work correctly because of valvular stenosis or valvular regurgitation, or a combination of the two. Valvular stenosis occurs when a heart valve doesn’t fully open due to stiff or fused leaflets or when a valve is congenitally too small. This limits the amount of blood that can flow through the valve. Valvular regurgitation, also known as valvular insufficiency, occurs when a valve does not close properly. This will lead to blood leaking back through the valve when it should be closed. All four heart valves can develop stenosis, regurgitation of a combination of both stenosis and regurgitation. In case heart valve disease is not treated, it can have negative impact on a person’s quality of life and may even become life-threatening. During the past decades, great advances in the surgical treatment of heart valves disease have been achieved. This thesis will focus on the surgical treatment of aortic and pulmonary valve disease

    Effect of Some Medicinal Plants as Feed Additives on Growth Performance, Blood Constituents and Carcass Characteristics of Broilers

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    The present work aimed to study the effect of feeding broiler chicks on diets containing different levels of fenugreek, anise and curcuma seeds powder, as natural feed additive on productive performance, carcass characteristics, some blood constituents and economic feed efficiency. One hundred and forty, one-day old (Ross 38) unsexed broiler chicks were obtained from local commercial source, weighed and randomly distributed to 7 equal groups, each of 20. The birds were fed with two basal diets (starter and finisher diets). The experimental diets were as follows: basal control diet without any feed additives (G1), basal diets supplemented with 0.2 and 0.5% fenugreek (G2 and G3 respectively), basal diets supplemented with 0.3 and 0.6% anise seeds (G4 and G5 respectively), and lastly basal diets supplemented with 0.3 and 0.5% curcuma (G6 and G7 respectively). During the experiment the body weight and feed intake were measured and consequently, weight gain and feed conversion ratio were calculated. At the end of the experiment, three birds from each group were slaughtered for blood sampling and serum extraction then. Finally, economical evaluation of the diets was calculated. The results showed that, dietary inclusion of fenugreek, anise and curcuma, had significant (P <0.05) improvement in the live body weight, total weight gain and feed conversion ratio, While, the feed intake was not affected by the dietary inclusion of them. Some blood constituents were affected with these additions. The relative economic feed efficiency was increased by dietary inclusion of the three additives

    Classification of Message Spreading in a Heterogeneous Social Network

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    Nowadays, social networks such as Twitter, Facebook and LinkedIn become increasingly popular. In fact, they introduced new habits, new ways of communication and they collect every day several information that have different sources. Most existing research works fo-cus on the analysis of homogeneous social networks, i.e. we have a single type of node and link in the network. However, in the real world, social networks offer several types of nodes and links. Hence, with a view to preserve as much information as possible, it is important to consider so-cial networks as heterogeneous and uncertain. The goal of our paper is to classify the social message based on its spreading in the network and the theory of belief functions. The proposed classifier interprets the spread of messages on the network, crossed paths and types of links. We tested our classifier on a real word network that we collected from Twitter, and our experiments show the performance of our belief classifier

    A study on oxidative stress biomarkers and immunomodulatory effects of pesticides in pesticide-sprayers

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    AbstractThis work was conducted on 95 adult males from Al-Salheya Algadeeda-Sharkeya governorate. They were classified according to pesticides residues into control group (30 unexposed healthy adult males living in the same area), insecticides exposed workers group (55 adult males exposed to organophosphate and carbamates) and fungicides exposed workers group (10 adult males exposed to fungicides). The study was designed to investigate and compare the oxidative stress and immunomodulatory effects of pesticides exposure among agricultural workers according the level of pesticide residues in their blood which was measured by HPLC. The oxidative stress status has been evaluated by assessment of (SH-protein), glutathione-S-transferase (GST), glutathione reductase (GR), total antioxidant capacity and malondialdehyde (MDA). In addition, the acetylcholinesterase (AchE) activity was measured as a biomarker of toxicity. We used IgG, IgM, as immunological biomarkers to test the humoral immune function as well as TNFα as a biomarker of cellular immune function. Our result revealed statistically significant reduction of the activity of (AchE), antioxidant defense enzymes, total antioxidant capacity, IgM and IgG while, MDA and TNF levels showed significant elevations in insecticides-exposed workers versus control. Results of fungicides exposed workers revealed non-significant reduction of the activity of (AchE), antioxidant defense enzymes, IgM, IgG and TNFα levels while there was significant elevation of MDA level and significant reduction of total antioxidant capacity level

    Integrated application of bacterial carbonate precipitation and silicon nanoparticles enhances productivity, physiological attributes, and antioxidant defenses of wheat (Triticum aestivum L.) under semi-arid conditions

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    The use of calcium carbonate-precipitating bacteria (CCPB) has become a well-established ground-improvement technique. However, the effect of the interaction of CCPB with nanoparticles (NPs) on plant performance is still meager. In this study, we aimed at evaluating the role of CCPB and/or silicon NPs (Si-NPs) on the growth, physio-biochemical traits, and antioxidative defense of wheat (Triticum aestivum L.) under semi-arid environmental conditions. A 2-year pot experiment was carried out to determine the improvement of the sandy soil inoculated with CCPB and the foliar application of Si-NPs on wheat plants. We tested the following treatments: spraying plants with 1.0 or 1.5 mM Si-NPs (control = 0 mM Si-NPs), soil inoculated with Bacillus lichenforms (MA16), Bacillus megaterium (MA27), or Bacillus subtilis (MA34), and the interaction of individual Bacillus species with Si-NPs. Our results showed that soil inoculation with any of the three isolated CCPB and/or foliar application of Si-NPs at the rates of 1.0 or 1.5 mM significantly improved (p ≤ 0.05) the physiological and biochemical attributes as well as the enzymatic antioxidant activities of wheat plants. Therefore, the combined treatments of CCPB + Si-NPs were more effective in enhancing physio-biochemical characteristics and enzymatic antioxidant activities than the individual treatments of CCPB or Si-NPs, thus achieving the best performance in the treatment of MA34 + 1.5 mM Si-NPs. Our results demonstrated that the co-application of CCPB and Si-NPs, particularly MA34 + 1.5 mM Si-NPs, considerably activated the antioxidant defense system to mitigate the adverse effects of oxidative stress, thus increasing tolerance and enhancing the production of wheat plants in sandy soils under semi-arid environmental conditions

    Outcomes of different aortic arch replacement techniques

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    Background: Consensus on the best treatment for aortic arch pathology is unresolved due to an emerging variety of procedures. We aimed to compare the outcomes of two major techniques for open aortic arch replacement involving the supra-aortic branches and to identify the risk factors for specific adverse events. Methods: Between 1974 and 2017, 172 patients were treated with either the en bloc (island, n = 59; 34.3%) or branched graft technique (n = 113, 65.7%). Most of the patients were treated in an emergent/urgent setting (52.4%). Results: Patients who underwent the en bloc procedure had significantly shorter cardiopulmonary bypass (median: 241 vs 271 minutes, P =.041) and aortic cross clamp times (median: 124 vs 168 minutes, P =.005) than patients who underwent the separate graft technique. Overall, the hospital mortality was lower in the en bloc group, 8.5% vs 19.5%, although the difference was not significant (P =.077). No difference was found in the survival between the separate graft and en bloc groups at 1 (77.0 vs 86.3%), 5 (67.7 vs 66.3%) and 10 years (42.4 vs 51.3%), (P =.63). The postoperative stroke rate was comparable between the en bloc and separate graft cohorts (14.3 vs 19.6%, P =.52). Diabetics and those who underwent an elephant trunk procedure were at a higher risk for reintervention. Conclusions: The separate graft technique, which is more common today, showed no difference from the en bloc technique with regard to hospital mortality and morbidity. Furthermore, the late survival and reintervention rates were similar after both procedures

    Contemporary outcomes after surgical aortic valve replacement with bioprostheses and allografts: ĂźA systematic review and meta-analysis

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    Many observational studies have reported outcomes after surgical aortic valve replacement (AVR), but there are no recent systematic reviews and meta-analyses including all available bioprostheses and allografts. The objective of this study is to provide a comprehensive and up-to-date overview of the outcomes after AVR with bioprostheses and allografts reported in the last 15 years. We conducted a systematic literature review (PROSPERO register: CRD42015017041) of studies published between 2000-15. Inclusion criteria were observational studies or randomized controlled trials reporting on outcomes of AVR with bioprostheses (stented or stentless) or allografts, with or without coronary artery bypass grafting (CABG) or valve repair procedure, with study population size n ≥ 30 and mean follow-up length ≥5 years. Fifty-four bioprosthesis studies and 14 allograft studies were included, encompassing 55 712 and 3872 patients and 349 840 and 32 419 patient-years, respectively. We pooled early mortality risk and linearized occurrence rates of valve-related events, reintervention and late mortality in a random-effects model. Sensitivity, meta-regression and subgroup analyses were performed to investigate the influence of outliers on the pooled estimates and to explore sources of heterogeneity. Funnel plots were used to investigate publication bias. Pooled early mortality risks for bioprostheses and allografts were 4.99% (95% confidence interval [CI], 4.44-5.62) and 5.03% (95% CI, 3.61-7.01), respectively. The late mortality rate was 5.70%/patient-year (95% CI, 4.99-5.62) for bioprostheses and 1.68%/patient-year (95% CI, 1.23-2.28) for allografts. Pooled reintervention rates for bioprostheses and allografts were 0.75%/patient-year (95% CI, 0.61-0.91) and 1.87%/patient-year (95% CI, 1.52-2.31), respectively. There was substantial heterogeneity in most outcomes. Meta-regression analyses identified covariates that could explain the heterogeneity: implantation period, valve type, patient age, gender, pre-intervention New York Heart Association class III/IV, concomitant CABG, study design and follow-up length. There is possible publication bias in all outcomes. This comprehensive systematic review and meta-analysis provides an overview of the outcomes after AVR with bioprostheses and allografts reported during the last 15 years. The results of this study can support patients and doctors in the prosthetic valve choice and can be used in microsimulation models to predict patient outcomes and estimate the cost-effectiveness of AVR with bioprostheses or allografts compared with current and future heart valve prostheses

    Individualized dynamic prediction of survival with the presence of intermediate events

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    Often, in follow-up studies, patients experience intermediate events, such as reinterventions or adverse events, which directly affect the shapes of their longitudinal profiles. Our work is motivated by two studies in which such intermediate events have been recorded during follow-up. In both studies, we are interested in the change of the longitudinal evolutions after the occurrence of the intermediate event and in utilizing this information to improve the accuracy of dynamic prediction of their risk. To achieve so, we propose a flexible joint modeling framework for longitudinal and time-to-event data, which includes features of the intermediate event as time-varying

    Moisture susceptibility of high and low compaction dry process crumb rubber modified asphalt mixtures

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    The field performance of dry process crumb rubber-modified (CRM) asphalt mixtures has been reported to be inconsistent with stripping and premature cracking on the surfacing. One of the concerns is that, because achieving field compaction of CRM material is difficult due to the inherent resilient nature of the rubber particle, nonuniform field compaction may lead to a deficient bond between rubber and bitumen. To assess the influence of compaction, a series of CRM and control mixtures was produced and compacted at two levels: 4% (low, optimum laboratory compaction) and 8% (high, field experience) air void content. The long-term durability, in regard to moisture susceptibility of the mixtures, was assessed by conducting repeated moisture conditioning cycles. Mechanical properties (stiffness, fatigue, and resistance to permanent deformation) were determined in the Nottingham Asphalt Tester. Results indicated that compared with conventional mixtures, the CRM mixtures, regardless of compaction effort, are more susceptible to moisture with the degree of susceptibility primarily depending on the amount of rubber in the mixture, rather than the difference in compaction. This behavior is different from that of conventional mixtures in which, as expected, poorly compacted mixtures were found to be more susceptible to moisture than were well-compacted mixtures
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