498 research outputs found

    Lung protection in cardio-pulmonary bypass

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    Since the invention of the heart-lung machine paediatric cardiac surgery developed rapidly. For correction of complex cardiac malformations the application of a cardio-pulmonary bypass (CPB) has become indispensable but possible negative effects of this technique should not be neglected. Especially, both bypassed organs i.e. heart and lung are not perfused during the procedure and therefore are threatened by ischemia and reperfusion injury. Additionally, CPB was developed with a non-pulsatile flow but there are clinical observations that pulsatile flow might be superior with improved patient outcomes. Thus, the aim of our study was to evaluate the effect of CPB on lung structure and to assess whether different flow modalities (pulsatile vs. non-pulsatile flow) or application of the antibiotic minocycline might be advantageous. Thirty five piglets of four weeks age were examined and divided into five experimental groups: control (no CPB) without or with minocycline, CPB (non-pulsatile flow) without or with minocycline and CPB with pulsatile flow. CPB was performed for 90 min followed by a 120 min reperfusion and recovery phase. Thereafter, adenosine triphosphate-content of lung biopsies and histology was carried out. We found that CPB was associated with a significant thickening of alveolar wall accompanied by an infiltration of neutrophil leucocytes. Moreover, markers for hypoxia, apoptosis, nitrosative stress, inflammation and DNA damage were significantly elevated after CPB. These cellular damages could be partially inhibited by minocycline or pulsatile flow. Both, minocycline and pulsatile flow attenuate lung damage after CPB

    Insertion Detection System Employing Neural Network MLP and Detection Trees Using Different Techniques

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    by addressing intruder attacks, network security experts work to maintain services available at all times. The Intrusion Detection System (IDS) is one of the available mechanisms for detecting and classifying any abnormal behavior. As a result, the IDS must always be up to date with the most recent intruder attack signatures to maintain the confidentiality, integrity, and availability of the services. This paper shows how the NSL-KDD dataset may be used to test and evaluate various Machine Learning techniques. It focuses mostly on the NLS-KDD pre-processing step to create an acceptable and balanced experimental data set to improve accuracy and minimize false positives. For this study, the approaches J48 and MLP were employed. The Decision Trees classifier has been demonstrated to have the highest accuracy rate for detecting and categorizing all NSL-KDD dataset attacks

    Upper critical field divergence induced by mesoscopic phase separation in the organic superconductor (TMTSF)2ReO4

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    Due to the competition of two anion orders, (TMTSF)2ReO4, presents a phase coexistence between semiconducting and metallic (superconducting) regions (filaments or droplets) in a wide range of pressure. In this regime, the superconducting upper critical field for H parallel to both c* and b' axes present a linear part at low fields followed by a divergence above a cross-over field. This cross-over corresponds to the 3D-2D decoupling transition expected in filamentary or granular superconductors. The sharpness of the transition also demonstrates that all filaments are of similar sizes and self organize in a very ordered way. The distance between the filaments and their cross-section are estimated.Comment: 4 pages, 4 figure

    Adhesion mechanisms of the contact interface of TiO2 nanoparticles in films and aggregates

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    Fundamental knowledge about the mechanisms of adhesion between oxide particles with diameters of few nanometers is impeded by the difficulties associated with direct measurements of contact forces at such a small size scale. Here we develop a strategy based on AFM force spectroscopy combined with all-atom molecular dynamics simulations to quantify and explain the nature of the contact forces between 10 nm small TiO2 nanoparticles. The method is based on the statistical analysis of the force peaks measured in repeated approaching/retracting loops of an AFM cantilever into a film of nanoparticle agglomerates and relies on the in-situ imaging of the film stretching behavior in an AFM/TEM setup. Sliding and rolling events first lead to local rearrangements in the film structure when subjected to tensile load, prior to its final rupture caused by the reversible detaching of individual nanoparticles. The associated contact force of about 2.5 nN is in quantitative agreement with the results of molecular dynamics simulations of the particle–particle detachment. We reveal that the contact forces are dominated by the structure of water layers adsorbed on the particles’ surfaces at ambient conditions. This leads to nonmonotonous force–displacement curves that can be explained only in part by classical capillary effects and highlights the importance of considering explicitly the molecular nature of the adsorbates

    Knowledge and Attitudes of Young People toward Mental Illness: A Cross Sectional Study

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    The aim of the study was to investigate young Jordanians’ knowledge and attitudes toward people who have a mental illness. A cross sectional design was utilized. A convenient sample of 858 participants aged between 15–24 years old completed a survey. Participants under 19 years were accessed through their schools and those 19 years and above were accessed through universities. Results showed that although the majority of university and school students’ responses were generally consistent, they disagreed on 11 items on the survey; for example, 186 (39.3%) of university students agreed that mental illness has a biological origin compared with only 119 (30%) of school students. The majority of young people 737 (85.9%) were willing to learn and 792 (92.3%) felt that they have to help people with mental illness, which make them willing to learn. In conclusion, the findings provide insights for decision makers and researchers in Jordan about young peoples’ knowledge and attitudes toward mental illness. Increasing young adults’ literacy through introducing educational programs such as mental health first aid courses will enrich their knowledge; help change attitudes and reduce stigma toward people living with mental illness

    Ab initio studies of electronic structure of defects in PbTe

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    Understanding the detailed electronic structure of deep defect states in narrow band-gap semiconductors has been a challenging problem. Recently, self-consistent ab initio calculations within density functional theory (DFT) using supercell models have been successful in tackling this problem. In this paper, we carry out such calculations in PbTe, a well-known narrow band-gap semiconductor, for a large class of defects: cationic and anionic substitutional impurities of different valence, and cationic and anionic vacancies. For the cationic defects, we study a series of compounds RPb2n-1Te2n, where R is vacancy or monovalent, divalent, or trivalent atom; for the anionic defects, we study compounds MPb2nTe2n-1, where M is vacancy, S, Se or I. We find that the density of states (DOS) near the top of the valence band and the bottom of the conduction band get significantly modified for most of these defects. This suggests that the transport properties of PbTe in the presence of impurities can not be interpreted by simple carrier doping concepts, confirming such ideas developed from qualitative and semi-quantitative arguments

    Selective arterialization of a cardiac vein in a model of cardiac microangiopathy and macroangiopathy in sheep

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    ObjectiveSome patients with significant arteriosclerosis of the heart are not amenable to revascularization of a coronary artery because they have a combination of microangiopathy and significant macroangiopathy. We investigated the benefit of arterialization of a cardiac vein under these circumstances in an acute animal model.MethodsIn the hearts of 8 sheep, microspheres were injected into the left coronary artery; 60 minutes later, a stenosis of the left anterior descending artery was performed. After 45 minutes, retrograde venous revascularization was performed by sewing the left internal thoracic artery to the concomitant vein of the left anterior descending artery in a beating-heart technique. For flow reversal, the vein was ligated proximally to the anastomosis. The efficiency of the bypass graft was evaluated by coronary angiography and flow measurement. Cardiac output, electrocardiography, and mean arterial blood pressure were assessed in each phase of the experiment.ResultsThe ischemic state of the myocardium was confirmed by a significant decrease of cardiac output, stroke volume, and mean arterial blood pressure, and a significant elevation of the ST segment in the electrocardiography. After retrograde venous revascularization was established, cardiac output and stroke volume increased and ST elevations decreased. The grafts showed adequate flow (26.15 ± 2.08 mL/min), and reversed blood flow in the grafted vein was proved by coronary angiography.ConclusionRetrograde venous revascularization is possible and improves cardiac function in a state of acute ischemia caused by a combination of microangiopathy and macroangiopathy

    Optimal controllers and configurations of 100% PV and energy Storage systems for a microgrid : the case study of a small town in Jordan

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    Renewable energy systems such as Photovoltaic (PV) have become one of the best options for supplying electricity at the distribution network level. This is mainly because the PV system is sustainable, environmentally friendly, and is a low-cost form of energy. The intermittent and unpredictable nature of renewable energy sources which leads to a mismatch between the power generation and load demand is the challenge to having 100% renewable power networks. Therefore, an Energy Storage System (ESS) can be a significant solution to overcome these challenges and improve the reliability of the network. In Jordan, the energy sector is facing a number of challenges due to the high energy-import dependency, high energy costs, and the inadequate electrification of rural areas. In this paper, the optimal integration of PV and ESS systems is designed and developed for a distribution network in Jordan. The economic and energy performance of the network and a proposed power network under different optimization algorithms and power network operation scenarios are investigated. Metaheuristic optimization algorithms, namely: Golden Ratio Optimization Method (GROM) and Particle Swarm Optimization (PSO) algorithms, are employed to find the optimal configurations and integrated 100% PV and ESS for the microgrid

    Survey instruments used in clinical and epidemiological research on waterpipe tobacco smoking: a systematic review

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    <p>Abstract</p> <p>Background</p> <p>The primary objective was to systematically review the medical literature for instruments validated for use in epidemiological and clinical research on waterpipe smoking.</p> <p>Methods</p> <p>We searched the following databases: MEDLINE, EMBASE, and ISI the Web of Science. We selected studies using a two-stage duplicate and independent screening process. We included papers reporting on the development and/or validation of survey instruments to measure waterpipe tobacco consumption or related concepts. Two reviewers used a standardized and pilot tested data abstraction form to collect data from each eligible study using a duplicate and independent screening process. We also determined the percentage of observational studies assessing the health effects of waterpipe tobacco smoking and the percentage of studies of prevalence of waterpipe tobacco smoking that have used validated survey instruments.</p> <p>Results</p> <p>We identified a total of five survey instruments. One instrument was designed to measure knowledge, attitudes, and waterpipe use among pregnant women and was shown to have internal consistency and content validity. Three instruments were designed to measure waterpipe tobacco consumption, two of which were reported to have face validity. The fifth instrument was designed to measure waterpipe dependence and was rigorously developed and validated. One of the studies of prevalence and none of the studies of health effects of waterpipe smoking used validated instruments.</p> <p>Conclusions</p> <p>A number of instruments for measuring the use of and dependence on waterpipe smoking exist. Future research should study content validity and cross cultural adaptation of these instruments.</p

    Intranasal Administration as a Route for Drug Delivery to the Brain: Evidence for a Unique Pathway for Albumin

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    A variety of compounds will distribute into the brain when placed at the cribriform plate by intranasal (i.n.) administration. In this study, we investigated the ability of albumin, a protein that can act as a drug carrier but is excluded from brain by the blood-brain barrier, to distribute into the brain after i.n. administration. We labeled bovine serum albumin with [125I] ([125I]Alb) and studied its uptake into 11 brain regions and its entry into the blood from 5 minutes to 6 hours after i.n. administration. [125I]Alb was present throughout the brain at 5 minutes. Several regions showed distinct peaks in uptake that ranged from 5 minutes (parietal cortex) to 60 minutes (midbrain). About 2–4% of the i.n. [125I]Alb entered the bloodstream. The highest levels occurred in the olfactory bulb and striatum. Distribution was dose-dependent, with less taken up by whole brain, cortex, and blood at the higher dose of albumin. Uptake was selectively increased into the olfactory bulb and cortex by the fluid-phase stimulator PMA (phorbol 12-myristate 13-acetate), but inhibitors to receptor-mediated transcytosis, caveolae, and phosphoinositide 3-kinase were without effect. Albumin altered the distribution of radioactive leptin given by i.n. administration, decreasing uptake into the blood and by the cerebellum and increasing uptake by the hypothalamus. We conclude that [125I]Alb administered i.n. reaches all parts of the brain through a dose-dependent mechanism that may involve fluid-phase transcytosis and, as illustrated by leptin, can affect the delivery of other substances to the brain after their i.n. administration
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