235 research outputs found

    Computational modeling of nanodrug-induced effects on cardiac electromechanics

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    This work generally aims to promote the use of computational models for predicting side effects of nanodrugs under development, as a means to speed up the cycle of drug development, with potential savings on testing, and reduction in the need for animal or human testing. The specific objective of this thesis has been to accurately model a single ventricular contraction-relaxation cycle, and monitor the effects induced by nanodrugs on the electro-mechano-physiology of the left and right ventricles. Nanodrug interaction with ion channels located on cardiac cell membranes, such as those for sodium, potassium and calcium, can distort an electrical wave propagating through the tissue and can affect cardiac macroscale functions. In this study, a material model after Holzapfel and Ogden was developed to account for the anisotropic hyperelastic behavior of cardiac tissue, which was implemented on the open source software library Chaste. A coupled drug-electro-mechano-physiological system was then set up, also on Chaste, where a nanodrug effect was introduced into the cellular structure (nanoscale) as an ion channel inhibitor, and its influence then solved for, with respect to resulting electro-mechanical ventricular behaviors. Using quantifiable biomarkers, these effects were compared to the literature and clinical data. In this work we identified the following main results. Nanodrugs causing sodium channel blockage were found to produce the anticipated delays in electro-mechanics. Our study further predicted additional effects on LV twisting and LV & RV strain. On the other hand, nanodrugs causing potassium and calcium channel blockage revealed that cardiac mechanics is less responsive to mild alterations in electrophysiology, than electrophysiology is to ionic changes. Nonetheless, it is important to quantify these changes, as even a very small deviation from normal could accumulate over multiple cardiac cycles, and lead to adverse consequences on cardiac health in the long term

    Nurses' Perceptions of Patient Safety Culture in Intensive Care Units: A Cross-Sectional Study

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    BACKGROUND: Patient safety culture is a relatively new focus where little is known about its current status in Egypt’s teaching hospitals, mainly intensive care units (ICUs). Therefore, the authors of this study attempted to assess the patient safety culture dimensions from the nurses’ perspective. METHODS: An exploratory cross-sectional study was conducted in two ICUs (pediatric ICU and adult ICU) at the University Hospital over 3 months from October till December 2018. Sixty nurses were interviewed using the Hospital Survey on Patient Safety Culture. RESULTS: The current study findings revealed an average positive response to individual items ranging from 6% to 51%. The “Organizational learning†dimension had the highest average percent positive patient safety dimension score (51%) among all respondents, while the “Frequency of events reported†dimension had the lowest one (6%). No statistically significant difference was reported between the pediatric and adult ICUs for all mean scores except for the “Non-punitive response to error†dimension which was reported to be greater in the pediatric intensive care unit (PICU) compared to adult ICU (P < 0.005). The overall patient safety grade was rated acceptable by 47.5% of the interviewed nurses. CONCLUSION: The current study shows that patient safety is fragile in ICUs, and more effort is recommended to increase the awareness of health care providers. Also, hospital managers need to enhance the performance and practices of patient safety within a non-punitive reporting environment

    Strangeness Enhancement at LHC Energies using the thermal model and EPOSLHC event-generator

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    The strangeness enhancement signature of QGP formation at LHC energies is carefully tackled in the present study. Based on HRG, the particle ratios of mainly strange and multi-strange particles are studied at energies from lower s\sqrt{s}\sim 0.001 up to 13 TeV. The strangeness enhancement clearly appeared at more higher energies, and the ratios are confronted to the available experimental data. The particle ratios are also studied using the Cosmic Ray Monte Carlo (CRMC) interface model with its two different event generators namely; EPOS 1.991.99 and EPOSlhc which show a good agreement with the model calculations at the whole range of the energy. We utilize to produce some ratios. EPOS 1.991.99 is used to estimate particle ratios at lower energies from AGS up to the Relativistic Heavy Ion Collider (RHIC) while EPOSlhc is used at LHC energies. The production of kaons and lambda particles is studied in terms of the mean multiplicity in p-p collisions at energies ranging from 4 - 26 GeV. We find that both HRG model and the used event generators, EPOS 1.991.99 and EPOSlhc, can describe the particle ratios very well. Additionally, the freeze-out parameters are estimated for different collision systems, such as p-p and Pb-Pb, at LHC energies using both models.Comment: 9 page

    A Review on the Cerebrovascular Segmentation Methods

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    © 2018 IEEE. This paper explores various methods that have been proposed for the segmentation of the cerebrovascular structure. All of the methods listed are a combination old, new, automatic and semiautomatic models that produce promising results. Each method will be explained along with its advantages and disadvantages. Each of the methods explained are further explored in this paper with variety algorithms produced by using certain models to target certain areas in the cerebrovascular structure. These algorithms were developed to segment cerebrovascular structures from scans obtained from various image modalities e.g., time of flight magnetic-resonance angiography (TOF-MRA), and computed tomography angiography (CTA)

    Particle production and chemical freezeout from the hybrid UrQMD approach at NICA energies

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    The energy dependence of various particle ratios is calculated within the Ultra-Relativistic Quantum Molecular Dynamics approach and compared with the hadron resonance gas (HRG) model and measurements from various experiments, including RHIC-BES, SPS and AGS. It is found that the UrQMD particle ratios agree well with the experimental results at the RHIC-BES energies. Thus, we have utilized UrQMD in simulating particle ratios at other beam energies down to 3 GeV, which will be accessed at NICA and FAIR future facilities. We observe that the particle ratios for crossover and first-order phase transition, implemented in the hybrid UrQMD v3.4, are nearly indistinguishable, especially at low energies (at large baryon chemical potentials or high density).Comment: 13 pages, 5 figures, 2 tables, one reference is added and one paragraph is rephrased. To appear in EPJ

    Anti-inflammatory and Antioxidant Effects of Grapefruit Juice on Ulcerative Colitis induced by Acetic Acid in Rats

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    Grapefruit is commonly consumed around the world due to its nutritional and medicinal properties. Ulcerative colitis (UC) accounts for an inflammatory bowel disease (IBD) accompanied by irritation, recurrent inflammation, and ulceration of the colon's mucosa. Our objective was to assess the antiinflammatory and antioxidant impacts of grapefruit juice (GFJ) in rat with UC induced by acetic acid (AA). There were five groups made up of 35 mature male rats. Group 2 served as a positive control with UC, whereas group 1 was preserved as a negative control. For 8 weeks, groups 3, 4, and 5 received UC while also given 2.5, 5 or 10% of GFJ orally. Feed efficiency ratio (FER), body weight growth (BWG), and feed intake (FI) were computed. From rat eye orbital plexuses blood samples were taken to separate the serum after centrifugation.  The aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activity were assessed utilizing serum samples. The antioxidant enzymes catalase (CAT), glutathione peroxidase (GPx), and superoxide dismutase (SOD) in serum were quantified. Serum inflammatory cytokines as tumor necrosis factor alpha (TNFα), interleukin 1 β (IL1 β), IL6 and IL8, as well as triglycerides (TG) and total cholesterol (TC) were measured. In liver homogenate, glutathione (GSH) and malondialdehyde (MDA) were determined. Additionally, histopathology of the colon was accomplished. Our findings specified that GFJ at 10% significantly decreased FI, BWG and FER, cytokines TNFα, IL1 β, IL6 and IL8 and TC and TG. Relative to the positive controls, the rats treated with GFJ exhibited elevated serum concentrations of SOD, GPx, and CAT enzymes. Liver GSH was elevated and MDA was reduced. Histopathological examination of the colon showed that GFJ at 10% reduced ulcerative colitis. Because grapefruit juice has strong anti-inflammatory and antioxidant characteristics and reduces oxidative stress and inflammation in rats, grapefruit juice, at a concentration of 10%, likely protects against ulcerative colitis. Patients with ulcerative colitis may find it helpful to consume grapefruit juice as a beverage.&nbsp

    A Painless Thoracic Aortic Dissection

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    Thoracic aortic dissection (TAD) has a very high mortality rate and is often missed due to the atypical presentation of patients. We present a case of a man with chronic hypertension, atrial fibrillation (AF) (on regular warfarin) and a previous endovascular aneurysm repair (EVAR), who presented with dyspepsia and was incidentally found to have a ruptured distal thoracic aneurysm on imaging with no obvious clinical signs on examination, nor abnormalities on admission chest x-ray (CXR)

    Association between aortic sclerosis and coronary artery disease

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    Background: Although there is a recognized link between cardiovascular hazards and coronary artery disease (CAD), it is still unknown whether aortic sclerosis and CAD are linked.Objective: This study aimed to check whether if there is a link between aortic sclerosis and the existence and severity of coronary artery disease .Patients and methods: 204 individuals were enrolled in the study, transthoracic echocardiographic, and coronary angiography were done. Aortic leaflets were tested for the amount of thickness in the short axis view. The involvement of coronary arteries represented by the gensini score and the association between aortic valve sclerosis score and the degree and severity of coronary affection was investigated using the Gensini score.Results: The individuals were divided into 2 groups grounded on the severity of aortic valve sclerosis. Group A (GP A) included patients with aortic valve sclerosis (AVS) ≥ 2 and group B (GP B) included patients with AVS < 2. In GP A, the right coronary cusp was the most afflicted one, whereas the LAD was the most affected in coronaries. The degree and severity of CAD were more significant in GP A, as evidenced by a higher Gensini score value of 39.27 versus 28.84 in GP B.Conclusion: AVS has been found to be correlated with the presence and severity of CAD and could be used as a potential surrogate marker for the illness

    Configuration design and performance analysis of a fast frequency modulation optical CDMA communication system

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    A fast frequency modulation optical code division multiple access (CDMA) communication system is proposed. In this system, an electrically controlled tunable optical filter (TOF) is used to encode the modulated broadband light source. The code depends on the function set to the controller. Two-dimensional functional code is also proposed based of shifted sine function. The function defines the dynamic coding pattern of the central wavelength of the transmitted narrowband optical signal. The system allows for an easy reconfiguration of the transmitter without the need for sophisticated encoder. At the receiver, a synchronized TOF with the same function is used as a decoder. The performance of this system is shown to be better compared with a fast frequency hopping and a spectral amplitude coding systems
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