Cette thèse porte sur la sécurité globale des structures en matériaux hétérogènes saturés soumis à des charges extrêmes, et est appliquée à des problèmes d’interaction fluide-structure, tels que l’interaction barrage-réservoir. Un modèle numérique d’interaction est proposé pour prédire les principales tendances et le comportement général d’un barrage en matériau saturé en interaction avec le réservoir dans des analyses de défaillance d’intérêt pratique. Le modèle numérique proposé est d’abord présenté dans un cadre bidimensionnel (2D), puis étendu à un cadre tridimensionnel (3D). La structure est considérée comme un milieu poreux saturé constitué d’un matériau cohésif. On suppose que le fluide externe en interaction avec la structure agit comme une source de saturation des pores. La réponse de la structure en matériau saturé est décrite avec un modèle lattice discrete couplé de type poutre, basé sur la discrétisation du domaine avec la tessellation de Voronoï, où les liens cohésifs sont représentés par des poutres de Timoshenko non linéaires avec un champ de déplacements enrichi en termes de discontinuités fortes. Le couplage entre la phase solide et le fluide dans les pores est traité avec la théorie de Biot et la loi de Darcy décrivant l’écoulement d’un fluide à travers d’un milieu poreux. La prise en compte numérique du couplage interne ajoute un degré de liberté supplémentaire du type pression à chaque nœud de l’élément fini de Timoshenko, qui est ensuite utilisé pour résoudre les problèmes d’interface entre la structure et le fluide. On considère que le fluide externe dans le réservoir est limité à des petits mouvements, ce qui nous permet de le modéliser avec la théorie des ondes acoustiques. Pour cela, la formulation lagrangienne avec l’approximation mixte déplacement-pression est choisie. Le traitement de l’interface fluide-structure dans le modèle numérique d’interaction est résolu d’une manière simple et efficace. Notamment, les éléments finis de la structure et du fluide externe partagent les mêmes degrés de liberté dans les nœuds communs, permettant ainsi la résolution du système d’équations avec une approche de calcul monolithique. Toutes les implémentations et les simulations numériques sont effectués avec la version recherche du code informatique FEAP (Finite Element Analysis Program). Les modèles numériques proposés pour la structure, le fluide externe et le modèle d’interaction sont validés dans le régime élastique linéaire en comparant les résultats calculés avec les valeurs de référence obtenues soit avec des solutions analytiques, soit avec des modèles continus. Les simulations numériques dans le régime non linéaire ont comme but de démontrer les capacités du modèle proposé de capturer la réponse complète à l’échelle macro et les mécanismes de rupture des structures en matériaux saturés. Enfin, la capacité du modèle d’interaction proposé de traiter la défaillance localisée progressive d’un barrage construit en matériau cohésif poreux sous l’interaction barrage-réservoir a été testé pour un programme de chargement spécifique. Pour prendre en compte les effets de la température, le couplage thermique est introduit dans le modèle numérique de la structure.
Introduction: Inflammatory fibroblast tumor is rare tumor that most often occurs in younger people, usually 30 years old or younger, but most commonly in children age 6-10 years. It usually affects gastrointestinal tract and the lungs but it can also occur in several places at the same time. Clinical manifestations vary depending of the affected system of the body so it is very difficult to determine diagnosis without surgical extirpation and patohistological analysis. Complete surgical resection is curative in most patients and recidivism is rare. Liver abscesses more common occur in females with risk factors and medical history of diabetes, previous liver disease and less likely in patients with granulomatous diseases. Liver abscesses mortality in developing countries is 2-12%, increasing due to open surgical drainage.Case report: We present a 35 years-old patient who was treated at the Clinic for Infectious Diseases University Hospital Mostar and University Hospital Sarajevo, Clinic for Infectious Diseases in August and September 2018 and Clinical Hospital Merkur, Zagreb Surgery Clinic in December 2018. Data was used from medical documentation. Young, immunocompetent patient who was addmited to a hospital following high fever, chills and poor general condition was diagnosed with multiple focal necrotic lesions, differential-diagnostically most likely liver and spleen abscesses with high suspicion of liver malignancy. Liver biopsy was performed and patohistological analysis confirmed the diagnosis of multiple liver abscesses in the IV and VI liver segment, and inflamatory fibroblast tumor in the IV liver segment. Eight weeks of conservative treatment resulted in a complete regression of liver abscesses and inflamatory fibroblast tumor was surgically extirpated at the Clinic Hospital Merkur, Surgery Clinic in the Zagreb in December 2018.Conclusion: An approach to a patient with a multiple liver abscesses and liver tumor requires sub-specialists experience and urgent multidisciplinary diagnostic and treatment approach to prevent further complications and deadly outcome.
Biofuels are environmentally friendly alternative fuels produced from animal and plant raw materials. They have great significance due to limited availability of crude oil and increased ecological requirements. The development of biofuels is followed by the development of new and more efficient analytical procedures for monitoring the composition and physical-chemical properties. This paper presents the application of chromatographic and spectroscopic methods in the analysis of different types of biofuels. The results of the determination of the hydrocarbon composition and functional groups important for the application of biofuels as blending components are shown. In this paper, it has confirmed the possibility of using NMR spectroscopy, HPLC and IC chromatography in biofuel and biomass analysis.
As a type of architectured material, knitted textiles exhibit global mechanical behavior which is affected by their microstructure defined at the scale at which yarns are arranged topologically given the type of textile manufactured. To relate local geometrical, interfacial, material, kinematic and kinetic properties to global mechanical behavior, a first-order, two-scale homogenization scheme was developed and applied in this investigation. In this approach, the equivalent stress at the far field and the consistent material stiffness are explicitly derived from the microstructure. In addition, the macrofield is linked to the microstructural properties by a user subroutine which can compute stresses and stiffness in a looped finite element (FE) code. This multiscale homogenization scheme is computationally efficient and capable of predicting the mechanical behavior at the macroscopic level while accounting directly for the deformation-induced evolution of the underlying microstructure.
Construction materials have a direct impact on the environment, on people, and their health. In addition, building insulation plays a decisive role in terms of energy consumption of buildings and regarding CO2-emissions over their whole life cycle. In order to achieve a holistic concept for green building worldwide, it is necessary to develop ecological insulating materials and to scientifically examine them in terms of their technical properties, as done with particleboards from agricultural waste presented in this article. This study aims to characterize the properties’ tensile and compressive strength, modulus of rupture (MOR), and elasticity (MOE) and thermal conductivity of particleboards affected by parameters, such as waste type (rice straw or flax shives), particleboard density, resin type, and content, as well as the use of treated rice straw. Particleboards made from flax shives had superior properties compared to the rice straw particles. The mechanical properties of the boards increase with an increasing resin content, except for the MOR and MOE, which decrease with an increasing resin content, and reach their peak value at a resin content of 10%.
Abstract Background: Drug-drug interactions are defined as modifications of the drug action that result from the simultaneous administration of another individual drug or several drugs. Nowadays, potential drug-drug interactions (DDIs) are most frequently detected and analyzed using personal digital assistant software programs (online interaction checker tools). Objective: To determine the risk factors for the emergence of all drug-drug interactions in surgical patients with particular emphasis on clinically significant interactions. Patients and methods: This was a retrospective cohort analysis of patients treated at the Surgical Clinic of the Clinical Center Kragujevac. Three interaction checkers were used to reveal drug-drug interactions: Medscape, Epocrates and Micromedex. Results: The study included total of 200 patients, aged 58.54±17.08 years. Average number of drug-drug interactions per patient was between 10.50±9.10 (Micromedex) and 18.75±17.14 (Epocrates). Number of prescribed drugs, antidepressive therapy, antiarrhythmic therapy, number of pharmacological/therapeutic subgroups (2nd level of ATC classification) prescribed, delirium or dementia, diabetes, heart failure, and number of physicians who prescribed drugs to single patient were identified as risk factors for drug-drug interactions while length of hospitalization in days and age of patient in years emerged as protective factors. Conclusion: Drug-drug interactions are relatively common in surgical patients and predisposed by factors such as number of prescribed drugs or drug group per patient, number of physicians who prescribed drugs, antidepressive therapy, antiarrhythmic therapy, presence of delirium or dementia, diabetes and heart failure. On the other hand, prolonged hospitalization and higher age are factors that reduce the risk of interactions in surgical patients.
This paper presents performance analysis of an adaptive peak cancellation (PC) method to reduce the high peak-to-average power ratio (PAPR) for OFDM systems, while keeping the out-of-band (OoB) power leakage as well as an in-band distortion power below the pre-determined level. In this work, the increase of adjacent leakage power ratio (ACLR) and error vector magnitude (EVM) are estimated recursively using the detected peak amplitude. We present analytical framework for OFDM-based systems with theoretical bit error rate (BER) representations and detection of optimum peak threshold based on predefined EVM and ACLR requirements. Moreover, the optimum peak detection threshold is selected based on theoretical design to maintain the pre-defined distortion level. Thus, their degradations are restricted below the pre-defined levels which correspond to target OoB radiation. We also discuss the practical design of peak-cancellation signal with target OoB radiation and in-band distortion through optimizing the windowing size of the PC signal. Numerical results show the improvements with respect to both achievable BER and PAPR with the PC method in eigen-beam space division multiplexing (E-SDM) systems under restriction of OoB power radiation. It can also be seen that the theoretical BER shows good agreements with simulation results.
Every successful health care system should be based on some general humanistic ideals. However, the nationally organized health care systems of most European countries usually suffer from a deficiency in common ethical values based on universal human principles. When transitional societies, such as that of Bosnia-Herzegovina are concerned, health care organizational models are even more dysfunctional. The sources of a dysfunction in medical care system of Bosnia-Herzegovina are manifold and mutually controversial, including a lack of shared principles, an inappropriate involvement of politicians in medical care and practice, administrative difficulties arising from superficial communication systems, as well as economic limits concerned with the financing of health care. The deficiency of a moral culture of medicine, which is correlated to a general collapse of morality is also responsible for many problems affecting various aspects of life including medical care. Hence, medical ethics from a virtue perspective is becoming an important ingredient of any improvement deigned to provide better-quality medical care. The aim of this paper is to underline the influence of humanism on the organization of health care systems and the ethics of medical interrelations in the society of Bosnia-Herzegovina. It is not intended to diagnose or resolve the problems, but to analyze them. It is also a critique of specific socio-political-economic influences on this health care system, inquiring if well-educated individuals in the virtues, which are involved in medical practice and education, would counteract them. In conclusion, humanism creates a universal ethical structure, which is based on human values such as fidelity, trust, benevolence, intellectual honesty, courage, compassion and truthfulness. These values should represent the standard around which medical care is organized. Since the health care system in Bosnia-Herzegovina is not entirely founded upon humanistic ideals, addressing the socio-political-economic conditions that constantly undermine those values is a prerequisite for any much-needed improvements of the medical care.
Introduction: Although many predictive tools have already been developed, efforts are still proceeding to identify a reliable biomarker to predict the prognosis of the patients with acute heart disorders. Objectives: The aim was to evaluate the role of renal injury biomarkers (serum cystatin C, serum and urine interleukin-18, IL-18) and heart failure biomarkers (plasma B-type natriuretic peptide, BNP) in the prediction of the postdischarge requirement of renal replacement therapy (RRT) and/or 6-month mortality in patients with acute heart disorders. Patients and Methods: In patients diagnosed with acute heart disorders (acute heart failure [AHF] and/or acute coronary syndrome [ACS]) and admitted to the intensive care units, baseline clinical parameters, renal and cardiac biomarkers were determined. Patients were followed up for 6 months. The composite outcome was the postdischarge requirement of RRT and/or 6-month mortality. Results: Of 120 patients, 5.8% continued RRT after discharge. The 6-month mortality was 20%. Cox logistic regression analysis showed that urine IL-18 (P=0.021), plasma BNP (P=0.046), Acute Physiology and Chronic Health Evaluation (APACHE) II score (P=0.002), and left ventricular diastolic dysfunction (P=0.045) were independent predictors of the postdischarge requirement of RRT and/or 6-month mortality. For predicting RRT and/or 6-month mortality, using urine IL-18 cutoff value of 29.1 pg/mL showed 66.7% sensitivity and 67.7% specificity (area under the curve, AUC 0.70, P=0.003), while using plasma BNP cutoff value of 881.6 pg/mL showed 66.7% sensitivity and 70.8% specificity (AUC 0.76, P<0.001). Conclusion: Urine IL-18 and plasma BNP are independently predictive for the postdischarge requirement of RRT and/or 6-month mortality in patients with acute heart disorders.
Objective – The aim of this article is to present a case of POTS, which was diagnosed quickly with Holter ECG and whose symptoms improved promptly and dramatically with non-pharmacological therapy. Case Presentation – A 15-year-old female patient mother was admitted because of unusual episodes of dizziness, syncope with spontaneous recovery and palpitations. Most of these symptoms occurred fairly frequently on standing. The Holter ECG was done with recommendation to perform some activities during recording, such as to stand for ten minutes in the presence of another person and to write symptoms. It was noticed on the Holter ECG that she had increase in heart rate more than 60 beats per minute during these ten minutes followed by symptoms. The patient was diagnosed with POTS and nonpharmacological therapy was advised which was successful. Conclusion – POTS is a disabling condition with heterogeneous and atypical symptoms which mostly affects the young females. Sometimes, a long period of time is necessary to diagnose POTS. Therefore, it is important to diagnose quickly and to start with appropriate therapy which is unique for every POTS patient. Delay in diagnosis and treatment can lead to further disability in patients affected by POTS and their poor quality of life.
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