142 research outputs found
Compendio de Criterios de Análisis y Diseño de Escaleras de Concreto Reforzado Basado en los Códigos Constructivos que Rigen las Estructuras de Concreto
El presente trabajo fue realizado con un enfoque investigativo y analítico que consolida elementos de Diseño, Tipológico y Estructural para la solución de proyectos de escaleras de hormigón armado, que pretende dar a conocer al estudiante en formación y al investigador relacionado al tema un resumen practico que constituya una herramienta fácil de uso para el diseño de escaleras en edificaciones. El trabajo en su primer capítulo presenta la información básica sobre el tema de escaleras que el autor analizo para la conceptualización del mismo Y que dio curso a sintetizar y exponer caracterizando los elementos de diseño, materiales usados en su construcción y formas de las escaleras que el diseñador debe entender claramente para acometer un proyecto en la forma correcta, esto después de aclarar la base de investigación como lo son los reglamentos de carácter práctico obligatorio.
En el primer capítulo encontramos un resumen de los fundamentos teóricos en el que se basa el diseño de escaleras, involucrando todos los puntos de vista desde donde nace el diseño completo de escaleras, siendo los reglamentos expuestos la piedra angular para esto y otros artículos arquitectónicos de diseño de espacios.
En el capítulo dos se presentan las escaleras desde las algunas maneras en que podríamos agruparlas, con el manejo de los criterios arquitectónicos y estructurales para el diseño de variantes racionales que intervienen en su diseño. El capítulo tres establece las solicitaciones comunes en escaleras, sin dejar de lado la valoración de los fallos más comunes que se presentan en su proceso constructivo con una fundamentación ingeniera para su evaluación. Además se presentan las recomendaciones para el manejo de condicionantes sísmicas en su diseño y construcción.
En el capítulo cuatro se valida como una propuesta de modelación pasando por los reglamentos que definen las consideraciones a tener en el diseño, como lo son las cargas actuantes en el sistema, requisitos minimos de diseño, así como la solución a seguir para el correcto trazado del diseño tipológico de las escaleras de hormigón armado. Aquí se estable el diseño de los elementos que sirven de apoyo al sistema de escaleras y la modelación de las escaleras según cada caso. Con el objetivo de dar a conocer algunos procesos básicos en el cálculo se realizan algunos casos. Además se provee de información relevante en los anexos, como valores que sin duda son de especial ayuda para este tipo de proyectos
Nouvelles méthodes pseudo-MOSFET pour la caractérisation des substrats SOI avancés
Les architectures des dispositifs Silicium-Sur-Isolant (SOI) représentent des alternatives attractives par rapport à celles en Si massif grâce à l amélioration des performances des transistors et des circuits. Dans ce contexte, les plaquettes SOI doivent être d excellente qualité.Dans cette thèse nous développons des nouveaux outils de caractérisation électrique et des modèles pour des substrats SOI avancés. La caractérisation classique pseudo-MOSFET ( -MOSFET) pour le SOI a été revisitée et étendue pour des mesures à basses températures. Les variantes enrichies de -MOSFET, proposées et validées sur des nombreuses géométries, concernent des mesures split C-V et des mesures bruit basse fréquence. A partir des courbes split C-V, une méthode d'extraction de la mobilité effective a été validée. Un modèle expliquant les variations de la capacité avec la fréquence s accorde bien avec les résultats expérimentaux. Le -MOSFET a été aussi étendu pour les films SOI fortement dopés et un modèle pour l'extraction des paramètres a été élaboré. En outre, nous avons prouvé la possibilité de caractériser des nanofils de SiGe empilés dans des architectures 3D, en utilisant le concept -MOSFET. Finalement, le SOI ultra-mince dans la configuration -MOSFET s'est avéré intéressant pour la détection des nanoparticules d'or.Silicon-On-Insulator (SOI) device architectures represent attractive alternatives to bulk ones thanks to the improvement of transistors and circuits performances. In this context, the SOI starting material should be of prime quality.In this thesis, we develop novel electrical characterization tools and models for advanced SOI substrates. The classical pseudo-MOSFET ( -MOSFET) characterization for SOI was revisited and extended to low temperatures. Enriched variants of -MOSFET, proposed and demonstrated on numerous geometries, concern split C-V and low-frequency noise measurements. Based on split C-V, an extraction method for the effective mobility was validated. A model explaining the capacitance variations with the frequency shows good agreement with the experimental results. The -MOSFET was also extended to highly doped SOI films and a model for parameter extraction was derived. Furthermore, we proved the possibility to characterize SiGe nanowire 3D stacks using the -MOSFET concept. Finally thin film -MOSFET proved to be an interesting, technology-light detector for gold nanoparticles.SAVOIE-SCD - Bib.électronique (730659901) / SudocGRENOBLE1/INP-Bib.électronique (384210012) / SudocGRENOBLE2/3-Bib.électronique (384219901) / SudocSudocFranceF
Rezidivierende Serratia-marcescens -Bakteriämie: Wer suchet, der findet
Ein 79-jähriger Patient wird aufgrund einer rezidivierenden Serratia-marcescens- Bakteriämie stationär behandelt. Es konnten eine Infektion der Elektroden des implantierbaren Kardioverter-Defibrillator (ICD) mit septischen pulmonalen Embolien und eine Spondylodiszitis diagnostiziert werden. Zusätzlich zur Antibiotikatherapie erfolgte die komplette Extraktion des ICD-Systems. Bei Patienten mit kardialen elektronischen Implantaten (CIED) und einer nicht hinreichend erklärbaren bzw. rezidivierend auftretenden Bakteriämie, unabhängig davon, um welchen Erreger es sich handelt, muss immer eine CIED-assoziierte Infektion ausgeschlossen werden
The ecacy of an oxidation pond in mineralizing some industrial waste products with special reference to¯uorene degradation: a case study
Abstract The ecacy of the oxidation pond on the outskirts of the 10th of Ramadan, the main industrial city, in Egypt was examined. Samples of wastewater collected from the inlet and the outlet were screened for some priority pollutants. Acenaphthene and¯uor-ene were the most frequently detected polycyclic aromatic hydrocarbons, while dimethyl phthalate was the most frequently detected phthalate ester. The spectrum of pollutants, their concentrations and frequencies were similar in the inlet and the outlet, indicating an inferior mineralization capability of the pond. Several degradative bacterial strains were isolated from the pond and grown on M56 minimal media supplemented with dierent pollutants as the carbon source. The ecacy of pure and mixed cultures to break down¯uorene, the most frequently detected pollutant was examined. Fluorene degradation was fast in the ®rst 10 days, then followed by a slow phase. Mixed culture had a higher rate of¯uorene degradation in comparison to pure cultures. High performance liquid chromatography analysis of¯uorene degradation showed three degradative metabolites. But GC/MS analysis detected one compound, identi®ed as acetamide. The present work has indicated the poor ecacy of the pond. Lack of primary treatment of industrial euent at factory level, coupled with shock loads of toxicants that may damage the microorganisms and their degradative capabilities are presumably main factors behind such inferior performance. Moreover, the type of pollutants discharged into the pond tend to¯uctuate and change depending on the rate from the factories discharge and work shifts. Such irregular feeding of persistent pollutants may have led to a wash out of specialized strains of bacteria capable to degrade such persistent pollutants.
Hepatic gene expression in flounder chronically exposed to multiply polluted estuarine sediment: Absence of classical exposure ‘biomarker’ signals and induction of inflammatory, innate immune and apoptotic pathways
The effects of chronic long term exposure to multiply-polluted environments on fish are not well understood, but environmental surveys suggest that such exposure may cause a variety of pathologies, including cancers. Transcriptomic profiling has recently been used to assess gene expression in European flounder (Platichthys flesus) living in several polluted and clean estuaries. However, the gene expression changes detected were not unequivocally elicited by pollution, most likely due to the confounding effects of natural estuarine ecosystem variables. In this study flounder from an uncontaminated estuary were held on clean or polluted sediments in mesocosms, allowing control of variables such as salinity, temperature, and diet. After 7 months flounder were removed from each mesocosm and hepatocytes prepared from fish exposed to clean or polluted sediments. The hepatocytes were treated with benzo(a)pyrene (BAP), estradiol (E2), copper, a mixture of these three, or with the vehicle DMSO. A flounder cDNA microarray was then used to measure hepatocyte transcript abundance after each treatment. The results show that long term chronic exposure to a multiply-polluted sediment causes increases in the expression of mRNAs coding for proteins of the endogenous apoptotic program, of innate immunity and inflammation. Contrary to expectation, the expression of mRNAs which are commonly used as biomarkers of environmental exposure to particular contaminants were not changed, or were changed contrary to expectation. However, acute treatment of hepatocytes from flounder from both clean and polluted sediments with BAP or E2 caused the expected changes in the expression of these biomarkers. Thus transcriptomic analysis of flounder exposed long-term to chronic pollution causes a different pattern of gene expression than in fish acutely treated with single chemicals, and reveals novel potential biomarkers of environmental contaminant exposure. These novel biomarkers include Diablo, a gene involved in apoptotic pathways and highly differentially regulated by both chronic and acute exposure to multiple pollutants
Towards a System Level Understanding of Non-Model Organisms Sampled from the Environment: A Network Biology Approach
The acquisition and analysis of datasets including multi-level omics and physiology from non-model species, sampled from field populations, is a formidable challenge, which so far has prevented the application of systems biology approaches. If successful, these could contribute enormously to improving our understanding of how populations of living organisms adapt to environmental stressors relating to, for example, pollution and climate. Here we describe the first application of a network inference approach integrating transcriptional, metabolic and phenotypic information representative of wild populations of the European flounder fish, sampled at seven estuarine locations in northern Europe with different degrees and profiles of chemical contaminants. We identified network modules, whose activity was predictive of environmental exposure and represented a link between molecular and morphometric indices. These sub-networks represented both known and candidate novel adverse outcome pathways representative of several aspects of human liver pathophysiology such as liver hyperplasia, fibrosis, and hepatocellular carcinoma. At the molecular level these pathways were linked to TNF alpha, TGF beta, PDGF, AGT and VEGF signalling. More generally, this pioneering study has important implications as it can be applied to model molecular mechanisms of compensatory adaptation to a wide range of scenarios in wild populations
Laparoscopy in management of appendicitis in high-, middle-, and low-income countries: a multicenter, prospective, cohort study.
BACKGROUND: Appendicitis is the most common abdominal surgical emergency worldwide. Differences between high- and low-income settings in the availability of laparoscopic appendectomy, alternative management choices, and outcomes are poorly described. The aim was to identify variation in surgical management and outcomes of appendicitis within low-, middle-, and high-Human Development Index (HDI) countries worldwide. METHODS: This is a multicenter, international prospective cohort study. Consecutive sampling of patients undergoing emergency appendectomy over 6 months was conducted. Follow-up lasted 30 days. RESULTS: 4546 patients from 52 countries underwent appendectomy (2499 high-, 1540 middle-, and 507 low-HDI groups). Surgical site infection (SSI) rates were higher in low-HDI (OR 2.57, 95% CI 1.33-4.99, p = 0.005) but not middle-HDI countries (OR 1.38, 95% CI 0.76-2.52, p = 0.291), compared with high-HDI countries after adjustment. A laparoscopic approach was common in high-HDI countries (1693/2499, 67.7%), but infrequent in low-HDI (41/507, 8.1%) and middle-HDI (132/1540, 8.6%) groups. After accounting for case-mix, laparoscopy was still associated with fewer overall complications (OR 0.55, 95% CI 0.42-0.71, p < 0.001) and SSIs (OR 0.22, 95% CI 0.14-0.33, p < 0.001). In propensity-score matched groups within low-/middle-HDI countries, laparoscopy was still associated with fewer overall complications (OR 0.23 95% CI 0.11-0.44) and SSI (OR 0.21 95% CI 0.09-0.45). CONCLUSION: A laparoscopic approach is associated with better outcomes and availability appears to differ by country HDI. Despite the profound clinical, operational, and financial barriers to its widespread introduction, laparoscopy could significantly improve outcomes for patients in low-resource environments. TRIAL REGISTRATION: NCT02179112
Genomic characterization of SARS-CoV-2 in Egypt: insights into spike protein thermodynamic stability
The overall pattern of the SARS-CoV-2 pandemic so far has been a series of waves; surges in new cases followed by declines. The appearance of novel mutations and variants underlie the rises in infections, making surveillance of SARS-CoV-2 mutations and prediction of variant evolution of utmost importance. In this study, we sequenced 320 SARS-CoV-2 viral genomes isolated from patients from the outpatient COVID-19 clinic in the Children’s Cancer Hospital Egypt 57357 (CCHE 57357) and the Egypt Center for Research and Regenerative Medicine (ECRRM). The samples were collected between March and December 2021, covering the third and fourth waves of the pandemic. The third wave was found to be dominated by Nextclade 20D in our samples, with a small number of alpha variants. The delta variant was found to dominate the fourth wave samples, with the appearance of omicron variants late in 2021. Phylogenetic analysis reveals that the omicron variants are closest genetically to early pandemic variants. Mutation analysis shows SNPs, stop codon mutation gain, and deletion/insertion mutations, with distinct patterns of mutations governed by Nextclade or WHO variant. Finally, we observed a large number of highly correlated mutations, and some negatively correlated mutations, and identified a general inclination toward mutations that lead to enhanced thermodynamic stability of the spike protein. Overall, this study contributes genetic and phylogenetic data, as well as provides insights into SARS-CoV-2 viral evolution that may eventually help in the prediction of evolving mutations for better vaccine development and drug targets
Pooled analysis of who surgical safety checklist use and mortality after emergency laparotomy
Background: The World Health Organization (WHO) Surgical Safety Checklist has fostered safe practice for 10 years, yet its place in emergency surgery has not been assessed on a global scale. The aim of this study was to evaluate reported checklist use in emergency settings and examine the relationship with perioperative mortality in patients who had emergency laparotomy. Methods: In two multinational cohort studies, adults undergoing emergency laparotomy were compared with those having elective gastrointestinal surgery. Relationships between reported checklist use and mortality were determined using multivariable logistic regression and bootstrapped simulation. Results: Of 12 296 patients included from 76 countries, 4843 underwent emergency laparotomy. After adjusting for patient and disease factors, checklist use before emergency laparotomy was more common in countries with a high Human Development Index (HDI) (2455 of 2741, 89⋅6 per cent) compared with that in countries with a middle (753 of 1242, 60⋅6 per cent; odds ratio (OR) 0⋅17, 95 per cent c.i. 0⋅14 to 0⋅21, P < 0⋅001) or low (363 of 860, 42⋅2 percent; OR 0⋅08, 0⋅07 to 0⋅10, P < 0⋅001) HDI. Checklist use was less common in elective surgery than for emergency laparotomy in high-HDI countries (risk difference −9⋅4 (95 per cent c.i. −11⋅9 to −6⋅9) per cent; P < 0⋅001), but the relationship was reversed in low-HDI countries (+12⋅1 (+7⋅0 to +17⋅3) per cent; P < 0⋅001). In multivariable models, checklist use was associated with a lower 30-day perioperative mortality (OR 0⋅60, 0⋅50 to 0⋅73; P < 0⋅001). The greatest absolute benefit was seen for emergency surgery in low-and middle-HDI countries. Conclusion: Checklist use in emergency laparotomy was associated with a significantly lower perioperative mortality rate. Checklist use in low-HDI countries was half that in high-HDI countries
Global economic burden of unmet surgical need for appendicitis
Background: There is a substantial gap in provision of adequate surgical care in many low-and middle-income countries. This study aimed to identify the economic burden of unmet surgical need for the common condition of appendicitis. Methods: Data on the incidence of appendicitis from 170 countries and two different approaches were used to estimate numbers of patients who do not receive surgery: as a fixed proportion of the total unmet surgical need per country (approach 1); and based on country income status (approach 2). Indirect costs with current levels of access and local quality, and those if quality were at the standards of high-income countries, were estimated. A human capital approach was applied, focusing on the economic burden resulting from premature death and absenteeism. Results: Excess mortality was 4185 per 100 000 cases of appendicitis using approach 1 and 3448 per 100 000 using approach 2. The economic burden of continuing current levels of access and local quality was US 73 141 million using approach 2. The economic burden of not providing surgical care to the standards of high-income countries was 75 666 million using approach 2. The largest share of these costs resulted from premature death (97.7 per cent) and lack of access (97.0 per cent) in contrast to lack of quality. Conclusion: For a comparatively non-complex emergency condition such as appendicitis, increasing access to care should be prioritized. Although improving quality of care should not be neglected, increasing provision of care at current standards could reduce societal costs substantially
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