960 resultados para MCM-41 type materials
Resumo:
The function of dowel bars is the transfer of a load across the transverse joint from one pavement slab to the adjoining slab. In the past, these transfer mechanisms have been made of steel. However, pavement damage such as loss of bonding, deterioration, hollowing, cracking and spalling start to occur when the dowels begin to corrode. A significant amount of research has been done to evaluate alternative types of materials for use in the reinforcement of concrete pavements. Initial findings have indicated that stainless steel and fiber composite materials possess properties, such as flexural strength and corrosion resistance, that are equivalent to the Department of Transportation specifications for standard steel, 1 1/2 inch diameter dowel bars. Several factors affect the load transfer of dowels; these include diameter, alignment, grouting, bonding, spacing, corrosion resistance, joint spacing, slab thickness and dowel embedment length. This research is directed at the analysis of load transfer based on material type and dowel spacing. Specifically, this research is directed at analyzing the load transfer characteristics of: (a) 8-inch verses 12-inch spacing, and (b) alternative dowel material compared to epoxy coated steel dowels, will also be analyzed. This report documents the installation of the test sections, placed in 1997. Dowel material type and location are identified. Construction observations and limitations with each dowel material are shown.
Resumo:
The dynamical properties ofshaken granular materials are important in many industrial applications where the shaking is used to mix, segregate and transport them. In this work asystematic, large scale simulation study has been performed to investigate the rheology of dense granular media, in the presence of gas, in a three dimensional vertical cylinder filled with glass balls. The base wall of the cylinder is subjected to sinusoidal oscillation in the vertical direction. The viscoelastic behavior of glass balls during a collision, have been studied experimentally using a modified Newton's Cradle device. By analyzing the results of the measurements, using numerical model based on finite element method, the viscous damping coefficient was determinedfor the glass balls. To obtain detailed information about the interparticle interactions in a shaker, a simplified model for collision between particles of a granular material was proposed. In order to simulate the flow of surrounding gas, a formulation of the equations for fluid flow in a porous medium including particle forces was proposed. These equations are solved with Large Eddy Simulation (LES) technique using a subgrid-model originally proposed for compressible turbulent flows. For a pentagonal prism-shaped container under vertical vibrations, the results show that oscillon type structures were formed. Oscillons are highly localized particle-like excitations of the granular layer. This self-sustaining state was named by analogy with its closest large-scale analogy, the soliton, which was first documented by J.S. Russell in 1834. The results which has been reportedbyBordbar and Zamankhan(2005b)also show that slightly revised fluctuation-dissipation theorem might apply to shaken sand, which appears to be asystem far from equilibrium and could exhibit strong spatial and temporal variations in quantities such as density and local particle velocity. In this light, hydrodynamic type continuum equations were presented for describing the deformation and flow of dense gas-particle mixtures. The constitutive equation used for the stress tensor provides an effective viscosity with a liquid-like character at low shear rates and a gaseous-like behavior at high shear rates. The numerical solutions were obtained for the aforementioned hydrodynamic equations for predicting the flow dynamics ofdense mixture of gas and particles in vertical cylindrical containers. For a heptagonal prism shaped container under vertical vibrations, the model results were found to predict bubbling behavior analogous to those observed experimentally. This bubbling behavior may be explained by the unusual gas pressure distribution found in the bed. In addition, oscillon type structures were found to be formed using a vertically vibrated, pentagonal prism shaped container in agreement with computer simulation results. These observations suggest that the pressure distribution plays a key rolein deformation and flow of dense mixtures of gas and particles under vertical vibrations. The present models provide greater insight toward the explanation of poorly understood hydrodynamic phenomena in the field of granular flows and dense gas-particle mixtures. The models can be generalized to investigate the granular material-container wall interactions which would be an issue of high interests in the industrial applications. By following this approach ideal processing conditions and powder transport can be created in industrial systems.
Resumo:
En aquest treball s'avalua la rehabilitació dels talussos d'una explotació minera carbonífera utilitzant materials de rebuig de la pròpia explotació i provinents d'activitats ramaderes (purins de porc) o urbanes (llots de depuradora), en un ambient àrid del Baix Segre. Les variables analitzades foren el tipus i recobriment vegetals, la penetromia i la salinitat del substrat, i la salinitat, els nitrats i els sediments dels efluents. Els resultats indiquen que és possible rehabilitar els runams en aquests medis, assolint recobriments vegetals fins al 50 % sense que se'n derivin efectes ambientals negatius importants. Taxes altes puntuals d'erosió poden controlar-se amb un disseny adient dels talussos. L'aplicació superficial de purí no té efectes antiencrostants. La moderada salinitat dels substrats condiciona l'establiment de vegetació halòfila.
Resumo:
Inclusive doubly differential cross sections d 2 σ pA /dx F dp T 2 as a function of Feynman-x (x F ) and transverse momentum (p T ) for the production of K S 0 , Λ and Λ¯ in proton-nucleus interactions at 920 GeV are presented. The measurements were performed by HERA-B in the negative x F range (−0.12
Resumo:
La fracture périprothétique du fémur (FPF) représente une complication sérieuse des arthroplasties de hanche. Différents matériels d'ostéosynthèse ont été utilisés pour l'ostéosynthèse des FPFs. Toutefois, aucune étude n'a rapporté les résultats obtenus avec une plaque anatomique non-verrouillée avec des trous excentrés. Les buts de ce travail étaient de présenter 1) le taux de consolidation des FPF traitées par cet implant, 2) les caractéristiques péri-opératoires 3) le taux de complications, et 4) les résultats en terme d'autonomie obtenus après le traitement des FPF du groupe B selon Vancouver avec une plaque anatomique à trous excentrés. Hypothèse L'utilisation de cette plaque permet d'obtenir un taux élevé de consolidation avec un minimum de complications mécaniques. Matériels et Méthodes Quarante-trois patients, d'âge moyen 79 ans ± 13 (41 - 98), qui ont été traités pour une ostéosynthèse d'une FPF de type B selon Vancouver avec cette plaque entre 2002 et 2007 ont été inclus. Les patients ont été classifiées selon les scores ASA et de Charnley. Le temps opératoire, les pertes sanguines chirurgicales, le nombre de transfusion, la durée d'hospitalisation, le délai de consolidation, le lieu de vie ainsi que l'autonomie (score de Parker) ont été évalués. Le taux de survie sans révision a été calculé par la méthode de Kaplan-Meier. Le recul moyen est de 42 mois ± 20 (min - max : 16 - 90). Résultats La consolidation a été obtenue chez tous les patients avec un délai moyen de 2,4 mois ± 0,6 (2-4). 1 patient avec un cal vicieux en varus était à déplorer. Le score de Parker a diminué de 5,93 ± 1,94 (2-9) à 4,93 ± 1,8 (1- 9) (p = 0.01). 2 révisions chirurgicales ont été nécessaires sur la série. Le taux de survie à 5 ans des prothèses après ostéosynthèse de la FPF était de 83,3 % ± 12,6 %. Conclusion Cette plaque anatomique avec trous excentrés permet le traitement des FPF du type B et garantit une consolidation de la fracture avec un faible taux de complications liés à l'ostéosynthèse. Toutefois, les FPF représentent une complication sérieuse des arthroplasties de hanche assortie d'un fort taux de morbidités et de mortalité.
Resumo:
OBJECTIVE: To describe the epidemiology, the surgical treatment, the microbiology, the antibiotic prophylaxis and the outcome of patients with the most severe type of open fractures. METHODS: Retrospective chart reviews of patients with Gustilo type III open fracture admitted to an university hospital in Switzerland between January 2007 and December 2011. The patient's and fracture's characteristics, surgery, antibiotic prophylaxis, and microbiology findings at the initial and at the revision surgery were described. RESULTS: Thirty patients were included (83% male, mean age 41 years). More than half of the patients had polytrauma. In all patients, debridement and stabilization surgery (70% using external fixation) were performed at admission. Soft tissue reconstruction was performed in 87% and in 23% immediate bone graft was performed. Antibiotic prophylaxis were given in all patients for a median duration of 9 days (60% received amoxicillin/clavulanic acid). Positive bacterial culture was found in 53% of the patients at initial surgery and in 88% at revision surgery. At initial and revision surgery, 47% and 88% of the pathogens were amoxicillin/clavulanic acid-resistant. Treatment outcome was favorable in 24 of 30 patients (80%) and in six cases (20%) an amputation had to be performed. None of the patients had chronic bone infection. CONCLUSIONS: Positive cultures were found often in open fractures. Amoxicillin/clavulanic acid which is often mentioned in many guidelines as prophylaxis in open fractures does not cover the most common isolated organisms. The combination of surgery and antibiotic prophylaxis leads to good outcome in Gustilo type III fracture.
Resumo:
AIMS: Smoking cessation has been suggested to increase the short-term risk of type 2 diabetes mellitus (T2DM). This study aimed at assessing the association between smoking cessation and incidence of T2DM and impaired fasting glucose (IFG). METHODS: Data from participants in the CoLaus study, Switzerland, aged 35-75 at baseline and followed for 5.5years were used. Participants were classified as smokers, recent (≤5years), long-term (>5years) quitters, and non-smokers at baseline. Outcomes were IFG (fasting serum glucose (FSG) 5.6-6.99mmol/l) and T2DM (FSG ≥7.0mmol/l and/or treatment) at follow up. RESULTS: 3,166 participants (63% women) had normal baseline FSG, of whom 26.7% were smokers, 6.5% recent quitters, and 23.5% long-term quitters. During follow-up 1,311 participants (41.4%) developed IFG (33.6% women, 54.7% men) and 47 (1.5%) developed T2DM (1.1% women, 2.1% men). Former smokers did not have statistically significant increased odds of IFG compared with smokers after adjustment for age, education, physical activity, hypercholesterolemia, hypertension and alcohol intake, with OR of 1.29 [95% confidence interval 0.94-1.76] for recent quitters and 1.03 [0.84-1.27] for long-term quitters. Former smokers did not have significant increased odds of T2DM compared with smokers with multivariable-adjusted OR of 1.53 [0.58-4.00] for recent quitters and 0.64 [0.27-1.48] for long-term quitters. Adjustment for body-mass index and waist circumference attenuated the association between recent quitting and IFG (OR 1.07 [0.78-1.48]) and T2DM (OR 1.28 [0.48-3.40]. CONCLUSION: In this middle-aged population, smoking cessation was not associated with an increased risk of IFG or T2DM.
Resumo:
Le tabagisme est associé à un risque augmenté de développer un diabète de type 2. Arrêter de fumer devrait donc diminuer le risqué de diabète. Seulement, les études concernant le risque métabolique à l'arrêt du tabac sont discordantes. Par ailleurs, les effets métaboliques du tabac et de l'arrêt du tabac diffèrent probablement selon le sexe, avec notamment un effet différent du tabac sur la santé des femmes, et une prise pondérale plus importante à l'arrêt que chez les hommes. Notre étude vise à évaluer le risque métabolique à l'arrêt du tabac, chez les femmes et les homes séparément. Nous avons utilisé les données de l'étude de cohorte prospective CoLaus, qui évalue différents facteurs de risque cardiovasculaire chez des sujets choisis de manière aléatoire, dans la population Lausannoise entre 35 et 75 ans, suivis sur 5.5 ans en moyenne. Parmi ceux avec une glycémie à jeun normale au départ, nous avons divisé les participants en quatre groupes selon leur statut tabagique : non fumeurs, personnes ayant arrêté de fumer depuis plus de 5 ans, celles ayant arrêté depuis moins de 5 ans, et fumeurs actifs. Nous avons mesuré les incidences de glycémie à jeun altérée (5.6-6.99 mmol/l) et de diabète (glycémie à jeun ≥ 7 mmol/l et/ou traitement pour le diabète) durant le période de suivi, stratifiées par sexe. Puis le risque d'incidence de glycémie altérée et de diabète a été calculé avec trois niveaux d'ajustement pour les facteurs confondants pour un risque métabolique. Nous avons inclus 3166 participants, dont 63% de femmes. Au total, 26.3% étaient fumeurs, 6.5% ex-fumeurs depuis moins de 5 ans et 23.5% ex-fumeurs depuis plus de 5 ans. Durant le suivi, 1311 (41.4%) personnes ont développé une glycémie à jeun altérée (33.6% des femmes, 54.7% des homes), et 47 (1.5%) ont développé un diabète (1.1% des femmes, 2.1% des hommes). Les personnes ayant arrêté de fumer n'avait pas de risque significativement plus élevé de développer une glycémie à jeun altérée ou un diabète que les fumeurs, après ajustement pour l'âge, l'éducation, l'hypercholestérolémie, la prise d'alcool, l'activité physique, la prise de poids, le BMI initial et le BMI d'arrivée dans les différents modèles d'ajustement. L'analyse de l'interaction du sexe avec ces résultats est également négative. Les analyses de sensibilité ont montré que l'exclusion des personnes ayant changé de statut tabagique durant le suivi ne changeait pas ces résultats. Nous avons refait les analyses en incluant les participants ayant une glycémie altérée au début du suivi, mais le risque d'incidence de diabète n'est pas plus élevé chez les ex-fumeurs que chez les fumeurs non plus dans cette population. Sur demande d'un reviewer, nous avons également refait les analyses avec la glycémie en continue (valeurs de base et valeurs à 5.5 ans), et la glycémie moyenne n'était pas différente par groupe de tabagisme. En conclusion, dans cette population européenne d'âge moyen, avec une prévalence basse d'obésité et une prise de poids modérée durant le suivi, nous n'avons pas trouvé de risque significativement plus élevé de développer un diabète en arrêtant de fumer, et ce pour les deux sexes. L'arrêt du tabac doit donc être encouragé chez toutes les fumeuses et tous les fumeurs.
Resumo:
This study aimed at comparing the efficiency of various sampling materials for the collection and subsequent analysis of organic gunshot residues (OGSR). To the best of our knowledge, it is the first time that sampling devices were investigated in detail for further quantitation of OGSR by LC-MS. Seven sampling materials, namely two "swab"-type and five "stub"-type collection materials, were tested. The investigation started with the development of a simple and robust LC-MS method able to separate and quantify molecules typically found in gunpowders, such as diphenylamine or ethylcentralite. The evaluation of sampling materials was then systematically carried out by first analysing blank extracts of the materials to check for potential interferences and determining matrix effects. Based on these results, the best four materials, namely cotton buds, polyester swabs, a tape from 3M and PTFE were compared in terms of collection efficiency during shooting experiments using a set of 9 mm Luger ammunition. It was found that the tape was capable of recovering the highest amounts of OGSR. As tape-lifting is the technique currently used in routine for inorganic GSR, OGSR analysis might be implemented without modifying IGSR sampling and analysis procedure.
Resumo:
UNLABELLED: Cleavage of influenza virus hemagglutinin (HA) by host cell proteases is necessary for viral activation and infectivity. In humans and mice, members of the type II transmembrane protease family (TTSP), e.g., TMPRSS2, TMPRSS4, and TMPRSS11d (HAT), have been shown to cleave influenza virus HA for viral activation and infectivityin vitro Recently, we reported that inactivation of a single HA-activating protease gene,Tmprss2, in knockout mice inhibits the spread of H1N1 influenza viruses. However, after infection ofTmprss2knockout mice with an H3N2 influenza virus, only a slight increase in survival was observed, and mice still lost body weight. In this study, we investigated an additional trypsin-like protease, TMPRSS4. Both TMPRSS2 and TMPRSS4 are expressed in the same cell types of the mouse lung. Deletion ofTmprss4alone in knockout mice does not protect them from body weight loss and death upon infection with H3N2 influenza virus. In contrast,Tmprss2(-/-)Tmprss4(-/-)double-knockout mice showed a remarkably reduced virus spread and lung pathology, in addition to reduced body weight loss and mortality. Thus, our results identified TMPRSS4 as a second host cell protease that, in addition to TMPRSS2, is able to activate the HA of H3N2 influenza virusin vivo IMPORTANCE: Influenza epidemics and recurring pandemics are responsible for significant global morbidity and mortality. Due to high variability of the virus genome, resistance to available antiviral drugs is frequently observed, and new targets for treatment of influenza are needed. Host cell factors essential for processing of the virus hemagglutinin represent very suitable drug targets because the virus is dependent on these host factors for replication. We reported previously thatTmprss2-deficient mice are protected against H1N1 virus infections, but only marginal protection against H3N2 virus infections was observed. Here we show that deletion of two host protease genes,Tmprss2andTmprss4, strongly reduced viral spread as well as lung pathology and resulted in increased survival after H3N2 virus infection. Thus, TMPRSS4 represents another host cell factor that is involved in cleavage activation of H3N2 influenza virusesin vivo.
Resumo:
The void structure of zeolites MCM-22, MCM-36 and ITQ-2 were discussed on the bases of catalytic reaction tests. The hydromerization of n-decane on bifunctional Pt/Zeolite Catalysts have been used as model reactions. Beta and ZSM-5 zeolites were used for comparison. It is concluded that all materials show features of 10MR zeolites and have also pores bigger than 12MR in this order MCM-22
Resumo:
Artificial reefs have barely been used in Neotropical reservoirs (about five studies in three reservoirs), despite their potential as a fishery management tool to create new habitats and also to understand fish ecology. We experimentally assessed how reef material (ceramic, concrete, and PVC) and time modulated fish colonization of artificial reefs deployed in Itaipu Reservoir, a large reservoir of the mainstem Parana´ River, Brazil. Fish richness, abundance, and biomass were significantly greater in the reef treatments than at control sites. Among the experimental reefs, ceramic followed by the concrete treatments were the materials most effectively colonized, harboring the majority of the 13 fish species recorded. Although dependent on material type, many of the regularities of ecological successions were also observed in the artificial reefs, including decelerating increases in species richness, abundance, mean individual size, and species loss rates with time and decelerating decreases of species gain and turnover rates. Species composition also varied with material type and time, together with suites of life history traits: more equilibrium species (i.e., fishes of intermediate size that often exhibit parental care and produce fewer but larger offspring) of the Winemiller-Rose model of fish life histories prevailed in later successional stages. Overall, our study suggests that experimental reefs are a promising tool to understand ecological succession of fish assemblages, particularly in tropical ecosystems given their high species richness and low seasonality
Resumo:
Ring Opening Metathesis Polymerization (ROMP) of cyclic olefins is a powerful transition metal-catalyzed reaction for syntheses of polymers and copolymers. The key feature of this reaction is the [2+2]-cycloaddition mechanism, with retention of the olefinic unsaturation in the polymer chain and occurrence of living polymerization. With the development of metal-carbene type catalysts for this process, many addressed polymeric materials have been successfully prepared to be employed in several fields of the science and technology. This review summarizes recent examples of syntheses of polymers with amphiphilic features such as block, graft, brush or star copolymers; as well syntheses of biomaterials, dendronized architectures, photoactive polymers, cross-linked or self-healing materials, and polymers from renewed supplies.