1,065 research outputs found

    Failure to Control Caries in an AIDS-Affected Individual: A Case Report

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    Many patients today are living longer with certain health issues like human immunodeficiency virus (HIV). These patients take numerous medications (HAART: highly active antiretroviral therapy) that cause xerostomia, which increases caries risk. There are particular challenges when treating HIV-positive patients with decreased immune systems, which can also accelerate the progression of periodontal disease. This paper discusses one such case that was followed from 2002 to 2010 at the University of Pittsburgh School of Dental Medicine, where an HIV patient lost all his teeth despite investing thousands of dollars. It is also common sense that just performing restorations to decayed teeth is not enough to control the disease, but recommending a personalized preventive maintenance program to the patient is a must

    Failure to Control Caries in an AIDS-Affected Individual: A Case Report

    Get PDF
    Many patients today are living longer with certain health issues like human immunodeficiency virus (HIV). These patients take numerous medications (HAART: highly active antiretroviral therapy) that cause xerostomia, which increases caries risk. There are particular challenges when treating HIV-positive patients with decreased immune systems, which can also accelerate the progression of periodontal disease. This paper discusses one such case that was followed from 2002 to 2010 at the University of Pittsburgh School of Dental Medicine, where an HIV patient lost all his teeth despite investing thousands of dollars. It is also common sense that just performing restorations to decayed teeth is not enough to control the disease, but recommending a personalized preventive maintenance program to the patient is a must

    Perfil compósito para colector solar, respectivo método de produção e utilização

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    A presente invenção diz respeito a um perfil compósito para caixa modular utilizada em colectores solares para aquecimento de águas para uso doméstico ou industrial cujas principais vantagens passam pela: produção através de um processo de extrusão, redução das perdas energéticas do colector solar devido ao design com perfil alveolar, fácil portabilidade devido a redução do peso por metro quadrado de painel, utilização de compósitos recicláveis na sua composição usando entre outros: borracha de pneu usado reciclada, redução dos tempos de montagem dos colectores solares, eliminação da necessidade de colocação de isolantes adicionais à caixa modular e redução dos custos de produção

    Influence of the chloride attack on the post-cracking behavior of Recycled Steel Fiber Reinforced Concrete

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    The main purpose of the present work is to study the mechanical behavior and durability performance of recycled steel fiber reinforced concrete (RSFRC) under a chloride environment. To this end, the effect of chloride attack on the load-carrying capacity of pre-cracked RSFRC round panels is investigated by performing round panel tests supported on three points (RPT-3ps), considering the influence of the crack width and the fiber distribution/orientation profile. In addition, the influence of the adopted chloride exposure conditions on the post-cracking constitutive laws of the developed RSFRC is also assessed by performing numerical simulations for the prediction of the long-term performance of RSFRC under these aggressive conditions. The tensile stress–crack width relationship of RSFRC is derived by performing an inverse analysis with the RPT-3ps results. The obtained experimental and numerical results show a negligible effect of the chloride attack on the post-cracking behavior of RSFRC for the chloride exposure conditions and pre-crack width levels adopted in this study.This research was funded by C.F. research grant PD/BD/113638/2015 provided by Fundação para a Ciência e a Tecnologia (FCT) through the Doctoral Program in Eco Construction and Rehabilitation–EcoCoRe, and J.B. through the project ICoSyTec (POCI-01-0145-FEDER-027990) financed by FCT and co-funded by FEDER through Operational Competitiveness and Internationalization Programme (POCI)

    Evidences of exopolysaccharide production by Helicobacter pylori submitted to hydrodynamic stress

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    Helicobacter pylori is a widespread Gram-negative bacterium that infects the stomach of humans leading to the onset of several gastric disorders, such as gastritis, gastric ulcers, and cancers. The transmission of H. pylori remains unclear but two different pathways have been suggested: faecal-oral and oraloral. It has been reported that H. pylori has the ability to incorporate in biofilms formed on water-exposed surfaces thus providing a route of infection. On the other hand, a polysaccharide-containing biofilm has been observed at the air-liquid interface when H. pylori is grown in a glass fermenter1. Because exopolysaccharides (EPS) play a determinant role in bacterial adhesion by conferring protection against adverse conditions such as starvation and environmental aggressions, EPS production would be expected to be higher if the bacterium is exposed to water. In this work the capability of H. pylori to produce EPS when exposed to water and under hydrodynamic stress has been evaluated. H. pylori was inoculated in autoclaved distilled water and allowed to stand under gentle stirring at room temperature. The significant and continuous increase in the sugar content 192 hours after inoculation suggests the production of exopolysaccharides. This evidence is reinforced by epiflourescence microscopical observation of the bacteria stained with DAPI (4,6-diamidino-2-phenylindole) that revealed the presence of bacterial aggregates 318 hours after inoculation

    Análisis de los ciclos de congelación y descongelación en la capa activa en el entorno de la BAE JCI. Periodo 2000-2011

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    Close to the Spanish Antarctic Station our research team drilled, at the 1999-2000 Antarctic campaign, a 2,30 m shallow borehole in quartzite bedrock. This borehole was instrumented with temperature data loggers (Tinytag model) that have allowed us to register the gradient thermal in a continuous regime evolution during the 2000-2011 period. The analysis of the temperature data allows to describe the temporal evolution of the freezing and thawing cycles in the active layer, as well as the N-Factor variability, related with the soil surface thermal behavior and its energy balance. In this work we discuss the different freezing and thawing mechanisms in monthly and annual periods. The study shows a important freezing and thawing inter annual variability,, the annual cumulative index showed values in the following intervals: freezing index (-700, -300 ºC day) and thawing index (400, 700 ºC day)

    Material compósito de granulado de borracha de pneus usados reciclado numa matriz polimérica

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    A presente invenção apresenta uma solução que incorpora e melhora a adesão entre o granulado de borracha de pneu usado e a matriz polimérica, pela adição de um agente compatibilizador que para além de compatibilizar os materiais, promove a homogeneidade da mistura e consequentemente obtém-se um material com boas propriedades mecânicas e com bom aspecto superficial. A presente invenção consiste na apresentação de novas formulações de materiais que incorporam borracha de pneu usado em matrizes poliméricas termoplásticas utilizando um agente compatibilizador. Desta mistura obtêm-se produtos com composição de borracha de pneu usado com uma matriz polimérica, recorrendo a aditivos para melhorar as propriedades finais do compósito. O custo é primordial para competir com produtos feitos de matérias virgens e como tal, este processo visa reduzir o custo do produto bem como a quantidade relativa da matéria virgem utilizada e o reaproveitamento da borracha reciclada

    Comparative study of the production of cellulose nanofibers from agro-industrial waste streams of Salicornia ramosissima by acid and enzymatic treatment

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    The study of the suitability of two isolation processes to produce cellulose nanofibers (CNFs) from Salicornia ramosissima waste, with potential applicability as a reinforcing agent of polymeric composites was carried out. To separate the cellulose fibrils from the cell wall and obtain CNFs an alkaline treatment was applied followed by a bleaching treat-ment and, the insoluble residue was next hydrolyzed by either an acid treatment (AT) or an enzyme treatment (ET). SEM and TEM images indicated fiber exposure caused by both treatments. The diameter, length, aspect ratio, and polydispersity index, were measured for both CNFs. CNF (ET) showed high zeta potential values suggesting that ET produces more electrically stable and thinner nanofibers. The FTIR spectra revealed that both treatments effectively removed the amorphous components allowing the CNFs isolation, and XRD patterns evidenced the increase in the degree of crystallinity of both CNFs. Nonetheless, CNF(AT) presented a lower mechanical resistance due to its smaller particle size, compared to the CNF(ET). In summary, the (ET) could successfully isolate CNFs from the Salicornia waste, encouraging the use of this treatment, once when compared to (AT), it does not generate toxic residues, presents mild thermal conditions, and produces CNFs with higher-value applications.info:eu-repo/semantics/publishedVersio

    Submillimetre galaxies reside in dark matter haloes with masses greater than 3 × 10^(11) solar masses

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    The extragalactic background light at far-infrared wavelengths comes from optically faint, dusty, star-forming galaxies in the Universe with star formation rates of a few hundred solar masses per year. These faint, submillimetre galaxies are challenging to study individually because of the relatively poor spatial resolution of far-infrared telescopes. Instead, their average properties can be studied using statistics such as the angular power spectrum of the background intensity variations. A previous attempt at measuring this power spectrum resulted in the suggestion that the clustering amplitude is below the level computed with a simple ansatz based on a halo model. Here we report excess clustering over the linear prediction at arcminute angular scales in the power spectrum of brightness fluctuations at 250, 350 and 500 µm. From this excess, we find that submillimetre galaxies are located in darkmatter haloes with a minimum mass, M_(min), such that log_(10)[M_(min)/M_⊙] = 11.5^(+0.7)_(-0.2) at 350 µm, where M_⊙ is the solar mass. This minimum dark matter halo mass corresponds to the most efficient mass scale for star formation in the Universe, and is lower than that predicted by semi-analytical models for galaxy formation

    Identification of cell-surface mannans in a virulent Helicobacter pylori strain

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    With the intent of contributing to a carbohydrate-based vaccine against the gastroduodenal pathogen, Helicobacter pylori, we report here the structure of cell-surface mannans obtained from a virulent strain. Unlike other wild-type strains, this strain was found to express in good quantities this polysaccharide in vitro. Structural analysis revealed a branched mannan formed by a backbone of α-(1→6)-linked mannopyranosyl residues with approximately 80% branching at the O-2 position. The branches were composed of O-2-linked Man residues in both α- and β-configurations: (image) In addition, this strain also expressed cell-surface emblematic H. pylori lipopolysaccharides (LPS) containing partially fucosylated polyLacNAc O-chains. Affinity assays with polymyxin-B and concanavalin A revealed no association between the mannan and the LPS. The described mannans may be implicated in the mediation of host–microbial interactions and immunological modulation.This work was supported by Fundacao para a Ciencia e Tecnologia (FCT) through project Pylori E&LPS POCI/QUI/56393/2004, PhD grant SFRH/BD/19929/2004, by the Natural Sciences and Engineering Research Council of Canada (NSERC), and by the European Network of Research Infrastructures within the 6th Framework Programme of the EC (Contract # RII3-026145, EU-NMR). The authors further thank Dr. Adrien Favier (RALF-NMR facility, Grenoble - France) for conducting NMR experiments
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