339 research outputs found

    A QM/MM approach for the study of monolayer-protected gold clusters

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    We report the development and implementation of hybrid methods that combine quantum mechanics (QM) with molecular mechanics (MM) to theoretically characterize thiolated gold clusters. We use, as training systems, structures such as Au25(SCH2-R)18 and Au38(SCH2-R)24, which can be readily compared with recent crystallographic data. We envision that such an approach will lead to an accurate description of key structural and electronic signatures at a fraction of the cost of a full quantum chemical treatment. As an example, we demonstrate that calculations of the 1H and 13C NMR shielding constants with our proposed QM/MM model maintain the qualitative features of a full DFT calculation, with an order-of-magnitude increase in computational efficiency.Comment: Journal of Materials Science, 201

    Permeable biosorbent barrier for wastewater remediation

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    Chromium is one of the heavy metals that significantly affect water quality in Mongolia. The present study is focused on the remediation of surface water contaminated with chromium (III) by a permeable barrier in order to prevent sediment pollution. The adsorption capacity of the selected materials (13X zeolite and vermiculite) was investigated at different sorbent dosages, pH and initial Cr(III) concentration. The equilibrium adsorption studies showed that vermiculite has a higher Cr(III) removal efficiency in comparison with 13X zeolite. A fungal isolate obtained from the sediment samples collected near Tuul River (Mongolia) was selected from enriched Luria-Bertani medium, showing a good performance for Cr(III) removal (78.2\% for an initial concentration of 50 mg/L). The fungal isolate was genetically typed by DNA sequencing and was identified as belonging to the Alternaria alternata species. 13X zeolite showed the best performance for Cr removal in the permeable barrier assays compared to vermiculite, achieving a total removal of 96\\% and a global uptake of 2.49 mg/g. After 13 days of operation none of the barriers reached saturation with chromium.A previous version of the paper has been presented in the 2nd EWaS International Conference: BEfficient & Sustainable Water Systems Management toward Worth Living Development^, Chania, Crete, Greece, 1-4 June 2016. This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit and COMPETE 2020 (POCI-01-0145-FEDER-006684) and BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020 - Programa Operacional Regional do Norte. Bruna Silva is thankful to the FCT for the concession of a Post-Doc grant (SFRH/BPD/112354/2015). Sampling process was supported by the collaborative research grant of National Academy of Sciences of Taiwan and Science and Technology Foundation of Mongolia, project code NCS-NECS2013003 and co-funded by the Young Scientist Grant (SEAS-2015075) of National University of Mongolia. E. Tuuguu would like to acknowledge the Erasmus-Mundus AREAS+ program for the opportunity to conduct research at CEB-University of Minho.info:eu-repo/semantics/publishedVersio

    ANÁLISIS DE LA SATISFACCIÓN DEL USUARIO EN CENTROS DE SALUD DEL PRIMER NIVEL DE ATENCIÓN EN LA PROVINCIA DE CÓRDOBA, ARGENTINA.

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    Objective: To identify users´ satisfaction about services provide for health centers in the province of Cordoba. Method: Surveys was implemented to the health centers´ users in the the province of Cordoba, asking about sociodemographic aspects, type of health care, motive of consultation, accessibility and general opinion about care received. The information collected was processed and analyzed according to the nature of the variable and comparisons were made by ANOVA and for data categorized coefficient of contingency was utilized (significance level 0.05). Results: Geographic access was considered acceptable by respondents as the waiting time and the conditions buildings. The professional performance during care, the link between the practitioner and users and the service provided by the health center were factors valued by respondents. Conclusion: The analysis of users´satisfaction of health centers is important to provide valid information for generate opportune answers and to optimize the sanitary resources.Objetivo: Identificar el nivel de satisfacción de los destinatarios de los centros de salud de la provincia de Córdoba. Método: Se implementó encuestas a los destinatarios de los centros de salud de la provincia de Córdoba indagando acerca de aspectos sociodemográficos, tipo de asistencia sanitaria, motivo de consulta, accesibilidad y opinión general de la atención recibida. La información recabada fue procesada y analizada de acuerdo a la naturaleza de la variable y las comparaciones se efectuaron por ANOVA y para datos categorizados se utilizó coeficiente de contingencia (nivel de significación 0,05). Resultados: El acceso geográfico fue considerado aceptable por los encuestados al igual que el tiempo de espera y las condiciones edilicias. El desempeño profesional durante la atención, el vínculo establecido entre el profesional y el destinatario y el servicio brindado por el centro de salud fueron factores valorizados por los encuestados. Conclusión: El análisis de la satisfacción de los destinatarios de los centros de salud es importante para proporcionar información válida para generar respuestas oportunas y optimizar los recursos sanitarios

    Solution structure of a repeated unit of the ABA-1 nematode polyprotein allergen of ascaris reveals a novel fold and two discrete lipid-binding sites

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    Parasitic nematode worms cause serious health problems in humans and other animals. They can induce allergic-type immune responses, which can be harmful but may at the same time protect against the infections. Allergens are proteins that trigger allergic reactions and these parasites produce a type that is confined to nematodes, the nematode polyprotein allergens (NPAs). These are synthesized as large precursor proteins comprising repeating units of similar amino acid sequence that are subsequently cleaved into multiple copies of the allergen protein. NPAs bind small lipids such as fatty acids and retinol (Vitamin A) and probably transport these sensitive and insoluble compounds between the tissues of the worms. Nematodes cannot synthesize these lipids, so NPAs may also be crucial for extracting nutrients from their hosts. They may also be involved in altering immune responses by controlling the lipids by which the immune and inflammatory cells communicate. We describe the molecular structure of one unit of an NPA, the well-known ABA-1 allergen of Ascaris and find its structure to be of a type not previously found for lipid-binding proteins, and we describe the unusual sites where lipids bind within this structur

    First enantioseparation and circular dichroism spectra of Au38 clusters protected by achiral ligands

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    Bestowing chirality to metals is central in fields such as heterogeneous catalysis and modern optics. Although the bulk phase of metals is symmetric, their surfaces can become chiral through adsorption of molecules. Interestingly, even achiral molecules can lead to locally chiral, though globally racemic, surfaces. A similar situation can be obtained for metal particles or clusters. Here we report the first separation of the enantiomers of a gold cluster protected by achiral thiolates, Au38(SCH2CH2Ph)24, achieved by chiral high-performance liquid chromatography. The chirality of the nanocluster arises from the chiral arrangement of the thiolates on its surface, forming 'staple motifs'. The enantiomers show mirror-image circular dichroism responses and large anisotropy factors of up to 4×10−3. Comparison with reported circular dichroism spectra of other Au38 clusters reveals that the influence of the ligand on the chiroptical properties is minor

    Nogo-B regulates migration and contraction of airway smooth muscle cells by decreasing ARPC 2/3 and increasing MYL-9 expression

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    <p>Abstract</p> <p>Background</p> <p>Abnormal proliferation, apoptosis, migration and contraction of airway smooth muscle (ASM) cells in airway remodeling in asthma are basically excessive repair responses to a network of inflammatory mediators such as PDGF, but the mechanisms of such responses remain unclear. Nogo-B, a member of the reticulum family 4(RTN4), is known to play a key role in arteriogenesis and tissue repair. Further studies are needed to elucidate the role of Nogo-B in airway smooth muscle abnormalities.</p> <p>Methods</p> <p>A mouse model of chronic asthma was established by repeated OVA inhalation and subjected to Nogo-B expression analysis using immunohistochemistry and Western Blotting. Then, primary human bronchial smooth muscle cells (HBSMCs) were cultured <it>in vitro </it>and a siRNA interference was performed to knockdown the expression of Nogo-B in the cells. The effects of Nogo-B inhibition on PDGF-induced HBSMCs proliferation, migration and contraction were evaluated. Finally, a proteomic analysis was conducted to unveil the underlying mechanisms responsible for the function of Nogo-B.</p> <p>Results</p> <p>Total Nogo-B expression was approximately 3.08-fold lower in chronic asthmatic mice compared to naïve mice, which was obvious in the smooth muscle layer of the airways. Interference of Nogo-B expression by siRNA resulted nearly 96% reduction in mRNA in cultured HBSMCs. In addition, knockdown of Nogo-B using specific siRNA significantly decreased PDGF-induced migration of HBSMCs by 2.3-fold, and increased the cellular contraction by 16% compared to negative controls, but had limited effects on PDGF-induced proliferation. Furthermore, using proteomic analysis, we demonstrate that the expression of actin related protein 2/3 complex subunit 5 (ARPC 2/3) decreased and, myosin regulatory light chain 9 isoform a (MYL-9) increased after Nogo-B knockdown.</p> <p>Conclusions</p> <p>These data define a novel role for Nogo-B in airway remodeling in chronic asthma. Endogenous Nogo-B, which may exert its effects through ARPC 2/3 and MYL-9, is necessary for the migration and contraction of airway smooth muscle cells.</p

    Influence of maternal and social factors as predictors of low birth weight in Italy

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    Abstract Background The purpose of this study is to provide insight into the determinants of low birth weight (LBW) in Italy. Methods The study was carried out in a non-teaching hospital in Catanzaro (Italy). All LBW and very LBW newborns (200) were included in the study and a random sample of 400 newborns weighing ≥ 2500 g was selected. Data were collected from the delivery certificates during one year. Smoking activity of mother and familiar and/or social support during pregnancy was gathered through telephone interviews. Results Overall annual LBW rate was 11.8%. Among LBW newborn there were 125 preterm and 75 term. Younger mothers, those who smoked during pregnancy, and had fewer prenatal care visits were more likely to deliver a LBW child; moreover, preterm newborns, delivered by caesarean section, and twin or multiple birth were significantly more likely to have a LBW. The comparison of very LBW ( Conclusion Several modifiable factors affect the risk of LBW, even when universal access to health care is freely available, but socio-economic status appears to correlate only to very LBW.</p

    The real risks of steroid injection for plantar fasciitis, with a review of conservative therapies

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    This article presents a review of conservative therapies for plantar fasciitis pain reduction with a discussion of steroid therapy risks. The therapies reviewed include orthoses, stretching, extracorporeal shockwave, BTX-A, and corticosteroid injection/iontophoresis. These modes were included based on the availability of double blinded randomized controlled trials. We noted the following findings. Orthoses, regardless of type, can improve pain levels. Plantar stretching shows limited short-term benefit (1 month), but can reflect significant long-term improvement (10 months). Extracorporeal shockwave therapy shows equivocal benefit with some studies showing significant improvement and others showing none. Although BTX-A injections were the least studied, significant pain improvement was demonstrated in the short and long term. Steroid injection/iontophoresis showed significant improvement in the short term (1 month). Steroid therapy, when coupled with plantar stretching, can provide efficacious pain relief; however, steroid injections should be combined with ultrasound monitoring to reduce complications

    Differential Effects of Short Term Feeding of a Soy Protein Isolate Diet and Estrogen Treatment on Bone in the Pre-Pubertal Rat

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    BACKGROUND: Previous reports suggest that beneficial effects of soy on bone quality are due to the estrogenic actions of isoflavone phytochemicals associated with the protein. However, mechanistic studies comparing the effects of soy diet and estrogens on bone, particularly in rapidly growing animals are lacking. METHODOLOGY AND PRINCIPAL FINDINGS: We studied the effects of short term feeding of soy protein isolate (SPI) on bone in comparison to the effects of 17β-estradiol (E2) in pre-pubertal rats. Female rats were weaned to one of 4 treatments: 1) a control casein-based diet (CAS); 2) CAS with subcutaneous E2 (10 µg/kg/d) (CAS+E2); 3) a SPI-containing diet (SPI); or 4) SPI with subcutaneous E2 (SPI) or SPI with 10 µg/kg/d E2 (SPI+E2) for 14 days beginning on postnatal day 20. SPI increased while E2 decreased bone turnover compared to CAS. In contrast, both treatments decreased serum sclerostin levels. Microarray analysis of RNA isolated from bone revealed 652 genes regulated by SPI, 491 genes regulated by E2, and 266 genes regulated by both SPI diet and E2 compared to CAS. The expression of caveolin-1, a protein localized in the cell membrane, was down-regulated (p<0.05) in rats fed SPI, but not by E2 compared to rats fed casein. Down-regulation of caveolin-1 by SPI was associated with increased BMP2, Smad and Runx2 expression in bone and osteoblasts (p<0.05). CONCLUSIONS/SIGNIFICANCE: These results suggest SPI and E2 have different effects on bone turnover prior to puberty. Approximately half of the genes are regulated in the same direction by E2 or SPI, but in combination, SPI blocks the estrogen effects and returns the profile towards control levels. In addition, there are E2 specific and SPI-specific gene changes related to regulation of bone formation
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