196 research outputs found

    Hybrid magnetic graphitic nanocomposites for catalytic wet peroxide oxidation applications

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    Fe3O4, with a lattice parameter a = 8.357 A and average particle size of 12.5 +/- 3.6 nm, was successfully encapsulated within a graphitic structure by a hierarchical co-assembly approach, followed by thermal annealing. The resulting material was denoted as MGNC-magnetic graphitic nanocomposite. MGNC possesses average core size of 109 +/- 35 nm (mainly composed by agglomerates of magnetic nanoparticles), stability up to 400 degrees C under oxidizing atmosphere, a micro-mesoporous structure with a fairly developed specific surface area (S-BET = 330 m(2) g(-1)) and neutral character (pH(PZC) = 7.1). Catalytic wet peroxide oxidation (CWPO) experiments performed with a 4-nitrophenol (4-NP)/Fe3O4 mass ratio fixed at 36.6, allowed to achieve high efficiency of catalyst usage throughout the wide range of 4-NP concentration considered (200 mg L-1-5 g L-1). The inclusion of Fe3O4 nanoparticles in a graphitic structure during the synthesis of MGNC was found to (i) enhance the catalytic activity in CWPO when compared to Fe3O4, due to increased adsorptive interactions between the surface of the catalyst and the pollutant molecules, while (ii) strongly limiting the leaching of Fe species from Fe3O4 to the treated water, due to the confinement effect caused by the carbon shell. As a result of these effects, unprecedented pollutant mass removals were obtained ranging from 5000 mg(-1) h(-1), when the CWPO process is performed with [4-NP](o) = 200 mg L-1 at pH = 3, to 1250 mgg(-1) h(-1), when [4-NP](o) = 5 g L-1. High efficiency of H2O2 consumption is obtained when MGNC is applied in the CWPO of 4 -NP solutions at pH = 3, with TOC removals per unit of H2O2 decomposed (n(H2O2)) in the range 64-100%. In addition, the MGNC catalyst is also active at pH = 6; in this case a pollutant mass removal of 2090 mg g(-1) h(-1) was obtained. Although MGNC partially deactivates through successive reusability cycles, the pollutant mass removal obtained at the end of the fourth cycle is still very high when 200 mg L-1 4-NP solutions are considered (4808 mg g(-1) h(-1), representing only a ca. 4% decrease when compared to the first cycle). A higher deactivation of the MGNC catalyst is observed when 5 gL(-1) 4-NP solutions are employed. Nevertheless, the pollutant mass removal obtained at the end of the third cycle is still high (551 mgg(-1) h(-1))

    The NAC domain-containing protein, GmNAC6, is a downstream component of the ER stress- and osmotic stress-induced NRP-mediated cell-death signaling pathway

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    <p>Abstract</p> <p>Background</p> <p>The endoplasmic reticulum (ER) is a major signaling organelle, which integrates a variety of responses against physiological stresses. In plants, one such stress-integrating response is the N-rich protein (NRP)-mediated cell death signaling pathway, which is synergistically activated by combined ER stress and osmotic stress signals. Despite the potential of this integrated signaling to protect plant cells against different stress conditions, mechanistic knowledge of the pathway is lacking, and downstream components have yet to be identified.</p> <p>Results</p> <p>In the present investigation, we discovered an NAC domain-containing protein from soybean, GmNAC6 (<it>Glycine max </it>NAC6), to be a downstream component of the integrated pathway. Similar to <it>NRP-A </it>and <it>NRP-B, GmNAC6 </it>is induced by ER stress and osmotic stress individually, but requires both signals for full activation. Transient expression of <it>GmNAC6 </it>promoted cell death and hypersensitive-like responses <it>in planta</it>. <it>GmNAC6 </it>and <it>NRPs </it>also share overlapping responses to biotic signals, but the induction of <it>NRPs </it>peaked before the increased accumulation of GmNAC6 transcripts. Consistent with the delayed kinetics of <it>GmNAC6 </it>induction, increased levels of <it>NRP-A </it>and <it>NRP-B </it>transcripts induced promoter activation and the expression of the <it>GmNAC6 </it>gene.</p> <p>Conclusions</p> <p>Collectively, our results biochemically link GmNAC6 to the ER stress- and osmotic stress-integrating cell death response and show that GmNAC6 may act downstream of the NRPs.</p

    Cost-Effectiveness of Haemorrhoidal Artery Ligation versus Rubber Band Ligation for the Treatment of Grade II–III Haemorrhoids: Analysis Using Evidence from the HubBLe Trial

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    Aim Haemorrhoids are a common condition, with nearly 30,000 procedures carried out in England in 2014/15, and result in a significant quality-of-life burden to patients and a financial burden to the healthcare system. This study examined the cost effectiveness of haemorrhoidal artery ligation (HAL) compared with rubber band ligation (RBL) in the treatment of grade II–III haemorrhoids. Method This analyses used data from the HubBLe study, a multicentre, open-label, parallel group, randomised controlled trial conducted in 17 acute UK hospitals between September 2012 and August 2015. A full economic evaluation, including long-term cost effectiveness, was conducted from the UK National Health Service (NHS) perspective. Main outcomes included healthcare costs, quality-adjusted life-years (QALYs) and recurrence. Costeffectiveness results were presented in terms of incremental cost per QALY gained and cost per recurrence avoided. Extrapolation analysis for 3 years beyond the trial follow-up, two subgroup analyses (by grade of haemorrhoids and recurrence following RBL at baseline), and various sensitivity analyses were undertaken. Results In the primary base-case within-trial analysis, the incremental total mean cost per patient for HAL compared with RBL was £1027 (95% confidence interval [CI] £782– £1272, p\0.001). The incremental QALYs were 0.01 QALYs (95% CI -0.02 to 0.04, p = 0.49). This generated an incremental cost-effectiveness ratio (ICER) of £104,427 per QALY. In the extrapolation analysis, the estimated probabilistic ICER was £21,798 per QALY. Results from all subgroup and sensitivity analyses did not materially change the base-case result. Conclusions Under all assessed scenarios, the HAL procedure was not cost effective compared with RBL for the treatment of grade II-III haemorrhoids at a cost-effectiveness threshold of £20,000 per QALY; therefore

    Fast polarization mechanisms in the uniaxial tungsten-bronze relaxor strontium barium niobate SBN-81

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    The high-frequency dielectric response of the uniaxial strontium barium niobate crystals with 81% of Sr has been studied from 1 kHz to 30 THz along the polar c axis by means of several techniques (far infrared, time domain terahertz, high-frequency and low-frequency dielectric spectroscopies) in a wide temperature interval 20–600 K. Relaxor properties were observed in the complex dielectric response and four main excitations were ascertained below the phonon frequencies. These fast polarization mechanisms take place at THz, GHz and MHz ranges and show different temperature evolution. The central mode excitation in the THz range, related to anharmonic dynamics of cations, slightly softens from high temperatures and then hardens below T ~ 400 K. Below the phase transition (at T ~ 330 K) an additional microwave excitation appears near 10 GHz related to micro domain wall oscillations. The strongest relaxation appears in the GHz range and slows down on cooling according to the Arrhenius law. Finally, another relaxation, present in the MHz range at high temperatures, also slows down on cooling at least to the kHz range. These two relaxations are due to polar fluctuations and nanodomains dynamics. Altogether, the four excitations explain the dielectric permittivity maximum in the kHz range

    Validación del Nursing Activities Score en unidades de cuidados intensivos portuguesas

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    Objective: to describe the process of adaptation and validation of the Nursing Activities Score to the Portuguese context. Method: this was a pilot study of adaptation and validation of the Nursing Activities Score with a sample consisting of 67 patients hospitalized in the intensive care units of three Portuguese hospitals. The construct validity was assessed through factor analysis procedures and the internal consistency of the items was measured through the Cronbach’s alpha coeffi cient. Results: a mean workload value of 63.04% (SD = 14.25; Median = 61.30) was obtained. Psychometric data revealed a Cronbach’s alpha of 0.71 in the total scale, indicating an acceptable accuracy. Confi rmatory factor analysis suggested an appropriate adjustment between the model and the data (χ2 (199) = 214.5, p = 0.214; CFI = 0.95; RMSA = 0.035). Conclusion: in the present study, the Portuguese version of the Nursing Activities Score was found to be a valid instrument, enabling a safe assessment of the workload of nurses.Objetivo: descrever o processo de adaptação e validação do Nursing Activities Score para o contexto português. Método: trata-se de um estudo-piloto de adaptação e validação do Nursing Activities Score, com amostra de 67 doentes internados em unidades de cuidados intensivos de três hospitais portugueses. A validade de constructo avaliou-se mediante procedimentos de análise fatorial e a consistência interna dos itens através do coefi ciente Alpha de Cronbach. Resultados: obteve-se um valor médio da carga de trabalho de 63,04% (DP = 14,25; Mediana = 61,30). Os dados psicométricos revelaram um Alpha de Cronbach de 0,71, na escala total, indicando uma fi delidade aceitável. A análise fatorial confi rmatória sugeriu um ajustamento adequado entre o modelo e os dados (χ2(199) = 214,5, p = 0,214; CFI = 0,95; RMSA = 0,035). Conclusão: neste estudo, a versão portuguesa do Nursing Activities Score revelou-se um instrumento válido, permitindo avaliar a carga de trabalho dos enfermeiros com segurançaObjetivo: describir el proceso de adaptación y validación del Nursing Activities Score al contexto portugués. Método: estudio piloto de adaptación y validación del Nursing Activities Score, con muestra de 67 pacientes internados en unidades de cuidados intensivos de tres hospitales portugueses. La validez del constructo se evaluó mediante análisis factorial y por consistencia interna de los ítems evaluados a través del coefi ciente Alpha de Cronbach. Resultados: se obtuvo un valor medio de carga de trabajo de 63,04% (SD=14,25; Mediana=61,30). Los datos psicométricos expresaron un Alpha de Cronbach de 0,71 en la escala total, indicando fi delidad aceptable. El análisis factorial confi rmatorio sugirió un ajuste adecuado entre el modelo y os datos (χ2 (199)=214,5; p=0,214; CFI=0,95; RMSA=0,035). Conclusión: en este estudio, la versión portuguesa del Nursing Activities Score demostró ser un instrumento válido, permitiendo evaluar la carga de trabajo de los enfermeros con precisión

    Assessment of angiogenesis by CD105 antigen in epithelial salivary gland neoplasms with diverse metastatic behavior

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    <p>Abstract</p> <p>Background</p> <p>Information on the biology of metastasis development in salivary gland tumors is scarce. Since angiogenesis seems associated with this phenomenon in other tumors, we sought to compare salivary gland tumors with diverse metastatic behavior in order to improve the knowledge and management of these lesions.</p> <p>Methods</p> <p>Samples from the most important salivary gland tumors were segregated according to its metastatic behavior and submitted to routine immunohistochemistry to identify vessels positive for CD105 expression. Frequency of positive cases and intratumoral microvessel density (IMD) was compared among the group of lesions.</p> <p>Results</p> <p>CD105 positive vessels were absent in normal salivary gland tissue, were rare in pleomorphic adenomas and adenoid cystic carcinomas (ACC), more common in polymorphous low-grade adenocarcinomas and highest in mucoepidermoid carcinomas. Only ACC with such feature were metastatic. IMD was higher in malignant rather than benign tumors.</p> <p>Conclusion</p> <p>Immunostaining of CD105 in salivary gland tumors implies participation of angiogenesis in the development of malignant lesions, as well as some role for myoepithelial cells in the control of new vessel formation. In addition, suggest that ACC with positive CD105 vessels are at higher risk for metastasis.</p
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