Synthesis and characterization of silver/alanine nanocomposites for radiation detection in medical applications: the influence of particle size on the detection properties

Silver/alanine nanocomposites with varying mass percentage of silver have been produced. The size of the silver nanoparticles seems to drive the formation of the nanocomposite, yielding a homogeneous dispersion of the silver nanoparticles in the alanine matrix or flocs of silver nanoparticles segregated from the alanine crystals. The alanine crystalline orientation is modified according to the particle size of the silver nanoparticles. Concerning a mass percentage of silver below 0.1%, the nanocomposites are homogeneous, and there is no particle aggregation. As the mass percentage of silver is increased, the system becomes unstable, and there is particle flocculation with subsequent segregation of the alanine crystals. The nanocomposites have been analyzed by transmission electron microscopy (TEM), UV-Vis absorption spectroscopy, X-ray diffraction (XRD), and Fourier transform infrared (FTIR) spectroscopy and they have been tested as radiation detectors by means of electron spin resonance (ESR) spectroscopy in order to detect the paramagnetic centers created by the radiation. In fact, the sensitivity of the radiation detectors is optimized in the case of systems containing small particles (30 nm) that are well dispersed in the alanine matrix. As the agglomeration increases, particle growth (up to 1.5 mu m) and segregation diminish the sensitivity. In conclusion, nanostructured materials can be used for optimization of alanine sensitivity, by taking into account the influence of the particles size of the silver nanoparticles on the detection properties of the alanine radiation detectors, thus contributing to the construction of small-sized detectors.

Spectroscopic investigation and heat generation of Yb3+/Ho3+ codoped aluminosilicate glasses looking for the emission at 2 μm

Energy transfer (ET) and heat generation processes in Yb3+/Ho3+-codoped low-silica calcium aluminosilicate glasses were investigated using thermal lens (TL) and photoluminescence measurements looking for the emission around 2.0 μm. Stepwise ET processes from Yb3+ to Ho3+, upon excitation at 0.976 μm, produced highly efficient emission in the mid-infrared range at around 2.0 μm, with high fluorescence quantum efficiency (η1 ∼ 0.85 and independent of Ho3+ concentration) and relatively very low thermal loading (<0.4) for concentration up to 1.5% of Ho2O3. An equation was deduced for the description of the TL results that provided the absolute value of η1 and the number of emitted photons at 2.0 μm per absorbed pump photon by the Yb3+ ions, the latter reaching 60% for the highest Ho3+ concentration. These results suggest that the studied codoped system would be a promising candidate for the construction of photonic devices, especially for medical applications.

Synchrotron X-ray diffraction characterization of healthy and fluorotic human dental enamel

With the introduction of fluoride as the main anticaries agent used in preventive dentistry, and perhaps an increase in fluoride in our food chain, dental fluorosis has become an increasing world-wide problem. Visible signs of fluorosis begin to become obvious on the enamel surface as opacities, implying some porosity in the tissue. The mechanisms that conduct the formation of fluorotic enamel are unknown, but should involve modifications in the basic physical-chemistry reactions of demineralization and remineralisation of the enamel of the teeth, which is the same reaction of formation of the enamel's hydroxyapatite (HAp) in the maturation phase. The increase of the amount of fluoride inside of the apatite will result in gradual increase of the lattice parameters. The aim of this work is to characterize the healthy and fluorotic enamel in human tooth using Synchrotron X-ray diffraction. All the scattering profile measurements were carried out at the X-ray diffraction beamline (XRD1) at the Brazilian Synchrotron Light Laboratory-LNLS, Campinas, Brazil. X-ray diffraction experiments were performed both in powder samples and polished surfaces. The powder samples were analyzed to obtain the characterization of a typical healthy enamel pattern. The polished surfaces were analyzed in specific areas that have been identified as fluorotic ones. X-ray diffraction data were obtained for all samples and these data were compared with the control samples and also with the literature data. (c) 2012 Elsevier Ltd. All rights reserved.

Uso da RMN como um sensor online em processos industriais

Nuclear magnetic resonance (NMR) is one of the most versatile analytical techniques for chemical, biochemical and medical applications. Despite this great success, NMR is seldom used as a tool in industrial applications. The first application of NMR in flowing samples was published in 1951. However, only in the last ten years Flow NMR has gained momentum and new and potential applications have been proposed. In this review we present the historical evolution of flow or online NMR spectroscopy and imaging, and current developments for use in the automation of industrial processes.

Twelve-month clinical outcomes after coronary stenting with the Genous Bio-engineered R Stent in patients with a bifurcation lesion: from the e-HEALING (Healthy Endothelial Accelerated Lining Inhibits Neointimal Growth) registry

Background The e-Healthy Endothelial Accelerated Lining Inhibits Neointimal Growth (e-HEALING) registry was designed to capture clinical data on the use of the endothelial progenitor cell capture stent (ECS) in routine clinical practice. In this analysis, we investigated the 12-month clinical outcomes in patients treated with an ECS for a bifurcation lesion. Methods The worldwide, prospective, nonrandomized e-HEALING registry aimed to enrol 5000 patients treated for coronary artery disease with one or more ECS between October 2005 and October 2007. Clinical follow-up was obtained at 1, 6, and 12 months. The primary endpoint was target vessel failure (TVF), defined as the composite of cardiac death, myocardial infarction, and target vessel revascularization at 12 months. Results A total of 573 patients were treated for at least one bifurcation lesion and were assessed in the current analysis. Baseline characteristics showed a median age of 65 years; 21% were diabetic patients and 36% had unstable angina. A total of 63% of the bifurcation lesions were located in the left artery descending and the mean stent length was 20.7 +/- 12.6 mm. At 12 months, TVF was 12.7% and target lesion revascularization was 7.5%. Definite or probable stent thrombosis occurred in 1.7% of the patients. Moreover, one or more stents per lesion [hazard ratio (HR): 2.79, 95% confidence interval (CI): 1.60-4.86, P < 0.001], predilatation (HR: 0.39, 95% CI: 0.17-0.87, P = 0.023), and lesions located in the right coronary artery (HR: 4.56, 95% CI: 1.07-19.5, P = 0.041) were independent predictors of TVF. Conclusion In the e-HEALING registry, coronary bifurcation stenting with the ECS results in favorable clinical outcomes and low incidences of repeat revascularization and stent thrombosis. Coron Artery Dis 23:201-207 (C) 2012 Wolters Kluwer Health vertical bar Lippincott Williams & Wilkins.

Duration of dual antiplatelet therapy and outcomes after coronary stenting with the genous (TM) bio-engineered R stent (TM) in patients from the e-healing registry

Objective: We investigated the relation between duration of dual antiplatelet therapy (DAPT) and clinical outcomes up to 12 months after Genous (TM) endothelial progenitor cell capturing R stent (TM) placement in patients from the e-HEALING registry. Background: Cessation of (DAPT) has been shown to be associated with the occurrence of stent thrombosis (ST). After Genous placement, 1 month of DAPT is recommended. Methods: Patients were analyzed according to continuation or discontinuation of DAPT at a 30-day and 6-month landmark, excluding patients with events before the landmark. Each landmark was a new baseline, and outcomes were followed up to 12 months after stenting. The main outcome for our current analysis was target vessel failure (TVF), defined as target vessel-related cardiac death or myocardial infarction and target vessel revascularization. Secondary outcomes included ST. (Un)adjusted hazard ratios (HR) for TVF were calculated with Cox regression. Results: No difference was observed in the incidence of TVF [HR: 1.03; 95% confidence intervals (CI): 0.651.65, P = 0.89] in patients continuing DAPT (n = 4,249) at 30 days versus patients stopped (n = 309), and HR: 0.82 (95% CI: 0.551.23, P = 0.34) in patients continuing DAPT (n = 2,654) at 6 months versus patients stopped [n = 1,408] DAPT). Furthermore, no differences were observed in ST. Even after addition of identified independent predictors for TVF, adjusted TVF hazards were comparable. Conclusions: In a post-hoc analysis of e-HEALING, duration of DAPT was not associated with the occurrence of the outcomes TVF or ST. The Genous stent may be an attractive treatment especially in patients at increased risk for (temporary) cessation of DAPT or bleeding. (C) 2011 Wiley Periodicals, Inc.

Progress in animal experimentation ethics. A case study from a brazilian medical school and from the international medical literature

PURPOSE: This study describes in Brazil and in the global biomedical community the time course of the development of animal research welfare guidelines. METHODS: The database of the Ethics Committee of the Faculty of Medicine of Ribeirao Preto (EC/FMRP-USP), Brazil, was surveyed since its inception in 2002 as the regulations became more stringent to provide better protection of animal research welfare at this institution. Medline database was evaluated to identify the number of publications in the period between 1968 and 2008 that used research animals and were in compliance with established ethics guidelines. RESULTS: The EC/FMRP-USP evaluated 979 projects up until 2009. Most of the applications came from Department of Physiology and the most frequently requested species was the rat. In 2004, national research funding agencies started to request prior approval from institutional review ethics committees prior to application review and this requirement became federal law in Brazil in 2008. The analysis of international publications revealed a relative reduction in studies involving research animals (18% in 1968 to 7.5% in 2008). CONCLUSIONS: The present work showed that in the last four decades major changes occurred in the guidelines dictating use of research animals occurred and they are being adopted by developing countries. Moreover, animal welfare concern in the scientific community preceded the introduction of journal guidelines for this purpose. Furthermore, in Brazil it was anticipated that laws were needed to protect animal research welfare from being not upheld.

Cone Beam Computed Tomographic Imaging: Perspective, Challenges, and the Impact of Near-Trend Future Applications

Cone beam computed tomography (CBCT) can be considered as a valuable imaging modality for improving diagnosis and treatment planning to achieve true guidance for several craniofacial surgical interventions. A new concept and perspective in medical informatics is the highlight discussion about the new imaging interactive workflow. The aim of this article was to present, in a short literature review, the usefulness of CBCT technology as an important alternative imaging modality, highlighting current practices and near-term future applications in cutting-edge thought-provoking perspectives for craniofacial surgical assessment. This article explains the state of the art of CBCT improvements, medical workstation, and perspectives of the dedicated unique hardware and software, which can be used from the CBCT source. In conclusion, CBCT technology is developing rapidly, and many advances are on the horizon. Further progress in medical workstations, engineering capabilities, and improvement in independent software-some open source-should be attempted with this new imaging method. The perspectives, challenges, and pitfalls in CBCT will be delineated and evaluated along with the technological developments.

NUTRITIONAL BALANCE, ESSENTIAL OIL AND WOOD PRODUCTION FROM Corymbia citriodora Hill & Johnson WITH SEWAGE SLUDGE AND MINERAL FERTILIZER APPLICATIONS

The Corymbia citriodora is one of the most important forest species in Brazil and the reason is the diversity of its use, because it produces good quality wood and the leaves may be used for essential oil production. Although, there are not many studies about species and the handling effect in the nutritional balance. This study aimed to evaluate the biomass production and nutrient balance in the conventional production of essential oil and wood of Corymbia citriodora with sewage sludge application. The experiment design established was the randomized blocks, with four replicates and two treatments: 1 - fertilization with 10 tons ha(-1) (dry mass) of sewage sludge, supplemented with K and B, and 2 - mineral fertilization. It was evaluated the aerial biomass production, the nutrient export of the leaves, the essential oil and wood production at four years old. The trees that received application of sewage sludge produced 20 % more leaves biomass than the trees with mineral fertilization, resulting in larger oil production. Besides, the trees with sewage sludge application produced 14.2 tons ha(-1) yr(-1) of woody biomass that was 27 % higher than the treatment with mineral fertilization. For both treatments the N balance was negative, but treatment with sewage sludge application (-45 kg ha(-1)) was four times lower than the observed on mineral fertilization treatment (-185 kg ha(-1)). It may be concluded in this paper that the application of sewage sludge benefits the production of leaves biomass, essential oil and wood, besides result better nutritional balance of the Corymbia citriodora production system.

Synthesis of silver nanoparticles using DL-alanine for ESR dosimetry applications

The potential use of alanine for the production of nanoparticles is presented here for the first time. Silver nanoparticles were synthesized using a simple green method, namely the thermal treatment of silver nitrate aqueous solutions with in-alanine. The latter compound was employed both as a reducing and a capping agent. Particles with average size equal to 7.5 nm, face-centered cubic crystalline structure, narrow size distribution, and spherical shape were obtained. Interaction between the silver ions present on the surface of the nanoparticles and the amine group of the DL-alanine molecule seems to be responsible for reduction of the silver ions and for the stability of the colloid. The bio-hybrid nanocomposite was used as an ESR dosimeter. The amount of silver nanoparticles in the nanocomposite was not sufficient to cause considerable loss of tissue equivalency. Moreover, the samples containing nanoparticles presented increased sensitivity and reduced energetic dependence as compared with pure DL-alanine, contributing to the construction of small-sized dosimeters. (C) 2011 Elsevier Ltd. All rights reserved.

Applying the National Institute for Clinical Excellence criteria to patients treated with the Genous (TM) Bio-engineered R stent (TM): a sub-study of the e-HEALING (Healthy Endothelial Accelerated Lining Inhibits Neointimal Growth) worldwide registry

The National Institute for Clinical Excellence (NICE) guidelines recommend the use of bare-metal stents (BMS) in non-complex lesions with a low risk of restenosis (diameter a parts per thousand yen3 mm and lesion length a parts per thousand currency sign15 mm) and the use of drug-eluting stents (DES) in more complex lesions with a high risk of restenosis (diameter < 3.0 mm or lesion length > 15 mm). However, the guidelines were created based on studies evaluating BMS and DES only. We performed an analysis of patients undergoing non-urgent percutaneous coronary intervention with the novel endothelial cell capturing stent (ECS). The ECS is coated with CD34(+) antibodies that attract circulating endothelial progenitor cells to the stent surface, thereby accelerating the endothelialization of the stented area. We analyzed all patients enrolled in the worldwide e-HEALING registry that met the NICE criteria for either low-risk or high-risk lesions and were treated with a parts per thousand yen1 ECS. The main study outcome was target vessel failure (TVF) at 12-month follow-up, defined as the composite of cardiac death or MI and target vessel revascularization (TVR). A total of 4,241 patients were assessed in the current analysis. At 12-month follow-up, TVF occurred in 7.0% of the patients with low-risk lesions and in 8.8% of the patients with high-risk lesions (p = 0.045). When evaluating the diabetic patients versus the non-diabetic patients per risk group, no significant differences were found in TVF, MI or TVR in either risk group. The ECS shows good clinical outcomes in lesions carrying either a high or a low risk of restenosis according to the NICE guidelines with comparable rates of cardiac death, myocardial infarction, and stent thrombosis. The TVF rate with ECS was slightly higher in patients with high-risk lesions, driven by higher clinically driven TLR. The risk of restenosis with ECS in patients carrying high-risk lesions needs to be carefully considered relative to other risks associated with DES. Furthermore, the presence of diabetes mellitus did not influence the incidence of TVF in either risk group.

Progress in animal experimentation ethics: a case study from a Brazilian medical school and from the international medical literature

PURPOSE: This study describes in Brazil and in the global biomedical community the time course of the development of animal research welfare guidelines. METHODS: The database of the Ethics Committee of the Faculty of Medicine of Ribeirao Preto (EC/FMRP-USP), Brazil, was surveyed since its inception in 2002 as the regulations became more stringent to provide better protection of animal research welfare at this institution. Medline database was evaluated to identify the number of publications in the period between 1968 and 2008 that used research animals and were in compliance with established ethics guidelines. RESULTS: The EC/FMRP-USP evaluated 979 projects up until 2009. Most of the applications came from Department of Physiology and the most frequently requested species was the rat. In 2004, national research funding agencies started to request prior approval from institutional review ethics committees prior to application review and this requirement became federal law in Brazil in 2008. The analysis of international publications revealed a relative reduction in studies involving research animals (18% in 1968 to 7.5% in 2008). CONCLUSIONS: The present work showed that in the last four decades major changes occurred in the guidelines dictating use of research animals occurred and they are being adopted by developing countries. Moreover, animal welfare concern in the scientific community preceded the introduction of journal guidelines for this purpose. Furthermore, in Brazil it was anticipated that laws were needed to protect animal research welfare from being not upheld.