Showing papers by "National Nuclear Energy Commission published in 2012"
TL;DR: Antifungal PDT is an area of increasing interest, as research is advancing to identify the photochemical and photophysical mechanisms involved in photoinactivation, to develop potent and clinically compatible photosensitizers, and to understand how photoin activation is affected by key microbial phenotypic elements multidrug resistance and efflux, virulence and pathogenesis determinants, and formation of biofilms.
Abstract: Opportunistic fungal pathogens may cause superficial or serious invasive infections, especially in immunocompromised and debilitated patients. Invasive mycoses represent an exponentially growing threat for human health due to a combination of slow diagnosis and the existence of relatively few classes of available and effective antifungal drugs. Therefore systemic fungal infections result in high attributable mortality. There is an urgent need to pursue and deploy novel and effective alternative antifungal countermeasures. Photodynamic therapy (PDT) was established as a successful modality for malignancies and age-related macular degeneration but photodynamic inactivation has only recently been intensively investigated as an alternative antimicrobial discovery and development platform. The concept of photodynamic inactivation requires microbial exposure to either exogenous or endogenous photosensitizer molecules, followed by visible light energy, typically wavelengths in the red/near infrared region that cause the excitation of the photosensitizers resulting in the production of singlet oxygen and other reactive oxygen species that react with intracellular components, and consequently produce cell inactivation and death. Antifungal PDT is an area of increasing interest, as research is advancing (i) to identify the photochemical and photophysical mechanisms involved in photoinactivation; (ii) to develop potent and clinically compatible photosensitizers; (iii) to understand how photoinactivation is affected by key microbial phenotypic elements multidrug resistance and efflux, virulence and pathogenesis determinants, and formation of biofilms; (iv) to explore novel photosensitizer delivery platforms; and (v) to identify photoinactivation applications beyond the clinical setting such as environmental disinfectants.
228 citations
TL;DR: In this article, the authors used the Monte Carlo method to calculate the photon detection efficiency and energy resolution curves for a 1.5″ × 1.1″ NaI(Tl) scintillator detector (crystal+housing+photomultiplier tube material equivalent) exposed to gamma rays in the energy range from 20-kV to 662kV.
111 citations
University of Leeds1, National Nuclear Energy Commission2, National Oceanic and Atmospheric Administration3, National Institute for Space Research4, University of São Paulo5, Woods Hole Research Center6, Environmental Change Institute7, University of Exeter8, Duke University9, University of Sheffield10, Max Planck Society11, James Cook University12
TL;DR: In this paper, the contemporary carbon budget of South America and relate it to its dominant controls: popu- lation and economic growth, changes in land use practices and a changing atmospheric environment and climate.
Abstract: We summarise the contemporary carbon budget of South America and relate it to its dominant controls: popu- lation and economic growth, changes in land use practices and a changing atmospheric environment and climate. Com- ponent flux estimate methods we consider sufficiently reli- able for this purpose encompass fossil fuel emission invento- ries, biometric analysis of old-growth rainforests, estimation of carbon release associated with deforestation based on re- mote sensing and inventories, and agricultural export data. Alternative methods for the estimation of the continental- scale net land to atmosphere CO2 flux, such as atmospheric transport inverse modelling and terrestrial biosphere model
80 citations
TL;DR: Significant reduction on NRRT results was found at 12 ng L(-1), demonstrating the current risk of the continuous introduction of Triclosan into aquatic environments, and the need of ecotoxicological studies oriented by the mechanism of action of the compound.
77 citations
TL;DR: In the in vivo study, aPDT was able to reduce bacterial load in burn wounds, delay bacteremia and keep the bacterial levels in blood 2–3 logs lower compared with an untreated group, suggesting that a PDT may also be a novel prophylactic treatment in the care of burned patients.
Abstract: Pseudomonas aeruginosa is considered one of the most important pathogens that represent life-threatening risk in nosocomial environments, mainly in patients with severe burns. Antimicrobial photodynamic therapy (aPDT) has been effective to kill bacteria. The purpose of this study was to develop a burn wound and bloodstream infection model and verify aPDT effects on it. In vitro, we tested two wavelengths (blue and red LEDs) on a clinical isolate of P. aeruginosa strain with resistance to multiple
70 citations
TL;DR: It is suggested that aPDT is a potential approach to oral candidiasis treatment in HIV-infected patients and it did not prevent the return of the candidiasis in short-term.
Abstract: Objective: Antimicrobial photodynamic therapy (aPDT) has been used to combat local infections, and it consists of the combination of a photosensitizer, a light source, and reactive oxygen species (ROS) to kill microbial cells. In this study, we evaluated the effectiveness of aPDT in the treatment of candidiasis in HIV-infected patients. Methods: Twenty-one patients were divided into three groups. Control group (CG) was treated with the conventional medication for candidiasis (fluconazole 100 mg/day during 14 days). Laser group (LG) was subjected to low-level laser therapy (LLLT), wavelength 660 nm, power of 30 mW, and fluence of 7.5 J/cm2, in contact with mucosa during 10 sec on the affected point. An aPDT group (aPDTG) was treated with aPDT, that is, combination of a low-power laser and methylene blue 450 μg/mL. Pre-irradiation time was 1 min. Parameters of irradiation were the same ones as for the LG, and patients were single irradiated. Patients were clinically evaluated and culture analysis w...
70 citations
TL;DR: No evidence was found of any effect of LLLT on the stability of the implants when measured by RFA, suggesting high primary stability and good bone quality are of major relevancy for a rigid bone–implant interface, and additional L LLT may have little impact macroscopically.
Abstract: Little is known about the benefits of low-level laser therapy (LLLT) on improvement of stability of dental implants. The aim of this randomized clinical study was to assess the LLLT effect on implants stability by means of resonance frequency analysis (RFA). Thirty implants were distributed bilaterally in the posterior mandible of eight patients. At the experimental side, the implants were submitted to LLLT (830 nm, 86 mW, 92.1 J/cm2, 0.25 J, 3 s/point, at 20 points), and on the control side, the irradiation was simulated (placebo). The first irradiation was performed in the immediate postoperative period, and it was repeated every 48 h in the first 14 days. The initial implant stability quotient (ISQ) of the implants was measured by means of RFA. New ISQ measurements were made after 10 days, 3, 6, 9, and 12 weeks. The initial ISQ values ranged from 65–84, with a mean of 76, undergoing a significant drop in stability from the 10th day to the 6th week in the irradiated group, and presenting a gradual increase from the 6th to the 12th week. The highest ISQ values were observed on the 10th day in the irradiated group, and the lowest in the 6th week in both groups. Under the conditions of this study, no evidence was found of any effect of LLLT on the stability of the implants when measured by RFA. Since high primary stability and good bone quality are of major relevancy for a rigid bone–implant interface, additional LLLT may have little impact macroscopically.
64 citations
TL;DR: In this article, two small scale trigeneration plants have been tested for overall efficiency evaluation and operational comparison, and the results were presented along with relevant system operational parameters for appropriate operation including natural gas consumption, net electrical and thermal power production, i.e., hot and cold water production rates, primary energy saving index and the energy utilization factor over total and partial electrical load operational conditions.
56 citations
TL;DR: The factors that make BS inconclusive do not affect 18F-fluoride PET/CT which shows a high sensitivity and negative predictive value for excluding bone metastases even in patients with inconclusive conventional BS.
Abstract: Purpose
Bone scintigraphy (BS) has been used extensively for many years for the diagnosis of bone metastases despite its low specificity and significant rate of equivocal lesions. 18F-Fluoride PET/CT has been proven to have a high sensitivity and specificity in the detection of malignant bone lesions, but its effectiveness in patients with inconclusive lesions on BS is not well documented. This study evaluated the ability of 18F-fluoride PET/CT to exclude bone metastases in patients with various malignant primary tumours and nonspecific findings on BS.
56 citations
TL;DR: This integrated approach using transplanted mussels showed satisfactory results, pointing out differences between sites, seasons, and critical areas, which could be related to land‐based contaminants' sources.
Abstract: This study aimed to provide the first biomonitoring integrating biomarkers and bioaccumulation data in Sao Paulo coast, Brazil and, for this purpose, a battery of biomarkers of defense mechanisms was analyzed and linked to contaminants' body burden in a weigh-of-evidence approach. The brown mussel Perna perna was selected to be transplanted from a farming area (Caraguatatuba) to four possibly polluted sites: Engenho D'Agua, DTCS (Dutos e Terminais do Centro-Oeste de Sao Paulo) oil terminal (Sao Sebastiao zone), Palmas Island, and Itaipu (It; Santos Bay zone). After 3 months of exposure in each season, mussels were recollected and the cytochrome P4501A (CYP1A)- and CYP3A-like activities, glutathione-S-transferase and antioxidants enzymes (catalase, glutathione peroxidase, and glutathione reductase) were analyzed in gills. The concentrations of polycyclic aromatic hydrocarbons, linear alkylbenzenes, and nonessential metals (Cr, Cd, Pb, and Hg) in whole tissue were also analyzed and data were linked to biomarkers' responses by multivariate analysis (principal component analysis—factor analysis). A representation of estimated factor scores was performed to confirm the factor descriptions and to characterize the studied stations. Biomarkers exhibited most significant alterations all year long in mussels transplanted to It, located at Santos Bay zone, where bioaccumulation of organic and inorganic compounds was detected. This integrated approach using transplanted mussels showed satisfactory results, pointing out differences between sites, seasons, and critical areas, which could be related to land-based contaminants' sources. The influence of natural factors and other contaminants (e.g., pharmaceuticals) on biomarkers' responses are also discussed. © 2010 Wiley Periodicals, Inc. Environ Toxicol, 2012.
49 citations
TL;DR: In this article, the authors compare the consistent histories approach with the de Broglie-Bohm theory when applied to this simple model under two different quantization schemes: the Schr\"odinger-like quantization, which essentially takes the square root of the resulting Klein-Gordon equation through the restriction to positive frequencies and their associated Newton-Wigner states, or the induced Klein Gordon quantization that allows both positive and negative frequencies together.
Abstract: We study the Wheeler-DeWitt quantum cosmology of a spatially flat Friedmann cosmological model with a free massless scalar field. We compare the consistent histories approach with the de Broglie--Bohm theory when applied to this simple model under two different quantization schemes: the Schr\"odinger-like quantization, which essentially takes the square root of the resulting Klein-Gordon equation through the restriction to positive frequencies and their associated Newton-Wigner states, or the induced Klein-Gordon quantization, that allows both positive and negative frequencies together. We show that the consistent histories approach can give a precise answer to the question concerning the existence of a quantum bounce if and only if one takes the single frequency approach within a single family of histories; namely, a family containing histories concerning properties of the quantum system at only two specific moments of time: the infinity past and the infinity future. In that case, as shown by Craig and Singh [Phys. Rev. D 82, 123526 (2010)], there is no quantum bounce. In any other situation, the question concerning the existence of a quantum bounce has no meaning in the consistent histories approach. On the contrary, we show that if one considers the de Broglie--Bohm theory, there are always states where quantum bounces occur in both quantization schemes. Hence, the assertion that the Wheeler-DeWitt quantization does not solve the singularity problem in cosmology is not precise. To address this question, one must specify not only the quantum interpretation adopted but also the quantization scheme chosen.
TL;DR: In this article, the results of a finite element simulation of the quenching of an AISI 4140 steel C-ring in oil are presented, covering the analysis of the distortion caused by both thermal contraction and phase transformation, as well as the hardness and martensite volume fractions.
TL;DR: In this article, a new measurement of the 11B(p,?0)8Be has been performed applying the Trojan horse method (THM) to the 2H(11B,?80Be)n quasi-free reaction induced at a laboratory energy of 27 MeV.
Abstract: A new measurement of the 11B(p,?0)8Be has been performed applying the Trojan horse method (THM) to the 2H(11B,?80Be)n quasi-free reaction induced at a laboratory energy of 27 MeV. The astrophysical S(E) factor has been extracted from ?600 keV down to zero energy by means of an improved data analysis technique and it has been compared with direct data available in the literature. The range investigated here overlaps with the energy region of the light element LiBeB stellar burning and with that of future aneutronic fusion power plants using the 11B+p fuel cycle. The new investigation described here confirms the preliminary results obtained in the recent TH works. The origin of the discrepancy between the direct estimate of the 11B(p,?0)8Be S(E)-factor at zero energy and that from a previous THM investigation is quantitatively corroborated. The results obtained here support, within the experimental uncertainties, the low-energy S(E)-factor extrapolation and the value of the electron screening potential deduced from direct measurements.
TL;DR: Complexes (3), (5) and (6) displayed the best IC(90) and IC(50) in the presence of the fungi, greater than that of miconazole, used as control drug and the results correlated well with a performed study of structure-activity relationship (SAR).
TL;DR: The validation of the Diagonal Scan (D-Scan) technique to determine the incubation parameter for ultrashort laser pulses ablation shows good agreement.
Abstract: We report the validation of the Diagonal Scan (D-Scan) technique to determine the incubation parameter for ultrashort laser pulses ablation. A theory to calculate the laser pulses superposition and a procedure for quantifying incubation effects are described, and the results obtained for BK7 samples in the 100 fs regime are compared to the ones given by the traditional method, showing a good agreement.
TL;DR: An electrolyte supported solid oxide fuel cell (SOFC) using standard electrodes, doped-lanthanum manganite cathode and Ni-cermet anode, was operated with direct (anhydrous) ethanol for more than 100h, delivering essentially the same power output as running on hydrogen as mentioned in this paper.
TL;DR: In Latin America and the Caribbean and particularly in Brazil there are 24 and 16 industrial electron beam accelerators (EBA) respectively with energy from 200-keV to 10-meV, operating in private companies and governmental institutions to enhance the physical and chemical properties of materials as mentioned in this paper.
TL;DR: In this article, the transport and catalytic properties of LSCM were studied in compounds with partial substitutions of either Mn or Cr by Ru (LSCM-Ru).
TL;DR: In this paper, the synthesis and characterization of maghemite nanoparticles obtained by a new synthetic route is described, where triethylamine is used as a coprecipitation agent in the presence of the organic ligand N, N′ -bis(3,5-di-tert-butyl-catechol)-2,4-diaminotoluene (LCH 3 ).
TL;DR: The findings from the research illustrate how partial crystallization and phase transformations modified the microstructure of the based glassy material, resulting in improved mechanical properties, providing support for implant materials based on the 3CaO.
Abstract: The aim of this study is to report on the development and characterization of bioactive glass and glass-ceramics from the 3CaO.P 2 O 5 -SiO 2 -MgO-system, using different degrees of cristallinity for applications as an implant material. A methodology was proposed to induce crystallization of phases. Bioglass samples of the nominal composition (wt %) 57.75 CaO.P 2 O 5 –30 SiO 2 –17.25 MgO were heat treated at temperatures ranging from 700 to 1100 °C for 4 h. The findings from the research illustrate how partial crystallization and phase transformations modified the microstructure of the based glassy material, resulting in improved mechanical properties. The maximum gain was measured for samples treated at 975 °C, having a hardness of 6.2 GPa, an indentation fracture toughness of 1.7 MPam 1/2 and a bending strength of 120 MPa, representing an increase of 30, 55 and 70%, respectively, when compared to the nucleated glass. The highest elastic modulus of about 130 GPa was determined for samples treated at 1100 °C. As a preliminary biological evaluation, “in vitro” cytotoxicity tests were realized to determine the cytotoxic level of the materials, using the neutral red uptake method with NCTC clones L929 from the American Type Culture Collection (ATCC) bank. On the other hand, no significant influence of the partial crystallization on cytotoxicity was observed. The results provide support for implant materials based on the 3CaO.P 2 O 5 -SiO 2 -MgO-system.
TL;DR: The objective of this study was to determine the absorption coefficient, penetration depth and effective transmission in materials commonly used in cell cultures and to present a simple equation for estimating the amount of energy that will actually reach the sample.
Abstract: The results of many investigations on low-level laser therapy are contradictory and this is due to the large number of illumination parameters as well as the inability to measure the possible effects after irradiation with the necessary objectivity and the fact that the light needs to pass thorough barriers (usually the plastic of the culture dish/plate and culture medium) to reach the cells. In this manner, the objective of this study was to determine the absorption coefficient, penetration depth and effective transmission in materials commonly used in cell cultures. Among the most commonly used wavelengths in low-level laser therapy, the lowest absorption coefficients were reached by DMEM and RPMI (α = 0.03 cm(-1)), from 633 to 690 nm, which reach an effective transmission of 93% of incident radiation and penetration depth of 33 cm. Among the solid materials in the same range of the electromagnetic spectrum, the lowest absorption coefficient was obtained for the polystyrene (Petri dish and well plate), with α = 1.31 cm(-1), 78% of effective transmission and 0.76 cm of penetration depth. This article also presents a simple equation for estimating the amount of energy that will actually reach the sample.
TL;DR: In this article, the authors combine all the known experimental demonstrations and spectroscopic parameters into a numerical model of the Ho3+-doped fluoride glass fiber laser system, and find that the best match with measurements required scaleddown rate parameters for the energy transfer processes that operate in moderate to highly concentrated systems.
Abstract: We combine all the known experimental demonstrations and spectroscopic parameters into a numerical model of the Ho3+-doped fluoride glass fiber laser system. Core-pumped and cladding-pumped arrangements were simulated for all the population-bottlenecking mitigation schemes that have been tested, and good agreement between the model and the previously reported experimental results was achieved in most but not in all cases. In a similar way to Er3+-doped fluoride glass fiber lasers, we found that the best match with measurements required scaled-down rate parameters for the energy transfer processes that operate in moderate to highly concentrated systems. The model isolated the dominant processes affecting the performance of each of the bottlenecking mitigation schemes and pump arrangements. It was established that pump excited-state absorption is the main factor affecting the performance of the core-pumped demonstrations of the laser, while energy transfer between rare earth ions is the main factor controlling the performance in cladding-pumped systems.
TL;DR: In this paper, the synthesis and catalytic applications of magnetic composites based on carbon nanotubes and nanofibers prepared by CVD (chemical vapor deposition) using two natural materials with special morphology, i.e. layered vermiculite clay and fibrous chrysotile.
TL;DR: Findings suggest that aPDT was competent to reduce cariogenic bacteria and to avoid further mineral loss.
Abstract: In this study we developed a rat model of incipient caries to investigate the short-term effects of antimicrobial photodynamic therapy (aPDT) on oral microbiota regulation and demineralization arrestment. Twenty-nine male rats were submitted to caries induction. Early carious lesion was confirmed by optical coherence tomography (OCT) 5 days after experiment beginning in five animals. The remaining animals (n = 24) were randomly divided into two groups: control (n = 12), animals were untreated; and aPDT (n = 12), animals were treated with 100 μM of methylene blue for 5 min and irradiated by a light emitting diode at λ = 645 ± 30 nm, fluence rate of 480 mW cm(-2) and exposure time of 3 min. Bacterial burden was evaluated before, immediately after, 3, 7 and 10 days following treatment, and total number of microaerophilic bacteria was counted. OCT was also used to quantify teeth demineralization. A significant bacterial decrease of about 1.6 log was observed immediately after aPDT. Besides, bacterial load in aPDT group remained lower than control until 10 days post-treatment (P < 0.05) and variation of optical attenuation coefficient before and after aPDT was 15%, corroborating to caries arrestment. Put together, these findings suggest that aPDT was competent to reduce cariogenic bacteria and to avoid further mineral loss.
TL;DR: In this paper, aqueous polymeric solutions were prepared using two distinct processes: the simple process of heating-stirring and that of making use of an autoclave.
TL;DR: Although the fruit incorporates a lot more potassium than cesium, both radionuclides present similar absorption patterns during the entire growth period, and maximum F(v) values are reached at the initial time of fruit growth and decrease as the fruit develops, being lowest at the maturation period.
TL;DR: The artificial and natural activities determined in this study were found to be below the maximum permissible levels as established by national legislation, and these mushroom species can be normally consumed by the population without any apparent risks to human health.
TL;DR: In this paper, the authors employed this kind of test in Brazilian coastal estuaries to evaluate total mercury and polycyclic aromatic hydrocarbon contamination in sediments and oysters (native and caged Crassostrea rhizophorae).
Abstract: Nowadays, organisms are increasingly being used in biomonitoring to assess bioavailability and bioaccumulation of contaminants. This approach can use both native and transplanted organisms in order to accomplish this task. In Brazil, most of the studies related to bioaccumulation of contaminants in oysters deal with metals. The present work employs this kind of test in Brazilian coastal estuaries (Santos and Paranagua) to evaluate total mercury and polycyclic aromatic hydrocarbon contamination in sediments and oysters (native and caged Crassostrea rhizophorae). The methodologies employed were based on known USEPA methods. Results have shown a significant contamination in Santos sediments and consequent bioavailability of organisms. Paranagua sediments presented lower contamination in sediments, but native oysters were able to accumulate total Hg. The experiments done with caged oysters did not show significant bioaccumulation of Hg and PAHs in the Paranagua site, but proved to be an excellent tool to assess bioavailability in the Santos estuary since they were able to bioaccumulate up to 1,600% of total PAH in the samples from the inner part of this estuary when compared to control organisms. Multivariate statistical analyses employed to these results have separated the sites evaluated and the most contaminated samples from the least contaminated.
TL;DR: The use of microbial cellulolytic enzymes is the most efficient process to liberate glucose from cellulose in biomass without the formation of fermentation inhibitors as discussed by the authors, and a combination of pretreatment technologies is an alternative way to increase the access of enzymes to cellulose, and consequently, the conversion yield.
TL;DR: In this article, a composite consisting of autoclaved cellular concrete (ACC) impregnated with Fe(III) ions was prepared and evaluated as a heterogeneous catalyst for the degradation of the textile dye Indigo Carmine in aqueous medium.