A cone-beam optical CT based on a convergent light source - Characterization and optimization.

PURPOSE: Employing a Fresnel lens and a point-like light source to create a convergent light beam for the camera effectively minimizes stray light and enhances image quality in optical computed tomography (OCT), benefiting 3D dosimetry applications. This study outlines the development of an economical cone-beam optical computed scanner for 3D dosimetry. METHODS: Optical performance was assessed by calculating modulation transfer function (MTF) with pattern charts. Stray light was evaluated by imaging a cylinder flask and a square grid with 5 mm diameter holes to determine the stray-to-primary ratio. Reconstruction quality was determined using SIRT-TV and compared with spectrophotometry attenuation coefficients, with the best regularization parameter (λ = 0.01) chosen based on contrast-to-noise ratio (CNR). Dosimetry performance was assessed by determining percentage dose depth (PDD) for a 6MV beam with a 5 × 5 cm2 field using FXO-f gel dosimeter, compared with ionization chamber data. RESULTS: MTF evaluation yielded ≥ 50 % agreement with pattern charts. Stray-to-primary ratio was less than 0.1 or 10 % of the total signal. Reconstruction showed low noise and artifacts, with optimal CNR at λ = 0.01. Attenuation coefficients from optical CT aligned with spectrometer measurements within 1.2 %. PDD calculated with FXO-f gel dosimeter closely matched ionization chamber data (<1.2 % difference), achieving a dose resolution of 0.1 Gy. CONCLUSION: The built and optimization the de optical-CT based on a convergent beam is read to perform the 3D quality assurance in clinical applications.

Assessment of dosimetric sensitivity enhancement of xylenol orange Fricke gel by AuNPs: optical and MR imaging investigation.

Metallic nanoparticles, such as gold (Au, Z = 79) and silver (Ag, Z = 47) nanoparticles (AuNPs and AgNPs, respectively), possess strong surface plasmonic resonance (SPR) and high atomic number, which makes them ideal candidates for enhancing dosimeter sensitivity. In this study, we have inserted different mass percentages (from 0 to 0.015 wt%) of AuNPs into a gelatinous Fricke-xylenol-orange (FXO-f) gel matrix and irradiated it with doses ranging from 2 to 32 Gy, using a source of x-ray of low energy with an effective energy of 42 keV. Optical absorption increased significantly; sensitivity gains of up to 50% were achieved for the FXO-f gel matrix containing 0.011 wt% AuNPs. To elucidate the mechanism underlying this increased sensitivity, we also evaluated FXO-f gel matrixes containing AgNPs. AgNPs insertion into the FXO-f gel matrix did not enhance sensitivity, which suggested that the AgNPs plasmonic absorption band and the FXO-f gel matrix absorption band at 441 nm overlapped, to increase absorption even after the gel matrix was irradiated. To visualize the dose distribution, we recorded optical tomography and acquired 3D reconstruction maps. In addition, we analyzed the dose enhancement factor (DEF) by using magnetic resonance images. AuNPs insertion into the FXO-f gel matrix resulted in a DEF gain of 1.37, associated with the photoelectric effect originating from the increased number of free radicals.

Characterization of novel polydiacetylene gel dosimeter for radiotherapy.

Polymer gel dosimeters are instrumental for clinical and research applications in radiotherapy. These dosimeters possess the unique ability to record dose distribution in three dimensions. A Polymer gel dosimeter is composed of organic molecules in a gel matrix, which upon irradiation polymerize to form a conjugated polymer with optical absorbance proportional to the irradiated dose. Other required characteristics of a radiotherapy clinical dosimeter are soft-tissue equivalency, linear dose-response in a range of clinical treatments, and long term stability for the duration of the analysis. The dosimeter presented in this paper is based on diacetylene bearing fatty acid aggregates embedded in a soft-tissue equivalent gel matrix, Phytagel™, which upon irradiation polymerize to form a blue phase polydiacetylene with a strong optical absorption. Initial characterization showed that PDA-gel irradiated with 160 kV x-ray responded linearly to the irradiated dose, and the calculated diffusion coefficient is [Formula: see text] what is very low. It was also found that the percentage depth dose (PDD) curve of the PDA-gel in a 4 × 4 cm2 field, irradiated with 6 MV x-rays, was with good agreement with the literature. PDA-gel has the potential to detect absorbed dose in a range of clinical radiological irradiation regimes.

Three-dimensional quality assurance of IMRT prostate plans using gel dosimetry.

Intensity modulated radiotherapy (IMRT) is one of the most modern radiation therapy treatment techniques. Although IMRT can deliver high and complex conformational doses to the tumor volume, its implementation requires rigorous quality assurance (QA) procedures that include a dosimetric pre-treatment verification of individual patient planning. This verification usually involves measuring a small volume of absolute dose with an ionization chamber and checking bi-dimensional fluency with an array of detectors. The planning technique has tri-dimensional characteristics, but no tridimensional dosimetry has been established in the clinical routine. One strategy to perform three-dimensional dosimetry is to use polymeric gels associated with magnetic resonance imaging to evaluate dose distribution. Here, we have compared the results of conventional QA procedures involving one- and two-dimensional dosimetry to the results of three-dimensional dosimetry conducted with MAGIC-f gel in 10 cases of prostate cancer IMRT planning. More specifically, we used the gamma index (3%/3mm) to compare the results of three-dimensional dosimetry to the expected dose distributions obtained with the treatment planning system. Except for one IMRT treatment plan, the gel dosimetry results agreed with the conventional quality control and provided an overview of dose distribution in the target volume.

Conteúdo fenólico e atividade antioxidante de diferentes cultivares de ipomoea batatas (l.) lam. obtidas por melhoramento genético para produção industrial de etanol / Phenolic content and antioxidant activity of several varieties of Ipomoea batatas (L.) Lam developed for genetic improvement for industrial production of ethanol

The sweet potato ( Ipomoea batatas (L.) Lam ) is a vegetable native to tropical America, now a prominent crop in all parts of the world. The main purpose of cultivating this plant is to produce roots for human and domestic animal consumption and ethanol production. The preferred part of I. batatas is the roots, so that the shoot is generally discarded or used as animal feed. The aim of this study was to determine the total phenolic content, the chromatographic profile and the antioxidant potential of the leaves of 10 cultivars of I. batatas developed by conventional breeding for the industrial production of ethanol. Ethanol extracts of the leaves of mature plants were assayed for phenolic contents by The Folin-Ciocalteu method, which ranged between 54.72 ± 4.35 and 112.29 ± 3.65 mg TAE/g, for flavonoids by complexation with aluminum chloride (29.15 ± 372 to 97.36 ± 2.13 mg RE/g), for in vitro antioxidant activity by the DPPH FRAP methods and for chelating activity. Additionally, the phenolic compounds were investigated by thin layer chromatography (TLC) and high performance liquid chromatography (HPLC), revealing a complex matrix of compounds comprising various flavonoids and ellagic acid. A high antioxidant potential was found, which was satisfactorily correlated by Pearson correlation with total phenolic and flavonoid contents. The results showed a great potential for adding value to the crop of I. batatas, by combining the current agro-energy practice based on its roots with the exploitation of other organic commodities present in its leaves...

A batata-doce (Ipomoea batatas (L.) Lam.) é um vegetal nativo da América Tropical, com destaque no cenário da agricultura mundial. A principal finalidade do cultivo desta planta concentra-se na obtenção de raízes para alimentação humana, de animais domésticos e produção de etanol. A preferência de consumo de I. batatas concentra-se nas raízes, consequentemente a parte aérea, na maioria das vezes, é descartada ou fornecida como alimento para animais. Este trabalho teve como objetivo determinar o conteúdo fenólico total, o perfil cromatográfico e o potencial antioxidante das folhas de 10 cultivares de I. batatas provenientes de melhoramento genético convencional direcionado para a produção industrial de etanol. Extratos etanólicos das folhas de plantas adultas foram avaliados quanto ao conteúdo fenólico pelo método Folin-Ciocalteu, que variou entre 54,72 ± 4,35 e 112,29 ± 3,65 mg EAT/g, flavonoides por complexação com cloreto de alumínio (29,15 ± 3,72 a 97,36 ± 2,13 mg ER/g), atividade antioxidante in vitro pelos métodos DPPH, FRAP e atividade quelante. Adicionalmente, foram investigados os componentes fenólicos por cromatografia em camada delgada (CCD) e cromatografia líquida de alta eficiência (CLAE), que revelaram matrizes complexas de compostos, constituídas por ácido elágico e vários flavonoides. Constatou-se um elevado potencial antioxidante correlacionado satisfatoriamente pelo coeficiente de Pearson com teor de fenóis e flavonoides totais. Os resultados demonstraram grande potencial de agregação de valor ao cultivo de I. batatas, pela integração das práticas agroenergéticas que utilizam suas raízes, com a obtenção de outros produtos de base orgânica presentes nas folhas desta planta...

A system to measure isomeric state half-lives in the 10 ns to 10 µs range.

The Isomeric State Measurement System (SISMEI) was developed to search for isomeric nuclear states produced by fusion-evaporation reactions. The SISMEI consists of 10 plastic phoswich telescopes, two lead shields, one NaI(Tl) scintillation detector, two Compton suppressed HPGe γ-ray detectors, and a cone with a recoil product catcher. The new system was tested at the 8 UD Pelletron tandem accelerator of the University of São Paulo with the measurement of two known isomeric states: (54)Fe, 10(+) state (E = 6527.1 (11) keV, T(1/2) = 364(7) ns) and the 5/2(+) state of (19)F (E = 197.143 (4) keV, T(1/2) = 89.3 (10) ns). The results indicate that the system is capable of identifying delayed transitions, of measuring isomeric state lifetimes, and of identifying the feeding transitions of the isomeric state through the delayed γ-γ coincidence method. The measured half-life for the 10(+) state was T(1/2) = 365(14) ns and for the 5/2(+) state, 100(36) ns.

Influence of a hypercholesterolemic diet on the collagen composition of the bladder wall extracellular matrix in rats.

PURPOSE: To investigate the effects of hypercholesterolemic diet on the collagen composition of urinary bladder wall. MATERIALS AND METHODS: Forty-five female 4-week-old Wistar rats were divided into three groups: 1) control group fed a normal diet (ND); 2) model of bladder outlet obstruction (BOO) group fed a ND; and 3) group fed a HCD (1.25% cholesterol). Total serum cholesterol, LDL cholesterol and body weight were assessed at baseline. Four weeks later, group 2 underwent a surgical procedure resulting in a partial BOO, while groups 1 and 3 underwent a sham similar surgical procedure. Six weeks later, all animals had their bladders removed; serum cholesterol and LDL cholesterol levels and body weights were measured. Morphological and morphometric analysis was performed by Picrosirius staining and collagen types I and III were identified by immunofluorescence. Statistical analysis was completed and significance was considered when p<0.05. RESULTS: Rats fed an HCD exhibited a significant increase in LDL cholesterol levels (p<0.001) and body weight (p=0.017), when compared to the groups fed a ND during the ten-week study period. Moreover, the HCD induced morphological alterations of the bladder wall collagen, regarding thin collagen fibers and the amounts of type III collagen when compared to the control group (p=0.002 and p=0.016, respectively), resembling the process promoted in the BOO model. CONCLUSIONS: A hyper-cholesterolemic diet in Wistar rats promoted morphological changes of the bladder types of collagen, as well as increases in body weight and LDL cholesterol.

Race and glomerulonephritis in patients with and without hepatosplenic Schistosomiasis mansoni.

BACKGROUND/AIMS: United States investigators have shown evidence of higher susceptibility to focal segmental glomerulosclerosis (FSGS) in blacks than in whites. This association between race and FSGS has not been assessed outside the US. The present study assesses the association between race and type of glomerulonephritis in a sample of Brazilian patients, taking into account the presence of the hepatosplenic form of Schistosomiasis mansoni (HSM). METHODS: Eighty patients with focal segmental glomerulosclerosis (FSGS) were compared to 50 with membranoproliferative glomerulonephritis (MPGN). The association between race (i.e. black versus white) and type of glomerulonephritis was adjusted for age, gender and HSM by logistic regression. RESULTS: Blacks were more likely than whites to have FSGS (as compared to MPGN), both among patients with HSM (odds ratio (OR) = 2.67; 95% confidence interval (CI) = 0.81 - 8.81) and without HSM (OR = 2.19; 95% CI = 0.79 - 6.05). After adjustment for age, gender and HSM, the odds of FSGS remained significantly greater for blacks (OR = 2.49; 95% CI = 1.05 - 5.95). CONCLUSION: The increased likelihood of FSGS in Brazilian blacks is consistent with findings from US patients. The association between race and type of glomerulonephritis was similar between patients with and without HSM. Future investigations should focus on the mediators factors that might explain these findings.

Reduction in diastolic blood pressure and cardiovascular mortality in nondiabetic hypertensive patients. A reanalysis of the HOT study.

OBJECTIVE: To use published Hypertension Optimal Treatment (HOT) Study data to evaluate changes in cardiovascular mortality in nondiabetic hypertensive patients according to the degree of reduction in their diastolic blood pressure. METHODS: In the HOT Study, 18,700 patients from various centers were allocated at random to groups having different objectives of for diastolic blood pressure:

[Association between race and incidence of end-stage renal disease secondary to glomerulonephritis: influence of the histologic type and presence of arterial hypertension]. / Associação entre raça e incidência de doença renal terminal secundária a glomerulonefrite: influência do tipo histológico e da presença de hipertensão arterial.

OBJECTIVE: To assess, retrospectively, the association between race and incidence of end-stage renal disease (ESRD) in patients with glomerulonephritis in a University Hospital of Bahia, Brazil. METHODS: The sample was comprised of 79 patients with focal segmental glomerulosclerosis (FSG), 50 with membranoproliferative glomerulonephritis (MPGN) and 49 with other types of glomerulonephritis (OTGN), followed-up between 1970 and 1996 for at least 6 months. It was not included patients with acute glomerulonephritis, minimal change disease, crescentic glomerulonephritis, connective tissue diseases or patients with serum creatinine level greater than or equal to 4.0 mg/dl. The patients were classified according to race as caucasian (white), mulatto or negro. For patients older than 18 yr, not taking antihypertensives drugs, hypertension was defined as a mean of three blood pressure measurements greater than or equal to 140 mmHg for systolic or 90 mmHg for diastolic; for ages

Associaçäo entre raça e incidência de doença renal terminal secundária a glomerulonefrite: influência do tipo histológico e da presença de hipertensäo arterial / Association between race and incidence of end-stage renal disease secondary to glomerulonephritis: influence of the histologic type and presence of arterial hypertension

OBJETIVO: Avaliar retrospectivamente a associaçäo entre raça e incidência de doença renal terminal (DRT) em pacientes com glomerulonefrites em um Hospital Universitário do estado da Bahia. METODOS: A amostra foi composta de 79 pacientes com esclerose glomerular focal (EGF), 50 com glomerulonefrite membranoproliferativa (GNMP) e 44 com outros tipos de glomerulonefrites (OTGN), acompanhados entre 1970 e 1996 por pelo menos 6 meses. NÒo foram incluídos os pacientes com glomerulonefrite aguda, formas crescenticas, lesäo mínima, doenças do colágeno e com níveis de creatinina séica maior ou igual a 4 mg/dl. Quanto à raça, os pacientes foram classificados em brancos, mulatos ou negros. Para idades superiores a 18 anos e na ausência de uso de anti-hipertensivos, definiu-se como hipertensos pacientes que tiveram mÚdias das três primeiras determinaçöes da pressäo arterial sistólica ou diastólica iguais ou superiores a 140 e 90 mmHg, respectivamente; para idades igual ou abaixo de 18 anos foram utilizados critérios recomendados pela "Task Force on Blood Pressure in Children". RESULTADOS: No grupo de normotensos, a incidência de DRT foi 72 por cento menor em mulatos e negros (risco relativo (RR)=0,28; intervalo de confiança (IC) 95 por cento=0,11-0,67). No grupo de hipertensos, a associaçäo entre raça e DRT apresentou direçäo inversa (RR=1,49; IC 95 por cento=0,68-4,34; p=0,316) à observada em normotensos. Esta variaçäo no RR de acordo com a presenç ou ausência de HA foi estatisticamente significante (p=0,01). Entre os normotensos, parte da diferença racial na incidência de DRT pode ser explicada pela distribuiçäo de tipos histológicos de glomerulonefrite entre o grupo de brancos e o grupo de negros e mulatos. CONCLUSOES: Entre os normotensos com glomerulonefrite, a incidência de DRT foi significantemente maior em brancos do que em negros ou mulatos. Contrariamente, entre os hipertensos observou-se uma tendência para um risco maior de DRT no grupo de negros e mulatos. O estudo sugere que HA e o tipo histológico de glomerulonefrite influenciam a associaçäo entre raça e DRT

[Racial differences between patients with focal segmental glomerulosclerosis and membranoproliferative glomerulonephritis from the State of Bahia]. / Diferenças raciais entre pacientes com esclerose glomerular focal e glomerulonefrite membranoproliferativa residentes no estado da Bahia.

OBJECTIVE: To assess the association between race and type of glomerulonephritis, taking into account age, gender and the presence of hepatosplenic schistosomiasis mansoni. METHODS: Patients from the Renal Service of the Federal University of Bahia, Brazil, 80 with focal segmental glomerulosclerosis (FSG) and 50 with membranoproliferative glomerulonephritis (MPGN) were compared regarding the distribution of the racial types (black, mulatto, white). Patients with systemic lupus erythematosus or any kind of autoimmune disease were not included in the present analysis. Adjusted comparisons were performed using the Mantel-Haenszel method and a multivariate logistic regression model. RESULTS: Race was significantly associated with histologic type; the odds of being classified as black or mulatto were approximately 2.4 times higher (odds ratio = 2.43; IC 95% = 1.09-5.45) in patients with FSG than in those with MPGN. The association between race and histologic type was not influenced by the potential effects of age, gender and hepatosplenic schistosomiasis. In the multivariate logistic regression model, race was significantly associated (p = 0.037) with type of glomerulonephritis (odds ratio = 2.54; IC 95% = 1.06-6.06). CONCLUSION: A higher frequency of negroes and mulattoes in the FSG group (compared with MPGN) in this sample from the State of Bahia is consistent with findings of previous studies from the United States. The data support the possibility of a greater susceptibility to FSG among negroes and mulattoes, independently of age, gender and schistosomiasis. The identification of the mechanisms that determine this racial difference represents an important question for future investigations.

Diferenças raciais entre pacientes com esclerose glomerular focal e glomerulonefrite membranoproliferativa em residentes no estado da Bahia / Racial differences between patients with focal segmental glomerulosclerosis and membranoproliferative glomerulonephritis from the State of Bahia

Objetivo. Avaliar a relaçao entre raça e tipo histológico de glomerulomefrite, levando em consideraçao idade, sexo e presença da forma hepatoesplênica da esquistossomose mansônica. Material e Métodos. Pacientes do Serviço de Nefrologia da Universidade Federal da Bahia, 80 com esclerose glomerular focal (EGF) e 50 com glomerulonefrite membranoproliferativa (GNMP) foram comparados quanto à distribuiçao dos tipos raciais (negro, mulato, branco). Pacientes com lupus eritematoso sistêmico ou qualquer outro tipo de doença auto-imune nao foram incluídos na presente análise. Comparaçoes ajustadas foram feitas através do método de Mantel-Haenszel e de um modelo de regressao logística múltipla. Resultados. Raça foi significantemente associada com o tipo histológico; a relaçao entre o número de negros ou mulatos e o número de brancos foi aproximadamente 2,4 vezes maior (odds ratio=2,43; IC 95 por cento=1,09-5,45) em pacientes com EGF do que em pacientes com GNMP. Esta associaçao entre raça e tipo histológico foi independente da idade, do sexo e da presença da forma hepatoesplênica da esquistossomose. No modelo de regressao logística múltipla, raça foi significativamente (p=0,037) associada com o tipo histológico (odds ratio=2,54; IC 95 por cento=1,06-6,06). Conclusao. A maior freqüência de negros e mulatos no grupo EGF nesta amostra de pacientes da Bahia é consistente com os achados de estudos realizados nos Estados Unidos. Os dados apoiam a posibilidade de uma relaçao entre descendência africana e susceptibilidade aumentada para EGF, independente da idade, do sexo e do diagnóstico de esquistossomose. A identificaçao dos mecanismos que determinam esta diferença racial representa uma importante questao para futuras investigaçoes.

Combate a esquistossomiase. / Fight against schistosomiasis

Trabalho de revisao cujo objetivo e demonstrar o quadro atual da esquistossomiase, indicando os principais agentes utilizaveis das diferentes classes quimicas, apresentando efeitos farmacologicos e principais efeitos adversos

Latenciaçäo de agentes esquistossomicidas e antimalarios / Latentiation of schistosomicidal and antimalarial agents

Atraves do uso da latenciacao, foram preparados pro-farmacos de agentes antimalaricos (dapsona, trimetoprina, cicloguanila, pirimetamina, sulfamonometoxina, sulfadiazina, sulfamerazina e sulfatiazol) e agentes esquistossomicidas (oxamniquina anfotalida e pararrosanilina). Os produtos foram obtidos mediante reacao dos agentes ativos com o acido metacrilico, resultando os monomeros, e com o acido metacrilico, resultando os monomeros, e com o acido polimetacrilico, originando os polimeros. Submetidos a ensaios biológicos, a maioria mostrou atividade