Gamma Radiation Effects on Peanut Skin Antioxidants

Peanut skin, which is removed in the peanut blanching process, is rich in bioactive compounds with antioxidant properties. The aims of this study were to measure bioactive compounds in peanut skins and evaluate the effect of gamma radiation on their antioxidant activity. Peanut skin samples were treated with 0.0, 5.0, 7.5, or 10.0 kGy gamma rays. Total phenolics, condensed tannins, total flavonoids, and antioxidant activity were evaluated. Extracts obtained from the peanut skins were added to refined-bleached-deodorized (RBD) soybean oil. The oxidative stability of the oil samples was determined using the Oil Stability Index method and compared to a control and synthetic antioxidants (100 mg/kg BHT and 200 mg/kg TBHQ). Gamma radiation changed total phenolic content, total condensed tannins, total flavonoid content, and the antioxidant activity. All extracts, gamma irradiated or not, presented increasing induction period (h), measured by the Oil Stability Index method, when compared with the control. Antioxidant activity of the peanut skins was higher than BHT. The present study confirmed that gamma radiation did not affect the peanut skin extracts' antioxidative properties when added to soybean oil.

DNA fragmentation by gamma radiation and electron beams using atomic force microscopy

Double-stranded pBS plasmid DNA was irradiated with gamma rays at doses ranging from 1 to 12 kGy and electron beams from 1 to 10 kGy. Fragment-size distributions were determined by direct visualization, using atomic force microscopy with nanometer-resolution operating in non-tapping mode, combined with an improved methodology. The fragment distributions from irradiation with gamma rays revealed discrete-like patterns at all doses, suggesting that these patterns are modulated by the base pair composition of the plasmid. Irradiation with electron beams, at very high dose rates, generated continuous distributions of highly shattered DNA fragments, similar to results at much lower dose rates found in the literature. Altogether, these results indicate that AFM could supplement traditional methods for high-resolution measurements of radiation damage to DNA, while providing new and relevant information.

Agronomic characterization of banana mutants obtained by gamma radiation

Banana is one of the most economically important fruit, explored almost exclusively by small producers as a continuous source of food and income. Although Brazil is one of the main banana producers, the national banana production is undergoing serious problems especially in the phases of production and post-harvest limiting its participation in the international market. One of the main factors leading to great production losses is the toppling over due to the tall height of plants of main commercial cultivars. A strategy to solve this problem is reducing height by inducing mutation. The objective of the present work was to characterize irradiated Prata type banana mutants (cvs. Pacovan and Preciosa) during two production cycles in order to select short plants in height with good agronomic characteristics. In vitro plants of both cultivars were irradiated with gamma rays in the doses of 20 Gy ('Pacovan', 200 plants) and 30 Gy ( 'Preciosa', 200 plants) subcultivated four times and afterwards evaluated in the field during two production cycles. Four possible mutants were selected from each cultivar with height smaller than the average height of the controls after two evaluation cycles. It was observed that some of these mutants presented greater precocity and bunch weight compared to the controls. From the results obtained it is possible to select mutant plants with superior agronomic characteristics for 'Pacovan' as well as 'Preciosa' submitted to gamma radiation.

Prospect on intergalactic magnetic field measurements with gamma-ray instruments

Observing high-energy gamma-rays from Active Galactic Nuclei (AGN) offers a unique potential to probe extremely tiny values of the intergalactic magnetic field (IGMF), a long standing question of astrophysics, astropa rticle physics and cosmology. Very high energy (VHE) photons from blazars propagating along the line of sight interact with the extragalactic background light (EBL) and produce e + e − pairs. Through inverse-Compton interaction, mainly on the cosmic microwave background (CMB), these pairs generate secondary GeV-TeV compo- nents accompanying the primary VHE signal. Such secondary components would be detected in the gamma-ray range as delayed “pair echos” for very weak IGMF ( B< 10 − 16 G ), while they should result in a spatially extended ga mma-ray emission around the source for higher IGMF values ( B> 10 − 16 G ). Coordinated observations with space (i.e. Fermi) and ground- based gamma-ray instruments, such as the pre sent Cherenkov experiments H.E.S.S., MAGIC and VERITAS, the future Cherenkov Telescope Array (CTA) Observatory, and the wide-field detectors such as HAWC and LHAASO, should allow to analyze and finally detect such echos, extended emission or pair halos, and to further characterize the IGMF.

Thallium Bromide Deposited Using Spray Coating

Spray coating was used to produce thallium bromide samples on glass substrates. The influence of several fabrication parameters on the final structural properties of the samples was investigated. Substrate position, substrate temperature, solution concentration, carrying gas, and solution flow were varied systematically, the physical deposition mechanism involved in each case being discussed. Total deposition time of about 3.5 h can lead to 62-mu m-thick films, comprising completely packed micrometer-sized crystalline grains. X-ray diffraction and scanning electron microscopy were used to characterize the samples. On the basis of the experimental data, the optimum fabrication conditions were identified. The technique offers an alternative method for fast, cheap fabrication of large-area devices for the detection of high-energy radiation, i.e., X-rays and gamma-rays, in medical imaging.

Further investigating the determination of phosphorus in plants by INAA using bremsstrahlung measurement

Phosphorus is an essential element for plants and animals, playing a fundamental role in the production of biochemical energy. Despite its relevance, phosphorus is not commonly determined by instrumental neutron activation analysis (INAA), because (32)P does not emit gamma-rays in its decay. There are alternative methods for the determination of phosphorus by INAA, such as the use of beta counting or the measurement of bremsstrahlung originated from the high energy beta particle from (32)P. Here the determination of phosphorus in plant materials by measuring the bremsstrahlung production was further investigated, to optimize an analytical protocol for minimizing interferences and overcoming the poor specificity. Eight certified reference materials of plant matrices with phosphorus ranging between 171 and 5,180 mg kg(-1) were irradiated at a thermal neutron flux of 9.5 x 10(12) cm(-2) s(-1) and measured with a HPGe detector at decay times varying from 7 to 60 days. Phosphorus solutions added to a certified reference material at three levels were used for calibration. Counts accumulated in the baseline at four different regions of the gamma-ray spectra were tested for the determination of phosphorus, with better results for the 100 keV region. The Compton scattering contribution in the selected range was discounted using an experimental peak-to-Compton factor and the net areas of all peaks in the spectra with energies higher than 218 keV, i.e. Compton edge above 100 keV. Amongst the interferences investigated, the production of (32)P from sulfur, and the contribution of Compton scattering should be considered for producing good results.

Color Dependence on Thickness in Topaz Crystal from Brazil

It is well known that crystals of topaz from the Eastern Brazilian Pegmatite Province may turn blue by the irradiation with Co-60 gamma rays followed by heat treatment. Also, it is known that the sensation of color changes with the thickness of these crystals. The dependence of the color, given by 1931 CIE chromaticity coordinates, with the thickness of the crystal was analyzed. The absorbance used in the calculation of these coordinates was given by the sum of Gaussian lines. The parameters of these lines were determined through the decomposition of the optical absorption spectra in the ultraviolet and visible regions. The decomposition revealed several lines, whose assignment was made considering studies in spodumene and beryl crystals and highly accurate quantum mechanical calculations. The transmittance becomes very narrow with increasing thickness, and the CIE chromaticity coordinates converge to the borderline of the CIE Chromaticity Diagram at the wavelength of maximum transmittance. Furthermore, the purity of color increases with increasing thickness, and the dominant wavelength reaches the wavelength of maximum transmittance.

FIG CLONES SELECTION OF cv. ROXO DE VALINHOS OBTAINED BY IRRADIATED BUDS

The fig tree (Ficus carica L.) is a fruit tree of great world importance and, therefore, the genetic improvement becomes an important field of research for the crop improvement, being necessary to gather information on this species, mainly regarding its genetic variability so that appropriate propagation projects and management are made. However, the fig, in Brazil, is all produced from only one cultivar, Roxo de Valinhos, which produces seedless fruit, making impossible the conventional breeding. So, the fig breeding through induced mutagenic becomes a very important research line, greatly contributing to the fig culture development. The objective of this study was to select fig plants formed by cuttings treated with gamma ray. The plants used were obtained from buds of the cv. Roxo de Valinhos. The cuttings were irradiated with gamma rays in an irradiator Gamma Cell at 10 cm from the tip of the cutting, at doses of 30 Gy with dose rate of 238 Gy/h. The experiment consisted of 450 treatments, where each formed plant was a treatment. The treatments were numbered sequentially from 1 to 450 and spaced 2.5 x 1.5 m. It was evaluated the vegetative and the fruits characteristics, and the incidence of major crop pests and diseases. The analysis data showed that there is genetic variability among treatments and that the plants under numbers 1, 5, 20, 79, 164, 189, 194, 201, 221, 214, 258, 301, 322, 392, 433 and 440 are probably genetic mutants that should be tested as commercial orchards.

A search for point sources of EeV neutrons

A thorough search of the sky exposed at the Pierre Auger Cosmic Ray Observatory reveals no statistically significant excess of events in any small solid angle that would be indicative of a flux of neutral particles from a discrete source. The search covers from -90 degrees to +15 degrees in declination using four different energy ranges above 1 EeV (10(18) eV). The method used in this search is more sensitive to neutrons than to photons. The upper limit on a neutron flux is derived for a dense grid of directions for each of the four energy ranges. These results constrain scenarios for the production of ultrahigh energy cosmic rays in the Galaxy.

Introducing the CTA concept

The Cherenkov Telescope Array (CTA) is a new observatory for very high-energy (VHE) gamma rays. CTA has ambitions science goals, for which it is necessary to achieve full-sky coverage, to improve the sensitivity by about an order of magnitude, to span about four decades of energy, from a few tens of GeV to above 100 TeV with enhanced angular and energy resolutions over existing VHE gamma-ray observatories. An international collaboration has formed with more than 1000 members from 27 countries in Europe, Asia, Africa and North and South America. In 2010 the CTA Consortium completed a Design Study and started a three-year Preparatory Phase which leads to production readiness of CTA in 2014. In this paper we introduce the science goals and the concept of CTA, and provide an overview of the project.

Tauroursodeoxycholic Acid Affects PPAR gamma and TLR4 in Steatotic Liver Transplantation

Numerous steatotic livers are discarded for transplantation because of their poor tolerance to ischemia-reperfusion (I/R). We examined whether tauroursodeoxycholic acid (TUDCA), a known inhibitor of endoplasmic reticulum (ER) stress, protects steatotic and nonsteatotic liver grafts preserved during 6 h in University of Wisconsin (UW) solution and transplanted. The protective mechanisms of TUDCA were also examined. Neither unfolded protein response (UPR) induction nor ER stress was evidenced in steatotic and nonsteatotic liver grafts after 6 h in UW preservation solution. TUDCA only protected steatotic livers grafts and did so through a mechanism independent of ER stress. It reduced proliferator-activated receptor-gamma(PPAR gamma) and damage. When PPAR gamma was activated, TUDCA did not reduce damage. TUDCA, which inhibited PPAR gamma, and the PPAR gamma antagonist treatment up-regulated toll-like receptor 4 (TLR4), specifically the TIR domain-containing adaptor inducing IFN beta (TRIF) pathway. TLR4 agonist treatment reduced damage in steatotic liver grafts. When TLR4 action was inhibited, PPAR gamma antagonists did not protect steatotic liver grafts. In conclusion, TUDCA reduced PPAR gamma and this in turn up-regulated the TLR4 pathway, thus protecting steatotic liver grafts. TLR4 activating-based strategies could reduce the inherent risk of steatotic liver failure after transplantation.

A search for anisotropy in the arrival directions of ultra high energy cosmic rays recorded at the Pierre Auger Observatory

Observations of cosmic rays arrival directions made with the Pierre Auger Observatory have previously provided evidence of anisotropy at the 99% CL using the correlation of ultra high energy cosmic rays (UHECRs) with objects drawn from the Veron-Cetty Veron catalog. In this paper we report on the use of three catalog independent methods to search for anisotropy. The 2pt-L, 2pt+ and 3pt methods, each giving a different measure of self-clustering in arrival directions, were tested on mock cosmic ray data sets to study the impacts of sample size and magnetic smearing on their results, accounting for both angular and energy resolutions. If the sources of UHECRs follow the same large scale structure as ordinary galaxies in the local Universe and if UHECRs are deflected no more than a few degrees, a study of mock maps suggests that these three method can efficiently respond to the resulting anisotropy with a P-value = 1.0% or smaller with data sets as few as 100 events. using data taken from January 1, 2004 to July 31, 2010 we examined the 20, 30, ... , 110 highest energy events with a corresponding minimum energy threshold of about 49.3 EeV. The minimum P-values found were 13.5% using the 2pt-L method, 1.0% using the 2pt+ method and 1.1% using the 3pt method for the highest 100 energy events. In view of the multiple (correlated) scans performed on the data set, these catalog-independent methods do not yield strong evidence of anisotropy in the highest energy cosmic rays.

Bivariate gamma-geometric law and its induced Levy process

In this article we introduce a three-parameter extension of the bivariate exponential-geometric (BEG) law (Kozubowski and Panorska, 2005) [4]. We refer to this new distribution as the bivariate gamma-geometric (BGG) law. A bivariate random vector (X, N) follows the BGG law if N has geometric distribution and X may be represented (in law) as a sum of N independent and identically distributed gamma variables, where these variables are independent of N. Statistical properties such as moment generation and characteristic functions, moments and a variance-covariance matrix are provided. The marginal and conditional laws are also studied. We show that BBG distribution is infinitely divisible, just as the BEG model is. Further, we provide alternative representations for the BGG distribution and show that it enjoys a geometric stability property. Maximum likelihood estimation and inference are discussed and a reparametrization is proposed in order to obtain orthogonality of the parameters. We present an application to a real data set where our model provides a better fit than the BEG model. Our bivariate distribution induces a bivariate Levy process with correlated gamma and negative binomial processes, which extends the bivariate Levy motion proposed by Kozubowski et al. (2008) [6]. The marginals of our Levy motion are a mixture of gamma and negative binomial processes and we named it BMixGNB motion. Basic properties such as stochastic self-similarity and the covariance matrix of the process are presented. The bivariate distribution at fixed time of our BMixGNB process is also studied and some results are derived, including a discussion about maximum likelihood estimation and inference. (C) 2012 Elsevier Inc. All rights reserved.

Fc gamma Receptor Gene Polymorphisms in Childhood Immune Thrombocytopenic Purpura

Immune thrombocytopenic purpura (ITP) is a common hematological disorder in the childhood, and it is one of the most common forms of autoimmune disease in pediatric patients. The ITP basis is a primary dysfunction of the immune system. This study aimed to analyze the genetic polymorphisms of the Fc gamma receptors IIA and IIIA. The genetic polymorphisms of the Fc receptors gamma IIA (131H/R) and gamma RIIIA (158V/F) were analyzed by polymerase chain reaction-restriction fragment length polymorphism technique. Odds ratio and 95% confidence interval were calculated by chi(2) test. Homozygous polymorphic genotype for the Fc gamma RIIIA was significantly more frequent among patients compared with controls (odds ratio = 0.27; 95% confidence interval, 0.09-0.80; P = 0.03). There was no statistical difference between the ITP group and the controls in the analysis of combinations of alleles of the high-affinity Fc receptor, but the ITP individuals with this combination had a lower duration of disease (P = 0.01). Genetic polymorphisms in immune system genes can be important for ITP pathogenesis and disease outcome.

Interferon-gamma and interleukin-10 production by mononuclear cells from patients with advanced head and neck cancer

OBJECTIVE: This study aims to evaluate the production of interferon-gamma and interleukin-10 by stimulated peripheral blood mononuclear cells isolated from patients with supraglottic laryngeal cancer before and after surgical treatment. METHODS: Fourteen patients with advanced supraglottic laryngeal cancer were studied. Cultures of peripheral blood mononuclear cells isolated during the preoperative and late postoperative periods were stimulated with concanavalin A and Bacille Calmette-Guerin, and the supernatant concentrations of interferon-gamma and interleukin-10 were measured. RESULTS: For non-stimulated cultures, the interferon-gamma levels produced by the preoperative period and the late postoperative period cultures were lower than the levels produced by the control group cultures. The interferon-gamma levels after stimulation with concanavalin A were higher in the late postoperative period cultures than in the preoperative evaluation cultures. Stimulation with Bacille Calmette-Guerin led to the production of similar levels of interferon-gamma and interleukin-10 by all cultures; thus, stimulation increased the levels of interferon-gamma produced by both the preoperative and postoperative cultures relative to the levels produced by the corresponding unstimulated cultures. CONCLUSION: Patients with advanced supraglottic laryngeal cancer exhibit an in vitro deficiency in interferongamma secretion by mononuclear cells. Stimulated cells seem to recover this function during the postoperative period.