1,363 research outputs found

    Proton induced leakage current in CCDs

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    The effect of different proton fluences on the performance of two E2V Technologies CCD47-20 devices was investigated with particular emphasis given to the analysis of 'random telegraph signal' (RTS) generation, bright pixel generation and induced changes in base dark current level. The results show that bright pixel frequency increases as the mean energy of the proton beam is increased, and that the base dark current level after irradiation scales with the level of ionization damage. For the RTS study, 500 pixels on one device were monitored over a twelve hour period. This data set revealed a number of distinct types of pixel change level fluctuation and a system of classification has been devised. Previously published RTS data is discussed and reviewed in light of the new data

    The Coulomb phase shift revisited

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    We investigate the Coulomb phase shift, and derive and analyze new and more precise analytical formulae. We consider next to leading order terms to the Stirling approximation, and show that they are important at small values of the angular momentum ll and other regimes. We employ the uniform approximation. The use of our expressions in low energy scattering of charged particles is discussed and some comparisons are made with other approximation methods.Comment: 13 pages, 5 figures, 1 tabl

    Rare Earth Element Adsorption to Clay Minerals: Mechanistic Insights and Implications for Recovery from Secondary Sources

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    \ua9 2024 American Chemical Society.The energy transition will have significant mineral demands and there is growing interest in recovering critical metals, including rare earth elements (REE), from secondary sources in aqueous and sedimentary environments. However, the role of clays in REE transport and deposition in these settings remains understudied. This work investigated REE adsorption to the clay minerals illite and kaolinite through pH adsorption experiments and extended X-ray absorption fine structure (EXAFS). Clay type, pH, and ionic strength (IS) affected adsorption, with decreased adsorption under acidic pH and elevated IS. Illite had a higher adsorption capacity than kaolinite; however, >95% adsorption was achieved at pH ∼7.5 regardless of IS or clay. These results were used to develop a surface complexation model with the derived binding constants used to predict REE speciation in the presence of competing sorbents. This demonstrated that clays become increasingly important as pH increases, and EXAFS modeling showed that REE can exist as both inner- and outer-sphere complexes. Together, this indicated that clays can be an important control on the transport and enrichment of REE in sedimentary systems. These findings can be applied to identify settings to target for resource extraction or to predict REE transport and fate as a contaminant

    Bullying girls - Changes after brief strategic family therapy: A randomized, prospective, controlled trial with one-year follow-up

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    Background: Many girls bully others. They are conspicuous because of their risk-taking behavior, increased anger, problematic interpersonal relationships and poor quality of life. Our aim was to determine the efficacy of brief strategic family therapy (BSFT) for bullying-related behavior, anger reduction, improvement of interpersonal relationships, and improvement of health-related quality of life in girls who bully, and to find out whether their expressive aggression correlates with their distinctive psychological features. Methods: 40 bullying girls were recruited from the general population: 20 were randomly selected for 3 months of BSFT. Follow-up took place 12 months after the therapy had ended. The results of treatment were examined using the Adolescents' Risk-taking Behavior Scale (ARBS), the State-Trait Anger Expression Inventory (STAXI), the Inventory of Interpersonal Problems (IIP-D), and the SF-36 Health Survey (SF-36). Results: In comparison with the control group (CG) (according to the intent-to-treat principle), bullying behavior in the BSFT group was reduced (BSFT-G from n = 20 to n = 6; CG from n = 20 to n = 18, p = 0.05) and statistically significant changes in all risk-taking behaviors (ARBS), on most STAXI, IIP-D, and SF-36 scales were observed after BSFT. The reduction in expressive aggression (Anger-Out scale of the STAXI) correlated with the reduction on several scales of the ARBS, IIP-D, and SF-36. Follow-up a year later showed relatively stable events. Conclusions: Our findings suggest that bullying girls suffer from psychological and social problems which may be reduced by the use of BSFT. Expressive aggression in girls appears to correlate with several types of risk-taking behavior and interpersonal problems, as well as with health-related quality of life. Copyright (c) 2006 S. Karger AG, Basel

    Juvenile myoclonic epilepsy presenting as a new daily persistent-like headache

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    New daily persistent headache (NDPH) is a recognized subtype of chronic daily headache with a unique presentation of a daily headache from onset typically in individuals with minimal or no prior headache history. Various secondary mimics of NDPH have now been documented but at present there has been no association made between primary epilepsy syndromes and new daily persistent-like headaches. A case patient is presented who developed a daily continuous headache from onset who 3 months after headache initiation had her first generalized tonic-clonic seizure. Further investigation into her history and her specific EEG pattern suggested a diagnosis of juvenile myoclonic epilepsy (JME). Her NDPH and seizures ceased with epilepsy treatment. Clinically relevant was that the headache was the primary persistent clinical symptom of her JME before the onset of generalized tonic-clonic seizures. The current case report adds another possible secondary cause of new daily persistent-like headaches to the medical literature and suggests another association between primary epilepsy syndromes and distinct headache syndromes

    Serum methylarginines and spirometry-measured lung function in older adults

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    Rationale: Methylarginines are endogenous nitric oxide synthase inhibitors that have been implicated in animal models of lung disease but have not previously been examined for their association with spirometric measures of lung function in humans. Objectives: This study measured serum concentrations of asymmetric and symmetric dimethylarginine in a representative sample of older community-dwelling adults and determined their association with spirometric lung function measures. Methods: Data on clinical, lifestyle, and demographic characteristics, methylated arginines, and L-arginine (measured using LC-MS/MS) were collected from a population-based sample of older Australian adults from the Hunter Community Study. The five key lung function measures included as outcomes were Forced Expiratory Volume in 1 second, Forced Vital Capacity, Forced Expiratory Volume in 1 second to Forced Vital Capacity ratio, Percent Predicted Forced Expiratory Volume in 1 second, and Percent Predicted Forced Vital Capacity. Measurements and Main Results: In adjusted analyses there were statistically significant independent associations between a) higher asymmetric dimethylarginine, lower Forced Expiratory Volume in 1 second and lower Forced Vital Capacity; and b) lower L-arginine/asymmetric dimethylarginine ratio, lower Forced Expiratory Volume in 1 second, lower Percent Predicted Forced Expiratory Volume in 1 second and lower Percent Predicted Forced Vital Capacity. By contrast, no significant associations were observed between symmetric dimethylarginine and lung function. Conclusions: After adjusting for clinical, demographic, biochemical, and pharmacological confounders, higher serum asymmetric dimethylarginine was independently associated with a reduction in key measures of lung function. Further research is needed to determine if methylarginines predict the decline in lung function

    Solução glicosada hipertônica no mesentério e no peritônio de ratos: estudo macroscópico e microscópico

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    PURPOSE: The objective of the experimental study is to detect the macroscopic and microscopic alterations of the mesenterium and parietal peritoneum when hypertonic glucose aqueous solution 10%-25% is administrated into the peritoneal cavity of the rat. METHODS: 90 Wistar females young rats adults were used weighin between 180-250 g, numbered 1 to 90, establishing unique group and divided in three groups (A, B, C) of 30 animals chosen aleatory manner. 0,9% saline solution was used called control group, or group A, 10% glucose solution named group B, and in the others 30 was used 25% glucose solution named group C, differing in the observation period, (06h, 24h and 48h), but with the same procedure. A midline abdominal wall laparotomy was made and in the animals of the control group was injected 2 ml of a 0,9% saline solution into the peritoneal cavity. After, we made a suture in mass without to include the peritoneum. For the others groups (B, C) the rats received 10% glucose solution and 25% glucose solution injected into the peritoneal cavity respectively. All groups were kept under observation and the results were submitted to statistical analysis by a longitudinal and transversal comparative study. RESULTS: A new surgery was done in 6h, 24h and 48h, and we observed in macroscopic evaluation, the presence of fluid, serous uniforme and rosy all over the cavity. Vascular congestion was present. We dried out 90 fragments of mesenterium and 90 fragments of parietal peritonium bilateral. In the microscopic study, necrosis was not present. For the mesenterium histological study we observed 16 cases (17,8%) unspecific chronic inflammation, 30 cases (33,4%) hiperplasic linfonod, 10 cases (11,1%) high vascular congestion, 6 cases (6,6%) reaction fibrosis and 28 cases (31,1%) no alteration. For the parietal peritonium histological study we observed 6 cases (3,3%) reaction fibrosis and 174 cases (96,7%) no alteration. Giant cell was not present. In the statistical analisys statistic there is no significance between the groups (p>0,05). CONCLUSION: Hypertonic glucose solution and NaCl 0,9% on the mesenterium and parietal peritonium do not produce tissue necrosis in a rat and the inflammation process has the same intensity.OBJETIVO: Investigar as alterações macroscópicas e microscópicas do mesentério e do peritônio parietal quando se administra a solução aquosa de glicose hipertônica a 10% e a 25% na cavidade peritoneal de rato. MÉTODOS: 90 ratos fêmeas (n=90), adultos, Wistar, jovens, com peso variando de 180 a 250 gramas foram divididos em 3 sub-grupos (A, B e C) contendo cada um 30 animais com procedimentos idênticos, diferindo apenas no período de observação. Os números de 1 a 30 constituem o grupo A ou grupo-controle (NaCl 0,9%), os números de 31 a 60 constituem o grupo B ou grupo-glicose a 10% e os números de 61 a 90 constituem o grupo C ou grupo- glicose a 25%. Realizando-se posteriormente laparotomia com incisão mediana longitudinal de pele a 2 cm abaixo do processo Xiphoideus sterni, estendendo-se por 3 cm caudalmente na linha média ventral. A escolha do procedimento a ser realizado para introdução na cavidade peritoneal de 2 ml de uma solução de cloreto de sódio 0,9% (controle), de glicose hipertônica a 10% e de glicose hipertônica a 25%. Em períodos correspondentes às 6h, 24h e 48h de pós-operatório, os animais de cada grupo foram reoperados, sendo realizada avaliação macroscópica e microscópica além dos registros das alterações histológicas do mesentério e peritônio parietal. RESULTADOS: Na microscopia do mesentério observou-se que 30 animais (33,4%) apresentaram linfonodos hiperplásicos; 6 animais (6,6%) com fibrose reacional; 10 animais (11,1%) com intensa congestão vascular; 16 animais (17,8%) com inflamação crônica inespecífica; 28 casos (31,1%) sem alteração. A microscopia do peritônio revelou 6 casos com fibrose reacional (3,3%) 174 casos (96,7%) sem alteração histológica. CONCLUSÃO: As soluções de glicose a 10% e a 25% não causam necrose tecidual quando introduzidas na cavidade peritoneal. O processo reacional inflamatório é de igual intensidade tecidual comparando-se ao uso da solução de NaCl a 0,9%.UNCISAL DepartmentUFAL Morphology Department and Human AnatomyUNIFESP-EPM Surgery DepartmentUNIFESP, EPM, Surgery DepartmentSciEL

    Nucleocytoplasmic transport: a thermodynamic mechanism

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    The nuclear pore supports molecular communication between cytoplasm and nucleus in eukaryotic cells. Selective transport of proteins is mediated by soluble receptors, whose regulation by the small GTPase Ran leads to cargo accumulation in, or depletion from the nucleus, i.e., nuclear import or nuclear export. We consider the operation of this transport system by a combined analytical and experimental approach. Provocative predictions of a simple model were tested using cell-free nuclei reconstituted in Xenopus egg extract, a system well suited to quantitative studies. We found that accumulation capacity is limited, so that introduction of one import cargo leads to egress of another. Clearly, the pore per se does not determine transport directionality. Moreover, different cargo reach a similar ratio of nuclear to cytoplasmic concentration in steady-state. The model shows that this ratio should in fact be independent of the receptor-cargo affinity, though kinetics may be strongly influenced. Numerical conservation of the system components highlights a conflict between the observations and the popular concept of transport cycles. We suggest that chemical partitioning provides a framework to understand the capacity to generate concentration gradients by equilibration of the receptor-cargo intermediary.Comment: in press at HFSP Journal, vol 3 16 text pages, 1 table, 4 figures, plus Supplementary Material include
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