995 resultados para Radiation Pattern


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Outgoing radiation is introduced in the framework of the classical predictive electrodynamics using LorentzDiracs equation as a subsidiary condition. In a perturbative scheme in the charges the first radiative self-terms of the accelerations, momentum and angular momentum of a two charge system without external field are calculated.

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We deal with a classical predictive mechanical system of two spinless charges where radiation is considered and there are no external fields. The terms (2,2)Paa of the expansion in the charges of the HamiltonJacobi momenta are calculated. Using these, together with known previous results, we can obtain the paa up to the fourth order. Then we have calculated the radiated energy and the 3-momentum in a scattering process as functions of the impact parameter and the incident energy for the former and 3-momentum for the latter. Scattering cross-sections are also calculated. Good agreement with well known results, including those of quantum electrodynamics, has been found.

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Methylmalonyl-CoA mutase (MCM) and propionyl-CoA carboxylase (PCC) are the key enzymes of the catabolic pathway of propionate metabolism and are mainly expressed in liver, kidney and heart. Deficiency of these enzymes leads to two classical organic acidurias: methylmalonic and propionic aciduria. Patients with these diseases suffer from a whole spectrum of neurological manifestations that are limiting their quality of life. Current treatment does not seem to effectively prevent neurological deterioration and pathophysiological mechanisms are poorly understood. In this article we show evidence for the expression of the catabolic pathway of propionate metabolism in the developing and adult rat CNS. Both, MCM and PCC enzymes are co-expressed in neurons and found in all regions of the CNS. Disease-specific metabolites such as methylmalonate, propionyl-CoA and 2-methylcitrate could thus be formed autonomously in the CNS and contribute to the pathophysiological mechanisms of neurotoxicity. In rat embryos (E15.5 and E18.5), MCM and PCC show a much higher expression level in the entire CNS than in the liver, suggesting a different, but important function of this pathway during brain development.

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Background: To compare the characteristics and prognostic features of ischemic stroke in patients with diabetes and without diabetes, and to determine the independent predictors of in-hospital mortality in people with diabetes and ischemic stroke.Methods: Diabetes was diagnosed in 393 (21.3%) of 1,840 consecutive patients with cerebral infarction included in a prospective stroke registry over a 12-year period. Demographic characteristics, cardiovascular risk factors, clinical events, stroke subtypes, neuroimaging data, and outcome in ischemic stroke patients with and without diabetes were compared. Predictors of in-hospital mortality in diabetic patients with ischemic stroke were assessed by multivariate analysis. Results: People with diabetes compared to people without diabetes presented more frequently atherothrombotic stroke (41.2% vs 27%) and lacunar infarction (35.1% vs 23.9%) (P < 0.01). The in-hospital mortality in ischemic stroke patients with diabetes was 12.5% and 14.6% in those without (P = NS). Ischemic heart disease, hyperlipidemia, subacute onset, 85 years old or more, atherothrombotic and lacunar infarcts, and thalamic topography were independently associated with ischemic stroke in patients with diabetes, whereas predictors of in-hospital mortality included the patient's age, decreased consciousness, chronic nephropathy, congestive heart failure and atrial fibrillation. Conclusion: Ischemic stroke in people with diabetes showed a different clinical pattern from those without diabetes, with atherothrombotic stroke and lacunar infarcts being more frequent. Clinical factors indicative of the severity of ischemic stroke available at onset have a predominant influence upon in-hospital mortality and may help clinicians to assess prognosis more accurately.

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OBJECTIVE: Glycodelin (PP14) is produced by the epithelium of the endometrium and its determination in the serum is used for functional evaluation of this tissue. Given the complex regulation and the combined contraceptive and immunosuppressive roles of glycodelin, the current lack of normal values for its serum concentration in the physiological menstrual cycle, derived from a large sample number, is a problem. We have therefore established reference values from over 600 sera. DESIGN: Retrospective study using banked serum samples. SETTING: University hospital. METHODS: Measurement of blood samples daily or every second day during one full cycle. MAIN OUTCOME MEASURES: Serum concentrations of glycodelin and normal values for every such one- or two-day interval were calculated. Late luteal phase glycodelin levels were compared with ovarian hormones. Follicular phase levels were compared with stimulated cycles from patients undergoing in vitro fertilization. RESULTS: Glycodelin concentrations were low around ovulation. Highest levels were observed at the end of the luteal phase; the glycodelin serum peak was reached 6-8 days after the one for progesterone. Late luteal glycodelin levels correlated negatively with the body mass index and positively with the progesterone level earlier in the secretory (mid-luteal) phase in the same woman. No associations with other ovarian hormones were observed. Follicular phase glycodelin levels were higher in the spontaneous than in the in vitro fertilization cycles. CONCLUSIONS: Normal values taken at two- or one-day intervals demonstrate the very late appearance of high serum glycodelin levels during the physiological menstrual cycle and their correlation with progesterone occurring earlier in the cycle.

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We conducted a genome-wide association study for androgenic alopecia in 1,125 men and identified a newly associated locus at chromosome 20p11.22, confirmed in three independent cohorts (n = 1,650; OR = 1.60, P = 1.1 x 10(-14) for rs1160312). The one man in seven who harbors risk alleles at both 20p11.22 and AR (encoding the androgen receptor) has a sevenfold-increased odds of androgenic alopecia (OR = 7.12, P = 3.7 x 10(-15)).

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We analyze the dynamics of a transient pattern formation in the Fréedericksz transition corresponding to a twist geometry. We present a calculation of the time-dependent structure factor based on a dynamical model which incorporates consistently the coupling of the director field with the velocity flow and also the effect of fluctuations. The appearance and development of a characteristic periodicity is described in terms of the time dependence of the maximum of the structure factor. We find a well-defined time for the appearance of the pattern and a subsequent stage of pattern development in which the characteristic periodicity tends to an asymptotic value.

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A nonlinear calculation of the dynamics of transient pattern formation in the Fréedericksz transition is presented. A Gaussian decoupling is used to calculate the time dependence of the structure factor. The calculation confirms the range of validity of linear calculations argued in earlier work. In addition, it describes the decay of the transient pattern.

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BACKGROUND: MR tissue tagging allows the noninvasive assessment of the locally and temporally resolved motion pattern of the left ventricle. Alterations in cardiac torsion and diastolic relaxation of the left ventricle were studied in patients with aortic stenosis and were compared with those of healthy control subjects and championship rowers with physiological volume-overload hypertrophy. METHODS AND RESULTS: Twelve aortic stenosis patients, 11 healthy control subjects with normal left ventricular function, and 11 world-championship rowers were investigated for systolic and diastolic heart wall motion on a basal and an apical level of the myocardium. Systolic torsion and untwisting during diastole were examined by use of a novel tagging technique (CSPAMM) that provides access to systolic and diastolic motion data. In the healthy heart, the left ventricle performs a systolic wringing motion, with a counterclockwise rotation at the apex and a clockwise rotation at the base. Apical untwisting precedes diastolic filling. In the athlete's heart, torsion and untwisting remain unchanged compared with those of the control subjects. In aortic stenosis patients, torsion is significantly increased and diastolic apical untwisting is prolonged compared with those of control subjects or athletes. CONCLUSIONS: Torsional behavior as observed in pressure- and volume-overloaded hearts is consistent with current theoretical findings. A delayed diastolic untwisting in the pressure-overloaded hearts of the patients may contribute to a tendency toward diastolic dysfunction.

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Résumé : Le glioblastome (GBM, WHO grade IV) est la tumeur cérébrale primaire la plus fréquente et la plus maligne, son pronostic reste très réservé et sa réponse aux différents traitements limitée. Récemment, une étude clinique randomisée (EORTC 26981/NCIC CE.3) a démontré que le traitement combiné de temozolomide et radiothérapie (RT/TMZ) est le meilleur dans les cas de GBM nouvellement diagnostiqués [1]. Cependant, seul un sous-groupe de patients bénéficie du traitement RT/TMZ et même parmi eux, leur survie reste très limitée. Pour tenter de mieux comprendre les réponses au traitement RT/TMZ, la biologie du GBM, identifier d'autres facteurs de résistance et découvrir de nouvelles cibles aux traitements, nous avons conduit une analyse moléculaire étendue à 73 patients inclus dans cette étude clinique. Nous avons complété les résultats moléculaires déjà obtenus par un profil génomique du nombre de copies par Array Comparative Genomic Hybridization. Afin d'atteindre nos objectifs, nous avons analysé en parallèle les données cliniques des patients et leurs profils moléculaires. Nos résultats confirment des analyses connues dans le domaine des aberrations du nombre de copies (CNA) et de profils du glioblastome. Nous avons observé une bonne corrélation entre le CNA génomique et l'expression de l'ARN messager dans le glioblastome et identifié un nouveau modèle de CNA du chromosome 7 pouvant présenter un intérêt clinique. Nous avons aussi observé par l'analyse du CNA que moins de 10% des glioblastomes conservent leurs mécanismes de suppression de tumeurs p53 et Rb1. Nous avons aussi observé que l'amplification du CDK4 peut constituer un facteur supplémentaire de résistance au traitement RT/TMZ, cette observation nécessite confirmation sur un plus grand nombre d'analyses. Nous avons montré que dans notre analyse des profils moléculaires et cliniques, il n'est pas possible de différencier le GBM à composante oligodendrogliale (GBM-O) du glioblastome. En superposant les profils moléculaires et les modèles expérimentaux in vitro, nous avons identifié WIF-1 comme un gène suppresseur de tumeur probable et une activation du signal WNT dans la pathologie du glioblastome. Ces observations pourraient servir à une meilleure compréhension de cette maladie dans le futur. Abstract : Glioblastoma, (GBM, WHO grade IV) is the most malignant and most frequent primary brain tumor with a very poor prognosis and response to therapy. A recent randomized clinical trial (EORTC26981/NCIC CE.3) established RT/TMZ as the 1St effective chemo-radiation therapy in newly diagnosed GBM [1]. However only a genetic subgroup of patients benefit from RT/TMZ and even in this subgroup overall survival remains very dismal. To explain the observed response to RT/TMZ, have a better understanding of GBM biology, identify other resistance factors and discover new drugable targets a comprehensive molecular analysis was performed in 73 of these GBM trial cohort. We complemented the available molecular data with a genomic copy number profiling by Array Comparative Genomic Hybridization. We proceeded to align the molecular profiles and the Clinical data, to meet our project objectives. Our data confirm known GBM Copy Number Aberrations and profiles. We observed a good correlation of genomic CN and mRNA expression in GBM, and identified new interesting CNA pattern for chromosome 7 with a potential clinical value. We also observed that by copy number aberration data alone, less than 10% of GBM have an intact p53 and Rb1 tumor .suppressor pathways. We equally observed that CDK4 amplification might constitute an additional RT/TMZ resistant factor, an observation that will need confirmation in a larger data set. We show that the molecular and clinical profiles in our data set, does not support the identification of GBM-O as a new entity in GBM. By combining the molecular profiles and in vitro model experiments we identify WIF1 as a potential GBM TSG and an activated WNT signaling as a pathologic event in GBM worth incorporation in attempts to better understand and impact outcome in this disease.

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AIMS: In patients with alcohol dependence, health-related quality of life (QOL) is reduced compared with that of a normal healthy population. The objective of the current analysis was to describe the evolution of health-related QOL in adults with alcohol dependence during a 24-month period after initial assessment for alcohol-related treatment in a routine practice setting, and its relation to drinking pattern which was evaluated across clusters based on the predominant pattern of alcohol use, set against the influence of baseline variables METHODS: The Medical Outcomes Study 36-Item Short-Form Survey (MOS-SF-36) was used to measure QOL at baseline and quarterly for 2 years among participants in CONTROL, a prospective observational study of patients initiating treatment for alcohol dependence. The sample consisted of 160 adults with alcohol dependence (65.6% males) with a mean (SD) age of 45.6 (12.0) years. Alcohol use data were collected using TimeLine Follow-Back. Based on the participant's reported alcohol use, three clusters were identified: 52 (32.5%) mostly abstainers, 64 (40.0%) mostly moderate drinkers and 44 (27.5%) mostly heavy drinkers. Mixed-effect linear regression analysis was used to identify factors that were potentially associated with the mental and physical summary MOS-SF-36 scores at each time point. RESULTS: The mean (SD) MOS-SF-36 mental component summary score (range 0-100, norm 50) was 35.7 (13.6) at baseline [mostly abstainers: 40.4 (14.6); mostly moderate drinkers 35.6 (12.4); mostly heavy drinkers 30.1 (12.1)]. The score improved to 43.1 (13.4) at 3 months [mostly abstainers: 47.4 (12.3); mostly moderate drinkers 44.2 (12.7); mostly heavy drinkers 35.1 (12.9)], to 47.3 (11.4) at 12 months [mostly abstainers: 51.7 (9.7); mostly moderate drinkers 44.8 (11.9); mostly heavy drinkers 44.1 (11.3)], and to 46.6 (11.1) at 24 months [mostly abstainers: 49.2 (11.6); mostly moderate drinkers 45.7 (11.9); mostly heavy drinkers 43.7 (8.8)]. Mixed-effect linear regression multivariate analyses indicated that there was a significant association between a lower 2-year follow-up MOS-SF-36 mental score and being a mostly heavy drinker (-6.97, P < 0.001) or mostly moderate drinker (-3.34 points, P = 0.018) [compared to mostly abstainers], being female (-3.73, P = 0.004), and having a Beck Inventory scale score ≥8 (-6.54, P < 0.001), at baseline. The mean (SD) MOS-SF-36 physical component summary score was 48.8 (10.6) at baseline, remained stable over the follow-up and did not differ across the three clusters. Mixed-effect linear regression univariate analyses found that the average 2-year follow-up MOS-SF-36 physical score was increased (compared with mostly abstainers) in mostly heavy drinkers (+4.44, P = 0.007); no other variables tested influenced the MOS-SF-36 physical score. CONCLUSION: Among individuals with alcohol dependence, a rapid improvement was seen in the mental dimension of QOL following treatment initiation, which was maintained during 24 months. Improvement was associated with the pattern of alcohol use, becoming close to the general population norm in patients classified as mostly abstainers, improving substantially in mostly moderate drinkers and improving only slightly in mostly heavy drinkers. The physical dimension of QOL was generally in the normal range but was not associated with drinking patterns.