1,127 research outputs found

    Analytical Studies on the Structure and Emission of the SS433 Jets

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    We study the structure and emission of the SS 433 jets in the X-ray emitting region and in the inner and hotter portion inside the X-ray emitting region. In order to consider the jet structure from the inner to outer regions we develop the hybrid model combining the conical beam and the model beam whose cross section grows with the distance more slowly. We find that the jet beams in the inner and hotter portion are of two-temperature and emit a large amount of high energy gamma photons. Our analyses suggest the thick absorbing envelope to exist in the SS 433 system. Based on our results, we discuss the possible acceleration mechanism for the SS 433 jets.Comment: 15 pages. Accepted for publication by Publ. Astron. Soc. Japa

    Observational Properties of Jets in Active Galactic Nuclei

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    Parsec scale jet properties are shortly presented and discussed. Observational data are used to derive constraints on the jet velocity and orientation, the presence of velocity structures, and the connection between the pc and kpc scale. Two peculiar sources with limb-brightened jets: 1144+35 and Mkn 501 are discussed in detail.Comment: 13 pages with 7 figures. To appear in "Virtual Astrophysical Jets" APSS, Kluwer Academic Publisher - Massaglia, Bodo, Rossi eds - in pres

    Sources of Relativistic Jets in the Galaxy

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    Black holes of stellar mass and neutron stars in binary systems are first detected as hard X-ray sources using high-energy space telescopes. Relativistic jets in some of these compact sources are found by means of multiwavelength observations with ground-based telescopes. The X-ray emission probes the inner accretion disk and immediate surroundings of the compact object, whereas the synchrotron emission from the jets is observed in the radio and infrared bands, and in the future could be detected at even shorter wavelengths. Black-hole X-ray binaries with relativistic jets mimic, on a much smaller scale, many of the phenomena seen in quasars and are thus called microquasars. Because of their proximity, their study opens the way for a better understanding of the relativistic jets seen elsewhere in the Universe. From the observation of two-sided moving jets it is inferred that the ejecta in microquasars move with relativistic speeds similar to those believed to be present in quasars. The simultaneous multiwavelength approach to microquasars reveals in short timescales the close connection between instabilities in the accretion disk seen in the X-rays, and the ejection of relativistic clouds of plasma observed as synchrotron emission at longer wavelengths. Besides contributing to a deeper comprehension of accretion disks and jets, microquasars may serve in the future to determine the distances of jet sources using constraints from special relativity, and the spin of black holes using general relativity.Comment: 39 pages, Tex, 8 figures, to appear in vol. 37 (1999) of Annual Reviews of Astronomy and Astrophysic

    Patients’ Perceptions of Memory Functioning Before and After Surgical Intervention to Treat Medically Refractory Epilepsy.

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    Purpose:One risk associated with epilepsy surgery is memory loss, but perhaps more important is how patients perceive changes in their memories. This longitudinal study evaluated changes in memory self-reports and investigated how self-reports relate to changes on objective memory measures in temporal or extratemporal epilepsy patients who underwent surgery. Methods: Objective memory (Wechsler Memory Scale–Revised) and subjective memory self-reports (Memory Assessment Clinics Self-Rating Scale) were individually assessed for 136 patients ∼6 months before and 6 months after surgery. A measure of depressive affect (Beck Depression Inventory–2nd Edition) was used to control variance attributable to emotional distress. Results: Despite a lack of significant correlational relationships between objective and subjective memory for the entire sample, significant correlations between objective memory scores and self-reports did emerge for a subset of patients who evidenced memory decline. Differences also were found in the subjective memory ratings of temporal lobe versus extratemporal patients. Temporal lobe patients rated their memories more negatively than did extratemporal patients and were more likely to report significant improvements in their memory after surgery. Conclusions: In general, patients were not accurate when rating their memories compared to other adults. However, patients with significant declines in their memories were sensitive to actual changes in their memories over time relative to their own personal baselines

    The monobloc hydrogel breast implant, experiences and ideas

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    This study is focused on the properties of the monobloc hydrogel (MH) breast implant, which has been around for more than 30 years, and to see how it behaves with regard to health complaints as sometimes seen in some patients who had received silicone gel (SG) breast implants. Patients responded to a questionnaire examining their experience with breast implants. Three groups were included. First, the control group (n = 34) of women without breast implants. Second, a C group of women (n = 42) who began and remained on the MH implant. Third, the B group of women who had their silicone gel implant replaced by the MH implant. In the B1 subgroup (n = 22), a capsulectomy was also performed. In the B2 subgroup (n = 13), the replacement was carried out without a capsulectomy. The C group behaved very much like the control group. The women of the B group experienced an improvement of their complaints and the improvement was even better after a capsulectomy. The only difference between the MH and SG implants is the content of the implant. The satisfaction of women with MH implants is generally high and not or hardly associated with health complaints. In women with SG implants and health complaints, these complaints can be relieved by replacement of the implants by MH implants

    Distinct Mechanisms for Induction and Tolerance Regulate the Immediate Early Genes Encoding Interleukin 1β and Tumor Necrosis Factor α

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    Interleukin-1β and Tumor Necrosis Factor α play related, but distinct, roles in immunity and disease. Our study revealed major mechanistic distinctions in the Toll-like receptor (TLR) signaling-dependent induction for the rapidly expressed genes (IL1B and TNF) coding for these two cytokines. Prior to induction, TNF exhibited pre-bound TATA Binding Protein (TBP) and paused RNA Polymerase II (Pol II), hallmarks of poised immediate-early (IE) genes. In contrast, unstimulated IL1B displayed very low levels of both TBP and paused Pol II, requiring the lineage-specific Spi-1/PU.1 (Spi1) transcription factor as an anchor for induction-dependent interaction with two TLR-activated transcription factors, C/EBPβ and NF-κB. Activation and DNA binding of these two pre-expressed factors resulted in de novo recruitment of TBP and Pol II to IL1B in concert with a permissive state for elongation mediated by the recruitment of elongation factor P-TEFb. This Spi1-dependent mechanism for IL1B transcription, which is unique for a rapidly-induced/poised IE gene, was more dependent upon P-TEFb than was the case for the TNF gene. Furthermore, the dependence on phosphoinositide 3-kinase for P-TEFb recruitment to IL1B paralleled a greater sensitivity to the metabolic state of the cell and a lower sensitivity to the phenomenon of endotoxin tolerance than was evident for TNF. Such differences in induction mechanisms argue against the prevailing paradigm that all IE genes possess paused Pol II and may further delineate the specific roles played by each of these rapidly expressed immune modulators. © 2013 Adamik et al

    Massively parallel reporter assays of melanoma risk variants identify MX2 as a gene promoting melanoma

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    Genome-wide association studies (GWAS) have identified ~20 melanoma susceptibility loci, most of which are not functionally characterized. Here we report an approach integrating massively-parallel reporter assays (MPRA) with cell-type-specific epigenome and expression quantitative trait loci (eQTL) to identify susceptibility genes/variants from multiple GWAS loci. From 832 high-LD variants, we identify 39 candidate functional variants from 14 loci displaying allelic transcriptional activity, a subset of which corroborates four colocalizing melanocyte cis-eQTL genes. Among these, we further characterize the locus encompassing the HIV-1 restriction gene, MX2 (Chr21q22.3), and validate a functional intronic variant, rs398206. rs398206 mediates the binding of the transcription factor, YY1, to increase MX2 levels, consistent with the cis-eQTL of MX2 in primary human melanocytes. Melanocyte-specific expression of human MX2 in a zebrafish model demonstrates accelerated melanoma formation in a BRAFV600E background. Our integrative approach streamlines GWAS follow-up studies and highlights a pleiotropic function of MX2 in melanoma susceptibility

    Testosterone Is Associated with Erectile Dysfunction: A Cross-Sectional Study in Chinese Men

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    Testosterone is essential for the regulation of erectile physiology, but the relationship between low testosterone and erectile dysfunction (ED) has not been firmly established.To examine the association between serum total, free and bio-available testosterone and ED in a population-based sample.A consecutive series of 1776 men aged 20–77 participated in the routine physical examination from September 2009 to December 2009 in Guangxi, China. ED was assessed using the five-item International Index of Erectile Function (IIEF-5) questionnaire. Total testosterone (TT), sex hormone binding globulin (SHBG) and other biochemical profiles were measured. Free testosterone (FT) and bio-available testosterone (BT) were calculated based on Vermeulen’s formula. Data were collected with regard to smoking, alcoholic drinking, physical activity and metabolic syndrome.The prevalence of ED (IIEF-5<22) was 47.6%. Men with ED were significantly older, and more prone to smoke cigarettes (≥20 cigarettes/day) or drink alcohol (≥3 drinks/week), and more likely to have elevated blood pressure (P = 0.036) or hyperglycemia (P<0.001) compared with those without ED. The significant increase in SHBG with age was parallel to its increase with increasing severity of ED (P<0.001). The obscure increase in TT across the ED status was detected without significance (P = 0.418), but TT was positively associated with ED after adjustment for age [odds ratio (OR)  = 1.02, 95% CI (confidence internal): 1.00–1.04]. FT and BT were inversely associated with ED (OR = 0.14, 95%CI: 0.06–0.33; OR = 0.92 (95%CI: 0.89–0.96, respectively) in the univariate analysis, and this inverse association appeared to be independent of smoking status, alcoholic drinking, physical activity, hyper-triglyceridemia and hyperglycemia.FT and BT are inversely related to worsening ED, whereas the positive association between TT and ED is most likely due to the increase in SHBG

    Tumoral CD105 is a novel independent prognostic marker for prognosis in clear-cell renal cell carcinoma

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    International audienceBackground: Angiogenesis is essential for tumour growth and metastasis. There are conflicting reports as to whether microvessel density (MVD) using the endothelial marker CD105 (cluster of differentiation molecule 105) in clear-cell renal cell carcinomas (ccRCC) is associated with prognosis. Recently, CD105 has been described as a RCC cancer stem cell marker.Methods: A total of 102 ccRCC were analysed. Representative tumour sections were stained for CD105. Vascularity (endothelial CD105) was quantified by MVD. The immunohistochemistry analysis detected positive (if present) or negative (if absent) CD105 tumoral staining. This retrospective population-based study was evaluated using Kaplan–Meier method, t-test and Cox proportional hazard model.Results: We found that the expression of endothelial CD105 (MVD) negatively correlated with nuclear grade (P<0.001), tumour stage (P<0.001) and Leibovitch score (P<0.001), whereas the expression of tumoral CD105 positively correlated with these three clinicopathological factors (P<0.001). In multivariate analysis, tumoral CD105 was found to be an independent predictor of poor overall survival (P=0.002).Conclusions: We have shown for the first time that tumoral CD105 is an independent predictive marker for death risk and unfavourable prognosis in patients with ccRCC after curative resection

    Prognostic analysis of tumour angiogenesis, determined by microvessel density and expression of vascular endothelial growth factor, in high-risk primary breast cancer patients treated with high-dose chemotherapy

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    In contrast to early breast cancer, the prognostic effect of tumour angiogenesis in tumours with advanced axillary spread has been less studied. We retrospectively analysed the effect of microvessel density (MVD) and vascular endothelial growth factor (VEGF) by immunohistochemistry on the outcome of 215 patients treated uniformly within prospective trials of high-dose chemotherapy for 4–9 and ⩾10 positive nodes, and followed for a median of 9 (range 3–13) years. Microvessel density was associated with epidermal growth factor receptor (EGFR) expression (P<0.001) and tumour size (P=0.001). Vascular endothelial growth factor overexpression (51% of patients) was associated with overexpression of EGFR (P=0.01) and HER2 (P<0.05), but not with MVD (P=0.3). High MVD was associated with worse relapse-free survival (74 vs 44%, P<0.001) and overall survival (76 vs 44%, P<0.001). Vascular endothelial growth factor overexpression had no effect on outcome. Multivariate analyses showed a prognostic effect of MVD independently of other known prognostic factors in this patient population. In conclusion, tumour angiogenesis, expressed as MVD, is a major independent prognostic factor in breast cancer patients with extensive axillary involvement
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