289 research outputs found

    Magnetic resonance peak and nonmagnetic impurities

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    Nonmagnetic Zn impurities are known to strongly suppress superconductivity. We review their effects on the spin excitation spectrum in YBa2Cu3O7\rm YBa_2Cu_3O_{7}, as investigated by inelastic neutron scattering measurements.Comment: Proceedings of Mato Advanced Research Workshop BLED 2000. To appear in Nato Science Series: B Physic

    A five-year retrospective study of the epidemiological characteristics and visual outcomes of patients hospitalized for ocular trauma in a Mediterranean area

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    <p>Abstract</p> <p>Background</p> <p>To determine the epidemiological characteristics and visual outcome of ocular trauma in southern Italy.</p> <p>Methods</p> <p>All cases of ocular trauma admitted to Department of Ophthalmology of Palermo University, Italy, from January 2001–December 2005 were retrospectively reviewed for open- or closed-globe injury (OGI or CGI). Data extracted included age, sex, residence, initial and final visual acuity (VA), cause and treatment of injury, hospitalization. The injuries were classified by Ocular Trauma Classification System (OTCS) and Birmingham Eye Trauma Terminology (BETT). We also referred to the Ocular Trauma Score (OTS) in evaluating the final visual outcome.</p> <p>Results</p> <p>Of the 298 eyes, there were 146 OGI and 152 CGI. Fifty eyes (16.8%) had an intraocular foreign body (IOFB). The annual incidence of eye injuries was 4.9 per 100,000. Most injuries occurred in men (84.6%, p < 0.0005), with an average age of 33.0 vs. 49.9 for women (p = 0.005). Cause of injury differed significantly by gender (p = 0.001) and urban vs. rural location (p = 0.009). The most frequent causes in men were outdoor activities related injuries (30.9%), work-related (25.4%), and sport-related (17.5%), and in women were home-related (52.2%) and outdoor activities related injuries (30.4%). In urban areas, road accidents were more frequent; in rural areas, work-related injuries were more frequent with a greater rate of IOFBs than in urban areas (p = 0.002).</p> <p>The incidence of OGI and CGI differed in work-related injuries (p < 0.0005), sport-related injuries (p < 0.0005), and assaults (p = 0.033). The final visual acuity was 20/40 (6/12) or better in 144 eyes (48.3%), 20/40–20/200 (6/12–6/60) in 90 eyes (30.2%), and <20/200 (6/60) or less in 46 eyes (15.5%). Eighteen eyes (6%) had a final acuity of no light perception. Of those eyes that presented with hand motion vision or better, 220 (86.6%) had a final vision of better than 20/200 (6/60). Initial visual acuity was found to be correlated with final visual acuity (Spearman's correlation coefficient = 0.658; p < 0.001). The likelihood of the final visual acuities in the OTS categories was correlated to that of the OTS study group in 12 of 14 cases (85.7%).</p> <p>Conclusion</p> <p>This analysis provides insight into the epidemiology of patients hospitalized for ocular trauma. The findings indicate that ocular trauma is a significant cause of visual loss in this population.</p

    The Angio-Fibrotic Switch of VEGF and CTGF in Proliferative Diabetic Retinopathy

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    BACKGROUND: In proliferative diabetic retinopathy (PDR), vascular endothelial growth factor (VEGF) and connective tissue growth factor (CTGF) cause blindness by neovascularization and subsequent fibrosis, but their relative contribution to both processes is unknown. We hypothesize that the balance between levels of pro-angiogenic VEGF and pro-fibrotic CTGF regulates angiogenesis, the angio-fibrotic switch, and the resulting fibrosis and scarring. METHODS/PRINCIPAL FINDINGS: VEGF and CTGF were measured by ELISA in 68 vitreous samples of patients with proliferative DR (PDR, N = 32), macular hole (N = 13) or macular pucker (N = 23) and were related to clinical data, including degree of intra-ocular neovascularization and fibrosis. In addition, clinical cases of PDR (n = 4) were studied before and after pan-retinal photocoagulation and intra-vitreal injections with bevacizumab, an antibody against VEGF. Neovascularization and fibrosis in various degrees occurred almost exclusively in PDR patients. In PDR patients, vitreous CTGF levels were significantly associated with degree of fibrosis and with VEGF levels, but not with neovascularization, whereas VEGF levels were associated only with neovascularization. The ratio of CTGF and VEGF was the strongest predictor of degree of fibrosis. As predicted by these findings, patients with PDR demonstrated a temporary increase in intra-ocular fibrosis after anti-VEGF treatment or laser treatment. CONCLUSIONS/SIGNIFICANCE: CTGF is primarily a pro-fibrotic factor in the eye, and a shift in the balance between CTGF and VEGF is associated with the switch from angiogenesis to fibrosis in proliferative retinopathy

    Advances in using PARP inhibitors to treat cancer

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    The poly (ADP-ribose) polymerase (PARP) family of enzymes plays a critical role in the maintenance of DNA integrity as part of the base excision pathway of DNA repair. PARP1 is overexpressed in a variety of cancers, and its expression has been associated with overall prognosis in cancer, especially breast cancer. A series of new therapeutic agents that are potent inhibitors of the PARP1 and PARP2 isoforms have demonstrated important clinical activity in patients with breast or ovarian cancers that are caused by mutations in either the BRCA1 or 2 genes. Results from such studies may define a new therapeutic paradigm, wherein simultaneous loss of the capacity to repair DNA damage may have antitumor activity in itself, as well as enhance the antineoplastic potential of cytotoxic chemotherapeutic agents

    The Evolution of Compact Binary Star Systems

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    We review the formation and evolution of compact binary stars consisting of white dwarfs (WDs), neutron stars (NSs), and black holes (BHs). Binary NSs and BHs are thought to be the primary astrophysical sources of gravitational waves (GWs) within the frequency band of ground-based detectors, while compact binaries of WDs are important sources of GWs at lower frequencies to be covered by space interferometers (LISA). Major uncertainties in the current understanding of properties of NSs and BHs most relevant to the GW studies are discussed, including the treatment of the natal kicks which compact stellar remnants acquire during the core collapse of massive stars and the common envelope phase of binary evolution. We discuss the coalescence rates of binary NSs and BHs and prospects for their detections, the formation and evolution of binary WDs and their observational manifestations. Special attention is given to AM CVn-stars -- compact binaries in which the Roche lobe is filled by another WD or a low-mass partially degenerate helium-star, as these stars are thought to be the best LISA verification binary GW sources.Comment: 105 pages, 18 figure

    A Phase I study of the angiogenesis inhibitor SU5416 (semaxanib) in solid tumours, incorporating dynamic contrast MR pharmacodynamic end points

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    SU5416 (Z-3-[(2,4-dimethylpyrrol-5-yl)methylidenyl]-2-indolinone; semaxanib) is a small molecule inhibitor of the vascular endothelial growth factor receptor (VEGFR)2. A Phase I dose escalation study was performed. Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) was used as a pharmacodynamic assessment tool. In all, 27 patients were recruited. SU5416 was administered twice weekly by fixed rate intravenous infusion. Patients were treated in sequential cohorts of three patients at 48, 65, 85 110 and 145 mg m−2. A further dose level of 190 mg m−2 after a 2-week lead in period at a lower dose was completed; thereafter, the cohort at 145 mg m−2 was expanded. SU5416 showed linear pharmacokinetics to 145 mg m−2 with a large volume of distribution and rapid clearance. A significant degree of interpatient variability was seen. SU5416 was well tolerated, by definition a maximum-tolerated dose was not defined. No reproducible changes were seen in DCE-MRI end points. Serial assessments of VEGF in a cohort of patients treated at 145 mg m−2 did not show a statistically significant treatment-related change. Parallel assessments of the impact of SU5416 on coagulation profiles in six patients showed a transient effect within the fibrinolytic pathway. Clinical experience showed that patients who had breaks of therapy longer than a week could not have treatment reinitiated at a dose of 190 mg m−2 without unacceptable toxicity. The 145 mg m−2 dose level is thus the recommended dose for future study
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