49 research outputs found

    Free flux flow resistivity in strongly overdoped high-T_c cuprate; purely viscous motion of the vortices in semiclassical d-wave superconductor

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    We report the free flux flow (FFF) resistivity associated with a purely viscous motion of the vortices in moderately clean d-wave superconductor Bi:2201 in the strongly overdoped regime (T_c=16K) for a wide range of the magnetic field in the vortex state. The FFF resistivity is obtained by measuring the microwave surface impedance at different microwave frequencies. It is found that the FFF resistivity is remarkably different from that of conventional s-wave superconductors. At low fields (H<0.2H_c2) the FFF resistivity increases linearly with H with a coefficient which is far larger than that found in conventional s-wave superconductors. At higher fields, the FFF resistivity increases in proportion to \sqrt H up to H_c2. Based on these results, the energy dissipation mechanism associated with the viscous vortex motion in "semiclassical" d-wave superconductors with gap nodes is discussed. Two possible scenarios are put forth for these field dependence; the enhancement of the quasiparticle relaxation rate and the reduction of the number of the quasiparticles participating the energy dissipation in d-wave vortex state.Comment: 9 pages 7 figures, to appear in Phys. Rev.

    A physical analysis of the Y chromosome shows no additional deletions, other than Gr/Gr, associated with testicular germ cell tumour

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    Testicular germ cell tumour (TGCT) is the most common malignancy in men aged 15–45 years. A small deletion on the Y chromosome known as ‘gr/gr' was shown to be associated with a two-fold increased risk of TGCT, increasing to three-fold in cases with a family history of TGCT. Additional deletions of the Y chromosome, known as AZFa, AZFb and AZFc, are described in patients with infertility; however, complete deletions of these regions have not been identified in TGCT patients. We screened the Y chromosome in a series of TGCT cases to evaluate if additional deletions of Y were implicated in TGCT susceptibility. Single copy Y chromosome STS markers with an average inter-marker spacing of 128 kb were examined in constitutional DNA of 271 index TGCT patients. Three markers showed evidence of deletions, sY1291, indicative of ‘gr/gr' (eight out of 271; 2.9%), Y-DAZ3 contained within ‘gr/gr' (21 out of 271; 7.7%) and a single deletion of the marker G66152 was identified in one TGCT case. No other markers demonstrated deletions. While several regions of the Y chromosome are known to be deleted and associated with infertility, our study provides no evidence to suggest regions of Y deletion, other than ‘gr/gr', are associated with susceptibility to TGCT in UK patients

    The potential protective effects of pre-injury exercise on neuroimmune responses following experimentally-induced traumatic neuropathy: a systematic review with meta-analysis

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    Pre-clinical evidence shows that neuropathy is associated with complex neuroimmune responses, which in turn are associated with increased intensity and persistence of neuropathic pain. Routine exercise has the potential to mitigate complications of future nerve damage and persistence of pain through neuroimmune regulation. This systematic review aimed to explore the effect of pre-injury exercise on neuroimmune responses, and other physiological and behavioural reactions following peripheral neuropathy in animals. Three electronic databases were searched from inception to July 2022. All controlled animal studies assessing the influence of an active exercise program prior to experimentally-induced traumatic peripheral neuropathy compared to a non-exercise control group on neuroimmune, physiological and behavioural outcomes were selected. The search identified 17,431 records. After screening, 11 articles were included. Meta-analyses showed that pre-injury exercise significantly reduced levels of IL-1β (SMD: -1.06, 95% CI: -1.99 to -0.13, n=40), but not iNOS (SMD: -0.71 95% CI: -1.66 to 0.25, n=82). From 72 comparisons of different neuroimmune outcomes at different anatomical locations, vote counting revealed reductions in 23 pro-inflammatory and increases in 6 anti-inflammatory neuroimmune outcomes. For physiological outcomes, meta-analyses revealed that pre-injury exercise improved one out of six nerve morphometric related outcomes (G-ratio; SMD: 1.95, 95%CI: 0.77 to 3.12, n=20) and one out of two muscle morphometric outcomes (muscle fibre cross-sectional area; SMD: 0.91, 95%CI: 0.27 to 1.54, n=48). For behavioural outcomes, mechanical allodynia was significantly less in the pre-injury exercise group (SMD -1.24, 95%CI: -1.87 to -0.61) whereas no overall effect was seen for sciatic function index. Post hoc subgroup analysis suggests that timing of outcome measurement may influence the effect of pre-injury exercise on mechanical allodynia. Risk of bias was unclear in most studies, as the design and conduct of the included experiments were poorly reported. Preventative exercise may have potential neuroprotective and immunoregulatory effects limiting the sequalae of nerve injury, but more research in this field is urgently needed
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