SHRIMP U-Pb ages of the Karasaki mylonites in western Shikoku, Japan

唐崎マイロナイトの優白質角閃岩マイロナイトについて, ジルコンのSHRIMP U-Pb年代測定を行った結果, 1試料からの8粒子は114.2±3.9～102.3±4.5Ma(±1σ)の年代値を示した.マイロナイト化した優白質角閃岩は, SiO_2含有量が低い(49wt.%)ことと, 主として角閃石, 曹長石, 緑泥石および緑簾石のモード比の違いによる数百μm～数mm幅の顕著な層状構造を有することから, 玄武岩質火山岩または火山砕屑岩に由来する砂岩を原岩としている可能性が高い.優白質角閃岩マイロナイト中の丸みを帯びたジルコンは, ある程度遠方より運搬される過程で円磨された可能性が高いこと, マグマから晶出したジルコンに特徴的なオシレトリー累帯構造が認められることから, 砕屑性起源のジルコンであると判断される.また, その年代値が約110Maの狭い範囲を示す事実は, ジルコンが"古領家帯"に帰属すると考えられる真穴帯の大島変成岩や肥後帯の約110Ma深成岩類のみに由来する可能性を示唆する.したがって, 本論において初めて"古領家帯"中にアルビアン以降の堆積岩源変成岩が存在していることが明らかとなった.Zircon U-Pb isotope ages have been analyzed by the Sensitive High Resolution Ion MicroProbe (SHRIMP) in an leucocratic amphibolite mylonite from the Karasaki mylonites, western Shikoku, Japan which has been considered to belong to the "Paleo-Ryoke" belt. Eight zircon grains from the sample yielded U-Pb ages of Albian (Early Cretaceous) ranging from 114.2 ± 3.9 Ma to 102.3 ±4.5 Ma (± 1σ errors). The protolith of the mylonitized leucocratic amphibolite has been inferred to be basaltic volcanic sandstones, because the SiO_2 content is low (49 wt.%), and the leucocratic amphibolite (consisting of albite and epidote rich, and chlorite and epidote rich layers alternates with amphibole rich and chlorite rich layers on the order of a few mm, suggestive of original sedimentary layering. All the zircon grains can be inferred to be detrital based on both the facts that they were abraded possibly due to sedimentation processes, and that they show oscillatory zoning indicating igneous (primary) texture. The small range of U-Pb ages varying ca. 110 Ma suggests that the zircon grains in the volcanic sandstones were supplied only from the Oshima metamorphic rocks of the Maana belt and the Higo plutonic rocks of the Higo belt whose U-Pb zircon ages were dated as ca. 110 Ma. The fact clearly indicates that the metamorphic rocks (Karasaki mylonites) originated from post-Albian sediments also constitute as a new member of the "Paleo-Ryoke" belt

The nuclear interaction at Oklo 2 billion years ago

We re-examine the effort to constrain the time-variability of the coupling constants of the fundamental interactions by studying the anomalous isotopic abundance of Sm observed at the remnants of the natural reactors which were in operation at Oklo about 2 billion years ago, in terms of a possible deviation of the resonance energy from the value observed today. We rely on new samples that were carefully collected to minimize natural contamination and also on a careful temperature estimate of the reactors. We obtain the upper bound $(-0.2\pm 0.8)\times 10^{-17}$ ${\rm y}^{-1}$ on the fractional rate of change of the electromagnetic as well as the strong interaction coupling constants. Our result basically agrees with and even suggests some improvement of the result due recently to Damour and Dyson. Strictly speaking, however, we find another range of the resonance energy shift indicating a nonzero time variation of the constants. We find a rather strong but still tentative indication that this range can be ruled out by including the Gd data, for which it is essential to take the effect of contamination into account.Comment: 20 pages LaTex including 6 figures. Theoretical interpretation changed. More detailed discussions on the temperature estimate also adde

Light Scalar Top and Heavy Top Signature at CDF

We propose a mechanism which could explain a slight excess of top signal rate recently reported by CDF in the framework of the supersymmetric standard model. If the scalar partner of the top (stop) is sufficiently light, the gluino with an appropriate mass could decay into the stop plus the top with almost 100\% branching ratio and experimental signatures of the gluino pair production could be indistinguishable from those of the top production in the present integrated luminosity Tevatron running. In this case the standard top signal, $W$ $+$ multi-jets events, would be effectively enhanced by the additional gluino contribution. It is shown, moreover, that such a mechanism can actually work in the radiative SU(2)$\times$U(1) breaking model without the GUT relations between the gaugino mass parameters.Comment: 8 pages (LaTeX), 3 figures not included (available on request) ; ITP-SU-94/03, RUP-94-0

Substance use and sexual behaviours of Japanese men who have sex with men: A nationwide internet survey conducted in Japan

BACKGROUND: Japanese men who have sex with men (MSM), especially those living in large metropolitan areas such as Tokyo and Osaka, are facing a growing HIV/AIDS epidemic. Although the Internet is used as a new venue for meeting sex partners, it can also serve as a useful research tool for investigating the risk behaviours of Japanese MSM. This Internet survey explored the extent of substance use and its association with sexual risk behaviours among Japanese MSM. METHODS: Between 28 February 2003 and 16 May 2003 MSM were recruited through 57 Japanese gay-oriented Web sites, gay magazines, and Internet mailing lists. Participants completed a structured questionnaire anonymously through the Internet. RESULTS: In total, 2,062 Japanese MSM completed the questionnaire. The average age of participants was 29.0 years and 70.5% identified as gay, 20.8% as bisexual, and 8.7% as other. Overall, 34.5% reported never using a substance, 45% reported ever using one type of substance (lifetime reported single substance users), and 19.6% had used more than 1 type of substance (lifetime reported multiple substance users) in their lifetimes. The substances most commonly used were amyl nitrite (63.2%), 5-methoxy-N, N-diisopropyltryptamine (5MEO-DIPT) (9.3%), and marijuana (5.7%). In the multivariate analysis, unprotected anal intercourse, having had 6 or more sexual partners, visiting a sex club/gay venue in the previous 6 months, a lower education level, and being 30 to 39 years of age were associated with both lifetime single and lifetime multiple substance use. Lifetime reported multiple substance use was also correlated with having a casual sex partner, having symptoms of depression, being diagnosed as HIV-positive, and greater HIV/AIDS-related knowledge. CONCLUSION: This is the first Internet-based research focused on the sexual and substance use behaviours of MSM in Asia. Our findings suggest a compelling need for prevention interventions to reduce HIV risk-related substance use behaviours among Japanese MSM. The results also suggest that the Internet is potentially a useful tool for collecting behavioural data and promoting prevention interventions among this population

Utility of a simplified ultrasonography scoring system among patients with rheumatoid arthritis: A multicenter cohort study

ABSTRACT: We aimed to evaluate the utility of a simplified ultrasonography (US) scoring system, which is desired in daily clinical practice, among patients with rheumatoid arthritis (RA) receiving biological/targeted synthetic disease-modifying antirheumatic drugs (DMARDs).A total of 289 Japanese patients with RA who were started on tumor necrosis factor inhibitors, abatacept, tocilizumab, or Janus kinase inhibitors between June 2013 and April 2019 at one of the 15 participating rheumatology centers were reviewed. We performed US assessment of articular synovia over 22 joints among bilateral wrist and finger joints, and the 22-joint (22j)-GS and 22-joint (22j)-PD scores were evaluated as an indicator of US activity using the sum of the GS and PD scores, respectively.The top 6 most affected joints included the bilateral wrist and second/third metacarpophalangeal joints. Therefore, 6-joint (6j)-GS and -PD scores were defined as the sum of the GS and PD scores from the 6 synovial sites over the aforementioned 6 joints, respectively. Although the 22j- or 6j-US scores were significantly correlated with DAS28-ESR or -CRP scores, the correlations were weak. Conversely, 6j-US scores were significantly and strongly correlated with 22j-US scores not only at baseline but also after therapy initiation.Using a multicenter cohort data, our results indicated that a simplified US scoring system could be adequately tolerated during any disease course among patients with RA receiving biological/targeted synthetic DMARDs

Changes in TRPV1 Receptor, CGRP, and BDNF Expression in Rat Dorsal Root Ganglion with Resiniferatoxin-Induced Neuropathic Pain: Modulation by Pulsed Radiofrequency Applied to the Sciatic Nerve

Pulsed radiofrequency (PRF) is a safe method of treating neuropathic pain by generating intermittent electric fields at the needle tip. Resiniferatoxin (RTX) is an ultrapotent agonist of transient receptor potential vanilloid subtype-1 (TRPV1) receptors. We investigated the mechanism of PRF using a rat model of RTX-induced neuropathic pain. After administering RTX intraperitoneally, PRF was applied to the right sciatic nerve. We observed the changes in TRPV1, calcitonin gene-related peptide (CGRP), and brain-derived neurotrophic factor (BDNF) in the dorsal root ganglia by western blotting. Expressions of TRPV1 and CGRP were significantly lower in the contralateral (RTX-treated, PRF-untreated) tissue than in control rats (p<0.0001 and p<0.0001, respectively) and the ipsilateral tissues (p<0.0001 and p<0.0001, respectively). BDNF levels were significantly higher in the contralateral tissues than in the control rats (p<0.0001) and the ipsilateral tissues (p<0.0001). These results suggest that, while TRPV1 and CGRP are decreased by RTX-induced neuronal damage, increased BDNF levels result in pain development. PRF may promote recovery from neuronal damage with concomitant restoration of TRPV1 and CGRP, and exert its analgesic effect by reversing BDNF increase. Further research is required to understand the role of TRPV1 and CGRP restoration in improving mechanical allodynia

Factors Associated with Myelosuppression Related to Low-Dose Methotrexate Therapy for Inflammatory Rheumatic Diseases.

OBJECTIVE:Severe myelosuppression is a serious concern in the management of rheumatic disease patients receiving methotrexate (MTX) therapy. This study was intended to explore factors associated with the development of MTX-related myelosuppression and its disease severity. METHODS:We retrospectively examined a total of 40 cases of MTX-related myelosuppression that had been filed in the registries of participating rheumatology and hematology divisions. Data before onset were compared with those of 120 controls matched for age and sex. Cytopenia was graded according to the National Cancer Institute criteria for adverse events. Data before and at onset were compared between the severe and non-severe groups. RESULTS:Non-use of folic acid supplements, concurrent medications, and low renal function were significantly associated with the development of myelosuppression (p < 0.001, p < 0.001, and p = 0.002, respectively). In addition, significantly lower MTX dosages, higher blood cell counts, and lower hemoglobin levels were seen in the myelosuppression group (p < 0.001). No patients exhibited leukocytopenia, neutropenia, or thrombocytopenia in routine blood monitoring taken within the past month. One-fourth developed myelosuppression within the first two months (an early-onset period). Myelosuppression was severe in approximately 40% of patients. Hypoalbuminemia and non-use of folic acid supplements were significantly associated with the severity of pancytopenia (p = 0.001 and 0.008, respectively). Besides these two factors, early onset and the use of lower doses of MTX were significantly associated with the severity of neutropenia (p = 0.003, 0.007, 0.003, and 0.002, respectively). CONCLUSIONS:Myelosuppression can occur abruptly at any time during low-dose MTX therapy, but severe neutropenia is more likely to occur in the early-onset period of this therapy. Contrary to our expectations, disease severity was not dependent on MTX doses. Serum albumin levels and folic acid supplementation are the important factors affecting the severity of MTX-related pancytopenia and neutropenia