49 research outputs found

    Significance of CO2/CO ratio in dissolved gas analysis

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    According to the literature, the ratio of carbon dioxide and carbon monoxide (CO2/CO) for a transformer with a healthy cellulose insulation system should be between 3 and 11. If results of the dissolved gas analysis (DGA) of oil from transformers in service give the ratio value of CO2/CO less than 3, it means that the cellulose insulation is degrading rapidly. What is the meaning of this ratio if it is high; say greater than 15 or 20

    Role of the cluster structure of 7^7Li in the dynamics of fragment capture

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    Exclusive measurements of prompt γ\gamma-rays from the heavy-residues with various light charged particles in the 7^7Li + 198^{198}Pt system, at an energy near the Coulomb barrier (E/VbV_b \sim 1.6) are reported. Recent dynamic classical trajectory calculations, constrained by the measured fusion, α\alpha and tt capture cross-sections have been used to explain the excitation energy dependence of the residue cross-sections. These calculations distinctly illustrate a two step process, breakup followed by fusion in case of the capture of tt and α\alpha clusters; whereas for 6^{6}He + pp and 5^{5}He + dd configurations, massive transfer is inferred to be the dominant mechanism. The present work clearly demonstrates the role played by the cluster structures of 7^7Li in understanding the reaction dynamics at energies around the Coulomb barrier.Comment: 6 pages, 4 figures, Accepted for publication in Phys. Letts.

    Evidence for transfer followed by breakup in 7Li + 65Cu

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    The observation of a large cross-section for the alpha + d channel compared to breakup into the alpha + t channel from an exclusive measurement for the 7Li+65Cu system at 25 MeV is presented. A detailed analysis of the angular distribution using coupled channels Born approximation calculations has provided clear evidence that the observed alpha + d events arise from a two step process, i.e. direct transfer to the 2.186 MeV (3+) resonance in the alpha + d continuum of 6Li followed by breakup, and are not due to final state interaction effects.Comment: 12 pages, 3 figures, To be published in Phys. Letts.

    Exploring fusion at extreme sub barrier energies with weakly bound nuclei

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    Accepted for publication in Physical Review LettersResults of measurement of residues formed in fusion of 6Li with 198Pt in the energy range of 0.68< E/VbV_b <1.3 using a new sensitive off-beam technique are reported. The fusion excitation function and the derived average angular momenta do not indicate a change of slope at deep sub-barrier energies, contrary to recent observations. The present results for a system with weakly bound projectile confront the current understanding of the fusion hindrance at these low energies, underlying the role of internal re-organization on the dynamical path towards fusion

    Direct evidence of transfer with weakly bound isotopes of He near the Coulomb barrier and implications of fusion

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    NESTERPartial residue cross sections for fusion and transfer have been measured from the intensities of characteristic gamma-rays for the 4,6^{4,6} He + 63,65^{63,65}Cu systems at energies near the Coulomb barrier (Vb)

    The PICTURE study: diagnostic accuracy of multiparametric MRI in men requiring a repeat prostate biopsy.

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    BACKGROUND: Transrectal prostate biopsy has limited diagnostic accuracy. Prostate Imaging Compared to Transperineal Ultrasound-guided biopsy for significant prostate cancer Risk Evaluation (PICTURE) was a paired-cohort confirmatory study designed to assess diagnostic accuracy of multiparametric magnetic resonance imaging (mpMRI) in men requiring a repeat biopsy. METHODS: All underwent 3 T mpMRI and transperineal template prostate mapping biopsies (TTPM biopsies). Multiparametric MRI was reported using Likert scores and radiologists were blinded to initial biopsies. Men were blinded to mpMRI results. Clinically significant prostate cancer was defined as Gleason ⩾4+3 and/or cancer core length ⩾6 mm. RESULTS: Two hundred and forty-nine had both tests with mean (s.d.) age was 62 (7) years, median (IQR) PSA 6.8 ng ml (4.98-9.50), median (IQR) number of previous biopsies 1 (1-2) and mean (s.d.) gland size 37 ml (15.5). On TTPM biopsies, 103 (41%) had clinically significant prostate cancer. Two hundred and fourteen (86%) had a positive prostate mpMRI using Likert score ⩾3; sensitivity was 97.1% (95% confidence interval (CI): 92-99), specificity 21.9% (15.5-29.5), negative predictive value (NPV) 91.4% (76.9-98.1) and positive predictive value (PPV) 46.7% (35.2-47.8). One hundred and twenty-nine (51.8%) had a positive mpMRI using Likert score ⩾4; sensitivity was 80.6% (71.6-87.7), specificity 68.5% (60.3-75.9), NPV 83.3% (75.4-89.5) and PPV 64.3% (55.4-72.6). CONCLUSIONS: In men advised to have a repeat prostate biopsy, prostate mpMRI could be used to safely avoid a repeat biopsy with high sensitivity for clinically significant cancers. However, such a strategy can miss some significant cancers and overdiagnose insignificant cancers depending on the mpMRI score threshold used to define which men should be biopsied

    1n- and 2n-transfer with the Borromean nucleus 6^{6}He near the Coulomb barrier

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    Accepetd for publication in Physical Review LettersAngular distributions for 1n- and 2n-transfer are reported for the 6He + 65Cu system at Elab = 22.6 MeV. For the first time, triple coincidences between particles, neutrons and characteristic rays from the target-like residues were used to separate the contributions arising from 1n- and 2n-transfer. The differential cross sections for these channels, elastic scattering, and fusion were analyzed using a Coupled Reaction Channels approach. The large measured ratio of the 2n/1n cross section and the strong influence of 2n-transfer on other channels indicate that the di-neutron configuration of 6He plays a dominant role in the reaction mechanism

    Cardiovascular Risk Factors Are Associated With Future Cancer

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    BACKGROUND The extent to which co-occurrence of cardiovascular disease (CVD) and cancer is due to shared risk factors or other mechanisms is unknown. OBJECTIVES This study investigated the association of standard CVD risk factors, CVD biomarkers, pre-existing CVD, and ideal cardiovascular (CV) health metrics with the development of future cancer. METHODS This study prospectively followed Framingham Heart Study and PREVEND (Prevention of Renal and Vascular End-Stage Disease) study participants free of cancer at baseline and ascertained histology-proven cancer. This study assessed the association of baseline CV risk factors, 10-year atherosclerotic (ASCVD) risk score, established CVD biomarkers, prevalent CVD, and the American Heart Association (AHA) Life's Simple 7 CV health score with incident cancer using multivariable Cox models. Analyses of interim CVD events with incident cancer used time-dependent covariates. RESULTS Among 20,305 participants (mean age 50 +/- 14 years; 54% women), 2,548 incident cancer cases occurred over a median follow-up of 15.0 years (quartile 1 to 3: 13.3 to 15.0 years). Traditional CVD risk factors, including age, sex, and smoking status, were independently associated with cancer (p < 0.001 for all). Estimated 10-year ASCVD risk was also associated with future cancer (hazard ratio [HR]: 1.16 per 5% increase in risk; 95% confidence interval [CI] 1.14 to 1.17; p < 0.001). The study found that natriuretic peptides (tertile 3 vs. tertite 1; HR: 1.40; 95% 0:1.03 to 1.91; p 0.035) were associated with incident cancer but not high-sensitivity troponin (p 0.47). Prevalent CVD and the development of interim CV events were not associated with higher risk of subsequent cancer. However, ideal CV health was associated with tower future cancer risk (HR: 0.95 per 1-point increase in the AHA health score; 95% CI: 0.92 to 0.99; p = 0.009). CONCLUSIONS CVD risk, as captured by traditional CVD risk factors, 10-year ASCVD risk score, and natriuretic peptide concentrations are associated with increased risk of future cancer. Conversely, a heart healthy lifestyle is associated with a lower risk of future cancer. These data suggest that the association between CVD and future cancer is attributable to shared risk factors. (C) 2021 The Authors. Published by Elsevier on behalf of the American College of Cardiology Foundation

    Prevalence, awareness and control of hypertension in Malaysia from 1980-2018: a systematic review and meta-analysis

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    Background: Hypertension is a common public health problem worldwide and is a well-known risk factor for increased risk of cardiovascular diseases, contributing to high morbidity and mortality. However, there has been no systematic review and meta-analysis of a multiethnic population such as that of Malaysia. Aim: To determine the trend in prevalence, awareness and control rate of hypertension in Malaysia. Methods: Systematic searches were conducted in six databases (PubMed, Scopus, Ovid, CINAHL, Malaysian Medical Repository and Malaysia Citation Index) for articles published between 1980 and 2018. Two authors reviewed the studies and performed quality assessment and data extraction independently. Pooled estimates of hypertension prevalence, awareness and control rate were calculated using the DerSimonian-Laird random-effects model. Subgroup and sensitivity analyses were performed. Results: We included 56 studies involving a total of 241796 participants. The overall pooled prevalence of hypertension aged ≥ 18 years was 29.7%. The prevalence of hypertension was the lowest in the 1980s (16.2%, 95% confidence interval (CI): 13.4, 19.0), increasing up to 36.8% (95%CI: 6.1, 67.5) in the 1990s, then decreasing to 28.7% (95%CI: 21.7, 35.8) in the 2000s and 26.8% (95%CI: 21.3, 32.3) in the 2010s. The prevalence of awareness was 51.4% (95%CI: 46.6, 56.3), while 33.3% (95%CI: 28.4, 38.2) of those on treatment had achieved control of their blood pressure. Conclusion: In Malaysia, three in ten adults aged ≥ 18 years have hypertension, while four in ten adults aged ≥ 30 years have hypertension. Five out of ten people are aware of their hypertension status and only one-third of those under treatment achieved control of their hypertension. Concerted efforts by policymakers and healthcare professionals to improve awareness and control of hypertension should be of high priority
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