248 research outputs found

    Singlet levels of the NV^{-} centre in diamond

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    The characteristic transition of the NV- centre at 637 nm is between 3A2{}^3\mathrm{A}_2 and 3E{}^3\mathrm{E} triplet states. There are also intermediate 1A1{}^1\mathrm{A}_1 and 1E{}^1\mathrm{E} singlet states, and the infrared transition at 1042 nm between these singlets is studied here using uniaxial stress. The stress shift and splitting parameters are determined, and the physical interaction giving rise to the parameters is considered within the accepted electronic model of the centre. It is established that this interaction for the infrared transition is due to a modification of electron-electron Coulomb repulsion interaction. This is in contrast to the visible 637 nm transition where shifts and splittings arise from modification to the one-electron Coulomb interaction. It is also established that a dynamic Jahn-Teller interaction is associated with the singlet 1E{}^1\mathrm{E} state, which gives rise to a vibronic level 115 cm1\mathrm{cm}^{-1} above the 1E{}^1\mathrm{E} electronic state. Arguments associated with this level are used to provide experimental confirmation that the 1A1{}^1\mathrm{A}_1 is the upper singlet level and 1E{}^1\mathrm{E} is the lower singlet level.Comment: 19 pages, 6 figure

    Identification of Sonographic B-lines with Linear Transducer Predicts Elevated B-Type Natriuretic Peptide Level

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    Objective: This study sought to correlate the presence of pleural-based B-lines seen by emergency department ultrasound performed with the linear transducer with B-type natriuretic peptide (BNP) level in patients with suspected congestive heart failure.Methods: The study was a prospective convenience sample on adult patients in an academic, urban emergency department with over 100,000 annual patient visits. Adult patients with a BNP level ordered by the treating physician were prospectively enrolled by one of four physicians, blinded to the BNP level. The enrolling physicians included an emergency ultrasound director, two emergency ultrasound fellows, and a senior emergency medicine resident. Bedside ultrasound was performed using a 3-12 MHz linear broadband transducer in four lung fields. The serum BNP level was correlated with bilateral B-lines, defined as three or more comet-tail artifacts arising from the pleural line extending to the far field without a decrease in intensity on the right and left thorax.Results: Sixty three patients were consented and enrolled during a four-month period. Fifteen patients had the presence of bilateral B-lines. The median BNP in patients with bilateral B-lines was 1560 pg/mL (95% confidence interval (CI) 1141-3706 pg/mL), compared with 538 pg/mL (95% confidence interval 310-1917 pg/mL) in patients without B-lines. The distributions in the two groups differed significantly (p=0.0006). Based on the threshold level of BNP 500 pg/mL, the sensitivity of finding bilateral B-lines on ultrasound was 33.3% (95% CI: 0.19-0.50), and the specificity was 91.7% (95% CI: 0.73-0.99). In addition, bilateral B-lines were absent in all patients with a BNP<100 pg/mL.Conclusion: The presence of bilateral B-lines identified with the linear probe is associated with significantly higher BNP levels than patients without B-lines. In our patient population, the presence of B-lines was specific but not sensitive for BNP>500. Further research may show that it can be applied to quickly assess patients with undifferentiated dyspnea. [West J Emerg Med. 2011;12(1):102-106.

    Molecular Model of Prion Transmission to Humans

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    To assess interspecies barriers to transmission of transmissible spongiform encephalopathies, we investigated the ability of disease-associated prion proteins (PrPd) to initiate conversion of the human normal cellular form of prion protein of the 3 major PRNP polymorphic variants in vitro. Protein misfolding cyclic amplification showed that conformation of PrPd partly determines host susceptibility

    Molecular Model of Prion Transmission to Humans

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    Rona Barron - ORCID: 0000-0003-4512-9177 https://orcid.org/0000-0003-4512-9177To assess interspecies barriers to transmission of transmissible spongiform encephalopathies, we investigated the ability of disease-associated prion proteins (PrPd) to initiate conversion of the human normal cellular form of prion protein of the 3 major PRNP polymorphic variants in vitro. Protein misfolding cyclic amplification showed that conformation of PrPd partly determines host susceptibility.https://doi.org/10.3201%2Feid1512.09019415pubpub1

    Relation of statin use with non-melanoma skin cancer: prospective results from the Women\u27s Health Initiative.

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    BACKGROUND: The relationship between statin use and non-melanoma skin cancer (NMSC) is unclear with conflicting findings in literature. Data from the Women\u27s Health Initiative (WHI) Observational Study and WHI Clinical Trial were used to investigate the prospective relationship between statin use and NMSC in non-Hispanic white (NHW) postmenopausal women. METHODS: The WHI study enrolled women aged 50-79 years at 40 US centres. Among 133 541 NHW participants, 118 357 with no cancer history at baseline and complete medication/covariate data comprised the analytic cohort. The association of statin use (baseline, overall as a time-varying variable, duration, type, potency, lipophilicity) and NMSC incidence was determined using random-effects logistic regression models. RESULTS: Over a mean of 10.5 years of follow-up, we identified 11 555 NMSC cases. Compared with participants with no statin use, use of any statin at baseline was associated with significantly increased NMSC incidence (adjusted odds ratio (ORadj) 1.21; 95% confidence interval (CI): 1.07-1.35)). In particular, lovastatin (OR 1.52; 95% CI: 1.08-2.16), simvastatin (OR 1.38; 95% CI: 1.12-1.69), and lipophilic statins (OR 1.39; 95% CI: 1.18-1.64) were associated with higher NMSC risk. Low and high, but not medium, potency statins were associated with higher NMSC risk. No significant effect modification of the statin-NMSC relationship was found for age, BMI, smoking, solar irradiation, vitamin D use, and skin cancer history. CONCLUSIONS: Use of statins, particularly lipophilic statins, was associated with increased NMSC risk in postmenopausal white women in the WHI cohort. The lack of duration-effect relationship points to possible residual confounding. Additional prospective research should further investigate this relationship.British Journal of Cancer advance online publication, 7 January 2016; doi:10.1038/bjc.2015.376 www.bjcancer.com

    Change in Physical Activity and Sitting Time After Myocardial Infarction and Mortality Among Postmenopausal Women in the Women\u27s Health Initiative-Observational Study

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    BACKGROUND: How physical activity (PA) and sitting time may change after first myocardial infarction (MI) and the association with mortality in postmenopausal women is unknown. METHODS AND RESULTS: Participants included postmenopausal women in the Women\u27s Health Initiative-Observational Study, aged 50 to 79 years who experienced a clinical MI during the study. This analysis included 856 women who had adequate data on PA exposure and 533 women for sitting time exposures. Sitting time was self-reported at baseline, year 3, and year 6. Self-reported PA was reported at baseline through year 8. Change in PA and sitting time were calculated as the difference between the cumulative average immediately following MI and the cumulative average immediately preceding MI. The 4 categories of change were: maintained low, decreased, increased, and maintained high. The cut points were \u3e /=7.5 metabolic equivalent of task hours/week versus /=8 h/day versus /day for sitting time. Cox proportional hazard models estimated hazard ratios and 95% CIs for all-cause, coronary heart disease, and cardiovascular disease mortality. Compared with women who maintained low PA (referent), the risk of all-cause mortality was: 0.54 (0.34-0.86) for increased PA and 0.52 (0.36-0.73) for maintained high PA. Women who had pre-MI levels of sitting time /day, every 1 h/day increase in sitting time was associated with a 9% increased risk (hazard ratio=1.09, 95% CI: 1.01, 1.19) of all-cause mortality. CONCLUSIONS: Meeting the recommended PA guidelines pre- and post-MI may have a protective role against mortality in postmenopausal women

    An analysis of the effect of statins on the risk of Non-Hodgkin\u27s Lymphoma in the Women\u27s Health Initiative cohort.

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    Statins have been shown to induce a phosphoprotein signature that modifies MYC (myelocytomatosis viral oncogene) activation and to have anti-inflammatory activity that may impact the risk of Non-Hodgkin\u27s lymphoma (NHL). We analyzed the relationship between statins and risk of NHL using data from the Women\u27s Health Initiative (WHI). The study population included 161,563 postmenopausal women ages 50-79 years from which 712 cases of NHL were diagnosed after 10.8 years of follow-up. Information on statin use and other risk factors was collected by self- and interviewer-administered questionnaires. Multivariable-adjusted HR and 95% CI evaluating the relationship between statin use at baseline, as well as in a time-dependent manner and risk of NHL, were computed from Cox proportional hazards analyses. A separate analysis was performed for individual NHL subtypes: diffuse large B-Cell lymphoma (DLBCL) (n = 228), follicular lymphoma (n = 169), and small lymphocytic lymphoma (n = 74). All statistical tests were two-sided. There was no significant association between use of statins at baseline and risk of NHL (HR 0.85, 95% C.I. 0.67-1.08). However, in the multivariable-adjusted time-dependent models, statin use was associated with a borderline lower risk of NHL (HR 0.81, 95% C.I. 0.66-1.00). Considering subtypes of NHL, statin use was associated with a lower risk of DLBCL (HR 0.62, 95% C.I. 0.42-0.91). This effect was driven by lipophilic statins (HR 0.62, 95% C.I. 0.40-0.96). In the WHI, statins were associated with a lower overall risk of DLBCL, particularly attributable to lipophilic statins. These results may have impact on primary or secondary prevention of NHL, particularly DLBCL
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