10,683 research outputs found

    Reduced dimer production in solar-simulator-pumped continuous wave iodine lasers based on model simulations and scaling and pumping studies

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    A numerical rate equation model for a continuous wave iodine laser with longitudinally flowing gaseous lasant is validated by approximating two experiments that compare the perfluoroalkyl iodine lasants n-C3F7I and t-C4F9I. The salient feature of the simulations is that the production rate of the dimer (C4F9)2 is reduced by one order of magnitude relative to the dimer (C3F7)2. The model is then used to investigate the kinetic effects of this reduced dimer production, especially how it improves output power. Related parametric and scaling studies are also presented. When dimer production is reduced, more monomer radicals (t-C4F9) are available to combine with iodine ions, thus enhancing depletion of the laser lower level and reducing buildup of the principal quencher, molecular iodine. Fewer iodine molecules result in fewer downward transitions from quenching and more transitions from stimulated emission of lasing photons. Enhanced depletion of the lower level reduces the absorption of lasing photons. The combined result is more lasing photons and proportionally increased output power

    Locomotor hyperactivity in 14-3-3Zeta KO mice is associated with dopamine transporter dysfunction

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    Dopamine (DA) neurotransmission requires a complex series of enzymatic reactions that are tightly linked to catecholamine exocytosis and receptor interactions on pre- and postsynaptic neurons. Regulation of dopaminergic signalling is primarily achieved through reuptake of extracellular DA by the DA transporter (DAT) on presynaptic neurons. Aberrant regulation of DA signalling, and in particular hyperactivation, has been proposed as a key insult in the presentation of schizophrenia and related neuropsychiatric disorders. We recently identified 14-3-3ζ as an essential component of neurodevelopment and a central risk factor in the schizophrenia protein interaction network. Our analysis of 14-3-3ζ-deficient mice now shows that baseline hyperactivity of knockout (KO) mice is rescued by the antipsychotic drug clozapine. 14-3-3ζ KO mice displayed enhanced locomotor hyperactivity induced by the DA releaser amphetamine. Consistent with 14-3-3ζ having a role in DA signalling, we found increased levels of DA in the striatum of 14-3-3ζ KO mice. Although 14-3-3ζ is proposed to modulate activity of the rate-limiting DA biosynthesis enzyme, tyrosine hydroxylase (TH), we were unable to identify any differences in total TH levels, TH localization or TH activation in 14-3-3ζ KO mice. Rather, our analysis identified significantly reduced levels of DAT in the absence of notable differences in RNA or protein levels of DA receptors D1–D5. Providing insight into the mechanisms by which 14-3-3ζ controls DAT stability, we found a physical association between 14-3-3ζ and DAT by co-immunoprecipitation. Taken together, our results identify a novel role for 14-3-3ζ in DA neurotransmission and provide support to the hyperdopaminergic basis of pathologies associated with schizophrenia and related disorders.H Ramshaw, X Xu, EJ Jaehne, P McCarthy, Z Greenberg, E Saleh, B McClure, J Woodcock, S Kabbara, S Wiszniak, Ting-Yi Wang, C Parish, M van den Buuse, BT Baune, A Lopez and Q Schwar

    Attenuating Effect of Vigorous Physical Activity on the Risk for Inherited Obesity: A Study of 47,691 Runners

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    Objective: Physical activity has been shown to attenuate the effect of the FTO polymorphism on body weight, and the heritability of body weight in twin and in family studies. The dose-response relationship between activity and the risk for inherited obesity is not well known, particularly for higher doses of vigorous exercise. Such information is needed to best prescribe an exercise dose for obesity prevention in those at risk due to their family history. Design: We therefore analyzed self-reported usual running distance, body mass index (BMI), waist circumference, and mother’s and father’s adiposity (1 = lean, 2 = normal, 3 = overweight, and 4 = very overweight) from survey data collected on 33,480 male and 14,211 female runners. Age-, education-, and alcohol-adjusted regression analyses were used to estimate the contribution of parental adiposities to the BMI and waist circumferences in runners who ran an average of,3, 3–6, 6–9, 9km/day.Results:BMIandwaistcircumferencesofrunnerswhoran,3km/dayweresignificantlyrelatedtotheirparentsadiposity(P,10215andP,10211,respectively).Theserelationships(i.e.,kg/m2orcmperincrementinparentaladiposity)diminishedsignificantlywithincreasingrunningdistanceforbothBMI(inheritance6exerciseinteraction,males:P,10210;females:P,1025)andwaistcircumference(inheritance6exerciseinteraction,males:P,1029;females:P=0.004).Comparedto,3km/day,theparentalcontributiontorunnerswhoaveraged9 km/day. Results: BMI and waist circumferences of runners who ran,3 km/day were significantly related to their parents adiposity (P,10 215 and P,10 211, respectively). These relationships (i.e., kg/m 2 or cm per increment in parental adiposity) diminished significantly with increasing running distance for both BMI (inheritance6exercise interaction, males: P,10 210; females: P,10 25) and waist circumference (inheritance6exercise interaction, males: P,10 29; females: P = 0.004). Compared to,3 km/day, the parental contribution to runners who averaged 9 km/day was diminished by 48 % for male BMI, 58 % for female BMI, 55 % for male waist circumference, and 58 % for female waist circumference. These results could not b

    Patient characteristics associated with differences in patients' evaluation of their general practitioner

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    <p>Abstract</p> <p>Background</p> <p>Knowledge of the extent to which patient characteristics are systematically associated with variation in patient evaluations will enable us to adjust for differences between practice populations and thereby compare GPs. Whether this is appropriate depends on the purpose for which the patient evaluation was conducted. Associations between evaluations and patient characteristics may reflect gaps in the quality of care or may be due to inherent characteristics of the patients. This study aimed to determine such associations in a setting with a comprehensive list system and gate-keeping.</p> <p>Methods</p> <p>A nationwide Danish patient evaluation survey among voluntarily participating GPs using the EUROPEP questionnaire, which produced 28,260 patient evaluations (response rate 77.3%) of 365 GPs. In our analyses we compared the prevalence of positive evaluations in groups of patients.</p> <p>Results</p> <p>We found a positive GP assessment to be strongly associated with increasing patient age and increasing frequency of attendance. Patients reporting a chronic condition were more positive, whereas a low self-rated health was strongly associated with less positive scores also after adjustment. The association between patient gender and assessment was weak and inconsistent and depended on the focus. We found no association either with the patients' educational level or with the duration of listing with the GP even after adjusting for patient characteristics.</p> <p>Conclusion</p> <p>Adjustment for patient differences may produce a more fair comparison between GPs, but may also blur the assessment of GPs' ability to meet the needs of the populations actually served. On the other hand, adjusted results will enable us to describe the significance of specific patient characteristics to patients' experience of care.</p
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