2,149 research outputs found
Dipeptidyl-peptidase-4 inhibitors and pancreatic cancer: a cohort study
AimsâDipeptidyl-peptidase-4 inhibitors (DPP-4i) have been implicated with an increased pancreatic cancer risk. We therefore compared pancreatic cancer incidence and diagnostic work-up among initiators of DPP-4i versus sulfonylureas (SU) and thiazolidinediones (TZD). MethodsâMedicare claims data were examined in a new-user active-comparator cohort study. Patients >65 years with no prescriptions for DPP-4i, SU or TZD at baseline were included if they had at least two claims for the same drug within 180 days. Using an as-treated approach and propensity score-adjusted Cox models, we estimated hazard ratios (HR) and 95% confidence intervals (CI) for pancreatic cancer. Diagnostic work-up was compared using risk ratios (RR). RESULTSâIn the DPP-4i vs SU comparison, there were 18,179 DPP4i initiators of which 26 developed pancreatic cancer (follow-up time interquartile range 5â18 months). In the DPP-4i vs TZD comparison there were 29,366 DPP-4i initiators and 52 developed pancreatic cancer. The hazard of pancreatic cancer with DPP-4i was lower relative to SU (HR=0.6, CI 0.4â0.9) and similar to TZD (HR=1.0, CI 0.7â1.4). Excluding first 6 months of follow-up to reduce the potential for reverse causality did not alter results. Probability of diagnostic work-up post-initiation among DPP-4i initiators (79.3%) was similar to TZD (74.1%) (RR=1.06, CI 1.05â1.07) and SU (74.6%) (RR=1.06, CI1.05â1.07). The probability of diagnostic workup pre-index was ~80% for all cohorts. ConclusionâThough limited by sample size and the observed duration of treatment in the US, our well-controlled population based study suggests no increased short-term pancreatic cancer risk with DPP-4i relative to SU or TZD
Signals for strange quark contributions to the neutrino (antineutrino) scattering in quasi-elastic region
Strange quark contributions to the neutrino (antineutrino) scattering are
investigated on the elastic neutrino-nucleon scattering and the
neutrino-nucleus scattering for 12C target in the quasi-elastic region on the
incident energy of 500 MeV, within the framework of a relativistic single
particle model. For the neutrino-nucleus scattering, the effects of final state
interaction for the knocked-out nucleon are included by a relativistic optical
potential. In the cross sections we found some cancellations of the strange
quark contributions between the knocked-out protons and neutrons. Consequently,
the asymmetries between the incident neutrino and antineutrino which is the
ratio of neutral current to charged current, and the difference between the
asymmetries are shown to be able to yield more feasible quantities for the
strangeness effects. In order to explicitly display importance of the
cancellations, results of the exclusive reaction 16O(\nu, \nu' p) are
additionally presented for detecting the strangeness effects.Comment: 14 pages, 8 figures, submitted to Phys. Lett.
Measurement of the Dielectric Strength of Titanium Dioxide Ceramics
Titanium dioxide ceramics (TiO2) are candidate materials for high energy density pulsed power devices. Experiments to quantify the dielectric strength of TiO2 have been performed on a limited number of unoptimized samples. A high voltage test set was constructed to test the titanium dioxide. All samples had a relative dielectric constant of 100, all samples were of 3 mm nominal thickness, and all tests were performed in water dielectric to reduce the effect of the triple point field enhancement at the electrode edge. Both single layer and laminated samples were tested and the breakdown field strengths were recorded. Voltage risetimes varied slightly around 400 ns depending upon the size of the test sample area. Areas varied from \u3c 0.2 cm^2 to \u3e 100 cm^2. Both single layer and laminated material showed a strong area effect where the dielectric strength dropped off as area to the -0.17 and -0.1 power respectively. Effective areas of the electrodes were calculated using a field solver program. Breakdown field strengths varied from 469 kV/cm to 124 kV/cm in the single layer specimens, and from 556 kV/cm to 261 kV/cm in the laminates over an increasing area range. Energy density calculations for the material show that at areas of approximately 100 cm^2 the laminates can store nearly 3 times more energy than single layers
Cucumber mosaic virus and its 2b protein alter emission of host volatile organic compounds but not aphid vector settling in tobacco
Aphids, including the generalist herbivore Myzus persicae, transmit cucumber mosaic virus (CMV). CMV (strain Fny) infection affects M. persicae feeding behavior and performance on tobacco (Nicotiana tabacum), Arabidopsis thaliana and cucurbits in varying ways. In Arabidopsis and cucurbits, CMV decreases host quality and inhibits prolonged feeding by aphids, which may enhance virus transmission rates. CMV-infected cucurbits also emit deceptive, aphid-attracting volatiles, which may favor virus acquisition. In contrast, aphids on CMV-infected tobacco (cv. Xanthi) exhibit increased survival and reproduction. This may not increase transmission but might increase virus and vector persistence within plant communities. The CMV 2b counter-defense protein diminishes resistance to aphid infestation in CMV-infected tobacco plants. We hypothesised that in tobacco CMV and its 2b protein might also alter the emission of volatile organic compounds that would influence aphid behavior
Laboratory and tentative interstellar detection of trans-methyl formate using the publicly available Green Bank Telescope PRIMOS survey
The rotational spectrum of the higher-energy trans conformational isomer of
methyl formate has been assigned for the first time using several pulsed-jet
Fourier transform microwave spectrometers in the 6-60 GHz frequency range. This
species has also been sought toward the Sagittarius B2(N) molecular cloud using
the publicly available PRIMOS survey from the Green Bank Telescope. We detect
seven absorption features in the survey that coincide with laboratory
transitions of trans-methyl formate, from which we derive a column density of
3.1 (+2.6, -1.2) \times 10^13 cm-2 and a rotational temperature of 7.6 \pm 1.5
K. This excitation temperature is significantly lower than that of the more
stable cis conformer in the same source but is consistent with that of other
complex molecular species recently detected in Sgr B2(N). The difference in the
rotational temperatures of the two conformers suggests that they have different
spatial distributions in this source. As the abundance of trans-methyl formate
is far higher than would be expected if the cis and trans conformers are in
thermodynamic equilibrium, processes that could preferentially form
trans-methyl formate in this region are discussed. We also discuss measurements
that could be performed to make this detection more certain. This manuscript
demonstrates how publicly available broadband radio astronomical surveys of
chemically rich molecular clouds can be used in conjunction with laboratory
rotational spectroscopy to search for new molecules in the interstellar medium.Comment: 40 pages, 7 figures, 4 tables; accepted for publication in Ap
Measurement of nuclide cross-sections of spallation residues in 1 A GeV 238U + proton collisions
The production of heavy nuclides from the spallation-evaporation reaction of
238U induced by 1 GeV protons was studied in inverse kinematics. The
evaporation residues from tungsten to uranium were identified in-flight in mass
and atomic number. Their production cross-sections and their momentum
distributions were determined. The data are compared with empirical
systematics. A comparison with previous results from the spallation of 208Pb
and 197Au reveals the strong influence of fission in the spallation of 238U.Comment: 20 pages, 10 figures, background information at
http://www-wnt.gsi.de/kschmidt
The feasibility of using pedometers and brief advice to increase activity in sedentary older women:a pilot study
Background: People over the age of 70 carry the greatest burden of chronic disease, disability and health care use. Participation in physical activity is crucial for health, and walking accounts for much of the physical activity undertaken by sedentary individuals. Pedometers are a useful motivational tool to encourage increased walking and they are cheap and easy to use. The aim of this pilot study was to evaluate the feasibility of the use of pedometers plus a theory-based intervention to assist sedentary older women to accumulate increasing amounts of physical activity, mainly through walking. Methods: Female participants over the age of 70 were recruited from primary care and randomised to receive either pedometer plus a theory-based intervention or a theory-based intervention alone. The theory-based intervention consisted of motivational techniques, goal-setting, barrier identification and self-monitoring with pedometers and daily diaries. The pedometer group were further randomised to one of three target groups: a 10%, 15% or 20% monthly increase in step count to assess the achievability and acceptability of a range of targets. The primary outcome was change in daily activity levels measured by accelerometry. Secondary outcome measures were lower limb function, health related quality of life, anxiety and depression. Results: 54 participants were recruited into the study, with an average age of 76. There were 9 drop outs, 45 completing the study. All participants in the pedometer group found the pedometers easy to use and there was good compliance with diary keeping (96% in the pedometer group and 83% in the theory-based intervention alone group). There was a strong correlation (0.78) between accelerometry and pedometer step counts i.e. indicating that walking was the main physical activity amongst participants. There was a greater increase in activity (accelerometry) amongst those in the 20% target pedometer group compared to the other groups, although not reaching statistical significance (p = 0.192). Conclusion: We have demonstrated that it is feasible to use pedometers and provide theory-based advice to community dwelling sedentary older women to increase physical activity levels and a larger study is planned to investigate this further.Publisher PDFPeer reviewe
Anisotropic optical response of the diamond (111)-2x1 surface
The optical properties of the 21 reconstruction of the diamond (111)
surface are investigated. The electronic structure and optical properties of
the surface are studied using a microscopic tight-binding approach. We
calculate the dielectric response describing the surface region and investigate
the origin of the electronic transitions involving surface and bulk states. A
large anisotropy in the surface dielectric response appears as a consequence of
the asymmetric reconstruction on the surface plane, which gives rise to the
zigzag Pandey chains. The results are presented in terms of the reflectance
anisotropy and electron energy loss spectra. While our results are in good
agreement with available experimental data, additional experiments are proposed
in order to unambiguously determine the surface electronic structure of this
interesting surface.Comment: REVTEX manuscript with 6 postscript figures, all included in uu file.
Also available at http://www.phy.ohiou.edu/~ulloa/ulloa.html Submitted to
Phys. Rev.
Strange Quark Contributions to Parity-Violating Asymmetries in the Backward Angle G0 Electron Scattering Experiment
We have measured parity-violating asymmetries in elastic electron-proton and
quasi-elastic electron-deuteron scattering at Q^2 = 0.22 and 0.63 GeV^2. They
are sensitive to strange quark contributions to currents in the nucleon, and to
the nucleon axial current. The results indicate strange quark contributions of
< 10% of the charge and magnetic nucleon form factors at these four-momentum
transfers. We also present the first measurement of anapole moment effects in
the axial current at these four-momentum transfers.Comment: 5 pages, 2 figures, changed references, typo, and conten
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