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Filtered neutron technique was applied for producing quasi-monoenergetic neutron beams of 24 keV, 54 keV, 133 keV and 148 keV at the horizontal neutron channel No. 4 of the Dalat Nuclear Research Reactor. The study on physical characteristics of these beam lines has been carried out for efficient applications in neutron capture experiments. The filtered neutron spectrum of each beam has been simulated by Monte-Carlo method and experimentally measured by a gas-filled protonrecoil spectrometer. The neutron fluxes of these filtered beams were measured by the activation technique with standard foils of 197Au, using a high efficient HPGe digital gamma-ray spectrometer.
Interaction between proton pump inhibitors (PPI) and warfarin is controversial.
Previous clinical studies have only a short follow-up period. Methods and
Results: All patients (n = 716) for whom warfarin was prescribed from November
1, 2010 to October 30, 2011 were extracted from electronic health records. In
retrospective analysis for 1 year, PPI were prescribed to 404 patients. Among
them, 108 patients were taking warfarin for more than 6 weeks before and after
PPI. The profile of these patients was analyzed: 63 patients took lansoprazole;
15 patients took omeprazole; 30 patients took rabeprazole. No statistical
difference was observed among 3 groups in age, body weight, concomitant use of
other drugs, and comorbidity. Warfarin dose and INR did not change after PPI.
Multivariate stepwise logistic regression analysis revealed that upper quartile of increment of INR was associated with the
presence of atrial fibrillation (OR 3.77, 95% CI 1.16 - 12.27). The patients who had warfarin for shorter
periods before PPI, or those who had PPI first (n = 141) had similar dose of
warfarin and INR. In all patients analyzed (n = 404), including patients whose
follow-up periods were shorter than 6 weeks (n = 155), a patient had cerebral
bleeding, and 2 patients had cerebral infarction. Conclusions: Unfavorable
interaction between warfarin and PPI was negligible in clinical use. Relatively
higher INR was achieved after PPI in the presence of atrial fibrillation.
This paper presents the longitudinal
distribution of total ozone along several latitudinal circles from both hemispheres
during a strong geomagnetic storm that occurred on 24 August 2005 after a solar
proton event (the maximum flux of protons with energy > 10 MeV was 1.70 × 107 protons cm-2.day-1.sr-1 on 23 August). For
that, we use average daily values of total ozone observations (=column ozone
amount) in Dobson units for the period 18-25 August 2005 (obtained from the Total Ozone Mapping Spectrometer, TOMS).
The considered storm occurred after a relatively quiet geomagnetic period and
it is not superposed by another perturbation, which permit us to identify
clearly the effects of the geomagnetic storm on total ozone. The results show statistically significant decreases in ozone along the latitudinal
circles 70°N and 70°S (summer and winter), no
statistically significant effects at middle latitudes (40°S) and sparse statistically
significant increases at low latitudes (20°S). The role of some mechanisms to
explain the features observed is considered.
previously obtained analytical formulae for the dipole moments and angular
momenta of rotating spherical bodies. The resulting formulae were applied to
the Sun, the star 78 Virginis and the Earth. The agreement of the theoretical
formulae with the actual real situations is indeed remarkable. In this note we
apply the same formulae to the electron and the proton, using the classical
values of the radii, so no quantum mechanical treatment is considered.
To achieve a good therapeutic ratio the radiation dose to the tumor
should be as high as possible with the lowest possible dose to the surrounding
normal tissue. This is especially the case for brain tumors. Technological advancements
in diagnostic imaging, dose calculations, and radiation delivery systems,
combined with a better understanding of the pathophysiology of brain tumors have led to improvements in the therapeutic results. The widely used
technology of delivering 3-D conformal therapy with photon beams (gamma rays)
produced by Linear Accelerators has progressed into the use of Intensity
modulated radiation therapy (IMRT). Particle beams have been used for several
decades for radiotherapy because of their favorable depth dose characteristics.
The introduction of clinically dedicated proton beam therapy facilities has
improved the access for cancer patients to this treatment. Proton therapy is of
particular interest for pediatric malignancies. These technical improvements
are further enhanced by the evolution in tumor physiology imaging which allows
for improved delineation of the tumor. This in turn opens the potential to
adjust the radiation dose to maximize the radiobiological effects. The advances
in both imaging and radiation therapy delivery will be discussed.