Zastosowanie leku XENical w zapobieganiu cukrzycy u osób z otyłością — badanie XENDOS. Badanie randomizowane z zastosowaniem orlistatu jako dodatkowego, oprócz zmian stylu życia, czynnika zapobiegania cukrzycy typu 2 u pacjentów z otyłością

INTRODUCTION. It is well established that the risk of developing type 2 diabetes is closely linked to the presence and duration of overweight and obesity. A reduction in the incidence of type 2 diabetes with lifestyle changes has previously been demonstrated. We hypothesized that adding a weight-reducing agent to lifestyle changes may lead to an even greater decrease in body weight, and thus the incidence of type 2 diabetes, in obese patients. MATERIAL AND METHODS. In a 4-year, double-blind, prospective study, we randomized 3,305 patients to lifestyle changes plus either orlistat 120 mg or placebo, three times daily. Participants had a BMI &#8805; 30 kg/m2 and normal (79%) or impaired (21%) glucose tolerance (IGT). Primary endpoints were time to onset of type 2 diabetes and change in body weight. Analyses were by intention to treat. RESULTS. Of orlistat-treated patients, 52% completed treatment compared with 34% of placebo recipients (P < 0.0001). After 4 years&#8217; treatment, the cumulative incidence of diabetes was 9.0% with placebo and 6.2% with orlistat, corresponding to a risk reduction of 37.3% (P = 0.0032). Exploratory analyses indicated that the preventive effect was explained by the difference in subjects with IGT. Mean weight loss after 4 years was significantly greater with orlistat (5.8 vs. 3.0 kg with placebo; P < 0.001) and similar between orlistat recipients with impaired (5.7 kg) or normal glucose tolerance (NGT) (5.8 kg) at baseline. A second analysis in which the baseline weights of subjects who dropped out of the study was carried forward also demonstrated greater weight loss in the orlistat group (3.6 vs. 1.4 kg; P < 0.001). CONCLUSIONS. Compared with lifestyle changes alone, orlistat plus lifestyle changes resulted in a greater reduction in the incidence of type 2 diabetes over 4 years and produced greater weight loss in a clinically representative obese population. Difference in diabetes incidence was detectable only in the IGT subgroup; weight loss was similar in subjects with IGT and or NGT.WSTĘP. Ryzyko rozwoju cukrzycy typu 2 wiąże się ściśle z obecnością i czasem trwania nadwagi oraz otyłości. Wpływ wprowadzenia zmian stylu życia na zmniejszenie częstości cukrzycy typu 2 potwierdzono we wcześniejszych badaniach. Wysunięto hipotezę, według której zastosowanie dodatkowego czynnika powodującego zmniejszenie masy ciała u chorych, którym udało się ten cel częściowo osiągnąć pod wpływem zmiany stylu życia, pozwala uzyskać jeszcze lepsze efekty, a w konsekwencji prowadzi do dalszej redukcji częstości cukrzycy typu 2 u pacjentów z otyłością. MATERIAŁ I METODY. Do trwającego 4 lata, prospektywnego, randomizowanego badania, przeprowadzonego metodą podwójnie ślepej próby zakwalifikowano 3305 pacjentów, których losowo podzielono na dwie grupy. W pierwszej grupie, obok wprowadzenia zmian stylu życia, pacjentom podawano 3 razy na dobę orlistat w dawce 120 mg, a w drugiej &#8212; placebo. Wskaźnik masy ciała (BMI, body mass index) uczestników badania był większy lub równy 30 kg/m2, stężenie glukozy było prawidłowe (79%) lub rozpoznawano upośledzoną tolerancję glukozy (IGT, impaired glucose tolerance) (21%). Jako główne kryterium oceny badania przyjęto czas do wystąpienia cukrzycy typu 2 oraz zmianę masy ciała. Przeprowadzono analizę według pierwotnej intencji leczenia (intention to treat). WYNIKI. Leczenie ukończyło 52% badanych otrzymujących orlistat i 34% przyjmujących placebo (p < 0,0001). Po 4 latach terapii skumulowane ryzyko wystąpienia cukrzycy w grupie otrzymującej placebo wyniosło 9%, natomiast w grupie przyjmującej orlistat &#8212; 6,2%, co oznacza redukcję ryzyka o 37,3% (p = 0,0032). Na podstawie analizy uzyskanych danych stwierdzono, że efekt prewencyjny wynikał z różnic wśród pacjentów z upośledzoną tolerancją glukozy. Średnia redukcja masy ciała po 4 latach obserwacji była znacząco wyższa w grupie leczonej orlistatem (5,8 vs. 3,0 kg w grupie otrzymującej placebo; p < 0,001) oraz podobna u pacjentów otrzymujących orlistat z wyjściową upośledzoną (5,7 kg) lub prawidłową tolerancją glukozy (NGT, normal glucose tolerance) (5,8 kg). W drugiej analizie, w której uwzględniono zmiany masy ciała u osób wyłączonych z badania, również wykazano większą redukcję masy ciała w grupie leczonej orlistatem (3,6 vs. 1,4 kg; p < 0,001). WNIOSKI. W badaniu przeprowadzonym w reprezentatywnej populacji osób z otyłością wykazano, że w porównaniu z postępowaniem opartym wyłącznie na zmianie stylu życia, dodanie orlistatu spowodowało większy spadek częstości cukrzycy typu 2 oraz większą redukcję masy ciała w okresie 4 lat. Różnica w częstości cukrzycy była widoczna tylko w podgrupie z IGT, zmniejszenie masy ciała było podobne zarówno w podgrupie z IGT, jak i z NGT

Dual-readout Calorimetry

The RD52 Project at CERN is a pure instrumentation experiment whose goal is to understand the fundamental limitations to hadronic energy resolution, and other aspects of energy measurement, in high energy calorimeters. We have found that dual-readout calorimetry provides heretofore unprecedented information event-by-event for energy resolution, linearity of response, ease and robustness of calibration, fidelity of data, and particle identification, including energy lost to binding energy in nuclear break-up. We believe that hadronic energy resolutions of {\sigma}/E $\approx$ 1 - 2% are within reach for dual-readout calorimeters, enabling for the first time comparable measurement preci- sions on electrons, photons, muons, and quarks (jets). We briefly describe our current progress and near-term future plans. Complete information on all aspects of our work is available at the RD52 website http://highenergy.phys.ttu.edu/dream/.Comment: 10 pages, 10 figures, Snowmass White pape

Measurement of the Xi-p Scattering Cross Sections at Low Energy

In this paper we report cross-section measurements for $\Xi^-p$ elastic and inelastic scatterings at low energy using a scintillating fiber active target. Upper limit on the total cross-section for the elastic scattering was found to be 24 mb at 90% confidence level, and the total cross section for the $\Xi^-p\to\Lambda\Lambda$ reaction was found to be $4.3^{+6.3}_{-2.7}$ mb. We compare the results with currently competing theoretical estimates.Comment: 9 page

Evaluation of turbulent dissipation rate retrievals from Doppler Cloud Radar

Turbulent dissipation rate retrievals from cloud radar Doppler velocity measurements are evaluated using independent, in situ observations in Arctic stratocumulus clouds. In situ validation data sets of dissipation rate are derived using sonic anemometer measurements from a tethered balloon and high frequency pressure variation observations from a research aircraft, both flown in proximity to stationary, ground-based radars. Modest biases are found among the data sets in particularly low- or high-turbulence regimes, but in general the radar-retrieved values correspond well with the in situ measurements. Root mean square differences are typically a factor of 4-6 relative to any given magnitude of dissipation rate. These differences are no larger than those found when comparing dissipation rates computed from tetheredballoon and meteorological tower-mounted sonic anemometer measurements made at spatial distances of a few hundred meters. Temporal lag analyses suggest that approximately half of the observed differences are due to spatial sampling considerations, such that the anticipated radar-based retrieval uncertainty is on the order of a factor of 2-3. Moreover, radar retrievals are clearly able to capture the vertical dissipation rate structure observed by the in situ sensors, while offering substantially more information on the time variability of turbulence profiles. Together these evaluations indicate that radar-based retrievals can, at a minimum, be used to determine the vertical structure of turbulence in Arctic stratocumulus clouds

Radiogenic backgrounds in the NEXT double beta decay experiment

Natural radioactivity represents one of the main backgrounds in the search for neutrinoless double beta decay. Within the NEXT physics program, the radioactivity- induced backgrounds are measured with the NEXT-White detector. Data from 37.9 days of low-background operations at the Laboratorio Subterráneo de Canfranc with xenon depleted in 136Xe are analyzed to derive a total background rate of (0.84±0.02) mHz above 1000 keV. The comparison of data samples with and without the use of the radon abatement system demonstrates that the contribution of airborne-Rn is negligible. A radiogenic background model is built upon the extensive radiopurity screening campaign conducted by the NEXT collaboration. A spectral fit to this model yields the specific contributions of 60Co, 40K, 214Bi and 208Tl to the total background rate, as well as their location in the detector volumes. The results are used to evaluate the impact of the radiogenic backgrounds in the double beta decay analyses, after the application of topological cuts that reduce the total rate to (0.25±0.01) mHz. Based on the best-fit background model, the NEXT-White median sensitivity to the two-neutrino double beta decay is found to be 3.5σ after 1 year of data taking. The background measurement in a Qββ±100 keV energy window validates the best-fit background model also for the neutrinoless double beta decay search with NEXT-100. Only one event is found, while the model expectation is (0.75±0.12) events. [Figure not available: see fulltext.]

Demonstration of the event identification capabilities of the NEXT-White detector

In experiments searching for neutrinoless double-beta decay, the possibility of identifying the two emitted electrons is a powerful tool in rejecting background events and therefore improving the overall sensitivity of the experiment. In this paper we present the first measurement of the efficiency of a cut based on the different event signatures of double and single electron tracks, using the data of the NEXT-White detector, the first detector of the NEXT experiment operating underground. Using a 228Th calibration source to produce signal-like and background-like events with energies near 1.6 MeV, a signal efficiency of 71.6 ± 1.5 stat± 0.3 sys% for a background acceptance of 20.6 ± 0.4 stat± 0.3 sys% is found, in good agreement with Monte Carlo simulations. An extrapolation to the energy region of the neutrinoless double beta decay by means of Monte Carlo simulations is also carried out, and the results obtained show an improvement in background rejection over those obtained at lower energies. [Figure not available: see fulltext.

Soft-core hyperon-nucleon potentials

A new Nijmegen soft-core OBE potential model is presented for the low-energy YN interactions. Besides the results for the fit to the scattering data, which largely defines the model, we also present some applications to hypernuclear systems using the G-matrix method. An important innovation with respect to the original soft-core potential is the assignment of the cut-off masses for the baryon-baryon-meson (BBM) vertices in accordance with broken SU(3)$_F$, which serves to connect the NN and the YN channels. As a novel feature, we allow for medium strong breaking of the coupling constants, using the $^3P_0$ model with a Gell-Mann--Okubo hypercharge breaking for the BBM coupling. We present six hyperon-nucleon potentials which describe the available YN cross section data equally well, but which exhibit some differences on a more detailed level. The differences are constructed such that the models encompass a range of scattering lengths in the $\Sigma N$ and $\Lambda N$ channels. For the scalar-meson mixing angle we obtained values $\theta_S=37$ to 40 degrees, which points to almost ideal mixing angles for the scalar $q\bar{q}$ states. The G-matrix results indicate that the remarkably different spin-spin terms of the six potentials appear specifically in the energy spectra of $\Lambda$ hypernuclei.Comment: 37 pages, 4 figure

Low-diffusion Xe-He gas mixtures for rare-event detection: electroluminescence yield

High pressure xenon Time Projection Chambers (TPC) based on secondary scintillation (electroluminescence) signal amplification are being proposed for rare event detection such as directional dark matter, double electron capture and double beta decay detection. The discrimination of the rare event through the topological signature of primary ionisation trails is a major asset for this type of TPC when compared to single liquid or double-phase TPCs, limited mainly by the high electron diffusion in pure xenon. Helium admixtures with xenon can be an attractive solution to reduce the electron diffu- sion significantly, improving the discrimination efficiency of these optical TPCs. We have measured the electroluminescence (EL) yield of Xe–He mixtures, in the range of 0 to 30% He and demonstrated the small impact on the EL yield of the addition of helium to pure xenon. For a typical reduced electric field of 2.5 kV/cm/bar in the EL region, the EL yield is lowered by ∼ 2%, 3%, 6% and 10% for 10%, 15%, 20% and 30% of helium concentration, respectively. This decrease is less than what has been obtained from the most recent simulation framework in the literature. The impact of the addition of helium on EL statistical fluctuations is negligible, within the experimental uncertainties. The present results are an important benchmark for the simulation tools to be applied to future optical TPCs based on Xe-He mixtures. [Figure not available: see fulltext.]