Summary Background Evidence from Europe, Asia, and North America suggests that standard three-drug regimens of a proton-pump inhibitor plus amoxicillin and clarithromycin are significantly less ...effective for eradication of Helicobacter pylori infection than are 5-day concomitant and 10-day sequential four-drug regimens that include a nitroimidazole. These four-drug regimens also entail fewer antibiotic doses than do three-drug regimens and thus could be suitable for eradication programmes in low-resource settings. Few studies in Latin America have been done, where the burden of H pylori -associated diseases is high. We therefore did a randomised trial in Latin America comparing the effectiveness of four-drug regimens given concomitantly or sequentially with that of a standard 14-day regimen of triple therapy. Methods Between September, 2009, and June, 2010, we did a randomised trial of empiric 14-day triple, 5-day concomitant, and 10-day sequential therapies for H pylori in seven Latin American sites: Chile, Colombia, Costa Rica, Honduras, Nicaragua, and Mexico (two sites). Participants aged 21–65 years who tested positive for H pylori by a urea breath test were randomly assigned by a central computer using a dynamic balancing procedure to: 14 days of lansoprazole, amoxicillin, and clarithromycin (standard therapy); 5 days of lansoprazole, amoxicillin, clarithromycin, and metronidazole (concomitant therapy); or 5 days of lansoprazole and amoxicillin followed by 5 days of lansoprazole, clarithromycin, and metronidazole (sequential therapy). Eradication was assessed by urea breath test 6–8 weeks after randomisation. The trial was not masked. Our primary outcome was probablity of H pylori eradication. Our analysis was by intention to treat. This trial is registered with ClinicalTrials.gov , registration number NCT01061437. Findings 1463 participants aged 21–65 years were randomly allocated a treatment: 488 were treated with 14-day standard therapy, 489 with 5-day concomitant therapy, and 486 with 10-day sequential therapy. The probability of eradication with standard therapy was 82·2% (401 of 488), which was 8·6% higher (95% adjusted CI 2·6–14·5) than with concomitant therapy (73·6% 360 of 489) and 5·6% higher (–0·04% to 11·6) than with sequential therapy (76·5% 372 of 486). Neither four-drug regimen was significantly better than standard triple therapy in any of the seven sites. Interpretation Standard 14-day triple-drug therapy is preferable to 5-day concomitant or 10-day sequential four-drug regimens as empiric therapy for H pylori infection in diverse Latin American populations. Funding Bill & Melinda Gates Foundation, US National Institutes of Health.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
ABSTRACT X-ray observations of supernova remnants (SNRs) allow us to investigate the chemical inhomogeneity of ejecta, offering unique insight into the nucleosynthesis in supernova explosions. Here ...we present detailed imaging and spectroscopic studies of the "Fe knot" located along the eastern rim of the Type Ia SNR Tycho (SN 1572) using Suzaku and Chandra long-exposure data. Surprisingly, the Suzaku spectrum of this knot shows no emission from Cr, Mn, or Ni, which is unusual for the Fe-rich regions in this SNR. Within the framework of the canonical delayed-detonation models for SN Ia, the observed mass ratios , , and (at 90% confidence) can only be achieved for a peak temperature of (5.3-5.7) K and a neutron excess of . These constraints rule out the deep, dense core of a Chandrasekhar-mass white dwarf as the origin of the Fe knot and favor either incomplete Si burning or an -rich freeze-out regime, probably close to the boundary. An explosive He burning regime is a possible alternative, although this hypothesis is in conflict with the main properties of this SNR.
The physical process whereby a carbon-oxygen white dwarf explodes as a Type Ia supernova (SN Ia) remains highly uncertain. The degree of neutronization in SN Ia ejecta holds clues to this process ...because it depends on the mass and the metallicity of the stellar progenitor, and on the thermodynamic history prior to the explosion. We report on a new method to determine ejecta neutronization using Ca and S lines in the X-ray spectra of Type Ia supernova remnants (SNRs). Applying this method to Suzaku data of Tycho, Kepler, 3C 397, and G337.2−0.7 in the Milky Way, and N103B in the Large Magellanic Cloud, we find that the neutronization of the ejecta in N103B is comparable to that of Tycho and Kepler, which suggests that progenitor metallicity is not the only source of neutronization in SNe Ia. We then use a grid of SN Ia explosion models to infer the metallicities of the stellar progenitors of our SNRs. The implied metallicities of 3C 397, G337.2−0.7, and N103B are major outliers compared to the local stellar metallicity distribution functions, indicating that progenitor metallicity can be ruled out as the origin of neutronization for these SNRs. Although the relationship between ejecta neutronization and equivalent progenitor metallicity is subject to uncertainties stemming from the 12C + 16O reaction rate, which affects the Ca/S mass ratio, our main results are not sensitive to these details.
Type Ia supernovae originate from the explosion of carbon-oxygen white dwarfs in binary systems, but the exact nature of their progenitors remains elusive. The bulk properties of Type Ia supernova ...remnants, such as the radius and the centroid energy of the Fe K blend in the X-ray spectrum, are determined by the properties of the supernova ejecta and the ambient medium. We model the interaction between Chandrasekhar and sub-Chandrasekhar models for Type Ia supernova ejecta and a range of uniform ambient medium densities in one dimension up to an age of 5000 years. We generate synthetic X-ray spectra from these supernova remnant models and compare their bulk properties at different expansion ages with X-ray observations from Chandra and Suzaku. We find that our models can successfully reproduce the bulk properties of most observed remnants, suggesting that Type Ia SN progenitors do not modify their surroundings significantly on scales of a few pc, although more detailed models are required to establish quantitative limits on the density of any such surrounding circumstellar material. Ambient medium density and expansion age are the main contributors to the diversity of the bulk properties in our models. Chandrasekhar and sub-Chandrasekhar progenitors make similar predictions for the bulk remnant properties, but detailed fits to X-ray spectra have the power to discriminate explosion energetics and progenitor scenarios.
Planning and operation of Smart energetic have become more complex to analyse due to structural changes in the energy sector. The inclusion of distributed generation sources, generation with ...renewable sources, storage systems, and the dislocation of information between the different organization levels and actors lead to the inherent difficulty of defining appropriate models that help decision making. Nowadays, decisions in planning and operation are made level by level rather than integrated manner. To address this problem, this work proposes a multi-level methodological framework based on Key Performance Indicators and System of Systems concepts. Involving methods, both quantitative and qualitative, this work serves as guidance to managers, planners, or political decision-makers from any electrical enterprise to help them find suitable solutions for planning and operation of smart grid projects.
IMPORTANCE The long-term effectiveness of Helicobacter pylori eradication programs for preventing gastric cancer will depend on recurrence risk and individual and community factors. OBJECTIVE To ...estimate risk of H pylori recurrence and assess factors associated with successful eradication 1 year after treatment. DESIGN, SETTING, AND PARTICIPANTS Cohort analysis of 1463 randomized trial participants aged 21 to 65 years from 7 Latin American communities, who were treated for H pylori and observed between September 2009 and July 2011. INTERVENTIONS Randomization to 1 of 3 treatment groups: 14-day lansoprazole, amoxicillin, and clarithromycin (triple therapy); 5-day lansoprazole and amoxicillin followed by 5-day lansoprazole, clarithromycin, and metronidazole (sequential); or 5-day lansoprazole, amoxicillin, clarithromycin, and metronidazole (concomitant). Participants with a positive (13) C-urea breath test (UBT) 6 to 8 weeks posttreatment were offered voluntary re-treatment with 14-day bismuth-based quadruple therapy. MEASUREMENTS Recurrent infection after a negative posttreatment UBT and factors associated with successful eradication at 1-year follow-up. RESULTS Among participants with UBT-negative results who had a 1-year follow-up UBT (n=1091), 125 tested UBT positive, a recurrence risk of 11.5% (95% CI, 9.6%-13.5%). Recurrence was significantly associated with study site (P = .03), nonadherence to initial therapy (adjusted odds ratio AOR, 2.94; 95% CI, 1.31-6.13; P = .01), and children in the household (AOR, 1.17; 95% CI, 1.01-1.35 per child; P = .03). Of the 281 with positive posttreatment UBT results, 138 completed re-treatment, of whom 93 tested UBT negative at 1 year. Among the 1340 who had a 1-year UBT, 80.4% (95% CI, 76.4%-83.9%), 79.8% (95% CI, 75.8%-83.5%), and 77.8% (95% CI, 73.6%-81.6%) had UBT-negative results in the triple, sequential, and concomitant groups, respectively (P = .61), with 79.3% overall effectiveness (95% CI, 77.1%-81.5%). In a single-treatment course analysis that ignored the effects of re-treatment, the percentage of UBT-negative results at 1 year was 72.4% (95% CI, 69.9%-74.8%) and was significantly associated with study site (P < .001), adherence to initial therapy (AOR, 0.26; 95% CI, 0.15-0.42; P < .001), male sex (AOR, 1.63; 95% CI, 1.25-2.13; P < .001), and age (AOR, 1.14; 95% CI, 1.02-1.27 per decade; P = .02). One-year effectiveness among all 1463 enrolled participants, considering all missing UBT results as positive, was 72.7% (95% CI, 70.3%-74.9%). CONCLUSIONS AND RELEVANCE One year after treatment for H pylori infection, recurrence occurred in 11.5% of participants who had negative posttreatment UBT results. Recurrence determinants (ie, nonadherence and demographics) may be as important as specific antibiotic regimen in determining the long-term success of H pylori eradication interventions. Study findings are relevant to the feasibility of programs for the primary prevention of gastric cancer in high-incidence regions of Latin America. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT01061437
SNe Ia Keep Memory of Their Progenitor Metallicity Piersanti, Luciano; Bravo, Eduardo; Cristallo, Sergio ...
Astrophysical journal. Letters,
02/2017, Volume:
836, Issue:
1
Journal Article, Publication
Peer reviewed
Open access
The ultimate understanding of SNe Ia diversity is one of the most urgent issues to exploit thermonuclear explosions of accreted White Dwarfs (WDs) as cosmological yardsticks. In particular, we ...investigate the impact of the progenitor system metallicity on the physical and chemical properties of the WD at the explosion epoch. We analyze the evolution of CO WDs through the accretion and simmering phases by using evolutionary models based on time-dependent convective mixing and an extended nuclear network including the most important electron captures, beta decays, and URCA processes. We find that, due to URCA processes and electron-captures, the neutron excess and density at which the thermal runaway occurs are substantially larger than previously claimed. Moreover, we find that the higher the progenitor metallicity, the larger the neutron excess variation during the accretion and simmering phases and the higher the central density and the convective velocity at the explosion. Hence, the simmering phase acts as an amplifier of the differences existing in SNe Ia progenitors. When applying our results to the neutron excess estimated for the Tycho and Kepler young supernova remnants, we derive that the metallicity of the progenitors should be in the range , close to the average metallicity value of the thin disk of the Milky Way. As the amount of produced in the explosion depends on the neutron excess and central density at the thermal runaway, our results suggest that the light curve properties depend on the progenitor metallicity.
The use of Mg as an alloying element in copper alloys has largely been overlooked in scientific literature and technological applications. Its supposed tribological compatibility with iron makes it ...an interesting option to replace Pb in tribological alloys. This work describes the casting process of high-quality thin slabs of Cu-Mg-Sn alloys with different compositions by means of conventional methods. The resulting phases were analyzed using X-ray diffraction, scanning electron microscopy, optical microscopy, and energy dispersive X-ray spectroscopy techniques. Typical dendritic
α
-Cu, eutectic Cu
2
Mg(Sn) and eutectoid non-equilibrium microstructures were found. Tensile tests and Vickers microhardness show the excellent hardening capability of Mg as compared to other copper alloys in the as-cast condition. For some of the slabs and compositions, cold rolling reductions of over 95 pct have been easily achieved. Other compositions and slabs have failed during the deformation process. Failure analysis after cold rolling reveals that one cause for brittleness is the presence of casting defects such as microshrinkage and inclusions, which can be eliminated. However, for high Mg contents, a high volume fraction of the intermetallic phase provides a contiguous path for crack propagation through the connected interdendritic regions.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
9.
SNR-calibrated Type Ia supernova models Bravo, Eduardo; Badenes, Carles; Martínez-Rodríguez, Héctor
Monthly notices of the Royal Astronomical Society,
02/2019, Volume:
482, Issue:
4
Journal Article
Gastric adenocarcinoma (GA) has changed in recent decades. Cancer estimates are often calculated from population-based cancer registries, which lack valuable information to guide decision-making ...(clinical outcomes). We describe the trends in clinical practice for GA using a hospital-based cancer registry over a timespan of 15 years.
A retrospective cohort study was conducted. Data were gathered from adults diagnosed and treated for GA at Fundación Valle del Lili (FVL), between 2000 and 2014, from the hospital's own cancer registry and crossed with Cali's Cancer Registry. Additional data were obtained directly from clinical records, pathology reports and the clinical laboratory. Patients younger than 18 years and those for whom limited information was available in the medical history were excluded. A survival analysis was conducted using Kaplan-Meier method.
A total of 500 patients met eligibility criteria. Median age was 64 years (IQR: 54-74 years), 39.8% were female, 22.2% were at an early stage, 32.2% had a locally advanced disease, and 29% a metastatic disease, 69% had intestinal subtype, 48.6% had a positive
test, 85.2% had a distal lesion, 62% underwent gastrectomy, 60.6% lymphadenectomy, and 40.6% received chemotherapy. Survival at 5 years for all cases was 39.9% (CI 95% 35.3-44.5). Survival decreased over time in all groups and was lower in age-groups <39 and 60-79 with either locally advanced or metastatic disease. Prognostic factors that were significant in the Cox proportional-hazards model were late stages of the tumor (locally advanced: HR=2.52; metastatic: HR=4.17), diffuse subtype (HR=1.40), gastrectomy (subtotal: HR=0.42; total: 0.44) and palliative chemotherapy (HR=0.61).
The treatment of GA has changed in recent decades. GA survival was associated with clinical staging, diffuse subtype, gastrectomy and palliative chemotherapy. These findings must be interpreted in the context of a hospital-based study.
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