185 research outputs found
Structural and optical studies of FeSb2 under high pressure
Nanostructured orthorhombic FeSb2 and an amorphous phase were formed by
mechanical alloying starting from a mixture of high purity elemental Fe and Sb
powders. The effects of high pressures on structural and optical properties
were studied using X-ray diffraction (XRD) and Raman spectroscopy (RS). XRD
patterns showed the presence of the orthorhombic FeSb2 phase up to the maximum
pressure applied (28.2 GPa). The XRD patterns showed also an increase in the
amount of the amorphous phase with increasing pressure up to 23.3 GPa. At 14.3
GPa, together with the former phases, a new phase was observed and indexed to a
tetragonal FeSb2 phase, but its volume fraction is small at least up to 23.3
GPa. For the orthorhombic FeSb2 phase, the pressure dependence of the volume
fitted to a Birch-Murnaghan equation of state gave a bulk modulus = 74.2 +- 3.0
GPa and its pressure derivative = 7.5 +- 0.6. RS measurements were performed
from atmospheric pressure up to 45.2 GPa. For the orthorhombic FeSb2 phase, the
Raman active mode was observed up to the maximum pressure applied, while the
mode disappeared at 16.6 GPa. For pressures higher than 21 GPa, the Raman
active mode of a tetragonal FeSb2 phase was observed, confirming ab initio
calculations reported in the literature.Comment: 31 pages, 11 figures and 2 tables. Already submitted for publicatio
Aging of a nanostructured Zn50Se50 alloy produced by mechanical alloying
The aging of a nanocrystalline equiatomic ZnSe alloy produced by mechanical
alloying was investigated using X-ray diffraction (XRD) and differential
scanning calorimetry (DSC) techniques. The measured XRD patterns showed that Se
atoms located at interfacial component migrated with aging giving raise to a
crystalline selenium (c-Se) phase. DSC spectra of heat-treated samples at
temperatures above 221oC followed by quenching showed that the c-Se particles
changed to the amorphous state. It was also observed that the as-milled and
aged samples are highly hydrophilic. The lattice parameters and the average
crystallite sizes were calculated as a function of time of aging and
temperature of heat treatment.Comment: Submitted to Solid State Communications, 4 figure
Modified iterative versus Laplacian Landau gauge in compact U(1) theory
Compact U(1) theory in 4 dimensions is used to compare the modified iterative
and the Laplacian fixing to lattice Landau gauge in a controlled setting, since
in the Coulomb phase the lattice theory must reproduce the perturbative
prediction. It turns out that on either side of the phase transition clear
differences show up and in the Coulomb phase the ability to remove double Dirac
sheets proves vital on a small lattice.Comment: 14 pages, 8 figures containing 23 graphs, v2: 2 figures removed, 2
references adde
Influence of phenolic acids on growth and inactivation of Oenococcus oeni and Lactobacillus hilgardii
Aims: To determine the effect of several wine-associated, phenolic acids on the growth and viability of strains of
Oenococcus oeni and Lactobacillus hilgardii.
Methods and Results: Growth was monitored in ethanol-containing medium supplemented with varying
concentrations of hydroxybenzoic acids (p-hydroxybenzoic, protocatechuic, gallic, vanillic and syringic acids) and
hydroxycinnamic acids (p-coumaric, caffeic and ferulic acids). Progressive inactivation was monitored in ethanolcontaining
phosphate buffer supplemented in a similar manner to the growth experiments. Hydroxycinnamic acids
proved to be more inhibitory to the growth of O. oeni than hydroxybenzoic acids. On the other hand, some acids
showed a beneficial effect on growth of Lact. hilgardii. p-Coumaric acid showed the strongest inhibitory effect on
growth and survival of both bacteria.
Conclusions: Most phenolic acids had a negative effect on growth of O. oeni, for Lact. hilgardii this effect was only
noted for p-coumaric acid. Generally, O. oeni was more sensitive to phenolic acid inactivation than Lact. hilgardii.
Significance and Impact of the Study: Eight wine-derived, phenolic acids were compared for their effects on
wine lactic acid bacteria. Results indicate that phenolic acids have the capacity to influence growth and survival
parameters. The differences found between phenolic compounds could be related to their different chemical
structures
Cell membrane damage induced by phenolic acids on wine lactic acid bacteria
The aim of this work was to investigate the effect of phenolic acids on cell membrane permeability of
lactic acid bacteria from wine. Several phenolic acids were tested for their effects on the cell membrane of
Oenococcus oeni and Lactobacillus hilgardii by measuring potassium and phosphate efflux, proton influx and
by assessing culture viability employing a fluorescence technique based on membrane integrity. The
experimental results indicate that hydroxycinnamic acids (p-coumaric, caffeic and ferulic acids) induce
greater ion leakages and higher proton influx than hydroxybenzoic acids (p-hydroxibenzoic, protocatechuic,
gallic, vanillic, and syringic acids). Among the hydroxycinnamic acids, p-coumaric acid showed the strongest
effect. Moreover, the exposure of cells to phenolic acids caused a significant decrease in cell culture viability,
as measured by the fluorescence assay, in both tested strains. The results agree with previous results
obtained in growth experiments with the same strains. Generally, phenolic acids increased the cell
membrane permeability in lactic acid bacteria from wine. The different effects of phenolic acids on
membrane permeability could be related to differences in their structure and lipophilic character
Ownership and control in a competitive industry
We study a differentiated product market in which an investor initially owns a controlling stake in one of two competing firms and may acquire a non-controlling or a controlling stake in a competitor, either directly using her own assets, or indirectly via the controlled firm. While industry profits are maximized within a symmetric two product monopoly, the investor attains this only in exceptional cases. Instead, she sometimes acquires a noncontrolling stake. Or she invests asymmetrically rather than pursuing a full takeover if she acquires a controlling one. Generally, she invests indirectly if she only wants to affect the product market outcome, and directly if acquiring shares is profitable per se. --differentiated products,separation of ownership and control,private benefits of control
Mortality prediction in chronic obstructive pulmonary disease comparing the GOLD 2015 and GOLD 2019 staging: a pooled analysis of individual patient data
In 2019, The Global Initiative for Chronic Obstructive Lung Disease (GOLD) modified the grading system for patients with COPD, creating 16 subgroups (1A-4D). As part of the COPD Cohorts Collaborative International Assessment (3CIA) initiative, we aim to compare the mortality prediction of the 2015 and 2019 COPD GOLD staging systems. We studied 17 139 COPD patients from the 3CIA study, selecting those with complete data. Patients were classified by the 2015 and 2019 GOLD ABCD systems, and we compared the predictive ability for 5-year mortality of both classifications. In total, 17139 patients with COPD were enrolled in 22 cohorts from 11 countries between 2003 and 2017; 8823 of them had complete data and were analysed. Mean +/- SD age was 63.9 +/- 9.8 years and 62.9% were male. GOLD 2019 classified the patients in milder degrees of COPD. For both classifications, group D had higher mortality. 5-year mortality did not differ between groups B and C in GOLD 2015; in GOLD 2019, mortality was greater for group B than C. Patients classified as group A and B had better sensitivity and positive predictive value with the GOLD 2019 classification than GOLD 2015. GOLD 2015 had better sensitivity for group C and D than GOLD 2019. The area under the curve values for 5-year mortality were only 0.67 (95% CI 0.66-0.68) for GOLD 2015 and 0.65 (95% CI 0.63-0.66) for GOLD 2019. The new GOLD 2019 classification does not predict mortality better than the previous GOLD 2015 system
Sex differences between women and men with COPD: A new analysis of the 3CIA study
Background: There is partial evidence that COPD is expressed differently in women than in men, namely on symptoms, pulmonary function, exacerbations, comorbidities or prognosis. There is a need to improve the characterization of COPD in females.
Methods: We obtained and pooled data of 17 139 patients from 22 COPD cohorts and analysed the clinical differences by sex, establishing the relationship between these characteristics in women and the prognosis and severity of the disease. Comparisons were established with standard statistics and survival analysis, including crude and multivariate Cox-regression analysis.
Results: Overall, 5355 (31.2%) women were compared with men with COPD. Women were younger, had lower pack-years, greater FEV1%, lower BMI and a greater number of exacerbations (all p < 0.05). On symptoms, women reported more dyspnea, equal cough but less expectoration (p < 0.001). There were no differences in the BODE index score in women (2.4) versus men (2.4) (p = 0.5), but the distribution of all BODE components was highly variable by sex within different thresholds of BODE. On prognosis, 5-year survival was higher in COPD females (86.9%) than in males (76.3%), p < 0.001, in all patients and within each of the specific comorbidities that we assessed. The crude and adjusted RR and 95% C.I. for death in males was 1.82 (1.69–1.96) and 1.73 (1.50–2.00), respectively.
Conclusions: COPD in women has some characteristic traits expressed differently than compared to men, mainly with more dyspnea and COPD exacerbations and less phlegm, among others, although long-term survival appears better in female COPD patients
An Integrated TCGA Pan-Cancer Clinical Data Resource to Drive High-Quality Survival Outcome Analytics
For a decade, The Cancer Genome Atlas (TCGA) program collected clinicopathologic annotation data along with multi-platform molecular profiles of more than 11,000 human tumors across 33 different cancer types. TCGA clinical data contain key features representing the democratized nature of the data collection process. To ensure proper use of this large clinical dataset associated with genomic features, we developed a standardized dataset named the TCGA Pan-Cancer Clinical Data Resource (TCGA-CDR), which includes four major clinical outcome endpoints. In addition to detailing major challenges and statistical limitations encountered during the effort of integrating the acquired clinical data, we present a summary that includes endpoint usage recommendations for each cancer type. These TCGA-CDR findings appear to be consistent with cancer genomics studies independent of the TCGA effort and provide opportunities for investigating cancer biology using clinical correlates at an unprecedented scale. Analysis of clinicopathologic annotations for over 11,000 cancer patients in the TCGA program leads to the generation of TCGA Clinical Data Resource, which provides recommendations of clinical outcome endpoint usage for 33 cancer types
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