93 research outputs found
Ionic liquid confined spaces controlled catalytic CO2 cycloaddition of epoxides in BMIm.ZnCl3 and its supported ionic liquid phases
Chemical fixation of CO2 to epoxides is an atom-economic and environment-benign approach to generate cyclic carbonates. Herein, we report efficient activation of the different aromatic and aliphatic epoxides at ambient reaction conditions. Our n-butyl-3-methylimidazulim trichlorozincate (BMIm.ZnCl3) ionic liquid presents higher activity with 56–95% conversion for the different aromatic and aliphatic epoxides from atmospheric pressure to 5 bar pressure at 40 ◦C. Small sized epoxides showed higher conversion and selectivity to cyclic carbonate as compared to bulky ones suggesting that the large epoxide substrates restricted diffusion into the confined spaces of BMIm.ZnCl3 IL, which limited the access of reactants to the catalytic active sites. By supporting the IL on the simple commercial SiO2, the confined SILP-ZnCl3 catalyst boosted the activity with maximum conversion and yield (99%) to cyclic carbonates under 10 bar at 100 ◦C. This higher performance could be attributed to the formation of the IL-cages onto SiO2 that enhances the local charge density and modulates the orientation of the IL near the surface to assist substantial charge transfer, leading to surface polarization and specific adsorption to ions. The reaction exemplifies a rare mechanism, supplemented by ex-situ ESI-MS analysis, in which epoxide ’O’ is strongly H-bonded to the C2-H of imidazolium cation, while the ZnCl3 anion acts as nucleophile to facilitate the ring opening without its dissociation in chloride anion and ZnCl2, contrasting to the previous reports
Cucurbits powdery mildew race identity and reaction of melon genotypes
Genetic resistance is one of the most suitable strategies to control cucurbit powdery mildew (CPM) on melon, incited by Podosphaera xanthii or Golovinomyces orontii. However, many races of these pathogens have been reported worldwide in recent years, what may compromise the effectiveness of this method. Thus, annual surveys of CPM races and the screening of germplasm for new sources of genetic resistance provide a vital support to melon breeding programs. This study aimed at identifying a natural population of CPM race under greenhouse conditions, as well as evaluating the reaction of local and exotic melon germplasm for CPM-resistance. CPM race identity was based on the reaction of eight race differentials: Védrantais, Nantais Oblong, PMR 45, PMR 5, WMR 29, Edisto 47, PI 414723 and PI 124111. Fifty-nine melon genotypes were evaluated, 53 of them being germplasm accessions, and six net melon elite-inbred lines, besides two net melon-type cultivars (Louis and Fantasy). Plants were evaluated using a visual scale for leaf lesions. The causal pathogen was confirmed to be P. xanthii, based on the presence of fibrosin bodies in conidia and the complete resistance response of winter melon (Benincasa hispida). Race 4 was identified for the first time in the São Paulo state, Brazil. Genotypes A19, A30, A32, C67, C384, JAB-3, JAB-7, JAB-9, JAB-11, JAB-18, JAB-20 and Solarking showed to be resistant to the race 4
Prospective study of ventricular function and myocardial deformation related to survival in acute Chagas disease: an experimental animal model
Chagas disease (CD) has been changing from an endemic Latino-American disease to a condition found outside endemic regions, due to migratory movements. Although often subclinical, its acute phase can be lethal. This study aimed to assess survival during the acute phase of CD and its relationship with ventricular function in an experimental model. To this end, 30 Syrian hamsters were inoculated with Trypanosoma cruzi (IG) and other 15 animals received saline solution (CG). Groups were monitored daily and submitted to echocardiography in two moments: before the challenge and 15 days post-infection. Left ventricular ejection fraction (LVEF) and global longitudinal myocardial strain (GLS) of the LV were measured. The IG was divided into groups of animals with and without clinical signs of disease. ANOVA for mixed models was used to compare ventricular function parameters. Survival analysis was studied using Kaplan-Meier curves and the log-rank test. The follow-up lasted 60 days. LVEF in IG was reduced through time (53.80 to 43.55%) compared to CG (57.86 to 59.73%) (p=0.002). There was also a reduction of GLS (−18.97% to −12.44%) in the IG compared to CG (p=0.012). Twelve animals from IG died compared to one animal from CG. Eleven out of the 12 animals from the IG group died before presenting with clinical signs of infection. Survival was reduced in the IG compared to CG over time (p=0.02). The reduced survival during the acute phase of this experimental model of Chagas disease was related to the significant reduction of LV function. The mortality rate in the IG was higher in the group presenting with clinical signs of infection
Estabilidade e adaptabilidade em linhagens de alface‑crespa por modelo misto REML/Blup
The objective of this work was to estimate the stability and genotypic adaptability of advanced lines and cultivars of curled green-leaf lettuce (Lactuca sativa), in different growing environments and seasons, using the REML/Blup mixed model. Ten genotypes, seven cropping environments, and two growing seasons were studied in 2015. Plant yield traits were evaluated, and data were subjected to the Selegen-REML/Blup software. Genotype stability and adaptability were analyzed using the harmonic mean of genotypic values (HMGV) and the relative performance of genotypic values (RPGV), respectively. The harmonic mean of RPGV (HMRPGV) was used to simultaneously estimate the stability, adaptability, and yield of breeding lines or cultivars. Considering the combined analysis of the two seasons for the set of traits, the lines L6, L7,and L8 were selected as promising ones and recommended for planting. The breeding lines selected for all season exhibit good yield and are considered superior to the commercial cultivars Vanda and Vera.O objetivo deste trabalho foi estimar a estabilidade e a adaptabilidade genotÃpica de linhagens avançadas e cultivares de alface-crespa (Lactuca sativa), em diferentes sistemas de cultivos e épocas, pelo modelo misto REML/Blup. Foram avaliados dez genótipos de alface, sete sistemas de cultivo e duas épocas, em 2015. Avaliaram-se os caracteres de produção das plantas, e os dados foram submetidos ao programa Selegen-REML/Blup. A estabilidade e a adaptabilidade genotÃpica foram analisadas pelos métodos da média harmônica dos valores genotÃpicos (MHVG) e do desempenho relativo dos valores genotÃpicos (PRVG), respectivamente. A média harmônica do PRVG (MHPRVG) foi utilizada para estimar simultaneamente a estabilidade, a adaptabilidade e a produtividade das linhagens e das cultivares. Ao se considerar a análise conjunta das duas épocas para o conjunto dos caracteres, as linhagens L6, L7 e L8 foram selecionadas como promissoras e recomendadas para plantio. As linhagens selecionadas para todas as épocas apresentam bons rendimentos e são consideradas superiores à s cultivares comerciais Vanda e Vera
Les droits disciplinaires des fonctions publiques : « unification », « harmonisation » ou « distanciation ». A propos de la loi du 26 avril 2016 relative à la déontologie et aux droits et obligations des fonctionnaires
The production of tt‾ , W+bb‾ and W+cc‾ is studied in the forward region of proton–proton collisions collected at a centre-of-mass energy of 8 TeV by the LHCb experiment, corresponding to an integrated luminosity of 1.98±0.02 fb−1 . The W bosons are reconstructed in the decays W→ℓν , where ℓ denotes muon or electron, while the b and c quarks are reconstructed as jets. All measured cross-sections are in agreement with next-to-leading-order Standard Model predictions.The production of , and is studied in the forward region of proton-proton collisions collected at a centre-of-mass energy of 8 TeV by the LHCb experiment, corresponding to an integrated luminosity of 1.98 0.02 \mbox{fb}^{-1}. The bosons are reconstructed in the decays , where denotes muon or electron, while the and quarks are reconstructed as jets. All measured cross-sections are in agreement with next-to-leading-order Standard Model predictions
Measurement of the J/ψ pair production cross-section in pp collisions at TeV
The production cross-section of J/ψ pairs is measured using a data sample of pp collisions collected by the LHCb experiment at a centre-of-mass energy of TeV, corresponding to an integrated luminosity of 279 ±11 pb. The measurement is performed for J/ψ mesons with a transverse momentum of less than 10 GeV/c in the rapidity range 2.0 < y < 4.5. The production cross-section is measured to be 15.2 ± 1.0 ± 0.9 nb. The first uncertainty is statistical, and the second is systematic. The differential cross-sections as functions of several kinematic variables of the J/ψ pair are measured and compared to theoretical predictions.The production cross-section of pairs is measured using a data sample of collisions collected by the LHCb experiment at a centre-of-mass energy of , corresponding to an integrated luminosity of . The measurement is performed for mesons with a transverse momentum of less than in the rapidity range . The production cross-section is measured to be . The first uncertainty is statistical, and the second is systematic. The differential cross-sections as functions of several kinematic variables of the pair are measured and compared to theoretical predictions
Measurement of forward production in collisions at TeV
A measurement of the cross-section for production in collisions is presented using data corresponding to an integrated luminosity of fb collected by the LHCb experiment at a centre-of-mass energy of TeV. The electrons are required to have more than GeV of transverse momentum and to lie between 2.00 and 4.25 in pseudorapidity. The inclusive production cross-sections, where the decays to , are measured to be \begin{align*} \begin{split} \sigma_{W^{+} \to e^{+}\nu_{e}}&=1124.4\pm 2.1\pm 21.5\pm 11.2\pm 13.0\,\mathrm{pb},\\ \sigma_{W^{-} \to e^{-}\bar{\nu}_{e}}&=\,\,\,809.0\pm 1.9\pm 18.1\pm\,\,\,7.0\pm \phantom{0}9.4\,\mathrm{pb}, \end{split} \end{align*} where the first uncertainties are statistical, the second are systematic, the third are due to the knowledge of the LHC beam energy and the fourth are due to the luminosity determination. Differential cross-sections as a function of the electron pseudorapidity are measured. The cross-section ratio and production charge asymmetry are also reported. Results are compared with theoretical predictions at next-to-next-to-leading order in perturbative quantum chromodynamics. Finally, in a precise test of lepton universality, the ratio of boson branching fractions is determined to be \begin{align*} \begin{split} \mathcal{B}(W \to e\nu)/\mathcal{B}(W \to \mu\nu)=1.020\pm 0.002\pm 0.019, \end{split} \end{align*} where the first uncertainty is statistical and the second is systematic.A measurement of the cross-section for production in collisions is presented using data corresponding to an integrated luminosity of fb collected by the LHCb experiment at a centre-of-mass energy of TeV. The electrons are required to have more than GeV of transverse momentum and to lie between 2.00 and 4.25 in pseudorapidity. The inclusive production cross-sections, where the decays to , are measured to be \begin{equation*} \sigma_{W^{+} \to e^{+}\nu_{e}}=1124.4\pm 2.1\pm 21.5\pm 11.2\pm 13.0\,\mathrm{pb}, \end{equation*} \begin{equation*} \sigma_{W^{-} \to e^{-}\bar{\nu}_{e}}=\,\,\,809.0\pm 1.9\pm 18.1\pm\,\,\,7.0\pm \phantom{0}9.4\,\mathrm{pb}, \end{equation*} where the first uncertainties are statistical, the second are systematic, the third are due to the knowledge of the LHC beam energy and the fourth are due to the luminosity determination. Differential cross-sections as a function of the electron pseudorapidity are measured. The cross-section ratio and production charge asymmetry are also reported. Results are compared with theoretical predictions at next-to-next-to-leading order in perturbative quantum chromodynamics. Finally, in a precise test of lepton universality, the ratio of boson branching fractions is determined to be \begin{equation*} \mathcal{B}(W \to e\nu)/\mathcal{B}(W \to \mu\nu)=1.020\pm 0.002\pm 0.019, \end{equation*} where the first uncertainty is statistical and the second is systematic.A measurement of the cross-section for W → eν production in pp collisions is presented using data corresponding to an integrated luminosity of 2 fb collected by the LHCb experiment at a centre-of-mass energy of TeV. The electrons are required to have more than 20 GeV of transverse momentum and to lie between 2.00 and 4.25 in pseudorapidity. The inclusive W production cross-sections, where the W decays to eν, are measured to be where the first uncertainties are statistical, the second are systematic, the third are due to the knowledge of the LHC beam energy and the fourth are due to the luminosity determination
Measurement of the B0s→μ+μ− Branching Fraction and Effective Lifetime and Search for B0→μ+μ− Decays
A search for the rare decays Bs0→μ+μ- and B0→μ+μ- is performed at the LHCb experiment using data collected in pp collisions corresponding to a total integrated luminosity of 4.4  fb-1. An excess of Bs0→μ+μ- decays is observed with a significance of 7.8 standard deviations, representing the first observation of this decay in a single experiment. The branching fraction is measured to be B(Bs0→μ+μ-)=(3.0±0.6-0.2+0.3)×10-9, where the first uncertainty is statistical and the second systematic. The first measurement of the Bs0→μ+μ- effective lifetime, τ(Bs0→μ+μ-)=2.04±0.44±0.05  ps, is reported. No significant excess of B0→μ+μ- decays is found, and a 95% confidence level upper limit, B(B0→μ+μ-)<3.4×10-10, is determined. All results are in agreement with the standard model expectations.A search for the rare decays and is performed at the LHCb experiment using data collected in collisions corresponding to a total integrated luminosity of 4.4 fb. An excess of decays is observed with a significance of 7.8 standard deviations, representing the first observation of this decay in a single experiment. The branching fraction is measured to be , where the first uncertainty is statistical and the second systematic. The first measurement of the effective lifetime, ps, is reported. No significant excess of decays is found and a 95 % confidence level upper limit, , is determined. All results are in agreement with the Standard Model expectations
Measurements of prompt charm production cross-sections in pp collisions at TeV
Production cross-sections of prompt charm mesons are measured using data from collisions at the LHC at a centre-of-mass energy of TeV. The data sample corresponds to an integrated luminosity of pb collected by the LHCb experiment. The production cross-sections of , , , and mesons are measured in bins of charm meson transverse momentum, , and rapidity, . They cover the rapidity range and transverse momentum ranges for and and for and mesons. The inclusive cross-sections for the four mesons, including charge-conjugate states, within the range of are determined to be \begin{equation*} \sigma(pp\rightarrow D^0 X) = 1190 \pm 3 \pm 64\,\mu\text{b} \end{equation*} \begin{equation*} \sigma(pp\rightarrow D^+ X) = 456 \pm 3 \pm 34\,\mu\text{b} \end{equation*} \begin{equation*} \sigma(pp\rightarrow D_s^+ X) = 195 \pm 4 \pm 19\,\mu\text{b} \end{equation*} \begin{equation*} \sigma(pp\rightarrow D^{*+} X)= 467 \pm 6 \pm 40\,\mu\text{b} \end{equation*} where the uncertainties are statistical and systematic, respectively.Production cross-sections of prompt charm mesons are measured using data from pp collisions at the LHC at a centre-of-mass energy of 5 TeV. The data sample corresponds to an integrated luminosity of 8.60 ± 0.33 pb collected by the LHCb experiment. The production cross-sections of D, D, D , and D mesons are measured in bins of charm meson transverse momentum, p, and rapidity, y. They cover the rapidity range 2.0 < y < 4.5 and transverse momentum ranges 0 < p < 10 GeV/c for D and D and 1 < p < 10 GeV/c for D and D mesons. The inclusive cross-sections for the four mesons, including charge-conjugate states, within the range of 1 < p < 8 GeV/c are determined to be where the uncertainties are statistical and systematic, respectively.Production cross-sections of prompt charm mesons are measured using data from collisions at the LHC at a centre-of-mass energy of TeV. The data sample corresponds to an integrated luminosity of pb collected by the LHCb experiment. The production cross-sections of , , , and mesons are measured in bins of charm meson transverse momentum, , and rapidity, . They cover the rapidity range and transverse momentum ranges for and and for and mesons. The inclusive cross-sections for the four mesons, including charge-conjugate states, within the range of are determined to be \sigma(pp\rightarrow D^0 X) = 1004 \pm 3 \pm 54\,\mu\text{b} \sigma(pp\rightarrow D^+ X) = 402 \pm 2 \pm 30\,\mu\text{b} \sigma(pp\rightarrow D_s^+ X) = 170 \pm 4 \pm 16\,\mu\text{b} \sigma(pp\rightarrow D^{*+} X)= 421 \pm 5 \pm 36\,\mu\text{b} where the uncertainties are statistical and systematic, respectively
Pathogenesis of chronic Chagas cardiomyopathy: the role of coronary microvascular derangements
There is ample experimental and clinical evidence of functional and structural microvascular abnormalities occurring in patients with Chagas cardiomyopathy, possibly due to the inflammatory process and/or autonomic disturbances caused by Trypanosoma cruzi infection. Those microvascular derangements are likely to constitute at least an ancillary factor that potentiates and amplifies the chronic inflammation in myocardial tissue. It is possible to devise appropriate therapeutic interventions aimed at reverting or slowing the progression of the microvascular abnormalities to positively affect the natural history of Chagas cardiomyopathy
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