232 research outputs found

    Presence of 3d Quadrupole Moment in LaTiO3 Studied by 47,49Ti NMR

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    Ti NMR spectra of LaTiO3 are reexamined and the orbital state of this compound is discussed. The NMR spectra of LaTiO3 taken at 1.5 K under zero external field indicate a large nuclear quadrupole splitting. This splitting is ascribed to the presence of the rather large quadrupole moment of 3d electrons at Ti sites, suggesting that the orbital liquid model proposed for LaTiO3 is inappropriate. The NMR spectra are well explained by the orbital ordering model expressed approximately as 1/3(dxy+dyz+dzx)1/\sqrt{3}(d_{xy}+d_{yz}+d_{zx}) originating from a crystal field effect. It is also shown that most of the orbital moment is quenched.Comment: 4 pages, 3 fugures; to appear in Phys. Rev. Let

    Comprehensive airborne characterization of aerosol from a major bovine source

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    We report an extensive airborne characterization of aerosol downwind of a massive bovine source in the San Joaquin Valley (California) on two flights during July 2007. The Center for Interdisciplinary Remotely-Piloted Aircraft Studies (CIRPAS) Twin Otter probed chemical composition, particle size distribution, mixing state, sub- and supersaturated water uptake behavior, light scattering properties, and the interrelationship between these parameters and meteorology. Total PM_(1.0) levels and concentrations of organics. nitrate. and ammonium were enhanced in the plume from the source as compared to the background aerosol. Organics dominated the plume aerosol mass (~56-64%), followed either by sulfate or nitrate. and then ammonium. Particulate amines were detected in the plume aerosol by a particle-into-liquid sampler (PILS) and via mass spectral inarkers in the Aerodvne C-ToF-AMS. Amines were found to be a significant atmospheric base even in the presence of arnmonia; particulate amine concentrations are estimated as at least 14-23% of that of ammonium in the plume. Enhanced sub- and supersaturated water uptake and reduced refractive indices were coincident with lower organic mass fractions, higher nitrate mass fractions, and the detection of amines. The likelihood of suppressed droplet growth owing to kinetic limitations from hydrophobic organic material is explored. After removing effects associated with size distribution and mixing state, the normalized activated fraction of cloud condensation nuclei (CCN) increased as a function of the subsaturated hygroscopic growth factor, with the highest activated fractions being consistent with relatively lower organic mass fractions and higher nitrate mass fractions. Subsaturated hygroscopic growth factors for the organic fraction of the aerosol are estimated based on employing the Zdanovskii-Stokes Robinson (ZSR) mixing rule. Representative values for a parameterization treating particle water uptake in both the sub- and supersaturated regimes are reported for incorporation into atmospheric models

    Equipamento experimental para determinação de isotermas de adsorção pelo método dinâmico

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    The evaluation of the performance of an experimental apparatus for the determination of flour sorption isotherms was carried out. To adjust the water activity - Aa - values (0.51; 0.57; 0.67; 0.75; 0.79 and 0.81) of the air stream, saturated salt solutions were used. The comparison of the apparatus with and without air recycling, was done by determining the sorption isotherm of soybean flour at 35°C. The air recycling model enables to obtain reliable data in a high Aa range, where samples are usually impaired by microbial growth when the other model is used. Time to obtain equilibrium for soybean flour with the air recycling model was about 50% less than for the model without air recycling.Foi realizada a avaliação do desempenho de equipamento experimental para a determinação de curvas de umidade de equilíbrio - isoterma de adsorção - de farinhas pelo método dinâmico. Para o ajuste dos valores definidos (0,51; 0,57; 0,67; 0,75; 0,79 e 0,81) de atividade de água - Aa - na corrente de ar, foram usadas soluções saturadas de sais. A comparação da eficiência do equipamento, com e sem recirculação de ar, foi feita determinando-se a isoterma de adsorção de farinha de soja a 35°C. A versão com recirculação de ar permite a obtenção de dados de equilíbrio em elevados níveis de Aa, nos quais há perda das amostras por crescimento microbiano quando se emprega a versão sem recirculação. Os tempos necessários para a obtenção do equilíbrio da farinha com as umidades relativas das correntes de ar são cerca de 50% menores na versão com recirculação de ar

    Sutureless Valve in Repeated Aortic Valve Replacement: Results from an International Prospective Registry

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    Objective: To report early and midterm results registry of patients undergoing repeated aortic valve replacement (RAVR) with sutureless prostheses from an international prospective registry (SURE-AVR). Methods: Between March 2011 and June 2019, 69 patients underwent RAVR with self-expandable sutureless aortic bioprostheses at 22 international cardiac centers.Results: Overall mortality was 2.9% with a predicted logistic EuroSCORE 11 of 10.7%. Indications for RAVR were structural valve dysfunction (84.1%) and infective prosthetic endocarditis (15.9%) and were performed in patients with previously implanted bioprostheses (79.7%), mechanical valves (15.9%), and transcatheter valves (4.3%). Minimally invasive approach was performed in 15.9% of patients. Rate of stroke was 1.4% and rate of early valve-related reintervention was 1.4%. Overall survival rate at 1 and 5 years was 97% and 91%, respectively. No major paravalvular leak occurred. Rate of pacemaker implantation was 5.8% and 0.9% per patient-year early and at follow-up, respectively. The mean transvalvular gradient at 1-year and 5-year follow-up was 10.5 mmHg and 11.5 mmHg with a median effective orifice area of 1.8 cm 2 and 1.8 cm 2 , respectively. Conclusions: RAVR with sutureless valves is a safe and effective approach and provides excellent clinical and hemodynamic results up to 5 years

    The Present State of the Use of Waste Wood Ash as an Eco-Efficient Construction Material: A Review

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    [EN] A main global challenge is finding an alternative material for cement, which is a major source of pollution to the environment because it emits greenhouse gases. Investigators play a significant role in global waste disposal by developing appropriate methods for its effective utilization. Geopolymers are one of the best options for reusing all industrial wastes containing aluminosilicate and the best alternative materials for concrete applications. Waste wood ash (WWA) is used with other waste materials in geopolymer production and is found in pulp and paper, wood-burning industrial facilities, and wood-fired plants. On the other hand, the WWA manufacturing industry necessitates the acquisition of large tracts of land in rural areas, while some industries use incinerators to burn wood waste, which contributes to air pollution, a significant environmental problem. This review paper offers a comprehensive review of the current utilization of WWA with the partial replacement with other mineral materials, such as fly ash, as a base for geopolymer concrete and mortar production. A review of the usage of waste wood ash in the construction sector is offered, and development tendencies are assessed about mechanical, durability, and microstructural characteristics. The impacts of waste wood ash as a pozzolanic base for eco-concreting usages are summarized. According to the findings, incorporating WWA into concrete is useful to sustainable progress and waste reduction as the WWA mostly behaves as a filler in filling action and moderate amounts of WWA offer a fairly higher compressive strength to concrete. A detail study on the source of WWA on concrete mineralogy and properties must be performed to fill the potential research gap.S

    Alternative c3 complement system : Lipids and atherosclerosis

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    Altres ajuts: Fundación Jesus SerraAltres ajuts: Fundación de Investigación CardiovascularAltres ajuts: Fondo Europeo de Desarrollo Regional (FEDER)Familial hypercholesterolemia (FH) is increasingly associated with inflammation, a phenotype that persists despite treatment with lipid lowering therapies. The alternative C3 complement system (C3), as a key inflammatory mediator, seems to be involved in the atherosclerotic process; however, the relationship between C3 and lipids during plaque progression remains unknown. The aim of the study was to investigate by a systems biology approach the role of C3 in relation to lipoprotein levels during atherosclerosis (AT) progression and to gain a better understanding on the effects of C3 products on the phenotype and function of human lipid-loaded vascular smooth muscle cells (VSMCs). By mass spectrometry and differential proteomics, we found the extracellular matrix (ECM) of human aortas to be enriched in active components of the C3 complement system, with a significantly different proteomic signature in AT segments. Thus, C3 products were more abundant in AT-ECM than in macroscopically normal segments. Furthermore, circulating C3 levels were significantly elevated in FH patients with subclinical coronary AT, evidenced by computed tomographic angiography. However, no correlation was identified between circulating C3 levels and the increase in plaque burden, indicating a local regulation of the C3 in AT arteries. In cell culture studies of human VSMCs, we evidenced the expression of C3, C3aR (anaphylatoxin receptor) and the integrin α β receptor for C3b/iC3b (RT-PCR and Western blot). C3mRNA was up-regulated in lipid-loaded human VSMCs, and C3 protein significantly increased in cell culture supernatants, indicating that the C3 products in the AT-ECM have a local vessel-wall niche. Interestingly, C3a and iC3b (C3 active fragments) have functional effects on VSMCs, significantly reversing the inhibition of VSMC migration induced by aggregated LDL and stimulating cell spreading, organization of F-actin stress fibers and attachment during the adhesion of lipid-loaded human VSMCs. This study, by using a systems biology approach, identified molecular processes involving the C3 complement system in vascular remodeling and in the progression of advanced human atherosclerotic lesions

    Clinical outcomes after implantation of a sutureless aortic bioprosthesis with concomitant mitral valve surgery: the SURE-AVR registry

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    Background: Early treatment of aortic valve stenosis is recommended in eligible symptomatic patients with severe aortic valve stenosis who would otherwise have a poor prognosis. The sutureless aortic valve bioprosthesis offers an alternative to standard aortic valve replacement with a sutured valve, but limited data are available in patients who have undergone multiple valve procedures involving the new, sutureless technology. We sought to investigate outcomes in high operative risk patients with previous or concomitant valve surgery who were implanted with a sutureless valve. Methods: SURE-AVR is an ongoing, prospective, multinational registry of patients undergoing aortic valve replacement. In-hospital and post-discharge outcomes up to 5 years were collected. Results: The study population comprised 78 patients (mean \ub1 SD: age 73.6 \ub1 7.6 years, logistic EuroSCORE 18.0 \ub1 17.5) enrolled at 13 sites who presented for concomitant or previous mitral valve repair (n\ua0= 45) or replacement (n\ua0= 33), with or without additional concomitant procedures, and were implanted with a sutureless valve. Mean \ub1 SD overall aortic cross-clamp time was 109 \ub1 41 min and cardiopulmonary bypass time was 152 \ub1 49 min. Mean \ub1 SD aortic pressure gradients decreased from 37.6 \ub1 17.7 mmHg preoperatively to 13.0 \ub1 5.7 mmHg at hospital discharge, and peak aortic pressure gradient from 61.5 \ub1 28.7 to 23.4 \ub1 10.6 mmHg. Early events included 1 death, 1 transient ischaemic attack, and 1 bleed (all 1.3%); a permanent pacemaker implantation was required in 6 patients (7.7%), and 2 reoperations (not valve related) (2.6%) took place. Over a median follow-up of 55.5 months (Q1 13.4, Q3 68.6), 12 patients died (6 cardiovascular and 6 non-cardiovascular, both 2.1% per patient-year). Five-year survival was 81.3%. Late paravalvular leak occurred in 2 patients (0.7% per patient-year) and permanent pacemaker implantation was required in 3 patients (0.1% per patient-year). There was no apparent rise in mean or peak aortic pressure gradient over the study. Conclusions: These results suggest that the sutureless implant is a technically feasible procedure during mitral surgery and is associated with good clinical outcomes

    Prevalence of Chromosomally Integrated Human Herpesvirus 6 in Patients with Human Herpesvirus 6–Central Nervous System Dysfunction

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    AbstractWe identified 37 hematopoietic cell transplantation recipients with human herpesvirus 6 (HHV-6) central nervous system dysfunction and tested donor-recipient pairs for chromosomally integrated HHV-6 (ciHHV-6). One patient had ciHHV-6A with possible HHV-6A reactivation and encephalitis. There was no ciHHV-6 enrichment in this group, but larger studies are needed to determine if patients with ciHHV-6 are at increased risk for HHV-6–associated diseases or other complications

    Assessing the Potential of Intra-specific Biodiversity towards Adaptation of Irrigated and Rain-fed Italian Production Systems to Future Climate

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    AbstractThe study addresses the biophysical dimension of adaptation. It illustrates and applies a framework to evaluate options for adaptation by identifying cultivars optimally adapted to expected climate conditions, building on existing crops intra-specific biodiversity. The aim is to reduce the vulnerability of current production systems without altering the pattern of current species and cultivation systems.Adaptability is assessed through a three-step approach that involves: 1) evaluation of indicators of expected thermal and hydrological conditions within the specific landscape and production system; 2) determination, for a set of cultivars, of cultivar- specific thermal and hydrological requirements to attain the desirable yield; 3) identification, as options for adaptation, of the cultivars for which expected climate conditions match the climatic requirements. The approach relies on a process-based simulation model of water flow in the soil-plant-atmosphere system for the calculation of hydrological indicators. Thermal indicators are derived by means of phenological models. Empirical functions of cultivars yield response to water availability are used to determine cultivar-specific hydrological requirements, whereas cultivars thermal requirements are estimated through phenological observations.In a future climate case (2021-2050) three case-studies are analyzed: 1) a system dominated by rain-fed crops (olive, winegrapes, durum wheat) in a hilly area of southern Italy; 2) irrigated fruit crops (peach, pear) in the Po Valley; 3) maize and tomato crop in an irrigated plain of southern Italy.Cultivars adapted to the future climate have been identified for rain-fed crops (e.g. 5 olive cvs). For irrigated crops we have evaluated adaptability for optimal and deficit irrigation schedules, accounting for site-specific soils hydrological properties. Options for adaptations have been identified as a combination of cultivars, soils and irrigation schedules (e.g 2 tomato cvs and 3 maize hybrids have been identified as options for adaptation at scarce water availability). Moreover, in the case of fruit crops, accounting for phenological changes highlighted the impact on irrigation water requirements of the interaction between phenology and the intra-annual distribution of precipitation
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