Letteratura scientifica selezionata sul tema "Hf(0001)"

The first-principles method based on density function theory (DFT) is carried out to assess the effect of reactive elements (Hf and Y) on the interfacial adhesion. Our calculations predict that RE prefers to segregate on Al2O3(0001)/Fe (110) interface region, meanwhile the segregation of S to the interface is suppressed, which may be beneficial to improve the interface adhesion of the Al2O3(0001)/ Fe (110) interface. The strong p-d covalent coupling formed between O and Fe atoms across Al2O3(0001)/Fe (110) interfaces. Hf and Y form stronger chemical bonds with O atoms across Al2O3(0001)/Fe (110) interface than Fe. The formation of strong covalent RE-O bonds across the interface attributes to the increase of the interface adhesion. The population analysis can quantify the covalent bond strengths. The bond population values of Hf-O, Y-O bonds are larger than that of Fe-O bond, which hints at the mechanism by which RE strengthen the Al2O3(0001)/Fe (110) interface, and as a result, the oxidation resistance of FeCrAl alloys are improved.

Background: Reduction of 30-day all-cause readmissions for heart failure (HF) has become an important quality-of-care metric for health care systems. Many hospitals have implemented quality improvement programs designed to reduce 30-day all-cause readmissions for HF. Electronic medical record (EMR)-based measures have been employed to aid in these efforts, but their use has been largely adjunctive to, rather than integrated with, the overall effort. Objectives: We hypothesized that a comprehensive EMR-based approach utilizing an HF dashboard in addition to an established HF readmission reduction program would further reduce 30-day all-cause index hospital readmission rates for HF. Methods: After establishing a quality improvement program to reduce 30-day HF readmission rates, we instituted EMR-based measures designed to improve cohort identification, intervention tracking, and readmission analysis, the latter 2 supported by an electronic HF dashboard. Our primary outcome measure was the 30-day index hospital readmission rate for HF, with secondary measures including the accuracy of identification of patients with HF and the percentage of patients receiving interventions designed to reduce all-cause readmissions for HF. Results: The HF dashboard facilitated improved penetration of our interventions and reduced readmission rates by allowing the clinical team to easily identify cohorts with high readmission rates and/or low intervention rates. We significantly reduced 30-day index hospital all-cause HF readmission rates from 18.2% at baseline to 14% after implementation of our quality improvement program (P = .045). Implementation of our EMR-based approach further significantly reduced 30-day index hospital readmission rates for HF to 10.1% (P for trend = .0001). Daily time to screen patients decreased from 1 hour to 15 minutes, accuracy of cohort identification improved from 83% to 94.6% (P = .0001), and the percentage of patients receiving our interventions, such as patient education, also improved significantly from 22% to 100% over time (P < .0001). Conclusions: In an institution with a quality improvement program already in place to reduce 30-day readmission rates for HF, an EMR-based approach further significantly reduced 30-day index hospital readmission rates.

The growth and stability of hafnium films on [Formula: see text]-GaN(0001) surface with native oxide was investigated with X-ray and ultraviolet photoelectron spectroscopy (XPS, UPS). It is shown that hafnium creates a continuous and stable layer on GaN substrate. Thermal treatment at [Formula: see text]C of Hf/GaN system causes decomposition of GaN and reaction of hafnium with atomic nitrogen from the substrate. XPS spectra demonstrate the reaction by a strong shift of the N 1s and Hf 4f lines. An attempt for bringing on the same reaction with molecular nitrogen under pressure of [Formula: see text] mbar was not successful. UPS spectra show a metallic character of the hafnium adlayer in such instances.

Inflammation has been established to play a crucial role in the onset of heart failure (HF) for many years, and the systemic inflammation response index (SIRI) is a new and comprehensive indicator reflecting the inflammation status in human body. The aim of this investigation was to determine the potential relationship between HF and SIRI in adults. For this investigation, we used cross-sectional data from the National Health and Nutrition Examination Survey (NHANES), which was conducted from 2009 to 2018. The study utilized multivariable linear regression models to examine the potential independent relationship between HF and SIRI. Additionally, a subgroup analysis and interaction test were carried out. To illustrate the nonlinear relationship, threshold effect analysis and fitted smoothing curves were also used. 26,303 eligible subjects aged ≥ 20 years were enrolled as the final samples. HF participants exhibited significant higher SIRI compared with non-HF participants [1.89 ± 1.33 vs 1.25 ± 0.95 (1000 cells/μL), P < .0001]. Multivariate logistic regression showed that those in the highest SIRI quartile had a significantly greater risk of HF by 130% (OR = 2.30, 95% CI 1.41–3.76; P < .0001). In addition, nonlinear relationship between HF and SIRI with the inflection point of 2.2 (1000 cells/μL) was observed. According to our research, adult HF prevalence and SIRI are positively correlated. This implies that SIRI could be a valuable biomarker for determining HF risk in the clinic.

Abstract In this study, the performance of AlN (0001)/Hf (0001) interface, such as occupation characteristics and combined energy, were studied by using the first principles calculation package. In the AlN/Hf interface, the Al- and N-terminated interfaces have three stacking sites each (outermost top site, sub-outer top site, and hexagonal close-packed hollow site), comprising six different models. The most adhesion work occupies the N-terminal interface of the hcp-hollow site, and the interface energy was also the smallest and most stable, as well as a lower fracture work than the AlN/Ti interface. Moreover, the differential charge density were calculated, the partial density of states were plotted, and the bonding properties were discussed. Compared with other interfaces, the N-terminated interface with the hcp-hollow site exhibited more covalent characteristics; on the Al-terminated interface with the sub-outer top site, the Hf-Al metallic bond was formed. The most stable atomic occupation type in AlN/Hf interface is the hcp-hollow site of N atomic terminal.

Intervention studies have demonstrated that saturated fat increases total and LDL-cholesterol concentrations, and it is therefore recommended that the intake of high-fat dairy products be limited. However, observational studies have found an inverse relationship between the intake of dairy products and incidence of CVD. We aimed to study whether the Ca content of dairy products influences the effect of dairy fat on the lipid profile. The study had a randomised cross-over design. Subjects (n9) were randomised to one of the sequence of four isoenergetic 10 d diets: low Ca and low fat (LC/LF: approximately 700 mg Ca/d, 25 % of energy (fat); high Ca and LF (HC/LF: approximately 2800 mg Ca/d, 25 % of energy fat); LC and high fat (LC/HF: approximately 700 mg Ca/d, 49 E% fat); or HC and HF (approximately 2800 mg Ca/d, 49 E% fat). Blood variables were measured before and after each diet period, and faeces and urine were collected at the end of each diet period. A two-way ANOVA was used to examine the effect of Ca and fat intake. Independent of Ca intake, the HF diet increased the concentrations of total (9 %;P < 0·0001), LDL (14 %;P < 0·0001)- and HDL (13 %;P = 0·0002)-cholesterol compared with the LF diet. However, independent of fat intake, the HC diet decreased the concentrations of total (4 %;P = 0·0051) and LDL-cholesterol (10 %;P < 0·0001) but not HDL-cholesterol compared with the LC diet. In addition, total:HDL-cholesterol was decreased (5 %;P = 0·0299), and HDL:LDL was increased (12 %;P = 0·0097) by the HC diet compared with the LC diet. Faecal fat excretion was increased by both the HC (P < 0·0001) and HF (P = 0·0052) diets. In conclusion, we observed that dairy Ca seems to partly counteract the raising effect of dairy fat on total and LDL-cholesterol, without reducing HDL-cholesterol.

Introduction: Since the beginning of the COVID-19 pandemic in March 2020, an intimate relationship between this disease and cardiovascular diseases has been seen. However, few studies assess the development of heart failure during this infection. This study aims to determine the predisposing factors for the development of heart failure (HF) during hospital admission of COVID-19 patients. Methodology: A retrospective and multicenter study of patients with HF admitted for COVID-19 in 150 Spanish hospitals (SEMI-COVID-19 Registry). A bivariate analysis was performed to relate the different variables evaluated in patients developing heart failure during hospital admission. A multivariate analysis including the most relevant clinical variables obtained in bivariate analyses to predict the outcome of heart failure was performed. Results: A total of 16.474 patients hospitalized for COVID-19 were included (57.5% men, mean age 67 years), 958 of them (5.8%) developed HF during hospitalization. The risk factors for HF development were: age (odds ratio [OR]): 1.042; confidence interval 95% (CI 95%): 1.035–1.050; p < 0.001), atrial fibrillation (OR: 2.022; CI 95%: 1.697–2.410; p < 0.001), BMI > 30 kg/m2 (OR: 1.460 CI 95%: 1.230–1.733; p < 0001), and peripheral vascular disease (OR: 1.564; CI 95%: 1.217–2.201; p < 0.001). Patients who developed HF had a higher rate of mortality (54.1% vs. 19.1%, p < 0.001), intubation rate (OR: 2,36; p < 0.001), and ICU admissions (OR: 2.38; p < 0001). Conclusions: Patients who presented a higher risk of developing HF were older with cardiovascular risk factors. The risk factors for HF development were age, atrial fibrillation, obesity, and peripheral vascular disease. In addition, patients who developed HF more frequently required to be intubated or admitted to the ICU.

Background: Hepatic derangements and liver injury following the Fontan operation (FO) may progress in some cases to hepatic fibrosis (HF) and cirrhosis. The respective roles of transient elastography (TE) or FibroScan, shear wave elastography (SWE), and aspartate transaminase to platelet ratio index (APRI) in assessing liver stiffness (LS) and possible liver injury in these patients are unclear. Methods: Thirty-nine patients (31 males), mean age 11.8 ± 5.7 years, median 11 years (interquartile range: 7-14.7 years), undergoing the FO between November 2017 and December 2018 were included. Liver stiffness and HF assessment was done with TE, SWE, and APRI in the preoperative period and postoperatively at 3-, 6-, and 12-month interval. Results: The LS values increased over time (postoperative values at 3, 6, and 12 months) as compared to preoperative values by both FibroScan and SWE. The change in liver stiffness measurement (LSM) was statistically significant: LSM0 to LSM3 ( P ≤ .0001), LSM0 to LSM6 ( P ≤ .0001), and LSM0 to LSM12 ( P = .001). Similarly, significant changes were observed on SWE: SWE0 to SWE3 ( P ≤ .0001), SWE0 to SWE6 ( P ≤ .0001), and SWE0 to SWE12 ( P = .001). There was no significant change in the APRI values over time. Conclusion: Noninvasive methods such as FibroScan and SWE may be of use to assess LS in follow-up of patients undergoing the FO for early recognition of hepatic changes.

Scandate cathode as a thermionic electron emission material has attracted broad interest owing to its high electron emission capability. Despite the large number of studies on the electron emission of the scandate tungsten cathode, there is a lack of understanding of the performance of scandium oxide incorporated in other refractory metal matrix. In this work, by applying first-principles calculations, we study the role that Sc2O3 nanocluster plays in enhancing the electron emission of the Hf cathode (labeled as Sc2O3@Hf). We find that Sc2O3@Hf is both thermally and mechanically stable, exhibits complex surface structures, and possesses inverse relationship between surface energy and work function. Moreover, the work function of the Hf (0001) surface can be reduced to 3.50 eV due to the change in the vacuum level when Sc2O3 nanocluster is doped, while the work function of the Hf (10[Formula: see text]2) surface can be reduced to 3.39, 3.39, and 3.03 eV when doped with Sc2O3, Y2O3, and CeO2 clusters, respectively.

In this study, we developed aA novel abrasive-free polishing method called the catalyst-referred etching (CARE) has been developed. CARE can chemically remove SiC chemically with using an etching agent activated by a catalyst. Platinum and hydrofluoric (HF) acid are used for the planarization of SiC substrates as a catalyst and etchant, respectively. CARE can produce an atomically flat surface of 4H–SiC (0001) with a root-mean-square roughness of less than <0.1 nm, regardless of the cut-off angle. However, the mechanism of CARE has hasis not yet been clarified to date. In this study, to clarify the mechanism, KF and NH4F are added to the etchant to clarify the mechanism. The An investigation of removal rate revealeds that the removal rate is proportional to [HF]×([F^- ]+[〖HF_2〗^- ]), and it is shown that both the HF molecule and fluorine ions (F− and HF2−) arethe reactive species of the CARE process are both HF molecule and fluorine ions (F- and HF2-).

Quantum materials exhibit distinctive electronic, magnetic, and optical properties, including topologically protected surface states, strong spin-orbit coupling, and quantum confinement effects. These properties make them promising for next-generation technologies like quantum computing and spintronics.Two different experimental techniques, such as Angle-resolved photoemission spectroscopy (ARPES) and Resonant in-elastic X-ray scattering (RIXS), have been utilized to study the electronic structure of three quantum materials: Hafnium (0001), Monolayer WSe2 on Au, and (Ge(0.87)Mn(0.13)Te.For Hafnium (0001), Our theoretical predictions indicated the presence of Rashba-split surface states with significant spin-momentum locking, characterized by a strong d-character. Experimental ARPES measurements, conducted with both He lamp sources and synchrotron radiation, are in excellent agreement with the theoretical band structures. However, deviations such as additional flat bands due to surface contaminants and the absence of certain predicted surface states were observed. Furthermore, linear and circular dichroism experiments highlighted the sensitivity of electronic states to light polarization, elucidating the orbital character of surface bands.In the case of monolayer WSe2, large-area monolayers of WSe2 were exfoliated using a well-established template-stripped gold method using two different templates, Mica and Silicon. Both experimental (microARPES) and theoretical spectra of WSe2/Au showed a strong hybridization influencing the electronic states around the Brillouin zone centre at Gamma and of charge transfer between Au and WSe2, however unaffected at valence band maximum (VBM) K point. Further corroborated by core level spectra taken on different regions of the thickness of WSe2 on Au, a substrate interaction of the nature covalent like quasi bonding (CLQB) was revealed.RIXS measurements were carried out on multiferroicmaterial Ge(0.87)Mn(0.13)Te to fathom the effect of external electric and magnetic fields on dd excitations. By applying a 3.1 V electric field, RIXS measurements showed a clear change in dd excitations, indicating a response related to the ferroelectric order of the material. Theoretical simulations were performed using the Anderson Impurity Model (AIM) within the Quanty software framework. The theoretical spectra of XAS and RIXS are in good agreement with the experimental spectra for oh symmetry with a crystal field parameter (10Dq) of 0.4 eV
Les matériaux quantiques présentent des propriétés électroniques, magnétiques et optiques distinctives, telles que des états de surface protégés topologiquement, un couplage spin-orbite fort et des effets de confinement quantique. Ces propriétés en font des candidats prometteurs pour les technologies de prochaine génération, comme l'informatique quantique et la spintronique.Deux techniques expérimentales différentes, telles que la spectroscopie de photoémission résolue en angle (ARPES) et la diffusion résonante inélastique des rayons X (RIXS), ont été utilisées pour étudier la structure électronique de trois matériaux quantiques : Hafnium (0001), Monocouche de WSe2 sur Au, et Ge(0.87)Mn(0.13)Te.Pour le Hafnium (0001), nos prédictions théoriques ont indiqué la présence d’états de surface de type Rashba avec un verrouillage spin-moment significatif, caractérisés par un fort caractère d. Les mesures expérimentales ARPES, réalisées à l'aide de sources de lampe He et de rayonnement synchrotron, sont en excellent accord avec les structures de bandes théoriques. Cependant, des écarts ont été observés, tels que des bandes plates supplémentaires dues à des contaminants de surface et l'absence de certains états de surface prédits. De plus, les expériences de dichroïsme linéaire et circulaire ont mis en évidence la sensibilité des états électroniques à la polarisation de la lumière, élucidant ainsi le caractère orbital des bandes de surface.Dans le cas de la monocouche de WSe2, de grandes monocouches de WSe2 ont été exfoliées en utilisant une méthode bien établie d'or pelable avec deux différents gabarits, le mica et le silicium. Les spectres expérimentaux (microARPES) et théoriques de WSe2/Au ont montré une forte hybridation influençant les états électroniques autour du centre de la zone de Brillouin à Gamma et un transfert de charge entre Au et WSe2, cependant, non affectés au point K du maximum de la bande de valence (VBM). Confirmé davantage par les spectres de niveaux fondamentaux pris sur différentes régions d’épaisseur de WSe2 sur Au, une interaction avec le substrat de type liaison quasi-covalente (CLQB) a été révélée.Des mesures RIXS ont été effectuées sur le matériau multiferroïque Ge(0.87)Mn(0.13)Te pour approfondir l'effet des champs électriques et magnétiques externes sur les excitations dd. En appliquant un champ électrique de 3,1 V, les mesures RIXS ont montré un changement clair dans les excitations dd, indiquant une réponse liée à l'ordre ferroélectrique du matériau. Des simulations théoriques ont été réalisées en utilisant le modèle d'impureté d'Anderson (AIM) dans le cadre du logiciel Quanty. Les spectres théoriques de l'absorption des rayons X (XAS) et du RIXS sont en bon accord avec les spectres expérimentaux pour une symétrie oh avec un paramètre de champ cristallin (10Dq) de 0,4 eV

Artemisininas com atividade contra cepas K-1 de P. falciparum foram modeladas com o método HF/3-21G. Para identificar as principais características das artemisininas necessárias para suas atividades, mapas de MEP foram construídos e usados. Os estudos de PCA e HCA mostraram que as variáveis energia do HOMO-1, DM, Q1, BA e nCs são responsáveis pela separação entre compostos mais ativos e menos ativos. Um modelo PLS com três componentes principais explicando 89% do total de informações foi construído para 18/5 compostos no conjunto de treinamento/validação externa. Como aplicação, analisamos os mapas de MEP e testamos nosso modelo PLS para prever o log RA de 15 artemisininas cujos testes biológicos ainda não foram realizados.,