Articles de revues : « Hf(0001) »

1

Zhang, Guo Ying, et Jie Tang. « Effects of Reactive Elements (Hf and Y) on Adhesive Behaviour of Al₂O₃(0001)Fe(110) Interface : A First-Principles Study ». Applied Mechanics and Materials 778 (juillet 2015) : 100–104. http://dx.doi.org/10.4028/www.scientific.net/amm.778.100.

Texte intégral

Résumé :

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.

Styles APA, Harvard, Vancouver, ISO, etc.

2

Banerjee, Dipanjan, Christine Thompson, Charlene Kell, Rajesh Shetty, Yohan Vetteth, Helene Grossman, Aria DiBiase et Michael Fowler. « An informatics-based approach to reducing heart failure all-cause readmissions : the Stanford heart failure dashboard ». Journal of the American Medical Informatics Association 24, n^o 3 (19 décembre 2016) : 550–55. http://dx.doi.org/10.1093/jamia/ocw150.

Texte intégral

Résumé :

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.

Styles APA, Harvard, Vancouver, ISO, etc.

3

LEWANDKÓW, RAFAŁ, RADOSŁAW WASIELEWSKI et PIOTR MAZUR. « HAFNIUM AND NITROGEN INTERACTION AT Hf/GaN(0001) INTERFACE ». Surface Review and Letters 27, n^o 11 (5 août 2020) : 2050013. http://dx.doi.org/10.1142/s0218625x20500134.

Texte intégral

Résumé :

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.

Styles APA, Harvard, Vancouver, ISO, etc.

4

Wang, Xiao, Min Wang et Yishi Shen. « Higher systemic inflammation response index is associated with increased risk of heart failure in adults : An observational study ». Medicine 103, n^o 28 (12 juillet 2024) : e38625. http://dx.doi.org/10.1097/md.0000000000038625.

Texte intégral

Résumé :

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.

Styles APA, Harvard, Vancouver, ISO, etc.

5

Zhang, Chaoyang, Lixia Zhang et Ziming Zhuo. « Density functional theory study of AlN/Hf interface ». Journal of Physics : Conference Series 2419, n^o 1 (1 janvier 2023) : 012045. http://dx.doi.org/10.1088/1742-6596/2419/1/012045.

Texte intégral

Résumé :

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.

Styles APA, Harvard, Vancouver, ISO, etc.

6

Lorenzen, Janne K., et Arne Astrup. « Dairy calcium intake modifies responsiveness of fat metabolism and blood lipids to a high-fat diet ». British Journal of Nutrition 105, n^o 12 (31 janvier 2011) : 1823–31. http://dx.doi.org/10.1017/s0007114510005581.

Texte intégral

Résumé :

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.

Styles APA, Harvard, Vancouver, ISO, etc.

7

Méndez Bailón, Manuel, Noel Lorenzo Villalba, Jorge Garcia Onrubia, Manuel Rubio Rivas, Maria Victoria Nuñez Rodriguez, María de los Reyes Pascual Pérez, Carmen Díaz Pedroche et al. « Prognostic Factors Associated with Acute Heart Failure in Patients Admitted for COVID-19 : Analysis of the SEMI-COVID-19 Registry ». Journal of Clinical Medicine 12, n^o 14 (12 juillet 2023) : 4649. http://dx.doi.org/10.3390/jcm12144649.

Texte intégral

Résumé :

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.

Styles APA, Harvard, Vancouver, ISO, etc.

8

Talwar, Sachin, Vasubabu Gudala, Raja Joshi, DM Shalimar, Kumble Seetharama Madhusudhan, Mani Kalaivani et Shiv Kumar Choudhary. « Noninvasive Assessment of Liver Stiffness in Patients Undergoing the Fontan Procedure ». World Journal for Pediatric and Congenital Heart Surgery 11, n^o 5 (27 août 2020) : 572–77. http://dx.doi.org/10.1177/2150135120935418.

Texte intégral

Résumé :

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.

Styles APA, Harvard, Vancouver, ISO, etc.

9

Bai, Ling, Tingwei Li, Congyang Zhang, Haijun Zhang, Shuang Yang, Quan Li et Qiang Sun. « Enhancing the thermionic electron emission performance of hafnium with nanocluster doping ». Applied Physics Letters 121, n^o 6 (8 août 2022) : 061603. http://dx.doi.org/10.1063/5.0106790.

Texte intégral

Résumé :

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.

Styles APA, Harvard, Vancouver, ISO, etc.

10

Isohashi, Ai, Yasushi Sano, Takeshi Okamoto, Kazuma Tachibana, Kenta Arima, Kouji Inagaki, Keita Yagi, Shun Sadakuni, Yoshitada Morikawa et Kazuto Yamauchi. « Study on Reactive Species in Catalyst-Referred Etching of 4H–SiC using Platinum and Hydrofluoric Acid ». Materials Science Forum 740-742 (janvier 2013) : 847–50. http://dx.doi.org/10.4028/www.scientific.net/msf.740-742.847.

Texte intégral

Résumé :

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-).

Styles APA, Harvard, Vancouver, ISO, etc.

11

Guo, Ping, Qin Fang et Yan Wang. « Associations between varicose veins and heart failure : A genetic correlation and mendelian randomization study ». Medicine 103, n^o 20 (17 mai 2024) : e38175. http://dx.doi.org/10.1097/md.0000000000038175.

Texte intégral

Résumé :

Varicose veins and heart failure (HF) are increasingly prevalent. Although numbers of observational studies have indicated that varicose veins might contribute to the risk of HF, the causal relationship between them remains unclear due to the uncontrolled confounding factors and reverse causation bias. Therefore, this study aimed to explore the potential causal relationship between varicose veins and HF. Based on publicly released genome-wide association studies (GWAS), gene correlation was assessed using linkage disequilibrium score (LDSC) regression, and we conducted a two-sample Mendelian randomization (TSMR) analysis to infer the causal relationship. We performed the Inverse variance weighted (IVW) method as the primary analysis, and used Weighted median, MR-Egger, weighted mode, simple mode, and MR-pleiotropy residual sum and outlier (MR-PRESSO) methods to detect and correct for horizontal pleiotropy. LDSC revealed there was a positive genetic correlation between varicose veins and HF (rg = 0.1726184, Se = 0.04511803, P = .0001). The results of the IVW method indicated that genetically predicted varicose veins were associated with an increased risk of HF (odds ratio (OR) = 1.03; 95% confidence interval (CI): 1.01–1.06; P = .009). Our findings illustrated the significant causal effect of varicose veins on HF, suggesting that people with varicose veins might have a higher risk of HF. The results provided a novel and important perspective into the development mechanism of HF.

Styles APA, Harvard, Vancouver, ISO, etc.

12

Zeng, Lianlin, Shasha Fu, Hailan Xu, Lutao Zhu, Xiaomei Li, Kang Cheng, Yangan Li et Kehui Hu. « Sleep duration and heart failure risk : Insights from a Mendelian Randomization Study ». Medicine 103, n^o 37 (13 septembre 2024) : e39741. http://dx.doi.org/10.1097/md.0000000000039741.

Texte intégral

Résumé :

To investigate the causal relationship between sleep duration and heart failure (HF) in a European population. We focused on the continuous sleep duration of 460,099 European individuals as our primary exposure. Genome-wide significant single nucleotide polymorphisms (SNPs, n = 9851,867) linked to continuous sleep duration were adopted as instrumental variables. The outcome of interest was based on HF events in a European cohort (n = 977,323; with 930,014 controls and 47,309 cases). We employed a two-sample Mendelian randomization (MR) approach to infer causality between sleep duration and the incidence of HF. For validation purposes, an additional cohort of 336,965 European individuals diagnosed with insomnia was selected as a secondary exposure group. Using its SNPs, a subsequent two-sample MR analysis was conducted with the HF cohort to further corroborate our initial findings. Employing the MR methodology, we selected 57 SNPs that are associated with sleep duration, and 24 SNPs that are associated with insomnia as instrumental variables. We discerned a substantial association between genetically inferred sleep duration and HF risk (odds ratio: 0.61; 95% confidence interval: 0.47–0.78, P < .0001). Our subsequent analysis highlighted a pronounced increased HF risk associated with insomnia (odds ratio: 1.54; 95% confidence interval: 1.08–2.17, P < .02). These conclusions were further bolstered by consistent results from sensitivity analyses. Our study suggests a causal linkage between sleep duration and the onset risk of HF in the European population. Notably, shorter sleep durations were associated with a heightened risk of HF.

Styles APA, Harvard, Vancouver, ISO, etc.

13

IWAMI, M., N. HATTORI, T. FUJIMOTO, M. HIRAI, M. KUSAKA, T. MORII, H. WATABE et M. WATANABE. « STUDIES OF $4{\rm H}\mbox{--}{\rm SiC}(0001){\rm Si}(\sqrt3\times\sqrt3)$ AND (0001)C(3×3) SURFACES AND THEIR METALLIZATION PROCESS BY NI USING STM, AES AND LEED ». Surface Review and Letters 07, n^o 05n06 (octobre 2000) : 679–82. http://dx.doi.org/10.1142/s0218625x00000555.

Texte intégral

Résumé :

Several methods have been tried to prepare clean surfaces of 4H–SiC(0001)Si and C, whose surface atomic, or electronic, structures have been studied by LEED (low energy electron diffraction) STM (scanning tunneling microscopy) and AES (Auger electron spectroscopy). Some sequential chemical treatments, for example, agitation in an organic solvent and dipping in HF solution, followed by the heating of a SiC wafer in UHV (ultrahigh vacuum, below 10-7 Pa) at 950°C, gave either a [Formula: see text] or 3×3 superstructure, observed by LEED (low energy electron diffraction), for the SiC(0001) Si or C surface, respectively. An elongated NH4F treatment followed by a heat treatment in UHV at ~950°C gave a rather flat region to be investigated by STM, where a [Formula: see text] superstructure for the SiC(0001) Si surface has been observed. In the case of metal (Ni) atom deposition on SiC(0001) [Formula: see text] and (0001)C(3×3) surfaces, AES and LEED analysis have clarified that deposited metal atoms form islands up to ~5 Å. However, Ni atoms dispersed uniformly at the very beginning of the deposition, which means that the Ni overlayer piles up in layer followed by island growth mode.

Styles APA, Harvard, Vancouver, ISO, etc.

14

Zellmer, Lucas, Maroun Chedid, Appesh Mohandas, Holly Rodin, Katherine Diaz Vickery et Gautam R. Shroff. « Prevalence and Impact of Adverse Social and Behavioral Determinants of Health in Heart Failure : Analysis of a Safety-Net Population ». Journal of Health Care for the Poor and Underserved 35, n^o 2 (mai 2024) : 503–15. http://dx.doi.org/10.1353/hpu.2024.a928629.

Texte intégral

Résumé :

Abstract: Objective. To determine the impact of adverse social and behavioral determinants of health (SBDH) on health care use in a safety-net community hospital (SNCH) heart failure (HF) population. Methods. We performed a retrospective analysis of HF patients at a single SNCH between 2018–2019 (N= 4594). Results. At least one adverse SBDH was present in 21% of the study population. Patients with at least one adverse SBDH were younger (57 vs. 68 years), more likely to identify as Black (50% vs. 36%), be male (68% vs. 53%), and have Medicaid insurance (48% vs. 22%), p<.001. Presence of at least one adverse SBDH (homelessness, substance use, or incarceration) correlated with increased hospitalizations (2.3 vs 1.4/patient) and ED visits (5.1 vs 2.1/patient), p<.0001. Adverse SBDH were independent predictors of HF readmissions. Prescribing of guideline-directed medical therapy was similar among all patients. Conclusions. In a SNCH HF cohort, adverse SBDH predominantly afflict younger Black men on Medicaid and are associated with increased utilization.

Styles APA, Harvard, Vancouver, ISO, etc.

15

Jiang, Jiali, Bachtiar Erik Valentine, Jianxiong Lu et Peter Niemz. « Time dependence of the orthotropic compression Young’s moduli and Poisson’s ratios of Chinese fir wood ». Holzforschung 70, n^o 11 (1 novembre 2016) : 1093–101. http://dx.doi.org/10.1515/hf-2016-0001.

Texte intégral

Résumé :

Abstract The time dependency of the orthotropic compliance for Chinese fir wood [Cunninghamia lanceolata (Lamb.) Hook] has been investigated by performing compressive creep experiments in all orthotropic directions. Time evolution of the creep strain in the axial and lateral directions was recorded by means of the digital image correlation (DIC) technique, to determine the diagonal and nondiagonal elements of the viscoelastic compliance matrix. The results reveal the significant influence of time on the mechanical behavior. The orthotropic nature of the viscoelastic compliance is highlighted by the different time dependency of the Young’s moduli and the Poisson’s ratios obtained for the individual directions. Differences among the time-dependent stress-strain relationship determined at the 25, 50, and 75% stress levels indicate that the viscoelastic behavior of wood is also load-dependent. A Poisson’s ratio values, which are increasing with time in νLR, νLT, νRT, νTR, and decreasing in νRL and νTL, demonstrate that the creep strain is influenced by loading directions. The substantially different time dependency of the nondiagonal elements of the compliance matrix further reveals the orthotropic compliance asymmetry and emphasizes the complexity of the viscoelastic character of wood.

Styles APA, Harvard, Vancouver, ISO, etc.

16

Xin, Gao, Zhou Fan, Fu Zongying et Zhou Yongdong. « A study of pine resin in softwood by 1D and 2D time-domain NMR ». Holzforschung 74, n^o 9 (25 septembre 2020) : 839–52. http://dx.doi.org/10.1515/hf-2019-0001.

Texte intégral

Résumé :

AbstractTime-domain nuclear magnetic resonance (TD-NMR) is widely used in the investigation of wood-water relationship. However, some ambiguities between the NMR signals and the components in wood remain unresolved, particularly the effect of pine resin on NMR signals. To clarify these ambiguities and increase the use of TD-NMR in wood research, different sample treatment methods were studied, including air-drying, low-temperature vacuum-drying, diethyl ether extraction and moisture isothermal adsorption. The corresponding one-dimensional (1D) T1, T2 and two-dimensional (2D) T1-T2 correlation relaxation time distributions of radiata pine and Douglas fir samples were investigated. The NMR signals accounted for “longer relaxation-time components” below the fiber saturation point (FSP), but overlaped in parts of the 1D relaxation time distributions making it difficult to distinguish between pine resin and moisture. The 2D T1-T2 correlation relaxation time distributions produced a better distinction between pine resin and bound water. This distinction established a quantitative relationship between pine resin, moisture and 2D NMR signal amplitudes.

Styles APA, Harvard, Vancouver, ISO, etc.

17

Higaki, Ayano, Yui Kadowaki, Arata Yoshinaga et Keiji Takabe. « Xylan deposition and lignification in differentiating tension wood fibers in Mallotus japonicus (Euphorbiaceae) with multi-layered structure ». Holzforschung 75, n^o 1 (26 janvier 2021) : 1–12. http://dx.doi.org/10.1515/hf-2020-0001.

Texte intégral

Résumé :

AbstractXylan deposition and lignification processes were examined in tension wood fibers with gelatinous layers (G-layers) in Mallotus japonicus (Euphorbiaceae). The cell walls consisted of a multi-layered structure of S1 + S2 + G + n(L + G), where n indicates the number of repetitions (n = 0–3) and L indicates very thin lignified layers. The formation and lignification processes of the multi-layered structure of tension wood fibers were examined by light microscopy, ultraviolet microscopy, and transmission electron microscopy (TEM) following KMnO4 staining. The deposition of xylan was examined by immunoelectron microscopy with a monoclonal antibody (LM11). Immunolabelling of xylan appeared in lignified cell wall layers, except in the compound middle lamella (CML), i.e., the S1, S2, and L layers but not the G-layers. The density of LM11 xylan immunogold labeling in S2 layers increased during the formation of G-layers. This increase was due to the shrinkage of S2 layers during development rather than intrusive deposition of xylan through G-layers. Lignification of the CML, S1, and S2 layers proceeded during G-layer formation. The shrinkage of S2 layers occurred almost simultaneously with the lignification of the S2 layers during G-layer formation, suggesting that the S2 layers shrank with lignification.

Styles APA, Harvard, Vancouver, ISO, etc.

18

Hinnemann, Berit, et Emily A. Carter. « Adsorption of Al, O, Hf, Y, Pt, and S Atoms on α-Al2O3(0001) ». Journal of Physical Chemistry C 111, n^o 19 (mai 2007) : 7105–26. http://dx.doi.org/10.1021/jp068869c.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

19

Okamoto, Takeshi, Yasuhisa Sano, Hideyuki Hara, Kenta Arima, Keita Yagi, Junji Murata, Hidekazu Mimura et Kazuto Yamauchi. « Damage-Free Planarization of 2-Inch 4H-SiC Wafer Using Pt Catalyst Plate and HF Solution ». Materials Science Forum 600-603 (septembre 2008) : 835–38. http://dx.doi.org/10.4028/www.scientific.net/msf.600-603.835.

Texte intégral

Résumé :

We report a damage-free and efficient planarization process for silicon carbide (SiC) using platinum as a catalyst in hydrofluoric acid (HF) solution. In previous studies, 4H-SiC (0001) on-axis wafers were planarized by this process and an extremely flat surface was obtained. However, electronic device substrates require off-axis wafers. In the present study, 4H-SiC (0001) 8° off-axis Si-face wafers were planarized using a Pt catalyst plate and HF solution. In the first trial using these wafers, the surface roughness worsened and a diagonal pattern was observed by phase-shift interference microscopy. The pattern seemed to have been formed when the Pt plate morphology was transcribed onto the wafer. The removal rate of the 8° off-axis Si-face wafer is much greater than that of the on-axis Si-face wafer. Thus, we concluded that the use of a smoother catalyst plate would be necessary to obtain a smooth 8° off-axis Si-face wafer surface. Improving the Pt plate morphology by hand lapping also improved the surface roughness of the processed wafer as compared with the preprocessed surface. The maximum height of the surface irregularity (peak-to-valley, P-V) and root-mean-square roughness were improved to 0.513 nm and 0.044 nm, respectively, as determined by atomic force microscopy (2×2 μm2).

Styles APA, Harvard, Vancouver, ISO, etc.

20

Mazur, Piotr, et Leszek Markowski. « Oxygen Influence on the Growth of Thin Hf Films on the 6H-SiC(0001) Surfaces ». Surface and Interface Analysis 42, n^o 10-11 (9 septembre 2010) : 1561–65. http://dx.doi.org/10.1002/sia.3606.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

21

Kadoglou, Nikolaos P. E., Sjoerd Bouwmeester, Anouk G. W. de Lepper, Marloes C. de Kleijn, Ingeborg H. F. Herold, Arthur R. A. Bouwman, Ioannis Korakianitis, Tim Simmers, Franke A. L. E. Bracke et Patrick Houthuizen. « The Prognostic Role of Global Longitudinal Strain and NT-proBNP in Heart Failure Patients Receiving Cardiac Resynchronization Therapy ». Journal of Personalized Medicine 14, n^o 2 (8 février 2024) : 188. http://dx.doi.org/10.3390/jpm14020188.

Texte intégral

Résumé :

Background: We aimed to evaluate whether baseline GLS (global longitudinal strain), NT-proBNP, and changes in these after cardiac resynchronization therapy (CRT) can predict long-term clinical outcomes and the echocardiographic-based response to CRT (defined by 15% relative reduction in left ventricular end-systolic volume). Methods: We enrolled 143 patients with stable ischemic heart failure (HF) undergoing CRT-D implantation. NT-proBNP and echocardiography were obtained before and 6 months after. The patients were followed up (median: 58 months) for HF-related deaths and/or HF hospitalizations (primary endpoint) or HF-related deaths (secondary endpoint). Results: A total of 84 patients achieved the primary and 53 the secondary endpoint, while 104 patients were considered CRT responders and 39 non-responders. At baseline, event-free patients had higher absolute GLS values (p < 0.001) and lower NT-proBNP serum levels (p < 0001) than those achieving the primary endpoint. A similar pattern was observed in favor of CRT responders vs. non-responders. On Cox regression analysis, baseline absolute GLS value (HR = 0.77; 95% CI, 0.51–1.91; p = 0.002) was beneficially associated with lower primary endpoint incidence, while baseline NT-proBNP levels (HR = 1.55; 95% CI, 1.43–2.01; p = 0.002) and diabetes presence (HR = 1.27; 95% CI, 1.12–1.98; p = 0.003) were related to higher primary endpoint incidence. Conclusions: In HF patients undergoing CRT-D, baseline GLS and NT-proBNP concentrations may serve as prognostic factors, while they may predict the echocardiographic-based response to CRT.

Styles APA, Harvard, Vancouver, ISO, etc.

22

Nishitani, Keisuke, Hiroki Sakane, Azusa N. Hattori, Takeshi Okamoto, Kentaro Kawai, Junichi Uchikoshi, Yasuhisa Sano, Kazuto Yamauchi, Mizuho Morita et Kenta Arima. « Graphene Formation on 4H-SiC(0001) Surface Flattened by Catalyst-Assisted Chemical Etching in HF Solution ». ECS Transactions 41, n^o 6 (16 décembre 2019) : 241–48. http://dx.doi.org/10.1149/1.3629972.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

23

Isohashi, Ai, Yasuhisa Sano, Shun Sadakuni et Kazuto Yamauchi. « 4H-SiC Planarization Using Catalyst-Referred Etching with Pure Water ». Materials Science Forum 778-780 (février 2014) : 722–25. http://dx.doi.org/10.4028/www.scientific.net/msf.778-780.722.

Texte intégral

Résumé :

A novel abrasive-free polishing method called catalyst-referred etching (CARE) has been developed. CARE can be used to chemically planarize a silicon carbide (SiC) surface with an etching agent activated by a catalyst. Platinum (Pt) and hydrofluoric (HF) acid are used as the catalyst and etchant, respectively. CARE can produce an atomically flat and crystallographically highly ordered surface of 4HSiC (0001) with a root-mean-square roughness of less than 0.1 nm regardless of the cut-off angle. However, industrial use of CARE is difficult because of HF acid usage. In this study, pure water was investigated as an alternative etchant to HF acid. We examined CARE using pure water by applying it to the planarization of a 4HSiC substrate and observed a feasible performance. The removal mechanism is considered to be the dissociative adsorption of water molecules to the SiC bonds of the topmost Si atom, namely the hydrolysis of the back bond, and the catalysis of Pt is considered to enhance the reaction. CARE with pure water is expected to represent a breakthrough method for surface processing of SiC, and will be widely applied in industrial processes such as planarization after high temperature processing in device fabrication.

Styles APA, Harvard, Vancouver, ISO, etc.

24

Bow, J. S. « Analysis of co-deposited Ti-Hf thin film on (0001)6H-SiC by HREM, energy-selected and hollow-cone images ». Proceedings, annual meeting, Electron Microscopy Society of America 52 (1994) : 978–79. http://dx.doi.org/10.1017/s0424820100172620.

Texte intégral

Résumé :

Solid solution binary alloys are attractive for defect-free thin film semiconductor contacts because lattice matching can be obtained by composition adjustment, but chemical homogeneity is required. Highly composition sensitive energy-selected and hollow cone (HC) dark field imaging were evaluated for heterogeneity detection in Ti-Hf films using an Ω filter/Zeiss 912 TEM. Conventional HREM, which relatively insensitive to spatial composition variations in this case, was used to observe structural defects in the films near the interfaces.Thin films of pure Ti deposited via UHV electron beam evaporation at room temperature on n-type, vicinal (0001) 6H-SiC showed good epitaxy. This contact displayed rectifying characteristics. The interface was both structurally and chemically sharp. However, misfit dislocations at “stand off” positions were found, due to 4 % mismatch between the basal parameters of Ti and SiC. same column with Ti in the periodic table and has hexagonal crystal structure, but larger lattice parameter (aHf = 3.196 Å, and aTi = 2.950 Å). The Ti-Hf solid solution system obeys Vergard's law well, that is, the lattice parameters of this alloy change linearly with composition.

Styles APA, Harvard, Vancouver, ISO, etc.

25

Irokawa, Yoshihiro, Toshihide Nabatame, Tomomi Sawada, Manami Miyamoto, Hiromi Miura, Kazuhito Tsukagoshi et Yasuo Koide. « Communication—A Powerful Method to Improve Dielectric/GaN Interface Properties : A Dummy SiO₂ Process ». ECS Journal of Solid State Science and Technology 13, n^o 8 (1 août 2024) : 085003. http://dx.doi.org/10.1149/2162-8777/ad6fd2.

Texte intégral

Résumé :

We report a simple and effective method for improving dielectric/GaN interface properties. In the process, a 5 nm thick SiO2 layer was deposited onto a GaN(0001) substrate via plasma-enhanced atomic layer deposition, followed by annealing at 800 °C for 300 s under a flowing N2 atmosphere. The SiO2 layer was then removed using buffered HF solution, and Pt/Al2O3/GaN metal-oxide-semiconductor capacitors were fabricated on the substrate. Positive-bias stress tests revealed that the flat-band voltage shifts were substantially reduced for devices fabricated using this process, probably because of improved interface crystallinity. This method can also be applied to other dielectric/GaN systems.

Styles APA, Harvard, Vancouver, ISO, etc.

26

Park, Kyeeun, Navya Konindala, Navya Konindala, Pyi Phyo Aung et Leidy Plaza Enriquez. « ODP507 PREVALENCE OF CARDIOVASCULAR DISEASE IN PATIENTS WITH SUBCLINICAL HYPOTHYROISIM ». Journal of the Endocrine Society 6, Supplement_1 (1 novembre 2022) : A777—A778. http://dx.doi.org/10.1210/jendso/bvac150.1607.

Texte intégral

Résumé :

Abstract Introduction Thyroid hormones play an essential role in maintaining cardiovascular homeostasis. Experimental studies have revealed that subtle changes in thyroid hormone levels, as observed in subclinical hypothyroidism, have adverse effects on the cardiovascular system due to predisposition to endothelial dysfunction, dyslipidemia and direct effects of thyroid hormones on the myocardium. We conducted a retrospective cohort study to elicit the role of subclinical hypothyroidism as an independent risk factor for cardiovascular diseases. Methods We conducted a retrospective analysis of 3 years of the National Inpatient Sample (NIS) database, 2016 to 2018. Study populations were selected using ICD-10 diagnosis code. Discharge-level weight analysis was used to produce a national estimate. We conducted multivariate regression analysis to calculate odds ratio with STATA 17. Results During the study period, 106,970,745 study population met the inclusion criteria and 37,215 of subclinical hypothyroidism (SCH) patients were discharged. SCH patients tended to be more female (63.48% v 56.40%), older (mean age 58.22± 0.25 v 49.48 ± 0. 01), diabetic (24.84% v 21.47%) and obese (18.63% v 13.54%). Prevalence of hyperlipidemia and hypertension were similar in both SCH and non-SCH groups (3.75% v 3.24% and 29. 09% v 29.35% each). Caucasian patients were predominant in both groups with similar ethnicity distribution (62.26% v 64.96%). 3.56% of SCH patient had acute coronary artery syndromes (ACS), whereas 2.78% of non-SCH patients developed the ACS. For the patients without history of heart failure (HF), 2.54% of SCH patients developed new onset of HF, whereas 1.11% of non-SCH patients developed HF. After adjusting for age, sex, race and comorbid burden, SCH is not associated with ACS (p = 0.375) or Afib (p= 0.74) but associated with elevated risk for new onset of HF (OR 1.88, 1.62–2.18, p < 0. 0001). Conclusion Our study shows that subclinical hypothyroidism is not associated with higher rates of ACS or Atrial fibrillation, however it is associated with statistically significant higher risk of new onset HF. Further research needs to be done to determine subclinical hyperthyroidism as a potential risk factor for HF and assess the benefit of lower threshold for treating subclinical hypothyroidism in preventing or delaying the onset of HF in patients with associated cardiac risk factors. Presentation: No date and time listed

Styles APA, Harvard, Vancouver, ISO, etc.

27

Qin, Xiwen, Joseph Hung, Tiew-Hwa Katherine Teng, Tom Briffa et Frank M. Sanfilippo. « Long-Term Adherence to Renin–Angiotensin System Inhibitors and β-Blockers After Heart Failure Hospitalization in Senior Patients ». Journal of Cardiovascular Pharmacology and Therapeutics 25, n^o 6 (5 juin 2020) : 531–40. http://dx.doi.org/10.1177/1074248420931617.

Texte intégral

Résumé :

Aims: We investigated long-term adherence to renin–angiotensin system inhibitors (RASIs) and β-blockers, and associated predictors, in senior patients after hospitalization for heart failure (HF). Methods: A population-based data set identified 4488 patients who survived 60 days following their index hospitalization for HF in Western Australia from 2003 to 2008 with a 3-year follow-up. Their person-linked Pharmaceutical Benefits Scheme records identified medications dispensed during follow-up. Drug discontinuation was defined as the first break ≥90 days following the previous supply. Medication adherence was calculated using the proportion of days covered (PDC), with PDC ≥ 80% defined as being adherent. Multivariable logistic regression models were used to identify predictors of PDC < 80%. Results: In the cohort (57% male, mean age: 76.6 years), 77.4% were dispensed a RASI and 52.7% a β-blocker within 60 days postdischarge. Over the 3-year follow-up, 28% and 42% of patients discontinued RASI and β-blockers, respectively. Only 64.6% and 47.5% of RASI and β-blocker users, respectively, were adherent to their treatment over 3 years, with adherence decreasing over time (trend P < .0001 for RASI and trend P = .02 for β-blockers). Older age, increasing Charlson comorbidity score, chronic kidney disease, and chronic obstructive pulmonary disease were independent predictors of PDC < 80% for both drug groups. Conclusion: Among seniors hospitalized for HF, discontinuation gaps were common for RASI and β-blockers postdischarge, and long-term adherence to these medications was suboptimal. Where appropriate, strategies to improve long-term medication adherence are indicated in HF patients, particularly in elderly patients with comorbidities.

Styles APA, Harvard, Vancouver, ISO, etc.

28

Carpenter, R. W., Changhai Li et David J. Smith. « Transition alpha structure in beta-isomorphous Nb-Hf alloys ». Proceedings, annual meeting, Electron Microscopy Society of America 45 (août 1987) : 232–33. http://dx.doi.org/10.1017/s0424820100126068.

Texte intégral

Résumé :

Binary Nb-Hf alloys exhibit a wide bcc solid solution phase field at temperatures above the Hfα→ß transition (2023K) and a two phase bcc+hcp field at lower temperatures. The β solvus exhibits a small slope above about 1500K, suggesting the possible existence of a miscibility gap. An earlier investigation showed that two morphological forms of precipitate occur during the bcc→hcp transformation. The equilibrium morphology is rod-type with axes along <113> bcc. The crystallographic habit of the rod precipitate follows the Burgers relations: {110}||{0001}, <112> || <1010>. The earlier metastable form, transition α, occurs as thin discs with {100} habit. The {100} discs induce large strains in the matrix. Selected area diffraction examination of regions ∼2 microns in diameter containing many disc precipitates showed that, a diffuse intensity distribution whose symmetry resembled the distribution of equilibrium α Bragg spots was associated with the disc precipitate.

Styles APA, Harvard, Vancouver, ISO, etc.

29

Hino, Shiro, Tomohiro Hatayama, Naruhisa Miura, Tatsuo Ozeki et Eisuke Tokumitsu. « Low Temperature Deposition of HfO₂ Gate Insulator on SiC by Metalorganic Chemical Vapor Deposition ». Materials Science Forum 527-529 (octobre 2006) : 1079–82. http://dx.doi.org/10.4028/www.scientific.net/msf.527-529.1079.

Texte intégral

Résumé :

Low temperature deposition of HfO2 films on 4H-SiC(0001) substrates by pulse introduced metalorganic chemical vapor deposition (MOCVD) using tetrakis-diethylamido-hafnium [Hf[N(C2H5)2]4, (TDEAH)] and H2O has been investigated. HfO2 films with relatively low leakage current density of 10-4 A/cm2 were obtained even at a deposition temperature as low as 190 °C. We demonstrate that the HfO2/SiC interface, where the HfO2 was deposited at 190 °C, has lower interface state density than a typical thermally-grown SiO2/SiC interface. It is also shown by X-ray photoelectron spectroscopy (XPS) that the HfO2/SiC structure fabricated at 190 °C has lower SiOx count than the HfO2/SiC structure fabricated at 400 °C.

Styles APA, Harvard, Vancouver, ISO, etc.

30

Jiang, Nianxin, Bing Jiang, Xuan Zhang, Wei Yong et Shaowei Zhuang. « Evaluation of CORIN in patients with heart failure : A systematic review and meta-analysis ». European Journal of Inflammation 20 (janvier 2022) : 1721727X2211306. http://dx.doi.org/10.1177/1721727x221130650.

Texte intégral

Résumé :

Objectives: We aim to evaluate the association between CORIN and heart failure. Methods: This study used PubMed, EMBASE, Cochrane database, and China National Knowledge Database (CNKI) to search for CORIN-related full-text articles with heart failure patients. We drew forest plots, performed sensitivity and bias analyses based on the included data. Next, we used Review Manager 5.2 software to assess the heterogeneity among selected articles. Results: Our meta-analysis results showed there was significant relationship between CORIN and heart failure (HF). There was significant difference of CORIN between heart failure group and control group (MD = −293.88, 95% confidence interval [-380.26, −207.49], p < .00001; heterogeneity p < .0001, I2= 97%) and there was significant difference in CORIN between ischemic group and non-ischemic group (MD = 88.79, 95% confidence interval [70.46107.12], heterogeneity p < .000, p = 0.94, l2= 0%). In subgroup analysis, there were significant differences in three different HF levels. Limited publication bias was observed, and this study was robust. Conclusion: In short, the results showed that CORIN was closely related with heart failure and might be helpful in the diagnosis of heart failure.

Styles APA, Harvard, Vancouver, ISO, etc.

31

Hosoi, Takuji, Yusuke Uenishi, Yuki Nakano, Takashi Nakamura, Takayoshi Shimura et Heiji Watanabe. « Retarded Oxide Growth on 4H-SiC(0001) Substrates due to Sacrificial Oxidation ». Materials Science Forum 778-780 (février 2014) : 562–65. http://dx.doi.org/10.4028/www.scientific.net/msf.778-780.562.

Texte intégral

Résumé :

The impact of a sacrificial oxidation treatment on subsequent gate oxide formation on 4H-SiC(0001) substrates was investigated. Although x-ray photoelectron spectroscopy (XPS) analysis revealed that the SiC surface after removing a 40-nm-thick sacrificial oxide by diluted HF solution was almost identical to that of an as-grown epilayer, the subsequent dry O2 oxidation resulted in a thinner SiO2 layer for the sample with the sacrificial oxidation in the ultrathin film regime (~3 nm). The metal-oxide-semiconductor (MOS) capacitor with sacrificial oxidation also exhibited a larger frequency dispersion in capacitance-voltage (C-V) characteristics, indicating that interface property had been degraded. However, when the oxide thickness reached about 10 nm, there was no difference in frequency dispersion with and without sacrificial oxidation. This means that the SiO2 growth in the initial stage of oxidation was significantly affected by the sacrificial oxidation treatment.

Styles APA, Harvard, Vancouver, ISO, etc.

32

Cazzola, Mario, Rosangela Invernizzi, Gaetano Bergamaschi, Sonia Levi, Barbara Corsi, Erica Travaglino, Valeria Rolandi, Giorgio Biasiotto, Jim Drysdale et Paolo Arosio. « Mitochondrial ferritin expression in erythroid cells from patients with sideroblastic anemia ». Blood 101, n^o 5 (1 mars 2003) : 1996–2000. http://dx.doi.org/10.1182/blood-2002-07-2006.

Texte intégral

Résumé :

The sideroblastic anemias are characterized by ring sideroblasts, that is, red cell precursors with mitochondrial iron accumulation. We therefore studied the expression of mitochondrial ferritin (MtF) in these conditions. Erythroid cells from 13 patients with refractory anemia with ring sideroblasts (RARS) and 3 patients with X-linked sideroblastic anemia (XLSA) were analyzed for the distribution of cytoplasmic H ferritin (HF) and MtF using immunocytochemical methods. We also studied 11 healthy controls, 5 patients with refractory anemia without ring sideroblasts (RA), and 7 patients with RA with excess of blasts (RAEB). About one fourth of normal immature red cells, mostly proerythroblasts and basophilic erythroblasts, showed diffuse cytoplasmic positivity for HF, but very few were positive for MtF (0%-10%). Similar patterns were found in anemic patients without ring sideroblasts. In contrast, many erythroblasts from patients with sideroblastic anemia (82%-90% in XLSA and 36%-84% in RARS) were positive for MtF, which regularly appeared as granules ringing the nucleus. Double immunocytochemical staining confirmed the different cellular distribution of HF and MtF. There was a highly significant relationship between the percentage of MtF+ erythroblasts and that of ring sideroblasts (SpearmanR = 0.90; P < .0001). Reverse transcription-polymerase chain reaction studies demonstrated the presence of MtF mRNA in circulating reticulocytes of 2 patients with XLSA but not in controls. These findings suggest that most of the iron deposited in perinuclear mitochondria of ring sideroblasts is present in the form of MtF and that this latter might be a specific marker of sideroblastic anemia.

Styles APA, Harvard, Vancouver, ISO, etc.

33

Rui Teng Bo-Tao, LIU, QUAN Jie-Li, LANG Jia-Jian et Luo Meng-Fei. « A Density Functional Theory Study of HF Adsorption on the α-AlF₃(0001) Surface ». Acta Physico-Chimica Sinica 29, n^o 02 (2013) : 271–78. http://dx.doi.org/10.3866/pku.whxb201211301.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

34

Belyansky, Michael, et Michael Trenary. « Reflection adsorption infrared spectroscopy of the oxidation of thin films of boron and hafnium diboride grown on Hf(0001) ». Journal of Vacuum Science & ; Technology A : Vacuum, Surfaces, and Films 15, n^o 6 (novembre 1997) : 3065–68. http://dx.doi.org/10.1116/1.580848.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

35

Belyansky, Michael, et Michael Trenary. « Structure of Heteroepitaxial Thin Films of Hafnium Diboride Grown on a Hf(0001) Surface As Determined by Scanning Tunneling Microscopy ». Journal of Physical Chemistry B 104, n^o 50 (décembre 2000) : 11833–36. http://dx.doi.org/10.1021/jp002559r.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

36

Armitage, R., J. Suda et T. Kimoto. « Characterization of ZrB2(0001) surface prepared by ex situ HF solution treatment toward applications as a substrate for GaN growth ». Surface Science 600, n^o 7 (avril 2006) : 1439–49. http://dx.doi.org/10.1016/j.susc.2006.01.032.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

37

Benetti, Federico, Ernesto Pe�herrera, Teodoro Maldonado, Yan Duarte Vera, Valvanur Subramanian et Luis Geffner. « Direct Myocardial Implantation of Human Fetal Stem Cells in Heart Failure Patients : Long-term Results ». Heart Surgery Forum 13, n^o 1 (11 février 2010) : 31. http://dx.doi.org/10.1532/hsf98.20091130.

Texte intégral

Résumé :

Background: End-stage heart failure (HF) is refractory to current standard medical therapy, and the number of donor hearts is insufficient to meet the demand for transplantation. Recent studies suggest autologous stem cell therapy may regenerate cardiomyocytes, stimulate neovascularization, and improve cardiac function and clinical status. Although human fetal-derived stem cells (HFDSCs) have been studied for the treatment of a variety of conditions, no clinical studies have been reported to date on their use in treating HF. We sought to determine the efficacy and safety of HFDSC treatment in HF patients.Methods and Results: Direct myocardial transplantation of HFDSCs by open-chest surgical procedure was performed in 10 patients with HF due to nonischemic, nonchagasic dilated cardiomyopathy. Before and after the procedure, and with no changes in their preoperative doses of medications (digoxin, furosemide, spironolactone, angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, betablockers), patients were assessed for New York Heart Association (NYHA) class, performance in the exercise tolerance test (ETT), ejection fraction (EF), left ventricular end-diastolic dimension (LVEDD) via transthoracic echocardiography, performance in the 6-minute walk test, and performance in the Minnesota congestive HF test. All 10 patients survived the operation. One patient had a stroke 3 days after the procedure, and although she later recovered, she was unable to perform the follow-up tests. Another male patient experienced pericardial effusion 3 weeks after the procedure. Although it resolved spontaneously, the patient abandoned his control tests and died 5 months after the procedure. An autopsy of the myocardium suggested that new young cells were present in the cardiomyocyte mix. At 40 months, the mean (SD) NYHA class decreased from 3.4 0.5 to 1.33 0.5 (P = .001); the mean EF increased 31%, from 26.6% 4% to 34.8% 7.2% (P = .005); and the mean ETT increased 291.3%, from 4.25 minutes to 16.63 minutes (128.9% increase in metabolic equivalents, from 2.46 to 5.63) (P < .0001); the mean LVEDD decreased 15%, from 6.85 0.6 cm to 5.80 0.58 cm (P < .001); mean performance in the 6-minute walk test increased by 43.2%, from 251 113.1 seconds to 360 0 seconds (P = .01); the mean distance increased 64.4%, from 284.4 144.9 m to 468.2 89.8 m (P = .004); and the mean result in the Minnesota test decreased from 71 27.3 to 6 5.9 (P < .001).Conclusion: Although these initial findings suggest direct myocardial implantation of HFDSCs is feasible and improves cardiac function in HF patients at 40 months, more clinical research is required to confirm these observations.

Styles APA, Harvard, Vancouver, ISO, etc.

38

Koenig, Julian. « Pneumogastric (Vagus) Nerve Activity Indexed by Heart Rate Variability in Chronic Pain Patients Compared to Healthy Controls : A Systematic Review and Meta-Analysis ». Pain Physician 1;19, n^o 1;1 (14 janvier 2016) : E55—E78. http://dx.doi.org/10.36076/ppj/2016.19.e55.

Texte intégral

Résumé :

Background: A large body of scientific literature derived from experimental studies emphasizes the vital role of vagal-nociceptive networks in acute pain processing. However, research on vagal activity, indexed by vagally-mediated heart rate variability (vmHRV) in chronic pain patients (CPPs), has not yet been summarized. Objectives: To systematically investigate differences in vagus nerve activity indexed by timeand frequency-domain measures of vmHRV in CPPs compared to healthy controls (HCs). Study Design: A systematic review and meta-analysis, including meta-regression on a variety of populations (i.e., clinical etiology) and study-level (i.e., length of HRV recording) covariates. Setting: Not applicable (variety of studies included in the meta-analysis) Methods: Eight computerized databases (PubMed via MEDLINE, PsycNET, PsycINFO, Embase, CINAHL, Web of Science, PSYNDEX, and the Cochrane Library) in addition to a hand search were systematically screened for eligible studies based on pre-defined inclusion criteria. A metaanalysis on all empirical investigations reporting short- and long-term recordings of continuous time- (root-mean-square of successive R-R-interval differences [RMSSD]) and frequency-domain measures (high-frequency [HF] HRV) of vmHRV in CPPs and HCs was performed. True effect estimates as adjusted standardized mean differences (SMD; Hedges g) combined with inverse variance weights using a random effects model were computed. Results: CPPs show lower vmHRV than HCs indexed by RMSSD (Z = 5.47, P < .0001; g = -0.24;95% CI [-0.33, -0.16]; k = 25) and HF (Z = 4.54, P < .0001; g = -0.30; 95% CI [-0.44, -0.17]; k = 61).Meta-regression on covariates revealed significant differences by clinical etiology, age, gender, and length of HRV recording. Limitations: We did not control for other potential covariates (i.e., duration of chronic pain, medication intake) which may carry potential risk of bias. Conclusion(s): The present meta-analysis is the most extensive review of the current evidence on vagal activity indexed by vmHRV in CPPs. CPPs were shown to have lower vagal activity, indexed by vmHRV, compared to HCs. Several covariates in this relationship have been identified. Further research is needed to investigate vagal activity in CPPs, in particular prospective and longitudinal follow-up studies are encouraged. Key words: Vagus nerve, heart rate variability, chronic pain, irritable bowel syndrome, fibromyalgia, primary headache disorders, meta-analysis, systematic review

Styles APA, Harvard, Vancouver, ISO, etc.

39

Liu, Dongliang, et Min Chen. « Comparison of the outermost layer of MB2 (1 0 1¯ 0) and (0001) surfaces (M=Hf, Ta) : A first-principles investigation ». Materials Today Communications 17 (décembre 2018) : 474–79. http://dx.doi.org/10.1016/j.mtcomm.2018.10.009.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

40

Villacorta, Aline Sterque, Humberto Villacorta, José Antônio Caldas, Bernardo Campanário Precht, Pilar Barreto Porto, Letícia Ubaldo Rodrigues, Márcio Neves et al. « Effects of Heart Rate Reduction With Either Pyridostigmine or Ivabradine in Patients With Heart Failure : A Randomized, Double-Blind Study ». Journal of Cardiovascular Pharmacology and Therapeutics 24, n^o 2 (9 septembre 2018) : 139–45. http://dx.doi.org/10.1177/1074248418799364.

Texte intégral

Résumé :

Background: Heart rate (HR) reduction with ivabradine has been proved to reduce hospitalization and death from heart failure (HF). We sought to investigate whether pyridostigmine would effectively reduce HR in patients with chronic HF as compared with ivabradine. Methods: Twenty-one patients with HF who were in sinus rhythm with a resting HR over 70 bpm, despite optimal medical treatment, were included in a randomized, double-blind study comparing pyridostigmine versus ivabradine. The initial dose of ivabradine was 5 mg twice daily to reach a target HR between 50 and 60 bpm and could be titrated to a maximum of 7.5 mg twice daily. Pyridostigmine was used in a fixed dose of 30 mg 3 times daily. Results: The baseline HR for ivabradine and pyridostigmine groups was 89.1 (13.5) and 80.1 (7.2) bpm, respectively ( P = .083). After 6 months of treatment, HR was significantly reduced to 64.8 (8.3) bpm in the ivabradine group ( P = .0014) and 63.6 (5.9) bpm in the pyridostigmine group ( P = .0001). The N-terminal pro-B-type natriuretic peptide was reduced in the ivabradine group (median: 1308.4 [interquartile range: 731-1896] vs 755.8 [134.5-1014] pg/mL; P = .027) and in the pyridostigmine group (132.8 [89.9-829] vs 100.7 [38-360] pg/mL; P = .002). Inflammatory markers interleukin-1, interleukin-6, and tumor necrosis factor were reduced in both groups. Exercise capacity was improved in both groups, with increments in volume of oxygen utilization ([Formula: see text]O2; ivabradine: 13.1 vs 15.6, P = .048; pyridostigmine: 13.3 vs 16.7, P = .032). Heart rate recovery in the first minute postexercise was improved with pyridostigmine (11.8 [3.9] vs 18 [6.5]; P = .046), but not with ivabradine (13.3 [6.9] vs 14.1 [8.2]; P = .70). No differences in either group were observed in the myocardial scintigraphy with 123-iodine-metaiodobenzylguanidine. Conclusion: Both drugs significantly reduced HR, with improvements in exercise capacity and in neurohormonal and inflammatory profiles.

Styles APA, Harvard, Vancouver, ISO, etc.

41

Whitner, Jangus B., Nicole A. Fabiili, Jordan Siewart, Karen Akasaka et Anna Nelson. « Pharmacist-Led Provider Education on Inappropriate NSAID Prescribing Rates ». Family Medicine 52, n^o 8 (2 septembre 2020) : 592–96. http://dx.doi.org/10.22454/fammed.2020.147410.

Texte intégral

Résumé :

Background and Objectives: Nonsteroidal anti-inflammatory drugs (NSAIDs) are one of the most commonly used pain medications among US adults with about 70 million people regularly taking NSAIDs annually. Despite clear recommendations from current clinical practice guidelines and recent supporting literature, NSAIDs are continually prescribed inappropriately in patients with chronic kidney disease (CKD), hypertension (HTN), and heart failure (HF). The purpose of this project was to determine the impact of direct pharmacist-led education to providers on rates of inappropriate prescribing of NSAIDs in high-risk populations in a family medicine setting. Methods: This study included all adult (aged 18 years or older) patient charts with NSAIDs prescribed, refilled, or recorded within the specified time periods. We defined inappropriate orders as oral and of chronic duration (at least 90 days) with at least one high-risk International Classification of Diseases-10 chart diagnosis (HTN, HF, CKD). This was a single-center, retrospective chart review of prescribing rates during a 3-month period before and after provider education delivered by a pharmacist. Results: We identified a total of 325 charts from preintervention and 489 charts postintervention that met inclusion criteria. Of those, the charts with orders categorized as inappropriate were 90 versus 44, respectively. The rate of inappropriate prescribing of NSAIDs significantly decreased from 27.7% to 9.0% (P<.0001) postintervention. Among chronic NSAID users, both serum creatinine and systolic blood pressure significantly increased following NSAID initiation. Conclusions: A single pharmacist-led education intervention to primary care providers on inappropriate NSAID use in high-risk patient populations had a significant impact on minimizing inappropriate NSAID prescribing patterns within a family medicine outpatient office.

Styles APA, Harvard, Vancouver, ISO, etc.

42

Federico, Benetti, Geffner Luis, Duarte Yan et Peñaherrera Ernesto. « Surgical Fetal Stem Cell Transplant into Heart Failure Patients Long-term Results at 14 Years ». Journal of Stem Cell Therapy and Transplantation 9, n^o 1 (8 janvier 2025) : 001–5. https://doi.org/10.29328/journal.jsctt.1001045.

Texte intégral

Résumé :

Direct myocardial transplant of HFDSCs (human fetal derived stem cells) by open chest surgical procedure was performed in 10 patients with Heart Failure (HF) due to no ischemic, no chagasic dilated cardiomyopathy. All 10 patients survived the operation. At 40 months, the mean (±SD) NYHA class decreased from 3.4 ± 0.5 to 1.33 ± 0.5 (p = .001); the mean EF increased 31%, from 26.6% ± F) 34.8% ± 7.2% (p = .005); and the mean ETT increased 291.3%, from 4.25 minutes to 16.63 minutes (128.9% increase in metabolic equivalents, from 2.46 to 5.63) (p < .0001); the mean LVEDD decreased 15%, from 6.85 ± 0.6 cm to 5.80 ± 0.58 cm (p < .001); mean performance in the 6-minute walk test increased by 43.2%, from 251 ± 113.1 seconds to 360 0 seconds (p = .01); the mean distance increased 64.4%, from 284.4 144.9 m to 468.2 ± 89.8 m (p = .004); and the mean result in the Minnesota test decreased from 71 ± 27.3 to 6 ± 5.9 (p < .001). Six patients survived after 40 months; 5 of them had complete reverse remodeling after 3 months after transplants. The average age at the moment of the transplants was 62 years (s/d 11.6). Results: The first patient died at 5,4 years for an infection; the second patient died at,7,4 years for heart failure; the third patient died at 8,4 years for heart failure; the fourth patient died at 10 years for heart failure and the fifth patient died at 14,4 years after transplant at the age of 83 for heart failure. The average age at the moment of death was 70 years (s/d12.9). The survival rate at 4 years was 100% (K/M) and at 14 years (25%K/M). Conclusion: These initial worldwide experiences with the surgical direct transplant of liver fetal stem cells in patients with end-stage HF shows clearly the positive effect in the reverse remodeling of the left ventricle of 50% of the cohort and excellent long-term results in these types of patients opening a new avenue for treating end-stage HF patients without any other option of treatment.

Styles APA, Harvard, Vancouver, ISO, etc.

43

Qureshi, Muhammad Waqas, Xinxin Ma, Xinghong Zhang, Guangze Tang, Ramesh Paudel et Durga Paudyal. « Ab-initio predictions of phase stability, electronic structure, and optical properties of (0001)-MAX surfaces in M2AC (M = Cr, Zr, Hf ; A = Al, Ga) ». Journal of Physics and Chemistry of Solids 160 (janvier 2022) : 110338. http://dx.doi.org/10.1016/j.jpcs.2021.110338.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

44

Milas, Ivan, Berit Hinnemann et Emily A. Carter. « Diffusion of Al, O, Pt, Hf, and Y atoms on α-Al2O3(0001) : implications for the role of alloying elements in thermal barrier coatings ». J. Mater. Chem. 21, n^o 5 (2011) : 1447–56. http://dx.doi.org/10.1039/c0jm02212h.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

45

Niel Gardner, Devon O., Ayman Al-Halabi et Geert-Jan Kroes. « Efficient penetration of the basal plane (0001) face of ice Ih by HF at Ts=150 K : Dependence on incidence energy, incidence angle, and rotational energy ». Journal of Chemical Physics 120, n^o 24 (22 juin 2004) : 11796–803. http://dx.doi.org/10.1063/1.1753259.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

46

Bera, Lakshmi Kanta, Navab Singh, Ze Yu Chen, Calvin Chua Hung Ming, King Jien Chui, Ravinder Pal Singh, Yee Ye Sheng et al. « Multi-Layer High-K Gate Stack Materials for Low D<sub>it</sub> ; 4H-SiC Based MOSFETs ». Materials Science Forum 1062 (31 mai 2022) : 528–32. http://dx.doi.org/10.4028/p-oajc69.

Texte intégral

Résumé :

Metal-oxide-semiconductor capacitors with single and multi-layer high-K gate dielectrics on Si (0001) face of n-type 4H-SiC substrates have been investigated. Multi-layered nanolaminated gate-stack comprises alternating ultrathin (6nm) Al2O3 and HfO2. A 5nm thick interfacial silicon oxynitride is deposited prior to laminated films to investigate interface trap properties and tuning of flat band voltage. Total thickness of gate-stack films including interfacial layer is 55nm. The thermal stability of multi-layered nanolaminated film is investigated using XTEM. Localized crystallization of HfO2 is visible after RTA at 900°C while Al2O3 remains fully amorphous. Some of HfO2 grains have extended into Al2O3 layer but was not able to crossover. The measured accumulation capacitance of 55nm thick gate dielectric gives an effective dielectric constant value of 9.6 and an equivalent oxide thickness of 22nm from high-frequency capacitance-voltage measurements. A positive flat band voltage ( of 12.2V and 10.6V are observed from both single layer HfO2 and Al2O3 dielectrics, respectively due to presence of negatively charged oxygen interstitial defects generated during atomic layer deposition process. However, VFB shifted towards negative voltage-7.6V for multi-layered Al2O3/HfO2 stacks probably associated with positive Al and Hf interstitials at interface of Al2O3/HfO2. Ultrathin interfacial oxynitride films is effective to reduce Dit to 3×1011/eVcm2 and tuning of VFB. The breakdown field of stacked gate dielectric on 4H-SiC is 10.0 MV/cm.

Styles APA, Harvard, Vancouver, ISO, etc.

47

Cheng, Gong, Shengzhu Cao, Zhenzhen Zhang, Yuqing Xiong, Hui Zhou, Yanchun He, Kaifeng Zhang et Hengjiao Gao. « A First-principles study of HfB2 anisotropic surface stability and its oxygen adsorption behavior ». Modelling and Simulation in Materials Science and Engineering, 10 avril 2024. http://dx.doi.org/10.1088/1361-651x/ad3cfe.

Texte intégral

Résumé :

Abstract In this work, the HfB2 anisotropic surface stability, and the adsorption and diffusion behavior of oxygen molecule on the most likely exposed HfB2 surface were investigated based on density functional theory. The study found that the HfB2(0001) surface terminated by Hf (labeled as: Hf-(0001)) is more stable and more likely interact with oxygen. By rotating the oxygen molecule orientation and changing the adsorption site, all possible high and low-symmetry adsorption configurations are considered. The results show that the low symmetry structure is unstable, and eventually turn into the high symmetry ones. For the highly symmetric structures, oxygen molecule tends to be adsorbed in parallel, and the dissociated oxygen molecule tends to be located at the bridge and hollow site of the Hf-(0001) surface, and there is no energy barrier to this process. Charge density difference and Partial density of states proved that three absorbed structures present similar electronic interaction characteristics, and oxygen adsorption mainly affects the Hf atom at the outmost layer of the Hf-(0001) plane. Oxygen atoms bind to the Hf-(0001) surface mainly in the form of ionic bonds and covalent bonds, originating from the orbital hybridization of O-p and Hf-d. The oxidation of HfB2 starts from the interaction between oxygen and Hf.

Styles APA, Harvard, Vancouver, ISO, etc.

48

King, Sean W., Mark C. Benjamin, Richard S. Kern, Robert J. Nemanich et Robert F. Davis. « Ex Situ and In Situ Methods for Complete Oxygen and Non-Carbidic Carbon Removal from (0001)SI 6H-SiC Surfaces ». MRS Proceedings 423 (1996). http://dx.doi.org/10.1557/proc-423-563.

Texte intégral

Résumé :

AbstractComparisons between the wetting characteristics of (0001)si 6H-SiC and (111) Si surfaces in various acids and bases were made. It was found that 10:1 HF dipped Si (111) surfaces were hydrophobic where as the (0001)si 6H-SiC surfaces were hydrophilic. (0001)si 6H-SiC surfaces capped with a 20Å Si layer, however, were hydrophobic after HF dipping and exhibited outgassing levels on annealing which were several orders of magnitude lower than SiC wafers dipped in HF without the capping layer. Annealing the Si capped (0001)si 6H-SiC surfaces in UHV at 1100°C for 5 min. was found to be sufficient to thermally desorb the Si capping layer and produce a (3×3) Si rich, oxygen free (0001)si 6H-SiC surface.

Styles APA, Harvard, Vancouver, ISO, etc.

49

Belyansky, M., M. Trenary, S. Otani et T. Tanaka. « Comparison of the Hafnium Diboride(0001) and Hafnium(0001) Surfaces ». MRS Proceedings 441 (1996). http://dx.doi.org/10.1557/proc-441-463.

Texte intégral

Résumé :

AbstractThe surface properties of the (0001) surfaces of single crystals of hafnium and hafnium diboride are compared with a boride film deposited on the Hf(0001) surface. The surfaces were characterized with X-ray photoelectron spectroscopy (XPS) and low energy electron diffraction (LEED). Boron deposition was achieved through the thermal decomposition of diborane. The deposited boron reacts with the hafnium substrate to form HfB2 as determined by XPS and the HfB2 films were found to be epitaxial as determined by LEED. The epitaxial nature of the thin films was confirmed with X-ray diffraction. The epitaxial thin films of HfB2 on Hf(0001) display properties identical to those of the HfB2(0001) single crystal surface.

Styles APA, Harvard, Vancouver, ISO, etc.

50

Pressler, Susan J., Usha Subramanian, David Kareken, Susan M. Perkins, Irmina Gradus-Pizlo, Mary Jane Sauve, Rebecca Sloan, JinShil Kim, Yan Ding et Heather Jaynes. « Abstract 2718 : Cognitive Function is Poorer in Heart Failure ». Circulation 118, suppl_18 (28 octobre 2008). http://dx.doi.org/10.1161/circ.118.suppl_18.s_768-a.

Texte intégral

Résumé :

Background: Heart failure (HF) patients have been found to have cognitive deficits but studies have been limited by small samples and lack of comparison groups. Objective: To determine the types, frequency, and severity of cognitive deficits among patients (pts) with chronic HF compared to age- and education-matched healthy (HC) participants and participants with major medical conditions but not HF (MC). Methods: In this comparative study, face-to-face interviews were completed by 414 participants (249 HF pts, 63 HC, 102 MC) to assess function in cognitive domains of language, working memory, memory (verbal learning total and delayed recall), psychomotor speed, and executive function. Characteristics of HF pts were: mean age 62.9 yrs; 63% men; mean education 12.9 yrs; mean LVEF 28%; NYHA I-15%; II-34%; III-39%; IV-12%). HC and MC groups were matched on education and premorbid intellect, but HC were younger than HF and MC groups. Comparisons among the 3 groups were made using ANCOVA adjusting for intellect, age, and education. Family members of all participants were interviewed separately to validate cognitive deficits. Results: No differences were found among HF, HC and MC participants in language or working memory. In verbal learning total recall, HF pts had poorer scores than HC and MC participants (p<.0001). In delayed recall, HF pts had poorer scores than MC participants (p=.0152). In psychomotor speed, HF pts had poorer scores than HC and MC participants (p<.0001) on 1 test and poorer scores than MC (p=.0177) on the 2 nd . In executive function (verbal fluency and mental flexibility), HF pts had poorer scores than MC participants (p = .0022; p = .0428). Family member reported more difficulty in memory among HF pts (p< .0001) than HC ((p< .0001) and more negative behavior changes than HC (p=.0025) and MC participants (p=.0291). Conclusions: This carefully characterized sample of HF pts had poorer cognitive function than HC and MC participants. Domains most affected were memory, psychomotor speed processing, and executive function. Studies are needed to 1) evaluate the trajectory of cognitive function across the trajectory of HF; and 2) test novel interventions to improve cognitive function in HF.

Styles APA, Harvard, Vancouver, ISO, etc.

Articles de revues sur le sujet « Hf(0001) »

Créez une référence correcte selon les styles APA, MLA, Chicago, Harvard et plusieurs autres