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1.
Microsc Microanal ; 2024 May 04.
Article in English | MEDLINE | ID: mdl-38702984

ABSTRACT

Accurately controlling trace additives in dielectric barium titanate (BaTiO3) layers is important for optimizing the performance of multilayer ceramic capacitors (MLCCs). However, characterizing the spatial distribution and local concentration of the additives, which strongly influence the MLCC performance, poses a significant challenge. Atom probe tomography (APT) is an ideal technique for obtaining this information, but the extremely low electrical conductivity and piezoelectricity of BaTiO3 render its analysis with existing sample preparation approaches difficult. In this study, we developed a new APT sample preparation method involving W coating and heat treatment to investigate the trace additives in the BaTiO3 layer of MLCCs. This method enables determination of the local concentration and distribution of all trace elements in the BaTiO3 layer, including additives and undesired impurities. The developed method is expected to pave the way for the further optimization and advancement of MLCC technology.

2.
Cardiovasc Drugs Ther ; 32(4): 329-338, 2018 08.
Article in English | MEDLINE | ID: mdl-29956042

ABSTRACT

BACKGROUND/AIMS: The progression and development of congestive heart failure is still considered a large problem despite the existence of revascularization therapies and optimal, state-of-the-art medical services. An acute myocardial infarction (AMI) is a major cause of congestive heart failure, so researchers are investigating techniques to complement primary percutaneous coronary intervention (PCI) or thrombolytic therapy to prevent congestive heart failure after AMI. METHODS: Twenty-six patients with successful PCI for acute ST-segment elevation anterior wall myocardial infarction were assigned to either a control group (n = 12) or a bone marrow mesenchymal stem cells (BM-MSC) group (n = 14). The control group received optimum post-infarction treatment, and the BMSC group received intracoronary delivery of autologous BMSC at 1 month after PCI with the optimum medical treatment. The primary endpoint was a left ventricular ejection fraction (LVEF) change from baseline to 4-month follow-up, as determined via myocardial single-photon emission computed tomography (SPECT). RESULTS: The global LVEF at baseline (determined 3.5 ± 1.5 days after PCI) was 35.4 ± 3.0% in the control group and 33.6 ± 4.7% in the BM-MSC group. BMSC transfer enhanced left ventricular systolic function primarily in anterior wall myocardial segments adjacent to the LAD infarcted area. Four months later, via SPECT, global LVEF had increased by 4.8 ± 1.9% in the control group and 8.8 ± 2.9% in the BM-MSC group (p = 0.031). The cell transfer did not increase the risk of adverse clinical events, in-stent restenosis, or proarrhythmic effects. The echocardiographic evaluation also revealed a significant increase in the LVEF value from baseline to the 4-month (9.0 ± 4.7 and 5.3 ± 2.6%, p = 0.023) and 12-month (9.9 ± 5.2% and 6.5 ± 2.7%, p = 0.048) follow-up in the BM-MSC group but not in the control group. CONCLUSIONS: Intracoronary administration of autologous BM-MSC was tolerable and safe with significant improvement in LVEF at 4-month (SPECT and echocardiography result) and 12-month (echocardiography result only) follow-up in patients with anterior AMI.


Subject(s)
Anterior Wall Myocardial Infarction/surgery , Heart Failure/prevention & control , Mesenchymal Stem Cell Transplantation , ST Elevation Myocardial Infarction/surgery , Stroke Volume , Ventricular Function, Left , Aged , Anterior Wall Myocardial Infarction/complications , Anterior Wall Myocardial Infarction/diagnostic imaging , Anterior Wall Myocardial Infarction/physiopathology , Echocardiography , Female , Heart Failure/etiology , Heart Failure/physiopathology , Humans , Male , Mesenchymal Stem Cell Transplantation/adverse effects , Middle Aged , Percutaneous Coronary Intervention , Recovery of Function , Republic of Korea , Risk Factors , ST Elevation Myocardial Infarction/complications , ST Elevation Myocardial Infarction/diagnostic imaging , ST Elevation Myocardial Infarction/physiopathology , Time Factors , Tomography, Emission-Computed, Single-Photon , Treatment Outcome
3.
Sci Rep ; 6: 20794, 2016 Feb 08.
Article in English | MEDLINE | ID: mdl-26852801

ABSTRACT

Even though nanoscale analysis of magnetic properties is of significant interest, probing methods are relatively less developed compared to the significance of the technique, which has multiple potential applications. Here, we demonstrate an approach for probing various magnetic properties associated with eddy current, coil current and magnetic domains in magnetic inductors using multidimensional magnetic force microscopy (MMFM). The MMFM images provide combined magnetic responses from the three different origins, however, each contribution to the MMFM response can be differentiated through analysis based on the bias dependence of the response. In particular, the bias dependent MMFM images show locally different eddy current behavior with values dependent on the type of materials that comprise the MI. This approach for probing magnetic responses can be further extended to the analysis of local physical features.

4.
Yonsei Med J ; 43(2): 160-4, 2002 Apr.
Article in English | MEDLINE | ID: mdl-11971209

ABSTRACT

The goal of this study was to describe the overall genetic contribution of phenotypic variation to cardiovascular disease. The study population included 7,589 family members of 1,891 families, derived from Korean Medical Insurance Corporation. The risk factors considered were systolic blood pressure (SBP), diastolic blood pressure (DBP), body mass index (BMI), and high serum cholesterol. The levels of cardiovascular disease risk factors were adjusted for age, gender, smoking and alcohol drinking. Heritability was estimated from the slope of the line linear regression of offspring on mid-parent. All risk factors showed positive familial correlations, and correlations were generally lower for spouses than for parent- offspring pairs. Spouse correlations showed increasing patterns with age. Parents-offspring correlations showed little variation with age, suggesting that the observed correlations with CVD risk factors were primarily due to genetic influences rather than environmental effects. Estimated heritabilities were 26% for BMI, 26% for high serum cholesterol, 19% for SBP, and 9% for DBP. These results highlight the importance of considering genetic factors in studies of cardiovascular risk factors.


Subject(s)
Cardiovascular Diseases/genetics , Genetic Predisposition to Disease/genetics , Adult , Aged , Aged, 80 and over , Blood Pressure/genetics , Body Mass Index , Cholesterol/blood , Female , Humans , Male , Middle Aged , Risk Factors
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