[Show abstract][Hide abstract] ABSTRACT: One-dimensional ZnO nanorods were grown vertically on a (100) Si substrate using a vapor phase transport method. Following the fabrication of ZnO nanorods, Si layers were deposited by rapid thermal chemical vapor deposition (RTCVD) directly on the ZnO nanorod/Si (100) substrate. Field emission scanning electron microscopy revealed that a Si/ZnO nanorod coaxial heterostructure were synthesized vertically oriented along the (002) plane on a Si substrate. X-ray diffraction, Energy dispersive X-ray and Raman spectroscopy revealed that the ZnO nanorods were single crystals with a hexagonal structure, and grew with a c-axis orientation perpendicular to the Si substrate, whereas the Si layer was poly-silicon with cubic structure. These results demonstrated the Si/ZnO nanorod coaxial heterostructure were synthesized successfully on a (100) Si substrate and the ZnO nanorod enables the synthesis of a vertically grown well-aligned Si/ZnO coaxial nanorod heterostructure.
No preview · Article · Dec 2015 · Journal of Crystal Growth
[Show abstract][Hide abstract] ABSTRACT: This study aimed to examine clinical practice patterns in the management of pregnant women admitted with threatened preterm labor (TPL) in Korea.
Data from women admitted with a diagnosis of TPL were collected from 22 hospitals. TPL was defined as regular uterine contractions with or without other symptoms such as pelvic pressure, backache, increased vaginal discharge, menstrual-like cramps, bleeding/show and cervical changes. Data on general patient information, clinical characteristics at admission, use of tocolytics, antibiotics, and corticosteroids, and pregnancy outcomes were collected using an online data collections system.
A total of 947 women with TPL were enrolled. First-line tocolysis was administered to 822 (86.8%) patients. As a first-line tocolysis, beta-agonists were used most frequently (510/822, 62.0%), followed by magnesium sulfate (183/822, 22.3%), calcium channel blockers (91/822, 11.1%), and atosiban (38/822, 4.6%). Of the 822 women with first-line tocolysis, second-line tocolysis were required in 364 (44.3%). Of 364 with second-line, 199 had third-line tocolysis (37.4%). Antibiotics were administered to 29.9% of patients (284/947) with single (215, 22.7%), dual (26, 2.7%), and triple combinations (43, 4.5%). Corticosteroids were administered to 420 (44.4%) patients. Betamethasone was administered to 298 patients (71.0%), and dexamethasone was administered to 122 patients (29.0%).
Practice patterns in the management of TPL in Korea were quite various. It is needed to develop standardized practice guidelines for TPL management.
[Show abstract][Hide abstract] ABSTRACT: The size evolution of gold (Au) nanoparticles (NPs) on the sidewall surface of silicon (Si) nanowires (NWs) has been investigated by thermal treatments, using high-angle annular dark field scanning transmission electron microscopy. The Si NWs grown at 550°C by rapid thermal chemical vapour deposition have been observed to be surrounded by Au NPs with less than 5 nm diameter and ∼1012 cm-2 density on the whole Si NW surface. To explore the size change of Au NPs, the Au NPs on the Si NW were annealed ex situ at the temperature range of 700-900°C for 20 min. The sizes of NPs for samples annealed at 700, 800 and 900°C represent Gaussian distribution with the average size of 4, 6 and 7 nm, respectively, while at high temperatures above 900°C, they change to a bimodal distribution. It is suggested that the surface diffusion rate of Au NPs on Si NW is much lower than that on the Si substrate because of the substitutional diffusion mechanism.
No preview · Article · Mar 2015 · Micro & Nano Letters
[Show abstract][Hide abstract] ABSTRACT: To estimate the odds ratio of prepregnant body mass index (BMI), gestational weight gain (GWG), and gestational diabetes mellitus (GDM) for excessive fetal growth, which we define as large for gestational age (LGA).
We included 16,297 women who delivered a live-born singleton baby at term. We fit logistic regressions to estimate the odds ratios of variables, including maternal age, parity, prepregnant BMI ≥23, GWG ≥15 kg, and GDM, for LGA. We classified GWG into four categories (<10, 10-14.9, 15-19.9, and ≥20 kg) and BMI into four categories (underweight, normal, overweight, and obese). After adjusting for age and parity, we analyzed the odds ratios of prepregnant BMI according to GWG between non-GDM and GDM women for LGA.
The odds ratios of GWG ≥15 kg and prepregnancy BMI ≥23 for LGA were 2.40 (95% confidence interval [CI], 2.16-2.67) and 2.24 (95% CI, 1.99-2.51), respectively. The odd ratio of GDM was 1.37 (95% CI, 1.09-1.71). The risk of GDM women with normal/-overweight BMI and GWG <15 kg for LGA was not significantly greater than those of the reference group. The odd ratios of GDM women with overweight/obese BMI and GWG 15 to 19.9 kg were 3.95 (95% CI, 1.26-12.38) and 9.70 (95% CI, 3.79-24.87), respectively.
GWG ≥15 kg might be a more important risk factor for LGA than either prepregnancy BMI ≥23 or GDM. Risk for LGA was highest in obese GDM women with GWG ≥15 kg.
[Show abstract][Hide abstract] ABSTRACT: This study aimed to survey the current clinical practice of first-trimester ultrasonography among members of the Korean Society of Ultrasound in Obstetrics and Gynecology (KSUOG) and to provide basic data for making practical recommendations about first-trimester ultrasonography scan in Korea.
This survey was conducted using a self-administered anonymous questionnaire. The first-trimester in this survey was divided into two parts: early and late first-trimester. The survey was focused on safety issue, nuchal translucency (NT) cutoff, the anatomic structures they check, and the need for practical recommendations or educational courses during the first-trimester.
During the study period, 194 KSUOG members participated into this survey. The survey on early first-trimester scan reveal that 173 (89.2%) of respondents had used pulsed-wave Doppler or color Doppler imaging to monitor fetal heart beat. For the late first-trimester scan, 145 (74.7%) of respondents was found to check for fetal anatomical assessments during their NT screening performance; however, the clinical practice patterns were considerably varied among participants. More than half of the respondents used the criterion of NT ≥3.0 mm to define increased NT. Approximately 80% of respondents stated that the screening ultrasonography of fetal structures in the first-trimester was necessary. Furthermore, 187 (96.4%) of respondents were in favor of a recommendation for first-trimester ultrasonography in Korea.
This is the first survey of the current clinical practice of first-trimester ultrasonography in Korea. Our survey findings highlight the need for the practical recommendation or educational course for first-trimester ultrasonography.
[Show abstract][Hide abstract] ABSTRACT: Various fetal and maternal conditions are known to be associated with oligohydramnios. In general, oligohydramnios developed early in pregnancy is less common but frequently has a poor prognosis. The use of angiotensin-converting enzyme inhibitors or angiotensin receptor antagonists during pregnancy has been associated with oligohydramnios as well as growth restriction, pulmonary hypoplasia with respiratory distress, acute renal failure, cranial malformation and fetal death. Although many researchers report a use of oral hypoglycemic agents such as glyburide or metformin in gestational diabetes mellitus, but potential adverse effects of glimepiride, which is relatively recently developed, is not well known owing to the lack of clinical data, especially early in pregnancy. A 41-year-old woman with chronic hypertension and type 2 diabetes mellitus was treated with drugs including metformin, glimepiride and angiotensin receptor antagonist until approximately 20 weeks' gestations, when severe oligohydramnios was noted. After the hospitalization for bed rest, fetal surveillance, and discontinuation of the agents, amniotic fluid reaccumulated, and the infant was delivered at term. We report this case with a brief review of literatures.
[Show abstract][Hide abstract] ABSTRACT: The purpose of this study was to assess the characteristics of achondroplasia (ACH) diagnosed in fetuses or neonates and to evaluate the usefulness of a molecular genetic testing to confirm ACH.
[Show abstract][Hide abstract] ABSTRACT: This study was designed to determine the frequency and echocardiographic findings of 22q11.2 deletions in fetuses with cardiac defects on fetal ultrasound or familial backgrounds of 22q11.2 deletions.
[Show abstract][Hide abstract] ABSTRACT: Hydrogen effects on deep level defects and a defect generation in proton implanted Cu(In,Ga)Se2 (CIGS) based thin films for solar cell were investigated. CIGS films with a thickness of 3 μm were grown on a soda-lime glass substrate by a co-evaporation method, and then were implanted with protons. To study deep level defects in the proton implanted CIGS films, deep level transient spectroscopy measurements on the CIGS-based solar cells were carried out, these measurements found 6 traps (including 3 hole traps and 3 electron traps). In the proton implanted CIGS films, the deep level defects, which are attributed to the recombination centers of the CIGS solar cell, were significantly reduced in intensity, while a deep level defect was generated around 0.28 eV above the valence band maximum. Therefore, we suggest that most deep level defects in CIGS films can be controlled by hydrogen effects.
[Show abstract][Hide abstract] ABSTRACT: SiGe-on-Insulator (SGOI) structures were created using the Ge condensation method, where an oxidation process is performed on the SiGe/Si structure. This method involves rapid thermal chemical vapor deposition and H+/He+ ion-implantations. Deep level defects in these structures were investigated using deep level transient spectroscopy (DLTS) by varying the pulse injection time. According to the DLTS measurements, a deep level defect induced during the Ge condensation process was found at 0.28 eV above the valence band with a capture cross section of 2.67 × 10− 17 cm2, two extended deep levels were also found at 0.54 eV and 0.42 eV above the valence band with capture cross sections of 3.17 × 10− 14 cm2 and 0.96 × 10− 15 cm2, respectively. In the SGOI samples with ion-implantation, the densities of the newly generated defects as well as the existing defects were decreased effectively. Furthermore, the Coulomb barrier heights of the extended deep level defects were drastically reduced. Thus, we suggest that the Ge condensation method with H+ ion implantation could reduce deep level defects generated from the condensation and control the electrical properties of the condensed SiGe layers.
No preview · Article · Jun 2012 · Thin Solid Films
[Show abstract][Hide abstract] ABSTRACT: We report on rapid thermal chemical vapor deposition growth of silicon nanowires (Si NWs) that contain a high density of gold nanoclusters (Au NCs) with a uniform coverage over the entire length of the nanowire sidewalls. The Au NC-coated Si NWs with an antibody-coated surface obtain the unique capability to capture breast cancer cells at twice the highest efficiency currently achievable (~88% at 40 min cell incubation time) from a nanostructured substrate. We also found that irradiation of breast cancer cells captured on Au NC-coated Si NWs with a near-infrared light resulted in a high mortality rate of these cancer cells, raising a fine prospect for simultaneous capture and plasmonic photothermal therapy for circulating tumor cells.
[Show abstract][Hide abstract] ABSTRACT: The aim of this nested case-control study was to investigate the association between hepatocyte growth factor (HGF) concentrations in maternal plasma and the risk of developing preeclampsia.
[Show abstract][Hide abstract] ABSTRACT: Paracentric inversion of chromosome 18 is a rare cytogenetic abnormality. The vast majority of paracentric inversions are harmless and the offspring of paracentric inversion carriers have only slightly elevated risks for unbalanced karyotypes. However, various clinical phenotypes are seen due to breakpoint variation or recombination. We report a prenatally detected case of familial paracentric inversion of chromosome 18, inv(18)(q21.1q22), with normal clinical features.
[Show abstract][Hide abstract] ABSTRACT: Photoinduced current transient spectroscopy was used to investigate the defect states and capture kinetics of charge carriers for traps in low temperature polycrystalline silicon (poly-Si) films. A broad deep trap was found to be located 0.30 eV from the conduction band edge of poly-Si with capture cross section of 1.51× 10-15 cm2. The variation of the trap capture kinetics with filling pulse time showed extended traps and linear arrays of traps, which might be grain boundary defects. Proton implantation and H-plasma treatment were used to improve poly-Si device characteristics, with traps more effectively suppressed by the former treatment. The ionized hydrogen atoms implanted into the poly-Si films are imputed to amorphize the defective poly-Si film with post-annealing enhancing re-crystallization, resulting films with fewer defects.
No preview · Article · Dec 2010 · Japanese Journal of Applied Physics