Enhanced Crystallinity of Epitaxial Graphene Grown on Hexagonal SiC Surface with Molybdenum Plate Capping

The crystallinity of epitaxial graphene (EG) grown on a Hexagonal-SiC substrate is found to be enhanced greatly by capping the substrate with a molybdenum plate (Mo-plate) during vacuum annealing. The crystallinity enhancement of EG layer grown with Mo-plate capping is confirmed by the significant change of measured Raman spectra, compared to the spectra for no capping. Mo-plate capping is considered to induce heat accumulation on SiC surface by thermal radiation mirroring and raise Si partial pressure near surface by confining the sublimated Si atoms between SiC substrate and Mo-plate, which would be the essential contributors of crystallinity enhancementclose0

Effects of maternal education on diet, anemia, and iron deficiency in Korean school-aged children

<p>Abstract</p> <p>Background</p> <p>We investigated the relationship among socioeconomic status factors, the risk of anemia, and iron deficiency among school-aged children in Korea.</p> <p>Methods</p> <p>The sample consisted of fourth-grade students aged 10 y recruited from nine elementary schools in Korean urban areas in 2008 (<it>n </it>= 717). Anthropometric and blood biochemistry data were obtained for this cross-sectional observational study. Anemia was defined as hemoglobin levels lower than 11.5 g/dl. Iron deficiency was defined as serum iron levels lower than 40 ug/dl. We also obtained data on parental education from questionnaires and on children's diets from 3-day food diaries. Parental education was categorized as low or high, with the latter representing an educational level beyond high school.</p> <p>Results</p> <p>Children with more educated mothers were less likely to develop anemia (<it>P </it>= 0.0324) and iron deficiency (<it>P </it>= 0.0577) than were those with less educated mothers. This group consumed more protein (<it>P </it>= 0.0004) and iron (<it>P </it>= 0.0012) from animal sources than did the children of less educated mothers, as reflected by their greater consumption of meat, poultry, and derivatives (<it>P </it>< 0.0001). Logistic regression analysis revealed a significant inverse relationship between maternal education and the prevalence of anemia (odds ratio: 0.52; 95% confidence interval: 0.32, 0.85).</p> <p>Conclusions</p> <p>As a contributor to socioeconomic status, maternal education is important in reducing the risk of anemia and iron deficiency and in increasing children's consumption of animal food sources.</p

25th annual computational neuroscience meeting: CNS-2016

The same neuron may play different functional roles in the neural circuits to which it belongs. For example, neurons in the Tritonia pedal ganglia may participate in variable phases of the swim motor rhythms [1]. While such neuronal functional variability is likely to play a major role the delivery of the functionality of neural systems, it is difficult to study it in most nervous systems. We work on the pyloric rhythm network of the crustacean stomatogastric ganglion (STG) [2]. Typically network models of the STG treat neurons of the same functional type as a single model neuron (e.g. PD neurons), assuming the same conductance parameters for these neurons and implying their synchronous firing [3, 4]. However, simultaneous recording of PD neurons shows differences between the timings of spikes of these neurons. This may indicate functional variability of these neurons. Here we modelled separately the two PD neurons of the STG in a multi-neuron model of the pyloric network. Our neuron models comply with known correlations between conductance parameters of ionic currents. Our results reproduce the experimental finding of increasing spike time distance between spikes originating from the two model PD neurons during their synchronised burst phase. The PD neuron with the larger calcium conductance generates its spikes before the other PD neuron. Larger potassium conductance values in the follower neuron imply longer delays between spikes, see Fig. 17.Neuromodulators change the conductance parameters of neurons and maintain the ratios of these parameters [5]. Our results show that such changes may shift the individual contribution of two PD neurons to the PD-phase of the pyloric rhythm altering their functionality within this rhythm. Our work paves the way towards an accessible experimental and computational framework for the analysis of the mechanisms and impact of functional variability of neurons within the neural circuits to which they belong

Reducing Particulates and Gaseous Emissions through Fuel Switching from Coal to Wood Pellets at Power Plants in South Korea during 2005 to 2022

This study analyzed the particulates and gaseous emissions from 2005 to 2022 for power plants in South Korea (Utility scale: 125 MW (B-1) and 200 MW (B-2), respectively), which recently successfully converted from coal to wood pellets. The analysis showed that (1) NOx reduction was 78.9 to 90.0% (with outlet denitrification facility), (2) SOx reduction was 95.0 to 99.6% (without desulfurization facility condition), and (3) total suspended particles (TSP) reduction was 70.3 to 87.2% (with improved filtration and dust collection facility). This research confirmed the capabilities of wood pellets as a baseload power source and demonstrated their superior NOx reduction compared to coal. In the case of SOx, the desulfurization facility was discontinued at the stage of the fuel switch, so the value was affected by exogenous variable factors other than fuel. The TSP appears to be a combination of the ‘fine dust' contained in the wood pellets and the performance of the filtration dust collector. The results suggest that fuel switching to wood pellets is a viable alternative to fossil fuels as an appropriate climate technology

Apprenticeships in Korea

행사명 : Korea Research Institute for Vocational Education and Trainin

A Survey on Perceptions of the Direction of Korean Medicine Education and National Licensing Examination

Recent changes in medical education and assessment led to a focus on occupational competency, and this study investigated the perceptions of Korean medicine doctors (KMDs) on the national licensing examination for KMDs (NLE-KMD). The survey aimed to understand KMDs’ recognition of the current situation, items to improve, and items to emphasize in the future. We conducted the web-based survey from 22 February to 4 March 2022, and 1244 among 23,338 KMDs answered voluntarily. Through this study, we found the importance of competency-related clinical practice and Korean standard classification of disease (KCD), and the presence of a generation gap. KMDs considered clinical practice (clinical tasks and clinical work performance) and the item related to the KCD important. They valued (1) the focus on KCD diseases that are frequently seen in clinical practice and (2) the readjustment and introduction of the clinical skills test. They also emphasized KCD-related knowledge and skills for the assessment and diagnosis of KCD diseases, especially those frequently treated at primary healthcare institutes. We confirmed the generation gap in the subgroup analysis according to the license acquisition period, and the ≤5-year group emphasized clinical practice and the KCD, while the >5-year group stressed traditional KM theory and clinical practice guidelines. These findings could be used to develop the NLE-KMD by setting the direction of Korean medicine education and guiding further research from other perspectives

High-Efficiency Skutterudite Modules at a Low Temperature Gradient

Thermoelectric skutterudite materials have been widely investigated for their potential application in mid-temperature waste heat recovery that has not been efficiently utilized A large amount of research has focused on developing materials with a high thermoelectric figure of merit (zT). However, the translation of material properties to device performance has limited success. Here, we demonstrate single-filling n-type Yb0.25Fe0.25Co3.75Sb12 and multi-filling La0.7Ti0.1Ga0.1Fe2.7Co1.3Sb12 skutterudites with a maximum zT of ~1.3 at 740 K and ~0.97 at 760 K. The peak zT of skutterudites usually occurs above 800 K, but, as shown here, the shift in peak zT to lower temperatures is beneficial for enhancing conversion efficiency at a lower hot-side temperature. In this work, we have demonstrated that the Fe-substitution significantly reduces the thermal conductivity of n-type skutterudite, closer to p-type skutterudite thermal conductivity, resulting in a module that is more compatible to operate at elevated temperatures. A uni-couple skutterudite module was fabricated using a molybdenum electrode and Ga&ndash;Sn liquid metal as the thermal interface material. A conversion efficiency of 7.27% at a low temperature gradient of 366 K was achieved, which is among the highest efficiencies reported in the literature at this temperature gradient. These results highlight that peak zT shift and optimized module design can improve conversion efficiency of thermoelectric modules at a low temperature gradient

Association of dietary patterns with the fecal microbiota in Korean adolescents

BACKGROUND: The gut microbiota has emerged as an important environmental factor associated with obesity, type 2 diabetes, and cardiovascular disease, through its interactions with dietary factors. Therefore, we analyzed the composition of the fecal microbiota and levels of biochemical markers related to metabolic disease according to dietary pattern in Korean adolescents. METHODS: We collected fecal samples from 112 student subjects aged 13–16 years with sufficient information available regarding clinical biomarkers and diet, and performed 16S rRNA targeted gene sequencing. RESULTS: Regarding bacterial composition according to taxonomic rank, we found that traditional dietary patterns enriched in plant-based and fermented foods were associated with higher proportions of Bacteroides (Bacteroidaceae) and Bifidobacterium (Bifidobacteriaceae-Actinobacteria) and a lower proportion of Prevotella (Prevotellaceae) relative to modified Western dietary patterns (a greater proportion of animal-based foods). Specifically, the proportion of Bacteroides (Bacteroidaceae) was associated with intake of plant-based nutrients such as fiber; however, that of Prevotella (Prevotellaceae) was negatively associated with these factors. Additionally, we observed that the increase of prevotella (Prevotellaceae) and decrease of Bacteroides (Bacteroidaceae) and Ruminococcaceae had a higher risk of obesity. We also found that the traditional dietary pattern was negatively associated with general and central adiposity and levels of clinical biomarkers, including AST, ALT, total cholesterol, triglyceride, hs-CRP, insulin, and HOMA-IR, whereas the positive associations were found for a modified Western dietary pattern. CONCLUSIONS: These findings suggest that the gut microbiota composition differs markedly according to dietary intake and suggest a role for diet in promoting a gut microbiome associated with the pathogenesis of metabolic disease

Quantitative Analysis of Biogenic Amines in Different Cheese Varieties Obtained from the Korean Domestic and Retail Markets

To evaluate the safety and risk assessment of cheese consumption in the Republic of Korea, sixty cheese samples purchased from the farmstead and retails markets (imported) were analyzed for their biogenic amine (BA) contents. The BA profiles and quantities of eight amines (tryptamine, 2-phenylethylamine, putrescine, cadaverine, histamine, tyramine, spermidine, and spermine) were determined using high-performance liquid chromatography (HPLC). Spermine was the only amine detectable in all the samples. The BAs of fresh cheeses from both farmstead and retail markets were mostly undetectable, and comparatively at lower levels (&lt;125 mg/kg) than ripened samples. Putrescine was undetectable in all the domestic ripened cheeses. The sum of BA levels in the imported ripened cheeses of Pecorino Romano (1889.75 mg/kg) and Grana Padano (1237.80 mg/kg) exceeds &gt;1000 mg/kg, of which histamine accounts nearly 86 and 77% of the total levels, respectively. The tolerable limits of the potential toxic amines, histamine and tyramine surpassed in four and three imported ripened samples, respectively. Furthermore, the presence of potentiators (putrescine and cadaverine) together in samples even with a lower level of toxic amines alarms the risk in consumption. Therefore, adoption of strict hygienic practices during the entire chain of cheese production, along with obligatory monitoring and regulation of BA in cheeses seems to be mandatory to ensure the safety of the consumers

The Influence of Dietary Patterns on the Nutritional Profile in a Korean Child Cohort Study

AbstractObjectivesThe aim of the present study was to identify the major dietary patterns of seven- and eight-year-old Korean children and to examine the relationship between dietary patterns and obesity, nutrient intake, and diet quality.MethodsThe subjects were 284 seven- and eight-year-old children who participated in the Gwacheon child cohort study. Three dietary patterns emerged from the factor analysis: Korean, modified Western, and Western. Cluster analysis was used to classify the subjects into two dietary groups: Korean and Western diet patterns.ResultsThe two different dietary patterns were closely related to dietary quality which in turn was related to health risks. The Western diet group had a lower fiber intake, a higher intake of energy, fat and calcium and a higher dietary diversity score (DDS) than the Korean diet group. The number of days when fruit, milk and dairy products were omitted from the diet was higher for the Korean diet group than for the Western group.ConclusionsDietary patterns and related diet quality should be considered when designing nutrition policy and intervention programs for children