Metabolite profiling of Cheonggukjang, a fermented soybean paste,during fermentation by gas chromatography-mass spectrometry and principal component analysis

Metabolite profiling by applying principal component analysis (PCA) to a GC–MS data set was performed to assess changes in a select number of pre-defined metabolites during the fermentation of Cheonggukjang. A total of 20 amino acids, 12 organic acids, and nine fatty acids were found as targeted metabolites in Cheonggukjang. As fermentation proceeded, the levels of most amino acids decreased during the early stage of fermentation, but increased in the later part of fermentation. On the other hand, amounts of fatty acids increased throughout the fermentation process, while those of most organic acids, except for tartaric acid, decreased. A PCA score plot illustrated good separation of the Cheonggukjang samples according to fermentation period by combining principal component 1 (PC 1) (36.8%) with PC 2 (30.3%). Tryptophan, citric acid, β-alanine, itaconic acid, 2-hydroxyglutaric acid, γ-aminobutyric acid, leucine, malic acid, and tartaric acid were the major components that differentiated the various samples.     

A GSM/EGSM/DCS/PCS direct conversion receiver with integrated synthesizer

A global system for mobile communications direct conversion receiver with an integrated synthesizer is implemented with a 0.35-mum BiCMOS technology. Proposed second-order intercept point calibration method is analyzed and verified by measurements. The maximum IIP2=66 dBm is achieved by an 8-b resistive calibration code. The receiver draws 57/63 mA from a 2.7-V supply     

A comparative study on stub columns with various steel grades subjected to concentric axial loading

In this study, various structural steels were evaluated to determine whether they satisfy the standards for compression members. Also, stub columns subjected to concentric axial loads were tested to check the applicability of the current design criteria to SM570TMC steel. The variables in the test were the plate-edge restraint and the width-to-thickness ratio. Specimens included 5 box-section and 10 H-section specimens, and were designed to meet the noncompact section. Coupon test results showed that yield strength and tensile strength were the higher than nominal strength, and one specimen was reclassified as a slender section. All specimens except the one specimen reclassified as a slender section satisfied with the strength demanded by the design criteria. The strength reduction factor curve of the investigated specimens showed that most of the specimens satisfied the current design criteria, but some specimens did not reach the required strength because of the uncertainty of material.     

Response of fetal rat calvarial cells to nanotubular titanium oxide surface

This study examined the cell response to a TiO2 nanotubular surface (Ti-NT) for future biomedical applications. The level of cell attachment and spreading at 20 min and 60 min was evaluated by SEM. IL-6 and PGE2 secretion was evaluated by ELISA. In SEM analysis, the Ti-NT surface had more fully spread cells compared to the machined titanium surface (Ti-S). ELISA revealed that the level of IL-6 and PGE2 production was higher on the Ti-NT than on the Ti-S. These results suggest that a surface treatment with a nanotubular TiO2 surface enhances the early osteoblast responses, such as cell spreading and cytokine release, which are important for subsequent cell functions and bone healing in vivo.     

Physicochemical properties of Korean rice wine (Makgeolli) fermented using yeasts isolated from Korean traditional nuruk,a starter culture

The applicability of Saccharomycopsis fibuligera CJN1020, Pichia jadinii CJN1287, and Saccharomyces cerevisiae CJN1514 isolated from Korean nuruk, a starter culture, for preparation makgeolli was investigated. These yeasts were suitable for preparation of both white rice makgeolli using a steam method and white rice-brown rice-wheat flour (WBW) makgeolli using a complex method. Upon physicochemical evaluation, there were no differences in the final ethanol concentrations between white rice makgeolli and WBW makgeolli. Differences in final ethanol yields occurred according to yeast species. Final ethanol yields using S. fibuligera and P. jadinii were 16 and 18% using S. cerevisiae. WBW makgeolli samples received higher sensory scores than white rice makgeolli for overall preference. GC/MS analysis revealed higher amounts of aromatic compounds in WBW makgeolli than in white rice makgeolli. The complex method was suitable for preparation of makgeolli using brown rice and wheat flour.     

Experiment and analysis of circular hollow section gap K-joints with grade HSB 600 steel

Circular hollow steel sections are examples of members that are becoming increasingly popular. The demand of high strength with sufficient ductility for materials is increasing for design of long-span and high-rise structures. HSB 600 steel, High performance Steel for Bridge with minimum tensile yield strength, f _y , of 480 N/mm² for all thickness, was introduced in the Korea Building Code (KBC 2009, 2009). However, current design standards may not be applicable to circular hollow sections with HSB 600 steel since they have been established based on tests of steels with yield stress up to 355 MPa and a ductility ratio up to 0.8. Six full scale circular hollow section gap K-joints were tested and analyzed to investigate the applicability of current design standards. Two series using SHB600 and SS400 steel grades were tested. Three specimens in each series with various gaps between bracing members were evaluated. All chord members were 2,250 mm and brace members were 1,400 mm in length. All chord and brace members were 350mm in diameter and 12 mm in wall thickness. Based on the limited test and analysis results of this circular hollow section gap K-joint, the applicability to current standards, the possible elastic local buckling and gap effects of the different grades of steel are examined.     

Fabrication of nano- and micro-scale UV imprint stamp using diamond-like carbon coating technology

Two-dimensional (2-D) and three-dimensional (3-D) diamond-like carbon (DLC) stamps for ultraviolet nanoimprint lithography were fabricated with two methods: namely, a DLC coating process, followed by focused ion beam lithography; and two-photon polymerization patterning, followed by nanoscale-thick DLC coating. We used focused ion beam lithography to fabricate 70 nm deep lines with a width of 100 nm, as well as 70 nm deep lines with a width of 150 nm, on 100 nm thick DLC layers coated on quartz substrates. We also used two-photon polymerization patterning and a DLC coating process to successfully fabricate 200 nm wide lines, as well as 3-D rings with a diameter of 1.35 microm and a height of 1.97 microm, and a 3-D cone with a bottom diameter of 2.88 microm and a height of 1.97 microm. The wafers were successfully printed on an UV-NIL using the DLC stamps without an anti-adhesive layer. The correlation between the dimensions of the stamp's features and the corresponding imprinted features was excellent.     

Topoisomerase IIIβ Deficiency Induces Neuro-Behavioral Changes and Brain Connectivity Alterations in Mice

Topoisomerase IIIβ (Top3β), the only dual-activity topoisomerase in mammals that can change topology of both DNA and RNA, is known to be associated with neurodevelopment and mental dysfunction in humans. However, there is no report showing clear associations of Top3β with neuropsychiatric phenotypes in mice. Here, we investigated the effect of Top3β on neuro-behavior using newly generated Top3β deficient (Top3β^−/−) mice. We found that Top3β^−/− mice showed decreased anxiety and depression-like behaviors. The lack of Top3β was also associated with changes in circadian rhythm. In addition, a clear expression of Top3β was demonstrated in the central nervous system of mice. Positron emission tomography/computed tomography (PET/CT) analysis revealed significantly altered connectivity between many brain regions in Top3β^−/− mice, including the connectivity between the olfactory bulb and the cerebellum, the connectivity between the amygdala and the olfactory bulb, and the connectivity between the globus pallidus and the optic nerve. These connectivity alterations in brain regions are known to be linked to neurodevelopmental as well as psychiatric and behavioral disorders in humans. Therefore, we conclude that Top3β is essential for normal brain function and behavior in mice and that Top3β could be an interesting target to study neuropsychiatric disorders in humans.     

Aroma Active Compounds of Bulgogi

: Volatile components in bulgogi were extracted by high vacuum sublimation (HVS) and solid phase microextraction (SPME). The extracts were then analyzed by gas chromatography‐olfactometry (GCO) conducted on 2 columns with different polarities. Aroma dilution methods were used with a serial dilution of the extract in HVS‐GCO and varying the GC injector split ratios in SPME‐GCO to determine aroma active compounds of bulgogi. In HVS‐GCO, methional (described as cooked potato/soy sauce) exhibited the highest flavor dilution (FD) factor, followed by 2‐acetyl‐2‐thiazoline (described as nutty/popcorn/peanut), furaneol (described as caramel/sweet), and 2‐ethyl‐3,5‐dimethylpyrazine (described as nutty/coffee/chocolate). In SPME‐GCO, allyl mercaptan (described as garlic/bulgogi) showed the highest FD factor, followed by methional (described as cooked potato/soy sauce), 2‐ethyl‐3,5‐dimethylpyrazine (described as nutty/coffee/chocolate), and 2‐acetylpyrazine (described as nutty/peanut/cooked rice). These sulfur‐containing compounds and heterocyclic compounds, which had high FD factors and characteristic odor notes, could be important to bulgogi flavor.     

Free-radical-scavenging and tyrosinase-inhibition activities of Cheonggukjang samples fermented for various times

Methanol extracts of Cheonggukjang, fermented for various times, were evaluated for their free-radical-scavenging and tyrosinase-inhibitory activities and the underlying mechanisms were elucidated. The free-radical-scavenging activity was highest for Cheonggukjang extracts fermented for 40 h and this decreased as the fermentation time shortened. The tyrosinase-inhibition activity increased with the length of fermentation. While levels of total phenolic compounds were highest in the 40-h-fermented Cheonggukjang samples, the total flavonoid content was lower compared to samples fermented for shorter times. Therefore, the antioxidative and tyrosinase-inhibition activities exhibited by methanol-extracted Cheonggukjang samples may be attributable to the contents of total phenolic compounds.