• Bulletin of the Korean Chemical Society
• /
• v.10 no.3
• /
• pp.234-238
• /
• 1989

The crystal structure of partially $Ag^+$-exchanged zeolite A, $Ag_{3.2}Na_{8.8}$-A, vacuum dehydrated at $360^{\circ}C$ and then exposed to 0.1 torr of cesium vapor for 12 hours at $250^{\circ}C$ has been determined by single-crystal X-ray diffraction techniques in the cubic space group Pm3m (a = 12.262(2)${\AA})\;at\;21(1)^{\circ}C$. The structure was refined to the final error indexes $R_1=0.068\;and\;R_2=0.072$ by using 338 reflections for which $I_o\;>\;3{\sigma}(I_o)$ and the composition of unit cell is $Ag_{3.2}Cs_{8.8}-A.\;3\;Cs^+$ ions lie on the centers of the 8-rings at sites of D4h symmetry. Two crystallographycally different 6-ring $Cs^+$ ions were found: 1.5 $Cs^+$ ions at Cs(2) are located inside of sodalite cavity and 4.3 $Cs^+$ ions at Cs(3) are located in the large cavity. The fractional occupancies observed at Cs(2) and Cs(3) indicate that the existence of at least three types of unit cells with regard to the 6-ring $Cs^+$ ions. For example, 50% of unit cells may have two $Cs^+$ ions at Cs(2) and 4 $Cs^+$ ions at Cs(3). 30% of unit cells may have one Cs+ ion at Cs(2) and 5 $Cs^+$ ions at Cs(3). The remaining 20% would have one $Cs^+$ ion at Cs(2) and 4 $Cs^+$ ions at Cs(3). On threefold axes of the unit cell two non-equivalent Ag atom positions are found in the large cavity, each containing 0.64 and 1.92 Ag atoms, respectively. A crystallographic analysis may be interpreted to indicate that 0.64 $(Ag_5)^+$ clusters are present in each large cavity. This cluster may be viewed as a tetrasilver molecule $(Ag_4)^0$(bond length, 2.84${\AA}$) stabilized by the coordination of one $Ag^+$ ion.

• Membrane Journal
• /
• v.31 no.3
• /
• pp.184-199
• /
• 2021

As a branch of covalent organic frameworks (COF), covalent triazine frameworks (CTF) are inherently porous structures composed of networks of repeating hexagonal triazine rings fabricated via the ionothermal trimerization reaction. They also contain plenty of nitrogen functional groups that increase affinity for some chemicals while rejecting others. Because of their tunable properties, many researchers have synthesized and tested CTFs for gas and liquid separation processes. Various studies of novel CTFs, mixed CTF composites, and CTF membranes have experimented for gas adsorption/separation (e.g., CO₂, C₂H₂, H₂, etc.) and desalination. Some CTF studies have determined the limits and potentials through advanced computer simulations while subsequent experiments have tested CTFs for photocatalytic properties, suggesting recyclability for greater sustainability. In this review, the covalent triazine framework-based separation membrane is discussed.

• Journal of the Korean Wood Science and Technology
• /
• v.30 no.2
• /
• pp.79-86
• /
• 2002

Anatomical characteristics of Mulpurenamu (Korean ash, Praxmus rhynchopbylla), Deulmaenamu (Manshurican ash, Fraxinus mandsburica) and Sheamulpure (Sieboldiana ash, Fraxinus sieboldiana) grown in Korea were examined by an optical microscopy and an image analysis. Some characteristics such as boundary of annual rings, shape and size of vessel elements, arrangement of axial parenchyma cells in cross section, and cell volumetric composition showed significant differences between the sample species. In radial variation of elements, fiber length and vessel size increased from the pith for about 10 to 15 years and then reached a more or less constant. The results of this study can be used for identification of wood and indices of wood quality in Fraxinus spp.

• Microbiology and Biotechnology Letters
• /
• v.49 no.2
• /
• pp.174-180
• /
• 2021

Chalcones exhibit multiple biological activities. Various studies have attempted to modify the structure of chalcones with a special focus on the addition of substituents to the benzene rings. However, these chemical modifications did not improve the water solubility and bioavailability of chalcones. Glycosylation can markedly affect the physical and chemical properties of hydrophobic compounds. Here, we evaluated the ability of a highly promiscuous glycosyltransferase (GT) BsGT1 from Bacillus subtilis ATCC 6633 to biosynthesize chalcone glucosides. Purified BsGT1 catalyzed the conversion of 4'-hydroxychalcone (compound 1), 4'-hydroxy-4-methylchalcone (compound 2), and 4-hydroxy-4'-methoxychalcone (compound 3), into chalcone 4'-O-β-D-glucoside (compound 1a), 4-methylchalcone 4'-O-β-D-glucoside (compound 2a), and 4'-methoxychalcone 4-O-β-D-glucoside (compound 3a), respectively. To avoid the addition of expensive uridine diphosphate glucose (UDP-Glc), a whole-cell biotransformation system was employed to provide a natural intracellular environment for in situ co-factor regeneration. The yields of compounds 1a, 2a, and 3a were as high as 90.38%, 100% and 74.79%, respectively. The successful co-expression of BsGT1 with phosphoglucomutase (PGM) and UDP-Glc pyrophosphorylase (GalU), which are involved in the biosynthetic pathway of UDP-Glc, further improved the conversion rates of chalcones (the yields of compounds 1a and 3a increased by approximately 10%). In conclusion, we demonstrated an effective whole-cell biocatalytic system for the enzymatic biosynthesis of chalcone β-D-glucoside derivatives.

• The Korean Journal of Physiology and Pharmacology
• /
• v.26 no.4
• /
• pp.255-262
• /
• 2022

Oxytocin is a neuropeptide produced primarily in the hypothalamus and plays an important role in the regulation of mammalian birth and lactation. It has been shown that oxytocin has important cardiovascular protective effects. Here we investigated the effects of oxytocin on vascular reactivity and underlying the mechanisms in human umbilical vein endothelial cells (HUVECs) in vitro and in rat aorta ex vivo. Oxytocin increased phospho-eNOS (Ser 1177) and phospho-Akt (Ser 473) expression in HUVECs in vitro and the aorta of rat ex vivo. Wortmannin, a specific inhibitor of phosphatidylinositol 3-kinase (PI3K), inhibited oxytocin-induced Akt and eNOS phosphorylation. In the rat aortic rings, oxytocin induced a biphasic vascular reactivity: oxytocin at low dose (10^-9-10^-8 M) initiated a vasorelaxation followed by a vasoconstriction at high dose (10^-7 M). L-NAME (a nitric oxide synthase inhibitor), endothelium removal or wortmannin abolished oxytocin-induced vasorelaxation, and slightly enhanced oxytocin-induced vasoconstriction. Atosiban, an oxytocin/vasopressin 1a receptor inhibitor, totally blocked oxytocin-induced relaxation and vasoconstriction. PD98059 (ERK1/2 inhibitor) partially inhibited oxytocin-induced vasoconstriction. Oxytocin also increased aortic phospho-ERK1/2 expression, which was reduced by either atosiban or PD98059, suggesting that oxytocin-induced vasoconstriction was partially mediated by oxytocin/V1aR activation of ERK1/2. The present study demonstrates that oxytocin can activate different signaling pathways to cause vasorelaxation or vasoconstriction. Oxytocin stimulation of PI3K/eNOS-derived nitric oxide may participate in maintenance of cardiovascular homeostasis, and different vascular reactivities to low or high dose of oxytocin suggest that oxytocin may have different regulatory effects on vascular tone under physiological or pathophysiological conditions.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.23 no.1
• /
• pp.177-182
• /
• 2023

The Act on the Promotion of Mobility for the Transportation Vulnerable stipulates that the transportation vulnerable should be able to enjoy convenience when using public transportation. However, this law is not being implemented properly enough to bring up a petition saying, "Please allow the visually impaired to take a bus." Even if you try to use a call taxi for the disabled instead of public transportation, you have to apply and wait two to three hours. Therefore, this paper aims to design and implement systems for the vulnerable and their guardians, such as increasing the opening time of the ticket gate more than usual if the cane rings a notification on the bus and subway station designated using Bluetooth. Accordingly, it is expected to bring about effects such as the availability of public transportation, economic savings, safety guarantees, and prevention of missing children for the vulnerable.

• The Korea Journal of Herbology
• /
• v.33 no.5
• /
• pp.19-37
• /
• 2018

Objectives : Oryeong-san was composed of Alismatis Rhizoma, Atractylodis Rhizoma Alba, Poria Sclerotium, Polyporus, Cinnamomi Cortex, and known to have hundreds of chemical compounds. The aim of this study was to screen chemical compounds constituting Oryeong-san with the drug-likeness and oral bioavailability from the analysis of their physicochemical properties. Methods : A list of chemical compounds of Oryeong-san was obtained from TM-MC(database of medicinal materials and chemical compounds in Northeast Asian traditional medicine). To remove redundant compounds, the SMILES (Simplified Molecular Input Line Entry System) strings of each compound were identified. All of the physicochemical properties for the compounds were calculated using the DruLiTo(Drug Likeness Tool). Drug-likeness was estimated by QED(Quantitative Estimate of Druglikeness) and OB(Oral bioavailability) was checked based on the Veber's rules. Results : A total of 475 compounds were obtained by eliminating duplication among 544 compounds of 5 medicinal materials. Analysis of the physicochemical properties revealed that the most common values were MW(molecular weight) 200~300 g/mol, ALOGP(octanol-water partition coefficient) 1~2, HBA(number of hydrogen bond acceptors) 0~1, HBD(number of hydrogen bond donors) 0, PSA(polar surface area) 0~50 angstrom, ROTB(number of rotatable bonds) 1, AROM(number of aromatic rings) 0, and ALERT(number of structural alerts) 1. QED had 93% of the values between 0.2 and 0.7, and OB had 90% of the value of TRUE. Conclusions : We in this paper screened the candidate active compounds of Oryeong-san using the QED and Veber's rules. In the future, we will use the screening results to analyze the mechanism of Oryeong-san based on systems pharmacology.

• Journal of the Korean Mathematical Society
• /
• v.59 no.3
• /
• pp.571-594
• /
• 2022

Let D be an integral domain with quotient field K, Pic(D) be the ideal class group of D, and X be an indeterminate. A polynomial overring of D means a subring of K[X] containing D[X]. In this paper, we study almost Dedekind domains which are polynomial overrings of a principal ideal domain D, defined by the intersection of K[X] and rank-one discrete valuation rings with quotient field K(X), and their ideal class groups. Next, let ℤ be the ring of integers, ℚ be the field of rational numbers, and 𝔊f be the set of finitely generated abelian groups (up to isomorphism). As an application, among other things, we show that there exists an overring R of ℤ[X] such that (i) R is a Bezout domain, (ii) R∩ℚ[X] is an almost Dedekind domain, (iii) Pic(R∩ℚ[X]) = $\oplus_{G{\in}G_{f}}$ G, (iv) for each G ∈ 𝔊f, there is a multiplicative subset S of ℤ such that RS ∩ ℚ[X] is a Dedekind domain with Pic(RS ∩ ℚ[X]) = G, and (v) every invertible integral ideal I of R ∩ ℚ[X] can be written uniquely as I = XnQe11···Qekk for some integer n ≥ 0, maximal ideals Qi of R∩ℚ[X], and integers ei ≠ 0. We also completely characterize the almost Dedekind polynomial overrings of ℤ containing Int(ℤ).

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.25 no.12
• /
• pp.1853-1858
• /
• 2021

O-rings fill the gaps between mechanical parts. Until now, the sorting of defective products has been performed visually and manually, so classification errors often occur. Therefore, a camera-based defect classification system without human intervention is required. However, a binarization process is required to separate the required region from the background in the camera input image. In this paper, an adaptive binarization technique that considers the surrounding pixel values is applied to solve the problem that single-threshold binarization is difficult to apply due to factors such as changes in ambient lighting or reflections. In addition, the convex hull technique is also applied to compensate for the missing pixel part. And the learning model to be applied to the separated region applies the residual error-based deep learning neural network model, which is advantageous when the defective characteristic is non-linear. It is suggested that the proposed system through experiments can be applied to the automation of O-ring defect detection.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.58 no.3
• /
• pp.193-198
• /
• 2022

In this study, for the purpose of reducing the catch of small giant octopus in a net pot, an escape experiment of octopus was performed on five types of escape rings of different sizes. As a result of the experiment, the smallest giant octopus with a weight of 406 g was found to escape from an escape ring with a diameter of 30 mm or larger, and 592 g octopus, a weight similar to the octopus of the current minimum landing weight (600 g), escaped from an escape ring with a diameter of larger than 40 mm. An individual weight with 406 g becomes 39 mm when converted from a diameter of 25 mm circular escape vent; that is, the circumference to the inner diameter of the mesh. It can be inferred that the converted mesh size of 39 mm cannot escape. Logistic regression analysis was performed using a generalized linear model (GLM) to investigate the correlation between the ratio of escape ring size/Mantle diameter (R/MD) and the escape rate. As a result, it was found that there was a significant correlation between the R/MD ratio and the escape rate and that the higher the R/MD ratio, the greater the escape rate. As a result of logistic regression analysis, the R/MD value was denoted 0.520 with the 50% escape rate. In addition, it can be estimated to be about 50 mm when converted to the mesh size. Therefore, in this study, the diameter of the escape ring and the size of the escape possible of the octopus were experimentally considered. It was found that there was a significant correlation.