• Bulletin of the Korean Chemical Society
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• v.24 no.2
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• pp.193-196
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• 2003

Nucleophilic addition reactions of benzylamines $(XC_6H_4CH_2NH_2)$ to benzylidene Meldrum's acids (BMA; $YC_6H_4CH=C(COO)_2C(CH_3)_2$) have been investigated in acetonitrile at 20.0 ℃. The rates of addition are greatly enhanced due to the abnormally high acidity of Meldrum's acid. The magnitudes of the Hammett $({\rho}_X\;and\;{\rho}_Y)$ and Bronsted $({\rho}_X$)$ coefficients are rather small suggesting an early transition state. The sign and magnitude of the cross-interaction constant, ${\rho}_{XY}$ (= -0.33), and kinetic isotope effects $(k_H/k_D\;{\stackrel}{~}{=}\;1.5-1.7)$ involving deuterated benzylamine nucleophilies $(XC_6H_4CH_2ND_2)$ are indicative of hydrogen-bonded cyclic transition state. The activation parameters, ${\Delta}H^{\neq}\;{\stackrel}{~}{=}\;4\;kcal\;mol^{-1}\;and\;{\Delta}S^{\neq}\;{\stackrel}{~}{=}\;-37\;e.u.$, are also in line with the proposed mechanism.

• Journal of Gastric Cancer
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• v.24 no.2
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• pp.137-144
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• 2024

Purpose: Laparoscopic proximal gastrectomy (LPG) is a viable choice for treating proximal gastric lesions. However, the occurrence of severe reflux has limited its widespread adoption. To address this issue, the double flap technique (DFT), which incorporates artificial lower esophageal sphincteroplasty, has been developed to prevent reflux problems after proximal gastrectomy. In this study, we aimed to investigate the usefulness of this technique using high-resolution manometry (HRM), impedance pH monitoring, and esophagogastroduodenoscopy (EGD). Materials and Methods: The findings of pre- and postoperative 6-month HRM, pH monitoring, and EGD were compared for 9 patients who underwent LPG with DFT for various proximal gastric lesions at Incheon St. Mary's Hospital from January 2021 to December. Results: A total of 9 patients underwent proximal gastrectomy. Approximately half of the patients had Hill's grade under II preoperatively, whereas all patients had Hill's grades I and II in EGD findings. In the HRM test, there was no significant difference between distal contractile integral (1,412.46±1,168.51 vs. 852.66±495.62 mmHg·cm·s, P=0.087) and integrated relaxation pressure (12.54±8.97 vs. 8.33±11.30 mmHg, P=0.27). The average lower esophageal sphincter (LES) pressure was 29.19±14.51 mmHg preoperatively, which did not differ from 19.97±18.03 mmHg after the surgery (P=0.17). DeMeester score (7.02±6.36 vs. 21.92±36.17, P=0.21) and total acid exposure time (1.49±1.48 vs. 5.61±10.17, P=0.24) were slightly higher, but the differences were not statistically significant. Conclusions: There is no significant functional difference in HRM and impedance pH monitoring tests after DFT. DFT appears to be useful in preserving LES function following proximal gastrectomy.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.9 no.3
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• pp.185-193
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• 1976

The sterol compositions of the Pelecypoda, M. sultataria, S. sachalinensis, and the Gastropoda, H. discus hannai Inc, T. cornutus were investigated. The results areas follows: 1. The contents of the unsaponifiables and sterols of the Pelecypoda, M. sulcataria, S. sathalinensis, and the Gastropoda, H. discus hannai Ino, T. cornutus, are $12.0\%,\;11.8\%,\;and\;16.2\%,\;15.3\%$, respectively. 2. The complex sterols from the Pelecypoda and Gastropoda are well separated on Silica Gel HF 254 TLC impregnated with $15\%$ silver nitrate. 3. The prominent sterols of the Pelecypoda, M. sulcateria and S. sachalinensis, are 22-trans-24-norcholesta-5, $22-dien-3\beta-ol$ $3.0\%\;3.9\%$ 22-dehydrocholesterol $6.7\%,\;10.2\%$, cholesterol $39.0\%,\;48.6\%$ brassicasterol $14.1\%,\;13.8\%$ 24-methylenecholesterol $19.4\%,\;11.5\%$, stigmasterol $2.4\%,\;0\%$ $\beta-sitosterol\;10.5\%,\;11.9\%$, and fucosterol $4.3\%,\;0\%$. 4. Abalone, H. discus hannai Ino, and T. cornutus contain cholesterol $98.0\%,=97.5\% as main component with small amounts of 22-dehydrocholesterol, brassicasterol and desmosterol. In H. discus hannai rno, 24-methylenecholesterot and fucosterol are also found.

• Bulletin of the Korean Chemical Society
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• v.9 no.2
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• pp.98-101
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• 1988

A pure columnar cholesterogen based on the octasubstituted phthalocyanine $(PcH_2)$, S-(+)-2, 3, 9, 10, 16, 17, 23, 24-octakis[5-(dodecyloxy)-2-oxa-pentyl]-phthalocy anine(1a), is described. To evaluate a cholesteric character of 1a, the corresponding achiral $PcH_2$ 1b and the copper complex of chiral $PcH_2$ 1a (CuPc), S-(+)-2,3,9,10,16,17,23,24-octakis[4-(dodecyloxy)- 2-oxapentyl]-phthalocyanine(2a) were also prepared. The chiral 1a exhibited a typical cholesteric texture change in which the transition of platelet (blue phase) to fan-shape texture was observed (K－M－I), whereas the corresponding achiral 1b showed only a focal conic texture (K－ M－I). This is the first instance of a pure columnar cholesterogen observed with discotic liquid crystal systems.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.8
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• pp.616-621
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• 2011

In this paper, CdS thin films, which were widely used window layer of the CdTe and the Cu(In,Ga)$Se_2$ thin film solar cell, were grown by chemical bath deposition, and effects of pH of reaction solution on the structural and optical properties were investigated. For pH<10.5, as the pH of reaction solution was higher, the deposition rate of CdS films was increased by improving ion-by-ion reaction in the substrate surface and the crystallinity of the films was improved. However, when the pH was higher than 10.5, the deposition rate was decreased because of smaller $Cd^{2+}$ ion concentration in the reaction solution. Also, the crystallinity of the films were deteriorated. The CdS films deposited at lower pH showed poor optical transmittance due to adsorbed colloidal particles, while the transmittance was improved for higher pH.

• Computational Structural Engineering
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• v.24 no.1
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• pp.22-25
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• 2011

• Journal of Korean Society for Atmospheric Environment
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• v.13 no.5
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• pp.397-410
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• 1997

An annular denuder filter pack sampling system (ADS) was used to collect acidic air pollutants in Pusan. During the study period (from June 1995 to November 1995), forty eight samples were collected every 12 hours starting from 6:00 in the morning. These samples were devided into two sets of data for day (6:00 a.m.-6:00 p.m.) and night (6:00 p.m.-6:00 a.m.). The chemical species were analyzed for HN $O_3$, HN $O_2$, S $O_2$ and N $H_3$ in the gas Phase, and N $O_3$$^{[-10]}$ , S $O_4$$^{2-}$ and N $H_4$$^{+}$ in the particulate phase. The mean concentrations measured from this study were 0.24, 1.91, 30.07 and 4.24 $\mu\textrm{g}$/㎥ for HN $O_3$, HN $O_2$, S $O_2$ and N $H_3$, respectively. The mean concentrations of N $O_3$$^{[-10]}$ , S $O_4$$^{2-}$ and N $H_4$$^+{\ulcorner}$ were 1.95, 7.36 and 3.48 $\mu\textrm{g}$/㎥, respectively. The mean concentrations of gaseous species except for HN $O_2$ were higher in daytime than in nighttime, but the reverse was true in the particulates except for N $H_4$$^{+}$. +/..

• Archives of Pharmacal Research
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• v.29 no.2
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• pp.172-177
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• 2006

Hepatotoxic potential of 2, 3-dibromopropene (2, 3-DBPE) and its conjugation with glutathione (GSH) were investigated in male ICR mice. Treatment of mice with 20, 50, and 100 mg/kg of 2, 3-DBPE for 24 h caused elevation of serum alanine aminotransferase and aspartate aminotransferase activities. The hepatic content of GSH was not changed by 2, 3-DBPE. Meanwhile, the GSH content was slightly reduced when mice were treated with 2, 3-DBPE for 6 h and significantly increased 12 h after the treatment. Subsequently, a possible formation of GSH conjugate of 2, 3-DBPE was investigated in vivo. After the animals were treated orally with 20, 50, and 100 mg/kg of 2, 3-DBPE, the animals were subjected to necropsy 6, 12, and 24 h later. A conjugate of S-2-bromopropenyl GSH was identified in liver and serum treated with 100 mg/kg of 2, 3-DBPE by using liquid chromatography-electrospray ionization tandem mass spectrometry. The protonated molecular ions $[M+H]^+$ of S-2-bromopropenyl GSH were observed at m/z 425.9 and 428.1 in the positive ESI spectrum with a retention time of 6.35 and 6.39 min, respectively. In a time-course study in livers following an oral treatment of mice with 100 mg/kg of 2, 3-DBPE for 6, 12, and 24 h, the 2, 3-DBPE GSH conjugate was detected maximally 6 h after the treatment. The present results suggested that 2, 3-DBPE-induced hepatotoxicity might be related with the production of its GSH conjugate.

• Laser Solutions
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• v.7 no.3
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• pp.47-50
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• 2004

In this research, we investigated the characteristic of $ZnS_{0.24}Se_{0.76}/GaAs$ heterostructure by using photoreflectance sprctroscopy(PR). The oscillations observed above the 1.43 eV range were attributed Franze-Keldysh effect. The interface electric filed of $GaAs/ZnS_{0.24}Se_{0.76}\;is\;2.153{\times}104\;V/cm$.

• The Bulletin of The Korean Astronomical Society
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• v.24 no.2
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• pp.21-22
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• 1999