• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.12
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• pp.1185-1192
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• 2012

The typical operating temperature of an automotive fuel cell is lower than that of an internal combustion engine, which necessitates a refined strategy for thermal management. In particular, the performance of the cooling module has to be higher for a fuel cell system because the temperature difference between the fuel cell and the surrounding is lower than in the case of the internal combustion engine. Even though the cooling system of an automotive fuel cell determines the operating temperature and temperature distribution of the fuel cell, it has attracted little research attention. This study presents the mathematical model of a cooling system for an automotive fuel cell system using Matlab/$Simulink^{(R)}$. In particular, a radiator model is developed for design optimization from the development stage to the operating stage for an automotive fuel cell. The cooling system model comprises a fan, pump, and radiator. The pump and fan model have an empirical relation, and the dynamics of the pump and fan are only explained by motor dynamics. The basic design study was conducted, and the geometric setup of the radiator was investigated. When the control logic was applied, the pump senses the coolant inlet temperature and the fan senses the coolant out temperature. Additionally, the cooling module is integrated with the fuel cell system model so that the performance of the cooling module can be investigated under realistic operating conditions.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.33 no.1
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• pp.20-25
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• 2022

Background and Objectives Globus pharyngeus is one of the most common symptoms of patients visiting otorhinolaryngology out-patient clinic, and usually long-lasting, difficult to treat, and frequently recurrent. Mucomyst^®, N-acetyl cysteine is an inhalation agent mainly used for mucolysis and reducing inflammation in airway via antioxidative effect. The purpose of this study was to evaluate the efficacy of inhaled Mucomyst^® treatment in patients with globus pharyngeus refractory to proton pump inhibitor (PPI). Materials and Method We prospectively evaluated the efficacy of Mucomyst^® in relieving symptoms of globus pharyngeus refractory to PPI in nine medical centers. Three hundred and three patients enrolled and finally 229 patients finished the inhaled Mucomyst^® therapy for 8 weeks. We analyzed the change of Reflux Symptom Index (RSI), Reflux Finding Score (RFS), Visual Analogue Scale (VAS) for globus, and Globus Pharyngeus Symptom Scale (GPS) after use of Mucomyst^® for 4 and 8 weeks. Results The GPS, RSI, RFS, and VAS score significantly decreased serially in patients who finished 8 week-inhalation treatment. The GPS improvement gap was significantly correlated with initial GPS (p<0.001) in multiple regression analysis. Conclusion Inhaled Mucomyst^® therapy was effective for the reduction of both subjective and objective findings in refractory globus patients. This study might suggest new treatment option for patients with globus. However, further thorough studies would be needed to assess the real effect of inhaled Mucomyst^® treatment as a standard treatment for globus.

• Korean Journal of Bronchoesophagology
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• v.10 no.2
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• pp.35-42
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• 2004

Background and objective : Rabeprazole is a new generation proton pump inhibitor, which has a rapid onset after first dose, predictable efficacy in all patients regardless of CYP2C19 genotype status, and less nocturnal acid breakthrough. The aim of the study is to investigate clinical efficacy and safety of rabeprazole sodium (Pariet 10mg qd)when administered once daily to patients with laryngopharyngeal reflux(LPR) disease. Methods : Among the patients who had visited the Department of Otolaryngology, those with LPR symptoms, had undergone laryngoscopy. Symptoms and endoscopic laryngeal sings were recorded initially, at 1 month, 2 months, 3 months, and more than 3 months, All patients were evaluated for clinical efficacy on the basis of symptom scores, reflux finding score(RFS), and side effects. Results : In general, most symptom scores and RFS improved over the time. Efficacy of the Pariet on LPR-related symptoms were $63.2\%,\;77.5\%,\;78.7\%,\;and\;90.9\%$ before 4 weeks, 4 to 8 weeks, 8 to 12 weeks, and after 12 weeks respectively. Efficacy on the RFS were $61.8\%,\;78.4\%,\;82.9\%,\;and\;85.5\%$ before 4 weeks, 4 to 8 weeks, 8 to 12 weeks, and after 12 weeks respectively. Pariet was well tolerated and was associated with few drug-related side effects. Conclusion Because of its efficacy and safety, Pariet may prove to be an alternative to currently available proton pump inhibitors.

• The Journal of Internal Korean Medicine
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• v.31 no.1
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• pp.128-141
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• 2010

Purpose : The object of this study was to observe the suppressive effects of Yijintang-gamibang (YJGMB), Yijintang with Atractylodis Rhizoma, Massa Medicata Fermentata, Hordei Fructus Germiniatus, and Coptidis Rhizoma. YJGMB has been traditionally used in Korean medicine for treating various digestive diseases. We tested it on the rat reflux esophagitis (RE) induced by pylorus and forestomach ligation in rats as compared with omeprazole, a well-known proton pump inhibitor. Method : Three different dosages of YJGMB 200, 100 and 50mg/kg, were orally pretreated once a day for 28 days before pylorus and forestomach ligation. Seven groups, each of 8 rats per group were used in the study. Six hours after pylorus and forestomach ligation, changes of the stomach and esophagus lesion areas, gastric volumes, acid and pepsin outputs, invasive lesion percentages, fundic mucosa and total thicknesses were measured as histomorphometry. The results were compared with omeprazole, antioxidant and proton pump inhibitor, and 30 and 10mg/kg treated groups in which the effects on RE were already confirmed. Results : As results of pylorus and forestomach ligation, marked increases of esophageal and gastric mucosa lesion areas, gastric volumes, acid outputs, pepsin outputs were observed with histopathological changes of RE, such as hemorrhages, ulcerative lesions and edematous changes on the fundic mucosa. However, these pylorus and forestomach ligation-induced RE were dose-dependently inhibited by treatment of 200, 100 and 50mg/kg of YJGMB. YJGMB 200mg/kg showed similar protective effects as compared with 30mg/kg of omeprazole in the present study, and more favorable effects were observed in 50mg/kg of YJGMB treated rats as compared with omeprazole 10mg/kg in the present study. Conclusion : The results obtained in this study suggest that YJGMB has favorable protective effects on the RE induced by pylorus and forestomach ligation. Therefore, it is expected that YJGMB will also show favorable effects on RE corresponding well to the suggestion of traditional Korean medicine. However, more detailed mechanism studies should be conducted in future with the screening of the biological active chemical compounds in herbs.

• Archives of Pharmacal Research
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• v.21 no.1
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• pp.6-11
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• 1998

The activities of two types of antiulcer agents against 9 strains of Helicobacter pylori (H. pylori) were determined by the agar dilution method. The antiulcer agents were YJA20379, a newly synthesized proton pump inhibitor developed by Yung-jin Pharmaceutical company, and omeprazole. Both compounds were found to have significant activities against this organism. The MIC values of YJA20379 and omeprazole were 11.7 and $31.25{\mu.g/ml}$ respectively. In addition, the inhibitory potency of both compounds was investigated on H. pylori urease which is believed to be an important colonization and virulence factor in the pathogenesis of gastritis and peptic ulcers. These compounds dose-dependently inhibited urease extracted with distilled water and their $IC_50$ values were $16.4{\times}10^{-5} M and 14.3{\times}10^{-5}M,$ respectively. In addition, a pH-dependent study to determine whether inhibitory potency would be activated by acid condition was performed. It was found that unlike omeprazole, YJA20379 was not affected by acid condition. To determine the inhibition pattern and optimal concentration of substrate, kinetics were evaluated at various pH levels (pH 5.0, 7.0, and 8.5). The data show that YJA20379 noncompetitively inhibited H. pylori urease and $K_M/K_i$values were 0.96 $mM/60{\mu}M (pH 5.0), 0.56 mM/141.5 {\mu}M (pH 7.0)$, and $1.94mM/34{\mu}M (pH 8.5)$, respectively. Based on data obtained, it is concluded that YJA20379 is a significant inhibitor of H. pylori growth and urease and therefore, taking these results into consideration, YJA20379 might be a beneficial therapy for gastritis and peptic ulcers induced by H. pylori.

• The Korean Journal of Physiology
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• v.30 no.2
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• pp.197-208
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• 1996

Endosomes lower their internal pH by an ATP-driven proton pump, which is critical to dissociation of many receptor-ligand complexes, the first step in the intracellular sorting of internalized receptors and ligands. Endosomes are known to exhibit n great range of pH values that can vary between 5.0 and 7.0 within a single cell although the factors that regulate endosomal pH remain uncertain. To evaluate the morphological and topological differences of endosomes in the different stages, confocal microscopy was used. The early endosomes labeled with fluorescein isothiocyanate-dextran for 10 min at $37^{\circ}C$ were identifiable at the peripheral and tubule-vesicular endosome compartment. In contrast, the late endosomes formed by 10 min pulse and 20 min trace were located deeper in the cytoplasm and showed more vesicular features than early endosomes. For the purpose of determining whether ATP-dependent acidification was heterogeneous and whether the differences in acidification were attributed to differences in the activity of $Na^{+}-K^{+}$-ATPase and/or $Cl^{-}$ channel, endocytic compartments were fractionated into subpopulation using percoll gradient and measured ATP-dependent acidification. While all fractions exhibited ATP-dependent acidification activity, both the initial rate of acidification and extent of proton translocation were lower in early endosomes and gradually increased in late endosomes. Phosphorylation by PKA and ATP enhanced ATP-dependent acidification in both early and late endosomes, hut there was no difference in the degree of enhancement by phosphorylation between two subpopulations. When ATP-dependent acidification was determined in the presence or absence of vanadate ($Na_{3}VO_{4}$) or ouabain, only early endosomes exhibited the vanadate or ouabain dependent stimulation of acidification activity, suggesting the inhibition of $Na^{+}-K^{+}$-ATPase. Therefore, it seems probable that the inhibition of early endosome acidification by $Na^{+}-K^{+}$-ATPase observed in vitro at least in part plays a physiological role in controlling the acidification of early endosomes in vivo.

• Journal of Microbiology and Biotechnology
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• v.6 no.6
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• pp.391-396
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• 1996

The Gram-negative marine bacterium Marinomonas vaga, which requires 0.5 M NaCl concentration for optimal growth, is slightly halophilic. The growth of M vaga was highly resistant to the proton conductor, carbonyl cyanide m-chlorophenylhydrazone (CCCP) under alkaline pH conditions (pH 8.5) but very sensitive to CCCP under acidic pH conditions (pH 6.5). These results suggest that the respiratory chain-linked NADH oxidase system of M. vaga may lead to generation of a $Na^{+}$ electrochemical gradient. In order to examine the existence of $Na^{+}$-stimulated NADH oxidase in M. vaga, membrane fractions were prepared by the osmotic lysis method. The membrane-bound NADH oxidase oxidized both NADH and deamino-NADH as substrates and required $Na^{+}$ for maximum activity. The maximum activity of NADH oxidase was obtained at about pH 8.5 in the presence of 0.2 M NaCl. The site of $Na^{+}$-dependent activation in the NADH oxidase system was at the NADH:quinone oxidoreductase segment. The NADH oxidase and NADH:quinone oxidoreductase were very sensitive to the respiratory chain inhibitor, 2-heptyl-4-hydroxyquinoline-N-oxide (HQNO) in the presence of 0.2 M NaCl but highly resistant to another respiratory inhibitor, rotenone. Based on these findings, we conclude that M. vaga possesses the $Na^{+}$-dependent NADH:quinone oxidoreductase that may function as an electrogenic $Na^{+}$ pump.

• Journal of Gastric Cancer
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• v.20 no.3
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• pp.337-343
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• 2020

Distal gastrectomy with Billroth I or II reconstruction may cause duodenogastroesophageal reflux (DGER), thereby resulting in digestive or respiratory symptoms. The mainstay of treatment is medication with proton pump inhibitors. However, these drugs may have limited effects in DGER. Laparoscopic fundoplication has been proven to be highly effective in treating gastroesophageal reflux disease (GERD), but it cannot be performed optimally for GERD that develops after gastrectomy. We report the case of a 72-year-old man with a history of distal gastrectomy and Billroth I anastomosis due to early gastric cancer. GERD due to bile reflux occurred after surgery and was refractory to medical therapy. The patient underwent Roux-en-Y conversion from Billroth I gastroduodenostomy and hiatal hernia repair with only cruroplasty. Fundoplication was not performed. His symptoms improved significantly after the surgery. Therefore, laparoscopic hiatal hernia repair and Roux-en-Y conversion can be an effective surgical procedure to treat medically refractory DGER after Billroth I gastrectomy.

• Korean Journal of Clinical Pharmacy
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• v.7 no.1
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• pp.22-32
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• 1997

The gastrointestinal disorders (GI disorders) is one of the most common diseases in Korea. The community pharmacists are often faced with the complaints of symptoms due to the GI disorders. However the drugs used to treat the GI disorders are frequently abused by the patients themselves because these drugs are easily available and have high placebo effects. Therefore, we have reviewed the digestive diseases statistics of 1996 to find out the frequencies of the GI disorders in the outpatients of Samsung Medical Center. Using these statistic data, we figured out the frequently diagnosed GI disorders and analysed commonly used prescriptions from February 1st to 28th of 1997. In addition, we also evaluated the commonly used drugs in these prescriptions. About twenty thousands of patients visited the hopital because of their GI symptoms in 1996. It was found that dyspepsia, viral hepatitis, and gastric and duodenal ulcer disease are frequently diagnosed in these patients. In a point of view on other GI disorders, gastritis and duodenitis, irritable bowel syndrome, gastroesophageal reflux disease, constipation and diarrhea were commonly detected. And a number of drugs were prescribed to treat the GI disorders, which included the prokinetics, Histamine-2 receptor antagonists, proton pump inhibitor, antacids, tranquillizers, antidepressants, antispasmodics, laxatives and so on. Interestingly, there were many prescriptions composing of the antibiotic regimens to eradicate H. pylori which has been proven to cause peptic ulcers.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.11 no.1
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• pp.70-74
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• 2008

Herpes simplex virus has rarely been identified as a cause of esophagitis in immunocompetent children. This virus affects predominantly males presenting with symptoms of fever, odynophagia, dysphagia, and retrosternal pain of acute onset. Esophagoscopy typically reveals exudative well-circumscribed ulcerations of the distal and/or mid-esophagus. Further investigations using biopsy, viral culture, polymerase chain reaction (PCR), and seroconversion of antibodies to Herpes simplex are recommended to assist with a definitive diagnosis. This esophagitis is often a self-limited infection in immunocompetent children. Nevertheless, antiviral treatment may expedite symptom relief with Herpes simplex virus infection. It is imperative to document herpes esophagitis in cases with subsequent severe odynophagia in immunocompetent children. Here we present the case of a 12-year-old immunocompetent boy with herpes esophagitis.