• Bulletin of the Korean Chemical Society
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• v.32 no.7
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• pp.2301-2305
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• 2011

The potential energy surface (PES) for the loss of HCN or HNC from the pyrazine molecular ion was determined based on quantum chemical calculations using the G3//B3LYP method. Four possible dissociation pathways to form four $C_3H_3N^{+{{\bullet}}$ isomers were examined. A Rice-Ramsperger-Kassel-Marcus quasi-equilibrium theory model calculation was performed to predict the dissociation rate constant and the product branching ratio on the basis of the obtained PES. The resultant rate constant for the HCN loss agreed with the previous experimental result. The kinetic analysis predicted that the formation of $CH=CHN{\equiv}CH^{+{\bullet}}+HCN$ was predominant, which occurred by three consecutive steps, a C-C bond cleavage to form a linear intermediate, a rearrangement to form an H-bridged intermediate, and elimination of HCN.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.25 no.7
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• pp.413-417
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• 2013

The organic Rankine Cycle (ORC) uses a kind of refrigerant as a working fluid that evaporates at relatively low temperature, as the Rankine Cycle uses superheated steam as the working fluid. A small scale ORC test bench was installed, and two different working fluids (R245fa and R134a) were injected into the test bench. The test bench was in operation with the two different working fluids under the same conditions. The effects against the system performance from the different working fluids were analysed, and root causes were identified. Other factors reflecting the power generation efficiency were also found. A conclusion was drawn, that R245fa makes the system perform better, than R134a.

• Bulletin of the Korean Chemical Society
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• v.35 no.10
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• pp.3021-3024
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• 2014

The potential energy surface (PES) for the dissociation of the 2-hydroxypyridine (2-HP) radical cation was determined from G3//B3LYP calculations, including the loss of CO, HCN, and HNC. The formation of the 1H-pyrrole radical cation by decarbonylation through a more stable tautomer, the 2-pyridone (2-PY) radical cation, was the most favorable dissociation pathway. Kinetic analysis by the Rice-Ramsperger-Kassel-Marcus model calculations was carried out based on the obtained PES. It is proposed that the dissociation occurs after a rapid tautomerization to 2-$PY^{{\cdot}+}$, and that most of the ions generated by ionization of 2-HP have the structure of 2-$PY^{{\cdot}+}$ at equilibrium above the tautomerization barrier.

• Radiation Oncology Journal
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• v.38 no.2
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• pp.84-92
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• 2020

Patients undergoing radiation therapy for head and neck cancer (HNC) experience significant early and long-term side effects. The likelihood and severity of complications depends on a number of factors, including the total dose of radiation delivered, over what time it was delivered and what parts of the head and neck received radiation. Late side effects include: permanent loss of saliva; osteoradionecrosis; radiation recall myositis, pharyngoesophageal stenosis; dental caries; oral cavity necrosis; fibrosis; impaired wound healing; skin changes and skin cancer; lymphedema; hypothyroidism, hyperparathyroidism, lightheadedness, dizziness and headaches; secondary cancer; and eye, ear, neurological and neck structures damage. Patients who undergo radiotherapy for nasopharyngeal carcinoma tend to suffer from chronic sinusitis. These side effects present difficult challenges to the patients and their caregivers and require life-long strategies to alleviate their deleterious effect on basic life functions and on the quality of life. This review presents these side effects and their management.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.30 no.1
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• pp.5-8
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• 2019

Aspiration, the entry of material into the airway below the true vocal folds, has been reported in various type of postsurgical head and neck patients. The important of correctly identifying the cause of aspiration in the head and neck surgical patient. Clearly each cause represents a different physiologic or anatomic disorder which requires different management strategy. We discuss about the cause of aspiration during head and neck treatment.

• Korean Journal of Head & Neck Oncology
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• v.27 no.1
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• pp.47-53
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• 2011

Purpose : Concurrent chemoradiotherapy(CCRT) with 3 weekly cisplatin is the standard treatment of locally advanced head and neck cancer(HNC). The aim is to evaluate the efficacy and toxicities of low-dose weekly cisplatin-based CCRT, which was devised to reduce the toxicity of CCRT. Method : We retrospectively analyzed HNC patients who received low-dose weekly cisplatin-based CCRT between 2008 and 2010. Cisplatin 35mg/$m^2$ was weekly given to all patients during radiotherapy. The efficacy was evaluated by the degree of clinical response, treatment failure and survival. The toxicity was evaluated by hematologic toxicities and oral mucositis. Results : A total of 27 patients were analyzed and median age was 59(range 31-81). The ratio of administered dose of radiotherapy and cisplatin to planned dose were 0.98 and 0.93, respectively. Complete remission and partial remission were 73% and 23%, respectively. Treatment failure was observed in 8(30%) patients. 1-year survival rate and 1-year disease free survival rate were 82% and 59%, respectively. Overall survival and progression-free survival did not reach median time. Grade 3/4 anemia, neutropenia, thrombocytopenia and oral mucositis were observed in 11%, 19%, 7% and 32% of patients, respectively. In terms of administered cycles, however, only 1-3% of grade 3/4 hematologic toxicities occurred among total 190 cycles. Severe oral mucositis were statistically associated with old age(p=0.003). Treatment failure had no statistical relation with age, pathology, primary site and stage. Conclusion : Low-dose weekly cisplatin-based CCRT seemed to deliver enough dose of cisplatin and to show low drop-out rate and good efficacy with low hematologic toxicities.

• Clean Technology
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• v.27 no.2
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• pp.124-131
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• 2021

As declarations of carbon neutrality are spreading throughout the world, much research is being conducted on biodegradable polymers. In this study, nanocellulose, which comprises the largest amount of natural polymer currently available in the world, was proposed as a substitute for non-biodegradable polymers. We chose to modify the surface functional group of crystalline nanocellulose using glycidoxypropyl trimethoxysilane (GPTMS), which is a silane coupling agent, and the product was then used to form a film with low density polyethylene (LDPE). We then conducted measurements using a Fourier transform infrared spectrophotometer (FT-IR) in addition to measuring hydrophilic/lipophilicity of the surface functional group modification of crystalline nitrocellulose as well as that of a polymer composite using the hybrid nanocellulose (H-NC). For compatibility with petroleum-based polymers, the best tensile strength and transparency was found when the H-NC was reacted at pH 14 and 1 wt% compared with LDPE. From the test results, we found that it is possible to modify the surface functional groups of nanocellulose using a silane coupling agent. In addition, the high compatibility of nanocellulose with petroleum-based polymers is expected to help in reaching carbon neutrality by reducing the use of fossil fuels.

• Biomolecules & Therapeutics
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• v.12 no.4
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• pp.235-241
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• 2004

Gagam-danguiemja (GDGJ), a traditional Korean prescription, has been used as therapeutics for atopic allergic diseases such as atopic dermatitis. To evaluate the atopic allergic effect of modified GDGJ, we investigated a possible effect of GDGJ on mast cell-mediated allergic reaction, cytokinases secretion and mRNA expression in vivo and in vitro. Mast cells are a potent source of mediators that regulate the inflammatory response in allergic reaction. In mice orally administered by GDGJ (0.01, 0.1 and 1.0 g/kg) for 1 h, compound 48/80-induced ear oedema was significantly reduced. TNF-${\alpha}$, IL-8, and IL-6 secretion were inhibited by GDGJ in the human mast cell line (HNC-1). But TNF-${\alpha}$, IL-8, and IL-6 mRNA expression were not inhibited by GDGJ at the dose of 0.01 mg/ml. These findings may help in understanding the mechanism of action of this herbal medication, leading to the control of mast cells in atopic allergic reaction like AD.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.sup3
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• pp.87-91
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• 2016

To investigate whether excision repair cross complementing-group1 (ERCC1) expression status could serve as a bio-predictor of response to platinum-based induction chemotherapy for head and neck cancers (HNCs) patients with a diagnosis of epithelial HNC were studied retrospectively. Paraffin embedded tumor samples of the patients were analyzed by reverse transcription-polymerase chain reaction (RT-PCR) to determine ERCC1 expression status and its correlation with response to platinum-based induction chemotherapy was investigated. Of 44 included patients, 33 were male (75%) and 11 were female (25%) with a mean age of 53 years. Some 36% of patients whose tumor samples had high ERCC1 expression showed no response to induction chemotherapy. The value for patients with low ERCC1 expression was 9% and the difference was statistically significant (p=0.03). The ERCC1 expression state did not significantly vary between patient groups according to sex, age, primary tumor site, and tumor and node stage. Our study indicates that ERCC1 expression status detected by RT-PCR might serve as a bio-predictor of response to platinum-based induction chemotherapy for epithelial HNCs.

• Journal of the Korean Society of Tobacco Science
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• v.24 no.2
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• pp.113-120
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• 2002

This study was conducted to determine the smoke component changes by adding oriental, reconstituted, and expanded tobacco leaves. 7 different cigarette brands which were mixed with flue-cured, burley, oriental, reconstituted and expanded tobacco leaves were used for this study. 64 kinds of smoke components which were 6 of general components, 34 of semi-volatile and volatile components, 9 of acid components, and 15 of phenolic components were analyzed. All smoke components of mainstream smoke were changed by the different branding. As Tar, nicotine, ammonia, pH, all of acid compounds(except lacatic and glycolic acid) were decreased; HCN, levoglucosame, 4-vinyl phenol, 4-vinyl catechol, quinic acid-r-lactone, acetaldehyde, 2,3-butadiene, stylene were increased by adding oriental tobacco leaves. When the reconstituted tobaccos were added to 20%, the concentration of nicotine, all of acid compounds(except lactic. glycolic, palmitic acid) and all of phenol compounds were reduced; the concentration of ammonia, HNC, CO, aeconitrile, benzene, 2-butanone, moth-acrolene, butyronitrile, stylene, o-xylene were increased. As decreasing ammonia, pH, nicotine, all of acid compounds, all of phenol compounds, Isoprene, acetonitrile, 2-methyl-2-butene, 1,3-pentadiene, 2-nlethyl furane, ethylene cyclopentanone, ethyl bezene; increasing CO concentration were followed by adding expanded tobacco leaves.