• Title/Summary/Keyword: retention time

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Development of Analytical Method of Organophosphates in Sea water by Finger Printing Fluorescence Spectroscopy (형광분석을 이용한 지문방식의 해수중 유기인의 분석 방법)

  • PARK Mi-Ok
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.30 no.3
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    • pp.377-387
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    • 1997
  • Primary fluorescence characteristics of ten standard solutions of organophosphates, sea water, and water from agricultural land were investigated by fluorescence contour. All the standard solutions of organophosphates has shown characteristics countours. Their emission maxima were shown between 296 nm and 437 nm. According to their numbers of emission maxima on the fluorescence contours, the organophosphates can be categorized in two different groups. Ateric and Diazinon are the first group with two emission maxima. DDVP with other seven standard organophosphates belong to the second group. The second group has two subgroups. One is characterized by the similar emission and excitation maxima, which are 310 nm and 280 nm, respectively. Those are DDVP, Hinosan, Kitazin, Locsion, Meta. The other sub-group shows quite different emission and excitation maxima from the first sub-group. They are Monopho, Thaconyl and Gropho and their emisson maxima were in far longer (437 nm) or shorter wavelength (296 nm). From agricutural samples, one of the investigated organophosphates was detetected by its characteristic retention time $(t_r=12min)$. HPIC-fluorescence data gave an additional parameter for differentiation between two organophosphates which has similar excitation and emission maxima.

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Physicochemical Characteristics and Sugar-snap Cookie Potentialities of Korean Wheats (한국산 밀의 이화학적 특성과 sugar-snap cookie의 제조적성)

  • Chang, Hak-Gil;Kim, Jeong-Yeon
    • Korean Journal of Food Science and Technology
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    • v.36 no.5
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    • pp.754-760
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    • 2004
  • Physicochemical properties and suitability of domestic wheat varieties for production of sugar-snap cookie were examined. Four kinds of commercially available wheat flour and six kinds of other domestic wheat varieties were tested. Domestic wheat varieties had protein contents ranging 7.7 to 11.5%, alkaline water retention capacity (AWRC) of 54.6 to 65.2%, Pelshenke values of 17 to 31 min, and sedimentation values of 19.6 to 30.8 mL. Peak viscosity range of Korean wheat flours measured by Rapid Visco Analyser was from 134.4 to 346.3 unit. Diameter of cookies fer US soft wheat flour was 7.8 cm and domestic wheat flours ranged from 7.2 to 7.9 cm. Cookie spread factors for Alchanmil, Tapdongmil, and Woorimil flours were higher than those of other flours. Protein content had significantly high correlation coefficient of $r=0.892^{**}$ with sedimentation value, and showed negative correlation with cookie diameter, spread factor, and top grain score. AWRC values had significantly high correlation coefficient of $r=-0.736^{**}$ with cookie diameter. Spread factor of cookie showed positive correlation with top grain score.

Detection of Undeclared Betamethasone Derivatives in Cosmetic Products Labeled to Contain Zinc Pyrithione as the Active Ingredient (아연피리치온을 유효성분으로 표기한 화장품류에서 미표기 성분인 베타메타손 유도체의 검출)

  • Lee, Jeong-Pyo;Park, Sung-Hwan;Yang, Seong-Jun;Kim, Sun-Mi;Son, Kyung-Hun;Yun, Mi-Ok;Choi, Sang-Sook
    • Journal of the Society of Cosmetic Scientists of Korea
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    • v.35 no.1
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    • pp.11-17
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    • 2009
  • Betamethasone propionate, an anti-inflammatory glucocorticosteroid, was detected in cosmetics with no indication on the label of this compound as an ingredient. The product was formulated as a topical spray or shampoo and labeled to contain zinc pyrithione as the active ingredient. A thin-layer chromatographic analysis was carried out on silica gel plates to provide a first indication about the presence of a compound with steroid structure and reactivity; then high-performance liquid chromatography (HPLC) separation allowed the identification of the corticosteroid agent and its quantification. To identify the corticosteroid agent from these commercial samples we collected the fractions suspected to have ketol steroids by prep HPLC and identified the compound as betamethasone propionate by NMR and MS spectrometry. Then we synthesized the standard for the betamethasone 17-propionate and 21-propionate and quantitate the corticosteroids from the sample by HPLC with that standards. By this method we identified the corticosteroid compounds from some commercial cosmetics such as zinc pyrithione sprays. The finding of betamethasone propionate in the products was shown by comparison to an authenticated standard of betamethasone propionate by retention time on reverse-phase HPLC. Two of the tested products contained betamethasone propionate at the levels of 0.005 ${\sim}$ 0.02% and the others were free of betamethasone propionate.

Full mouth rehabilitation of the patient with severe tooth erosion using collarless porcelain fused to gold restorations: a case report (Collarless 금속 도재 보철물을 이용한 심한 erosion 환자의 전악수복 증례)

  • Song, Hee-Jin;Lim, Young-Jun;Kwon, Ho-Beom;Kim, Myung-Joo
    • The Journal of Korean Academy of Prosthodontics
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    • v.50 no.4
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    • pp.324-329
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    • 2012
  • Excessive tooth wear causes loss of tooth structure, disharmony of occlusal plane, functional and esthetic problems. Although the decrease of occlusal vertical dimension may be compensated by growth of alveolar bone, if the length of tooth is not enough for the retention of restoration, minimum increase of occlusal vertical dimension is required without discomfort of the patient. In this case, 33-year-old woman drinks more than 1 liter of soft drinks a day and has bruxism in night time, visited in Seoul National University Dental Hospital with chief complaint of generalized tooth wear and related esthetic and functional problems. It was considered as a loss of occlusal vertical dimension based on the accelerated tooth wear caused by erosion and bruxism and facial appearance, phonetic, esthetic, functional evaluations. It was planned to raise occlusal vertical dimension by provisional restoration two times for patient's adaptation, 3 mm and 2 mm each, total 5 mm. Confirming no discomfort and clinical symptom during total 16 weeks after restoration with provisional fixed restoration, it was restored with porcelain fused to gold crown and bridge. Because the patient was young woman, anterior teeth were restored with collarless porcelain fused to gold crown. This case presents that satisfactory esthetic and functional result by full mouth rehabilitation with increase of occlusal vertical dimension.

Rabbit maxillary sinus augmentation model with simultaneous implant placement: differential responses to the graft materials

  • Kim, Young-Sung;Kim, Su-Hwan;Kim, Kyoung-Hwa;Jhin, Min-Ju;Kim, Won-Kyung;Lee, Young-Kyoo;Seol, Yang-Jo;Lee, Yong-Moo
    • Journal of Periodontal and Implant Science
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    • v.42 no.6
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    • pp.204-211
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    • 2012
  • Purpose: This study was performed to establish an experimental rabbit model for single-stage maxillary sinus augmentation with simultaneous implant placement. Methods: Twelve mature New Zealand white rabbits were used for the experiments. The rabbit maxillary sinuses were divided into 3 groups according to sinus augmentation materials: blood clot (BC), autogenous bone (AB), and bovine-derived hydroxyapatite (BHA). Small titanium implants were simultaneously placed in the animals during the sinus augmentation procedure. The rabbits were sacrificed 4 and 8 weeks after surgery and were observed histologically. Histomorphometric analyses using image analysis software were also performed to evaluate the parameters related to bone regeneration and implant-bone integration. Results: The BC group showed an evident collapse of the sinus membrane and limited new bone formation around the original sinus floor at 4 and 8 weeks. In the AB group, the sinus membrane was well retained above the implant apex, and new bone formation was significant at both examination periods. The BHA group also showed retention of the elevated sinus membrane above the screw apex and evident new bone formation at both points in time. The total area of the mineral component (TMA) in the area of interest and the bone-to-implant contact did not show any significant differences among all the groups. In the AB group, the TMA had significantly decreased from 4 to 8 weeks. Conclusions: Within the limits of this study, the rabbit sinus model showed satisfactory results in the comparison of different grafting conditions in single-stage sinus floor elevation with simultaneous implant placement. We found that the rabbit model was useful for maxillary sinus augmentation with simultaneous implant placement.

Quality Characteristics of Domestic Strong Wheat Flour (시판 강력분 우리밀의 품질 특성)

  • Kwak, Han Sub;Kim, Mi Jeong;Kim, Oui-Woung;Kim, Sang Sook
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.46 no.5
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    • pp.616-621
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    • 2017
  • The objective of this study was to investigate the physicochemical properties of domestic strong wheat flour (DSWF). Three commercial DSWFs (D1, D2, and D3) were compared with imported strong wheat flour (ISWF). DSWFs had higher moisture content, crude protein content, lightness, and whiteness than ISWF. DSWFs showed lower solvent retention capacity and water absorption index than ISWF. DSWFs also showed significantly higher water solubility index than ISWF (P<0.05). Setback values by rapid visco analysis were significantly higher in D1 and D2 than in ISWF and D3, which means ISWF and D3 were better in retarding retrogradation. Differential scanning calorimetry results showed that ISWF required 6.2 J/g of energy for phase transition, whereas DSWFs needed 6.67~7.13 J/g. The farinograph results showed that ISWF had higher water absorption, longer dough stability time, and significantly higher softening of dough at 20 min than DSWF (P<0.05). Dough resistance and extensibility were higher in ISWF than in DSWFs.

COMPARISON OF MONOMER RELEASE FROM PIT AND FISSURE SEALANT FOLLOWING VARIOUS SURFACE TREATMENT (치면열구전색제의 광중합 후 표면 처리 방법에 따른 미반응 모노머 용리 비교)

  • Lee, Sang-Woo;Lee, Ju-Hyun;Seo, Hyun-Woo;Park, Ho-Won
    • Journal of the korean academy of Pediatric Dentistry
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    • v.33 no.1
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    • pp.70-76
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    • 2006
  • The aim of this study was comparison of effectiveness of surface treatment methods in reducing the oxygen-inhibited layer of a commercially available freshly polymerized, light cured dental sealant($concise^{TM}$, 3M, St Paul, USA). Surface treatment groups were consisted of no treatment(negative control group) and 3 experimental groups according to surface treatment of light-cured sealant. Experimental group I was 10 seconds' exposure to distilled water syringe, group II was 10 seconds' manual application using a cotton pellet wetted with 75% alcohol and group III was 10 seconds' prophylaxis with pumice/water slurry using rubber cup on a slow-speed handpiece. All specimens were immersed in 5ml distilled water and stored at 37c water bath for 10 minutes. All eluates were analyzed by HLPC for identification and quantitive analysis of monomers. The results of this study can be summarized as follows. 1. None of the chromatograms of the tested sealant displayed peaks with the same retention time as that of the standard solution, except for TEGDMA. 2. All surface treatment group had a statistically significant decrease of monomer release in comparison with no treatment group. 3. Removal effects of unreacted monomer in group III was statistically significant in comparison with group I and group II. These results revealed that mechanical method using pumice and rubber cup is the most effective in removing residual monomer and may be valuable to be used effectively in clinic.

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Analytical Method Validation of Quercetin in Changnyeong Onion Extract as a Functional Ingredient for Functional Health Food (건강기능식품 기능성원료로서 창녕양파추출액의 지표성분 Quercetin 분석법)

  • Jeon, Seon-Young;Jeong, Eun-Jeong;Baek, Jeong-Hwa;Cha, Yong-Jun
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.40 no.4
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    • pp.565-569
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    • 2011
  • Validation of quercetin as a marker compound in the standardization of Changnyeong onion extract developed for functional health food was attempted by analytical method. The specificity was satisfied with retention time and photo diode array (PDA) spectrum by analysis of quercetin using HPLC and comparison with standard compound. It showed a high linearity in the calibration curve as coefficient of correlation ($R^2$) of 0.9986, and the limit of detection (LOD) and limit of quantitation (LOQ) were 0.2 mg/L and 0.5 mg/L, respectively. Recovery rate test with quercetin concentration of 0.05, 0.075 and 0.1 mg/mL was revealed in the high range of 82.36~95.26%, 82.70~98.24% and 87.91~95.11%, respectively. The intra-day and inter-day precision in quercetin for Changnyeong onion extracts was 0.10~3.28% and 0.96~5.79%, respectively. Therefore, application of quercetin was validated in analytical method as a marker compound in Changnyeong onion extracts.

The Removal of Organics, Nitrogen and Phosphorus in Loop Reactor Using Fluidized Media (유동상 담체를 이용한 Loop Reactor에서 유기물 및 질소, 인 제거)

  • Seon, Yong-Ho
    • KSBB Journal
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    • v.24 no.4
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    • pp.353-360
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    • 2009
  • This study was accomplished using Anaerobic/Anoxic/Oxic upflow packed-bed column reactors with fixed media and Loop Reactor with fluidized media instead of Oxic reactor. The objectives of this study was to investigate the characteristics of organics, nitrogen and phosphorus removal from sewage with the HRT. The average removal efficiencies of $BOD_5$ and SS increase as increasing the hydraulic retention time (HRT) until 16 h of the HRT, and they were constant over 16 h of the HRT. The removal efficiency of $BOD_5$ in case of packed-bed reactor and Loop Reactor was about 86.6% and 90.9% respectively at 16 h of the HRT. The removal efficiency of SS in packed-bed reactor and Loop Reactor was about 78.0% and 88.2% respectively at 16 h of the HRT. The average removal efficiencies of $COD_{Cr}$ and $COD_{Mn}$ showed similar trends as those of $BOD_5$ and SS. At the HRT of 16 h, the removal efficiency of $COD_{Cr}$ in case of packed-bed reactor and Loop Reactor was 63.5%, 75.2% and that of $COD_{Mn}$ was 60.7%, 73.6% respectively. The average removal efficiencies of T-N and T-P increase as increasing the HRT. The removal efficiencies of T-N and T-P in Loop Reactor were 33.6% and 54.5% respectively at 16 h of the HRT and T-N and T-P were better removed in Loop Reactor. From this result, it was found that the performance of Loop Reactor was much higher than the performance of packed-bed reactor and the optimum HRT was 16 h.

Body Weight Changes and Lifestyle in Women within 1 year after Childbirth (여성의 출산 후 체중변화와 생활양식)

  • Chung, Chae Weon;Kim, Hyewon;Kim, Hyojung
    • Perspectives in Nursing Science
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    • v.13 no.2
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    • pp.88-95
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    • 2016
  • Purpose: Gestational weight gain and prepregnancy body weight are important factors of childbirth outcomes, which further cause obesity, metabolic diseases, or psychological problems later in women's lives. Changes in diet, westernized lifestyle, traditional postpartum care, and childbirth at older age are thought to be threats to proper weight management in Korean women of reproductive age. Public health and antenatal care need to focus on the proper body weight management of women by carefully planning pregnancy to postpartum periods. Purpose: This study explored the body weight changes from pregnancy to postpartum and the related characteristics in women within 12 months after childbirth. Methods: A cross-sectional, retrospective study was conducted with 102 Korean women within 12 months after childbirth. Data were collected using an online survey system, and a structured questionnaire available for electronic self-administration was modified to include demographics, obstetrical history, and body weight at 6 time points. The International Physical Activity Questionnaire and Eating Habit Measurement instruments were also used in data collection. A professional survey agency recruited the participants, and data were automatically saved and then analyzed. Results: The average age of the participants was 33.8 years, 48% were housewives and were well-educated. Seventy-two percent of the participants were primiparas and 82% had breastfed their babies. The body mass index (BMI) ranged from 17.3 to 27.8, indicating that 21.5% of the participants were overweight or obese. The mean gestational weight gain was 11.8 kg, and weight loss was apparent during the first 3 months postpartum. The mean decline in weight was 3.4 kg at one year after childbirth. Women wanted to lose 5.6 kg (range: 3~20 kg), however 44% of them reported that they had not engaged in any weight control efforts. Further, 72% of them reported having engaged in a low level of physical activity. Body weight was not associated with women's characteristics, physical activity score, and diet. Conclusion: Women's awareness of gestational weight gain, lifestyle modification, and the risk of prolonged weight retention should be promoted through the antenatal and women's healthcare systems. As pregnancy and childbirth are critical events that affect women's health, integrative education to ensure healthy transition to life after delivery is required.