• Korean journal of food and cookery science
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• v.14 no.2
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• pp.140-147
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• 1998

The rheological properties of dough made from composite flour containing 30% of buckwheat flour with 80% of extraction rate and 70% of wheat flour, with addition of vital wheat gluten and/or gums, were studied for the development of buckwheat bread. From the farinograph data, water absorption, development time, and stability of the dough decreased as the amount of buckwheat flour increased. However, the addition of gluten increased the water absorption and development time but decreased the weakness of the dough. The use of xanthan gum showed a stability-increasing effect. From the extensograph data, extension and strength of the dough decreased with increasing amount of buckwheat flour, but resistance to extension increased. The addition of gluten increased the extension and strength of the dough, but decreased the resistance to extension. Guar and xanthan gum added at 0.2% level had little effect on extensograph data of the dough. Overall, addition of, vital wheat gluten improved the properties of buckwheat bread dough better than water-soluble gums.

• Fibers and Polymers
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• v.7 no.2
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• pp.129-138
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• 2006

Using a strain-controlled rheometer, the steady shear flow properties of aqueous xanthan gum solutions of different concentrations were measured over a wide range of shear rates. In this article, both the shear rate and concentration dependencies of steady shear flow behavior are reported from the experimentally obtained data. The viscous behavior is quantitatively discussed using a well-known power law type flow equation with a special emphasis on its importance in industrial processing and actual usage. In addition, several inelastic-viscoplastic flow models including a yield stress parameter are employed to make a quantitative evaluation of the steady shear flow behavior, and then the applicability of these models is also examined in detail. Finally, the elastic nature is explained with a brief comment on its practical significance. Main results obtained from this study can be summarized as follows: (1) Concentrated xanthan gum solutions exhibit a finite magnitude of yield stress. This may come from the fact that a large number of hydrogen bonds in the helix structure result in a stable configuration that can show a resistance to flow. (2) Concentrated xanthan gum solutions show a marked non-Newtonian shear-thinning behavior which is well described by a power law flow equation and may be interpreted in terms of the conformational status of the polymer molecules under the influence of shear flow. This rheological feature enhances sensory qualities in food, pharmaceutical, and cosmetic products and guarantees a high degree of mix ability, pumpability, and pourability during their processing and/or actual use. (3) The Herschel-Bulkley, Mizrahi-Berk, and Heinz-Casson models are all applicable and have equivalent ability to describe the steady shear flow behavior of concentrated xanthan gum solutions, whereas both the Bingham and Casson models do not give a good applicability. (4) Concentrated xanthan gum solutions exhibit a quite important elastic flow behavior which acts as a significant factor for many industrial applications such as food, pharmaceutical, and cosmetic manufacturing processes.

• Korean Journal of Food Science and Technology
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• v.28 no.3
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• pp.538-544
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• 1996

A highly viscous biopolymer from alkali-tolerant Bacillus sp. was purified and its rheological properties were studied. 1% (w/v) solution of purified biopolymer showed pseudoplastic fluid behavior with the yield stress similar to those of xanthan and guar gum, and its consistency index was exponentially dependent on concentration and temperature. The concentration dependency of consistency index exhibited two rectilinear plots with different slopes at 1% concentration and pseudoplastic property increased with the increase of biopolymer concentration. The biopolymer solution exhibited a low temperature dependency and the activation energy of flow was 1.16 kacl/g mol. The apparent viscosity was very dependent on the change of pH and the addition of salt. However, no organic solvent effects were observed effects of viscosity synergism with the addition of viscosifier were not observed.

• Korean Journal of Clinical Laboratory Science
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• v.42 no.1
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• pp.22-31
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• 2010

The most common sources of biological trace material which are found in crime scene are the human bloodstains. Reliable identification in the forensic casework is important as it provides crucial insights into crime scene reconstruction and can thus contribute towards solving crimes. Blood-stains are routinely tested in forensic practise using various methods including the leucomalachite green (LMG) test, Kastle-Meyer phenolphthalein test, tetramethylbenzidine test, orthotolidine test, or the luminol chemoluminescence test with the latter cleaning attempts. All these presumptive thus indicative but not identifying tests take advantage of the peroxidase-like activity of the heme unit of the hemoglobin molecule in human blood. Therefore, false-positive results can be caused by the presence of strong oxidants, such as chlorine-containing detergents or by true peroxidases (e.g., from plants). In this study, composition for Gum guaiac was evaluated for the forensic identification of bloodstain and compared with the LMG. The sensitivity and specificity of the composition for Gum guaiac were examined more stable in bloodstain. The positive of Composition for Gum guaiac shown even with the 100,000-fold diluted bloodstain, which was no difference in comparison with LMG test. It was shown that composition for Gum guaiac was very stable to resist boiling for 20 minutes and the effect of bacteria did not affect the genetic analysis as well. The above result of the crime scene investigation, composition for Gum guaiac is easily expected to help identifying bloodstain in the evidences.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.71-71
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• 2017

하천에서 평수기 유량측정은 도섭법을 이용하기 위한 지점식 측정보다는 초음파 도플러 유속계(ADCP, Acoustic Doppler Current Profiler)를 보트에 탑재하여 운용하는 측정 방식이 점차 일반화되고 있다. ADCP는 초음파의 도플러효과를 이용하여 수심이나 횡방향의 유속 분포를 측정할 수 있는 측정 장비로 일반적으로 사용되는 down-looking ADCP는 수심방향의 유속분포와 수심을 측정하여 보트의 이동속도와의 벡터 내적을 이용하여 유량을 산정하게 된다. 그러나, 이동식 ADCP 유량 측정 성과의 불확도는 제공되지 않고 있는 상황인데, 이는 불확도 산정 표준안 미비, 유속 및 수심 등 측정 요소의 관측 환경 별 불확도 정보 부족, 불확도를 산정할 수 있는 툴의 부재 등에 기인한다. 본 연구에서는 이동식 ADCP 불확도 산정 표준안을 개발하고 현장 실험을 통해 불확도 요인에 대한 규명, 불확도를 편리하게 산정할 수 있는 툴을 개발하고자 하였다. 불확도 산정 표준안으로 최근 WMO를 위시한 국제적으로 하천 유량 측정 불확도 표준안으로 채택되고 있는 GUM(Guide to the Expression of Uncertainty Measurement)을 기반으로 이동식 ADCP 유량 산정 알고리즘을 적용하여 불확도 적용 기법을 개발하였다. GUM 표준안을 기반으로 유량 측정불확도를 산정하기 위한 불확도 요인분석은 실규모 하천의 특성을 대부분 모의할 수 있는 한국건설기술연구원의 안동하천실험센터에서 수행된 실험자료를 기반으로 다양한 인자들에 대한 요소 별 불확도 분석을 수행하였다. GUM 표준안에 의하면 불확도 요인들은 오차전파의 법칙에 기반하여 전체 불확도에 전파되며, 이렇게 합성된 불확도는 t-분포의 신뢰수준 95%일 경우의 보정계수 2를 곱하여 최종적으로 확장불확도를 산정하게 된다. 이동측정방식의 ADCP의 경우 GUM 표준안에 적용하여 불확도를 평가하기 위해서 사용되는 수식이 방대하고, 매우 복잡하기 때문에 이를 실무자가 평가하기에는 한계가 있다. 이에 따라 본 연구에서는 ADCP의 유량 측정불확도를 보다 편리하게 평가하기 위하여 ADCP 유량 측정불확도 평가 소프트웨어인 AQUA(ADCP Discharge Uncertainty Assesment)를 개발하였으며, 이를 통해 실무자나 연구자들이 ADCP의 불확도 평가에 보다 편리하게 접근할 수 있을 것이라 판단된다.

• The korean journal of orthodontics
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• v.51 no.5
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• pp.313-320
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• 2021

Objective: The purpose of this study was to evaluate the effects of chewing gum and low-level laser therapy in alleviating orthodontic pain induced by the initial archwire. Methods: Patients with 3-6 mm maxillary crowding who planned to receive non-extraction orthodontic treatment were recruited for the study. Sixty-three participants (33 females and 30 males) were randomly allocated into three groups: laser, chewing gum, and control. In the laser group, a gallium aluminum arsenide (GaAlAs) diode laser with a wavelength of 820 nm was used to apply a single dose immediately after orthodontic treatment began. In the chewing gum group, sugar-free gum was chewed three times for 20 minutes-immediately after starting treatment, and at the twenty-fourth and forty-eighth hours of treatment. Pain perception was measured using a visual analog scale at the second, sixth, and twenty-fourth hours, and on the second, third, and seventh days. Results: There were no statistically significant differences between the groups at any measured time point (p > 0.05). The highest pain scores were detected at the twenty-fourth hour of treatment in all groups. Conclusions: Within the limitations of the study, we could not detect whether low-level laser therapy and chewing gum had any clinically significant effect on orthodontic pain. Different results may be obtained with a higher number of participants or using lasers with different wavelengths and specifications. Although the study had a sufficient number of participants according to statistical analysis, higher number of participants could have provided more definitive outcomes.

• The korean journal of orthodontics
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• v.51 no.5
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• pp.346-354
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• 2021

Objective: To compare the effectiveness of ibuprofen, acetaminophen, and chewing gum for orthodontic pain relief and to assess if chewing gum can be a non-pharmacological alternative for orthodontic pain relief. Methods: The study enrolled 106 patients of both sexes, aged ≥ 12 years, with body weight > 50 kg, and mild-to-moderate dental crowding in the upper arch. After randomization and allocation concealment, the intervention groups were either administered with ibuprofen (400 mg) or acetaminophen (500 mg) or chewed sugar-free chewing gum immediately after initial archwire placement and every 6 hours for 1 week if the pain persisted. The control group did not receive any pain relief. The pain was assessed on a 100-mm visual analog scale at rest and while biting down at T1 (2 hours), T2 (24 hours), T3 (2 days), T4 (3 days), T5 (7 days), and T6 (21 days). Statistical analyses were performed using the Kruskal-Wallis and post-hoc Mann-Whitney U tests (α = 0.05). Results: The chewing gum group experienced more pain relief than the ibuprofen group at while biting down at T3 (p = 0.04) and at rest at T4 (p < 0.001). The chewing gum group reported more pain relief than the acetaminophen and control groups while biting down at T3 (p = 0.03 and p = 0.0006, respectively) and T4 (both p < 0.001). Conclusions: Chewing gum can be a non-pharmacological alternative for orthodontic pain relief at 2 and 3 days after initial archwire placement.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.18-18
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• 2021

초음파 도플러 유속계(ADCP)는 초음파를 이용하여 하천의 유속 및 수심을 측정하는 장비로 기존의 지점식 유속계와는 다르게 수심방향 유속분포와 수심을 한번에 측정하게 되며, 보트를 이용하여 하천을 횡단하게 되면 기존의 유속-면적법을 이용하는 방식보다 간편하고 빠르게 한 단면의 유량을 측정할 수 있다. 이와 같은 이점으로 인해 국내뿐만 아니라 해외에서도 대하천에서부터 중·소규모의 하천까지 다양한 범위에서 유량을 측정하는 장비로서 사용되어지고 있다. ADCP의 측정 유량은 유량관측소에서 수위-유량관계식을 구축할 때 사용하고 있으며, 이렇게 제공되는 유량은 하천의 중·장기 계획 수립, 수공구조물의 설계 및 수문·수리분야의 연구에 활용되고 있다. 하지만 ADCP의 유량측정은 ADCP의 미측정 영역의 유량 추정, ADCP 잠김깊이의 정확도, 하안에서의 고정 측정시간 등 ADCP의 측정 과정이나, 유량 추정 방법에 따라 영향을 받게 되며. 이외에도 하천의 수심, 하상의 상태와 같은 측정 조건에 따라서도 정확도의 변화가 발생할 수 있다. 측정결과의 정확성을 향상시키고, 신뢰도가 높은 자료를 제공하기 위해서는 ADCP의 유량 측정결과에 대한 불확도를 발생시키는 요인들에 대한 분석과 이를 감소시킬 수 있는 방법을 찾는 것이 중요하다. 1993년 ISO, BIPM, IFCC 등 6개 기구에서는 측정불확도를 산정하기 위한 측정불확도 산정 지침서(GUM, Guide to the expression of Uncertainty of Measurement)를 제시하였다. GUM 표준안은 측정과정에서 발생하는 다양한 불확도 요인들을 불확도 전파법칙을 통해 전체 불확도를 산정하는 방식으로 WMO와 ISO의 유량 측정분야에서도 GUM 표준안을 측정불확도 산정 기준으로 공인하여 사용하고 있다(JCGM 100, 2008; ISO 25377, 2020). 이에 본 연구에서는 GUM 표준안을 이용하여 ADCP로 측정된 유량의 측정불확도를 산정하는 방법을 개발하고 각 요인들에 대한 실험 및 분석을 진행하였다. ADCP의 측정 정확도를 분석하기 위한 실험은 자연에 가까운 형상을 모의하고 있고, 소하천 규모를 갖고 있는 하천연구센터에서 수행하였으며, 요인들에 대한 분석 방법 및 총 불확도를 계산하는 방법에 대하여 제시하였다.

• Water for future
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• v.49 no.12
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• pp.23-31
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• 2016

• Journal of Oral Medicine and Pain
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• v.24 no.4
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• pp.347-359
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• 1999

The purpose of this study was to investigate the effect of pilocarpine containing chewing gum on anti-microbial components in whole saliva of xerostomic patients, The objective xerostomic patients were instructed to use 5mg-pilocarpine containing chewing gum for 20minutes three times per day, and the author measured the flow rates of unstimulated whole saliva and stimulated whole saliva at the beginning the treatment, 1,2,3, and 4 weeks after. The concentration and flow rate of anti-microbial components in whole saliva were quantitated by enzyme-linked immunosorbent assay(ELISA). The obtained results were as follows: 1. There were significant increase in the unstimulated and stimulated whole salivary flow rate after using pilocarpine-containing chewing gum in xerostomic patients. 2. The concentrations of IgA in the unstimulated and stimulated whole saliva showed increasing pattern but, no significant changes, arid the flow rates of IgA in the unstimulated and stimulated whole saliva showed significant increase after using pilocarpine-containing chewing gum in xerostomic patients. 3. The concentrations of IgM in the unstimulated and stimulated whole saliva showed increasing pattern but, no significant changes, and the flow rates of IgM in the unstimulated and stimulated whole saliva showed significant increase after using pilocarpine-containing chewing gum in xerostomic patients. 4. The concentrations of lactoferrin in the unstimulated and stimulated whole saliva showed no significant changes, and the flow rates of lactoferrin in the unstimulated and stimulated whole saliva showed significant increase after using pilocarpine-containing chewing gum in xerostomic patients. 5. The concentrations of lysozyme in the unstimulated and stimulated whole saliva showed no significant changes, and the flow rates of lysozyme in the unstimulated whole saliva showed significant increase, but in stimulated whole saliva showed no significant changes after using pilocarpine-containing chewing gum in xerostomic patients.