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Vertical Alignment of Liquid Crystal on Film of Plant-based Polysaccharide Derivatives

  • Yeonsu Cho;Jihyeon Moon;DaEun Yang;Hyo Kang
    • Elastomers and Composites
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    • v.58 no.1
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    • pp.1-10
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    • 2023
  • In this study, we investigate the liquid crystal (LC) alignment of LC cells created from plant-based polysaccharide derivatives, such as guar gum. Guar gum films exhibit satisfactorily high optical transparency in the visible light region (400-750 nm). For example, the transmittance of polyimide films, which are the most typically used LC alignment layers, is 87%, whereas that of guar gum films deposited onto a glass substrate at a wavelength of 550 nm is approximately 99%. The observed LC alignment depends on the rubbing depth. For example, an LC cell comprising a guar gum film fabricated via rubbing at rubbing depths of 0.1, 0.2, 0.3, and 0.4 mm exhibits a planar LC alignment, whereas it exhibits a vertical LC alignment at a rubbing depth of 0.5 mm. Additionally, the LC alignment is shown to be correlated with the total surface energy of the guar gum films. When the total surface energy of a rubbed guar gum film exceeds 58.10 mJ/m2, an LC cell comprising the guar gum film exhibits a stable and vertical LC alignment. Therefore, guar gum can be used to realize the vertical alignment system of LC via a simple adjustment of the rubbing depth.

Comparative Study on the Effectiveness of Pilocarpine in Xerostomia according to the Method of Administration (필로카핀 투여 방법에 따른 구강 건조증 환자의 치료 효과에 관한 연구)

  • Sun-Kyung Lee;Ki-Yong Hyun;Sung-Woo Lee
    • Journal of Oral Medicine and Pain
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    • v.19 no.2
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    • pp.25-45
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    • 1994
  • The purposes of this study were to investigate the effect of pilocarpine-containing chewing gum for the treatment of xerostomia and to compare the effect of pilocarpine-containing chewing gum with that of pilocarpine oral administration. The 20 subjective and objective xerostomic patients were included in this study and divided into 3 groups. Five subjects were included in gum base chewing group, 10 in pilocarpine-containing gum chewing, and 5 in pilocarpine oral administration. The author measured unstimulated whole salivary flow rate, stimulated parotid salivary flow rate, pH of resting whole saliva, viscosity of stimulated whole saliva, and subjective symptoms and discomforts using VAS(visual analogue scale) at the beginning of the experiment. And the author investigated the changes of these factors at 1, 2, 3, and 4 week after. The obtained results were as follows : 1. There were significant increases in the unstimulated whole salivary flow rate in pilocarpine-containing gum chewing and pilocarpine oral administration groups. But there was no significant difference between pilocarpine-containing gum chewing and pilocarpine oral administration groups. 2. There was a significant increase in the stimulated parotid salivary flow rate in pilocarpine- containing gum chewing group. But there was no significant difference between pilocarpine- containing gum chewing and pilocarpine oral administration groups. 3. The change of salivary pH showed the increasing pattern in all groups. But there was no significant difference among groups. 4. There were no significant changes in the values of salivary viscosity in all groups through the experimental period. 5. There were significant decreases of VAS(visual analogue scale) in the degree of subjective symptoms and discomforts in pilocarpine-containing gum chewing and pilocarpine oral administration groups. But there was no significant difference between pilocarpine- containing gum chewing and pilocarpine oral administration groups.

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Correlating the Fineness and Residual Gum Content of Degummed Hemp Fibres

  • Beltran, Rafael;Hurren, Christopher J.;Kaynak, Akif;Wang, Xungai
    • Fibers and Polymers
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    • v.3 no.4
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    • pp.129-133
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    • 2002
  • It is well known residual gum exists in degummed or rotted hemp fibers. Gum removal results in improvement in fiber fineness and the properties of the resultant hemp yams. However, it is not known what correlation if any exists between the residual gum content in retted hemp fibers and the fiber fineness, described in terms of fiber width in this paper. This study examined the mean width and coefficient of variation (CV) of fiber width of seventeen chemically rotted hemp samples with reference to residual gum content. The mean and CV of fiber width were obtained from an Optical fiber diameter analyser (OFDA 100). The linear regression analysis results show that the mean fiber width is directly proportional to the residual gum content. A slightly weaker linear correlation also exists between the coefficient of variation of fiber width and the residual gum content. The strong linear co-relation between the mean of fiber width and the residual gum content is a significant outcome, since testing for fiber width using the OFDA is a much simpler and quicker process than testing the residual gum content. Scanning Electron Microscopy (SEM) reinforces the OFDA findings. SEM micrographs show a flat ribbon like fiber cross-section hence the term \"fiber width\" is used instead of fiber diameter. Spectral differences in the untreated dry decorticated skin samples and chemically treated and subsequently carded samples indicate delignification. The peaks at $1370cm^{-1}$, $1325cm^{-1}$, $1733cm^{-1}$, and $1600cm^{-1}$ attributed to lignin in the untreated samples are missing from the spectra of the treated samples. The spectra of the treated samples are more amine-dominated with some of the OH character lost.cter lost.

AN OVERVIEW OF BDF2 GAUGE-UZAWA METHODS FOR INCOMPRESSIBLE FLOWS

  • Pyo, Jae-Hong
    • Journal of the Korean Society for Industrial and Applied Mathematics
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    • v.15 no.3
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    • pp.233-251
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    • 2011
  • The Gauge-Uzawa method [GUM] in [9] which is a projection type algorithm to solve evolution Navier-Stokes equations has many advantages and superior performance. But this method has been studied for backward Euler time discrete scheme which is the first order technique, because the classical second order GUM requests rather strong stability condition. Recently, the second order time discrete GUM was modified to be unconditionally stable and estimated errors in [12]. In this paper, we contemplate several GUMs which can be derived by the same manner within [12], and we dig out properties of them for both stability and accuracy. In addition, we evaluate an stability condition for the classical GUM to construct an adaptive GUM for time to make free from strong stability condition of the classical GUM.

Quality and Palatability of Beef Patty Containing Gums (Gum류를 첨가한 우육 Patty의 품질 및 기호성)

  • 송형익;박충균;남주현;양종범;김동술;문윤희;정인철
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.31 no.1
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    • pp.64-68
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    • 2002
  • This study was conducted to investigate en the quality characteristics and palatability of beef patties containing various gums such as carrageenan, xanthan gum and guar gum. Moisture contents of raw and cooked patties of control were lower than those of the gum-added Patties, and fat content of control patty was higher than that of the gum-added patties. Protein content of gum-added patties was higher than that of the control patty. Hunter's $L^{*}$ value (lightness) of raw patty of control was higher than that of the gum-added patties, hut Hunter's $a^{*}$(redness) and $b^{*}$(yellowness) values were not different among four kinds of patties. Hunter's $L^{*}$, $a^{*}$ and $b^{*}$ values of cooked patties showed no significant difference among patties. Cooking yield, fat retention and water holding capacity of gum-added patties were higher than those of the control patty. Hardness and chewiness of patties showed no significant difference among patties, but gumminess of gum-added patties was higher than that of the control patty. Aroma, juiciness and palatability were not different among four kinds of patties, but texture of gum-added patties was higher than that of the control patty.l patty.tty.

Physicochemical and Sensorial Properties of Probiotic Yogurt as Affected by Additions of Different Types of Hydrocolloid

  • Bahrami, Masoud;Ahmadi, Dariush;Alizadeh, Mohammad;Hosseini, Fakhrisadat
    • Food Science of Animal Resources
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    • v.33 no.3
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    • pp.363-368
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    • 2013
  • The main attributes of yogurt that affect consumer satisfaction are taste, consistency, and a firm texture. This study evaluates the influence of xanthan gum, barley beta-glucan, and guar gum in concentrations of 0.05%, 0.1%, 0.2%, and 0.3% on probiotic yogurt. The set-type yogurt samples were prepared by using raw cow's milk. The statistical analysis showed that none of these gum additions had any marked effect on pH, titratable acidity, total solids content, and probiotic bacteria counts of yogurt samples. Evaluations for syneresis and water-holding capacity (WHC) in the yogurt samples were affected by the type and concentration of the stabilizer. Yogurts treated with 0.1% xanthan gum and 0.3% beta-glucan recorded the highest WHC and the least syneresis. The largest amount of gel firmness was recorded in yogurt samples treated with 0.2% xanthan gum and 0.3% beta-glucan. Yogurt samples treated with 0.1% xanthan gum and 0.3% beta-glucan were considered acceptable by trained panelists and gained the highest scores in sensory evaluations. The correlation coefficient between the amount of syneresis, WHC and stiffness of texture was significant compared to scores for sensory evaluation (p<0.01). Results for effects of guar gum on the tested parameters were contrary to the results expected from a gum. According to this study, the use of xanthan gum and beta-glucan are highly recommended for low-fat yogurt production.

Effects of Some Natural and Synthetic Gums on the Foaming Properties of Sodium Caseinate (몇가지 천연 및 합성 고무질이 Sodium Caseinate의 거품성에 미치는 영향)

  • 양승택
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.22 no.6
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    • pp.743-752
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    • 1993
  • To elucidate the effects of natural gums, i.e. carrageenan, locust bean gum and xanthan gum and synthetic gums, i.e. carboxymethyl cellulose(CMC) and methyl cellulose(MC) on the foaming properties of sodium caseinate, surface tension, absolute viscosity, turbidity, foaming ability, foam stability, and heat stability of the foams of the caseinate solutions with added gums were examined. The surface tension of sodium caseinate solution(5%) adding to gums at pH 4.0 and 5.0 were higher than those at pH 7.0 and 8.0. The viscosities of the solutions adding to gums(0.1, 0.2, 0.3 and 0.5%) ap pH 4.0, 5.0, 7.0 and 8.0 were 2.4~170.0, 2.5~190.0, 5.3~180.0 and 6.3~99.0 cps, respectively. Especially xanthan gums predominantly increased the viscosity. Turbidities were 97.3~98.2 at pH 4.0 and 5.0 and 93.0~95.8 at pH 7.0 and 8.0. Foaming abilities of the solution adding to xanthan gum, carrageenan and locust bean gum were increased, while those of CMC and MC were decreased. Additions of xantham gum, CMC and MC increased the foam stability, especially xanthan gum did predominantly. Xanthan gum, MC and locust bean gum were more effective than CMC and carrageenan for heat stability. For improving the foaming properties of sodium caseinate xanthan gum were best of five kinds of gums. Surface tensions and turbidities of the solution were related to foaming ability, and the viscosities were related to foam stability and heat stability.

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Improvements of Strength and Retention of Cotton Handsheet by Additives(II) -The durability test of cotton handsheet with additives (면 수초지의 지력 및 보류 향상을 위한 첨가제의 적용(제2보) -첨가제에 따른 면 수초지의 내구성 시험)

  • Cho, Yu-Je;Kim, Kang-Jae;Eom, Tae-Jin
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.46 no.1
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    • pp.29-38
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    • 2014
  • Guar gum is added to the pulp suspension at the suction side of the fan pump just before the sheet is formed on either a fourdrinier or cylinder machine. Guar gum replaced and supplements these hemicelluloses in paper bonding with many advantages, which include improved sheet formation with a more random distribution of pulp fibers. But, guar gum has serious storage problem. This material has easily decayed after High-temperature conditions such as summer. In this study, various properties of cotton handsheet were measured to solve the problem of deformation while storing guar gum and to improve the durability. After aging, which is one of the durability tests, cotton handsheet with 0.2% and 0.3% of A-PAM showed improved mechanical properties and bursting index and folding endurance of cotton handsheet with 0.3% of A-PAM were similar to those with guar gum. The yellowness loss of cotton handsheet with synthetic polymers was lower than those with guar gum.

Effects of Dietary Gum Phospholipid on Lipid Metabolism in Broiler Chicks

  • An, B.K.;Kang, C.W.;Nishiyama, H.;Iwata, T.;Tanaka, K.
    • Asian-Australasian Journal of Animal Sciences
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    • v.13 no.4
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    • pp.506-510
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    • 2000
  • This experiment was to determine the usefulness of gum safflower phospholipid as a feed ingredient. Forty female broiler chicks were divided into four groups and fed experimental diets containing following fats and oils; beef tallow (Tallow), the blend of safflower oil and palm oil (SP-oil), gum rapeseed phospholipid (Rap-PL), or gum safflower phospholipid (Saf-PL) for 21days. There were no differences in growth performances among the treatments. Abdominal fat weight tended to be reduced in the chicks fed. phospholipids. The activity of hepatic acetyl-CoA carboxylase was significantly reduced in the Rap-PL and Saf-PL as compared to that of Tallow. Feeding dietary phospholipids resulted in a slight reduction in total fat and triglyceride contents in the breast and thigh muscles. In addition, total fat and triglyceride contents in the thigh muscle were significantly decreased by dietary Saf-PL as compared to those of Tallow. These results suggested that dietary gum phospholipids, either from rapeseed or safflower, had desirable effects of lowing abdominal and muscle fats, and could be used as a feed ingredient for broiler diets.

Effect of guar gum on the blood composition in type-II diabetic subjects (Guar gum이 type-II 당뇨병 환자의 혈액성분에 미치는 영향)

  • 김은미
    • Journal of Nutrition and Health
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    • v.22 no.6
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    • pp.457-465
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    • 1989
  • Guar gum, a storage polysaccharide galactomannan was administered to 11 patients with type-II diabetes mellitus for 7 days and 3 weeks. They took 5 grams of guar gum 30 mins before each of three meals daily. The dinner 2-h postprandial values of their blood glucose were significantly lowered (P<0.05) after their guar treatment for 7 days compared with before taking guar gum. The 2-h postprandial values of blood glucose were significantly lowered(P<0.05) after 3 weeks of gual treatment compared with before taking guar gum. In an oral glucose tolerance test, their blood glucose values were significantly lowered at 120 mins(P<0.02) and 180 mins(P<0.05) after guar treatment. Total-lipid(P<0.01) and triglycerides(P<0.02) of their blood were significantly decreased and HDL-cholesterol(P<0.02) was significantly increased after guar treatment. HbA1C was significantly reduced (P<0.05) from 11.3% to 10.1% The body weight, total-cholesterol and insulin activity of the patients after guar treatment were not significantly changed and the satiety ratings of the patients with guar treatment was not significantly changed and the satiety ratings of the patients with guar treatment was not significantly changed, however, the subjects that answered from 'Want to eat but can wait' to 'No desire to eat' were 81.1%. It is concluded that guar gum improves their carbohydrate and lipid metabolism in Korean type-II diabetic subjects with high fiber diets.

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