• Title/Summary/Keyword: Membrane properties

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Effect of Amino Terminus of Gap Junction Hemichannel on Its Channel Gating (간극결합채널의 아미노말단이 채널개폐에 미치는 영향)

  • Yim Jaegil;Cheon Misaek;Jung Jin;Oh Seunghoon
    • Journal of Life Science
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    • v.16 no.1
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    • pp.37-43
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    • 2006
  • Gap junction is an ion channel forming between adjacent cells. It also acts as a membrane channel like sodium or potassium channels in a single cell. The amino acid residues up to the $10^{th}$ position in the amino (N)-terminus of gap junction hemichannel affect gating polarity as well as current-voltage (I-V) relation. While wild-type Cx32 channel shows negative gating polarity and inwardly rectifying I-V relation, T8D channel in which threonine residue at $8^{th}$ position is replaced with negatively charged aspartate residue shows reverse gating polarity and linear I-V relation. It is still unclear whether these changes are resulted from the charge effect or the conformational change of the N-terminus. To clarify this issue, we made a mutant channel harboring cysteine residue at the $8^{th}$ position (T8C) and characterized its biophysical properties using substituted-cysteine accessibility method (SCAM). T8C channel shows negative gating polarity and inwardly rectifying I-V relation as wild-type channel does. This result indicates that the substitution of cysteine residue dose not perturb the original conformation of wild-type channel. To elucidate the charge effect two types of methaenthiosulfonate (MTS) reagents (negatively charged $MTSES^-$ and positively charged $MTSET^+$) were used. When $MTSES^-$ was applied, T8C channel behaved as T8D channel, showing positive gating polarity and linear I-V relation. This result indicates that the addition of a negative charge changes the biophysical properties of T8C channel. However, positively charged $MTSET^+$ maintained the main features of T8C channel as expected. It is likely that the addition of a charge by small MTS reagents does not distort the conformation of the N-terminus. Therefore, the opposite effects of $MTSES^-$ and $MTSETT^+$ on T8C channel suggest that the addition of a charge itself rather than the conformational change of the N-terminus changes gating polarity and I-V relation. Furthermore, the accessibility of MTS reagents to amino acid residues at the $8^{th}$ position supports the idea that the N-terminus of gap junction channel forms or lies in the aqueous pore.

Large scale enzymatic production of chitooligosaccharides and their biological activities (키토산올리고당의 효소적 대량생산 및 생리활성)

  • Kim, Se-Kwon;Shin, Kyung-Hoon
    • Food Science and Industry
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    • v.53 no.1
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    • pp.2-32
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    • 2020
  • In recent years, significant importance has been given to chitooligosaccharides (COS) due to its potent notable biological applications. COS can be derived from chitosan which is commonly produced by partially hydrolyzed products from crustacean shells. In order to produce COS, there are several approaches including chemical and enzymatic methods which are the two most common choices. In this regard, several new methods were intended to be promoted which use the enzymatic hydrolysis with a lower cost and desired properties. Hence, the dual reactor system has gained more attention than other newly developed technologies. Enzymatic hydrolysis derived COS possesses important biological activities such as anticancer, antioxidant, anti-hypersentive, anti-dementia (Altzheimer's disease), anti-diabeties, anti-allergy, anti-inflammatory, etc. Results strongly suggest that properties of COS can be potential materials for nutraceutical, pharmaceutical, and cosmeceutical product development.

Characterization and Modification of Milk Lipids (유지방의 특성과 변화)

  • Yeo, Yeong-Geun;Choe, Byeong-Guk;Im, A-Yeong;Kim, Hyo-Jeong;Kim, Su-Min;Kim, Dae-Gon
    • Journal of Dairy Science and Biotechnology
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    • v.16 no.2
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    • pp.119-136
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    • 1998
  • The lipids of milk provide energy and many essential nutrients for the newborn animal. They also have distinctive physical properties that affect the processing of dairy products. Milk fat globules mainly consist of neutral lipids like triacylglycerols, whereas the globule membranes contain the complex lipids mostly, Phospholipids are a small but important fraction of the milk lipids and are found mainly in the milk fat globule membrane and other membranous material in the skim-milk phase. The milk fats of ruminant animals are characterized by the presence of relatively high concentrations of short-chain fatty acids, especially butyric and hexanoic acids, which are rarely found in milks of non-ruminants. The fatty acids of milk lipids arise from de novo synthesis in the mammary gland and uptake from the circulating blood. The fatty acid compositions of milks are usually complex and distinctive, depending on the nature of the fatty acids synthesized de novo in the mammary gland and those received from the diet in each species. The content and composition of milks from different species vary widely; presumably, these are evolutionary adaptations to differing environments. The actual process by which these globules are formed is unkonwn, but there are indications that triglyceride-containing vesicles which bleb from endoplasmic reticulum may serve as nucleation sites for globules. Recent studies on milk have centred on the manipulation of milk lipids to increase specific fatty acids, i.e. 20-carbon omega-3 fatty acids (eicosapentaenoic acid 20:5n3, decosahexaenoic acid 22:6n3) from marine sources because the fatty acids are closely associated with a decreased risk of coronary heart disease.

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The study of Tang Zong Hai's Medica-change thought (당종해(唐宗海)의 의역사상(醫易思想)에 관(關)한 연구(硏究))

  • Kim, Gi-Uk;Park, Hyeon-Guk
    • Journal of Korean Medical classics
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    • v.12 no.2
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    • pp.56-71
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    • 1999
  • 1. In the recohnition of cosmos true form, It is compared to the Boundless(無極) the Great Absolute(太極),Yin and Yang(兩儀) throungh the fertilazation process of spermatozoon and ovum. 2. It is explained that principle of unchange through the Form and Action(體 用) relation of the outer appearances and Number (象數) with matching the number of nine and ten to HaDoo(河圖) and RakSye(洛書). 3. Eigth divinations(八卦) being compared to the human body, Care presevation of pregnancy(養胎) is explained that head forms firstly(Gun-I 1乾一), secondly lung(Tae-E 兌二), heart(E-Sam 離三), liver(Jin-Sa 震四), gall bladder(Son-Oo 巽五), kidney(Gam-Yuk 坎六), intestines and stomach(Gan-Chill 艮七), lastly flesh forms(Gon-Pal 坤八). 4. It is explained that process of physiological change of $\ll$Nei Ching The Natural Truth in Ancient Times$\gg$(內經 上古天眞論) by matching boy at the age of 8 to Gan-divination(艮卦), and girl at the age of 7 to Tae-divination(兌卦). 5. The theory of six sons from Gun-Gon(乾坤六子論) is explained by relation of Apriority Eight-divination(先天八卦) obedience and disobedience-left and right. 6. It is explained that form of the human-body and the relationship of the Heart - the Kidney through the Gam(坎) Li(離) - divination 7. The effort of interpretating time and space of the Twelve Horary signs is explanined by season, direction, Five elements(五行), rise and decline, the Three Sum(三合), the Six Sum (六合), the six crash(六衡)'s relation. 8. the process of change from apriority(先天) to postery(後天) in the book of Changes(周易) is explanined by comparing to the phenomenum of nature and the human body. 9. The Energy Satus(氣位) are different from the direction of Eight-divination(八卦) and the properties of the good or bad of herb-drugs are differnt from the place of production. 10. The rightness of realizating the Overlapping-divinations(重卦) are compared to the phenomenum of nature through the Divination Virture(卦德). 11. The dependence-relations of The Twelve Meridians(十二經脈) are explained by-matching January with liver meridian, February with gall bladder meridian, march with heart pericardium meridiam, April with small intestine meridkan, August with lung spleen meridian, jury with stomach meridian, August with lung meridian, September with large intestine meridian, October with urinary bladder meridianm November with kidney meridian. December with triple energizer meridian throng The Twelve Byuk-divination. 12. The process of menstration cycle is explained by The Month symbolizing-divination(月候卦). 13. Through The Trade(交易) prove the reason of feverish sympotoms to use feverish Drug, mill sympotoms to use mill drug of prescription and Heart-Kidneys Consensus(心賢相交) and through The Change(變易), prove the chill and feverish consensus of forechill after feverish, fore feverish after chill and through. The Non-Change(不易) explain the reason of chill sympotoms to use feverish drug, feverish sympotoms to use chill drug of prscription. 14. Ho-divination(互卦) applicate Jxa Sa(佐使) herb drug match of Kun Sin Jwa Sa() theory. 15. According to the Hyo-position(爻位) match the ages, body form and drug by matching Ehight-divination(八卦) to the human body form and function in medicine and the book of Changes(周易) application emphasize the human body Ehight-divination(人身八卦). 16. Throgh the Order-divination(序卦) explain the rightness of Divination Image(卦象) arrangement and all things take shape by cosmo-energy conseusus(宇宙氣交). 17. Throgh the Mixing-divination(難卦) supply the vacancy of medicine and the book of Changes(周易) relationship in the foreword explian the human energy movements, sleep, vomitting, the energy arrival(逮氣), heart pericardium(心包), lung membrane(肺膜) etc.... Like the above sentence medicine and the book of Changes(周易) theory of scholar Tang on the viewpoint of easten-the way Western appliance(東道西器) researching abyss of medicine impart to descendants, so I think that the achievement of medicine and the book of Changes(周易) study is very excellant and I expect that the study Korean Oriental Medicine(韓醫學) theory by means of medicine the book of Changes(周易) reference, will be accelarated.

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Development of Immediate Face Lifting Technology for Reducing Wrinkles by Using Film-Forming Agent (피막 형성제를 이용한 즉각 리프팅 기술 개발)

  • Jun, Ji hyun;Ko, Eun ah;Han, Sang Gun;Kang, Hakhee
    • Journal of the Society of Cosmetic Scientists of Korea
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    • v.44 no.3
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    • pp.211-218
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    • 2018
  • Instant face lifting cosmetics contain various film forming agents for stretching the wrinkles on the skin surface. But, most of the film-forming polymers have sticky feels. And they are easily scrubbed out when skin is rubbed on. In this study, we focused on the influence of sodium silicate that has rapid film forming effect on skin surface and immediate wrinkle reducing effect. Sodium silicate, also known as water glass or soluble glass, is a compound containing sodium oxide and silica. Sodium silicate is a white powder that is readily soluble in water, producing an alkaline solution. Sodium silicate is stable in neutral and alkaline solutions. The sodium silicate solution hardens by drying in air and rapidly forms a thin film. When the solution is applied to the skin, the fine membrane coating is formed by water evaporation and ionic bond re-formation. It also makes the strong siloxane (Si-O) bonding on the skin surface. When these fixation properties are applied to cosmetics, they can give remarkable skin tightening effect. The sodium silicate solution can provide the lifting effect by forming a film on skin at a proper concentration. But, skin irritation may be caused with too high concentration of sodium silicate. We studied a desirable range of the sodium silicate concentration and combination with other fixatives for skin care formulation that has no sticky feels and no scrubbing out phenomenon. Immediate lifting gel was developed by using sodium silicate and various thickening systems. Among of the various thickeners, aluminum magnesium silicate showed the best compatibility with sodium silicate for rapid lifting effect. This instant physical lifting gel was confirmed as a low stimulating formula by skin clinical test.

Characteristics of Percutaneous Absorption of Glycol ethers (Glycol ethers에 대한 피부 투과 특성)

  • Lee, Han-Seob;Choi, Sung-Boo;Kim, Nac-Joo;Keun, Jang-Hyoun;Hwang, Hyun-Suk;Baek, Jung-Hun;Choi, Jin-Ho;Lee, Ho-Joon
    • Journal of the Korean Applied Science and Technology
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    • v.30 no.1
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    • pp.116-126
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    • 2013
  • Glycol ethers are a group of solvents based on alkyl ethers of ethylene glycol commonly used in paints. These solvents typically have a higher boiling point, together with the favorable solvent properties of lower-molecular weight ethers and alcohols. The word "Glycol ethers" was registered as a United States trademark by Union Carbide Corp. Typically, glycol ethers are found in pharmaceuticals, sunscreens, cosmetics, inks, dyes and water based paints. On the other hand, glycol ethers are used in degreasers, cleaners, aerosol paints and adhesives. Most glycol ethers are relatively water soluble, biodegradable and only a few are considered toxic. Therefore, they are unlikely to pose an adverse risk to the environment. Recent study suggests that occupational exposure to glycol ethers is related to low motile sperm count in men, but the finding has been disputed by others. In this study, skin permeation of 3 types glycol ethers were studied in vitro using matrix such as solvent and detergent. The absorption of glycol ethers[methyl glycol ethers(MC), ethyl glycol ethers(EC) and butyl glycol ethers(BC)] has been measured in vitro through rat skin. Epidermal membranes were set up in Franz diffusion cells and their permeability to PBS measured to establish the integrity of the skin before the glycol ethers were applied to the epidermal surface. Absorption rates for each glycol ethers were determined and permeability assessment made to quantify any irreversible alterations in barrier function due to contact with the esters. Types of glycol ethers in vitro experimental results on MC> EC> BC quickly appeared in the following order: skin permeation was beneficial to the skin permeation small molecular weight, the difference in chemical structure, such as hydrophilic, because with the partition coefficient and solubility mechanisms and passive diffusion to increase the speed at which transmission is considered.

Fabrication and Characterization of Transparent Conductive Film based on Bacterial Cellulose (Bacterial cellulose를 기반으로 하는 투명전도성막의 제조 및 특성평가)

  • Yim, Eun-Chae;Kim, Seong-Jun;Kee, Chang-Doo
    • Korean Chemical Engineering Research
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    • v.51 no.6
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    • pp.766-773
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    • 2013
  • A transparent film was fabricated based on bacterial cellulose (BC), BC has excellent physical strength and stability at high temperature and it is an environmental friendly flexible material. In order to improve the conductivity, silver nanowire (AgNW) and/or graphene were introduced to the BC membrane. The aspect ratio of the AgNW synthesized in this study was 214, with a length of $15{\mu}m$ and width of 70 nm. The higher aspect ratio improved the conductivity by reducing the contact resistance. The thermal and electrical properties of 7 types of films prepared were investigated. Each film was fabricated with rectangular shape ($2mm{\times}2mm{\times}50{\mu}m$). The films were scored with a net shape by a knife, and filled with AgNW and graphene to bestow conductivity. The film filled with AgNW showed favorable electrical characteristics with a thickness of $350{\mu}m$, electron concentration of $1.53{\times}10^{19}$, electron mobility of $6.63{\times}10^5$, and resistivity of 0.28. The film filled with graphene had a thickness of $360{\mu}m$, electron concentration of $7.74{\times}10^{17}$, electron mobility of 0.17, and resistivity of 4.78. The transmittances at 550 nm were 98.1% and 80.9%, respectively. All the films were able to light LEDs bulbs although their brightness differed. A thermal stability test of the BC and PET films at $150{\pm}5^{\circ}C$ showed that the BC film was more stable, whereas the PET film was quickly banded. From these results, it was confirmed that there it is possible to fabricate new transparent conductivity films based on BC.

Effects of Membrane-filtered Powder of Sunmul on the Quality Characteristics of Noodles (막분리한 순물의 농축분말 첨가가 국수의 품질에 미치는 영향)

  • Chung, Hai-Jung;Choi, Min-Hee;Kim, Woo-Jung
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.35 no.2
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    • pp.199-204
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    • 2006
  • This study was conducted to investigate the quality characteristics of noodles prepared with the addition of nanofiltered (NF) powder of sunmul. Noodles were prepared with different levels $(0\%,\;1.5\%,\;3\%\;and\;5\%,\;w/w)$ of NF powder and physico-chemical properties were examined. Results of rapid visco analyzer showed that peak, trough, final viscosity and set back decreased as the NF powder level increased. The weight and volume of cooked noodles increased with the addition of NF powder. Turbidity of soup also increased as the amount of NF powder increased, indicating higher cooking loss. The color of wet and cooked noodles became greenish yellow as the NF powder level increased. Hardness, springiness, gumminess and brittleness of cooked noodles decreased with the increasing amount of NF powder. Results of sensory evaluation showed that noodles prepared with up to $3\%$ addition of NF powder was considered to be as acceptable as noodles prepared without NF powder.

Survival Rate of Lactic Acid Bacteria and the Change of ${\beta}-Galactosidase$ Activity in Commercial Yogurts Under the Acidic Conditions (산성조건하에서 시판요구르트의 유산균 생존률과 ${\beta}-galactosidase$의 활성도)

  • Shin, Yong-Seo;Sung, Hyun-Ju;Kim, Dong-Han;Lee, Kap-Sang
    • Applied Biological Chemistry
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    • v.37 no.3
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    • pp.143-147
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    • 1994
  • Four samples of commercially manufactured yogurts (plain, drinking type) were purchased and evaluated their physico-chemical properties, buffering capacity. And the survival rate of lactic acid bacteria and their ${\beta}-galactosidase$ activity under the acidic conditions (in vitro) were investigated. The values of pH, titratable acidity, viscosity and viable cell counts of yogurts were $3.71{\sim}4.08$, $0.990{\sim}1.045%$, $256{\sim}3164\;cps.$ and $10^8{\sim}10^9\;cfu/ml$, respectively. The volume of 1.0 M-HCl required to reduce the pH of yogurt (50 ml) to minus 2 value was $3.58{\sim}4.33\;ml$. When commercial yogurts were incubated at $37^{\circ}C$ for 120 minutes under the acidic conditions (pH 3.5, 2.5, 1.5), the survival rates of lactic acid bacteria in yogurt were $3.5{\times}10^{-2}{\sim}3.6{\times}10^{-1}%$ at pH 2.5, $8.3{\times}10^{-5}{\sim}4.2{\times}10^{-3}%$ at pH 1.5, respectively, but there was no significant difference at pH 3.5. The remaining activities of ${\beta}-galactosidase$ were $9.4{\sim}36.2%$ at pH 2.5, $4.2{\sim}19.0%$ at pH 1.5, respectively. These results suggested that a significant number of lactic acid bacteria in yogurt might be destroyed in the hostile environment of the stomach, but ${\beta}-galactosidase$ activity from yogurt might be somewhat maintained probably due to the protecting effect by its cell wall and membrane.

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Preparation of Polymer Gel Electrolyte for EDLCs using P(VdF-co-HFP)/PVP (P(VdF-co-HFP)/PVP를 이용한 EDLC용 고분자 겔 전해질의 제조)

  • Jung, Hyun-Chul;Jang, In-Young;Kang, An-Soo
    • Applied Chemistry for Engineering
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    • v.17 no.3
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    • pp.243-249
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    • 2006
  • Porous polymer gel electrolytes (PGEs) based on poly(vinylidenefluoride-co-hexafluoropropylene) (P(VdF-co-HFP)) as a polymer matrix and polyvinylpyrolidone (PVP) as a pore-forming agent were prepared and electrochemical properties were investigated for an electric double layer capacitor (EDLC) in order to increase a permeability of an electrolyte into the PGE. Propylene carbonate (PC) and ethylene carbonate (EC) as plasticizers, and tetraethylammonium tetrafluoroborate ($TEABF_4$) as a supporting salt for the PGE were used. EDLC unit cells were assembled with the PGE and electrode comprising BP-20 and MSP-20 as activated carbon powders, Super P as a conducting agent, and P(VdF-co-HFP)/PVP as a mixed binder. Ion conductivity of PGEs increased with an increased PVP content and was the best at 7 wt% PVP, whereas electrochemical characteristics such as AC-ESR of unit cell were better in 3 wt%. And electrochemical characteristics of the unit cell with PGE were the best at a 33 : 33 weight ratio of PC to EC. Specific capacitance of a mixed plasticizer system of PE and EC was higher than that of pure PC. Ion conductivity of PGEs with a film thickness of $20{\mu}m$ was higher, but electrochemical characteristics of unit cells were higher for a $50{\mu}m$ membrane thickness. Also, the unit cell has shown the highest capacitance of 31.41 F/g and more stable electrochemical performance when PGE and electrode were hot pressed. Consequently, the optimum composition ratio of PGE for EDLCs was 23 : 66 : 11 wt% such as P(VdF-co-HFP) : PVP = 20 : 3 wt% and PC : EC = 44 : 22 wt%. In this case, $3.17{\times}10^{-3}S/cm$ of ion conductivity was achieved at the $50{\mu}m$ thickness of PGE for EDLCs. And the electrochemical characteristics of unit cells were $2.69{\Omega}$ of DC-ESR, 28 F/g of specific capacitance, and 100% of coulombic efficiency.