• 제목/요약/키워드: physicochemical parameters

검색결과 323건 처리시간 0.024초

노르후록사신-금속이온 착물의 물리화학적 성질 및 항균력 (Physiochemical Properties and Antibacterial Activities of Metal Complexes of Norfloxacin)

  • 박원봉;김경아;이명환;이동선;노동윤
    • 약학회지
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    • 제36권6호
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    • pp.577-581
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    • 1992
  • Norfloxacin complexes of $Fe^{2+}$, $Cu^{2+}$ and $Al^{3+}$ have been prepared as solids. The stoichiometry of the complexes has been established. IR investigation indicates the metal-ligating sites in norfloxacin. The bioactivities of complexes all lower than that of norfloxacin. The solubilities and partition coefficients have been measured as a function of temperature. The data are used to evaluate the thermodynamic parameters ${\Delta}G$, ${\Delta}H$, ${\Delta}S$ for the solute transfer process and compared with the parent quinolone, norfloxacin. The existence of such complexes is discussed in the light of quinolone mode-of-action theories.

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열쇼크방식 살균에 의한 무균 취반의 미생물학적 품질관리 (Microbiological Quality Control of Cooked Rice by Aseptic Process Using Heat Shock Treatment)

  • 홍정화;허성호;신명호
    • 한국식품영양과학회지
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    • 제27권6호
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    • pp.1094-1099
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    • 1998
  • Newly introduced aseptic process for cooked rice was optimized by evaluating the process parameters. The optimal conditions were as follows: ratio of washing water to rice, 3:1 by weight; steeping at 20oC for 20min; heat shock at 140oC for 7sec with 8 repetitions; addition of 0.2% glucono lactone solution; cooking at 103oC for 30min. The final products were incubated at 37oC and 50oC for 8 weeks and no spoilage was occurred at both temperatures. Furthermore, any significant losses of sensory and physicochemical qualities were not observed.

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Development of analytical method for potential diesel oxygenate using SPME technique combinded with GC-FID

  • 이규현;이시진;장순웅
    • 한국지하수토양환경학회:학술대회논문집
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    • 한국지하수토양환경학회 2004년도 총회 및 춘계학술발표회
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    • pp.354-357
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    • 2004
  • The addition of oxygenates to diesel fuel can significantly reduce particulate emissions. Dibutyl maleate (DBM) and tripropylene glycol methyl ether (TGME) have been identified as possible additives based on their physicochemical characteristics and performance in engine test. However, their potential environmental impacts are unknown. therefore, practical considerations in the selection of an oxygenate additives should include cost, availability, compatibility with engines and fuel, and, particularly, its overall environmental impact. This study was investigated to determine optimal condition for the analysis of potential diesel oxygenates using SPME technique with GC-FID. Four fibers were compared and CAR/PDMS fiber was found to be the most sensitive when used direct-sampling. An absorption time of 30min and a desorption time of 5min provided to be the most sensitivity. The effects of experimental parameters such as the addition of salts, agitation, absorption time, compositon on the analysis were investigated. Analytical parameter such as linearity was also evaluated.

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THE RELATIONSHIP OF INTESTINAL ABSORPTION CLEARANCE AND PARTITION COEFFICIENT OF NINE BETA-BLOCKERS IN RATS

  • Cho, Hea-Young;Lee, Suk;Kang, Hyun-Ah;Lee, Yong-Bok
    • 대한약학회:학술대회논문집
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    • 대한약학회 2002년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2
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    • pp.411.3-412
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    • 2002
  • On the basis of recognizing that physicochemical properties (lipophilic/hydrophilic), intestinal absorption clearance and pharmacokinetic characteristics of drug are the fundamental parameters controlling the rate and the extent of drug absorption, the biopharmaceutics classification system for the correlation between drug lipid- solubility and intestinal absorption clearance is proposed. (omitted)

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Sulfonated PEEK Ion Exchange Membranes for Direct Methanol Fuel Cell Applications

  • Moon, Go-Young;Rhim, Ji-Won
    • Macromolecular Research
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    • 제15권4호
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    • pp.379-384
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    • 2007
  • Sulfonation of polyetheretherketones (PEEK) was carried out in order to fabricate commercial perfluorosulfonic acid membrane alternatives, which were characterized in terms of their ion exchange capacity, ionic conductivity, water swelling, methanol crossover and electrochemical performance in their direct application as a methanol fuel cell. A high ion exchange capacity, 1.88, was achieved with a sulfonation reaction time of 8 h, with a significantly low methanol crossover low compared to that of Nafion. However, the morphological stability was found to deteriorate for membranes with sulfonation reaction times exceeding 8 h. Electrochemical cell tests suggested that the fabrication parameters of the membrane electrode assembly based on the sulfonated PEEK membranes should be optimized with respect to the physicochemical properties of the newly prepared membranes.

Biochemical Studies of an Endoglucanase from Marine Rotifer, Brachionus plicatilis

  • Chun Chang Zoon;Park Heum Gi;Hur Sung Bum;Kim Young Tae
    • 한국양식학회지
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    • 제9권4호
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    • pp.453-459
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    • 1996
  • Cellulase was purified from marine rotifer, Brachionus plicatilis, to homogeneity by using chromatographic methods. Purified enzyme is an endo-${\beta}$-1,4 glucanase and shows a strong hydrolytic activity against carboxymethyl (CM) -cellulose. The physicochemical parameters of enzyme activity were determined. The molecular weight of the purified protein was approximately 62 kDa as determined by SDS-polyacrylamide gel electrophoresis. The enzymatic capability to digest cellulose of Chlorella cell wall was compared with that of other well known cellulases from Thermomonospora fusca. Experiments involving Chlorella digestion indicated that CM-cellulase from marine rotifer, Brachionus plicatilis, could digest Chlorella very efficiently while cellulase purified from Thermomonospora fusca did not. From the result here, we propose that the cellulolytic system from marine rotifer is responsible for the hydrolysis of cellulosic wall of Chlorella, probing that rotifer digests Chlorella as a major live food.

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튀김온도에서 가열한 우지 중의 콜레스테롤 산화 생성물 (Oxidation Products of Cholesterol in Tallow Heated at Deep-Fat Frying Temperatures)

  • 신효선;양주흥;김종승
    • 한국식품위생안전성학회지
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    • 제9권4호
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    • pp.199-203
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    • 1994
  • The oxidation of cholesterol in tallow heated at three frying temperatures, 130, 150 and 18$0^{\circ}C$ was studied by assaying cholesterol oxidation products(COP)by GC-MS. The correlation between levels of COP and changes of physicochemical parameters (peroxide value, polymer, polar components and dielectric constant) in tallow heated were studied. As temperature increased, the amount of cholesterol was decreased proportionally with heating time. However, the levels of COP did not increase considerably with increased frying temperature. The rate of cholesterol disappearance was the greatest at 18$0^{\circ}C$ and the smallest at 13$0^{\circ}C$. Larger amounts of COP formed were found at 15$0^{\circ}C$ than at 18$0^{\circ}C$. The levels of COP formed in tallow heated showed highly correlation with(r=0.94, n=30, p<0.01) polymer, polar components and dielectric constant, respectively.

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대두 Cheese의 제조와 그의 일반 성분 및 수응도에 관한 연구 (Preparation of various soy cheese and their physicochemical and sensory characteristics)

  • 양경순;윤선
    • 한국식품조리과학회지
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    • 제3권2호
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    • pp.75-80
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    • 1987
  • For the manufacture of soybean cheese, curds were made from soy milk using either lactic starter or CaCl$_2$and ripened for 3 weeks. When papain was added during ripening, the amout of soluble protein increased. The yields of 3 soybean cheese were 76~88%, indicating that considerable loss of soy protein did not occur during the processing. During the period of ripening the change of moisture content was about 1 n. Total acidity of 3 soy cheese increased, demonstrating the production of lactic acid through lactic fermentation. Texture determined by Instron showed that 3 soy cheese had their own characteristic texture profile curve and that the cheese without papain treatment received the highest textural parameters. 3 manufactured soy cheese received 3-4 (good-very good) sensory scores in appearance, flavor and texture. General acceptibility of 3 cheese were evaluated as desirable or very desirable.

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구조-활성 상관관계. 5-Lipoxygenase의 저해제인 Catechol류에 관한 이론적 연구 (Structure-Activity Relationship. A Theoretical Study of Catechol Derivatives as 5-Lipoxygenase Inhibitor)

  • 박성식;김상윤;정덕영;여수동
    • 대한화학회지
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    • 제39권9호
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    • pp.741-748
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    • 1995
  • 5-Lipoxyhenase의 저해제인 catechol류에 대한 구조-활성관계를 검토하였다. Catechol 유사체의 활성자리와 수용체가 작용하는 약물-수용체 상호작용 모델을 설정하여 가하학적, 전기적 파라미터를 구하여 생리활성과의 상관관계를 분석, 다중회귀분석을 실시하였다.

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Tetramethylpyrazine Protects Oxidative Stability and Gelation Property of Rabbit Myofibrillar Proteins

  • Wang, Jianping;Liu, Ning;Zhang, Feike
    • 한국축산식품학회지
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    • 제39권4호
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    • pp.623-631
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    • 2019
  • Tetramethylpyrazine (TMP), an alkaloid rich in Ligusticum wallichii and fermented products, possesses multiple pharmacological activities in antioxidant, antiinflammatory, and antibacterial. This study aimed to investigate the effect of TMP (15 mg/L) on the physicochemical and gelation properties of rabbit myofibrillar proteins (MPs) with/without oxidative stress. Results showed that compared to the control, oxidative stress to MPs decreased free thiol content, gel yield, whiteness, water-holding capacity, bounder water, immobilized water, and endogenous tryptophan fluorescence intensity, but increased surface hydrophobicity, dityrosine content, and free water content (p<0.01). Without oxidative stress, MPs treated with TMP increased free thiol content, whiteness, and bound water, but decreased dityrosine content and free water (p<0.05). Under oxidative conditions, all parameters were conversely affected by TMP (p<0.01). The results suggest that TMP can be an antioxidant to decrease the concern on oxidative deterioration during meat processing and storage by improving the oxidative stability, water retention, and gel forming property of rabbit MPs.