• Asian-Australasian Journal of Animal Sciences
• /
• 제14권3호
• /
• pp.358-364
• /
• 2001

The physiochemical properties and interactions between porcine blood and waxy rice were determined. Addition of calcium chloride (0.15%) improved acceptability of blood cake and increased the gelatinization degree of waxy rice. The water-holding capacity of porcine blood gel (blood/water=60/40, v/v), extent of absorption and gelatinization of waxy rice, and scanning electron microscopy showed that blood protein matrix and waxy rice are competitors for holding water in the cooking procedure. Non-haem iron content increased linearly (R=0.95) when heating temperature rose. The presence of blood proteins caused increasing of peak temperature (Tp) of gelatinization in differential scanning calorimetric thermal gram, The microstnlcture of plasma proteins and haemoglobin appeared continuous changes, and interacted with surface of waxy rice flour in terms of network and mosaic form, respectively. The electrophoretic patterns revealed an interaction between plasma proteins and waxy rice glutelin and haemoglobin when heated could be found at temperatures above $60^{\circ}C$.

• 한국응용약물학회:학술대회논문집
• /
• 한국응용약물학회 1996년도 춘계학술대회
• /
• pp.286-286
• /
• 1996

In order to elucidate the mechanism of action of transdermal absorption-enhancing compounds, i.e., pyrrolidone derivatives (2-pyrrolidone, 1-methyl-2-pyrrolidone, 1-ethyl-2-pyrrolidone, 1,5-dimethyl-pyrrolidone and 5-methyl-2-pyrrolidone), multilamellar liposome was prepared from the simulated stratum corneum lipid and employed as a model system for the barrier function of the stratum corneum. The liposomal membrane of the stratum corneum lipid liposome (SCLL) behaves as an osmometer and has an excellent barrier function. In addition, its phase transition temperatures are similar to those of human stratum corneum intercellular lipid region. Therefore, SCLL seems to be a useful skin model. To estimate the barrier function of SCLL, the osmotic behavior of SCLL was measured in the presence of pyrrolidone derivatives and the effect on the phase transition temperature of SCLL was also investigated using differential calorimetry. Above a certain concentration (MLAC), enhances perturb the barrier function of the liposome. The relationship between MLACs and the partition coefficient of the pyrrolidone derivatives was observed; the greater the partition coefficients, the smaller the MLAC. This suggests that the more hydrophobic enhancers penetrate into the lipid layer more easily and reduce the barrier function of membrane more effectively. The results of differential scanning thermograms of the SCLL suggest that the pyrrolidone derivatives had incorporated into the lipid layer in the liposome and increased the fluidity of the lipid layer in the liposome. Such activity might have some correlation with the transdermal absorption-enhancing activity these compounds.

• Journal of the Korean Wood Science and Technology
• /
• 제34권5호
• /
• pp.59-66
• /
• 2006

The thermal properties of wood flour, Hwangto, and maleated polyethylene (MAPE) reinforced HDPE composites were investigated in this study. The thermal behavior of reinforced wood polymer composites was characterized by means of thermogravimetric (TGA) and differential scanning calorimetric (DSC) analyses. Hwangto and MAPE were used as an inorganic filler and a coupling agent, respectively. According to TGA analysis, the increase of wood flour level increased the thermal degradation of composites in the early stage, but decreased in the late stage. On the other hand, Hwangto reinforced composites showed the higher thermal stability than virgin HDPE, from the determination of differential peak temperature ($DT_p$). Decomposition temperature of wood flour and/or Hwangto reinforced composites increased with increase of heating rate. From DSC analysis, melting temperature of reinforced composites little bit increased with the addition of wood flour or Hwangto. As the loading of wood flour or Hwangto to HDPE increased, overall enthalpy decreased. It showed that wood flour and Hwangto absorbed more heat energy for melting the reinforced composites. Hwangto reinforced composites required more heat energy than wood flour reinforced composites and virgin HDPE. Coupling agent gave no significant effect on the thermal properties of composites. Thermal analyses indicate that composites with Hwangto are more thermally stable than those without Hwangto.

• 한국잠사곤충학회지
• /
• 제49권2호
• /
• pp.77-80
• /
• 2007

실크단백질을 이용한 나노화 소재개발을 위한 기초연구의 일환으로 실크 피브로인과 PVP를 반응시켜 제조한 견단백질/PVP의 열 특성을 살펴보기 위하여 시차열분석 및 열중량분석을 행하였다. 1. PVP의 유리전이온도는 $175^{\circ}C$ 부근에서 관찰되었으며 실크 단백질과 반응에 의하여 영향을 받지 않았으나 견단백질/PVP는 $220^{\circ}C$ 부근에서 미지의 발열피크를 나타내었다. 2. 열중량 분석 결과 PVP의 함량이 증가함에 따라 실크 단백질에 기인한 열분해시작온도가 상대적으로 증가하는 것으로 관찰되었다.

• Archives of Pharmacal Research
• /
• 제23권4호
• /
• pp.381-384
• /
• 2000

It is well recognized that physicochemical properties of drugs are affected by the type of polymorphic crystalline form of drugs. Clarithromycin is known to exist in at least three polymorphic crystalline forms. Since conventional means to obtain the most thermodynamically stable form (Form II) for the antibiotics is known to be associated with a low purity of the stable form, we developed a novel method to improve the purity of the crystalline form by a modification of the preparation process. The new method involved a simple recrystallization of clarithromycin in solvents having 5-12 carbon atoms (e.g., hexane and heptane) or ethers with 4-10 carbon atoms (e.g., isopropyl ether) and, thus, less likely to be associated with the problem in purity of resulting crystal. Differential scanning calorimetry and powder X-ray diffraction were used to compare the crystalline form of the resultant powder with Form IIcrystal prepared by the conventional method. The crystal prepared by the new method was identical to Form IIcrystal of the conventional method as evidenced by the lack of the exothermic peak near 11$0^{\circ}C$ in differential calorimetry scan, indicating that Form IIcrystal could be readily prepared by the new process. Therefore, these data indicated that the improvement in the purity of the Form IIcrystal for clarithromycin as well as a significant cost reduction is likely by the novel method.

• Bulletin of the Korean Chemical Society
• /
• 제33권5호
• /
• pp.1647-1652
• /
• 2012

With the objective to design and synthesis of Schiff's base symmetrical liquid crystal dimmers and to study the effect of molecular structure variation ($o-ortho$, $m-meta$, $p-para$) and change in alkoxy terminal chain length on mesomorphic properties of liquid crystals, We have synthesized Schiff base dimers from dialdehyde derivative containing 2-hydroxy-1,3-dioxypropylene as short spacer with aniline derivatives having different lengths of terminal alkoxy chains ($n$ = 5, 7, 9). The chemical structure of the final products was characterized by proton nuclear magnetic resonance ($^1H$ NMR) spectroscopy and fourier transform infrared (FT-IR) spectroscopy. The mesomorphic properties and optical textures of the resultant dimers were characterized by differential scanning calorimetry (DSC) and polarized optical microscopy (POM). The existence of smectic A phase transition was confirmed by the observation of batonnets and fan shaped textures in optical microscopy when compound were heated from crystalline phase. All of the dimers of this series, with the exception of $\mathbf{2S_5}$ -ortho, -meta, -para, were thermotropic liquid crystal. The compound $\mathbf{2S_9}$ -meta was monotropic, while the rest were enantiotropic. It was found that the change in terminal alkoxy chain length has pronounced effect on the mesomorphic properties. The temperature range of smectic A phase window widens with increasing alkoxy chain length.

• Journal of the Korean Wood Science and Technology
• /
• 제40권2호
• /
• pp.110-122
• /
• 2012

This study investigated the effects of layered clay on the thermal curing behavior and tensile properties of resole phenol-formaldehyde (PF) resin/clay/cellulose nanocomposites. The thermal curing behavior of the nanocomposite was characterized using conventional differential scanning calorimetry (DSC) and temperature modulated (TMDSC). The addition of clay was found to accelerate resin curing, as measured by peak temperature ($T_p$) and heat of reaction (${\Delta}H$) of the nanocomposite’ curing reaction increasing clay addition decreased $T_p$ with a minimum at 3~5% clay. However, the reversing heat flow and heat capacity showed that the clay addition up to 3% delayed the vitrification process of the resole PF resin in the nanocomposite, indicating an inhibition effect of the clay on curing in the later stages of the reaction. Three different methods were employed to determineactivation energies for the curing reaction of the nanocomposite. Both the Ozawa and Kissinger methods showed the lowest activation energy (E) at 3% clay content. Using the isoconversional method, the activation energy ($E_{\alpha}$) as a function of the degree of conversion was measured and showed that as the degree of cure increased, the $E_{\alpha}$ showed a gradual decrease, and gave the lowest value at 3% nanoclay. The addition of clay improved the tensile strengths of the nanocomposites, although a slight decrease in the elongation at break was observed as the clay content increased. These results demonstrated that the addition of clay to resole PF resins accelerate the curing behavior of the nanocomposites with an optimum level of 3% clay based on the balance between the cure kinetics and tensile properties.

• 대한화장품학회지
• /
• 제38권3호
• /
• pp.197-200
• /
• 2012

보습제 베이스를 립스틱에 사용하여 보습효과가 우수한 제품개발에 응용하고자 DSC에 의한 결합수형성능, 수분보유능을 고찰하였다. 보습제 베이스를 배제한 견본에서 결합수 형성능은 5.12 %임을 알았다. 보습제 베이스함량에 따른 결합수형성능을 측정한 결과 보습제 베이스 함량이 증가함에 따라 결합수 형성능이 비례적으로 증가함을 DSC측정결과 알았다. 한편 DSC측정결과와 in vitro 수분보유능 측정법을 비교 실험한 결과 유사한 경향을 나타냄을 알 수 있었다. 따라서 DSC에 의한 결합수 형성능 측정법은 앞으로 립스틱 제품의 보습효과를 예측 하는데 유용한 방법으로 생각되었다.

• 한국전기전자재료학회논문지
• /
• 제19권7호
• /
• pp.650-654
• /
• 2006

[ $LiNi_{0.4}Mn_{0.3}Co_{0.3}O_2$ ] cathode material was synthesized by a mixed hydroxide method. Structural characterization was carried out using X-ray diffraction studies. Electrochemical studies were performed by assembling 2032 coin cells with lithium metal as an anode. DSC (Differential scanning calorimetry) data showed that exothermic reactions of $LiNi_{0.4}Mn_{0.3}Co_{0.3}O_2$ charged to 4.3 V versus Li started at high temperatures$(280\sim390^{\circ}C)$. The cell of $LiNi_{0.4}Mn_{0.3}Co_{0.3}O_2$ mixed cathode delivered a discharge capacity of 150 mAh/g at a 0.2 C rate. The capacity of the cell decreased with the current rate and a useful capacity of 134 mAh/g was obtained at a 2 C rate. The reversible capacity after 100th cycles was 126 mAh/g when a cell was cycled at a current rate of 0.5 C in $2.8\sim4.3V$.

• 공업화학
• /
• 제24권2호
• /
• pp.144-147
• /
• 2013

Sweating은 오일 중에 수종의 안료를 분산시키고 이들을 왁스로 고화시킨 계의 표면에 출현하는 특이한 현상으로 립스틱이나 커버메이크업 같은 고형 제품에 흔히 나타나며 원인은 불균형한 처방에 기인한다. 그동안 화장품 분야에서 Sweating 현상을 개선하기 위하여 많은 연구가 진행되어 왔다. DSC는 주로 일정 조건 하에서 온도에 따른 시료의 열적 특성의 변화를 측정하는 분석 방법으로 이 변화를 온도 또는 시간의 함수로 기록하는 기기를 말한다. 오일/왁스구조의 열적 특성(thermal property)을 파악하기 위하여 DSC를 이용하였으며, 이러한 열적 특성과 Sweating 현상이 어떠한 상관관계가 있는지 파악하였다. 오일/왁스 제형 중 온도 변화에 따른 구조 변화가 적은 열적 특성을 나타내고 사용감과 제형 안정성을 갖는 최적융점의 오일/왁스 제형을 연구하였다. 또한, 다양한 온도 범위에서 오일/왁스 제형의 Sweating 현상을 관찰하였으며 그 결과 온도 변화에 따른 구조 변화가 적은 오일/왁스 제형이 Sweating 현상도 최소화하는 조합임을 관찰하였다.