• Natural Product Sciences
• /
• 제14권3호
• /
• pp.161-166
• /
• 2008

A mixture of sixteen cerebrosides, which comprised four cerebroside molecular species (PL-1 ${\sim}$ PL-4) was separated from the roots of Paeonia lactiflora. The structures of cerebrosides were characterized as $1-O-{\beta}$-D-glucopyranosides of phytosphingosines, which comprised a common long-chain base, (2S,3S,4R,8E/Z)-2-amino-8-octadecene-1,3,4-triol with eight fatty acids or 2-hydroxy fatty acids of varying chain lengths ($C_{16}$, $C_{18}$, $C_{20-26}$) linked to the amino group. Aralia cerebroside and its 8Z isomer (PL-1), $1-O-{\beta}$-D-glucopyranosyl-(2S,3S, 4R,8E/Z)-2-[(2'R)-2'-hydroxytetracosanoylamino]-8-octadecene-1,3,4-triol (PL-2), $1-O-{\beta}$-D-glucopyranosyl-(2S,3S,4R, 8E/Z)-2-[(2'R)-2'-hydroxydocosanoylamino]-8-octadecene-1,3,4-triol (PL-3), and $1-O-{\beta}$-D-glucopyranosyl-(2S,3S,4R, 8E/Z)-2-[(2'R)-2'-hydroxytricosanoylamino]-8-octadecene-1,3,4-triol (PL-4) were identified as major components of these cerebroside molecular species. All the major cerebrosides were shown to be a mixture of geometrical isomers (8E and 8Z) of phytosphingosine-type glucocerebrosides possessing 2R-hydroxy fatty acids. In addition, three ${\beta}-sitosterol$ derivatives and adenosine were also separated. The structures of these isolates have been determined on the basis of chemical and spectroscopic evidence.

• 공업화학
• /
• 제10권4호
• /
• pp.592-598
• /
• 1999

건축용 외장재로 사용되는 인조석은 혼합수, 시멘트, 석분, 경량골재를 사용하여 만들어지는데, 본 연구에서는 인조석의 제조단가를 낮추고 물성을 향상시키기 위하여 ${\beta}$-NSF계 계면활성제와 빈졸계 계면활성제를 사용하였다. 본 연구를 통해 ${\beta}$-NSF계와 빈졸계 계면활성제의 최적 배합비가 1.0 wt %와 0.1 wt % 됨을 도출하였고, 새로 개발된 인조석은 기존의 인조석에 비하여 물성이 약 20 wt 증가하고, 동결융해 저항성이 300% 증가하였다. 그러나, 제조가격은 기존의 제품에 비해 30% 이상 감소된다.

• Journal of Radiation Protection and Research
• /
• 제26권4호
• /
• pp.375-384
• /
• 2001

베타선 스펙트럼의 최대 에너지가 확실하게 구별되는 2개의 핵종만을 포함하는 혼합시료의 경우에는 최대 에너지가 다르다는 점을 이용하여 손쉽게 각 핵종의 방사능 값을 측정할 수 있다. 그러나 3개 이상의 베타 방출 핵종이 포함된 혼합물에 대해서는 각 핵종의 스펙트럼이 서로 겹치기 때문에 이러한 방법으로 구해진 방사능 값은 신뢰도가 떨어지게 된다. 따라서, 본 연구에서는 최소자승법을 이용하여 혼합물의 중첩된 베타선 스펙트럼을 각각 분리 정량분석 할 수 있는 방법을 제시하였다. 또한, 실제로 4개의 베타 방출 핵종($^3H,\;^{14}C,\;^{36}Cl\;^{90}Sr$)이 혼합된 시료를 조제하여 본 분석법을 검증한 결과 참고치(Reference value)와 분석치가 7% 이내에서 잘 일치함을 보였다.

• 생약학회지
• /
• 제19권3호
• /
• pp.170-173
• /
• 1988

(-)-Epicatechin, $mp\;234{\sim}6^{\circ}$, was isolated from the fresh roots of Rubus parvifolius together with a sterol mixture, which was found to be a mixture of ${\beta}-sitosterol\;(major)$, stigmasterol and campesterol.

• 한국동물위생학회지
• /
• 제30권4호
• /
• pp.505-510
• /
• 2007

This study was conducted to detect ${\beta}$-lactam antibiotic-resistant genes in the 400 E coli isolates from porcine fecal samples in Korea by a DNA chip. The DNA chip contains the specific probe DNAs of the ${\beta}$-lactam antibiotic-resistant genes that had been labeled with a mixture of primer set designed to amplify specific genes (PSE, OXA, FOX, MEN, CMY, TEM, SHV, OXY and AmpC) using a multiplex polymerase chain reaction (PCR). Of 400 isolates 339 contained at least one ${\beta}$-lactamases gene. Resistance to ${\beta}$-lactamases was mediated mainly by AmpC (n = 339, 100%), and followed by TEM (n = 200, 59.0%), CMY (n = 101, 29.8%), PSE (n = 30, 8.9%) and both OXA and SHV genes (n = 20, 5.9%), while the FOX, MEN and OXY genes were not detected. The other sixty-one did not contain any ${\beta}$-lactamase genes even though they were resistant to antimicrobial drugs. In conclusion, the DNA chip system can be used as a rapid and reliable method for detecting of ${\beta}$-lactamases genes, which will help veterinarians select the antibiotics for monitoring and treating of animal diseases.

• 한국세라믹학회지
• /
• 제25권5호
• /
• pp.473-478
• /
• 1988

In order to obtain the high purity $\beta$-SiC powder that possesses the excellent sinterability and is close to the spherical shape, the carbon black was mixed into the composition of Si(OC2H5)4-H2O-NH3-C2H5OH which the monodispersed spherical fine particles is formed the hydrolysis of Ethylsilicate and the mixture was carbonized under an argon atmosphere. Particle shpae, size and the yield of $\beta$-SiC powder were investigated according to the molar ratio of carbon/alkoxide and variations of reaction temperature and reaction time. The results of this study are as follow ; 1) The yield of $\beta$-SiC gained from the reaction for one hour at 150$0^{\circ}C$ almost got near 100% and the particle size of $\beta$-SiC from the reaction for 15 hrs at 150$0^{\circ}C$ was 0.2${\mu}{\textrm}{m}$ on the average and close to the spherical shape agglomerate state. 2) When the molar ratio carbon/alkoxide is over 3.1 and the reaction occurs at 145$0^{\circ}C$ for 5hrs, the carbon content has not an effect on the kind of crystal of product.

• 한국정밀공학회지
• /
• 제31권9호
• /
• pp.791-797
• /
• 2014

Abstract Scaffold used as a carrier of the cell has been actively conducted using plenty of technology in tissue engineering. ${\beta}$-tricalcium phosphate (${\beta}$-TCP) material has shown good biocompatibility and osteoconductive ability when it was implanted as a bone graft substitute in osseous defect in human and animal studies for bone regeneration. In this study, we fabricated the blended polycaprolactone (PCL) and ${\beta}$-TCP scaffold by the polymer deposition system (PDS). The PCL/${\beta}$-TCP scaffold was fabricated at a temperature of $110^{\circ}C$, pressure of 650 kPa, and scan velocity of 100 mm/sec. The Overall geometry and size of the scaffold were fixed circle type with a diameter of 10 mm and a height of 4 mm. PCL/${\beta}$-TCP scaffold was observed by scanning electron microscopy. Cell attachment and proliferation of the scaffold containing 30 wt% ${\beta}$-TCP was superior to those containing 10 wt% and 20 wt% ${\beta}$-TCP.

• 한국수의병리학회:학술대회논문집
• /
• 한국수의병리학회 2003년도 추계학술대회초록집
• /
• pp.33-33
• /
• 2003

There prevalence of $\beta$-lactamases bacteria in animals has been increased since 1990s [1]. The resistance in E coli which is mediated by $\beta$-lactamases hydrolyze the $\beta$-lactam ring eventually inactivate the antibiotics [2]. Generally, $\beta$-lactamases can be classified into four main groups and eight subgroups according to their functional and structural characteristics [3]. The detection of $\beta$-lactam antibiotic-resistant bacteria by DNA chip has been described [4]. The chip has a specific probe DNAs that contained the $\beta$-lactam antibiotic-resistant genes which was labeled by multiplex PCR reaction with a mixture of primer sets that were designed to amplify specific gene. Here we report the susceptibility of enteropathogenic E. coli isolated from pigs in Korea using the DNA chip in detecting $\beta$-lactam antibiotic-resistant genes. (omitted)

• 폴리머
• /
• 제38권3호
• /
• pp.338-350
• /
• 2014

Cellulose acetate (CA) fiber mats containing inclusion complexes of asiaticoside (AC) in 2-hydroxypropyl-${\beta}$-cyclodextrin ($HP{\beta}CD$) for potential usage as wound dressings were developed. The AC/$HP{\beta}CD$ complex-loaded CA fibers at various $HP{\beta}CD$ to AC molar ratios of 0.5, 1, and 2 were prepared in 90:10 v/v mixture of 80% (v/v) acetic acid and N,N-dimethylacetamide (DMAc) via electrospinning. The maximum released amounts of AC depended on the $HP{\beta}CD$ content and were much greater than those released from the AC-loaded CA fiber mat. In the in vitro study, indirect cytotoxic evaluation with human dermal fibroblasts (HDFa) showed that these materials released no substances in the levels that were harmful to the cells and the cells appeared to attach and proliferate well on these substrates. However, only the CA fiber mats containing AC/$HP{\beta}CD$ complexes at the $HP{\beta}CD$ to AC molar ratio of 0.5 was effective in upregulating the production of collagen of the cultured cells.

• 한국세라믹학회지
• /
• 제43권10호
• /
• pp.595-600
• /
• 2006

The preparation of $\beta$-SiAlON powder by SHS in the system of $Si-Al-SiO_2-NH_4F(\beta-Si_3N_4)$ was investigated in this study. In the preparation of SiAlON powder, the effect of gas pressure, compositions such as Si, $NH_4F$, \beta-Si_3N_4$ and additive in mixture on the reactivity were investigated. At 50 atm of the initial inert gas pressure in reactor, the optimum composition for the preparation of pure $\beta$-SiAlON was $3Si+Al+2SiO_2+NH_4F$. The $\beta$-SiAlON powder synthesized in this condition was a single phase $\beta$-SiAlON with a rod like morphology.