Bone remodeling is a process controlled by the action of two major bone cells; the bone forming osteoblast and the bone resorbing osteoclast. In the process of osteoclastogenesis, stromal cells and osteoblast produce RANKL, OPG, and M-CSF, which in turn regulate the osteoclastogenesis. During the bone resorption by activated osteoclasts, extracellular Ca²+/PO₄²- concentration and degraded organic materials goes up, providing the hypertonic microenvironment. In this study, we tested the effects of hypertonicity due to the degraded organic materials on osteoclastogenesis in co-culture system. It was examined the cellular response of osteoblastic cell in terms of osteoclastogenesis by applying the sucrose, and mannitol, as a substitute of degraded organic materials to co-culture system. Apart from the sucrose, mannitol, and NaCl was tested to be compared to the effect of organic osmotic particles. The addition of sucrose and mannitol (25, 50, 100, 150, or 200 mM) to co-culture medium inhibited the number of tartrate-resistant acid phosphatase (TRAP) positive multinucleated cells induced by 10 nM (). However, NaCl did exert harmful effect upon the cells in this co-culture system, which is attributed to DNA damage in high concentration of NaCl. To further investigate the mechanism by which hypertonicity inhibits -induced osteoclastogenesis, the mRNA expressions of receptor activator of nuclear factor (NF)-kB ligand (RANKL) and osteoprotegerin (OPG) were monitored by RT-PCR. In the presence of sucrose (50 mM), RANKL mRNA expression was decreased in a dose-dependent manner, while the change in OPG and M-CSF mRNA were not occurred in significantly. The RANKL mRNA expression was inhibited for 48 hours in the presence of sucrose (50 mM), but such a decrement recovered after 72 hours. However, there were no considerable changes in the expression of OPG and M-CSF mRNA. Conclusively, these findings strongly suggest that hypertonic stress down-regulates -induced osteoclastogenesis via RANKL signal pathway in osteoblastic cell, and may playa pivotal role as a regulator that modulates osteoclastogenesis.

The elderly suffer from an impaired immune function being obvious in a higher susceptibility to infections. Although the inflammatory cells are the major immunomodulatory cells, fibroblasts also secrete a variety of inflammatory cytokines and chemokines. Therefore periodontal tissue aging might playa role in development and progress of periodontitis. In this study, we investigated the effect of in vitro periodontal ligament cellular aging on the inflammatory cytokines, chemokines, and matrix metalloprotease(MMP)-2 expression induced by lipopolysaccharide(LPS) treatment. Three different cell populations were used; passages 4-5, 14-15, and 24-25 (at passage 27, more than 90% cells were replicative senescent). LPS increased the expression of interleukin(IL)-1β, IL-6, and tumor necrosis factor-α, IL-8, RANTES, and MMP-2. However, the order of induction folds were passages 14-15 > 4-5 > 24-25. While the expression level of Toll-like receptor(TLR) 4 decreased according to the increase in passage number, the level of TLR2 was highest at passages 14-15 and then decreased at passages 24-25. While the spontaneous expression of IL-8 decreased according to the increase in passage number, that of RANTES and proMMP-2 increased according to the increase in passage number. These results suggest that the aging of periodontal ligament fibroblasts differentially affect the role as immunomodulatory cells in response to periodontopathic bacteria and therefore might be another risk factor of periodontitis progression.

We analyzed the high resolution H,6 line spectra of CH Cygni obtained at the Bohyunsan Astronomical Observatory (BOAO) on April 2004. The temporal changes in the Hβ line profiles are reported. We obtained the equivalent widths of the Gaussian components. Using this we estimated the length of the gaseous nebula which emits the Hβ line and the mass loss rate from the star.

원형질체 융합에 의한 화합성 및 불화합성 종간 체세포잡종을 얻었다. 화합성 종간인 Pleurotus ostreatus 와 P. florida 의 융합체는 이질핵체 (heterokaryon) 를 형성하였고, 불화합성 종간인 P. cornucopiae + P. florida , P. ostreatus + Ganoderma applanatum, P. florida + Ganoderma lucidum, 그리고 P. ostreatus + Flammulina velutipes 는 합핵체(synkaryon) 를 형성하였다. 이질이핵체는 동일한 양상의 자실체를 형성하는데 비해 합핵체는 유사분열상의 꺽쇠연결체 형성, 한쪽 친과 유사한 자실체 형성, 비정상적 유전형질 분리 및 유전자재조합 현상을 나타내었다. 화합성 및 불화합성 계통간 융합체의 RAPD 분석결과 화합성 종간 융합체는 동일한 DNA 패턴을 나타내었고, 불화합성 종간 융합체는 한쪽 친과 유사한 DNA 양상이면서 비양친 DNA 밴드도 형성하였다. 합핵체의 패턴은 microgenome insertion type 과 macrogenome insertion type 으로 구분되었다. 합핵체의 자실체 발생은 융합 모균주 양친의 자가임성에 의존하는데 이는 느타리의 동형핵체 자가임성과 유사한 양상이었고, 교배형 전환과 관련이 있는 것으로 사료된다. 여기서는 이러한 관점에서 논할 것이다.

Carbon molecular sieve (CMS) membranes were prepared by pyrolysis of polyimides having carboxylic acid groups and applied to the hydrogen separation. The polymeric membranes having carboxylic acid groups showed different steric properties as compared with polymeric membranes having other side groups (-CH3 and -CF3) because of the hydrogen bond between the carboxylic acid groups. However, the microporous CMS membranes were significantly affected by the decomposable side groups evidenced from the wide angle X-rat diffraction, nitrogen adsorption isotherms, and single gas permeation measurement. Furthermore, the gas separation properties of the CMS membranes were essentially affected by the pyrolysis temperature. As a result, the CMS membranes Prepared by Pyrolysis of polyimide containing carboxylic acid froups at 700℃ showed the H2 permeability of 3,809 Baller [1×10-10 H cm(STP)cm/cm2.s.cmHg], H2/N2, selectivity of 46 and H2/CH4 selectivity of 130 while the CMS membranes derived from polyimide showed the H2 permeability of 3,272 Barrer, H2/N2 selectivity of 136 and H2/CH4 selectivity of 177.

The rapid growth of the food packaging field is powered by the ever growing health conscious consumers and demand for fresher and higher quality foods. Active packaging technologies provide solutions for extending products shelf life with specially altered packaging systems. Among the several shelf life enhancer systems, active packaging system for preventing oxidation is discussed in this paper. Oxidation is generally regarded as the main factor in the development of rancidity of fats and oils. The oxidative processes result in the food becoming unacceptable for consumers. Such oxidation is inhibited by exclusion of oxygen and by the presence of antioxidants. First of all, oxygen scavengers made up of substances which chemically or enzymically react with oxygen were developed to remove oxygen. The commercial oxygen scavengers such as “ageless sachet”, “platinum catalyst”, and “glucose/oxidase enzyme” have been greatly discussed in their action mechanisms and applications. The use of antioxidants in packaging manufacture has so far been limited to stabilizing the polymer during the processing or retarding the change of polymer's physical properties during storage when UV irradiated. However, a further benefit derived from incorporation of an antioxidant into the polymer is more interesting for its ability to retard lipid oxidation of the packaged food via slow migration of an antioxidant from the polymer to food. In view of which, in this paper we will review some oxygen scavenger systems as well as antioxidant-impregnated or antioxidant-coated polymer packaging material.

The biosensor technology, which makes it possible to detect biomaterial such as protein, pathogen, and small molecules, is useful in such areas as diagnosis, bioprocessing, and food analysis or safety. For the development of a highly sensitive biosensor, immobilization techniques of organic/bio films on solid substrate, and detection methods of protein-protein reactions appearing in a few nanometers region from the sensor surface should be established. In this review, several immobilization techniques and detection methods are reviewed based on the articles reported recently.