Earticle

Room temperature magnetic refrigeration is a new highly efficient and environmentally protectivetechnology. Gd is most useful magnetic material for magnetic refrigerator. Tc of Gd is about 293K. ∆SM is4.36 and 2.97J/kg K at ∆H=1.5T and 1T respectively. ∆Tad is about 4.32K at ∆H=2T. Gd-B alloys ismanufactured by arc melting method. Tc is about 296K. ∆SM decrease from 4.36 to 3.98J/kg K at ∆T=1.5Tand ∆Taddecrease from 4.32 to 3.81K at ∆H=2T with increasing B constituents.

The present study was intended to examine a basic scheme to determine the biochemical oxygen demand(BOD) of livestock wastewater by means of six individual dissolved oxygen (DO) sensors and its multi-measurablemeter. Maximal point of the first order time derivative of the DO difference between DO distribution of sterilizedlivestock wastewater and that of non-sterilized livestock wastewater, was considered as the oxygen uptake rate (OUR)of microorganisms in livestock wastewater, as determined to be 0.00074mg O2/ℓ.sec. The present study showed thatthere was a fair linear relationship (97.72%) between maximal OUR and BOD values of livestock wastewater, the latterbeing determined by classical Winkler azide method. It was thus concluded that the present multi-biosensor systemmight be applicable to an on-line system for measurement of BOD of livestock wastewater.

교통사고나 낙상, 운동등에 의해 가장 흔히 일어나는 질병중 하나인 척수손상은 환자 본인은 물론 가족에게까지 육체적, 정신적, 심리적 장애는 물론 경제적으로도 큰 손실을 초래하는 심각한 질병이다.척수손상을 입게되면 감각, 운동 신경에 장애가 오게 되며 손상 받은 부위와 정도에 따라 전신 혹은 신체일부의 마비를 가져 올 뿐만 아니라 방광과 대장기능을 조절하는 자율신경의 기능 또한 상실하게 되며 다양한 임상증상을 보이게 된다. 척수 손상은 직접적인 충격 손상이나 파열 및 계속적인 압착 등 물리적 자극에 의한 일차적 손상과 이러한 일차적 손상으로 인해 유발되는 생화학적 변화에 의한 이차적 손상으로 나뉘어 진다. 이러한 척수 손상을 치료하기 위해서는 일부 살아남은 신경세포의 기능을 회복시키거나 손상된 척수 신경의 재생이 반드시 필요하다. 이러한 문제를해결하기 위해 성장 억제 인자의 중화, 축삭의 신장을 돕는 세포나 조직의 이식, 그리고 축삭의 성장을 증진시키는신경성장인자의 투여등 다양한 연구가 진행되어 오고 있으며 최근에는 만능세포라 불리는 줄기세포를 손상 받은척수에 이식함으로써 기능 회복이 가능하다는 보고 또한 있다. 한편 척수 손상의 치료를 위해 전통의학이외에 대체의학적인 접근이 시도되고 있다. 이러한 세포치료를 임상에 적용하기 위해서는 아직까지 풀어야 할 과제가 많이남아있지만 척수 손상을 치료하기 위한 연구자들의 밤 낮 없는 열정은 많은 척수장애인들에게 큰 희망이 되고 있음은 틀림 없는 사실이다.

This study was designed to investigate the differential effects of tumor promotors on prostaglandinproduction and COX-2 expressionin raw264.7 macrophage cells. Tumor promotors such as thapsigargine, okadaic acidand PMA stimulated TXB2 synthesis at the doses of 1 ng/ml to 1 µg/ml. But staurosporine showed differential effectsat the same range of doses. At higher dose (>100 ng/ml) staurosporine significantly reduced TXB2 synthesis, but atlower doses, it stimulated TXB2 synthesis. When cotreated, thapsigargine and PMA reduced LPS-induced TXB2production. However okadaic acid and staurosporine showed dual effects depending on the concentration. The effectsof tumor promotors on COX-2 expression paralleled their effects on TXB2 synthesis. These results shows tumorpromotors affects COX-2 expression in a different way and thereby suggest differential contribution of COX-2 duringthe process of tumor promotion stimulated by particular agents.

We study for the magnetic and electronic properties of V- and Mn-doped hexagonal ZnO and cubic GaNby using the full-potential linear muffin-tin orbital method. The calculations are made at several concentrations fromabout 4 to 12% of dopant atoms in the 48 and 64 atoms supercell for ZnO and GaN, respectively. For Zn1-xMxO (M=Vand Mn) at x=0.083 (pair impurities), the energetically favorable magnetism is the antiferromagnetic states. For V-dopedZnO with the defect, the results show that it is strongly correlated between the energy states by the defect of Zn or Osite and those by V impurity in ZnO.