• 공업화학
• /
• 제33권2호
• /
• pp.195-201
• /
• 2022

본 연구에서는 지황 추출물[Rehmannia glutinosa extract (RE)]이 함유된 chitosan (CH) 기반 바이오 소재를 제조하고, 물리·화학적 특성, RE 방출 특성, 멜라닌 합성 억제 효과, 항산화 효과, elastase 억제 효과를 조사하였다. RE 함유 CH기반 바이오 소재는 casting method와 UV 경화 공정을 통해 제조되었다. 제조된 바이오 소재의 표면 특성은 FE-SEM으로 분석하였고, 물리적 특성은 인장강도, 신축률을 통하여 조사하였다. 경피 약물 전달 시스템을 적용하기 위해 36.5 ℃에서 pH 4.5, pH 5.5, pH 6.5 용액에서와 인공피부를 이용해 제조된 바이오 소재에서 RE의 방출 특성을 조사하였으며, 그 결과, pH 6.5에서 가소제를 첨가하지 않은 바이오 소재와 가소제[glycerol (GL)와 citric acid (CA)]를 첨가하여 제조한 RE 함유 바이오 소재에서 RE의 방출이 pH 4.5에서 보다 약 1.10배 빠르게 일어남을 알 수 있었다. 또한, 인공 피부에서 RE의 방출은 약 6 h 동안 지속적으로 방출됨을 확인하였다. Tyrosinase assay, 2,2-diphenyl-1-picrylhydrazyl(DPPH) assay, elastase assay를 통해 기능성을 평가하였으며, 가소제로 CA를 첨가하고 RE가 함유된 바이오 소재에서 각각 45.12%의 tyrosinase 활성율, 89.40%의 DPPH 라디칼 소거능, 59.94%의 elastase 활성율을 나타내었다.

• Animal cells and systems
• /
• 제3권3호
• /
• pp.331-336
• /
• 1999

p56$^{Ick}$, a cytoplasmic protein tyrosine kinase of the src family, is non-covalently associated with the cell surface coreceptors CD4 and CD8, which are expressed on thymocytes and mature T cells. The coreceptor protein plays an important role during the differentiation of thymocytes and the activation of T cells. DNA constructs were designed to study the roles of CD4 and CD8 during the differentiation of thymocytes. One is a chimeric cDNA which consists of coding regions for the extracellular domain of CD8a and the transmembrane and cytoplasmic domain of CD4. The other is the same chimeric cDNA but with a point mutation converting Cys to Ala in the Ick-binding site to disrupt the association. We confirmed that the CD8a/CD4 chimeric molecule bound to Ick more efficiently than the wild type CD8a protein. However, the chimeric protein with the Cys$leftrightarro$Ala mutation did not associate with Ick. The results suggest a possibility that the CD8a/CD4 chimeric protein may behave like a CD4 protein in associating with Ick and that it may deliver a signal inside the cell in a similar manner, Analysing effects of the mutant CD8a/CD4 chimeric protein expression in developing thymocytes will elucidate the role of Ick during the determination of CD4/CD8 cell lineages.

• ALGAE
• /
• 제18권2호
• /
• pp.121-127
• /
• 2003

The pyrenoid ultrastructure and distribution of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) and Rubisco activase in the chloroplasts of Chlamydomonas reinhardtii was studied using the immunogold localization technology with electron microscopy. There were several tubular thylakoids invading in the pyrenoid matrix to form several spokewise channels. The connections between pyrenoid matrix and stroma of chloroplast were the partial of channels. The starch sheath surrounding the pyrenoid was separated into several parts by the connections in transection. Some thylakoids were packed together near the connections in one side of the pyrenoid. Those special structures might be used to transport substance between pyrenoid and stroma of chloroplasts. With the antibody raised against the large subunits of Rubsico from C. protothecoides, the result of the gold immunolocalization of Rubisco in Chlamydomonas reinhardtii showed most of the gold particles heavily labeled the pyrenoid matrix, as well as the starch sheath matrix, and very few in the stroma of chloroplasts. The gold particle density was 880.00 $\pm$ 164.32, 190.00 $\pm$ 152.39 and 9.60 $\pm$ 5.37 ${\mu}m^{-2}$ in pyrenoid matrix, starch sheath and stroma region of chloroplast respectively (background: 5.67 $\pm$ 1.53 ${\mu}m^{-2}$). 99.59% of the total Rubiscos was calculated to be concentrated in the pyrenoid matrix and starch sheath by spatial densities. The gold immunolocalization of Rubisco activase also showed that Rubisco activase was mainly concentrated in the periphery of the pyrenoid and the starch sheath (the density was as high as 229.69 $\pm$ 96.96 ${\mu}m^{-2}$). There were very few gold particles located in the stroma of chloroplasts. These results indicated that pyrenoid surface and starch sheath was the site for Rubisco activation and $CO_2$ fixation, which supported the suggestion that pyrenoids perform photosynthesis function.

• 공업화학
• /
• 제21권4호
• /
• pp.417-423
• /
• 2010

파라자일렌(p-xylene) 분리용 흡착제로서 효과적인 그래뉼 형태의 바인더리스 ZSM-5 성형체를 제조하는 방법을 검토하였다. $SiO_2/Al_2O_3$ = 50인 ZSM-5 결정분말에 무기 바인더인 colloidal silica sol 30 wt% 용액과 유기첨가물인 microcrystalline cellulose를 첨가하여 구형화한 후, 소성, 바인더리스 처리, ${NH_4}^+$ 이온교환, 활성화 등의 과정을 거쳐 충분한 강도(0.721 kgf) 및 높은 결정화도(94.6%)와 넓은 BET 비표면적($379.2m^2$/g)을 갖는 흡착제를 제조하였다. 제조된 성형체의 흡착특성을 평가하기 위해 자일렌 3가지 이성질체를 1 : 1 : 1의 무게비로 혼합하여 $100^{\circ}C$에서 회분식 흡착실험을 수행한 결과 제조된 바인더리스 ZSM-5 성형체는 상용흡착제보다 파라자일렌에 대해 높은 선택적 흡착성능을 나타냈다.

• Asian-Australasian Journal of Animal Sciences
• /
• 제24권5호
• /
• pp.696-706
• /
• 2011

The objective of this study was to characterize serum immunoglobulins and lymphocytes subpopulations in the peripheral blood mononuclear cells (PBMCs) of Holstein calves in response to lipopolysaccharide (LPS) challenge from Escherichia coli. Fourteen calves received subcutaneous injections of E. coli LPS at 10 weeks of age, and six calves were injected with saline as a control. The concentrations of total serum IgG and the relative amount of LPS-specific IgG in calves challenged with LPS were significantly higher (p<0.05) compared to control animals and LPS challenge significantly increased (p<0.05) the percentage of $CD5^+$ and $CD21^+$ T cells in PBMCs. Meanwhile, LPS challenge significantly increased (p<0.05, p<0.01) the percentage of $CD8^+$ and $CD25^+$ T cells in peripheral blood mononuclear cells (PBMC) at 7 and 14 Day-post LPS challenge (DPLC), respectively. The composition of $CD4^+CD25^+$ T cells and $CD8^+CD25^+$ T cells from calves challenged with LPS was also higher (p<0.05 and p = 0.562, respectively) than those of control calves at 14 DPLC. In conclusion, LPS challenge not only induces production of IgG with expression of B-cell immune response related cell surface molecules, but also stimulates activation of T-lymphocytes in PBMC. Our results suggest that LPS challenge in calves is a good model to elucidate cellular immune response against Gram-negative bacterial infections.

• 대한화학회지
• /
• 제52권2호
• /
• pp.124-132
• /
• 2008

H3SO4(M: 몰농도) 용액에서 탄소강의 부식방지제로 Furfural hydrazone 유도체의 효과를 질량손실법 및 정전류극성법을 사용해 연구하였다. 이들 유도체 존재하에서 탄소강의 부식속도가 급격히 감소함을 관찰하였다. 이 연구로부터 부식방지효율은 부식방지제 농도가 증가함에 따라 증가하였고 I와 SCN을 첨가하면 부식방지효율은 더욱 증가되었다. 질량손실법을 사용해 5×10-6 M의 유도체가 있을 때와 없을 때 30-60oC 사이에서 탄소강 부식에 미치는 온도 효과를 보았다. 부식과정에 대한 활성화에너지(Ea*)와 다른 열역학적 변수들을 계산하였고 이들에 대해 논의하였다. 정전류극성법을 통해 유도체들이 혼합형 방지제로 작용함을 알았고 외부전류를 흘려주었을 때 음극은 더욱 분극되었다. 3M H3SO4 용액에서 탄소강 표면에 이들 유도체들의 흡착은 Frumkin의 흡착등온을 따랐다. 이들 유도체들의 화학구조를 통해 부식방지 메커니즘을 설명하였다.

• Corrosion Science and Technology
• /
• 제12권2호
• /
• pp.102-112
• /
• 2013

A very high-temperature gas reactor (VHTR) is one of the next generation nuclear reactors owing to its safety, high energy efficiency, and proliferation-resistance. Heat is transferred from the primary helium loop to the secondary helium loop through an intermediate heat exchanger (IHX). Under VHTR environment Alloy 617 is being considered a candidate Ni-based superalloy for the IHX of a VHTR, owing to its good creep resistance, phase stability and corrosion resistance at high temperature. In this study, high-temperature corrosion tests were carried out at 850 - $950^{\circ}C$ in air and impure helium environments. Alloy 617 specimens showed a parabolic oxidation behavior for all temperatures and environments. The activation energy for oxidation was 154 kJ/mol in helium environment, and 261 kJ/mol in an air environment. The scanning electron microscope (SEM) and energy-dispersive x-ray spectroscopy (EDS) results revealed that there were a Cr-rich surface oxide layer, Al-rich internal oxides and depletion of grain boundary carbide after corrosion test. The thickness and depths of degraded layers also showed a parabolic relationship with the time. A corrosion rate of $950^{\circ}C$ in impure helium was higher than that in an air environment, caused by difference in the outer oxide morphology.

• Asian Pacific Journal of Cancer Prevention
• /
• 제13권9호
• /
• pp.4827-4834
• /
• 2012

Tumor suppressor genes have received much attention for their roles in the development of human malignancies. Gelsolin has been found to be down-regulated in several types of human cancers, including leukemias. It is, however, expressed in macrophages, which are the final differentiation derivatives for the monocytic myeloid lineage, implicating this protein in the differentiation process of such cells. In order to investigate the role of gelsolin in leukaemic cell differentiation, stable clones over-expressing ectopic gelsolin, and a control clone were established from U937 leukaemia cells. Unlike the control cells, both gelsolin-overexpressing clones displayed retarded growth, improved monocytic morphology, increased NADPH and NSE activities, and enhanced surface expression of the ${\beta}$-integrin receptor, CD11b, when compared with the parental U937 cells. Interestingly, RT-PCR and western blot analysis also revealed that gelsolin enhanced p21CIP1 mRNA and protein expression in the overexpressing clones. Moreover, transient transfection with siRNA silencing P21CIP1, but not the control siRNA, resulted in a reduction in monocytic differentiation, accompanied by an increase in proliferation. In conclusion, our work demonstrates that gelsolin, by itself, is capable of inducing monocytic differentiation in U937 leukaemia cells, most probably through p21CIP1 activation.

• 대한물리의학회지
• /
• 제12권3호
• /
• pp.59-66
• /
• 2017

PURPOSE: This study was to evaluate the muscle activity of gluteus medius, tensor fascia latae, and quadratus lumborum during side-lying abduction exercise in various pelvic tilting positions. METHODS: We measured the activity of three muscles in three pelvic tilt positions for 17 normal subjects with performing the side-lying hip abduction. Three pelvic tilt positions were posterior tilt, neutral tilt and anterior tilt. We used the mean value after participants performed the hip abduction three times each position. RESULTS: The activity of gluteus medius within three pelvic positions showed the highest activity in pelvic posterior tilt position and the lowest in pelvic neutral tilt position (p = .04). The activity of tensor fascia latae showed the lowest in pelvic posterior tilt position and the highest in pelvic posterior tilt position (p = .00). The activity of quadratus lumborum revealed the lowest activity in pelvic neutral tilt position and the highest in pelvic anterior tilt position (p = .00). The activity of selective gluteus medius activation according to pelvic displacement showed the highest activity in pelvic neutral tilt position and lowest in pelvic anterior tilt position (p = .00). CONCLUSION: Hip abduction with Pelvic posterior tilt position may be effective in increasing gluteus medius and may be effective in strengthening exercise program for the gluteus medius. In addition, Hip abduction with pelvic neutral position may have an effect on the selective gluteus medius, which is considered to be effective in the exercise program for muscle reeducation training of the gluteus medius.

• 한국전문물리치료학회지
• /
• 제25권2호
• /
• pp.62-70
• /
• 2018

Background: The craniocervical flexion (CCF) exercise is one of the effective exercise in correcting forward head posture (FHP). However, some people with FHP achieve CCF with compensatory movements, for example, low cervical flexion using superficial neck flexors such as the sternocleidomastoid (SCM) muscle. No study has yet investigated whether a dual­pres ure biofeedback unit (D-PBU) method to prevent low cervical flexion would be helpful in performing pure CCF movement. Objects: The purpose of this study was to compare the effects of the CCF using D-PBU method and the traditional CCF method on the cross-sectional area (CSA) of the longus colli muscle (LCM) and the activity of SCM muscle in subjects with FHP. Methods: Twenty­four FHP subjects (male: 16, female: 8) were recruited for this study. All subjects performed CCF using two different methods: the traditional CCF method and the CCF using D-PBU method. The CSA of the LCM was measured via ultrasound, and surface electromyography was used to measure SCM muscle activity. Results: The change in CSA of the LCM was significantly larger during the CCF using D-PBU method ($1.28{\pm}.09$) compared with the traditional CCF method ($1.19{\pm}.08$) (p<.05). The SCM muscle activity using the CCF using D-PBU method ($2.01{\pm}1.97$ %MVIC) was significantly lower than when using the traditional CCF method ($2.79{\pm}2.32$ %MVIC) (p<.05). Conclusion: The CCF using D-PBU method can be recommended for increasing LCM activation and decreasing SCM muscle activity during CCF movement in subjects with FHP.