• 한국지반공학회지:지반
• /
• 제13권6호
• /
• pp.45-60
• /
• 1997

본 논문에서는 새로 제안된 외말뚝의 횡하중에 대한 거동과 사면에서의 억지말뚝으로서의 거동에 관하여 연판하였다. 특히 기존의 원형PC말뚝을 대신할 수 있는 새로운 말뚝의 단면을 실험을 통하여 결정하고 이에 대하여 외 말뚝으로서의 수평력에 대한 거동과 사면에서의 안전율 증진 효과를 고찰하였다. 연구 결과 새로운 형태의 말뚝은 외말뚝으로서는 동일한 청하중에 대하여 말뚝의 최대 변위량 이 기존의 원형PC말뚝보다 훨씬 작은 것으로 평가되었으며, 허용변위량에 대한 수평 하중은 증가하였다. 또한 사면에서의 거동을 비교한 결과 동일한 조건에서 안전율이 원형 PC말뚝보다 증가하며 안전율을 동일하게 할 경우 원형PC말뚝보다 말뚝의 수량을 줄일 수 있어 더 경제적이라 할 수 있을 것이다.

• 한국고분자학회:학술대회논문집
• /
• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
• /
• pp.86-88
• /
• 2006

The novel linear- (V-LUM) and cross-type macromonomers (C-VUM) of vinyl-terminated bifunctional polyurethane were synthesized and applied to the dispersion polymerization of styrene and MMA in ethanol. The existence of the vinyl terminal groups and the grafted macromonomer with styrene and PMMA was verified using 1H NMR and 13C NMR. Monodisperse polystyrene (PS) microspheres were successfully obtained above 15 wt % of macromonomer relative to styrene. The macromonomer can efficiently stabilize higher surface area of the particles compared to a conventional stabilizer, PVP. The grafting ratio of the PS calculated from 1H NMR linearly increased up to 0.048 with 20 wt % of the macromonomer and the high molecular weights (501,300 g/mol) of PS with increased glass transition and enhanced thermal stability were obtained. Furthermore, the stable and monodisperse PMMA microspheres having a weight-average diameter of $5.09{\mu}m$ and a good uniformity of 1.01 were obtained with 20 wt% L-VUM. The molecular weight increased, but the size of the PMMA particles decreased with the macromonomer concentration due to the increased stabilizing effect. The molecular weight of the PMMA was approximately two fold higher than that by a conventional PVP. The L-VUM acts as a reactive stabilizer, which gives polyurethane-grafted PS or PMMA with a high molecular weight. In addition, the XPS result showed that the C-PS (PS using the C-VUM) was anchored with a larger amount of PEG than that of the L-PS (PS using the L-VUM) on the particle surface. Thus, the reaction and stabilizing mechanism of the macromonomers for the formation of PS particles is proposed.

• 한국지반공학회논문집
• /
• 제15권5호
• /
• pp.157-170
• /
• 1999

본 연구에서는 억지말뚝을 이용한 점성토지반 절토사면에 대한 새로운 설계법이 제안된다. 이 설계법에서는 사면의 기울기와 높이, 억지말뚝열의 수와 설치위치, 말뚝의 간격과 강성 등의 요소를 체계적으로 선택할 수 있게 되어 있다. 이 설계법은 줄말뚝을 포함한 사면의 안정해석법에 근거하여 확립될 수 있다 말뚝으로 사면을 안정시킬 수 있는 기본적인 개념은 줄말뚝이 산사태와 같은 측방변형지반속에 설치되어 있을 경우 말뚝사이의 지반이 지반아칭현상에 의하여 억지 될 수 있다는데 있다. 줄말뚝을 포함한 사면의 전체안정을 검토하기 위하여 말뚝안정해석과 사면안정해석이 동시에 실시되어야 한다. 제안된 설계법에 따라 설계된 점성토지반 절토사면에 계측기를 설치하여 말뚝 및 말뚝사이 지반의 거동을 면밀히 관찰하였다. 이를 통하여 점성토지반 절토사면에 설치된 억지말뚝의 사면안정효과를 확인할 수 있었다.

• BMB Reports
• /
• 제46권1호
• /
• pp.47-52
• /
• 2013

Intestinal epithelial cell (IEC) apoptosis induced by hypoxia compromise intestinal epithelium barrier function. Both Akt and Hsp90 have cytoprotective function. However, the specific role of Akt and $Hsp90{\beta}$ in IEC apoptosis induced by hypoxia has not been explored. We confirmed that hypoxia-induced apoptosis was reduced by $Hsp90{\beta}$ overexpression but enhanced by decreasing $Hsp90{\beta}$ expression. $Hsp90{\beta}$ overexpression enhanced BAD phosphorylation and thus reduced mitochondrial release of cytochrome C. Reducing $Hsp90{\beta}$ expression had opposite effects. The protective effect of $Hsp90{\beta}$ against apoptosis was negated by LY294002, an Akt inhibitor. Further study showed that Akt phosphorylation was enhanced by $Hsp90{\beta}$, which was not due to the activation of upstream PI3K and PDK1 but because of stabilization of pAkt via direct interaction between $Hsp90{\beta}$ and pAkt. These results demonstrate that $Hsp90{\beta}$ may play a significant role in protecting IECs from hypoxia-induced apoptosis via stabilizing pAkt to phosphorylate BAD and reduce cytochrome C release.

• Advances in Traditional Medicine
• /
• 제7권4호
• /
• pp.395-408
• /
• 2007

This study reports the analgesic, anti-inflammatory and membrane-stabilizing property of alcoholic extract of Ophiorrhiza nicobarica (ON), a wild herb, used as an anti-infective ethnomedicine of Nicobarese and Shompen tribes of Great Nicobar Island, India. We for the first time investigated the analgesic and antiinflammatory potential of this herb in acute, subacute and chronic model of inflammation in Swiss albino mice and Wistar albino rats, along with sheep RBC-induced sensitivity and membrane stabilization. The acetic acid induced writhing, tail flick and tail immersion tests are used as a model for evaluating analgesic activity; while the carrageenin-induced paw oedema was used as the model for acute inflammation, dextran-induced oedema as sub-acute and cotton-pellateinduced granuloma as chronic inflammatory model. The probable mode by which ON mediate its effect on inflammatory conditions was studied on sheep RBC-induced sensitivity and membrane stabilization. The in vitro results revealed that the ON extract possesses significant (P < 0.05) dose dependent analgesic and antiinflammatory activity at 200 and 300 mg/kg and its fractions at 50 mg/kg, p.o. respectively, compared to the control groups. However, the extract failed to exhibit membrane-stabilizing property as it unable to reduce the level of haemolysis of RBC exposed to hypotonic solution. The acute toxicity studies of ON extract in rats and mice revealed that the extract was nontoxic even up to 3.0 g/kg body weight of the animals, with a high safety profile. We have isolated ursolic acid, ${\beta}$-sitosterol and harmaline respectively, from the bioactive part of the extract. The results indicated that the O. nicobarica is indeed beneficial in primary health care, and suggest that its anti-inflammatory activity may not be related to membrane-stabilization.

• 한국산림과학회지
• /
• 제101권4호
• /
• pp.656-662
• /
• 2012

본 연구는 경북 울진군에 조성된 해안방재림을 대상으로 식재된 해송의 생장특성을 조사하고 생장에 영향을 미치는 인자와의 관계를 규명하고자 수행하였다. 총 9개소 3,600본의 해송을 4년간 모니터링 하였으며, 식재위치에 따라 서로 다른 생장량이 조사되었다. 생장에 영향을 미치는 생육환경인자로 풍속과 전기전도도, 토양산도, 토양습도 등의 토양조건을 조사하여 생장량과의 관계를 분석하였다. 연구결과 풍속이 식재된 해송의 생장과 가장 밀접한 관련을 가지는 것으로 분석되었으며, 토양조건 역시 풍속에 따라 크게 영향을 받았다. 따라서 해안방재림으로 조성된 해송의 생장량을 높이기 위해서는 풍속의 효과적인 제어가 가장 중요하며, 향후 이를 위한 퇴사울의 개발과 그 효과에 대한 장기적인 모니터링이 필요할 것으로 사료된다.

• 폴리머
• /
• 제38권5호
• /
• pp.671-675
• /
• 2014

본 연구에서는 잘 규정된 4-arm 스타형 및 선형 고분자를 합성하여 구조에 따른 구리 프탈로시아닌(CuPc)의 분산 안정성을 비교하였다. 분산제는 (2-dimethylamino)ethyl methacrylate(DMAEMA)와 poly(ethylene glycol) methyl ether methacrylate(PEGMA)를 사용하여 activators generated by electron transfer(AGET) 원자이동라디칼중합법(ATRP)으로 합성하였다. 합성된 고분자는 젤투과 크로마토그래피(GPC)와 핵자기 공명 분광법(NMR)을 사용하여 합성한 고분자들의 분자량 및 단량체의 조성을 결정하였다. 4-Arm 스타형 고분자 및 선형 고분자 분산제에서 stabilizing group인 PEGMA의 중합도를 조절하여 copper phthalocyanine(CuPc)의 분산 안정성에 미치는 영향을 연구하였다. PEGMA의 DP가 130인 4-arm 스타형 고분자를 사용한 경우 $25^{\circ}C$에서 7일 동안 CuPc의 분산상이 안정적으로 유지되었다.

• Journal of Microbiology and Biotechnology
• /
• 제26권2호
• /
• pp.337-346
• /
• 2016

Three combinations of molecular chaperones from Escherichia coli (i.e., DnaK-DnaJ-GrpE-GroEL-GroES, GroEL-GroES, and DnaK-DnaJ-GrpE) were overproduced in E. coli BL21, and their in vitro stabilizing effects on a nitrile hydratase (NHase) were assessed. The optimal gene combination, E. coli groEL-groES (ecgroEL-ES), was introduced into Rhodococcus ruber TH3. A novel engineered strain, R. ruber TH3G was constructed with the native NHase gene on its chromosome and the heterologous ecgroEL-ES genes in a shuttle plasmid. In R. ruber TH3G, NHase activity was enhanced 37.3% compared with the control, TH3. The in vivo stabilizing effect of ecGroEL-ES on the NHase was assessed using both acrylamide immersion and heat shock experiments. The inactivation behavior of the in vivo NHase after immersion in a solution of dynamically increased concentrations of acrylamide was particularly evident. When the acrylamide concentration was increased to 500 g/l (50%), the remaining NHase activity in TH3G was 38%, but in TH3, activity was reduced to 10%. Reactivation of the in vivo NHases after varying degrees of inactivation was further assessed. The activity of the reactivated NHase was more than 2-fold greater in TH3G than in TH3. The hydration synthesis of acrylamide catalyzed by the in vivo NHase was performed with continuous acrylonitrile feeding. The final concentration of acrylamide was 640 g/l when catalyzed by TH3G, compared with 490 g/l acrylamide by TH3. This study is the first to show that the chaperones ecGroEL-ES work well in Rhodococcus and simultaneously possess protein-folding assistance functions and the ability to stabilize and reactivate the native NHases.

• Biomaterials and Biomechanics in Bioengineering
• /
• 제3권1호
• /
• pp.37-46
• /
• 2016

To maintain activity in a coenzyme/enzyme mixture system, such as ${\beta}$-nicotinamide adenine dinucleotide (NADH)/dehydrogenase, the water-soluble 2-methacryloyloxyethyl phosphorylcholine (MPC) polymers as an additive were synthesized and investigated for their stabilizing function. The inhibitor for the NADH/dehydrogenase reaction was spontaneously formed when the NADH was stored in the dehydrogenase solution. Therefore, we hypothesized that if the additive polymer could interact with an inhibitor without any adverse effect on the dehydrogenase, the activity in the NADH/dehydrogenase mixture could be maintained. We selected lactose dehydrogenase (LDH) as the enzyme, and the NADH was dissolved and incubated at $37^{\circ}C$ in the LDH solution containing the polymers. The phospholipid polymers used in this study were poly(MPC) (PMPC), poly(MPC-co-3-trimethylammonium-2-hydroxypropyl methacrylate chloride) (PMQ) and poly[MPC-co-potassium 3-methacryloyloxypropyl sulfonate ($MSO_3$)] ($PMMSO_3$). The poly($MSO_3$) was used as a reference. For the PMQ and $PMSO_3$ aqueous solutions, the activity of the NADH/LDH mixture system decreased with incubation time as the same level or lower than that in the Tris buffered solution in the absence of the polymers. However, for the poly($MPC-co-MSO_3$) ($PMMSO_3$) aqueous solution, the activity of the NADH/LDH mixed system was six times higher than that in the buffered solution even after a 3-days incubation. The LDH activity was 1.5-1.8 times higher in the presence of the $PMMSO_3$ compared with that in the $PMSO_3$ solution. The mixture of two polymers, poly(MPC) and poly($MSO_3$), did not produce any stabilization. Thus, both the MPC and $MSO_3$ units in the polymer chain had important and cooperative effects for stabilizing the NADH/LDH mixture.

• Journal of Electrical Engineering and Technology
• /
• 제10권6호
• /
• pp.2413-2419
• /
• 2015

Core spinal muscles are related to trunk stability and assume the main role of stabilizing the spine during daily activities; strengthening of core muscles around the spine can therefore reduce the chance of back pain. The objective of the study was to investigate the effect of core muscle strengthening in the spine during spine stabilization exercise using a whole body tilt device. To achieve this, a validated musculoskeletal (MS) model of the whole body was used to replicate the input motion from the whole body tilting exercise. An inverse dynamics analysis was executed to estimate spine loads and muscle forces depending on the tilting angles of the exercise device. The activation of long and superficial back muscles such as the erector spinae (iliocostalis and longissimus) were mainly affected by the forward direction (-40°) of the tilt, while the front muscles (psoas major, quadratus lumborum, and external and internal obliques) were mainly affected by the backward tilting direction (40°). Deep muscles such as the multifidi and short muscles were activated in most directions of the rotation and tilt. The backward directions of the tilt using this device could be carefully applied for the elderly and for rehabilitation patients who are expected to have less muscle strength. In this study, it was shown that the spine stabilization exercise device can provide considerable muscle exercise effect.