• Composites Research
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• 제20권3호
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• pp.50-54
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• 2007

본 연구에서는 IPMC의 기본적인 기계적 특성을 알아보았다. 기전폴리머의 한 종류인 IPMC는 굽힘형 작동, 가벼움, 저전력 소모, 유연성 등의 많은 장점을 가진 재료이다. 따라서 IPMC는 생체모방형 작동기와 센서로서 많은 가능성을 가지고 있다. 이런 가능성을 바탕으로 IPMC를 실제로 응용하기 위하여 IPMC의 변형, 구동력, 주파수 응답 등 기본적인 기계적 특성을 연구하였다. 우선 이온교환폴리머의 한 종류인 네피온 용액을 사용하여 여러 가지 두께의 네피온 막을 만들고, 무전해 도금을 통해 IPMC를 제작하였다. 이렇게 제작된 IPMC의 규격, 인가 전압에 따른 변형, 구동력, 주파수 응답 특성에 관한 실험을 수행하고, 실험 결과를 통해 IPMC 성능의 실험식과 등가 강성 모델을 수립하였다.

• Biomolecules & Therapeutics
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• 제32권3호
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• pp.267-280
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• 2024

Apoptosis, programmed cell death pathway, is a vital physiological mechanism that ensures cellular homeostasis and overall cellular well-being. In the context of cancer, where evasion of apoptosis is a hallmark, the overexpression of anti-apoptotic proteins like Bcl2, Bcl-xL and Mcl-1 has been documented. Consequently, these proteins have emerged as promising targets for therapeutic interventions. The BCL-2 protein family is central to apoptosis and plays a significant importance in determining cellular fate serving as a critical determinant in this biological process. This review offers a comprehensive exploration of the BCL-2 protein family, emphasizing its dual nature. Specifically, certain members of this family promote cell survival (known as anti-apoptotic proteins), while others are involved in facilitating cell death (referred to as pro-apoptotic and BH3-only proteins). The potential of directly targeting these proteins is examined, particularly due to their involvement in conferring resistance to traditional cancer therapies. The effectiveness of such targeting strategies is also discussed, considering the tumor's propensity for anti-apoptotic pathways. Furthermore, the review highlights emerging research on combination therapies, where BCL-2 inhibitors are used synergistically with other treatments to enhance therapeutic outcomes. By understanding and manipulating the BCL-2 family and its associated pathways, we open doors to innovative and more effective cancer treatments, offering hope for resistant and aggressive cases.

• Asia pacific journal of information systems
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• 제19권2호
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• pp.95-116
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• 2009

Increasingly the institutional theory has been an important theoretical view of decision making process and IT adoption in many academic researches. This study used the institutional theory as a lens through which we can understand the factors that enable the effective appropriation of advanced information technology. It posits that mimetic, coercive, and normative pressures existing in an institutionalized environment could influence the participation of top managers or decision makers and the involvement of users toward an effective use of IT in their tasks. Since the introduction of IT, organizational members have been using IT in their daily tasks, creating and recreating rules and resources according to their own methods and needs. That is to say, the adaptation process of the IT and outcomes are different among organizations. The previous studies on a diverse use of IT refer to the appropriation of technology from the social technology view. Users appropriate IT through not only technology itself, but also in terms of how they use it or how they make the social practice in their use of it. In this study, the concepts of institutional pressure, appropriation, participation of decision makers, and involvement of users toward the appropriation are explored in the context of the appropriation of the mobile electronic medical record system (M-EMRS) in particularly a hospital setting. Based on the conceptual definition of institutional pressure, participation and involvement, operational measures are reconstructed. Furthermore, the concept of appropriation is measured in the aspect of three sub-constructs-consensus on appropriation, faithful appropriation, and attitude of use. Grounded in the relevant theories to appropriation of IT, we developed a research framework in which the effects of institutional pressure, participation and involvement on the appropriation of IT are analyzed. Within this theoretical framework, we formulated several hypotheses. We developed a second order institutional pressure and appropriation construct. After establishing its validity and reliability, we tested the hypotheses with empirical data from 101 users in 3 hospitals which had adopted and used the M-EMRS. We examined the mediating effect of the participation of decision makers and the involvement of users on the appropriation and empirically validated their relationships. The results show that the mimetic, coercive, and normative institutional pressure has an effect on the participation of decision makers and the involvement of users in the appropriation of IT while the participation of decision makers and the involvement of users have an effect on the appropriation of IT. The results also suggest that the institutional pressure and the participation of decision makers influence the involvement of users toward an appropriation of IT. Our results emphasize the mediating effect of the institutional pressure on the appropriation of IT. Namely, the higher degree of the participation of decision makers and the involvement of users, the more effective appropriation users will represent. These results provide strong support for institutional-based variables as predictors of appropriation. These findings also indicate that organizations should focus on the role of participation of decision makers and the involvement of users for the purpose of effective appropriation, and these are the practical implications of our study. The theoretical contribution of this study is lies in the integrated model of the effect of institutional pressure on the appropriation of IT. The results are consistent with the institutional theory and support previous studies on adaptive structuration theory.

• 한국습지학회지
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• 제15권4호
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• pp.501-508
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• 2013

식물종 다양성이 높은 하천변 복원을 위해 8개 하천 13지점에서 자연하천변 식물군락의 이질성을 ${\beta}$-diversity로 조사하였다. 그 결과, 하천에서 내륙으로 들어감에 따른 이질성의 평균값은 0.32이었다(0.23~0.37범위). 이 값은 식물군락의 종 구성이 6번 완전히 바뀌는 community turnover를 나타낸다. ${\beta}$-diversity는 섬진강, 한강, 낙동강, 금강 수계 간에 차이가 없었고, 각 수계 안에서 하천 유역은 하류(0.23)보다 상류(0.36)에서 더 높았다(p level<0.05). 환경요인과의 관계를 알아보기 위해 다중회귀분석을 실시한 결과 ${\beta}$-diversity는 경사도에서 유의성이 나타났다. Belt-transect를 통해 나타난 종들과 ${\beta}$-diversity 값을 통해 하천변의 우점종 모식도를 그려보면 상류의 종조성은 6번 바뀌고, 하류의 종조성은 약 5번 바뀌었다. 본 연구 결과를 통해 하천 계획에 실질적으로 활용할 수 있는 식재 수종과 식재 패턴의 기초를 제시하였으며, 하천변 식물군락의 종 다양성을 높이기 위해서는 경사도를 높이는 것이 가장 중요하다.

• 만화애니메이션 연구
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• 통권44호
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• pp.235-261
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• 2016

인터넷 및 디지털 미디어의 환경에서 미디어 수용자는 동일 콘텐츠를 다양한 플랫폼으로 이용하고 있다. 이처럼 여러 장르의 콘텐츠가 디지털 미디어의 기반에서 융합, 조합, 변형, 분화, 복제 등의 과정을 거치면서 새로운 콘텐츠의 형태로 전환되는 것을 트랜스미디어라고 한다. 트랜스미디어 시대에서 성공하는 콘텐츠를 만들기 위해서는 에디큐레이션의 작업이 필요하다. 에디큐레이션은 큐레이터의 큐레이션 작업에 편집과 의미를 부가하는 작업 행위이다. 그런 점에서 이 논문은 트랜스미디어 시대에서 출판 및 만화 콘텐츠의 에디큐레이션에 대한 정의와 의미를 분석했다. 에디큐레이션은 디지털 미디어 환경에서 콘텐츠의 생산자가 곧 소비자며, 소비자가 곧 생산자인 프로컨슈머/프로듀저를 유도하는 역할을 담당하는 프로세스다. 디지털 플랫폼과 디바이스의 다양화, 디지털 1인(혹은 SNS) 미디어의 등장 등은 출판 및 만화 콘텐츠에도 다양한 방식의 에디큐레이션을 요구한다. 미디어 생산자(혹은 수용자)의 의도에 따라 콘텐츠는 복제, 짜깁기, 분해, 해체, 하이퍼텍스트, 압축, 재구성 등의 과정을 거쳐서 새로운 콘텐츠로 탄생한다. 이처럼 에디큐레이션의 작업을 거친 출판 및 만화 콘텐츠는 미디어 생산자의 작업 방식은 물론, 미디어 수용자의 콘텐츠 독법에도 영향을 미친다는 점에서, 트랜스미디어 시대의 에디큐레이션은 중요한 의미를 지닌다. 출판 콘텐츠에서 에디큐레이션 작업은 챕터나 단락의 논리성 파괴, 구어체의 문장, 카드 뉴스의 활용, 동영상 및 미디어 콘텐츠의 변형 등이 있으며, 만화 콘텐츠에서는 칸의 파괴, 말풍선, 의성어, 의태어의 다양한 변형 등을 들 수 있다.

• 한국자기공명학회논문지
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• 제11권2호
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• pp.85-94
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• 2007

Vanilloid receptor I [transient receptor potential vanilloid subfamily member 1 (TRPV1), also known as VR1] is a non-selective cationic channel activated by noxious heat, vanilloids, and acid, thereby causing pain. VR1 possesses six transmembrane domain and N-and C-terminus cytosolic domains, and appears to be a homotetramer. We studied the structural properties of Cterminus of VR1 (VR1C) using CD and NMR spectroscopy. DPC micelles, with a zwitterionic surface, and SDS micelles, with a negatively charged surface, were used as a membrane mimetic model system. Both SDS and DPC micelles could increase the stability of helical structures and/or reduce the aggregation form of the VR1C. However, the structural changing mode of the VR1C induced by the SDS and DPC micelles was different. The changes according to the various pHs were also different in two micelles conditions. Because the net charges of the SDS and DPC micelles are negative and neutral, respectively, we anticipate that this difference might affect the structure of the VR1C by electrostatic interaction between the surface of the VR1C and phospholipids of the detergent micelles. Based on these similarity and dissimilarity of changing aspects of the VR1C, it is supposed that the VR1C probably has the real pI value near the pH 7. Generally, mild extracellular acidic pH ($6.5{\sim}6.8$) potentiates VRI channel activation by noxious heat and vanilloids, whereas acidic conditions directly activate the channel. The channel activation of the VRI might be related to the structural change of VR1C caused by pH (electrostatic interactions), especially near the pH 7. By measuring the $^1-^{15}N$ TROSY spectra of the VR1C, we could get more resolved and dispersed spectra at the low pH and/or detergent micelles conditions. We will try to do further NMR experiments in low pH with micelles conditions in order to get more information about the structure of VR1C.

• 약학회지
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• 제56권3호
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• pp.191-197
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• 2012

We previously reported that the novel isoflavone-free peptide mixture (black soybean peptide, BSP) had several beneficial effects like antiobesity and hypotriglyceridemic effect. However, there are no reports for BSP on anti-hypertensive activity. BSP induced heme oxygenase-1 (HO-1) in HUVECs, thus investigated the HO-1-induced activity in HUVECs and the anti-hypertensive effects in SHR animal model. BSP significantly induced HO-1 expression both at transcriptional and protein levels in a time- and dose-dependent manner as measured by RT-PCR and Western blot analysis, respectively. These inductions were abolished by pretreatment of N-acetyl-cystein (NAC, 1~10 mM), but not by employing Tempol, a superoxide dismutase (SOD) mimetic (1~5 mM). As expected, enzymatic activity (~2 fold) determined by bilirubin formation assay and cGMP concentration (~6 fold) were significantly increased in BSP-treated cells. Based on the numerous evidences on the beneficial effects of HO-1 and our results, we investigated in vivo effects of BSP on the antihypertensive activity. The administration of BSP (1% in drinking water) significantly decreased mean blood pressure (BP) (from $218.6{\pm}6.99$ to $190.0{\pm}3.42$ mm Hg, p<0.01). This result indicates that BSP is strong inducer of HO-1 expression, which may be triggered by oxidative stress, and has anti-hypertensive activity.

• Archives of Pharmacal Research
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• 제29권5호
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• pp.375-383
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• 2006

The anti platelet effects of a novel guanidine derivative, KR-32570 ([5-(2-methoxy-5-chlorophenyl) furan-2-ylcarbonyl]guanidine), were investigated with an emphasis on the mechanisms underlying its inhibition of collagen-induced platelet aggregation. KR-32570 significantly inhibited the aggregation of washed rabbit platelets induced by collagen $(10{\mu}g/mL)$, thrombin (0.05 U/mL), arachidonic acid $(100{\mu}M)$, a thromboxane (TX) $A_2$ mimetic agent U46619 (9,11-dideoxy-9,11-methanoepoxy-prostaglandin $F_2,\;1{\mu}M$) and a $Ca^{2+}$ ATPase inhibitor thapsigargin $(0.5{\mu}M)$ ($IC_{50}$ values: $13.8{\pm}1.8,\;26.3{\pm}1.2,\;8.5{\pm}0.9,\;4.3{\pm}1.7\;and\;49.8{\pm}1.4{\mu}M$, respectively). KR-32570 inhibited the collagen-induced liberation of $[^3H]$arachidonic acid from the platelets in a concentration dependent manner with complete inhibition being observed at $50{\mu}M$. The $TXA_2$ synthase assay showed that KR-32570 also inhibited the conversion of the substrate $PGH_2$ to $TXB_2$ at all concentrations. Furthermore, KR-32570 significantly inhibited the $[Ca^{2+}]_i$ mobilization induced by collagen at $50{\mu}M$, which is the concentration that completely inhibits platelet aggregation. KR-32570 also decreased the level of collagen $(10{\mu}g/mL)$induced secretion of serotonin from the dense-granule contents of platelets, and inhibited the NHE-1-mediated rabbit platelet swelling induced by intracellular acidification. These results suggest that the antiplatelet activity of KR-32570 against collagen-induced platelet aggregation is mediated mainly by inhibiting the release of arachidonic acid, $TXA_2$ synthase, the mobilization of cytosolic $Ca^{2+}$ and NHE-1.

• 생명과학회지
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• 제23권11호
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• pp.1342-1350
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• 2013

본 연구는 화학적 허혈에 의해 손상된 마우스 간세포에서 hydrogen sulfide ($H_2S$)의 효과를 규명하기 위해 수행되었다. 본 연구에서 허혈 모방 화합물로 알려져 있는 cobalt chloride ($CoCl_2$)는 간세포 손상을 시간 및 농도 의존적으로 유의성 있게 증가 시켰다. $CoCl_2$에 의한 간세포 손상은 Sodium sulfide (NaHS, $H_2S$ 공여제)의 전처리에 의해 유의적으로 감소 되었다. $CoCl_2$는 세포 내 활성산소(reactive oxygen species, ROS)의 농도를 증가시켰으며, 이는 NaHS 및 N-acetyl-cysteine (NAC, a ROS 제거제)에 의해 감소하였다. 또한, $CoCl_2$에 의해 증가된 p38 MAPK 인산화가 NaHS 및 NAC에 의해 억제되었다. $CoCl_2$에 의해 증가된 Bax/Bcl-2 비율은 NaHS, NAC 및 SB 203580 (p38 MAPK 저해제)에 의해 차단되었으며, $CoCl_2$에 의해 유발된 간세포의 손상 또한 NaHS, NAC 및 SB 203580의 전처리에 의해 억제되었다. NaHS는 $CoCl_2$에 의해 증가된 COX-2의 발현을 억제하였다. 또한, NaHS의 효과와 유사하게 $CoCl_2$에 의해 증가된 COX-2의 발현이 NAC에 의해 억제되었다. 더욱이, NS-398 (COX-2 선택적 억제제)는 $CoCl_2$에 의한 Bax/Bcl-2 비율의 증가를 억제하였을 뿐 아니라, 간세포의 세포 손상 또한 억제하였다. 결론적으로, $H_2S$는 초대배양 된 마우스 간세포에서 $CoCl_2$에 의해 유발된 간세포의 손상을 ROS에 의해 유발된 p38 MAPK 및 COX-2 경로의 활성화를 억제함으로써 세포보호효과를 수행하는 것을 알 수 있었다.

• 한국식품위생안전성학회지
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• 제29권2호
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• pp.85-91
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• 2014

Deoxynivalenol (DON) and related trichothecene mycotoxins are extensively distributed in the cereal-based food and feed stuffs worldwide. Recent climate changes and global grain trade increased chance of exposure to more DON and related toxic metabolites in poorly managed production systems. Monitoring the biological and environmental exposures to the toxins are crucial in protecting human and animals from toxicities of the hazardous contaminants in food or feeds. Exposure biomarkers including urine DON itself are prone to shift to less harmful metabolites by intestinal microbiota and liver metabolic enzymes. De-epoxyfication of DON by gut microbes such as Eubacterium strain BBSH 797 and Eubacterium sp. DSM 11798 leads to more fecal secretion of DOM-1. By contrast, most of plant-derived DON-glucoside is also easily catabolized to free DON by gut microbes, which produces more burden to body. Phase 2 hepatic metabolism also contributes to the glucuronidation of DON, which can be useful urine biomarkers. However, chemical modification could be very typical depending on the anthropologic or genetic background, luminal bacteria, and hepatic metabolic enzyme susceptibility to the toxins in the diet. After toxin exposure, effect biomarkers are also important in estimating the linkage and mechanisms of foodborne diseases in human and animal population. Most prominent adverse effects are demonstrated in the DON-induced immunological and behavioral disorders. For instance, acutely elevated interleukin-8 from insulted gut exposed to dietaty DON is a dominant clinical biomarker in human and animals. Moreover, subchronic exposure to the toxins is associated with high levels of serum IgA, a biological mediator of IgA nephritis. In particular, anorexia monitoring using mouse models are recently developed to monitor the biological activities of DON-induced feed refusal. It is also mechanistically linked to alteration of serotoin and peptide YY, which are promising biomarkers of neurological disorders by the toxins. As animal-alternative biomonitoring, huamn enterocyte-based assay has been developed and more realistic gut mimetic models would be useful in monitoring the effect biomarkers in resposne to toxic contaminants in the future investigations.