• BMB Reports
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• 제56권9호
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• pp.520-525
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• 2023

Alzheimer's disease (AD) is a progressive neurodegenerative disease characterized by cognitive decline. Several recent studies demonstrated that impaired adult neurogenesis could contribute to AD-related cognitive impairment. Adult subventricular zone (SVZ) neurogenesis, which occurs in the lateral ventricles, plays a crucial role in structural plasticity and neural circuit maintenance. Alterations in adult SVZ neurogenesis are early events in AD, and impaired adult neurogenesis is influenced by the accumulation of intracellular Aβ. Although Aβ-overexpressing transgenic 5XFAD mice are an AD animal model well representative of Aβ-related pathologies in the brain, the characterization of altered adult SVZ neurogenesis following AD progression in 5XFAD mice has not been thoroughly examined. Therefore, we validated the characterization of adult SVZ neurogenesis changes with AD progression in 2-, 4-, 8-, and 11-monthold male 5XFAD mice. We first investigated the Aβ accumulation in the SVZ using the 4G8 antibody. We observed intracellular Aβ accumulation in the SVZ of 2-month-old 5XFAD mice. In addition, 5XFAD mice exhibited significantly increased Aβ deposition in the SVZ with age. Next, we performed a histological analysis to investigate changes in various phases of adult neurogenesis, such as quiescence, proliferation, and differentiation, in SVZ. Compared to age-matched wild-type (WT) mice, quiescent neural stem cells were reduced in 5XFAD mice from 2-11 months of age. Moreover, proliferative neural stem cells were decreased in 5XFAD mice from 2 to 8 months of age. Furthermore, differentiations of neuroblasts were diminished in 5XFAD mice from 2-11 months of age. Intriguingly, we found that adult SVZ neurogenesis was reduced with aging in healthy mice. Taken together, our results revealed that impairment of adult SVZ neurogenesis appears with aging or AD progression.

• Journal of applied mathematics & informatics
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• 제18권1_2호
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• pp.311-320
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• 2005

Studies in the evolutionary biology of aging require good estimates of the age-dependent mortality rate coefficient (one of the Gompertz parameters). In this paper we introduce an alternative algorithm for estimating this parameter. And we discuss the sensitivity of the estimates to changes in the other model parameters.

• 대한화학회지
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• 제37권12호
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• pp.1068-1075
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• 1993

토마토(Lycopersicum esculentum)를 파종하여 1년간 성장시키면서 성장기간에 따른 잎과 뿌리의 catalase 활성 변화를 측정하였다. 뿌리에 있어서의 catalase 활성은 잎의 경우에 비해 전반적으로 매우 미약하였다. 반면에 잎의 catalase 활성은 매우 현저한 변화 양상을 나타냈는데 주로 peroxisomal 분획에 존재하였고 특히 발아 후 2주 이내의 발아초기에 76 ${\mu}mol$/ml/min의 최고 활성은 기점으로 하여 급격히 감소했다가 성장기 4 ∼ 5 개월에 즈음하여 상당히 증가된 활성을 보였으며 11 ∼ 12개월째 노화기에 가장 저조한 활성을 보였다. 이와 같이 성장시기에 따라서 변화하는 catalase 활성에 영향을 미치는 인자로서 첫째 발아기에는 glyoxylate cycle과 $\beta$-oxidation이 일어나는 glyoxisomal 반응 그리고 둘째 발아기 이후에는 광합성 반응이 각각 해당시기에 $H_2O_2$를 발생시키는 반응으로 작용할 것으로 간주된다. 이 외에도 NADPH는 불활성화된 catalase(compound II)를 다시 활성화시켜 해로운 기질인 $H_2O_2$로부터 catalase 보호제로서의 역할을 함으로써 토마토의 생장기간 전체에 걸쳐 작용하는 것으로 나타났다.

• 가정과삶의질연구
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• 제19권6호
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• pp.145-155
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• 2001

The purposes of this study were first to construct statistical and econometric models based on Amemiya\`s Type I Tobit mainly addressing the issue of statistical efficiency; second to explore income, price, and curvilinear age effects on the explained variable in order to illustrates its statistical marginal effects related to econometric issues; finally to provide invaluable insight for graphical simulations as a new interpretation approach using Tobit analysis. Results indicated that interpretation for the mean marginal effects of three possible cases of dependent variable was more likely to be evident to understand Tobit results compared to conventional analysis only using latent variable, beta. Results also revealed that prediction value of dependent variable can be possibly and easily projected by the independent variable changed whereas only beta value can not illustrate its projection as independent variables'changes.

• Steel and Composite Structures
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• 제18권5호
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• pp.1239-1258
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• 2015

This paper presents a master-slave constraint method, which may substitute the conventional transformed-section method, to account for the changes in cross-sectional properties of composite members during construction and to investigate the time-dependent performance of steel-concrete composite bridges. The time-dependent effects caused by creep and shrinkage of concrete are considered by combining the age-adjusted effective modulus method and finite element analysis. An efficient computational tool which runs in AutoCAD environment is developed to simulate the construction process of steel-concrete composite bridges. The major highlight of the developed tool consists in a very convenient and user-friendly interface integrated in AutoCAD environment. The accuracy of the proposed method is verified by comparing its results with those provided by using the transformed-section method. Furthermore, the computational efficiency of the developed tool is demonstrated by applying it to a steel-concrete composite bridge.

• 한국동물학회지
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• 제16권1호
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• pp.43-53
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• 1973

年齡에 따른 미토콘드리아의 構造的變化를 調査하기 위하여 電子顯微鏡을 利用하여 배추흰나비, Pieris rapae L.의 飛筋을 觀察하였다. 미토콘드리아는 크리스타가 잘 발달되지 않은 A型과 크리스타가 복잡하게 발달된 B型의 두種類가 存在하였다. 羽化直後의 것에서는 A型과 B型미토콘드리아가 꼭같이 存在하였고 羽化後 10日 經過한 것에서는 B型미토콘드리아에 比하여 A型이 急速히 減少하였다. 羽化後 10日이 經過된 것의 筋細胞에서는 B型미토콘드리아가 年齡의 增加에 따른 微細構造的變化를 이르켰다. 이러한 老衰된 미토콘드리아의 微細構造的 變化像은 部分的으로 그 內膜이 髓　狀構造를 再形成하는 것으로 나타났는데 이것은 곧 年齡에 따른 退化를 意味한다. 髓　狀構造를 形成하는 것은 많은 同心圓體이며 이 同心圓體의 數와 크기는 年齡과 比例하면서 增加했다. 筋細胞의 細胞質에서 미토콘드리아 內로 侵入한 글리코겐 粒子는 同心圓體의 中央에서도 觀察되었다.

• 한국약용작물학회지
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• 제14권6호
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• pp.329-335
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• 2006

The present study was designed to investigate aging-related effects on the activities of xenobiotic metabolizing enzymes of rat liver by dietary supplementation of Korean red ginseng water-extract. Rat did not show any discernible signs of the rejection symptoms, and blood GOT and GPT levels were not influenced by ginseng water extracts, Cytochrome 450 levels and NADPH cytochrome P45O reductase, p-450 dependent ethoxycoumarin O-deethylase, and benzphetamine N-demethylase activities were decreased with aging, however, these phase I system enzymes activities in the ginseng group of24 months were well maintained compared with normal group. But, Levels of cytochrome bs and NADH-cytochrome b$_5$ reductase activities were also decreased with aging and were not found a clear difference between two groups. Glutathione-s-transferase activity, phase II enzyme system, in liver cytosols was also decreased in old ages, but the degree of decrease was higher in normal group than in giuseng supplemented group. These results indicate that long-term supplementation of red ginseng water extracts from weaning to 24 months do not show any side effects to rats, and retard age-related deteriorations of xenobiotic metabolizing enzymes activities in old ages.

• 가정과삶의질연구
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• 제20권6호
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• pp.37-48
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• 2002

Mid of 1980s witnessed the beginning of a new trend regarding the elderly as the Third Age Group, which is capable of positive selection for their later life. These changes are caused not only by the rising cost of caring them as the dependent to the society, but also by paradigm shift from the clinical and biomedical model to political economy and critical gerontology. The paradigm shift is based on the social constructionism as a perspective on the later life. In this communication the development of social constructionism is reviewed as an approach on the living environment for later life through literature survey. Emphases were made on the anti-ageism instead of ageism in the analysis of the social constructionism perspective for living environment in later life. Individual practice, influencing the practice of others, influencing agency policy, and developing theory were addressed and emphasized for the practice of anti-ageism. This study found the importance of the development of the social constructionism perspective on the study and practice regarding living environment for ‘the Third Age’ in Korean situation.

• BMB Reports
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• 제43권10호
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• pp.649-655
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• 2010

Alzheimer's disease (AD) is the most common age-dependent neurodegenerative disorder and shows progressive memory loss and cognitive decline. Intraneuronal filaments composed of aggregated hyperphosphorylated tau protein, called neurofibrillary tangles, along with extracellular accumulations of amyloid $\beta$ protein (A$\beta$), called senile plaques, are known to be the neuropathological hallmarks of AD. In light of recent studies, epigenetic modification has emerged as one of the pathogenic mechanisms of AD. Epigenetic changes encompass an array of molecular modifications to both DNA and chromatin, including transcription factors and cofactors. In this review, we summarize how DNA methylation and changes to DNA chromatin packaging by post-translational histone modification are involved in AD. In addition, we describe the role of SIRTs, histone deacetylases, and the effect of SIRT-modulating drugs on AD. Lastly, we discuss how amyloid precursor protein (APP) intracellular domain (AICD) regulates neuronal transcription. Our understanding of the epigenomes and transcriptomes of AD may warrant future identification of novel biological markers and beneficial therapeutic targets for AD.

• 대한치과교정학회지
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• 제50권4호
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• pp.249-257
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• 2020

Objective: To evaluate the changes in the nose in three dimensions after Le Fort I osteotomy in patients with skeletal Class III malocclusion. Methods: The subjects were 40 adult patients (20 females and 20 males; mean age, 20.3 ± 3.0 years; range, 17.0 to 31.1 years) who underwent one-piece Le Fort I osteotomy with maxillary advancement and impaction treatment for maxillary hypoplasia. The mean maxillary advancement was 4.56 ± 1.34 mm, and the mean maxillary impaction was 2.03 ± 1.04 mm. Stereophotogrammetry was used to acquire three-dimensional images before and at least 6 months after surgery. Results: Alare (Al) and alare curvature (Ac) points had moved vertically and anterolaterally postoperatively. A significant increase was observed in the nasal ala width and alar base width, and no changes were noted in the columellar length, nasolabial angle, and nasal area. There was a significant relationship between maxillary impaction and nasal ala width and horizontal and sagittal positions of the bilateral Al and Ac. The only relationship found was between maxillary advancement and postoperative sagittal location of the subnasale and pronasale. Conclusions: Nasal soft tissues were highly affected by the vertical movement of the maxilla; however, the soft tissue responses were individual-dependent.