• Journal of Plant Biology
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• 제14권2호
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• pp.7-10
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• 1971

Haploid cell obta-ined from microspores of Solanum nigrum were cultured on two kinds of medium, "Callus-inducing medium" and "Differentiation medium", in order to conduct histological studies of callus and examine differentiation of plantlets. On the callus-inducing medium the calli grew rapidly. The bulk of callus mass was light brown colored "Wet callus" covered on the surface with thin layers of rough and gleaming "White callus". The wet callus was consisted of parenchyma and meristematic tissues, while the white callus had no meristematic tissues. Large parenchyma cells, by successive divisions, became multicellular or poly nucleate cells which developed later to be meristematic tissues. The calli embedded on the differentiation medium quickly turned to dark brown color. Plantlets, however, came out later from these blackened callus mass. In the callus sectioned about ten weeks after imbedding on the differentiation medium, radially elongated tissue, concentric tissue, epidermis, tracheid-like structure, and plant jprimordia were observed.ure, and plant jprimordia were observed.

• 한국도서관정보학회지
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• 제33권2호
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• pp.235-258
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• 2002

최초의 웹 페이지가 인터넷 상에 올려진 1991년 이래, 인터넷 상의 무수한 웹 사이트 정보검색은 전통적 색인작성 방법과는 상이한 새로운 방법을 개발하고 있다. 본고는 새롭게 발전하는 웹 색인작성에 관한 기초연구로서, 그의 기초가 되는 삽입색인을 살펴보고, 웹 사이트의 정보제공을 위해 필수적인 메타 태그와 웹 색인을 위한 그들의 작성방법을 검토하고, 웹 색인작성에 관한 주요사항을 비교적 상세하게 연구검토하였다.

• 대한임베디드공학회논문지
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• 제10권1호
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• pp.7-12
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• 2015

As smart phone became popular, its excessive uses cause adverse effects called smart-phone syndrome such as Turtle-neck syndrome in physical side and smart-phone addiction in mental aspects. Turtle-neck syndrome incurred by incorrect posture when you watch smart-phone, which causes a serious health problems. However, these syndromes can be detected by gyro-sensor and timer, and prevented by correcting the posture and halting the function with smart-phone application (App). Thus, this paper proposes App that helps user to realize bad posture and addiction to smart-phone, and to acquire the correct habit by inducing user to stretch neck or to stop operation with warning message. If we tried to adjust bad posture and addiction in using smart-phone through this application, the social losses from smart-phone syndrome would be minimized as a result.

• 한국지진공학회논문집
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• 제21권1호
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• pp.69-76
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• 2017

Seismic analyses of a pile under a large rigid basement foundation embedded in the homogeneous soil layer were performed practically by a response displacement method assuming a sinusoidal wave form. However, it is hard to take into account the characteristics of a large mat foundation and a heterogeneous soil layer with the response displacement method. The response displacement method is relevant to the 2D problems for longitudinal structures such as tunnel, underground cave structure, etc., but might not be relevant with isolated foundations for building structures. In this study, seismic pile analysis by a pseudo 3D finite element method was carried out to compare numerical results with results of the response displacement method considering 3D characteristics of a foundation-soil system which is important for the building foundation analyses. Study results show that seismic analyses results of a response displacement method are similar to those of a pseudo 3D numerical method for stiff and dense soil layers, but they are too conservative for a soft soil layer inducing large soil pressures on the foundation wall and large pile displacements due to ignored foundation rigidity and resistance.

• International Journal of Railway
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• 제6권3호
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• pp.107-111
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• 2013

In order to constrain the railway roadbed settlement which causes track irregularity, and thus threats running stability and ride quality, advanced Back-to-Back (BTB) reinforced retaining wall was numerically analyzed as railway roadbed structure. This study is intended to improve conventional Back-to-Back reinforced retaining wall as the technology which would reduce the roadbed settlement in a way of constraining the lateral displacement of its prestressed vertical facing and inducing arching effects in roadbed (backfill) placed between masonry diaphragm wall and vertical facing. As a result of numerical analysis, it was found that the roadbed settlement was reduced by 10% due to the prestressed vertical facing and embedded masonry diaphragm wall of the advanced Back-to-Back reinforced retaining wall system.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2008년도 춘계 학술발표회 제20권1호
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• pp.1069-1072
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• 2008

매립된 철근의 부식이 진행될 경우, 부착강도 및 강성이 감소되며, 구조물의 열화가 발생하여 사용 수명이 단축된다. 이러한 문제를 해결하기 위하여 RC 부재의 부착특성에 대한 평가가 인위적으로 철근을 빠르게 부식시키는 방법을 통하여 지금까지 연구되어왔다. 그러나, 이러한 인위적인 부식방법은 실제 부식 상황과 일치하지 않으며, 결과적으로 실제 상황에서의 RC 부재에 대한 부식 가능성을 과대평가할 수 있다. 따라서, 본 연구는 인위적인 방법과 자연적인 방법에 의해 RC 부재를 부식시킴으로써 부착 강성의 차이를 평가하고자 하였다. 자연적인 부식의 경우, 부식면적 50%에서 취성파괴가 발생했으며, 부식면적 80%이상에서는 부착강도가 약 10%이상 감소하였다. 특히, 자연적 부식의 경우 낮은 부식수준에서 콘크리트의 열화가 발생하였다. 따라서 향후 부식에 따른 부재의 성능저하를 평가하고자 할 경우에는 인위적으로 부식시킨 시험체로부터 평가하는 것은 곤란하며 반드시 자연적으로 부식시킨 시험체를 사용하여 성능을 평가해야 한다고 판단된다.

• 한국건축시공학회지
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• 제22권2호
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• pp.149-160
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• 2022

본 연구에서는 국내에서 생산되는 목재와 접착제를 활용한 Glued-in rod 접합부의 인발성능을 평가하고자 접착제의 종류, 철근의 매입깊이 및 매입방향을 고려한 인발성능 실험연구를 수행하였다. 실험결과, 액상형 접착제 사용 실험체가 더 우수한 인발성능을 보여주었으며, 철근의 매입깊이가 길어질수록 철근의 항복을 먼저 유도하여 높은 최대 인발하중을 보여주었다. 인발성능 실험결과를 통하여 철근의 항복강도보다 접착제의 부착강도를 더 강하게 설계하는 것이 유리한 Glued-in rod 접합부 설계식을 제안하였으며, 접착제의 부착강도의 시공오차를 고려한 보정계수 0.75 또한 제안하였다.

• Bulletin of the Korean Chemical Society
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• 제35권9호
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• pp.2774-2780
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• 2014

A dynamics study of relaxation and fragmentation of icosahedral argon cluster with a vibrationally excited $Ar_2^+$ (${\nu}$) is presented. Local translation is shown to be responsible for inducing energy flow from the embedded ion to host atoms and fragmentation of the cluster consisting of various low frequency modes. The total potential energy of $(Ar_2^+)Ar_{12}$ is formulated using a building-up procedure of host-guest and host-host interactions. The time dependence of ion-to-host energy transfer is found to be tri-exponential, with the short-time process of ~100 ps contributing most to the overall relaxation process. Relaxation timescales are weakly dependent on both temperature (50-300 K) and initial vibrational excitation (${\nu}$ = 1-4). Nearly 27% of host atoms in the cluster with $Ar_2^+$ (${\nu}$ = 1) fragment immediately after energy flow, the extent increasing to ~43% for ${\nu}$ = 4. The distribution of fragmentation products of $(Ar_2^+)Ar_{12}{\rightarrow}(Ar_2^+)Ar_n+(12-n)Ar$ are peaked around $(Ar_2^+)Ar_8$. The distribution of dissociation times reveals fragmentation from one hemisphere dominates that from the other. This effect is attributed to the initial fragmentation causing a sequential perturbation of adjacent atoms on the same icosahedral five-atom layer.

• BMB Reports
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• 제43권4호
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• pp.279-283
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• 2010

Polydnavirus genome is segmented and dispersed on host wasp chromosome. After replication, the segments form double- stranded circular DNAs and embedded in viral coat proteins. These viral particles are delivered into a parasitized host along with parasitoid eggs. A serine-rich protein (SRP) is predicted in a polydnavirus, Cotesia plutellae bracovirus (CpBV), genome in its segment no. 33 (CpBV-S33), creating CpBV-SRP1. This study explored its expression and physiological function in the diamondback moth, Plutella xylostella, larvae parasitized by C. plutellae. CpBV-SRP1 encodes 122 amino acids with 26 serines and several predicted phosphorylation sites. It is persistently expressed in all tested tissues of parasitized P. xylostella including hemocyte, fat body, and gut. Its physiological function was analyzed by injecting CpBV-S33 and inducing its expression in nonparasitized P. xylostella by a technique called SERI (segment expression and RNA interference). The expression of CpBV-SRP1 significantly impaired the spreading behavior and total cell count of hemocytes of treated larvae. Subsequent RNA interference of CpBV-SRP1 rescued the immunosuppressive response. This study reports the persistent expression of CpBV-SRP1 in a parasitized host and its parasitic role in suppressing the host immune response by altering hemocyte behavior and survival.

• 대한약침학회지
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• 제18권4호
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• pp.20-25
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• 2015

Objectives: Recently, thread-embedding therapy (TET) has been widely applied in Korean medicine for cosmetic purposes such as reducing skin wrinkles. An inserted thread was reported to have induced continuous stimulation, followed by support for connective tissue regeneration. However, the potential role of TET in hair-growth has not yet been reported. Methods: We designed this study to evaluate whether TET has a hair-growth-promoting effect. C57 black 6 (C57BL/6) mice were divided into three groups: normal saline-treated, minoxidil-treated, and thread-embedded groups. Normal saline or 5% minoxidil was topically sprayed on the dorsal skin of the mice once a day for 16 days. Medical threads were embedded into the dorsal skin of the mice in a single application. Hair growth activity was evaluated by using dermoscopic and microscopic observations. Sections of the dorsal skin were stained with hematoxylin and eosin. Expressions of bromodeoxyuridine (BrdU), proliferating cell nuclear antigen (PCNA), fibroblast growth factor-7 (FGF-7), and fibroblast growth factor-5 (FGF-5) were detected by using immunohistochemical staining. A reverse transcription-polymerase chain reaction (RT-PCR) analysis was adopted to measure the messenger RNA (mRNA) expressions of FGF-7 and FGF-5. Results: TET enhanced anagen development in the hair follicles of C57BL/6 mice. The expressions of BrdU and PCNA, both of which imply active cellular proliferation, were increased by using TET. Moreover, TET increased the expression of FGF-7, an anagen-inducing growth factor, while decreasing the expression of FGF-5, an anagen-cessation growth factor, both at the protein and the mRNA levels. Conclusion: TET enhanced hair re-growth in C57BL/6 mice. TET regulated the expressions of anagen-associated growth factors and activated the proliferation of hair follicular cells in depilated skin lesions. Considering its long-lasting effect, TET may be a good alternative therapeutic for the treatment of alopecia.