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        검색결과 23

        1.
        2023.10 구독 인증기관·개인회원 무료
        Honey bees are crucial pollinators for agricultural and natural ecosystems, but are experiencing heavy mortality in Korea due to a complex suite of factors. Extreme winter losses of honey bee colonies are a major threat to beekeeping but the combinations of factors underlying colony loss remain debatable. Finding solutions involves knowing the factors associated with high loss rates. To investigate whether loss rates are related to Varroa control and climate condition, we surveyed beekeepers in korea after wintering (2021–2022 to 2022–2023). The results show an average colony loss rate of 46%(2022) and 17%(2023), but over 40% colony loss before wintering at 2022. Beekeepers attempt to manage their honey bee colonies in ways that optimize colony health. Disentangling the impact of management from other variables affecting colony health is complicated by the diversity of practices used and difficulties handling typically complex and incomplete observational datasets. We propose a method to 1) Varroa mite population Control by several methods , and 2) Many nursing bee put in hive before wintering.
        2.
        2022.12 구독 인증기관·개인회원 무료
        4.
        2022.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Foot-and-mouth disease (FMD) is a highly contagious vesicular disease that affects cloven-hoofed animals, causing substantial economic losses to the livestock industry. The causative FMD virus (FMDV) comprises four structural proteins (VP1, VP2, VP3, and VP4) and several non-structural proteins. Among the capsid proteins, VP4 is the most conserved, making it an attractive target as a diagnostic and vaccine antigen, regardless of FMDV serotype. In this study, we attempted to express the VP4 protein N-terminally fused to a glutathione S-transferase (GST) tag in Escherichia coli. Whereas VP0 and VP2 proteins were expressed in the soluble fraction, we failed to detect VP4, even in the insoluble fraction. To investigate the effect of VP4 C-terminal amino acid residues on protein expression, we constructed three VP4 mutants fused to GST, among which the mutant in which the C-terminal 15 amino acid residues had been deleted showed the highest level of protein expression. Furthermore, protein expression was observed even in the mutant in which three amino acid residues (DKK) had been fused to the C terminus. However, unlike the other two mutants, the wild-type VP4 mutant was poorly expressed, thereby indicating that the C-terminal amino acid residues could play a pivotal role in determining expression of the VP4 protein in E. coli.
        4,000원
        7.
        2021.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구의 목적은 암석 판별 탐구에서 중학교 영재학생들의 과학적 관찰과 추론의 특징을 탐색하기 위함이었다. 이를 위하여 영재교육원에 다니는 19명의 중학교 1학년 학생들에게 과학 교과서에서 중요하게 다루는 화성암, 변성암, 퇴적암이 포함된 5가지 암석 샘플을 나누어 주고 각 암석의 형성과정, 종류, 이름 등을 유추해 보도록 하였다. 연구 결과, 학생들이 주로 주목하는 암석의 특징은 색, 조직, 구조로 나타났다. 전형적인 암석의 경우 기억에 의존하여 즉각적으로 암석 판별에 성공하나 관찰에 근거한 유의미한 추론이 이루어지지 못하는 반면, 판별에 어려움을 겪는 암석의 경우 관찰에 근거한 유의미한 추론 과정이 담화를 통해 드러나기도 하였다. 또한 유의미한 관찰 결과로부터 과학적 추론 을 타당하게 구성하였으나 암석 판별에 실패한 경우도 나타났다. 본 연구 결과는 중학생들의 암석 판별 탐구 활동에서 학생들의 현 수준을 파악하고, 학교 현장에서 이루어지는 암석 판별 탐구가 학생들에게 과학적 관찰과 추론의 경험을 제공할 수 있도록 방안을 모색하고, 시사점을 제공하고자 한다.
        4,900원
        11.
        2013.09 구독 인증기관 무료, 개인회원 유료
        Transgenic chickens have been spotlighted as an highly potent bioreactor for their fecundity, short generation time, and eggs associated with mass production of protein. In this study, we generated transgenic chickens exhibiting oviduct specific expression of human growth hormone fused to human transferrin for oral administration. Gene of the modified growth hormone located at downstream ovalbumin promoter (∼3.6 kb) was introduced to stage X blastodermal cell employing retrovirus vector system. Several transgenic chickens were successfully generated. However, genomic analyses showed unexpected deletion within the transgene. The modification of the transgene seemed to occur during germ cell formation because the deletion was detected only from the sperm DNA of the G0 founder animal. There was no evidence of deletion in the somatic cell DNA samples of the same chicken. Consequently, same pattern of the deletion was confirmed in both somatic and germ cells of the G1 progeny.
        4,000원
        16.
        2008.03 구독 인증기관 무료, 개인회원 유료
        Pronuclear DNA microinjection has been the most universal method in transgenic animal production but its success rate of transgenesis in mammals are extremely low. To address this long-standing problem, we used retrovirus- and lentivirus-based vectors carrying the enhanced green fluorescent protein (EGFP) gene under the control of ubiquitously active cytomegalovirus (CMV) promoter to deliver transgenes to bovine embryos. The rate of transgenesis was evaluated by counting EGFP positive blastocysts after injection of concentrated virus stock into the perivitelline space of the bovine oocytes in metaphase II. Among two different types of lentivirus vectors derived from FIV (feline immunodeficiency virus) and HIV (human immunodeficiency virus), the former scored the higher gene transfer efficiency; almost 100% of the blastocysts developed from the oocytes infected with FIV-based vector were EGFP positive. As for the vectors derived Com HIV lentivirus, the transgenesis rate of the blastocysts was reduced to 39%.
        4,900원
        18.
        2006.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        It has been reported that light-emitting diodes(LED) can be used in the treatment of oral diseases. Although bio-stimulatory effects of LED irradiation such as promotes stimulation of wound healing have been well known, there are few reports about molecular mechanism associated with cell cycle by LED irradiation. The purpose of present study was to examine the molecular event in cell cycle of LED irradiation on primary human gingival fibroblast(hGF) in vitro. The source of light for irradiation was a continuous-wave LED emitting at a wavelength of 635nm, and manufactured that energy density was 5mW/cm2 on sample surface. The hGF were irradiated for 1 hour at 37℃ in 5% CO2 humidified chamber. Experimental samples were acquired at 0 (right after irradiation), 8 and 24 hour after irradiation. To investigate the molecular mechanisms associated with cell cycle, growth phase was determined by flow cytometry and mRNA expression of cyclin A, cyclin B, cyclin D1, cyclin E, cdc2, PCNA, p18, p27, p21, and p53 were determined by real time RT-PCR. Flow cytometric analysis demonstrated the percentage of cells in the G1 and S phase were decreased, but the G2 phase increased, which showed cells irradiated by LED were transitioned from S to G2 phase. For mRNA expression, cyclin B, cdc2, PCNA and p53 were increased at 0 hour after irradiation, and most of cell cycle molecules were increased at 8 hour after irradiation. At 24 hour after irradiation, cyclin A, cyclin E, PCNA and p18 were increased. Taken together, LED irradiation induced proliferation of hGF cells through transition from S to G2 phase.
        4,000원
        19.
        2005.10 KCI 등재 구독 인증기관·개인회원 무료
        The purpose 01' pl'esent study was to examine the molecular events in apoptosis by CoCl2, mimicking hypoxic cond ition and recovering effects by LED ir l'adiation on Human SH-SY5Y neuroblastoma cells The SOUl'ce 0 1' light for ir l'adiation was a continuous-wave LED emitting at a wavelenl양h of 590 nm, and manufactured that ene rgy density was 5 mW!cm2 on sample surface, After ir l'adiation, cell viabi lity was measured with BrdU , cell morphol ogy was examined with Diff- Quik staining, cell signaling was monitored with various apoptosis-related molecules using RNase Pl'otection Assay(RPA) , W11en treated with CoC12, apoptotic induction was found in the SH-SY5Y cells in a concentration-dependent and time-dependent manner , Diff-Quik s taining was revealed that DNA fragmentation re presented apoptosis was examined in CoC12-tl'eated group, Moreover, RPA assay of SH-SY5Y cclls lIs ing val'iolls apoptosis-related molecllles showed that the apoptotic cell population was mcreased J-loweve. there was sorne signifïcant change in LED irradiatied cells aftel' treatement of CoC12 The main mechanism for Lhese a poptosis appearecl to be mito c hondriεt - m ecliated pathway, such as cytochrome- c‘ caspase-9, caspase-3, pro-apototic protein ßax, anti-apototic protein Bcl-2, and death receptor• mediated pathway, such as Fas, cas pase- 8, a ncl TNFRl These results demonstrate that CoCI2 induce apoptosis in SH-SY5Y via different dual apop tosis pathway through death receptor pathway as well as mitochondria- dependent pathway and LED irradiation can recl llces the CoCl2-induced apoptosis by blocking their internal signaling pathway
        20.
        1995.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        내부산의 탈거제로 탄산나트륨을 함유하는 유화액막의 거동을 묘사하기 위하여 수학적 모델이 제시되었다. 젖산의 회분식 추출 실험 결과가 모델의 계산 결과와 비교되었는데, 모델의 계산 결과는 담체농도, 탈거제농도, 교반속도, 처리비와 같은 변수의 영향을 잘 예측할 수 있었다. 유화액막의 주요 문제 중의 하나인 에멀젼의 팽윤을 줄이기 위하여, 액체 파라핀, n-데칸올, 사이클로헥사논, 스판-85 같은 막 첨가제가 사용되었다. 사용된 모든 첨가제는 팽윤 정도를 줄이는데 어느 정도 효과가 있었다. 사이클로헥사논은 팽윤을 줄일 뿐만 아니라, 젖산의 전달 속도를 크게 증가시키는 것으로 관찰되었다.
        4,600원
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