• Bulletin of the Korean Chemical Society
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• 제20권3호
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• pp.355-361
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• 1999

To improve the volatility and stability of lead complexes, the principle of stabilization by saturating the metal coordination sphere by intramolecular coordination through a β-diketonates with an ethereal group has was tested. Several new lead complexes with alkoxyalkyl-substituted β-diketonates, Pb(R1C(O)CHC(O)(CH2)3OR2)2(Rl=t-Bu, Me, OMe, i-Pr, R2=Me, Et), or carboxylate, Pb(OC(O)(CH2)3OEt)2, were prepared by the reaction between Pb(OAc)2 and corresponding alkoxyalkyl-substituted β-diketonates, and they were found to have a viscous liquid phase. The nature of the head (β-diketonate or carboxylate) or tails and substituents of β-diketonates appeared not to be important for the formation of the liquid phase. It is worth mentioning that Pb(OAc)2, which has limited use due to its low solubility, was successfully adopted as a starting material for the preparation of new lead complexes. Easy hydrolysis, reaction with HCl, and 13C NMR spectra indicated that tail portions were not coordinated to the metal as a copper derivative, Cu(t-BuC(O)CHC(O)(CH2)3OMe)2. All these complexes were not volatile enough for the MOCVD experiments, but a methyl derivative, Pb(MeC(O)CHC(O)(CH2)3OEt)2, showed some sublimation. The methoxy derivative, Pb(MeOC(O)CHC(O)(CH2)3OEt)2, was thermally unstable due to possible equilibrium between species coordinating with a keto oxygen atom and an ethereal atom of a methoxy group, which was confirmed by IR and 13C NMR spectra.

• Animal Systematics, Evolution and Diversity
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• 제37권3호
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• pp.205-211
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• 2021

This study investigates the morphological and skull characteristics of the Siberian weasel Mustela sibirica quelpartis from the Jeju Island, South Korea. A total of 26 roadkill specimens (22 males and 4 females) were collected from October 2012 to April 2016. All collected specimens were examined for morphological characteristics, but only 19 specimens (16 males and 3 females) were in a good enough condition to process for skull measurements. This study showed no significant differences in ear length between male and female (p>0.05), and significant differences were found in head-body length, tail length (TL), and hind-food length (p<0.05). Both the male and female of M. s. quelpartis were larger in its external characteristics except for TL than M. s. coreanus living in the mainland of South Korea. M. s. quelpartis males have a smaller skull size than their female counterparts. In general, both male and female M. s. quelpartis showed external characteristics in line with the Island Rule. The findings of this study are important in order to shed more light on the evolutionary mechanism of small mammals living on the Jeju Island.

• ETRI Journal
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• 제42권6호
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• pp.859-871
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• 2020

A spectrally encapsulated (SE) orthogonal frequency-division multiplexing (OFDM) precoding scheme for wireless short packet transmission, which can suppress the out-of-band emission (OoBE) while maintaining the advantage of the cyclic prefix (CP)-OFDM, is proposed. The SE-OFDM symbol consists of a prefix, an inverse fast Fourier transform (IFFT) symbol, and a suffix generated by the head, center, and tail matrices, respectively. The prefix and suffix play the roles of a guard interval and suppress the OoBE, and the IFFT symbol has the same size as the discrete Fourier transform symbol in the CP-OFDM symbol and serves as an information field. Specifically, as the center matrix generating the IFFT symbol is orthogonal, data and pilot symbols can be allocated to any subcarrier without distinction. Even if the proposed precoder is required to generate OFDM symbols with spectral efficiency in the transmitter, a corresponding decoder is not required in the receiver. The proposed scheme is compared with CP-OFDM in terms of spectrum, OoBE, and bit-error rate.

• Biomolecules & Therapeutics
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• 제30권4호
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• pp.334-339
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• 2022

Peroxiredoxin 6 (PRDX6) is a bifunctional protein with both glutathione peroxidase and calcium-independent phospholipase activity. Recently, we reported that PRDX6 plays an important role in dopaminergic neurodegeneration in Parkinson's disease. However, the relationship between PRDX6 function and emotional behavior remains elusive. In the present study, we examined depression- and anxiety-like behaviors in PRDX6-overexpressing transgenic (PRDX6-Tg) mice using the forced swim test, tail suspension test, open field paradigm, and elevated plus-maze. PRDX6-Tg mice exhibited depression-like behaviors and low anxiety. In particular, female PRDX6-Tg mice exhibited anxiolytic behavior in the open field test. Furthermore, the serotonin content in the cortex and 5-hydroxytryptophan-induced head twitch response were both reduced in PRDX6-Tg mice. Interestingly, levels of dopa decarboxylase expression in the cortex were decreased in male PRDX6-Tg mice but not in female mice. Our findings provide novel insights into the role of PRDX6 in 5-HT synthesis and suggest that PRDX6 overexpression can induce depression-like behaviors via downregulation of the serotonergic neuronal system.

• 환경생물
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• 제40권4호
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• pp.579-590
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• 2022

Three free-living marine nematodes(Desmoscolex(Desmoscolex) max Timm, 1970, Daptonema longiapophysis Huang and Zhang, 2010, and Pseudosteineria sinica Huang and Li, 2010) were newly recorded in Korea. Desmoscolex (D.) max was found from subtidal coarse sediment around Wangdolcho in the East Sea. It was characterized by the presence of untypical setae arrangement, obviously elongated triangle-shaped head, long hairy cephalic setae, a long naked tail spinneret, and the absence of peduncle at the base of somatic setae. Daptonema longiapophysis was obtained from intertidal sandy sediments in the southern coast of Korea. It was characterized by the presence of setiform labial sensilla, spicules with a projection on both sides, and gubernaculum with dorso-caudal apophysis. Pseudosteineria sinica was discovered from the intertidal sediment in the Yellow Sea. It was characterized by unobservable amphideal fovea, different lengths of spicules, and gubernaculum with dorso-caudal apophysis. In this study, we provide detailed morphological features of three free-living marine nematodes by differential interference contrast microscopy.

• Molecules and Cells
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• 제45권3호
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• pp.158-167
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• 2022

Ubiquitin (Ub) is post-translationally modified by Ub itself or Ub-like proteins, phosphorylation, and acetylation, among others, which elicits a variety of Ub topologies and cellular functions. However, N-terminal (Nt) modifications of Ub remain unknown, except the linear head-to-tail ubiquitylation via Nt-Met. Here, using the yeast Saccharomyces cerevisiae and an Nt-arginylated Ub-specific antibody, we found that the detectable level of Ub undergoes Nt-Met excision, Nt-deamination, and Nt-arginylation. The resulting Nt-arginylated Ub and its conjugated proteins are upregulated in the stationary-growth phase or by oxidative stress. We further proved the existence of Nt-arginylated Ub in vivo and identified Nt-arginylated Ub-protein conjugates using stable isotope labeling by amino acids in cell culture (SILAC)-based tandem mass spectrometry. In silico structural modeling of Nt-arginylated Ub predicted that Nt-Arg flexibly protrudes from the surface of the Ub, thereby most likely providing a docking site for the factors that recognize it. Collectively, these results reveal unprecedented Nt-arginylated Ub and the pathway by which it is produced, which greatly expands the known complexity of the Ub code.

• 한국식품저장유통학회지
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• 제30권1호
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• pp.42-51
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• 2023

This study aimed to characterize a lytic Salmonella Typhimurium-specific (ST) phage and its biofilm control capability against S. Typhimurium biofilm on polypropylene surface. ST phage was isolated, propagated, and purified from water used in a slaughterhouse. The morphology of ST phage was observed via transmission electron microscopy. Its bactericidal effect was evaluated by determining bacterial concentrations after the phage treatment at various multiplicities of infection (MOIs) of 0.01, 1.0, and 100. Once the biofilm was formed on the polypropylene tube after incubation at 37℃ for 48 h, the phage was treated and its antibiofilm capability was determined using crystal violet staining and plate count method. The phage was isolated and purified at a final concentration of ~11 log PFU/mL. It was identified as a myophage with an icosahedral head (~104 nm) and contractile tail (~90-115 nm). ST phage could significantly decrease S. Typhimurium population by ~2.8 log CFU/mL at an MOI of 100. After incubation for 48 h, biofilm formation on polypropylene surface was confirmed with a bacterial population of ~6.9 log CFU/cm². After 1 h treatment with ST phage, the bacterial population in the biofilm was reduced by 2.8 log CFU/cm². Therefore, these results suggest that lytic ST phage as a promising biofilm control agent for eradicating S. Typhimurium biofilm formed on food contact surfaces.

• 대한의생명과학회지
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• 제2권1호
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• pp.57-69
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• 1996

한국산 대륙밭쥐 (Clethrionomys rufocanus regulus) 정자변태 과정을 알아보기 위하여 정소내 세정 관상피의 세포분화에 따른 형태적 특징들을 기초로 하여 전자현미경으로 관찰한 결과는 다음과 같다. 1. 대륙밭쥐의 정자변태 과정은 골지(Golgi), 두모(cap), 첨체(acrosome), 성숙(maturation) 및 이탈기(spermiation phase)로 구분하였고, 다시 각각 전후단계로 세분하여 전과정을 10단계로 나누었다. 2. 염색질 변화는 골지 후기에서 서서히 응축하여 성숙기에서 균질화되고, 이탈기에서 완전한 핵을 형성하였다. 3. 정자두부는 낫꼴모양을 가지며, 정자꼬리는 골지 전기에서 형성되기 시작하여 이탈기에서 완성되었다. 4. 이탈 전 후기의 정자세포의 형태적 특징으로서는, 이탈전기의 정자 세포는 3가지 유형으로 구분 되어졌다. (1).미토콘드리아의 불규칙 배열과 더불어 경부와 중편부에 세포질 소적을 함유한 정자세포(A-type). (2). 미토콘드리아가 축사를 중심으로 완전히 배열되고, 중편부에 세포질 소적을 함유한 정자세포(B-type). (3) 축사를 중심으로 미토콘드리아의 배열 후 경부에만 세포질 소적을 함유한 정자세포(C-type). 그리고 이탈후기의 경우, 정자세포들이 정자두부만 Sertoli cell의 세포질에 싸여져 있거나 또는 Sertoli cell의 세포질로부터 이탈되기 직전의 정자로 구분되었다.

• Parasites, Hosts and Diseases
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• 제26권1호
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• pp.33-38
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• 1988

서울에 있는 미군 병원에서 시행한 신경외과 수술에서 검출 의뢰된 충체를 유극악구충으로 동정하여, 국내에서 충체로 화인된 첫 증례로 보고한다. 환자는 젊은 태국인 여성으로 태국에 체재할 때부터 수막뇌염 증세를 앓았고, 뇌척수액에서는 수많은 호산구를 검출하였다. 등글게 말려서 고정된 충체는 길이가 12.3mm, 폭이 0.9mm이고 앞쪽 끝에 근 head bulb가 있었다. 이 기관의 표피에는 고양이 발톱모양의 피극이 8줄로 배열되어 있었다. 충체 전반부의 표피에는 수많은 피극이 가로로 열지어 있는데 head bulb 가까이 에서는 등근 기저부와 4분지의 끝이 있는 굵은 피극이 분포하나 점차 뒤쪽으로 3분지되고 2분지되면서 가늘고 걸어지는 피극으로 이행되었다. 중간부에서는 짧고 작은 가시모양의 피극이 관찰되고 그 수도 크게 감소하였고 후반부에서는 피극이 관찰되지 않았다. 길이 12.4mm의 식도와 두 개의 식도선(cervical sacs)이 있고, 장이 식도에서 항문까지 곧게 이어져 있었다. 장은 검고 불투명하며, 심하게 굴곡하는 고환과 겁쳐져서 관찰되었다. 뒤 끝에서는 작은 피극이 다시 나타나서 가로로 배열하였고 항문 주위에 Y형으로 피극이 없는 부분이 있었다. 끝의 복면·양쪽에 네 쌍의 큰 감각유두((pedunculated papillae)가 배열하였다. 이상의 소견은 enathostoma spinigerum 성충 수컷의 형태와 일치하였다. 따라서 이 증례는 태국에서 감염되어 국내로 유입된 수막뇌염이 유발된 유극악구충 증례로서, 국내에서는 처음으로 기록되는 것이라 하겠다.

• 박물관보존과학
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• 제23권
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• pp.49-60
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• 2020

국립중앙박물관 소장 운보문단 보자기(증9393) 유물의 전시와 안전한 보호를 위한 보존처리를 실시하였다. 이후 보존 처리한 직물 무늬의 시대를 추정하기 위하여 함께 기증 된 이항복(1556-1618)의 17세기 활동시기와 후모본(後模本) 초상화의 제작시기인 18세기의 유물과 비교하여 운보문단 보자기 무늬의 구성과 연대를 추정하였다. 운보문단의 시대 추정을 위해 시대가 확실한 유물과 비교한 내용을 확인한 결과는 다음과 같다. 첫째, 이항복의 생몰년(1556-1618)을 기준으로 유사한 시기의 출토복식과 의궤의 표지의 무늬와 비교하였으나 운두와 꼬리크기의 비율에서 확연히 차이가 보여 이항복의 생몰년 대에 제작한 직물로는 추정되지 않다고 판단되었다. 둘째, 이항복의 호성공신과 위성공신 초상 후모본의 제작시기인 18세기 운보문단 직물 무늬와 비교한 결과 가장 유사한 1702년 『숙종인원왕후가례도감의궤』 표지의 운보문단이 확인 되었으며, 이외 1730년대까지의 의궤표지와 출토직물에서 배열, 크기, 비율 등 유사한 구성양식을 나타내고 있었다. 보자기의 정확한 용도는 확인 할 수 없었지만 함께 기증 된 후모본 초상화와 유사한 18세기 초에 제작된 것으로 추정할 수 있다.