On the Strengthening Effects Affecting Tensile and Low Cycle Fatigue Properties of Low-Alloyed Seismic/Fire-Resistant Structural Steels

Jung‑Ho Sim,Tae‑Yeong Kim,Jun‑Yeon Kim,Chi‑Won Kim,Jun‑Ho Chung,Joonoh Moon,Chang‑Hoon Lee,Hyun‑Uk Hong 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.2

In the present study, low carbon ferritic and bainitic steels with different contents of Mo, Ti, and Nb were designed for bothseismic and fire-resistant applications. The microstructure of steels containing 0.3 wt% Mo–0.02 wt% Nb (‘A’ hereinafter)was mainly composed of bainite. By contrast, the microstructure of steels with 0.2 wt% Mo–0.13 wt% Ti (‘B’ hereinafter)consisted of ferrite with a high density of nano-sized (Ti,Mo)-rich MX precipitates. The results showed that the bainiticmicrostructure (‘A’ steel) was quite favorable to high-temperature strength and thermal stability. The yield strength of ‘A’ steelat both room and 600 °C temperatures increased consistently with increasing thermal exposure time (600 °C/200–1000 h),since the precipitation of NbC particles occurred while maintaining bainitic ferrite platelets with a high density of dislocationsduring exposure. In the ‘B’ steel, the formation of nano-sized (Ti,Mo)-rich MX particles was effective to impededislocation movement, leading to excellent plasticity (lower yield ratio) at room temperature. However, their contributionto precipitation hardening was not so much at 600 °C, as compared to the bainitic strengthening. During low cycle fatiguetests at room temperature, the main different feature between the two steels is that the ‘A’ steel showed cyclic softeningwhile cyclic hardening was evident in the ‘B’ steel. The bainitic microstructure showed a better fatigue life due to increasedductility manifested by cyclic softening, by which dislocation cell was developed.

정신분열병과 Glutathione S-Transferase M1유전자 다형성

배치운,조자현,김연주,김태석,김정진,이창욱,이수정,전태연,이철,백인호 大韓神經精神醫學會 2004 신경정신의학 Vol.43 No.5

Objectives : This study aimed to test the possible association between Glutathione S-Transferase Ml gene (GSTMl) variants and schizophrenia. Methods : One hundred and eleven inpatients with schizophrenia and 130 healthy controls were recruited. Genotyping was performed by polymerase chain reaction-based method. Results : The GSTMl null genotype was significantly more frequent in patients with schizophrenia than in controls (p=0.014, odd ratio=1.93, 95% confidence interva1=1.115-3.351), while GSTMl genotype vahants were not associated with either tardive dyskinesia (TD) or total Abnormal Involuntary Movement Scale (AIMS) scores. Conclusion : The present study suggests that the GSTMl polymorphism may confer susceptibility to the development of schizophrenia but not to TD, at least in Korean population.

단백질-다당질 복합겔의 용해도 및 전기영동 특성에 미치는 몇가지 첨가제의 영향

정경임,이동선,하정옥 경남대학교 신소재연구소 1996 論文集 Vol.6 No.-

본 연구에서는 닭고기에서 조제한 근원섬유 단백질(MP)과 MP와 유청 단백질 분리물(WPI)의 혼합물, MP와 대두 단백질 분리물(SPI)의 혼합물 등의 3가지 종류의 단백질과 다당질로서 methyl cellulose, sodium alginate, xanthan gum을 택하여 단백질-다당질의 복합겔을 만들고 NaCl, NaSCN, propylene glycol, 2-mercaptoethanol들의 처리에 의해 단백질-다당질간의 상호작용에 기인하는 겔의 용해도 및 전기영동에 의한 겔 용해에 따른 상징액의 변화 등을 조사함으로써 단백질 식품의 기능적 특성에 미치는 영향을 고찰해 보았다. 겔 용해도는 대체로 모든 다당질에 대해 낮은 용해도를 나타냈으나 세 가지 단백질 시료에 대해 2-mercaptoethanol 처리시 가장 많은 단백질이 용해되어 나온 것으로 나타났다. 2-mercaptoethanol은 단백질간 상호작용, 즉 겔 망상구조를 이루는 sdisulfide 결합을 크게 방해함으로써 가장 높은 용해도를 나타낸 것으로 생각된다. 모든 시료에 대해 NaCl과 NaSCN 용액에 대해서는 아주 낮은 용해도를 보였는데, 이것은 NaCl과 NaSCN은 저 농도일 경우, 단백질 구조를 안정화함으로써 단백질간의 상호작용이 크게 증가되어 용해되는 단백질의 양이 극히 낮아진 것으로 보인다. Xanthan gum은 가장 겔 용해도가 낮았고, 특히 MP와 xanthan gum으로 이루어진 겔에서는 아주 극소량의 단백질이 용해되었다. Methyl cellulose 겔의 경우, 모든 용액에서 단백질이 거의 용해되어 나오지 않았다. 그러나, 1% WPI를 혼합한 경우 역시 겔 용해도가 낮았으며 여전히 MP의 단백질 성분은 용해되어 나오지 않았고 WPI의 주요성분인 α-lactalbumin과 β-latcoblobulin이 많이 용해되어 나왔다. 1% SPI을 혼합한 겔은 셀 용해도도 여전히 낮았으며 전기영동 결과에서도 SPI 성분의 단백질 band가 아주 미약하게 나타났다. 이것으로 보아 WPI는 다소 불안정한 겔을 형성하여 용해도를 증가 시키고 반대로 SPI는 겔을 안정화하여 단백질 용해도를 감소시켰으리라 짐작된다. Sodium alginate 겔의 경우, 단백질 용해도는 아주 낮았으나 3 가지 단백질 시료 모두 용해되어 나왔다. 이것으로 sodium alginate는 단백질과 다소 불안정한 겔을 형성한다는 것을 알 수 있다. X무소무 gum 겔에서도 역시 MP와 MP+SPI 혼합겔은 아주 낮은 겔 용해도를 뒷받침하듯 단백질 band를 거의 확인할 수 없었으나 WPI를 혼합한 겔만이 WPI의 주요성분인 α-lactalbumin과 β-latcoblobulin 성분이 용해되어 나왔다. 즉, methyl cellulose와 xsanthan gum 겔의 경우, 근원섬유 단백질은 거의 용해되어 나오지 않았고 유청 단백질 분리물의 성분이 많이 용해되어 나왔으며 대두 단백질 분리물은 단백질과의 결합력이 커 용해된 단백질 성분이 아주 미약했다. Sodium alginate 겔의 경우 모든 단백질 성분이 용해되어 나온 것으로 보아 sodium alginate는 단백질과 결합하여 불안정한 겔을 형성하는 것으로 나타났다. Interactions between polysaccharides and proteins occur widely in biological system. Their interaction in food system often plays a role in determining the functional properties of these systems. The effects of various reagents such as NaCl. NaSCN. propylene glycol and 2-mercaptoethanol on the gel solubility of heat-induced gels of protein and polysaccharide were studied. Protein samples were myofibrillar proteins(MP) extracted from chicken breast muscle and the combinations of MP plus whey protein isolate(WP1) and MP plus soybean protein isolate(SP1). As polysaccharides in preparation of gels, methyl cellulose, sodium alginate and xanthan gum were used. Protein- polysaccharide composite gels were formed by heating at 80 C for 30 min. In the effects of reagents on gel solubility, 2-mercaptoethanol had higher solubility than other reagents. indicating that 2-mercaptoethanol cleaved disulfide bonds in the protein-polysaccharide composite gels. In order to indicate the composition of protein solubilized from gels by the treatment of various reagents such as 0.1 M NaC1. 0.1 M NaSCN. 20% propylene glycol, 0.04 M 2-mercaptoethanol, the solubilized proteins were analyzed by SDS-PAGE. In methyl cellulose and xanthan gum gels. less protein was solubilized by reagents, but MP gels with WPI was solubilized more abundantly than SPI.

비스판 변이주인 Bacillus polyfermenticus KD21의 주요 생균제 특성

정민용,정황영,하정욱,백현동 慶南大學校 附設 基礎科學硏究所 2002 硏究論文集 Vol.16 No.-

Bacillus polyfermenticus SCD which is commonly called as Bispan strain are being used for functional foods using the treatment of long-term intestinal disorders, since the live strains in the form of active endospores can successfully reach the target intestine in both humans and animals. B. polyfermenticus KD21 was obtained for higher sporulation through the NTG mutagenesis. The cells of B. polyfermenticus KD21 was treated for 24 h in artificial bile after incubation for 2 h in artificial gastric juice and final number of the strain was reached to around 10^8 CFU/㎖. In test of API ZYM kit, β-glucuronidase or β-glucosidase were not produced by B. polyfermenticus KD21. B. polyfermenticus KD21 was resistant to antibiotics such as nisin, tetracyclin, streptomycin, and rifamycin. B. polyfermenticus KD21 was shown to inhibit the growth of Listeria monocytogenes ATCC 19111 completely within 24 h of incubation, which indicates its bactericidal nature.

酸棗仁이 CT105에 의한 신경세포 상해 및 白鼠의 기억에 미치는 영향

정정욱,박창국,박치상,이소연,윤현덕,신오철 대한본초학회 2005 大韓本草學會誌 Vol.20 No.1

Objective: This study was designed to research whether demonstrate neuroprotective and memory enhancing effects of Z1BU, suggesting its beneficial actions for the treatment of AD. Methods: The present study investigated effects of the dichloromethane extract of Semen Zizyphi Spinosae(ZIBU) on neurotoxicity and reactive oxygen species(ROS) and nitric oxide(NO) formation in PC 12 cell line overexpressed with carboxyl-terminal 105 amino acid peptide fragment of amyloid precursor protein(CT105). In addition, the present study evaluated its radical scavenging activity and effects on acetylcholinesterase(AChE) activity. Furthermore, effects on neuronal loss in CAl area and cognitive deficits induced by scopolamine treatment were also evaluated in rats. Result: we found in this study that ZIBU significantly inhibited apoptotic neuronal death induced by CT105 overexpression in PC12 cells, with the IC_(50) value of 23 ㎍/ml. Based on phase-contrast and fluorescence microscopic examinations, ZIBU reversed morphological changes of CT105-expressed PC-12 cells. It was also found that Z1BU significantly induced neurite outgrowth and inhibited formation of ROS and NO.Z1BU scavenged DPPH radicals and inhibited AChE activity. Furthermore, it attenuated memory impairment induced by the injection of scopolamine in rats, based on passive avoidance test. Crystal violet staining of rat brain slices exhibited increase in the viability of pyramidal neurons in hippocampal CAI area. Conclusion: these results demonstrate neuroprotective and memory enhancing effects of ZIBU, suggesting its beneficial actions for the treatment of AD.

수입각증후군에 의한 급성 복증 1례

정은욱,지삼룡,이영태,박지훈,김동기,제인수,채두근,박성재,박은택,이연재,이상혁,설상영,정정명 白中央醫療院 2005 仁濟醫學 Vol.26 No.1

Afferent loop syndrome is an uncommon complication of a gastrectomy and Billroth Ⅱ reconstruction. It may cause symtoms at any time from the first postoperative day to many years after the gastrectomy. Afferent loop syndrome is characterized by abdominal pain, vomiting and elevation of serum amylase. Thus, it is difficult to differentiate afferent loop syndrome from other cause of acute pancreatitis. However, the history of gastrectomy can be an important clue for diagnosing afferent loop syndrome. We experienced one case of chronic afferent loop syndrome with acute pancreatitis. After appropriate management, the abdominal pain disappeared and serum amylase level decreased. We report this case with a review of relevant literatures.

항산화제 첨가 세척에 의한 계육 surimi의 단백질 용해성과 gel 특성의 변화

하정욱 慶南大學校 附設 工業技術硏究所 1997 硏究論文集 Vol.15 No.1

본 연구에서는 계육 surimi제조에 따른 기능성 향상방안을 찾기 위하여 계육의 흉부육과 대퇴육을 각각 시료로 취하여 항산화제 처리시 단백질의 용해성, 겔 강도와 겔 경도 및 겔의 보수성 등에 걸쳐 인산완충액만의 대조구와 비교하여 그 변화를 관찰해 보았다. 우선 단백질 용해성의 경우 흉부육이 대퇴육에 비해 다소 높은 경향을 나타내었고, 이러한 경향은 겔의 강도와 경도 등의 특성이나 겔의 보수성에서도 동일하게 나타났다. 또한 항산화제 처리시는 대조구에 비해 단백질의 용해성, 겔 특성 및 보수성 등의 기능성에서 훨씬 증가되는 경향을 띤 것은 지질 및 단백질의 산패가 방지됨으로써 염용성 단백질이 보호된 데 기인한 것으로 사료된다. Chicken surimi was prepared from chicken breast and leg muscles by repeated washing in the presence of propyl gallate, ascorbate and tripolyphoapate and absence of these antioxidants, respectively. Chicken surimi from breast muscles had higher values in protein solubility, gel strength, gel hardness and water holding capacity of gel than the surimi from leg muscles. Inhibition of oxidation of lipid and protein using antioxidants in the washing solutions increased the functional properties such as protein solubility, gel strength, gel hardness and water holding capacity of gels.

재조합 미생물, Escherichia coli MT201를 이용한 L-Threonine 생산성 향상

하정욱,이만효,김기운,황용일 慶南大學校 附設 基礎科學硏究所 2002 硏究論文集 Vol.16 No.-

의료 및 가축사료용으로 폭 넓은 용도를 지니는 _L-threonine의 대량생산을 위하여 _L-aspartate 생합성계 대사 변이주이며 _L-threonine 생산균주로 개량된 E. coli MT201를 이용하였다. _L-Threonine의 생산성 향상을 위한 일환으로 C. glutamicum으로부터 정제·회수된 pyruvate carboxylase 구조유전자 ORF를 E. coli 발현용 plasmid pTrc99A에 도입하여 plasmid pPC를 제작하였다. 변이주 E. coli MT201 균주에 plasmid pPC를 형질전환법으로 도입하여 과량의 _L-threonine을 생산하는 우수한 재조합 균주인 E. coli MT-pPC을 얻었다. Glucose를 단일 탄소원으로 사용하였을 경우 균체의 생육 및 _L-threonine의 생산량이 감소하는 경향을 보였다. 이를 극복하기 위하여 glucose와 citrate(sodium citrate와 ammonium citrate)를 각각 첨가한 결과 sodium citrate에서 우수한 결과를 flask배양을 통하여 관찰하였다. 적절한 sodium citrate의 첨가 비는 탄소원인 glucose와 sodium citrate의 첨가비가 3.5:1.5일 때 _L-threonine 생산량과 생육이 월등히 향상되었다. 이를 바탕으로 발효조를 이용한 유가배양에서 생산량 75.7g/L를 얻었다. 따라서 본 실험을 통하여 _L-threonine의 생산량이 획기적으로 증가하는 재조합 균주를 개발하였고 생산량도 향상시켰다. _L-Threonine, which is used in the medical field for amino acid infusion and in feedstuff for livestock, is an essential amino acid for man and animals. Microorganisms are genetically bred for industrial production of amino acids including _L-threonine. In this study, Escherichia coli MT201, which was obtained with the view of overproducing for _L-threonine, is the metabolic mutant for a biosynthetic pathway of aspartate family. E. coli MT-pPC was obtained for the improvement of _L-threonine production by introducing plasmid pPC, which is an expression vector for pyruvate carboxylase coding gene(pyc) of Corynebacterium glutamicum ATCC13831 at E. coli MT201 strain. When only glucose was used for carbon source in E. coli MT-pPC, cell growth and _L-threonine production was reduced. For solving this problem, we added glucose and citrates in culture media. From the results, sodium citrate was more effective than ammonium citrate and the optimal ratio, which was the most efficient among those ratio employed here, was the 3.5 : 1.5 of glucose to sodium citrate. In our experiment, _L-threonine production, which was 75.7 g/L for 86 hr by E. coli MT-pPC added with 3.5 : 1.5 ratio of the glucose to sodium citrate in fed-batch culture, and these were higher than 1.2 fold of E. coli MT201 and 3.2 fold of E. coli MT-pPC, respectively, in glucose.

데이타 네트워크에 있어서 경로 선택 알고리즘에 관한 연구

조정복,이재욱,임효택,고석범 東西大學校 1998 동서논문집 Vol.4 No.-

최근에 많은 기업체에서 LAN(Local Area Network)을 기반으로 하는 인터넷 환경을 구축하는 예가 종종 보고되어 지는 것을 보면 네트워크 설계분야에 많은 관심이 집중되고 있음을 알 수 있다. 본 논문에서, Star-Ring LAN상에서 HUB의 할당과 경로 선택 문제를 취급한다. Star-Ring LAN의 설계는 1)HUB들과 사용자 노드(컴퓨터)들 간의 연결, 2)HUB들 간의 경로 선택 문제로 나눌 수 있다. 여기서 제안한 수학적 모델은 HUB의 설치 비용과 각 노드에서 트래픽의 전송 지연 시간을 고려한다. 그리고 최적 해를 탐색하기 위하여 경험적 탐색방법의 하나인 유전 알고리즘(GA:Genetic Algorithm)을 설계한다. 끝으로 본 논문에서 제안된 유전 알고리즘의 성능을 검증하기 위하여 하나의 수치 예를 보인다. Recently, many people are interested in the field of network design again as we know that Intranet environment based on LAN(Local Area Network) is often implemented at many companies. In this paper, we deal with the HUB allocation and routing problem on Star-Ring LAN. The design of Star-Ring LAN is divided into two level problems: 1)connecting between HUBs and user nodes(i.e. computers), and 2) routing between HUBs. In the mathematical model which we will develope, the cost to set up HUBs, and delay time due to communication traffic at each node should be considered as the important factors. Also, we investigate GA(genetic Algorithm)as heuristic method to search the optimal solution. Lastly, we show a numerical example to demonstrate good performances of the proposed method.

산후에 발병한 특발성 부갑상선 기능저하증 I 예

김정인,김상용,신병철,김경남,서영욱,이범주,김진화,배학연 朝鮮大學校 附設 醫學硏究所 2002 The Medical Journal of Chosun University Vol.27 No.2

Hypoparathyroidism is usually the result of an inadvertent surgical removal of all the parathyroid glands, In some instances, not all the tissues are removed, but the remainder undergoes vascular supply compromise secondary to the fibrotic changes in the neck after surgery, Previously, the surgery for hyperthyroidism was the most frequent cause of acquired hypoparathyroidism. Idiopathic hypoparathyroidism is a relatively rare disease that is characterized by hypocalcemia and hyperphosphatemia due to a parathyroid hormone deficiency of an unknown cause, It usually develops at a young age, and shows various clinical symptoms and signs accompanied with hypocalcemia. In addition, it is rarely associated with polyglandular autoimmune syndrome during the follow-up. Hypocalcemia and idiopathic hypoparathyroidism associated with labor and lactation are rarely reported condition previously. We here describe a case of a woman in whom the symptomatic severe hypocalcemia appeared after her delivery. We reviewed all the previously reported cases and suggest a possible physiological explanation for the association between pregnancy, lactation, and the appearance of symptomatic hypocalcemia.