산화툴륨의 결함구조와 전기전도성에 대한 연구

최재시,정원양,김진호,이창환 연세대학교 자연과학연구소 1985 學術論文集 Vol.14 No.-

산화툴륨의 전기전도도를 400~1100℃의 온도영역과 10^-6~10^-1atm의 산소분압범위에서 측정하였다. 일정한 산소분압에서 전기전도도의 대수값을 절대온도의 역수에 대하여 도시한결과 직선관계를 얻었으며 inflection point가 나타났다. 활성화에너지는 고온영역에서 34.5kcal/mole, 저온영역에서 19.3kcal/mole이었다. 전기전도도의 산소분압의존성은 직선관계를 나타내었으며 600~1100℃의 온도영역에서 σ∝Po_2^1/5.3, 400~600℃의 온도영역에서σ∝Po_2^1/6.3이었다. 고온영역에서의 주결함은 V_??이며, 저온영역에서는 O_?? 임이 밝혀졌다. 전도도의 온도 및 산소분압의존성을 해석하였으며, 전도메카니즘을 제시하였다. The electrical conductivity of thulium sesquioxide has been measured from 400 to 1100℃ under oxygen partial pressure (Po_2) of 10^-6 to 10^-1 atm. Plots of log conductivity vs. 1/T at constant Po_2 are found to be linear with inflection point and the activation energies obtained from the slopes are 34.5kcal/mole in the higher temperature region and 19.3kcal/mole in the lower temperature region. The Po_2 dependences of the electrical conductivity are found to be linear and closely approximated by σ∝Po_2^1/5.3 in the temperature range of 600-1100℃ and σ∝Po_2^1/6.3 in the range of 400-600℃. The dominant defect is V_?? in the higher temperature region and O_?? in the lower temperature region. The interpretations of conductivity dependences on temperature and Po_2 are presented and conduction mechanisms are suggested to illustrate the data.

Clinical Characteristics and Risk Factors for Mortality in Critical COVID-19 Patients Aged 50 Years or Younger During Omicron Wave in Korea: Comparison With Patients Older Than 50 Years of Age

Shi Hye Jin,Yang Jinyoung,Eom Joong Sik,Ko Jae-Hoon,Peck Kyong Ran,Kim Uh Jin,Jung Sook In,Kim Seulki,Seok Hyeri,Hyun Miri,Kim Hyun Ah,Kim Bomi,Joo Eun-Jeong,Cheong Hae Suk,Jun Cheon Hoo,Wi Yu Mi,Kim 대한의학회 2023 Journal of Korean medical science Vol.38 No.28

Background: The coronavirus disease 2019 (COVID-19) pandemic has caused the death of thousands of patients worldwide. Although age is known to be a risk factor for morbidity and mortality in COVID-19 patients, critical illness or death is occurring even in the younger age group as the epidemic spreads. In early 2022, omicron became the dominant variant of the COVID-19 virus in South Korea, and the epidemic proceeded on a large scale. Accordingly, this study aimed to determine whether young adults (aged ≤ 50 years) with critical COVID-19 infection during the omicron period had different characteristics from older patients and to determine the risk factors for mortality in this specific age group. Methods: We evaluated 213 critical adult patients (high flow nasal cannula or higher respiratory support) hospitalized for polymerase chain reaction-confirmed COVID-19 in nine hospitals in South Korea between February 1, 2022 and April 30, 2022. Demographic characteristics, including body mass index (BMI) and vaccination status; underlying diseases; clinical features and laboratory findings; clinical course; treatment received; and outcomes were collected from electronic medical records (EMRs) and analyzed according to age and mortality. Results: Overall, 71 critically ill patients aged ≤ 50 years were enrolled, and 142 critically ill patients aged over 50 years were selected through 1:2 matching based on the date of diagnosis. The most frequent underlying diseases among those aged ≤ 50 years were diabetes and hypertension, and all 14 patients who died had either a BMI ≥ 25 kg/m2 or an underlying disease. The total case fatality rate among severe patients (S-CFR) was 31.0%, and the S-CFR differed according to age and was higher than that during the delta period. The S-CFR was 19.7% for those aged ≤ 50 years, 36.6% for those aged > 50 years, and 38.1% for those aged ≥ 65 years. In multivariate analysis, age (odds ratio [OR], 1.084; 95% confidence interval [CI], 1.043–1.127), initial low-density lipoprotein > 600 IU/L (OR, 4.782; 95% CI, 1.584–14.434), initial C-reactive protein > 8 mg/dL (OR, 2.940; 95% CI, 1.042–8.293), highest aspartate aminotransferase > 200 IU/L (OR, 12.931; 95% CI, 1.691–98.908), and mechanical ventilation implementation (OR, 3.671; 95% CI, 1.294–10.420) were significant independent predictors of mortality in critical COVID-19 patients during the omicron wave. A similar pattern was shown when analyzing the data by age group, but most had no statistical significance owing to the small number of deaths in the young critical group. Although the vaccination completion rate of all the patients (31.0%) was higher than that in the delta wave period (13.6%), it was still lower than that of the general population. Further, only 15 (21.1%) critically ill patients aged ≤ 50 years were fully vaccinated. Overall, the severity of hospitalized critical patients was significantly higher than that in the delta period, indicating that it was difficult to find common risk factors in the two periods only with a simple comparison. Conclusion: Overall, the S-CFR of critically ill COVID-19 patients in the omicron period was higher than that in the delta period, especially in those aged ≤ 50 years. All of the patients who died had an underlying disease or obesity. In the same population, the vaccination rate was very low compared to that in the delta wave, indicating that non-vaccination significantly affected the progression to critical illness. Notably, there was a lack of prescription for Paxlovid for these patients although they satisfied the prescription criteria. Early diagnosis and active initial treatment was necessary, along with the proven methods of vaccination and personal hygiene. Further studies are needed to determine how each variant affects critically ill patients.

Hematopoietic Reconstitution of CD34+ Cells Derived from Short-term Cultured Cord Blood Mononuclear Cells

Shi Yang,Haibo Cai,Huili Jin,Jinli Fan,Wen-song Tan 한국생물공학회 2009 Biotechnology and Bioprocess Engineering Vol.14 No.4

Ex vivo expansion of hematopoietic stem cells (HSCs) is very important for clinical applications of cord blood (CB). With the aim to find proper culture duration for ex vivo expansion, mononuclear cells (MNC) was applied as starting culture cells to expand HSCs and the repopulating potential of seven-day and fourteen-day cultured CD34+ cells were compared. The average expansion of total cells and CD34+ cells cultured for 7 days were higher than those cultured for 14 days. The results of phenotypic analysis of fresh and cultured cells showed that the percentage of CD3+ cells declined and the percentage of CD33+ cells increased during culture. The engraftment levels of fourteen-day cultured CD34+ cells were higher than those of fresh and seven-day cultured CD34+ cells. Fourteen-day cultured CD34+ cells also showed better multilineage reconstitution ability than fresh and seven-day cultured CD34+ cells. The results of the present study demonstrated that prolonged culture could preserve the hematopoietic reconstitution ability of ex vivo cultured CB cells and improve the engraftment level in NOD/SCID mice.

Original Article : The Simple Predictors of Pseudomembranous Colitis in Patients with Hospital-Acquired Diarrhea: A Prospective Observational Study

( Bo Kyung Yang ),( Byung Ju Do ),( Eun Jung Kim ),( Ji Un Lee ),( Mi Hee Kim ),( Jin Gu Kang ),( Hyoung Su Kim ),( Kyung Ho Kim ),( Myoung Kuk Jang ),( Jin Heon Lee ),( Hak Yang Kim ),( Woon Geon Shi The Editorial Office of Gut and Liver 2014 Gut and Liver Vol.8 No.1

Background/Aims: As the incidence rate of and mortality from pseudomembranous colitis (PMC) are increasing worldwide, it is important to study the simple predictive risk factors for PMC among patients with hospital-acquired diarrhea (HAD). This study focused on identifying the clinical risk factors that can easily predict PMC. Methods: The presumed HAD patients were prospectively recruited at the Hallym University Kangdong Sacred Heart Hospital. Results: Age of 70 and older (adjusted odds ratio [OR], 1.76, 95% confidence interval [CI], 1.12 to 0.75), use of proton pump inhibitors (adjusted OR, 4.07, 95% CI, 2.512 to 6.57), use of cephalosporins (adjusted OR, 2.99, 95% CI, 1.82 to 4.94), and underlying cancer (adjusted OR, 1.72, 95% CI, 1.04 to 2.82) were independent risk factors for PMC in the multivariate logistic regression analysis. The prevalence of PMC was very low in the patients with HAD who exhibited no risk factors. Conclusions: The risk factors for PMC in patients with HAD included cephalosporin use, proton pump inhibitor use, old age, and cancer. Considering the strongly negative predictive values of these risk factors, endoscopic evaluation can be delayed in patients with HAD without risk of developing PMC. (Gut Liver 2014,8:41-48)

Two Compound Heterozygous Were Identified in SLC26A4 Gene in Two Chinese Families With Enlarged Vestibular Aqueduct

Yongbo Yu,Yang Yang,Jie Lu,Yaqiong Jin,Yeran Yang,Enyu Hong,Jin Shi,Feng Chen,Shujing Han,Ping Chu,Yongli Guo,Xin Ni 대한이비인후과학회 2019 Clinical and Experimental Otorhinolaryngology Vol.12 No.1

Objectives. To investigate the genetic causes of hearing loss with enlarged vestibular aqueduct (EVA) in two children from unrelated two Chinese families. Methods. Sanger sequencing of all coding exons in SLC26A4 (encoding Pendrin protein) was performed on the two patients, their sibling and parents respectively. To predict and visualize the potential functional outcome of the novel variant, model building, structure analysis, and in silico analysis were further conducted. Results. The results showed that the proband from family I harbored a compound heterozygote of SLC26A4 c.1174A>T (p.N392Y) mutation and c.1181delTCT (p.F394del) variant in exon 10, potentially altering Pendrin protein structure. In family II, the proband was identified in compound heterozygosity with a known mutation of c.919-2A>G in the splice site of intron 7 and a novel mutation of c.1023insC in exon 9, which results in a frameshift and translational termination, consequently leading to truncated Pendrin protein. Sequence homology analysis indicated that all the mutations localized at high conservation sites, which emphasized the significance of these mutations on Pendrin spatial organization and function. Conclusion. In summary, this study revealed two compound heterozygous mutations (c.1174A>T/c.1181delTCT; c.919-2A>G/c.1023insC) in Pendrin protein, which might account for the deafness of the two probands clinically diagnosed with EVA. Thus this study contributes to improve understanding of the causes of hearing loss associated with EVA and develop a more scientific screening strategy for deafness.

A New Kind of Secure Electronic Communication Technology VT Position Code Communication Technology and Its Implementation

Shi-Ying Zhou,Gui-He Qin,Yang Xun,Yu-Bo Jin 보안공학연구지원센터 2008 International Journal of Security and Its Applicat Vol.2 No.3

Eelectronic device technology has been monopolized by binary system for many years. The circs not only makes it impossible to break through the existing technology bottleneck, but also brings a lot of potential safety problems. Aiming at this question, a new electronic communication technology is presented in this paper. The technology quantifies the time axis and the voltage axis synchronously, uses the quantified time dot as the address of the communication, and realizes the transmission of the multi-system [1] data via transmitting the multi-steps voltage quantification. The technology solves the bottleneck problem of the speed, circuit and electromagnetism in the electronic communication, changes the binary system coding mode and communication connection form of the electronic device, reduces the transmission quantity of the redundant information, advances the security of electronic system and network, debases the complexity of the devices connection, enhances the rate of the processing and the transmission, simplifies the transformation between the difference protocols. The experimental results approve the validity and the robustness of the technology.

Novel space vector-based PWM strategy with minimal circulating current and line-current ripple for two parallel interleaved inverters

Jin, Xiao-Liang,Liu, Sheng-Fu,Shi, Wen,Yang, Huan,Zhao, Rong-Xiang The Korean Institute of Power Electronics 2021 JOURNAL OF POWER ELECTRONICS Vol.21 No.2

Existing PWM methods suffer from a trade off between zero-sequence circulating current (ZSCC) and line-current ripple, which are two major concerns of two parallel interleaved two-level (2L) voltage-source converters (VSCs). Thus, this paper introduces a novel space vector-based PWM strategy to reduce both line-current ripple and ZSCC. Given the redundancy of the vector combination of two parallel interleaved converters, this paper proposes eight optimal vector sequences, which simultaneously optimizes the ZSCC and the line-current ripple. Then, a carrier-based scheme is applied to yield optimal vector sequences, which simplifies the implementation procedure. Furthermore, this paper quantitatively compares both the ZSCC and the line-current ripple of the proposed method to those of existing PWM schemes. This comparison confirms that the proposed method is superior to existing PWM schemes in terms of current ripple and ZSCC. Finally, experimental results further verify the theoretical analysis and the effectiveness of the proposed strategy.

Microwave-Accelerated Click Chemistry: Expeditious Synthesis of Novel Triazole-linked Salicylic β-D-O-Glycosides with PTP1B Inhibitory Activity

Yang, Jin-Wei,Li, Cui,He, Xiao-Peng,Zhao, Hong,Gao, Li-Xin,Zhang, Wei,Shi, Xiao-Xin,Tang, Yun,Li, Jia,Chen, Guo-Rong Korean Chemical Society 2010 Bulletin of the Korean Chemical Society Vol.31 No.11

The incorporation of microwave irradiation with the prevalent "click chemistry" is currently of considerable synthetic interest. We describe here the introduction of such laboratorial shortcut into carbohydrate-based drug discovery, resulting in the rapid formation of a series of triazole-linked salicylic $\beta$-D-O-glycosides with biological activities. All "clicked" products were achieved in excellent yields ($\approx$ 90%) within only a quarter. In addition, based on the structural characteristics of the afforded glycomimetics, their inhibitory activities were evaluated toward protein tyrosine phosphatases 1B (PTP1B) and a panel of homologous protein tyrosine phosphatases (PTPs). Docking simulation was also conducted to plausibly propose binding modes of this glycosyl salicylate series with the enzymatic target.

Liriodenine Inhibits Dopamine Biosynthesis and L-DOPA-Induced Dopamine Content in PC12 Cells

Jin, Chun-Mei,Lee, Jae-Joon,Yang, Yoo-Jung,Kim, Yu-Mi,Kim, Young-Kyoon,Ryu, Shi-Yong,Lee, Myung-Koo 대한약학회 2007 Archives of Pharmacal Research Vol.30 No.8

The inhibitory effects of liriodenine, an aporphine isoquinoline alkaloid, on dopamine biosynthesis and L-DOPA-induced dopamine content increases in PC12 cells were investigated. Treatment of PC12 cells with 5-10 ${\mu}M$ liriodenine significantly decreased the intracellular dopamine content in a concentration-dependent manner ($IC_{50}$ value, 8.4 ${\mu}M$). Liriodenine was not cytotoxic toward PC12 cells at concentrations up to 20 ${\mu}M$. Tyrosine hydroxylase (TH) and aromatic L-amino acid decarboxylase (AADC) activities were inhibited by 10 ${\mu}M$ liriodenine to 20-70% and 10-14% of control levels at 3-12 h, respectively; TH activity was more influenced than AADC activity. The levels of TH mRNA, intracellular cyclic AMP and basal $Ca^{2+}$ concentration were also decreased by 10 ${\mu}M$ liriodenine. In addition, 10 ${\mu}M$ liriodenine reduced L-DOPA (20-100 ${\mu}M$)-induced increases in dopamine content. However, 10 ${\mu}M$ liriodenine resulted in a protective effect against L-DOPA (50-100 ${\mu}M$)-induced cytotoxicity. These results suggest that liriodenine regulates dopamine biosynthesis by partially reducing TH activity and TH gene expression and has protective effects against L-DOPA-induced cytotoxicity in PC12 cells.

Association between Ras association domain family 1A Promoter Methylation and Esophageal Squamous Cell Carcinoma: a Meta-analysis

Yang, Jian-Zhou,Ji, Ai-Fang,Wang, Jin-Sheng,Chen, Zhong-Yi,Wen, Shi Wu Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.9

RASSF1A has been reported to be a candidate tumor suppressor in esophageal squamous cell carcinoma (ESCC). However, the association between RASSF1A promoter methylation and ESCC remains unclear. Eligible studies were identified through searching PubMed, Medline, Web of Science, and the China National Knowledge Infrastucture database. Studies were pooled and odds ratios (ORs) with corresponding confidence intervals (CIs) were calculated. Funnel plots were also performed to evaluate publication bias. Twelve studies involving 859 cases and 675 controls were included in this meta-analysis. A significant association was observed between RASSF1A methylation and ESCC overall (OR = 11.7, 95% CI: 6.59-20.9, z=8.36, P<0.00001). Subgroup analysis showed that the OR for heterogeneous tissues was 5.35 (95% CI = 2.95-9.71) while for autologous tissues it was 16.0 (8.31-30.96). For patient sample size, the OR for the <50 subgroup was 9.92 (95% CI = 2.88-34.2) and for the 50 case group was 13.1 (95% CI = 6.59-25.91). The OR for a relationship between RASSF1A methylation and TNM stages was 0.27 (95% CI=0.10-0.77), whereas there were no significant differences in RASSF1A methylation in relation to gender and differentiation among ESCC cases. This meta-analysis suggests a significant association between RASSF1A methylation and ESCC.