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Ligand Based CoMFA, CoMSIA and HQSAR Analysis of CCR5 Antagonists

  • Gadhe, Changdev G.;Lee, Sung-Haeng;Madhavan, Thirumurthy;Kothandan, Gugan;Choi, Du-Bok;Cho, Seung-Joo
    • Bulletin of the Korean Chemical Society
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    • v.31 no.10
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    • pp.2761-2770
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    • 2010
  • In this study, we have developed QSAR models for a series of 38 piperidine-4-carboxamide CCR5 antagonists using CoMFA, CoMSIA and HQSAR methods. Developed models showed good statistics in terms of $q^2$ and $r^2$ values. Best predictions obtained with standard CoMFA model ($r^2$ = 0.888, $q^2$ = 0.651) and combined CoMSIA model ($r^2$ = 0.892, $q^2$ = 0.665) with electrostatics and H-bond acceptor parameter. The validity of developed models was assessed by test set of 9 compounds, which showed good predictive correlation coefficient for CoMFA (0.804) and CoMSIA (0.844). Bootstrapped analysis showed statistically significant and robust CoMFA (0.968) and CoMSIA (0.936) models. Best HQSAR model was obtained with a $q^2$ of 0.662 and $r^2$ of 0.936 using atom, connection, hydrogen, donor and acceptor as parameters and fragment size (7-10) with optimum number of 6 components. Predictive power of developed HQSAR model was proved by test set and it was found to be 0.728.

A Study of Intercalations-complex of Montmorillonite as Model-System (II) (Model-System으로서의 몬트모릴로나이트의 층간화합물에 관한 연구(II))

  • 조성준;고영신;김인기;오원춘
    • Journal of the Korean Ceramic Society
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    • v.30 no.4
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    • pp.259-264
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    • 1993
  • In this research, the organic tenside R11OSO3- with long alkyl-chain was synthesized, and the intercalationscomplexes fo montmorillonite were formed by the substitution of metallic cation in the montmorilonite by the synthesized organic tenside in following two methods, and the behaviors of the tenside R11OSO3- in the interlamellar space of montmorillonite were studied udner various conditions: 1) In order to protonize the sulfate group of R11OSO3-, the H3O-Montomorillonite, which acts as acid, was synthesized. And then, the organic tenside was intercalated in the interlamellar space of this H3O-Montomorillonite. And thus, the intercalations-complex of R11S-H3O-Montomorillonite was formed. The basal spacing obtained was about 33.84$\AA$. 2) The betaine compound R11OSO3- as a neutral molecule was direct intercalated in the interlamellar space of Na-Montmorillonite under water, and the intercalations-complexes of R11S-H2O-Montmorillonite was synthesized. In this case, the based spacing of bout 23.62$\AA$ was obtained.

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Creep Characterization of Type 316LN and HT-9 Stainless Steels by the K-R Creep Damage Model

  • Kim, U-Gon;Kim, Seong-Ho;Ryu, U-Seok
    • Journal of Mechanical Science and Technology
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    • v.15 no.11
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    • pp.1463-1471
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    • 2001
  • The Kachanov and Rabotnov (K-R) creep damage model was interpreted and applied to type 316LN and HT-9 stainless steels. Seven creep constants of the model, A, B, $textsc{k}$, m, λ, ${\gamma}$, and q were determine d for type 316LN stainless steel. In order to quantify a damage parameter, the cavity was interruptedly traced during creep for measuring cavity area to be reflected into the damage equation. For type 316LN stainless steel, λ= $\varepsilon$R/$\varepsilon$* and λf=$\varepsilon$/$\varepsilon$R were 3.1 and increased with creep strain. The creep curve with λ=3.1 depleted well the experimental data to the full lifetime and its damage curve showed a good agreement when r=24. However for the HT-9 stainless steel, the values of λ and λf were different as λ=6.2 and λf=8.5, and their K-R creep curves did not agree with the experimental data. This mismatch in the HT-9 steel was due to the ductile fracture by softening of materials rather than the brittle fracture by cavity growth. The differences of the values in the above steels were attributed to creep ductilities at the secondary and the tertiary creep stages.

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A Study on the Development of Low Reynolds Number Second Moment Turbulence Model (저레이놀즈수 2차 모멘트 난류모형 개발에 관한 연구)

  • 김명호;최영돈;신종근
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.17 no.6
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    • pp.1596-1608
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    • 1993
  • Low Reynolds number second moment turbulence model which be applicable to the fine gird near the wall region was developed. In this model, turbulence model coefficients in the pressure strain model of the Reynolds stress equation was expressed as functions of turbulence Reynolds number $R_{t}\equivk^{2}/(\nu\varepsilon)).$ In the derivation procedure of the present low Reynolds number algebraic stress model, Laufer's near wall experimental data on Reynolds stresses were curve fitted as functions of R$_{t}$ and the resulting simultaneous equations of the model coefficients were solved by using the boundary conditions at wall and high Reynolds number limiting conditions. Predicted Reynolds stresses and dissipation rate of turbulent kinetic energy etc. in the 2 dimensional parallel, plane channel flow and pipe flow were compared with the preditions obtained by employing the Launder-Shima model, standard algebraic stress model and several experimental data. Results show that all the Reynolds stresses and dissipation rate of turbulent kinetic energy predicted by the present low Reynolds number algebraic stress model agree better with the experimental data than those predicted by other algebraic stress models.

Circ_UBE2D2 Attenuates the Progression of Septic Acute Kidney Injury in Rats by Targeting miR-370-3p/NR4A3 Axis

  • Huang, Yanghui;Zheng, Guangyu
    • Journal of Microbiology and Biotechnology
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    • v.32 no.6
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    • pp.740-748
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    • 2022
  • As circ_UBE2D2 has been confirmed to have targeted binding sites with multiple miRNAs involved in septic acute kidney injury (SAKI), efforts in this study are directed to unveiling the specific role and relevant mechanism of circ_UBE2D2 in SAKI. HK-2 cells were treated with lipopolysaccharide (LPS) to construct SAKI model in vitro. After sh-circ_UBE2D2 was transfected into cells, the transfection efficiency was detected by qRT-PCR, cell viability and apoptosis were determined by MTT assay and flow cytometry, and expressions of Bcl-2, Bax and Cleaved-caspase 3 were quantified by western blot. Target genes associated with circ_UBE2D2 were predicted using bioinformatics analysis. After the establishment of SAKI rat model, HE staining and TUNEL staining were exploited to observe the effect of circ_UBE2D2 on tissue damage and cell apoptosis. The expression of circ_UBE2D2 was overtly elevated in LPS-induced HK-2 cells. Sh-circ_UBE2D2 can offset the inhibition of cell viability and the promotion of cell apoptosis induced by LPS. Circ_UBE2D2 and miR-370-3p as well as miR-370-3p and NR4A3 have targeted binding sites. MiR-370-3p inhibitor reversed the promoting effect of circ_UB2D2 silencing on viability of LPS-treated cells, but shNR4A3 neutralized the above inhibitory effect of miR-370-3p inhibitor. MiR-370-3p inhibitor weakened the down-regulation of NR4A3, Bax and Cleaved caspase-3 and the up-regulation of Bcl-2 induced by circ_UB2D2 silencing, but these trends were reversed by shNR4A3. In addition, sh-circ_UBE2D2 could alleviate the damage of rat kidney tissue. Circ_UBE2D2 mitigates the progression of SAKI in rats by targeting miR-370-3p/NR4A3 axis.

Analysis Method of the Effect of National R&D investments on Economic Growth

  • Choi, Eun-Chul
    • Journal of Technology Innovation
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    • v.7 no.2
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    • pp.1-20
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    • 1999
  • This paper investigates the effects of various R&D investments on economic growth empirically. To this end, the relationships between various R&D investments and economic growth are analysed, and the rates of return of R&D investments are estimated. Furthermore, the effect of government R&D investment on private sector R&D investment, and the effect of social factors, which affect the relationship between the R&D inputs and economic growth, are analysed. Based on the results of this analysis, a simulation model is developed, which shows the relationship between R&D investments and economic growth rate; this model is verified by analysing the correlation between the actual and the estimated economic growth rate, using the data between 1981 and 1995 of eight selected countries. The validation results show that the simulation model has sufficient accuracy to be used for evaluating and proposing R&D policies for the countries for which appropriate data is available. However, the time-lag effect, which is naturally believed to exist between the R&D input and the economic growth, could not be analysed in a mathematical form, because of the lack of the data to establish this relationship. Thus, when estimating the relationship between them, the time-lag effect in this relationship was included implicitly by using the data of fifteen years.

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Estimate of the Basic Reproduction Number for COVID-19: A Systematic Review and Meta-analysis

  • Alimohamadi, Yousef;Taghdir, Maryam;Sepandi, Mojtaba
    • Journal of Preventive Medicine and Public Health
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    • v.53 no.3
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    • pp.151-157
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    • 2020
  • Objectives: The outbreak of coronavirus disease 2019 (COVID-19) is one of the main public health challenges currently facing the world. Because of its high transmissibility, COVID-19 has already caused extensive morbidity and mortality in many countries throughout the world. An accurate estimation of the basic reproduction number (R0) of COVID-19 would be beneficial for prevention programs. In light of discrepancies in original research on this issue, this systematic review and meta-analysis aimed to estimate the pooled R0 for COVID-19 in the current outbreak. Methods: International databases (including Google Scholar, Science Direct, PubMed, and Scopus) were searched to identify studies conducted regarding the R0 of COVID-19. Articles were searched using the following keywords: "COVID-19" and "basic reproduction number" or "R0." The heterogeneity among studies was assessed using the I2 index, the Cochran Q test, and T2. A random-effects model was used to estimate R0 in this study. Results: The mean reported R0 in the identified articles was 3.38±1.40, with a range of 1.90 to 6.49. According to the results of the random-effects model, the pooled R0 for COVID-19 was estimated as 3.32 (95% confidence interval, 2.81 to 3.82). According to the results of the meta-regression analysis, the type of model used to estimate R0 did not have a significant effect on heterogeneity among studies (p=0.81). Conclusions: Considering the estimated R0 for COVID-19, reducing the number of contacts within the population is a necessary step to control the epidemic. The estimated overall R0 was higher than the World Health Organization estimate.

A Study on R&D Project Planning Selection Evaluation Indicators based on CIPP model (CIPP모형을 활용한 R&D과제기획 선정평가 도구 개발 연구 : K연구원 중심으로)

  • Hyun-Ku Min
    • Journal of Technology Innovation
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    • v.31 no.3
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    • pp.171-199
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    • 2023
  • The purpose of this study was to develop an evaluation tool for selecting new projects for R&D project planning level of K Research Institute. For this purpose, items and questions for R&D project selection evaluation were developed based on the CIPP model and previous studies on selection evaluation and evaluation indicators for research project evaluation, and then two Delphi surveys were conducted. The developed evaluation tool was surveyed by 13 experts to verify contents validity ratio, convergence and consensus. The finally selected evaluation tool for R&D project planning consisted of 21 questions in 8 items, including 5 questions for context evaluation, 2 questions for input evaluation, 8 questions for process evaluation, and 6 questions for product evaluation. The evaluation tool developed will contribute to the solution of problems in the bottom-up planning process and to the improvement of the planning competence of the researchers. It will also contribute to improve the consistency and efficiency of evaluation during the selection process.

Prediction of Distillation Column Temperature Using Machine Learning and Data Preprocessing (머신 러닝과 데이터 전처리를 활용한 증류탑 온도 예측)

  • Lee, Yechan;Choi, Yeongryeol;Cho, Hyungtae;Kim, Junghwan
    • Korean Chemical Engineering Research
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    • v.59 no.2
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    • pp.191-199
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    • 2021
  • A distillation column, which is a main facility of the chemical process, separates the desired product from a mixture by using the difference of boiling points. The distillation process requires the optimization and the prediction of operation because it consumes much energy. The target process of this study is difficult to operate efficiently because the composition of feed flow is not steady according to the supplier. To deal with this problem, we could develop a data-driven model to predict operating conditions. However, data preprocessing is essential to improve the predictive performance of the model because the raw data contains outlier and noise. In this study, after optimizing the predictive model based long-short term memory (LSTM) and Random forest (RF), we used a low-pass filter and one-class support vector machine for data preprocessing and compared predictive performance according to the method and range of the preprocessing. The performance of the predictive model and the effect of the preprocessing is compared by using R2 and RMSE. In the case of LSTM, R2 increased from 0.791 to 0.977 by 23.5%, and RMSE decreased from 0.132 to 0.029 by 78.0%. In the case of RF, R2 increased from 0.767 to 0.938 by 22.3%, and RMSE decreased from 0.140 to 0.050 by 64.3%.

Prediction of Acute Toxicity to Fathead Minnow by Local Model Based QSAR and Global QSAR Approaches

  • In, Young-Yong;Lee, Sung-Kwang;Kim, Pil-Je;No, Kyoung-Tai
    • Bulletin of the Korean Chemical Society
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    • v.33 no.2
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    • pp.613-619
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    • 2012
  • We applied several machine learning methods for developing QSAR models for prediction of acute toxicity to fathead minnow. The multiple linear regression (MLR) and artificial neural network (ANN) method were applied to predict 96 h $LC_{50}$ (median lethal concentration) of 555 chemical compounds. Molecular descriptors based on 2D chemical structure were calculated by PreADMET program. The recursive partitioning (RP) model was used for grouping of mode of actions as reactive or narcosis, followed by MLR method of chemicals within the same mode of action. The MLR, ANN, and two RP-MLR models possessed correlation coefficients ($R^2$) as 0.553, 0.618, 0.632, and 0.605 on test set, respectively. The consensus model of ANN and two RP-MLR models was used as the best model on training set and showed good predictivity ($R^2$=0.663) on the test set.