• Title/Summary/Keyword: RIF

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Understanding Rifampicin Resistance in Tuberculosis through a Computational Approach

  • Kumar, Satish;Jena, Lingaraja
    • Genomics & Informatics
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    • v.12 no.4
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    • pp.276-282
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    • 2014
  • The disease tuberculosis, caused by Mycobacterium tuberculosis (MTB), remains a major cause of morbidity and mortality in developing countries. The evolution of drug-resistant tuberculosis causes a foremost threat to global health. Most drug-resistant MTB clinical strains are showing resistance to isoniazid and rifampicin (RIF), the frontline anti-tuberculosis drugs. Mutation in rpoB, the beta subunit of DNA-directed RNA polymerase of MTB, is reported to be a major cause of RIF resistance. Amongst mutations in the well-defined 81-base-pair central region of the rpoB gene, mutation at codon 450 (S450L) and 445 (H445Y) is mainly associated with RIF resistance. In this study, we modeled two resistant mutants of rpoB (S450L and H445Y) using Modeller9v10 and performed a docking analysis with RIF using AutoDock4.2 and compared the docking results of these mutants with the wild-type rpoB. The docking results revealed that RIF more effectively inhibited the wild-type rpoB with low binding energy than rpoB mutants. The rpoB mutants interacted with RIF with positive binding energy, revealing the incapableness of RIF inhibition and thus showing resistance. Subsequently, this was verified by molecular dynamics simulations. This in silico evidence may help us understand RIF resistance in rpoB mutant strains.

An Analysis of the RDF Authorization Conflict Problem by RIF Inference (RIF 추론에 의한 RDF 권한 충돌 문제 분석)

  • Kim, Jae-Hoon;Lee, Jae-Keun;Kang, Il-Yong;Lee, Yong-Woo;Park, Seog
    • Proceedings of the Korean Information Science Society Conference
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    • 2012.06c
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    • pp.1-3
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    • 2012
  • RIF(Rule Interchange Format)는 시맨틱 웹의 구조중 규칙 계층을 담당하며 기존에 사용되고 있는 여러 상이한 규칙 언어들 간의 호환을 위한 표준 규칙 언어라고 할 수 있다. RIF는 W3C에서 승인되었다. 시맨틱웹을 위한 표준 온톨로지 언어로는 RDF와 OWL이 있으며, 최근 RDF 데이터에 대한 접근제어 (Access Control) 메커니즘과 관련하여 일부 학술적 연구가 수행되었다. 본 논문에서는 RDF 데이터와 결합될 수 있는 RIF 추론 규칙에 대해 이미 제안한 RDF 접근제어 메커니즘을 확장하고자 한다. RDF 데이터에 대해 명세된 접근 권한은 RIF 추론에 의하여 권한 충돌이 발생할 수 있고, 그로 인해 접근 권한은 허용되지 않을 수 있다. 본 논문에서는 어떤 조건에서 이러한 RIF 추론에 의한 권한 충돌이 발생하는 지를 분석하며, 이미 제안한 그래프 레이블링을 사용하는 충돌 발견 방법이 RIF 추론과 관련하여서도 효율적임을 보인다. 실험에서는 제안된 방법이, 비록 포함관계 추론에 특화 되었지만, Chase 알고리즘에 기반한 다른 연구에서의 방법보다 발견 시간을 크게 감소시킴을 보인다.

Numerical Simulation of Auto-ignition Process of Diesel Sprays Using Detailed Chemistry and Representative Flamelet Model (상세 화학 반응 모델 및 RIF 모델을 이용한 디젤 분무의 자발화 과정 해석)

  • Yu, Y.W.;Kim, S.K.;Kim, Y.M.;Soh, J.L.
    • Journal of ILASS-Korea
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    • v.5 no.2
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    • pp.61-67
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    • 2000
  • The interaction between chemistry and turbulence is treated by employing the Representative Interactive Flamelet (RIF) Model. The detailed chemistry of 114 elementary steps and 44 chemical species is adopted for the n-heptane/air reaction. In order to account for the spatial inhomogeneity of the scalar dissipation rate, the multi-RIF is used. The effect of the number of RIF on ignition delay is discussed in detail. Numerical results indicate that the present RIF approach successfully predicts the ignition delay time as well as the essential features of a spray auto-ignition process.

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Design and analysis of RIF scheme to improve the CFD efficiency of rod-type PWR core

  • Chen, Guangliang;Qian, Hao;Li, Lei;Yu, Yang;Zhang, Zhijian;Tian, Zhaofei;Li, Xiaochang
    • Nuclear Engineering and Technology
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    • v.53 no.10
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    • pp.3171-3181
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    • 2021
  • This research serves to advance the development of engineering computational fluid dynamics (CFD) computing efficiency for the analysis of pressurized water reactor (PWR) core using rod-type fuel assemblies with mixing vanes (one kind of typical PWR core). In this research, a CFD scheme based on the reconstruction of the initial fine flow field (RIF CFD scheme) is proposed and analyzed. The RIF scheme is based on the quantitative regulation of flow velocities in the rod-type PWR core and the principle that the CFD computing efficiency can be improved greatly by a perfect initialization. In this paper, it is discovered that the RIF scheme can significantly improve the computing efficiency of the CFD computation for the rod-type PWR core. Furthermore, the RIF scheme also can reduce the computing resources needed for effective data storage of the large fluid domain in a rod-type PWR core. Moreover, a flow-ranking RIF CFD scheme is also designed based on the ranking of the flow rate, which enhances the utilization of the flow field with a closed flow rate to reconstruct the fine flow field. The flow-ranking RIF CFD scheme also proved to be very effective in improving the CFD efficiency for the rod-type PWR core.

Recent Research Trends of Acupuncture Treatment for Recurrent Implantation Failure (RIF) Patients in In Vitro Fertilization (체외수정에서 반복 착상 실패(RIF) 환자 침치료 최근 연구 동향)

  • Se-Yeon Cho;Seung-Kyu Kim;Deok-Sang Hwang;Jin-Moo Lee;Jun-Bock Jang;Chang-Hoon Lee
    • The Journal of Korean Obstetrics and Gynecology
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    • v.37 no.2
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    • pp.120-134
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    • 2024
  • Objectives: This research aimed at investigating the trends of acupuncture treatment for Recurrent Implantation Failure (RIF) patients in IVF. Methods: Studies were searched from PubMed, Cochrane Library, EMBASE, CNKI up to April 2024. Terms as 'Implantation failure', 'Recurrent implantation failure', 'Repeated implantation failure', 'RIF' and 'Acupuncture', 'Electroacupuncture', 'Needling' were used. Results: Of 136 screened, 10 studies are selected and analyzed. Studies were conducted using manual acupuncture and electroacupuncture. The results showed that acupuncture (electroacupuncture) treatment for RIF patients is effective in improving clinical pregnancy rate, endometrial blood flow, uterus morphology, endometrium thickness. The most frequently used acupoints were 三陰交 (SP6) and 子宮 (EX-CA1). Conclusions: Included studies showed that acupuncture (electroacupuncture) might have effect on RIF. Further research and meta-analysis should be conducted to verify its therapeutic mechanisms and safety.

TRANSIENT FLAMELET MODELING FOR COMBUSTION PROCESSES OF HSDI DIESEL ENGINES

  • Kim, H.J.;Kang, S.M.;Kim, Y.M.;Lee, J.H.;Lee, J.K.
    • International Journal of Automotive Technology
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    • v.7 no.2
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    • pp.129-137
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    • 2006
  • The representative interactive flamelet(RIF) concept has been applied to numerically simulate the combustion processes and pollutant formation in the HSDI diesel engine. In order to account for the spatial inhomogeneity of the scalar dissipation rate, the eulerian particle flamelet model using the multiple flamelets has been employed. The vaporization effects on turbulence-chemistry interaction are included in the present RIF procedure. the results of numerical modeling using the rif concept are compared with experimental data and with numerical results of the widely-used ad-hoc combustion model. Numerical results indicate that the rif approach including the vaporization effect on turbulent spray combustion process successfully predicts the ignition delay characteristics as well as the pollutant formation in the HSDI diesel engines.

Genetic Analysis of Recombinants by Interspecific Protoplast Fusion of Coryneform Bacteria and Their L-glutamate & L-glutamine Production (Corynebacterium 세균의 이종간 원형질체 융합에 의한 재조합주의 유전학적 분석과 L-glutamate와 L-glutamine 생성)

  • 백선영;이혜경;최순영;김종욱;이세배;임번삼;민경희
    • Microbiology and Biotechnology Letters
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    • v.18 no.3
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    • pp.296-300
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    • 1990
  • For interspecific portoplast fusion, Brevibacterium flauum lOAHR (Rifr axg his) and Corynebacterium glutamicum 11TS ($Sm-r$ trp) were induced by UV and NTG treatment. The protoplast fusion frequency between E. flavum XOAHR and C. glutamicum llTS was $3.7\times 10^{-6}$ with the lysozyme treatment (300 P $\mu g$ml) for 18 hrs. Genotypes of recombinants were analized as FMM ($Rif^r\; Sm^r$), FA (Rift $Sm^r$ arg), FH ($Rif^r\; Sm^r$ his), FT ($Rif^r\; Sm^r$ trp), FAH ($Rif^r\; Sm^r$ arg trp), FAT ($Rif^r\; Sm^r$ arg trp), and FAHT ($Rif^r\; Sm^r$ arg his trp). FAH 1 produced 12 fold of glutamate production compared to parental type, E. flauum 10AHR. In glutamine productivity, it produced 2.6 fold to parental type, C. glutamicum 11TS. Production of glutamate or glutamine by recombinants was involved in the specific activities of glutamate dehydrogenase (GDH) and glutamine synthetase (GS), respectively.

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Comparative Performance of Line Probe Assay (Version 2) and Xpert MTB/RIF Assay for Early Diagnosis of Rifampicin-Resistant Pulmonary Tuberculosis

  • Yadav, Raj Narayan;Singh, Binit Kumar;Sharma, Rohini;Chaubey, Jigyasa;Sinha, Sanjeev;Jorwal, Pankaj
    • Tuberculosis and Respiratory Diseases
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    • v.84 no.3
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    • pp.237-244
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    • 2021
  • Background: The emergence of drug-resistant tuberculosis (TB), is a major menace to cast off TB worldwide. Line probe assay (LPA; GenoType MTBDRplus ver. 2) and Xpert MTB/RIF assays are two rapid molecular TB detection/diagnostic tests. To compare the performance of LPA and Xpert MTB/RIF assay for early diagnosis of rifampicin-resistant (RR) TB in acid-fast bacillus (AFB) smear-positive and negative sputum samples. Methods: A total 576 presumptive AFB patients were selected and subjected to AFB microscopy, Xpert MTB/RIF assay and recent version of LPA (GenoType MTBDRplus assay version 2) tests directly on sputum samples. Results were compared with phenotypic culture and drug susceptibility testing (DST). DNA sequencing was performed with rpoB gene for samples with discordant rifampicin susceptibility results. Results: Among culture-positive samples, Xpert MTB/RIF assay detected Mycobacterium tuberculosis (Mtb) in 97.3% (364/374) of AFB smear-positive samples and 76.5% (13/17) among smear-negative samples, and the corresponding values for LPA test (valid results with Mtb control band) were 97.9% (366/374) and 58.8% (10/17), respectively. For detection of RR among Mtb positive molecular results, the sensitivity of Xpert MTB/RIF assay and LPA (after resolving discordant phenotypic DST results with DNA sequencing) were found to be 96% and 99%, respectively. Whereas, specificity of both test for detecting RR were found to be 99%. Conclusion: We conclude that although Xpert MTB/RIF assay is comparatively superior to LPA in detecting Mtb among AFB smear-negative pulmonary TB. However, both tests are equally efficient in early diagnosis of AFB smear-positive presumptive RR-TB patients.

Metabolomic profiling of embryo culture media in patients with repeated implantation failure during assisted reproductive technology cycles

  • Sheyda Nami;Azam Govahi;Nabaa Najjar;Samaneh Ghasemi;Farshid Rezaei;Fatemehsadat Amjadi;Gholamreza Taheripak
    • Clinical and Experimental Reproductive Medicine
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    • v.51 no.3
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    • pp.260-267
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    • 2024
  • Objective: This study investigated the metabolic status of the spent culture media from embryos of patients with repeated implantation failure (RIF) undergoing in vitro fertilization-intracytoplasmic sperm injection cycles in comparison with the embryos from healthy fertile women. Methods: Metabolite levels in spent culture media were assessed and compared between embryos from RIF patients (n=35) and oocyte donors as controls (n=15). Protein levels of insulin-like growth factor 1 (IGF-1) were determined using Western blotting. Concentrations of glucose, pyruvate, and lactate were measured using spectrophotometry. Ionic colorimetric assay kits were utilized to analyze the concentrations of sodium, chloride, calcium, and magnesium ions. High-performance liquid chromatography was employed to measure the concentrations of glutamic acid, aspartic acid, methionine, phenylalanine, and histidine. Results: Glucose consumption and lactate secretion were higher in the control group than in the RIF group. The magnesium concentration was significantly higher in the control group than in the RIF group, but glutamic acid and aspartic acid concentrations were lower in the control group than in the RIF patients (p<0.05). The levels of IGF-1, sodium, calcium, chloride, methionine, histidine, and phenylalanine did not show statistically significant differences between the two groups. Conclusion: The metabolic profile of the culture medium of the embryos in the RIF group differed from that of the control group. These findings suggest potential factors that may affect implantation capacity in RIF patients and provide a new perspective on embryo selection.

Comparative Antimicrobial Susceptibility by the Methods of Test (검사방법(檢査方法)에 따르는 항균제감수성(抗菌劑感受性)의 비교(比較))

  • Park, Dong-Choon;Chun, Do-Ki
    • The Journal of the Korean Society for Microbiology
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    • v.13 no.1
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    • pp.43-48
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    • 1978
  • The difference in antimicrobial susceptibility of multiply drug-resistant Salmonella typhi by the methods of test was tested against chloramphenicol(Cm), tetracycline(Tc), ampicillin(Ap), kanamycin(Km), and rifampicin(Rif), and the results were compared by the minimum inhibitory concentration(MIC). No appreciable difference was noted between MICs of Cm, Tc, and Rif measured by agar plate dilution(plate) method and broth dilution(broth) method. However, MICs of Km to about a half of test strains were 4 to 8-fold higher by broth method than plate method, and MICs of Ap by broth method were also a little higher than plate method in some strains. Cm and Rif were bacteriostatic rather than bactericidal to the most of test strains in high concentrations. Tc, Ap and Km were exclusively bactericidal to the test strains.

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