Role of folP1 and folP2 Genes in the Action of Sulfamethoxazole and Trimethoprim Against Mycobacteria

( Tian Zhou Liu ),( Bang Xing Wang ),( Jin Tao Guo ),( Yang Zhou ),( Mugweru Julius ),( Moses Njire ),( Yuan Yuan Cao ),( Tian Wu ),( Zhi Yong Liu ),( Chang Wei Wang ),( Yong Xu ),( Tian Yu Zhang ) 한국미생물 · 생명공학회 2015 Journal of microbiology and biotechnology Vol.25 No.9

The combination of trimethoprim (TMP) and sulfamethoxazole (SMX) has been shown to be active against Mycobacterium tuberculosis (Mtb) in clinical tuberculosis (TB) treatment. However, the mechanism of action of TMP-SMX against Mtb is still unknown. To unravel this, we have studied the effect of TMP and SMX by deleting the folP2 gene in Mycobacterium smegmatis (Msm), and overexpressing the Mtb and Msm folP1/2 genes in Msm. Knocking out of the folP2 gene in Msm reduced the minimum inhibitory concentration of SMX 8-fold compared with wild type. Overexpression of the folP1 genes from Mtb and Msm increased the MICs by 4- and 2-fold in Msm for SMX and TMP, respectively. We show a strong correlation between the expression of folP1 and folP2 genes and TMP-SMX resistance in mycobacteria. This suggests that a combination of FolP2 inhibitor and SMX could be used for TB treatment with a better outcome.

A Review on Bioactive Compounds from Marine-Derived Chaetomium Species

( Yuan Tian ),( Yanling Li ) 한국미생물생명공학회 2022 Journal of microbiology and biotechnology Vol.32 No.5

Filamentous marine fungi have proven to be a plentiful source of new natural products. Chaetomium, a widely distributed fungal genus in the marine environment, has gained much interest within the scientific community. In the last 20 years, many potential secondary metabolites have been detected from marine-derived Chaetomium. In this review, we attempt to provide a comprehensive summary of the natural products produced by marine-derived Chaetomium species. A total of 122 secondary metabolites that were described from 2001 to 2021 are covered. The structural diversity of the compounds, along with details of the sources and relevant biological properties are also provided, while the relationships between structures and their bioactivities are discussed. It is our expectation that this review will be of benefit to drug development and innovation.

A Privacy-aware Graph-based Access Control System for the Healthcare Domain

( Yuan Tian ),( Biao Song ),( M. Mehedi. Hassan ),( Eui-nam Huh ) 한국인터넷정보학회 2012 KSII Transactions on Internet and Information Syst Vol.6 No.10

The growing concern for the protection of personal information has made it critical to implement effective technologies for privacy and data management. By observing the limitations of existing approaches, we found that there is an urgent need for a flexible, privacy-aware system that is able to meet the privacy preservation needs at both the role levels and the personal levels. We proposed a conceptual system that considered these two requirements: a graph-based, access control model to safeguard patient privacy. We present a case study of the healthcare field in this paper. While our model was tested in the field of healthcare, it is generic and can be adapted to use in other fields. The proof-of-concept demos were also provided with the aim of valuating the efficacy of our system. In the end, based on the hospital scenarios, we present the experimental results to demonstrate the performance of our system, and we also compared those results to existing privacy-aware systems. As a result, we ensured a high quality of medical care service by preserving patient privacy.

Using Frequency Scaling on Virtualized Memory in Cloud Datacenters

Yuan Tian,Ze Xiao 보안공학연구지원센터 2016 International Journal of Grid and Distributed Comp Vol.9 No.9

As the increasing of IT-infrastructure in cloud platforms, rapidly growth of energy consumption becomes a critical problem in many cloud datacenters. Conventionally, most of studies on energy-efficiency optimization concentrate on CPU related energy costs instead of memory subsystem, since CPU often dominates the total energy consumption in modern servers. However, such a situation is gradually changing as more and more cloud datacenters are equipped with larger and larger memory systems for dealing with data-intensive applications. In this paper, we present a novel mechanism, namely frequency scaling on virtualized memory (FSVM), which applies DVFS technology on memory subsystem based on the characteristics of active VM instances. Comparing with previous studies, our approach provides a fine-grained memory energy consumption conservation mechanism for virtualized servers. Extensive experiments are conducted to investigate the effectiveness and performance of our FSVM, and the results indicate that it can significantly improve the energy-efficiency of memory subsystem in virtualized servers.

Performance Analysis of Detection Threshold on OFDM Time Synchronization Using PN Sequences

Yuan Tian,Xia Lei,Wanbin Tang,Shaoqian Li 보안공학연구지원센터 2008 International Journal of Software Engineering and Vol.2 No.3

Many synchronization algorithms for orthogonal frequency division multiplexing (OFDM) systems have been proposed. Among them, the time synchronization algorithm by correlating the training sequence with the local known sequence can obtain good performance with a sharp synchronization peak. Detection threshold is an important and necessary parameter in time synchronization. In this paper, based on this algorithm, we evaluate three different methods of setting threshold and point out one method which performs well when SNR is in large dynamic range. The simulation results are consonant with our theoretic analyses and show that this method is suitable for OFDM systems in multi-path fading channel.

HETEROGENEITY EFFECTS OF DEVELOPMENT FUNDING ON MICROENTERPRISES

YUAN TIAN 중앙대학교 경제연구소 2015 Journal of Economic Development Vol.40 No.3

This paper focuses on the heterogeneity of firm’s characteristics on development funding. It develops a theoretical model under utility maximization framework with imperfect insurance and credit markets constraints, deriving the returns to capital determined by firm’s size, structure and entrepreneur’s utility form. Empirical evidence from Sri Lanka Microenterprises Project (2005-2010) shows that the returns vary across different quantiles of firm’s profits and the ability/risk aversion of entrepreneur affects the returns significantly differently on the distribution of profits. It also summarizes the development funding policy and offers advice on policy evaluation in Sri Lanka.

Liposome-mediated Induction of Apoptosis of Human Hepatoma Cells by C-Myc Antisense Phosphorothioate Oligodeoxynucleotide and 5-Fluorouracil

Yuan, Yuan,Cai, Hui,Yang, Xiao-Jun,Li, Wei,He, Jin,Guo, Tian-Kang,Chen, Yi-Rong Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.14

Background: The aim of this study was to investigate the effect of a c-myc antisense oligodeoxynucleotide and 5-fluorouracil on the expression of c-myc, invasion and proliferation of HEPG-2 liver cancer cells. Materials and Methods: HEPG-2 cells were treated with lipiosome-mediated c-myc ADSON and 5-fluorouracil. The proliferation inhibition rate and invasion were measured by MTT and invasion assay, respectively. Cell apoptosis was detected by flow cytometry and expression of c-myc by RT-PCR and immunohistochemistry. Results: The proliferation inhibition rate was significantly higher in the antisense oligodeoxynucleotide added-5-fluorouracil group than single antisense oligodeoxynucleotide or 5-fluorouracil group (p<0.05). G0/G1 cells in the antisense oligodeoxynucleotide group and S cells in the 5-fluorouracil groups were significantly increased than that in the control group, respectively (P<0.01). The amplification strips of PCR products in 5-FU, ASODN and combination groups were significantly weaker than that in the control group (P<0.01). The percentage of c-myc-protein-positive cells were significantly lower in antisense oligodeoxynucleotide, 5-fluorouracil and combination groups than that in the control group (P<0.01). Conclusions: A liposome-mediated c-myc antisense oligodeoxynucleotide and 5-fluorouracil can inhibit the proliferation and invasion of liver cancer cells by reducing the expression of c-myc. A c-myc antisense oligodeoxynucleotide can increase the sensitivity of liver cancer cells to 5-fluorouracil and decrease the dosage of the agent necessary for efficacy, providing an experimental basis for the clinical therapy of liver cancer.

Shear Capacity Contribution of Steel Fiber Reinforced High-Strength Concrete Compared with and without Stirrup

Tian-Feng Yuan,Doo-Yeol Yoo,Jun-Mo Yang,Young-Soo Yoon 한국콘크리트학회 2020 International Journal of Concrete Structures and M Vol.14 No.3

This study presents the shear capacity of eco-friendly high-strength concrete (HSC) beams reinforced by 0.75% (by volume) of hooked steel fibers or shear stirrups with various spacings. Five large-scale HSC beams with steel fibers or stirrups were tested and investigated with respect to shear capacity, failure mode, and crack patterns. The test results indicate that all five tested beams finally failed by a shear-critical failure mode and that the use of 0.75 vol% of steel fibers significantly improved the shear strength although it decreased the diagonal crack angle of HSC beam in the case of without stirrups. There are some different properties compared with ACI 318-19 recommendation, but the use of 0.75 vol% steel fibers exhibited approximately 13.2% higher shear strength when compared with that of minimum shear reinforcement for the HSC beam. Furthermore, the shear capacity of steel fibers calculated by experimental data, and it was compared with several prediction equations. The prediction models containing fiber factor were more closely agreeable with test results with a minimum of 10.9% difference.

Assessment of Steel Slag and Steel Fiber to Control Electromagnetic Shielding in High-Strength Concrete

Tian-Feng Yuan,Jin-Seok Choi,Seong-Kyum Kim,Young-Soo Yoon 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.3

This study investigates the influence of steel slag (SS) and steel fibers on the electrical resistivity and electromagnetic (EM) shielding effectiveness of high-strength concrete (HSC). It was found that the electrical resistivity of mixtures were mainly influenced by free water. Thus, the EM shielding effectiveness was evaluated without the effect of free water. HSC with 20% replacement ratio of SS exhibited slightly improved EM shielding, lower electrical resistivity, and reduced strength (compressive and flexural) compared to HSC without SS. However, HSC with steel fibers exhibited significantly improved EM shielding, lower electrical resistivity, and higher strength and toughness compared to HSC without steel fibers. An increase in the steel fiber content in the HSC significantly decreased the electrical resistivity and increased the shielding effectiveness, strength, and toughness. Regardless of the fiber content in the fiber volume fraction of mixture, the shielding effectiveness is similar for cases with and without SS whose electrical resistivity values differ only slightly. This proves that the EM shielding effectiveness was mainly affected by the electrical resistivity and these properties are significantly correlated when the electrical resistivity values differ noticeably. HSC reinforced with rebar with 50 mm spacing exhibited a 23.5 − 75.6% increase in the shielding effectiveness in the 600 − 1,000 MHz frequency region compared to pristine HSC.

Experimental Investigation on Mechanical Properties of Hybrid Steel and Polyethylene Fiber-Reinforced No-Slump High-Strength Concrete

Yuan, Tian-Feng,Lee, Jin-Young,Min, Kyung-Hwan,Yoon, Young-Soo Hindawi Limited 2019 International journal of polymer science Vol.2019 No.-

<P>This paper presents experimental investigations on the mechanical properties of no-slump high-strength concrete (NSHSC), such as the compressive and flexural strength. First, to determine the proper NSHSC mixtures, the compressive and flexural strength of three different water-to-binder ratios (w/b) of specimens with and without polyethylene (PE) fiber was tested at test ages. Then, the effect of hybrid combinations of PE fiber and steel fiber (SF) on the compressive strength, flexural strength, flexural toughness, and flexural energy dissipation capacity was experimentally investigated. Furthermore, the various hybrid fiber-reinforced NSHSCs were evaluated, and their synergy was calculated, after deriving the benefits from each of the individual fibers to exhibit a synergetic response. The test results indicate that a w/b of 16.8% with or without fibers had lower strength and flexural strength (toughness) than those of other mixtures (w/b of 16.4% and 17.2%). Specimens with a hybrid of SF and short PE fibers exhibited a higher compressive and flexural strength, flexural toughness, energy dissipation capacity, and fiber synergy in all considered instances.</P>