Quorum Sensing and Quorum-Quenching Enzymes

Dong, Yi-Hu,Zhang, Lian-Hui The Microbiological Society of Korea 2005 The journal of microbiology Vol.43 No.1

To gain maximal benefit in a competitive environment, single-celled bacteria have adopted a community genetic regulatory mechanism, known as quorum sensing (QS). Many bacteria use QS signaling systems to synchronize target gene expression and coordinate biological activities among a local population. N-acylhomoserine lactones (AHLs) are one family of the well-characterized QS signals in Gram-negative bacteria, which regulate a range of important biological functions, including virulence and biofilm formation. Several groups of AHL-degradation enzymes have recently been identified in a range of living organisms, including bacteria and eukaryotes. Expression of these enzymes in AHL-dependent pathogens and transgenic plants efficiently quenches the microbial QS signaling and blocks pathogenic infections. Discovery of these novel quorum quenching enzymes has not only provided a promising means to control bacterial infections, but also presents new challenges to investigate their roles in host organisms and their potential impacts on ecosystems.

LES of wind environments in urban residential areas based on an inflow turbulence generating approach

Lian Shen,Yan Han,C.S. Cai,Guochao Dong,Jianren Zhang,Peng Hu 한국풍공학회 2017 Wind and Structures, An International Journal (WAS Vol.24 No.1

Wind environment in urban residential areas is an important index to consider when evaluating the living environment. However, due to the complexity of the flow field in residential areas, it is difficult to specify the correct inflow boundary conditions in the large eddy simulation (LES). In this paper, the weighted amplitude wave superposition (WAWS) is adopted to simulate the fluctuating velocity data, which satisfies the desired target wind field. The fluctuating velocity data are given to the inlet boundary of the LES by developing an UDF script, which is implemented into the FLUENT. Then, two numerical models - the empty numerical wind tunnel model and the numerical wind tunnel model with spires and roughness elements are established based on the wind tunnel experiment to verify the present method. Finally, the turbulence generation approach presented in this paper is used to carry out a numerical simulation on the wind environment in an urban residential area in Lisbon. The computational results are compared with the wind tunnel experimental data, showing that the numerical results in the LES have a good agreement with the experimental results, and the simulated flow field with the inlet fluctuations can generate a reasonable turbulent wind field. It also shows that strong wind velocities and turbulent kinetic energy occur at the passageways, which may affect the comfort of people in the residential neighborhood, and the small wind velocities and vortexes appear at the leeward corners of buildings, which may affect the spreading of the pollutants.

Optimization of the construction scheme of the cable-strut tensile structure based on error sensitivity analysis

Lian-meng Chen,Dong Hu,Hua Deng,Yu-hong Cui,Yi-yi Zhou 국제구조공학회 2016 Steel and Composite Structures, An International J Vol.21 No.5

Optimization of the construction scheme of the cable-strut tensile structure based on error sensitivity analysis is studied in this paper. First, the element length was extracted as a fundamental variable, and the relationship between element length change and element internal force was established. By setting all pre-stresses in active cables to zero, the equation between the pre-stress deviation in the passive cables and the element length error was obtained to analyze and evaluate the error effects under different construction schemes. Afterwards, based on the probability statistics theory, the mathematical model of element length error is set up. The statistical features of the pre-stress deviation were achieved. Finally, a cable-strut tensile structure model with a diameter of 5.0 m was fabricated. The element length errors are simulated by adjusting the element length, and each member in one symmetrical unit was elongated by 3 mm to explore the error sensitivity of each type of element. The numerical analysis of error sensitivity was also carried out by the FEA model in ANSYS software, where the element length change was simulated by implementing appropriate temperature changes. The theoretical analysis and experimental results both indicated that different elements had different error sensitivities. Likewise, different construction schemes had different construction precisions, and the optimal construction scheme should be chosen for the real construction projects to achieve lower error effects, lower cost and greater convenience.

Determination of a Monitoring Scheme for Controlling Construction Errors of a Cable-strut Tensile Structure

Lian-meng Chen,Wei-feng Gao,Dong Hu,Yi-yi Zhou,Fu-bo Zhang,Shi-lin Dong 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.10

Construction errors are inevitable in real cable-strut tensile structures. Nevertheless, the relevant work, especially the monitoring scheme design work, to control the construction errors is lacking. At present, the monitoring schemes always lay out the monitored members in the places with great internal force or great deformation, do not consider the method to control the construction errors and do not explain the method to lay out the monitored members in fundamental theory. To address this situation, the element length error, which is an important construction error affecting the bearing performance, is considered as the factor variable and the fundamental equation of pre-stress deviation and element length error is derived firstly. Next the methods to express the pre-stress deviation, which are only derived from the active cable length errors or from both the active cable and passive cable length errors, are discussed. After that, based on the condition that the errors can be solved and compensated, the least number of monitored members is determined. Moreover, those members sensitive to cable length deviation of active cables are selected as monitored members. In order to evaluate the effect level caused by passive cable length deviation, two evaluation parameters Δ and ρ are further discussed. Finally, one cable-strut tensile structure example is employed to verify the proposed method and the results of the example studies indicate that the least necessary number of monitored members can be achieved for the accurate solution and compensation of active cable length deviations. Different members have different sensitivities to the change of the length in active cables and those members with great sensitivities can be chosen in prior as monitored members. The evaluation parameters Δ and ρ can be used to analyze the source of errors and to evaluate the error effect level caused by the passive cable length deviation.

High­risk human papillomavirus genotype distribution and attribution to cervical cancer and precancerous lesions in a rural Chinese population

Xue-Lian Zhao,Shang-Ying Hu,Qian Zhang,Li Dong,Rui-Mei Feng,Ross Han,Fang-Hui Zhao 대한부인종양학회 2017 Journal of Gynecologic Oncology Vol.28 No.4

Objective: To explore the genotype distribution of high-risk human papillomavirus (HR-HPV) and its attribution to different grades of cervical lesions in rural China, which will contribute to type-specific HPV screening tests and the development of new polyvalent HPV vaccines among the Chinese population. Methods: One thousand two hundred ninety-two subjects were followed based on the Shanxi Province Cervical Cancer Screening Study I (SPOCCS-I), and screened by HPV DNA testing (hybrid capture® 2 [HC2]), liquid-based cytology (LBC), and if necessary, directed or random colposcopy-guided quadrant biopsies. HPV genotyping with linear inverse probe hybridization (SPF10-PCR-LiPA) was performed in HC2 positive specimens. Attribution of specific HR-HPV type to different grades of cervical lesions was estimated using a fractional contribution approach. Results: After excluding incomplete data, 1,274 women were included in the final statistical analysis. Fifteen point two percent (194/1,274) of women were HR-HPV positive for any of 13 HR-HPV types (HPV16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, and 68) and the most common HR-HPV types were HPV16 (19.1%) and HPV52 (16.5%). The genotypes most frequently detected in HR-HPV-positive cervical intraepithelial neoplasia grade 1 (CIN1) were HPV52 (24.1%), HPV31 (20.7%), HPV16 (13.8%), HPV33 (13.8%), HPV39 (10.3%), and HPV56 (10.3%); in HR-HPV-positive cervical intraepithelial neoplasia grade 2 or worse (CIN2+): HPV16 (53.1%), HPV58 (15.6%), HPV33 (12.5%), HPV51 (9.4%), and HPV52 (6.3%). HPV52, 31, 16, 33, 39, and 56 together contributed to 89.7% of HR-HPV-positive CIN1, and HPV16, 33, 58, 51, and 52 together contributed to 87.5% of CIN2+. Conclusion: In summary, we found substantial differences in prevalence and attribution of CINs between different oncogenic HPV types in a rural Chinese population, especially for HPV16, 31, 33, 52, and 58. These differences may be relevant for both clinical management and the design of preventive strategies.

Case-control study on the fibroblast growth factor receptor 2 gene Polymorphisms associated with breast cancer in in Chinese Han women

Chun-Lian Liu,Xiao-Ping Hu,Wei-Dong Guo,Li Yang,Jie Dang,Hai-Yan Jiao 한국유방암학회 2013 Journal of breast cancer Vol.16 No.4

Purpose: Genetic variation in fibroblast growth factor receptor 2(FGFR2) is a newly described risk factor for breast cancer. Thisstudy aimed to evaluate the association of four single nucleotidepolymorphisms (SNPs) in FGFR2 with breast cancer in Han Chinesewomen. Methods: Two hundred three women with breastcancer and 200 breast cancer-free age-matched controls wereselected. Four SNPs (rs2981579, rs1219648, rs2420946, andrs2981582) and their haplotypes were analyzed to test for theirassociation with breast cancer susceptibility. The presence ofthe four FGFR2 SNPs was determined by polymerase chain reaction-restriction fragment length polymorphism analysis. Results:A statistically significant difference was observed in thefrequency of rs2981582 in the FGFR2 gene (p<0.05) betweencase and control groups. In subjects stratified by menopausalstatus, rs2981582 TT, rs2420946 AA, and rs1219648 CC weresignificantly associated with the risk of breast cancer in postmenopausalsubjects, but no significant associations betweenthese four SNPs and the risk of breast cancer were identified inpremenopausal subjects. Further, there was no significant associationbetween hormone receptor status (estrogen receptor andprogesterone receptor) and breast cancer risk. Six common (>3%) haplotypes were identified. Three of these haplotypes,CGTC (odds ratio [OR], 0.613; 95% confidence interval [CI],0.457-0.82; p=0.001), TGTC (OR, 6.561; 95% CI, 2.064-20.854;p<0.001), and CATC (OR, 12.645; 95% CI, 1.742-91.799; p=0.001) were significantly associated with breast cancer risk. Conclusion:Our findings indicated that the SNP rs2981582 and haplotypesCGTC, TGTC, and CATC in FGFR2 may be associatedwith an increased risk of breast cancer in Han Chinese women.

LES of wind environments in urban residential areas based on an inflow turbulence generating approach

Shen, Lian,Han, Yan,Cai, C.S.,Dong, Guochao,Zhang, Jianren,Hu, Peng Techno-Press 2017 Wind and Structures, An International Journal (WAS Vol.24 No.1

Wind environment in urban residential areas is an important index to consider when evaluating the living environment. However, due to the complexity of the flow field in residential areas, it is difficult to specify the correct inflow boundary conditions in the large eddy simulation (LES). In this paper, the weighted amplitude wave superposition (WAWS) is adopted to simulate the fluctuating velocity data, which satisfies the desired target wind field. The fluctuating velocity data are given to the inlet boundary of the LES by developing an UDF script, which is implemented into the FLUENT. Then, two numerical models - the empty numerical wind tunnel model and the numerical wind tunnel model with spires and roughness elements are established based on the wind tunnel experiment to verify the present method. Finally, the turbulence generation approach presented in this paper is used to carry out a numerical simulation on the wind environment in an urban residential area in Lisbon. The computational results are compared with the wind tunnel experimental data, showing that the numerical results in the LES have a good agreement with the experimental results, and the simulated flow field with the inlet fluctuations can generate a reasonable turbulent wind field. It also shows that strong wind velocities and turbulent kinetic energy occur at the passageways, which may affect the comfort of people in the residential neighborhood, and the small wind velocities and vortexes appear at the leeward corners of buildings, which may affect the spreading of the pollutants.

Study of Indoor Positioning Method Based on Combination of Support Vector Regression and Kalman Filtering

Yu Zhang,Lian Dong,Lei Lai,Lizhi Hu 보안공학연구지원센터 2016 International Journal of Future Generation Communi Vol.9 No.3

Estrogen Receptor Alpha Gene Polymorphisms and Breast Cancer Risk: a Case-control Study with Meta-analysis Combined

Lu, Hong,Chen, Dong,Hu, Li-Ping,Zhou, Lian-Lian,Xu, Hui-Ying,Bai, Yong-Heng,Lin, Xiang-Yang Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.11

Molecular epidemiological studies have shown that gene polymorphisms of estrogen receptor alpha gene (ESR-${\alpha}$) are associated with breast cancer risk. However, previous results from many molecular studies have been inconsistent. In this study, we examined two polymorphisms (PvuII and XbaI RFLPs) of the ESR-${\alpha}$ gene in 542 breast cancer cases and 1,016 controls from China. Associations between the polymorphisms and breast cancer risk were calculated with an unconditional logistic regression model. Linkage disequilibrium and haplotypes were analyzed with the SHEsis software. In addition, we also performed a systematic meta-analysis of 24 published studies evaluating the association. No significant associations were found between the PvuII polymorphism and breast cancer risk. However, a significantly decreased risk of breast cancer was observed among carriers of the XbaI 'G' allele (age-adjusted OR = 0.80; 95% CI = 0.66- 0.97) compared with carriers of the 'A' allele. Haplotype analysis showed significantly decreased cancer risk for carriers of the 'CG' haplotype (OR = 0.79; 95% CI = 0.66- 0.96). In the systematic meta-analysis, the XbaI 'G' allele was associated with an overall significantly decreased risk of breast cancer (OR = 0.90, 95% CI = 0.82- 1.00). In addition, the PvuII 'C' allele showed a 0.96- fold decreased disease risk (95% CI = 0.92- 0.99). In subgroup analysis, an association between the PvuII 'C' and XbaI 'G' alleles and breast cancer risk was significant in Asians ('C' vs. 'T': OR = 0.93, 95% CI = 0.85- 1.00; 'G' vs. 'A': OR = 0.82, 95% CI = 0.68- 0.98), but not in Euro-Americans. Thus, our results provide evidence that ESR-${\alpha}$ polymorphisms are associated with susceptibility to breast cancer. These associations may largely depend on population characteristics and geographic location.

Regulatory effect of peroxiredoxin 1 (PRDX1) on doxorubicin-induced apoptosis in triple negative breast cancer cells

Han Ying-Hao,Lian Xu-Dong,Lee Seung-Jae,Li Wei-Long,Sun Hu-Nan,Jin Mei-Hua,Kwon Taeho 한국응용생명화학회 2022 Applied Biological Chemistry (Appl Biol Chem) Vol.65 No.5

Patients with triple negative breast cancer (TNBC) lack the estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2; thus, conventional hormone and targeted therapies have minimal effect on them. Therefore, clinical treatment of TNBC is still based on chemotherapy and supplemented by other methods. Doxorubicin (DOX), a common drug used in TNBC chemotherapy, has high affinity for cardiolipin, and the nematosomes are rich in cardiolipin; therefore, DOX has high mitochondria-targeting ability. DOX accumulates and plunders the electrons of nicotinamide adenine dinucleotide phosphate (NADPH) and cytochrome C in mitochondria to produce semiquinone DOX. Under the action of oxygen molecules, semiquinone DOX is reduced to DOX and reactive oxygen species (ROS) are generated. The accumulation of ROS can cause mitochondrial dysfunction and lead to mitochondrial dependent apoptosis. Bioinformatic analysis of samples from TNBC patients revealed that peroxiredoxin 1 (PRDX1) was highly expressed in TNBC tissues, and the poor prognosis of patients with high PRDX1 expression was considerably increased. Previous studies determined that DOX can upregulate the expression of the PRDX1 protein in the human TNBC cell line (MDA-MB-231). Thus, we speculate that PRDX1 plays an important role in the process of DOX-induced TNBC cell apoptosis. In this study, we aimed to explore the role of PRDX1 in the process of DOX-induced TNBC cell apoptosis. We found that PRDX1 deletion increased the sensitivity of MDA-MB-231 cells to DOX, which was mainly due to mitochondrial oxidative stress caused by intracellular ROS accumulation, leading to mitochondriadependent apoptosis. Deletion of PRDX1 promotes the PI3K/Akt signaling pathway to mediate the expression of GSK3β. Gsk3β is an upstream signal of mitochondria-dependent apoptosis, and is also an important target of ROS. PRDX1 participates in adriamycin-induced apoptosis of TNBC cells by regulating the expression level of GSK3β. Our findings present new insights to treat breast cancer and TNBC, outlines the clinical use of DOX, and provides a basic theory to develop PRDX1 gene function.