Genetic associations of LYN with systemic lupus erythematosus

Lu, R,Vidal, G S,Kelly, J A,Delgado-Vega, A M,Howard, X K,Macwana, S R,Dominguez, N,Klein, W,Burrell, C,Harley, I T,Kaufman, K M,Bruner, G R,Moser, K L,Gaffney, P M,Gilkeson, G S,Wakeland, E K,Li, Q-Z Macmillan Publishers Limited 2009 GENES AND IMMUNITY Vol.10 No.5

We targeted LYN, a src-tyosine kinase involved in B-cell activation, in case–control association studies using populations of European-American, African-American and Korean subjects. Our combined European-derived population, consisting of 2463 independent cases and 3131 unrelated controls, shows significant association with rs6983130 in a female-only analysis with 2254 cases and 2228 controls (P=1.1 × 10<SUP>−4</SUP>, odds ratio (OR)=0.81 (95% confidence interval: 0.73–0.90)). This single nucleotide polymorphism (SNP) is located in the 5′ untranslated region within the first intron near the transcription initiation site of LYN. In addition, SNPs upstream of the first exon also show weak and sporadic association in subsets of the total European-American population. Multivariate logistic regression analysis implicates rs6983130 as a protective factor for systemic lupus erythematosus (SLE) susceptibility when anti-dsDNA, anti-chromatin, anti-52 kDa Ro or anti-Sm autoantibody status were used as covariates. Subset analysis of the European-American female cases by American College of Rheumatology classification criteria shows a reduction in the risk of hematological disorder with rs6983130 compared with cases without hematological disorders (P=1.5 × 10<SUP>−3</SUP>, OR=0.75 (95% CI: 0.62−0.89)). None of the 90 SNPs tested show significant association with SLE in the African American or Korean populations. These results support an association of LYN with European-derived individuals with SLE, especially within autoantibody or clinical subsets.Genes and Immunity (2009) 10, 397–403; doi:10.1038/gene.2009.19; published online 16 April 2009

Identification of prestress force in a prestressed Timoshenko beam

Z. R. Lu,J. K. Liu,S. S. Law 국제구조공학회 2008 Structural Engineering and Mechanics, An Int'l Jou Vol.29 No.3

This paper presents a new identification approach to prestress force. Firstly, a bridge deck is modeled as a prestressed Timoshenko beam. The time domain responses of the beam under sinusoidal excitation are studied based on modal superposition. The prestress force is then identified in the time domain by a system identification approach incorporating with the regularization of the solution. The orthogonal polynomial function is used to improve the noise effect and obtain the derivatives of modal responses of the bridge. Good identification results are obtained from only the first few measured modal data under both sinusoidal and impulsive excitations. It is shown that the proposed method is insensitive to the magnitude of force to be identified and can be successfully applied to indirectly identify the prestress force as well as other physical parameters, such as the flexural rigidity and shearing rigidity of a beam even under noisy environment.

State-space formulation for simultaneous identification of both damage and input force from response sensitivity

Lu, Z.R.,Huang, M.,Liu, J.K. Techno-Press 2011 Smart Structures and Systems, An International Jou Vol.8 No.2

A new method for both local damage(s) identification and input excitation force identification of beam structures is presented using the dynamic response sensitivity-based finite element model updating method. The state-space approach is used to calculate both the structural dynamic responses and the responses sensitivities with respect to structural physical parameters such as elemental flexural rigidity and with respect to the force parameters as well. The sensitivities of displacement and acceleration responses with respect to structural physical parameters are calculated in time domain and compared to those by using Newmark method in the forward analysis. In the inverse analysis, both the input excitation force and the local damage are identified from only several acceleration measurements. Local damages and the input excitation force are identified in a gradient-based model updating method based on dynamic response sensitivity. Both computation simulations and the laboratory work illustrate the effectiveness and robustness of the proposed method.

Mode localization and frequency loci veering in a disordered coupled beam system

Lu, Z.R.,Liu, J.K.,Huang, M. Techno-Press 2006 Structural Engineering and Mechanics, An Int'l Jou Vol.24 No.4

Vibration mode localization and frequency loci veering in disordered coupled beam system are studied in this paper using finite element analysis. Two beams coupled with transverse and rotational springs are examined. Small disorders in the physical parameters such as Young's modulus, mass density or span length of the substructure are introduced in the investigation of the mode localization and frequency loci veering phenomena. The effect of disorder in the elastic support on the mode localization phenomenon is also discussed. It is found that an asymmetric disorder in the weakly coupled system will lead to the occurrence of mode localization and frequency loci phenomena.

Identification of prestress force in a prestressed Timoshenko beam

Lu, Z.R.,Liu, J.K.,Law, S.S. Techno-Press 2008 Structural Engineering and Mechanics, An Int'l Jou Vol.29 No.3

This paper presents a new identification approach to prestress force. Firstly, a bridge deck is modeled as a prestressed Timoshenko beam. The time domain responses of the beam under sinusoidal excitation are studied based on modal superposition. The prestress force is then identified in the time domain by a system identification approach incorporating with the regularization of the solution. The orthogonal polynomial function is used to improve the noise effect and obtain the derivatives of modal responses of the bridge. Good identification results are obtained from only the first few measured modal data under both sinusoidal and impulsive excitations. It is shown that the proposed method is insensitive to the magnitude of force to be identified and can be successfully applied to indirectly identify the prestress force as well as other physical parameters, such as the flexural rigidity and shearing rigidity of a beam even under noisy environment.

Vibration analysis of a cracked beam with axial force and crack identification

Lu, Z.R.,Liu, J.K. Techno-Press 2012 Smart Structures and Systems, An International Jou Vol.9 No.4

A composite element method (CEM) is presented to analyze the free and forced vibrations of a cracked Euler-Bernoulli beam with axial force. The cracks are introduced by using Christides and Barr crack model with an adjustment on one crack parameter. The effects of the cracks and axial force on the reduction of natural frequencies and the dynamic responses of the beam are investigated. The time response sensitivities with respect to the crack parameters (i.e., crack location, crack depth) and the axial force are calculated. The natural frequencies obtained from the proposed method are compared with the analytical results in the literature, and good agreement is found. This study shows that the cracks in the beam may have significant effects on the dynamic responses of the beam. In the inverse problem, a response sensitivity-based model updating method is proposed to identify both a single crack and multiple cracks from measured dynamic responses. The cracks can be identified successfully even using simulated noisy acceleration responses.

Structural damage identification using incomplete static displacement measurement

Z. R. Lu,J.J. Zhu,Y.J. Ou 국제구조공학회 2017 Structural Engineering and Mechanics, An Int'l Jou Vol.63 No.2

A local damage identification method using measured structural static displacement is proposed in this study. Based on the residual force vector deduced from the static equilibrium equation, residual strain energy (RSE) is introduced, which can localize the damage in the element level. In the case of all the nodal displacements are used, the RSE can localize the true location of damage, while incomplete displacement measurements are used, some suspicious damaged elements can be found. A model updating method based on static displacement response sensitivity analysis is further utilized for accurate identification of damage location and extent. The proposed method is verified by two numerical examples. The results indicate that the proposed method is efficient for damage identification. The advantage of the proposed method is that only limited static displacement measurements are needed in the identification, thus it is easy for engineering application.

High-throughput integrated analyses for the tyrosinase-induced melanogenesis: microarray, proteomics and interactomics studies.

Lu, Z-R,Seo, E,Yan, L,Yin, S-J,Si, Y-X,Qian, G-Y,Park, Y-D,Yang, J-M Adenine Press 2010 Journal of biomolecular structure & dynamics Vol.28 No.2

<P>The tyrosinase gene was overexpressed in HEK293 cells, and then a DNA microarray and proteomic tools were applied to detect the dysregulated genes in highly pigmented cells. The candidate genes from the microarray were compared to the yeast two-hybridization results. Computational prediction via protein-protein interaction mapping suggested the existence of 66 hub genes in melanogenesis. Most importantly, RNA binding motif protein 9 is newly detected as a putative critical melanogenesis-associated gene in this study. The approach of combining the expression data analysis and predicted protein interaction partners performed in large scales can bring more reliable gene targets for understanding pigmentation.</P>

State-space formulation for simultaneous identification of both damage and input force from response sensitivity

Z.R. Lu,J.K. Liu,M. Huang 국제구조공학회 2011 Smart Structures and Systems, An International Jou Vol.8 No.2

A new method for both local damage(s) identification and input excitation force identification of beam structures is presented using the dynamic response sensitivity-based finite element model updating method. The state-space approach is used to calculate both the structural dynamic responses and the responses sensitivities with respect to structural physical parameters such as elemental flexural rigidity and with respect to the force parameters as well. The sensitivities of displacement and acceleration responses with respect to structural physical parameters are calculated in time domain and compared to those by using Newmark method in the forward analysis. In the inverse analysis, both the input excitation force and the local damage are identified from only several acceleration measurements. Local damages and the input excitation force are identified in a gradient-based model updating method based on dynamic response sensitivity. Both computation simulations and the laboratory work illustrate the effectiveness and robustness of the proposed method.

Structural damage detection based on residual force vector and imperialist competitive algorithm

Z.H. Ding,R.Z. Yao,J.L. Huang,M. Huang,Z. R. Lu 국제구조공학회 2017 Structural Engineering and Mechanics, An Int'l Jou Vol.62 No.6

This paper develops a two-stage method for structural damage identification by using modal data. First, the Residual Force Vector (RFV) is introduced to detect any potentially damaged elements of structures. Second, data of the frequency domain are used to build up the objective function, and then the Imperialist Competitive Algorithm (ICA) is utilized to estimate damaged extents. ICA is a heuristic algorithm with simple structure, which is easy to be implemented and it is effective to deal with high-dimension nonlinear optimization problem. The advantages of this present method are: (1) Calculation complexity can be decreased greatly after eliminating many intact elements in the first step. (2) Robustness, ICA ensures the robustness of the proposed method. Various damaged cases and different structures are investigated in numerical simulations. From these results, anyone can point out that the present algorithm is effective and robust for structural damage identification and is also better than many other heuristic algorithms.