A framework for computer vision-based health monitoring of a truss structure subjected to unknown excitations

Computer vision(CV)methods for measurement of structural vibration are less expensive,and their application is more straightforward than methods based on sensors that measure physical quantities at particular points of a structure.However,CV methods produce significantly more measurement errors.Thus,computer vision-based structural health monitoring(CVSHM)requires appropriate methods of damage assessment that are robust with respect to highly contaminated measurement data.In this paper a complete CVSHM framework is proposed,and three damage assessment methods are tested.The first is the augmented inverse estimate(AIE),proposed by Peng et al.in 2021.This method is designed to work with highly contaminated measurement data,but it fails with a large noise provided by CV measurement.The second method,as proposed in this paper,is based on the AIE,but it introduces a weighting matrix that enhances the conditioning of the problem.The third method,also proposed in this paper,introduces additional constraints in the optimization process;these constraints ensure that the stiffness of structural elements can only decrease.Both proposed methods perform better than the original AIE.The latter of the two proposed methods gives the best results,and it is robust with respect to the selected coefficients,as required by the algorithm.

Correlations between skin lesions induced by anti-tumor necrosis factor-α and selected cytokines in Crohn's disease patients

AIM:To investigate the correlation between the appearance of skin lesions and concentration of interleukin(IL)-17A,IL-23 and interferon-γ(IFN-γ)in Crohn’s disease(CD)patients during anti-tumor necrosis factor-α(TNF-α)therapy METHODS:A prospective study included 30 adult patients with CD of Caucasian origin(19 men and 11women;mean age±SD 32.0±8.6 years)during biological therapy with anti-TNF-αantibodies from January2012 to March 2013.Eighteen patients were treated with infliximab,seven with adalimumab and five withcertolizumab.Inclusion criteria were exacerbation of the underlying disease,Crohn’s Disease Activity Index over 300 and the ineffectiveness of previously used non-biological therapies.Patients with a history of psoriasis,atopic dermatitis and other autoimmune skin lesions were excluded from the study.The control group consisted of 12 healthy subjects.A diagnostic survey was carried out,blood tests and careful skin examination were performed,and the serum levels of IL-17,IL-23 and IFN-γwere measured using an enzyme-linked immunosorbent assays technique.Dermatoses that have developed in the course of biological therapy in patients who had no pre-existing skin lesions of similar character were qualified as skin lesions induced by antiTNF-αtherapy.RESULTS:Skin manifestations occurred in 18 of CD patients during the anti-TNF-αtherapy(60%),in the average time of 10.16±3.42 mo following the beginning of the 52-wk treatment cycle.Skin lesions observed in CD patients during biological therapy included psoriasiform lesions(44.4%),and eczema forms lesions(22.2%).In CD patients with drug induced skin lesions significantly higher levels of hemoglobin(13.3±1.5 g/dL vs 10.8±1.9 g/dL,P=0.018)and hematocrit(39.9%±4.5%vs 34.3%±5.4%,P=0.01),as well as a significantly lower level of platelets(268±62×103/μL vs 408±239×103/μL,P=0.046)was observed compared with CD patients without skin manifestations.The concentrations of IL-17A and IL-23in CD patients with skin lesions developed under antiTNF-αtherapy were significantly higher compared to those in patients without lesions(IL-17A:39.01±7.03pg/mL vs 25.71±4.90 pg/mL,P=0.00004;IL-23:408.78±94.13 pg/mL vs 312.15±76.24 pg/mL,P=0.00556).CONCLUSION:Skin lesions in CD patients during bio-logical therapy may result from significantly increased concentrations of IL-17A and IL-23,which are strongly associated with TNF-α/Th1 immune pathways.