488 research outputs found
Oxidative stress and inflammation biomarkers in pulmonary tuberculosis
Background: Tuberculosis outcome and clinical features of the infection are influenced by the degree of the multiplication of mycobacterias, host’s defense mechanisms and the organism’s capacity to fight through the antioxidant mechanisms against the aggression of the oxidative stress. The aim of the study was to assess the oxidative stress and inflammatory biomarkers in pulmonary tuberculosis.
Material and methods: A prospective study, which included 46 patients with pulmonary tuberculosis and 36 healthy persons determined according to the clinical and biochemical criteria, was performed. The oxidative stress was assessed through the level of the advanced oxidation protein products, advanced glycation end-products, fibrinogen, amino acid catabolic products, activity of N-acetyl-β-D-glucosaminidase. The determination of the total antioxidant activity of plasma was performed through ABTS and CUPRAC methods. IL-8 and TNF-α were assessed using analysis kits of BOSTER (USA) producer.
Results: Was established high level of the oxidative stress following the assessment of the concentration of the advanced oxidation protein products, advanced glycation end-products, fibrinogen, N-acetyl-β-D-glucosaminidase, urea and creatinine. High concentration of amino acid catabolic products was attributed to the nephrotoxic properties of the medication. Was identified high level of the plasma total antioxidant activity and antioxidant compounds. Cytokines concentration IL-8 and TNF-α was several times higher than in the control group and they were assessed as specific biomarkers.
Conclusions: High level of the protein peroxidation, advanced glycation end-products, fibrinogen, protein catabolism compounds, pro-inflammatory cytokines – IL-8 and TNF-α confirmed the boosting of the oxidative stress. The elevated total antioxidant activity and antioxidant proteins demonstrated the organism’s capacity to redress the oxidative aggression
The Method of Fundamental Solutions for Direct Cavity Problems in EIT
The Method of Fundamental Solutions (MFS) is an effective technique for solving linear elliptic partial differential equations, such as the Laplace and Helmholtz equation. It is a form of indirect boundary integral equation method and a technique that uses boundary collocation or boundary fitting. In this paper the MFS is implemented to solve A numerically an inverse problem which consists of finding an unknown cavity within a region of interest based on given boundary Cauchy data. A range of examples are used to demonstrate that the technique is very effective at locating cavities in two-dimensional geometries for exact input data. The technique is then developed to include a regularisation parameter that enables cavities to be located accurately and stably even for noisy input data
Level of cytokines in patients with pulmonary drug susceptible and resistant tuberculosis
Department of Pneumophthisiology, Nicolae Testemitsanu State University of Medicine and Pharmacy, Chisinau, the Republic of MoldovaBackground: Cytokines are the regulators of the immune response in tuberculosis: TNF-alpha and CXCL8 (IL-8) are involved in the granuloma formation, IL-10 inhibits the inflammation; some chemokines increase the liver production of the acute phase proteins (APPs). The aim of the research was to assess the serum level of IL-8, TNF-alpha, IL-10, C-reactive protein (CRP), ceruloplasmin and fibrinogen in patients with drug-sensitive and multidrug resistant tuberculosis (MDR-TB). Material and methods: A prospective case-control study, which included 51 patients, distributed in 2 groups: the 1st study group (N=24 new cases with drug-sensitive TB) and the 2nd study group (N=27 new cases with MDR-TB) according to sex and age were compared with the control group (N=36 healthy individuals). Results: Serum concentration of IL-8 was elevated up to 13 times, TNF-alpha up to 4 times and IL-10 up to 2 times in study groups, compared with the reference value of the control group. Fibrinogen concentration was elevated up to 2 times in study groups compared with the control group and CRP up to 3 times compared with conventional value. Ceruloplasmin was statistically higher in the drug-sensitive TB and mildly elevated in MDR-TB group. Conclusions: Proinflammatory biomarkers are more elevated than the anti-inflammatory response, without differences among groups regarding drug sensitivenes
The method of fundamental solutions for the Oseen steady‐state viscous flow past obstacles of known or unknown shapes
In this paper, the steady‐state Oseen viscous flow equations past a known or unknown obstacle are solved numerically using the method of fundamental solutions (MFS), which is free of meshes, singularities, and numerical integrations. The direct problem is linear and well‐posed, whereas the inverse problem is nonlinear and ill‐posed. For the direct problem, the MFS computations of the fluid flow characteristics (velocity, pressure, drag, and lift coefficients) are in very good agreement with the previously published results obtained using other methods for the Oseen flow past circular and elliptic cylinders, as well as past two circular cylinders. In the inverse obstacle problem the boundary data and the internal measurement of the fluid velocity are minimized using the MATLAB© optimization toolbox lsqnonlin routine. Regularization was found necessary in the case the measured data are contaminated with noise. Numerical results show accurate and stable reconstructions of various star‐shaped obstacles of circular, bean, or peanut cross‐section
Clinical evolution of patients with post-COVID syndrome
Universitatea de Stat de Medicină şi Farmacie „Nicolae Testemiţanu”, Chişinău, Republica MoldovaIntroducere. Riscul apariției sindromului post-COVID (SPC) este determinat de severitatea infecției cu SARS-CoV2 și de statutul comorbid al pacientului. Se manifestă printr-o stare de astenie agravată de o activitate fizică minoră, tulburări de miros și gust, asociat cu tuse cronică. Scopul studiului. Evaluarea caracteristicelor generale și a particularităților clinico-evolutive ale pacienților cu sindromul post-COVID. Material și metode. S-a efectuat o cercetare prospectivă, care a inclus 69 pacienți diagnosticați cu sindromul post-COVID în perioada a 2022 în mun. Chișinău. Rezultate. particularități generale: raport bărbați/femei = 4/1, raport vârstă 45+/3 luni la 24(38%) pacienți. Clinic s-a manifestat prin astenie la toți, febră -28(44%), tuse seacă - 50 (79%), dispnee - 42 (67%), dureri toracice -28(44%), labilitate emoțională la 12(17%) și paraclinic VSH crescut-23 (36%), PCR crescută-42 (61%), LDH crescut-28 (44%) și radiologic îngroșarea desului peribronhovascular la 34 (49%). Anosmie și ageuzie nu s-a stabilit. Concluzie. Caracteristice pacienților cu SPC au fost sexul masculin, vârsta peste 45 de ani, cu reședința urbană, și condiții predispozante (comorbidități, obezitate). Particularitățile clinico-evolutive au fost astenia, tusea cu evoluție insidioasă, PCR crescut și îngroșarea desenului peribronhovascular la examenul radiologic.Introduction. The risk of post-COVID syndrome (PCS) is determined by the severity of SARS-CoV2 infection and the patient’s comorbid state. It is recognized by asthenia worsened by minor physical activity, disturbances of smell and taste, accompanied by a chronic cough. The aim of the study was to assess the general characteristics and the clinical peculiarities of patients with the post-COVID syndrome. Material and methods. A prospective research, which included 69 patients diagnosed with post-COVID syndrome in the period of 2022 in the Chisinau, was conducted. Results. General characteristics: male/female = 4/1, age ratio 45+/3 months in 24 (38%) patients. Clinically was established asthenia in all, fever - 28 (44%), dry cough -50 (79%), dyspnea – 42 (67%), chest pain - 28 (44%), emotional lability in 12 (17%) and paraclinical elevated ESR - 23 (36%), elevated CRP – 42 (61%), elevated LDH - 28 (44%) and radiologically - peribronchovascular thickening in 34 (49%) patients. Anosmia and ageusia was not established. Conclusion. Male sex, age over 45, with urban residence, and predisposing conditions (comorbidities, obesity) were patients characteristic with SPC. The clinical-evolutionary features were asthenia, cough with insidious evolution, increased CRP and thickening of the peribronchovascular pattern on radiological examination
Identification of the time-dependent conductivity of an inhomogeneous diffusive material
In this paper, we consider a couple of inverse problems of determining the time-dependent thermal/hydraulic conductivity from Cauchy data in the one-dimensional heat/diffusion equation with space-dependent heat capacity/ specific storage. The well-posedness of these inverse problems in suitable spaces of continuously differentiable functions are studied. For the numerical realisation, the problems are discretised using the finite-difference method and recast as nonlinear least-squares minimization problems with a simple positivity lower bound on the unknown thermal/ hydraulic conductivity. Numerically, this is effectively solved using the lsqnonlin routine from the MATLAB toolbox. Regularization is included wherever necessary. Numerical results are presented and discussed for several benchmark test examples showing that accurate and stable numerical solutions are achieved. The outcomes of this study will be relevant and of importance to the applied mathematics inverse problems community working on thermal/hydraulic property determination in heat transfer and porous media
Determination of time-dependent coefficients for a weakly degenerate heat equation
In this paper, we consider solving numerically for the first time inverse problems of determining the time-dependent thermal diffusivity coefficient for a weakly degenerate heat equation, which vanishes at the initial moment of time, and/or the convection coefficient along with the temperature for a one-dimensional parabolic equation, from some additional information about the process (the so-called over-determination conditions). Although uniquely solvable these inverse problems are still ill-posed since small changes in the input data can result in enormous changes in the output solution. The finite difference method with the Crank-Nicolson scheme combined with the nonlinear Tikhonov regularization are employed. The resulting minimization problem is computationally solved using the MATLAB toolbox routine lsqnonlin. For both exact and noisy input data, accurate and stable numerical results are obtained
Determination of a Time-Dependent Free Boundary in a Two-Dimensional Parabolic Problem
The retrieval of the timewise-dependent intensity of a free boundary and the temperature in a two-dimensional parabolic problem is, for the first time, numerically solved. The measurement, which is sufficient to provide a unique solution, consists of the mass/energy of the thermal system. A stability theorem is proved based on the Green function theory and Volterra’s integral equations of the second kind. The resulting nonlinear minimization is numerically solved using the lsqnonlin MATLAB optimization routine. The results illustrate the reliability, in terms of accuracy and stability, of the time-dependent free surface reconstruction
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