1,721,065 research outputs found
On the thermal stresses in chiral porous elastic beams
Full text linkThis paper is concerned with the strain gradient theory of porous thermoelastic solids. We study the deformation of isotropic chiral cylinders subjected to a temperature field that is linear in the axial coordinate. It is shown that the solution can be reduced to the study of two-dimensional problems. The results are used to investigate the deformation of a circular cylinder subjected to a uniform temperature variation. In contrast to the case of achiral materials, the thermal field in chiral cylinders produces torsional effects. © 2023, The Author(s)
Hemorheology and microcirculation in some pathologies of internal medicine
No full textIt is very interesting in physiopathology to evaluate the blood flow in the microvasculature of patients affected by diabetes, arterial hypertension, lipoproteinosis, peripheral occlusive arterial disease (POAD) and liver failure.Aim. It is very interesting in physiopathology to evaluate the blood flow in the microvasculature of patients affected by diabetes, arterial hypertension, lipoproteinosis, peripheral occlusive arterial disease (POAD) and liver failure. Methods. We studied 4 groups. Group 1: controls formed by 25 healthy subjects (15 males and 10 females aged 36±3 years); group 2: diabetes, including 32 patients (group 2A, 20 subjects with diabetes type 1: 12 males and 8 females aged 43±4 years and group 2B, 12 subjects with diabetes type 2: 6 males and 6 females aged 45±3 years); group 3: liver failure, formed by 6 subjects (3 males and 3 females aged 44±5 years); group 4: hypertensives, 50 subjects (group 4A, 28 smokers 12 males and 16 females aged 40±4 years and group 4B, 22 non-smokers: 12 males and 10 females aged 38±3 years). We evaluated the capillary morphology using computerized videocapillaroscopy, the hemorheology (red blood cell - RBC deformability and aggregability) using LORCA (Laser assisted Optical Rotational Red Cell Analyzer) and tissue oxygenation using transcutaneous oxymeter (Periflux 5000 - Perimed). Statistical analysis were performed using the Student t-test. Results. The capillary loops in patients with diabetic microangiopathy had in 50% of the patients studied an image such as "deer horns", as "elephant nose" in 72% and as "cork screw" in 44%. In diabetics we found also a capillary rarefaction in 28% of them. An improvement in perfusion was observed in patients with liver failure one week after liver transplantation from cadaver in 83% of them. Morphological alterations were present in hypertensives (27% in non-smokers, 46% in smokers). The RBC deformability evaluated as elongation index (EI) and RBC aggregability (t1/2 expressed in seconds) were detected using LORCA. Group 1: EI 0.59±0.02, t1/2 3±1 s; group 2A: EI 0.55±0.01; t1/2 2±0.5 s p<0.05 vs controls; group 2B: EI 0.56±0.01; t1/2 2±0.2 s p<0.04 vs controls; group 3: EI 0.56±0.02, t1/2 2±0.4 s p<0.04; group 4A: EI 0.56±0.02, t1/2 2±0.6 s p<0.03; group 4B: 0.57±0.02, t1/2 2±0.6 s p<0.04. We evaluated also the TcpO2 at the dorsum of the right foot expressed in mmHg: group 1, 96±11 mmHg; group 2A, 74±9 p<0.05 vs controls; group 2B, 76±8 mmHg p<0.05; group 3, 69±6 mmHg p<0.05; group 4A, 70±5 mmHg p<0.05; group 4B, 77±9 mmHg p<0.05. Conclusion. This study indicates an interesting and complete methodology in order to evaluate the microcirculation condition in different pathologies inducing microvasculature alterations
Fundamental solution in the theory of viscoelastic mixtures
No full textIn the first part of the paper, we derive a linear theory of thermoviscoelastic binary mixtures. Then, the fundamental solution of the system of linear coupled partial differential equations of steady oscillations (steady vibrations) of the theory of viscoelastic binary mixtures is constructed in terms of elementary functions, and basic properties are established
Non-simple elastic materials with double porosity structure
Full text linkThis paper is concerned with a strain gradient theory of elastic materials that have a double porosity structure. Firstly, we present the basic equations and the boundary conditions of the nonlinear theory. Then, we derive the equations of the linear theory and present the constitutive equations for chiral materials. The theory is applied to study the deformation of a chiral cylinder. The materials with a double porosity are of interest in geophysics and in mechanics of bone
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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