Influence of cardiac resynchronization therapy on oxidative stress markers in patients with chronic heart failure

Background: The aim of the study was to assess changes of substances of oxidative stress in patients treated with cardiac resynchronization therapy (CRT).Methods: The study comprised 51 patients with median age of 66 years. The presence, severity, and changes of oxidative stress during CRT were assessed and expressed as malondialdehyde (MDA) concentration in plasma or in red blood cells. Antioxidant activity was assessed by the activity of catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GPx) in red blood cells. The concentration and activities were analyzed directly prior to implantation, 2–5 days after the procedure and after 6 months. Follow-up (6 months) included clinical, echocardiographic and implanted device assessments.Results: During the follow-up, 14% patients died. The median percentage of biventricular pacing was 99.29%. After 6 months 88% of patients improved NYHA, 12% remained as non-responders. Left ventricular ejection fraction increased from median 21.5% to 29% (p < 0.05). Left ventricular end-diastolic diameter decreased significantly from a median of 69.5 mm to 63 mm (p < 0.05). After a 6-month study, MDA plasma concentration and the activity levels of each antioxidant enzymes (CAT, SOD, GPx) showed a statistically significant reduction (p < 0.05). Changes concerning MDA concentrations in red blood cells remained statistically insignificant.Conclusions: Resynchronization effect oxidative stress by reducing plasma concentration of MDA, CAT, SOD and GPX

Badanie separacji fazowej mieszanin polimerowych wymuszonej powierzchnią do zastosowań w pamięciach polimerowych

Narastającym problemem w ferroelektrycznych diodach pamięci na bazie mieszaniny polimerów P(VDF-TrFE) - F8BT jest występowanie tak zwanej warstwy zwilżającej. Jest to quasi-ciągła warstwa polimeru F8BT przylegająca do powierzchni elektrody. Obecność tej warstwy jest oczywistą stratą materiału półprzewodnikowego (stanowi około 60% objętości w powstałej warstwie). Zjawisko to może mieć również wpływ na różne własności elektryczne diód pamięci.Praca ta skupia się na zwiększeniu regularności filmów polimerowych poprzez separacje fazową wymuszoną wzorcem na powierzchni. Główna techniką jest micro-contact printing molekuł warstw SAM. Dzięki temu możliwe jest otrzymanie periodycznego wzoru preferencj jednego ze składników mieszaniny do danej powierzchni.The emerging problem in P(VDF-TrFE)/F8BT based ferroelectric memory diode topic is a presence of so-called “wetting layer”. It is a quasi-continuous layer of F8BT adhered to Au electrode. The presence of the wetting layer is clear waste of semiconducting material (which is about 60% of F8BT volume in dry film). Also this phenomenon may affect some electrical properties of the device.This work focuses on patterning an active polymer blends via surface-directed phase separation. The technique used in this study is micro-contact printing by using self-assembling monolayer of molecules. It allows tuning surface interactions in order to create periodic pattern of alternating areas with preferences towards one of blend’s components

Tworzenie półprzewodnikowych warstw organicznych przy użyciu metody blade-casting

Celem pracy jest opracowanie metody przygotowania cienkich warstw, tworzących organiczne ogniwa słoneczne, poprzez użycie metody blade-coating. W szczególności, możliwość tworzenia warstw polimerowych wykazujących gradient grubości.Zaczęto od przedstawienia zasady działania, składu oraz architektury urządzeń fotowoltaicznych. Następnie opisano metody tworzenia cienkich warstw. Kolejnym krokiem jest omówienie metod wyznaczania gradientu grubości (Mikroskopia Sił Atomowych, Reflektometria światła białego).W części eksperymentalnej skupiono się głównie na tworzeniu warstw polimerowych z gradientem grubości. Zaczęto od pretestu własności doctor-blade’a, poprzez przygotowanie warstw polistyrenu, jednorodnych i z gradientem grubości, na podkładzie krzemowym. Następnie zbadano możliwość zastosowania innych rodzajów materiałów na pokrywane warstwy (PEDOT:PSS) oraz na podkłady (szkło). W celu podsumowania pracy eksperymentalnej pokryto szklane podkłady mieszaniną P3HT:PCBM.The purpose of this work is to develop a protocol of preparation of thin films forming organic solar cells by means of blade-coating method. Especially the possibility of creation of polymer films with thickness gradient was studied. First the principles, composition and architecture of OPV are presented. Subsequently experimental methods for thin films preparation are described. Then methods (Atomic Force Microscopy, White Light Reflectance Spectroscopy) of determination the thickness gradient are examined. The experimental part of this work focuses mainly on thickness gradient films. At the beginning the PS has been chosen to pretest properties of doctor knife, by preparing homogenous and thickness gradient layers on silicone substrates. Then, the application of other kinds of materials for film material (PEDOT:PSS) and substrate (glass) is studied. P3HT:PCBM mixture is coated on silicone, followed by thickness examination, to summarize the studies.In the end, summary and final conclusions are presented

Cold Drawing of AISI 321 Stainless Steel Thin-Walled Seamless Tubes on a Floating Plug

The paper presents the results of an analysis of the process of drawing AISI 321 stainless steel thin-walled seamless tubes on a floating plug. The influence of the geometry of dies and plugs, drawing velocity, and lubricants on the possibility of carrying out the pipe drawing process without a loss of strength of the lubricating film and, consequently, disturbance of the forming process and tube cracking, and also on the temperature in the drawing process, the mechanical properties of the tubes drawn, and the microhardness and roughness of the inner and outer surface of the tubes was investigated. The parameters of the drawing tools used were as follows: angle of drawing dies α = 16° and floating plugs with angles of inclination of the conical part of the plug β = 11.5°, 13°, and 14°. The drawing dies and floating plugs were made of G10 sintered carbide. Drawing speed was varied over the range 1 to 10 m/min. The study used several lubricants. Tubes with dimensions (outer diameter D0, wall thickness g0 before drawing process) D0 = 19 mm, g0 = 1.2 mm and D0 = 18 mm, g0 = 1.2 mm were drawn to produce tubes with dimensions (outer diameter Dk, wall thickness gk after drawing process) Dk = 16 mm, gk = 1.06 mm on a drawbench with the same total elongation, while the diameter and wall thickness were changed. During the process, continuous measurements were made of the drawing force and temperature in the deformation zone and on the tube surface. It was found that the drawing process causes a decrease in the roughness parameters Ra and Rz of the inner surface of the tubes. Moreover, after drawing, an increase of 30–70% was observed in the microhardness of the tube material in relation to the microhardness of the charge material. Based on the test results, it can be concluded that the work of frictional forces is the main direction of optimization of tube drawing on a floating plug process of hard-deforming materials

The Role of Al-10%Si Coating in the Manufacture and Use of Aluminized Open-Joint Steel Tubes

The paper presents the results of laboratory and industrial tests on the role of Al-10%Si coatings in the manufacture and use of welded aluminized steel tubes. The tubes were fabricated from DX53D + AS120 steel tubes coated with Al-10%Si coating. Investigations were carried out on individual processes in the manufacture of welded tubes aimed at determining the effect of the coating properties on the conditions of the forming process and vice versa. In the next step, a quality assessment has been conducted on the finished tubes. Then, selected tests simulating the operating conditions of tubes used for the elements of exhaust systems are presented. Analyses of the susceptibility of strips to plastic deformation and evaluation of the adhesion of the Al-10%Si coating to the steel base metal were carried out using bending tests. From the results, it was proved that the Al-10%Si coating determines the technical features of the workpiece material, affects the manufacturing process, and determines the quality of aluminized steel tubes. The quality of the coating surface depended on the annealing temperature and annealing time. The higher the temperature, the shorter the time needed to produce a change in the coating properties. A p-value reported from a tests is less than 0.05

Statistical Analysis and Optimisation of Data for the Design and Evaluation of the Shear Spinning Process

This work proposes a research method that is a scheme that can be universally applied in problems based on the selection of optimal parameters for metal forming processes. For this purpose, statistical data optimisation methods were used. The research was based on the analysis of the shear spinning tests performed in industrial conditions. The process of shear spinning was conducted on the components made of Inconel 625 nickel superalloy. It was necessary to select the appropriate experimental plan, which, by minimising the number of trials, allowed one to draw conclusions on the influence of process parameters on the final quality of the product and was the starting point for their optimisation. The orthogonal design 2III3−1 is the only design for three factors at two levels, providing non-trivial and statistically significant information on the main effects and interactions for the four samples. The samples were analysed for shape and dimensions using an Atos Core 200 3D scanner. Three-dimensional scanning data allowed the influence of the technological parameters of the process on quality indicators, and thus on the subsequent optimisation of the process, to be determined. The methods used proved to be effective in the design, evaluation and verification of the process