Nowadays, the Internet of Things (IOT), electronics, and neural interfaces are becoming an integral part of our life. These technologies place unprecedentedly high demands on materials in terms of their mechanical and electrical properties. There are several strategies for forming conductive layers in such composites, e.
View Article and Find Full Text PDFAim: To analyze the experience of Chazov National Medical Research Center of Cardiology in patient selection for left ventricular assist device (LVAD) implantation.
Materials And Methods: 901 patients, whose documents were sent to Chazov National Medical Research Center of Cardiology from regional medical and prophylactic institutions, were screened as selection for LVAD implantation. Firstly, all patients underwent transthoracic echocardiography performed according to the extended protocol with a comprehensive assessment of the left and right ventricle size and function.
Correction for 'Piezoelectric PVDF and its copolymers in biomedicine: innovations and applications' by Vodyashkin Andrey , , 2024, 12, 5164-5185, https://doi.org/10.1039/d4bm00904e.
View Article and Find Full Text PDFCopolymers based on vinylidene fluoride are potential materials for ferroelectric memory elements. The trend in studies showing that a decrease in the degree of crystallinity can lead to an unexpected increase in the electric breakdown field is noted. An analysis of the literature data reveals that in fluorine-containing ferroelectric polymers, when using a bipolar triangular field, the hysteresis loop has an unclosed shape, with each subsequent loop being accompanied by a decrease in the dielectric response.
View Article and Find Full Text PDFThe values of the surface potentials of two sides of films of polyvinylidene fluoride, and its copolymers with tetrafluoroethylene and hexafluoropropylene, were measured by the Kelvin probe method. The microstructures of the chains in the surfaces on these sides were evaluated by ATR IR spectroscopy. It was found that the observed surface potentials differed in the studied films.
View Article and Find Full Text PDFThis paper presents an effective compact model of current transfer for the estimation of hysteresis parameters on the volt-ampere characteristics of resonant-tunneling diodes. In the framework of the compact model, the appearance of hysteresis is explained as a manifestation of internal bistability due to interelectronic interaction in the channel of the resonant-tunneling structure. Unlike the models based on the method of equivalent circuits, the interelectronic interaction in the compact model is taken into account using the concentration parameter.
View Article and Find Full Text PDFThis paper is devoted to the study of the structure and thermomechanical properties of PVDF-based ferroelectric polymer film. Transparent electrically conductive ITO coatings are applied to both sides of such a film. In this case, such material acquires additional functional properties due to piezoelectric and pyroelectric effects, forming, in fact, a full-fledged flexible transparent device, which, for example, will emit a sound when an acoustic signal is applied, and under various external influences can generate an electrical signal.
View Article and Find Full Text PDFА clinical case of a young patient with recurrent ischemic strokes is presented. The problems of diagnostic embolic strokes are discussed. We set out the algorithm for identifying patients, in whom patent foramen ovale is the most probable cause of embolic stroke.
View Article and Find Full Text PDFComposite nanomaterials have been prepared through thermal decomposition of palladium diacetate. The composite contains palladium nanoparticles embedded in high-pressure polyethylene. The materials were studied by a number of different physico-chemical methods, such as transmission electron microscopy, X-ray diffraction, X-ray absorption spectroscopy, electron paramagnetic resonance, and EXAFS.
View Article and Find Full Text PDFComputational tools provide a unique opportunity to study and design optimal materials by enhancing our ability to comprehend the connections between their atomistic structure and functional properties. However, designing materials with tailored functionalities is complicated due to the necessity to integrate various computational-chemistry software (not necessarily compatible with one another), the heterogeneous nature of the generated data, and the need to explore vast chemical and parameter spaces. The latter is especially important to avoid bias in scattered data points-based models and derive statistical trends only accessible by systematic datasets.
View Article and Find Full Text PDFAim To evaluate 30-day results of the transcatheter correction of degenerative aortic stenosis using a novel self-expandable valve, PorticoTM.Material and methods Transcatheter aortic valve implantation (TAVI) was performed in 42 patients with an intermediate surgical risk (mean age, 74.3±6.
View Article and Find Full Text PDFEmbedded copper mesh coatings with low sheet resistance and high transparency were formed using a low-cost Cu seed mesh obtained with a magnetron sputtering on a cracked template, and subsequent operations electroplating and embedding in a photocurable resin layer. The influence of the mesh size on the optoelectric characteristics and the electromagnetic shielding efficiency in a wide frequency range is considered. In optimizing the coating properties, a shielding efficiency of 49.
View Article and Find Full Text PDFA 58-year-old female patient with severe chronic heart failure and mitral regurgitation receiving an optimal drug therapy was implanted with an Optimizer Smart device for modulation of cardiac contractility and underwent transcatheter mitral plasty using a MitraClip system. The complex therapy resulted in a significant clinical improvement and beneficial dynamics of echocardiographic parameters.
View Article and Find Full Text PDFThe study was devoted to the creation of transparent electrodes based on highly conductive mesh structures. The analysis and reasonable choice of technological approaches to the production of such materials with a high Q factor (the ratio of transparency and electrical conductivity) were carried out. The developed manufacturing technology consists of the formation of grooves in a transparent substrate by photolithography methods, followed by reactive ion plasma etching and their metallization by chemical deposition using the silver mirror reaction.
View Article and Find Full Text PDFThis article presents a clinical case of successful transcatheter aortic valve implantation in an elderly patient with critical aortic stenosis at the stage of systolic dysfunction with development of genuine cardiogenic shock. The role of transcatheter aortic valve implantation in the pathogenetic treatment of acute heart failure due to decompensated aortic stenosis was briefly discussed.
View Article and Find Full Text PDFAim: To evaluate the effect of angiotensin-neprilysin receptor inhibitors on myocardial remodeling in patients with chronic heart failure and atrial fibrillation.
Materials And Methods: We studied dynamics of the parameters of ultrasound structural and functional parameters of the left atrium and left ventricle of the heart was during 3-month therapy with sacubitryl-valsartan in a group of 15 patients with a combination of chronic heart failure due to dilated and paroxysmal paroxysmal forms of atrial fibrillation.
Results: Showed a statistically significant positive effect of the use of angiotensin receptors and neprilysin inhibitors on the parameters of remodeling of the left atrium (according to transthoracic and transesophageal echocardiography), left ventricle, as well as levels of natriuretic peptides ANP and NT-pro-BNP.
Aim: To evaluate the diagnostic utility of long-term remote monitoring of ECG compared with 24 hour Holter monitoring for the detection of cardiac arrhythmias and conduction disturbance in patients with atrial fibrillation (AF) after catheter radiofrequency ablation (RFA; isolation) of the pulmonary veins.
Materials And Methods: The study included 62 patients aged 58.5±11.
We report on the results of a molecular dynamics simulation study of porous glassy media, formed in the process of isochoric rapid quenching from a high-temperature liquid state. The transition to a porous solid occurs due to the concurrent processes of phase separation and material solidification. The study is focused on topographies of the model porous structures and their dependence on temperature and average density.
View Article and Find Full Text PDFMolecular dynamics simulations are carried out to investigate mechanical properties and porous structure of binary glasses subjected to steady shear. The model vitreous systems were prepared via thermal quench at constant volume to a temperature well below the glass transition. The quiescent samples are characterized by a relatively narrow pore size distribution whose mean size is larger at lower glass densities.
View Article and Find Full Text PDFWe conducted a comprehensive atomistic simulation study of the adhesive properties of aromatic rigid-rod poly-[(4,4'diphenylene) pyromellitimide] on a dimer-reconstructed silicon surface. We describe the structural developments within the adherent's interfacial region at the atomistic scale, and evaluate the energetics of the adhesive interactions between bimaterial constituents. In particular, we observe a transition between noncontact and contact adhesion regimes as a function of the interfacial bonding strength between the polyimide repeat units and the silicon substrate.
View Article and Find Full Text PDFJ Nanosci Nanotechnol
July 2008
Representative results of computer simulation and/or modeling studies of the nanomechanical and thermal transport properties of an individual carbon nanotube, silicon nanowire, and silicon carbide nanowire systems have been reviewed and compared with available experimental observations. The investigated nanomechanical properties include different elastic moduli of carbon nanotubes, silicon nanowires, and silicon carbide nanowires, all obtained within their elastic limits. Moreover, atomistic mechanisms of elastic to plastic transition under external stresses and yielding of carbon nanotubes under experimentally feasible temperature and strain rate conditions are discussed in detail.
View Article and Find Full Text PDFWe investigate the behavior of the island vertical pairing probability in multilayer systems of Ge island quantum dots (QDs) in Si(001). By combining a simple kinetic rate model with our previously reported atomistic simulation results on the nature of the stress field from buried shallow Ge islands having {105}-oriented sidewalls, we derive an analytical expression for correlation probability as a function of the parameters characterizing the multi-QD systems. The approach is based upon continuum mechanochemical potential model, which allows one to introduce necessary elements of the kinetics of island formation in a simple way.
View Article and Find Full Text PDFPhys Rev E Stat Nonlin Soft Matter Phys
February 2005
Conventional wisdom indicates that the presence of an alternating driving force will not change the long-term behavior of a Brownian particle moving in a random potential. Although this is true in one dimension, here we offer direct evidence that the inevitable local symmetry breaking present in a two-dimensional random potential leads to the emergence of a local ratchet effect that generates large-scale vorticity patterns consisting of steady-state net diffusive currents. For small fields the spatial correlation function of the current follows a logarithmic distance dependence, while for large external fields both the vorticity and the correlations gradually disappear.
View Article and Find Full Text PDFStress distribution in laterally ordered arrays of coherent Ge islands on Si(001) buried in Si cap layers is examined using atomistic simulations. The obtained hydrostatic stress dependence on the spacer layer thickness shows a nearly linear inverse dependence, unlike the commonly used inverse cubic dependence derived in the framework of an isolated embedded force dipole source model. Additionally, the hydrostatic stress on the spacer surface is found to scale more closely with the area of the island rather than its volume as implicit in the use of the force dipole model.
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