Samples of skin, tendons, muscles, and knitwear composed of NiTi wire are studied by uniaxial cyclic tension and stretching to rupture. The metal knitted mesh behaves similar to a superelastic ...material when stretched, similar to soft biological tissues. The superelasticity effect was found in NiTi wire, but not in the mesh composed of it. A softening effect similar to biological tissues is observed during the cyclic stretching of the mesh. The mechanical behavior of the NiTi mesh is similar to the biomechanical behavior of biological tissues. The discovered superelastic effects allow developing criteria for the selection and evaluation of mesh materials composed of titanium nickelide for soft tissue reconstructive surgery.
The aim of this work is to produce calcium pectin-silica gel beads containing mesalazine as a drug model in order to control the drug release in the colon. The mesalazine loaded calcium pectin-silica ...gel beads were prepared using the ionotropic gelation method. Energy-dispersive X-ray analysis revealed that increasing the Na2SiO3 concentration led to an increase of the silicon content on the surface and in the cross-sections of the beads. The addition of Na2SiO3 to the gel formulations made from the duckweed callus culture pectin led to a decrease in the swelling degree that appeared to be related to the higher gel strength of these beads. The beads made from pectins of campion and duckweed callus cultures with adding of 22.2 mg/ml of Na2SiO3 showed the lowest release of mesalazine in simulated gastric and intestinal fluids. An increase in the reaction time up to 60 min during incubation in the cross-linking solution of CaCl2 led to a slower release of drug from the beads. An elevated release of mesalazine was achieved in the simulated colonic fluid. Prepared calcium pectin-silica gel beads containing mesalazine as a drug model can be proposed for controlled drug release in the colon.
•The mesalazine loaded pectin-silicate gel beads were prepared using the ionotropic gelation method.•The pectin-silicate gel beads made from the duckweed callus culture pectin had the higher gel strength.•The pectin-silicate gel beads with the higher content of silicon showed the lowest release of mesalazine.•An elevated drug release from pectin-silicate gel beads was achieved in the simulated colonic media.
The problem of developing conducting molecular wires has recently received increased attention. We present the results of molecular dynamics simulations aimed at investigating the self-organization ...process of conjugated 2,5-dialkoxy-phenylene-thiophene-based oligomers (TBT) on a monolayer graphene over a wide range of temperatures. The local structural characteristics of the TBT oligomers and the macroscopic characteristics of their aggregates are investigated. It is shown that electrostatic interactions significantly affect the local structural characteristics of the molecules resulting in liquid-crystalline type of ordering of the oligomers on graphene. It is also found that the length of the oligomers assures the structural stability of ordered aggregates even at elevated temperatures.
Gel microparticles were prepared from pectins of campion (SVCgel) and duckweed (LMCgel) callus cultures, as well as from commercial apple pectin (APgel) by emulsion dehydration techniques with ...successive ionotropic gelation. The morphology and swelling behavior of the microparticles were determined after successive incubation in simulated gastric (SGF), intestinal (SIF), and colonic (SCF) fluids. Both SVCgel and LMCgel microparticles were found to swell in SGF and SIF gradually, and at oral administration decreased food intake by laboratory mice during the first 5 h of free-feeding. The SVCgel microparticles demonstrated the higher stability in SCF within 24 h than LMCgel ones. Only the SVCgel microparticles were shown to decrease food intake by 24% during the 21 h of free-feeding and decreased body weight of mice by 4% during 24 h after oral administration. The APgel microparticles lost their shape in SIF, then fully disintegrated after 0.5 h of incubation in SCF, and failed to affect food intake or mice body weight. The data obtained indicated that sustainability and swelling of the gel microparticles from the SVC pectin in the colonic fluid may provide the stronger satiating effect compared to that of the LMCgel microparticles.
•Gel microparticles were prepared by emulsion dehydration techniques with successive ionotropic gelation.•Swelling capacity of the pectin gel microparticles depends on a source of pectin.•Gel microparticles extensively swelling in the acidic gastric condition were found to decrease food intake in mice.•The swelling sustainability of gel microparticles in the colonic fluid is suggested to provide satiating effect.
Mesenchymal stem cells (MSCs) are pluripotent cells that can differentiate into endothelial, osteogenic, adipogenic, and other lineages. In spite of the broad interest, little is known about the ...variation of MSC number in relation to the age of the donor. The aim of this study was to investigate the age-associated variations of bone marrow (BM) MSCs using a rat model. Cell populations were characterized by flow cytometry using light-scattering parameters, DNA content and a set of monoclonal antibodies and detected by magnetic resonance imaging (MRI). Single-cell analysis was performed by conventional fluorescent microscopy. BM mononucleated cells (MNCs) were isolated, in vitro culture of MSCs was established, and endothelial cells differentiation and intracellular magnetic labeling was shown. The amount of BM tissue obtainable from femurs and tibiae increased with age and reached a maximum in 8- to 12-week-old rats. At the same time, the proportional number of MNCs containing MSCs decreased. As a result, after 2 weeks of culture, the maximum yield of MSC number was registered from the youngest age group (4 weeks). MSCs were differentiated into endothelial cells by administration of vascular endothelial growth factor (VEGF) and subsequently revealed immunocytochemical and morphological characteristics of endothelial cells. The results of our study are the basis for further experiments with MSCs and their endothelial descendants, which may be labeled with different agents for cell tracking and detection experiments, but age-related changes in MSCs number should be taken into account whenever these cells are considered for practical applications.
•We develop calcium pectinate gel beads using modified pectins from the cell walls of campion callus.•Callus cells cultured with various medium nutrients (carbon, calcium and auxin).•Strategy ...involving changing the composition of media components alters the swelling of CaPG beads.•An applied strategy enhanced the acid and water resistance of the pectinate hydrogels.•The slow swelling of dried CaPG beads was related to their grooved surfaces.
The aim of this research is to investigate the swelling properties and morphology of the calcium pectinate gel (CaPG) beads made from pectins of campion callus cultured using various medium nutrients (carbon sources, concentration of sucrose, calcium and 2,4-dichlorophenoxyacetic acid (2,4-D)). Gelled spheres were prepared by ionotropic gelation. The mean diameter, total surface area and volume of the dried beads varied depending on the plant cell culture conditions. The swelling of dried CaPG beads in solutions with pH 2 and pH 4 was demonstrated to occur more slowly (within 4 or 24h) with increasing sucrose and calcium concentrations or in the absence of auxin. All beads swelled less when placed in acidic media (pH 2 and pH 4) and swelled most extensively in NaCl (pH 6). The surface morphology of the CaPG beads was demonstrated to depend on the presence of sugars, calcium and auxin in the plant cell culture medium used. The slow swelling of dried CaPG beads was apparently related to their grooved surfaces. An applied strategy involving changing the composition and concentration of media components altered the swelling behavior of the CaPG beads and enhanced the acid and water resistance of the resultant pectinate hydrogels in physiological environments. In particular, the swelling of Ca 4.5, 2,4-D0, Suc30 and Suc100 CaPG beads occurred more slowly.
Porous NiTi alloys were obtained by self-propagating high-temperature synthesis (SHS) using layer-by-layer combustion in closed and open gas flow reactors under a protective argon atmosphere. The ...maximum compressive strain of porous NiTi alloys synthesized in the closed reactor was 34% compared to 7% in the open gas flow reactor. X-ray diffraction, differential scanning calorimetry, scanning electron microscopy, energy dispersive spectroscopy, and optical microscopy showed that the reaction products in the two-phase gas zone of peritectic crystallization are in the form of isolated Ti
2
Ni crystalline clusters in the TiNi matrix. The ductility and strength of the recrystallized Ti
2
Ni phase hard dendrites increase the effective stiffness of porous NiTi alloys and decrease the maximum compressive strain. A highly porous NiTi alloy with improved mechanical properties was obtained by the SHS method in a closed reactor.
A pectic polysaccharide, lemnan LMC, was extracted from the callus of duckweed Lemna minor L. and was tested for adjuvant properties at oral administration with protein antigen. Mice were orally ...immunized thrice with weekly interval with free hen's egg lysozyme or lysozyme with LMC. Lemnan LMC was shown to increase delayed type hypersensitivity and serum antilysozyme IgG responses. LMC was established to increase levels of both serum IgG1 and IgG2a subclasses. The concentration of malondialdehyde and myeloperoxidase activity were found to be higher in the tissue samples obtained from small intestine of mice immunized with mixture of lysozyme/LMC than those immunized with lysozyme only.
Thus, lemnan appeared to be useful as the adjuvant for oral immunization.
Non-reflective interdigital transducers (IDTs) for surface acoustic waves (SAWs) are important elements for development of SAW devices with precise frequency responses. Until now a common way to have ...a non-reflective periodic cell of IDT at the resonance frequency is to use split electrodes with periodicity P/4 and finger width P/8, where P is the IDT period equal to the SAW wavelength. But for 2.45 GHz (ISM frequency band), standard lithography allows electrode (and gap) widths only to be about quarter-wavelength. Thus, a new structure solution for non-reflective IDT is required for high frequencies. A novel solution for non-reflective cell with two quarter-wavelength electrodes per one-wavelength period is based on 2D-periodic structure consisting of alternating active IDT tracks and passive reflector tracks. If tracks have equal apertures and if electrodes in adjacent tracks are shifted to each other by P/4, SAWs reflected from electrodes in adjacent tracks have equal amplitudes but with phases shifted by a half wavelength. So the reflected waves cancel each other and the total reflection from the structure should be equal to zero.
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