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The research work presents a new design of compression hosiery where compression around a human limb is generated using special air bladders. The pressure inside the air bladders is adjustable. The objective of the research was to study graduated compression and its control on the limb using the prototype with air bladders and two commercial compression products. The compression forces were measured around the limb under a knee in three sectors: a foot, a middle part and an upper part of the leg. Measurements were mainly done in vivo using the limb of a test person – although some pre-trials were done in vitro. During the tests it was concluded that the exact control of the compression was very difficult to achieve due to, for example, the shape and the composition of the limb. Based on the results, the compression values were unstable under the sectors and the graduated compression was nonlinear in the vertical direction for every tested hosiery. There is some analogy concerning the pressure distribution reported about standard mechanical compression hosiery. The results prove that our prototype enables one to achieve very high compression values in seconds, and to manage and to adjust instantly the compression rate in each sector. Efficient controllability and comfort are important matters in the medical treatment, where a patient wears the hosieries for prolonged times.

Objectives The aim of this study was to demonstrate the feasibility of combining the novel heart valve replacement technologies of: 1) tissue engineering; and 2) minimally-invasive implantation based on autologous cells and composite self-expandable biodegradable biomaterials. Background Minimally-invasive valve replacement procedures are rapidly evolving as alternative treatment option for patients with valvular heart disease. However, currently used valve substitutes are bioprosthetic and as such have limited durability. To overcome this limitation, tissue engineering technologies provide living autologous valve replacements with regeneration and growth potential. Methods Trileaflet heart valves fabricated from biodegradable synthetic scaffolds, integrated in self-expanding stents and seeded with autologous vascular or stem cells (bone marrow and peripheral blood), were generated in vitro using dynamic bioreactors. Subsequently, the tissue engineered heart valves (TEHV) were minimally-invasively implanted as pulmonary valve replacements in sheep. In vivo functionality was assessed by echocardiography and angiography up to 8 weeks. The tissue composition of explanted TEHV and corresponding control valves was analyzed. Results The transapical implantations were successful in all animals. The TEHV demonstrated in vivo functionality with mobile but thickened leaflets. Histology revealed layered neotissues with endothelialized surfaces. Quantitative extracellular matrix analysis at 8 weeks showed higher values for deoxyribonucleic acid, collagen, and glycosaminoglycans compared to native valves. Mechanical profiles demonstrated sufficient tissue strength, but less pliability independent of the cell source. Conclusions This study demonstrates the principal feasibility of merging tissue engineering and minimally-invasive valve replacement technologies. Using adult stem cells is successful, enabling minimally-invasive cell harvest. Thus, this new technology may enable a valid alternative to current bioprosthetic devices.

Polylactide stereocopolymer multifilament fibers were prepared by wet spinning and subsequent hot drawing. The stereocopolymers were poly-(L,D-lactide) [P(L,D)LA], L/D ratio 96/4, and poly-(L,DL-lactide) [P(L,DL)LA], L/DL ratio 70/30. They were dissolved in dichloromethane and coagulated in a spin bath containing ethanol. The hot-drawing temperature was 65°C. The draw ratios (DR) were upto 4.5 to the P(L,D)LA 96/4 filaments and upto 3 to the P(L,DL)LA 70/30 filaments. Wet spinning decreased crystallinities of both copolymers. Hot drawing increased the crystallinity of the P(L,D)LA 96/4 filament but not to the level of the original copolymer, whereas the as-spun and the hot-drawn P(L,DL)LA 70/30 filaments were amorphous. The filament diameter, tenacity, Young's modulus, and elongation at break were dependent on the DR. The maximum tenacity (285 MPa) and Young's modulus (2.0 GPa) were achieved with the P(L,D)LA 96/4 filament at the DR of 4.5. Respectively, the maximum tenacity of the hot-drawn P(L,DL)LA 70/30 filament was 175 MPa and Young's modulus 1.3 GPa at the DR of 3. Hot drawing slowed down in vitro degradation rate of both stereocopolymer filaments. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Poly(L,D-lactide) [P(L,D)LA], LL/D ratio 96/4, and poly(L,DL-lactide) [P(L,DL)LA], L/DL ratio 70/30, multifilament fibers were prepared by wet-spinning and the effects of the spin draw ratio and the coagulant on the morphological, thermal, and mechanical properties of the filaments were studied. The hydrolytic degradation of filaments was studied in vitro. The filament diameter and the mechanical properties of filaments were highly dependent on the spin draw ratio, whereas the coagulant had no or minor effect. The filament diameters were in the range of 11–36 μm and the maximum tenacity of 150 MPa was obtained at the spin draw ratio of 7.0 for both copolymers. The copolymer had the main importance on the crystallinity of filaments, but it was also affected by the duration of the coagulation process. The crystallinities of P(L,D)LA 96/4 filaments were in the range of 5–16%, whereas P(L,DL)LA 70/30 filaments were totally amorphous. The degree of crystallinity had effect on the hydrolytic degradation of filaments. The tenacity loss of P(L,D)LA 96/4 filaments was about 10% and that of P(L,DL)LA 70/30 filaments was as high as 50% after 24 weeks in vitro. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

In this study, the solubility and precipitation properties of medical-grade stereocopolymers were investigated. The solubility of the polymers was tested with eight different organic solvents and four nonsolvents. The solubility of poly(L,D-lactide) stereocopolymers was highly dependent on the L/D ratio of the copolymer. The phase-separation ability was tested by cloud-point titration with a solvent and a nonsolvent. The solvent was in all cases dichloromethane, and the nonsolvents were n-hexane, methanol, ethanol, and isopropyl alcohol. The results showed that n-hexane was the most efficient nonsolvent. Methanol and ethanol showed quite similar precipitation properties. Isopropyl alcohol was the least efficient nonsolvent of those studied. Also, the L/D ratio of the copolymer had an effect on the precipitation properties. The precipitation happened most easily when the L content was high. The molecular weight of the copolymer had only a slight effect on the phase separation. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

There is a global demand for constant increase in the production of textile fibres. Currently, the market for cellulosic fibres is dominated by cotton and viscose fibres. However, new alternative cellulosic fibres are being sought to meet the growing demand. The dyeing properties of novel fibres aiming at the marketplace are among the properties that determine their applicability to textiles. Recently, a novel process for producing cellulosic fibres, the Biocelsol process, has been scaled up so that the spinning of yarn from Biocelsol fibres is now possible. In this study, the reactive dye Levafix CA Blue was applied to cellulosic fabrics made from viscose, cotton, and Biocelsol yarns. The crystalline structure and morphology of the fibres were studied by Fourier transform infrared spectroscopy and field-emission scanning electron microscopy. The crystalline structure and morphology of the Biocelsol fibres resembled those of viscose fibres, but, owing to higher water absorption, the Biocelsol fabric had a higher dye exhaustion. The colour yield of the Biocelsol fabric was 62% and 41% higher than that of cotton and viscose fabrics respectively, suggesting that less dye is needed to gain a shade in Biocelsol fabric than in viscose and cotton fabrics.

A new strain of Agrobacterium tumefaciens (BST05) was found to grow on polyacrylonitrile (PAN; 13C labelled) converting the polymer to polyacrylic acid as shown by solid state NMR. When cultivated in a medium containing acetonitrile the bacterium produced nitrile hydratase and amidase activity. Activity recovery after lyophilisation and enzyme stability was significantly enhanced in the presence of 5% sorbitol leading to half life times of 12, 72 and 154 days at 25°C, 4°C and –20°C. The enzymes were able to convert 1.1% of the nitrile groups of PAN-powder to the corresponding acids. PAN fabrics were mainly converted to the amides as shown by an 80% increase of the O/C ratio in ESCA analysis. These data were confirmed by cationic dyeing and FTIR-ATR analysis.

During shipping and storage operations, a filter medium may be subjected to UV light, cold, humidity, and even direct wetting. Hence, it is of utmost importance that the medium and semi-finished fabric is tested against all foreseeable stresses it may encounter before it reaches its final destination. In this work, polyaniline-treated polyester filter fabrics are subjected to an intensive water shower, humidity, cold, and ultraviolet light on a labora tory scale. Weathered fabrics are measured before and after weathering for electrical resistivity in both the lateral and pass-through directions. The results indicate that polyaniline-treated woven polyester fabrics have good tolerance for all tested conditions, and electrical resistance is not significantly affected by weathering.

In this work the possibility and potential of treating cotton fibers and yarns instead of fabrics with monocomponent cellulases was investigated. Different pretreatments on fibers were performed and tested in order to improve the accessibility of cotton to enzymatic modification. The enzymatic treatments were evaluated microscopically and by analysing the effects of treated fibers on spinnability, yarn evenness, tenacity and pilling. The accessibility of the cotton fibers for cellulases could be increased by different pretreatments. Steaming of fibers prior to enzymatic treatment was found to be an efficient way to increase hydrolysis levels. Cellulase treatments of carded yarns resulted in modification of yarn properties. Decrease in yarn hairiness was observed and the knitted fabric made of the treated yarn showed a lowered tendency towards pilling. In all cases endoglucanase activity rather than cellobiohydrolase activity was responsible for these modifications.

Protein-loaded multifilament fibers were fabricated by the wet-spinning method. The polymers which were tested included poly(L,D-lactide) [P(L,D)LA], L/D ratio 96/4 and poly(L,DL-lactide) [P(L,DL)LA], L/DL ratio 70/30. The polymers were dissolved in dichloromethane and bovine serum albumin (BSA) was dissolved in water, respectively. The solutions were mixed together using a probe sonicator to form a polymer-protein emulsion. This emulsion was extruded to an ethanol spin bath. The fibers possessed a distinct sheath-core structure, where the inner core was porous and the outer sheath was smooth. The diameters of the filaments were in the range of 46 and 70 μm. The tenacity values of the filaments were between 7 and 17 MPa. In vitro drug release rate of the P(L,DL)LA 70/30 filament was faster than that of the P(L,D)LA 96/4 filament. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

The aim of this study was to demonstrate the feasibility of combining the novel heart valve replacement technologies of: 1) tissue engineering; and 2) minimally-invasive implantation based on autologous cells and composite self-expandable biodegradable biomaterials.Minimally-invasive valve replacement procedures are rapidly evolving as alternative treatment option for patients with valvular heart disease. However, currently used valve substitutes are bioprosthetic and as such have limited durability. To overcome this limitation, tissue engineering technologies provide living autologous valve replacements with regeneration and growth potential.Trileaflet heart valves fabricated from biodegradable synthetic scaffolds, integrated in self-expanding stents and seeded with autologous vascular or stem cells (bone marrow and peripheral blood), were generated in vitro using dynamic bioreactors. Subsequently, the tissue engineered heart valves (TEHV) were minimally-invasively implanted as pulmonary valve replacements in sheep. In vivo functionality was assessed by echocardiography and angiography up to 8 weeks. The tissue composition of explanted TEHV and corresponding control valves was analyzed.The transapical implantations were successful in all animals. The TEHV demonstrated in vivo functionality with mobile but thickened leaflets. Histology revealed layered neotissues with endothelialized surfaces. Quantitative extracellular matrix analysis at 8 weeks showed higher values for deoxyribonucleic acid, collagen, and glycosaminoglycans compared to native valves. Mechanical profiles demonstrated sufficient tissue strength, but less pliability independent of the cell source.This study demonstrates the principal feasibility of merging tissue engineering and minimally-invasive valve replacement technologies. Using adult stem cells is successful, enabling minimally-invasive cell harvest. Thus, this new technology may enable a valid alternative to current bioprosthetic devices.

Background : A clinically relevant heart valve tissue engineering concept requires minimally invasive techniques for both cell harvest and valve implantation. Here, we present first experiences with autologous tissue engineered heart valves fabricated from composite self-expandable biodegradable scaffolds and adult stem cells implanted by minimally invasive procedures in a sheep model. Methods : Sandwich-structured heart valve scaffolds (n= 12) were fabricated from non-woven PLDLA meshes coated with electrospun PLDLA nanofibers and integrated in self-expanding nitinol stents. Scaffolds were seeded with either autologous ovine bone marrow (BMC; n= 4) or jugular vein-derived cells (JVC; n= 8) and cultured in bioreactors. After 9d, heart valves were endothelialized with autologous peripheral blood-derived endothelial progenitor cells and jugular vein-derived endothelial cells, respectively. After additional 3d, heart valves (n= 6) were implanted trans-apically in pulmonary position. Controls were analysed (n= 6) as to tissue formation and composition (histology, biochemical assays). Mechanical properties were determined by tensile tests. In vivo performance was assessed by echocardiography up to 4 weeks. Results : Histology revealed cell attachment and ingrowth into the scaffold material resulting in layered tissues with endothelialized, eNOS positive surfaces. Amounts of GAG and cell number were similar in all heart valves, comparable to native tissues. Collagen production was higher in BMC based heart valves compared to JVC-derived tissues (Hydroyproline amount 34% vs. 20% of native tissues). Mechanical profiles demonstrated physiological tissue strength (max. tensile stress 0.41± 0.21 MPa) but less elasticity (E-Moduli 1.89± 0.79 MPa) independent of the cell source. Echocardiography displayed in vivo functionality (transvalvular mean pressure gradient 10.36± 3.17 mm/Hg) with more flexibility of BMC based heart valves leaflets. Conclusions : These results demonstrate that heart valve tissue engineering based on a minimally invasive technique for both cell harvest and valve implantation is feasible. This clinically relevant approach is currently investigated in long-term animal studies.

Conducting polyester PET and polyamide PA-6 fibre and fabrics were prepared by in-situ chemical oxidative polymerisation using super critical fluid assisted process. The fibre materials and cloths produced were characterized by means of FTIR, WAXD, SEM, and DSC and two-probe resistivity. The samples were studied also by means of washing them several times. Homogeneous treated fibre materials with sustainable properties were produced. Melt spun fibre material of inherently conducting polymer blends have been reported earlier. Reasonable mechanical and electrical properties (resistance of 105…107 Ω/cm) are typical for blend of polypropylene and polyaniline. With bi-component extrusion technology the fibre as good as 103…105 Ω/cm is reachable.