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Leaching Method (leaching + method)
Selected AbstractsThe CARSO procedure in process optimizationJOURNAL OF CHEMOMETRICS, Issue 1 2003Massimo Baroni Abstract This paper reports the optimization of the operative conditions of an industrial plant, the electrolytic production of zinc by the leaching method, on applying the CARSO procedure, a response surface methodology based on PLS modelling, the peculiarity of which lies in the way the highest response value within the experimental domain is found. The results illustrate the operative ranges of a few key parameters for six different responses. Copyright © 2003 John Wiley & Sons, Ltd. [source] A composite material model for improved bone formationJOURNAL OF TISSUE ENGINEERING AND REGENERATIVE MEDICINE, Issue 7 2010Silvia Scaglione Abstract The combination of synthetic polymers and calcium phosphates represent an improvement in the development of scaffolds for bone-tissue regeneration. Ideally, these composites provide both mechanically and architecturally enhanced performances; however, they often lack properties such as osteoconductivity and cell bioactivation. In this study we attempted to generate a composite bone substitute maximizing the available osteoconductive surface for cell adhesion and activity. Highly porous scaffolds were prepared through a particulate leaching method, combining poly-,-caprolactone (PCL) and hydroxyapatite (HA) particles, previously coated with a sucrose layer, to minimize their embedding by the polymer solution. Composite performances were evaluated both in vitro and in vivo. In PCL,sucrose-coated HA samples, the HA particles were almost completely exposed and physically distinct from the polymer mesh, while uncoated control samples showed ceramic granules massively covered by the polymer. In vivo results revealed a significant extent of bone deposition around all sucrose-coated HA granules, while only parts of the control uncoated HA granules were surrounded by bone matrix. These findings highlight the possibility of generating enhanced osteoconductive materials, basing the scaffold design on physiological and cellular concepts. Copyright © 2010 John Wiley & Sons, Ltd. [source] Porous Biodegradable Scaffold: Predetermined Porosity by Dissolution of Poly(ester-anhydride) Fibers from Polyester MatrixMACROMOLECULAR BIOSCIENCE, Issue 7 2009Jaana Rich Abstract A novel selective leaching method for the porogenization of the biodegradable scaffolds was developed. Continuous, predetermined pore structure was prepared by dissolving fast eroding poly(, -caprolactone)-based poly(ester-anhydride) fibers from the photo-crosslinked poly(, -caprolactone) matrix. The porogen fibers dissolved in the phosphate buffer (pH 7.4, 37,°C) within a week, resulting in the porosity that replicated exactly the single fiber dimensions and the overall arrangement of the fibers. The amount of the porosity, estimated with micro-CT, corresponded with the initial amount of the fibers. The potential to include bioactive agents in the porogen fibers was demonstrated with the bioactive glass. [source] Pulsed electromagnetic fields affect osteoblast proliferation and differentiation in bone tissue engineeringBIOELECTROMAGNETICS, Issue 7 2007Ming-Tzu Tsai Abstract Bone tissue engineering is an interdisciplinary field involving both engineers and cell biologists, whose main purpose is to repair bone anatomical defects and maintain its functions. A novel system that integrates pulsed electromagnetic fields (PEMFs) and bioreactors was applied to bone tissue engineering for regulating osteoblast proliferation and differentiation in'vitro. Osteoblasts were acquired from the calvaria of newborn Wistar rats and isolated after sequential digestion. Poly(DL -lactic-co-glycolic acid) (PLGA) scaffolds were made by the solvent merging/particulate leaching method. Osteoblasts were seeded into porous PLGA scaffolds with 85% porosity and cultured in bioreactors for the 18-day culture period. Cells were exposed to PEMF pulsed stimulation with average (rms) amplitudes of either 0.13, 0.24, or 0.32 mT amplitude. The resulting induced electric field waveform consisted of single, narrow 300 µs quasi-rectangular pulses with a repetition rate of 7.5'Hz. The results showed that PEMF stimulation for 2 and 8 h at .13 mT increased the cell number on days 6 and 12, followed by a decrease on day 18 using 8 h stimulation. However, ALP activity was decreased and then increased on days 12 and 18, respectively. On the other hand, PEMF-treated groups (irrespective of the stimulation time) at 0.32 mT inhibited cell proliferation but enhanced ALP activity during the culture period. These findings suggested that PEMF stimulation with specific parameters had an effect on regulating the osteoblast proliferation and differentiation. This novel integrated system may have potential in bone tissue engineering. Bioelectromagnetics 28:519,528, 2007. © 2007 Wiley-Liss, Inc. [source] Effects of Composition, Solvent, and Salt Particles on the Physicochemical Properties of Polyglycolide/Poly(lactide- co -glycolide) ScaffoldsBIOTECHNOLOGY PROGRESS, Issue 6 2006Yung-Chih Kuo Polyglycolide (PGA)/poly(lactide- co -glycolide) (PLGA) scaffolds were fabricated by a solvent casting/particulate leaching method using hexafluoroisopropanol (HFIP) or acetone for material dissolution and NaCl particles as porogen. The results revealed that the mechanical strength increased as the PGA percentage in a HFIP-processed scaffold increased. Chemical ingredients did not substantially affect the mechanical strength of acetone-processed scaffolds. Large NaCl particles led to weak mechanical strength, low porosity, and small specific surface area. For a fixed composition, PGA crystals in a HFIP-processed scaffold were smaller than those in an acetone-processed scaffold. High PGA fractions yielded partly fused PGA/PLGA scaffolds. A faster degradation rate of a scaffold could result from a higher PGA percentage, smaller NaCl particles, or the existence of chondrocytes. The combination of PGA and PLGA, which compensated each other for bioactivity, would be beneficial to cartilage regeneration. [source] | ||||||||||