Carbon fibre-graphene composite polylactic acid (PLA) material for COVID shield frame
Challenges in the development of carbon fibre and graphene reinforced composite polylactic acid material is reserved in this research. A screw extrusion process is used to blend the carbon fibre particle (1 wt.%) and graphene (1 wt.%) with poly lactic acid pellets (98 wt.%) to extrude and draw a continuous composite poly lactic acid wire. The size of the wire drawn is 1.75 mm and it is found uniform in shape. Through electron microscope, the dispersion of carbon fibre and graphene in the polylactic acid material is confirmed with good bonding. Subsequently, the presence of carbon fibre and graphene reinforcement in polylactic acid material is confirmed through the x-ray diffraction peaks. The composite polylactic acid material developed through screw extrusion is to build a mechanical test sample. The strength of composite polylactic acid material is 31 MPa and 3D printed composite polylactic acid material is 63 MPa. The density of the composite material is found increased in 3D printed material than the raw polylactic acid material. With valid mechanical and thermal properties of composite polylactic acid material, a commercial product is developed. An autoclavable COVID -19 face shield is designed and developed through Fused filament fabrication 3D printer and the same was implemented.
The effects of proteoglycan surface patterning on neuronal pathfinding
Protein micropatterning techniques are increasingly applied in cell choice assays to investigate fundamental biological phenomena that contribute to the host response to implanted biomaterials, and to explore the effects of protein stability and biological activity on cell behavior for in vitro cell studies. In the area of neuronal regeneration the protein micropatterning and cell choice assays are used to improve our understanding of the mechanisms directing nervous system during development and regenerative failure in the central nervous system (CNS) wound healing environment. In these cell assays, protein micropatterns need to be characterized for protein stability, bioactivity, and spatial distribution and then correlated with observed mammalian cell behavior using appropriate model system for CNS development and repair. This review provides the background on protein micropatterning for cell choice assays and describes some novel patterns that were developed to interrogate neuronal adaptation to inhibitory signals encountered in CNS injuries.
Space flight and bone formation
Major physiological changes which occur during spaceflight include bone loss, muscle atrophy, cardiovascular and immune response alterations. When trying to determine the reason why bone loss occurs during spaceflight, one must remember that all these other changes in physiology and metabolism may also have impact on the skeletal system. For bone, however, the role of normal weight bearing is a major concern and we have found no adequate substitute for weight bearing which can prevent bone loss. During the study of this problem, we have learned a great deal about bone physiology and increased our knowledge about how normal bone is formed and maintained. Presently, we do not have adequate ground based models which can mimic the tissue loss that occurs in spaceflight but this condition closely resembles the bone loss seen with osteoporosis. Although a normal bone structure will respond to application of mechanical force and weight bearing by forming new bone, a weakened osteoporotic bone may have a tendency to fracture. The study of the skeletal system during weightless conditions will eventually produce preventative measures and form a basis for protecting the crew during long term space flight. The added benefit from these studies will be methods to treat bone loss conditions which occur here on earth.
Human Low Density Lipoprotein (LDL) and Human Serum Albumin (HSA) Co-Adsorption Onto the C18-Silica Gradient Surface
Co-adsorption kinetics of human low density lipoprotein (LDL) and serum albumin (HSA) on hydrophilic/hydrophobic gradient silica surface were studied using Total Internal Reflection Fluorescence (TIRF) and autoradiography. Two experimental systems were examined: (1) fluorescein-labeled LDL (FITC-LDL) adsorption from a FITC-LDL + HSA solution mixture onto the octadecyldi-methylsilyl (C18)-silica gradient surface, and (2) the FITC-LDL adsorption onto the HSA pre-adsorbed on the C18-silica gradient surface. Experiments with fluorescein-labeled albumin (FITC-HSA) and unlabeled LDL have been performed in parallel. The adsorption kinetics of FITC-LDL onto the hydrophilic silica was found to be transport-limited and not affected by co-adsorption of HSA. A slower adsorption kinetics of lipoprotein onto the silica with pre-adsorbed HSA layer resulted from a slow appearance of LDL binding sites exposed by the process of HSA desorption. In the region of increasing surface density of C18 groups, the FITC-LDL adsorption rate fell below the transport-limited adsorption rate, except in the very early adsorption times. Pre-adsorption of HSA onto the C18-silica gradient region resulted in a significant decrease of both the FITC-LDL adsorption rate and adsorbed amount. The lowest FITC-LDL adsorption was found in the region of C18 self-assembled monolayer, where the pre-adsorbed HSA layer almost completely eliminated lipoprotein binding.