524 research outputs found
Lyotropic Liquid Crystalline Phases for the Formulation of Future Functional Foods
The especial features and advanced characteristics of Lyotropic Liquid Crystalline (LLC) phases as potent nano materials for encapsulation and the development of novel delivery systems for nutraceuticals and other bioactive compounds are reviewed. Exemplary, a focus is set on the health benefits of flavonoids and their current restrictions in bioavailability. Accordingly, our visions for application of LLC phases in the engineering of enhanced flavonoid-based food supplements and correlated challenges to over come are highlighted
Analysis of a Carbon Fiber Reinforced Polymer Impact Attenuator for a Formula SAE Vehicle Using Finite Element Analysis
The Hashin failure criteria and damage evolution model for laminated fiber reinforced polymers are explored. A series of tensile coupon finite element analyses are run to characterize the variables in the physical model as well as modeling techniques for using an explicit dynamic solver for a quasi-static problem. An attempt to validate the model on an axial tube crush is presented. It was found that fiber buckling was not occurring at the impactor-tube interface. Results and speculation as to why the failure initiation is incorrect are discussed. Lessons learned from the tube crush are applied successfully to the quasi-static Formula SAE nosecone crush test. The model is validated by experimental data and the impact metrics between the test and model are within 5%. Future work and possible optimization techniques are discussed
Formula SAE Hybrid Carbon Fiber Monocoque / Steel Tube Frame Chassis
The Cal Poly Formula SAE Team created this project in order to design and fabricate a high-performance chassis which would be competitive at 2013 FSAE Lincoln, and to document the process so that future teams could more easily create a chassis. One of the main goals was to reduce weight from the 143- lb 2012 chassis subsystem. A weight of 95 lb was achieved, with 82 lb in the chassis structure itself and a predicted torsional stiffness of 1700 lb*ft/deg. Composite materials design and manufacturing techniques were developed during the project. Design, testing, and manufacturing processes are detailed, and results and future work are discussed
Prototyping Visual Learning Analytics Guided by an Educational Theory Informed Goal
Prototype work can support the creation of data visualizations throughout the research and development process through paper prototypes with sketching, designed prototypes with graphic design tools, and functional prototypes to explore how the implementation will work. One challenging aspect of data visualization work is coordinating the expertise of people from a variety of roles to produce data visualizations guided by an educational theory informed goal (ETIG) in order to better support research. When collaborating, concessions must be made: typically, everyone seeks to follow the best practices established within their own disciplines. This paper attempts to illustrate how to rethink this interdisciplinary approach to adhere more strictly to educational research goals and consider how we may need to, at times, break away from best practices with the intent to evaluate the novel decisions resulting from this approach. A case study of the creation of a self-reported emotional measure is used to illustrate this type of collaboration. By taking this approach, a clear departure from best practices occurs in the scale selection for the visualization in order to support the ETIG
Fullerene up-take alters bilayer structure and elasticity: A small angle X-ray study.
The coupling of fullerene (C60) to the structure and elasticity of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine bilayers has been explored by synchrotron small angle X-ray scattering. Multilamellar vesicles were loaded with 0, 2 and 10mol.% of C60 and studied in a temperature range from 15 to 65°C. The addition of C60 caused an increase in the bilayer undulations (∼20%), in the bilayer separation (∼15%), in the linear expansion coefficient and caused a drop in the bending rigidity of the bilayers (20-40%). Possible damaging effects of fullerene on biomembranes are mainly discussed on the basis of altered bilayer fluidity and elasticity changes
New phases induced by sucrose in saturated phosphatidylethanolamines: an expanded lamellar gel phase and a cubic phase
AbstractA new lamellar gel phase (Lβ) with expanded lamellar period was found at low temperatures in dihexadecylphosphatidylethanolamine (DHPE) and dipalmitoylphosphatidylethanolamine (DPPE) dispersions in concentrated sucrose solutions (1–2.4 M). It forms via a cooperative, relatively broad transition upon cooling of the Lβ gel phase of these lipids. According to the X-ray data, the transformation between Lβ and Lβ is reversible, with a temperature hysteresis of 6–10°C and a transition width of about 10°C. No specific volume changes and a very small heat absorption of about 0.05 kcal/mol accompany this transition. The Lβ−Lβ transition temperature strongly depends on the disaccharide concentration. From a value of about 10°C below the melting transition of DHPE, it drops by 25°C with decrease of sucrose concentration from 2.4 M to 1 M. The low-temperature gel phase Lβ has a repeat spacing by 8–10 Å larger than that of the Lβ gel phase and a single symmetric 4.2 Å wide-angle peak. It has been observed in 1. 1.25, 1.5 and 2.4 M solutions of sucrose, but not in 0.5 M of sucrose. The data clearly indicate that the expanded lamellar period of the Lβ phase results from a cooperative, reversible with the temperature, increase of the interlamellar space of the Lβ gel phase. Other sugars (trehalose, maltose, fructose, glucose) induce similar expanded low-temperature gel phases in DHPE and DPPE. The Lβ phase is osmotically insensitive. Its lamellar period does not depend on the sucrose concentration, while the lattice spacings of the Lα, Lβ and HH phases decrease linearly with increase of sucrose concentration. Another notable sugar effect is the induction of a cubic phase in these lipids. It forms during the reverse HH−Lα phase transition and coexists with the Lα phase in the whole temperature range between the HH and Lβ phases. The cubic phase has only been observed at sucrose concentrations of 1 M and above. In accordance with previous data, sucrose suppresses the Lα phase in both lipids and brings about a direct Lβ−HH phase transition in DHPE. A rapid, reversible gel-subgel transformation takes place at about 17°C in both DPPE and DHPE. Its properties do not depend on the sucrose concentration. The observed new effects of disaccharides on the properties of lipid dispersions might be relevant to their action as natural protectants
Hybrid Vesicle Stability under Sterilisation and Preservation Processes Used in the Manufacture of Medicinal Formulations
Sterilisation and preservation of vesicle formulations are important considerations for their viable manufacture for industry applications, particular those intended for medicinal use. Here, we undertake an initial investigation of the stability of hybrid lipid-block copolymer vesicles to common sterilisation and preservation processes, with particular interest in how the block copolymer component might tune vesicle stability. We investigate two sizes of polybutadiene-block-poly(ethylene oxide) polymers (PBd12-PEO11 and PBd22-PEO14) mixed with the phospholipid 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) considering the encapsulation stability of a fluorescent cargo and the colloidal stability of vesicle size distributions. We find that autoclaving and lyophilisation cause complete loss of encapsulation stability under the conditions studied here. Filtering through 200 nm pores appears to be viable for sterilisation for all vesicle compositions with comparatively low release of encapsulated cargo, even for vesicle size distributions which extend beyond the 200 nm filter pore size. Freeze-thaw of vesicles also shows promise for the preservation of hybrid vesicles with high block copolymer content. We discuss the process stability of hybrid vesicles in terms of the complex mechanical interplay between bending resistance, stretching elasticity and lysis strain of these membranes and propose strategies for future work to further enhance the process stability of these vesicle formulations
- …