A look at the use of biopolymer-based hydrogels in cartilage tissue engineering is presented. Biopolymers offer diverse and selective coupling chemisty.
The urinary bladder has certain unique anatomical features which enable it to form an effective barrier to toxic substances diffusing from the urine into the blood. The barrier function is due to the ...epithelial surface of the urinary bladder, the urothelium, which has characteristic umbrella cells, joined by tight junctions and covered by impenetrable plaques, as well as an anti-adherent mucin layer. Diseases of the urinary bladder, such as bladder carcinomas and interstitial cystitis, cause acute damage to the bladder wall and cannot be effectively treated by systemic administration of drugs. Such conditions may benefit from intravesical drug delivery (IDD), which involves direct instillation of drug into the bladder via a catheter, to attain high local concentrations of the drug with minimal systemic effects. IDD however has its limitations, since the permeability of the urothelial layer is very low and instilled drug solutions become diluted with urine and get washed out of the bladder during voiding, necessitating repeated infusions of the drug. Permeation enhancers serve to overcome these problems to some extent by using electromotive force to enhance diffusion of the drug into the bladder wall or chemical molecules, such as chitosan, dimethylsulphoxide, to temporarily disrupt the tight packing of the urothelium. Nanotechnology can be integrated with IDD to devise drug-encapsulated nanoparticles that can greatly improve chemical interactions with the urothelium and enhance penetration of drugs into the bladder wall. Nanocarriers such as liposomes, gelatin nanoparticles, polymeric nanoparticles and magnetic particles, have been found to enhance local drug concentrations in the bladder as well as target diseased cells. Intravesical drug carriers can be further improved by using mucoadhesive biomaterials which are strongly adhered to the urothelial cell lining, thus preventing the carrier from being washed away during urine voiding. This increases the residence time of the drug at the target site and enables sustained delivery of the drug over a prolonged time span. Polymeric hydrogels, such as the temperature sensitive PEG-PLGA-PEG polymer, have been used to develop
in situ gelling systems to deliver drugs into the bladder cavity. Recent advances and future prospects of biodegradable nanocarriers and
in situ gels as drug delivery agents for intravesical drug delivery are reviewed in this paper.
The efficacy of intravesical drug delivery can potentially be improved by the use of strategies such as drug-conjugated biodegradable nanocarriers, mucoadhesive polymers and
in situ gelling systems.
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Numerical study has been performed to analyse evaporation of a single droplet composed of a binary mixture of ethanol and iso-octane. The Navier-Stokes equations are solved in conjunction with VOF ...multiphase model to track the liquid/gas interface over time. Ethanol and iso-octane form a highly non-ideal mixture and therefore the UNIFAC group contribution method was used to determine the vapour-liquid equilibrium (VIE). Source terms due to interfacial mass transfer were implemented in the continuity, momentum, energy and species equations. Commercial computational fluid dynamics solver, Ansys Fluent 13.0 was used in this study. VLE, mixture transport properties and source terms due to interfacial mass transfer were implemented using user defined functions. Parametric study to analyse the effect of free stream temperature and composition, droplet temperature and composition was performed.
In this study macroscopic spray characteristics and droplet size distribution were measured for spray emanating from a six-hole solenoid GDI fuel injector. Three test fuels namely Isooctane, ethanol ...and n-butanol were used in this study. Macroscopic spray characterization was performed using Mie scattering and Schlieren Shadowgraph technique along with high speed videography. Liquid and vapor penetration length and along with the liquid/vapor spray cone angle was determined using these techniques. Phase Doppler Particle Analyzer (PDPA) was used to determine droplet size distribution. Results showed that thermo-physical properties such as saturation temperature, latent heat of vaporization, surface tension, density and viscosity of a fuel play a very important role in the spray plume penetration. Isooctane showed the least penetration lengths for all pressure and temperature conditions that were evaluated in this study, whereas butanol showed the highest penetration length. Due to the higher values surface tension, viscosity and latent heat of evaporation, alcohol sprays consisted of droplets of larger diameter.
Typically, refractory high-entropy alloys (RHEAs), comprising a two-phase ordered B2 + BCC microstructure, exhibit extraordinarily high yield strengths, but poor ductility at room temperature, ...limiting their engineering application. The poor ductility is attributed to the continuous matrix being the ordered B2 phase in these alloys. This paper presents a novel approach to microstructural engineering of RHEAs to form an "inverted" BCC + B2 microstructure with discrete B2 precipitates dispersed within a continuous BCC matrix, resulting in improved room temperature compressive ductility, while maintaining high yield strength at both room and elevated temperature.
Spray characterization of GDI injectors is of significant importance as it influences the overall engine performance and its emissions. Spray morphology under various engine like conditions ...influences engine design. Vapor bubbles are formed inside liquid droplets when hot fuel is injected into the sub-saturation pressure conditions leading to flash boiling of GDI sprays. This dramatically alters the spray morphology and therefore needs to be understood thoroughly. A spray undergoing flash boiling experiences catastrophic breakup of the liquid jet resulting in fine atomization which in turn enhances droplet evaporation. However, spray structure is significantly altered under such conditions. In the present work, effect of hot injector body was studied to understand flash boiling behaviour of alcohol fuels and which were then compared to isooctane spray characteristics under similar conditions. Experiments were performed at five different injector temperatures: 298 K, 373 K, 423 K, 473 K and 523 K. Significant difference in spray morphology was observed when the fuel temperature was increased. Reduction in overall spray cone angle was observed with increase in temperature for all the fuels considered in this study. Vapour penetration lengths increased with increase in temperature, whereas liquid penetration initially increased and then decreased significantly due to higher evaporation rate. PDPA data showed significant reduction in SMD and AMD when the temperature was raised from 298 K to 423 K. SMD for n-butanol, isobutanol and isooctane reduced by 58.45%, 54.51% and 64.87%, respectively. Similarly, AMD reduced by 65.58%, 57.12% and 74.24%, respectively.
Recently realized higher order topological insulators have taken a surge of interest among the theoretical and experimental condensed matter community. The two-dimensional second order topological ...insulators give rise to zero-dimensional localized corner modes that reside within the band gap of the system along with edge modes that inhabit a band edge next to bulk modes. Thanks to the topological nature, information can be trapped at the corners of these systems, which will be unhampered even in the presence of disorder. Being localized at the corners, the exchange of information among the corner states is an issue. Here we show that the nonlinearity in an exciton polariton system can allow the coupling between the different corners through the edge states based on optical parametric scattering, realizing a system of multiple connectible topological modes.
Additive manufacturing of magnetic materials Chaudhary, V.; Mantri, S.A.; Ramanujan, R.V. ...
Progress in materials science,
October 2020, 2020-10-00, 20201001, Letnik:
114
Journal Article
Recenzirano
Additive manufacturing (AM) is an attractive process to manufacture net shape, complex, engineering components with minimum waste; however, it has been largely applied to structural materials. AM of ...functional materials, such as magnetic materials, has received much less attention. Magnetic materials are of high and growing interest in an extremely wide range of applications, e.g., electronic devices, rotating electrical machines, electric vehicles, wind turbines, magnetic cooling, electromagnetic shielding microphones, mobiles, laptops, etc. The processing of functional materials by AM can result in novel magnetic components with improved performance and lower processing cost, motivating the present review on AM of magnetic materials. We review commonly used AM techniques, their working principles, and applications to magnetic materials. We discuss the use of the laser engineering net shaping (LENS) process to produce soft and hard magnets. This technique can also be readily employed to process compositionally graded structures for accelerated materials development through combinatorial/high throughput investigations. Such graded structures can exhibit a wide range of functional and structural properties. The structural and magnetic properties of AM processed Fe-Si, Ni-Fe, Fe-Co, soft magnetic composites, soft magnetic oxides, magnetic shape memory alloys, magnetocaloric alloys as well as high entropy alloys are described. AM of hard magnetic materials, including Alnico, Sm-Co, Nd-Fe-B and Ce-Co alloys is elucidated. The current and future trends in this area are outlined.
Experiencing stress in our everyday life is only human. Be it altercations with peers, upcoming deadlines or unnerving life events which can't be controlled.There's good stress that motivates us, and ...there's stress that's unhealthy; it controls our thoughts and feelings, leading to insomnia, heart diseases and even mental health issues. So how do we stop sweating over small things and start living blissfully?Through mind engineering, we can!Stress Management through Mind Engineering takes the readers through the process of mind engineering to help them create a stressless mind. A mind that can bear the force of the external environment by tapping the power within. Read this book to not only win over stress but also eliminate the risk of burnouts, understand the cause of high stress, reflect on one's actions and behaviour and ultimately live a happier, healthier life.
Living cells organize their internal space into dynamic condensates through liquid-liquid phase separation of multivalent proteins in association with cellular nucleic acids. Here, we study how ...variations in nucleic acid (NA)-to-protein stoichiometry modulate the condensed phase organization and fluid dynamics in a model system of multicomponent heterotypic condensates. Employing a multiparametric approach comprised of video particle tracking microscopy and optical tweezer-induced droplet fusion, we show that the interfacial tension, but not viscosity, of protein-NA condensates is controlled by the NA/protein ratio across the two-phase regime. In parallel, we utilize fluorescence correlation spectroscopy to quantify protein and NA diffusion in the condensed phase. Fluorescence correlation spectroscopy measurements reveal that the diffusion of the component protein and NA within the condensate core is governed by the viscosity, and hence, also remains insensitive to the changes in NA-to-protein stoichiometry. Collectively, our results provide insights into the regulation of multicomponent heterotypic liquid condensates, reflecting how the bulk mixture composition affects their core versus surface organization and dynamical properties.
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