Poly(N-isopropylacrylamide): experiment, theory and application

Temperature-sensitive aqueous microgels.

Jets, ie collimated streams of matter, occur from the microscale up to the large-scale structure of the universe Our focus will be mostly on surface tension effects, which result from the cohesive properties of liquids Paradoxically, cohesive forces promote the breakup of jets, widely encountered in nature, technology and basic science, for example in nuclear fission, DNA sampling, medical diagnostics, sprays, agricultural irrigation and jet engine technology Liquid jets thus serve as a paradigm for free-surface motion, hydrodynamic instability and singularity formation leading to drop breakup In addition to their practical usefulness, jets are an ideal probe for liquid properties, such as surface tension, viscosity or non-Newtonian rheology They also arise from the last but one topology change of liquid masses bursting into sprays Jet dynamics are sensitive to the turbulent or thermal excitation of the fluid, as well as to the surrounding gas or fluid medium The aim of this review is to provide a unified description of the fundamental and the technological aspects of these subjects

Physics of liquid jets

Polymers have played an integral role in the advancement of drug delivery technology by providing controlled release of therapeutic agents in constant doses over long periods, cyclic dosage, and tunable release of both hydrophilic and hydrophobic drugs. From early beginnings using off-the-shelf materials, the field has grown tremendously, driven in part by the innovations of chemical engineers. Modern advances in drug delivery are now predicated upon the rational design of polymers tailored for specific cargo and engineered to exert distinct biological functions. In this review, we highlight the fundamental drug delivery systems and their mathematical foundations and discuss the physiological barriers to drug delivery. We review the origins and applications of stimuli-responsive polymer systems and polymer therapeutics such as polymer-protein and polymer-drug conjugates. The latest developments in polymers capable of molecular recognition or directing intracellular delivery are surveyed to illustrate areas of research advancing the frontiers of drug delivery.

Polymers for Drug Delivery Systems

Interest in thermoresponsive polymers has steadily grown over many decades, and a great deal of work has been dedicated to developing temperature sensitive macromolecules that can be crafted into new smart materials. However, the overwhelming majority of previously reported temperature-responsive polymers are based on poly(N-isopropylacrylamide) (PNIPAM), despite the fact that a wide range of other thermoresponsive polymers have demonstrated similar promise for the preparation of adaptive materials. Herein, we aim to highlight recent results that involve thermoresponsive systems that have not yet been as fully considered. Many of these (co)polymers represent clear opportunities for advancements in emerging biomedical and materials fields due to their increased biocompatibility and tuneable response. By highlighting recent examples of newly developed thermoresponsive polymer systems, we hope to promote the development of new generations of smart materials.

New directions in thermoresponsive polymers.

Supercritical fluid extraction was applied to the separation and purification of indole. Indole is important as a feedstock for tryptophan, which is used in the field of biotechnology.Supercritical fluid extraction of coal tar oil including indole was conducted using CO2 and C2H4. Not much indole was extracted, but it was concentrated in the raffinate. To concentrate high-purity indole in the rafflnate, ethylene glycol and mono ethanol amine (MEA) were used as additives for supercritical fluid extraction by C2H4. After distiflation of the raffinate with MEA was conducted, high-purity indole was obtained. On the basis of these results, a newly developed process was proposed that uses combined supercritical fluid extraction to separate high-purity indole from coal tar oil.

Separation and Purification of Indole from Coal Tar by Supercritical Fluid Extraction

Infrared spectra of supercritical carbon dioxide were measured at various pressures and temperatures. The Fermi resonance absorbance of supercritical CO2 was influenced by pressure and temperature. The absorbance data revealed that the density dependence of Fermi resonance in the vicinity of the critical point was different from that in the region far from the critical point and was found to be related to that of the isothermal compressibility.

Density dependence of fermi resonance of supercritical carbon dioxide

Le diametre moyen des gouttes depend de la vitesse d'agitation et de la tension superficielle, et decroit lorsque la viscosite des gouttes augmentent. Mise en place d'une correlation simple

Correlation of drop sizes in liquid-liquid agitation at low dispersed phase volume fractions

Heat transfer to pseudoplastic fluids was investigated in an agitated tank with helical ribbon impeller. A previous flow model developed for Newtonian fluids was extended for heat transfer in pseudoplastic fluids by the introduction of a simple model to evaluate the effects of fluid pseudoplasticity on axial velocity gradient at the wall. The extended model was shown to be effective in correlating heat transfer coefficients and in estimating temperature distributions in an agitated tank for both Newtonian and pseudoplastic fluids.

https://www.jstage.jst.go.jp/article/jcej1968/16/6/16_6_489/_pdf

Mechanism of heat transfer to pseudoplastic fluids in an agitated tank with helical ribbon impeller

Hydraulic transport of solid materials through pipe bends was investigated experimentally. Four kinds of 90° pipe bends of which the radii of curvature were 0, 12, 24 and 48cm, were made of polyacrylate pipe. The pressure drops were measured over sections of about 5 m, each including a pipe bend. The solid particles used in this experiment were glass beads (0.5-2.0mm diameter) and polystyrene particles (1.0mm diameter). The behavior of particles in pipe bends was found to be very much complicated by the effect of gravitational and centrifugal forces and the secondary flow of fluid. The results of the pressure-drop measurement were as follows, a) The horizontal pipe Bend : In the case of polystyrene particles, even though delivered particle concentration exceeded about 20%, the effect of particle concentration mc on the pressure drop did not appear to be the same as in the case of a straight pipeline. On the other hand, in the case of glass particles the additional pressure drop, which was nearly constant regardless of flow rate, increased with increasing particle concentration except where R=0 and 12cm. Moreover, the additional pressure drop was correlated by the dimensionless term Um2/gR (ρs/ρw-1) and mc. b) The vertical pipe bend : It was found from experiment that both polystyrene and glass particles showed additional pressure drop, which was nearly constant regardless of the flow rate, similar to the case of horizontal pipe bends.

Shozaburo Saito

Papers

Separation and Purification of Indole from Coal Tar by Supercritical Fluid Extraction

Density dependence of fermi resonance of supercritical carbon dioxide

Correlation of drop sizes in liquid-liquid agitation at low dispersed phase volume fractions

Mechanism of heat transfer to pseudoplastic fluids in an agitated tank with helical ribbon impeller

Hydraulic conveying of solids through pipe bends