A method for displaying two images on a screen in distance medical education

This article describes a method for simultaneously displaying several images on a screen during an online multimedia presentation. Users with 'REALPLAYER' software and Web browsers can view images with synchronous audio on their personal computers via the Internet. Medical researchers and physicians often find it useful to compare images after treatment with those before treatment, by displaying several arranged images simultaneously. Medical care providers can browse this type of multimedia content in their offices and universities at their convenience. There presently exist two methods for creating multimedia content with voice and images using RealSystem technology. Electronic lectures of otorhinolaryngology explaining new surgical procedures for patients with chronic otitis media were created with this method and made available to otorhinolaryngologists through the Internet.     

Extraction of thiamylal in serum using hydrophilic acetonitrile with subzero-temperature and salting-out methods

For high-performance liquid chromatography (HPLC) of thiamylal, one of the barbiturates, the drug in serum samples was extracted by two alternative liquid-liquid extraction techniques using hydrophilic acetonitrile as a solvent and subzero-temperature and salting-out methods. Acetonitrile was mixed with the sample, separated by cooling at -20 degrees C or addition of sodium chloride, and injected directly into the HPLC apparatus. In both the methods, thiamylal was extracted effectively in the acetonitrile phase and pH adjustment of the sample was not required. The salting-out extraction method is rapid and would be suitable for quantitation of drugs in many samples. To avoid coextraction of added salt, the subzero-temperature extraction method was applied to identification of thiamylal by gas chromatography/mass spectrometry and liquid chromatography-tandem mass spectrometry.     

Magnetroviscoelastic behavior of composite gels

Dynamic viscoelasticity of silicone gels having many lines of dispersed iron particles under the influence of external magnetic fields was studied. The particulate composite enhanced its elastic modulus by action of magnetic fields. The magnetroviscoelastic behavior was caused by the cohesive forces between magnetically polarized particles and was analyzed using a simple model of induced dipole-induced dipole interactions. The presented results provide insight into the relationship between macroscopic viscoelastic behavior of the composite gels and the microscopic bondings between dispersed particles. © 1995 John Wiley & Sons, Inc.     

Subzero-temperature liquid-liquid extraction of benzodiazepines for high-performance liquid chromatography.

On the basis of the phenomenon that hydrophilic acetonitrile is separated from the aqueous phase at -20 degrees C, we employed a novel extraction method, "subzero-temperature liquid-liquid extraction", to extract benzodiazepines (estazolam and triazolam) from serum or aqueous solution for liquid chromatography. A 1:1 mixture of acetonitrile and the specimen was cooled at -20 degrees C for 20 min to separate the acetonitrile and aqueous phases. The acetonitrile phase was directly injected into a high-performance liquid chromatograph. Recovery rates of the drugs following the first subzero-temperature liquid-liquid extraction were 50.3 +/- 0.6-54.0 +/- 0.9%, which were lower than those (73.9 +/- 3.3-80.6 +/- 0.6% and 81.6 +/- 4.7-96.1 +/- 2.6%) of the first conventional liquid-liquid extraction using diethyl ether and solid-phase extraction using a Sep-Pak C18 column, respectively. However, three to four repeated subzero-temperature liquid-liquid extractions and conventional liquid-liquid extractions resulted in recovery of almost 100% of the drugs. In the chromatogram of the benzodiazepines recovered from serum by the subzero-temperature extraction, no coextracted component interfered with determination of the drugs. Detection limits of the drugs were 0.02-0.08 microgram/mL, and coefficients of variance were 1.14-2.17% suggesting high reproducibility.     

Architectural effect of poly(acrylic acid) and poly(amide imide) block copolymers on dispersion of carbon nanotubes in water

The dispersion of carbon nanotubes (CNTs) in water by poly(acrylic acid) (PAA) and poly(amide imide) (PAI) block copolymers and homo‐PAA is investigated. Poly(acrylic acid)‐block‐poly(amide imide) (PAA‐block‐PAI), poly(acrylic acid)‐block‐poly(amide imide)‐block‐poly(acrylic acid) (PAA‐block‐PAI‐block‐PAA), and heteroarm star block copolymer poly(acrylic acid)₂poly(amide imide) (PAA₂PAI) with similar molecular weights and PAA contents are used as the copolymers. The dispersion of CNTs is observed by dynamic light scattering and ultraviolet‐visible spectroscopy. The presence of the hydrophobic sequence improves the dispersion. PAA₂PAI has the best dispersion ability, followed in order by PAA‐block‐PAI‐block‐PAA, PAA‐block‐PAI, and homo‐PAA. In the dry state, aggregates of CNT are observed by transmission electron microscopy (TEM) in the mixture with PAA‐block‐PAI and homo‐PAA. The adhesion of the copolymers to CNT is also observed by TEM and is due to the high affinity between hydrophobic PAI and CNT. In particular, PAA₂PAI and PAA‐block‐PAI‐block‐PAA well cover the CNTs. The presence of PAI and the PAA location are important for the dispersion of CNTs. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43461.     

NO/CH4 Reaction over Nanodispersed Pt Particles

The catalytic behavior of the cubic (70%) Pt nanoparticles supported on alumina, with an average diameter of 132nm, was investigated for NO/CH₄ reaction. It was observed that the formation of reaction products (N₂O, CO and NH₃) is related to the size as well to the shape (facet) of the Pt nanoparticles.     

Bending of poly(vinyl alcohol)–poly(sodium acrylate) composite hydrogel in electric fields

Bending of poly(vinyl alcohol) hydrogel mixed with poly(sodium acrylate) chains, PVA–PAA gel, under the influence of dc electric fields was studied. The PVA–PAA gel was prepared by repeatedly freezing and thawing a mixture of PVA and polyacrylic acid aqueous solutions. The PVA–PAA gel was a hydrogel with the PAA chains, which were entangled with the PVA polymer network and were fixed in the gel. The PVA–PAA gel bent toward the negative electrode in electrolyte solutions under dc electric fields as did the polyelectrolyte gel with negatively charged polyions. The PVA gel, free of PAA, was insensitive to dc electric fields. The deflection of the bending and the bending speed were influenced by the filed intensity, the concentration of the polyion in the gel, and the thickness of the gel. The bending of the PVA–PAA gel was qualitatively explained by a bending theory of polyelectrolyte gel, based upon the change of the osmotic pressure due to the ion concentration difference between the inside and the outside of the gel.     

Poly(ADP-ribose) Polymerase 1 Mediates Rab5 Inactivation after DNA Damage

Parthanatos is programmed cell death mediated by poly(ADP-ribose) polymerase 1 (PARP1) after DNA damage. PARP1 acts by catalyzing the transfer of poly(ADP-ribose) (PAR) polymers to various nuclear proteins. PAR is subsequently cleaved, generating protein-free PAR polymers, which are translocated to the cytoplasm where they associate with cytoplasmic and mitochondrial proteins, altering their functions and leading to cell death. Proteomic studies revealed that several proteins involved in endocytosis bind PAR after PARP1 activation, suggesting endocytosis may be affected by the parthanatos process. Endocytosis is a mechanism for cellular uptake of membrane-impermeant nutrients. Rab5, a small G-protein, is associated with the plasma membrane and early endosomes. Once activated by binding GTP, Rab5 recruits its effectors to early endosomes and regulates their fusion. Here, we report that after DNA damage, PARP1-generated PAR binds to Rab5, suppressing its activity. As a result, Rab5 is dissociated from endosomal vesicles, inhibiting the uptake of membrane-impermeant nutrients. This PARP1-dependent inhibition of nutrient uptake leads to cell starvation and death. It thus appears that this mechanism may represent a novel parthanatos pathway.