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The free radical scavenger edaravone is able to stimulate prostacyclin release and inhibit the lipoxygenase pathway in the arachidonic acid cascade. The effect of edaravone administration on myocardial damage in rabbit hearts subjected to ischaemia–reperfusion was examined at different times relative to reperfusion. All rabbits underwent sustained coronary artery occlusion for 30 min followed by 3 h of reperfusion. Rabbits were divided into the following groups: control; early (3 mg/kg edaravone IV 10 min before reperfusion); immediate (3 mg/kg edaravone IV immediately after the start of reperfusion); and late (3, 6 or 10 mg/kg edaravone IV 5 min after the start of reperfusion). Single bolus administration of edaravone 10 min before reperfusion or immediately upon initiation of reperfusion appears to be associated with reductions in infarction size and the percentage of apoptotic cells, but treatment with edaravone 5 min after initiation of reperfusion does not appear to have this protective effect.

Macroscopic and microscopic dissipative structural patterns form in the course of drying a series of aqueous solutions of polyoxyethylenealkyl ethers. The shift from the single round hill with accumulated surfactant molecules to the broad ring patterns of the hill in a macroscopic scale occurs as the HLB (hydrophile−liophile balance) of the surfactant molecules increases. The patterns correlate intimately with the HLB values of the surfactants. Microscopic patterns of small blocks, starlike patterns, and branched strings are formed. The size and shape of the surfactant molecules themselves influence the drying patterns in part. The pattern area and the time to dryness have been discussed as a function of surfactant concentration and HLB of the surfactants. The convection flow of water accompanying the surfactant molecules, the change in the contact angles at the drying frontier between solution and substrate in the course of dryness, and interactions among the surfactants and substrate are important for the macroscopic pattern formation. Microscopic patterns are determined in part by the shape and size of the molecules, translational Brownian movement of the surfactant molecules, and the electrostatic and hydrophobic interactions between surfactants and/or between the surfactant and substrate in the course of solidification.

We have developed an economical and environmentally benign process for the fabrication of mesoporous silica films. The approach involves redispersion of the as-synthesized silica−surfactant hybrid in an organic solvent to form the transparent coating sol. The sol provided a much wider processing time window for the films, and ordered mesoporous silica films could be fabricated even after storing the sol for a long period of time. The key feature of this work is that the uncontrolled silica condensation, proceeding during drying, in the as-synthesized silica−surfactant hybrid is arrested by redispersing it in an inert organic solvent.

Macroscopic and microscopic dissipative structural patterns are formed in the course of drying an aqueous solution of n-dodecyltrimethylammonium chloride on a cover glass. Broad ring patterns of the hill accumulate with detergent molecules to form around the outside edges of the film solution in the macroscopic scale. The drying time ( T) and the pattern area ( S) decrease and increase respectively, as the detergent concentration increases. T decreases significantly as the ethanol fraction increases in the aqueous ethanol mixtures, whereas S increases as the fraction increases. Both T and S decrease as the concentrations of KCl, CaCl 2 or LaCl 3 increase. Cross-, branch-, and arc-like microscopic patterns are observed in the separated block regions. The convection of water and detergents at different rates under gravity and the translational and rotational Brownian movement of the latter are important for macroscopic pattern formation. Microscopic patterns are determined by the translational Brownian diffusion of the detergent molecules and the electrostatic and the hydrophobic interactions between the detergents and/or between the detergent and cell wall in the course of the solidification.

Oligomeric Zn3ppo6, where ppo is 2-(2-hydroxyphenyl)-5-phenyl-1,3-oxazole, has been synthesized as a new blue-emitting material for organic light-emitting diodes (OLEDs). The electroluminescence maximum wavelength is 450 nm and the Commission Internationale de l'Eclairage (CIE) coordinates are x = 0.15, y = 0.11 for blue chromaticity. The luminance efficiency and the maximum luminance were about 1.3 lm/W at 6 V, 5.8 mA/cm² (139 cd/m²), and 8140 cd/m² at 11.4 V. Zn3ppo6 shows two trimeric polymorphs and a monomeric structure at different sublimation temperatures.

A rheo-optical study on the colloidal alloys of binary mixture of silica spheres (110 and 300 nm in diameter) has been made in an exhaustively deionized suspension. The shear stress shows the yielding in the stress−strain measurements. The intersphere spacings increase first and reach a constant value as strain increases, whereas they decrease for the crystals of single-component spheres. The yielding phenomena in the stress−strain profiles were observed for all colloidal crystals of single-component spheres and colloidal alloys. The strain dependences on the peak wavelength and intensity in the reflection spectroscopy quite differ between colloidal crystals and alloys. The distortion of the colloidal alloys occurs at small shear stress and/or shear rate. The distortion of the electrical double layers, the sliding of the crystal planes, and the partial melting of the crystal structure are supported at rather high shear stresses and/or rates. Rheological properties in the steady-shear measurements of colloidal alloys are really crystal-like.

Faujasite zeolite is synthesized hydrothermally after an aging process under various conditions. Hydrogel is formed during the aging, and the amount increases with increasing the duration. Aluminosilicate species included in the hydrogel phase during the aging is investigated for the changes in Si/Al ratios and Q units during the aging and the crystallizing processes by means of ²⁹Si magic-angle spinning NMR spectroscopy. Aging for more than 1 day is necessary to obtain faujasite with high crystallinity. The distribution in Q⁴ units in the hydrogel is gradually changed, and the aluminosilicate species having mainly a Q⁴(4Al) unit is obtained after 7 days of aging, while 2 days of aging results in remanent silicate species derived from the starting silica source. The former gives faujasite crystallites with higher crystallinity, sharper particle size distribution, and a lower Si/Al ratio. On the basis of these findings, the crystallization mechanism is discussed.

Structure, crystal growth kinetics, and rigidity of thermosensitive colloidal crystals formed from mixtures of colloidal silica spheres (diameter, 103 nm) and gel spheres of poly(N-isopropylacrylamide) are studied mainly from reflection spectroscopy. The gel spheres change their hydrodynamic size transitionally at 35 °C from 72 nm (at 20 °C) to 28 nm (at 45 °C). The mixtures are deionized exhaustively with ion-exchange resins in aqueous suspensions. In the absence of gel spheres, intersphere spacings of the crystals, lobs, are quite insensitive to suspension temperatures ranging from 15 to 55 °C. In the presence of the gel spheres, on the other hand, the lobs value decreases transitionally at 35 °C when suspension temperature increases. The ζ-potential and the effective diameter of colloidal silica spheres determined by electrophoretic light-scattering measurements increase as the gel concentration increases. Addition of the gel spheres decreases the crystal growth rate and increases the rigidity of the mixtures. These results support strongly that the thermosensitive gel spheres adsorb weakly onto the surface of colloidal silica spheres.

A novel TTF-based donor with a uracil moiety, TTF-(1-n-butyluracil-5-yl) (TnbU), was synthesized. Crystal structures of both TnbU and the charge-transfer complex of TnbU−hydrogen cyananilate possess complementary double hydrogen bonds through uracil moieties and π-stacking dimer structures between TTF skeletons. Furthermore, the TnbU−TCNQ charge-transfer complex shows a high electrical conductivity underlying the partial charge-transfer accompanied by a hydrogen-bonding interaction, which was substantiated in terms of the measurements of the IR, electronic spectra, and conductivity.

Magnetic resonance imaging (MRI) is useful to diagnose dural sinus thrombosis. However, the representative appearance of dural sinus thrombosis on diffusion-weighted MRI has not been established. This study was aimed at determining whether cytotoxic or vasogenic edema is more predominant in the affected cerebral parenchyma and assessing the time courses and prognosis of dural sinus thrombosis lesion. The studies on sixteen patients with dural sinus thrombosis who underwent diffusion-weighted MRI were retrospectively reviewed. The diagnosis was confirmed by digital subtraction angiography in 11 patients and magnetic resonance angiography in five patients. Diffusion-weighted images with echo-planar imaging were obtained using two or three b values, with the highest b value of up to 1,000 s/mm2. A region of interest was placed on an area of abnormal signal intensity to calculate apparent diffusion coefficients (ADCs). Nine of the 16 patients had lesions with an increased ADC, whereas, three of these nine patients also had lesions with a decreased ADC. Among 11 patients who underwent initial MRI within 7 days of their last episode, eight had lesions with an increased ADC, of whom three had lesions mixed with both decreased and increased ADC areas. Follow-up studies of these three patients revealed the development of hemorrhagic infarction in two and subcortical hemorrhage in one. Vasogenic edema develops more predominantly and earlier in dural sinus thrombosis, though cytotoxic edema was also associated with the pathological changes in the early phase. Decrease of ADC value is presumed to reflect severe pathological conditions and indicate possible future development of infarction or hemorrhage.

Abstract: Kinetic analyses were made for the seed polymerization of tetraethyl orthosilicate (TEOS) in the presence of colloidal silica sphere seeds by turbidity and dynamic light scattering (DLS) measurements. Transmission electron microscopy (TEM) of the spheres formed was also used. TEOS is polymerized exclusively on the surfaces of the seed spheres, their sizes ranging from 29 to 184 nm in diameter. The sphere size versus time and the cube root of the absorbance versus time from DLS and turbidity measurements agree well, especially in the beginning of the reaction. The seed polymerization starts immediately on the addition of seed spheres, though the polymerization in the absence of the seeds proceeds after a certain induction time ranging several tens of seconds to several minutes. The polymerization rates of the reaction increase when the size and/or the concentration of the seed spheres increases. The thickness of the TEOS layers formed on the seed surfaces increases as the seed size increases; this is confirmed by the TEM pictures. These results are consistent with the polymerization mechanism of the formation of small preliminary particles followed by their coalescence on the surfaces of seeds to the final large spheres coated with silica layers.

Abstract: Rigidities of colloidal alloys of binary mixtures of colloidal silica spheres (CS82; 103 nm in diameter) with larger silica spheres (CS91; 110 nm, CS121; 136 nm and CS161; 184 nm) have been measured by reflection spectroscopy in sedimentation equilibrium. Substitutional-solid-solution-type alloy structures are formed for mixtures of CS82 and CS91 and for CS82 and CS121. A superlattice, probably MgCu2 type, is formed for CS82 and CS161 mixtures. The rigidities of the colloidal crystals of the single component of the spheres increase as the sphere size increases at the same number density of spheres. The rigidities of the colloidal alloys decrease when a comparatively small number of the larger spheres are mixed with the small spheres at the same total sphere number density.

Abstract: Rotational relaxation times (τ) of anisotropic tungstic acid colloids in aqueous suspension containing sodium chloride or ethyl alcohol are studied in microgravity achieved by free-fall experiments. Experimental errors at 0 G, in many cases, are small compared with those at 1 G, which is ascribed to the lack of the convection of suspension in microgravity. Much more reliable data of the diffusion coefficients are obtained in microgravity. The limiting slopes of the relaxation curves in the plots of the transmitted-light intensity against time at 1 G depend on the flow direction of the suspension in the flow cell, whereas those at 0 G are close to zero irrespective of the flow direction. Sodium chloride decreases τ, whereas ethanol addition increases this time. These effects are ascribed to the thinning of the electrical double layers and to the increase in the suspension viscosity.

A series of calcined borosilicate molecular sieves are treated hydrothermally with aqueous acetic acid and subsequently characterized in detail. The acid treatments are shown to expel boron from the molecular sieves, and the defects created by the boron removal are subsequently healed with silicon dissolved from other parts of the crystal. By use of this procedure, highly crystalline, hydrophobic all-silica CIT-1 and SSZ-33 (CON topology) molecular sieves are synthesized for the first time. ²⁹Si Bloch decay (BD) and cross-polarization magic-angle spinning (CPMAS) NMR spectra indicate that the materials have few internal defects and allow for structural characterization of CON materials by ²⁹Si MAS NMR. Seven unique tetrahedral silicon species are identified in the spectra in agreement with the published crystal structure. The effects of treatment conditions such as acid type, solution pH, and temperature are studied in detail. Conditions near the isoelectric point of silica (pH = 0−2) are found to be efficient for the production of a variety of hydrophobic materials with few structural defects including molecular sieves of the *BEA, CON, and MWW topologies. Detailed control studies using SSZ-33 show that the nearly defect-free materials contain triangular mesopores that are clearly distinguishable in field-emission electron microscopy images. The silica that previously inhabited the mesopores is a likely source for the species required to heal the defects created by boron expulsion. In addition to healing the vacancies previously inhabited by boron with dissolved silicon, an additional aluminum or gallium source can be added to the acetic acid solution and the ions are incorporated into the framework. Many of the defects that are not filled with the Al³⁺ or Ga³⁺ species are filled with silicon during the treatment to produce a more hydrophobic metallosilicate than the one containing internal silanol defects.

Abstract:  Rate coefficients (k) in the colloidal crystallization of monodispersed silica spheres in the presence of sodium chloride are studied in microgravity achieved by parabolic flights of an aircraft. Time-resolved reflection spectroscopy is made with a continuous circulating-type stopped-flow cell system. The k values decrease as the salt concentration increases both at 0 and 1 G and those in microgravity are smaller than those in normal gravity by 16% (maximum), especially in water and in the presence of a small amount of the salt lower than 2 × 10−6 mol/l. The rates in flight at 1 G are larger by 15% (maximum) compared with those at 1 G on the ground. The k values obtained at 0 G, 1 G in flight and 1 G on the ground agree excellently with each other for the suspensions with 3 × 10−6 and 4 × 10−6 mol/l sodium chloride. Disappearance of the downward diffusion of spheres and no convection of the suspensions are important for retardation in microgravity.

Abstract:  Viscosities of exhaustively deionized aqueous suspensions of colloidal silica spheres are measured with coexisting ion-exchange resins using an Ubbelohde-type viscometer. The reduced viscosities of small silica spheres (56.3 nm in diameter) with and without resins decrease as the sphere concentration increases. However, the former are larger than the latter especially at low sphere concentrations. The reduced viscosities of other silica spheres, 81.2, 103, 110 and 136 nm in diameter, with resins decrease as the sphere concentration increases, whereas those without resins increase especially at low sphere concentrations. The significant effect of the extent of deionization upon the viscometric properties supports the important role of the extended electrical double layers formed around the colloidal spheres.

Abstract:  Gigantic colloidal single crystals (2–6 mm) are formed for fluorine-containing polymer spheres (120–210 nm in diameter) in exhaustively deionized aqueous suspensions. The spheres used are poly(tetrafluoroethylene) (PTFEA and PTFEB), copolymer of tetrafluoroethylene and perfluorovinylether (PFA) and copolymer of tetrafluoroethylene and perfluoropropylene (PTP). The phase diagrams of these spheres are obtained in the deionized suspensions and also in the presence of sodium chloride for PFA. The critical sphere concentrations of crystal melting (φ c) for these spheres are around 0.0006 in volume fraction, which are close to, but slightly larger than, those of monodispersed polystyrene spheres (φ c ≈ 0.00015) and colloidal silica spheres(φ c = 0.0002–0.0004) reported previously. The crystals are largest when the sphere concentrations are a bit higher than the φ c value and their size decreases as the sphere concentration increases. Reflection spectra are taken in sedimentation equilibrium as a function of the height from the bottom of the suspension. The static elastic modulus is estimated to be 10.8 and 28.7 Pa for PTFEA and PTP spheres at the sphere concentrations 0.00325 and 0.00322 in volume fraction, respectively.

Pervaporation and gas permeation properties of microporous silica membranes made by a sol−gel method are discussed. Defect free molecular sieving membranes are prepared by a dip coating process. The molecular sieving performance was measured and controlled based on gas permeation behavior of the membranes. The apparent activation energy for helium permeation and He/N2 perm-selectivity values were used as the parameters for optimization of the membrane performance. The membranes with very high activation energy for He diffusion were used for pervaporation studies with a methanol/MTBE mixture at 323 K. Separation factor values as high as 260 were measured at a total liquid flux of 0.3 kg/m² hr. Sorption studies performed on corresponding silica gels revealed a separation mechanism based on diffusion of vapor molecules. Permeation of the vapor molecules through the micropores followed an activated diffusion mechanism. The gas permeation data could provide an understanding of the pore size distribution of the membrane, and the vapor sorption and diffusion data on the size and connectivity of the membrane pores.

Abstract: Alternate multiple adsorbed layers of up to six macrocations [poly(4-vinyl-N-n-butyl-pyridinium bromide)] and macroanions [sodium poly(styrene sulfonate)] are formed on monodispersed polystyrene colloidal spheres above the critical concentration of the macroions, m *. The m * value is the minimum number of macroions needed to reverse the sign of the ζ potential of the spheres in the first adsorption step. Alternate sign reversal in the ζ potential and expansive–contractive thickness changes are observed on the repeated and alternate addition of macrocations first and macroanions next. When the macroanions are added first, sign reversal in the ζ potential and reversible expansion and contraction do not occur. Breaking of the alternate multiple-type adsorption also occurs when equivalency in the number of dissociative groups of macrocations and macroanions is broken. Synchronous conformational changes of macrocations and macroanions in the multiple-adsorbed layers occurs only when the conformational rigidities with the multiple electrostatic and hydrophobic attraction and/or repulsion between macrocations and macroanions are delicately balanced.

Abstract:  Crystal growth rates in colloidal alloy crystallization of binary mixtures of monodispersed polystyrene and/or silica spheres having different sizes and densities are studied in microgravity by parabolic flights of an aircraft. The crystal growth rates are obtained by time-resolved reflection spectroscopy with a continuous circulating-type stopped-flow-cell system. The growth rates of alloy crystallization increase substantially in microgravity up to about 1.7 times those in normal gravity, which is in contrast to the retarding microgravity effect on the crystallization of single-component spheres. The disappearance of the segregation effect in microgravity is the main cause for the enhancing effect. The absence of convection of the suspension and the lack of downward sedimentation of colloidal spheres are also important.

Abstract: Time-resolved reflection spectroscopic measurements are made for the kinetic analyses of the nucleation and growth processes of soft-type colloidal crystals of silica spheres (110 nm in diameter) in the presence of sodium chloride. Fast-scanning reflection spectra are taken using a continuous circulating-type stopped-flow cell system. The cell system is composed of a peristaltic pump and a quartz flow cell, which are connected with a PharMed tube in a closed circuit. The volume fraction of the spheres is 0.028. Induction periods range from 0.2 to 1.3 s and increase as salt concentration increases. Nucleation rates are 1  104 to 7  104 spheres/mm3s and decrease as salt concentration increases. The crystallization process has been observed from the sharpening and the increase in intensity of the reflection peaks. The crystal growth rate in the absence of salt is 23 μm/s, and decreases as salt concentration increases. The importance of electrostatic intersphere repulsion through the electrical double layers and the cooperative and synchronous fluctuation of colloidal spheres in the crystallization processes is supported.