Traumatic biliary stricture successfully treated by percutaneous transhepatic bile duct dilatation: a case report

A 24 year-old woman complained of obstructive jaundice 24 days after blunt abdominal trauma due to a traffic accident. Endoscopic retrograde cholangiopancreatography (ERCP) revealed a stricture, 15 mm in length, at the common bile duct associated with upper bile duct dilatation. Jaundice was reduced by percutaneous transhepatic cholangio-drainage (PTCD). A 7 Fr-sized PTCD tube was exchanged for a larger-sized catheter for percutaneous transhepatic cholangioscopy expecting gradual dilatation of the stricture. Following the confirmation of satisfactory dilatation of the stricture, the catheter was removed. There was no recurrence of jaundice 16 months later in a follow-up study.     

Structural control of core/shell polystyrene microcapsule‐immobilized microbial cells and their application to polymeric microbioreactors

Polystyrene microcapsules possessing a large single core and highly microporous wall were prepared as immobilization supports for microbial cells by a new method based on phase separation of polystyrene within a mixed organic solvent system in an oil‐in‐water (o/w) emulsion. The structures of core and micropore were controlled by changing the concentration of isooctane in the organic phase and the temperature of solvent evaporation. The immobilization of baker's yeast into the polystyrene microcapsules was carried out by entrapping the yeast into calcium alginate beads before encapsulating in the microcapsules and followed by removing the beads with HCl solution. The morphology of the microcapsules was observed by means of SEM, and the activity of the immobilized yeast was evaluated by using the microcapsules in ethanol fermentation. It was found that the formation of the core and wall pore was remarkably influenced by the isooctane concentration, and the diameter of the core was affected by the temperature of solvent evaporation. The yeast was successfully immobilized into the polystyrene microcapsules at a high density and a high catalyst activity by the proposed immobilization method. Furthermore, the polystyrene microcapsules exhibited a high operational stability in the repeated batchwise fermentation test. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1966–1975, 2003     

Full-Scale Experimental Investigation to Quantify Building Component Ignition Vulnerability from Mulch Beds Attacked by Firebrand Showers

Structure ignition by wind-driven firebrand showers is an important fire spread mechanism in large outdoor fires. Experiments were conducted with three common mulch types (shredded hardwood mulch, Japanese Cypress wood chips, and pine bark nuggets) placed adjacent to realistic-scale re-entrant corners. In the first series of experiments, mulch beds were placed adjacent to a re-entrant corner constructed with wood studs and lined with oriented strand board (OSB) as the sheathing. The premise behind conducting experiments with no siding treatments applied was predicated on the notion that bare OSB mulch contact would be a worst-case scenario, and therefore, a wall assembly in the most vulnerable state to mulch ignition. In the second series of experiments, vinyl siding was applied to the re-entrant corner assemblies (wood studs/OSB/moisture barrier/vinyl siding), and the influence of vertical separation distance (102 mm or 203 mm) on wall ignition from adjacent mulch beds was determined. The vertical separation distance was maintained by applying gypsum board to the base of the re-entrant corner. The siding itself did not influence the ignition process for the mulch beds, as the mulch beds were the first to ignite from the firebrand showers. In all experiments, it was observed that firebrands produced smoldering ignition in the mulch beds, this transitioned to flaming ignition, and the re-entrant corner assembly was exposed to the flaming mulch beds. With no siding treatments applied, the flaming mulch beds ignited the re-entrant corner, and ignition was observed to propagate to the back side of re-entrant corner assembly under all wind speeds (6 m/s to 8 m/s). With respect to the re-entrant corners fitted with vinyl siding, the mulch type, vertical separation distance, and wind speed were important parameters as to whether flaming ignition was observed to propagate to the back-side of a re-entrant corner assembly. Mulches clearly pose an ignition hazard to structures in large outdoor fires.     

Crystallization and some properties of D-lactate dehydrogenase from Staphylococcus sp. LDH-1

Staphylococcus sp. LDH-1 isolated as a high producer of lactate dehydrogenase grew well under anaerobic conditions and produced a large amount of D-lactate dehydrogenase (D-LDH), but not L-LDH. After purification of this D-LDH, some properties were revealed. The enzyme catalyzed the reversible reduction of 2-oxo acids into D-2-hydroxy acids, but not into L-2-hydroxy acids. The K(m) values for 2-oxo acids were much smaller than those for D-2-hydroxy acids, and the V(max) values for 2-oxo acids were much greater than those for D-2-hydroxy acids. The equilibrium constants for the reaction of the reductions of pyruvic acid to D-lactic acid and of 2-oxobutyric acid to D-2-hydroxy-n-butyric acid were 270 and 360, respectively. The enzyme was stable between pH 5.5 and 8.5, while the optimum pH for pyruvic acid and D-lactic acid was pH 5.0 and 8.2, respectively. It was therefore concluded that the D-LDH from Staphylococcus sp. LDH-1 is available as enzyme for an assay of pyruvic acid and for the production of D-2-hydroxy acids.     

Reducing vancomycin use utilizing a computer guideline: results of a randomized controlled trial

Normal development and hypoxic-ischemic changes of glutamate-aspartate transporters (GLAST) and excitatory amino acid transporter type 4 (EAAT4) were demonstrated in the human cerebellum. GLAST-immunoreactive Bergmann's glia and EAAT4-positive Purkinje cells showed a specific distribution and localization, and developed with age in the molecular and Purkinje cell layers. The dendrites and cell bodies of Purkinje cells, which showed EAAT4 immunoreactivity, were ensheathed by GLAST processes. In neonatal hypoxic-ischemic encephalopathy (HIE), GLAST immunoreactivity decreased in the molecular layer and increased in the inner granule cell layer at an early stage, and markedly increased in the Purkinje and inner granule cell layers at a late stage. EAAT4 immunoreactivity decreased with post-ischemic changes of Purkinje cells. GLAST reactivity changed more rapidly than EAAT4 in cases of HIE. These changes of GLAST and EAAT4 may be closely related to the vulnerability of Purkinje cells in hypoxia-ischemia. The glutamate transporter of Bergmann glia may play a more important role in the regulation of the extracellular glutamate concentration in hypoxia and/or ischemia.     

Fabrication of a Composite Varistor with Electrical Conductive Ni Filler and Electrostriction PNZST Matrix

A composite varistor was fabricated using Ni powder as conductive filler and PNZST antiferroelectric powder as electrostriction matrix. The composite is an electrical insulating material when an electrical field is not applied. When the electrical field was applied to the composite, the PNZST powder matrix was distorted. A conduction path was formed in the composite because of the distortion of the electrostriction matrix and thus the composite became a conductive material when the electrical field was applied. Composites using an Ni filler with 4-μm particle size and a PNZST matrix with 2-μm particle size showed a varistor property with volume fractions 33% and 37%; the nonlinearity coefficients of the composites were 3.85 and 3.82. The composites using an Ni filler with 40-μm particle size and a PNZST matrix with 2-μm particle size also showed varistor properties with volume fractions 50% and 53%, and nonlinearity coefficients of the composites were 3.65 and 3.12.     

Effect of rheological behavior of epoxy during precuring on foaming

In this study, the effect of rheological behavior of epoxy during precuring on foaming was investigated. Dynamic time sweep test of epoxy/curing agent (100/1, w/w) was conducted. The viscosities as a function of time showed extremely rapid increase from the order of 10²–10³ to 10⁶Pa · s at a certain time, followed by slow increase of the viscosities. Dynamic frequency sweep test of precured epoxy with curing agent was conducted at 90°C. The critical gelation time was obtained by using rheological criterion proposed by Winter and Chambon. We found that the slopes of G′(ω) and G″(ω) decreased with increasing precuring time. Correspondingly, tan δ showed a change from negative to positive slope at a critical time. By using the results, the critical gelation time was determined as t = 895–935 s. Samples of epoxy/curing agent/blowing agent (100/1/0.5) were precured for 960–1620 s. And then precured samples were foamed at 230°C for 300 s to decompose chemical blowing agent. The formed bubble size distribution becomes sharp with increase of the precuring time. There are roughly two sizes of bubbles when precured for relatively short time (t < 1080 s) before foaming: large bubbles (>100 μm) and small ones (?30 μm). On the other hand, foams precured for long time (t > 1200 s) before foaming, large bubbles disappear, and the average diameter of the bubble becomes small while the porosity is low. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Hydrotalcites Catalyze the Acidolysis Polymerization of Phenolic Acid to Create Highly Heat‐Resistant Bioplastics

Acidolysis polymerization has been used to prepare phenol‐derived polymers such as liquid crystalline (LC) polymers, and is catalyzed by mildly‐alkaline salts. The catalytic effects of hydrotalcites (HTs), which are natural alkalescent minerals with controllable basicity, are investigated on the acidolysis copolymerization of coumarates such as p‐coumaric acid and caffeic acid. As a result, the LC copolymer prepared in the presence of HT with a Mg/Al ratio of 3 shows higher molecular weight values than copolymers prepared in the presence of any other alkalescent salts. On the other hand, the copolymers prepared in the presence of HTs show a clear LC state where the polymer chains are oriented on the surface of the glass fibers. The resin, which is oriented by glass fiber fillers aligning along its longitudinal axis and is annealed at 300 °C for 20 min, shows a softening temperature of 305 °C while keeping a high mechanical strength of 85 MPa and a high mechanical modulus over 1 GPa.     

CMAS degradation of ytterbium aluminum garnets

The degradation of ytterbium aluminum garnet (YbAG) exposed to molten Ca–Mg–Fe–Al–Si–O (CMAS) at 1673 K was investigated for two kinds of dense polycrystalline YbAG with compositions deviating slightly from stoichiometry, referred to as Al- and Yb-rich. The mitigation of the CMAS attack for Yb-rich YbAG was markedly superior to that for the Al-rich one. For both types of YbAG, corrosion progressed due to the preferential penetration of the CMAS melt along grain boundaries in the thickness direction and the simultaneous dissolution of crystal grains into the melt. The lower of the corroded region consisted of YbAG crystals with a core/shell-I/shell-II structure. Shell-I contained alkaline earth, silicon, and iron cations, whereas these cations were hardly detected in shell-II. Growth of the shell-I region was considered to progress by dissolution and reprecipitation through the melt existing around it, and finally, the melt disappeared, resulting in the formation of a thin shell-II region containing little of these ions. The formation and growth of the shell-I region were found to be promoted by making the YbAG Yb-rich, resulting in enhancement of the resistance to CMAS.