Preparation of pyrochlores. A1−xHxTaO3·nH2O (A=Na,K)

Pyrochlores of A_1?xH_xTaO₃·nH₂O (A=Na,K) were prepared under the hydrothermal conditions. The values of x for these compounds were increased from 0.3 to 0.5 for A=Na and from 0.2 to 0.5 for A=K by treatment with the distilled water. The compounds with x<0.5 were decomposed to a mixture of NaTaO₃ and Na₂Ta₄O₁₁ for A=Na, or to a mixture of KTaO₃ and a tetragonal tungsten bronze phase, and those with x=0.5 to a single phase of A₂Ta₄O₁₁ at elevated temperatures. Below the decomposition temperatures, defect pyrochlores with oxygen vacancies, $\text{A}{}_{\mathrm{<mtext>1?</mtext><mtext>x</mtext>}}\text{TaO}{}_{\mathrm{<mtext>3?</mtext><mtext>x</mtext><mtext>2</mtext>}}$, were produced. They were hygroscopic, and in the case of A=K and x=0.5 the original phase was recovered by leaving in air for several hours.     

Proposed method for measuring local heat transfer coefficients of isothermal surfaces

A method has been proposed for measuring local heat transfer coefficient. The method uses the change of wet surface temperature by radiation heating and can be applied to the isothermal condition and the large variation of the local heat transfer coefficient along the surface of a body. The present method is based on the heat balance equation, which expresses a simple relationship between humidity and wet-bulb temperature. An experiment was devised to measure the local heat transfer coefficient of a flat plate. The results confirmed the effectiveness of the present method to measure the local heat transfer coefficient with reasonable accuracy.     

Ion exchange of intercalation compounds from WOP2O7 and intercalation ofn-alkylamines

Ion exchange of Na _x WOP₂O₇ ·nH₂O (x 1.4) prepared from WOP₂O₇ was attempted, using alkaline and alkaline earth ions. The degree of exchange was observed to be >50% at 90° C except for Mg²⁺. The basal spacing of ion-exchanged materials for the hydrated phase were dependent on the number of water molecules in the interlayer spaces, while those for the dehydrated phase increased with the size of ions in the interlayer spaces. The network of water molecules linked by the hydrogen bond in the interlayer spaces seems to determine the basal spacing. By the ion-exchange reaction,n-alkylammonium ions were intercalated into the interlayer spaces of Na _x WOP₂O₇ ·nH₂O (x 1.4) and Sn _x H _y WOP₂O₇ ·nH₂O (2x +y 0.5). In spite of the difference in the charge density of the host layer, a similar arrangement of alkyl chains in the interlayer spaces resulted, and neutral amines were considered to be intercalated as well as ammonium ions. Direct reaction ofn-alkylamine with WOP₂O₇ produced an intercalation compound without reduction of tungsten. The arrangement of the amines in the interlayer spaces is similar to that supposed to the ion-exchanged derivatives when heated at 140° Cin vacuo.     

Doped Helium Crystals Growth and Study

No Heading The new technique for embedding microimpurities into solid helium has been developed. A He crystal was grown in a vertical cylindrical cell placed in the bath of pumped LHe cryostat. The He solid was continuously moved downward by exhaust of helium from the cell bottom and was simultaneously restored from its upper edge by sedimentation of a jet of gas helium mixed with impurity. A guest particle density of 3· 10¹⁹ per cc and stable during an hour doped crystal growth with the rate of 1 mm per 20 s were achieved. The solid Deuterium clusters isolated in solid Helium have been investigated at T = 1.3K and P = 3 MPa by CARS technique. The strong effect of Raman scattering sensitivity to the molecular environment nuclear spin has been found in CARS - the ratio of probabilities for the scattering by para (J=1) and ortho (J=0) deuterium being equal to 1 in a gas is as high as 10,000 in nearly pure o-D₂, whereas it is 50 in common Raman scattering. This effect has been shown to give rise starting from cluster size corresponding to the phonon band onset.PACS numbers: 33.20 Fb; 33.70 Jg: 67.80 Mg     

Very low threshold current density of 1.3-/spl mu/m-range GaInNAsSb-GaNAs3 and 5 QWs lasers

The dependence of the threshold current density on the number of wells for 1.3-/spl mu/m-range edge emitting lasers using GaInNAsSb novel material, at which the incorporation of the small amount of Sb make the two-dimensional growth condition wide, is studied. The lowest record ever reported for the threshold current density per well (Jth A/cm/sup 2//well@L=900 /spl mu/m) for 3 QWs lasers was achieved. GaInNAs-based 5 QWs lasers with the very low threshold current density per well of 160 A/cm/sup 2/ were successfully grown for the first time. Therefore, no significant deterioration of Jth is observed even though the number of wells increased up to 5. Since Jth of 5 QWs doesn't increased rapidly compared to SQW and 3 QWs as decreasing the cavity length, it is considered that lower Jth can be obtained by utilizing 5 QWs in devices such VCSELs which use short cavity length.     

Modeling of quantitative relationships between physicochemical properties of active pharmaceutical ingredients and tensile strength of tablets using a boosted tree

Objectives: The aim of this study was to explore the potential of boosted tree (BT) to develop a correlation model between active pharmaceutical ingredient (API) characteristics and a tensile strength (TS) of tablets as critical quality attributes.

Methods: First, we evaluated 81 kinds of API characteristics, such as particle size distribution, bulk density, tapped density, Hausner ratio, moisture content, elastic recovery, molecular weight, and partition coefficient. Next, we prepared tablets containing 50% API, 49% microcrystalline cellulose, and 1% magnesium stearate using direct compression at 6, 8, and 10?kN, and measured TS. Then, we applied BT to our dataset to develop a correlation model. Finally, the constructed BT model was validated using k-fold cross-validation.

Results: Results showed that the BT model achieved high-performance statistics, whereas multiple regression analysis resulted in poor estimations. Sensitivity analysis of the BT model revealed that diameter of powder particles at the 10th percentile of the cumulative percentage size distribution was the most crucial factor for TS. In addition, the influences of moisture content, partition coefficients, and modal diameter were appreciably meaningful factors.

Conclusions: This study demonstrates that BT model could provide comprehensive understanding of the latent structure underlying APIs and TS of tablets.     

Characterization of alternative plasticizers in poly(vinyl chloride) sheets for blood containers

This study aimed to optimize the ratio of dioctyl 4‐cyclohexene‐1,2‐dicarboxylate (DOTH) and di‐isononyl‐cyclohexane‐1,2‐dicarboxylate (DINCH^®) for use as plasticizers in poly(vinyl chloride) (PVC) sheets. We also evaluated the biological safety of DOTH for its potential to be part of a safe PVC‐based blood container. The suppression of hemolysis in mannitol‐adenine‐phosphate / red cell concentrates (MAP/RCC) with DOTH/(DINCH^®‐PVC) sheets and the elution of plasticizers from the sheets increased with higher DOTH compositions. The properties of the PVC sheet containing DOTH and DINCH^® in the ratio of 25:33 parts against PVC 100 parts as a weight were almost identical to the PVC sheet made of di(2‐ethylhexyl) phthalate. From a subchronic toxicity test, DOTH did not show any adverse effects on all organs, including the testes, epididymis, liver, and kidneys. The no‐observed‐adverse‐effect level was 300 mg/kg body weight/day in a rat. These results suggest that DOTH/DINCH^® (25:33) is a promising candidate for the replacement of di(2‐ethylhexyl) phthalate in blood containers. J. VINYL ADDIT. TECHNOL., 22:520–528, 2016. © 2015 Society of Plastics Engineers     

Template-free hydrothermal synthesis of hollow hematite microspheres

Hollow hematite (α-Fe₂O₃) microspheres with an average diameter of 3-4 μm and a shell thickness of approximate 150 nm was synthesized by a simple hydrothermal route using FeCl₃·6H₂O solution and acetic acid without using any templates. The hollow microspheres were composed of α-Fe₂O₃ nanoparticles with the diameter range from 20 to 40 nm. The effects of reaction parameters such as reaction time, temperature, concentration of FeCl₃·6H₂O solution, and initial pH on the morphology of the final products were investigated. A possible formation mechanism of hollow α-Fe₂O₃ microspheres was also proposed, where the acetic acid played a role of etching in the formation of hollow structure.     

Endoscopic sphincterotomy and laparoscopic cholecystectomy in an infant with cholecysto-choledocholithiasis

Laparoscopic cholecystectomy (LC) and endoscopic sphincterotomy (EST) are widely accepted procedures for cholecysto-choledocholithiasis in adults. However, their use in infants has not been reported. An 8-month-old girl presented with high fever and obstructive jaundice. Ultrasound scan showed acute cholecystitis with stones in the bile duct. After 2-week-long antibiotic therapy the acute cholecystitis and hepatic impairment resolved. An endoscopic retrograde cholangiopancreatography (ERCP) confirmed choledocholithiasis and cholecystolithiasis. Risk factors for the development of biliary calculi were not detected. One month after the restoration of her liver function, she underwent EST using a side-viewing endoscope with a small sphincterotome. A common bile duct stone was extracted using a basket catheter. LC was then carried out. The time interval between the EST and LC was 34 days. No complications have been noted for 6 months.