Influence of drawing and heat treatment on surface free energies of polyethylene terephthalate fibers

The surface free energies of polyethylene terepthalate fibers with different draw ratios were experimentally determined by contact angle measurements inn-alkane/water systems. The dispersive component of the surface free energy increased with increasing draw ratio, whereas the nondispersive one remained almost constant. After heat treatment, the dispersive surface free energy increased, but was reduced above 140°C. The nondispersive component increased by heat treatment at 190°C. The increases in the density and birefringence of the fibres due to the drawing and heat treatment suggested that the increase in the dispersive surface free energy was caused by the increase in the atomic density at the fiber surface due to drawing and heat treatment. ESCA results indicated that the increment in the nondispersive surface free energy due to heat treatment was caused by the addition of functional groups to the fiber surface due to heat treatment.     

Preparation of water‐soluble pullulans bearing pendant C60 and their aqueous solubility

Water‐soluble fullerene‐bearing pullulans were successfully prepared by the addition reaction of azide‐substituted pullulans with fullerene C₆₀ . The chemical structure of the products was characterized by IR, UV, and NMR spectroscopy. It was found that the saturation solubility of the C₆₀ moiety strongly depends on the degree of substitution (DS) of the sample, indicating that an optimum DS value of the C₆₀ moiety exists for its aqueous solubility.     

Development of silicon nitride fiber from Si-containing polymer by radiation curing and its application

A silicon nitride fiber (Si₃N₄) was synthesized from polycarbosilane (PCS) fiber by radiation application. PCS fibers were cured by electron beam (EB) irradiation in a helium gas atmosphere prior to the pyrolysis. The cured PCS fiber was converted to Si₃N₄ ceramic fiber with flexibility by nitridation in ammonia gas at a high temperature of 500–1000°C. The obtained Si₃N₄ fibre showed a high heat resistance up to 1300°C, a high tensile strength of 2 GPa and excellent electrical resistivity of 10¹³ Ω cm. The ceramic fiber was fabricated to cloth and applied for electric wire insulator. The wire cable is flexible and can be applied at a high temperature atmosphere of around 1000°C.     

Simultaneous separation of common mono- and divalent cations on a zirconium-modified silica gel column by ion chromatography with non-suppressed conductimetric detection and tartaric acid–15-crown-5 as eluent

The application of laboratory-made zirconium-modified silica gels (Zr-silicas) as cation-exchange stationary phases to ion chromatography with conductimetric detection (IC–CD) for common mono- and divalent cations (Li⁺, Na⁺, NH₄⁺, K⁺, Mg²⁺ and Ca²⁺) was carried out. Zr-silicas were prepared by the reaction of the silanol group on the surface of silica gel with zirconium tetrabutoxide (Zr(OCH₂CH₂CH₂CH₃)₄) in ethanol. Zr-silica adsorbed on 10 mg zirconium g⁻¹ silica gel was a suitable cation-exchange stationary phase in IC–CD for the separation of these mono- and divalent cations. Excellent simultaneous separation and highly sensitive detection for these cations were achieved in 10 min by IC–CD using a Zr-silica column (150×4.6 mm I.D.) and 10 mM tartaric acid containing 10 mM 15-crown-5 (1,4,7,10,13-pentaoxacyclopentadecane) as the eluent. The proposed IC–CD method was successfully applied to the determination of major mono- and divalent cations in natural water samples.     

Biological stereoselective reduction of 3,3,5-trimethylcyclohexanone by Glomerella cingulata

The microbial transformation of 3,3,5-trimethylcyclohexanone was investigated using the plant pathogenic fungus, Glomerella cingulata. With this organism 3,3,5-trimethylcyclohexanone gave the corresponding cis- and trans-3,3,5-trimethylcyclohexanols with the ratio of 20:1 forming the cis-isomer highly stereoselectively, upon 5 days incubation together with 3,3,5-trimethyl-2-cyclohexen-1-one (isophrone) as a minor product.     

Dinuclear calcium complex with weakly NH...O hydrogen-bonded sulfonate ligands

The novel intramolecularly NH...O hydrogen-bonded Ca(II)-aryl sulfonate complex, [Ca2(SO3-2-t-BuCONHC6H4)2(H2O)4]n(2-t-BuCONHC6H4SO3)2n (1), sulfonate anion, (HNEt3)(SO3-2-t-BuCONHC6H4) (2a), (PPh4)(SO3-2-t-BuCONHC6H4) (2b), (n-Bu4N)(SO3-2-t-BuCONHC6H4) (2c), and sulfonic acid, 2-t-BuCONHC6H4SO3H (3), were synthesized. The structures of 1, 2a, and 2b depict the presence of the formation of NH...O hydrogen bonds between the amide NH and S-O oxygen for a series of compounds as determined by IR and 1H NMR analyses both in the solid state and in the solution state. Thus, the NH...O hydrogen bonds with neutral amide groups are available for investigation of the electronic state of the O- anion. The combined data from the IR and 1H NMR spectra indicate that the sulfonic acid, sulfonate anion, and Ca(II) complex have a substantially weak intramolecular NH...O hydrogen bond between the SO3 oxygen and amide NH. In the detailed comparison with the intense NH...O hydrogen bonds for the carboxylate, weak NH...O hydrogen bonds for sulfonate is due to the strong conjugation of the SO3- group with the lower nucleophilicity.     

Effects of electrolytes on the configuration change of cobalt(II)-halide complexes in chloroform/water reverse micelle systems.

The effects of various salts and HClO4 on the configuration change of cobalt(II)-halide complexes in CHCl3/CTAC or CTAB/H2O reverse micelle systems were examined at 25 degrees C by means of spectrophotometry, where CTAC and CTAB represent cetyltrimethylammonium chloride and bromide, respectively. The formation of the [CoCl4]> or [CoBr4]2- species of the tetrahedral configuration from [Co(H2O)6]2+ of the octahedral configuration in the reverse micelles was greatly promoted not only by a decrease in the W value (W = [H2O]/[surfactant]), but also, at a constant W value (e.g., W = 2.0), by the addition of relatively low concentrations of salts or the acid (e.g., 4.0 mol dm(-3) in the aqueous phase or 4.0 x 10(-2) mol dm(-3) in the whole reverse micelle system). The effects of perchlorate salts increased as Na+ < or = Li+ approximately H+ < Sr2+ < Ca2+ < Mg2+. Non-metallic salts, various tetraalkylammonium (R4N+) salts at lower concentrations, gave minor effects. The enhanced effects of metal salts on the configuration change of the cobalt(II)-halide complexes were interpreted by a further distortion of the hydrogen-bonded structure of the water in a "water pool" in the presence of salts of even relatively low concentrations. A conformation change with increasing temperature was also attributed to a further distortion of the water structure. An almost completed formation of [CoBr4]2- as well as [CoCl4]2- was attained in the reverse micelles at a low W value of 0.69 containing LiClO4 or HClO4. A partial transfer of the [CoX4]2- species from a "water pool" into the CHCl3 phase by the addition of the metal salts may be suspected. An examination of cobalt(II)-bromide complexes in dichloromethane/CTAB/H2O at W = 1.3 - 5.55 justified all the arguments concerning the chloroform systems. The Raman spectra of D2O containing concentrated LiBr and LiClO4 have supplied conclusive evidence that the hydrogen-bonded structure of the bulk water is completely distorted by extremely concentrated salts.     

Full automatic synthesis of [<Superscript>18</Superscript>F]THK-5351 for tau protein PET imaging in Alzheimer’s disease patients: 1 year experience

[¹⁸F]THK-5351, a new candidate for tau protein imaging, is based on an aryl quinoline structure. We report the full automatic synthesis using disposable cassettes under pH controlled [¹⁸F]fluorination. After the trapping of 88.5 ± 21.9 GBq of [¹⁸F]fluoride, it was eluted with potassium methansulfonate (KOMs) (pH 7.8)/K₂₂₂. After drying, 3 mg of the precursor was added to 1 mL DMSO and subjected to [¹⁸F]fluorination at 110 °C for 10 min. After hydrolysis, the final product was purified by HPLC. The overall radiochemical yield was 31.9 ± 11.1% (n = 22), satisfying all quality control criteria. It was stable for up to 6 h with high radiochemical purity as 99.8 ± 0.5%.     

Diatomic interactions in momentum space. The effect of polarization and floating functions

The method of momentum density for interatomic interactions is used to investigate the pictures and roles of the polarization and floating functions in momentum (p-) space. Referring to the previous results from the minimal LCAO (Finkelstein-Horowitz) momentum density, we quantitatively discuss the effect of these functions for the bonding process in the ground state of H ₂ ⁺ system. The essence of the polarization and floating effects is found to be a modulation of the oscillation in the two-center part of the momentum density. The polarization function introduces a term with a phase and the floating function enlarges the period of the oscillation. An increased migration of the density from the one-center to the two-center part is also important. As a result, both the functions contribute to emphasize the contraction and expansion of momentum density observed previously. However, the floating function disturbs the density distribution in high momentum region, reflecting the destruction of cusps in position (r-) space. We point out an error in the pioneer work of Duncanson.     

A study of embolizing materials for chemo-embolization therapy of hepatocellular carcinoma: embolic effect of cisplatin albumin microspheres using chitin and chitosan in dogs, and changes of cisplatin content in blood and tissue.

Hepatic artery of dogs was embolized with cisplatin (CDDP) albumin microspheres containing chitin and chitosan to investigate the in vivo CDDP release kinetics from CDDP albumin microspheres, the CDDP cumulative characteristics in the liver, and the influence of microsphere administration on hepatic tissue. Results showed that changes in blood CDDP content were dependent on CDDP albumin microsphere type and that release kinetics were better sustained when chitin was added to the microspheres or when the microspheres were treated with chitosan. In particular, the administration of CDDP in the chitin-containing CDDP chitosan albumin microspheres showed a blood CDDP content of approximately 0.26 micrograms Pt/ml 14 d after administration. The administration of chitin-containing or chitosan treated CDDP microspheres showed a CDDP content in the hepatic tissue of 0.14 to 0.23 micrograms Pt/g 28 d after administration. They also showed better control of CDDP release than those without chitin or chitosan treatment. No CDDP influence on hepatic tissue was observed. We conclude that, even in vivo, chitin and chitosan are effective embolic materials.