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PurposeDistraction osteogenesis (DO) is commonly performed for mandibular reconstruction during the growth period. We tested the hypothesis that parathyroid hormone-related protein (PTHrP) in mandibular condylar cartilage and underlying trabecular bone in growing individuals undergo changes in response to distraction forces.Materials and methodsForty-eight 6-week-old male Sprague-Dawley rats were used. Animals underwent unilateral mandibular distraction using a distractor that we devised, and unoperated animals were evaluated as controls. DO procedure was performed: 3 days' latency period, 0.4 mm/day rate, total 4.0 mm. Changes in cartilage morphology, PTHrP activity, and 3-dimensional trabecular bone structure changes measured by micro-computed tomography were examined at 0, 2, 4, and 6 weeks of consolidation.ResultsA marked irregularity was noted in the superior portion of the distracted side's condylar cartilage that resolved after distraction ceased. PTHrP was more strongly expressed in the hypertrophic layer of condylar cartilage on the distracted side than in controls, up to 6 weeks after the end of distraction. Subchondral trabecular bone volume, percent bone volume, and trabecular number in the superior and posterior regions of the condyle decreased significantly by 2 weeks after distraction. These parameters returned to normal in the posterior condyle, but not in the superior part of the condyle by 6 weeks following distraction.ConclusionThese results suggest that unilateral mandibular distraction in growing rats causes temporary morphologic alterations of trabecular bone structure on the distracted side accompanied by increased production of PTHrP in the mandibular condyle.

A fast, inexpensive, and highly efficient synthesis of aromatic polyamide dendrimers, without the need for protection and deprotection steps, has been developed. Dendrons and various types of polyamide dendrimers were easily prepared by a convergent approach involving activation of a carboxylic acid at the focal point using a small excess of thionyl chloride as the activating agent, followed by condensation with an unprotected AB2 building block, 3,5-bis(4-aminophenoxy)benzoic acid. A third generation dendrimer with a molecular weight of 8197 Da was prepared in a high yield, using 1,3,5-tris[N-(4-aminophenyl)]benzenetricarboxamide as a core molecule. A dendrimer with a carboxylic acid group at its core (molecular weight:  10 700 Da) could be prepared from the third generation dendron with 3,5-bis(3,5-diaminobenzoylamino)benzoic acid as the core molecule. All the above products purified only by precipitation revealed a high purity, assessed using matrix assisted laser desorption ionization time-of-flight mass spectroscopy spectra.

A photosensitive semi-alicyclic poly(benzoxazole) based on poly(o-hydroxy amide) containing adamantyl units (PAHA) and 1,3,5-tris[(2-vinyloxy)ethoxy]benzene (TVEB) as an acidolytic de-cross-linker and a photoacid generator, diphenyliodonium 9,10-dimethoxyanthracene-2-sufonate (DIAS), has been developed. PAHA with a weight-average molecular weight of 24 100 was prepared from 1,3-adamantanedicarbonyl chloride (ADC) and 4,4‘-(hexafluoroisopropylidene)bis(o-aminophenol) (6FAP) in the presence of lithium chloride in N-methylpyrrolidinone (NMP) at 0 °C for 12 h. By thermal treatment, PAHA was easily converted to semi-alicyclic poly(benzoxazole) (PABO) that was insoluble in organic solvents and showed high thermal stability (Td5 = 520 °C under N2). The UV−vis spectra of PAHA and PABO indicated excellent transparency at wavelengths above 320 and 400 nm, respectively. The average refractive index of PABO was 1.523, and the dielectric constant estimated from the refractive index was 2.55 at 1 MHz. This value is significantly lower than those of conventional wholly aromatic PBOs. The photosensitive PABO precursor, PAHA containing 15 wt % TVEB and 5 wt % DIAS, showed a sensitivity of 40 mJ/cm² and a contrast of 4.0 when it was exposed to a 365 nm light (i-line) and developed with a 2.38 wt % aqueous tetramethylammonium hydroxide solution (TMAHaq) at 25 °C. A fine positive image of 10 μm line-and-space pattern was also printed in a film which was exposed to 70 mJ/cm² of i-line by contact-printing mode. The positive image in PAHA was converted to the positive image in the PABO film by the thermal treatment without pattern deformation.

A novel thermally stable and low dielectric poly(binaphthylene ether) (2) has been developed. Polymer 2 was easily prepared by oxidative coupling polymerization of 2,2‘-bis(1-naphthyloxy)-1,1‘-binaphthyl (1) with FeCl3 as an oxidant. This polymerization produced regiocontrolled polymer 2 with a number-average molecular weight of 14 000 Da and a molecular weight distribution of 3.3. The 5% weight loss and glass transition temperatures of polymer 2 were 520 and 301 °C, respectively. The dielectric constant of polymer 2 at 1 MHz was directly measured from the capacitance as 2.50. The modulus and hardness of polymer 2 were determined as 9.8 and 0.42 GPa.

A novel hole-transporting poly[di(1-naphthyl)-4-tolylamine:DNTA] (PDNTA) has been developed. PDNTA was easily prepared by oxidative coupling polymerization of DNTA using FeCl3 as an oxidant. This polymerization produced regiocontrolled PDNTA with high molecular weights. PDNTA exhibited strong UV−vis absorption bands at 267 and 370 nm in chloroform solution. Their photoluminescence spectra showed a maximum peak band around 445−448 nm in the blue region. The organic light-emitting device (OLED) prepared by spin-casting PDNTA solution onto ITO-coated glass substrate in conjunction with Alq and LiF/Al, as an electron-transporting light-emissive layer and a metal cathode, respectively, showed a maximum luminescence of 25 000 cd/m² at 12.5 V.

Ordered poly(amide−thioether) (17) was prepared by tandem type polymerization of 2,4-dichlorophenyl acrylate (11), 4,4‘-thiobis(benznenthiol) (12), and 4,4‘-oxydianiline (16). The polymerization was carried out by mixing all monomers in the presence of catalytic amounts of triethylamine (TEA) and 1-hydroxybenzotriazole (HOBt) in 1-methyl-2-pyrrolidinone (NMP) at 20 °C for 2 h and then 80 °C for 2 days, yielding polymer 17 with a number-average molecular weight (Mn) of 25 000. Authentic ordered poly(amide−thioether) (18) was prepared to verify the structure of polymer 17. The microstructure of polymers obtained was investigated by ¹H and ¹³C NMR spectroscopy, and it has been found the polymer obtained has the expected ordered structure. Furthermore, model reactions were studied in detail to demonstrate the feasibility of ordered polymer formation.

The reaction of HCl gas with hydrogrossular [Ca3Al2(SiO4)0.8(OH)8.8] was performed using a fixed-bed flow-type reactor above 400 °C. It was found that, upon heating, the hydrogrossular was dehydrated to mayenite phases [Ca12Al10Si4O32(OH)6 and Ca12Al10Si4O35], which reacted with the HCl gas in the temperature range of 400−950 °C to finally produce wadalite (Ca12Al10Si4O32Cl6) and CaCl2. Thus, HCl gas could be efficiently removed from effluent gases above 400 °C. The amount of chlorine fixed per gram of wadalite and CaCl2 was 0.22 g. An apparent activation energy of 24.2 kJ/mol was obtained for the reaction between HCl and hydrogrossular, which was consistent with the values found in the literature for the reaction between HCl and CaO, i.e., 20.9, 22.8, or 28.1 kJ/mol.

A new positive working photosensitive alicyclic polyimide precursor based on poly(amic acid tert-butyldimethylsilylester) (3) and 2,3,4-tris[2-diazo-1-(2H)-naphthalenone-4-sulfonyloxy]benzophenone (D4SB) as a photosensitive compound has been developed. Polymer 3 was prepared by ring-opening polyaddition of bicyclo[2.2.1]heptane-2-methanecarboxylic-3,5,6-tricarboxylic-2,3:5,6-dianhydride (2) with 5-tert-butyldimethylsilylamino-N-tert-butyldimethylsilyl-1,3,3-trimethylcyclohexanemethylamine (1) in toluene/N,N-dimethyl acetamide (DMAc) (2/1 weight ratio) at 20 °C for 3 h. The film of polymer 3 showed excellent transparency at the wavelengths above 250 nm. The dissolution behavior of polymer 3 containing 30 wt % D4SB after exposure was studied, and it was found that the difference of dissolution rate between the exposed and unexposed areas was enough to obtain a high contrast due to the photochemical reaction of D4SB in the polymer film. The photosensitive polyimide precursor containing 30 wt % D4SB showed a sensitivity of 60 mJ/cm² and a contrast of 1.7 when it was exposed to 365-nm light and developed with a 2.38 wt % aqueous tetramethylammonium hydroxide solution at 25 °C. A fine positive image of 10-μm-line and space patterns was also printed in a film which was exposed to 300 mJ/cm² by contact mode. The positive image in polymer 3 was converted to the positive image in the polyimide (PI) film by thermal treatment. The optically estimated dielectric constants of the polyimides with and without D4SB are 2.45 and 2.44, respectively. These values are significantly lower than those of conventional aromatic polyimides.

A new synthetic method to give wholly alicyclic polyimides with high molecular weights has been developed. The polymerization of cyclobutanetetracarboxylic dianhydride (1a) or bicyclo[2.2.1]heptane-2-methanecarboxylic-3,5,6-tricarboxylic-2,3:5,6-dianhydride (1b) with various N-silylated alicyclic diamines (2) was carried out in N,N-dimethylacetamide (DMAc) at room temperature, giving poly(amic acid trialkylsilylester)s (3) as precursor polymers that were hydrolyzed to poly(amic acid)s (4) with inherent viscosities up to 0.99 dL/g. Both polyimide precursors were readily converted to corresponding polyimides (5) by thermal treatment. These polyimides are readily soluble in polar aprotic solvents such as 1-methyl-2-pyrrolidone, N,N-dimethylacetamide and dimethyl sulfoxide at room temperature, and showed high thermal stability (Td10 = 420−445 °C in N2) and excellent transparency at wavelengths above 250 nm. The average refractive index of the polyimide 5aa was 1.498, and the dielectric constant estimated from the refractive index was 2.47.

Three- and four-armed star-shaped poly(ε-caprolactone)s were synthesized from trimethylolpropane and pentaerythritol as initiators using fumaric acid as an activator of the monomer, respectively. Star-shaped poly(ε-caprolactone)s could be satisfactorily obtained, which was confirmed by size exclusion chromatography equipped with low-angle laser light scattering and viscometer detectors. Comparing the melting points among the polymers with similar molecular weights, the order was as follows:  linear poly(ε-caprolactone) > three-armed poly(ε-caprolactone) > four-armed poly(ε-caprolactone). On the other hand, poly(ε-caprolactone)s with similar arm length showed similar melting points irrespective of the arm numbers. Thermal decomposition temperature of poly(ε-caprolactone)s increased with the arm number.

A convenient synthesis of aliphatic polyesters by the distannoxane-catalyzed polycondensation of aliphatic dicarboxylic acids and aliphatic diols in solvents under azeotropic conditions was developed. To determine the optimum conditions for polycondensation of succinic acid with 1,4-butandiol, the effect of various types of catalyst and their concentration was investigated. By choosing the appropriate solvent, the polymerization was made to proceed in a two-phase system of solvent and molten polymer, and in the presence of 0.001 mol % of 1-chloro-3-hydroxy-1,1,3,3-tetrabutyldistannoxane (CHTD), poly(butylene succinate) (PBS) with a weight-average molecular weight of 277 000 was obtained. This method was then successfully applied to the synthesis of various aliphatic polyesters, such as poly(ethylene succinate), poly(1,4-cyclohexanedimethylene succinate), and poly(ethylene sebacate).

The reaction between hydrogrossular and hydrogen chloride (HCl) gas was performed in a fixed bed reactor above 400 °C. The hydrogrossular was efficiently reacted with HCl gas in the temperature range of 400 to 950 °C and transformed into Ca12Al9.9Si4.05O32Cl5.9 (calcium aluminum chlorosilicate). The crystal structure of the product phase Ca12Al9.9Si4.05O32Cl5.9 was cubic, space group I%@mt;sys@%%@ob@%4%@obx@%%@mx@% 3d, with unit cell a = 12.0173(1) Å, and was similar to that of wadalite. The structure consists of a framework of (Al,Si)O4 tetrahedra. A large cavity in the framework accommodates Ca−Cl−Ca linearly coordinated atoms.

Poly(styrene-co-methacrylonitrile)s were polymerized in solutions with different polarities (n-hexane and THF) by low-temperature γ-ray irradiation polymerization in a temperature range of −83.6–30 °C. It was found by IR measurement that the composition of the copolymers changed remarkably due to the effects of the polarity of solvents and the polymerization temperature. The thermal degradation behavior in the flash pyrolysis and in the continuous heating pyrolysis of these copolymers was measured by Py-GC and controlled rate thermogravimetry (CRTG). The effects of the copolymer composition and sequence distribution on the thermal degradation behavior were investigated. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 3569–3577, 2000

Ca(2+)-sensitive tyrosine kinase Pyk2 was shown to be involved in angiotensin (Ang) II-mediated activation of extracellular signal-regulated kinase (ERK) via transactivation of epidermal growth factor receptor (EGF-R). In this study, we tested the involvement of Pyk2 and EGF-R in Ang II-induced activation of JNK and c-Jun in cardiac fibroblasts. Ang II markedly stimulated JNK activities, which were abolished by genistein and intracellular Ca(2+) chelators but partially by protein kinase C depletion. Inhibition of EGF-R did not affect Pyk2 and JNK activation by Ang II. Stable transfection with a dominant negative (DN) mutant for Pyk2 (PKM) completely blocked JNK activation by Ang II. DN mutants of Rac1 (DN-Rac1) and MEK kinase (DN-MEKK1) also abolished it, whereas those of Cdc42, RhoA, and Ha-Ras had no effect. Induction of c-Jun gene transcription by Ang II was abolished in PKM, DN-Rac1, and DN-MEKK1, in which Ang II-induced binding of ATF2/c-Jun heterodimer to the activator protein-1 sequence at -190 played a key role. These results suggest that 1) in cardiac fibroblasts activation of JNK and c-Jun by Ang II is initiated by Pyk2-dependent signalings but not by downstream signals of EGF-R or Ras, 2) Rac1 but not Cdc42 is required for JNK activation by Ang II upstream of MEKK1, and 3) ATF-2/c-Jun binding to the activator protein-1 sequence at -190 plays a key role for induction of c-Jun gene by Ang II.

Activated monomer cationic ring-opening polymerization of ε-caprolactone (ε-CL) and δ-valerolactone (δ-VL) and the synthesis of di- and triblock copolymers of a seven-membered cyclic carbonate (7CC) and these lactones initiated with n-butyl alcohol/HCl·Et2O and H2O/HCl·Et2O were carried out to obtain the corresponding homopolymers and block copolymers with narrow polydispersity ratios in one pot quantitatively. The molecular weights of the obtained polymers could be controlled with the feed ratio of the monomer and initiator.