bluuebunny/crossref_metadata_2025 huggingface dataset:
Nonsteroid Immune Modulators and Bone Disease
Authors: TAMLER RONALD , EPSTEIN SOLOMON
Published: July 2006

Abstract: Glucocorticoids have been the main agents for preventing organ rejection,but unfortunately they possess serious side effects. Newer immunosuppressive agents have therefore been introduced to overcome these effects and have had a dramatic impact on reducing the incidence of organ rejection, enhancing donor organ acceptance, and hence patient survival posttransplantation. However, calcineurin inhibitors (CIs), such as cyclosporine and tacrolimus, also have serious effects causing rapid and severe bone loss in animal models and humans. The mechanism accounting for this action is unclear at present, but the role of T lymphocyte actionviaRANKL seems to be of essence in triggering bone loss. The mechanism is complex andin vitrostudies often produce results that are opposite to those seenin vivo.In addition to acute, rapid, and severe bone loss (ARSBL), the clinical picture shows an extremely high incidence of fractures at all sites, and depends upon the organ transplanted, preexisting bone disease, interval before transplantation, and the dose and duration of multiple immunosuppressive drugs. Other immune‐modifying drugs, such as azathioprine, mycophenolate mofetil, and sirolimus, which are used in conjunction with glucocorticoids and CIs have not been shown to promote bone loss experimentally or clinically. With the exception of glucocorticoids, all of the agents discussed here demand further investigation with regard to their effects on bone health in the clinical setting.
Bone Destruction in Multiple Myeloma
Authors: MATSUMOTO TOSHIO , ABE MASAHIRO
Published: July 2006

Abstract:  Multiple myeloma (MM) is characterized by accumulation of monoclonal plasma cells in the bone marrow and progression of lytic bone lesions. MM cells enhance bone resorption by triggering a coordinated increase in RANK ligand and decrease in osteoprotegerin in the bone marrow. Macrophage inflammatory protein (MIP)‐1α and (MIP)‐1β are secreted by MM cells, and play a major role in the enhancement of bone resorption by MM cells. Furthermore, the growth and survival of MM cells are enhanced by contact with osteoclasts (OCs) suggesting the presence of a vicious cycle between OCs and MM cells. OCs also enhance angiogenesis in concert with MM cells largely through the cooperative actions of osteopontin from OCs and VEGF from MM cells. The angiogenic effect may further facilitate the vicious cycle between bone destruction and MM cell expansion. In addition, MM cells secrete soluble factor(s) to suppress bone formation. Secreted Frizzled‐related protein (sFRP)‐2, an inhibitor of Wingless type (Wnt) binding to Frizzled, is produced by most MM cells, and immunodepletion of sFRP‐2 abrogates the inhibition of bone formation. Thus, MM cells enhance bone resorption and suppress bone formation to cause destructive bone lesions. Further elucidation of the mechanism of bone destruction by MM may lead to a novel therapeutic approach to prevent bone destruction and tumor growth.
Osteogenic Regulation of Vascular Calcification
Authors: TOWLER DWIGHT A. , SHAO JIAN‐SU , CHENG SU‐LI , PINGSTERHAUS JOYCE M. , LOEWY ARLEEN P.
Published: July 2006

Abstract:  Vascular calcification increasingly afflicts our aging and dysmetabolic population, predisposing patients to cardiovascular mortality and lower extremity amputation. Active osteogenic processes are evident in most histoanatomic variants, including elaboration of BMP2‐Msx2 signals required for craniofacial bone formation. We developed an animal model of diet‐induced diabetes, dyslipidemia, and vascular calcification. High‐fat diets promote vascular calcification in male low‐density lipoprotein receptor (LDLR)‐deficient mice, with concomitant upregulation of aortic BMP2 and Msx2 gene expression. We wished to test if Msx2 exerts pro‐calcific actions during vascular calcification, as it does in craniofacial bone. We studied CMV‐Msx2Tg+;LDLR+ transgenic mice (C57Bl/6), a model previously demonstrated to recapitulate features of Msx2 signaling during craniosynostosis. After 16 weeks of fatty diets, vascular calcification was studied in CMV‐Msx2Tg+ versus nontransgenic sibs. Only CMV‐Msx2Tg+ mice fed high‐fat diets exhibited vascular calcium accumulation by alizarin red staining, noted in the tunica media of coronary arteries and the aorta. Gene expression studies revealed that while Msx2 was expressed primarily in adventitial cells, alkaline phosphatase (ALP) expression and calcification occurred primarily in the tunica media. Msx2 promotes the elaboration of a pro‐osteogenic milieu by upregulating expression of Wingless type (Wnt) ligands while downregulating the canonical antagonist, Dickkopf (Dkk1). Msx2 upregulates aortic Wnt signaling in vivo, revealed by the analysis of TOPGAL+ (Wnt reporter) versus CMV‐Msx2Tg+; TOPGAL+ mice. Aortic Msx2 exerts pro‐osteogenic signaling in vivo and in vitro, mediated in part via the enhancement of paracrine Wnt signaling. Strategies that selectively inhibit aortic Msx2‐Wnt cascades may help diminish the initiation and progression of diabetic vascular disease.
Bisphosphonates
Authors: RUSSELL R. GRAHAM G.
Published: July 2006

Abstract: The discovery and development of the bisphosphonates (BPs) as a major class of drugs for the treatment of bone diseases has been a fascinating journey that is still not over. In clinical medicine, several BPs are established as the treatments of choice for various diseases of excessive bone resorption, including Paget's disease of bone, myeloma and bone metastases, and osteoporosis. Bisphosphonates are chemically stable analogues of inorganic pyrophosphate, and are resistant to breakdown by enzymatic hydrolysis. Bisphosphonates inhibit bone resorption by being selectively taken up and adsorbed to mineral surfaces in bone, where they interfere with the action of the bone‐resorbing osteoclasts. Bisphosphonates are internalized by osteoclasts and interfere with specific biochemical processes. Bisphosphonates can be classified into at least two groups with different molecular modes of action. The simpler non‐nitrogen‐containing bisphosphonates (such as clodronate and etidronate) can be metabolically incorporated into nonhydrolyzable analogues of adenosine triphosphate (ATP) that may inhibit ATP‐dependent intracellular enzymes. The more potent, nitrogen‐containing bisphosphonates (such as pamidronate, alendronate, risedronate, ibandronate, and zoledronate) are not metabolized in this way but can inhibit enzymes of the mevalonate pathway, thereby preventing the biosynthesis of isoprenoid compounds that are essential for the posttranslational modification of small GTP‐binding proteins (which are also GTPases) such as rab, rho, and rac. The inhibition of protein prenylation and the disruption of the function of these key regulatory proteins explain the loss of osteoclast activity and induction of apoptosis. The key target for bisphosphonates is farnesyl pyrophosphate synthase (FPPS) within osteoclasts, and the recently elucidated crystal structure of this enzyme reveals how BPs bind to and inhibit at the active site via their critical N atoms. In conclusion, bisphosphonates are now established as an important class of drugs for the treatment of many bone diseases, and their mode of action is being unraveled. As a result their full therapeutic potential is gradually being realized.
Mechanisms Involved in Skeletal Anabolic Therapies
Authors: MARTIN T.J. , QUINN J.M.W. , GILLESPIE M.T. , NG K.W. , KARSDAL M.A. , SIMS N.A.
Published: July 2006

Abstract:  Since parathyroid hormone (PTH) is the only proven anabolic therapy for bone, it becomes the benchmark by which new treatments will be evaluated. The anabolic effect of PTH is dependent upon intermittent administration, but when an elevated PTH level is maintained even for a few hours it initiates processes leading to new osteoclast formation, and the consequent resorption overrides the effects of activating genes that direct bone formation. Identification of PTH‐related protein (PTHrP) production by cells early in the osteoblast lineage, and its action through the PTH1R upon more mature osteoblastic cells, together with the observation that PTHrP± mice are osteoporotic, all raise the possibility that PTHrP is a crucial paracrine regulator of bone formation. The finding that concurrent treatment with bisphosphonates impairs the anabolic response to PTH, adds to other clues that osteoclast activity is necessary to complement the direct effect that PTH has in promoting differentiation of committed osteoblast precursors. This might involve the generation of a coupling factor from osteoclasts that are transiently activated by receptor activator of nuclear factor‐κB ligand (RANKL) in response to PTH.

New approaches to anabolic therapies may come from the discovery that an activating mutation in the LRP5 gene is responsible for an inherited high bone mass syndrome, and the fact that this can be recapitulated in transgenic mice, whereas inactivating mutations result in severe bone loss. This has focused attention on the Wnt/frizzled/β‐catenin pathway as being important in bone formation, and proof of the concept has been obtained in experimental models.
Misconceptions About Calcimimetics
Authors: NEMETH E.F.
Published: July 2006

Abstract:  Calcimimetics are ligands that activate the calcium receptor. Some are small molecules and of these, the most extensively studied are phenylalkylamines like cinacalcet. This compound is a positive allosteric modulator that selectively targets the parathyroid calcium receptor to inhibit the secretion of parathyroid hormone. Cinacalcet is the first calcimimetic compound to attain regulatory approval for the treatment of hyperparathyroidism resulting from end‐stage renal disease. The discovery of calcimimetics and the receptor they act on are considered with the intent of extracting lessons relevant to medical research and the discovery of new drugs.
Multiple Roles of Hoxc8 in Skeletal Development
Authors: JUAN ASTER H. , LEI HAIYAN , BHARGAVA PRERNA , LEBRUN MARIELLE , RUDDLE FRANK H.
Published: July 2006

Abstract:  We are interested in investigating the function of Hoxc8 in skeletogenesis during mouse development. Previous studies have shown that deregulation of Hoxc8 expression in the mouse leads to several skeletal defects, such as homeotic transformation in the thoracic vertebrae, abnormal development of the rib cage, and overproliferation of chondrocytes in the hypertrophic area.
By deleting a crucial enhancer of Hoxc8 in vivo, we found that precise temporal expression of Hoxc8 is important for determining the correct identity of the vertebral column in early embryos. We also identified downstream targets of Hoxc8 relevant to osteoblast differentiation at later developmental stages.
Restoration of Bone Mass in Hpg Mouse by Preoptic Area Grafting
Authors: RAJENDREN GOPALAN , ZHOU HANG , MOONGA BALJIT S. , ZAIDI MONE , SUN LI
Published: July 2006

Abstract:  Hereditary hypogonadism in the hpg mouse, caused by a deletion mutation in the gonadotropin‐releasing hormone (GnRH) gene, is associated with sterility, absent ovarian development, and undetectable circulating sex steroids. Eight‐month‐old female hpg mice had a significantly reduced bone mineral density (BMD) at the lumbar spine, femur, and tibia. In addition, the mice showed significant reductions in liver and kidney weight, with virtually nonexistent ovaries. Successfully transplanted hpg mice with preoptic area grafts contained GnRH‐positive neurons, consistent with our previous experience, and the host median eminence was innervated by GnRH immunoreactive fibers. A return of reproductive function was evident from increased ovarian weight and vaginal cornification. Of note was that grafted hpg mice showed a complete reversal to baseline of their BMD measured at all three sites. This establishes that the low bone mass that occurs in old hpg mice can be fully and rapidly ameliorated by preoptic area grafting.
Bone Remodeling in Health and Disease: Lessons From Mathematical Modeling
Authors: KOMAROVA SVETLANA V.
Published: July 2006

Abstract:  Parathyroid hormone is the single anabolic treatment for osteoporosis currently approved by U.S. Food and Drug Administration. The physiology underlying anabolic actions of parathyroid hormone remains mysterious, since only when applied intermittently, does it increase bone mass. This study employs mathematical modeling to consider multiple concomitant effects of parathyroid hormone and local regulators on bone turnover. Remarkably, due to coupling between osteoclasts and osteoblasts, anabolic effects of parathyroid hormone emerged from a single action—stimulation of osteoclastic bone resorption. This study provides a novel conceptual framework for the development of highly desirable anabolic treatments for bone diseases.
The Effect of Anti‐TNF‐α Therapy on Spinal Bone Mineral Density in Patients with Crohn's Disease
Authors: PAZIANAS MICHAEL , RHIM ANDREW D. , WEINBERG ANDREW M. , SU CHINYU , LICHTENSTEIN GARY R.
Published: July 2006

Abstract: Proinflammatory cytokines, including tumor necrosis factor‐α (TNF‐α) might be, at least partially, responsible for the development of osteopenia or osteoporosis in Crohn's disease. We investigated whether anti‐TNF therapy for Crohn's disease could have any skeletal impact. Therefore, we studied the effects of infliximab, a monoclonal antibody against TNF‐α with and without bisphosphonates, on spinal bone mineral density (BMD). The effect of corticosteroids was also analyzed. A retrospective cohort analysis was performed on 61 patients with Crohn's disease and low BMD by serial DXA scans. Twenty‐three patients were on infliximab and 36 patients were on bisphosphonates. Mean duration between DXA scans was 2.2 ± 0.99 years. After controlling for corticosteroid use, patients with concurrent infliximab and bisphosphonate treatment exhibited a greater increase in BMD compared to those on bisphosphonates alone (+6.7%/year vs. +4.46%/year,P= 0.045); corticosteroids inhibited this effect (P= 0.025). However, infliximab alone had no effects on BMD. Patients receiving bisphosphonates showed a significant increase in lumbar spine BMD compared to those not on bisphosphonates (+3.97% change in T score/year vs. −3.68%/year,P< 0.0001). Concurrent corticosteroid use significantly inhibited this effect (+2.15%/year vs. +4.97%/year,P= 0.0014). Concurrent infliximab use may confer an additional benefit to that already documented for bisphosphonate use alone; bisphosphonates are beneficial in the treatment of low BMD in patients with Crohn's disease, though corticosteroids may partially inhibit this effect.
Coordination Behavior of O2 and CO in a Solid Film Consisting of Hemoglobin and Maltose
Authors: Chung Joo Eun , Sakai Hiromi , Takeoka Shinji , Nishide Hiroyuki , Tsuchida Eishun
Published: July 2006

Solid hemoglobin (Hb) films were prepared by casting from a mixed solution of human hemoglobin and maltose (wt ratio of Hb/maltose is 60/40). The behavior of O2 and CO in coordinating to Hb in the films was then observed. The coordination equilibrium constants of both ligands were smaller by about an order of magnitude, and the rate constants (kon and koff) were smaller by about 13 orders of magnitude, than those of aqueous solutions of Hb. Interestingly, O2 and CO saturation was limited to 52% and 86%, respectively, under a partial pressure of 760 Torr (1 Torr = 133.322 Pa) of each gas, in spite of the one-to-one ligand binding ratio in aqueous solutions. This is due to the restraint of the structural change from a tense to a relaxed state in the solid phase. The limited saturation of the coordination in the solid phase was found to increase to 100% when a small amount (5.9%) of water was added; a significant structural change from the tense to the relaxed states followed.
Kinetics of the Peptide Formation Catalyzed by Thermolysin in a Homogeneous Aqueous–Organic System
Authors: Kunugi Shigeru , Suzuki Noriko , Sakamoto Akira , Yoshida Masumi
Published: July 2006

The effect of an organic solvent on the thermolysin-catalyzed peptide condensation reaction from acylamino acid and amino acid amide was investigated. Profiles of the apparent equilibrium yield were roughly divided into three regions: precipitation-driven (mostly low to medium organic-solvent concentration), clear and homogeneous (middle to rather high concentration), and inactivated conditions (very high (>80%) concentration).

In the second, homogeneous region (70%(v/v) DMSO), the kinetics of the condensation reaction were followed by taking into account the simultaneous, solvent-induced gradual inactivation of the enzyme. The dependence on the carboxyl component concentration gave apparent K′m and k′cat parameters for Cbz–Phe and Cbz–Trp; we found that even at 70% DMSO, thermolysin had similar rate parameters and activity to those in 10% DMSO [Wayne and Fruton, Proc. Natl. Acad. Sci. U.S.A., 80, 3241 (1983)]. The amine-component concentration dependence showed distinct substrate-inhibition profiles for both LeuNH2 and PheNH2.
Cyclic Fixed-Bed Operations over K2CO3-on-Carbon for the Recovery of Carbon Dioxide under Moist Conditions
Authors: Hirano Shinichi , Shigemoto Naoya , Yamada Shinichi , Hayashi Hiromu
Published: July 2006

A modified chemical-absorption method capable of cyclic fixed-bed operations under moist conditions for the recovery of carbon dioxide from flue gases has been proposed employing K2CO3-on-carbon. Deliquescent potassium carbonate was favorably supported on activated carbon as well as on bound carbon dioxide in the presence of water vapor by the following reaction:

After breakthrough, the entrapped carbon dioxide was released by the decomposition of hydrogencarbonate at a higher temperature above 150 °C to shift the reaction in reverse by steam, which could be condensed by cooling to afford high-purity carbon dioxide. An effective use of the pore space as microtanks for aqueous potassium carbonate was verified with XRD evidence under a very humid condition of 7.3% H2O, as anticipated. The amount of CO2 uptake was very small under a dry condition, but increased abruptly in the presence of moisture. Potassium carbonate on carbon was crystalline 2K2CO3·3H2O, even when in contact with moisture of 1.7% H2O; this revealed that it is not necessary for K2CO3 to be in the aqueous phase. Illustrative cyclic fixed-bed operations for the recovery of carbon dioxide under a condition close to the actual flue gas of 13.8% CO2 with 10% H2O at 100 °C under atmospheric pressure were demonstrated up to 10 cycles.
Effect of an Oxygen-Binding Reaction at the Cobalt Porphyrin Site Fixed in a Polymer Membrane on Facilitated Oxygen Transport
Authors: Suzuki Takayuki , Soejima Yuji , Nishide Hiroyuki , Tsuchida Eishun
Published: July 2006

Oxygen transport was facilitated in polymer membranes bonded with new derivatives of [meso-α,α,α,α-tetrakis(o-pivalamidophenyl)porphyrinato]cobalt (CoPs). The oxygen-binding reactivity of fixed CoPs strongly influenced the facilitated oxygen transport. CoP having a larger cavity structure showed a more rapid reactivity and achieved a higher oxygen permeability in the membrane. There existed correlations of the oxygen-binding and -dissociation rate constants with the diffusion constant of oxygen via CoPs fixed in the membrane.
Chemical Preparation of Polyaniline and Its Derivatives by Using Cerium(IV) Sulfate. Novel Preparation of Polyxylidines
Authors: Toshima Naoki , Yan Hu
Published: July 2006

Polyaniline and its derivatives were prepared by using the cerium(IV) sulfate as an oxidant instead of the conventional ammonium peroxodisulfate. The reaction conditions were optimized with emphasis on the conductivity and yield. The reaction of 3,5- and 2,3-dimethylaniline using cerium(IV) sulfate gave the corresponding polymers, respectively, although no polymeric products were obtained from these aniline derivatives using ammonium peroxodisulfate as an oxidant. The polyaniline and its derivatives were characteristic of the Emeraldine structure on the basis of the IR spectra. A partially belt-like morphology of the polyaniline, when prepared in an acidic medium, was observed by scanning electron microscopy. The polymerization mechanism by cerium(IV) ions is discussed on the basis of the change in the UV-vis spectra during the reaction.
Factors Determining the Adiabatic or the Diabatic Pathway of the Photoisomerization of Unsaturated Bonds
Authors: Tokumaru Katsumi , Arai Tatsuo
Published: July 2006

Ethylenes substituted with aromatic nuclei of low triplet excitation energies undergo cis → trans one-way isomerization in an adiabatic way in the triplet state with a quantum chain process. A new general concept is introduced to cover various types of isomerization in the triplet state: the conventional two-way mutual diabatic isomerization, the newly found one-way isomerization, and inefficient isomerization. This is extended to describe the isomerization in the singlet excited state which occurs in either a diabatic or an adiabatic pathway.
The Investigation of Conductivity of Liquid NdCl3–LiCl–KCl System by Mixture Design
Authors: Yifeng Zhang , Dianpeng Sui , Xuebing Huang , Shulan Wang
Published: July 2006

Scheffe’ simplex centroid design and alternating electric bridge method have been used to design an experiment and to measure the conductivity of the rare earth molten salt system NdCl3–LiCl–KCl. The results are presented in the form of a regression equation between composition and conductivity, as well as in the form of an isogram of conductivity for the ternary system.
Ionic Fragmentation of CF3Cl Photoexcited in the Cl L-Shell, C K-Shell, and F K-Shell Transition Regions
Authors: Suzuki Isao H , Saito Norio , Bozek John D
Published: July 2006

Fragment ions produced from CF3Cl have been measured in the soft X-ray region using monochromatized synchrotron radiation and a time-of-flight mass spectrometer. The yield ratios for ion production were determined from the TOF spectra over the energy range of 44 through 1200 eV, and the partial yield spectra for the individual ions were observed around the Cl L2,3-edges, the C K-edge, and the F K-edge. The atomic chlorine ion, Cl+, has the greatest intensity between 100 and 700 eV, and exhibits a steep increase at the Cl L2,3-edges. The yield ratios of F+ and C+ decrease sharply at the Cl L2,3-edges and greatly increase at the C K-edge and F K-edge. Some fragment ions, e. g. CF+, have distinctive yield changes upon excitation of the inner-shell electron to unoccupied molecular orbitals.
Characterization of Charge Transfer and Charge Transport in Polypyrrole Film Electrodes
Authors: Komura Teruhisa , Usui Takahiro , Takahasi Kousin
Published: July 2006

The a.c. response of polypyrrole film electrodes in 0.2 M KNO3 was investigated at different applied potentials and film thicknesses. The results of impedance analysis on the basis of the Randles equivalent circuit indicated that the electron exchange between a metal and the polymer controlled the rate of charge-transfer process at the film electrode. Accordingly, the oxidation of the polymer proceeds from the back of the film to its surface. The resistance due to electric migration in the film strongly depended on the concentration of the supporting electrolyte; this dependence suggests that the migration is ionic. This effect may be due to a change in the solvent swelling of the polymer. The oxidation of the polymer brought about each decrease in the charge-transfer resistance at a metal–polymer interface and the limiting resistance associated with the diffusion of charge carriers. The low-frequency pseudocapacitance of the polymer increased with increasing oxidation level and film thickness, which was expected from a finite diffusion model.
Spectrophotometric Determination of Nanogram Amounts of Tin after Extraction from Iodide Media
Authors: Nalini Swaminathan , Balasubramanian Natesan , Ramakrishna Tiruvesaloor V
Published: July 2006

A spectrophotometric method for the determination of trace amounts of tin is described. Tin was selectively extracted as SnI4 into benzene and stripped into water. The stripping was treated with bromine water and the resulting iodate was treated with iodide to liberate iodine. The iodine was extracted into benzene and equilibrated with iodate in the presence of excess chloride and acid to produce ICl2− which was reextracted into benzene as ionpair with rhodamine 6G. Measurement of the benzene extract at 535 nm permitted the determination of tin when present in the concentration range 4—200 ng. The molar absorption coefficient was found to be 1.54 × 106 dm3 mol−1 cm−1 and the color system is stable for 1 h. The relative standard deviation for ten determinations of 100 ng of tin was found to be 2.1%. The efficiency of the reaction sequence was found to be 96.2%. The method was found useful for the precise determination of tin in steel and alloy samples.
Orientation Effect of Side Chain Substituents in Aromatic Substitution. Induced Ortho Nitration
Authors: Strazzolini Paolo , Verardo Giancarlo , Gorassini Fausto , Giumanini Angelo G
Published: July 2006

The presence of a free carboxyl or ester function on the α-carbon of toluene induces the nitration of the phenyl ring in the ortho position at or above the statistical value (chaperon effect), when pure HNO3 is used in CH2Cl2 solution. This is at variance with the results of classical nitration in H2SO4, where p-nitration predominates by far and m-nitration occurs at a remarkable extent. The new finding is explained in terms of precomplex formation.
A Novel, Readily Accessible Lactosaminyl Donor: N-Trichloroethoxycarbonyl-hexa-O-benzoyl-β-d-lactosaminyl Fluoride
Authors: Kaji Eisuke , Lichtenthaler Frieder W , Osa Yumiko , Zen Shonosuke
Published: July 2006

A simple, preparatively satisfactory 10-step sequence is described for converting lactose into a novel, suitably blocked lactosaminyl donor: N-Trichloroethoxycarbonyl-β-d-lactosaminyl fluoride (5). The key intermediate in this conversion is the particularly well-accessible oxime of lactosulosyl bromide (52% for the 6 steps from lactose), which on α-glycosidation with p-methoxybenzyl alcohol, oxime reduction, N-protection by Troc chloride, and the anomeric fluorination yields 5 (37% for the 4 steps). The utility of 5 as an effective donor was proved by the β-selective glycosylation of the primary 6-OH of 1,2 : 3,4-di-O-isopropylidene-α-d-galactopyranose (14) and the 3-OH of methyl 2,4,6-tri-O-benzyl-β-d-galactopyranoside (16), both affording the respective trisaccharides 15 and 18 in high yields. The latter, when subjected to N-deprotection, N-acetylation, and de-O-acylation gave, in 42% yield based on donor 5, β-d-Gal-(1→4)-β-d-GlcNAc-(1→3)-β-d-Gal-(1→Me, a core trisaccharide unit of immunologically important carbohydrate antigens.
Catalytic Effect of Five-Coordinate Organotin Bromide or Tetraphenylstibonium Bromide on the Chemo- and Stereoselective Addition of Tin Enolate to α-Halo Ketone
Authors: Yasuda Makoto , Oh-hata Tatsuhiro , Shibata Ikuya , Baba Akio , Matsuda Haruo , Sonoda Noboru
Published: July 2006

Two types of catalysts, five-coordinate organotin bromides and tetraphenylstibonium bromide, similarly promoted the selective addition of tin enolates to the carbonyl moiety in α-halo ketones. The reaction with 2-chlorocyclohexanones and the enolates gave chlorohydrins bearing chloro- and hydroxyl groups in the cis-conformation. Chemoselective carbonyl addition to acyclic α-halo ketones was followed by effective cyclization to 2-(2-oxoethyl)oxiranes. The structural and bonding analogy of both catalysts may be responsible for the similar catalytic activities which induced the chemo- and stereoselective addition.
Syntheses and Structures of Novel Fused-Ring Systems Containing Six or Seven Sulfur Atoms: 2,3:5,6-Bis(ethylenedithio)thieno[3,2-b]thiophene and 3,4:6,7-Bis(ethylenedithio)thieno[3,2-c][1,2]dithiin
Authors: Tanaka Motoko , Ishida Takayuki , Nogami Takashi , Yoshikawa Hajime , Yasui Masanori , Iwasaki Fujiko
Published: July 2006

Novel fused-ring molecules, 2,3:5,6-bis(ethylenedithio)thieno[3,2-b]thiophene and 3,4:6,7-bis(ethylenedithio)thieno[3,2-c][1,2]dithiin, were synthesized for the development of new conducting organic salts. They have six and seven sulfur atoms, respectively. Their molecular and crystal structures were determined by X-ray crystallographic analyses. Their oxidation potentials were measured, compared with those of the related donor molecules, and analyzed by a molecular-orbital calculation.
Enzymatic Resolution of the Sterically Hindered myo-Inositol Derivative
Authors: Ling Lei , Ozaki Shoichiro
Published: July 2006

A modification of the enzymatic resolution has been developed for the resolution of the sterically hindered myo-inositol derivative. In this method, a side chain, which contains a terminal hydroxyl group on it, was introduced to a chiral hydroxyl group, and the terminal hydroxyl group on side chain was used for resolution. Enzymes could recognize the asymmetric center through the distal terminal hydroxyl group. Racemic 3,4,5,6-O-tetrabenzyl-myo-inositol was resolved by this method.
Intramolecular Hydrogen-Atom Transfer in 2-Alkylbenzoyloxyl Radicals as Studied by Transient Absorption Kinetics and Product Analyses on the Photodecomposition of Bis(2-alkylbenzoyl) Peroxides
Authors: Wang Jun , Tsuchiya Masahiro , Tokumaru Katsumi , Sakuragi Hirochika
Published: July 2006

The pulsed-laser excitation of bis(2-methylbenzoyl) peroxide at 308 nm in acetonitrile afforded a broad absorption band at 500—800 nm due to 2-methylbenzoyloxyl radicals. The decay of this band accompanied the growth of another band at 350 nm due to 2-carboxybenzyl radicals produced by an intramolecular hydrogen-atom transfer from the neighboring 2-methyl group; the rate constant was 1.7 × 107 s−1 at 23 °C, the activation energy and frequency factor being 17 kJ mol−1 and 1010.5 s−1, respectively. The rates for intramolecular hydrogen-atom transfer in 2-MeCH2C6H4CO2· and 2-PhCH2C6H4CO2· are much higher than that in 2-CH3C6H4CO2·, since the parent peroxides, (2-MeCH2C6H4CO2)2 and (2-PhCH2C6H4CO2)2, exhibited only 350-nm bands ascribable to the corresponding 2-carboxybenzyl radicals, even immediately after laser excitation.

The pulsed-laser photolyses of the above-mentioned peroxides afforded PhCH2R, 2-HOCOC6H4CH(R)CH2CN, and 2-HOCOC6H4CHRCHRC6H4CO2H-2 (R = H, Me, and Ph) as the main products in acetonitrile. The formation of PhCH2R is explained in terms of the contribution of two-bond fission of the O–O and C(α)–C bonds of the peroxide in the excited singlet state in competition with O–O bond cleavage followed by an intramolecular hydrogen-atom transfer.
Study of the Fatigue Process and the Yellowing of Polymeric Films Containing Spirooxazine Photochromic Compounds
Authors: Baillet Gilles , Giusti Gérard , Guglielmetti Robert
Published: July 2006

Photochromic polyurethane films containing 5-substituted 1,3-dihydro-3,3-dimethyl-1-alkylspiro[2H-indole-2,3′-[3H]pyrido[3,2-f][1,4]benzoxazine] and 1,3-dihydro-1,3,3-trimethylspiro[2H-indole-2,3′-[3H]naphth[2,1-b][1,4]oxazine] were degraded under xenon light exposure. The loss of the photochromic response was monitored by spectrophotometry as a function of the irradiation time; meanwhile, the photoproduct formation and the amount of photochromic material still available were analyzed by chromatography after liquid–solid extraction. At the same time, the fade rates were monitored after flash-excitation photolysis or after the photostationary state during degradation. It was clearly demonstrated that the loss of photochromism was due exclusively to a photooxidation process of the initial dye, and not to an acceleration of the bleaching or a potential screen effect caused by the photoproducts.
In-situ Kinetic Studies on Direct Fluorination of Thin Polyethylene Films with QCM
Authors: Hara Noriaki , Fukumoto Hisatoshi , Watanabe Masahiro
Published: July 2006

Fluorination of polyethylene (PE) films with fluorine gas was studied by using the quartz crystal microbalance technique from the interest for the preparation of wet-proofed carbon black with fluorinated polyethylene (FPE) film for application to gas-diffusion electrodes in fuel cells. The fluorination reaction proceeds clearly in three separated steps, i.e., the first transient step, the 2nd step controlled by the chemical reaction between F2 and PE molecules, and the 3rd step controlled by the diffusion rate of dissolved F2 in FPE. The complete fluorination of PE films of ca. 2—10 μm in thickness can be achieved after sufficient reaction time. It was found that the fluorination at the 2nd step obeys the first order kinetics regarding F2 concentration with the activation energy of only 34.3 kJ mol−1. The fluorination at the 3rd step proceeded linearly with the square-root of the reaction time. Diffusion parameters and apparent activation energies for the fluorination at the 3rd step were determined by solving Fick’s diffusion equation based on those experimental data. Both of them were very large in comparison with that for un-reacting gases, which were ascribed to the fluorination step proceeded by the reactive diffusion process.
Halofluorination of Alkenes Using Dilute Hydrofluoric Acid
Authors: Kuroboshi Manabu , Hiyama Tamejiro
Published: July 2006

Iodofluorination of alkenes was achieved with N-iodosuccinimide, potassium hydrogendifluoride, and 1 M hydrofluoric acid using tetrabutylammonium fluoride as a phase-transfer catalyst. The active fluorinating reagent was shown to be tetrabutylammonium dihydrogentrifluoride by preparing the salt in a different way and by effecting the same transformation under anhydrous conditions. Bromofluorination of alkenes also was carried out using 1,3-dibromo-5,5-dimethylhydantoin. Treatment of the I–F adducts with DBU afforded fluoro olefins stereospecifically.
The Quenching of Lumichrome Fluorescence by β-Cyclodextrin : Evidence for Inclusion Complex
Authors: Sarkar Biswajit , Das Utpal , Bhattacharyya Subirnath , Bose Swapan K
Published: July 2006

The formation of inclusion complex between lumichrome and β-cyclodextrin was studied by fluorimetric and solubility methods. The accessibility of lumichrome to the iodide ion in presence of β-cyclodextrin was also studied. The equilibrium constant of formation of this inclusion complex, K, determined by fluorometric method and solubility method is 966 and 491 mol dm−3, respectively.
Semiconductor Photocatalysis. ZnS-Nanocrystallite-Catalyzed Photooxidation of Organic Compounds
Authors: Yanagida Shozo , Kawakami Hiroshi , Midori Yoshihide , Kizumoto Hirotoshi , Pac Chongjin , Wada Yuji
Published: July 2006

Freshly prepared ZnS (nano-ZnS) suspensions catalyze photooxidation of organic substrates under band-gap irradiation with water as a good electron acceptor, while H2 evolves concomitantly. The organic substrates with hetero atoms or carbon–carbon double bonds (π-bonds), such as triethylamine (TEA), diethylamine (DEA), methanol, ethanol, cyclopentene, cyclohexene, 2-methylfuran, toluene, and ethylbenzene, undergo effective one-hole oxidation. This leads to efficient carbon–carbon bond forming reactions between cumulatively formed radicals at the α-carbon adjacent to the hetero atom or the π-bond. The photooxidation in the presence of a larger quantity of water results in successive oxidation of the intermediary α-carbon radicals, giving the two-hole oxidation products, e.g., DEA and acetaldehyde from TEA, and formaldehyde from methanol. The formation of the intermediary α-carbon radical has been clarified by ESR analysis using 2-propanol as an organic substrate. Semi-empirical molecular orbital calculations suggest that the nano-ZnS-catalyzed photooxidation should be predictable from energetics in the formation of the α-carbon radicals through one-hole oxidation and deprotonation, and from change in the bond order of αC–H bond of the α-carbon cation radicals.
Kinetics of Oxygen Exchange between Arsenic Acid and Solvent Water
Authors: Okumura Akiko , Matsumiya Yuko , Yamamoto Kasumi , Ueno Reiko , Suzuki Mariko , Yamabe Shinichi
Published: July 2006

The rates (R) of the oxygen exchange of arsenic acid with solvent water were measured over a wide range of hydrogen-ion concentrations. At pH > 4, a 18O tracer method was used ([As(V)] = 0.07 mol dm−3, 0—50 °C). At pH < 5, 17O NMR line broadening technique was used ([As(V)] = 1 mol dm−3, 50—90 °C). Over the whole pH range studied, the variation of R amounts to 1010, and the comprehensive rate law is expressed as: R = k11h[H+][H3AsO4] + k11[H3AsO4] + k12[H2AsO4−] + k13[HAsO42−] + k14[AsO43−] + k21[H3AsO4]2 + k22[H3AsO4][H2AsO4−] + k23[H2AsO4−]2 + k24[H2AsO4−][HAsO42−] + k25[HAsO42−]2. The rate constant for each elementary process in the equation was obtained. The activation parameters of each elementary process were evaluated. The oxygen exchange rate of arsenic acid was compared with that of phosphoric acid. The contrast of an SN2-type exchange of the former acid vs. an SN1-type one of the latter is suggested.
Effect of Sonolysis on Acid Degradation of Chitin to Form Oligosaccharides
Authors: Takahashi Yasuko , Miki Fumie , Nagase Kazuko
Published: July 2006

Chitin [partially deacetylated β-(1→4)-linked 2-acetamide-2-deoxy-β-d-glucopyranose, (GlcNAc)n] was hydrolyzed by hydrochloric acid under the ultrasound irradiation. The first seven members of (GlcNAc)n in the degradation fluid were analyzed with high performance liquid chromatography (HPLC). The produced amounts of (GlcNAc)1—7 obtained by the degradation in concd HCl increased almost in proportion to the degradation time up to 120 min when sonolysis was used concomitantly. The yield of saccharides in the degradation fluid by concd HCl with sonolysis was about 2—4 times as much as that in the hydrolysis without sonolysis. The yield(%) increased with increasing of the concentration of HCl (6—12 mol dm−3) but decreased with increase of the concentration of chitin, showing a solvent volume effect. For the production of higher oligosaccharides, such as (GlcNAc)5—7, degradation with sonolysis for not longer than two hours is desirable. Deacetylated products were negligible. The effect of sonolysis is discussed from the aspect of the interactions of water with saccharide chains.
Molecular Reorientation in AlBr3·NH3, as Studied by the 81Br Nuclear Quadrupole Resonance
Authors: Ishihara Hideta , Yamada Koji , Okuda Tsutomu , Weiss Alarich
Published: July 2006

The temperature dependence of the 81Br nuclear quadrupole resonance (NQR) frequencies and spin-lattice relaxation times (T1Q) of 81Br NQR have been measured in aluminum tribromide–ammonia (1/1), AlBr3·NH3, crystals. The 81Br NQR spectrum consists of 6 lines, which are ascribed to two AlBr3 groups. This has been confirmed by the observation of 27Al NQR using the 81Br ↔ 27Al spin echo double resonance method. A 81Br T1Q measurement revealed that the activation energies for the reorientation of the AlBr3 groups or the molecular tumbling of AlBr3·NH3 are 61.1 and 81.6 kJ mol−1. The difference in the activation energies was reflected in the temperatures of the fade-out of the 81Br NQR lines at Tf = 320 and 350 K, respectively.
N,N-Dimethylformamide + 2-Methoxyethanol Binary Mixtures. Viscosity and Activation Energy of Viscous Flow at Various Temperatures
Authors: Corradini Fulvio , Franchini GianCarlo , Marchetti Andrea , Tagliazucchi Mara , Tassi Lorenzo
Published: July 2006

Dynamic viscosity (η) of binary solvent mixtures of N,N-dimethylformamide (DMF, component 1) + 2-methoxyethanol (ME, component 2) has been investigated at 19 temperatures ranging from −10 to +80 °C. Some empirical equations have been applied in order to establish the best regression fitting procedures η = η(T), η = η(X1) and η = η(T, X1). For this binary solvent system, the viscometric properties are continuous but not linear functions of the mixture composition. Therefore, experimental η values were used to calculate the excess viscosities (ηE) and excess Gibbs activation energies (ΔG*E) of viscous flow. Both these quantities strongly deviate from ideality over the whole composition range of the investigated mixtures. Furthermore, deviations from the ideal behaviour could be very useful in order to evidentiate the formation of solvent–cosolvent complex species and to evaluate their stoichiometrical composition.
Formation of the Oxanickelacyclopentene Complex from Nickel(0), Carbon Dioxide, and Alkyne. An ab initio MO/SD-CI Study. Part II. Reactivity and Regioselectivity of Hydroxyacetylene
Authors: Sakaki Shigeyoshi , Mine Kazuya , Hamada Taisuke , Arai Toru
Published: July 2006

The formation reaction of oxanickelacyclopentene from [Ni(PH3)], hydroxyacetylene (a model of ethoxyacetylene), and carbon dioxide was investigated by the ab initio MO/SD-CI method. Of the two possible products of oxanickelacyclopentene and , the former was yielded with a lower activation energy (Ea) of 27 kcal mol−1 and a higher exothermicity (Eexo) of 31 kcal mol−1 than the latter (Ea = 38 kcal mol−1 and Eexo = 25 kcal mol−1). This result is consistent with the regioselectivity experimentally observed in the Ni(0)-catalyzed 2-pyrone synthesis from ethoxyacetylene and carbon dioxide. The regioselectivity of this reaction and the reactivity of hydroxyacetylene are discussed in terms of the energy level and the shape of the hydroxyacetylene π* orbital.
Kinetics of Electrochemical Reduction of Carbon Dioxide on a Gold Electrode in Phosphate Buffer Solutions
Authors: Noda Hidetomo , Ikeda Shoichiro , Yamamoto Akio , Einaga Hisahiko , Ito Kaname
Published: July 2006

The kinetics of the CO formation by electrochemical reduction of carbon dioxide on a gold electrode investigated in a series of potassium phosphate buffer solutions. CO is the principal product under the above condition. Small amounts of hydrocarbons, such as CH4, C2H4, and C2H6, are detected in the solutions of pH 5.2, 6.2, and 6.8. The Tafel slopes of the partial current density for the CO formation, ICO, at different pH are all ca. −120 mV/decade. The reaction mechanism has been proposed on the basis of the relationships between ICO and the electrode potential and between ICO and the reaction order with respect to CO2, which is ca. 1.
IR Investigation of Selective Reduction of NO by Ethene on Cu-ZSM-5
Authors: Tabata Takeshi , Ohtsuka Hirofumi , Kokitsu Mikako , Okada Osamu
Published: July 2006

Adsorbed species during the reaction of selective catalytic reduction of NOx by hydrocarbons (HC-SCR) on Cu ion-exchanged ZSM-5 (Cu-ZSM-5) were investigated by in situ FT-IR using isotopes as well as gas phase analysis. No oxygen-containing species was observed by IR and no reaction proceeded in the presence of gaseous O2 and C2H4 below 473 K, at which HC-SCR occurs. However, an extra NOx species (tentatively assigned to organic nitrite or nitrate species), other than inorganic NOx species derived from O2 and NO, appeared very rapidly in IR at 1670 cm−1 at room temperature, in the presence of adsorbed NO2 species, gaseous C2H4 and NO. Afterwards, a carbonyl species (1677 cm−1) was formed gradually at room temperature. When the extra NOx species was observed, N2 and N2O evolved even at room temperature, therefore, the extra NOx species is considered to be related to HC-SCR. In the O2 + C2H4 + NO reaction at 473 K, no nitrogen-containing species, except for quite a small amount of nitrile (2168 cm−1), was observed in IR. At 473 K, N2, and CO evolved very rapidly with a steep increase in the IR intensity of carboxylate (1574 and 1375 cm−1), while CO2 and carbonyl species increased more slowly.
Segmented Contractions of Gaussian Basis Sets for Relativistic Molecular Calculations
Authors: Watanabe Yoshihiro , Matsuoka Osamu
Published: July 2006

A method for segmented contractions of relativistic Gaussian basis sets is proposed, in which the large- and the small-component coefficients of the contracted basis sets are taken directly from the uncontracted relativistic basis sets and their kinetic balance is disregarded. The energy increases by this contraction scheme are found to be very small and the variational collapse does not occur. This method also reproduces very well the orbital energies and the radial expectation values of uncontracted basis sets. Examples of calculations on iodine (Z = 53), gold (Z = 79), and thorium (Z = 90) are reported in detail.
Micro Enzyme-Sensor with an Osmium Complex and Porous Carbon for Measuring Galactose
Authors: Miyata Kazuhisa , Fujiwara Masahiko , Motonaka Junko , Moriga Toshihiro , Nakabayashi Ichiro
Published: July 2006

A micro enzyme-sensor, based on galactose oxidase (EC 1.2.3.9) and a tris(2,2′-bipyridine) complex of osmium(II/III) as a redox mediator ([Os(bpy)3]2+/3+), fabricated on a carbon electrode (25 μm diameter), was developed for measuring galactose. To obtain the carbon electrode, a platinum-disk electrode (25 μm diameter) was etched in hot aqua regia to create a cavity (depth of ca. 3—5 μm) at its tip. A porous carbon material was prepared from 90% acetylene black and 10% Teflon emulsion as a binder, and then packed into the cavity of the platinum-disk electrode’s tip. The carbon electrode was immersed in the osmium complex with 0.1 mol dm−3 LiClO4 in order to adsorb it in the carbon pores, which was monitored based on an increase in the anodic peak current and the cathodic peak current based on the osmium complex redox potential by the cyclic voltammogram. The tip of the carbon electrode was dipped overnight in a buffer solution of pH 7.00 containing galactose oxidase so as to immobilize it on this surface by adsorption. The characteristics of the porous-carbon material surface by X-ray diffraction (XRD) and scanning electron microscopy (SEM), the calibration curve for measuring of galactose, and the effects of the pH, temperature and concomitant compounds were investigated. By the XRD measurement, the porous carbon after treating a Zonyl FSN fluoro-carbon surfactant solution, a 5% Nafion® solution with methanol, and an osmium complex with 0.1 mol dm−3 LiClO4 showed good crystallinity compared with carbon powder. The structure of the carbon-electrode surface was visually confirmed using SEM photographs. The carbon surface had many pores, and galactose oxidase existed on it after adsorption. Under the optimum conditions the amperometric response of this sensor was linear over concentration ranges of 0.01—5.00 mmol dm−3 galactose; the correlation coefficient was 0.999.
Synergistic Extraction of Rare Earths(III) with β-Diketone and Nitrogen-Containing Terdentate Ligand, 2,2′:6′,2″-Terpyridine
Authors: Satake Saeko , Tsukahara Satoshi , Suzuki Nobuo
Published: July 2006

The synergistic extraction of rare earth(III) ions (RE: La, Sm, Tb, and Lu) was investigated using a β-diketone (HA), i.e., trifluoroacetylacetone (Htfa) or hexafluoroacetylacetone (Hhfa), in the presence of a terdentate ligand, 2,2′:6′,2″-terpyridine (terpy) into benzene. The formation of complexes such as RE(A)2+ or RE(A)2+ in the aqueous phase was observed. The synergistic enhancement is attributed to the formation of an adduct RE(A)3terpy in the benzene phase. The adduct formation constants (βS,1) and the synergistic extraction constants were determined. For each RE(III), the βS,1 value in the Htfa–terpy system is smaller than that in the Hhfa–terpy system. The βS,1 values decrease with increasing atomic number of RE(III) in the Htfa–terpy system, but the βS,1 value for La(III) is smaller than that for the other RE(III) in the Hhfa–terpy system.
Mössbauer Emission Spectra of 119Sn in Binary Compounds of Antimony and Tellurium
Authors: Ambe Shizuko , Ambe Fumitoshi
Published: July 2006

The Mössbauer emission spectra of defect 119Sn atoms arising from 119Sb and 119mTe were measured in GaSb, InSb, In2Te3, ZnSb, CdSb, CdTe, and Ag2Te. The lattice sites of defect 119Sn atoms in these binary compounds were determined on the basis of the obtained Mössbauer parameters and the recoil energy associated with EC decays of the source nuclides. Together with the results of previous studies, the isomer shifts of both defect and normal 119Sn were shown to correlate with the electronegativitity of ligands in binary compounds of the main-group elements, such as Sn, Sb, and Te.