bluuebunny/crossref_metadata_2025 huggingface dataset:
Fluorometric Determination of Amino Acids and Proteins Utilizing a Copper(II) Catalyzed Reaction
Authors: Mori Hisakazu , Sakai Kazue , Yamashina Kyoko , Hirata Sayuri , Horie Kumiko
Published: July 2006

Amino acids accelerated the copper(II)-catalyzed oxidation of di-2-pyridyl ketone hydrazone (DPKH) to form a fluorescent compound. With the use of this enhancement effect of catalysis, various amino acids (l-histidine, l-cysteine, l-glutamic acid, glycine, Dl-serine, and l-arginine) could be determined by flow injection analysis. The detection limit of L-histidine was less than 2 pmol. On the contrary, proteins decreased the catalysis. Proteins were also determined through the utilization of this effect. In this determination, the addition of citric acid was found to be very effective. The detection limit of bovine serum albumin was less than 20 ng. The effect of protein upon the catalysis of copper(II) was considered to be ascribable to an inhibition of the coordination of DPKH to copper(II).
Ligand-Mediated Pseudohypersensitivity of Some 4f–4f Transitions in Neodymium(III) Interaction with Fluorinated Nucleic Acid Components
Authors: Misra Sudhindra N , Mehta Surendra B
Published: July 2006

Absorption difference and comparative absorption spectrophotometry of the systems containing Nd(III) and fluorinated nucleic bases (fluoroadenine, fluorocytosine, fluorothymine, and fluorouracil) and fluorinated nucleosides (fluoroadenosine, fluorocytidine, fluorothymidine, and fluorouridine) in ethyl acetate–water (90:10), have shown that certain 4f–4f transitions (4I9⁄2→4G7⁄2, 4F7⁄2, 4F5⁄2, and 4F3⁄2), which are generally considered to be insensitive, have been found to exhibit substantial sensitivity towards even minor changes in the coordination environment around neodymium(III). The observation has been referred to as “Ligand-Mediated Pseudohypersensitivity.” The magnitude of various spectral parameters (energy interaction, Slater-Condon interelectronic repulsion Fk, spin–orbit interaction ξ4f, nephelauxetic \barβ, b, δ, and Judd–Ofelt Tλ intensity and oscillator strength (P)), computed using regression analysis, has been used in exploring the degree of inner and outer sphere coordination, incidence of covalency and extent of involvement of metal 4f orbitals in bonding. The isolation of solid complexes and their characterization by elemental analysis, infrared spectral, and Karl Fischer titration suggested octa and nona coordinated environment around neodymium and some probable structures for these complexes have been proposed.
Photoinduced Nucleophilic Addition of Ammonia and Alkylamines to Aryl-Substituted Alkenes in the Presence of p-Dicyanobenzene
Authors: Yamashita Toshiaki , Shiomori Koichiro , Yasuda Masahide , Shima Kensuke
Published: July 2006

The photoamination of 1,1-diphenylpropene (1a) with ammonia and some primary alkylamines in the presence of p-dicyanobenzene gave the corresponding N-substituted 2-amino-1,1-diphenylpropane (2a–e) along with the formation of 3-methyl-4,4-diphenylbutanenitrile (3a), 1,1-diphenylpropane (4a), 3,3-diphenylpropene (5), and diphenylmethane (6). In the case of 1,1-diphenylethene (1b), N-substituted 1-amino-2,2-diphenylethane (2f–h), 4,4-diphenylbutanenitrile (3b), and 1,1-diphenylethane (4b) were produced. In photoamination with t-butylamine in acetonitrile, 3a and 3b were mainly formed as a consequence of the incorporation of acetonitrile to 1a and 1b. The photoamination of 1-phenyl-3,4-dihydronaphthalene (1c) with isopropylamine or t-butylamine gave cis- and trans-N-substituted 1-phenyl-2-amino-1,2,3,4-tetrahydronaphthalenes (15 and 16) in a ratio of ca. 8:2. The mechanism of photoamination is discussed in terms of a photochemical electron transfer of 1 to p-dicyanobenzene followed by a nucleophilic addition of the amine to the cation radical of 1.
On the Splittings of J-Aggregate Band in Pseudoisocyanine
Authors: Ito Hirotoshi , Agatsuma Masaru , I’Haya Y J
Published: July 2006

The observation of J-band splittings in the Fano–DeVoe type calculations of pseudoisocyanine aggregates is reported. Based upon the monoclinic structure of pseudoisocyanine iodide crystal, we build four models which respectively assume the lattice constants of the crystal structure. The one-dimensional (1D-) single polymer model is selected along a particular direction from the crystal structure. As we diminish the lattice constants uniformly, the 1D-single-polymer model comes to reproduce single J-bands, while two kinds of 2D-two-inter-polymer interaction models resolve the single J-bands into doublet through multiplet structures for the corresponding parameters. The 3D-four-inter-polymer interaction model brings about doubly split J-bands, but the shortening of the parameters resolves the doublet J-bands into quartet through multiplet structures. However, a single J-band is obtained by the assumption of an orthorhombic 3D-four-inter-polymer model which has the same parameters as those of the monoclinic iodide crystal except for the angle. The shapes calculated are found to be extremely sensitive to the geometrical values as well as the monomer spectroscopic parameters. The cause of the J-band splittings is ascribable to the excitonic interactions between at least two column polymers.
The Energy Aspect of Oil/Water Partition and Its Application to the Analysis of Quantitative Structure-Activity Relationships. Aliphatic Alcohols in the Liposome/Water Partition System
Authors: Fujiwara Hideaki , Da Yong-Zhong , Ito Katsuhiko , Takagi Tatsuya , Nishioka Yukako
Published: July 2006

The energy aspect of oil/water partition has been examined for several solutes in different partition systems by determining the thermodynamic parameters of the partition. The thermodynamic parameters changed systematically, depending on the polarity of the nonaqueous phase of the partition. To further investigate the partition system dependency of the QSAR (quantitative structure–activity relationships) treatments the thermodynamic properties have been determined for various aliphatic alcohols in a liposome/water system; the results are discussed with regard to the previous ones obtained in a 1-octanol/water system, while paying special attention to applicability in the QSAR analysis. The following trends were observed in common with the two partition systems of liposome/water and 1-octanol/water: 1. The enthalpy term (ΔHp°) can well reproduce the toxicity data for halogenated and nonhalogenated alcohols collectively, whereas the conventional logP (partition coefficient) term can be applied only for the two types of alcohols separately; 2. The entropy term (ΔSp°) adds a discernible contribution to the refinement of the regression analysis. A distinctive characteristic is also discussed from a statistical method of analysis for the thermodynamic properties obtained in the two partition systems.
Novel Transformation of Formyl Groups into Hydroxyl Groups Utilizing Deformylative Autoxidation of Aldehydes
Authors: Kigoshi Hideo , Imamura Yoshifumi , Sawada Akihiko , Niwa Haruki , Yamada Kiyoyuki
Published: July 2006

Structural requirements that cause deformylative autoxidation of aliphatic aldehydes are investigated. Decarbonylation of acyl radicals proceeds smoothly when the alkyl radicals that are formed can be stabilized by allylic conjugation. Further conjugation of the double bond in the allyl radical with a carbonyl or a cyclopropyl group allows position-selective peroxidation of the alkyl radical.
Fixation of Carbon Dioxide with Diphenylcarbodiimide as a Model of Biotin Enzyme Active Site and a Weak Base: The Carboxylation of Fluorene under Mild Conditions
Authors: Chiba Koji , Tagaya Hideyuki , Karasu Masa , Ono Tsuyoyuki , Saito Masaru , Ashikagaya Atsushi
Published: July 2006

Carbon dioxide was directly fixed into fluorene in the presence of diphenylcarbodiimide (DPC) as a model of a biotin enzyme active site and potassium hydrogencarbonate. It was considered that not only carbon dioxide but also the hydrogencarbonate ion were the carbon source in the presence of DPC. Weak bases such as potassium acetate, potassium propionate, and potassium formate were also effective for carboxylation.
Synthesis of Substituted Pyridines by a Cycloaddition Route Using Nitrile Oxides and Homoallyl Alcohols
Authors: Kanemasa Shuji , Asai Yoshihiko , Tanaka Junji
Published: July 2006

Cycloadditions of nitrile oxides with unprotected homoallyl alcohols, followed by Swern oxidations, lead to 5-(2-oxoalkyl)-2-isoxazolines. Subsequent Raney Ni reduction of the resulting heterocycles in ethanol in the presence of excess tetrafluoroboric acid affords substituted pyridine derivatives.
Association Characteristics of Amphiphilic α-Helices Connected by Flexible Links
Authors: Morii Hisayuki , Honda Shinya , Ichimura Kunihiro , Uedaira Hatsuho
Published: July 2006

Amphiphilic helical peptides interlinked with sequences bearing a flexible mobility were designed and synthesized. The sequences containing glycine and/or cystine were adopted for the linkage parts. The secondary structure of the peptides was investigated by circular dichroism(CD) and the super-secondary structure was estimated. The CD spectra and their pH dependence show that the peptides have almost the same α-helix contents as designed and that the helices associate to be “coiled-coil” at neutral pH. The apparent helix contents increase at low pH and some of helices are subject to denaturation at high pH. The denaturation of α-helix bundles by guanidine hydrochloride is contemplated to be three-state transition. It is proposed that the peptides construct α-helix bundles with both loose and tight contacts between helices. Two kinds of folded structure constructed with 2 or more helices are also suggested.
Metal Complexes of Peptides. V. Cobalt(III) Complexes with N-β-Alanyl-(S)-aspartate
Authors: Ama Tomoharu , Maki Ritsuko , Kawaguchi Hiroshi , Yasui Takaji
Published: July 2006

Three cobalt(III) complexes containing N-β-alanyl-(S)-aspartic acid (H3L), [Co(L)(en)] (en: ethylenediamine), [Co(L)(dien)] (dien: diethylenetriamine), and [Co(HL)(dien)]+, were newly prepared and characterized on the basis of their 13CNMR, UV-visible absorption, and circular dichroism spectra. The dipeptide L functions as a quadridentate ligand in [Co(L)(en)] and as terdentate ligands in [Co(L)(dien)] and [Co(HL)(dien)]+. The structures of these complexes are discussed in connection with those of [Co((S)-asp)(dien)]+(H2(S)-asp: (S)-aspartic acid) and [Co(edma)(dien)]2+ (Hedma: ethylenediamine-N-acetic acid).
Association of Symmetrical p-Dihalobenzenes with Cyclodextrins in Aqueous Medium
Authors: Takuma Tatsuyoshi , Deguchi Toshio , Sanemasa Isao
Published: July 2006

The complex formation of cyclodextrin (CyD, host) with symmetrical p-difluoro-, dichloro-, dibromo-, and diiodobenzenes (guests) has been studied in aqueous medium at 25°C by making use of the volatilization rate of guest molecules from the aqueous into gaseous phase. In the excess of the host, α- and β-CyDs form 1 : 1 and 2 : 1 (host : guest) complexes, while γ-CyD forms 1 : 1 complexes. The association constants, especially for α-and β-CyDs, increased with an increase in the size of the halogen atom. A linear relationship between the logarithm of the 1 : 1 association constant and the total surface area of guest molecule was found for CyD–monohalobenzenes and CyD–p-dihalobenzenes. The van der Waals force seems to be the main factor in stabilizing the associated complexes. The validity of the concept of microscopic binding constant is discussed.
Studies on Ferrocene Derivatives. VII. Solvent Effect on the Oxidation Reaction of t-Butylferrocenes
Authors: Hayashi Takatoshi , Okada Yutaka , Yamashita Tetsurou
Published: July 2006

The oxidation reactivity of t-butylferrocenes with air was measured in 1,2-dichloroethane or 1,4-dioxane. Their reactivity in 1,2-dichloroethane was increased with increasing the number of the substituents. It was considered that the oxidation proceeds through air oxidation with catalytic proton. On the other hand, in 1,4-dioxane, the conversion amount to oxidized form of ferrocene or t-butylferrocene suddenly incresed in the course of the reaction. In this solvent, the ferrocene nucleus was decomposed to give Fe3+ ion. It seems that the substrate was oxidized by Fe3+ ion formed.
Phosphorylation of Nucleotides with Inorganic Cyclo-Triphosphate
Authors: Tsuhako Mitsutomo , Kunitomi Rumi , Baba Yoshinobu , Miyajima Tohru
Published: July 2006

Phosphorylation of nucleotides (nucleoside 3′- and 5′-monophosphates, and 2′-deoxynucleoside 5′-monophosphates) with inorganic sodium cyclo-triphosphate (P3m) was studied in aqueous solutions under various conditions (mixing ratio of P3m to nucleotides, pH, reaction temperature, and time). (I) Unprotected nucleoside 5′-monophosphates (5′-NMP’s) were easily phosphorylated at the cis-2′,3′-diol by P3m to form selectively nucleoside 2′,5′-bis(monophosphate) (2′,5′-NDP’s), nucleoside 3′,5′-bis(monophosphate) (3′,5′-NDP’s), and nucleoside 2′,3′-cyclic 5′-bis(monophosphate) (cNDP’s). (2) The phosphorylation of 5′-NMP’s was strongly dependent on mixing ratio, pH, reaction temperature, and time. Under conditions of high mixing ratios of P3m to 5′-NMP’s (5:1–10:1), high pH (12), and room temperature, 92–98% of 5′-NMP’s was converted into 3′,5′-NDP’s and 2′,5′-NDP’s in roughly equimolar quantities. (3) Small quantities (5–8%) of cNDP’s were formed at the initial stage of reaction of 5′-NMP’s with P3m but in the course of the reaction for a long period, cNDP’s were hydrolyzed to 2′,5′-NDP’s and 3′,5′-NDP’s. (4) Nucleoside 3′-monophosphates (3′-NMP’s) and 2′-deoxynucleoside 5′-monophosphates (dNMP’s) could not be phosphorylated by P3m, which indicates that the presence of hydroxyl groups at both 2′- and 3′-positions on nucleotides is indispensable for the phosphorylation of nucleotides with P3m. (5) The mechanism of the formation of 2′,5′-NDP’s, 3′,5′-NDP’s, and cNDP’s in the phosphorylation of 5′-NMP’s with P3m is discussed.
Reaction of 1,2-Dichloroethane with Pyridine Using the 1R,4S,8R,11S-Tetramethyl-1,4,8,11-tetraazacyclotetradecanenickel(II) Cation as a Probe
Authors: Iwamoto Etsuro , Yokoyama Takashi , Nishimoto Jun , Yamashita Tamao , Kumamaru Takahiro
Published: July 2006

A spectral change of the title square planar cation [Ni(tmc)]2+ by an axial ligation of the halide ions in nitrobenzene was applied to kinetic studies of pyridine and alkyl halides. The ligation of the chloride ions proceeds with a formation constant of more than 1×104 dm3 mol−1 and rapidly with a rate of less than millisecond. It was found that 1,2-dichloroethane and dichloromethane react with pyridine through the Menschutkin reaction with a rate constant of 1.2×10−8 and 3.7×10−9 dm3 mol−1 s−1 at 35°C, respectively.
The Hypervirial Condition upon Coulson–Longuet–Higgins Polarizabilities in the Hückel Model
Authors: Isihara Makoto
Published: July 2006

This paper describes a fundamental condition upon Coulson–Longuet–Higgins polarizabilities in the Hückel model. The condition, named the hypervirial condition upon polarizabilities, consists of linear equations to be fulfilled by polarizabilities, being derivable from the hypervirial condition upon site electron densities and bond orders. The hypervirial condition upon polarizabilities can lead us to various simple relationships between polarizabilities, aided by the two auxiliary conditions stemming from the conservation of the number of electrons and from the Hellmann–Feynman theorem. The relationships, being characteristic of a system, will be useful for considering the reactivity of the system within the Hückel model. Several examples for typical systems are given to illustrate how the hypervirial and the auxiliary conditions work practically.
Mechanism of 2-Propanol Dehydrogenation with Suspended Nikel Fine-Particle Catalyst
Authors: Yamashita Masaru , Dai Feng-Yuen , Suzuki Minoru , Saito Yasukazu
Published: July 2006

Selective dehydrogenation of 2-propanol was performed with a suspended nickel fine-particle catalyst at high activity under refluxing conditions. The isotope effects, kH⁄kD for (CH3)2CDOH and (CD3)2CDOD were found to be 2.56 and 2.69, respectively, in contrast to 1.68 for (CH3)2CHOD, suggesting that the C–H bond dissociation at the methine position is rate-determining. With regard to (CH3)2CHOD and (CH3)2CDOH, a distinct difference was observed for the deuterium distributions among the liquid-phase components after the reaction, since deuterium transfer from the hydroxyl to the methyl and other groups proceeded tremendously for (CH3)2CHOD, whereas the methine group of (CH3)2CDOH changed little, even after a 5-h reaction under refluxing conditions. This contrast was well accounted for by the difficult splitting of the methine C–H bond and the facile dissociation of the hydroxyl group, in addition to a gradual H–D exchange due to the keto–enol equilibriation of the adsorbed acetone and the hydrogen transfer from 2-propanol to acetone. Distributions of H2, HD, and D2 were interpreted as well, which varied with the reaction periods and the kinds of substrates. Based on the proposed mechanism, strategies for a catalyst improvement suitable for a newly-proposed chemical heat pump system are discussed.
Nitriles in Heterocyclic Synthesis. Synthesis and Reactions of Pyrano[3,2-h]quinoline Derivatives
Authors: Khalil Z H , Abdel-Hafez A A , Geies A A , Kamal El-Dean A M
Published: July 2006

8-Quinolinol reacts with cinnamonitrile derivatives in presence of a basic catalyst to afford pyrano[3,2-h]quinolines (3a–f). The reaction of 3a with reagents such as acetic anhydride/pyridine, formamide, formic acid/formamide, and carbon disulfide gave the fused heterotetracyclic systems pyrimido[4′,5′: 6,5]pyrano[3,2-h]quinolines.
Synthesis of 2-(Trimethylsilyl)ethyl Benzenesulfenate and Benzeneselenenate and Their Reaction with Some Electrophiles in the Presence of Tetrabutylammonium Fluoride
Authors: Oida Tatsuo , Ohnishi Atsushi , Shimamaki Toshiharu , Hayashi Yoshiyuki , Tanimoto Shigeo
Published: July 2006

2-(Trimethylsilyl)ethyl benzenesulfenate was allowed to react with several halides in the presence of tetrabutylammonium fluoride (TBAF) to afford the corresponding phenyl sulfoxides as the main product. In the reaction of 2-(trimethylsilyl)ethyl benzeneselenenate and several halides with TBAF, the corresponding alcohols were obtained as the main product.
On the Mechanism of the Cleavage Reaction of (Methylthio)methyl Ether with Triphenylmethyl Cation
Authors: Niwa Haruki , Miyachi Yasuyoshi
Published: July 2006

The cleavage reaction of a (methylthio)methyl (MTM) ether with triphenylmethyl cation was not initiated by the previously proposed hydride abstraction with triphenylmethyl cation but promoted by the coordination of triphenylmethyl cation as a Lewis acid to the sulfur atom in the MTM group.
Preparation of Pyrazoles Using Hydrazyl Radicals Initiated by DPPH
Authors: Yoshihara Nobutoshi , Hasegawa Tadashi , Hasegawa Sadao
Published: July 2006

Hydrazyl radicals, initiated by DPPH, reacted with α,β-unsaturated ketones without any good leaving group on their β-positions to yield pyrazoles regio-selectively.
Catalytic Activity of Bismuth(III) Chloride for Dehydrochlorination of Poly(vinyl chloride)
Authors: Uemichi Yoshio , Takuma Kazuhiko , Sugioka Masatoshi , Kanazuka Takaji
Published: July 2006

Bismuth(III) chloride was found to be highly active as a catalyst for the dehydrochlorination of poly(vinyl chloride). The degree of dehydrochlorination was 97% at the highest. The catalyst showed high activity even in water vapor.
Sorption of Anionic Surfactants with Wood Charcoal
Authors: Fujita Itsusei , Tomooka Jyo , Sugimura Tsugiharu
Published: July 2006

The possibility of wood charcoal as an adsorbent, not as an energy source as in the past, was confirmed by the use of an anionic surfactant as the model adsorbate, and a trial sorption of polluting substances in an actual river by a wood charcoal column was conducted.
Studies on 4-Thiazolidinones. IX, The Conversion of 5-Substituted 2-Thioxo-4-thiazolidinones into Corresponding 2,4-Thiazolidinediones
Authors: Omar Mohamed T , Fouli Abd-Elrehiem , El-Garhi Mahmoud Z
Published: July 2006

The thioxo to oxo conversion in a variety of 2-thioxo-4-thiazolidinones 1 and 2 has been achieved simply by treating with bromine. A postulate for the route of interconversion is given and structures of all products are evidenced by analytical and spectral data.
Strong van der Waals Interactions in Water. Molecular Complexes of Porphyrins and Quinones in Organic and Aqueous Media
Authors: Kano Koji , Hayakawa Tadashi , Hashimoto Shizunobu
Published: July 2006

The stability of the molecular complexes between 5,10,15,20-tetraarylporphyrins and quinones in organic solvents has been compared with that in water. 5,10,15,20-Tetrakis(mono-substituted phenyl)porphines (RTPPs) hardly form molecular complexes with p-benzoquinone (BQ), 2,3,5,6-tetramethyl-p-benzoquinone (DQ), and 2,3,5,6-tetrachloro-p-benzoquinone (CQ) in dichloromethane (K>60 mol−1 dm3). In contrast, the stability constants (K<60 mol−1 dm3) for the molecular complexes of cationic porphyrins (TMPyP and TAPP) with BQ in water are much larger than those in methanol. The thermodynamic parameters clearly indicate that complexation in water is an enthalpically favorable process, suggesting that the van der Waals interactions are the main binding forces and that hydrophobic interaction does not play an important role in complex formation in water. The larger stability of the molecular complexes in water can be interpreted in terms of the nature of water, as demonstrated by Smithrud and Diederich (D. B. Smithrud and F. Diederich, J. Am. Chem. Soc., 112, 339 (1990)). The microscopically hydrophobic porphyrin ring many hardly be hydrated and interact with BQ through the van der Waals interactions without an extensive dehydration process. The water molecules bound to BQ should be released upon complexation, and the released water molecules may be incorporated tightly into the hydrogen-bonding networks of water. Such complexation in water seems to be an enthalpically favorable process.
Thermally Irreversible Photochromic Systems. Reversible Photocyclization of Non-Symmetric Diarylethene Derivatives
Authors: Nakayama Yasuhide , Hayashi Koichiro , Irie Masahiro
Published: July 2006

Non-symmetric diarylethenes with an indole ring on one end and a thiophene, a benzo[b]thiophene, or a pyrrole ring on the other end of the double bond were synthesized in an attempt to get thermally irreversible photochromic compounds having absorption bands at longer wavelengths. 2-(1,2-Dimethyl-3-indolyl)-3-(2,4,5-trimethyl-3-thienyl)maleic anhydride(8a) underwent photoinduced cyclization/ring-opening reactions with relatively high quantum yields (cyclization quantum yield: 0.15; ring-opening quantum yield: 0.40), and the both isomers were thermally stable. The closed-ring form had the absorption maximum at 595 nm with the edge extending to 760 nm. Cyclization/ring-opening reactions of 8a and 2-(1,2-dimethyl-3-indolyl)-3-(2-methyl-3-benzo[b]thienyl)maleic anhydride (9a) were induced by Ar ion (488 nm) and He–Ne (633 nm) lasers.
Resonance Raman Active Vibrations of Rubredoxin. Normal Coordinate Analysis of a 423-Atom Model
Authors: Saito Hiroshi , Imai Takeo , Wakita Kaori , Urushiyama Akio , Yagi Tatsuhiko
Published: July 2006

Normal coordinate analyses were performed on three molecular models of the rubredoxin of Desulfovibrio vulgaris, Desulfovibrio gigas, and Clostridium pasteurianum. The total 1081, 1093, and 1148 internal coordinates were specified by the X-ray analyzed coordinates of the 390, 399, and 423 atoms, respectively, in a mass-group approximation. The appropriately assumed values of Urey–Bradley force constants as well as some diagonal values of out-of-plane bending and torsional forces gave 146, 146, and 148 normal modes, respectively, in 250–450 cm−1 region. These are the deformational vibrations within the peptide skeleton of the protein molecules. The Fe–S stretching displacements of the FeS4 core contribute to a limited number of these vibrations. The modes having a totally symmetric Fe–S stretching contribution confined within a frequency region of 290–330 cm−1 in which the principal resonance Raman band of rubredoxin has been reported, and the several minor resonance Raman bands reported in the higher frequency region of 330–420 cm−1 were assigned to noraml modes having a non-totally symmetric Fe–S stretching character. The PED values indicated that all of these modes are constructed mostly by the deformational displacements in the peptide skeleton widely spread into the molecule around the FeS4 core. This feature is very similar to the case of the blue-copper protein studied previously.
Synthesis of 3,4′-Diaryl- and 4,4′-Diaryl-2,2′-bithienyls from 2,5-Dichlorothiophene
Authors: Sone Tyo , Umetsu Yasuhiro , Sato Kazuaki
Published: July 2006

3,4′-Diaryl-, and 4,4′-diaryl-2,2′-bithienyls, new classes of mixed thiophene–arene oligomers, were synthesized from 2,5-dichlorothiophene via 4-aryl-2-chlorothiophene in three and two steps, respectively. Namely, a Friedel–Crafts type self-condensation of 4-aryl-2-chlorothiophene, followed by catalytic dechlorination, yielded unsymmetrical bithienyls. Homocoupling of 4-aryl-2-chlorothiophene using a nickel–phosphine catalyst gave symmetrical bithienyls.
The Synthesis and Properties of Cyclohepta[a]phenalene-6,10-, -6,12-, -7,10-, and -7,12-diones and Their Dicationic and Dianionic Species
Authors: Kuroda Shigeyasu , Kanbata Yoshinobu , Fukuyama Yuriko , Hirooka Syuzi , Takeda Hideya , Tsuchida Tomohiko , Furuki Yoko , Sumi Takayuki , Hanida Osamu , Yamada Masaki , Shimao Ichiro
Published: July 2006

The titled new non linear non benzenoid quinone compounds of cyclohepta[a]phenalene-6,10-, -6,12-, -7,10-, and -7,12-diones have been synthesized. The dicationic species formed from quinones by protonation in a strong acid were revealed as diatropic compounds instead of a 16-pi electron system by an examination of spectral measurements, such as the 1H NMR and UV spectra. The stability of these quinones, dicationic species, and dianonic species electrically derived from quinones depends upon the positions of carbonyl groups with both steric and electronic factors.
Differential Thermal Analysis of Polyacrylonitrile in the Presence of Chlorine-Containing Polymers
Authors: Okamoto Masao , Saito Ken-ichiro , Motoishi Sadayuki
Published: July 2006

A differential thermal analysis (DTA) of polymer blends of polyacrylonitrile (PAN) with poly (α-chloroacrylonitrile) (PCAN) and poly (vinyl chloride) (PVC), prepared by coprecipitation from a solution containing both polymers, was carried out under nitrogen. Even if a small amount of PCAN or PVC was added to PAN, the exotherm peak position due to violent polymerization of the cyano groups, which appears at ca. 260°C in pure PAN, shifts to the higher-temperature side by ca. 40°C and its intensity becomes lower. Moreover, a new generation of heat is observed above ca. 220°C and ca. 260°C in the case of PAN–PCAN and PAN–PVC, respectively. These results were associated with the HCl generated during the heating process, since the chlorine atom formed by the reaction of a thermally degraded PAN polymer radical with HCl can both initiate polymerization of the cyano groups in PAN and terminate progress in polymerization by combination. Namely, DTA behavior could be explained by the effect of initiation (in the case of PAN–PCAN) and termination (in the case of PAN–PVC) upon the polymerization of cyano groups both below and above the temperature, respectively, at which PAN begins to be subjected to a sharp transition.
Cluster-ion Ejection from IR-preheated Liquid Water through Ion Pair Created by OH Vibrational Excitation
Authors: Toyama Namiki , Kohno Jun-ya , Kondow Tamotsu
Published: July 2006

Ions, OH−(H2O)n, were found to be ejected from a liquid beam of water under irradiation of Mid- and Near-IR lasers resonant to the fundamental and the fourth harmonic (vOH = 4) of the OH-stretching mode of liquid water, respectively. Dependence of the ion intensity on a delay time between the two lasers reveals that locally preheated water by the Mid-IR laser helps ejecting OH−(H2O)n to a vacuum through an ion pair (H+···OH−) created by the Near-IR laser.
Overview of Oral Modified-Release Opioid Products for the Management of Chronic Pain
Authors: Amabile Celene M , Bowman Bill J
Published: July 2006

Objective:

TO evaluate pharmaceutical and pharmacotherapeutic differences in oral opioid modified-release products used in the management of chronic pain.

Data Sources:

Searches of MEDLINE (1966–May 2006) and an extensive review of peer reviewed journals were conducted using the key search terms opioid, morphine, hydromorphone, and oxycodone. Supplemental information was gathered through the American Pain Society, and limited but relevant information was obtained from manufacturers' labeling.

Study Selection and Data Extraction:

All articles identified from the data sources were evaluated. Information deemed relevant was included for this review if it introduced new or well supported concepts or clarified clinical practice issues.

Data Synthesis:

The recognition and treatment of pain has become a major focus of healthcare professionals. The Joint Commission on Accreditation of Healthcare Organizations mandates compliance with recommended standards, outcome measures, and other initiatives. A general review of pain management and pharmacokinetic parameters are included.

Conclusions:

Oral modified-release products have enabled patients to better maintain pain control due to convenient dosing intervals and sustained blood concentrations. The differences between available oral modified-release products are half-life, cost, and formulation (excipients and drug-release properties).
Sitagliptin: A Dipeptidyl Peptidase IV Inhibitor for the Treatment of Type 2 Diabetes
Authors: Miller Shannon A , St. Onge Erin L
Published: July 2006

Objective:

TO review the pharmacology, pharmacokinetics, safety, and efficacy of sitagliptin, a dipeptidyl peptidase IV (DPP-IV) inhibitor in the management of type 2 diabetes mellitus.

Data Sources:

A MEDLINE search (1966–February 2006) was conducted for English-language articles using the terms dipeptidyl peptidase IV inhibitor, incretin, MK-0431, and sitagliptin. Abstracts from the American Diabetes Association annual meetings in 2004 and 2005 were included as sources of data.

Study Selection and Data Extraction:

Articles pertaining to the pharmacology of sitagliptin, its pharmacokinetics, safety and efficacy were reviewed.

Data Synthesis:

Sitagliptin is a potent, competitive, reversible inhibitor of the DPP-IV enzyme. It is eliminated renally, with a terminal half-life of 11.8–14.4 hours. In Phase II clinical trials, sitagliptin was found to be superior to placebo for the treatment of type 2 diabetes mellitus. Results of a small trial comparing sitagliptin with glipizide indicate that both treatments are comparable. The efficacy of sitagliptin has also been demonstrated when used as adjunctive therapy with metformin. Few adverse effects have been reported. Weight gain and hypoglycemia have not been seen with sitagliptin therapy.

Conclusions:

Based on its unique mechanism of action, sitagliptin will provide practitioners with an additional tool in the treatment of diabetes. Review of the literature to date implies sitagliptin may be effective as monotherapy in type 2 diabetes. In addition, existing evidence supports the use of sitagliptin as adjunct therapy to sulfonylureas and metformin. Another advantage of sitagliptin use is that it appears to be free from the adverse effects of weight gain and hypoglycemia that are associated with currently available treatments.
Police officers', social workers', teachers' and the general public's beliefs about deception in children, adolescents and adults
Authors: Vrij Aldert , Akehurst Lucy , Knight Sarah
Published: July 2006

Purpose. The present survey examined the beliefs of different occupational groups (police officers, social workers, teachers) and members of the general public about (i) cues to deception in young children (5‐ to 6‐year‐olds), adolescents (14‐ to 15‐year‐olds) and adults, and (ii) the underlying processes (emotions, cognitive load and attempted verbal and behavioural control), which may explain why cues to deceit do occur.

Method. Two hundred and six participants completed a ‘cues to deception’ and ‘processes underlying deception’ questionnaire for three different age groups (young children, adolescents and adults).

Results and discussion. The survey revealed that participants believed that liars are nervous, have difficulties in formulating their lies and do not fully endorse their lies. In general, participants associated more cues with deception than seems justified on the basis of deception literature. Participants generally associated the same cues to deceit for all three age groups but, when differences between age groups did emerge, this was most likely to be amongst teachers. Although participants believed that adults control their speech and behaviour more when they lie than adolescents and young children do, this did not result in participants believing that adults exhibit fewer cues to deceit. No major occupational differences emerged, although out of the four participating groups, teachers were most likely to associate cues with deception in young children.
QTL Analysis of Trabecular Bone in BXD F2 and RI Mice
Authors: Bower Abbey L , Lang Dean H , Vogler George P , Vandenbergh David J , Blizard David A , Stout Joseph T , McClearn Gerald E , Sharkey Neil A
Published: July 2006

A sample of 693 mice was used to identify regions of the mouse genome associated with trabecular bone architecture as measured using μCT. QTLs for bone in the proximal tibial metaphysis were identified on several chromosomes indicating regions containing genes that regulate properties of trabecular bone.

Introduction: Age-related osteoporosis is a condition of major concern because of the morbidity and mortality associated with osteoporotic fractures in humans. Osteoporosis is characterized by reduced bone density, strength, and altered trabecular architecture, all of which are quantitative traits resulting from the actions of many genes working in concert with each other and the environment over the lifespan. μCT gives accurate measures of trabecular bone architecture providing phenotypic data related to bone volume and trabecular morphology. The primary objective of this research was to identify chromosomal regions called quantitative trait loci (QTLs) that contain genes influencing trabecular architecture as measured by μCT.

Materials and Methods: The study used crosses between C57BL/6J (B6) and DBA/2J (D2) as progenitor strains of a second filial (F2) generation (n = 141 males and 148 females) and 23 BXD recombinant inbred (RI) strains (n ≈︁ 9 of each sex per strain). The proximal tibial metaphyses of the 200-day-old mice were analyzed by μCT to assess phenotypic traits characterizing trabecular bone, including bone volume fraction, trabecular connectivity, and quantitative measures of trabecular orientation and anisotropy. Heritabilities were calculated and QTLs were identified using composite interval mapping.

Results: A number of phenotypes were found to be highly heritable. Heritability values for measured phenotypes using RI strains ranged from 0.15 for degree of anisotropy in females to 0.51 for connectivity density in females and total volume in males. Significant and confirmed QTLs, with LOD scores ⩾4.3 in the F2 cohort and ⩾1.5 in the corresponding RI cohort were found on chromosomes 1 (43 cM), 5 (44 cM), 6 (20 cM), and 8 (49 cM). Other QTLs with LOD scores ranging from 2.8 to 6.9 in the F2 analyses were found on chromosomes 1, 5, 6, 8, 9, and 12. QTLs were identified using data sets comprised of both male and female quantitative traits, suggesting similar genetic action in both sexes, whereas others seemed to be associated exclusively with one sex or the other, suggesting the possibility of sex-dependent effects.

Conclusions: Identification of the genes underlying these QTLs may lead to improvements in recognizing individuals most at risk for developing osteoporosis and in the design of new therapeutic interventions.
Cholesterol-Sensing Receptors, Liver × Receptor α and β, Have Novel and Distinct Roles in Osteoclast Differentiation and Activation
Authors: Robertson Kirsten M , Norgård Maria , Windahl Sara H , Hultenby Kjell , Ohlsson Claes , Andersson Göran , Gustafsson Jan-Åke
Published: July 2006

The liver × receptor (α,β) is responsible for regulating cholesterol homeostasis in cells. However, our studies using the LXRα−/−, LXRβ−/−, and LXRα−/−β−/− mice show that both LXRα and β are also important for bone turnover, mainly by regulating osteoclast differentiation/activity.

Introduction: The liver × receptors (α,β) are primarily responsible for regulating cholesterol homeostasis within cells and the whole body. However, as recent studies show that the role for this receptor is expanding, we studied whether the LXRs could be implicated in bone homeostasis and development.

Materials and Methods: pQCT was performed on both male and female LXRα−/−, LXRβ−/−, LXRα−/−β−/−, and WT mice at 4 months and 1 year of age. Four-month-old female mice were additionally analyzed with reference to qPCR, immunohistochemistry, histomorphometry, transmission electron microscopy, and serum bone turnover markers.

Results: At the mRNA level, LXRβ was more highly expressed than LXRα in both whole long bones and differentiating osteoblast-like MC3T3-E1 and osteoclast-like RAW 264.7 cells. Four-month-old female LXRα−/− mice had a significant increase in BMD because of an increase in all cortical parameters. No difference was seen regarding trabecular BMD. Quantitative histomorphometry showed that these mice had significantly more endosteal osteoclasts in the cortical bone; however, these cells appeared less active than normal cells as suggested by a significant reduction in serum levels of cross-linked carboxyterminal telopeptides of type I collagen (CTX) and a reduction in bone TRACP activity. Conversely, the female LXRβ−/− mice exhibited no change in BMD, presumably because a significant decline in the number of the trabecular osteoclasts was compensated for by an increase in the expression of the osteoclast markers cathepsin K and TRACP. These mice also had a significant decrease in serum CTX, suggesting decreased bone resorption; however, in addition presented with an increase in the expression of osteoblast associated genes, bone formation markers, and serum leptin levels.

Conclusions: Our findings show that both LXRs influence cellular function within the bone, with LXRα having an impact on osteoclast activity, primarily in cortical bone, whereas LXRβ modulates trabecular bone turnover.
Osteocytes Use Estrogen Receptor α to Respond to Strain but Their ERα Content Is Regulated by Estrogen
Authors: Zaman Gul , Jessop Helen L , Muzylak Mariusz , De Souza Roberto L , Pitsillides Andrew A , Price Joanna S , Lanyon Lance L
Published: July 2006

The role of mechanical strain and estrogen status in regulating ERα levels in bone cells was studied in female rats. OVX is associated with decreased ERα protein expression/osteocyte, whereas habitual strain and artificial loading has only a small but positive effect, except on the ulna's medial surface, where artificial loading stimulates reversal of resorption to formation.

Introduction: Osteoporosis is the most widespread failure of bones' ability to match their architectural strength to their habitual load bearing. In men and women, the severity of bone loss is associated with bioavailability of estrogen. This association could result from the estrogen receptor (ER) involvement in bone cells' adaptive response to loading.

Materials and Methods: In vivo semiquantitative analysis of the amount of ERα protein per osteocyte was performed in immuno-cytochemically stained sections from control and loaded rat ulna, as well as tibias of ovariectomy (OVX) and sham-operated female rats. In vitro, the effect of exogenous estrogen (10−8 M) and mechanical strain (3400 μϵ, 1 Hz, 600 cycles) on the expression of ERα mRNA levels was assessed in ROS 17/2.8 cells in monolayers using real-time PCR and ER promoter activity. ERα translocation in response to exogenous estrogen and mechanical strain was assessed in both ROS 17/2.8 and MLO-Y4 cells.

Results: More than 90 percent of tibial osteocytes express ERα, the level/osteocyte being higher in cortical than cancellous bone. OVX is associated with decreased ERα protein expression/osteocyte, whereas in the ulna habitual strain and that caused by artificial loading had only a small but positive effect, except on the medial surface, where loading stimulates reversal of resorption to formation. In unstimulated osteocytes and osteoblasts in situ, and osteocyte-like and osteoblast-like cells in vitro, ERα is predominantly cytoplasmic. In vitro, both strain and estrogen stimulate transient ERα translocation to the nucleus and transient changes in ERα mRNA. Strain but not estrogen also induces discrete membrane localization of ERα.

Conclusions: Bone cells' responses to both strain and estrogen involve ERα, but only estrogen regulates its cellular concentration. This is consistent with the hypothesis that bone loss associated with estrogen deficiency is a consequence of reduction in ERα number/activity associated with lower estrogen concentration reducing the effectiveness of bone cells' anabolic response to strain.
Role of the Ram Domain and Ankyrin Repeats on Notch Signaling and Activity in Cells of Osteoblastic Lineage
Authors: Deregowski Valerie , Gazzerro Elisabetta , Priest Leah , Rydziel Sheila , Canalis Ernesto
Published: July 2006

Notch proteins belong to a family of single pass transmembrane receptors that are activated after interactions with the membrane-bound ligands Delta and Jagged/Serrate. We determined the pathways responsible for the inhibitory effects of Notch on osteoblastogenesis and the contributions of the RAM domain and ankyrin repeats to this process in cells of the osteoblastic lineage.

Introduction: Notch receptors play a role in osteoblast differentiation. Activation of Notch results in its cleavage and the release of its intracellular domain (NICD), which interacts with the CBF1/RBP-Jκ, Suppressor of Hairless, Lag-1 (CSL) family of transcription factors. The interaction is presumably mediated by the RBP-Jκ–associated module (RAM) of NICD, although the role of the ankyrin repeats is uncertain.

Materials and Methods: To determine the contributions of the RAM domain and ankyrin repeats to the inhibitory effects of Notch on osteoblastogenesis, ST-2 and MC3T3-E1 cells were transfected or transduced with vectors expressing NICD, RAM (NICD ΔRAM), and ankyrin (NICD ΔANK) deletion mutants.

Results: Notch increased the transactivation of transiently transfected 12xCSL-Luc constructs, containing 12 repeats of an RBP-Jκ/CSL binding site, and of the hairy and E (spl) (HES)-1 promoter. Deletion of the ankyrin repeats resulted in the loss of 12xCSL-Luc and HES-1 promoter transactivation, whereas deletion of the RAM domain caused a partial loss of 12xCSL-Luc and sustained HES-1 promoter transactivation. NICD overexpression inhibited osteocalcin mRNA levels and alkaline phosphatase activity in ST-2 cells, and deletion of the ankyrin repeats, and to a lesser extent of the RAM domain, resulted in loss of the NICD inhibitory effect. NICD inhibited Wnt signaling and deletion of ankyrin repeats or the RAM domain restored Wnt signaling activity.

Conclusions: The RAM domain and ankyrin repeats are required for Notch signaling and activity, and the CSL pathway is central to the inhibitory effect of Notch on osteoblastogenesis.
A Biomechanical Analysis of the Effects of Resorption Cavities on Cancellous Bone Strength
Authors: Hernandez Christopher J , Gupta Atul , Keaveny Tony M
Published: July 2006

We evaluated the effects of resorption cavities on cancellous bone strength using computational methods. Adding cavities to cancellous bone caused reductions in strength and stiffness that were greater than expected from the associated changes in bone volume and more pronounced when cavities were targeted to regions of high tissue strain.

Introduction: The amount of bone turnover in the skeleton has recently been implicated as a factor influencing bone strength. One mechanism proposed to explain this effect is that resorption cavities reduce the effective thickness of trabeculae and modify local stress distributions leading to reduced mechanical performance of the entire structure. In this study, we tested the plausibility of this mechanism.

Materials and Methods: High-resolution finite element models were created from μCT images of 16 vertebral cancellous bone samples, as well as from images of the samples in which cavities had been added digitally—either at regions of high strain (targeted) or placed at random on the bone surface (nontargeted). The effect of resorption cavities on predicted bone strength and stiffness was evaluated by comparing the relationships between mechanical properties and bone volume fraction among the three groups (the original images, those with nontargeted cavities, and those with targeted cavities).

Results: Addition of resorption cavities modified the relationship between mechanical properties and bone volume fraction in the finite element models such that, for a given bone volume fraction, stiffness and yield strength were reduced compared with the original images (p < 0.05). The differences in yield strength–volume fraction relationships between the original models and those with targeted cavities were significantly greater than those between the original models and those with nontargeted cavities (p < 0.05). None of the differences in predicted mechanical properties per unit bone volume fraction could be accounted for by 3D measures of microarchitecture.

Conclusions: Resorption cavities may influence cancellous bone strength and stiffness independent of their effect on bone volume. The effects of cavities on bone mechanical performance relative to bone volume are greater when cavities are targeted to regions of high strain and cannot be predicted using standard microarchitecture measures.