bluuebunny/crossref_metadata_2025 huggingface dataset:
Titanium(III) Chloride Mediated Reduction of Dicyanoalkenes
Authors: Sera Akira , Tsuzuki Toshihiro , Satoh Eishi , Itoh Kuniaki
Published: August 2006

The reaction of substituted dicyanoalkenes with aqueous titanium(III) chloride was examined. The dicyanoalkenes, which showed irreversible reduction characteristics on cyclic voltammograms, (typically, 2-cyano-3-phenylpropenenitrile), afforded cyclized and/or uncyclized hydrodimers, while those characterized by reversible reduction behavior, (typically, 2-cyano-3,3-diphenylpropenenitrile), yielded the corresponding saturated dinitriles. The reduction mechanism has been rationalized by taking account of the electron transfer from the Ti(III) species to the dicyanoalkenes, followed by protonation, or dimerization and cyclization.
The Substituent Effects on Solvolyses of thero-2-Aryl-1-methylpropyl Brosylates
Authors: Fujio Mizue , Goto Naomi , Dairokuno Tetsuro , Goto Mutsuo , Saeki Yoshihiro , Okusako Yoshimi , Tsuno Yuho
Published: August 2006

The solvolysis rates of threo-2-aryl-1-methylpropyl brosylates were determined for a series of substituents in acetic acid and 80% aq ethanol. The nonlinear substituent effect on the total rate was dissected with excellent precision into two linear LArSR relationships, each for the aryl-assisted (FkΔ) and unassisted (ks) processes. The use of the Brown σ+ for the dissection of the kΔ-correlation of this system failed to give any satisfactory results. The intermediate resonance demand of the kΔ solvolyses must be far beyond the scope of the Brown σ+ treatment with a fixed resonance demand of unity. The ρΔ and rΔ values for the kΔ process of thero-2-aryl-1-methylpropyl solvolysis were given to be −3.36 and 0.56 in AcOH, and −3.71 and 0.54 in 80% aq EtOH, respectively; they were identical to those for other aryl-assisted solvolyses, such as the neophyl system. Regardless of the structures of the reaction site, the resonance demands of β-aryl-assisted solvolysis of an identical mechanism all fall within a narrow range of 0.5–0.6 in the r scale of the continuous spectrum of resonance demands in aryl-conjugating carbocation solvolyses. The resonance demand of the aryl-assisted kΔ mechanism can be characterized in terms of this intermediate r value.
Epimerization of Chlorophyll Derivatives. V. Effects of the Central Magnesium and Ring Substituents on the Epimerization of Chlorophyll Derivatives
Authors: Mazaki Hitoshi , Watanabe Tadashi , Takahashi Terumi , Struck Andreas , Scheer Hugo
Published: August 2006

Kinetic and equilibrium features of the epimerization in six C132-epimer pairs of chlorophyllous pigments, namely chlorophyll (Chl) a/a′, Chl b/b′, pheophytin (Pheo) a/a′, Pheo b/b′, C20-chlorinated Chl (Cl–Chl) a/a′, and Cl–Pheo a/a′, catalyzed by bases (triethylamine, pyrrolidine, and piperidine) and by Lewis acids (magnesium acetylacetonate and magnesium chloride), have been studied in diethyl ether and methanol. A significant difference was noted in the epimerization rate and equilibrium epimeric composition among the pigment systems. The difference in the rate constants was rationalized in terms of the ease in C132-proton detachment, affected by the ring π-electron density which in turn depends on the electron donation or withdrawal by the central metal and/or ring substituents. For Lewis acid-catalysis, a dominant factor appears to be the stabilization of the C131-enolate anion via formation of a loose complex with extraneous Mg2+. A synergistic action of a base (triethylamine) and a Lewis acid (Mg2+) was observed for the epimerization or enolization of Pheo a/a′ in methanol.
Orientations of a Nematic Liquid Crystal in Sandwich-Type Cells Studied by Polarized Electronic Absorption Spectra
Authors: Kobayashi Michio , Kato Yoshinori , Koma Norio , Taki Naobumi , Maruyama Kazunori , Tanizaki Yoshie
Published: August 2006

Polarized electronic absorption spectra of a nematic liquid crystal (4-butyl-4′-ethoxyazobenzene, BEAB) were measured in sandwich-type cells to which no rubbing treatment was applied. These polarized spectra were utilized to evaluate the mean squares of the direction cosines of the transition moment, those of the molecular orientation axis, and the three-dimensional absorption components as a function of the cell gap. It has been shown that the inclinations of the transition moment for the 354 nm band (long-axis polarized) and the molecular orientation axis to the cell plane increase with the decrease in the cell gap while the absorption component for the 354 nm band normal to the cell plane decreases. These observations provide a quantitative support for the molecular orientation model proposed previously that the molecular long axis tends to be oriented parallel to the cell plane in the interface region and perpendicular in the bulk region. The thickness of the interface region has been estimated to be about 0.02 μm by a model calculation based on a discrete model for the orientation of the BEAB molecules in the cell.
Solvent Effects on the Formation and Decay of Ionic Intermediates for the Photoreduction of Anthraquinone by Triethylamine in Ethanol, Toluene, and Acetonitrile at Room Temperature
Authors: Hamanoue Kumao , Nakayama Toshihiro , Sasaki Hideyuki , Ikenaga Koichiro , Ibuki Kazuyasu
Published: August 2006

In toluene and ethanol containing triethylamine (TEA), a reaction of the lowest excited triplet state [3AQ(T1)] of anthraquinone (AQ) with ground-state TEA gave rise to the formation of an exciplex [3(AQ–TEA)*] which converted into a contact ion pair between the AQ radical anion (AQ−·) and the TEA radical cation (TEA+·). By an intramolecular proton transfer, this contact ion pair yielded anthrasemiquinone radical followed by the formation of 9,10-anthracenediol (AQH2); in ethanol, the monoanion (AQH−) of AQH2 was also produced. In ethanol/TEA, moreover, not only the decay rate constant of 3(AQ–TEA)* but also the quantum yield for the photoreduction of AQ were affected by the change of TEA concentration. This was interpreted in terms of the existence of a rapid interconversion between 3(AQ–TEA)* and atriplex [3(AQ–TEA2)*] of 3AQ(T1) with ground-state TEA. In contrast to the exciplex formation in ethanol and toluene, free AQ−· (and TEA+·) and 3(AQ–TEA)* [or a contact (or solvent-separated) ion pair between AQ−· and TEA+·] were produced in acetonitrile via the second and lowest excited triplet states of AQ, respectively: In the submicrosecond time regime, 3(AQ–TEA)* or the contact (or solvent-separated) ion pair dissociated into the radical ions (AQ−· and TEA+·) followed by their second-order reaction yielding finally AQH2 and AQH−.
Preparation of 1,4-Dienes from 2-(2-Hydroxyalkylseleno)benzothiazoles by the Reaction Involving Se → O Azaaromatic Ring Rearrangement
Authors: Shibata Koichi , Mitsunobu Oyo
Published: August 2006

The reactions of 2-(2-oxoalkylseleno)benzothiazoles with allylic Grignard reagents in the presence of BF3·OEt2 gave the corresponding 2-[(2-alkyl-2-hydroxy-4-pententyl or 2-alkyl-2-hydroxy-4-methyl-4-pentenyl)seleno]benzothiazoles which, on treatment with Ph3P and NaH, afforded 1,4-dienes in good to excellent yields.
Triplet Sensitized Quadricyclane-Norbornadiene Valence Isomerization of Methyl 5-(4-Biphenylyl)tetracyclo[3.2.0.2,70.4,6] heptane-1-carboxylate
Authors: Nakabayashi Kenichi , Takamuku Setsuo
Published: August 2006

The mechanism of valence isomerization between methyl 5-(4-biphenylyl) tetracyclo [3.2.0.2,70.4,6] heptane-1-carboxylate (1) and methyl 3-(4-biphenylyl)bicyclo[2.2.1]hepta-2,5-diene-2-carboxylate (2) under the triplet sensitization in benzene was studied by γ-radiolysis and pulse radiolysis. As an intermediate for the isomerization, an equilibrium state between a 1,3-biradical intermediate and a triplet state with the structure of norbornadiene has been estimated. The triplet energy levels of 1 and 2 were determined to be 59 and 57 kcal mol−1, respectively. The energy difference between the ground states of 1 and 2 was determined to be 18 kcal mol−1.
The Crystal Structure of Tetraethylene Glycol Complex of Sodium Tetraphenylborate
Authors: Ueda Takahiro , Nakamura Nobuo
Published: August 2006

The crystal of 2,2′-[oxybis(ethyleneoxy)] diethanol (tetraethylene glycol or TEG) complex of sodium tetraphenylborate, [Na(C8H18O5)]B(C6H5)4, is triclinic, Pl, with the unit cell dimensions: a = 1.1730 (2), b = 1.3212 (3), c = 1.1408 (2) nm, α = 108.83 (1), β = 112.40 (1), and γ = 67.42° (2), Z = 2. This compound contains binucear metal complex, ion, [Na(C8H18O5)]22+ The sodium ion is coordinated highly asymmetrically by six oxygens in two TEG.
Noncatalyzed Conjugate Addition Reaction of Alkylaluminum Compounds to 5-Methylene-2,4-imidazolidinedione Derivative
Authors: Sankhavasi Wongsiri , Kishikawa Keiki , Kohmoto Shigeo , Yamamoto Makoto , Yamada Kazutoshi
Published: August 2006

A noncatalyzed conjugate addition reaction of alkylaluminium compounds to 1,3-dibenzyl-5-methylene-2,4-imidazolidinedione 1 led to the exclusive formation of single and double conjugate adducts (2 and 3, respectively). The ratio of 2 : 3 depended on the reaction temperature and the concentration of 1.
Electroreductive Deoxygenation of Methanesulfonates of α-Hydroxy Esters via a Catalytic Selenation–Deselenation Sequence
Authors: Inokuchi Tsutomu , Sugimoto Tatsuya , Kusumoto Masahiko , Torii Sigeru
Published: August 2006

The methanesulfonates of α-hydroxy esters were converted to the corresponding deoxygenated esters in 70–88% yields by the indirect electrolysis with diphenyl diselenide as a recyclable reagent in a divided cell. This deoxygenation method may involve the formation of α-phenylselenoester by replacement of α-methylsulfonyloxyl group with phenylselenide anion followed by capture of the α-phenylseleno group with phenylselenide anion.
A New Synthetic Method for α-Oxo-β,γ-unsaturated Esters
Authors: Sugimura Hideyuki , Yoshida Kazuhiro
Published: August 2006

α-Oxo-β,γ-unsaturated esters have been prepared in moderate to good yields via a two-step procedure consisting of the boron trifluoride-promoted reaction of 2-(trimethylsiloxy)acrylic esters with acetals, followed by treatment with silica gel in benzene under reflux.
Pheophytinization of Eight Chlorophyll Derivatives in Aqueous Acetone
Authors: Mazaki Hitoshi , Watanabe Tadashi , Takahashi Terumi , Struck Andreas , Scheer Hugo
Published: August 2006

A significant difference in the pheophytinization rates among four C132-epimer pairs of chlorophylls is explained in terms of the inductive effects of ring substituents, and/or a strain at the macrocycle core due to the C132 stereochemistry. The rate-determining step appears to involve two protons at high [H+] and one proton at low [H+].
Framework Structure, Phase Transition, and Transport Properties in MIIZr4(PO4)6 Compounds (MII = Mg, Ca, Sr, Ba, Mn, Co, Ni, Zn, Cd, and Pb)
Authors: Nomura Katsuhiro , Ikeda Shoichiro , Ito Kaname , Einaga Hisahiko
Published: August 2006

The crystal structure, phase transition, electrical conduction behavior of various kinds of MIIZr4(PO4)6 (MIIZP) compounds (MII = Mg, Ca, Sr, Ba, Mn, Co, Ni, Zn, Cd, and Pb) have been investigated. The Mg, Co, Ni, and Zn compounds are of the β-Fe2(SO4)3-type structure and show an order-disorder transition between 600 and 720 °C; the Ca, Sr, Ba, Cd, and Pb compounds, however, are of the NASICON-type structure and do not show any phase transition between r.t. and 1000 °C. The Mn compound sintered at 900 °C shows the former characteristics (the phase transition temperature is around 560 °C), and that sintered above 900 °C the latter. The ZnZP and MnZP show the highest conductivity, ca. 2 × 10−3 and ca. 8 × 10−4 S cm−1 at 800 °C, in the β-Fe2(SO4)3- and the NASICON-type structure, respectively. The ionic size of the mobile cation is the predominant factor regarding ionic conduction in the zirconium phosphate framework.
Crystal and Molecular Structures of Acetoacetanilide, and o- and p-Chloroacetoacetanilides: X-Ray Crystallographic and MO Study
Authors: Kubozono Yoshihiro , Kohno Isao , Ooishi Kazuo , Namazue Sakuhiro , Haisa Masao , Kashino Setsuo
Published: August 2006

X-Ray structure analyses and MO calculations have been performed for acetoacetanilide (AAA), and o- and p-chloroacetoacetanilides (o-CAAA and p-CAAA) in order to elucidate the contribution of hydrogen bonding to crystal and molecular structures. The molecular conformations have been classified into two categories, planar for o-CAAA and nonplanar for AAA and p-CAAA. The molecular conformation of o-CAAA can be well-reproduced by the geometry optimization based on the AM1 (Austin Model 1) MO method, while those of AAA and p-CAAA are different from the optimized geometries. The deviation from the optimized structure can be explained on the basis of the formation of intermolecular hydrogen bonding and C–H···O=C interactions in the crystals. The hydrogen bonding of these compounds is discussed together with the infrared (IR) spectral data.
Dehydrative Glycosylation Using Heptabenzyl Derivatives of Glucobioses and Lactose
Authors: Koto Shinkiti , Morishima Naohiko , Shichi Sonoko , Haigoh Hisamitsu , Hirooka Motoko , Okamoto Mitsuko , Higuchi Takashi , Shimizu Koichi , Hashimoto Yosuke , Irisawa Terumi , Kawasaki Hidehiro , Takahashi Yasushi , Yamazaki Masayo , Mori Yoko , Kudo Keiko , Ikegaki Takako , Suzuki Sonoe , Zen Shonosuke
Published: August 2006

Dehydrative glycosylations of the 2-, 3-, 4-, and 6-OH groups of d-glucopyranose with hepta-O-benzyl derivatives of glucobioses (O-d-glucopyranosyl-(1→n)-d-glucopyranose; n = 2, 3, 4, or 6) and lactose, in the presence of a ternary mixture of p-nitrobenzenesulfonyl chloride, silver trifluoromethanesulfonate, and triethylamine in dichloromethane showed that the selectivity of the reaction depended on the anomeric configuration and the linking position to the reducing tribenzylglucose moiety of the nonreducing tetrabenzylglucosyl residue and on the class of the OH group to be glycosylated. The use of a quaternary mixture of p-nitrobenzenesulfonyl chloride, silver trifluoromethanesulfonate, N,N-dimethylacetamide, and triethylamine made all but the β(1→2)-linked biosyl donor undergo α-condensation. Several new linear trisaccharides were obtained via debenzylation of the condensates.
Effect of Artificial Boundary Lipid on the Membrane Dynamics of Human Glycophorin-Containing Liposome
Authors: Goto Mitsuaki , Sunamoto Junzo
Published: August 2006

Membrane dynamics of egg yolk phosphatidylcholine (egg PC) lipid bilayer which contains human glycophorin with an artificial boundary lipid, 1,2-dimyristoylamido-1,2-deoxyphosphatidylcholine (DDPC), were investigated by ESR spin probe technique. 2-Tridecyl-2-(4-hydroxy-4-oxoundecyl)-4,4-dimethyl-3-oxazolidinyloxy (5-NS), 2-octyl-2-(7-ethoxy-7-oxoheptyl)-4,4-dimethyl-3-oxazolidinyloxy (8-ENP), and 2-hexyl-2-(11-methoxy-11-oxoundecyl)-4,4-dimethyl-3-oxazolidinyloxy (12-MNS) were used as the spin probe to measure the fluidity in different regions and depths of the lipid bilayer membrane. Studies on lipid bilayer containing 5-NS revealed that the reconstitution of glycophorin to egg PC bilayer slightly decreased the membrane fluidity in the vicinity of membrane surface. Further addition of DDPC to this liposome brought about further decrease in the fluidity of this region. Liposomes containing 12-MNS revealed, however, that the addition of glycophorin had an opposite effect on the deep hydrophobic domain of the membrane by increasing the fluidity and the addition of DDPC to the liposome makes this domain less fluid. Corresponding changes were observed in the energy of activation for the rotation of 12-MNS during each case.
Thermochromism of 5,10,15,20-Tetraarylporphyrins at Low Temperature
Authors: Mori Yukie , Sasaki Masako , Daian Chie , Yamada Sachiko , Maeda Koko
Published: August 2006

5,10,15,20-Tetrakis(4-aminophenyl)porphyrin [T(p-NH2)PP] exhibited thermochromism in 2-methyltetrahydrofuran. In the electronic spectrum at 77 K four Q bands largely shifted to longer wavelength and relative intensities changed. The electronic spectrum of T(p-NH2)PP was also influenced by the nature of solvents. In strong hydrogen-bond accepting solvents Q bands were red-shifted and the resulting spectrum resembles that recorded at low temperature. Based on the solvent effect and substituent effects, the thermochromism of T(p-NH2)PP can be attributed to enhancement of hydrogen-bonds between p-NH2 group and solvent molecules at lower temperature, which causes increase of effective electron-donating ability of p-NH2 group. In alcoholic solvents T(p-NH2)PP and T(p-OH)PP showed another type of temperature dependence of absorption spectra.
Cyanodithioformate Complexes of Cyclopentadientylruthenium(II). Synthesis, Spectral and Electrochemical Study
Authors: Prasad Rajendra , Agarwala U C
Published: August 2006

A series of mono and binuclear cyanodithioformate (cdf) complexes with [RuIICpL2] [L = PPh3, AsPh3, SbPh3, (dppe)1/2, (dppm)1/2], exploiting its different coordination modes have been synthesized. Various physical and electrochemical methods have been used to characterize them. cdf by virtue of its vacant π* orbital introduces a low laying energy state in the compounds that facilitates Ru → cdf (dπ → π*) MLCT transition. MLCT band, upon dimerizaion shows red shift, whose magnitude depends upon site of attachment of second ruthenium moiety [, 3750 cm−1 for μ(η1–S; η1–S′) and 1010 cm−1 for μ(η1–S; η1–N) cdf complexes]. All complexes exhibit anodic oxidation peaks except binuclear μ(η1–S, η1–S′) cdf complex which exhibits reversible oxidation wave E1/2, −0.20 V vs. SCE in acetonitrite. Their spectral and electrochemical behavior are correlated with the σ, π characterstics of cdf and ruthenium moieties.
A New Synthesis of Pyrazolo[1,5-c]pyrimidines from Acetylenic β-Diketones
Authors: Marei Mohamed Gaber , Aly Dalia Mahmoud , Mishrikey Morcos Michael
Published: August 2006

5-Aryl-2-phenylpyrazolo[1,5-c]pyrimidine-7(6H)-thiones have been synthesized by the reaction of 1,5-diaryl-4-pentyne-1,3-diones with thiosemicarbazide and their reactions were studied. The pyrazolopyrimidinethiones give with certain electrophiles the respective 3-substituted 7-thiones. Their oxidation affords the corresponding disulfide. Moreover, they can be converted to the corresponding pyrazolopyrimidinones on reaction with alkaline hydrogen peroxide. The structure of the above compounds was confirmed from their spectral characteristics.
Studies on the Viscosities, Conductances, and Adiabatic Compressibilities of Some Tetraalkylammonium Perchlorates in 2-Methoxyethanol
Authors: Das Bijan , Hazra Dilip K
Published: August 2006

Electrical conductances, relative viscosities, and apparent molal adiabatic compressibilities of solutions of some symmetrical tetraalkylammonium perchlorates in 2-methoxyethanol (ME) have been reported. The conductance data have been analyzed by the 1978 Fuoss conductance equation and the viscosity data by the Jones–Dole equation for associated electrolytes. The ionic contribution to the limiting equivalent conductance, viscosity B coefficient and other thermodynamic parameters have been determined using the “reference electrolyte” method. The viscosity data show that the tetraalkylammonium ions are poorly solvated and behave as structure-breakers in 2-methoxyethanol. Analysis of the conductance as well as the compressibility data reveals the existence of strong ion-ion interactions in this solvent medium. The compressibility data also indicate the electrostriction of solvent molecules around the tetraethylammonium ion, while for the larger tetraalkylammonium ions they are accommodated inside the space between the coiled alkyl chains attached to the nitrogen atom.
Substituent Effects on the Aggregation of Bacteriochlorophyll d Homologues Purified from Chlorobium limicola
Authors: Nozawa Tsunenori , Ohtomo Katsunori , Takeshita Naohiro , Morishita Yumi , Osawa Masatoshi , Madigan Michael T
Published: August 2006

Six bacteriochlorophyll (BChl) d homologues were isolated from Chlorobium limicola. The absorption spectral profiles in hexane–dichloromethane and the solvent effects indicate that the aggregation property of the BChl d’s strongly depend on the nature of the peripheral substituents.
Photochemical Reactions of 4-Oxo Carboxylic Esters: Remote Hydrogen Abstraction and Cis-Trans Isomerization
Authors: Hasegawa Tadashi , Takashima Kumiko , Aoyama Hiromu , Yoshioka Michikazu
Published: August 2006

Upon irradiation, 2-benzyloxyethyl and 2-methoxyethyl 2-benzoylbenzoate underwent photocyclization through remote θ-hydrogen abstraction, though 2-benzyloxyethyl 3-benzoylacrylate underwent only cis-trans photoisomerization and 2-benzyloxyethyl 3-benzoylpropionate gave an intractable mixture. Conformational restriction is an important factor for remote hydrogen abstraction.
Formation of Charged Species in (n, γ) Activated 2-Bromopropionic Acid: An Atypical Case
Authors: Mishra Shuddhodan Prasad , Rakib-Uz-Zaman Md
Published: August 2006

(n, γ) Activation of dibromomethane, tribromomethane, 1-bromonaphthalene, 2-bromophenol and 2-bromopropionic acid has been studied in liquid phase by Charge Plate Technique. A (Ra–Be) neutron source of 300 mCi having an integral flux of 3.2 × 106 n cm−2 s−1 was used for the production of energetic bromine species. Both anionic and cationic charged species have been collected on charged plates for the targets used except in 2-bromopropionic acid where cathode activity was found nil. This result is unique and never observed before for pure liquid bromocompounds using charge plate collection experiments.
Synthesis and Biological Evaluation of Pyridooxazine–Tetrahydroisoquinoline Derivatives as MDR Modulators
Authors: Ma Chen , Liu Shao-Jie , Xin Liang , Zhang Qun , Ding Kai , Falck J R , Shin Dong-Soo
Published: August 2006

Pyridooxazine–tetrahydroisoquinoline derivatives were designed and synthesized for MDR modulating activity. Pyridooxazin-2-one scaffolds were constructed in a one-pot annulation of N-substituted-2-chloroacetamides with 2-bromo-3-hydroxy pyridine via Smiles rearrangement. The Pictet–Spengler cyclization to form tetrahydroisoquinoline ring afforded target compounds in 17–37% overall yields. Some of these compounds exhibited multidrug resistance (MDR) reversing activity.
From Industrial Colorants to Single Photon Sources and Biolabels: The Fascination and Function of Rylene Dyes
Authors: Herrmann Andreas , Müllen Klaus
Published: August 2006

Perylene dyes are key chromophores in dyestuff chemistry. The solubility, absorption, and emission behavior of this class of materials can be efficiently controlled by functionalization using a variety of different synthetic procedures. Moreover, these chemical modifications have allowed their widespread application as functional dyes. New NIR-absorbers have been synthesized by introducing additional naphthalene units to the perylene scaffold to form the higher homologues of the series of rylenediimides. Such dyes can be used for laser welding and laser marking of polymers. Highly fluorescent nanoparticles containing multiple chromophores have been prepared by decorating polyphenylene dendrimers with rylenes on the surface. Depending on the chromophoric interactions, these types of materials can serve as single photon sources. When in addition to the surface, the interior and the dendritic scaffold are equipped with donor and acceptor dyes, synthetic light-harvesting complexes are obtained, which collect light from the whole visible spectrum. Due to the outstanding chemical and photochemical stabilities as well as their high fluorescence quantum yields, the perylene- and terrylenediimides have been established as key chromophores for single molecule spectroscopy allowing photophysical processes, e.g. energy and electron transfer to be studied on the single molecule level over extended periods of time. With water soluble rylene dyes single molecule measurements regarding biological problems can now be addressed as well. The same set of favorable properties also makes the rylene dyes excellent candidates for applications in organic electronic devices.
Isolation and Characterization of an Allenylthioketene and 4-Methylenecyclobutenethiones Generated by Thermal Reaction of Alkynyl Propargyl Sulfides
Authors: Aoyagi Shigenobu , Sugimura Katsuaki , Kanno Nobuya , Watanabe Dai , Shimada Kazuaki , Takikawa Yuji
Published: August 2006

Alkynyl propargyl sulfides underwent [3,3] sigmatropic rearrangement followed by ring closure to afford isolable 4-methylenecyclobutenethiones, and an intermediary allenylthioketene 2 was isolated by heating t-butyldimethylsilylethynyl propargyl sulfide.
Highly Selective Fluoride Ion Detection Based on a Fluorescent Alizarin–o-Aminomethylphenylboronic Acid Ensemble in Aqueous MeOH Solution
Authors: Kubo Yuji , Ishida Tomohisa , Minami Tsuyoshi , James Tony D
Published: August 2006

A self-organized fluorescent sensor consisting of alizarin and o-aminomethylphenylboronic acid 1 is presented, the ensemble shows highly selective fluoride ion-response in H2O–MeOH (1:4 w/w) at pH 5.5. Compound 1 (pKa = 5.63) at pH 5.5 in the solution follows the equilibrium: alizarin–1 + H+1H+ + alizarin. Thus, F− added into the solution preferably binds to 1H+ to allow the ensemble to release alizarin, resulting in a fluorescence quenching.
Recovery of Lighter Fuels from Petroleum Residual Oil by Oxidative Cracking with Steam over Zr–Al–FeOx Catalyst
Authors: Fumoto Eri , Tago Teruoki , Masuda Takao
Published: August 2006

Zirconia-including iron catalyst with high durability was successfully prepared which had high activity for recovering lighter fuels from petroleum residual oil in a steam atmosphere. Zirconia dispersed highly in iron catalyst supplied enough amount of active oxygen species from steam into iron oxide lattice. Lattice oxygen in iron oxide reacted with heavy oil. Thus, oxidative cracking of heavy oil with steam was accelerated over iron catalyst with highly dispersed zirconia without any lack of lattice oxygen of iron oxide.
Detection of citrate overdose in critically ill patients on citrate-anticoagulated venovenous haemofiltration: use of ionised and total/ionised calcium
Authors: Bakker Andries J. , Boerma E. Christiaan , Keidel Halbe , Kingma Peter , van der Voort Peter H.J.
Published: August 2006

Clin Chem Lab Med 2006;44:962–6.
Establishment of reference distributions and decision values for thyroid antibodies against thyroid peroxidase (TPOAb), thyroglobulin (TgAb) and the thyrotropin receptor (TRAb)
Authors: Jensen Esther A. , Petersen Per Hyltoft , Blaabjerg Ole , Hansen Pia Skov , Brix Thomas H. , Hegedüs Laszlo
Published: August 2006

Clin Chem Lab Med 2006;44:991–8.
Aminothiols in human brain tumors
Authors: Bičíková Marie , Kříž Lubomír , Mohapl Milan , Burkoňová Dominika , Tallová Jaroslava , Hušek Petr
Published: August 2006

Clin Chem Lab Med 2006;44:978–82.
Evaluation of the analytical performance of the advanced method for cardiac troponin I for the AxSYM platform: comparison with the old method and the Access system
Authors: Storti Simona , Prontera Concetta , Parri Maria Serena , Iervasi Annalisa , Vittorini Simona , Emdin Michele , Carlo Zucchelli Gian , Longombardo Giovanni , Migliorini Paola , Clerico Aldo
Published: August 2006

Clin Chem Lab Med 2006;44:1022–9.
Optimization of an enzymatic method for the determination of lysosomal N-acetyl-β-D-hexosaminidase and β-glucuronidase in synovial fluid
Authors: Marciniak Justyna , Zalewska Anna , Popko Janusz , Zwierz Krzysztof
Published: August 2006

Clin Chem Lab Med 2006;44:933–7.
Fifteen polymorphisms in endothelin-1, endothelin-2 and endothelin-receptor-A genotyped by four duplex assays and seven simple assays on a LightCycler using hybridization probes
Authors: Arjomand-Nahad Farhad , Landt Olfert , Stangl Karl , Diefenbach Konstanze , Roots Ivar
Published: August 2006

Endothelins (EDNs) are peptides, produced by various tissues, with potent vasoactive and mitogenic properties. Endothelin actions are mediated via specific G protein-coupled receptors of two subtypes, endothelin-receptor-A (EDNRA) and endothelin-receptor-B (EDNRB). Some polymorphisms of the

Clin Chem Lab Med 2006;44:929–32.
Haptoglobin polymorphism in patients with preeclampsia
Authors: Depypere Herman T. , Langlois Michel R. , Delanghe Joris R. , Temmerman Marleen , Dhont Marc
Published: August 2006

Clin Chem Lab Med 2006;44:924–8.
Mechanical modulation at the lamellar level in osteonal bone
Authors: Gupta H.S. , Stachewicz U. , Wagermaier W. , Roschger P. , Wagner H.D. , Fratzl P.
Published: August 2006

The secondary osteon is the fundamental building block of compact cortical bone at the tissue level. Light and scanning electron microscopy have shown that the osteon consists of a laminated cylindrical composite of mineralized collagen fibril lamellae ∼5–7 μm thick. Using scanning nanoindentation and quantitative backscattered electron imaging on secondary osteons from the human femoral midshaft, we found that the indentation modulus shows a periodic variation between ∼24 GPa and ∼27 GPa within a single lamella. The average lamellar value remains nearly constant across the osteon and increases abruptly to more than 30 GPa at the interstitial bone interface. The local mineral content, determined from quantitative backscattered electron imaging at the indented locations, shows also a lamellar level modulation and is positively correlated with the indentation modulus at the same tissue position. We propose that such a mechanically and compositionally modulated structure may be an effective crack-stopping mechanism in bone.
Investigation of the viscoelasticity of human osteosarcoma cells using a shear assay method
Authors: Cao Yifang , Bly Randy , Moore Will , Gao Zhan , Cuitino Alberto M. , Soboyejo Wole
Published: August 2006

This paper presents a shear assay method for the determination of the viscoelastic properties of biological cells. The method was applied to the measurement of the viscoelastic properties of human osteosarcoma (HOS) cells. It involves a combination of shear assay experiments and digital image correlation techniques. Following in situ observations of cell deformation during shear assay experiments, a digital image correlation (DIC) technique was used to determine the local displacement and strain fields. The creep curves were also extracted from multiple digital images that were used to extract the time dependence of local strain under constant stress conditions. The measured creep curves were well described by a generalized viscoelastic Maxwell model. The extracted elastic and viscous parameters were in good agreement with results obtained from prior studies with other techniques. The results also suggested that the nucleus is stiffer than the surrounding cytoplasm of HOS cells.
Hydration effects on the micro-mechanical properties of bone
Authors: Bembey A.K. , Bushby A.J. , Boyde A. , Ferguson V.L. , Oyen M.L.
Published: August 2006

Bone is a composite material with hydroxyapatite mineral, collagen, and water as primary components. Water plays an important role in maintaining the mechanical integrity of the composite, but the manner in which water interacts within the collagen and mineral at ultrastructural length-scales is poorly understood. The current study examined changes in the mechanical properties of bone as a function of hydration state. Tissues were soaked in different solvents and solutions, with different polarities, to manipulate tissue hydration. Mineralized bone was characterized using nanoindentation creep tests for quantification of both the elastic and viscoelastic mechanical responses, which varied dramatically with tissue bathing solution. The results were considered within the context of solution physical chemistry. Selectively removing and then replacing water provided insights into the ultrastructure of the tissues via the corresponding changes in the experimentally determined mechanical responses.
Example of microprocessing in a natural polymeric fiber: Role of reeling stress in spider silk
Authors: Elices M. , Guinea G.V. , Plaza G.R. , Real J.I. , Pérez-Rigueiro J.
Published: August 2006

Spider silk fibers were obtained by the monitored forced silking method. This procedure allows measurement of the silking force during the process and retrieving the fibers so their tensile behavior can be characterized. Silking conditions, including the reeling speed and the use of an anaesthetising gas, were varied to ascertain their influence on the tensile properties of the silk. In all cases, it was found that the tensile properties are determined by the silking stress, obtained by dividing the silking force by the diameter of the fiber. This suggests that the sophisticated spinning system of the spider can be characterized essentially by a single parameter, which controls the properties of spider silk almost independently of the reeling conditions.
Computer aided adhesive and assembly optimization method: Biomimetic optimization of adhesive joints
Authors: Munzinger M. , Kraft O. , Mattheck C.
Published: August 2006

Over millions of years, natural constructions have been developed by evolutionary processes in nature with the general aim to generate high-performance structures with minimum material consumption. It is well known that one of the major strategies is to reach a largely homogeneous material load in the biological structure. In this paper, we demonstrate that this natural design principal applies not only to the macroscopic level but also to microstructural optimization, and in particular, to adhesive joints in nature. Furthermore, we introduce the computer aided adhesive and assembly optimization method (CA3O), which transfers the natural mechanically stimulated growth processes to technical adhesive joints by means of the finite element method.
Dynamic nanomechanical response of nacre
Authors: Mohanty Bedabibhas , Katti Kalpana S. , Katti Dinesh R. , Verma Devendra
Published: August 2006

Nacre, the shiny inner layer of mollusk shells is a model biomimetic nanocomposite system. Its exceptional mechanical properties have been the inspiration for materials scientists for several decades. Nacre exhibits a layered brick and mortar structure. It is composed of 95% inorganic (aragonitic CaCO3) phase and 5% organic (mainly proteins and polysaccharides) phase that are arranged in interlocked brick and mortar architecture with the mineral as bricks and organics as the mortar. In the current work, we describe the dynamic nanomechanical behavior of nacre using dynamic nanoindentation (nano-DMA) experiments. Two sets of loads were applied to obtain the dynamic response from varying depths in nacre. These tests were performed at three different frequencies (25, 50, and 100 Hz) to study the effect of frequency on the dynamic properties of nacre. The loss modulus (E″) and the loss factor (tan δ) were measured. Both of these parameters were observed to increase with increase in depth. Significant increase in tan δ was observed with the increase in frequency. Photoacoustic Fourier transform infrared spectroscopic studies on nacre indicate the presence of water in nacre. This water may be present at nanograin interfaces in nacre platelets, at organic–inorganic interfaces, and also in the organic phase in nacre. We believe that water is one of the significant contributors to the viscoelasticity of nacre. Our results indicate that the aragonite platelets in nacre may also contribute to viscoelasticity.
Micromechanical properties of biological silica in skeletons of deep-sea sponges
Authors: Woesz Alexander , Weaver James C. , Kazanci Murat , Dauphin Yannicke , Aizenberg Joanna , Morse Daniel E. , Fratzl Peter
Published: August 2006

The silica skeleton of the deep-sea spongeEuplectella aspergillumwas recently shown to be structured over at least six levels of hierarchy with a clear mechanical functionality. In particular, the skeleton is built of laminated spicules that consist of alternating layers of silica and organic material. In the present work, we investigated the micromechanical properties of the composite material in spicules ofEuplectella aspergillumand the giant anchor spicule ofMonorhaphis chuni. Organic layers were visualized by backscattered electron imaging in the environmental scanning electron microscope. Raman spectroscopic imaging showed that the organic layers are protein-rich and that there is an OH-enrichment in silica near the central organic filament of the spicule. Small-angle x-ray scattering revealed the presence of nanospheres with a diameter of only 2.8 nm as the basic units of silica. Nanoindentation showed a considerably reduced stiffness of the spicule silica compared to technical quartz glass with different degrees of hydration. Moreover, stiffness and hardness were shown to oscillate as a result of the laminate structure of the spicules. In summary, biogenic silica from deep-sea sponges has reduced stiffness but an architecture providing substantial toughening over that of technical glass, both by structuring at the nanometer and at the micrometer level.
Influence of strain rate on the mechanical behavior of cortical bone interstitial lamellae at the micrometer scale
Authors: Vanleene Maximilien , Mazeran Pierre-Emmanuel , Tho Marie-Christine Ho Ba
Published: August 2006

Investigations of bone mechanical properties are of major importance for bone pathology research, biomaterials, and development of in vivo bone characterization devices. Because of its complex multiscale structure, assessment of bone microstructure is an important step for understanding its mechanical behavior. In this study, we have investigated the strain rate influence on the mechanical properties of interstitial lamellae on two human femur bone samples. Nanoindentation tests were performed with the continuous stiffness measurement technique. Young's modulus and hardness were calculated using the Oliver and Pharr method. A statistical significant influence of strain rate on hardness was found (p < 0.05) showing a viscoplastic behavior of interstitial bone at the micrometer scale. This phenomenon may reflect the role of the organic component in the bone matrix mechanical behavior.
Biomimetic structures for mechanical applications by interfering laser beams: More than solely holographic gratings
Authors: Daniel Claus
Published: August 2006

A variety of biological materials composed of hierarchical phase composites can be found. These biological materials successfully combine impressive toughness with high stiffness and strength. Deposition techniques combined with high-power laser beams can imitate biological structures in technical systems. Interference phenomena, such as surface scattering, Lloyd's mirror arrangements, or interference of coherent beams, can be used to create these biomimetic long-range ordered structures on the scale of nanometers to micrometers. These structures are not limited to topographic texturing, as in the case of holographic gratings; rather, they can also create composite structures and phase transformations. This article presents a brief overview of interference techniques, their possibilities, and their limits.
Deformation of the cell nucleus under indentation: Mechanics and mechanisms
Authors: Vaziri A. , Lee H. , Mofrad M.R. Kaazempur
Published: August 2006

Computational models of the cell nucleus, along with experimental observations, can help in understanding the biomechanics of force-induced nuclear deformation and mechanisms of stress transition throughout the nucleus. Here, we develop a computational model for an isolated nucleus undergoing indentation, which includes separate components representing the nucleoplasm and the nuclear envelope. The nuclear envelope itself is composed of three separate layers: two thin elastic layers representing the inner and outer nuclear membranes and one thicker layer representing the nuclear lamina. The proposed model is capable of separating the structural role of major nuclear components in the force-induced biological response of the nucleus (and ultimately the cell). A systematic analysis is carried out to explore the role of major individual nuclear elements, namely inner and outer membranes, nuclear lamina, and nucleoplasm, as well as the loading and experimental factors such as indentation rate and probe angle, on the biomechanical response of an isolated nucleus in atomic force microscopy indentation experiment.
Herb–Drug Interactions in Oncology: Focus on Mechanisms of Induction
Authors: Meijerman Irma , Beijnen Jos H. , Schellens Jan H.M.
Published: August 2006

Learning Objectives

After completing this course, the reader will be able to: Describe the possible pharmacokinetic interactions between complementary alternative medicines and oncolytic drugs and the clinical consequences thereof.Define the role of the nuclear receptors PXR, CAR, and VDR in herb–drug interactions.Discuss methods to measure induction of drug-metabolizing enzymes and transporters.

Access and take the CME test online and receive 1 AMA PRA Category 1 Credit™ at CME.TheOncologist.com

An increasing number of cancer patients are using complementary and alternative medicines (CAM) in combination with their conventional chemotherapeutic treatment. Considering the narrow therapeutic window of oncolytic drugs, this CAM use increases the risk of clinically relevant herb–anticancer drug interactions. Such a relevant interaction is that of St. John's wort with the anticancer drugs irinotecan and imatinib. It is, however, estimated that CAM–anticancer drug interactions are responsible for substantially more unexpected toxicities of chemotherapeutic drugs and possible undertreatment seen in cancer patients.

Induction of drug-metabolizing enzymes and ATP-binding cassette drug transporters can be one of the mechanisms behind CAM–anticancer drug interactions. Induction will often lead to therapeutic failure because of lower plasma levels of the anticancer drugs, and will easily go unrecognized in cancer treatment, where therapeutic failure is common.

Recently identified nuclear receptors, such as the pregnane X receptor, the constitutive androstane receptor, and the vitamin D-binding receptor, play an important role in the induction of metabolizing enzymes and drug transporters. This knowledge has already been an aid in the identification of some CAM probably capable of causing interactions with anticancer drugs: kava-kava, vitamin E, quercetin, ginseng, garlic, β-carotene, and echinacea. Evidently, more research is necessary to prevent therapeutic failure and toxicity in cancer patients and to establish guidelines for CAM use.
Partnerships in Oncology and Radiology: The Role of Radiology in the Detection, Staging, and Follow-up of Lung Cancer
Authors: Lobrano Mary Beth
Published: August 2006

Learning Objectives

After completing this course, the reader will be able to: Describe the limitations of chest radiographs in detecting lung cancers.Discuss the current status of lung cancer screening.Identify the benefits and limitations of PET/CT in the diagnosis, staging, and follow-up of lung cancer.

Access and take the CME test online and receive 1 AMA PRA Category 1 Credit™ at CME.TheOncologist.com

In this review, I examine the multifaceted role of radiology in the diagnosis, staging, and management of lung cancer, highlighting new applications and modalities such as computer-aided detection of lung nodules and positron emission tomography/computed tomography for staging and monitoring response to therapy. Lung cancer screening is also discussed.
RFA for Liver Tumors: Does It Really Work?
Authors: Higgins Heather , Berger David L.
Published: August 2006

The use of radiofrequency ablation (RFA) is increasing in the treatment of both primary and metastatic hepatic tumors. However, the role of RFA has yet to be clearly defined in patients who are still considered amenable to surgical intervention. Future prospective studies are needed to define whether RFA can be used as an alternative to surgery in certain patient populations. In the interim, radiofrequency ablation technology will continue to advance and serve as both a palliative and potentially curative intervention for individuals with hepatic tumors.
Combined Modality Therapy for Stage III Non-Small Cell Lung Cancer
Authors: Stinchcombe Thomas E. , Fried Daniel , Morris David E. , Socinski Mark A.
Published: August 2006

Learning Objectives

After completing this course, the reader will be able to: Discuss the evidence to date on the role of chemotherapy in the treatment of stage III non-small cell lung cancer (NSCLC).Discuss the evidence to date on the role of radiotherapy in the treatment of stage III NSCLC.Describe ongoing chemotherapy trials and radiotherapy trials in stage III NSCLC.

Access and take the CME test online and receive 1 AMA PRA Category 1 Credit™ at CME.TheOncologist.com

Lung cancer remains the leading cause of cancer death in the U.S. among both men and women. Approximately 45% of patients present with stage III disease. A proportion of these patients is amenable to surgical resection; however, the majority are “unresectable.” For patients with unresectable stage IIIA/B disease, thoracic radiation therapy (TRT) was considered the standard of care until the late 1980s despite a very poor 5-year survival rate. Several clinical trials demonstrated that the combination of chemotherapy and TRT was superior to TRT alone. Based on these data, combined modality therapy became the standard of care for patients with good performance status. Recent trials have shown that concurrent chemoradiotherapy offers a significant survival advantage over sequential chemoradiotherapy. Despite a substantial number of clinical trials, important questions on the optimal treatment paradigm remain. The most effective chemotherapy combination, the use of induction or consolidation chemotherapy in addition to the concurrent portion of therapy, and the optimal dose of chemotherapy with concurrent TRT have yet to be determined. The optimal total dose, fractionation, acceleration, treatment volume, and tumor targeting remain questions related to the TRT portion of therapy. Although significant progress has been made, the majority of patients experience locoregional or distant progression of their disease and die within 5 years of diagnosis. Thus, continued development and participation in clinical trials is crucial to further improvements in the treatment of patients with stage III disease.
Efficacy and Safety of Zoledronic Acid in Patients with Breast Cancer Metastatic to Bone: A Multicenter Clinical Trial
Authors: Cartenì Giacomo , Bordonaro Roberto , Giotta Francesco , Lorusso Vito , Scalone Simona , Vinaccia Vincenza , Rondena Roberta , Amadori Dino
Published: August 2006

Purpose. This study evaluated the efficacy and safety of zoledronic acid in breast cancer patients with newly diagnosed bone metastases.

Materials and Methods. Patients diagnosed with bone metastases ≤ 6 weeks prior to first visit were enrolled. Zoledronic acid (4 mg) was administered via a 15-minute infusion every 3 or 4 weeks for 12 infusions. Skeletal-related events (SREs) were defined as pathologic bone fractures, spinal cord compression, surgery to bone, radiation therapy to bone, and hypercalcemia of malignancy. Primary efficacy end points were the proportion of patients with at least one SRE and the time to first SRE. Secondary end points included pain, analgesic use, and quality of life.

Results. Among 312 patients enrolled, 30% experienced at least one SRE during the 12-month study, and 22% experienced only one SRE. The median time to first SRE was not reached in the intent-to-treat population. Mean pain and analgesic scores declined from baseline, and quality-of-life scores remained stable to study end. The most frequently reported adverse events, regardless of relationship to study drug, were pyrexia (22%) and bone pain (10%). Serum creatinine levels did not significantly increase from baseline throughout the study.

Conclusions. Breast cancer patients with newly diagnosed bone metastases who were treated with zoledronic acid had a low incidence of SREs compared with patients who received placebo in randomized phase III trials, and pain was decreased from baseline. This study demonstrated the favorable risk:benefit ratio of zoledronic acid for the prevention of skeletal complications.