bluuebunny/crossref_metadata_2025_split huggingface dataset:
Helical Supramolecular Architectures of Self-Assembled Linear π-Systems
Authors: Praveen Vakayil K , Babu Sukumaran S , Vijayakumar Chakkooth , Varghese Reji , Ajayaghosh Ayyappanpillai 
Published: October 2008

Abstract
The present account describes the summary of the recent developments to the design of helical self-assemblies of linear π-conjugated molecules, particularly of oligo(p-phenylenevinylenes) (OPVs) and oligo(p-phenyleneethynylenes) (OPEs). The design strategy involves functionalization of π-conjugated backbones with achiral and chiral alkoxy side chains and hydroxymethyl end groups. Self-organization of these molecules in nonpolar hydrocarbon solvents resulted in a variety of supramolecular architectures such as tapes, helices, vesicles, and tubules. These supramolecular structures eventually lead to the formation of entangled networks resulting in gelation of solvents. It has been observed that OPVs in nonpolar solvents prefer to form supramolecular tapes whereas the corresponding OPEs form nano- to microsized vesicles and bundled fibers. Attachment of chiral motifs to OPVs and OPEs resulted in the formation of helical structures with a preferred handedness. The “sergeants and soldiers” co-assembly approach to chirality induction and amplification is efficient in these systems in the gel state. These results highlight the importance of the subtle difference in the strength of π–π interaction in gel forming linear π-systems to the creation of hierarchical architectures with different size and shape, particularly helical structures.
Mechanism and Kinetics of Cyanide Decomposition by Ferrate
Authors: Kamachi Takashi , Nakayama Tomonori , Yoshizawa Kazunari 
Published: October 2008

Abstract
The mechanism of cyanide oxidation by ferrate in water is discussed using DFT computations in the framework of the polarizable continuum model. The reactivity of three oxidants, nonprotonated, monoprotonated, and diprotonated ferrates is evaluated. This reaction is initiated by a direct attack of an oxo group of ferrate to the carbon atom of cyanide, followed by an H-atom transfer from cyanide to another oxo group to lead to an intermediate having cyanate (NCO−) as a ligand. The produced cyanate is oxidized by an oxo ligand of ferrate and exogenous oxygen molecule to CO2 and NO2−. The initial C–O bond formation is found to be the rate-determining step in this reaction. The activation energy for the C–O bond formation is 51.9 kJ mol−1 for nonprotonated ferrate, 44.4 kJ mol−1 for monoprotonated ferrate, and 41.4 kJ mol−1 for diprotonated ferrate, which indicates that the oxidizing power of the three oxidants is in the order of nonprotonated ferrate &lt; monoprotonated ferrate &lt; diprotonated ferrate. The general energy profile for cyanide oxidation by ferrate is downhill toward the product direction after the C–O bond formation, so cyanide is readily converted to the final products in water. The reaction kinetics of this reaction are analyzed from the calculated energy profile and experimentally determined pKa values.
Assessment of the Effect of Mixing Rules on Transport Properties of Gas Mixtures
Authors: Mohammad-Aghaie Delara , Papari Mohammad Mehdi , Moghadasi Jalil , Haghighi Behzad 
Published: October 2008

Abstract
The purpose of this paper is to examine the effect of six different mixing rules on the calculated transport properties including viscosities and thermal conductivities of some binary and ternary gas mixtures. These properties are calculated using pair potential energies of the systems obtained from the inversion procedure. The Chapman–Enskog theory and Schreiber’s method are employed to calculate viscosity and thermal conductivity of different mixtures, respectively. Different mixing rules do not behave the same in predicting the two aforementioned properties. The Fit (MADAR-2) mixing rule gives rise to more acceptable viscosity values, while the Halgren-HHG rule stands over other mixing rules in predicting thermal conductivity. It is found that, when the mixture components are similar in size, different mixing rules often do not change the errors in calculated properties more than ±1%. However, as the size similarity decreases, the effect of applied mixing rules becomes more important. In this case, different mixing rules are able to change the errors in calculations at most ±3.5%. The collision diameters (σ) of our studied mixture components, vary from 2.641 Å for He, to 5.26 Å for R125. The energy scaling parameters (ε) of mixture components range from 10.956 K for He to 475.76 K for C4H10.
Dynamic Quantum Isotope Effects on Multiple Proton-Transfer Reactions
Authors: Shigeta Yasuteru , Miyachi Hideaki , Matsui Toru , Hirao Kimihiko 
Published: October 2008

Abstract
In order to investigate static quantum isotope effects on the stability of proton-transferred structures, we defined an effective quantal potential energy hypersurface (EQPES), which includes mass-dependent quantum effects. We demonstrated the difference between the ordinary potential energy surface and EQPES of the double well potential as a simple example. The minimum energy path on EQPES describes the zero-point energy-corrected structures and tunneling motion, which is characterized as a classically forbidden motion. We also performed the EQPES analysis of model proton-transfer reactions in DNA base pairs. It was found that the double proton-transferred structure of an adenine–thymine (AT) pair is quantum mechanically unstable and that of a guanine–cytosine (GC) pair is stable within a least uncertainty regime. In order to investigate dynamic quantum isotope effects on the stability of the proton-transferred structures, we performed quantal cumulant dynamics (QCD) simulations of the GC pair. Results show that the proton-transferred structure of the protonated isotopomer is dynamically unstable though the EQPES analysis predicts its stability. It is relevant to include dynamic effects in the investigation of the quantum isotope effects on geometric stability of systems with a small energy gap between global and metastable structures.
Specific Oxidative Dehydrogenation Reaction Mechanism over Vanadium(IV/III) Sites in TiO2 with Uniform Mesopores under Visible Light
Authors: Izumi Yasuo , Konishi Kazushi , Yoshitake Hideaki 
Published: October 2008

Abstract
Selective oxidation under visible light is attractive for application in environment-benign societies. Oxidative dehydrogenation of ethanol proceeds over mesoporous V-doped TiO2 under visible light in clear contrast to ethanol dehydrogenation over crystalline TiO2 doped or undoped with V and inactive mesoporous TiO2. The red-ox states of VIV and VIII were detected using X-ray spectroscopies. In this paper, kinetic measurements of each catalytic step and X-ray spectroscopic monitoring under catalytic reaction conditions are correlated. The ethanol conversion to acetaldehyde in the absence of O2 was monitored under visible light coupled with reduction of VIV to VIII species based on V Kβ5,2 emission and V Kβ5,2-selecting X-ray absorption fine structure spectra. The oxidative dehydrogenation of dissociatively adsorbed ethoxyl species proceeded in O2 under visible light with formation rates 38% of steady photo-catalysis in ethanol + O2. The acetaldehyde desorption step by H subtraction from ethoxyl species on VIII was found to be rate-limiting. The origin of oxidative dehydrogenation over mesoporous V–TiO2 was suggested to be coordinatively unsaturated VIII species specifically activating O2 molecules. Further, a poisoning effect of product water was demonstrated to block the active V sites. UV light illumination was found to be effective to re-activate the mesoporous V–TiO2 catalyst.
Reaction Mechanisms of IO Radical Formation from the Reaction of CH3I with Cl Atom in the Presence of O2
Authors: Enami Shinichi , Sakamoto Yosuke , Yamanaka Takashi , Hashimoto Satoshi , Kawasaki Masahiro , Tonokura Kenichi , Tachikawa Hiroto 
Published: October 2008

Abstract
The yields of IO radical from the reaction of CH3I with Cl atom in the presence of O2 were determined as functions of total pressure from 5 to 250 Torr of N2 diluent and temperature over the range of 278 to 328 K using cavity ring-down spectroscopy. The yields are pressure and temperature dependent. The rate constants and product branching ratios of the reaction of CH2I radical with O2 were investigated. We determined a rate constant of (1.28±0.22)×10−12 cm3 molecule−1 s−1 at 298 K (2σ uncertainty) for this reaction. Theoretical calculations were performed to determine energetics of the reactions of CH2I + O2 and CH2Br + O2. The present results suggest that non-negligible IO radicals will be formed from the reactions of CH3I/CH2I2 + OH/Cl/NO3 at atmospheric conditions.
A Theoretical Insight into the Interaction of Fatty Acids Involved in Royal Jelly with the Human Estrogen Receptor β
Authors: Matsubara Toshiaki , Sugimoto Hiroyuki , Aida Misako 
Published: October 2008

Abstract
It has been well-known that fatty acids occurring in the royal jelly of honeybees are effective towards autonomic imbalance, perimenopausal symptoms, osteoporosis, and other conditions. These pharmacological effects of royal jelly similar to those caused by the hormone estrogen are thought to appear due to the interaction of the fatty acids of royal jelly with an estrogen receptor inside the human body. Although the structure of several major fatty acids present in royal jelly has been determined experimentally, no direct evidence of the interaction of these fatty acids with the estrogen receptor have been reported yet. In this study, we therefore give an insight into the interaction of fatty acids with the human estrogen receptor β by quantum mechanical (QM), ONIOM, and molecular dynamics (MD) methods using a model active site.
Monte Carlo Simulations of a Recent Kinetics Mechanism for the Reduction Reaction of NO by CO on Percolation Clusters
Authors: Cortés Joaquín , Valencia Eliana 
Published: October 2008

Abstract
The behavior of a recent kinetics mechanism for the reduction reaction of NO by CO on the surface of a series of percolation clusters is studied by means of Monte Carlo simulations using experimental rate constant values from the literature. The structural sensitivity of the reaction is observed through the production curves and phase diagrams. The kinetics phase transitions and the relation between production and the mean number of nearest neighbors of the cluster’s active site, the temperature and the pressure of the gas-phase components are analyzed.
Solvent-Mediated Phase Transformation from J-aggregates of Thiacarbocyanine to H-aggregates
Authors: Kitahama Yasutaka , Takazawa Ken 
Published: October 2008

Abstract
It has been found that the J-aggregates of thiacarbocyanine self-assembled in solution spontaneously transform into H-aggregates. The transformation mechanism was found to be solvent-mediated phase transformation that proceeds through dissolution of the J-aggregates and subsequent aggregation into H-aggregates.
Antibacterial Activity of Short Peptides Based on Pleurocidin and Their Interaction with Phospholipid Membranes
Authors: Tsuda Nobuaki , Koba Yukari , Hatakeyama Tomomitsu , Ando Setsuko , Shindo Mitsuno , Uchida Yoshiki , Aoyagi Haruhiko 
Published: October 2008

Abstract
We have studied antibacterial activities of model peptides based on Pleurocidin (Ple). In this study, to investigate the effect of the C-terminal portion of these model peptides on antibacterial activity, we synthesized several short peptides which are devoid of the C-terminal four and more amino acid residues from the corresponding model peptides and examined their biological activities and behaviors against lipid and cell membranes. Removal of the C-terminal four residues resulted in maintained antibacterial activity and reduction of hemolytic activity.
Polyoxygenated Steroids from a Formosan Soft Coral Sinularia facile
Authors: Chen Bo-Wei , Su Jui-Hsin , Dai Chang-Feng , Wu Yang-Chang , Sheu Jyh-Horng 
Published: October 2008

Abstract
Five new polyoxygenated steroids 1–5 have been isolated from a Formosan soft coral Sinularia facile. The structures of new metabolites were elucidated on the basis of extensive spectroscopic analysis and cytotoxic activity of 1–5 against the proliferation of a limited panel of cancer cell lines was measured. Metabolite 4 has been shown to exhibit weak cytotoxicity against Hep G2, Hep G3B, MDA-MB-231, and Ca9-22 cancer cell lines.
Highly Stereoselective Intramolecular Diels–Alder Reaction of Decatrienoates Activated by t-Butoxycarbonyl, Chloro, and Sulfonyl Groups at the Terminal Position
Authors: Inoue Seiichi , Yin Chunji , Kosugi Hiroko , Nabeta Atsuko , Sakai Yoko , Honda Kiyoshi , Hoshino Yujiro 
Published: October 2008

Abstract
Highly stereoselective intramolecular Diels–Alder (IMDA) reaction of decatrienoates has been achieved by using a more sterically hindered ester group, i.e., t-butoxycarbonyl, or electron-withdrawing hetero substituents, i.e., chloro and phenylsulfonyl, as terminal activating groups. A remarkable olefin isomerization of the Diels–Alder cycloadduct bearing a phenylsulfonyl group occurred upon heating it for a few hours and it was found that the isomerization can be catalyzed by Brønsted acid.
Photocatalytic Water Splitting into H2 and O2 over Titanate Pyrochlores Ln2Ti2O7 (Ln = Lanthanoid: Eu–Lu)
Authors: Higashi Masanobu , Abe Ryu , Sugihara Hideki , Domen Kazunari 
Published: October 2008

Abstract
A series of titanate pyrochlore Ln2Ti2O7 (Ln = Eu–Lu) was prepared by a polymerized complex method and evaluated as a photocatalyst for water splitting reaction. All the Ln2Ti2O7, except for Tb2Ti2O7, demonstrated evolution of H2 and O2 in a stoichiometric ratio from pure water under UV-light irradiation. The photocatalytic activities of the Ln2Ti2O7 were significantly enhanced by the addition of excess Ln (5%) in the preparation procedure. As for the Ln2Ti2O7 containing small Ln3+ (Ln = Dy–Lu), the enhanced photocatalytic activity can be explained by the suppression of impurity phase formation, rutile titanium oxide (TiO2), which formed in the stoichiometric preparation at high temperature. It was also found that the addition of excess Ln increased the surface area of these materials, which certainly contributed to the enhanced photocatalytic activity. In the case of Gd2Ti2O7, the photocatalytic activity was remarkably improved by the addition of excess Gd, in spite of the fact that no impurity phase formed even in the stoichiometric preparation. Scanning electron microscopy (SEM) and pore size distribution analysis revealed that the addition of excess amount of Gd made the Gd2Ti2O7 material porous, which is undoubtedly one of the major factors enhancing the photocatalytic activity.
Path Data in Marketing: An Integrative Framework and Prospectus for Model Building
Authors: Hui Sam K. , Fader Peter S. , Bradlow Eric T. 
Published: October 2008

Many data sets, from different and seemingly unrelated marketing domains, all involve paths—records of consumers' movements in a spatial configuration. Path data contain valuable information for marketing researchers because they describe how consumers interact with their environment and make dynamic choices. As data collection technologies improve and researchers continue to ask deeper questions about consumers' motivations and behaviors, path data sets will become more common and will play a more central role in marketing research.To guide future research in this area, we review the previous literature, propose a formal definition of a path (in a marketing context), and derive a unifying framework that allows us to classify different kinds of paths. We identify and discuss two primary dimensions (characteristics of the spatial configuration and the agent) as well as six underlying subdimensions. Based on this framework, we cover a range of important operational issues that should be taken into account as researchers begin to build formal models of path-related phenomena. We close with a brief look into the future of path-based models, and a call for researchers to address some of these emerging issues.
Reduced COX-2 Expression in Aged Mice Is Associated With Impaired Fracture Healing
Authors: Naik Amish A , Xie Chao , Zuscik Michael J , Kingsley Paul , Schwarz Edward M , Awad Hani , Guldberg Robert , Drissi Hicham , Puzas J Edward , Boyce Brendan , Zhang Xinping , O'Keefe Regis J 
Published: October 2008

Abstract
The cellular and molecular events responsible for reduced fracture healing with aging are unknown. Cyclooxygenase 2 (COX-2), the inducible regulator of prostaglandin E2 (PGE2) synthesis, is critical for normal bone repair. A femoral fracture repair model was used in mice at either 7–9 or 52–56 wk of age, and healing was evaluated by imaging, histology, and gene expression studies. Aging was associated with a decreased rate of chondrogenesis, decreased bone formation, reduced callus vascularization, delayed remodeling, and altered expression of genes involved in repair and remodeling. COX-2 expression in young mice peaked at 5 days, coinciding with the transition of mesenchymal progenitors to cartilage and the onset of expression of early cartilage markers. In situ hybridization and immunohistochemistry showed that COX-2 is expressed primarily in early cartilage precursors that co-express col-2.COX-2 expression was reduced by 75% and 65% in fractures from aged mice compared with young mice on days 5 and 7, respectively. Local administration of an EP4 agonist to the fracture repair site in aged mice enhanced the rate of chondrogenesis and bone formation to levels observed in young mice, suggesting that the expression of COX-2 during the early inflammatory phase of repair regulates critical subsequent events including chondrogenesis, bone formation, and remodeling. The findings suggest that COX-2/EP4 agonists may compensate for deficient molecular signals that result in the reduced fracture healing associated with aging.
Skeletal Cell Fate Decisions Within Periosteum and Bone Marrow During Bone Regeneration
Authors: Colnot Céline 
Published: October 2008

Abstract
Bone repair requires the mobilization of adult skeletal stem cells/progenitors to allow deposition of cartilage and bone at the injury site. These stem cells/progenitors are believed to come from multiple sources including the bone marrow and the periosteum. The goal of this study was to establish the cellular contributions of bone marrow and periosteum to bone healing in vivo and to assess the effect of the tissue environment on cell differentiation within bone marrow and periosteum. Results show that periosteal injuries heal by endochondral ossification, whereas bone marrow injuries heal by intramembranous ossification, indicating that distinct cellular responses occur within these tissues during repair. Next, lineage analyses were used to track the fate of cells derived from periosteum, bone marrow, and endosteum, a subcompartment of the bone marrow. Skeletal progenitor cells were found to be recruited locally and concurrently from periosteum and/or bone marrow/endosteum during bone repair. Periosteum and bone marrow/endosteum both gave rise to osteoblasts, whereas the periosteum was the major source of chondrocytes. Finally, results show that intrinsic and environmental signals modulate cell fate decisions within these tissues. In conclusion, this study sheds light into the origins of skeletal stem cells/progenitors during bone regeneration and indicates that periosteum, endosteum, and bone marrow contain pools of stem cells/progenitors with distinct osteogenic and chondrogenic potentials that vary with the tissue environment.
Association Between Change in BMD and Fragility Fracture in Women and Men
Authors: Berger Claudie , Langsetmo Lisa , Joseph Lawrence , Hanley David A , Davison K Shawn , Josse Robert G , Prior Jerilynn C , Kreiger Nancy , Tenenhouse Alan , Goltzman David 
Published: October 2008

Abstract
Our objective was to estimate the relationship between longitudinal change in BMD and fragility fractures. We studied 3635 women and 1417 men 50–85 yr of age in the Canadian Multicentre Osteoporosis Study who had at least two BMD measurements (lumbar spine, femoral neck, total hip, and trochanter) within the first 5 yr of the study and fragility fractures (any, main, forearm/wrist, ribs, hip) within the first 7 yr. Multiple logistic regression was used to model the relationship between baseline BMD, BMD change, and fragility fractures. We found that, among nonusers of antiresorptives, independent of baseline BMD, a decrease of 0.01 g/cm2/yr in total hip BMD was associated with an increased risk of fragility fracture with ORs of 1.15 (95% CI: 1.01; 1.32) in women and 1.34 (95% CI: 1.02; 1.78) in men. The risk of fragility fractures in subgroups such as fast losers and those with osteopenia was better estimated by models that included BMD change than by models that included baseline BMD but excluded BMD change. Although the association between baseline BMD and fragility fractures was similar in users and nonusers of antiresorptives, the association was stronger in nonusers compared with users. These results show that BMD change in both men and women is an independent risk factor for fragility fractures and also predicts fracture risk in those with osteopenia. The results suggest that BMD change should be included with other variables in a comprehensive fracture prediction model to capture its contribution to osteoporotic fracture risk.
Activation of Renin-Angiotensin System Induces Osteoporosis Independently of Hypertension
Authors: Asaba Yutaro , Ito Masako , Fumoto Toshio , Watanabe Ken , Fukuhara Ryoji , Takeshita Sunao , Nimura Yuji , Ishida Junji , Fukamizu Akiyoshi , Ikeda Kyoji 
Published: October 2008

Abstract
Hypertension and osteoporosis are two major age-related disorders; however, the underlying molecular mechanism for this comorbidity is not known. The renin-angiotensin system (RAS) plays a central role in the control of blood pressure and has been an important target of antihypertensive drugs. Using a chimeric RAS model of transgenic THM (Tsukuba hypertensive mouse) expressing both the human renin and human angiotensinogen genes, we showed in this study that activation of RAS induces high turnover osteoporosis with accelerated bone resorption. Transgenic mice that express only the human renin gene were normotensive and yet exhibited a low bone mass, suggesting that osteoporosis occurs independently of the development of hypertension per se. Ex vivo cultures showed that angiotensin II (AngII) acted on osteoblasts and not directly on osteoclast precursor cells and increased osteoclastogenesis-supporting cytokines, RANKL and vascular endothelial growth factor (VEGF), thereby stimulating the formation of osteoclasts. Knockdown of AT2 receptor inhibited the AngII activity, whereas silencing of the AT1 receptor paradoxically enhanced it, suggesting a functional interaction between the two AngII receptors on the osteoblastic cell surface. Finally, treatment of THM mice with an ACE inhibitor, enalapril, improved osteoporosis and hypertension, whereas treatment with losartan, an angiotensin receptor blockers specific for AT1, resulted in exacerbation of the low bone mass phenotype. Thus, blocking the synthesis of AngII may be an effective treatment of osteoporosis and hypertension, especially for those afflicted with both conditions.