bluuebunny/crossref_metadata_2025 huggingface dataset:
Mice with heterozygous deficiency of lipoic acid synthase have an increased sensitivity to lipopolysaccharide-induced tissue injury
Authors: Yi Xianwen , Kim Kuikwon , Yuan Weiping , Xu Longquan , Kim Hyung-Suk , Homeister Jonathon W , Key Nigel S , Maeda Nobuyo
Published: October 2008

α-Lipoic acid (1, 2-dithiolane-3-pentanoic acid; LA), synthesized in mitochondria by LA synthase (Lias), is a potent antioxidant and a cofactor for metabolic enzyme complexes. In this study, we examined the effect of genetic reduction of LA synthesis on its antioxidant and anti-inflammatory properties using a model of LPS-induced inflammation in Lias+/– mice. The increase of plasma proinflammatory cytokine, TNF-α, and NF-κB at an early phase following LPS injection was greater in Lias+/– mice compared with Lias+/+ mice. The circulating blood white blood cell (WBC) and platelet counts dropped continuously during the initial 4 h. The counts subsequently recovered partially in Lias+/+ mice, but the recovery was impaired totally in Lias+/– mice. Administration of exogenous LA normalized the recovery of WBC counts in Lias+/– mice but not platelets. Enhanced neutrophil sequestration in the livers of Lias+/– mice was associated with increased hepatocyte injury and increased gene expression of growth-related oncogene, E-selectin, and VCAM-1 in the liver and/or lung. Lias gene expression in tissues was 50% of normal expression in Lias+/– mice and reduced further by LPS treatment. Decreased Lias expression was associated with diminished hepatic LA and tissue oxidative stress. Finally, Lias+/– mice displayed enhanced mortality when exposed to LPS-induced sepsis. These data demonstrate the importance of endogenously produced LA for preventing leukocyte accumulation and tissue injury that result from LPS-induced inflammation.
11β-Hydroxysteroid Dehydrogenase Type II Inhibition Causes Cerebrovascular Remodeling and Increases Infarct Size after Cerebral Ischemia
Authors: Osmond Jessica M. , Dorrance Anne M.
Published: October 2008

Direct mineralocorticoid receptor (MR) activation with deoxycorticosterone acetate has deleterious effects on the cerebral vasculature. Inhibition of 11β-hydroxysteroid dehydrogenase type II (11βHSD2) mimics the detrimental effects of elevated mineralocorticoids in the heart, but the effect of enzyme inactivation on the cerebral vasculature is unknown. Therefore, we hypothesized that systemic 11βHSD2 inhibition with carbenoxolone (CBX) would cause remodeling of the middle cerebral artery (MCA) and increase the damage caused by cerebral ischemia. Six-week-old male Sprague Dawley rats were divided into control and CBX (2.5 mg/d) + 0.9% NaCl treated. After 4 wk treatment, rats were used to assess either structure and reactivity of the MCA or the response to cerebral ischemia using the MCA occlusion technique. Cerebral damage was assessed by 2,3,5-triphenyltetrazolium chloride staining and expressed as a percentage of the hemisphere infarcted. CBX treatment increased systolic blood pressure (153.2 ± 7.3 vs. 122.1 ± 4.4 mm Hg; P < 0.05) compared with control rats. MCAs from CBX treated rats were smaller and stiffer than control MCAs over a range of intralumenal pressures, indicating inward remodeling of the vessel. CBX treatment significantly increased ischemic cerebral infarct size compared with control rats (27.1 ± 5.4% vs. 14.8 ± 4.2%; P < 0.05). These data indicate that inhibition of 11βHSD2, and, thus, disproportionate glucocorticoid activation of the MR, results in remodeling of the MCA and worsens the outcome of cerebral ischemia, further underscoring the importance of understanding the mechanism by which MR activation leads to cerebrovascular disease.

11β-Hydroxysteroid dehydrogenase inhibition increases blood pressure, altering cerebral vessel structure in a manner that increases the damaged caused by focal cerebral ischemia in rats.
Alterations in Hypothalamic KiSS-1 System in Experimental Diabetes: Early Changes and Functional Consequences
Authors: Castellano J. M. , Navarro V. M. , Roa J. , Pineda R. , Sánchez-Garrido M. A. , García-Galiano D. , Vigo E. , Dieguez C. , Aguilar E. , Pinilla L. , Tena-Sempere M.
Published: October 2008

Using long-term streptozotocin (STZ)-treated male rats, we recently proposed that defective function of hypothalamic KiSS-1 system is mechanistically relevant for central hypogonadotropism of uncontrolled diabetes. However, the temporal pattern of such defects and its potential contribution to disturbed gonadotropin secretion in the diabetic female remain so far unexplored. To cover these issues, expression analyses and hormonal tests were conducted in diabetic male (1 wk after STZ; short term) and female (4 wk after STZ; long term) rats. Short-term diabetic males had lower basal testosterone levels and decreased gonadotropin responses to orchidectomy (ORX), which associated with significantly attenuated post-ORX rises of hypothalamic KiSS-1 mRNA. Yet kisspeptin administration to diabetic males was able to acutely elicit supramaximal LH and testosterone responses and normalize post-ORX gonadotropin secretion. Long-term diabetic females showed persistent anestrus and significantly decreased basal gonadotropin levels as well as blunted LH responses to ovariectomy; changes that were linked to lowering of basal and postovariectomy expression of hypothalamic KiSS-1 mRNA. Moreover, despite prevailing gonadotropin suppression, LH responses to acute kisspeptin administration were fully preserved, and even enhanced after its repeated injection, in diabetic females. In sum, our present findings further define the temporal course and mechanistic relevance of altered hypothalamic KiSS-1 system in the hypogonadotropic state of uncontrolled diabetes. Furthermore, our data provide the basis for the potential therapeutic intervention of the KiSS-1 system as adjuvant in the management of disturbed gonadotropin secretion of type 1 diabetes in the female.

The time-course and functional consequences of disturbances of the hypothalamic Kisspeptin-1-system in a rat model of uncontrolled diabetes are reviewed, with findings of potential physiopathologic and therapeutic implications for impaired fertility in type 1 diabetes.
Presence, Actions, and Regulation of Myostatin in Rat Uterus and Myometrial Cells
Authors: Ciarmela Pasquapina , Wiater Ezra , Smith Sean M. , Vale Wylie
Published: October 2008

Myostatin, a member of the TGF-β superfamily of proteins, is known to suppress skeletal muscle mass and myocyte proliferation. The muscular component of the uterus is the myometrium, a tissue that regulates its mass in response to different physiological conditions under the influence of sex steroids. Recently, our laboratory reported effects of activin-A, another TGF-β family member, on signalling and proliferation of rat uterine explants and human myometrial cell lines in culture. Here, we explore the expression, actions, and regulation of myostatin in uterine smooth muscle. Myostatin mRNA was demonstrated to be expressed in a myometrial cell line, pregnant human myometrial 1 cell line (PHM1). Functional assays showed that myostatin induced phosphorylation of Smad-2 and reduced proliferation of PHM1 number in a time and dose-dependent manner. Furthermore, myostatin activated smad-2 specific signalling pathways in rat uterine explants. To expand on our in vitro findings, we found that myostatin is expressed in rat uterus and determined that myostatin mRNA expression varies as a function of the phase of the estrous cycle. Uterine levels of myostatin peaked during late estrus and were the lowest at proestrus. Ovariectomy increased myostatin expression; estrogen treatment strongly decreased myostatin levels, whereas progesterone weakly decreased myostatin expression. In conclusion, myometrial cells are myostatin sensitive, myostatin mRNA levels are modulated in vivo in rats during the estrous cycle, and in response to steroid deprivation and replacement.

Myometrial cells are myostatin-sensitive; myostatin mRNA levels are modulated in rats during the estrous cycle and in response to steroid deprivation and replacement.
Glucagon-Like Peptide-2 Reduces Intestinal Permeability But Does Not Modify the Onset of Type 1 Diabetes in the Nonobese Diabetic Mouse
Authors: Hadjiyanni Irene , Li Kunmin Karen , Drucker Daniel J.
Published: October 2008

The development of type 1 diabetes (T1D) has been linked to environmental factors and dietary components. Increasing evidence indicates that the integrity of the gut mucosa plays a role in the development of autoimmune diseases, and evidence from both preclinical and clinical studies demonstrates that increased leakiness of the intestinal epithelium precedes the development of type 1 diabetes. However, there is limited information on modulation of gut barrier function and its relationship to diabetes development. Here we show that the nonobese diabetic (NOD) mouse, a model of T1D, exhibits enhanced intestinal transcellular permeability before the development of autoimmune diabetes. Treatment of NOD mice with a glucagon-like peptide 2 (GLP-2) analog, synthetic human [Gly2] glucagon-like peptide-2 (h[Gly2]GLP-2, increased the length and weight of the small bowel and significantly improved jejunal transepithelial resistance. However, chronic administration of once daily h[Gly2]GLP-2 failed to delay or reverse the onset of T1D when treatment was initiated in young, normoglycemic female NOD mice. Furthermore, h[Gly2]GLP-2 administration had no significant effect on lymphocyte subpopulations in NOD mice. These findings demonstrate that h[Gly2]GLP-2-mediated enhancement of gut barrier function in normoglycemic NOD mice disease is not sufficient to prevent or delay the development of experimental T1D.

Increased intestinal permeability often precedes the clinical appearance of autoimmune disorders such as celiac disease or type 1 diabetes. These studies show that glucagon-like peptide 2 reduces gut permeability, but not the onset of diabetes in NOD mice.
Commentary: Introduction to The Year in Basic Science Series
Authors: Shupnik Margaret A.
Published: October 2008

This year, in response to member input and suggestions to highlight the vibrant basic science of endocrinology, The Endocrine Society Annual Meeting (ENDO 08) introduced a new feature, The Year in Basic Science series. Among the many interests and strengths of our members, three broad areas were chosen for initial consideration: nuclear receptors, kinase signaling, and hormones and cancer. Speakers were invited to present and discuss important publications during the past year between annual meetings (roughly June to June), and to put these findings into broad perspective for the endocrine community. Three distinguished researchers, Bert O'Malley, Tony Means, and Kate Horwitz, graciously agreed to participate in the inaugural venture, and this series of articles is based on their presentations at ENDO 08. Each individual approached this somewhat daunting task slightly differently. However, all three observed important and often common themes that ultimately link current basic molecular findings to broad translational and clinical problems, including metabolism and energy balance, neuronal migration and synapse formation, long-term memory formation, and endocrine pathology in cancer, reproduction and osteoporosis.
Chromatin and the cell cycle meet in Madrid
Authors: Dominguez Maria , Berger Frédéric
Published: October 2008

At the end of June 2008, researchers from diverse fields, ranging from chromatin remodeling to cell cycle control, gathered in Madrid at a Cantoblanco Workshop entitled `Chromatin at the Nexus of Cell Division and Differentiation'. The work discussed at this meeting, which was co-organized by Crisanto Gutierrez, Ben Scheres and Ueli Grossniklaus, highlighted the emerging connections that exist between cell cycle regulation and chromatin in both animals and plants.
Temporal control of neuronal diversity: common regulatory principles in insects and vertebrates?
Authors: Jacob John , Maurange Cédric , Gould Alex P.
Published: October 2008

It is well established in species as diverse as insects and mammals that different neuronal and glial subtypes are born at distinct times during central nervous system development. In Drosophila, there is now compelling evidence that individual multipotent neuroblasts express a sequence of progenitor transcription factors which, in turn, regulates the postmitotic transcription factors that specify neuronal/glial temporal identities. Here,we examine the hypothesis that the regulatory principles underlying this mode of temporal specification are shared between insects and mammals, even if some of the factors themselves are not. We also propose a general model for birth-order-dependent neural specification and suggest some experiments to test its validity.
Hedgehog signaling plays a cell-autonomous role in maximizing cardiac developmental potential
Authors: Thomas Natalie A. , Koudijs Marco , van Eeden Fredericus J. M. , Joyner Alexandra L. , Yelon Deborah
Published: October 2008

Elucidation of the complete roster of signals required for myocardial specification is crucial to the future of cardiac regenerative medicine. Prior studies have implicated the Hedgehog (Hh) signaling pathway in the regulation of multiple aspects of heart development. However, our understanding of the contribution of Hh signaling to the initial specification of myocardial progenitor cells remains incomplete. Here, we show that Hh signaling promotes cardiomyocyte formation in zebrafish. Reduced Hh signaling creates a cardiomyocyte deficit, and increased Hh signaling creates a surplus. Through fate-mapping, we find that Hh signaling is required at early stages to ensure specification of the proper number of myocardial progenitors. Genetic inducible fate mapping in mouse indicates that myocardial progenitors respond directly to Hh signals, and transplantation experiments in zebrafish demonstrate that Hh signaling acts cell autonomously to promote the contribution of cells to the myocardium. Thus, Hh signaling plays an essential early role in defining the optimal number of cardiomyocytes, making it an attractive target for manipulation of multipotent progenitor cells.
Mobilisation of Ca2+ stores and flagellar regulation in human sperm by S-nitrosylation: a role for NO synthesised in the female reproductive tract
Authors: Machado-Oliveira Gisela , Lefièvre Linda , Ford Christopher , Herrero M. Belen , Barratt Christopher , Connolly Thomas J. , Nash Katherine , Morales-Garcia Aduen , Kirkman-Brown Jackson , Publicover Steve
Published: October 2008

Generation of NO by nitric oxide synthase (NOS) is implicated in gamete interaction and fertilisation. Exposure of human spermatozoa to NO donors caused mobilisation of stored Ca2+ by a mechanism that did not require activation of guanylate cyclase but was mimicked by S-nitroso-glutathione (GSNO; an S-nitrosylating agent). Application of dithiothreitol, to reduce protein -SNO groups, rapidly reversed the actions of NO and GSNO on [Ca2+]i. The effects of NO, GSNO and dithiothreitol on sperm protein S-nitrosylation, assessed using the biotin switch method, closely paralleled their actions on[Ca2+]i. Immunofluorescent staining revealed constitutive and inducible NOS in human oviduct and cumulus (the cellular layer investing the oocyte). 4,5-diaminofluorescein (DAF) staining demonstrated production of NO by these tissues. Incubation of human sperm with oviduct explants induced sperm protein S-nitrosylation resembling that induced by NO donors and GSNO. Progesterone (a product of cumulus cells) also mobilises stored Ca2+ in human sperm. Pre-treatment of sperm with NO greatly enhanced the effect of progesterone on[Ca2+]i, resulting in a prolonged increase in flagellar excursion. We conclude that NO regulates mobilisation of stored Ca2+ in human sperm by protein S-nitrosylation, that this action is synergistic with that of progesterone and that this synergism is potentially highly significant in gamete interactions leading to fertilisation.
The endosperm-specificZHOUPIgene ofArabidopsis thalianaregulates endosperm breakdown and embryonic epidermal development
Authors: Yang Suxin , Johnston Niamh , Talideh Edmund , Mitchell Steve , Jeffree Chris , Goodrich Justin , Ingram Gwyneth
Published: October 2008

During Arabidopsis seed development, the growing embryo invades and consumes the surrounding endosperm tissue. The signalling pathways that coordinate the separation of the embryo from the endosperm and the concomitant breakdown of the endosperm are poorly understood. We have identified a novel bHLH transcription factor, ZHOUPI (ZOU), which mediates these processes. ZOU is expressed exclusively in the endosperm of developing seeds. It is activated in the central cell immediately after fertilization and is initially expressed uniformly in endosperm, subsequently resolving to the embryo surrounding region (ESR). However, zou mutant embryos have defects in cuticle formation and in epidermal cell adhesion,suggesting that ZOU functions non-autonomously to regulate embryonic development. In addition, the endosperm of zou mutant seeds fails to separate from the embryo, restricting embryo expansion and resulting in the production of shrivelled collapsed seeds. zou seeds retain more endosperm than do wild-type seeds at maturity, suggesting that ZOUalso controls endosperm breakdown. We identify several target genes whose expression in the ESR is regulated by ZOU. These include ABNORMAL LEAF SHAPE1, which encodes a subtilisin-like protease previously shown to have a similar role to ZOU in regulating endosperm adhesion and embryonic epidermal development. However, expression of several other ESR-specific genes is independent of ZOU. Therefore, ZOU is not a general regulator of endosperm patterning, but rather controls specific signalling pathways that coordinate embryo invasion and breakdown of surrounding endosperm tissues.
MEX-5 asymmetry in one-cellC. elegansembryos requires PAR-4-and PAR-1-dependent phosphorylation
Authors: Tenlen Jennifer R. , Molk Jeffrey N. , London Nitobe , Page Barbara D. , Priess James R.
Published: October 2008

Anteroposterior polarity in early C. elegans embryos is required for the specification of somatic and germline lineages, and is initiated by a sperm-induced reorganization of the cortical cytoskeleton and PAR polarity proteins. Through mechanisms that are not understood, the kinases PAR-1 and PAR-4, and other PAR proteins cause the cytoplasmic zinc finger protein MEX-5 to accumulate asymmetrically in the anterior half of the one-cell embryo. We show that MEX-5 asymmetry requires neither vectorial transport to the anterior, nor protein degradation in the posterior. MEX-5 has a restricted mobility before fertilization and in the anterior of one-cell embryos. However, MEX-5 mobility in the posterior increases as asymmetry develops,presumably allowing accumulation in the anterior. The MEX-5 zinc fingers and a small, C-terminal domain are essential for asymmetry; the zinc fingers restrict MEX-5 mobility, and the C-terminal domain is required for the increase in posterior mobility. We show that a crucial residue in the C-terminus, Ser 458, is phosphorylated in vivo. PAR-1 and PAR-4 kinase activities are required for the phosphorylation of S458, providing a link between PAR polarity proteins and the cytoplasmic asymmetry of MEX-5.
The Wnt signaling regulator R-spondin 3 promotes angioblast and vascular development
Authors: Kazanskaya Olga , Ohkawara Bisei , Heroult Melanie , Wu Wei , Maltry Nicole , Augustin Hellmut G. , Niehrs Christof
Published: October 2008

The vertebrate embryonic vasculature develops from angioblasts, which are specified from mesodermal precursors and develop in close association with blood cells. The signals that regulate embryonic vasculogenesis and angiogenesis are incompletely understood. Here, we show that R-spondin 3(Rspo3), a member of a novel family of secreted proteins in vertebrates that activate Wnt/β-catenin signaling, plays a key role in these processes. In Xenopus embryos, morpholino antisense knockdown of Rspo3 induces vascular defects because Rspo3 is essential for regulating the balance between angioblast and blood cell specification. In mice, targeted disruption of Rspo3 leads to embryonic lethality caused by vascular defects. Specifically in the placenta, remodeling of the vascular plexus is impaired. In human endothelial cells, R-spondin signaling promotes proliferation and sprouting angiogenesis in vitro, indicating that Rspo3 can regulate endothelial cells directly. We show that vascular endothelial growth factor is an immediate early response gene and a mediator of R-spondin signaling. The results identify Rspo3 as a novel, evolutionarily conserved angiogenic factor in embryogenesis.
Friction-driven vibro-impact system for percussive-rotary drilling: A numerical study of the system dynamics
Authors: Batako A D L , Piiroinen P T
Published: October 2008

Stick—slip-induced vibration in drilling has a detrimental effect on the drilling system and may lead to the failure of the drill string. This study is a further development of a friction-driven vibro-impact system which was investigated previously. The system used the stick—slip properties to generate a vibratory motion of a hammer that collides with the bit. The previous study focused on the influence of the friction on the response of the system without impacts. This paper investigates the full dynamic response of the model including friction and impact. Numerical bifurcation analysis of the system is undertaken to establish various motions and dynamical changes. This study focuses on the system performance outside the stable interval identified in the earlier investigation. The response of the system is illustrated along with the phase portraits.
Synthesis of snubber's spectral characteristics for vibration protection of sensitive components in airborne gyrostabilized electro-optic payloads
Authors: Veprik A , Djerassy S , Babitsky V
Published: October 2008

Low-frequency vibration isolation of airborne gyrostabilized electro-optic payloads is the ultimate and proven solution aimed at improving their imagery performance, primarily during a quiet cruise flight. This portion of the airborne mission is characterized by rather moderate environmental conditions, under which vibration mounts operate in a linear working range within the predefined working rattle space, which eventually results in better performances. Compliant snubbers are indispensable emergency components in such vibration protection arrangements primarily needed during exposure to the extreme environmental conditions typical of the relatively short periods of airborne missions such as take-off, landing, weapon application, etc. Their primary objective is to protect these soft vibration mounts and prevent their bottoming and disintegration without any impulsive accelerations that compromise the integrity of the payload frame and fragile internal components mounted upon it. The optimal approach for designing a snubbed vibration isolator, delivering a fail-safe environment for both the payload frame and critical components subjected to tight constraints imposed on the size, weight, and price does not seem to exist. It is intended to devise the optimal design approach and to demonstrate its application on low-frequency vibration mounted electro-optic payload comprising the vibration sensitive integrated dewar-detector-cooler assembly.
Probabilistic design of discrete-time guaranteed cost regulators
Authors: Fujisaki Y , Kitajima Y , Oishi Y
Published: October 2008

A guaranteed cost regulator design is presented for uncertain linear discrete-time systems, where its objective is to find a state feedback such that a quadratic performance index is less than a given value for any uncertainty. The design is recast as a feasibility problem described by a parametrized linear matrix inequality (LMI). A notion of probabilistic solution that satisfies the LMI for almost all uncertainties is introduced and an efficient randomized algorithm based on the gradient method with random samples of the uncertainty is developed. The proposed algorithm always stops in a finite number of iterations. Then, it can either find a probabilistic solution with a given probabilistic confidence or detect the infeasibility of the problem in the sense that the feasibility set is too small to contain a ball with a given radius.
Pattern discrimination method with a boosting approach using hierarchical neural trees
Authors: Okamoto M , Shima K , Matsubara Y , Tsuji T
Published: October 2008

This paper proposes a new pattern classification method using probabilistic neural networks based on a boosting approach. In this method, a log-linearized Gaussian mixture network is used as a weak classifier. The method proposed automatically constructs a suitable classification network from given data. Validity of the proposed method is shown by discrimination results of artificial data and hand shape. The application is confirmed of the proposed method to human interface controlling of home electric appliances using hand shapes.
Shaping of molecular weight distribution by iterative learning probability density function control strategies
Authors: Yue H , Wang H , Zhang J
Published: October 2008

A mathematical model is developed for the molecular weight distribution (MWD) of free-radical styrene polymerization in a simulated semi-batch reactor system. The generation function technique and moment method are employed to establish the MWD model in the form of Schultz—Zimm distribution. Both static and dynamic models are described in detail. In order to achieve the closed-loop MWD shaping by output probability density function (PDF) control, the dynamic MWD model is further developed by a linear B-spline approximation. Based on the general form of the B-spline MWD model, iterative learning PDF control strategies have been investigated in order to improve the MWD control performance. Discussions on the simulation studies show the advantages and limitations of the methodology.
Heterogeneous Asymmetric Catalysis in Water with Amphiphilic Polymer-Supported Homochiral Palladium Complexes
Authors: Uozumi Yasuhiro
Published: October 2008

Heterogeneous aquacatalytic highly selective organic transformations are what may be considered ideal chemical processes of the next generation, where the advantages of both aqueous- and heterogeneous-switching are combined in one system to meet green sustainable chemical requirements. Heterogeneous aquacatalytic asymmetric reactions were achieved with palladium complexes of homochiral phosphine ligands which were immobilized onto amphiphilic polystyrene–poly(ethylene glycol) (PS–PEG) resin beads via chemical bonding. The catalyst was recovered by simple filtration and was reused without any loss of catalytic activity and stereoselectivity. In particular, a novel chiral P,N-ligand, (3R,9aS)-2-aryl-3-[2-(diphenylphosphino)phenyl]tetrahydro-1H-imidazo[1,5-a]indole-1-one, was designed and prepared on PS–PEG to realize palladium-catalyzed π-allylic substitution of both cyclic and acyclic substrates with carbon, nitrogen, and oxygen nucleophiles in water with enantioselectivity of up to 99% ee.
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

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

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 < monoprotonated ferrate < 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

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

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

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

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

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

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

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

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

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

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

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.
Research Note—The Traveling Salesman Goes Shopping: The Systematic Deviations of Grocery Paths from TSP Optimality
Authors: Hui Sam K. , Fader Peter S. , Bradlow Eric T.
Published: October 2008

We examine grocery shopping paths using the traveling salesman problem (TSP) as a normative frame of reference. We define the TSP-path for each shopper as the shortest path that connects all of his purchases. We then decompose the length of each observed path into three components: the length of the TSP-path, the additional distance because of order deviation (i.e., not following the TSP-order of category purchases), and the additional distance because of travel deviation (i.e., not following the shortest point-to-point route). We explore the relationship between these deviations and different aspects of in-store shopping/purchase behavior. Among other things, our results suggest that (1) a large proportion of trip length is because of travel deviation; (2) paths that deviate substantially from the TSP solution are associated with larger shopping baskets; (3) order deviation is strongly associated with purchase behavior, while travel deviation is not; and (4) shoppers with paths closer to the TSP solution tend to buy more from frequently purchased product categories.
Why Pseudonyms? Deception as Identity Preservation Among Jazz Record Companies, 1920–1929
Authors: Phillips Damon J. , Kim Young-Kyu
Published: October 2008

This paper theoretically and empirically engages the relationship between organizational identity and deception using the market for early jazz recordings as a setting. In this setting, pseudonyms (where a recording is reissued under a fictitious name) were used deceptively as a way to preserve a firm's identity while selling profitable but identity-threatening products to the mass market. Firms founded in the Victorian Era actively sought alignment with the cultural elite and used pseudonyms to deceive observers into believing that their production of cultural products was consistent with their Victorian Era identity. In effect, pseudonyms allowed these firms to decouple their position in identity space from their position in product space by inflating production of identity-preserving products. Using product data from jazz discographies, record company directories, and record advertisements in major U.S. newspapers, we provide strong empirical evidence that Victorian Era firms were active in using pseudonyms to preserve their identities.
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

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.