bluuebunny/crossref_metadata_2025 huggingface dataset:
Expression of G Protein-Coupled Receptor-30, a G Protein-Coupled Membrane Estrogen Receptor, in Oxytocin Neurons of the Rat Paraventricular and Supraoptic Nuclei
Authors: Sakamoto Hirotaka , Matsuda Ken-ichi , Hosokawa Koji , Nishi Mayumi , Morris John F. , Prossnitz Eric R. , Kawata Mitsuhiro
Published: September 2007

The regulatory actions of estrogens on magnocellular oxytocin (OT) neurons of the paraventricular and supraoptic nuclei are well documented. Although the expression and distribution of nuclear estrogen receptor-β, but not estrogen receptor-α, in the OT neuron has been described, the nuclear receptors may not explain all aspects of estrogen function in the hypothalamic OT neuron. Recently a G protein-coupled receptor (GPR) for estrogens, GPR30, has been identified as a membrane-localized estrogen receptor in several cancer cell lines. In this study, we therefore investigated the expression and localization of GPR30 in magnocellular OT neurons to understand the mode of rapid estrogen actions within these neurons. Here we show that, in the paraventricular nucleus and supraoptic nucleus, GPR30 is expressed in magnocellular OT neurons at both mRNA and protein levels but is not expressed in vasopressin neurons. Specific markers for intracellular organelles and immunoelectron microscopy revealed that GPR30 was localized mainly in the Golgi apparatus of the neurons but could not be detected at the cell surface. In addition, the expression of GPR30 is also detected in the neurohypophysis. These results suggest that GPR30 may serve primarily as a nongenomic transducer of estrogen actions in the hypothalamo-neurohypophyseal system.
Age-Related Alterations in Pituitary and Testicular Functions in Long-Lived Growth Hormone Receptor Gene-Disrupted Mice
Authors: Chandrashekar Varadaraj , Dawson Christina R. , Martin Eric R. , Rocha Juliana S. , Bartke Andrzej , Kopchick John J.
Published: September 2007

The somatotropic axis, GH, and IGF-I interact with the hypothalamic-pituitary-gonadal axis in health and disease. GH-resistant GH receptor-disrupted knockout (GHRKO) male mice are fertile but exhibit delayed puberty and decreases in plasma FSH levels, testicular content of LH, and prolactin (PRL) receptors, whereas PRL levels are elevated. Because the lifespan of GHRKO mice is much greater than the lifespan of their normal siblings, it was of interest to compare age-related changes in the hypothalamic-pituitary-gonadal axis in GHRKO and normal animals. Plasma IGF-I, insulin, PRL, LH, FSH, androstenedione and testosterone levels, and acute responses to GnRH and LH were measured in young (2–4 and 5–6 months of age) and old (18–19 and 23–26 months of age) male GHRKO mice and their normal siblings. Plasma IGF-I was not detectable in GHRKO mice. Plasma PRL levels increased with age in normal mice but declined in GHRKO males, and did not differ in old GHRKO and normal animals. Plasma LH responses to acute GnRH stimulation were attenuated in GHRKO mice but increased with age only in normal mice. Plasma FSH levels were decreased in GHRKO mice regardless of age. Plasma testosterone responses to LH stimulation were attenuated in old mice regardless of genotype, whereas plasma androstenedione responses were reduced with age only in GHRKO mice. Testicular IGF-I mRNA levels were normal in young and increased in old GHRKO mice, whereas testicular concentrations and total IGF-I levels were decreased in these animals. These findings indicate that GH resistance due to targeted disruption of the GH receptor gene in mice leads to suppression of testicular IGF-I levels, and modifies the effects of aging on plasma PRL levels and responses of the pituitary and testes to GnRH and LH stimulation. Plasma testosterone levels declined during aging in normal but not in GHRKO mice, and the age-related increase in the LH responses to exogenous GnRH was absent in GHRKO mice, perhaps reflecting a delay of aging in these remarkably long-lived animals.
27-Hydroxycholesterol Is an Endogenous Selective Estrogen Receptor Modulator
Authors: DuSell Carolyn D. , Umetani Michihisa , Shaul Philip W. , Mangelsdorf David J. , McDonnell Donald P.
Published: September 2007

Selective estrogen receptor (ER) modulators (SERMs) are ER ligands whose relative agonist/antagonist activities vary in a cell- and promoter-dependent manner. The molecular basis underlying this selectivity can be attributed to the ability of these ligands to induce distinct alterations in ER structure leading to differential recruitment of coactivators and corepressors. Whether SERM activity is restricted to synthetic ligands or whether molecules exist in vivo that function in an analogous manner remains unresolved. However, the recent observation that oxysterols bind ER and antagonize the actions of 17β-estradiol (E2) on the vascular wall suggests that this class of ligands may possess SERM activity. We demonstrate here that 27-hydroxycholesterol (27HC), the most prevalent oxysterol in circulation, functions as a SERM, the efficacy of which varies when assessed on different endpoints. Importantly, 27HC positively regulates both gene transcription and cell proliferation in cellular models of breast cancer. Using combinatorial peptide phage display, we have determined that 27HC induces a unique conformational change in both ERα and ERβ, distinguishing it from E2 and other SERMs. Thus, as with other ER ligands, it appears that the unique pharmacological activity of 27HC relates to its ability to impact ER structure and modulate cofactor recruitment. Cumulatively, these data indicate that 27HC is an endogenous SERM with partial agonist activity in breast cancer cells and suggest that it may influence the pathology of breast cancer. Moreover, given the product-precursor relationship between 27HC and cholesterol, our findings have implications with respect to breast cancer risk in obese/hypercholesteremic individuals.
American Health Policy: Cracks in the Foundation
Authors: Nyman John A.
Published: September 2007

Much American health policy over the past thirty-five years has focused on reducing the additional health care that is consumed when a person becomes insured, that is, reducing moral hazard. According to conventional theory, all of moral hazard represents a welfare loss to society because its cost exceeds its value. Empirical support for this theory has been provided by the RAND Health Insurance Experiment, which found that moral hazard—even moral hazard in the form of effective and appropriate hospital procedures—could be reduced substantially using cost-sharing policies with little or no measurable effect on health.

This article critically analyzes these two cornerstones of American health policy. It holds that a large portion of moral hazard actually represents health care that ill consumers would not otherwise have access to without the income that is transferred to them through insurance. This portion of moral hazard is efficient and generates a welfare gain. Further, it holds that the RAND experiment's finding (that health care could be reduced substantially with little or no effect on health) may actually be caused by the large number of participants who voluntarily dropped out of the cost-sharing arms of the experiment. Indeed, almost all of the reduction in hospital use in the cost-sharing plans could be attributed to this voluntary attrition. If so, the RAND finding that cost sharing could reduce health care utilization, especially utilization in the form of effective and appropriate hospital procedures, with no appreciable effect on health is spurious.

The article concludes by observing that the preoccupation with moral hazard is misplaced and has worked to obscure policies that would better reduce health care expenditures. It has also led us away from policies that would extend insurance coverage to the uninsured.
The Impact of the Adoption of Gag Laws on Trust in the Patient-Physician Relationship
Authors: Patel Mitesh S. , Chernew Michael E.
Published: September 2007

Physician organizations, policy makers, and patient advocates have expressed concern that health plans have contractually limited the freedom of physicians to communicate with their patients. In response, many states have adopted gag laws that limit the ability of managed care contracts to restrict patient-physician communication. We examine the impact of these laws on patient trust in the physician.

We analyzed patients' ratings of trust in their physicians in states before and after adoption of gag laws. Individuals in states that had such laws throughout the study period were used as the comparison group. The analysis is based on a nationally representative sample of adults obtained from the 1996-1997 and 1998-1999 Community Tracking Study Household Surveys.

After adjustment for patient characteristics, it was estimated that the adoption of gag laws had no statistically significant impact on trust in the physician for the average patient. However, the adoption of gag laws is estimated to have increased trust in the physician by a modest amount (25 percent of a standard deviation) for health maintenance organization (HMO) enrollees who did not have a usual source of care.

Gag laws may assure HMO enrollees without a usual source of care that their physicians are free to speak candidly about treatment options. This does not necessarily imply that physicians are prohibited from speaking freely in the absence of such laws, but gag laws indicate concerns (justified or not) that patients have about unrestricted communication with their health care providers.
Sanctions and Recidivism: An Evaluation of Physician Discipline by State Medical Boards
Authors: Grant Darren , Alfred Kelly C.
Published: September 2007

This article descriptively assesses how physicians are disciplined by state medical boards throughout the United States, drawing on a nationwide database of sanctions delivered during the period 1994-2002. We identify the frequency and severity of disciplinary actions, the offenses leading to actions, and the degree to which sanctioned physicians are subsequently sanctioned again in the future. The most significant finding is that there are a very large number of repeat offenders among physicians who have received board sanctions, indicating a possible need for greater monitoring of disciplined physicians or less reliance upon rehabilitative sanctions.
Fgf3is required for dorsal patterning and morphogenesis of the inner ear epithelium
Authors: Hatch Ekaterina P. , Noyes C. Albert , Wang Xiaofen , Wright Tracy J. , Mansour Suzanne L.
Published: September 2007

The inner ear, which contains sensory organs specialized for hearing and balance, develops from an ectodermal placode that invaginates lateral to hindbrain rhombomeres (r) 5-6 to form the otic vesicle. Under the influence of signals from intra- and extraotic sources, the vesicle is molecularly patterned and undergoes morphogenesis and cell-type differentiation to acquire its distinct functional compartments. We show in mouse that Fgf3,which is expressed in the hindbrain from otic induction through endolymphatic duct outgrowth, and in the prospective neurosensory domain of the otic epithelium as morphogenesis initiates, is required for both auditory and vestibular function. We provide new morphologic data on otic dysmorphogenesis in Fgf3 mutants, which show a range of malformations similar to those of Mafb (Kreisler), Hoxa1 and Gbx2mutants, the most common phenotype being failure of endolymphatic duct and common crus formation, accompanied by epithelial dilatation and reduced cochlear coiling. The malformations have close parallels with those seen in hearing-impaired patients. The morphologic data, together with an analysis of changes in the molecular patterning of Fgf3 mutant otic vesicles, and comparisons with other mutations affecting otic morphogenesis, allow placement of Fgf3 between hindbrain-expressed Hoxa1 and Mafb,and otic vesicle-expressed Gbx2, in the genetic cascade initiated by WNT signaling that leads to dorsal otic patterning and endolymphatic duct formation. Finally, we show that Fgf3 prevents ventral expansion of r5-6 neurectodermal Wnt3a, serving to focus inductive WNT signals on the dorsal otic vesicle and highlighting a new example of cross-talk between the two signaling systems.
Cis-regulatory analysis ofnodaland maternal control of dorsal-ventral axis formation by Univin, a TGF-β related to Vg1
Authors: Range Ryan , Lapraz François , Quirin Magali , Marro Sophie , Besnardeau Lydia , Lepage Thierry
Published: September 2007

The TGF-β family member Nodal is essential for specification of the dorsal-ventral axis of the sea urchin embryo, but the molecular factors regulating its expression are not known. Analysis of the nodalpromoter is an excellent entry point to identify these factors and to dissect the regulatory logic driving dorsal-ventral axis specification. Using phylogenetic footprinting, we delineated two regulatory regions located in the 5′ region of the nodal promoter and in the intron that are required for correct spatial expression and for autoregulation. The 5′regulatory region contains essential binding sites for homeodomain, bZIP, Oct,Tcf/Lef, Sox and Smad transcription factors, and a binding site for an unidentified spatial repressor possibly related to Myb. Soon after its initiation, nodal expression critically requires autoregulation by Nodal and signaling by the maternal TGF-β Univin. We show that Univin is related to Vg1, that both Nodal and Univin signal through Alk4/5/7, and that zygotic expression of univin, like that of nodal, is dependent on SoxB1 function and Tcf/β-catenin signaling. This work shows that Tcf, SoxB1 and Univin play essential roles in the regulation of nodal expression in the sea urchin and suggests that some of the regulatory interactions controlling nodal expression predate the chordates. The data are consistent with a model of nodal regulation in which a maternal TGF-β acts in synergy with maternal transcription factors and with spatial repressors to establish the dorsal-ventral axis of the sea urchin embryo.
TheHECATEgenes regulate female reproductive tract development inArabidopsis thaliana
Authors: Gremski Kristina , Ditta Gary , Yanofsky Martin F.
Published: September 2007

Successful fertilization in plants requires the properly coordinated development of female reproductive tissues, including stigma, style, septum and transmitting tract. We have identified three closely related genes, HECATE1 (HEC1), HECATE2 (HEC2) and HECATE3 (HEC3), the expression domains of which encompass these regions of the Arabidopsis gynoecium. The HEC genes encode putative basic helix-loop-helix (bHLH) transcription factors with overlapping functionality. Depending on the amount of HEC function missing, plants exhibit varying degrees of infertility, defects in septum,transmitting tract and stigma development and impaired pollen tube growth. The observed phenotypes are similar to those reported for mutations in the SPATULA (SPT) gene, which also encodes a bHLH transcription factor required for development of the same female tissues. We show that the HEC proteins can dimerize with SPT in a yeast two-hybrid system, indicating that the HEC genes work in concert with SPT to coordinately regulate development of the female reproductive tract. Furthermore, when the HEC genes are ectopically expressed from the CaMV 35S promoter, some of the resulting transgenic plants show pin-shaped inflorescences, suggesting that the HEC genes are probably involved in auxin-mediated control of gynoecium patterning.
Cdc42 is required for EGF-stimulated protrusion and motility in MTLn3 carcinoma cells
Authors: El-Sibai Mirvat , Nalbant Peri , Pang Huan , Flinn Rory J. , Sarmiento Corina , Macaluso Frank , Cammer Michael , Condeelis John S. , Hahn Klaus M. , Backer Jonathan M.
Published: September 2007

Cdc42 plays a central role in regulating the actin cytoskeleton and maintaining cell polarity. Here, we show that Cdc42 is crucial for epidermal growth factor (EGF)-stimulated protrusion in MTLn3 carcinoma cells. When stimulated with EGF, carcinoma cells showed a rapid increase in activated Cdc42 that is primarily localized to the protruding edge of the cells. siRNA-mediated knockdown of Cdc42 expression caused a decrease in EGF-stimulated protrusion and reduced cell motility in time-lapse studies. These changes were correlated with a decrease in barbed-end formation and Arp2/3 localization at the cell edge, and a marked defect in actin filament branching, as revealed by rotary-shadowing scanning electron microscopy. Upstream of Arp2/3, Cdc42 knockdown inhibited EGF-stimulated activation of PI 3-kinase at early (within 1 minute) but not late (within 3 minutes) time points. Membrane targeting of N-WASP, WAVE2 and IRSp53 were also inhibited. Effects on WAVE2 were not owing to Rac1 inhibition, because WAVE2 recruitment is unaffected by Rac1 knockdown. Our data suggest that Cdc42 activation is crucial for the regulation of actin polymerization in carcinoma cells, and required for both EGF-stimulated protrusion and cell motility independently of effects on Rac.
RCC1 isoforms differ in their affinity for chromatin, molecular interactions and regulation by phosphorylation
Authors: Hood Fiona E. , Clarke Paul R.
Published: September 2007

RCC1 is the guanine nucleotide exchange factor for Ran GTPase. Generation of Ran-GTP by RCC1 on chromatin provides a spatial signal that directs nucleocytoplasmic transport, mitotic spindle assembly and nuclear envelope formation. We show that RCC1 is expressed in human cells as at least three isoforms, named RCC1α, RCC1β and RCC1γ, which are expressed at different levels in specific tissues. The β and γ isoforms contain short inserts in their N-terminal regions (NTRs) that are not present in RCC1α. This region mediates interaction with chromatin, binds importin α3 and/or importin β, and contains regulatory phosphorylation sites. RCC1γ is predominantly localised to the nucleus and mitotic chromosomes like RCC1α. However, compared to RCC1α, RCC1γ has a greatly reduced interaction with an importin α3-β and a stronger interaction with chromatin that is mediated by the extended NTR. RCC1γ is also the isoform that is most highly phosphorylated at serine 11 in mitosis. Unlike RCC1α, RCC1γ supports cell proliferation in tsBN2 cells more efficiently when serine 11 is mutated to non-phosphorylatable alanine. Phosphorylation of RCC1γ therefore specifically controls its function during mitosis. These results show that human RCC1 isoforms have distinct chromatin binding properties, different molecular interactions, and are selectively regulated by phosphorylation, as determined by their different NTRs.
Interdependency of formation and localisation of the Min complex controls symmetric plastid division
Authors: Maple Jodi , Møller Simon G.
Published: September 2007

Plastid division represents a fundamental biological process essential for plant development; however, the molecular basis of symmetric plastid division is unclear. AtMinE1 plays a pivotal role in selection of the plastid division site in concert with AtMinD1. AtMinE1 localises to discrete foci in chloroplasts and interacts with AtMinD1, which shows a similar localisation pattern. Here, we investigate the importance of Min protein complex formation during the chloroplast division process. Dissection of the assembly of the Min protein complex and determination of the interdependency of complex assembly and localisation in planta allow us to present a model of the molecular basis of selection of the division site in plastids. Moreover, functional analysis of AtMinE1 in bacteria demonstrates the level of functional conservation and divergence of the plastidic MinE proteins.
Uniform strain in broad muscles: active and passive effects of the twisted tendon of the spotted ratfish Hydrolagus colliei
Authors: Dean Mason N. , Azizi Emanuel , Summers Adam P.
Published: September 2007

A muscle's force output depends on the range of lengths over which its fibers operate. Regional variation in fiber shortening during muscle contraction may translate into suboptimal force production if a subset of muscle fibers operates outside the plateau of the length–tension curve. Muscles with broad insertions and substantial shortening are particularly prone to heterogeneous strain patterns since fibers from different regions of the muscle vary in their moment arms, with fibers further from the joint exhibiting greater strains. In the present study, we describe a musculotendon morphology that serves to counteract the variation in moment arm and fiber strains that are inherent in broad muscles. The tendon of the anterior jaw adductor of the spotted ratfish Hydrolagus colliei is twisted such that the distal face of the muscle inserts more proximally than the proximal face. Using quantitative geometric models based on this natural morphology, we show that this inversion of insertion points serves to equalize strains across the muscle such that at any gape angle all fibers in the muscle are operating at similar positions on their length–tension curves. Manipulations of this geometric model show that the natural morphology is `ideal' compared to other hypothetical morphologies for limiting fiber strain heterogeneity. The uniform strain patterns predicted for this morphology could increase active force production during jaw closing and also decrease passive resistance to jaw opening. This divergence from `typical' tendon morphology in the jaw adductors of H. colliei may be particularly important given the demands for high force production in durophagy.
Organometallic Electron-Reservoir Complexes. Concepts and Applications
Authors: Astruc Didier
Published: September 2007

The 19-electron complexes [FeI(η5-C5R5)(η6-arene)] (R=H, arene = C6Me6, 1,3,5-tBu3C6H3; R=Me, arene = C6Me6, C6Et5H) are thermally stable and serve as strong single-electron reductant in a variety of stoichiometric and catalytic electron-transfer processes that are detailed in this review (prototype: [FeI(η5-C5H5)(η6-C6Me6)]). They are electron-reservoirs because their redox potential is very negative and they form a redox system for which both redox forms are stable. In this sense, they are Green redox reagents, since the oxidized form is recovered after use and is even frequently catalytically used. Symmetrically, the 17-electron complex [FeIII(η5-C5R5)(η6-C6Me6)][SbCl6]2, the strongest organometallic single-electron oxidant with a redox potential 1 V more positive than that of its isoelectronic ferrocenium analog, is a reservoir of electron hole.
Demonstration of the Importance of Metal Ion Speciation in Bioactive Systems
Authors: Kiss Tamás , Odani Akira
Published: September 2007

This paper gives insight into chemical speciation. After a brief introduction, the methods available to study solution state of metal ions and the importance of speciation in biology are discussed through different examples. Speciation of toxic AlIII, beneficial CuII and CaII and potentially medicinal PdII and VOIV in various biofluids and tissues is discussed in order to describe the solution state of these metal ions in an organism. The relevance of ternary complex formation with endogenous biomolecules is emphasised. The importance of the biospeciation of AlIII ion in its transport and involvement in neurological disorders, of the actual chemical form of the insulin-mimetic VOIV complexes in its biological occurrence and CaII in mineralization/demineralization processes is discussed. The role of time, i.e., the kinetic aspects of biospeciation, is discussed in the case of the transport of AlIII and CuII and some PdII complexes (models of the anticancer PtII complexes) in blood serum.
Phase Transitions and Molecular Motions in Guanidinium-d6 Trihalogenomercurates(II) [C(ND2)3]HgBr3 and [C(ND2)3]HgI3 as Investigated by Means of 81Br and 127I NQR and 2H NMR
Authors: Yamada Koji , Terao Hiromitsu , Sumimura Kazuko , Hashimoto Masao , Ohki Hiroshi , Okuda Tsutomu
Published: September 2007

The temperature dependence of 2H NMR spectra and 81Br and 127I NQR frequencies was investigated for the deuterated compounds of [C(NH2)3]HgBr3 and [C(NH2)3]HgI3 between 77 and ca. 400 K. Due to deuteration, the phase-transition temperatures of the iodine compound were increased by 2 and 6 K for the second-order (251 K) and the first-order (210 K) phase transitions, respectively. Distinctive 127I NQR frequency-shifts of more than 200 kHz were observed in the intermediate phase of the iodine compound on deuteration. The temperature dependences of the 2H NMR spectra for [C(ND2)3]HgBr3 and [C(ND2)3]HgI3 could be explained by invoking C3 reorientation of the guanidinium cation. The activation energies for the reorientation evaluated from 2H NMR were consistent with the former 1H NMR T1 results with the exception of the low-temperature phase of the iodine compound. The quite low activation energy from 2H NMR spectrum for this phase may indicate that the quenching of the orientation disordering of the cations is responsible for the fade-out phenomenon in the 127I NQR resonance lines below ca. 100 K.
Quantum Chemical Study on Stability and Reactivity of 1-Aminocyclopropane-1-carboxylic Acid Amine Radical Cation
Authors: Ito Mika , Tokiwa Hiroaki
Published: September 2007

The stability and reactivity of the 1-aminocyclopropane-1-carboxylic acid (ACC) amine radical cation, which is a key intermediate of ethylene biosynthesis in plants, were examined by quantum chemical calculations. The local interactions to stabilize radical species were treated with a hydrated cluster. Potential energy curves were obtained for two types of reactions from ACC amine radical cation: (1) direct ring opening of ACC amine radical cation, followed by proton abstraction from the amino group, and (2) proton abstraction from the amino group, followed by ring opening of ACC aminyl radical. A remarkable difference was found in the ring-opening processes of reactions (1) and (2). Rate constants (k) of 6.10×1012 and 8.89×109 s−1 at 298.15 K were estimated for the ring openings of ACC amine radical cation and ACC aminyl radical, respectively, at the B3LYP/6-31+G(d,p) level, and were in agreement with experimental results. The ring opening of ACC amine radical cation was 103-fold faster than that of ACC aminyl radical with almost no barrier height. It was thus quantitatively demonstrated that reaction (1) was more favorable than reaction (2) for ethylene synthesis.
Hydration Structure of l-Hydrogenglutamate Ion in Concentrated Aqueous Solutions
Authors: Kameda Yasuo , Sasaki Motoya , Amo Yuko , Usuki Takeshi
Published: September 2007

Neutron diffraction measurements were carried out on 14N/15N isotopically substituted aqueous 5 mol % sodium l-hydrogenglutamate solutions in D2O in order to obtain direct information concerning the structure of the first hydration shell around the amino-group of the l-hydrogenglutamate ion. Hydration parameters were determined through the least-squares fitting analysis of the observed intermolecular difference function, ΔNinter(Q). It was shown that, on average, 3.1(1) D2O molecules were hydrogen-bonded to the amino-hydrogen atoms of the hydrogenglutamate ion with interatomic distances of rNOW=2.92(2) and rNDW=3.47(1) Å, respectively.
Calorimetric Finding of Phase and Glass Transitions Concerning the Ordering of the Water Located between the Silicate Layers of the Clay Na-RUB-18
Authors: Watanabe Keisuke , Oguni Masaharu
Published: September 2007

The behavior of the water accommodated between the silicate layers of a clay Na8[Si32O64(OH)8]·32H2O was investigated by using adiabatic calorimetry. A phase transition was observed showing a heat-capacity peak at 194 K and its entropy was roughly estimated to be 5.2 J K−1 (H2O-mol)−1. The transition was interpreted to be essentially due to an order–disorder process involving two orientations of the water molecule which can form hydrogen bonds with siloxane-oxygen atoms. It is thought that the water molecules move with a large amplitude of vibration as well as disorder between the two permissible orientations at room temperature and become gradually ordered to take a more stable orientation of the two below 194 K. A glass transition was found at a temperature Tg=106 K, due to freezing of the water molecule in the orientations, which causes a little disorder to remain. The potential barrier (Δεa) of the reorientation was assessed from the Tg to be about 34 kJ mol−1, which corresponds to the energy to break two hydrogen-bonds. There remains a possibility that the silanol-hydrogen atom takes a tunneling state involving two accessible sites between two silanol-oxygen atoms; however, it was not confirmed in this work.
Experimental Thermochemical Study of 6-Chloro-2,3-dimethylquinoxaline 1,4-Dioxide and DFT Evaluation of the N–O Bond Enthalpies in Related Haloquinoxalines
Authors: Gomes José R B , Vieira Mónica A A , Stovall Dawn M , Acree William E , Ribeiro da Silva Maria D M C
Published: September 2007

The standard molar enthalpy of formation at T=298.15 K of 6-chloro-2,3-dimethylquinoxaline 1,4-dioxide in the gas-phase was derived using the values of the enthalpies of combustion for the crystalline solid, measured by using rotating-bomb combustion calorimetry, and of the enthalpies of sublimation, measured by using Calvet microcalorimetry. This value was used for calibrating the computational procedure employed to estimate the gas-phase enthalpies of formation for the deoxygenated quinoxaline derivatives and also to compute the first, second, and mean (N–O) bond dissociation enthalpies in the gas-phase. The B3LYP/6-311+G(2d,2p) calculations were also extended to the fluorine, bromine, and iodine derivatives and to the isomers with a halogen substituted at position 5. When the halogen atom enters the same position in the quinoxaline ring, it was found that the substituent had almost no influence on the computed (N–O) bond dissociation enthalpies, except for 5-fluoro-2,3-dimethylquinoxaline 1,4-dioxide.
Solid-State Structures of trans-[RuCl2{Cl2PN(Me)N(Me)PCl2}2] and cis-[MCl2{Cl2PN(Me)N(Me)PCl2}] (M = PtII and PdII) Studied by X-ray Crystallography and 13C CPMAS NMR Spectroscopy
Authors: Takara Satoshi , Batsanov Andrei S , Schaffer Douglas J , Takase Michael , Kunishige Janice A , Lee Susan J
Published: September 2007

Solid-state structures of trans-[RuCl2{Cl2PN(Me)N(Me)PCl2}2] (1), cis-[PdCl2{Cl2PN(Me)N(Me)PCl2}] (2), and cis-[PtCl2{Cl2PN(Me)N(Me)PCl2}] (3) were studied by using 13C CPMAS NMR spectroscopy and X-ray crystallography. The ruthenium atom in 1 was on a crystallographic inversion center and had a slightly distorted octahedral coordination. 2 and 3 contained palladium and platinum atoms in a square-planar geometry, respectively. In 2, axial sites of the Pd atom were filled by intermolecular Pd···Cl contacts to form an infinite chain. Molecules of 3 pack in an edge-to-face manner and no obvious “axial” contacts at the Pt atom were observed. Different geometries of hydrazide nitrogens in 1, 2, and 3 were observed: in 1 and 2, one of the nitrogen atoms was trigonal planar and the other one was pyramidal; the two hydrazine nitrogen atoms in 3 had trigonal planar geometry. 13C CPMAS NMR spectra are consistent with X-ray data. The P–N distances are shorter than normally accepted P–N single bond lengths, suggesting a degree of P–N π bonding.
Convenient Synthesis of 3-Substituted Benzo[b]thiophenes by Iodine-Mediated Cyclization of α-Substituted 2-(1-Phenylethylthio)styrenes
Authors: Kobayashi Kazuhiro , Nakamura Daizo , Miyamoto Kazuna , Morikawa Osamu , Konishi Hisatoshi
Published: September 2007

A new and convenient method for the preparation of 3-substituted benzo[b]thiophenes was developed. α-Substituted 2-(1-phenylethylthio)styrenes, which could easily be prepared from 2-mercaptophenyl ketones or benzenethiols in two or three steps, respectively, underwent 5-endo cyclization on treatment with iodine in the presence of sodium hydrogencarbonate in acetonitrile at room temperature to give 3-substituted benzo[b]thiophenes in fair to good yields.
Conductive, Magnetic, and Optical Properties of Sterically Hindered Dodecithiophenes. Evidence for the Coexistence of Bipolaron and π-Dimer
Authors: Kurata Tomoyuki , Mohri Takashi , Takimiya Kazuo , Otsubo Tetsuo
Published: September 2007

Conductive, magnetic, and optical properties of sterically hindered dodecithiophenes bearing bulky 2,2-bis(butoxymethyl)-1,3-propanediyl groups were examined. At high doping with FeCl3, a completely hindered dodecithiophene had only a poor conductivity of 5×10−4 S cm−1, but two partially hindered dodecithiophenes had relatively high conductivities of 1.9 and 0.6 S cm−1, which are one or two orders lower than the conductivity (38 S cm−1) of the unhindered dodecithiophene. Despite having different structures and conductivities, all of the doped solids of these dodecithiophenes were magnetically inactive and demonstrated similar optical absorption spectra in the near infrared region, as generally observed for polythiophenes. On the other hand, their optical spectra in dichloromethane were quite different from one another. A solution spectrum of the unhindered dodecithiophene under high doping was characterized by two absorption transitions assignable to a π-dimer. On the other hand, a solution spectrum of the completely hindered dodecithiophene was characterized by an absorption transition due to a bipolaron. Furthermore, the solution spectra of two partially hindered dodecithiophenes could be explained as an overlap of both π-dimeric and bipolaronic bands. From these results, both π-dimer and bipolaron species appear to serve as active charge carriers in conductive poly(oligo)thiophenes.
Cationic Palladium Complex-Catalyzed Hydrosilylative Cross-Coupling of Alkynes with Alkenes. 1,4-Addition of Trichlorosilane to Form 4-Silyl-1-butene Framework
Authors: Shimamoto Takamitsu , Chimori Motoharu , Sogawa Hiroaki , Harada Yuki , Aoki Masaharu , Yamamoto Keiji
Published: September 2007

A new hydrosilylative cross-coupling reaction of a variety of alkynes with several alkenes, which is catalyzed by a cationic palladium complex A (1 mol %) without or with added PPh3 ligand, was studied systematically. The reaction using HSiCl3 as an addend afforded more or less two types of products consisting of four possible derivatives, R1CH=CR2–CHR3–CHR4–SiCl3, which always contained 4-trichlorosilyl-1-butene frameworks, in acceptable combined yields. The coupling pattern was dependent both on the precatalyst A in the absence or presence of PPh3 [also P(C6F5)3] and on the combination of the alkyne and alkene counterpart employed. A possible catalytic cycle that involves an initial hydropalladation of an alkyne, followed by a facile and specific carbopalladation of an alkene, is proposed. At the same time, the lack of regioselectivity in the latter step is noted. The effect of the added phosphine ligand on the coupling pattern is briefly discussed.
Photoisomerization Mechanism of All-Z-Oligo(phenylenevinylene)s
Authors: Ikegami Masashi , Nagao Masato , Katayama Hiroyuki , Ozawa Fumiyuki , Arai Tatsuo
Published: September 2007

Photoisomerization mechanism of para-substituted oligo(phenylenevinylene)s (OPVs) was dependent on the number of olefin units. While mono-olefin OPV1 underwent two-way photoisomerization, other OPVs (OPV2, OPV3, and OPV4) underwent photochemical one-way Z-to-E isomerization. As the number of olefin units increased, contribution of the triplet excited state to the Z-to-E isomerization becomes larger.
Columnar Liquid-Crystalline Imidazolium Salts. Effects of Anions and Cations on Mesomorphic Properties and Ionic Conductivities
Authors: Yoshio Masafumi , Ichikawa Takahiro , Shimura Harutoki , Kagata Takayoshi , Hamasaki Atsushi , Mukai Tomohiro , Ohno Hiroyuki , Kato Takashi
Published: September 2007

Two series of 1-methyl-3-[3,4,5-tris(alkyloxy)benzyl]imidazolium salts (1(n/X−); n=8, 12, 16, and 18) and 1,2-dimethyl-3-[3,4,5-tris(dodecyloxy)benzyl]imidazolium salts (2(12/X−)) containing anions (X−), such as tetrafluoroborate, hexafluorophosphate, trifluoromethylsulfonate, and bis(trifluoromethylsulfonyl)imide, have been synthesized. The thermal properties of these salts were characterized by differential scanning calorimetry, polarizing optical microscopy, and X-ray diffraction. The salts form hexagonal columnar liquid-crystalline phases except for 1(8/X−) and 1(12/X−) containing CF3SO3− and (CF3SO2)2N−, and 2(12/(CF3SO2)2N−) which melt directly to isotropic ionic liquids. The clearing points show a decreasing trend with an increase in the size of anions. The ionic conductivities of 1(16/X−) forming columnar phases have been measured by using an alternating current impedance method. The conductivities depend on the nature of anions, suggesting that the predominant conduction mechanism is hopping and/or diffusion of anions in the columnar structures.
Surface Grafting of Polypyrrole onto Silicon Wafers
Authors: Sohn Daewon , Moon Hyoseung , Fasolka Michael J , Eidelman Naomi , Koo Sang-Mo , Richter Curt A , Park SeungEun , Kopanski J J , Amis Eric
Published: September 2007

A micromolding technique in capillaries was adapted to make uniform patterns of polypyrrole (Ppy), and the conductivities of the patterns were measured by direct contact IV curves and conductance AFM methods. Noncovalently bound Ppy patterns have high conductivity (low resistivity) before doping and brittle characteristics. However, the covalently grafted Ppy pattern shows relatively low conductivity and sticky viscoelastic properties.
Construction of Highly Oriented Self-assembled Monolayer of Alkyldithiol with Ferrocene on Gold (111) Using Underpotentially Deposited Lead Submonolayer as a Template
Authors: Kondo Toshihiro , Sato Saori , Maeda Wakana
Published: September 2007

Highly oriented self-assembled monolayer (SAM) of alkyldithiol with a ferrocene group was constructed on Au(111) surface using underpotentially deposited (UPD) Pb submonolayer as a template. Orientation of this SAM was confirmed by comparing amounts of ferrocene moiety and Au–S bonding.
Preparation of Novel Polymer Assemblies, “Lactosome”, Composed of Poly(l-lactic acid) and Poly(sarcosine)
Authors: Makino Akira , Yamahara Ryo , Ozeki Eiichi , Kimura Shunsaku
Published: September 2007

Novel amphiphilic block polymers composed of poly(l-lactic acid) (PLLA) and poly(sarcosine) (PS) were synthesized by successive polymerizations of lactide and sarcosine N-carboxy anhydride (NCA). The degree of polymerization of each block was controlled by the monomer/initiator ratio in feed. The block polymers were successfully dispersed in buffer with taking various morphologies of micelle, lamellar, and vesicle depending on the hydrophobic/hydrophilic balance of the copolymers. The size of the molecular assemblies was in the range from 20 to 200 nm, which may be available for drug delivery system (DDS) as nanocarrier.
Photoinduced Surface Relief Structures Formed on Polymer Films Mixed with Diarylethenes
Authors: Ubukata Takashi , Yamaguchi Shuro , Yokoyama Yasushi
Published: September 2007

Formation of photoinduced surface relief (PSR) was investigated using a poly(methyl methacrylate) film mixed with a series of symmetrical diarylethenes (DAEs). PSRs were formed on films with some DAEs having 2-benzothienyl groups by the patterned light irradiation (>350 nm) owing to material migration.
Reversible Thermochromic Change of Molecular Architecture for a Diacetylene Derivative 10,12-Pentacosadiynoic Acid Self-assembled Thin Films on Ag Surfaces
Authors: Lim Jong Kuk , Lee Yunhee , Lee Kangtaek , Gong Myoungseon , Joo Sang-Woo
Published: September 2007

Molecular architecture of the self-assembled thin films of 10,12-pentacosadiynoic acid (PCDA) anchoring on Ag surfaces via its carboxylate group appeared to have a reversible thermochromic disordered-to-regular trans-zigzag transition at ≈65 °C by an external reflectance infrared spectroscopy and surface-enhanced Raman scattering study.
Determinants of targeting by endogenous and exogenous microRNAs and siRNAs
Authors: Nielsen Cydney B. , Shomron Noam , Sandberg Rickard , Hornstein Eran , Kitzman Jacob , Burge Christopher B
Published: September 2007

Vertebrate mRNAs are frequently targeted for post-transcriptional repression by microRNAs (miRNAs) through mechanisms involving pairing of 3′ UTR seed matches to bases at the 5′ end of miRNAs. Through analysis of expression array data following miRNA or siRNA overexpression or inhibition, we found that mRNA fold change increases multiplicatively (i.e., log-additively) with seed match count and that a single 8 mer seed match mediates down-regulation comparable to two 7 mer seed matches. We identified several targeting determinants that enhance seed match-associated mRNA repression, including the presence of adenosine opposite miRNA base 1 and of adenosine or uridine opposite miRNA base 9, independent of complementarity to the siRNA/miRNA. Increased sequence conservation in the ∼50 bases 5′ and 3′ of the seed match and increased AU content 3′ of the seed match were each independently associated with increased mRNA down-regulation. All of these determinants are enriched in the vicinity of conserved miRNA seed matches, supporting their activity in endogenous miRNA targeting. Together, our results enable improved siRNA off-target prediction, allow integrated ranking of conserved and nonconserved miRNA targets, and show that targeting by endogenous and exogenous miRNAs/siRNAs involves similar or identical determinants.
Invisible second-order campaigns? A longitudinal study of the coverage of the European Parliamentary elections 1979–2004 in four German quality newspapers
Authors: Wilke Jürgen , Reinemann Carsten
Published: September 2007

In recent years, the European Union (EU) has become more and more important in the lives of Europeans due to its growing authority in policy-making. In contrast to that, there still are several shortcomings in our knowledge of how European institutions, political processes, and events are presented in the media. This paper focuses on the coverage of the elections of the European Parliament (EP) because of two contradictory developments. Although the relevance of the EP to EU decision-making has considerably increased since 1979, voter interest and voter turnout at EP elections has been declining. Against this backdrop the paper (a) investigates the long-term development of EP election coverage in German newspapers and (b) compares EP and national election campaign coverage. Based on a content analysis of the coverage of four German quality newspapers of all six European election campaigns that took place since 1979, the analysis shows that there has not been an increase in EP election coverage, that EP elections were covered much less frequently than national elections, that, like in national elections, there was a trend towards more subjectivity in EP election coverage, that EP elections were looked at from a mainly national perspective, and that the degree of personalization was lower in EP than in national election coverage. In addition, explicit assessments of the EP's political relevance gave a better picture of the real development than one would expect from the analysis of the mere amount of coverage.
Government communication about policy intentions: Unwanted propaganda or democratic inevitability? Surveys among government communication professionals and journalists in Belgium and the Netherlands
Authors: Gelders Dave , De Cock Rozane , Neijens Peter , Roe Keith
Published: September 2007

Recent developments in politics, the media, and society have stressed the rising importance of public communication from the government about policies not yet been adopted by Parliament. Government communication professionals and journalists are key figures in this process but conflicting interests mark a tense relationship. Up until now, few empirical studies have been conducted to shed light on the opinions of both professions concerning ‘Communication about Not yet Adopted Policy’ (CNAP). We studied the issue in both the Netherlands and Belgium because research has shown that these countries stand out in regard to debating and reflecting on CNAP. This article maps recent Dutch empirical research and a more elaborated Belgian study, and shows that CNAP is generally accepted by government communication professionals and journalists. Moreover, the Belgian study shows the respondents' opinions regarding the acceptance of CNAP, their arguments, and the conditions CNAP must meet.
Rutin content of the grain of buckwheat ( Fagopyrum esculentum Moench. and Fagopyrum tataricum Gaertn.) varieties growtn in southern Italy
Authors: Brunori A. , Végvári G.
Published: September 2007

The rutin content of the grain of 31 buckwheat varieties (28F. esculentumand 3F. tataricum) grown on the high plain of Sila (Region of Calabria) and on the massif of Pollino (Region of Basilicata) presented a substantial degree of variation.Among theF. esculentumvarieties the lowest values were found for Botan and Spacinska, while the highest contents were observed in the varieties Emka and Lechnicka Krajova. As expected, the rutin content of the grain ofF. tataricumwas higher than that ofF. esculentum, with the variety Donan showing the highest value.In view of the role of rutin in conferring most of the functional food characteristics of buckwheat, knowledge of the grain rutin content expressed in a specific environment, together with the yield potential, is important for the identification of buckwheat varieties worth adopting in an area such as the high plain of Sila, which, thanks to its extent, has the potential to represent a novel territory for the profitable cultivation of buckwheat in Italy.
Correlations and path analysis of yield components in synthetic varieties of sunflower ( Helianthus annuus L.)
Authors: Göksoy A. , Turan Z.
Published: September 2007

This study was made in order to determine the correlations between seed yield and some yield components, and the direct and indirect effects of these characters on seed yield in sunflower. Four experimental synthetic varieties (Syn 1s), their parental mixtures (Syn Os) and two standard varieties (open pollinated: Vniimk 8931, and commercial hybrid: Sunbred-281) were evaluated in replicated field trials under Turkish conditions in 1995, 1996 and 1997. Agronomic characteristics such as plant height, head diameter, number of seeds per head, 1000-seed weight and seed yield were observed for correlations and path coefficient analysis.According to the results, seed yield gave significant positive correlations with plant height, head diameter, number of seeds per head and 1000-seed weight. The highest positive correlation was observed between seed yield and number of seeds per head (r=0.890**). Path analysis indicated that the number of seeds per head gave the greatest direct effect (+0.7269) on seed yield, followed by 1000-seed weight (+0.3215) and head diameter (+0.1689). The percentage of direct effects on seed yield was 80.8%, 50.6% and 24.0% for number of seeds per head, 1000-seed weight and head diameter, respectively.