bluuebunny/crossref_metadata_2025 huggingface dataset:
Supramolecular Structure of Self‐Assembling Alamethicin Analog Studied by ESR and PELDOR
Authors: Milov Alexander D. , Samoilova Marina I. , Tsvetkov Yuri D. , Jost Micha , Peggion Cristina , Formaggio Fernando , Crisma Marco , Toniolo Claudio , Handgraaf Jan‐Willem , Raap Jan
Published: June 2007

Three analogs of alamethicin F50/5, labelled with the TOAC (=‘2,2,6,6‐tetramethylpiperidin‐1‐oxyl‐4‐amino‐4‐carboxylic acid’) spin label at positions 1 (Alm1), 8 (Alm8), and 16 (Alm16), resp., were studied by Electron‐Spin‐Resonance (ESR) and Pulsed Electron–Electron Double‐Resonance (PELDOR) techniques in solvents of different polarity to investigate the self‐assembly of amphipathic helical peptides in membrane‐mimicking environments. In polar solvents, alamethicin forms homogeneous solutions. In the weakly polar chloroform/toluene 1 : 1 mixture, however, this peptide forms aggregates that are detectable at 293 K by ESR in liquid solution, as well as by PELDOR in frozen, glassy solution at 77 K. In liquid solution, free alamethicin molecules and their aggregates show rotational‐mobility correlation times τr of 0.87 and 5.9 ns, resp. Based on these values and analysis of dipole–dipole interactions of the TOAC labels in the aggregates, as determined by PELDOR, the average number N of alamethicin molecules in the aggregates is estimated to be less than nine. A distance‐distribution function between spin labels in the supramolecular aggregate was obtained. This function exhibits two maxima: a broad one at a distance of 3.0 nm, and a wide one at a distance of ca. 7 nm. A molecular‐dynamics (MD)‐based model of the aggregate, consisting of two parallel tetramers, each composed of four molecules arranged in a ‘head‐to‐tail’ fashion, is proposed, accounting for the observed distances and their distribution.
Ligand‐Induced Extramembrane Conformation Switch Controlling Alamethicin Assembly and the Channel Current
Authors: Futaki Shiroh , Asami Koji
Published: June 2007

In this review, we describe our approach to creating artificial receptor‐channel proteins or sensor systems, using an extramembrane segment conformationally switchable by external stimuli. Alamethicin is known to self‐assemble in membranes to form ion channels with various open states. Employment of an α‐helical leucine‐zipper segment resulted in the effective modulation of the association states of alamethicin to produce a single predominant channel‐open state. A decrease in the helical content of the extramembrane segments was found to induce a channel‐current increase. Therefore, conformational changes in the extramembrane segments induced by the interaction with ligands can be reflected in the current levels.
Enzymatic Reaction in a Vesicular Microreactor: Peptaibol‐Facilitated Substrate Transport
Authors: Kropacheva Tatyana N. , Raap Jan
Published: June 2007

Catalytic reactions performed with enzymes localized in lipid vesicles or in whole cells represent a new, promising approach in biocatalysis. The delivery of different substrates into these micro‐ or nano‐‘reactors’ requires a sufficient permeability of lipid membranes. To increase the permeability of lipid bilayers, one may use different membrane‐active peptides, including peptaibols. In the present study, the trypsin‐catalyzed hydrolysis of Nα‐benzoyl‐L‐arginine‐para‐nitroanilide (BAPA; 1) was studied in a phospholipid vesicular system made of phosphatidylcholine (POC), in the presence of the peptaibols alamethicin (ALM) or zervamicin IIB (ZER). Two different manners of compartmentalization of substrate and enzyme (enzyme‐ vs. substrate‐containing vesicles) were used. The kinetics parameters of the reaction in homogeneous solution and in the vesicular systems were determined. The rate of the extra‐ or intravesicular enzymatic reaction was found to be controlled by substrate diffusion through the lipid bilayer. In comparison with untreated vesicular systems, an up to seven‐fold increase in reaction rate was observed in the presence of either ALM or ZER.
Synthetic, Biologically Active Amphiphilic Peptides
Authors: Yamnitz Carl R. , Gokel George W.
Published: June 2007

Amphiphilic peptides typically consist of a peptide portion that may be 5–25 (or more) amino acids in length. The hydrophobic portion may be a single fatty acid residue, but can also be more elaborate. The main focus of this article lies on the family of synthetic anion binders (SATs) of the general structure (R1)2N‐COCH2OCH2CO‐(Aaa)n‐OR3. The most‐common R1 group is the octadecyl (C18H37) group. The most studied peptide sequence in this family is (Gly)3‐Pro‐(Gly)3, although different sequences (and longer and shorter peptides) have been prepared as well. The C‐terminal ester residue providing the most effective anion release from liposomes is heptyl (C7H15), although many others have been examined. The compound (C18H37)2N‐COCH2OCH2CO‐(Gly)3‐Pro‐(Gly)3‐OBn (Bn=benzyl) was found to mediate Cl− transport in mouse epithelial cells.
Spirodionic Acid, a Novel Metabolite from Streptomyces sp., Part 2: Total Synthesis through a Twofold Michael Addition as a Selective Spiroannelation Strategy
Authors: Siewert Jürgen , Textor Adriana , Grond Stephanie , von Zezschwitz Paultheo
Published: June 2007

To elucidate the structure of the new natural product spirodionic acid, which has three stereogenic centers of hitherto unknown configuration, two 4‐ethenylspiro[4.5]dec‐6‐en‐1,8‐diones with opposite relative configuration at C4 and C5 were prepared. The first access involved the synthesis of 3‐ethenyl‐2‐formylcyclopentanone (8) using a three‐component coupling process. A sequence of Michael addition to penten‐3‐one (7) and intramolecular aldol condensation then led to the highly selective formation of the 4S*,5S*‐configured spirocycle 5. In contrast, a selective spiroannelation of a cyclohexenone ring was accomplished by a novel type of twofold Michael addition to the dialkenyl ketone 11 with subsequent dehydrogenation to furnish the 4S*,5R*‐configured spirocycle 25. Diastereoselective methylation and oxidative degradation then completed a highly efficient synthesis of the natural product as prerequisite for the assignment of its absolute configuration.
Investigation of an Acid–Base and Redox Molecular Switch: From Bulk to the Single‐Molecule Level
Authors: Al‐Kaysi Rabih O. , Bourdelande José Luis , Gallardo Iluminada , Guirado Gonzalo , Hernando Jordi
Published: June 2007

In this work we investigate a new fluorescent molecular switch based on the interconversion between the fluorescent zwitterionic form (ZW1) and the non‐fluorescent anionic state (MC2) of a spirocyclic Meisenheimer complex of 1,3,5‐trinitrobenzene. Density functional theory molecular orbital calculations reveal that photo‐induced electron transfer from a guanidine group to the trinitrocyclohexadiene fluorophore of the complex quenches the emission from MC2. Protonation, as well as coordination of other Lewis acids to the guanidine group, suppress the quenching mechanism and allow the complex to fluoresce. In agreement with the calculations, reversible on–off fluorescence switching of the ZW1–MC2 bulk system occurs by protonation–deprotonation of the guanidine moiety upon acid–base addition. Interestingly, spectroelectrochemical ensemble measurements show that switching of the ZW1–MC2 pair can also be attained electrochemically, thus unraveling the versatile functioning of this system. The ultimate limit of monitoring the reversible on–off operation of individual switch molecules is reached by means of single‐molecule fluorescence spectroscopy, which demonstrates the potential of the ZW1–MC2 system to be used as a true single‐molecule switch on the nanometer scale.
Mannosylated G(0) Dendrimers with Nanomolar Affinities to Escherichia coli FimH
Authors: Touaibia Mohamed , Wellens Adinda , Shiao Tze Chieh , Wang Qingan , Sirois Suzanne , Bouckaert Julie , Roy René
Published: June 2007

Pentaerythritol and bis‐pentaerythritol scaffolds were used for the preparation of first generation glycodendrimers bearing aryl α‐D‐mannopyranoside residues assembled using single‐step Sonogashira and click chemistry. The carbohydrate precursors were built with either para‐iodophenyl, propargyl, or 2‐azidoethyl aglycones whereas the pentaerythritol moieties were built with terminal azide or propargyl groups, respectively. Cross‐linking abilities of this series of glycodendrimers were first evaluated with the lectin from Canavalia ensiformis (Concanavalin A). Surface plasmon resonance measurements showed these two families of mannosylated clusters as the best ligands known to date toward Escherichia coli K12 FimH with subnanomolar affinities. Tetramer 4 had a Kd of 0.45 nM. These clusters were 1000 times more potent than mannose for their capacity to inhibit the binding of E. coli to erythrocytes in vitro.
Methodology for the Calculation of the Potential of Mean Force for a Cation–π Complex in Water
Authors: Ghoufi Aziz , Archirel Pierre , Morel Jean‐Pierre , Morel‐Desrosiers Nicole , Boutin Anne , Malfreyt Patrice
Published: June 2007

We report potential of mean force (PMF) calculations on the interaction between the p‐sulfonatocalix[4]arene and a monovalent cation (Cs+). It has been recently shown from microcalorimetry and 133Cs NMR experiments that the association with Cs+ is governed by favourable cation–π interactions and is characterized by the insertion of the cation into the cavity of the macrocycle. We show that the PMF calculation based upon a classical model is not able to reproduce both the thermodynamic properties of association and the insertion of the cation. In order to take into account the different contributions of the cation–π interactions, we develop a new methodology consisting of changing the standard PMF by an additional contribution resulting from quantum calculations. The calculated thermodynamic properties of association are thus in line with the microcalorimetry and 133Cs NMR experiments and the structure of the complex at the Gibbs free‐energy minimum shows the insertion of the cation into the cavity of the calixarene.
Sensitized Emission from Lanthanide‐Doped Nanoparticles Embedded in a Semiconductor Sol–Gel Thin Film
Authors: Sivakumar Sri , van Veggel Frank C. J. M. , Raudsepp Mati
Published: June 2007

In2O3 sol–gel thin films made with LaF3:Ln3+ (Ln=Er, Nd, and Eu) nanoparticles were prepared and showed sensitized emission of the lanthanide ions after In2O3 matrix excitation. The excitation spectra showed an In2O3 absorption band in addition to the excitation peaks of the lanthanide ions, clearly demonstrating that there is energy transfer from the In2O3 matrix to Ln3+ (Er3+, Nd3+, and Eu3+). Similarly, HfO2 and ZrO2 sol–gel thin films made with LaF3:Ln3+ nanoparticles also showed energy transfer from the semiconductor matrix to the lanthanide ions.
The Molecular Orientation of para‐Sexiphenyl on Cu(110) and Cu(110) p(2×1)O
Authors: Oehzelt Martin , Grill Leonhard , Berkebile Stephen , Koller Georg , Netzer Falko P. , Ramsey Michael G.
Published: June 2007

Controlling the molecular growth of organic semiconductors is an important issue to optimize the performance of organic devices. Conjugated molecules, used as building blocks, have an anisotropic shape and also anisotropic physical properties like charge transport or luminescence. The main challenge is to grow highly crystalline layers with molecules of defined orientation. The higher the crystallinity, the closer these properties reach their full intrinsic potential, while the orientation determines the physical properties of the film. Herein we show that the molecular orientation and growth can be steered by the surface chemistry, which tunes the molecule–substrate interaction. In addition, the oxygen reconstruction of the surface, demonstrates the flexibility of the organic molecules to adopt a given surface corrugation and their unique possibility to release stress by tilting.
Growth and characterization of pure and doped nonlinear optical l‐arginine acetate single crystals
Authors: Gulam Mohamed M. , Vimalan M. , Jesudurai J. G. M. , Madhavan J. , Sagayaraj P.
Published: June 2007

Single crystals of organic nonlinear optical material of pure, Cu2+ and Mg2+ doped L‐arginine acetate (LAA) were successfully grown by slow evaporation method at room temperature. The UV‐Vis‐NIR spectra of pure and doped LAA indicate that these crystals possess a wide optical transmission window from 240‐1600 nm. Non‐linear optical studies reveal that the SHG efficiency of LAA is nearly three times that of KDP. The dielectric response of the samples was studied in the frequency region 100 Hz to 2 MHz and the influence of Cu2+ and Mg2+ substitution on the dielectric behaviour had been investigated. Photoconductivity study proves that both pure and Cu2+ and Mg2+ doped LAA crystal exhibit positive photoconductivity. It is evident from the Vickers hardness study that the hardness of the crystal decreases with increasing load both for pure and doped samples. ESR studies confirmed the incorporation of Cu2+ into LAA and the value of g‐factor was found to be 2.1654. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Synthesis, growth and characterization of l‐alaninium oxalate ‐ a novel organic NLO crystal
Authors: Vimalan M. , Ramanand A. , Sagayaraj P.
Published: June 2007

Nonlinear optical material of L‐alaninium oxalate (LAO) has been synthesized and single crystals are grown by slow evaporation technique. The solubility data of LAO is determined in water. Single crystal X‐ray diffraction study showed that LAO belongs to orthorhombic system with a non‐centrosymmetric space‐group P212121. The functional groups have been identified from FT‐IR spectrum. The UV‐Vis‐NIR spectrum of LAO shows less optical absorption in the entire visible region. The second harmonic generation (SHG) in the material was estimated using Nd:YAG laser. The mechanical properties of the grown crystals are studied using Vickers microhardness tester. The AC and DC conductivity, and dielectric studies are also carried out and reported for the first time. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Three‐dimensional numerical investigation of the effects of an open window on the convective heat transfer of an oxide Czochralski system
Authors: Tavakoli M. H. , Wilke H.
Published: June 2007

A three‐dimensional numerical analysis was carried out for a real Czochralski crystal growth furnace containing only gas and without any melt and crystal in order to investigate the effects of a small observation window on the temperature and flow field of the system. For this approach, the induction heating equations, the Navier‐Stokes equation with Boussinesq approximation, the continuity and energy equations have been solved in cylindrical coordinates using the finite element method. It has been found that the flow and thermal fields in the system are obviously three‐dimensional and non‐axisymmetric. The gas enters the system through the window is directed towards the opposite side wall where it is divided into two parts of vertical direction as well as expands in horizontal direction. Consequently, there is a spiral gas flow in the crucible and afterheater which rotates upwards in azimuthal direction along the walls. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Nanocrystalline properties of chemically deposited (Cd0.95‐Pb0.05)S:CdCl2, Gd/Dy films
Authors: Bhushan S. , Shrivastava S.
Published: June 2007

Results of SEM and XRD studies, optical absorption spectra and photoluminescence emission spectra are presented for the films of (Cd0.95‐Pb0.05)S:CdCl2, Gd/Dy prepared by chemical bath deposition technique and using thiophenol and methanol as capping agents. The deposition of films is based on precipitation followed by condensation on the substrates. SEM studies show existence of irregular distribution of particles alongwith presence of rod/tube type structure. The XRD studies show diffraction lines of CdS, PbS and CdCl2. Blue shift has been observed in absorption spectra showing quantum confinement. Particle sizes determined from XRD studies and absorption spectral studies are found to lie in the nano range. Photoluminescence emission spectra consist of emissions in blue and green‐yellow regions. The observed emissions are related to the combination of defect levels and levels due to rare earths. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Crystal structure and electrochemical property of one‐dimensional complex: [K(cis‐syn‐cis‐ dicyclohexyl‐18‐crown‐6)]2[Cu(mnt)2]
Authors: Sun Yun‐Ming , Dong Feng‐Ying , Dou Jian‐Min , Li Da‐Cheng , Gao Xi‐Ke , Wang Da‐Qi
Published: June 2007

One metalorganic complex [K(cis‐syn‐cis‐ dicyclohexyl‐18‐crown‐6)]2[Cu(mnt)2] (mnt = maleonitriledithiolate) has been obtained by the reaction of dicyclohexyl‐18‐crown‐6 with K2mnt and CuCl2·2H2O. The title complex has been characterized by elementary analysis, FT‐IR, UV‐Vis spectroscopy and x‐ray single crystal diffraction. The title complex crystallizes in the triclinic space group P1 with crystallographic data: a = 10.870(6) Å, b = 11.536(6) Å, c = 12.904(7) Å, α = 101.541(10)°, β = 110.573(9)°, γ = 99.441(9)°, V = 1435.2(13) Å3, Z = 1, Dcalcd = 1.350 g/cm3, F(000) = 615, R1 = 0.0641, wR2 = 0.1475. It displays one‐dimensional chain‐like structure formed by [K(cis‐syn‐cis‐ dicyclohexyl‐18‐crown‐6)]+ complex cations and [Cu(mnt)2]2‐ complex anions through N‐K‐N interactions. Its electrochemical behavior has also been studied by the cyclic voltammetry. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Developmental and activity‐dependent regulation of ARMS/Kidins220 in cultured rat hippocampal neurons
Authors: Cortés Rosa Y. , Arévalo Juan Carlos , Magby Jason P. , Chao Moses V. , Plummer Mark R.
Published: June 2007

Neurotrophin activation of Trk receptors elicits diverse effects on neuronal survival, differentiation, and synaptic plasticity. One of the central questions is how specificity is encoded in neurotrophin receptor signaling and actions. A unique downstream protein is the Ankyrin‐Repeat Rich Membrane Spanning (ARMS)/Kinase D‐interacting substrate‐220 kDa (Kidins220), a very abundant scaffold protein in the hippocampus. To determine the roles of ARMS/Kidins220 in hippocampal neurons, we have analyzed the effects of synaptic activity upon the regulation and distribution of ARMS/Kidins220. At early times in vitro (<7 DIV), synaptic activity was low and ARMS/Kidins220 levels were high. As synaptic activity and markers for synapse maturation, such as PSD‐95, increased, ARMS/Kidins220 significantly decreased to a plateau by later times in vitro (>12 DIV). Immunocytochemistry showed ARMS/Kidins220 to be concentrated at the tips of growing processes in immature cultures, and more diffusely distributed in older cultures. To examine the apparent inverse relationship between activity and ARMS/Kidins220 levels, neuronal firing was manipulated pharmacologically. Chronic exposure to TTX increased ARMS/Kidins220 levels, whereas bicuculline caused the opposite effect. Moreover, using shRNA to decrease ARMS/Kidins220 levels produced a corresponding increase in synaptic activity. We find that ARMS/Kidins220 may function in neuronal development as an indicator and potentially as a homeostatic regulator of overall synaptic strength in hippocampal neurons. © 2007 Wiley Periodicals, Inc. Develop Neurobiol, 2007
Evolution of immunity and pathogens
Authors: Howard Jonathan C. , Jack Robert S.
Published: June 2007

The Cologne Spring Meeting of the Institute of Genetics focuses on a different topic each year. In Spring 2007, the meeting focused on the complex evolutionary relationships between hosts and pathogens.
Detection of beeswax adulterations using concentration guide‐values
Authors: Jiménez Juan José , Bernal José Luis , del Nozal María Jesús , Toribio Laura , Bernal José
Published: June 2007

The concentrations of 102 chemical compounds (saturated and unsaturated hydrocarbons, palmitates, total and free acids, total hydroxyacids, total and free alcohols, acidic monoesters and monoesterified 1,2,3‐propanetriols) have been determined by GC/FID on white and yellow comb beeswax of Apis mellifera from different regions of Spain. Guide‐value ranges are proposed for its characterization and to discriminate adulterated foundation beeswax sheets. The concentrations of many compounds resulted to be statistically different for white and yellow beeswaxes, while the observation of concentrations out of normal in some marketed foundation beeswax sheets suggested their adulteration. However, the measurement of anomalous concentrations in foundation beeswax sheets did not imply necessarily their rejection by the bees.
Inhibition of lipid peroxidation in UVA‐treated skin fibroblasts by luteolin and its glucosides
Authors: Rahimuddin Sawsan A. , Khoja Samir M. , Zuhair Marzoki M. , Howell Nazlin K. , Brown Jonathan E.
Published: June 2007

Ultraviolet A (UVA) radiation causes oxidative damage to human skin cells. This damage may be reduced or prevented using plant compounds as photoprotectants. To investigate the relationship between chemical structure and UVA‐protective activity, three structurally related flavonoids, namely luteolin, luteolin‐7‐O‐glucoside (both present in artichoke) and luteolin‐4'‐O‐glucoside (present in wild carrot), were studied. Human skin fibroblasts exposed to UVA (250 and 500 kJ/m2) were treated with each flavonoid (30 µM) for 18 h prior to irradiation. The extent of lipid peroxidation in the cellular extracts was assessed as lipid peroxides and malondialdehyde (MDA). Luteolin and luteolin‐7‐O‐glucoside both prevented a significant increase in lipid peroxides at 250 kJ/m2, but at 500 kJ/m2 their effectiveness was clearly attenuated. Contrastingly, luteolin‐4'‐O‐glucoside was pro‐oxidant at both radiation doses. Measurements of MDA levels highlighted that luteolin was clearly more effective than the two glucosides at both 250 and 500 kJ/m2. Overall, these results show clear differences between the three flavonoids and suggest that the B ring 3',4'‐dihydroxy group, lacking in luteolin‐4'‐O‐glucoside, may be particularly important. Flavonoid: transition metal ion chelation studies confirmed the influence of the 3',4'‐dihydroxy group, which is also relevant to the quenching of singlet oxygen. These features as well as the greater lipophilic nature of luteolin together explain the superior activity of this flavonoid which may be potentially useful as a supplement in photoprotective skin preparations.
Testing the boolean hypothesis in the non‐convex case when a bounded grain can be assumed
Authors: Chadœuf J. , Bacro J. N. , Thébaud G. , Labonne G.
Published: June 2007

Spatial independence of objects is a strong hypothesis when using boolean models. Methods to test it have then been developed, but only when the objects are convex. We propose here to replace this assumption by a bound assumption of the objects which can be more easily assumed when modeling spatial patterns in ecology and agricultural science. A test is then proposed, based on the length of the voids of the intersection between transect lines and a dilation of the original process related to the bound value. Its application is shown to several examples, together with its extension to an epidemiological case on orchards, where this problem comes from. Copyright © 2007 John Wiley & Sons, Ltd.
Does amplitude scaling of ground motion records result in biased nonlinear structural drift responses?
Authors: Luco Nicolas , Bazzurro Paolo
Published: June 2007

Limitations of the existing earthquake ground motion database lead to scaling of records to obtain seismograms consistent with a ground motion target for structural design and evaluation. In the engineering seismology community, acceptable limits for ‘legitimate’ scaling vary from one (no scaling allowed) to 10 or more. The concerns expressed by detractors of scaling are mostly based on the knowledge of, for example, differences in ground motion characteristics for different earthquake magnitude–distance (Mw–Rclose) scenarios, and much less on their effects on structures. At the other end of the spectrum, proponents have demonstrated that scaling is not only legitimate but also useful for assessing structural response statistics for Mw–Rclose scenarios. Their studies, however, have not investigated more recent purposes of scaling and have not always drawn conclusions for a wide spectrum of structural vibration periods and strengths. This article
investigates whether scaling of records randomly selected from an Mw–Rclose bin (or range) to a target fundamental‐mode spectral acceleration (Sa) level introduces bias in the expected nonlinear structural drift response of both single‐degree‐of‐freedom oscillators and one multi‐degree‐of‐freedom building. The bias is quantified relative to unscaled records from the target Mw–Rclose bin that are ‘naturally’ at the target Sa level. We consider scaling of records from the target Mw–Rclose bin and from other Mw–Rclose bins. The results demonstrate that scaling can indeed introduce a bias that, for the most part, can be explained by differences between the elastic response spectra of the scaled versus unscaled records. Copyright © 2007 John Wiley & Sons, Ltd.
Sequence stratigraphy of the upper Millstone Grit (Yeadonian, Namurian), North Wales
Authors: Jerrett Rhodri M. , Hampson Gary J.
Published: June 2007

The upper Millstone Grit strata (Yeadonian, Namurian) of North Wales have been studied using sedimentological facies analysis and sequence stratigraphy. These strata comprise two cyclothems, each containing prodelta shales (Holywell Shale) that pass gradationally upwards into delta‐front and delta‐plain deposits (Gwespyr Sandstone Formation). The deltas formed in shallow water (<100 m), were fluvial‐dominated, had elongate and/or sheet geometries and are assigned to highstand systems tracts. Two delta complexes with distinctive sandstone petrographies are identified: (1) a southerly derived, quartzose delta complex sourced locally from the Wales‐Brabant Massif, and (2) a feldspathic delta complex fed by a regional source(s) to the north and/or west. The feldspathic delta complex extended further south in the younger cyclothem. A multistorey braided‐fluvial complex (Aqueduct Grit, c. 25 m thick) is assigned to a lowstand systems tract, and occupies an incised valley that was eroded into the highstand feldspathic delta complex in the younger cyclothem. A candidate incised valley cut into the highstand feldspathic delta complex in the older cyclothem is also tentatively identified. Transgressive systems tracts are thin (<5 m) and contain condensed fossiliferous shales (marine bands). The high‐resolution sequence stratigraphic framework interpreted for North Wales can be readily traced northwards into the Central Province Basin (‘Pennine Basin’), supporting the notion that high‐frequency, high‐magnitude sea‐level changes were the dominant control on stratigraphic architecture. Copyright © 2007 John Wiley & Sons, Ltd.
The Atlanta University Center: A consortium‐based dual degree engineering program
Authors: Jackson Marilyn T.
Published: June 2007

This chapter describes the Atlanta University Center's Dual Degree Engineering Program and the model used to increase the number of minorities in engineering, science, and technology through consortia.
Getting on the college track in fifth grade
Authors: Druckman Rosanne
Published: June 2007

The Hartford Consortium for Higher Education has emphasized the issue of college access since 1986 and maintains the importance of also addressing issues that affect the public school system in Hartford, Connecticut.
A university center leverages resources and provides access
Authors: Baus Frederick
Published: June 2007

This chapter reviews the history and impact of a regional center through which seven universities collaborate to serve the educational needs of a major metropolitan area in upstate South Carolina.
Articulating the future through collaboration
Authors: Peterson Lorna M.
Published: June 2007

What collaborations have taught us about cost savings, the advantages of pooling resources, and providing more for less is transferable and can help higher education respond to the needs and challenges of equitable access.
The demand for statin: the effect of copay on utilization and compliance
Authors: Thiebaud Patrick , Patel Bimal V. , Nichol Michael B.
Published: June 2007

Increasing drug costs in the US have prompted employers and insurers alike to turn to higher drug copays for cost containment. The effect of rising copays on compliance with statins (HMG‐CoA reductase inhibitors) treatment has received surprisingly little attention in the applied literature. This paper uses pharmacy claims data from a commercially insured adult population to determine the effect of copay change on compliance at the individual level. Fixed effect logit and Poisson regressions estimate the effect of copays on monthly likelihood of high compliance and average monthly days of supply respectively. Higher copays reduce compliance among statin users, with less compliant patients responding more strongly to copay change than compliant patients. These results suggest that specific financial incentives given to less compliant patients could improve compliance with statin treatment at a relatively low cost. Copyright © 2007 John Wiley & Sons, Ltd.
Application of a Highly Robust and Efficient Fluorescence‐Resonance‐Energy‐Transfer (FRET) System in DNA
Authors: Clima Lilia , Hirtz‐Haag Caroline , Kienzler Andrea , Bannwarth Willi
Published: June 2007

We report a feasibility study for the application of our newly developed highly efficient and robust fluorescence‐resonance‐energy‐transfer (FRET) system to DNA. A 2′‐oligodeoxynucleotide, 12, equipped with a quinolinone derivative as donor and a (bathophenanthroline)ruthenium(II) complex as acceptor and having a single uridine as potential cleavage site under basic conditions revealed an intensive FRET, which almost vanished after cleavage of the oligonucleotide under basic conditions (Fig. 7). Furthermore, in the arrangement of a molecular beacon (MB) DNA (see 13), a significant decrease of the FRET was observed after hybridization to a target sequence (Fig. 9). Due to the long decay times of the fluorescence of the Ru‐complex, the system allows for highly sensitive time‐gated measurements.
Two New Highly Oxidized Humulane Sesquiterpenes from the Basidiomycete Lactarius mitissimus
Authors: Luo Du‐Qiang , Gao Yuan , Yang Xiao‐Long , Tang Jian‐Guo , Zhao Li‐Yan , Liu Ji‐Kai
Published: June 2007

Two new highly oxidized humulane sesquiterpenes, mitissimols F (1) and G (2), were isolated from the fruiting bodies of Lactarius mitissimus. Their structures were elucidated by using extensive spectroscopic techniques including 1D‐ and 2D‐NMR experiments. The absolute configuration of mitissimol F (1) was determined by 1H‐NMR resolution of its diastereoisomeric α‐methoxy‐α‐(trifluoromethyl)benzeneacetates (MTPA). It was shown to be (1S,3E,6S,8R,9R,10S,11R)‐8,9 : 10,11‐diepoxy‐1,6‐dihydroxyhumul‐3‐en‐5‐one (=(1S,2R,4R,6S,8E,11S,12R)‐6,11‐dihydroxy‐1,6,10,10‐tetramethyl‐3,13‐dioxatricyclo[10.1.0.02,4]tridec‐8‐en‐7‐one).
New Diterpene Alkaloids from Aconitum sungpanense var. leucanthum
Authors: Yan Hua , Chen Dong‐Lin , Jian Xin‐Xian , Wang Feng‐Peng
Published: June 2007

Five new C19 diterpene alkaloids, leucanthumsines A (1), B (2), C (3), D (4), and E (5), were isolated from the Chinese medicinal herb Aconitum sungpanense var. leucanthum, together with the known C19 diterpene alkaloids pseudaconine, neoline, 1‐O‐methyldelphisine, crassicaudine, chasmanine, talatisamine, indaconitine, ezochansmanine, and leueantine D. The structures of these new alkaloids were elucidated by HR‐MS and advanced NMR methods, including 1H‐ and 13C‐NMR (DEPT), 1H,1H‐COSY, HMQC, and HMBC experiments.
Pteridines. Part CXVII
Authors: Torigoe Kiyoshi , Kariya Naohiro , Soranaka Kazuyuki , Pfleiderer Wolfgang
Published: June 2007

A series of side chain reactions starting from the 6‐ and 7‐styryl‐substituted 1,3‐dimethyllumazines 1 and 21 as well as from the 6‐ and 7‐[2‐(methoxycarbonyl)ethenyl]‐substituted 1,3‐dimethyllumazine 2 and 22 were performed first by addition of Br2 to the CC bond forming the 1′,2′‐dibromo derivatives 3, 4, 24, and 26 in high yields (Schemes 1 and 3) (lumazine=pteridine‐2,4(1H,3H)‐dione). Treatment of 3 with various nucleophiles gave rise to an unexpected tele‐substitution in 7‐position and elimination of the Br‐atoms generating 7‐alkoxy‐ (see 5 and 6), 7‐hydroxy‐ (see 7) and 7‐amino‐6‐styryl‐1,3‐dimethyllumazines (see 8–11) (Scheme 1). On the other hand, 4 underwent, with dilute DBU (1,8‐diazabicyclo[5.4.0]undec‐2‐ene), a normal HBr elimination in the side chain leading to 18, whereas treatment with MeONa afforded a more severe structural change to 19. Similarly, 24 and 26 reacted to 27, 32, and 33 under mild conditions, whereas in boiling NaOMe/MeOH, 24 gave 7‐(2‐dimethoxy‐2‐phenylethyl)‐1,3‐dimethyllumazine (30) which was hydrolyzed to give 31 (Scheme 3). From the reactions of 4 and 24 with DBU resulted the dark violet substance 20 and 25, respectively, in which DBU was added to the side chain (Scheme 2). The styryl derivatives 1 and 21 could be converted, by a Sharpless dihydroxylation reaction, into the corresponding stereoisomeric 6‐ and 7‐(1,2‐dihydroxy‐2‐phenylethyl)‐1,3‐dimethyllumazines 34–37 (Scheme 4). The dihydroxy compounds 34 and 35 were also acetylated to 38 and 39 which, on catalytic reduction followed by formylation, yielded the diastereoisomer mixtures 40 and 41. Deacetylation to 42 and 45 allowed the chromatographic separation of the diastereoisomers resulting in the isolation of 43 and 44 as well as 46 and 47, respectively. Introduction of a 6‐ or 7‐ethynyl side chains proceeded well by a Sonogashira reaction with 6‐ (48) or 7‐chloro‐1,3‐dimethyllumazine (55) yielding 49–51 and 56–58 (Scheme 5). The direction of H2O addition to the triple bond is depending on the substituents since the 6‐ (49) and 7‐(phenylethynyl)‐1,3‐dimethyllumazine (56) showed attack at the 2′‐position yielding 53 and 60, in contrast to the 6‐ (51) and 7‐ethynyl‐1,3‐dimethyllumazine (58) favoring attack at C(1′) and formation of 6‐ (52) and 7‐acetyl‐1,3‐dimethyllumazine (59).
One‐Pot Three‐Component Synthesis of α‐Amino Nitriles Catalyzed by 2,4,6‐Trichloro‐1,3,5‐triazine (Cyanuric Acid)
Authors: Das Biswanath , Kumar Rathod Aravind , Thirupathi Ponnaboina
Published: June 2007

A simple and efficient method has been developed for the synthesis of α‐amino nitriles from aldehydes, amines and trimethylsilyl cyanide (Me3SiCN) in the presence of a catalytic amount of cyanuric acid at room temperature.
Synthesis, Characterization, Crystal and Molecular Structure of 1,5‐Dihydro‐2H‐cyclopenta[1,2‐b:5,4‐b′]dipyridin‐2‐imine
Authors: Baysal Akın , Durap Feyyaz , Gümgüm Bahattin , Yıldırım Leyla T. , Ülkü Dinçer , Boğa Ayse Dilek , Özkar Saim
Published: June 2007

The reaction of 1,5‐dihydro‐2H‐cyclopenta[1,2‐b:5,4‐b′]dipyridin‐2‐one (3) with an alkylamine (butylamine, hexylamine or ethylenediamine) yields, quite unexpectedly and in the absence of catalyst, the novel compound 1,5‐dihydro‐2H‐cyclopenta[1,2‐b:5,4‐b′]dipyridin‐2‐imine (4) as the sole, analytically pure, solid product, which was fully characterized. The structure of 4 was unequivocally solved by single‐crystal X‐ray‐diffraction analysis. The compound crystallizes in a monoclinic cell (space group P 21/c), with two molecules in the asymmetric unit, held together by intermolecular H‐bonds. Compound 4 could be interesting as a bi‐ or even tridentate ligand, and exhibits a strong fluorescence upon excitation at 310 nm. A mechanism, based on the observed CN bond cleavage, is proposed.
New Sesterterpenoids from the Marine Sponge Phyllospongia papyracea
Authors: Lan Wen‐Jian , Li Hou‐Jin
Published: June 2007

Chemical investigation of an extract of the marine sponge Phyllospongia papyracea, collected from the South China Sea, led to the isolation and identification of three new scalarane‐type sesterterpenoids, compounds 1–3. Their structures were elucidated by spectroscopic methods, including 1D‐ and 2D‐NMR as well as high‐resolution ESI‐MS experiments. (12α,16β)‐12‐Acetoxy‐16‐hydroxy‐20,24‐dimethyl‐25‐norscalar‐17‐en‐24‐one (1) was cytotoxic against the leukemia P388 cancer cell line, with an IC50 value of 5 μg/ml.
Acetaldehyde accumulation in rat mammary tissue after an acute treatment with alcohol
Authors: Castro G. D. , Layño A. M. A. Delgado de , Fanelli S. L. , Maciel M. E. , Gómez M. I. Díaz , Castro J. A.
Published: June 2007

Previous studies reported the presence in rat mammary tissue of a cytosolic xanthine oxidoreductase pathway for the metabolism of alcohol to acetaldehyde and hydroxyl radicals and to the microsomal biotransformation of ethanol to acetaldehyde. It was also reported that after chronic ethanol drinking stressful oxidative conditions can be observed. The present work reports that even after single doses of ethanol, given at three different levels (6.3 g kg−1; 3.8 g kg−1 or 0.6 g kg−1 p.o.), acetaldehyde accumulates for prolonged periods of time in the mammary tissue to reach concentrations higher than in blood (e.g. 5.1 ± 1.2 nmol g−1 versus 0.2 ± 0.1 nmol ml−1, for 6.3 g kg−1 dose, 6 h after intoxication). The presence in rat mammary tissue of low activities of additional enzymes able to generate acetaldehyde was established (alcohol dehydrogenase: 0.97 ± 0.84 mU mg−1 protein; CYP2E1: 1.30 ± 0.12 × 10−2 pmol 4‐nitrocatechol min−1 mg−1 protein) and a low activity of aldehyde dehydrogenase was observed in the cytosolic, mitochondrial and microsomal fractions (0.02 ± 0.04; 0.35 ± 0.09 and 0.72 ± 0.19 mU mg−1 protein, respectively). After a single high dose of ethanol, an increased susceptibility to oxidative stress was observed, as evidenced by changes in the shape of t‐butylhydroperoxide induced emission of chemiluminescence in mammary tissue (6.3 g kg−1 dose; at 3 and 6 h). In summary, the results show that even after single doses of ethanol, acetaldehyde, either formed in situ or arriving via blood, tends to accumulate in mammary tissue and that this condition might decrease cell defenses against injury. Copyright © 2007 John Wiley & Sons, Ltd.
Organic chemical reaction mechanisms clarified for deuterium‐ and carbon‐13‐labeled hydrocarbons
Authors: Baldwin John E.
Published: June 2007

Questions bearing on just how organic chemical structures are converted to other compounds can be addressed in numerous ways through syntheses and studies of appropriately designed stable–isotope‐labeled analogs. Most of the examples in the present review summarize studies of various thermal isomerizations and fragmentations that have provided information on mechanistic details, determinations of reaction stereochemistry, tests for possible interventions of short‐lived reaction intermediates, and relevant checks of theory‐based predictions and rationalizations. Such work serves either to reinforce generally accepted conceptual constructs for posited reaction mechanisms or to prompt reinterpretations of imperfect mechanistic understandings, as the experimental findings may require. Copyright © 2007 John Wiley & Sons, Ltd.
Price rigidities, inventories, and growth fluctuations
Authors: Tsoukis Chris , Naqvi Naveed
Published: June 2007

We investigate the interactions of price rigidities and storability of goods, and their implications for inflation and growth. The model is an optimising, stochastic general equilibrium one, featuring endogenous growth, the possibility of (short run) excess demand and inflation derived from sluggish and staggered price setting (a version of the ‘New Keynesian Phillips Curve’). Analytical short‐run dynamics are derived. A notable feature is the predicted short‐run comovements between growth and inflation (negative) and between the inventory ratio and growth (positive). Increased price flexibility reduces the persistence of the system but its overall influence on variances is uncertain. Copyright © 2007 John Wiley & Sons, Ltd.
Warranties as a device to extract rent from low‐risk users of a product
Authors: Hakes David , Shin Dongsoo
Published: June 2007

We develop a simple model that provides a new rationale for why a monopolist should bundle its product with a warranty even when all parties are risk neutral. In our model, a risk‐neutral monopolist faces two types of risk‐neutral consumers—low‐risk users that are unlikely to cause product failure and high‐risk users that are more likely to cause product failure. We find that when the firm fails to provide a warranty, a low‐risk user acquires a strictly positive rent by pretending to be a high‐risk user and receiving a price discount. By imposing a warranty, however, the monopolist can increase the price to high‐risk users, which in turn removes the incentive for a low‐risk user to pretend to be a high‐risk user, and the firm successfully extracts rent from the low‐risk user. Copyright © 2007 John Wiley & Sons, Ltd.
Botulinum toxin type B (Myobloc®) in subjects with hemifacial spasm: Results from an open‐label, dose‐escalation safety study
Authors: Trosch Richard M. , Adler Charles H. , Pappert Eric J.
Published: June 2007

Ojbective

Evaluate the safety of botulinum toxin type B (BoNT‐B) in subjects with hemifacial spasm (HFS).

Methods

This open‐label, sequential dose‐escalation study evaluated BoNT‐B in subjects with HFS. Eligible subjects were enrolled and received a single injection of one of four sequential BoNT‐B doses (100, 200, 400, or 800 U). Following injection, subjects were evaluated in person at Weeks 2 and 8 and by phone at Weeks 1, 4, and 10 and every 2 weeks thereafter until benefit was lost. Safety was assessed by adverse events (AEs), vital signs and clinical laboratory evaluation. The severity of HFS was assessed using a patient social impairment visual analog scale (VAS), subject severity of contraction VAS, the HFS physician assessment, and subject HFS frequency and severity assessment.

Results

Nineteen predominately Caucasian (92%) and female (67%) subjects (aged 36–80 years) with HFS participated in this study. Subjects remained in the study an average of 88 days (range of 41–332 days) after receiving a single dose of BoNT‐B. No deaths, serious AEs or AEs leading to trial discontinuation occurred during the study period. Two subjects in the 400 U dose group requested early withdrawal, whereas all other subjects completed the study. A reduction in HFS severity was observed in subjects treated with doses of 200 U or more. Improvements in subject HFS assessments tended to return to baseline values by 8 weeks following injection.

Conclusion

BoNT‐B was well‐tolerated and reduced HFS severity in subjects who received injections of 200 to 800 U. Additional investigation is necessary to confirm the findings from this open‐label study. © 2007 Movement Disorder Society
Asymmetrical ventricular enlargement in Parkinson's disease
Authors: Huang Xuemei , Lee Yueh Z. , McKeown Martin , Gerig Guido , Gu Hongbin , Lin Weili , Lewis Mechelle M. , Ford Sutapa , Tröster Alexander I. , Weinberger Daniel R. , Styner Martin
Published: June 2007

Parkinson's disease (PD) typically manifests with asymmetric motor symptom onset. Ventricular enlargement, a nonspecific measure of brain atrophy, has been associated with cognitive decline in PD, but not with motor symptom asymmetry. Asymmetrical ventricular enlargement on magnetic resonance images was explored in a monozygotic twin pair discordant for PD and in nine healthy monozygotic twin pairs. The left–right lateral ventricular volumetric difference of the PD‐twin was greater than that of his twin and all other healthy twins, with the larger ventricle observed contralateral to the more symptomatic side. Moreover, the lateral ventricle asymmetry difference between twin pairs was significantly higher for the discordant PD‐twin pair than for the healthy twin pairs. This is the first report to suggest the presence of asymmetrical ventricular enlargement in PD, findings that may be worthy of further study. © 2007 Movement Disorder Society
Midbrain transcranial sonography in Korean patients with Parkinson's disease
Authors: Kim Ji Youn , Kim Seong Tae , Jeon Seong Hee , Lee Won Yong
Published: June 2007

Transcranial sonography (TCS) is potentially useful for the diagnosis of Parkinson's disease (PD). However, studies on TCS have so far been restricted to European populations. To investigate the efficacy of TCS in Korean PD patients and its correlation with the clinical features, we carried out midbrain TCS in 43 PD patients and 35 normal controls and evaluated the area of the substantia nigra (SN) hyperechogenicity and its ratio to the area of the whole midbrain. In 16 subjects (21%), TCS was unsuccessful due to insufficient acoustic temporal bone windows. The mean area of bilateral SN hyperechogenicity and its ratio to the midbrain area were greater in the PD patients than that in the controls (P < 0.01). In the PD patients, the area of SN hyperechogenicity and its ratio to the individual midbrain area were moderately correlated with the PD duration (r = 0.526 and 0.536, P = 0.01, respectively) but not with the age, UPDRS motor scores or H‐Y stage. There was no difference in the SN hyperechogenicity between the tremor‐dominant, akinetic‐rigid, and mixed‐type PD patients. In conclusion, midbrain TCS is an effective diagnostic tool for detecting PD in the Korean population. However, it does not reflect the severity or phenotypes of parkinsonism. © 2007 Movement Disorder Society
Progressive muscle atrophy with hypokalemic periodic paralysis and calcium channel mutation
Authors: Meyer Thomas , Jurkat‐Rott Karin , Huebner Angela , Lehmann‐Horn Frank , Linke Peter , Van Landeghem Frank , Dullinger Jörn S. , Spuler Simone
Published: June 2007

A family with hypokalemic periodic paralysis (HypoPP) and motor neuron degeneration is reported. In conjunction with HypoPP, the index patient developed progressive muscle atrophy. The calcium channel gene CACNA1S showed a mutation encoding p.R528H, which has been related previously to HypoPP. We propose that CACNA1S mutations may comprise a previously unrecognized genetic risk factor in a greater spectrum of motor unit disorders including amyotrophic lateral sclerosis. Muscle Nerve, 2007
Prognostic values of electrodiagnostic studies in traumatic radial neuropathy
Authors: Malikowski Thu , Micklesen Paula J. , Robinson Lawrence R.
Published: June 2007

It is important to have strong predictors of outcome in traumatic neuropathies so that appropriate management can be instituted early. Our objective in this study was to evaluate the prognostic value of electrodiagnostic studies in traumatic radial neuropathy. In this retrospective study, 33 of 67 subjects with traumatic radial neuropathy met the inclusion criteria. Good outcome was defined as grade 3 or higher strength on the Medical Research Council scale in wrist extensors. Compound muscle action potential (CMAP) responses from extensor indicis proprius (EIP) predicted prognosis: 92% of subjects with a recordable CMAP had a good outcome; and 65% of those with an absent response had a good outcome. Recruitment in brachioradialis was also predictive: 92% of those with full, central, or reduced recruitment had a good outcome; 67% of those with discrete recruitment had a good outcome; and only 33% of those with absent recruitment had a good outcome. Studies performed more than 3 months after injury produced more prognostic certainty than those performed earlier. We conclude that electrodiagnostic studies produce useful prognostic information in traumatic radial neuropathy. It is noteworthy, however, that 65% of subjects with an absent radial CMAP (suggesting complete or nearly complete axon loss) still have a good outcome. Muscle Nerve, 2007