bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis and properties of ethylene‐substituted styrene copolymers
Authors: Naga Naofumi , Wakita Yusuke , Murase Shigemitsu
Published: September 2008

The copolymerization of ethylene and substituted styrenes [RSt's; p‐methylstyrene (MSt), p‐tert‐butylstyrene (BSt), 2‐vinylnaphthalene (VN), and p‐(tert‐butyldimethylsilyloxy)styrene (BMSiOSt)] were investigated with dimethylsilylene(tetramethylcyclopentadienyl)(N‐tert‐butyl)titanium dichloride to yield the corresponding ethylene–RSt copolymers. The substituent on the styrene (St) monomers did not affect the monomer reactivity ratio. The effect of the substituent structure of RSt on the thermal and mechanical properties was studied with differential scanning calorimetry, dynamic mechanical thermal spectroscopy, and elongation testing. The glass‐transition temperature (Tg) of the copolymers increased with increasing RSt content, and the order of Tg was as follows: BSt > VN > MSt = St. A copolymer with p‐hydroxystyrene (HOSt) was successively synthesized by means of deprotection of the copolymer with BMSiOSt. The copolymer showed a much higher Tg than the other copolymers because of the hydrogen connection of its OH groups. The mechanical properties of the copolymer in the glass state, at a lower temperature than Tg, were almost independent of the nature of the RSt. The substituent of the St monomers affected the pattern of the stress–strain curve in the elongation testing in the amorphous state. An improvement in the shape memory effect was observed in poly(ethylene‐co‐BSt). © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Semi‐IPN asymmetric membranes based on polyether imide (ULTEM) and polyethylene glycol diacrylate for gaseous separation
Authors: Saimani Sundar , Kumar Ashwani
Published: September 2008

Semi‐interpenetrating polymer networks (semi‐IPN) formed with commercial polyether imide (ULTEM®, PEI) and poly (ethylene glycol) diacrylate (PEGDA) were used to make asymmetric membranes. The effect of increasing amount of PEGDA on the bulk and the gas separation properties of semi‐IPN membranes were studied. The formation of IPNs was confirmed by Fourier Transform Infra Red (FT‐IR) spectroscopy. The 5% weight loss temperature decreased and the percent weight loss of the first step increased with increase in the PEGDA content, which indicated the incorporation of more poly (ethylene glycol) (PEG) segments to the semi‐IPNs. The microscopic experiments revealed the change in morphology with change in PEGDA content. The Scanning electron micrographs exhibited typical finger‐like voids in the sub layer, which is characteristic morphology of asymmetric membranes. The increase in PEGDA content up to 5.7 wt % increased the CO2/N2 selectivity of the semi‐IPN after which the selectivity decreased and permeance increased. Although, the increase in the polar poly (ethylene glycol) molecules is expected to render better CO2 selectivity, the performance of the membrane was found to decrease as PEGDA content exceeded 5.7% for the given ratio. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Kinetic evaluation of tin‐POMS catalyst for urethane reactions
Authors: Wang Wenshou , Wiggins Jeffrey S.
Published: September 2008

We report the activity for a new tin‐polyhedral oligomeric metal silsesquioxane (POMS) catalyst in 1‐butanol and 2‐butanol model reactions with 4,4′‐methylenebis(cyclohexylisocyanate) (H12MDI) in toluene and N,N‐dimethylformamide (DMF). Kinetic rate constants for varying levels of tin‐POMS ranging between 100 ppm and 1000 ppm tin are reported. We observed urethane reactions in toluene to follow second order reaction kinetics, whereas similar reactions in DMF followed first order reaction kinetics. We determined tin‐POMS is an efficient catalyst system for urethane reactions and found the new catalyst to be easy to handle, soluble, and very effective for catalyzing urethane reactions. By direct comparison of a model reaction between tin‐POMS and dibutyltin dilaurate (DBTDL), tin‐POMS was found to be quite similar to DBTDL for urethane catalytic activity. In addition, we show the efficacy for tin‐POMS to be an excellent polyurethane reaction catalyst through a model reaction of H12MDI with 2000 g/mol poly(ε‐caprolactone) diol. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Synthesis of poly(paraphenylene vinylene)—polystyrene‐based rod‐coil block copolymer by atom transfer radical polymerization: Toward a self‐organized lamellar semiconducting material
Authors: Brochon Cyril , Sary Nicolas , Mezzenga Raffaele , Ngov Chheng , Richard Fanny , May Michaël , Hadziioannou Georges
Published: September 2008

Atom transfer radical polymerization (ATRP) was used as a versatile route to well‐defined poly(diethylhexyl‐p‐phenylenevinylene‐b‐styrene) (PPV‐b‐PS) semiconducting block copolymers. For this purpose, original conjugated macroinitiators were synthesized from DEH‐PPV and further used for the copolymerization reaction. The microphase‐separated morphologies obtained with the semiconducting PPV‐b‐PS block copolymer fulfill the basic structural requirements required to build efficient organic photovoltaic devices. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Preparation and characterization of degradation tunable poly(ε‐caprolactone) using a Sn(Oct)2/BF3 dual catalyst
Authors: Jiang G. , Jones I. A. , Rudd C. D. , Walker G. S.
Published: September 2008

Tailoring the degradation rate of poly(ε‐caprolactone) (PCL) was found to be easily accomplished by the polymerization of ε‐caprolactone using a Sn(Oct)2/BF3 dual catalyst. The resulting PCL contained BF3, which acts as a hydrolytic degradation catalyst for PCL. The degradation rate of the polymer was controlled by the concentration of BF3 in the polymer matrix. At lower BF3 concentrations (<0.002 mol dm−3), the degradation rate was linearly proportional to the BF3 concentration. At higher BF3 concentrations, the degradation rate rapidly increased, significantly deviating from the linear relationship between degradation rate and BF3 concentration. The system was found to be very versatile, producing PCL with degradation rates ranging from a half‐life of 0.9–46 weeks. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Synthesis and characterization of the two novel liquid crystalline epoxy resins based on bisphenol‐s mesogen
Authors: Huo Li , Gao Jungang , Du Yonggang , Chai Zhihua
Published: September 2008

Two novel liquid crystalline epoxy resins (LCER) based on bisphenol‐S mesogen, 4,4′‐Bis‐(2,3‐epoxypropyloxy)‐sulfonyl bis(1,4‐phenylene) (p‐BEPSBP) and sulfonyl bis(4,1‐phenylene) bis[4‐(2,3‐epoxypropyloxy)benzoate] (p‐SBPEPB), were synthesized. Their liquid crystalline behavior and structure were characterized by Fourier transmittance infrared ray (FTIR), differential scanning calorimetry (DSC), 1HNMR, polarized optical microscopy (POM) and X‐ray diffraction (XRD). The results show that p‐BEPSBP is a kind of thermotropic liquid crystal and has a smectic mesophase with a melting point (Tm) at 165°C; the p‐SBPEPB is a kind of nematic mesophase with the temperature range of 155–302°C from the Tm to the clearing point Ti. The curing behaviors and texture of the liquid crystalline epoxy resins with 4,4′‐diaminodiphenyl ether (DDE) were also studied by DSC and some kinetic parameters were evaluated according to the Ozawa's method. The dynamic mechanical properties of curing products were also investigated by torsional braid analysis (TBA), and the results suggest that the dynamic mechanical loss peak temperature (Tp) of p‐BEPSBP/DDE and p‐SBPEPB/DDE is 120 and 130°C, respectively. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Synthesis and properties of electrically‐sensitive poly(acrylic acid‐co‐acetoacetoxy ethyl methacrylate) gels
Authors: Jin Xiachao , Kang Hongmei , Huang Yongmin , Liu Honglai , Hu Ying
Published: September 2008

A series of electric field sensitive copolymer P(AA‐co‐AAEM) gels of acrylic acid (AA) with acetoacetoxy ethyl methacrylate (AAEM) were prepared by free‐radical copolymerization, with N,N′‐methylene bisacrylamide (MBAAm) and ammounium persulfate (APS) as crosslinking agent and initiator, respectively. The structures and properties of the gels were tunable by changing the monomer feed weighty ratio (R) (R = WAAEM/(WAAEM + WAA) of AAEM and AA. The influences of the NaCl concentration and pH buffer solutions on the equilibrium swelling ratios of the gels were studied in detail. It is shown that both NaCl concentration and pH value of the buffer solution affect the swelling properties of the P(AA‐co‐AAEM) gels greatly. Moreover, the gel deswelling behavior induced by a direct current electric field was investigated and an excellent electric‐sensitivity was found. Among all the samples, the gel with monomer feed weighty ratio (R) = 0.1479 showed the best electrical contraction properties. On the basis of the experimental results, the mechanism of the electricity‐induced deswelling behavior was presented. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Polystyrene composites containing crosslinked polystyrene‐multiwalled carbon nanotube balls
Authors: Kwon Soon‐Min , Kim Hun‐Sik , Kim Don‐Young , Yun Young Soo , Jin Hyoung‐Joon
Published: September 2008

Crosslinked polystyrene‐multiwalled carbon nanotube (PS‐MWCNT) balls, which act as conductive microfillers, were prepared by the in situ suspension polymerization of styrene with MWCNTs and divinyl benzene (DVB) as a crosslinking agent. The diameters of the synthesized crosslinked PS‐MWCNT balls ranged from 10 to 100 μm and their electrical conductivity was about 7.7 × 10−3 S/cm. The morphology of the crosslinked PS‐MWCNT balls was observed by scanning electron microscopy and transmission electron microscopy. The change in the chemical structure of the MWCNTs was confirmed by Raman spectroscopy and Fourier transform infrared spectroscopy. The mechanical and electrical properties of the PS/crosslinked PS‐MWCNT ball composites were investigated. It was found that the tensile strength, ultimate strain, Young's modulus, and impact strength of the PS matrix were enhanced by the incorporation of the crosslinked PS‐MWCNT balls. In addition, the mechanical properties of the PS/crosslinked PS‐MWCNT ball composites were better than those of the PS/pristine MWCNT composites. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Natural language processing versus content‐based image analysis for medical document retrieval
Authors: Névéol Aurélie , Deserno Thomas M. , Darmoni Stéfan J. , Güld Mark Oliver , Aronson Alan R.
Published: September 2008

One of the most significant recent advances in health information systems has been the shift from paper to electronic documents. While research on automatic text and image processing has taken separate paths, there is a growing need for joint efforts, particularly for electronic health records and biomedical literature databases. This work aims at comparing text‐based versus image‐based access to multimodal medical documents using state‐of‐the‐art methods of processing text and image components. A collection of 180 medical documents containing an image accompanied by a short text describing it was divided into training and test sets. Content‐based image analysis and natural language processing techniques are applied individually and combined for multimodal document analysis. The evaluation consists of an indexing task and a retrieval task based on the “gold standard” codes manually assigned to corpus documents. The performance of text‐based and image‐based access, as well as combined document features, is compared. Image analysis proves more adequate for both the indexing and retrieval of the images. In the indexing task, multimodal analysis outperforms both independent image and text analysis. This experiment shows that text describing images can be usefully analyzed in the framework of a hybrid text/image retrieval system.
Protein inheritance (prions) based on parallel in‐register β‐sheet amyloid structures
Authors: Wickner Reed B. , Shewmaker Frank , Kryndushkin Dmitry , Edskes Herman K.
Published: September 2008

Most prions (infectious proteins) are self‐propagating amyloids (filamentous protein multimers), and have been found in both mammals and fungal species. The prions [URE3] and [PSI+] of yeast are disease agents of Saccharomyces cerevisiae while [Het‐s] of Podospora anserina may serve a normal cellular function. The parallel in‐register beta‐sheet structure shown by prion amyloids makes possible a templating action at the end of filaments which explains the faithful transmission of variant differences in these molecules. This property of self‐reproduction, in turn, allows these proteins to act as de facto genes, encoding heritable information. BioEssays 30:955–964, 2008. © 2008 Wiley Periodicals, Inc.
Feedback‐mediated neuronal competition for survival cues regulates innervation of a target tissue
Authors: Li Yang , Fivaz Marc
Published: September 2008

Proper wiring of the nervous system requires tight control of the number of nerve terminals that innervate a target tissue. Recent work by Deppmann et al.,1 now suggests that this is achieved by feedback‐mediated neuronal competition for target‐derived survival cues. The authors' model is inspired by the theory for pattern formation based on self‐activation and lateral inhibition, proposed by Meinhardt and Gierer more than 30 years ago.2 BioEssays 30:929–933, 2008. © 2008 Wiley Periodicals, Inc.
Matchmaking, metrics and money: a pathway to progress in translational research
Authors: Krontiris Theodore G. , Rubenson David
Published: September 2008

In the 24 years since the founding of BioEssays, the level of translational research, as well as the expectations for its success, have burgeoned. Based on our analysis of current and projected US efforts to establish effective centers of translational research, our own institutional experience and discussions with academic research center leaders and institutional research executives, we have arrived at several critical conclusions about how best to foster disease‐based research on the institutional, national and international level, what summary statistics may best serve as a measurement of successful practice, roughly how much more money will be required to fund the ongoing venture in the US and how to organize and promote this vision. BioEssays 30:1025–1029, 2008. © 2008 Wiley Periodicals, Inc.
Fluorescence quenching and bonding properties of some hydroxamic acid derivatives by iron(III) and manganese(II)
Authors: Senthilnithy R. , De Costa M. D. P. , Gunawardhana H. D.
Published: September 2008

Spectrophotometric investigations of highly fluorescent metal chelating molecules are of relevance due to their potential application in novel, selective fluorescence‐based sensors. Benzene and naphthalene chromophores are highly fluorescent while hydroxamic acids are widely used as ligands for complexation of transition metals. In order to develop fluorescence probes, several phenyl derivatives of N‐phenylbenzohydroxamic acid and an aminodihydroxamic acid linked with a naphthalene chromophore were synthesized and their selective ionophoric properties towards iron(III) and manganese(II) ions were investigated using fluorescence and absorption spectroscopy. Both methods confirm the formation of 1:1 and 1:2 complexes for iron(III) and a 1:1 complex for manganese(II). The complex that is formed depends on the concentration of the ligand and pH of the medium. The amino dihydroxamic acid exhibits a prominent selectivity towards iron(III) with a two‐step 1:1 and 1:2 quenching mechanism at pH 3 and towards manganese(II) with a 1:1 quenching mechanism at a probe concentration of 1 × 10−5 mol dm−3 at pH 9.5 The logarithm of overall formation constants of 1:1 and 1:2 complexes of iron(III) were estimated as 3.30 and 9.05, respectively. Copyright © 2008 John Wiley & Sons, Ltd.
The effect of hydroxylamine on the activity and aggregate structure of autotrophic nitrifying bioreactor cultures
Authors: Harper Willie F. , Terada Akihiko , Poly Franck , Le Roux Xavier , Kristensen Ken , Mazher Mustafa , Smets Barth F.
Published: September 2008

Addition of hydroxylamine (NH2OH) to autotrophic biomass in nitrifying bioreactors affected the activity, physical structure, and microbial ecology of nitrifying aggregates. When NH2OH is added to nitrifying cultures in 6‐h batch experiments, the initial NH3‐N uptake rates were physiologically accelerated by a factor of 1.4–13. NH2OH addition caused a 20–40% decrease in the median aggregate size, broadened the shape of the aggregate size distribution by up to 230%, and caused some of the microcolonies to appear slightly more dispersed. Longer term NH2OH addition in fed batch bioreactors decreased the median aggregate size, broadened the aggregate size distribution, and decreased NH3‐N removal from >90% to values ranging between 75% and 17%. This altered performance is explained by quantitative fluorescence in situ hybridization (FISH) results that show inhibition of nitrifying populations, and by qPCR results showing that the copy numbers of amoA and nxrA genes gradually decreased by up to an order‐of‐magnitude. Longer term NH2OH addition damaged the active biomass. This research clarifies the effect of NH2OH on nitrification and demonstrates the need to incorporate NH2OH‐related dynamics of the nitrifying biomass into mathematical models, accounting for both ecophysiological and structural responses. Biotechnol. Bioeng. 2009; 102: 714–724. © 2008 Wiley Periodicals, Inc.
In situ 2D fluorometry and chemometric monitoring of mammalian cell cultures
Authors: Teixeira Ana P. , Portugal Carla A.M. , Carinhas Nuno , Dias João M.L. , Crespo João P. , Alves Paula M. , Carrondo M.J.T. , Oliveira Rui
Published: September 2008

The main objective of the present study was to investigate the use of in situ 2D fluorometry for monitoring key bioprocess variables in mammalian cell cultures, namely the concentration of viable cells and the concentration of recombinant proteins. All studies were conducted using a recombinant Baby Hamster Kidney (BHK) cell line expressing a fusion glycoprotein IgG1‐IL2 cultured in batch and fed‐batch modes. It was observed that the intensity of fluorescence signals in the excitation/emission wavelength range of amino acids, vitamins and NAD(P)H changed along culture time, although the dynamics of single fluorophors could not be correlated with the dynamics of the target state variables. Therefore, multivariate chemometric modeling was adopted as a calibration methodology. 2D fluorometry produced large volumes of redundant spectral data, which were first filtered by principal components analysis (PCA). Then, a partial least squares (PLS) regression was applied to correlate the reduced fluorescence maps with the target state variables. Two validation strategies were used to evaluate the predictive capacity of the developed PLS models. Accurate estimations of viable cells density (r2 = 0.95; 99.2% of variance captured in the training set; r2 = 0.91; 97.7% of variance captured in the validation set) and of glycoprotein concentration (r2 = 0.99 and 99.7% of variance captured in the training set; r2 = 0.99 and 99.3% of variance captured in the validation set) were obtained over a wide range of reactor operation conditions. The results presented herein confirm that 2D fluorometry constitutes a reliable methodology for on‐line monitoring of viable cells and recombinant protein concentrations in mammalian cell cultures. Biotechnol. Bioeng. 2009;102: 1098–1106. © 2008 Wiley Periodicals, Inc.
Using FRET to measure the angle at which a protein bends DNA
Authors: Kugel Jennifer F.
Published: September 2008

An undergraduate biochemistry laboratory experiment that will teach the technique of fluorescence resonance energy transfer (FRET) while analyzing protein‐induced DNA bending is described. The experiment uses the protein TATA binding protein (TBP), which is a general transcription factor that recognizes and binds specific DNA sequences known as TATA boxes. When TBP binds to a TATA box, it bends the DNA. Such bending will be detected using FRET to measure the distance between two fluorophores located on the ends of the DNA. When TBP binds and bends the DNA, the fluorophores move closer together, reflected by an increase in FRET. At the completion of the experiment, three parameters will be determined: 1) the efficiency of the FRET, 2) the end‐to‐end distance between the fluorophores, and 3) the angle at which TBP bends the DNA. In performing this experiment, students will be introduced to FRET, gain experience in quantitative biophysical measurements, and appreciate how a protein can induce a dramatic change in DNA conformation.
Phosphoenolpyruvate
Authors: Behrman E. J. , Gopalan V.
Published: September 2008

The conversion of phosphoenolpyruvate (PEP) in glycolysis is coupled with the formation of ATP. This note discusses the origin of the energy required for ATP formation as arising from redistribution of energy in PEP when compared with its precursor, 2‐phosphoglycerate.
Teaching glycoproteins with a classical paper: Knowledge and methods in the course of an exciting discovery
Authors: Zhu Lixin
Published: September 2008

To integrate research into the teaching of glycoproteins, the story of discovering hydrogen‐potassium ATPase (HK‐ATPase) β subunit is presented in a way covering all the important teaching points. The interaction between the HK‐ATPase α subunit and a glycoprotein of 60–80 kDa was demonstrated to support the existence of the β subunit. On revealing the strategies and experimental designs of this discovery, the knowledge of glycoproteins is delivered. The purpose of this effort was to facilitate the teaching of scientific thinking in the science classroom, to make the biochemistry classroom a more interesting place, and to attract uncertain minds into the career of biochemistry research.
Biotinylated Bi‐ and Tetra‐antennary Glycoconjugates for Escherichia coli Detection
Authors: Hatch Duane M. , Weiss Alison A. , Kale Ramesh R. , Iyer Suri S.
Published: September 2008

Glycans cover the surface of all mammalian cells. Several toxins and pathogens use these glycans to bind and infect the cell. Using a versatile modular synthetic strategy, we have developed biotinylated bi‐ and tetraantennary glycoconjugates to capture and detect E. coli and compared the capturing ability of these molecules to commercial polyclonal antibodies. Magnetic beads were coated with biotinylated glycoconjugate or antibody, and these beads were used to capture, isolate, and quantify bacterial recovery by using a luminescence assay. The glycoconjugate‐coated magnetic beads outperformed antibody‐coated magnetic beads in sensitivity and selectivity when compared under identical experimental conditions. Glycoconjugates could capture Escherichia coli from stagnant water, and the ability of a panel of glycoconjugates to capture a selection of pathogenic bacteria was also evaluated. To the best of our knowledge, this study represents the first comprehensive study that compares synthetic glycoconjugates and antibodies for E. coli detection. The glycoconjugates are also very stable and inexpensive. The results presented here are expected to lead to an increased interest in developing glycoconjugate‐based high affinity reagents for diagnostics.
Resin‐Bound Aminofluorescein for C‐Terminal Labeling of Peptides: High‐Affinity Polarization Probes Binding to Polyproline‐Specific GYF Domains
Authors: Uryga‐Polowy Viviane , Kosslick Daniela , Freund Christian , Rademann Jörg
Published: September 2008

A polymer support for the solid‐phase synthesis of C‐terminally labeled carboxylic acids has been developed. Fluorophore‐labeled peptides were constructed directly on the amino group of resin‐bound aminofluorescein. Fmoc‐protected aminofluorescein was coupled onto tritylpolystyrene, and the free phenolic hydroxyl positions of the fluorescein were blocked with suitable protecting groups. The mode of attachment was analyzed and found to be selective for the phenoxy ether linkage. The conditions for peptide synthesis on the labeling resin were investigated, and a small library of C‐terminally labeled peptides was prepared. The fluorescence quantum yields of C‐terminally labeled peptides were determined and indicated the suitability of the compounds for imaging and binding experiments. The obtained peptides were therefore investigated as fluorescence polarization probes. Two different proline‐rich binding domains of the GYF family—CD2BP2 and PERQ2—were targeted by peptides labeled either C‐ or N‐terminally. Reversible binding constants were determined by fluorescence polarization measurements and were verified by competition experiments with the corresponding unlabeled peptide. As a second control, the binding constants were measured by NMR titration experiments, recording the HSQC NMR spectra of 15N‐labeled proteins in the presence of the peptide polarization probes. Ligands with higher affinities than all others known previously were identified for both GYF domains. The competition assay with the developed fluorescent probe has a high statistical reliability and can thus be used for screening of GYF domain inhibitors.
The Extended View on the Empty C2(3)‐C82 Fullerene: Isolation, Spectroscopic, Electrochemical, and Spectroelectrochemical Characterization and DFT Calculations
Authors: Zalibera Michal , Popov Alexey A. , Kalbac Martin , Rapta Peter , Dunsch Lothar
Published: September 2008

An extended study of the spectroscopic and redox properties of the C82 fullerene is presented. Among the nine isolated‐pentagon‐rule (IPR) isomers of the C82 fullerene the C82(3) isomer with C2 symmetry is the only stable, empty fullerene structure formed in the arc burning process that can be isolated in an isomerically pure form. Here, its formation and isolation are described and its structure is confirmed by experimental spectroscopic studies as well as time‐dependent DFT calculations. The electrochemistry of the C82(3) isomer is studied in detail by cyclic voltammetry and spectroelectrochemistry. The anionic species of C82 with the charge ranging from C82− to C824− were successively generated in o‐dichlorobenzene solution at room temperature and characterized by in situ ESR and visible/near‐infrared (Vis/NIR) spectroscopy. The data give new insights into the charged states of the C82(3) fullerene.
Comparison of the Surprising Metal‐Ion‐Binding Properties of 5‐ and 6‐Uracilmethylphosphonate (5Umpa2− and 6Umpa2−) in Aqueous Solution and Crystal Structures of the Dimethyl and Di(isopropyl) Esters of H2(6Umpa)
Authors: Freisinger Eva , Griesser Rolf , Lippert Bernhard , Moreno‐Luque Cristóbal F. , Niclós‐Gutiérrez Juan , Ochocki Justyn , Operschall Bert P. , Sigel Helmut
Published: September 2008

5‐ and 6‐Uracilmethylphosphonate (5Umpa2− and 6Umpa2−) as acyclic nucleotide analogues are in the focus of anticancer and antiviral research. Connected metabolic reactions involve metal ions; therefore, we determined the stability constants of M(Umpa) complexes (M2+=Mg2+, Ca2+, Mn2+, Co2+, Cu2+, Zn2+, or Cd2+). However, the coordination chemistry of these Umpa species is also of interest in its own right, for example, the phosphonate‐coordinated M2+ interacts with (C4)O to form seven‐membered chelates with 5Umpa2−, thus leading to intramolecular equilibria between open (op) and closed (cl) isomers. No such interaction occurs with 6Umpa2−. In both M(Umpa) series deprotonation of the uracil residue leads to the formation of M(Umpa−H)− complexes at higher pH values. Their stability was evaluated by taking into account the fact that the uracilate residue can bind metal ions to give M2(Umpa−H)+ species. This has led to two further important insights: 1) In M(6Umpa−H)${{{- \hfill \atop {\rm cl}\hfill}}}$ the H+ is released from (N1)H, giving rise to six‐membered chelates (degrees of formation of ca. 90 to 99.9 % with Mn2+, Co2+, Cu2+, Zn2+, or Cd2+). 2) In M(5Umpa−H)${{{- \hfill \atop {\rm cl}\hfill}}}$ the (N3)H is deprotonated, leading to a higher stability of the seven‐membered chelates involving (C4)O (even Mg2+ and Ca2+ chelates are formed up to ≈50 %). In both instances the M(Umpa−H)${{{- \hfill \atop {\rm op}\hfill}}}$ species led to the formation of M2(Umpa−H)+ complexes that have one M2+ at the phosphonate and one at the (N3)− (plus carbonyl) site; this proves that nucleotides can bind metal ions independently at the phosphate and the nucleobase residues. X‐ray structural analyses of 6Umpa derivatives show that in diesters the phosphonate group is turned away from the uracil residue, whereas in H2(6Umpa) the orientation is such that upon deprotonation in aqueous solution a strong hydrogen bond is formed between (N1)H and PO32−; replacement of the hydro gen with M2+ gives the M(6Umpa−H)${{{- \hfill \atop {\rm cl}\hfill}}}$ chelates mentioned.
Three Polymorphic Forms of the Co‐Crystal 4,4′‐Bipyridine/Pimelic Acid and their Structural, Thermal, and Spectroscopic Characterization
Authors: Braga Dario , Palladino Giuseppe , Polito Marco , Rubini Katia , Grepioni Fabrizia , Chierotti Michele R. , Gobetto Roberto
Published: September 2008

Three crystal forms of the co‐crystal 4,4′‐bipy/pimelic acid (bipy: bipyridine), [NH4C5‐C5H4N]⋅[HOOC(CH2)5COOH], have been prepared and their relationship investigated by single‐crystal X‐ray diffraction, variable‐temperature X‐ray powder diffraction, differential scanning calorimetry and solid‐state NMR spectroscopy. Both X‐ray and NMR spectroscopic results indicate that no proton transfer takes place, that is, the three crystal forms are true co‐crystals of neutral molecules. Forms I and II both convert into Form III at high temperature, Forms II and III being the thermodynamically stable forms at room and high temperature, respectively.
New Templating Strategies with Salen Scaffolds (Salen=N,N′‐Bis(salicylidene)ethylenediamine Dianion)
Authors: Kleij Arjan W.
Published: September 2008

Templated approaches towards selective organic synthesis is a common feature in nature in which nucleic acid templated synthesis plays a crucial role in various fundamental biological processes. The key feature that allows control over the amazing selectivity found in natural processes is evidently the effective molarity of the reaction partners that is mediated by the macromolecular templation event. An ongoing challenge within many chemical sciences is to exploit similar templating principles and make use of synthetic systems that are designed for specific chemical conversions. Here, we describe the recent developments that involve (metallo)salen scaffolds that are used for diverse templating events (salen=N,N′‐bis(salicylidene)ethylenediamine dianion).
A mediation overview: History and dimensions of practice
Authors: Folberg Jay
Published: September 2008

What issues are facing today's mediators?
Divorce mediation: The state of the art
Authors: Milne Ann L.
Published: September 2008

Divorce mediation as practiced around the country is presented in this overview of practitioners, models, and methods of operation.
Mediation and psychotherapy: Distinguishing the differences
Authors: Kelly Joan B.
Published: September 2008

What expertise does the mediator need beyond that of the psychotherapist?
Mediation: Professional dynamics
Authors: Rosanova Michael Joseph
Published: September 2008

Can the welfare of clients be considered apart from the interests of organized professionals?
Strategies in child custody mediation: A family systems approach
Authors: Saposnek Donald T.
Published: September 2008

Use of perspectives and techniques grounded in family systems theory and brief strategic therapy adds to the mediator's effectiveness in mediating child custody disputes.
Emotional needs and dysfunctional communication as blocks to mediation
Authors: Barsky Morna
Published: September 2008

What techniques aid couples to communicate effectively during mediation?
Mediation in labor disputes and divorces: A comparative analysis
Authors: Markowitz James R. , Engram Pamela S.
Published: September 2008

What techniques proven effective in the resolution of labor conflicts are useful for the divorce mediator?
Mediation: An old art revitalized
Authors: Blades Joan
Published: September 2008

What are the differences between the models of mediation that have emerged?
The use of mediation by police
Authors: Palenski Joseph E.
Published: September 2008

How can police be encouraged to use mediation techniques and to refer family and community conflicts to mediation programs?
Arbitration and mediation in a neighborhood small claims project
Authors: Strena Robert V. , Westermark George D.
Published: September 2008

What is the impact of mediator style and availability of arbitration on the success of mediation?
A state–level approach to community arbitration and mediation
Authors: Gillie Michael S.
Published: September 2008

What is the typical range of arbitration and mediation services available?
Developing and funding community dispute settlement programs
Authors: Richan Anne
Published: September 2008

How can community mediation services start with minimum funding?
Error resilient data transport in sensor network applications: A generic perspective
Authors: Agarwal Rachit , Popovici Emanuel , Sala Massimiliano , O'Flynn Brendan
Published: September 2008

The error recovery problem in wireless sensor networks is studied from a generic resource‐constrained energy‐optimization perspective. To characterize the features of error recovery schemes that suit the majority of applications, an energy model is developed and inferences are drawn based on a suitable performance metric. For applications that require error control coding, an efficient scheme is proposed based on an interesting observation related to shortened Reed–Solomon (RS) codes for packet reliability. It is shown that multiple instances (γ) of RS codes defined on a smaller alphabet combined with interleaving results in smaller resource usage, while the performance exceeds the benefits of a shortened RS code defined over a larger alphabet. In particular, the proposed scheme can have an error correction capability of up to γ times larger than that of the conventional RS scheme without changing the rate of the code with much lower power, timing and memory requirements. Implementation results show that such a scheme is 43% more power efficient compared with the RS scheme with the same code rate. Besides, such an approach results in 46% faster computations and 53% reduction in memory requirements. Copyright © 2008 John Wiley & Sons, Ltd.
A new telomerase inhibitor and apoptosis‐inducing agent in leukemia: perylene derivative G‐quadruplex ligand Tel03
Authors: Chu Bin , Yuan Gu , Zhou Jiang , Ou Yuan , Zhu Ping
Published: September 2008

Tel03 (N,N′‐Bis‐(2‐(dimethylamino)ethyl)‐3,4,9,10‐perylentetra‐carboxylic acid diimide), a perylene derivative, was synthesized and its interaction with different forms of human telomeric DNA examined . The effect of Tel03 on leukemia cells in short‐term cultures was also used to explore its molecular actions. Electrospray ionization mass spectrometry (ESI‐MS) analysis indicated that Tel03 specifically recognizes telomeric quadruplex, not duplex DNA. After the treatment with Tel03 (0.1–10 µM) for 48 h, telomerase activity in K562 leukemia cell extracts was inhibited in a dose‐dependent manner as assessed with a telomere repeat amplification protocol (TRAP) assay. MTT assay results showed that Tel03 (0.1–10 µM) inhibited the proliferation of K562 cells after treatment for 72 h. In addition, apoptosis was observed. Using real‐time quantitative PCR and Western blot analysis, the expression of c‐myc and bcl‐2 was markedly down‐regulated at both the mRNA and protein levels. However, no changes were observed in the expression of bax. We conclude that G‐quadruplex ligand, Tel03, is a novel telomerase inhibitor and apoptosis‐inducing agent in leukemia cells acting via down‐regulation of bcl‐2 and c‐myc. Tel03 has the potential to be developed as an antileukemia drug. Drug Dev Res 69:235–241, 2008. © 2008 Wiley‐Liss, Inc.
Behavioral and biochemical effects of Kaixin‐San, a traditional Chinese medicinal empirical formula
Authors: Hu Yuan , Liu Ping , Dai‐Hong Guo , Rahman Khalid , Wang Dong‐Xiao , Chen Meng‐Li , Xie Ting‐Ting
Published: September 2008

Kaixin‐San (KXS), a traditional Chinese medicine, has been used in the treatment of depression. The present study was undertaken to investigate the effects of an ethanolic extract of KXS (KXS‐E) in mouse models of depression, the forced swim test (FST) and tail suspension test (TST). At doses of 500 mg/kg, KXS‐E reduced the immobility time in the FST and TST in mice 30 min after treatment. The main monoamine neurotransmitters and their metabolites in mouse brain regions were also simultaneously determined by HPLC‐ECD. KXS‐E not only increased the concentrations of 5‐HT and NE in whole brain, but also reduced the ratio of 5‐HIAA/5‐HT, slowing down 5‐HT metabolism as compared with mice treated with vehicle+stress. In conclusion, KXS‐E produced antidepressant‐like effects in a mouse model with a mechanism of action that may involve increased 5‐HT and NE in the mouse brain. Drug Dev Res 69:267–271, 2008. © 2008 Wiley‐Liss, Inc.
Variability of body weight, pulse pressure and glycaemia strongly predict total mortality in elderly type 2 diabetic patients. The Verona Diabetes Study
Authors: Zoppini Giacomo , Verlato Giuseppe , Targher Giovanni , Bonora Enzo , Trombetta Maddalena , Muggeo Michele
Published: September 2008

Background

Ageing is characterized by a decreased functional reserve, a concept defined as homeostenosis. We assessed the impact of long‐term exposure to the average value (mean) or to the variability (coefficient of variation) of fasting glycaemia, body mass index (BMI) and pulse pressure on total mortality in a cohort of type 2 diabetic patients.

Methods

Fasting glycaemia, BMI and pulse pressure values were collected over a period of 3 years in 1 319 type 2 diabetic patients who were subsequently followed up for 10 years. For each patient, the means and the coefficients of variation of fasting glycaemia, BMI and pulse pressure were computed. The adverse impact of these risk factors on total mortality was assessed in patients aged < 65 years (n = 565) and in those aged ≥ 65 years (n = 754), separately.

Results

During the 10 years of follow‐up, 438 patients died. In younger diabetic patients, the means of fasting glycaemia [hazard ratio (HR) of III tertile versus I tertile = 2.11, 95% confidence interval (CI): 1.22–3.64], BMI (HR = 1.88, 1.12–3.14) and pulse pressure (HR = 2.36, 1.34–4.16) were independently associated with total mortality, while in older patients they were not. In contrast, the coefficients of variation of glycaemia (HR = 1.56, 1.17–2.08), BMI (HR = 1.34, 1.03–1.75) and pulse pressure (HR = 1.34, 1.03–1.74) independently predicted total mortality only in older patients.

Conclusions

Our findings suggest that the variability of fasting glycaemia, body weight and blood pressure (BP) is independently associated with an increased risk of all‐cause mortality in older type 2 diabetic patients. Future studies are required to confirm the reproducibility of our findings. Copyright © 2008 John Wiley & Sons, Ltd.
Pitx2 deletion in pituitary gonadotropes is compatible with gonadal development, puberty, and fertility
Authors: Charles Michael A. , Mortensen Amanda H. , Potok Mary Anne , Camper Sally A.
Published: September 2008

This report introduces a gonadotrope‐specific cre transgenic mouse capable of ablating floxed genes in mature pituitary gonadotropes. Initial analysis of this transgenic line, Tg(Lhb‐cre)1Sac, reveals that expression is limited to the pituitary cells that produce luteinizing hormone beta, beginning appropriately at e17.5. Cre activity is detectable by a reporter gene in nearly every LHβ‐producing cell, but the remaining hormone‐producing cell types and other organs exhibit little to no activity. We used the Tg(Lhb‐cre)1Sac strain to assess the role Pitx2 in gonadotrope function. The gonadotrope‐specific Pitx2 knockout mice exhibit normal expression of LHβ, sexual maturation, and fertility, suggesting that Pitx2 is not required for gonadotrope maintenance or for regulated production of gonadotropins. genesis 46:507–514, 2008. © 2008 Wiley‐Liss, Inc.
Evolutionary conservation of vertebrate notochord genes in the ascidian Ciona intestinalis
Authors: Kugler Jamie E. , Passamaneck Yale J. , Feldman Taya G. , Beh Jeni , Regnier Todd W. , Di Gregorio Anna
Published: September 2008

To reconstruct a minimum complement of notochord genes evolutionarily conserved across chordates, we scanned the Ciona intestinalis genome using the sequences of 182 genes reported to be expressed in the notochord of different vertebrates and identified 139 candidate notochord genes. For 66 of these Ciona genes expression data were already available, hence we analyzed the expression of the remaining 73 genes and found notochord expression for 20. The predicted products of the newly identified notochord genes range from the transcription factors Ci‐XBPa and Ci‐miER1 to extracellular matrix proteins. We examined the expression of the newly identified notochord genes in embryos ectopically expressing Ciona Brachyury (Ci‐Bra) and in embryos expressing a repressor form of this transcription factor in the notochord, and we found that while a subset of the genes examined are clearly responsive to Ci‐Bra, other genes are not affected by alterations in its levels. We provide a first description of notochord genes that are not evidently influenced by the ectopic expression of Ci‐Bra and we propose alternative regulatory mechanisms that might control their transcription. genesis 46:697–710, 2008. © 2008 Wiley‐Liss, Inc.
Novel caspase‐suicide proteins for tamoxifen‐inducible apoptosis
Authors: Chu Yuanyuan , Senghaas Niklas , Köster Reinhard W. , Wurst Wolfgang , Kühn Ralf
Published: September 2008

Taking advantage of a mutant estrogen receptor ligand binding domain (ERT2), we developed novel Caspase fusion proteins for inducible apoptosis. We show that Caspase‐ERT2 fusion proteins become specifically activated by the synthetic ligand 4‐OH‐ tamoxifen and rapidly induce apoptotic cell death in human, murine, and zebrafish cells. This novel tool for targeted cell ablation greatly facilitates the generation of disease models as well as developmental and regeneration studies in model organisms. genesis 46:530–536, 2008. © 2008 Wiley‐Liss, Inc.
Generation and characterization of EphA1 receptor tyrosine kinase reporter knockout mice
Authors: Duffy Shannon L. , Coulthard Mark G. , Spanevello Mark D. , Herath Nirmitha I. , Yeadon Trina M. , McCarron Jennifer K. , Carter Jacinta C. , Tonks Ian D. , Kay Graham F. , Phillips Gael E. , Boyd Andrew W.
Published: September 2008

Eph receptor tyrosine kinases (RTKs) are a highly conserved family of signaling proteins with functions in cellular migration, adhesion, apoptosis, and proliferation during both adult and embryonic life. Here, we describe a knock‐in mouse in which EphA1 expression is disrupted via the insertion of an internal ribosome entry site (IRES)‐human placental alkaline phosphatase (ALPP) reporter cassette into exon II of the EphA1 gene. This was shown to successfully knockout expression of endogenous EphA1 and enforce expression of the ALPP reporter by the EphA1 promoter. Staining for the ALPP reporter protein demonstrated an epithelially restricted expression pattern in mouse tissues. In EphA1 null mice, two separate phenotypes were identified: abnormal tail development manifesting as a kinky tail was found in ∼80% of homozygous adults. A second, distinct abnormality present in ∼18% of females was characterized by imperforate uterovaginal development with hydrometrocolpos and caused by a resistance of cells to apoptosis during reproductive tract canalization. These results indicate a possible role for EphA1 in tissue patterning and hormone‐induced apoptotic processes. genesis 46:553–561, 2008. © 2008 Wiley‐Liss, Inc.
Design of new solid catalysts for the selective conversion of glycerol
Authors: Barrault Joel , Jerome François
Published: September 2008

Glycerol is now obtained as a co‐product of biodiesel from renewable raw materials with a dramatically increasing production. It follows that one of the most important breakthroughs is to find new catalytic processes for chemical valorizations. The present paper gives a short overview of selective esterification, transesterification or etherification of glycerol via the use of new heterogeneous catalysts. The selectivity control is mainly the result of the synthesis of mesoporous materials for which acidic or basic properties as well as the surface hydrophilic‐lipophilic balance were optimized.
Measurement of Nitrogen Mustard Degradation Products by Poly(dimethylsiloxane) Microchip Electrophoresis with Contactless Conductivity Detection
Authors: Ding Yongsheng , Rogers Kim
Published: September 2008

A poly(dimethylsiloxane) (PDMS) microfluidic device with contactless conductivity detection for the determination of nitrogen mustard degradation products is reported. Three alkyl ethanolamines: N‐methyldiethanolamine (MDEA), N‐ethyldiethanolamine (EDEA), and triethanolamine (TEA), (degradation/ precursor products of HN‐1, HN‐2 and HN‐3 blister agents) were analyzed by microchip capillary electrophoresis (CE). The original PDMS channel was coated by poly(ethyleneimine) (PEI) to improve the separation of three ethanolamines. Experimental conditions for the separation and detection processes have been optimized to yield well defined separation and high sensitivity. The response times for the three ethanolamines were less than 5 min., the detection limits were 2.0–4.0 mg L−1 and the relative standard derivations for the migration times and peak heights were 1.6–2.3% and 4.1–5.7%, respectively. The linearity of calibration for each of the compounds was as follows: MDEA, r2=0.970; EDEA, r2=0.994; TEA, r2=0.988. Applicability of this method for natural (lake and tap) water samples was also demonstrated. Compared to conventional analytical methods, this miniaturized system offers promise for on‐site monitoring of degradation products of the nitrogen mustard class of chemical warfare agents, with advantages of cost‐effective construction, simple operation, portability, and small required sample volumes.
Selective Electrochemical Epinephrine Sensor Using Self‐Assembled Monomolecular Film of 1,8,15,22‐Tetraaminophthalocyanatonickel(II) on Gold Electrode
Authors: Sivanesan Arumugam , John Swamidoss Abraham
Published: September 2008

This article describes the highly sensitive and selective determination of epinephrine (EP) using self‐assembled monomolecular film (SAMF) of 1,8,15,22‐tetraamino‐phthalocyanatonickel(II) (4α‐NiIITAPc) on Au electrode. The 4α‐NiIITAPc SAMF modified electrode was prepared by spontaneous adsorption of 4α‐NiIITAPc from dimethylformamide solution. The modified electrode oxidizes EP at less over potential with enhanced current response in contrast to the bare Au electrode. The standard heterogeneous rate constant (k°) for the oxidation of EP at 4α‐NiIITAPc SAMF modified electrode was found to be 1.94×10−2 cm s−1 which was much higher than that at the bare Au electrode. Further, it was found that 4α‐NiIITAPc SAMF modified electrode separates the voltammetric signals of ascorbic acid (AA) and EP with a peak separation of 250 mV. Using amperometric method the lowest detection limit of 50 nM of EP was achieved at SAMF modified electrode. Simultaneous amperometric determination of AA and EP was also achieved at the SAMF modified electrode. Common physiological interferents such as uric acid, glucose, urea and NaCl do not interfere within the potential window of EP oxidation. The present 4α‐NiIITAPc SAMF modified electrode was also successfully applied to determine the concentration of EP in commercially available injection.