bluuebunny/crossref_metadata_2025_split huggingface dataset:
Water‐elutability of nucleic acids from metal‐chelate affinity adsorbents: enhancement by control of surface charge density
Authors: Fu Joseph Y. , Potty Ajish S. R. , Fox George E. , Willson Richard C. 
Published: July 2006

AbstractImmobilized metal affinity chromatography (IMAC) is widely used for purification of proteins, especially “hexahistidine‐tagged” recombinant proteins. We previously demonstrated the application of IMAC to selective capture of nucleic acids, including RNA, selectively‐denatured genomic DNA, and PCR primers through interactions with purine bases exposed in single‐stranded regions. We also found that the binding affinity of nucleic acids for IMAC adsorbents can be increased several‐fold by addition of 20 volume% of neutral additives such as ethanol or DMSO. In the present work, it is demonstrated that bound nucleic acids can be effectively eluted with water instead of the usual imidazole‐containing competitive eluants, when the surface density of negative charges is enhanced by operation at alkaline pH, or by deliberate metal‐underloading of the anionic chelating ligands. With enhanced negative surface charge density, nucleic acid adsorption can be made strongly dependent on the presence of adsorption‐promoting additives and/or repulsion‐shielding salts, and removal of these induces elution. Complete water‐elutability is demonstrated for baker's yeast RNA bound to 10% Cu(II)‐ underloaded IDA Chelating Sepharose in a binding buffer of 20 mM HEPES, 240 mM NaCl, pH 7. Water elutability will significantly enhance the utility of IMAC in nucleic acid separations. Copyright © 2006 John Wiley & Sons, Ltd.
Interaction of sugars, polysaccharides and cells with boronate‐containing copolymers: from solution to polymer brushes
Authors: Ivanov Alexander E. , Galaev Igor Yu. , Mattiasson Bo 
Published: July 2006

AbstractInteraction of mono‐ and disaccharides, polysaccharide particles and yeast cells with boronate‐containing copolymers (BCC) of N‐acryloyl‐m‐aminophenylboronic acid (NAAPBA) with N,N‐dimethylacrylamide (DMAA) or N‐isopropylacrylamide (NIPAM) was studied. The binding of saccharides to BCC of NIPAM resulted in a shift of its phase transition temperature (ΔTP), which provided a quantitative measure for the complex formation. Among the sugars typical of non‐reducing ends of glycoproteins the ΔTP decreased in the order: N‐acetylneuraminic acid > xylose ≈ galactose > mannose ≈ fucose ≫ N‐acetylglucosamine. Strong specific adsorption of the BCC on the cross‐linked agarose gel Sepharose CL‐6B (15–30 mg/ml gel at pH 9.2) was registered. The copolymers adsorption was due to boronate‐sugar interactions and decreased with pH. Multivalent interaction of the BCC with the agarose gel has been proven by liquid column chromatography exhibiting a weak reversible adsorption of NAAPBA and almost irreversible adsorption of DMAA‐NAAPBA copolymer from 0.1 M sodium phosphate buffer, pH 7.9. The two studied BCCs could be completely desorbed from the gel by 0.1 M fructose in aqueous buffered media with pH from 7.5 to 9.2. In turn, the agarose particles and yeast cells were found to adhere to siliceous supports end‐grafted with boronate‐BCC of N,N‐dimethylacrylamide at pH ≥7.5, due to the actions. Quantitative detachment of adhered particles or cells could be attained by addition of 20 mM or 100 mM fructose, respectively, in the pH range from 7.5 to 9.2. Affinity adhesion of micron‐size carbohydrate particles to boronate‐containing polymer brushes fixed on solid supports was considered as a model system suggesting a new approach to isolation and separation of living cells. Copyright © 2006 John Wiley & Sons, Ltd.
On local non‐compactness in recursive mathematics
Authors: Simonsen Jakob G. 
Published: July 2006

AbstractA metric space is said to be locally non‐compact if every neighborhood contains a sequence that is eventually bounded away from every element of the space, hence contains no accumulation point. We show within recursive mathematics that a nonvoid complete metric space is locally non‐compact iff it is without isolated points.The result has an interesting consequence in computable analysis: If a complete metric space has a computable witness that it is without isolated points, then every neighborhood contains a computable sequence that is eventually computably bounded away from every computable element of the space. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The model theory of m‐ordered differential fields
Authors: Rivière Cédric 
Published: July 2006

AbstractIn his Ph.D. thesis [7], L. van den Dries studied the model theory of fields (more precisely domains) with finitely many orderings and valuations where all open sets according to the topology defined by an order or a valuation is globally dense according with all other orderings and valuations. Van den Dries proved that the theory of these fields is companionable and that the theory of the companion is decidable (see also [8]).In this paper we study the case where the fields are expanded with finitely many orderings and an independent derivation. We show that the theory of these fields still admits a model companion in the language L$^D_{<, m}$ = {+, –, ·, D, <1, …, <m, 1, 0}. We denote this model companion by CODFm and give a geometric axiomatization of this theory which uses basic notions of algebraic geometry and some generalized open subsets which appear naturally in this context. This axiomatization allows to recover (just by putting m = 1) the one given in [4] for the theory CODF of closed ordered differential fields. Most of the technics we use here are already present in [2] and [4].Finally, we prove that it is possible to describe the completions of CODFm and to obtain quantifier elimination in a slightly enriched (infinite) language. This generalizes van den Dries' results in the “derivation free” case. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Synthesis of Alkyl‐Functionalized Hyperbranched Polymers and Their Use as Additives in Cationic Photopolymerization of Epoxy Resins
Authors: Di Gianni Anna , Sangermano Marco , Malucelli Giulio , Voit Brigitte 
Published: July 2006

AbstractSummary: An alkyl‐functionalized hyperbranched polymer, HBP(OH)–C16, was synthesized by partial modification with fatty acid of an aromatic‐aliphatic OH‐terminated hyperbranched polyester HBPOH. This product was used as additive in the cationic photopolymerization of an epoxy resin. The alkyl‐modified polyester takes part in the photopolymerization process thanks to the residual OH groups by means of chain‐transfer reactions. An increase of the epoxy conversion is observed by increasing the amount of the HBP additive in the photocurable resin with a modification of the bulk properties of the final ultraviolet‐cured films. The presence of HBP(OH)–C16 induces an increase in glass transition temperature, thermal stability, and solvent resistance. Moreover the surface properties of the films are modified achieving highly hydrophobic surfaces in the presence of even very low amounts of HBP(OH)–C16.Structure of HBP–C16.magnified imageStructure of HBP–C16.
Copolymerization of Ethylene and 10‐Undecen‐1‐ol using a Montmorillonite‐Intercalated Metallocene Catalyst: Synthesis of Polyethylene/Montmorillonite Nanocomposites with Enhanced Structural Stability
Authors: Huang Yingjuan , Yang Kefang , Dong Jin‐Yong 
Published: July 2006

AbstractSummary: Ethylene and 10‐undecen‐1‐ol have been successfully copolymerized by an organically modified montmorillonite (OMMT)‐intercalated metallocene catalyst, Et[Ind]2ZrCl2, activated by methylaluminoxane (MAO). The obtained hydroxy‐functionalized polyethylene (PE‐OH)/OMMT nanocomposites exhibit enhanced structural stability as compared with the neat PE‐based ones, with no significant collapse of the nanocomposite structure being detected by WAXD examination after high‐temperature processing. The simultaneous polyolefin functionalization provides an effective and convenient solution to stabilize the PE/MMT nanocomposite structure formed by in‐situ polymerization.
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An Extremely Narrow‐Band‐Gap Conjugated Polymer with Heterocyclic Backbone and its Use in Optoelectronic Devices
Authors: Xia Yangjun , Deng Xianyu , Wang Li , Li Xianzhen , Zhu Xuhui , Cao Yong 
Published: July 2006

AbstractSummary: A novel narrow‐band‐gap conjugated polymer with heterocyclic backbone, poly[4,7‐bis(4‐decanyl‐2‐thienyl)‐2′,1′,3′‐benzothiadiazole‐thiophene‐2,5‐] (PDDBT, Eg = 1.38 eV) was synthesized by a Stille coupling reaction. Prototype bulk heterojunction photovoltaic cells from PDDBT and [6,6]‐phenyl‐C61‐butyric acid methyl ester (PCBM) with a ITO/PEDOT:PSS/PDDBT:PCBM(1:3)/Ba/Al device architecture showed power conversion efficiencies up to 0.13% under AM1.5 solar simulator (100 mW · cm−2) with an open‐circuit voltage Voc of 0.65 V, a short‐circuit current density Jsc of 0.6 mA · cm−2, and a photocurrent response up to 880 nm. The electroluminescent device from PDDBT showed a near‐infrared light emission peak at around 830 nm with maximal external quantum efficiency of 0.08% and a turn‐on voltage at 3.5 V.Normalized PL and EL spectra of PDDBT and photosensitivity of PVCs based on PDDBT/PCBM (1:3) blend. The scheme shows the chemical structure of PDDBT.magnified imageNormalized PL and EL spectra of PDDBT and photosensitivity of PVCs based on PDDBT/PCBM (1:3) blend. The scheme shows the chemical structure of PDDBT.
Preparation of Functionalized Polysilsesquioxane and Polysilsesquioxane‐Metal Nanoparticle Composite Spheres
Authors: Kim Young Baek , Kim Young‐A. , Yoon Kyung‐Sup 
Published: July 2006

AbstractSummary: Network polysilsesquioxane spheres made solely of poly(vinylsilsesquioxane) (PVSQ) and poly(3‐mercaptopropylsilsesquioxane) (PMPSQ) were prepared from heterogeneous mixtures of triethylamine (TEA), water, and either vinyltrimethoxysilane (VTMS), or 3‐mercaptopropyltrimethoxysilane (MPTMS). The microscopic, macroscopic observations, and the relationship between the diameters of spheres and the amount of each ingredient in the reaction system, showed that spheres formed via a mechanism similar to emulsion polymerization and suspension polymerization, depending on the reaction conditions. Diameters of spheres could be controlled from tens of nanometers to a few micrometers by adjusting the amounts of TEA, water, and a surfactant. Heating aqueous solutions of metal ions with these spheres produced polysilsesquioxanes (PSQ)‐metal nanoparticle composite spheres. The spheres prepared in this study were characterized by scanning electron microscopy, transmission electron microscopy, solid state NMR spectroscopy, IR spectroscopy, elemental analysis, and differential thermal analysis. These spheres would be useful in recovering metals from their ionic solutions and probes after chemical modifications.An image of the spheres of poly(vinylsilsesquioxane)‐gold nanoparticle composite.magnified imageAn image of the spheres of poly(vinylsilsesquioxane)‐gold nanoparticle composite.
Generation of Hierarchical Topologies from Photocrosslinkable, Particle‐Stabilized Emulsions
Authors: Benkoski Jason J. , Hu Hua , Karim Alamgir 
Published: July 2006

AbstractSummary: We describe a way to obtain biomimetic, hierarchical surface morphologies. In order to mimic natural surfaces more accurately such as lotus leaves and gecko feet, we employ a strategy that bears many of the attractive characteristics of natural materials synthesis. The system in question consists of a photocurable monomer and water. To this quasi‐two‐component system we add polymer latex spheres. The monomer–water interface is then manipulated according to the well‐established science of complex fluids. Drawing from the rich phase behavior of particle‐stabilized emulsions, we demonstrate the creation of complex biomimetic morphologies over many length scales. The resulting structures are then solidified by crosslinking the monomer with UV light.Comparison of an AFM image of a PMMA colloidosome assembly with that of the textured surface of a superhydrophobic Hygoryza aristata leaf (inset).magnified imageComparison of an AFM image of a PMMA colloidosome assembly with that of the textured surface of a superhydrophobic Hygoryza aristata leaf (inset).
Preparation of Robust Poly(ε‐caprolactone) Hollow Spheres with Controlled Biodegradability
Authors: Shi Zengqian , Zhou Yongfeng , Yan Deyue 
Published: July 2006

AbstractSummary: This work reports a new type of poly(ε‐caprolactone) (PCL) robust hollow sphere with controllable biodegradability, produced by grafting PCL shells from the surface of silica sphere cores and removing the template cores. Bis(ε‐caprolactone‐4‐yl) (BCY) composed of two ε‐caprolactone molecules was used as the crosslinker, which not only greatly strengthened the PCL hollow spheres but also brought hardly any non‐biodegradable component into the system. Solubility experiments and biodegradation tests show that the crosslinked PCL hollow spheres were robust both in water and acetone, and were completely biodegradable with characteristics of controllable biodegradability according to the content of the BCY. The Rhodamine release test indicated that the release rate of encapsulated drugs in the PCL hollow spheres was controlled by diffusion and the biodegradability of the PCL molecules, and the latter mechanism will dominate when more enzymes are involved.Reaction scheme for synthesis of linear and crosslinked hollow poly(ε‐caprolactone) spheres.magnified imageReaction scheme for synthesis of linear and crosslinked hollow poly(ε‐caprolactone) spheres.
Association between ulcerative growth and hypoxia inducible factor‐1α polymorphisms in colorectal cancer patients
Authors: Fransén Karin , Fenech Matthew , Fredrikson Mats , Dabrosin Charlotta , Söderkvist Peter 
Published: July 2006

AbstractThe hypoxia inducible factor‐1α (HIF‐1α) has been found to be involved in several different physiological mechanisms, such as blood‐vessel formation, apoptosis, and erythropoiesis. HIF‐1α is hydroxylated at normoxia and rapidly degraded via the von Hippel–Lindau (VHL)/ubiquitin‐proteasome degradation system to prevent angiogenesis. In a previous study, the C1772T (P582S) and the G1790A (A588T) polymorphisms were identified in the human HIF‐1α gene, which was shown to have a higher transactivating capability in vitro compared to the wild type allele. However, the role for these polymorphisms in vivo is still unclear. In the present investigation, we have therefore studied the role of the two polymorphic variants in the development of colorectal cancer (CRC) with PCR/RFLP (restriction fragment length polymorphism), single strand conformation analysis (SSCA), and immunohistochemistry (IHC). A significant higher‐risk was identified between patients heterozygous for the C1772T polymorphism and the more severe ulcerative growth pattern compared to homozygous C1772C wild type tumors (RR = 5.2; 95% CI 1.26–21.6; P = 0.006). This was also verified on the allelic level (RR = 6.5; 95% CI 1.58–26.8; P = 0.001). In addition, patients carrying one or more polymorphic alleles in either the HIF‐1α C1772T or the G1790A polymorphisms display significant higher risk for the development of ulcerative CRCs (RR = 4.17; 95% CI = 1.33–13.08; P = 0.004). These results suggest that the HIF‐1α polymorpisms are an important factor for development of a subset of ulcerative intestinal tumors. Future screening of the polymorphic HIF‐1α allele may therefore be of importance in the selection of treatment strategies of CRC. © 2006 Wiley‐Liss, Inc.
Diversity of contactin mRNA in human brain tumors
Authors: Rome Claire , Loiseau Hugues , Arsaut Josette , Roullot Valérie , Couillaud Franck 
Published: July 2006

AbstractIn order to address the molecular signature of human glioma, we investigated the polymorphism of 5′UTR of the mRNA of Contactin, an adhesion molecule which plays a role in the invasive behavior of these tumors. Contactin mRNA is identified by RT‐PCR and a strategy based on rapid amplification of cDNA ends (RACE) reveals different 5′UTRs resulting from both an alternative use of two types of leader exons and a splicing mechanism within the 5′UTR. The spliced exon is an Alu‐containing element specific to the primate lineage, thus indicating a recent evolution of regulatory processes specific to the simian line that occurs on this gene. Each 5′UTR exhibits different transcription/translation efficiencies and contains features that allow translation to occur independently of the classic cap‐dependent mechanism. These data illustrate the complex regulation of Contactin expression in human brain tumors occurring at both transcriptional and translation levels. The different 5′UTRs are differentially expressed in diverse types of human tumors. Thus, the polymorphism occurring within the non‐coding part of the contactin mRNA reveals new opportunities to explore deregulation that occurs during the oncogenic process. © 2006 Wiley‐Liss, Inc.
The impact of oocyte maturation media on early bovine embryonic development
Authors: Russell D. Fischer , Baqir S. , Bordignon J. , Betts D.H. 
Published: July 2006

AbstractSuccessful production of high quality blastocysts in vitro depends on the use of a culture system that ensures the acquisition of developmental competence by the maturing oocyte. It is now clear that the in vitro maturation environment has a major influence on the oocyte's ability to acquire the potential to develop into blastocysts. In this work we examine the impact of oocyte culture media on the quality of blastocysts by comparing developmental rates, cell number and their allocation to embryonic cell lineages, apoptosis, and expression of developmentally important genes. Higher total cell count and ICM:TCN ratio, which are indicative of embryo viability, were observed in embryos derived from oocyte maturation in TCM‐199 supplemented with serum when compared to blastocysts derived from oocyte maturation in SOF BSA. Moreover, oocyte maturation in TCM‐199 supplemented with serum‐generated embryos of higher morphological quality and producing higher levels of Interferon Tau transcripts when compared to embryos derived from oocyte maturation in SOF BSA. In conclusion, the oocyte maturation regimen affected the morphological feature of blastocysts, including total cell count and allocation of cells to trophectoderm (TE) and inner cell mass (ICM) lineages and the expression profiles of genes involved in various embryo functions such as early embryonic growth, regulation of gene transcription, trophoblast differentiation and function, embryo‐maternal communication, and stress response. Our results show that the oocyte culture media have strong impact on the quality of embryos produced in vitro and emphasize the need for more in depth evaluation of oocyte maturation protocols. Mol. Reprod. Dev. © 2006 Wiley‐Liss, Inc.
Remodeling of extracellular matrix at ovulation of the bovine ovarian follicle
Authors: Irving‐Rodgers H.F. , Catanzariti K.D. , Aspden W.J. , D'Occhio M.J. , Rodgers R.J. 
Published: July 2006

AbstractUsing immunohistochemistry and RNA analyses we examined the fate of components of a newly identified matrix that develops between granulosa cells (focimatrix, abbreviated from focal intraepithelial matrix) and of the follicular basal lamina in ovulating bovine ovarian follicles. Pre‐ and postovulatory follicles were generated by treatment with estradiol (Day 1), progesterone (Days 1–10), and prostaglandin analogue (Day 9) with either no further treatment (Group 1, n = 6) and or with 25 mg porcine LH (Day 11, Group 2, n = 8 or Day 10, Group 3, n = 8) and ovariectomy on Day 12 (12–14 hr post LH in Group 2, 38–40.5 hr in Group 3). In the time frame examined no loss of follicular basal lamina laminin chains β2 and γ1 or nidogen 1 was observed. In the follicular basal lamina collagen type IV α1 and perlecan were present prior to ovulation; after ovulation collagen type IV α1 was discontinuously distributed and perlecan was absent. Versican in the theca interna adjacent to the follicular basal lamina in preovulatory follicles was not observed post ovulation, however, the granulosa cells then showed strong cytoplasmic staining for versican. Expression of versican isoforms V0, V1, and V3 was detected at all stages. Focimatrix was observed in preovulatory follicles. It contained collagen type IV α1, laminins β2 and γ1, nidogen 1 and perlecan and underwent changes in composition similar to that of the follicular basal lamina. In conclusion focimatrix and the follicular basal lamina are degraded at ovulation. Individual components are lost at different times. Mol. Reprod. Dev. © 2006 Wiley‐Liss, Inc.
Public policy management councils in Brazil: how far does institutionalised participation reach?
Authors: Barth J. 
Published: July 2006

AbstractDuring the past two decades, Brazil has experienced a wide range of new participatory management instruments. One of the most important are the so called public policy management councils, composed of governmental and non‐governmental members, which have been implemented mainly in social sectors in order to discuss and develop public policies as well as to decide on the allocation of public funds. The practice shows that several structural factors still limit the potential of such a form of institutionalised participation. The most innovative result is without doubt the contribution towards transforming political culture, a prerequisite for the success of the ongoing democratisation process in most of the Latin American countries. Copyright © 2006 John Wiley & Sons, Ltd.
A perspective on road sector restructuring in developing and transitional countries
Authors: Robinson Richard 
Published: July 2006

AbstractA model derived within the World Bank sought to characterise how road administrations had evolved over time from large public works organisations to lean network administrators, working at arms‐length from government and making extensive use of contracts. The paper shows how two other pieces of work in this area help to explain why the evolution tends to happen in the manner identified. The first study concluded that a hierarchy of factors had to be addressed if organisational reform is to be successful: external factors need to be addressed to ensure that the context for restructuring is appropriate before attempting managerial and then technical changes within an organisation. The second study identified that, to achieve organisational effectiveness and efficiency, there is a need to increase the ‘specificity’ of the organisation and to subject it to competition. These factors explain the evolutionary model, with the initial stages of evolution tending to increase the specificity of the organisation, with the later stages subjecting more activities to competition. The evolutionary model was developed by observing how the restructuring process had progressed in countries such as New Zealand and the United Kingdom. However, the experience of restructuring in Romania is also summarised, confirming that the model also applies to countries making the transition to a market economy. The impact of administrative decentralisation on road sector performance is considered, and the types of decentralisation are identified offering the most promise in terms of sector restructuring. The combination of the results from these pieces of work provide a simple framework for understanding transition and restructuring in the road sector that can be used as the basis for developing restructuring plans. The approach is entirely consistent with the principles of the New Public Management, and there appears to be no reason why it should not be applied in other sectors wishing to restructure. Copyright © 2006 John Wiley & Sons, Ltd.