bluuebunny/crossref_metadata_2025_split huggingface dataset:
Blends of polypropylene with solid silicone additive
Authors: Muñoz P. M. Patricia , Werlang Moisés M. , Nachtigall Sônia M. B. , S. M. Cardozo Nilo , Mauler Raquel S. 
Published: January 2007

AbstractBlends of polypropylene (PP) and silicone masterbatch (SMBPP)—a commercial formulation consisting of an ultrahigh molecular weigh polydimethylsiloxane (PDMS) dispersed in PP—were prepared by melt mixing in an internal mixer. Four binary blends with different SMBPP content and two ternary blends containing silane‐grafted polypropylenes (PP‐VTES) of different VTES content as compatibilizer were produced. The blends were analyzed by melting flow rate, rotational rheometry, scanning electron microscopy, and differential scanning calorimetry (DSC). In all blends, the SMBPP remained as dispersed phase in the continuous PP matrix. The addition of PP‐VTES reduced significantly the size of the SMBPP domains. Rheological and morphological data strongly indicate that the PP‐VTES acts only by lowering the interfacial tension of the system without generating strong interaction between SMBPP domains and the PP matrix. The dimensions of the SMBPP domains and the interfacial energy were observed to determine the characteristics of the pseudoplastic behavior of the blends in the melt state. For both binary and ternary blends, the SMBPP domains showed nucleating effect leading to an increase of the degree of crystallinity. However, the decrease in the interfacial energy and viscosity promoted by the addition of PP‐VTES to the system led to a more intense nucleating effect and to an increase of crystallization, melting temperatures, and melting enthalpy. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 226–233, 2007
Novel Poly(vinyl alcohol)‐tetraethoxysilane hybrid matrix membranes as oxygen barriers
Authors: Patil Mallikarjunagouda B. , Patil Sangamesh A. , Veerapur Ravindra S. , Aminabhavi Tejraj M. 
Published: January 2007

AbstractNovel type of membranes based on poly(vinyl alcohol) crosslinked with tetraethoxysilane have been prepared by solution casting and solvent‐evaporation method. The membranes thus formed were characterized by Fourier transform infrared spectroscopy (FTIR) to study the chemical interactions, X‐ray diffraction (XRD), and thermogravimetry (TGA) to investigate morphological and thermal properties. Membranes were prepared in two different thicknesses (30 and 55 μm) and used for measuring the oxygen permeability under varying feed pressures (maintaining the desired pressure differential across the membrane) in the range from 1 to 50 kg/cm2 pressure. Oxygen permeability of the membranes ranged from 0.0091 to 1.6165 Barrer for 30 μm and 0.0305 to 0.1409 Barrer for 55‐μm thick membranes by increasing the feed pressures on the feed side. Except at 50 kg/cm2 pressure, the observed oxygen permeability values are almost close to total permeability. Membranes of this study could be useful as oxygen barriers for applications in food packaging industries. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 273–278, 2007
Preparation of genipin‐fixed agarose hydrogel
Authors: Meena Ramavatar , Prasad Kamalesh , Siddhanta A. K. 
Published: January 2007

AbstractGenipin, a naturally occurring crosslinker, was employed to modify agarose in aqueous medium at pH ∼ 7 at ambient conditions. The physical and rheological properties were studied. The genipin‐fixed agarose hydrogel (0.8 wt % genipin with respect to the polysaccharide) having the maximum swelling capacity was obtained after 85‐h crosslinking reaction. The reaction mixture developed a dark blue color with the passage of time, indicating thereby the progress of the crosslinking reaction in presence of genipin. The maximum swelling of the genipin‐fixed agarose hydrogel in acidic medium at pH 1.2 was ∼ 48 g/g, whereas the parent polysaccharide agarose achieved equilibrium swelling state at 6 g/g. The genipin‐fixed agarose showed 30% weight loss in Ringer's solution, while the agarose polysaccharide exhibited ∼ 50% weight loss in the same medium, both after 60 days. The thermogravimetric analysis studies revealed enhanced thermal stability of the genipin‐fixed agarose hydrogel. In view of the enhanced stability and swelling capacity of the genipin‐fixed agarose compared to agarose, the value added polysaccharide may be useful in new applications as super absorbents and in biomedical applications. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 290–296, 2007
Micro‐ and Nanometer‐Scale Porous, Fibrous, and Sheet Architectures Constructed by Supramolecular Assemblies of Dipyrrolyldiketones
Authors: Maeda Hiromitsu , Kusunose Yukio , Terasaki Masahiro , Ito Yoshihiro , Fujimoto Chikoto , Fujii Rika , Nakanishi Takashi 
Published: January 2007

AbstractX‐ray analysis of some 1,3‐dipyrrolyl‐1,3‐propanediones synthesized from pyrroles and malonyl chloride derivatives revealed 1D supramolecular networks formed by NH⋅⋅⋅OC interactions in the solid state. Micro‐ and nanometer‐scale morphologies of porous, fibrous, and sheet structures were fabricated by hydrogen‐bonding interactions and determined by fine‐tuning the substituents and the solvents used. Of the unique polymorphs, ordered 2D lamellar sheet structures of the derivatives with long alkyl chains (C16H33, C14H29, and so on) were constructed by van der Waals hydrophobic effects between aliphatic chains as well as hydrogen bonding.
Mechanistic Analysis of Nucleophilic Substrates Oxidation by Functional Models of Vanadium‐Dependent Haloperoxidases: A Density Functional Theory Study (Eur. J. Inorg. Chem. 4/2007)
Authors: Schneider Curtis J. , Zampella Guiseppe , Greco Claudio , Pecoraro Vincent L. , De Gioia Luca 
Published: January 2007

AbstractThe cover picture shows four substrates (Cl–, Br–, I–, and dimethyl sulfide) that all pass through nearly identical transition states when oxidized by (hydroperoxido)(oxido)vanadium(V) 2,2′‐[(2‐hydroxyethyl)imino]diacetate [VO(OOH)Hheida]. The differences in the physical properties of the substrate are represented by the changes in the color scheme for each panel. Despite the different “colors”, certain features of the transition states are always maintained, such as: nearly linear substrate peroxo oxygen bond angles, nucleophilic attack of the substrate on the unprotonated peroxo oxygen atom, and nearly complete hydroperoxo oxygen bond. This work lays the foundation for the development of more effective and potentially stereoselective catalysts based on the biomimetic catalyst V(OOH)Hheida. Details of this computational study can be found in the article by V. L. Pecoraro, and L. De Gioia on p. 515 ff.
A Simple Synthesis of Furo[3′,4′:5,6]pyrido[2,3‐d]pyrimidine Derivatives through Multicomponent Reactions in Water
Authors: Tu Shu‐Jiang , Zhang Yan , Jiang Hong , Jiang Bo , Zhang Jun‐Yong , Jia Run‐Hong , Shi Feng 
Published: January 2007

AbstractA series of furo[3′,4′:5,6]pyrido[2,3‐d]pyrimidine and indeno[2′,1′:5,6]pyrido[2,3‐d]pyrimidine derivatives were synthesized by three‐component reactions involving an aldehyde, 2,6‐diaminopyrimidine‐4(3H)‐one, and either tetronic acid or indane‐1,3‐dione in water, under microwave irradiation and traditional heating conditions, without use of any catalyst. This protocol has the advantages of higher yields, lower cost, reduced environmental impact, and convenience of procedure. The synthesis of a class of important compounds in aqueous medium has been achieved. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Glycals in Organic Synthesis: A Systematic Strategy for the Preparation of Uncommon Piperidine 1,2‐Dideoxy‐L‐azasugars and 2‐Deoxy‐1,5‐anhydro‐L‐hexitols
Authors: Ciliberti Elena , Galvani Roberta , Gramazio Francesca , Haddas Samantha , Leonelli Francesca , Passacantilli Pietro , Piancatelli Giovanni 
Published: January 2007

AbstractA systematic synthetic strategy has been developed for producing uncommon piperidine 1,2‐dideoxy‐L‐azasugars. This method involves the formation of open intermediates such as 2, 7, and 10 easily by ring‐opening of D‐glycals with aqueous mercury(II) acetate/sodium borohydride. A concise sequence of regioselective amination and cyclization reactions then allowed us to prepare the cyclic compounds 5a and 5b, L enantiomers of naturally occurring fagomine congeners such as 3‐epi‐fagomine (II) and 3,4‐di‐epi‐fagomine (III), from D‐glucal and D‐galactal, respectively. The unnatural 3,4‐di‐epi‐6‐deoxyfagomine 9 was obtained from L‐rhamnal by the same reaction sequence. This straightforward chemistry has been shown to be useful for preparing glycosyl derivatives of 1,2‐dideoxy‐L‐azasugars starting from glycosyl glycals such as D‐lactal, D‐cellobial, D‐maltal, and D‐melibial, thus avoiding the usually lengthy glycosylation procedures. The flexibility of our protocol has been demonstrated by the easy conversion of the above‐described open intermediates into uncommon 2‐deoxy‐1,5‐anhydro‐L‐hexitols, never previously described. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Cover Picture: Organic Reactions in Microemulsions (Eur. J. Org. Chem. 5/2007)
Authors: Holmberg Krister 
Published: January 2007

AbstractThe cover picture shows how a lipophilic reactant, 4‐tert‐butylbenzyl bromide, meets a hydrophilic reactant, an iodide ion, at the oil‐water interface of a microemulsion. The interface is covered by a monolayer of nonionic and cationic surfactants. Details are presented in the Microreview by K. Holmberg on p. 731 ff. (Mr. Tomasz Witula is acknowledged for drawing the figure.)
An empirical analysis of the impact of choice on waiting times
Authors: Siciliani Luigi , Martin Steve 
Published: January 2007

AbstractPolicy‐makers often claim that enhancing patient choice induces more competition among hospitals and may therefore reduce waiting times. This paper tests this claim using 120 English NHS hospitals over the period 1999–2001. Several proxies for the degree of choice (or competition) are constructed including: (a) the number of hospitals within the catchment area of each hospital; (b) the number of hospitals in the catchment area of each hospital standardised by the population of the catchment area; (c) the inverse of the Herfindahl index (or ‘the number of effective competitors’). Several control variables are included: the availability of doctors, junior doctors, nurses, and other personnel; the availability of acute beds; the emergency admission rate; the day‐case rate; the average length of inpatient stay; an indicator of case‐mix; and mortality and re‐admission rates. We find that more choice is significantly associated with lower waiting times at the sample mean (five hospitals) although the quantitative effect is modest: an extra hospital in a catchment area will only reduce waiting by at most a few days (or 1–2% reduction in waiting). There is also some evidence that increases in choice can boost waiting times when the degree of choice is very high (i.e. more than 11 hospitals are included in the catchment area). Copyright © 2007 John Wiley & Sons, Ltd.
Start‐stop funding, its causes and consequences: a case study of the delivery exemptions policy in Ghana
Authors: Witter Sophie , Adjei Sam 
Published: January 2007

AbstractThis article looks at the issue of sustaining funding for a public programme through the case study of the delivery exemptions policy in Ghana. The Government of Ghana introduced the policy of exempting users from delivery fees in September 2003 in the four most deprived regions of the country, and in April 2005 it was extended to the remaining six regions in Ghana. The aim of the policy of free delivery care was to reduce financial barriers to using maternity services. Using materials from key informant interviews at national and local levels in 2005, the article examines how the policy has been implemented and what the main constraints have been, as perceived by different actors in the health system. The interviews show that despite being a high‐profile public policy and achieving positive results, the delivery exemptions policy quickly ran into implementation problems caused by inadequate funding. They suggest that facility and district managers bear the brunt of the damage that is caused when benefits that have been promised to the public cannot be delivered. There can be knock‐on effects on other public programmes too.Despite these problems, start‐stop funding and under‐funding of public programmes is more the norm than the exception. Some of the factors causing erratic funding—such as party politics and intersectoral haggling over resources—are unavoidable, but others, such as communication and management failures can and should be addressed. Copyright © 2007 John Wiley & Sons, Ltd.
Synthesis of 3H‐ and 2H4‐labelled versions of the hypoxia‐activated pre‐prodrug 2‐[(2‐bromoethyl)‐2,4‐dinitro‐6‐ [[[2‐(phosphonooxy)ethyl]amino]carbonyl]anilino]ethyl methanesulfonate (PR‐104)
Authors: Atwell Graham J. , Denny William A. 
Published: January 2007

Abstract3H‐ and 2H4‐versions of the hypoxia‐activated pre‐prodrug PR‐104 [2‐[(2‐bromoethyl)‐2,4‐dinitro‐6‐[[[2‐(phosphonooxy)ethyl]amino]carbonyl]anilino]ethyl methanesulfonate], labelled in the ethylcarboxamide side chain, have been prepared, respectively, by [3H]NaBH4 reduction of a precursor late stage aldehyde, and by late stage incorporation of deuterium with 2‐amino[1,1,2,2‐2H4]ethanol. Copyright © 2007 John Wiley & Sons, Ltd.
Preparation and biodistribution of novel 99mTc(CO)3‐CNR complexes for myocardial imaging
Authors: Hao Guiyang , Zang Jianying , Liu Boli 
Published: January 2007

AbstractWe evaluated lipophilicity and biodistribution of a series of 99mTc(CO)3‐ether isonitrile complexes to determine whether different lipophilicity and structure of isonitrile ligands would improve the imaging properties of the radiopharmaceutical for the heart. Novel 99mTc(CO)3‐MIBI analogs were prepared and analyzed by radio‐HPLC, and their lipophilicity was determined. These new complexes could be bi‐ or tri‐substituted in specified pH conditions like 99mTc(CO)3‐MIBI. These new complexes exhibited low liver, lungs and blood uptake compared with [99mTc(CO)3(MIBI)3]+ though their heart uptake was not so high. Among these complexes, [99mTc(CO)3(EPI)2(OH2)]+ showed higher target to non‐target ratios at 5 and 30 min post‐injection than that of [99mTc(CO)3(MIBI)3]+. Copyright © 2007 John Wiley & Sons, Ltd.
NMR spectra of the tautomeric mixture of two forms of 6‐azidopurine ribonucleoside labeled with 15N
Authors: Masternak Anna , Skalski Bogdan , Milecki Jan 
Published: January 2007

Abstract6‐Azidopurine nucleoside labeled with 15N at N‐1 position was synthesized. 15N NMR spectra, 15N‐1H and 15N‐13C coupling constants were measured. Two well‐separated sets of signals for two tautomeric forms were detected. Copyright © 2007 John Wiley & Sons, Ltd.
Preseizure increased gamma electroencephalographic activity has no effect on extracellular potassium or calcium
Authors: Broberg Marita , Pope Kenneth J. , Nilsson Michael , Wallace Angus , Wilson Jodie , Willoughby John O. 
Published: January 2007

AbstractExtracellular ion concentrations change during seizures in seizure models. [K+]o increases and [Ca2+]o decreases, resulting from population discharges, enhanced neuronal excitability, though not obviously before seizure onset. In acute pharmacological epilepsy models, there are striking increases in preictal high‐frequency (gamma) electroencephalographic (EEG) activity. It is not known whether enhanced gamma EEG results in ionic changes, because gamma and ions have not been measured simultaneously. In this study, unanesthetized, paralyzed rats were given intravenous injections of kainic acid or picrotoxin to induce EEG discharges. Changes in EEG, [K+]o, and [Ca2+]o in cortex and hippocampus were recorded. Kainic acid caused small [K+]o fluctuations, without a temporal relationship of these with increased gamma EEG or with onset of discharges. Gamma EEG increases after picrotoxin also failed to affect [K+]o and [Ca2+]o. Picrotoxin‐induced electrical discharges led to [K+]o rises of >9 mM and [Ca2+]o falls of 0.1–0.2 mM. Kainic acid‐induced discharges generated only moderate (2–3 mM) rises in [K+]o and no changes in [Ca2+]o. In both models, there were large potassium rises (15–80 mM) and calcium falls (>0.5 mM), suggesting spreading depressions. Small [K+]o fluctuations after kainic acid are consistent with disruption in potassium homeostasis, possibly because of depolarization of astrocytes. To reveal possible latent [K+]o or [Ca2+]o changes, we injected fluorocitrate intracortically to impair astrocytic function, before administering picrotoxin. Even fluorocitrate did not cause gamma‐related ion changes but did cause low‐magnitude, transient, potassium increases and slower potassium homeostasis during discharges, minor changes consistent with involvement of both astrocytes and neurons in [K+]o regulation. © 2007 Wiley‐Liss, Inc.
Downscaling of current and future rainfall climatologies for southern Morocco. Part II: Climate change signals
Authors: Huebener H. , Kerschgens M. 
Published: January 2007

AbstractClimate simulations from ECHAM4/OPYC3 (IS92a scenario) and ECHAM5/MPI‐OM1 (SRES A1B scenario) are analysed regarding their precipitation change signal in southern Morocco at the border of the Saharan desert. Results are obtained from statistical‐dynamical downscaling, using circulation weather types (CWTs) as driving fields. The trends obtained from the two climate models between their respective control (1969–1989) and scenario (2060–2089) periods are added to climatology obtained form NCEP reanalysis data (1958–1997). The resulting changes are compared to general circulation models (GCM) simulated rainfall changes.Application of the climate trends between the respective control and scenario periods of the two data sets to the climatology obtained from NCEP reanalyses leads to an increase of days with CWTs that favour rainfall in the region. This would lead to an enhanced rainfall amount by 20% for the ECHAM4/OPYC3 IS92a run and rainfall increase of 8% for the ECHAM5/MPI‐OM1 model A1B run. These findings are rather surprising, since the simulated rainfall developments from ECHAM5/MPI‐OM1 model A1B run gives a negative precipitation tendency for the area (ca − 25 mm/a) and the ECHAM4/OPYC3 IS92a run depicts a slight rise in rainfall rates (ca + 25 mm/a), due to enhanced moisture transport in a warmer atmosphere. Thermodynamic aspects are not considered here since the used approach is purely dynamical. The contradicting rainfall tendencies are attributed to the coarse resolution of the GCMs and the important role the High Atlas Mountain range plays in the mechanisms generating precipitation in the region. Copyright © 2007 Royal Meteorological Society
Progress in the methodological strategies for the detection in real samples of desmosine and isodesmosine, two biological markers of elastin degradation
Authors: Viglio Simona , Annovazzi Laura , Luisetti Maurizio , Stolk Jan , Casado Begoña , Iadarola Paolo 
Published: January 2007

AbstractDesmosines are crosslinking amino acids unique to mature elastin in humans. Owing to this unicity, they have been discussed as potentially attractive indicators of connective tissue disorders whose clinical manifestations are mostly the result of elastin degradation. This review covers advances in immunochemical, chromatographic, and electrophoretic procedures applied in the last 25 years to detect and quantitate these crosslinks in a variety of biological samples. Recent applications of CE with LIF detection (CE‐LIF) for investigating the content of desmosines in different fluids will also be discussed.
Nondigest liberation of biomarkers from plasma: A novel two‐stage ultrafiltration approach
Authors: Rogatsky Eduard , Tomuta Vlad , Stein Daniel T. 
Published: January 2007

AbstractA simple procedure for sample preparation of human plasma by two stages of ultrafiltration using one device is described. Our approach is useful for nondigest liberation of biomarkers bound to albumin and other plasma proteins. The analyte contained in the ultrafiltrate can be directly analyzed without additional sample preparation, and quantified by 2‐D RP–RP LC/MS.
Phenylethynyl End‐Capped Fluorinated Imide Oligomer AFR‐PEPA‐N: Morphology and Processibility Characteristics
Authors: Li Yuntao , Murphy Lindsay A. , Lincoln Jason E. , Morgan Roger J. 
Published: January 2007

AbstractTwo phenylethynyl phthalic anhydride‐capped imide oligomers, AFR‐PEPA‐2 and AFR‐PEPA‐8, with molecular weights of 1 601 and 4 699 g · mol−1, respectively, were synthesized and characterized. The AFR‐PEPA‐N oligomers show higher glass transition temperatures and higher thermal decomposition temperatures than phenylethynyl‐terminated imide PETI‐5. After curing for 1 h at 390 °C, AFR‐PEPA‐2 and AFR‐PEPA‐8 have Tgs of 370 and 358 °C, respectively. AFR‐PEPA‐N oligomers demonstrated lower minimum complex melt viscosities than PETI‐5 due to the presence of CF3 group in the backbone structure. 1 601 g · mol−1 AFR‐PEPA‐2 imide oligomer has a complex melt viscosity of 10 Pa · s at 340 °C, and 4 699 g · mol−1 AFR‐PEPA‐8 imide oligomer has a complex melt viscosity of 227 Pa · s at 371 °C. AFR‐PEPA‐N film's crystal morphology was observed using polarized optical microscopy and the AFR‐PEPA‐8 oligomer did not show crystallinity. AFR‐PEPA‐2 film exhibits semicrystalline behavior and the crystallinity does not disappear until the film is cured above 375 °C.magnified image
Influence of Low Fractions of Styrene/Butyl Acrylate Polymer Latexes on Some Properties of Ordinary Portland Cement Mortars
Authors: Boutti Salima , Urvoy Marie , Dubois‐Brugger Isabelle , Graillat Christian , Bourgeat‐Lami Elodie , Spitz Roger 
Published: January 2007

AbstractThe influence of the chemical structure of styrene/butyl acrylate latexes on some properties of ordinary Portland cement mortars has been investigated for low fractions of polymer with respect to the amount of cement. The structural parameters that were varied included the presence of carboxylic surface charges, the nature of the surfactant system, the molecular weight of the non‐ionic emulsifier, and the particle surface coverage. The first part of the study showed that sterically stabilised latexes remain colloidally and chemically stable for several hours in the cement interstitial medium. Moreover, no interaction could be shown between cement and latex components. Then, for a fraction of about 5wt.‐% of polymer, no significant influence of the presence of the latex was observed on the end‐use properties of the mortars. However, it clearly appears that the use of a fraction of anionic stabiliser is highly detrimental to the paste workability, whereas this latter property is improved by the presence of non‐ionic surfactant due to steric repulsion forces. Finally, the microstructure analysis confirms that the particles are homogenously dispersed in the mineral matrix and that they remain smooth and spherical.magnified image
The Effect of Functionalized Ethylene Propylene Diene Rubber (EPDM) on the Kinetics of Sulfur Vulcanization of Normal Rubber/EPDM Blends
Authors: Sirqueira Alex S. , Soares Bluma G. 
Published: January 2007

AbstractThe effect of mercapto‐ and anhydride‐functionalized ethylene propylene diene rubber (EPDM) or ethylene–vinyl acetate (EVA) copolymers on the vulcanization kinetics of natural rubber/EPDM blends was investigated using the oscillatory disk rheometer. The mercapto groups in both EPDM and EVA copolymers resulted in a significant decrease of the curing time. The Coran's model was applied to set the kinetic constants within each distinct step of the vulcanization process. The highest curing velocity was perceived in a blend containing 2.5 phr of mercapto‐functionalized EVA. The functionalized EVA, especially that which was functionalized with anhydride groups, also displayed a lower solvent uptake on blending, which would imply an increase of the crosslink density as well a covulcanization phenomenon.magnified image