bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tissue‐specific differences in 2‐fluoro‐2‐deoxyglucose metabolism beyond FDG‐6‐P: a 19F NMR spectroscopy study in the rat
Authors: Southworth Richard , Parry Craig R. , Parkes Harold G. , Medina Rodolfo A. , Garlick Pamela B. 
Published: December 2003

Abstract2‐Fluoro‐[18F]‐2‐deoxy‐glucose (FDG) is a positron‐emitting analogue of glucose used clinically in positron emission tomography (PET) to assess glucose utilization in diseased and healthy tissue. Originally developed to measure local cerebral glucose utilization rates, it has now found applications in tumour diagnosis and in the study of myocardial glucose uptake. Once taken up into the cell, FDG is phosphorylated to FDG‐6‐phosphate (FDG‐6‐P) by hexokinase and was originally believed to be trapped as a terminal metabolite. This ‘metabolic trapping’ of FDG‐6‐P forms the basis of the analysis of PET data. In this study, we have used 19F NMR spectroscopy to investigate FDG metabolism following the injection of a bolus of the glucose tracer into the rat (n=6). Ninety minutes after the 19FDG injection, the brain, heart, liver and kidneys were removed and the 19FDG metabolites in each were extracted and quantified. We report that significant metabolism of FDG occurs beyond FDG‐6‐P in all organs examined and that the extent of this metabolism varies from tissue to tissue (degree of metabolism beyond FDG‐6‐P, expressed as percentage of total organ FDG content, was brain 45 ± 3%; heart 29 ± 2%; liver 22±3% and kidney 17 ± 3%, mean ± SEM n=6). Furthermore, we demonstrate that the relative accumulation of each metabolite was tissue‐dependent and reflected the metabolic and regulatory characteristics of each organ. Such inter‐tissue differences may have implications for the mathematical modelling of glucose uptake and phosphorylation using FDG as a glucose tracer. Copyright © 2003 John Wiley & Sons, Ltd.
Proton T1 relaxation times of cerebral metabolites differ within and between regions of normal human brain
Authors: Brief E. E. , Whittall K. P. , Li D. K. B. , MacKay A. 
Published: December 2003

AbstractSaturation recovery spectra (STEAM) were acquired at 1.5 T with 7 TRs ranging from 530 to 5000 ms and a constant TE of 30 ms in voxels (7.2 ml) located in occipital grey, parietal white and frontal white matter (10 subjects each location). Spectra were also acquired at 7, 21 and 37°C from separate 100 mm solutions of inositol (Ins), choline‐containing compounds (Cho), N‐acetyl‐aspartate (NAA) and creatine. Simulations of T1 fits with 2, 3 and 7 TRs demonstrated that at typical SNR there is potential for both inaccurate and biased results. In vivo, different metabolites had significantly different T1s within the same brain volume. The same order from shortest to longest T1 (Ins, Cho, NAA, creatine) was found for all three brain regions. The order (Ins, NAA, creatine, Cho) was found in the metabolite solutions and was consistent with a simple model in which T1 is inversely proportional to molecular weight. For all individual metabolites, T1 increased from occipital grey to parietal white to frontal white matter. This study demonstrates that, in spectra acquired with TR near 1 s, T1 weightings are substantially different for metabolites within a single tissue and also for the same metabolites in different tissues. Copyright © 2003 John Wiley & Sons, Ltd.
Increased statin prescribing in patients with diabetes after the introduction of the NSF for Coronary Heart Disease
Authors: Bull N , Williams J , Nicholls P , Lawrenson RA 
Published: December 2003

AbstractCardiovascular disease accounts for 70% of deaths in people with diabetes. This is partly due to their abnormal lipoprotein profiles. Several studies have shown that the prescription of statins to this group of people can greatly reduce the risk of death. The National Service Framework for Coronary Heart Disease (NSF for CHD), introduced in March 2000, set targets for treating people at high risk of death from CHD. Our study looked at 14 practices in Surrey to see whether the NSF has had an impact on statin prescribing in people with diabetes over the age of 40. There has been a 21% increase in the prevalence of diabetes between 1999 and 2002. We have also shown a 74% increase in the prescribing of statins to people with diabetes following the introduction of the NSF for CHD. The increase in the number of people receiving statins has cost implications for primary care trusts. Copyright © 2003 John Wiley & Sons, Ltd.
‘I'm amazed I've been able to come off injections’: patients' perceptions of genetic testing in diabetes
Authors: Shepherd M 
Published: December 2003

AbstractMaturity onset diabetes of the young (MODY) accounts for 1% of diabetes in the UK but the young age of diagnosis, high glucose values in slim patients and lack of professionals' familiarity with the family history often lead to a misdiagnosis of type 1 diabetes. The identification of six different genes that cause MODY means that genetic testing may confirm the diagnosis and define the subtype. MODY patients with a mutation in the hepatocyte nuclear factor‐1 alpha (HNF‐1 alpha) gene are known to be particularly sensitive to the hypoglycaemic effect of sulphonylureas which has implications for their treatment. In depth interviews were conducted with 18 HNF‐1 alpha MODY patients, on insulin from diagnosis, who were offered the possibility of transferring to a sulphonylurea. A qualitative approach was used to gain an in depth understanding of their perceptions about stopping insulin. Six key themes emerged: (i) concern and anticipation about the prospect of stopping insulin; (ii) interactions with health care professionals; (iii) the impact on glycaemic control; (iv) improved lifestyle and self‐image; (v) reflections regarding the time on insulin; and (vi) difficulty in ‘letting go’ of insulin treatment. Transferring insulin treated HNF‐1 alpha MODY patients to sulphonylureas was safe in the short term. All 18 patients reported positive lifestyle changes and most showed no deterioration in glycaemic control, although the progressive nature of HNF‐1 alpha MODY means they are likely to need insulin again in the future. These findings have implications for other patients able to stop insulin after many years, such as those undergoing islet cell transplantation. Copyright © 2003 John Wiley & Sons, Ltd.
Preparation of macromonomers by copolymerization of methyl acrylate dimer involving β fragmentation
Authors: Harada Takahiro , Zetterlund Per B. , Yamada Bunichiro 
Published: December 2003

AbstractThe unsaturated dimer of methyl acrylate [CH2C(CO2CH3)CH2CH2CO2CH3, or MAD] was copolymerized with various monomers to prepare copolymers bearing the ω‐unsaturated end group [CH2C(CO2CH3)CH2] arising from β fragmentation of the MAD propagating radical. Copolymerizations of MAD with cyclohexyl and n‐butyl acrylate resulted in copolymers with ω‐unsaturated end groups, and increasing the temperature up to 180 °C resulted in an increase in the rate of β fragmentation of MAD radicals relative to propagation. Only a small amount of unsaturated end groups was introduced by copolymerization with ethyl methacrylate (EMA), and the EMA content in the copolymer increased with temperature. These findings could be explained by the reversible addition of the poly(EMA) radical to MAD. The copolymerization with ethyl α‐ethyl acrylate (EEA) did yield a copolymer containing unsaturated end groups with MAD units as part of the main chain, although the steric hindrance of the ethyl group suppressed homopropagation and crosspropagation of EEA, resulting in low polymerization rates. Therefore, the copolymerization of MAD with acrylic esters at high temperatures was noted as a convenient route for obtaining acrylate–MAD copolymers bearing unsaturated end groups at the ω end (macromonomer). © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 597–607, 2004
New functionalized polyesters to achieve controlled architectures
Authors: Finne Anna , Albertsson Ann‐Christine 
Published: December 2003

AbstractFollowing our continued interest in the production of bioerodible and biodegradable functional polymers for biomedical applications, we synthesized and characterized new unsaturated polyesters. The presence of functional groups in the polymer backbone provided sites for chemical modification, and through a variation in the structure, the physical properties, such as the hydrophilicity and solubility, could be affected. With 1,1‐di‐n‐butyl‐stanna‐2,7‐dioxacyclo‐4‐heptene as the initiator in the ring‐opening polymerization of polyesters, a new set of functionalized polyesters was created. The polymerization of ϵ‐caprolactone resulted in poly(ϵ‐caprolactone) with a double bond incorporated into the structure. The polymers were obtained in a controlled manner with low molecular dispersities. The double bond was previously incorporated into L‐lactide polymers, and the two reactions were compared in this study. The conversion of ϵ‐caprolactone, with a degree of polymerization of 50, was completed within 140 min, whereas for L‐lactide, only a 45% conversion took place in the same period of time. The dispersities were somewhat higher with ϵ‐caprolactone because of the higher reaction rate and, therefore, lower selectivity. The incorporated CC double bond in the polyesters provided a variety of opportunities for further modifications. In this case, the double bond of the L‐lactide macromonomers was oxidized into epoxides. Epoxidation was carried out with m‐chloroperoxybenzoic acid as a chemical reagent. The conversion of the double bonds into epoxides was completed, and the obtained yields were good (>95%). As a result of the mild reaction conditions, the epoxidation of the double bond was carried out quantitatively without any side reactions. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 444–452, 2004
Biofunctional rapid prototyping for tissue‐engineering applications: 3D bioplotting versus 3D printing
Authors: Pfister Andreas , Landers Rüdiger , Laib Andres , Hübner Ute , Schmelzeisen Rainer , Mülhaupt Rolf 
Published: December 2003

AbstractTwo important rapid‐prototyping technologies (3D Printing and 3D Bioplotting) were compared with respect to the computer‐aided design and free‐form fabrication of biodegradable polyurethane scaffolds meeting the demands of tissue‐engineering applications. Aliphatic polyurethanes were based on lysine ethyl ester diisocyanate and isophorone diisocyanate. Layer‐by‐layer construction of the scaffolds was performed by 3D Printing, that is, bonding together starch particles followed by infiltration and partial crosslinking of starch with lysine ethyl ester diisocyanate. Alternatively, the 3D Bioplotting process permitted three‐dimensional dispensing and reactive processing of oligoetherurethanes derived from isophorone diisocyanate, oligoethylene oxide, and glycerol. The scaffolds were characterized with X‐ray microtomography, scanning electron microscopy, and mechanical testing. Osteoblast‐like cells were seeded on such scaffolds to demonstrate their potential in tissue engineering. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 624–638, 2004
Role of minority structures and mechanism of peroxide crosslinking of polyethylene
Authors: Lazár Milan , Kleinová Angela , Fiedlerová Agnesa , Janigová Ivica , Borsig Eberhard 
Published: December 2003

AbstractMinority structures are considered to be defect structures that are formed during polyethylene (PE) preparation and during the crosslinking process in PE. The minority structures that play the predominant role in PE crosslinking are vinyl double bonds. Moreover, the decomposition of dicumyl peroxide in PE does not proceed according to first‐order kinetics, but induced peroxide decomposition also takes part. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 675–688, 2004
Biopolymers for biocatalysis: Structure and catalytic mechanism of hydroxynitrile lyases
Authors: Gruber Karl , Kratky Christoph 
Published: December 2003

AbstractHydroxynitrile lyases catalyze the reversible cleavage of α‐cyanohydrins to yield hydrocyanic acid and the corresponding aldehyde or ketone. Besides its biological interest, this class of enzymes is also of relevance in industrial biocatalysis for the enantioselective condensation of HCN with a variety of aldehydes and ketones. Several distinctly different types of hydroxynitrile lyases (HNLs) are known, which must have originated through convergent evolution from different ancestral proteins. Three‐dimensional structural data are known for three classes of hydroxynitrile lyases. Insights into the reaction mechanisms emerged from a combination of structural, enzyme kinetic, spectroscopic, and molecular modeling data. For all three types of HNLs, mechanisms involving acid–base catalysis were proposed. In members belonging to the α,β‐hydrolase type, the amino acid residues of the catalytic triad presumably act as general acid/base, whereas for flavine adenine dinucleotide (FAD)‐dependent HNLs a single histidine residue fulfills this function. In the third type of HNL—which is related to carboxypeptidase—acid–base catalysis involves the carboxylate of the C‐terminal residue. The catalytic relevance of a positive electrostatic potential in the active site was suggested in some of the mechanistic proposals. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 479–486, 2004
Thermal oxidation of nonstabilized and stabilized polymers and chemiluminescence
Authors: Matisová‐Rychlá L. , Rychlý J. 
Published: December 2003

AbstractThe chemiluminescence under isothermal and nonisothermal conditions accompanying the oxidation of some polymers (polyolefins, polyamides, and polysaccharides) has been examined from the viewpoint of its relationship with the rate of oxidation. The chemical structure of a given type of polymer plays a decisive role in the resulting shape of the chemiluminescence curves. In the presence of an antioxidant, the inhibition periods of oxidation are shifted to longer times and/or higher temperatures. This shift is directly proportional to the type and concentration of stabilizer. Attention has also been paid to the impact of the average molar mass on the oxidizability of the macromolecular material. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 648–660, 2004
Matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry analysis of atom transfer radical polymerization macroinitiators derived from poly(3‐ethyl‐3‐hydroxymethyloxetane)
Authors: Bednarek Melania , Kubisa Przemysław 
Published: December 2003

AbstractThe matrix‐assisted laser desorption/ionization time‐of‐flight analysis of macroinitiators for atom transfer radical polymerization prepared by the functionalization of a multihydroxyl, highly branched polyether, poly(3‐ethyl‐3‐hydroxymethyloxetane), allows the exact determination of the macroinitiator functionality, providing information on the number of bromine atoms in individual macromolecules, in contrast to NMR analysis, which gives average values. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 608–614, 2004
Thermosensitive sol–gel transition behaviors of poly(ethylene oxide)/aliphatic polyester/poly(ethylene oxide) aqueous solutions
Authors: Song M. J. , Lee D. S. , Ahn J. H. , Kim D. J. , Kim S. C. 
Published: December 2003

AbstractThe thermoreversible gelation of Pluronic [poly(ethylene oxide) (PEO)–polypropylene oxide (PPO)–PEO] aqueous solutions originates from micelle formation and micelle volume changes due to PEO–water and PPO–water lower critical solution temperature behavior. The micelle volume fraction is known to dominate the sol–gel transition behavior of Pluronic aqueous solutions. Triblock copolymers of PEO and aliphatic polyesters, instead of PPO, were prepared by hexamethylene diisocyanate coupling and dicyclohexyl carbodiimide coupling. Through changes in the molecular weight and hydrophobicity of the polyester middle block, the hydrophobic–hydrophilic balance of each block was systematically controlled. The following aliphatic polyesters were used: poly(hexamethylene adipate) (PHA), poly(ethylene adipate) (PEA), and poly(ethylene succinate) (PESc). With the hydrophobicity and molecular weight of the middle block increasing, the critical micelle concentration at the same critical micelle temperature decreased, and the absolute value of the micellization free energy increased. The micelle size was rather insensitive to temperature but slightly decreased with increasing temperature. PEO–PHA–PEO and PEO–PEA–PEO triblock copolymers needed high polymer concentrations to form gels. This was ascribed to the tight aggregation of PHA and PEA chains in the micelle core due to strong hydrophobic interactions, which induced the contraction of the micelle core. However, because of the relatively hydrophilic core, a PEO–PESc–PEO aqueous solution showed gelation at a low polymer concentration. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 772–784, 2004
Hydrogen‐bonded supramolecular poly(ether ketone)s
Authors: Kunz Michael J. , Hayn Getraud , Saf Robert , Binder Wolfgang H. 
Published: December 2003

AbstractThe preparation of 2,4‐diamino‐1,3,5‐triazine telechelic poly(ether ketone)s (triazine PEKs) and the formation of supramolecular polymers with dodecyl‐(α‐ω)‐bis(5‐methyl‐1,3‐pyrimidine‐2,4‐dione) were investigated. Both structures interacted by complementing hydrogen‐bonding units present at their respective chain ends, this being reminiscent of triple hydrogen bonding in DNA. The preparation of the triazine PEKs started from hydroxyl‐terminated poly(ether ketone)s by a nucleophilic displacement reaction with 2,4‐diamino‐6‐(4‐fluorophenyl)‐1,3,5‐triazine. With this method and molecular weight control via the Carothers equation, a series of triazine PEKs with a complete degree of end‐group functionalization were prepared. The structure of the polymers was proven by 13C NMR spectroscopy and matrix‐assisted laser desorption/ionization spectroscopy. When mixed as a 1:1 complex in solution with dodecyl‐(α‐ω)‐bis(5‐methyl‐1,3‐pyrimidine‐2,4‐dione), short triazine PEKs (molecular weight = 5700 or 10,000) showed a temperature‐dependent association behavior visible via dynamic NMR spectroscopy. Additional proof of the formation of a supramolecular, hydrogen‐bonded network was derived from solid‐state NMR spectroscopy, differential scanning calorimetry, and rheological investigations. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 661–674, 2004
Structure and properties of poly(methyl methacrylate) particles prepared by a modified microemulsion polymerization
Authors: Jiang Wan , Yang Wuli , Zeng Xianbiao , Fu Shoukuan 
Published: December 2003

AbstractNanoscale poly(methyl methacrylate) (PMMA) particles were prepared by modified microemulsion polymerization. Different from particles made by traditional microemulsion polymerization, the particles prepared by modified microemulsion polymerization were multichain systems. PMMA samples, whether prepared by the traditional procedure or the modified procedure, had glass‐transition temperatures (Tg's) greater than 120 °C and were rich in syndiotactic content (55–61% rr). After the samples were dissolved in CHCl3, there were decreases in the Tg values for the polymers prepared by the traditional procedure and those prepared by the modified process. However, a more evident Tg decrease was observed in the former than in the latter; still, for both, Tg was greater than 120 °C. Polarizing optical microscopy and wide‐angle X‐ray diffraction indicated that some ordered regions formed in the particles prepared by modified microemulsion polymerization. The addition of a chain‐transfer agent resulted in a decrease in both the syndiotacticity and Tg through decreasing polymer molecular weight. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 733–741, 2004
Theoretical and experimental X‐ray photoelectron spectroscopy investigation of ion‐implanted nafion
Authors: Hoffmann Eufrozina A. , Fekete Zoltan A. , Korugic‐Karasz Ljiljana S. , Karasz Frank E. , Wilusz Eugene 
Published: December 2003

AbstractThe membrane properties of a Nafion surface can be modified by ion implantation with N+ or F+. The results are presented of an X‐ray photoelectron spectroscopy (XPS) study of implanted surfaces. For the interpretation of the XPS spectra, calculations using a semiempirical quantum chemical formalism (AM1) have been applied, in conjunction with a charge‐potential model, to predict the C1s core electron binding energies. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 551–556, 2004
Aminotelechelics: A convenient synthesis and characterization of primary amino‐terminated telechelic poly(propylene glycol) and polyisobutylene
Authors: Kéki Sándor , Nagy Miklós , Deák György , Herczegh Pál , Zsuga Miklós 
Published: December 2003

AbstractThe synthesis of amino‐terminated telechelic poly(propylene glycol) and polyisobutylene from their corresponding dihydroxy‐terminated derivatives was studied. The synthesis of these aminotelechelics was achieved by the coupling of imidazolylformates with ethylenediamine. The structure of the resulting amino‐functionalized polymers was determined by 1H NMR, 13C NMR, and matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry. On the basis of the spectroscopic and spectrometric results, a complete conversion of dihydroxy termini into diamino end groups was observed; that is, the number‐average functionality was found to be 2. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 587–596, 2004
My life with polymer science
Authors: Vogl Otto 
Published: December 2003

AbstractThis article describes the scientific investigations and accomplishments in the life of the author. After a dissertation on steroids, several years were spent on alkaloids and research on heterocyclic compounds. Much of the author's career was devoted to research on aldehyde polymerization, the discovery of the polymerization of higher aldehydes and their isotactic polymers, and haloaldehyde polymerization. The latter led to our work on the ceiling temperature of polymerization, on new polymerization techniques [involving the ceiling temperature and the concept of macromolecular asymmetry (polymer helicity)], and the genesis of chloral polymerization. Another important period was devoted to functional polymers, polymeric stabilizers, and polymeric drugs. Other research activities included studies of unusual polymers, head‐to‐head polymers, spacer groups in polymers, and oriental lacquers. Attention was also paid to the use of novel and unusual polymer intermediates, polymerization under extreme conditions and the preparation and behavior of uncommon polymer structures. Finally, it was recognized that macromolecules can be categorized with increasing frequency as polymers with broad and narrow molecular weight distributions and uniform polymers. The ultimate unity is isotopically pure uniform polymers, single macromolecular species. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 795–818, 2004