bluuebunny/crossref_metadata_2025_split huggingface dataset:
Change in α‐tocopherol contents, lipid oxidation and fatty acid profile in eggs enriched with linolenic acid or very long‐chain ω3 polyunsaturated fatty acids after different processing methods
Authors: Cortinas Lucía , Galobart Jaume , Barroeta Ana C , Baucells María D , Grashorn Michael A 
Published: May 2003

AbstractThe influences of dietary supplementation with α‐tocopheryl acetate (α‐TA) and of processing (by hard‐boiling and scrambling) of eggs enriched with ω3 fatty acids, either very long‐chain ω3 polyunsaturated fatty acids (VLC ω3 PUFAs) or linolenic acid (LNA), on fatty acid composition, α‐tocopherol content and lipid oxidation (thiobarbituric acid (TBA) values) were studied. Four dietary treatments were formulated from a basal diet containing 40 g kg−1 linseed oil (LO) or fish oil (FO) combined with either 0 or 100 mg α‐TA kg−1 of feed. Eggs from LO treatments were enriched with LNA and those from FO treatments were rich in VLC ω3 PUFAs. Neither processing nor dietary supplementation with α‐TA modified greatly the fatty acid profile of eggs. Dietary supplementation with α‐TA increased the α‐tocopherol content of eggs (187.2 versus 407.9 µg g−1 dry matter). Eggs from FO treatments showed lower α‐tocopherol content than those from LO treatments (273.5 versus 321.6 µg g−1 dry matter), and processing of eggs enriched with VLC ω3 PUFA reduced the α‐tocopherol content by a significant 16%. Moreover, processing of eggs increased lipid oxidation two‐ to nine‐fold. Oxidation levels of hard‐boiled eggs were 30.4% higher than those of scrambled eggs. TBA values in hard‐boiled and scrambled eggs were significantly reduced when 100 mg α‐TA kg−1 of feed supplemented the diet only in those eggs enriched with VLC ω3 PUFA (from FO treatments). Copyright © 2003 Society of Chemical Industry
Monitoring of seed composition of prickly pear (Opuntia ficus‐indica L) fruits during maturation period
Authors: Coşkuner Yalçı n , Tekin Aziz 
Published: May 2003

AbstractPrickly pear fruit seeds were subjected to a range of chemical analyses during their 15 week maturation period. Seeds contained on average 71.5 g kg−1 dry matter, 61.9 g kg−1 crude oil, 9.4 g kg−1 protein, 507.4 g kg−1 crude fibre, 12.3 g kg−1 ash and 409.0 g kg−1 carbohydrate. The fatty acid composition of prickly pear seed oil consisted of 1.3–1.9 g kg−1 myristic (14:0), 132.1–156.0 g kg−1 palmitic (16:0), 14.4–18.5 g kg−1 palmitoleic (16:1), 33.1–47.9 g kg−1 stearic (18:0), 210.5–256.0 g kg−1 oleic (18:1), 522.5–577.6 g kg−1 linoleic (18:2), 2.9–9.7 g kg−1 linolenic (18:3), 4.2–6.6 g kg−1 arachidic (20:0) and 2.1–3.0 g kg−1 behenic (22:0) acids, which is comparable with that of corn oil. No statistical difference in seed weight ratio was determined during the maturation period, whereas changes in the saturated fatty acids of the seed oil were observed. From this study it can be concluded that the seeds of prickly pear are suitable as animal feed. Copyright © 2003 Society of Chemical Industry
Specific determination of cysteine in human urine by capillary micellar electrokinetic chromatography
Authors: Ševčíková Petra , Glatz Zdeněk 
Published: June 2003

AbstractThis paper describes a method for the analysis of cysteine in human urine using capillary micellar electrokinetic chromatography and on‐column reaction with 2,2′‐dipyridyl disulfide. In this reaction cysteine is quantitatively transformed into a mixed disulfide concomitantly with formation of an equimolar amount of 2‐thiopyridone that is further separated by capillary micellar electrokinetic chromatography and determined spectrophotometrically at 343 nm. The concentration of cysteine is thus estimated indirectly from the result of 2‐thiopyridone determination. The linear detection range for concentration versus peak area for the assay is from 0.05 to 5 mM (correlation coefficient 0.989) with a detection limit of 2.5 μM and a limit of quantitation of 8.5 μM. The inter‐day reproducibility of the peak area was 2.18% and the inter‐day reproducibility of the migration time 0.51%. The method is relatively rapid, simple, and can be easily automated. Moreover, its detection limit covers the concentration range at which cysteine is present in biological samples such as human urine.
SPME – A valuable tool for investigation of flower scent
Authors: Barták Petr , Bednář Petr , Čáp Lubomír , Ondráková Lenka , Stránský Zdeněk 
Published: June 2003

AbstractA novel Headspace Solid Phase Microextraction (HS‐SPME) protocol is proposed for the analysis of floral scent. Volatile compounds emitted from the flower are collected on a Carboxen/PDMS fiber for 1 hour, transferred to the GC, and analyzed by GC/MS. The method completely eliminates the use of organic solvents, does not require special instrumentation, and may readily be performed in the field without access to mains electricity and other energy supplies. The method is robust, sensitive, and reduces the sampling stress on the investigated plant. Since enzymatic reactions in living flowers may cause changes in the composition of emitted fragrance, dried rosemary (Rosmarinus officinalis L.) was used as a stable standard for the method development and optimization. In addition, grape wine was also suggested as homogeneous, bio‐compatible, and relatively stable standard of pronounced and typical scent for the same purpose. The optimized method was used for the comparative investigation of the fragrances emitted by two different species – Lathyrus vernus (L.) and Orchis pallens (L.). Several monoterpenes (C10 compounds) were found as the main fragrance components of lathyrus, while sesquiterpenes (C15 compounds) were typical for the orchid.
Determination of the purity of phenoxymethylpenicillin by micellar electrokinetic chromatography and reversed phase liquid chromatography on a monolithic silica column
Authors: Doležalová Milada , Čápová Hana , Jobánek Roman 
Published: June 2003

AbstractA micellar electrokinetic chromatographic and a fast reversed‐phase liquid chromatographic method have been developed for determination of the purity of phenoxymethylpenicillin. The optimized running buffer composition was 40 mM phosphate–borate–125 mM SDS–3.5% (v/v) methanol. The HPLC method employed a monolithic silica C18 column and a mobile phase composed of phosphate buffer, pH 3.5, and ACN, the flow‐rate being 3.5 mL/min. Both methods were successfully validated. Linearity, intermediate precision, limits of quantitation, accuracy, and a good correlation of the HPLC and MEKC results were demonstrated. Both methods proved to be fast and reliable and sufficiently sensitive. A combination of the two methods can be very useful in impurity profiling.
Photooxidation and Photoconductivity of Polyferrocenylsilane Thin Films
Authors: Cyr Paul W. , Tzolov Marian , Manners Ian , Sargent Edward H. 
Published: June 2003

AbstractIrradiation of thin films of poly(ferrocenylmethylphenylsilane) ([Fe(η5‐C5H4)2SiMePh]n) cast from chloroform solution with UV light leads to photooxidation of ferrocene centers in the polymer main chain. The extent of the polymer oxidation can be controlled in the range ca. 0–5% by the duration of the irradiation exposure and by the concentration of chloroform. The photooxidized polyferrocenylsilane material is conductive, with an increased conductivity of greater than three orders of magnitude relative to the unoxidized material. In addition, the photooxidized polymers have been found to be photoconductive. The photooxidation process can be reversed by means of chemical reduction using hydrazine or decamethylferrocene, leading to the regeneration of the neutral polymers. However, substantial molecular weight decline was detected during the photooxidation/reduction process, presumably as a result of chain cleavage reactions induced by the anionic or radical chlorinated photoproducts. Methylation of the cyclopentadienyl rings of the ferrocene moiety in the polymer was found to lead to materials which are significantly more stable.Time trace of the current at constant applied voltage of 100 V for a PFS film upon illumination. The ON and OFF states were created by using a mechanical shutter.magnified imageTime trace of the current at constant applied voltage of 100 V for a PFS film upon illumination. The ON and OFF states were created by using a mechanical shutter.
Synthesis of New Hydrogels by Copolymerization of Poly(2‐methyl‐2‐oxazoline) Bis(macromonomers) and N‐Vinylpyrrolidone
Authors: Rueda Juan C. , Komber Hartmut , Cedrón Juan C. , Voit Brigitte , Shevtsova Galina 
Published: June 2003

AbstractNew non‐ionic hydrogels were synthesized by radical homopolymerization of vinyl end‐functionalized poly(2‐methyl‐2‐oxazoline) bis(macromonomers), or by radical copolymerization of these bis(macromonomers) with N‐vinyl‐2‐pyrrolidone (NVP). The poly(2‐methyl‐2‐oxazoline) bis(macromonomers) were synthesized through “living” cationic ring‐opening polymerization of 2‐methyl‐2‐oxazoline (MeOXA), using, simultaneously, the known “initiating” and “end‐capping” method for synthesis of macromonomers. Chloromethyl styrene was used as initiator and N‐(4‐vinylbenzyl)‐piperazine was used as the terminating agent. Well defined poly(2‐methyl‐2‐oxazoline) bis(macromonomers) were obtained with Pn = 4, 11, and 17. The hydrogel structures were characterized by high‐resolution magic angle spinning NMR technique and their solvent absorption capacity was tested by swelling experiments in different solvents. The bis(macromonomers) were characterized by NMR spectroscopy and gel permeation chromatography.Schematic of polymerizationmagnified imageSchematic of polymerization
Deformation Behavior of PET, PBT and PBT‐Based Thermoplastic Elastomers as Revealed by SAXS from Synchrotron
Authors: Stribeck Norbert , Fakirov Stoyko , Apostolov Anton A. , Denchev Zlatan , Gehrke Rainer 
Published: June 2003

AbstractThe present paper discloses the changes in the nanostructure as revealed by small‐angle X‐ray scattering (SAXS) of synchrotron radiation of anisotropic semi‐crystalline samples of polyester and poly(ether ester) type differing in their chemical composition, while subjected to controlled progressive elongation. From the group of polyesters poly(ethylene terephthalate) (PET), and poly(butylene terephthalate) (PBT) were selected. Two PBT‐based commercial poly(ether ester)s were also studied differing in the molecular weight of their soft segments (poly(tetramethylene glycol), PTMG) being 1000 and 2000, respectively. A blend of PBT and EM550 (40/60 by wt.) was also characterized. All materials underwent the same sample preparation process resulting in highly oriented “bristles” of 1 mm diameter. It was found that εb, the elongation at break, strongly depends on the flexibility of the glycol residues of the materials studied – ranging from εb = 8% for PET that contains ethylene glycol residues, through εb = 18% for PBT including the more flexible tetramethylene glycol (TMG) up to εb = 510% for the PEE containing the longest PTMG moieties. During straining the relationship between the external elongation ε and the changes in the long spacing L was determined. After relaxation from each deformation step the relationship between the tensile set εr and the long period L was also followed and discussed. Such analysis led to a model describing the nanostructure evolution during the deformation‐relaxation cycle that finally was verified and refined utilizing the multidimensional chord distribution function computed from the anisotropic SAXS patterns.2D SAXS patterns (pseudo color) of bristles of PET (PBT), respectively, cold drawn, λ = 3.5 (λ = 2.3) and annealed with fixed ends for 6 h at 240 °C (180 °C), recorded at room temperature at a forced tensile deformation ε or tensile set (residual elongation) εr in percent.magnified image2D SAXS patterns (pseudo color) of bristles of PET (PBT), respectively, cold drawn, λ = 3.5 (λ = 2.3) and annealed with fixed ends for 6 h at 240 °C (180 °C), recorded at room temperature at a forced tensile deformation ε or tensile set (residual elongation) εr in percent.
Hyperbranched Polyalkoxysiloxanes via AB3‐Type Monomers
Authors: Jaumann Manfred , Rebrov Eugene A. , Kazakova Valentina V. , Muzafarov Aziz M. , Goedel Werner A. , Möller Martin 
Published: June 2003

AbstractWe have synthesized polyethoxysiloxanes starting from the AB3‐type monomers triethoxysilanol and acetoxytriethoxysilane. The polymers are liquid and soluble in organic solvents.29Si NMR spectroscopy and MALDI‐ToF mass spectrometry analyses show that the polymers have a hyperbranched structure with additional internal cyclization.29Si NMR spectroscopy indicates that the polymer synthesized from acetoxytriethoxysilane is less branched than the polymer synthesized from triethoxysilanol. Analysis of the molar mass and mass distribution of the polymers via size exclusion chromatography (calibrated via MALDI‐ToF MS and viscosimetry) yields a molar mass ofMn ≈ 2 kg · mol−1andMw ≈ 8 kg · mol−1for polymers synthesized from triethoxysilanol. The molar mass of the polymers synthesized from acetoxytriethoxysilane can be controlled by variation of the polymerization time in the range ofMn ≈ 1.8–12 kg · mol−1andMw ≈ 2.1–2 200 kg · mol−1.Photograph of a vial containing polyethoxysiloxane obtained from triethoxysilanol and a schematic drawing of the proposed molecular structure of the polymer.magnified imagePhotograph of a vial containing polyethoxysiloxane obtained from triethoxysilanol and a schematic drawing of the proposed molecular structure of the polymer.
Poly(ethylene oxide)‐ and Poly(perfluorohexylethyl methacrylate)‐Containing Amphiphilic Block Copolymers: Association Properties in Aqueous Solution
Authors: Hussain Hazrat , Busse Karsten , Kressler Jörg 
Published: June 2003

AbstractAmphiphilic di‐ and triblock copolymers containing poly(ethylene oxide) (PEO) as the hydrophilic block and poly(perfluorohexylethyl methacrylate) (PFMA) as the hydrophobic block were synthesized by atom‐transfer radical polymerization using hydroxy‐terminated PEO as the macroinitiator. The copolymers were characterized by size exclusion chromatography and 1H NMR spectroscopy. Self‐association in aqueous solution has been investigated using surface tension measurements, dynamic light scattering (DLS), and transmission electron microscopy (TEM). From surface tension measurements in water, a characteristic concentration (c*) can be detected, which is interpreted as the critical micelle concentration (cmc). The cmc decreases with an increase in fluoro content in the triblock copolymer up to 11 wt.‐% PFMA (solubility limit). DLS studies have been carried out for different samples above the cmc, showing small aggregates (micelles) and single chains for diblock copolymer solutions. In the case of triblock copolymers large clusters were the dominant aggregates in addition to the micelles and single chains. The effect of temperature and concentration on the micelle and cluster formation has been investigated by DLS. Micelle size was found to be resistant to any change by temperature, however, a slight but significant increase in apparent hydrodynamic radius was observed with an increase in concentration, while both temperature and concentration affected the formation of large clusters, especially in concentrated solutions. TEM has been carried out to visualize the morphology of the aggregates after transferring the solution to carbon film. The initial concentration for the preparation of TEM samples was found to have a strong influence on the morphology of the aggregates. By adding colloidal gold particles to the solutions, the typical covering by the polymer was observed by TEM.Decay‐rate distributions for PEO10F5 (4.0 g · L−1); obtained from the time correlation functions.magnified imageDecay‐rate distributions for PEO10F5 (4.0 g · L−1); obtained from the time correlation functions.
Lack of association between progressive supranuclear palsy and arterial hypertension: A clinicopathological study
Authors: Colosimo Carlo , Osaki Yasushi , Vanacore Nicola , Lees Andrew J. 
Published: May 2003

AbstractIt has been reported that up to 80% of patients clinically diagnosed as having progressive supranuclear palsy (PSP) may have arterial hypertension (HT). Because previous studies were performed on patients with presumed diagnosis of PSP, we tried to replicate these studies in a series of pathologically confirmed patients. Seventy‐three patients with a neuropathological diagnosis of PSP autopsied at the Queen Square Brain Bank for Neurological Disorders in London were collected between 1989 and 1999. For the purpose of this study, patients were considered hypertensive if a blood pressure above 140/90 mm Hg was found in the clinical records. The prevalence of HT in PSP patients at the first and at the last visit during their neurological disease was compared with that found in a series of 21 normal controls who donated their brain to the same institution. Overall, 29 of 73 (39.7%) of the patients were recorded as having HT at the first visit during the disease course; this ratio increased to 42 of 73 (57.5%) at the last visit before death. When these figures were compared to the 21 normal controls (11 of 21 with HT, 52.4%), we were unable to find an increased prevalence of HT in PSP (odds ratio, 0.60; 95% confidence interval, 0.20–1.76). Therefore, HT does not represent an important clinical feature of this neurodegenerative disorder, although cerebrovascular disease can masquerade clinically as PSP. © 2003 Movement Disorder Society
Development and testing of the Parkinson's disease quality of life scale
Authors: Welsh Mickie , McDermott Michael P. , Holloway Robert G. , Plumb Sandy , Pfeiffer Ronald , Hubble Jean 
Published: May 2003

AbstractWe report on the development and results of preliminary psychometric testing of a disease specific health‐related quality of life (HRQoL) scale intended for use in individuals diagnosed with idiopathic Parkinson's disease (PD). Results from an initial qualitative study provided content for item development and scale construction of the Parkinson's disease quality of life scale (PDQUALIF). The 33‐item instrument includes seven domains: social/role function, self‐image/sexuality, sleep, outlook, physical function, independence, and urinary function, plus one item of Global HRQoL. Initial psychometric testing of the instrument was conducted in 233 outpatient clinic attendees with physician‐confirmed idiopathic PD. Factor structure, reliability and validity of the scale have been established in this cross‐sectional study. Continuing development of the PDQUALIF will be directed at enhancing the psychometric properties, establishing responsiveness and determining appropriateness in culturally diverse samples. © 2003 Movement Disorder Society
Cholecystokinin antagonists: Pharmacological and therapeutic potential
Authors: Herranz Rosario 
Published: May 2003

AbstractCholecystokinin (CCK) is a regulatory peptide hormone, predominantly found in the gastrointestinal tract, and a neurotransmitter present throughout the nervous system. In the gastrointestinal system CCK regulates motility, pancreatic enzyme secretion, gastric emptying, and gastric acid secretion. In the nervous system CCK is involved in anxiogenesis, satiety, nociception, and memory and learning processes. Moreover, CCK interacts with other neurotransmitters in some areas of the CNS. The biological effects of CCK are mediated by two specific G protein coupled receptor subtypes, termed CCK1 and CCK2. Over the past fifteen years the search of CCK receptor ligands has evolved from the initial CCK structure derived peptides towards peptidomimetic or non‐peptide agonists and antagonists with improved pharmacokinetic profile. This research has provided a broad assortment of potent and selective CCK1 and CCK2 antagonists of diverse chemical structure. These antagonists have been discovered through optimization programs of lead compounds which were designed based on the structures of the C‐terminal tetrapeptide, CCK‐4, or the non‐peptide natural compound, asperlicin, or derived from random screening programs. This review covers the main pharmacological and therapeutic aspects of these CCK1 and CCK2 antagonist. CCK1 antagonists might have therapeutic potential for the treatment of pancreatic disorders and as prokinetics for the treatment of gastroesophageal reflux disease, bowel disorders, and gastroparesis. On the other hand, CCK2 antagonists might have application for the treatment of gastric acid secretion and anxiety disorders. © 2003 Wiley Periodicals, Inc. Med Res Rev, 23, No. 5, 559–605, 2003
Protease inhibitors of the sulfonamide type: Anticancer, antiinflammatory, and antiviral agents
Authors: Supuran Claudiu T. , Casini Angela , Scozzafava Andrea 
Published: May 2003

AbstractThe sulfonamides constitute an important class of drugs, with several types of pharmacological agents possessing antibacterial, anticarbonic anhydrase, diuretic, hypoglycemic, and antithyroid activity among others. A large number of structurally novel sulfonamide derivatives have ultimately been reported to show substantial protease inhibitory properties. Of particular interest are some metalloprotease inhibitors belonging to this class, which by inhibiting several matrix metalloproteases (MMPs) show interesting antitumor properties. Some of these compounds are currently being evaluated in clinical trials. The large number of sulfonamide MMP inhibitors ultimately reported also lead to the design of effective tumor necrosis factor‐α converting enzyme (TACE) inhibitors, potentially useful in the treatment of inflammatory states of various types. Since both MMPs and TACE contribute synergistically to the pathophysiology of many diseases, such as arthritis, bacterial meningitis, tumor invasion; the dual inhibition of these enzymes emerged as an interesting target for the drug design of anticancer/antiinflammatory drugs, and many such sulfonamide derivatives were recently reported. Human neutrophyl elastase (HNE) inhibitors of the sulfonamide type may also be useful in the treatment of inflammatory conditions, such as emphysema, cystic fibrosis, chronic bronchitis, ischemia reperfusion injury, and acute respiratory distress syndrome. Inhibition of some cysteine proteases, such as several caspase and cathepsin isozymes, may lead to the development of pharmacological agents effective for the management of several diseases, such as rheumatoid arthritis, inflammatory bowel disease, brain damage, and stroke. Another research line that progressed much in the last time regards different sulfonamides with remarkable antiviral activity. Some clinically used HIV protease inhibitors (such as amprenavir) possess sulfonamide moieties in their molecules, which are critical for the potency of these drugs, as shown by means of X‐ray crystallography, whereas a very large number of other derivatives are constantly being synthesized and evaluated in order to obtain compounds with lower toxicity or augmented activity against viruses resistant to the such first generation drugs. Other viral proteases, such as those isolated from several types of herpes viruses may be inhibited by sulfonamide derivatives, leading thus to more effective classes of antiviral drugs. © 2003 Wiley Periodicals, Inc. Med Res Rev, 23, No. 5, 535–558, 2003
Electrically wavelength‐tunable optical short‐pulse generation in a self‐seeding scheme with intensity controllable feedback
Authors: Wang D. N. , Zhang M. 
Published: May 2003

AbstractA simple and robust system is presented to generate electrically wavelength‐tunable optical short pulses from a gain‐switched Fabry–Perot laser diode. The laser external cavity consists of a tunable filter and an erbium‐doped fiber amplifier, which provides wavelength selectivity and intensity controllable feedback. As a result, a side mode suppression ratio SMSR of better than 30 dB over the wavelength tuning range of 17.5 nm can be obtained. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 98–99, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10982