bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development and validation of an HPLC method for the determination of penicillin antibiotics residues in bovine muscle according to the European Union Decision 2002/657/EC
Authors: Samanidou Victoria F. , Nisyriou Styliani A. , Papadoyannis Ioannis N. 
Published: October 2007

AbstractA high‐performance liquid chromatographic method was developed for the determination of five penicillins: penicillin G (PENG), penicillin V (PENV), oxacillin (OX), cloxacillin (CLO), and dicloxacillin (DICLO), in bovine muscle. Samples were macerated with a mixture of H2O/CH3CN (1:1) and purified using RP‐8 Adsorbex SPE cartridges after centrifugation, with mean recovery from spiked samples higher than 89%. The separation of the examined penicillins was achieved on an analytical column, an Inertsil C8 5 μm, 250×4 mm2, at ambient temperature. The mobile phase consisted of 0.1% TFA/ACN 50:50 v/v delivered isocratically at a flow rate of 1.1 mL/min. Analytes were monitored at 240 nm. The procedure was validated according to the European Union Decision 2002/657/EC by means of selectivity, stability, decision limit, detection capability, accuracy, and precision. Method's LOQ values achieved were 54 μg/kg for PENG and DICLO, 46 μg/kg for PENV, 16 μg/kg for OX, and 43 μg/kg for DICLO. The detection capabilities (CCβ) were 73.6 μg/kg for PENG, 29.1 μg/kg for PENV, 350.6 μg/kg for OX, 379.9 μg/kg for CLO, and 355.8 μg/kg for DICLO. The method was applied to various samples from the local market. Two penicillins were identified by photodiode array (PDA) detection and quantified.
Analysis of phenolic acids in fruits by HPLC with monolithic columns
Authors: Biesaga Magdalena , Ochnik Urszula , Pyrzynska Krystyna 
Published: October 2007

AbstractReversed‐phase HPLC was optimised for simultaneous determination of several derivatives of benzoic and hydroxycinnamic acids (so‐called phenolic acids) in plums using a commercially available monolithic column. Mobile phase pH and concentration of organic modifier (methanol and acetonitrile) were tested in order to obtain the best resolution. Satisfactory separation was achieved in gradient mode with a mobile phase consisting of 50 mM phosphate buffer at pH 2.2 (solvent A) and acetonitrile (solvent B). The limits of detection for a UV detector ranged between 0.098 and 2.04 μg/mL for vanillic acid and p‐hydroxyphenylacetic acid, respectively. The developed method was used for monitoring the content of polyphenolic acids in plums during their ripening process. The presence of these constituents was confirmed by checking their MS spectra.
Preparation of methacrylate monoliths
Authors: Vlakh Evgenia G. , Tennikova Tatiana B. 
Published: October 2007

AbstractRigid macroporous polymers developed in the early 1990s are widely used as efficient stationary phases for all types of chromatographic separations. The main advantages of so‐called monolithic supports are their high hydraulic permeability and the dominance of the convection over the diffusion mechanism of mass‐exchange under dynamic conditions that allow the separation to be carried out at extremely high flow rates and, consequently, during very short operation times. Among other types of macroporous polymers, the methacrylate‐based monolithic materials represent the most popular and successfully explored class of sorbents. This review is an attempt to collect together the contributions of different groups working in the area of monolith preparation. Examples of different methcrylate monomers and crosslinkers, as well as porogenic solvents, including polymer ones, used in monolith preparation are discussed.
Separation and determination of five major opium alkaloids with mixed mode of hydrophilic/cation‐exchange monolith by pressurized capillary electrochromatography
Authors: Lin Xucong , Wang Jiabin , Li Liyu , Wang Xiaochun , Lü Haixia , Xie Zenghong 
Published: October 2007

AbstractA method for the separation and determination of five major opium alkaloids (narcotine, papaverine, thebaine, codeine, and morphine) in pericarpium papaveris by pressurized CEC (pCEC) with monolithic column has been developed. Under the optimum condition, linear calibration ranges of narcotine, papaverine, thebaine, codeine, and morphine were obtained as 2–85, 2–85, 5–75, 10–65, and 10–65 μg/mL, respectively. LODs of these analytes were 1.5–6.0 μg/mL. The RSD (n = 7) of the migration time and peak area were 1.94–5.24 and 4.05–8.21%, respectively. The proposed method was successfully applied to the analysis of pericarpium papaveris samples. Average recoveries of 79.0–95.9% at different fortified levels of alkaloids were achieved with RSD less than 4.6%. Meanwhile, the mechanism of the separation of the alkaloids on the monolithic column was also discussed. The result showed that the separation of alkaloids was mainly based on the mixed mode of hydrophilic interaction (HI) and cation exchange.
Real space observation of silica monoliths in the formation process
Authors: Saito Haruko , Kanamori Kazuyoshi , Nakanishi Kazuki , Hirao Kazuyuki 
Published: October 2007

AbstractThe macropore structure evolution of a silica monolith during the formation process was observed by laser scanning confocal microscopy (LSCM) for two kinds of systems. The obtained LSCM images were further subjected to image analysis, and the geometrical parameters were calculated. On the basis of the parameters obtained, improved compositions for high efficiency preparation of macroporous monoliths are discussed.
CEC separation of aromatic compounds and proteins on hexylamine‐functionalized N‐acryloxysuccinimide monoliths
Authors: Carbonnier Benjamin , Guerrouache Mohamed , Denoyel Renaud , Millot Marie‐Claude 
Published: October 2007

AbstractReactive organic polymer monoliths were prepared in fused‐silica capillaries by UV‐initiated free radical polymerization of N‐acryloxysuccinimide (NAS) as reactive monomer, ethylene dimethacrylate as crosslinker, azobisisobutyronitrile as initiator, and toluene as porogen. In a second synthetic step, chemical derivatization of the activated‐ester moieties was performed in situ through alkylation reaction with alkylamines to afford monolithic stationary phases with potential reversed‐phase properties. A correlation between the synthesis conditions – composition of the reactive solution – chemical characteristics of the reactive polymer monoliths – nitrogen/NAS content – and the reversed‐phase separation properties of the functionalized monolithic columns – selectivity towards homologous series of akylbenzenes – was clearly established. This finding offers the possibility of adjusting the experimental conditions with respect to the target applications. The monolithic stationary phases with optimized chemical and porous structures were used for the CEC separation of alkylbenzenes, phenols, anilines, organic acids, amino acids, and proteins. The data indicate that depending on the nature of the analytes (charge, hydrophobic/hydrophilic balance, size) reversed‐phase or mixed modes may account for the observed separation.
Structural monitoring in advanced bridge engineering
Authors: Tesar Alexander , Melcer Jozef 
Published: October 2007

AbstractDynamic identification and monitoring of bridges are dealt with in this paper. Theoretical, numerical and experimental in situ assessments of the problem are presented. Numerical analysis of the monitoring and testing suggested is based on the adoption of the wave approaches. A structural application in situ on attractive cable‐stayed bridge adopting the monitoring approaches suggested is submitted. Copyright © 2007 John Wiley & Sons, Ltd.
Culture or cult? The mythological nature of occupational therapy
Authors: Kelly Greg , Mcfarlane Heather 
Published: October 2007

AbstractThe willingness of occupational therapists to act on their shared beliefs and values has created knowledge and techniques that have been handed down from generation to generation, and, thus, have entered into what might be called the ‘mythology’ of occupational therapy. These myths arose from a set of shared philosophical assumptions that provided a sense of cultural identity. In the present article the authors compare the occupational therapy process to a mythical hero's journey in which the occupational therapist uses narrative reasoning to guide the client (the hero) through a rite of passage to a kind of rehabilitative rebirth. By structuring therapy as an unfolding story, the occupational therapist creates personal myths for his or her clients. Unfortunately, there is a darker side to this process in which cultural identity distorts into membership of a ‘cult’, wherein expert practitioners become ‘priests’ or ‘monks’ possessing secret knowledge that cannot be readily explained to others, especially those from different cultures. It is argued that, by reflecting on and interacting with other cultures through shared mythologies, occupational therapists can learn to amend their values and beliefs accordingly. Myths could bring a sense of cohesiveness to a culture in which ‘truth’ is seen through these shared mythologies. Copyright © 2007 John Wiley & Sons, Ltd.
Physics Fights in Seoul. Das International Young Physicists' Tournament
Authors: Welzel Manuela , Lehn Rudolf 
Published: October 2007

AbstractVom 5. bis 12. Juli 2007 fand in Seoul das International Young Physicists' Tournament statt. Diese Veranstaltung fand in der koreanischen Öffentlichkeit und bei Politikern ein außergewöhnlich großes Interesse. Die gestellten Physikaufgaben verlangen sowohl bei der Vorbereitung als auch beim Turnier selbst intensive Teamarbeit. Das IYPT ist ein gelungenes Beispiel, wie Begabtenförderung aussehen kann.
Der Paranuss‐Effekt
Authors: Ulrich Stephan , Schröter Matthias 
Published: October 2007

AbstractGranulare Medien, wie Sand, Salz, Kohle oder Kaffeebohnen, lassen sich durch vertikales Schütteln entmischen. In Abhängigkeit von der Schüttelamplitude sammeln sich die größeren Teilchen entweder an der Oberfläche (der sogenannte Paranuss‐Effekt), oder sie sinken nach unten (inverser Paranuss‐Effekt). Mit Experimenten, Computersimulationen und Theorie ist es jüngst gelungen, die zu diesem Verhalten führenden Mechanismen zu identifizieren.
Obsessive Präzision
Authors: Jacobi Manfred 
Published: October 2007

AbstractIm Jahr 1907 erhielt Albert Abraham Michelson (1852‐1931) als erster amerikanischer Physiker den Nobelpreis für “seine optischen Präzisionsinstrumente und seine damit ausgeführten Untersuchungen auf dem Gebiet der Präzisionsmetrologie und der Spektroskopie.”
An alternate sucrose binding mode in the E203Q Arabidopsis invertase mutant: An X‐ray crystallography and docking study
Authors: Mátrai Janka , Lammens Willem , Jonckheer Abel , Le Roy Katrien , Rabijns Anja , Van den Ende Wim , De Maeyer Marc 
Published: October 2007

AbstractIn the present study, we report on the X‐ray crystallographic structure of a GH32 invertase mutant, (i.e., the Arabidopsis thaliana cell‐wall invertase 1‐E203Q, AtcwINV1‐mutant) in complex with sucrose. This structure was solved to reveal the features of sugar binding in the catalytic pocket. However, as demonstrated by the X‐ray structure the sugar binding and the catalytic pocket arrangement is significantly altered as compared with what was expected based on previous X‐ray structures on GH‐J clan enzymes. We performed a series of docking and molecular dynamics simulations on various derivatives of AtcwINV1 to reveal the reasons behind this modified sugar binding. Our results demonstrate that the E203Q mutation introduced into the catalytic pocket triggers conformational changes that alter the wild type substrate binding. In addition, this study also reveals the putative productive sucrose binding modus in the wild type enzyme. Proteins 2008. © 2007 Wiley‐Liss, Inc.
Influence of oligomerization on the dynamics of G‐protein coupled receptors as assessed by normal mode analysis
Authors: Niv Masha Y. , Filizola Marta 
Published: October 2007

AbstractThe recently discovered impact of oligomerization on G‐protein coupled receptor (GPCR) function further complicates the already challenging goal of unraveling the molecular and dynamic mechanisms of these receptors. To help understand the effect of oligomerization on the dynamics of GPCRs, we have compared the motion of monomeric, dimeric, and tetrameric arrangements of the prototypic GPCR rhodopsin, using an approximate—yet powerful—normal mode analysis (NMA) technique termed elastic network model (ENM). Moreover, we have used ENM to discriminate between putative dynamic mechanisms likely to account for the recently observed conformational rearrangement of the TM4,5‐TM4,5 dimerization interface of GPCRs that occurs upon activation. Our results indicate: (1) significant perturbation of the normal modes (NMs) of the rhodopsin monomer upon oligomerization, which is mainly manifested at interfacial regions; (2) increased positive correlation among the transmembrane domains (TMs) and between the extracellular loop (EL) and TM regions of the rhodopsin protomer; (3) highest interresidue positive correlation at the interfaces between protomers; and (4) experimentally testable hypotheses of differential motional changes within different putative oligomeric arrangements. Proteins 2008. © 2007 Wiley‐Liss, Inc.
Angiotension‐II receptor blockers: their place in hypertension
Authors: Alem Manal , Elliott Henry 
Published: October 2007

AbstractAngiotensin‐II receptor blockers are now established as a major new class of drugs in the management of hypertension. Our Drug Review considers their properties and efficacy, followed by an analysis of prescription data, sources of further information and the Datafile of available preparations. Copyright © 2007 Wiley Interface Ltd
Enzyme immobilization in latex dispersion coatings for active food packaging
Authors: Nestorson A. , Neoh K. G. , Kang E. T. , Järnström L. , Leufvén A. 
Published: October 2007

AbstractCarboxylated styrene acrylate latex samples have been functionalized by the immobilization and entrapment of the enzyme glucose oxidase (GOx), which can be used as an oxygen scavenger in food packaging. GOx was covalently immobilized both on the surface of already formed films and on the latex particles in dispersion, as well as entrapped within the polymer matrix. In the latter two cases, polymer films were formed after the enzyme had been added to the latex dispersion. The storage stability of the enzyme and the influence of adding clay were also studied. For a given amount of enzyme, the enzyme immobilized on the film surface showed an enzyme activity about 10 times higher than that of the enzyme present within the polymer matrix. This is probably due to the diffusion limitations of the substrate in the polymer matrix. The films with the enzyme present within the polymer matrix, however, showed a higher total oxygen‐removal capacity than films with the enzyme immobilized on the surface. Entrapped enzyme showed a slightly higher activity than enzyme immobilized in the dispersion due to the negative effect of the activating chemicals used during the immobilization and on conformational constraints upon covalent bonding. Low amounts of clay added to the dispersion decreased the enzyme activity, but with higher amounts of clay the enzyme activity increased, probably because of the increased porosity and thus higher substrate accessibility. The most suitable storage condition for all the enzyme‐containing films was +8°C, which is just above the glass transition temperature of the polymer used. Copyright © 2007 John Wiley & Sons, Ltd.
A simple model for the interaction between water vapour and oxygen transmission in multilayer barrier materials intended for food packaging applications
Authors: Jakobsen Marianne , Risbo Jens 
Published: October 2007

AbstractThe low oxygen permeability of the ethylene‐vinyl alcohol copolymer, EVOH, is outstanding, but is also known to be very sensitive to moisture uptake and cannot be used as a monolayer packaging material. In this paper, theory is presented in order to calculate the average water activity of the EVOH layer at steady state and the corresponding oxygen barrier for different multilayer structures using various polymer types and layer thicknesses. Multilayer materials can be designed for different food packaging applications and storage conditions, in order to keep the relative humidity of the barrier below recommended 75%, by varying the thickness of the outside versus the inside protective layers and/or varying the water vapour transmission rate of the outside versus the inside layer. The conclusion reached is that to retain the optimal barrier properties and thereby the optimal protection of the food, asymmetric multilayer structures are necessary. Copyright ©2007 John Wiley & Sons, Ltd.
Implementation of a constant‐time dynamic storage allocator
Authors: Masmano M. , Ripoll I. , Real J. , Crespo A. , Wellings A. J. 
Published: October 2007

AbstractThis paper describes the design criteria and implementation details of a dynamic storage allocator for real‐time systems. The main requirements that have to be considered when designing a new allocator are concerned with temporal and spatial constraints. The proposed algorithm, called TLSF (two‐level segregated fit), has an asymptotic constant cost,O(1), maintaining a fast response time (less than 200 processor instructions on a x86 processor) and a low level of memory usage (low fragmentation). TLSF uses two levels of segregated lists to arrange free memory blocks and anincomplete searchpolicy. This policy is implemented with word‐size bitmaps and logical processor instructions. Therefore, TLSF can be categorized as a good‐fit allocator. The incomplete search policy is shown also to be a good policy in terms of fragmentation. The fragmentation caused by TLSF is slightly smaller (better) than that caused by best fit (which is one of the best allocators regarding memory fragmentation). In order to evaluate the proposed allocator, three analyses are presented in this paper. The first one is based on worst‐case scenarios. The second one provides a detailed consideration of the execution cost of the internal operations of the allocator and its fragmentation. The third analysis is a comparison with other well‐known allocators from the temporal (number of cycles and processor instructions) and spatial (fragmentation) points of view. In order to compare them, a task model has been presented. Copyright © 2007 John Wiley & Sons, Ltd.
Crosslinking of PVC formulations treated with UV light. II. Color formation and viscoelastic properties
Authors: Benavides R. , Arias G. , Castillo E. L. , Téllez M. M. 
Published: October 2007

AbstractTwo wire coating PVC formulations stabilized with Ca/Zn systems and one stabilized with a traditional lead compound were prepared. All three formulations contained trimethylolpropane trimethacrylate (TMPTMA) as a crosslinking agent and Irgacure 819 as a UV photoinitiator. Small specimens of hot‐pressed materials with 1.0 and 1.5 mm thicknesses were irradiated with UV light for 10 days, while monitoring changes at different time intervals. The presence of TMPTMA in the samples influenced the coloration of the lead‐stabilized formulation, while the others experienced the usual color formation after UV treatment, as seen by Yellowing Index measurements and corroborated by the evaluation of fluorescence spectra. The elastic modulus (E′) determined by DMA was shown to be sensitive to surface changes associated with crosslinking, while the loss modulus (E″) determined by DMA and the complex modulus (E*) obtained by TMA were shown to be sensitive indicators of bulk property changes. J. VINYL ADDIT. TECHNOL., 13:189–194, 2007. © 2007 Society of Plastics Engineers
Synthesis and characterization of a bisbenzotriazole derivative and its application in PVC as an ultraviolet absorber
Authors: Xu Sheyang , Cao Derong , Chen Mingcai 
Published: October 2007

AbstractA novel ultraviolet (UV) absorber, 5,5′‐disulfide‐bis[2‐(2‐hydroxy‐3,5‐di‐tert‐butylphenyl)‐2Hbenzotriazole] (DSBHTBB) was synthesized. Its structure was characterized by FTIR, NMR, UV, FABMS, and elemental analysis. In comparison with the common commercial benzotriazole UV absorbers, the absorption maximum of DSBHTBB (364 nm) is red shifted by about 20 nm, and the molar extinction coefficient (56,800, in CHCl3) is much greater. With those properties the bisbenzotriazole could be applied as an efficient UV absorber for the protection of polymeric materials and sensitive skin from longer‐wavelength (near‐visible) ultraviolet light. The experimental results showed that DSBHTBB can greatly inhibit the discoloration under irradiation of poly (vinyl chloride) (PVC) containing an organic antimony stabilizer. J. VINYL ADDIT. TECHNOL., 13:195–200, 2007. © 2007 Society of Plastics Engineers
Soil carbon storage, litterfall and CO2 efflux in fertilized and unfertilized larch (Larix leptolepis) plantations
Authors: Kim Choonsig 
Published: October 2007

AbstractThis study evaluated the effects of forest fertilization on the forest carbon (C) dynamics in a 36‐year‐old larch (Larix leptolepis) plantation in Korea. Above‐ and below‐ground C storage, litterfall, root decomposition and soil CO2 efflux rates after fertilization were measured for 2 years. Fertilizers were applied to the forest floor at rates of 112 kg N ha−1 year−1, 75 kg P ha−1 year−1 and 37 kg K ha−1 year−1 for 2 years (May 2002, 2003). There was no significant difference in the above‐ground C storage between fertilized (41.20 Mg C ha−1) and unfertilized (42.25 Mg C ha−1) plots, and the C increment was similar between the fertilized (1.65 Mg C ha−1 year−1) and unfertilized (1.52 Mg C ha−1 year−1) plots. There was no significant difference in the soil C storage between the fertilized and unfertilized plots at each soil depth (0–15, 15–30 and 30–50 cm). The organic C inputs due to litterfall ranged from 1.57 Mg C ha−1 year−1 for fertilized to 1.68 Mg C ha−1 year−1 for unfertilized plots. There was no significant difference in the needle litter decomposition rates between the fertilized and unfertilized plots, while the decomposition of roots with 1–2 mm diameters increased significantly with the fertilization relative to the unfertilized plots. The mean annual soil CO2 efflux rates for the 2 years were similar between the fertilized (0.38 g CO2 m−2 h−1) and unfertilized (0.40 g CO2 m−2 h−1) plots, which corresponded with the similar fluctuation in the organic carbon (litterfall, needle and root decomposition) and soil environmental parameters (soil temperature and soil water content). These results indicate that little effect on the C dynamics of the larch plantation could be attributed to the 2‐year short‐term fertilization trials and/or the soil fertility in the mature coniferous plantation used in this study.
A preliminary report on the vegetation zonation of palsas in the Arctic National Wildlife Refuge, northern Alaska, USA
Authors: Tsuyuzaki Shiro , Sawada Yuki , Kushida Keiji , Fukuda Masami 
Published: October 2007

AbstractWe measured vegetation patterns on palsas with reference to topographic characteristics on the Arctic National Wildlife Refuge, northern Alaska, to obtain benchmark data because of the changes expected from global warming. Vegetation was examined in 60 plots of area 50 cm × 50 cm by five environmental factors: water content in the peat and duff layers, groundwater level, slope angle, depth to frozen surface, and presence of pellets and feces. Three palsas were selected for the survey, and the heights were fewer than 50 cm from the groundwater surface. Based on TWINSPAN and canonical correspondence analysis, we confirmed that clear patterns of vegetation zonation had developed within a 60‐cm difference in water level. Vaccinium vitis‐idaea occurred well on the top areas of palsas, while Carex aquatilis was established on the bottom areas. Sphagnum spp. were established on intermediate locations between V. vitis‐idaea and C. aquatilis. The prime determinant of the vegetation zonation seems to be water content in peat and duff layers rather than water level, although the five factors that we examined interact intricately with each other.