bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studying the emerging global brain: Analyzing and visualizing the impact of co‐authorship teams
Authors: Börner Katy , Dall'Asta Luca , Ke Weimao , Vespignani Alessandro 
Published: April 2005

AbstractThis article introduces a suite of approaches and measures to study the impact of co‐authorship teams based on the number of publications and their citations on a local and global scale. In particular, we present a novel weighted graph representation that encodes coupled author‐paper networks as a weighted co‐authorship graph. This weighted graph representation is applied to a dataset that captures the emergence of a new field of science and comprises 614 articles published by 1036 unique authors between 1974 and 2004. To characterize the properties and evolution of this field, we first use four different measures of centrality to identify the impact of authors. A global statistical analysis is performed to characterize the distribution of paper production and paper citations and its correlation with the co‐authorship team size. The size of co‐authorship clusters over time is examined. Finally, a novel local, author‐centered measure based on entropy is applied to determine the global evolution of the field and the identification of the contribution of a single author's impact across all of its co‐authorship relations. A visualization of the growth of the weighted co‐author network, and the results obtained from the statistical analysis indicate a drift toward a more cooperative, global collaboration process as the main drive in the production of scientific knowledge. © 2005 Wiley Periodicals, Inc. Complexity 10: 57–67, 2005
Influence of preparation conditions on the properties of Eudragit microspheres produced by a double emulsion method
Authors: Sipos Péter , Csóka Ildikó , Srčič Stane , Pintye‐Hódi Klára , Erős István 
Published: April 2005

AbstractThe aim of the present work was to study the preparation and characteristics of sustained‐release microspheres. As a model drug, sodium diclofenac was encapsulated in microspheres of the polymer Eudragit RS by using a double emulsion–solvent evaporation method. Investigations were carried out on the effects of the preparation method, the rate of the first step of emulsification, and the phase volume and composition (drug and additives) on the physical parameters of the product: its drug encapsulation, and the drug release. We evaluated the resulting microsphere structure [by differential scanning calorimetry (DSC)], the particle size, the surface area (by scanning electron microscopy), the entrapment and encapsulation efficiency (applying a novel method, energy‐dispersive x‐ray fluorescence analysis), the viscosity of the primary emulsion, and the organic solvent residue (by gas chromatography). We also evaluated and compared the samples by means of the kinetic data relating to drug release. The particle size could be decreased to one third by increasing the external aqueous phase ratio. In the first step of emulsification, elevation of the stirring rate led to microspheres with unfavorable characteristics. Increase of the active agent content and the plasticizer concentration had opposite effects. We applied a covalently not bound plasticizer, which was shown to influence the structure of the microspheres considerably. Drug Dev. Res. 64:41–54, 2005. © 2005 Wiley‐Liss, Inc.
Physicochemical Properties of Oosporein, the Major Secreted Metabolite of the Entomopathogenic Fungus Beauveria brongniartii
Authors: Seger Christoph , Erlebach Daniela , Stuppner Hermann , Griesser Ulrich J. , Strasser Hermann 
Published: April 2005

AbstractOosporein (1) is the major secondary metabolite excreted by Beauveria brongniartii (Sacc.) Petch (Ascomycota: Clavicipitaceae), an entomopathogenic fungus infesting the larvae of Melolontha melolontha L. (Coleoptera: Scarabaeidae; common European cockchafer). Physicochemical parameters were established to allow a better understanding of the spatiotemporal distribution of this marker substance in the environment. i) The dependence of the oosporein solubility (Cs) from proton concentration and temperature was assessed. Oosporein is a rather strong organic acid. The basal solubility of oosporein (C in aqueous citrate/HCl buffer at pH 1.23) was found to be 24.8±0.3 μM. The pKa of the first deprotonation step was determined to be 2.42±0.02. A nonlinear van't Hoff equation was established for the temperature dependency of the oosporein solubility (lnCs=a+bT−1+clnT, with a=−123.3, b=2678.9, and c=19.5). ii) A second and third deprotonation step was found in Britton–Robinson‐buffered aqueous solution. The associated pKa values were determined as 6.79±0.08 and 9.19±0.03. iii) The stability of oosporein at different pH values and temperatures was addressed. Oosporein degraded quickly under moderate alkaline conditions and with increased temperatures. The half‐life dropped below 20 h at pH≥8.0 and T≥43°. The analysis of the Arrhenius plot allowed to calculate the activation energies (Ea) as 102±17 (pH 6), 100±5 (pH 8), and 91±6 kJ/mol (pH 10). iiii) The octanol/water partition coefficient (PO) and its pH dependence were also determined. The distribution coefficient (DO) for oosporein at pH 1.2 was found to be 53.7±4.1 (logDO=1.73±0.03). The partition coefficient PO for undissociated oosporein was calculated as 56.6 (logPO=1.75). From the physicochemical properties, it can be concluded that oosporein can hardly be adsorbed by organisms.
Potential Anti‐Inflammatory Activities of Bractelactone and other Compounds Isolated from Fissistigma bracteolatum
Authors: Lan Yu‐Hsuan , Chia Yi‐Chen , Chang Fang‐Rong , Hwang Tsong‐Long , Liaw Chih‐Chaung , Wu Yang‐Chang 
Published: April 2005

AbstractFrom the stems of Fissistigma bracteolatum, a novel natural product with an unprecedented skeleton, bractelactone (1), was isolated, together with four known compounds: piperolactam A (2), aristololactam BIII (3), aristololactam BII (4), and fissilandione (5). The structure of 1 was established on the basis of spectroscopic data as (3Z)‐6,7‐dihydroxy‐4‐methoxy‐3‐(phenylmethylidene)‐5‐(3‐phenylpropanoyl)‐1‐benzofuran‐2(3H)‐one. This compound may be derived from a hybrid of a chalcone and a cinnamic acid, or from a degradation product of a dichalcone. Compounds 1, 2, and 5 showed inhibitory effects on NO generation by RAW264.7 macrophages in response to lipopolysaccharide. Compounds 2 and 5 showed inhibitory effects on formyl‐L‐methionyl‐L‐leucyl‐L‐phenylalanine (fMLP)‐induced superoxide anion (O$\rm{_{2}^{{^\cdot} -}}$) generation in human neutrophils.
Sediment delivery from agricultural land to rivers via subsurface drainage
Authors: Chapman A. S. , Foster I. D. L. , Lees J. A. , Hodgkinson R. A. 
Published: April 2005

AbstractDiffuse sources of sediment and sediment‐associated nutrients are of increasing environmental concern because of their impacts on receiving water courses. The aim of the research reported here was to monitor the outflow from four field (land) drains at two farms in the English Midlands in order to estimate the quantity of sediment delivered to the local rivers and the most likely sources and processes involved. A multiparameter sediment unmixing model was employed, using environmental magnetic, geochemical and radionuclide tracers in order to determine the most likely origin of sediments transported through the drains. Results demonstrated that there was a generally linear relationship between drainflow sediment loss and drainflow volume and that the majority (>70%) of the sediment exported from the drains was derived from topsoil. Macropore flow through heavily cracked soils is supported by the data to be the most likely means of sediment delivery to the drains. In one catchment, drains contributed over 50% of the annual sediment budget. Spatial and temporal variations in the sources of sediment reaching one drain outlet were investigated in detail. A link between soil moisture deficit (SMD) and the frequency of high‐intensity rainfall events was used to explain the appearance and persistence of a new sediment source in this drain after October 1998. It is concluded that field drains have the potential to be significant conduits of sediment and agrochemicals in a wide variety of environments in the UK. It is also suggested that this potential may increase if projected climate change leads to more intense rainfall events and increases in SMD across a greater area of the UK. Copyright © 2005 John Wiley & Sons, Ltd.
Retracted and replaced: A modelling study of hyporheic exchange pattern and the sequence, size, and spacing of stream bedforms in mountain stream networks, Oregon, USA
Authors: Gooseff Michael N. , Anderson Justin K. , Wondzell Steven M. , LaNier Justin , Haggerty Roy 
Published: April 2005

AbstractThis article has been retracted and replaced. See Retraction and Replacement Notice DOI: 10.1002/hyp.6350Studies of hyporheic exchange flows have identified physical features of channels that control exchange flow at the channel unit scale, namely slope breaks in the longitudinal profile of streams that generate subsurface head distributions. We recently completed a field study that suggested channel unit spacing in stream longitudinal profiles can be used to predict the spacing between zones of upwelling (flux of hyporheic water into the stream) and downwelling (flux of stream water into the hyporheic zone) in the beds of mountain streams. Here, we use two‐dimensional groundwater flow and particle tracking models to simulate vertical and longitudinal hyporheic exchange along the longitudinal axis of stream flow in second‐, third‐, and fourth‐order mountain stream reaches. Modelling allowed us to (1) represent visually the effect that the shape of the longitudinal profile has on the flow net beneath streambeds; (2) isolate channel unit sequence and spacing as individual factors controlling the depth that stream water penetrates the hyporheic zone and the length of upwelling and downwelling zones; (3) evaluate the degree to which the effects of regular patterns in bedform size and sequence are masked by irregularities in real streams. We simulated hyporheic exchange in two sets of idealized stream reaches and one set of observed stream reaches. Idealized profiles were constructed using regression equations relating channel form to basin area. The size and length of channel units (step size, pool length, etc.) increased with increasing stream order. Simulations of hyporheic exchange flows in these reaches suggested that upwelling lengths increased (from 2·7 m to 7·6 m), and downwelling lengths increased (from 2·9 m to 6·0 m) with increase in stream order from second to fourth order. Step spacing in the idealized reaches increased from 5·3 m to 13·7 m as stream size increased from second to fourth order. Simulated upwelling lengths increased from 4·3 m in second‐order streams to 9·7 m in fourth‐order streams with a POOL–RIFFLE–STEP channel unit sequence, and increased from 2·5 m to 6·1 m from second‐ to fourth‐order streams with a POOL–STEP–RIFFLE channel unit sequence. Downwelling lengths also increased with stream order in these idealized channels. Our results suggest that channel unit spacing, size, and sequence are all important in determining hyporheic exchange patterns of upwelling and downwelling. Though irregularities in the size and spacing of bedforms caused flow nets to be much more complex in surveyed stream reaches than in idealized stream reaches, similar trends emerged relating the average geomorphic wavelength to the average hyporheic wavelength in both surveyed and idealized reaches. Copyright © 2005 John Wiley & Sons, Ltd.
Content‐aware full search scheme for motion estimation
Authors: Huang Shih‐Yu 
Published: April 2005

AbstractTaking into consideration computational complexity and design regularity, this article proposes a content‐aware full search (CAFS) block matching scheme for motion estimation. Full search (FS) is widely employed in hardware design of block matching because of its regular data flow. But the huge computational complexity of FS makes it infeasible especially in low‐power environments. To reduce the required computational complexity, CAFS using a content‐aware computation allocation mechanism dynamically distributes computation to blocks with distinct motion content based on center‐biased distribution characteristics of motion vectors. Because all operations of CAFS can be performed by a series of ±2 FSs, the hardware of CAFS can be easily extended by the design of FS. Experimental results indicates that CAFS can achieve about 0.5–1.4 dB quality improvement over original FS in football and table tennis sequences under the same computation. © 2005 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 14, 246–252, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ima.20028
Holographic digital Fourier microscopy for selective imaging of biological tissue
Authors: Alexandrov Sergey A. , Meredith P. , McIntyre T. J. , Zvyagin A. V. 
Published: April 2005

AbstractWe present an application of digital Fourier holography for selective imaging of scatterers with different sizes in turbid media such as biological tissues. A combination of Fourier holography and high‐resolution digital recording, digital Fourier microscopy (DFM) permits crucial flexibility in applying filtering to highlight scatterers of interest in the tissue. The high‐resolution digital hologram is a result of the collation of Fourier holographic frames to form a large‐size composite hologram. It is expected that DFM has an improved signal‐to‐noise ratio as compared to conventional direct digital imaging, e.g., phase microscopy, as applied to imaging of small‐size objects. The demonstration of the Fourier filtering capacity of DFM using a biological phantom represents the main focus of this article. © 2005 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 14, 253–258, 2004; Published online inWiley InterScience (www.interscience.wiley.com). DOI 10.1002/ima.20031
An accurate relativistic universal Gaussian basis set for hydrogen through Nobelium without variational prolapse and to be used with both uniform sphere and Gaussian nucleus models
Authors: Haiduke Roberto L. A. , de Macedo Luiz G. M. , da Silva Albérico B. F. 
Published: April 2005

AbstractAn accurate relativistic universal Gaussian basis set (RUGBS) from H through No without variational prolapse has been developed by employing the Generator Coordinate Dirac–Fock (GCDF) method. The behavior of our RUGBS was tested with two nuclear models: (1) the finite nucleus of uniform proton‐charge distribution, and (2) the finite nucleus with a Gaussian proton‐charge distribution. The largest error between our Dirac–Fock–Coulomb total energy values and those calculated numerically is 8.8 mHartree for the No atom. © 2005 Wiley Periodicals, Inc. J Comput Chem 26: 932–940, 2005
Prediction of numbing and effortful avoidance in female rape survivors with chronic PTSD
Authors: Feuer Catherine A. , Nishith Pallavi , Resick Patricia 
Published: April 2005

AbstractThe purpose of the present study was to investigate the relationships among numbing, arousal, intrusion, and avoidance in a sample of 272 female rape survivors. Multiple regression analyses were conducted to test a theoretical model, which posits that hyperarousal and numbing are functionally related mechanisms and intrusions and avoidance are functionally related. Results supported the hypothesis that arousal explained the majority of the variance in numbing beyond that explained by avoidance and intrusion. In addition, intrusive symptoms explained the majority of the variance in effortful avoidance beyond that explained by numbing and arousal. The findings suggest that numbing and effortful avoidance may be separate mechanisms associated with symptoms of arousal and intrusion, respectively.
Synthesis and Hydrolysis of α,ω‐Perfluoroalkyl‐Functionalized Derivatives of Poly(ethylene oxide)
Authors: Amado Elkin , Kressler Jörg 
Published: April 2005

AbstractSummary: Two series of novel α,ω‐perfluoroalkyl terminated esters of poly(ethylene oxide) (PEO) (RF‐PEO) having the general structure CmF2m+1COO(CH2CH2O)nOCCmF2m+1, with m = 1,2,3,4 or 5 have been synthesized. The influences of the PEO molar mass, the length of the perfluoroalkyl group (RF) and temperature on the cleavage of the ester bridge in aqueous solution and the effect of the hydrolysis process on the size of aggregates formed in water were studied. According to 1H and 19F NMR measurements the degree of functionalization obtained (up to 96 mol‐%) increases with the decrease in the length of the RF group. All of the derivatives showed ester cleavage in water in short time scales. The rates of hydrolysis of the ester bridge in aqueous solution were determined from pH‐measurements. It was verified that the rate law for hydrolysis corresponds to a pseudo‐first order type. The hydrolysis kinetic constant k increased with a decrease in the length of the RF group ranging from 0.2 × 10−3 s−1 for the longest RF group (C5F11) up to 1.2 × 10−2 s−1 for the shortest RF group (CF3). The value of k depended almost exclusively on the length of the perfluoroalkyl chain and was independent of the length of the PEO backbone (1 000 or 2 000 g · mol−1), as long as no additional phenomenon such as phase separation was present. It was also found that the change in the value of k with temperature followed a non‐Arrhenius pattern and there was an evident relationship between the non‐linearity in the ln k vs. 1/T relation with increasing temperatures and the occurrence of a macroscopic phase separation of LCST type. Dynamic light scattering measurements showed the coexistence of unimers with associated species with apparent hydrodynamic radii (Rh) of approximately 20–45 nm for all samples in aqueous solutions. These species might correspond to aggregates of a few micelles. For some samples also larger aggregates were found with Rh in the 100–500 nm range, which might be attributed to clusters of micelles.
magnified image
Higher‐order harmonic transmission‐line RF coil design for MR applications
Authors: Zhang Xiaoliang , Zhu Xiao‐Hong , Chen Wei 
Published: April 2005

AbstractA novel concept based on the use of higher‐order harmonic resonances in a transmission‐line resonator is introduced for the design of high‐frequency RF coils at high and ultrahigh fields, where conventional RF coil designs present difficulties and limitations. To demonstrate this concept, we successfully designed and fabricated a 400‐MHz RF coil for rat imaging using a second‐harmonic resonant microstrip transmission line. This coil has a high Q‐factor, reduces coil–cable interactions without the use of a matching balun, and has a broad range for tuning the coil's resonant frequency at the loaded condition. This work demonstrates that the use of higher‐order harmonics in a transmission‐line resonator provides an alternative, efficient approach to the design of large and high‐frequency RF coils. Magn Reson Med 53:1234–1239, 2005. © 2005 Wiley‐Liss, Inc.
Confidence mapping in diffusion tensor magnetic resonance imaging tractography using a bootstrap approach
Authors: Jones Derek K. , Pierpaoli Carlo 
Published: April 2005

AbstractThe bootstrap technique is an extremely powerful nonparametric statistical procedure for determining the uncertainty in a given statistic. However, its use in diffusion tensor MRI tractography remains virtually unexplored. This work shows how the bootstrap can be used to assign confidence to results obtained with deterministic tracking algorithms. By invoking the concept of a “tract‐propagator,” it also underlines the important effect of local fiber architecture or architectural milieu on tracking reproducibility. Finally, the practical advantages and limitations of the technique are discussed. Not only does the bootstrap allow any deterministic tractography algorithm to be used in a probabilistic fashion, but also its model‐free inclusion of all sources of variability (including those that cannot be modeled) means that it provides the most realistic approach to probabilistic tractography. Magn Reson Med 53:1143–1149, 2005. Published 2005 Wiley‐Liss, Inc.
A nonoverlapping domain decomposition method for variational inequalities derived from free boundary problems
Authors: Jiang Bin , Bruch John C. , Sloss James M. 
Published: April 2005

AbstractThe article proposes a nonoverlapping domain decomposition method for variational inequalities derived from free boundary problems. The free boundary value problem is broken up into two problems on nonoverlapping regions. In one region the problem is treated as a partial differential equation, while in the second region that contains the free boundary part, a variational inequality is considered. By solving these two related problems successively, we have shown that the successive solutions converge to the solution of the original problem. Application to a free surface seepage problem is given. © 2005 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2006
Steric and electronic substituent effects in hydrolysis and aminolysis of 4‐alkyl‐4‐methyl‐2‐aryl‐4,5‐dihydro‐1,3‐oxazol‐5‐ones
Authors: Sedlák Miloš , Keder Roman , Skála Pavel , Hanusek Jiří 
Published: April 2005

AbstractThe kinetics and mechanism of the acid‐catalysed hydrolysis of substituted 4‐alkyl‐4‐methyl‐2‐aryl‐4,5‐dihydro‐1,3‐oxazol‐5‐ones to the corresponding 2‐alkyl‐2‐benzoylaminopropanoic acids were studied. The Taft correlation of rate constants of the acid‐catalysed hydrolysis with alkyl substitution at the 4‐position of the 1,3‐oxazol‐5‐one ring is non‐linear. In the Hammett correlation, the value of ρ decreases with increasing steric demand of the alkyl substituent. With the 4‐isopropyl and tert‐butyl derivatives, ρ = − 0.63 and − 0.32, respectively. The protonated 4‐isopropyl and tert‐butyl derivatives undergo nucleophilic attack by water at the carbonyl carbon atom at the 5‐position of the 1,3‐oxazol‐5‐one ring to the extents of ca 70% and 60%, respectively. Another reaction path consists in nucleophilic attack by water at the 2‐position of the 1,3‐oxazol‐5‐one ring. The reaction kinetics of aminolyses of substituted 4‐isopropyl‐4‐methyl‐2‐phenyl‐1,3‐oxazol‐5(4H)‐ones (1a, 1b, 1f) giving substituted N‐{1,2‐dimethyl‐1‐[(propylamino)carbonyl]‐propyl}benzamides (3a, 3b, 3f, 4a) was studied in aqueous propylamine buffers. In the case of the aminolysis of 1a and 1b with propylamine, the rate‐limiting step consists in the decomposition of the intermediate In± catalysed by both the acidic and the basic buffer components. The base‐catalysed route is four times faster in both cases. In the case of the aminolysis of 1f with propylamine and that of 1a with ethylenediamine, the rate‐limiting step is the formation of the intermediate In±, the subsequent reaction step being accelerated by substitution and/or intramolecular catalysis. Copyright © 2005 John Wiley & Sons, Ltd.