bluuebunny/crossref_metadata_2025 huggingface dataset:
Back to the Coordination Modes of the Thiosemicarbazonate Chain: New Insights from Diorganolead(IV) and Lead(II) Derivatives of Isatin‐3‐thiosemicarbazone
Authors: Casas José S. , Casanova Noelia , García‐Tasende María S. , Sánchez Agustín , Sordo José , Touceda Ángeles , Vázquez Saulo
Published: September 2010

The syntheses and characterizations of the new heteroleptic complexes [PbPh2(OAc)(N2‐L1)]·MeOH·EtOH, [PbPh2(OAc)(N3‐L2)]·H2O, [Pb(OAc)(N2‐L1)], [Pb(OAc)(N3‐L1)]·3H2O and [Pb(OAc)(N2‐L2)] {HL1 = isatin‐3‐thiosemicarbazone, HL2 = isatin‐3‐(N1‐methylthiosemicarbazone); N2‐Lx = thiosemicarbazonate bound through O,S and the hydrazinic [N(2)] nitrogen atom; N3‐Lx = thiosemicarbazonate bound through the O,S and the iminic [N(3)] nitrogen atom} are described. The single‐crystal X‐ray structures of HL2, [PbPh2(OAc)(N2‐L1)]·MeOH·EtOH, [PbPh2(OAc)(N3‐L2)]·H2O, [Pb(OAc)(N2‐L1)] and [Pb(OAc)(N3‐L1)]·3H2O have been solved. The organometallic compounds [PbPh2(OAc)(N2‐L1)]·MeOH·EtOH and [PbPh2(OAc)(N3‐L2)]·H2O have a roughly similar distorted bipyramidal pentagonal stereochemistry, with apical phenyl groups and both the O,Nx,S‐coordinated Lx– and the anisobidentate AcO– ligands in the equatorial plane. In [PbPh2(OAc)(N2‐L1)]·MeOH·EtOH, the (N2‐L1)– ligand forms a four‐ and a six‐membered chelate ring with the metal, whereas in PbPh2(OAc)(N3‐L2)]·H2O the two chelate rings formed by (N3‐L2)– are five‐membered. The PbII complexes, [Pb(OAc)(N2‐L1)] and [Pb(OAc)(N3‐L1)], which were isolated from the same solution, are linkage isomers. These compounds have a rather irregular stereochemistry that suggests the presence of a stereochemically active lone electron pair; in [Pb(OAc)(N2‐L1)] the (L1)– ligand is O,N2,S‐coordinated and in [Pb(OAc)(N3‐L1)] this ligand is O,N3,S‐coordinated. Analyses of all these systems in solution by 1H and 13C NMR spectroscopy showed that during synthesis the kinetically controlled O,N2,S isomer formed first due to the rigidity of the ligand. If the compound remains in solution, slow partial evolution to the O,N3,S isomer occurs. DFT calculations predict that [Pb(OAc)(N3‐L1)] is slightly more stable than [Pb(OAc)(N2‐L1)] both in the gas phase and in DMSO solution. The calculations also modelled structures for the two isomers close to those obtained by X‐ray diffraction studies.
Convergent Total Synthesis of Murisolin
Authors: Quinn Kevin J. , Islamaj Livio , Couvertier Shalise M. , Shanley Kathleen E. , Mackinson Brendan L.
Published: September 2010

A convergent total synthesis of the mono(tetrahydrofuran) annonaceous acetogenin murisolin, with a longest linear sequence of nine steps, is reported. Assembly of the complete carbon framework by cross metathesis and late‐stage tetrahydrofuran formation on the intact backbone are key elements of the synthesis.
Highly Efficient Direct Asymmetric Aldol Reactions Catalyzed by a Prolinethioamide Derivative in Aqueous Media
Authors: Wang Bing , Liu Xin‐wang , Liu Ling‐yan , Chang Wei‐xing , Li Jing
Published: September 2010

L‐Prolinethioamide derivative 1c, prepared from the readily available natural amino acids L‐proline and L‐valine, was studied for the direct asymmetric aldol reaction of acetone with various aromatic aldehydes at 0 °C or room temperature. A loading of only 0.1–0.2 mol‐% of derivative 1c was employed in this catalytic system, and excellent enantioselectivities and yields (up to 98 % yield, >99 % ee) could be achieved in aqueous media.
Capacitance Evolution of Electrochemical Capacitors with Tailored Nanoporous Electrodes in Pure and Dissolved Ionic Liquids
Authors: Mysyk R. , Ruiz V. , Raymundo‐Piñero E. , Santamaria R. , Béguin F.
Published: September 2010

A homologous series of ionic liquids (IL) with 1‐alkyl‐3‐methylimidazolium cations of different lengths of alkyl chain was used to study the effect of cation size on the capacitive response of two carbons with a tailored pore size distribution. The results reveal a clear ion‐sieving effect in pure ILs, while the effect is heavily mitigated for the same salts used in solution, most likely due to somewhat stronger geometrical flexibility of dissolved ions. For the electrode material showing the ion‐sieving effect in solution, the gravimetric capacitance values are higher than in pure ILs. The dissimilarity of capacitance values between pure and dissolved ILs with ion‐sieving carbons highlights their respective advantages and disadvantages in terms of energy density: whereas pure ILs can potentially provide a larger working voltage window, the corresponding dissolved salts can access smaller pores, mostly contributing to higher capacitance values.
Ag as an Alternative for Ni in Direct Hydrocarbon SOFC Anodes
Authors: Cantos‐Gómez A. , Ruiz‐Bustos R. , van Duijn J.
Published: September 2010

Ag has been shown to be a good metal for SOFC anode cermets using CO fuel. Here we have expanded on the work reported by testing Ag‐YSZ cermets against different hydrocarbon based fuel (H2 and CH4). This study shows that while Ag is a good current collector, it alone does not have the required catalytic activity for the direct oxidation of hydrocarbon based fuels needed to be used in SOFC anodes. As such an additional catalytic material (e.g. CeO2) needs to be present when using fuels other then CO.
Synthesis of new heterocyclic system of 4,5,7,8‐tetrahydroimidazo[1,2‐c][1,3]thiazolo [4,5‐e][1,3,2]diazaphosphinine starting from 2‐aroylamino‐3,3‐dichloroacrylonitrile
Authors: Kozachenko Alexander P. , Shablykin Oleg V. , Gakh Andrei A. , Rusanov Eduard B. , Brovarets Vladimir S.
Published: September 2010

Easily accessible 2‐aroylamino‐3,3‐dichloroacrylonitriles, when treated successively with ethylenediamine, phosphorus pentasulfide, water, and methyl and benzyl halides, furnish the corresponding derivatives of 4,5,7,8‐tetrahydroimidazo[1,2‐c][1,3]thiazolo[4,5‐e][1,3,2]diazaphosphinine, a novel‐fused heterocycle. The structure of the compounds obtained is unequivocally confirmed by the spectroscopic method and X‐ray diffraction analysis. © 2010 Wiley Periodicals, Inc. Heteroatom Chem 21:492–498, 2010; View this article online at wileyonlinelibrary.com. DOI 10.1002/hc.20638
Facile synthesis of glycerol carbonate from glycerol using selenium‐catalyzed carbonylation with carbon monoxide
Authors: Mizuno Takumi , Nakai Takeo , Mihara Masatoshi
Published: September 2010

The commercial production of glycerol has increased considerably for several years, because of its rising inevitable formation as a by‐product of biodiesel. For the effective utilization of glycerol, a new synthesis of glycerol carbonate (4‐hydroxymethyl‐2‐oxo‐1,3‐dioxolane) that is used as solvents and raw material of plastics from glycerol was explored. By combined the selenium‐catalyzed carbonylation of slightly excess of glycerol with carbon monoxide and potassium carbonate under 0.1 MPa at 20°C for 4 h in DMF with the oxidation of resulting selenocarbonate salt with molecular oxygen (0.1 MPa, 20 °C) for 2 h, glycerol carbonate was obtained in good yields (83–84%). However, sodium hydride to form sodium alkoxide in situ lowered the yield of glycerol carbonate. Use of triethylamine, 1‐methylpyrrolidine, and DBU as bases gave poor results. Furthermore, styrene carbonate was obtained in excellent yield (90%) under similar reaction conditions. The catalytic synthesis of glycerol carbonate was also brought about in the mixed gas atmosphere (carbon monoxide:oxygen = 3:1, 0.1 MPa, 20°C). Glycerol carbonate and styrene carbonate were obtained in reasonable yields (197% and 119%, based on selenium used). © 2010 Wiley Periodicals, Inc. Heteroatom Chem 21:541–545, 2010; View this article online at wileyonlinelibrary.com. DOI 10.1002/hc.20640
Delineating site‐specific irrigation management zones
Authors: Jiang Qiuxiang , Fu Qiang , Wang Zilong
Published: September 2010

Since spatial heterogeneity of soil physical properties has a significant influence on site‐specific irrigation management, field moisture capacity, saturated moisture content, wilting point and soil dry bulk density were used as the data source to derive irrigation management zones. The spatial heterogeneity and correlations of soil properties were firstly characterized using geostatistics and principal component analysis. Then, irrigation management zones were delineated by running management zone analysis software based on the fuzziness performance index and normalized classification entropy, which were used to determine the least number of subzones. Finally, the zoning of irrigation management was verified by performing a statistical analysis as a statistical control of the above classifications. The study site was divided into two subzones having distinct differences between them, indicating that the delineation of irrigation management zones was reasonable. In additional, a stratified sampling method was also adopted to calculate the optimal sampling size of the soil properties in each subzone. Saturated moisture content has the optimal sampling size of 12 and soil water capacity and wilting point have the least, with only 3. The delineation of irrigation management zones and optimal sampling size could provide data support and science‐based information for site‐specific irrigation management. Copyright © 2010 John Wiley & Sons, Ltd.
Retracted: Bone healing in critical‐size defects treated with new bioactive glass/calcium sulfate: A histologic and histometric study in rat calvaria
Authors: Nagata Maria J. H. , Furlaneto Flávia A. C. , Moretti Antonio J. , Bouquot Jerry E. , Ahn Chul W. , Messora Michel R. , Fucini Stephen E. , Garcia Valdir G. , Bosco Alvaro F.
Published: September 2010

This study analyzed histologically the influence of new spherical bioactive glass (NBG) particles with or without a calcium sulfate (CS) barrier on bone healing in surgically created critical‐size defects (CSD) in rat calvaria. A CSD was made in each calvarium of 60 rats, which were divided into three groups: C (control): the defect was filled with blood clot only; NBG: the defect was filled with NBG only; and NBG/CS: the defect was filled with NBG covered by CS barrier. Subgroups were euthanized at 4 or 12 weeks. Amounts of new bone and remnants of implanted materials were calculated as percentages of total area of the original defect. Data were statistically analyzed. In contrast to Group C, thickness throughout defects in Groups NBG and NBG/CS was similar to the original calvarium. At 4 weeks, Group C had significantly more bone formation than Group NBG/CS. No significant differences were found between Group NBG and either Group C or Group NBG/CS. At 12 weeks, Group C had significantly more bone formation than Group NBG or NBG/CS. NBG particles, used with or without a CS barrier, maintained volume and contour of area grafted in CSD. Presence of remaining NBG particles might have accounted for smaller amount of new bone in Groups NBG and NBG/CS at 12 weeks post‐operative. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2010.
Formation of bioceramic coatings containing hydroxyapatite on the titanium substrate by micro‐arc oxidation coupled with electrophoretic deposition
Authors: Bai Yu , Park Il Song , Park Hyeoung Ho , Bae Tae Sung , Lee Min Ho
Published: September 2010

Bioactive ceramic coatings on titanium substrates were prepared successfully by micro‐arc oxidation coupled with electrophoretic deposition (MAO and EPD) in NaOH electrolyte solution containing hydroxyapatite (HA) particles. The HA suspensions with various NaOH concentrations were prepared by ultrasonic dispersion. The microstructure, as well as the elemental and phase composition of the coatings was examined by scanning electron microscopy, energy dispersive spectrometry, and X‐ray diffraction. X‐ray diffraction showed that the coatings were composed mainly of rutile, Na2Ti6O13, and HA phases. The composition and surface morphologies are strongly dependent on the NaOH electrolyte concentration. The corrosion behavior of the coating layers in simulated body fluids was evaluated using a potentiodynamic polarization test. The corrosion resistance of the coated sample was increased compared with the untreated titanium sample. The in vitro bioactivity assessment showed that the MAO and EPD‐treated titanium substrate possesses higher apatite‐forming ability than the only MAO‐treated titanium substrate. In addition, the cell behavior was also examined using cell proliferation assay, cell morphology, and alkaline phosphatase activity. They obtained an agreement with the result of apatite‐forming ability. The results clearly show that combining the MAO and EPD techniques provides an optimal surface for cell differentiation and osseointegration. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2010.
Cytotoxic response of three cell lines exposed in vitro to dental endodontic sealers
Authors: Brackett Martha Goël , Messer Regina L. W. , Lockwood Petra E. , Bryan Thomas E. , Lewis Jill B. , Bouillaguet Serge , Wataha John C.
Published: September 2010

The in vitro cytotoxicity of five endodontic sealers was measured >8‐12 weeks using L929 mouse fibroblasts, osteoblastic cells (ROS) 17/2.8 rat osteoblasts, and MC3T3‐E1 mouse osteoblasts. Discs (n = 6) of AH‐plus Jet (AHP), two versions of Endo Rez (ER, ERx), Epiphany (EPH), and Pulp Canal Sealer (PCS) were prepared. The sealers and Teflon (Tf, negative control) were placed in direct contact with cells after immersion in phosphate‐buffered saline for 1‐12 wk. Cellular succinate dehydrogenase (SDH) activity was estimated using the MTT method (3‐(4,5‐Dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide, a yellow tetrazole), and activities were normalized to Teflon® controls. The cellular responses to the materials were compared using analysis of variance with Tukey posthoc analyses (α = 0.05). Initially, all sealers suppressed normalized SDH activity of L929 fibroblasts by >90%. After 12 weeks of immersion in saline, AHP exhibited the SDH activity above Tf (120%), followed by ERx (78%), ER (58%), PCS (38%), and EPH (28%), all statistically distinct (p < 0.05). In general, the three cell lines responded similarly to the sealers. However, AHP caused unique responses: ROS cells were significantly (p < 0.05) less sensitive initially, and AHP was severely cytotoxic to MC3T3 cells (<35% of Tf) through 8 weeks. The data suggest that with “aging” in saline, current endodontic sealers decrease in in vitro cytotoxicity at different rates. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2010.
Bioactive glass scaffold with similar structure and mechanical properties of cancellous bone
Authors: Xia Wei , Chang Jiang
Published: September 2010

Natural bone is an amazing material because of its structure and mechanics. It is a challenge to find a bone substituted material mimicking natural bone intended to suffice for the need for bone repair and regeneration. In this study, a biomorphic material with similar structure and mechanical properties of cancellous bone has been fabricated by using demineralized cancellous bone as a template. Well‐oriented particles in the pore walls could be observed clearly. The compressive strength of this scaffold was up to about 4.9±0.2MPa, close to the lower limit of the natural bone and 30 times of bioactive glass scaffolds, even though the porosity was up to 90%. This kind of bioactive glass composite scaffolds presented high resistance to deformation and showed an excellent shape restoration property. It is very close to a natural cancellous bone with a similar macro‐ and micro‐structure and force‐extension behavior. These results suggested this material would have a good potential in bone tissue engineering. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2010.
Molecular dynamics simulations of aqueous ions at the liquid–vapor interface accelerated using graphics processors
Authors: Bauer Brad A. , Davis Joseph E. , Taufer Michela , Patel Sandeep
Published: September 2010

Molecular dynamics (MD) simulations are a vital tool in chemical research, as they are able to provide an atomistic view of chemical systems and processes that is not obtainable through experiment. However, large‐scale MD simulations require access to multicore clusters or supercomputers that are not always available to all researchers. Recently, scientists have returned to exploring the power of graphics processing units (GPUs) for various applications, such as MD, enabled by the recent advances in hardware and integrated programming interfaces such as NVIDIA's CUDA platform. One area of particular interest within the context of chemical applications is that of aqueous interfaces, the salt solutions of which have found application as model systems for studying atmospheric process as well as physical behaviors such as the Hoffmeister effect. Here, we present results of GPU‐accelerated simulations of the liquid–vapor interface of aqueous sodium iodide solutions. Analysis of various properties, such as density and surface tension, demonstrates that our model is consistent with previous studies of similar systems. In particular, we find that the current combination of water and ion force fields coupled with the ability to simulate surfaces of differing area enabled by GPU hardware is able to reproduce the experimental trend of increasing salt solution surface tension relative to pure water. In terms of performance, our GPU implementation performs equivalent to CHARMM running on 21 CPUs. Finally, we address possible issues with the accuracy of MD simulaions caused by nonstandard single‐precision arithmetic implemented on current GPUs. © 2010 Wiley Periodicals, Inc. J Comput Chem, 2011
Morphology and microanatomy of harbor porpoise (Phocoena phocoena) dorsal fin tubercles
Authors: Ginter Carly C. , Böttger S. Anne , Fish Frank E.
Published: September 2010

The unique pattern of small tubercles on the leading edge of the dorsal fins of harbor porpoises (Phocoena phocoena) has been widely noted in the literature, though their structure or function has never been conclusively identified. We examined external morphology and microanatomy of the tubercles for further understanding of the nature of the tubercles. Measurements were taken of height and peak‐to‐peak distance of the tubercles using scaled photographs. Mean tubercle height was standardized as a percentage of the dorsal fin height and ranged from 0.63 to 0.87%. Mean peak‐to‐peak distance ranged from 4.2 ± 2.0 to 5.6 ± 2.0 mm. The microstructure analysis of the dorsal fin leading edge, trailing edge and tubercles revealed an epidermal thickness of 0.7–2.7 mm with the thickest epidermis at the tubercular apex. The epidermis contained three distinct strata (=layers), including the stratum corneum, spinosum, and basale. The stratum corneum was significantly thickened in tubercles, over four times thicker than in the leading or trailing edge of the fin. The stratum spinosum, composed of lipokeratinocytes and lamellar oil bodies, was significantly thinner in the trailing edge than in the other two sites. There was no significant difference in the stratum basale among the three sites. Volume fraction of lipokeratinocytes was significantly higher at the sides of the leading edge and the apex of the tubercles, while volume fraction of lamellar oil bodies was significantly lower at the apex of the tubercles. Though the function of the tubercles is unknown, their position, hardened structure and increased epidermal stratum corneum suggest that they may have hydrodynamic importance. J. Morphol., 2011. © 2010 Wiley‐Liss, Inc.
Temperature interpolation based on local information: the example of France
Authors: Joly Daniel , Brossard Thierry , Cardot Hervé , Cavailhes Jean , Hilal Mohamed , Wavresky Pierre
Published: September 2010

Methods of interpolation, whether based on regressions or on kriging, are global methods in which all the available data for a given study area are used. But the quality of results is affected when the study area is spatially very heterogeneous. To overcome this difficulty, a method of local interpolation is proposed and tested here with temperature in France. Starting from a set of weather stations spread across the country and digitized as 250 m‐sided cells, the method consists in modelling local spatial variations in temperature by considering each point of the grid and the n weather stations that are its nearest neighbours. The procedure entails a series of steps: recognition of the n stations closest to the cell to be evaluated and subdivision of the study area into polygons defined by a neighbourhood rule, elaboration of a local model by multiple regression for each polygon, and application of the parameter estimate from the regression to obtain a predicted value of temperature at each point of the polygon under consideration.

These results are compared with results from three global interpolation methods: (1) regression, (2) ordinary kriging, and (3) regression with kriging of residuals. We then develop the original results from local interpolation such as mapping of the coefficients of determination and of the parameter estimate related to altitude and to distance to the sea. These developments highlight the processes that dictate the spatial variation of climate. Copyright © 2010 Royal Meteorological Society
Moisture and heat budgets associated with the South American monsoon system and the Atlantic ITCZ
Authors: Garcia Sâmia R. , Kayano Mary T.
Published: September 2010

Moisture and heat budgets in selected areas of the South American monsoon system (SAMS) and the equatorial Atlantic are examined for the 1979–2006 period. These areas are the Central Amazon (CAM), western Central Brazil (WCB), South Atlantic convergence zone (SACZ) and the Atlantic inter‐tropical convergence zone (ITCZ). The moisture and heat budget terms are calculated using daily reanalyzed data, and filtered for the 0.4–1.2 year scale. Analyses are based on the correlation maps between these terms and the expansion coefficient of the SAMS mode, previously identified. The vertical structures of the moisture and heat budget terms are discussed and allow us to examine the thermodynamic reasoning of the SAMS relationship with the Atlantic ITCZ. Important differences in the moisture and heat budgets have been found among the analyzed areas. Except for the horizontal advection of q and T, indications of a wet and dry season appear in the anomalies of other terms 4 pentads earlier in the WCB than in the CAM. The SAMS and the ITCZ relate to each other through the moisture and heat budgets. A time lag of approximately 8 pentads is noted for the moisture sink (source) and heat source (sink) between the CAM and ITCZ regions during the wet (dry) season of both regions. Indeed, the largest negative (positive) values of the residue term and the largest positive (negative) values of the diabatic term occur at pentad 12 (44) for the CAM and at pentad 20 (52) for the ITCZ. The results here provide observational support to the relationship between the SAMS and the Atlantic ITCZ. Copyright © 2010 Royal Meteorological Society
Attribution of the river flow growth in the Plata Basin
Authors: Doyle Moira E. , Barros Vicente R.
Published: September 2010

A regression approach was used to quantitatively estimate the attribution of the notable growth in the river flows of the Plata Basin during 1960–1999. The study was conducted in seven large basins that account for most of the Plata River discharge. Annual rainfall integrated over each basin and annual river flows at their closing points were used for the analysis. The contribution of rainfall changes during each of the three phases of El Niño‐Southern Oscillation to total rainfall change in these basins was also calculated.

The two main drivers for the generalized growth of the river flows were the increased precipitation and the decreased evaporation attributable to land use change, including deforestation of natural forest and crop switch from sugarcane and coffee trees to soybean. Other evaporation changes played a minor role. There was a north‐south gradient in the respective importance of each driver, with land use change having greater weight in the northern basins and the precipitation increase in the southern ones. Thus, in the northern part of the Upper Paraná Basin, despite the negative trend in precipitation there was a strong augment of the river flow caused by land use change. The contribution to the positive trend of the stream flows in the middle of the Plata Basin came from both land use change and increased precipitation. Finally, in the south, the Uruguay River flow change was basically due to the precipitation trend that was not only observed during the El Niño phase, but also during the Neutral phase.

Only in the Middle Paraguay Basin was the shift to more frequent and intense El Niño events that took place in the 1970s an important factor in the contribution of precipitation to streamflow trends. Copyright © 2010 Royal Meteorological Society
The influence of a film on destination image and the desire to travel: a cross‐cultural comparison
Authors: Hudson Simon , Wang Youcheng , Gil Sergio Moreno
Published: September 2010

The objective of this study was to measure the immediate impacts of a film on the perceptions of viewers from different countries. The film chosen for this experiment was the Motorcycle Diaries in which South America was featured prominently in the film. Using established scales from the tourism and marketing literature, viewers from the USA, Canada and Spain were surveyed before and after seeing the film, and results showed that the film did change the viewers' perceptions of South America. After watching the film, a large percentage of the respondents expressed a desire to visit the countries seen in the film, with Canadians showing a significantly higher desire to visit South America than the US and Spanish participants. Those who were motivated to travel by the film were especially influenced by the scenery, landscape and the cultural attractions of the destination as depicted in the movie. Copyright © 2010 John Wiley & Sons, Ltd.
Manipulated Electrospun PVA Nanofibers with Inexpensive Salts
Authors: Ding Wei , Wei Suying , Zhu Jiahua , Chen Xuelong , Rutman Dan , Guo Zhanhu
Published: September 2010

PVA nanofibers have been successfully prepared via an electrospinning process by optimizing the electrospinning operational parameters including applied voltage, polymer concentration, feed rate, and working distance. Inexpensive NaCl and Fe(NO3)3 are found to reduce the fiber size drastically (minimum of 157 and 169 nm, respectively) even at a low loading. The thermal stability is investigated by both thermogravimetric analysis and differential scanning calorimetry. Fourier transform infrared spectroscopy is utilized to characterize the functionality of the fibers and to investigate the interaction between PVA and inorganic additions. Glass transition and melting temperatures of the PVA fibers have slight change with the increase of the salt loading.

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Geometrical embeddings of distributions into algebras of generalized functions
Authors: Dave Shantanu
Published: September 2010

We use spectral theory to produce embeddings of distributions into algebras of generalized functions on a closed (compact without boundary) Riemannian manifold. These embeddings are invariant under isometries and preserve the singularity structure of the distributions (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A refinement of Vietoris' inequality for sine polynomials
Authors: Alzer Horst , Koumandos Stamatis , Lamprecht Martin
Published: September 2010

Let

equation image

where

equation image

In 1958, Vietoris proved that σn (x) is positive for all n ≥ 1 and x ∈ (0, π). We establish the following refinement. The inequalities

equation image

hold for all natural numbers n and real numbers n ≥ 1 and x ∈ (0, π) if and only if

equation image
Absence of collapse in a parabolic chemotaxis system with signal‐dependent sensitivity
Authors: Winkler Michael
Published: September 2010

We consider the chemotaxis system

equation image

under homogeneous Neumann boundary conditions in a smooth bounded domain Ω ⊂ ℝn. The chemotactic sensitivity function is assumed to generalize the prototype

equation image

It is proved that no chemotactic collapse occurs in the sense that for any choice of nonnegative initial data (with some r > n), the corresponding initial‐boundary value problem possesses a unique global solution that is uniformly bounded (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Parabolic quasi‐concavity for solutions to parabolic problems in convex rings
Authors: Ishige Kazuhiro , Salani Paolo
Published: September 2010

We investigate some geometric properties of level sets of the solutions of parabolic problems in convex rings. We introduce the notion of parabolic quasi‐concavity, which involves time and space jointly and is a stronger property than the spatial quasi‐concavity, and study the convexity of superlevel sets of the solutions (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Monte Carlo Simulation Studies of the Size and Shape of Linear and Star‐Branched Copolymers Embedded in a Tetrahedral Lattice
Authors: Zifferer Gerhard , Eggerstorfer Daniel
Published: September 2010

Characteristic properties of linear (F = 2) and star‐branched copolymers withF = 3 to 12 arms in common good, common theta and in selective solvents are summarized. Based on ensembles of chains or stars with chain lengths up to ≈50 000 segments, exponents of scaling laws of mean square dimensions of the whole star and of individual blocks and arms may be reduced to five cases. Several ratios which compare stars to linear chains (so‐called gfactors) and shape‐parameters in the limit of infinite chain lengths are deduced from the prefactors of scaling laws and by proper extrapolation, respectively. Shape parameters give evidence for some orientation effects which in addition are directly demonstrated.

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Assessment of multiexponential diffusion features as MRI cancer therapy response metrics
Authors: Hoff Benjamin A. , Chenevert Thomas L. , Bhojani Mahaveer S. , Kwee Thomas C. , Rehemtulla Alnawaz , Le Bihan Denis , Ross Brian D. , Galbán Craig J.
Published: September 2010

The aim of this study was to empirically test the effect of chemotherapy‐induced tissue changes in a glioma model as measured by several diffusion indices calculated from nonmonoexponential formalisms over a wide range of b‐values. We also compared these results to the conventional two‐point apparent diffusion coefficient calculation using nominal b‐values. Diffusion‐weighted imaging was performed over an extended range of b‐values (120–4000 sec/mm2) on intracerebral rat 9L gliomas before and after a single dose of 1,3‐bis(2‐chloroethyl)‐1‐nitrosourea. Diffusion indices from three formalisms of diffusion‐weighted signal decay [(a) two‐point analytical calculation using either low or high b‐values, (b) a stretched exponential formalism, and (c) a biexponential fit] were tested for responsiveness to therapy‐induced differences between control and treated groups. Diffusion indices sensitive to “fast diffusion” produced the largest response to treatment, which resulted in significant differences between groups. These trends were not observed for “slow diffusion” indices. Although the highest rate of response was observed from the biexponential formalism, this was not found to be significantly different from the conventional monoexponential apparent diffusion coefficient method. In conclusion, parameters from the more complicated nonmonoexponential formalisms did not provide additional sensitivity to treatment response in this glioma model beyond that observed from the two‐point conventional monoexponential apparent diffusion coefficient method. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.
Compressed sensing for chemical shift‐based water–fat separation
Authors: Doneva Mariya , Börnert Peter , Eggers Holger , Mertins Alfred , Pauly John , Lustig Michael
Published: September 2010

Multi echo chemical shift‐based water–fat separation methods allow for uniform fat suppression in the presence of main field inhomogeneities. However, these methods require additional scan time for chemical shift encoding. This work presents a method for water–fat separation from undersampled data (CS‐WF), which combines compressed sensing and chemical shift‐based water–fat separation. Undersampling was applied in the k‐space and in the chemical shift encoding dimension to reduce the total scanning time. The method can reconstruct high quality water and fat images in 2D and 3D applications from undersampled data. As an extension, multipeak fat spectral models were incorporated into the CS‐WF reconstruction to improve the water–fat separation quality. In 3D MRI, reduction factors of above three can be achieved, thus fully compensating the additional time needed in three‐echo water–fat imaging. The method is demonstrated on knee and abdominal in vivo data. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.
Highly accelerated contrast‐enhanced MR angiography: Improved reconstruction accuracy and reduced noise amplification with complex subtraction
Authors: Koktzoglou Ioannis , Sheehan John J. , Dunkle Eugene E. , Breuer Felix A. , Edelman Robert R.
Published: September 2010

Contrast‐enhanced magnetic resonance angiography is routinely performed using parallel imaging to best capture the first pass of contrast material through the target vasculature, followed by digital subtraction to suppress the appearance of unwanted signal from background tissue. Both processes, however, amplify noise and can produce uninterpretable images when large acceleration factors are used. Using a phantom study of contrast‐enhanced magnetic resonance angiography, we show that complex subtraction processing prior to partially parallel reconstruction improves reconstruction accuracy relative to magnitude subtraction processing for reduction factors as large as 12. Time‐resolved contrast‐enhanced magnetic resonance angiographic data obtainedwith complex subtraction in volunteers supported the results of the phantom study and when compared with magnitude subtraction processing demonstrated reduced geometry factors as well as improved image quality at large reduction factors. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.
Dynamic contrast‐enhanced MRI of neuroendocrine hepatic metastases: A feasibility study using a dual‐input two‐compartment model
Authors: Koh T. S. , Thng C. H. , Hartono S. , Kwek J. W. , Khoo J. B. K. , Miyazaki K. , Collins D. J. , Orton M. R. , Leach M. O. , Lewington V. , Koh D.‐M.
Published: September 2010

Neuroendocrine hepatic metastases exhibit various contrast uptake enhancement patterns in dynamic contrast‐enhanced MRI. Using a dual‐input two‐compartment distributed parameter model, we analyzed the dynamic contrast‐enhanced MRI datasets of seven patient study cases with the aim to relate the tumor contrast uptake patterns to parameters of tumor microvasculature. Simulation studies were also performed to provide further insights into the effects of individual microcirculatory parameter on the tumor concentration‐time curves. Although the tumor contrast uptake patterns can be influenced by many parameters, initial results indicate that hepatic blood flow and the ratio of fractional vascular volume to fractional interstitial volume may potentially distinguish between the patterns of neuroendocrine hepatic metastases. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.
Mapping of redox status in a brain‐disease mouse model by three‐dimensional EPR imaging
Authors: Fujii Hirotada , Sato‐Akaba Hideo , Kawanishi Katsuya , Hirata Hiroshi
Published: September 2010

Electron paramagnetic resonance imaging using nitroxides is a powerful method for visualizing the redox status modulated by oxidative stress in vivo. Typically, however, data acquisition times have been too slow to obtain a sufficient number of projections for three‐dimensional images, when using continuous wave‐electron paramagnetic resonance imager in small rodents, using nitroxides with comparatively short T2 and a half‐life values. Because of improvements in imagers that enable rapid data‐acquisition, the feasibility of three‐dimensional electron paramagnetic resonance imaging with good quality in mice was tested with nitroxides. Three‐dimensional images of mice were obtained at an interval of 15 sec under field scanning of 0.3 sec and with 46 projections in the case of strong electron paramagnetic resonance signals. Three‐dimensional electron paramagnetic resonance images of a blood brain barrier‐permeable nitroxide, 3‐hydroxymethyl‐2,2,5,5‐tetramethylpyrrolidine‐1‐oxyl, in the mouse head clearly showed that 3‐hydroxymethyl‐2,2,5,5‐tetramethylpyrrolidine‐1‐oxyl was distributed within brain tissues, and this was confirmed by MRI observations. Based on the pharmacokinetics of nitroxides in mice, half‐life mapping was demonstrated in an ischemia‐reperfusion model mouse brain. Inhomogeneous half‐lives were clearly mapped pixel‐by‐pixel in mouse head under oxidative stress by the improved continuous wave‐electron paramagnetic resonance imager noninvasively. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.
Influence of brain tumors on the MR spectra of healthy brain tissue
Authors: Busch M. , Liebenrodt K. , Gottfried S. , Weiland E. , Vollmann W. , Mateiescu S. , Winter S. , Lange S. , Sahinbas H. , Baier J. , van Leeuwen P. , Grönemeyer D.
Published: September 2010

The neurochemical environment of nontumorous white matter tissue was investigated in 135 single voxel spectra of “healthy” white matter regions of 43 tumor patients and 129 spectra of 52 healthy subjects. Spectra were acquired with short TE and TR values. With the data of tumor patients, it was examined whether differences were caused by the tumor itself or aggressive tumor therapies as confounding factors. Comparing the spectra of both classes, an excellent differentiation was possible based on the metabolite peak of N‐acetylaspartate (P ≈ 0) and myoinositol (P < 0.03). The area under curve of the receiver operating characteristic was calculated as 0.86 and 0.62, respectively. With linear discriminant analysis using combinations of integrals, a prediction was possible, whether a spectrum belonged to the patient or the healthy subject class with an overall accuracy above 80%. The confounding factors could be ruled out as source of the differences. The results show strong evidence for an influence of malignant growth on the biochemical environment of nontumorous white matter tissue. Because of the T1 weighting, the measured differences between both classes were most likely concentration changes interfered by T1 effects. The underlying processes will be subject of future studies. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.
Post‐processing correction of magnetization transfer effects in FENSI perfusion MRI data
Authors: Reynaud Olivier , Ciobanu Luisa
Published: September 2010

Magnetization transfer effects induced by repetitive saturation pulses employed in flow enhancement of signal intensity imaging sequences currently prevent quantitative, in vivo, cerebral perfusion studies. This study investigates the magnitude of these effects and introduces a post‐processing correction protocol. The study shows that the magnetization transfer effect is consistent across individuals, which enables the derivation of a correction factor to be applied in post‐acquisition. Our results, obtained for cerebral flux in white and gray matter in rodent brains, are in agreement with cerebral blood flow measurements previously reported in the literature. Magn Reson Med, 2011. © 2010 Wiley‐Liss, Inc.
Measuring perfusion and bioenergetics simultaneously in mouse skeletal muscle: a multiparametric functional‐NMR approach
Authors: Baligand C. , Wary C. , Ménard J. C. , Giacomini E. , Hogrel J.‐Y. , Carlier P. G.
Published: September 2010

A totally noninvasive set‐up was developed for comprehensive NMR evaluation of mouse skeletal muscle function in vivo. Dynamic pulsed arterial spin labeling‐NMRI perfusion and blood oxygenation level‐dependent (BOLD) signal measurements were interleaved with 31P NMRS to measure both vascular response and oxidative capacities during stimulated exercise and subsequent recovery. Force output was recorded with a dedicated ergometer. Twelve exercise bouts were performed. The perfusion, BOLD signal, pH and force–time integral were obtained from mouse legs for each exercise. All reached a steady state after the second exercise, justifying the pointwise summation of the last 10 exercises to compensate for the limited 31P signal. In this way, a high temporal resolution of 2.5 s was achieved to provide a time constant for phosphocreatine (PCr) recovery (τPCr). The higher signal‐to‐noise ratio improved the precision of τPCr measurement [coefficient of variation (CV) = 16.5% vs CV = 49.2% for a single exercise at a resolution of 30 s]. Inter‐animal summation confirmed that τPCr was stable at steady state, but shorter (89.3 ± 8.6 s) than after the first exercise (148 s, p < 0.05). This novel experimental approach provides an assessment of muscle vascular response simultaneously to energetic function in vivo. Its pertinence was illustrated by observing the establishment of a metabolic steady state. This comprehensive tool offers new perspectives for the study of muscle pathology in mice models. Copyright © 2010 John Wiley & Sons, Ltd.
A novel approach for anionic bulk polymerization of 1,3,5‐tris(trifluoropropylmethyl)cyclotrisiloxane
Authors: Gao Yajuan , Jiang Wei , Guan Yong , Yang Peng , Zheng Anna
Published: September 2010

Present work gave a new method for preparing polymethyl(3,3,3‐trifluoropropyl)siloxane (PMTFPS) in the mixing chamber of a torque rheometer using sodium silanolate as initiator, and ethyl acetate (EA) and dimethyl sulfoxide (DMSO) as promoters. The promoting effect of EA in the anionic bulk polymerization of 1,3,5‐tris(trifluoropropylmethyl) cyclotrisiloxane (F3) was investigated in comparison with DMSO, a common promoter. Results showed that EA exhibited an effective promoting effect as DMSO did. When the polymerization was carried out for 4.0 min at 120°C in the presence of 0.30 mol L−1 EA, the maximum of number average molecular weight (Mn = 2.45 × 105 g mol−1) of PMTFPS was obtained with high yield (89.2 wt%). The back‐biting reactions during the polymerization were almost suppressed and less than 0.75 wt% cyclic by‐products were obtained by matrix‐assisted laser desorption ionization time‐of‐flight mass spectrometry (MALDI‐TOF‐MS) for EA promoter system. Investigations of differential scanning calorimetry and thermogravimetic analysis showed that PMTFPS could be used in a wide range of operational temperatures. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers
Manufacturing and testing of long basalt fiber reinforced thermoplastic matrix composites
Authors: Deák Tamás , Czigány Tibor , Maršálková Miroslava , Militký Jiří
Published: September 2010

In this work, long basalt fiber reinforced composites were investigated and compared with short basalt fiber reinforced compounds. The results show that long fiber reinforced thermoplastic composites are particularly advantageous in the respects of dynamic mechanical properties and injection molding shrinkage. The fiber orientation in long basalt fiber reinforced products fundamentally differs from short basalt fiber reinforced ones. This results in more isotropic molding shrinkage in case of long basalt fiber reinforced composites. The main advantage of the used long fiber thermoplastic technology is that the special long fiber reinforced pellet can be processed by most conventional injection molding machines. During extrusion compounding the fibers in the compound containing 30 wt% fibers are fragmented to an average length of 0.48 mm (typical of short fiber reinforced thermoplastic compounds), this length decreases further during injection molding to 0.20 mm. Contrarily using long fiber reinforced pellets and cautious injection molding parameters, an average fiber length of 1.8 mm can be achieved with a conventional injection molding machine, which increased the average length/diameter ratio from 14 to 130. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers
Influence of processing condition and HA content on the crystallization behavior of HA‐filled EVA biocomposite
Authors: Wang Yanying , Zhang Li , Zhou Song , Huang Di , Gao Shibo , Gong Mei , Li Yubao
Published: September 2010

Hydroxyapatite/ethylene‐vinyl acetate (HA/EVA) composites with a HA content of 30 and 50 wt% were prepared by injection molding. The crystallization behaviors of EVA under different injection pressure, annealing temperature, and HA content were investigated. Fourier transform infrared spectroscopy (FTIR), X‐ray diffraction (XRD), differential scanning calorimetry (DSC), and scanning electron microscope were used to evaluate the composites. The result of FTIR analysis infers the occurrence of hydrogen bonding between HA and EVA. XRD and DSC analyses show that the increasing injection pressure can accelerate the crystallization rate of EVA but it tends to decrease the crystallization degree slightly, which may be caused by the increase of EVA segmental activity and the loss of EVA crystallization order with the increase of pressure. The EVA crystallization degree can be improved by the annealing process. It is found that HA can induce more nucleation sites of EVA, but the crystallization degree of EVA decreases with the increase of HA content. The large content of HA acts to reduce the mobility of EVA crystallizable chain segments and inhibits the crystal growth of EVA. POLYM. ENG. SCI., 2011. © 2010 Society of Plastics Engineers
Structural determinants of tobacco vein mottling virus protease substrate specificity
Authors: Sun Ping , Austin Brian P. , Tözsér József , Waugh David S.
Published: September 2010

Tobacco vein mottling virus (TVMV) is a member of the Potyviridae, one of the largest families of plant viruses. The TVMV genome is translated into a single large polyprotein that is subsequently processed by three virally encoded proteases. Seven of the nine cleavage events are carried out by the NIa protease. Its homolog from the tobacco etch virus (TEV) is a widely used reagent for the removal of affinity tags from recombinant proteins. Although TVMV protease is a close relative of TEV protease, they exhibit distinct sequence specificities. We report here the crystal structure of a catalytically inactive mutant TVMV protease (K65A/K67A/C151A) in complex with a canonical peptide substrate (Ac‐RETVRFQSD) at 1.7‐Å resolution. As observed in several crystal structures of TEV protease, the C‐terminus (∼20 residues) of TVMV protease is disordered. Unexpectedly, although deleting the disordered residues from TEV protease reduces its catalytic activity by ∼10‐fold, an analogous truncation mutant of TVMV protease is significantly more active. Comparison of the structures of TEV and TVMV protease in complex with their respective canonical substrate peptides reveals that the S3 and S4 pockets are mainly responsible for the differing substrate specificities. The structure of TVMV protease suggests that it is less tolerant of variation at the P1′ position than TEV protease. This conjecture was confirmed experimentally by determining kinetic parameters kcat and Km for a series of oligopeptide substrates. Also, as predicted by the cocrystal structure, we confirm that substitutions in the P6 position are more readily tolerated by TVMV than TEV protease.