bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mechanical properties of femoral cortical bone following cemented hip replacement
Authors: Ni G.X. , Lu W.W. , Chiu P.K.Y. , Wang Y. , Li Z.Y. , Zhang Y.G. , Xu B. , Deng L.F. , Luk K.D.K. 
Published: May 2007

AbstractFemoral bone remodeling following total hip replacement is a big concern and has never been examined mechanically. In this study, six goats underwent unilateral cemented hip hemiarthroplasty with polymethyl methacrylate (PMMA) bone cement. Nine months later animals were sacrificed, and the femoral cortical bone slices at different levels were analysed using microhardness testing and microcomputed tomography (micro‐CT) scanning. Implanted femurs were compared to contralateral nonimplanted femurs. Extensive bone remodeling was demonstrated at both the proximal and middle levels, but not at the distal level. Compared with the nonimplanted side, significant decreases were found in the implanted femur in cortical bone area, bone mineral density, and cortical bone hardness at the proximal level, as well as in bone mineral density and bone hardness at the middle level. However, no significant difference was observed in either variable for the distal level. In addition, similar proximal‐to‐distal gradient changes were revealed both in cortical bone microhardness and bone mineral density. From the mechanical point of view, the results of the present study suggested that stress shielding is an important mechanical factor associated with bone adaptation following total hip replacement. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 25:1408–1414, 2007
State‐local relations: The state mandate irritant
Authors: Zimmerman Joseph F. 
Published: May 2007

AbstractThe so‐called Dillon's Rule is the source of conflicts in state‐local relations in New York and other states. From the point of view of local officials one of the chief irritants of the control system is the “state mandate” which in many cases may more properly be called a “state restraint.” It may be statutory, constitutional or administrative. Not all mandates mean additional costs.
Controlled/living free‐radical copolymerization of 4‐(azidocarbonyl) phenyl methacrylate with methyl acrylate under 60Co γ‐ray irradiation
Authors: Zheng Haiting , Hua Daoben , Bai Ruke , Hu Keliang , An Lijia , Pan Caiyuan 
Published: May 2007

AbstractA new vinyl acyl azide monomer, 4‐(azidocarbonyl) phenyl methacrylate, has been synthesized and characterized by NMR and FTIR spectroscopy. The thermal stability of the new monomer has been investigated with FTIR and thermal gravimetry/differential thermal analysis (TG/DTA), and the monomer has been demonstrated to be stable below 50 °C in the solid state. The copolymerizations of the new monomer with methyl acrylate have been carried out at room temperature under 60Co γ‐ray irradiation in the presence of benzyl 1H‐imidazole‐1‐carbodithioate. The results show that the polymerizations bear all the characteristics of controlled/living free‐radical polymerizations, such as the molecular weight increasing linearly with the monomer conversion, the molecular weight distribution being narrow (<1.20), and a linear relationship existing between ln([M]0/[M]) and the polymerization time. The data from 1H NMR and FTIR confirm that no change in the acyl azide groups has occurred in the polymerization process and that acyl azide copolymers have been obtained. The thermal stability of the polymers has also been investigated with TG/DTA and FTIR. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 2609–2616, 2007
Synthesis of poly(acrylic acid)‐block‐poly(L‐valine) hybrid through combined atom transfer radical polymerization, click chemistry, and nickel‐catalyzed ring opening polymerization methods
Authors: Sinaga A. , Ravi P. , Hatton T. A. , Tam K. C. 
Published: May 2007

AbstractA new hybrid amphiphilic system between a polyacrylic acid (PAA) synthetic segment, and a hydrophobic β‐sheet forming peptide segment, poly(L‐valine) (PLVAL) was synthesized using a combination of Atom Transfer Radical Polymerization, Click Chemistry, and Nickel catalyzed ring opening of L‐valine N‐carboxyanhydride. This is the first reported use of Click Chemistry as an intermediary step for the ω‐amino functionalization of polymers to obtain macroinitiators that are free from deactivating or interfering molecules to be used in subsequent Ni‐catalyzed ring opening reaction. The efficiency of the end‐group functionalization in the macroinitiator is about 90%. Three different PAA‐b‐PLVAL hybrid copolymers with molecular weight range of 8000–15,000 and Mw/Mn <1.3 had been prepared by varying the monomer to macroinitiator ratio. In addition, the highest achievable molecular weight in the copolymerization was found to be limited by the solubility of the growing chains. This combined synthetic approach can potentially be extended for the synthesis of a multitude of other peptide hybrid systems, and hence will be of interest in the preparation of peptide hybrid systems. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 2646–2656, 2007
Catalyzed chain growth of polyethylene on magnesium for the synthesis of macroalkoxyamines: Application to the production of block copolymers using controlled radical polymerization
Authors: Godoy Lopez Ricardo , Boisson Christophe , D'Agosto Franck , Spitz Roger , Boisson Fernande , Gigmes Didier , Bertin Denis 
Published: May 2007

AbstractA synthetic method for the production of polyethylene (PE) chains carrying alkoxyamine end‐group has been proposed first by successfully reacting the well‐known 2,2,6,6‐tetramethylpiperidine‐N‐oxyl (TEMPO) and N‐(2‐methyl‐2‐propyl)‐N‐(1‐diethylphosphono‐2,2‐dimethylpropyl)‐N‐oxyl (commonly called SG1) stable radicals with dipolyethylenylmagnesium compounds to give PE‐TEMPO and PE‐SG1. Since the homolytic cleavage of these two macroalkoxyamines for the production of block copolymers using controlled radical polymerization would require temperatures higher than 160 °C, two original new nitroxides (4‐[(2,2‐dimethyl‐4‐(N‐tert‐Butyl‐N‐(1‐diethoxyphosphoryl‐2,2‐dimethylpropyl)aminoxy)‐4‐n‐butoxycarbonyl)butanoyloxyl]‐2,2,6,6‐tetramethylpiperidinyl‐1‐oxy, DD1) and 4‐[(2,2‐dimethyl‐4‐(N‐tert‐Butyl‐N‐(1‐diethoxyphosphoryl‐2,2‐dimethylpropyl)aminoxy)‐4‐phenyl) butanoyloxyl]‐2,2,6,6‐tetramethylpiperidinyl‐1‐oxy, DD2) containing a TEMPO moiety and incorporating an SG1‐based alkoxyamine (cleavage temperature: 60 °C) were then synthesized. NMR analyses showed that the resulting PE‐DD1 and PE‐DD2 were obtained using this functionalization strategy though with low to moderate yields (from 17% to 40%). PE‐DD2 (40% functionalization) was used under controlled radical polymerization conditions of n‐butyl acrylate. SEC analyses together with 1H NMR analysis showed that a poly(ethylene‐b‐n‐butyl acrylate) block copolymer was produced and that the polymerization proceeded under control. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 2705–2718, 2007
Stochastic multi‐player pursuit–evasion differential games
Authors: Li Dongxu , Cruz Jose B. , Schumacher Corey J. 
Published: May 2007

AbstractAutonomous aerial vehicles play an important role in military applications such as in search, surveillance and reconnaissance. Multi‐player stochastic pursuit–evasion (PE) differential game is a natural model for such operations involving intelligent moving targets with uncertainties. In this paper, some fundamental issues of stochastic PE games are addressed. We first model a general stochastic multi‐player PE differential game with perfect state information. To avoid the difficulty of multiplicity of the players, we extend the iterative method for deterministic multi‐player PE games to the stochastic case. Starting from certain suboptimal solutions with an improving property, the optimization based on limited look‐ahead can be used for improvement. The process converges when this improvement is applied iteratively. Furthermore, we introduce a hierarchical approach that can determine a valid starting point of the iterative process. As a basis for multi‐player games, stochastic two‐player PE games are also addressed. We also briefly discuss the games with imperfect state information and propose a suboptimal approach from a practical point of view. Finally, we demonstrate the usefulness and the feasibility of the method through simulations. Copyright © 2007 John Wiley & Sons, Ltd.
Structural and electrochemical studies of annealed LiNiVO4 thin films
Authors: Reddy M. V. , Pecquenard B. , Vinatier P. , Levasseur A. 
Published: May 2007

AbstractWe prepared stoichiometric lithium nickel vanadate amorphous thin films by using r.f. magnetron sputtering under controlled oxygen partial pressure. The amorphous films were heated at various temperatures, 300–600 °C, for 8 h. The as‐deposited and annealed thin films were characterized by Rutherford backscattering spectroscopy, nuclear reaction analysis, Auger electron spectroscopy, X‐ray diffraction, scanning electron microscopy and atomic force microscopy. The electrochemical behavior of the various films was studied by the galvanostatic method. The cells were tested in a liquid electrolyte at room temperature, with lithium metal used as the counter and reference electrode. The best electrochemical storage value was obtained with the thin film annealed at 300 °C, which showed superior capacity and small capacity loss during cycling. Copyright © 2007 John Wiley & Sons, Ltd.
Molecular characterization of the PEX5 gene encoding peroxisomal targeting signal 1 receptor from the methylotrophic yeast Pichia methanolica
Authors: Ito Takashi , Fujimura Shuki , Matsufuji Yoshimi , Miyaji Tatsuro , Nakagawa Tomoyuki , Tomizuka Noboru 
Published: May 2007

AbstractIn this study, we describe the molecular characterization of the PEX5 gene encoding the peroxisomal targeting signal 1 (PTS1) receptor from the methylotrophic yeast Pichia methanolica. The P. methanolica PEX5 (PmPEX5) gene contains a open reading frame corresponding to a gene product of 646 amino acid residues, and its deduced amino acid sequence shows a high similarity to those of Pex5ps from other methylotrophic yeasts. Like other Pex5ps, the PmPex5p possesses seven repeats of the TPR motif in the C‐terminal region and three WXXXF/Y motifs. A strain with the disrupted PEX5 gene (pex5Δ) lost its ability to grow on peroxisome‐inducible carbon sources, methanol and oleate, but grew normally on glucose and glycerol. Disruption of PmPEX5 caused a drastic decrease in peroxisomal enzyme activities and mislocalization of GFP–PTS1 and some peroxisomal methanol‐metabolizing enzymes in the cytosol. Expression of the PmPEX5 gene was regulated by carbon sources, and it was strongly expressed by peroxisome‐inducible carbon sources, especially methanol. Taken together, these findings show that PmPex5p has an essential physiological role in peroxisomal metabolism of P. methanolica, including methanol metabolism, and in peroxisomal localization and activation of methanol‐metabolizing enzymes, e.g. AOD isozymes, DHAS and CTA. Copyright © 2007 John Wiley & Sons, Ltd.
Kinetisch unbestimmte Systeme
Authors: Grammel R. 
Published: May 2007

AbstractDem Begriffe des statisch unbestimmten Systems hat L. Prandtl den Begriff des elastisch unbestimmten Systems an die Seite gestellt. Von der Statik zur Kinetik fortschreitend kommt man auf den weiteren Begriff der kinetisch unbestimmten Systeme. Darunter verstehe ich solche, deren Bewegung sich mit den Grundgesetzen der Stereokinetik überhaupt nicht ermitteln läßt, oder, etwas genauer gesagt: für deren Bewegung die Stereokinetik unendlich viele Lösungen liefert, unter denen die tatsächlich eintretende nur dann gefunden werden kann, wenn man die Idee des starren Körpers aufgibt, Systeme also, die den Geltungsbereich der Idee des starren Körpers ebenso überschreiten, wie dies die statisch unbestimmten Systeme in ihrer Art tun. Kinetisch unbestimmte Systeme in diesem Sinne kommen vereinzelt in der Mechanik schon lange vor (z. B. der “halbelastische” Stoß zweier “starrer” Körper, wobei die fehlende kinetische Gleichung durch die phänomenologische Annahme einer nur stoffabhängigen Stoßzahl ersetzt wird); aber systematisch scheint dieser Begriff bis jetzt nicht untersucht worden zu sein. Im folgenden will ich einige der wichtigsten Klassen von kinetisch unbestimmten Systemen aufzählen und durch Beispiele belegen.
Tissue‐Engineered Bone Formation With Gene Transfer and Mesenchymal Stem Cells in a Minimally Invasive Technique
Authors: Park Dong‐Joon , Choi Jin Hyun , Leong Kam W. , Kwon Jang‐Woo , Eun Hee Seog 
Published: May 2007

AbstractBackground: The objective of this study was to use a chitosan‐alginate gel to implant bone marrow‐derived mesenchymal stem cells subcutaneously in a minimally invasive manner and promote bone formation by the simultaneously transferred osteogenic protein (OP)‐1 (bone morphogenic protein‐7) gene.Method and Results: The complex of polyethylenimine/luciferase plasmid DNA embedded in the gel was able to transfect HEK 293 cells on a culture dish or co‐encapsulated in the gel. When injected into the subcutaneous space of mice, luciferase expression was two to three orders of magnitude increased above the background. To examine the efficacy of gene‐, cell‐, and combined gene‐ and cell‐encapsulated gels in tissue generation, samples were injected into the subcutaneous space of 6‐week‐old athymic nude mice, and the OP‐1 plasmid was studied. At 8 weeks after the injection, the gels only maintained their volumetric shape when human mesenchymal stem cells (hMSCs) were encapsulated, but otherwise the gels were partially dissolved. Transgene expression of OP‐1 was clearly detected in the samples after 4 weeks but not after 8 weeks. Type II collagen was detected in all the gels containing the OP‐1 plasmid, with or without hMSCs. The samples with the combination of OP‐1 DNA and hMSCs revealed strong type II collagen expression as well as osteoid foci.Conclusion: These results suggest that combined gene and hMSC delivery within a chitosan‐alginate gel could be an interesting approach for tissue engineering.
Litter decomposition in a Cerrado savannah stream is retarded by leaf toughness, low dissolved nutrients and a low density of shredders
Authors: GONÇALVES J. F. , GRAÇA M. A. S. , CALLISTO M. 
Published: May 2007

Summary1. To assess whether the reported slow breakdown of litter in tropical Cerrado streams is due to local environmental conditions or to the intrinsic leaf characteristics of local plant species, we compared the breakdown of leaves from Protium brasiliense, a riparian species of Cerrado (Brazilian savannah), in a local and a temperate stream. The experiment was carried out at the time of the highest litter fall in the two locations. An additional summer experiment was conducted in the temperate stream to provide for similar temperature conditions.2. The breakdown rates (k) of P. brasiliense leaves in the tropical Cerrado stream ranged from 0.0001 to 0.0008 day−1 and are among the slowest reported. They were significantly (F = 20.12, P < 0.05) lower than in the temperate stream (0.0046–0.0055). The maximum ergosterol content in decomposing leaves in the tropical Cerrado stream was 106 μg g−1, (1.9% of leaf mass) measured by day 75, which was lower than in the temperate stream where maximum ergosterol content of 522 μg g−1 (9.5% of leaf mass) was achieved by day 30. The ATP content, as an indicator of total microbial biomass, was up to four times higher in the tropical Cerrado than in the temperate stream (194.0 versus 49.4 nmoles g−1).3. Unlike in the temperate stream, leaves in the tropical Cerrado were not colonised by shredder invertebrates. However, in none of the experiments did leaves exposed (coarse mesh bags) and unexposed (fine mesh bags) to invertebrates differ in breakdown rates (F = 1.15, P > 0.05), indicating that invertebrates were unable to feed on decomposing P. brasiliense leaves.4. We conclude that the slow breakdown of P. brasiliense leaves in the tropical Cerrado stream was because of the low nutrient content in the water, particularly nitrate (0.05 mgN L−1), which slows down fungal activity and to the low density of invertebrates capable of using these hard leaves as an energy source.
Temporal environmental change, clonal physiology and the genetic structure of aDaphniaassemblage (D. galeata–hyalinahybrid species complex)
Authors: PINKHAUS OLAF , SCHWERIN SUSANNE , PIROW RALPH , ZEIS BETTINA , BUCHEN INA , GIGENGACK ULRIKE , KOCH MARITA , HORN WOLFGANG , PAUL RÜDIGER J. 
Published: May 2007

Summary1. In a combined field and laboratory study, seasonal relationships between water temperature and oxygen content, genetic structure (composition of MultiLocus Genotypes, MLGs) of aDaphniaassemblage (D. galeata–hyalinahybrid species complex), and the physiological properties of clones of frequent MLGs were studied. In accordance with the oxygen‐limited thermal tolerance hypothesis, essential physiological variables of oxygen transport and supply were measured within the tolerable temperature range.2. A few MLGs (types T1–T4) were frequent during early spring and late autumn at surface temperatures below 10 °C. Clones of T1–T4 showed a low tolerance towards higher temperatures (above 20 °C) and a high phenotypic plasticity under thermal acclimation in comparison to clones derived from frequent MLGs from later seasons, and stored high–medium quantities of carbohydrates at 12 and 18 °C.3. Another MLG (T6) succeeded the MLGs T1–T4. T6 was frequent over most of the year at temperatures above 10 °C and below 20 °C. A clone derived from T6 exhibited a high tolerance towards warm temperatures and a more restricted phenotypic plasticity. It stored high–medium quantities of carbohydrates at 12, 18 and 24 °C and showed a high capacity for acclimatory adjustments based on haemoglobin expression.4. During the summer period at temperatures ≥20 °C, the MLG T6 was found mainly near to the thermocline, where temperature and oxygen content were distinctly lower, and to a lesser extent in surface water. At the surface, another MLG (T19) was predominant during this period. A clone of this MLG showed a very high tolerance towards warm temperatures, minimal phenotypic plasticity, low carbohydrate stores and a high capacity for circulatory adjustments to improve oxygen transport at higher temperatures.5. This study provides evidence for connections between the spatio‐temporal genetic heterogeneity of aDaphniaassemblage and the seasonal changes of water temperature and oxygen content. The data also suggest that not only the actual temperature but also the dynamics of temperature change may influence the genetic structure ofDaphniapopulations and assemblages.
Comparison of waveform inversion, part 3: amplitude approach
Authors: Pyun Sukjoon , Shin Changsoo , Bednar J. B. 
Published: May 2007

ABSTRACTIn the second paper of this three part series, we studied the case of conventional and logarithmic phase‐only approaches to full‐waveform inversion. Here, we concentrate on deriving amplitude‐only approaches for both conventional‐ and logarithmic‐based methods. We define two amplitude‐only objective functions by simply assuming that the phase of the modelled wavefield is equal to that of the observed wavefield. We do this for both the conventional least‐squares approach and the logarithmic approach of Shin and Min. We show that these functions can be optimized using the same reverse‐time propagation algorithm of the full conventional methodology. Although the residuals in this case are not really residual wavefields, they can both be considered and utilized in that sense. In contrast to the case for our phase‐only algorithms, we show through numerical tests that the conventional amplitude‐only inversion is better than the logarithmic method.
Impacts of Hurricane Frances on Florida scrub‐oak ecosystem processes: defoliation, net CO2 exchange and interactions with elevated CO2
Authors: LI JIAHONG , POWELL THOMAS L. , SEILER TROY J. , JOHNSON DAVID P. , ANDERSON HANS P. , BRACHO ROSVEL , HUNGATE BRUCE A. , HINKLE CHARLES R. , DRAKE BERT G. 
Published: May 2007

AbstractHurricane disturbances have profound impacts on ecosystem structure and function, yet their effects on ecosystem CO2 exchange have not been reported. In September 2004, our research site on a fire‐regenerated scrub‐oak ecosystem in central Florida was struck by Hurricane Frances with sustained winds of 113 km h−1 and wind gusts as high as 152 km h−1. We quantified the hurricane damage on this ecosystem resulting from defoliation: we measured net ecosystem CO2 exchange, the damage and recovery of leaf area, and determined whether growth in elevated carbon dioxide concentration in the atmosphere (Ca) altered this disturbance. The hurricane decreased leaf area index (LAI) by 21%, which was equal to 60% of seasonal variation in canopy growth during the previous 3 years, but stem damage was negligible. The reduction in LAI led to a 22% decline in gross primary production (GPP) and a 25% decline in ecosystem respiration (Re). The compensatory declines in GPP and Re resulted in no significant change in net ecosystem production (NEP). Refoliation began within a month after the hurricane, although this period was out of phase with the regular foliation period, and recovered 20% of the defoliation loss within 2.5 months. Full recovery of LAI, ecosystem CO2 assimilation, and ecosystem respiration did not occur until the next growing season. Plants exposed to elevated Ca did not sustain greater damage, nor did they recover faster than plants grown under ambient Ca. Thus, our results indicate that hurricanes capable of causing significant defoliation with negligible damage to stems have negligible effects on NEP under current or future CO2‐enriched environment.
Manual superscaffolding of honey bee (Apis mellifera) chromosomes 12–16: implications for the draft genome assembly version 4, gene annotation, and chromosome structure
Authors: Robertson Hugh M. , Reese Justin T. , Milshina Natalia V. , Agarwala Richa , Solignac Michel , Walden Kimberly K. O. , Elsik Christine G. 
Published: May 2007

AbstractThe euchromatic arms of the five smallest telocentric chromosomes in the honey bee genome draft Assembly v4 were manually connected into superscaffolds. This effort reduced chromosomes 12–16 from 30, 21, 25, 42, and 21 mapped scaffolds to five, four, five, six, and five superscaffolds, respectively, and incorporated 178 unmapped contigs and scaffolds totalling 2.6 Mb, a 6.4% increase in length. The superscaffolds extend from the genetically mapped location of the centromere to their identified distal telomeres on the long arms. Only two major misassemblies of 146 kb and 65 kb sections were identified in this 23% of the mapped assembly. Nine duplicate gene models on chromosomes 15 and 16 were made redundant, while another 15 gene models were improved, most spectacularly the MAD (MAX dimerization protein) gene which extends across 11 scaffolds for at least 400 kb.