bluuebunny/crossref_metadata_2025 huggingface dataset:
Free Energy Calculations Using Flexible‐Constrained, Hard‐Constrained and Non‐Constrained Molecular Dynamics Simulations
Authors: Christen Markus , Christ Clara D. , van Gunsteren Wilfred F.
Published: June 2007

A comparison of different treatments of bond‐stretching interactions in molecular dynamics simulation is presented. Relative free energies from simulations using rigid bonds maintained with the SHAKE algorithm, using partially rigid bonds maintained with a recently introduced flexible constraints algorithm, and using fully flexible bonds are compared in a multi‐configurational thermodynamic integration calculation of changing liquid water into liquid methanol. The formula for the free energy change due to a changing flexible constraint in a flexible constraint simulation is derived. To allow for a more direct comparison between these three methods, three different pairs of models for water and methanol were used: a flexible model (simulated without constraints and with flexible constraints), a rigid model (simulated with standard hard constraints), and an alternative flexible model (simulated with flexible constraints and standard hard constraints) in which the ideal or constrained bond lengths correspond to the average bond lengths obtained from a short simulation of the unconstrained flexible model. The particular treatment of the bonds induces differences of up to 2 % in the liquid densities, whereas (excess) free energy differences of up to 5.7 (4.3) kJ mol−1 are observed. These values are smaller than the differences observed between the three different pairs of methanol/water models: up to 5 % in density and up to 8.5 kJ mol−1 in (excess) free energy.
Structure‐Dependent Photophysics Studied in Single Molecules of Polythiophene Derivatives
Authors: Sugimoto Toshikazu , Ebihara Yohei , Ogino Kenji , Vacha Martin
Published: June 2007

We report on the photophysical characterization at the single‐molecule level of a graft copolymer consisting of a polythiophene backbone and long polystyrene branches. The presence of the branches prevents the polymer chain from forming a collapsed conformational state. The photophysical properties of the resulting solution‐like conformation are studied by measuring single‐molecule photobleaching dynamics, emission polarization anisotropy and emission spectra. The results are compared with those obtained on the same polythiophene derivative without the branches. It is found that the presence of the branches is a decisive factor in determining the photophysical properties of the polymers on the single‐molecule level.
Energy‐efficient target detection in sensor networks using line proxies
Authors: Lee Jangwon , Yu Wei , Fu Xinwen
Published: June 2007

One of the fundamental and important operations in sensor networks is sink–source matching, i.e. target detection. Target detection is about how a sink finds the location of source nodes observing the event of interest (i.e. target activity). This operation is very important in many sensor network applications such as military battlefield and environment habitats. The mobility of both targets and sinks brings significant challenge to target detection in sensor networks. Most existing approaches are either energy inefficient or lack of fault tolerance in the environment of mobile targets and mobile sinks. Motivated by these, we propose an energy‐efficient line proxy target detection (LPTD) approach in this paper.
The basic idea of LPTD is to use designated line proxies as rendezvous points (or agents) to coordinate mobile sinks and mobile targets. Instead of having rendezvous nodes for each target type as used by most existing approaches, we adopt the temporal‐based hash function to determine the line in the given time. Then the lines are alternated over time in the entire sensor network. This simple temporal‐based line rotation idea allows all sensor nodes in the network to serve as rendezvous points and achieves overall load balancing. Furthermore, instead of network‐wide flooding, interests from sinks will be flooded only to designated line proxies within limited area. The interest flooding can further decrease if the interest has geographical constraints. We have conducted extensive analysis and simulations to evaluate the performance of our proposed approach. Our results show that the proposed approach can significantly reduce overall energy consumption and target detection delay. Copyright © 2007 John Wiley & Sons, Ltd.
Crystalline bodies in Pap smear—A forgotten entity
Authors: Kapila Kusum , Al‐Juwaiser Ahlam , Haji Bahiyah E.
Published: June 2007

Crystalline bodies were detected in the Pap smear of a 34‐wk pregnant woman who presented with postcoital bleeding. Diagn. Cytopathol. 2007;35:423. © 2007 Wiley‐Liss, Inc.
The fine needle aspiration biopsy diagnostic criteria of proliferative breast lesions: A retrospective statistical analysis of criteria for papillomas and radial scar lesions
Authors: Field Andrew , Mak Alison
Published: June 2007

This study aimed to analyze statistically the accuracy of fine needle aspiration biopsy cytological criteria in diagnosing epithelial hyperplasia with atypia (EHA), papillary lesions (PAP), and radial scar/complex sclerosing lesions (RS/CSL). The 42 criteria studied were extracted from a literature review and those developed and used in our department.

Cytological cases with diagnoses of EHA, PAP, and RS/CSL for the period of 1997–2001 were correlated with relevant histological follow‐up and the positive predictive power of these diagnoses have been presented in an earlier publication. Some 77 cases with definite, specific histological diagnoses of atypia or a more severe lesion, PAP and RS/CSL, were reviewed and scored using 55 cytological criteria.

As the group of EHA and RS/CSL yielded a smaller number of cases, these were grouped together in the statistical analysis and compared to PAP. The cytological features, which were most diagnostic for PAP, were stellate (Odds ratio 1.75) and meshwork (Odds ratio 3.29) tissue fragments, while the presence of tubular structures was inversely proportional to the histological outcome of PAP. True papillary fragments were uncommon and not statistically significant in diagnosing PAP of the breast. Diagn. Cytopathol. 2007;35:386–397. © 2007 Wiley‐Liss, Inc.
Ciliated foregut cyst of pancreas: Cytologic findings on endoscopic ultrasound‐guided fine‐needle aspiration
Authors: Woon Carolyn S. , Pambuccian Stefan E. , Lai Rebecca , Jessurun Jose , Gulbahce H. Evin
Published: June 2007

The cytologic findings of a ciliated foregut cyst of the pancreas diagnosed by endoscopic ultrasound‐guided fine‐needle aspiration (FNA) are described. Cytologic features of ciliated foregut cysts include the presence of ciliated columnar cells and detached ciliary tufts in a cystic fluid background with amorphous debris and rare macrophages. These cytologic findings are clearly distinct from those of cystic mucinous neoplasms and other pancreatic cysts with which the ciliated foregut cyst may be confused. To the best of our knowledge, this is the first case reporting the cytologic findings of a pancreatic ciliated foregut cyst sampled by endoscopic ultrasound‐guided FNA. We believe that the distinctive and characteristic cytologic features can allow a preoperative cytologic diagnosis of this highly unusual pancreatic cystic lesion. Diagn. Cytopathol. 2007;35:433–438. © 2007 Wiley‐Liss, Inc.
Cytological study of 20 cases of solid‐papillary carcinoma of the breast
Authors: Yamada Makoto , Otsuki Yoshiro , Shimizu Shin‐ichi , Tanioka Fumihiko , Ogawa Hiroshi , Kobayashi Hiroshi
Published: June 2007

Solid‐papillary carcinoma (SPC) of the breast is a rare variant of low‐grade intraductal carcinoma but there are few cytological studies. We examined 20 cases of SPC of the breast, aged 31–80 (mean age 66.0 yr), to define the cytological features. In each of the cytological specimens, we could find both malignant and benign cytological features; the former were characterized by hypercellularity, highly discohesive clusters, numerous isolated cells, and severe overcrowding cells, while the latter were marked by small and bland nuclei, a low nuclear‐cytoplasmic ratio, and inconspicuous nucleoli. Neither abnormal naked nuclei of tumor cell origin nor oval naked nuclei of myoepithelial cell origin were seen.

We also reviewed the cytological findings of SPC as well as neuroendocrine carcinomas with intraductal components that had been reported and we concluded that the coexistence of malignant and benign features was the most characteristic cytological feature of SPC. Diagn. Cytopathol. 2007;35:417–422. © 2007 Wiley‐Liss, Inc.
Anomeric Interactions in Pentafluoroethylimidosulfurous Dichloride, CF3CF2N=SCl2: Structural, Conformational and Configurational Properties in the Gaseous and Condensed Phases
Authors: Robles Norma L. , Álvarez Rosa M. S. , Cutin Edgardo H. , Della Védova Carlos O. , Erben Mauricio F. , Boese Roland , Willner Helge , Mews Rüdiger
Published: June 2007

The structural, conformational, and configurational properties of pentafluoroethylimidosulfurous dichloride (CF3CF2N=SCl2) have been studied by vibrational spectroscopy [IR (vapor) and Raman (liquid)] and quantum chemical calculations [HF, B3LYP and MP2 approximations using the 6‐311+G(d) and 6‐311+G(2df) basis sets]. CF3CF2N=SCl2 exists in the liquid phase as a single (Z) form (C–N bond synperiplanar with respect to the Cl–S–Cl plane; C1 symmetry). The structure was also determined by X‐ray diffraction analysis of a single crystal grown in situ at low temperature. The crystalline solid at 159 K (monoclinic, P21/c, a = 5.2466(10), b = 15.376(3), c = 18.730(3) Å, β = 96.391(3)°, Z = 8) consists of two crystallographically inequivalent (Z) forms. The results are discussed in terms of both hyperconjugative electronic effects and of natural bond orbital (NBO) calculations. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Chlorido‐Bridged MnII Schiff‐Base Complex with Ferromagnetic Exchange Interactions
Authors: Qi Chuan‐Min , Sun Xu‐Xia , Gao Song , Ma Shu‐Lan , Yuan Da‐Qiang , Fan Cui‐Hong , Huang Hai‐Bo , Zhu Wen‐Xiang
Published: June 2007

The preparation, crystal structure, and magnetic properties of the μ‐Cl‐bridged dinuclear complex [Mn(HL)(μ‐Cl)Cl]2 (1) with the Schiff‐base ligand HL, 2‐methyl‐6‐[(pyridine‐2‐ylmethylene)amino]phenol, is reported. Structural studies show that 1 is binuclear with a pair of chlorine atoms bridging the manganese atoms in a central Mn2Cl2 plane, the intramolecular Mn···Mn separation being 3.694 Å. Each manganese atom in 1 is six‐coordinate with two nitrogen atoms (one imine nitrogen and one pyridine nitrogen) and one phenolic oxygen from the neutral tridentate ligand, and three chlorine atoms (one terminal and two bridging) building an elongated octahedral environment. The two octahedra adopt the unique geometry sharing an equatorial‐to‐axial edge with parallel equatorial planes. The hydrogen bonds between the coordinated Cl– anions and hydroxy groups connect the dimeric coordinated units together forming a one‐dimensional chain. Variable temperature susceptibility measurements in the temperature range of 2.0–300 K reveal a ferromagnetic coupling (J = +0.94 cm–1) in the dimer via the double chlorido bridge, and a weak antiferromagnetic coupling (zJ′ = –0.036 cm–1) between the dimers through the intermolecular hydrogen bonding. A comparison of the magnetic coupling of 1 with other structurally similar Mn(μ‐Cl)2Mn compounds is discussed in detail. Complex 1 may provide useful information for the magneto‐structural correlations of this kind of compounds. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Advances in the Synthesis of Aryltetralin Lignan Lactones
Authors: Sellars Jonathan D. , Steel Patrick G.
Published: June 2007

Etoposide and tenoposide, derivatives of the aryltetralin lignan lactone podophyllotoxin (5), are clinically important anticancer agents. The structure of podophyllotoxin includes four contiguous chiral centres contained within a stereochemically unstable trans‐fused tetrahydronaphthalene lactone skeleton. Reflecting this challenging structure and important biological role there has been long‐standing interest in developing efficient stereocontrolled syntheses of this class of natural product. This microreview summarises the key developments towards this end focussing on more recent developments both from within the authors group and elsewhere.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Novel Cyclic Phosphate‐Linked Oligosaccharides (CyPLOSs) Covalently Immobilized on Solid Supports for Potential Cation Scavenging
Authors: D'Onofrio Jennifer , Coppola Cinzia , Di Fabio Giovanni , De Napoli Lorenzo , Montesarchio Daniela
Published: June 2007

For potential cation scavenging both from water and from organic solvents, here we propose a synthetic procedure for functionalization of a Tentagel solid support with novel cyclic phosphate‐linked oligosaccharide (CyPLOS) analogues. To establish the feasibility of the synthetic strategy, the cyclic dimer was the model compound selected to be incorporated onto the solid support. This functionalization was achieved through a stepwise solid‐phase synthesis of the linear dimer, obtained by standard phosphoramidite protocols, followed by a synthesis of the cyclic molecule on the resin. The key intermediate in our synthetic strategy was a suitably derivatized sugar phosphoramidite building block, with the secondary hydroxy functions masked as TBDMS ethers. This proved to be an orthogonal protection with respect to the DMT ether, fully compatible with the phosphoramidite and the phosphotriester chemistry used for the oligomerization and the cyclization process onto the solid support, respectively. Conditions for the total unmasking of the hydroxy groups of the cyclic dimer, not affecting the integrity of the cyclic structure nor its linkage with the solid matrix, have been optimized. Gel‐phase31P NMR spectroscopy has been used extensively here to monitor the efficiency of the reactions carried out on the solid support.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Synthesis and Structure of an α,β‐D‐CNA Featuring a Noncanonical α/β Torsion Angle Combination within a Tetranucleotide
Authors: Le Clézio Ingrid , Dupouy Christelle , Lavedan Pierre , Escudier Jean‐Marc
Published: June 2007

Synthesis and structural analysis of a (SC5′,RP)‐configured α,β‐D‐CNA TT within a tetranucleotide composed of four thymidine units showed that the solution structure determined at the dinucleotide level for the α,β‐D‐CNA with α and β torsional angles constrained to noncanonical values [gauche(+), trans] was unchanged and imposed a sharp turn in the single‐stranded tetranucleotide. The overall structure of the tetranucleotide T4 has a hairpin loop shape. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Multiplex PCR with minisequencing as an effective high‐throughput SNP typing method for formalin‐fixed tissue
Authors: Gilbert Marcus T. P. , Sanchez Juan J. , Haselkorn Tamara , Jewell Laurence D. , Lucas Sebastian B. , Van Marck Eric , Børsting Claus , Morling Niels , Worobey Michael
Published: June 2007

Extensive collections of formalin‐fixed paraffin‐embedded (FFPE) tissues exist that could be exploited for genetic analyses in order to provide important insights into the genetic basis of disease or host/pathogen cointeractions. We report here an evaluation of a 44 SNP multiplex genotyping method, multiplex PCR with minisequencing (MPMS), on 92 DNA extractions performed on six archival FFPE samples of variable DNA quality, which date between 9 and 25 years old. On the three extracts with highest quality, we found the assay efficiency to be near 100%. However, the efficiency of the lowest quality extracts varied significantly. In this study, we demonstrate that although direct measures of DNA concentration in the extracts provide no useful information with regard to subsequent MPMS success, the success of the assay can be determined to some degree a priori, through initial screening of the DNA quality using a simple quantitative real‐time PCR (qPCR) assay for nuclear DNA, and/or an assay of the maximum PCR amplifiable size of nuclear DNA. MPMS promises to be of significant use in future genetic studies on FFPE material. It provides a streamlined approach for retrieving a large amount of genetic information using simple, single reactions and minute amounts of archival tissue/DNA. In the light of this evidence, we suggest that the systematic screening of FFPE collections may in the future provide valuable insights into the past.
A hybrid microdevice with a thin PDMS membrane on the detection window for UV absorbance detection
Authors: Ma Bo , Zhou Xiaomian , Wang Gang , Dai Zhongpeng , Qin Jianhua , Lin Bingcheng
Published: June 2007

We exploited a PDMS‐quartz hybrid microchip with a thin PDMS membrane on the concave detection window for UV absorbance detection. The thickness of the PDMS membrane is about 100 μm, with high UV transmittance. As compared to a PDMS‐quartz hybrid chip with a common detection window, the proposed one exhibited over an one order of magnitude sensitivity enhancement, and an about two orders of magnitude S/N increase for gastrodin (p‐hydroxymethylphenyl‐β‐D‐glucopyranoside). In addition, the limit of the detection wavelength has been extended from 240 to 210 nm, which is otherwise impossible for a traditional PDMS‐quartz hybrid microchip. This kind of microchip has the potential for a large range of applications in an integrated microfluidic system with UV detection.
Rapidly profiling blood–brain barrier penetration with liposome EKC
Authors: Wang Yongjun , Sun Jin , Liu Hongzhuo , He Zhonggui
Published: June 2007

This report intended to study the potential of liposome EKC (LEKC) as a convenient and high‐throughput screening tool to assess drug penetration across the blood–brain barrier (BBB). The retention factors (k) of 24 structurally diverse compounds were determined with LEKC and vesicle EKC (VEKC), respectively. Principal component analysis of the steady‐state concentrations ratio of compounds in the brain and in the blood expressed as log BB, log kLEKC, log kVEKC, and other lipophilic descriptors including octanol/water partition coefficient (Clog P), octanol/water distribution coefficients (log D7.4), and polar surface area (PSA), showed the maximum similarity of partitioning processes in LEKC to drug penetration across the BBB. Furthermore, the log BB were correlated with the above five lipophilic descriptors, and the results showed that log kLEKC gave the better correlation coefficient (r2 = 0.811, p <0.0001) than those of log D7.4, Clog P, PSA, and log kVEKC (r2 = 0.730, 0.672, 0.627, and 0.620, p <0.0001). This is the first report of the use of LEKC as a promising rapid tool to profile drug penetration across the BBB.
Isolation of smooth‐type lipopolysaccharides to electrophoretic homogeneity
Authors: Pupo Elder , Hardy Eugenio
Published: June 2007

The high structural heterogeneity of smooth‐type lipopolysaccharides (LPS) enormously complicates the isolation of their constituent molecular species. Proof of concept is given here on the feasibility of using preparative slab‐PAGE to isolate highly homogeneous smooth‐type LPS glycoforms. LPS species (from 3.6 to 14.2 kDa) from Escherichia coli K‐235 were separated by preparative slab‐PAGE and recovered by utilizing the combined on‐gel LPS reverse staining, extrusion, and passive elution techniques. As a result, 15 electrophoretically pure LPS fractions were obtained. The LPS content in the recovered fractions ranged from 280 ng (intermediate mobility glycoforms) to 411 μg (highest mobility glycoforms). The quantities of LPS fractions were sufficient to allow quantitation of the Limulus amebocyte lysate (LAL) activities of these distinct‐molecular‐mass LPS species, in the range from (1.1 ± 0.1)×103 to (8.7 ± 0.3)×105 endotoxin units (EU)/mL, by standard LAL assay. We have thus definitively demonstrated that slab‐PAGE may be a suitable platform to more selectively purify individual glycoform fractions from smooth‐type LPS.
Investigating nonlinear speculation in cattle, corn, and hog futures markets using logistic smooth transition regression models
Authors: Röthig Andreas , Chiarella Carl
Published: June 2007

This study explores nonlinearities in the response of speculators' trading activity to price changes in live cattle, corn, and lean hog futures markets. Analyzing weekly data from March 4, 1997 through December 27, 2005, the authors reject linearity in all of these markets. Using smooth transition regression models, the authors found a similar structure of nonlinearities with regard to the number of different regimes, the choice of the transition variable, and the value at which the transition occurs. © 2007 Wiley Periodicals, Inc. Jrl Fut Mark 28:719–737, 2007
Canonical valuation and hedging of index options
Authors: Gray Philip , Edwards Shane , Kalotay Egon
Published: June 2007

Canonical valuation is a nonparametric method for valuing derivatives proposed by M. Stutzer (1996). Although the properties of canonical estimates of option price and hedge ratio have been studied in simulation settings, applications of the methodology to traded derivative data are rare. This study explores the practical usefulness of canonical valuation using a large sample of index options. The basic unconstrained canonical estimator fails to outperform the traditional Black–Scholes model; however, a constrained canonical estimator that incorporates a small amount of conditioning information produces dramatic reductions in mean pricing errors. Similarly, the canonical approach generates hedge ratios that result in superior hedging effectiveness compared to Black–Scholes‐based deltas. The results encourage further exploration and application of the canonical approach to pricing and hedging derivatives. © 2007 Wiley Periodicals, Inc. Jnl Fut Mark 27: 771–790, 2007
Richardson extrapolation techniques for the pricing of American‐style options
Authors: Chang Chuang‐Chang , Chung San‐Lin , Stapleton Richard C.
Published: June 2007

In this article, the authors reexamine the American‐style option pricing formula of R. Geske and H.E. Johnson (1984), and extend the analysis by deriving a modified formula that can overcome the possibility of nonuniform convergence (which is likely to occur for nonstandard American options whose exercise boundary is discontinuous) encountered in the original Geske–Johnson methodology. Furthermore, they propose a numerical method, the Repeated‐Richardson extrapolation, which allows the estimation of the interval of true option values and the determination of the number of options needed for an approximation to achieve a given desired accuracy. Using simulation results, our modified Geske–Johnson formula is shown to be more accurate than the original Geske–Johnson formula for pricing American options, especially for nonstandard American options. This study also illustrates that the Repeated‐Richardson extrapolation approach can estimate the interval of true American option values extremely well. Finally, the authors investigate the possibility of combining the binomial Black–Scholes method proposed by M. Broadie and J.B. Detemple (1996) with the Repeated‐Richardson extrapolation technique. © 2007 Wiley Periodicals, Inc. Jrl Fut Mark 27:791–817, 2007
Influence of the surface structure of a multiblock copolymer on the cellular behavior of primary cell cultures of the upper aerodigestive tract in vitro
Authors: Rickert Dorothee , Franke R.‐P. , Lendlein A. , Kelch S. , Moses M.A.
Published: June 2007

The influence of the surface topography of a biodegradable copolymer on adhesion, proliferation, and cellular activity of primary cell cultures of the upper aerodigestive tract (ADT) was investigated. On the basis of the important functions of matrix metalloproteinases (MMPs) and their endogenous inhibitors, tissue inhibitor of MMPs (TIMPs) in regulating extracellular matrix remodeling, cellular adhesion and growth, the appearance and kinetics of these enzymes were investigated in primary cells of the upper ADT seeded on different surfaces of a polymeric biomaterial. Primary cell cultures of the upper ADT of Sprague‐Dawley rats were seeded on different surfaces (smooth versus rough surface) of a biodegradable multiblock copolymer and on polystyrene surface as control. Conditioned media of the primary cells were analyzed for MMPs and TIMPs by both zymography and radiometric enzyme assay. Cell adhesion and proliferation as well as the kinetics of appearance and activity level of MMP‐1, MMP‐2, and TIMPs were significantly different depending on the cell type and the surface structure of the multiblock copolymer. In this study, the data obtained indicated that surface topography governed the biological response to biomaterials. Knowledge as to how cells interact with the interface of biomaterials will be necessary in order to eventually design the “ideal” surface of biomaterials, which will be both tissue and organ‐optimized in order to best provide clinicians with specific and viable novel therapeutical options in medicine. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2007
Degradation and biocompatibility of a poly(propylene fumarate)‐based/alumoxane nanocomposite for bone tissue engineering
Authors: Mistry A.S. , Mikos A.G. , Jansen J.A.
Published: June 2007

In this work, we evaluated the in vitro cytotoxicity and in vivo biocompatibility of a novel poly(propylene fumarate) (PPF)‐based/alumoxane nanocomposite for bone tissue engineering applications. The incorporation of functionalized alumoxane nanoparticles into the PPF‐based polymer was previously shown to significantly increase the material's flexural mechanical properties. In the current study, samples underwent accelerated in vitro degradation to allow the study of biological responses to these materials over the course of their degradation on a shortened timescale. The polymer, a macrocomposite composed of the polymer and micron‐sized particles, and the nanocomposite were evaluated at three stages of degradation for in vitro cytotoxicity with a fibroblast cell line and in vivo soft‐tissue response after 3 and 12 weeks of implantation in adult goats. All three material groups experienced mass loss during degradation, but the nanocomposite group eroded significantly faster than the other groups. Nondegraded materials demonstrated minimal cytotoxicity and a minor inflammatory response in soft tissue. On the contrary, predegraded samples elicited more pronounced responses, though these were due to the increase in surface area, surface roughness, and fragmentation associated with the degradation process. The presence of alumoxane nanoparticles in the PPF‐based nanocomposite did not significantly affect its cytotoxicity or biocompatibility. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2007
Characterization of the surface immobilized synthetic heparin binding domain derived from human fibroblast growth factor‐2 and its effect on osteoblast differentiation
Authors: Lee Jue‐Yeon , Choo Jung‐Eun , Choi Young‐Sook , Lee Kuen‐Yong , Min Do‐Sik , Pi Sung‐Hee , Seol Yang‐Jo , Lee Seung‐Jin , Jo In‐Ho , Chung Chong‐Pyoung , Park Yoon‐Jeong
Published: June 2007

Fibroblast growth factor (FGF)‐2 regulates a variety of cellular functions, such as proliferation and differentiation, by binding to cell surface FGF receptors (FGFRs) in the presence of heparin proteoglycans. FGF‐2 is known as a heparin‐binding growth factor, but the localization of the heparin binding site has not been fully investigated until now. We used two potential heparin binding domains of FGF‐2, the residues 105–111 (F105, YKRSRYT) and 119–135 (F119, KRTGQYKLGSKTGPGQK). Peptides could be stably immobilized onto the surface of tissue culture plates. Using solid phase binding assays, we demonstrated that both peptides had higher binding affinity toward heparin compared with nonbinding control sequence. The biological significance of these sites was tested by cell attachment and osteoblast differentiation studies. Cell attachment to the peptides F105 and F119 increased in a dose‐dependent manner. Heparin and heparinase treatments decreased cell adhesion to both F105 and F119. This demonstrates that both F105 and F119 interact with cell‐surface heparan sulfate proteoglycans, suggesting that FGF‐2 has two heparin binding sites. In addition, osteoblast differentiation, confirmed by ALPase activity and mineralization, was increased by surface immobilized peptide F105 and F119. Taken together, these heparin binding peptides could be applied as biological agents enhancing osteoblast differentiation as well as surface modification tools in the tissue regeneration area, especially for bone regeneration. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2007
Osterix/Sp7 regulates mesenchymal stem cell mediated endochondral ossification
Authors: Kaback Lee A. , Soung Do Y. , Naik Amish , Smith Nathan , Schwarz Edward M. , O'Keefe Regis J. , Drissi Hicham
Published: June 2007

We investigated the expression and regulation of the zinc finger protein Osterix (Osx) during endochondral ossification in mice. In studies to determine the temporal and spatial regulation of Osx mRNA and protein during embryogenesis we found it to be present throughout development, but its expression is restricted to the immature chondro/osteoprogenitor cells and mature osteoblasts, excluding hypertrophic chondrocytes. Using a fracture model, we show a consistent pattern of Osx protein expression in mesenchymal progenitor cells in the periosteum and immature chondrocytes and osteoblasts embedded in the fracture callus. In contrast, hypertrophic chondrocytes, vessels and fibrous tissue were devoid of Osx expression. Additionally, using RNA isolated from fracture callus throughout the healing process, we observe that Osx transcripts parallel that of Runx2 and differentially overlap both cartilage and bone phenotypic markers. Furthermore, using limb bud‐derived MLB13MYC Clone 17 cells, we show that PTHrP inhibited chondrocyte maturation while it enhanced mRNA levels of Osx in these chondro/osteoprogenitor cells. Gain and loss of function of Osx function experiments with these cells demonstrated that Osx serves as an inhibitor of chondrogenesis and chondrocyte maturation, while it promotes osteoblast maturation. Together, our findings provide the first demonstration of the molecular mechanisms underlying Osx inhibition of chondrocyte differentiation, and further suggest a role for this transcription factor in mediating endochondral ossification during bone repair. J. Cell. Physiol. 214:173–182, 2008. © 2007 Wiley‐Liss, Inc.
Enhanced VDUP‐1 gene expression by PPARγ agonist induces apoptosis in human macrophage
Authors: Billiet L. , Furman C. , Larigauderie G. , Copin C. , Page S. , Fruchart J.‐C. , Brand K. , Rouis M.
Published: June 2007

The fate and phenotype of lesion macrophages is regulated by cellular oxidative stress. Thioredoxin‐1 (Trx‐1) plays a major role in the regulation of cellular redox balance, with resultant effects on gene expression and cellular responses including cell growth and death. Trx‐1 activity is inhibited by interaction with vitamin D‐upregulated protein‐1 (VDUP‐1). Peroxisome proliferator‐activated receptor gamma (PPARγ) is expressed by human monocyte‐derived macrophages (HMDM) and PPARγ agonism has been reported to decrease expression of inflammatory genes and to promote apoptosis of these cells. To determine whether VDUP‐1 may be involved in regulating the effects of PPARγ agonists in macrophages, we investigated the effect of a synthetic PPARγ agonist (GW929) on the expression of VDUP‐1 in HMDM. GW929 concentration‐dependently increased HMDM expression of VDUP‐1 (mRNA and protein). Transfection of different fragments of the VDUP‐1 promoter as well as gel shift analysis revealed the presence of functional PPARγ response elements (PPRE) in the promoter. Under conditions in which PPAR agonism altered levels of VDUP‐1, caspase‐3 activity, and macrophage apoptosis were also elevated. The results suggest that PPARγ activation stimulates apoptosis in human macrophages by altering the cellular redox balance via regulation of VDUP‐1. J. Cell. Physiol. 214:183–191, 2008. © 2007 Wiley‐Liss, Inc.
The novel correlation of carbonic anhydrase II and anion exchanger 1 in gills of the spotted green pufferfish, Tetraodon nigrovirids
Authors: Tang C.H. , Lee T.H.
Published: June 2007

A novel relationship between branchial carbonic anhydrase II (CAII) and anion exchanger 1 (AE1) was investigated in the euryhaline spotted green pufferfish (Tetraodon nigroviridis). The immunoblots revealed that AE1 was only detected in the membrane fraction of gills while CAII can be probed both in the membrane and cytosol fractions of gills. CAII protein abundance in the membrane fraction is salinity dependent. Immunological detection of the membrane fraction CAII protein in gills showed 3.9‐fold higher in the hyposmotic (freshwater) group than the hyperosmotic (seawater;35‰) group. In contrast, there was no change in the protein level of cytosolic CAII between seawater and freshwater groups. The whole‐mount immunocytochemical staining demonstrated that both AE1 and CAII were colocalized to the Na+/K+‐ATPase‐immunoreactive cells in gill epithelium of the pufferfish. The interaction between CAII and AE1 was further identified by co‐immunoprecipitation because AE1 was detected in the immunoprecipitates of CAII and vice versa. Our results showed that in pufferfish gills CAII was not only expressed in the cytosol to produce the substrate for AE1 transport during Cl− influx but also associated with the plasma membrane via AE1. Obviously, it is essential for the physiological function of AE1 to interact with CAII in the membrane of gill Na+/K+‐ATPase‐immunoreactive cells. To our knowledge, this is the first study to demonstrate the interaction of branchial CAII and AE1 in fish. The novel correlation proposed a new model of Cl−/HCO3− transport in gills of the teleosts. J. Exp. Zool. 307A:411–418, 2007. © 2007 Wiley‐Liss, Inc.
Poverty, networks and location: the determinants of job‐search in South Africa
Authors: Hinks Timothy
Published: June 2007

Previous work into the decision to search or not for work when unemployed has found that local unemployment rates, education level and social networks are important in the case of South Africa. This paper introduces a number of additional variables in order to test what other factors are associated with this decision. It is found that previous work experience, job security of the households employed members, whether there is a state pensioner in the unemployed person's household, poverty and proximity to public transport are all connected to the decision to varying degrees. Copyright © 2007 John Wiley & Sons, Ltd.
Synthesis of [2H3]‐labelled sulfamethoxazole and its main urinary metabolites
Authors: Heinkele Georg , Mürdter Thomas E.
Published: June 2007

Sulfamethoxazole was labelled at positions 3, 5, and 4′ by H/D exchange in a mixture of 5% 2H2SO4 and 95% 2H2O (v/v) under reflux for 72h with good isotope incorporation and acceptable yield. Subsequently, [2H3]‐sulfamethoxazole‐N1‐glucuronide and [2H3]‐N4‐acetyl‐sulfamethoxazole were synthesized. Copyright © 2007 John Wiley & Sons, Ltd.
Use of isotope effects to determine enzyme mechanisms
Authors: Cleland W. W.
Published: June 2007

Isotope effects are a powerful tool for determining the mechanisms of enzymatic reactions. Methods for measurement of isotope effects are reviewed and the equations that describe observed isotope effects and permit determination of intrinsic isotope effects on the isotope‐sensitive step are presented. Aspartate transcarbamoylase is used as an example for how the kinetic mechanism can be determined by observing the size of an isotope effect as a function of the concentration of another substrate. Cytidine, adenosine and AMP deaminases are used to illustrate determining the relative rates of steps in the mechanism. Determination of chemical mechanism is illustrated by data for malic enzyme, OMP decarboxylase, aspartate transcarbamoylase, L‐ribulose‐5‐P 4‐epimerase, oxalate decarboxylase, tryptophan 2‐monooxygenase and the K58A mutant of aspartate aminotransferase when rescued by ammonia. Determination of transition state structure is illustrated by data for formate dehydrogenase, prephenate dehydrogenase, chorismate mutase, as well as for enzymes that catalyze phosphoryl and acyl transfer. Copyright © 2007 John Wiley & Sons, Ltd.
Expression of decorin, a small leucine‐rich proteoglycan, as a prognostic factor in soft tissue tumors
Authors: Matsumine Akihiko , Shintani Ken , Kusuzaki Katsuyuki , Matsubara Takao , Satonaka Haruhiko , Wakabayashi Toru , Iino Takahiro , Uchida Atsumasa
Published: June 2007

Background and Objectives

Decorin is a major extracellular matrix protein which has recently become the focus of various cancer studies. However, there have so far been no reports describing the clinicopathological implications of decorin in soft tissue tumors. The aim of this study was to examine whether decorin expression is a prognostic factor in soft tissue tumors.

Methods

Decorin expression was examined in 85 samples obtained from 77 patients by real‐time quantitative PCR and immunohistochemistry.

Results

Lower levels of decorin were expressed in liposarcoma and malignant peripheral nerve sheath tumor than in lipoma (<0.01) and neurofibroma (P < 0.05), respectively. An immunohistochemical analysis for spindle‐cell sarcomas demonstrated decorin protein to be produced by myofibroblastic cells in the peripheral stromal extracellular spaces. On a Kaplan–Meier analysis, lower levels of decorin were associated with lower disease‐free and overall survival rates (P < 0.05) in 31 spindle‐cell sarcomas. A multivariate analysis revealed a significant correlation between a reduced decorin expression and a poor disease‐free survival (P = 0.04). In all seven patients with recurrent or metastatic lesions, the decorin expression levels were lower in secondary lesions than in primary lesions.

Conclusions

A reduced decorin expression was found to be a useful biomarker of aggressiveness in soft tissue tumor. J. Surg. Oncol. 2007;96:411–418. © 2007 Wiley‐Liss, Inc.
Feasibility of two multidimensional techniques, heart‐cut MDGC and GC×GC, for the separation of PCBs and PBDEs
Authors: Gómara Belén , Bordajandi Luisa R. , González María José
Published: June 2007

The feasibility of heart‐cut MDGC‐ECD and GC×GC‐μECD for the separation of polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) has been evaluated. Among the different column combinations tested, the best results were obtained when using either a DB‐5 type or an HT‐8 column as the first dimension combined with a mid‐polar stationary phase (50% phenyl) as the second dimension. The coelutions between the target PCBs and PBDEs in the first dimension were satisfactorily resolved once transferred to the second column. Repeatability and intermediate precision were satisfactory in both systems, considering retention times in both dimensions. Nevertheless, peak area/volume precision was better for heart‐cut MDGC since software for the data analysis in the case of GC×GC was still under development. The need for multiple injections of the same extract on the heart‐cut MDGC system was the main drawback since the analysis time it increased. GC×GC becomes then a valuable alternative able to achieve the same performance in one injection. However, the GC×GC data analysis is still very time‐consuming and needs further development. The applicability of both separation techniques was shown using a human breast milk sample with low concetrations of PCBs (0.2–227 pg/g fresh weight) and PBDEs (1.2–41 pg/g fresh weight).
Capillary electrophoresis of viruses, subviral particles and virus complexes
Authors: Kremser Leopold , Bilek Gerhard , Blaas Dieter , Kenndler Ernst
Published: June 2007

CZE and CIEF were so far applied to the analysis of tobacco mosaic virus, Semliki forest virus, human rhinovirus, adenovirus, norovirus and the bacteriophages T5 and MS2. The concentration of viral or subviral particles, of capsid proteins and viral genomes were determined, their electrophoretic mobilities and pI values were measured and bioaffinity reactions between viruses and antibodies, antibody fragments and receptor fragments were assessed. The role of detergents added to the BGE to obtain reproducible electrophoretic conditions was elucidated. The analytes were detected via their UV‐absorbance or via fluorescence after derivatization of the viral capsid, the nucleic acid, or both. A new dimension to the detection is added by the possibility of making use of the viral infectivity. At least in theory, this allows for the unequivocal identification of a single infectious virus particle after collection at the capillary outlet. This review summarizes the 25 papers so far published on this topic.
Making strategy real: Bringing people together toward a common cause
Authors: Beatty Katherine Colarelli , Quinn Laura
Published: June 2007

The hardest part of strategic leadership is getting people throughout the organization—from the executive team to the people on the front lines—to think and act similarly when making or carrying out strategy, even as the business environment continually places new demands on the organization. For leaders, closing the gap between strategy and execution requires focusing on clear priorities, creating common understanding through real dialogue, and engendering a learning orientation in the organization.
Toughening of Polylactide by Melt Blending with a Biodegradable Poly(ether)urethane Elastomer
Authors: Li Yongjin , Shimizu Hiroshi
Published: June 2007

Melt blending of polylactide (PLA) and a biodegradable poly(ether)urethane (PU) elastomer has been performed in an effort to toughen the polylactide without compromising its biodegradability and biocompatibility. The miscibility, phase morphology, mechanical properties, and toughening mechanism of the blend were investigated. The blend was found by dynamic mechanical analysis to be a partially miscible system with shifted glass transition temperatures. The PU elastomer was dispersed in the PLA matrix with a domain size of sub‐micrometer scale. The addition of PU elastomer not only accelerated the crystallization speed, but also decreased the crystallinity of the PLA. With an increase in PU content, the blend shows decreased tensile strength and modulus; however, the elongation at break and the impact strength were significantly increased, indicating the toughening effects of the PU elastomer on the PLA. The brittle fracture of neat PLA was gradually transformed into ductile fracture by the addition of PU elastomer. It was found that the PLA matrix demonstrates large area, plastic deformation (shear yielding) in the blend upon being subjected the tensile and impact tests, which is an important energy‐dissipation process and leads to a toughened, biodegradable polymer blend.

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Polyelectrolyte Complexes Based on (Quaternized) Poly[(2‐dimethylamino)ethyl methacrylate]: Behavior in Contact with Blood
Authors: Yancheva Elena , Paneva Dilyana , Danchev Dobri , Mespouille Laetitia , Dubois Philippe , Manolova Nevena , Rashkov Iliya
Published: June 2007

Polyelectrolyte complexes (PECs) between (quaternized) poly[2‐(dimethylamino)ethyl methacrylate] (PDMAEMA) and (crosslinked) N‐carboxyethylchitosan (CECh) or poly(2‐acrylamido‐2‐methylpropane sodium sulfonate) (PAMPSNa) were prepared and characterized in terms of their stability, equilibrium water content, and surface morphology. The evaluation of the behavior of the studied PECs in contact with blood revealed that the (crosslinked) CECh/(quaternized) PDMAEMA complexes had lost the inherent PDMAEMA cytotoxicity but still preserved haemostatic activity. In contrast, the complex formation between (quaternized) PDMAEMA and PAMPSNa allowed the preparation of materials with improved blood compatibility.

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Main‐Chain Liquid Crystalline Polymers Based on Bis‐Etherified 9,9‐Dihexyl‐2,7‐bis(4′‐hydroxy‐1,1′‐biphen‐4‐yl)fluorenes
Authors: Sović Tanja , Kappaun Stefan , Koppitz Andreas , Zojer Egbert , Saf Robert , Bartl Karin , Fodor‐Csorba Katalin , Vajda Aniko , Diele Siegmar , Pelzl Gerhard , Slugovc Christian , Stelzer Franz
Published: June 2007

A series of liquid crystalline compounds based on 2,7‐bis(biphenyl)fluorenes was synthesised by a Suzuki cross‐coupling reaction and subsequent etherification with different bromoalkenes. By simple variations of the chain lengths the temperature range in which the nematic mesophase is present could be tuned. The described approach offers the possibility of covalent incorporation of the mesogens into polymers via olefin metathesis techniques, resulting in enlarged stability of the mesophase. Monomers and polymers could be easily aligned on rubbed polyimide substrates as revealed by polarised absorption spectroscopy.

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Tailored Branched Polyolefins by Metallocene Catalysis
Authors: Kaminsky Walter , Hoff Matthias , Derlin Stefanie
Published: June 2007

Metallocene/methylaluminoxane catalysts are able to design copolymers with tailored architectures. It is possible to copolymerize ethene with higher α‐olefins and cyclic olefins. The terpolymer of ethene/1‐hexene/norbornene shows a better flexibility than the ethene/norbornene copolymer by a similar high transparency. The influence of the comonomer concentration on activity, molecular weight, and glass transition temperature is given as well as the comparison to 1‐hexene/norbornene and propene/norbornene copolymers. Hexene/norbornene copolymers were found to have a predominant alternating microstructure.

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Microwave‐Assisted Synthesis and Characterization of Poly(ε‐caprolactone)/Montmorillonite Nanocomposites
Authors: Liao Liqiong , Zhang Chao , Gong Shaoqin
Published: June 2007

Poly(ε‐caprolactone) (PCL)/montmorillonite (MMT) nanocomposites were prepared by in situ ring‐opening polymerization of ε‐caprolactone in the presence of MMT modified by hydroxyl‐group containing alkylammonium cation (Cloisite®30B) in a single mode microwave oven. For the polymerization mixtures, plateaus or exothermal peaks were observed in their temperature‐time profiles and can be attributed to the heat‐generating nature of the ring‐opening polymerization. The morphologies of the nanocomposites showed a predominantly exfoliated structure. The mechanical properties of the nanocomposites were evaluated via dynamic mechanical analysis. Compared with that of the recovered PCL matrix, the mechanical properties of the PCL/Cloisite®30B nanocomposites showed obvious improvement.

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Synthesis and Layer‐by‐Layer Deposition of Spherical Poly(3,4‐ethylenedioxythiophene) Nanoparticles ‐ Toward Fast Switching Times between Reduced and Oxidized States
Authors: Müller Kevin , Park Mi‐Kyoung , Klapper Markus , Knoll Wolfgang , Müllen Klaus
Published: June 2007

A microemulsion polymerization for the synthesis of poly(3,4‐ethylenedioxythiophene) (PEDOT) nanoparticles is described. Spherical and electrically conducting PEDOT particles with diameters as small as 27 ± 8 nm were obtained by using decyltrimethylammonium bromide as a cationic surfactant. PEDOT nanoparticle multilayers, alternated with poly(styrene sulfonate), were prepared by the layer‐by‐layer deposition technique. Electrochemical surface plasmon resonance experiments revealed a ten‐fold increase in the switching time between redox states as compared with Baytron P/poly(ethyleneimine) multilayers. The enhanced charge transport can be attributed to an improved diffusion of the charge‐balancing counterions into the PEDOT nanoparticles.

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