bluuebunny/crossref_metadata_2025_split huggingface dataset:
The combination of micron and nanotopography by H2SO4/H2O2 treatment and its effects on osteoblast‐specific gene expression of hMSCs
Authors: Mendonça Gustavo , Mendonça Daniela B. S. , Aragão Francisco J. L. , Cooper Lyndon F. 
Published: February 2010

AbstractH2SO4/H2O2 treatment of titanium implants imparts nanofeatures to the surface and alters the osteoblast response. The aim of this study was to evaluate the effect of H2SO4/H2O2 treatment of commercially pure Titanium (cpTi) surfaces on gene expression of human mesenchymal stem cells (hMSCs) differentiated into osteoblasts. Commercially pure grade IV titanium disks (20.0 mm × 1.0 mm) were polished or polished and subsequently treated by grit blasting or grit‐blasting/acid etching with an H2SO4/H2O2 solution. The surfaces were divided into three groups: smooth (S), grit‐blasted (Gb), and nanostructured: grit‐blasted/acid etched (Nano). Surfaces were examined by scanning electron microscopy and atomic force microscopy. HMSCs were grown on the disks. The data points analyzed were at 3, 7, 14, and 28 days. Real‐time PCR was used to measure the mRNA levels of ALP, BSP, Runx2, OCN, OPN, and OSX. The housekeeping gene GAPDH was used as a control. Descriptive statistics were calculated using Microsoft Excel. T‐test was performed for comparison of mRNA levels when compared with S surfaces (p < 0.05). All osteoblast‐specific genes were regulated in surface‐dependent patterns and most of them were upregulated on the Nano surfaces. Runx2 and OSX mRNAs were more than threefold upregulated at days 14 and 28 on Nano. Higher levels for ALP (38‐fold), BSP (76‐fold), and OCN (3‐fold) were also observed on the Nano surfaces. A grit‐blasted surface imparted with nanofeatures by H2SO4/H2O2 treatment affected adherent cell bone‐specific gene expression. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res, 2010
Matrix accumulation by articular chondrocytes during mechanical stimulation is influenced by integrin‐mediated cell spreading
Authors: Spiteri Caroline , Raizman Igal , Pilliar Robert M. , Kandel Rita A. 
Published: February 2010

AbstractWe have shown previously that cyclic compression of newly forming bioengineered cartilage in vitro results in improved tissue formation via changes in expression of matrix metalloproteases, such as, MT1‐MMP (membrane type metalloprotease), and increased synthesis of matrix molecules. Several studies have suggested an association between MT1‐MMP and integrins, which are known to influence cell shape. Thus, the objectives of this study were to determine the effect of compressive mechanical stimulation on cell shape and the role of integrins and MT1‐MMP in mediating these changes and influencing matrix accumulation. Bovine articular chondrocytes were grown on the surface of a porous ceramic substrate for 72 h and then cyclically compressed for 30 min. Scanning electron microscopy and morphometric analysis demonstrated that compression induced a rapid, transient increase in chondrocyte spreading by 10 min, followed by a retraction to prestimulated size within 6 h. This was associated with increased accumulation of newly synthesized proteoglycans, as determined by quantification of radioisotope incorporation. Blocking the α5β1 integrin, or its β1 subunit, inhibited cell spreading and resulted in a partial inhibition of compression‐induced increase in matrix accumulation. Knockdown of MT1‐MMP expression partially inhibited cell retraction and resulted in a reduced matrix accumulation as well. These results suggest that chondrocyte spreading and retraction following cyclic compression in vitro regulates matrix accumulation. Understanding the mechanisms that regulate chondrocyte mechanotransduction may ultimately lead to the design of improved repair tissue for cartilage damage. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res, 2010
Effect of pro‐inflammatory and immunoregulatory cytokines on human tenocytes
Authors: John Thilo , Lodka Dörte , Kohl Benjamin , Ertel Wolfgang , Jammrath Jennifer , Conrad Claudia , Stoll Christiane , Busch Catharina , Schulze‐Tanzil Gundula 
Published: February 2010

AbstractTendon injury induces a local inflammatory response, characterized by the induction of pro‐inflammatory cytokines. The aim of the present study was to analyze the effects of TNFα, IL‐6 and IL‐10 on key parameters of tendon homeostasis. Cultured primary human tenocytes were treated with the recombinant cytokines IL‐6, IL‐10, TNFα, or combinations of TNFα with IL‐6 and IL‐10 (10 ng/mL, 6, 24 h). Expression of type I collagen, elastin, MMP‐1, TNFα, IL‐1β, IL‐6, IL‐10, and suppressors of cytokine signaling (SOCS1, 3) was analyzed with the use of RTD‐PCR, immunocytochemistry, and Western blot analysis. In response to TNFα, tenocytes reduced their type I collagen deposition but increased their elastin gene expression and highly upregulated their expression for MMP‐1, pro‐inflammatory (TNFα, IL‐1β) and immunoregulatory (IL‐6, IL‐10) cytokines. TNFα stimulation augmented SOCS1, whereas SOCS3 expression in tenocytes was also induced by IL‐6. The treatment of tenocytes with IL‐6 and IL‐10 had no effect on cytokine expression. Neither IL‐6 nor IL‐10 modulated the observed effects of TNFα significantly. These results indicate that TNFα strongly activates the tenocytes to amplify their own TNFα expression and, subsequently, that of other regulatory cytokines and matrix degrading enzymes. However, the impact of IL‐6 and IL‐10 on tenocytes remains unclear. © 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 28:1071–1077, 2010
Prognostic factors in stage IB–IIB cervical adenocarcinoma patients treated with radical hysterectomy and pelvic lymphadenectomy
Authors: Kodama Junichi , Seki Noriko , Masahiro Satoko , Kusumoto Tomoyuki , Nakamura Keiichiro , Hongo Atsushi , Hiramatsu Yuji 
Published: February 2010

AbstractObjectivesThe purpose of the present study was to identify prognostic factors and patterns of recurrence in patients with stage IB–IIB cervical adenocarcinoma who had undergone radical surgery and to compare these patterns with those observed in squamous cell carcinoma (SCC) patients.MethodsWe retrospectively reviewed 303 patients (97 with adenocarcinoma and 206 with SCC) with stage IB–IIB cervical cancer who had undergone radical hysterectomy and pelvic lymphadenectomy.ResultsIn the case of the adenocarcinoma patients, lymph node metastasis and parametrial invasion were independent indicators of disease‐free survival, whereas lymph node metastasis was the only independent prognostic factor for the overall survival of the patients. The sites of recurrence did not significantly differ between the adenocarcinoma and SCC patients. In parametrium‐positive patients, adenocarcinoma was found to be an independent prognostic factor for disease‐free survival. In patients with positive pelvic lymph node, adenocarcinoma was found to be an independent prognostic factor for both disease‐free and overall survival.ConclusionsAdenocarcinoma was found to be an independent prognostic factor for survival in patients with positive pelvic node or parametrial extension. Furthermore, the patterns of recurrence did not differ significantly between the adenocarcinoma and SCC patients. J. Surg. Oncol. 2010; 101:413–417. © 2010 Wiley‐Liss, Inc.
Rapid screening and identification of the antioxidants in Hippocampus japonicus Kaup by HPLC‐ESI‐TOF/MS and on‐line ABTS free radical scavenging assay
Authors: Chen Junhui , Zhao Hengqiang , Shi Qian , Zhang Daolai , Cheng HongYan , Wang Xiaoru , Sen‐Chun Lee Frank 
Published: February 2010

AbstractIn this paper, a method based on HPLC coupled with ESI‐TOF/MS and on‐line to a stable free radical scavenging detection system has been developed to rapidly screen and identify the major antioxidants in the water extract of Hippocampus japonicus Kaup, a kind of marine medicinal organism. The developed on‐line stable free radical scavenging detection method of water extract from H. japonicus Kaup revealed the presence of three radical scavenging compounds, which were simultaneously identified as hypoxanthine, phenylalanine and tryptophane by high‐resolution TOF‐MS. To the best of our knowledge, it is original to demonstrate the rapid and successful use of HPLC‐ESI‐TOF/MS and on‐line 2,2′‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulfonate) diammonium salt free radical scavenging assay to directly and simultaneously screen and identify the antioxidants in the water extracts of H. japonicus Kaup without any purification. The present method provides a useful improvement on the reducing of workload and a powerful tool for rapid screening and identification of free radical scavenging compounds in complex natural products.
Screening of N‐nitrosamines in tap and swimming pool waters using fast gas chromatography
Authors: Jurado‐Sánchez Beatriz , Ballesteros Evaristo , Gallego Mercedes 
Published: February 2010

AbstractN‐Nitrosamines (NAms) are suspected human carcinogens that have been identified as drinking water and wastewater pollutants. In this work, a sensitive screening/confirmation method was proposed for the determination of the most toxic NAms that can be found in water samples (N‐nitrosodimethylamine, N‐nitrosodiethylamine, N‐nitrosodibutylamine, N‐nitrosomorpholine, N‐nitrosopiperidine, and N‐nitrosopyrrolidine). A sample volume of 250 mL was first preconcentrated in an automatic SPE unit and then the extract was concentrated to a final volume of 10 μL (providing a preconcentration factor of 25 000). Aliquots of the extract were subjected to a rapid screening process (1.6 min) by using a short capillary polar column (1.5 m length) and GC with nitrogen–phosphorous detection. In this way, the high number of samples to be tested routinely in a water laboratory is simplified due to a reduction in the analysis time. Thus, the screening method acts as a filter that indicates whether target analytes are present, above or below the cut‐off level (3.8 or 10.4 ng/L), giving no false negatives at concentrations below the guide values for NAms in drinking water established by different countries. Positive samples (tap and swimming pool waters) were then confirmed by GC‐MS detection.
Characterization of stationary phases for reversed‐phase chromatography
Authors: Molíková Martina , Jandera Pavel 
Published: February 2010

AbstractRetention characteristics of seven silica‐based chromatographic columns (Bidentate C18, Silica‐hydride, Spherisorb ODS‐1, Resolve C18, XTerra C18, XBridge Phenyl and Blaze C8 Polydentate) were compared. The columns differ in the character of the support, including silica type B, hydrosilated silica, and hybrid silica gel with incorporated methyl groups, or ethylene bridges; further in the type of chemically bonded stationary phase, including C18, C8 and phenyl ligands, endcapped and non‐endcapped with single point, bidentate and polydentate multi‐point attachment to the adsorbent surface. Special attention was focused on hydrophobic and polar selectivity, silanol activity and anion‐exclusion. The columns were compared and classified on the basis of the results of the classical column performance tests, retention of homologous n‐alkylbenzenes over a broad composition range of aqueous‐organic mobile phases and of naphthalene sulphonic acids in aqueous mobile phases without organic solvents.
Size exclusion chromatography – A blessing and a curse of science and technology of synthetic polymers
Authors: Berek Dušan 
Published: February 2010

AbstractSize exclusion chromatography, SEC is one of the most popular methods for the separation of different kinds of macromolecules. This critical review gives concise information about macromolecules and their behavior in solution, basic understanding about principles, instrumentation, and application possibilities of SEC, and more in detail discusses drawbacks and pitfalls of the method with the emphasis on synthetic polymers. Selected practical advices are included to help enhance the quality of SEC results.
Smoothed aggregation for Helmholtz problems
Authors: Olson Luke N. , Schroder Jacob B. 
Published: February 2010

AbstractWe outline a smoothed aggregation algebraic multigrid method for 1D and 2D scalar Helmholtz problems with exterior radiation boundary conditions. We consider standard 1D finite difference discretizations and 2D discontinuous Galerkin discretizations. The scalar Helmholtz problem is particularly difficult for algebraic multigrid solvers. Not only can the discrete operator be complex‐valued, indefinite, and non‐self‐adjoint, but it also allows for oscillatory error components that yield relatively small residuals. These oscillatory error components are not effectively handled by either standard relaxation or standard coarsening procedures. We address these difficulties through modifications of SA and by providing the SA setup phase with appropriate wave‐like near null‐space candidates. Much is known a priori about the character of the near null‐space, and our method uses this knowledge in an adaptive fashion to find appropriate candidate vectors. Our results for GMRES preconditioned with the proposed SA method exhibit consistent performance for fixed points‐per‐wavelength and decreasing mesh size. Copyright © 2010 John Wiley & Sons, Ltd.
Convergence of adaptive edge finite element methods for H(curl)‐elliptic problems
Authors: Zhong Liuqiang , Shu Shi , Chen Long , Xu Jinchao 
Published: February 2010

AbstractThe standard adaptive edge finite element method (AEFEM), using first/second family Nédélec edge elements with any order, for the three‐dimensional H(curl)‐elliptic problems with variable coefficients is shown to be convergent for the sum of the energy error and the scaled error estimator. The special treatment of the data oscillation and the interior node property are removed from the proof. Numerical experiments indicate that the adaptive meshes and the associated numerical complexity are quasi‐optimal. Copyright © 2010 John Wiley & Sons, Ltd.
An algebraic generalization of local Fourier analysis for grid transfer operators in multigrid based on Toeplitz matrices
Authors: Donatelli M. 
Published: February 2010

AbstractLocal Fourier analysis (LFA) is a classical tool for proving convergence theorems for multigrid methods (MGMs). In particular, we are interested in optimal convergence, i.e. convergence rates that are independent of the problem size. For elliptic partial differential equations (PDEs), a well‐known optimality result requires that the sum of the orders of the grid transfer operators is not lower than the order of the PDE approximated. Analogously, when dealing with MGMs for Toeplitz matrices, a well‐known optimality condition concerns the position and the order of the zeros of the symbols of the grid transfer operators. In this work we show that in the case of elliptic PDEs with constant coefficients, the two different approaches lead to an equivalent condition. We argue that the analysis for Toeplitz matrices is an algebraic generalization of the LFA, which allows to deal not only with differential problems but also for instance with integral problems. The equivalence of the two approaches gives the possibility of using grid transfer operators with different orders also for MGMs for Toeplitz matrices. We give also a class of grid transfer operators related to the B‐spline's refinement equation and study their geometric properties. Numerical experiments confirm the correctness of the proposed analysis. Copyright © 2010 John Wiley & Sons, Ltd.
Considerations for contractile electroactive polymeric materials and actuators
Authors: Rasmussen Lenore , Erickson Carl J , Meixler Lewis D , Ascione George , Gentile Charles A , Tilson Carl , Abelev Esta 
Published: February 2010

AbstractRas Labs produces electroactive polymer (EAP)‐based materials and actuators that bend, swell, ripple and now contract (new development) with low electric input. This is an important attribute because of the ability of contraction to produce life‐like motion. The mechanism of contraction is not well understood. Radionuclide‐labeled experiments were conducted to follow the movement of electrolytes and water in these EAPs when activated. Extreme temperature experiments were performed on the contractile EAPs with very favorable results. One of the biggest challenges in developing these actuators, however, is the electrode‐EAP interface because of the pronounced movement of the EAP. Plasma treatments of metallic electrodes were investigated in order to improve the attachment of the embedded electrodes to the EAP material. Surface analysis, adhesive testing and mechanical testing were performed to test metal surfaces and metal–polymer interfaces. Nitrogen plasma treatment of titanium produced a strong metal–polymer interface; however, oxygen plasma treatment of both stainless steel and titanium produced even stronger metal–polymer interfaces. Plasma treatment of the electrodes allows for the embedded electrodes and the EAP material of the actuator to work and move as a unit, with no detachment, by significantly improving the metal–polymer interface. Copyright © 2010 Society of Chemical Industry
Dielectric electro‐active polymer push actuators: performance and challenges
Authors: Benslimane Mohamed Y , Kiil Hans‐Erik , Tryson Michael J 
Published: February 2010

AbstractProgress in research and development in the field of electro‐active polymers has enabled prototype fabrication, which demonstrates the future potential and versatility offered by this technology. These prototypes can be qualified as laboratory demonstrators. A new design of dielectric elastomer linear actuators is presented here. These actuators have the unique properties of being self‐supporting and core‐free. They are capable of large push forces and are fabricated based on large‐scale industrial manufacturing processes. Actuators can be easily scaled to fit specific application needs. Actuator design and construction principles, as well as modelling are presented and discussed for push InLastor® actuators. The actuators exhibit modest strokes and high actuation forces. Current design considerations indicate that the achievable force output is reduced by about 40% due to the passive ends of the actuator. Dielectric electro‐active polymer DEAP film manufacturing challenges contribute to reducing the achievable breakdown strength to 35 V µm−1 and limit the strain to modest figures. It is shown that push InLastor actuators can be operated at field strength levels above 45 V µm−1, and exhibit larger strokes and forces in good agreement with the model. At these elevated electric field levels, risks of catastrophic breakdown increase, resulting in reduced actuator lifetime. A major milestone in the manufacturing of actuators based on the DEAP technology has been achieved by Danfoss PolyPower. Large‐scale manufacturing of robust and reliable push tubular actuators is possible. Roll‐to‐roll manufacturing processes make it possible to manufacture these powerful actuators, based on PolyPower compliant electrode design. Copyright © 2010 Society of Chemical Industry
Copolymerization of ethylene and in situ‐generated α‐olefins to high‐performance linear low‐density polyethylene with a two‐catalyst system supported on mesoporous molecular sieves
Authors: Guo Cun‐Yue , Xu Hao , Zhang Mingge , Yang Hai‐Jian , Yan Fengwen , Yuan Guoqing 
Published: February 2010

AbstractThe manufacture of linear low‐density polyethylene (LLDPE) is of great significance in academia and industry. The employment of a single monomer, i.e. ethylene, to produce LLDPE by introducing two catalysts into one reactor to conduct ethylene copolymerization with in situ‐generated α‐olefins has proved to be an effective way in this case. Moreover, immobilization of catalysts affords LLDPE with better morphology and improved physical properties. An iron‐based diimine complex immobilized on methylaluminoxane (MAO)‐treated mesoporous molecular sieves was used to oligomerize ethylene to α‐olefins with improved selectivity to lower molar mass fractions. Based on this, zirconocene compound was also supported on mesoporous molecular sieves to comprise a two‐catalyst system to produce LLDPE from a single ethylene monomer. Copolymerization performed at both atmospheric and high pressure produced LLDPE of high molecular weight and broad molecular weight distribution without using MAO during the polymerization processes. Physical and mechanical measurements evidenced significant increases in tensile strength, tensile modulus and Izod impact strength. A marked shear‐thinning phenomenon and improved storage modulus of LLDPE produced using catalysts supported on MCM‐41 and SBA‐15 mesoporous molecular sieves indicated a stronger interfacial interaction between the molecular sieve support and the polymeric matrix. Copyright © 2010 Society of Chemical Industry
Hopping transport at localized band tail states in amorphous hydrogenated silicon
Authors: Murayama Kazuro , Nomura Yukio , Fujisaki Tatsuya 
Published: February 2010

AbstractThe transient current of the time‐of‐flight (TOF) in amorphous hydrogenated silicon calculated from the hopping at localized band tail states with the Monte Carlo simulation is shown to agree with that of the experiment in the line shape and the transit time. The attempt‐to‐escape frequencies obtained by fitting the electric field dependence of the transit time in the simulation with the Pfister–Ohno equation for the transit time derived from the hopping model, have been far beyond the phonon frequencies as in the case of the experiment. The attempt‐to‐escape frequency has been empirically described with the Meyer–Neldel (MN) rule as well as in the experiment. The MN rule for the attempt‐to‐escape frequency in the TOF has been concluded to originate in the hopping controlled by the deep localized band tail states from the simulation.
Self‐organized growth of ZnO‐based nano‐ and microstructures
Authors: Lorenz Michael , Rahm Andreas , Cao Bingqiang , Zúñiga‐Pérez Jesús , Kaidashev Evgeni M. , Zhakarov Nikolai , Wagner Gerald , Nobis Thomas , Czekalla Christian , Zimmermann Gregor , Grundmann Marius 
Published: February 2010

AbstractZnO‐based nano‐ and micro‐structures with controlled orientation, size, and lateral density were grown by specially designed two‐step pulsed laser deposition and direct carbothermal growth, respectively. Different substrate orientations and nucleation layers allow well‐defined tuning of growth direction and lateral arrangement of the wires. As a result, axial MgZnOZnO nano quantum dots and homogeneous radial nano core‐shell quantum well structures are demonstrated. Donor and acceptor doping of nano‐ and microwires influence considerably both electrical characteristics as well as morphology including branching. Field effect transistors with n‐ and p‐type wire channel and nanowire p–n junctions seem to prove a reproducible p‐type conductivity of phosphorous‐doped ZnO wires. Single ZnO wire (309 nm thick, 3.99 µm high) grown on pyramidal base with controlled lateral density by tuning the ZnO template layer in a two‐step PLD process.magnified image