bluuebunny/crossref_metadata_2025 huggingface dataset:
A data hiding method without specifying embedded positions for JPEG image
Authors: Seki Yusuke , Kobayashi Hiroyuki , Fujiyoshi Masaaki , Kiya Hitoshi
Published: May 2007

In this paper the authors propose a data hiding method for JPEG images that has a degree of freedom in selecting the hiding position and does not require a reference image or knowledge of the hiding position during extraction. In conventional methods, the position for the transform coefficients which hide the data must be specified beforehand, and that position must be known during extraction. The proposed method does not require specifying the hiding position beforehand and offers some freedom in selecting the hiding position. Therefore, a hiding position that is appropriate can be selected for each image and block to be subjected to JPEG encoding. Given this, the proposed method can reduce image degradation and improve compression efficiency compared to the conventional methods. Moreover, because knowledge of the hiding position is not required during extraction, information management is thus simpler during extraction. The effectiveness of the proposed method is confirmed through simulations. © 2007 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 90(11): 21–30, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.20356
A new initial‐rotor‐position estimation method for SPM synchronous motors using spatially rotating high‐frequency voltage: A dynamic simulator approach taking flux saturation phenomena into account
Authors: Shinnaka Shinji , Kumakura Takeshi
Published: May 2007

First, this paper proposes a new dynamic mathematical model of surface‐mounted permanent magnet synchronous motors (SPMSMs) with flux saturation phenomena, in a stationary reference frame. Second, based on the dynamic model, this paper establishes new dynamic simulators taking flux saturation phenomena into account, which act as very powerful tools for developing initial‐rotor‐position estimation methods for SPMSMs. Third, this paper proposes a new initial‐rotor‐position estimation method for SPMSMs. The proposed method is so simple that it inputs a spatially rotating high‐frequency voltage to SPMSMs, measures current output, and can estimate directly rotor position of N‐pole through norm evaluation of the current. The method exploits flux saturation phenomena inherent to SPMSMs and is insensitive to all motor parameters. According to experiments, the maximum estimation error is about ±0.035 rad (±2○) in terms of mechanical angle, which is comparable to sensor mounting error and is sufficiently small for initial drive of SPMSMs. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 160(3): 63–73, 2007; Published online in Wiley InterScience (www.interscience. wiley.com). DOI 10.1002/eej.20241
Three‐dimensional numerical analysis of a liquid metal MHD generator
Authors: Yamada Katsunori , Maeda Tetsuhiko , Hasegawa Yasuo , Okuno Yoshihiro
Published: May 2007

Three‐dimensional numerical analysis of a liquid metal MHD generator has been carried out. The three‐dimensional structures of the electromagnetic field and fluid flow in the MHD generator have been clarified, and the effect of the electrode width on the performance has also been examined, taking account of the current flow in the electrode. Structures of the electromagnetic field and fluid flow are complicated owing to the three‐dimensional current flow, induced magnetic field, and Lorentz force. The highest performance is found to be obtained when the width of the electrode is equal to that of the generator. The performance predicted from three‐dimensional analysis is somewhat lower than that from two‐dimensional analysis because of the larger input power. The increase in the input power is attributed to the increase in Lorentz force caused by less reduced magnetic flux density and to the additional friction loss on the insulator walls (x−y plane). © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 160(3): 19–26, 2007; Published online in Wiley InterScience (www. interscience.wiley.com). DOI 10.1002/eej.20282
Power factor correction using magnetic energy recovery current switches
Authors: Takaku Taku , Isobe Takanori , Narushima Jun , Tsutsui Hiroaki , Shimada Ryuichi
Published: May 2007

In this paper, we propose a Magnetic Energy Recovery Switch (MERS). The switch consists of four MOSFET elements and one capacitor. A power factor improvement is automatically possible regardless of the impedance and power frequency of the load by synchronized switching of MERS with a power supply. MERS itself generates voltage and compensates for the inductance voltage unlike a conventional series capacitor, so that another DC power supply is not needed. An experiment was carried out to demonstrate the automatic correction of the power factor. We can also expect energy saving of electromachines such as an electric motor by the power factor correction with MERS. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 160(3): 56–62, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20321
A practical study of the 66‐kV fault current limiter (FCL) system with rectifier
Authors: Tokuda Noriaki , Matsubara Yoshio , Yuguchi Kyosuke , Ohkuma Takeshi , Hobara Natsuro , Takahashi Yoshihisa
Published: May 2007

A fault current limiter (FCL) is extensively expected to suppress fault current, particularly required for a trunk power system's heavily connected high‐voltage transmission lines, such as the 500‐kV‐class power system which constitutes the nucleus of the electric power system. By installing such FCL in the power system, system interconnection is possible without the need to raise the capacity of the circuit breakers, and facilities can be configured for efficiency, among other benefits. For these reasons, fault current limiters based on various principles of operation have been developed both in Japan and abroad.

In this paper, we have proposed a new type of FCL system, consisting of solid‐state diodes, DC coil, and bypass AC coil, and described specifications of the distribution power system and 66‐kV model at the island power system and the superconducting cable power system. Also we have made a practical study of the 66‐kV class, the testing items and the future subjects of the rectifier‐type FCL system. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 160(3): 12–18, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20331
Stability estimation of SVCs in distribution systems
Authors: Shimizu Keiichi , Genji Takamu , Nakazawa Chikashi , Nakanishi Yosuke
Published: May 2007

This paper discusses the stability and an interactive phenomenon of one SVC, two or more sets of SVC, an SVC and an SVR in distribution systems. In particular, we focus on the saddle‐node bifurcation and Hopf bifurcation points. The two local bifurcation points show a boundary of a stable domain. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 160(3): 1–11, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20333
A matching transformer‐less inrush current suppressor for transformers using a series‐connected small‐rated voltage‐source PWM converter—consideration of the control gains and required ratings of the PWM converter
Authors: Yamada Hiroaki , Tanaka Toshihiko , Funabiki Shigeyuki
Published: May 2007

This paper proposes a new inrush current suppressor using a series‐connected small‐rated PWM converter for a transformer. The PWM converter is directly connected in series between the source and transformer without a matching transformer. The inrush phenomena of the matching transformer, thus, can be avoided. The control gain and required ratings of the series‐connected small‐rated PWM converter are discussed in detail. The capacity of the DC capacitor of the PWM converter is also discussed considering the active power flows into the PWM converter. The PSCAD/EMTDC is used to verify the validity of the proposed inrush current suppressor. A prototype experimental model is constructed and tested. The experimental results demonstrate that the proposed suppressor can perfectly overcome the inrush phenomena of transformers. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 160(3): 45–55, 2007; Published online in Wiley InterScience (www. interscience.wiley.com). DOI 10.1002/eej.20374
Gigabit Ethernet‐based time transfer system
Authors: Hisadome Kenji , Kihara Masami
Published: May 2007

We suggest a gigibit Ethernet (GbE)‐based time transfer technique. In this technique, timing signals used for clock error measurements are inserted into interframe gaps and transmitted. We developed the GbE‐based time transfer system and evaluated the phase stability and precision. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 160(3): 39–44, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20383
Algorithm for detecting frequencies in multi‐sine signals by inductive generation
Authors: Kubo Kazuyoshi
Published: May 2007

Prony's method is an approximation approach to decomposing a function into sum of exponents and thus is applicable to unknown frequencies estimation of signals. The concrete algorithms for estimating pure sine wave, triple tone, and quadruple tone have already been derived and presented. This paper aims at deriving the estimating algorithm for multi‐sine signals which consist of unknown sine waves.
The new method of generating an algebraic algorithm for detecting unknown frequencies in the signals is derived by mathematical induction. The crux of the generation is dependent on the integer matrices induction. A handy method for generating the matrices is shown as well. Algorithms for the triple tone, quadruple tone, and the higher‐order tone are generated and verified. As a result, they are shown to be identical to the ordinary algorithms.
Subjects on the application of the induced algorithm to practical frequency detection are discussed. The algorithm has both instantaneity in the time domain and higher resolution in the frequency domain, that is, the signal analysis by the algorithm can be performed without constraint of the uncertainty principle. An iterative solution for algebraic equation is dominant for calculation in the algorithm. Techniques for detecting frequencies in a multi‐sine of unknown order are also discussed. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 160(3): 27– 38, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20404
The effect of arm crossing on persistence and performance
Authors: Friedman Ron , Elliot Andrew J.
Published: May 2007

Two experiments investigated the hypothesis that arm crossing serves as a proprioceptive cue for perseverance within achievement settings. Experiment 1 found that inducing participants to cross their arms led to greater persistence on an unsolvable anagram. Experiment 2 revealed that arm crossing led to better performance on solvable anagrams, and that this effect was mediated by greater persistence. No differences in comfort, instruction adherence, or mood were observed between the arms crossed and control conditions, and participants appeared to be unaware of the effect of arm crossing on their behavior. Implications of the findings are discussed in terms of the interplay between proprioceptive cues and contextual meaning. Copyright © 2007 John Wiley & Sons, Ltd.
Scanning Electrochemical Microscopy (SECM) Based Detection of Oligonucleotide Hybridization and Simultaneous Determination of the Surface Concentration of Immobilized Oligonucleotides on Gold
Authors: Nunes Kirchner Carolina , Szunerits Sabine , Wittstock Gunther
Published: May 2007

The direct mode of scanning electrochemical microscopy (SECM) was used for the local deposition of oligonucleotide (ODN) patterns on thin gold films and the generation‐collection (GC) mode was applied for the determining the amount of surface‐accessible oligonucleotides. The local deposition was achieved through the micrometer‐sized formation of a conducting polymer bearing 15mer single‐stranded oligonucleotide strands. After the interaction of the oligonucleotide with its biotin‐labeled complimentary strand, streptavidin was bound. The molecular assembly was completed by linking biotin‐labeled β‐galactosidase from Escherichia coli to the streptavidin. The activity of the linked β‐galactosidase was mapped with SECM in the GC mode by monitoring the oxidation of p‐aminophenol (PAP) formed in the enzyme‐catalyzed hydrolysis of p‐aminophenyl‐β‐D‐galactopyranoside. The feedback effect due to recycling of the reaction product at the gold surface was analyzed. It was shown experimentally that this effect becomes insignificant at ultramicroelectrode (UME)‐substrate distances larger than 3 UME radii. The flux of formed PAP allowed the determination the surface density of accessible oligonucleotide strands in the functionalized polymer. It was shown that that thicker pyrrole/ODN–Pyrrole polymer films do not lead to a significantly increased accessible ODN surface concentration.
Towards error‐free hybrid simulation using mixed variables
Authors: Elkhoraibi Tarek , Mosalam Khalid M.
Published: May 2007

Two procedures are developed and implemented in a hybrid simulation system (HSS) with the aim of enhancing the accuracy and reliability of the online, i.e. pseudo‐dynamic, test results. The first procedure aims at correcting the experimental systematic error in executing the displacement command signal. The error is calculated as the difference between command and feedback signals and correlated to the actuator velocity using the least‐squares method. A feed‐forward error compensation scheme is devised leading to a more accurate execution of the test. The second procedure employs mixed variables with mode switching between displacement and force controls. The newly derived force control algorithm is evaluated using a parametric study to assess its stability and accuracy. The implementation of the mixed variables procedure is designed to adopt force control for high stiffness states of the structural response and displacement control otherwise, where the resolution of the involved instruments may favour this type of mixed control. A simple pseudo‐dynamic experiment of steel cantilever members is used to validate the HSS. Moreover, two experiments as application examples for the two developed procedures are presented. The two experiments focus on the seismic response of (a) timber shear walls and (b) reinforced concrete frames with and without unreinforced masonry infill wall. Copyright © 2007 John Wiley & Sons, Ltd.
Heat transfer and pressure loss characteristics of a heat exchanger for recovering latent heat (effects of straight fin length and fin pitch on the heat transfer and pressure loss characteristics)
Authors: Kawaguchi Kiyoshi , Okui Kenichi , Shimoura Takahiro , Ohkouchi Takaki , Osakabe Hiroyuki , Ninagawa Tosihide
Published: May 2007

In recent years, the requirement for the reduction of energy consumption has been increasing to solve the problems of global warming and the shortage of petroleum resources. A latent heat recovery type heat exchanger is one of the effective methods for improving thermal efficiency by recovering latent heat. This paper describes the heat transfer and pressure loss characteristics of a latent heat recovery type heat exchanger having straight fins (fin length: 65 mm or 100 mm, fin pitch: 2.5 mm or 4 mm). These were clarified by measuring the exchange heat quantity, the pressure loss of the heat exchanger, and the heat transfer coefficient between the outer fin surface and gas. The effects of fin length and fin pitch on heat transfer and pressure loss characteristics were clarified. Furthermore, equations for predicting the heat transfer coefficient and pressure loss which are necessary for heat exchanger design were proposed. ©2007 Wiley Periodicals, Inc. Heat Trans Asian Res, 36(4): 230– 247, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.20153 Copyright © 2004 Wiley Periodicals, Inc.
The heat transfer and pressure loss characteristics of a heat exchanger for recovering latent heat (the heat transfer and pressure loss characteristics of the heat exchanger with wing fin)
Authors: Kawaguchi Kiyoshi , Okui Kenichi , Shimoura Takahiro , Ohkouchi Takaki , Osakabe Hiroyuki , Ninagawa Tosihide
Published: May 2007

In recent years the requirement for reduction of energy consumption has been increasing to solve the problems of global warming and the shortage of petroleum resources. A latent heat recovery type heat exchanger is one of the effective methods of improving thermal efficiency by recovering latent heat. This paper described the heat transfer and pressure loss characteristics of a latent heat recovery type heat exchanger having a wing fin (fin pitch: 4 mm, fin length: 65 mm). These were clarified by measuring the exchange heat quantity, the pressure loss of heat exchanger, and the heat transfer coefficient between outer fin surface and gas. The effects of condensate behavior in the fins on heat transfer and pressure loss characteristics were clarified. Furthermore, the equations for predicting the heat transfer coefficient and pressure loss which are necessary in the design of the heat exchanger were proposed. ©2007 Wiley Periodicals, Inc. Heat Trans Asian Res, 36(4): 215–229, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.20154
Micro‐CT scanning analysis for inner structure of porous media
Authors: Yang Zhang , Xiaofeng Peng
Published: May 2007

A micro‐CT scanner was employed to investigate inner characteristics of porous media, and particular cakes were taken as samples. By obtaining the inner pore structure and inner structure reconstruction, porosity and its variation in the samples, water distribution in pores, and other inner characteristics were determined and explored. When the sample was dried after immersion in water, the solid frame shrank, some pores became larger and the porosity increased, while the sample not immersed in water did not change much after being dried. The experiments indicate that micro‐CT scanning is an effective technology to study the inner structure of porous materials with pores larger than tens of microns and also can be used to explore some important transport performance. ©2007 Wiley Periodicals, Inc. Heat Trans Asian Res, 36(4): 208– 214, 2007; Published online in Wiley InterScience (www.interscience. wiley.com). DOI 10.1002/htj.20155 Copyright © 2004 Wiley Periodicals, Inc.
Investigation of water migration in porous material using micro‐CT during wetting
Authors: Wu D. , Peng X.F.
Published: May 2007

A series of experiments were conducted to observe water transport in wood during wetting using a micro‐CT combined with scanning, reconstruction, and grey analysis technology. A comprehensive discussion was conducted to explore the characteristics of water transport and moisture distribution caused by local pore structure and properties in the wood sample during wetting. For wetting course of the wood immersed in water, water transport exhibits three stages. At the beginning, the dense region of the wood was wetted and contained some water which was unable to transfer into the sparse region because of the larger capillary force induced by the dense structure. Secondly, as water penetrates the wood, the sparse region contained much more water than the dense region. At this stage, the dense region is unsaturated. Finally, water transfers into both dense and sparse regions and gradually saturates them. ©2007 Wiley Periodicals, Inc. Heat Trans Asian Res, 36(4): 198–207, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.20156
Effect of curvature on thermocapillary‐buoyancy convection in a shallow annular pool
Authors: Shang Qi‐Wei , Liu Ying‐Jie , Li You‐Rong
Published: May 2007

In order to understand the influence of curvature on thermocapillary‐buoyancy convection in a differentially heated annular pool with an outer heated cylinder ($ro=40 mm$) and an inner cooled cylinder (ri=20 or 10 mm), a series of unsteady two‐dimensional numerical simulations using the finite‐volume method was conducted. The pool was filled with 0.65 cSt silicone oil (Prandtl number Pr=6.7); its depth changed from 0.5 to 1.5 mm. Simulation results show that the flows with different curvature are all stable at small temperature differences. Increasing the temperature difference, the flow transition to an oscillatory flows occurs. The critical temperature difference, depending on the curvature of annulus, is determined. It was found that there is a good agreement between the simulation and the experiment results on the critical temperature difference. ©2007 Wiley Periodicals, Inc. Heat Trans Asian Res, 36(4): 187– 197, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.20157
Joining characteristics of orthodontic wires with laser welding
Authors: Iijima Masahiro , Brantley William A. , Yuasa Toshihiro , Muguruma Takeshi , Kawashima Isao , Mizoguchi Itaru
Published: May 2007

Laser welding 0.016 × 0.022 in. β‐Ti, Ni–Ti, and Co–Cr–Ni orthodontic wires was investigated by measuring joint tensile strength, measuring laser penetration depth, determining metallurgical phases using micro X‐ray diffraction (micro‐XRD), and examining microstructures with an scanning electron microscope (SEM). Welding was performed from 150 to 230 V. Mean tensile strength for Ni–Ti groups was significantly lower (p < 0.05) than for most other groups of laser‐welded specimens. Although mean tensile strength for β‐Ti and Co–Cr–Ni was significantly lower than for control specimens joined by silver soldering, it was sufficient for clinical use. The β‐Ti orthodontic wire showed deeper penetration depth from laser welding than the Ni–Ti and Co–Cr–Ni orthodontic wires. Micro‐XRD patterns of laser‐welded β‐Ti and Ni–Ti obtained 2 mm from the boundary were similar to as‐received specimens, indicating that original microstructures were maintained. When output voltages of 190 V and higher were used, most peaks from joint areas disappeared or were much weaker, perhaps because of a directional solidification effect, evidenced by SEM observation of fine striations in welded β‐Ti. Laser welding β‐Ti and Co–Cr–Ni wires may be acceptable clinically, since joints had sufficient strength and metallurgical phases in the original wires were not greatly altered. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 2008
Preparation and characterization of novel hybrid of chitosan‐g‐PDMS and sodium montmorrilonite
Authors: Depan Dilip , Kumar Bijandra , Singh Raj Pal
Published: May 2007

Preparation and properties of Chitosan (CS)‐clay nanocomposites grafted with polydimethyl siloxane (PDMS) with different clay ratios are herein discussed. CS is intercalated into sodium montmorrilonite and PDMS is grafted onto CS under UV irradiation. Sample films of CS intercalated into clay and grafted with PDMS were prepared by solvent casting method with varying amount of nanoclay and PDMS. They were characterized by conventional techniques such as X‐ray diffractometry, fourier transform infrared spectroscopy, 13C NMR, thermo gravimetric analysis, and differential thermal analysis. Sorption behavior of samples has been followed by measuring swelling degree and issues on the interactions of biopolymers with clay are also discussed. The water absorption of composites films reduces with an increase in the amount of incorporated clay. This is due to the barrier formation in the form of cross‐linking points, which prevents water permeation into CS. The amount of adsorbed water is more, when the amount of CS exceeds the amount of PDMS. This shows high water retention capacity of CS. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 2008
Enhanced osteolytic potential of monocytes/macrophages derived from bone marrow after particle stimulation
Authors: Tamaki Yasunobu , Sasaki Kan , Sasaki Akiko , Takakubo Yuya , Hasegawa Hiroshi , Ogino Toshihiko , Konttinen Yrjö T. , Salo Jari , Takagi Michiaki
Published: May 2007

Background: Total hip replacement can be complicated by periprosthetic osteolysis. Monocytes/macrophages play a major role in the formation of the foreign body granulomas induced by wear debris. We hypothesized that periprosthetic monocytes/macrophages do not only accelerate inflammatory and osteoclast‐mediated osteolytic processes, but also resorb periprosthetic bone directly by themselves. This study was designed to evaluate the osteolytic potential in vitro of monocytes/macrophages derived from bone marrow. Methods: Monocytes/macrophages were produced by filtration of rat bone marrow cells, followed by culture in the presence of macrophage‐colony stimulating factor (M‐CSF). Monocyte/macrophage properties were ascertained using immunocytochemistry and phagocytic activity. Osteolytic cytokines and extracellular matrix degrading proteinases were quantified at the mRNA level. Results: Adherent cell fraction was immunoreactive for the monocyte/macrophage specific marker CD68 and active in the phagocytosis of carbon particles up to 72 h. They also showed immunoreactivity to cathepsin K, IL‐1β, IL‐6, and M‐CSF, but mostly did not react to TRAP. mRNA levels of osteolytic cytokines and extracellular matrix degrading proteinases were enhanced, but that of RANKL were not. Monocytes/macrophages resorbed dentine discs and carbonated calcium phosphate was very actively resorbed after stimulation with titanium particles. Discussion: Harvested bone marrow cells expressed monocyte/macrophage phenotype, but not osteoclastic markers. The capacity of these cathepsin‐K–positive phagocytic cells to resorb dentine discs and carbonated calcium phosphate in vitro suggests a direct role of monocytes/macrophages in bone resorption and periprosthetic osteolysis. The finding supports our hypothesis and previous histomorphometric observations on the presence of such osteolytic macrophages in vivo around loosening prosthesis. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 2008
Oxidation of proteins adsorbed on hemodialysis membranes and model materials
Authors: Caillou Samuel , Boonaert Christophe J. P. , Dewez Jean‐Luc , Rouxhet Paul G.
Published: May 2007

The cleaning of cellulosic hemodialysis membrane Cuprophan and model materials (glass; polystyrene and polypropylene, as such and surface‐oxidized), conditioned by adsorption of blood plasma proteins (HSA, fibrinogen, IgG) was investigated in vitro. Sodium hypochlorite (NaClO) and Renalin, a product containing hydrogen peroxide and peroxyacetic acid, were used as cleaning reagents. X‐ray photoelectron spectroscopy and the use of radiolabeled fibrinogen demonstrated the presence of varying amounts of a polypeptidic residue, with sulfur brought to a high oxidation stage (sulfonate‐like). The trends were the same for the three proteins regarding the effectiveness of the oxidizer and the influence of the surface properties. NaClO was much more effective than Renalin to remove the adsorbed proteins. The proteins adsorbed on Cuprophan were more sensitive to the oxidizers, when compared with proteins adsorbed on other materials. This may be due to both the lower protein–surface affinity, as indicated by radiochemical measurements, and the sensitivity of the material itself to the oxidizer, as revealed by weight loss measurements. These results support the attribution of hemocompatibility improvement after regeneration of Cuprophan with Renalin to the masking of the activating surface by a residue from previously adsorbed proteins. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 2008
Human osteoblast‐like cells response to nanofunctionalized surfaces for tissue engineering
Authors: Soumetz Federico Caneva , Pastorino Laura , Ruggiero Carmelina
Published: May 2007

Cells are sensitive both to the micro/nanotopographic and chemical features of their surrounding environment. The engineering of the surface properties of biomaterials is then critical to develop bioactive devices with which to elicit appropriate cellular responses. To this regard, the layer by layer (LBL) self assembly technique represents a simple and versatile method to modify surface properties by the deposition of ultrathin films with specific and predetermined properties. In this work biomimetic coatings containing fibronectin, an adhesive glycoprotein of the extracellular matrix, were assembled by means of the LBL technique, and tested for the growth of MG63 human osteoblast‐like cells, in order to evaluate their potential for the treatment of materials employed in bone‐tissue engineering. As a first step the assembly process was optimized by quartz crystal microbalance measurements and subsequently was repeated on nickel/titanium, silicon and glass samples. The results obtained from the investigation of cell response to the modified surfaces, put in evidence that the deposited nanostructured ultrathin films are effective in promoting cell proliferation. Our results show the high potential of the developed bioactive coatings for the engineering of biomimetic implants and for the optimization of their integration with the surrounding tissues. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 2008
Effect of serum metabolites of Pueraria lobata in rats on peripheral nerve regeneration: In vitro and in vivo studies
Authors: Chen Hsien‐Tung , Yao Chun‐Hsu , Chao Pei‐Dawn Lee , Hou Yu‐Chi , Chiang Hsiu‐Mei , Hsieh Chang‐Chi , Ke Cherng‐Jyh , Chen Yueh‐Sheng
Published: May 2007

This study provides in vitro and in vivo evaluation of rat serum metabolites of the Pueraria lobata (SMP) on peripheral nerve regeneration. In the in vitro study, we found that the SMP caused a marked enhancement of the nerve growth factor (NGF)‐mediated neurite outgrowth and the expression of synapsin I from PC12 cells. In the in vivo study, silicone rubber chambers filled with the SMP were used to bridge a 10‐mm sciatic nerve defect in rats. At the conclusion of 8 weeks, animals from the groups treated with the SMP had a relatively more mature structure with larger mean values of myelinated axon number, endoneurial area, and total nerve area when compared with those in the controls receiving the saline only. These results suggest that the serum metabolites of Pueraria lobata can be a potential nerve growth‐promoting factor. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 2008
Multiple roles of M‐CSF in human osteoclastogenesis
Authors: Hodge Jason M. , Kirkland Mark A. , Nicholson Geoffrey C.
Published: May 2007

Although the critical role of M‐CSF in osteoclastogenesis is well documented, there has been no detailed analysis of how it regulates human osteoclast formation and function in vitro. We used a human osteoclastogenesis model employing CFU‐GM osteoclast precursors cultured for 14 days on dentine with RANKL, with varying exposure to exogenous human M‐CSF. Short‐term treatment of precursors with M‐CSF (10–100 ng/mL) resulted in increased proliferation with or without RANKL. Treatment with M‐CSF (1–100 ng/mL) for 14 days caused a biphasic concentration‐dependent stimulation of formation, fusion, and resorption peaking at 10–50 ng/mL and almost complete abolition of resorption at 100 ng/mL. Time‐course studies using M‐CSF (25 ng/mL) showed that osteoclast size, nuclei/cell, and resorption increased with longer duration of M‐CSF treatment. When treatment was restricted to the first 4 days, M‐CSF (25–100 ng/mL) stimulated formation of normal numbers of osteoclasts that resorbed less. Blockade of endogenous M‐CSF signaling with neutralizing M‐CSF antibody during the first week of culture extensively inhibited osteoclastogenesis, whereas blockade during the second week produced only a small reduction in resorption. Treatment with M‐CSF during the second week of culture caused a small increase in osteoclast number and a concentration‐dependent increase in cytoplasmic spreading with inhibition of resorption. We have shown that M‐CSF modulates multiple steps of human osteoclastogenesis, including proliferation, differentiation and fusion of precursors. In the later stages of osteoclastogenesis, M‐CSF modulates osteoclast‐resorbing activity, but is not required for survival. Modulation of M‐CSF signaling is a potential therapeutic target for conditions associated with excess bone resorption. J. Cell. Biochem. 102: 759–768, 2007. © 2007 Wiley‐Liss, Inc.
Development and iron‐dependent expression of hephaestin in different brain regions of rats
Authors: Qian Zhong‐Ming , Chang Yan‐Zhong , Zhu Li , Yang Lei , Du Jun‐Rong , Ho Kwok‐Ping , Wang Qin , Li Lian‐Zhi , Wang Chen‐Yuen , Ge Xiaohu , Jing Niu Li , Li Lin , Ke Ya
Published: May 2007

It has been suggested that Hephaestin (Heph), a newly discovered ceruloplasmin homologue, is necessary for iron egress from the enterocytes into circulation via interacting with ferroportin1 (FP1). Based on the putative function of Heph, and the similarity between the process of iron transport in the enterocytes and that in the blood‐brain barrier (BBB) cells, it has also been proposed that Heph plays a similar role in exporting iron from the BBB cells and other brain cells as it works in the enterocytes via interacting with FP1. The existence of FP1 in the brain has been demonstrated. In this study, we investigated Heph expression and effects of development and iron in the cortex, hippocampus, striatum, and substantia nigra. The data demonstrated that all the four regions we examined have the ability to express Heph mRNA and protein. The findings also showed that both the development and iron status have a significant effect on Heph expression and the effects of iron status are regionally specific. It was also suggested that Heph expression is probably regulated at the transcriptional level by the development and iron in these brain regions. These findings, together with other published data, support a putative role of Heph in the iron metabolism in the brain. J. Cell. Biochem. 102: 1225–1233, 2007. © 2007 Wiley‐Liss, Inc.
Cilostazol attenuates MCP‐1 and MMP‐9 expression in vivo in LPS‐administrated balloon‐injured rabbit aorta and in vitro in LPS‐treated monocytic THP‐1 cells
Authors: Tsai Chien‐Sung , Lin Feng‐Yen , Chen Yung‐Hsiang , Yang Tung‐Lin , Wang Hsiao‐Jung , Huang Guo‐Shine , Lin Chih‐Yuan , Tsai Yi‐Tin , Lin Shing‐Jong , Li Chi‐Yuan
Published: May 2007

Monocyte chemoattractant protein‐1 (MCP‐1) and matrix metalloproteinase‐9 (MMP‐9) are involved in vascular inflammation. We tested the hypothesis, and explored the underlining mechanisms that cilostazol, a phosphodiesterase 3 inhibitor with antiplatelet and antithrombotic properties, inhibits lipopolysaccharide (LPS)‐induced MCP‐1 and MMP‐9 expression. In a rabbit aorta balloon‐injury model, administration of LPS increased macrophage infiltration and MCP‐1 and MMP‐9 expression; cilostazol supplementation prevented this phenomenon and reduced intimal hyperplasia. In contrast, the reverse zymography showed that cilostazol did not affect TIMP‐1 expression in serum. In monocytic THP‐1 cells, cilostazol and N6,O2′‐dibutyryl‐cAMP (dioctanoyl‐cAMP, a cAMP analog) dose‐dependently inhibited LPS‐induced MCP‐1 protein expression and MMP‐9 activation, but did not affect the tissue inhibitor of metalloproteinase‐1. Quantitative real‐time polymerase chain reaction (PCR) showed that cilostazol inhibited MCP‐1 and MMP‐9 mRNA expression. Cilostazol significantly inhibited LPS‐induced activation of p38, JNK, and nuclear factor‐κB, and the respective inhibitors of p38 and JNK greatly reduced the level of LPS‐induced MCP‐1 and MMP‐9, suggesting the involvement of the p38 and JNK pathways. In conclusion, cilostazol administered with LPS in vivo reduced neointimal hyperplasia and macrophage infiltration in the balloon‐injured rabbit aorta; in vitro, cilostazol inhibits LPS‐induced MCP‐1 and MMP‐9 expression. These data suggest that cilostazol may play an important role in preventing endotoxin‐ and injured‐mediated vascular inflammation. J. Cell. Biochem. 103: 54–66, 2008. © 2007 Wiley‐Liss, Inc.
Dexamethasone promotes osteoclastogenesis by inhibiting osteoprotegerin through multiple levels
Authors: Kondo Takeshi , Kitazawa Riko , Yamaguchi Akira , Kitazawa Sohei
Published: May 2007

Increased bone fragility attributed to osteopenia is a serious side effect of glucocorticoid treatment. Glucocorticoid‐induced bone loss is caused primarily by hypofunction and apoptosis of osteoblasts, and secondarily by accelerated bone resorption. To explore the mechanism whereby dexamethasone (Dex) stimulates osteoclastogenesis in the coculture system, we analyzed the effect of Dex on the expression of both mouse osteoprotegerin (OPG) and receptor activator of NF‐κB ligand (RANKL). Dex reduced OPG transcripts and OPG protein secretion by the ST2 osteoblastic cells. Since mainly the c‐Jun homodimer maintains the steady‐state transcription of the OPG gene, we examined the effect of Dex on c‐Jun signaling in ST2 cells. Western blotting disclosed that Dex decreased the amount of phospho‐c‐Jun protein (p‐c‐Jun) and, correspondingly, the amount of the phosphorylated p46 isoform of Jun N‐terminal kinase (JNK). The amount of phospho‐SEK1 also decreased after Dex treatment, while the amounts of phospho‐ERK and p38 remained constant. Among mitogen‐activated protein (MAP) kinase inhibitors, the JNK inhibitor mimicked the inhibitory effect of Dex on OPG promoter activity. On the other hand, Dex treatment per se showed a nominal increase of RANKL gene expression. A part of Dex‐mediated OPG gene suppression was achieved by the suppression of β‐catenin signaling. We speculate therefore that the bone resorptive action of Dex is mediated mainly by the inhibition of OPG by transrepressing the OPG gene through the AP‐1 site, with a reduction (mediated mainly by the decrease in the p46 isoform of JNK) in the proportion of p‐c‐Jun in a JNK‐dependent manner. J. Cell. Biochem. 103: 335–345, 2008. © 2007 Wiley‐Liss, Inc.
On the extendability of steiner t‐designs
Authors: Baartmans Alphonse H. , Blake Ian F. , Tonchev Vladimir D.
Published: May 2007

Necessary and sufficient conditions for the extendability of residual designs of Steiner systems S(t,t + 1,v) are studied. In particular, it is shown that a residual design with respect to a single point is uniquely extendable, and the extendability of a residual design with respect to a pair of points is equivalent to a bipartition of the block graph of a related design. © 1993 John Wiley & Sons, Inc.
Incomplete perfect mendelsohn designs with block size 4 and one hole of size 7
Authors: Bennett F. E. , Shen H. , Yin J.
Published: May 2007

Let v,k, and n be positive integers. An incomplete perfect Mendelsohn design, denoted by k‐IPMD(v,n), is a triple (X, Y, 𝔹) where X is a v‐set (of points), Y is an n‐subset of X, and 𝔹 is a collection of cyclically ordered k‐subsets of X (called blocks) such that every ordered pair (a, b) ∈ (X × X)∖(Y × Y) appears t‐apart in exactly one block of 𝔹 and no ordered pair (a,b) ∈ Y × Y appears in any block of 𝔹 for any t, where 1 ≤ t ≤ k − 1. In this article, we obtain conclusive results regarding the existence of 4‐IPMD(v,7) where the necessary conditions are v = 2 or 3(mod 4) and v ≥ 22. We also provide an application to the problem relating to coverings of PMDs with block size 4. © 1993 John Wiley & Sons, Inc.
Sprouty2 downregulation plays a pivotal role in mediating crosstalk between TGF‐β1 signaling and EGF as well as FGF receptor tyrosine kinase‐ERK pathways in mesenchymal cells
Authors: Ding Wei , Shi Wei , Bellusci Saverio , Groffen John , Heisterkamp Nora , Minoo Parviz , Warburton David
Published: May 2007

Mammalian Sprouty2 (Spry2) is a key regulator of the receptor tyrosine kinase/ERK signaling pathway and is involved in many biological processes, including cell growth, differentiation, migration, and embryonic lung branching morphogenesis. Previous studies have shown that Spry2 expression is upregulated by many mitogens, particularly epidermal growth factor (EGF) and fibroblast growth factors (FGFs). In contrast, we report that transforming growth factor‐β1 (TGF‐β1), which stimulates the growth of quiescent Swiss 3T3 cells, induced a dose dependent decrease of mouse Spry2 protein level within 24‐h of treatment, and this effect was mediated by a MAP kinase‐independent pathway. A concomitant reduction of the level of Spry2 mRNA indicates the involvement of a transcriptional mechanism, which requires histone deacetylase (HDAC) activity and de novo protein synthesis. On the other hand, the turnover rate of Spry2 protein was increased by TGF‐β1 treatment, suggesting enhanced Spry2 degradation. Treatment with lysosomal inhibitors, but not proteasome inhibitors, prevented the degradation of Spry2, thus, indicating that the degradation of Spry2 is mediated through the lysosomal pathway in Swiss 3T3 cells. Furthermore, we demonstrate that TGF‐β1 signaling can modulate EGF and FGF‐induced ERK‐MAP kinase activation by controlling Spry2 expression and function. Moreover, rescue of the TGF‐β1‐induced downregulation of Spry2 by gene over‐expression led to inhibition of the mitogenic effect of TGF‐β1 in Swiss 3T3 cells. Together, the combined operation of transcriptional and post‐translational mechanisms suggests that regulation of Spry2 is a crucial event and emphasizes the important role that Spry2 plays in controlling cell behaviors. J. Cell. Physiol. 212:796–806, 2007. © 2007 Wiley‐Liss, Inc.
Mitochondrial association of myocilin, product of a glaucoma gene, in human trabecular meshwork cells
Authors: Sakai Hiroshi , Shen Xiang , Koga Takahisa , Park Bum‐Chan , Noskina Yelina , Tibudan Martin , Yue Beatrice Y.J.T.
Published: May 2007

The trabecular meshwork (TM), an ocular tissue next to the cornea, is a major site for regulation of the aqueous humor outflow. Malfunctioning of this tissue is believed to be responsible for development of glaucoma, a major blinding disease. Myocilin is a gene directly linked to the most common form of glaucoma. Its protein product has been localized to both intra‐ and extra‐cellular sites in TM cells. This study was to investigate the association of myocilin with mitochondria in TM cells. In vitro mitochondrial import assays showed that myocilin was imported to the TM mitochondria, targeting to mitochondrial membranes and/or the intermembrane space. The targeting was mediated mostly via the amino‐terminal region of myocilin. When myocilin expression was induced either by treatment with dexamethasone or transfection with a myocilin construct, the mitochondrial membrane potential in TM cells, as assessed by JC‐1 staining, was lowered. Subcellular fractionation and Western blot analyses confirmed that a portion of myocilin sedimented with the mitochondrial fractions. Upon anti‐Fas treatment to provoke apoptosis, an increase of myocilin distribution in cytosolic fraction was observed, suggesting that myocilin was partially released from mitochondrial compartments. These results confirmed the association of myocilin with TM cell mitochondria and indicated that myocilin may have a proapoptotic role in TM cells. J. Cell. Physiol. 213:775–784. © 2007 Wiley‐Liss, Inc.
Adenosine A1 and A2A receptor effects on G‐protein cycling in β‐adrenergic stimulated ventricular membranes
Authors: Fenton Richard A. , Dobson James G.
Published: May 2007

In the heart β1‐adrenergic (β1R) and adenosine A1 (A1R) and A2A (A2AR) receptors modulate contractile and metabolic function. The interaction between these receptors was investigated at the level of G‐protein cycling by determining the effect of receptor agonists on the binding of GTP to G‐proteins and displacement of Gα‐subunit‐bound GDP by GTP. Crude membranes from rat heart or brain were stimulated by agonists for β1R (isoproterenol; ISO), A1R (chlorocyclopentyladenosine, CCPA) and A2AR (CGS‐21680; CGS). GTP binding to membranes was increased by ISO (17%), CCPA (6%) and CGS (12%). Binding values observed with incubation using ISO and CCPA together were significantly less than values obtained by the incubation of individual agents alone. With ISO, GTP binding to Gαs subunits as determined by immunoprecipitation was increased 79% in heart and 87% in brain. These increases were attenuated by CCPA, an effect that was inhibited by CGS. GDP release by membranes was increased 6.9% and 4.6% by ISO and CCPA, respectively. After co‐incubation of these agonists, release was increased less than determined by the addition of the individual agent responses. CGS inhibited the reduced release caused by of CCPA. Adenylyl cyclase activity stimulated by ISO was attenuated 33% by CCPA, an effect inhibited by CGS. Together, these results indicate that A1R exert an antiadrenergic action at the level of β1R stimulated Gs‐protein cycling and that A2AR reduce this action. J. Cell. Physiol. 213:785–792. © 2007 Wiley‐Liss, Inc.
Patch‐clamp ‘mapping’ of ion channel activity in human sperm reveals regionalisation and co‐localisation into mixed clusters
Authors: Jiménez‐González M.C. , Gu Y. , Kirkman‐Brown J. , Barratt C.L.R. , Publicover S.
Published: May 2007

Ion channels are pivotal to many aspects of sperm physiology and function. We have used the patch clamp technique to investigate the distribution of ion channels in the plasma membrane of the head of human spermatozoa. We report that three types of activity are common in the equatorial and acrosomal regions of the sperm head. Two of these (a chloride‐permeable anion channel showing long stable openings and a second channel which flickered between open and closed states and was dependent upon cyoplasmic factors for activity) were localised primarily to the equatorial segment. A third type, closely resembling the flickering actvivity but with different voltage sensitivity of Popen, was more widely distributed but was not detectable over the anterior acrosome. In the anterior acrosomal area channels were present but showed very low levels of spontaneous activity. A unique feature of channel activity in the sperm equatorial region was co‐localisation into mixed clusters, most patches were devoid of activity but ‘active’ patches typically contained two or more types of activity (in a single 200–300 nM diameter patch). We conclude that ion channels in the sperm membrane show regionalisation of type and activity and that the channels are clustered into functional groups, possibly interacting through local effects on membrane potential. J. Cell. Physiol. 213:801–808. © 2007 Wiley‐Liss, Inc.