bluuebunny/crossref_metadata_2025 huggingface dataset:
Isocyanatoethyl Methacrylate Telomerization and Cotelomerization
Authors: Lam Ousmene A. , Hervaud Yves , Boutevin Bernard
Published: February 2007

This article describes the use of isocyanatoethyl methacrylate (IEM) as a monomer in telomerization and cotelomerization reactions. First, the selectivity of benzenethiol addition to the unsaturation of IEM is proven. Even with an equimolar amount of reactants, benzenethiol reacts almost selectively with the ethylenic double bonds. The radical telomerization of IEM and its cotelomerization with MMA, in the presence of benzenethiol, has been achieved and shows that control of molecular weight is possible. Finally, the addition of a phosphonated alcohol to these telomers, followed by ester cleavage reactions, leads selectively to families of mono or diphosphonate products. The study of the thermal properties of the cotelomers shows that the degradation starts at 180 °C on the isocyanate group of IEM, and then on the ester group of MMA, and the decomposition is complete at 450 °C. The introduction of the phosphonated ester group decreases the glass transition temperature of the cotelomers, but after hydrolysis these values increase.

magnified image
Micellization of PS‐PMMA Diblock Copolymers in an Ionic Liquid
Authors: Simone Peter M. , Lodge Timothy P.
Published: February 2007

Three polystyrene‐block‐poly(methyl methacrylate) (PS‐PMMA) block copolymers with varying molecular content have been shown to form micelles when dissolved in the ionic liquid 1‐butyl‐3‐methylimidazolium hexafluorophosphate (BMIM PF6). The micellar structure was studied via cryogenic transmission electron microscopy and dynamic light scattering, and a morphological transition from spherical to cylindrical micelles was observed upon reduction of the PMMA volume fraction. The possibility of frozen micellar morphology was considered, due to the solution preparation method and high glass transition temperature (Tg) of the PS blocks that form the micellar cores. By comparison of the behavior of a 100 kDa PMMA homopolymer dissolved in both BMIM PF6and a known good solvent, acetone, it was determined that BMIM PF6behaves as a good solvent for PMMA. It was also observed that extended exposure to the electron beam during cryogenic transmission electron microscopy could damage the copolymer micelles and result in a reversal of contrast.

magnified image
A Facile Method to Prepare Hydrophobic Nanoparticle Dispersions for Controlled Release
Authors: Liu Yu‐Yang , Su Xia , Tang Min‐Feng , Kong Jie
Published: February 2007

Using ethyl acrylate and methyl methacrylate as hydrophobic monomers, a series of hydrophobic nanoparticle dispersions were prepared by one‐step polymerization (i.e., soap‐free batch emulsion polymerization). To obtain stable aqueous nanoparticle dispersions, a small amount of ionic comonomer, sodium 4‐ω‐acryloyloxy‐β‐hydroalkyl sulfonate (Cops‐1) was used. The nanoparticles were characterized by TEM, Zetasizer and DSC. It was found that number average diameter ($\overline D _{\rm n}$) values range from 144 to 202 nm at 25 °C, and the diameter distribution ($\overline D _{\rm v} /\overline D _{\rm n}$) from 1.11 to 1.14. These results indicate that the nanoparticles show a narrow distribution of sizes. Zeta potentials of the obtained nanoparticles are in range of −38.8 to −29.7 mV at 25 °C. This suggests that they can be well dispersed in water. Using salicylic acid (SA) as model drug molecules, a novel swelling method was developed for loading SA into the nanoparticles in an aqueous dispersion state, and both related loading processes and controlled release behavior were investigated. It was found that the nanoparticles can sustain SA release, and compared to different types of nanoparticles, PMMA nanoparticles can retard SA release more effectively.

magnified image
The Orientation and Photophysical Properties of Conjugated Polymers in Oriented Films
Authors: He Benqiao , Wu Changcheng , Huang Yong
Published: February 2007

Highly oriented light‐emitting blend films containing poly(9,9‐dioctylfluorene) (PFO), PFO with one fluorenone unit (PFF), and ultrahigh‐molecular‐weight polyethylene (U‐PE) are prepared by using a tensile deformation technique. A high dichroic ratio of 36 in photoluminescence from the oriented film is obtained. The photophysical properties of the PFF/PFO blend are investigated in the blend films. In particular, the origin of the green band (‘g‐band’) that often undesirably appears from PFO used in air, is discussed in such a highly oriented circumstance. The experimental results powerfully demonstrate that the g‐band originates from the mono‐chain fluorenone moieties, rather than the fluorenone‐based excimer.

magnified image
Cover Picture: Macromol. Theory Simul. 2/2007
Authors: Zhong Chongli , Liu Dahuan
Published: February 2007

Cover: The picture on the cover shows the structures of copolymer chains and the morphologies of multicompartment micelles formed from them in a selective solvent, illustrating that various morphologies can be formed by changing chain architecture, composition, and/or solvent quality. Further details can be found in the article by C. Zhong* and D. Liu on page 141.
The paradox of inelastic sports pricing
Authors: Porter Philip K.
Published: February 2007

Rodney Fort's (2004) article in Managerial and Decision Economics attempts to explain the recurrent phenomenon of inelastic ticket pricing in professional sports. In his explanation, Fort mistakenly substitutes the marginal revenue generated by the acquisition of talent for the marginal revenue generated by lowering the gate ticket price. This article corrects the mistake, pointing out that inelastic ticket pricing is still inconsistent with profit maximization. In addition, it is demonstrated that the marginal revenue generated by additional talent cannot be negative. Copyright © 2007 John Wiley & Sons, Ltd.
Investment in organizational capital
Authors: Gomes Orlando
Published: February 2007

Organizational capital is a specific form of capital that firms accumulate. It relates to the development of codes, technical languages, practical arrangements about how the work is done and to the creation of an organizational culture. The distinctive feature of this form of capital is the fact that it does not contribute directly to an output result. Instead, it can be thought as creating the correct environment for the human factor to maximize its capability of generating value, that is, organizational capital works as an external effect on the accumulation of the human capital input. Nevertheless, organizational capital is a form of capital and therefore it has an investment process associated with it. The paper considers the process of investment in this form of capital and recognizes that it introduces important changes over the firm's profit maximization problem. The problem gains new features relating to its dynamic nature and a condition that guarantees saddle‐path stability can be derived. Copyright © 2007 John Wiley & Sons, Ltd.
Credible collusion in multimarket oligopoly
Authors: Sorenson Timothy L.
Published: February 2007

This article refines an established explanation of how multimarket contact facilitates collusion when firms enjoy reciprocal advantages across markets: When there are reciprocal asymmetries between firms, multimarket contact allows them not only to develop spheres of influence, but also to implement attractively simple strategies that are subgame perfect and weakly renegotiation proof. Hence, collusive equilibria are supported by fully credible punishments. A significant implication is, multimarket contact involving reciprocal differences between firms may be more facilitating to their cooperative efforts than multimarket contact based on other factors. The article discusses existing empirical work as it relates to this implication. Copyright © 2007 John Wiley & Sons, Ltd.
Firm governance and duopoly: in weakness may lie strength
Authors: Brady Malcolm P.
Published: February 2007

The paper proposes a model of firm governance when two firms compete in a duopoly. The paper assumes that a motivational asymmetry exists between owners and managers: owners wish to obtain maximum profits, managers wish to maximize sales. Managers perceive that salary, social status or future job prospects are more closely associated with firm size (i.e. sales) than with firm profits. The paper takes an agency view of the firm where owners only indirectly influence the behaviour of firms through the level of control they exert over managers. The paper demonstrates that a weakly governed firm, acting as a sales maximizer, can gain a competitive advantage over a strongly governed firm, acting as a profit maximizer. The paper examines the extent of this advantage under cost leadership and differentiation strategies. The paper also demonstrates that the objectives of profit maximization and maximization of competitive advantage are not necessarily congruent. The paper graphically represents the profit functions of the two firms illustrating the Nash equilibrium under Cournot and Stackelberg conditions. Copyright © 2007 John Wiley & Sons, Ltd.
Microsurgery and music: Parallel ideas and philosophy?
Authors: Nemeth Norbert
Published: February 2007

Can a philosophic analogy be drawn between music, a major formal area and discipline of the fine arts, and microsurgery, a branch of applied medical science and research? Is an interdisciplinary view of value? Should we look for links beyond the stated boundaries of each of these areas? These are questions that fascinate physicians who, apart from their professional scientific activity, are also involved in making music a way to enrich their lives. In this paper a medical researcher, physician, and composer gives words to his thoughts about the parallel ideas and philosophies of these two disciplines. © 2007 Wiley‐Liss, Inc. Microsurgery, 2007.
Experimental orthotopic tracheal transplantation: The stanford technique
Authors: Schrepfer Sonja , Deuse Tobias , Hoyt Grant , Sheikh Ahmad Y. , Hoffmann Joerg , Reichenspurner Hermann , Robbins Robert C. , Pelletier Marc P.
Published: February 2007

The rat heterotopic tracheal transplantation model is widely used as an experimental model to study the development of obliterative airway disease (OAD) and to assess immunosuppressive strategies for chronic rejection. Despite its widespread application, the heterotopic transplantation model does have a number of limitations like the lack of air flow and mucociliary clearance. The present article provides a detailed description of the surgical technique for orthotopic tracheal transplantations, which may share more similarities with lung transplants in humans. The technique is easy to learn, the procedure is well tolerated by the animals, and the grafts develop OAD lesions similar to those of human obliterative bronchiolitis. © 2007 Wiley‐Liss, Inc. Microsurgery, 2007.
Counterposition and negative refraction due to uniform motion
Authors: Mackay Tom G. , Lakhtakia Akhlesh
Published: February 2007

Refraction of obliquely incident plane waves due to the interface of a vacuous half‐space and a half‐space occupied by a simply moving, nondissipative, isotropic dielectric‐magnetic medium is considered, when the medium's velocity lies parallel to the interface and in the plane of incidence. Counterposition of the refracted wave vector and time‐averaged Poynting vector occurs when the medium's velocity is sufficiently large in magnitude and makes an obtuse angle with the incident wave vector. The counterposition induced by relative motion occurs whether the refraction is negative or positive when the medium is at rest. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 874–876, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI.10.1002/mop.22250
A compact dual‐band chip antenna using a nonuniform meander‐line to suppress spurious emissions
Authors: Lee Cheng‐Ta , Lin Ming‐Shing , Chiu Cheng‐Nan
Published: February 2007

A compact chip antenna specified for use in IEEE 802.11b/g/a wireless local‐area network applications is proposed. This antenna uses a nonuniform meander‐line to generate the desired radiation bands and suppress spurious emissions outside these bands. A prototype of this compact antenna with dimensions, 9.4 × 4 × 1.7 mm3, has been constructed and demonstrates satisfactory performance. Measured and simulated results, including return loss and radiation patterns of the antenna, have been obtained. These results show that the impedance bandwidth is sufficient and that the radiation is omnidirectional in the specified bands. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 773–776, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22251
Electromagnetic analysis of large structures by using a hybrid early‐time and low‐frequency methodology
Authors: Lee Wonwoo , Yuan Mengtao , Sarkar Tapan K.
Published: February 2007

In this paper, we present an electromagnetic analysis for three‐dimensional arbitrarily shaped large structures illuminated by a short pulse. The time domain electric field integral equation (EFIE) formulation is used to obtain the early time data with a central differencing scheme to evaluate the time derivatives of the potential functions. The solution method is based on the method of moments (MoM) and marching‐on‐in‐time (MOT) technique. Low frequency data is generated using a frequency domain integral equation method. The hybrid method is based on the singular value decomposition (SVD) of the frequency and the time domain data for a direct extrapolation of a causal signal. The detailed mathematical procedures are included along with representative numerical results from an aircraft model. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 898–904, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22253
Tunable and injection‐switchable erbium‐doped fiber laser of line structure
Authors: Chen Daru , Qin Shan , Yu Zhangwei , He Sailing
Published: February 2007

A tunable and injection‐switchable erbium‐doped fiber (EDF) laser is proposed based on a line structure formed by a fiber Sagnac loop reflector and an fiber Bragg grating (FBG). Wavelength switching is achieved by controlling the power of the tunable injection laser. The self‐seeded wavelength corresponding to the Bragg wavelength of the FBG can be tuned by, for example, heating the FBG, and the injection wavelength can be tuned over a wide range of about 50 nm. The characteristics of the wavelength switching for different levels of the EDF pump power and different wavelengths of the injection laser are studied experimentally. The present fiber laser has the advantages of tunability, stability, low amplified spontaneous emission noise, and high injection efficiency when compared with a fiber ring laser. Rapid wavelength switching is expected and the transient switching response of the laser is also studied. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 765–768, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22262
Receiving mutual impedance between two printed dipole antennas
Authors: Lee W. M. , Yap Y. , Hui H. T.
Published: February 2007

A new mutual impedance, the receiving mutual impedance, between two printed dipole antennas was rigorously determined by experimental measurements. The variations of the receiving mutual impedance with antenna separation and with frequency were obtained. The receiving mutual impedance obtained differs significantly from the conventional mutual impedance, which was shown to be not suitable to indicate the mutual coupling effect in receiving arrays. Results are useful for printed dipole array design. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 892–896, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22263
Some novel design for RFID antennas and their performance enhancement with metamaterials
Authors: Stupf M. , Mittra R. , Yeo J. , Mosig J. R.
Published: February 2007

In this paper we discuss a number of UHF/RFID tag designs including the hybrid loop (Chen and Hsu, International Symposium on Antennas and Propagation, Korea, Vol. 3, 2005, 1045–1048), dual crossed‐dipoles, the dual crossed‐dipoles utilizing an inductively coupled feed (Choo and Ling, Electron Lett 39 (2003) 3080–3081). We have carried out extensive parametric studies in the process of analyzing the characteristics of the earlier‐mentioned antennas, and have investigated several techniques (Choo and Ling, Electron Lett 39 (2003) 3080–3081), including meandering, for size‐reduction of these antennas. A design methodology based on the Genetic Algorithm (GA) is presented for the optimization of conformal antennas with Electromagnetic Bandgap (EBG) surfaces (Mittra, Proceedings of International Symposium on Antennas and Propagation 2005 (ISAP2005) Seoul, Korea, 2005, 325–328; Sievenpiper et al., IEEE Trans Microwave Theory Tech 47 (1999), 2059–2074) to improve the antenna performance. The EBG characteristic is realized by utilizing a Frequency Selective Surface (FSS) placed above a thin dielectric substrate backed by a metallic ground plane to act as an Artificial Magnetic Conductor (AMC). The antenna is then placed above the EBG surface to create a conformal integrated EBG ‐ antenna. The initial design of the AMC is carried out by synthesizing a surface whose reflectivity is “+1”, for a normally incident plane wave. However, since the antenna situated above it produces not just a single plane wave but a spectrum of these waves, it becomes necessary to refine the initial design to optimize the performance of the antenna/AMC composite, and techniques for doing this are discussed in the paper. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 858–867, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI.10.1002/mop.22265
Design of H‐shaped microstrip patch antennas
Authors: Ooi S. F. , Lee S. K. , Sambell A. , Korolkiewicz E. , Scott S.
Published: February 2007

Based on the symmetric properties of the antenna, the design equations for the first four mode frequencies are derived. A design methodology for an antenna operating at 2.45 GHz is presented. Two antennas have been designed and tested, and good agreement among the predicted, simulated, and measured results is obtained. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 791–795, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22269
Useful integration quadrature for electromagnetics the Erf transform
Authors: Ooi B. L.
Published: February 2007

The application of the Erf transformation in the efficient and accurate evaluation of singular integrals is considered. It is shown that the transform can also be utilized in the efficient extrapolation computation of infinite integrals. An optimal grid spacing for the Erf transformation is proposed. Several numerical illustrations are given to show the usefulness of the proposed method in computational electromagnetics. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 789–791, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22270
Determination of pregnancy using microwaves
Authors: Lonappan Anil , Rajasekaran C. , Thomas Vinu , Bindu G. , Mathew K. T.
Published: February 2007

In today's life, microwave technology is used in both diagnostic and therapeutic procedure. This letter presents the study of dielectric properties of pregnant women urine as well normal women urine at microwave frequencies. In vitro measurements using cavity perturbation technique is employed in the frequency range between 2 and 3 GHz. It is observed that dielectric constant of pregnant women urine samples is smaller than the normal women urine samples and the conductivity of pregnant women urine samples is higher than that of normal women urine samples, which is a novel alternative in vitro method of determining pregnancy, and is required for a woman to make preparations for proper prenatal care and family planning. The same samples are subjected to investigations in the clinical laboratory for quantitative analysis, which holds good for our microwave study. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 786–788, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22279
Analyses and wideband modeling (DC‐to‐50 GHz) of dummy open devices on silicon for accurate RF devices and ICS de‐embedding applications
Authors: Lin Yo‐Sheng , Chen Chi‐Chen , Liang Hsiao‐Bin , Huang Meng‐Shiung
Published: February 2007

In this work, a dummy open device with ground guard‐ring and another dummy open device without ground guard‐ring were measured and modeled from DC‐to‐50 GHz for precise de‐embedding of the parasitic part which surrounds the intrinsic part of the RF devices (i.e. MOSFET, SiGe HBT, etc.) and the RF‐ICs on silicon. The results show that both the input impedance and the output impedance of the dummy open device with ground guard ring can be simplified to a simple series RC circuit at low frequencies, and then a “shifted” parallel RC circuit at high frequencies. It is this intrinsic ambivalent characteristic of the input and the output impedance that causes the appearance of the kink phenomena of S11 and S22 in the Smith chart. Moreover, the reason why adding a ground guard‐ring underneath the signal pad makes the kink phenomena of S11 and S22 less prominent (or disappeared) can also be explained by our theory. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 879–882, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22283
Digitally defined wireless transmitter based on Class E amplifier
Authors: Brabetz Thorsten , Fusco Vincent F.
Published: February 2007

This novel digitally defined transmitter without digital‐to‐analog converters is based on Class E amplifiers' ability to transform a digital input signal into an analog RF output signal. The validity of the system is proven by successful demodulation of a QPSK signal generated by the transmitter from a pulse‐position‐modulation input signal. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 843–846, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22285
Internal broadband diversity dipole antenna
Authors: Su Saou‐Wen , Chou Jui‐Hung , Wu Tzuenn‐Yih
Published: February 2007

An internal printed diversity antenna mounted on a PCMCIA network card for broadband operation is presented. The antenna has a low profile of 6 mm to the network card and a small protruded length of 3 mm. The diversity antenna comprises two back‐to‐back dipoles, and each dipole is further comprised of a longer and a shorter radiating arms. The two radiating arms have complementary shape such as to make the antenna tend to be a self‐complementary structure, thus leading to a wide operating bandwidth of ∼4.6 GHz (approximately 2.9 ∼ 7.5 GHz). © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 810–812, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22287
Swamping of circular Bragg phenomenon and shaping of videopulses
Authors: Geddes Joseph B. , Lakhtakia Akhlesh
Published: February 2007

We studied the durations and average speeds of videopulses transmitted through chiral sculptured thin films using a finite‐difference algorithm. The chiral STF was either linear or possessed an intensity‐dependent permittivity. Videopulse durations tended to decrease with increasing carrier wavelength and to increase, for given carrier wavelength and polarization state, when the chiral STF was nonlinear with intensity‐dependent permittivity. The rate of decrease in durations with wavelength was less than that for longer‐duration pulses. The effect of the circular Bragg phenomenon was swamped by the wide bandwidth possessed by videopulses. Two measures of videopulse average speed did not change much with carrier wavelength, and decreased slightly for a given carrier wavelength and polarization state in the nonlinear case. The other measure of average speed tended to increase with increasing carrier wavelength, and decrease for a given carrier wavelength and polarization state in the nonlinear case. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 776–779, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22290
Design of compact CPW bandpass filters with wide stopband
Authors: Lin Li‐Jing , Ho Min‐Hua , Xu Wei‐Qin
Published: February 2007

Two compact bandpass filters composed of the lumped elements in various coplanar waveguide (CPW) forms have been presented in this study. The filters were designed to operate at the frequency of 2.45 GHz. The behaviors of these filters can be simulated by the equivalent lumped‐element circuit models with each element realized by the corresponding CPW discontinuity. Simulation and measurements were found to be in good agreement. Most attractive of all, the improved‐design filter has achieved about a 363% (9.04 GHz) stopband bandwidth under a 20 dB out‐of‐band rejection, and the measured passband's minimum insertion loss is around −1.24 dB with 10.84% 3‐dB bandwidth. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 973–976, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22299
High‐performance single‐turn interlaced‐stacked transformers for Ka‐band CMOS RFIC applications
Authors: Lin Yo‐Sheng , Chen Chi‐Chen , Liang Hsiao‐Bin , Yeh Po‐Feng , Wang Tao , Lu Shey‐Shi
Published: February 2007

In this article, we demonstrate that high‐coupling and ultra‐low‐loss transformers for Ka‐Band (26–40 GHz) CMOS RFIC applications can be achieved by using single‐turn interlaced‐stacked (STIS) structure implemented in a standard 0.18‐μm CMOS technology. State‐of‐the‐art GAmax of 0.777, 0.852, and 0.799 (i.e., NFmin of 1.097, 0.695, and 0.977 dB) were achieved at 30, 36, and 40 GHz, respectively, for a 2‐layer STIS transformer with an inner dimension of 100 × 100 μm2 and a metal width of 10 μm, mainly due to the high magnetic‐coupling factor and the high resistive‐coupling factor. Furthermore, the reasons why the STIS transformer exhibits better performances than the traditional bifilar and the traditional stacked transformer are explained. These results show that the STIS transformers are very promising for high‐performance Ka‐Band CMOS RFIC applications. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 936–942, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22301
A hairpin line wideband bandpass filter design with embedded open stubs
Authors: Hung Cheng‐Yuan , Weng Min‐Hang , Su Yan‐Kuin , Yang Ru‐Yuan
Published: February 2007

In this paper, a compact three‐poles hairpin line wideband bandpass filter with several embedded open stubs to improve the stopband is designed and implemented on print circuit board substrate. This filter at center frequency f0 of 4.25 GHz has presented almost very good measured characteristics, including the bandwidth of 3.1–5.4 GHz (3‐dB fractional bandwidth of 54%), low insertion loss of −0.7 ± 0.4 dB, sharp rejection due to two transmission zeros in the passband edge created by interstage coupling, and wide stopband rejection greater than 15 dB from 5.6 to 11 GHz. Experimental results of the fabricated filter show a good agreement with the predict results. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 934–936, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22302
Application of the high‐order symplectic FDTD scheme to the curved three‐dimensional perfectly conducting objects
Authors: Sha Wei , Wu Xianliang , Chen Mingsheng , Huang Zhixiang
Published: February 2007

A high‐order symplectic finite‐difference time‐domain (SFDTD) scheme using the diagonal split‐cell model is presented to analyze electromagnetic scattering of the curved three‐dimensional perfectly conducting objects. On the one hand, for the undistorted cells, the fourth‐order accurate spatial difference is employed. On the other hand, for the completely distorted cells, the treatment of the curved surfaces is based on the diagonal split‐cell model. Finally, for the partially distorted cells, the interpolation strategy is proposed to keep the field components continuous. The numerical experiments suggest that the diagonal SFDTD scheme can obtain more accurate results than both the staircased SFDTD scheme and the traditional diagonal FDTD method. Furthermore, in view of the high numerical stability, the improved symplectic scheme does not need to decrease time increment to comply with the stability criterion. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 931–934, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22306
Wavelet‐Galerkin of time domain method to analyze the scattering problems of randomly rough surface
Authors: Dai Shao‐yu , Wu Zhen‐sen
Published: February 2007

A Monte‐Carlo Wavelet‐Galerkin of Time Domain technique is presented for wave scattering from randomly rough, one‐dimensional PEC surface, and a numerical interface is applied to overcome the complexity of connection and absorption boundaries. The bistatic RCS for the surface with Gaussian surface roughness spectra are obtained using this technique. Results are in good agreement with MoM. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 928–931, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22307
Single‐feed square‐ring patch antenna with dual‐frequency operation
Authors: Chen Shing‐Hau , Row Jeen‐Sheen , Sim Chow‐Yen‐Desmond
Published: February 2007

The paper presents the design of a dual‐frequency patch antenna with different radiation patterns. The antenna structure is composed of a square‐ring patch and two shorting walls. Two resonant modes, patch‐loaded monopole mode and normal patch mode, can be simultaneously excited in the antenna structure by a coupling strip inide the square‐ring patch. Therefore, the antenna can radiate monopole‐like and broadside patterns at two operating frequencies, respectively. Several prototypes of the proposed dual‐frequency patch antenna with the frequency ratios ranging from 1.18 to 1.73 are constructed, and the obtained experimental results are also shown. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 991–994, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22308
TM and TE frequencies of the lens waveguide
Authors: Wang C. Y.
Published: February 2007

The electromagnetic frequencies (both TM and TE) are determined for the simple lens waveguide, which is bounded by two symmetric circular arcs. The Ritz method is shown to be efficient and accurate. It is found that the 5:1 aspect ratio separates the modes better than the 2:1 aspect ratio. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 918–920, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22317
An UWB planar out‐of‐phase power divider employing parallel stripline‐microstrip transitions
Authors: Abbosh A. M. , Bialkowski M. E.
Published: February 2007

The design of a planar out‐of‐phase (180°) power divider with an ultra wideband performance is presented. The device employs two dielectric substrates with a common ground plane. A transition from a parallel stripline to two microstrip lines is formed to divide power equally and with 180° phase difference from a stripline input port to two microstrip line output ports. The simulated and measured results of the proposed divider show equal power division with high stability of phase, good return loss at the three ports, low insertion losses, and fine isolation between the two output ports across the band from 3 to more than 11 GHz. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 912–914, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22324
Simple design for cost‐effective diversity antennas
Authors: Belmar‐Moliner N. , Valero‐Nogueira A. , Cabedo‐Fabrés M. , Antonino‐Daviu E.
Published: February 2007

This letter shows a simple design for a diversity planar monopole antenna with two feed points that can be used in multiple input multiple output (MIMO) systems. The design is based on the theory of characteristic modes. The final antenna has two highly isolated ports with an envelope correlation of less than 0.02 at the central frequency. This fact shows that the antenna meets the requirement for achieving diversity, and therefore, capacity. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 994–996, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22325
Spectroscopic characterization of 6‐hydroxy and 1‐methyl‐6‐hydroxybicyclo[2.2.2]octan‐2‐one ethylene acetals and ethylene dithioacetals
Authors: Leonelli Francesca , Garofalo Barbara , La Bella Angela , Lasta Ermanno , Ceccacci Francesca , Migneco Luisa M. , Marini Bettolo Rinaldo
Published: February 2007

6‐endo‐ and 6‐exo‐Hydroxybicyclo[2.2.2]octan‐2‐one and 1‐methyl‐6‐endo‐ and 6‐exo‐hydroxybicyclo[2.2.2]octan‐2‐one ethylene acetals and ethylene dithioacetals 1–4 have been characterized by 1D and 2D NMR methods. Copyright © 2007 John Wiley & Sons, Ltd.
Language phenotypes and intervention planning: Bridging research and practice
Authors: Fidler Deborah J. , Philofsky Amy , Hepburn Susan L.
Published: February 2007

This paper focuses on the communication and language phenotypes associated with three genetic disorders: Down syndrome, Williams syndrome, and fragile X syndrome. It is argued that there is empirical evidence that these disorders predispose children to specific profiles of strength and weakness in some areas of speech, language, and communication, and that intervention planning for children with each syndrome may take an approach informed by these profiles. Issues related to within‐group variability, shared outcomes among syndromes, and the need for empirical validation for syndrome‐specific recommendations are discussed. © 2007 Wiley‐Liss, Inc. MRDD Research Reviews 2007; 13:47–57.
The state of research and practice in augmentative and alternative communication for children with developmental/intellectual disabilities
Authors: Wilkinson Krista M. , Hennig Shannon
Published: February 2007

Augmentative and alternative communication is a compilation of methods and technology designed to supplement spoken communication for people with limited speech or language skills, including children with developmental and intellectual disabilities. The field of AAC has evolved rapidly within the last 10 years, due to a combination of empirical advances from research as well as rapid changes in technology. This article reviews some of the most significant aspects of this growth as it relates to children with developmental disabilities. Major issues within the field, the evidence base available to practitioners and researchers, and promising areas of future growth are identified. © 2007 Wiley‐Liss, Inc. MRDD Research Reviews 2007;13:58–69.
Early communication development and intervention for children with autism
Authors: Landa Rebecca
Published: February 2007

Autism is a neurodevelopmental disorder defined by impairments in social and communication development, accompanied by stereotyped patterns of behavior and interest. The focus of this paper is on the early development of communication in autism, and early intervention for impairments in communication associated with this disorder. An overview of components of communication is provided. Communication characteristics that are diagnostic of autism are summarized, with consideration of the overlap between social and communication impairment, particularly for children with autism functioning at the prelinguistic level. Early communication development and predictors of communication functioning in autism are examined, based on a review of prospective and retrospective studies. The focus of the discussion then turns to intervention. Consideration is given to the rationale for beginning intervention as early in life as possible for children with autism. Implications of motor, imitation, and play deficits for communication‐based intervention are examined. Finally, issues related to the design and delivery of intervention for young children with autism are presented, along with a review of the major early intervention approaches for autism. © 2007 Wiley‐Liss, Inc. MRDD Research Reviews 2007;13:16–25.
Dynamically shimmed multivoxel 1H magnetic resonance spectroscopy and multislice magnetic resonance spectroscopic imaging of the human brain
Authors: Koch Kevin M. , Sacolick Laura I. , Nixon Terence W. , McIntyre Scott , Rothman Douglas L. , de Graaf Robin A.
Published: February 2007

In vivo multivoxel Magnetic Resonance Spectroscopy (MRS) and multislice Magnetic Resonance Spectroscopic Imaging (MRSI) are extremely susceptible to poor homogeneity of the static magnetic field. Existing room‐temperature (RT) shim technology can adequately optimize the B0 homogeneity of local volumes, such as single voxels. However, the widespread global homogeneity required for in vivo spectral acquisitions from multiple volumes in the human brain cannot be attained with a single RT shim setting. Dynamic shim updating (DSU) allows for use of local RT shim B0 homogeneity compensation capabilities in a global fashion. Here, by updating first‐ and second‐order shims on a voxel‐ and slice‐specific basis using a pre‐emphasized DSU system, we present multivoxel MRS and multislice MRSI of the human brain. These results demonstrate that DSU can increase multivoxel MRS acquisition capabilities and significantly improve the quality of multislice MRSI data. Magn Reson Med 57:587–591, 2007. © 2007 Wiley‐Liss, Inc.
Sources of phase changes in BOLD and CBV‐weighted fMRI
Authors: Zhao Fuqiang , Jin Tao , Wang Ping , Hu Xiaoping , Kim Seong‐Gi
Published: February 2007

Phase changes in blood oxygenation‐level dependent (BOLD) fMRI have been observed in humans; however, their exact origin has not yet been fully elucidated. To investigate this issue, we acquired gradient‐echo (GE) BOLD and cerebral blood volume (CBV)‐weighted fMRI data in anesthetized cats during visual stimulation at 4.7T and 9.4T, before and after injection of a superparamagnetic contrast agent (monocrystalline iron oxide nanoparticles, MION), respectively. In BOLD fMRI, large positive changes in both magnitude and phase were observed predominantly in the cortical surface area, where the large draining veins reside. In CBV‐weighted fMRI, large negative changes in both magnitude and phase were detected mainly in the middle cortical area, where the greatest CBV change takes place. Additionally, the phase change was temporally correlated with the magnitude response and was linearly dependent on the echo time (TE), which cannot be explained by the intravascular (IV) contribution and functional temperature change. Phase changes with the opposite polarity were also observed in the regions around the dominant phase changes. These phase changes can be explained by the application of the “Lorentz sphere” theory in the presence of relevant activation‐induced changes in vessels. The volume‐averaged magnetization and its demagnetization are the main sources of fMRI signal phase change. Magn Reson Med 57:520–527, 2007. © 2007 Wiley‐Liss, Inc.
Serial MRI of carotid plaque burden: Influence of subject repositioning on measurement precision
Authors: Balu Niranjan , Kerwin William S. , Chu Baocheng , Liu Fei , Yuan Chun
Published: February 2007

MRI has the potential to track changes in the size of carotid atherosclerotic plaques for patient monitoring or in clinical trials. For either application, highly reproducible serial measurements are critical for drawing accurate conclusions. This study investigates the role of inconsistent repositioning of the artery from scan to scan in overall measurement variability. The total variability of cross‐sectional area measurements is modeled as a combination of variability due to segmentation differences, changes in orientation of the artery, and longitudinal offsets of the image location. Model parameters were generated using measurements from carotid arteries imaged in vivo. Comparison with actual reproducibility measurements for the lumen and outer wall boundaries showed that the errors were accurately predicted by the model, including a strong correlation between lumen and wall measurement differences. Orientation variability was the single most important factor that affected reproducibility, which suggests that methods are needed to obtain consistent orientation of the artery relative to the image plane. Magn Reson Med 57:592–599, 2007. © 2007 Wiley‐Liss, Inc.
Hyperpolarized 13C MRI of the pulmonary vasculature and parenchyma
Authors: Ishii Masaru , Emami Kiarash , Kadlecek Stephen , Petersson J. Stefan , Golman Klaes , Vahdat Vahid , Yu Jiangsheng , Cadman Robert V. , MacDuffie‐Woodburn John , Stephen Michael , Lipson David A. , Rizi Rahim R.
Published: February 2007

The study of lung perfusion in normal and diseased subjects is of great interest to physiologists and physicians. In this work we demonstrate the application of a liquid‐phase hyperpolarized (HP) carbon‐13 (13C) tracer to magnetic resonance imaging (MRI) of the pulmonary vasculature and pulmonary perfusion in a porcine model. Our results show that high spatial and temporal resolution images of pulmonary perfusion can be obtained with this contrast technique. Traditionally, pulmonary perfusion measurement techniques have been challenging because of insufficient signal for quantitative functional assessments. The use of polarized 13C in MRI overcomes this limitation and may lead to a viable clinical method for studying the pulmonary vasculature and perfusion. Magn Reson Med 57:459–463, 2007. © 2007 Wiley‐Liss, Inc.
Multispectral tissue characterization in a RIF‐1 tumor model: Monitoring the ADC and T2 responses to single‐dose radiotherapy. Part II
Authors: Henning Erica C. , Azuma Chieko , Sotak Christopher H. , Helmer Karl G.
Published: February 2007

A multispectral (MS) approach that combines apparent diffusion coefficient (ADC) and T2 parameter maps with k‐means (KM) clustering was employed to distinguish multiple compartments within viable tumor tissue (V1 and V2) and necrosis (N1 and N2) following single‐dose (1000 cGy) radiotherapy in a radiation‐induced fibrosarcoma (RIF‐1) tumor model. The contributions of cell kill and tumor growth kinetics to the radiotherapy‐induced response were investigated. A larger pretreatment V1 volume was correlated with decreased tumor growth delay (TGD) (r = 0.68) and cell kill (r = 0.71). There was no correlation for the pretreatment V2 volume. These results suggest that V1 tissue is well oxygenated and radiosensitive, whereas V2 tissue is hypoxic and therefore radioresistant. The relationship between an early ADC response and vasogenic edema and formation of necrosis was investigated. A trend for increased ADC was observed prior to an increase in the necrotic fraction (NF). Because there were no changes in T2, these observations suggest that the early increase in ADC is more likely based on a slight reduction in cell density, rather than radiation‐induced vasogenic edema. Quantitative assessments of individual tissue regions, tumor growth kinetics, and cell kill should provide a more accurate means of monitoring therapy in preclinical animal models because such assessments can minimize the issue of intertumor variability. Magn Reson Med 57:513–519, 2007. © 2007 Wiley‐Liss, Inc.
Aromatic poly(sulfone sulfide amide imide)s as new types of soluble thermally stable polymers
Authors: Mehdipour‐Ataei Shahram , Hatami Mehdi
Published: February 2007

A new diamine monomer containing flexible sulfone, sulfide, and amide units was prepared via three steps. Nucleophilic chloro displacement reaction of 4‐aminothiophenol with 4‐nitrobenzoyl chloride in the presence of propylene oxide afforded N‐(4‐mercapto‐phenyl)‐4‐nitrobenzamide and subsequent reduction of the nitro intermediate led to 4‐amino‐N‐(4‐mercapto‐phenyl)benzamide. Two moles of this amino thiophenol compound was reacted with bis‐(4‐chloro phenyl)sulfone to provide a novel diamine monomer. The diamine was reacted with aromatic dianhydrides to form polyimides via a two‐step polycondensation method, formation of poly(amic acid)s, followed by chemical imidization. The resulting polymers were characterized and their physical properties including thermal behavior, thermal stability, solubility and inherent viscosity were studied. Copyright © 2007 John Wiley & Sons, Ltd.
Thermochromic cellulose fibers
Authors: Rubacha Marcin
Published: February 2007

A method of obtaining thermochrome cellulose fibers has been developed. The basis technology used to form fibers was the Lyocell process. This method is based on spinning fibers from concentrated solvents of cellulose, using dry‐wet method in aqueous solidification bath. The cellulose solvent used in this process was N‐oxide‐N‐methylomorpholine (NMMO). The studies were to check on the features of the fibers obtained from solvents with thermochrome pigmentation, in order to evaluate their practical use. Thermochrome modifier used in the experiment was Chromicolor®AQ‐INK, Magenta type#27 pigmentation. This modifier was introduced into the spinning solutions in such amounts that fibers obtained from them would contain 1–10 wt% of pigmentation. Fibers formed out of modified solvents underwent spectral values, thermal, physicomechanical analyses, also their sorption features were evaluated. Copyright © 2007 John Wiley & Sons, Ltd.
A new copolymer membrane cured by 2‐hydroxy‐3‐phenoxypropylacrylate, 4‐hydroxybutyl acrylate, and isobutyl methacrylate controlled clonidine linear release in the transdermal drug delivery system
Authors: Zhan Xiaoping , Chen Sijing , Tang Guochun , Mao Zhenmin
Published: February 2007

The main objective of this present study was to synthesize a new type of copolymer membrane that presented a linear release property in clonidine transdermal drug delivery system. Three monomers, 2‐hydroxy‐3‐phenoxypropylacrylate, 4‐hydroxybutyl acrylate, and isobutyl methacrylate were treated under strong power UV radiation to prepare a new type of copolymer membrane. The effects of monomers' ratios, membrane thickness, and clonidine concentration on the permeation rates were investigated. It was discovered that the membrane controlled clonidine near zero‐order release. Furthermore, the membrane was characterized by FTIR, DSC, and SEM. Copyright © 2007 John Wiley & Sons, Ltd.