bluuebunny/crossref_metadata_2025_split huggingface dataset:
Clinical and biological behavior of pancreatic solid pseudopapillary tumors: Report on 31 consecutive patients
Authors: Salvia Roberto , Bassi Claudio , Festa Leonardina , Falconi Massimo , Crippa Stefano , Butturini Giovanni , Brighenti Antonietta , Capelli Paola , Pederzoli Paolo 
Published: February 2007

AbstractBackgroundSolid pseudopapillary tumors (SPTs) represent one of the most uncommon histotypes of all exocrine pancreatic neoplasms.AimTo delineate the clinical presentation and biological behavior of SPT and evaluate the efficacy of treatment.MethodsRetrospective analysis of 31 patients (27 female, 4 male, mean age of 34 years, (range 7–56)) who underwent surgical resection with a definitive histological diagnosis of SPT.ResultsTumor detection was incidental in the 55% of cases. Symptoms were abdominal discomfort (n = 10), jaundice (n = 2), weight loss (n = 6), vomiting (n = 5), and a palpable abdominal mass (n = 4). The neoplasm was localized in the pancreatic head in 10 patients and in the body‐tail in 20 cases; the main diameter ranged from 2 to 20 cm (mean 5.4). At the radiological work‐up, the neoplasm was solid in 87% of cases and delimited by a capsule in 39%. An internal necrotic‐hemorrhagic area was present in 29% of cases. Calcifications were noticed in two patients and septa in one. None of the patients had metastases at the time of diagnosis. In 9 cases, pancreaticoduodenectomy was performed, while 15 patients underwent a left pancreatectomy (4 spleen preserving), 6 a middle pancreatectomy, and 1 enucleation. There was no postoperative mortality with an overall morbidity of 35%. At a median follow‐up of 58.2 months (12–229 range), all patients are alive without evidence of local recurrence, metastasis, diabetes, or exocrine insufficiency.ConclusionsSolid pseudopapillary tumor (SPT) is an indolent neoplasm with low‐grade biological aggressiveness, making surgical treatment successful despite its large size. J. Surg. Oncol. 2007;95:304–310. © 2007 Wiley‐Liss, Inc.
Isocyanatoethyl Methacrylate Telomerization and Cotelomerization
Authors: Lam Ousmene A. , Hervaud Yves , Boutevin Bernard 
Published: February 2007

AbstractThis 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

AbstractThree 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

AbstractUsing 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

AbstractHighly 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
The paradox of inelastic sports pricing
Authors: Porter Philip K. 
Published: February 2007

AbstractRodney 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

AbstractOrganizational 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

AbstractThis 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

AbstractThe 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

AbstractCan 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

AbstractThe 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

AbstractRefraction 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

AbstractA 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

AbstractIn 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

AbstractA 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

AbstractA 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

AbstractIn 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

AbstractBased 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

AbstractThe 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

AbstractIn 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

AbstractIn 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

AbstractThis 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