bluuebunny/crossref_metadata_2025 huggingface dataset:
Parkinsonism and nigrostriatal dysfunction are associated with spinocerebellar ataxia type 6 (SCA6)
Authors: Khan Naheed L. , Giunti Paola , Sweeney Mary G. , Scherfler Christoph , Brien Michael O. , Piccini Paola , Wood Nicholas W. , Lees Andrew J.
Published: June 2005

SCA6 is a slowly progressive, late‐onset cerebellar ataxia due to a trinucleotide expansion in the CACNA1A gene. We describe two unrelated cases that presented with Parkinsonism and cerebellar ataxia. One case was L‐dopa–responsive with a pattern of 18F‐dopa uptake similar to Parkinson's disease, and the second case was not L‐dopa–responsive and had an atypical pattern of nigrostriatal dysfunction. We suggest that SCA6, in common with SCA2 and SCA3, may be associated with Parkinsonism attributable to nigral loss and dopaminergic dysfunction. Moreover, isolated cases may be confused with multiple system atrophy. © 2005 Movement Disorder Society
Interaction between blood lead concentration and δ‐amino‐levulinic acid dehydratase gene polymorphisms increases the odds of essential tremor
Authors: Louis Elan D. , Applegate LaKeisha , Graziano Joseph H. , Parides Michael , Slavkovich Vesna , Bhat Hari K.
Published: June 2005

Blood lead (BPb) concentrations are elevated in essential tremor (ET) cases. The δ‐amino‐levulinic acid dehydratase (ALAD) gene codes for ALAD, the principal enzyme involved in lead kinetics. Carriers of the ALAD‐2 allele may be more susceptible to lead toxicity. The objective of this study was to test, using a case‐control design, whether an interaction between BPb concentration and ALAD allele status increases the odds of ET. Mean log BPb concentration was significantly higher in 63 cases than 101 controls (0.47 ± 0.26 vs. 0.35 ± 0.25 μg/dl). Eighteen (28.6%) cases vs. 17 (16.8%) controls had an ALAD‐2 allele (OR = 1.98; 95% CI = 0.93–4.21). In an adjusted logistic regression analysis, the interaction term (ALAD allele status × log BPb concentration) was associated with increased odds for ET. In stratified analyses, log BPb concentration was not associated with odds of ET in individuals with two ALAD‐1 alleles (OR = 2.69; 95% CI = 0.61–11.82), but in individuals with an ALAD‐2 allele, BPb concentration was significantly associated with odds of ET (OR = 80.29; 95% CI = 3.08–2,096.36). There was an interaction between BPb concentration and ALAD allele status; the odds of ET were greatly elevated in individuals with both an ALAD‐2 allele and an elevated BPb concentration. The presence of increased circulating BPb concentrations along with a greater potential for lead toxicity (ALAD‐2 allele) could result in greater cerebellar damage, thereby increasing the risk of developing tremor. © 2005 Movement Disorder Society
Three brothers with a very‐late‐onset writer's cramp
Authors: Bhidayasiri Roongroj , Jen Joanna C. , Baloh Robert W.
Published: June 2005

Writer's cramp (WC) is a form of focal task‐specific dystonia, which is brought on by writing. Although most cases are sporadic, a positive family history is present in 5% to 20% of cases. To date, WC has been reported in several families with primary torsion dystonia, including DYT7, a pure focal dystonia, and in the mixed dystonias, DYT1, DYT6, and DYT13. We describe a family of Bulgarian descent with three brothers presenting with a very‐late‐onset dystonic WC, compatible with linkage to chromosome 18p. © 2005 Movement Disorder Society
Normalization of voice in spasmodic dysphonia during transient global amnesia
Authors: Kishore Asha , Lang Anthony E.
Published: June 2005

We report on the case of a 69‐year‐old woman with Parkinson's disease and long‐standing history of spasmodic dysphonia that reversed during an episode of transient global amnesia (TGA). To our knowledge, this phenomenon has not been reported before. We suggest possible mechanisms by which the pathophysiology of dystonia could reverse during TGA. © 2005 Movement Disorder Society
Heat‐related morbidity in patients with orthostatic hypotension and primary autonomic failure
Authors: Pathak Atul , Lapeyre‐Mestre Maryse , Montastruc Jean‐Louis , Senard Jean‐Michel
Published: June 2005

We investigated the effects of high‐external‐temperature exposure on neurogenic orthostatic hypotension (OH). Thirty‐one patients with autonomic failure (AF) and pharmacologically treated OH related to probable multiple‐system atrophy (n = 7), Parkinson's disease (n = 10), pure autonomic failure (n = 7), and diffuse Lewy body disease (n = 7) and 26 parkinsonians without AF were included. Prevalence and severity of clinical events were studied during the August 2003 heat wave and the 2004 summer. The prevalence of OH‐related events was significantly higher in 2003 [45.1 vs. 11.5%; P = 0.0052; OR = 6.31 (1.35–33.53)] and 2004 [42.3 vs. 12.0%; P = 0.014; OR = 5.40 (1.28–22.68)] in AF than in controls. The mean severity score for clinical events was significantly higher in AF than in controls during 2003 heat wave (1.2 ± 1.4 vs. 0.2 ± 0.5) but similar in summer 2004 (0.7 ± 1.0 vs. 0.1 ± 0.3). Severe events (unusual home care, assistance, or hospitalization) were only observed in AF patients. A nonstatistically significant higher prevalence of clinical events was observed in AF patients prescribed fludrocortisone (66.7%) by comparison to heptaminol (42.9%), midodrine (45.5%), or midodrine plus fludrocortisone (28.6%). This study shows that AF patients have a poor clinical outcome when exposed to high temperatures and that heat exposure is a risk factor for OH worsening. © 2005 Movement Disorder Society
Experimental verification of the possible range of linearization using a parallel diode
Authors: Yu Chi Sun , Mok Ka Tsun , Chan Wing Shing , Li Chung Wai
Published: June 2005

Linearization of a BJT using a diode configured in parallel with the input reduces 2nd‐order distortion. Using a simple behavioral model cannot explain why this reduces IMD3. The experimental work presented in this paper will verify the mechanism involved and the possible range for reducing IMD3by reducing the 2nd‐order effects. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 46: 193–195, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20942
Novel 3D Hilbert microstrip resonators
Authors: Crnojevic‐Bengin Vesna , Budimir Djuradj
Published: June 2005

Recently, planar microstrip resonators employing 2D Hilbert curves were introduced, outperforming existing solutions. However, very little attention has been paid to multilayer resonators with embedded 3D curves. In this paper, four novel 3D resonators are compared using full‐wave EM simulations. It is shown that the 3D Hilbert resonator outperforms all others, achieving very high values of the unloaded quality factor. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 46: 195–197, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20943
Novel dual‐broadband rectangular‐slot antenna for 2.4/5‐GHz wireless communication
Authors: Hsiao Hai‐Ming , Wu Jeun‐Wen , Wang Yau‐Der , Lu Jui‐Han , Chang Shun‐Hsyung
Published: June 2005

A novel design of rectangular slot‐antenna with dual‐broadband operation for 2.4/5‐GHz wireless local area networks (WLANs) is proposed. With the use of two rectangular strips inset along the center line of the rectangular‐slot antenna, a new resonant mode close to the second operating mode of the regular rectangular slot antenna is excited to enhance the operating bandwidth of the higher band. And, the obtained impedance bandwidths for two operating bands can reach about 11% for the 2.4‐GHz band and 24.8% for the 5‐GHz band and cover the required bandwidths of IEEE 802.11b/g (2.4–2.484 GHz) and IEEE 802.11a (5.150–5.950 GHz). Details of the antenna design and the experimental results are presented and discussed. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 46: 197–201, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20944
Numerical simulation of the microwave rewarming process of cryopreserved organs
Authors: Han X. , Gao D. Y. , Luo D. , Yu C. , Lu C. C.
Published: June 2005

The rewarming process of cryopreserved organs using microwave technology is analyzed by numerical simulation. The FDTD (finite‐difference time‐domain) method is applied to calculate the electromagnetic field in a real microwave rewarming system, composed by a cylindrical resonant cavity, an antenna source, and a frozen rabbit‐kidney phantom with temperature‐dependent properties. The efficiency of the FDTD codes is improved by nonuniform grid techniques and parallel algorithms. Meanwhile, an apparent specific‐heat method is introduced in the temperature‐field calculation. Coupling the solutions of the two fields is realized by a formerly developed algorithm. The numerical results show that in the rewarming process of the rabbit kidney phantom, the warming rate can reach 300°–500°C/min, which may prevent devitrification, but the maximum temperature difference in the sample (18 mm in radius) can reach 15°C at the end, which may cause severe thermal stress. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 46: 201–205, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20945
Steady‐state analysis of a directional square lattice band‐edge photonic crystal lasers
Authors: Cazo Rogério M. , Barbosa Carmem L. , Hattori Haroldo T. , Schneider Vitor M.
Published: June 2005

The original square‐lattice band‐edge structure emitted light in different directions. In a recent paper [18], we have improved the directivity of these structures by using a honeycomb photonic crystal to shield the original structure. This has improved the performance of such devices, in such a way that light can be coupled directionally to a large waveguide. In this paper, we present a steady‐state analysis of the performance of this directive device and study the amount of power which can be coupled into the waveguide, analyzing its performance as an in‐plane emitter and the limitations caused by vertical losses. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 46: 210–214, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20947
High‐gain printed dipole antenna
Authors: Liu Yung‐Tao , Tseng Ting‐Chih , Wong Kin‐Lu
Published: June 2005

A printed dipole antenna showing high gain (about 6.8 dBi) radiation in the azimuthal plane is presented. The dipole antenna has a narrow width of 10 mm and a total length of about 202 mm (with 1.64 wavelengths of the frequency at 2442 MHz, the center frequency of the 2.4‐GHz WLAN band). In each one of the two radiating arms of the dipole antenna, a meandered line is inserted as a phase‐reversal device. With this arrangement, the proposed dipole antenna performs as a collinear array antenna with three in‐phase half‐wavelength radiating elements, leading to constructive radiation in the azimuthal plane and small side lobes in the elevation plane. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 46: 214–218, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20948
Effects of dielectric width extension in a parallel‐plate Blumlein line
Authors: Joler Miroslav , Christodoulou Christos G. , Schamiloglu Edl , Gaudet John
Published: June 2005

Computational analyses are performed on a parallel‐plate Blumlein line with a nonstandard width of the dielectric, as a way to mitigate against the dielectric breakdown. We report its effects on the electric field, propagation time of the transient effect, characteristic impedance of the line, and output pulse. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 46: 220–225, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20950
Ultra‐short wavelength filters using mode‐related dispersion in dual‐mode waveguides
Authors: Tsai Tzong‐Yow , Lee Zhi‐Cheng , Chen Jong‐Rong , Chen Chi‐Chung , Fang Yen‐Cheng , Cha Ming‐Hong
Published: June 2005

An ultra‐short‐wavelength filter using photonic band gap (PBG) mode‐related dispersion in a two‐moded waveguide is proposed. It is verified using the finite‐difference time‐domain (FDTD) method, such that two channels on the PBG edges are affected by opposite dispersive effects and can be separated by an ultra‐short coupler length much shorter than the required length without the assistance of PBG dispersion. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 46: 225–227, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20951
Low‐profile omnidirectional circularly polarized antenna for WLAN access points
Authors: Hsiao Fu‐Ren , Wong Kin‐Lu
Published: June 2005

A novel low‐profile omnidirectional circularly polarized antenna comprising a top‐loaded cylindrical monopole and four printed arc‐shaped dipoles is presented. The cylindrical monopole and four printed dipoles share a common feeding point and generate two orthogonal polarizations with a 90° phase difference, resulting in omnidirectional circular‐polarization (CP) radiation in the azimuthal plane. The proposed antenna is also arranged in a compact structure with a low profile (less than 0.1 wavelength of the center operating frequency). A constructed prototype suitable for applications in a wireless local area network (WLAN) access point in the 2.4‐GHz band is demonstrated. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 46: 227–231, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20952
Superposition of mode coupling induced by dual acousto‐optic modulations
Authors: Tu Po‐Jen , Liu Wen‐Fung , Chen Tzu‐Chiang
Published: June 2005

The high‐order‐mode coupling of acousto‐optic modulations in a tilted fiber grating is experimentally demonstrated to be greatly enhanced due to the superposition of dual acousto‐optic‐modulations. The performance is based on the phase matching between two acousto‐optic‐modulations of different frequency in a fiber Bragg grating. The device can be applied in a switchable multiwavelength comb filter or a switchable multiwavelength fiber laser. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 46: 231–233, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20953
Analysis of circular patch antenna tuned by a ferrite post
Authors: Mavridis A. A. , Kyriacou G. A. , Sahalos J. N.
Published: June 2005

A circular patch antenna tuned by a ferrite post is presented. The DC‐biasing magnetic field is assumed perpendicular to the patch and the ferrite losses are taken into account. Both right‐ and left‐hand circular polarizations are considered. The “perfect magnetic walls” approximation is employed and the resulting closed‐form expressions can be used in the design of patch antennas. Also, this approximate but analytical study offers a clear physical insight with regard to the ferrite effects on the patch antenna's resonance characteristics. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 46: 234–237, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20954
Monopolar divergence‐conforming and curl‐conforming low‐order basis functions for the electromagnetic scattering analysis
Authors: Ubeda Eduard , Rius Juan M.
Published: June 2005

In this paper, we present two new sets of basis functions, which we name monopolar RWG and monopolar nxRWG. These sets are derived from the two conventional divergence‐conforming and curl‐conforming low‐order sets, RWG and nxRWG. For a wide variety of moderately small objects, we show the validity of the monopolar RWG and nxRWG Galerkin MoM‐MFIE discretizations. We show the performance improvement for the monopolar RWG MoM‐MFIE formulation with respect to the conventional choice and the robustness of both conventional and monopolar nxRWG MoM‐MFIE formulations © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 46: 237–241, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20955
A dual‐passband microstrip open‐loop resonator filter
Authors: Ahn Chang‐Soo , Lee Juseop , Kim Young‐Sik
Published: June 2005

In this paper, a design technique that includes a synthesis procedure and a realization method for a microstrip open‐loop resonator filter with two passbands is described. Transmission zeros of the filter‐transfer function are employed to split a single passband into two passbands, and the filter‐coupling structure used to realize two passbands is also given. The measured result shows good agreement with the synthesized one. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 46: 241–243, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20956
Fast analysis of optical waveguides using an improved Fourier series method with perfectly matched layer
Authors: Jia Hongting , Zhang Dan , Yasumoto Kiyotoshi
Published: June 2005

A fast method for analyzing optical waveguides with the use of an improved Fourier series method and an absorbing boundary condition of perfectly matched layer (PML) is proposed. The numerical examples show that the computing cost, calculated accuracy, and convergent speed with the PML condition have been saliently improved, as compared to without the PML condition. The validity of the proposed method have been confirmed via comparison with other methods and measurements. The proposed method can be easily extended to 3D problems. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 46: 263–268, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20961
Wideband slot antenna with a novel microstrip feed
Authors: Yao Feng‐Wei , Zhong Shun‐Shi , Wang Wei , Liang Xian‐Ling
Published: June 2005

A novel slot antenna of large bandwidth and small size, which is fed by a fan‐shaped microstrip feed with a straight stub, is introduced. The effect of the fan feed on the impedance characteristics is investigated theoretically and experimentally. Good agreement between the theoretical and experimental results is obtained. Its measured VSWR ≤ 2 bandwidth reaches approximately 114%, covering 1.55–5.66 GHz. The measured standing‐wave ratio curves and radiation patterns of the antenna at f = 2 GHz and at f = 5 GHz are both presented. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 46: 275–278, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20964
Microwave dielectric properties of marine DNA based polymers
Authors: Subramanyam Guru , Heckman Emily , Grote James , Hopkins Frank , Neidhard Robert , Nykiel Edward
Published: June 2005

Deoxyribonucleic acid (DNA)‐based polymer thin‐films are characterized at microwave frequencies. The dielectric properties of the films are extracted from comparison of the propagation constants of the co‐planar waveguide (CPW) lines on bare MgO substrates and the DNA‐based films on MgO substrates. The insertion loss introduced by an undoped DNA‐based polymer film is only 0.1 dB at 10 GHz and 0.5 dB at 30 GHz. A red‐dye‐doped DNA polymer film exhibited higher losses. The relative dielectric constant of the undoped DNA‐based film averages to 4 at microwave frequencies, and the loss‐tangent is below 0.1 up to 30 GHz. The dielectric properties of a 5% red‐dye‐doped DNA polymer film is compared to that of the pure DNA film. The DR1 doped DNA film exhibits 0.4‐dB higher loss at 10 GHz and 0.9‐dB higher loss at 30 GHz. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 46: 278–282, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20965
PBG‐assisted shared‐aperture dual‐band aperture‐coupled patch antenna for satellite communication
Authors: Karmakar Nemai C. , Mollah Md. N. , Padhi Shantanu K , Fu Jeffrey S.
Published: June 2005

Design and development of a photonic bandgap (PBG)‐assisted shared‐aperture dual‐band orthogonal aperture‐fed rectangular microstrip patch antenna element, which is suitable for a portable very small aperture terminal (VSAT), are presented in this paper. The dual‐band dual‐polarized antenna element achieves 21% input impedance bandwidth at the S‐ and C‐bands. A comparison of the antenna with and without 2D PBG grids shows that the inclusion of PBG structures (PBGSs) improves the antenna performances. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 46: 289–292, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20968
GPS/PCS dual‐band internal antenna with parasitic element
Authors: Harackiewicz Frances J. , Jung Byungwoon , Lee Byungje
Published: June 2005

A planar internal antenna for application in GPS/PCS dual‐band mobile phones is proposed and implemented. The proposed antenna has two resonant elements printed on a supporting FR4 substrate with thickness of 0.8 mm: one is the printed monopole element that radiates at a higher frequency and couples electromagnetically to the other element. The other is the printed dipole element that radiates at a lower frequency and is placed around the monopole element. In the proposed antenna, the most important design factor is the dimensional combination of the area occupied by each element so that the antenna provides a wide bandwidth of about 19% for GPS (1575 ± 10 MHz) and Korean PCS (1810 ± 60 MHz) bands, and a gain between −0.5 and 2 dBi for the operating band. The antenna design and experimental results from the actual phone are presented. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 46: 297–301, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20970
Wave representations for SPICE‐type circuit simulators
Authors: Huang Chien‐Chang
Published: June 2005

Due to the limitation of nodal‐voltage analysis, wave behaviors such as the S‐parameter representations of the RF/microwave circuits cannot be observed for SPICE‐type circuit simulators. This paper proposes a nodal formulation for the ideal directional coupler to separate the incident and reflected parts of the voltage so the reflection/transmission coefficients can be easily calculated, even in large‐signal conditions. Two simulation examples are given, including a band‐pass filter and a power amplifier in order to demonstrate the availability of the proposed method with confirmation from other microwave‐circuit software. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 46: 301–303, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20971
Erratum: A.E. Serebryannikov, "Mode mixing in an almost periodic azimuthally corrugated cavity," Microwave and Optical Technology Letters (2003) 37(6) 461–465
Authors: Serebryannikov A. E.
Published: June 2005

The original article to which this Erratum refers was published in Microwave and Optical Technology Letters (2003) 37(6) 461–465. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 46: 303, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20972
A hybrid genetic algorithm for the weight setting problem in OSPF/IS‐IS routing
Authors: Buriol L.S. , Resende M.G.C. , Ribeiro C.C. , Thorup M.
Published: June 2005

Intradomain traffic engineering aims to make more efficient use of network resources within an autonomous system. Interior Gateway Protocols such as OSPF (Open Shortest Path First) and IS‐IS (Intermediate System‐Intermediate System) are commonly used to select the paths along which traffic is routed within an autonomous system. These routing protocols direct traffic based on link weights assigned by the network operator. Each router in the autonomous system computes shortest paths and creates destination tables used to direct each packet to the next router on the path to its final destination. Given a set of traffic demands between origin‐destination pairs, the OSPF weight setting problem consists of determining weights to be assigned to the links so as to optimize a cost function, typically associated with a network congestion measure. In this article, we propose a genetic algorithm with a local improvement procedure for the OSPF weight‐setting problem. The local improvement procedure makes use of an efficient dynamic shortest path algorithm to recompute shortest paths after the modification of link weights. We test the algorithm on a set of real and synthetic test problems, and show that it produces near‐optimal solutions. We compare the hybrid algorithm with other algorithms for this problem illustrating its efficiency and robustness. © 2005 Wiley Periodicals, Inc. NETWORKS, Vol. 46(1), 36–56 2005
Competitive routing in multicast communications
Authors: Boulogne Thomas , Altman E.
Published: June 2005

We consider competitive routing in multicast networks from a noncooperative game theoretical perspective. There areNusers sharing a network, and each has to send a quantity of packets to a different set of addressees (each address must receive the same packets). To do this the user has only to send one copy of a packet, the network making the duplications of the packets at appropriate nodes (depending on the chosen trees). The routing choice of a user is how to split its flow between different multicast trees. We present different criteria for optimization of this type of game. We treat two specific networks and establish the uniqueness of the Nash equilibrium in these networks, as well as the uniqueness of link utilization at Nash equilibria for specific cost functions in networks with general topology. We also present a result for convergence to equilibria from an initial nonequilibrium state. © 2005 Wiley Periodicals, Inc. NETWORKS, Vol. 46(1), 22–35 2005
An approximation algorithm for Stackelberg network pricing
Authors: Roch Sébastien , Savard Gilles , Marcotte Patrice
Published: June 2005

We consider the problem of maximizing the revenue raised from tolls set on the arcs of a transportation network, under the constraint that users are assigned to toll‐compatible shortest paths. We first prove that this problem is strongly NP‐hard. We then provide a polynomial time algorithm with a worst‐case precision guarantee of ${{1 \over 2}\log_2 m_T+1}$, where mT denotes the number of toll arcs. Finally, we show that the approximation is tight with respect to a natural relaxation by constructing a family of instances for which the relaxation gap is reached. © 2005 Wiley Periodicals, Inc. NETWORKS, Vol. 46(1), 57–67 2005
Structured matrix methods for CAGD: an application to computing the resultant of polynomials in the Bernstein basis
Authors: Bini Dario A. , Gemignani Luca , Winkler Joab R.
Published: June 2005

We devise a fast fraction‐free algorithm for the computation of the triangular factorization of Bernstein–Bezoutian matrices with entries over an integral domain. Our approach uses the Bareiss fraction‐free variant of Gaussian elimination, suitably modified to take into account the structural properties of Bernstein–Bezoutian matrices. The algorithm can be used to solve problems in algebraic geometry that arise in computer aided geometric design and computer graphics. In particular, an example of the application of this algorithm to the numerical computation of the intersection points of two planar rational Bézier curves is presented. Copyright © 2005 John Wiley & Sons, Ltd.
Rational Krylov matrices and QR steps on Hermitian diagonal‐plus‐semiseparable matrices
Authors: Fasino Dario
Published: June 2005

We prove that the unitary factor appearing in the QR factorization of a suitably defined rational Krylov matrix transforms a Hermitian matrix having pairwise distinct eigenvalues into a diagonal‐plus‐semiseparable form with prescribed diagonal term. This transformation is essentially uniquely defined by its first column. Furthermore, we prove that the set of Hermitian diagonal‐plus‐semiseparable matrices is invariant under QR iteration. These and other results are shown to be the rational counterpart of known facts involving structured matrices related to polynomial computations. Copyright © 2005 John Wiley & Sons, Ltd.
Development and characterization of reactive extruded PVC/polyacrylate blends
Authors: Haba Y. , Narkis M.
Published: June 2005

This paper describes a method to obtain polymer blends by the absorption of a liquid solution of monomer, initiator, and a crosslinking agent in suspension type porous poly(vinyl chloride) (PVC) particles, forming a dry blend. These PVC/monomer dry blends are reactively polymerized in a twin‐screw extruder to obtain the in situ polymerization in a melt state of various blends: PVC/poly(methyl methacrylate) (PVC/PMMA), PVC/poly(vinyl acetate) (PVC/PVAc), PVC/poly(butyl acrylate) (PVC/PBA) and PVC/poly(ethylhexyl acrylate) (PVC/PEHA). Physical PVC/PMMA blends were produced, and the properties of those blends are compared to reactive blends of similar compositions.

Owing to the high polymerization temperature (180°C), the polymers formed in this reactive polymerization process have low molecular weight. These short polymer chains plasticize the PVC phase reducing the melt viscosity, glass transition and the static modulus. Reactive blends of PVC/PMMA and PVC/PVAc are more compatible than the reactive PVC/PBA and PVC/PEHA blends. Reactive PVC/PMMA and PVC/PVAc blends are transparent, form single phase morphology, have single glass transition temperature (Tg), and show mechanical properties that are not inferior than that of neat PVC.

Reactive PVC/PBA and PVC/PEHA blends are incompatible and two discrete phases are observed in each blend. However, those blends exhibit single glass transition owing to low content of the dispersed phase particles, which is probably too low to be detected by dynamic mechanical thermal analysis (DMTA) as a separate Tg value. The reactive PVC/PEHA show exceptional high elongation at break (∼90%) owing to energy absorption optimized at this dispersed particle size (0.2–0.8 µm). Copyright © 2005 John Wiley & Sons, Ltd.
Exploring the effect of transient exposure on the risk of acute events by means of time‐window designs: an application to fluoroquinolone antibacterials and arrhythmia
Authors: Corrao Giovanni , Botteri Edoardo , Bertù Lorenza , Zambon Antonella , Favilli Sergio
Published: June 2005

Purpose

To compare different strategies in allocating time‐window at risk and in choosing optimal comparator in the setting of proarrhythmic effects of antibacterial fluoroquinolones.

Design

A population‐based cohort study.

Setting

Resident population of a Northern Italian Province.

Participants

The study cohort comprised 75 226 patients who received at least one prescription for fluoroquinolone from 1997 to 1999. Cohort members who experienced at least an antiarrhythmic drug prescription and/or hospitalisation with diagnosis of arrhythmia during the follow‐up were identified.

Analysis

Trends in incidence rates of arrhythmia according to different strategies in allocating time‐windows at risk were calculated. Standardised incidence ratios were obtained by comparing arrhythmic events experienced by the study cohort during the time‐windows at risk with those expected from both external (unexposed target population) and internal (study cohort during reference time‐windows) comparators.

Results

The rate of arrhythmia was 21.0 per 100 000 person‐weeks during the in‐treatment period, remained stable during the following week, and progressively decreased until to converge to 7.7 per 100 000 person‐weeks from 16th weeks after stop of exposure. Standardised incidence ratios were 2.35 (95%CI: 1.82, 2.99) and 1.86 (1.44, 2.37) according to external and internal comparators respectively. Evidence of linear increasing of proarrhythmic effect with the length of the antibacterial therapy appeared from every approaches, but it was stronger by using internal comparator.

Conclusions

Time‐windows designs should be performed by allocating the time‐windows at risk and comparing outcome events observed in the cohort during these periods with those experienced by the same cohort during an adequate reference period. Copyright © 2005 John Wiley & Sons, Ltd.
Front Cover: Plasma Process. Polym. 5/2005
Authors: Förch Renate , Zhang Zhihong , Knoll Wolfgang
Published: June 2005

Front Cover: During the plasma‐on phase of pulsed plasma deposition reactions, the surface is subjected to a highly reactive mixture of species and UV‐irradiation leading to a combination of surface modification, deposition and ablation processes. When the plasma is turned off, the ions, metastables and electrons disappear due to relaxation processes, leaving behind only long lived radicals, which can undergo radical polymerisation reactions. Careful adjustment of the plasma process conditions allows for a significant control over the chemical structure and cross link density of the deposits. When swollen in aqueous solution, low cross linked functionalized plasma polymer films behave as 3‐dimensional surfaces and enable the binding of molecules within the polymer network. Further details can be found in the Feature Article by R. Förch,* Z. Zhang, and W. Knoll on page 351.
Back Cover: Plasma Process. Polym. 5/2005
Authors: Xu Shuyan , Long Jidong , Sim Lina , Diong Cheong Hoong , Ostrikov Kostya (Ken)
Published: June 2005

Back Cover: The picture, based on the research results of the team of the Plasma Sources and Applications Center of Nanyang Technological University, Singapore, shows four steps of plasma‐aided fabrication and performance assessment of biocompatible HA coatings of Ti6A14V orthopedic implant alloy material. Top left: Plasma glow in the process of concurrent Rf magnetron sputtering of HA and Ti targets. Top right: Surface morphology of the HA coating under optimized process conditions. Bottom left: SEM showing that apatite regrowth after immersion of the HA‐coated Ti6A14V samples in the simulated body fluid is accompanied by the formation of a complex granular network. Bottom right image: Surface of the HA‐coated sample covered by differentiated osteoblast cells during the cell culture assessment. Further details can be found in the Feature Article by S. Xu,* J. D. Long, L. Sim, C. H. Diong, and K. Ostrikov on page 373.
Delay of coupling caused by excess additives
Authors: Nozaki Sukekatsu
Published: June 2005

Use of excess quantity of additives such as 1‐hydroxybenzotriazole, 1‐hydroxy‐7‐azabenzotriazole, or 3,4‐dihydro‐3‐hydroxy‐4‐oxo‐1,2,3‐benzotriazine could retard carbodiimide‐mediated peptide coupling or aminolysis of the active esters in organic solvents generally employed in peptide chemistry. Solubility test and infrared spectroscopic data suggested that the amine components interacted with the additives to form some aggregates, which were less reactive toward acylation. The use of 0.1 equimolar additives against carboxyl components or carbodiimides was advantageous for rapid and efficient coupling reaction, especially when the carboxyl components were amino acids carrying urethane type N‐protecting groups. Copyright © 2005 European Peptide Society and John Wiley & Sons, Ltd.
A theoretical study of pentacyclo‐undecane cage peptides of the type [Ac‐X‐Y‐NHMe]
Authors: Bisetty Krishna , Corcho Francesc J. , Canto Josep , Kruger Hendrik G. , Perez Juan J.
Published: June 2005

The conformational preferences of peptides of the type, Ac‐X‐Y‐NHMe, where X and Y = Ala, cage and Pro, were studied by means of computational techniques within the framework of a molecular mechanics approach. For each of the eight peptide analogues, extensive conformational searches were carried out using molecular dynamics (MD) and simulated annealing (SA) protocols in an iterative fashion. Both results are in good agreement and complement each other. The conformational search indicates that the cage residue restricts the conformational freedom of the dipeptide considerably in comparison with the other model residues used. This study revealed that proline exhibits a greater tendency in promoting reverse‐turn characteristics in comparison to the cage peptides, which show promising β‐turn characteristics. It was also found that 300–500 K is not sufficient to overcome rotational barriers for cage peptides. In all cases, the low‐energy conformers have a tendency to form bent structures. Copyright © 2005 European Peptide Society and John Wiley & Sons, Ltd.
A multi‐Debye relaxation model for relaxor ferroelectrics showing diffuse phase transition
Authors: Peláiz‐Barranco A. , García‐Zaldívar O. , Calderón‐Piñar F. , López‐Noda R. , Fuentes Betancourt J.
Published: June 2005

The relaxor ferroelectrics showing diffuse phase transition (DPT) are promising materials for multilayer ceramic capacitors because of their high dielectric permittivity in the vicinity of the so called DPT. This physical parameter is also important in the fine piezoelectric, pyroelectric and electro optic performance of relaxor ferroelectrics. The dielectric behavior of these materials shows that the ferroelectric–paraelectric transition is diffuse. Also, there is a frequency dispersion of the real and imaginary parts of the dielectric permittivity and a deviation from the Curie–Weiss law. Many models have been developed to explain this phenomenon, but the exact mechanism associated to this dielectric behavior has not been established yet. This paper presents an analysis of the dielectric behavior in PLZT ferroelectric ceramics by using a new multi‐Debye relaxation model, which does not make assumptions that involve the microstructure or possible correlation mechanisms. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Few particles correlation in a one‐dimensional quasiperiodic lattice
Authors: Suárez J. R. , Vallejo E. , Carvajal E. , Navarro O.
Published: June 2005

During the last two decades, two of the most important discoveries in condensed matter physics have been the discovery of quasicrystals and the discovery of high‐Tc ceramic superconductors. These topics have generated a large number of experimental and theoretical studies in the physics of low dimension. They have also modified some of the concepts in solid state physics. For instance, it was believed that the five‐fold symmetry was incompatible with a long‐range order and it was not expected that ceramic materials with a high‐Tc and a short coherence length exhibit superconductivity. Therefore, it is important to revise both the spatial symmetry and the electronic correlation to identify how they affect the physical properties of materials. The study of these subjects is complex since we cannot use the reciprocal space to study quasicrystals and the electronic correlation in many‐body systems has not entirely been solved. Even in one‐dimensional quasiperiodic structures, the interactions between electrons have often been neglected and only few results have been obtained. In this work, we solved the cases of two and three interacting particles in a Fibonacci lattice using a real‐space method, the Green function technique, the renormalized perturbation expansion method and the Hubbard model. For the case of two interacting particles an analytical solution for the pairing phase diagram was obtained using the extended Hubbard Hamiltonian. For the case of three interacting particles the binding energy was numerically calculated. The results present here are compared with those obtained for the periodic and binary lattices. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Nanostructured Y0.5Pr0.5Co5 powders produced by high energy mechanical milling
Authors: Sánchez J. L. , Sánchez Valdés C. F. , Torres‐Moye E. , Villa C. A.
Published: June 2005

Highly coercive isotropic nanostructured powders based on alloys with the starting composition Y0.5Pr0.5Co5 were obtained by high energy mechanical milling of as‐cast alloys during 4 hours followed by annealing in high vacuum at 1073 K for 1 minute. X‐ray diffraction analysis, transmission electron microscopy observations and magnetic measurements show that a single phase with CaCu5‐type structure (a = 0.4935 nm, c = 0.4038 nm), showing a fine very uniform microstructure with an average grain size of 9.2 nm, room temperature intrinsic coercivity of 1.09 MA/m and remanence ratio of 0.68, is obtained in annealed powders. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Ab‐initio study of excitonic effects in conventional and organic semiconductors
Authors: Hummer K. , Ambrosch‐Draxl C. , Bussi G. , Ruini A. , Caldas M. J. , Molinari E. , Laskowski R. , Christensen N. E.
Published: June 2005

The excitonic effects on the optical absorption properties of organic semiconductors as well as gallium nitride are studied from first‐principles. The Coulomb interaction between the electron and the hole is accounted for by solving the two‐particle Bethe–Salpeter Equation. In the organic semiconductors the exciton binding energies strongly depend on the molecular size, the crystalline packing, as well as the polarization direction of the incoming light. We show that the electron–hole interaction can lead to strongly bound excitons with binding energies of the order of 1 eV or to a mere redistribution of oscillator strength. In several cases, the screening is efficient enough such that free charge carriers govern the optical absorption process. In the inorganic counterparts the sensitivity of the exciton binding energy is tested against the structural parameters and the screening of the electron–hole Coulomb interaction. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Development of a useful technique for analyzing behavioral teratologic data
Authors: Jensh R. P. , Brent R. L.
Published: June 2005

Two measures of postnatal development are described in this paper: the PAC50 and AD50. These measures proved to be more sensitive than the use of means in the evaluation of three radiation studies involving postnatal developmental evaluation. PAC50 is the percent of achievement of a goal by litters or offspring in an experimental group at the age when 50% of the control litters or offspring in each group attain that goal. AD50 is the age (acquisition day) at which 50% of the litters or offspring in each group attain a specified developmental goal. This methodology is a useful technique for analyzing selected behavioral data following in utero X‐irradiation and may prove to be a sensitive means of determining postnatal alteration due to prenatal exposure to a variety of suspect agents.
Lack of lead effects on fetal development and offspring learning when combined with alcohol in the long‐evans rat
Authors: Zajac C. S. , Abel E. L.
Published: June 2005

Two studies were conducted to evaluate the interactive effects of alcohol and lead during pregnancy in rats. Our purpose was to see if lead, as lead acetate, would influence the alcohol effect already known to exist. In the first study, pregnant Long‐Evans rats received lead (as lead acetate), alcohol (20% w/v), or lead plus alcohol once a day on gestation days (GD) 10–20. On GD 20, when animals were sacrificed, mean blood alcohol levels were consistently higher for the lead‐plus‐alcohol‐dosed groups compared to alcohol alone, but these two groups did not differ in maternal weight gain, percent resorptions, litter size, or fetal weight. Mean blood lead levels were not consistently higher in the lead‐plus‐alcohol groups compared to lead only, but the lead‐plus‐alcohol groups differed significantly from the lead‐only groups at higher doses in the previously mentioned parameters. The lead‐only groups did not differ from vehicle controls in any parameter in spite of blood lead levels as high as 300 μg/dl.

In the second experiment, animals given a combination of alcohol and lead did not differ in activity, passive avoidance, or active avoidance learning compared to animals given alcohol or lead alone: Animals given lead only or the combination of lead plus alcohol had longer first trial latencies in the passive avoidance test.

The data indicate that neither lead nor alcohol attenuates or potentiates each other's effects on reproduction or learning behavior in the Long‐Evans rat even at high blood lead levels.
Inhibitory effects of cobalt chloride and cinnamaldehyde on 5‐azacytidine‐induced digital malformations in rats
Authors: Kurishita Akihiro , Ihara Toshio
Published: June 2005

The effect of two DNA repair inhibitors in bacteria, cobalt chloride and cinnamaldehyde, on 5‐azacytidine (5‐AC)‐induced digital malformations was studied. Both agents inhibited the induced digital malformations. The effect of cobalt chloride was significant 3 hr before to 1 hr after the 5‐AC treatment, and the effect of cinnamaldehyde was significant 3 hr before to 24 hr after the treatment. However, an increase in fetal mortality was observed with the latter agent. The mechanisms underlying the suppressive effects of both agents may be different, but their natures require elucidation.
Ectopia cordis in the chick embryo heart: An experimental study
Authors: Jaffee Oscar C. , Jaffee Andrew L.
Published: June 2005

Ectopia cordis was observed during a study on the effects of a calcium antagonist (verapamil) on chicken embryo heart development. Experimental procedures, carried out at 60 hours of incubation, included placement of windows in eggs, injection of verapamil or saline, and the removal of ovalbumen from eggs. Fluid removal caused a downward displacement of the embryo and helped separate the embryo and its membranes from the shell membranes. Ectopia cordis was only observed in experiments involving fluid removal. One exception, the appearance of one ectopic heart in a window‐only experiment (no fluid removed), remains unexplained. The movements of fluids, brought about by the withdrawal of ovalbumen from eggs, and the subsequent effects of such movements on the positioning of embryos seemed to be the most important factor in the genesis of ectopia cordis. Also observed in fluid removal experiments were asymmetric circulations, abnormal embryonic flexion, and several embryos whose positions were rotated. These abnormalities were probably related to fluid removal and/or ectopia cordis.
Protein alterations associated with N‐methyl‐N‐nitrosourea exposure of preimplantation mouse embryos transferred to surrogate mothers
Authors: Bossert Nancy L. , Hitselberger M. Helen , Iannaccone Philip M.
Published: June 2005

Mouse preimplantation embryo functions have been shown to be disrupted by in vitro exposure to N‐methyl‐N‐nitrosourea (MNU) with subsequent transfer to the uteri of pseudopregnant surrogate mothers. Increased gross malformations and decreased fetal body lengths in the midgestational period have been previously documented. Protein extracts were isolated from day 12 mouse fetuses developed from MNU‐ or solvent‐exposed blastocysts and analyzed by two‐dimensional electrophoresis. The electrophoretic patterns reveal six protein alterations in day 12 fetal tissue induced by MNU treatment at the blastocyst stage. Five of these alterations involve shifts in isoelectric point (pI) and the other alteration involves a quantitative increase in a protein. The possibility that two of the proteins which exhibit a shift in pI following MNU exposure represent the cell adhesion molecules, N‐CAM and L‐CAM (based on similar Mr values), was investigated by Western blot analysis. No pI alteration in L‐CAM or N‐CAM expression is seen after MNU exposure. These results demonstrate that in vitro MNU exposure of preimplantation embryos results in protein alterations in midgestational fetuses. Thus, the effects of MNU exposure on preimplantation embryos may be manifest long after exposure, and subtle, non‐lethal mutations may play a role in poor fetal outcome after early chemical exposure.