bluuebunny/crossref_metadata_2025 huggingface dataset:
Unclassifiable parkinsonism in two European tertiary referral centres for movement disorders
Authors: Katzenschlager Regina , Cardozo Adriana , Avila Cobo M. Rosario , Tolosa Eduardo , Lees Andrew J.
Published: October 2003

In view of reports on high frequencies of atypical parkinsonism from different parts of the world and in non‐white communities in the United Kingdom, we have prospectively surveyed 1,000 consecutive patients with parkinsonism presenting to two European tertiary referral centres for movement disorders (London, UK, and Barcelona, Spain). The aims of our study were to assess in a cross‐sectional, prospective manner the proportion of patients who could not be classified diagnostically, to identify the factors precluding classification, and to determine which diagnostic measures would increase the rate of classifiable cases. Diagnoses were established using published clinical diagnostic criteria for Parkinson's disease (PD) and for other conditions associated with parkinsonism. Twenty‐nine patients in London and 25 in Barcelona were initially considered unclassifiable; nine could be classified after further investigations. Levodopa (L‐dopa) responsiveness was found to have a pivotal role in establishing a clinical diagnosis in previously unclassifiable patients: In those 45 patients who remained unclassifiable, failure to respond to L‐dopa without other exclusion criteria for PD was the most common finding in each centre. Our results show that 4.0 to 5.0% of parkinsonian patients presenting to specialist clinics in Western Europe cannot be categorised using currently available clinical diagnostic criteria for parkinsonian syndromes. Prolonged follow‐up and neuropathological diagnosis will be needed to determine whether all these cases represent atypical presentations of established clinico‐pathological entities or whether some represent unrecognised new disorders. © 2003 Movement Disorder Society
Is the target for thalamic deep brain stimulation the same as for thalamotomy?
Authors: Kiss Zelma H.T. , Wilkinson Marshall , Krcek Jerry , Suchowersky Oksana , Hu Bin. , Murphy William F. , Hobson Doug , Tasker Ron R.
Published: October 2003

Deep brain stimulation (DBS) has virtually replaced thalamotomy for the treatment of essential tremor. It is thought that the site for DBS is the same as the optimal lesion site; however, this match has not been investigated previously. We sought to determine whether the location of thalamic DBS matched the site at which thalamotomy would be performed. Eleven patients who had detailed microelectrode recording and stimulation for placement of DBS electrodes and subsequent successful tremor control were analysed. An experienced surgeon, blinded to outcome and final electrode position, selected the ideal thalamotomy site based on the reconstructed maps obtained intraoperatively. When the site of long‐term clinically used DBS and theoretical thalamotomy location was calculated in three‐dimensional space and compared for each of the x, y, and z axes in stereotactic space, there was no significant difference in the mediolateral location of DBS and theoretical lesion site. There was also no difference between the theoretical lesion site and the placement of the tip of the electrode; however, the active electrodes used for chronic stimulation were significantly more anterior (P = 0.005) and dorsal (P = 0.034) to the ideal thalamotomy target. This mismatch may reflect the compromise required between adverse and beneficial effects with chronic stimulation, but it also suggests different mechanisms of effect of DBS and thalamotomy. © 2003 Movement Disorder Society
Abnormal corticomuscular coherence is associated with the small amplitude cortical myoclonus in Parkinson's disease
Authors: Caviness John N. , Adler Charles H. , Sabbagh Marwan N. , Connor Donald J. , Hernandez Jose L. , Lagerlund Terrence D.
Published: October 2003

Coherence is the degree of time‐locked correlation between two signals as a function of frequency. The purpose of this study was to test the following hypotheses: (1) corticomuscular coherence is abnormally increased in those Parkinson's disease (PD) patients with small amplitude cortical myoclonus, and (2) corticomuscular coherence peaks around the time of the myoclonus electromyographic (EMG) discharge. We studied Parkinson's disease patients with and without myoclonus and controls. The data were digitally collected and processed off‐line with EMG rectification, creation of 511‐msec epochs, Fast‐Fourier transform, and coherence analysis. In the 12 to 30 Hz frequency band, but not at 30 to 60 Hz or above, coherence peaks were observed in the PD subjects with myoclonus that were significantly greater than in the control subjects (P < 0.001) and in PD subjects without myoclonus (P < 0.001). The abnormal coherence values are evidence for abnormal rhythmic activity in cortical motor areas in those Parkinson's disease patients with myoclonus. In combination with previous findings on back‐averaging, our results show that this myoclonus occurs when neuronal populations are driven to an extreme amount of synchronous activity with higher corticomuscular coherence values. These results have mechanistic implications for cortical dysfunction in Parkinson's disease and for cortical myoclonus in general. © 2003 Movement Disorder Society
Severe generalized dystonia as a presentation of a patient with aprataxin gene mutation
Authors: Sekijima Yoshiki , Hashimoto Takao , Onodera Osam , Date Hidetoshi , Okano Tomomi , Naito Kosuke , Tsuji Shoji , Ikeda Shu‐ichi
Published: October 2003

A 14‐year‐old girl, homozygous for an insertion mutation of aprataxin (APTX), 689 ins T, is described. She presented with severe generalized dystonia, ataxia, ocular motor apraxia, and areflexia. The dystonia of this patient suggests involvement of the basal ganglia or thalamus, along with clinical diversity in this disorder. © 2003 Movement Disorder Society
Developments in the molecular biology of DYT1 dystonia
Authors: Walker Ruth H. , Shashidharan P.
Published: October 2003

The identification of a mutation of the DYT1 gene as a cause of inherited dystonia has led to many insights regarding the genetics of this disorder. In addition, there is a rapidly expanding list of inherited dystonia syndromes, the genes for some of which have been identified or localized. The DYT1 mutation has been found in a variety of ethnic groups, and it may result in a range of phenotypes. To date, studies of torsinA, the protein product of the DYT1 gene, have not revealed its function, although its widespread distribution throughout the central nervous system suggests a universal role. TorsinA has structural homology to heat shock and chaperone proteins. Evidence from studies in cell cultures and Caenorhabditis elegans, and the presence of torsinA in inclusion bodies in several neurodegenerative diseases may be indicative of a function of this nature. Preliminary studies in humans with DYT1 dystonia and in DYT1 transgenic mice suggest disruption of the dopaminergic nigrostriatal system. A functional interference with neuronal signal processing induced by mutation of torsinA is consistent with current hypotheses regarding impairment of the center‐surround mechanism in the striatum. © 2003 Movement Disorder Society
Treatment of hypophonia with collagen vocal cord augmentation in patients with parkinsonism
Authors: Hill Amy N. , Jankovic Joseph , Vuong Kevin D.A.T. , Donovan Don
Published: October 2003

We conducted structured interviews of patients with Parkinson's disease (PD) and other parkinsonian disorders and their caregivers after augmentation of vocal folds with collagen injections. A total of 12 patients (mean age, 73.7 ± 8.6 years) completed the questionnaire after an average of 3.0 ± 1.7 collagen injections, with an average of 13.8 ± 7.4 weeks between each injection. In addition to improvement in all six voice quality questions, there was significant improvement (P < 0.05) in the Glascow Benefit Inventory (GBI) score. The injection procedure was tolerated well by patients with an average duration of benefit lasting 7.8 ± 8.5 weeks. Augmentation of vocal folds with collagen provides temporary improvement in voice in patients with parkinsonian hypophonia. © 2003 Movement Disorder Society
CPW balanced amplifier with a new branch‐line coupler
Authors: Yun Bub‐Sang , Yun Tae‐Soon , Lee Jong‐Chul , Kim Jong‐Heon , Lee Byungje , Kim Nam‐Young , Park Hyun‐Chang
Published: October 2003

In this paper, a balanced amplifier with coplanar waveguide structure for wireless LAN applications is presented. To reduce the input VSWR and improve stability, the balanced characteristic is adopted for the amplifier's design. The balanced amplifier is designed by several microwave simulation tools, such as Agilent ADS ver. 1.3, Agilent HFSS ver. 5.6, IMST COPLAN ver. 2.3, and Zeland IE3D ver. 8.0. The new branch‐line coupler shows an insertion loss of 3.5 dB and input/output return losses of greater than 20 dB at 5.8 GHz. The balanced amplifier, using a new CPW branch‐line coupler, shows a gain of about 10 dB at 5.8 GHz. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 39: 349–351, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11213
Harmonic suppression in microstrip multistage coupled‐ring bandpass filters using defected ground structures
Authors: Griol A. , Mira D. , Marti J. , Corral J. L.
Published: October 2003

The introduction of defected ground structures (DGSs) in microwave bandpass filters, based on microstrip coupled‐ring resonators to suppress higher harmonics, is investigated. Two topologies based on placing DGS units into and out of the coupled rings are considered and investigated. Harmonic suppression ratios for the second harmonic greater than 20 dB in a flat bandpass filter centered at 2.25 GHz are achieved for both structures. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 39: 351–354, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11214
An EM‐coupled dual‐polarized microstrip patch antenna for RFID applications
Authors: Padhi S. K. , Karmakar N. C. , Law C. L.
Published: October 2003

This paper presents the design and development of a compact dual linearly polarized aperture‐coupled microstrip patch antenna array system for radio frequency identifications (RFID) applications. Two different antenna designs, Antenna‐1 and Antenna‐2, for RFID tag and reader applications are presented at the C and S bands, respectively. The antennas use two symmetric coupling apertures to excite two orthogonal modes for dual‐polarization operation. High isolation of the order of −35 dB is obtained by proper selection of the shape and positions of the coupling aperture. The prototype antenna yields a 14.6‐dBi peak gain, a 36° 3‐dB beamwidth (HPBW), a 30‐dB cross‐polarization level, and isolation better than 38 dB between the two orthogonal polarizations (Tx and Rx) at the S band, and a 7.7‐dBi peak gain, a 70° 3‐dB beamwidth (HPBW), a 24‐dB cross‐polarization level, and isolation better than 38 dB between the orthogonal polarization at the C‐band, respectively. The antenna yields a 10‐m identification‐read range in the field trial. The findings are very promising for RFID applications. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 39: 354–360, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11215
2 × 2 Circularly polarized patch antenna arrays with broadband operation
Authors: Wu Jeun‐Wen , Lu Jui‐Han
Published: October 2003

By adopting a sequential rotation technique with the use of an L‐strip microstrip line to feed the proposed patch antenna array, a broadband design for circular polarization (CP) is proposed and experimentally studied. The impedance bandwidth and 3‐dB axial‐ratio bandwidth of the circularly polarized patch antenna arrays presented achieve a 46.8% and 45%, respectively. The measured minimum axial ratio is 0.5 dB for the truncated‐corner square‐patch antenna array operating at 1.4 GHz. Peak antenna gain across the overall operating band is measured to be 10.5 dBi. Details of the proposed broadband circular‐polarization design are described, and experimental results of the constructed prototypes are presented and discussed. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 39: 360–363, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11216
Determination of optimal pumping configuration for an L‐band EDFA with 980‐nm LD and ASE pumps
Authors: Adikan F. R. M. , Mahdi M. A. , Noor A. S. M.
Published: October 2003

L‐band gain improvement through amplified spontaneous emission (ASE) pumping was conducted. For an L‐band amplifier system employing ASE to improve gain, pumping the system counterdirectionally with ASE and codirectionally with 980 nm would yield the best overall performance in terms of gain. Gain improvement as high as 6 dB was attained. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 39: 363–366, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11217
Small chip dielectric antenna for Bluetooth application
Authors: Moon Jung‐Ick , Park Seong‐Ook
Published: October 2003

This paper proposes the design of a small chip‐type dielectric antenna using the advanced meander line technique, so that the radiation metals are formed on the bottom face of a ceramic dielectric (8 × 4 × 1.5 mm3, alumina) and on both faces of the substrate (thickness 1.0 mm, FR‐4). The performance of the proposed antenna mode, which remarkably reduced the size, shows good agreement between measured and computed results. The measured results show that this antenna has 11.2% bandwidth (2.35–2.63 GHz, |S11| < −10 dB) and 2.3‐dBi maximum radiation gain, respectively. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 39: 366–368, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11218
Planar‐diversity folded‐dipole antenna for 5‐GHz WLAN operation
Authors: Lee Gwo‐Yun , Chen Wen‐Shyang , Wong Kin‐Lu
Published: October 2003

A novel planar‐diversity folded‐dipole antenna, comprising two back‐to‐back folded dipoles separated by a central ground plane, is proposed. Experimental results of a constructed prototype suitable for WLAN operation in the 5‐GHz band, such as the 5.2‐GHz (5150–5350 MHz) and 5.8‐GHz (5725–5875 MHz) bands are presented. The radiation patterns of the two folded dipoles are directional in two complementary half spaces, and thus are capable of providing spatial diversity in order to mitigate the multipath interfering problem for WLAN operation. Details of the antenna design and experimental results are presented. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 39: 368–370, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11219
A stair‐shaped slot antenna for the triple‐band WLAN applications
Authors: Wang Chien‐Jen , Tsai Wen‐Tsai
Published: October 2003

In this paper, a novel triple‐band microstrip‐fed slot antenna for wireless communication systems operating at 2.4, 5.2, and 5.8 GHz is demonstrated. The slot antenna is originally designed to radiate at 2.4 GHz. By etching a stair‐shaped slot on the ground plane and adding several stubs at the edge to excite the first higher‐order mode, we can create another resonant band at 5 GHz. According to the results, the impedance bandwidths are 227 and 778 MHz at the 2.4‐ and 5‐GHz bands, respectively. In addition, the dimension of the proposed slot antenna is smaller than that of the conventional rectangular‐slot antenna. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 39: 370–372, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11220
A method for characterizing coplanar waveguide‐to‐microstrip transitions, and its application to the measurement of microstrip devices with coplanar microprobes
Authors: Maya M. C. , Lázaro A. , DePaco P. , Pradell L.
Published: October 2003

This paper presents a method for characterizing coplanar waveguide‐to‐microstrip (CPW‐M) transitions by using on‐wafer coplanar (CPW) microprobes. It is based on extracting the transmission matrix of the CPW‐M transition from the measurement of theSparameters of two microstrip transmission lines of different lengths, each of which includes two CPW‐M transitions. To verify the proposed method, theSparameters of a zero‐length line, which is composed of two CPW‐M transitions (“thru” connection) and has not been used in the transition characterization, are measured up to 40 GHz and are compared to those extracted and obtained from electromagnetic simulations. The method is applied to the measurement of a microstrip coupled‐line filter embedded in CPW‐M transitions. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 39: 373–378, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11222
An iterative method for solving a large dense matrix in the method of moments solution of an electrostatic problem
Authors: Singh Ritu , Singh Surendra
Published: October 2003

This paper illustrates the application of Wynn's vector ε‐algorithm to solve a system of equations arising in the method of moments (MoM) solution of an electrostatic problem. Since the method is iterative, it does not require inversion of a matrix. The degree of accuracy of the solution can be controlled by specifying a convergence factor. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 39: 378–380, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11223
Configuration of a stepped impedance bandpass filter
Authors: Wang Xuedong , You Bin , Ji Wusheng , Li Ying
Published: October 2003

This paper describes the design of a compact stripline ceramic filter, using short‐circuit stepped‐impedance resonators (SIRs) to enhance the harmonic stop‐band response. Moreover, this filter has a very small size of 3.6 mm × 3.0 mm × 0.5 mm and a low insertion loss of 0.6 dB in the passband. The filter's response, with a design center frequency of 2390 MHz and 3‐dB bandwidth at 250 MHz (10.4%), shows an increase in the first harmonic frequency to 9004 MHz. At three times the fundamental passband frequency (7160 MHz), stop‐band attenuation is better than −40 dB. The results demonstrate the usefulness of SIRs for improving the stop‐band performance of bandpass filters. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 39: 380–383, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11224
Simple models based on neural networks for suspended and inverted microstrip lines
Authors: Yildiz Celal , Saracoglu Oytun
Published: October 2003

This paper presents new and simple models based on artificial neural networks (ANNs) to determine the effective permittivities of suspended microstrip (SM) and inverted microstrip (IM) lines. The neural results are in very good agreement with the theoretical and experimental results available in the literature for both SM and IM lines. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 39: 383–389, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11225
Smart planar inverted‐F antenna for broadband applications
Authors: Karmakar Nemai Chandra
Published: October 2003

A single‐feed dual‐band stacked‐patch Planar Inverted‐F Antenna (PIFA) is integrated with a RF switch array at one side of its shorting straps to make a tunable PIFA. The L‐band switch yields 0.45‐dB insertion loss (IL) and 10‐dB isolation bandwidth (BW) of >100% at 1.2 GHz. The tunable PIFA yields 13% frequency tunability BW at 800 MHz band and 21% BW at the 1.9‐GHz band. The measured radiation patterns are broad beams with low backlobes, as compared to those of a standard PIFA. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 39: 389–393, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11226
Near‐field time‐domain physical‐optics and FDTD method for safety assessment near a base‐station antenna
Authors: Martínez‐Búrdalo M. , Nonídez L. , Martín A. , Villar R.
Published: October 2003

An efficient physical‐optics formulation in the time domain (TDPO), combined with the finite‐difference time‐domain method (FDTD), is presented to evaluate the near scattered field from a base‐station antenna by a surrounding obstacle. This technique is used to demonstrate compliance guidelines related to human exposure to those antennas in its operational environment. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 39: 393–395, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11227
An enhanced 2 × 2 antenna array based on a dumbbell EBG structure
Authors: Jin Nanbo , Yu Ang , Zhang Xuexia
Published: October 2003

In this paper, a novel uniplanar compact EBG structure—a dumbbell structure—is used in the design of a 2 × 2 microstrip antenna array, which has a resonant frequency of 5.6 GHz. Due to the suppression of the surface wave introduced by the EBG structure, the E‐plane mutual coupling between the array elements is reduced, as well as the side‐lobe level in the E‐plane radiation pattern. Moreover, a 1.5‐dB increase in the gain of the main lobe is observed. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 39: 395–399, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11228
RF SAW filter package design for wireless communications
Authors: Finch Craig , Yang Xiaomin , Wu Thomas X. , Abbott Benjamin
Published: October 2003

This paper describes a new method to design a ceramic chip and wire package for an RF SAW filter. Both the solid model of the package and bond wires are included in the full‐wave analysis. A novel port configuration is used in finite‐element simulation. Agreement between measurement and simulation is found to be excellent. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 39: 399–401, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11229
Nonlinear phase shifts in the design of comb‐like dispersion‐profiled fiber for pulse compression
Authors: Wang Jianping , Wu Yue , Lou Caiyun , Gao Yizhi
Published: October 2003

In the design of comb‐like dispersion‐profiled fiber (CDPF) for pulse compression, the length of the dispersion shift fiber (DSF) is determined by the nonlinear phase shift of each segment. To achieve a higher compression factor, it is necessary to increase the phase shift experienced by the pulse in each segment. However, a too large phase shift generally results in severe pulse distortion or breakup and the shedding of a large proportion of the pulse energy to a dispersive background level. Pulse‐compression experiments are made with three different CDPFs of different nonlinear phase shifts and a high‐quality compression effect is achieved. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 39: 401–404, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11230
Experimental studies of a slot‐loaded triangular folded planar inverted‐F antenna
Authors: Row Jeen‐Sheen , Ai Ching‐Yuan
Published: October 2003

This paper presents the experimental results of a single‐feed triangular folded planar inverted‐F antenna loaded with a V‐shaped slot. By placing the V‐shaped slot at different positions in an isosceles‐triangular microstrip patch, novel multiband and broadband operations of the proposed antenna can be achieved. Results show that an operating bandwidth of more than 30% is obtained when the slot is placed near the center of the triangular patch and a triple‐band operation is achieved when the slot is close to the edge of the triangular patch. Details of the proposed designs are described and typical experimental results are presented and discussed. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 39: 404–406, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11231
Design of wideband base station antenna arrays for CDMA 800 and GSM 900 systems
Authors: Hui K. Y. , Luk K. M.
Published: October 2003

Arrays of wideband L‐probe stacked patch antennas are designed for applications in both CDMA and GSM base stations with operating frequency range form 820 to 960 MHz (SWR ≤ 1.5). Different values of antenna gains are achieved with the use of four, six, and eight elements. A set of element separations and phases for each array is found for the excitation of a shaped radiation pattern with null‐filling and upper side‐lobe suppression. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 39: 406–409, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11232
RF parameter extraction of MMIC nichrome resistors
Authors: Sharma Renu , Vinayak Seema , Rawal D. S. , Kumar Ashok , Ray U. C.
Published: October 2003

The lumped‐element electrical equivalent circuit of nichrome (NiCr) resistors is important for monolithic microwave integrated circuit (MMIC) design. This paper presents a methodology for the RF parameter extraction of thin‐film NiCr resistors fabricated on GaAs substrate. An algorithm based on DUT S parameters has been developed to extract the electrical parameters of the equivalent circuit up to 18 GHz for a large number of resistors of varying geometries and geometry‐scaleable curve‐fitted equations for the model parameters have been obtained. The computed S parameters, based on the extracted model parameters, agree reasonably well with the measured S parameters. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 39: 409–412, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11233
A new PBG structure: Corrugated CPW
Authors: Kim S. J. , Myung N. H.
Published: October 2003

This paper presents a new photonic bandgap (PBG) structure with a coplanar waveguide (CPW). The use of slots on the ground prohibits the propagation of the quasi‐TEM mode along the CPW line and provides the two characteristics of stopband periodicity and slot‐depth dependency of the stopband position. We implement two PBG structures which exhibit good performance with compact size. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 39: 412–414, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11234
A 52 GHz VCO with low‐phase noise implemented in SiGe BiCMOS technology
Authors: Jia Lin , Ma Jian‐Guo , Cabuk Alper , Yeo Kiat Seng , Do Manh Anh
Published: October 2003

A fully integrated 52‐GHz millimeter‐wave LC voltage‐controlled oscillator (VCO) with −106 dBc/Hz phase noise at 600‐kHz offset frequency and 0.93‐GHz tuning range is reported in this paper using IBM BiCMOS‐6HP technology. The output voltage swing of the VCO is about 0.4 Vp‐p for the complementary cross‐coupled topology with a buffer. A bipolar device is used as the tail transistor to constantly supply a current in order to preserve the oscillation of the VCO. The parasitics due to the interconnected metals are extracted from the layout, and the effects of those parasitics on the VCO's performance are investigated. Based on these analyses, an optimized layout of the complementary VCO is obtained, and the pre‐layout and post‐layout simulations are compared and presented. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 39: 414–418, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11235
On the design of broadband omnidirectional compact antennas
Authors: Bergmann J. R.
Published: October 2003

The conventional discone antenna is well known as an easy‐to‐build broadband antenna with a vertically polarized omnidirectional radiation pattern. Here, we consider an alternative configuration where both metallic surfaces involved in discone‐type antennas are shaped. A study is performed to find body shapes that simultaneously minimize the antenna's cross‐section area and improve the antenna's performance. For this study, a numerical model based on the method of moments (MoM) is employed and the parameters used to describe the antenna shape are explored. A design example of the modified discone‐type antenna is presented and its performance is compared with that of a conventional discone antenna. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 39: 418–422, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11236
Analysis of different GA strategies applied to antenna far‐fields reconstruction from planar acquisition
Authors: Pérez J. R. , Basterrechea J.
Published: October 2003

The performance of a binary‐coded microgenetic algorithm (GA) applied to planar near‐field antenna characterization is analyzed in this paper. The method replaces the antenna with an equivalent model consisting of short dipoles, whose optimization is carried out using different GA strategies. Results of reconstructed far‐field patterns from synthetic near‐field data and a detailed analysis of the GA‐based approach are included. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 39: 422–426, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11237
Implementation of coupling improvement in coupled lines with different metallization thickness
Authors: Hong Ic‐Pyo , Park Seong‐Kyoon
Published: October 2003

In this paper, we present new types of tightly coupled lines using asymmetrical metallization thickness. A mode‐matching method has been used to analyze this new structure and the simulation results are validated through comparison with the available results. The results in this paper show that the asymmetrical metallization thickness properties of coupled lines can be newly added to the design parameters to improve the tightly coupled characteristics of microwave applications. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 39: 426–428, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11238
A double‐layer FSS structure to suppress far side‐lobes of an antenna
Authors: Shaker Jafar , Cuhaci Michel
Published: October 2003

A two‐layer frequency‐selective surface (FSS) is proposed for the suppression of far‐side lobes of radiating elements as an extension of the single‐layer FSS that is used for the suppression of near‐boresight side lobes. Based on the affinity of the proposed structure with the Fabry–Perot resonator, a method is developed for its analysis and design. The limitations of the method of analysis are discussed. A guideline is given for the design of a double‐layer FSS structure for the suppression of far‐side lobes of a radiating structure. A double‐layer filter is designed, fabricated, and used in conjunction with several radiating elements which achieve suppressed side lobes in the angular range of 40°–50° by 15 dB. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 39: 428–432, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11239
Seasonal changes in avian song control circuits do not cause seasonal changes in song discrimination in song sparrows
Authors: Reeves Brendan J. , Beecher Michael D. , Brenowitz Eliot A.
Published: October 2003

In seasonally breeding songbirds, brain nuclei of the song control system that act in song perception change in size between seasons. It has been hypothesized that seasonal regression of song nuclei may impair song discrimination. We tested this hypothesis in song sparrows (Melospiza melodia), a species in which males share song types with neighbors and must discriminate between similar songs in territorial interactions. We predicted that song sparrows with regressed song systems would have greater difficulty in discriminating between similar songs. Sparrows were housed either on short days (SD) and had regressed song circuits, or were exposed to long days and implanted with testosterone (LD+T) to induce full growth of the song circuits. We conducted two experiments using a GO/NO‐GO operant conditioning paradigm to measure song discrimination ability of each group. Birds learned four (experiment 1) or three (experiment 2) pairs of song types sequentially, with each pair more similar in the number of shared song elements and thus more difficult to discriminate. Circulating T levels differed between the SD and LD+T groups. The telencephalic song nuclei HVc, RA, and area X were larger in the LD+T birds. The two groups of sparrows did not differ, however, in their ability to learn to discriminate between shared song types, regardless of the songs' similarity. These results suggest that seasonal changes in the song control system do not affect birds' ability to make difficult song discriminations. © 2003 Wiley Periodicals, Inc. J Neurobiol 57: 119–129, 2003
Methylene blue blocks cGMP production and disrupts directed migration of microglia to nerve lesions in the leech CNS
Authors: Duan Yuanli , Haugabook Sharie J. , Sahley Christie L. , Muller Kenneth J.
Published: October 2003

Migration and accumulation of microglial cells at sites of injury are important for nerve repair. Recent studies on the leech central nervous system (CNS), in which synapse regeneration is successful, have shown that nitric oxide (NO) generated immediately after injury by endothelial nitric oxide synthase (eNOS) stops migrating microglia at the lesion. The present study obtained results indicating that NO may act earlier, on microglia migration, and aimed to determine mechanisms underlying NO's effects. Injury induced cGMP immunoreactivity at the lesion in a pattern similar to that of eNOS activity, immunoreactivity, and microglial cell accumulation, which were all focused there. The soluble guanylate cyclase (sGC) inhibitor methylene blue (MB) at 60 μM abolished cGMP immunoreactivity at lesions and blocked microglial cell migration and accumulation without interfering with axon conduction. Time‐lapse video microscopy of microglia in living nerve cords showed MB did not reduce cell movement but reduced directed movement, with significantly more cells moving away from the lesion or reversing direction and fewer cells moving toward the lesion. The results indicate a new role for NO, directing the microglial cell migration as well as stopping it, and show that NO's action may be mediated by cGMP. © 2003 Wiley Periodicals, Inc. J Neurobiol 57: 183–192, 2003
Androgens and estrogens induce seasonal‐like growth of song nuclei in the adult songbird brain
Authors: Tramontin Anthony D. , Wingfield John C. , Brenowitz Eliot A.
Published: October 2003

In seasonally breeding songbirds, the brain regions that control song behavior undergo dramatic structural changes at the onset of each annual breeding season. As spring approaches and days get longer, gonadal testosterone (T) secretion increases and triggers the growth of several song control nuclei. T can be converted to androgenic and estrogenic metabolites by enzymes expressed in the brain. This opens the possibility that the effects of T may be mediated via the androgen receptor, the estrogen receptor, or both. To test this hypothesis, we examined the effects of two bioactive T metabolites on song nucleus growth and song behavior in adult male white‐crowned sparrows. Castrated sparrows with regressed song control nuclei were implanted with silastic capsules containing either crystalline T, 5α‐dihydrotestosterone (DHT), estradiol (E2), or a combination of DHT+E2. Control animals received empty implants. Song production was highly variable within treatment groups. Only one of seven birds treated with E2 alone was observed singing, whereas a majority of birds with T or DHT sang. After 37 days of exposure to sex steroids, we measured the volumes of the forebrain song nucleus HVc, the robust nucleus of the archistriatum (RA), and a basal ganglia homolog (area X). All three steroid treatments increased the volumes of these three song nuclei when compared to blank‐implanted controls. These data demonstrate that androgen and estrogen receptor binding are sufficient to trigger seasonal song nucleus growth. These data also suggest that T's effects on seasonal song nucleus growth may depend, in part, upon enzymatic conversion of T to bioactive metabolites. © 2003 Wiley Periodicals, Inc. J Neurobiol 57:130–140, 2003
Neuromuscular activity impairs axonal sprouting in partially denervated muscles by inhibiting bridge formation of perisynaptic Schwann cells
Authors: Tam S. L. , Gordon T.
Published: October 2003

Following partial denervation of rat hindlimb muscle, terminal Schwann cells extend processes from denervated endplates to induce and guide sprouting from the remaining intact axons. Increased neuromuscular activity significantly reduces motor unit enlargement and sprouting during the acute phase of sprouting. These findings led to the hypothesis that increased neuromuscular activity perturbs formation of Schwann cell bridges and thereby reduces sprouting. Adult rat tibialis anterior (TA) muscles were extensively denervated by avulsion of L4 spinal root and were immediately subjected to normal caged activity or running exercise (8 h daily) for 3, 7, 14, 21, and 28 days. Combined silver/cholinesterase histochemical staining revealed that the progressive reinnervation of denervated endplates by sprouts over a 1 month period in the extensively partially denervated TA muscles was completely abolished by increased neuromuscular activity. Immunohistochemical staining and triple immunofluorescence revealed that the increased neuromuscular activity did not perturb the production of Schwann cell processes, but prevented bridging between Schwann cell processes at innervated and denervated endplates. Our findings suggest that failure of Schwann cell processes to bridge between endplates accounts, at least in part, for the inhibitory effect of increased neuromuscular activity on sprouting. © 2003 Wiley Periodicals, Inc. J Neurobiol 57: 221–234, 2003
Changes in trabecular bone structure in rickets and osteomalacia: the potential of a medico‐historical collection
Authors: Schamall D. , Teschler‐Nicola M. , Kainberger F. , Tangl St. , Brandstätter F. , Patzak B. , Muhsil J. , Plenk H.
Published: October 2003

In this study lumbar vertebral bodies with and without disturbed mineralization from a medico‐historical collection of the 19th century (housed in the Federal Museum for Pathological Anatomy, Vienna) were investigated, using non‐invasive radiological and invasive histological techniques. Macerated, or partly dissected, or fixation fluid conservated skeletal preparations from 61 individuals with known age and gender were examined. The specimens of 37 individuals had gross pathologic alterations from rickets or osteomalacia. The specimens from 24 individuals without Known bone disease served as age‐matched controls. Bone structure and mineralization in all specimens were evaluated by non‐invasive techniques (conventional radiographs and computed tomography). Thirteen selected specimens from both groups were also analysed by quantitative computed tomography (qCT) and dual‐energy X‐ray absorptiometry (DEXA). In these cases invasive techniques (light and scanning electron microscopy [backscattered electron (BSE)‐ and secondary electron (SE)‐mode] on surface‐stained and carbon‐sputtered undecalcified histological ground sections) were applied. Corresponding microradiographs were also used for computer‐assisted morphometry. The clinically established method of determination of bone mineral densities (BMD) by qCT and DEXA failed in these historical specimens, but all other non‐invasive and invasive techniques were successfully applied and yielded results corresponding to radiological changes and histomorphometric parameters. In the rachitic vertebrae it was not volume densities (bone volume per tissue volume = BV/TV), but numbers of trabeculae (trabecular number = Tb.N.) which were increased, compared to the age‐matched vertebral bodies without bone disease. In osteomalacic vertebrae the volume densities (BV/TV) were decreased in the whole vertebral body, while Tb.N. were only decreased in the middle third of the vertebral body. Accordingly, surface densities (SV) in non‐adults, and also specific surfaces (S/V) in adults were increased, suggesting increased bone resorption. Depending on the preparation technique used in the present study, resorption lacunae and characteristic unmineralized osteoid seams could be demonstrated. In conclusion, it might be useful to establish such techniques and standards for the diagnosis of disturbed mineralization in clinical patients. Copyright © 2003 John Wiley & Sons, Ltd.
Shape sensitivities in a Navier‐Stokes flow with convective and grey bodies radiative thermal transfer
Authors: Monnier J.
Published: October 2003

We study a shape optimal design problem for a forced convection flow: the steady‐state Navier–Stokes equations coupled with an integro‐differential thermal model. The thermal transfers are convective, diffusive and radiative with multiple reflections (model of grey bodies, radiosity equation). The inverse problem consists in minimizing a smooth cost function which depends on the solution, with respect to the domain of the equations. We prove the differentiability of the solution with respect to the domain. It follows the cost function differentiability. We introduce the adjoint state equation and obtain the exact differential of the cost function. The computational method of shape sensitivities and the optimization process are presented too. Copyright © 2003 John Wiley & Sons, Ltd.
Using logarithmic penalties in the shooting algorithm for optimal control problems
Authors: Bonnans J. F. , Guilbaud Th.
Published: October 2003

The paper deals with optimal control problems of ordinary differential equations with bound control constraints. We analyse the logarithmic penalty method for converting the problem into an unconstrained one, the latter being solved by a shooting algorithm. Convergence of the value function and optimal controls is obtained for linear quadratic problems, and more generally when the control variable enters linearly in the state equation and in a quadratic way in the cost function. We display some numerical results on two examples: an aircraft maneuver, and the stabilization of an oscillating system. Copyright © 2003 John Wiley & Sons, Ltd.
Solving multi‐objective dynamic optimization problems with fuzzy satisfying method
Authors: Chen Cheng‐Liang , Chang Chia‐Yuan , Sun Daim‐Yuang
Published: October 2003

This article proposes a novel algorithm integrating iterative dynamic programming and fuzzy aggregation to solve multi‐objective optimal control problems. First, the optimal control policies involving these objectives are sequentially determined. A payoff table is then established by applying each optimal policy in series to evaluate these multiple objectives. Considering the imprecise nature of decision‐maker's judgment, these multiple objectives are viewed as fuzzy variables. Simple monotonic increasing or decreasing membership functions are then defined for degrees of satisfaction for these linguistic objective functions. The optimal control policy is finally searched by maximizing the aggregated fuzzy decision values. The proposed method is rather easy to implement. Two chemical processes, Nylon 6 batch polymerization and Penicillin G fed‐batch fermentation, are used to demonstrate that the method has a significant potential to solve real industrial problems. Copyright © 2003 John Wiley & Sons, Ltd.
Ab initio CI calculations of the potential curves and nonadiabatic coupling matrix elements for collisions of protons with the ethylene molecule
Authors: Rai Sachchida N. , Liebermann Heinz‐Peter , Buenker Robert J. , Kimura Mineo
Published: October 2003

The interaction of ethylene with a single proton has been studied theoretically by means of multireference configuration interaction calculations. Potential energy surfaces have been obtained as well as both radial and rotational nonadiabatic coupling matrix elements. Three different approaches of the proton toward the midpoint of the target molecule have been considered for eight collision channels. Along the π direction a number of deep potential minima have been found and the ground‐state proton affinity is calculated to be 7.25 eV on this basis. There is a strongly avoided crossing in this case between the higher‐energy C2H4/H+ incoming channel and the ground C2H/H singlet state, and the corresponding radial coupling matrix element has a broad shape as a result. For the approaches along the in‐plane perpendicular axes of the molecule there is a potential crossing for these two states due to their different symmetries in these orientations, from which it is clear that the incoming channel is strongly bound whereas the charge‐transfer state is repulsive. Comparison with available experimental results indicates that the computed energy differences between the electronic states are accurate to within 0.1–0.2 eV. For the approach along the CC bond there is a weakly avoided crossing between the lowest triplet state of C2H4 and the C2H state corresponding to ionization from the σ molecular orbital (MO). One of the potential minima occurring for the π approach is seen to result from a doubly excited state in which the two π electrons are transferred to a π* MO and the incoming proton, respectively, so that a relatively stable three‐center bond is formed. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem, 2003
The strain energy of perchlorocyclopropane is small: It might even be negative. A density functional theory study of perhalocycloalkanes
Authors: Mahavadi Madhavi , Zeiger Diana N. , Naqib Dahlia , Roux Maria Victoria , Notario Rafael , Liebman Joel F.
Published: October 2003

The strain energy for the parent, perfluoro‐, and perchlorocycloalkanes (CnX2n, X = H, F, and Cl, n = 3–6) is evaluated using a variety of equations (homodesmotic, group increment, and diagonal) and density functional theory calculations [B3P86/6‐311+G(2df,p)//6‐311G(d)]. Literature trends are reproduced for the fluorinated species. Results, although explained, for chlorinated compounds are still a source of surprise: The strain energy of perchlorocyclopropane is small and may well be negative. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem, 2003
Molecular quadrupole moments of HCCH, FCCF, and ClCCCl
Authors: Gearhart Dorothy J. , Harrison James F. , Hunt Katharine L. C.
Published: October 2003

The molecular quadrupole moments of HCCH, FCCF, and ClCCCl have been studied as a function of basis set at the self‐consistent field, density functional theory (B3LYP), and CCSD(T) levels. The CCSD(T) results, in units of ea, are 4.856 (HCCH), −0.6389 (FCCF), and 3.7685 (ClCCCl). When corrected for vibration, the HCCH result is reduced to 4.795 and is in excellent agreement with experiment, 4.71 ± 0.14. There are no experimental data for FCCF and ClCCCl. The molecular quadrupole moments are shown to have the form Θ = Θatoms + Θcr, where Θatoms is the sum of the quadrupole moments of the separated atoms and Θcr is the contribution due to charge redistribution upon molecule formation. This model accounts for the magnitude and signs of Θ in this series. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem, 2003