bluuebunny/crossref_metadata_2025 huggingface dataset:
Multiple‐grating microwave volume holograms based on printed artificial dielectrics: Analysis and measurement
Authors: Zhu Wenhao , McNamara Derek A. , Shaker Jafar
Published: August 2006

A multiple‐grating artificial microwave volume hologram (AMVH) is presented, which is designed based on the idea of multiply‐exposed optical holograms and is realized using printed artificial dielectric technique. It consists of a 3D conducting disk array formed by cascading a finite number of planar disk lattices and has its disk size varying in both the transverse (x) and normal (z) directions to simulate an effective 2‐D holographic grating. The reconstructed beams from such a multiplex AMVH are analyzed and a low cross‐talk between gratings is obtained. Comparison with the measured results on the fabricated multiplex AMVH prototype has confirmed the design and simulation. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 2179–2184, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21886
A subharmonically injected phase‐locked loop for 5‐GHz applications
Authors: Plessas Fotis , Kalivas Grigorios
Published: August 2006

This work introduces a modified subharmonic injection‐locked phase‐locked loop (S‐ILPLL) that feeds the phase comparator with half the frequency of the voltage‐controlled oscillator by employing a divider in the loop feedback path. The main objective is to address the phase noise improvement of subharmonic ILPLLs, especially for the 5‐GHz band. Theoretical analysis and computer calculations demonstrate an improved performance for phase noise and power consumption. An experimental prototype was implemented to verify the validity of the proposed approach. Measurement results are in good agreement with computer calculations, thus the proposed S‐ILPLL can constitute an attractive design approach for 5‐GHz WLAN synthesizers. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 2158–2162, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21888
FHSS optical wireless transceiver for short range low‐speed indoor sensor interconnection
Authors: Delgado F. , Jiménez R. Pérez , Pérez S. , González O.
Published: August 2006

Experimental and simulation results from the operation of a prototype of wireless indoor optical transceiver based on frequency hopping techniques are presented. We choose spread spectrum techniques, as it allows multiple simultaneous accesses and also increases the robustness of the system against multipath‐induced distortion. It also reduces the effect of narrowband interference, as could be low‐frequency optical noise from fluorescence or incandescence lamps. FHSS techniques also allow coexistence with IrDA or remote control emitting devices without causing of suffering interferences. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 2193–2197, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21889
Investigation on probe‐fed open‐ring microstrip antenna for miniaturization
Authors: Latif Saeed I. , Shafai Lotfollah
Published: August 2006

Gap‐loaded microstrip square‐ring antennas are investigated in this study. Because of the gap loading, the square‐ring antenna resonates at much lower frequency than that in the unloaded case, which gives a miniaturized narrowband antenna. A detail parametric study is carried out to understand its properties. An experimental prototype is fabricated and its performance is compared with simulations, confirming the computed results. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 2175–2179, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21890
TLM modelling of microwave applicator with an excitation through the waveguide
Authors: Joković Jugoslav , Milovanović Bratislav , Ranđelović Tijana
Published: August 2006

A microwave applicator with a waveguide used to launch the energy from the source into the metallic cavity is modelled using 3D‐TLM method. An influence of waveguide position to the resonant modes distribution inside both empty and loaded cavities is analyzed, comparing numerical results with analytical and experimental ones. © Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 2320–2326, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21895
High temperature pulsed measurements of AlGaN/GaN HEMTs on high resistive Si(111) substrate
Authors: Werquin M. , Ducatteau D. , Vellas N. , Delos E. , Cordier Y. , Aubry R. , Gaquière C.
Published: August 2006

DC‐ and RF‐pulsed measurements of AlGaN/GaN HEMTs on high resistive silicon (111) substrate are achieved under probes in the 300–525 K temperature range. Current collapse and heating effects are studied and it demonstrates the high temperature properties of these devices. Hence the potential of this technology for power applications at microwave frequencies is confirmed. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 2301–2305, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21897
Design and fabrication of integrated film bulk acoustic resonator and filter on silicon nitride membrane
Authors: Park Jae Yoeng , Lee Hee Chul , Cheon Seong Jong
Published: August 2006

In this paper, fully integrated film bulk acoustic resonators (FBARs) and filter have been designed, fabricated, and characterized by using silicon bulk micromachining technology. The fabricated resonator is comprised of aluminum nitride (AlN) piezoelectric material sandwiched by two molybdenum (Mo) electrodes on top of silicon nitride thin membrane. The developed AlN piezoelectric film has 1.9° of FWHM (full width half maximum) of rocking curve and approximately 70 Mpa in tensile stress on top of the Mo electrode. The fabricated FBAR has a quality factor of 1530 in size of 200 × 200 μm2, insertion loss of −0.45 dB, and return loss of −28 dB, respectively. The fabricated FBAR ladder type filter is comprised of 7 resonators with 3 resonators in series and 4 resonators in parallel. It has insertion loss of −3.2 dB and ripple of 0.4 dB in pass band, absolute attenuation of 40 and 50 dB at 1.6–1.875 GHz and 2.110–2.170 GHz, respectively. The size of the fabricated FBAR filter is 1.2 mm × 1.4 mm before packaging and 3 mm × 3 mm after packaging, respectively. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 2230–2233, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21905
Broadband and high‐gain microstrip slot antenna
Authors: Yao Feng‐Wei , Zhong Shun‐Shi
Published: August 2006

A novel microstrip slot antenna backed by a ground plane of large bandwidth and high gain is presented. A fan‐shaped termination of a microstrip feeder with a straight stub is used to excite a rectangular slot and a circular patch to realize the broadband characteristic. Its measured voltage standing wave ratio (VSWR) ≤2 bandwidth reaches ∼102%, covering 1.97–6.05 GHz with the ratio bandwidth of 3.07:1. The measured antenna gain is 5.5–7.8 dB over the entire bandwidth. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 2210–2212, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21907
Electronically controlled reciprocal phase shifter
Authors: Collin G. , Ditchi T. , Géron E. , Holé S.
Published: August 2006

A reciprocal phase shifter principle is proposed, of very simple design with only one control voltage, which enables the continuous variation of the phase at a frequency of 1.89 GHz. An implementation on Teflon substrate using Wilkinson dividers and a second‐order filter using one variable capacitor is presented. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 2301–2303, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21911
Coplanar waveguide‐fed band‐selective filter for wideband antenna
Authors: Wang Chien‐Jen , Wu Jin‐Wei
Published: August 2006

In this study, a coplanar waveguide‐fed band‐selective filter and a spiral slot antenna have been designed, fabricated, and integrated for the applications of multisystem integration. The antenna module was fabricated on the same plane of the substrate, so that the circuit process and the position alignment could be simplified. The passband responses of the filter ranging below 2.6 GHz and from 5.0 to 6.0 GHz cover most of the commercial wireless communication systems. Simulated results are compared with measurements performed on the antenna module. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 2264–2267, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21915
A dual degenerate mode X‐band bandpass filter in LTCC
Authors: Tan Boon Tiong , Chew Siou Teck , Leong Mook Seng , Ooi Ban Leong
Published: August 2006

A wideband dual mode bandpass filter at 9.0 GHz with a bandwidth of 20% has been demonstrated in low temperature cofired ceramics (LTCC). A new stacked‐ring resonator (SRR) is proposed and its design methodology as well as analysis is presented in details. The simulated and measured results are in good agreement. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 2246–2249, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21917
Harmonic suppression in parallel coupled microstrip bandpass filter with embedded C‐shaped EBG cells
Authors: Wu Hung‐Wei , Chang Sheng‐Hsiung , Weng Min‐Hang , Kuan Hon , Su Yan‐Kuin
Published: August 2006

In this article, harmonic suppression of a parallel coupled microstrip bandpass filter (BPF) with C‐shaped electromagnetic bandgap (EBG) cells embedded on the middle layer is investigated. The embedded C‐shaped EBG cells patterned on the middle layer add a good stopband‐rejection mode to the second harmonics of the parallel coupled microstrip BPF with suppression of over −40 dB, without affecting the center frequency and insertion loss of the original designed BPF. The experimented results matched the simulated results well. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 2244–2246, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21918
Backlobe reduction for vertical patch antenna
Authors: Lau Ka‐Lam , Wong Ting‐Pong , Luk Kwai‐Man , Lee Kai‐Fong
Published: August 2006

ABSTRACT: This paper presents a modified ground plane design for a circular vertical patch antenna (VPA). The circular‐VPA is surrounded by a circular corrugated ground and it has around 10% impedance bandwidth and 8 dBi gain. This design yields a significant reduction in cross‐polarization radiation and back radiation levels over a bandwidth in excess of 9.5%. A 15 dB reduction in the cross‐polarization and 15 dB suppression in the backlobe were obtained at the center frequency. Stable and broadside patterns are maintained across the matching band. Details of the proposed antenna, simulation and experimental results are presented and discussed. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 2297–2299, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21925
Experimental verification of the relation between the radar cross section and the list angle of surface vessels
Authors: Ojeda J. F. Pérez , Rodríguez J. L. , García‐Tuñón I. , Obelleiro F.
Published: August 2006

In this paper, the effect of ship angular motions on the radar cross section is addressed. To this end, a set of measurements for different ships were conducted from a shore‐based instrumental radar. The targets execute oblique straight trajectories with respect to the radar line of sight with induced roll. The analysis of the dependence between target reflectivity and the roll angle shows that, for conventional vessels, the maximum response at low grazing angles is achieved in steady conditions, and it varies significantly according to the sign of the roll angle referred to the radar location. This result is confirmed by the comparison of measurements of a ship performing turning circles at several speeds, thus inducing different roll angles. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 2237–2241, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21932
Using tap basis to implement the equivalence principle algorithm for domain decomposition in integral equations
Authors: Li Mao‐Kun , Chew Weng Cho
Published: August 2006

A domain decomposition scheme based on the equivalence principle, also known as Huygens' principle, for integral equation solvers and the method of moments is introduced here. The equivalence principle allows the replacement of unknown currents distributed in a volume in space by equivalent currents residing on the surface that bounds the volume. In this manner, a problem of high complexity can be replaced by a surface of simpler shape. A tap basis is introduced to model the current that intercepts with the equivalence surfaces. Using this scheme, the current continuity is conserved and the singularity of the charges is avoided. The solution is shown to be accurate. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 2218–2222, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21933
Single‐feed elliptical dielectric resonator antennas for circularly polarized applications
Authors: Yang S. L. Steven , Chair Ricky , Kishk A. A. , Lee K. F. , Luk K. M.
Published: August 2006

A single‐feed elliptical shape dielectric resonator antenna (DRA) is designed for circular polarization application. The antenna is simple in structure and could be excited by either a probe or a narrow aperture. This antenna excites two degenerate orthogonal modes with 90° phase difference. From experimental studies, the single probe feed DRA achieves 5.2% 3‐dB axial ratio (AR) bandwidth and 17.3% impedance matching bandwidth (S11 < −10 dB), and the single aperture feed DRA achieves 4.2% AR bandwidth and 26.5% impedance matching bandwidth. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48:2340–2345, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21937
Ultrabroad tunable wavelength conversion in a semiconductor optical amplifier
Authors: Lu Z. G. , Bock P. , Liu J.R. , Florjanczyk M. , Hall T.
Published: August 2006

By using two orthogonally‐polarized pump beams, an over 10.66 THz tuning range wavelength converter is demonstrated with uniform conversion efficiency and equalized signal‐to‐noise ratio (SNR) through four‐wave mixing in semiconductor optical amplifier. The pumping‐beam effects on both conversion efficiency and SNR of the converted signals are investigated. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 2139–2142, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21938
Circularly polarized broadband high‐efficiency active integrated antenna
Authors: Gao S. , Qin Y. , Sambell A.
Published: August 2006

This letter presents a circularly polarized (CP) broadband high‐efficiency active integrated antenna, where the broadband CP antenna is integrated directly with a broadband high‐efficiency class‐E power amplifier (PA). To achieve CP operation, a series feed using an L‐shaped microstrip feed line below the ground plane is used to provide a 90° phase shift between crossed slots. The antenna serves both functions of a broadband CP radiator and a broadband harmonics‐termination load network for the class‐E PA. Measures results demonstrate both broadband CP radiation and high efficiency. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 2145–2148, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21940
Dual‐band internal WLAN antenna for 2.4/5 GHz laptop PC applications
Authors: Cho Young Jun , Shin Yong Sun , Park Seong‐Ook
Published: August 2006

This paper presents a dual‐band internal WLAN PIFA for 2.4/5 GHz laptop applications in consideration of the influences of laptop housing and LCD. The prototype antenna is modified when installed along the perimeter of the display panel of the laptop housing. The proposed antenna has a small ground plane and achieves an impedance bandwidth of 250 MHz (2.37–2.62 GHz(in Bluetooth band and 950 MHz (4.98–5.93 GHz(near 5 GHz in WLAN band within 2:1 voltage standing wave ratio (VSWR(. It also shows good antenna gain with small volume. These features make it an alternative for use in dual‐band WLAN antennas. Design details for the proposed antenna in the case of the antenna itself, and the application of laptop PC housing are described, and experimental results of the antenna achievements are investigated and discussed. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48:2349–2354, 2006;Published online in Wiley InterScience (www.interscience.wiley.com).DOI 10.1002/mop.21943
High‐power emission, narrow‐beam scanning, and sub‐wavelength imaging using conducting gratings and left‐handed materials
Authors: Li Zhuo , Cui Tie Jun , Zhang Jian Feng
Published: August 2006

Many amazing properties of a novel electromagnetic (EM) structure, consisting a conducting grating backed with a left‐handed material (LHM) slab, are studied. High‐directivity, high‐power emission and narrow‐beam scanning can be easily realized when this structure acts as an antenna. Simultaneously, if it works as an imaging system, extremely high resolution can also be obtained with the unique EM behaviors of the LHM. Proper usage of surface waves on apertures opened in the conducting screen makes this structure possess such attractive capabilities. In order to investigate such phenomena, a more general EM model is first developed through the equivalence principle, and then the method of moments is implemented to obtain the interesting results. All these amazing properties are clearly observed through the numerical results. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48:2359–2365, 2006;Published online in Wiley InterScience (www.interscience.wiley.com).DOI 10.1002/mop.21944
Tunable polarization optical delay line based on a linear chirped fiber Bragg grating
Authors: Nogueira Rogério N. , da Rocha José R. F. , Pinto João L.
Published: August 2006

A new technique for inducing relative group delays between the orthogonal transversal propagation modes in a single mode fiber is presented. It is based on a tunable linear chirp induced in a Bragg grating written in a highly birefringent fiber by thermal means. The method can induce a relative delay over a wide range, making it possible for use in a polarization mode dispersion compensator. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48:2357–2359, 2006; Published online in Wiley InterScience (www.interscience.wiley.com).DOI 10.1002/mop.21945
Orthogonal projection sampling method used in reconstruction of incomplete data field
Authors: Hongbing Yao , Xia Ye , Jun Zhou , Anzhi He
Published: August 2006

An orthogonal projection sampling method is proposed in this paper for the reconstruction of incomplete data field by using the prior knowledge algorithm based on the modified algebra reconstruction technology (ART) in the optical computerized tomography (OCT). Experiments based to this method are studied. The satisfying reconstruction results are obtained with less sampling projection numbers and limited sampling angular range. The results indicate that orthogonal projection sampling can improve the precision in the reconstruction of incomplete data, and the precision reaches 10%. © 2006 Wiley Periodicals,Inc. Microwave Opt Technol Lett 48:2333–2336, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21947
A compact microstrip bandpass filter using folded parallel‐coupled‐lines
Authors: Gu Jian‐Zhong , Sun Xiao‐Wei
Published: August 2006

A bandpass filter using spiral parallel‐coupled‐lines is presented for size reduction. Based on the conventional parallel‐coupled‐line structures, different folded number and coupling structures are proposed for comparison. The band‐pass filter with three cells in series is constructed operating from 1.8 GHz to 2.5 GHz. The upper stop‐band suppression at 200 MHz offset is more than 30 dB. The band‐pass filter size is 70% smaller. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 2328–2330, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21949
Protolytic properties of polyamine wasp toxin analogues studied by13C NMR spectroscopy
Authors: Strømgaard Kristian , Piazzi Lorna , Olsen Christian A. , Franzyk Henrik , Jaroszewski Jerzy W.
Published: August 2006

Acid–base properties of the natural polyamine wasp toxin PhTX‐433 (1) and seven synthetic analogues [PhTX‐343 (2), PhTX‐334 (3), PhTX‐443 (4), PhTX‐434 (5), PhTX‐344 (6), PhTX‐444 (7), and PhTX‐333 (8)], each having four protolytic sites, were characterized by13C NMR spectroscopy. Nonlinear, multiparameter, simultaneous fit of all chemical shift data obtained from the NMR titration curves yielded macroscopic pKavalues as well as intrinsic chemical shift data of all differently protonated macrospecies. Analyses of the chemical shift data demonstrated strong interactions between all four sites and provided information about complex relationships between chemical shift values and protonation state. Deprotonation of fully protonated forms starts at the central amino group of the polyamine moiety, and the extent of this trend depends on the distance to the flanking, protonated amino groups. The pKa1values of 1–8 are in the range 8.2–9.4. Hence, some of the toxins are incompletely protonated at the pH and ionic strength conditions used for assessment of their interactions with ionotropic glutamate and nicotinic acetylcholine receptors, and the degree of protonation is expected to have pharmacological importance in the ion‐channel binding event. Copyright © 2006 John Wiley & Sons, Ltd.
Differentiation of female primordial germ cells in the male testes of chicken (Gallus gallus domesticus)
Authors: Tagami Takahiro , Kagami Hiroshi , Matsubara Yuko , Harumi Takashi , Naito Mitsuru , Takeda Kumiko , Hanada Hirofumi , Nirasawa Keijiro
Published: August 2006

In our previous studies, we demonstrated that female primordial germ cells (PGCs) have the ability to differentiate into W chromosome‐bearing (W‐bearing) spermatozoa in male gonads of germline chimeric chickens. In this study, to investigate the differentiation pattern of female PGCs in male gonads in chickens, three germline chimeric chickens were generated by injecting female PGCs into the male recipient embryos. After these male chimeras reached sexual maturity, the semen samples were analyzed for detecting W‐bearing cells by PCR and in situ hybridization analyses. The results indicated that the female PGCs had settled and differentiated in their testes. A histological analysis of the seminiferous tubule in those chimeras demonstrated that the W‐bearing spermatogonia, spermatocytes, and round spermatids accounted for 30.8%, 32.7%, and 28.4%, respectively. However, the W‐bearing elongating spermatid was markedly lower (7.7%) as compared to the W‐bearing round spermatid. The W‐bearing spermatozoa were hardly ever observed (0.2%). We concluded that although female PGCs in male gonads are capable of passing through the first and second meiotic division in adapting themselves to a male environment, they are hardly complete spermiogenesis. Mol. Reprod. Dev. 74: 68–75, 2007. © 2006 Wiley‐Liss, Inc.
Involvement of GnRH neuron in the spermatogonial proliferation of the scallop, Patinopecten yessoensiss
Authors: Nakamura Satoshi , Osada Makoto , Kijima Akihiro
Published: August 2006

The aim of this study was to quantitatively analyze a pattern of proliferation of gonial cells and to demonstrate neural involvement in spermatogonial proliferation of the scallop by the in vitro experiment. Immunocytochemistry for incorporated BrdU was used to identify mitotically active gonial cells. The pattern of proliferation of gonial cells was divided into two phases: phase I; oogonia and spermatogonia slowly proliferate through the growing stage: phase II; oogonia develop into oocytes and spermatogonia start to proliferate rapidly from the mature stage through the spawning stage. The neurons detected with anti‐mammalian (m)GnRH antibody were distributed sparsely in the pedal ganglion and predominantly in the cerebral ganglion of both sexes at the growing stage. The extracts from the cerebral and pedal ganglion (CPG) of both sexes collected at the growing stage promoted proliferation of spermatogonia in the in vitro culture of the testicular tissue as well as mGnRH. However, CPG extract had no effect on oogonial proliferation. The increased mitotic activity induced by CPG and mGnRH was abolished by the addition of mGnRH antagonists and anti‐mGnRH antibody, suggesting that the spermatogonial proliferation is regulated by GnRH‐like peptide in CPG of the scallop. The same mitotic activity as CPG extract and mGnRH was observed in the hemocyte lysate, but not in the serum. These findings suggest that the spermatogonial proliferation at phase II in the scallop may be under the neuroendocrine control by GnRH neuron in CPG. Mol. Reprod. Dev. 74: 108–115, 2007. © 2006 Wiley‐Liss, Inc.
Optimization of a microarray based approach for deriving representative gene expression profiles from human oocytes
Authors: Jones Gayle M. , Song Bi , Cram David S. , Trounson Alan O.
Published: August 2006

The purpose of the present study was to optimize a protocol for deriving reproducible and representative gene expression profiles from very rare research samples of human oocytes using microarrays. Immature oocytes produced as a result of administration of gonadotrophins for the treatment of infertility were donated to research. Linear amplification (L‐amp) and exponential amplification (E‐amp) were both capable of generating sufficient product for hybridization to the microarrays even from the low amount of template mRNA present in a single human oocyte. Slightly higher numbers of transcripts were detected by microarray following linear rather than E‐amp but both techniques generated a product with reliably reproducible sensitivity and fidelity providing oocytes were pooled in minimum numbers of three. The majority of the variance associated with amplification and hybridization to arrays comes from the molecular processing. Slightly greater additional variance is associated with biological differences in immature oocytes from the same or different donors. The findings suggest that representative gene expression profiles can be generated from human oocytes for comparative purposes following L‐amp and hybridization to microarray. However, oocytes must be pooled for the starting template for each array and sufficient independent microarray experiments performed to minimize the variance associated with molecular processing. Mol. Reprod. Dev. 74: 8–17, 2007. © 2006 Wiley‐Liss, Inc.
Improving MRI differentiation of gray and white matter in epileptogenic lesions based on nonlinear feedback
Authors: Huang Susie Y. , Wolahan Stephanie M. , Mathern Gary W. , Chute Dennis J. , Akhtari Massoud , Nguyen Snow T. , Huynh My N. , Salamon Noriko , Lin Yung‐Ya
Published: August 2006

A new method for enhancing MRI contrast between gray matter (GM) and white matter (WM) in epilepsy surgery patients with symptomatic lesions is presented. This method uses the radiation damping feedback interaction in high‐field MRI to amplify contrast due to small differences in resonance frequency in GM and WM corresponding to variations in tissue susceptibility. High‐resolution radiation damping‐enhanced (RD) images of in vitro brain tissue from five patients were acquired at 14 T and compared with corresponding conventional T1‐, T‐, and proton density (PD)‐weighted images. The RD images yielded a six times better contrast‐to‐noise ratio (CNR = 44.8) on average than the best optimized T1‐weighted (CNR = 7.92), T‐weighted (CNR = 4.20), and PD‐weighted images (CNR = 2.52). Regional analysis of the signal as a function of evolution time and initial pulse flip angle, and comparison with numerical simulations confirmed that radiation damping was responsible for the observed signal growth. The time evolution of the signal in different tissue regions was also used to identify subtle changes in tissue composition that were not revealed in conventional MR images. RD contrast is compared with conventional MR methods for separating different tissue types, and its value and limitations are discussed. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
Fast metabolic imaging of systems with sparse spectra: Application for hyperpolarized 13C imaging
Authors: Mayer Dirk , Levin Yakir S. , Hurd Ralph E. , Glover Gary H. , Spielman Daniel M.
Published: August 2006

A fast spiral chemical shift imaging (spCSI) sequence was developed for application to hyperpolarized 13C imaging. The sequence exploits sparse spectra, which can occur in such applications, and prior knowledge of resonance frequencies to reduce the measurement time by undersampling the data in the spectral domain. As a consequence, multiple reconstructions of a given data set have to be computed in which only components with frequencies within a certain bandwidth are reconstructed “in focus” while others are severely blurred (“spectral tomosynthesis”). The sequence was tested at 3 T on a phantom containing approximately 1.5‐M solutions of alanine (Ala), lactate (Lac), and pyruvate‐pyruvate hydrate C1‐C2 ester (with two resonances, PPE1 and PPE2) at thermal equilibrium polarization, all enriched to 99% 13C in the C1 carbonyl positions. Results from spCSI with a single spatial interleaf (single‐shot spCSI) and three interleaves (three‐shot spCSI) were compared with those obtained by phase‐encoded free induction decay CSI (FIDCSI). The metabolic maps of all four resonances for three‐shot spCSI, and of PPE1 and PPE2 for single‐shot spCSI demonstrate resolution and localization properties similar to those of the FIDCSI images. The metabolic maps of Ala and Lac for single‐shot spCSI contain minor artifacts due to signal overlap of aliased resonances. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
Transient caloric restriction in early adulthood hastens disease endpoint in male, but not female, Cu/Zn‐SOD mutant G93A mice
Authors: Hamadeh Mazen J. , Tarnopolsky Mark A.
Published: August 2006

Long‐term caloric restriction (CR) prolongs the lifespan in healthy insects, rodents, and nonhuman primates. We previously reported that long‐term CR improves motor performance but hastens clinical onset of disease in an animal model of amyotrophic lateral sclerosis (G93A mice). G93A mice overexpress the mutant human Cu/Zn‐SOD gene and show progressive lower motor neuron weakness and increased oxidative stress. To study short‐term (15 days) CR in the same animal model, we investigated the effect of transient caloric restriction (TCR) on paw grip endurance, clinical onset, disease progression (time from clinical onset to endpoint), and lifespan. Starting at age 40 days, 32 separately caged G93A mice were randomly divided into two groups: ad libitum (AL,n= 17; 10 females, 7 males) and TCR (n= 15; 6 females, 9 males) with a diet equal to 60% of AL. When the TCR mice lost 30% of their weight they were offered food AL until endpoint, otherwise all TCR mice were provided food AL from age 55 days until endpoint (i.e., range of TCR = 13–15 days). Paw grip endurance started to decrease significantly at age 96 days compared with baseline values for all the groups. TCR males reached clinical onset 5 days sooner than TCR females. Disease progression was 8 days faster in TCR mice than AL mice and 6 days faster in male mice than female mice. The probability of survival was significantly different between the groups, with the TCR males having a faster rate of reaching endpoint than TCR females, AL males, and AL females. We conclude that TCR hastens clinical onset of disease and shortens the lifespan in male, but not female, G93A mice. Moreover, TCR hastens progress of disease but has no effect on paw grip endurance. The female sex is protective against the detrimental effects of short‐term CR in G93A mice. Assuming we can extrapolate these results to humans, short‐term CR should be avoided in patients with amyotrophic lateral sclerosis, especially men. Muscle Nerve, 2006
Asymmetric sphincter innervation is associated with fecal incontinence after anal sphincter trauma during childbirth
Authors: Wietek Beate M. , Hinninghofen Heidemarie , Jehle Ekkehard C. , Enck Paul , Franz Heiko B.
Published: August 2006

Aims

Functional asymmetry of pelvic floor innervation has been shown to exist in healthy subjects, and has been proposed to be a predictor of increased risk for fecal incontinence in case of trauma. However, this remains to be shown for different clinical conditions such as traumatic childbirth.

Methods

A conventional surface EMG system was used to assess the innervation of the external anal sphincter. A symmetry index was used to define the relative EMG amplitude asymmetry of the external anal sphincter between 0 (symmetric) and 1 (asymmetric). Three cohorts were studied: 40 nulliparous women in the third trimester (Study 1), 15 primiparous women within 6 months following vaginal delivery without clinically apparent anal sphincter trauma (Study 2), and 50 women after childbirth‐related third or fourth degree perineal tear 6–12 months postpartum (Study 3). Furthermore, all women underwent conventional anorectal manometry.

Results

Sixteen or forty nulliparous women reported signs of fecal incontinence; however, relative asymmetry was not correlated to symptom severity (P = 0.345), and not to manometric measures (Study 1). In Study 2, Women who had suffered clinically apparent anal sphincter trauma (P = 0.07) tended to have a stronger association between incontinence and asymmetry. In Study 3, 19/50 women reported moderate to severe incontinence. Asymmetry and symptom severity were significantly correlated (P < 0.001). Patients with incontinence had a significantly higher asymmetry score than their continent counterparts.

Conclusion

Functional asymmetry of anal sphincter innervation is significantly associated with incontinence symptoms, but only after childbirth‐related sphincter injuries and therefore, should be regarded as an additional risk factor. Neurourol. Urodynam. © 2006 Wiley‐Liss, Inc.
Effective attacks in the salvo combat model: Salvo sizes and quantities of targets
Authors: Armstrong Michael J.
Published: August 2006

This article considers two related questions of tactics in the context of the salvo model for naval missile combat. For a given set of targets, how many missiles should be fired to produce an effective attack? For a given available salvo size, how many enemy targets should be fired at? In the deterministic version of the model I derive a simple optimality relationship between the number of missiles to fire and the number of targets to engage. In the stochastic model I employ the expected loss inflicted and the probability of enemy elimination as the main performance measures and use these to derive salvo sizes that are in some sense “optimal.” I find that the offensive firepower needed for an effective attack depends not only on a target's total strength but also on the relative balance between its active defensive power and passive staying power. © 2006 Wiley Periodicals, Inc. Naval Research Logistics, 2007
Current awareness: Pharmacoepidemiology and drug safety
Authors:   John Wiley & Sons, Ltd.
Published: August 2006

In order to keep subscribers up‐to‐date with the latest developments in their field, John Wiley & Sons are providing a current awareness service in each issue of the journal. The bibliography contains newly published material in the field of pharmacoepidemiology and drug safety. Each bibliography is divided into 20 sections: 1 Books, Reviews & Symposia; 2 General; 3 Anti‐infective Agents; 4 Cardiovascular System Agents; 5 CNS Depressive Agents; 6 Non‐steroidal Anti‐inflammatory Agents; 7 CNS Agents; 8 Anti‐neoplastic Agents; 9 Haematological Agents; 10 Neuroregulator‐Blocking Agents; 11 Dermatological Agents; 12 Immunosuppressive Agents; 13 Autonomic Agents; 14 Respiratory System Agents; 15 Neuromuscular Agents; 16 Reproductive System Agents; 17 Gastrointestinal System Agents; 18 Anti‐inflammatory Agents ‐ Steroidal; 19 Teratogens/fetal exposure; 20 Others. Within each section, articles are listed in alphabetical order with respect to author. If, in the preceding period, no publications are located relevant to any one of these headings, that section will be omitted.
Polymer electronic materials: a review of charge transport
Authors: Jaiswal Manu , Menon Reghu
Published: August 2006

This article presents an overview of the charge transport phenomenon in semiconducting polymer materials. In these disordered systems both intrinsic and extrinsic parameters play significant roles. In general, π‐electron delocalization, interchain interaction, band gap, carrier density, extent of disorder, morphology and processing of materials determine the electrical and optical properties. The chemical structure, especially the role of side groups, is quite important in both physical and processing properties. The nature of charge carriers and their role in charge transport depend on the structure and morphology of the system. Hence in several semiconducting polymer devices, the correlations among structure, morphology and transport are rather strong. The dependence of carrier mobility on temperature and electric field needs to be understood in the framework of competing models based on carrier hopping, trapping/detrapping and tunneling. Exactly what determines the dispersive/nondispersive, polaronic and correlative transport regimes is yet to be quantified. An understanding of the carrier mobility in semiconducting polymers is necessary to optimize the performance of polymeric electronic devices. Copyright © 2006 Society of Chemical Industry
Sample preparation project for the subcellular proteome of mouse liver
Authors: Song Yanping , Hao Yunwei , Sun Aihua , Li Tao , Li Wenrui , Guo Lihai , Yan Yujuan , Geng Chao , Chen Ning , Zhong Fan , Wei Handong , Jiang Ying , He Fuchu
Published: August 2006

Organelle proteome has become one of the most important fields of proteomics, and the subcellular fractionation with high purity and yield has always been a challenge for cell biologists and also for the Human Liver Proteome Project (HLPP). The liver of a C57BL/6J mouse was chosen as the model to find the optimum method for subcellular preparation. The method we selected could obtain the multiple fractions including plasma membrane, mitochondria, nucleus, ER, and cytosol from a single homogenate. With the same procedure, it is for the first time that the preparation method of frozen homogenized livers was compared with that of the fresh livers and frozen livers. We systematically evaluated the purity, efficiency, and integrity by protein yield, immunoblotting, and transmission electron microscopy. Taken together, the method of multiple fractions from a single tissue is effective enough for subcellular fractionation of mouse liver. We give a selective sample preparation method for frozen homogenized livers, for rare clinical samples, which cannot easily be used for subcellular separation immediately. But the frozen livers are not recommended for organelles isolation. This result is especially useful for sample preparation of human liver for subcellular fractionation of HLPP.
A global proteomics approach identifies novel phosphorylated signaling proteins in GPVI‐activated platelets: Involvement of G6f, a novel platelet Grb2‐binding membrane adapter
Authors: García Ángel , Senis Yotis A. , Antrobus Robin , Hughes Craig E. , Dwek Raymond A. , Watson Steve P. , Zitzmann Nicole
Published: August 2006

Collagen‐related peptide (CRP) stimulates powerful activation of platelets through the glycoprotein VI (GPVI)‐FcR γ‐chain complex. We have combined proteomics and traditional biochemistry approaches to study the proteome of CRP‐activated platelets, focusing in detail on tyrosine phosphorylation. In two separate approaches, phosphotyrosine immunoprecipitations followed by 1‐D‐PAGE, and 2‐DE, were used for protein separation. Proteins were identified by MS. By following these approaches, 96 proteins were found to undergo PTM in response to CRP in human platelets, including 11 novel platelet proteins such as Dok‐1, SPIN90, osteoclast stimulating factor 1, and β‐Pix. Interestingly, the type I transmembrane protein G6f was found to be specifically phosphorylated on Tyr‐281 in response to platelet activation by CRP, providing a docking site for the adapter Grb2. G6f tyrosine phoshporylation was also found to take place in response to collagen, although not in response to the G protein‐coupled receptor agonists, thrombin and ADP. Further, we also demonstrate for the first time that Grb2 and its homolog Gads are tyrosine‐phosphorylated in CRP‐stimulated platelets. This study provides new insights into the mechanism of platelet activation through the GPVI collagen receptor, helping to build the basis for the development of new drug targets for thrombotic disease.
Relationship between fracture toughness and intrinsic deformation parameters in isotropic and flow‐oriented linear low‐density polyethylene
Authors: Na Bing , Lv Ruihua
Published: August 2006

The fracture toughness of isotropic and flow‐oriented linear low‐density polyethylene (LLDPE) is evaluated by the Essential Work of Fracture (EWF) concept, with a special setup of CCD camera to monitor the process of deformation. Allowing for the molecular orientation, flow‐oriented sample, prepared via melt extrusion drawing, is stretched parallel (oriented‐0°) and perpendicular (oriented‐90°) to its original melt extrusion drawing direction, respectively. The obtained values of specific EFW we are 34.6, 10.2, and 4.2 N/mm for the oriented‐0°, isotropic and oriented‐90° sample, respectively. With knowledge of intrinsic deformation parameters deduced from uniaxial tensile tests, moreover, a relationship between specific EFW we the ratio of true yield stress to strain hardening modulus σty/G is well established. It means that the fracture toughness of polyethylene is determined by both crystalline and amorphous parts, rather than by one of them. Moreover, the true yield stress seems to be nondecisive factors determining the fracture toughness of polyethylene. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 2880–2887, 2006
Gas transport in surface‐modified low‐density polyethylene films with acrylic acid as a grafting agent
Authors: Costamagna Vanina , Strumia Miriam , López‐González Mar , Riande Evaristo
Published: August 2006

The modification of polyethylene by the grafting of poly(acrylic acid) onto the surface of one of the faces of low‐density polyethylene films with UV radiation is reported. The transport of oxygen, nitrogen, carbon monoxide, carbon dioxide, methane, ethane, ethylene, propane, and argon across surface‐modified films containing 3.7% poly(acrylic acid) has been investigated at several temperatures. The layer of poly(acrylic acid) grafted onto the surface of one of the faces of the films reduces the permeability coefficient of the gases by a factor of about 1/6. The sharp drop in the gas permeability as a result of the poly(acrylic acid) layer may arise either from the formation of ordered structures of the grafted chains or from the development of highly crosslinked structures. The values of the polymer–gas enthalpic interaction parameter for the modified film are higher than those for the unmodified one. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 2828–2840, 2006
Containment system design
Authors: Leung Joseph , Greenfield Warren
Published: August 2006

This article deals with the design considerations for several plant containment systems that were installed as part of the emergency pressure relief system. In all cases, the quench tank approach with vapor suppression was utilized. The examples presented include: (1) multiple batch reactors handling vinyl monomers, (2) multiple initiator charge vessels, and (3) multipurpose batch reactors with possible Grignard‐type reactions. The design considerations include: quench fluid selection, sizing of the quench tank, fluid mixing, sparging dynamics, vapor condensation efficiency, and post relief heatup. © 2006 American Institute of Chemical Engineers Process Saf Prog, 2006
Improvement of insulin resistance by miracle fruit (Synsepalum dulcificum) in fructose‐rich chow‐fed rats
Authors: Chen Chang‐Chih , Liu I‐Min , Cheng Juei‐Tang
Published: August 2006

In an attempt to probe a new target to improve insulin resistance, miracle fruit (Synsepalum dulcificum) was employed to investigate the effect on insulin resistance induced by fructose‐rich chow in rats. Single oral administration of the powder of this miracle fruit decreased the plasma glucose in a dose‐dependent manner for 150 min in rats fed fructose‐rich chow for 4 weeks. Insulin action on the glucose disposal rate was measured using the glucose‐insulin index, the value of the areas under the curve of glucose and insulin during the intraperitoneal glucose tolerance test. Oral administration of miracle fruit (0.2 mg/kg) to fructose‐rich chow fed rats, three times daily for 3 days, reversed the raised value of the glucose‐insulin index, indicating that miracle fruit has the ability to improve insulin sensitivity. The plasma glucose lowering action of tolbutamide, induced by secretion of endogenous insulin, is widely used to characterize the formation of insulin resistance. The time for the loss of the plasma glucose lowering response to tolbutamide (10.0 mg/kg, i.p.) in fructose‐rich chow fed rats was markedly delayed after treatment with miracle fruit compared with the vehicle‐treated group. Thus providing supportive data that oral administration of miracle fruit could delay the development of insulin resistance in rats. Also, the in vivo insulin sensitivity was markedly raised by miracle fruit. In conclusion, the results suggest that miracle fruit may be used as an adjuvant for treating diabetic patients with insulin resistance because this fruit has the ability to improve insulin sensitivity. Copyright © 2006 John Wiley & Sons, Ltd.
Mass spectral characterization of ergot alkaloids by electrospray ionization, hydrogen/deuterium exchange, and multiple stage mass spectrometry: usefulness of precursor ion scan experiments
Authors: Mohamed Rayane , Gremaud Eric , Tabet Jean‐Claude , Guy Philippe A.
Published: August 2006

Six ergot alkaloids belonging to the lysergic acid derivatives (ergonovine (EGN) and methysergide hydrogen maleinate (MHM)) and peptide‐type derivatives (ergocristine (EGR), ergotamine (EGT), ergocornine (EGC) andα‐ergokryptine (EGK)) were studied by positive electrospray tandem mass spectrometry. The fragmentation mechanisms of these compounds were studied by collision‐induced dissociation (CID) using triple quadrupole and ion trap mass spectrometers, and the nature of the major product ions further confirmed by hydrogen/deuterium (H/D) exchange experiments. A common abundant product ion atm/z223 was characteristic of the two classes of ergot alkaloids. Therefore, a precursor ion scan ofm/z223 that triggers information data acquisition (IDA) in combination with CID experiments was used to identify other potential ergot alkaloids. Using this approach, it was possible to confirm the presence of ergosine, another peptide‐type ergot alkaloid, in a rye flour extract at trace levels. Copyright © 2006 John Wiley & Sons, Ltd.