bluuebunny/crossref_metadata_2025 huggingface dataset:
Does the nicotine patch help in the postoperative period for arterial vessel repair?
Authors: Battista Vince , Fanua Sione P. , Shaw Wilgis E. F.
Published: February 2008

This study attempts to determine whether a nicotine patch will affect the patency rate of the femoral artery anastomosis in a smoking rat model. Twenty‐four rats underwent a smoking protocol of 4 weeks of exposure to cigarette smoke in a smoking chamber at 1 hour per day, using a 1:10 dilution of unfiltered cigarette smoke. Each rat then underwent a femoral artery transaction and anastomosis. Postoperatively, the rats were divided into two groups of 12. Group I had no postoperative smoking or nicotine therapy. Group II had nicotine patch treatment only. The femoral artery was evaluated for flow 7‐days postoperatively. At the time of anastomosis, the femoral arteries were smaller in diameter, averaging 0.5 mm (0.4–0.7 mm) as opposed to the normal 0.75–1 mm. All anastomoses were patent at 5 min when the wound was closed. No difference in patency rate occurred with the use of the nicotine patch. © 2008 Wiley‐Liss, Inc. Microsurgery, 2008.
Harmonic suppression of bandpass filters using open‐circuited stubs
Authors: Chen Lih‐Shan , Lin Wen‐Jeng , Huang Tsung‐Hui , Houng Mau‐Phon , Fu Shen‐Li
Published: February 2008

In this article, a cascaded bandstop filter using quarter‐wavelength open‐circuited stub structure is employed to suppress the spurious passband at the second harmonic of the bandpass filter. The center frequency of the fabricated bandpass filter is at 0.9 GHz and the fractional bandwidth is 5%. The proposed bandpass filter shows 30 dB rejection at the second harmonic during the frequency range from 1.1 to 10 GHz. The measured frequency responses of the fabricated filter are in agreement with simulated results. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 863–865, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23226
An extended omnipotent Smith chart with active parameters
Authors: Wu Yongle , Huang Haiyu , Liu Yuanan
Published: February 2008

The lossy nonreciprocal transmission line (LNTL) model with active characteristic impedances and active load impedances is researched in this article. For solving LNTL problems involving active parameters, the previous presented omnipotent Smith chart (OSC) is extended its domain of application. Though the formation of expression is unchanged, the extended OSC (EOSC) shows different characteristics. The EOSC is especially significant for the application in oscillator design and amplifier stabilization. An EOSC can be easily generated using Matlab or Java for applications. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 896–899, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23229
A direct method to extract RF MOSFET model parameters using common source‐gate and source‐drain configurations
Authors: Lee Seonghearn
Published: February 2008

A direct extraction method is newly developed to determine RF MOSFET model parameters using two‐port parameter equation derived from two zero‐bias equivalent circuits under common source‐gate and source‐drain configurations. This method is much simpler and more accurate than conventional ones using common source‐bulk configuration, because parasitic resistances are directly extracted from low‐frequency data without a complicated linear regression of high‐frequency data and capacitances are directly determined without any inappropriate assumptions. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 915–917, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23231
Microstrip parallel coupled‐line bandpass filter with selectivity improvement using U‐shaped defected ground structure
Authors: Piscarreta Daniel , Ting Sio‐Weng
Published: February 2008

A novel defected ground structure (DGS) feedline element with two transmission zeros and flat passband is proposed. The zeros can be tuned individually by the DGS geometry to improve the low order filter's selectivity. A traditional microstrip parallel coupled‐line bandpass filter cascading this new element, not only achieves the selectivity improvement, but also its basic design formulation is retained. A prototype DGS filter was designed and tested to validate its performance. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 911–915, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23236
Coplanar antenna array design with stubs over dipoles for RFID applications
Authors: e Silva F. R. L. , de Melo M. T. , Lourenço M. D.
Published: February 2008

A new Coplanar Strip Antenna design is presented. This antenna is suitable for RFID tags, operating in the 2.4‐GHz range. Device was fabricated on RT6002 substrate of thicknessh= 1.5 mm. The input impedance control is based on the conformal mapping technique. A full‐wave EM simulator was used to obtain the frequency response. Simulated and experimental results are presented. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 877–879, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23238
A novel divide‐by‐3 Hartley injection‐locked frequency divider
Authors: Lee Chien‐Feng , Jang Sheng‐Lyang
Published: February 2008

This study proposes a new divide‐by‐3 CMOS injection locked frequency divider (ILFD) fabricated in a 0.18‐μm CMOS process and describes the operation principle of the ILFD. The ILFD circuit is realized with a Hartley CMOS LC‐tank oscillator with two injection MOSFETs. The self‐oscillating VCO is injection‐locked by third‐harmonic input to obtain the division order of three. Measurement results show that at the supply voltage of 1.5 V, the free‐running frequency is from 3.86 to 4.27 GHz. At the incident power of 6 dBm, the locking range is from the incident frequency 12.13–12.86 GHz. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 906–909, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23242
Modified maximally flat parallel‐coupled lines for band‐pass filter applications and miniaturizations
Authors: Liu Ji‐Chyun , Zeng Bing‐Hao , Chang Jun‐Mao , Chien Chi‐Hsun , Chang Chung‐Chi , Chang Dau‐Chyrh
Published: February 2008

The modified configurations of maximally flat parallel‐coupled lines (MF‐PCL) structure are introduced to improve the performance of the conventional MF‐PCL resonator. To obtain a higher rejection (−39 dB), symmetry response, wider band (BW about 32%), and less insertion loss (−0.4 dB) filters at central frequency 5.78 GHz, the modified MF‐PCL resonators by using enhanced coupling techniques are proposed herein. The size reduction of 50% is achieved. Results including surface current distributions and frequency responses are presented and discussed. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 902–906, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23243
Portable biometric system of high‐sensitivity absorption detection
Authors: Chen Der‐Chin
Published: February 2008

The purpose of this paper is to design a portable biometric system that can measure the amount of absorption of the visible collimated beam that passes by the sample to know the absorbance of the sample. The measured object in the system is the gold colloid that the sample produces after a biochemical reaction. After measuring the absorbance of the gold colloid, we can obtain the concentrations of the waiting‐measured sample and further obtain the concentration of chemical solution contained in the sample. Normal single optical path system has a sensitivity of 0.5%.The process of the double optical path method increases the opportunities that the visible collimated beam is absorbed, which raise the detection sensitivity of the system to a sensitivity of 0.1%. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 868–871, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23249
Closed‐form expressions for computation of mutual admittance of a class of gap‐coupled circular microstrip antennas
Authors: Chakravarty T. , Khah Sunil K. , De Asok
Published: February 2008

In this paper, a new set of expressions are presented, which leads to accurate estimation of the mutual admittance and mutual coupling thereof for gap‐coupled circular microstrip antennas. Unlike previous works, the field expressions for both the patches are obtained with respect to one coordinate system, and the circuit theory is used to obtain the admittance parameter. When this mutual admittance is converted to scattering parameters, we obtain the magnitude of mutual coupling. The results presented in the standard literature are compared with those obtained through the present formulation and the accuracy obtained is reasonably good. The method is also extended to incorporate the effects of shorting pins at the center of the two patches. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 924–927, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23251
A sectoral horn antenna based on the electromagnetic band‐gap structures
Authors: Zhao Zeyu , Deng Qiling , Xu Huiliang , Du Chunlei , Luo Xiangang
Published: February 2008

Recently, the electromagnetic band‐gap (EBG) material, also known as photonic crystals, has been successfully used to suppress surface‐wave for the patch antenna. In this article, a sectoral horn antenna with the mushroom‐like EBG material is designed to enhance its gain. A flange plate is attached to the horn antenna mouth and a mushroom‐like EBG material is sticked to the flange plate. Because of effective surface‐wave suppression, the simulant and test results show that the gain of this sectoral horn antenna has almost increased 1.0 dB within the frequency from 11.7 to 14.0 GHz. This kind of horn antenna has the potential application in mobile and satellite communications. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 965–969, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23254
A novel design on broadband circularly polarized microstrip antenna
Authors: Li Zhu , Guang‐Ming Wang , Xiang‐Jun Gao
Published: February 2008

A square array of air columns is embedded in a dielectric substrate to form the photonic‐bandgap (PBG) structure and the band‐gap of such a PBG structure is analyzed at first. Then a broadband circularly polarized antenna based on the PBG structure is introduced. Through selecting appropriate lattice period and air column radius, the surface wave can be suppressed effectively and the circularly polarized characteristic can be improved when the resonant frequency (f = 12.5 GHz) of the antenna fell in the band‐gap of the PBG structure. After calculating and testing, the 20.6% (VSWR [lt] 2) bandwidth and 27.4% 3‐dB axial ratio bandwidth are achieved, respectively. Such circularly polarized antenna can be used extensively in communications field. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 954–957, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23257
Waveguide power dividers using multiple posts
Authors: Akbarzadeh Ali Reza , Shen Zhongxiang
Published: February 2008

A new rectangular waveguide power divider using multiple posts is described in this paper. The waveguide power divider is easy to fabricate and is particularly suitable for substrate‐integrated waveguide (SIW) circuits. Two designed examples are presented: one is a rectangular waveguide power divider using nine posts along theE‐plane and the other is a SIW waveguide power divider in which three inductive via holes are used. The measured results for the two designed power dividers are presented and compared with the simulated ones by Ansoft's high‐frequency structure simulator, and good agreement is observed. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 981–984, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23259
Compact wideband DGS lowpass filter with modified microstripline
Authors: Or Y. C. , Leung K. W.
Published: February 2008

A compact microwave lowpass filter with three transmission zeros is designed using the defected ground structure (DGS). The microstripline section above the DGS region is modified to obtain remarkable slow‐wave and bandgap effects. An equivalent lumped L–C circuit model is presented. Reasonable agreement among the simulated, modeled, and measured results is obtained. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 974–977, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23263
A symmetric log‐periodic balun for ultra‐wideband application
Authors: Chen Chu‐Yu , Ye Shu‐Hao
Published: February 2008

Compared with the conventional log‐periodic balun, the design of a symmetric log‐periodic balun can provide better performance over the entire designed band. A novel ultra‐wideband (UWB) balun with 3–6 GHz passband is demonstrated for UWB applications. The problems of fabrication and measurement of the conventional log‐periodic balun operated at higher frequency problems can be further improved. The magnitude and phase difference between two output ports are kept balancing at higher band edge portion. The measured amplitude imbalance is about ±1.1 dB with a corresponding phase difference about ±4°. The bandwidth of the balun is around 70%. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 947–948, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23264
A high‐power Cartesian feedback transmitter including a compact inverted Doherty amplifier
Authors: Cho Hanjin , Kim Min‐su , Jeong Jong‐hyuk , Van Juho , Jung Sung‐chan , Park Hyunchul , Lim Kyung‐hoon , Kwon Sung‐wook , Kim Jae Young , Song Sung Chan , Park Cheon‐Seok , Yang Youngoo
Published: February 2008

A high‐power Cartesian feedback transmitter including a compact inverted Doherty amplifier is presented. The system efficiency was further improved using a bias line adjustment method for the compact inverted Doherty amplifier. After the bias line adjustment from a λ/4 line for the Doherty amplifier, a power‐added efficiency (PAE) of 6.9% points was improved from 41.3 to 48.2% at an output power level of 45 dBm. The whole Cartesian feedback transmitter system exhibited an efficiency of 40% and an adjacent channel leakage ratio of‐51 dBc at an output power of 45 dBm for 859 MHz band π/4‐DQPSK applications. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 944–946, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23265
A compact meandering bandpass filter with dual passband performance for 2.4/5.7 GHz WLANs
Authors: Kuan Hon
Published: February 2008

In this letter, a compact dual‐band bandpass filter (BPF) using the meandering stepped impedance resonators (MSIRs) for the wireless local area networks (WLANs) is proposed. The dual‐band performance of the BPF is adjusted by the physical length (α) and impedance ratio (K) of the MSIRs. The proposed BPF is designed and fabricated, showing good dual‐passband responses at 2.4/5.7 GHz and a high isolation between the two passbands. The overall circuit size of the BPF is much smaller than the previous work. Good agreement with response of electromagnetic (EM) simulation and measurement is obtained. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 969–971, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23267
Fourth‐order accurate sub‐sampling for finite‐difference analysis of surface plasmon metallic waveguides
Authors: Hu Bobo , Sewell Phillip , Wykes James G. , Vukovic Ana , Benson Trevor M.
Published: February 2008

Recently, particular attention has been given to metallic waveguides supporting surface plasmons as promising components for integrated optical devices. However, the use of conventional numerical optimization tools for their design is hindered by the intensive computational effort associated with meshing down to the resolution of the thin metallic layer. In this study, the previous three‐point second order accurate finite‐difference formula suitable for correctly placing thin dielectric layers within coarse grids is extended to fourth order accuracy by using the generalized Douglas scheme, including the case when thin metallic layers supporting surface plasmons lie wholly between sample points. The improved formulation, combined with an imaginary distance procedure, is used to analyze the eigenmodes of both 2D and 3D thin metal films located upon dielectric substrates. Accurate calculation with coarser meshes than those required by the other standard differencing schemes is demonstrated, thus providing both a significant saving in computational resource and an extra degree of freedom in meshing such structures. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 995–1000, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23271
Novel substrate integrated folded waveguide filter
Authors: Alotaibi Sultan K. , Hong Jia‐Sheng
Published: February 2008

In this study, a novel substrate integrated folded‐waveguide resonator filter is presented and an aperture coupling between adjacent resonators is introduced, which is characterized using full‐wave EM simulations and verified experimentally. A demonstrator of two‐pole substrate integrated folded‐waveguide resonator filter of this type has been designed, fabricated, and tested. As an example, a two‐pole BPF centered at 4.675 GHz with a fractional bandwidth of 7.4% is designed, fabricated, and measured. Simulations and experimental results are presented to validate the design and to show the advantages of this type of filter. The simulated and measured results show an excellent agreement. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1111–1114, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23272
Design of compact stop‐band extended microstrip low‐pass filters by employing mutual‐coupled square‐shaped defected ground structures
Authors: Boutejdar A. , Makkey M. , Elsherbini A. , Omar A.
Published: February 2008

A new technique to reduce the size, improve the rejection in the stop‐band of a low‐pass filter using modified defected ground structure (DGS) is proposed. An equivalent circuit model is used to study the DGS characteristics. The parameters are extracted by using a simple circuit analysis method. Several comparisons between the EM‐simulations and the circuit simulations of the new structure are demonstrated to show the validity of the proposed equivalent circuit model. We demonstrated that the filter can provide a sharp transition domain and a wide rejection in stop‐band. To further verify the new technique, a filter employing the new deformed DGS is fabricated and measured. The agreement between the simulation and the measured results confirms the effectiveness of the proposed concept. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1107–1111, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23273
Low‐loss and broadband BGA package transition for LTCC‐SiP applications
Authors: Kangasvieri T. , Halme J. , Vähäkangas J. , Lahti M.
Published: February 2008

A high‐performance broadband ball‐grid‐array (BGA) package transition was designed and implemented from DC up to the Ka‐band frequencies. The vertical BGA‐via transition path starts from an organic motherboard (PCB) and ends at the top surface of a low‐temperature cofired ceramic module package. To assess solder joint reliability, large plastic‐core solder balls with a diameter of 800 μm were employed. The measured insertion loss of the entire vertical transition path, including feedlines, was better than 0.5 dB (1 dB) up to 25 GHz (29 GHz). Moreover, an equivalent circuit model for the complete transition path was developed. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1036–1040, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23276
Implementation of rigorous EM simulations for design and production of narrow band waveguide diplexer
Authors: Markovic Dusan , Jokanovic Branka , Kiriazi John , Lubecke Victor
Published: February 2008

In this article the advanced modeling and simulation of narrow band waveguide diplexer for radio‐relay links at 13 GHz is presented. Three different electromagnetic simulation packages were used for design of diplexer with 0.76% of fractional bandwidth and 2% of channel spacing. Simulation tools are compared concerning their accuracy in the prediction of central frequency, bandwidth, insertion and return losses and out of band attenuation. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1032–1036, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23277
Multiband surface‐mount chip antenna integrated with the speaker in the mobile phone
Authors: Chang Chih‐Hua , Wong Kin‐Lu , Row Jeen‐Sheen
Published: February 2008

A surface‐mount chip antenna integrated with the speaker in the mobile phone for GSM/DCS/PCS/UMTS multiband operation is presented. The antenna is to be mounted on the top no‐ground portion of the system circuit board of the mobile phone as an internal multiband antenna, and the speaker in the mobile phone can be inset into the chip base of the antenna to achieve a compact integration of the antenna and the speaker. Moreover, the chip antenna occupies a small volume of 35.5 × 10 × 7 mm3 (about 2.5 cm3) only. Details of the proposed chip antenna are presented. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1126–1132, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23287
Dual‐band filter using equal‐length split‐ring resonators and zero‐degree feed structure
Authors: Fan J. W. , Liang C. H. , Wu B.
Published: February 2008

A compact dual‐band microstrip filter with equal‐length split‐ring resonators and 0°‐feed structure is proposed in this article. The frequency splitting effect of the equal‐length SRRs is described in detail. A 0°‐feed structure is introduced and applied to realize additional transmission zeros at finite frequencies. The measurement of the filter is in good agreement with the simulation. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1098–1101, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23288
A broadband dual‐fed notched suspended plate antenna
Authors: Kian Toh Wee , Ning Chen Zhi , Ming Qing Xian
Published: February 2008

A single‐layer dual‐fed suspended plate antenna (SPA) with a notched radiator and broad lateral width is presented for high gain and broad coverage applications. Both the impedance and gain bandwidths of the proposed antenna are increased by extending the radiation aperture, while the occurrence of high‐order modes is suppressed by using a dual‐feed structure and notching the edges of the radiator. For comparison, the performances of four other types of SPAs are also investigated numerically and verified experimentally. Given the information on the merits and weaknesses of these SPAs, antenna engineers can opt for the appropriate antenna with the desirable performance for their specific applications. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1093–1098, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23289
Microstrip‐fed circular slot antenna for circular polarization
Authors: Tseng Lin‐Yu , Han Tuan‐Yung
Published: February 2008

A printed slot antenna with broadband circular polarization (CP) is presented. The proposed antenna is excited by an L‐shaped strip with a taper end, connected in series to a microstrip‐line‐fed located along the diagonal line of the circular‐slot. The measured results demonstrated a CP and impedance bandwidth of around 44% and 38%, respectively. It is noted that the CP bandwidth of 44% is much larger than those of antennas found in the literature. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1056–1058, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23290
Miniaturized hexaband meandered PIFA antenna using three meandered‐shaped slits
Authors: Tang I‐Tseng , Lin Ding‐Bing , Chen Wen‐Li , Horng Jui‐Hong
Published: February 2008

A novel and compact hexaband meandered planar inverted‐F antenna with three meandered‐shaped slits is proposed, designed, and implemented. The proposed meandered PIFA antenna occupies a volume of 40 × 20 × 8 mm3, the top meandered patch radiator embedded with three simple meandered‐shaped slits, which separates the top meandered patch into four resonant paths to generate four resonant modes. The proposed hexaband antenna operates at covering the GSM‐900, GPS‐1575, DCS‐1800, PCS‐1900, ISM (2.400–2.4835 GHz), and WiMAX (2.305–2.69 GHz) bands for VSWR ≤ 2.5, and also more efficiently reduces 50% of the conventional meandered patch antenna size and broadens operational bandwidth. This compact low‐profile design shows characteristics of near‐omnidirectional radiation patterns with minimal hand effects, which is preferable for applications in wireless mobile communications. A good agreement between measurement and simulation is achieved. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1022–1025, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23292
Design procedure for active microwave filters using the high quality active negative capacitance circuit for RF low‐noise bandpass applications
Authors: Kaya Adnan
Published: February 2008

This article presents a new methodology based on active band pass filter. In the proposed design, a resonator consists of an active negative capacitor together with a conventional inductor represented. The active negative capacitor is made of a field‐effect transistor that exhibits negative capacitance and negative resistance. It can, therefore, compensate the loss of an inductor. Two pole active bandpass filter centered 1.3 GHz, with 3 dB bandwidth of 640 MHz, high gain 1.5 dB, including a very low‐noise active filter which exhibits a noise figure of 2.5 dB are realized in the fist part. Compared with the conventional BPF, the proposed design shows better gain, noise figure, and the return loss level. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1086–1093, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23296
Comment on “Compact Microstrip Bandpass Filter Using Composite Right/Left‐Handed Transmission Lines”
Authors: Perruisseau‐Carrier Julien
Published: February 2008

© 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1132, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23302
Synthesis formulas for conductor‐backed coplanar waveguide
Authors: Yildiz Celal , Turkmen Mustafa
Published: February 2008

Simple and accurate formulas are presented for the synthesis of conductor‐backed coplanar waveguide (CPW). These formulas are derived by applying function approximation and curve‐fitting technique to the respective quasi‐static analysis results. The results obtained from these formulas are compared with the results of quasi‐static analysis and experimental works available in the literature. Average percentage error is found to be better than 1% for 1086 conductor‐backed CPW samples having different electrical parameters and geometrical dimensions. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1115–1117, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23304
Dual band power amplifier in GaN technology
Authors: Colantonio Paolo , Giannini Franco , Giofrè Rocco , Piazzon Luca
Published: February 2008

Experimental results of a simultaneous dual band high efficiency harmonic tuned power amplifier in GaN HEMT technology are presented. The amplifier has been realized in hybrid form and the measured results shown a peak of 53% and 46% of drain efficiency with 33 dBm and 32.5 dBm output power in the first (at 2.45 GHz) and second (at 3.3 GHz) bands, respectively. Moreover, a zero transmission condition has been obtained, resulting in a measured value ofS21lower than −15 dB at 2.8 GHz. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1040–1042, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23308
Regulation of granulosa and theca cell transcriptomes during ovarian antral follicle development
Authors: Skinner Michael K. , Schmidt Michelle , Savenkova Marina I. , Sadler‐Riggleman Ingrid , Nilsson Eric E.
Published: February 2008

Coordinated interactions between ovarian granulosa and theca cells are required for female endocrine function and fertility. To elucidate these interactions the regulation of the granulosa and theca cell transcriptomes during bovine antral follicle development were investigated. Granulosa cells and theca cells were isolated from small (<5 mm), medium (5–10 mm), and large (>10 mm) antral bovine follicles. A microarray analysis of 24,000 bovine genes revealed that granulosa cells and theca cells each had gene sets specific to small, medium and large follicle cells. Transcripts regulated (i.e., minimally changed 1.5‐fold) during antral follicle development for the granulosa cells involved 446 genes and for theca cells 248 genes. Only 28 regulated genes were common to both granulosa and theca cells. Regulated genes were functionally categorized with a focus on growth factors and cytokines expressed and regulated by the two cell types. Candidate regulatory growth factor proteins mediating both paracrine and autocrine cell–cell interactions include macrophage inflammatory protein (MIP1 beta), teratocarcinoma‐derived growth factor 1 (TDGF1), stromal derived growth factor 1 (SDF1; i.e., CXCL12), growth differentiation factor 8 (GDF8), glia maturation factor gamma (GMFG), osteopontin (SPP1), angiopoietin 4 (ANGPT4), and chemokine ligands (CCL 2, 3, 5, and 8). The current study examined granulosa cell and theca cell regulated genes associated with bovine antral follicle development and identified candidate growth factors potentially involved in the regulation of cell–cell interactions required for ovarian function. Mol. Reprod. Dev. 75: 1457–1472, 2008. © 2008 Wiley‐Liss, Inc.
Motor unit recruitment and bursts of activity in the surface electromyogram during a sustained contraction
Authors: Riley Zachary A. , Terry Mary E. , Mendez‐Villanueva Alberto , Litsey Jane C. , Enoka Roger M.
Published: February 2008

Bursts of activity in the surface electromyogram (EMG) during a sustained contraction have been interpreted as corresponding to the transient recruitment of motor units, but this association has never been confirmed. The current study compared the timing of trains of action potentials discharged by single motor units during a sustained contraction with the bursts of activity detected in the surface EMG signal. The 20 motor units from 6 subjects [recruitment threshold, 35.3 ± 11.3% maximal voluntary contraction (MVC) force] that were detected with fine wire electrodes discharged 2–9 trains of action potentials (7.2 ± 5.6 s in duration) when recruited during a contraction that was sustained at a force below its recruitment threshold (target force, 25.4 ± 10.6% MVC force). High‐pass filtering the bipolar surface EMG signal improved its correlation with the single motor unit signal. An algorithm applied to the surface EMG was able to detect 75% of the trains of motor unit action potentials. The results indicate that bursts of activity in the surface EMG during a constant‐force contraction correspond to the transient recruitment of higher‐threshold motor units in healthy individuals, and these results could assist in the diagnosis and design of treatment in individuals who demonstrate deficits in motor unit activation. Muscle Nerve, 2008
Molecular evidence of the independent origin of multiple Wilms tumors in a case of WAGR syndrome
Authors: Uccini Stefania , Perotti Daniela , Colarossi Cristina , Stoppacciaro Antonella , Sardella Michele , Mannarino Olga , Collini Paola , Casieri Paola , Cozzi Denis , Amoroso Loredana , Spreafico Filippo , Radice Paolo , Dominici Carlo
Published: February 2008

Background

This study investigated the genetic events leading to tumorigenesis in a patient affected with WAGR syndrome who developed multiple distinct Wilms tumors (WTs).

Procedure and Results

At 1 year of age, the child developed two synchronous bilateral WTs that were resected by partial nephrectomy. Histologically, these tumors were fetal rhabdomyomatous nephroblastomas. Immunohistochemical study revealed the absence of nuclear expression of WT1 protein, while β‐catenin protein was expressed at nuclear level by the large majority of tumor cells. Molecular investigations of WT1 gene and exon 3 of β‐catenin (CTNNB1) gene detected no mutations. At 4 years of age, 28 months after the chemotherapy completion, a third WT was diagnosed in the left kidney, and surgically removed before any further chemotherapy. Nine months after surgery, a metastasis was detected in the left lung. Both the third renal tumor and the lung metastasis showed a blastema‐predominant morphology. Immunohistochemistry confirmed the lack of expression of WT1 protein, while β‐catenin protein was expressed at nuclear level by the large majority of tumor cells. Molecular analysis of the third renal tumor and the lung metastasis revealed a 4 bp deletion in exon 7 of WT1 gene, leading to a frameshift of the reading frame and to a premature stop of the translation (c.925_928delACTC, p.T309LfsX71); no mutations in the exon 3 of the β‐catenin gene were documented.

Conclusions

These data demonstrate that multiple WTs can arise as a consequence of different genetic events in a patient with genetic predisposition, such as WAGR syndrome. Pediatr Blood Cancer 2008;51:344–348. © 2008 Wiley‐Liss, Inc.
Short‐term follow‐up of patients with sickle cell disease and albuminuria
Authors: Alvarez Ofelia , Lopez‐Mitnik Gabriela , Zilleruelo Gaston
Published: February 2008

Background

Albuminuria with normal serum creatinine occurs frequently in patients with sickle cell disease (SCD), but the rate of progression to more advanced chronic renal disease is unknown. The purpose of this study was to investigate the rate of progression of children and young adults with SCD and albuminuria over time.

Procedure

Urine albumin/creatinine (A/C) ratios and serum creatinine were obtained serially. Serum cystatin C levels were determined in a subgroup of 20 patients.

Results

Of 38 patients with SCD who had albuminuria (30 with microalbuminuria and 8 with proteinuria), 10.5% had progressive disease during follow‐up of 20 ± 12 months. Progressive disease was observed in 2 of 30 patients with MA because MA worsened to either intermittent proteinuria (1 patient), or persistent proteinuria after 7 months follow‐up (1 patient). Two of eight patients with proteinuria worsened to nephrotic‐range after 8 and 17 months with elevations of serum creatinine. All eight patients with proteinuria were treated with angiotensin blockade and/or hydroxyurea. Of those, six patients responded to treatment with decreased albuminuria and no changes in serum creatinine. Serum cystatin C level trended to increase before serum creatinine in patients with proteinuria.

Conclusions

Patients with rapid progression to nephrotic‐range proteinuria showed decreased kidney function. Therefore, patients with albuminuria should be monitored closely for progression, and therapy with hydroxyurea and/or angiotensin blockade should be considered for patients who develop proteinuria. Serum cystatin C appears more sensitive than serum creatinine to detect early decrease in kidney function. Pediatr Blood Cancer 2008;50:1236–1239. © 2008 Wiley‐Liss, Inc.
Effect of annealing and orientation on microstructures and mechanical properties of polylactic acid
Authors: Yu Long , Liu Hongshen , Xie Fengwei , Chen Ling , Li Xiaoxi
Published: February 2008

Two types of polylactic acid (PLA) films (one amorphous and one semi‐crystalline) were produced by sheet extrusion. Talc was used as a nucleation agent for the semi‐crystalline PLA. The films were annealed above their Tg or were uniaxially orientated in two ways: (1) via a drawing system in front of the extruder and die or (2) via a three‐roller stretching system. The slower crystallization rate and lower melting stress of the PLA resulted in amorphous film using the drawing system. Annealing above Tg increased crystallinity and polymer chain relaxation, which resulted in increases in both strength and toughness. Stretching above Tg also produced simultaneous crystallization and chain relaxation, which resulted in increases in both modulus and toughness. Both modulus and tensile strength in the stretching direction were higher than in the crosswise direction. Talc acted not only as a rigid filler to reinforce the PLA, but also as a nucleation agent for the PLA, especially during annealing. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers
Local thermo‐oxidative degradation in injection molding
Authors: Schmiederer Dirk , Gardocki Aleksander , Kühnert Ines , Schmachtenberg Ernst
Published: February 2008

A loss in part properties and service life is caused by thermal, mechanical, and thermo‐oxidative stress during processing of thermoplastic materials. Process related thermal and mechanical stresses are inevitable. However, processing under exclusion of oxygen can reduce the thermo‐oxidative stress. A lower thermo‐oxidative stress can yield a higher transparency of optical parts, less reduction of average molecular weight for example in microinjection molding, and a longer service life due to less consumption of stabilizers during processing. For a cost‐effective and gentle process it is important to know at which step of processing the polymer is exposed to thermo‐oxidative degradation and where the oxygen comes from causing degradation. To study the local thermo‐oxidative stress, an injection molding machine was encapsulated and run under local exclusion of oxygen. As reported in this article, thermo‐oxidative degradation occurs in the plasticating unit due to oxygen from the surrounding air and oxygen dissolved in the polymer resin. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers
Evaluation of anilinopyrimidine and other fungicides for control of grey mould (Botrytis cinerea) in container‐grown Calluna vulgaris
Authors: McQuilken Mark P , Thomson J
Published: February 2008

BACKGROUND:Grey mould (Botrytis cinerea Pers. ex Fr.) is a damaging disease affecting container‐grown Calluna vulgaris (L.) Hull. Trials were conducted to test anilinopyrimidine fungicides (pyrimethanil, cyprodinil and mepanipyrim), azoxystrobin and tolylfluanid for crop safety on cultivars, and to evaluate spray programmes based on alternating these fungicides with different modes of action for disease control. Timing and application at different spray intervals were also investigated.

RESULTS:Cyprodinil was slightly phytotoxic on only one of the seven cvs tested. Alternating nine‐spray programmes of azoxystrobin with an anilinopyrimidine or tolylfluanid, or an anilinopyrimidine with tolylfluanid, with the first spray applied immediately after potting, were equally effective in reducing disease incidence and severity compared with untreated plants. Spray programmes of five or eight sprays, using an anilinopyrimidine and at least one other fungicide with a different mode of action, applied alternately or in blocks of two sprays of the same fungicide and immediately after potting, were equally effective in reducing disease. Omission of early fungicide sprays until 9 weeks after potting and subsequent alternate application of pyrimethanil and tolylfluanid with a different mode of action at 6 week intervals gave reduced disease control.

CONCLUSION:There is potential to use spray programmes based on alternating anilinopyrimidines with fungicides with a different mode of action to provide effective control of B. cinerea on C. vulgaris. Copyright © 2008 Society of Chemical Industry
Fluorinated phthalocyanines as molecular semiconductor thin films
Authors: Brinkmann H. , Kelting C. , Makarov S. , Tsaryova O. , Schnurpfeil G. , Wöhrle D. , Schlettwein D.
Published: February 2008

Thin films of perfluorinated phthalocyanines F16Pc show promise as molecular semiconductors in organic field effect transistors. A review is provided of growth studies and electrical characterization of presently discussed materials. Using this state‐of‐the‐art as a starting point the synthesis and position of energy levels of partly fluorinated Zn(II) phthalocyanines is described. Growth characteristics of vapour‐deposited thin films on inorganic and organic dielectrics are studied. Possibilities to use fluorinated phthalocyanines in technical applications of OFET are discussed. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Carbon nanotube transistors – chemical functionalization and device characterization
Authors: Balasubramanian Kannan , Lee Eduardo J. H. , Weitz Ralf Thomas , Burghard Marko , Kern Klaus
Published: February 2008

This review presents an overview of the recent progress made in the field of carbon nanotube (CNT)‐based field‐effect transistors (FETs). Starting from the simplest device architectures, various methods reported for fabricating CNT‐FETs are presented. The main focus is laid on the use of chemical functionalization strategies both at a tube and at a device level to improve the performance of the devices. In addition to solid dielectric gate insulators, the use of liquids or solid polymer electrolytes as effective electrochemical gating media is outlined. Following this, device parameters of the various CNT‐FETs are compared and discussed. Finally, the utility of scanning photocurrent microscopy as an efficient characterization tool to estimate electronic band‐profiles of CNT‐FETs is highlighted. The review concludes with future perspectives in this rapidly emerging field. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Polarization sensitive spectroscopy of charged quantum dots
Authors: Poem E. , Shemesh J. , Marderfeld I. , Galushko D. , Akopian N. , Gershoni D. , Gerardot B. D. , Badolato A. , Petroff P. M.
Published: February 2008

We present an experimental and theoretical study of the polarized PL spectrum of single semiconductor quantum dots in various charge states. We compare our polarization sensitive spectral measurements with a novel many‐carrier theoretical model. The model considers both the isotropic and anisotropic exchange interactions between all participating electron‐hole pairs. We demonstrate that lines emanating from evenly charged states are linearly polarized. Their measured polarization direction does not necessarily coincide with the traditional crystallographic direction. It depends on the shells of the single carriers which participate in the recombination process. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Magneto‐optical properties of quantum rods and superlattices
Authors: Schillak P. , Czajkowski G.
Published: February 2008

We show how to compute the optical functions (the complex magneto‐susceptibility, dielectric function, magneto‐reflection spectra) for semiconductor quantum rods (QRDs) and superlattices (SLs) exposed to a uniform magnetic field in the growth direction, including the excitonic effects. The method uses the microscopic calculation of nanostructure excitonic wave functions and energy levels, and the macroscopic real density matrix approach to compute the electromagnetic fields and susceptibilities. The electron‐hole screened Coulomb potential and the valence band structure are taken into account. The novelty of our approach is that the solution is obtained in terms of known one‐particle electron and hole eigenfunctions, those omitting the complicated problem of the center‐of‐mass and relative motion separation in the magnetic field. Our approach applies, first of all, for low dimensional systems (QDS, QRDs, nanorings etc.) where, due to confinement effects accompanied by the e‐h Coulomb interaction, the separation of the relative‐ and center‐of‐mass motion is not possible. The convergence of the proposed method is examined. Numerical calculations have been performed for a Ga1x Alx As/GaAs SL and a CdSe QRD. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Spectroscopic ellipsometry of materials for infrared micro‐device fabrication
Authors: Folks W. R. , Ginn J. , Shelton D. , Tharp J. , Boreman G.
Published: February 2008

For many common types of process materials used in the fabrication of infrared microelectronic devices there is a lack of information available in the literature regarding their thin‐film optical properties over the wavelength range of 2 to 30 micrometers. In this article, spectroscopic ellipsometry is used to determine room‐temperature optical constants in the infrared for a variety of organic and inorganic coatings commonly used in fabrication. Examples include coatings used for photolithography, coating, passivation, planarization, index matching, and stand‐off. Applications include infrared frequency selective surfaces, antennas, micro‐displays, and flexible substrates. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Experimental study of the systematic errors for a Mueller matrix double rotating compensator ellipsometer
Authors: Piller G. , Broch L. , Johann L.
Published: February 2008

The Mueller Matrix Ellipsometer based on the optical PC1SC2A arrangement has been developped by Collins a few years ago. We present systematic errors due to a shift of the azimuth of the optical elements (i.e. polarizer, analyzer, the two compensators). This ellipsometer is more sensible to an error due to a compensator than an error due to the analyzer or the polarizer. The errors on some coefficients mij cannot be cancelled but for the other, a four‐zone measurement method is proposed. A two zone method with A = P = ±45° is sufficient for an isotropic sample to eliminate the errors on ρpp. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Temperature‐dependent spectro‐ellipsometric studies of optical transitions near absorption edge of TlInS2
Authors: Shim Y. , Nishimoto Y. , Okada W. , Wakita K. , Mamedov N.
Published: February 2008

The temperature dependence of the absorption edge of the layered TlInS2 was studied in a region of the incommensurate phase by spectroscopic phase modulated ellipsometry (SPME) on (001) surfaces in incoherent reflection mode that was sensitive to both E⊥C* and E//C* components of the reflected light (C*: the direction bisecting the angle between two optic axes). The energy position of the absorption edge, which was obtained from the measured Ic signal, was found to exhibit an irregular behavior with temperature in a similar way with the obtained earlier temperature dependence of excitons. It is proposed that this behaviour reflects the changes in electronic spectrum due to the temperature phase transition while the peaking anomaly of the measured in‐layer‐plane optical anisotropy is mostly related with the spatial structure of the incommensurate phase. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Precise determination of layer structure with EUV ellipsometry data obtained by multilayer polarizing elements
Authors: Tsuru T. , Yamamoto M.
Published: February 2008

Results of model fitting analysis of a 40 nm thick Mo layer sample are presented showing high sensitivity of extreme ultraviolet (EUV) ellipsometry with use of multilayer polarizing elements of limited performance. For the analysis, published data of EUV ellipsometry and reflectometry measured at a photon energy of 97 eV were used. Double layer models with roughness well reproduced characteristic resonance‐like structures observed in the multiple angles of incidence ellipsome try including the sign conversions inΔ, which were remained unexplained. The analysis showed that a thin additional layer should exist on the Mo surface, thereby proved high structural sensitivity of EUV ellipsometry. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)