bluuebunny/crossref_metadata_2025 huggingface dataset:
On fractal FSS suitable for WLAN and WiMAX communication
Authors: Ray Arup , Kahar Manisha , Sarkar Debashree , Sarkar P. P.
Published: April 2015

Multiband properties of three different types of fractals namely Sierpinski Carpet, Koch Snowflake, and Sierpinski Gasket have been exploited. It is seen that all three fractal frequency selective surfaces (FSSs) on suitable optimization of their fractal geometry exhibit dual band properties of wireless local area network (WLAN), IEEE 802.11b standard, but at the fatal cost of large electrical size. In an attempt of making their size less, the Sierpinski Carpet and Koch Snowflake fractal looses their resonance properties partially at WLAN frequencies; however, the newly designed, modified Sierpinski Gasket FSS, marvelously exhibits stable resonance at WLAN frequencies with an additional resonance at WiMAX frequency, IEEE 802.16e standard. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1546–1550, 2015
A wideband EBG resonator antenna with an extremely small footprint area
Authors: Hashmi Raheel M. , Esselle Karu P.
Published: April 2015

An electromagnetic band gap resonator antenna (ERA) with an extremely small footprint is presented. The proposed ERA has a peak measured gain of 15.6 dBi and an excellent measured 3dB gain‐bandwidth of 27%. The four‐layer composite superstructure used in this ERA takes the shape of a circular disc with the ground plane radius equal to that of the superstructure. Its footprint area is only 1.7λ02 at the lowest operating frequency. The average measured aperture efficiency of this ERA is nearly 90%. The side lobe levels are well below −12 dB over most of the operating bandwidth and the cross polarization levels are below −17 dB. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1531–1535, 2015
An unequal Gysel power divider based on circuit transformation
Authors: Kim Young , Sim Seok‐Hyun , Yoon Young‐Chul
Published: April 2015

This article presents an unequal Gysel power divider (UGPD) based on circuit transformation, which is converted from a Π‐ to a T‐type circuit. The Π‐type circuit of a conventional unequal Gysel divider consists of two different value resistors and its connection transmission line. In the proposed T‐type circuit, the dummy transmission line and the other transmission line with shunt resistor at center position is connected in parallel. Theoretical analysis was performed to derive the design equations for the proposed circuit conversion. For the validation of the circuit transformation, the UGPD using a T‐type circuit at the center frequency of 2 GHz was fabricated and measured. The measured characteristics agreed well with the simulation results. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1529–1531, 2015
Selectable sectoral antenna array using a quadruple feeding network for item‐level tagging in UHF RFID applications
Authors: Lee Wang‐Sang , Yu Jong‐Won
Published: April 2015

For avoiding a dead zone where the tag cannot be detected in the ultrahigh‐frequency (UHF) radio frequency identification (RFID), a SELECTABLE SECTORAL ANTENNA ARRAY USING a QUADRUPLE FEEDING NETWORK FOR ITEM‐LEVEL TAGGING IN UHF RFID APPLICATIONS is presented. The proposed antenna array consists of a 2 × 2 circular polarized quadrifilar spiral antenna array and a quadruple feeding network for multiple beams. It generates single, dual, and quad beams with a hemispheric coverage by a beam switching, and its maximum gain and 3 dB beamwidth are approximately 7.8 dBic and 60°, respectively. Compared with the conventional antennas, the proposed antenna array provides the improved tag identification with the dead zone avoidance in the reading range. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1523–1526, 2015
Direct‐fed reduced size patch antenna using array of cSRR in the ground plane
Authors: Elsdon Michael , Yurduseven Okan
Published: April 2015

In this article, a novel design for a reduced size microstrip patch antenna is presented and discussed. It is demonstrated that by embedding an array of complimentary split ring resonators in the ground plane, size reduction of 11.2%, together with an increased bandwidth of 202.6% can be achieved. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1526–1529, 2015
WDM‐OFDMA‐PON uplink optical transmission using bandwidth enhanced injection‐locked FP‐LD
Authors: Yang Seung‐Min , Kim Chang‐Hun , Jung Sang‐Min , Han Sang‐Kook
Published: April 2015

We propose a scalable support WDM‐based orthogonal frequency division multiple access‐passive optical network uplink transmission system using an injection‐locked Fabry–Perot laser diode (IL‐FP‐LD). This system uses an injection‐locking technique to enhance the usable bandwidth by making stable channel states. By properly controlling the IL‐FP‐LD operation, the number of optical network units (ONU) within a wavelength can be increased, which improves the optical bandwidth efficiency for the uplink transmission. The experimental results show an enhanced modulation bandwidth of 3.5 GHz. Compared with a conventional RSOA which has a modulation bandwidth of 1.5 GHz, our scheme improves the number of ONUs that can be accommodated within a wavelength more than two times. The total discrete multitone signal received from the ONUs, with QPSK mapping on the subcarriers was 6.77 Gbps over a 23‐km standard single mode fiber transmission. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1727–1732, 2015
Low phase noise Ku‐band push–push oscillator based on compact spiral‐resonator array
Authors: Li Zhipeng , Huang Hongyun , Liu Yongzhi , Bao Jingfu
Published: April 2015

A low phase noise push–push oscillator using compact spiral resonator (SR) array is presented in this letter. The proposed SR array can provide high frequency selectivity in compact size due to its intrinsic source‐load coupling structure. In addition, the SR array acts as a phase coupling network to ensure the out of phase operation mode in two suboscillators. The proposed SR array has a very compact size of 0.17λg×0.17λg. A 14.2 GHz push–push oscillator based on this SR array has been designed and implemented. The measured phase noise is −108.35 dBc/Hz at 100 kHz offset frequency, and the suppression of fundamental frequency and the third harmonic are −23.16 dBc and −37.21 dBc, respectively. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1683–1686, 2015
Compact dual‐band bandpass filters based on a novel defected ground spiral resonator
Authors: Xiao Mi , Sun Guoliang , Xu Fang
Published: April 2015

A novel defected ground structure spiral resonator with two spiral stubs and a center stub was presented in this article. Full‐wave simulation was used to investigate the working principle of the resonator. The results show that the spiral resonator has two operating modes, so that it can produce two resonant frequencies. It is also found that it is convenient to control the two resonant frequencies by adjusting the dimensions of the two spiral stubs and the center stub. A dual‐band bandpass filter (BPF) was designed using two resonators of this type and a T‐shaped coupling node, having a bandwidth of 4.5% at 1.87 GHz and a bandwidth of 3.3% at 2.43 GHz. The measured results of the designed dual‐band BPF agree well with the simulated responses. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1636–1640, 2015
An algorithm of impairment aware routing for wavelength division multiplexed optical networks
Authors: Kaur Karamjit , Singh Hardeep
Published: April 2015

Development of wavelength division multiplexing technologies and increased transparency in the networks has tremendously increased the information carrying capacity of fiber optic networks. However, these networks are affected by accumulation of optical impairments along the lightpath resulting in degradation of signal being transmitted thereby creating inadequacy to meet quality of service requirements. In this article, effort has been put in to identify different parameters affecting the signal quality. A technique to measure these parameters and their application in connection provisioning is presented. Electrical postprocessing techniques are implemented to calculate quality of link path. The algorithm designed consider the quality of lightpath for connection provisioning for each connection requirement based on first fit, best fit, and shortest path principle. The performance of designed algorithm has been verified by presenting different quality conditions of transmission links and optimal results are obtained. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1632–1536, 2015
Slot antenna with multiband functionality in wireless industrial applications
Authors: Shafei Shahin , Sedgeechongaraluye‐yekan T.
Published: April 2015

A unique slot antenna, for multiband applications with asymmetric coplanar waveguide feed is proposed. Different form of strips is used as grounded slits for providing multiband functionality. By adopting the proposed strips length and size, much wider impedance band width is achieved in two bands. Beside that an asymmetric feeding method is applied with rectangular patch for generating new resonances and good matching. By utilizing this novel method, good impedance matching is seen in both bands. The antenna size is only about 40 × 40, which covers the frequency band from 4.8 to 6.5 GHz in band#1 and from 7.8 to 8.4 GHz in band#2 for VSWR <2. Furthermore, by variation of strips positions and patch lengths, the control of the impedance band width and resonances are steered. Both simulated and measured results are illustrated and compared with each other to guaranties antenna's performance. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1653–1655, 2015
Implementation of veriloga GaN HEMT model to design RF switch
Authors: Majumdar Shubhankar , Bag Ankush , Biswas Dhrubes
Published: April 2015

GaN HEMT model has been implemented in designing of RF switch through VerilogA. The VerilogA model is formed by experimental data as obtained from DC and RF characteristics of the HEMT. A look‐up‐table based VerilogA model has been prepared to simulate the RF switch in Cadence's spectre. The simulated value of the switch property i.e. isolation and insertion loss is found to be −40 dB to −35 dB and −0.5 dB to −2.5 dB, respectively in the 0.5–2.5 GHz frequency range. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1765–1768, 2015
Miniaturized band‐pass filter based on composite right‐/left‐handed transmission‐line unit cell
Authors: Pandey Arvind Kumar , Gaurav Yatindra , Chauhan R. K.
Published: April 2015

This article presents the design and implementation of a band‐pass filter using a novel composite right‐/left‐handed (CRLH) structure. To minimize the overall size of filter, the concept of CRLH metamaterial is used. Only one unit cell of CRLH is used in this filter to reduce size. The proposed CRLH structure for this filter shows smaller size than the filters designed using traditional methods. The designed filter is simulated and, thereafter, validated by physical realization and its testing. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1713–1717, 2015
p‐i‐n diode phase shifter in waveguide structure
Authors: Parnes Michael , Vendik Orest
Published: April 2015

A calculation procedure is proposed to design the p‐i‐n diode phase shifter based on the waveguide transmission line. The laboratory sample of five‐bit phase shifter designed using the proposed procedure was fabricated and measured at 32–36 GHz. It provides the following phase shifts bits: 11°, 22°, 45°, 90°, 180°. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1666–1671, 2015
Development of the antipodal Vivaldi antenna for detection of cracks inside concrete members
Authors: Moosazadeh Mahdi , Kharkovsky Sergey
Published: April 2015

Ultrawide band (UWB) nondestructive testing and evaluation techniques can provide the detection of defects and damages in construction materials and members. The development of UWB antennas with proper dimensions and high performance for these systems is one of the major challenges. In this letter, an antipodal Vivaldi antenna (AVA) has been developed to be used in UWB techniques for nondestructive detection of cracks in concrete members. To obtain a desirable antenna performance including the wider impedance bandwidth, the higher directivity, and higher front‐to‐back ratio rectangular‐shaped slits (RSS) and a half‐circular‐shaped lens (HCSL) have been added in the design of a conventional tapered slot AVA. A parametric study on the dimensions of the slits is provided to optimize performance and size of the proposed antenna. The optimum size of the proposed antenna is 40 × 80 × 0.508 mm3, and it operates over the frequency range from 3.4–40 GHz. It is shown that the RSS increase impedance bandwidth especially at the lower frequencies. Directivity of the proposed antenna at higher frequencies has been increased by the HCSL. The feasibility of the proposed antenna for nondestructive evaluation of concrete members is demonstrated by investigation into its performance with concrete specimens possessing an air‐gap inside a concrete specimen. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1573–1578, 2015
Development of high gain multiband antenna with centre‐offset copper strip‐based periodic structure
Authors: Islam M. T. , Alam M. S. , Misran N. , Ismail M. , Yatim B.
Published: April 2015

In this article, two coplanar waveguide‐fed high gain multiband antennas with and without uniplanar copper strip‐based electromagnetic band gap (CS‐EBG) structure are proposed for portable wireless applications at 2.1, 2.4, 3.5, 5.2, 5.4, and 5.8 GHz. The initial multiband antenna is realized by patch‐ground shape modification and open‐ended rectangular slot insertion on the patch. The two layer uniplanar CS‐EBG structure is composed of square ring periodic elements of copper strips of different widths and gaps. The top unit cells are placed at an offset position with respect to the bottom layer, which is new technique applied to obtain multiple resonances from such a simple and compact planar structure. The antenna, when combined with the CS‐EBG structure, still preserved its multiband characteristics and produced directional pattern because of the reflecting property (like artificial magnetic conductor, AMC) of the CS‐EBG/AMC structure behind it, which was donut and omnidirectional shape in case of the antenna alone. The initial antenna gain is 5 dBi while the final antenna gain is improved to approximately 12 dBi at the first band and more than 6 dBi at other bands. Thus, the developed square ring copper strip structure is very effective to improve the antenna performances and finally resulted in a high gain antenna. Both of the configurations with and without the CS‐EBG/AMC are fabricated and tested, and the measurements are well agreed with the simulations. Despite of the slight frequency shifting, the antenna is still suitable for the portable wireless operation such as Wi‐Fi, WiMax, WLAN/HIPERLAN and even for LTE/4G technology at some frequencies. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1608–1614, 2015
Study of trapezoidal toothed log‐periodic antenna fed through tapered microstrip line‐to‐coplanar stripline transition
Authors: Patre Situ Rani , Singh Soni , Singh S. P.
Published: April 2015

The simulation and experimental studies of a wideband trapezoidal toothed log‐periodic (balanced type) antenna excited through tapered microstrip (MS) line to coplanar stripline (CPS) transition (balanced type feed) are presented in this paper. Effect of the balanced type feed on the performance of antenna is discussed. The tapered MS line provides impedance matching between CPS transition, which is connected to antenna and 50‐Ω coaxial cable. A quarter‐wavelength radial stub at the output end of transition is responsible for field transition. The simulated reflection coefficient‐frequency characteristic of the combination of the antenna and tapered MS line‐to‐CPS transition is compared with the corresponding characteristic of the antenna fed through microstrip‐to‐parallel strip balun. Further, the simulated input and radiation characteristics of the antenna fed through the proposed transition are also compared with corresponding experimental results. The antenna along with transition achieves simulated reflection coefficient bandwidth (reflection coefficient ≤ −10 dB) of 7.67:1 (0.9–6.9 GHz). The simulated peak realized gain and radiation efficiency vary in the range 0.25−5.6 dB and 71−95%, respectively over the operational bandwidth of the antenna‐transition combination. The simulated input and radiation characteristics of the proposed antenna are nearly in agreement with the corresponding measured results. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1671–1677, 2015
Wideband RCS reduction and gain enhancement microstrip antenna using chessboard configuration superstrate
Authors: Zheng Yue‐jun , Gao Jun , Cao Xiang‐yu , Li Si‐jia , Li Wen‐qiang
Published: April 2015

A novel design for wideband radar cross section (RCS) reduction and gain enhancement microstrip antenna is proposed. Two 180° phase difference and modified artificial magnetic conductor cells are utilized to combine chessboard configuration superstrate (CCS). The bottom side of CCS is etched slot and exploited to construct Fabry–Perot resonance cavity with ground plane of a microstrip antenna. The CCS can enable the primary antenna to obtain gain enhancement and RCS reduction simultaneously. Measured results show that the proposed antenna gain is enhanced by about 4.8 dB at 9.6 GHz and its 3 dB gain enhancement bandwidth is from 9.1 to 10.5 GHz. The half power beamwidth is suppressed from 101° to 12° in E‐plane, while it is only 14° in H‐plane, decreased by about 75° compared with the primary antenna. Meanwhile, the antenna RCS is dramatically reduced in a broad frequency range from 8.0 to 14.0 GHz, which contains the operation band of the proposed antenna. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1738–1741, 2015
Numerical and experimental verification of a trireflector compact antenna test range in the terahertz band
Authors: Lu Zejian , Liu Xiaoming , Wang Hai , Yao Yuan , Chen Xiaodong , Yu Junsheng
Published: April 2015

Numerical and measured results of the quiet zone performance of a trireflector compact antenna test range (CATR) system in the terahertz band are presented in this letter. A modular Gaussian beam (GB) analysis method, which consists of frame‐based Gabor transformation, GB reflection and a 3D GB diffraction technique, was implemented to evaluate the quiet zone performance. Compared to geometrical optics method, this method is valid in predicting the field distribution in the caustic region. Moreover, simulation results of the CATR system demonstrated a superior efficiency to the physic optics method, especially in the terahertz range. Measured results show that 70% quiet zone usage can be achieved with amplitude and phase ripples less than 1.2 dB and 15°, respectively in the central frequencies. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1686–1689, 2015
A novel finite element time domain method for nonlinear Maxwell's equations based on the parametric quadratic programming method
Authors: Zhu Bao , Yang Hongwei , Chen Jiefu
Published: April 2015

A finite‐element time‐domain method is developed for Maxwell's equations with nonlinear media. Compared with conventional nonlinear numerical methods, the proposed scheme is not based on iterations, but using the quadratic programming method. The nonlinear constitutive relations are treated as a series of linear complementary problems, thus, this scheme presents very good convergence behavior in computation. Numerical results demonstrate the validity of the proposed method. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1640–1645, 2015
16‐QAM all‐optical OFDM system performance evaluation with time and frequency offsets
Authors: Ali Mumtaz , Dai Bo , Wang Xu
Published: April 2015

In an all‐optical orthogonal frequency division multiplexing (AO‐OFDM) system, symbol time misalignment (STM) and subcarrier frequency offset (ScFO) between transmitter and receiver result in intercarrier interference (ICI) and intersymbol interference, leading to a degradation of the system performance. In this article, an analytical study of the impacts of STM and ScFO on the bit error rate (BER) performance of superchannel based on 16‐QAM modulated all‐optical OFDM transmitter with coherent detection is conducted. Under the condition BER = 10−3, maximum acceptable relative deviations for the STM and ScFO are 3.2 and 5.5% in AO‐OFDM system. A delay line interferometer (DLI)‐based ICI suppression method is proposed, and the results demonstrate that the tolerances to relative deviations for the STM and ScFO increase to 29 and 10% without cyclic prefix. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1593–1597, 2015
Modified theta‐shaped monopole antenna with defected ground structure for UWB applications
Authors: Singhal Sarthak , Singh Amit Kumar
Published: April 2015

A compact modified theta‐shaped monopole antenna for ultrawideband communication is presented. It consists of a modified theta‐shaped radiator fed with a modified microstrip feedline and rectangular notch‐loaded quarter elliptical coplanar waveguide ground plane. An impedance bandwidth of 4.35–20.75 GHz (131%) below −10 dB reflection coefficient line is achieved. The designed antenna structure has nearly omnidirectional radiation pattern in H‐plane and bidirectional pattern in E‐plane. The cross polarization level is also 20 dB lesser than copolarization level in every direction at lower frequencies. The performance of the designed antenna structure for three substrate materials, that is, FR‐4 epoxy, carbon nanotubes, and Ni0.2Co0.2Zn0.6Fe2O4, are also studied. The experimental and simulation results are found to be in good agreement. The designed antenna structure has advantage of wider bandwidth along with smaller dimensions as compared to previously reported monopole structures. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1625–1632, 2015
Analysis of shoot‐through current of supply modulator for envelope‐tracking techniques
Authors: Yoo Jinho , Yoon Seokhyun , Lee Changhyun , Park Changkun
Published: April 2015

In this work, we analyze the conduction and switching losses of a supply modulator for envelope‐tracking techniques. In particular, the conduction and switching losses in the class‐D chain of the supply modulator are calculated to enhance the efficiency of the supply modulator. From the calculated results, the number of stages and fan‐out in the multiple stages of the class‐D chain are optimized. To verify the feasibility of the analyzed results, we designed a supply modulator using a 180‐nm RF CMOS process. From the measured results, we successfully prove the feasibility of the analyzed results. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1579–1983, 2015
Compact SPDT switchable bandpass filter with single and differential outputs
Authors: Chen Chang‐Sheng , Lin Yo‐Shen
Published: April 2015

A single‐pole‐double‐throw (SPDT) switchable bandpass filter (BPF) based on capacitively loaded multicoupled line is proposed. The output port can be designed as either single‐ended or differential one. The proposed multifunctional circuit can effectively integrate the functions of SPDT RF switch, BPF, and balun. Compact size and good performance are achieved. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1705–1707, 2015
Novel multipulses technology for pulse laser radar
Authors: Chen Xiangcheng , Wang Keyi , Mei Tao , Wang Shaoping
Published: April 2015

A novel unequal spacing multipulses technology for pulse Laser Radar was proposed in this article. Data accumulation technology is an efficient method to improve signal‐to‐noise ratio due to different statistical characteristics between the echo signal and the noise. Traditional multipulses technology using equal spaces multipulses always leads to outputs once the time window has pulses no matter the number of pulses. We proposed a method using unequal spaces multipulses technology to improve the poor performance of the equal space multipulses technology, that is, if and only if the time window had special number pulses, the novel system would have output signal. We discussed the method to generate unequal spacing multipulses serials first, and then the algorithm to deal with the echo signals was also illustrated. Both simulation and experimental results showed the validity of our algorithm. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1614–1620, 2015
A −187.7‐FoM V‐band low‐power CMOS VCO using modified fT‐doubler with current‐reused technique
Authors: Chen Jian‐Ying , Chou Hung‐Ting , Chiou Hwann‐Kaeo
Published: April 2015

A modified fT‐doubler with current‐reused technique is proposed to realize a low power and low phase noise V‐band voltage controlled oscillator (VCO) in a standard 1P9M 90‐nm CMOS. The proposed technique not only increases the operation frequency but also reduces the DC power consumption at millimeter‐wave frequencies. The short circuit unity gain frequency fT of the modified fT‐doubler yields a 31% improvement compared to that of conventional one. Measurement result shows that the designed VCO achieves a phase noise of −115.4 dBc/Hz at 10‐MHz offset under a low power consumption of 2 mW. The figure‐of‐merit is up to −187.7 dBc/Hz. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1752–1755, 2015
A matched RF charger for wireless RF power harvesting system
Authors: Lee Ji‐Hoon , Jung Won‐Jae , Jung Jin‐Woo , Jang Jong‐Eun , Park Jun‐Seok
Published: April 2015

In this article, special type of RF Charger is proposed for Wireless RF power harvesting system. RF charger is consisted of impedance matching circuit, full bridge CMOS rectifier, active diode, hysteresis switch, and DC–DC booster. The proposed RF charger is to obtain maximum available RF power through adjusting impedance matching circuitries. The proposed RF charger is matched to Korean WCDMA frequency band from 1960 to 1980 MHz. The minimum input RF power for charging 5 V battery is −10 dBm. The RF to DC conversion efficiency of the RF charger is 81% at 30 mA load current with 5 V battery, and the maximum output voltage is 5.5 V. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1622–1625, 2015
Design of super wideband hexagonal‐shaped fractal antenna with triangular slot
Authors: Shahu Babu Lal , Pal Srikanta , Chattoraj Neela
Published: April 2015

A hexagonal‐shaped fractal antenna with triangular slot for super wideband (SWB) application is presented. The proposed antenna has total size of 20 × 33.4 × 1.57 mm3.The proposed antenna is designed of iterations of triangular slot on a hexagonal metallic patch with tapered microstrip line feed. A combination of semicircular and rectangular shaped partial ground plane is used to achieve a super wide bandwidth from 3 to 35 GHz with bandwidth ratio of 11.6:1. The antenna design, simulation and optimization are performed using IE3D Full Wave Electromagnetic Simulator. The proposed antenna is compact and has stable radiation pattern. The simulation and measured results are compared to demonstrate the performance of proposed antenna. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1659–1662, 2015
The microstructural correlates of T1 in white matter
Authors: Harkins Kevin D. , Xu Junzhong , Dula Adrienne N. , Li Ke , Valentine William M. , Gochberg Daniel F. , Gore John C. , Does Mark D.
Published: April 2015

Purpose

Several studies have shown strong correlations between myelin content and T1 within the brain, and have even suggested that T1 can be used to estimate myelin content. However, other micro‐anatomical features such as compartment size are known to affect longitudinal relaxation rates, similar to compartment size effects in porous media.

Methods

T1 measurements were compared with measured or otherwise published axon size measurements in white matter tracts of the rat spinal cord, rat brain, and human brain.

Results

In both ex vivo and in vivo studies, correlations were present between the relaxation rate 1/T1 and axon size across regions of rat spinal cord with nearly equal myelin content.

Conclusion

While myelination is likely the dominant determinant of T1 in white matter, variations in white matter microstructure, independent of myelin volume fraction, may also be reflected in T1 differences between regions or subjects. Magn Reson Med 75:1341–1345, 2016. © 2015 Wiley Periodicals, Inc.
Hyperactive mTORC1 signaling is unaffected by metformin treatment in aged skeletal muscle
Authors: Dungan Cory M. , Li Zhuyun , Wright David C. , Williamson David L.
Published: April 2015

Introduction: Appropriate activation of growth signaling pathways, specifically mammalian target of rapamycin complex 1 (mTORC1), is central to muscle mass and metabolism. The goal of these studies was to examine the effects of metformin on mTORC1 signaling in aged skeletal muscle in an attempt to normalize growth signaling. Methods: Aged (23m) and young (3m) male mice were fed a low fat diet without or with 0.5% metformin for up to 8 weeks, then mTORC1‐related signaling was examined in the plantar flexor complex. Results: Metformin had no significant effect on lowering body weight or muscle mass in aged animals, nor altered p70 S6 Kinase 1 (S6K1) and 4E‐binding protein 1 (4E‐BP1) phosphorylation. However, it significantly (P < 0.05) reduced body weight and lowered S6K1 and rpS6 phosphorylation in the young. Conclusions: Collectively, these data suggest metformin is ineffective at normalizing growth signaling in aged skeletal muscle. Muscle Nerve 53: 107–117, 2016
Standardized pelvic floor exercises improve stress urinary incontinence in women with intrinsic sphincter deficiency
Authors: Lehmann Corinne , Zipponi Ingrid , Baumann Marc U. , Radlinger Lorenz , Mueller Michael D. , Kuhn Annette
Published: April 2015

Objectives

Pelvic floor rehabilitation is the conservative therapy of choice for women with stress urinary incontinence (SUI). The success rate of surgical procedures in SUI patients with intrinsic sphincter deficiency (ISD) is low. The aim of this study was to analyse the effect of a standardized physiotherapy on patients with SUI and normotonic urethra and ISD.

Methods

In this study, 64 patients with ISD and 69 patients with normotonic urethra were enrolled. Maximum urethral pressure (MUCP) >20 cm H2O was considered as normotonic urethral pressure. Before and after physiotherapy MUCP was measured and cough testing was performed. Additionally, patient reported outcome was assessed using the King's Health Questionnaire (KHQ). For statistical analyses Excel 2010 (Microsoft Inc; Redmond, Washington) and SPSS 20 (SPSS Inc; Chicago, Illinois) for Windows were used. Power calculation was based on the primary endpoint incontinence impact and general health. For power calculation, GraphPad Statmate version 2.00 for Windows was used.

Results

Sixty‐four patients with ISD and 69 patients with normotonic urethra were included in the study. In SUI patients with normotonic and hypotonic urethra KHQ‐scores regarding the primary endpoins “general health” and “incontinence impact” significantly improved following standardized physiotherapy. In both groups MUCP increased after physiotherapy. In SUI patients with ISD standardized physiotherapy resulted in a decreased incidence of a positive cough test.

Conclusions

Standardized physiotherapy should be offered to patients with SUI and ISD. Long‐term results are subject to future studies. Neurourol. Urodynam. 35:711–716, 2016. © 2015 Wiley Periodicals, Inc.
A generalized technique for the encapsulation of nano‐sized NiO particles by styrene‐2‐hydroxyethyl methacrylate copolymer
Authors: Hossan M. Shamim , Rahman M. Abdur , Tauer Klaus , Minami Hideto , Ahmad Hasan
Published: April 2015

Encapsulation of nickel oxide (NiO) particles is of great interest to the researchers as such modification produces remarkable improvement in properties and versatility in application potential. In this investigation, nanosized NiO particles were first prepared by calcination of nickel hydroxide precursor obtained using a simple liquid‐phase process. The produced NiO particles were stabilized with oleic acid and then treated with tetraethylorthosilicate to produce NiO/SiO2 composite seed particles. Finally tri‐layered inorganic/organic composite particles were prepared by seeded copolymerization of styrene and 2‐hydroxyethyl methacrylate (HEMA) in the presence of NiO/SiO2 composite seed particles. The produced composite particles named as NiO/SiO2/P(S‐HEMA) were colloidally stable, and the obtained particles were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, X‐ray diffraction, X‐ray photoelectron spectroscopy and thermogravimetric analyses. Copyright © 2015 John Wiley & Sons, Ltd.
Effects of preparation methods on mechanical and tribological properties of SFCM/UP composites
Authors: Zeng Deming , Lv Jian , Liu Huashan , Du Rui , Lv Hui , Wei Chun
Published: April 2015

In this paper, the effects of preparation methods on mechanical and tribological properties of sisal fiber cellulose microcrystalline (SFCM)/unsaturated polyester (UP) composites were studied. Compared with the pure UP composites, the SFCM/UP composites prepared by in‐situ polymerization had greatly improved the mechanical and tribological properties. The impact strength, flexural strength, and flexural modulus of SFCM/UP composites with 2 wt% SFCM were 6.8 KJ/M2, 105.53 MPa, and 14.29 GPa, increased by 74.81%, 33.38%, and 7.36% in comparison with pure UP composites, respectively. Meanwhile, the volume wear rate of SFCM/UP composites at 100, 150, and 200°C decreased 50.40%, 52.39%, and 50.06%, respectively. These results suggested that the properties of SFCM/UP composites prepared by in‐situ polymerization were significantly improved, which may be attributed to the strong interface interactions between SFCM and UP matrix. Copyright © 2015 John Wiley & Sons, Ltd.
Inter‐laboratory comparison of UV‐light sources for testing of PV‐modules
Authors: Koehl Michael , Philipp Daniel
Published: April 2015

Durability assessment of materials exposed to natural weathering requires accelerated testing for verification of the ultraviolet (UV) stability, especially for polymeric material. The type approval testing of photovoltaic (PV) modules according to the standards International Electrotechnical Commission (IEC) 61215 and IEC 61646 includes a so‐called UV‐preconditioning test with a total UV dose of 15 kWh/m2 corresponding to natural weathering of about 3 months only. A serious UV test representing the service life needs to apply a much stronger UV‐intensity in a comparable way. Fraunhofer Institute for Solar Energy Systems performed an inter‐laboratory comparison of UV‐light sources in 13 accredited test labs and test centres of major PV module manufacturers. The most important topic was the spectral radiometric measurement of the used UV sources. Another main issue was the comparison with the integral measurements by the sensors used for control of the tests. Errors up to 120% were found. Copyright © 2015 John Wiley & Sons, Ltd.
Identification of proteins involved in inhibition of spheroid formation under microgravity
Authors: Riwaldt Stefan , Pietsch Jessica , Sickmann Albert , Bauer Johann , Braun Markus , Segerer Juergen , Schwarzwälder Achim , Aleshcheva Ganna , Corydon Thomas J , Infanger Manfred , Grimm Daniela
Published: April 2015

Many types of cells transit in vitro from a two‐ to a three‐dimensional growth, when they are exposed to microgravity. The underlying mechanisms are not yet understood. Hence, we investigated the impact of microgravity on protein content and growth behavior. For this purpose, the human thyroid cancer cells FTC‐133 were seeded either in recently developed cell containers that can endure enhanced physical forces and perform media changes and cell harvesting automatically or in T‐25 culture flasks. All cells were cultured for five days at 1g. Afterwards, a part of the cell containers were flown to the International Space Station, while another part was kept on the ground. T‐25 flasks were mounted on and next to a Random Positioning Machine. The cells were cultured for 12 days under the various conditions, before they were fixed with RNAlater. All fixed cultures showed monolayers, but three‐dimensional aggregates were not detected. In a subsequent protein analysis, 180 proteins were identified by mass spectrometry. These proteins did not indicate significant differences between cells exposed to microgravity and their 1g controls. However, they suggest that an enhanced production of proteins related to the extracellular matrix could detain the cells from spheroid formation, while profilin‐1 is phosphorylated.
The impact of carbon‐13 and deuterium on relative quantification of proteins using stable isotope diethyl labeling
Authors: Koehler Christian J. , Arntzen Magnus Ø. , Thiede Bernd
Published: April 2015

Rationale

Stable isotopic labeling techniques are useful for quantitative proteomics. A cost‐effective and convenient method for diethylation by reductive amination was established. The impact using either carbon‐13 or deuterium on quantification accuracy and precision was investigated using diethylation.

Methods

We established an effective approach for stable isotope labeling by diethylation of amino groups of peptides. The approach was validated using matrix‐assisted laser desorption/ionization time‐of‐flight (MALDI‐TOF) and nanospray liquid chromatography/electrospray ionization (nanoLC/ESI)‐ion trap/orbitrap for mass spectrometric analysis as well as MaxQuant for quantitative data analysis.

Results

Reaction conditions with low reagent costs, high yields and minor side reactions were established for diethylation. Furthermore, we showed that diethylation can be applied to up to sixplex labeling. For duplex experiments, we compared diethylation in the analysis of the proteome of HeLa cells using acetaldehyde‐13C2/12C2 and acetaldehyde‐2H4/1H4. Equal numbers of proteins could be identified and quantified; however, 13C4/12C4‐diethylation revealed a lower variance of quantitative peptide ratios within proteins resulting in a higher precision of quantified proteins and less falsely regulated proteins. The results were compared with dimethylation showing minor effects because of the lower number of deuteriums.

Conclusions

The described approach for diethylation of primary amines is a cost‐effective and accurate method for up to sixplex relative quantification of proteomes. 13C4/12C4‐diethylation enables duplex quantification based on chemical labeling without using deuterium which reduces identification of false‐negatives and increases the quality of the quantification results. Copyright © 2015 John Wiley & Sons, Ltd.
ON A PARTITION PROBLEM OF FINITE ABELIAN GROUPS
Authors: QU ZHENHUA
Published: April 2015

Let$G$be a finite abelian group and$A\subseteq G$. For$n\in G$, denote by$r_{A}(n)$the number of ordered pairs$(a_{1},a_{2})\in A^{2}$such that$a_{1}+a_{2}=n$. Among other things, we prove that for any odd number$t\geq 3$, it is not possible to partition$G$into$t$disjoint sets$A_{1},A_{2},\dots ,A_{t}$with$r_{A_{1}}=r_{A_{2}}=\cdots =r_{A_{t}}$.
Occupying Ukraine: Great Expectations, Failed Opportunities, and the Spoils of War, 1941–1943
Authors: Priemel Kim Christian
Published: April 2015

The attack against the Soviet Union was ideologically motivated, but the timing owed a great deal to military and economic considerations. German hopes largely focused on Ukraine, which was expected to be both a giant breadbasket and a reservoir of essential minerals. But plans for the economic exploitation of Ukraine were flawed from the beginning and remained inconsistent throughout the war. Substantial reconstruction efforts only began belatedly and were accompanied by brute force that combined economic logic with ideological zeal. The Nazi policies of racist repression and mass murder were, then, both a means ofandan obstacle to exploitation of the East. Yet, they were also successful: without the raw materials obtained from Ukraine, the Nazi war machine would have likely ground to a halt well before 1945. The cost of sustaining the German war effort was consequently borne, to a large extent, by the local population, which labored under appalling conditions both in the Reich and in Ukraine itself.
La question religieuse dans les
Considérations de Montesquieu
Authors: MANSUY DANIEL
Published: April 2015

L’article cherche à rendre compte du problème
religieux dans les Considérations de Montesquieu. La
question mérite notre intérêt compte tenu du
fait que Montesquieu ne prête pratiquement aucune attention
à la religion païenne dans son texte. Je tente
d’expliquer que ce silence n’est que relatif, et que les
inflexions de la pensée de Montesquieu à ce sujet
proviennent de choix stratégiques : Montesquieu est prudent
à l’égard de la religion. En même
temps, cela permet d’expliquer son silence en ce qui concerne
l’avènement de la religion chrétienne, envers
laquelle Montesquieu reste très critique.
Tensions entre la liberté et l’égalité dans leDiscours sur la liberté de penserd’Anthony Collins
Authors: NOISETTE KIM
Published: April 2015

LeDiscours sur la liberté de penser(1713) d’Anthony Collins revendique un droit égal, pour chaque être humain, d’examiner librement toute proposition. Pour autant, ce droit n’est pas très clair et Collins en défend successivement trois versions, donnant un rôle plus ou moins large à l’égalité. La tension entre la liberté revendiquée et une égalité dont la place varie va en s’accroissant au fil duDiscours. Il s’agit d’un exemple de développement encore embryonnaire d’une problématique qui, au fil du XVIIIesiècle, prendra une importance croissante.
The first 25 years of the hydrology of the Onyx River, Wright Valley, Dry Valleys, Antarctica
Authors: Chinn Trevor , Mason Peter
Published: April 2015

This paper summarises the first 25 years of data on hydrological work carried out each summer on the Onyx River, Wright Valley, by summer teams of field hydrologists of the New Zealand Antarctic Research Programme. The assignment expanded from the single water-level recording weir site near Lake Vanda to a second site near the Wright Lower Glacier together with a number of tributary stream measurements that were installed as the programme progressed. This work was carried out together with Dry Valleys lake level and glacial measurements and is as of much historical as of scientific interest as it contains much inaugural Antarctic hydrology work.
Safety of brilliant cresyl blue staining protocols on human granulosa and cumulus cells
Authors: Alcoba Diego Duarte , Conzatti Maiara , Ferreira Gustavo Dias , Pimentel Anita Mylius , Kussler Ana Paula , Capp Edison , von Eye Corleta Helena , Brum Ilma Simoni
Published: April 2015

The selection of human immature oocytes destined for in vitro maturation (IVM) is performed according to their cumulus–oocyte complex (COC) morphology. In animal models, oocyte pre-selection with brilliant cresyl blue (BCB) staining improves fertilization and blastocyst rates and even increases the number of calves born. As the granulosa cells and cumulus cells (GCs and CCs) have a close relationship with the oocyte and are available in in vitro fertilization (IVF) programs, applying BCB staining to these cells may help to elucidate whether BCB shows toxicity to human oocytes and to determine the safest protocol for this dye. GCs and CCs were isolated from 24 patients who underwent controlled ovarian stimulation. After 48 h, cells were exposed to: Dulbecco's Modified Eagle Medium (DMEM) with or without phenol red, DPBS and mDPBS for 60 min; 13, 20 and 26 μM BCB for 60 min; and 60, 90 or 120 min to 13 μM BCB. Cellular viability was tested using 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide (MTT) and trypan blue assays. The 20 and 26 μM BCB exposures resulted in lower cell viability, similar to when cells were exposed to BCB for 90 or 120 min. GCs and CCs viabilities were equal among control group and 13 μM BCB group after 60 min. BCB staining was not toxic to GCs and CCs when the regime of 13 μM BCB for 60 min was used. Due to the close molecular/biochemical relationship between these cells and the gamete, we propose that it is unlikely that the use of BCB could interfere with the viability/health of human oocytes.
The gender congruency effect during bilingual spoken-word recognition
Authors: MORALES LUIS , PAOLIERI DANIELA , DUSSIAS PAOLA E. , VALDÉS KROFF JORGE R. , GERFEN CHIP , BAJO MARÍA TERESA
Published: April 2015

We investigate the ‘gender-congruency’ effect during a spoken-word recognition task using the visual world paradigm. Eye movements of Italian–Spanish bilinguals and Spanish monolinguals were monitored while they viewed a pair of objects on a computer screen. Participants listened to instructions in Spanish (encuentra la bufanda / ‘find the scarf’) and clicked on the object named in the instruction. Grammatical gender of the objects’ name was manipulated so that pairs of objects had the same (congruent) or different (incongruent) gender in Italian, but gender in Spanish was always congruent. Results showed that bilinguals, but not monolinguals, looked at target objects less when they were incongruent in gender, suggesting a between-language gender competition effect. In addition, bilinguals looked at target objects more when the definite article in the spoken instructions provided a valid cue to anticipate its selection (different-gender condition). The temporal dynamics of gender processing and cross-language activation in bilinguals are discussed.
Why did they do that?: the methodology of reasons for action
Authors: O’Mahoney Joseph
Published: April 2015

‘Why did they do that?’ is one of the most common questions in International Relations. However, we cannot access other people’s reasons for action the same way that we perceive our own; we cannot introspect the reasons of other actors. This paper provides a unifying framework that delineates different types of knowledge claims regarding reason attribution. There are three possible methodological responses: (1) assume a possible reason and explain behavior in terms of that reason; (2) avoid the direct attribution of reason to individuals and locate explanatory leverage at an analytical level beyond the individual actor reason; and (3) use empirical evidence to adjudicate between possible reasons. Excessive skepticism of evidence of reasons lessens our understanding of the causes of action. When using empirical evidence, contrary to existing arguments, the paper shows that private settings do not systematically favor the true revelation of reasons. The paper also proposes a general principle, consilience, that allows evaluation of empirical claims of reason attribution that subsumes several existing methodological considerations, organizes them, and gives a consistent means of choosing between alternative reason attributions.