bluuebunny/crossref_metadata_2025 huggingface dataset:
Differential involvement of noradrenaline and nitric oxide in the regulation of vasopressin and oxytocin expression in rat supraoptic nucleus
Authors: Raison Danièle , Hardin‐Pouzet Hélène , Grange‐Messent Valérie
Published: February 2011

The hydroosmotic balance of the body is controlled by supraoptic nuclei and paraventricular nuclei of the hypothalamo‐posthypophyseal complex. In response to a physiological stimulation such as an osmotic stress, the supraoptic nuclei (SON) and the paraventricular nuclei undergo remarkable neurochemical and morphological changes. Therefore, the neuroendocrine hypothalamus is a particularly relevant model for studying the molecular and cellular mechanisms that govern these plasticity phenomena. Slices of rat hypothalamus maintained ex vivo by perfusion were used to study the short‐term involvement of noradrenaline (NA) and nitric oxide (NO) in the mechanisms of chemical plasticity of the SON. NA is involved early in the regulation of the expression of neuropeptides, including vasopressin (AVP) and oxytocin (OT). NO appears to be a key molecule in noradrenergic control of the chemical plasticity of the endocrine neurons: in the SON, NO is involved in the signaling pathway regulating the expression of AVP but not that of OT. © 2011 Wiley‐Liss, Inc.
Raman spectroscopy and support vector machines for quick toxicological evaluation of titania nanoparticles
Authors: Pyrgiotakis Georgios , Kundakcioglu O. Erhun , Pardalos Panos M. , Moudgil Brij M.
Published: February 2011

With the rapid development of nanotechnology products, there is a significant concern on the adverse effects that might be associated with them. Traditional biological assays are typically used to asses the toxicityin vitro. There are, however, questions regarding the suitability of these assays for this purpose, mainly due to the potential interaction of the particles with the utilized dyes. In addition, this process can be costly and time consuming, as a large number of different assays have to be used. To address some of these issues, Raman spectroscopy is used in this study to investigate the particle‐cell interactions. The spectrum of a living cell is a very complex and rich collection of data directly related to its chemical composition. To enhance the data resolution and make the detection of toxicity more robust, data‐mining techniques have been deployed. Furthermore, data‐mining techniques enable full automation of the entire process, minimizing user input. The Raman spectroscopy successfully evaluated the toxicity of TiO2nanoparticles by both the peak‐by‐peak analysis and with the implementation of support vector machines. The particles were found to display cytotoxicity after 36 h of exposure. The results were confirmed by MTT (3‐(4,5‐Dimethylthiazol‐2‐Yl)‐2,5‐Diphenyltetrazolium Bromide) assay and are in agreement with the existing literature on the subject. Overall, Raman spectroscopy appears to be among the very few techniques that exhibit low levels of interferences (obscuration, fluorescence, emission, etc.) from the particle addition. Since it does not rely on biomarkers, it can be usedin situfor an extended period with minimal effects on the cellular biochemistry. Copyright © 2011 John Wiley & Sons, Ltd.
Induction of tracheal stenosis in a rabbit model—endoscopic versus open technique
Authors: Steehler Matthew K. , Hesham Hosai N. , Wycherly Benjamin J. , Burke Kevin M. , Malekzadeh Sonya
Published: February 2011

Objective:

To evaluate and compare open versus endoscopic methods of inducing tracheal stenosis in the New Zealand white rabbit model.

Study Design:

Prospective randomized control, pilot study.

Subjects and Methods:

Fifteen New Zealand white rabbits were used in the study. Induction of tracheal stenosis was performed through an open incision in 6 rabbits, an endoscopic approach was utilized in 8 rabbits, and 1 rabbit served as the control. The open approach was performed by brushing the tracheal mucosa 10 times through an anterior tracheotomy with a nylon brush. The endoscopic method was acheived using a rigid bronchoscope and at a measured distance below the cricoid cartilage, passing the same nylon brush four times in each of four quadrants. Repeat endoscopies for evaluation of stenosis progression were performed at 2 and 3 weeks on all rabbits.

Results:

In the open group, we observed no stenosis with one mortality as a result of gastroenteritis due to antibiotic use. In the endoscopic group, all animals achieved some degree of stenosis by 14 days, with a mean airway narrowing of 43%. The two deaths in the endoscopic group occurred in the immediate postoperative period secondary to laryngeal edema. The endoscopic procedure was 5 minutes in duration.

Conclusion:

The endoscopic technique is an effective method of achieving circumferential tracheal stenosis in the rabbit model. Advantages include simple instrumentation, an endoscopic approach, potential for decreased costs, and more reliable results. Laryngoscope, 2011
A dual‐band bandpass filter based on dual‐band DBR
Authors: Hua Changzhou , Miao Chen , Xu Jin , Wang Hui , Wu Wen
Published: February 2011

A dual‐band bandpass filter using a new dual‐band dual‐behavior resonator (DBR) structure is proposed.The new dual‐band DBR consists of only two stopband elements connected in parallel. One is a uniform impedance open‐circuited stub and the other is a stepped impedance open‐circuited stub. The concept of stepped impedance resonator is utilized to realize the sencond band characteristics at desired frequencies. Experimental results in microstrip technology are presented, which validate our idea. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25822
Low‐power self‐injection‐locked CMOS armstrong voltage‐controlled oscillator
Authors: Jang Sheng‐Lyang , Liao Ying‐Hsiang , Chang Chia‐Wei , Juang M.‐H.
Published: February 2011

A 7‐GHz NMOS Armstrong cross‐coupled voltage‐controlled oscillator (VCO) is designed and implemented in a 0.18 μm CMOS one‐poly six‐metal (1P6M) process. The differential VCO uses two single‐ended Armstrong oscillators coupled via a pair of cross‐coupled transistors and a pair of varactors, and it also uses the self‐injection locking technique to reduce the phase noise. At the dc drain‐source voltage of 0.6 V, the output phase noise of the VCO is −110.9 dBc/Hz at 1‐MHz offset frequency from the carrier frequency of 7.45 GHz and the figure of merit is −186.26 dBc/Hz. Total VCO core power consumption is 1.614 mW. Tuning range is 1.16 GHz, from 6.42 to 7.58 GHz, while the control voltage was tuned from 0 to 2 V. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:728–731, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25826
Enhancement of FBG multiplexing capacity by the improved constructing spectrum method
Authors: Li P. C. , Zhao X. Z.
Published: February 2011

A method for multiplexing series FBG sensors, called the improved constructing spectrum method, is proposed. This method which does not ignore effects of spectral shadowing and multiple reflections can identify two serial high‐reflectance gratings working in the same channel. Thus the multiplexing capability of the sensing system is double. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:785–788, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25827
A novel reconfigurable multiband slot antenna fed by a coplanar waveguide using radio frequency microelectro‐mechanical system switches
Authors: Bemani M. , Nikmehr S.
Published: February 2011

This article presents the design of a novel reconfigurable multiband slot antenna fed by a coplanar waveguide using commercially available radio frequency microelectromechanical system (RF MEMS) switches.This antenna includes various combinations of GSM900, DCS1800, PCS1900, UMTS2000, GPS1575, and WLAN2400/5250/5800. Good radiation performances of the proposed antenna over the operating bands are also obtained. Detailed analysis is performed to characterize the effect of the switches by taking into consideration the switch model and wire bonding effects. The antenna was fabricated, and a good agreement is achieved between measurement and simulation. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:751–757, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25828
A novel wideband Wilkinson divider using parallel branch lines
Authors: Wu Peng , Zhang Yong , Zhang Qin
Published: February 2011

A novel wideband branch line Wilkinson divider is proposed. Branch lines are introduced to replace multiple resistors used in the multistage Wilkinson divider to increase the bandwidth of a single‐stage Wilkinson divider. To demonstrate its performance, a modified single‐stage Wilkinson divider with four branch lines has been fabricated and measured. Results show that the measured input return loss, output return loss, and isolation are better than 12.4, 11.6, and 15 dB, respectively, across a 72% bandwidth from 18.8 to 40 GHz. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:781–783, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25833
Wideband composite AMC surfaces for RCS reduction
Authors: Fu Yunqi , Li Youquan , Yuan Naichang
Published: February 2011

A composite artificial magnetic conductor (AMC) surface is presented for wide band radar cross section (RCS) reduction. The composite surface consists of two kinds of AMC cells with different resonance frequencies. The phase difference between them can be tuned to be within a range close to ±π over a wide bandwidth. Therefore, the reflections from these two different AMC cells cancel each other. The basic principle was discussed and a sample was measured. The results show that a nearly 10 dB RCS reduction was achieved with a 32% bandwidth. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:712–715, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25835
Critical coupling of the inverted‐F antenna by increasing effective inductance
Authors: Jeon Sinhyung , Kim Hyeongdong
Published: February 2011

In this letter, a novel feed structure that can achieve critical coupling in a planar inverted‐F antenna (PIFA) is proposed.The proposed structure considerably increases the effective inductance simply by inserting a branch capacitance between the feed line and the shorting pin of the conventional planar inverted‐F antenna without structural change to the antenna or ground plane. The extremely low profile PIFA for the GSM900 band is designed to verify the proposed feed structure for critical coupling. The designed PIFA fully covers the GSM 900 band for VSWR < 3. Also, a good omnidirectional radiation pattern was obtained at its operating frequency. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:737–740, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25839
Compact triple‐mode stub‐loaded stepped impedance resonator and bandpass filter
Authors: Deng Hong‐Wei , Zhao Yong‐Jiu , Zhang Lu , Zhang Xue‐Shun , Zhao Wei
Published: February 2011

A compact microstrip triple‐mode stub‐loaded stepped impedance resonator (SIR) and bandpass filter (BPF) are proposed in this letter.As a starting part of designing a triple‐mode BPF, the initial miniaturization dual‐mode folded T‐type open stub‐loaded SIR characteristic is investigated to choose its proper dimensions. Based on these predetermined dimensions of this dual‐mode resonator, a short‐circuited stub at the center plane is introduced in this resonator to generate an even mode and four transmission zeros which lead to a high rejection skirt and wide upper stopband outside the desired passband. A compact BPF with the triple‐mode SIR is simulated, fabricated and measured. The electromagnetic (EM) simulated and measured results are presented and an excellent agreement is obtained. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:701–703, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25841
A coupled dual‐u‐shaped monopole antenna for WiMAX triple‐band operation
Authors: Koo Tae Wan , Kim Dongsu , Ryu Jong In , Kim Jun Chul , Yook Jong‐Gwan
Published: February 2011

A coupled dual‐U‐shaped antenna for WiMAX triple‐band operation is presented.The proposed antenna is composed of two U‐shaped radiating elements based on a 50‐Ω microstrip‐fed line on FR4 substrate. By using the coupling between the inner and the outer U‐shaped antennas, which mainly generate three different resonant modes, the optimized matching characteristic is obtained. The experimental results such as the matching characteristic and radiation pattern of the proposed antenna are presented. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:745–748, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25842
Stacked arrangement of edge truncated elliptical and conventional circular patches for modern communication systems
Authors: Sekra Pratibha , Shekhawat Sumita , Bhatnagar D. , Saini J.S. , Saxena V. K.
Published: February 2011

The design and performance of a stacked arrangement of edge truncated elliptical patch and conventional circular patch antennas is proposed in this communication which is capable in providing improved impedance bandwidth with circularly polarized radiations. Both patches are designed on two independent glass epoxy FR‐4 substrates separated by thin air gap. The two patches are placed one over other in such a way that their centers also lie one over other. The size of upper circular patch is marginally larger than lower edge truncated elliptical patch which is acting as driver patch. Proposed arrangement of patches yield measured impedance bandwidth as high as 0.94 GHz with measured axial ratio bandwidth close to 3.33%. The measured gain and axial ratio results of proposed arrangement on patches are compared with simulated results. Co and cross polar patterns suggest that radiations are right circularly polarized in nature. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:947–952, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25846
Experimental validation of the NF–FF transformation with cylindrical scan from nonuniformly distributed data
Authors: Ferrara F. , Gennarelli C. , Guerriero R. , Migliozzi M.
Published: February 2011

The article concerns the experimental validation of two techniques for compensating the probe positioning errors in a near‐field–far‐field transformation with cylindrical scan using a nonredundant number of measurements.The former uses the singular value decomposition method and can be applied when the irregularly acquired samples lie on nonuniform rings, thus allowing to reduce the starting two‐dimensional problem into two independent one‐dimensional ones. The latter, based on an iterative technique, can be employed also when the previous hypothesis does not hold but requires the existence of a one‐to‐one correspondence, associating at each uniform sampling point the nearest irregular one. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:915–920, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25847
Synthesis of thinned linear antenna arrays using bees algorithm
Authors: Guney K. , Onay M.
Published: February 2011

In this article, we propose a method based on the bees algorithm (BA) to synthesize thinned linear antenna arrays with low sidelobe level.The BA is an optimization algorithm inspired by the behavior of the honey bees to find the optimal way of harvesting food resources around the hive. Several examples with different thinning percentages are given to show the effectiveness of the proposed method. The results of BA are compared with the results of real coded genetic algorithm, ant colony optimization, and iterative Fourier technique. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:795–799, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25850
Dual band space‐FED microstrip antenna arrays with orthogonal polarization
Authors: Bhide Rahul , Kumar Girish
Published: February 2011

A high gain dual band microstrip antenna array with orthogonal polarization is proposed using space‐fed configuration. The feed network in the array is eliminated which improves the efficiency. Simulated and measured results are presented. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:793–795, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25851
High‐integrated and small‐sized X‐band image rejection down‐converter MMIC using InGaP/GaAs HBT process
Authors: Wang Cong , Kim Nam‐Young
Published: February 2011

A fully differential X‐band image rejection down‐converter is fabricated using Hartley architecture with a total chip area of 2.6 × 1.1 mm2 in InGaP/GaAs HBT monolithic microwave integrated circuit technology.This down‐converter consists of two single‐balanced mixers, a differential intermediate frequency (IF) amplifier, a local oscillator quadrature generator, a three‐stage polyphase filter, and a differential voltage‐controlled oscillator. This down‐converter yields an image rejection ratio of over 30 dB, a conversion gain of over 30 dB, a noise figure of less than 3.5 dB, and an output‐referred 1 dB compression power (P1dB,OUT) of 2.5 dBm in the IF range 0.9‐2 GHz. The broadband image rejection characteristics over a frequency range of 1.1 GHz with a current consumption of 35 mA are achieved. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:789–793, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25852
A new compact antenna for digital television reception based on the Eleven antenna
Authors: Wang Ruoyu , Yang Jian
Published: February 2011

This article presents a new TV antenna based on the so‐called Eleven antenna for receiving digital television.The Eleven antenna is a log‐periodic folded dipole array, which can cover decade bandwidth. The new TV antenna, a variation of the Eleven antenna, is nearly planar and very compact, and therefore provides an additional alternative to the other common TV antennas like Yagi–Uda antenna and V‐dipole antenna. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:824–827, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25861
Modal characteristic equation and dispersion characteristics for an elliptical Bragg waveguide with a small number of claddings
Authors: Prajapati Y. , Singh Vivek , Saini J.P.
Published: February 2011

This article presents a rigorous analytical treatment of electromagnetic wave propagation in a new type of Bragg waveguide having elliptical core cross‐section surrounded by Bragg cladding layers. Using Maxwell's equations in elliptical coordinates, the field components are obtained that specially incorporate Mathieu (q > 0) and the modified Mathieu functions (q < 0). Using this equation the modal dispersion curves for even guided modes are obtained and plotted for different cladding eccentricity e. It is found that the dispersion curves are discontinuous and modes can exist only in particular wavelength bands. Finally, the modal birefringence in the said waveguide is also estimated. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:932–938, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25863
Small planar coplanar‐waveguide‐fed dual band‐notched monopole ultra‐wideband antenna
Authors: Trang Nguyen Dang , Lee Dong Hyun , Park Hyun Chang
Published: February 2011

A small coplanar‐waveguide‐fed monopole ultra‐wideband antenna with dual band‐notched characteristics is presented. By using a modified ground plane, the bandwidth of the antenna is extended by 28%. Two types of simple slots, L‐shaped and semicircular, are cut in the radiating patch to create dual band‐notched characteristics in 3.3–3.7 GHz for WiMAX and 5.15–5.825 GHz for WLAN, respectively. A good agreement between measured and simulated results were observed, showing broadband matched impedances from 2.8 to >12 GHz with VSWR <2, except for the two notches. The antenna has a small size of 17× 23 mm2, a stable gain, and a nearly omnidirectional radiation pattern in the entire bandwidth. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:920–924, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25872
Reduced‐size UWB uniplanar tapered slot antennas without and with corrugations
Authors: Wang Yifan , Bakar Aslina , Bialkowski Marek
Published: February 2011

This paper presents the design of compact uniplanar Tapered Slot Antennas (TSAs) without and with corrugations for operation in an ultra wide band (UWB) of 3.1–10.6 GHz.In the initial step, a conventional size‐reduced uniplanar TSA with an exponential taper is designed. The analysis of its radiation pattern shows that this TSA exhibits reduced directivity in the lower part of UWB. To overcome this shortfall, two modifications are investigated. One includes an introduction of constant or variable‐length narrow corrugations and the other one making elliptical cuts on conducting sides of the TSA. The modified TSAs maintain the initial UWB impedance characteristics. However, their behavior differs with respect to the radiation pattern and gain. The TSA with constant‐length corrugations shows similar radiation pattern characteristics as it's non‐modified predecessor while the TSA with variable‐length corrugations exhibits an almost constant directive radiation pattern across UWB. The gain of these two antennas oscillates with frequency leading to pulse distortion. The TSA with elliptical conductor cuts shows both constant directive properties and distortionless pulse transmission. This is confirmed by full‐wave EM simulations and measurements. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:830–836, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25878
Simple analytical calculation approach for input impedance of printed monopole and dipole antennas on thin substrate
Authors: Akan Volkan , Yazgan Erdem
Published: February 2011

Printed antennas are very popular for commercial and military RF (radio frequency)/microwave communication systems because there is an enormous evolution in printed circuit technology. In this study, printed monopole and filamentary excited dipole, which are basic models and easily applicable antennas within printed antennas, are analyzed, and analytical closed‐form relations have been obtained. The expressions obtained in this article have been verified by CST Microwave Studio simulation numerically, and experimentally measured and published results are available in the open literature. The compared results are close to each other. Therefore, these relations could be used as an initial design step just before detailed numerical analyses. Moreover, the given closed‐form formulations can be realized in CAD platforms easily for fast calculations. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:827–830, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25880
Novel microstrip dual‐band bandpass filter with wide stopband and high isolation
Authors: Guan Xuehui , Fu Wei , Li Guohui , Jiang Shan , Liu Haiwen
Published: February 2011

A novel microstrip dual‐band bandpass filter (BPF) using spur‐line‐loaded stepped‐impedance resonator (SIR) is proposed in this letter.Anti‐parallel coupled microstrip line is used to realize the dual‐band coupling and produce a transmission zero within two passbands. High isolation between two passbands is achieved. A spur‐line is loaded to the SIR to eliminate the higher spurious frequencies of the resonator. A dual‐band BPF with central frequencies of 2.4 and 5.6 GHz is designed. The designed filter has a wide stopband below −20 dB from 6 GHz to 11 GHz. Isolation between two passbands is below −60 dB. All the theoretical analysis and design procedures are discussed. The predicted performance of the dual‐band BPF is confirmed in experiment. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:803–806, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25881
A 20–30 GHz divide‐by‐3 ring‐oscillator‐based injection locked frequency divider with a wide locking range
Authors: Seo Seungwoo , Seo Hyogi , Jeon Sanggeun , Rieh Jae‐Sung
Published: February 2011

A 20–30 GHz divide‐by‐3 ring‐based injection locked frequency divider (ILFD) using NMOS loads for a wide locking range has been developed in a commercial 0.13‐μm Si RFCMOS technology.The ILFD shows a locking range up to 7.5 GHz (20.8−28.3 GHz, 30.5%) and operation range of 10 GHz (20.8–30.8 GHz, 38.8%) with DC power consumption of 13 mW and a 1.5 V supply voltage. The fabricated circuit occupies only 0.008 mm2 core area. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:389–841, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25883
Design of compact dual‐band chip antenna for WLAN/UWB applications
Authors: Park Sang Yong , Park Jong Kweon
Published: February 2011

This article describes a compact dual‐band chip antenna using folded‐loop metal pattern structure for WLAN/UWB applications.The folded‐loop metal pattern is embedded on the Taconic CER10 substrate to achieve a compact structure and two operating bands of WLAN and UWB. The proposed dual‐band chip antenna occupies a compact area of 6 × 6 mm and shows a low profile of 1 mm when mounted on the system circuit board of the mobile phone, making it suitable for thin mobile phone applications. Details of the proposed design are described and experimental results of the constructed prototype are presented. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:904–910, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25886
Slim wrapped inverted‐F antenna for GSM/DCS/PCS operation
Authors: Razali Ahmad R. , Bialkowski Marek E.
Published: February 2011

In this letter, the design of a super slim multiband wrapped inverted‐F antenna that covers the frequency bands allocated for GSM, DCS, and PCS wireless services is described. In the first step, the quarter‐wavelength (at 850 MHz) open‐end arm of an inverted‐F radiator is folded and meandered. Then, the antenna is wrapped using a fourth‐order folding technique to reduce its projection area to only 40 mm × 10 mm × 3 mm. Full wave electromagnetic (EM) simulations show that the antenna excites a lower mode resonance at ∼850 MHz and a higher one at about 1900 MHz. Its radiation pattern is nearly omni‐directional with a gain of about 2.5 dBi at the lower band and 4.6 dBi at the upper band. A prototype of the proposed antenna is fabricated and tested. A close agreement between the simulated and measured results is achieved. The measured 6‐dB return loss or voltage standing wave ratio (VSWR) 3:1 bandwidths for the lower and upper resonances is 200 MHz (770–970 MHz) and 280 MHz (1710–1990 MHz), respectively. These bandwidths are sufficient to cover GSM 850/900/1800/1900 MHz, DCS 1800 MHz, and PCS 1900 MHz bands. Because of its small volume, the proposed antenna is a very attractive candidate for modern slim portable transceivers. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:900–904, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25887
A V‐band CMOS sub‐harmonic mixer with integrated frequency doubler and 180° out‐of‐phase splitter
Authors: Lee Jen‐How , Chen Chi‐Chen , Lin Yo‐Sheng
Published: February 2011

A V‐band sub‐harmonic mixer with an integrated frequency doubler and a 180° out‐of‐phase splitter using standard 0.13 μm CMOS technology is reported. The sub‐harmonic mixer comprises a current‐reused bleeding mixer, a baseband amplifier, a 180° (Wilkinson‐power‐divider‐based) out‐of‐phase splitter, and a frequency doubler. The mixer consumed 31.5 mW and achieved input return loss at RF port better than −10 dB for frequencies from 49.8 to 63 GHz. At IF of 20 MHz, the mixer achieved maximum conversion gain of 9.5 dB at RF of 53 GHz. The corresponding 3‐dB bandwidth (ω3dB) of RF is 9.6 GHz (48.4–58 GHz). The measured LO‐to‐RF and LO‐to‐IF isolation were better than 50 dB over the frequency band of interest. In addition, the measured input 1‐dB compression point (P1dB) and input third‐order intermodulation point were −8 dBm and 2.2 dBm, respectively, at RF of 60 GHz. These results demonstrate the proposed mixer architecture is very promising for high‐performance V‐band RFIC applications. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:870–875, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25888
Volunteering time decisions: a multi‐factor experimental study
Authors: Carlson Jay , Huppertz John W. , Bowman R. Alan , Lambrinos James , Strosberg Martin A. , Kutzer Natalia A.
Published: February 2011

Non‐profit organizations often seek volunteers to help staff a fundraising event. In the present research, an experimental study assessed volunteering time decisions for a fundraising event following manipulations of opportunity cost valence, opportunity cost avoidability and question order involving donating time and donating money. Opportunity costs represent foregone alternatives sacrificed (e.g. working) when engaging in an activity (e.g. volunteering), with valence of the opportunity cost indicating the appeal (positive or negative) of the foregone alternative and avoidability of the opportunity cost suggesting how easy it would be to forgo the alternative. Prospective donors are often asked to consider both volunteering time and contributing money, and these two questions posed to individuals can be varied in terms of order. The results of the experiment revealed that individuals intended to volunteer the most time when an opportunity cost was negative and avoidable. The lowest time donation intentions occurred when an opportunity cost was positive and less avoidable with individuals also being asked about donating money prior to being asked to donate time. The results highlighted the importance to non‐profit firms of considering opportunity costs potential volunteers face and suggested care in structuring the order of questions involving time and money posed to those individuals. Copyright © 2011 John Wiley & Sons, Ltd.
Flame retardancy of polyamide 66 nanocomposites with thermally stable organoclay
Authors: Sheng Feifei , Tang Xiu‐Zhi , Zhang Sheng , Ding Xuejia , Yu Zhong‐Zhen , Qiu Zhaobin
Published: February 2011

A thermally stable imidazolium organoclay was synthesized to improve the flame retardancy performance of polyamide 66 (PA 66). To enhance flame retardancy of the PA 66/organoclay nanocomposite, the thermally stable organoclay was coated with monomethylol melamine (MMM) before melt‐compounding with PA 66. Transmission electron microscopy and X‐ray diffraction results confirmed the partial exfoliation of the organoclay in the PA 66 matrix. The use of the thermally stable organoclay did not affect the thermal stability of PA 66. The cone calorimeter results showed that the PA 66/orgnaoclay nanocomposite exhibited a greatly reduced heat release rate and a longer ignition time. However, the PA 66/organoclay binary nanocomposite had no rating in the UL‐94 vertical burning test because it did not extinguish until the entire polymer component was burnt. The PA 66 nanocomposite with 15 wt% of MMM‐coated organoclay performed better in the ignition resistance test than the PA 66/organoclay nanocomposite containing 15 wt% of melamine. Copyright © 2011 John Wiley & Sons, Ltd.
Tunnel current through virus particles between columnar structures in mesoporous silicon
Authors: Vashpanov Yuriy , Jung Jae‐Il , Dal Kwack Kae
Published: February 2011

Earlier we reported on a tunnel charge transport mechanism in mesoporous silicon with columnar structures under adsorption of plant nematode‐transmitted polyhedral (NEPO) viruses at room temperature. Additional experiments are performed in this paper to establish that this observed tunnel current is connected to a conduction path through virus particles. The plant NEPO viruses have an orbicular shape with a diameter of around 25–30 nm. This size is matched well to the porous size distribution in manufactured samples. The tunnel charge transport in semiconductor structures was not observed on loading protein macromolecules of smaller sizes. A physical mechanism of the observed phenomena can be interpreted to be the result of a shunting effect through virus particles between the two closely located columnar silicon structures. This effect is likely to result from double points at virus adsorption under the condition of matching of pore and virus sizes. The magnitudes of the tunnel barrier heights depend on the type of loaded plant viruses. The investigated columnar structures of mesoporous silicon can be used for research on the electrical properties of different viruses with corresponding sizes in the range of 20–30 nm. The existence of a tunnel current between columnar structures in mesoporous silicon under virus adsorption can be used as a simple method for their detection in the environment.
A facile approach for decorating quantum dots deep inside of anodically grown self‐organized TiO2 nanotubes
Authors: Shrestha Nabeen K. , Yoon Seog Joon , Lee Deok Yeon , Lee Misun , Lim Iseul , Sung MyungMo , Ahn Heejoon , Han Sung‐Hwan
Published: February 2011

We demonstrate here a simple but very effective approach to decorate anodically grown TiO2 nanotubes (NTs) uniformly with CdS and PbS quantum dots (QDs) deep inside the NT walls. This approach is based on SILAR (successive ionic layer adsorption and reaction) technique assisted with evacuation of the NTs. The basic idea of evacuation is to remove air pockets trapped inside the NTs so as to clear the passage for the penetration of QD precursors down the bottom of the NTs.

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(© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Comparison of two populations of curves with an application in neuronal data analysis
Authors: Behseta Sam , Chenouri Shojaeddin
Published: February 2011

Often in neurophysiological studies, scientists are interested in testing hypotheses regarding the equality of the overall intensity functions of a group of neurons when recorded under two different experimental conditions. In this paper, we consider such a hypothesis testing problem. We propose two test statistics: a parametric test similar to the modified Hotelling's T2 statistic of Behseta and Kass (Statist. Med. 2005; 24:3523–3534), as well as a nonparametric one similar to the spatial signed‐rank test statistic of Möttönen and Oja (J. Nonparametric Statist. 1995; 5:201–213). We implement these tests on smooth curves obtained via fitting Bayesian Adaptive Regression Splines (BARS) to the intensity functions of neuronal Peri‐Stimulus Time Histograms. Through simulation, we show that the powers of our proposed tests are extremely high even when the number of sampled neurons and the number of trials per neuron are small. Finally, we apply our methods on a group of motor cortex neurons recorded during a reaching task. Copyright © 2011 John Wiley & Sons, Ltd.
Formalizing interactive staged feature model configuration
Authors: Bagheri Ebrahim , Noia Tommaso Di , Gasevic Dragan , Ragone Azzurra
Published: February 2011

Feature modeling an attractive technique for capturing commonality as well as variability within an application domain for generative programming and software product line engineering. Feature models symbolize an overarching representation of the possible application configuration space, and can hence be customized based on specific domain requirements and stakeholder goals. Most interactive or semi‐automated feature model customization processes neglect the need to have a holistic approach towards the integration and satisfaction of the stakeholder's soft and hard constraints, and the application‐domain integrity constraints. In this paper, we will show how the structure and constraints of a feature model can be modeled uniformly through Propositional Logic extended with concrete domains, called Pscr(𝒩). Furthermore, we formalize the representation of soft constraints in fuzzy 𝒫(𝒩) and explain how semi‐automated feature model customization is performed in this setting. The model configuration derivation process that we propose respects the soundness and completeness properties. Copyright © 2011 John Wiley & Sons, Ltd.
EDXRF analysis of metal artefacts from the grave goods of the Royal Tomb 14 of Sipán, Peru
Authors: Galli A. , Bonizzoni L. , Sibilia E. , Martini M.
Published: February 2011

Several metallic sheets (about 1 mm thick) from the grave goods of the Royal Tomb 14 (Sipán, Peru) were characterised by energy dispersive X‐ray fluorescence analysis, using both a portable instrument and a capillary collimated spectrometer to investigate details, and micro‐Raman spectroscopy. The samples, belonging to the clothing of the warrior priest, resulted composed of thin copper sheets or tumbaga (natural alloy of copper, silver and gold). They were unearthed covered with typical green patina, formed during their long burial and characterised mainly by copper minerals, such as malachite, atacamite and magnetite identified with micro‐Raman spectroscopy. Due to deterioration of the original alloy, the artefacts analyzed in this work were rather fragile and could not resist hard polishing aimed at cleaning off corrosion products. So a non‐destructive qualitative EDXRF analysis was performed to identify the elemental composition of the metal alloy and a quantitative estimation was made applying the fundamental parameter method. The presence of superficial patina layer and the non‐homogeneous composition was also taken into account during calculation. The data obtained, compared to published results from several artefacts found in the nearby tombs, have been treated with a hierarchical statistic analysis. Copyright © 2011 John Wiley & Sons, Ltd.
ED‐XRF set‐up for size‐segregated aerosol samples analysis
Authors: Bernardoni Vera , Cuccia Eleonora , Calzolai Giulia , Chiari Massimo , Lucarelli Franco , Massabò Dario , Nava Silvia , Prati Paolo , Valli Gianluigi , Vecchi Roberta
Published: February 2011

The knowledge of size‐segregated elemental concentrations in atmospheric particulate matter (PM) gives a useful contribution to the complete chemical characterisation; this information can be obtained by sampling with multi‐stage cascade impactors. In this work, samples were collected using a low‐pressure 12‐stage Small Deposit Impactor and a 13‐stage rotating Micro Orifice Uniform Deposit Impactor™. Both impactors collect the aerosol in an inhomogeneous geometry, which needs a special set‐up for X‐ray analysis. This work aims at setting up an energy dispersive X‐ray fluorescence (ED‐XRF) spectrometer to analyse quantitatively size‐segregated samples obtained by these impactors. The analysis of cascade impactor samples by ED‐XRF is not customary; therefore, as additional consistency test some samples were analysed also by particle‐induced X‐ray emission (PIXE), which is more frequently applied to size‐segregated samples characterised by small PM quantities. A very good agreement between ED‐XRF and PIXE results was obtained for all the detected elements in samples collected with both impactors. The good inter‐comparability proves that our methodology is reliable for analysing size‐segregated samples by ED‐XRF technique. The advantage of this approach is that ED‐XRF is cheaper, easier to use, and more widespread than PIXE, thus promoting an intensive use of multi‐stage impactors. Copyright © 2011 John Wiley & Sons, Ltd.
Completely passive natural convection
Authors: Miklavčič M. , Wang C.Y.
Published: February 2011

We show that a unique, nontrivial, natural convection state exists under the Boussinesq approximation and completely passive boundary conditions.
Homogenization of a generalization of Brinkman's equation for the flow of a fluid with pressure dependent viscosity through a rigid porous solid
Authors: Savatorova V.L. , Rajagopal K.R.
Published: February 2011

In this paper we consider a generalization of Brinkman's equation governing the flow of an incompressible fluid through a porous medium to take into account the variation of the viscosity with the pressure. There is overwhelming evidence that the viscosity depends on pressure and that this dependence is exponential. We also consider the problem of a barotropic fluid in which both the viscosity and the density depend upon the pressure. We use a homogenization procedure, that exploits a multiple scale structure possessed by a solid porous medium, a `micro‐scale' comparable to the pore size and a `macro‐scale' associated with the global size of the body, to carry out a multiple‐scale asymptotic analysis. The ratio of the micro‐scale length to the macro‐scale length provides a small parameter that is a natural parameter with which to carry out a perturbation analysis. The perturbation procedure leads to a systematic methodology by means of which we can obtain equations at different orders of the small parameter. Specifically, we study some simple boundary value problems corresponding to one‐dimensional flows. We find that while the dependence of the viscosity on the pressure can have a significant effect on the nature of the solution, so much so that the solution is completely different in comparison to the constant viscosity case Brinkman's equation, we find that the dependence of the density on the pressure has little or no effect on the nature of the solution.
Extraction of Fatty Acids from Boletus edulis by Subcritical and Supercritical Carbon Dioxide
Authors: Vidović Senka , Mujić Ibrahim , Zeković Zoran , Lepojević Žika , Milošević Svetlana , Jokić Stela
Published: February 2011

Mushrooms contain many valuable compounds such as fatty acids, carbohydrates, lycopene, lovastatin, trace elements etc. As they are currently valued for biologically active substances, and as high pressure carbon dioxide fluid extraction has been documented as an effective method for preparing bioactive products from plant materials, subcritical and supercritical carbon dioxide extraction of Boletus edulis mushroom was performed. In the extracts obtained, the fatty acids were determined. Response surface methodology (RSM) was applied to investigate the effect of pressure and extraction time on the extraction yield. The analysis of variance showed that pressure and extraction time had a significant effect on the extraction yield in both investigated process. The interaction between pressure and extraction time had a significant effect only in supercritical extraction process of B. edulis. Higher extraction yields have been obtained by subcritical carbon dioxide, and higher linoleic acid content has been determined in extracts obtained by supercritical carbon dioxide.
Pregabalin for the discontinuation of long-term benzodiazepines use: An assessment of its effectiveness in daily clinical practice
Authors: Bobes J. , Rubio G. , Terán A. , Cervera G. , López-Gómez V. , Vilardaga I. , Pérez M.
Published: February 2011

Purpose

To evaluate the effectiveness and tolerability of pregabalin in the management of the discontinuation of benzodiazepines in long-term users.

Subjects and methods

We performed a 12-week, prospective, uncontrolled, non-interventional, and observational study in patients aged 18 years old or above, who met DSM-IV-TR criteria for benzodiazepine dependence without other major psychiatry disorder. Evaluations included the Benzodiazepine Withdrawal Symptom Questionnaire, the Hamilton Anxiety Rating Scale, the Clinical Global Impression Scale, and the Sheehan Disability Scale. A urine drug screen for benzodiazepines was performed at baseline and every 4 weeks thereafter. The primary effectiveness variable was success rate, defined as achievement of benzodiazepine-free status at week 12 according to the urine drug screen.

Results and discussion

The mean dose at week 12 was 315 (±166) mg/day. The success rate of the benzodiazepine taper in the primary efficacy population (n = 282) was 52% (95% confidence interval [CI], 46–58). Success rates for women and men were 58% (95% CI, 49–67) and 46% (95% CI, 38–55), respectively. The success rates did not differ according to either the benzodiazepine of abuse or the presence of other substance use disorders. Significant and clinically relevant improvements were observed in withdrawal and anxiety symptoms, as well as in patients’ functioning. At week 12, tolerability was rated as good or excellent by 90% and 83% of the clinicians and patients, respectively.

Conclusion

Our results suggest that pregabalin is an efficacious and well-tolerated adjunctive treatment for benzodiazepine withdrawal.
Psychotic-like experiences and depressive symptoms in a community sample of adolescents
Authors: Barragan M. , Laurens K.R. , Navarro J.B. , Obiols J.E.
Published: February 2011

Purpose

Studies of psychotic-like experiences (PLEs) within community samples of adolescents have explored predominantly positive experiences. There is a paucity of research examining the prevalence and correlates of negative PLEs, and whether particular subtypes of negative PLEs can be identified among the general population of adolescents. This study examined the association of both positive and negative PLEs with depressive symptoms, including detailed analysis of subtypes of positive and negative psychosis dimensions.

Method

A community sample of 777 adolescents (50.9% girls: mean age 14.4 years) completed a questionnaire assessing positive and negative PLEs and depressive symptoms.

Results

Principal component factor analysis identified four factors of positive symptoms (persecutory ideation, grandiose thinking, first-rank/hallucinatory experiences and self-referential thinking), and three factors of negative symptoms (social withdrawal, affective flattening, and avolition). Depressive symptoms were associated positively with persecutory ideation, first-rank/hallucinatory experiences, social withdrawal, and avolition, whereas grandiose thinking related negatively with depressive symptoms. Neither self-referential thinking nor affective flattening related to self-reported depression.

Conclusions

These findings support the view that not all types of positive and negative PLEs in adolescence are associated with depression and, therefore, they may not confer the same vulnerability for psychotic disorders.
Is There a Trade-off between Security and Liberty? Executive Bias, Privacy Protections, and Terrorism Prevention
Authors: DRAGU TIBERIU
Published: February 2011

I develop a game-theoretic model of an interaction between an antiterrorist agency and a terrorist organization to analyze how the probability of a terrorist attack varies when the level of privacy protections changes. I derive two implications. First, privacy and security from terrorism need not be in conflict: when accounting for strategic interactions, reducing privacy protections does not necessarily increase security from terrorism. Second, and more important, the antiterrorist agency will always want less privacy. The very agency whose expertise affords it disproportionate influence on policy making will prefer a reduction in privacy protections even when that reduction harms security from terrorism. The analysis has implications for understanding the relationship between government powers and civil liberties in the context of terrorism prevention and times of emergencies more generally.