bluuebunny/crossref_metadata_2025 huggingface dataset:
WWOX: Its genomics, partners, and functions
Authors: Del Mare Sara , Salah Zaidoun , Aqeilan Rami I.
Published: August 2009

The WW domain‐containing oxidoreductase (WWOX) spans one of the most active common fragile sites (CFSs) involved in cancer, FRA16D. WWOX encodes a 46‐kDa protein that contains two N‐terminal WW domains and a central short‐chain dehydrogenase/reductase (SDR) domain. Through its WW domain, Wwox interacts with its partners and modulates their functions. Our data indicate that Wwox suppresses the transactivation function of several transcription factors implied in neoplasia by sequestering them in the cytoplasm. Work from our laboratory and other research groups have demonstrated that Wwox participates in a number of cellular processes including growth, differentiation, apoptosis, and tumor suppression. Targeted deletion of the Wwox gene in mice causes increased spontaneous and chemically induced tumor incidence supporting bona fide tumor suppressor function of WWOX. Moreover, generation of the Wwox‐deficient mice uncovers, at least in part, some of the physiological in vivo functions of the WWOX gene. This review focuses on recent progress that elucidates Wwox functions in biology and pathology. J. Cell. Biochem. 108: 737–745, 2009. © 2009 Wiley‐Liss, Inc.
Nanoparticles as tools to study and control stem cells
Authors: Ferreira L.
Published: August 2009

The use of nanoparticles in stem cell research is relatively recent, although very significant in the last 5 years with the publication of about 400 papers. The recent advances in the preparation of some nanomaterials, growing awareness of material science and tissue engineering researchers regarding the potential of stem cells for regenerative medicine, and advances in stem cell biology have contributed towards the boost of this research field in the last few years. Most of the research has been focused in the development of new nanoparticles for stem cell imaging; however, these nanoparticles have several potential applications such as intracellular drug carriers to control stem cell differentiation and biosensors to monitor in real time the intracellular levels of relevant biomolecules/enzymes. This review examines recent advances in the use of nanoparticles for stem cell tracking, differentiation and biosensing. We further discuss their utility and the potential concerns regarding their cytotoxicity. J. Cell. Biochem. 108: 746–752, 2009. © 2009 Wiley‐Liss, Inc.
On the minimum degree of minimal Ramsey graphs
Authors: Szabó Tibor , Zumstein Philipp , Zürcher Stefanie
Published: August 2009

We investigate the minimization problem of the minimum degree of minimal Ramsey graphs, initiated by Burr et al. We determine the corresponding graph parameter for numerous bipartite graphs, including bi‐regular bipartite graphs and forests. We also make initial progress for graphs of larger chromatic number. Numerous interesting problems remain open. © 2009 Wiley Periodicals, Inc. J Graph Theory 64: 150–164, 2010
Diastereoselective synthesis of γ‐dispiroiminolactone bearing naphthalene or bipyridine pendant groups
Authors: Maghsoodlou Malek T. , Hazeri Nourollah , Habibi‐Khorassani Sayyed M. , Ziyaadini Morteza , Marandi Ghasem , Khandan‐Barani Khatereh , Ebrahimi Pouneh , Charati Faramarz Rostami , Sobolev Alexandre , Makha Mohamed
Published: August 2009

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Diastereoselective γ‐dispiroiminolactone products 4a, 4b, 4c, 4d, 4e, 4f, 4g, 4h, 4i, 4j, 4k, 4l, 4m were obtained from a condensation of the highly reactive 1:1 intermediate of isocyanides and acetylenic esters with aromatic α‐dicarbonyls compounds 3a, b. J. Heterocyclic Chem., (2009).
An efficient and stereoselective synthesis of pyrazolo[4,3‐c]pyridine derivatives under microwave heating
Authors: Peng Ju‐Hua , Hao Wen‐Juan , Tu Shu‐Jiang
Published: August 2009

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A practical, inexpensive, and rapid method for the stereoselective synthesis of pyrazolo[4,3‐c]pyridine derivatives via microwave‐assisted reactions of 3,5‐diarylidenepiperidin‐4‐ones with phenylhydrazine in ethylene glycol. This method has the advantages of good yield, operational simplicity, and simple purification procedure. J. Heterocyclic Chem., (2009).
Penta‐deuterated acid precursors in the pheromone biosynthesis of the Egyptian armyworm, Spodoptera littoralis
Authors: Muñoz Lourdes , Rosell Gloria , Guerrero Angel
Published: August 2009

Synthesis of penta‐deuterated intermediate precursors d5(E)‐11‐14:Acid (7), d5(Z)‐11‐14:Acid (10) and d514:Acid (12) of the pheromone of the Egyptian armyworm Spodoptera littoralis has been accomplished by a very convenient route starting from the commercially available 9‐dodecyn‐1‐ol. The processes occur with a high to excellent chemical and stereochemical yields and the compounds have been successfully used in the confirmation of the pheromone composition and biosynthesis of our strain. Copyright © 2009 John Wiley & Sons, Ltd.
[18F]/19F exchange in fluorine containing compounds for potential use in 18F‐labelling strategies
Authors: Blom Elisabeth , Karimi Farhad , Långström Bengt
Published: August 2009

Exchange of [18F]fluoride with 19F in various organofluorine compounds in concentrations ranging from 0.06 to 56 mM was explored. We aimed to explore whether exchange reactions can be a potential useful labelling strategy, when there are no requirement of high specific radioactivity. Parameters such as solvents, temperature, conventional vs microwave heating, and the degree of fluorine load in some aromatic and alkyl compounds were investigated with regard to radiochemical yield and specific radioactivity. A series of fluorobenzophenones (1–6), 1‐(4‐fluorophenyl)ethanone (7), various activated and deactivated fluoro benzenes (8–16), N‐(pentafluorophenyl)benzamide (17), (pentafluorophenyl)formamide (18), (tridecafluorohexyl)benzene (19) and tetradecafluorohexane (20) were subjected to [18F]/19F exchange. To test this strategy to label biologically active molecules containing fluorine atoms in an aryl group, two analogues of WAY‐100635 (21–22), Lapatinib (23), 2,5,6,7,8‐pentafluoro‐3‐methylnaphthoquinone (24) and 1‐(2,4‐difluorophenyl)‐3‐(4‐fluorophenyl)propan‐1‐one (25) were investigated. The multi‐fluorinated molecules containing an electron‐withdrawing group were successfully labelled at room temperature, whereas the monofluorinated, as well as those containing an electron‐donating group, required heating for the exchange reaction to take place. Copyright © 2009 John Wiley & Sons, Ltd.
Cosmogenic nuclide exposure ages from the ‘Parallel Roads’ of Glen Roy, Scotland
Authors: Fabel Derek , Small David , Miguens‐Rodriguez Maria , Freeman Stewart P. H. T.
Published: August 2009

The ‘Parallel Roads’ of Glen Roy, Scotland, are the shorelines of former ice‐dammed lakes created by the last glaciers to occupy the area. We use surface exposure dating with cosmic ray‐produced 10Be in quartz to provide the first numerical age control on the timing of formation of one of one of these shorelines and depositional features in Glen Roy. Four bedrock samples from the surface of the 325 m ‘Parallel Road’ yielded a mean formation age of ca. 11.5–11.9 ka. This age range confirms the long‐held view that the ‘Parallel Roads’ are Loch Lomond Stadial (ca. 12.9–11.5 ka) features. The age range reflects variation in currently available cosmogenic nuclide scaling schemes and the related 10Be production rates. Two samples from the surface of the Turret fan indicate that the 260 m lake drained before ca. 10.7–11.0 ka, while two samples from the Brunachan fan suggest that subaerial sedimentation occurred after ca. 9.7–9.9 ka. Copyright © 2009 John Wiley & Sons, Ltd.
Tip‐enhanced Raman spectroscopy for investigating adsorbed nonresonant molecules on single‐crystal surfaces: tip regeneration, probe molecule, and enhancement effect
Authors: Liu Zheng , Wang Xiang , Dai Ke , Jin Shan , Zeng Zhi‐Cong , Zhuang Mu‐De , Yang Zhi‐Lin , Wu De‐Yin , Ren Bin , Tian Zhong‐Qun
Published: August 2009

Tip, substrate, molecular species, and laser are the four main factors determining the detection sensitivity and spatial resolution of tip‐enhanced Raman spectroscopy (TERS). In this paper, we deal with the tip and molecular species. We will first introduce a simple method to regenerate Au tips fabricated by electrochemical etching for TERS to ensure good experimental reproducibility. Some criteria are proposed to choose molecular species as the probe molecules for reliable TERS investigation of the surface processes and TERS mechanism after a comparison of the TERS and SERS signal of benzenedithiol and 4,4′‐bipyridine. Then, high‐quality TERS signals of a series of molecules of oligo(phenylene ethynylene)s (OPEs) of different lengths adsorbed on a Au(111) single crystal surface are demonstrated. The possible explanation assisted by finite‐difference time‐domain (FDTD) simulation and quantum chemical calculation is used to understand the molecular length‐dependent change of the TERS signal. The potential application of TERS for studying systems related to molecular electronics is proposed. Finally, a method is proposed to calculate the tip enhancement for the nonresonant surface species in TERS. Copyright © 2009 John Wiley & Sons, Ltd.
Perfusion in hamster skin treated with glycerol
Authors: Zaman Raiyan T. , Parthasarathy Ashwin B. , Vargas Gracie , Chen Bo , Dunn Andrew K. , Rylander Henry G. , Welch Ashley J.
Published: August 2009

Background and Objective

The objective of this article is to quantify the effect of hyper‐osmotic agent (glycerol) on blood velocity in hamster skin blood vessels measured with a dynamic imaging technique, laser speckle contrast imaging (LSCI).

Study Design/Materials and Methods

In this study a dorsal skin‐flap window was implanted on the hamster skin. The hyper‐osmotic drug, that is, glycerol was delivered to the skin through the open dermal end of the window model. A two‐dimensional map of blood flow of skin blood vessels was obtained from the speckle contrast (SC) images.

Results

Preliminary studies demonstrated that hyper‐osmotic agents such as glycerol not only make tissue temporarily transparent, but also reduce blood flow. The blood perfusion was measured every 3 minutes for 36–66 minutes after diffusion of anhydrous glycerol. Blood flow in small capillaries was found to be reduced significantly within 3–9 minutes. Blood flow in larger blood vessels (i.e., all arteries and veins) decreased over time and some veins had significantly reduced blood flow within 36 minutes. At 24 hours, there was a further reduction in capillary blood perfusion whereas larger blood vessels regained flow compared to an hour after initial application of glycerol.

Conclusion

Blood flow velocity and vessel diameter of the micro‐vasculatures of hamster skin were reduced by the application of 100% anhydrous glycerol. At 24 hours, capillary perfusion remained depressed. Lasers Surg. Med. 41:492–503, 2009. © 2009 Wiley‐Liss, Inc.
Application of a rat‐race coupler in low‐cost load and source pull transistor amplifier design
Authors: Gruszczyński Slawomir , Wincza Krzysztof , Borgosz Jan
Published: August 2009

A method for load and source pull is proposed in which rat‐race couplers with sections of shorted transmission lines are used. It is shown that the connection of a rat‐race coupler with two shorted transmission lines allows for realization of any desired impedance, thus, allowing for effective transistor matching and, therefore, achieving maximum output power. Both theoretical analysis and experimental results are presented showing usefulness of the proposed technique. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2537–2541, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24668
Polymeric ferrite‐loaded antennas for on‐body communications
Authors: Alves T. , Augustine R. , Quéffélec P. , Grzeskowiak M. , Poussot B. , Laheurte J.‐M.
Published: August 2009

Wearable antennas are integral part of body area networks (BANs). Antenna design for BAN applications is a challenging task since the antennas have to be small, efficient, and must not be affected by the wearer's body. This makes isolation of antenna a matter of importance. Ferrites form an opaque media for microwave at the 2.4‐GHz ISM band and hence it could be used for the isolation of antenna from surroundings. Thin polymeric ferrite sheets are used to reduce body influence in BAN perspective. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2530–2533, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24669
Hex‐band antenna for slim handheld device applications
Authors: Ali Shirook M. , Kanj Houssam
Published: August 2009

In this article, we present an approach and design of a small antenna for slim handheld device applications. The basic antenna element is the monopole. The small size and the reduced effective antenna height are achieved from two folding approaches of this monopole. The first is in a three‐dimensional manner, which also results in a broad bandwidth at the desired operating frequencies. The second is achieved by wrapping the antenna around the PCB. This wrapping reduces the physical antenna height to the minimum height required to accommodate the main components of the device without compromising the antenna performance. The proposed antenna is prototyped and modeled, where its performance is examined through simulations and measurements. The antenna supports six frequency bands, GSM 800/900/1800/1900 MHz, UMTS 2100 MHz, and Bluetooth 2400 MHz. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2527–2530, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24670
Dual‐band N‐shaped patch antenna loaded by lumped elements
Authors: Moustafa Asmaa H. , Abdallah Esmat A. , Hashish Essam A.
Published: August 2009

This article presents a dual‐band circular N‐shaped microstrip patch antenna loaded by a shorting pin and lumped R‐C circuit, hence a resonant R‐L‐C circuit is introduced. Loading by shorting pin excites the zero fundamental mode of the circular patch antenna (TM010), and it shifts the first fundamental mode (TM110) to higher one. N‐shaped microstrip patch antenna is used as a modified circular microstrip patch antenna with reduced size. The proposed antenna is designed and fabricated on two‐layered substrate. A comprehensive parametric study has been carried out on values of R and C to optimize the antenna performance. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2534–2537, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24673
Compact angularly stable frequency selective surface using hexagonal fractal configurations
Authors: Wang Wentao T. , Zhang P. F. , Gong S. X. , Lu B. , Ling J. , Wan Tingting T.
Published: August 2009

A compact bandstop frequency selective surface (FSS) using fractal structure is proposed. This flexuous design elongates the cell perimeter of the ring‐shaped FSS, which means the cell size gets smaller at the same resonance frequency. Furthermore, the unit cells adopt regular hexagon and the array employs equilateral triangle form. Because of its symmetric configuration, good frequency stability has been achieved for both horizontal and vertical polarizations at different oblique angles. For the stable bandstop character, this FSS can be used for protecting the staff of S‐band radars against electromagnetic radiation, while the 900/1800/1900 MHz mobile bands and the 5.2/5.8 GHz wireless local area network signals are not affected. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2541–2544, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24676
Dual‐broadband printed monopole antenna with a numeral‐7 slit
Authors: Yang Chao‐Shun , Sze Jia‐Yi , Tu Po‐Jen
Published: August 2009

A 15‐by‐20‐mm2 dual‐broadband printed monopole antenna fed by a coplanar waveguide is presented. With a numeral‐7 slit etched from the rectangular radiating element, the antenna can excite for its lower and upper impedance bands two and one resonant modes, respectively. With a back‐patch appropriately printed on the other side of the substrate, a lower (upper) impedance band with a bandwidth of 39.3% (19.5%) can be obtained. These two impedance bands can cover the frequency bands required by UMTS/IMT‐2000/IEEE802.11a/b/g/WiMAX. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2544–2547, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24677
Precise frequency and bandwidth control of microstrip switchable bandstop filters
Authors: Brito‐Brito Zabdiel , Llamas‐Garro Ignacio , Pradell Lluis
Published: August 2009

In this article two switchable bandstop filters able to switch precisely between two different center frequency and bandwidth states are presented. The filter topologies allow precise control over the design parameters frequency and bandwidth, achieved by choosing adequate resonator sections switched by PIN diodes. Center frequency control was obtained by modifying resonator length. Bandwidth control was achieved by choosing a resonator width and controlling the normalized reactance slope parameter of the decoupling resonators by means of switchable resonator extensions. Both filters were designed to have a 32.5% center frequency tuning range at L band between a low and high filter center frequency. One topology focuses on producing an 8% fractional stopband bandwidth for both filter states. The second filter topology focuses on producing 7 and 9% fractional stopband bandwidths for the low and high filter center frequency states, respectively. Measured results show a very good agreement with the simulations, for the first topology a 32.2% measured center frequency tuning range was obtained with 8.1 and 8.75% fractional stopband bandwidths for the low and high filter center frequency states, respectively. The second filter topology showed a 31.2% measured center frequency tuning range with 6.94 and 9.66% fractional stopband bandwidths for the low and high filter center frequency states, respectively. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2573–2578, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24679
A novel compact bandpass filter using a novel microstrip three‐mode resonator obtaining low loss and sharp attenuation
Authors: He Wenqing , Ma Zhewang , Chen Chun‐Ping , Anada Tetsuo
Published: August 2009

A novel compact ultra‐wideband bandpass filter is designed by using a microstrip three‐mode resonator. The three‐mode resonator is configured by adding a short‐circuited stub and an open stub to a half‐wavelength resonator, and its first three modes are designed to cover a very wide passband. The resonator is fed by parallel‐coupled quarter‐wavelength lines. As a consequence, five reflection zeros are obtained in the passband covering ∼3.4–10.1 GHz. As the filter consists of only one resonator, it is very small and low loss, with measured insertion loss better than 0.6 dB in the passband. The group delay is very flat over the passband, and is about 0.5 ns at the center frequency. Moreover, the filter has multiple transmission zeros near its passband, and exhibits thereby sharp skirt property. The minimum strip‐width and gap‐width in the filter is 0.2 mm and 0.1 mm, respectively, and no complicated backside‐aperture‐fabrication process is required. So the filter can be fabricated easily at low cost. The measured frequency response of the filter agrees favorably with the predicted one, and the Federal Communications Commissions indoor limit is satisfied well. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2547–2551, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24681
A fully integrated CMOS power amplifier with a half‐turn transformer for IEEE 802.11a WLAN applications
Authors: Baek Sang‐Hyun , Hong Songcheol
Published: August 2009

A fully integrated CMOS power amplifier for 5 GHz WLAN applications is implemented using 0.18 μm CMOS technology. An on‐chip transmission‐line transformer is used for output matching and voltage combining. An input balun, interstage matching components, an output transmission‐line transformer, and RF chokes are fully integrated in the amplifier, and thus no external components are required. The power amplifier occupies a total area of 1.7 mm × 1.2 mm. At a 3.3 V supply voltage, the amplifier exhibits a 22.6 dBm output 1 dB compression point, 23.8 dBm saturated output power, and 25 dB power gain. The power added efficiency (PAE) is 21% at maximum, 19% at P1dB. When a 54 Mbps/64 QAM OFDM signal is applied, the PA delivers an average power of 12 dBm at an EVM of −25 dB. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2551–2553, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24683
Discretely tunable fiber ring laser using FBG tunable filter and Mach‐Zehnder interferometer
Authors: Chen Wei , Hua Zhu Ning , Wei Man Jiang , Xiong Shang , Xie Liang
Published: August 2009

A discretely tunable Er‐doped fiber‐ring laser using a fiber Mach‐Zehnder interferometer (MZI) and a tunable fiber Bragg grating (FBG) is proposed. In this scheme, the combination of MZI and FBG acts as a discrete wavelength selector. Analysis of its transmission function shows that discrete wavelength tuning can be realized, and experiments demonstrate 64 single‐mode outputs with a mode spacing of 181.7 pm, and the output power is quite stable in the whole tuning range. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2595–2598, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24690
Triangular planar array of a pyramidal adaptive antenna for satellite communications at 1.7 GHz
Authors: Masa‐Campos J. L. , Montesinos‐Ortego I. , Sierra‐Pérez M.
Published: August 2009

Nowadays, satellite communications are basic for the human lifestyle. In this way, a smart, conformal, and multiarray antenna (GEODA) is being developed in order to receive signals from several satellites simultaneously in the 1.7 GHz working band. An adaptive beam system is able to follow the signals from the satellite constellation. The complex structure of the antenna is based in a 3D composition of planar arrays with triangular shape. These arrays are divided into subarrays of three patches (Cells), composing the single control element for the arrays main beam direction management. Fifteen cells (45 radiating elements) compose each triangular array of the GEODA antenna. In this article, a triangular array prototype is implemented and measured. Likewise, an individual characterization of the array components is presented. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2633–2639, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24692
A compact ultrawideband antenna design based on the current distribution
Authors: Yang Ying‐Ying , Zheng Zhi‐An , Chu Qing‐Xin
Published: August 2009

In this letter, a design of a compact ultrawideband (UWB) antenna is presented, which is based on the current distribution of the previously proposed UWB antenna. The portions with little current distribution are cut from the antenna with less effect on the antenna performance. The modified compact UWB antenna yields an impedance bandwidth of 3.0–50.0 GHz with return loss less than −10 dB. The antenna is successfully simulated, designed, and measured showing extremely broadband matched impedance, stable gain and omni‐directional radiation patterns. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2601–2603, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24695
An efficient evaluation of the Green's functions for periodic structures in multilayered media
Authors: Zhuang W. , Chen R. S. , Ding D. Z.
Published: August 2009

An efficient scheme is presented to calculate the periodic structure in planar multilayered media. The slowly converging series for the periodic Green's function is accelerated using the Ewald's method combined with Shank transformation and the computational time is significantly reduced compared with the direct spectral summation. Numerical examples are given to demonstrate the efficiency of the proposed method. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2639–2643, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24696
Compact circularly polarized omnidirectional microstrip antenna
Authors: An Jian , Wang Guang‐Ming , Zhang Chen‐Xin , Zeng Hui‐Yong
Published: August 2009

A new type of circularly polarized omnidirectional microstrip antenna employing zeroth‐order resonator loaded with stubs along the ground perimeter is presented. The proposed antenna has the conceptual configuration of the horizontal magnetic and electric loop currents which act as the electric and magnetic monopole antennas, respectively. By adjusting the relevant dimensions of the loaded stubs, circularly polarized omnidirectional operation can be realized. The proposed antenna operates at 1.55 GHz and provides a 10 dB input return loss bandwidth of 1.3%. The whole dimensions of the proposed antenna are about λ/6×λ/6×λ/96 in terms of vacuum wavelength. The simulated and measured radiation patterns show the proposed antenna radiates electromagnetic wave omnidirectionally. The simulated axial ratio of the proposed antenna indicates it has good circular polarization performance. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2643–2646, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24697
Performance and capacity analysis of 60 GHz WPAN channel
Authors: Geng Suiyan
Published: August 2009

In this work, the performance and capacity of both 60 GHz ultrawide‐band (UWB) and multiple‐in multiple‐out (MIMO) channels are analyzed based on experimental channel models and specifications for millimeter‐wave wireless personal area networks (WPANs). In the analysis of 60 GHz UWB channel, the radio link budget is estimated by applying two experimental channel models where blocking effect is considered and fading margin (FM) is modeled as a function of channel bandwidth. Results show that high gain antennas are required in 60 GHz UWB channel. The high gain antenna systems suffer from poor flexibility and the directional signals can be easily blocked in multipath indoor environments. This indicates that gigabit communications is quite difficult in 60 GHz UWB channel. To overcome this problem, adaptive antenna arrays (or MIMO systems) are required as they can search and direct the available signals to improve radio link budget. The 60‐GHz MIMO channel capacity is analyzed by modeling FM as a function of number of antenna elements. The proposed NLOS channel model is employed in rich scattering or multipath environments for achieving high capacity in MIMO channel. Tests were also performed for determining gigabit data rate, operation range and configuration in the 60‐GHz MIMO case. The goal of this study is to provide useful information for the design of future 60 GHz WPAN systems. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2671–2675, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24698
A single‐feed circularly‐polarized patch antenna for reduced surface wave applications
Authors: Al‐Ajmi Ayed R. , Mahmoud Samir F.
Published: August 2009

A circularly polarized (CP) microstrip patch antenna design with single probe‐feed is proposed for reduced surface waves applications. The circular polarization is achieved by embedding a narrow slot at the center of a circular patch with an intersecting angle of 45 degrees relative to the feed position. Simulation results using the IE3D software facility have shown the capability of achieving circular polarization with high polarization purity while maintaining the reduction of surface waves and lateral waves. The simplicity of the design, together with the circular polarization characteristics and surface wave reduction indicate that this new antenna design is a promising candidate for applications including large patch antenna arrays and high precision GPS receiving antennas. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2675–2679, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24699
To compact ring branch‐line coupler using nonuniform transmission line
Authors: Hosseini F. , Hosseini M. Khalaj‐Amir , Yazdany M.
Published: August 2009

A compact ring Branch‐Line Coupler (BLC) with size reduction of about 50%(in circuit area) of conventional BLCs at frequency 2 GHz is introduced. The coupler is designed by using nonuniform transmission lines (NTL) instead of Uniform Transmission Lines in each arm. The normalized width w (z)/h function of the NTLs is expanded in a truncated Fourier series. The reduced size couplers are potential building blocks for the growing wireless communication markets. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2679–2682, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24703
Multi split‐step unconditionally stable finite difference time domain methods
Authors: Kusaf Mehmet , Oztoprak Abdullah Y.
Published: August 2009

New unconditionally stable split‐step FDTD methods with 6 and 8 split‐steps are introduced. A new definition of the stability factor is used for fair comparison of multi split‐step methods, which takes into account the number of split‐steps as well. When different methods are compared, on equal time basis using this definition, it is found that the new methods have the best dispersion error performance. Dispersion performances of some of the previously reported “improved” multi split‐step FDTD methods do not seem to be as good as claimed. It has also been shown that for each space step value, the new methods have zero anisotropic error at certain large stability factor (time step) values. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2646–2649, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24704
A 57‐GHz CMOS VCO with 185.3% tuning‐range enhancement using tunable LC source‐degeneration
Authors: Tsou Chuan‐Wei , Chen Chi‐Chen , Lin Yo‐Sheng
Published: August 2009

A 57‐GHz CMOS voltage‐controlled oscillator (VCO) using tunable LC source‐degeneration for operation frequency and tuning‐range enhancement is demonstrated. The tunable LC source‐degeneration is made by adding two tunable LC tanks, where varactors are used as the needed capacitors, to the source terminals of the cross‐coupled transistor pair of the VCO. Compared with the traditional cross‐coupled transistor pair, the proposed one significantly decreases the equivalent parallel capacitance (CEQ). This in turn results in the increase of both the operation frequency and the tuning range of the VCO. The measurement result shows the tunable LC source‐degeneration achieved a 185.3% enhancement [from 1.36 GHz (53.36–54.72 GHz) to 3.88 GHz (53.36–57.24 GHz)] in tuning range by tuning the varactors of the proposed cross‐coupled transistor pair. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2682–2685, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24706
A low‐power CMOS receiver for wireless sensor networks
Authors: Chen Yen‐Jen , Lin Yu‐Tso , Liao Fang‐Ren , Chen Hsiao‐Chin , Lu Shey‐Shi
Published: August 2009

A monolithic on‐off keying receiver is presented for wireless sensor network applications. By employing the self‐mixing technique, the demodulator is constructed from a voltage multiplier instead of a rectifier in this work. The proposed receiver can achieve a data rate upto 1 Mb/s at a power consumption of 15.4 mW while occupying a die area of only 0.25 mm2. For a bit rate of 5 kb/s and a pseudo‐random sequence of 29 − 1, the receiver exhibits a sensitivity of −60 dBm at 433 MHz. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2618–2620, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24707
Design of a new wideband low‐profile conical antenna
Authors: Ma Jie , Yin Y.‐Z. , Zhou S.‐G. , Zhao L.‐Y.
Published: August 2009

A very low‐profile conical antenna with a simple structure and wideband characteristic is proposed in this article. The antenna structure consists of a monoconical conducting body, a parasitic ring shorted to a finite‐sized ground plate to achieve low‐profile characteristic (Nakano et al., IEEE Trans Antennas Propag 56 (2008) 1187‐1192), and a sleeve attached to the ground for yielding an extreme wide VSWR bandwidth. The experimental result shows that the proposed antenna, with a height of only 0.0625 wavelength at the lower edge frequency of the bandwidth, exhibits a 7.9:1 impedance bandwidth from 747 to 5900 MHz with VSWR below 2.5. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2620–2623, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24713
Microwave circuit miniaturization with complementary spiral resonators: Application to high‐pass filters and dual‐band components
Authors: Selga Jordi , Sisó Gerard , Gil Marta , Bonache Jordi , Martín Ferran
Published: August 2009

In this contribution, it is shown that complementary spiral resonators (CSRs) are useful particles for the miniaturization of planar microwave components based on metamaterial concepts. Specifically, we will focus on two different applications: (i) the design of high pass filters based on balanced composite right/left handed microstrip lines and (ii) the design of dual band impedance inverters, which can be applied to many different devices such as couplers and power dividers, among others. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2741–2745, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24715
Circular dielectric cantor fibers
Authors: Chiadini F. , Fiumara V. , Gallina I. , Scaglione A.
Published: August 2009

Cantor fibers having a multilayered cladding structured according to the Cantor fractal scheme are introduced. In each layer the radial field distribution is determined solving a boundary value problem. The mode propagation constant is calculated minimizing the outgoing power flux. Such fibers suffer from low losses even for few cladding layers. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2726–2728, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24716
Plasmonic and non‐plasmonic layered structures for cloaking applications at visible frequencies
Authors: Tricarico Simone , Bilotti Filiberto , Vegni Lucio
Published: August 2009

In this letter, we present the theoretical analysis and the design principles of electromagnetic cloaking devices working at optical frequencies. The cloaking approach is based on the scattering cancellation principle. The robustness of the cloaking devices is also discussed, proposing a proper figure of merit and validating the design through a set of full‐wave numerical simulations. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2713–2717, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24718
Guest editorial: Special issue on metamaterials and special materials for electromagnetic applications and telecommunications
Authors: Andreone Antonello , Galdi Vincenzo
Published: August 2009

© 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2694–2695, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24722
Light confinement in coherently driven defect states in solids
Authors: Wu Jin‐Hui , Artoni Maurizio , La Rocca Giuseppe C.
Published: August 2009

Inhomogeneously broadened optical transitions in nitrogen‐vacancy color centers in diamond and Pr3+ doped yttrium orthosilicate may be employed to attain all‐optically controlled Bragg structures with photonic band‐gaps of high reflectivities and large bandwidths. Such a control mechanism is valuable for improving performance and scalability of solid quantum memory devices. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2722–2726, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24723
Slow microwave waveguide made of negative permeability metamaterials
Authors: Lu Wentao T. , Savo Savatore , Casse B. Didier F. , Sridhar Srinivas
Published: August 2009

The framework for designing a slow light waveguide structure which operates in the GHz and up to THz frequencies is outlined. The design for the structure consists of a dielectric core layer cladded with negative permeability metamaterials. The parameter space for the metamaterial has been identified for the waveguide to stop light and the negative permeability is achieved by split‐ring resonator (SRR) metallic elements. A prototype structure operating at 8.5 GHz is proposed. Numerical simulations of electromagnetic waves interacting with SRRs have been performed to extract scattering parameters and a parameter retrieval method has been used to verify the designed window for negative permeability. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2705–2709, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24727
Metamaterial applications in RFID
Authors: Toscano A. , Vegni L.
Published: August 2009

In this article, we discuss various requirements of antenna design for passive radio frequency identification (RFID) tags, we outline a generic design process and show how RFID tags loaded with a metamaterial slab are able to increase the read range and to decouple the tag with the tagged objects. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2745–2748, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24728
Efficient numerical analysis of large planar high impedance surface by the synthetic function expansion technique
Authors: Matekovits Ladislau , Vecchi Giuseppe , Bercigli Mirko , Bandinelli Mauro
Published: August 2009

Application is presented of the Synthetic Function eXpansion (SFX) method to the accurate analysis of devices that incorporate microstrip‐technology electromagnetic band‐gap structures of large but finite size. The strong reduction of the dimension of the system matrix achieved employing the SFX technique reduces the solution time and the memory occupation, making it possible to analyze large structures on standard computational hardware. Experimental verification confirms the validity of the approach. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2763–2769, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24729
Modeling of diamond field‐effect transistors for RF IC development
Authors: Pasciuto B. , Ciccognani W. , Limiti E. , Serino A. , Calvani P. , Corsaro A. , Conte G. , Rossi M. C.
Published: August 2009

On the basis of RF characteristics and measured small‐signal parameters, an equivalent circuit model was formulated and characterized for metal‐semiconductor field effect transistors based on H‐terminated polycrystalline diamond. Starting from on‐wafer measurements, a bias‐dependent transistor behavior representation was fully determined. Such an equivalent circuit model is the first important step to realize an RF IC based on diamond. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2783–2786, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24734
Unidimensional EBG cavities as superstrates of a patch antenna
Authors: Frezza Fabrizio , Pajewski Lara , Ponti Cristina , Schettini Giuseppe
Published: August 2009

In this article, a design of both high‐selectivity and compact one‐dimensional electromagnetic band‐gap (1D‐EBG) cavities is presented, considering the effect of the layers' thickness and of the permittivity of the constitutive materials. Compact and high‐selectivity cavities are proposed, to be employed as spatial filters. In particular, EBG antennas can be obtained when the ground plane of a patch antenna is placed in the symmetry plane of these cavities. An effect of enlargement of the equivalent‐aperture area is determined, resulting in high‐gain radiation. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2769–2774, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24737
Scattering analysis of frequency selective shields for electromagnetic indoor isolation
Authors: Stefanelli Riccardo , Trinchero Daniele
Published: August 2009

The article illustrates numerical and experimental analyses of microwave spatial filters, designed to reduce human exposure to electromagnetic fields in living environments. The identified technological solution makes use of periodic structures with frequency selective behavior. To demonstrate its applicability, some prototypes were designed, manufactured, and measured, thanks to the identification of a dedicated setup. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2758–2762, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24739
Berkson's bias and the mood dimensions of bipolar disorder
Authors: Regeer E.J. , Krabbendam L. , De Graaf R. , Ten Have M. , Nolen W.A. , Van Os J.
Published: August 2009

In this paper we examined whether manic and depressive dimensions independently contribute to mental health service use and determined the degree of comorbidity between manic and depressive dimensions in individuals with and without mental health service use. If both depressive and manic episodes independently influence help‐seeking behaviour, a higher level of comorbidity between these dimensions would be found in clinical as compared to non‐clinical samples (i.e. Berkson's Bias). Data were derived from the Netherlands Mental Health Survey and Incidence Study (NEMESIS), a prospective epidemiological survey in a representative sample of the Dutch population (N = 7076). Dimensions of depression and mania and mental health service use (MHSU) were assessed with the Composite International Diagnostic Interview (CIDI) at baseline, and prospectively one and three years later. Logistic regression was used to test whether depressive and manic dimensions both had independent effects on mental health service use. The degree of mania‐comorbidity given the presence of depressive dimension was assessed as a function of MHSU, both retrospectively and prospectively. Manic and depressive dimensions contributed independently to mental health service use. Mania‐comorbidity given the presence of depressive dimension was significantly higher in individuals with mental health service use than in those without, both retrospectively (16.7% versus 7.1%, p = 0.000) and prospectively (10.8% versus 6.6%, p = 0.017). We conclude that the bipolar phenotype consists of manic and depressive dimensions that may be much more loosely associated than (Berkson) biased clinical observations suggest. A dimension‐specific approach may be more productive in clarifying the aetiology of mood dysregulation. Copyright © 2009 John Wiley & Sons, Ltd.
Facile construction of multivalent targeted drug delivery system from Boltorn® series hyperbranched aliphatic polyester and folic acid
Authors: Wang Jinrong , Xu Tongwen
Published: August 2009

The conjugation of PAMAM dendrimer and folic acid is a well‐studied multivalent targeted drug delivery system, but it is expensive and difficult to be synthesized. To construct an inexpensive and well‐defined multivalent targeted drug delivery system, a cheap carrier — Boltorn® series hyperbranched aliphatic polyester — was proposed as the nanodevice to carry fluorescein, folic acid, and methotrexate. The construction follows a facile route: (1) synthesizing the carrier — a hybrid hyperbranched polymer with acyclic hydroxyls and cyclic carbonate, (2) linking fluorescein to the hyperbranched polymer via the acyclic hydroxyls, (3) opening the ring of the cyclic carbonate with the amino group of folic acid, and (4) attaching the drug methotrexate to the resulting hydroxyls by ring‐opening reaction. In this route, the peripheral hydroxyls of the hyperbranched polymer are divided into two groups and reacted with three reagents in sequence to form the desired multivalent targeted drug delivery system. Copyright © 2009 John Wiley & Sons, Ltd.
Flexible modeling of the cumulative effects of time‐dependent exposures on the hazard
Authors: Sylvestre Marie‐Pierre , Abrahamowicz Michal
Published: August 2009

Many epidemiological studies assess the effects of time‐dependent exposures, where both the exposure status and its intensity vary over time. One example that attracts public attention concerns pharmacoepidemiological studies of the adverse effects of medications. The analysis of such studies poses challenges for modeling the impact of complex time‐dependent drug exposure, especially given the uncertainty about the way effects cumulate over time and about the etiological relevance of doses taken in different time periods. We present a flexible method for modeling cumulative effects of time‐varying exposures, weighted by recency, represented by time‐dependent covariates in the Cox proportional hazards model. The function that assigns weights to doses taken in the past is estimated using cubic regression splines. We validated the method in simulations and applied it to re‐assess the association between exposure to a psychotropic drug and fall‐related injuries in the elderly. Copyright © 2009 John Wiley & Sons, Ltd.
Using Image Analysis to Identify Acetylated Distarch Adipate in a Mixture
Authors: Šárka Evžen , Bubník Zdeněk
Published: August 2009

The NIS‐Elements image analysis system, together with microscopic observation, was used to measure the particle size of acetylated distarch adipate (ADA) in three suspensions; a commercial mixture containing other additives and two pure commercial ADA starches. From these data, the particle size distribution was calculated. The starch in the mixture was identified as wheat ADA, and the normality of the size distribution for volume fraction tested. Image analysis can be recommended as a simple and rapid method for identifying the origin of modified starches in commercial powder mixtures.
Validation and modification of the Blade Element Momentum theory based on comparisons with actuator disc simulations
Authors: Madsen Helge Aa. , Bak Christian , Døssing Mads , Mikkelsen Robert , Øye Stig
Published: August 2009

A comprehensive investigation of the Blade Element Momentum (BEM) model using detailed numerical simulations with an axis symmetric actuator disc (AD) model has been carried out. The present implementation of the BEM model is in a version where exactly the same input in the form of non‐dimensional axial and tangential load coefficients can be used for the BEM model as for the numerical AD model. At a rotor disc loading corresponding to maximum power coefficient, we found close correlation between the AD and BEM model as concerns the integral value of the power coefficient. However, locally along the blade radius, we found considerable deviations with the general tendency, that the BEM model underestimates the power coefficient on the inboard part of the rotor and overestimates the coefficient on the outboard part. A closer investigation of the deviations showed that underestimation of the power coefficient on the inboard part could be ascribed to the pressure variation in the rotating wake not taken into account in the BEM model. We further found that the overestimation of the power coefficient on the outboard part of the rotor is due to the expansion of the flow causing a non‐uniform induction although the loading is uniform. Based on the findings we derived two small engineering sub‐models to be included in the BEM model to account for the physical mechanisms causing the deviations. Finally, the influence of using the corrected BEM model, BEMcor on two rotor designs is presented. Copyright © 2009 John Wiley & Sons, Ltd.