bluuebunny/crossref_metadata_2025 huggingface dataset:
Planar branched monopole antenna for UWB applications
Authors: Jacob K. Francis , Suma M. N. , Raj Rohith K. , Joseph Manoj , Mohanan P.
Published: November 2006

Development of a compact microstrip‐fed, branched monopole antenna for ultra wide band (UWB) applications is presented. By suitably embedding branches on the top edge of the strip monopole, an UWB response can be easily achieved by merging different resonances. The simulated and experimental results demonstrate that the proposed antenna achieves more than 3:1 impedance bandwidth for 2:1 VSWR criteria. The antenna exhibits nearly omni directional radiation characteristics and moderate gain in the entire band. The proposed antenna is printed on a FR4 substrate of εr = 4.4 and thickness h = 1.6 mm and having an overall dimension of 65 × 35 mm2 including the ground plane. The parameters that affect the performance of the antenna are presented and discussed. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 45–47, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22045
Study of the Bluetooth headset antenna with the user's head
Authors: Wong Kin‐Lu , Hsu Ming‐Ren , Li Wei‐Yu , Su Saou‐Wen , Chen Austin
Published: November 2006

A promising planar inverted‐F metal‐strip antenna suitable for Bluetooth headset application is studied. The antenna has a low‐profile appearance and can be embedded inside the housing of the Bluetooth headset to operate as an internal antenna. The antenna is to be mounted along the side edge of the system circuit board of the headset, almost not occupying the valuable board space. Results have indicated that, when the antenna is mounted at either end of the side edge, a large bandwidth (>250 MHz) centered at about 2442 MHz can be achieved, making the antenna easily cover the Bluetooth operation in the 2400–2484 MHz band. Performances of the studied antenna attached to the user's head are also studied. Large distortion in the antenna's radiation pattern is observed. However, the antenna's radiation efficiency is still larger than about 70% over the operating band, which is acceptable for practical applications. Details of the obtained experimental and simulation results are presented and discussed. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 19–23, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22047
Transmission peak at low frequencies by a fractal distribution of metamaterials layers in free space
Authors: Saleh A. S. , Raveu N.
Published: November 2006

A periodic distribution of metamaterials layers in free space generates wide forbidden bands. This work investigates the Cantor bar distribution of metamaterials slabs in free space. This distribution provides narrow transmission peaks in the forbidden bands. A design of narrow bandpass filter with a signification gain of dimension is proposed. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 105–109, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22048
Cladding mode coupling suppression in hole‐assisted fiber BRAGG gratings
Authors: Han Young‐Geun , Lee Young Jun , Kim Gil Hwan , Cho Hung Su , Lee Ju Han , Lee Sang Bae
Published: November 2006

We experimentally investigate the cladding mode coupling loss of fiber Bragg gratings written in hole‐assisted fibers. The cladding mode coupling loss is remarkably suppressed due to air holes inside of the silica cladding. The reduction of cladding mode coupling loss of less than ∼0.33 dB is obtained. The wavelengths spacing between the main peak due to the core mode coupling and the first side peak due to the first order cladding mode coupling is changed by the increase of the air holes size since the effective index of cladding mode is reduced by the air hole size within the fiber. The variation of the wavelength spacing is ranged from 2.0 to 2.28 nm. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 74–74, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22050
A coplanar waveguide‐fed folded‐slot monopole antenna for 5.8 GHz radio frequency identification application
Authors: Liu Wen‐Chung
Published: November 2006

Design of a simple coplanar waveguide (CPW)‐fed patch antenna for radio frequency identification (RFID) application is presented. The radiation mechanism of such an antenna has been investigated, based on a moment‐method numerical analysis and experimental measurement. The antenna with a symmetrical folded slot to become a U‐shaped monopole can excite 5.8 GHz resonance mode with impedance bandwidth of 490 MHz, average antenna gain of ≥4.1 dBi, and monopole‐like radiation patterns but has a compact antenna size. These properties make the antenna suitable for use in RFID tags. In addition, an equivalent circuit model for such kind of antenna is also presented to account for its radiation characteristics. Good agreement between the simulated and modelled results has been obtained. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 71–74, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22051
Millimeter wave bandpass filter using three‐line microstrip structures
Authors: Zhang Zan , Gu Jian‐Zhong , Wang Chuang , Sun Xiao‐Wei
Published: November 2006

This paper presents a novel Ka‐band millimeter bandpass filter using three‐line microstrip structures. A network analysis of a three‐line unit is described, and the scattering parameters of the unit cell are derived. A demonstration three‐line bandpass filter and a traditional two‐line one, centered at 35 GHz, are designed, fabricated, and measured. The simulation and measured results are with good agreements. When compared with the conventional parallel coupled line microstrip structures, the new structure bandpass filter owns its practical advantages; it has improved stop band rejections, low insertion loss in pass band, reduced area of circuit layout, and released line spacing limitation for the first and last coupling units of filters. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 40–42, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22053
Short helical antenna with extremely small pitch angle
Authors: Wu Ze‐Hai , Yung Edward K. N.
Published: November 2006

A 2‐turn helical antenna with small pitch angle between 0.6° and 3° has been studied as a radiation element of circular polarization waves in this article. The antenna with pitch angle 2° exhibits a 3‐dB axial ratio bandwidth of 9.8%, and the optimal axial ratio of 0.1 dB. When the pitch angle decreases to 0.6°, the 3‐dB axial ratio bandwidth and the best axial ratio are 5% and 0.15 dB, respectively. Variation of on‐axis axial ratio as a function of the straight wire height h has been computed, and the current along the helix is also given. Experimental verification of the antenna performance is presented. The antenna with low profile and high polarization purity characteristics is suitable for application of array antenna. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 17–19, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22054
Coplanar to microstrip transitions for on‐wafer measurements
Authors: Wang Yi , Lancaster Michael J.
Published: November 2006

Two types of via‐free coplanar line to microstrip transitions are designed and tested for on‐wafer measurements. The transitions are designed to fit coplanar ground‐signal‐ground probes. They are taper transitions with capacitive ground patches and radial stub transitions. Both structures are easy implemented and exhibit wideband transmission. The performance of the optimized taper transition is among the best demonstrated in terms of a return loss of less than −20 dB from 5 to 15.5 GHz; this is even superior to the radial stub designs. Design information is given, which is based on full‐wave simulations for the taper transition, and analytical formulations for the radial stub. The increasing bandwidth with increased angle of the radial stub is observed. The transition structures and design guidelines addressed can be used for on‐wafer measurements of a wide range of microstrip circuits. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 100–103, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22056
Circuit model and near‐field behavior of a novel patch antenna for WWLAN applications
Authors: Caratelli Diego , Cicchetti Renato , Bit‐Babik Giorgi , Faraone Antonio
Published: November 2006

The circuit model and the near‐field behavior of a novel wide‐band E‐shaped microstrip patch antenna suitable for wireless communication devices are presented. A suitable locally conformal FDTD numerical procedure is employed to analyze the electromagnetic field excited by the radiator, and to derive a frequency‐independent antenna equivalent circuit. Numerical results concerning the antenna parameters are in good agreement with experimental measurements. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 97–100, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22057
Multiband internal antenna with independently adjusted resonance frequencies
Authors: Kim Jeongpyo , Seong Wonmo , Choi Jaehoon
Published: November 2006

A multiband internal antenna capable of independently adjusting resonance frequencies is presented. The designed antenna consists of two radiators and has three resonance frequencies including the cellular, Korean personal communication system (K‐PCS), and satellite digital multimedia broadcasting (S‐DMB) band. The first and third resonance frequencies are fixed by the Radiator 1 of the antenna and the second is controlled by the Radiator 2. Three resonance frequencies of the designed antenna can be independently adjusted by controlling the length of individual radiator. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 65–68, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22059
A miniaturized phased array aperture antenna based on bulk ferroelectric material
Authors: Peng Liang , Ran Lixin , Zou Yingyin K. , Kong J. A.
Published: November 2006

In this article, we proposed a novel miniaturized phased array aperture antenna using a voltage‐controllable ferroelectric material with high dielectric constant. This antenna system combines the phase shifters and the radiating elements in a single structure, that could significantly simplify the complexity and the cost of the conventional phased array antenna systems. Simulation results on such structure are given, which agrees well with the theoretical analysis. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 37–40, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22060
Minimized closed‐loop high‐selectivity dual‐band filters using trisection stepped‐impedance resonators
Authors: Huang Tsung‐Hui , Chen Han‐Jan , Chang Chin‐Sheng , Chen Lih‐Shan , Horng Jui‐Hong , Wang Yeong‐Her , Houng Mau‐Phon
Published: November 2006

In this letter, a minimized closed‐loop dual‐band filters using trisection stepped‐impedance resonators (SIR) structure is presented. The closed‐loop trisection SIR with dual‐band frequency response are designed, and to establish appropriate couplings in the structure. Moreover, the proposed filter also provides the size reduction of the maximum 98% against the other dual‐band filter. The total size of the filter is less than 14 mm × 14 mm based on RO3003 substrate. In addition, the proposed filter can be implemented by using a printed circuit board (PCB) technology to achieve low‐cost, easily integrated design and fabrication. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 219–221, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22062
An experimental study on electromagnetic properties of random fiber composite materials
Authors: Xu X. , Qing A. , Gan Y. B. , Feng Y. P.
Published: November 2006

Extensive experimental study on composite slabs with fiber inclusions has been carried out. Attention is focused on the key factors affecting the effective properties of fiber composite slabs, i.e., concentration, length, and conductivity of fiber inclusions and electrical contact between fibers. Two kinds of fibers with different conductivity, namely, Cu and C, are considered. Samples with fiber inclusions of different concentration and length are fabricated. Transmission coefficients of these samples were measured. The measured results agree reasonably well with simulation results obtained by using a previously proposed method. The effect of the key factors has been identified. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 185–190, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22064
Microstrip antenna miniaturization using partial dielectric material filling
Authors: Luukkonen Olli , Ikonen Pekka , Tretyakov Sergei
Published: November 2006

In this paper we study microstrip antenna miniaturization using partial filling of the antenna volume with dielectric materials. An analytical expression is derived for the quality factor of an antenna loaded with a combination of two different materials. This expression can be used to optimize the filling pattern for the design that most efficiently retains the impedance bandwidth after size reduction. Qualitative design rules are given, and a miniaturization example is provided where the antenna performance is compared for different filling patterns. Results given by the analytical model are verified with numerical simulations and experiments. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 155–159, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22066
Ultrawideband planar microstrip‐fed monopole antenna
Authors: Tseng Ching‐Fang , Huang Cheng‐Liang
Published: November 2006

The microsrip‐fed ultrawideband (UWB) monopole antenna is studied. The design is demonstrated assuming FR4 substrate with a relative dielectric constant of 4.4 and thickness of 1.6 mm. The presented results show that the proposed antenna of 43 mm ×50 mm dimensions has a bandwidth from 2.85 GHz to more than 15 GHz. The bandwidth covered 3.1–10.6 GHz, which has approved by the Federal Communications Commission as a commercial UWB band. Satisfactory performance was obtained using FR4 substrate, allowing low cost of production. Moreover, the antenna features near omnidirectional characteristics and good radiation efficiency. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 183–185, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22069
Low‐loss triangular‐patch dual‐mode bandpass filter with slotted input/output
Authors: Liu Haiwen , Cheng Zhiqun , Sun Lingling
Published: November 2006

Without any perturbations on the surface of the patch resonator or orthogonal feed lines, a novel microstrip dual‐mode triangular‐patch bandpass filter with slotted I/O is introduced in this letter. The degenerate modes are excited by the use of the slotted I/O. Also, the coupling characteristics of two degenerate modes are studied with respect to main design parameters. A dual‐mode filter with 0.8 dB insertion loss in the passband was designed and fabricated. Measurement verify the validity of the proposed design method. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 147–149, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22072
Multiple sweep method of moments analysis of electromagnetic scattering from 3D targets on ocean‐like rough surfaces
Authors: Çolak D. , Burkholder R. J. , Newman E. H.
Published: November 2006

This paper presents the multiple sweep method of moments (MSMM) analysis of electromagnetic (EM) scattering from three dimensional (3D) targets on ocean‐like rough surfaces. The MSMM is a recursive method for solving the large matrix equations which arise in the method of moments (MoM) analysis of electrically large bodies. In the MSMM, the body is split into P sections and the currents on these sections are found in a sequential downrange‐uprange fashion. The first sweep includes the dominant scattering mechanisms and each subsequent sweep includes higher order mechanisms. The results obtained from this study demonstrate that the MSMM is a very reliable and efficient tool for the analysis of this class of problems. The numerical results yield insight into electromagnetic scattering mechanisms associated with a 3D target on a rough surface, and provide accurate and robust reference solutions for more approximate techniques which can handle larger geometries more efficiently. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 241–247, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22074
A novel programmable predistortion circuit for broadband InGaP/GaAs HBT power amplifier
Authors: Gao Huai , Wang Rong , Zhang Haitao , Xue Hongxi , Li G. P.
Published: November 2006

A novel programmable MMIC predistortion circuit as an input stage of a broadband power amplifier (PA) is proposed and designed. By varying its reference voltage, one can adjust the magnitude of gain expansion and negative phase deviation to compensate the typical nonlinearities of the following stages in a PA, as well as temperature and fabrication variations. A gain expansion of 4–5 dB and a phase improvement of 5–6° are achieved in simulation. The measurement results show that P1dBis improved by 3 dB and adjacent channel power rejection ratio (ACPR) by 5 dBc at 27 dBm output power. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 141–143, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22080
A novel multiband dipole antenna with a microstrip loop feed
Authors: Liao Wen‐Jiao , Lu Yu‐Cheng , Chou Hsi‐Tseng
Published: November 2006

A novel microstrip antenna applicable for multiband use is proposed in this work. The design was evolved from a conventional parallel stripline dipole with modifications in the dipole geometry and feeding structure. Those measures help introduce new resonant modes and increase bandwidths in the radiation spectrum. Fundamental antenna parameters including reflection coefficients, antenna gains, radiation patterns, and efficiency are measured. The results suggest that the proposed dipole provides roughly omni directional patterns at 1.8 to 2.4, 3.6, and 5.8 GHz bands with ∼0 dBi gain on the H‐plane of the dipole. Such a planar antenna is of low cost and can be used on personal portable communication devices such as the smart phones to fulfill the multiband need of integrated mobile, Bluetooth, Wi‐Fi, and WiMAX systems. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 237–241, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22081
Waveguide miniaturization with Sr(ZnTi)Fe10O19 hexaferrite metamaterial
Authors: Liu Ji‐Chyun , Liu Chin‐Yen , Hong Yaw‐Shun , Wu Ching‐Yang , Lou Der‐Chyuan
Published: November 2006

An X‐band rectangular waveguide partially filled with ferrite metamaterial exhibiting the transversal negative permeability is investigated in this article. Several kinds of the miniaturized waveguide loaded with the novel Sr(ZnTi)Fe10O19 ferrite in 7 GHz frequency band have been measured. The results reveal backward‐wave pass‐band located below the cutoff frequency. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 201–203, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22083
Directivity enhancement of circular polarized patch antenna using ring‐shaped frequency selective surface superstrate
Authors: Lee Dong Hyun , Lee Young Ju , Yeo Junho , Mittra Raj , Park Wee Sang
Published: November 2006

In this letter, a ring‐shaped frequency selective surface (FSS) superstrate is designed to enhance the directivity of a circularly polarized patch antenna by reducing the sidelobe levels. Based on the unit cell simulation, several important parameters that characterize the ring‐shaped FSS superstrate are investigated, and the design procedure of the FSS superstrate is described. The FSS antenna composite is fabricated, and the maximum directivity is 18.98 dBi, while the sidelobe level is −18 dB. Furthermore, the antenna composite maintains its circular polarization characteristic quite well. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 199–201, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22084
Compact dual‐band bandpass filter with enhanced feed coupling structures
Authors: Weng Min‐Hang , Huang Chun‐Yueh , Wu Hung‐Wei , Shu Kevin , Su Yan‐Kuin
Published: November 2006

This letter proposes a novel compact dual‐band bandpass filter (BPF) using the meandering open‐loop resonators (MOLRs) and with enhanced feed coupling structures (EFCS). It is shown that the designed dual band BPF has a small area in comparison of previous works. The high selectivity of the designed BPF can be obtained due to the appearance of transmission zeros in two passband edges by using the EFCS in the proposed BPF. The full‐wave simulator IE3D is used to design the MOLRs and to calculate the coupling coefficients of the basic coupling structures. Good agreement with response of electromagnetic simulation and measurement is compared. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 171–173, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22085
Substrate integrated waveguide horn antenna with dielectric lens
Authors: Che Wenquan , Fu Bing , Yao Ping , Chow Y. L.
Published: November 2006

A novel compact H‐plane horn antenna constructed is proposed for substrate integrated rectangular waveguide with ξr = 10.2. It has a dielectric arc lens for better directivity and a simple microstrip transition as feed. The horn, the lens, and the transition share the same substrate. The measured gain of this antenna is about 9 dB; the bandwidth, at 10 dB return loss, is over 12%, and the antenna size is 39.175 × 14 × 2 mm3. The frequency band is 25.5–28.5 GHz. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 168–178, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22086
Photonic microphone based on a dual‐core multimode fiber head combined with a micromirror diaphragm
Authors: Song Ju‐Han , Lee Sang‐Shin
Published: November 2006

A compact photonic microphone has been proposed and realized, incorporating a dual‐core multimode fiber (MMF) block combined with a reflective micromirror‐based diaphragm. The fiber block, where two MMFs are aligned and tilted toward each other with an angle, played a role as an optical head used to transfer light to and from the diaphragm. And the membrane‐type micromirror made of a silicon film coated with gold films was implemented to be suspended via a thin bar connected to a silicon frame, thereby enabling dynamic displacement induced by applied acoustic waves. For the demonstrated microphone, its static characteristics were first examined to find out the operating point defined as the optimum distance between the optical head and the diaphragm. Its measured frequency response was examined to exhibit an operation bandwidth of 3 kHz with the variation of ∼5 dB. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 135–137, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22088
Application of the Foldy–Lax multiple scattering method to the analysis of vias in ball grid arrays and interior layers of printed circuit boards
Authors: Ong C.‐J. , Miller D. , Tsang L. , Wu B. , Huang C.‐C.
Published: November 2006

The authors applied the method of Foldy–Lax multiple scattering equations to multiple vias in ball grid arrays and the interior layers of printed circuit boards. The method gives the scattering parameters of the array. The results are verified with Ansoft's HFSS with very little difference between the Foldy–Lax approach and the HFSS results. The CPU required for the method is only a small fraction of the time that HFSS requires. For a 16 × 16 array of vias, the method calculates all the S‐parameters of the 512 ports in 4 min for 10 frequencies on a Pentium 3.2 GHz PC. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 225–231, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22091
Application of high impedance electromagnetic surface to archimedean planner spiral antenna
Authors: Wang Chao , Yan Dun‐bao , Yuan Nai‐chang
Published: November 2006

A new type of artifical metallic electromagnetic structure, high impedance electromagnetic surface (HIS), has been developed that is characterized by having high surface impedance. In this paper, the HIS is used as the antenna ground plane to suppress the propagation of surface waves and improve performance of Archimedean planner spiral antenna. Measured results reveal that the HIS can remarkably increase the gain of main lobe, decrease the back lobe, and reduce the mutual coupling between receiving antenna and transmitting antenna. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 129–131, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22097
A candidate precursor to serous carcinoma that originates in the distal fallopian tube
Authors: Lee Y , Miron A , Drapkin R , Nucci MR , Medeiros F , Saleemuddin A , Garber J , Birch C , Mou H , Gordon RW , Cramer DW , McKeon FD , Crum CP
Published: November 2006

The tubal fimbria is a common site of origin for early (tubal intraepithelial carcinoma or TIC) serous carcinomas in women with familial BRCA1 or 2 mutations (BRCA+). Somatic p53 tumour suppressor gene mutations in these tumours suggest a pathogenesis involving DNA damage, p53 mutation, and progressive loss of cell cycle control. We recently identified foci of strong p53 immunostaining—termed ‘p53 signatures’—in benign tubal mucosa from BRCA+ women. To examine the relationship between p53 signatures and TIC, we compared location (fimbria vs ampulla), cell type (ciliated vs secretory), evidence of DNA damage, and p53 mutation status between the two entities. p53 signatures were equally common in non‐neoplastic tubes from BRCA+ women and controls, but more frequently present (53%) and multifocal (67%) in fallopian tubes also containing TIC. Like prior studies of TIC, p53 signatures predominated in the fimbriae (80–100%) and targeted secretory cells (HMFG2 + /p73−), with evidence of DNA damage by co‐localization of γ‐H2AX. Laser‐capture microdissected and polymerase chain reaction‐amplified DNA revealed reproducible p53 mutations in eight of 14 fully‐analysed p53 signatures and all of the 12 TICs; TICs and their associated ovarian carcinomas shared identical mutations. In one case, a contiguous p53 signature and TIC shared the same mutation. Morphological intermediates between the two, with p53 mutations and moderate proliferative activity, were also seen. This is the first report of an early and distinct alteration in non‐neoplastic upper genital tract mucosa that fulfils many requirements for a precursor to pelvic serous cancer. The p53 signature and its malignant counterpart (TIC) underline the significance of the fimbria, both as a candidate site for serous carcinogenesis and as a target for future research on the early detection and prevention of this disease. Copyright © 2006 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Quantitative structure‐activity relationship study of bitter di‐ and tri‐peptides including relationship with angiotensin I‐converting enzyme inhibitory activity
Authors: Wu Jianping , Aluko Rotimi E.
Published: November 2006

Bitterness represents a major challenge in industrial application of food protein hydrolysates or bioactive peptides and is a major factor that controls the flavor of formulated therapeutic products. The aim of this work was to apply quantitative structure‐activity relationship modeling as a tool to determine the type and position of amino acids that contribute to bitterness of di‐ and tri‐peptides. Datasets of bitter di‐ and tri‐peptides were constructed using values from available literature, followed by modeling using partial least square (PLS) regression based on the three z‐scores of 20 coded amino acids. Prediction models were validated using cross‐validation and permutation tests. Results showed that a single‐component model could explain 52 and 50% of the Y variance (bitterness threshold) of bitter di‐ and tri‐peptides, respectively. Using PLS regression coefficients, it was determined that hydrophobic amino acids at the carboxyl‐terminus and bulky amino acid residues adjacent to the carboxyl terminal are the major determinants of the intensity of bitterness of di‐ and tri‐peptides. However, there was no significant (p > 0.05) correlation between bitterness of di‐ and tri‐peptides and their angiotensin I‐converting enzyme‐inhibitory properties. Copyright © 2006 European Peptide Society and John Wiley & Sons, Ltd.
Optical spectroscopy properties of Tm ion in La3Ga5SiO14 single crystal
Authors: Wang Zengmei , Yin Yansheng , Yuan Duorong
Published: November 2006

High optical quality La3Ga5SiO14 (abbreviated as LGS):Tm single crystals with dopant concentrations of 1 at% Tm3+ ions were grown by the Czochralski method. The absorption spectrum and fluorescence spectrum of LGS:Tm crystals were measured at room temperature. Based on Judd–Ofelt method, the spectroscopic parameters were obtained, such as intensity parameters Ωt (t = 2, 4, 6), the experimental and theoretical oscillator strength, spontaneous emission probabilities, the radiative lifetime, and the fluorescence branching ratios. The calculated results showed that LGS:Tm is a potential solid‐state laser crystal and has probably realized the 1721 nm and 786 nm laser emission. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
In‐situ neutron reflectometry probing competitive swelling and de‐swelling of thin polystyrene films
Authors: Müller‐Buschbaum P. , Bauer E. , Maurer E. , Nelson A. , Cubitt R.
Published: November 2006

The competitive penetration of toluene with respect to oxygen, nitrogen and carbon dioxide into a thin and initially dry film of deuterated polystyrene (dPS) is compared to the reverse process of de‐swelling. In‐situ neutron reflectometry is used to follow the swelling and de‐swelling kinetics, allowing the determination of the total dPS thickness, roughness and solvent penetration. Swelling cannot be described in terms of case II diffusion due to the small film thickness and undersaturation results in a small swelling rate of 0.03 nm s–1. De‐swelling is slower by more than two orders in magnitude, thereby underlining the difficulty to remove once incorporated solvent molecules. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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Density of electron states in crystalline systems calculated in the presence and absence of the magnetic field
Authors: Olszewski S. , Roliński T.
Published: November 2006

It is demonstrated in terms of explicit calculations that the average density of states in a crystalline system remains unaffected by the presence of the external magnetic field. This is so on condition the magnetic field is weak enough to provide us with a large number of the Landau levels per energy unit. For a special case of a two‐dimensional crystalline system, the equivalence of the density of states obtained in the presence and the absence of the magnetic field can be shown in an analytic way. For three dimensions, the tightly bound s‐electron states in crystals having cubic symmetry are taken into consideration. Here the density of states calculated in the presence of the magnetic field is compared numerically with that of the field‐absent Bloch states acquired with the aid of Jelitto's method. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
Extraordinary superatom containing double shell nucleus: Li(HF)3Li connected mainly by intermolecular interactions
Authors: Sun Xiao‐Ying , Li Zhi‐Ru , Wu Di , Sun Chia‐Chung
Published: November 2006

The structure and properties of the Li(HF)3Li cluster with C3hsymmetry are investigated using ab initio calculations. This Li(HF)3Li is a metal–nonmetal–metal sandwich‐like cluster connected mainly by the intermolecular interactions. In the special cluster, the (HF)3containing the triangular F ring with the negative charges is sandwiched between two Li atom. It is interesting that under the action of the triangular F ring with the negative charges, the valence electrons of two Li atoms are pushed out to form the distended excess electron cloud that surrounds the Li(HF)3Li as a core. So the Li(HF)3Li cluster shows not only the electride characteristic, but new superatom characteristics as well. Several characteristics of the special superatom are found. First, the superatom contains the double shell nucleus. The internal nucleus is the regular triangular ring made of three F atoms with the negative charge and the outer‐shell nucleus is made up of three H and two Li atoms with the positive charge. Second, the bonding force of this superatom framework is mainly the intermolecular interaction force, the lithium bond, which is different from that (covalent bond or ionic bond) of the general superatom. Third, the interaction between the outer‐shell nucleus and the excess electron cloud is mainly the anti‐excess‐electron hydrogen bond. Fourth, the special superatom exhibits the new aromaticity (NICS = −8.37 ppm at the center of the regular triangular F ring), which is the aromaticity found in the cluster of the intermolecular interaction. This is the new knowledge of the aromaticity. Fifth, the large polarizability of the superatom is revealed. Further, the vertical ionization energy (VIE) of the superatom is low, 4.51 eV (<5.210 eV of the alkaline–earth metal Ba) so that it may be viewed as a superalkaline–earth metal atom. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
Analysis of phosphorylation sites on focal adhesion kinase using nanospray liquid chromatography/multiple reaction monitoring mass spectrometry
Authors: Ciccimaro Eugene , Hevko John , Blair Ian A.
Published: November 2006

An approach based on nanospray liquid chromatography/multiple reaction monitoring mass spectrometry (LC/MRM‐MS) was developed in order to analyze twenty‐nine phosphorylated and non‐phosphorylated tryptic peptides from focal adhesion kinase (FAK). All peptides monitored were resolved and showed excellent peak shape with the exception of one doubly phosphorylated peptide. Optimization of the LC method enabled the identification and subsequent monitoring of six important tyrosine phosphorylation sites on FAK, including phosphorylated Y397 (pY397), pY407, pY576, pY577, pY861, and pY925. This technique was able to identify sites of phosphorylation on FAK as well as qualitatively differentiate between autocatalytic and Src‐induced phosphorylation events. FAK was shown to have autocatalytic function, which resulted in efficient phosphorylation of Y397. FAK was also capable of autophosphorylation on residues Y407 and Y576, though apparently less effectively than autophosphorylation at Y397. Src was found to phosphorylate FAK at Y407, Y576, Y577, and Y861. The presence of Src increased the abundance of pY576 at low temperature indicating Src had particularly high kinase activity toward this residue. Furthermore, Src phosphorylated FAK at Y577 to produce FAK bis‐phosphorylated at Y576 and Y577. In addition, six novel sites of phosphorylation (Y148, Y347, Y441, T503, S850, and Y1007) were identified on FAK. Interestingly, Src phosphorylated FAK to form a peptide uniquely phosphorylated on Y407, together with substantial amounts of the bis‐phosphorylated pY397pY407 peptide. These findings will impact significantly on future studies of FAK activity since pY397 is often used as a measure of FAK activity and Src association. Copyright © 2006 John Wiley & Sons, Ltd.
Identification of N‐terminal modification for recombinant monoclonal antibody light chain using partial reduction and quadrupole time‐of‐flight mass spectrometry
Authors: Yu Lei , Remmele Richard L. , He Bing
Published: November 2006

Since most recombinant monoclonal antibodies (mAbs) contain glutamic acid or glutamate at their N‐terminus, cyclization of these residues to form pyroglutamate is an important degradation pathway that often occurs in therapeutic mAb development. In this work, a rapid method was developed to determine pyroglutamate at the N‐terminus of mAb light chain by liquid chromatography coupled with electrospray ionization on a quadrupole time‐of‐flight mass spectrometer (QTOF). High levels of pyroglutamate were found at the N‐terminus of the light chain of a typical recombinant mAb. The quantitative results were comparable to those obtained with a more conventional peptide mapping method. The direct method outlined here can be used to evaluate the impact of N‐terminal cyclization during the processing of recombinant mAbs. Copyright © 2006 John Wiley & Sons, Ltd.
Graviresponses in fungi and slime molds
Authors: Hock Bertold , Häder Donat‐P.
Published: November 2006

The analysis of gravisensing in fungi has not yet proceeded as far as in other systems, such as sensory cells for maintenance of equilibrium in crustaceans and vertebrates, Chara rhizoids or plant roots with regard to positive gravitropism. However, considerable progress has recently been made with several fungal systems in the field of graviresponses. This particularly holds true for the molecular basis of primary events. In this review three systems of increasing complexity are considered: the slime molds Physarum and Dictyostelium, which exhibit gravitaxis, the negative gravitropic sporangium of the zygomycete Phycomyces as a single cell structure with the fastest graviresponses known so far, and the fruit bodies of the basidiomycetes Coprinus and Flammulina as highly complex structures with the ability to generate positional information and cell signalling in the context of negative gravitropism.
Multiple Z‐Plasty in Pilonidal Sinus—A New Technique under Local Anesthesia
Authors: Sharma Pradeep Purushottam
Published: November 2006

Background

Pilonidal sinus is a common surgical condition. Though benign, it causes a lot of distress with its associated morbidity and financial loss to the patient. Many procedures have been tried, ranging from nonsurgical to surgical methods (both conservative and radical ones). It is well known that recurrences are low when the scar is away from the midline.

Materials and Methods

The author has described a new technique of multiple Z‐plasty for the treatment of pilonidal sinus that has been effective in the cure of this problem. This article reports a prospective, nonrandomized noncomparative preliminary clinical study of 115 cases of pilonidal sinus operated on by the author over 14 years.

Results

The results were compared with the results of other methods mentioned in the literature. There were only two recurrences.

Conclusions

The author proposes that multiple Z‐plasty can be considered as an option in the surgical treatment of pilonidal sinus.
Environmental influences on the spatial distribution of European hake (Merluccius merluccius) and red mullet (Mullus barbatus) in the Mediterranean
Authors: Maravelias Christos D. , Tsitsika Efthymia V. , Papaconstantinou Costas
Published: November 2006

Generalised additive models (GAMs) were used to test the hypotheses that red mullet (Mullus barbatus) and hake (Merluccius merluccius) abundances are related to the bathymetry, spatial location and the temperature‐based variability of the NE Mediterranean. Data were collected during a 2‐year period (1996–1997) of quasi‐synoptic sampling using demersal trawl surveys in the northern Aegean Sea. The results of this study supported these hypotheses. It was found that geographic position and sea bottom characteristics influence the temporal distribution patterns of red mullet and hake. Data are presented that reveal species‐specific aggregation patterns and an important habitat utilisation of the area. The modelled species’ abundances showed a strongly non‐linear dependence on the explanatory covariates. This study, although not directly dealing with spawning, also provided evidence that red mullet and hake demonstrate environmental and bathymetric preferences in the months posterior to spawning. Mean red mullet abundance was consistently highest in areas with warmer bottom waters in the east and west than in the centre, these areas having shallower depths (35–60 m) and bottom temperatures around 19°C. The red mullet appeared to avoid the cold bottom waters (<16°C) of the deeper regions. Results indicated that areas with the highest hake abundances were located in waters of ∼160 m having bottom temperature of ∼16°C and avoided the shallower waters (<70 m) regardless of their bottom temperature. The present findings also suggested that colder bottom waters at all depths were associated with lower‐than‐average hake abundance. Red mullet and hake preferences for areas with specific bathymetric and ocean environmental conditions are believed to be linked to the oceanography of the NE Mediterranean ecosystem.
Sugar fatty acid ester surfactants: Base‐catalyzed hydrolysis
Authors: Baker Irene J. A. , Furlong D. Neil , Grieser Franz , Drummond Calum J.
Published: November 2006

Rate constants for the base‐catalyzed hydrolysis of sucrose laurate, sucrose α‐sulfonyl laurate, and sucrose α‐ethyl laurate were measured at several temperatures in pH 11 buffer. Activation energies and Arrhenius factors for the hydrolysis reactions were determined. At 27°C, sucrose laurate hydrolyzed fastest and sucrose α‐ethyl laurate slowest. Activation energies and Arrhenius factors showed that both steric and electronic factors affect the rates of ester hydrolysis. Other work has shown that bacterial hydrolysis of sugar fatty acid esters is inhibited in the presence of either α‐sulfonyl or α‐alkyl groups. A kinetic study of base‐catalyzed ester hydrolysis has revealed reasons for the inhibition of bacterial hydrolysis and provided information regarding ester stability at elevated pH.
Synthesis, characterization, and surface properties of new bis‐quaternary pyrimidinium surfactants
Authors: Pegiadou‐Koemtzopoulou S. , Papazoglou V. , Kehayoglou A. H.
Published: November 2006

New bis‐quaternary pyrimidinium surfactants were synthesized by reacting 4‐amino‐5‐phenyl‐pyrimidine with alkylene dibromides (C8−C12). Structural assignments of the new compounds were made on the basis of elemental analysis, infrared, and 1H nuclear magnetic resonance spectroscopy. Critical micelle concentrations, as determined by tensiometry, were lower than those of previously studied corresponding monoquats. The rate of drop coalescence in an oil (hepatane)/water emulsion of a bis‐quat was lower than that of the corresponding monoquat, showing a higher emulsification efficiency for the former.
Composition of mixed anionic/nonionic surfactant micelles
Authors: Akbaş Halide , Işcan Mehmet , Sidim Taliha
Published: November 2006

A proposed method of determining the composition of mixed micelles in equilibrium with monomer of known composition is described. The systems were sodium dodecyl sulfate‐polyoxyethylene 23 lauryl ether (Brij 35) in water and in 0.1 M sodium chloride solution at 25°C. This technique applies the Gibbs‐Duhem equation to the mixed micelle, which is treated as a pseudophase. This proposed methodology which needs only critical micelle concentration data as a function of monomer composition, is applied to an anionic/nonionic surfactant pair. The calculated monomer‐micelle equilibrium is found to be very similar to the much‐used regular solution for nonideal systems.
Chemical structure/property relationships in surfactants. 17. N‐substituted‐N‐acyl glycinates in pure and synthetic hard river water
Authors: Zhu Yun‐Peng , Rosen Milton J. , Morrall Stephen W.
Published: November 2006

The surface properties [effectiveness of surface tension reduction (γCMC), critical micelle concentration (CMC), efficiency of surface tension reduction (pC20), maximum surface excess concentration (ΓCMC), minimum area/molecule at the interface (Amin), and the CMC/C20) ratio] of well‐purified N‐substituted glycine derivatives, having the structural formula RC(O)N(R′)CH2COONa, where RC(O)=lauroyl, myristoyl, or oleoyl, and R′=Et, Pr, Bu, CH2CH2OH or CH2CH2CH2OCH3, were investigated at 25°C in hard river water and distilled water. These surfactants show greater surface activity in hard river water than in distilled water. The effect of both the main alkyl chain R and the N‐substituent R′ on surface properties was elucidated, the oleoyl group showing properties equivalent to that of a C16 saturated acyl group. A linear relationship was observed between the pC20 or CMC values and the number of carbon atoms in the alkyl chain R or in R′ when it was alkyl. With increase in the number of carbon atoms in either R or the N‐substituent R′ when it is alkyl, both pC20 and micelle‐forming ability increase, although the effect of R′ on the foregoing two surface properties is lower than that of R. When R′ is (CH2)3OCH3, however, the results suggest that R′ is only partly removed from contact with the aqueous phase either upon adsorption at the water/air interface or upon micellization. It increases Amin, is equivalent only to an ethyl group in its effect on pC20 and to a methyl group in its effect on CMC, and, in contrast to the effect of R′ when it is alkyl, produces no increase in the CMC/C20 ratio. As a result, γCMC increases with R when R′ is alkyl and decreases with R when R′ is (CH2)3OCH3.
Assembly properties of the aggregates resulting in the solubilization of phosphatidylcholine bilayers by sodium cholate
Authors: de la Maza Alfonso , Parra José Luis
Published: November 2006

The interaction of sodium cholate with phosphatidylcholine liposomes was investigated. Permeability alterations were detected as a change in 5(6)‐carboxyfluorescein (CF) released from the interior of vesicles and bilayer solubilization as a decrease in the static light‐scattered by liposomes. Free surfactant concentration at subsolubilizing and solubilizing levels showed, respectively, values that were lower than and similar to the surfactant critical micelle concentration, and indicated that permeability alterations and solubilization were determined, respectively, by the action of surfactant monomer and by the formation of mixed micelles. A direct relationship was established in the initial steps [effective surfactant/lipid molar ratio (Re) lower than 0.07] between the growth of vesicles, the leakage of entrapped CF (fluidity of vesicles), and Re. These changes could be correlated with the increasing presence of surfactant molecules in the outer monolayer of vesicles and its saturation. The subsequent increase in Re led to a lower growth of vesicles in coexistence with a similar increase in the CF release. This behavior could be related to a increased rate of flipflop of the sodium cholate molecules, making the inner monolayer also available for the interaction with added surfactant. A direct dependence was also established in the initial solubilization steps (Re values up to 0.6) between the surfactant‐phosphatidylcholine aggregate size, the static light‐scattering of the system, and Re. In the Re interval 0.36–0.84 mixed vesicles and mixed micelles coexisted.