bluuebunny/crossref_metadata_2025 huggingface dataset:
Solute—Solvent Interactions Examined by the Nuclear Overhauser Effect
Authors: Gerig J. T.
Published: August 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Electrons as a Reagent in Solid‐Phase Organic Synthesis (Eur. J. Org. Chem. 26/2007)
Authors: Mentel Matthias , Breinbauer Rolf
Published: August 2007

The cover picture shows that electrons have become a valuable reagent in Solid‐Phase Organic Synthesis (SPOS). Through the addition of electron‐transfer reagents or catalysts, new transformations are now possible within the environment of polymer‐bound substrates, which significantly expands the toolbox for solid‐phase organic synthesis. The picture depicts how an electron donated by a metal complex cleaves the linker of a substrate to the polymer chain. Details are presented in the Microreview by M. Mentel and R. Breinbauer on pp. 4283 ff.
Parasite Infestation of Antocha (Antocha) bifidaAlexander, 1924 (Diptera: Tipulidae) by Water Mite Larvae (Sperchon plumiferThor, 1902) in the Middle Reaches of the Shinano River, Central Japan
Authors: Hirabayashi Kimio , Fukunaga Yachiyo
Published: August 2007

This is the first report of parasite infestation of Tipulidae by water mite larvae in the middle reaches of a river in Japan. Forty‐four species of adult crane flies were identified. The most abundant species was Antocha (Antocha) bifida Alexander 1924 with 22204 individuals (76.5% were male). Some 2113 individuals (9.5%) were parasitized by water mites, viz., Sperchon plumifer Thor 1902 (maximum: 40/host, mean value: 3.5 ± 2.5/host). 73.1% of S. plumifer larvae were attached to the abdomen. Many S. plumifer larvae parasitized A. bifida adults from late May to early July, but after a small flood, few S. plumifer larvae were collected. Floods have a major impact on both the A. bifida population and on its parasite, the S. plumifer larval population. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Particulate Organic Matter (POM) in the Humid and Wet Zones of the Ellegirini River, Kenya
Authors: Mwithali M'Erimba Charles , Leichtfried Maria , Mutuku Mathooko Jude
Published: August 2007

Field experiments to quantify the amount of particulate organic matter as an energy source for the system were conducted between February 2002 and June 2002 in humid and wet zones of the Ellegirini River in Kenya. The experiment involved collecting ten random samples from each zone. The humid zone held a hundred times more coarse particulate organic matter (CPOM) ash‐free dry mass than the wet zone, where the stream current and other influencing parameters decreased CPOM amount. In conclusion it can be said that these significant differences are the result of different attributes between these two zones. Factors like current velocity, discharge or the absence of CPOM holding structures are responsible for low CPOM in the wet zone. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Habitat Complexity and Invertebrates in Selected Alpine Springs (Schütt, Carinthia, Austria)
Authors: Staudacher Karin , Füreder Leopold
Published: August 2007

The invertebrate fauna from eight selected springs of the landslide area of Schütt (Carinthia, Austria) with contrasting environmental factors was investigated. The role of habitat structure on the community composition was studied with a particular focus on the spring‐dwelling animals colonizing the aquatic and the adjacent aquatic‐terrestrial transition zones. The crenocoenosis was predominantly composed of Chironomidae, Plecoptera, Trichoptera, Mollusca and Ostracoda and the number of spring‐specialists was high. Habitat complexity, variable microhabitat composition and the concomitance of lotic and lentic areas in the eucrenal zone furthered a high species diversity and abundance. Even the aquatic‐terrestrial transition zone was inhabited by high numbers of crenobionts and crenophiles. Moreover, the connectivity of aquatic and terrestrial habitats positively affected the structural and functional organisation of invertebrate assemblages in the spring biotopes. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Hyporheic Biofilm Particulate Organic Carbon in a Small Lowland Stream (Sitka, Czech Republic): Structure and Distribution
Authors: Koutný Jan , Rulík Martin
Published: August 2007

Bacterial abundance, biomass and particulate organic carbon (POC) were determined in the hyporheic sediments <1 mm. The fine fraction (<0.063 mm) and coarse fraction (0.063–1 mm) were analysed separately. The coarse fraction was dominant (95.5%) and its POC content contributed the major proportion (on average 65%) of the total POC (TPOC). The changes in spatial distribution of TPOC were due to the variation in POC in the fine fraction. Bacteria in the fine fraction contributed on average to 62.9% of the total bacterial abundance and to 51.7% of the total bacterial biomass, despite the fact that the fine fraction represented only ∼4.5% of the sediment <1 mm. Our results stress the importance of the fine sediment fraction for bacteria as well as for spatio‐temporal distribution of biofilm POC. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The Ecological Effect of Drought on the Macroinvertebrate Fauna of a Small Intermittent Stream – An Example from the Czech Republic
Authors: Řezníčková Pavla , Pařil Petr , Zahrádková Světlana
Published: August 2007

The impact of an unstable hydrological regime on macroinvertebrates in an intermittent stream (with periodic summer droughts in particular stretches) was investigated in two successive years with differing climatic conditions. Ten series of macroinvertebrate samples were taken from two sampling sites between April 2002 and October 2003. Total abundance, taxa richness, main faunal groups, and life strategies were assessed in order to describe the changes in the macroinvertebrate assemblages. Periodic dry periods caused a decrease in macroinvertebrate density in the intermittent stretch, whereas they had no negative influence on number of taxa. Before the drought, the density of permanent fauna decreased and the number of r‐strategists rose and stayed at a high level in first samples in the after‐drought period. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Method for identifying the surface wave frequency band‐gap of EBG structures
Authors: Xu Huiliang , Lv Yueguang , Luo Xiangang , Du Chunlei
Published: August 2007

In this letter, a method, patch antenna and microstrip method (PAMM), for identifying the surface‐wave band‐gap of electromagnetic band‐gap (EBG) structures is introduced. The key idea of PAMM is that a patch antenna, fed by a microstrip line, is served for a radiator and an open‐end microstrip line with characteristic impedance of 50 Ω, is employed as a detector for the electromagnetic field along the substrate. Several rows of EBG structures are inserted between the detector and the radiator. The band‐gap range of surface‐wave can be identified by measuring the transmission through the detector and the radiator. Simulation results show that the transmission coefficient with EBG presence is lower than that of case without EBG absence above 10 dB. On the other hand, the gain of the antenna increases 1.9 dB when four rows of EBG are present. The results verify that the propagation of surface‐wave is suppressed and the method is effective. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2668–2672, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22812
A dual band CMOS complementary Colpitts voltage controlled oscillator
Authors: Jang Sheng‐Lyang , Lee Shao‐Hua , Chiu Chun‐Yuan , Lee Chien‐Feng
Published: August 2007

A new fully integrated, dual‐band CMOS voltage controlled oscillator (VCO) is presented. The VCO is composed of two complementary Colpitts VCOs and is implemented in 0.18‐μm CMOS technology with 2‐V supply voltage. The circuit allows the VCO to operate at two resonant frequencies with a common LC tank. This VCO is configured with 2.4‐ and 5.2‐GHz frequency bands with differential outputs. The dual‐band VCO operates at 2.39–2.68 GHz and 4.84–5.58 GHz. The phase noises of the VCO operating at 2.4 and 5.13 GHz are −121.11 and −111.76 dBc/Hz at 1‐MHz offset, respectively, while the VCO draws 7.45/5.92 mA and 14.9/11.84 mW consumption at high/low frequency band from a 2‐V supply. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2634–2637, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22814
Loose GMRES method for efficient solution of EFIE in the MLFMA context
Authors: Ding D. Z. , Rui P. L. , Chen R. S. , Fan Z. H.
Published: August 2007

The loose generalized minimum residual method (LGMRES) accelerated by multilevel fast multipole algorithm (MLFMA) is discussed for solving large dense linear systems that arise in the electric field integral equation (EFIE) formulation of electromagnetic scattering problems. The LGMRES is used to improve convergence by relieving restarting effect in the convensional GMRES iterative method, and the MLFMA is used to speed up the matrix‐vector product operations. As a result, nearly eight times convergence improvement is achieved for electromagnetic scattering (EM) from three‐dimensional (3D) conducting bodies. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2661–2665, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22816
Study on frequency splitting based on distributed Bragg reflector fiber laser
Authors: Jian‐Hua Luo , Bo Liu , Wei‐Hua Zhang , Shu‐Zhong Yuan
Published: August 2007

In this paper, we analyzed the frequency splitting phenomena when distributed Bragg reflector (DBR) fiber laser was influenced by lateral pressure. We gave the relationship of the frequency interval and the lateral pressure. This frequency splitting phenomena is based on Intracavity birefringent effects which are modulated by lateral pressure. So, this frequency splitting phenomena could be used in sensing pressure in the future. The pressure sensor which is based on the frequency splitting had more merits such as simple structure and frequency readable. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2628–2630, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22818
Stacked helix monopole antenna with vertical lines for broadband operation
Authors: Jung Jinwoo , Lee Hyeonjin , Lim Yeongseog
Published: August 2007

A novel stacked helix antenna with vertical lines is presented for broadband operation, and the impedance and radiation characteristics of the antenna are investigated. The proposed antenna achieved a bandwidth of approximately 34.2% with an S11 < −10 dB, which covers the DCS, PCS, UMTS, and WiBro bands. Omnidirectional radiation patterns are obtained for frequencies across the operating bands. Moreover, in discussion of the experimental results of the constructed prototype, the electrical characteristics of the proposed antenna appear to be attractive for mobile terminals and repeater applications. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2739–2742, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22821
Design of compact dual‐band bandpass filters using λ/2 and combined λ/4 stepped‐impedance resonators
Authors: Lee Ching‐Her , Hsieh Yi‐Huan , Ho Min‐Hua
Published: August 2007

This paper presents a compact dual‐band bandpass filter (BPF) that consists of a pair of L‐shape half‐wavelength (λ/2) stepped‐impedance resonators (SIRs) and an inverted Z‐shape resonator. The latter is actually a combined structure of two λ/4 SIRs along with a magnetic coupling in between and hence designed to reduce the circuit size. Cross‐coupled SIR configuration and 0° tapped‐feed structures are adopted to introduce attenuation poles around the passband edges for selectivity improvement. A wider −20‐dB upper stopband is achieved by properly separating the third resonant frequencies of the SIRs of different types. The newly designed dual‐band BPF was verified by circuit implementation, and a very good agreement between the simulated and measured results was observed. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2703–2706, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22823
Fast and accurate analysis for the directivity of circular‐shape antennas using optimal neural networks
Authors: Silva P. H. da F. , Passos M. G. , d'Assunção A. G.
Published: August 2007

This article describes the application of the optimal transfer function neural network methodology for fast and accurate function approximation of Q‐integrals, that appears in directivity expressions of circular‐shape antennas, such as loop, microstrip patch, and aperture in an infinite ground plane. These directivity expressions were revisited and linked in terms of Q‐type power‐radiation integrals. For each directivity approach using optimal neural networks–closed‐form expressions, series of Bessel functions, and adaptive Lobatto integration, the numerical results are presented and discussed in terms of accuracy and computational cost. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2721–2726, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22839
Compact band‐notched ultra‐wideband printed antenna
Authors: Ding Yi , Wang Guang‐Ming , Liang Jian‐Gang
Published: August 2007

A novel and compact ultra‐wideband (UWB) printed monopole antenna with extended band‐notched designs is presented. The antenna with a total size of 20 mm × 35 mm operates in a band from 3 to over 11 GHz (VSWR ≤ 2), and shows omnidirectional radiation with a low cross‐polarization in the range of the operated band. Measured results indicate that the antenna presents a notched‐band from 5.1 to 6 GHz for VSWR ≥ 3:1, which covers the wireless local area network (WLAN) band. The notched‐band is produced by an embedded resonant cell (ERC). Experimental results show that the band‐notched function can be controlled by adjusting the length of the ERC and area of the slot. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2686–2689, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22842
0.35‐μm SiGe BiCMOS variable‐gain power amplifier for WiMAX transmitters
Authors: Liao Hsien‐Yuan , Chen Kuan‐Yu , Deng Joseph D.‐S. , Chiou Hwann‐Kaeo
Published: August 2007

A 0.35‐μm SiGe BiCMOS variable‐gain power amplifier for WiMAX transmitters is presented. A voltage‐controlled variable resistor is used to control the gain of the linear amplifier. An open‐collector adaptive bias is utilized to obtain high linearity and efficiency. The measured power amplifier achieves a power gain of 22.2 dB, an output power of 20.6 dBm, and a power‐added efficiency of 24.4% with 10‐dB tuning range of linear gain. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2750–2753, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22851
Towards dispersion characteristics for a new unconventional metal‐clad optical waveguide
Authors: Shahi A. K. , Singh Vivek , Ojha S. P.
Published: August 2007

Using Goell's point matching method under weak guidance condition, the modal characteristic equations of a curvilinear triangular cored optical waveguide are obtained in three cases. In one case the proposed waveguide has on its one side a conducting material and other two sides are bounded by dielectric material. We describe it as dielectric‐dielectric‐metal (DDM) waveguide. In other case we consider both the boundaries conducting. We call this as metal‐metal‐dielectric (MMD) waveguide. Finally, we consider all the boundaries conducting. We call this as a metal‐metal‐metal (MMM) waveguide. Results obtained in all three cases are compared. It is found that for a given V‐value the DDM waveguide will support more modes than MMD and MMM waveguides. Therefore, the MMD or MMM waveguides may be used as a mode filter. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2709–2713, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22854
A 22 GHz cascode CMOS VCO using frequency doubler
Authors: Park Bonghyuk , Lee Seungsik , Hong Songcheol , Choi Sangsung
Published: August 2007

This paper presents a fully integrated cascode CMOS LC VCO using frequency doubler for oscillating at 22 GHz band. A symmetrical cascode coupling topology is implemented with negative conductance scheme for increasing the quality factor and output swing. Therefore, this architecture improves the phase noise characteristic in 0.18 μm CMOS technology. In order to oscillate at 22 GHz band the frequency doubler (clipper) is used. The measured phase noise is −102.4 dBc/Hz at the 1 MHz offset frequency. The tuning range of 1.32 GHz is obtained with the control voltage from 0.5 to 1.6 V. The current consumption of the VCO and the frequency doubler has 11.8 mA from 1.8 V supply. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2870–2873, 2007; Published online in Wiley InterScience (www.interscience.wiley.com).DOI 10.1002/mop.22857
Analog predistortion power amplifiers using IMD sweet spots for WCDMA applications
Authors: Lee Yong‐Sub , Lee Mun‐Woo , Jeong Yoon‐Ha
Published: August 2007

An analog predistortion power amplifier (PA) using intermodulation distortion (IMD) sweet spots for linearity improvement in wide‐band code division multiple access (WCDMA) applications is represented. A third‐order predistorter is used to cancel the IM3 components when the IM5 components are significantly reduced by the IMD5 sweet spots of the PA. For experimental validation, a 30‐W PEP LDMOSFET PA is implemented and tested for two‐tone and 4‐carrier WCDMA signals at 2.14 GHz. The measured results show that the notable linearity improvement is obtained over a whole output power range. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2838–2841, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22859
A voltage‐controlled varactorless LC‐tank oscillator with a transformer‐feedback technique
Authors: Yang Ching‐Yuan , Tsai Meng‐Ting
Published: August 2007

A differential‐voltage‐controlled LC oscillator employs a gm‐tuned technique instead of a varactor is presented, verified, and measured. The design was demonstrated in a standard 0.18‐μm CMOS process. The oscillator can operate at the range of 4.73–5.05 GHz under a 1.8‐V supply voltage. The measured phase noise is −100.76 dBc/Hz at 100‐kHz frequency offset and −121.53 dBc/Hz at 1‐MHz frequency offset away from the 4.73‐GHz carrier with power consumption of 6.48 mW. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2808–2810, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22861
Dual‐bandgap characteristics of spurline filters and its circuit modeling
Authors: Liu Haiwen , Sun Lingling , Shi Zhiguo
Published: August 2007

A novel asymmetrical spurline filter is introduced in this article. Its dual‐bandgap characteristics are reported for the first time and can be adjusted by changing the difference between the two spurlines' lengths. Moreover, a simple circuit model is set up for the new filter by using two LCR‐resonators. The proposed spurline filter and its circuit model are discussed and verified by a good agreement between simulations and measurements. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2805–2807, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22862
Self and mutual admittance of CPW‐FED slots on conductor‐backed two‐layer substrate
Authors: Jacobs J. P.
Published: August 2007

A characterization of the mutual admittance between CPW‐fed slot antennas on a practically feasible conductor‐backed two‐layer substrate is provided in conjunction with a characterization of isolated slot resonant self‐properties. This data is of interest for linear array design purposes. Numerical results are validated by a measurement. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2798–2802, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22866
Monopole‐like antenna for GSM, UMTS, and WLAN applications
Authors: Krzysztofik Wojciech J.
Published: August 2007

The microstrip planar monopole‐like antenna, MPM, capable of multiband operation is proposed. The MPM antenna constructed as microstrip 50‐Ω line loaded by the two planar resonant strips. The strips and the microstripline are photo‐etched on microwave laminate Rogers TMM4. The inner loaded strips resonating as a quarter‐wavelength structure and the outer folded strip resonating as both a quarter‐wavelength and a half‐wavelength structure. The flat (∼0.002 λ) MPM antenna, 12 mm (<0.1 λ) in height and 30 mm in width has been constructed, and the obtained bandwidths cover the four bands of three digital communication systems, centered: at 900 MHz and at 1800 MHz for the GSM, at 1900 MHz for PCS, and at 2050 MHz for UMTS, respectively. Results of design, simulations, and experiments are presented. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2766–2769, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22867
A fully integrated concurrent dual‐band low‐noise amplifier using InGaP/GaAs HBT technology
Authors: Lin Yu‐Tso , Lu Shey‐Shi
Published: August 2007

A fully integrated concurrent dual‐band low noise amplifier using InGaP/GaAs HBT technology is demonstrated for the first time. A new methodology is proposed so as to achieve simultaneous narrow‐band gain and impedance matching at multiple frequencies. The experimental results showed that input return losses of −16.2 and −12.1 dB, voltage gains of 16.8 and 20.1 dB, and noise figures of 2.72 and 2.88 dB were obtained at 2 and 4.6 GHz, respectively with power consumption of 12 mW. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2763–2765, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22868
Capacitively loaded Wilkinson power divider with size reduction and harmonic suppression
Authors: Li Jia‐Lin , Qu Shi‐Wei , Xue Quan
Published: August 2007

A compact Wilkinson power divider with harmonic suppression is investigated. The size reduction is achieved by attaching two lumped capacitors in the middle of the two quarter‐wavelength branches of the conventional one. Also, the harmonic suppression is realized as a result of the capacitive loading. Centered at 1.5 GHz, a demonstrator power divider is designed and confirmed by experiments. A size reduction of 48% and nth harmonic suppression are obtained as comparing with the conventional one. Both simulations and measurements are presented, and a good performance is observed. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2737–2739, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22869
Millimeter wave inspection of concealed objects
Authors: Jaeger Irina , Zhang Lixiao , Stiens Johan , Sahli Hichem , Vounckx Roger
Published: August 2007

Imaging concealed objects with a millimeter‐wave coherent beam is accompanied with speckle. Two tools were chosen to improve visibility of concealed objects for security or industrial inspection: a speckle contrast image (image processing tool) and a Hadamard diffuser (mechanical tool). We report more then 50% speckle reduction over the full W‐band. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2733–2737, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22870
Calibration of accelerometers by using an extrinsic fiber optic probe
Authors: Binu S.
Published: August 2007

This article reports the principle of operation, design aspects, experimentation, and performance of an extrinsic fiber optic probe for the calibration of accelerometers. The device consists of fiber optic transmitter, fiber optic probe, minishaker type 4810, power amplifier type 2706, accelerometer, conditioning amplifier, dynamic signal analyzer, photodiode detector, and a digital multimeter. In this technique, the vibration amplitudes are measured simultaneously using an accelerometer and extrinsic fiber optic probe and the results are compared. The agreement between the results obtained from accelerometer and from the fiber optic probe method shows that the latter can be a promising alternative technique for the measurement of vibration amplitude and hence for the calibration of accelerometers. The stability of the sensor, high sensitivity, and the simplicity of the design, low cost of fabrication, make it suitable for real field applications. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2700–2703, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.4204
K‐band single balanced mixer for ultra‐wideband radar in 0.18‐μm CMOS technology
Authors: Yu Han‐Yeol , Choi Sung‐Sun , Kim Sung‐Hyun , Kim Yong‐Hoon
Published: August 2007

A K‐band single balanced mixer for ultra‐wideband radar using a 0.18‐μm CMOS technology is presented. The designed mixer was applied to LC ladder matching technique on RF port and Marchand type balun with slot pattern ground on LO port for wideband operation, respectively. The mixer achieves 3‐dB bandwidth of 1.4 GHz, power conversion gain of 1.2 dB, and 1‐dB compression point of −3 dBm at RF frequency of 24 GHz and LO frequency of 24.1 GHz. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2697–2700, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22872
A novel dual‐band branch line coupler based on strip‐shaped complementary split ring resonators
Authors: Niu Jia‐Xiao , Zhou Xi‐Lang
Published: August 2007

In this article, a novel dual‐band branch line coupler is presented. The dual‐band operation is realized by the LH‐RH transmission line composed of strip‐shaped complementary split ring resonators (CSRRs) and series gap, which can produce LH band around 900 MHz and RH band around 1800 MHz. The performances of the designed device at two operating frequencies are demonstrated by simulated and measured results, which are in good agreement. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2859–2862, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22873
Design of UWB planar antenna with subband rejection capability
Authors: Abbosh A. M.
Published: August 2007

A simple guideline for designing a compact ultra wideband planar antenna is presented. The proposed antenna has the capability to reject any undesired subband within the whole bandwidth of its operation by incorporating a tuning slot within the radiating structure. Using GML1032 dielectric substrate with a relative permittivity of 3.2, the designed antenna features a compact size of 27 × 27 mm2. Results of the measurement show that the designed antenna has a 10 dB return loss bandwidth from 2.8 GHz to more than 11 GHz excluding any undesired subband, such as the 4.9–5.9 GHz band assigned for IEEE802.11a and HIPERLAN/2. The antenna has near omnidirectional characteristics, and its radiation efficiency is higher than 90% over the whole pass‐band. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2855–2859, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22874
Compact Wilkinson power divider with harmonic suppression
Authors: Tu Wen‐Hua
Published: August 2007

This letter presents a compact Wilkinson 3‐dB power divider with the third harmonic suppression. The equivalent T‐shaped microstrip lines are designed to replace the two quarter‐wavelength microstrip lines of the conventional power divider. The equivalent lines achieve the same fundamental responses with the conventional lines while the equivalent lines are bandstop filters at the third harmonic frequency to suppress the third harmonic signals. A 47‐dB third harmonic suppression is achieved. Furthermore, the proposed power divider is compact and achieves 16% size reduction in comparison to the conventional power divider. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2825–2827, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22875
Design of a wide and multiband aperture‐stacked patch antenna with reflector
Authors: Jang Won‐Gyu , Choi Jae‐Hoon
Published: August 2007

A novel wide and multiband aperture‐stacked patch antenna is presented. It consists of a single microstrip patch with two pairs of slits, resonant aperture, and a thin reflector patch to reduce the back radiation. By the proper choice of slit length, the required multiband characteristics including the small patch size (∼0.25 λo) are realized. By controlling the spacing between the aperture and reflector, the front‐to‐back ratio at upper frequency band can be optimized. Improved radiation characteristics with high gain (5.9–9.0 dBi) have also been observed. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2822–2824, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22876
A novel broadband antenna for passive UHF RFID transponders offering global functionality
Authors: Fang Zhijiang , Jin Ronghong , Geng Junping , Sun Jing
Published: August 2007

In this letter, a novel broadband dipole antenna for UHF RFID transponder, which offers global functionality across different regulatory areas is proposed. The proposed antenna has a measured bandwidth from 0.83 to 1 GHz (18.5%) where the power reflection coefficient is below −10 dB for conjugate matching with an EPC class 1 Gen 2 chip, which is sufficient to cover the whole band (0.86–0.96 GHz) regulated by EPC global class 1 Gen 2 protocol (ISO/IEC 18000 6c). Additionally, an equivalent circuit model for such kind of antenna is presented to illustrate the broadband impedance matching characteristic between the antenna and the chip. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2795–2798, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22877
Leitliniengerechter Einsatz der Setrone. Übelkeit und Erbrechen bei onkologischen Therapien
Authors: Nemec Karin
Published: August 2007

Die Erfolge in der antiemetischen Therapie der letzten 25 Jahre sind beachtlich: So konnte die Rate der kompletten Emesis‐Unterdrückung von 30 % in den achtziger Jahren auf 70 % in den 1990er Jahren und etwa 85 % im Jahr 2006 verbessert werden. Diese Erfolge wurden durch die Entwicklung potenter, hochspezifischer Antiemetika sowie deren Leitliniengerechten Einsatz zur Prävention von Nausea und Emesis möglich. In der Zukunft wird sich das Hauptaugenmerk auf den Einsatz von Antiemetika bei Kindern, die geschlechtsspezifischen Unterschiede im Ansprechen auf die antiemetische Prophylaxe sowie die noch immer schlecht beherrschbare Form des antizipatorischen Erbrechens richten. Eine weitere Herausforderung sind Patienten, die als Non‐Responder auf die Antiemese zu bezeichnen sind (“therapierefraktäres Erbrechen”). Diesen Patienten könnten die Erkenntnisse aus der pharmakogenomischen Forschung zugute kommen: vor allem Variationen im Metabolismus der Setrone durch CYP450‐Genotypen sowie Variationen im 5‐HT3‐Rezeptor‐Gen könnten für den mangelnden Erfolg der Antiemese verantwortlich sein.
Postoperative Nausea und Emesis (PONV). Pathophysiologie, Risikofaktoren und Therapie
Authors: Wurglics Mario , Spiegl Franz
Published: August 2007

Das Management der PONV hat in der letzten Dekade, nicht zuletzt durch die Einführung der Setrone, eine deutliche Qualitätsverbesserung erfahren. Die 5‐HT3‐Antagonisten Ondansetron, Dolasetron, Granisetron und Tropisetron reduzieren außerordentlich effektiv die Inzidenz der PONV und zeichnen sich, im Vergleich zu klassischen Antiemetika, durch ein günstigeres Nebenwirkungsprofil aus. Im Allgemeinen sind die vier Verbindungen äquieffektiv in der Prophylaxe bzw. Therapie der PONV. Geringfügige Unterschiede gibt es bezüglich der Pharmakokinetik und der Pharmakodynamik, was die Variationen in der Wirkdauer, den Einfluss auf die circadiane Rhythmik oder verschieden ausgeprägten Interaktionen erklärt.

Generelle Einigkeit besteht heute darüber, dass eine PONV‐Prophylaxe nach Abschätzung des individuellen Risikos des Patienten in drei Stufen durchgeführt wird. Demnach ist eine Prophylaxe bei niedrigem Risiko nicht gerechtfertigt. Erst ab einem mittleren Risiko wird Präventiv mit einem Setron, Dexamethason oder Droperidol therapiert. Bei Hochrisikopatienten kann eine Kombination mehrerer Wirkstoffe in der Prophylaxe notwendig sein.

Ist trotz Prophylaxe eine Therapie erforderlich, dann sollte ein Antiemetikum zur Anwendung gelangen, welches noch nicht zuvor als Prophylaktikum eingesetzt wurde. Insgesamt scheinen zur Therapie der PONV geringere Dosierungen als zur Prophylaxe auszureichen.
Ein neues Target für neue Antibiotika – die Glycosyltransferase
Authors: Holzgrabe Ulrike
Published: August 2007

Weltweit breiten sich Resistenzen und Multiresistenzen gegen nahezu alle Antibiotika mit großer Geschwindigkeit aus. Deshalb ist die Auffindung neuer Zielstrukturen extrem wichtig. In den letzten 40 Jahren gibt es aber nur zwei Beispiele für Antibiotika mit neuem Wirkmechanismus, und zwar das Oxazolidinon Linezolid und das Lipopeptid Daptomycin. Beide Antiinfektiva sind auf Grund von unerwünschten Wirkungen bzw. des eingeschränktem Wirkspektrum nur in besonderen Fällen einsetzbar.
Humane Stammzellen aus Fruchtwasser
Authors: Winckler Thomas
Published: August 2007

Pluripotente humane Stammzellen haben ein großes therapeutisches Potential, aber ihre Gewinnung aus Embryonen ist ethisch hoch problematisch. Möglicherweise haben neu entdeckte fötale Stammzellen aus Fruchtwasser ein ähnlich großes Potential wie embryonale Stammzellen.
Eine HIV‐Infektion rückgängig machen?
Authors: Winckler Thomas
Published: August 2007

Schon häufiger haben wir an dieser Stelle über neue Strategien zur Therapie der HIV‐Infektion berichtet. Der heilige Gral der AIDS‐Therapie wäre es vielleicht, eine HIV‐Infektion zu heilen, indem man das Virus wieder aus den befallenen Zellen entfernt.
Klinische Forschung unterstützen
Authors: Eggers Thies
Published: August 2007

Neues Internetportal vermittelt klinische Studien für Probanden und Patienten. Im Februar startete www.probanden.info, eine Vermittlungsstelle für Probanden und Patienten von klinischen Studien im Internet. Auf dem Portal können Interessenten kostenlos nach aktuellen Studien in ganz Deutschland suchen. Wissenschaftler können über einen Eintrag eine große Zahl potentieller Versuchsteilnehmer erreichen. Ein Informationsbereich bietet neutrale Informationen über Risiken und Nutzen von klinischen Studien und einen Glossar mit Erklärungen von Fachwörtern, die auch der Laie versteht. www.probanden.info wurde in Abstimmung mit der Ethikkommission erstellt.
A novel algesic peptide derived from skin secretions of the frog Amolops loloensis
Authors: Yu Haining , Wang Xu , Liu Jingze , Lai Ren
Published: August 2007

Several algesic agents including bradykinin and tachykinin have been identified from skin secretions of amphibians. They may act in defensive roles against aggressors. In this study, a novel peptide named Amolos with an amino acid sequence of FLPIVGAKL and isolated from skin secretion of the frog Amolops loloensis, is shown to strengthen nociceptive responses induced by inflammatory factors and strongly inhibit the contraction of isolated ileum. A synthetic peptide based on the sequence obtained showed characterization data identical to those of the isolated material, confirming its structure. These two types of responses seem to be a part of the defensive functions against predators or aggressors. The current results suggest that pharmacological molecules in amphibian skins not only act as innate defense mechanisms against microorganisms but also exert other defensive physiological functions against other aggressors. Copyright © 2007 European Peptide Society and John Wiley & Sons, Ltd.
Soft shell resins for solid‐phase peptide synthesis
Authors: Lee Tae‐Kyung , Choi Jeong‐Hyun , Ryoo Sun‐Jong , Lee Yoon‐Sik
Published: August 2007

Soft shell (SS) resins with a lightly or noncross‐linked shell layer were prepared by reducing the amount of cross‐linking agent, divinylbenzene (DVB), during seed suspension polymerization from polystyrene (PS) resin. These SS resins have a lower swelling volume than that produced by normal cross‐linking. Despite its lower swelling, however, SS (10–00) resin, which consists of the 1% DVB‐cross‐linked core and the noncross‐linked surface layer, showed higher efficiency in peptide synthesis compared with 1% DVB‐PS resin and other SS resins. Copyright © 2007 European Peptide Society and John Wiley & Sons, Ltd.
Positional and geometrical isomerization during partial hydrogenation of trilinolein: A comparison of copper and nickel catalysts
Authors: Kirschner E. , Lowrey E. R.
Published: August 2007

We have compared a nickel with a copper catalyst in the formation of some geometrical and positional isomers during the partial hydrogenation of trilinolein. The copper catalyst was found to produce fewer diene isomers than the nickel catalyst at a comparable iodine value. The copper catalyst produced more monoene isomers however, than did the nickel, particularlytrans monoenes. The distribution of the monoene isomers appeared to obey an equilibrium relationship with each other, independent of both iodine value and reaction conditions. We have presented additional evidence to postulate that copper catalysts hydrogenate polyenoic acids by first conjugating the acids. The selectivity of copper catalysts for triene over diene is probably due to the greater ease of conjugation of the triene.
Dimer acid structures: Cyclic structures of clay catalyzed dimers of normal linoleic acid, 9‐cis, 12‐cis‐Octadecadienoic acid
Authors: Wheeler D. H. , Milun A. , Linn F.
Published: August 2007

The clay catalyzed dimer of linoleic acid has been examined by mass spectrometry of the unhydrogenated, the partially hydrogenated and completely hydrogenated dimer. The results show that monocyclic, bicyclic and tricyclic structures are present. Monocyclic structures predominate, bicyclic structures are also prominent, and tricyclic structures are relatively minor. The monocyclic structure is believed to arise from a Diels‐Alder type addition reaction. The bicyclic structure may result from a free radical coupling followed by intramolecular ring closure. The monocyclic structure in the unhydrogenated dimer appears to be mostly a benzene ring with saturated and unsaturated side‐chains. It probably is formed by hydrogen transfer from the Diels‐Alder cyclohexene structure first formed. Little, if any, of the Diels‐Alder dimer structure as such is present. The catalytic linoleate dimer has a higher ratio of monocyclic to bicyclic dimer than does the noncatalytic (thermal) dimer made from normal (nonconjugated) linoleate, while the thermal dimer of a conjugatedtrans‐trans linoleate is exclusively monocyclic. It is suggested that the clay catalyzes conjugation and hence favors the Diels‐Alder reaction, and then catalyzes hydrogen transfer to aromatize the cyclohexene ring.
Unsaturated lipid peroxidation catalyzed by hematin compounds and its inhibition by vitamin E1
Authors: Tappel A. L. , Brown W. Duane , Zalkin H. , Maier V. P.
Published: August 2007

Evidence favoring hematin catalysis over autoxidation as the dominant mechanism of lipid peroxidation in animal tissues is presented. Lipid peroxidation in Erlich ascites tumor cells and isolated electron transport particles has been studied. Random destruction of the cytochromes and a loss of catalytic activity correlate with peroxidation of the electron transport particle.

Mixtures of α‐, β‐, and γ‐tocopherols show no synergistic effect. Synergism with ascorbate and citrate greatly enhance the antioxidant activity of α‐tocopherol. A tocopherol‐ascorbate‐glutathione‐triphosphopyridine nucleotide couple could act synergistically to inhibit lipid peroxidation in animal tissues.
Yellowing of oil films
Authors: Privett O. S. , Blank M. L. , Covell J. B. , Lundberg W. O.
Published: August 2007

Results of studies of the effects of various factors on film yellowing, the mechanism of yellowing, its inhibition, and isolation and characterization of the yellow constituents are reported.

Yellowing appears to be a side reaction unrelated to the drying process, but colorless precursors of the yellow compounds are formed as a result of an oxidative process.

The formation of the yellow compound was postulated as taking place by the interreaction of the colorless precursors in some type of condensation. Low‐molecular‐weight aldehydes prevented yellowing, possibly by acting as substitutes for some reactant in the condensation reaction.
An accelerated test of the yellowing tendency of drying oils
Authors: Privett O. S. , Blank M. L. , Lundberg W. O.
Published: August 2007

An accelerated test for the determination of the yellowing tendency of oils is described.

The test is demonstrated on purified esters as well as on a number of commonm oils used as vehicles in paints and varnishes.
Cottonseed oil pigments: Fractionation by means of molecular sieves, countercurrent distribution, and low‐temperature crystallization
Authors: Verberg Gerald , McCall Elizabeth R. , O'Connor Robert T. , Dollear F. G.
Published: August 2007

Crude cottonseed oils were shown to have spectra of two types, those exhibiting a single maximum at about 360 mμ and those exhibiting a double maxima at about 375 and 400 mμ. Gossypol and cottonseed oil pigments which absorb below about 375 mμ are trapped by molecular sieve No. 13X, appear in the hydrophilic phase in countercurrent distribution of the oil between 95% ethanol and isooctane, and are found in the liquid fraction on crystallization of oil from acetone at −63°C. Those pigments not admitted by molecular sieve No. 13X are found in the hydrophobic phase in countercurrent distribution and in the solid fraction from low‐temperature crystallization. Only countercurrent distribution achieved separation of both types of pigments from the triglycerides. Insufficient quantities of pigments were isolated for any extensive characterization. Use of large‐scale apparatus would appear to make it possible to separate the pigments for characterization and evaluation of their relation to the refining properties of oils.
Surfactants for oil recovery
Authors: Ahearn G. P.
Published: August 2007

There is estimated to be about 250 billion barrels of oil in this country that are currently deemed economically unrecoverable. With conventional recovery techniques it is possible to recover about 47% of the estimated total oil in place, and steady improvement in technology may eventually bring crude oil recovery up to 65% of the oil in place. It is apparent that oil recovery is a relatively inefficient process. Therefore, in light of the increasing costs of finding and drilling for new oil, there is an enormous economic incentive to recover even a fraction of the vast amount of oil left behind in our existing reservoirs. Water injection has been the most successful additional recovery process developed in the last century. It is estimated that by 1975, 41% of the nation’s crude output will be recovered by this technique. For years the idea of developing a chemical that could be added to the injected water to increase ultimate oil recovery has intrigued the entire industry. This paper deals with recent attempts by the industry to develop surfactants to recover the oil that remains after conventional recovery operations. The requirements for developing an effective surfactant are discussed in detail and the chemist’s role in assisting in this development is highlighted.
Evaluation of enzymes for laundry products
Authors: Cayle Theodore
Published: August 2007

Currently the two classes of enzymes finding favor as detergent additives are the proteases and amylases. Data are presented showing some of the desirable characteristics such enzymes must possess to be successfully employed as laundry products. Whereas it is easy to determine the activity of the enzymes with test tube assays using homogeneous substrates, translation to a practical method for laboratory evaluation in which apparent laundering ability is correlated with enzyme content has proved to be more difficult. Data are presented showing that, whereas EMPA 116 test fabric (uniformly stained with blood, milk and Japanese ink) is suitable for establishing the effectiveness of detergents containing proteases, the commonly employed EMPA 112 (stained with cocoa, milk and sugar) used for evaluating amylase‐containing products is a poor choice for this purpose. This appears to be because both cocoa and milk contain proteins serving to bind the stains to the cloth. Accordingly, EMPA 112 responds to protease as well as amylase. An experimental test fabric, uniformly stained with starch and lampblack, has been prepared and has proved to respond solely to the amylase present in detergent formulations. Thus, it is now possible to evaluate the effectiveness of the amylase component in laundry products, independent of the influence of other enzyme systems that might also be present.
Development of screening tests for hard surface cleaners: I. Artificial soil removal from linoleum surfaces
Authors: Adler R. R. , Albin T. B. , Finger B. M.
Published: August 2007

A quantitative method for evaluating performance of hard surface cleaners has been developed based on a series of modifications of previously proposed tests. The principle involves the mechanical cleaning of artificially soiled linoleum with a Gardner Straight Line Washability Machine. A quantitative estimation of the relative cleaning efficiency is determined photometrically and results are expressed as per cent return to original whiteness. Statistical evaluations have shown the method to be reproducible and applicable for discerning differences in formulations, concentration and surfactant structure. The test method details are described and experimental results showing ethylene oxide content optimization of commercial linear primary alcohol‐based nonionics, as well as builder effects, are presented.
Dietary fat composition and tocopherol requirement: I. Lack of correlation between nutritional indices and results of in vitro peroxide hemolysis tests
Authors: Alfin‐Slater R. B. , Hansen H. , Morris R. S. , Melnick D.
Published: August 2007

In general, the native tocopherols in polyunsaturated vegetable oils such as cottonseed oil, corn oil and their lightly hydrogenated products include sufficient vitamin E for growth, reproduction, lactation and normal lipid metabolism in the rat. The administration of vitamin E to animals fed diets deficient in essential fatty acids (e.g., a hydrogenated coconut oil or a fat‐free diet) does not stimulate growth or reproductive performance per se, although testes development in the male rats is improved and some improvement in lipid metabolism is also noted. Hemolysis of the erythrocytes in vitro by hydrogen peroxide is increased in animals on diets rich (30%) in polyunsaturated vegetable oils or on diets providing no essential fatty acids at all. However, the conditions of the in vitro hemolysis test are not related to those in vivo and the in vitro test is not a measure of erythrocyte fragility. In addition, the in vitro hemolysis test does not necessarily reflect plasma tocopherol levels nor an abnormal nutritional state as a result of subsistence on high linoleate, low tocopherol intake, but rather measures the susceptibility to oxidation of a labile biological substrate and indicates the effective balance between potentially oxidizable lipids (polyunsaturates) in the stroma of the red blood cell and the antioxidant present (tocopherol or vitamin E). The labile lipid substrate may be either of exogenous origin (diet) or may be formed endogenously through tissue synthesis (as a result of an essential fatty acid deficiency). It is concluded that the in vitro hemolysis test may not be a valid indicator of vitamin E nutriture unless it is used in conjunction with other nutritional tests.