bluuebunny/crossref_metadata_2025_split huggingface dataset:
Concurrent formation of five and eight‐membered heterocyclic methylphosphonates in cyclization reactions from diethyleneglycole
Authors: Moghimi Abolghasem , Rafiei Javad , Baghaie Parvin , Aghabeygi Shokoofeh , Moosavi S. Mojtaba 
Published: August 2009

Abstract
magnified imageTwo methodologies have been investigated for the preparation of heterocyclic methylphosphonate using diethyleneglycole and either MPDC or DMMP as the bifunctional group starting materials needed for cyclization reactions. In addition to the eight‐membered ring methylphosphonate I the five‐membered ring methylphosphonate II was unexpectedly found to be formed during the cyclization reactions. This small‐size cyclic methylphosphonate may have been generated from an intramolecular cyclization reaction by the nucleophilic attack of the ether oxygen atom of the intermediate MeP(O)(X)OCH2CH2OCH2CH2OH (X = Cl or OMe). The resulting cyclic phosphonates were purified and characterized by NMR and mass spectroscopy. J. Heterocyclic Chem., (2009).
Utility of p‐phenylenediformamidine in the synthesis of bisazoles and phenanthroline
Authors: Al‐Mousawi Saleh M. , Elassar Abdel‐Zaher A. 
Published: August 2009

Abstract
magnified imagep‐Phenylenediformamidine 1 is readily obtained upon treating p‐phenylenediamine with dimethylformamide dimethyl acetal (DMFDMA) by heating or by microwave irradiation. Compound 1 was treated with active methylene nitriles followed by hydrazine hydrate derivatives to give bisaminopyrazole derivatives. Other bisazoles can be obtained by reacting 1 with aminoazole derivatives. Cyclization of Bis [2‐(p‐phenelyeneimino)malononitrile] to 1,10‐diaminophenanthroline‐2,9‐dicarbonitrile is also reported. J. Heterocyclic Chem., (2009).
Reinvestigation of alternative method for the preparation of dibenz[b,f][1,4]oxazepine
Authors: Fakhraian Hossein , Nafary Yaser 
Published: August 2009

Abstract
magnified imageTwo distinct alternative methods using different starting materials for the preparation of dibenz[b,f][1, 4]oxazepine (7, CR) were reinvestigated. The possibility of trans‐cis conversion of the Schiff base 5cis, 5trans (produced from 1 and 2) is considered the favorable orientation that leads to cyclization (production of 7). Fluoro derivative of 1 afforded excellent and more convenient conditions for the one pot preparation of high yield pure 7. The presence of only trans configuration for the imine 6cis, 6trans (produced from 3 with 4) and the impossibility of its conversion to cis, makes it inadequate for the preparation of 7. J. Heterocyclic Chem., (2009).
Fiber‐type distribution of the perivertebral musculature in Ambystoma
Authors: Schilling Nadja , Deban Stephen M. 
Published: August 2009

AbstractMany salamanders locomote in aquatic and terrestrial environments. During swimming, body propulsion is solely produced by the axial musculature generating lateral undulations of the trunk and tail. During terrestrial locomotion, the trunk is oscillated laterally in a standing wave, and body propulsion is achieved by concerted trunk and limb muscle action. The goal of this study was to increase our knowledge of the functional morphology of the tetrapod trunk. We investigated the muscle‐fiber‐type distribution and the anatomical cross‐sectional area of all perivertebral muscles in Ambystoma tigrinum and A. maculatum. Muscle‐fiber‐type composition was determined in serial cross‐sections based on m‐ATPase activity. Five different body segments were investigated to test for cranio‐caudal changes along the trunk. The overall fiber‐type distribution was very similar between the species, but A. tigrinum had relatively larger muscles than A. maculatum, which may be related to its digging behavior. None of the perivertebral muscles possessed a homogeneous fiber‐type composition. The M. interspinalis showed a distinct layered organization and may function to ensure the integrity of the spine (local stabilization). The M. dorsalis trunci exhibited the plesiomorphic pattern for notochordates in having a distinct superficial layer of red and intermediate fibers, which covered the central white fibers; therefore, it is suggested to function as a mobilizer and a stabilizer of the trunk, but, may also be involved in modulating body stiffness. Similarly, the M. subvertebralis showed clear regionalizations, implying functional subunits that can stabilize and mobilize the trunk as well as modulate of body stiffness. Cranio‐caudally, neither the fiber‐type composition nor the a‐csa changed dramatically, possibly reflecting the need to perform well in both aquatic and terrestrial habitats. J. Morphol., 2010. © 2009 Wiley‐Liss, Inc.
Feasibility of diffusion‐weighted MRI for defining placental invasion
Authors: Morita Satoru , Ueno Eiko , Fujimura Mikihiko , Muraoka Mitsue , Takagi Koichiro , Fujibayashi Mariko 
Published: August 2009

AbstractThe purpose of this clinical note is to describe the feasibility of using diffusion‐weighted imaging for diagnosing placental invasion with a case of placenta increta and six cases without it. Diffusion‐weighted imaging (DWI) at a b‐value of 1000 sec/mm2 can clearly define the border between the placenta and myometrium because only the placenta shows very high signal intensity. The corresponding image at a b‐value of 0 sec/mm2 shows the myometrium with high signal intensity compared with the surrounding fat. Therefore, fusion of the two images can be used additionally to visualize thickness of the myometrium. As a result, DWI can be used to visualize the focal thinning of the myometrium caused by placenta increta, which has been difficult to diagnose on conventional magnetic resonance imaging sequences without contrast enhancement. However, the use of DWI for placental invasion should be determined following careful consideration of its risks and benefits, as fetus safety has not been established. J. Magn. Reson. Imaging 2009;30:666–671. © 2009 Wiley‐Liss, Inc.
Texture analysis of magnetization transfer maps from patients with clinically isolated syndrome and multiple sclerosis
Authors: Tozer D.J. , Marongiu G. , Swanton J.K. , Thompson A.J. , Miller D.H. 
Published: August 2009

AbstractPurposeTo investigate the behavior of texture parameters derived from the gray level co‐occurrence matrix from gray matter (GM) and white matter (WM) (with lesions removed) segments of magnetization transfer ratio maps from controls and patients.Materials and MethodsMagnetization transfer ratio maps from 23 controls and patients with either a clinically isolated syndrome (CIS) (38 patients) or clinically definite multiple sclerosis (MS) (35) were scanned and texture parameters extracted. The texture parameters were compared between the groups and correlated with clinical measures of disability in the MS patients to investigate any association with disease severity.ResultsNo significant differences were found between the texture parameters from controls and CIS patients; however, several parameters differ between MS patients and the two other groups, particularly in the GM, but also in the WM. The expanded disability status score and timed walk test correlate with GM texture measures, while the Paced Auditory Serial Addition Test 3 score, a cognitive measure, correlates with WM texture. Texture abnormalities were seen in MS WM and GM, indicating tissue damage beyond classical WM lesions, the abnormalities being more evident in GM.ConclusionThe findings highlight potential for texture analysis measures in classifying central nervous system demyelinating diseases that warrants further investigation. J. Magn. Reson. Imaging 2009;30:506–513. © 2009 Wiley‐Liss, Inc.
Structure and antioxidant activity of brominated flavonols and flavanones
Authors: Justino Gonçalo C. , Rodrigues Margarida , Florêncio M. Helena , Mira Lurdes 
Published: August 2009

AbstractHypobromous acid (HOBr) produced by both eosinophil peroxidase (EPO) and myeloperoxidase (MPO) is a stronger oxidant than HOCl, and is also essential for optimal and efficient microbial killing. Considering the potential cytotoxic effect of HOBr, if it is formed outside the phagosome, it should be useful to scavenge it in order to protect the nearby tissues. In this study the ability of selected flavonoids to protect against HOBr mediated oxidation reactions was performed through a competitive reaction, and the resulting products identified by high performance liquid chromatography (HPLC) and electrospray ionization tandem mass spectrometry(ESI‐MS/MS). Several structural features were found to be important to confer high antioxidant activity to flavonoids towards HOBr: the C2C3 double bond and the 3OH group in the C‐ring, and the presence of both 5OH and 7OH groups in the A‐ring. The MS results showed that flavonoids are dibrominated in the A‐ring, suggesting that (except for fisetin) bromination occurs at C6 and C8 positions, through an electrophilic aromatic substitution reaction. The chemical modifications achieved by bromination of flavonoids have changed their biological properties, presenting their brominated derivatives higher antioxidant activity, as radical scavengers, and higher lipophilicity, than the parent flavonoids. Brominated flavonoids may then diffuse easily through membranes increasing the intracellular concentration of the compounds. These locally formed metabolites may also interact with signaling cascades involving cytokines and regulatory transcription factors, thus playing a role in inflammation and in the regulation of immune response. Copyright © 2009 John Wiley & Sons, Ltd.
Extent and deglacial chronology of the last British–Irish Ice Sheet: implications of exposure dating using cosmogenic isotopes
Authors: Ballantyne Colin K. 
Published: August 2009

AbstractOver 160 10Be and 36Cl exposure ages pertaining to the extent and chronology of the last British–Irish Ice Sheet (BIIS) are critically reviewed. Despite uncertainties inherent in the use of exposure ages, this approach has demonstrated that at the Last Glacial Maximum (LGM; ca. 26–21 ka) the BIIS extended over all low ground in Scotland and all (or almost all) of Ireland, consistent with recent models depicting extension of the last BIIS to the Atlantic shelf edge. All exposure ages obtained for high‐level sites above trimlines on the mountains of northwestern Scotland and Ireland pre‐date the LGM. This finding confirms that high plateaux in these areas escaped significant glacial erosion, probably under a protective cover of cold‐based glacier ice that remained frozen to the underlying substrate. In terms of deglaciation chronology, the southern Irish Sea basin was probably deglaciated by 19–18 ka, with extensive deglaciation of low ground in Ireland and northeastern Scotland prior to ca. 14.5 ka. Ice cover on low ground in northwestern Scotland apparently persisted after 14.0 ka, suggesting survival of ice in favourable locations during the Lateglacial Interstade (ca. 14.5–12.9 ka). Attempts to date readvances have had mixed success. The Wester Ross Readvance in northwestern Scotland was initially dated to ca. 16.3 ka, but more recent research implies a much younger age (ca. 14.0–13.5 ka). Exposure ages indicating a prolonged stillstand during ice sheet retreat in the Cairngorms at ca. 14.5–14.0 ka conflict with ages obtained on postglacial rockslides and basal radiocarbon dates, which indicate deglaciation before ca. 15.5–15.0 ka. Exposure dating has been successfully employed to confirm a Loch Lomond Stadial (ca. 12.9–11.5 ka) age for moraines in several mountain areas, and to constrain the minimum altitude of the ice cap that extended over the Western Grampians at that time. Copyright © 2009 John Wiley & Sons, Ltd.
Visible laser–induced photoreduction of silver 4‐nitrobenzenethiolate revealed by Raman scattering spectroscopy
Authors: Kim Kwan , Lee Yoon Mi , Lee Hyang Bong , Park Yeonju , Bae Tae Yeol , Jung Young Mee , Choi Cheol Ho , Shin Kuan Soo 
Published: August 2009

AbstractWe have investigated the photochemical characteristics of silver 4‐nitrobenzenethiolate (Ag‐4NBT) by means of Raman spectroscopy. When Ag‐4NBT is irradiated with an argon ion laser at 514.5 nm, its Raman spectrum changes over time, resulting in the production of 4NBT‐capped silver nanoparticles. The surface‐enhanced Raman scattering (SERS) spectrum of 4NBT adsorbed on those Ag nanoparticles is subsequently converted to that of 4‐aminobenzenethiol (4ABT). These surface‐induced photoreduction characteristics were investigated by monitoring the growth of Raman peaks of 4ABT as a function of the laser exposure time. Water vapor or ambient conditions were more effective than vacuum conditions for the photoreduction of 4NBT to 4ABT. Nonetheless, the occurrence of photolysis even under vacuum conditions suggests that the benzene ring hydrogen atoms might be the H‐atom source of the nitro‐to‐amine group conversion although in ambient conditions water or solvent molecules trapped inside the Ag‐4NBT should be the primary H‐atom source and facilitate the transfer of electrons, as well as the diffusion of Ag atoms to form highly SERS‐active nanoaggregates. Copyright © 2009 John Wiley & Sons, Ltd.
Fiber‐optic distributed sensor based on a Sagnac interferometer with a time delay loop for detecting time‐varying disturbance
Authors: Xu Wenyuan , Zhang Chunxi , Liang Sheng , Li Lijing , Lin Wentai , Yang Yusheng 
Published: August 2009

AbstractA fiber optic distributed sensor, based on a Sagnac interferometer for determining the location of time‐varying disturbance, is presented in this paper. The proposed distributed sensor constitutes a Sagnac interferometer with an additional time delay fiber loop. Due to the time‐division multiplexing technique, by employing the light pulse, there are actually two Sagnac interferometers utilized for distributed sensing, and the amplitudes of the time‐division multiplexed signals are distinguished and converted to location information. Experimental results obtained with a 10 km long sensing fiber are discussed. The proposed distributed sensor has the advantages of capability of real time sensing, low cost and simple configuration. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2564–2567, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24672
An efficient analysis of frequency selective surface in spectral domain with RWG basis functions
Authors: Zhuang Wei , Chen Riu S. , Ding Dazhi Z. , Wang Daoxiang X. 
Published: August 2009

AbstractIn this article, the spectral domain method of moment is utilized to analyze frequency selective surface with RWG basis functions for arbitrarily shaped metal geometry. The Fourier transform of the RWG basis function can be expressed in the analytical form and the fast convergence characteristic can reduce the computation time of impedance matrix. Some examples are calculated to demonstrate the efficiency of the proposed method. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2567–2570, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24674
Design of square microstrip antenna for dual wideband operation
Authors: Singh Kishan , Konda R. B. , Sameena N. M. , Mulgi S. N. 
Published: August 2009

AbstractA novel design of square microstrip antenna is designed for dual band operation. By embedding unequal length inverted right angle slot at optimum place on the square patch, the upper operating band enhanced from 27.53 to 60.01% with minimum change in the lower operating band retaining the nature of broad side radiation characteristics. The proposed antennas may find application in radar communication. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2578–2582, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24678
Design of multilayer triangular substrate integrated waveguide filter in LTCC
Authors: Shen Wei , Sun Xiao‐Wei , Yin Wen‐Yan , Mao Jun‐Fa , Wei Qi‐Fu 
Published: August 2009

AbstractThis article proposes a four‐pole quasi‐elliptic function triangular substrate integrated waveguide bandpass filter, which was fabricated using multilayer low‐temperature cofired ceramic technology. In our design, neural network inverse model is adopted to fast capture the sizes of TSIW cavities, with the coupling matrix transformation implemented to achieve cross coupling on the basis of multilayer TSIW. A slot on the top metal layer is introduced so as to suppress the two higher spurious modes. The filter has 65% size reduction in comparison with its planar counterpart, with good agreement obtained between the simulated and measured S‐parameters. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2582–2585, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24680
Ku‐band substrate integrated waveguide transitions between layers
Authors: Song Kaijun , Fan Yong 
Published: August 2009

AbstractTwo types of the substrate integrated waveguide (SIW) transitions between layers are presented in this letter. The SIW circuits have been used to achieve the transition from one layer to other layer. These two types of SIW transitions between layers operating in Ku‐band have been designed and fabricated. The measured 10‐dB return loss bandwidth of the transition between adjacent layers is about 7 GHz, and the measured 1‐dB insertion loss bandwidth is about 5 GHz; the measured 13‐dB return loss bandwidth of the unadjacent‐layers transition is demonstrated to be about 3.7 GHz, and the measured insertion losses are less than 2 dB from 11.2 GHz to 15 GHz. The simulated and measured results indicate that these two SIW transitions take the advantages of broadband, low insertion loss, and low profile. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2585–2588, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24685
Analysis of the human body on the radiation of FM handset antenna
Authors: Vergés Jordi , Anguera Jaume , Puente Carles , Aguilar David 
Published: August 2009

AbstractA simple human body phantom model is proposed and used to demonstrate that the radiation efficiency of an internal handset antenna operating at the FM band can be improved for a particular holding position up to 10 dB. To corroborate the numerical results, an experiment using a real human body has been performed showing very good agreement. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2588–2590, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24686
Compact and ultra wideband printed eliptical monopole antenna with modified‐shape ground plane
Authors: Karimabadi S. S. , Attari A. R. 
Published: August 2009

AbstractA novel compact and ultra wideband antenna with a printed monopole structure is presented in this article. It is demonstrated that with a modified‐shape ground plane, an ultra wide bandwidth can be achieved with small radiation element size. Simulation and measurement results show that the antenna impedance bandwidth covers the frequency range of 3.1–10.6 GHz. Performance of the proposed antenna is examined in terms of return loss, radiation pattern, transfer function and received signal waveform. It is shown that the proposed antenna has almost omni‐directional radiation pattern over the whole band. To evaluate the capability of antenna in preserving the waveform of source pulse the fidelity factor is calculated. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2604–2607, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24689
Quadrifilar helical antenna design for satellite‐mobile handsets using genetic algorithms
Authors: Zhou D. , Abd‐Alhameed R. A. , See C. H , Excell P. S. , Hu Y. F. , Khalil K. , McEwan N. J. 
Published: August 2009

AbstractA circularly polarized quadrifilar helical antenna, operated at 2.4 GHz and intended for applications in satellite mobile communications, is designed using genetic algorithms (GA). The antenna was firstly considered as a test on an infinite ground plane and then optimized further on small size handsets. The performance of the optimized antenna design was analyzed using commercial simulators in terms of impedance match, axial ratio, and gain. Results for the optimal antenna met the design objectives subject to certain parametric constraints. The design shows the capabilities of GA as an efficient optimization tool for selecting globally optimal parameters to be used in simulations with an electromagnetic antenna design code, seeking convergence to specific design specifications. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2668–2671, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24694
Coplanar waveguide fed taper arc slot antenna for microwave imaging and ultra wide band applications
Authors: Hossain I. , Noghanian S. , Shafai L. , Pistorius S. 
Published: August 2009

AbstractDesign features of a reduced size coplanar waveguide (CPW) fed ultra wide band (UWB) taper arc wide slot antenna with impedance Band Width (BW) of 9.69 GHz have been illustrated. The antenna depicts satisfactory performance both on free space and when immersed in three different coupling materials for application in the experimental MI set up. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2607–2611, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24701
A 1.5‐V transformer‐based ultra‐wideband LNA chip design
Authors: Huang Jhin‐Fang , Shie Pei‐Jiuan , Liu Ron‐Yi 
Published: August 2009

AbstractIn this article, a low‐noise amplifier (LNA) for ultra‐wideband (UWB) systems operating at 3–5 GHz frequency range is presented. The proposed LNA uses an on‐chip transformer to achieve the realization of a wideband input‐integrated matching to the antenna impedance, as well as the cascode amplifier with shunt peaking can provide a high power gain. The transformer‐based LNA fabricated in a TSMC 0.18‐μm CMOS process with 1.5 V supply voltage achieves a maximum power gain of 19.2 dB in addition to the minimum noise figure (NF) of 3.5 dB, an input return loss (S11) smaller than −9.3 dB over the whole frequency range. This circuit also present an input‐referred third‐order intercept point (IIP3) of −11 dBm at 5 GHz and an input‐referred 1 dB compression point of −21 dBm at 5 GHz. The chip area including pads is only 0.8 mm2 and power dissipation is 13.5 mW. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2649–2652, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24705
Metamaterial‐based phased array for directional beam steering
Authors: Ourir Abdelwaheb , de Lustrac A. 
Published: August 2009

AbstractUltracompact metamaterial‐based cavity (thickness λ/15) is proposed to realize a low secondary lobes level and highly directive phased array antenna. The cavity is fed by an array of four patch antennas designed to operate at around 9.5 GHz. The radiation patterns of the phased arrays are compared with those of their respective metamaterial‐based cavity antennas. The latter structures have lower secondary lobes and provide higher gain and directivity. Moreover, the cavities enhance the beam steering of the phased arrays. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2653–2656, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24709