bluuebunny/crossref_metadata_2025_split huggingface dataset:
Semipreparative chiral supercritical fluid chromatography in the fractionation of lansoprazole and two related antiulcer drugs enantiomers
Authors: Toribio Laura , del Nozal María J. , Bernal Yagüe L. , Alonso Cristina , Jiménez Juan J. 
Published: March 2008

AbstractThe semipreparative chiral separation of lansoprazole and two related compounds (pantoprazole and rabeprazole) using supercritical fluid chromatography (SFC) is presented in this work. Different loads were evaluated in order to obtain high enantiomeric purities and production rates. The volumes injected were 1, 2 and 4 mL. The concentrations of the racemic mixtures were 3 and 6 g/L for lansoprazole and 1.5 g/L for pantoprazole and rabeprazole. In all the cases, the recoveries, for a purity higher than 99.9%, were better for the second eluted enantiomer than for the first one. This fact conditioned the production rate of the first eluted enantiomer that, considering a fixed purity, was always lower than that obtained for the other one. In the case of lansoprazole it was possible to obtain 0.025 and 0.090 mg/min of the first and second eluted enantiomer, respectively, with an enantiomeric purity of 99.9%. For rabeprazole enantiomers 0.037 and 0.062 mg/min, and in the case of pantoprazole the results were better (0.062 and 0.122 mg/min) due to the higher resolution.
Extraction of carotenoids and chlorophyll from microalgae with supercritical carbon dioxide and ethanol as cosolvent
Authors: Macías‐Sánchez Ma Dolores , Mantell Serrano Casimiro , Rodríguez Rodríguez Miguel , Martínez de la Ossa Enrique , Lubián Luís M. , Montero Olimpio 
Published: March 2008

AbstractThe extraction of carotenoids and chlorophylls using carbon dioxide modified with ethanol as a cosolvent is an alternative to solvent extraction because it provides a high‐speed extraction process. In the study described here, carotenoid and chlorophyll extraction with supercritical CO2 + ethanol was explored using freeze‐dried powders of three microalgae (Nannochloropsis gaditana, Synechococcus sp. and Dunaliella salina) as the raw materials. The operation conditions were as follows: pressures of 200, 300, 400 and 500 bar, temperatures of 40, 50 and 60°C. Analysis of the extracts was performed by measuring the absorbance and by using empirical correlations. The results demonstrate that it is necessary to work at a temperature of 50–60°C and a pressure range of 300–500 bar, depending on the type of microalgae, in order to obtain the highest yield of pigments. The best carotenoid/chlorophyll ratios were obtained by using supercritical fluid extraction + cosolvent instead of using conventional extraction. The higher selectivity of the former process should facilitate the separation and purification of the two extracted pigments.
Organ pipes and tin pest
Authors: Eckert A. 
Published: March 2008

AbstractThis article introduces various aspects of a diploma thesis on the theme of ‘tin pest in organ pipes’ submitted to the Fachhochschule in Cologne. One aspect concerns the difference between corrosion and tin pest in organ pipes, another explains the polymorphous property of tin. This is followed by a report on the research and documentation on 12 suspected cases of tin pest. A case of tin pest in an alloy of tin and lead in an Estonian organ receives particular attention, not least because hitherto it has often been assumed that tin pest could only occur in pure tin. Finally, the necessary conditions for an occurrence of tin pest are discussed as well as recommendations on treating organ pipes which have been damaged by tin pest.
Ring‐Opening Metathesis Polymerization of Amino Acid‐Functionalized Norbornene Diamide Monomers: Polymerization Behavior and Chiral Recognition Ability of the Polymers
Authors: Sutthasupa Sutthira , Sanda Fumio , Masuda Toshio 
Published: March 2008

AbstractAmino acid‐derived novel norbornene monomers were synthesized and polymerized with ruthenium catalysts. The polymerization rates were affected by the stereo structure of the monomers; exo,exo‐NBL underwent ROMP faster to give the polymers in higher yields than the endo,exo‐counterpart. The Grubbs 2nd generation catalyst was the most effective for the amino acid‐based monomers. A polymer gel was synthesized by the copolymerization of exo,exo‐NBL with 2.5 mol‐% of bifunctional norbornene monomer. The gel adsorbed larger amounts of (R)‐phenylalaninol and N‐(benzyloxycarbonyl)alanine than those of the (S)‐isomers.magnified image
The Effect of PEG Crystallization on the Morphology of PEG/Peptide Block Copolymers Containing Amyloid β‐Peptide Fragments
Authors: Krysmann Marta J. , Funari Sérgio S. , Canetta Elisabetta , Hamley Ian W. 
Published: March 2008

AbstractOrdered nanostructures are observed in the melt and solid state for a series of three peptide/PEG conjugates containing fragments of amyloid β‐peptides. These are conjugated to PEG with $\overline M _{\rm n}$ = 3 300 g · mol−1 and a melting temperature Tm = 45–50 °C. The morphology at room temperature is examined by AFM and POM. This shows spherulite formation for the weakly fibrillizing KLVFF‐PEG sample but fibril formation for FFKLVFF‐PEG. The fibrillization tendency of the latter is enhanced by multiple phenylalanine residues. Simultaneous SAXS and WAXS was used to investigate the morphology as a function of temperature. The secondary structure is probed by FTIR.magnified image
Engineering Polymer Informatics: Towards the Computer‐Aided Design of Polymers
Authors: Adams Nico , Murray‐Rust Peter 
Published: March 2008

AbstractThe computer‐aided design of polymers is one of the holy grails of modern chemical informatics and of significant interest for a number of communities in polymer science. This paper outlines a vision for the in silico design of polymers and presents an information model based on modern semantic web technologies, thus laying the foundations for achieving the vision.magnified image
Intramolecular Click Cycloaddition: An Efficient Room‐Temperature Route towards Bioconjugable Polymeric Nanoparticles
Authors: de Luzuriaga Alaitz Ruiz , Ormategui Nerea , Grande Hans J. , Odriozola Ibon , Pomposo José A. , Loinaz Iraida 
Published: March 2008

AbstractA highly efficient room‐temperature synthetic route to bioconjugable polymeric nanoparticles in the 5–20 nm size range based on single‐chain intramolecular click cycloaddition is described. It is illustrated by preparing single‐chain cross‐linked polymeric NPs from poly[MMA‐co‐(3‐azidopropyl methacrylate)‐co‐(3‐trimethylsilyl‐propyn‐1‐yl methacrylate)] terpolymers using a one‐pot procedure and a continuous addition technique. For polymeric NPs with an excess of azide groups, aminoacid/PMMA NPs were easily obtained by performing a second click reaction with propargyl glycine. This versatile and general method opens the way to the synthesis of other kinds of polymeric and bioconjugated NPs beyond those reported in this communication.magnified image
Synthesis of Near‐Infrared Responsive Gold Nanorod/PNIPAAm Core/Shell Nanohybrids via Surface Initiated ATRP for Smart Drug Delivery
Authors: Wei Qingshan , Ji Jian , Shen Jiacong 
Published: March 2008

AbstractNanosized near infrared (NIR) responsive nanohybrids are synthesized by surface‐initiated atom transfer radical polymerization (SI‐ATRP) of N‐isopropylacrylamide (NIPAAm) on gold nanorods (Au NRs). Transmission electron microscopy images demonstrate that the nanohybrids have a clear core/shell structure. Temperature‐variable 1H NMR spectroscopy, quasi‐elastic light scattering (QELS), UV‐vis spectroscopy, and laser irradiation prove that the nanohybrids are both temperature and NIR responsive. Norvancomycin (NVan) loading and release experiments show that the drug release rate can be modulated by NIR irradiation. Such an intelligent drug‐delivery system might find applications in non‐invasive controlled drug release in future.magnified image
Poly(phenylethylnorbornene)s and their Hydrogenated Derivatives
Authors: Bishop John P. , Register Richard A. 
Published: March 2008

AbstractRing‐opening metathesis polymerization (ROMP) was used to synthesize novel ring‐opened poly[5‐(2‐phenylethylnorbornene)]. Hydrogenation can produce two different saturated derivatives, with the phenyl groups either preserved or saturated to cyclohexyl groups. These two different hydrogenated products allowed us to compare the effect of replacing the pendant phenyl groups with cyclohexyl groups on properties such as the glass transition temperature (Tg). We found that Tg decreased by only 2 °C (from 28 to 26 °C) upon replacement of the phenyl groups. This contrasts with the effect of saturating the phenyl groups in the addition polymer of 5‐(2‐phenylethylnorbornene), where the Tg increased by 34 °C, from 215 to 249 °C, a remarkable difference in magnitude and direction compared with the ROMP polymers.magnified image
Triband branch line coupler using double‐Lorentz transmission lines
Authors: Lee Hanseung , Nam Sangwook 
Published: March 2008

AbstractThe concept of double‐Lorentz (DL) transmission lines (TL) provides two additional degrees of freedom in realizing triband microwave devices. The triband operation is accomplished by the flexible phase slope characteristic of the DL TL with the frequency. In this article, the theory, design procedure, and implementation of the triband quarter‐wave (λ/4) DL TL are presented. Moreover, the triband λ/4 open‐circuit stub and triband branch‐line coupler (BLC) are introduced for the application of mobile TV service. The simulated and measured results of these triband components are also presented. The λ/4 DL TL open‐circuit stub demonstrates insertion loss larger than 17 dB at each target band. The triband BLC has S‐parameters of output larger than −4.569 dB, return losses larger than 14 dB, isolations larger than 15 dB, phase differences of output 90° ± 5° at each target band. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1174–1177, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23311
Segmented analysis of a finite planar ridged tapered slot antenna array for wideband phased array
Authors: Kim Junyeon , So Joonho , Jang Won , Cheon Changyul 
Published: March 2008

AbstractThe segmented analysis method of a finite planar ridged tapered slot antenna (RTSA) array is presented to develop a wideband phased array with a triangular lattice. The RTSA array is segmented into two‐parts with a feeder and the arrays of tapered slot antenna (TSA) and these scattering parameters are analyzed respectively. This proposed method gives the merit of a great reduction of computational cost. To verify the advantage of this method, we build the numerical model of only one feeder and dual polarized arrays of TSA with 10 × 12 elements. The measured results of the fabricated array meet the design goals of 3:1 bandwidth, scan volume of ±45°, active VSWR (AVSWR) below 3:1. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1140–1143, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23314
Miniaturized quadrature hybrid coupler using high impedance lines
Authors: Mandal Mrinal Kanti , Velidi Vamsi Krishna , Bhattacharya Amitabha , Sanyal Subrata 
Published: March 2008

AbstractIn this article, a new configuration has been proposed for miniaturization of a branch‐line 90° hybrid coupler. The present coupler is obtained by replacing the low impedance series arms of a conventional coupler by their equivalent parallel high impedance lines. This arrangement facilitates meandering, used to realize a compact geometry. The main advantage of the proposed coupler is that it has approximately the same bandwidth as that of a conventional one. A prototype coupler area is 45.3% of that of a conventional branch‐line coupler. The design is validated by full‐wave electromagnetic simulation and measurement. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1135–1137, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23320
New bandwidth enhancement and multiresonance technique for microstrip patch antenna
Authors: Kumar Patra Pradyumna , Pattnaik S. S. , Devi Swapna , Vidyasagar Ch. , Sastry G. V. R. S. , Bakward K. M. 
Published: March 2008

AbstractThe quality factor, bandwidth, and efficiency are antenna's figures of merit and these are interrelated. There is no typical method that gives full freedom to optimize these independently. Here we proposed a novel and new method to optimize bandwidth with respect to radiation quality factor Qr. Slicing a substrate into two thin layers substrate, an impedance bandwidth of 12% is achieved while reducing the volume by 44.5%. The technique proposed shows that instead of single thick substrate, if two thin substrates are used, an enhancement of impedance bandwidth takes place while maintaining high antenna gain and radiation efficiency. This is a new and novel technique for bandwidth enhancement in microstrip patch antenna and is quite different from stacked antenna. In this article, we sliced a substrate into two thin substrates each of 1‐mm thick to achieve a bandwidth of 12% and radiation efficiency of 80.5549 with an overall volume reduction of 44.5%. While a single substrate of thickness 2.5 mm which is more than the total thickness of the discussed structure gives only 5% bandwidth for same antenna dimensions. The proposed structure will find potential application in MIMO antenna system due to its volume reduction and other enhanced features. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1162–1165, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23323
A second‐order dual‐band bandpass filter using a dual‐band admittance inverter
Authors: Zhang Hualiang , Chen Kevin J. 
Published: March 2008

AbstractIn this article, a second‐order dual‐band bandpass filter is designed. The filter consists of two dual‐band resonators connected by a dual‐band admittance inverter. The dual‐band resonator unit is made of two shunt stubs that coordinately produce two resonances. A novel dual‐band quarter‐wavelength line acts as the admittance inverter, providing suitable admittance transformations. To verify the design concept, a filter working at 2 and 5 GHz is devised and fabricated on Rogers' RO3006 printed circuit boards. In addition, the dual‐band filter is connected with a bandstop filter to suppress the unwanted spurious response. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1184–1187, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23326
Bandpass multitap microwave photonic filter with a round‐trip configuration
Authors: Ning G. , Shum P. , Aditya S. , Cheng Linghao , Dong H. 
Published: March 2008

AbstractWe propose a novel bandpass microwave photonic multitap filter configuration using a section of Hi‐Bi fiber in a round‐trip configuration. The configuration makes use of a chirped FBG both as a mirror and a dispersive device. Measured results are presented to show a two‐tap and three‐tap filter response, with a notch rejection greater than 35 dB and tunability of the level of secondary sidelobes by adjusting a polarization controller. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1181–1184, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23330
Reconstruction of the shape and location of arbitrary homogeneous objects using sequentially incidences
Authors: Khalaj‐Amirhosseini M. , Hodjat‐Kashani F. , Kamarei M. 
Published: March 2008

AbstractIn this study, a new approach is introduced to reconstruct the location and shape of arbitrary homogeneous scatterers (conductors and lossy or lossless dielectrics) with arbitrary contrast. First, the induction current is reconstructed for radiation of each transmitter. Then, the amplitude of all reconstructed induction currents are summed with each other as a suitable function to estimate the location and shape of the scatterers. The performance of the introduced procedure is verified using some examples. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1248–1251, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23334
Internal multiband loop antenna for GSM/DCS/PCS/UMTS operation in the small‐size mobile device
Authors: Lin Chun‐I , Wong Kin‐Lu 
Published: March 2008

AbstractAn internal multiband loop antenna suitable for application in the small‐size mobile device (groundplane length 50 mm only) is presented. Along the loop strip of the antenna, it is configured to have two symmetric meandered sections and a central widened section. With the configured loop strip, three resonant loop modes (0.5‐, 1.0‐, and 1.5‐wavelength loop modes) can be excited to form two wide operating bands centered at about 900 and 1900 MHz for GSM/DCS/PCS/UMTS operation in the small‐size mobile device. In addition, the loop antenna along with the short ground plane studied here shows near‐omnidirectional radiation patterns in the azimuthal plane for frequencies over the antenna's two wide operating bands, which is different from conventional internal mobile phone antennas and is advantageous for practical applications. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1279–1285, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23337
Actively and passively excited sinusoidal microstrip and PCB strip antennas operating at K and millimeter‐wave bands
Authors: Salman A. O. , Cetinkaya H. , Vertiy A. A. 
Published: March 2008

AbstractActively and passively excited sinusoidal wire structure is applied to the PCB strip and microstrip structures successfully at K and millimeter‐wave frequency bands. Antenna dimensions are reduced till the half value, and more rigid structure is also obtained than the sinusoidal wire antennas by this way. Actively excited PCB sinusoidal antennas are investigated at these high frequencies and passively excited ones are introduced in the literature for the first time in this study. Transversely polarized broadside radiation is obtained for both types of antenna. The measured field patterns are compared with the calculated and simulated ones. The calculated patterns, phase velocity, and attenuation constants of investigated antennas are calculated by a written MATLAB code based the analytical approach. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1302–1308, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23347
Flexible multi‐T‐shaped monopole antenna for broadband operation
Authors: Jung Jinwoo , Lee Hyeonjin , Lim Yeongseog 
Published: March 2008

AbstractA novel broadband multi‐T‐shaped monopole antenna is presented. The proposed antenna has a broadband impedance bandwidth of 32.9%, which covers PCS, UMTS, WiBro, and WLAN bands. For frequencies over the operating bands, the proposed antenna displays omni‐directional radiation patterns. The proposed antenna has compact dimensions of 14 mm × 14 mm. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1251–1253, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23355
High‐frequency characterization of packaging network in TO‐CAN photodiode modules
Authors: Zhu N. H. , Wen J. M. , Zhang S. J. 
Published: March 2008

AbstractA simple method for analyzing the effects of TO packaging network on the high‐frequency response of photodiode modules is presented. This method is established based on the relations of the scattering parameters of the packaging network, photodiode chip, and module. It is shown that the results obtained by this method agree well with those obtained by the conventional comparison method. The proposed method is much more convenient since only the electrical domain measurements are required. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1219–1223, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23356
Compact dual‐band bandpass filter using stepped impedance resonators
Authors: Xu He‐Ming , Xiao Zhong‐Yin , Hu Hong‐Hong 
Published: March 2008

AbstractA new dual‐band bandpass filter (BPF) for 2.4/5.2 GHz WLAN systems using two‐stepped impedance resonators is presented. With new properly coupled structure, this filter appears very compact and easy to be fabricated. Measured results show that this BPF has low insertion loss of 0.3 dB at 2.4 GHz and 0.7 dB at 5.2 GHz, and wide fractional bandwidths of 30% for the first band and 17% for the second band, respectively. Measured results are in good agreement with the simulated ones. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1292–1294, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23357
MIMO capacity dependence on realistic cross‐polarization and branch power ratios
Authors: Landon David , Furse Cynthia 
Published: March 2008

AbstractThe dependence of channel capacity on cross‐polarization and the branch power ratio is established over a wide range of both realistic and idealized values. An existing empirical model is adjusted to avoid self‐contradictory results for cross‐coupled, but uncorrelated energy. Typical ranges are highlighted for realistic channel measurements from the literature, and extreme cases are identified. The value of a peak capacity measure is established and compared with the outage and average capacities. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1384–1388, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23360
Parasitic coupled T‐shaped microstrip patch antenna
Authors: Neog D. K. , Pattnaik S. S. 
Published: March 2008

AbstractA parasitic‐coupled T‐shaped microstrip patch antenna is discussed in this article. The T‐shaped microstrip patch antenna gives dual band resonant frequency on a thin substrate. The two resonant frequencies are within the 3 dB bandwidth that shows wide bandwidth. The experimental result is in good agreement with the calculated result. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1339–1341, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23363
A 60 GHz multiport front‐end architecture with integrated phased antenna array
Authors: Moldovan E. , Tatu S. O. , Affes S. 
Published: March 2008

AbstractA new front‐end architecture dedicated to 60 GHz high‐speed short‐range communications is proposed. Multiport circuits based on hybrid couplers are intensively used for both phased antenna array and down‐conversion. The front‐end, integrated in planar technology on ceramic substrate, use several IF quadrature conversion circuits, corresponding to multiple directions of arrival. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1371–1376, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23367
Low‐profile wideband MIMO antenna with suppressing mutual coupling between two antennas
Authors: Kim Ilkyu , won Jung Chang , Kim Yongjin , eil Kim Young 
Published: March 2008

AbstractA planar wideband multi‐input multi‐output (MIMO) antenna for small mobile devices is introduced. The proposed MIMO antenna system made up with two identical antennas operates in 2.3–5.9 GHz, which corresponds to Wibro 802.11a, 802.11b and Mobile WiMax 802.11n bands. The enhanced performance is obtained by placing antennas uniquely to suppress mutual coupling and utilizing supplemental structure to miniaturize the size of the antennas. The proposed antenna system is useful in wideband MIMO system, especially embedded in small mobile devices. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1336–1339, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23368