bluuebunny/crossref_metadata_2025_split huggingface dataset:
HILIC separation and quantitation of water‐soluble vitamins using diol column
Authors: Karatapanis Andreas E. , Fiamegos Yiannis C. , Stalikas Constantine D. 
Published: March 2009

AbstractHydrophilic interaction liquid‐chromatography (HILIC) in conjunction with diode array detection has been applied for the separation of selected‐water‐soluble vitamins using an end‐capped HILIC‐diol column. Vitamins with significant biological importance, such as thiamine (B1), riboflavin (B2), nicotinic acid (B3), nicotinamide (B3), pyridoxine (B6), folic acid (B9), cyanocobalamin (B12) and ascorbic acid (vitamin C) were simultaneously separated. Chromatographic conditions including type and percentage of organic modifier in the mobile phase, pH, type and concentration of buffer salt and flow rate were investigated. ACN was shown to offer superior separation for the compounds tested as compared to methanol, isopropanol and THF. Isocratic separation and analysis were achieved for six vitamins (B1, B2, nicotinic acid/nicotinamide, B6 and C) at ACN–H2O 90:10, containing ammonium acetate 10 mM, triethylamine 20 mM, pH 5.0, using a flow rate of 0.8 mL/min, while a gradient was necessary to resolve a mixture of all eight water‐soluble vitamins. The HILIC method was validated and successfully applied to the analysis of a pharmaceutical formulation and an energy drink negating the need for time consuming clean‐up steps.
HPLC enantioseparation of β2‐homoamino acids using crown ether‐based chiral stationary phase
Authors: Berkecz Róbert , Ilisz István , Misicka Aleksandra , Tymecka Dagmara , Fülöp Ferenc , Choi Hee Jung , Hyun Myung Ho , Péter Antal 
Published: March 2009

AbstractRP high‐performance liquid chromatographic methods were developed for the enantioseparation of eleven unusual β2‐homoamino acids. The underivatized analytes were separated on a chiral stationary phase containing (+)‐(18‐crown‐6)‐2,3,11,12‐tetracarboxylic acid as chiral selector. The effects of organic (alcoholic) and acidic modifiers, the mobile phase composition and temperature on the separation were investigated. The structures of the substituents in the α‐position of the analytes substantially influenced the retention and resolution. The elution sequence was determined in some cases: the S enantiomers eluted before the R enantiomers.
Peptide nucleic acid (PNA) binding and its effect on in vitro transcription in friedreich's ataxia triplet repeats
Authors: Belotserkovskii Boris P. , Liu Richard , Hanawalt Philip C. 
Published: March 2009

AbstractPeptide nucleic acids (PNAs) are DNA mimics in which peptide‐like linkages are substituted for the phosphodiester backbone. Homopyrimidine PNAs can invade double‐stranded DNA containing the homologous sequence by displacing the homopyrimidine strand from the DNA duplex and forming a PNA/DNA/PNA triplex with the complementary homopurine strand. Among biologically interesting targets for triplex‐forming PNA are (GAA/CTT)n repeats. Expansion of these repeats results in partial inhibition of transcription in the frataxin gene, causing Friedreich's ataxia. We have studied PNA binding and its effect on T7 RNA polymerase transcription in vitro for short repeats (n = 3) and for long repeats (n = 39), placed in both possible orientations relative to the T7 promoter such that either the GAA‐strand, or the CTT‐strand serves as the template for transcription. In all cases PNA bound specifically and efficiently to its target sequence. For the short insert, PNA binding to the template strand caused partial transcription blockage with well‐defined sites of RNA product truncation in the region of the PNA‐binding sequence, whereas binding to the nontemplate strand did not block transcription. However, PNA binding to long repeats, whether in the template or the nontemplate strand, resulted in a dramatic reduction of the amount of full‐length transcription product, although in the case of the nontemplate strand there were no predominant truncation sites. Biological implications of these results are discussed. © 2009 Wiley‐Liss, Inc.
Non‐B DNA conformations as determinants of mutagenesis and human disease
Authors: Bacolla Albino , Wells Robert D. 
Published: March 2009

AbstractRepetitive DNA motifs may fold into non‐B DNA structures, including cruciforms/hairpins, triplexes, slipped conformations, quadruplexes, and left‐handed Z‐DNA, thereby representing chromosomal targets for DNA repair, recombination, and aberrant DNA synthesis leading to repeat expansion or genomic rearrangements associated with neurodegenerative and genomic disorders. Hairpins and quadruplexes also determined the relative abundances of simple sequence repeats (SSR) in vertebrate genomes, whereas strong base stacking has permitted the expansion of purine·pyrimidine‐rich SSR during evolutionary time. SSR are enriched in regulatory and cancer‐related gene classes, where they have been actively recruited to participate in both gene and protein functions. SSR polymorphic alleles in the population are associated with cancer susceptibility, including within genes that appear to share regulatory circuits involving reactive oxygen species. © 2009 Wiley‐Liss, Inc.
Checkpoint responses to unusual structures formed by DNA repeats
Authors: Voineagu Irina , Freudenreich Catherine H. , Mirkin Sergei M. 
Published: March 2009

AbstractDNA sequences that are prone to adopting non‐B DNA secondary structures are associated with hotspots of genomic instability. The fine mechanisms by which alternative DNA structures induce phenomena such as repeat expansions, chromosomal fragility, or gross chromosomal rearrangements are under intensive studies. It is well established that DNA damage checkpoint responses play a crucial role in maintaining a stable genome. It is far less clear, however, whether and how the checkpoint machinery responds to alternative DNA structures. This review discusses the role of the interplay between DNA damage checkpoints and alternative DNA structures in genome maintenance. © 2009 Wiley‐Liss, Inc.
Genetic instabilities of (CCTG)·(CAGG) and (ATTCT)·(AGAAT) disease‐associated repeats reveal multiple pathways for repeat deletion
Authors: Edwards Sharon F. , Hashem Vera I. , Klysik Elzbieta A. , Sinden Richard R. 
Published: March 2009

AbstractThe DNA repeats (CTG)·(CAG), (CGG)·(CCG), (GAA)·(TTC), (ATTCT)·(AGAAT), and (CCTG)·(CAGG), undergo expansion in humans leading to neurodegenerative disease. A genetic assay for repeat instability has revealed that the activities of RecA and RecB during replication restart are involved in a high rate of deletion of (CTG)·(CAG) repeats in E. coli. This assay has been applied to (CCTG)·(CAGG) repeats associated with myotonic dystrophy type 2 (DM2) that expand to 11 000 copies and to spinocerebellar ataxia type 10 (SCA10) (ATTCT)·(AGAAT) repeats that expand to 4500 copies in affected individuals. DM2 (CCTG)·(CAGG) repeats show a moderate rate of instability, less than that observed for the myotonic dystrophy type 1 (CTG)·(CAG) repeats, while the SCA10 (ATTCT)·(AGAAT) repeats were remarkably stable in E. coli. In contrast to (CTG)·(CAG) repeats, deletions of the DM2 and SCA10 repeats were not dependent on RecA and RecB, suggesting that replication restart may not be a predominant mechanism by which these repeats undergo deletion. These results suggest that different molecular mechanisms, or pathways, are responsible for the instability of different disease‐associated DNA repeats in E. coli. These pathways involve simple replication slippage and various sister strand exchange events leading to deletions or expansions, often associated with plasmid dimerization. The differences in the mechanisms of repeat deletion may result from the differential propensity of these repeats to form various DNA secondary structures and their differential proclivity for primer–template misalignment during replication. © 2009 Wiley‐Liss, Inc.
Monozygotic female twins discordant for phenotype of Wilson's disease
Authors: Członkowska Anna , Gromadzka Grażyna , Chabik Grzegorz 
Published: March 2009

AbstractWilson's disease (WD) is an autosomal recessive disorder characterized by the functional disruption of the copper‐transporting protein adenosine triphosphatase 7B (ATP‐ase 7B). The disease is caused by mutations in ATP7B gene. It seems that the type of mutation in ATP7B only to some degree determines phenotypic manifestation of WD. We examined two pairs of monozygotic twins discordant for WD phenotype. The first set of twins were ATP7B compound heterozygotes c.3207C>A (p.H1069Q)/c.1211_1212insA (p.N404Kfs). The index case developed severe liver failure followed by depressive symptoms, dysarthria, and tremor at the age of 36. Her sister remained presymptomatic at diagnosis at the age of 39. The second twins were ATP7B c.3207C.A (p.H1069Q) homozygotes. The index case presented with dysarthria and tremor at the age of 26. Her sister remained clinically presymptomatic at diagnosis at the age of 28. We concluded that the phenotypic characteristics of WD are possibly attributable to epigenetic/environmental factors. © 2009 Movement Disorder Society
Determinants of quality of life in children with Gilles de la Tourette syndrome
Authors: Bernard Bryan A. , Stebbins Glenn T. , Siegel Sandra , Schultz Theresa M. , Hays Cynthia , Morrissey Mary J. , Leurgans Sue , Goetz Christopher G. 
Published: March 2009

AbstractThe objective of this study is to assess the association between tic severity, attention deficit disorder, obsessive‐compulsive behavior, and quality of life (QOL) in children with Gilles de la Tourette syndrome (GTS). GTS is a multidimensional disorder with disturbances in motor function and behavior. However, little is known about what variables are associated with QOL in these patients. We evaluated 56 outpatients with a diagnosis of GTS. The mean age was 10 (range 5–17 years). Tics were assessed with the Yale Global Tic Severity Scale (YGTSS). Behavioral scales included the Leyton Obsessional Inventory—Child Version, Children's Yale‐Brown Obsessive Compulsive Scale (CY‐BOCS), and Attention‐Deficit/Hyperactivity Disorder (ADHD) rating scale. The patient's parent also completed the TNO‐AZL Children's Quality of Life scale (TACQOL). YGTSS scores ranged from 4 to 30, indicating mild to moderate tic severity. Motor and phonic tic ratings were not correlated with QOL. However, both ADHD and OCD were significantly related to QOL. Subanalysis of ADHD subtypes demonstrated that inattentiveness but not hyperactivity predicted lower QOL. When ADHD, Leyton OCD, and tic severity were considered simultaneously, tic severity remained non‐significant, while both ADHD and OCD remained significant contributors to QOL. In summary, in patients with mild to moderate GTS, QOL relates primarily to co‐morbidities of ADHD and obsessive‐compulsive behavior. ADHD with predominantly inattentive symptoms, rather than hyperactivity symptoms, was associated with lower QOL. To improve QOL, clinicians must consider treatments of co‐morbidities among tic patients. © 2009 Movement Disorder Society
Stacked circular patch antenna with dual right/left hand circular polarization for wideband applications in X band
Authors: Masa‐Campos J. L. , Casla Sanz E. , Sierra‐Pérez M. , Fernandez J. M. 
Published: March 2009

AbstractA broadband circularly polarized patch antenna is presented in X band. The antenna operates simultaneously with left/right or right/left hand circular polarization in both reception (7.25–7.9 GHz) and transmission bands (7.9–8.4 GHz). A double coaxial probe feed has been implemented, as well as, a 90° branch‐line coupler to obtain the desired circular polarization. The undesired effects of the coaxial probe feed in such a broadband structure have been studied and compared with previously published works. Single element antenna and 2 × 2 array prototypes have been designed, manufactured, and measured. Good axial ratio, radiation pattern, and reflection results have been obtained. The improvement in the isolation between polarizations is exposed for the next step in the project schedule. The presented array will be part of a portable base station TX/RX antenna for satellite communications. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1419–1424, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24340
A CPW‐fed band‐notched slot antenna for UWB applications
Authors: Chiu Chien‐Wen , Li Chia‐Shan 
Published: March 2009

AbstractThis article presents a band‐notched planar slot antenna presented to overcome interference with some already existing standards such as the IEEE802.11a and HYPERLAN/2 systems. The slot antenna, evolved from an elliptical aperture antenna, is fed by CPW with an elliptical tuning‐stub to achieve UWB characteristics. This slot antenna, using open‐end slits on the tuning stub or a pair of parasitic strips in the aperture, is then designed to reject the sub‐band between 5 and 6 GHz. Practical structures are fabricated and the measured results show that this antenna not only retains an ultrawide bandwidth but also has band‐rejection capability. In addition, its radiation pattern preserved the omni‐directional feature, meeting the UWB system requirements. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1587–1592, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24343
A six‐phase divide‐by‐3 injection locked frequency divider in SiGe BiCMOS technology
Authors: Jang Sheng‐Lyang , Shen Kuan‐Chun , Chang Chia‐Wei , Juang Miin‐Horng 
Published: March 2009

AbstractThis article presents a six‐phase silicon‐germanium (SiGe) heterojunction bipolar transistor divide‐by‐3 injection locked frequency divider (ILFD). The ILFD is based on a three‐stage differential ring oscillator (voltage controlled oscillators) and was fabricated in the 0.35 μm SiGe 3P3M BiCMOS technology. The divide‐by‐3 function is performed by injecting a differential signal to the common gates of injection MOSFETs with the drain/sources connected to the VCO outputs. Measurement results show that when the supply voltage Vdd is tuned from 1.4 V to 2 V, the divider free‐running oscillation frequency is tunable from 6.2 GHz to 3.58 GHz, and at the incident power of 0 dBm the operation locking range is about 8.3 GHz, from the incident frequency 18.8 to 10.5 GHz. The core power consumption is 8.96 mW at Vdd = 1.4 V. The die area is 0.802 × 0.812 mm2. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1555–1557, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24345
Design, fabrication, simulation, and measurement of a dual‐band, planar, compact artificial magnetic conductor
Authors: Li Yading , Johnston Benjamin F. , Withford Michael J. , Esselle Karu P. 
Published: March 2009

AbstractBy introducing two orthogonal gaps to a uniplanar compact photonic bandgap structure, artificial magnetic conductor's resonance frequencies have been significantly reduced. Since this compact pattern needs slots with 0.05‐mm width, the laser micromachining was explored to fabricate the prototypes. Reflection coefficients were measured through a WR‐137 waveguide. Considering the dominant waves propagating in a waveguide, a simulation method is introduced. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1524–1527, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24346
Wideband vertical transitions for multilayer BCB‐based MCM
Authors: Ding Xiaoyun , Geng Fei , Luo Le 
Published: March 2009

AbstractFour wideband vertical transitions between transmission lines for multilayer benzocyclobutene‐based multichip module are presented for the first time. Their back‐to‐back configurations are designed and fabricated. The RF transition characteristics are simulated, measured, and analyzed. The measurement results reveal minor differences between these transitions, and low return loss and insertion loss can be obtained up to 40 GHz. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1584–1587, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24354
Small‐size printed loop antenna for penta‐band thin‐profile mobile phone application
Authors: Wong Kin‐Lu , Chen Wei‐Yu 
Published: March 2009

AbstractA planar printed loop antenna with a small area of 15 × 50 mm2 and capable of covering all five operating bands of GSM850/900/1800/1900/UMTS for WWAN (wireless wide area network) operation in the thin‐profile mobile phone is presented. The antenna is very suitable to be directly printed on the system circuit board of the mobile phone, making it easy to fabricate at low cost and generally showing no thickness above the circuit board; the latter is very attractive for thin‐profile mobile phone applications. In addition, the proposed loop antenna is very suitable to be printed at the bottom position of the mobile phone; in this case the antenna meets the SAR (specific absorption rate) limit for practical applications. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1512–1517, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24359
A position‐invariant calibration‐independent method for permittivity measurements
Authors: Hasar U. C. , Inan O. E. 
Published: March 2009

AbstractA simple yet powerful calibration‐independent method is proposed for complex permittivity extraction of dielectric materials. There are two main features of the method as follows: (a) it decreases any uncertainty arising from using a second (extra) sample and (b) it does not require precise location of the sample within its cell (a waveguide or coaxial‐line section). The disadvantage of the method is that it may produce some singularity points while extracting the complex permittivity from measurements. We validated the method by calibrated and uncalibrated complex scattering parameter measurements of a polyvinyl‐chloride (PVC) sample at X‐band (8.2–12.4 GHz). © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1406–1408, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24364
Low‐profile X antenna with flat reflector for polarization diversity applications
Authors: Hristov H. D. , Carrasco H. , Feick R. , Ooi B. L. 
Published: March 2009

AbstractFolded‐wire X antenna with two feed ports is introduced, which can operate like a half‐wave dipole, or array of two crossed dipoles depending on whether one or two ports are fed. The low‐profile location of 1.8‐GHz X antenna in front of flat plate makes a compact reflector antenna with a good input match in about 5% frequency band, gain of 8.5–9.0 dBi, and big inter‐port and cross‐polar isolations. The applications may include earth and satellite communication systems with polarization diversity action. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1508–1512, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24371
Design of a protective garment GPS antenna
Authors: Vallozzi L. , Vandendriessche W. , Rogier H. , Hertleer C. , Scarpello M. 
Published: March 2009

AbstractA protective garment patch GPS antenna, for wearable textile systems applications, was designed and, for the first time in literature, realized in fire‐resistant and water‐repellent textile materials, making it particularly suitable for integration into rescue workers' garments. Measurements show that the antenna still performs adequately even when covered with protective textiles, and when integrated into a jacket, worn on the human body. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1504–1508, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24372
Circularly polarized dielectric resonator‐loaded circular microstrip patch antennas for WLAN 2.4 GHz applications
Authors: Tsai Ching‐Long , Deng Sheng‐Ming , Chen Tsung‐Wen , Liu Li‐Wei 
Published: March 2009

AbstractDielectric resonator‐loaded circular microstrip patch antennas can be used as an alternative way to generate circular polarization. The dielectric resonator is placed on the edge of the circular microstrip patch antenna to result both strong coupling effect and two degenerated orthogonal modes. Then, we choose the feeding point, the placed position and size of DR, and the height of antenna as key tuning parameters; both wide circular polarization and impedance matching are achieved. Application is given for WLAN 2.4 GHz band. Both simulated and measured data are matched well. Measured results show that the center frequency is at 2.45 GHz. The impedance bandwidth is 19.2%. Besides, the axial ratio bandwidth is 3.7% (2.39–2.48 GHz). The radiation patterns are broadside radiations and high antenna gain of 8.6 dBic is achieved. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1470–1473, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24373
Air‐bridge‐integrated stub filter for submillimeter wave applications
Authors: Gu Dazhen , Rodriguez‐Morales Fernando , Yngvesson Sigfrid K. 
Published: March 2009

AbstractWe report a coplanar waveguide notch filter with an integrated air‐bridge, designed for operation at submillimeter wave frequencies and cryogenic temperatures. The filter is built with a planar slot‐ring antenna, which is in turn loaded with a superconducting mixer detector. The filter is designed to have a narrow‐band response with 40 dB of attenuation at 1.56 THz. The fabrication of the micrometer‐scale structure was accomplished by means of UV photolithography and electroplating. The optimized microelectronic fabrication process produced high yields and good reliability. Preliminary measurements of a submillimeter wave receiver based on this design showed satisfactory performance of the filter. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1436–1439, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24375
Concurrent dual‐band GaN power amplifier with compact microstrip matching network
Authors: Bespalko D. T. , Boumaiza S. 
Published: March 2009

AbstractA concurrent dual‐band power amplifier (PA) using circuit transformations in the design of the dual‐band matching networks (MN) are outlined and a transmission line compression technique is used reduce the insertion loss of the MNs. A 10‐W Gallium Nitride based PA operating concurrently at 2.5 GHz and 3.5 GHz is compared with the performance of the equivalent single‐band PAs. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1604–1607, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24380
A 2.4 GHz highly linear image‐rejection low noise amplifier by using an active inductor
Authors: Li Jain‐Yi , Chang Chin‐Sheng , Lin Wen‐Jeng , Chen Han‐Jan , Chen Lih‐Shan , Houng Mau‐Phon 
Published: March 2009

AbstractThis article presented a highly linear image‐rejection (IR) low‐noise amplifier (LNA) for 2.4 GHz band applications based on 0.18 μm CMOS technology. By using folded PMOS for sinking the third‐order intermodulation distortion (IMD3), the IR LNA has high input third‐order intercept point (IIP3) at 2.4 GHz. The IR filter, using a high quality factor (Q) active inductor, has 30 dB rejection for 1.6 GHz image band with intermediate frequency of 400 MHz. An IIP3 of +10 dBm was obtained with a gain of 16.8 dB, noise figure (NF) of 2.5 dB, and power consumption of 12 mW. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1570–1573, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24381