bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fragmentation studies of pentacoordinated bisaminoacylspirophosphoranes by negative electrospray ionization mass spectrometry
Authors: Cao Shuxia , Guo Yanchun , Wu Xinshuai , Zhao Huamin , Zhao Yufen 
Published: March 2011

AbstractFragmentation pathways of a series of pentacoordinated bisaminoacylspirophosphoranes were elucidated by electrospray ionization multistage mass spectrometry (ESI‐MSn) in negative mode. The deprotonated ions of pentacoordinated bisaminoacylspirophosphoranes tend to eliminate a corresponding amino acid to form base peak. The hydrogen/deuterium exchange experiment, the high‐resolution mass spectrometry, 13C stable isotope labeling experiment and theoretical calculations were used to rationalize the proposed fragmentation pathways and to verify the differences between the fragmentation pathways. The results indicate that the negative molecular ions of pentacoordinated bisaminoacylspirophosphoranes dissociate through its open‐chain tricoordinated tautomers. The relative Gibbs free energies (ΔG) of the product ions and proposed fragmentation pathways were estimated using the B3LYP/6‐31 + + G(d, p) model. The results have some potential applications in the identification structures of similar spirophosphorane compounds by ESI‐MSn. Copyright © 2011 John Wiley & Sons, Ltd.
Application of complementary mass spectrometric techniques to the identification of ketoprofen phototransformation products
Authors: Kosjek Tina , Perko Silva , Heath Ester , Kralj Bogdan , Žigon Dušan 
Published: March 2011

AbstractKetoprofen (KP) is a nonsteroidal anti‐inflammatory drug, which during UV irradiation rapidly transforms into benzophenone derivatives. Such transformation products may occur after topical application of KP, which is then exposed to sunlight resulting in a photo‐allergic reaction. These reactions are mediated by the benzophenone moiety independently of the amount of allergen. The same reactions will also occur during wastewater or drinking water treatment albeit their effect in the aqueous environment is yet to be ascertained. In addition, only a few such transformation products have been recognised. To enable the detection and structural elucidation of the widest range of KP transformation products, this study applies complementary chromatographic and mass spectrometric techniques including gas chromatography coupled to single quadrupole or ion trap mass spectrometry and liquid chromatography hyphenated with quadrupole–time‐of‐flight mass spectrometry. Based on structural information gained in tandem and multiple MS experiments, and on highly accurate molecular mass measurements, chemical structures of 22 transformation products are proposed and used to construct an overall breakdown pathway. Among the identified transformation products all but two compounds retained the benzophenone moiety—a result, which raises important issues concerning the possible toxic synergistic effects of KP and its transformation products. These findings trigger further research into water treatment technologies that would limit their entrance into environmental or drinking waters. Copyright © 2011 John Wiley & Sons, Ltd.
Spatial coherence of rainfall variations using the Oklahoma Mesonet
Authors: Boone K. Margret , McPherson Renee A. , Richman Michael B. , Karoly David J. 
Published: March 2011

AbstractStudies on precipitation patterns and the spatial distribution of precipitation are beneficial for many aspects of society, including agriculture, transportation, and business. In this research, data from over 100 Oklahoma Mesonet stations were used in a space‐time decomposition of Oklahoma rainfall from 1 March 1994 to 31 December 2003. Spatially coherent patterns of annual, warm‐season, and cold‐season rainfall events were derived using principal component analysis. Because the Oklahoma Mesonet records rainfall every 5 min, relatively short events (e.g. 15 min or 3 h) could be examined. Moreover, rainfall events were split into warm season and cold season to better understand the spatial differences by precipitation type (e.g. stratiform or convective). The results were not sensitive to domain size or shape.For 24‐h, 3‐h, and 15‐min rainfall accumulations, four similar coherent rainfall patterns were identified, located across NW, NE, SE, and SW Oklahoma. As expected, as the timescales considered became smaller, the spatial scale of the patterns, especially from the 24‐h to the 15‐min pattern, decreased slightly. The 15‐min rainfall analysis also identified a fifth region of coherent rainfall in central Oklahoma that was not identified in the first four principal components (PCs) of the 24‐h or 3‐h rainfall. The associated PC scores verified the rainfall patterns described by the PC loadings. Warm‐season and cold‐season rainfall patterns also were calculated for the 24‐h, 3‐h, and 15‐min rainfall accumulations. There was not much difference between the warm‐season and cold‐season rainfall patterns, both demonstrating coherent regions in the four quadrants of Oklahoma. Copyright © 2011 Royal Meteorological Society
Flame temperature diagnostics with water lines using mid‐infrared degenerate four‐wave mixing
Authors: Sun Z. W. , Li Z. S. , Li B. , Aldén M. 
Published: March 2011

AbstractThe feasibility of using degenerate four‐wave mixing (DFWM) for hot gas thermometry in the mid‐infrared spectral region is, for the first time, demonstrated by probing molecular ro‐vibrational transitions of water. DFWM spectra of hot water were recorded in specially designed flames, providing a series of temperatures varying from 1000 to 1900 K and, the dramatic spectral structure variations were used as temperature indicator. The intensity ratios between two hot water line groups at around 3231 cm−1 were especially studied and composed into a calibration table for flame temperature measurement using DFWM spectra. The saturation properties of different lines were also studied by recording the line intensity ratios as a function of laser power, and the results indicated that saturated excitation was in favor of reliable temperature measurements. As validation, infrared DFWM spectra in an φ = 1.52 flat premixed methane/air flame were recorded, and a good temperature value was obtained. Moreover, the recently released HITEMP2010 database as well as its previous version HITEMP2000 were adopted to simulate the hot water spectra and to analyze the line intensity ratios. Copyright © 2011 John Wiley & Sons, Ltd.
Arrhenius parameters for the gas‐phase reactions of O3 with two butenes and two methyl‐substituted butenes over the temperature range of 295–351 K
Authors: Shi Yuzhen , Xu Yongfu , Jia Long 
Published: March 2011

AbstractGas‐phase reactions of ozone with two butenes (1‐butene and isobutene) and two methyl‐substituted butenes (2‐methyl‐1‐butene and 3‐methyl‐1‐butene) have been studied in an indoor chamber at 295–351 K. The O3 concentrations were monitored by Model 49C‐Ozone analyzer. The butene concentrations were measured by gas chromatography–flame ionization detector. The Arrhenius expressions of k=3.50×10−15e(−1756±84)/T cm3 molecule−1 s−1, k=3.39×10−15e(−1697±52)/T cm3 molecule−1 s−1, k=6.18×10−15e−(1822±80)/T cm3 molecule−1 s−1, and k=7.24×10−14e−(2741±139)/T cm3 molecule−1 s−1 were obtained for the ozonolysis reactions of 1‐butene, isobutene, 2‐methyl‐1‐butene, and 3‐methyl‐1‐butene, respectively. Both the reaction rate constant and activation energy obtained in this work are in good agreement with those reported by using different techniques in the literature. © 2011 Wiley Peiodicals, Inc. Int J Chem Kinet 43: 238–246, 2011
Micro‐shear deformation of pure copper
Authors: Pfetzing‐Micklich J. , Brinckmann S. , Dey S.R. , Otto F. , Hartmaier A. , Eggeler G. 
Published: March 2011

AbstractIn this paper a new micro‐shear experiment is introduced using a double shear specimen machined by a focused ion beam technique. The micro‐shear specimen is structured from pure copper promoting (111) [101] slip. Comparing scanning electron microscopy images before and after deformation provides evidence for localized shear. Load‐displacement data identify a load plateau and characterize the localized shear process (critical shear‐stress for activation of (111) [101] slip: 170 MPa).
Tremor severity and age: A cross‐sectional, population‐based study of 2,524 young and midlife normal adults
Authors: Louis Elan D. , Hafeman Danella , Parvez Faruque , Liu Xinhua , Alcalay Roy N. , Islam Tariqul , Ahmed Alauddin , Siddique Abu Bakar , Patwary Tazul Islam , Melkonian Stephanie , Argos Maria , Levy Diane , Ahsan Habibul 
Published: March 2011

AbstractMild action tremor occurs in most normal people. Yet this tremor mainly has been studied within the context of advanced age rather than among the vast bulk of adults who are not elderly. Whether this tremor worsens during young and middle age is unknown. Using cross‐sectional data from a large population‐based study of young and midlife normal adults (age range, 18–60 years), we assessed whether increasing age is associated with more severe action tremor. Two thousand five hundred and twenty‐four adults in Araihazar, Bangladesh, drew an Archimedes spiral with each hand. Tremor in spirals was rated (0–3) by a blinded neurologist, and a spiral score (range, 0–6) was assigned. Spiral score was correlated with age (r = 0.06, P = .004). With each advancing decade, the spiral score increased (P = .002) so that the spiral score in participants in the highest age group (age 60) was approximately twice that of participants in the youngest age group (age 18–19); P = .003. In the regression model that adjusted for potential confounders (sex, cigarettes, medications, asthma inhalers, and tea and betel nut use), spiral score was associated with age (P = .0045). In this cross‐sectional, population‐based study of more than 2500 young and midlife normal adults, there was a clear association between age and tremor severity. Although the magnitude of the correlation coefficient was modest, tremor severity was higher with each passing decade. These data suggest that age‐dependent increase in tremor amplitude is not restricted to older people but occurs in all adult age groups. © 2011 Movement Disorder Society
A 77‐GHz PA with ground‐plane parasitic cancellation in a SiGe HBT BiCMOS technology
Authors: Giammello Vittorio , Ragonese Egidio , Palmisano Giuseppe 
Published: March 2011

AbstractThis letter presents a 77‐GHz power amplifier implemented in a SiGe BiCMOS technology featuring bipolar transistors with 160/175‐GHz fT/fmax. The circuit adopts a two stage differential topology with integrated input/output matching networks. The amplifier performance is considerably improved thanks to proper input/output LC resonant networks, which cancel out the ground‐plane parasitic effect. Matching networks use stacked transformers for impedance matching, differential‐to‐single‐ended conversion, and electro‐static discharge protection. The circuit achieves a power gain of 18.5 dB, a maximum output power of 11.6 dBm, with 4.2% power‐added efficiency, and an output 1‐dB compression point of 9.3 dBm. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:1413–1416, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25972
Ultra‐wideband bandpass filter with a notch band using EBG array etched ground
Authors: Chu H. , Shi X.Q. 
Published: March 2011

AbstractA novel ultra‐wideband (UWB) bandpass filter (BPF) with a notch band is proposed and implemented. The filter is realized by using a high‐pass filter (HPF) and an array of multiband electromagnetic bandgap (EBG) cells etched on the ground of a 50‐Ω microstrip line. The first and third stopband of the designed EBG array generate sharp falling edges at each side of the passband of the UWB BPF, whereas the second stopband creates a desired notch response. As it is the passband of the designed EBG array at lower frequency, a HPF is involved. The proposed filter was successfully designed, simulated, and fabricated. The measured results show that the proposed BPF has a wide bandwidth from 3.8 to 10.1 GHz with a notch response centered at 5.1 GHz. Both simulated and measured results are described. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:1290–1293, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25978
Dielectric characterization study of liquid‐based materials for mimicking breast tissues
Authors: Romeo Stefania , Di Donato Loreto , Bucci Ovidio Mario , Catapano Ilaria , Crocco Lorenzo , Scarfì Maria Rosaria , Massa Rita 
Published: March 2011

AbstractThe possibility of mimicking different types of breast tissues to realize experimental phantoms has been investigated by measuring the complex permittivity of polyethylene glycol mono phenyl ether (Triton X‐100) and distilled water solutions. In this respect, broad band electromagnetic characterization of several mixtures, at different concentrations, has been carried out in the 0.5–12 GHz frequency range. The good fitting between the dielectric properties of mammary tissues and that of the proposed mixtures, and the stability against temperature in the range 18–30 °C, suggest the possibility of mimicking the dielectric characteristics of breast tissues using easily available and low cost materials. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:1276–1280, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26001
Time‐domain augmented EFIE and its marching‐on‐in‐degree solution
Authors: Shi Yan , Jin Jian‐Ming 
Published: March 2011

AbstractA time‐domain augmented electric field integral equation (TDAEFIE) and its marching‐on‐in‐degree (MOD) solution are presented for analysis of transient electromagentic responses from three‐dimensional closed conducting bodies of arbitrary shape.By enforcing a condition on the normal component of the electric flux density, the TDAEFIE eliminates the potential internal resonance problem of the time‐domain electric field integral equation (TDEFIE) algorithm. With the use of weighted Laguerre polynomials as entire‐domain temporal basis functions, the MOD solution overcomes the late‐time instability problem that often occurs in the marching‐on‐in‐time (MOT) approach. Compared with the MOD solution of the time‐domain combined field integral equation (TDCFIE), the MOD solution of the TDAEFIE is more efficient because it takes less computational time for calculating the matrix elements and the matrix‐vector multiplications related to the excitation at the right‐hand side of the matrix equation. Numerical results are presented to illustrate the good performance of the TDAEFIE algorithm. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:1439–1444, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26015
Multicoil shimming of the mouse brain
Authors: Juchem Christoph , Brown Peter B. , Nixon Terence W. , McIntyre Scott , Rothman Douglas L. , de Graaf Robin A. 
Published: March 2011

AbstractMR imaging and spectroscopy allow the noninvasive measurement of brain function and physiology, but excellent magnetic field homogeneity is required for meaningful results. The homogenization of the magnetic field distribution in the mouse brain (i.e., shimming) is a difficult task due to complex susceptibility‐induced field distortions combined with the small size of the object. To date, the achievement of satisfactory whole brain shimming in the mouse remains a major challenge. The magnetic fields generated by a set of 48 circular coils (diameter 13 mm) that were arranged in a cylinder‐shaped pattern of 32 mm diameter and driven with individual dynamic current ranges of ±1 A are shown to be capable of substantially reducing the field distortions encountered in the mouse brain at 9.4 Tesla. Static multicoil shim fields allowed the reduction of the standard deviation of Larmor frequencies by 31% compared to second order spherical harmonics shimming and a 66% narrowing was achieved with the slice‐specific application of the multicoil shimming with a dynamic approach. For gradient echo imaging, multicoil shimming minimized shim‐related signal voids in the brain periphery and allowed overall signal gains of up to 51% compared to spherical harmonics shimming. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.
Flame retardancy mechanisms of phosphorus‐containing polyhedral oligomeric silsesquioxane (DOPO‐POSS) in polycarbonate/acrylonitrile‐butadiene‐styrene blends
Authors: Zhang Wenchao , Li Xiangmei , Yang Rongjie 
Published: March 2011

AbstractThe flame retardancy mechanisms of a novel polyhedral oligomeric silsesquioxane containing 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOPO‐POSS) in polycarbonate/acrylonitrile‐butadiene‐styrene (PC/ABS) blends are discussed. The thermal stability of PC/ABS composites with different DOPO‐POSS loadings are investigated by TGA and the enhancement of the thermal stability could be found at high temperature range. Their fire behavior is tested by the LOI, UL‐94, and cone calorimeter. Excellent flame retardancy of PC/ABS composites have been discovered with 10 wt% DOPO‐POSS loading. TGA‐FTIR, FTIR, XPS, and SEM, respectively, are used to characterize the gaseous products and the condensed residue in thermal decomposition, and the micro‐structure of the chars from cone calorimeter tests. The decomposition of PC/ABS with 10 wt% DOPO‐POSS shows significant changes compared with PC/ABS by TGA, FTIR, TGA‐FTIR, and XPS analysis. The enhancement of the thermal‐oxidative stability of PC/ABS with DOPO‐POSS is attributed to the interaction between DOPO‐POSS and PC/ABS at high temperature, which might be the key for improvement of the flame retardancy. Copyright © 2011 John Wiley & Sons, Ltd.
Preparation and performance of a novel polyimide foam
Authors: Liu Xiao‐Yan , Zhan Mao‐Sheng , Wang Kai , Li Yin , Bai Yi‐Feng 
Published: March 2011

AbstractA new type of polyimide foam (PIF) was prepared and characterized based on a one‐pot process by the reaction of a first solution with different ratios of a second solution. The first solution was comprised of pyromellitic dianhydride (PMDA), N, N‐dimethyl formamide (DMF), methanol, water, surfactant, and catalysts, while the second solution contained polyaryl polymethylene isocyanate (PAPI). In the present study, the relationships among compositions, structures, and properties of PIFs were investigated. The results indicated that with the increase in the weight ratio of PAPI/(first solution), the foaming degrees of PIFs increased from 10.14 to 10.52 times and the apparent densities before postcure decreased from 15.96 to 14.51 kg/m3. The open cell contents, average sound absorption coefficients, and average cellular diameters of PIFs after postcure increased with increase in the weight ratio of PAPI/(first solution). The glass transition temperatures (Tg) of PIFs after postcure first increased from 287 to 299°C, then decreased to 292°C, and the 5% weight loss temperatures and 10% weight loss temperatures presented the same trend as well. The compressive and flatwise tensile properties scaled very well with the relative densities of the foams after postcure, with the highest compressive strength of 0.03 MPa and the highest flatwise tensile strength of 0.15 MPa. Copyright © 2011 John Wiley & Sons, Ltd.
Zic2 synergistically enhances Hedgehog signalling through nuclear retention of Gli1 in cervical cancer cells
Authors: Chan David W , Liu Vincent WS , Leung Ling Yang , Yao Kwok Ming , Chan Karen KL , Cheung Annie NY , Ngan Hextan YS 
Published: March 2011

AbstractAberrant activation of Hedgehog (Hh) signalling has been implicated in the pathogenesis of human cancers. However, the cognate molecular mechanisms contributing to this disregulated pathway are incompletely understood. In this study, we showed that Zic2 was frequently over‐expressed and associated with high‐grade cervical cancer (p = 0.032), high levels of Gli1 (p < 0.001) and CyclinD1 (p < 0.001) by immunohistochemical and quantitative RT–PCR analyses. Further biochemical studies using luciferase reporter, co‐immunoprecipitation, subcellular fractionation and immunofluorescence analyses demonstrated that Zic2 can physically interact with Gli1 and retain it in the nucleus, which in turn increases Gli‐mediated transcriptional activity. Gain‐ and loss‐of‐function analyses of Zic2 showed that Zic2 could increase Hh signalling activity, cell proliferation and anchorage‐independent growth ability in cervical cancer cells. Conversely, deletion of the zinc finger domain at C‐terminus of Zic2 significantly abrogated its interaction with Gli1, the retention of Gli1 in the nucleus, effects on Hh signalling activity and oncogenic properties in cervical cancer cells. Our findings suggest that Zic2 is a positive modulator increasing Gli1 transcriptional and oncogenic activity by retaining Gli1 in the nucleus of cervical cancer cells. Copyright © 2011 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
The effects of nanoclay on the extrusion foaming of wood fiber/polyethylene nanocomposites
Authors: Lee Yoon H. , Kuboki Takashi , Park Chul B. , Sain Mohini 
Published: March 2011

AbstractThis article presents the foaming behaviors of wood fiber/high density polyethylene (HDPE) composites with small amounts of nanoclay. Melt compounding is used to prepare two types of clay‐filled wood fiber composites: intercalated and exfoliated clay composites. Their respective morphologies are determined using wide‐angle X‐ray diffraction (XRD) and transmission electron microscopy (TEM). We subsequently conduct an extrusion foaming experiment of the composites using N2 as the blowing agent. Varying the wood fiber content, as well as the processing parameters, such as temperature and pressure, the effects of different amounts of clay and the degree of exfoliation on the final cell morphology and the foam density of the wood fiber/HDPE/clay nanocomposite foams are studied. The results suggested that the addition of nanoclay improved the cell morphology of the wood fiber/HDPE composite foams as its content and degree of dispersion increased. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers
Formation and structure of organized molecular films for organo‐modified montmorillonite and mixed monolayer behavior with poly(L‐lactide)
Authors: Fujimori Atsuhiro , Kusaka Jun‐Ichi , Nomura Rintaro 
Published: March 2011

AbstractWe investigated the molecular orientation and surface morphology of organized molecular films with regard to solid‐state structures for organo‐modified montmorillonites by surface pressure‐area (π − A) isotherm, in‐plane and out‐of plane X‐ray diffraction (XRD), and atomic force microscopy (AFM). From the results of out‐of plane XRD, formation of highly ordered layer structure was confirmed in these clay Langmuir‐Blodgett (LB) film. Further, two‐dimensional lattice of long alkyl chain of organo‐modified parts packed hexagonally or orthorhombically in the films. Surface morphology of Z‐type monolayers on solid of organo‐modified montmorillonites indicates heterogeneous modification ratio in montmorillonite surface by AFM observation. In addition, monolayer behavior on the water surface and mesoscopic morphological formation on solid of mixed films of organo‐modified montmorillonite and poly‐(L‐lactide) (PLLA) were investigated by π − A isotherm and AFM. Collapsed surface pressures are independent on the mixed ratio, and indicate almost constant value in their isotherms. This tendency is a peculiarity of immiscible system. From the result of AFM observation, phase separated structure was confirmed in mesoscopic scales. This phase separated morphology remarkably varied with mixed ratio. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers