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141.
Shen Y Kennedy DF Greaves TL Weerawardena A Mulder RJ Kirby N Song G Drummond CJ 《Physical chemistry chemical physics : PCCP》2012,14(22):7981-7992
A series of 11 new protic ionic liquids with fluorous anions (FPILs) have been identified and their self-assembled nanostructure, thermal phase transitions and physicochemical properties were investigated. To the best of our knowledge this is the first time that fluorocarbon domains have been reported in PILs. The FPILs were prepared from a range of hydrocarbon alkyl and heterocyclic amine cations in combination with the perfluorinated anions heptafluorobutyrate and pentadecafluorooctanoate. The nanostructure of the FPILs was established by using small- and wide-angle X-ray scattering (SAXS and WAXS). In the liquid state many of the FPILs showed an intermediate range order, or self-assembled nanostructure, resulting from segregation of the polar and nonpolar hydrocarbon and fluorocarbon domains of the ionic liquid. In addition, the physicochemical properties of the FPILs were determined including the melting point (T(m)), glass transition (T(g)), devitrification temperature (T(c)), thermal stability and the density ρ, viscosity η, air/liquid surface tension γ(LV), refractive index n(D), and ionic conductivity κ. The FPILs were mostly solids at room temperature, however two examples 2-pyrrolidinonium heptafluorobutyrate (PyrroBF) and pyrrolidinium heptafluorobutyrate (PyrrBF) were liquids at room temperature and all of the FPILs melted below 80 °C. Four of the FPILs exhibited a glass transition. The two liquids at room temperature, PyrroBF and PyrrBF, had a similar density, surface tension and refractive index but their viscosity and ionic conductivity were very different due to dissimilar self-assembled nanostructure. 相似文献
142.
Low W Kang J DiGruccio M Kirby D Perrin M Fischer WH 《Journal of the American Society for Mass Spectrometry》2004,15(8):1156-1160
The ability of MALDI-MS to analyze photolabile arylazido peptide derivatives was investigated. Peptides containing UV-labile
p-azidobenzoyl groups were subjected to MALDI-MS analysis in a variety of matrices. As standard MALDI-MS employs a UV laser
(337 nm), we investigated conditions that would allow detection of the intact molecule ions for these light-sensitive peptides.
When using α-cyano-4-hydroxycinnamic acid (ACHC) or 2,5 dihydroxybenzoic acid (DHB) as the matrix, photoinduced degradation
products were prevalent. In contrast, when employing the matrix sinapinic acid, the intact molecule ion corresponding with
the azido peptide was the predominant signal. The protection of photolabile azido derivatives correlates with the UV absorbance
properties of the matrix employed, i.e., sinapinic acid, which exhibits a strong absorbance near 337 nm, most efficiently
protects the azido derivative from photodegradation. 相似文献
143.
In 2-aminopyridine the electronic origin band of the 2980 å electronic system, the longest wavelength system which has been observed, is shown to be a type B-type A hybrid band containing 55 ± 10 per cent of type A character. It follows that the electronic transition is 1 A′-1 A′ which implies a π*-π and not a π*-n electron promotion. The degree of type A character is interpreted as indicating a swing of the transition moment by 10 ± 10° from the b axis of pyridine (the in-plane axis perpendicular to C 2). Since it is expected that the first π*-π transition in pyridine has its transition moment polarized along the b axis the amino-group does not seem to perturb the pyridine transition strongly in this respect. The changes of rotational constants from the ground to the excited state in 2-aminopyridine are very similar to those in aniline and probably reflect similar changes in geometry, namely a substantial contraction of the C-NH2 bond, an opening of the internal ring angle adjacent to the substituent and a benzene-like expansion of the ring. The origin of the 0-0 band is at 33471·1 ± 0·1 cm-1. 相似文献
144.
Kirby C. Smith 《代数通讯》2013,41(6):2065-2077
Let R be a right near-ring with identity. The k×k matrix near-ring over R, Matk(R R), as defined by Meldrum and van der Walt, regards R as a left mod-ule over R. Let M be any faithful left R-module. Using the action of R on M, a generalized k×k matrix near-ring, Matk(R M), is defined. It is seen that Matk(R M) has many of the features of Matk(R R). Differences be-tween the two classes of near-rings are shown. In spe- cial cases there are relationships between Matk(R M) and Matk(R R). Generalized matrix near-rings Matk(R M) arise as the “right near-ring” of finite centraiizer near-rings of the form M A{G)> where G is a finite group and A is a fixed point free automorphism group on G. 相似文献
145.
H.F. Kirby T.M. EggersP.B. Jayathilaka S.M. CampbellCasey W. Miller 《Journal of magnetism and magnetic materials》2012
The exchange bias of the soft ferromagnet mu-metal, Ni77Fe14Cu5Mo4, with the metallic antiferromagnet Fe50Mn50 has been studied as a function of ferromagnet thickness and buffer layer material. Mu-metal exhibits classic exchange bias behavior: the exchange bias (HEB) and coercive fields scale inversely with the ferromagnet's thickness, with HEB varying as the cosine of the in-plane applied field angle. Ta buffers, rather than Cu, allow the mu-metal to retain more of its soft magnetic character while exhibiting exchange bias. The ability to preserve soft ferromagnetic behavior in an exchange biased heterostructure may be useful for low field sensing and other device applications. 相似文献
146.
Connelly JT Kondapalli S Skoupi M Parker JS Kirby BJ Baeumner AJ 《Analytical and bioanalytical chemistry》2012,402(1):315-323
An integrated microfluidic biosensor is presented that combines sample pre-concentration and liposome-based signal amplification
for the detection of enteric viruses present in environmental water samples. This microfluidic approach overcomes the challenges
of long assay times of cell culture-based methods and the need to extensively process water samples to eliminate inhibitors
for PCR-based methods. Here, viruses are detected using an immunoassay sandwich approach with the reporting antibodies tagged
to liposomes. Described is the development of the integrated device for the detection of environmentally relevant viruses
using feline calicivirus (FCV) as a model organism for human norovirus. In situ fabricated nanoporous membranes in glass microchannels
were used in conjunction with electric fields to achieve pre-concentration of virus–liposome complexes and therefore enhance
the antibody–virus binding efficiency. The concentrated complexes were eluted to a detection region downstream where captured
liposomes were lysed to release fluorescent dye molecules that were then quantified using image processing. This system was
compared to an optimized electrochemical liposome-based microfluidic biosensor without pre-concentration. The limit of detection
of FCV of the integrated device was at 1.6 × 105 PFU/mL, an order of magnitude lower than that obtained using the microfluidic biosensor without pre-concentration. This significant
improvement is a key step toward the goal of using this integrated device as an early screening system for viruses in environmental
water samples. 相似文献
147.
Mia A. Levy John B. Freymann Justin S. Kirby Andriy Fedorov Fiona M. Fennessy Steven A. Eschrich Anders E. Berglund David A. Fenstermacher Yongqiang Tan Xiaotao Guo Thomas L. Casavant Bartley J. Brown Terry A. Braun Andre Dekker Erik Roelofs James M. Mountz Fernando Boada Charles Laymon Matt Oborski Daniel L. Rubin 《Magnetic resonance imaging》2012
Introduction
The National Cancer Institute Quantitative Research Network (QIN) is a collaborative research network whose goal is to share data, algorithms and research tools to accelerate quantitative imaging research. A challenge is the variability in tools and analysis platforms used in quantitative imaging. Our goal was to understand the extent of this variation and to develop an approach to enable sharing data and to promote reuse of quantitative imaging data in the community.Methods
We performed a survey of the current tools in use by the QIN member sites for representation and storage of their QIN research data including images, image meta-data and clinical data. We identified existing systems and standards for data sharing and their gaps for the QIN use case. We then proposed a system architecture to enable data sharing and collaborative experimentation within the QIN.Results
There are a variety of tools currently used by each QIN institution. We developed a general information system architecture to support the QIN goals. We also describe the remaining architecture gaps we are developing to enable members to share research images and image meta-data across the network.Conclusions
As a research network, the QIN will stimulate quantitative imaging research by pooling data, algorithms and research tools. However, there are gaps in current functional requirements that will need to be met by future informatics development. Special attention must be given to the technical requirements needed to translate these methods into the clinical research workflow to enable validation and qualification of these novel imaging biomarkers. 相似文献148.
M.D. Rodríguez B. Afra C. Trautmann M. Toulemonde T. Bierschenk J. Leslie R. Giulian N. Kirby P. Kluth 《Journal of Non》2012,358(3):571-576
Swift heavy ion irradiated metallic glasses were studied using synchrotron based small angle X-ray scattering (SAXS). Ribbons of Fe80B20, Fe85 B15, Fe81B13.5Si3.5C2 and Fe40Ni40B20 were irradiated with 11.1 MeV/nucleon (MeV/u) 132Xe, 152Sm, 197Au and 8.2 MeV/u 238U ions to fluences between 1 × 1010 and 1 × 1012 ions/cm2. The SAXS measurements provide evidence for the formation of ion tracks and allow a quantitative analysis of the track ensemble in all studied materials. The ion tracks have been well described by cylinders with abrupt boundaries and an electronic density change of (0.03 ± 0.01)% between track and matrix material. An inelastic thermal spike model was fitted to the experimental track radii to determine the critical energy density required to create an ion track. Despite the similar energy loss and track cross-sections, 30% higher track creation threshold is apparent for the binary alloys. 相似文献
149.
Stephanie S. Peterson Tishal Kirby Mariappan Kadarkaraisamy Richard M. Hartshorn Andrew G. Sykes 《Polyhedron》2009,28(14):3031-3035
Reaction of Ag(I) and Cu(I) [M(NCCH3)4]X (X = BF4− and PF6−) salts with 1,8-bis(nicotinyloxy)anthracene-9,10-dione (1), 1,8-bis(isonicotinyloxy)anthracene-9,10-dione (2), and 1,8-bis(pyrimidine-5-carboxyloxy)anthracene-9,10-dione (3), yield new chelating and bridging complexes and two new coordination polymers. The bridging capabilities of ligands 1 and 2 have not been demonstrated before, and ligand 1, by itself, has the flexibility to produce either chelated or bridged structures and an unusual ladder coordination polymer. The tetradentate ligand 3 also produces a one-dimensional coordination polymer in the presence of one equivalent of Ag(I). All complexes have been characterized by X-ray crystallography. 相似文献
150.
E. A. Kravtsov D. Haskel S. G. E. te Velthuis J. S. Jiang B. J. Kirby 《Bulletin of the Russian Academy of Sciences: Physics》2010,74(10):1471-1473
The evolution of the magnetic structure of multilayer [Fe (35 Å)/Gd (50 Å)5] with variation in temperature and an applied magnetic field was determined using a complementary approach combining polarized neutron and X-ray resonant magnetic reflectometry. Self-consistent simultaneous analysis of X-ray and neutron spectra allowed us to determine the elemental and depth profiles in the multilayer structure with unprecedented accuracy, including the identification of an inhomogeneous intralayer magnetic structure with near-atomic resolution. 相似文献