排序方式: 共有40条查询结果,搜索用时 125 毫秒
21.
Uemura YJ Luke GM Sternlieb BJ Brewer JH Carolan JF Hardy WN Kadono R Kempton JR Kiefl RF Kreitzman SR Mulhern P Riseman TM Williams DL Yang BX Uchida S Takagi H Gopalakrishnan J Sleight AW Subramanian MA Chien CL Cieplak MZ Xiao G Lee VY Statt BW Stronach CE Kossler WJ Yu XH 《Physical review letters》1989,62(19):2317-2320
22.
Marie-Claude Djidja Emmanuelle Claude Marten F. Snel Simona Francese Peter Scriven Vikki Carolan Malcolm R. Clench 《Analytical and bioanalytical chemistry》2010,397(2):587-601
The development of tissue micro-array (TMA) technologies provides insights into high-throughput analysis of proteomics patterns
from a large number of archived tumour samples. In the work reported here, matrix-assisted laser desorption/ionisation–ion
mobility separation–mass spectrometry (MALDI–IMS–MS) profiling and imaging methodology has been used to visualise the distribution
of several peptides and identify them directly from TMA sections after on-tissue tryptic digestion. A novel approach that
combines MALDI–IMS–MSI and principal component analysis–discriminant analysis (PCA–DA) is described, which has the aim of
generating tumour classification models based on protein profile patterns. The molecular classification models obtained by
PCA–DA have been validated by applying the same statistical analysis to other tissue cores and patient samples. The ability
to correlate proteomic information obtained from samples with known and/or unknown clinical outcome by statistical analysis
is of great importance, since it may lead to a better understanding of tumour progression and aggressiveness and hence improve
diagnosis, prognosis as well as therapeutic treatments. The selectivity, robustness and current limitations of the methodology
are discussed. 相似文献
23.
Anderson DM Carolan VA Crosland S Sharples KR Clench MR 《Rapid communications in mass spectrometry : RCM》2010,24(22):3309-3319
Pesticides are widely used in agriculture to control weeds, pests and diseases. Successful control is dependent on the compound reaching the target site within the organism after spray or soil application. Conventional methods for determining uptake and movement of herbicides and pesticides include autoradiography, liquid scintillation and chromatographic techniques such as high-performance liquid chromatography (HPLC). Autoradiography using radiolabelled compounds provides the best indication of a compound's movement within the plant system. Autoradiography is an established technique but it relies on the synthesis of radiolabelled compounds. The distribution of four sulfonylurea herbicides in sunflower plants has been studied 24 h after foliar application. The use of matrix-assisted laser desorption/ionisation mass spectrometry imaging (MALDI-MSI) images of protonated molecules and fragment ions (resulting from fragmentation at the urea bond within the sulfonylurea herbicides) has provided evidence for translocation above and below the application point. The translocation of nicosulfuron and azoxystrobin within the same plant system has also been demonstrated following their application to the plant stem. This study provides evidence that MALDI-MSI has great potential as an analytical technique to detect and assess the foliar, root and stem uptake of agrochemicals, and to reveal their distribution through the plant once absorbed and translocated. 相似文献
24.
R.H. Dee A.J. Berlinsky J.F. Carolan E. Klein N.J. Stone B.G. Turrell G.B. Street 《Solid State Communications》1977,22(5):303-306
Measurements of the complex A.C. susceptibility and magnetization of crystals of polysulphur nitride, (SN)x, are reported. At temperatures near 0.2K both the in-phase and quadrature components of the A.C. susceptibility show a marked change which can be related to the onset of superconductivity. However, changes in the sample magnetization could not be detected. 相似文献
25.
Chris Carolan Richard Dykstra 《Annals of the Institute of Statistical Mathematics》2003,55(3):487-497
The characterization of the least concave majorant of brownian motion by Pitman (1983,Seminar on Stochastic Processes, 1982 (eds. E. Cinlar, K. L. Chung and R. K. Getoor), 219–228, Birkhäuser, Boston) is tweaked, conditional on a vertex point. The joint distribution of this vertex point is derived and is shown to be generated with extreme ease. A procedure is then outlined by which one can construct the least concave majorant of a standard Brownian motion path over any finite, closed subinterval of (0, ∞). This construction is exact in distribution. One can also construct a linearly interpolated version of the Brownian motion path (i.e. we construct the Brownian motion path over a grid of points and linearly interpolate) corresponding to this least concave majorant over the same finite interval. A discussion of how to translate the aforementioned construction to the least concave majorant of a Brownian bridge is also presented. 相似文献
26.
H. Meyer P. G. Carolan N. J. Conway A. R. Field S. J. Fielding P. Helander 《Czechoslovak Journal of Physics》2000,50(12):1451-1461
On COMPASS-D the profile evolution of electron density, electron temperature, perpendicular electric field, poloidal impurity
velocity, and neutral density at the outboard mid-plane has been investigated during ohmic single null diverted (SND) discharges
undergoing an L/H, H/L, and another L/H transition. This was achieved using a novel combined diagnostic consisting of thermal
helium beam and Doppler spectrometry, sharing the same lines of sight. To generate the transitions first an ELM-free H-mode
phase was produced by terminating the gas fuelling. Within this H-mode a stepped gas puff was applied triggering an intermediate
L-mode phase followed by a second ELM-free phase. It was found that on COMPASS-D the L/H transition is not preceded by a change
in velocity or electric field shear. The maximum electric field shear of ∇ ▽E
ψ
≈2×103kV/m2 develops after the L/H transition around the 95% flux surface. Although the neutral density at the separatrix is of the ordern
D ≈ 1017m−3 no indication of a local influence could be concluded. However, a correlation between the decay of the shear and the gas
puff was observed.
Presented at the Workshop on Role of Electric Fields in Plasma Confinement and Exhaust, Budapest, 18–19 June 2000.
This work was jointly funded by the UK Department of Trade and Industry and EURATOM. The author H. Meyer is funded by a Marie
Curie Research Training Grant. 相似文献
27.
28.
Brendan Prideaux Sally J. Atkinson Vikki A. Carolan Jacqueline Morton Malcolm R. Clench 《International journal of mass spectrometry》2007,260(2-3):243
Aspects of the indirect examination of xenobiotic distribution on the surface of and within skin sections by imaging matrix assisted laser desorption ionisation mass spectrometry (MALDI-MS) have been examined. A solvent assisted blotting technique previously developed for the examination of the absorption of agrochemicals into leaves has been examined for the analysis of the distribution of hydrocortisone on the surface of skin. It was found that by careful control of the extraction and blotting procedure an 80-fold sensitivity improvement could by obtained over dry blotting with only 10% lateral diffusion of the image. However, in contrast it was found that the use of a hydrophobic blotting membrane was more suitable for the examination of the transdermal absorption of the pesticide chlorpyrifos.The potential of incorporating a derivatisation step into the solvent assisted blotting procedure was investigated by blotting isocyanate treated skin onto a methanol soaked blotting membrane. This served the dual purpose of derivatising the isocyanate to a stable substituted urea derivative and extracting it from the skin. Preliminary data indicate that this approach may have some merit for field sampling for such compound and clearly derivatisation also offers the potential for sensitivity enhancements.Finally, the use of principal components analysis with an ion species specific normalisation procedure is proposed to identify regions of drug treated skin where the ion abundance of the compound of interest is low. 相似文献
29.
The emerging area of DNA-based architectures and machines promises exciting opportunities and will impact on the future of DNA structures in nanobiotechnology. 相似文献
30.
James W. Pavlik Heather S T. Martin Karen A. Lambert Jennifer A. Lowell Vikki M. Tsefrikas Cheryl K. Eddins Naod Kebede 《Journal of heterocyclic chemistry》2005,42(2):273-281
5‐Phenylisoxazole ( 4 ) and 4‐phenylisoxazole ( 22 ) underwent phototransposition to 5‐phenyloxazole ( 5 ) and 4‐phenyloxazole ( 24 ) respectively. Labeling with deuterium or methyl confirmed that these phototranspositions occurred via the P4 pathway which involves only interchange of the N2 and C3 ring position. Thus, 4‐deuterio‐5‐phenylisoxazole ( 4‐4d ), 4‐methyl‐5‐phenylisoxazole ( 10 ), and 5‐methyl‐4‐phenylisoxazole ( 23 ) phototransposed to 4‐deuterio‐5‐phenyloxazole ( 5‐4d ), 4‐methyl‐5‐phenyloxazole ( 11 ), and 5‐methyl‐4‐phenyloxazole ( 25 ) respectively. In addition to phototransposition, isoxazoles 4, 10 , and 23 also underwent photo‐ring cleavage to yield benzoylacetonitrile (9), α‐benzoylpropionitrile ( 15 ), and aceto‐α‐phenylacetonitrile ( 26 ) respectively. Irradiation of 5‐phenyl‐3‐(trifluoromethyl)isoxazole ( 16 ) in acetonitrile led to 5‐phenyl‐2‐(trifluoromethyl)oxazole ( 17 ), the P4 phototransposition product. Irradiation of 16 in methanol led to a substantial decrease in the yield of 17 and to the formation of a mixture of (E) and (Z)‐2‐methoxy‐2‐(trifluoromethyl)‐3‐benzoylaziridines 18a and 18b . 相似文献