1,334 research outputs found
FT-infrared spectroscopic studies of lymphoma, lymphoid and myeloid leukaemia cell lines
Get PDFThis paper presents a novel method to characterise spectral differences that
distinguish leukaemia and lymphoma cell lines. This is based on objective
spectral measurements of major cellular biochemical constituents and
multivariate spectral processing. Fourier transform infrared (FT-IR) maps of the
lymphoma, lymphoid and myeloid leukaemia cell samples were obtained using a
Perkin-Elmer Spotlight 300 FT-IR imaging spectrometer. Multivariate statistical
techniques incorporating principal component analysis (PCA) and linear
discriminant analysis (LDA) were used to construct a mathematical model. This
model was validated for reproducibility. Multivariate statistical analysis of
FTIR spectra collected for each cell sample permit a combination of unsupervised
and supervised methods of distinguishing cell line types. This resulted in the
clustering of cell line populations, indicating distinct bio-molecular
differences. Major spectral differences were observed in the 4000 to 800 cm-
1 spectral region. Bands in the averaged spectra for the cell line were assigned
to the major biochemical constituents including; proteins, fatty acids,
carbohydrates and nucleic acids. The combination of FT-IR spectroscopy and
multivariate statistical analysis provides an important insight into the
fundamental spectral differences between the cell lines, which differ according
to the cellular biochemical composition. These spectral differences can serve as
potential biomarkers for the differentiation of leukaemia and lymphoma cells.
Consequently these differences could be used as the basis for developing a
spectral method for the detection and identification of haematological
malignancies
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Measurement of high-p/sub T/ correlations in 340-GeV/c pp and 280-GeV/c. pi. /sup -/p reactions
No full textWe have measured correlations between single high-p/sub T/ (1.5 < p/sub T/ < 3.5 GeV/c) trigger particles on one side of the beam line and groups of particles entering a calorimeter on the opposite side of the beam line. The mean transverse momentum measured in the calorimeter is found to increase with the trigger-particle transverse momentum. The coplanarity of the events increases with trigger-particle transferse momentum. We have compared our data to the predictions of a phenomenological four-jet model. To fit our data we find that we must give large (0.9 GeV/c) mean transverse momenta to the constituents of the initial hadrons
IR-spectroscopy and IR-microscopy of human breast tumors, xenografted breast tumors, and breast tumor cell lines
No full textIR spectra of breast tumor cell lines and breast tumor tissues have been measured. IR measurements of tumor cells revealed that approximately 15 cells are necessary to obtain spectra of good signal-to-noise ratio using an IR microspectrometer equipped with a conventional IR thermal source. Comparative studies of human breast tumor cell line suspensions demonstrated that MCF-7 cells and drug-resistant NCI/ADR cells can be differentiated based on their IR spectra. The most striking differences between MCF-7 and NCI/ADR were found in features assigned to CH2 and CH3 stretching vibrations of lipid acyl chains and PO2 stretching vibrations of nucleic acids. To assess the potential of IR spectroscopy for the diagnosis of breast tumor tissues, thin sections of tissue were mapped by FTIR microspectroscopy. The spectra of these maps were analyzed using functional group mapping techniques and cluster analysis, and the output values of the different approaches were then reassembled into IR images of the tissue. A comparison of the IR images with the standard light microscopic images of the corresponding areas suggested that: (i) chemical mapping based on single band intensities is an easy way to detect microscopic fat droplets within tissue; (ii) the comparison of IR images based on band intensities at 1054 and 1339 cm-1 provides information on tissue areas containing tumor cells; (iii) cluster analysis of the spectra is superior to the single band approach and more appropriate for differentiation between tissue types.NRC publication: Ye
VIBRATIONAL CIRCULAR DICHROISM STUDIES OF CYCLOSPORINS
No full text1. R. A. Shaw, H. H. Mantsch, and B. Z. Chowdhry, Can. J. Chem. 71, 1334 (1993). 2. R. A. Shaw, H. H. Mantsch, and B. Z. Chowdhry, Int. J. Bio. Macromol. 16, 143 (1994).Author Institution: Syracuse University, NY 13244The conformations of cyclosporin A (CsA) and cyclosporin analogs CsC, CsD, and CsH, in chloroform solution, have been investigated by using infrared and vibrational circular dichroism (VCD) spectroscopies Cyclosporin A is a cyclic undecapeptide, which serves as an immunosuppressive drug. The analogs differ at residue 2 or 11. In the NH-stretching region, intense negative VCD features are observed for CsA and CsD, indicative of strong hydrogen-bonded -sheet and -turn structures. Features in this region are much weaker for CsH and CsC, indicative of altered intermolecular hydrogen-bonding interactions when the chiral center at residue 11 is inverted (CsH), or when an OH group is added at residue 2 (CsC). These studies extend earlier FT-IR investigations of $cyclosporins.^{1,2}
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The Pierre Auger project
Get PDFThe Pierre Auger project is a broadly based international effort to make a detailed study of cosmic rays at the highest energies. Two air shower detectors are proposed, one to be placed in the Northern Hemisphere and one in the Southern Hemisphere. Each installation will consist of an array of 1600 particle detectors spread over 3000 km{sup 2} with a solid angle acceptance of 2 sr for cosmic ray air showers. Eah installation will also have an atmospheric fluorescence detector viewing the volume above the surface array. These two air shower detector techniques working together form a powerful instrument for the proposed research. The objectives of the Pierre Auger project are to measure the arrival direction, energy, and mass composition of 60 events per year above an energy of 10{sup 20} eV and 6000 events per year above 10{sup 19} eV. A collaboration is now being formed with the goal of having the Pierre Auger observatory in operation by 2001
Detection and grading of human gliomas by FTIR spectroscopy and a genetic classification algorithm
No full textPeer reviewed: YesNRC publication: Ye
Conformation and self-association of the peptide hormone substance P : Fourier-transform infrared spectroscopic study
No full textFourier-transform i.r. (f.t.i.r.) spectroscopy has been applied to the study of the conformational properties of substance P in aqueous solution. Spectra were obtained in the presence of lipid membranes and Ca2+ to assess the role of these factors in induction of the active conformation of the peptide. In aqueous solution substance P was found to be predominantly unstructured at physiological p2H, where the lack of long-range order is probably related to charge repulsion along the peptide chain. However, substance P aggregated in aqueous solution at p2H > 10.0. Little or no induction of secondary structure was seen on addition of the peptide to negatively charged bilayers, suggesting that interaction with a membrane surface does not play an important role in the stabilization of the active conformation of the peptide. In fact, substance P was found to aggregate in the presence of charged lipids, which would tend to hinder rather than enhance interaction with the receptor. We propose a model for the aggregation of substance P at the bilayer surface, based on our studies of the effect of p2H and lipid/peptide ratio on spectra. Addition of Ca2+ had no effect upon the secondary structure of the peptide or on its interactions with membranes.Peer reviewed: YesNRC publication: Ye
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Prospects for 6 to 10 tesla magnets for a TEVATRON upgrade
No full textThe first SSC physics is at least 10 years away. An upgrade of the Fermilab Tevatron will ensure the continuity of a vigorous high-energy physics program until the SSC turns on. Three basic proposals are under consideration: /bar p/p at 3 /times/ 10/sup 31/ --Increase luminosity by improvements to the p source. pp at 1 TeV and 2 /times/ 10/sup 32/--Move the main ring to a new tunnel, build a second Tevatron ring, and /bar p/p > 1.5 TeV and 7 /times/ 10/sup 30/--Replace the tevatron with a higher energy ring. The last two options requires about a hundred 6.6-tesla dipoles in addition to a ring of Tevatron strength (4.4 T) magnets. These higher-field magnets are necessary in both rings to lengthen the straight sections in order to realize the collision optics. The third option requires a ring of magnets of 6.6 T or slightly higher to replace the present Tevatron plus a number of special 8--9 tesla magnets. The viability of the high-energy option then depends on the practicality of sizable numbers of reliable 8--9 tesla dipoles as well as 800 6.6-tesla dipoles. The following develops a specification for an 8.8 T dipole, examines the design considerations and reviews the current state of high-field magnet development. 22 figs., 3 tabs
A deuterium NMR study of molecular dynamics and geometry in two classes of onium salts:(CH3) 3E+ X-and C6H5M (CH3) 3+ I
No full textDeuterium NMR measurements are reported for two types of onium salts: (CH3)3E+I-, where E = O (counterion is BF4-), S, Se, or Te, and C6H5M(CH3)3+I-, where M = N, P, or As. Within each class of compounds the activation energy for rotation of the trimethyl groups about the C3' axis increases with increasing size of the central atom. In the first class of compounds the C-E-C bond angle decreases with the size of the atom E. In addition the magnitude of the quadrupolar coupling constant, chi, varies with E, ranging from 160 kHz for E = O to 190 kHz for E = Te. This is in qualitative agreement with molecular orbital calculations of the electric field gradients. At low temperatures the H-2 NMR spectrum of C6H5N(CH3)3+I- Can only be rationalized with a model in which trimethyl rotation is faster than methyl rotation. The H-2 NMR of ring (predominantly ortho and para)-deuterated C6H5N(CH3)3+I- is consistent with rapid n-site (n greater-than-or-equal-to 3) rotation of the phenyl ring above 390 K. Below 390 K spectra characteristic of two-site, 180-degrees, flips of the phenyl ring are observed. Below 280 K the motion of the phenyl ring is in the rigid lattice limit.PT: J; CR: COLLINS MJ, 1988, J AM CHEM SOC, V110, P8583 DAVIS JH, 1976, CHEM PHYS LETT, V42, P390 DAVIS JH, 1991, ISOTOPES PHYSICAL BI, V3 EINSTEIN F, 1967, J CHEM SOC A, P2018 FECHER G, 1986, BER BUNSEN PHYS CHEM, V90, P10 FISCH MJ, 1990, GAUSSIAN 90 FURUKAWA Y, 1989, Z NATURFORSCH A, V44, P112 GREENFIELD MS, 1987, J MAGN RESON, V72, P89 GRIFFIN RG, 1981, METHOD ENZYMOL, V72, P108 GRUWEL MLH, 1990, Z NATURFORSCH A, V45, P55 HAYS GR, 1978, THESIS U E ANGLIA HIROKAWA K, 1988, Z NATURFORSCH A, V43, P187 HOPE H, 1966, ACTA CRYSTALLOGR, V20, P610 IKEDA R, 1989, J PHYS CHEM-US, V93, P7315 ISHIDA H, 1989, Z NATURFORSCH A, V44, P741 ISHIDA H, 1991, Z NATURFORSCH A, V46, P265 KOBAYASHI A, 1988, Z NATURFORSCH A, V43, P233 KORFER M, 1989, Z NATURFORSCH A, V44, P1177 KRUG V, 1989, ACTA CRYSTALLOGR C, V45, P2022 LAMBERT JB, 1968, J AM CHEM SOC, V90, P1349 MANTSCH HH, 1977, PROG NUCL MAG RES SP, V11, P211 MOOIBROEK S, 1988, CAN J CHEM, V66, P734 MOOIBROEK S, 1989, CAN J CHEM, V63, P2926 OLAH GA, 1984, J ORG CHEM, V49, P2112 PALMER MH, 1986, Z NATURFORSCH A, V41, P1471 PALMER MH, 1990, Z NATURFORSCH A, V45, P357 PENNER GH, 1992, CAN J CHEM, V70, P2420 PENNER GH, 1992, J PHYS CHEM-US, V96, P5121 PETTITT BA, 1981, J MAGN RESON, V44, P508 RATCLIFFE CI, 1979, FARADAY DISC CHEM SO, V13, P142 RATCLIFFE CI, 1986, CAN J CHEM, V64, P1348 RATCLIFFE CI, 1990, J PHYS CHEM-US, V94, P152 RIPMEESTER JA, 1987, DYNAMICS MOL CRYSTAL SCHWARTZ LJ, 1983, J PHYS CHEM-US, V87, P4457 SPIESS HW, 1985, ADV POLYM SCI, V66, P23 THOMAS AF, 1971, DEUTERIUM LABELING O TSAU J, 1970, CAN J CHEM, V48, P717 VEGA AJ, 1987, J CHEM PHYS, V86, P1803 WATKINS MI, 1982, J AM CHEM SOC, V104, P2365 WITTEBORT RJ, 1987, J CHEM PHYS, V86, P5411 XU Q, 1991, Z NATURFORSCH A, V46, P240 ZUCCARO DE, 1959, Z KRISTALLOGR, V112, P26; NR: 42; TC: 6; J9: CAN J CHEM; PG: 10; GA: LC512Source type: Electronic(1
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