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  • 1
    Electronic Resource
    Electronic Resource
    High-pressure NMR probes for the in situ investigation of gas/liquid reactions (1992)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 63 (1992), S. 3307-3310 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Three different types of nuclear magnetic resonance (NMR) probes have been developed for investigating multiple phase (gas/liquid) reactions in situ at ambient and high pressure. Versions requiring only minimal modifications of existing NMR probes, low volume probes, and high precision flow systems have been optimized for specific boundary conditions. Pressures ranging from 1 to 20 bar have been successfully applied. The arrangements are especially attractive for the in situ investigations of homogeneous hydrogenation reactions displaying nuclear spin polarization.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1142543
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  • 2
    Electronic Resource
    Electronic Resource
    Experimental Archaeology: Investigation on the Copper–Aluminum–Silicon–Oxygen System (2002)
    Westerville, Ohio : American Ceramics Society
    Journal of the American Ceramic Society 85 (2002), S. 0 
    Details
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The behavior of the Cu-Al-Si-O system was investigated in the temperature range of 800°–1150°C. X-ray diffraction, infrared spectroscopy, diffusive reflectance, and electron microscopy were applied to obtain information about the influence of sintering, crystallization, and chemical reaction, each of which determines the color of the material. Definition of the artificial term “engobe,” opposite to the term “glaze,” was possible using copper(II) oxide (CuO) as its indicator. The detected chemical processes render possible explanations about the traditional way of ceramic painting during the 16th century and support the knowledge transfer from the viewpoint of history and that of natural science, as attempted by “archaeometry.”
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.2002.tb00369.x
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  • 3
    Electronic Resource
    Electronic Resource
    Activation of Zn and Cd acceptors in InP grown by metalorganic vapor phase epitaxy (1989)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 54 (1989), S. 2411-2413 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have investigated the activation by post-deposition annealing of Zn and Cd acceptors incorporated in InP during epitaxial growth using metalorganic vapor phase epitaxy. Growth was carried out at 20 mbar and atmospheric pressure for Zn- and Cd-doped samples, respectively, using TMI, PH3, DEZn, and DMCd as sources. Post-epitaxial annealing in a N2 atmosphere at temperatures in the range of 370–470 °C leads to complete activation of the acceptors. This process is strongly temperature dependent and a distinct effect of a GaInAs overlayer was observed. The activation energy is the same for Zn- and Cd-doped samples. It is suggested that the diffusion of vacancies plays a determining role in activating the dopant.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.101091
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  • 4
    Electronic Resource
    Electronic Resource
    Doping of InP and GaInAs during organometallic vapor-phase epitaxy using disilane (1988)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 63 (1988), S. 2874-2876 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Disilane (Si2H6) is presented as a new silicon doping source in the organometallic vapor-phase epitaxy of InP and GaInAs. The doping characteristics of disilane were studied under a range of growth conditions used to obtain device quality layers. Silicon incorporation by means of disilane shows a different behavior in InP and GaInAs doping. The slope of the log N vs log (disilane flow) plot is 0.75 for InP and 1 for GaInAs. A variation of doping level with growth temperature was observed revealing an activation energy of 1.2 eV in the case of InP. Electrical measurements on disilane-doped InP and GaInAs yield the same high mobilities as obtained in otherwise doped films, indicative of low compensation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.340945
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  • 5
    Electronic Resource
    Electronic Resource
    INCORPORATION OF 32P INTO THE PHOSPHOLIPIDS OF NEURONAL AND GLIAL CELL ENRICHED FRACTIONS ISOLATED FROM RABBIT CEREBRAL CORTEX: EFFECT OF NOREPINEPHRINE (1974)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 23 (1974), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract— Glial cells isolated from rabbit cerebral cortex contained approximately one-third more phospholipids per unit protein than the neuronal cell bodies. The pattern of individual phospholipids was rather similar in both cell types. The incorporation of intracisternally administered 32P into neuronal and glial phospholipid classes of rabbit brain was studied at intervals ranging from 5 to 60min. In general, for all investigated phospholipids the incorporation of the label was somewhat faster in neurons than in glial cells. Phosphatidylinositol showed the fastest and ethanolamine plasmalogen the slowest incorporation of 32P in both neurons and glial cells. A lag phase of about 10 min could be observed before labelling of the glial phosphatidylcholine, phosphatidylethanolamine, ethanolamine plasmalogen, phosphatidylserine and sphingomyelin had occurred. Among the neuronal phospholipids a lag phase was found only for the labelling of the ethanolamine plasmalogen. Norepinephrine increased the incoropration of 32P into phosphatidylinositol of both glia and neurons but had no effect on the specific radioactivity of ethanolamine plasmalogen and sphingomyelin. Labelling of phosphatidylcholine was slightly inhibited in both cell types by the administration of norepinephrine.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1471-4159.1974.tb10758.x
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  • 6
    Electronic Resource
    Electronic Resource
    THE SYNTHESIS OF CHOLINE AND ETHANOLAMINE PHOSPHOGLYCERIDES IN NEURONAL AND GLIAL CELLS OF RABBIT IN VITRO (1973)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 21 (1973), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract— The de novo synthesis of phosphatidylcholine and phosphatidylethanolamine in isolated neuronal and glial cells from adult rabbit brain cortex was investigated in vitro, using labelled phosphorylcholine (phosphorylethanolamine) or cytidine-5′-phosphate choline (cytidine-5′-phosphate ethanolamine), as lipid precursors. Synthesis of phospholipid from phosphorylcholine and phosphorylethanolamine in both fractions was extremely low when compared to that derived from the corresponding cytidine nucleotides. The neuronal cell-enriched fraction was found to possess a much higher rate of synthesis of both lipids from all precursors. Neuronal/glial ratios of about 5–9 were found for the synthesis of phosphatidylcholine and phosphatidylethanolamine from cytidine-5′-phosphate choline and cytidine-5′-phosphate ethanolamine, respectively. Several kinetic properties of the choline-phosphotransferase (EC 2.7.8.2) and ethanolaminephosphotransferase (EC 2.7.8.1) were found to be similar both in neurons and in glia (e.g. Km of cytidine-5′-phosphate ethanolamine, Km of diacyl glycerol, pH optimum, need for divalent cations), but the Km value for cytidine-5′-phosphate choline in glial cells was much lower (2.3 × 10−4m) than in neurons (1 × 10−3m). The Kmfor cytidine-5′-phosphate ethanolamine in both cells was much lower than in whole brain microsomes. It is concluded that the cytidine-dependent enzymic system for phosphatidylcholine and phosphatidylethanolamine synthesis is concentrated mostly in the neuronal cells, as compared to glia.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1471-4159.1973.tb07561.x
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  • 7
    Electronic Resource
    Electronic Resource
    PHOSPHOLIPID METABOLISM IN EXPERIMENTAL ALLERGIC ENCEPHALOMYELITIS: ACTIVITY OF MITOCHONDRIAL PHOSPHOLIPASE A2 OF RAT BRAIN TOWARDS SPECIFICALLY LABELLED 1,2-DIACYL-, 1-ALK-1′-ENYL-2-ACYL- AND 1-ALKYL-2-ACYL-SN-GLYCERO- 3-PHOSPHORYLCHOLINE (1974)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 23 (1974), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: —1,2-Diacyl-, 1-alk-1′-enyl-2-acyl-and 1-alkyl-2-acyl-sn-glycero-3-phosphorylcholine, specifically labelled with different fatty acids at the 2 position, were prepared enzymically using the acyltransferase system of rabbit sarcoplasmic reticulum. The substrates were submitted to hydrolysis by mitochondrial phospholipase A2 (phosphatide acyl-hydrolase, EC 3.1.1.4) obtained from normal and from rat brain afflicted with EAE. In the acute stage of the disease an increase of approximately 25 per cent in phospholipase A 2 activity could be observed in comparison to that from the control animals for all investigated substrates. Phospholipase A2 obtained from normal rat brains and from those afflicted with EAE had a higher affinity for 1,2-diacyl-sn-glycero-3-phosphorylcholine when compared to the corresponding alkyl acyl- and alkenyl acyl-analogues. Choline plasmalogen was cleaved more slowly than the corresponding alkyl acyl derivative. The enzyme activity returned to the control level in the recovery stage of the demyelinating disease.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1471-4159.1974.tb04399.x
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  • 8
    Electronic Resource
    Electronic Resource
    Occurrence and Properties of Phospholipases A1 of Plasma Membranes Prepared from Neuronal- and Glial-Enriched Fractions of the Rabbit Cerebral Cortex (1981)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 36 (1981), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: Exogenously added glycerophosphatides, specifically radioactively labelled either in the 1 or in the 2 position, were used to investigate the occurrence and properties of phospholipase A1 in plasma membranes prepared from neuronal- and glial-enriched fractions of rabbit brain. Phospholipase A1 activity was maximal at pH values ranging between 8.0 and 9.0 for the plasma membranes of both cell types. The enzyme activity was most abundant in the microsomal fraction, with a neurondglial ratio of about 2. The plasma membranes displayed about half the enzymic activity of the microsomal fraction, whereas only small amounts of phospholipase A1 were present in the neuronal and glial mitochondria. Investigations on the substrate specificity showed a different pattern for the enzyme of neuronal and glial origin. The release of labelled fatty acids from phosphatidylcholine by the neuronal plasma membrane phospholipase A1 decreased with increasing degree of unsaturation of the fatty acids at the 1 position. The presence of plasmalogens and plasmalogen precursors in the incubation mixture appreciably inhibited the hydrolysis of the corresponding diacyl compounds.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1471-4159.1981.tb01675.x
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  • 9
    Electronic Resource
    Electronic Resource
    THE METABOLISM OF LABELLED CHOLINE IN NEURONAL AND GLIAL CELLS OF THE RABBIT IN VIVO (1977)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 28 (1977), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: [Methyl-3H]choline has been injected intraventricularly into adult rabbits, and the rate of synthesis of phosphatidylcholine, choline plasmalogen and sphingomyelin (and their hydrosoluble precursors) in isolated neuronal and glial cells has been investigated. At all time intervals examined, the injected radioactivity was incorporated only into the base moiety of the choline lipids in both cell types. Maximum labelling of the two choline phosphoglycerides occurred in neurons 150 min after administration, whereas the highest specific radioactivity for glial phosphatidylcholine and choline plasmalogen was reached at 6 and 10 h, respectively. At any time interval examined, the neuronal and glial choline plasmalogen displayed a higher specific radioactivity than the corresponding diacyl-derivative. The two phosphoglycerides incorporated the base in both cell populations at a faster rate than did whole brain tissue. Sphingomyelin was labelled in both cells at a low rate and acquired measurable radioactivity levels only after 2 h from isotope administration.Highest levels of radioactivity for phosphorylcholine and cytidine-5′-diphosphocholine were reached in both neurons and glia 1-2 h after administration, but these levels per unit protein were higher in glial than in neuronal cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1471-4159.1977.tb07723.x
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  • 10
    Electronic Resource
    Electronic Resource
    PHOSPHOLIPID METABOLISM IN SUBACUTE SCLEROSING PANENCEPHALITIS : ACTIVITY OF BRAIN PHOSPHOLIPASE A2 TOWARDS SPECIFICALLY LABELLED 1,2-DIACYL-, 1-ALK-1′-ENYL-2-ACYL- AND 1-ALKYL-2-ACYL-sn-GLYCERO-3-PHOSPHORYLCHOLINE (1976)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 26 (1976), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: —1,2-Diacyl-, 1-alk-1′-eny1-2-acyl- and 1-alky1-2-acyl-sn-glycero-3-phosphorylcholine specifically labelled with different fatty acids at the 2 position, were prepared enzymically using the acyltransferase system of rabbit sarcoplasmic reticulum. The substrates were submitted to hydrolysis by phospholipase A2 (phospholipid acyl-hydrolase, EC 3.1.1.4) obtained from normal and brain tissue affected with subacute sclerosing panencephalitis. In the diseased tissue an increase of phospholipase A2 activity ranging from 46 to 54% could be observed in comparison to the control brain for all substrates investigated. Among the investigated substrates phospholipase A2 had the highest affinity for the 1,2-diacylcompound, whereas alkenylacyl- and alkylacyl-sn-glycero-3-phosphorylcholine were cleaved at almost similar rates. The hydrolysis rate of choline-plasmalogen and the corresponding diacyl compound by the enzyme was greatly influenced by the fatty acid moiety located at the 2 position of the substrates.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1471-4159.1976.tb04476.x
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