Library

X
Your search history is empty.
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Characterization of Agonist-Induced Down-Regulation of NMDA Receptors in Cerebellar Granule Cell Cultures (1996)
    Oxford, UK : Blackwell Science Ltd
    Journal of neurochemistry 66 (1996), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: Exposure of cerebellar granule cells to NMDA in culture at 5 days in vitro, when cells are not yet vulnerable to NMDA, evoked a pronounced reduction in NMDA receptor activity, measured by NMDA-induced 45Ca2+ influx, and counteracted the normal developmental increase in NMDA receptors. The effect was concentration and time dependent, the half-maximal effect being reached at about 45 µM and by 4–5 h. The decrease in NMDA receptor function was accompanied by a significant reduction in the protein level of the obligatory NMDA receptor subunit (NR) NR1. Both parameters remained at a low level as long as the agonist was present. However, receptor down-regulation was reversible, as receptor protein levels and NMDA responses were restored to control values upon NMDA removal, this process requiring protein synthesis. NMDA treatment also elicited a decrease in NR1, NR2A, and NR2B subunit messenger RNA (mRNA) levels. However, in comparison with NMDA receptor proteins, the decrease was faster, and NMDA receptor mRNA content recovered to control levels within 24 h in spite of the presence of NMDA. Concerning the mechanisms of agonist-induced regulation of NMDA receptor expression, it seems that protein kinase C-mediated protein phosphorylation is not involved, whereas inhibition of Ca2+/calmodulin-dependent kinase II/IV by KN-62 does depress NMDA receptor expression even in the absence of NMDA.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1471-4159.1996.66010369.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    GaAs pattern etching with little damage by a combination of Ga+focused-ion-beam irradiation and subsequent Cl2 gas etching (1990)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 68 (1990), S. 6415-6419 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Pattern formation on GaAs by Ga+ focused-ion-beam (FIB) irradiation and subsequent Cl2 gas etching was carried out. A higher etch rate at the FIB-irradiated area compared with that not irradiated under Cl2 gas allows pattern construction without a mask process. The degree of residual crystal damage was evaluated using photoluminescence (PL) intensity measurements. The PL intensity in the etched region was one order of magnitude stronger than that of FIB sputtering, and was several times stronger than that of Ga+ FIB-assisted Cl2 etching. Etch depths of the order of 100 nm, which is five times deeper than that obtained by FIB sputtering, were efficiently performed using moderate Ga+-ion doses.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.346862
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Electron-beam-induced pattern etching of AlGaAs using an ultrathin GaAs oxide as a resist (1990)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 68 (1990), S. 3630-3634 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Electron-beam (EB)-induced pattern etching of AlxGa1−xAs (0≤x≤0.7) is described. An ultra-thin GaAs oxide at the surface of a GaAs/AlGaAs heterostructure wafer is used as a resist film. The GaAs oxide resist can be selectively removed by EB irradiation in a Cl2 ambient, which results in pattern etching of GaAs/AlGaAs. The etch rate of AlGaAs is examined as functions of substrate temperature, AlAs mole fraction, and EB flux. The results indicate that pattern etching is realized in the AlAs mole fraction range of 0≤x≤0.7
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.346325
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Novel electron-beam lithography for in situ patterning of GaAs using an oxidized surface thin layer as a resist (1990)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 67 (1990), S. 4297-4303 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The first demonstration of in situ electron-beam (EB) lithography is reported, where a photo-oxidized surface thin layer of GaAs is used for a resist. The in situ EB lithography sequence consists of five processes, i.e., preparation of a clean GaAs surface, photo-oxidation for a resist film formation, direct patterning of the oxide resist by EB-induced Cl2 etching, Cl2 gas etching of GaAs surface for pattern transfer, and thermal treatment in an arsenic ambient for resist removal and surface cleaning. The GaAs wafer is never exposed to air throughout all of the above processes to avoid an unintentional surface contamination. The minimum electron dose required for patterning of the GaAs oxide resist is about 5×1016 cm−2. An overgrown layer on the patterned GaAs surface shows a good surface morphology, which strongly indicates that this technology makes it possible to repeat crystal growth and surface patterning.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.344945
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Reduction of induced damage in GaAs processed by Ga+ focused-ion-beam-assisted Cl2 etching (1990)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 68 (1990), S. 2392-2399 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Damage in GaAs induced by Ga+ focused-ion-beam-assisted Cl2 etching is studied by photoluminescence (PL) intensity measurements as functions of ion energy, ion dose, and substrate temperature. By decreasing the ion energy from 10 to 1 keV, the damage depth decrease to 1/5, where damage depth is taken as the thickness at which the PL intensity recovers by wet etching. The damage depth is shallower when the etching yield is larger with the same ion energy. By increasing the ion dose, the normalized PL intensity decreases, but damage depth is nearly constant. Over 1015 ion dose, the normalized PL intensity shows a constant value. By increasing the sample temperature, the damage depth becomes shallower. At 150 °C with ion energy of 1 keV, the damage depth is less than 0.5 μm, which is the detection limit of the PL measurement in GaAs substrate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.346497
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Submicron pattern etching of GaAs by in situ electron beam lithography using a pattern generator (1990)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 57 (1990), S. 1012-1014 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Pattern etching of GaAs at submicron size is carried out by in situ electron beam (EB) lithography using a computer-controlled pattern generator. GaAs oxide on the wafer surface is used as a resist film in EB-induced Cl2 etching. A 0.5 μm linewidth in a 1 μm pitch line-and-space pattern with flat top surface is obtained. Observations of the pattern edge with a scanning electron microscope show that the boundary between the etched area and the oxide mask area is abrupt and that the undulation of the pattern edge is less than about 30 nm.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.103551
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Photo-oxidation of GaAs for in situ patterned-mask formation prior to chlorine gas etching (1990)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 56 (1990), S. 98-100 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: This is the demonstration of "in-situ masking'' concept. In situ patterning of GaAs is carried out by using a photo-oxidized surface layer as a mask for subsequent Cl2 etching. Clean GaAs surface provided by molecular beam epitaxy is exposed to pure oxygen and is simultaneously irradiated with an Ar+ ion laser of the 514.5 nm line for photo-oxidation of the surface. Subsequent Cl2 gas etching of the photo-oxidized sample reveals that the GaAs oxide fills the role of an etching mask. The resistance of the oxide mask against Cl2 etching varies depending on the laser fluence with which the oxide of GaAs is formed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.102616
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    In situ patterning and overgrowth for the formation of buried GaAs/AlGaAs single quantum-well structures (1992)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 60 (1992), S. 365-367 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Buried GaAs/AlGaAs single quantum-well structures have been fabricated for the first time by in situ electron beam (EB) lithography. The process includes the molecular beam epitaxy of a GaAs/AlGaAs single quantum well, electron-beam direct writing, Cl2 gas etching, and overgrowth of an AlGaAs layer. A thin GaAs oxide layer was used as the etching mask, which was selectively formed on a clean GaAs surface by EB irradiation under an O2 ambient. Subsequent Cl2 gas etching resulted in the formation of isolated quantum wells. Prior to the overgrowth, thermal cleaning with atomic hydrogen was employed for removing the oxide mask. The cathodoluminescence image of the buried quantum well demonstrates the high quality of the resultant structure formed by in situ EB lithography.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.106658
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    CYCLIC NUCLEOTIDE PHOSPHODIESTERASE OF HUMAN CEREBROSPINAL FLUID (1975)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 25 (1975), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract— Cyclic 3′,5′-AMP (cAMP) and cyclic 3′,5′–GMP (cGMP) phosphodiesterase activities were found in human cerebrospinal fluid (CSF) using low substrate concentration (0.4μM). More rapid hydrolysis of cGMP than that of cAMP was observed in human CSF. However, cGMP hydrolytic activity of CSF was very much lower (0.3 pmol/min/ml CSF) than that of human cerebral cortex (33.7 nmol/min/g wet cortex). The pH optimum was found to be 8.0 (cGMP phosphodiesterase) and 7.5 (cAMP phosphodiesterase). The maximum stimulation of both cAMP and cGMP phosphodiesterase was achieved at 4 mM-MgCl2. Cyclic AMP had relatively little effect on the hydrolysis of cGMP in CSF and the cortex, while cGMP inhibited hydrolysis of cAMP in both tissues. Snake venom was found to stimulate cAMP and cGMP phosphodiesterase activity of CSF, by 60% and 110% respectively. This stimulation by snake venom was also observed in the cortex phosphodiesterase, but was not observed in human plasma or thyroid phosphodiesterase. When CSF was applied to Sepharose 6B column, cGMP phosphodiesterase was separated into three different molecular forms. A plot of activity against substrate concentration using peak I (largest molecular size) revealed a high affinity (Km= 2.6μM) and a low affinity (Km= 100μM) for cAMP suggesting the existence of at least two molecular forms of the enzyme. On the other hand, using a cGMP as substrate the only one Km value (1.90 μm) was obtained. These Km values of CSF enzymes described above were close to those obtained from human cerebral cortex preparations. The enzyme under peak I corresponded to the cortex enzyme when judged from its molecular size and stimulation by snake venom. It seems likely from our results that at least a part of CSF phosphodiesterase originates from the central nervous system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1471-4159.1975.tb07692.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    OCCURRENCE OF A SEROTONIN SULPHOTRANSFERASE IN THE BRAIN (1969)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 16 (1969), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract— —An enzyme catalysing the transfer of sulphate from 3′-phosphoadenylsulphate to serotonin was purified from rabbit brain. The purification procedure involved ammonium sulphate fractionation of the 200,000 g supernatant of rabbit brain homogenate, treatment with alumina Cγ, and chromatography on DEAE-cellulose. The enzyme was purified 67-fold from the 200,000 g supernatant of the brain homogenate. The intracranial distribution of the sulphotransferase was investigated and the cerebellum found to have rather high activity. The sulphotransferase activities of rabbit, dog, rat and bovine brains were compared; rabbit brain had the highest activity, followed by dog, rat and bovine brain.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1471-4159.1969.tb06457.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...