Library

X
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
    Linear optical properties of a heavily Mg-doped Al0.09Ga0.91N epitaxial layer (1999)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 74 (1999), S. 3188-3190 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The room-temperature absorption coefficient and ordinary refractive index for a ∼0.4-μm-thick p-type wurtzite Al0.09Ga0.91N epitaxial layer were determined via optical transmission measurements. The layer was grown by metal organic chemical vapor deposition and heavily doped (∼5×1019 cm−3) with Mg. Additional measurements of the refractive index by prism coupling to the layer confirmed the transmission results. The low-temperature AlN buffer layer altered the expected interference fringes of the transmission spectrum below the band-gap energy and had to be accounted for in the analysis. The absorption coefficient exhibited band-tail effects and had a reduced slope near band-gap energy as compared to undoped GaN. Using a detailed balance argument, the reduced slope was consistent with the lack of a peak in the continuous-wave photoluminescent emission. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.124102
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Optical-field calculations for lossy multiple-layer AlxGa1−xN/InxGa1−xN laser diodes (1998)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 84 (1998), S. 1196-1203 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Optical-field profiles in wide-band-gap AlxGa1−xN/InxGa1−xN multiple-quantum well (MQW) separate-confinement heterostructure (SCH) laser diodes (LDs) were calculated using a 2×2 transfer-matrix approach that accommodates complex refractive indices. The refractive indices of AlxGa1−xN and InxGa1−xN were approximated by shifting the refractive index of GaN according to the band-gap energy of the solid solution. Current LDs were analyzed and show reasonable optical confinement. Optimization of the SCH waveguide for a three MQW active region was performed by varying the waveguide and cladding layer thicknesses. For 0.8μm thick Al0.10Ga0.90N cladding layers, waveguides on sapphire and SiC substrates had a maximum confinement factor of ∼3.3%. Layers outside of the waveguide strongly affected the optical field for thin (∼0.4 μm) cladding layer thicknesses and resulted in resonant coupling of the light out of the waveguide. Sapphire substrates were found to enhance light confinement, while SiC substrates were found to reduce optical confinement as the cladding layer thickness is reduced. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.368185
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Ordinary and extraordinary refractive indices for AlxGa1−xN epitaxial layers (1999)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 75 (1999), S. 67-69 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Dispersion of the ordinary and extraordinary indices of refraction for wurtzite AlxGa1−xN epitaxial layers with x=0.00, 0.04, 0.08, 0.11, and 0.20 in the range of wavelengths 457〈λ〈980 nm were measured via a prism-coupled waveguide technique. The quantitative accuracy of x is ±10% and the accuracy of the refractive indices is ∼±0.01. The dispersion is found to be well described by a 1st-order Sellmeier dispersion formula. A simple functional form is presented that allows calculation of the refractive indices as functions of x and λ. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.124278
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Ultrastructural Evidence for Transport of Protein across the Epithelium of the Rat Caput Epididymidis (1987)
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 513 (1987), S. 0 
    Details
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1749-6632.1987.tb25099.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Colloid cysts of the third ventricle: an immunohistochemical study (1992)
    Oxford, UK : Blackwell Publishing Ltd
    Histopathology 21 (1992), S. 0 
    Details
    ISSN: 1365-2559
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Eleven colloid cysts of the third ventricle were investigated by immunohistochemistry using 16 mono- and polyclonal antibodies. Colloid cyst epithelium, choroid plexus epithelium and ependyma showed different immunohistochemical profiles. In particular, antibodies to different cytokeratins and to transthyretin revealed considerable and constant differences of immunoreactivity. Therefore, common derivation of the three tissues seems unlikely. Our findings are interpreted in favour of the non-neuroepithelial origin of third ventricular colloid cysts.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2559.1992.tb00340.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Differential Expression of Synaptophysin and Synaptoporin During Pre- and Postnatal Development of the Rat Hippocampal Network (1994)
    Oxford, UK : Blackwell Publishing Ltd
    European journal of neuroscience 6 (1994), S. 0 
    Details
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The closely related synaptic vesicle membrane proteins synaptophysin and synaptoporin are abundant in the hippocampal formation of the adult rat. But the prenatal hippocampal formation contains only synaptophysin, which is first detected at embryonic day 17 (E17) in perikarya and axons of the pyramidal neurons. At E21 synaptophysin immunoreactivity extends into the apical dendrites of these cells and in newly formed terminals contacting these dendrites. The transient presence of synaptophysin in axons and dendrites suggests a functional involvement of synaptophysin in fibre outgrowth of developing pyramidal neurons. Synaptoporin expression parallels the formation of dentate granule cell synaptic contacts with pyramidal neurons: the amount of hippocampal synaptoporin, determined in immunoblots and by synaptoporin immunostaining of developing mossy fibre terminals, increases during the first postnatal week. Moreover, in the adult, synaptoporin is found exclusively in the mossy fibre terminals present in the hilar region of the dentate gyrus and the regio inferior of the cornu ammonis. In contrast, synaptophysin is present in all synaptic fields of the hippocampal formation, including the mossy fibre terminals, where it colocalizes with synaptoporin in the same boutons. Our data indicate that granule neuron terminals differ from all other terminals of the hippocampal formation by the presence of both synaptoporin and synaptophysin. This difference, observed in the earliest synaptic contacts in the postnatal hippocampus and persisting into adult life, suggests distinct functions of synaptoporin in these nerve terminals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1460-9568.1994.tb00569.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Rab3 Proteins and SNAP-25, Essential Components of the Exocytosis Machinery in Conventional Synapses, are Absent from Ribbon Synapses of the Mouse Retina (1996)
    Oxford, UK : Blackwell Publishing Ltd
    European journal of neuroscience 8 (1996), S. 0 
    Details
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: GTP-binding rab proteins, present in synaptic vesicles and endocrine secretory granules, have been shown to be involved in the control of regulated exocytosis. We found rab3 proteins in immunoblots of diverse areas of the mouse central nervous system (spinal cord, olfactory bulb, hippocampus, cerebellum and neocortex). Immunohistochemical observations at light- and electron-microscopical levels in the hippocampus and other areas revealed rab3 proteins in virtually all synaptic fields and terminals of the areas investigated. In the retina, rab3A immunoreactivity was confined to the inner and outer plexiform layers. Ultrastructural examination revealed that rab3A was present in conventional terminals in the inner plexiform layer and in horizontal cell processes of the outer plexiform layer. In contrast ribbon synapses, which play a key role in transferring information from the photoreceptor cells to the central nervous system, were immunonegative. We also tested whether other proteins of the rab3 family are present in ribbon synapses. However, using an antibody recognizing rab3B and rab3C in addition to rab3A, we found no immunoreactivity in these synapses. Interestingly, we observed also no immunoreactivity for synaptosomal-associated protein 25 (SNAP-25) in ribbon synapses, but conventional synapses and horizontal cell processes were heavily stained. Our data show that the known rab3 and SNAP-25 isoforms, which are components of the secretory apparatus of conventional synapses, are absent from ribbon synapses of the retina. Our observations suggest different mechanisms of transmitter exocytosis in conventional and ribbon terminals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1460-9568.1996.tb01177.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Ki-67 and biological behaviour in meningeal haemangiopericytomas (1996)
    Oxford, U.K. and Cambridge, USA : Blackwell Science Ltd
    Histopathology 29 (1996), S. 0 
    Details
    ISSN: 1365-2559
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The biological behaviour of meningeal haemangiopericytomas was retrospectively studied using immunohistochemical staining with MIB1, a monoclonal antibody against the Ki-67 antigen, a nuclear protein related to cell proliferation. Paraffin-embedded material from 62 tumours from 40 patients were investigated. The proliferating compartment of the tumours was estimated by evaluating the MIB1 staining index, i.e. the percentage of MIB1 positive nuclei in at least 1000 counted tumour cells in representative areas. The staining index ranged from 1.24% to 39.01%. Statistical analysis revealed no significant correlation between the staining index and recurrence-free survival (χ2 = 0.3922, P = 0.5311). Long-term observation (〉100 months), however, revealed a tendency to longer survival in the group with a staining index less than 5%. According to our results, the MIB1 staining index does not contribute to the accuracy of predicting the clinical outcome of meningeal haemangiopericytomas.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2559.1996.d01-479.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Fraction of H-bonded segments of N-ethylpyrrolidone, oligomeric and polymeric vinylpyrrolidone adsorbed from CHCl3 on silica measured by IR spectrometry (1985)
    Springer
    Colloid & polymer science 263 (1985), S. 372-380 
    Details
    ISSN: 1435-1536
    Keywords: Polymer adsorption ; IR spectrometry ; fraction of adhered segments ; silica
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The adsorption of N-ethylpyrrolidone (NEP), oligomeric and polymeric vinylpyrrolidone (OVP, PVP) on silica (Aerosil 200) from CHCl3 solution is investigated by IR spectrometry. The influence of the annealing temperature of the silica on the adsorbed amount and on the fraction of adhered segments was studied. The dependences of the amount adsorbed on solution concentration result for NEP in a Langmuir isotherm for OVP and PVP in high affinity isotherms. The fraction of adhered H-bridged carbonyl groups determined by compensation procedures, the fraction of surface SiOH groups occupied and the multiple interaction quotientQ show different dependences on the amount adsorbed for the measured adsorptives, indicating different interactions of the monomeric segments with the surface groups. This behaviour is explained by comparing the amount adsorbed in saturation with monolayer capacities, surface concentration of SiOH groups and frequency shifts. A splitting of the band of the bound carbonyl groups in a double peak was observed with OVP and PVP, referring to an additional interaction of polymer segments neighboured to specifically bound segments.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01410383
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Microcalorimetric studies of the adsorption of N-ethylpyrrolidone, oligomeric and polymeric vinylpyrrolidone from CHCl3 on silica (1985)
    Springer
    Colloid & polymer science 263 (1985), S. 381-387 
    Details
    ISSN: 1435-1536
    Keywords: polymer adsorption ; microcalorimetry ; enthalpy of adsorption ; fraction of adhered segments ; silica
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Adsorption enthalpies of N-ethylpyrrolidone, oligomeric and polymeric vinylpyrrolidone from CHCl3 solution on silica interfaces (Aerosil 200) have been measured at 25 °C by microcalorimetry. The dependence on surface coverage has been examined using measured adsorption isotherms. Binding enthalpies are calculated with fractions of adhered segments obtained by IR spectrometry and wetting enthalpies received from calorimetry. Fractions of adhered segments are derived from the adsorption enthalpies assuming equal binding enthalpies of monomers and polymer segments and considering desorption enthalpies of the solvent depending on the surface area of the polymer segments. The resulting enthalpies are compared with literature values from other solvents and the incongruity of the fraction of adhered segments obtained by IR, ESR, NMR and microcalorimetry is explained.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01410384
    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...