Library

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
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 54 (1989), S. 2336-2338 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have prepared Fe-doped InP epilayers by chemical beam epitaxy using a thermal atomic Fe beam. Epilayers having high resistivities ((approximately-greater-than)107 Ω cm) were obtained over a wide range of Fe concentrations. Resistivities as high as 1.3×108 Ω cm have been obtained. Such resistivity is almost equal to the theoretical value of 1.37×108 Ω cm that we estimate for intrinsic InP. The current-voltage characteristics exhibit both an ohmic and a space-charge-limited regime, and are consistent with the theory of single-carrier injection into a trap-free insulator. Pinning of the Fermi level near midgap by Fe-related deep levels is the mechanism by which the epilayer is made highly resistive. At room temperature, these traps are apparently deep enough that the carrier emission rate is negligible.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 16 (1969), S. 0 
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract— Purine and pyrimidine nucleotides were measured in the brain of normal and electroshocked rats after chromatographic separation on ion-exchange resin of mono-, di- and tri-phosphorylated derivatives.CMP, IMP and NAD did not show any significant quantitative change. Adenine nucleotides showed an abrupt change followed by a rapid return to the control value. GTP was the only purine nucleotide exhibiting a relatively slow return to its starting concentration. The greatest percentage increase after electroshock was observed in UMP, which returned to its control value only after 5 min; UDPCoenzymes (i.e. UDPA plus UDPG) showed a relatively small drop during the development of the seizure and the slowest return to the base line; UTP showed a late transistory increase above the normal level after an initial drop associated with convulsant activity.Tritiated uridine was injected intracisternally to investigate the turnover of pyrimidine nucleotides. UTP showed the highest specific radioactivity at the earliest time, followed by UMP, UDPCoenzymes and CMP. It was found that convulsant activity is associated with dramatic changes in the specific radioactivity of pyrimidine nucleotides.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    USA/Oxford, UK : Blackwell Science Ltd
    Cephalalgia 15 (1995), S. 0 
    ISSN: 1468-2982
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: We assessed the prevalence of migraine headaches in an epidemiological survey of an 11 to 14-year-old student population. Migraine headaches were classified on the basis of questionnaires and neurological examination using the operational diagnostic criteria of the International Headache Society. Prevalence of migraine without aura (IHS code 1.1) was 2.35%; that of migraine with aura (IHS code 1.2) was 0.62%. Migraine without aura was equally distributed among males and females, whereas migraine with aura was preponderant in the female cohort. The prevalence of migraine headaches in males was constant through the ages studied, whereas the prevalence of migraine headaches in females reached a peak at age 12 and plateaued over the following two years. Although the new IHS classification criteria of migraines are reliable and exhaustive, some subcriteria may not be valid in a juvenile population. For instance, the duration of the pain in young migraineurs is often briefer than in adults, and the intensity of pain was almost always described as moderate or severe. Therefore, in order to increase the reliability and comprehensiveness of the IHS classification, minor modifications should be made.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 1365-2133
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background  Lipoid proteinosis (LP), also known as Urbach–Wiethe disease, is a rare autosomal recessive disorder characterized by a hoarse voice, warty skin infiltration and scarring. Mutations within the extracellular matrix protein 1 (ECM1) gene cause LP.Objectives  We report the molecular analysis of the ECM1 gene in a Sicilian patient with LP in order to extend the mutation spectrum of this genodermatosis.Methods  We studied a 32-year-old female born from consanguineous parents who was diagnosed at the age of 11 years as having LP. She has a clinical phenotype corresponding to Urbach–Wiethe disease characterized by papules/nodules, indurated plaques and sometimes ulcerated lesions primarily involving the skin and mucous membranes, and extracutaneous features such as epilepsy, hoarseness of the voice and neuropsychiatric abnormalities. Samples of clinically affected skin obtained by biopsies were analysed after staining with haematoxylin and eosin, periodic acid–Schiff (PAS), and PAS–diastase. The whole ECM1 gene was analysed by direct sequencing.Results  We identified a homozygous nonsense mutation in exon 6 of the ECM1 gene, C589T (Q197Ter).Conclusions  Over 60% of mutations occur in exons 6 and 7. Exon 7 is alternatively spliced and frameshift mutations in exon 7 lead to ablation of the ECM1a transcript, but not the shorter ECM1b transcript that normally lacks this exon. Homozygous nonsense or frameshift mutations in exon 6 are predicted to affect both full-length ECM1a and ECM1b transcripts, whereas ECM1b should be unaffected for similar types of mutation in exon 7. It has been suggested that individuals with mutations in exon 7 have a slightly milder phenotype than those with exon 6 mutations. This is the first report with respect to a novel mutation of the ECM1 gene responsible for recessive LP in Sicily.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Neuropsychologia 12 (1974), S. 165-174 
    ISSN: 0028-3932
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Psychology
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 29 (1977), S. 107-122 
    ISSN: 1432-1106
    Keywords: Area 17 ; Lateral suprasylvian area ; Remote visual stimuli ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Single units were recorded extracellularly from area 17 and lateral suprasylvian area (LSSA) in curarized cats. Visual stimuli, usually a 10 ° black spot, were introduced abruptly in the visual field remote from the discharge area of a neuron's receptive field and moved at a speed of about 30 °/sec. The effect of these remote stimuli (S2) on the response to a restricted visual stimulus (S1) crossing the discharge area was studied. It was found that most units in area 17 were not affected by the presentation of remote stimuli, the remainder being either slightly facilitated or slightly inhibited. In contrast the LSSA neurons were usually inhibited by the presentation of S2: this effect was strong, was present in all classes of LSSA neurons and was independent of the relative directions of movement of S1 and S2. On the basis of these data and those previously obtained from the superior colliculus it is concluded that the way the extrageniculate centres respond to a stimulus abruptly introduced in the visual field is substantially different from that of the striate cortex. Only in the extrageniculate centres a new stimulus, besides exciting the neurons which correspond to the position of the stimulus in the field, concomitantly decreases the responses of neurons located in positions of the visual field remote from that stimulus. Possible behavioral implications of the findings are discussed.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 36 (1979), S. 191-194 
    ISSN: 1432-1106
    Keywords: Hypercomplex cells ; Area 18 ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Single unit recording has revealed the same orientation sensitive cell classes in cat area 18 as are to be found in area 17. These include particularly the various types of hypercomplex cell belonging to the S, C, and B cell families.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 38 (1980), S. 37-42 
    ISSN: 1432-1106
    Keywords: Superior colliculus ; Monkey ; Receptive field characteristics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Single neurons were recorded from the superficial layers of the superior colliculus of immobilized monkeys (Macaca mulatta and Macaca irus). Two main functional types of neurons were found. The neurons of the first type (Type I neurons) responded well to simple stationary and moving stimuli such as spots, bars or slits of light. The latency of their response was 41 ± 6 ms. They were not directionally selective and responded to a large range of velocities. The neurons of the second type (Type II neurons) responded very poorly to simple visual stimuli and their activation required real objects or certain two-dimensional patterns. The mean latency of response of these units was 66 ± 26 ms. Habituation was always present. Type II neurons were located in the lower part of the superficial layers. The characteristics of Type II neurons suggest that in the primate superior colliculus there is a mechanism that allows the recognition of the complexity and the novelty of a stimulus and guides orienting responses to those stimuli that are worth analyzing in detail.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 60 (1985), S. 151-158 
    ISSN: 1432-1106
    Keywords: Striate simple cells ; Static-field plots ; Receptive field subregions ; Moving light bar responses ; Hand and quantitative methods
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Cells in the simple family respond to a moving light bar with an average response histogram that is most commonly unimodal (single peak: encounter frequency, 64%) and less commonly bimodal (33%) or trimodal (3%). The mean width of the principal response peak given by hypercomplex I cells is narrower than that of simple cells and they have a lower mean optimal stimulus velocity. In a series of 74 cells (simple, 47; hypercomplex I, 27), detailed comparison of the spatial relations between the response peaks to the moving bar and the subregions to the stationary flashing bar led to the concept of a boundary response. The term “boundary response” refers to an isolated response peak occurring as a moving light bar leaves an OFF subregion that is the last in the sequence of subregions traversed by the bar. The presence of a boundary response leads to an apparent discrepancy between the number of response peaks to a moving light bar and the number of ON subregions in the static-field plot. The boundary response is necessarily completely direction selective. A detailed comparison of the properties of cells as revealed by hand and quantitative methods showed a very good agreement between the two methods in respect to the assignment of cells to the simple, B- and complex cell families. There were, however, serious discrepancies in respect to the receptive field organization of cells in the simple family. In particular, many cells that either failed to respond adequately to hand stimulation by a stationary flashing bar or exhibited only a single receptive field “subregion”, all responded with two or more subregions when examined quantitatively by the same kind of stationary stimulus.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 71 (1988), S. 475-490 
    ISSN: 1432-1106
    Keywords: Area 6 ; Macaque monkey ; Somatotopic map ; Proximal movements ; Visually responsive neurons
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Two series of experiments are reported in this paper. The first concerns the movement representation in the macaque inferior area 6, the second the functional properties of neurons located in the caudal part of this area (histochemical area F4). By combining single neuron recording and intracortical microstimulation, we found that inferior area 6 is somatotopically organized. The axio-proximal movements are represented caudally, the distal movements are represented near the arcuate sulcus. The mouth field is located laterally, the hand field medially. There is no leg field. A comparison between neuron properties and histochemical characteristics of inferior area 6 showed that the proximal movements representation includes most of area F4, whereas the distal movements representation corresponds to area F5 and to the rostral part of F4. Neurons located in that part of F4 where proximal movements are represented respond very well to tactile stimuli. They have large receptive fields mostly located on the face and on the upper part of the body. A large number of these neurons respond to visual stimuli. Objects approaching the animal are particularly effective. The tactile and the visual receptive fields are in register. The most represented movements are reaching movements, movements bringing the hand to the mouth or to the body and facial movements. There is a congruence between location of visual fields and preferred arm movements. It is argued that the receptive field arrangement and the response properties are more complex in area F4 than in the primary motor cortex and that area F4 neurons are involved in the control of arm movements towards different space sectors.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...