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  • 1995-1999  (9)
  • 1980-1984  (7)
  • 1
    Electronic Resource
    Electronic Resource
    Subpicosecond pulse generation in synchronously pumped and hybrid ring dye lasers (1981)
    Springer
    Applied physics 26 (1981), S. 179-183 
    Details
    ISSN: 1432-0649
    Keywords: 42.55 Mv ; 42.60 Da
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Subpicosecond pulse generation has been examined in synchronously pumped mode-locked ring dye laser systems. These include hybrid and composite absorber/gain media arrangements as well as a simple synchronous cavity. The shortest pulses recorded were 0.3 ps for the hybrid system, and this has been shown to be critically dependent on the positioning of the absorber jet in the centre of the cavity to better than 50 μm. Stable operation for subpicosecond pulse generation has been achieved in the ring configuration with greater wavelength tunability and higher average power conversion efficiency than with conventional cavity arrangements.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00692444
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  • 2
    Electronic Resource
    Electronic Resource
    SuperDARN studies of the ionospheric convection response to a northward turning of the interplanetary magnetic field (1998)
    Springer
    Annales geophysicae 16 (1998), S. 549-565 
    Details
    ISSN: 0992-7689
    Keywords: Ionosphere (Auroral ionosphere) ; Magnetospheric physics (Magnetopause, cusp, and boundary layers; Magnetosphere-ionosphere interaction)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract The response of the dayside ionospheric flow to a sharp change in the direction of the interplanetary magnetic field (IMF) measured by the WIND spacecraft from negative Bz and positive By, to positive Bz and small By, has been studied using SuperDARN radar, DMSP satellite, and ground magnetometer data. In response to the IMF change, the flow underwent a transition from a distorted twin-cell flow involving antisunward flow over the polar cap, to a multi-cell flow involving a region of sunward flow at high latitudes near noon. The radar data have been studied at the highest time resolution available (∼2 min) to determine how this transition took place. It is found that the dayside flow responded promptly to the change in the IMF, with changes in radar and magnetic data starting within a few minutes of the estimated time at which the effects could first have reached the dayside ionosphere. The data also indicate that sunward flows appeared promptly at the start of the flow change (within ∼2 min), localised initially in a small region near noon at the equatorward edge of the radar backscatter band. Subsequently the region occupied by these flows expanded rapidly east-west and poleward, over intervals of ∼7 and ∼14 min respectively, to cover a region at least 2 h wide in local time and 5° in latitude, before rapid evolution ceased in the noon sector. In the lower latitude dusk sector the evolution extended for a further ∼6 min before quasi-steady conditions again prevailed within the field-of-view. Overall, these observations are shown to be in close conformity with expectations based on prior theoretical discussion, except for the very prompt appearance of sunward flows after the onset of the flow change.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s00585-998-0549-0
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  • 3
    Electronic Resource
    Electronic Resource
    Variations in the polar cap area during intervals of substorm activity on 20–21 March 1990 deduced from AMIE convection patterns (1996)
    Springer
    Annales geophysicae 14 (1996), S. 879-887 
    Details
    ISSN: 0992-7689
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract The dynamic behaviour of the northern polar cap area is studied employing Northern Hemisphere electric potential patterns derived by the Assimilative Mapping of Ionospheric Electrodynamics (AMIE) procedure. The rate of change in area of the polar cap, which can be defined as the region of magnetospheric field lines open to the interplanetary magnetic field (IMF), has been calculated during two intervals when the IMF had an approximately constant southward component (1100- 2200 UT, 20 March 1990 and 1300–2100 UT, 21 March 1990). The estimates of the polar cap area are based on the approximation of the polar cap boundary by the flow reversal boundary. The change in the polar cap area is then compared to the predicted expansion rate based on a simple application of Faraday’s Law. Furthermore, timings of magnetospheric substorms are also related to changes in the polar cap area. Once the convection electric field reconfigures following a southward turning of the IMF, the growth rate of the observed polar cap boundary is consistent with that predicted by Faraday’s Law. A delay of typically 20 min to 50 min is observed between a substorm expansion phase onset and a reduction in the polar cap area. Such a delay is consistent with a synthesis between the near Earth neutral line and current disruption models of magnetospheric substorms in which the dipolarisation in the magnetotail may act as a trigger for reconnection. These delays may represent a propagation time between near geosynchronous orbit dipolarisation and subsequent reconnection further down tail. We estimate, from these delays, that the neutral X line occurs between \sim35RE and \sim75RE downstream in the tail.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s00585-996-0879-8
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  • 4
    Electronic Resource
    Electronic Resource
    The response of the magnetosphere to the passage of a coronal mass ejection on March 20–21 1990 (1997)
    Springer
    Annales geophysicae 15 (1997), S. 671-684 
    Details
    ISSN: 0992-7689
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract The geomagnetic response to the passage of a coronal mass ejection (CME) is studied. The passage of the CME resulted in a storm sudden commencement (SSC) at 2243 UT on March 20 1990 with disturbed magnetic activity during the following 24 h. The auroral, sub-auroral and equatorial magnetic response to the southward turning at 1314 (±5) UT on March 21 and the equatorial response to the southward turning associated with the SSC on 20 March are discussed in terms of existing models. It is found that the auroral and sub-auroral response to the southward turning associated with the SSC is a factor 2 or more quicker than normal due to the shock in the solar wind dynamic pressure. The low-latitude response time to the south-ward turning, characterised by Dst and the magneto-pause current corrected Dst*, is una.ected by the shock. Dst and Dst*, characteristic of the equatorial magnetic field, responded to the 1314 (±5) UT southward turning prior to the first observed substorm expansion phase onset, suggesting that a dayside loading process was responsible for the initial enhancement in the ring current rather than nightside particle injection. The response time of the auroral and sub-auroral magnetic field to the southward turning at 1314 (±5) UT on March 21 is measured at a variety of longitudes and latitudes. The azimuthal propagation velocity of the response to the southward turning varied considerably with latitude, ranging from #x0223C;8 km s−1 at 67°N to ∼4 kms−1 at 55°N. The southward velocity of the equatorward boundary of the northern polar convection pattern has been measured. This velocity was ∼1.2 km s−1 at 1600 MLT, although there was evidence that this may vary at different local times.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s00585-997-0671-4
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  • 5
    Electronic Resource
    Electronic Resource
    UVB therapy decreases the adhesive interaction between peripheral blood mononuclear cells and dermal microvascular endothelium, and regulates the differential expression of CD54, VCAM-1, and E-selectin in psoriatic plaques (1996)
    Oxford, UK : Blackwell Publishing Ltd
    British journal of dermatology 134 (1996), S. 0 
    Details
    ISSN: 1365-2133
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Summary A dermal lymphocytic infiltrate is a characteristic feature of psoriasis, and may be involved in the pathogenesis of the disease. We have previously shown that specialized dermal microvascular endothelial cells (DMEC) in psoriatic lesions promote the selective adherence of the CD4 CD45Ro helper T-cell subset. In this study, we examined the adhesive interaction between peripheral blood mononuclear cells and psoriatic DMEC in patients treated with ultraviolet B light (UVB), and correlated the results with the expression and function of endothelial adhesion molecules on DMEC. Seven psoriatic patients were exposed to one MED of UVB daily for 14 days, and the binding properties of their peripheral blood mononuclear cells (PBMC), and tissue specimens taken from their lesions on days 0, 2, 3, 6, 8, 11 and 14 of UVB treatment, were studied. The ability of psoriatic PBMC to adhere to non-irradiated control or UVB-treated psoriatic plaques was reduced by 70% after treatment with 2–3 MED, and complete inhibition was obtained after 8–11 MED. In contrast, exposure of psoriatic plaques to 2–3 MED had no effect on the capacity of DMEC to support normal PBMC binding, which was only reduced after 8–11 MED. In addition, psoriatic plaques which were shielded from direct UVB exposure also showed decreased PBMC binding, suggesting a systemic effect of UVB treatment. Immunoperoxidase staining revealed that CD54 (ICAM-1) and E-selectin were strongly expressed on dermal vessels in untreated psoriatic plaques. Treatment of patients with 6–8 MED significantly decreased CD54 and E-selectin, but was markedly induced following UVB treatment. In functional blocking studies, preincubation of tissue from untreated psoriatic plaques with anti-E-selectin antibody, but not antibodies against CD54 and VCAM-1, significantly inhibited the ability to bind normal PBMC. These observations suggest that UVB treatment interferes with the adhesive properties of both psoriatic PBMC and endothelial cells, and differentially regulates the expression of endothelial adhesion molecules. The study also provided direct evidence for the involvement of E-selectin in the adhesion of circulating lymphocytes to psoriatic endothelial cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2133.1996.d01-750.x
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  • 6
    Electronic Resource
    Electronic Resource
    Control of epidermal cell proliferation in vitro (1984)
    Oxford, UK : Blackwell Publishing Ltd
    British journal of dermatology 111 (1984), S. 0 
    Details
    ISSN: 1365-2133
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Epidermis from explants of keratome slices of domestic pig skin can be induced to migrate, proliferate, and stratify if at least two serum protein factors and a source of nucleosides are present.The factor which is necessary for cell movement or spreading is destroyed by heating the serum to 100 C and is resistant to 80° C heating. This factor has a molecular weight of 65,000 and is identical to the ‘epibolin’ found by Stenn.Proliferation is dependent on a serum factor which is destroyed by heating to 80° C. However, cells which are denied this factor can make their own proliferation factors(s). Cell migration and cell proliferation usually occur together but they can be dissociated and are therefore independent phenomena.Increased cell proliferation can be achieved by some retinoids at the proper concentration but steroids, epidermal growth factor, a phorbol ester (TPA), and the use of injured skin as a keratome source failed to show in vitro hyperproliferation. Mitotic inhibition, however, can be induced by a variety of metabolic poisons (methotrexate, 5-fluorouracil, hydroxyurea), steroids, retinoids at high concentrations, and agents which increase adenosine 3′,5′-nionophosphate (cAMP).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2133.1984.tb15578.x
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  • 7
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    Psychosocial Effects on Parents of Raising a Physically Handicapped Child (1981)
    New York : Periodicals Archive Online (PAO)
    Journal of Abnormal Child Psychology. 9:1 (1981:Mar.) 121 
    Details
    ISSN: 0091-0627
    Topics: Psychology
    URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pao:&rft_dat=xri:pao:article:h225-1981-009-01-000009
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  • 8
    Electronic Resource
    Electronic Resource
    Impulsivity resulting from frontostriatal dysfunction in drug abuse: implications for the control of behavior by reward-related stimuli (1999)
    Springer
    Psychopharmacology 146 (1999), S. 373-390 
    Details
    ISSN: 1432-2072
    Keywords: Key words Compulsion ; Addiction ; Cocaine ; Amphetamine ; Cannabis ; Phencyclidine ; Nucleus accumbens ; Amygdala ; Frontal cortex ; Limbic ; Stimulus-reward association ; Conditioned reward ; Sensitization ; Drug-seeking ; Inhibitory control ; Cognition ; Conditioned stimulus ; Incentive motivational ; Dopamine ; Rat ; Monkey
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Drug abuse and dependence define behavioral states involving increased allocation of behavior towards drug seeking and taking at the expense of more appropriate behavioral patterns. As such, addiction can be viewed as increased control of behavior by the desired drug (due to its unconditioned, rewarding properties). It is also clear that drug-associated (conditioned) stimuli acquire heightened abilities to control behaviors. These phenomena have been linked with dopamine function within the ventral striatum and amygdala and have been described specifically in terms of motivational and incentive learning processes. New data are emerging that suggest that regions of the frontal cortex involved in inhibitory response control are directly affected by long-term exposure to drugs of abuse. The result of chronic drug use may be frontal cortical cognitive dysfunction, resulting in an inability to inhibit inappropriate unconditioned or conditioned responses elicited by drugs, by related stimuli or by internal drive states. Drug-seeking behavior may thus be due to two related phenomena: (1) augmented incentive motivational qualities of the drug and associated stimuli (due to limbic/amygdalar dysfunction) and (2) impaired inhibitory control (due to frontal cortical dysfunction). In this review, we consider the neuro-anatomical and neurochemical substrates subserving inhibitory control and motivational processes in the rodent and primate brain and their putative impact on drug seeking. The evidence for cognitive impulsivity in drug abuse associated with dysfunction of the frontostriatal system will be discussed, and an integrative hypothesis for compulsive reward-seeking in drug abuse will be presented.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00005483
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  • 9
    Electronic Resource
    Electronic Resource
    Enhanced responding for conditioned reward produced by intra-accumbens amphetamine is potentiated after cocaine sensitization (1999)
    Springer
    Psychopharmacology 142 (1999), S. 31-40 
    Details
    ISSN: 1432-2072
    Keywords: Key words Locomotor activity ; Nucleus accumbens ; d-Amphetamine ; Cocaine ; Sensitization ; Conditioned reward
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The mesolimbic dopamine (DA) system has been implicated in conditioned reward (CR), locomotor sensitization, and the reinforcing properties of psychomotor stimulants. Stimuli with formerly motivationally neutral properties that gain incentive properties by their predictive association with primary reinforcers are termed conditioned, or secondary, reinforcers. In these experiments, we investigated whether cocaine sensitization could potentiate augmented responding for CR produced by intra-accumbens amphetamine. After subjects were trained on the CR paradigm for 14 days, they received a regimen of cocaine sensitization or saline injections. On 2 test days, 8–10 days later, subjects were given amphetamine (6 µg/0.5 µl) or saline infusions into the nucleus accumbens (NAc) and responding for CR was measured using the ”acquisition of a new response” paradigm. Responding on one novel lever resulted in the delivery of the conditioned stimulus (conditioned reinforcer, or CR lever), whereas responding on the other lever resulted in no CR stimulus presentation (NCR lever). Animals sensitized to cocaine showed increased responding on the CR lever after intra-NAc saline and potentiated CR lever responding after intra-NAc amphetamine. No differences in responding between the cocaine- and saline-treated groups on the NCR lever after the challenge were found. Locomotor sensitization under these conditions was confirmed in a separate group of subjects. These findings show that prior exposures to cocaine results in changes that potentiate the ability of intra-NAc amphetamine to enhance CR. Repeated stimulant drug use may induce long-term neuronal adaptations that result in increased sensitivity to the behavioral, or incentive motivational, effects of stimulant drugs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002130050859
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  • 10
    Electronic Resource
    Electronic Resource
    Investigation of viscosity dependent fluorescence lifetime using a synchronously operated picosecond streak camera (1980)
    Springer
    Applied physics 21 (1980), S. 13-17 
    Details
    ISSN: 1432-0630
    Keywords: 33.50 ; 06.60 ; 82.50
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Exciting with picosecond pulses from a mode locked cw dye laser and using the Synchroscan continuously operating streak camera, the variation in the fluorescence lifetime with viscosity over the range 0.5 cp–250 cp of some mode locking and potential mode locking polymethine dyes of the cyanine family were investigated. The measured lifetimes were found to follow a ∼2/3 or 1/3 power dependence of the viscosity η.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00886477
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