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  • 1
    Electronic Resource
    Electronic Resource
    Localized silicon etching using a laser-generated Cl source (1989)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 54 (1989), S. 561-563 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Ultraviolet laser photolysis of chlorine (λ=350–360 nm) has been used to produce a microscopic atomic chlorine source. Crystalline silicon has been etched and deep through-wafer vias have been fabricated. The etching process has been modeled as a combination of diffusion from the Cl source, and recombination and etching at the silicon surface. Both experimental and theoretical results are given.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.100931
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  • 2
    Electronic Resource
    Electronic Resource
    Distributed electron cyclotron resonance plasma immersion for large area ion implantation (invited) : Proceedings of the 7th international conference on ion sources (1998)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 69 (1998), S. 831-836 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Plasma-based ion implantation (PBII) is a recent method to implant ions into materials for modifying surface properties. Negative high voltage pulses are applied to the substrate to extract ions from the plasma and accelerate them directly onto the substrate surface. The main advantages of PBII over ion beam implantation are its simplicity for processing large surfaces or three-dimensional objects, and the possibility of preparing surfaces at low ion bombardment energy prior to the implantation process. However, in contrast to conventional ion implantation, the PBII process does not apply mass selection. Due to the wide ion sheath expansion (a few tens of cm), large volumes of plasma are mandatory around the substrate. Multipolar discharges, which produce a peripheral ionization facing the substrate and can be easily scaled up, are well adapted to the PBII process and thus widely used. However, hot filaments to sustain plasmas of reactive gases in multipolar magnetic field structures are progressively phased out in favor of distributed electron cyclotron resonance (DECR) plasma sources. The principle, the design, and the performances of DECR plasmas are presented. Then, PBII in DECR plasmas is illustrated through two selected examples.© 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1148530
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  • 3
    Electronic Resource
    Electronic Resource
    Simultaneous Spectrophotometric Determination of Cobalt and Nickel with 2,3-Quinoxalinedithiol. (1962)
    s.l. : American Chemical Society
    Analytical chemistry 34 (1962), S. 1378-1382 
    Details
    ISSN: 1520-6882
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ac60191a008
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  • 4
    Electronic Resource
    Electronic Resource
    Do ecto- and ericoid mycorrhizal fungi produce peroxidase activity? (1998)
    Springer
    Mycorrhiza 8 (1998), S. 61-65 
    Details
    ISSN: 1432-1890
    Keywords: Key words Lignin degradation ; Fenton reaction ; Hymenoscyphus ericae ; Lignin peroxidase ; Ectomycorrhizal fungi
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Several reports attest to the apparent ability of some ectomycorrhizal (ECM) and ericoid (ERM) mycorrhizal fungi to produce peroxidase enzyme activities during growth in axenic culture. In critically reviewing these data, we highlight that apparent peroxidase activities have been observed during growth in media containing 60–70 μM Fe. ECM and ERM fungi are known to produce H2O2 via carbohydrate oxidase activity and conditions in common culture media are favourable to the production of hydroxyl radicals, superoxide radicals and ferryl ions via the Fenton reaction. Free radicals so produced can mediate oxidation of substrates commonly used in presumptive peroxidase assays, leading to false-positive results. We argue that there is currently no evidence to support production of peroxidase activity by ECM or ERM fungi, but highlight circumstances in which peroxidase expression might be observed in future work.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s005720050213
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  • 5
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    Work and Family Precursors of Burnout in Teachers: Sex Differences (1988)
    New York, N.Y. : Periodicals Archive Online (PAO)
    Sex Roles. 18:3/4 (1988:Feb.) 215 
    Details
    ISSN: 0360-0025
    Topics: Archaeology
    URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pao:&rft_dat=xri:pao:article:v531-1988-018-03-000008
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  • 6
    Electronic Resource
    Electronic Resource
    Phasic modulation of short latency cutaneous excitation in flexor digitorum longus motoneurons during fictive locomotion (1988)
    Springer
    Experimental brain research 71 (1988), S. 568-578 
    Details
    ISSN: 1432-1106
    Keywords: Fictive locomotion ; Cutaneous reflex pathways ; Flexor digitorum longus muscle ; Motoneurons ; Interneurons ; Reflex modulation ; Spinal cord
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We examined modulation of transmission of short-latency excitation produced by distal hindlimb cutaneous input, as well as fluctuations in motoneuron membrane potential and input resistance, in flexor digitorum longus (FDL) motoneurons during fictive locomotion. Fictive stepping was induced in unaesthetized, decerebrate cats either by repetitive stimulation of the mesencephalic locomotor region (MLR) or by administration of Nialamide and 1 DOPA after low spinal section. In the MLR preparations, brief depolarizing waves occurred in FDL cells during the early flexion phase of fictive stepping, immediately after cessation of activity in extensor muscles. In some FDL cells, plateau-like depolarizations also occurred during the extensor phase. Fictive stepping induced in acutely spinalized cats by administration of l-DOPA was slower and more variable; peak polarization in FDL motoneurons always occurred during the early flexion phase but there was usually no distinct depolarization during extension. In both types of preparation, the initial EPSP components in synaptic potentials (SP-EPSPs) produced by electrical stimulation of the cutaneous division of the superficial peroneal nerve (SP) were maximally facilitated during early flexion, coincident with the peak of background depolarization. This enhancement was manifested by an increase in the amplitude of initial SP-EPSP components or by decreased central latency of the initial EPSP components, or both. In most FDL motoneurons, input resistance decreased systematically during late flexion, coincident with relative membrane hyperpolarization. Correction of SP-EPSP amplitudes for changes in input resistance suggested that SP-EPSP facilitation persisted throughout the flexion phase These findings are discussed with reference to modulation of cutaneous reflexes during locomotion and the possibility that excitatory last-order interneurons in particular cutaneous reflex pathways may distribute excitatory drive from the central pattern generator for locomotion to FDL α-motoneurons
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00248749
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  • 7
    Electronic Resource
    Electronic Resource
    Supraspinal control of a short-latency cutaneous pathway to hindlimb motoneurons (1988)
    Springer
    Experimental brain research 69 (1988), S. 449-459 
    Details
    ISSN: 1432-1106
    Keywords: Spinal cord ; Cutaneous reflex ; Red nucleus ; Pyramidal tract ; Spatial facilitation ; Excitatory interneurons ; Disynaptic pathway
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The effects of two supraspinal systems on transmission through a short latency hindlimb cutaneous reflex pathway were studied in cats anesthetized with pentobarbital or α-chloralose. Fleshman et al. (1984) described a mixed excitatoryinhibitory input from low threshold superficial peroneal (SP) afferents to flexor digitorum longus (FDL) motoneurons with central latencies so short as to suggest a disynaptic component in the initial excitatory phase of the PSP. In the present study, conditioning stimulation of either the red nucleus (RN) or the pyramidal tract (PT) caused a marked decrease in latency and increase in amplitude of both the excitatory and inhibitory components of the SP PSP in FDL motoneurons and several other motoneuron species. The minimal central latencies of the conditioned initial excitatory phase of the PSPs were on the order of 1.5 ms, consistent with the possibility of a disynaptic linkage. The facilitatory effects of RN and PT conditioning were observed in both anesthetic conditions, although preparation-specific differences in latency were observed. Lesion experiments suggested that the interneurons involved in this pathway are located caudal to the L5 segment, most likely in segments L6 and L7.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00247299
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  • 8
    Electronic Resource
    Electronic Resource
    Modulation of short latency cutaneous excitation in flexor and extensor motoneurons during fictive locomotion in the cat (1989)
    Springer
    Experimental brain research 77 (1989), S. 57-68 
    Details
    ISSN: 1432-1106
    Keywords: Cutaneous EPSPs ; Fictive locomotion ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We examined modulation of transmission in short-latency, distal hindlimb cutaneous reflex pathways during fictive locomotion in 19 decerebrate cats. Fictive stepping was produced either by electrical stimulation of the mesencephalic locomotor region (MLR) or by administration of Nialamide and 1-DOPA to acutely spinalized animals. Postsynaptic potentials (PSPs) produced by electrical stimulation of low threshold afferents (〈 2.5 times threshold) in the superficial peroneal (SP), sural, saphenous or medial plantar nerves were recorded intracellularly from various extensor (n = 28) and flexor (n = 24) motoneurons and averaged throughout the step cycle, together with voltage responses to intrasomatic constant current pulses (in order to monitor relative cell input resistance). Each motoneuron studied displayed rhythmic background oscillations in membrane potential and correlated variations in input resistance. The average input resistance of extensor motoneurons was lowest during mid-flexion, when the cells were relatively hyperpolarized and silent. Conversely, average input resistance of flexor motoneurons was highest during mid-flexion, when they were depolarized and active. The amplitude of the minimum-latency excitatory components of PSPs produced by cutaneous nerve stimulation were measured from computer averaged records representing six subdivisions of the fictive step cycle. Oligosynaptic EPSP components were consistently modulated only in the superficial peroneal responses in flexor motoneurons, which exhibited enhanced amplitude during the flexion phase. With the other skin nerves tested (sural, saphenous, and plantar), no consistent patterns of modulation were observed during fictive locomotion. We conclude that transmission through some, but not all, oligosynaptic excitatory cutaneous pathways is enhanced by premotoneuronal mechanisms during the flexion phase of fictive stepping in several cat hindlimb motor nuclei. The present results suggest that the patterns of interaction between the locomotor central pattern generator and excitatory cutaneous reflex pathways depend on the source of afferent input and on the identity of the target motoneuron population.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00250567
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  • 9
    Electronic Resource
    Electronic Resource
    The use of state-dependent modulation of spinal reflexes as a tool to investigate the organization of spinal interneurons (1999)
    Springer
    Experimental brain research 128 (1999), S. 263-277 
    Details
    ISSN: 1432-1106
    Keywords: Key words Spinal cord ; Motoneurons ; DOPA ; Locomotion ; Scratching ; Spatial facilitation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  This review examines the proposition that state-dependent modulation of transmission through spinal reflex pathways can be used as an investigative tool to reveal details about the organization of spinal interneurons into functional circuits. The first set of examples includes the use of spinal and supraspinal lesions, as well as the administration of the drug l-dihydroxyphenylalanine (l-DOPA), to produce different, relatively stable ”states” of the central nervous system (CNS), revealing previously unsuspected spinal pathways activated by the flexor reflex afferents (FRA). The second set of examples deals with the use of fictive locomotion and scratching to investigate the organization of oligosynaptic excitatory and inhibitory reflex pathways from cutaneous and muscle afferents. As in the first set of examples, several hitherto unknown reflex pathways have been found only during the flexion or extension phases of rhythmic locomotion, which are regarded as different CNS states. Differences in the patterns of control can be used to infer the existence of distinct sets of reflex pathway interneurons that have remarkably precise input/output relations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002210050847
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  • 10
    Electronic Resource
    Electronic Resource
    Disynaptic vestibulospinal and reticulospinal excitation in cat lumbosacral motoneurons: modulation during fictive locomotion (1996)
    Springer
    Experimental brain research 109 (1996), S. 277-288 
    Details
    ISSN: 1432-1106
    Keywords: Deiters' nucleus ; Medial longitudinal fasciculus ; Fictive locomotion ; Spinal cord ; Interneurons ; Decerebrate cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract This study compares some characteristics of the disynaptic excitatory pathways from the lateral vestibular nucleus (LVN) and medial longitudinal fasciculus (MLF) to lumbosacral α-motoneurons in the decerebrate cat. We used the spatial facilitation technique to test whether disynaptic LVN and MLF excitatory postsynaptic potentials (EPSPs) are produced by common last-order interneurons in the lumbosacral segments of the spinal cord. Of 77 motoneurons examined, 26 exhibited disynaptic EPSPs from both supraspinal sources. No spatial facilitation was found between LVN and MLF EPSPs in 21 of 24 cells that were adequately tested. In 3 of 23 cells (all flexor motoneurons), some spatial facilitation was found in some but not all trials. These observations suggest that stimulation of the LVN and MLF produces disynaptic EPSPs in motoneurons through largely separate populations of last-order interneurons. Disynaptic MLF and LVN EPSPs showed parallel patterns of modulation during fictive locomotion. Maximal disynaptic EPSP amplitudes occurred during the phase of the step cycle when the recorded motoneuron, whether flexor or extensor, exhibited depolarizing locomotor drive potentials and the corresponding muscle nerve was active. These observations, taken together, suggest that disynaptic LVN and MLF EPSPs are produced in motoneurons by at least four separate populations of segmental last-order excitatory interneurons, with separate populations projecting to flexor versus extensor cells. The results also suggest that the modulation of the disynaptic EPSPs during fictive locomotion is mainly due to premotoneuronal convergence of input from the respective descending systems and from the segmental central pattern generator for locomotion onto common interneurons.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00231787
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