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  • Polymer and Materials Science  (5)
  • Carbohydrate-rich diet  (2)
  • Cat  (2)
  • 1
    Electronic Resource
    Electronic Resource
    Fusimotor effects of midbrain stimulation on jaw muscle spindles of the anaesthetized cat (1993)
    Springer
    Experimental brain research 93 (1993), S. 37-45 
    Details
    ISSN: 1432-1106
    Keywords: Jaw muscle spindles ; Fusimotor control ; Midbrain ; Succinylcholine ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The effects of electrical stimulation within the midbrain on fusimotor output to the jaw elevator muscles were studied in anaesthetized cats. Muscle spindle afferents recorded in the mesencephalic trigeminal nucleus were categorised as primary or secondary by their responses to succinylcholine during sinusoidal or rampand-hold stretches. Changes in their stretch responses during midbrain stimulation were then assessed by changes in bias and in dynamic sensitivity. Problems were encountered in interpreting changes in sine wave stretch responses of primary afferents, in some of which a very small change in firing pattern produced large changes in estimates of the reponse amplitude. Sine wave testing also sometimes over-estimated static effects and under-estimated dynamic effects relative to ramp responses. On other occasions a small amount of static fusimotor activity caused a marked increase in sine response amplitude, which could be wrongly interpreted as a dynamic effect. Consequently, ramp responses only were used for diagnosing fusimotor changes. The most effective region for producing pure dynamic fusimotor excitation was directly rostral to the red nucleus, extending dorsally and ventrally approximately in the course of the retroflex bundle. Stimulation of regions caudal and dorso-caudal to the red nucleus, previously designated as the mesencephalic area for dynamic fusimotor control of leg muscles, gave static or mixed static and dynamic effects on jaw spindles. The use of midbrain stimulation to identify fusimotor neurones of jaw muscles as static or dynamic would be most reliable with stimulation just rostral to the red nucleus and would require spindle afferent behaviour to be monitored at the same time with ramp stretches.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00227778
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  • 2
    Electronic Resource
    Electronic Resource
    The responses of secondary endings of cat soleus muscle spindles to succinyl choline (1994)
    Springer
    Experimental brain research 100 (1994), S. 58-66 
    Details
    ISSN: 1432-1106
    Keywords: Muscle spindle ; Fusimotor Succinyl choline ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract This report describes the effects of succinylcholine (SCh) on the secondary endings of cat soleus muscle spindles and attempts to explain them in terms of the action of the drug on intrafusal fibres. All but 2 of 41 secondary endings studied in detail showed a significant response to a single intravenous injection of 200 μg kg-1 SCh. This consisted of a rise in the resting rate or development of a resting discharge if the spindle had previously been silent and an increase in the response to stretch. The increases in the responses to stretch were weaker than those observed for primary endings of spindles, but were much larger than those of tendon organs, which showed very little effect with this concentration of drug. The response to SCh showed two features consistent with its action being mediated via an intrafusal muscle fibre contraction rather than a direct depolarising action on the afferent nerve ending. In the presence of SCh, secondary endings were able to maintain a discharge during muscle shortening at rates, on average, more than 5 times greater than under control conditions. Secondly, the increase in spindle discharge produced by SCh showed a length dependence similar to that for fusimotor stimulation. Further support for the action of SCh being principally via an intrafusal fibre contraction was provided by the observation that its effects were abolished by the neuromuscular blocker gallamine triethiodide. The time course of recovery of SCh responses, following their blockade by gallamine, was much slower than recovery of extrafusal tension and closely paralleled that for the recovery of fusimotor responses. In three separate experiments on the medial gastrocnemius muscle the possibility that SCh may exert an excitatory action on spindle sensory endings through the liberation of potassium ions from the muscle was tested by tetanic stimulation of the muscle. This had no detectable excitatory effect. Several observations were made on the effect of SCh on responses of cutaneous receptors. SCh did not change levels of spontaneous activity or responses to mechanical stimulation of either slowly or rapidly adapting mechanoreceptors. It was argued for both tendon organs and cutaneous receptors that if SCh had a direct action on the nerve ending at the concentrations used here, some responses of these receptors to the drug might have been expected. All of the above supports the view that secondary endings of spindles are able to respond to SCh by the development of an intrafusal fibre contracture. The question of the intrafusal fibre types involved is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00227279
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  • 3
    Electronic Resource
    Electronic Resource
    Studies of lipase-catalyzed polyesterification of an unactivated diacid/diol system (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 2069-2079 
    Details
    ISSN: 0887-624X
    Keywords: Candida antarctica lipase ; Novozym 435® ; polyester ; enzymatic polymerization ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Preliminary enzymatic polymerization studies in the simple stoichiometric adipic acid/butane-1,4-diol system using lipase B from Candida antarctica, immobilized as Novozym 435®, suggest that in solvent-free conditions a step-growth mechanism operates involving the sequential addition of an AB synthon by esterification mode only. Conversely, in toluene as solvent there is a change to the more facile transesterification mode in line with the conventional polyesterification procedure, pointing to a change in specificity of the lipase. Evidence is drawn from qualitative studies using a series of synthetic intermediates, enabling authentication of product mixtures together with an indication of the comparative reactivity of species along the proposed reaction pathway. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 2069-2080, 1998
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    In situ studies of epitaxial silicon growth by gas source molecular beam epitaxy (1997)
    New York, NY [u.a.] : Wiley-Blackwell
    Advanced Materials for Optics and Electronics 7 (1997), S. 215-224 
    Details
    ISSN: 1057-9257
    Keywords: silicon ; epitaxy ; kinetics ; dynamics ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: The value of in situ monitoring to study growth dynamics and surface reaction kinetics in a gas source molecular beam epitaxy process is illustrated with reference to the growth of Si films on Si(001) substrates using a beam of disilane (Si2H6). By using a combination of reflection high-energy electron diffraction (RHEED) and reflection anisotropy spectroscopy (RAS), we show first how morphological (long-range order) and local electronic structure effects can be separated in the evaluation of growth dynamics. This involves the measurement of step density changes by RHEED concomitantly with the variation in domain coverage on the Si(001) (2×1)+(1×2) reconstructed surface by RAS. This approach is then extended to investigate the kinetics of hydrogen desorption, which is the rate-limiting step in Si growth from Si2H6. It is shown that over a significant temperature range, zeroth-order kinetics are obeyed and this is explained on the basis of a step-mediated desorption process. Finally we show how this influences the growth rate on substrates of differing degrees of vicinality. © 1997 John Wiley & Sons, Ltd.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    In-Situ mechanistic studies of the reaction of trimethylgallium and phosphine in zeolite H-Y (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Advanced Materials for Optics and Electronics 2 (1993), S. 313-318 
    Details
    ISSN: 1057-9257
    Keywords: MOCVD ; MAS-NMR ; CARS ; Quantum effects ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: Coherent anti-Stokes Raman scattering (CARS) has been utilised to monitor the decomposition of trimethylgallium (TMGa) on the reactive internal surface of the protonated form of zeolite Y under metal organic chemical vapour deposition (MOCVD) conditions designed to produce GaP deposits that exhibit quantum-size effects. The CARS data clearly reveal the facile room temperature decomposition of TMGa in the zeolite, as evidenced by the detection of increasing levels of methane with increasing reaction time. In addition, the zeolite samples were analysed by solid state nuclear magnetic resonance with magic angle spinning (MAS NMR) before reaction, after reaction of TMGa and after subsequent reaction with phosphine at 300°C. These data reveal that TMGa reacts with acid sites in the zeolite 12-rings, resulting in species containing methyl groups. Subsequent exposure to phosphine removes these methyl group protons, leaving various, as yet not fully characterised, phosphorus species. Exposure to phosphine does not appear to regenerate the acid sites on the zeolite.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/amo.860020606
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  • 6
    Electronic Resource
    Electronic Resource
    Simple and complex carbohydrate-rich diets and muscle glycogen content of marathon runners (1988)
    Springer
    European journal of applied physiology 57 (1988), S. 70-74 
    Details
    ISSN: 1439-6327
    Keywords: Energy metabolism ; Carbohydrate-rich diet ; Glycogen ; Low-carbohydrate diet
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The effects of simple-carbohydrate (CHO)- and complex-CHO-rich diets on skeletal muscle glycogen content were compared. Twenty male marathon runners were divided into four equal groups with reference to dietary consumption: depletion/simple, depletion/complex, non-depletion/simple, and nondepletion/complex. Subjects consumed either a low-CHO (15% energy [E] intake), or a mixed diet (50% CHO) for 3 days, immediately followed by a high-CHO diet (70% E intake) predominant in either simple-CHO or in complex-CHO (85% of total CHO intake) for another 3 days. Skeletal muscle biopsies and venous blood samples were obtained one day prior to the start of the low-CHO diet or mixed diet (PRE), and then again one day after the completion of the high-CHO diet (POST). The samples were analysed for skeletal muscle glycogen, serum free fatty acids (FFA), insulin, and lactate and blood glucose. Skeletal muscle glycogen content increased significantly (p〈0.05) only in the nondepletion/simple group. When groups were combined, according to the type of CHO ingested and/or utilization of a depletion diet, significant increases were observed in glycogen content. Serum FFA decreased significantly (p〈0.05) for the nondepletion/complex group only, while serum insulin, blood glucose, and serum lactate were not altered. It is concluded that significant increases in skeletal muscle glycogen content can be achieved with a diet high in simple-CHO or complex-CHO, with or without initial consumption of a low-CHO diet.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00691241
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  • 7
    Electronic Resource
    Electronic Resource
    Lipoprotein lipase activity in skeletal muscle and adipose tissue of marathon runners after simple and complex carbohydrate-rich diets (1988)
    Springer
    European journal of applied physiology 57 (1988), S. 75-80 
    Details
    ISSN: 1439-6327
    Keywords: Energy metabolism ; Carbohydrate-rich diet ; Lipoprotein lipase ; Free fatty acids ; Insulin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A comparison of the influence of simple and complex carbohydrate (CHO) consumption on adipose tissue- and skeletal muscle-lipoprotein lipase activity (AT-LPLA, SM-LPLA) was examined. Twenty male marathon runners were divided into two equal dietary groups: simple-CHO and complex-CHO. Half of the subjects in each group consumed either a low-CHO (15% energy [E] intake), or a mixed diet (50% CHO) for 3 days. Immediately following this dietary period, the subjects consumed a CHO-rich diet (70% E intake) predominant in simple-CHO or in complex-CHO for an additional 3 days. Thereafter, all subjects returned to a normal mixed diet. Skeletal muscle biopsies, adipose tissue aspirations, and venous blood samples were obtained prior to dietary manipulation (PRE), upon completion of the 6 day diet (POST I), and 2 weeks after returning to a normal diet (POST II). The samples were analysed for AT-LPLA, SM-LPLA, serum insulin, and free fatty acids (FFA), and blood glucose, and lactate. SM-LPLA fell 71% from PRE values of 0.39±0.30 μ mol · g−1 · h−1 to POST I values of 0.11 ±0.09 μ mol · g−1 · h−1 (means±SD) (p〈0.05), after a complex-CHO diet. However, the simple-CHO diet did not alter SM-LPLA. AT-LPLA similarly decreased (p〈0.05) after the complex-CHO diet, and no significant decrease was noted after the simple-CHO diet. Serum FFA decreased significantly (p〈0.05) after a simple-CHO diet (0.82±0.13 to 0.65±0.10 mmol l−1) but were unchanged after a complex-CHO diet. Blood glucose and lactate, and serum insulin were not altered following a CHO-rich diet.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00691242
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  • 8
    Electronic Resource
    Electronic Resource
    Role of chemical surface heterogeneity in the adhesion of photocured resins to ceramic substratesPaper presented at ECASIA 93, Cataria, Sicily, 4-8 October 1993. (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Surface and Interface Analysis 21 (1994), S. 697-702 
    Details
    ISSN: 0142-2421
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: The surface composition of various ceramic substrates used for electronics applications is heterogeneous. In the case of debased alumina, this may result from the diffusion of sintering aids such as silica, added during the manufacturing process, which produce a complex bonding surface. In this study, the durability of a visible light curing resin applied to a variety of ceramic substrates of differing acidity/basicity was investigated. Butt-joints consisting of photocured resin adhered to quartz, silicon wafers and polished alumina were produced. Following immersion in water at 50°C for periods of several weeks, joints were fractured (in situ in the VG ESCALAB Mk II and just prior to loading into the Scienta ESCA300). Angle-resolved XPS analysis was carried out on both sides of the failure. Failure occurred cohesively, with 1-2 nm of polymer remaining on the ceramic side of the failure. Orientation of the oxygenated functional groups of the polymer was observed within this overlayer, with methoxy groups being aggregated immediately adjacent to the inorganic surface; subtle differences were observed between the polished alumina and other substrates. An absence of the aromatic groups from the photocured polymer was also noted on the ceramic side of the failure. These results are explained in terms of acid-base interactions, and a model for adhesion and subsequent failure of the system is proposed.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/sia.740211004
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  • 9
    Electronic Resource
    Electronic Resource
    Influence of formulation chemistry on the locus of failure of adhesive joints (1995)
    Chichester [u.a.] : Wiley-Blackwell
    Surface and Interface Analysis 23 (1995), S. 342-348 
    Details
    ISSN: 0142-2421
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: The durability of photocured resins adhered to ceramic substrates has been investigated. Monochromated XPS and time-of-flight SIMS were employed to determine the precise locus of failure in butt-joints comprised of a photocured resin adhered to either a 96% pure, debased alumina substrate or single-crystal silicon. Prolonged (〉 14 days) immersion in water at 50°C resulted in cohesive failure, with 1-2 nm of polymer remaining on one of the ceramic substrates. An absence in the spectrum of any components attributable to characteristic groups from a major constituent of the polymer within this overlayer suggested the possibility that one of the minor resin components was aggregating at the organic/inorganic interface to produce an in situ weak boundary layer. The interactions of some of the organic molecules present in the formulation with the α-alumina substrate were investigated using molecular modelling techniques to indicate the most favourable interactions with the substrate. Durability studies were also carried out on a reformulated photocured resin to investigate the effect of removal of the ethoxylated methacrylate monomer, suspected of being the principal organic component at the weak boundary layer, on both joint performance and locus of failure.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/sia.740230511
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