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Showing papers by "University of Leeds published in 1990"


Journal ArticleDOI
TL;DR: Ce rapport de synthese tente de fournir une vue generale sur les relations possibles qui existent entre les effets du Ca 2+ a l'interieur des mitochondries and le besoin d'ATP reclame par les cellules des vertebres.
Abstract: Ce rapport de synthese tente de fournir une vue generale sur les relations possibles qui existent entre les effets du Ca 2+ a l'interieur des mitochondries et le besoin d'ATP reclame par les cellules des vertebres

1,344 citations


Journal ArticleDOI
TL;DR: Proteins that Change the Properties of the Extracellular Matrix, Extensins: hydroxyproline-rich glycoproteins .
Abstract: 1. 1 ntrodllction . . 2. Activation of Defense Responses . . 3. Classes of Defense-Related Proteins ... . . . . ....... .. ... . . . . . . . . . . . . . .. . . ... .... . . . . . . .. . . . Core enzymes of phenylpropanoid metabolism ........ " .. . . . . . . "" . . . . . . . . . . . . . . . . . . . 4. Proteins that Change the Properties of the Extracellular Matrix , Extensins: hydroxyproline-rich glycoproteins . Glycine-rich proteins . Peroxidases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Cinnamyl alcohol dehydrogenase .... .. . . . .... .. . . ........ . ...... .. . . . .... . ....... . . . . . .. . Callose synthetase . 5. Proteins Associated with Deterrence and Antimicrobial Activif)l . . Endohydrolases ........ .. ......... ...... . "'" Thionins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ������a;!: li fn�r:;;���;��. : : : : : : : : : : : : : : : : : : : :: : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : Late enzymes of phytoalexin biosynthesis . 6. Additional Defense-Related Proteins " . . . . . . . . . . Pathogenesis-related proteins ........ " . .. . . . . . . . . . . . . . . . . ..... . . . . . . . . . . . . . . . .. Proteins encoded by wun 1 and wun 2 . . Proteins encoded by win 1 and win 2 . ELl products . . . ... .... . . . . . .. . . . . . . . . . . . . . . . . ... . . . . . . . . . . . . . . . . . ... . . . . . . . . . . . . . . . .. . . . .. . . . . Elicitor-induced products . . . . . .. . . . . . . . . . . . . . . . . . . . .. . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7. Coordination of Defense Responses """""""" . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . , 8. Concluding Remarks... .. . .. .. . . . ...... ".

1,073 citations


Journal ArticleDOI
TL;DR: The final amount of force developed by heart muscle during acidosis is the complex sum of these changes, possibly by a direct action on the cross bridges.
Abstract: It has been known for over 100 years that acidosis decreases the contractility of cardiac muscle. However, the mechanisms underlying this decrease are complicated because acidosis affects every step in the excitation-contraction coupling pathway, including both the delivery of Ca2+ to the myofilaments and the response of the myofilaments to Ca2+. Acidosis has diverse effects on Ca2+ delivery. Actions that may diminish Ca2+ delivery include 1) inhibition of the Ca2+ current, 2) reduction of Ca2+ release from the sarcoplasmic reticulum, and 3) shortening of the action potential, when such shortening occurs. Conversely, Ca2+ delivery may be increased by the prolongation of the action potential that is sometimes observed and by the rise of diastolic Ca2+ that occurs during acidosis. This rise, which will increase the uptake and subsequent release of Ca2+ by the sarcoplasmic reticulum, may be due to 1) stimulation of Na+ entry via Na(+)-Ca2+ exchange; 2) direct inhibition of Na(+)-Ca2+ exchange; 3) mitochondrial release of Ca2+; and 4) displacement of Ca2+ from cytoplasmic buffer sites by H+. Acidosis inhibits myofibrillar responsiveness to Ca2+ by decreasing the sensitivity of the contractile proteins to Ca2+, probably by decreasing the binding of Ca2+ to troponin C, and by decreasing maximum force, possibly by a direct action on the cross bridges. Thus the final amount of force developed by heart muscle during acidosis is the complex sum of these changes.

660 citations


Journal ArticleDOI
TL;DR: This review deals with the mechanism and the methods used to follow lipid oxidation, as well as the interaction of lipids/lipid oy~idation products with food components and their possible biological effects.

464 citations


Journal ArticleDOI
TL;DR: Between 1979 and 1981, 45,130 women in Edinburgh aged 45-64 were entered into a randomised trial of breast cancer screening by mammography and clinical examination, which showed a mortality reduction of 17% in women aged 50 years and over.

433 citations


Journal ArticleDOI
TL;DR: Animals use springs in all three ways but there seems to be a need for more use of springs in legged robots, especially in robots designed to run fast.
Abstract: Running animals and robots can save energy and reduce unwanted heat production by bouncing along on springs, using the principle of the pogo stick. (The principal springs in animals are tendons.) They can make further energy savings by using return springs to halt the legs at the end of each foward or backward swing and start them swinging the other way. The forces at impact of feet with the ground can be moderated by compliant foot pads, which can improve road holding by preventing "chatter" (vibrations in which the foot repeatedly leaves and returns to the ground before settling). Animals use springs in all three ways but there seems to be a need for more use of springs in legged robots, especially in robots designed to run fast.

430 citations


Journal ArticleDOI
TL;DR: The deduced sequence of the 488‐amino‐acid protein (MsrA) revealed the presence of two ATP‐binding motifs homologous to those of a family of transport‐related proteins from Gram‐negative bacteria and eukaryotic cells, including the P‐glycoprotein responsible for multidrug resistance.
Abstract: Summary A Staphylococcus epidermidis plasmid conferring inducible resistance to 14-membered ring macrolides and type B streptogramins has been analysed and the DNA sequence of the gene responsible for resistance determined. A single open reading frame of 1.464kbp, preceded by a complex control region containing a promoter and two ribosomal binding sites, was identified. The deduced sequence of the 488-amino-acid protein (MsrA) revealed the presence of two ATP-binding motifs homologous to those of a family of transport-related proteins from Gram-negative bacteria and eukaryotic cells, including the P-glycoprotein responsible for multidrug resistance. In MsrA, but not these other proteins, the two potential ATP-binding domains are separated by a Q-linker of exceptional length. Q-linkers comprise a class of flexible inter-domain fusion junctions that are typically rich in glutamine and other hydrophilic amino acids and have a characteristic spacing of hydrophobic amino acids, as found in the MsrA sequence. Unlike the other transport-related proteins, which act in concert with one or more hydrophobic membrane proteins, MsrA appears to function independently when cloned in a heterologous host (Staphylococcus aureus RN4220). MsrA might, therefore, interact with and confer antibiotic specificity upon other transmembrane efflux complexes of staphylococcal cells. The active efflux of [14C]-erythromycin from cells of S. aureus RN4220 containing msrA has been demonstrated.

366 citations


Journal ArticleDOI
TL;DR: Analysis of a broad spectrum of defensive behaviors is being used to develop test batteries providing simplified models of these phenomena, with results indicating that the latter can be predicted with a high degree of accuracy.

340 citations


Journal ArticleDOI
01 Dec 1990-Fuel
TL;DR: In this article, pyrolysis temperatures up to 720 °C and at heating rates between 5 and 80 °C min−1 were used to determine the composition and properties of the derived gases and oils.

331 citations


Journal ArticleDOI
01 Feb 1990-Gut
TL;DR: A significant increase in the proportion of attached bacteria in cases showing histological epithelial degeneration, and a significant decrease in cases show intraepithelial polymorph infiltration are found.
Abstract: Ultrastructural examination of biopsies showing Helicobacter pylori associated chronic gastritis reveals close attachment between gastric surface epithelial cells and the organism. The finding of 'adhesion pedestals', which represents a cellular response to the presence of the organism, is analogous to the response of intestinal cells to enteropathogenic E coli. Thus the development of bacterial attachment sites in H pylori associated gastritis might be an indication of pathogenicity. We have therefore explored the relationship between the proportion of organisms forming attachment sites and histological indices of disease 'activity'. Antral biopsies from 40 patients with H pylori positive gastritis were examined histologically and ultrastructurally, and the percentage of attached organisms compared with subjective assessments of epithelial degeneration, mucin depletion, polymorphonuclear and chronic inflammatory cell infiltration. We found a significant increase in the proportion of attached bacteria in cases showing histological epithelial degeneration, and a significant decrease in cases showing intraepithelial polymorph infiltration. The direct relationship between bacterial attachment and cellular degeneration lends further support to a pathogenic effect. Reduced attachment in the face of polymorph infiltration might indirectly reflect aspects of the immune response--namely, blocking of adhesion by IgA, with complement activation and generation of leucotactic factors.

293 citations


Journal ArticleDOI
TL;DR: Several DNA extraction techniques were quantitatively and qualitatively compared using both fresh and paraffin wax embedded tissue and their suitability investigated for providing DNA and RNA for the polymerase chain reaction (PCR).
Abstract: Several DNA extraction techniques were quantitatively and qualitatively compared using both fresh and paraffin wax embedded tissue and their suitability investigated for providing DNA and RNA for the polymerase chain reaction (PCR). A one hour incubation with proteinase K was the most efficient DNA extraction procedure for fresh tissue. For paraffin wax embedded tissue a five day incubation with proteinase K was required to produce good yields of DNA. Incubation with sodium dodecyl sulphate produced very poor yields, while boiling produced 20% as much DNA as long enzyme digestion. DNA extracted by these methods was suitable for the PCR amplification of a single copy gene. Proteinase K digestion also produced considerable amounts of RNA which has previously been shown to be suitable for PCR analysis. A delay before fixation had no effect on the amount of DNA obtained while fixation in Carnoy's reagent results in a much better preservation of DNA than formalin fixation, allowing greater yields to be extracted.

Journal ArticleDOI
TL;DR: Topographically distinct, but often overlapping, systems of neurons and fibres displaying immunoreactivity (ir) related to a range of neuropeptides were found in most brain areas.
Abstract: The comparative distribution of peptidergic neural systems in the brain of the euryhaline, viviparous teleost Poecilia latipinna (green molly) was examined by immunohistochemistry. Topographically distinct, but often overlapping, systems of neurons and fibres displaying immunoreactivity (ir) related to a range of neuropeptides were found in most brain areas. Neurosecretory and hypophysiotrophic hormones were localized to specific groups of neurons mostly within the preoptic and tuberal hypothalamus, giving fibre projections to the neurohypophysis, ventral telencephalon, thalamus, and brain stem. Separate vasotocin (AVT)-ir and isotocin (IST)-ir cells were located in the nucleus preopticus (nPO), but many AVT-ir nPO neurons also displayed growth hormone-releasing factor (GRF)-like-ir, and in some animals corticotrophin-releasing factor (CRF)-like-ir. The main group of CRF-ir neurons was located in the nucleus recessus anterioris, where coexistence with galanin (GAL) was observed in some cells. Enkephalin (ENK)-like-ir was occasionally present in a few IST-ir cells of the nPO and was also found in small neurons in the posterior tuberal hypothalamus and in a cluster of large cells in the dorsal midbrain tegmentum. Thyrotrophin-releasing hormone (TRH)-ir cells were found near the rostromedial tip of the nucleus recessus lateralis. Gonadotrophin-releasing hormone (GnRH)-ir cells were present in the nucleus olfactoretinalis, ventral telencephalon, preoptic area, and dorsal midbrain tegmentum. Molluscan cardioexcitatory peptide (FMRF-amide)-ir was colocalized with GnRH-ir in the ganglion cells and central projections of the nervus terminalis. Melanin-concentrating hormone (MCH)-ir neurons were restricted to the tuberal hypothalamus, mostly within the nucleus lateralis tuberis pars lateralis, and somatostatin (SRIF)-ir neurons were numerous throughout the periventricular areas of the diencephalon. A further group of SRIF-ir neurons extending from the ventral telencephalon into the dorsal telencephalon pars centralis also contained neuropeptide Y (NPY)-, peptide YY (PYY)-, and NPY flanking peptide (PSW)-like-ir. These immunoreactivities were, however, also observed in non-SRIF-ir cells and fibres, particularly in the mesencephalon. Calcitonin gene-related peptide (CGRP)-like-ir had a characteristic distribution in cells grouped in the isthmal region and fibre tracts running forward into the hypothalamus, most strikingly into the inferior lobes. Antisera to cholecystokinin (CCK) and neurokinin A (NK) or substance P (SP) stained very extensive, separate systems throughout the brain, with cells most consistently seen in the ventral telencephalon and periventricular hypothalamus. Broadly similar, but much more restricted, distributions of cells and fibres were seen with antisera to neurotensin (NT) and vasoactive intestinal peptide (VIP).(ABSTRACT TRUNCATED AT 400 WORDS)

Journal ArticleDOI
01 Jun 1990-Pain
TL;DR: It is concluded that further research on memory for pain should be informed by reference to methodological practices developed in cognitive psychology and embedded within an appropriate theoretical framework.
Abstract: This paper reports a qualitative review of the literature on memory for pain. Most research has focused on the accuracy of memory for pain intensity. There is some evidence that recall is moderately accurate but this conclusion is tentative because of significant methodological problems. There is also some evidence that recall of acute pain is more accurate than recall of chronic pain and we make some suggestions as to why this difference might occur. We conclude that further research on memory for pain should be informed by reference to methodological practices developed in cognitive psychology and embedded within an appropriate theoretical framework.

Journal ArticleDOI
TL;DR: A hierarchy of relaxations obtained by combining enumeration of initial sequences with Smith's rule can be formulated as a linear programming problem in an enlarged space of variables and new valid inequalities for the problem are obtained.

Journal ArticleDOI
TL;DR: The continuum model for small epsilon is used to reanalyse the instability of a uniform suspension and it is demonstrated that the only significant contribution to sigma is that derived from the stresslets associated with the cells' intrinsic swimming motions.
Abstract: A new continuum model is formulated for dilute suspensions of swimming micro-organisms with asymmetric mass distributions. Account is taken of randomness in a cell's swimming direction, p, by postulating that the probability density function for p satisfies a Fokker-Planck equation analogous to that obtained for colloid suspensions in the presence of rotational Brownian motion. The deterministic torques on a cell, viscous and gravitational, are balanced by diffusion, represented by an isotropic rotary diffusivity Dr, which is unknown a priori, but presumably reflects stochastic influences on the cell's internal workings. When the Fokker-Planck equation is solved, macroscopic quantities such as the average cell velocity Vc, the particle diffusivity tensor D and the effective stress tensor sigma can be computed; Vc and D are required in the cell conservation equation, and sigma in the momentum equation. The Fokker-Planck equation contains two dimensionless parameters, lambda and epsilon; lambda is the ratio of the rotary diffusion time Dr-1 to the torque relaxation time B (balancing gravitational and viscous torques), while epsilon is a scale for the local vorticity or strain rate made dimensionless with B. In this paper we solve the Fokker-Planck equation exactly for epsilon = 0 (lambda arbitrary) and also obtain the first-order solution for small epsilon. Using experimental data on Vc and D obtained with the swimming alga, Chlamydomonas nivalis, in the absence of bulk flow, the epsilon = 0 results can be used to estimate the value of lambda for that species (lambda approximately 2.2; Dr approximately 0.13 s-1). The continuum model for small epsilon is then used to reanalyse the instability of a uniform suspension, previously investigated by Pedley, Hill & Kessler (1988). The only qualitatively different result is that there no longer seem to be circumstances in which disturbances with a non-zero vertical wavenumber are more unstable than purely horizontal disturbances. On the way, it is demonstrated that the only significant contribution to sigma, other than the basic Newtonian stress, is that derived from the stresslets associated with the cells' intrinsic swimming motions.

Journal ArticleDOI
TL;DR: By varying the boundary conditions and a parameter in the partial differential equation, it is demonstrated that a wide variety of surface shapes are accessible to the method.
Abstract: A method of generating free-form surfaces using solutions to a suitably chosen partial differential equation is discussed. By varying the boundary conditions and a parameter in the partial differential equation, it is demonstrated that a wide variety of surface shapes are accessible to the method.

Journal ArticleDOI
TL;DR: The majority of nursing home residents have psychiatric disorders on admission, and that their management is often quite restrictive, demonstrating that the best methods of treatment for nursing home patients with mental disorders are now needed.
Abstract: The prevalence of psychiatric disorders among new admissions to nursing homes is unknown. Such data are needed to estimate the psychiatric needs of this population. We report the prevalence of specific psychiatric disorders in 454 consecutive new nursing home admissions who were evaluated by psychiatrists and diagnosed according to the Diagnostic and Statistical Manual of Mental Disorders, third edition, revised. Eighty percent had a psychiatric disorder. The commonest were dementia syndromes (67.4%) and affective disorders (10%). Also, 40% of demented patients had additional psychiatric syndromes such as delusions or depression, and these patients constituted a distinct subgroup that predicted frequent use of restraints and neuroleptics, and the greatest consumption of nursing time. These data demonstrate that the majority of nursing home residents have psychiatric disorders on admission, and that their management is often quite restrictive. Research is now needed to determine the best methods of treatment for nursing home patients with mental disorders.

Journal ArticleDOI
TL;DR: Perfusion in situ of the placenta of intact or previously parathyroidectomized fetal lambs has been used to assess the ability of three mid‐molecule fragments of the humanParathyroid hormone‐related protein (PTHrP) molecule to stimulate the placental transport of calcium and magnesium.
Abstract: Perfusion in situ of the placenta of intact or previously parathyroidectomized fetal lambs has been used to assess the ability of three mid-molecule fragments of the human parathyroid hormone-related protein (PTHrP) molecule to stimulate the placental transport of calcium and magnesium. PTHrP(67-86 amide) was most effective but some activity was also shown by PTHrP(75-86 amide) and by PTHrP (75-84) in decreasing order. This placental action of PTHrP(67-86 amide) was rapid and could be observed using the placenta from an intact fetus, whereas it was necessary to use the placenta from a previously parathyroidectomized fetus to demonstrate stimulation of placental calcium transport by PTHrP(1-84). PTHrP(67-86 amide) may resemble the molecule that activates the placental calcium pump.

Journal ArticleDOI
TL;DR: Cytokines are peptides used by immune and inflammatory cells to communicate with each other and to control the milieu interieur in which they operate and the availability of recombinant DNA techniques to produce cytokines in almost unlimited quantities is leading to new and exciting therapeutic applications.
Abstract: Cytokines are peptides used by immune and inflammatory cells to communicate with each other and to control the milieu interieur in which they operate. Recent evidence suggests that they are of immense importance in controlling the local and systemic events of the immune response, inflammation, hemopoiesis, healing, and the systemic response to injury. Many of them can now be measured by immunoassay, and the role of such measurements in the diagnosis and management of disease is actively under investigation. Similarly, the availability of recombinant DNA techniques to produce cytokines in almost unlimited quantities is leading to new and exciting therapeutic applications.

Journal ArticleDOI
TL;DR: An idealized model for the analysis of the results of extraction in a flow system by a supercritical fluid from a matrix which contains small quantities of extractable materials, such that the extraction is not limited by solubility is suggested in this paper.
Abstract: An idealized model is suggested for the analysis of the results of extraction in a flow system by a supercritical fluid from a matrix which contains small quantities of extractable materials, such that the extraction is not limited by solubility. The model is that of diffusion out of a homogeneous spherical particle into a medium in which the extracted species is infinitely dilute. The effect of matrix shape and size variation and also solubility limitations on the model, which occur in real systems, are discussed. Predictions of the model are compared with experimental results for systems which are mostly physically unlike the ideal model. However, important features of the behavior of these systems are found to accord with the predictions of the model. The use of the model gives an insight useful for the design of industrial extraction processes and also provides an extrapolation method for obtaining quantitative analytical extraction results relatively quickly.

Journal ArticleDOI
TL;DR: It is proposed that state transitions in cyanobacteria are triggered by changes in the redox state of plastoquinone or a closely associated electron carrier.
Abstract: The mechanism by which state 1-state 2 transitions in the cyanobacterium Synechococcus 6301 are controlled was investigated by examining the effects of a variety of chemical and illumination treatments which modify the redox state of the plastoquinone pool. The extent to which these treatments modify excitation energy distribution was determined by 77K fluorescence emission spectroscopy. It was found that treatment which lead to the oxidation of the plastoquinone pool induce a shift towards state 1 whereas treatments which lead to the reduction of the plastoquinone pool induce a shift towards state 2. We therefore propose that state transitions in cyanobacteria are triggered by changes in the redox state of plastoquinone or a closely associated electron carrier. Alternative proposals have included control by the extent of cyclic electron transport around PS I and control by localised electrochemical gradients around PS I and PS II. Neither of these proposals is consistent with the results reported here.

Journal ArticleDOI
TL;DR: The modular nature of the integration process greatly facilitates the frequent updating of OWL following releases of the source databases, and the extent of redundancy in these sources is revealed by the comparison process.
Abstract: A strategy has been developed for the construction of a validated, comprehensive composite protein sequence database. Entries are amalgamated from primary source data bases by a largely automated set of processes in which redundant and trivially different entries are eliminated. A modular approach has been adopted to allow scientific judgement to be used at each stage of database processing and amalgamation. Source databases are assigned a priority depending on the quality of sequence validation and commenting. Rejection of entries from the lower priority database, in each pairwise comparison of databases, is carried out according to optionally defined redundancy criteria based on sequence segment mismatches. Efficient algorithms for this methodology are embodied in the COMPO software system. COMPO has been applied for over 2 years in construction and regular updating of the OWL composite protein sequence database from the source databases NBRF-PIR, SWISS-PROT, a GenBank translation retrieved from the feature tables, NBRF-NEW, NEWAT86, PSD-KYOTO and the sequences contained in the Brookhaven protein structure databank. OWL is part of the ISIS integrated data resource of protein sequence and structure [Akrigg et al. (1988) Nature, 335, 745-746]. The modular nature of the integration process greatly facilitates the frequent updating of OWL following releases of the source databases. The extent of redundancy in these sources is revealed by the comparison process. The advantages of a robust composite database for sequence similarity searching and information retrieval are discussed.

Journal ArticleDOI
TL;DR: Results correlated with the inhibition of P-450DM in broken cell preparations, confirming that all five azoles are potent inhibitors of ergosterol biosynthesis in C. albicans.
Abstract: The interaction of azole antifungal antibiotics with purified Candida albicans cytochrome P-450-dependent 14 alpha-sterol demethylase (P-450DM) was measured spectrophotometrically and by inhibition of enzyme activity. Ketoconazole and ICI 153066 (a triazole derivative) formed low-spin complexes with the ferric cytochrome and induced type II difference spectra. These spectra are indicative of an interaction between the azole moiety and the sixth co-ordination position of P-450DM haem. Both azoles inhibited the binding of CO to the sodium dithionite-reduced ferrous cytochrome, and inhibited reconstituted P-450DM activity by binding to the cytochrome with a one-to-one stoichiometry. Similarly, total inhibition of enzyme activity occurred when equimolar amounts of clotrimazole, miconazole or fluconazole were added to reconstituted P-450DM. These results correlated with the inhibition of P-450DM in broken cell preparations, confirming that all five azoles are potent inhibitors of ergosterol biosynthesis in C. albicans.

Journal ArticleDOI
TL;DR: A simple model, which takes into account the mechanical properties of muscle, predicts optimum take-off techniques that agree well with those used by athletes and are remarkably insensitive to the numerical values assigned to the physiological parameters.
Abstract: High jumpers run at moderate speeds and set down the foot, from which they take off, well in front of the body. Long jumpers run up much faster and place the foot less far forward, with the leg at a steeper angle. A simple model, which takes into account the mechanical properties of muscle, predicts optimum take-off techniques that agree well with those used by athletes. These predictions are remarkably insensitive to the numerical values assigned to the physiological parameters.

Journal ArticleDOI
TL;DR: In this article, a series of interviews with audit managers focusing on the planning of audit work was conducted to explore the differing functions that audit activities can serve, such as a techno-rational function designed to enhance audit quality, the activity of audit planning also serves both significant ideological and marketing functions, and the latter designed to maintain and if possible increase the fee income from the client.

Book
01 Jan 1990
TL;DR: The basic data in chapter 2 were the evaluation functions Ψ j and the constraints w ∈ S and the estimate ω of w, and the current best alternative will be called a * and its evaluation Ψ*(ω).
Abstract: The basic data in chapter 2 were the evaluation functions Ψ j and the constraints w ∈ S. In addition, we now have an estimate ω of w. We rank the alternatives according to Ψ j (ω). The current best alternative will be called a * and its evaluation Ψ*(ω). However, we must be ready to criticise that ranking: sensitivity analysis comes to the fore.

Journal ArticleDOI
TL;DR: The authors concluded that the segmental analgesia produced by intrathecally midazolam is mediated by the benzodiazepine-GABA receptor complex that is involved in other benzODiazepine actions.
Abstract: The electrical current thresholds for pain (ECTP) in the skin of the neck and tail were measured in rats with chronically implanted lumbar subarachnoid catheters The effects of a benzodiazepine antagonist and a gamma-aminobutyric acid (GABA) antagonist on the analgesic effects of equivalent doses of midazolam, fentanyl, and ketocyclazocine were studied These were the minimum doses producing maximal segmental analgesia when given intrathecally (ie, they all caused a significant and maximum increase in ECTP in the tail, which was similar for all three drugs, but no significant change in the ECTP in the neck) Flumazenil (Ro 15-1788) administration caused a parallel shift to the right of the dose-response curve for midazolam spinal analgesia Segmental analgesia following midazolam was also significantly attenuated (P less than 005) when the selective GABA antagonist bicuculline was given intrathecally at the same time as midazolam The highest dose of bicuculline used (50 pmol) caused no significant attenuation of the segmental analgesic effects of either ketocyclazocine or fentanyl The authors concluded that the segmental analgesia produced by intrathecal midazolam is mediated by the benzodiazepine-GABA receptor complex that is involved in other benzodiazepine actions

Journal ArticleDOI
TL;DR: Intact, electrically excitable fibre bundles were isolated from the fast and slow myotomal muscle of the bullrout and pre-stretch of active muscle provides an important mechanism for storing potential energy for release during the shortening part of the cycle.
Abstract: Intact, electrically excitable fibre bundles were isolated from the fast and slow myotomal muscle of the bullrout ( Myoxocephalus scorpius L.). Power output was measured under conditions simulating their activity in a fish swimming at different speeds. Preparations were subjected to sinusoidal length changes of ±5% of resting length, and stimulated briefly during each cycle. The number and timing of stimuli were adjusted at each cycle frequency to maximise power output. Maximum power was produced at 5–7 Hz for fast fibres (25–35 W kg−1) and 2 Hz for slow fibres (5–8 Wkg−1). Under these conditions, pre-stretch of active muscle provides an important mechanism for storing potential energy for release during the shortening part of the cycle.

Journal ArticleDOI
TL;DR: In this paper, an anxiety/defense test battery was designed to assess defensive reactions of laboratory rats to situations associated with nonpainful threat (exposure to a cat), and the battery measured three defense patterns, movement inhibition, risk assessment behaviors, and inhibition of non-defensive behaviors, in two tasks.
Abstract: An anxiety/defense test battery was designed to assess defensive reactions of laboratory rats to situations associated with nonpainful threat (exposure to a cat). The battery measured three defense patterns, movement inhibition, risk assessment behaviors, and inhibition of nondefensive behaviors, in two tasks. Diazepam (4.0 mg/kg) altered four of five risk assessment measures, but failed to show an anxiolytic effect on movement inhibition, and had minimal and inconsistent effects on inhibition of nondefensive behaviors. The risk assessment changes with diazepam were all consistent with an anxiolytic action of diazepam. These results provide a partial contrast to the general lack of anxiolytic action of diazepam in a fear/defense test battery designed to measure reactions to a discrete, present, threat stimulus, and suggest a greater diazepam effect on risk assessment than on other aspects of defensive responding. Sex differences indicating higher defensiveness for female than male rats were obtained on many of these measures.

Journal ArticleDOI
TL;DR: In this paper, a new theoretical framework is presented for understanding the dielectric response of relaxor ferroelectrics, based on the lead magnesium niobate, a well-known relaxor material, and the existence of a ferroelectric network linking niobium-oxygen coordination octahedra.