bluuebunny/crossref_metadata_2025 huggingface dataset:
Gastric mechanisms in CCK satiety
Authors: Moran Timothy H , McHugh Paul R
Published: November 2023

A role for the brain-gut peptide CCK in the control of food intake was originally proposed in 1973 by Gibbs et al. (1973a). Since that time, a range of experiments has been carried out detailing the actions of CCK on food intake, examining the mechanisms by which it may exert these effects, and addressing the potential relationship of the actions of exogenously administered CCK to a physiological role for the endogenously released peptide. In this chapter, we shall attempt to place CCK into an integrative chain of physiological events produced by the entrance of ingested food into the gastrointestinal tract and resulting in the termination of food intake. We shall review our own experimental results and those from other laboratories and evaluate the hypothesis that at least part of the inhibition of food intake produced by exogenous CCK results from mimicking the actions of the endogenous peptide in the inhibition of gastric emptying.
Selective CCK receptor antagonists and macronutrient consumption in the rat
Authors: Francis John , Cooper Steven J
Published: November 2023

It has been shown that the selective CCKA receptor antagonist devazepide reliably blocked the reduction in food intake produced by exogenously administered CCK-8 (Dourish et al. 1989a). Reidleberger and O’Rourke (1989) demonstrated that devazepide administered alone increased food intake in rats deprived of food for 1 h. Dourish et al. (1989b) have shown that not only devazepide but also the selective CCKB receptor antagonist L-365,260 increased food intake in satiated rats. The increases in food intake in these experiments were modest, and rats had to be deprived of food for only a short period of time or presatiated before the effects of the antagonists could be observed.Liddle et al. (1986) showed that neither carbohydrates nor fats, high percentage components of test meals, caused significant CCK release in rats. Only ingestion of a protein meal (casein) caused significant increases in plasma CCK concentration. Therefore it would seem that ingestion of a protein-rich diet would cause optimum CCK release during feeding. If CCK release is dependent on macronutrients (protein in the rat), then it follows that the effects of selective CCK antagonists on food intake may in turn be dependent on the nutrient composition of the diet. In general it would be expected, on this argument, that increases in intake produced by antagonists should be more closely related to protein ingestion than to either fat or carbohydrate ingestion (but see also Chapter 18 of this volume).
A study of the ‘coexpression’ of CCK and tyrosine hydroxylase messenger RNAs in the rat substantia nigra
Authors: Kiyama H , McGowan E , Emson P C
Published: November 2023

Developments in the technique of in situ hybridization using enzyme-labelled or biotin-labelled DNA probes have enabled us to utilize a combination of isotopic and non-isotopic in situ procedures to demonstrate the presence of two messenger RNAs (mRNAs) in one cell, i.e. ‘coexpression’ studies (Kiyama and Emson 1990). The study of ‘coexpression’ is a logical development of many of the earlier studies of coexistence, where double-labelling techniques using antibodies visualized two or more immunoreactivities in a single cell (H6kfelt et al. 1980a). The problem with methods used to demonstrate coexistence was that they depended on the use of antibodies which recognized, to variable extents, epitopes related to the desired antigen. Thus in studies of coexistence possible cross-reactivity of the antibodies used may confound the study and the application of drugs such as colchicine is often required to increase the neuronal content of the antigen. As colchicine itself can induce changes in neuropeptide gene expression, the use of this drug in neuroanatomical studies needs to be carefully controlled (Kiyama and Emson 1991) as it may result in false positives in coexpression studies.It was because of these potential problems with present coexistence studies that we developed a technique that enabled us to use two oligonucleotide probes (one radio-labelled and the other non-isotopically labelled) to visualize two mRNAs in a single neuron.
CCK and movement disorders
Authors: Boyce Susan , Rupniak Nadia M j.
Published: November 2023

Basal ganglia diseases seriously compromise an individual’s ability to perform activities of daily living, and many limitations are associated with current treatments. Movement disorders range from akinetic/hypokinetic syndromes such as Parkinson’s disease, where movement is extremely impoverished, to hyperkinetic conditions involving excessive and uncontrollable movements as in Huntington’s chorea and drug-induced dyskinesias. The profound effect of dopamine receptor agonists and antagonists on movement clearly implicate abnormalities of dopamine function in aberrant motor control. The clinical similarity between drug-induced and spontaneous movement disorders further suggests a common pathophysiology. The close association of CCK with dopamine in the mesolimbic and basal ganglia structures suggests that it may also be involved in the regulation of motor activity. In this chapter we shall discuss the functional interactions of CCK and dopamine, the potential use of CCK agonists and antagonists in the treatment of movement disorders, and the possible problems associated with such therapies.
CCK and opioid interactions in the spinal cord
Authors: Dickenson Anthony H , ullivan Ann F , Magnuson David S
Published: November 2023

CCK is present in widespread areas of the CNS including the spinal cord, where it is found in high levels, and released from those areas of the dorsal horn involved in the transmission and modulation of sensory messages. (Yaksh et al. 1982; Yaksh and Noueihed 1985; Williams et al. 1987). There is evidence that CCK not only produces neuronal excitation in the dorsal born (Jeftinija et al. 1981; Dickenson and Magnuson 1989) but can also act to reduce the antinociception produced by morphine and yet produce analgesia in other circumstances (Baber et al. 1989). The ability of CCK to interfere with morphine analgesia may be relevant to the clinical states where morphine responsiveness is reduced (Arner and Meyerson 1988). We have used recordings of nociceptive neurons in the rat spinal cord to gauge the effects of a variety of opioid receptor agonists on the transmission of peripheral sensory responses in the anaesthetized animal (Dickenson et al. 1987). Clear but independent inhibitions of the noxious evoked activities of these cells follows the activation of µ and o opioid receptors (Dickenson et al. 1987; Sullivan et al. 1989). Here we have studied the ability of CCK to interfere with µ and o opioid actions in the spinal cord and by the use of antagonists attempted to identify the CCK receptor subtypes involved. The recording of sensory neurons allows the actions of these agents to be studied without the complication of sedative, motor, or motivational effects influencing the findings.
Overview of epidemiological findings, physiological effects, and proposed mechanisms of biological interaction with low-level electric and magnetic fields
Authors: Hamnerius Yngve
Published: November 2023

Intense electric and magnetic fields have long been known to cause biological effects. The mechanisms are well known, e.g. heat production or triggering of nerve cells. However, research results from the past decade give evidence in numerous experiments that there are also biological effects of low-level electric and magnetic fields. The evidence for effects comes from both epidemiological and experimental studies.
Resonant ion-transport phenomena: possible mechanisms
Authors: Durney Carl H
Published: November 2023

Recent reports in the literature suggest that biological responses to combined d.c. and a.c. magnetic fields occur within narrow ranges of both frequency and a.c. magnetic field strengths, i.e. within frequency and amplitude ‘windows’. Furthermore, this resonance response seems to be related to the cyclotron ·frequency of the bare (unsolvated) ion. Since most familiar mechanisms would show an increased response with increased field strength, the observation of an amplitude window suggests a possible unfamiliar mechanism related to the presence of combined d.c. and a.c. magnetic fields. Blackman et al. (1985) found that certain combinations of a.c. magnetic field strength, d.c. magnetic field strength, and frequency changed calcium efflux in chick-brain preparations. Thomas et al. (1986) found that combined d.c.-a.c. magnetic fields strongly affected rats’ abilities to press levers within a narrow time window after receiving a stimulus. Smith et al. (1987) showed that combined d.c. and a.c. magnetic fields caused a strong resonance response with frequency in the motility of diatoms placed on the surface of an agar substrate impregnated with calcium. The prominent characteristics of these observations seem to be:
Electromagnetic field-induced permeability of the blood-brain barrier shown by immunohistochemical methods
Authors: Salford Leif G , Brun Arne , Eberhardt Jacob , Malmgren, Lars , Persson Bertil R R
Published: November 2023

The mammal brain is protected from potentially harmful compounds in the blood by the so-called blood-brain barrier (BBB)- a selectively permeable, hydrophobic barrier which is readily crossed by small, lipid-soluble molecules, (Rapoport 1976; Oldendorf 1977). Certain lipid-insoluble molecules such as glucose also readily cross the cell layers constituting the barrier via carrier proteins that have a high affinity to specific molecules.
European Exobasidiales and their galls
Authors: Ing Bruce
Published: November 2023

Exobasidiales are obligate parasites on leaves and shoots of Ericaceae, Lauraceae, Saxifragaceae, and Theaceae. They are heterobasidiomycetous fungi with no vegetative structures of their own, utilizing the somatic tissues of their hosts to support either systemic or annual mycelia and spore producing organs. The European genera are reviewed including observations on morphology, host species, and distribution. The extent of gall formation varies, from thickened, discoloured leaf spots in Arcticomyces and some Exobasidium species, through well-developed leaf pouch galls caused by Exobasidium to the clavarioid stem galls of Laurobasidium. A key to European species, based on host damage, is provided.
The communities associated with the galls of Andricus quercuscalicis (Hymenoptera: Cynipidae) an invading species in Britain: a geographical view
Authors: Schonrogge K , Stone G N , Cockrellt B , Crawley M j.
Published: November 2023

The agamic knopper gall of Andricus quercuscalicis in Britain provides an opportunity to investigate the guild associated with a cynipid gall in the process of its development. Species reared in association with the knopper gall include inquilines, which develop in the gall without having direct contact to the gall-causing lava, and parasitoids, both of the gall wasp and of the inquilines. Most of the members of the guild associated with A. quercuscalicis are polyphagous and bi- or multivoltine (that is, they attack more than one gall and have two or more generations per year) and, therefore, need alternative hosts, constituting ecological links between A. quercuscalicis and the local cynipid community in general. An extensive rearing programme of galls collected in Britain and on the European continent was carried out to examine qualitative and quantitative variations on different spatial scales.
Structure-activity studies of natural products with anti-inflammatory/ immunomodulatory effects
Authors: Borlin L
Published: November 2023

Pharmacognosy, in contrast to medicinal chemistry, can start from an observed activity of a drug used in man or animals. Subsequent bioassay-directed fractionation can then lead to the discovery of previously unknown chemical structures for further structure-activity studies. In the search for ‘new’ substances which influence the immune system, many possible biological targets are available.
Search for noncariogenic sweeteners from medicinal plants
Authors: Kinghorn A D , Suttisri R , Lee I S
Published: November 2023

Naturally occurring carbohydrate or caloric sweeteners such as sucrose are still the most widely used sweetening agents. Sucrose is paramount among sweet compounds in that it produces sweetness that is unmasked by any other taste sensation. However, quite large quantities of sucrose are necessary to sweeten foods, beverages, and medicines, and it is now accepted that sucrose is the main dietary source of dental caries in developed and developing countries alike. In addition, the abundant usage of carbohydrate sweeteners can result in other deleterious consequences such as high caloric intake and nutritional imbalance. Therefore, much effort has been expended towards the discovery of additional examples of highly sweet, non-nutritive, organic molecules that do not promote dental caries, especially for use in diabetic and dietetic products.
The chemistry and bioactivities of some natural products from Chinese herbs
Authors: Zhou B N
Published: November 2023

The abundant resources of medicinal plants in China and the rich empirical knowledge of Chinese folk medicine, which has accumulated over several millenia, encouraged us to embark on chemical and pharmacological studies of Chinese traditional medicine. The aim of our laboratory is the investigation of herbs with proven clinical efficacy. Over recent years, we have successfully isolated several lead compounds and some new natural products from Chinese traditional medicines. In this chapter, the chemistry of pseudolaric acid (an antifungal agent), yuanhuacin (a specific protein kinase C phorbol ester receptor antagonist), huperzine A (a compound used for treatment of senile dementia), and sarmentosin (a serum glutamate pyruvate transaminase (SGPT) lowering agent for hepatitis patients) is reviewed. Chemical and pharmacological studies were completed in our institute, and the compounds mentioned have been recommended in China for clinical trials.
The role of PEPC phosphorylation in theregulation of C4 photosynthesis
Authors: Gadal P , Pacquit V , Giglioll N , Bui V -L , Piere J N , Echevarria C , Vidal J
Published: November 2023

Leaves of C plants are characterized by concentrically organized photosynthetic tissues, i.e. an outer mesophyll (M) surrounding inner bundle sheath (BS) cells in which two metabolic cycles, the C and Calvin cycles, are working in concert to achieve CO assimilation. In ‘L-malate formers’, the primary fixation of CO (in its hydrated form) is carried out by the enzyme phosphoenolpyruvate carboxylase (E.C. 4.1.1.31, PEPC) in the cytoplasm ofM-cells to form oxaloacetic acid (OAA) which will be reduced to L-malate in the M chloroplasts; diffusive transport of Lmalate to BS-cells and its decarboxylation by NADP-malic enzyme in the chloroplast stroma make CO available for incorporation by ribulose bisphosphate carboxylase/oxygenase (Rubisco) in the Calvin cycle (Fig. 4.1) (Hatch 1987).
Protein phosphorylation and circadian rhythms
Authors: Nimmo H G , Carter P J , Fewson C A , Nimmo G A , Wiljins M B
Published: November 2023

Phosphoenolpyruvate carboxylase (PEPc) (EC 4.1.1.31) catalyses the fixation of CO (as HCO-) into oxaloacetate. It plays an anaplerotic role in nonphotosynthetic tissues and in the leaves of C plants. In the leaves of C plants it is located in the mesophyll tissue and catalyses the first committed step in the C pathway of CO assimilation (see, for example, Andreo et al. 1987). In this article, however, we concentrate on the regulation of PEPc in plants that perform Crassulacean acid metabolism (CAM). In CAM, PEPc is responsible for the nocturnal fixation of atmospheric CO; the oxaloacetate produced is reduced to malate which is stored as malic acid in the vacuole. During the following light period, the malate is released from the vacuole and decarboxylated, and the resulting CO is fixed in the Calvin cycle (Osmond and Holtum 1981). Consideration of the metabolic pathways involved in CAM suggests that mechanisms must exist to permit flux through PEPc at night and reduce or eliminate it during the day. In this article we describe the role of phosphorylation in the regulation of PEPc in leaves of the CAM plant Bryophyllum (Kalanchoii) fedtschenkoi.
The control of light-coupled leaf metabolism by reversible protein phosphorylation
Authors: Mackintosh C , Douglas P , Douglas F , Lillo C , Moorhead G
Published: November 2023

In green leaves, the primary products of photosynthetic electron transport in the chloroplast, namely ATP, NADPH, and reduced ferredoxin (Fdrect), are fed into many assimilatory and reductive pathways that are collectively known as ‘lightcoupled’ pathways (Anderson and Beardall 1991). Light-coupled pathways in the chloroplast include assimilation of CO into triose-P, reassimilation of photorespired NH, the assimilation of NO-into glutamate, and synthesis of many amino acids. In addition, light-generated ATP, NADPH, and/or Fd,ect support the export of reducing equivalents and phosphorylated compounds from the chloroplast to supply light-enhanced processes, such as sucrose biosynthesis and reduction of NO-, in the cytosol.
The role of phosphorylation in the regulation of phenylalanine ammonia-lyase
Authors: Bolwell G P , Davies D R , Gerrish C
Published: November 2023

One level of control of metabolic processes is mediated by the reversible phosphorylation of target proteins by protein kinases and phosphatases. These mechanisms are universal to all biological systems but only relatively recently has the extent of the involvement of such mechanisms in regulatory processes begun to be appreciated in plant systems. A number of protein kinases and protein phosphatases have now been characterized at the gene and protein levels in plants and some of their targets identified. The work described here concerns a key step in phenolic metabolism and phosphorylation events that might be involved in overall regulation of the phenylpropanoid pathway.
Molecular cloning of differentially expressed and cell cycle-related cDNAs in the maize root apex
Authors: Sabellil P A
Published: November 2023

Recent work on lower (yeast) and higher eukaryotic cells (animals and plants) has resulted in a consensus picture of the molecular factors which control the cell cycle. It is clear that the master cell cycle regulators are highly conserved across species and the progression of the cell cycle is regulated by very similar sets of molecules in all eukaryotic cells. It is also widely recognized that protein phosphorylation is central to cell cycle regulation in eukaryotes. However, different organisms are not only characterized by obviously different developmental patterns and lifestyles, but are also likely to have developed specific mechanisms for the spatial and temporal control of cell division. Here we briefly describe some of the more remarkable features of cell proliferation in higher plants as opposed to the cell cycle in yeast and animals. We also describe the root apex of maize which represents our experimental system to identify both evolutionary conserved genes encoding key cell cycle regulators and novel plant genes which may play important roles in the coordination of cell cycle events in relation to the organization of the meristem and plant development.
Expression of CDK gene variants and p34cdc-related protein kinase activities in synchronized alfalfa cells
Authors: Magyar Z , Meszaros T , Feher A , Brown S , Deak M , Bottka S , Gyorgyey J , Pongor S , Dudits D
Published: November 2023

The central role of p34cctc2-related kinases in control of cell cycle progression has been shown in a great variety of eukaryotic cells. In yeasts the cdc2/CDC28 genes encode the p34 serine/threonine protein kinase required for S phase and entry into mitosis. The p34cctcltcocs catalytic subunit requires association with a cyclin regulatory subunit for kinase activity. The cyclin-dependent protein kinases (CDKs) are complexed with different cyclins and extensively regulated by phosphorylation (reviewed by Solomon 1993). In multicellular eukaryotes different cyclins bind different CDKs during progression through various phases of the cell cycle (Pines 1993). The phylogenetic conservation of the p34cctc kinase function has allowed the identification of several plant homologues of the cdc2/CDC28 genes and the complementation of yeast mutation by plant cdc2 cDNAs (Hirayama et al. 1991; Hirt et al. 1991; Ferreira et al. 1991; Colasanti et al. 1991). Sequence analysis and functional characterization of various cdc2 gene variants revealed differences between plant cdc2 genes (Miao et al. 1993; Hirt et al. 1993). Differential expression of cdc2 genes was also detected after hormone treatment and in various tissues and organs of plants (Hirt et al. 1991; Martinez et al. 1992; Magyar et al. 1993; Fobert et al. 1994).
Introduction
Authors: Tomás-Barberán Francisco A , Robins Richard J
Published: November 2023

Secondary metabolites play a number of crucial roles in fruit and vegetables, being responsible for colour, appearance, flavour and taste. Thus, it is primarily the content of these metabolites within the product that is also responsible both for consumer selection of the commodity and for the enjoyment derived from its consumption. While it has long been recognized that ‘fruit and vegetables are good for you’, studies of fruit and vegetables over the last few years have demonstrated that these products contain constituents—notably vitamins and fibre—essential to a healthy, well-balanced diet. Furthermore, it has also been shown that some of the secondary metabolites of fruit and vegetables are beneficial to health in directly combating the onset of cancer and coronary diseases.
The emergence of stratigraphy
Authors: Hallam A
Published: November 2023

Generations of British and American geologists have been indoctrinated as students with the view that the English canal surveyor William Smith (1769-1839) was the father of stratigraphy. This has never been accepted, with good reason, on the European continent, where stratigraphy has been perceived as emerging gradually from a long tradition dating well back into the eighteenth century, with the seminal influence deriving from Werner.
The Ice Age
Authors: Hallam A
Published: November 2023

What are nowadays universally seen as deposits directly or indirectly due to glacial activity provided in the early part of the nineteenth century some of the strongest evidence in support of the diluvialist school of thought. Vast tracts of land in Northern Europe and around the Alps had long been known to be mantled by a chaotic assemblage of sediments ranging from muds, silts, sands, and gravels, which frequently had contorted structures, to extremely poorly sorted deposits we now refer to as till, with pebbles and boulders of rock embedded in a fine-grained matrix.
The age of the earth
Authors: Hallam A
Published: November 2023

It is customary for us nowadays to chuckle at Archbishop Ussher’s famous calculation that the earth was created in 4004 BC on 26 October at 9.00 a.m! Such an attitude fails to do justice to the highly scholarly tradition of textual and historical criticism within which Ussher worked, as a figure much respected by his contemporaries.
General considerations
Authors: Hallam A
Published: November 2023

This book is as much about scientists as ideas, or rather about the interaction of scientists with each other and the ideas they have argued about. Indeed, the recurring appearance in the text of leading scientists provides more of a link than the controversies that have been reviewed successively. It is an oversimplification if not a downright distortion to dub these figures radicals or reactionaries with respect to established theory, and any attempt to extend such a one-dimensional classification to those persons involved in more than one controversy is doomed. The transition through an individual lifetime from young turk to old fogey is in some cases clear to see.
The Evolution of Animal Mating Systems
Authors: Rees Jane A , Harvey Paul H
Published: November 2023

Attempts by evolutionary biologists to make sense of the natural diversity of animal mating systems typically employ observation, experiment, and theory. Inspection of the immense literature reveals that much of the work centres on interpreting mating systems within a long-standing tradition of evolutionary biology, that of sexual selection theory with its consequences for parental investment. As this chapter will illustrate, this approach has taken us a long way. But scientists cannot divorce themselves from their intellectual backgrounds and many studies have been coloured by inadequate theory. Indeed, incorrect assumptions underlying contemporary theory may have hindered the comprehension of mating systems as a whole. For example, it has often been assumed that variance in reproductive success among females is much less than that found among males. The general picture that emerged from making this assumption portrayed males as actively attempting to maximize the number of copulations they could achieve, while females were more choosy about who they mated with. It was also assumed that females bore the costs of reproduction almost exclusively. This was the paradigm that behavioural scientists were brought up on, so it is not surprising that their assumptions were not questioned when biased questions brought stock answers (perhaps the fact that similar sexual stereotypes exist in Western white middle-class culture made the errors less apparent). In more recent studies which have not made these assumptions, a somewhat different picture emerges.
Main circuit of brushless servomotors
Authors: Dote Yasuhiko , Hashimoto Yukio
Published: November 2023

The main circuit of a brushless servomotor is equipped with semiconductor devices capable of self-switching off and high-speed switching. They have been developed by applying the techniques of power electronics and micro-electronics and are classified into bipolar transistors, MOSFETs, GTOs, and SITs. They enable not only frequency control but also very rapid voltage and current wave generation very rapidly: in other words, they make possible the motor torque control, which is critical to motor controls. These power semiconductor switching devices are produced in modular form to be used in the main circuit, the configuration of which is shown in Fig. 5.1.
Examples of selection and application of brushless servomotors
Authors: Uchiyama Shunichi
Published: November 2023

Motors are indispensable for industrial equipments used in industry and everyday life. They come in a considerable number of varieties. In the past, the output of a single motor has often been distributed to several users. Today in the age of sophisticated automation, each actuator is frequently equipped with its own motor. Consequently, a wide range of information is required in selecting motors. This chapter will provide basic information necessary for machine designers in selecting optimal motors and to make optimal use of them.
General Introduction
Authors: Hendershot J R
Published: November 2023

A brushless motor, as its name suggests, is a motor without brushes, slip rings or mechanical commutator, such as are required in conventional DC motors or synchronous AC machines for connection to the rotor windings, [1,2]. Several motors satisfy this basic definition. The commonest is the AC induction motor, in which current in the rotor windings is produced by electromagnetic induction. As an AC motor, the induction motor employs a rotating magnetic field that rotates at a synchronous speed set by the supply frequency. However, the rotor rotates at a slightly slower speed because the process of electromagnetic induction requires relative motion, or slip, between the rotor conductors and the rotating field.
Magnetic Design
Authors: Miller TJE
Published: November 2023

The flux in a brushless permanent-magnet motor is established by the magnets. We have seen in Chapter 1 that the torque is proportional to the current and the flux, while the no-load speed is proportional to the voltage and inversely proportional to the flux. The flux is clearly a most important parameter in the design. This chapter describes the simplest methods of calculating it, for later use in the calculation of the EMF and torque equations and the speed/torque characteristic. The simplest motor is the 2-pok motor, Fig. 4.1. The flux is intended to link the coils of the phase windings on the stator, and these coils are located as close as possible to the magnet to minimize the amount of magnet flux that “leaks” from the N pole to the S pole without linking any turns of the windings.
Electronic Commutation Of Squarewave Motors
Authors: Miller TJE
Published: November 2023

This chapter describes the process of electronic commutation in squarewave brushless DC motors and their controllers. It also describes the differential equations used by the PCrBDC computer program for the dynamic simulation of 3-phase squarewave brushless DC motors, with wye, delta, and unipolar half-bridge connections. The commutation process is important for detailed understanding of the switching of the power transistors.
Magnetic Materials
Authors: Staton D A
Published: November 2023

This chapter reviews the material properties of permanent magnets, electrical steel and insulated wire. There is still widespread use of c.g.s. units in the magnet industry, whereas motors are usually designed in metric (SI) units in Europe and Japan, and in metric or mixed units in the USA. The most important magnetic conversion factors are given in Chapter 4. A brief description of the characteristics, parameters and equations associated with permanent magnets is given here, i.e. the normal and intrinsic hysteresis curves, major and minor loops, temperature effects, energy product, magnetization, etc. More detailed descriptions can be found in specialist works on permanent magnets, e.g. [1].
Artificial-intelligence-based switched reluctance motors, estimation, design, and control
Authors: Vas Peter
Published: November 2023

In a recent book [Vas, 1998], the fundamentals of switched reluctance motor drives were discussed together with various position estimators which can be used in position sensor less switched reluctance motor drives. Furthermore two main solutions for instantaneous torque-controlled switched reluctance motor drives have been discussed. The first solution uses profiled stator currents, and thus the drive contains a current controller, but the second solution uses profiled stator flux linkages, and the drive scheme contains a stator flux linkage controller. It has been shown that the second scheme is simpler to implement. Both schemes can operate in a wide speed range and offer the potential of using switched reluctance motors in many applications, where so far only other types of motors have been used.
Numerical methods for optimal control problems
Authors: Hocking Leslie M
Published: November 2023

Although a great deal can be learnt from closed-form solutions of optimal control problems, in general the solution of such problems can only be obtained by computation. Some numerical methods that can be used to solve optimal control problems are discussed in this chapter. Since the time-optimal principle TOP derived in Part A provides a criterion for the optimal control that is identical to that derived from the PMP as applied to time-optimal problems (see §9.1), we need only discuss the way in which the PMP can be implemented in a numerical solution of a general optimal control problem. The development of appropriate algorithms for such problems is fraught with obstacles, and it does not seem possible to produce schemes that will apply in general. Each problem, or class of problems, has to be considered on its own; all that can be done here is to describe methods that work in some specific cases.
3 How to compare two knots
Authors: Hemion Geoffrey
Published: November 2023

Let us consider the BASIC PLAN for solving the knot problem. The idea is very simple. It does not involve complicated algebraic structures. We need not burden ourselves with group theory, rings, modules, or polynomials. All that is needed is elementary common sense, combined with a few basic ideas from the theory of topology. Now as a basic philosophical principle the problem of comparing two complicated things with one another must always be reduced to the problem of comparing many simpler things. And in fact the simpler things must each be so simple as to allow the human (or even the mechanical) mind to compare them at a single glance. For example, let us imagine that we have two books, and the question arises as to whether or not they are the same. If their covers are different, then the problem has been solved; they are different. But even if the two books appear to be similar from the outside, still that is no guarantee that they are similar inside. The only way to be sure is to go through both of the books together and compare them, word for word—or even letter for letter. For this purpose, modern society has learned to appreciate the advantages of electronic computers.
Fundamental solutions
Authors: Hemion Geoffrey
Published: November 2023

We can apply this result in the theory of Diophantine inequalities to the basic plan for classifying Haken manifolds. Remember that the 3-manifold M consists of tetrahedrons—that is, a set of sets of four vertices. Furthermore, any normal surface consists of squares and triangles in the tetrahedrons. It is easy to see that any arbitrary normal surface can be completely specified by simply supplying a list of squares and triangles. But as far as the computer is concerned, a square is given by specifying which tetrahedrons Δ we are to take, and then specifying the way the square splits the four vertices into two pairs. In the case of the triangle we only need to specify the single vertex which is isolated from the other three by the splitting.
Why is the ‘difficult’ case difficult?
Authors: Hemion Geoffrey
Published: November 2023

It is true that the reader may have experienced difficulties in following the unwinding operations of the last chapter. Nevertheless, that is not the true difficulty. As far as programming the algorithm into our hypothetical computer is concerned, it is easy to set a somewhat larger—but finite—limit on the number of fundamental surfaces of zero complexity which are to be brought into consideration. The true difficulty lies in a completely different direction. As a matter of fact, I have neglected to mention a certain very critical detail. For let us think about the whole reduction process which is the basis of our plan for classifying knots. At each stage it involves splitting the given 3-manifold M along an incompressible surface, and in the process drawing lines along the newly-opened boundaries of the resulting 3-manifold, thereby giving a boundary pattern to aid us in gluing things back together again.
The hyperbolic plane
Authors: Hemion Geoffrey
Published: November 2023

To proceed, and in particular to understand the arguments in the Appendix, it is necessary to know a few facts about the hyperbolic plane. The hyperbolic plane is something of very great historical interest, so we will pause for two chapters in order to become acquainted with it. But to begin, let us go way back in the history of science and recall Euclid’s classical postulates of geometry.
The size of a homeomorphism
Authors: Hemion Geoffrey
Published: November 2023

In Chapter 15 it was shown that the problem of classifying Stallings fibrations is equivalent to the problem of classifying homeomorphisms of compact surfaces. Therefore we will concentrate on surfaces alone and allow ourselves to forget—for the time being at least-the more complicated problems which can occur in three dimensions. But even going beyond this, we will also rule out the case of compact surfaces without boundary. After all, a knot space does have a boundary to begin with. Then at each stage of the splitting of the knot space we must continue to deal with 3-dimensional pieces which have boundaries. On the other hand, a Stallings fibration over a surface without boundary must be a 3-manifold which itself has no boundary.
Small curves
Authors: Hemion Geoffrey
Published: November 2023

How can we prove that there is a number such as N of the previous chapter, which gives us a limit on the size of possible conjugating homeomorphisms which are to be investigated? Again, this question is too difficult to answer directly. The trick which I used was to first prove that a ‘small’ closed curve c must exist on the surface S. Now the idea of smallness is easy to define for curves on S. Let c be some arbitrary curve on S. The curve will be assumed to be closed, in the sense that its starting point is the same as its endpoint. Put another way, c is a mapping of the circle (the I-sphere) into S. We can assume that c is in general position with respect to the set of curves {ζ1, ... , ζn}. Then c generally passes through the fundamental region Δ of S in a number of arcs. The size of c is defined to be this number. Thus we shall say that c is small if its size is small.
Classifying mappings of surfaces
Authors: Hemion Geoffrey
Published: November 2023

Let f and g be two given homeomorphisms of a surface S onto itself. We have seen in Chapter 18 that homeomorphisms can be described in terms of lists of numbers. Furthermore the lengths of these lists are no greater than the size of the homeomorphism. The question is, does there exist a further homeomorphism h: S→ S such that f is isotopic to h-1  gh? According to the reasoning of the last chapter, we can find a definite (but large) number M(f, g), which depends only on the sizes of the known homeomorphisms f and g, such that if there exists a conjugating homeomorphism, then there also exists one of size no greater than M(f, g). (This is the number referred to as N in Chapter 18.) It is now, in principle at least, a simple matter to go through and check all possible homeomorphisms of size less than this number, looking for some conjugating homeomorphism. Our hypothetical computer will be set the task of going through all lists of lists with no more than M(f, g) entries. Of course it is true that most lists which might be chosen at random will not represent homeomorphisms of the surface. A number of rules will have to be formulated to identify lists which do, in fact, represent homeomorphisms. Furthermore, combinatorial rules will have to be formulated to identify a conjugating homeomorphism during the search. These are routine tasks which we can leave to the hypothetical programmer of our hypothetical computer.
The final result
Authors: Hemion Geoffrey
Published: November 2023

We are left with the task of relating this theory to the argument of Chapter 13. As we have seen in Chapter 3, the classification algorithm involves splitting 3-manifolds along incompressible surfaces to obtain, in the end, 3-cells with boundary patterns. This works fine except in the case that a piece suddenly appears which is a Stallings fibration containing no incompressible tori. How does the computer know when it is dealing with this case? Let M be the given 3-manifold which we know is a Stallings fibration.
Interpolation and Approximation
Authors: Kockler Norbert
Published: November 2023

This chapter will show the different possibilities of approximating a given function or set of data points by a linear combination of (simple) functions taken from a certain function system.
Numerical Integration
Authors: Kockler Norbert
Published: November 2023

In many applications the evaluation of definite integrals - also called quadrature - is part of a mathematical problem. Often quadrature cannot be done analytically, or it is too complicated within a program with a large number of modules running. In such cases numerical integration is necessary.
From Finite To Infinite Sampling Series
Authors: Higgins J R
Published: November 2023

An interesting question, which has come up from time to time in the research literature, is whether sampling theorems involving infinitely many sampling points can be derived as limiting cases of finite sampling theorems. Indeed, the cardinal series arises as a formal limiting case of the finite Lagrange formula (the right-hand side of (1.2.1)), as we shall mention in a moment; but a fully rigorous treatment of this limiting procedure was not given until very recently. The present chapter is devoted entirely to the discussion of this problem by Hinsen and Klösters (1993).
Sampling For Bernstein And Paley-Wiener Spaces
Authors: Higgins J R
Published: November 2023

Before studying the basic sampling theories for these classes we need preliminary definitions about entire functions of exponential type, and some principles for working with Bernstein classes. This occupies §6.1; no proofs are given here, but references to standard sources are included.
Examples of Ockham algebras; the Berman classes
Authors: Blyth T S , Varlet J C
Published: November 2023

Recall that a distributive Ockham algebra is an algebra (L; ∧, v,f, 0, 1) of type (2, 2, 1 , 0, 0) in which (L; /\, V, 0, 1) is a bounded distributive lattice and x  ↦ f(x) is a unary operation such thatf(0) = 1, f(l) = 0 and Without explicit mention to the contrary, all the Ockham algebras that we shall deal with will be distributive as lattices so we shall agree to drop the adjective ‘distributive’ and talk of an Ockham algebra. We shall often also denote this by the simpler notation (L;f).
Congruences on double MS-algebras
Authors: Blyth T S , Varlet J C
Published: November 2023

We now turn our attention to congruences on double MS-algebras. Here also an important role is played by the principal congruences ϑ (a, b) with a≤ b. It is clear from Theorem 2.1 that if L∈ DMS and a, b ∈ L are such that a ≤b then we have [ueq]Arguing precisely as in Theorem 8.1, we can characterise ϑ(a, b) as follows.
SecE
Authors: Flower A M , Silhavy T J
Published: November 2023

Additional alleles of sec£ were isolated as signal sequence suppressors designated prlG alleles. Starting with a strain that was dextrin negative due to a mutation in the signal sequence of LamB (maltoporin), these suppressors were identified following selection for the ability to use dextrin as a carbon source.
SecD and SecF
Authors: Pogliano K J , Beckwith J
Published: November 2023

Mutations within the secD locus were selected by their ability to cause internalization of an alkaline phosphatase-galactosidase fusion protein or to cause the induction of the secA gene1-2-3. Conditionally-lethal (cold-sensitive) and non-conditional mutations have been detected. Both classes of mutants accumulate the precursors of exported proteins at the permissive temperature of 37°C, and this secretion defect rapidly becomes worse at 23°C4. secD and secF mutants are indistinguishable except by complementation. It has been observed recently that null mutations lacking secD and secF are cold-sensitive for growth and have a severe protein export defect5. Overexpression of Sec D and SecF improves the export of proteins with defective signal sequences5.
SEC62
Authors: Deshaies R
Published: November 2023

sec62 mutants were originally identified in a selection for conditional lethal mutants that fail to localize a signal peptide-containing His4 chimera to the ER lumen1. Various derivations of this selection scheme have yielded mutant alleles of three other genes: sec611(see p. 31), sec632(see p. 34), and sec653(see p. 28). sec62 mutants accumulate untranslocated precursor forms of several secretory pathway polypeptides, including alpha factor and carboxypeptidase Y. The translocation of some proteins, including invertase, is only weakly affected by the sec62 mutation, whereas others, including dipeptidylaminopeptidase B, are not affected at aII. Whereas sec62 cells are temperaturesensitive for growth, they exhibit severe defects in protein translocation even at the “permissive” temperature of 24°C. Growth at lower temperatures (17°(), however, restores translocation to nearly wild type levels2. Deletion of SEC62 is lethaI4, indicating that it is an essential gene.
SEC63
Authors: Feldheim D A
Published: November 2023

Temperature-sensitive, conditionally-lethal sec63 mutants were identified by a genetic selection for mutant yeast cells that fail to translocate a signal peptide-cytosolic enzyme hybrid protein3 sec63 accumulates in the cytosol the precursor forms of a variety of soluble secretory and vacuolar precursors. Null alleles of SEC63 are inviable at all temperatures, indicating that this gene is essential.
SEC66
Authors: Fcldheim D A
Published: November 2023

Sec66p was identified as a 31.5 kDa glycoprotein that coprecipitated in an immune complex with Sec62p when radiolabeled, detergent solubilized membrane proteins were immunoprecipitated with anti-Sec62p antibodies under non-denaturing conditions2 Subsequently, it was shown that anti-Sec63p antibodies could also co-immune precipitate Sec66p3. Native Sec66p was purified in quantities suitable for microsequencing using large scale immunoprecipitation. HSS1 was isolated as an allelespecific high copy suppressor of sec63-1011 HSS1 was cloned and sequenced and found to be identical to SEC66.
SEC70
Authors: Green N
Published: November 2023

Mutants were isolated based on their inability to insert into the membrane of the ER a membrane-bound fusion protein consisting of the N-terminal 255 residues of arginine permease and the complete histidinol dehydrogenase sequence encoded by the HIS4C region of HIS412Three independent mutants, secl0-2, secl0-3 and secl0-4, inefficiently translocated the histidinol dehydrogenase portion of the fusion protein across the ER membrane. However, these mutant alleles showed little or no inhibition of the translocation of the dehydrogenase when it was placed behind only the N-terminal 189 residues of arginine permease.
SEC53
Authors: és F K ép
Published: November 2023

Temperature-sensitive, conditionally-lethal sec53 mutants were selected on the basis of accumulation of inactive precursors of secreted proteins2. Temperature-sensitive a/g4 mutants were selected by their survival after a prolonged exposure to tritiated mannose. Cells that efficiently incorporated the labeled sugar were killed by self-irradiation. The best characterized sec53 allele, sec53-6, shows the strongest phenotype. At restrictive temperature, sec53-6, like alg4-9, accumulate inactive and incompletely glycosylated forms of secretory proteins within the lumen of the ER.
α,-glucosidase I
Authors: Trimble R , Moremcn, K , Herscovics A
Published: November 2023

Studies on partially1 and fully2 purified a-glucosidase from S. cerevisiae membrane preparations demonstrated that this enzyme removes a single glucose residue from Glc3Man9GlcNAc2. The enzyme, which has a subunit molecular mass of 95 kDa, has a pH optimum of 6.4-6.8 and does not act on aryl a-glucosides.
Docking protein/SRP receptor
Authors: Meyer D I
Published: November 2023

A 60 kDa proteolytic (elastase) fragment of docking protein (DP) originally isolated from canine pancreatic rough microsome was found to be required for protein translocation across ER membranes in cell-free assays12. Antibodies raised against the purified fragment were used to identify the parent molecule, an ER membrane protein with an apparent molecular weight of 72 kDa3 Functional studies revealed that docking protein was able to release the SRPmediated translational arrest in wheat germ lysate4,5 On the basis of this activity, Gilmore and colleagues independently isolated the intact, 72 kDa form from detergent-solubilized membranes by SRP-affinity chromatography.