Showing papers by "University of Glasgow published in 1972"

The aromatic sextet

Abstract: The use of different spectra (UV, visible and NMR spectra) is demonstrated for the identification of polycyclic hydrocarbons.

Habitat Selection by Aquatic Invertebrates

Abstract: Publisher Summary This chapter focuses on habitat selection by aquatic invertebrates. It explains why animals are found in certain habitats and not in others, and it is restricted to a consideration of habitat selection by marine and freshwater invertebrates as revealed by experimental analysis. Habitat selection is essentially the relationship between behavior and environment, and it largely determines the local distribution of animal species. On the larger scale of geographical distribution, it is as yet uncertain how important habitat selection is, although it almost certainly plays a significant role. The chapter discusses the physical and chemical environment of intertidal animals, marine animals, freshwater animals, and interstitial animals. The reactions of animals to their biological environment and the part these play in habitat selection are very varied. Animals are continuously assessing the suitability of their environment and moving from place to place so that they can take best advantage of the range of conditions available to them. The behavioral mechanisms by which animals select their habitats, light reactions, gravity responses, gregariousness, and so on, have been covered in the chapter. Habitat preferences may remain fixed throughout the life span of an animal, or they may alter depending upon its physiological state, its age, its previous experience and learning, or its past and present environment. The marked variation in behavior shown by individuals of some species has been discussed along with the possible ways in which animals may colonize new habitats and to the part habitat selection might play in the origin of new species.

Simplified Colorimetric Determination of Thiocyanate in Biological Fluids, and Its Application to Investigation of the Toxic Amblyopias

Abstract: A colorimetric procedure for determination of small amounts of cyanide and thiocyanate, involving the synthesis of a pyridine dyestuff by the reaction of pyridine and an aromatic amine, has been simplified for the estimation of thiocyanate alone in biological fluids. Replacement of benzidine with p -phenylenediamine in the colorimetric reaction has both improved the precision of the analytical procedure and avoided a carcinogenic hazard. This method has been used to follow the decrease in plasma thiocyanate associated with abstinence from cigarette smoking, and its subsequent increase upon resumption. It has also been used to measure the plasma and urinary thiocyanate concentrations of patients suffering from the particular toxic amblyopias—tobacco amblyopia and Leber’s hereditary optic atrophy— believed to be associated with cyanide toxicity, and to follow the increased thiocyanate concentrations that accompany significant improvements in the patients’ vision brought about by various treatments.

The directivity and polarisation of thick target X-ray bremsstrahlung from solar flares

Abstract: The directivity and polarisation of solar hard X-ray bursts is discussed in terms of two bremsstrahlung source models. These involve continuous and impulsive injection of electrons respectively, as described widely in the literature.

Temperature-sensitive mutants of adenovirus defective in interferon induction at non-permissive temperature.

Abstract: SEVERAL different types of human adenoviruses induce interferon in chick embryo cells1,2 and it has been proposed that the penton antigen of the virus is responsible for this1. The evidence supporting this hypothesis, however, depends chiefly on sensitivity to trypsin, and in our opinion the adenovirus functions responsible for inducing interferon have not been clearly identified. We have isolated temperature-sensitive (ts) mutants of adenovirus type 53, which provided us with a possible system for identifying these functions. With this view in mind, we have tested ten ts mutants, classified into nine complementation groups4, for their ability to induce interferon in chick embryo cells at both the permissive (31° C) and non-permissive (38° C) temperatures. This brief communication presents evidence that two of these mutants, which complement each other in their ts functions, do not induce interferon at the non-permissive temperature, but induce it at the permissive temperature.

Nervous control of walking in the crab, Cardisoma guanhumi

Abstract: 1. Discharge patterns in the motoneurons innervating the propodite stretcher and bender muscles and dactylopodite opener and closer muscles of the legs of the land crab, Cardisoma guanhumi, were recorded during sideways walking on a styrofoam wheel (Fig. 1). 2. Rhythmic bursts of activity in these motoneurons can be correlated with leg movements during walking in both leading and trailing legs (Figs. 2, 3A, B, D). Similar patterns of activity can be recorded in animals freely walking on a bench (Fig. 3C). 3. These motor output patterns are quite different from those occurring in the same motoneurons during resistance reflexes. In particular, the shared openerstretcher excitor and the stretcher inhibitor show no preferential phase relationship during walking (Figs. 4, 5). It appears that the normal movements of the propo-dactylopodite (P-D) joint during walking do not give rise to resistance reflexes. 4. Opening and closing movements of the P-D joint, manually imposed during walking, induce resistance reflexes (Figs. 6, 7). Reflexes tend to be stronger, both in terms of number of impulses and impulse frequency, when the imposed movement opposes rather than reinforces ongoing P-D movements. 5. Animals walking sideways on the wheel with the P-D joint clamped rigidly in a stable position show only slight changes in their motor output patterns from those seen during normal walking (Fig. 3E). 6. A model is discussed in which the proprioceptive input resulting from the normal movements of the P-D joint during walking is inhibited centrally and so does not give rise to a resistance reflex. 7. These results clearly indicate that resistance reflexes do not play an important role in coordination of antagonistic muscles during walking. Instead it is likely that their primary function is to compensate for changes in the load applied at a joint as would occur on steep inclines and irregular surfaces.

Theory and design of periodic couplers.

Abstract: The theory of periodic couplers is examined from the point of view of the reciprocity theorem and a modified Born scattering approach. Design equations for several coupler configurations are presented. Efficiency and aperture size calculations are compared with previously published data for grating and Bragg couplers.

Zircon U-Pb ages of granulites from the Central Region of the Lewisian, northwestern Scotland

Abstract: The overprinting of the high grade rocks of the Scourian episode, during the Inverian and Laxfordian episodes, has so far prevented a reliable estimate being made of the age of the Scourian granulite–facies metamorphism in the Central Region of the Lewisian of northwestern Scotland. In an attempt to solve this problem the U–Pb isotopic systems of zircons from two samples of hypersthene granulite from the Kylesku group have been examined. These zircons have discordant apparent ages complicating the interpretation of the results. However, by measuring a number of size fractions from each of the two zircon suites it has been possible to demonstrate that a major isotopic event or events took place approximately 2700 m.y. ago in these granulite–facies rocks. It has also been shown that the two discordance trends found for the two zircon populations can be explained in terms of episodic disturbances of the U–Pb isotopic systems at times which correspond to the known ages of ‘Laxfordian’ and ‘Caledonian’ events.

Maturation Pathway for Ribosomal RNA in the Hela Cell Nucleolus

Abstract: The maturation pathway for ribosomal RNA in Hela cells has been confirmed by RNA sequencing methods.

The development of Hymenolepis diminuta in primary and secondary infections in mice.

Abstract: Over 90% of Hymenolepis diminuta cysts administered by stomach tube become established in CFLP, and Porton strains of mice. The rate of growth of single worm infections in terms of dry weight and length was determined. The rate of growth of H. diminuta in mice is slower than in rats even in worms only a few mm long. In most mice growth ceases abruptly on day 10±1 day when the worm is 4–30 cm long, destrobilation usually occurs leaving a scolex and neck often 0·5–2 mm in length. Destrobilated worms can survive for at least 47 days but little if any regrowth occurs unless the worms are surgically transplanted into rats or previously uninfected mice. Normal growth appears to be resumed within hours in both recipient hosts. The cause of destrobilation is probably not physiological; position of establishment and forward migration during growth of the worm in mice is similar to that in a rat. Destrobilation occurs well before the worm fills the small intestine lengthwise. Strong evidence of an immunological response being involved is given by the fate of a secondary infection given 22 and 28 days after the primary. Lower % recoveries were recorded in secondary infections killed 6–9 days later, and the worms were severely stunted. The various lines of evidence are discussed and it is concluded no reasonable doubt exists that H. diminuta is rejected by CFLP and Porton mice as a result of an immunological response.

The canine stifle joint I. Rupture of the anterior cruciate ligament

Abstract: A method of assessment of cases of rupture of the anterior cruciate ligament with a view to prescribing either surgical or conservative treatment is described. The results of treatment of the cases after such an assessment indicates that the majority of small dogs will recover to satisfactory function after 2 months enforced rest, but large breed and working dogs require surgical intervention for successful treatment. Resume. Les auteurs decrivent une methode propre a evaluer les ruptures du ligament cruci-forme anterieur en vue de prescrire soit l'intervention chirurgicale, soit le traitement conserva-teur. Les resultats therapeutiques obtenus sur la base de cette evaluation portent a conclure que chez le chien de petite taille, 2 mois de repos force permettent le plus souvent d'obtenir un retablissement fonctionnel satisfaisant, tandis que chez les chiens de grande taille et chiens d'utilite, l'intervention chirurgicale s'impose. Zusammenfassung. Es wird eine Methode zur klinischen Beurteilung von Fallen einer Ruptur des vorderen Kreuzbandes im Hinblick auf die Moglichkeit einer chirurgischen oder konservativen Behandlung beschrieben. Die Behandlungsergebnisse bei den Fallen nach einer solchen Beurteilung zeigen, dass die Mehrzahl von kleinen Hunden sich in 2 Monaten Zwangsruhe zu einer zufriedenstellenden Funktion erholt, grosse Rassen und Arbeitshunde aber einen chirurgischen Eingriff zur erfolgreichen Behandlung benotigen.

Acoustic-surface-wave amplitude and phase measurements using laser probes

Abstract: The investigation of acoustic-field distributions on free surfaces is important in several different classes of application. Measurements of the phase of acoustic surface waves using optical probes allow direct measurement of their velocity. A number of different optical-probe types are compared on the basis of sensitivity and stability. The operation and design of an optical heterodyne probe, capable of high-precision phase and group-velocity measurement, is described.

The skull and skeleton of Eogyrinus attheyi Watson (Amphibia: Labyrinthodontia)

Abstract: As a preliminary to the redescription of the anatomy ofEogyrinus attheyi Watson, an account is given of the problems of nomenclature of British members of the anthracosaur family Eogyrinidae to which it belongs. There is no evidence to show that the four named genera of British eogyrinids differ from one another in any significant feature not explicable by allometric growth. Reconstruction of a series of allometric curves based on known skull specimens allows estimation of the dimensions of incomplete specimens. The skulls then fall into four size groups which correspond, with some stratigraphical backing, to the four named genera. The lectotype skull of Eogyrinus, from the Low Main Seam, Newsham, Northumberland, has been cleaned using an ' Airbrasive' unit and is used as the basis of a new description of the skull. Additional information is provided by other Newsham specimens and two skulls from the Middle Coal Measures of Lanarkshire. The skull is completely known and is typical of anthracosaurs. The skull roof is closely similar to that of the eogyrinid Palaeoherpeton (' Palaeogyrinus'), but no anterior tectal bone is present above the naris in Eogyrinus. The nature of the dermal ornament is fully described. The palate is Wpically anthracosaur, with toothless vomers, a 'tusk-pair' on each palatine and ectopterygoid, and additional small ectopterygoid teeth. The pterygoids descend below the level of the jaw line posteriorly as in Palaeoherpeton. The braincase is reconstructed from an isolated Newsham specimen, originally attributed by Watson, from the lectotype and from one of the Scottish skulls. The isolated specimen shows the course of the semicircular canals as well as the fenestra ovalis. Most of the cranial nerve foramina are present. A complete reconstruction of the lower jaws is possible both as single rami and in articulation. Description of the jaw articulation allows a reconstruction of the relative movements of the rami in opening and closure. The only associated material of the appendicular skeleton is the lectotype left femur, but an interclavicle from Newsham is certainly eogyrinid and probably pertains to Eogyrinus. Isolated ventral scales are described and their pattern of articulation reconstructed. The material described in this paper is combined with that used in an earlier account of the axial skeleton to give a reconstruction of the whole skeleton of Eogyrinus in articulation, together with a restoration of the appearance of the living animal.

Carbohydrates of the hepatopancreas and blood tissues of Carcinus

Abstract: 1. 1. A detailed comparative analysis of the carbohydrates in the haemolymph and hepatopancreas of Carcinus maenas has been made. 2. 2. Glucose, trehalose, maltose, fructose and fucose were identified in both tissues by thin-layer chromatography (TLC). Glucosamine was present in the hepatopancreas but absent from blood. Chromatography of polysaccharide hydrolysates suggest that glycogen and chitin are constituents of both tissues. 3. 3. Polysaccharides, including glycogen, predominate in the haemolymph constituting 75–80 per cent of the circulating carbohydrates. Conversely, polysaccharide, and particularly glycogen, values were low in the hepatopancreas, being no more than 10–20 per cent of the total tissue carbohydrate. 4. 4. Quantitative records were supported by radioactive tracer studies which showed that the highest levels of 14 C-glucose activity were incorporated into blood polysaccharide fractions. 5. 5. A possible carbohydrate storage and synthetic function for Carcinus haemocytes is suggested.

The rate of turnover of the adenosine triphosphate pool of Escherichia coli growing aerobically in simple defined media.

Abstract: 1. Methods are described for measuring the ATP pool in batch cultures of bacteria and of computing the rate of ATP synthesis from the rates of oxygen consumption and substrate utilisation. 2. The ATP pool of Escherichia coli (ML 308) growing aerobically at the expense of a variety of single carbon sources falls within the range 4.5–7.5 μmoles/g dry wt of cells. On any given compound the pool is constant during logarithmic growth. There is no simple relationship between growth rate and the size of the ATP pool. 3. The rate of synthesis of ATP is also constant during logarithmic growth and falls within the range 1.7–2.4 mmoles/g dry wt/min, assuming a P/2e ratio of 3. 4. During logarithmic growth the rate of turnover of the ATP pool falls within the range 250–450 times min-1. 5. Alterations in rate of growth and ATP synthesis occur simultaneously. These changes can be large and rapid (e.g. on exhaustion of a limiting nutrient) but are not reflected in the rate of change of the ATP pool which is much slower.