Showing papers by "University of Glasgow published in 1991"
Book•
26 Apr 1991TL;DR: In this article, the basic ingredients of a family of simple elastic-plastic models of soil behaviour are described and used in numerical analyses. But the models on which this book concentrates are simple, understanding of these will indicate the ways in which more sophisticated models will perform.
Abstract: Soils can rarely be described as ideally elastic or perfectly plastic and yet simple elastic and plastic models form the basis for the most traditional geotechnical engineering calculations. With the advent of cheap powerful computers the possibility of performing analyses based on more realistic models has become widely available. One of the aims of this book is to describe the basic ingredients of a family of simple elastic-plastic models of soil behaviour and to demonstrate how such models can be used in numerical analyses. Such numerical analyses are often regarded as mysterious black boxes but a proper appreciation of their worth requires an understanding of the numerical models on which they are based. Though the models on which this book concentrates are simple, understanding of these will indicate the ways in which more sophisticated models will perform.
1,671 citations
TL;DR: In this paper, the difficulties of learning science are related to the nature of science itself and to the methods by which science is customarily taught without regard to what is known about children's learning.
Abstract: The difficulties of learning science are related to the nature of science itself and to the methods by which science is customarily taught without regard to what is known about children's learning. An information processing model is proposed to guide thinking and research in this area.
1,045 citations
TL;DR: It is proposed that electrons captured from the barriers in the upper levels of quantum boxes are retained in their cascade to the fundamental states for more than nanoseconds, and no luminescence can be obtained from these stored electrons with reasonable assumptions for the hole population.
Abstract: The poor radiative efficiency in quantum-box luminescence is tentatively explained as an intrinsic effect rather than the usually invoked effect of etch damages From the recently calculated decreased relaxation rate in zero-dimensional (0D) systems under 100\char21{}200-nm lateral quantization, we propose that electrons captured from the barriers in the upper levels of quantum boxes are retained in their cascade to the fundamental states for more than nanoseconds Due to the mutual orthogonality of quantum states in a box, no luminescence, or much less than in 2D or 3D, can be obtained from these stored electrons with reasonable assumptions for the hole population Magnetic-confinement experiments in quantum-well lasers support our conclusion A realistic model at low temperature describes more quantitatively the observed strong decay of the radiative efficiency in quantum boxes and pseudowires with decreased lateral dimensions
744 citations
TL;DR: In this article, a modified boundary layer formulation based on the first two terms K and T, of the elastic field, is proposed for plane-strain elastic-plastic crack-tip fields.
Abstract: Plane-strain elastic-plastic crack-tip fields have been modeled with modified boundary layer formulations based on the first two terms K and T, of the elastic field. Geometries which maintain J-dominance are characterized by zero or positive T stresses, while geometries with negative T stresses can be described by a two-parameter characterization using J and T into full plasticity
633 citations
TL;DR: The paper also touches on possible mechanisms for the "protective action" of selenium against mercury toxicity and deals briefly with the synergism between the two elements.
543 citations
TL;DR: It is clear that topography on this scale can control cell behaviour, but guidance of this type is strongly dependent on cell type and cell-cell interactions.
Abstract: Laser holography and microelectronic fabrication techniques have been employed to make grating surfaces in fused quartz with ultrafine period (260 nm) in an attempt to mimic the topography of aligned fibrillar extracellular matrix (ECM), which, in the past, has been shown to affect the behaviour of cells in vitro and in vivo. The alignment of BHK cells, MDCK cells and chick embryo cerebral neurones on 260 nm period grating surfaces (130 nm grooves separated by 130 nm) of various depths (100, 210 and 400 nm) was examined. While all gratings aligned BHK cell populations, the degree of alignment was dependent on depth. The response of single MDCK cells to the grating patterns was both to align precisely to the direction of the gratings, and to elongate; only their elongation was depth-dependent. MDCK cells that were part of epithelial cell islands, and the outgrowth of neurites from chick embryo neurones, were mainly unaffected by the grating surfaces. It is clear that topography on this scale can control cell behaviour, but guidance of this type is strongly dependent on cell type and cell-cell interactions.
492 citations
TL;DR: Both TGF beta 1 and beta 2 transcripts are seen in regions actively undergoing cardiac septation and valve formation, suggesting some interaction of these growth factors in this developmental process.
Abstract: We have compared the expression of the genes encoding transforming growth factors beta 1, beta 2 and beta 3 during mouse embryogenesis from 9.5 to 16.5 days p.c. using in situ hybridisation to cellular RNAs. Each gene has a different expression pattern, which gives some indication of possible biological function in vivo. All three genes appear to be involved in chondroossification, though each is expressed in a different cell type. Transcripts of each gene are also present in embryonic epithelia. Epithelial expression of TGF beta 1, beta 2 and beta 3 RNA is associated with regions of active morphogenesis involving epithelial-mesenchymal interactions. In addition, widespread epithelial expression of TGF beta 2 RNA can be correlated with epithelial differentiation per se. The localisation of TGF beta 2 RNA in neuronal tissue might also be correlated with differentiation. Finally both TGF beta 1 and beta 2 transcripts are seen in regions actively undergoing cardiac septation and valve formation, suggesting some interaction of these growth factors in this developmental process.
490 citations
01 Sep 1991
TL;DR: In this paper, a novel technique, directly using artificial neural networks, is proposed for the adaptive control of nonlinear systems, where the ability of neural networks to model arbitrary nonlinear functions and their inverses is exploited.
Abstract: A novel technique, directly using artificial neural networks, is proposed for the adaptive control of nonlinear systems. The ability of neural networks to model arbitrary nonlinear functions and their inverses is exploited. The use of nonlinear function inverses raises questions of the existence of the inverse operators. These are investigated and results are given characterising the invertibility of a class of nonlinear dynamical systems. The control structure used is internal model control. It is used to directly incorporate networks modelling the plant and its inverse within the control strategy. The potential of the proposed method is demonstrated by an example.
372 citations
TL;DR: The method of regularization is portrayed as providing a compromise between fidelity to the data and smoothness, with the tradeoff being determined by a scalar smoothing parameter.
Abstract: The method of regularization is portrayed as providing a compromise between fidelity to the data and smoothness, with the tradeoff being determined by a scalar smoothing parameter. Various ways of choosing this parameter are discussed in the case of quadratic regularization criteria. They are compared algebraically, and their statistical properties are comparatively assessed from the results of all extensive simulation study based on simple images. >
342 citations
TL;DR: The very complexity of such systems, together with the need of the cell to monitor and respond to a variety of external stimuli, poses the question as to what overall controls are placed upon these various transduction mechanisms and how they might relate to each other.
Abstract: Over the past 20 years we have seen a phenomenal increase in our understanding of the diversity and the molecular mechanism of action of signal transduction systems. Now we are faced with a cell being provided with a myriad of cell surface receptors, each connected to particular signal transduction systems. The very complexity of such systems, together with the need of the cell to monitor and respond to a variety of external stimuli, poses the question as to what overall controls are placed upon these various transduction mechanisms and how they might relate to each other. At one extreme, we can envisage that pathways might be isolated completely from each other and thus function in an an apparent ‘vacuum’. On the other hand, we can envisage ‘cross-talk’ between the various pathways linking each into an adaptable network array. Such a network, linking distinct signalling systems, would offer the cell a sophisticated ability to sense multiple environmental signals impinging upon it, thus providing a means of adapting or regulating its response to a particular range of effectors.
308 citations
TL;DR: In this paper, the effect of the T-stress on the small-scale yielding field of a crack in plane strain conditions has been examined using modified boundary layer formulations, where numerically calculated stresses at the crack tip are represented by slip line fields for small-strain theory.
Abstract: The effect of the T-stress on the small-scale yielding field of a crack in plane strain conditions has been examined using modified boundary layer formulations. The numerically calculated stresses at the crack tip are represented by slip line fields for small-strain theory. Positive T-stresses cause plasticity to envelop the crack tip and exhibit a Prandtl field, corresponding to the limiting solution of the HRR field for a nonhardening material. Moderate compressive T-stresses reduce the direct stresses within the plastic zone by decreasing the hydrostatic stress by T. This causes a loss of J-dominance, and a stress distribution represented by an incomplete Prandtl field.
TL;DR: It is shown that, for all transporters, the transport of 2-deoxy-D-glucose is inhibited by D-but not by L- glucose, and both D-galactose and D-mannose are transported by GLUTs 1-3 at significant rates; furthermore, GLUT 2 is capable of transporting D-fructose.
Abstract: We describe the functional expression of three members of the family of human facilitative glucose transporters, the erythrocyte-type transporter (GLUT 1), the liver-type transporter (GLUT 2), and the brain-type transporter (GLUT 3), by microinjection of their corresponding mRNAs into Xenopus oocytes. Expression was determined by the appearance of transport activity, as measured by the transport of 3-O-methyl-D-glucose or 2-deoxy-D-glucose. We have measured the Km for 3-O-methyl-D-glucose of GLUTs 1, 2, and 3, and the results are discussed in light of the possible roles for these different transporters in the regulation of blood glucose. The substrate specificity of these transporter isoforms has also been examined. We show that, for all transporters, the transport of 2-deoxy-D-glucose is inhibited by D-but not by L-glucose. In addition, both D-galactose and D-mannose are transported by GLUTs 1-3 at significant rates; furthermore, GLUT 2 is capable of transporting D-fructose. The nature of the glucose binding sites of GLUTs 1-3 was investigated by using hexose inhibition of 2-deoxy-D-glucose uptake. We show that the characteristics of this inhibition are different for each transporter isoform.
TL;DR: This article investigates whether changes in antioxidant systems contribute to pregnancy-induced hypertension by testing two extracellular (plasma thiols and ceruloplasmin) and two intracellular (red blood cell lysate thiolS and red blood cell superoxide dismutase) antioxidant markers.
TL;DR: The experiments on attachment lend general support to the theory that toe pads stick by wet adhesion, supported both by observations of peeling in single toe pads of anaesthetised frogs and by the inability of frogs to adhere to vertical surfaces in a head-down orientation.
Abstract: Summary The mechanisms by which the toe pads of tree frogs adhere to and detach from surfaces during climbing have been studied in Osteopilus septentrionalis and other tree frogs using a variety of techniques. The experiments on attachment lend general support to the theory that toe pads stick by wet adhesion. First, the presence of a meniscus surrounding the area of contact shows that pad and surface are connected by a fluid-filled joint. Second, experiments on single toe pads of anaesthetised frogs demonstrate that the pads exhibit the velocity-dependent resistance to shear forces expected of any system employing a fluid as an adhesive mechanism. Third, the largest adhesive forces that toe pads can generate (approx. 1.2mNmm~ 2 , calculated from data on sticking ability) are within the range that can be produced by wet adhesion. Simple measurements of the forces needed to separate a pair of metal discs joined by mucus demonstrate that both viscous forces (Stefan adhesion) and surface tension (the two components of wet adhesion) are likely to play significant roles in the tree frog's adhesive mechanism. The experiments on detachment demonstrate that toe pads are detached from surfaces by peeling, the pads being removed from the rear forwards during forward locomotion up a vertical surface. When the frogs were induced to walk backwards down this vertical slope, peeling occurred from the front of the pad rearwards. Use of a force platform to measure directly the forces exerted by the feet during climbing shows that, during forward locomotion up a vertical slope, this peeling is not accompanied by any detectable detachment forces. Such forces of detachment are seen, however, during backward walking down the slope and when belly skin comes into contact with the platform. That peeling occurs automatically during forward locomotion is supported both by observations of peeling in single toe pads of anaesthetised frogs and by the inability of frogs to adhere to vertical surfaces in a head-down orientation. Indeed, frogs on a rotating vertical surface were observed to adjust their orientations back towards the vertical whenever their deviation from the vertical reached 85.1 ±21.5°. During forward locomotion peeling seems to occur as a natural consequence of the way in which the toes are lifted off surfaces from the rear forwards, while during
TL;DR: In this paper, the authors showed that edge-cracked bars with a W ratios less than 0.3 in bending and 0.5 in tension lose Jdominance and are associated with the development of plasticity to the cracked face.
Abstract: Edge-Cracked bars with a W ratios less than 0.3 in bending and 0.5 in tension are shown to lose Jdominance. The loss of single parameter characterization is associated with the development of plasticity to the cracked face. Deeper cracks, for which plasticity develops through the ligament without spreading to the cracked face maintain J-dominance into large scale plasticity. The loss of J-dominance is attributed to compressive T-stresses, while geometries which exhibit tensile T-stresses retain J-dominance in accord with modified boundary layer formulations. The solutions for all the geometries can be characterized by J and Tinto large-scale plasticity.
TL;DR: A plasmid was reisolated which transformed A. nidulans at a frequency of 20,000 transformants per 10(6) protoplasts at near saturation levels of transforming DNA, representing a 250-fold enhancement of transformation efficiency over that found for typical integrative vectors such as pILJ16, theplasmid used in gene bank constructions.
TL;DR: This article reviewed the evolution of family changes within the first 15 years after head injury and identified some of the patient and family variables that predict the adequacy of family coping, before considering the nature and effectiveness of attempts to improve family coping.
Abstract: Many researchers and clinicians have commented on family disturbances after head injury, showing that such changes can be severe, functionally significant, and prolonged. However, little is known about the detailed nature and mechanisms of such changes, and there are many unresolved issues in the literature including the specification of the natural history of such changes (is there a consistent natural history?), and the prediction, consequences, and management of such changes. This paper reviews the evolution of family changes within the first 15 years after injury, and identifies some of the patient and family variables that predict the adequacy of family coping, before considering the nature and effectiveness of attempts to improve family coping.
TL;DR: There was a progressive and pronounced reduction in the concentrations of mercury found in the primary feathers as the growth sequence progressed, and these figures allow a more quantitative approach to measuring mercury pollution.
Abstract: Distribution of mercury between tissues was investigated in black-headed gull (Larus ridibundus) chicks fed doses of methyl mercury. Mercury accumulated differentially in the internal tissues, concentrations in the kidney exceeding those in the liver, which in turn exceeded those in the muscle. All feather types contained higher mercury concentrations than internal tissues. For each dose group, there was a progressive and pronounced reduction in the concentrations of mercury found in the primary feathers as the growth sequence progressed. The amount of mercury given to the birds affected the proportion of mercury deposited in the kidney, carcass, and primaries. The amount of mercury administered had no effect on the proportion of mercury excreted either in the faeces or the feathers. 71% of the doses given was excreted over the fledging period, and 49% of the dose was found in the plumage. These figures allow a more quantitative approach to measuring mercury pollution.
TL;DR: During gradient purification of herpes simplex virus type 1 (HSV-1) two bands of particles were observed: a sharp lower band and a more diffuse upper band which consisted of membrane-enclosed particles (L particles), which resembled the virions in appearance, but lacked the viral nucleocapsid and were not infectious.
Abstract: During gradient purification of herpes simplex virus type 1 (HSV-1) two bands of particles were observed: a sharp lower band and a more diffuse upper band. The lower band contained almost exclusively HSV-1 virions (H particles) whereas the upper band consisted of membrane-enclosed particles (L particles). These L particles resembled the virions in appearance, but lacked the viral nucleocapsid and were not infectious. Many polypeptides of the viral envelope and the tegument were common to both types of particles. The H particles had polypeptide profiles typical of HSV virions. The L particles contained at least three phosphoproteins (175K, 92K and 55K) and a further two phosphorylated polypeptides not normally observed in virion profiles which comigrated with the 134K and 60K glycoproteins. This clearly indicates that the novel L particles were not merely virions which had formed without the inclusion of a nucleocapsid or virions which had subsequently lost their nucleocapsid during preparative handling. Thus these novel L particles are genuine products of the infectious processes occurring when HSV-1 replicates.
26 Aug 1991
TL;DR: The code compiled from a non-strict functional program usually manipulates heap-allocated boxed numbers and optimises operations on boxed numbers into simpler operations on their unboxed forms.
Abstract: The code compiled from a non-strict functional program usually manipulates heap-allocated boxed numbers. Compilers for such languages often go to considerable trouble to optimise operations on boxed numbers into simpler operations on their unboxed forms. These optimisations are usually handled in an ad hoc manner in the code generator, because earlier phases of the compiler have no way to talk about unboxed values.
TL;DR: A model is suggested in which corals draw upon their extensive lipid stores on days of sub-optimal light, replenishing the reserves again when daily light levels are high, and finally excreting the excess energy fixed, as mucus-lipid when the lipid stores are replete.
Abstract: Energy budgets were determined for small pieces (nubbins) of the coralsPocillopora damicornis, Montipora verrucosa andPorites lobata living at a water depth of 3 m on the fringing reef of Coconut Island, Kaneohe, Hawaii. The budgets were determined for three different types of day: an “ideal” day with no cloud and an in situ daily integrated irradiance at 3 m of 14.385 E m−2 d−1; a “normal” day with sporadic cloud cover and daily irradiance of 11.915 E m−2 d−1; and an “overcast” day with daily irradiance of 6.128 E m−2 d−1. On the “ideal” day, the energy fixed in photosynthesis was more than that required for respiration and growth of both zooxanthellae and animal components of the association, and there was a predicted loss of between 19.3 and 32.4% of the energy fixed. On a “normal” day, the total photosynthetic energy fixation was lower and the excess was between 12.1 and 27.9% of the energy fixed. On the “overcast” day, however, in bothPocillopora damicornis andPorites lobata energy expenditure exceeded photosynthetic energy fixation and the budget was in deficit. Estimates of rate of mucus secretion on an “overcast” day were derived and, when incorporated into the energy budget, it was predicted that all three species would have a deficit budget, necessitating the catabolism of lipid reserves. From published values for lipid storage in these species it was calculated that the reserves would last from 28 d inPocillopora damicornis to 114 d inM. verrucosa. A model is suggested in which corals draw upon their extensive lipid stores on days of sub-optimal light, replenishing the reserves again when daily light levels are high, and finally excreting the excess energy fixed, as mucus-lipid when the lipid stores are replete.
TL;DR: Changes in the age structure of the breeding population and the absence in 1989 of 28% of adults colour-ringed during incubation in 1988 suggest an increase in the rate of egress since the 1970s, which probably represents an increased in the long-term costs of reproduction to adults at this colony.
Abstract: Great skuas on Foula, Shetland have responded to a decline in the availability of sandeels since the late 1970s by increasing the proportion of other items in their diets. This change is correlated with the annual recruitment of sandeels in Shetland waters. Since 1983 there has been a 10-fold increase in predation by great skuas upon other seabirds, as Furness & Hislop (1981) suggested might occur in response to a low availability of sandeels. Changes in diet have been accompanied by a 50% reduction in adult territorial attendance as adults increased their foraging effort, such that between 1987 and 1989 breeding adults were probably working as hard as they were able to. Despite this, breeding success was less than 40% in 1987 and less than 15% in 1988 and 1989. The major cause of breeding failure was predation of unguarded chicks by adults from neighbouring territories. The willingness of adults to expose their chicks to high predation risk is probably maintained because of a positive correlation between chick pre-fledging growth and post-fledging survival, which is expressed up to the age of two years and which will place a strong pressure upon adults to feed their chicks as well as possible. The high expenditure of effort by adults in 1987 and 1988 did not affect the weights of those birds incubating eggs in 1988 and 1989, but there was a slight (3%) decrease in egg size between the late 1970s and the late 1980s. Changes in the age structure of the breeding population and the absence in 1989 of 28% of adults colour-ringed during incubation in 1988 suggest an increase in the rate of egress since the 1970s. These changes probably represent an increase in the long-term costs of reproduction to adults at this colony.
TL;DR: The results support the hypothesis that Hodgkin's disease in different age groups may have different aetiologies, and suggest that EBV does have a pathogenetic role in Hodgkin’s disease in children and older age groups.
Abstract: An investigation as to whether any particular subgroup of patients with Hodgkin's disease was particularly likely to be Epstein-Barr virus (EBV) genome positive was made on samples from 95 patients. These were grouped according to age and Hodgkin's disease subtype, and analysed using Southern blot analysis. Most samples from children or adults aged 50 years or over contained detectable EBV genomes; samples from young adults were only rarely positive. The differences in EBV positivity by age were highly significant, but there was no significant association between EBV and histological subtype after allowing for the effect of age. The results support the hypothesis that Hodgkin's disease in different age groups may have different aetiologies, and suggest that EBV does have a pathogenetic role in Hodgkin's disease in children and older age groups.
Journal Article•
TL;DR: It is demonstrated that XerC also has a role in the segregation of replicated chromosomes at cell division, suggesting that the role of XerC/dif in chromosomal metabolism is to convert any chromosomal multimers (arising through homologous recombination) to monomers.
Abstract: XerC is a site-specific recombinase of the bacteriophage lambda integrase family that is encoded by xerC at 3700 kbp on the genetic map of Escherichia coli. The protein was originally identified through its role in converting multimers of plasmid ColE1 to monomers; only monomers are stably inherited. Here we demonstrate that XerC also has a role in the segregation of replicated chromosomes at cell division. xerC mutants form filaments with aberrant nucleotides that appear unable to partition correctly. A DNA segment (dif) from the replication terminus region of the E. coli chromosome binds XerC and acts as a substrate for XerC-mediated site-specific recombination when inserted into multicopy plasmids. This dif segment contains a region of 28 bp with sequence similarity to the crossover region of ColE1 cer. The cell division phenotype of xerC mutants is suppressed in strains deficient in homologous recombination, suggesting that the role of XerC/dif in chromosomal metabolism is to convert any chromosomal multimers (arising through homologous recombination) to monomers.
TL;DR: Persistent enteroviral infection of muscle may occur in some patients with postviral fatigue syndrome and may have an aetiological role.
Abstract: OBJECTIVE--To determine the presence of enteroviral sequences in muscle of patients with the postviral fatigue syndrome. DESIGN--Detection of sequences with the polymerase chain reaction in a well defined group of patients with the syndrome and controls over the same period. SETTING--Institute of Neurological Sciences, Glasgow. SUBJECTS--60 consecutive patients admitted to the institute with the postviral fatigue syndrome who had undergone extensive investigation to exclude other conditions. 41 controls from the same catchment area without evidence of fatigue, all undergoing routine surgery. MAIN OUTCOME MEASURES--Routine investigations, serological screen for antibodies to a range of viruses, and presence of enteroviral RNA sequences in muscle biopsy specimens. RESULTS--15 (25%) patients and 10 (24.4%) controls had important serological findings. 12 patients had neutralising antibody titres of greater than or equal to 256 to coxsackieviruses B1-5 (six positive for enteroviral RNA sequences, six negative); three were positive for Epstein-Barr virus specific IgM (two positive, one negative). Six controls had similar neutralising antibody titres to coxsackieviruses (all negative); one was positive for Epstein-Barr virus specific IgM (negative); and three had titres of complement fixing antibody greater than or equal to 256 to cytomegalovirus (all negative). Overall, significantly more patients than controls had enteroviral RNA sequences in muscle (32/60, 53% v 6/41, 15%; odds ratio 6.7, 95% confidence interval 2.4 to 18.2). This was not correlated with duration of disease, patient and age, or to raised titres of antibodies to coxsackieviruses B1-5. CONCLUSIONS--Persistent enteroviral infection of muscle may occur in some patients with postviral fatigue syndrome and may have an aetiological role.
01 Mar 1991-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: In this article, the authors describe the design and initial field testing of a photon tagging spectrometer which has been installed on the 840 MeV electron microton at the Institut fur Kernphysik in Mainz.
Abstract: This paper describes the design and initial field testing of a photon tagging spectrometer which has been installed on the 840 MeV electron microton at the Institut fur Kernphysik in Mainz. The spectrometer, which will enable bremsstrahlung produced photons in the energy range 40–790 MeV to be tagged, forms part of a proposed real photon beam facility for carrying out experiments on photonuclear reactions at intermediate energies.
TL;DR: Downstream of the HSV-2 immediate early gene, the RL sequence encoding the latency-associated transcripts (LATs) was found to be dissimilar to that in HSv-1; the probable LAT promoter regions, however, showed similarities toHSV-1.
Abstract: We report the determination of the DNA sequence of the long repeat (RL) region and adjacent parts of the long unique (UL) region in the genome of herpes simplex virus type 2 (HSV-2) strain HG52. The DNA sequences and genetic content of the extremities of HSV-2 UL were found to be closely similar to those determined previously for HSV-1. The 5658 bp sequenced at the left end of HSV-2 UL contained coding regions for genes UL1 to UL4 plus part of UL5. The 4355 bp sequenced at the right end of UL contained coding regions for part of gene UL53, and the whole of genes UL54 to UL56. Comparison of the HSV-1 and HSV-2 UL56 sequences led to a correction in the published HSV-1 UL56 reading frame. The HSV-2 RL region, including one copy of the a sequence, was determined to be 9263 bp, with a base composition of 75.4% G+C and with many repetitive sequence elements. In HSV-2 RL, sequences were identified corresponding to HSV-1 genes encoding the immediate early IE110 (ICP0) transcriptional regulator and the ICP34.5 neurovirulence factor; the former HSV-2 gene was proposed to contain two introns, and the latter one intron. Downstream of the HSV-2 immediate early gene, the RL sequence encoding the latency-associated transcripts (LATs) was found to be dissimilar to that in HSV-1; the probable LAT promoter regions, however, showed similarities to HSV-1. Properties of the LAT sequences in both HSV-1 and HSV-2 were consistent with LATs being generated as an intron excised from a longer transcript.
TL;DR: In this paper, it is shown that the shift depends only on dispersion interactions in non-polar solvents and that in polar media there is just a small extra contribution to the red-shift due to other forms of interactions.
Abstract: –Solvent induced absorption spectral shifts of the electronic transition from ground 1 Ag state to the excited 1Bu state in carotenoids have been studied. It is shown that the shift depends only on dispersion interactions in non-polar solvents. In polar media there is just a small extra contribution to the red-shift, due to other forms of interactions. The spectral shifts are well described by the theory, which expresses the shift relative to the gas phase value, as a function of solvent polarizability. The main conclusion is that the dominating mechanism behind the large red-shifted absorbance of carotenoids in the proteinacous environment, in vivo, is the mutual polarizability interactions between the carotenoids and the surrounding medium. The solution-phase values of the dipole moments of the lAg to 1Bu transitions and the differences of isotropic polarizability between 1Bu and lAg states of carotenoids in non-polar solvents are calculated and found to be around 13 D and 360 A3 respectively. From the great overlap of absorption spectra between carotenoids in quinoline and carotenoids in vivo in purple bacterial antenna complexes, it can be expected that the carotenoids are surrounded by several aromatic amino acids in vivo. Comparisons have been done between the exicted states in carotenoids and in linear conjugated polyenes.
TL;DR: Women with melanoma should be advised about pregnancy on the basis of thickness and site of tumour and evidence of vascular spread, and not hormonal status.
TL;DR: This chapter presents an overview of the unifying features as well as the diversity within the family Bunyaviridae, and orientates the reader for the more detailed analyses of individual virus groups which follow.
Abstract: More than 300 viruses are included in the family Bunyaviridae and hence show a number of unifying characteristics. However, with such a large number of members it is perhaps not unexpected that within the family there is significant diversity in genome structures and expression strategies. In this chapter we first present an overview of the unifying features as well as the diversity within the family. This will orientate the reader for the more detailed analyses of individual virus groups which follow.