Showing papers by "Dublin City University published in 1992"
TL;DR: In this article, an on-column joint utilizing Nafion tubing for the isolation of the electrical circuit from the detection end of a capillary zone electrophoresis system is described.
168 citations
TL;DR: This paper will examine and review recent progress in using the lexical, syntactic, semantic and discourse levels of the language analysis for tasks like automatic and semi-automatic indexing of text, text retrieval, text abstracting and summarisation, thesaurus generation from text corpus and conceptual information retrieval.
Abstract: Techniques of automatic natural language processing have been under development since the earliest computing machines, and in recent years these techniques have proven to be robust, reliable and efficient enough to lead to commercial products in many areas. The applications include machine translation, natural language interfaces and the stylistic analysis of texts but NLP techniques have also been applied to other computing tasks besides these. In this paper we will examine and review recent progress in using the lexical, syntactic, semantic and discourse levels of the language analysis for tasks like automatic and semi-automatic indexing of text, text retrieval, text abstracting and summarisation, thesaurus generation from text corpus and conceptual information retrieval. Our own work on the application of syntactic analysis to the matching and ranking of phrases using structured representations of texts, will be included in the overview. Finally, the prospects for gains in terms of overall retrieval effectiveness or quality will be discussed.
128 citations
TL;DR: Laboratory and brewing strains of Saccharomyces cerevisiae were compared for metabolism-independent and -dependent Sr2+ uptake, and a decline in cytoplasmic, and particularly vacuolar, Mg2+, in comparison with that of cells incubated with Sr 2+ in the absence of glucose was apparent.
Abstract: Laboratory and brewing strains of Saccharomyces cerevisiae were compared for metabolism-independent and -dependent Sr2+ uptake. Cell surface adsorption of Sr2+ to live cells was greater in the brewing than in the laboratory strain examined. However, uptake levels were greater in denatured (dried and ground) S. cerevisiae, and the relative affinities of Sr2+ for the two strains were reversed. Results for the brewing S. cerevisiae strain were similar whether the organism was obtained fresh from brewery waste or after culturing under the same conditions as for the laboratory strain. Reciprocal Langmuir plots of uptake data for live biomass were not linear, whereas those for denatured biomass were. The more complex Sr2+ binding mechanism inferred for live S. cerevisiae was underlined by cation displacement experiments. Sr2+ adsorption to live cells resulted in release of Mg2+, Ca2+, and H+, suggesting a combination of ionic and covalent bonding of Sr2+. In contrast, Mg2+ was the predominant exchangeable cation on denatured biomass, indicating primarily electrostatic attraction of Sr2+. Incubation of live S. cerevisiae in the presence of glucose resulted in a stimulation of Sr2+ uptake. Cell fractionation revealed that this increased Sr2+ uptake was mostly due to sequestration of Sr2+ in the vacuole, although a small increase in cytoplasmic Sr2+ was also evident. No stimulation or inhibition of active H+ efflux resulted from metabolism-dependent Sr2+ accumulation. However, a decline in cytoplasmic, and particularly vacuolar, Mg2+, in comparison with that of cells incubated with Sr2+ in the absence of glucose, was apparent. This was most marked for the laboratory S. cerevisiae strain, which contained higher Mg2+ levels than the brewing strain.
125 citations
TL;DR: An analytical treatment of the electron energy distribution function in a low pressure nitrogen rf discharge shows that contrary to the conventional model, the electrons are heated in part by retreating sheaths.
Abstract: We have determined the electron energy distribution function (EEDF) in a low pressure nitrogen rf discharge both experimentally and using a computer simulation. The EEDFs show unusual structures, which can be interpreted in terms of a sheath-oscillation electron heating mechanism. However, the simulation shows that contrary to the conventional model, the electrons are heated in part by retreating sheaths. We present an analytical treatment of this phenomenon.
109 citations
TL;DR: Capillary electrophoresis with electrochemical detection was used to determine extracellular levels of aspartate, glutamate and alanine in samples from the frontoparietal cortex of the rat which were obtained by microdialysis.
106 citations
TL;DR: A review of the excited-state acidity of inorganic compounds can be found in this paper, where the authors focus on the evaluation of excited state pK, values, and to a lesser extent on the kinetics of the protonation process of ruthenium polypyridyl complexes.
97 citations
TL;DR: Four lipophilic sulphur and/or nitrogen containing calixarene derivatives have been tested as ionophores in Ag(I)-selective poly (vinyl chloride) membrane electrodes, giving acceptable linear responses and high selectivity towards other transition metals and sodium and potassium ions.
78 citations
TL;DR: In this paper, nine different trial beers were produced on a pilot scale from a common feedstock by using, either singly or in combination, three dosage rates (0, 15, and 30 g/hl) of polyvinylpolypyrrolidone (PVP...
Abstract: Nine different trial beers were produced on a pilot scale from a common feedstock by using, either singly or in combination, three dosage rates (0, 15, and 30 g/hl) of polyvinylpolypyrrolidone (PVP...
69 citations
TL;DR: This paper presents a cytogenetic analysis of two established but early-passage cell lines derived from histologically similar, poorly differentiated lymph node metastases of squamous cell carcinoma of the lung, and indicates significant cytogenetics heterogeneity between these early- Passages 5 and 18.
53 citations
TL;DR: The results suggest that P. acidilactici G24 may be useful as a silage inoculant for crops with a sufficiently high water-soluble carbohydrate level.
Abstract: Eighteen Pediococcus strains were screened for their potential as silage inoculants. Pediococcus acidilactici G24 was found to be the most suitable, exhibiting a short lag phase on both glucose and fructose, a rapid rate of acid production, a high sugar-to-lactate conversion efficiency, no detectable breakdown of proteins or lactic acid, and the ability to grow within a broad range of pH and temperature. When tested in laboratory silos using grass with a water-soluble carbohydrate content of 24 g/kg of aqueous extract, P. acidilactici G24 stimulated the natural Lactobacillus plantarum population and accelerated the rates of lactic acid production and pH decrease. After 6 days of fermentation, the inoculated silage exhibited a 12% decrease in ammonia nitrogen and an 11% increase in crude protein levels compared with uninoculated controls. The use of an L. plantarum inoculant at a rate of 104 bacteria per g of grass in conjunction with P. acidilactici G24 produced no additional beneficial effect. Inoculation of grass with a water-soluble carbohydrate level of 8 g/kg of aqueous extract with P. acidilactici G24 led to no acceleration in the rate of L. plantarum growth or pH decrease. However, after 7 days of fermentation the inoculated silage had a 14% lower ammonia nitrogen protein content than did uninoculated controls. The results suggest that P. acidilactici G24 may be useful as a silage inoculant for crops with a sufficiently high water-soluble carbohydrate level.
51 citations
TL;DR: In this paper, the authors used capillary electrophoresis with electrochemical detection in the analysis of samples obtained during continuous monitoring of the pharmacokinetics of L-dopa in the rat.
Abstract: Electrochemical detection has been shown to be a sensitive method of detection in capillary electrophoresis (CE). The small sample volume required for CE makes it ideal for the analysis of microdialysis samples. In this paper, capillary electrophoresis with electrochemical detection is utilized in the analysis of samples obtained during continuous monitoring of the pharmacokinetics of L-dopa in the rat. The detection limit for L-dopa was 98 attomoles or 3.9 ng/mL. The elimination half-life was calculated to be 10.3 ± 1.1 minutes. Voltammetric characterization was used to verify the identity of L-dopa and its metabolites. The effects of electrochemical pretreatment on the detector performance was also investigated.
TL;DR: A rapid and sensitive high-performance liquid chromatographic method was developed for the analysis of coumarin, 7-hydroxycoumarin and its glucuronide conjugate in urine and plasma and includes an internal standard.
TL;DR: A 300-fold adriamycin resistant variant (DLKP-A) of the human lung squamous cell carcinoma line DLKP was established by stepwise selection in increasing concentrations of adRIamycin by establishing a direct causal role for P-glycoprotein overexpression in the resistant phenotype by transfection with an mdr1 specific antisense oligonucleotide.
Abstract: A 300-fold adriamycin resistant variant (DLKP-A) of the human lung squamous cell carcinoma line DLKP was established by stepwise selection in increasing concentrations of adriamycin. Different levels of cross-resistance were observed towards VP-16, VM-26, colchicine, vincristine and, somewhat unexpectedly, cis-platin. Resistance was stable for at least 3 months in culture in the absence of drug. P-glycoprotein overexpression was detected by immunofluorescence and Western Blotting, and a direct causal role for P-glycoprotein overexpression in the resistant phenotype was established by transfection with an mdr1 specific antisense oligonucleotide. A modified cryopreservation procedure was necessary for the resistant variant line. The resistant population displays clonal heterogeneity with respect to resistance level. A higher frequency of double minute chromosomes was observed in DLKP-A when compared with the parental cell line.
TL;DR: By expressing the error term in truncation of the asymptotic expansion in terms of a Mellin-Barnes integral, this paper obtained an exponentially improved version of Dingle's result for Γ(z) as ∣z ∣ → ∞ in ∣ arg z ∣ < π.
TL;DR: This paper describes a process whereby a morpho-syntactic analysis of phrases or user queries is used to generate a structured representation of text to evaluate the effectiveness or quality of the matching and scoring of phrases.
Abstract: The application of automatic natural language processing techniques to the indexing and the retrieval of text information has been a target of information retrieval researchers for some time. Incorporating semantic-level processing of language into retrieval has led to conceptual information retrieval, which is effective but usually restricted in its domain. Using syntactic-level analysis is domain-independent, but has not yet yielded significant improvements in retrieval quality. This paper describes a process whereby a morpho-syntactic analysis of phrases or user queries is used to generate a structured representation of text. A process of matching these structured representations is then described that generates a metric value or score indicating the degree of match between phrases. This scoring can then be used for ranking the phrases. In order to evaluate the effectiveness or quality of the matching and scoring of phrases, some experiments are described that indicate the method to be quite useful. Ultimately the phrasematching technique described here would be used as part of an overall document retrieval strategy, and some future work towards this direction is outlined.
TL;DR: In this article, the effect of electrolyte concentration and redox site loading on the homogeneous charge transport rate was examined in both sodium chloride and lithium perchlorate supporting electrolytes.
TL;DR: The Henon discrete mapping, the Lorenz system of coupled ordinary differential equations, and the Mackey-Glass infinite-dimensional delay differential equation have been used as paradigms for the study of chaos as mentioned in this paper.
Abstract: We give a brief introduction to chaos and its characterization. We examine some standard systems in detail from the perspective of chaos and review their properties. Concepts necessary to understand them, such as dimension, are also reviewed. To illustrate the main ideas, we choose three examples which have served as paradigms for the study of chaos in physical systems, namely, the Henon discrete mapping, the Lorenz system of coupled ordinary differential equations, and the Mackey-Glass infinite-dimensional delay differential equation.
TL;DR: The results demonstrate that both rodent malaria species show an in vitro preference for reticulocytes although the preference of P.c. c.
Abstract: Erythrocyte invasion assays are described for two species of rodent malaria, namely Plasmodium berghei and P.c. chabaudi. These invasion assays are simple, are carried out using a candle jar and allow a number of assays to be performed simultaneously. Our results demonstrate that both rodent malaria species show an in vitro preference for reticulocytes although the preference of P. c. chabaudi for these cells is not as marked as that of P. berghei. The details of our invasion assays and our results obtained are discussed.
TL;DR: A simple, rapid and sensitive voltammetric method was developed for the determination of the drug in a tablet dosage form based on the study of the oxidation of sumatriptan succinate at the glassy carbon electrode.
TL;DR: The fast response permits adaptation for flow injection operation with good precision and high sample throughout and the high specificity offered by this new enzyme is indicated by the lack of interference by other L-amino acids, alcohols or carbohydrates.
TL;DR: Flow-injection studies indicated the suitability of this electrode as a detector in flowing streams and the modified electrode response was shown to be relatively stable over a period of 5 days with a signal diminution of 8%.
TL;DR: In this article, the anodic stripping voltammetry of selenium (IV) in a gold fiber electrochemical flow cell is described, which results in a linear working range from 0-15 ng/mL, a detection limit of 0.5 n/mL Se(IV) and a relative standard deviation of 6% at 5 ng /mL (n = 7) in pure solution.
Abstract: The anodic stripping voltammetry of selenium (IV) in a gold fiber electrochemical flow cell is described. The cell is simple to construct and flexible in its operation. The nonlinear diffusional mass transport characteristics of such small diameter electrodes influence the anodic stripping voltammetry of Se(IV) with the result that significant deposition of metal ions occurs during the scan period from the deposition potential to the peak potential. Therefore, an extremely short deposition period of the order of 20 seconds can be employed at the gold fiber electrode. The system described resulted in a linear working range from 0–15 ng/mL, a detection limit of 0.5 ng/mL Se(IV) and a relative standard deviation of 6% at 5 ng/mL (n = 7) in pure solution.
TL;DR: In this paper, a review of the preparation and properties of cubic boron nitride thin films is presented and emphasis is placed on the relationship between properties, especially hardness and microstructures.
TL;DR: Optical fluorescence and decay times of Eu3+-doped silica sol-gel glasses were measured as a function of processing parameters such as densification temperature, pH and water:precursor ratio.
Abstract: Optical fluorescence and decay times of Eu3+-doped silica sol-gel glasses were measured as a function of processing parameters such as densification temperature, pH and water:precursor ratio. The optical data were interpreted in terms of structural changes in the Eu3+ environment under different sol-gel processing conditions.
TL;DR: A high-performance liquid chromatographic method is described for the determination of terbutaline in human plasma in the range 1-35 ng/ml, providing a method which was sensitive and reproducible, where the mean overall coefficient of variation was 5.60% and drug recovery in excess of 86% at the concentration levels studied.
Abstract: A high-performance liquid chromatographic (HPLC) method for the determination of salbutamol in human plasma is described based on separation on a reversed-phase C18 column followed by detection using a carbon fiber-based electrochemical detector. The carbon fiber-based flow electrode used in the analytical system showed some advantages over conventional electrochemical detectors using glassy carbon electrodes. It is easy to prepare, flexible to operate, and suffers less trouble from air bubbles and leaks. It was shown that this kind of microelectrode flow detector exhibits a better detection limit (1 ngml−1) to that obtained using a conventional glassy carbon electrode flow detector (3 ngml−1). The method was found to be reproducible, with a mean overall coefficient of variation (C.V.) of 5.4%, and drug recovery was in excess of 85% at the concentration levels studied.
TL;DR: A series of ruthenium polypyridyl complexes has been covalently bound to poly(L-lysine), bovine serum albumin, human serumalbumin, ovalbumin, and immunoglobulin G using different binding methods and all conjugates show nonsingle-exponential decay curves.
TL;DR: In this article, the application of carbon paste electrodes (constructed using silicone oil) in solutions containing 50% methanol (v/v) is demonstrated, and the silicone oil-carbon paste electrode has been shown to be a useful working electrode in methanolic media to investigate the voltammetric behavior of some native and nitrated phenothiazine derivatives.
TL;DR: In this paper, a range of PVD thin films are evaluated from both Magnetron Sputtered and Arc Evaporated systems and the most suitable candidate coatings are identified for potential applications in the surface engineering of multipoint cutting tools.
TL;DR: The reaction between mercury(II) and the tetraphenylborate ion results in the formation of diphenylmercury, thus providing the method with good selectivity over other metal ions.