Showing papers by "Swinburne University of Technology published in 1993"

Identification of conserved T cell receptor CDR3 residues contacting known exposed peptide side chains from a major histocompatibility complex class I‐bound determinant

Abstract: We have analyzed the T cell receptor (TCR) repertoire found in the major histocompatibility complex class I-restricted cytotoxic T lymphocyte (CTL) response to the protein ovalbumin (OVA). Despite skewing towards the expression of V beta 5.2+TCR by OVA-specific CTL from C57BL/6 mice, we found a relatively high degree of diversity in V(D)J usage in both TCR alpha- and beta-chains. Closer examination showed that the majority of these sequences encoded negatively and positively charged residues at their respective TCR alpha- and beta-chain VJ or VDJ junctions. These junctions form the third complementarity-determining regions (CDR3) of the TCR polypeptides involved in the direct interaction with the class I-bound peptide. Crystallographic analyses of Kb-peptide complexes predict that the major determinant from OVA, peptide OVA257-264 (SIINFEKL), contains two exposed charged side chains which can contact the TCR. These are the negatively charged glutamic acid at determinant position 6 (P6) and the positively charged lysine at P7. To examine whether the TCR alpha-chain makes contact with P7 lysine, we established a single chain TCR transgenic C57BL/6 mouse line where all T cells express a TCR beta-chain derived from the V beta 5.2+ clone B3. OVA-specific T cells derived from in vivo primed transgenic mice preferentially expressed TCR alpha-chains that also contained negatively charged junctional residues despite some further variation in V alpha and J alpha sequences. Stimulation of naive TCR beta-chain transgenic T cells with a P7 substitution peptide analogue induced a T cell response that was no longer cross-reactive with the wild-type OVA257-264 determinant, suggesting that the TCR alpha-chain from the T cell clone B3 can determine the specificity for this residue. Consequently, these results reveal the existence of conserved residues in the CDR3 of TCR alpha- and beta-chains specific for OVA257-264 and identify their possible orientation over the peptide-class I complex.

Decolourisation of a pigment plant effluent by Pycnoporus cinnabarinus in a packed-bed bioreactor

Abstract: The decolourisation of wastewater from a pigment plant by the white-rot fungus Pycnoporus cinnabarinus was studied in a packed-bed bioreactor. Decolourisation was first observed 48 to 72 h after inoculation and was followed using UV/VIS spectrophotometry. An assessment of the inhibitory properties of the effluent on the growth of Pycnoporus cinnabarinus showed that this fungus can tolerate high levels of potentially toxic waste.

Synthetic Peptide Analogs of Intercellular Adhesion Molecule 1 (ICAM-1) Inhibit HIV-1 Replication in MT-2 Cells

Abstract: On the basis of reports demonstrating possible roles for leukocyte function-associated antigen 1 (LFA-1) and intercellular adhesion molecule 1 (ICAM-1), the ligand for LFA-1, in human immunodeficiency virus type 1 (HIV-1) infection, we have explored the involvement of the ICAM-1 molecule by using selected synthetic peptides derived from the protein sequence. Replication was assessed in MT-2 cells, highly susceptible to HIV infection, in the presence of four synthetic peptides derived from the ICAM-1 amino acid sequence. This cell type was chosen for the ability to form marked syncytia on infection with cell-free virus. Under the conditions used, minimal or no cytotoxicity was observed with the peptides up to concentrations of 50 micrograms/ml. A peptide corresponding to a unique region of ICAM-1, JF9 [ICAM-1(367-394, A-378)], had little effect on virus replication despite its ability to inhibit cell-cell adhesion. In contrast, an N-terminal peptide, JF7B [ICAM-1(1-23)], consistently inhibited virus replication in MT-2 cells in a dose-dependent manner, as measured by cell-free reverse transcriptase (RT) activity (up to 70% inhibition), soluble virus antigen production (up to 60% inhibition), and syncytium formation (virtually complete inhibition up to 6 days post infection). Testing of W-CAM-1 antibody, and anti-ICAM-1 antibody that inhibits cell-cell adhesion, revealed no significant inhibitory effects on RT activity, virus antigen production, and syncytium formation in HIV-1-infected MT-2 cells at a level that markedly inhibited cell-cell adhesion (10 micrograms/ml).(ABSTRACT TRUNCATED AT 250 WORDS)

Computer Forecasting of Australian Rules Football for a Daily Newspaper

Abstract: The major winter sport of the southern states of Australia is Australian Rules Football, played between teams of 18 players on oval grounds (the same grounds used for cricket during the summer). A match is played for four quarters, each of 25 minutes duration plus about 5 minutes of extra time. Players can run with the rugby-shaped ball, but it is moved forward more quickly by kicking or punching it to a team-mate, and with no off-side rule, the game is reasonably fast. The scoring region consists of four upright posts. Kicking the ball between the two centre posts scores a goal worth 6 points, while the region between either centre post and the corresponding outside post scores a ‘behind’ worth 1 point. Draws are rare; a typical score might be 18 goals 12 behinds, 120 points, to 12 goals 15 behinds, 87 points, for a winning margin of 33 points. In 1981 the major competition in Australia was organized by the Victorian Football League (VFL), in which 12 Melbourne based clubs played for 22 home and away rounds with a final series of six matches between the top five teams.

Capillary electrophoresis separation of sulphonamides and dihydrofolate reductase inhibitors

Abstract: Twenty-two sulphonamides and three dihydrofolate reductase inhibitors (DHFR) were included in this study. At pH 7.5, eighteen drugs were resolved in 22 min. Above pH 7.5 the DHFR are not resolved and the pH range of 7-7.5 was found to be optimal. Around pH 7, where the degree of ionization of the SFA is highly variable, pKa and migration time are strongly correlated. Increasing phosphate buffer concentration from 25-100 mM generally improves resolution but increases analysis times. A good correlation between analyte mobility and the ratio of net charge to molecular weight indicates that this ratio may be used as a quick guide to the possibility of separation of related compounds. Our secondary objective was to compare the lead time and effectiveness of CZE with LC. It is clear that method development is much more rapid in CZE but with a sufficiently diverse group of compounds, CZE can be incapable of providing a full analysis without gradient control. Nonionized compounds are not separated at one extreme, and excessively mobile species may not emerge in a reasonable time, or, may migrate to the wrong electrode.

The Supercritical Fluid Extraction of Polar Drugs (Sulphonamides) from Inert Matrices and Meat Animal Products

Abstract: The objective of this study was to examine the extension of supercritical fluid extraction (SFE) to the extraction of polar drugs. The ultimate aim was to extract veterinary residues from food animal products and thereby demonstrate the versatility of SFE. This technique is shown to have many facets that require careful thought and understanding if it is to be successfully used. Our initial studies indicate that polar drugs may be readily solubilized from relatively inert matrices such as sand, with high recoveries and very little discrimination between related compounds while using only moderate extraction conditions and times. SFE of the same drugs from spiked chicken liver and swine muscle is significantly more difficult and requires more drastic conditions. Close to complete recoveries are achieved for some drugs, while considerably less is found in the worst case. For sulphamerazine, sulphamethizole, sulphamethazine, sulphamethoxypyridazine, sulphamethoxazole, and the major metabolite N4-acetyl-sulphamethoxazole, the recoveries are 97, 66, 94, 79, 53, and 65%, respectively, from spiked liver and 95, 27, 86, 91, 96 and 70%, respectively, from spiked swine muscle. Incurred sulphamethazine is recovered from swine muscle in good general agreement with the reference values provided.

Rheology of low viscosity, high concentration brown coal suspensions

Abstract: The paper describes how the theology of low concentration brown coal suspensions can be exploited to produce high concentration, low viscosity suspensions which are attractive as a potential coal-water fuel. Brown coal suspensions with solid concentrations approaching those of bituminous black coal have been prepared. The high inherent water content (≈ 60 wt %) and macroporosity of the brown coal have been reduced by thermal and chemical means. The hydrophobicity of the coal surface has been increased sufficiently to reduce the tendency for swelling and water uptake. This, together with densification, has allowed the solids content to be progressively improved from 30 wt % solids with raw coal to 65 wt% solids with modified coals while maintaining the viscosity of the suspension at a low level. The high solid concentration was achieved without additives.

Comparison of high resolution EEG methods having different theoretical bases

Abstract: Mathematically simulated data is used to obtain direct comparisons of the accuracies of spline/Laplacian and cortical imaging algorithms in predicting cortical potential. Even though the two approaches have quite different theoretical bases, the two methods provide nearly identical estimates of cortical activity at scales greater than about 2 or 3 cm when 64 electrodes are used.

Death anxiety and death denial: Nigerian and Australian students' metaphors of personal death.

Abstract: Ninety-two Nigerian students and 114 Australian students completed Tempter's (1970) Death Anxiety Scale (DAS) and Feifel and Nagy's (1981) death fantasy measure of positive and negative death metaphors. They were each also asked to write his or her own metaphor of personal death. Results of the DAS showed that the two groups did not differ significantly on the level of conscious death anxiety, but Nigerian students' scores were significantly higher on both positive and negative personal death metaphors scales. Also, significantly more Nigerian students wrote personal metaphors of their own and more often used a neutral metaphor to describe their personal death. Australian students more often used a positive or a negative metaphor. The Nigerian students thus evidenced less death denial than the Australian students did.

Mycelial fragment size distribution: an analysis based on fractal geometry

Abstract: The use of white-rot fungi for biodegradative research and developmental application requires seeding with a suitable inoculum. This paper presents a new method for the quantitative analysis of a mycelial inoculum composed of homogenized hyphal fragments. Our method is premised on a power-law behaviour between frequency and the size of these mycelial fragments. It is shown that the fragment distribution profile can be determined by regression to give the fractal fragmentation dimension, D. The influence of homogenizer speed was also investigated over a range from 8333 rpm to 25 000 rpm, which corresponds to a shear rate range of 13.9 × 103 to 41.7 × 103 s−1. The highest D value was shown at a shear rate of 27.8 × 103 s−1 for 30 s, implying greatest homogeneity in the size distribution function over the measured range (0–500 μm2). As shear force and duration increases (up to a threshold value) the production of small fragments is facilitated with a corresponding decrease in the D value. The slope relation express the fragment diversity whereas the reciprocal fractal valie characterizes the distribution size probability. Image-analysis methodology is described and the implications of a fractal description of a mycelial inoculum are also considered.

Possible health effects of 50/60Hz electric and magnetic fields: review of proposed mechanisms.

Abstract: There is inconclusive evidence from both epidemiological and laboratory studies that fields similar to those produced by electrical power transmission lines may contribute to certain diseases including cancer. There are several objections to a hypothesis of a direct causative link, based on identifying a mechanism of interaction. One is that the energy density of the fields is several orders of magnitude smaller than that associated with random thermal motion in biological tissue. Secondly, the induced currents are many times smaller than endogenous currents associated with normal membrane processes. A comparison of current densities and characteristics associated with field-related phenomena such as electrosensitivity in species of fish, night-time melatonin depression in rodents, limb regeneration in amphibians and magnetophosphenes in humans reveals little that can be of use in determining a 'response metric', yet guide-lines for the general public are in fact based on this quantity, for immediate effects at least. Indeed, currents induced by the electric component of environmental 50 Hz fields are of similar magnitude to those induced by the magnetic component, yet epidemiological studies have identified surrogates of the latter as the significant exposure metric in relation to cancer incidence. Proposed mechanisms, many of which are still at the 'working hypothesis' stage, are compared with experimental evidence. Some conflict with epidemiological evidence, itself not strong, but becoming stronger, is apparent.

Introducing Undergraduates to the Spirit of OR whilst Imparting Substantive Skills

Abstract: This paper presents an outline of two introductory undergraduate courses in OR which specifically aim to emphasize aspects of Operational Research (OR) other than just the mathematical tools involved. The courses were developed independently, but have many similarities and both address the same problem — how to present the broad and somewhat elusive nature of practical OR to undergraduate students encountering the subject for the first time. It is the authors' belief that, although difficult, this is both desirable and possible within the resource constraints which naturally apply to undergraduate level teaching. A basic understanding of the general nature and philosophy of OR at an early stage can do much to stimulate and motivate students to get the most out of their further studies, not only in OR, but also in statistics, computing, applied mathematics and related fields. Both of the courses described include elements such as special lectures, case studies, group working, report writing and management games — ideas which may be able to be adapted and improved to be of use in a variety of introductory OR courses.

E3: Towards the Metrication of Graphical Presentation Techniques for Large Data Sets

Abstract: Rapid advances in communications and computer technologies in recent years have provided users with greater access to large volumes of data from computer-based information systems. Whilst researchers have developed many novel techniques to overcome the problems associated with the presentation and navigation of large data sets on a limited display surface, the choice of a technique in a particular application remains very subjective. This paper proposes an evaluation framework E3 which aims to provide a basis for the comparison of different presentation techniques, given the nature and characteristics of the data to be presented, and the interpretation required. E3 focuses on three aspects of graphical data presentation: expressiveness, efficiency, and effectiveness. This framework lays the foundation for the development of a set of metrics to facilitate an objective assessment of presentation techniques.

The development of an integrated mathematical model of an aluminium smelter

Abstract: This paper outlines the development of an integrated mathematical model of an aluminium smelter incorporating the raw materials feed, carbon bake, rodding, potrooms and ingot mill areas, together with non-linear feedback loops. The model is structured to facilitate its use for planning and managing both technological and economic change.

Vulnerability to psychological distress: empirical and conceptual distinctions between measures of neuroticism and negative affect

Abstract: In two studies, 97 and 176 individuals (47 men and 50 women, M age 34.2 yr.; and 88 men and 88 women, M age 34.8) known to have experienced a recent period of psychological distress were compared with otherwise similar individuals who reported no such experience on measures of neuroticism, extraversion, and positive and negative affect. In both studies, the neuroticism measure was a significant independent discriminator between the groups while the negative affect measure was not. This suggests that (a) measures of neuroticism tap factors additional to those tapped by scales measuring only levels of characteristic negative affect and (b) these factors are related to individual differences in vulnerability to psychological distress.

Method of producing binderless pellets from low rank coal

Abstract: The invention relates to a method and apparatus of forming pellets and in particular spherical binderless pellets from lower rank coals. The method includes the steps of feeding a pelletizing means 10, with a lower rank feedstock, 1; rotating the coal in said pelletizing means, 10, to form pellets in the absence of any binder, wherein the pellets are formed by compaction and layering of coal fines. The moisture content of the lower rank coal is at a level so as to at least substantially fill the voids within the coal.

On the teletraffic characterization of cellular CDMA systems

Abstract: In code division multiple access (CDMA) cellular mobile communications systems, the teletraffic carrying capabilities and service quality depend on system parameters which can vary considerably with time and environment. In studying the variability in the teletraffic performance of CDMA systems, the authors employ a measure of service quality, called CDMA quality measure (CQM), a weighted sum of degradations due to blocking and speech impairments. Then, for a required CQM value, teletraffic capability is defined as that value of offered traffic for which the CQM value can be maintained. This teletraffic capability is a more meaningful measure of CDMA teletraffic performance than is the concept of capacity as used in frequency division multiple access (FDMA) and time division multiple access (TDMA) systems. The reverse (mobile to cell-site) path is simulated in non-uniform CDMA networks and teletraffic capability is evaluated for finite CDMA cellular networks to show how traffic capability is suitable for quantifying the performance variations under various operational conditions.

Therapist construct systems in use during psychotherapy interviews.

Abstract: An innovative psychotherapy process research methodology that combines Interpersonal Process Recall with Repertory Grid analysis is introduced. This methodology was employed to examine the construct systems used by a therapist to make client behaviors meaningful. The therapist's construct systems varied across the three interviews studied. In the interview during which the therapist was judged to be most effective, the construct system used evidenced a higher level of cognitive complexity than the construct systems used in the other two interviews. Research applications of the methodology are discussed.

Young Women's Career Choices A Longitudinal and Cross Sectional Study

Abstract: This study investigated the career choices of young women attending a single-sex church school using both longitudinal and cross-sectional data. Ninety-nine Year 12 students completed Holland's Self-directed Search (SDS) in 1985. In 1991, 40 of these respondents again completed the SDS and provided demographic and employment information. Also in 1991, the school's Year 12 students (n = 87) completed the SDS and provided demographic data. SDS scores for the longitudinal group (students retested in 1991) showed that their vocational preferences changed with Realistic, Artistic, Enterprising and Conventional scores increasing and Social scores remaining the same. Comparisons between the longitudinal group's 1985 and 1991 SDS scores and the type of course and employment they pursued lent support to developmental theories of career choice. Cross-sectional results indicated that there were very few differences in the vocational preferences of the 1985 and 1991 Year 12 students. Thus results also suggested that ...

The use of digital image segmentation to quantify an aminoanthraquinone dye biotransformation by white-rot fungi

Abstract: Three methods are presented for the objective, digital evaluation of Remazol Brilliant Blue R dye biotransformation by the white rot fungi, Pycnoporus cinnabarinus and Phanerochaete chrysosporium. This screening technique uses computerized image analysis and a binary logical and function to provide a rapid (2 min per analysis), quantitative, digital densitometry interpretation of enzyme induced chromophore conversion by fungi. A kinetic measure of metabolic activity (enzyme activity coefficient, μ) may also be determined. It is shown that chromophore conversion is more rapid and extensive by P. cinnabarinus.

Parent‐Child Agreement Regarding Nuclear Issues

Abstract: This study investigated the extent to which parents and their children (in two age groups) agree about nuclear war issues. Three dimensions of agreement—actual agreement, perceived agreement, and accuracy of perception—were examined with respect to parents' knowledge of their children's views. Parents' and children's responses to 18 nuclear-issues questions were factor analysed, producing five orthogonal factors: nuclear denial, nuclear awareness, political efficacy, belief in deterrence, and nuclear anxiety. Younger children showed significantly greater nuclear awareness (or concern), lower levels of denial, and higher levels of anxiety than their parents. Teenagers showed more concern about nuclear war than their parents and denied the threat to a lesser degree. Contrary to expectation, parents were more anxious about the threat than their teenage children and showed greater denial despite a comparable level of awareness. Parents accurately perceived their teenage children's responses for nucle...

The death fantasy scale: a measure based on metaphors of one's personal death

Abstract: Conventional self-report inventories measuring attitudes toward death have been criticized on the grounds that they fail to tap important unconscious processes related to death anxieties and are contaminated by broad personality dispositions such as neuroticism. In this study, using Australian volunteers as subjects, we investigated a measure devised by Feifel and Nagy (1981) to tap death-related attitudes at a fantasy level. The scale contained two subscales: Positive Death Metaphors and Negative Death Metaphors, both of which were internally consistent and relatively uncorrelated with a general measure of neuroticism. The measure shows potential as a tool for investigating aspects of attitudes toward death and dying.

Programming and Design

Abstract: An important component of programming is the process of design and this should be taken account of when developing cognitive models of the programming activity. Most empirical studies of programming neglect this dimension because of the absence of a theory, the difficulties associated with collecting and analysing empirical data and a commitment to the top-down philosophy of design. This paper reports work that has been carried out in modelling the conceptual design activity in both the software engineering and mechanical engineering domains. A novel method for analysing verbal protocols, based on functional discourse analysis is outlined and a blackboard based model of conceptual design is presented.

Systematic construction of design models from temporal logic based descriptions

Abstract: This paper presents an approach which allows one to synthesise manufacturing system design models from temporal logic based descriptions. The aim of the approach is to obtain a functional abstraction of the actual system. This functional abstraction realises the external functional behaviour of the modelled system without replicating the actual mechanism. It involves less places and transitions than the accurately modelled system, thus allowing to ease the verification task effort. The approach is illustrated when used to synthesise a machining station. A formal proof of the logical correctness of the obtained model is also presented. >

An application of neural networks to emulation of aesthetic judgements

Abstract: Models of perception of abstract black and white images are proposed. The core part of the models are artificial neural networks (ANNs). The computer system is trained by providing samples of pictures and some pre-calculated characteristics. Once successfully trained, the system is able to classify new pictures displaying aesthetic preferences similar to those owned by its teachers. >