Selective determination of amino acids using flow injection analysis coupled with chemiluminescence detection

The determination of the amino acids proline, histidine, tyrosine, arginine, phenylalanine and tryptophan using flow injection analysis (FIA) with chemiluminescence detection is described. Proline was the only amino acid to exhibit chemiluminescence with the tris(2,2-bipyridyl)ruthenium(III) reaction at pH 10. While, histidine was found to selectively enhance the reaction of luminol with Mn(II) salts in a basic medium. Acidic potassium permanganate chemiluminescence was able to selectively determine tyrosine at pH 6.75. Low pressure separations using a C18 guard column allowed the simultaneous determination of tyrosine and tryptophan or phenylalanine and tryptophan with acidic potassium permanganate and copper(II)–amino acid–hydrogen peroxide chemiluminescence, respectively. Precision for each method was less than 3.9% (R.S.D.) for five replicates of a standard (1×10−5 M) and the detection limits ranged between 4×10−9 and 7×10−6 M. Preliminary investigations revealed that the methodology developed was able to selectively determine the individual amino acids in an equimolar mixture of the 20 naturally occurring amino acids.

Comparative analysis of two selective bleaching methods on alpaca fibers

Dark brown Alpaca fiber was reduced in shade via selective bleaching with peroxide. Two selective oxidative bleaching methods were tested on alpaca top to assess their effectiveness for color removal and fiber quality properties. Color change, bundle strength, weight loss, fiber diameter, surface modification, dye-ability and dye wash fastness were assessed for both methods and compared with the original brown top. Bleach method 1 (BL-I) showed little surface modification, 5.8 % weight loss and 2.4 % strength loss. D1925 yellowness index was reduced to 74.3 from 83.1 and provided a good base for the dyeing of medium to deep shades. Bleach method 2 (BL-II) displayed considerable surface modification, 7.8 % weight loss and 18 % strength loss. BL-II also resulted in a mean diameter reduction of 1.9 micron during bleaching. Yellow-ness was reduced to 64.5 from 83.1 and provided a very good base for the dyeing of medium to deep shades. BL-I showed better exhaustion of the pre-metallised dye Lanaset Violet B than BL-II. Wash fastness for BL-II was 1 grey scale unit poorer than BL-I. BL-II showed far better color clarity at pale depths however the wash fastness of the finished product was not good enough to maintain the depth or clarity of the color. BL-I showed poorer clarity of color but exhibited better wash fastness results.

The assessment of тт-тт selective stationary phases for two-dimensional HPLC analysis of foods : application to the analysis of coffee

Differences between alkyl, dipole–dipole, hydrogen bonding, and π-π selective surfaces represented by non-resonance and resonance π-stationary phases have been assessed for the separation of ‘Ristretto’ café espresso by employing 2DHPLC techniques with C18 phase selectivity detection. Geometric approach to factor analysis (GAFA) was used to measure the detected peaks (N), spreading angle (β), correlation, practical peak capacity (n_p) and percentage usage of the separations space, as an assessment of selectivity differences between regional quadrants of the two-dimensional separation plane. Although all tested systems were correlated to some degree to the C18 dimension, regional measurement of separation divergence revealed that performance of specific systems was better for certain sample components. The results illustrate that because of the complexity of the ‘real’ sample obtaining a truly orthogonal two-dimensional system for complex samples of natural origin may be practically impossible.

Tool wear and surface integrity analysis of machined heat treated selective laser melted Ti-6Al-4V

In this study, the tool wear and surface integrity during machining of wrought and Selective LaserMelted (SLM) titanium alloy (after heat treatment) are studied. Face turning trails were carried out onboth the materials at different cutting speeds of 60,120 and 180 m/min. Cutting tools and machinedspecimens collected are characterized using scanning electron microscope, surface profiler and opticalmicroscope to study the tool wear, machined surface quality and machining induced microstructuralalterations. It was found that high cutting speeds lead to rapid tool wear during machining of SLMTi-6Al-4V materials. Rapid tool wear observed at high cutting speeds in machining SLM Ti-6Al-4Vresulted in damaging the surface integrity by 1) Deposition of chip/work material on the machinedsurface giving rise to higher surface roughness and 2) Increasing the depth of plastic deformationon the machined sub surface.

Analysis of a large-scale IT outsourcing "failure": what lessons can we learn?

Much of the research that has been carried out into outsourcing is based on relatively successful case studies. Yet drawing inferences from case studies when those with largely negative outcomes rarely see the light of day represents a significant problem. When negative cases are systematically unrepresented, there is less opportunity to subject theory to scrutiny. This chapter goes some way towards redressing this trend, by reporting on a large scale “selective” outsourcing arrangement that has been publicly described as a failure — the Australian Federal Government’s “whole of government” IT infrastructure outsourcing initiative. This initiative, originally promoted as likely to lead to a billion dollar saving, was abandoned early in 2001, after a damning public report by the Australian Auditor General. However, a detailed study of the initiative suggests that the “failure” occurred despite the project adhering to many of the recommended guidelines for successful outsourcing that had been derived from earlier case analysis. The findings have important implications for decision makers confronted with outsourcing choices. The study suggests that the risks of outsourcing are often downplayed, or ignored in the rush to reap the expected benefits. The study also suggests that expectations of savings from outsourcing IT are often substantially higher than those that have been empirically confirmed in the field. Decision makers are advised that key assumptions about costs, savings, managerial effort, and the effects of outsourcing on operational performance might be incorrect, and to plan for their outsourcing activity accordingly. They should pay particular attention to coordination and transaction costs, as these tend to be overlooked in the business case. These costs will be magnified if “best in breed” multiple-vendor outsourcing is chosen, and if contracts are kept short. Decision-makers are also warned of the difficulties they are likely to have at the end of an outsourcing contract if there is not a large and robust pool of alternative vendors willing to bid against the incumbent.

Determination of proline in wine using flow injection analysis with tris(2,2`-bipyridyl)ruthenium(II) chemiluminescence detection

Flow injection methodology is described for the determination of proline in red and white wines using tris(2,2′-bipyridyl)ruthenium(II) chemiluminescence detection. Selective conditions were achieved for proline at pH 10, while other amino acids and wine components did not interfere. The precision of the method was less than 1.00% (R.S.D.) for five replicates of a standard (4 × 10⁻⁶ M) and the detection limit was 1 × 10⁻⁸ M. The level of proline in white and sparkling wines using the developed methodology was equivalent to those achieved using HPLC-FMOC amino acid analysis. SPE removal of phenolic material was required for red wines to minimize Ru(bipy)₃³⁺ consumption and its associated effect on accuracy.

Polyhedral combinatorics of the cardinality constrained quadratic knapsack problem and the quadratic selective travelling salesman problem

This paper considers the Cardinality Constrained Quadratic Knapsack Problem (QKP) and the Quadratic Selective Travelling Salesman Problem (QSTSP). The QKP is a generalization of the Knapsack Problem and the QSTSP is a generalization of the Travelling Salesman Problem. Thus, both problems are NP hard. The QSTSP and the QKP can be solved using branch-and-cut methods. Good bounds can be obtained if strong constraints are used. Hence it is important to identify strong or even facet-defining constraints. This paper studies the polyhedral combinatorics of the QSTSP and the QKP, i.e. amongst others we identify facet-defining constraints for the QSTSP and the QKP, and provide mathematical proofs that they do indeed define facets.

The determination of morphine in the larvae of calliphora stygia using flow injection analysis and HPLC with chemiluminescence detection

Selective determination of morphine in the larvae of Calliphora stygia (Fabricius) (Diptera: Calliphoridae) using acidic potassium permanganate chemiluminescence detection coupled with flow injection analysis and high-performance liquid chromatography (HPLC) is described. Larvae of C. stygia were reared on minced meat substrates that had been spiked with varying concentrations of morphine. Morphine concentrations were chosen to reflect typical levels in human tissues from opiate overdose victims. After maturing on substrates, larvae were analyzed for the presence of morphine using chemiluminescence detection coupled to flow injection analysis and a rapid HPLC method. Analysis of the larval matrix by flow injection analysis with chemiluminescence detection indicated the presence of interferants capable of generating chemiluminescence. A rapid chromatographic separation with a monolithic column allowed selective determination of morphine in larvae using postcolumn chemiluminescence detection. Larvae of C. stygia reared on substrates containing morphine at concentrations of 500 and 1000 ng/g did not sequester morphine at detectable concentrations. Larvae reared on substrates containing morphine concentrations of 2500, 5000, and 10,000 ng/g tested positive for the drug at concentrations of 765, 2720, and 3010 ng/g, respectively.

Evaluation of selective growth in a Fe-2.8% Si single crystal using Rodrigues-Frank space

A Fe-2.8%Si single crystal was scratched in order to randomise the texture in the neighbourhood of the notch. Annealing resulted in recrystallization and grain growth starting from the deformed zone. Misorientations between the single crystal matrix and the grown grains were gathered and were studied in order to investigate the possibility for selective growth based on a specific misorientation. However, instead of studying the misorientation angle or axis profiles separately in a 1D or 2D projection a full misorientation analysis was carried out in the 3-dimensional Rodrigues-Frank misorientation space, which offers an unambiguous interpretation of the data because no features are hidden or masked by a projection. It is concluded that the selective growth phenomenon following the <110>26.5deg misorientation relationship is strongly supported by the gathered orientation data, after appropriately normalizing these data with respect to a random misorientation distribution.

Cost-effectiveness of cognitive behavioural therapy and selective serotonin reuptake inhibitors for major depression in children and adolescents

Objective:
To assess from a health sector perspective the incremental cost-effectiveness of cognitive behavioural therapy (CBT) and selective serotonin reuptake inhibitors (SSRIs) for the treatment of major depressive disorder (MDD) in children and adolescents, compared to ‘current practice’.
Method:
The health benefit is measured as a reduction in disability-adjusted life years (DALYs), based on effect size calculations from meta-analysis of randomised controlled trials. An assessment on second stage filter criteria (‘equity’; ‘strength of evidence’, ‘feasibility’ and ‘acceptability to stakeholders’) is also undertaken to incorporate additional factors that impact on resource allocation decisions. Costs and benefits are tracked for the duration of a new episode of MDD arising in eligible children (age 6–17 years) in the Australian population in the year 2000. Simulation-modelling techniques are used to present a 95% uncertainty interval (UI) around the cost-effectiveness ratios.
Results:
Compared to current practice, CBT by public psychologists is the most costeffective intervention for MDD in children and adolescents at A$9000 per DALY saved (95% UI A$3900 to A$24 000). SSRIs and CBT by other providers are less cost-effective but likely to be less than A$50 000 per DALY saved (> 80% chance). CBT is more effective than SSRIs in children and adolescents, resulting in a greater total health benefit (DALYs saved) than could be achieved with SSRIs. Issues that require attention for the CBT intervention include equity concerns, ensuring an adequate workforce, funding arrangements and acceptability to various stakeholders.
Conclusions:
Cognitive behavioural therapy provided by a public psychologist is the most
effective and cost-effective option for the first-line treatment of MDD in children and adolescents. However, this option is not currently accessible by all patients and will require change in policy to allow more widespread uptake. It will also require ‘start-up’ costs and attention to ensuring an adequate workforce.

Selective reduction in body fat mass and plasma leptin induced by angiotensin-converting enzyme inhibition in rats

Objective: There is emerging evidence that angiotensin stimulates adipocyte differentiation and lipogenesis. This study tested the hypothesis that inhibition of angiotensin II by treatment with an angiotensin-converting enzyme inhibitor, perindopril, would reduce fat mass in rats. Design: After a 12-day baseline, rats were divided into two groups: one was untreated and the other received perindopril (1.2 mg kg⁻¹ per day) in drinking water for 26 days.Subjects: In total, 16 male Sprague–Dawley rats aged 10 weeks at the start of the study. Measurements: Plasma leptin was measured in samples collected at baseline, half-way through and at the end of treatment. Body weight, food and water intake were measured daily throughout the experiment. Body fat mass, bone and lean mass were determined by dual energy X-ray absorptiometry (DEXA) at the end of the treatment period. Results: Daily food intake was the same in both groups throughout the study. By the end of treatment, animals receiving perindopril showed a modest reduction in weight gain relative to the untreated animals (62.4±5.0 g vs 73.0±4.0 g; P<0.05). DEXA analysis showed that body composition was greatly altered and the perindopril-treated group had 26% less body fat mass than the untreated group (61.0±5.2 g vs 44.4±4.2 g; P<0.01). The reduction in body fat mass was correlated with reductions in the weight of both the epididymal and retroperitoneal fat pads (P<0.001). Similarly, plasma leptin was reduced by perindopril treatment (4.64±0.56 ng ml⁻¹) compared to the untreated group (8.27±1.03 ng ml⁻¹; P<0.001). In contrast, there were no differences in lean or bone mass between the two groups.Conclusion: Oral treatment with perindopril selectively reduced body fat mass without influencing daily food intake. In contrast, there were no differences in lean or bone mass between the two groups

Manual on application of molecular tools in aquaculture and inland fisheries management. Part I : laboratory protocols, data management and analysis

The aim of this manual is to provide a comprehensive practical tool for the generation and analysis of genetic data for subsequent application in aquatic resources management in relation to genetic stock identification in inland fisheries and aquaculture. The material only covers general background on genetics in relation to aquaculture and fisheries resource management, the techniques and relevant methods of data analysis that are commonly used to address questions relating to genetic resource characterisation and population genetic analyses. No attempt is made to include applications of genetic improvement techniques e.g. selective breeding or producing genetically modified organisms (GMOs). The manual includes two ‘stand-alone’ parts, of which this is the second volume: Part 1 – Conceptual basis of population genetic approaches: will provide a basic foundation on genetics in general, and concepts of population genetics. Issues on the choices of molecular markers and project design are also discussed. Part 2 – Laboratory protocols, data management and analysis: will provide step-by-step protocols of the most commonly used molecular genetic techniques utilised in population genetics and systematic studies. In addition, a brief discussion and explanation of how these data are managed and analysed is also included. This manual is expected to enable NACA member country personnel to be trained to undertake molecular genetic studies in their own institutions, and as such is aimed at middle and higher level technical grades. The manual can also provide useful teaching material for specialised advanced level university courses in the region and postgraduate students. The manual has gone through two development/improvement stages. The initial material was tested at a regional workshop and at the second stage feedback from participants was used to improve the contents.

Selective chemical measurement based upon chemiluminescence detection

This thesis describes the utilisation of chemiluminescence (chemically generated light) for clinical diagnosis and process monitoring. Innovative instrumentation was developed for the direct monitoring of toxin levels in patients undergoing haemodialysis. This unique approach enables the efficacy of individual treatments to be continuously assessed thus enhancing patient outcomes.

Selectivity in separation using π electron-rich stationary phases for the comprehensive two-dimensional analysis of cafe espresso

The multidimensional high-performance liquid chromatography separations of the complex sample matrix found in café espresso coffee were completed on the propyl phenyl and butyl phenyl columns that contain 3 and 4 carbon atoms in the spacer chain, respectively. Phenyl type stationary phases are able to undergo unique π–π interactions with aromatic compounds. Previous works have found that there are differences in retention characteristics between these chain lengths and this was explored further here. It was found that when analysing the separations by quadrants, using a geometric approach to factor analysis and by measuring the normalised mean radius, subtle differences in the separations were observed and the butyl phenyl phase was more selective for the high to medium polarity species. However, there was very little difference in separation behaviour for the hydrophobic components within the coffee sample. Overall, the analysis of the entire separation showed very little difference.