Analysis of pathogenic bacteria using exogenous volatile organic compound metabolites and optical sensor detection

A novel, low-cost and simple method for the detection of pathogenic bacteria is proposed. The approach is based on the generation of an exogenous volatile organic compound (VOC) produced by the addition of an enzyme substrate to the bacterial sample. The generated VOC is then trapped in agarose gel allowing colour development to take place; visual detection is then possible by both the naked eye and by colorimetric analysis. Agarose gel has been evaluated as both a suitable VOC trapping matrix and host for the colour-generating reagents. This proof of concept method allowed for the discrimination between β-glucosidase and β-alanyl aminopeptidase producing bacteria. Enterococcus faecium and Klebsiella pneumoniae are both β-glucosidase producers and generated a yellow colour within agarose gels upon enzymatic hydrolysis of 2-nitrophenyl-β-D-glucoside. Pseudomonas aeruginosa is a known β-alanyl aminopeptidase producer and was shown to hydrolyse the trifluoroacetic acid (TFA) salt of 3-amino-N-phenylpropanamide resulting in the development of an orange colour within agarose gels spiked with the sodium salt of 1,2-naphthoquinone-4-sulfonic acid. 3-Amino-N-phenylpropanamide (as its TFA salt) and 2-nitrophenyl-β-D-glucoside concentrations of 20 μg mL−1 (or 72 μmol L−1) and 100 μg mL−1 (or 332 μmol L−1), respectively were the minimum quantities required for colour production following 18 h of incubation. The use of 3-amino-N-phenylpropanamide, TFA salt indicated that synthesised enzyme substrates can be tailor-made to liberate exogenous VOCs for colour generation

How safe are herbal products?

In the search for cures for his ailments, man discovered many healing and toxic properties of plants. Some were found to cure certain diseases while others were found to exert dramatic effects on the body. Consequently, most natural products used today as medicines are derived from plants.peer-reviewe

An analysis of the price behaviour of selected vegetables at a New Zealand auction : a thesis presented in partial fulfillment of the requirements for the degree of Master of Business Studies at Massey University

The immediate and short run behaviour of prices and volumes of eighteen vegetables at auction are examined. The objectives were to describe the behaviour of weekly prices and volumes and to investigate various relationships. The data analysed are weekly volume and turnover for eighteen vegetables at a Palmerston North auction for a three year period. Various climatological variables relating to the same period were also analysed. Much of the descriptive analysis relies on the techniques of Exploratory Data Analysis; boxplots, letterplots, and a resistant smoother are used extensively. These methods facilitate the analysis of the behaviour of prices and volumes over time. The auction marketing system is discussed at length, with particular emphasis on the effect of length of run on supply response. Various relationships are examined predominantly using stepwise reqression. These include: current price and quantity; current quantity and lagged price; quantity and month of the year; price and month of the year; price and various weather variables; quantity and various weather variables; current price and lagged price. Some transformations are used to try to get a more linear relationship between price and quantity. This relied on fitting several resistant lines, another EDA technique. The interdependence or interrelationship of prices examined using Principal Components Analysis, and principal components were extracted and described. Some useful insights into the behaviour of the market are gained. Immediate run price variation, that is from week to week, is quite large and this is reflected in low R-squared values for the price-volume relationships. The relationship between current marketed volume and lagged prices was also investigated. The results indicate that in the immediate run, using weekly prices, this relationship is weak. Arguably the most useful analysis was the monthly price boxplots which give a clear graphic display of the behaviour of prices. These and the other plots give indications as to when prices were highest and lowest. They may be useful to growers in planning production and harvesting. It was discovered that weekly prices were more variable than weekly volumes for 10 vegetables, less variable for six vegetables, and equally variable for two vegetables. 0ften the highest weekly price did not coincide with the lowest weekly supply, and the lowest price did not correspond to the highest supply. This suggests that bidders under or over estimate the quantity on the floor and each other's requirements

A non-perturbative approach to quantum chromodynamics

The approach of calculating non-perturbative effects in Quantum Chromodynamics by expanding about non-trivial classical solutions of the equation of motion is described. Some of the techniques required for this are developed in references [l,2,3] on which this thesis is predominantly based. The general self-dual solutions are discussed. With these as background fields the Green and massless Dirac functions are solved for arbitrary group representation. Then with the help of these the determinants and collective coordinate zero modes required for the first order quantum corrections ar'3 calculated

Interactions of grapefruit juice with drugs

Interactions between grapefruit juice and oral drugs have been reported in the literature. The constituents of the juice that give rise to pharmacokinetic interactions have not been identified with certainty. It has been suggested that the mechanisms may involve inhibition of intestinal cytochrome P450 CYP3A4 isozyme and of drug efflux transporters. There are several variables that may influence the clinical significance of the drug-food interactions. In the pharmacy practice setting, the major concern is the increased bioavailability of drugs having a narrow therapeutic index.peer-reviewe

International Actors and Internal Conflicts

Surveys the recent literature relating to conflict and mediation activities, and presents a range of options available to states, international organizations, regional organizations, and NGOs seeking to mediate internal conflicts

Revenue sharing in a sports league with an open market in playing talent

In this paper we develop an economic model of a professional sports league, in which the teams acquire playing talent in an external market. There have been several earlier formulations of this open model and all rely upon an inappropriately specified revenue function. Team revenues should depend upon the absolute quality of the teams, as well as their relative quality measured by win-percent. An inference that has been cited widely in this literature is that revenue sharing increases competitive inequality. We show that this analysis is flawed. If the revenue function is specified appropriately, gate revenue sharing always reduces competitive inequality

New directions in the analysis of inequality and poverty

Over the last four decades, academic and wider public interest in inequality and poverty has grown substantially. In this paper we address the question: what have been the major new directions in the analysis of inequality and poverty over the last thirty to forty years? We draw attention to developments under seven headings: changes in the extent of inequality and poverty, changes in the policy environment, increased scrutiny of the concepts of ‘poverty’ and inequality’ and the rise of multidimensional approaches, the use of longitudinal perspectives, an increase in availability of and access to data, developments in analytical methods of measurement, and developments in modelling