The removal of model viruses, poliovirus type 1 and canine parvovirus, during the purification of human albumin using ion-exchange chromatographic procedures

The manufacturing process for albumin in Australia is based primarily on ion-exchange chromatography. The capacity of ion-exchange matrices to remove non-enveloped viruses (canine parvovirus and poliovirus type 1) was assessed using a scaled-down chromatographic process which was shown to yield product meeting purity criteria set for the manufacturing process. Poliovirus type I and canine parvovirus were added at one tenth the volume of desalted and delipidated Supernatant II+III produced by traditional Cohn Fractionation from human plasma before the material was applied to DEAE and CM ion-exchangers connected in series. Samples were taken at equilibration, wash, elution and regeneration steps and the log clearance and reduction of the viruses calculated. The mean clearance and reduction factors for viral load of poliovirus type 1 were 5.3 logs and 3.2 logs, respectively and 1.8 logs and 1.8 logs for canine parvovirus

Teaching Excel VBA as a Problem Solving Tool for Chemical Engineering Core Courses

This project aims to initiate the teaching of user-friendly Excel Visual Basic for Application (VBA) programming in chemical engineering at the Hong Kong University of Science and Technology (HKUST) with the emphasis on relevant examples/projects selected from chemical engineering core courses. The course is designed with the emphasis on not only how to program, but also on problem solving and how to convert a chemical engineering problem into a working program. Several chemical engineering problems were selected as either projects or demonstration programs in order to allow students to experience the advantage of programming in Excel VBA. Comparison to other programming languages students had been previously taught and to other available software packages which do not have any programming requirement (e.g. Polymath) was made in these demonstration examples to let students understand the advantages or disadvantages of programming in Excel VBA. © 2010 The Institution of Chemical Engineers

Metstoich: Teaching Quantitative Metabolism and Energetics in Biochemical Engineering

Several analytical software packages are developed for research purpose and mainly focus on metabolic control analysis (MCA). GEPASI 3 is a widely used free biochemical reactions simulation software package. It simulates the kinetics of biochemical reaction systems and provides functions such as MCA, elementary mode analysis (EMA), optimization, and parameter fitting. E-Cell is an object-oriented, whole-cell simulation software package. MIST performs dynamic simulations, stoichiometric calculations, and MCA. JWS Online is an Internet-based metabolic simulator with collections of several metabolic models, and it can provide MCA to analyze the simulation results. Metstoich, a metabolic calculator for teaching purposes, was developed to introduce metabolism to students using quantitative principles. Metstoich has many novel features, such as linking practical engineering parameters with cell growth, product yield, energetics, analyzing the flux though any reaction pathway, and calculating how many nutrients are required for cell growth

An oxygen-rich enzyme matrix for biosensor construction based on clark oxygen electrode

We report a novel strategy to develop an oxygen-rich enzyme matrix biosensor based on the Clark oxygen electrode. For biosensors based on oxygen detection, the oxygen concentration in the enzyme matrix will significantly affect the biosensor performance. We demonstrate that, by using catalase in the enzyme matrix and hydrogen peroxide in the buffer solution, the concentration of oxygen in the enzyme matrix will be increased significantly. This is due to the release of oxygen from hydrogen peroxide through the enzymatic reaction by catalase. Consequently, the linear detection range will be broadened and the present oxygen-dependence will be alleviated significantly. copyright The Electrochemical Society

A bi-layer structured biosensor for the direct measurement of biopolymers and the effects of different size and levels of branching

This work reports a protocol that uses bilayer structured immobilization matrix by covalent binding to construct an amperometric biosensor for the rapid and direct biopolymer measurement within 5 min. It overcomes the normal barrier of biopolymers not being able to enter into the enzyme matrix due to their branched nature and large size. The outer layer containing enzymes covalent bind to the inner layer which links the enzymes to the surface of electrode. A biosensor for a polysaccharide (glycogen) is developed to demonstrate this strategy. The sensor shows good performance. The different size and branching level of the substrates (glucose)_n result in them exhibiting different signal responses, even they are composed of the same monomer, the reason of which has been tentatively analyzed. The method also has the advantages of being cost effective and having a simple immobilization preparation procedure. copyright The Electrochemical Society

Oxygen-rich enzyme or microbial matrix for extending detection range based on clark oxygen electrode

We report here a novel strategy based on Clark oxygen electrode for extending linear response detection range of enzyme or microbial matrix biosensor. The Clark oxygen electrode biosensor is mostly based on the oxygen consumption, thus the oxygen concentration in the enzyme matrix will affect the detection significantly. We demonstrate that using catalase in the enzyme matrix, hydrogen peroxide in the buffer solution, the concentration of oxygen in the matrix will be several times higher due to the release of oxygen from hydrogen peroxide by catalase in the matrix, thus the oxygen consumption range will be increased, and then the detection linear response range will be several times larger. Such oxygen-rich method compares favorably with that reported fluorocarbon pasting liquids or mediator based electrode, which provide a quite possible potential for enzyme and microbial biosensor practical application

Selenium associations in estuarine sediments: Redox effects

Selenium (Se) is a contaminant of concern in environments affected by discharges from smelting and coal-burning industries. Experiments have been performed to investigate the phase associations of selenium in contaminated sediments under a range of controlled redox conditions. In this study, Se sediment associations were examined using the BCR sequential extraction technique after stabilisation at different redox states. It was shown that although most of the sediment-bound Se is associated with the operationally-defined "organic/sulfide" fraction, as the measured redox potential of the system is increased, more Se moves into the "exchangeable" and "iron/manganese oxyhydroxide" fractions. In these fractions, contaminants can be expected to be more bioavailable. As the mass of Se absorbed to sediments is typically at least an order of magnitude higher than the mass dissolved in porewaters, significant Se exposure may result from oxidative shifts in Se sediment associations

Utilization of Incineration Waste Ash Residues in Portland Cement Clinker

MSWI (municipal solid waste incineration) ash and sewage sludge ash are used in part as raw materials for cement clinker production by taking advantage of the high contents of SiO2, Al2O3 and CaO. It is necessary to establish a material utilization system for the incineration waste ash residues instead of disposing these ashes into landfill. This paper is aimed to study the feasibility of replacing clinker raw materials by waste ash residue for cement clinker production. Sewage sludge ash, MSWI bottom ash and MSWI fly ash are the three main types of ashes being evaluated. The ashes were mixed into raw mixture with different portions to produce cement clinker in a laboratory furnace at approximately 1400 °C. X-ray diffraction and X-ray florescence techniques were used to analyze the phase chemistry and chemical composition of clinkers in order to compare these ash-based clinkers with commercial Portland cement clinker. Copyright © 2010, AIDIC Servizi S.r.l

Kinetics and equilibrium studies for the removal of cadmium ions by ion exchange resin

Cadmium is a highly toxic metal which is found in the effluent of battery manufacturing plants. In this study, the ability to remove cadmium ions using an ion exchange resin has been studied in single component sorption-exchange systems. The maximum sorption capacity of resin for cadmium ions has been reached at pH 5 and the value is 2.20 mmole/g resin. This value shows that resin can effectively remove cadmium ions. The equilibrium isotherms have been analyzed using the Langmuir, Freundlich and Redlich-Peterson isotherm equations and the experimental data are best described by the Redlich-Peterson model. A series of kinetics studies have been conducted in an agitated batch reactor. Two variables have been studied under two different pH values, namely, 2.5 and 5.0, - different initial metal ion concentrations and different masses of resin. The kinetics of sorption of the cadmium ions have been analyzed by three kinetic models, the pseudo-first order, pseudo-second order and Elovich models. The rate constants and the correlation coefficients of the three kinetic models have been calculated. The experimental data were compared on the basis of SSE values and the pseudo-second model order provides the best fit to the experimental data. © 2013 Elsevier Ltd. All rights reserved