Level of natural hepatotoxin (Indospicine) contamination in Australian camel meat

Camel meat production for human consumption and pet food manufacture accounts for a relatively small part of overall red meat production in Australia. Reliable statistical data for the Australian production and consumption of camel meat are not available; however, it is estimated that 300,000 feral camels roam within the desert of central Australia, with an annual usage of more than 3000 camels for human consumption, 2000 for pet food manufacture and a smaller number for live export. Despite a small Australian camel meat production level, the usage of camel meat for pet food has been restricted in recent years due to reports of serious liver disease and death in dogs consuming camel meat. This camel meat was found to contain residues of indospicine, a non-proteinogenic amino acid found in certain Indigofera spp., and associated with mild to severe liver disease in diverse animals after dietary exposure to this hepatotoxin. The extent of indospicine-contaminated Australian camel meat was previously unknown, and this study ascertains the prevalence of such residue in Australian camel meat. In this study, indospicine levels in ex situ (95 samples collected from an abattoir in Queensland) and in situ (197 samples collected from camels after field culling in central Australia) camel meat samples were quantitated using a validated ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The quantitation results showed 46.7% of the in situ- and 20.0% of the ex situ-collected camel meat samples were contaminated by indospicine (more than the limit of detection (LOD) of 0.05 mg kg^–1 fresh weight). The overall indospicine concentration was higher (p < 0.05) in the in situ-collected samples. Indospicine levels detected in the present study are considered to be low; however, a degree of caution must still be exercised, since the tolerable daily intake for indospicine is currently not available for risk estimation.     

The specific and sensitive detection of bacterial pathogens within 4 h using bacteriophage amplification

This paper describes a novel approach, termed the 'phage amplification assay', for the rapid detection and identification of specific bacteria. The technique is based on the phage lytic cycle with plaque formation as the assay end-point. It is highly sensitive, quantitative and gives results typically within 4 h. The assay comprises four main stages: (1) phage infection of target bacterium; (2) destruction of exogenous phage; (3) amplification of phage within infected host and (4) plaque formation from infected host with the aid of helper bacteria. A key component of this assay is a potent virucidal agent derived from natural plant extracts, pomegranate rind extract (PRE). In combination with ferrous sulphate PRE can bring about an 11 log-cycle reduction in phage titre within 3 min. This is achieved without any injury to the infected target bacteria. Subsequently, any resulting plaques are derived only from infected target organisms. Data are presented for a range of bacterial hosts including Pseudomonas aeruginosa, Salmonella typhimurium and Staphylococcus aureus. The detection limit for Ps. aeruginosa was 40 bacteria ml-1 in a time of 4 h and 600 bacteria m-1 for Salm. typhimurium. Application of the principles of this technology to other bacterial genera is discussed.     

AJ-p90: a novel protein of the perinuclear theca in human sperm subacrosome

A perinuclear theca protein of the human sperm subacrosome was detected using LH43 monoclonal antibody which was originally raised against human keratinocytes. Using indirect immunofluorescence, the antibody stained the acrosomal zone (AZ) of dried ejaculated spermatozoa but did not react with viable cells, thus suggesting that the antigen was intracellular. This was confirmed by immunogold electron microscopy which also revealed the ultrastructural localisation of the antigen to the subacrosomal fibrils. Throughout spermatogenesis the antigen was only detected on the AZ of developed testicular spermatozoa and its expression was continued during their epididymal passage. Biochemically, the protein was insoluble in Triton, and dithiothreitol (DTT) was required for its solubilisation. In Western blotting of sperm and keratinocyte lysates, the antibody detected similar 90-kDa protein doublets (AJ-p90). These biochemical features exclude the identity of AJ-p90 with various cyto- and karyo-skeletal antigens, including the intermediate filaments and microfilaments. AJ-p90 therefore represents a novel product of the subacrosomal perinuclear theca. The significance of these data is discussed together with the importance of the antibody for probing the perinuclear theca in normal and abnormal germ cells, including multinucleated spermatids which also showed reactivity with the antibody.     

Structural identification of highly polar nontarget contaminants in drinking water by ESI-FAIMS-Q-TOF-MS

Drinking water is a complex mixture that contains thousands of naturally occurring and anthropogenic contaminants. Liquid chromatography-mass spectrometry (LC-MS) methods have gained a tremendous popularity in monitoring nonvolatile, highly polar, and thermally labile components in drinking water. It is well recognized, however, that there are difficulties or limitations of LC-MS methods associated with (1) significant resources (time and effort) involved in sample preparation (preconcentration, fractionation, separation), (2) low screening capacity for target contaminants, and (3) insufficient capabilities for structural identification (elucidation) of nontarget contaminants. Consequently, LC-MS methods are mainly used for the detection of target contaminants (compounds identified in drinking water before), seldom for the structural identification of abundant nontarget pollutants (unidentified pollutants in drinking water), and almost never for the structural identification of nontarget components at a trace level. The paper presents a new method of electrospray ionization high field asymmetric waveform ion mobility spectrometry mass spectrometry (ESI-FAIMS-MS), which can detect a large number of water pollutants in a quick and convenient fashion without preconcentration, fractionation, derivatization, or column separation. Most importantly, the method provides structural identification of nontarget contaminants including species present in drinking water at a sub-parts-per-billion concentration level. The identification of previously unknown contaminants was based on mass measurements of investigated ions and their fragments in mass and tandem mass spectrometry. Elemental compositions of these ions, determined by mass measurements, were used to link dissociation patterns of investigated species with their chemical structures. Characterization of nontarget contaminants of chlorine-treated drinking water by ESI-FAIMS-MS has revealed many previously unknown disinfection byproducts. The most intriguing compound, from a group of highly polar hydroxycarboxylic acids discovered in the study, was the most abundant component of drinking water, glycolic acid. Glycolic acid (toxic to kidneys and associated with a moderate maternal toxicity) has never been considered as a drinking water contaminant, despite the fact that it is present in drinking water at a higher concentration (high ppm) than concentrations of highly polar water pollutants that had attracted most attention in the past. The process of structural elucidation of discovered pollutants, including ultratrace contaminants representing a variety of carboxylic acids, will be presented in detail. The structural identification of highly polar contaminants in drinking water presented in the paper is rarely reported in the literature. The key experimental feature of the ESI-FAIMS-MS method is FAIMS separation, which significantly improves the identification capabilities of mass spectrometry.     

Na incorporation in Mo and CuInSe2 from production processes

Results of characterization of thin films of Mo deposited by DC magnetron sputtering on soda-lime glass (Mo/SLG) and CuInSe₂ (CIS) on Mo/SLG are presented. The primary objective of the work was to clarify the factors determining the concentration of Na in commercial-grade CIS. Mo films were deposited by three laboratories manufacturing CIS thin film solar cells. Analysis was by secondary ion mass spectrometry, scanning electron microscopy and X-ray diffraction. Changes in Mo deposition parameters in general affected the Na level but there was no obvious link to any single Mo deposition parameter. Oxygen content directly affected the Na level. The Na behavior was not obviously connected to film preferred orientation. Selenization of the Mo layers was also examined. Elemental Se vapor was found to produce significantly less selenization than H₂Se. The amount of selenization was also strongly dependent upon Mo deposition conditions, although a specific source of the change in reaction rate was not found. Na distributions in the CIS deposited on the Mo were not limited by the diffusivity of the Na. The Na concentration in the CIS was increased by annealing the Mo films both with and without intentionally added Na. The Na level in the CIS appears to be set more by the CIS deposition process than by the Na concentration in the Mo so long as the Mo contains sufficient Na to saturate the available sites in the CIS.     

Characterisation of CuInS2/ Zn(Se,O)/ZnO solar cells as a function of Zn(Se,O) buffer deposition kinetics in a chemical bath

Thin‐film solar cells of CuInS₂/Zn(Se,O)/ZnO configuration have been studied from the point of view of their dependence on the Zn(Se,O) chemical bath deposition (CBD) conditions. The kinetics of deposition of the Zn(Se,O) buffer is followed during cell processing with a quartz crystal microbalance (QCM). Two different CBD growth mechanisms yield buffer layers with different properties. Under a predominant electroless deposition reaction, the resulting buffer layer has mixed ZnSe–ZnO composition. The solar cells with this buffer type show higher fill factor (FF) and lower open‐circuit voltage (V_oc). Under a chemical growth regime, the buffer layer has higher ZnSe proportion, giving rise to cells with higher V_OC, but lower FF and stability. The parameters of this second type of cell also show major dependence on illumination effects (light‐soaking effects). Electron‐beam‐induced current (EBIC) and cathodoluminescence (CL) measurements are carried out to characterise the CuInS₂/Zn(Se,O) junctions formed under the two buffer growth regimes. Cross‐sectional EBIC shows a wider space charge region (SCR) than expected for p‐CuInS₂ in contact with Zn(Se,O), and the p–n junction is driven within the CuInS₂ phase. These results reflect a chemical modification of CuInS₂, most probably caused by the ammonia of the bath solution. CL shows more defective interfaces when Zn(Se,O) is deposited under the chemical mechanism (slower deposition rate, hence longer contact time of the CuInS₂ with the bath solution) than under the electroless kinetics (faster deposition rate). Copyright © 2002 John Wiley & Sons, Ltd.     

Studies of the Structure and Reactivity of Soot

Vibrational spectroscopy, supplemented with other techniques, is providing a comprehensive picture of the structure and reactivity of soot. Reactions such as soot-NO₂/N₂O₄, soot-O₃, and soot-SO₂, at atmospheric and subatmospheric pressures and at different temperatures, have been studied. Determination of the kinetics and mechanisms of the formation of CO and CO₂ during the soot-O₃ reaction, and the effect of temperatures and the concentrations of soot and ozone on this reaction, have led to further insights about the soot structure. Examination of the identity and role of linkages bonding carbon layers together is underway. Application of the Elovich equation to determine initial rates for the formation of surface species in these reactions indicates that the soot-O₃ reaction is faster than the rapid soot-NO₂/ N₂O₄ reaction which, in turn, is faster than that of soot-SO₂. Oxidation of SO₂ to ionic sulfate, confirmed by isotopic substitution, occurs in the presence of soot, water vapor, and oxygen. The presence of simulated solar radiation results in the formation of both ionic and covalent sulfate species. The substrate, whether it is carbon black, cab-o-sil, or the glass walls of the reaction vessel, seems to play a role in the nonphotochemical oxidation of SO₂ to sulfate. The miscibilities of the reaction products of soot-O₃, soot-NO₂/N₂O₄, soot-SO₂, with water vary greatly and have implications for the depletion of tropospheric ozone in the presence of soot-containing particulates.     

Ébullition par Convection Forcée des Mélanges Eau‐Ammoniac dans un Tube Vertical

An experimental study has been conducted on the forced convective boiling heat transfer of ammonia‐water mixtures flowing inside a 6 mm inner diameter vertical smooth tube. Using a water‐heated double pipe type generator, the local heat transfer coefficients are measured inside the inner tube for a range of heat flux density (29.93 — 99.79 kW/m²), mass flux density (35.36 — 99.04 kg/m²·s), mass flow rate (0.001 — 0.03 kg/s) and ammonia mass concentration (49%, 55% and 61%). The effect of the experimental parameters on the heat transfer coefficients is analysed. Three methods are used to predict the boiling heat transfer coefficients. Experimental data were compared with the available correlations. The obtained results confirm the good performance of the Mishra et al. (1981) and Bennett‐Chen's (1980) correlations in predicting the convective boiling heat transfer coefficient of NH₃‐H₂O mixtures. These methods are able to predict the boiling heat transfer data within an average accuracy of ± 20 %.     

Thin film solvent‐free photopolymerization of n‐butyl acrylate. I. Static film studies

The results are presented for a detailed investigation involving the free‐radical photopolymerization of n‐butyl acrylate in the form of thin static films. The aim of this work is to benchmark the performance of a novel thin film spinning disk reactor that may be used for the continuous production of linear polymers using photoinitiation. Industrially relevant film thicknesses (200 μm to 1 mm) are studied as opposed to earlier work that looked into extremely thin films (5–25 μm). Such extreme film thicknesses will be difficult to sustain in a thin film reactor without adversely affecting the wettability of the reaction surface and the uniformity of the film. The effects of four main variables (film thickness, UV intensity, initiator concentration, and exposure time) are studied under static film conditions. A 366‐nm wavelength is utilized for the UV radiation with 2,2‐dimethoxy‐2‐phenylacetophenone (Irgacure 651) as the photoinitiator dissolved in n‐butyl acrylate. The molecular weights, polydispersities, and monomer conversions are measured by gel permeation chromatography. In a 400 μm thick film, conversions of >90% can be achieved with an exposure time of 40 s at a radiation intensity of 175 mW/cm². The results using the same polymerization system in the spinning disk reactor are presented and compared with the static film results in Part II of this series. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2079–2095, 2004