School of Chemistry - Research Publications

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    The incidence and outcome of septic shock patients in the absence of early-goal directed therapy
    Ho, BCH ; Bellomo, R ; McGain, F ; Jones, D ; Naka, T ; Wan, L ; Braitberg, G (BIOMED CENTRAL LTD, 2006)
    INTRODUCTION: The purpose of the present study was to measure the incidence and outcome of septic patients presenting at the emergency department (ED) with criteria for early goal-directed therapy (EGDT). METHOD: This hospital-based, retrospective, observational study using prospectively collected electronic databases was based in a teaching hospital in Melbourne, Australia. We conducted outcome-blinded electronic screening of patients with infection admitted via the ED from 1 January 2000 to 30 June 2003. We obtained data on demographics, laboratory and clinical features on admission. We used paper records to confirm electronic identification of candidates for EGDT and to study their treatment. We followed up all patients until hospital discharge or death. RESULTS: Of 4,784 ED patients with an infectious disease diagnosis, only 50 fulfilled published clinical inclusion criteria for EGDT (EGDT candidates). Of these patients, 37 (74%) survived their hospital admission, two (4%) died in the ED, eight (16%) died in the intensive care unit and three (6%) died in the ward. After review of all ward cardiac arrests and non-NFR ('not for resuscitation') ward deaths, we identified a further two potential candidates for EGDT for an overall mortality of 28.8% (15 out of 52 patients). Analysis of treatment showed that twice as many (70%) of the EGDT candidates received vasopressor therapy in the ED, and their initial mean central venous pressure (10.8 mmHg) was almost twice that in patients from the EGDT study conducted by Rivers and coworkers. CONCLUSION: In an Australian teaching hospital candidates for EGDT were uncommon and, in the absence of an EGDT protocol, their mortality was lower than that reported with EGDT.
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    Mechanisms for the ultrasonic enhancement of dairy whey ultrafiltration
    Muthukumaran, S ; Kentish, SE ; Ashokkumar, M ; Stevens, GW (ELSEVIER SCIENCE BV, 2005-08-01)
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    National Chemistry Week Roadshow and other Outreach Activities
    MOYLAN, M ; Clark, M (Royal Australian Chemical Institute, 2005)
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    Effect of surfactants on the rate of growth of an air bubble by rectified diffusion
    Lee, J ; Kentish, S ; Ashokkumar, M (AMER CHEMICAL SOC, 2005-08-04)
    The rectified diffusion growth of a single air bubble levitated in an acoustic field (frequency = 22.35 kHz) in water and in aqueous solutions containing surfactants (sodium dodecyl sulfate and sodium dodecylbenzene sulfonate) was investigated. As reported by Crum (J. Acoust. Soc. Am. 1980, 68, 203), the presence of surfactants at the bubble/liquid interface enhanced the growth rate of the bubble by rectified diffusion. It is suggested in this paper that in addition to the effect of surfactants on the surface tension and interfacial resistance to mass transfer, the effect of surface rheological properties may also contribute to the cause of the enhancement observed in the bubble growth rate.
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    Determination of the size distribution of sonoluminescence bubbles in a pulsed acoustic field
    Lee, J ; Ashokkumar, M ; Kentish, S ; Grieser, F (AMER CHEMICAL SOC, 2005-12-07)
    A simple method is described for determining the size of sonoluminescence bubbles generated by acoustic cavitation. The change in the intensity of sonoluminescence, from 4 ms pulses of 515 kHz ultrasound, as a function of the "off" time between acoustic pulses, is the basis of the method. The bubble size determined in water was in the range of 2.8-3.7 mum.
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    The dissolution of a stationary spherical bubble beneath a flat plate
    Kentish, S ; Lee, J ; Davidson, M ; Ashokkumar, M (PERGAMON-ELSEVIER SCIENCE LTD, 2006-12)
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    Gas phase ion chemistry of biomolecules. part 51 - Tuning the gas phase redox properties of copper(II) ternary complexes of terpyridines to control the formation of nucleobase radical cations
    Lam, AKY ; Abrahams, BF ; Grannas, MJ ; McFadyen, WD ; O'Hair, RAJ (ROYAL SOC CHEMISTRY, 2006)
    Electrospray ionization (ESI) tandem mass spectrometry (MS/MS) of ternary copper(II) complexes of [Cu(terpyX)(M)]2+ (where terpyX = is a substituted 2,2':6',2''-terpyridine ligand; M = the nucleobases: adenine, guanine, thymine and cytosine) was examined as a means of forming radical cations of nucleobases in the gas phase. The following substituents were examined: 4'-NMe2-2,2':6',6''-terpyridine; 4'-OH-2,2':6',6''-terpyridine; 4'-F-2,2':6',6''-terpyridine; 2,2':6',6''-terpyridine; 4'-Cl-2,2':6',6''-terpyridine; 4'-Br-2,2':6',6''-terpyridine; 4'-CO2H-2,2':6',6''-terpyridine; 4'-NO2-2,2':6',6''-terpyridine and 6,6''-dibromo-2',2:6',2''-terpyridine. Each of the ternary complexes [Cu(terpyX)(M)]2+ was mass selected and subjected to collision induced dissociation (CID) in a quadrupole ion trap. The types of fragmentation reactions observed for these complexes depend on the nature of the substituent on the terpyridine ligand, while the yields of the radical cations of the nucleobases follow the order of their ionization energies (IEs): G (lowest IE) > A > C > T (highest IE). In general, radical cation formation is favoured for electron withdrawing substituents (e.g. NO2) while loss of the neutral nucleobase is favoured for electron donating substituents (e.g. NMe2). Loss of the protonated nucleobase is a major fragmentation pathway for the OH substituted terpyridine system, consistent with its ability to bind to a metal centre as a deprotonated ligand. Crystal structure determinations of (6,6''-dibromo-2',2:6',2''-terpyridine)bis(nitrato)copper(II) and diaqua(4'-oxo-2,2':6',6''-terpyridine)copper(II) nitrate monohydrate were performed and correlated with the ESI results.