165 research outputs found

    A Coherent Tidal Datum for the Torres Strait

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    The Torres Strait is a complex waterway to the north of Australia linking the Arafura and Coral Seas. Sea level data from 13 islands were provided with the intention of validating the GPS extension of AUSGeoid98 to the Torres Strait. A comparison between the Australian Height Datum (AHD) determined from the AUSGeoid98 model and Mean Sea Level (MSL) identified differences of up to 1.57m. A coherent tidal datum was established with a seasonal adjustment to the long-term level from Thursday Island. The seasonally adjusted MSL from this study should be considered as an approximation of AHD in the Torres Strait.El Estrecho de Torres es un canal complejo al norte de Australia, que conecta los Mares de Arafura y Coral. Se proporcionaron datos del nivel del mar de 13 islas, con la intenciĂłn de validar la extensiĂłn GPS de AUSGeoid98 al Estrecho de Torres. Una comparaciĂłn entre el Plano de Referencia Australiano (AHD) determinado a partir del modelo AUSGeoid98 y el Nivel Medio del Mar (MSL) identificĂł diferencias de hasta 1,57m. Se creĂł un Datum de Mareas coherente con un reajuste de nivel estacional a largo plazo a partir de la Isla Thursday. El MSL reajustado estacionalmente a partir de este estudio deberĂ­a ser considerado como una aproximaciĂłn del AHD en el Estrecho de Torres.Le dĂ©troit de Torres est une voie navigable complexe au nord de l‘Australie, qui relie les mers d‘Arafura et de Coral. Les donnĂ©es sur le niveau de la mer de 13 Ăźles ont Ă©tĂ© fournies dans l‘intention de valider l‘extension du GPS d‘AUSGeoid98 au dĂ©troit de Torres. Une comparaison entre le systĂšme de rĂ©fĂ©rence australien (AHD) dĂ©terminĂ© Ă  partir du modĂšle de AUSGeoid98 et le niveau moyen de la mer (MSL) a mis en Ă©vidence des diffĂ©rences allant jusqu‘à 1,57m. Un zĂ©ro des marĂ©es cohĂ©rent a Ă©tĂ© Ă©tabli avec une correction saisonniĂšre du niveau Ă  long terme, Ă  partir de Thursday Island. Le MSL corrigĂ© des variations saisonniĂšres de cette Ă©tude doit ĂȘtre considĂ©rĂ© comme une approximation du AHD dans le dĂ©troit de Torres

    Forensic electrochemistry: indirect electrochemical sensing of the components of the new psychoactive substance "Synthacaine"

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    “Synthacaine” is a New Psychoactive Substance which is, due to its inherent psychoactive properties, reported to imitate the effects of cocaine and is therefore consequently branded as “legal cocaine”. The only analytical approach reported to date for the sensing of “Synthacaine” is mass spectrometry. In this paper, we explore and evaluate a range of potential analytical techniques for its quantification and potential use in the field screening “Synthacaine” using Raman spectroscopy, presumptive (colour) testing, High Performance Liquid Chromatography (HPLC) and electrochemistry. HPLC analysis of street samples reveals that “Synthacaine” comprises a mixture of methiopropamine (MPA) and 2-aminoindane (2-AI). Raman spectroscopy and presumptive (colour) tests, the Marquis, Mandelin, Simon’s and Robadope test, are evaluated towards a potential in-the-field screening approach but are found to not be able to discriminate between the two when they are both present in the same sample, as is the case in the real street samples. We report for the first time a novel indirect electrochemical protocol for the sensing of MPA and 2-AI which is independently validated in street samples with HPLC. This novel electrochemical approach based upon one-shot disposable cost effective screen-printed graphite macroelectrodes holds potential for in-the-field screening for “Synthacaine”. Introduction In the last few years there has been a striking increase in the sale of “New Psychoactive Substances” (NPSs) formerly known as “legal highs”.1 These chemicals may be bought through the internet at low cost and are sometimes pure compounds which display highly similar chemical structures to existing controlled substances within the phenethylamine class. “Synthacaine” is a slang term derived from “synthetic” and “cocaine

    Forensic electrochemistry: simultaneous voltammetric detection of MDMA and its fatal counterpart "Dr Death" (PMA)

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    The simultaneous detection of substances present in drugs of abuse is increasingly important since some materials are known for their high mortality rate. One drug that received considerable attention is para-methoxyamphetamine (PMA), commonly known as ‘Dr Death’ – this substance is linked with several deaths internationally and can often be found together with 3,4-methylenedioxymethamphetamine (MDMA) in drugs sold under the alias “ecstasy”, a very popular drug of abuse. This work reports for the first time the detection and quantification of MDMA and PMA simultaneously through an electrochemical technique using screen-printed graphite electrodes (SPEs). The electroanalytical sensing of MDMA/PMA, MDMA and PMA are explored directly at bare unmodified SPEs yielding a detection limit (3σ) corresponding to 0.25 ÎŒg mL−1/0.14 ÎŒg mL−1 for MDMA/PMA, 0.04 ÎŒg mL−1 MDMA and 0.03 ÎŒg mL−1 PMA. Raman spectroscopy and presumptive colour tests were also performed on MDMA/PMA, MDMA and PMA using the Marquis, Mandelin, Simon's and Robadope tests but were found to not be able discriminate when PMA and MDMA are both present in the same samples. We report a novel electrochemical protocol for the sensing of PMA and MDMA which is independently validated in a synthetic (MDMA/PMA) sample with HPLC

    Catalytic dehydrocoupling of Amine-Boranes Using Cationic Zirconium(IV)-Phosphine Frustrated Lewis Pairs

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    A series of novel, intramolecular Zr­(IV)/P frustrated Lewis pairs (FLPs) based on cationic zirconocene fragments with a variety of ancillary cyclopentadienyl and 2-phosphinoaryloxide (−O­(C<sub>6</sub>H<sub>4</sub>)­PR<sub>2</sub>, R = <sup>t</sup>Bu and 3,5-CF<sub>3</sub>-(C<sub>6</sub>H<sub>3</sub>)) ligands are reported and their activity as catalysts for the dehydrocoupling of dimethylamine–borane (Me<sub>2</sub>NH·BH<sub>3</sub>) assessed. The FLP system [(C<sub>9</sub>H<sub>7</sub>)<sub>2</sub>ZrO­(C<sub>6</sub>H<sub>4</sub>)­P<sup>t</sup>Bu<sub>2</sub>]­[B­(C<sub>6</sub>F<sub>5</sub>)<sub>4</sub>] is shown to give unprecedented turnover frequencies (TOF) for a catalyst based on a group 4 metal (TOF ≄ 600 h<sup>–1</sup>), while also proving to be the most efficient FLP catalyst reported to date. The mechanism of this reaction has been probed using analogous intermolecular Zr­(IV)/P FLPs, permitting deconvolution of the reactions taking place at both the Lewis acidic and basic sites. Elucidation of this mechanism revealed an interesting cooperative two-cycle process where one cycle is FLP mediated and the other, a redistribution of a linear diborazane intermediate, relies solely on the presence of a Zr­(IV) Lewis acid

    Electroanalytical detection of pindolol: comparison of unmodified and reduced graphene oxide modified screen-printed graphite electrodes

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    Recent work has reported the first electroanalytical detection of pindolol using reduced graphene oxide (RGO) modified glassy carbon electrodes [S. Smarzewska and W. Ciesielski, Anal. Methods, 2014, 6, 5038] where it was reported that the use of RGO provided significant improvements in the electroanalytical signal in comparison to a bare (unmodified) glassy carbon electrode. We demonstrate, for the first time, that the electroanalytical quantification of pindolol is actually possible using bare (unmodified) screenprinted graphite electrodes (SPEs). This paper addresses the electroanalytical determination of pindolol utilising RGO modified SPEs. Surprisingly, it is found that bare (unmodified) SPEs provide superior electrochemical signatures over that of RGO modified SPEs. Consequently the electroanalytical sensing of pindolol is explored at bare unmodified SPEs where a linear range between 0.1 ÎŒM–10.0 ÎŒM is found to be possible whilst offering a limit of detection (3σ) corresponding to 0.097 ÎŒM. This provides a convenient yet analytically sensitive method for sensing pindolol. The optimised electroanalytical protocol using the unmodified SPEs, which requires no pre-treatment (electrode polishing) or electrode modification step (such as with the use of RGO), was then further applied to the determination of pindolol in urine samples. This work demonstrates that the use of RGO modified SPEs have no significant benefits when compared to the bare (unmodified) alternative and that the RGO free electrode surface can provide electro-analytically useful performances

    Extreme water levels, waves and coastal impacts during a severe tropical cyclone in northeastern Australia: a case study for cross-sector data sharing

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    Severe tropical cyclone (TC) Debbie made landfall on the northern Queensland coast of Australia on 27 March 2017 after crossing the Great Barrier Reef as a slow-moving Category 4 system. Groups from industry, government and academia collected coastal hazard and impact data before, during and after the event and shared these data to produce a holistic picture of TC Debbie at the coast. Results showed the still water level exceeded the highest astronomical tide by almost a metre. Waves added a further 16&thinsp;% to water levels along the open coast, and were probably unprecedented for this area since monitoring began. In most places, coastal barriers were not breached and as a result there was net offshore sand transport. If landfall had occurred 2&thinsp;h earlier with the high tide, widespread inundation and overwash would have ensued. This paper provides a case study of effective cross-sector data sharing in a natural hazard context. It advocates for a shared information platform for coastal extremes in Australia to help improve the understanding and prediction of TC-related coastal hazards in the future.</p

    Multiple order-up-to policy for mitigating bullwhip effect in supply chain network

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    This paper proposes a multiple order-up-to policy based inventory replenishment scheme to mitigate the bullwhip effect in a multi-stage supply chain scenario, where various transportation modes are available between the supply chain (SC) participants. The proposed policy is similar to the fixed order-up-to policy approach where replenishment decision “how much to order” is made periodically on the basis of the predecided order-up-to inventory level. In the proposed policy, optimal multiple order-up-to levels are assigned to each SC participants, which provides decision making reference point for deciding the transportation related order quantity. Subsequently, a mathematical model is established to define optimal multiple order-up-to levels for each SC participants that aims to maximize overall profit from the SC network. In parallel, the model ensures the control over supply chain pipeline inventory, high satisfaction of customer demand and enables timely utilization of available transportation modes. Findings from the various numerical datasets including stochastic customer demand and lead times validate that—the proposed optimal multiple order-up-to policy based inventory replenishment scheme can be a viable alternative for mitigating the bullwhip effect and well-coordinated SC. Moreover, determining the multiple order-up-to levels is a NP hard combinatorial optimization problem. It is found that the implementation of new emerging optimization algorithm named bacterial foraging algorithm (BFA) has presented superior optimization performances. The robustness and applicability of the BFA algorithm are further validated statistically by employing the percentage heuristic gap and two-way ANOVA analysis

    Genetically manipulated phages with improved pH resistance for oral administration in veterinary medicine

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    Orally administered phages to control zoonotic pathogens face important challenges, mainly related to the hostile conditions found in the gastrointestinal tract (GIT). These include temperature, salinity and primarily pH, which is exceptionally low in certain compartments. Phage survival under these conditions can be jeopardized and undermine treatment. Strategies like encapsulation have been attempted with relative success, but are typically complex and require several optimization steps. Here we report a simple and efficient alternative, consisting in the genetic engineering of phages to display lipids on their surfaces. Escherichia coli phage T7 was used as a model and the E. coli PhoE signal peptide was genetically fused to its major capsid protein (10A), enabling phospholipid attachment to the phage capsid. The presence of phospholipids on the mutant phages was confirmed by High Performance Thin Layer Chromatography, Dynamic Light Scattering and phospholipase assays. The stability of phages was analysed in simulated GIT conditions, demonstrating improved stability of the mutant phages with survival rates 102107 pfu.mL1 higher than wild-type phages. Our work demonstrates that phage engineering can be a good strategy to improve phage tolerance to GIT conditions, having promising application for oral administration in veterinary medicine.This work was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit and COMPETE 2020 (POCI-01-0145-FEDER-006684) and under the scope of the Project PTDC/BBB-BSS/6471/2014 (POCI-01-0145-FEDER-016678). Franklin L. Nobrega and Ana Rita Costa acknowledge FCT for grants SFRH/BD/86462/2012 and SFRH/BPD/94648/2013, respectively. Melvin F. Siliakus acknowledges funding from the Biobased Ecologically Balanced Sustainable Industrial Chemistry (BE-BASIC) foundation. Electron microscopy work was performed at the Wageningen Electron Microscopy Centre (WEMC) of Wageningen University

    Intoxicants and the invention of 'consumption'

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    In 1600 the word ‘consumption’ was a term of medical pathology describing the ‘wasting, petrification of things’. By 1700 it was also a term of economic discourse: ‘In commodities, the value rises as its quantity is less and vent greater, which depends upon it being preferred in its consumption’. The article traces the emergence of this key category of economic analysis to debates over the economy in the 1620s and subsequent disputes over the excise tax, showing how ‘consumption’ was an early term in the developing lexicon of political economy. In so doing the article demonstrates the important role of ‘intoxicants’ – i.e. addictive and intoxicating commodities like alcohols and tobaccos – in shaping these early meanings and uses of ‘consumption’. It outlines the discursive importance of intoxicants, both as the foci for discussions of ‘superfluous’ and ‘necessary’ consumption and the target of legislation on consumption. And it argues that while these discussions had an ideological dimension, or dimensions, they were also responses to material increases in the volume and diversity of intoxicants in early seventeenth-century England. By way of conclusion the article suggests the significance of the Low Countries as a point of reference for English writers, as well as a more capacious and semantically sensitive approach to changes in early-modern consumption practices
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