167 research outputs found
Research Opportunities in Service Process Design
This paper presents an overview of the new issues and research opportunities related to four service operations design topicsâthe design of retail and e-tail service processes, design of service processes involving waiting lines and workforce staffing, service design for manufacturing, and re-engineering service processes. All four topics are motivated by new technologies (particularly web-based technologies) and require a multi-disciplinary approach to research. For each topic, the paper presents an overview of the topic, the relevant frameworks, and a discussion of the research opportunities
Phosphine-alkene ligand-mediated alkyl-alkyl and alkyl-halide elimination processes from palladium(II)
N-Diphenylphosphino-7-aza-benzobicyclo[2.2.1]hept-2-ene (2) behaves as a chelating phosphineâalkene ligand for Pd0 and PdII, promoting direct alkylâalkyl and indirect alkylâhalide reductive elimination reactions due to the stabilisation of the resulting bis(phosphineâalkene)Pd0 complex
Enkephalin is liberated from metorphamide and dynorphin A1-8 by endo-oligopeptidase A, but not by metalloendopeptidase EC 3.4.24.15
Catalytic dehydrocoupling of Amine-Boranes Using Cationic Zirconium(IV)-Phosphine Frustrated Lewis Pairs
A series
of novel, intramolecular ZrÂ(IV)/P frustrated Lewis pairs
(FLPs) based on cationic zirconocene fragments with a variety of ancillary
cyclopentadienyl and 2-phosphinoaryloxide (âOÂ(C<sub>6</sub>H<sub>4</sub>)ÂPR<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 dimethylamineâborane
(Me<sub>2</sub>NH·BH<sub>3</sub>) assessed. The FLP system [(C<sub>9</sub>H<sub>7</sub>)<sub>2</sub>ZrOÂ(C<sub>6</sub>H<sub>4</sub>)ÂP<sup>t</sup>Bu<sub>2</sub>]Â[BÂ(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 â„ 600 h<sup>â1</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 ZrÂ(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 ZrÂ(IV) Lewis acid
Electroanalytical detection of pindolol: comparison of unmodified and reduced graphene oxide modified screen-printed graphite electrodes
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 ÎŒMâ10.0 ÎŒM is found to
be possible whilst offering a limit of detection (3Ï) 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
The fabrication, characterisation and electrochemical investigation of screen-printed graphene electrodes
We report the fabrication, characterisation (SEM, Raman spectroscopy, XPS and ATR) and electrochemical
implementation of novel screen-printed graphene electrodes. Electrochemical characterisation of the fabricated
graphene electrodes is undertaken using an array of electroactive redox probes and biologically relevant
analytes, namely: potassium ferrocyanide(II), hexaammine-ruthenium(III) chloride, N,N,N0 ,N0-tetramethyl-pphenylenediamine
(TMPD), b-nicotinamide adenine dinucleotide (NADH), L-ascorbic acid (AA), uric acid (UA)
and dopamine hydrochloride (DA). The electroanalytical capabilities of the fabricated electrodes are also
considered towards the sensing of AA and DA. The electrochemical and (electro)analytical performances of
the fabricated screen-printed graphene electrodes are considered with respect to the relative surface
morphologies and material compositions (elucidated via SEM, Raman, XPS and ATR spectroscopy), the density
of electronic states (% global coverage of edge-plane like sites/defects) and the specific fabrication conditions
utilised. Comparisons are made between two screen-printed graphene electrodes and alternative graphite
based screen-printed electrodes. The graphene electrodes are fabricated utilising two different commercially
prepared âgrapheneâ inks, which have long screen ink lifetimes (43 hours), thus this is the first report of a true
mass-reproducible screen-printable graphene ink. Through employment of appropriate controls/comparisons
we are able to report a critical assessment of these screen-printed graphene electrodes. This work is of high
importance and demonstrates a proof-of-concept approach to screen-printed graphene electrodes that are
highly reproducible, paving the way for mass-producible graphene sensing platforms in the future
The fabrication, characterisation and electrochemical investigation of screen-printed graphene electrodes
We report the fabrication, characterisation (SEM, Raman spectroscopy, XPS and ATR) and electrochemical
implementation of novel screen-printed graphene electrodes. Electrochemical characterisation of the fabricated
graphene electrodes is undertaken using an array of electroactive redox probes and biologically relevant
analytes, namely: potassium ferrocyanide(II), hexaammine-ruthenium(III) chloride, N,N,N0 ,N0-tetramethyl-pphenylenediamine
(TMPD), b-nicotinamide adenine dinucleotide (NADH), L-ascorbic acid (AA), uric acid (UA)
and dopamine hydrochloride (DA). The electroanalytical capabilities of the fabricated electrodes are also
considered towards the sensing of AA and DA. The electrochemical and (electro)analytical performances of
the fabricated screen-printed graphene electrodes are considered with respect to the relative surface
morphologies and material compositions (elucidated via SEM, Raman, XPS and ATR spectroscopy), the density
of electronic states (% global coverage of edge-plane like sites/defects) and the specific fabrication conditions
utilised. Comparisons are made between two screen-printed graphene electrodes and alternative graphite
based screen-printed electrodes. The graphene electrodes are fabricated utilising two different commercially
prepared âgrapheneâ inks, which have long screen ink lifetimes (43 hours), thus this is the first report of a true
mass-reproducible screen-printable graphene ink. Through employment of appropriate controls/comparisons
we are able to report a critical assessment of these screen-printed graphene electrodes. This work is of high
importance and demonstrates a proof-of-concept approach to screen-printed graphene electrodes that are
highly reproducible, paving the way for mass-producible graphene sensing platforms in the future
Intoxicants and the invention of 'consumption'
In 1600 the word âconsumptionâ was a term of medical pathology describing the âwasting, petrification of thingsâ. By 1700 it was also a term of economic discourse: âIn commodities, the value rises as its quantity is less and vent greater, which depends upon it being preferred in its consumptionâ. 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 âconsumptionâ was an early term in the developing lexicon of political economy. In so doing the article demonstrates the important role of âintoxicantsâ â i.e. addictive and intoxicating commodities like alcohols and tobaccos â in shaping these early meanings and uses of âconsumptionâ. It outlines the discursive importance of intoxicants, both as the foci for discussions of âsuperfluousâ and ânecessaryâ 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
Multiple order-up-to policy for mitigating bullwhip effect in supply chain network
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 âhow much to orderâ 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 thatâthe 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
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
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