Matrix-assisted diffusion-ordered spectroscopy:mixture resolution by NMR using SDSmicelles

Diffusion-ordered spectroscopy (DOSY) is a powerful technique for mixture analysis, but in its basic form it cannot separate the component spectra for species with very similar diffusion coefficients. It has been recently demonstrated that the component spectra of a mixture of isomers with nearly identical diffusion coefficients (the three dihydroxybenzenes) can be resolved using matrix-assisted DOSY (MAD), in which diffusion is perturbed by the addition of a co-solute such as a surfactant [R. Evans, S. Haiber, M. Nilsson, G. A. Morris, Anal. Chem. 2009, 81, 4548-4550]. However, little is known about the conditions required for such a separation, for example, the concentrations and concentration ratios of surfactant and solutes. The aim of this study was to explore the concentration range over whichmatrix-assisted DOSY using the surfactant SDS can achieve diffusion resolution of a simple model set of isomers, the monomethoxyphenols. The results show that the separation is remarkably robust with respect to both the concentrations and the concentration ratios of surfactant and solutes, supporting the idea that MAD may become a valuable tool formixture analysis. © 2010 John Wiley & Sons, Ltd.

Isomer resolution by micelle-assisted diffusion-ordered spectroscopy

Diffusion-ordered NMR spectroscopy ("DOSY") is a useful tool for the identification of mixture components. In its basic form it relies on simple differences in hydrodynamic radius to distinguish between different species. This can be very effective where species have significantly different molecular sizes, but generally fails for isomeric species. The use of surfactant co-solutes can allow isomeric species to be distinguished by virtue of their different degrees of interaction with micelles or reversed micelles. The use of micelle-assisted DOSY to resolve the NMR spectra of isomers is illustrated for the case of the three dihydroxybenzenes (catechol, resorcinol, and hydroquinone) in aqueous solution containing sodium dodecyl sulfate micelles, and in chloroform solution containing AOT reversed micelles. © 2009 American Chemical Society.

Quantitative interpretation of diffusion-ordered NMR spectra:can we rationalize small molecule diffusion coefficients?

Appealingly simple: A new method is described that allows the diffusion coefficient of a small molecule to be estimated given only the molecular weight and the viscosity of the solvent used. This method makes possible the quantitative interpretation of the diffusion domain of diffusion-ordered NMR spectra (see picture). © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Facile route to conformal hydrotalcite coatings over complex architectures:a hierarchically ordered nanoporous base catalyst for FAME production

An alkali- and nitrate-free hydrotalcite coating has been grafted onto the surface of a hierarchically ordered macroporous-mesoporous SBA-15 template via stepwise growth of conformal alumina adlayers and their subsequent reaction with magnesium methoxide. The resulting low dimensional hydrotalcite crystallites exhibit excellent per site activity for the base catalysed transesterification of glyceryl triolein with methanol for FAME production.

All-optical binary counter

We experimentally demonstrate an all-optical binary counter composed of four semiconductor optical amplifier based all-optical switching gates. The time-of-flight optical circuit operates with bit-differential delays between the exclusive-OR gate used for modulo-2 binary addition and the AND gate used for binary carry detection. A movie of the counter operating in real time is presented.

Parametric aggregation in ordered weighted averaging

Incorporating further information into the ordered weighted averaging (OWA) operator weights is investigated in this paper. We first prove that for a constant orness the minimax disparity model [13] has unique optimal solution while the modified minimax disparity model [16] has alternative optimal OWA weights. Multiple optimal solutions in modified minimax disparity model provide us opportunity to define a parametric aggregation OWA which gives flexibility to decision makers in the process of aggregation and selecting the best alternative. Finally, the usefulness of the proposed parametric aggregation method is illustrated with an application in metasearch engine. © 2011 Elsevier Inc. All rights reserved.

Reverse resource exchanges in service supply chains:the case of returnable transport packaging

Purpose: The purpose of this paper is to understand how reverse resource exchanges and resource dependencies are managed in the service supply chain (SSC) of returnable transport packaging (RTP). Design/methodology/approach: A single case study was conducted in the context of automotive logistics focusing on the RTP SSC. Data were collected through 16 interviews, primarily with managers of a logistics service provider (LSP) and document analysis of contractual agreements with key customers of the packaging service. Findings: Resource dependencies among actors in the SSC result from the importance of the RTP for the customer’s production processes, the competition among users for RTP and the negative implications of the temporary unavailability of RTP for customers and the LSP (in terms of service performance). Amongst other things, the LSP is dependent on its customers and third-party users (e.g. the customer’s suppliers) for the timely return of package resources. The role of inter-firm integration and collaboration, formal contracts as well as customers’ power and influence over third-party RTP users are stressed as key mechanisms for managing LSP’s resource dependencies. Research limitations/implications: A resource dependence theory (RDT) lens is used to analyse how reverse resource exchanges and associated resource dependencies in SSCs are managed, thus complementing the existing SSC literature emphasising the bi-directionality of resource flows. The study also extends the recent SSC literature stressing the role of contracting by empirically demonstrating how formal contracts can be mobilised to explicate resource dependencies and to specify, and regulate, reverse exchanges in the SSC. Practical implications: The research suggests that logistics providers can effectively manage their resource dependencies and regulate reverse exchanges in the SSC by deploying contractual governance mechanisms and leveraging their customers’ influence over third-party RTP users. Originality/value: The study is novel in its application of RDT, which enhances our understanding of the management of reverse exchanges and resource dependencies in SSCs.

The relationship between high-sensitivity CRP and polyclonal Free Light Chains as markers of inflammation in chronic disease

Introduction: Serum concentrations of polyclonal free light chains (FLC) represent the activity of the adaptive immune system. This study assessed the relationship between polyclonal FLC and the established marker of innate immunity, C-reactive protein (CRP), in chronic and acute disease. Methods: We utilized four cross-sectional chronic disease patient cohorts: chronic kidney disease (CKD), diabetes, vasculitis and kidney transplantation; and a longitudinal intensive care case series to assess the kinetics of production in acute disease. Results: There was a weak association between polyclonal FLC and high-sensitivity CRP (hs-CRP) in the study cohorts. A longitudinal assessment in acute disease showed a gradual increase in FLC concentrations over time, often when CRP levels were falling, demonstrating clear differences in the response kinetics of CRP and FLC in this setting. Conclusion: Polyclonal FLC and hs-CRP provide independent information as to inflammatory status. Prospective studies are now required to assess the utility of hs-CRP and polyclonal FLC in combination for risk stratification in disease populations. © 2013 John Wiley & Sons Ltd.

Designing post-disaster supply chains:learning from housing reconstruction projects

Post-disaster housing reconstruction projects face several challenges. Resources and material supplies are often scarce; several and different types of organizations are involved, while projects must be completed as quickly as possible to foster recovery. Within this context, the chapter aims to increase the understanding of relief supply chain design in reconstruction. In addition, the chapter is introducing a community based and beneficiary perspective to relief supply chains by evaluating the implications of local components for supply chain design in reconstruction. This is achieved through the means of secondary data analysis based on the evaluation reports of two major housing reconstruction projects that took place in Europe the last decade. A comparative analysis of the organizational designs of these projects highlights the ways in which users can be involved. The performance of reconstruction supply chains seems to depend to a large extent on the way beneficiaries are integrated in supply chain design impacting positively on the effectiveness of reconstruction supply chains.

Perceived risks in cross-border transactions in agri-food chains

Nowadays, agri-food chains are more global than ever and are characterized by increased imports and exports and global sourcing of products, resulting in increased cross-border transaction risks. The objective of this paper is to identify the typical risks regarding agri-food supply chains involved in cross-border transactions and to assess their importance as perceived by agri-food managers. The analysis takes into consideration four different agrifood value chains (meat, grain, olive oil, fresh vegetables and fruits). Following an explorative approach and a qualitative technique, a series of face to face in-depth interviews was conducted. Results indicate that risk perception may be quite different across countries, value chains, tiers of the supply chain, as well as across respondents. The prevalence of Market dynamics risks was pointed out in most of the interviews, yielding the impression that many operators identify the market as the most difficult environment. Differences in risk perception between fresh produce (fruit/vegetables and meat) and processed food chains (grain and olive oil) are probably interrelated to the different degree of integration within these supply chains, the different level of standardization achieved and the different causes of risks that are inherent to the nature of the product.

Study of synchronisation in chains of coupled non-linear oscillators and resonators

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A non-linear encoder using a binary counterfor pulse-code modulation

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Logistical framework for last mile relief distribution in humanitarian supply chains:considerations from the field

Recent years large scale natural disasters: (e.g. 2004 Tsunami, 2005 Earthquake in South Asia, 2010 Earthquake in Haiti, 2010 flood in Pakistan, 2011 Earthquake in Japan etc.) have captured international attention and led to the advance of research of disaster management. To cope with these huge impact disasters, the involved stakeholders have to learn how quickly and efficiently the relief organisations are able to respond. After a disaster strikes, it is necessary to get the relief aid to the affected people by the prompt action of relief organisations. This supply chain process has to be very fast and efficient. The purpose of this paper is to define the last mile relief distribution in humanitarian supply chain and develop a logistical framework by identifying the factors that affect this process. Seventeen interviews were conducted with field officers and the data analysed to identify which are the critical factors for last mile relief distribution of disaster relief operation. A framework is presented classifying these factors according to the ability to implement them in an optimisation model of humanitarian logistics.