Some kinetic and equilibrium studies of σ-adduct formation and proton transfer in the reactions of aromatic nitro-compounds with bases

Comparison of kinetic and equilibrium data for the cyclisation of 1-(2,2-dimethyl-3-hydroxypropoxy)-2,4-dinitro- naphthalene in alkaline media with those for the cyclisation of 1-(3-hydroxypropoxy)-2,4-dinitronaphthalene indicates the absence of a marked gem-dimethyl effect. (^1)H n.m.r. and visible spectral measurements show that alkoxide addition to 2,2’4,4’,6,6’-hexanitrobibenzyl (HNBB) and 2,2’,4,4’,6,6’-hexanitrostilbene (HNS) gives σ-adducts. Formation of the 3-(3’-) adduct is kinetically preferred but the 1-(1’-) adduct is thermodynamically more stable. In media of high basicity the 1:2 adduct with alkoxide addition at the 1- and 1’- positions is observed. For HNS a third interaction occurs which may be alkoxide addition at the olefinic bond. Kinetic and equilibrium data are reported for the reactions with methoxide ions in methanol and ethoxide ions in ethanol and compared with data for related compounds. The interactions of aliphatic amines with 2,4,6-trinitro- benzyl chloride (TNBCl), HNBB, HNS and 2,4,6-trinitrophenetole (TNP) in dimethyl sulphoxide have been investigated using visible and (^1)H n.m.r. spectroscopic methods. Kinetic and equilibrium data are reported for the various processes observed. The reversible reactions of TNBCl with primary amines are found to be: rapid formation of the 3-adduct, followed by isomerisation to the thermodynamically more stable 1-adduct, followed by equilibration with the conjugate base formed by transfer of a side-chain proton. With the secondary amines piperidine and pyrrolidine, σ-adduct formation at the 1-position is not observed because the presence of two bulky groups at the 1-position is sterically unfavourable. The σ-adduct forming reactions occur via zwitterionic intermediates and it is shown that proton transfers between these species and amines may be kinetically significant. The reactions of HNBB and HNS with amine also involve the initial formation of 3-adducts and 1-adducts. At high amine concentrations di-adducts may be formed by reaction of the 1- and 1’- or 3- and 3’- positions. A slow reaction of HNBB with amines gives a blue species which is shown to be a dianion formed by loss of two methylene protons. The slow step-in this reaction is shown to be rate limiting proton transfer from the substrate or from l:lσ-adducts. TNP reacts with primary and secondary amines to give isomeric σ-adducts at the 3-position and 1-position. Nucleophilic substitution involves general acid catalysed expulsion of the ethoxy group and yields N-substituted picramides. Data are also reported for the reactions of TNBCl with hydroxide ions in water and 30:70 (v/v) DMSO-water, of TNBCl with hydroxide ions in mixed (methanol-water-tetrahydrofuran) solvents, of HNBB with sulphite ions and of 1,3,5-trinitrobenzene with thioglycollic acid in water

Territorialising movement: the politics of land occupation in Bangladesh

This paper considers the politics of land occupation in Bangladesh. Contentious politics have been conceptualised as 'societies in movement' by Raul Zibechi, defined through their attempts to disperse power through the reconfiguration of social relations between peasants, the state and capital. Drawing on the author's ethnographic engagement with peasant farmer movements in Bangladesh since 2002, the paper analyses the differential powers generated in, by and through the production of relations and connections involved in land occupations. This requires a consideration of both relational and structural understandings of contentious politics. Organisational structures and dynamics, as well as the 'resourcefulness' of social movements (e.g. their capacities to deploy material resources, skills and knowledges), enable land occupation since these are crucial in creating and maintaining the socio-material relations necessary for political activity to be prosecuted. Drawing together these insights, the paper conceptualises land occupation as a process of 'territorialising movement' articulated through three interwoven spatial practices: strategic occupation, reconfiguration of social relations and territorialisation of translocal solidarities

Preparing to work in level 2 BIM: an innovative approach to a training and educational need

The well-known (probably the best known) objective of the UK Government’s 2011 Construction Strategy was for ‘fully collaborative 3D BIM (with all project and asset information, documentation and data being electronic) as a minimum by 2016’. This deadline has passed, and a number of reports have followed, commenting on how far the construction industry has progressed in its response. It is clear that some organisations consider themselves to be well-advanced in terms of their digital capabilities, whilst others lag behind. What should be remembered though, is that meeting this objective is not only about the software capabilities of individuals and their firms, but about BIM collaboration within projects. The paper outlines an innovative training offering that prepares project teams for working in such an environment. Virtual Project is a structured 3-day course that offers, to senior and middle management, the experience of multi-disciplinary collaboration, exploring as the ‘8 pillars’ of guidance for working at Level 2 BIM and experiencing some of the available technology for the design, construction and operation of built assets. Case studies are presented that illustrate the development of Virtual Project and responses from the participants, and the outcomes are mapped against the UK Government’s Learning Outcomes Framework, as well as the published work of the BIM Academic Forum. There are reflections on the challenges encountered, such as running the course overseas, and opportunities, such as its delivery in an e-learning environment

Resourcing Scholar-Activism: Collaboration, Transformation, and the Production of Knowledge

In this article we offer a set of resources for scholar-activists to reflect on and guide their practice. We begin by suggesting that research questions should be triangulated to consider not only their scholarly merit but the intellectual and political projects the findings will advance and the research questions of interest to community and social movement collaborators

Situated solidarities and the practice of scholar-activism

Drawing on an analysis of an ongoing collaboration with rural peasant movements in Bangladesh, we explore the possibility of forging solidarity through practices of scholar-activism. In so doing, we consider the practice of reflexivity, reconsider forms of solidarity, and draw on the concept of convergence spaces as a way to envision sites of possibility. We mobilize the notion of situated solidarities to propose an alternative form of reflexive practice in scholarship. We then posit that there are six ‘practices’ that provide a useful schematic for thinking through the opportunities for the construction of these solidaritie

Substituent effects on fluoride binding by lanthanide complexes of DOTA-tetraamides

Fluoride binding by a series of europium and ytterbium complexes of DOTA-tetraamide ligands derived from primary, secondary and tertiary amides has been studied by NMR and luminescence spectroscopies. In all the systems studied, fluoride binding results in a change in the nature of the magnetic anisotropy at the metal centre from an easy axis, to an easy plane anisotropy. This results in reversal of the peaks in the NMR spectra, and in changes to the fine structure of the luminescence spectra. Furthermore, changes to the periphery of the binding cavity are implicated in determining the affinity constant for fluoride. There are clear differences in the entropic contribution to the free energy of activation between systems with benzylic amides and those with methylamides

Does the Clearance of Inhaled (99m)Tc-Sestamibi Correlate with Multidrug Resistance Protein 1 Expression in the Human Lung?

Purpose To examine the relation between the lung elimination rate of inhaled technetium 99m ((99m)Tc)-sestamibi and immunohistochemical expression of bronchopulmonary multidrug resistance protein 1 (MRP1) and permeability glycoprotein (P-gp) and assess the repeatability of the inhaled (99m)Tc-sestamibi clearance technique. Materials and Methods (99m)Tc-sestamibi is a known substrate for P-gp and MRP1, which are established cellular drug efflux transporters. The elimination rate of (99m)Tc-sestamibi from the lungs after inhalation as an aerosol has been hypothesized to be regulated by expression of these transporters. Institutional ethics committee approval was received for this prospective study. Written informed consent was obtained from all participants. The clearance of inhaled (99m)Tc-sestamibi from the lungs of 13 patients due to undergo surgery for primary lung cancer (five of 13) or spontaneous pneumothorax (eight of 13) was estimated after dynamic imaging of the lungs during a period of 40 minutes. The time taken to clear 50% of inhaled sestamibi (T1/2) was compared with a semiquantitative immunohistochemical assessment (grade 0-3) of MRP1 and P-gp expression in the lung by using parametric and nonparametric tests. The study was repeated in five participants to assess the repeatability of the technique by using a Bland Altman analysis method. Results MRP1 expression was seen in 12 of 13 patients, while P-gp expression was seen in only two. The mean (99m)Tc-sestamibi elimination rate was faster in patients (n = 6) with low levels of MRP1 expression (grade 0-1) and mean T1/2 of 105 minutes ± 20 (standard deviation), compared with those with higher levels of MRP1 expression (grade 2-3, n = 7) and mean T1/2 of 149 minutes ± 28 (P = .008). Bland-Altman analysis revealed excellent agreement between test and retest values. Conclusion Inhaled (99m)Tc-sestamibi clearance study is a repeatable technique demonstrating significant correlation with MRP1 expression in the lungs. (©) RSNA, 2016.</p

Stable Carbon and Nitrogen Isotope Variability of Bone Collagen to Determine the Number of Isotopically Distinct Specimens

Archaeological and palaeontological excavations frequently produce large quantities of highly fragmentary bone. These bones can help to answer questions regarding past environments and human and animal lifeways via a number of analytical techniques but this potential is limited by the inability to distinguish individual animals and generate sufficiently large samples. Using stable carbon and nitrogen isotope values of bone collagen (δ13C, δ15N), we present a metric to identify the number of isotopically distinct specimens (NIDS) from highly fragmented faunal assemblages. We quantified the amount of intra-individual isotopic variation by generating isotopic data from multiple elements from individual animals representing a wide variety of taxa as well as multiple samples from the same skeletal element. The mean intra-individual variation (inter-bone) was 0.52‰ (σ = 0.45) (Euclidean distance between two points in isotopic bivariate space), while the mean intra-bone variation was 0.63‰ (σ = 0.06). Using archaeological data consisting of large numbers of individual taxa from single sites, the mean inter-individual isotopic variation was 1.45‰ (σ = 1.15). We suggest the use of 1.50‰ in bivariate (δ13C, δ15N) space as a metric to distinguish NIDS. Blind tests of modelled archaeological datasets of different size and isotopic variability resulted in a rate of misclassification (two or more elements from the same individual being classified as coming from different individuals) of < 5%