A thermodynamic study of large tetraaza ligands and their Cu (II) complexes

Six macrocyclic (L1-L6) and ten non-cyclic (L7-L16) tetraaza ligands containing only secondary nitrogen atoms were synthesised and characterised. A further tetramine ligand (L17) with two primary and two secondary nitrogen atoms was obtained commercially. The stepwise protonation constants of all these ligands and the Cu(II) complex stability constants of all but three of the ligands (L10-L12) were determined by potentiometric titration. The Cu(II) complex formation enthalpies of L¬1¬-L9 and L13-L17 were determined using a batch microcalorimetric technique. The enthalpies of solution of L1-L17 were determined by isoperibolic calorimetry and the enthalpies of vaporisation of L1-L9, L16 and L17 determined using a custom built vapour pressure-weight loss apparatus. The data for the ligands L1-L17 and for a number of macrocyclic and noncyclic tetraaza and tetramine ligands with smaller macrocyclic and/or chelate ring sizes (L(I)-L(XVIII)) has been examined to determine the effect of increasing macrocyclic and/or chelate ring size on the thermodynamic properties described above, and to determine the thermodynamic origins of the macrocyclic effect, the observed increase in stability of a macrocyclic ligand relative to that of an analogous non-cyclic ligand, and to determine the effect of increasing ligand size on the macrocyclic effect. The enthalpy contribution to the macrocyclic effect has been shown to be equal to the difference between the hydration enthalpy of the free macrocyclic and non-cyclic ligands. Differences in complex hydration appear to be small. The entropy contribution appears to be due to the greater loss of conformational entropy of the non-cyclic ligand on copper complex formation. The magnitude of the macrocyclic effect appears to be independent of ligand size but is dependent on the non-cycllic ligand chosen as a model for the macrocyclic ligand

Notes on some distinctive points in the Pupae of West African mosquitos

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Guidelines for best practice in great ape tourism

Tourism based on the viewing of great apes is increasingly promoted as a means of generating revenue for range states, local communities, and the private sector (e.g. GRASP, 2006 ). This is despite known risks from tourism, including disease transmission, which have caused concern among conservationists and prompted the International Union for Conservation of Nature to publish guidelines on best practices for great ape tourism (Macfi e & Williamson, 2010 ). IUCN is one of the world's most respected authorities on species conservation, and brings together governments, UN agencies, and NGOs to conserve biodiversity and to ensure that any use of natural resources is equitable and ecologically sustainable

Accumulation of Cadmium in Near-Isogenic Lines of Durum Wheat (Triticum Turgidum L. Var Durum): the Role of Transpiration

Concentrations of cadmium in the grain of durum wheat (Triticum turgidum L. var durum) are often above the internationally acceptable limit of 0.2 mg kg−1. Cultivars that vary in concentrations of cadmium in the grain have been identified but the physiology behind differential accumulation has not been determined. Three pairs of near-isogenic lines (isolines) of durum wheat that vary in aboveground cadmium accumulation (8982-TL ‘high’ and ‘low’, W9260-BC ‘high’ and ‘low’, and W9261-BG ‘high’ and ‘low’) were used to test the hypothesis that the greater amounts of cadmium in shoots of the ‘high’ isolines are correlated with greater volumes of water transpired. In general, cadmium content was positively correlated with transpiration only in the ‘low’ isolines. Although shoots of the ‘high’ isolines of W9260-BC and W9261-BG contained higher concentrations of cadmium than did their corresponding ‘low’ isolines, they did not transpire larger volumes of water. In addition, isolines of 8982-TL transpired less water than did the other pairs of isolines yet both ‘high’ and ‘low’ isolines of 8982-TL contained higher amounts of cadmium than did the other pairs. The difference between ‘high’ and ‘low’ isolines appears to be related to the relative contribution of transpiration to cadmium translocation to the shoot. Increased transpiration was associated with increased cadmium content in the ‘low’ isolines but in the ‘high’ isolines increased cadmium in the shoot occurred independently of the volume of water transpired

A microfluidic chip based model for the study of full thickness human intestinal tissue using dual flow

© 2016 Author(s). The study of inflammatory bowel disease, including Ulcerative Colitis and Crohn's Disease, has relied largely upon the use of animal or cell culture models; neither of which can represent all aspects of the human pathophysiology. Presented herein is a dual flow microfluidic device which holds full thickness human intestinal tissue in a known orientation. The luminal and serosal sides are independently perfused ex vivo with nutrients with simultaneous waste removal for up to 72 h. The microfluidic device maintains the viability and integrity of the tissue as demonstrated through Haematoxylin & Eosin staining, immunohistochemistry and release of lactate dehydrogenase. In addition, the inflammatory state remains in the tissue after perfusion on the device as determined by measuring calprotectin levels. It is anticipated that this human model will be extremely useful for studying the biology and tes ting novel interventions in diseased tissue

Refeeding Syndrome: A Literature Review

Refeeding syndrome (RFS) describes the biochemical changes, clinical manifestations, and complications that can occur as a consequence of feeding a malnourished catabolic individual. RFS has been recognised in the literature for over fifty years and can result in serious harm and death. Crude estimates of incidence, morbidity, and mortality are available for specific populations. RFS can occur in any individual but more commonly occurs in at-risk populations. Increased awareness amongst healthcare professionals is likely to reduce morbidity and mortality. This review examines the physiology of RFS and describes the clinical manifestations. A management strategy is described. The importance of a multidisciplinary approach is emphasized

A critical evaluation of the electronic surgical logbook

BACKGROUND: The Association of Surgeons of Great Britain and Ireland (ASGBI) devised the electronic surgical logbook (version 2.4) for higher trainees in General Surgery enabling trainees to compile a uniform data set of their operative and training experience. This is in use by higher surgical trainees (HST) in the United Kingdom. This logbook permits trainees to submit data centrally into a Regional Analysis Database (RAD). With the implementation of the European Working Time Directive (EWTD) there is need for reliable data to assess the effects of the directive on training. In order to draw meaningful conclusions from the database the quality of data needs to be validated. We critically analysed the RAD in the Yorkshire region for a one-year period. METHODS: The RAD from the ASGBI for the Yorkshire region was analysed. Data for the period 01/10/2002–30/09/2003 was identified and interrogated using Microsoft Excel (2000 version). The RAD was compared with information obtained from the Regional Surgical Advisor for Yorkshire with respect to hospitals, surgical consultants and HST's in the region during the study period. RESULTS: There were 13,755 operations entered for the study period. 579 corrections to the data had to be made (4.2%) and a further 1140 entries were deleted (8.2%). Following corrections and deletions 12,615 operative entries were available for analysis. Overall 12.5% of the data required either correction or exclusion from the database prior to analysis. CONCLUSION: The RAD has a large dataset useful to monitor and assess training. However, the quality of the data needs to be verified prior to use. Recommendations have been made to develop the ASGBI logbook, which would eventually translate to improved data reliability of the RAD

Pb Distribution in Bones from the Franklin Expedition: Synchrotron X-Ray Fluorescence and Laser Ablation/Mass Spectroscopy

Synchrotron micro-X-ray Fluorescence has been used to map the metal distribution in selected bone fragments representative of remains associated with the Franklin expedition. In addition, laser ablation mass spectroscopy using a 25 μm diameter circular spot was employed to compare the Pb isotope distributions in small regions within the bone fragments. The X-ray Fluorescence mapping shows Pb to be widely distributed in the bone while the Pb isotope ratios obtained by laser ablation within small areas representative of bone with different Pb exchange rates do not show statistically significant differences. These results are inconsistent with the hypothesis that faulty solder seals in tinned meat were the principle source of Pb in the remains of the expedition personnel