Metal complexes of selected organic ligands containing sulphur and phosphorus

An industrial problem concerning a pesticide product, ®Tinox, lead to the work described in this thesis. This included the study of the chelating properties of six sulphur and oxygen ligands and five phosphoryl sulphur and oxygen ligands with nickel(ll) and coba lt(ll) halides. Thirty two complexes of nickel(II) and cobalt(ll) halides were prepared and are reported in this thesis. The ligands used in the investigation are 1. 3-thiabutanol 2. 1-mereapto-3-thiabutane 3. 1-mereapto-2-methoxyethane 4. l-methoxy-3-thiabutane 5. Di-(2-inethylthioethyl) disulphide 6. Di-(2-methoxyethyl) disulphide 7. 0,0-dimethyl methyl phosphorodithioate 8. 0 0, 0-dimethyl (2-methylthioethyl) phosphorodithioate 9. 0,0-dimethyl 0-(2-methylthioethyl) phosphorothionate 10. 0,0-dimethyl S-(2-methylthioethyl) phosphorothiolate 11. 0,0-dimethyl (2-methylthioethyl) thiophosphonate The complexes were investigated by magnetic, spectrophotometric (infrared, ultraviolet) and conductiometric measurements. The stereochemistry of the complexes prepared depended on the particular ligand used and examples of octahedral tetrahedral and square planar complexes of nickel (ll) halites and tetrahedral and square planar of cobalt halides complexes were obtained. A comparison between the co-ordinating properties of sulphur and oxygen in their analogout forms i.e. thiol with hydroxyl, thioether with ether and thiophosphate with phosphate was made. A preliminary study on the use of ferric salt in the stablisation of ®Tinox was conducted. No conclusion could be established at this stage and further experimental work is required for a proper evaluation on the potential use of the ferric salt

Diabetic Glomerulosclerosis

Why should the mesangial cells be irritated? We recently observed in some diabetics black deposits beneath and on both sides of the basement membrane. These appear quite similar to deposits seen in and around the basement membrane in glomerulonephritis and in lupus nephritis. I do not know for sure what they are, but theory says that in glomerulonephritis they probably represent antigen-antibody complexes. There is some evidence to support this. One would assume that in diabetes they might be the same thing. Or they might be some other atypical plasma protein which results from the abnormal pattern of diabetic metabolism. I do not know. I believe this substance may be trapped by the basement membrane. It may be an abnormal substance that is trapped, or it may be an abnormal basement membrane that traps it. As this material is trapped, it is irritating to the mesangial cells and causes them to proliferate and secrete more of the basement membrane-like material. This material gradually fills up the glomeruli, and causes them to become non-functional, ultimately leading to uremia and death. It is of great interest also that these same processes are observed in experimentally-produced diabetes in the dog, a non-hereditary form of diabetes. This would seem to favor a metabolic rather than a genetic origin for the vascular defect

Diabetic Microangiopathy

Microangiopathy is the term applied to the abnormal state of the capillaries, arterioles, and venules found in the diabetic patient. It is characterized principally by thickening of the basement membrane of these small vessels. It might be worth mentioning that while we are concerned here with the smaller blood vessels, diabetic patients also show thickening of the basement membrane beneath the endothelium of arteries of all sizes. Also, the basement membrane-like material that surrounds each smooth muscle fiber in the wall of arteries shows similar thickening in diabetic patients. With this thickening, there is an increased glycoprotein content of the arterial wall. Diabetic microangiopathy is associated with well known clinical disturbances in the retina and in the kidney, but involves as well capillaries throughout the body

Surface and subsurface structural response on the City of London cable tunnels project

This paper presents surface and subsurface ground and structural response to the excavation of an urban cable tunnel within London clay and the Lambeth Group strata. Project specific tunnelling volume losses were estimated and found to be dependent on face advance and geology. The presence of adjacent buildings reduced predicted ?greenfield? settlements. The tunnel passed below a continuous section comprising basements, box rail tunnels and other structures. These structures generally responded at the level of their foundations. The presence of a pile group through which the tunnel passed only reduced surface settlement by ~50%. Passing below two existing segmentally-lined LUL tunnels these responded immediately and as predicted, although with somewhat increased trough widths indicating a stiffening effect. A multi-span bridge directly above the LUL tunnels on deep pier foundations, part of the Holborn Viaduct, settled more slowly and twice as much as anticipated. A possible general effect of tunnelling on heavily loaded foundations including end-bearing piles is discussed

Aluminium content of spanish infant formula

Aluminium toxicity has been relatively well documented in infants with impaired renal function and premature neonates. The aims of this study were to analyse the concentration of aluminium in the majority of infant formulae sold commercially in Spain, to determine the influence of aluminium content in the tap water in reconstituted powder formulae and to estimate the theoretical toxic aluminium intake in comparison with the PTWI, and lastly, to discuss the possible interactions of certain essential trace elements added to formulation with aluminium according to type or main protein based infant formula. A total of 82 different infant formulae from 9 different manufacturers were studied. Sample digestion was simulated in a closed acid-decomposition microwave system. Aluminium concentration was determined by atomic absorption spectrophotometry with graphite furnace. In general, the infant formulae studied provide an aluminium level higher than that found in human milk, especially in the case of soya, preterm or hydrolysed casein-based formulae. Standard formulae provide lower aluminium intakes amounting to about 4 % PTWI. Specialised and preterm formulae result in moderate intake (11 – 12 % and 8 – 10 % PTWI, respectively). Soya formulae contribute the highest intake (15 % PTWI). Aluminium exposure from drinking water used for powder formula reconstitution is not considered a clear potential risk. In accordance with the present state of knowledge about aluminium toxicity, it seems prudent to call for continued efforts to standardise routine quality control and reduce aluminium levels in infant formula as well as to keep the aluminium concentration under 300 g l-1 for all infant formulae, most specifically those formulae for premature and low birth neonates

Centrality dependence of the expansion dynamics in Pb-Pb collisions at 158 A GeV/c

Two-particle correlation functions of negatively charged hadrons from Pb-Pb collisions at 158 GeV/c per nucleon have been measured by the WA97 experiment at the CERN SPS. A Coulomb correction procedure that assumes an expanding source has been implemented. Within the framework of an expanding thermalized source model the size and dynamical state of the collision fireball at freeze-out have been reconstructed as a function of the centrality of the collision. Less central collisions exhibit a different dynamics than central ones: both transverse and longitudinal expansion velocities are slower, the expansion duration is shorter and the system freezes out showing smaller dimensions and higher temperature.Comment: 22 pages, 11 figures, Te

New results from the NA57 experiment

We report results from the experiment NA57 at CERN SPS on hyperon production at midrapidity in Pb-Pb collisions at 158 $A$ GeV/$c$ and 40 $A$ GeV/$c$. $\Lambda$, $\Xi$ and $\Omega$ yields are compared with those from the STAR experiment at the higher energy of the BNL RHIC. $\Lambda$, $\Xi$, $\Omega$\ and preliminary $K_S^0$ transverse mass spectra are presented and interpreted within the framework of a hydro-dynamical blast wave model.Comment: 8 pages, 3 figures, contribution to the proceedings of The XXXVIIIth Rencontres de Moriond "QCD and High Energy Hadronic Interactions

Expansion dynamics of Pb-Pb collisions at 40 A GeV/c viewed by negatively charged hadrons

In this paper we present results on transverse mass spectra and Hanbury-Brown and Twiss correlation functions of negatively charged hadrons, which are expected to be mostly negative pions, measured in Pb-Pb collisions at 40 A GeV/c beam momentum. Based on these data, the collision dynamics and the space-time extent of the system at the thermal freeze-out are studied over a centrality range corresponding to the most central 53% of the Pb--Pb inelastic cross section. Comparisons with freeze-out conditions of strange particles and HBT results from other experiments are discussed.Comment: 29 pages, 18 figure