The synthesis and study of phosphine crown ether ligands, and an investigation of how the binding of sodium or potassium ions affects the donor ability of the phosphorus center

The phosphine crown ether, 16-(4'diphenylphosphinophenyl)-1,4,7,10,13-pentaoxa-16azacyclooctadecane (III), was synthesized using a reaction scheme beginning with n-phenyldiethanolamine and the dichloride of tetraethylene glycol, with an overall yield of 4%. Platinum and Palladium complexes of the ligand, of the form MC12L2, were synthesized as well. 13C NMR and picrate extraction data indicate III and IV (the crown-5 analog) both moderately bind sodium (14%, 15%) and potassium ions (17%, 28%). Compound V (a crown-5, triphenylphosphine-based ligand) will bind both sodium and potassium ions as well (18%, 6%). When IV is complexed to nickel carbonyl (Ni(CO)3), the addition of sodium and potassium ions cause the Al carbonyl stretching frequency to increase slightly (0.3 cm-1, 0.2 cm 1). For comparison, the addition of a proton causes the A1 carbonyl stretching frequency to increase 5.2 cm-1. However, the shift in the A1 carbonyl stretching frequency upon the addition of sodium or potassium ions indicates that ion binding by the crown ether is communicated to the phosphorus and finally to the carbonyl groups.Ball State UniversityMuncie, IN 47306Thesis (M.S.)Department of Chemistr

Considerations on long-term immuno-intervention in the treatment of multiple sclerosis: an expert opinion

INTRODUCTION As management of multiple sclerosis (MS) requires life-long treatment with disease-modifying agents, any risks associated with long-term use should be considered when evaluating therapeutic options. AREAS COVERED Immune cells of the innate and adaptive immune systems play various roles in the pathogenesis of MS. MS therapies affect the immune system, each with a unique mode of action, and consequently possess different long-term safety profiles. Rare, but serious safety concerns, including an increased risk of infection and cancer, have been associated with immunosuppressant use. The risks associated with newer immunosuppressive agents, which target specific elements of MS disease pathophysiology, are not yet fully established as the duration of clinical trials is relatively short and post-marketing experience is limited. Non-immunosuppressants used to treat MS have well-defined safety profiles established over a large number of patient-years demonstrating them to be well-tolerated long-term treatment options. When considering the long-term use of disease-modifying agents for treating MS, classification as immunosuppressants or non-immunosuppressants can be useful when evaluating potential risks associated with chronic use. EXPERT OPINION A successful therapeutic strategy for any serious, chronic disease such as MS should weigh effectiveness versus long-term safety of available treatments

Stroke-like encephalopathy in an infant with 3-hydroxy-3-methylglutaryl-coenzyme A lyase deficiency

A 2.5-year-old boy presented with acute metabolic decompensation in whom 3-hydroxy-3-methyl-glutaryl-coenzyme A (HMG-CoA) lyase deficiency was diagnosed. Four days after metabolic decompensation, a stroke-like encephalopathy with tonic clonic convulsion of the left arm and leg and coma developed. Brain oedema and subsequent demarcation and atrophy were observed mainly within the supply areas of the right anterior and middle cerebral artery and to a lesser extent in various sites within the right hemisphere. Residual neurological deficits included spastic paresis of the left arm and leg. and left supranuclear facial palsy and aphasia, indicating bilateral diffuse brain affection. CONCLUSION: In the presented patient with HMG-CoA lyase deficiency, stroke-like encephalopathy occurred days after metabolic decompensation indicating ongoing (intracerebral) metabolic derangement. Monitoring of the intracerebral accumulation of toxic metabolites by magnetic resonance spectroscopy and of cerebral haemodynamics might be useful for a better understanding of the pathogenetic mechanisms of stroke-like encephalopathy and to identify patients at ris

The International Research Group on Wood Preservation

Conventional preservatives used to protect wood from insect and microbial damages are presently of major concern to human health and the environment. Finding alternative and economical preservatives has not been successful. Previous studies have shown that the resinous material extracted from the guayule plant (Parthenium argentatum, Gray) has both insect- and microbial-resistant properties. Unfortunately, it has not been accepted commercially because of the lack of an adequate supply of the raw material. However, the potential domestication of the guayule plant to produce hypoallergenic rubber latex will result in the production of large amounts of waste wood material. This should provide opportunity to use this natural source of the biologically resistant resinous chemicals. The objective of this preliminary study was to determine the effects of the rubber latex-removed wood residues or bagasse and the resinous extracts on termite- and decay-resistant properties. Two types of test materials were used in the study. One was wood impregnated with organic-solvent extracted resinous material from the plant. The other was composite wood fabricated using the residue or whole plant and plastic binder, which was used to improve the physical properties of the composite. Accelerated laboratory tests were conducted to determine the resistance of the wood products against the Eastern subterranean termite and wood fungi (brown-rot). The wood and stem of the guayule plant, wood treated with the resinous extract, and particle and composite wood made from ground guayule exhibited termite and wood fungal resistance. KEY WORDS: Brown-rot, decay, durability, extractives, fungus, guayule, bagasse, particleboard, specific gravity, termite, thickness change, weight loss, wood comp..