Spectroscopic and Electrochemical Studies of Optically Active Bipyridyl Complexes

The tris(2,2'-bipyridine) complexes of ruthenium(II) and osmium(II) have been synthesised and optically resolved. The singly, doubly and triply reduced complexes have been prepared electrochemically and their circular dichroism and luminescence spectra have been measured. Investigation of the absorption, circular dichroism and luminescence spectra of the complexes and their reduced analogues strongly suggest that the added electrons are localised on the individual bipyridine ligands of the complexes. Hence the complexes are best formulated as [M(bipy)n(bipy-)3-n](n-1)+, where M = Ru, Os and n = 0, 1, 2 and 3. In addition, a chemical reduction technique using lithium metal has been developed. This has enabled the infrared spectra of the triply reduced complexes to be measured. The triply reduced ruthenium complex has been found to racemise in dry acetonitrile but is optically stable in dimethylformamide. This has been attributed to a weakening of the ligand field of bipyridine when it is reduced to the anion. Lithium 2,2'-bipyridinyl has been synthesised and complexed with the chiral co-ordinating ligands (-)-sparteine and R and S-tetra-N,N,N',N'-methyl propane-1,2-diamine whereupon its circular dichroism spectra have been measured. The tris(2,2'-bipyridine)iridium(III) complex has been synthesised and optically resolved and its hitherto unknown circular dichroism spectrum has been measured. The complex has been chemically reduced and in addition to the triply reduced complex the quadruply reduced complex has also been synthesised and their absorption and circular dichroism spectra have been measured. Investigation of the circular dichroism spectra again suggest that the added electrons are localised on the individual bipyridine ligands of the complexes

Towards microbiome transplant as a therapy for periodontitis: an exploratory study of periodontitis microbial signature contrasted by oral health, caries and edentulism

published_or_final_versio

Serum neurofilament dynamics predicts neurodegeneration and clinical progression in presymptomatic Alzheimer's disease

Neurofilament light chain (NfL) is a promising fluid biomarker of disease progression for various cerebral proteopathies. Here we leverage the unique characteristics of the Dominantly Inherited Alzheimer Network and ultrasensitive immunoassay technology to demonstrate that NfL levels in the cerebrospinal fluid (n = 187) and serum (n = 405) are correlated with one another and are elevated at the presymptomatic stages of familial Alzheimer's disease. Longitudinal, within-person analysis of serum NfL dynamics (n = 196) confirmed this elevation and further revealed that the rate of change of serum NfL could discriminate mutation carriers from non-mutation carriers almost a decade earlier than cross-sectional absolute NfL levels (that is, 16.2 versus 6.8 years before the estimated symptom onset). Serum NfL rate of change peaked in participants converting from the presymptomatic to the symptomatic stage and was associated with cortical thinning assessed by magnetic resonance imaging, but less so with amyloid-β deposition or glucose metabolism (assessed by positron emission tomography). Serum NfL was predictive for both the rate of cortical thinning and cognitive changes assessed by the Mini-Mental State Examination and Logical Memory test. Thus, NfL dynamics in serum predict disease progression and brain neurodegeneration at the early presymptomatic stages of familial Alzheimer's disease, which supports its potential utility as a clinically useful biomarker

Tendon Driven Finger Actuation System

A humanoid robot includes a robotic hand having at least one finger. An actuation system for the robotic finger includes an actuator assembly which is supported by the robot and is spaced apart from the finger. A tendon extends from the actuator assembly to the at least one finger and ends in a tendon terminator. The actuator assembly is operable to actuate the tendon to move the tendon terminator and, thus, the finger