Deoxygenative C-C Bond-Forming Processes via a Net Four-Electron Reductive Coupling.

The nickel-catalyzed coupling of enones or enals with alkynes in the presence of silane and titanium alkoxide reductants provides direct access to skipped diene products. The process involves a net four-electron reductive coupling and proceeds with deoxygenation of the starting enone or enal. A new class of well-defined nickel(0) precatalysts bearing an unhindered N-heterocyclic carbene ligand, which was developed in optimization of the process, is essential for the efficiency of the transformation. The strategy allows the high reactivity of α,ß-unsaturated carbonyl substrates to be utilized in couplings with simultaneous extrusion of the oxygen atom, thus enabling a traceless strategy for alkene installation.

Visual field changes after a rehabilitation intervention: vision restoration therapy.

BACKGROUND: The objective of this study was to determine the effect of a visual rehabilitation intervention on visual field defects in a US cohort. Vision Restoration Therapy (VRT) consists of a specific pattern of stimulation that is directed at the border of the blind field. METHODS: This retrospective study evaluated individuals with homonymous visual field defect from retrochiasmatic lesions treated with 6 modules of VRT. Suprathreshold visual field testing of the central 43x32 was obtained at baseline and after each module. The main outcome measures were the change in stimuli detection and the shift in the position of the border of the blind field. The impact of age, time from injury and type of visual field defect were analyzed. RESULTS: Among 161 patients, the mean absolute improvement in stimuli detection was 12.8%. The average border shift was 4.87. Improvements of > or =3% was noted in 76% of patients. Absolute change in stimulus detection of > or =3% at mid-therapy was associated with a greater final improvement. Age, time from lesion and type of visual field defect did not influence the degree of field expansion. CONCLUSIONS: VRT improves stimulus detection and results in a shift of the position of the border of the blind field as measured on suprathreshold visual field testing. These results support prior reports and support VRT as a useful rehabilitative intervention for a proportion of patients with visual field defects from retrochiasmatic lesions.