Reduced default mode network connectivity relative to white matter integrity is associated with poor cognitive outcomes in patients with idiopathic normal pressure hydrocephalus.

BACKGROUND: The aim of this study was to investigate whether default mode network (DMN) connectivity and brain white matter integrity at baseline were associated with severe cognitive impairments at baseline and poor cognitive outcomes after shunt placement in patients with idiopathic normal pressure hydrocephalus (iNPH). METHODS: Twenty consecutive patients with iNPH whose symptoms were followed for 6 months after shunt placement and 10 healthy controls (HCs) were enrolled. DMN connectivity and brain white matter integrity at baseline in the patients with iNPH and HCs were detected by using resting-state functional magnetic resonance imaging (MRI) with independent component analysis and diffusion tensor imaging, respectively, and these MRI indexes were compared between the patients with iNPH and HCs. Performance on neuropsychological tests for memory and executive function and on the gait test was assessed in the patients with iNPH at baseline and 6 months after shunt placement. We divided the patients with iNPH into the relatively preserved and reduced DMN connectivity groups using the MRI indexes for DMN connectivity and brain white matter integrity, and the clinical measures were compared between the relatively preserved and reduced DMN connectivity groups. RESULTS: Mean DMN connectivity in the iNPH group was significantly lower than that in the HC group and was significantly positively correlated with Rey auditory verbal learning test (RAVLT) immediate recall scores and frontal assessment battery (FAB) scores. Mean fractional anisotropy of the whole-brain white matter skeleton in the iNPH group was significantly lower than that in the HC group. The reduced DMN connectivity group showed significantly worse performance on the RAVLT at baseline and significantly worse improvement in the RAVLT immediate recall and recognition scores and the FAB scores than the preserved DMN connectivity group. Moreover, the RAVLT recognition score highly discriminated patients with relatively preserved DMN connectivity from those with relatively reduced DMN connectivity. CONCLUSIONS: Our findings indicated that iNPH patients with reduced DMN connectivity relative to the severity of brain white matter disruption have severe memory deficits at baseline and poorer cognitive outcomes after shunt placement. However, further larger-scale studies are needed to confirm these findings.

Charge reorganization energy and small polaron binding energy of rubrene thin films by ultraviolet photoelectron spectroscopy.

The hole­phonon coupling of a rubrene monolayer on graphite is measured by means of angle resolved ultraviolet photoelectron spectroscopy. Thus, the charge reorganization energy λ and the small polaron binding energy is determined, which allows insight into the nature of charge transport in condensed rubrene.

Studies toward the total synthesis of gambieric acids, potent antifungal polycyclic ethers: convergent synthesis of the CDEFG-ring system.

[reaction: see text] A convergent synthetic route to the CDEFG-ring system of gambieric acids, potent antifungal polycyclic ether marine natural products, has been developed. The present synthesis features convergent union of the CD- and G-rings through esterification, formation of the E-ring as a lactone form, stereoselective allylation to set the C26 stereocenter, and ring-closing metathesis reaction to construct the nine-membered F-ring.