23 research outputs found

    New insights into the genetic etiology of Alzheimer's disease and related dementias

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    Characterization of the genetic landscape of Alzheimer's disease (AD) and related dementias (ADD) provides a unique opportunity for a better understanding of the associated pathophysiological processes. We performed a two-stage genome-wide association study totaling 111,326 clinically diagnosed/'proxy' AD cases and 677,663 controls. We found 75 risk loci, of which 42 were new at the time of analysis. Pathway enrichment analyses confirmed the involvement of amyloid/tau pathways and highlighted microglia implication. Gene prioritization in the new loci identified 31 genes that were suggestive of new genetically associated processes, including the tumor necrosis factor alpha pathway through the linear ubiquitin chain assembly complex. We also built a new genetic risk score associated with the risk of future AD/dementia or progression from mild cognitive impairment to AD/dementia. The improvement in prediction led to a 1.6- to 1.9-fold increase in AD risk from the lowest to the highest decile, in addition to effects of age and the APOE ε4 allele

    MEASUREMENT OF ENERGY-LOSS FROM A HEMT STRUCTURE BY OBSERVING EMITTED PHONONS

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    Using nanosecond heat pulse techniques we have observed both acoustic and optic phonon emission by the hot 2DEG in GaAs/AlGaAs HEMT structures. Both transverse and longitudinal modes were detected in the optic regime but only transverse in the acoustic regime. The ability to vary carrier density allowed us to eliminate the effect of contact resistance and hence to determine absolutely the power level at which energy loss took place equally via acoustic and optic phonons. The figure obtained was 2.3 +/- 0.5 pW per electron, inconsistent with a model of acoustic emission based simply on deformation potential coupling, suggesting the presence of an additional source of inelastic scattering
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