Construction of a Cerenkov light source.

A radiation source has been developed and implemented from Cerenkov emission that is intended to provide an intense continuum from the infrared to 600 A. Parasitic use of the primary electron beam at the Stanford Linear Accelerator Center (SLAC) together with a novel optical geometry for light collection can give a focused and tunable ultraviolet beam with 10(4) kW/m(2)sr brightness, 10(-2) spectral purity, and with the pulsed, 5 ps time structure of the SLAC electron beam. Measurements of emission characteristics in the visible part of the spectrum correlate closely with the predicted performance.

Neuroimaging in the diagnosis of frontotemporal dementia.

The role of neuroimaging for the diagnosis of frontotemporal dementia (FTD) remains controversial. The modern history of imaging in the study of FTD is outlined. Also, the findings on MRI and SPECT in 15 consecutive FTD patients is noted. Both MRI and SPECT detected focal frontal involvement in nearly every single case (MRI 14/15 and SPECT 15/15). Also, the majority of patients showed asymmetry on MRI (8/15) and SPECT (12/15). This study confirms that neuroimaging is sensitive to the frontotemporal degeneration associated with FTD. Additionally, it suggests that this is often asymmetric in the relative involvement of these brain regions.

Standardized scaling procedures for rating perceived exertion during resistance exercise.

The purpose of this project was to determine the validity of standardized Borg scale instructions and scale anchoring procedures to measure active muscle rating of perceived exertion and overall rating of perceived exertion during resistance exercise. Anchoring procedures were determined for each of 7 exercises before the completion of 2 counterbalanced experimental trials. In one trial, subjects lifted 90% of 1 repetition maximum (1RM) 5 times. In the other, subjects lifted 30% of 1RM 15 times. Adjusted R2 and SEMs were used to determine linearity of Borg 15-category scale responses with respect to repetitions at equal work increments for both the group and the sum of the individuals. Both group and individual responses had high adjusted R2 and low SEM values. These results suggest that the current scaling instructions used with the Borg 15-category scale are valid for use during resistance exercise.

Behavioral disorders in the frontal and temporal variants of frontotemporal dementia.

OBJECTIVE: To compare the behavioral features and to investigate the neuroanatomic correlates of behavioral dysfunction in anatomically defined temporal and frontal variants of frontotemporal dementia (tvFTD and fvFTD). METHODS: Volumetric measurements of the frontal, anterior temporal, ventromedial frontal cortical (VMFC), and amygdala regions were made in 51 patients with FTD and 20 normal control subjects, as well as 22 patients with Alzheimer disease (AD) who were used as dementia controls. FTD patients were classified as fvFTD or tvFTD based on the relative degree of frontal and anterior temporal volume loss compared with controls. Behavioral symptoms, cerebral volumes, and the relationship between them were examined across groups. RESULTS: Both variants of FTD showed significant increases in rates of elation, disinhibition, and aberrant motor behavior compared with AD. The fvFTD group also showed more anxiety, apathy, and eating disorders, and tvFTD showed a higher prevalence of sleep disturbances than AD. The only behaviors that differed significantly between fvFTD and tvFTD were apathy, greater in fvFTD, and sleep disorders, more frequent in tvFTD. FvFTD was associated with greater frontal atrophy and tvFTD was associated with more temporal and amygdala atrophy compared with AD, but both groups showed significant atrophy in the VMFC compared with AD, which was not associated with VMFC atrophy. In FTD, the presence of many of the behavioral disorders was associated with decreased volume in right-hemispheric regions. CONCLUSION: FvFTD and tvFTD show many similarities in behavior, which appear to be associated with damage to right frontal and temporal structures.