A new thermo-desorption laser-heating setup for studying noble gas diffusion and release from materials at high temperatures.

A new heating and gas treatment line for Thermo-Desorption Spectrometry (TDS) of noble gases (He, Ne, Ar, Kr, and Xe) is presented. It was built with the primary objective to offer advanced temperature controls and capabilities while working in a cold environment. By choosing a high-power continuous wave laser as the heating source and using a proportional-integral-derivative controller system, TDS of noble gases can now be performed with fast and highly steady heating ramps (e.g., less than 1 °C deviation from the set point for ≤1 °C s-1 ramps). Sample temperature over 2000 °C can also routinely be reached, with limited heating of the sample support and the sample chamber, offering the possibility to have several samples awaiting in the ultra-high vacuum chamber. We also present the development efforts made to increase temperature homogeneity of the heated sample while limiting the contact with the sample holder. Recent results acquired with this TDS setup on krypton thermal diffusion in uranium dioxide (UO2) as a function of O2 additions are also presented as an application example.

Psychophysical estimate of plantar vibration sensitivity brings additional information to the detection threshold in young and elderly subjects.

OBJECTIVE: Vibration detection threshold of the foot sole was compared to the psychophysical estimate of vibration in a wide range of amplitudes in young (20-34 years old) and elderly subjects (53-67 years old). METHODS: The vibration detection threshold was determined on the hallux, 5th metatarsal head, and heel at frequencies of 25, 50 and 150 Hz. For vibrations of higher amplitude (reaching 360 µm), the Stevens power function (Ψ = k * Φn ) allowed to obtain regression equations between the vibration estimate (Ψ) and its physical magnitude (Φ), the n coefficient giving the subjective intensity in vibration perception. We searched for age-related changes in the vibration perception by the foot sole. RESULTS: In all participants, higher n values were measured at vibration frequencies of 150 Hz and, compared to the young adults the elderly had lower n values measured at this frequency. Only in the young participants, the vibration detection threshold was lowered at 150 Hz. CONCLUSION: The psychophysical estimate brings further information than the vibration detection threshold which is less affected by age. SIGNIFICANCE: The clinical interest of psychophysical vibration estimate was assessed in a patient with a unilateral alteration of foot sensitivity.

Exposure to anticholinergic and sedative drugs, risk of falls, and mortality: an elderly inpatient, multicenter cohort.

This study aimed to assess whether exposure to anticholinergic and sedative medications and its evolution was associated with increased risk of in-hospital falls and all-cause mortality. Furthermore, results were compared with 2 definitions of drug burden index (DBI) against the outcomes.This observational, multicentric, and longitudinal study was conducted among patients aged 65 years or older, in 3 geriatric hospitals, in Francheville, Lyon, and Villeurbanne, France (duration of follow-up, 11.6 months). The exposure to anticholinergic and sedative medications was quantified using a DBI, at admission and at the end of observation for 337 patients. The evolution of exposure was the absolute difference between the index at admission and at the end of observation. The outcomes were in-hospital falls and all-cause mortality.Overall, 5.9% of patients experienced a fall. The risk of fall was nearly 3-fold in patients whose DBI increased during hospital stay compared to those with stable or decreased DBI (hazard ratio, 2.9 [1.14-7.12]; P = 0.03), after adjustment for comorbidities.The overall proportion of mortality was 6.5%. The evolution of DBI during hospital stay was not related to the risk of mortality (hazard ratio, 1.9 [0.8-4.4]; P = 0.14). Results were similar with the 2 definitions of DBI.Increased exposure to anticholinergic and sedative medications during hospital stay is associated with a higher risk of in-hospital falls but not with mortality. The DBI could be implemented in hospital, to guide prescription and reduce anticholinergic and sedative drug exposure.