Feasibility studies for assessing internal exposure to 233U

The potential internal occupational exposure encountered as a consequence of the 232Th-233U fuel cycle are likely to arise predominantly from the inhalation of 232Th, 233U and (232Th + 233U) compounds of absorption Types M and S. In the past, although direct and indirect methods for assessments of internal exposure to 232Th and its daughters were developed, standardised and employed, no such attempts have been made with regard to 233U and 233U + 232Th. Therefore, feasibility studies for assessing internal exposure to 233U have been conducted using three methods: urine bioassay, in vivo counting and measurement of thoron gas in the exhaled breath of a worker. This paper describes details of these studies and discusses the results obtained

Electronic transduction of proton translocations in nanoassembled lamellae of bacteriorhodopsin

An organic field-effect transistor (OFET) integrating bacteriorhodopsin (bR) nanoassembled lamellae is proposed for an in-depth study of the proton translocation processes occurring as the bioelectronic device is exposed either to light or to low concentrations of general anesthetic vapors. The study involves the morphological, structural, electrical, and spectroscopic characterizations necessary to assess the functional properties of the device as well as the bR biological activity once integrated into the functional biointerlayer (FBI)-OFET structure. The electronic transduction of the protons phototranslocation is shown as a current increase in the p-type channel only when the device is irradiated with photons known to trigger the bR photocycle, while Raman spectroscopy reveals an associated C=C isomer switch. Notably, higher energy photons bring the cis isomer back to its trans form, switching the proton pumping process off. The investigation is extended also to the study of a PM FBI-OFET exposed to volatile general anesthetics such as halothane. In this case an electronic current increase is seen upon exposure to low, clinically relevant, concentrations of anesthetics, while no evidence of isomer-switching is observed. The study of the direct electronic detection of the two different externally triggered proton translocation effects allows gathering insights into the underpinning of different bR molecular switching processes. © 2014 American Chemical Society