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This work reports on the new chemical dosimeters for UV radiation dose measurements on coral reefs and in seawater. The proposed dosimeters can measure the actual dose of UV radiation, which consists of 95% UVA and 5% UVB radiation, unlike the currently-used radiometers in marine and ocean waters that measure the dose of UVA and UVB radiation separately. The dosimeters are composed of water, poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) (Pluronic F-127) as a gel matrix, and 2,3,5-triphenyltetrazolium chloride (TTC) as a UV radiation-sensitive compound. In the work, the dosimeters were characterised in terms of their response to the dose of UV radiation depending on the TTC concentration and the irradiation and storage conditions of the dosimeters. The stability of the dosimeters over time was also examined. The obtained results indicate that the TTC-Pluronic F-127 dosimeters can be used to measure absorbed doses of UV radiation in the saltwater environment. The developed dosimeters with a concentration of 0.1% TTC can be used up to 5 J/cm2, which predisposes them to UV radiation measurements at a depth of more than 10 m in sea and ocean waters in 10-min intervals during all months throughout the year. [ABSTRACT FROM AUTHOR]

In this work, a method for the measurement of one-dimensional (1D) UV radiation dose is described. It comprises a new tablet dosimeter that measures the dose using reflectance spectrophotometry. The tablet dosimeter elaborated is a solid structure with a cylindrical form and has been manufactured with polycaprolactone (PCL) doped with a representative of tetrazolium salts: 2,3,5−triphenyltetrazolium chloride (TTC). The PCL used makes the dosimeter biodegradable and therefore proecological. The TTC dopant is distributed uniformly in the whole PCL tablet, and the whole tablet changes color to red under UVC irradiation. The intensity of this color increases if the PCL–TTC tablet absorbs higher doses. The color of the tablet is stable for at least 30 days after irradiation. It is proposed that the PCL-TTC tablet be used for measurement with reflectance spectrophotometry in order to determine the reflectance of light versus the absorbed dose in a fast and easy manner. On this basis, the PCL-TTC tablet could be characterized by providing information on its dose range, which amounted to 0–2 J/cm2. Moreover, other parameters were derived, such as dose sensitivity, quasilinear dose range, and dose threshold. The morphology of the tablets studied using scanning electron microscopy revealed their high porosity, which however did not influence the reflectance measurements with the aid of the chosen instrument. UVC irradiation at a dose (15 J/cm2) much above the PCL-TTC tablets' dose range did not alter the morphology of the tablets. The PCL-TTC tablet read with reflectance spectrophotometry is shown to be a promising and fast method for 1D UV dose measurements. [ABSTRACT FROM AUTHOR]

[Display omitted] • A new elastic radiochromic TTC–PVA dosimeter for UV radiation measurements is presented. • The dosimeter is characterised in terms of dose response, stability, and repeatability. • A proposal for the personal use of a dosimeter is presented. This work presents a new personal chemical gel dosimeter containing a radiation-sensitive 2,3,5-triphenyltetrazolium chloride embedded in a poly(vinyl alcohol) matrix for UV radiation measurements. The dosimeter changes colour from colourless to pink under the influence of UV radiation, and colour intensity increases with increasing absorbed dose. The dosimeter was characterised using reflectance spectrophotometry for stability, repeatability, and dose–response, including dose sensitivity, threshold dose, as well as linear and dynamic dose range. The TTC–PVA dosimeter can be used to measure UVA, UVB, and UVC radiation, as well as actual solar radiation consisting of UVA and UVB radiation. As a result, it is promising for use as a personal dosimeter for people exposed to UV radiation from artificial and natural sources. The comfort of using the dosimeter would be ensured by its flexibility, which allows it to be properly adjusted to the curvatures of the human body. [ABSTRACT FROM AUTHOR]

Abstract: The fabrication and the characterization results of a triple-layer organic light emitting diode (OLED) using a fluorinated Eu3+-β-diketone complex particularly sensitive to UV radiation are presented. The electroluminescence spectra of the devices, fabricated by thermo evaporation carried out in a high vacuum environment, present narrow emission bands characteristics of the Eu3+ ion. The intensity of these peaks decrease as a function of the UV radiation impinging on the device, and is strongly dependent from the UV radiation cumulative dose. The results show that measuring the main Eu3+ emission intensity it is possible to fabricate a portable UV personal dosimeter using this kind of complexes as emitting layer in an OLED device. The OLED emission will be inversely proportional to the UV irradiation exposure. [Copyright &y& Elsevier]

Abstract: A novel UV dosimeter is described comprising a tetrazolium dye, neotetrazolium chloride (NTC), dissolved in a film of polymer, polyvinyl alcohol (PVA). The dosimeter is pale yellow/colourless in the absence of UV light, and turns red upon exposure to UV light. The spectral characteristics of a typical UV dosimeter film and the mechanism through which the colour change occurs are detailed. The NTC UV dosimeter films exhibit a response to UV light that is related to the intensity and duration of UV exposure, the level of dye present in the films and the thickness of the films themselves. The response of the dosimeter is temperature independent over the range 20–40°C and, like most UV dosimeters, exhibits a cosine-like response dependence upon irradiance angle. The introduction of a layer of a UV-screening compound which slows the rate at which the dosimeter responds to UVR enables the dosimeter response to be tailored to different UV doses. The possible use of these novel dosimeters to measure solar UV exposure dose is discussed. [Copyright &y& Elsevier]

A UV indicator/dosimeter based on benzyl viologen (BV2+) encapsulated in polyvinyl alcohol (PVA) is described. Upon exposure to UV light, the BV2+/PVA film turns a striking purple colour due to the formation of the cation radical, BV•+. The usual oxygen sensitivity of BV•+ is significantly reduced due to the very low oxygen permeability of the encapsulating polymer, PVA. Exposure of a typical BV2+/PVA film, for a set amount of time, to UVB light with different UV indices produces different levels of BV•+, as measured by the absorbance of the film at 550 nm. A plot of the change in absorbance at this wavelength, ΔAbs(550), as a function of UV index, UVI, produces a linear calibration curve which allows the film to be used as a UVB indicator, and a similar procedure could be employed to allow it to be used as a solar UVI indicator. A typical BV2+/PVA film generates a significant, semi-permanent (stable for >24 h) saturated purple colour (absorbance ~0.8–0.9) upon exposure to sunlight equivalent to a minimal erythemal dose associated with Caucasian skin, i.e. skin type II. The current drawbacks of the film and the possible future use of the BV2+/PVA film as a personal solar UV dosimeter for all skin types are briefly discussed. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Background/purpose: Skin cancer risk estimations are based on sun exposure data. However, the reliability of collected data in personal ultraviolet (UV) dosimeters studies has not previously been validated. We aimed at investigating the data reliability and subject compliance in a study of sun exposure behaviour among 407 subjects (age range, 4–68 years) during 54 943 days based on time-stamped personal UV dosimeter readings and diary records. Methods: By comparing diary records and UV dosimeter readings on a daily basis, we investigated subject compliance, total sun exposure record, reasons for non-responding along with rates of diary completing errors. Efforts to improve compliance were described. Results: The subject compliance rate was median 93.5% (percent days where the diary was completed and the UV dosimeter was worn). The total sun exposure record rate was median 84.1% (percent of participation days with both UV dosimeter and diary records and where the UV dosimeter was worn). Children, adolescents and golfers had lower sun exposure record rates than the rest of the groups ( P<0.05). No significant difference was found between males and females ( P=0.15). The 17 non-responders were 10 children, three adolescents, one sun worshipper, two golfers and one gardener. Correctable diary completing mistakes were found in 3.1% of the days. Children made more completing mistakes than adults ( P=0.001). The average estimated error rate was 3.3% and was higher for children (6.3%) and adolescents (3.6%) than the adult groups (2.4%). Conclusion: High subject compliance rate and data reliability were obtained because the investigators were service minded but persistent, offering dosimeter maintenance service within 24 h and scrutinized data for errors and mistakes. [ABSTRACT FROM AUTHOR]