Hydrogen Production through Catalytic Water Splitting Using Liquid-Phase Plasma over Bismuth Ferrite Catalyst

This study examined the H2 production characteristics from a decomposition reaction using liquid-phase plasma with a bismuth ferrite catalyst. The catalyst was prepared using a sol–gel reaction method. The physicochemical and optical properties of bismuth ferrite were analyzed. H2 production was carried out from a distilled water and aqueous methanol solution by direct irradiation via liquid-phase plasma. The catalyst absorbed visible-light over 610 nm. The measured bandgap of the bismuth ferrite was approximately 2.0 eV. The liquid-phase plasma emitted UV and visible-light simultaneously according to optical emission spectrometry. Bismuth ferrite induced a higher H2 production rate than the TiO2 photocatalyst because it responds to both UV and visible light generated from the liquid-phase plasma.

714 Effects of direct irradiation on cardiac implantable electronic devices

Aims Cardiac implantable electronic devices (CIEDs) may sustain damages during a course of radiation therapy, especially when the beam is directed onto the pulse generator, with device electrical reset and/or sudden battery drain. 2010 HRS/ASA expert consensus, and all CIEDs manufacturers, recommend to avoid devices direct irradiation with an accumulated dose that exceed five grays (Gy). In our prospective study, we tested the effects of direct irradiation on CIEDs with different radiation doses, also higher than 5 Gy. Methods and results Thirty-seven CIEDs of Medtronic, Abbott, Biotronik, and Boston Scientific were collected during system upgrading or lead extraction procedures. All devices were considered if they had at least 80% of residual battery capacity. All CIEDs were programmed with same default electrical parameters. Depending by CIED type, pacing mode was configured in VVI, VVIR, VDDR, or DDDR, and biventricular stimulation was activated, if present. ICDs electrical therapies were set-up with a pre-determined configuration. All devices were singularly placed in a 30 cm × 30 cm plastic bowl containing 2 l of deionized water that was placed over 5 cm Rockwool to simulate the backscatter and irradiated by a linear accelerator (Elekta Synergy®). CIEDs were divided into two groups depending on irradiation dose delivered: 5 Gy and 10 Gy. No significant differences in battery drainage were observed after irradiation respect to baseline in 5 Gy as well 10 Gy group [7.9 ± 3.1 vs. 7.5 ± 2.1 (years) battery longevity, P = 0.693; 7.7 ± 3.1 vs. 7.4 ± 2.1 (years) battery longevity, P = 0.677, respectively) (Figure). Moreover, all CIEDS saved the baseline program setting, without device reset events (Table). Conclusions Our data confirm that CIEDs direct irradiation of 5 Gy is safe, of note, direct irradiation up to 10 Gy seems to be similarly safe concerning the risk of CIEDs electrical reset and/or unexpected battery drain.

Bringing Light into Darkness—Comparison of Different Personal Dosimeters for Assessment of Solar Ultraviolet Exposure

(1) Measuring personal exposure to solar ultraviolet radiation (UVR) poses a major challenges for researchers. Often, the study design determines the measuring devices that can be used, be it the duration of measurements or size restrictions on different body parts. It is therefore of great importance that measuring devices produce comparable results despite technical differences and modes of operation. Particularly when measurement results from different studies dealing with personal UV exposure are to be compared with each other, the need for intercomparability and intercalibration factors between different measurement systems becomes significant. (2) Three commonly used dosimeter types—(polysulphone film (PSF), biological, and electronic dosimeters)—were selected to perform intercalibration measurements. They differ in measurement principle and sensitivity, measurement accuracy, and susceptibility to inaccuracies. The aim was to derive intercalibration factors for these dosimeter types. (3) While a calibration factor between PSF and electronic dosimeters of about 1.3 could be derived for direct irradiation of the dosimeters, this was not the case for larger angles of incidence of solar radiation with increasing fractions of diffuse irradiation. Electronic dosimeters show small standard deviation across all measurements. For biological dosimeters, no intercalibration factor could be found with respect to PSF and electronic dosimeters. In a use case, the relation between steady-state measurements and personal measurements was studied. On average, persons acquired only a small fraction of the ambient radiation.

Graphene under extreme electromagnetic field: energetic ion acceleration by direct irradiation of ultra intense laser on few layer suspended graphene

Atomically thin graphene is a transparent, highly electrically and thermally conductive, light-weight, and the strongest material. To date, graphene has found applications in many aspects including transport, medicine, electronics, energy, defense, and desalination. We demonstrate another disruptive application of graphene in the field of laser-ion acceleration, in which the unique features of graphene play indispensable role. Laser driven ion sources have been widely investigated for pure science, plasma diagnostics, medical and engineering applications. Recent developments of laser technologies allow us to access radiation regime of laser ion acceleration with relatively thin targets. However, the thinner target is the less durable and can be easily broken by the pedestal or prepulse through impact and heating prior to the main laser arrival. One of the solutions to avoid this is plasma mirror, which is a surface plasma created by the foot of the laser pulse on an optically transparent material working as an effective mirror only for the main laser peak. So far diamond like carbon (DLC) is used to explore the ion acceleration in extremely thin target regime (< 10 nm) with plasma mirrors, and it is necessary to use plasma mirrors even in moderately thin target regime (10-100 nm) to realize energetic ion generation. However, firstly DLC is not 2D material, and therefore, it is very expensive to make it thin and flat. Moreover, graphene is stronger than diamond at extremely thin regime, and much more reasonable for mass-production. Furthermore, installing and operating plasma mirrors at high repetition rate is also costly. Here we show another direct solution using graphene as the thinnest and strongest target ever made. We develop a facile transfer method to fabricate large-area suspended graphene (LSG) as target for laser ion acceleration with precision down to a single atomic layer. Direct irradiation of the LSG targets with an ultra intense laser generates energetic carbons and protons evidently showing the durability of graphene without plasma mirror. This extends the new frontier of science on graphene under extreme electromagnetic field, such as energy frontier and nuclear fusion.

Molecular Response of Skin to Micromachining by Femtosecond Laser

Pulsed lasers at the near infrared (NIR) range have been widely used in dermatology. Ultrashort pulsed picosecond lasers are found with the specific ability of very effective activation of skin repair and remodeling along with significant photodamage. Femtosecond lasers, with a shorter pulse width, may be a promising alternative to current NIR lasers in clinic. In this study, we performed optical micromachining by a femtosecond laser at 1,030 nm to skin of live mice in two modes of scanning of focused laser and direct irradiation by unfocused laser. The acute and one-day delayed immune molecular responses of the skin to the micromachining are studied by immunofluorescence microscopy of the skin sections. Our data shows the focused laser can activate remodeling of skin without any significant immune responses. In contrast, the direct irradiation by the unfocused laser activate significant immune responses in the deep dermis with high regulation of interleukin. Those results suggest focused femtosecond laser is of good promising potential in activation of skin remodeling and repairing with little immune or physical damage.

New fluorescent imaging technics in gastrology

Introduction. There is a need to develop a new imaging technique in medicine. Gastroenterology is the branch of medicine focused on the digestive system and its disorders therefore for this branch is needed to detect all problems affecting the gastrointestinal tract. Aim. The aim of this article is to complete discuss the possibility of the new fluorescent imaging technics in gastrology to use innovative screening to identify individuals at an early stage. Material and methods. We discuss here imaging techniques such as include x-rays, computed tomography, scans, and magnetic resonance imaging in gastrology. Spectroscopy is the study of the formation and interpretation of spectra resulting from the interaction of all types of radiation on matter understood as a community of atoms and molecules. Various spectroscopic techniques are obtained by combining different types of radiation with different ways of its interaction with the test sample. They provide the opportunity to obtain detailed information about the tested substance – from its atomic composition, through its chemical structure, to its surface structure. Analysis of the literatue. The tissue fluorescence spectrum can be obtained by: (1) autofluorescence, or natural or primary fluorescence, i.e. by direct irradiation of the tissue with laser radiation (laser-induced fluorescence – LIF) and (2) photodynamic diagnosis (PDD), where spectrum analysis is preceded by systemic or local administration of the photosensitizer. Conclusion. The use of fluorescence imaging in colon cancer patient has potential to improve quality of treatment and diagnosis.

Optical and Electrical Properties of Gold-Silver Nanoalloys Synthesized through Photochemical Reduction using Femtosecond Laser

In this work we investigated the optical and electrical properties of Au-Ag nanoalloys in various volume ratios. The nanoparticles have been prepared from gold and silver ions reduced by direct irradiation femtosecond laser. The samples were added into a quartz cuvette and irradiated for 10 minutes. Each sample was observed the optical property where surface plasmon resonance (SPR) peak was existed. In addition, electrical conductivity of the colloids was derived from the measurement of the correspond zeta potential by dynamic light scattering (DLS) method. The results showed that the SPR peak of Au-Ag nanoalloy were shifted almost linearly in between 409 nm for Ag and 530 nm for Au depending on their volume fraction. The conductivity measurement showed that Au0Ag100 (pure Ag) nanoparticles has the highest value and Au100Ag0 (pure Au) nanoparticles has the lowest value, and interestingly, Au-Ag nanoalloys have the values between Au0Ag100 and Au100Ag0. Briefly, this work revealed that both optical and electrical properties of Au-Ag nanoalloys can be easily tuned by regulating the volume fraction between the two elements.