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Background and purpose: Oxygen dynamics may be important for the tissue-sparing effect observed at ultra-high dose rates (FLASH sparing effect). This study investigated the correlation between local instantaneous dose rate and radiation-induced oxygen pressure reduction during proton pencil beam scanning (PBS) irradiations of a sample and quantified the oxygen consumption g-value. Materials and methods: A 0.2 ml phosphorescent sample (1 µM PtG4 Oxyphor probe in saline) was irradiated with a 244 MeV proton PBS beam. Four irradiations were performed with variations of a PBS spot pattern with 5 × 7 spots. During irradiation, the partial oxygen pressure (pO2) was measured with 4.5 Hz temporal resolution with a phosphorometer (Oxyled) that optically excited the probe and recorded the subsequently emitted light. A calibration was performed to calculate the pO2 level from the measured phosphorescence lifetime. A fiber-coupled scintillator simultaneously measured the instantaneous dose rate in the sample with 50 kHz sampling rate. The oxygen consumption g-value was determined on a spot-by-spot level and using the total pO2 change for full spot pattern irradiation. Results: A high correlation was found between the local instantaneous dose rate and pO2 reduction rate, with a correlation coefficient of 0.96-0.99. The g-vales were 0.18 ± 0.01 mmHg/Gy on a spot-by-spot level and 0.17 ± 0.01 mmHg/Gy for full spot pattern irradiation. Conclusions: The pO2 reduction rate was directly related to the local instantaneous dose rate per delivered spot in PBS deliveries. The methodology presented here can be applied to irradiation at ultra-high dose rates with modifications in the experimental setup.

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This study aimed to confirm the presence of gingival inflammation through image analysis of the papillary gingiva using intra-oral photographs (IOPs) before and after orthodontic treatment and to confirm the possibility of using gingival image analysis for gingivitis screening. Five hundred and eighty-eight (n = 588) gingival sites from the IOPs of 98 patients were included. Twenty-five participants who had completed their orthodontic treatments and were aged between 20 and 37 were included. Six points on the papillary gingiva were selected in the maxillary and mandibular anterior incisors. The red/green (R/G) ratio values were obtained for the selected gingival images and the modified gingival index (GI) was compared. The change in the R/G values during the orthodontic treatment period appeared in the order of before orthodontic treatment (BO), mid-point of orthodontic treatment (MO), three-quarters of the way through orthodontic treatment (TO), and immediately after debonding (IDO), confirming that it was similar to the change in the GI. The R/G value of the gingiva in the image correlated with the GI. Therefore, it could be used as a major index for gingivitis diagnosis using images.

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In hydrated electron (e-aq) dosimetry, absorbed radiation dose to water is measured by monitoring the concentration of radiation-induced e-aq. However, to obtain accurate dose, the radiation chemical yield of e-aq, G(e-aq), is needed for the radiation quality/setup under investigation. The aim of this study was to investigate the time-evolution of the G-values for the main generated reactive species during water radiolysis using GEANT4-DNA. The effects of cluster size and linear energy transfer (LET) on G(e-aq) were examined. Validity of GEANT4-DNA for calculation of G(e-aq) for clinically relevant energies was studied. Three scenarios were investigated with different phantom sizes and incoming electron energies (1 keV to 1 MeV). The time evolution of G(e-aq) was in good agreement with published data and did not change with decreasing phantom size. The time-evolution of the G-values increases with increasing LET for all radiolytic species. The particle tracks formed with high-energy electrons are separated and the resulting reactive species develop independently in time. With decreasing energy, the mean separation distance between reactive species decreases. The particle tracks might not initially overlap but will overlap shortly thereafter due to diffusion of reactive species, increasing the probability of e-aq recombination with other species. This also explains the decrease of G(e-aq) with cluster size and LET. Finally, if all factors are kept constant, as the incoming electron energy increases to clinically relevant energies, G(e-aq) remains similar to its value at 1 MeV, hence GEANT4-DNA can be used for clinically relevant energies.

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To attain a comfortable building interior, building windows play a crucial role. Because of the transparent nature of the window, it allows heat loss and gain and daylight. Thus, they are one of the most crucial parts of the building envelope that have a significant contribution to the overall building energy consumption. The presence of dust particles on a window can change the entering light spectrum and creates viewing issues. Thus, self-cleaning glazing is now one of the most interesting research topics. However, aside from the self-cleaning properties, there are other properties that are nominated as glazing factors and are imperative for considering self-cleaning glazing materials. In this work, for the first time, Hf-doped ZnO was investigated as self-cleaning glazing and its glazing factors were evaluated. These outcomes show that the various percentages of ZnO doping with Hf improved the glazing factors, making it a suitable glazing candidate for the cold-dominated climate.

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B12 coenzymes are vital to healthy biological function across nature. They undergo radical chemistry in a variety of contexts, where spin-correlated radical pairs can be generated both thermally and photochemically. Owing to the unusual magnetic properties of B12 radical pairs, however, most of the reaction and spin dynamics occur on a timescale (picoseconds-nanoseconds) that cannot be resolved by most measurement techniques. Here, we describe a method that combines femtosecond transient absorption spectroscopy with magnetic field exposure, which enables the direct scrutiny of such rapid processes. This approach should provide a means by which to investigate the apparently profound effect protein environments have on the generation and reactivity of B12 radical pairs.

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Modified structure along latent tracks and track formation process have been investigated in poly (allyl diglycol carbonate), PADC, which is well recognized as a sensitive etched track detector. This knowledge is essential to develop novel detectors with improved track registration property. The track structures of protons and heavy ions (He, C, Ne, Ar, Fe, Kr and Xe) have been examined by means of FT-IR spectrometry, covering the stopping power region between 1.2 to 12,000 eV/nm. Through a set of experiments on low-LET radiations-such as gamma ray-, multi-step damage process by electron hits was confirmed in the radiation-sensitive parts of the PADC repeat-unit. From this result, we unveiled for the first-time the layered structure in tracks, in relation with the number of secondary electrons. We also proved that the etch pit was formed when at least two repeat-units were destroyed along the track radial direction. To evaluate the number of secondary electrons around the tracks, a series of numerical simulations were performed with Geant4-DNA. Therefore, we are proposing new physical criterions to describe the detection thresholds. Furthermore, we propose a present issue of the definition of detection threshold for semi-relativistic C ions. Additionally, as a possible chemical criterion, formation density of hydroxyl group is suggested to express the response of PADC.

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Spin Hamiltonian parameters of a pentanuclear Os 2 III Ni 3 II cyanometallate complex are derived from ab initio wave function based calculations, namely valence-type configuration interaction calculations with a complete active space including spin-orbit interaction (CASOCI) in a single-step procedure. While fits of experimental data performed so far could reproduce the data but the resulting parameters were not satisfactory, the parameters derived in the present work reproduce experimental data and at the same time have a reasonable size. The one-centre parameters (local g matrices and single-ion zero field splitting tensors) are within an expected range, the anisotropic exchange parameters obtained in this work for an Os-Ni pair are not exceedingly large but determine the low-T part of the experimental χT curve. Exchange interactions (both isotropic and anisotropic) obtained from CASOCI have to be scaled by a factor of 2.5 to obtain agreement with experiment, a known deficiency of such types of calculation. After scaling the parameters, the isotropic Os-Ni exchange coupling constant is J = - 4 . 2  cm-1 and the D parameter of the (nearly axial) anisotropic Os-Ni exchange is D = J ∥ - J ⊥ = 18 . 8 c m -1 , so anisotropic exchange is larger in absolute size than isotropic exchange. The negative value of the isotropic J (indicating antiferromagnetic coupling) seemingly contradicts the large-temperature behaviour of the temperature dependent susceptibility curve, but this is caused by the negative g value of the Os centres. This negative g value is a universal feature of a pseudo-octahedral coordination with t 2 g 5 configuration and strong spin-orbit interaction. Knowing the size of these exchange interactions is important because Os(CN) 6 3 - is a versatile building block for the synthesis of 5 d / 3 d magnetic materials.

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A review of the applicability of electron beam water radiolysis for sewage sludge treatment is presented. Electron beam treatment has been proven to be a successful approach to the disinfection of both wastewater and sewage sludge. Nevertheless, before 2000, there were concerns about the perceived high capital costs of the accelerator and with public acceptance of the usage of radiation for water treatment purposes. Nowadays, with increased knowledge and technological development, it may be not only possible but also desirable to use electron beam technology for risk-free sewage sludge treatment, disposal and bio-friendly fertiliser production. Despite the developing interest in this method, there has been no attempt to perform a review of the pertinent literature relating to this technology. It appears that understanding of the mechanism and primary parameters of disinfection is key to optimising the process. This paper aims to reliably characterise the sewage sludge electron beam treatment process to elucidate its major issues and make recommendations for further development and research. Graphical abstract.

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BACKGROUND: The apparent disconnection between biological complexity and both genome size (C-value) and gene number (G-value) is one of the long-standing biological puzzles. Gene-dense genomic sequences in prokaryotes or simple eukaryotes are highly constrained during selection, whereas gene-sparse genomic sequences in higher eukaryotes have low selection constraints. This review discusses the correlations of the C-value and G-value with genome architecture, polyploidy, repeatomes, introns, cell economy and phenomes. DISCUSSION: Eukaryotic chromosomes carry an assortment of various repeated DNA sequences (repeatomes). Expansion of copies of repeatomes together with polyploidization or whole-genome duplication (WGD) are major players in genome size (C-value) bloating, but genomes are equipped with counterbalancing systems such as diploidization, illegitimate recombination, and nonhomologous end joining (NHEJ) after double-strand breaks (DSBs). The lack of these efficient purging systems allowed the accumulation of repeat DNA, which resulted in extremely large genomes in several species. However, the correlation between chromosome number and genome size is not clear due to inconsistent results with different sets of species. Positive correlations between genome size and intron size and density were reported in early studies, but these proposals were refuted by the results with increased numbers of species, in which genome-wide features of introns (size, density, gene contents, repeats) were weakly associated with genome size. The assumption of the correlations between C-value and gene number (G-value) and organismal complexity is acceptable in general, but this assumption is often violated in specific lineages or species, suggesting C- and G-value paradoxes. The C-value paradox is partly explained by noncoding repeatomes. The G-value paradox can also be explained by several genomic features: (1) one gene can produce many mature mRNAs by alternative splicing, and eukaryotic gene expression is highly regulated at both the transcriptional and translational levels; (2) many proteins exert multiple functions during development; (3) gene expansion/contraction are frequent events in the gene family among evolutionarily close species; and (4) sets of homeotic genes regulate development such that organismal complexity is sometimes not clear among organisms. A large genome must be burdensome in terms of cell economy, such that a large genome constraint results in the distribution of genome sizes skewed to small genomes. Moreover, the C-value can affect the phenome. A strong positive correlation has been recognized between genome size and cell size, but the relationship is weak or null with higher-level traits. Additional analyses of the relationship between the C-value and phenome should be carried out, because natural selection acts on the phenotype rather than the genotype. CONCLUSIONS: Dramatic advancement in genomics has given some answers to the C-value and G-value paradoxes. We know the mechanisms by which the current genomes have been constructed. However, basic questions have not yet been fully resolved. Why have some species retained small genomes yet some closely related species have large genomes? Random genetic drift and mutational pressure might have affected for genome size in the limited population size during evolution; thus, genome size may be quasiadaptable rather than the best adaptive trait.

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A flowing-water target was irradiated with a 140 MeV/u, 8 nA 40Ca20+ beam to test the feasibility of isotope harvesting at the upcoming Facility for Rare Isotope Beams. Among other radionuclides, 2.6(2)E-6 48Cr and 5.6(5)E-6 28 Mg nuclei were formed for every impingent 40Ca and were collected through ion exchange. Radiolysis-induced molecular hydrogen evolved from the target at an initial rate of 0.91(9) H2 molecules per 100 eV of beam energy deposited. No radiation-accelerated corrosion of the target material was observed.

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Environmentally persistent free radicals (EPFRs) are a new class of pollutants that are long-lived in fine particles (PM2.5), i.e., their 1/e lifetime ranges from days to months (or even infinite). They are capable of producing harmful reactive oxygen species such as hydroxyl radicals. The redox cycling of EPFRs is considered as an important pathway for PM2.5 to induce oxidative stress inside the humans, causing adverse health effects such as respiratory and cardiovascular diseases. Consequently, research regarding their toxicity, formation and environmental occurrences in PM2.5 has attracted increasing attentions globally during the past two decades. However, literature data in this field remain quite limited and discrete. Hence, an extensive review is urgently needed to summarize the current understanding of this topic. In this work, we systematically reviewed the analytical methods and environmental occurrences, e.g., types, concentrations, and decay behaviors, as well as possible sources of EPFRs in PM2.5. The types of pretreatment methods, g-values of common EPFRs and categories of decay processes were discussed in detail. Moreover, great efforts were made to revisit the original data of the published works of EPFRs in airborne particulate matter and provided additional useful information for comparison where possible, e.g., their mean and standard deviation of g-values, line widths (ΔH p-p), and concentrations. Finally, possible research opportunities were highlighted to further advance our knowledge of this emerging issue.

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Pyrolysis is a promising way to convert biomass into fuels and chemicals. This reaction is complex and inevitably involves a cascade of radical reactions that lead to char formation, in which some radicals become trapped and stabilized. Their nature is difficult to characterize, and in this respect computational chemistry can be a strong supplementary tool to electron spin resonance spectroscopy and other experimental methods. Here biomass char radicals and oxidation reactivity are studied experimentally, and density functional theory is used to predict the thermodynamic stability and g-values of carbon- and oxygen-centered radicals of polyaromatic char models including defect structures. Hydroxylated and especially certain dihydroxylated structures provide exceptional stabilization of oxygen-centered radicals. Hydrogen bonding plays a crucial role, and it is proposed that hydrogen atom transfer couples radical localizations. This is a new proposal on the structural requirements for stabilization of char radicals, which impacts our understanding of pyrolysis mechanisms and char reactivity.

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Triethanolamine, teaH3, and diethanolamine, RdeaH2, 3d-4f and 4f compounds demonstrate an enormous variety in their structure and bonding. This review examines the synthetic strategies to these molecules and their magnetic properties, whilst trying to assess these ligands' suitability towards new SMMs and magnetic refrigerants.

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The paper presents an innovative approach towards development of real time dosimetry using a chemical dosimeter for measurement of absorbed radiation dose in the range between 1 and 400 Gy. Saturated chloroform solution in water, a well known chemical dosimeter, is used to demonstrate the concept of online measurement of radiation dose. The measurement approach involves online monitoring of increase in conductivity of saturated chloroform solution due to progressive build up of traces of highly conducting HCl during exposure to gamma irradiation. A high performance pulsating sensor-based conductivity monitoring instrument has been used to monitor such real time change in conductivity of solution. A relation between conductivity shift and radiation dose has been established using radiochemical yield value (G value) of HCl. The G value of HCl in saturated chloroform dosimeter has been determined using laboratory developed pulsating sensor-based devices. In this connection dose rate of Co-60 gamma chamber was determined using Fricke dosimeter following a simple potentiometric measurement approach developed in-house besides conventional spectrophotometry. Results obtained from both measurement approaches agreed well. Complete instrumentation package has also been developed to measure real time radiation dose. The proposed real time radiation dosimeter is successfully tested in several measurement campaigns in order to assure its performance prior to its deployment in field.

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Five-monolayer (5ML) plasmid DNA films deposited on glass and tantalum substrates were exposed to Al Kα X-rays of 1.5 keV under gaseous nitrous oxide (N2O) at atmospheric pressure and temperature. Whereas the damage yields for DNA deposited on glass are due to soft X-rays, those arising from DNA on tantalum are due to both the interaction of low energy photoelectrons from the metal and X-rays. Then, the differences in the yields of damage on glass and tantalum substrates, essentially arises from interaction of essentially low-energy electrons (LEEs) with DNA molecules and the surrounding atmosphere. The G-values (i.e., the number of moles of product per Joule of energy absorbed) for DNA strand breaks induced by LEEs (GLEE) and the lower limit of G-values for soft X-ray photons (GXL) were calculated and the results compared to those from previous studies under atmospheric conditions and other ambient gases, such as N2 and O2. Under N2O, the G-values for loss of supercoiled DNA are 103±15 nmol/J for X-rays, and 737±110 nmol/J for LEEs. Compared to corresponding values in an O2 atmosphere, the effectiveness of X-rays to damage DNA in N2O is less, but the G value for LEEs in N2O is more than twice the corresponding value for an oxygenated environment. This result indicates a higher effectiveness for LEEs relative to N2 and O2 environments in causing SSB and DSB in an N2O environment. Thus, the previously observed radiosensitization of cells by N2O may not be only due to OH• radicals but also to the reaction of LEE with N2O molecules near DNA. The previous experiments with N2 and O2 and the present one demonstrate the possibility to investigate damage induced by LEEs to biomolecules under various type of surrounding atmospheres.