Development of a Novel Passive Monitoring Technique to Showcase the 3D Distribution of Tritiated Water (HTO) Vapor in Indoor Air of a Nuclear Facility.

Tritiated water (HTO), a ubiquitous byproduct of the nuclear industry, is a radioactive contaminant of major concern for environmental authorities. Although understanding spatiotemporal heterogeneity of airborne HTO vapor holds great importance for radiological safety as well as diagnosing a reactor's status, comprehensive HTO distribution dynamics inside nuclear facilities has not been studied routinely yet due to a lack of appropriate monitoring techniques. For current systems, it is difficult to simultaneously achieve high representativeness, sensitivity, and spatial resolution. Here, we developed a passive monitoring scheme, including a newly designed passive sampler and a tailored analytical protocol for the first comprehensive 3D distribution characterization of HTO inside a nuclear reactor facility. The technique enables linear sampling in any environment at a one-day resolution and simultaneous preparation of hundreds of samples within 1 day. Validation experiments confirmed the method's good metrological properties and sensitivity to the HTO's spatial dynamics. The air in TU Wien's reactor hall exhibits a range of 3H concentrations from 75-946 mBq m-3 in the entire 3D matrix. The HTO release rate estimated by the mass-balance model (3199 ± 306 Bq h-1) matches the theoretical calculation (2947 ± 254 Bq h-1), suggesting evaporation as the dominant HTO source in the hall. The proposed method provides reliable and quality-controlled 3D monitoring at low cost, which can be adopted not only for HTO and may also inspire monitoring schemes of other indoor pollutants.

Interstellar

Earth is constantly bombarded with extraterrestrial dust containing invaluable information about extraterrestrial processes, such as structure formation by stellar explosions or nucleosynthesis, which could be traced back by long-lived radionuclides. Here, we report the very first detection of a recent ^{60}Fe influx onto Earth by analyzing 500 kg of snow from Antarctica by accelerator mass spectrometry. By the measurement of the cosmogenically produced radionuclide ^{53}Mn, an atomic ratio of ^{60}Fe/^{53}Mn=0.017 was found, significantly above cosmogenic production. After elimination of possible terrestrial sources, such as global fallout, the excess of ^{60}Fe could only be attributed to interstellar ^{60}Fe which might originate from the solar neighborhood.

Halogenated Alkyltetrazoles for the Rational Design of FeII Spin-Crossover Materials: Fine-Tuning of the Ligand Size.

1-(3-Halopropyl)-1H-tetrazoles and their corresponding FeII spin-crossover complexes have been investigated in a combined experimental and theoretical study. Halogen substitution was found to positively influence the spin transition, shifting the transition temperature about 70 K towards room temperature. Halogens located at the ω position were found to be too far away from the coordinating tetrazole moiety to have an electronic impact on the spin transition. The subtle variation of the steric demand of the ligand in a highly comparable series was found to have a comparatively large impact on the spin-transition behavior, which highlights the sensitivity of the effect to subtle structural changes.

Picomolar Traces of Americium(III) Introduce Drastic Changes in the Structural Chemistry of Terbium(III): A Break in the "Gadolinium Break".

The crystallization of terbium 5,5'-azobis[1H-tetrazol-1-ide] (ZT) in the presence of trace amounts (ca. 50 Bq, ca. 1.6 pmol) of americium results in 1) the accumulation of the americium tracer in the crystalline solid and 2) a material that adopts a different crystal structure to that formed in the absence of americium. Americium-doped [Tb(Am)(H2 O)7 ZT]2 ZT⋅10 H2 O is isostructural to light lanthanide (Ce-Gd) 5,5'-azobis[1H-tetrazol-1-ide] compounds, rather than to the heavy lanthanide (Tb-Lu) 5,5'-azobis[1H-tetrazol-1-ide] (e.g., [Tb(H2 O)8 ]2 ZT3 ⋅6 H2 O) derivatives. Traces of Am seem to force the Tb compound into a structure normally preferred by the lighter lanthanides, despite a 108 -fold Tb excess. The americium-doped material was studied by single-crystal X-ray diffraction, vibrational spectroscopy, radiochemical neutron activation analysis, and scanning electron microcopy. In addition, the inclusion properties of terbium 5,5'-azobis[1H-tetrazol-1-ide] towards americium were quantified, and a model for the crystallization process is proposed.

Growth and characterization of thorium-doped calcium fluoride single crystals.

We have grown [Formula: see text]Th:CaF[Formula: see text] and [Formula: see text]Th:CaF[Formula: see text] single crystals for investigations on the VUV laser-accessible first nuclear excited state of [Formula: see text]Th, with the aim of building a solid-state nuclear clock. To reach high doping concentrations despite the extreme scarcity (and radioactivity) of [Formula: see text]Th, we have scaled down the crystal volume by a factor 100 compared to established commercial or scientific growth processes. We use the vertical gradient freeze method on 3.2 mm diameter seed single crystals with a 2 mm drilled pocket, filled with a co-precipitated CaF[Formula: see text]:ThF[Formula: see text]:PbF[Formula: see text] powder in order to grow single crystals. Concentrations of [Formula: see text] cm[Formula: see text] have been realized with [Formula: see text]Th with good (> 10%) VUV transmission. However, the intrinsic radioactivity of [Formula: see text]Th drives radio-induced dissociation during growth and radiation damage after solidification. Both lead to a degradation of VUV transmission, currently limiting the [Formula: see text]Th concentration to [Formula: see text] cm[Formula: see text].

Reactivity of a hypervalent iodine trifluoromethylating reagent toward THF: ring opening and formation of trifluoromethyl ethers.

1-Trifluoromethyl-1,2-benziodoxol-3-(1H)-one (1) is able to transfer the electrophilic CF(3) group to the oxygen atom of THF in the presence of a Lewis or Bronsted acid. This results in a new ring-opening reaction of THF yielding trifluoromethyl ethers. Details of this reaction and the insight gained into the mechanism of action of reagent 1 are reported.

Bifunctional Fe(II) spin crossover-complexes based on ω-(1H-tetrazol-1-yl) carboxylic acids.

To increase the supramolecular cooperativity in Fe(ii) spin crossover materials based on N1-substituted tetrazoles, a series of ω-(1H-tetrazol-1-yl) carboxylic acids with chain-lengths of C2-C4 were synthesized. Structural characterization confirmed the formation of a strong hydrogen-bond network, responsible for enhanced cooperativity in the materials and thus largely complete spin-state transitions for the ligands with chain lenghts of C2 and C4. To complement the structural and magnetic investigation, electronic spectroscopy was used to investigate the spin-state transition. An initial attempt to utilize the bifunctional coordination ability of the ω-(1H-tetrazol-1-yl) carboxylic acids for preparation of mixed-metallic 3d-4f coordination polymers resulted in a novel one-dimensional gadolinium-oxo chain system with the ω-(1H-tetrazol-1-yl) carboxylic acid acting as µ2-η2:η1 chelating-bridging ligand.

CuSO4/[Cu(NH3)4]SO4-Composite Thermochemical Energy Storage Materials.

The thermochemical energy-storage material couple CuSO4/[Cu(NH3)4]SO4 combines full reversibility, application in a medium temperature interval (<350 °C), and fast liberation of stored heat. During reaction with ammonia, a large change in the sulfate solid-state structure occurs, resulting in a 2.6-fold expansion of the bulk material due to NH3 uptake. In order to limit this volume work, as well as enhance the thermal conductivity of the solid material, several composites of anhydrous CuSO4 with inorganic inert support materials were prepared and characterized with regard to their energy storage density, reversibility of the storage reaction, thermal conductivity, and particle morphology. The best thermochemical energy storage properties were obtained for a 10:1 CuSO4-sepiolite composite, combining an attractive energy storage density with slightly improved thermal conductivity and decreased bulk volume work compared to the pure salt.

Does [I3]+ act as an "[I]+" donor to CH3CN and N2O? Structure of [H3CCN-I-NCCH3]+ [AsF6]-.

The solid state structure of the [(CH(3)CN)(2)I](+) cation in [(CH(3)CN)(2)I][AsF(6)] was determined using single crystal X-ray diffraction. The highly reactive cation was prepared by reaction of [I(3)][AsF(6)] with CH(3)CN in liquid SO(2). In the solid state, the CNI backbone consisting of seven atoms is linear and shows a dicoordinate iodine center. The ability of [I(3)][AsF(6)] to act as a source of "[I](+)" to CH(3)CN and N(2)O is compared, and the computed structures of the [CH(3)CNI](+), [(CH(3)CN)(2)I](+), [IN(2)O](+) and [ION(2)](+) cations are discussed.

Why are UK junior doctors taking time out of training and what are their experiences? A qualitative study.

OBJECTIVES: The number of doctors directly entering UK specialty training after their foundation year 2 (F2) has steadily declined from 83% in 2010 to 42.6% in 2017. The year following F2, outside the UK training pathway, is informally termed an 'F3' year. There is a paucity of qualitative research exploring why increasingly doctors are taking F3s. The aim of this study is to explore the reasons why F2 doctors are choosing to take a year out of training and the impact upon future career choices. DESIGN: This is an exploratory qualitative study, using in-depth interviews and content analysis. SETTING: UK. PARTICIPANTS: Fourteen participants were interviewed from one foundation school. Participants included five doctors who commenced their F3 in 2015, five who started in 2016 and finally four recently starting this in 2017. MAIN OUTCOME MEASURES: Content analysis was conducted to distill the themes which exemplified the totality of the experience of the three groups. RESULTS: There were four predominant themes arising within the data set which can be framed as 'unmet needs' arising within foundation years, sought to be fulfilled by the F3 year. First, doctors describe exhaustion and stress resulting in a need for a 'break'. Second, doctors required more time to make decisions surrounding specialty applications and prepare competitive portfolios. Third, participants felt a loss of control which was (partially) regained during their F3s. The final theme was the impact of taking time out upon return to training (for those participants who had completed their F3 year). When doctors returned to NHS posts they brought valuable experience. CONCLUSIONS: This study provides evidence to support the important ongoing initiatives from Health Education England and other postgraduate bodies, exploring approaches to further engage, retain and support the junior doctor workforce.

Simple, nitrogen-rich, energetic salts of 5-nitrotetrazole.

A new family (ammonium, 1, hydrazinium, 2, guanidinium, 3, aminoguanidinium, 4, diamino-guanidinium, 5, and triaminoguanidinium, 6) of simple, nitrogen-rich energetic salts based on 5-nitro-2 H-tetrazole (HNT) were synthesized. In addition, the hemihydrate of 1 (1a) and the hydrate of 6 (6a) were also isolated. In all cases, stable salts were obtained and fully characterized by vibrational (IR, Raman) spectroscopy, multinuclear ((1)H, (13)C and (14)N) NMR spectroscopy, mass spectrometry, elemental analysis, and X-ray structure determination. Compounds 1and 2 crystallize in the monoclinic space group P2 1/c, 1a and 3 crystallize in C/2 c, 4 in P2 1/n, 5 in P2 1, 6 in orthorhombic P2 12 12 1, and 6a in triclinic P1. Initial safety testing (impact, friction, and electrostatic sensitivity) and thermal stability measurements (DSC) were also carried out. The NT salts all exhibit good thermal stabilities (decomposition above 150 degrees C). The constant volume energies of combustion (Delta c U(exp)) of 1-6 were experimentally determined by oxygen bomb calorimetry to be -1860(30) cal/g ( 1), -1770(30) cal/g ( 1a), -2110(150) cal/g (2), -2250(40) cal/g ( 3), -2470(30) cal/g (4), -2630(40) cal/g (5), -2690(50) cal/g (6), and -2520(50) cal/g (6a). Because of the significant experimental uncertainties obtained in these measurements, their validity was checked by way of quantum chemical calculation (MP2) of electronic energies and an approximation of lattice enthalpy. The predicted constant volume energies of combustion (Delta c U(pred)) calculated by this method were -2095.9 cal/g (1), -1975.7 cal/g ( 1a), -2362.4 cal/g (2), -2526.6 cal/g (3), -2654.6 cal/g (4), -2778.6 cal/g ( 5), -2924.0 cal/g (6), and -2741.4 cal/g ( 6a). From the experimentally determined density, chemical composition, and energies of formation (back calculated from the heats of combustion) the detonation pressures and velocities of 1 (7950 m/s, 23.9 GPa), 1a (7740 m/s, 22.5 GPa), 2(8750 m/s, 30.1 GPa), 3 (7500 m/s, 20.1 GPa) 4(8190 m/s, 24.7 GPa), 5(8230 m/s, 24.4 GPa), 6 (8480 m/s, 26.0 GPa) and 6a (7680 m/s, 20.7 GPa) were predicted using the EXPLO5 code.

Adsorption characteristics of a clinoptilolite-rich zeolite compound for Sr and Cs.

The Sr and Cs adsorption capacities of LithoFill™, LithoGran™ and a competing clinoptilolite containing zeolite product were investigated by radioanalytical methods (85Sr and 134Cs gamma spectroscopy). The dependence of adsorption and adsorption rate on physical factors including temperature, available ions and time were assessed. In addition, the reversibility of adsorption under high ionic strength conditions was also examined. In general, cesium is more strongly adsorbed than strontium, adsorption yields are generally independent of temperature (from room temperature to 65 °C) and adsorption is relatively rapid (identical results for 2 or 5 day adsorption times). As expected, increasing the concentration of other ions in solution tends to reduce adsorption of cesium and strontium. In general, Cs adsorption ranges between 54.5 and 45.2 mg/g for LitoFill and LitoGran samples and between 36.9 and 24.4 mg/g for the competing product. For Sr adsorption, ranges are 30-21 mg/g and 7.3-6.7 mg/g respectively, leading to the conclusion that the higher content of clinoptilolite in the LitoFill/LitoGran samples results in better adsorption characteristics.

Cooperativity in spin crossover materials as ligand's responsibility - investigations of the Fe(ii) - 1,3-bis((1H-tetrazol-1-yl)methyl)bicyclo[1.1.1]pentane system.

Criteria for a technologically relevant spin crossover (SCO) material include temperature and abruptness. A series of Fe(ii) - 1,3-bis((1H-tetrazol-1-yl)methyl)bicyclo[1.1.1]pentane SCO complexes with various anions (BF4-, ClO4-, and PF6-) designed using a structure-property based concept is reported. All complexes feature abrupt SCO-behavior with T1/2 between 170 K and 187 K. These materials demonstrate that without stabilizing the effects of incorporated solvents or a hydrogen bond-network, the observed cooperativity during high-spin-low-spin transition is anion independent and originates only from the rigidity and internal strain of the propellane-moiety in the ligand. Spectroscopy and structural investigations of these materials are supported by quantum chemical calculations.

Mental and sexual health outcomes following sexual assault in adolescents: a prospective cohort study.

BACKGROUND: Young people are disproportionately affected by sexual assault, yet longitudinal data are sparse. This paper examines the characteristics of adolescents presenting to sexual assault services and mental and sexual health outcomes after an assault. METHODS: This was a prospective cohort study in adolescents aged 13-17 years attending the Sexual Assault Referral Centres serving Greater London, UK, over 2 years. Baseline interviews (T0) were done less than 6 weeks after an assault to collect data on sociodemographic and assault characteristics and psychological symptoms, with follow-up interviews (T1) at 4-5 months after the assault. Four psychological symptom questionnaires were used at T0 and T1: The Child Revised Impact of Events Scale, the Short Mood and Feelings Questionnaire, the Screen for Child Anxiety Related Disorders, and the Strengths and Difficulties Questionnaire. The primary outcome was prevalence of any psychiatric disorder at T1, assessed using the Development and Wellbeing Assessment. Secondary outcomes at T1 were pregnancy, sexually transmitted infections, and sexual health screening since the assault. FINDINGS: Between April 15, 2013, and April 20, 2015, 141 (29%) of 491 eligible young people were recruited to the study (134 females; mean age 15·6 years [SD 1·27]), and 106 (75%) of 141 participants had T1 interviews (99 female). At T0, psychological symptom scores showed that 115 (88%) of 130 females were at risk for depressive disorder, 90 (71%) of 126 were at risk for anxiety disorders, and 116 (91%) of 128 were at risk for post-traumatic stress disorder, with symptoms largely persisting at T1. 68 (80%) of 85 females who had a diagnostic assessment at T1 had a psychiatric disorder, with multiple disorders in 47 (55%) of 85. Anxiety, post-traumatic stress, and major depressive disorders were the commonest diagnoses. Presence of a psychiatric disorder was associated with baseline psychosocial vulnerability (previous social services involvement, mental health service use, self-harm, or sexual abuse), but not assault characteristics. At T1, four (4%) of 105 females had been pregnant since the assault, 14 (12%) of 119 had a sexually transmitted infection diagnosed between T0 and T1, and nine (8%) of 107 reported re-victimisation since the assault. INTERPRETATION: Vulnerable adolescents have the double disadvantage of being at risk for both sexual assault and associated psychiatric disorders, highlighting the need for comprehensive support after an assault. Feasibility and effectiveness of prevention programmes should be investigated. FUNDING: National Institute for Health Research Policy Research Programme grant (115/0001).

Cycle Stability and Hydration Behavior of Magnesium Oxide and Its Dependence on the Precursor-Related Particle Morphology.

Thermochemical energy storage is considered as an auspicious method for the recycling of medium-temperature waste heat. The reaction couple Mg(OH)2⁻MgO is intensely investigated for this purpose, suffering so far from limited cycle stability. To overcome this issue, Mg(OH)2, MgCO3, and MgC2O4·2H2O were compared as precursor materials for MgO production. Depending on the precursor, the particle morphology of the resulting MgO changes, resulting in different hydration behavior and cycle stability. Agglomeration of the material during cyclization was identified as main reason for the decreased reactivity. Immersion of the spent material in liquid H2O decomposes the agglomerates restoring the initial reactivity of the material, thus serving as a regeneration step.

Long-term environmental radioactive contamination of Europe due to the Chernobyl accident - Results of the Joint Danube Survey 2013.

In the course of the Joint Danube Survey 3 (JDS3), coordinated by the International Commission for the Protection of the Danube River (ICPDR), laboratory ships travelled 2375km down the Danube River engaging in sampling, processing and on-board analyses during the summer of 2013. The results of the radiometric analysis of 90Sr, 137Cs and natural radionuclides in recent riverbed sediment are presented. The activity concentrations of 90Sr and 137Cs in Danube sediments have been found below 100Bq/kg.

Medical care following multiple perpetrator sexual assault: a retrospective review.

This paper describes the healthcare needs of victims of multiple perpetrator sexual assault (MPSA) and single perpetrator sexual assault (SPSA) presenting to the Haven sexual assault referral centre in south-east London, and aims to identify any characteristics that might be related to attendance at follow-up appointments. We reviewed standardised casenotes of 136 MPSA victims and 139 SPSA victims attending for forensic medical examination (FME) between 1 July 2005 and 31 July 2009. MPSA victims reported a higher rate of stranger assaults, higher rates of vaginal, anal and oral rapes, more rapes at multiple anatomical sites or multiple rapes and were more likely to sustain injuries, all of which put MPSA victims at higher risk of subsequent health problems. Rates of attendance at follow-up appointments were low for all (53.5%) as were rates of completion of post-exposure prophylaxis (PEP) for HIV (33.3%). Attendance at follow-up was associated with presence of anogenital injury at the time of FME. Those over the age of 30 years were less likely to attend.

Encouraging formative assessments of leadership for foundation doctors.

BACKGROUND: Clinical leadership is considered essential for maintaining and improving patient care and safety in the UK, and is incorporated in the curriculum for all trainee doctors. CONTEXT: Despite the growing focus on the importance of leadership, and the introduction of the Medical Leadership Competency Framework (MLCF) in the UK, leadership education for doctors in training is still in its infancy. Assessment is focused on clinical skills, and trainee doctors receive very little formal feedback on their leadership competencies. INNOVATION: In this article we describe the approach taken by Health Education Kent, Sussex and Surrey (HEKSS) to raise the profile of leadership amongst doctors in training in the South Thames Foundation School (STFS). An annual structured formative assessment in leadership for each trainee has been introduced, supported by leadership education for both trainees and their supervisors in HEKSS trusts. We analysed over 500 of these assessments from the academic year 2012/13 for foundation doctors in HEKSS trusts, in order to assess the quality of the feedback. From the analysis, potential indicators of more effective formative assessments were identified. These may be helpful in improving the leadership education programme for future years. IMPLICATIONS: There is a wealth of evidence to highlight the importance and value of formative assessments; however, particularly for foundation doctors, these have typically been focused on assessing clinical capabilities. This HEKSS initiative encourages doctors to recognise leadership opportunities at the beginning of their careers, seeks to help them understand the importance of acquiring leadership skills and provides structured feedback to help them improve. Leadership education for doctors in training is still in its infancy.

Drug resistance is uncommon in pregnant women with low viral loads taking zidovudine monotherapy to prevent perinatal HIV transmission.

Zidovudine monotherapy is used to reduce perinatal HIV transmission in women with low viral loads. There are few data on the risk of drug resistance in this select cohort of women. We determined the prevalence of newly acquired mutations conferring reduced sensitivity to zidovudine after exposure during pregnancy, and found that the development of mutations was uncommon and was restricted to women treated before 1998 who had higher baseline viral loads than those currently recommended monotherapy.