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Prolonged survival of SARS-CoV-2 on environmental surfaces and personal protective equipment may lead to these surfaces transmitting disease to others. This article reports the effectiveness of a pulsed xenon ultraviolet disinfection system in reducing the load of SARS-CoV-2 on hard surfaces and N95 respirators.
Chamber slides and N95 respirator material were directly inoculated with SARS-CoV-2 and exposed to different durations of pulsed xenon ultraviolet disinfection.
For hard surfaces, disinfection for 1, 2, and 5 minutes resulted in 3·53 Log10, >4·54 Log10, and >4·12 Log10 reductions in viral load, respectively. For N95 respirators, disinfection for 5 minutes resulted in >4·79 Log10 reduction in viral load. We found that pulsed xenon ultraviolet significantly reduces SARS-CoV-2 on hard surfaces and N95 respirators.
With the potential to rapidly disinfectant environmental surfaces and N95 respirators, pulsed xenon ultraviolet devices are a promising technology for the reduction of environmental and personal protective equipment bioburden and to enhance both healthcare worker and patient safety by reducing the risk of exposure to SARS-CoV-2.
Residual strain in electrodeposited Li films may affect safety and performance in Li metal battery anodes, so it is important to understand how to detect residual strain in electrodeposited Li and the conditions under which it arises. To explore this Li films, electrodeposited onto Cu metal substrates, were prepared under an applied pressure of either 10 or 1000 kPa and subsequently tested for the presence or absence of residual strain via sin2(ψ) analysis. X-ray diffraction (XRD) analysis of Li films required preparation and examination within an inert environment; hence, a Be-dome sample holder was employed during XRD characterization. Results show that the Li film grown under 1000 kPa displayed a detectable presence of in-plane compressive strain (−0.066%), whereas the Li film grown under 10 kPa displayed no detectable in-plane strain. The underlying Cu substrate revealed an in-plane residual strain near zero. Texture analysis via pole figure determination was also performed for both Li and Cu and revealed a mild fiber texture for Li metal and a strong bi-axial texture of the Cu substrate. Experimental details concerning sample preparation, alignment, and analysis of the particularly air-sensitive Li films have also been detailed. This work shows that Li metal exhibits residual strain when electrodeposited under compressive stress and that XRD can be used to quantify that strain.
The second and final year of the Erasmus Plus programme ‘Innovative Education and Training in high power laser plasmas’, otherwise known as PowerLaPs, is described. The PowerLaPs programme employs an innovative paradigm in that it is a multi-centre programme, where teaching takes place in five separate institutes with a range of different aims and styles of delivery. The ‘in-class’ time is limited to 4 weeks a year, and the programme spans 2 years. PowerLaPs aims to train students from across Europe in theoretical, applied and laboratory skills relevant to the pursuit of research in laser plasma interaction physics and inertial confinement fusion. Lectures are intermingled with laboratory sessions and continuous assessment activities. The programme, which is led by workers from the Hellenic Mediterranean University and supported by co-workers from the Queen’s University Belfast, the University of Bordeaux, the Czech Technical University in Prague, Ecole Polytechnique, the University of Ioannina, the University of Salamanca and the University of York, has just finished its second and final year. Six Learning Teaching Training activities have been held at the Queen’s University Belfast, the University of Bordeaux, the Czech Technical University, the University of Salamanca and the Institute of Plasma Physics and Lasers of the Hellenic Mediterranean University. The last of these institutes hosted two 2-week-long Intensive Programmes, while the activities at the other four universities were each 5 days in length. In addition, a ‘Multiplier Event’ was held at the University of Ioannina, which will be briefly described. In this second year, the work has concentrated on training in both experimental diagnostics and simulation techniques appropriate to the study of plasma physics, high power laser matter interactions and high energy density physics. The nature of the programme will be described in detail, and some metrics relating to the activities carried out will be presented. In particular, this paper will focus on the overall assessment of the programme.
Audits play a critical role in maintaining the integrity of observational cohort data. While previous work has validated the audit process, sending trained auditors to sites (“travel-audits”) can be costly. We investigate the efficacy of training sites to conduct “self-audits.”
In 2017, eight research groups in the Caribbean, Central, and South America network for HIV Epidemiology each audited a subset of their patient records randomly selected by the data coordinating center at Vanderbilt. Designated investigators at each site compared abstracted research data to the original clinical source documents and captured audit findings electronically. Additionally, two Vanderbilt investigators performed on-site travel-audits at three randomly selected sites (one adult and two pediatric) in late summer 2017.
Self- and travel-auditors, respectively, reported that 93% and 92% of 8919 data entries, captured across 28 unique clinical variables on 65 patients, were entered correctly. Across all entries, 8409 (94%) received the same assessment from self- and travel-auditors (7988 correct and 421 incorrect). Of 421 entries mutually assessed as “incorrect,” 304 (82%) were corrected by both self- and travel-auditors and 250 of these (72%) received the same corrections. Reason for changing antiretroviral therapy (ART) regimen, ART end date, viral load value, CD4%, and HIV diagnosis date had the most mismatched corrections.
With similar overall error rates, findings suggest that data audits conducted by trained local investigators could provide an alternative to on-site audits by external auditors to ensure continued data quality. However, discrepancies observed between corrections illustrate challenges in determining correct values even with audits.
The aim of this study was the construction and validation of a novel research instrument to quantify the degree of post-hurricane trauma and distress in an affected population. The Post-Hurricane Distress Scale (PHDS) has quantitative measures of both acute and prolonged distress, attributable to meteorological and hydrological disasters.
A careful evaluation of existing questionnaires, as well as extensive canvasing of the post-Maria population of Puerto Rico, availed the construction of the PHDS. The PHDS consists of 20 items, organized into 4 subscales. The PHDS was pre-validated (n=79), revised, and then distributed to a broad sampling of the post-Hurricane Maria Puerto Rican population (n=597). Validation, including factor analysis, analyses of concurrent validity, discriminant validity, and internal reliability, was performed.
After comparing various scales, factor loading profiles, concurrent validities, and models of fit, we show that the PHDS is best scored as a single 0–6 distress scale. When compared with the Traumatic Exposure Severity Scale, the PHDS shows superior concurrent validity, more accurately predicting scores for the Peritraumatic Distress Inventory, Impact of Event Scale – Revised, and Generalized Anxiety Disorder 7 Scale. The PHDS shows good internal reliability and discriminant validity.
The PHDS represents a novel, useful instrument for disaster first-responders and researchers. The prompt identification of high-risk populations is possible using this instrument. (Disaster Med Public Health Preparedness. 2019;13:82-89)
Williams syndrome (WS) is a neurodevelopmental disorder that results from a heterozygous microdeletion on chromosome 7q11.23. Most of the time, the affected region contains ~1.5 Mb of sequence encoding approximately 24 genes. Some 5–8% of patients with WS have a deletion exceeding 1.8 Mb, thereby affecting two additional genes, including GTF2IRD2. Currently, there is no consensus regarding the implications of GTF2IRD2 loss for the neuropsychological phenotype of WS patients. Objectives: The present study aimed to identify the role of GTF2IRD2 in the cognitive, behavioral, and adaptive profile of WS patients. Methods: Twelve patients diagnosed with WS participated, four with GTF2IRD2 deletion (atypical WS group), and eight without this deletion (typical WS group). The age range of both groups was 7–18 years old. Each patient’s 7q11.23 deletion scope was determined by chromosomal microarray analysis. Cognitive, behavioral, and adaptive abilities were assessed with a battery of neuropsychological tests. Results: Compared with the typical WS group, the atypical WS patients with GTF2IRD2 deletion had more impaired visuospatial abilities and more significant behavioral problems, mainly related to the construct of social cognition. Conclusions: These findings provide new evidence regarding the influence of the GTF2IRD2 gene on the severity of behavioral symptoms of WS related to social cognition and certain visuospatial abilities. (JINS, 2018, 24, 896–904)
The Florida Department of Health in Miami-Dade County (DOH-Miami-Dade) investigated 106 reported carbon monoxide (CO) exposures over a 9-day timeframe after Hurricane Irma. This report evaluates risk factors for CO poisoning and the importance of heightened surveillance following natural disasters.
Data on CO poisoning cases from September 9 to 18, 2017 were extracted from Merlin, the Florida Department of Health Surveillance System. Medical records were obtained and follow-up interviews were conducted to collect data on the confirmed CO poisoning cases. Data were analyzed using SAS v9.4.
Ninety-one of the 106 people exposed to CO met the case definition for CO poisoning: 64 confirmed, 7 probable, and 20 suspect cases. Eighty-eight percent of the affected individuals were evaluated in emergency departments and 11.7% received hyperbaric oxygen treatment. The most frequently reported symptoms included headache (53.3%), dizziness (50.7%), and nausea (46.7%). Three patients expired due to their exposure to CO.
Post Hurricane Irma, the DOH-Miami-Dade investigated numerous cases for CO exposure. By understanding who is most likely to be impacted by CO and the impact of generators’ location on people’s health, education efforts can be tailored to the population most at risk and further CO exposures and related mortalities following natural disasters can be reduced. (Disaster Med Public Health Preparedness. 2019;13:94–96)
The powder-bed laser additive manufacturing (AM) process is widely used in the fabrication of three-dimensional metallic parts with intricate structures, where kinetically controlled diffusion and microstructure ripening can be hindered by fast melting and rapid solidification. Therefore, the microstructure and physical properties of parts made by this process will be significantly different from their counterparts produced by conventional methods. This work investigates the microstructure evolution for an AM fabricated AlSi10Mg part from its nonequilibrium state toward equilibrium state. Special attention is placed on silicon dissolution, precipitate formation, collapsing of a divorced eutectic cellular structure, and microstructure ripening in the thermal annealing process. These events alter the size, morphology, length scale, and distribution of the beta silicon phase in the primary aluminum, and changes associated with elastic properties and microhardness are reported. The relationship between residual stress and silicon dissolution due to changes in lattice spacing is also investigated and discussed.
X-ray fluorescence (XRF) has been employed as one of several orthogonal means of screening materials to prevent counterfeit and adulterated products from entering the product stream. We document the use of principal component analysis (PCA) of XRF data on compositionally similar and dissimilar stainless steels for the purpose of testing the feasibility of employing XRF spectra to parse and bin these alloys as the same or significantly different alloy materials. The results indicate that XRF spectra can separate and assign alloys via PCA, but that important corrections for detector drift and scaling must be performed in order to achieve valid results.
Potassium titanyl phosphate crystals in both x-cut and z-cut were irradiated with 185 MeV Au ions. The morphology of the resulting ion tracks was investigated using small angle x-ray scattering (SAXS), transmission electron microscopy (TEM), and atomic force microscopy (AFM). SAXS measurements indicate the presence of cylindrical ion tracks with abrupt boundaries and a density contrast of 1 ± 0.5% compared to the surrounding matrix, consistent with amorphous tracks. The track radius depends on the crystalline orientation, with 6.0 ± 0.1 nm measured for ion tracks along the x-axis and 6.3 ± 0.1 nm for those along the z-axis. TEM images in both cross-section and plan-view show amorphous ion tracks with radii comparable to those determined from SAXS analysis. The protruding hillocks covering the sample surface detected by AFM are consistent with a lower density of the amorphous material within the ion tracks compared to the surrounding matrix. Simulations using an inelastic thermal-spike model indicate that differences in the thermal conductivity along the z- and x-axis can partially explain the different track radii along these directions.
High-temperature X-ray diffraction with concurrent gas chromatography (GC) was used to study cobalt disulfide cathode pellets disassembled from thermal batteries. When CoS2 cathode materials were analyzed in an air environment, oxidation of the K(Br, Cl) salt phase in the cathode led to the formation of K2SO4 that subsequently reacted with the pyrite-type CoS2 phase leading to cathode decomposition between ~260 and 450 °C. Independent thermal analysis experiments, i.e. simultaneous thermogravimetric analysis/differential scanning calorimetry/mass spectrometry (MS), augmented the diffraction results and support the overall picture of CoS2 decomposition. Both gas analysis measurements (i.e. GC and MS) from the independent experiments confirmed the formation of SO2 off-gas species during breakdown of the CoS2. In contrast, characterization of the same cathode material under inert conditions showed the presence of CoS2 throughout the entire temperature range of analysis.
There has been some confusion in the published literature concerning the structure of Metastudtite (UO2)O2(H2O)2 where differing unit cells and space groups have been cited for this compound. Owing to the absence of a refined structure for Metastudtite, Weck et al. (2012) have documented a first-principles study of Metastudtite using density functional theory (DFT). Their model presents the structure of Metastudtite as an orthorhombic (space group Pnma) structure with lattice parameters of a = 8.45, b = 8.72, and c = 6.75 Å. A Powder Diffraction File (PDF) database entry has been allocated for this hypothetical Metastudtite phase based on the DFT modeling (see 01-081-9033) and aforementioned Dalton Trans. manuscript. We have obtained phase pure powder X-ray diffraction data for Metastudtite and have confirmed the model of Weck et al. via Rietveld refinement (see Figure 1). Structural refinement of this powder diffraction dataset has yielded updated refined parameters. The new cell has been determined as a = 8.411(1), b = 8.744(1), and c = 6.505(1) Å; cell volume = 478.39 Å3. There are only subtle differences between the refined structure and that of the first-principles model derived from DFT. Notably, the b-axis is significantly contracted in the final refinement as compared with DFT. There were also subtle changes to the U1, O1, and O3 atom positions. Tabulated powder diffraction data (d's and I's) for the Metastudtite have been derived from the refined model and these new values can serve to augment the PDF entry 01-081-9033 with a more updated entry based on observed X-ray powder diffraction data.
Twelve accelerator mass spectrometry (AMS) radiocarbon dates from the shell-matrix site of Canímar Abajo (Matanzas, Cuba) are reported. Eleven were obtained directly from human bone collagen in burials and one was obtained from charcoal recovered from a burial context. The site stratigraphy presents two episodes of burial activity separated by a shell midden layer. The AMS dates fall into two compact clusters that correlate remarkably well with the stratigraphy. The older burial dates to between 1380–800 cal BC (2σ) and the younger one to between cal AD 360–950 (2σ). The AMS dates are compared to eight conventional 14C dates previously obtained on shell and charcoal. One of the conventional dates on charcoal (5480–5380 cal BC; 2σ) has been reported as the oldest 14C date in the Caribbean region; its context and reliability are clarified. The suite of AMS dates provides one of the most reliable chronometric dating of a cultural context during this timeframe in Cuba. The correlation of 14C and stratigraphy establishes a solid chronology for investigating the important economic and ritual features of Canímar Abajo.
The structure of La2LiTaO6 has been derived from the powder X-ray powder diffraction (XRD) data. La2LiTaO6 is monoclinic with unit-cell parameters a = 5.621(1) Å, b = 5.776(1) Å, c = 7.954(2) Å, β = 90.34(2)°, space group P21/n (14), and Z = 2. The structure of La2LiTaO6 is an ordered perovskite with alternating Li and Ta octahedra. A new set of powder XRD data (d-spacing and intensity listing) has been generated to replace entry 00-039-0897 within the Powder Diffraction File. The newly elucidated structural data for La2LiTaO6 shall facilitate quantitative analysis of this impurity phase which is often observed during synthesis of the fast-ion conductor phase Li5La3Ta2O12.
A simple hydrothermal route to the eulytite phase of bismuth germanium oxide (E-BGO: Bi4(GeO4)3) that required no post-processing has been developed. The E-BGO material was isolated from a mixture of bismuth nitrate pentahydrate and a slight excess of germanium oxide in water under hydrothermal conditions (185 °C for 24 h). The resultant materials were characterized by powder x-ray diffraction, scanning electron microscopy, transmission electron microscopy, and luminescence measurements to verify the particle's phase (eulytite), morphology, size, and response to a variety of excitation energy sources, respectively. Photoluminescence spectroscopic response from E-BGO pellets indicated that the samples exhibited a strong emission peak consistent with an x-ray induced luminescence of a E-BGO single crystal (500 nm excited at 285 nm). Cathodoluminescent properties of the E-BGO displayed a broadband spectrum with a maximum at 487 nm. The growth process was consistent with a standard Oswald ripening and LaMer growth processes.
The monoclinic-to-tetragonal phase transition (~70 °C) in vanadium dioxide (VO2) strongly impacts the infrared properties, which enables its use in applications such as smart window devices. Synthesis of VO2 can be challenging due to the variability of vanadium oxide phases that may be formed. We have employed high-temperature X-ray diffraction (HTXRD) to monitor the reaction process of vanadium oxide precursor powders to form the desired tetragonal VO2 phase. Single-phase tetragonal VO2 was formed within 30 min at 420 °C in flowing N2 gas (~50 ppm O2). The monoclinic-to-tetragonal phase transformation was observed via HTXRD at ~70 °C with the typical ~10 °C hysteresis (i.e. approached from above or below the transition).
Using photometry at just two wavelengths it is possible to fit a blackbody to the spectrum of infrared excess that is the signature of a debris disc. From this the location of the dust can be inferred. However, it is well known that dust in debris discs is not a perfect blackbody. By resolving debris discs we can find the actual location of the dust and compare this to that inferred from the blackbody fit. Using the Herschel Space Observatory we resolved many systems as part of the DEBRIS survey. Here we discuss a sample of 9 discs surrounding A stars and find that the discs are actually located between 1 and 2.5 times further from their star than predicted by blackbody fits to the spectral energy distribution (SED). The variation in this ratio is due to differences in stellar luminosities, location of the dust, size distribution and composition of the dust.
A new Matlab-based software suite called Tilt-A-Whirl has been applied to XRD data from textured gold films electro-deposited onto nickel substrates. The software routines facilitate phase identification, texture analysis via pole figure visualization, and macrostrain determination. The use of principal component analysis with multivariate curve resolution (PCA/MCR) revealed the extraction of texture components. The unusual hardness properties of one Au film (deposited from a 30% gold depleted BDT-200 bath) were found to be dependent on the (210) out-of-plane preferred orientation of the polycrystalline gold film. The progressive nucleation of Au crystallites during electro-plating has been tied to improved hardness properties of this film.