Multi-GeV Electron Acceleration in Wakefields Strongly Driven by Oversized Laser Spots.

Experiments were performed on laser wakefield acceleration in the highly nonlinear regime. With laser powers P<250 TW and using an initial spot size larger than the matched spot size for guiding, we were able to accelerate electrons to energies E_{max}>2.5 GeV, in fields exceeding 500 GV m^{-1}, with more than 80 pC of charge at energies E>1 GeV. Three-dimensional particle-in-cell simulations show that using an oversized spot delays injection, avoiding beam loss as the wakefield undergoes length oscillation. This enables injected electrons to remain in the regions of highest accelerating fields and leads to a doubling of energy gain as compared to results from using half the focal length with the same laser.

Non-invasive in-utero quantification of vascular reactivity in human placenta.

OBJECTIVE: Placental vascular reactivity (PlVR) indicates the ability of the placental vasculature to match blood supply to fetal demand. Many pregnancy disorders alter the characteristics of PlVR, resulting in suboptimal oxygen delivery, although current understanding is limited by the lack of non-invasive, repeatable methods to measure PlVR in utero. Our objective was to quantify PlVR by measuring the placental response to transient changes in maternal carbon dioxide (CO2) using blood-oxygen-level-dependent (BOLD) magnetic resonance imaging (MRI). We hypothesized that PlVR will increase with gestational age to meet the changing demands of a growing fetus, and that PlVR will be driven by a maternal response to changes in CO2 concentration. METHODS: This was a cross-sectional study of 35 women with a healthy singleton pregnancy, of whom 31 were included in the analysis. The median gestational age was 32.6 (range, 22.6-38.4) weeks. Pregnant women were instructed to follow audiovisual breathing cues during a MRI scan. Maternal end-tidal CO2 (EtCO2) was measured concurrently with resting placental BOLD MRI for a total of 7-8 min. Preprocessing of magnetic resonance images consisted of manual delineation of placental anatomy and motion correction. In each placental voxel, vascular reactivity was computed using a coherence-weighted general linear model between MRI signal and EtCO2 stimulus. Global PlVR was computed as the mean of voxel-wise PlVR values across the placenta. RESULTS: PlVR, quantified by the placental response to induced, transient changes in maternal CO2, was consistently measured in utero using BOLD MRI. PlVR increased non-linearly with advancing gestational age (P < 0.001) and was higher on the fetal side of the placenta. PlVR was associated positively with fetal brain volume after accounting for gestational age. PlVR did not show any significant associations with maternal characteristics. CONCLUSIONS: We present, for the first time, a non-invasive paradigm to quantify PlVR in ongoing human pregnancies without the use of exogenous gases or contrast agents. Our findings suggest that PlVR is driven by a fetal response to changes in maternal CO2. Ease of translation to the clinical setting makes PlVR a promising biomarker for the identification and management of high-risk pregnancies. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Can generative AI improve the readability of patient education materials at a radiology practice?

AIM: This study evaluated the readability of existing patient education materials and explored the potential of generative AI tools, such as ChatGPT-4 and Google Gemini, to simplify these materials to a sixth-grade reading level, in accordance with guidelines. MATERIALS AND METHODS: Seven patient education documents were selected from a major radiology group. ChatGPT-4 and Gemini were provided the documents and asked to reformulate to target a sixth-grade reading level. Average reading level (ARL) and proportional word count (PWC) change were calculated, and a 1-sample t-test was conducted (p=0.05). Three radiologists assessed the materials on a Likert scale for appropriateness, relevance, clarity, and information retention. RESULTS: The original materials had an ARL of 11.72. ChatGPT ARL was 7.32 ± 0.76 (6/7 significant) and Gemini ARL was 6.55 ± 0.51 (7/7 significant). ChatGPT reduced word count by 15% ± 7%, with 95% retaining at least 75% of information. Gemini reduced word count by 33% ± 7%, with 68% retaining at least 75% of information. ChatGPT outputs were more appropriate (95% vs. 57%), clear (92% vs. 67%), and relevant (95% vs. 76%) than Gemini. Interrater agreement was significantly different for ChatGPT (0.91) than for Gemini (0.46). CONCLUSION: Generative AI significantly enhances the readability of patient education materials, which did not achieve the recommended sixth-grade ARL. Radiologist evaluations confirmed the appropriateness and relevance of the AI-simplified texts. This study emphasizes the capabilities of generative AI tools and the necessity for ongoing expert review to maintain content accuracy and suitability.

SubQ-Sim: A Subcutaneous Physiologically Based Biopharmaceutics Model. Part 1: The Injection and System Parameters.

PURPOSE: To construct a detailed mechanistic and physiologically based biopharmaceutics model capable of predicting 1) device-formulation-tissue interaction during the injection process and 2) binding, degradation, local distribution, diffusion, and drug absorption, following subcutaneous injection. This paper is part of a series and focusses on the first aspect. METHODS: A mathematical model, SubQ-Sim, was developed incorporating the details of the various substructures within the subcutaneous environment together with the calculation of dynamic drug disposition towards the lymph ducts and venous capillaries. Literature was searched to derive key model parameters in healthy and diseased subjects. External factors such as body temperature, exercise, body position, food or stress provide a means to calculate the impact of "life events" on the pharmacokinetics of subcutaneously administered drugs. RESULTS: The model predicts the tissue backpressure time profile during the injection as a function of injection rate, volume injected, solution viscosity, and interstitial fluid viscosity. The shape of the depot and the concentrations of the formulation and proteins in the depot are described. The model enables prediction of formulation backflow following premature needle removal and the resulting formulation losses. Finally, the effect of disease (type 2 diabetes) or the presence of recombinant human hyaluronidase in the formulation on the injection pressure, are explored. CONCLUSIONS: This novel model can successfully predict tissue back pressure, depot dimensions, drug and protein concentration and formulation losses due to incorrect injection, which are all important starting conditions for predicting drug absorption from a subcutaneous dose. The next article will describe the absorption model and validation against clinical data.

A review of the nematode assemblage of the Australian bandicoot, Isoodon macrourus (Peramelidae), from material held in the South Australian Museum with the description of Sprattellus cassonei n. sp. (Mackerrastrongylidae).

A total of 235 vials of nematodes held in the Australian Helminthological Collection of the South Australian Museum from 125 individuals of Isoodon macrourus were examined. The nematode assemblage of I. macrourus, comprising 12 families, including 16 genera and 23 identified species, was compared with the sympatric bandicoot species Perameles nasuta, 20 identified species (Sorensen's index of similarity 0.56) and P. pallescens, 12 identified species (Sorensen's index 0.51). Sprattellus cassonei n. sp. is distinguished from its congeners by having a synlophe with 7-8 ridges with the anterior ventral ridges interrupted, the morphology of the dorsal ray and the branching of the spicule tips. A single male specimen identified as Linstowinema sp. 1. is characterised by seven circles of body hooks, the oesophagus terminating at the level of the seventh circle and robust scale-like spines on the posterior ventral body. A complete description of the species will require additional material, including females. Difficulties in identifying individuals of the genus Mackerrastrongylus to species level are discussed. Overall similarities in the nematode assemblages of the three bandicoot hosts are likely due to shared relationships and similar behaviours.

"Treat Them Like Human Beings": Black Children's Experiences with Racial Microaggressions in Early Childhood Education During COVID-19.

This study investigated microaggressions Black children experienced in early childhood education during the pandemic. Using racial microaggressions as a framework, we sought to gain insights into these experiences through counter-narratives from parents of Black children. Parents provided unique insights into their children's experiences, giving voice to their daily realities in early learning contexts. This article focuses on how Black children are treated with second-class student status. Black children being positioned with second-class status was the most predominant theme from this work during the pandemic. This is noteworthy, as few studies have considered how the pandemic uniquely shaped Black children's educational realities.

Raman Interferometry between Autoionizing States to Probe Ultrafast Wave-Packet Dynamics with High Spectral Resolution.

Photoelectron interferometry with femtosecond and attosecond light pulses is a powerful probe of the fast electron wave-packet dynamics, albeit it has practical limitations on the energy resolution. We show that one can simultaneously obtain both high temporal and spectral resolution by stimulating Raman interferences with one light pulse and monitoring the modification of the electron yield in a separate step. Applying this spectroscopic approach to the autoionizing states of argon, we experimentally resolved its electronic composition and time evolution in exquisite detail. Theoretical calculations show remarkable agreement with the observations and shed light on the light-matter interaction parameters. Using appropriate Raman probing and delayed detection steps, this technique enables highly sensitive probing and control of electron dynamics in complex systems.

In Situ Measurement of Electron Energy Evolution in a Laser-Plasma Accelerator.

We report on a novel, noninvasive method applying Thomson scattering to measure the evolution of the electron beam energy inside a laser-plasma accelerator with high spatial resolution. The determination of the local electron energy enabled the in-situ detection of the acting acceleration fields without altering the final beam state. In this Letter we demonstrate that the accelerating fields evolve from (265±119) GV/m to (9±4) GV/m in a plasma density ramp. The presented data show excellent agreement with particle-in-cell simulations. This method provides new possibilities for detecting the dynamics of plasma-based accelerators and their optimization.

Heritable anisotropy associated with cognitive impairments among patients with schizophrenia and their non-psychotic relatives in multiplex families.

BACKGROUND: To test the functional implications of impaired white matter (WM) connectivity among patients with schizophrenia and their relatives, we examined the heritability of fractional anisotropy (FA) measured on diffusion tensor imaging data acquired in Pittsburgh and Philadelphia, and its association with cognitive performance in a unique sample of 175 multigenerational non-psychotic relatives of 23 multiplex schizophrenia families and 240 unrelated controls (total = 438). METHODS: We examined polygenic inheritance (h2r) of FA in 24 WM tracts bilaterally, and also pleiotropy to test whether heritability of FA in multiple WM tracts is secondary to genetic correlation among tracts using the Sequential Oligogenic Linkage Analysis Routines. Partial correlation tests examined the correlation of FA with performance on eight cognitive domains on the Penn Computerized Neurocognitive Battery, controlling for age, sex, site and mother's education, followed by multiple comparison corrections. RESULTS: Significant total additive genetic heritability of FA was observed in all three-categories of WM tracts (association, commissural and projection fibers), in total 33/48 tracts. There were significant genetic correlations in 40% of tracts. Diagnostic group main effects were observed only in tracts with significantly heritable FA. Correlation of FA with neurocognitive impairments was observed mainly in heritable tracts. CONCLUSIONS: Our data show significant heritability of all three-types of tracts among relatives of schizophrenia. Significant heritability of FA of multiple tracts was not entirely due to genetic correlations among the tracts. Diagnostic group main effect and correlation with neurocognitive performance were mainly restricted to tracts with heritable FA suggesting shared genetic effects on these traits.

From laboratory tests to field trials: a review of cathodic protection and microbially influenced corrosion.

Cathodic protection (CP), an electrochemical method for managing corrosion, is widely used in many industries in both marine and buried environments. However, literature surrounding cathodic protection and its ability to prevent microbially influenced corrosion (MIC) is mixed. This review describes the mechanics of CP, how CP may influence MIC, and collates and summarises tests on CP and MIC reported in literature. The aim of the review is to identify any trends and knowledge gaps requiring further study. While the outcomes of CP testing are generally mixed, some trends can be seen and, overall, MIC is detrimental to the protective effects of CP, with CP being less effective when used according to current international standards. Tests conducted in the field or with mix communities of microbes showed that CP could be effective at preventing MIC, while tests with sulfate-reducing bacteria generally proved CP to be highly ineffective. It was commonly seen that the effectiveness of CP can be improved by increasing polarization, to potentials as low as -1000 mV (Ag/AgCl). However, a balance does need to be met via careful monitoring to ensure negative side effects of over protection do not become a major problem.

Cold sensing by NaV1.8-positive and NaV1.8-negative sensory neurons.

The ability to detect environmental cold serves as an important survival tool. The sodium channels NaV1.8 and NaV1.9, as well as the TRP channel Trpm8, have been shown to contribute to cold sensation in mice. Surprisingly, transcriptional profiling shows that NaV1.8/NaV1.9 and Trpm8 are expressed in nonoverlapping neuronal populations. Here we have used in vivo GCaMP3 imaging to identify cold-sensing populations of sensory neurons in live mice. We find that ∼80% of neurons responsive to cold down to 1 °C do not express NaV1.8, and that the genetic deletion of NaV1.8 does not affect the relative number, distribution, or maximal response of cold-sensitive neurons. Furthermore, the deletion of NaV1.8 had no observable effect on transient cold-induced (≥5 °C) behaviors in mice, as measured by the cold-plantar, cold-plate (5 and 10 °C), or acetone tests. In contrast, nocifensive-like behavior to extreme cold-plate stimulation (-5 °C) was completely absent in mice lacking NaV1.8. Fluorescence-activated cell sorting (FACS) and subsequent microarray analysis of sensory neurons activated at 4 °C identified an enriched repertoire of ion channels, which include the Trp channel Trpm8 and potassium channel Kcnk9, that are potentially required for cold sensing above freezing temperatures in mouse DRG neurons. These data demonstrate the complexity of cold-sensing mechanisms in mouse sensory neurons, revealing a principal role for NaV1.8-negative neurons in sensing both innocuous and acute noxious cooling down to 1 °C, while NaV1.8-positive neurons are likely responsible for the transduction of prolonged extreme cold temperatures, where tissue damage causes pan-nociceptor activation.

Advances in colonic motor complexes in mice.

The primary functions of the gastrointestinal (GI) tract are to absorb nutrients, water, and electrolytes that are essential for life. This is accompanied by the capability of the GI tract to mix ingested content to maximize absorption and effectively excrete waste material. There have been major advances in understanding intrinsic neural mechanisms involved in GI motility. This review highlights major advances over the past few decades in our understanding of colonic motor complexes (CMCs), the major intrinsic neural patterns that control GI motility. CMCs are generated by rhythmic coordinated firing of large populations of myenteric neurons. Initially, it was thought that serotonin release from the mucosa was required for CMC generation. However, careful experiments have now shown that neither the mucosa nor endogenous serotonin are required, although, evidence suggests enteroendocrine (EC) cells modulate CMCs. The frequency and extent of propagation of CMCs are highly dependent on mechanical stimuli (circumferential stretch). In summary, the isolated mouse colon emerges as a good model to investigate intrinsic mechanisms underlying colonic motility and provides an excellent preparation to explore potential therapeutic agents on colonic motility, in a highly controlled in vitro environment. In addition, during CMCs, the mouse colon facilitates investigations into the emergence of dynamic assemblies of extensive neural networks, applicable to the nervous system of different organisms.

High Taxonomic Diversity in Ship Bilges Presents Challenges for Monitoring Microbial Corrosion and Opportunity To Utilize Community Functional Profiling.

One of the key areas in which microbially influenced corrosion (MIC) has been found to be a problem is in the bilges of maritime vessels. To establish effective biological monitoring protocols, baseline knowledge of the temporal and spatial biological variation within bilges, as well as the effectiveness of different sampling methodologies, is critical. We used 16S rRNA gene metabarcoding of pelagic and sessile bacterial communities from ship bilges to assess the variation in bilge bacterial communities to determine how the inherent bilge diversity could guide or constrain biological monitoring. Bilge communities exhibited high levels of spatial and temporal variation, with >80% of the community able to be turned over in the space of 3 months, likely due to disturbance events such as cleaning and maintenance. Sessile and pelagic communities within a given bilge were also inherently distinct, with dominant exact sequence variants (ESVs) rarely shared between the two. Taxa containing KEGG orthologies (KOs) associated with dissimilatory sulfate reduction and biofilm production, functions typically associated with MIC, were generally more prevalent in sessile communities. Collectively, our findings indicate that neither bilge water nor an unaffected bilge from within the same vessel would constitute an appropriate reference community for MIC diagnosis. Optimal sampling locations and strategies that could be incorporated into a standardized method for monitoring bilge biology in relation to MIC were identified. Finally, taxonomic and functional comparisons of bilge diversity highlight the potential of functional approaches in future biological monitoring of MIC and MIC mitigation strategies in general. IMPORTANCE Microbially influenced corrosion (MIC) has been estimated to contribute 20 to 50% of the costs associated with corrosion globally. Diagnosis and monitoring of MIC are complex problems requiring knowledge of corrosion rates, corrosion morphology, and the associated microbiology to distinguish MIC from abiotic corrosion processes. Historically, biological monitoring of MIC utilized a priori knowledge to monitor sulfate-reducing bacteria; however, it is becoming widely accepted that a holistic or community-level understanding of corrosion-associated microbiology is needed for MIC diagnosis and monitoring. Before biology associated with MIC attack can be identified, standardized protocols for sampling and monitoring must be developed. The significance of our research is in contributing to the development of robust and repeatable sampling strategies of bilges, which are required for the development of standardized biological monitoring methods for MIC. We achieve this via a biodiversity survey of bilge communities and by comparing taxonomic and functional variation.

Energy-Spread Preservation and High Efficiency in a Plasma-Wakefield Accelerator.

Energy-efficient plasma-wakefield acceleration of particle bunches with low energy spread is a promising path to realizing compact free-electron lasers and particle colliders. High efficiency and low energy spread can be achieved simultaneously by strong beam loading of plasma wakefields when accelerating bunches with carefully tailored current profiles [M. Tzoufras et al., Phys. Rev. Lett. 101, 145002 (2008)PRLTAO0031-900710.1103/PhysRevLett.101.145002]. We experimentally demonstrate such optimal beam loading in a nonlinear electron-driven plasma accelerator. Bunches with an initial energy of 1 GeV were accelerated by 45 MeV with an energy-transfer efficiency of (42±4)% at a gradient of 1.3 GV/m while preserving per-mille energy spreads with full charge coupling, demonstrating wakefield flattening at the few-percent level.

Dynamics and risk of transmission of bovine tuberculosis in the emerging dairy regions of Ethiopia.

The Ethiopian government has several initiatives to expand and intensify the dairy industry; however, the risk of bovine tuberculosis (bTB) spread is a challenge. To assess the rate of expansion and risk factors for transmission of bTB within-herds, we carried out a repeated cross-sectional survey at two time points, 2016/17 and 2018, in three regional cities, namely, Gondar, Hawassa and Mekelle, representing the emerging dairy belts of Ethiopia. The total number of herds involved was 128, comprising an average of 2303 cattle in each round. The Single Intradermal Comparative Cervical Tuberculin (SICCT) test was used to identify reactor status and data on herd-level risk factors were collected using a structured questionnaire. In the first survey, the apparent prevalence of bTB, as measured by the SICCT test, was 4.5% (95% CI 3.7-5.4%) at the individual animal-level and 24% (95% CI 17.5-32%) at the herd-level. There was no statistically significant change in the overall apparent prevalence or regional distribution at the second survey, consistent with the infection being endemic. The incidence rate was estimated at 3.6 (95% CI 2.8-4.5) and 6.6 (95% CI 3.0-12.6) cases/100 cattle (or herd)-years at the animal- and herd-levels, respectively. Risk factors significantly associated with the within-herd transmission of bTB were age group and within-herd apparent prevalence at the start of the observation period. We noted that farmers voluntarily took steps to remove reactor cattle from their herds as a consequence of the information shared after the first survey. Removal of reactors between surveys was associated with a reduced risk of transmission within these herds. However, with no regulatory barriers to the sale of reactor animals, such actions could potentially lead to further spread between herds. We therefore advocate the importance of setting up regulations and then establishing a systematic bTB surveillance programme to monitor the impact prior to implementing any control measures in Ethiopia.

Inactivation of Bacillus anthracis and Bacillus atrophaeus spores on different surfaces with ultraviolet light produced with a low-pressure mercury vapor lamp or light emitting diodes.

AIMS: To obtain quantitative efficacy data of two ultraviolet light (UVC) technologies for surface inactivation of Bacillus anthracis Ames and Bacillus atrophaeus spores. METHODS AND RESULTS: Spores were deposited onto test coupons and controls of four different materials, via liquid suspension or aerosol deposition. The test coupons were then exposed to UVC light from either a low-pressure mercury vapor lamp or a system comprised of light emitting diodes, with a range of dosages. Positive controls were held at ambient conditions and not exposed to UVC light. Following exposure to UVC, spores were recovered from the coupons and efficacy was quantified in terms of log10 reduction (LR) in the number of viable spores compared to that from positive controls. CONCLUSIONS: Decontamination efficacy varied by material and UVC dosage (efficacy up to 5·7 LR was demonstrated). There was no statistical difference in efficacy between the two species or between inoculation methods. Efficacy improved for the LED lamp at lower relative humidity, but this effect was not observed with the mercury vapor lamp. SIGNIFICANCE AND IMPACT OF THE STUDY: This study will be useful in determining whether UVC could be used for the inactivation of B. anthracis spores on different surface types.

What factors are associated with food security among recently arrived refugees resettling in high-income countries? A scoping review.

OBJECTIVE: Refugees are vulnerable to food insecurity (FI). This is attributable to a combination of inequitable social determinants and cultural differences. In 2019, 92 % of refugee resettlement (host country provides residency/citizenship) occurred in high-income countries, but little is known about the factors impacting their food security status in this setting. The review's objective was to therefore thematically identify factors affecting food security among refugees resettling in high-income countries. DESIGN: This review was based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews. Between May-July 2020 and February 2021, peer-reviewed studies focused on FI, and published in English from 2000-2020, were searched on Medline, CINAHL, Scopus, Informit, PsychArticles, Proquest and EmBase. SETTING: Only studies set in high-income countries were included. PARTICIPANTS: Fifty percent or more of study participants had to be refugees who had resettled within 5 years. RESULTS: Twenty studies from six high-income countries were included. Culturally based food practices and priorities, confidence in navigating local foodways and transport, level of community connections and capabilities in local language and food preparation were key themes associated with food security. CONCLUSIONS: Utilising the four themes of culture, confidence, community and capabilities, there is an opportunity to improve the cultural sensitivity of measurement tools, develop understanding of how community-based resources (such as social capital) can be leveraged as food security buffers and modify existing food security initiatives to better serve refugee needs.

Osteoarthritis-related nociceptive behaviour following mechanical joint loading correlates with cartilage damage.

OBJECTIVE: In osteoarthritis (OA), the pain-structure relationship remains complex and poorly understood. Here, we used the mechanical joint loading (MJL) model of OA to investigate both knee pathology and nociceptive behaviour. DESIGN: MJL was used to induce OA in the right knees of 12-week-old male C57BL/6 mice (40 cycles, 9N, 3x/week for 2 weeks). Mechanical sensitivity thresholds and weight-bearing ratios were measured before loading and at weeks one, three and six post-loading. At these time points, separate groups of loaded and non-loaded mice (n = 12/group) were sacrificed, joints collected, and fur corticosterone levels measured. µCT analyses of subchondral bone integrity was performed before joint sections were prepared for nerve quantification, cartilage or synovium grading (scoring system from 0 to 6). RESULTS: Loaded mice showed increased mechanical hypersensitivity paired with altered weight-bearing. Initial ipsilateral cartilage lesions 1-week post-loading (1.8 ± 0.4) had worsened at weeks three (3.0 ± 0.6, CI = -1.8-0.6) and six (2.8 ± 0.4, CI = -1.6-0.4). This increase in lesion severity correlated with mechanical hypersensitivity development (correlation; 0.729, P = 0.0071). Loaded mice displayed increased synovitis (3.6 ± 0.5) compared to non-loaded mice (1.5 ± 0.5, CI = -2.2-0.3) 1-week post-loading which returned to normal by weeks three and six. Similarly, corticosterone levels were only increased at week one post-loading (0.21 ± 0.04 ng/mg) compared to non-loaded controls (0.14 ± 0.01 ng/mg, CI = -1.8-0.1). Subchondral bone integrity and nerve volume remained unchanged. CONCLUSIONS: Our data indicates that although the loading induces an initial stress reaction and local inflammation, these processes are not directly responsible for the nociceptive phenotype observed. Instead, MJL-induced allodynia is mainly associated with OA-like progression of cartilage lesions.

Physics of Nuclei: Key Role of an Emergent Symmetry.

We show through first-principles nuclear structure calculations that the special nature of the strong nuclear force determines highly regular patterns heretofore unrecognized in nuclei that can be tied to an emergent approximate symmetry. This symmetry is ubiquitous and mathematically tracks with a symplectic symmetry group. This, in turn, has important implications for understanding the physics of nuclei: we find that nuclei are made of only a few equilibrium shapes, deformed or not, with associated vibrations and rotations. It also opens the path for ab initio large-scale modeling of open-shell intermediate-mass nuclei without the need for renormalized interactions and effective charges.

Evaluation of altered environmental conditions as a decontamination approach for nonspore-forming biological agents.

AIMS: The purpose of this study was to evaluate the effects of altered environmental conditions on the persistence of Francisella tularensis bacteria and Venezuelan equine encephalitis virus (VEEV), on two material types. METHODS AND RESULTS: Francisella tularensis (F.t.) and VEEV were inoculated (c. 1 × 108 colony-forming units or PFU), dried onto porous and nonporous fomites (glass and paper), and exposed to combinations of altered environmental conditions ranging from 22 to 60°C and 30 to 75% relative humidity (RH). Viability of test organism was assessed after contact times ranging from 30 min to 10 days. Inactivation rates of F.t. and VEEV increased as both temperature and/or RH were increased. Greater efficacy was observed for paper as compared to glass for both test organisms. CONCLUSIONS: The use of elevated temperature and RH increased rate of inactivation for both organisms and greater than six log reduction was accomplished in as little as 6 h by elevating temperature to approximately 60°C. SIGNIFICANCE AND IMPACT OF THE STUDY: These results provide information for inactivation of nonspore-forming select agents using elevated temperature and humidity which may aid incident commanders following a biological contamination incident by providing alternative methods for remediation.