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Abstract The successful integration of graphene in future technologies, such as filtration and nanoelectronics, depends on the ability to introduce controlled nanostructured defects in graphene. In this work, Raman spectroscopy is used to investigate the induction of disorder in graphene via gallium ion beam bombardment. Two configurations of CVD-grown graphene samples are used: (i) graphene supported on a Si/SiO 2 substrate, and (ii) graphene suspended on porous TEM grids. It is observed that the supported graphene experiences more damage in response to lower beam doses than suspended graphene. This phenomenon is attributed to the behaviour of the energetic ions impinging the sample. In suspended graphene, the ions pass through the graphene membrane once and disperse to the atmosphere, while in supported graphene, the ions embed themselves in the substrate causing swelling and backscattering events, hence increasing the induced disorder. In supported graphene, the ratio between the Gaussian D and G peaks attributed to amorphous carbon, and the Lorentzian D and G peaks attributed to graphene, (I DG / I DL) and (I GG / I GL), are suggested to be used to quantify the degree of amorphization. The results are relevant to the development of nanostructured graphene-based filtration or desalination membranes, as well as for graphene-based nanoelectronics. Graphical abstract Unlabelled Image Highlights • Ion irradiation causes more damage in supported rather than suspended graphene. • Gaussian to Lorentzian G peak ratio can be used to quantify the degree of disorder. • Higher incidence angles of irradiation increase damage in suspended graphene. [ABSTRACT FROM AUTHOR]

Introduction: The role and timing of postoperative radiotherapy (PORT) in the management of retroperitoneal sarcoma (RPS) remains controversial.Method: This is a retrospective cohort review of patients undergoing curative resection for RPS at a single institution between January 2011 and July 2016. Patient selection was through the South Australian Soft Tissue Tumour Multidisciplinary Group (MDT) based at Royal Adelaide Hospital. An individualised approach, including assessment of resectability, histopathological grade and subtype, and radiotherapy considerations, was taken for each patient. Patients offered preoperative radiotherapy or palliation were excluded. A saline-filled spacer was inserted following operative resection. Radiotherapy commenced postoperatively. Patients underwent laparotomy to remove the device approximately 6 weeks post completion of PORT. Primary endpoints were technical feasibility, perioperative morbidity and radiation toxicity. Secondary endpoints were local recurrence (LR), distant recurrence (DR) and death.Results: During the study period, 40 patients with RPS were managed through the MDT. Twelve patients (ages 33-78) underwent PORT utilising spacers. Radiotherapy toxicity was reported in four patients and extensive adhesions observed in another four patients during spacer removal. Median follow-up was 35 months (range 4-60). Seven patients remain alive and disease free. Four patients developed LR, three developed DR. Three patients died; two with DR and one with LR. Two patients with recurrent/progressive disease are alive; one with DR and one with LR.Conclusion: Use of intraoperative spacers to facilitate PORT is feasible, with acceptable toxicity following resection of RPS. Patient selection for this approach remains to be determined. [ABSTRACT FROM AUTHOR]

Revealing the scattering behaviour of gas molecules on porous surfaces is essential to develop accurate boundary conditions for kinetic transport models that describe the gas dynamics in shale reservoirs. Here, we use high-fidelity molecular dynamics simulations to resolve the gas–surface interactions between methane molecules and realistic organic kerogen surfaces, and to assess the applicability of the widely used scattering kernels. Our results show that the tight matrix porosities have a negligible effect on the timescale and lengthscale of the scattering process, which can be considered instantaneous in time and local in space. Although reflected velocity distributions reveal that the common Maxwell, Cercignani–Lampis and Yamamoto scattering models fail to fully capture the scattering details of methane on kerogen, especially when the incident molecular speeds are high, the Maxwell model predicts best the reflected angular beam pattern and the overall reflected velocity distribution for rough kerogen surfaces. However, for low-speed impingement, more characteristic of shale applications, all scattering models give similar velocity distributions, which are driven by the high degree of gas–surface accommodation observed. We find that a Maxwell model with a calibrated tangential momentum accommodation coefficient, which approaches unity as the surface roughness increases to ∼ 2 nm , is enough to reproduce comparable velocity profiles and mass flow rates inside moderately confined kerogen mesopores. Deviations between the Maxwell model and our molecular simulations are only observed for highly rarefied transport problems, but this rarefaction lies beyond the realm of shale reservoir applications. This paper, therefore, reports the first scattering study on porous and rough kerogen surfaces, and demonstrates the applicability of the Maxwell model, which can be readily incorporated into gas kinetic solvers to predict the apparent permeability of shale with mesopore and macropore networks. [Display omitted] • Molecular simulations reveal the first methane beam scattering on kerogen samples. • The timescale and lengthscale of the scattering process are unaffected by porosity. • Complete gas–surface accommodation is a common feature for rough kerogen surfaces. • Scattering discrepancies were observed between molecular data and existing models. • Transport simulations reveal Maxwell model with a calibrated coefficient is feasible. [ABSTRACT FROM AUTHOR]

Aims: Several gastrointestinal motility diseases are associated with altered numbers of interstitial cells of Cajal (ICC), and testing for alterations in numbers of ICC has been proposed as one way to improve routine diagnosis in motility diseases. However, the protocols currently used to visualize ICC in formalin-fixed paraffin-embedded (FFPE) tissue using antibodies to CD117 have not been optimized for studying motility disorders. The aims of this study were therefore to determine the optimal protocol using FFPE tissue, determine normal values for ICC in non-neoplastic human colon, and compare results with those obtained using immunofluorescence (IF). Methods and results: Non-neoplastic tissue was collected from patients undergoing resection for colonic cancer and fixed for both light (FFPE) and IF testing. Sections were processed for standard immunohistochemistry using different primary antibodies in conjunction with variations in antigen retrieval [ethylenediamine tetraacetricacid (EDTA), citrate], antibody dilution, blocking and detection (Mach2, Mach3, Envision+). Best results were obtained with EDTA retrieval, the DAKO CD117 antibody and Mach3 detection. Conclusions: The optimized protocol presented improved CD117 detection in FFPE tissues and showed good concordance with overall localization of CD117-immunoreactive ICC as detected by IF. As such, this protocol may be more useful than current diagnostic procedures in motility disorders. [ABSTRACT FROM AUTHOR]

[Display omitted] • Molecular simulations reveal scaling law for local adsorption of methane in kerogen. • Pores less than 1 nm have significant adsorption capacity, impacted by size and pressure. • Porosity plays the key role in the scaling of adsorption inside the kerogen. • New percolation model proposed to predict adsorption isotherms in nano-porous media. • Percolation model only requires input of kerogen atoms and is scalable to experiments. Developing unconventional shale gas resource has increased rapidly in recent years. However, while methane adsorbed inside organic kerogen matter is a source of shale production, it is still not a fully understood process. Here, we use molecular simulations to investigate methane adsorption in local micropores that are less than 1 nm inside realistic kerogen samples. We find an exponential scaling law for the local pore adsorption capacity and rationalise the pore density with the effective pore diameter, reservoir pressure, and sample porosity. This scaling law is determined from four kerogen samples at different porosities, each taken from a different shale reservoir, which have been experimentally validated in previous work. We find that pores closer to methane's diameter are responsible for ~ 20% of the adsorption inside the sample and it is these small pores and lower pressures that dictate the largest adsorption capacity inside kerogen. Predictions of adsorption isotherms from properties of the kerogen structures are now possible using a proposed numerical percolation model by means of this scaling law. Adsorption predictions using our model show remarkably good agreement with molecular dynamics results in this work and isotherms in the literature, at a fraction of the computational cost. This work opens up a new route for determining adsorption isotherms of dense porous media from knowledge about their local pore structure, and can be scaled efficiently to support experimental campaigns, where molecular simulations would be intractable. [ABSTRACT FROM AUTHOR]

• Boundary-layer separation and reattachment is identified with IR thermography. • Classical scaling analyses for separation length apply to a cone/flare geometry. • Peak heating scales with the inviscid density ratio across the separation shock. Time-resolved surface temperature measurements have been carried out on a 7 ° half-angle circular cone/flare model in the Air Force Research Laboratory's Mach-6 Ludwieg Tube using infrared thermography. Measurements were performed at zero angle of attack on a total of 16 different nose bluntness/flare angle geometries at three different freestream unit Reynolds numbers. The boundary layer entering the interaction region was turbulent for the two sharper nosetips and laminar for the two blunter nosetips. Stanton-number contours and profiles were used to investigate the effect of nose bluntness, flare angle, and freestream unit Reynolds number on the length of boundary-layer separation and the peak heating achieved upon reattachment. The classical scaling analyses of Souverein et al. and Hung & Barnett for separation length and peak heating, respectively, have been extended for the use of axisymmetric cone/flare shock-wave/boundary-layer interactions. Scaling the peak heating with the density ratio across the separation shock wave, instead of the pressure ratio, significantly improves/simplifies the analysis. [ABSTRACT FROM AUTHOR]

Global temperatures will continue to rise due to climate change, with high temperature periods expected to increase in intensity, frequency, and duration. Infectious diseases, including vector-borne diseases such as dengue fever and malaria, waterborne diseases such as cholera, and foodborne diseases such as salmonellosis are influenced by temperature and other climatic variables, thus contributing to higher disease burden and associated healthcare costs, particularly in socioeconomically disadvantaged regions. Targeted efforts and investments are therefore needed to support low and middle income countries to prepare for and respond to the increasing infectious disease threats posed by rising temperatures. This can be facilitated by the development and refinement of robust disease and entomological surveillance and early warning systems with integration of climatic information that promote enhanced understanding of the geographic distribution of disease risk. To enhance healthcare workforce capacity and capability to respond to these public health threats, medical curricula and continuing professional education programmes for healthcare providers must include evidence based components on the impacts of climate change on infectious diseases., Competing Interests: Competing interests: We have read and understood the BMJ policy on declaration of interests and declare that we have no competing interests., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.)

The impact of nanoscale wall roughness on rarefied gas transport is widely acknowledged, yet the associated scattering dynamics largely remain elusive. In this paper, we develop a scattering kernel for surfaces having nanoscale roughness that distinctly characterizes the two major types of interactions between gas molecules and rough surfaces. Namely these are (a) the weak perturbations arising from the thermal motion of wall atoms, essentially gas-phonon collisions, which are captured by the well-established Cercignani-Lampis model, and (b) the hard collisions owing to the irregularities of the rough, static potential energy surface, which are generally described by the fully diffuse model. Drawing an analogy between wave-surface and gas-surface scattering, a pseudo Debye-Waller factor is incorporated into the modeling as a weighting coefficient to allow the transition between smooth and rough surface conditions. The proposed scattering kernel is validated through high-fidelity molecular dynamics simulations that are performed for systems with varying roughness, temperature, and gas-surface combinations. The results indicate that the model well captures the scattering dynamics of gas molecular beams impinging on surfaces at different velocities, specifically for the accommodation coefficients and reflection patterns. Additionally, in flow and heat transport cases, it accurately predicts macroscopic quantities such as velocity slip and temperature jumps across the range of tested conditions.

The interfacial thermal conductance at a solid/liquid interface ( G ) exhibits an exponential-to-linear crossover with increasing solid/liquid interaction strength, previously attributed to the relative strength of solid/liquid to liquid/liquid interactions. Instead, using a simple Lennard-Jones setup, our molecular simulations reveal that this crossover occurs due to the onset of solidification in the interfacial liquid at high solid/liquid interaction strengths. This solidification subsequently influences interfacial energy transport, leading to the crossover in G . We use the overlap between the spectrally decomposed heat fluxes of the interfacial solid and liquid to pinpoint when "solid-like energy transport" within the interfacial liquid emerges. We also propose a novel decomposition of G into (i) the conductance right at the solid/liquid interface and (ii) the conductance of the nanoscale interfacial liquid region. We demonstrate that the rise of solid-like energy transport within the interfacial liquid influences the relative magnitude of these conductances, which in turn dictates when the crossover occurs. Our results can aid engineers in optimizing G at realistic interfaces, critical to designing effective cooling solutions for electronics among other applications., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Published by American Chemical Society.)

Background: In 2020, a research group published five linear longitudinal models, predict Expanded Prostate Cancer Index Composite-26 (EPIC-26) scores post-treatment for radical prostatectomy, external beam radiotherapy and active surveillance collectively in US patients with localized prostate cancer., Methods: Our study externally validates the five prediction models for patient reported outcomes post-surgery for localised prostate cancer. The models' calibration, fit, variance explained and discrimination (concordance-indices) were assessed. Two Australian validation cohorts 1 and 2 years post-prostatectomy were constructed, consisting of 669 and 439 subjects, respectively (750 in total). Patient reported function in five domains post-prostatectomy: sexual, bowel, hormonal, urinary incontinence and other urinary dysfunction (irritation/obstruction). Domain function was assessed using the EPIC-26 questionnaire., Results: 1 year post-surgery, R 2 was highest for the sexual domain (35%, SD = 0.02), lower for the bowel (21%, SD = 0.03) and hormone (15%, SD = 0.03) domains, and close to zero for urinary incontinence (1%, SD = 0.01) and irritation/obstruction (- 5%, SD = 0.04). Calibration slopes for these five models were 1.04 (SD = 0.04), 0.84 (SD = 0.06), 0.85 (SD = 0.06), 1.16 (SD = 0.13) and 0.45 (SD = 0.04), respectively. Calibration-in-the-large values were - 2.2 (SD = 0.6), 2.1 (SD = 0.01), 5.1 (SD = 0.1), 9.6 (SD = 0.9) and 4.0 (SD = 0.2), respectively. Concordance-indices were 0.73, 0.70, 0.70, 0.58 and 0.62, respectively (all had SD = 0.01). Mean absolute error and root mean square error were similar across the validation and development cohorts. The validation measures were largely similar at 2 years post-surgery., Conclusions: The sexual, bowel and hormone domain models validated well and show promise for accurately predicting patient reported outcomes in a non-US surgical population. The urinary domain models validated poorly and may require recalibration or revision., (© 2023. The Author(s).)

Nanobubble cavitation is advancing technologies in enhanced wastewater treatment, cancer therapy and diagnosis, and microfluidic cleaning. Current macroscale models predict that nanobubble oscillations should be isothermal, yet recent studies suggest that they are adiabatic with an associated increase in natural frequency, which becomes challenging when characterizing nanobubble sizes using ultrasound in experiments. We derive a new theoretical model that considers the nonideal nature of the nanobubble's internal gas phase and nonequilibrium effects, by employing the van der Waals (vdW) equation of state and implementing a temperature jump term at the liquid-gas interface, respectively, finding excellent agreement with molecular dynamics (MD) simulations. Our results reveal how adiabatic behavior could be erroneously interpreted when analyzing the thermal response of the gas using the commonly employed polytropic process and explain instead how nanobubble oscillations are physically closer to their isothermal limit.

Introduction: The costs of global warming are substantial. These include expenses from occupational illnesses and injuries (OIIs), which have been associated with increases during heatwaves. This study estimated retrospective and projected future heatwave-attributable OIIs and their costs in Australia., Materials and Methods: Climate and workers' compensation claims data were extracted from seven Australian capital cities representing OIIs from July 2005 to June 2018. Heatwaves were defined using the Excess Heat Factor. OIIs and associated costs were estimated separately per city and pooled to derive national estimates. Results were projected to 2030 (2016-2045) and 2050 (2036-2065)., Results: The risk of OIIs and associated costs increased during heatwaves, with the risk increasing during severe and particularly extreme heatwaves. Of all OIIs, 0.13% (95% empirical confidence interval [eCI]: 0.11-0.16%) were heatwave-attributable, equivalent to 120 (95%eCI:70-181) OIIs annually. 0.25% of costs were heatwave-attributable (95%eCI: 0.18-0.34%), equal to $AU4.3 (95%eCI: 1.4-7.4) million annually. Estimates of heatwave-attributable OIIs by 2050, under Representative Concentration Pathway [RCP]4.5 and RCP8.5, were 0.17% (95%eCI: 0.10-0.27%) and 0.23% (95%eCI: 0.13-0.37%), respectively. National costs estimates for 2030 under RCP4.5 and RCP8.5 were 0.13% (95%eCI: 0.27-0.46%) and 0.04% (95%eCI: 0.66-0.60), respectively. These estimates for extreme heatwaves were 0.04% (95%eCI: 0.02-0.06%) and 0.04% (95%eCI: 0.01-0.07), respectively. Cost-AFs in 2050 were, under RCP4.5, 0.127% (95%eCI: 0.27-0.46) for all heatwaves and 0.04% (95%eCI: 0.01-0.09%) for extreme heatwaves. Attributable fractions were approximately similar to baseline when assuming theoretical climate adaptation., Discussion: Heatwaves represent notable and preventable portions of preventable OIIs and economic burden. OIIs are likely to increase in the future, and costs during extreme heatwaves in 2030. Workplace and public health policies aimed at heat adaptation can reduce heat-attributable morbidity and costs., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Molecular simulations discover a new mode of dynamic wetting that manifests itself in the very earliest stages of spreading, after a droplet contacts a solid. The observed mode is a "rolling" type of motion, characterized by a contact angle lower than the classically assumed value of 180°, and precedes the conventional "sliding" mode of spreading. This motivates the development of a novel continuum framework that captures all modes of motion, allows the dominant physical mechanisms to be understood, and permits the study of larger droplets.

Many organisms in nature have evolved superhydrophobic surfaces that leverage water droplets to clean themselves. While this ubiquitous self-cleaning process has substantial industrial promise, experiments have so far been unable to comprehend the underlying physics. With the aid of molecular simulations, here we rationalize and theoretically explain self-cleaning mechanisms by resolving the complex interplay between particle-droplet and particle-surface interactions, which originate at the nanoscale. We present a universal phase diagram that consolidates (a) observations from previous surface self-cleaning experiments conducted at micro-to-millimeter length scales and (b) our nanoscale particle-droplet simulations. Counterintuitively, our analysis shows that an upper limit for the radius of the droplet exists to remove contaminants of a particular size. We are now able to predict when and how particles of varying scale (from nano-to-micrometer) and adhesive strengths are removed from superhydrophobic surfaces.

Rapid declines in unconventional shale production arise from the poorly understood interplay between gas transport and adsorption processes in microporous organic rock. Here, we use high-fidelity molecular dynamics (MD) simulations to resolve the time-varying adsorption of methane gas in realistic organic rock samples, known as kerogen. The kerogen samples derive from various geological shale fields with porosities ranging between 20% and 50%. We propose a kinetics sorption model based on a generalized solution of diffusive transport inside a nanopore to describe the adsorption kinetics in kerogen, which gives excellent fits with all our MD results, and we demonstrate it scales with the square of the length of kerogen. The MD adsorption time constants for all samples are compared with a simplified theoretical model, which we derive from the Langmuir isotherm for adsorption capacitance and the free-volume theory for steady, highly confined bulk transport. While the agreement with the MD results is qualitatively very good, it reveals that, in the limit of low porosity, the diffusive transport term dominates the characteristic time scale of adsorption, while the adsorption capacitance becomes important for higher pressures. This work provides the first data set for adsorption kinetics of methane in kerogen, a validated model to accurately describe this process, and a qualitative model that links adsorption capacitance and transport with the adsorption kinetics. Furthermore, this work paves the way to upscale interfacial adsorption processes to the next scale of gas transport simulations in mesopores and macropores of shale reservoirs.

The effect of turbulent wind-tunnel-wall boundary layers on density change measurements obtained with focused laser differential interferometry (FLDI) was studied using a detailed direct numerical simulation (DNS) of the wall from the Boeing/AFOSR Mach-6 Quiet Tunnel run in its noisy configuration. The DNS was probed with an FLDI model that is capable of reading in three-dimensional time-varying density fields and computing the FLDI response. Simulated FLDI measurements smooth the boundary-layer root-mean-square (RMS) profile relative to true values obtained by directly extracting the data from the DNS. The peak of the density change RMS measured by the FLDI falls within 20% of the true density change RMS. A relationship between local spatial density change and temporal density fluctuations was determined and successfully used to estimate density fluctuations from the FLDI measurements. FLDI measurements of the freestream fluctuations are found to be dominated by the off-axis tunnel-wall boundary layers for lower frequencies despite spatial suppression provided by the technique. However, low-amplitude (0.05%-5% of the mean density) target signals placed along the tunnel centerline were successfully measured over the noise of the boundary layers (which have RMS values of about 12% of the mean). Overall, FLDI was shown to be a useful technique for making quantitative turbulence measurements and to measure finite-width sinusoidal signals through turbulent boundary layers, but may not provide enough off-focus suppression to provide accurate freestream noise measurements, particularly at lower frequencies.

A 100 kHz krypton (Kr) tagging velocimetry (KTV) technique was demonstrated in a Mach-6 Ludwieg tube using a burst-mode laser-pumped optical parametric oscillator system. The single-beam KTV scheme at 212 nm produced an insufficient signal in this large hypersonic wind tunnel because of its low Kr seeding (≤5 % ), low static pressure (∼2.5 t o r r ), and long working distance (∼1 m ). To overcome these issues, a new scheme using two excitation beams was developed to enhance KTV performance. A 355 nm laser beam was combined with the 212 nm beam to promote efficient two-photon Kr excitation at 212 nm, and increase the probability of 2 + 1 resonant-enhanced multiphoton ionization by adding a 355 nm beam. A signal enhancement of approximately six times was obtained. Using this two-excitation beam approach, strong long-lasting KTV was successfully demonstrated at a 100 kHz repetition rate in a Mach-6 flow.

Ice accumulation on solid surfaces is a severe problem for safety and functioning of a large variety of engineering systems, and its control is an enormous challenge that influences the safety and reliability of many technological applications. The use of molecular dynamics (MD) simulations is popular, but as ice nucleation is a rare event when compared to simulation timescales, the simulations need to be accelerated to force ice to form on a surface, which affects the accuracy and/or applicability of the results obtained. Here, we present an alternative seeded MD simulation approach, which reduces the computational cost while still ensuring accurate simulations of ice growth on surfaces. In addition, this approach enables, for the first time, brute-force all-atom water simulations of ice growth on surfaces unfavorable for nucleation within MD timescales. Using this approach, we investigate the effect of surface wettability and structure on ice growth in the crucial surface-ice interfacial region. Our main findings are that the surface structure can induce a flat or buckled overlayer to form within the liquid, and this transition is mediated by surface wettability. The first overlayer and the bulk ice compete to structure the intermediate water layers between them, the relative influence of which is traced using density heat maps and diffusivity measurements. This work provides new understanding on the role of the surface properties on the structure and dynamics of ice growth, and we also present a useful framework for future research on surface icing simulations.

The collapse of cavitation bubbles often releases high-speed liquid jets capable of surface damage, with applications in drug delivery, cancer treatment, and surface cleaning. Spherical cap-shaped surface nanobubbles have previously been found to exist on immersed substrates. Despite being known nucleation sites for cavitation, their collapsing dynamics are currently unexplored. Here, we use molecular dynamics simulations to model the shock-induced collapse of different surface nanobubble sizes and contact angles. Comparisons are made with additional collapsing spherical nanobubble simulations near a substrate, to investigate the differences in their jet formation and resulting substrate pitting damage. Our main finding is that the pitting damage in the surface nanobubble simulations is greatly reduced, when compared to the spherical nanobubbles, which is primarily caused by the weaker jets formed during their collapse. Furthermore, the pit depths for surface nanobubble collapse do not depend on bubble size, unlike in the spherical nanobubble cases, but instead depend only on their contact angle. We also find a linear scaling relationship for all bubble cases between the final substrate damage and the peak pressure impulse at the impact centre, which can now be exploited to assess the relative damage in other computational studies of collapsing bubbles. We anticipate the more controlled surface-damage features produced by surface nanobubble cavitation jets will open up new applications in advanced manufacturing, medicine, and precision cleaning.

Femtosecond laser electronic excitation tagging (FLEET) velocimetry was used in the boundary layer of an ogive-cylinder model in a Mach-6 Ludwieg tube. One-dimensional velocity profiles were extracted from the FLEET signal in laminar boundary layers from pure N 2 flows at unit Reynolds numbers ranging from 3.4×10 6 / m to3.9×10 6 / m . The effects of model tip bluntness and the unit Reynolds number on the velocity profiles were investigated. The challenges and strategies of applying FLEET for direct boundary layer velocity measurement are discussed. The potential of utilizing FLEET velocimetry for understanding the dynamics of laminar and turbulent boundary layers in hypersonic flows is demonstrated.

Background: The adverse effects of heat on workers' health and work productivity are well documented. However, the resultant economic consequences and productivity loss are less understood. This review aims to summarize the retrospective and potential future economic burden of workplace heat exposure in the context of climate change., Methods: Literature was searched from database inception to October 2020 using Embase, PubMed, and Scopus. Articles were limited to original human studies investigating costs from occupational heat stress in English., Results: Twenty studies met criteria for inclusion. Eighteen studies estimated costs secondary to heat-induced labor productivity loss. Predicted global costs from lost worktime, in US$, were 280 billion in 1995, 311 billion in 2010 (≈0.5% of GDP), 2.4-2.5 trillion in 2030 (>1% of GDP) and up to 4.0% of GDP by 2100. Three studies estimated heat-related healthcare expenses from occupational injuries with averaged annual costs (US$) exceeding 1 million in Spain, 1 million in Guangzhou, China and 250,000 in Adelaide, Australia. Low- and middle-income countries and countries with warmer climates had greater losses as a proportion of GDP. Greater costs per worker were observed in outdoor industries, medium-sized businesses, amongst males, and workers aged 25-44 years., Conclusions: The estimated global economic burden of occupational heat stress is substantial. Climate change adaptation and mitigation strategies should be implemented to likely minimize future costs. Further research exploring the relationship between occupational heat stress and related expenses from lost productivity, decreased work efficiency and healthcare, and costs stratified by demographic factors, is warranted. Key messages. The estimated retrospective and future economic burden from occupational heat stress is large. Responding to climate change is crucial to minimize this burden. Analyzing heat-attributable occupational costs may guide the development of workplace heat management policies and practices as part of global warming strategies., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Ultrasonic surface vibration at high frequencies ( O (100 GHz)) can nucleate bubbles in a liquid within a few nanometres from a surface, but the underlying mechanism and the role of surface wettability remain poorly understood. Here, we employ molecular simulations to study and characterize this phenomenon, which we call acoustothermal nucleation. We observe that nanobubbles can nucleate on both hydrophilic and hydrophobic surfaces, and molecular energy balances are used to identify whether these are boiling or cavitation events. We rationalize the nucleation events by defining a physics-based energy balance, which matches our simulation results. To characterize the interplay between the acoustic parameters, surface wettability, and nucleation mechanism, we produce a regime map of nanoscopic nucleation events that connects observed nanoscale results to macroscopic experiments. This work provides insights to better design a range of industrial processes and clinical procedures such as surface treatments, mass spectroscopy, and selective cell destruction.

Surface nanobubbles have potential applications in the manipulation of nanoscale and biological materials, waste-water treatment, and surface cleaning. These spherically capped bubbles of gas can exist in stable diffusive equilibrium on chemically patterned or rough hydrophobic surfaces, under supersaturated conditions. Previous studies have investigated their long-term response to pressure variations, which is governed by the surrounding liquid's local supersaturation; however, not much is known about their short-term response to rapid pressure changes, i.e., their cavitation dynamics. Here, we present molecular dynamics simulations of a surface nanobubble subjected to an external oscillating pressure field. The surface nanobubble is found to oscillate with a pinned contact line, while still retaining a mostly spherical cap shape. The amplitude-frequency response is typical of an underdamped system, with a peak amplitude near the estimated natural frequency, despite the strong viscous effects at the nanoscale. This peak is enhanced by the surface nanobubble's high internal gas pressure, a result of the Laplace pressure. We find that accurately capturing the gas pressure, bubble volume, and pinned growth mode is important for estimating the natural frequency, and we propose a simple model for the surface nanobubble frequency response, with comparisons made to other common models for a spherical bubble, a constant contact angle surface bubble, and a bubble entrapped within a cylindrical micropore. This work reveals the initial stages of growth of cavitation nanobubbles on surfaces, common in heterogeneous nucleation, where classical models based on spherical bubble growth break down.

The rejection of particles with different charges and sizes, ranging from a few Ångstroms to tens of nanometers, is key to a wide range of industrial applications, from wastewater treatment to product purification in biotech processes. Carbon nanotubes (CNTs) have long held the promise to revolutionize filtration, with orders of magnitude higher fluxes compared to commercial membranes. CNTs, however, can only reject particles and ions wider than their internal diameter. In this work, the fabrication of aligned boron nitride nanotube (BNNT) membranes capable of rejecting nanoparticles smaller than their internal diameter is reported for the first time. This is due to a mechanism of charge-based rejection in addition to the size-based one, enabled by the BNNTs surface structure and chemistry and elucidated here using high fidelity molecular dynamics and Brownian dynamics simulations. This results in ∼40% higher rejection of the same particles by BNNT membranes than CNT ones with comparable nanotube diameter. Furthermore, since permeance is proportional to the square of the nanotubes' diameter, using BNNT membranes with ∼30% larger nanotube diameter than a CNT membrane with comparable rejection would result in up to 70% higher permeance. These results open the way to the design of more effective nanotube membranes, capable of high particle rejection and, at the same time, high water permeance.

Next-generation processor-chip cooling devices and self-cleaning surfaces can be enhanced by a passive process that requires little to no electrical input, through coalescence-induced nanodroplet jumping. Here, we describe the crucial impact thermal capillary waves and ambient gas rarefaction have on enhancing/limiting the jumping speeds of nanodroplets on low adhesion surfaces. By using high-fidelity non-equilibrium molecular dynamics simulations in conjunction with well-resolved volume-of-fluid continuum calculations, we are able to quantify the different dissipation mechanisms that govern nanodroplet jumping at length scales that are currently difficult to access experimentally. We find that interfacial thermal capillary waves contribute to a large statistical spread of nanodroplet jumping speeds that range from 0-30 m s-1, where the typical jumping speeds of micro/millimeter sized droplets are only up to a few m s-1. As the gas surrounding these liquid droplets is no longer in thermodynamic equilibrium, we also show how the reduced external drag leads to increased jumping speeds. This work demonstrates that, in the viscous-dominated regime, the Ohnesorge number and viscosity ratio between the two phases alone are not sufficient, but that the thermal fluctuation number (Th) and the Knudsen number (Kn) are both needed to recover the relevant molecular physics at nanoscales. Our results and analysis suggest that these dimensionless parameters would be relevant for many other free-surface flow processes and applications that operate at the nanoscale.

Picosecond laser electronic-excitation tagging (PLEET) was demonstrated in a Mach-6 Ludwieg tube at a repetition rate of 100 kHz using a 1064 nm, 100 ps burst-mode laser. The system performance of high-speed velocimetry in unseeded air and nitrogen Mach-6 flows at a static pressure in the range of 5-20 torr were evaluated. Based on time-resolved freestream flow measurements and computational fluid dynamics (CFD) calculations, we concluded that the measurement uncertainty of 100 kHz PLEET measurement for Mach 6 freestream flow condition is ∼1%. The measured velocity profiles with a cone-model agreed well with the CFD computations upstream and downstream of the shockwave; downstream of the shockwave the discrepancy between the CFD and experimental measurement could be attributed to a slight nonzero angle of attack (AoA) or flow unsteadiness. Our results show the potential of utilizing 100 kHz PLEET velocimetry for understanding real-time dynamics of turbulent hypersonic flows and provide the capability of collecting sufficient data across fewer tests in large hypersonic ground test facilities.

Background: Cumulative mortality rate and cumulative mortality risk are two commonly used indicators to measure the impact and severity of diseases. However, they are calculated during a defined life span and assume the subject does not die from other causes. This study aims to use a new indicator, lifetime death probability (LDP), to estimate the lifetime death probabilities for the top five leading causes of death in China and explore the regional differences and trends over time., Methods: LDPs were calculated using a probability additive formula and abridged life tables., Results: In 2014, LDPs for heart disease, cerebrovascular disease, malignancy, respiratory disease, and injury and poisoning were 24.4, 23.7, 19.2, 15.5, and 5.3%, respectively. The LDPs for heart disease and malignancy increased by 7.3 and 0.5%, respectively, compared to those from 2004 to 2005. In contrast, the LDPs for cerebrovascular and respiratory disease decreased by 1.0 and 3.9%, respectively, compared to those in 2004-2005. Across the eastern, central and western regions, malignancy had the highest LDP in the eastern region, cerebrovascular and heart diseases in the central region, and respiratory diseases, and injury and poisoning in the western region., Conclusions: LDP is an effective indicator for comparing health outcomes and can be applied for future disease surveillance. Heart disease and malignancy were the two most common causes of death in China, but with regional differences. There is a need to implement targeted measures to prevent chronic diseases in different regions.

The excess heat factor (EHF) is being adopted nationally for heatwave forecasting in Australia, but there is limited research utilizing it as a predictor for heat-related morbidity from diseases of the urinary system (urinary diseases). In this study, the incidence of eight temperature-prone specific urinary disease categories was analyzed in relation to the EHF. Daily data for maximum and minimum temperature and data for metropolitan hospital emergency department presentations and inpatient admissions for urinary disease were acquired in Adelaide, South Australia, from 1 July 2003 to 31 March 2014. An increased incidence for urolithiasis, acute kidney injury (AKI), chronic kidney disease, and lower urinary tract infections was associated with the EHF. Using the Australian national heatwave definition with the EHF, emergency department presentations increased on heatwave days compared to non-heatwave days for total urinary disease (IRR 1.046, 95% CI 1.016-1.076), urolithiasis (IRR 1.106, 95% 1.046-1.169), and acute kidney injury (AKI) (IRR 1.416, 95% CI 1.258-1.594). Likewise, inpatient admissions increased for total urinary disease (IRR 1.090, 95% CI 1.048-1.133) and AKI (IRR 1.335, 95% CI 1.204-1.480). The EHF is a reliable metric for predicting heat-induced morbidity from urinary disease. Climate change-related elevations in temperature can increase morbidity from urinary disease, especially AKI and urolithiasis. Diseases of the urinary system should be highlighted when providing public health guidance during heatwaves indicated by the EHF.

The classical notion of the coalescence of two droplets of the same radius R is that surface tension drives an initially singular flow. In this Letter we show, using molecular dynamics simulations of coalescing water nanodroplets, that after single or multiple bridges form due to the presence of thermal capillary waves, the bridge growth commences in a thermal regime. Here, the bridges expand linearly in time much faster than the viscous-capillary speed due to collective molecular jumps near the bridge fronts. Transition to the classical hydrodynamic regime only occurs once the bridge radius exceeds a thermal length scale l_{T}∼sqrt[R].

We report the results of molecular dynamics investigations into the behavior of nanoscale water droplets on surfaces subjected to cyclic-frequency normal vibration. Our results show, for the first time, a range of vibration-induced phenomena, including the existence of the following different regimes: evaporation, droplet oscillation, and droplet lift-off. We also describe the effect of different surface wettabilities on evaporation. The outcomes of this work can be utilized in the design of future nanoengineered technologies that employ surface/bulk acoustic waves, such as water-based cooling systems for high-heat-generating processor chips, by tuning the vibration frequency and amplitude, as well as the surface wettability, to obtain the desired performance.

We report nonequilibrium molecular simulations of the vibration-induced heating of nanoscale-thick water layers on a metal substrate. In addition to experimentally confirmed acoustothermal evaporation, we observe hitherto unmapped nucleate and film boiling regimes, accompanied by the generation of unprecedented heat fluxes [∼O(10^{9})  W/m^{2}]. We develop a universal scaling parameter to classify the heat-transfer regimes and to predict the thickness of the residual nonevaporating liquid layer. The results find broad application to systems involving drying, coatings, and sprays.

The properties of water confined inside nanotubes are of considerable scientific and technological interest. We use molecular dynamics to investigate the structure and average orientation of water flowing within a carbon nanotube. We find that water exhibits biaxial paranematic liquid crystal ordering both within the nanotube and close to its ends. This preferred molecular ordering is enhanced when an axial electric field is applied, affecting the water flow rate through the nanotube. A spatially patterned electric field can minimize nanotube entrance effects and significantly increase the flow rate., (© 2015 The Authors.)

The emergence of new applications of molecular dynamics (MD) simulation calls for the development of mass-statting procedures that insert or delete particles on-the-fly. In this paper we present a new mass-stat which we term FADE, because it gradually "fades-in" (inserts) or "fades-out" (deletes) molecules over a short relaxation period within a MD simulation. FADE applies a time-weighted relaxation to the intermolecular pair forces between the inserting/deleting molecule and any neighbouring molecules. The weighting function we propose in this paper is a piece-wise polynomial that can be described entirely by two parameters: the relaxation time scale and the order of the polynomial. FADE inherently conserves overall system momentum independent of the form of the weighting function. We demonstrate various simulations of insertions of atomic argon, polyatomic TIP4P water, polymer strands, and C60 Buckminsterfullerene molecules. We propose FADE parameters and a maximum density variation per insertion-instance that restricts spurious potential energy changes entering the system within desired tolerances. We also demonstrate in this paper that FADE compares very well to an existing insertion algorithm called USHER, in terms of accuracy, insertion rate (in dense fluids), and computational efficiency. The USHER algorithm is applicable to monatomic and water molecules only, but we demonstrate that FADE can be generally applied to various forms and sizes of molecules, such as polymeric molecules of long aspect ratio, and spherical carbon fullerenes with hollow interiors.

Background: The treatment of metastatic colorectal cancer (mCRC) includes drugs targeting the epidermal growth factor receptor (EGFR). Mutation in codon 12 or 13 in the Kirsten rat sarcoma viral oncogene homolog (KRAS) gene, downstream of the EGFR, evokes constitutive activation of the RAS/RAF/MAPK signaling pathway and correlates with resistance to anti-EGFR monoclonal antibody (mAb) therapies. However, a retrospective study reported that a proportion of patients with the KRAS G13D mutation may respond to cetuximab. A similar analysis for panitumumab was not as conclusive. We sought to determine the sensitivity of CRC cell lines to cetuximab or panitumumab treatment and to investigate the correlation of the KRAS mutational status of the CRC cell lines to the responsiveness to cetuximab or panitumumab., Methods: To determine the responsiveness of CRC cell lines to cetuximab or panitumumab, cell lines were treated with an optimized concentration of each mAb, and proliferation assays were conducted., Results: After treatment with cetuximab or panitumumab, at the optimum concentration of 8 μg/well, the KRAS G13D mutant cell lines HCT-116, LoVo, and T84 showed intermediate sensitivity to both treatments, between the resistant KRAS G12V mutant cell line SW480 and the sensitive KRAS wild-type cell line LIM1215. One of the G13D cell lines was significantly more sensitive to panitumumab than to cetuximab (P = .02)., Conclusion: The specific KRAS mutation determines the responsiveness to anti-EGFR monoclonal antibody treatment, corresponding to reported clinical observations.