Anthropogenic forcing has increased the risk of longer-traveling and slower-moving large contiguous heatwaves.

Heatwaves are consecutive hot days with devastating impacts on human health and the environment. These events may evolve across both space and time, characterizing a spatiotemporally contiguous propagation pattern that has not been fully understood. Here, we track the spatiotemporally contiguous heatwaves in both reanalysis datasets and model simulations and examine their moving patterns (i.e., moving distance, speed, and direction) in different continents and periods. Substantial changes in contiguous heatwaves have been identified from 1979 to 2020, with longer persistence, longer traveling distance, and slower propagation. These changes have been amplified since 1997, probably due to the weakening of eddy kinetic energy, zonal wind, and anthropogenic forcing. The results suggest that longer-lived, longer-traveling, and slower-moving contiguous heatwaves will cause more devastating impacts on human health and the environment in the future if greenhouse gas emissions keep rising and no effective measures are taken immediately. Our findings provide important implications for the adaption and mitigation of globally connected extreme heatwaves.

What is the prevalence of orthostatic hypotension in an Australasian emergency department population?

OBJECTIVE: Orthostatic hypotension (OH) is associated with increased morbidity and there is limited research on the prevalence in the Australian ED population. The aim was to determine the prevalence of OH in an Australian ED population. Secondary outcomes included any associations of OH with symptoms, presenting complaints, patient demographics, or hospital admission, and the timing of OH findings. METHODS: Patients presenting to a regional Australasian ED underwent orthostatic measurements at 1, 3 and 5 min of standing following 5 min of supine bed rest. OH was defined as a drop in systolic and/or diastolic blood pressure by ≥20 and ≥10 mmHg, respectively. RESULTS: Of the 312 patients who were enrolled in the study, 69 (22.1%, 95% confidence interval 17.7-27.2%) had OH and 76.8% of cases were detected after 3 min of standing. There was evidence of difference in the prevalence of OH with age (P < 0.001). Similarly, there was evidence of a difference in supine systolic and diastolic blood pressure measurements (P = 0.012 and P < 0.001, respectively) between orthostatic and normotensive subjects. No association was found with OH and hospital admission, presenting complaints or comorbid medical illnesses. CONCLUSIONS: In this single Australian ED population, there was a high prevalence of OH (22.1%) with most cases detected within 3 min of standing. A higher-powered study across multiple sites would better substantiate these findings.

Droperidol versus ondansetron for nausea treatment within the emergency department.

OBJECTIVE: A randomised single-blind trial was undertaken in an adult ED population, comparing the effectiveness of droperidol 2.5 mg IV with ondansetron 8 mg IV for the treatment of nausea and vomiting. METHODS: Patients were randomly allocated to receive droperidol (n = 60) or ondansetron (n = 60). Patients rated their nausea severity on a Visual Analogue Scale (VAS) immediately before and 30 min after drug administration. The primary outcome was of symptom improvement, defined by a VAS change ≥-8 mm 30 min post-treatment. Mean VAS change and percentage experiencing desired effect were secondary outcomes compared. RESULTS: Of 120 study patients, 60 (50%) received droperidol or ondansetron. Symptom improvement occurred in 93% (56 of 60) and 87% (52 of 60), respectively (P = 0.362). Mean VAS change was -38 mm and -29 mm, respectively (P = 0.031). Percentage of patients indicating desired effect was 85% and 63%, respectively (P = 0.006). Additional antiemetics were required for 16% and 37% of subjects, respectively (P = 0.006). CONCLUSION: There was no statistically significant difference in the primary outcome of symptom improvement between droperidol and ondansetron. Secondary outcomes which favour droperidol warrant further exploration.

Catheter-directed thrombolysis for lower limb ischaemia: A retrospective study of treatment outcomes.

INTRODUCTION: Lower limb ischaemia secondary to occlusion of a lower limb artery is a limb-threatening condition that can be effectively treated by catheter-directed thrombolysis (CDT). The purpose of this study was to examine treatment outcomes of CDT both at the time of treatment and ongoing patency up to 12 months following treatment. The secondary aim of the study was to investigate the influence of age of occlusion and treatment duration on success and complication rates. METHOD: A retrospective observational study was performed at a single institution over a 10-year period from 2010 to 2019. Data for patient demographics, vessel occlusion factors and treatment information were obtained and analysed. Patency data were investigated using Kaplan-Meier analyses. RESULTS: A total of 218 limbs in 159 patients were treated during the study period. The aetiology of vessel occlusion was in situ thrombosis or occluded bypass graft in 74.5%. Technical success was achieved in 55.5% with CDT alone and 84.4% by using CDT in combination with adjunctive endovascular procedures (angioplasty or stenting). The overall probability of patency was 0.65 at 3 months and 0.44 at 12 months. The overall rate of major amputation within 30 days of thrombolysis was 8.2%. Thirty-day mortality was 6.3% and was secondary to intracranial haemorrhage in three patients. CONCLUSION: Technical success of CDT was found to be significantly higher when combined with adjunctive endovascular procedures at the time of CDT. Despite an initial moderate technical success, the probability of patency at 12 months was only 44%. The likelihood of bleeding complications and technical and long-term success remain key considerations when selecting patients for CDT.

Inflammatory and oxidative stress responses of healthy elders to solar-assisted large-scale cleaning system (SALSCS) and changes in ambient air pollution: A quasi-interventional study in Xi'an, China.

An outdoor solar assisted large-scale cleaning system (SALSCS) was constructed to mitigate the levels of fine particulate matter (PM2.5) in urban areas of Xi'an China, providing a quasi-experimental opportunity to examine the biologic responses to the changes in pollution level. We conducted this outdoor SALSCS based real-world quasi-interventional study to examine the associations of the SALSCS intervention and changes in air pollution levels with the biomarkers of systemic inflammation and oxidative stress in healthy elders. We measured the levels of 8-hydrox-2-deoxyguanosine (8-OHdG), Interlukin-6 (IL-6), as well as tumor necrosis factor alpha (TNF-α) from urine samples, and IL-6 from saliva samples of 123 healthy retired participants from interventional/control residential areas in two sampling campaigns. We collected daily 24-h PM2.5 samples in two residential areas during the study periods using mini-volume samplers. Data on PM10, gaseous pollutants and weather factors were collected from the nearest national air quality monitoring stations. We used linear mixed-effect models to examine the percent change in each biomarker associated with the SALSCS intervention and air pollution levels, after adjusting for time trend, seasonality, weather factors and personal characteristics. Results showed that the SALSCS intervention was significantly associated with decreases in the geometric mean of biomarkers by 47.6% (95% confidence interval: 16.5-67.2%) for 8-OHdG, 66% (31.0-83.3%) for TNF-α, 41.7% (0.2-65.9%) and 43.4% (13.6-62.9%) for urinary and salivary IL-6, respectively. An inter-quartile range increase of ambient PM2.5 exposure averaged on the day of the collection of bio-samples and the day before (34.1 µg/m3) was associated, albeit non-significantly so, with 22.8%-37.9% increases in the geometric mean of these biomarkers. This study demonstrated that the SALSCS intervention and decreased ambient air pollution exposure results in lower burden of systemic inflammation and oxidative stress in older adults.

Establishing a Platform for Interest and Education in Interventional Radiology Amongst Radiology Trainees.

PURPOSE: Over recent times, procedural Radiologists have begun to establish themselves as the distinct subspecialty of Interventional Radiology (IR). The Interventional Radiology Society of Australasia (IRSA) was established in 1982 to share collaborative ideas, encourage research, and promote education. IRSA developed a weekend registrar workshop attended by Radiology Registrars from Australia and New Zealand. In the 2018 event, we surveyed the Registrars to identify their interest in IR training before and after the workshop. MATERIALS AND METHODS: The event was held over a weekend and consisted of both lectures and hands-on workshops. A survey was handed to all 67 registrants of the workshop and there was a 55% response rate including 78% of females in attendance. RESULTS: Before the workshop, trainees rated their interest in IR training at a mean of 3.7 out of 5. After the workshop, trainees rated their interest in IR training as an average of 4.4 out of 5 (p < 0.001). The difference in interest between males and females before the workshop (4.0 vs. 3.1) was significant (p = 0.003), however after the workshop (4.5 vs. 4.1) was not significant (p = 0.07). The change in interest from attending the workshop was significant between genders, p = 0.03 (male interest increased mean 0.5, female increased mean 1.0). CONCLUSION: We show that a program of lectures and workshops designed to generate interest in IR leads to a significant increase in training interest, particularly amongst females. Other subspecialty groups should consider this type of intervention and promote ongoing education and inspiration. LEVEL OF EVIDENCE: Cross-sectional study, Level IV.

Determinants of personal exposure to fine particulate matter (PM2.5) in adult subjects in Hong Kong.

Personal monitoring for fine particulate matter (PM2.5) was conducted for adults (48 subjects, 18-63years of age) in Hong Kong during the summer and winter of 2014-2015. All filters were analyzed for PM2.5 mass and constituents (including carbonaceous aerosols, water-soluble ions, and elements). We found that season (p=0.02) and occupation (p<0.001) were significant factors affecting the strength of the personal-ambient PM2.5 associations. We applied mixed-effects models to investigate the determinants of personal exposure to PM2.5 mass and constituents, along with within- and between-individual variance components. Ambient PM2.5 was the dominant predictor of (R2=0.12-0.59, p<0.01) and the largest contributor (>37.3%) to personal exposures for PM2.5 mass and most components. For all subjects, a one-unit (2.72µg/m3) increase in ambient PM2.5 was associated with a 0.75µg/m3 (95% CI: 0.59-0.94µg/m3) increase in personal PM2.5 exposure. The adjusted mixed-effects models included information extracted from individual's activity diaries as covariates. The results showed that season, occupation, time indoors at home, in transit, and cleaning were significant determinants for PM2.5 components in personal exposure (R2ß=0.06-0.63, p<0.05), contributing to 3.0-70.4% of the variability. For one-hour extra time spent at home, in transit, and cleaning an average increase of 1.7-3.6% (ammonium, sulfate, nitrate, sulfur), 2.7-12.3% (elemental carbon, ammonium, titanium, iron), and 8.7-19.4% (ammonium, magnesium ions, vanadium) in components of personal PM2.5 were observed, respectively. In this research, the within-individual variance component dominated the total variability for all investigated exposure data except PM2.5 and EC. Results from this study indicate that performing long-term personal monitoring is needed for examining the associations of mass and constituents of personal PM2.5 with health outcomes in epidemiological studies by describing the impacts of individual-specific data on personal exposures.

Nonequilibrium study of the intrinsic free-energy profile across a liquid-vapour interface.

We calculate an atomistically detailed free-energy profile across a heterogeneous system using a nonequilibrium approach. The path-integral formulation of Crooks fluctuation theorem is used in conjunction with the intrinsic sampling method to calculate the free-energy profile for the liquid-vapour interface of the Lennard-Jones fluid. Free-energy barriers are found corresponding to the atomic layering in the liquid phase as well as a barrier associated with the presence of an adsorbed layer as revealed by the intrinsic density profile. Our findings are in agreement with profiles calculated using Widom's potential distribution theorem applied to both the average and the intrinsic profiles as well as the literature values for the excess chemical potential.

Surface thermodynamics of planar, cylindrical, and spherical vapour-liquid interfaces of water.

The test-area (TA) perturbation approach has been gaining popularity as a methodology for the direct computation of the interfacial tension in molecular simulation. Though originally implemented for planar interfaces, the TA approach has also been used to analyze the interfacial properties of curved liquid interfaces. Here, we provide an interpretation of the TA method taking the view that it corresponds to the change in free energy under a transformation of the spatial metric for an affine distortion. By expressing the change in configurational energy of a molecular configuration as a Taylor expansion in the distortion parameter, compact relations are derived for the interfacial tension and its energetic and entropic components for three different geometries: planar, cylindrical, and spherical fluid interfaces. While the tensions of the planar and cylindrical geometries are characterized by first-order changes in the energy, that of the spherical interface depends on second-order contributions. We show that a greater statistical uncertainty is to be expected when calculating the thermodynamic properties of a spherical interface than for the planar and cylindrical cases, and the evaluation of the separate entropic and energetic contributions poses a greater computational challenge than the tension itself. The methodology is employed to determine the vapour-liquid interfacial tension of TIP4P/2005 water at 293 K by molecular dynamics simulation for planar, cylindrical, and spherical geometries. A weak peak in the curvature dependence of the tension is observed in the case of cylindrical threads of condensed liquid at a radius of about 8 Å, below which the tension is found to decrease again. In the case of spherical drops, a marked decrease in the tension from the planar limit is found for radii below ∼ 15 Å; there is no indication of a maximum in the tension with increasing curvature. The vapour-liquid interfacial tension tends towards the planar limit for large system sizes for both the cylindrical and spherical cases. Estimates of the entropic and energetic contributions are also evaluated for the planar and cylindrical geometries and their magnitudes are in line with the expectations of our simple analysis.

Water droplet excess free energy determined by cluster mitosis using guided molecular dynamics.

Atmospheric aerosols play a vital role in affecting climate by influencing the properties and lifetimes of clouds and precipitation. Understanding the underlying microscopic mechanisms involved in the nucleation of aerosol droplets from the vapour phase is therefore of great interest. One key thermodynamic quantity in nucleation is the excess free energy of cluster formation relative to that of the saturated vapour. In our current study, the excess free energy is extracted for clusters of pure water modelled with the TIP4P/2005 intermolecular potential using a method based on nonequilibrium molecular dynamics and the Jarzynski relation. The change in free energy associated with the "mitosis" or division of a cluster of N water molecules into two N/2 sub-clusters is evaluated. This methodology is an extension of the disassembly procedure used recently to calculate the excess free energy of argon clusters [H. Y. Tang and I. J. Ford, Phys. Rev. E 91, 023308 (2015)]. Our findings are compared to the corresponding excess free energies obtained from classical nucleation theory (CNT) as well as internally consistent classical theory (ICCT). The values of the excess free energy that we obtain with the mitosis method are consistent with CNT for large cluster sizes but for the smallest clusters, the results tend towards ICCT; for intermediate sized clusters, we obtain values between the ICCT and CNT predictions. Furthermore, the curvature-dependent surface tension which can be obtained by regarding the clusters as spherical droplets of bulk density is found to be a monotonically increasing function of cluster size for the studied range. The data are compared to other values reported in the literature, agreeing qualitatively with some but disagreeing with the values determined by Joswiak et al. [J. Phys. Chem. Lett. 4, 4267 (2013)] using a biased mitosis approach; an assessment of the differences is the main motivation for our current study.

Prospective randomized comparative evaluation of proximal valve polyurethane and distal valve silicone peripherally inserted central catheters.

PURPOSE: The objective of this study was to evaluate and compare the relative durability and complications between the proximal valve polyurethane and distal valve silicone peripherally inserted central catheters (PICCs). METHODS: Institutional review board approval was obtained. A total of 326 patients (mean age, 50.4 years) was assigned randomly to receive either a proximal valve polyurethane PICC (n = 198) or a distal valve silicone Groshong PICC (n = 194). All PICCs were inserted under radiologic guidance by interventional radiologists. Follow-up data were collected until catheter removal because of complications or treatment completion. RESULTS: The mean catheter dwell time was 25.6 days (range, 1-245 days). Complications were encountered in 26.8% and 47.9% of the proximal valve polyurethane PICCs and distal valve silicone PICCs, respectively (P < .001). Significantly higher incidences of phlebitis (23.2% versus 11.6%, P = .003) and catheter-related infection (6.2% versus 2%, P = 0.043) were noted in the distal valve silicone PICCs. No significant differences in the incidence of catheter occlusion, fracture, or dislodgement were found. Multivariate logistic regression analysis showed a higher complication rate in the distal valve silicone PICCs corrected for patients' age, sex, underlying morbidity, indication, peripheral vein accessed, arm used, catheter tip placement, and the number of venepunctures attempted. CONCLUSIONS: Proximal valve polyurethane PICCs were more durable than distal valve silicone PICCs, which were associated with a higher incidence of phlebitis and infection, probably related to the materials of the catheters and the designs and placements of the catheter valves.

Rupture of aortic pseudoaneursym arising from a transverse aortotomy line 12 years following mechanical aortic valve replacement.

Pseudoaneurysm formation at the site of aortotomy is a rare complication following aortic valve replacement; it appears to be more common in those whose valve is replaced for endocarditis or in those who develop an early postoperative endocarditis or sepsis. We discuss the case of a 77-year-old male, who presented 12 years following mechanical aortic valve replacement, with rupture of an ascending aortic pseudoaneurysm arising from a transverse aortotomy line.

In vivo and in vitro morphometry of the human trachea.

Most morphometric studies of the human trachea have relied on plain radiographs with their attendant limitations. Reports using computed tomography (CT) have focused on the growing trachea or one particular dimension. The aim of this study was to document the morphometry of the adult trachea in vivo using high-resolution chest CT scans, supplemented by data from cadavers. Sixty anonymised high-resolution chest CT scans (aged 22-88 years, 40 males) were analyzed. Scans were performed using a standardized breath-holding technique in patients with no distorting intrathoracic pathology. Standardized tracheal measurements included: length, maximum antero-posterior and transverse diameters, volume, subcarinal angle, and carinal position in relation to the tracheal midline. Measurements were also made in 10 cadaver tracheas (aged 68-101 years, 7 males). CT data showed that mean tracheal length (males 105.1 +/- 9.8 mm, females 98.3 +/- 8.7 mm), maximum antero-posterior and transverse diameters, and tracheal volume (males 35.6 +/- 6.8 cm3, females 24.7 +/- 6.1 cm3) were all significantly greater in men (P < or = 0.01). The subcarinal angle was very variable (mean 78 +/- 20 degrees , range 36-121 degrees ) and showed no correlation with age or gender. The carina was sited to the left of the tracheal midline in 49 (81%) patients. Cadaver tracheas had 14-19 tracheal rings and the posterior membranous trachea was wider in men (17.7 +/- 4.4 mm vs. 11.8 +/- 3.0 mm, P = 0.07). In conclusion, there is marked sexual dimorphism in the morphometry of the human trachea. The variation in adult tracheal dimensions in vivo is greater than in standard descriptions. These data may be valuable when interpreting chest CT scans and when calculating respiratory dead space.