High-'n'-dry? A comparison of cannabis and alcohol use in drivers presenting to hospital after a vehicular collision.

DESIGN: This was a prospective observational study. BACKGROUND AND AIMS: The characteristics of cannabis-involved motor vehicle collisions are poorly understood. This study of injured drivers identifies demographic and collision characteristics associated with high tetrahydrocannabinol (THC) concentrations. SETTING: The study was conducted in 15 Canadian trauma centres between January 2018 and December 2021. CASES: The cases (n = 6956) comprised injured drivers who required blood testing as part of routine trauma care. MEASUREMENTS: We quantified whole blood THC and blood alcohol concentration (BAC) and recorded driver sex, age and postal code, time of crash, crash type and injury severity. We defined three driver groups: high THC (THC ≥ 5 ng/ml and BAC = 0), high alcohol (BAC ≥ 0.08% and THC = 0) and THC/BAC-negative (THC = 0 = BAC). We used logistic regression techniques to identify factors associated with group membership. FINDINGS: Most injured drivers (70.2%) were THC/BAC-negative; 1274 (18.3%) had THC > 0, including 186 (2.7%) in the high THC group; 1161 (16.7%) had BAC > 0, including 606 (8.7%) in the high BAC group. Males and drivers aged less than 45 years had higher adjusted odds of being in the high THC group (versus the THC/BAC-negative group). Importantly, 4.6% of drivers aged less than 19 years had THC ≥ 5 ng/ml, and drivers aged less than 19 years had higher unadjusted odds of being in the high THC group than drivers aged 45-54 years. Males, drivers aged 19-44 years, rural drivers, seriously injured drivers and drivers injured in single-vehicle, night-time or weekend collisions had higher adjusted odds ratios (aORs) for being in the high alcohol group (versus THC/BAC-negative). Drivers aged less than 35 or more than 65 years and drivers involved in multi-vehicle, daytime or weekday collisions had higher adjusted odds for being in the high THC group (versus the high BAC group). CONCLUSIONS: In Canada, risk factors for cannabis-related motor vehicle collisions appear to differ from those for alcohol-related motor vehicle collisions. The collision factors associated with alcohol (single-vehicle, night-time, weekend, rural, serious injury) are not associated with cannabis-related collisions. Demographic factors (young drivers, male drivers) are associated with both alcohol and cannabis-related collisions, but are more strongly associated with cannabis-related collisions.

Effect of surface gallium termination on the formation and emission energy of an InGaAs wetting layer during the growth of InGaAs quantum dots by droplet epitaxy.

Self-assembled quantum dots (QDs) based on III-V semiconductors have excellent properties for applications in quantum optics. However, the presence of a 2D wetting layer (WL) which forms during the Stranski-Krastanov growth of QDs can limit their performance. Here, we investigate WL formation during QD growth by the droplet epitaxy technique. We use a combination of photoluminescence excitation spectroscopy, lifetime measurements, and transmission electron microscopy to identify the presence of an InGaAs WL in these droplet epitaxy QDs, even in the absence of distinguishable WL luminescence. We observe that increasing the amount of Ga deposited on a GaAs (100) surface prior to the growth of InGaAs QDs leads to a significant reduction in the emission wavelength of the WL to the point where it can no longer be distinguished from the GaAs acceptor peak emission in photoluminescence measurements. However increasing the amount of Ga deposited does not suppress the formation of a WL under the growth conditions used here.

Does point-of-care ultrasonography improve diagnostic accuracy in emergency department patients with undifferentiated hypotension? An international randomized controlled trial from the SHOC-ED investigators.

PURPOSE: Point-of-care ultrasonography (POCUS) is an established tool in the management of hypotensive patients in the emergency department (ED). We compared the diagnostic accuracy of a POCUS protocol versus standard assessment without POCUS in patients with undifferentiated hypotension. METHODS: This was an international, multicenter randomized controlled trial included three EDs in North America and three in South Africa from September 2012 to December 2016. Hypotensive patients were randomized to early POCUS protocol plus standard care (POCUS group) or standard care without POCUS (control group). Initial and secondary diagnoses were recorded at 0 and 60 min. The main outcome was measures of diagnostic accuracy of a POCUS protocol in differentiating between cardiogenic and non-cardiogenic shock. Secondary outcomes were diagnostic performance for shock sub-types, as well as changes in perceived category of shock and overall diagnosis. RESULTS: Follow-up was completed for 270 of 273 patients. For cardiogenic shock, the POCUS-based diagnostic approach (POCUS) performed similarly to the non-POCUS approach (control) for specificity [95.5% (89.9-98.5) vs.93.8% (87.7-97.5)]; positive likelihood ratio (17.92 vs 14.80); negative likelihood ratio (0.21 vs 0.09) and diagnostic odds ratio (85.6 vs 166.57), with a similar overall diagnostic accuracy between the two approaches [93.7% (88-97.2) vs 93.6% (87.8-97.2)]. Diagnostic performance measures were similar across sub-categories of shock. CONCLUSION: This is the first randomized controlled trial to compare diagnostic performance of a POCUS protocol to standard care without POCUS in undifferentiated hypotensive ED patients. POCUS performed well diagnostically in undifferentiated hypotensive patients, especially as a rule-in test; however, performance did not differ meaningfully from standard assessment.

RéSUMé: OBJECTIF: L'échographie au point d'intervention (POCUS) est un outil bien établi dans la gestion des patients hypotendus dans le service des urgences. Nous avons comparé la précision diagnostique d'un protocole POCUS par rapport à une évaluation standard sans POCUS chez des patients présentant une hypotension indifférenciée. MéTHODES: Il s'agissait d'un essai contrôlé randomisé international multicentrique incluant 3 services d'urgence en Amérique du Nord et 3 en Afrique du Sud de septembre 2012 à décembre 2016. Les patients hypotenseurs ont été répartis par randomisation selon le protocole POCUS précoce plus les soins standard (groupe POCUS) ou les soins standard sans POCUS (groupe témoin). Les diagnostics initiaux et secondaires ont été enregistrés à 0 et 60 minutes. Le principal résultat était la mesure de la précision diagnostique d'un protocole POCUS pour différencier le choc cardiogénique du choc non cardiogénique. Les résultats secondaires étaient la performance diagnostique pour les sous-types de chocs, ainsi que les changements dans la perception de la catégorie de choc et du diagnostic global. RéSULTATS: Le suivi a été complété pour 270 des 273 patients. Pour le choc cardiogénique, l'approche diagnostique basée sur le POCUS (POCUS) a donné des résultats similaires à l'approche non-POCUS (Contrôle) pour la spécificité (95,5 % (89,9­98,5) vs 93,8 % (87,7­97,5)) ; Rapport de vraisemblance positif (17,92 vs 14,80) ; Le rapport de vraisemblance négatif (0,21 vs 0,09) et le rapport de cotes diagnostiques (85,6 vs 166,57), avec une précision diagnostique globale similaire entre les deux approches (93,7 % (88­97,2) vs 93,6 % (87,8­97,2). Les mesures de performance diagnostique étaient similaires dans toutes les sous-catégories de choc. CONCLUSION: Il s'agit du premier essai contrôlé randomisé visant à comparer la performance diagnostique d'un protocole POCUS aux soins standard sans POCUS chez des patients hypotendus indifférenciés aux urgences. La POCUS a donné de bons résultats diagnostiques chez les patients hypotendus indifférenciés, surtout en tant que test de référence ; cependant, les performances ne diffèrent pas de manière significative de l'évaluation standard.

Understanding the policy dynamics of COVID-19 in the UK: Early findings from interviews with policy makers and health care professionals.

The UK government response to COVID-19 has been heavily criticised. We report witnesses' perceptions of what has shaped UK policies and how these policies have been received by healthcare workers. Such studies are usually affected by hindsight. Here we deploy a novel prospective approach to capture real-time information. We are historians, social scientists and biomedical researchers who study how societies cope with infectious disease. In February 2020 we began regular semi-structured calls with prominent members of policy communities, and health care professionals, to elicit their roles in, and reactions to, the pandemic response. We report witnesses' perceptions that personal protective equipment (PPE) stocks were too small, early warnings have not led to sufficiently rapid policy decisions, and a lack of transparency is sapping public trust. Significant successes include research mobilisation. The early experiences and reactions of our witnesses suggest important issues for investigation, notably a perception of delay in decision making.

Density-Driven Flows in Evaporating Binary Liquid Droplets.

In the evaporation of microlitre liquid droplets, the accepted view is that surface tension dominates and the effect of gravity is negligible. We report, through the first use of rotating optical coherence tomography, that a change in the flow pattern and speed occurs when evaporating binary liquid droplets are tilted, conclusively showing that gravitational effects dominate the flow. We use gas chromatography to show that these flows are solutal in nature, and we establish a flow phase diagram demonstrating the conditions under which different flow mechanisms occur.

Magnetic Levitation Stabilized by Streaming Fluid Flows.

We demonstrate that the ubiquitous laboratory magnetic stirrer provides a simple passive method of magnetic levitation, in which the so-called "flea" levitates indefinitely. We study the onset of levitation and quantify the flea's motion (a combination of vertical oscillation, spinning and "waggling"), finding excellent agreement with a mechanical analytical model. The waggling motion drives recirculating flow, producing a centripetal reaction force that stabilized the flea. Our findings have implications for the locomotion of artificial swimmers and the development of bidirectional microfluidic pumps, and they provide an alternative to sophisticated commercial levitators.

A sliding hip screw augmented with 2 screws is biomechanically similar to an inverted triad of cannulated screws in repair of a Pauwels type-III fracture.

OBJECTIVE: Pauwels III femoral neck fractures are highly unstable. These fractures are commonly treated with three cannulated screws or sliding hip screw (SHS) implants, however high rates of non-union persist. A hybrid SHS construct has recently been proposed. The objective of the study was to compare this construct to the familiar inverted triad of cannulated screws and to a single SHS. METHODS: Fourth generation biomechanical femur analogs were used to create a highly repeatable injury model. The hybrid SHS construct contained a SHS with two superior cannulated screws in an inverted triangle configuration. Eight samples for each construct were biomechanically evaluated and the results compared using ANOVA (p<0.05). RESULTS: The cannulated triad and hybrid SHS provided similar stiffness and fracture gap motion. The single SHS exhibited significantly lower stiffness and larger fracture plane diastasis than either the inverted triangle of cannulated screws or hybrid SHS (p<0.05). None of the constructs exhibited catastrophic failure during cyclic loading nor under loading up to 2.5 times body weight. CONCLUSIONS: The single SHS provided the least stable fracture fixation, while the inverted triad and hybrid SHS constructs were mechanically similar. The fracture repair simulated here illustrates how these repairs have the potential to return near pre-fracture strength in ideal conditions with young, healthy bone. However; in clinical situations where comminution impairs load transfer through the cortices the hybrid SHS may be the most favorable option.

Changes in behaviour drive inter-annual variability in the at-sea distribution of northern gannets.

The at-sea distribution of seabirds primarily depends on the distance from their breeding colony, and the abundance, distribution and predictability of their prey, which are subject to strong spatial and temporal variation. Many seabirds have developed flexible foraging strategies to deal with this variation, such as increasing their foraging effort or switching to more predictable, less energy dense, prey, in poor conditions. These responses may vary both within and between individuals, and understanding this variability is vital to predict the population-level impacts of spatially explicit environmental disturbances, such as offshore windfarms. We conducted a multi-year tracking study in order to investigate the inter-annual variation in the foraging behaviour and location of a population of northern gannets breeding on Alderney in the English Channel. To do so, we investigated the link between individual-level behaviour and population-level behaviour. We found that a sample of gannets tracked in 2015 had longer trip durations, travelled further from the colony and had larger core foraging areas and home range areas than gannets tracked in previous years. This inter-annual variation may be associated with oceanographic conditions indexed by the North Atlantic Oscillation (NAO). Our findings suggest that this inter-annual variation was driven by individuals visiting larger areas in all of their trips rather than individuals diversifying to visit more, distinct areas. These findings suggest that, for gannets at least, if prey becomes less abundant or more widely distributed, more individuals may be required to forage further from the colony, thus increasing their likelihood of encountering pressures from spatially explicit anthropogenic disturbances.

Fine resolution mapping of population age-structures for health and development applications.

The age-group composition of populations varies considerably across the world, and obtaining accurate, spatially detailed estimates of numbers of children under 5 years is important in designing vaccination strategies, educational planning or maternal healthcare delivery. Traditionally, such estimates are derived from population censuses, but these can often be unreliable, outdated and of coarse resolution for resource-poor settings. Focusing on Nigeria, we use nationally representative household surveys and their cluster locations to predict the proportion of the under-five population in 1 × 1 km using a Bayesian hierarchical spatio-temporal model. Results showed that land cover, travel time to major settlements, night-time lights and vegetation index were good predictors and that accounting for fine-scale variation, rather than assuming a uniform proportion of under 5 year olds can result in significant differences in health metrics. The largest gaps in estimated bednet and vaccination coverage were in Kano, Katsina and Jigawa. Geolocated household surveys are a valuable resource for providing detailed, contemporary and regularly updated population age-structure data in the absence of recent census data. By combining these with covariate layers, age-structure maps of unprecedented detail can be produced to guide the targeting of interventions in resource-poor settings.

Burnout in emergency department healthcare professionals is associated with coping style: a cross-sectional survey.

INTRODUCTION: Ineffective coping may lead to impaired job performance and burnout, with adverse consequences to staff well-being and patient outcomes. We examined the relationship between coping styles and burnout in emergency physicians, nurses and support staff at seven small, medium and large emergency departments (ED) in a Canadian health region (population 500,000). METHODS: Linear regression with the Coping Inventory for Stressful Situations (CISS) and Maslach Burnout Inventory (MBI) was used to evaluate the effect of coping style on levels of burnout in a cross-sectional survey of 616 ED staff members. CISS measures coping style in three categories: task-oriented, emotion-oriented and avoidance-oriented coping; MBI, in use for 30 years, assesses the level of burnout in healthcare workers. RESULTS: Task-oriented coping was associated with decreased risk of burnout, while emotion-oriented coping was associated with increased risk of burnout. DISCUSSION: Specific coping styles are associated with varied risk of burnout in ED staff across several different types of hospitals in a regional network. Coping style intervention may reduce burnout, while leading to improvement in staff well-being and patient outcomes. Further studies should focus on building and sustaining task-oriented coping, along with alternatives to emotion-oriented coping.

Comparison of the pregnancy rates and costs per calf born after fixed-time artificial insemination or artificial insemination after estrus detection in Bos indicus heifers.

This study compared pregnancy rates (PRs) and costs per calf born after fixed-time artificial insemination (FTAI) or AI after estrus detection (i.e., estrus detection and AI, EDAI), before and after a single PGF2α treatment in Bos indicus (Brahman-cross) heifers. On Day 0, the body weight, body condition score, and presence of a CL (46% of heifers) were determined. The heifers were then alternately allocated to one of two FTAI groups (FTAI-1, n = 139) and (FTAI-2, n = 141) and an EDAI group (n = 273). Heifers in the FTAI groups received an intravaginal progesterone-releasing device (IPRD; 0.78 g of progesterone) and 1 mg of estradiol benzoate intramuscularly (im) on Day 0. Eight days later, the IPRD was removed and heifers received 500 µg of PGF2α and 300 IU of eCG im; 24 hours later, they received 1 mg estradiol benzoate im and were submitted to FTAI 30 to 34 hours later (54 and 58 hours after IPRD removal). Heifers in the FTAI-2 group started treatment 8 days after those in the FTAI-1 group. Heifers in the EDAI group were inseminated approximately 12 hours after the detection of estrus between Days 4 and 9 at which time the heifers that had not been detected in estrus received 500 µg of PGF2α im and EDAI continued until Day 13. Heifers in the FTAI groups had a higher overall PR (proportion pregnant as per the entire group) than the EDAI group (34.6% vs. 23.2%; P = 0.003), however, conception rate (PR of heifers submitted for AI) tended to favor the estrus detection group (34.6% vs. 44.1%; P = 0.059). The cost per AI calf born was estimated to be $267.67 and $291.37 for the FTAI and EDAI groups, respectively. It was concluded that in Brahman heifers typical of those annually mated in northern Australia FTAI compared with EDAI increases the number of heifers pregnant and reduces the cost per calf born.

A method to modify angle-stable intramedullary nail construct compliance.

Traditional interlocked intramedullary (IM) nails have recently been modified to provide enhanced angular stability. These so-called 'angle-stable' IM nails are designed to eliminate construct toggle and also provide increased axial, bending, and torsional stiffness. While this added stability is needed for small fracture gaps to heal, angle-stable nails may be too stiff for large fracture gaps to unite. Even though relative stability is recommended for large fracture gaps, recent in vivo data indicates that traditional nails may allow for too much motion for healing to occur. The current study evaluated a modified technique for implanting an angle-stable nail which allows for an intermediate amount of stability. The compliance of the nail construct was adjusted by over-drilling the near cortex interlocking hole. This led to increased construct motion in torsion, but less so in axial compression and bending. This modification creates stability which is partway between angle-stable and traditional IM nail designs. These findings were unchanged after 50,000 fatigue loading cycles. By carefully selecting the magnitude of over-drilling, the compliance of the construct can easily be modified as it is being implanted. This design modification may lead to more reliable fracture union since the surgeon can tailor the nail compliance to the injury and bone quality.

Biomechanical performance of variable and fixed angle locked volar plates for the dorsally comminuted distal radius.

BACKGROUND: The ideal treatment strategy for the dorsally comminuted distal radius fracture continues to evolve. Newer plate designs allow for variable axis screw placement while maintaining the advantages of locked technology. The purpose of this study is to compare the biomechanical properties of one variable axis plate with two traditional locked constructs. METHODS: Simulated fractures were created via a distal 1 cm dorsal wedge osteotomy in radius bone analogs. The analogs were of low stiffness and rigidity to create a worst-case strength condition for the subject radius plates. This fracture-gap model was fixated using one of three different locked volar distal radius plates: a variable axis plate (Stryker VariAx) or fixed axis (DePuy DVR, Smith & Nephew Peri-Loc) designs. The constructs were then tested at physiologic loading levels in axial compression and bending (dorsal and volar) modes. Construct stiffness was assessed by fracture gap motion during the different loading conditions. As a within-study control, intact bone analogs were similarly tested. RESULTS: All plated constructs were significantly less stiff than the intact control bone models in all loading modes (p<0.040). Amongst the plated constructs, the VariAx was stiffest axially (p=0.032) and the Peri-Loc was stiffest in bending (p<0.024). CONCLUSION: In this analog bone fracture gap model, the variable axis locking technology was stiffer in axial compression than other plates, though less stiff in bending.

Ovarian dynamics in response to two modified intravaginal progesterone releasing device and oestradiol benzoate based ovulation synchronisation protocols designed for use in Brahman heifers.

The objective was to investigate the ovarian response of Brahman heifers to two modified ovulation synchronisation protocols developed to increase the proportion of normal synchronous ovulations. Experiment 1 characterised the growth of the ovulatory follicle in heifers (n=19) treated with an intravaginal progesterone releasing device (IPRD) and oestradiol benzoate (ODB), to determine the optimal time to induce ovulation. Using the findings from Experiment 1, Experiment 2 investigated the effect of reducing the duration of IPRD insertion and increasing the interval from IPRD removal to ODB treatment (modified protocol 1 - OPO-6; n=20), and omitting ODB treatment at the time of IPRD insertion (modified protocol 2 - PO-6; n=20). An IPRD (0.78 g progesterone) was inserted at Day 0 (OPO-8) or Day 2 (OPO-6 and PO-6) and all heifers also received 1 mg ODB i.m. Day 8: IPRD removed + 500 µg cloprostenol i.m. At 24 h (OPO-8) and 36 h (OPO-6 and PO-6) post IPRD removal: 1 mg ODB i.m. Fixed-time AI (FTAI) occurred at 54 h for OPO-8 and 72 h for OPO-6 and PO-6, post IPRD removal. After IPRD treatment all OPO-6 and OPO-8 heifers initiated a new follicular wave whereas 25% of PO-6 heifers failed. Diameter of the dominant follicle was larger at FTAI in the PO-6 (11.34 ± 0.50 mm) compared to the OPO-8 protocol (9.74 ± 0.51 mm; P<0.05), but similar to the OPO-6 protocol (10.52 ± 0.51 mm). Proportion of ovulations occurring 12 h prior and 24 h post FTAI was similar for the PO-6 (80%) and OPO-6 (75%) protocols but numerically lower in the OPO-8 heifers (60%). The apparent improvement in ovarian response in heifers treated with the modified protocols needs to be confirmed in larger field studies.

Triggered indistinguishable single photons with narrow line widths from site-controlled quantum dots.

In this Letter, we present narrow line width (7 µeV), nearly background-free single-photon emission (g((2))(0) = 0.02) and highly indistinguishable photons (V = 0.73) from site-controlled In(Ga)As/GaAs quantum dots. These excellent properties have been achieved by combining overgrowth on ex situ pit-patterned substrates with vertical stacking of spectrally distinct quantum dot layers. Our study paves the way for large-scale integration of quantum dots into quantum photonic circuits as indistinguishable single-photon sources.

Universal recovery of the energy-level degeneracy of bright excitons in InGaAs quantum dots without a structure symmetry.

The lack of structural symmetry which usually characterizes semiconductor quantum dots lifts the energetic degeneracy of the bright excitonic states and hampers severely their use as high-fidelity sources of entangled photons. We demonstrate experimentally and theoretically that it is always possible to restore the excitonic degeneracy by the simultaneous application of large strain and electric fields. This is achieved by using one external perturbation to align the polarization of the exciton emission along the axis of the second perturbation, which then erases completely the energy splitting of the states. This result, which holds for any quantum dot structure, highlights the potential of combining complementary external fields to create artificial atoms meeting the stringent requirements posed by scalable semiconductor-based quantum technology.

Fabrication of a self-aligned cross-wire quantum-dot chain light emitting diode by molecular beam epitaxial regrowth.

The fabrication of a cross-wire p-i-n light emitting diode (LED) by molecular beam epitaxial overgrowth on mesa-patterned GaAs(100) substrates is presented. Micron-wide mesa stripes fabricated by standard photolithography are subsequently narrowed to sub-micron dimensions by GaAs overgrowth due to net migration towards the mesa top. Chains of InAs quantum dots (QDs) can then be grown in a self-aligned manner on top of the narrow GaAs ridge mesa, forming the active region of the QD-chain LED. The kinetics of the overgrowth is discussed and the electroluminescence operation of the LED is presented.