Search

Ultrasound-guided peripheral intravenous cannulation (USGPIVC) benefits patients with difficult intravenous access (DIVA) through visualising otherwise non-visible and non-palpable veins. Supervised live-case training is an important component of learning this skill, but supervisor availability can present a barrier limiting or delaying staff completing their training.The aim of this study was to determine the first-attempt success rate of newly trained USGPIVC inserters using remote supervision and timely written feedback based on app-based screen recordings taken during insertion. Secondary aims were overall procedural success, and inserter and patient experiences.This study is an observational cohort study carried out between October and December 2021. Fourteen newly trained junior medical officers (JMOs) were eligible to utilise USGPIVC on a minimum of five consenting patients while simultaneously recording the ultrasound screen during insertion to capture their technique. Feedback was generated following expert review of these recordings against a standardised feedback tool.Average first-attempt success was 71% (n = 72) in the 102 patients recruited. The average time for JMOs to receive feedback was 30 h, and 13 JMOs (93%) felt well supported and completed the remote training pathway. The majority of patients were female (n = 59; 58%), were aged 41-80 years (n = 75; 74%) and had ≥2 risk factors for DIVA (n = 57; 56%).First-attempt success rates were similar when comparing remote supervision used in this study to direct supervision used by other studies.This finding supports incorporating remote supervision into training guidelines for USGPIVC as an alternative method of supervision, particularly when supervisor availability is limited.

An increasing number of zero emission powertrain technologies will be required for meeting future CO2 targets. While this demand will be met by battery and fuel cell electric vehicles in several markets, other solutions are needed for harder to electrify sectors. Hydrogen (H2) internal combustion engines (ICEs) have become an attractive option for high power, high duty cycle vehicles and are expected to play a strong role in achieving zero emission goals. A unique characteristic of H2 ICEs is their ability to operate extremely lean, with lambda (λ) greater than 2. At such conditions, a multitude of benefits are observed including higher thermal efficiency, lower engine-out nitrogen oxides (NOx) emissions, and mitigating common problems with H2 abnormal combustion such pre-ignition and knock. However, two critical issues arise during extreme enleanment of H2 ICEs which have practical implications on controls and calibration of these engines. The first is the ability to properly measure air fuel ratio (AFR); both in a test cell environment and on-vehicle. The second is the deteriorating combustion efficiency with enleanment despite relative engine stability. In this study, several sources of error when measuring AFR for H2 ICEs are discussed and quantified. A H2-specific AFR equation is derived and the sensitivity to various measured combustion products is explored. It is shown that among these, H2 fuel slip introduces the highest sensitivity to exhaust-measured AFR. The challenge this H2 slip AFR sensitivity poses for closed-loop transient controls is explored and the impact on NOx emissions is highlighted.

In this study, the effect of elevated fuel temperatures on the spray characteristics of gasoline-ethanol blends were studied in an optically accessible constant volume spray and combustion vessel. MAHLE SmartHeat® is a fuel heater located directly upstream of the fuel injector. High speed images of the spray injected from a six-hole gasoline direct injection injector typical of a side-injection engine were captured with shadowgraph imaging technique. Two fuel blends, gasoline with 10% ethanol (E10) and 85% ethanol (E85) were investigated at ambient conditions of 1 bar, 45°C and 4 bar, 180°C respectively at an injection pressure of 100 bar. Fuel temperatures were varied from 75 to 250°C. A comparison of the near nozzle and the global spray characteristics was made for the two fuels at those temperatures. Results showed that flash boiling leads to two primary effects for the two fuel blends: (i) an appreciable increase in spray angle near the exit of the nozzle followed by (ii) a decrease in spray angle downstream of the nozzle due to the interaction of the plumes and the collapsing of the spray. Furthermore, for both fuel blends, upon flash boiling, entrainment and mixing were reduced downstream of the nozzle because of the collapse of the spray. To reduce this effect, nozzle orientations and geometries should be modified.

Focused cardiac ultrasound (FCU) training in critical care is restricted by availability of instructors. Supervised training may be substituted by self-directed learning with an ultrasound simulator guided by automated electronic learning, enabling scalability.We prospectively compared learning outcomes in novice critical care physicians after completion of a supervised one-and-a-half-day workshop model with a self-guided course utilizing a simulator over four weeks. Both groups had identical pre-workshop on-line learning (20h). Image quality scores were compared using FCU performed on humans without pathology. Interpretive knowledge was compared using 20MCQ tests.Of 161 eligible, 145 participants consented. Total Image quality scores were higher in the Simulator group (95.2% vs. 66.0%, P .001) and also higher for each view (all P .001). Interpretive knowledge was not different before (78.6% vs. 79.0%) and after practical training (74.7% vs. 76.1%) and at 3 months (81.0% vs. 77.0%, all P .1). Including purchase of the simulator and ultrasound equipment, the simulator course required lower direct costs (AUD$796 vs. $1724 per participant) and instructor time (0.5 vs.1.5 days) but similar participant time (2.8 vs. 3.0 days).Self-directed learning with ultrasound simulators may be a scalable alternative to conventional supervised teaching with human models.

With a trend towards a zero-carbon dioxide (CO2) tailpipe future, driven by legislation and societal factors, engine manufacturers globally are investigating the use of alternative fuels that can minimize or eliminate tailpipe CO2. Hydrogen (H2) has re-emerged as a viable alternative fuel for combustion engines, aided by its relative flexibility to operating condition resulting from a wide flammability range, and the diversity of H2 production sources. An increasing share of H2 production is accomplished through the use of renewable energy, providing improved well-to-tank / cradle to grave and total life-cycle CO2 budgets. H2 as a combustion fuel is exceptionally prone to abnormal combustion, e.g.

In an effort to reduce fuel consumption and lower emissions output, there is a growing need for high efficiency engines in power generation. Ultra-lean (λ > ∼1.6) combustion via air dilution is an enabling technology for achieving high efficiencies while simultaneously reducing emissions of nitrogen oxides (NOx). Jet ignition is a pre-chamber-based combustion system that enables ultra-lean operation beyond what is achievable with traditional spark ignition engines. In this paper, results and analyses related to the downspeeding of a 390cc, high efficiency low-output single cylinder jet ignition engine operating ultra-lean are presented. The engine was developed as part of the US Department of Energy’s Advanced Research Projects Agency–Energy (DOE ARPA-E) GENSETS program1. The purpose of the program is to develop technologies for use in high efficiency combined heat and power generator sets. Due to the intended application of power generation, optimization of the engine for a specific operating condition is critical. An efficiency loss breakdown based on the Thermodynamic First Law is used to analyze the interdependent trends of engine speed, brake power, and normalized air-fuel ratio, lambda, with the aim of optimizing these parameters for brake thermal efficiency. The general trends of efficiency loss pathways with enleanment are found to be relatively insensitive to speed and load although the magnitude of the loss pathways changes. As the relative importance of the efficiency loss pathways changes with operating condition, so too does the lambda at which peak brake thermal efficiency occurs. The “peak efficiency lambda” was found to be at its leanest at low speed and high power where the influence of heat transfer is greatest and mechanical losses are minimized.

Neutrophils and dendritic cells (DC) converge at sites of acute inflammation in the skin following pathogen deposition by the bites of arthropod vectors or by needle injection. How neutrophils might interact with and modulate the function of DCs in these inflammatory settings has not been previously addressed. Neutrophils are the predominant recruited and infected cells during the earliest stage of Leishmania major infection in the skin. The infected neutrophils recovered from the skin expressed elevated levels of apoptotic markers and were preferentially captured by dermal DCs, the majority of which acquired their parasites via uptake of infected neutrophils. Neutrophil depletion augmented the expression of activation markers on infected DCs and their ability to present Leishmania antigen ex vivo, and markedly enhanced CD4+ T cell priming against parasite-derived antigen in vivo. The findings suggest that L. major exploits the apoptotic cell clearance function of DCs to suppress the development of acquired resistance until the acute neutrophilic response is resolved.

As leishmanioses são um espectro de doenças causadas por parasitas do gênero Leishmania. Por ser um patógeno intracelular obrigatório, infectando principalmente macrófagos e neutrófilos, a produção de radicais de oxigênio e nitrogênio poderia ser importante fator na eliminação de parasitas. No caso específico da infecção causada por Leishmania amazonensis, uma importante espécie causadora de leishmaniose cutânea no Brasil, não há dados na literatura demonstrando o efeito desses radicais em infecções in vivo. Dados do nosso grupo confirmaram que o óxido nítrico possui um importante papel na eliminação dos parasitas em infecções causadas por L. amazonensis in vivo, porém o ânion superóxido e o peróxido de hidrogênio não parecem estar associados com a morte dos parasitas in vivo. Neste trabalho, nós mostramos que animais C57BL/6 deficientes da subunidade gp91phox da NADPH oxidase de fagócitos (gp91phox-/-) infectados de forma subcutânea com L. amazonensis desenvolvem lesões maiores nas primeiras semanas de infeção e lesões menores na fase crônica da doença quando comparados a animais selvagens (WT). Entretanto, ambos camundongos WT e gp91phox-/- apresentaram a mesma carga parasitária. Nós detectamos altos níveis de IL-17 nos linfonodos drenantes 8 semanas pós infecção (p.i.) e baixos níveis de mRNA de IL-1 no sítio da lesão 12 e 16 semanas p.i. nos camundongos gp91phox-/-. Há dados controversos na literatura sobre o papel dos neutrófilos nas infecções causadas por Leishmania principalmente quando diferentes rotas de inoculação são usadas. Considerando a relevância dessas células para produção de ROS e prevendo alterações importantes do efeito de ROS quando a rota de inoculação é alterada, nós comparamos a resposta imune inata gerada nas rotas de inoculação mais usadas no estudo da leishmaniose, as rotas subcutânea e intradérmica. Porém, usamos o modelo de infecção por L. major por este ser mais bem estabelecido na literatura. Duas horas p.i., a infecção intradérmica com L. major apresentou massivo recrutamento de neutrófilos e maiores níveis de expressão de mRNA de CXCL-1, seguido por um intenso recrutamento de monócitos inflamatórios Ly6Chi 48h e 9 dias p.i. quando comparados à infecção subcutânea. Este mais intenso perfil inflamatório observado no sítio intradérmico infectado também foi acompanhado por uma mais eficiente captura dos parasitas. Nós observamos um aumento de 10 vezes no número de células infectadas neste sítio nos tempos observados. Por outro lado, células dendríticas e macrófagos representaram a maioria das células infectadas no sítio subcutâneo. Devido à essa confirmada e importante participação de neutrófilos na infecção intradérmica, utilizamos essa rota de inoculação para determinar a influência de ROS em nosso modelo de infecção por L. amazonensis. Quando infectados de forma intradérmica com formas metacíclicas de L. amazonensis, os camundongos gp91phox-/- apresentaram lesões maiores desde 4 semanas p.i. com grande inflamação, densas áreas necróticas e perda de tecido, porém sem apresentar diferenças na carga parasitária. Curiosamente, os níveis de citocinas inflamatórias não se alteraram durante o curso de infeção, porém nós detectamos uma extensa acumulação de neutrófilos no sítio intradérmico de infecção. O elevado número de neutrófilos em camundongos gp91phox-/- foi associado com alta frequência e números de neutrófilos necróticos em 8 semanas p.i. e isso pode ser o fator principal responsável pelo fenótipo inflamatório observado nestes camundongos. Estes experimentos sugerem que radicais de oxigênio têm um importante papel desde estágios iniciais da infecção causada por L. amazonensis, controlando o fluxo de neutrófilos para o sítio da lesão, impedindo a necrose inflamatória nestas células e consequentemente a inflamação dos tecidos infectados. Além disso, a rota de inoculação influencia profundamente o efeito das espécies reativas de oxigênio (ROS) na infecção por L. amazonensis, visto que as principais células produtoras de ROS, os neutrófilos, demonstram um papel proeminente somente na infecção intradérmica. Este é o primeiro trabalho a mostrar o efeito do ROS em Leishmania em um modelo aproximado em relação à infecção natural, indicando uma via mais fisiológica para o estudo de ROS em infecções causadas por Leishmania. Leishmaniasis are a wide spectrum of diseases caused by parasites of the genus Leishmania. Because these are obligatory intracellular pathogens, infecting mainly macrophages and neutrophils, oxygen and nitrogen radicals production could be important factors in parasite killing. In the specific case of infection caused by Leishmania amazonensis, an important species causing cutaneous leishmaniasis in Brazil, there is no data in the literature demonstrating the effect of these radicals on the infection in vivo. Data from our group confirmed that nitric oxide has an important role in parasite killing in L. amazonensis infection, but superoxide and hydrogen peroxide do not appear to be associated with parasite killing in vivo. In this work, we showed that C57BL/6 mice deficient in the gp91phox subunit of NADPH-dependent oxidase of phagocytes (gp91phox-/-) infected subcutaneously with L. amazonensis develop larger lesions in the first weeks of infection and smaller lesions in the chronic phase of the disease when compared to wild type animals (WT). However, both WT and gp91phox-/- mice presented similar parasite loads. We detected higher levels of IL-17 in draining lymph nodes 8 weeks post infection (p.i.) and lower mRNA levels of IL-1 in the lesion site 12 and 16 weeks p.i. in gp91phox-/- mice. There are controversial data in the literature about the role of neutrophils in Leishmania infection, principally when different routes of inoculation are involved. Considering the relevance of these cells to ROS production and predicting important alterations of ROS effect when the inoculation route is changed, we compared the innate immune response generated on the most common used routes of parasite inoculation, the subcutaneous and the intradermal routes. However, we used the model of L. major infection, since this model is better established in the literature. Starting at 2h p.i., intradermal infection with L. major presented massive neutrophil recruitment and higher mRNA expression of CXCL-1 followed by intense recruitment of Ly6Chi inflammatory monocytes at 48h and 9 days p.i. compared to subcutaneous infection. This more intense inflammatory profile observed at the infected intradermal site also was accompanied by a more efficient parasite capture in this site. We observed a 10-fold increase in the number of infected cells at the times measured. In contrast, dendritic cells and macrophages represented the majority of infected cells in the subcutaneous site. Due this confirmed and important participation of neutrophils in the intradermal infection, we utilized this route of inoculation to determine the influence of ROS in our model of L. amazonensis infection. When infected intradermally, gp91phox-/- mice presented larger lesions starting at 4 weeks p.i. and a high degree of inflammation leading to a dense necrotic area and tissue loss without differences in parasite loads. Surprisingly, the levels of inflammatory cytokines did not change during the course of infection, but we did detect a large accumulation of neutrophils at the intradermal site. Increased neutrophil numbers in gp91phox-/- mice was associated with higher numbers and frequencies of necrotic neutrophils at 8 weeks p.i. and may be the major factor responsible for the inflammatory phenotype observed in these mice. These experiments suggest that oxygen radicals have an important role in L. amazonensis infection, controlling neutrophil flux to the lesion, impairing necrotic inflammatory death in these cells and consequently the inflammation of infected tissue. Moreover, the route of inoculation greatly influences the effect of reactive oxygen species (ROS) in L. amazonensis infection, since the major cells producing ROS, the neutrophils, play a prominent role only in intradermal infection. This is the first report to show the effect of ROS in Leishmania model closest to natural infection, indicating a more physiological way to study ROS in Leishmania infections.