1,080 research outputs found
Innovation in Commercial Supersonic Aircraft with Candidate Engine for Next Generation Supersonic Aircraft
The objective of this design study and competition - Next Generation Supersonic Candidate Engine and Aircraft Design, is a response to a proposal and is motivated by NASAâs National Research Announcement in 2006. The requirements of this design study are provided by AIAA (American Institute of Aeronautics and Astronautics). The aircraft designed is a private business class. The aircraft engine performs at a maximum speed of Mach 1.8 and supersonic cruise speed of Mach 1.6 at 55,000 feet and a range of 4000 nmi. A generated mission profile through considerations in flight regime will drive the design involved in the development of aircraft characteristics. Interior cabin configurations are expected to support seating for up to 100 passengers. Using parametric cycle analysis, computational fluid dynamics, and system modeling/experimentation, a refined aircraft and engine design will be produced. Detailed analyses to meet the baseline requirements involve interpretation of trends of current generation aircraft engines are considered for the finalized design. The performance of the aircraft engine will involve calculations on wave drag, supersonic turbulent flow, and integrated methods of design of the nacelle enveloped within the aircraft fuselage. Through these various iterative methods, considerations in supersonic aircraft propulsion and aircraft design are presented. Projected technical specifications are to be implemented for the next generation of supersonic aircraft expected to be debuted in 2025. A robust composition of advanced material composites, methods of manufacturing, and forecasted advancements in technology are utilized to develop a proposal for the next generation of supersonic aircraft
Electrochemical nanoreactor provides a comprehensive view of isocitrate dehydrogenase cancer-drug kinetics
The ability to control enzyme cascades entrapped in a nanoporous electrode material (the âElectrochemical Leafâ, e-Leaf) has been exploited to gain detailed kinetic insight into the mechanism of an anti-cancer drug. Ivosidenib, used to treat acute myeloid leukemia, acts on a common cancer-linked variant of isocitrate dehydrogenase 1 (IDH1 R132H) inhibiting its âgain-of-functionâ activityâthe undesired reduction of 2-oxoglutarate (2OG) to the oncometabolite 2-hydroxyglutarate (2HG). The e-Leaf quantifies the kinetics of IDH1 R132H inhibition across a wide and continuous range of conditions, efficiently revealing factors underlying the inhibitor residence time. Selective inhibition of IDH1 R132H by Ivosidenib and another inhibitor, Novartis 224, is readily resolved as a two-stage process whereby initial rapid non-inhibitory binding is followed by a slower step to give the inhibitory complex. These kinetic features are likely present in other allosteric inhibitors of IDH1/2. Such details, essential for understanding inhibition mechanisms, are not readily resolved in conventional steady-state kinetics or by techniques that rely only on measuring binding. Extending the new method and analytical framework presented here to other enzyme systems will be straightforward and should rapidly reveal insight that is difficult or often impossible to obtain using other methods
Selective Use of Pericardial Window and Drainage as Sole Treatment for Hemopericardium from Penetrating Chest Trauma
Background
Penetrating cardiac injuries (PCIs) are highly lethal, and a sternotomy is considered mandatory for suspected PCI. Recent literature suggests pericardial window (PCW) may be sufficient for superficial cardiac injuries to drain hemopericardium and assess for continued bleeding and instability. This study objective is to review patients with PCI managed with sternotomy and PCW and compare outcomes.
Methods
All patients with penetrating chest trauma from 2000 to 2016 requiring PCW or sternotomy were reviewed. Data were collected for patients who had PCW for hemopericardium managed with only pericardial drain, or underwent sternotomy for cardiac injuries grade 1â3 according to the American Association for the Surgery of Trauma (AAST) Cardiac Organ Injury Scale (OIS). The PCW+drain group was compared with the Sternotomy group using Fisherâs exact and Wilcoxon rank-sum test with P\u3c0.05 considered statistically significant.
Results
Sternotomy was performed in 57 patients for suspected PCI, including 7 with AAST OIS grade 1â3 injuries (Sternotomy group). Four patients had pericardial injuries, three had partial thickness cardiac injuries, two of which were suture-repaired. Average blood drained was 285mL (100â500 mL). PCW was performed in 37 patients, and 21 had hemopericardium; 16 patients proceeded to sternotomy and 5 were treated with pericardial drainage (PCW+drain group). All PCW+drain patients had suction evacuation of hemopericardium, pericardial lavage, and verified bleeding cessation, followed by pericardial drain placement and admission to intensive care unit (ICU). Average blood drained was 240mL (40â600 mL), and pericardial drains were removed on postoperative day 3.6 (2â5). There was no significant difference in demographics, injury mechanism, Revised Trauma Score exploratory laparotomies, hospital or ICU length of stay, or ventilator days. No in-hospital mortality occurred in either group.
Conclusions
Hemodynamically stable patients with penetrating chest trauma and hemopericardium may be safely managed with PCW, lavage and drainage with documented cessation of bleeding, and postoperative ICU monitoring.
Level of evidence
Therapeutic study, level IV
The atypical chemokine receptor Ackr2 constrains NK cell migratory activity and promotes metastasis
Chemokines have been shown to be essential players in a range of cancer contexts. In this study, we demonstrate that mice deficient in the atypical chemokine receptor Ackr2 display impaired development of metastasis in vivo in both cell line and spontaneous models. Further analysis reveals that this relates to increased expression of the chemokine receptor CCR2, specifically by KLRG1+ NK cells from the Ackr2â/â mice. This leads to increased recruitment of KLRG1+ NK cells to CCL2-expressing tumors and enhanced tumor killing. Together, these data indicate that Ackr2 limits the expression of CCR2 on NK cells and restricts their tumoricidal activity. Our data have important implications for our understanding of the roles for chemokines in the metastatic process and highlight Ackr2 and CCR2 as potentially manipulable therapeutic targets in metastasis
A new tram network for Bristol:a possible scenario?
Some UK cities have seen the successful reintroduction of trams to complement and improve public transport services. This paper investigates the impact a hypothetical tramline would have in Bristol. This study was conducted in light of proposals for a bus rapid transit (BRT) network in Bristol. The literature review undertaken concludes that while BRT systems tend to have lower capital costs, a tram system could also be considered. At near-capacity operation, trams may be more effective in encouraging a modal shift away from travelling by car. Evidence from a preliminary simulation model, which was built to evaluate the demand a hypothetical tramline from the airport to the city centre would attract, suggests that a tram would encourage users to switch to public transport. Suggestions for further work for model refinement coupled with better understanding system impacts of the proposed tram system are included. </jats:p
Extensive hydrogen supersaturations in the western South Atlantic Ocean suggest substantial underestimation of nitrogen fixation
The nitrogen cycle is fundamental to Earth's biogeochemistry. Yet major uncertainties of quantification remain, particularly regarding the global oceanic nitrogen fixation rate. Hydrogen is produced during nitrogen fixation and will become supersaturated in surface waters if there is net release from diazotrophs. Ocean surveys of hydrogen supersaturation thus have the potential to illustrate the spatial and temporal distribution of nitrogen fixation, and to guide the far more onerous but quantitative methods for measuring it. Here we present the first transect of high resolution measurements of hydrogen supersaturations in surface waters along a meridional 10,000 km cruise track through the Atlantic. We compare measured saturations with published measurements of nitrogen fixation rates and also with model-derived values. If the primary source of excess hydrogen is nitrogen fixation and has a hydrogen release ratio similar to Trichodesmium, our hydrogen measurements would point to similar rates of fixation in the North and South Atlantic, roughly consistent with modelled fixation rates but not with measured rates, which are lower in the south. Possible explanations would include any substantial nitrogen fixation by newly discovered diazotrophs, particularly any having a hydrogen release ratio similar to or exceeding that of Trichodesmium; under-sampling of nitrogen fixation south of the equator related to excessive focus on Trichodesmium; and methodological shortcomings of nitrogen fixation techniques that cause a bias towards colonial diazotrophs relative to unicellular forms. Alternatively our data are affected by an unknown hydrogen source that is greater in the southern half of the cruise track than the northern
Sustaining sexual and reproductive health through COVID-19 pandemic restrictions: qualitative interviews with Australian clinicians
Background. The sexual and reproductive health care of people with HIV and those at risk of HIV
has largely been delivered face-to-face in Australia. These services adapted to the coronavirus
disease 2019 (COVID-19) pandemic with a commitment to continued care despite major
impacts on existing models and processes. Limited attention has been paid to understanding the
perspectives of the sexual and reproductive health care workforce in the research on COVID-19
adaptations. Methods. Semi-structured interviews were conducted between June and September
2021 with 15 key informants representing a diverse range of service settings and professional roles in
the Australian sexual and reproductive health sector. Inductive themes were generated through a
process of reflexive thematic analysis, informed by our deductive interest in clinical adaptations.
Results. The major adaptations were: triage (rapidly adapting service models to protect the
most essential forms of care); teamwork (working together to overcome ongoing threats to
service quality and staff wellbeing), and the intwined themes of telehealth and trust (remaining
connected to marginalised communities through remote care). Despite impacts on care models
and client relationships, there were sustained benefits from the scaleup of remote care, and
attention to service safety, teamwork and communication. Conclusions. Attending to the
experiences of those who worked at the frontline of the COVID-19 response provides essential
insights to inform sustained, meaningful system reform over time. The coming years will provide
important evidence of longer-term impacts of COVID-19 interruptions on both the users and
providers of sexual and reproductive health services
Urinary Levoglucosan as a Biomarker of Wood Smoke Exposure: Observations in a Mouse Model and in Children
BACKGROUND: Biomass smoke is an important source of particulate matter (PM), and much remains to be discovered with respect to the human health effects associated with this specific PM source. Exposure to biomass smoke can occur in one of two main categories: short-term exposures consist of periodic, seasonal exposures typified by communities near forest fires or intentional agricultural burning, and long-term exposures are chronic and typified by the use of biomass materials for cooking or heating. Levoglucosan (LG), a sugar anhydride released by combustion of cellulose-containing materials, is an attractive candidate as a biomarker of wood smoke exposure. OBJECTIVES: In the present study, Balb/c mice and children were assessed for LG in urine to determine its feasibility as a biomarker. METHODS: We performed urinary detection of LG by gas chromatography/mass spectrometry after intranasal instillations of LG or concentrated PM (mice) or biomass exposure (mice or humans). RESULTS: After instillation, we recovered most of the LG within the first 4 hr. Experiments using glucose instillation proved the specificity of our system, and instillation of concentrated PM from wood smoke, ambient air, and diesel exhaust supported a connection between wood smoke and LG. In addition, LG was detected in the urine of mice exposed to wood smoke. Finally, a pilot human study proved our ability to detect LG in urine of children. CONCLUSIONS: These results demonstrate that LG in the lungs is detectable in the urine of both mice and humans and that it is a good candidate as a biomarker of exposure to biomass smoke
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