1,907 research outputs found
Radiation-resistant device phenomena
Electrical properties of reactively evaporated aluminum oxide films and electron mean free path through metal fil
Adjunctive strategies in the management of resistant, 'undilatable' coronary lesions after successfully crossing a CTO with a guidewire.
Successful revascularisation of chronic total occlusions (CTOs) remains one of the greatest challenges in the era of contemporary percutaneous coronary intervention (PCI). Such lesions are encountered with increasing frequency in current clinical practice. A predictable increase in the future burden of CTO management can be anticipated given the ageing population, increased rates of renal failure, graft failure and diabetes mellitus. Given recent advances and developments in CTO PCI management, successful recanalisation can be anticipated in the majority of procedures undertaken at high-volume centres when performed by expert operators. Despite advances in device technology, the management of resistant, calcific lesions remains one of the greatest challenges in successful CTO intervention. Established techniques to modify calcific lesions include the use of high-pressure non-compliant balloon dilation, cutting-balloons, anchor balloons and high speed rotational atherectomy (HSRA). Novel approaches have proven to be safe and technically feasible where standard approaches have failed. A step-wise progression of strategies is demonstrated, from well-recognised techniques to techniques that should only be considered when standard manoeuvres have proven unsuccessful. These methods will be described in the setting of clinical examples and include use of very high-pressure non-compliant balloon dilation, intentional balloon rupture with vessel dissection or balloon assisted micro-dissection (BAM), excimer coronary laser atherectomy (ECLA) and use of HSRA in various 'offlabel' settings
The Political Economy of Low-carbon Investments: Insights from the Wind and Solar Power Sectors in India
The primary motivation behind this research is the need to accelerate the supply of renewable energy because of the important role that it plays in mitigating climate change and in fostering sustainable development.
Understanding past drivers for low-carbon investment can help us identify those for the future, and what could accelerate such investment. Investment in renewable energy can be modelled as a problem of technical asset allocation or optimisation at the firm or sectoral level, but is not entirely explained by this approach – the context in which actors are involved, their motivations and the wider systems in which they operate must also be taken into account. The interactions between actors may sometimes accelerate investment and sometimes prevent it; however, understanding the dynamics of these processes is crucial if we are to shape them. This study, which focuses on the wind and solar power sectors in India and China, aims to find and compare drivers for investment in renewable energy.
Our point of entry for this piece of the study is that India is already seeing significant investment activity in renewable energy. During 2010/11, investment in renewables grew by 62 per cent to US6.5bn). In 2010 the Indian government announced a National Solar Mission that aimed to add 20 gigawatts (GW) of solar power generation capacity by 2020; wind power capacity has grown steadily at a compound annual growth rate of 17.9 per cent since 2007 and now contributes more than 20GW, or just over 70 per cent, of total renewable energy capacity. Almost all of this is private investment. However, these levels will need to increase sharply in the coming years and decades if India is to reach China’s levels (who, in 2013, became the world leader with US1tn needed.UK Department for International Developmen
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A Technical Focus on Antegrade Dissection and Re-entry for Coronary Chronic Total Occlusions: a Practice Update for 2019.
Coronary chronic total occlusions (CTOs) are a commonly encountered lesion. These present in a diverse patient population with variable anatomy. Technical success rates of ~90% are achievable for CTO lesions in centers with appropriate expertise. Many lesions can be crossed with wire-based techniques. However, the most anatomically complex and technically challenging lesions will often require more advanced approaches such as retrograde access and/or the application of blunt dissection techniques in the vessel to safely navigate long and/or ambiguous CTO segments. Retrograde dissection and re-entry (RDR) and antegrade dissection and re-entry (ADR) strategies are often needed to treat such lesions. In many circumstances, ADR offers a safe and efficient means to successfully cross a CTO lesion. Therefore, operators must remain cognizant of the risks and benefits of differing technical approaches during CTO percutaneous coronary intervention, particularly when both ADR and RDR are feasible. This article provides an overview of the ADR technique in addition to updated approaches in contemporary clinical practice
What Drives Wind and Solar Energy Investment in India and China?
This research is motivated by the need to transform the basis of energy systems from fossil fuels to renewable sources. As well as the imperative of climate change, this transformation is needed to create development trajectories for economies that are genuinely sustainable over the long term. Our objectives are therefore both environmental and developmental.
Understanding what drove low-carbon investments in the past is the key to identifying the drivers of investment in the future. In this regard, low-carbon investment decisions are not technical questions of optimal asset allocation. Rather, understanding these decisions requires an approach rooted in political economy, which assesses the motivations and incentives of the different actors involved, and how these interact. Understanding the dynamics of this process is the first step in shaping it.
This research concentrates on private investment. Of the US1 trillion, half of which will fund the replacement of existing technologies, largely in developed countries. The remaining US400bn pa) will be in developing countries (IEA 2008).
Our focus is on the determinants of low-carbon investment in the world’s two largest emerging economies: China and India. While these countries are responsible for the biggest growth in carbon emissions, China is now the largest global investor in renewable energy and India saw the highest growth rate in recent times between 2010 and 2011 (BNEF 2012).UK Department for International Developmen
Inclusion Policies in Two UK Countries : vernacular responses to global influence
publishedVersio
Appropriate inclusion of interactions was needed to avoid bias in multiple imputation
OBJECTIVE: Missing data are a pervasive problem, often leading to bias in complete records analysis (CRA). Multiple imputation (MI) via chained equations is one solution, but its use in the presence of interactions is not straightforward. STUDY DESIGN AND SETTING: We simulated data with outcome Y dependent on binary explanatory variables X and Z and their interaction XZ. Six scenarios were simulated (Y continuous and binary, each with no interaction, a weak and a strong interaction), under five missing data mechanisms. We use directed acyclic graphs to identify when CRA and MI would each be unbiased. We evaluate the performance of CRA, MI without interactions, MI including all interactions, and stratified imputation. We also illustrated these methods using a simple example from the National Child Development Study (NCDS). RESULTS: MI excluding interactions is invalid and resulted in biased estimates and low coverage. When XZ was zero, MI excluding interactions gave unbiased estimates but overcoverage. MI including interactions and stratified MI gave equivalent, valid inference in all cases. In the NCDS example, MI excluding interactions incorrectly concluded there was no evidence for an important interaction. CONCLUSIONS: Epidemiologists carrying out MI should ensure that their imputation model(s) are compatible with their analysis model
Adverse events in radiation oncology: A case series from wake up safe, the pediatric anesthesia quality improvement initiative
BackgroundRadiation therapy in pediatric patients often requires anesthesia and poses environmental challenges. Monitoring must be done remotely to limit radiation exposure to the provider. Airway access can be limited by masks or frames. Care is often delivered in relatively inaccessible locations in the hospital. While individual institutions have reported their outcomes, this case series aims to review a multicenter registry of significant adverse events and make recommendations for improved care.MethodsWake Up Safe: The Pediatric Quality Improvement Initiative maintains a multisite, voluntary registry of pediatric perianesthetic significant adverse events. This was queried for reports from radiation oncology from January 1, 2010 to May 10, 2018. The database contained 3,379 significant adverse events from approximately 3.3 million anesthetics. All 33 institutions submitted data on a standardized form to a central data repository (Axio Research, Seattle Washington). Prior to each significant adverse events case submission, three anesthesiologists who were not involved in the event analyzed the event using a standardized root cause analysis method to identify the causal or contributing factor(s).ResultsSix significant adverse events were identified. In three, incorrect programming of a propofol infusion resulted in overdose. In case one, the 3â yearâ old female became hypotensive, requiring vasopressors and volume resuscitation. In the second, the 2â yearâ old female experienced airway obstruction and apnea requiring chin lift. In case three, the child suffered no consequences despite a noted overdose of propofol infusion. In case four, a 2â yearâ old female with recent respiratory infection suffered laryngospasm during an unmonitored transport to the recovery area. She developed profound oxygen desaturation with bradycardia treated with succinylcholine and chest compressions. In case five, a 6â yearâ old former premature child suffered laryngospasm at the conclusion of mask creation under general anesthesia with a laryngeal mask airway. The radiation mask delayed recognition of copious secretions. Finally, in case six, a 6â yearâ old undergoing stereotactic radiosurgery in a head halo suffered bronchospasm and unintended extubation during therapy which required multiple attempts at reintubation by multiple providers ultimately requiring cancellation of the treatment and transport to the intensive care unit.ConclusionThere were few radiation oncology significant adverse events, but analysis has led to the identification of several specific opportunities for improvement in pediatric anesthesia for radiation oncology.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/148238/1/pan13567_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/148238/2/pan13567.pd
p19/Arf and p53 suppress sentinel lymph node lymphangiogenesis and carcinoma metastasis.
The ability of tumor cells to metastasize is increasingly viewed as an interaction between the primary tumor and host tissues. Deletion of the p19/Arf or p53 tumor suppressor genes accelerates malignant progression and metastatic spread of 7,12-dimethylbenz(a)anthracene (DMBA)/12-O-tetradecanoyl-phorbol-13-acetate (TPA)-induced squamous cell carcinomas, providing a model system to address mechanisms of metastasis. Here, we show that benign pre-metastatic papillomas from wild-type mice trigger lymphangiogenesis within draining lymph nodes, whereas there is no growth of primary tumor lymphatic vessels. Lymph node lymphangiogenesis is greatly accelerated in papilloma-bearing p19/Arf- or p53-deficient mice, which coincides with the greater propensity of these tumors to progress to carcinomas and to metastasize. The extent of accumulation of B cells within the tumor-draining lymph nodes of wild-type mice predicted the level of lymph node lymphangiogenesis and metastatic potential. Arf or p53 deficiency strongly accelerated lymph node immune cell accumulation, in a manner that was associated with the extent of lymph node lymphatic sinus growth. This immune cell accumulation and lymph node lymphangiogenesis phenotype identifies host anti-tumor responses that could drive metastatic spread of cancers via the lymphatics
Normalization factors for magnetic relaxation of small particle systems in non-zero magnetic field
We critically discuss relaxation experiments in magnetic systems that can be
characterized in terms of an energy barrier distribution, showing that proper
normalization of the relaxation data is needed whenever curves corresponding to
different temperatures are to be compared. We show how these normalization
factors can be obtained from experimental data by using the
scaling method without making any assumptions about the nature of the energy
barrier distribution. The validity of the procedure is tested using a
ferrofluid of Fe_3O_4 particles.Comment: 5 pages, 6 eps figures added in April 22, to be published in Phys.
Rev. B 55 (1 April 1997
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