2,005 research outputs found
Electrochemical synthesis of copper(i) acetylides: Via simultaneous copper ion and catalytic base electrogeneration for use in click chemistry
We report an efficient and sustainable electrochemical synthesis of copper(i) acetylides using simultaneous copper oxidation and Hofmann elimination of quaternary ammonium salts. The electrochemically-generated base was also regenerated electrochemically, making it catalytic. A 'Click test' (CuAAC reaction) was performed to assess product purity and an electrochemically-promoted, one-pot CuAAC reaction was performed, which serves as a promising initial demonstration of this approach in a pharmaceutically-relevant reaction
Development of probabilistic models for quantitative pathway analysis of plant pest introduction for the EU territory
This report demonstrates a probabilistic quantitative pathway analysis model that can be used in risk assessment for plant pest introduction into EU territory on a range of edible commodities (apples, oranges, stone fruits and wheat). Two types of model were developed: a general commodity model that simulates distribution of an imported infested/infected commodity to and within the EU from source countries by month; and a consignment model that simulates the movement and distribution of individual consignments from source countries to destinations in the EU. The general pathway model has two modules. Module 1 is a trade pathway model, with a Eurostat database of five years of monthly trade volumes for each specific commodity into the EU28 from all source countries and territories. Infestation levels based on interception records, commercial quality standards or other information determine volume of infested commodity entering and transhipped within the EU. Module 2 allocates commodity volumes to processing, retail use and waste streams and overlays the distribution onto EU NUTS2 regions based on population densities and processing unit locations. Transfer potential to domestic host crops is a function of distribution of imported infested product and area of domestic production in NUTS2 regions, pest dispersal potential, and phenology of susceptibility in domestic crops. The consignment model covers the several routes on supply chains for processing and retail use. The output of the general pathway model is a distribution of estimated volumes of infested produce by NUTS2 region across the EU28, by month or annually; this is then related to the accessible susceptible domestic crop. Risk is expressed as a potential volume of infested fruit in potential contact with an area of susceptible domestic host crop. The output of the consignment model is a volume of infested produce retained at each stage along the specific consignment trade chain
Post-mortem information management: exploring contextual factors in appropriate personal data access after death
\ua9 2024 The Author(s). Published with license by Taylor & Francis Group, LLC.With the increasing size and complexity of personal information and data landscapes, there is a need for guidance and support in the appropriate management of a deceased person’s postmortem privacy and digital legacy. However, most people engage poorly with existing mechanisms for specifying and planning for access and suitable usage of their own data. We report on two studies exploring the ways in which contextual factors such as the accessor and the data type may affect the appropriateness of personal data flows differently during life and after death. Our findings indicate that suitable data access after death is highly individual and contextual, with differences in appropriateness between during-life and after-death data flows significantly affected by the accessor and the data type in question. We identify that ambiguous accessor motivation, failure to communicate intent, changing temporal context and latent data values further complicate the act of digital legacy planning. Our findings also provide further evidence for the existence of a postmortem privacy paradox in which reported user behaviors do not reflect intent. With this in mind, we offer design recommendations for the integration of digital legacy planning functionality within Personal Information Management (PIM) and Group Information Management (GIM) systems
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Effect of Endovascular Aneurysm Repair on the Volume-Outcome Relationship in Aneurysm Repair
Background— We aim to quantify the relationship between the annual caseload (volume) and outcome from elective endovascular (EVR) or open repair of abdominal aortic aneurysms (AAAs) in England between 2005 and 2007.
Methods and Results— Individual patient data were obtained from the Hospital Episode Statistics. Statistical methods included multiple logistic regression models, mortality control charts, and safety plots to determine the nature of any relationship between volume and outcome. The case-mix between hospitals of different sizes was examined using observed and expected values for in-hospital mortality. Outcome measures included in-hospital mortality and hospital length of stay. Between 2005 and 2007, a total of 57 587 patients were admitted to hospitals in England with a diagnosis of AAA, and 11 574 underwent AAA repair. There were 7313 elective AAA repairs, of which 5668 (78%) were open and 1645 (22%) were EVR. In-hospital mortality rates were 5.63% for all elective AAA repairs with rates of 6.18% for open repair and 3.77% for EVR (odds ratio, 0.676; 95% CI, 0.501 to 0.913; P=0.011). High-volume aneurysm services were associated with significantly lower mortality rates overall (0.991; 0.988 to 0.994; P<0.0001), for open repairs (0.994; 0.991 to 0.998; P=0.0008), and EVR (0.989; 0.982 to 0.995; P=0.0007). Large endovascular units had low mortality rates for open repairs.
Conclusion— A strong relationship existed between the volume of surgery performed and outcome from both open and endovascular aneurysm repairs. These data support the concept that abdominal aortic surgery should be performed in specialized units that meet a minimum volume threshold
Electrochemical Preparation and Applications of Copper(I) Acetylides: A Demonstration of How Electrochemistry Can Be Used to Facilitate Sustainability in Homogeneous Catalysis
Copper(I) acetylides are important intermediates for many syntheses and have been prepared here electrochemically in an energy efficient manner. These were subsequently employed in simple organic C–C bond forming reactions. We also demonstrate that application of Faraday's laws allows the charge to be calculated so that only the required amount of metal is used. In addition, the application of copper-coated graphite electrodes allows the maximum atom efficiency for this process and even offers a recovery strategy to extract the metal following completion of the reaction
Investigations Into the Mechanism of Copper-Mediated Glaser-Hay Couplings Using Electrochemical Techniques
The mechanism of the copper mediated C-C bond forming reaction known as Glaser-Hay coupling (alkyne dimerization) has been investigated using electrochemical techniques. Applying an oxidative potential to a copper or copper-coated graphite electrode in the presence of the organic base DABCO results in the dimerization of phenylacetylene in good yield. Further mechanistic investigation has shown that this reaction medium results in the assembly of a dinuclear Cu(I) complex which, although previously reported, has never been shown to have catalytic properties for C-C bond formation. The complex is reminiscent of that proposed in the Bohlmann model for the Glaser-Hay reaction and as such lends weight to this proposed mechanism above the alternative proposed mononuclear catalytic cycle
Cardiac rehabilitation versus standard care after aortic aneurysm repair (Aneurysm CaRe): study protocol for a randomised controlled trial.
BACKGROUND: Abdominal and thoracic aortic aneurysms (A/TAA) are an important cause of mortality amongst the older population. Although A/TAA repair can be performed with low peri-operative risk, overall life expectancy remains poor in the years that follow surgery. The majority of deaths are caused by heart attack or stroke, which can both be prevented by cardiac rehabilitation (CR) in patients with clinically-manifest coronary artery disease. A Cochrane review has urged researchers to widen the use of CR to other populations with severe cardiovascular risk, and patients surviving A/TAA repair appear ideal candidates. However, it is unknown whether CR is feasible or acceptable to A/TAA patients, who are a decade older than those currently enrolling in CR. Aneurysm-CaRe is a feasibility randomised controlled trial (RCT) that will address these issues. METHODS AND DESIGN: Aneurysm-CaRe is a pilot RCT of CR versus standard care after A/TAA repair, with the primary objectives of estimating enrolment to a trial of CR after A/TAA repair and estimating compliance with CR amongst patients with A/TAA. Aneurysm-CaRe will randomise 84 patients at two sites. Patients discharged from hospital after elective A/TAA repair will be randomised to standard care or enrolment in their local CR programme with a protocolised approach to medical cardiovascular risk reduction. The primary outcome measures are enrolment in the RCT and compliance with CR. Secondary outcomes will include phenotypic markers of cardiovascular risk and smoking cessation, alongside disease-specific and generic quality-of-life measures. TRIAL REGISTRATION: ISRCTN 65746249 5 June 2014
Targeted Assembly of Short Sequence Reads
As next-generation sequence (NGS) production continues to increase, analysis is becoming a significant bottleneck. However, in situations where information is required only for specific sequence variants, it is not necessary to assemble or align whole genome data sets in their entirety. Rather, NGS data sets can be mined for the presence of sequence variants of interest by localized assembly, which is a faster, easier, and more accurate approach. We present TASR, a streamlined assembler that interrogates very large NGS data sets for the presence of specific variants, by only considering reads within the sequence space of input target sequences provided by the user. The NGS data set is searched for reads with an exact match to all possible short words within the target sequence, and these reads are then assembled strin-gently to generate a consensus of the target and flanking sequence. Typically, variants of a particular locus are provided as different target sequences, and the presence of the variant in the data set being interrogated is revealed by a successful assembly outcome. However, TASR can also be used to find unknown sequences that flank a given target. We demonstrate that TASR has utility in finding or confirming ge-nomic mutations, polymorphism, fusion and integration events. Targeted assembly is a powerful method for interrogating large data sets for the presence of sequence variants of interest. TASR is a fast, flexible and easy to use tool for targeted assembly
Trophic Garnishes: Cat–Rat Interactions in an Urban Environment
BACKGROUND:Community interactions can produce complex dynamics with counterintuitive responses. Synanthropic community members are of increasing practical interest for their effects on biodiversity and public health. Most studies incorporating introduced species have been performed on islands where they may pose a risk to the native fauna. Few have examined their interactions in urban environments where they represent the majority of species. We characterized house cat (Felis catus) predation on wild Norway rats (Rattus norvegicus), and its population effects in an urban area as a model system. Three aspects of predation likely to influence population dynamics were examined; the stratum of the prey population killed by predators, the intensity of the predation, and the size of the predator population. METHODOLOGY/PRINCIPAL FINDINGS:Predation pressure was estimated from the sizes of the rat and cat populations, and the characteristics of rats killed in 20 alleys. Short and long term responses of rat population to perturbations were examined by removal trapping. Perturbations removed an average of 56% of the rats/alley but had no negative long-term impact on the size of the rat population (49.6+/-12.5 rats/alley and 123.8+/-42.2 rats/alley over two years). The sizes of the cat population during two years (3.5 animals/alley and 2.7 animals/alley) also were unaffected by rat population perturbations. Predation by cats occurred in 9/20 alleys. Predated rats were predominantly juveniles and significantly smaller (144.6 g+/-17.8 g) than the trapped rats (385.0 g+/-135.6 g). Cats rarely preyed on the larger, older portion of the rat population. CONCLUSIONS/SIGNIFICANCE:The rat population appears resilient to perturbation from even substantial population reduction using targeted removal. In this area there is a relatively low population density of cats and they only occasionally prey on the rat population. This occasional predation primarily removes the juvenile proportion of the rat population. The top predator in this urban ecosystem appears to have little impact on the size of the prey population, and similarly, reduction in rat populations doesn't impact the size of the cat population. However, the selected targeting of small rats may locally influence the size structure of the population which may have consequences for patterns of pathogen transmission
Time preferences and risk aversion: tests on domain differences
The design and evaluation of environmental policy requires the incorporation of time and risk elements as many environmental outcomes extend over long time periods and involve a large degree of uncertainty. Understanding how individuals discount and evaluate risks with respect to environmental outcomes is a prime component in designing effective environmental policy to address issues of environmental sustainability, such as climate change. Our objective in this study is to investigate whether subjects' time preferences and risk aversion across the monetary domain and the environmental domain differ. Crucially, our experimental design is incentivized: in the monetary domain, time preferences and risk aversion are elicited with real monetary payoffs, whereas in the environmental domain, we elicit time preferences and risk aversion using real (bee-friendly) plants. We find that subjects' time preferences are not significantly different across the monetary and environmental domains. In contrast, subjects' risk aversion is significantly different across the two domains. More specifically, subjects (men and women) exhibit a higher degree of risk aversion in the environmental domain relative to the monetary domain. Finally, we corroborate earlier results, which document that women are more risk averse than men in the monetary domain. We show this finding to, also, hold in the environmental domain
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