The Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) method is a simple and straightforward extraction technique involving an initial partitioning followed by an extract clean-up using ...dispersive solid-phase extraction (d-SPE). Originally, the QuEChERS approach was developed for recovering pesticide residues from fruits and vegetables, but rapidly gained popularity in the comprehensive isolation of analytes from different matrices. According to PubMed, since its development in 2003 up to November 2018, about 1360 papers have been published reporting QuEChERS as extraction method. Several papers have reported different improvements and modifications to the original QuEChERS protocol to ensure more efficient extractions of pH-dependent analytes and to minimize the degradation of labile analytes. This analytical approach shows several advantages over traditional extraction techniques, requiring low sample and solvent volumes, as well as less time for sample preparation. Furthermore, most of the published studies show that the QuEChERS protocol provides higher recovery rate and a better analytical performance than conventional extraction procedures.
This review proposes an updated overview of the most recent developments and applications of QuEChERS beyond its original application to pesticides, mycotoxins, veterinary drugs and pharmaceuticals, forensic analysis, drugs of abuse and environmental contaminants. Their pros and cons will be discussed, considering the factors influencing the extraction efficiency. Whenever possible, the performance of the QuEChERS is compared to other extraction approaches. In addition to the evolution of this technique, changes and improvements to the original method are discussed.
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•Modification and miniaturization of QuEChERS method.•An updated overview of the most recent QuEChERS applications.•QuEChERS combined with GC- and LC-MS/MS provided low detection limits and high recoveries.•QuEChERS performance compared to other extraction approaches.
Lithium solid electrolytes can potentially address two key limitations of the organic electrolytes used in today's lithium-ion batteries, namely, their flammability and limited electrochemical ...stability. However, achieving a Li(+) conductivity in the solid state comparable to existing liquid electrolytes (>1 mS cm(-1)) is particularly challenging. In this work, we reveal a fundamental relationship between anion packing and ionic transport in fast Li-conducting materials and expose the desirable structural attributes of good Li-ion conductors. We find that an underlying body-centred cubic-like anion framework, which allows direct Li hops between adjacent tetrahedral sites, is most desirable for achieving high ionic conductivity, and that indeed this anion arrangement is present in several known fast Li-conducting materials and other fast ion conductors. These findings provide important insight towards the understanding of ionic transport in Li-ion conductors and serve as design principles for future discovery and design of improved electrolytes for Li-ion batteries.
There is large heterogeneity in approaches to tackling nosocomial outbreaks caused by carbapenemase-producing Enterobacterales (CPE), however there is limited guidance on how to approach their ...management. Rapid and robust infection prevention and control interventions can be effective in preventing and reducing the impact of outbreaks in healthcare environments. We present a stepwise approach to aspects of CPE outbreak management, including the development of an action plan, engagement and communication with key stakeholders, developing a dynamic risk assessment, and staff education. These can provide a blueprint for organisations to create templates and checklists to inform their own outbreak response.
Abstract
In this research, improved design for the lifting slide rail system on stone processing machine has innovated in a few aspects, including the innovative design of the lifting rail, fixture ...to fix and connect with the hydraulic tappet, and the sliding block equipped with limit device etc. The improved design has been successfully applied to the stone processing machine to crush and process block and stone flake processing waste of different shapes, it turned out that the needle flake particle content and crushing index of the processed stone are in line with the national standard requirements, i.e. crushing index of 7.2%, reaching the technical requirements of Class I crushed stone. In another words, the improved design has significantly improved the processing efficiency and safety and reduced costs effectively; meanwhile, its handy operation and utilization has made it ready to promote in a wider range.
Abstract
Despite highly promising characteristics of three-dimensionally (3D) nanostructured catalysts for the oxygen evolution reaction (OER) in polymer electrolyte membrane water electrolyzers ...(PEMWEs), universal design rules for maximizing their performance have not been explored. Here we show that woodpile (WP)-structured Ir, consisting of 3D-printed, highly-ordered Ir nanowire building blocks, improve OER mass activity markedly. The WP structure secures the electrochemically active surface area (ECSA) through enhanced utilization efficiency of the extended surface area of 3D WP catalysts. Moreover, systematic control of the 3D geometry combined with theoretical calculations and various electrochemical analyses reveals that facile transport of evolved O
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gas bubbles is an important contributor to the improved ECSA-specific activity. The 3D nanostructuring-based improvement of ECSA and ECSA-specific activity enables our well-controlled geometry to afford a 30-fold higher mass activity of the OER catalyst when used in a single-cell PEMWE than conventional nanoparticle-based catalysts.
With increasing concerns on customer requirements (CRs) in product improvement, the research of integrating product scenarios into CRs analysis has attracted the attention of designers. ...Importance-performance-analysis (IPA), which can be used to represent the relationship between CR importance and product performance, is a well-known model for analyzing CRs. However, a major challenge of the IPA model is the quantification of the importance of CRs accurately. Network analysis (NA) is an appropriate method to understand and calculate the importance of CRs in different usage scenarios. This research presents a Network Analysis-Importance Performance Analysis (NA-IPA) model that integrates NA with the IPA model to improve product design through mapping CRs to configuration plans. Accordingly, two mechanisms are integrated to support product design improvement, namely, (1) the classifier of the NA-IPA model is used to categorise CRs, and (2) the performance indicator is introduced as an evaluation metric of product configuration plans. A case study on product improvement was carried out for the interior space of automotive, to validate the feasibility and advantages of the proposed method. This proposed NA-IPA model provides designers with an efficient method to improve product design and customer satisfaction in response to market competition.
The growth of the higher education population and different school paths to access an academic degree has increased the heterogeneity of students inside the classroom. Consequently, the effectiveness ...of traditional teaching methods has reduced. This paper describes the design, development, implementation and evaluation of a tutoring system (TS) to improve student's engagement in higher mathematics. The TS design was based on the Personalized System of Instruction of the Mastery Learning pedagogical approach and can be implemented in any higher education course with mathematics needs. The TS consists on small self‐paced modularized units of educational contents, including tutorial videos, notes and formative e‐assessment with personalized feedback. The TS ensures that the student is only allowed to proceed to the next unit after he or she achieves the required mastery criterion of the current unit. The TS was implemented in the Quantitative Methods course of an undergraduate degree and received good acceptance from students. It was also recognized that TS contributed to learning and engagement with the discipline. Through an experimental research experience, it has been shown that the imposition of restrictions on the advance to the next level by a mastery criterion leads to a significant improvement in student's engagement and performance.
Lay Description
What is already known about this topic?
The Information and Communication Technologies have a great potential for any individualized math teaching program.
There are advantages of the implementation of the Personalized System of Instruction pedagogy in higher mathematics.
The tutorial systems may improve student's engagement and performance.
The transcription of paper‐based mathematics examinations into an electronic format is feasible for a significant proportion of the questions as currently assessed.
What this paper adds:
The use of an online tutorial system with design based on the Personalized System of Instruction leads to a significant improvement in student's engagement and performance.
Using e‐assessments with formative feedback is feasible as self‐assessment tool.
The positive effects in student's engagement and performance are boosted by the imposition of mandatory mastery criteria on the advance to the next level.
Implications for practice and/?or policy:
Efforts should be made to make the tutorial systems of mathematics more attractive.
The implementation of online exercises in which the number of fields is defined by the student may provide an important improvement in the interaction for some types of questions.
Performance analysis has become a vital technique for managing airport practices. However, most DEA models applied to airports assume that inputs and outputs are known with absolute precision. Here, ...we use Fuzzy-DEA models to capture vagueness in input and output measurements obtained from Nigerian airports. These results are subsequently treated by bootstrapped truncated regressions to control the random effects inherent to any sample. Results indicate that the joint use of bootstrapped regressions and FDEA models leads to more robust results, in the sense that fewer significant contextual variables are identified as efficiency drivers. When controlling for fuzziness and randomness, capacity cost was found to be the only significant variable, in addition to a learning component represented by trend. Policy design for Nigerian airports should focus simultaneously on third-party capacity management – such as privatization - while fostering continuous improvement practices to sustain the learning curve.
•FDEA is used to assess uncertainty in I/O measures obtained from Nigerian airports.•Fuzzy efficiencies are used in bootstrap regressions to find relevant context variables.•Results show that fuzziness should also be controlled altogether with randomness.•Capacity cost was found to be the only significant variable.•A learning component represented by trend was also found in Nigerian airports.
Disorder, which qualitatively describes some measure of irregularities in spatial patterns, is ubiquitous in many-body systems, equilibrium and non-equilibrium states of matter, network structures, ...biological systems and wave–matter interactions. In photonics, the introduction of order and disorder for device applications has traditionally been treated separately. However, recent developments in nanofabrication and design strategies have enabled the use of materials that lie between the extremes of order and disorder that can yield innovative optical phenomena owing to their engineered disordered patterns. Here, we review recent achievements in the emerging field of engineered disorder in photonics by outlining milestones in the control of the spectrum, transport, wavefront and topology of light in disordered structures. We show that engineered disorder has begun to transform the traditional landscape of photonics by introducing a greatly enhanced design freedom and, hence, has great potential for the rational design of the next generation of materials.In photonics, the introduction of order and disorder has traditionally been treated separately. However, recent developments in nanofabrication and design strategies have enabled the use of materials that lie between the extremes of order and disorder that can yield innovative optical phenomena. This Review surveys the basics and recent achievements of engineered disorder in photonics.
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