Active fixturing: literature review and future research directions

Fixtures are used to fixate, position and support workpieces and represent a crucial tool in manufacturing. Their performance determines the result of the whole manufacturing process of a product. There is a vast amount of research done on automatic fixture layout synthesis and optimisation and fixture design verification. Most of this work considers fixture mechanics to be static and the fixture elements to be passive. However, a new generation of fixtures has emerged that has actuated fixture elements for active control of the part–fixture system during manufacturing operations to increase the end product quality. This paper analyses the latest studies in the field of active fixture design and its relationship with flexible and reconfigurable fixturing systems. First, a brief introduction is given on the importance of research of fixturing systems. Secondly, the basics of workholding and fixture design are visited, after which the state-of-the-art in active fixturing and related concepts is presented. Fourthly, part–fixture dynamics and design strategies which take these into account are discussed. Fifthly, the control strategies used in active fixturing systems are examined. Finally, some final conclusions and prospective future research directions are presented

Extraction of pure components from overlapped signals in gas chromatography-mass spectrometry (GC-MS)

Gas chromatography-mass spectrometry (GC-MS) is a widely used analytical technique for the identification and quantification of trace chemicals in complex mixtures. When complex samples are analyzed by GC-MS it is common to observe co-elution of two or more components, resulting in an overlap of signal peaks observed in the total ion chromatogram. In such situations manual signal analysis is often the most reliable means for the extraction of pure component signals; however, a systematic manual analysis over a number of samples is both tedious and prone to error. In the past 30 years a number of computational approaches were proposed to assist in the process of the extraction of pure signals from co-eluting GC-MS components. This includes empirical methods, comparison with library spectra, eigenvalue analysis, regression and others. However, to date no approach has been recognized as best, nor accepted as standard. This situation hampers general GC-MS capabilities, and in particular has implications for the development of robust, high-throughput GC-MS analytical protocols required in metabolic profiling and biomarker discovery. Here we first discuss the nature of GC-MS data, and then review some of the approaches proposed for the extraction of pure signals from co-eluting components. We summarize and classify different approaches to this problem, and examine why so many approaches proposed in the past have failed to live up to their full promise. Finally, we give some thoughts on the future developments in this field, and suggest that the progress in general computing capabilities attained in the past two decades has opened new horizons for tackling this important problem

Impact of Systemic Inflammation and Autoimmune Diseases on apoA-I and HDL Plasma Levels and Functions

The cholesterol of high-density lipoproteins (HDLs) and its major proteic component, apoA-I, have been widely investigated as potential predictors of acute cardiovascular (CV) events. In particular, HDL cholesterol levels were shown to be inversely and independently associated with the risk of acute CV diseases in different patient populations, including autoimmune and chronic inflammatory disorders. Some relevant and direct anti-inflammatory activities of HDL have been also recently identified targeting both immune and vascular cell subsets. These studies recently highlighted the improvement of HDL function (instead of circulating levels) as a promising treatment strategy to reduce inflammation and associated CV risk in several diseases, such as systemic lupus erythematosus and rheumatoid arthritis. In these diseases, anti-inflammatory treatments targeting HDL function might improve both disease activity and CV risk. In this narrative review, we will focus on the pathophysiological relevance of HDL and apoA-I levels/functions in different acute and chronic inflammatory pathophysiological conditions

Ethics and biodiversity offsetting

Biodiversity offsetting is an increasingly applied tool aiming to compensate for environmental damage caused by exploitation projects. Critics, however, raise concerns over the purported effectiveness of offsetting and question the ethical underpinnings and implications of offsetting. These ethical dimensions have largely been overlooked in research, which may lead to offsetting systems that fail to respect the values intended to be safeguarded. To address these dimensions, 5 ethical objections in the scientific literature were identified: offsetting violates nature's intrinsic value; losses of nature cannot be compensated for by human interventions; too little is known to make adequate trades; offsetting impedes virtuous dispositions toward nature; and offsetting has negative justice implications. We examined these objections and arguments against them based on the ethical concepts of intrinsic and instrumental values, anthropocentrism, nonanthropocentrism, and deontological, consequentialist, and virtue-ethical paradigms. Both nonanthropocentric and anthropocentric concerns were expressed in deontological, consequential, and virtue-ethical framings. Objections mostly had a deontological or virtue-ethical basis, whereas counterarguments were based on consequential reasoning, but common ground in practice is often conceivable. Based on our findings, we formulated 10 recommendations for policy makers and 5 questions for practitioners to consider. We propose, for example, that policy makers clarify aims, legislate on no-go areas, and govern the use of multipliers. We suggest that practitioners consider, for instance, how to improve case-specific knowledge and promote learning and stakeholder engagement. We hope these recommendations and questions will encourage further discussion of the ethics of biodiversity offsets and ultimately strengthen the respect for biodiversity and human-welfare values at stake in offsetting projects.生物多样性补偿旨在补偿开发项目造成的环境破坏, 正日益得到应用。然而, 有批评者对补偿的有效性提出了担忧, 并对其道德基础和作用提出了质疑。以往研究很大程度忽视了这些伦理维度, 这可能导致生物多样性补偿系统没有尊重其旨在维护的价值。为了解决这些问题, 我们通过科学文献综述确定了五项伦理上的反对意见: 补偿机制违背了自然的内在价值; 人类干预不能补偿自然的损失; 人们所知甚少, 无法进行适当的交易补偿; 补偿损害了对自然的善意; 补偿会带来负面的影响。我们基于内在价值和工具价值的伦理概念、人类中心主义、非人类中心主义、道义论、结果论和美德 - 伦理范式, 检验了这些反对意见和对其的争论。非人类中心主义和人类中心主义的关注点都在道义论、结果论和美德 - 伦理框架中得到了表达。反对意见大多有道义论或美德 - 伦理基础, 而对它们的回应则基于结果论推理, 但通常在实践中双方存在可能的共同基础。基于我们的研究发现, 我们向政策制定者提出了 10 条建议, 并对实践者提出了 5 个问题供其考虑。例如, 我们建议决策者明确目标, 立法确定禁区, 管理乘数的使用。我们还建议实践者思考如何积累具体案例的知识、促进学习和推动利益相关者参与。我们希望这些建议和问题将鼓励人们进一步讨论生物多样性补偿的伦理问题, 并最终加强在补偿项目中对生物多样性和人类福利价值的尊重。【翻译: 胡怡思; 审校: 聂永刚】La compensación de la biodiversidad es una herramienta que cada vez se aplica más a la búsqueda de la remuneración por el daño ambiental causado por proyectos de explotación. Sin embargo, hay quienes la critican basándose en la presunta efectividad de las compensaciones y cuestionan los sustentos éticos y las implicaciones de las compensaciones. Estas dimensiones éticas han sido ignoradas en la investigación, lo cual puede resultar en sistemas que no respetan los valores que se pretende salvaguardar. Para resolver estas dimensiones identificamos cinco objeciones éticas en la literatura: las compensaciones violan el valor intrínseco de la naturaleza; las pérdidas de la naturaleza no pueden compensarse mediante intervenciones humanas; se conoce muy poco para realizar intercambios adecuados; las compensaciones impiden las disposiciones virtuosas hacia la naturaleza; y las compensaciones tienen implicaciones de justicia negativa. Analizamos estas objeciones y los argumentos en su contra basados en los conceptos éticos de los valores intrínsecos e instrumentales, el antropocentrismo, el no antropocentrismo y los paradigmas deontológico, consecuencialista y de virtud ética. Tanto las preocupaciones antropocéntricas como las no antropocéntricas se expresaron mediante encuadres deontológicos, consecuencialistas y de virtud ética. Las objeciones principalmente tuvieron una base deontológica o de virtud ética, mientras que los contraargumentos estuvieron basados en el razonamiento consecuencial pero los puntos de coincidencia en la práctica con frecuencia son concebibles. Con base en nuestros hallazgos formulamos diez recomendaciones para los formuladores de políticas y cinco preguntas para los practicantes de la conservación para que las tomen a consideración. Por ejemplo, proponemos que los formuladores de políticas clarifiquen los objetivos, legislen las áreas prohibidas y determinen el uso de multiplicadores. Sugerimos que los practicantes consideren cómo mejorar el conocimiento específico por caso y promover el aprendizaje y la participación de los actores sociales. Esperamos que estas recomendaciones y preguntas fomenten una mayor discusión sobre la ética de las compensaciones de biodiversidad y, finalmente, fortalezcan el respeto por la biodiversidad y los valores de bienestar humano en juego en los proyectos de compensaciones