1,724,208 research outputs found
Low‐Temperature PureB CVD Technology for CMOS Compatible Photodetectors
No full textIn this chapter, a new technology for low‐temperature (LT, 400°C) boron deposition is developed, which provides a smooth, uniform, closed LT boron layer. This technology is successfully employed to create near‐ideal LT PureB (pure boron) diodes with low, deep junction‐like saturation currents, allowing full integration of LT PureB photodiodes with electronic interface circuits and other sensors on a single chip. In this way, smart‐sensor systems or even charge‐coupled device (CCD) or complementary metal oxide semiconductor (CMOS) ultraviolet (UV) imagers can be realised
Tackling Nanoplastics in Aquatic Environments: Developing Valuable Reference Standards for Real-Time Detection and Remediation
No full textThe widespread use of petroleum-based plastic products has profoundly shaped modern life, introducing an era of "throwaway living" defined by convenience and disposability. However, the persistent nature of plastic waste has evolved into a critical environmental issue, with plastic debris accumulating across terrestrial, aquatic, and atmospheric ecosystems at alarming rates. Research has revealed that plastics degrade into smaller particles, including microplastics (MPs) (5 mm–1 μm) and nanoplastics (NPs) (<1 μm), which are now detected in oceans, farmlands, mountains, food, beverages, and even living organisms, creating new types of environmental pollutants.
In response to environmental challenges caused by petroleum-based plastic pollution, society is increasingly adopting bio-based plastics derived from renewable sources. Poly(lactic acid) (PLA) is considered the most widely used bioplastic in real-life applications due to its thermoformability, low cost, and industrial compostability. However, if discarded, PLA does not fully degrade under natural environmental conditions and follows a similar pathway of conventional plastics, breaking down into MPs and NPs. This underscores the need to study the environmental fate and risks of such types of bio-based plastic alongside traditional plastics.
Despite growing awareness of plastic pollution, current research on NPs remains limited mainly to conventional plastics, with several critical challenges hampering progress. These include the lack of environmentally relevant reference materials, especially for bio-based plastics leading to inaccurate representations of plastic types, and the absence of standardized methodologies, complicating cross-study comparisons. Analytical limitations further restrict the detection of smaller particles (<1 μm) at low concentrations. At the same time, the complex interactions between NPs and environmental matrices alter particle behavior, complicating their detection, characterization, and remediation. Addressing these challenges is essential to understanding and managing plastic pollution, particularly for bio-based plastics like PLA.
This thesis focuses on tackling these pressing issues by developing integrated approaches to address the challenges of lack of reference materials, remediation, and detection of NPs. The work introduces a protocol for fabricating bio-based PLA NPs using the laser ablation method. This technique produces particles with properties like those anticipated in aquatic environments, providing a valuable reference model for studying environmental fate, ecological interactions, and remediation strategies. Subsequently, innovative approaches for remediating these environmentally relevant NPs in water using piezo-photocatalytic systems are explored, offering practical solutions for NP degradation in water without the requirement of high energy sources but just solar light irradiation and wave movements. The final section investigates advanced detection technologies, specifically Electrolyte-Gated Carbon Nanotube Field-Effect Transistor (EG-CNT-FET) sensors, demonstrating their ability to detect NPs, even with surface modifications, in complex environmental samples.
This thesis emphasizes the critical importance of addressing the environmental impact of NPs through integrated strategies, combining realistic modeling, effective remediation, and advanced detection technologies. By focusing on bio-based plastics like PLA, this work provides a comprehensive framework for mitigating the environmental risks of plastic pollution and supporting the development of sustainable solutions for future challenges
Development of Poly(lactic acid) nanoplastics and studies on their fate in the environment
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Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Predicting Outcome after Acute Severe Ulcerative Colitis: A Contemporary Review and Areas for Future Research
No full textAcute Severe Ulcerative Colitis (ASUC) is a severe form of ulcerative colitis relapse which requires hospitalization and intensive medical intervention to avoid colectomy. The timely recognition of patients at risk of corticosteroid failure and the early initiation of medical rescue therapy are paramount in the management of ASUC. The choice of medical rescue therapy is influenced by multiple factors, especially patient’s prior treatment history. This decision should involve the patient and ideally a multidisciplinary team of healthcare professionals, including gastroenterologists, radiologists, surgeons and enterostomal therapists. Although several predictive models have been developed to predict corticosteroid failure in ASUC, there is no single validated tool that is universally utilized. At present, infliximab and cyclosporine are the only agents systematically evaluated and recommended for medical rescue therapy, with recent reports of off-label utilization of tofacitinib and upadacitinib in small case series. The available evidence regarding the efficacy and safety of these oral small molecules for ASUC is insufficient to provide definitive recommendations. Early decision-making to assess the response to medical rescue therapy is essential, and the decision to pursue surgery in the case of treatment failure should not be delayed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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