1,720,957 research outputs found
Poly(lactic acid)-Based Electrospun Fibrous Structures for Biomedical Applications
Full text linkPoly(lactic acid)(PLA) is an aliphatic polyester that can be derived from natural and renewable resources. Owing to favorable features, such as biocompatibility, biodegradability, good thermal and mechanical performance, and processability, PLA has been considered as one of the most promising biopolymers for biomedical applications. Particularly, electrospun PLA nanofibers with distinguishing characteristics, such as similarity to the extracellular matrix, large specific surface area and high porosity with small pore size and tunable mechanical properties for diverse applications, have recently given rise to advanced spillovers in the medical area. A variety of PLA-based nanofibrous structures have been explored for biomedical purposes, such as wound dressing, drug delivery systems, and tissue engineering scaffolds. This review highlights the recent advances in electrospinning of PLA-based structures for biomedical applications. It also gives a comprehensive discussion about the promising approaches suggested for optimizing the electrospun PLA nanofibrous structures towards the design of specific medical devices with appropriate physical, mechanical and biological functions
Application of Cellulose-Based Materials as Water Purification Filters; A State-of-the-Art Review
No full textWater scarcity, identified as the most serious global risk by the World Economic Forum, poses significant challenges due to its potential impact over the next decade. This study focuses on addressing the pressing issues of water scarcity and water quality through the use of cellulose-based materials for manufacturing water filters. Industrial wastewater containing dyes and heavy metal ions is a major contributor to water pollution, affecting underground water sources. Copper, mercury, chromium, lead, and tin are among the most common and environmentally damaging heavy metal ions due to their high toxicity, low biodegradability, and persistence in the food chain. Water purification processes are crucial for ensuring safe consumption. Bio-compatible and renewable materials have gained attention for water treatment applications in recent years. Cellulose-based materials, such as cellulose nanofibers (CNFs) and cellulose nanocrystals (CNCs), possess unique characteristics including biodegradability, suitable aspect ratio, thermal stability, high strength, stiffness, renewability, and accessibility. This research aims to review the utilization of cellulose-based materials, particularly modified CNC and CNF aerogels, for manufacturing water filters. These materials exhibit high porosity, large specific surface area, and functional groups on their surfaces, making them promising adsorbents for removing water pollutants such as heavy metals, organic dyes, pharmaceutical waste, and oils. Our study demonstrates that modified CNFs and CNCs have shown an exceptional absorption capacity of approximately 98% for heavy metals. By focusing on the specific application of cellulose-based materials for water filtration, this research contributes to the development of effective and sustainable solutions for water purification, addressing the critical challenges posed by water scarcity and pollution
Manufacturing of Fluff Pulp Using Different Pulp Sources and Bentonite on an Industrial Scale for Absorbent Hygienic Products
Full text linkIn this study, for the first time, a composite fluff pulp was produced based on the combination of softwood (i.e., long-length fiber), hardwood (i.e., short-length fiber), non-wooden pulps (i.e., bagasse) and bentonite, with specific amounts to be used in hygienic pads (e.g., baby diapers and sanitary napkins). After the defibration process, the manufactured fluff pulp was placed as an absorbent mass in diapers and sanitary napkins. Therefore, tests related to the fluff pulp, such as grammage, thickness, density, ash content, humidity percentage, pH and brightness, tests related to the manufactured baby diapers, such as absorption capacity, retention rate, retention capacity, absorption time and rewet, and tests related to the sanitary napkin, such as absorption capacity and rewet, were performed according to the related standards. The results demonstrated that increasing the amount of bagasse pulp led to increasing the ash content, pH and density of fluff pulp and decreasing the brightness. The addition of bentonite as a filler also increased ash content and pH of fluff pulp. The results also demonstrated that increasing of bagasse pulp up to 30% in combination with softwood pulp led to increasing absorption capacity, retention rate, retention capacity, absorption time and rewet of baby diapers and of sanitary napkins
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Variations on the Author
Full text link“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
Full text linkWe 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
Development and Characterization of Sodium Alginate-Based Bio-hybrid Super Absorbent Polymer with High Retention Capacity Suitable for Baby Diapers
No full textDue to their capacity of water absorption, super absorbent polymers (SAPs) are greatly requested in hygienic applications, thus representing large volume products needing for a good biodegradability. This study aims to develop new SAPs for baby diapers by combining sodium alginate (SA) and cellulose nanocrystals (CNC) with acrylic acid (AA). The effect of different AA/SA ratios and CNC concentrations in the presence of ammonium persulfate (APS) as an initiator, and N–N-methylene bis-acrylamide (NMBA) as a cross-linker is investigated. We assess morphological and physicochemical properties of the SAPs, as well as their absorption characteristics and rheological properties. The results show that SAPs with AA/SA weight ratio of 70:30 containing 2% w/w CNC have the highest water absorption capacity, i.e., 78.4 g/g in saline solution. These SAPs also demonstrate high retention capacity and better absorption capacity under load than other SAPs. We further optimize the formulation by increasing the neutralization degree of AA and reducing the solid content, reaching an absorption capacity in the salt solution up to 100.08 g/g. Finally, the absorbent core made with fewer amounts of SAPs and fluff pulp led to functional properties superior to those of commercial baby diapers. High polysaccharide content SAPs could contribute to improve diaper sustainability
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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