536 research outputs found
Toward resilient product-based service supply chains
Circular economies represent a step toward breaking the linear production model in supply chains. As drivers of enhanced circularity, product-based service (PBS) offerings extend and/or intensify the utilization period of products and thus decelerate the flow of resources. As a result, transitions to PBSs can yield outstanding, sustainable commercial benefits, including minimized resource input into production and the reduction of waste, all without jeopardizing growth. At the same time, PBS settings are highly servitized, entail different flows of people and knowledge, and engender new uncertainties, especially regarding product lifetime and product quality. Although a new way of handling such variation in PBS supply chains involves optimizing logistical tradeoffs, PBS supply chains are subject to uncertainties not only during normal market situations but also during volatile situations, including the COVID-19 pandemic. This thesis is based on research that followed a qualitative approach using abductive reasoning. Compiling three papers drawing from three studies conducted across several manufacturing industries, the thesis outlines the relationship between circularity and resilience and provides guidance toward realizing resilient PBS supply chains. Study 1 investigated logistical tradeoffs that support enhanced circularity in PBS supply chains, whereas Study 2 probed disruptions and responses in PBS supply chains following a major external event. Last, Study 3 examined the intersection between resilience and sustainability in manufacturing supply chains. The results of those studies in light of findings in the literature underscore three major findings. First, PBS supply chains have to be understood from a wider perspective on logistical tradeoffs (i.e., material versus people, people versus knowledge, and knowledge versus information) added to the traditional logistical tradeoff between material and information in product-based supply chains. Second, the intersection between circularity and resilience showcases the capacity of those logistical tradeoffs to respond to disruptions and thus cultivate resilience in PBS supply chains. That finding highlights the importance of improved local knowledge that is as close to consumers as possible. Third, the thesis provides a framework of three building blocks for developing resilience in PBS supply chains: (i) developing adaptive resilience, related to Mode I of resilience, to alter normal service offering or delivery; (ii) developing transformative resilience, related to Modes 2 and 3, meaning the notion of extending or radically changing the service offering or delivery; and (iii) integrating those dimensions of resilience with sustainability
Enhanced circularity in aftermarkets: logistics tradeoffs
Purpose: The purpose of this paper is to identify requirements and tradeoffs on logistics services for enhanced circularity of materials and resources. Design/methodology/approach: Based on multiple case study design and abductive reasoning, the study investigates 13 different product categories. The data were analyzed based on theoretical, a priori codes from the literature review. Inductive, emerging codes were added to the coding scheme during the analysis. Findings: Requirements of logistics services to support slowing of resource flows are categorized with respect to initiator, location of the service, single or multiple actors, and transportation of parts, products and people. Moreover, the study identifies new logistics tradeoffs: material and people, knowledge and people, and information and knowledge. Transportation of product, people and parts can be reduced by increasing local knowledge and improve information sharing. Research limitations/implications: This review contributes to the understanding of the relationship between logistics services and enhancement of circularity by highlighting requirements on logistics services in the aftermarket supply chain that support slowing of resource flows. To enhance circularity, logistics services must extend the traditional material information flow with the flow of people and knowledge, respectively. Practical implications: The categorization provides practitioners and researchers with an overview of requirements and tradeoffs on logistics services to enhance circularity of a particular circular cycle. The implications will provide an opportunity to address environmental impact of transportation and improve the utilization of scarce materials. Social implications: Variety of tradeoffs in logistics services can enhance slowing and hence circularity of scarce materials. Originality/value: First, the authors illustrate how traditional tradeoffs in logistics such as flow of materials, resources and people need to be addressed to enhance circularity through slowing. Second, the authors identify two new tradeoffs in logistics services: knowledge flow and degree of customer involvement
Coherent anti-Stokes Raman scattering microscopy of human smooth muscle cells in bioengineered tissue scaffolds
The integration of living, human smooth muscle cells in biosynthesized cellulose scaffolds was monitored by nonlinear microscopy toward contractile artificial blood vessels. Combined coherent anti-Stokes Raman scattering (CARS) and second harmonic generation (SHG) microscopy was applied for studies of the cell interaction with the biopolymer network. CARS microscopy probing CH(2)-groups at 2845 cm(-1) permitted three-dimensional imaging of the cells with high contrast for lipid-rich intracellular structures. SHG microscopy visualized the fibers of the cellulose scaffold, together with a small signal obtained from the cytoplasmic myosin of the muscle cells. From the overlay images we conclude a close interaction between cells and cellulose fibers. We followed the cell migration into the three-dimensional structure, illustrating that while the cells submerge into the scaffold they extrude filopodia on top of the surface. A comparison between compact and porous scaffolds reveals a migration depth of <10 μm for the former, whereas the porous type shows cells further submerged into the cellulose. Thus, the scaffold architecture determines the degree of cell integration. We conclude that the unique ability of nonlinear microscopy to visualize the three-dimensional composition of living, soft matter makes it an ideal instrument within tissue engineering
A GH115 alpha-glucuronidase from Schizophyllum commune contributes to the synergistic enzymatic deconstruction of softwood glucuronoarabinoxylan
Background: Lignocellulosic biomass from softwood represents a valuable resource for the production of biofuels and bio-based materials as alternatives to traditional pulp and paper products. Hemicelluloses constitute an extremely heterogeneous fraction of the plant cell wall, as their molecular structures involve multiple monosaccharide components, glycosidic linkages, and decoration patterns. The complete enzymatic hydrolysis of wood hemicelluloses into monosaccharides is therefore a complex biochemical process that requires the activities of multiple degradative enzymes with complementary activities tailored to the structural features of a particular substrate. Glucuronoarabinoxylan (GAX) is a major hemicellulose component in softwood, and its structural complexity requires more enzyme specificities to achieve complete hydrolysis compared to glucuronoxylans from hardwood and arabinoxylans from grasses. Results: We report the characterisation of a recombinant α-glucuronidase (Agu115) from Schizophyllum commune capable of removing (4-O-methyl)-glucuronic acid ((Me)GlcA) residues from polymeric and oligomeric xylan. The enzyme is required for the complete deconstruction of spruce glucuronoarabinoxylan (GAX) and acts synergistically with other xylan-degrading enzymes, specifically a xylanase (Xyn10C), an α-l-arabinofuranosidase (AbfA), and a β-xylosidase (XynB). Each enzyme in this mixture showed varying degrees of potentiation by the other activities, likely due to increased physical access to their respective target monosaccharides. The exo-acting Agu115 and AbfA were unable to remove all of their respective target side chain decorations from GAX, but their specific activity was significantly boosted by the addition of the endo-Xyn10C xylanase. We demonstrate that the proposed enzymatic cocktail (Agu115 with AbfA, Xyn10C and XynB) achieved almost complete conversion of GAX to arabinofuranose (Araf), xylopyranose (Xylp), and MeGlcA monosaccharides. Addition of Agu115 to the enzymatic cocktail contributes specifically to 25 % of the conversion. However, traces of residual oligosaccharides resistant to this combination of enzymes were still present after deconstruction, due to steric hindrances to enzyme access to the substrate. Conclusions: Our GH115 α-glucuronidase is capable of finely tailoring the molecular structure of softwood GAX, and contributes to the almost complete saccharification of GAX in synergy with other exo- and endo-xylan-acting enzymes. This has great relevance for the cost-efficient production of biofuels from softwood lignocellulose.Lauren S. McKee, Hampus Sunner, George E. Anasontzis, Guillermo Toriz, Paul Gatenholm, Vincent Bulone, Francisco Vilaplana and Lisbeth Olsso
Effect of cultivation conditions on the structure and morphological properties of BNC biomaterials with a focus on vascular grafts
20 New materials that are not thrombogenic and have mechanical properties that mimic the native blood vessel are in very great demand. Nanocellulose produced by the bacteria Gluconacetobacter xylinus is a biomaterial that has gained interest in the field of tissue engineering because of its unique properties, such as great mechanical strength, high water content (around 99%), and the ability to be shaped into three-dimensional structures during biosynthesis. The fabrication process of bacterial nanocellulose (BNC) vascular grafts is very unique because the material synthesis and product formation takes place simultaneously. The bio mechanical performance, which includes rupture pressure and compliance along with biological response (endothelialization, blood compatibility, etc.), is dependent on the morphology of a fibrillar network. The network formation is affected by cellulose assembly and bacteria motion, proliferation rate, and other factors. An understanding of the effects of cultivation conditions on BNC network formation is therefore of great importance
Aplicação de BI no processo de recuperação de credito: um estudo de caso.
Este trabalho apresenta um estudo de caso de aplicação da tecnologia de Business Inteligence - BI em conjunto com o processo de planejamento estratégico de modo a proporcionar melhorias em processos operacionais e por sua vez ganhos financeiros. O trabalho baseou-se na aplicação de ferramentas de BI e algoritmos de processamento analÃtico em uma empresa que atua no mercado de cobrança. A análise do estudo de caso concentra-se em demonstrar os resultados operacionais e financeiros mais eficientes no que tange à cobrança de carteiras de clientes selecionados para os experimentos possibilitando o alcance de objetivos e metas organizacionai
Design and biofabrication of a leaf-inspired vascularized cell-delivery device
We designed and biofabricated a channeled construct as a possible cell-delivery device that can be endothelialized to overcome size limitations due to oxygen diffusion. The channeled device mimicking a leaf was designed using computer-aided design software, with fluid flow through the channels visualized using simulation studies. The device was fabricated either by form casting using a custom 3D-printed plastic mold or by 3D-bioprinting using Pluronic F-127 as sacrificial ink to print the channels. The actual leaf was cast or bioprinted using hydrogel made from a mixture of tunicate cellulose nanofibers and alginate that was cross-linked in calcium chloride solution to allow a stable device. The resulting device was a 20
7 8
7 3 mm or 35
7 18
7 3 mm (length
7 width
7 height) leaf with one main channel connected to several side channels. Surface modification using periodate oxidation, followed by laminin bioconjugation, was performed to enhance endothelial cell adhesion in the channels. We subsequently used human umbilical vein endothelial cells to demonstrate the efficacy of the device for promoting endothelialization. These results indicated that the biofabricated device has great potential for use in tissue-engineering for various applications associated with the need of perfusable vasculature
Biomaterial and biocompatibility evaluation of tunicate nanocellulose for tissue engineering
Extracellular matrix fibril components, such as collagen, are crucial for the structural properties of several tissues and organs. Tunicate-derived cellulose nanofibrils (TNC) combined with living cells could become the next gold standard for cartilage and soft-tissue repair, as TNC fibrils present similar dimensions to collagen, feasible industrial production, and chemically straightforward and cost-efficient extraction procedures. In this study, we characterized the physical properties of TNC derived from aquaculture production in Norwegian fjords and evaluated its biocompatibility regarding induction of an inflammatory response and foreign-body reactions in a Wistar rat model. Additionally, histologic and immunohistochemical analyses were performed for comparison with expanded polytetrafluoroethylene (ePTFE) as a control. The average length of the TNC as determined by atomic force microscopy was tunable from 3 mu m to 2.4 mu m via selection of a various number of passages through a microfluidizer, and rheologic analysis showed that the TNC hydrogels were highly shear-thinning and with a viscosity dependent on fibril length and concentration. As a bioink, TNC exhibited excellent rheological and printability properties, with constructs capable of being printed with high resolution and fidelity. We found that post-print cross-linking with alginate stabilized the construct shape and texture, which increased its ease of handling during surgery. Moreover, after 30 days in vivo, the constructs showed a highly-preserved shape and fidelity of the grid holes, with these characteristics preserved after 90 days and with no signs of necrosis, infection, acute inflammation, invasion of neutrophil granulocytes, or extensive fibrosis. Furthermore, we observed a moderate foreign-body reaction involving macrophages, lymphocytes, and giant cells in both the TNC constructs and PTFE controls, although TNC was considered a nonirritant biomaterial according to ISO 10993-6 as compared with ePTFE. These findings represent a milestone for future clinical application of TNC scaffolds for tissue repair. One sentence summary: In this study, the mechanical properties of tunicate nanocellulose are superior to nanocellulose extracted from other sources, and the biocompatibility is comparable to that of ePTFE
Long-term in vivo survival of 3D-bioprinted human lipoaspirate-derived adipose tissue: proteomic signature and cellular content
Three-dimensional (3D)-bioprinted lipoaspirate-derived adipose tissue (LAT) is a potential alternative to lipo-injection for correcting soft-tissue defects. This study investigated the long-term in vivo survival of 3D-bioprinted LAT and its proteomic signature and cellular composition. We performed proteomic and multicolour flow cytometric analyses on the lipoaspirate and 3D-bioprinted LAT constructs were transplanted into nude mice, followed by explantation after up to 150\ua0days. LAT contained adipose-tissue-derived stem cells (ASCs), pericytes, endothelial progenitor cells (EPCs) and endothelial cells. Proteomic analysis identified 6,067 proteins, including pericyte markers, adipokines, ASC secretome proteins, proangiogenic proteins and proteins involved in adipocyte differentiation and developmental morphogenic signalling, as well as proteins not previously described in human subcutaneous fat. 3D-bioprinted LAT survived for 150\ua0days in vivo with preservation of the construct shape and size. Furthermore, we identified human blood vessels after 30 and 150\ua0days in vivo, indicating angiogenesis from capillaries. These results showed that LAT has a favourable proteomic signature, contains ASCs, EPCs and blood vessels that survive 3D bioprinting and can potentially facilitate angiogenesis and successful autologous fat grafting in soft-tissue reconstruction
Alginate and tunicate nanocellulose composite microbeads – Preparation, characterization and cell encapsulation
Alginate has been used for decades for cell encapsulation. Cellulose nanofibrils (CNF) from tunicates are desirable in biomedicine due to high molecular weight, purity, crystallinity, and sustainable production. We prepared microbeads of 400–600 μm of alginate and tunicate CNF. Greater size, dispersity and aspect ratio were observed in microbeads with higher fractions of CNF. CNF content in Ca-crosslinked alginate microbeads decreased stability upon saline exposure, whereas crosslinking with calcium (50 mM) and barium (1 mM) yielded stable microbeads. The Young's moduli of gel cylinders decreased when exchanging alginate with CNF, and slightly increased permeability to dextran was observed in microbeads containing CNF. Encapsulation of MC3T3 cells revealed high cell viability after encapsulation (83.6 ± 0.4%) in beads of alginate and CNF. NHDFs showed lower viability but optimizing mixing and production techniques of microbeads increased cell viability (from 66.2 ± 5.3% to 72.7 ± 7.5%).publishedVersio
- …