511 research outputs found
Recombinant gelatin and collagen from methylotrophic yeasts
No full textBased on its structural role and compatibility within the human body, collagen is a commonly used biomaterial in medical applications, such as cosmetic surgery, wound treatment and tissue engineering. Gelatin is in essence denatured and partly degraded collagen and is, as a result of its unique functional and chemical properties, also used in many medical and pharmaceutical products. Collagen and gelatin are traditionally extracted from animal tissues. The quality and the characteristics of the proteins are not very reproducible in today's batch-to-batch production processes and recently, potential contamination of collagen and gelatin with viruses and prions (causing BSE) became a matter of concern. BSE is thought to cause a new variety of the brain- wasting Creutzfeldt-Jacob disease in humans.Recombinant DNA technology may provide safe collagen and gelatins from which the quality and characteristics can precisely be controlled and reproduced and, in addition, opens up possibilities for novel functional "tailor-made" proteins.For the heterologous production of animal proteins yeasts are frequently used. Since yeasts are eukaryotes, most translational modification, needed for functionality and stability of recombinant animal proteins, normally occur. However prolyl 4-hydroxylation, essential for gelling properties of recombinant gelatin and thermal stability of recombinant collagen, is generally considered to be absent in yeast systems.In this study we explored the methylotrophic yeasts Hansenula polymorpha and Pichia pastoris for their use as recombinant production systems of natural and "tailor-made" gelatins and human collagen.We found that both yeasts are well able to cope with the repetitive gene sequences encoding animal gelatin and human collagen and showed that P. pastoris can produce synthetic gelatins with highly hydrophilic properties at high levels. Furthermore, it was discovered that H. polymorpha unexpectedly produced endogenous collagen-like proteins with 4-hydroxyproline amino acid residues. This finding indicated that the yeast H. polymorpha , in contract to what was generally believed, must contain intrinsic proly 4-hydroxyalse activity. Indeed, expression of murine gelatin in H. polymorpha yielded a secreted and hydroxylated product. We also investigated if H. polymorpha could be used for the production of recombinant human collagen. Intract human collagen trimers were obtained but they were not stable at temperatures higher than 15 °C, indicating that hydroxylation in the product was poor.In the course of this study we found putative prolyl 4-hydroxylase genes in different eukaryotic microbial systems. In the future these genes may be used to further develop yeasts into cell factories for the production of animal gelatins and thermally stable human collagen
Milnor’s Conjecture on Monotonicity of Topological Entropy: results and questions
No full text02.08.13 KB. Author has recieved permission from publisher to add the submitted version to Spiral.This note discusses Milnor’s conjecture on monotonicity of entropy and gives a short exposition of the ideas used in its proof which was obtained in joint work with Henk Bruin, see [BvS09]. At the end of this note we explore some related conjectures and questions
Instrumental and organizational aspects of a neutron activation analysis laboratory
No full textApplied Science
UvA-DARE (Digital Academic Repository) HUMU 780 A Single Ser259Arg Mutation in the Gene for Lipoprotein Lipase Causes Chylomicronemia in Moroccans of Berber Ancestry
No full textA single Ser 259Arg mutation in the gene for lipoprotein lipase causes chylomicronemia in Moroccans of Berber ancestry Foubert, L.; Bruin, T.; de Gennes, J.L.; Ehrenborg, E.; Furioli, J.; Kastelein, J.J.P.; Benlian, P.; Hayden, M.R. Published in: Human Mutation Link to publication Citation for published version (APA): Foubert, L., Bruin, T., de Gennes, J. L., Ehrenborg, E., Furioli, J., Kastelein, J. J. P., ... Hayden, M. R. (1997). A single Ser 259Arg mutation in the gene for lipoprotein lipase causes chylomicronemia in Moroccans of Berber ancestry. Human Mutation, 10, 179-185. General rights It is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons). Disclaimer/Complaints regulations If you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: https://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible
Op weg naar Schiphol: Studie naar de bereikbaarheid van mainpoort Schiphol
No full textDe nationale luchthaven Schiphol maakt een voor buitenstaanders onverwacht snelle groei door. De aan de groei gestelde (politieke) grenzen worden binnen afzienbare tijd bereikt, terwijl er een (nog) veel groter groeipotentieel ligt, met name omdat vliegen populairder lijkt dan ooit. Daarnaast is de grond op en rond de luchthaven zeer gewild bij projectontwikkelaars, alleen al gezien de zichtbare ruimtelijke expansie. Door het groeitempo van de luchthaven, maar ook van de regio waarvan zij deel uitmaakt, staat de ontsluitende infrastructuur onder zware druk. Toch wil de overheid dat Schiphol zich ontwikkelt tot een volwaardige mainport, om daarmee een goed vestigingsklimaat te realiseren, dat een grote aantrekkingskracht heeft op (multi)nationale bedrijven. Het versterken van de positie van de mainports Schiphol en de Rotterdamse haven wordt uitdrukkelijk genoemd als cruciaal instrument ter versterking van de internationale concurrentiepositie van Nederland. Dit is onder andere vertaald in de doelstelling om Schiphol in de top-5 van Europese luchthavens te houden. De gedachte die daaraan ten grondslag ligt, is dat een goed vestigingsklimaat bedrijven aantrekt en zo werkgelegenheid oplevert. Naast een gezond vestigingsklimaat is een ander belangrijk sturend aspect voor het worden van een mainport, een goede ontsluiting. Met andere woorden, Schiphol moet om mainport te kunnen zijn, een van de best bereikbare plekken van Nederland en misschien wel van Europa zijn. In deze studie wordt onderzocht hoe het gesteld is met de bereikbaarheid van Schiphol en wat het vergt aan weginfrastructuur, OVen (flankerend) beleid, om de bereikbaarheid van de luchthaven nu en in de toekomst te kunnen garanderen. Mainportontwikkeling... Wanneer we kijken naar grote mainport luchthavens in het buitenland, zoals de vliegvelden van Osaka, Chicago en Parijs, dan valt op dat deze behalve aan strikt luchthaven- en logistiek gebonden activiteiten, veel aandacht besteden aan het creëren van hoogwaardige kantoorlocaties en handelscentra. Daarnaast wordt ook veel aandacht besteed aan winkelgelegenheden, congrescentra, hotels en andere recreatieve voorzieningen. Ook op Schiphol is men ervan doordrongen dat een luchthaven met slechts core-business weinig overlevingskans heeft. Er wordt dan ook zowel door particulieren als door de overheid veel moeite gedaan om bedrijven te interesseren. De overheid steunt dus het idee om Schiphol tot mainport te ontwikkelen. Er moet dan echter wel een duidelijke visie zijn, op de toekomstige ruimtelijke structuur en de infrastructurele ondersteuning, om deze ontwikkeling vorm te kunnen geven. De inrichting en het infrastructurele skelet van het terrein hebben een soort kip-ei verhouding; ze zijn onlosmakelijk met elkaar verbonden. In samenhang met het aandragen van een verkeerskundige oplossing, moet een plan worden ontwikkeld voor de ruimtelijke indeling, waarbij zones worden aangegeven waarin een bepaalde activiteit plaats moet gaan vinden.Transport & PlanningCivil Engineering and Geoscience
Grijs en Groen, levensloopbestendige woningen in Beveren
No full textAfstudeerproject voor Architectuur en Bouwtechnologie. Onderzoek naar wat voor ouderen visueel comfort is en een toolbox met ruimtelijke middelen voor een architect om visueel comfortabele ruimte voor ouderen te ontwerpen. Ontwerp van levensloopbestendige woningen en een zorgsteunpunt in het Vlaamse dorp BeverenArchitectur
An ergonomic approach to the design of bicycle handlebar grips
No full textSummary This project is carried out in collaboration with bicycle accessories manufacturer Widek BV. Widek came with the plan to create a new design for bicycle handlebar grips with an increased ergonomic value compared to the currently available alternatives. The origination of this plan lies with the release of a paper containing new ergonomic knowledge on the pressure discomfort of the hand (di Brigida et al., 2021) and the realisation that the current situation around bicycle handlebar grips offers opportunities for improvement.This report describes the process of shaping the assignment, gathering information, creating a concept and concluding the completed project.IntroductionBecause this is not the usual way Widek approaches the development of a new product, they have left the initial assignment quite broad: ‘develop a new bicycle handlebar design with a focus on the ergonomics of the user’. To further define this assignment, explorative research is done to the client, their portfolio, production methods, clients, users and vision, and the context of bicycle handlebar grips in the current market. This allowed defining a scope for the project.ResearchThe research within this project consists of four different studies: (1) A literature study to the ergonomics of the human hand and wrist, (2) market research on the current and predicted context, (3) field work to gain insights into this context and (4) a survey among (potential) users to collect reasoning behind the found insights.DesignIn the design phase, a problem list is created containing all collected problems regarding the ergonomics of bicycle handlebar grips in the current context. This problem list is arranged based on importance and feasibility within this project and translated into a list of requirements and wishes that the concept must meet. Based on this, a focus area is defined within the original scope of the project: (1) pressure peaks on the hand and (2) incorrect wrist positions. Developing different solution directions resulted in three concepts of which physical prototypes are made. Using these prototypes, the concepts are assessed during user testing. This assessment, together with the research outcomes from this project, has led to the proposal of one of these concepts.ConcludingThis project is concluded with a preview of possible further development of the proposed concept by listing recommendations regarding the collected problems outside the scope focus area and additional research directions, found during concept creation.Integrated Product Desig
Emerg Infect Dis
No full textIn 2002, the National Legionella Outbreak Detection Program was implemented in the Netherlands to detect and eliminate potential sources of organisms that cause Legionnaires' disease (LD). During 2002-2012, a total of 1,991 patients with LD were reported, and 1,484 source investigations were performed. Of those sources investigated, 24.7% were positive for Legionella spp. For 266 patients with LD, 105 cluster locations were identified. A genotype match was made between a strain detected in 41 patients and a strain from a source location. Despite the systematic approach used by the program, most sources of LD infections during 2002-2012 remained undiscovered. Explorative studies are needed to identify yet undiscovered reservoirs and transmission routes for Legionella bacteria, and improved laboratory techniques are needed to detect Legionella spp. in clinical samples with a high background of microbial flora (such as soil)
Trendwatcher or trendsetter: 50 years of MTAA
No full textThe development on neutron activation analysis (NAA) into a technique of practical interest effectively started about 60 years ago, when nuclear reactors became available and widely accessible as intense sources of neutrons. During 50 out these 60 years, the series of Modern Trends in Activation Analysis (MTAA) Conferences acted as a true companion and facilitator of this growth. As trendwatcher they signalized the many initiatives that contributed to the development of activation analysis and its applications. A period has come to an end of impressive development resulting from sometimes revolutionary changes in radiation detection and data processing, and much improved irradiation facilities, NAA has reached a full stage of development, with emphasis on routine application and with remaining developments of in marginal impact. NAA is being challenged increasingly in the last 30 years by alternative techniques for multi trace element analysis. The MTAA Conference and with it the ICAA, the International Committee on Activation Analysis, can play an important and active role in this process of identifying and selecting key areas, and even promoting concerted action in those areas. Such an evolution of focus from retrospective to prospective, from trendwatcher to trendsetter, may well allow the MTAA Conference to continue and even expand its role in future development of NAA and its applications. The ideas about the future of the MTAA Conferences and its organization are elaborated upon and some possible subjects for focused development activities are indicated.Radiation, Radionuclides and ReactorsApplied Science
The Treat-to-Target Project in Atopic Dermatitis: One Year On
No full textAtopic dermatitis is a chronic skin condition for which a range of systemic treatments have recently been approved. A treat-to-target strategy has been deve loped previously alongside an algorithm to guide the management of patients with atopic dermatitis. Here, we review the strategy and algorithm in the context of the evolving therapeutic landscape, and identify areas for further refinement and development
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