Inorganic polyphosphate (polyP) physiology 35 Caveats in studies of the physiological role of polyphosphates in coagulation

Abstract Platelet-derived polyphosphates (polyP), stored in dense granule and released upon platelet activation, have been claimed to enhance thrombin activation of coagulation factor XI (FXI) and to activate FXII directly. The latter claim is controversial and principal results leading to these conclusions are probably influenced by methodological problems. It is important to consider that low-grade contact activation is initiated by all surfaces and is greatly amplified by the presence of phospholipids simulating the procoagulant membranes of activated platelets. Thus, proper use of inhibitors of the contact pathway and a careful choice of materials for plates and tubes is important to avoid artefacts. The use of phosphatases used to degrade polyP has an important drawback as it also degrades the secondary activators ADP and ATP, which are released from activated platelets. In addition, the use of positively charged inhibitors, such as polymyxin B, to inhibit polyP in platelet-rich plasma and blood is problematic, as polymyxin B also slows coagulation in the absence of polyP. In conclusion we hope awareness of the above caveats may improve research on the physiological roles of polyP in coagulation

Формирование рельефа поверхности при алмазном выглаживании упругим инструментом

Материалы XIII Междунар. науч.-техн. конф. (науч. чтения, посвящ. 125-летию со дня рождения П. О. Сухого), Гомель, 22 окт. 2020 г

Imaging methods for haemostasis research

Blood is a vital part of the human physiology; a transport system that brings nutrients and oxygen to sustain living cells and simultaneously facilitates the removal of carbon dioxide and other waste products from the body. To assure the continuity of these functions, it is of uttermost importance to keep the flowing blood inside the vascular system at any cost. The principal components of the haemostatic system are the blood platelets and the plasma coagulation system, both working in concert to create a blood stopping haemostatic plug when a vessel is ruptured. In modern health care, methods for treatment and diagnostics often implicate the contact between blood and artificial materials (biomaterials). Biomaterial surfaces may activate platelets and the coagulation cascade by exposing a surface that during blood contact shares certain characteristics with surfaces found at the site of vascular injury. Therefore it is of great importance that the mechanisms behind the interactions between foreign surfaces and blood are studied in order to minimize, and if possible, prevent unnecessary reactions that may lead to thrombosis. This thesis describes two important methods to study blood – surface interactions in terms of surface induced plasma coagulation and platelet adhesion/aggregation. The method ‘Imaging of coagulation’, a coagulation assay based on time-lapse image capture of the coagulation process was developed during the course of this work. The use of images enables the method to answer questions regarding where coagulation was initiated and how fast coagulation propagates. Such questions are highly relevant in the study of blood-biomaterial interactions but also in general haemostasis research. In vivo, platelet adhesion and aggregation are events that always proceed under flow conditions. Therefore we also developed a cone-and-plate flow model to study these mechanisms under similar conditions in vitro. The cone-and-plate setup was found to be a flexible platform and was used for both blood compatibility testing of potential biomaterials as well as for general haemostasis research. With the above mentioned methods we tested the haemocompatibility of glycerol monooleate (GMO), a proposed substance for use in biomaterial applications. It was found that GMO did not activate coagulation to any great extent either in plasma or in whole blood. Surface induced coagulation and platelet adhesion was also studied on PEG-containing hydrogels and compared with hydrogels constructed from three different non-PEG-containing monomers. It was concluded that all the grafted hydrogels, in particular those produced from the monomers 2-hydroxyethyl methacrylate (HEMA) and/or PEG- methacrylate (PEGMA), demonstrated good haemocompatibility. Supported phospholipid bilayers were used to investigate the relationship between surface charge and procoagulant activity. The coagulation process was studied in a straightforward manner using the imaging of coagulation setup. We concluded that the content of negatively charged 1-palmitoyl-2-oleoyl-sn-glycero-3-[phospho-L-serine] (POPS) in the bilayer must exceed ~ 6% for the bilayer to exert procoagulant activity. The physiological role of factor XII in human haemostasis and thrombosis was investigated in the imaging of coagulation setup and the cone and plate setup by the use of surfaces with thrombogenic coatings. We found that tissue factor initiated coagulation could be greatly accelerated by the presence of contact activating agents in a platelet dependent manner. In conclusion, the method ‘Imaging of coagulation’ and platelet adhesion/aggregation in the cone-and-plate flow model are both versatile methods with many possible applications. The combination of the two methods provides a solid foundation for biomaterial and haemostasis research

Scientization : putting global climate change on the scientific agenda and the role of the IPCC

Since the 1970s, climate change has dominated the international scientific and political agenda. In particular, the foundation of the Intergovernmental Panel on Climate Change at the end of the 1980s played a major role for the further enhancement of efforts in the field of climate change sciences. However, to understand the interaction of the worldwide coordination of climate change sciences as well as the role of the Intergovernmental Panel on Climate Change and its consequences, it is worthwhile to take a look at the self-conception of the Intergovernmental Panel on Climate Change's tasks and work. This paper gives an idea of the history of international climate change science, its representation in public discourse and the role of the Intergovernmental Panel on Climate Change by comprehensively illustrating its tasks, organization and self-image. Furthermore, the article tries to argue that the hitherto accepted concept of science followed within this body fails to integrate the idea of scientific ethics. It can be concluded that the conception of science represented by the Intergovernmental Panel on Climate Change has heavily influenced worldwide attention to climate change, its becoming part of the political agenda as well as the ethical consequences

Benefit or Experience? : An analysis of ideas about reading promotion for adults in municipal library plans

Introduction. The purpose of this thesis is to explain how reading promotion for adults is presented in municipal library plans. It examines how reading promotion for adults is described as an activity, in what contexts it is mentioned, how it is motivated and what conceptual ideas of reading promotion for adults that can be found. Finally, the study examines what view of literature that can be derived from these findings: whether literature is seen as a tool to fulfil other objectives and goals or as something that has a purpose in itself. Method. Descriptive idea analysis was chosen to answer the thesis’ questions. The resource material consists of municipal library plans, and the analysis focuses on the library plans from three Swedish regions. Analysis. The theoretical concepts are retrieved from the Danish library and cultural policy researcher Dorte Skot-Hansen's cultural policy theories, as well as from the Danish library researcher Beth Juncker's definitions of the two concepts instrumental and autotelic. The analysis is performed on the basis of three themes that were distinguished in the library plans: Democracy, Experience and Health.  Results. The results of the study show that reading promotion for adults is described in several different contexts, and in relation to different topics. They also show that the theme Democracy was central in the library plans. This included a focus on equal access to literature and on reading ability as a prerequisite to active participation in society. Reading promotion was mainly motivated by instrumental ideas. Even when describing reading as an experience or for pleasure, the library plans tend to use instrumental ideas as a motivation. A certain view of literature can therefore be discerned in the library plans. Literature appears as something that should primarily be used to achieve other objectives. Conclusions. Our thesis shows that the instrumental ideas about reading promotion are strong in municipal library plans, and that the view of literature is instrumental rather than autotelic. We argue for further research into whether this has any effects on the everyday reading promotion in public libraries, or if methods focusing on reading and literature as experience with a purpose in itself still are being applied. This is a two years master's thesis in Library and information science

Biomass Briquettes in Malawi

In Malawi 2.5 % of the forest disappears each year. The use of firewood and charcoal, deriving from forest resources, accounts for about 99 % of the household energy demand in Malawi and is a cause to the deforestation. The Government of Malawi recently launched a programme called Promotion of Alternative Energy Sources Programme (PAESP) with the aim to reduce the use of firewood and charcoal. One of the fuels included in the programme is the biomass briquette. The aim with this study is to evaluate the viability of biomass briquettes as a sustainable alternative energy source to firewood and charcoal for households in Malawi. Research for the study was carried out during three months in Malawi. Visits were made to a number of briquette production sites to study the manufacturing methods and to collect briquette samples. The briquettes were tested using various methods and then compared with results for firewood and charcoal. At the moment various production methods are used in Malawi, with a high difference in technical complexity and cost. Machines produced from wood using very basic mechanics can apply similar pressure as more advanced metal pressers. They also seem to be better suited than those made of metal, in terms of price and availability. The majority of the briquette producers in Malawi use waste paper as base material. Although the paper briquettes are good, other raw materials will be needed if the production is supposed to be significantly increased. The briquettes burn well using the most common stoves in Malawi, including the commonly used charcoal stove. While firewood is cheaper to use than other available fuels, the briquettes seem to be able to compete with the fuel costs for charcoal

Forum Scientium, a multidisciplinary doctoral programme at Linköping University, Sweden.

1: In vitro thrombus formation on surface covered with fibroblasts (fluorescence microscopy) 2: In vitro thrombus formation at low shear, large thrombus (fluorescence microscopy) 3: Platelet adhesion and fibrin formation on hydrophilic glass (DIC microscopy) 4: In vitro thrombus formation at high shear (confocal microscopy) 5: Platelet adhesion to polystyrene (fluorescence microscopy) 6: Time-lapse images from Imaging of coagulation method 7: Platelet adhesion to patterned hydrogel with immobilized fibrinogen (fluorescence microscopy) 8: Platelet adhesion in cone-and-plate setup (fluorescence microscopy) 9: In vitro thrombus formation at low shear (fluorescence microscopy) 10: 3D visualization of adhered platelets 11: In vitro thrombus formation at low shear, large thrombus (fluorescence microscopy) 12: Imaging of coagulation setup 13: Platelets loaded with Ca 2+ probe Fluo-4 (fluorescence microscopy) © Lars Faxälv 2009, unless otherwise noted. Published papers are reprinted with the permission of publishers

Benefit or Experience? : An analysis of ideas about reading promotion for adults in municipal library plans

Introduction. The purpose of this thesis is to explain how reading promotion for adults is presented in municipal library plans. It examines how reading promotion for adults is described as an activity, in what contexts it is mentioned, how it is motivated and what conceptual ideas of reading promotion for adults that can be found. Finally, the study examines what view of literature that can be derived from these findings: whether literature is seen as a tool to fulfil other objectives and goals or as something that has a purpose in itself. Method. Descriptive idea analysis was chosen to answer the thesis’ questions. The resource material consists of municipal library plans, and the analysis focuses on the library plans from three Swedish regions. Analysis. The theoretical concepts are retrieved from the Danish library and cultural policy researcher Dorte Skot-Hansen's cultural policy theories, as well as from the Danish library researcher Beth Juncker's definitions of the two concepts instrumental and autotelic. The analysis is performed on the basis of three themes that were distinguished in the library plans: Democracy, Experience and Health.  Results. The results of the study show that reading promotion for adults is described in several different contexts, and in relation to different topics. They also show that the theme Democracy was central in the library plans. This included a focus on equal access to literature and on reading ability as a prerequisite to active participation in society. Reading promotion was mainly motivated by instrumental ideas. Even when describing reading as an experience or for pleasure, the library plans tend to use instrumental ideas as a motivation. A certain view of literature can therefore be discerned in the library plans. Literature appears as something that should primarily be used to achieve other objectives. Conclusions. Our thesis shows that the instrumental ideas about reading promotion are strong in municipal library plans, and that the view of literature is instrumental rather than autotelic. We argue for further research into whether this has any effects on the everyday reading promotion in public libraries, or if methods focusing on reading and literature as experience with a purpose in itself still are being applied. This is a two years master's thesis in Library and information science