Tuulivoimalan simulointiympäristö : 22 kW kuormakoneen ohjaus

Opinnäytetyö on tehty Tampereen ammattikorkeakoulun sähkölaboratorioon. Työn tarkoituksena oli tehdä todellista tuulivoimalaa mallintava simulointijärjestelmä siten, että sitä on helppo ohjata ja valvoa tietokoneelta. Järjestelmä on tehty sähkölaboratorion GreenLab-puolelle. Järjestelmän toteutus on tehty sähkölaboratorion tarjoamilla komponenteilla ja ne ovat sähkölaboratorioon kuuluvia. Tuulivoimalan mallintamisen tärkeimpänä elementtinä oli roottorin pyörimisnopeuden muuttuminen, kun generaattorin kuormitus muuttuu. Roottorin toiminnan mallintaminen suoraan teoriasta löytyvillä kaavoilla ei ole todenmukainen, sillä yksinkertainen teoria ei suoraan mallinna tuulivoimalassa syntyviä häviöitä. Tuulivoimalan roottorin toiminnan mallintamiseen käytettiin taajuusmuuttajakäyttöä, jossa on 22 kW:n oikosulkumoottori. Mallissa roottorin pyörimisnopeuden ohjearvo on riippuvainen tuulennopeudesta ja tuulivoimalan generaattorin kuormamomentista. Käytön ohjaus on toteutettu National Instrumentsin valmistamalla myDAQ-laiteella. Se on kannettava mittaus- ja instrumentointilaite, jolla voidaan luoda ja käsitellä analogisia signaaleja sekä digitaalista dataa. Laiteen ohjelmointi on tehty LabVIEW-ohjelmistolla. Ohjelmisto tekee ohjauksen lisäksi käyttöliittymää, jonka kautta tuulivoimalan käyttöä voidaan ohjata ja monitoroida tietokoneen välityksellä. Käyttöliittymään voidaan syöttää käyttöön asennetun generaattorin maksimisuoritearvot, joiden kautta ohjelma laskee sopivaa roottorin pyörimisnopeutta eri tuulennopeusarvoilla. Käyttöliittymään voidaan ladata erilaisia tuuliolosuhdemalleja ja monitoroida roottorin käyttäytymistä eri käyttötilanteissa. Käytölle on tehty lopuksi kuormituskokeet eri tuulennopeuksissa. Mittaustuloksista voidaan todeta roottorin toiminnan olevan tuulivoimamallin mukainen. Lopuksi työssä käsitellään toimenpiteitä, kuten monipuolisempaa laitteistoa, joilla simulointiympäristöä voitaisiin tulevaisuudessa kehittää.This thesis was made for the electric laboratory of Tampere University of Applied Sciences. The purpose of this thesis was to make a wind energy simulation system which can be controlled and monitored via PC. The system was built on the GreenLab feature of the electric laboratory. All the components of the system are property of the electric laboratory. The most important element of modeling the wind energy production was the modulation of the rotor speed when the generator is loaded. It was difficult to use the theory for modeling the wind generation because the theory doesn't include all the losses in wind turbine. The operation of the wind rotor is modeled with the 22 kW induction motor which is operated with a drive. The rotation speed of the motor is dependent on the speed of the wind and the load of the generator. The control of the system is executed with myDAQ which is manufactured by National Instruments. It is a portable measurement and instrumentation device which can be used to create and manipulate signals and digital data. The programming is made with LabVIEW. LabVIEW is used to make the program and the user interface. The user interface is used to control and monitor the system via PC. User can set parameters of the generator in the user interface which the program uses to calculate the rotation speed of the rotor in different wind conditions. It is possible to download various wind condition models into the program and monitor the behavior of the rotor in different situations. Lastly the system has been tested with loading tests in different wind conditions. Results from the tests tells that the system operates as it is modeled. An improvement plan for the simulation system could be used to develop it even better system

Hydroacoustics and concurrent experimental trawling reveal extreme annual variation in the density of 0+ pikeperch in late summer

The density and mean size of 0 + pikeperch (Sander lucioperca) were studied in late summer in 2004-2017 in clay-turbid and eutrophic Lake Tuusulanjarvi in southern Finland. Hydroacoustics and simultaneous experimental trawling were used to estimate the density of 0 + pikeperch. In some autumns, 0 + pikeperch was the most abundant species in the pelagic fish assemblage. However, the annual amplitude of pikeperch density was extremely high (1,300 -19,900 individuals ha(-1)). The density and size variations of 0 + pikeperch were analysed in relation to air temperature sums and degree days. Unexpectedly, the density of 0 + pikeperch showed no correlation with the air temperature sums or degree days, but both the mean length and weight of 0 + pikeperch correlated positively with these temperature variables. The highest correlation coefficients between mean size and temperature were found with temperature sums over 10 degrees C and degree days over 5 degrees C. The correlation between density and condition of 0 + pikeperch was negative but non-significant. The high density of 0 + pikeperch in some autumns suggests that pikeperch may play a central role in the pelagic food web in eutrophic lakes - not only as a predator of planktivores but also by its own planktivory.Peer reviewe

Mechanism of Borrelia immune evasion by FhbA-related proteins

Author summaryRelapsing fever and Lyme Disease are infectious diseases caused by borrelia bacteria. Relapsing fever occurs sporadically worldwide, whereas distribution of Lyme Disease is restricted to the Northern Hemisphere. Both infections are transmitted to humans by blood eating ticks or lice. These infections are often difficult to diagnose due to nonspecific symptoms. To be able to cause infection, borrelia must circumvent the human immune responses. Here we describe a mechanism, how borrelia bacteria protect themselves in the human host by utilizing host proteins. By using X-ray crystallography, we solved the structure of an outer membrane protein FhbA from a relapsing fever causing borreliae, Borrelia hermsii, in complex with human complement regulator factor H. FhbA has a unique alpha-helical fold that has not been reported earlier. The structure of the complex revealed how FhbA binds factor H in a very specific manner. Factor H bound to FhbA on the surface of borrelia protects bacteria from the complement system and lysis. Based on the structure, we performed structure-guided sequence database analysis, which suggests that similar proteins are present in all relapsing fever causing borrelia and possibly in some Lyme disease agents. Immune evasion facilitates survival of Borrelia, leading to infections like relapsing fever and Lyme disease. Important mechanism for complement evasion is acquisition of the main host complement inhibitor, factor H (FH). By determining the 2.2 angstrom crystal structure of Factor H binding protein A (FhbA) from Borrelia hermsii in complex with FH domains 19-20, combined with extensive mutagenesis, we identified the structural mechanism by which B. hermsii utilizes FhbA in immune evasion. Moreover, structure-guided sequence database analysis identified a new family of FhbA-related immune evasion molecules from Lyme disease and relapsing fever Borrelia. Conserved FH-binding mechanism within the FhbA-family was verified by analysis of a novel FH-binding protein from B. duttonii. By sequence analysis, we were able to group FH-binding proteins of Borrelia into four distinct phyletic types and identified novel putative FH-binding proteins. The conserved FH-binding mechanism of the FhbA-related proteins could aid in developing new approaches to inhibit virulence and complement resistance in Borrelia.Peer reviewe

Twinfilin uncaps filament barbed ends to promote turnover of lamellipodial actin networks

Coordinated polymerization of actin filaments provides force for cell migration, morphogenesis and endocytosis. Capping protein (CP) is a central regulator of actin dynamics in all eukaryotes. It binds to actin filament (F-actin) barbed ends with high affinity and slow dissociation kinetics to prevent filament polymerization and depolymerization. However, in cells, CP displays remarkably rapid dynamics within F-actin networks, but the underlying mechanism remains unclear. Here, we report that the conserved cytoskeletal regulator twinfilin is responsible for CP’s rapid dynamics and specific localization in cells. Depletion of twinfilin led to stable association between CP and cellular F-actin arrays, as well as to its retrograde movement throughout leading-edge lamellipodia. These were accompanied by diminished F-actin turnover rates. In vitro single-filament imaging approaches revealed that twinfilin directly promotes dissociation of CP from filament barbed ends, while enabling subsequent filament depolymerization. These results uncover a bipartite mechanism that controls how actin cytoskeleton-mediated forces are generated in cells.Peer reviewe

Radiographic findings have an association with weight bearing and locomotion in English bulldogs

Background English bulldogs are known to be prone to skeletal problems, but knowledge is lacking of the effect of these problems on locomotion and function. This study was undertaken to report the conformational, orthopaedic and radiographic findings in a cohort of English bulldogs in Finland and to evaluate how these findings affect weight bearing and locomotion of the dogs. Twenty-eight English bulldogs were prospectively recruited to this cross-sectional study. An orthopaedic examination, measurements of conformation, static and dynamic weight bearing, and radiographic examinations of elbow, hip, stifle joints and spine were done. Results The English bulldogs carried a mean of 67.3% and 62.1% of their body weight in front limbs while standing and trotting, respectively. Front and hind limb lameness was seen in 20.8% (5/24) and 12.5% (3/24) of dogs, respectively. At orthopaedic examination, abnormal palpation findings (i.e. pain response, crepitation, swelling or subjectively decreased range of motion) were observed in a median of one joint (range 0-5) in each dog. Medial patellar luxation was diagnosed in 33.0% (8/24) of the evaluated dogs. At radiographic examination, elbow dysplasia was diagnosed in 48.2% (27/56) of elbow joints and severe hip dysplasia in 55.4% (31/56) of hip joints. The grade of elbow dysplasia was negatively associated with the ratio of static weight bearing between the front and hind limbs (slope estimate - 1.46, 95% CI - 2.75 to - 0.16, P = 0.03) and in dynamic weight bearing the ratio of total pressure index between the front and hind limbs (slope estimate - 0.088, 95% CI - 0.164 to 0.025, P = 0.03). The severity of hip dysplasia or hip osteoarthritis was not associated with the amount of static or dynamic weight bearing, but all except one dog were diagnosed with Federation Cynologique Internationale grade C, D or E hips (dysplastic). In the spine, 78.6% (22/28) of the dogs had at least one malformed vertebra. Conclusions Orthopaedic diseases and abnormal radiographic findings were common in the English bulldogs studied. The static weight bearing of the dogs was heavily distributed to the front limbs. With increasing severity of elbow dysplasia, the static and dynamic weight bearing shifted from dysplastic elbows to hind limbs.Peer reviewe

Structural basis of rapid actin dynamics in the evolutionarily divergent Leishmania parasite

The authors report here the structure-function analysis of highly divergent actin from Leishmania parasite. The study reveals remarkably rapid dynamics of parasite actin as well as the underlying molecular basis, thus providing insight into evolution of the actin cytoskeleton. Actin polymerization generates forces for cellular processes throughout the eukaryotic kingdom, but our understanding of the 'ancient' actin turnover machineries is limited. We show that, despite > 1 billion years of evolution, pathogenic Leishmania major parasite and mammalian actins share the same overall fold and co-polymerize with each other. Interestingly, Leishmania harbors a simple actin-regulatory machinery that lacks cofilin 'cofactors', which accelerate filament disassembly in higher eukaryotes. By applying single-filament biochemistry we discovered that, compared to mammalian proteins, Leishmania actin filaments depolymerize more rapidly from both ends, and are severed > 100-fold more efficiently by cofilin. Our high-resolution cryo-EM structures of Leishmania ADP-, ADP-Pi- and cofilin-actin filaments identify specific features at actin subunit interfaces and cofilin-actin interactions that explain the unusually rapid dynamics of parasite actin filaments. Our findings reveal how divergent parasites achieve rapid actin dynamics using a remarkably simple set of actin-binding proteins, and elucidate evolution of the actin cytoskeleton.Peer reviewe

Structural basis underlying specific biochemical activities of non-muscle tropomyosin isoforms

Publisher Copyright: © 2022 The Author(s)The actin cytoskeleton is critical for cell migration, morphogenesis, endocytosis, organelle dynamics, and cytokinesis. To support diverse cellular processes, actin filaments form a variety of structures with specific architectures and dynamic properties. Key proteins specifying actin filaments are tropomyosins. Non-muscle cells express several functionally non-redundant tropomyosin isoforms, which differentially control the interactions of other proteins, including myosins and ADF/cofilin, with actin filaments. However, the underlying molecular mechanisms have remained elusive. By determining the cryogenic electron microscopy structures of actin filaments decorated by two functionally distinct non-muscle tropomyosin isoforms, Tpm1.6 and Tpm3.2, we reveal that actin filament conformation remains unaffected upon binding. However, Tpm1.6 and Tpm3.2 follow different paths along the actin filament major groove, providing an explanation for their incapability to co-polymerize on actin filaments. We also elucidate the molecular basis underlying specific roles of Tpm1.6 and Tpm3.2 in myosin II activation and protecting actin filaments from ADF/cofilin-catalyzed severing.Peer reviewe

Tropomyosin Isoforms Specify Functionally Distinct Actin Filament Populations In Vitro

Actin filaments assemble into a variety of networks to provide force for diverse cellular processes [1]. Tropomyosins are coiled-coil dimers that form head-to-tail polymers along actin filaments and regulate interactions of other proteins, including actin-de polymerizing factor (ADF)/cofilins and myosins, with actin [2-5]. In mammals, >40 tropomyosin isoforms can be generated through alternative splicing from four tropomyosin genes. Different isoforms display non-redundant functions and partially non-overlapping localization patterns, for example within the stress fiber network [6, 7]. Based on cell biological studies, it was thus proposed that tropomyosin isoforms may specify the functional properties of different actin filament populations [2]. To test this hypothesis, we analyzed the properties of actin filaments decorated by stress-fiber-associated tropomyosins (Tpm1.6, Tpm1.7, Tpm2.1, Tpm3.1, Tpm3.2, and Tpm4.2). These proteins bound F-actin with high affinity and competed with a-actinin for actin filament binding. Importantly, total internal reflection fluorescence (TIRF) microscopy of fluorescently tagged proteins revealed that most tropomyosin isoforms cannot co-polymerize with each other on actin filaments. These isoforms also bind actin with different dynamics, which correlate with their effects on actin-binding proteins. The long isoforms Tpm1.6 and Tpm1.7 displayed stable interactions with actin filaments and protected filaments from ADF/cofilin-mediated disassembly, but did not activate non-muscle myosin Ila (NMIIa). In contrast, the short isoforms Tpm3.1, Tpm3.2, and Tpm4.2 displayed rapid dynamics on actin filaments and stimulated the ATPase activity of NMIla, but did not efficiently protect filaments from ADF/cofilin. Together, these data provide experimental evidence that tropomyosin isoforms segregate to different actin filaments and specify functional properties of distinct actin filament populations.Peer reviewe

Common ELIXIR Service for Researcher Authentication and Authorisation

Linden M, Prochazka M, Lappalainen I, et al. Common ELIXIR Service for Researcher Authentication and Authorisation. F1000Research. 2018;7: 1199.A common Authentication and Authorisation Infrastructure (AAI) that would allow single sign-on to services has been identified as a key enabler for European bioinformatics. ELIXIR AAI is an ELIXIR service portfolio for authenticating researchers to ELIXIR services and assisting these services on user privileges during research usage. It relieves the scientific service providers from managing the user identities and authorisation themselves, enables the researcher to have a single set of credentials to all ELIXIR services and supports meeting the requirements imposed by the data protection laws. ELIXIR AAI was launched in late 2016 and is part of the ELIXIR Compute platform portfolio. By the end of 2017 the number of users reached 1000, while the number of relying scientific services was 36. This paper presents the requirements and design of the ELIXIR AAI and the policies related to its use, and how it can be used for serving some example services, such as document management, social media, data discovery, human data access, cloud compute and training services

Mechanism of synergistic actin filament pointed end depolymerization by cyclase-associated protein and cofilin

The ability of cells to generate forces through actin filament turnover was an early adaptation in evolution. While much is known about how actin filaments grow, mechanisms of their disassembly are incompletely understood. The best-characterized actin disassembly factors are the cofilin family proteins, which increase cytoskeletal dynamics by severing actin filaments. However, the mechanism by which severed actin filaments are recycled back to monomeric form has remained enigmatic. We report that cyclase-associated-protein (CAP) works in synergy with cofilin to accelerate actin filament depolymerization by nearly 100-fold. Structural work uncovers the molecular mechanism by which CAP interacts with actin filament pointed end to destabilize the interface between terminal actin subunits, and subsequently recycles the newly-depolymerized actin monomer for the next round of filament assembly. These findings establish CAP as a molecular machine promoting rapid actin filament depolymerization and monomer recycling, and explain why CAP is critical for actin-dependent processes in all eukaryotes.Peer reviewe