99 research outputs found
Uneven cellular expression of recombinant α2A-adrenoceptors in transfected CHO cells results in loss of response in adenylyl cyclase inhibition
AbstractTwo populations of Chinese hamster ovary (CHO) cells expressing similar numbers of recombinant human alpha2A-adrenergic receptors (α2A-AR) showed different capacity to inhibit adenylyl cyclase (AC) activity. Cells transfected with an integrating vector exhibited agonist-dependent inhibition of forskolin-stimulated AC, whereas cells transfected with a non-integrating episomal vector showed no inhibition. Fluorescent microscopy and flow cytometry revealed a very uneven receptor distribution in the episomally transfected cell population. Monoclonal cell populations were expanded from this parent population. Most clones lacked significant amounts of receptors, while a few expressed receptors at high density; these exhibited efficient agonist-dependent inhibition of forskolin-stimulated AC activity. Thus, dense receptor expression in only a few cells is not sufficient to evoke a significant inhibitory response in a functional assay where AC is stimulated in all cells. Consequently, a false negative result was produced. Furthermore, the cell population transfected with an integrating vector showed loss of homogeneity with increasing passage number
RNA-Dependent RNA Polymerase from Heterobasidion RNA Virus 6 Is an Active Replicase In Vitro
Heterobasidion RNA virus 6 (HetRV6) is a double-stranded (ds)RNA mycovirus and a member of the recently established genus Orthocurvulavirus within the family Orthocurvulaviridae. The purpose of the study was to determine the biochemical requirements for RNA synthesis catalyzed by HetRV6 RNA-dependent RNA polymerase (RdRp). HetRV6 RdRp was expressed in Escherichia coli and isolated to near homogeneity using liquid chromatography. The enzyme activities were studied in vitro using radiolabeled UTP. The HetRV6 RdRp was able to initiate RNA synthesis in a primer-independent manner using both virus-related and heterologous single-stranded (ss)RNA templates, with a polymerization rate of about 46 nt/min under optimal NTP concentration and temperature. NTPs with 2′-fluoro modifications were also accepted as substrates in the HetRV6 RdRp-catalyzed RNA polymerization reaction. HetRV6 RdRp transcribed viral RNA genome via semi-conservative mechanism. Furthermore, the enzyme demonstrated terminal nucleotidyl transferase (TNTase) activity. Presence of Mn2+ was required for the HetRV6 RdRp catalyzed enzymatic activities. In summary, our study shows that HetRV6 RdRp is an active replicase in vitro that can be potentially used in biotechnological applications, molecular biology, and biomedicine
RNA-Dependent RNA Polymerase from Heterobasidion RNA Virus 6 Is an Active Replicase In Vitro
Heterobasidion RNA virus 6 (HetRV6) is a double-stranded (ds)RNA mycovirus and a member of the recently established genus Orthocurvulavirus within the family Orthocurvulaviridae. The purpose of the study was to determine the biochemical requirements for RNA synthesis catalyzed by HetRV6 RNA-dependent RNA polymerase (RdRp). HetRV6 RdRp was expressed in Escherichia coli and isolated to near homogeneity using liquid chromatography. The enzyme activities were studied in vitro using radiolabeled UTP. The HetRV6 RdRp was able to initiate RNA synthesis in a primer-independent manner using both virus-related and heterologous single-stranded (ss)RNA templates, with a polymerization rate of about 46 nt/min under optimal NTP concentration and temperature. NTPs with 2′-fluoro modifications were also accepted as substrates in the HetRV6 RdRp-catalyzed RNA polymerization reaction. HetRV6 RdRp transcribed viral RNA genome via semi-conservative mechanism. Furthermore, the enzyme demonstrated terminal nucleotidyl transferase (TNTase) activity. Presence of Mn2+ was required for the HetRV6 RdRp catalyzed enzymatic activities. In summary, our study shows that HetRV6 RdRp is an active replicase in vitro that can be potentially used in biotechnological applications, molecular biology, and biomedicine
On the Importance of Spatial and Velocity Resolution in the Hybrid-Vlasov Modeling of Collisionless Shocks
In hybrid-Vlasov plasma modeling, the ion velocity distribution function is propagated using the Vlasov equation while electrons are considered a charge-neutralizing fluid. It is an alternative to particle-in-cell methods, one advantage being the absence of sampling noise in the moments of the distribution. However, the discretization requirements in up to six dimensions (3D position, 3V velocity) make the computational cost of hybrid-Vlasov models higher. This is why hybrid-Vlasov modeling has only recently become more popular and available to model large-scale systems. The hybrid-Vlasov model Vlasiator is the first to have been successfully applied to model the solar-terrestrial interaction. It includes in particular the bow shock and magnetosheath regions, albeit in 2D-3V configurations so far. The purpose of this study is to investigate how Vlasiator parameters affect the modeling of a plasma shock in a 1D-3V simulation. The setup is similar to the Earth's bow shock in previous simulations, so that the present results can be related to existing and future magnetospheric simulations. The parameters investigated are the spatial and velocity resolution, as well as the phase space density threshold, which is the key parameter of the so-called sparse velocity space. The role of the Hall term in Ohm's law is also studied. The evaluation metrics used are the convergence of the final state, the complexity of spatial profiles and ion distributions as well as the position of the shock front. In agreement with previous Vlasiator studies it is not necessary to resolve the ion inertial length and gyroradius in order to obtain kinetic phenomena. While the code remains numerically stable with all combinations of resolutions, it is shown that significantly increasing the resolution in one space but not the other leads to unphysical results. Past a certain level, decreasing the phase space density threshold bears a large computational weight without clear physical improvement in the setup used here. Finally, the inclusion of the Hall term shows only minor effects in this study, mostly because of the 1D configuration and the scales studied, at which the Hall term is not expected to play a major role.In hybrid-Vlasov plasma modeling, the ion velocity distribution function is propagated using the Vlasov equation while electrons are considered a charge-neutralizing fluid. It is an alternative to particle-in-cell methods, one advantage being the absence of sampling noise in the moments of the distribution. However, the discretization requirements in up to six dimensions (3D position, 3V velocity) make the computational cost of hybrid-Vlasov models higher. This is why hybrid-Vlasov modeling has only recently become more popular and available to model large-scale systems. The hybrid-Vlasov model Vlasiator is the first to have been successfully applied to model the solar-terrestrial interaction. It includes in particular the bow shock and magnetosheath regions, albeit in 2D-3V configurations so far. The purpose of this study is to investigate how Vlasiator parameters affect the modeling of a plasma shock in a 1D-3V simulation. The setup is similar to the Earth's bow shock in previous simulations, so that the present results can be related to existing and future magnetospheric simulations. The parameters investigated are the spatial and velocity resolution, as well as the phase space density threshold, which is the key parameter of the so-called sparse velocity space. The role of the Hall term in Ohm's law is also studied. The evaluation metrics used are the convergence of the final state, the complexity of spatial profiles and ion distributions as well as the position of the shock front. In agreement with previous Vlasiator studies it is not necessary to resolve the ion inertial length and gyroradius in order to obtain kinetic phenomena. While the code remains numerically stable with all combinations of resolutions, it is shown that significantly increasing the resolution in one space but not the other leads to unphysical results. Past a certain level, decreasing the phase space density threshold bears a large computational weight without clear physical improvement in the setup used here. Finally, the inclusion of the Hall term shows only minor effects in this study, mostly because of the 1D configuration and the scales studied, at which the Hall term is not expected to play a major role.In hybrid-Vlasov plasma modeling, the ion velocity distribution function is propagated using the Vlasov equation while electrons are considered a charge-neutralizing fluid. It is an alternative to particle-in-cell methods, one advantage being the absence of sampling noise in the moments of the distribution. However, the discretization requirements in up to six dimensions (3D position, 3V velocity) make the computational cost of hybrid-Vlasov models higher. This is why hybrid-Vlasov modeling has only recently become more popular and available to model large-scale systems. The hybrid-Vlasov model Vlasiator is the first to have been successfully applied to model the solar-terrestrial interaction. It includes in particular the bow shock and magnetosheath regions, albeit in 2D-3V configurations so far. The purpose of this study is to investigate how Vlasiator parameters affect the modeling of a plasma shock in a 1D-3V simulation. The setup is similar to the Earth's bow shock in previous simulations, so that the present results can be related to existing and future magnetospheric simulations. The parameters investigated are the spatial and velocity resolution, as well as the phase space density threshold, which is the key parameter of the so-called sparse velocity space. The role of the Hall term in Ohm's law is also studied. The evaluation metrics used are the convergence of the final state, the complexity of spatial profiles and ion distributions as well as the position of the shock front. In agreement with previous Vlasiator studies it is not necessary to resolve the ion inertial length and gyroradius in order to obtain kinetic phenomena. While the code remains numerically stable with all combinations of resolutions, it is shown that significantly increasing the resolution in one space but not the other leads to unphysical results. Past a certain level, decreasing the phase space density threshold bears a large computational weight without clear physical improvement in the setup used here. Finally, the inclusion of the Hall term shows only minor effects in this study, mostly because of the 1D configuration and the scales studied, at which the Hall term is not expected to play a major role.Peer reviewe
Identifying drivers and hindrances of social user experience in web services
ABSTRACT Social activity is becoming a central contributor to user experience (UX) in many modern Web services. The motivations, norms and rules of online communities have been widely researched, however, social activity and its UX in modern Web services is a less studied area. We conducted a four-week-long field study with three Web services -Facebook, Nokia Sports Tracker and Dopplrwhich all support social activity. The aim of this study was to identify the central drivers and hindrances of social UX, user experience of online social activity. Our results show that the main drivers of social UX include self-expression, reciprocity, learning and curiosity, whereas unsuitability of content and functionality, incompleteness of user networks and lack of trust and privacy are often experienced as hindrances for social UX. Our findings also reveal the pragmatic and hedonic nature of the drivers and hindrances. The results can be used to inform design and evaluation of social UX in Web services
Verification of Tether Deployment System aboard CubeSat through Dynamics Simulations and Tests
This paper proposes a proper model selection strategies for the dynamic simulations of the tether deployment mission aboard a CubeSat. Space tether technology will enable innovative space missions in the near future. The Coulomb Drag Propulsion (CDP), including electric solar wind sailing, is one of the plausible future technologies. The authors currently develop a CubeSat, FORESAIL-1, for space demonstration of CDP. However, the analytical simulations for the verification and validation of the mission design typically require a high computational cost. This is because a minimum model order is not selected properly. In this study, through observing a preliminary analytical model for tether deployment analysis, the simplest model is chosen to avoid the mission failure modes in each deployment phase.Peer reviewe
Soil-tree-atmosphere CH4 flux dynamics of boreal birch and spruce trees during spring leaf-out
Peer reviewe
Perheenyhdistämisen edellytysten tiukentaminen ja sen vaikutukset Suomessa sekä kokemuksia viidestä Euroopan maasta
Osana valtioneuvoston kanslian selvitys- ja tutkimustoimintaa toteutettu hanke Perheenyhdistämisen edellytysten tiukentaminen tarkastelee EU:n perheenyhdistämistä koskevan direktiivin (2003/86/EU) mukaisten perheenyhdistämisen valinnaisten lisäedellytysten soveltamisen edellytyksiä ja vaikutuksia Suomessa. Valinnaisia lisäedellytyksiä ovat kotoutumisedellytys, asuntoedellytys, asumisaikavaatimus, vähimmäisikää koskeva vaatimus ja sairausvakuutusvaatimus. Lisäedellytysten osalta tarkastelun kohteena ovat erityisesti kansainvälistä suojelua saavat henkilöt ja heidän perheenjäsenensä. Selvityksessä tarkastellaan myös toimeentuloedellytyksen soveltamista Suomen kansalaisten ja kolmansien maiden kansalaisten välisissä avioliitoissa.
Selvityksessä kuvataan lisäedellytysten soveltamisesta vertailumaissa saatuja kokemuksia. Lisäksi tarkastellaan lisäedellytysten mahdollisen käyttöönoton signaalivaikutuksia sekä taloudellisia ja demografisia vaikutuksia vertailumaista kootun tiedon ja tutkimuskirjallisuuden pohjalta. Vertailutietoa koottiin viidestä Suomen kanssa vertailukelpoisesta maasta: Ruotsista, Tanskasta, Norjasta, Saksasta ja Alankomaista.
Lisäedellytyksistä asumisaikaedellytys ja vähimmäisikää koskeva vaatimus ovat helposti ja kustannustehokkaasti toteutettavissa. Niiden vaikutus perheenyhdistämisten määrään on kuitenkin marginaalinen, koska toimeentuloedellytys rajaa kohderyhmän varsin pieneksi. Asuntoedellytyksen vaikutukset ja sen soveltamisesta saadut kokemukset ovat ristiriitaisia. Sairausvakuutusedellytystä ei sovelleta yhdessäkään vertailumaassa, eikä sen soveltaminen Suomessakaan olisi ongelmatonta. Kotoutumisedellytystä sovelletaan suhteellisen laajasti. Sillä on havaittu olevan erilaisia myönteisiä ja kielteisiä kotoutumiseen liittyviä vaikutuksia, joita on kuvattu tarkemmin raportissa.
Tutkimuksen toteuttivat Oxford Research ja Väestöliitto sekä Lucify oy, joka toteutti työhön liittyvän interaktiivisen visualisoinnin eri maahanmuuttajaryhmien mahdollisuuksia toimeentuloedellytyksen täyttämiseen. Kansainvälisestä aineistonkeruusta vastasivat Oxford Researchin maatoimistot Pohjoismaissa sekä Radboud University Nijmegen Alankomaissa ja Saksassa. Selvitys toteutettiin kesäkuun ja marraskuun 2016 välisenä aikana
Pyrolyysi turkiseläinten lannan käsittelymenetelmänä : TURKISTEHO-hankkeen osaraportti
Turkiseläinten kasvatus on Suomessa keskittynyt Pohjanmaan maakuntiin, joissa on paljon muutakin kotieläintaloutta. Alueella muodostuu lantafosforia yli kasvintuotannon tarpeen, ja sen kuljettamiseksi alueelta lantaa tulisi prosessoida väkevämmiksi lannoitevalmisteiksi. Yksi keino voisi olla pyrolyysi, jossa lantaa kuumennetaan (350–700 °C) vähähappisissa tai hapettomissa oloissa. Tällöin osa lannan eloperäisestä aineesta hajoaa muodostaen kiinteää hiilijaetta, haihtuvia kaasuja ja nesteitä. Hiilijakeen massa ja tilavuus ovat tällöin huomattavasti alkuperäistä lantaa pienemmät ja fosforipitoisuus korkeampi. Osana TURKISTEHO-hanketta tutkittiin pyrolyysiä yhtenä turkiseläinten lannan prosessointimenetelmänä ja arvioitiin hiilijakeen soveltuvuutta lannoitevalmisteeksi, pyrolyysikaasun ja -nesteen energiamäärää sekä nesteen soveltuvuutta biokaasulaitoksen syötteeksi. Lisäksi kartoitettiin toimintaan liittyvän lainsäädännön nykytilanne.
Varjotalojen alta kerättyä, esikuivattua ja homogenisoitua ketun- ja minkinlantaa pyrolysoitiin laboratoriolaitteistolla kahdessa eri lämpötilassa (340 ja 470 °C). Eri tavoin käsiteltyjen lantojen (tuoreet, kuivatut ja hiilijakeet) ominaisuuksia lannoitevalmisteina (mm. ravinteet, fosforin liukoisuus) tutkittiin laboratorioanalyysein. Lisäksi fosforin käyttökelpoisuutta kasville selvitettiin astiakokeella (koekasvina raiheinä, verrokkina superfosfaatti). Pyrolyysikaasusta mitattiin kaasun pääkomponentit, joiden mukaan arvioitiin kaasun energiasisältö (alempi lämpöarvo). Pyrolyysinesteistä määritettiin alempi lämpöarvo ja metaanintuottopotentiaali laboratoriokokein.
Ketun- ja minkinlanta soveltuvat esikuivattuina pyrolysoitaviksi. Pyrolyysilämpötilan nousu vaikuttaa muodostuvien jakeiden ominaisuuksiin ja määriin. Esimerkiksi fosforin pitoisuus hiilijakeessa kasvaa lämpötilan noustessa, mutta typpeä siirtyy enemmän kaasu- ja nestejakeisiin. Typpeä haihtuu myös esikuivauksessa. Hiilijakeiden fosforipitoisuudet olivat korkeita (64–96 g/kg kuiva-aineessa), minkä lisäksi ne sisälsivät myös sivu- ja hivenravinteita. Typpitoisuudet olivat alhaiset (3–6 % kuiva-aineessa), ja haitallisten metallien pitoisuudet alittivat kansallisen lainsäädännön raja-arvot. Fosforin liukoisuus heikkeni tuoreeseen lantaan verrattuna, mutta oli minkinlannan hiilijakeilla käyttökelpoisuudeltaan lähellä superfosfaattifosforin sekä tuoreen ja kuivatun lannan käyttökelpoisuutta. Ketunlannan pyrolyysi heikensi fosforin käyttökelpoisuutta suhteessa superfosfaattifosforiin. Pyrolyysikaasun ja –nesteiden polttaminen voisi tuottaa lannan esikuivaukseen tarvittavan energian. Pyrolyysinesteet voisivat soveltua myös lisäsyötteeksi biokaasun tuotantoon ainakin vähäisenä osana syöteseosta. Pyrolyysinesteen eri faasien erottelu voisi tehostaa nesteen hyötykäyttöä.
Tulokset vaativat tuekseen lisätutkimusta mm. typen talteenoton mahdollisuuksista, nesteiden energiahyödyntämisestä ja hiilijakeen fosforin käyttökelpoisuudesta. Käytännön mittakaavan laitteistolla tehdyt kokeet antaisivat lisätietoa mm. prosessin hyötysuhteista ja energian tarpeesta sekä pyrolyysinesteen hyödynnettävyydestä. Myös lannan pyrolyysiin ja siinä syntyvien eri jakeiden hyödyntämiseen liittyvä lainsäädäntö on osittain vielä tarkentumatta.202
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