Striatal dopamine synthesis capacity reflects smartphone social activity

Striatal dopamine and smartphone behavior have both been linked with behavioral variability. Here, we leverage day-to-day logs of natural, unconstrained smartphone behavior and establish a correlation between a measure of smartphone social activity previously linked with behavioral variability and a measure of striatal dopamine synthesis capacity using [(18)F]-DOPA PET in (N = 22) healthy adult humans. Specifically, we find that a higher proportion of social app interactions correlates with lower dopamine synthesis capacity in the bilateral putamen. Permutation tests and penalized regressions provide evidence that this link between dopamine synthesis capacity and social versus non-social smartphone interactions is specific. These observations provide a key empirical grounding for current speculations about dopamine's role in digital social behavior

Minäpystyvyys osana luokanhallintaa:tarkastelussa noviisiopettaja

Tiivistelmä. Tutkielman tarkoituksena on tarkastella opettajan minäpystyvyyden vaikutusta luokanhallintaan sekä ymmärtää konkreettisia keinoja, joilla opettaja voi vaikuttaa luokanhallintataitojen luomiseen. Haluamme ilmentää, miten minäpystyvyys esittäytyy noviisiopettajan toiminnassa luokanhallinnan osalta. Tutkielman aihe on ollut merkittävä jo useamman vuosikymmenen ajan, koska luokanhallinta on yksi opettajan tärkeimmistä taidoista. Tutkielma on toteutettu kuvailevana kirjallisuuskatsauksena. Tutkielmassa pyritään saamaan vastauksia siihen, miten minäpystyvyys vaikuttaa luokanhallintaan sekä, miten noviisiopettajan minäpystyvyys näyttäytyy osana luokanhallintaa. Teoreettinen viitekehys rakentuu tutkielmassa keskeisten käsitteiden ympärille. Tutkielman keskeiset käsitteet ovat luokanhallinta, minäpystyvyys sekä noviisiopettaja. Luokanhallinnan ja minäpystyvyyden käsitteiden määritteleminen perustuu aiheen tutkijoiden teorioihin. Luokanhallinnalla on vaikutusta pedagogisiin oppimisympäristöihin, oppilaiden akateemisiin suorituksiin sekä opettajan omaan työtyytyväisyyteen. Toimivat luokanhallintataidot pohjautuvat opettajan kokemaan minäpystyvyyteen. Tutkimustiedon perusteella voidaan todeta, että minäpystyvyydellä ja luokanhallinnalla on selkeä yhteys. Opettajan minäpystyvyys vaikuttaa siihen millaisia luokanhallintakeinoja hän käyttää tai miten paljon hän on valmis käyttämään työpanosta. Hyvä minäpystyvyys mahdollistaa positiivisten luokanhallintakeinojen käyttämisen. Opettajan on mahdollista kehittää omaa minäpystyvyyden tasoa sekä omia luokanhallintakeinoja. Noviisiopettajalle ensimmäiset työvuodet ovat raskaimpia, koska työn automatisoituminen on puutteellista. Oman käytöksen ja seurausten ennakointi on vähäistä. Noviisiopettaja tarvitsee ja kaipaa ensimmäisten työvuosien ajan muilta kollegoilta tukea. Varhainen mentorointi vaikuttaa positiivisesti opettajan minäpystyvyyden rakentumiseen. Noviisiopettajien kokemukset opettajankoulutuksesta tuovat ilmi myös sen, ettei koulutus vastaa tarpeeksi työelämää ja sen tuomia haasteita

Structural and functional characteristics of xenavidin, the first frog avidin from Xenopus tropicalis

<p>Abstract</p> <p>Background</p> <p>Avidins are proteins with extraordinarily high ligand-binding affinity, a property which is used in a wide array of life science applications. Even though useful for biotechnology and nanotechnology, the biological function of avidins is not fully understood. Here we structurally and functionally characterise a novel avidin named xenavidin, which is to our knowledge the first reported avidin from a frog.</p> <p>Results</p> <p>Xenavidin was identified from an EST sequence database for <it>Xenopus tropicalis </it>and produced in insect cells using a baculovirus expression system. The recombinant xenavidin was found to be homotetrameric based on gel filtration analysis. Biacore sensor analysis, fluorescently labelled biotin and radioactive biotin were used to evaluate the biotin-binding properties of xenavidin - it binds biotin with high affinity though less tightly than do chicken avidin and bacterial streptavidin. X-ray crystallography revealed structural conservation around the ligand-binding site, while some of the loop regions have a unique design. The location of structural water molecules at the entrance and/or within the ligand-binding site may have a role in determining the characteristic biotin-binding properties of xenavidin.</p> <p>Conclusion</p> <p>The novel data reported here provide information about the biochemically and structurally important determinants of biotin binding. This information may facilitate the discovery of novel tools for biotechnology.</p

Comparing simulated and experimental molecular cluster distributions

Peer reviewe

Modification of the loops in the ligand-binding site turns avidin into a steroid-binding protein

<p>Abstract</p> <p>Background</p> <p>Engineered proteins, with non-immunoglobulin scaffolds, have become an important alternative to antibodies in many biotechnical and therapeutic applications. When compared to antibodies, tailored proteins may provide advantageous properties such as a smaller size or a more stable structure.</p> <p>Results</p> <p>Avidin is a widely used protein in biomedicine and biotechnology. To tailor the binding properties of avidin, we have designed a sequence-randomized avidin library with mutagenesis focused at the loop area of the binding site. Selection from the generated library led to the isolation of a steroid-binding avidin mutant (sbAvd-1) showing micromolar affinity towards testosterone (K_d~ 9 μM). Furthermore, a gene library based on the sbAvd-1 gene was created by randomizing the loop area between <it>β</it>-strands 3 and 4. Phage display selection from this library led to the isolation of a steroid-binding protein with significantly decreased biotin binding affinity compared to sbAvd-1. Importantly, differential scanning calorimetry and analytical gel-filtration revealed that the high stability and the tetrameric structure were preserved in these engineered avidins.</p> <p>Conclusions</p> <p>The high stability and structural properties of avidin make it an attractive molecule for the engineering of novel receptors. This methodology may allow the use of avidin as a universal scaffold in the development of novel receptors for small molecules.</p

The Role of Academic Buoyancy and Emotions in Students’ Learning-Related Expectations and Behaviours in Primary School

Background. Academic buoyancy refers to students’ ability to come through ordinary challenges they face in the academic context, and it can positively contribute to students’ beliefs and behaviours in learning situations. Although buoyancy has been found to be related to positive academic outcomes, previous studies have not examined how buoyancy influences academic emotions in learning situations and how these emotions further affect students’ learning-related expectations and behaviours. Aims. This study investigated to what extent academic buoyancy predicts students’ failure expectations, avoidance behaviour, and task-oriented planning in learning situations, and to what extent academic emotions mediate the effect of academic buoyancy on these expectations and behaviours. Sample. A total of 845 Finnish students in the sixth grade of primary school. Methods. Self-report data for academic buoyancy and academic emotions in the autumn semester and learning-related expectations and behaviours in the spring semester were analysed using structural equation modelling, controlling for gender, grade point average, and previous levels of learning-related expectations and behaviours. Results. The findings showed that high academic buoyancy indirectly predicted lower avoidance behaviour, fewer failure expectations, and higher task-oriented planning via academic emotions. High academic buoyancy was related to high enjoyment and hope as well as low boredom and hopelessness, which further predicted low failure expectations. High hope and low boredom also predicted low avoidance behaviour and high hope was associated with high task-oriented planning. Conclusions. The findings suggest that academic buoyancy supports positive expectations and adaptive behaviours in learning situations through the regulation of emotions

Belowground plant allocation regulates rice methane emissions from degraded peat soils

Carbon-rich peat soils have been drained and used extensively for agriculture throughout human history, leading to significant losses of their soil carbon. One solution for rewetting degraded peat is wet crop cultivation. Crops such as rice, which can grow in water-saturated conditions, could enable agricultural production to be maintained whilst reducing CO$_{2}$ and N$_{2}$O emissions from peat. However, wet rice cultivation can release considerable methane (CH$_{4}$). Water table and soil management strategies may enhance rice yield and minimize CH$_{4}$ emissions, but they also influence plant biomass allocation strategies. It remains unclear how water and soil management influences rice allocation strategies and how changing plant allocation and associated traits, particularly belowground, influence CH$_{4}$-related processes. We examined belowground biomass (BGB), aboveground biomass (AGB), belowground:aboveground ratio (BGB:ABG), and a range of root traits (root length, root diameter, root volume, root area, and specific root length) under different soil and water treatments; and evaluated plant trait linkages to CH$_{4}$. Rice (Oryza sativa L.) was grown for six months in field mesocosms under high (saturated) or low water table treatments, and in either degraded peat soil or degraded peat covered with mineral soil. We found that BGB and BGB:AGB were lowest in water saturated conditions where mineral soil had been added to the peat, and highest in low-water table peat soils. Furthermore, CH$_{4}$ and BGB were positively related, with BGB explaining 60% of the variation in CH$_{4}$ but only under low water table conditions. Our results suggest that a mix of low water table and mineral soil addition could minimize belowground plant allocation in rice, which could further lower CH$_{4}$ likely because root-derived carbon is a key substrate for methanogenesis. Minimizing root allocation, in conjunction with water and soil management, could be explored as a strategy for lowering CH$_{4}$ emissions from wet rice cultivation in degraded peatlands

Immune-mediated loss of transgene expression from virally transduced brain cells is irreversible, mediated by IFNγ, perforin, and TNFα, and due to the elimination of transduced cells

The adaptive immune response to viral vectors reduces vector-mediated transgene expression from the brain. It is unknown, however, whether this loss is caused by functional downregulation of transgene expression or death of transduced cells. Herein, we demonstrate that during the elimination of transgene expression, the brain becomes infiltrated with CD4 and CD8 T cells and that these T cells are necessary for transgene elimination. Further, the loss of transgene-expressing brain cells fails to occur in the absence of IFNγ, perforin, and TNFα receptor. Two methods to induce severe immune suppression in immunized animals also fail to restitute transgene expression, demonstrating the irreversibility of this process. The need for cytotoxic molecules and the irreversibility of the reduction in transgene expression suggested to us that elimination of transduced cells is responsible for the loss of transgene expression. A new experimental paradigm that discriminates between downregulation of transgene expression and the elimination of transduced cells demonstrates that transduced cells are lost from the brain upon the induction of a specific antiviral immune response. We conclude that the anti-adenoviral immune response reduces transgene expression in the brain through loss of transduced cellsFil: Zirger, Jeffrey M.. Cedars Sinai Medical Center; Estados Unidos. University of California at Los Angeles. School of Medicine; Estados UnidosFil: Puntel, Mariana. University of California at Los Angeles. School of Medicine; Estados Unidos. Cedars Sinai Medical Center; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Bergeron, Josee. Cedars Sinai Medical Center; Estados Unidos. University of California at Los Angeles. School of Medicine; Estados UnidosFil: Wibowo, Mia. University of California at Los Angeles. School of Medicine; Estados Unidos. Cedars Sinai Medical Center; Estados UnidosFil: Moridzadeh, Rameen. University of California at Los Angeles. School of Medicine; Estados Unidos. Cedars Sinai Medical Center; Estados UnidosFil: Bondale, Niyati. Cedars Sinai Medical Center; Estados Unidos. University of California at Los Angeles. School of Medicine; Estados UnidosFil: Barcia, Carlos. Cedars Sinai Medical Center; Estados Unidos. University of California at Los Angeles. School of Medicine; Estados UnidosFil: Kroeger, Kurt M.. University of California at Los Angeles. School of Medicine; Estados Unidos. Cedars Sinai Medical Center; Estados UnidosFil: Liu, Chunyan. University of California at Los Angeles. School of Medicine; Estados Unidos. Cedars Sinai Medical Center; Estados UnidosFil: Castro, Maria Graciela. University of California at Los Angeles. School of Medicine; Estados Unidos. Cedars Sinai Medical Center; Estados Unidos. University of Michigan; Estados UnidosFil: Lowenstein, Pedro R.. Cedars Sinai Medical Center; Estados Unidos. University of California at Los Angeles. School of Medicine; Estados Unidos. University of Michigan; Estados Unido

Owner-Reported Clinical Signs and Management-Related Factors in Horses Radiographed for Intestinal Sand Accumulation

Clinical problems related to intestinal sand accumulation in horses are common in certain geographic areas, but the clinical signs appear nonspecific and the course of the accumulation remains somewhat obscure. This study examined the association between the presence and size of intestinal sand accumulations and owner-reported clinical signs, management, and feeding practices, as well as behavioral patterns in horses with radiographic diagnosis of sand accumulation. Owners of the horses filled in an online questionnaire. A total of 447 responses met the inclusion criteria. The size of the sand accumulation detected in the radiographs was not significantly associated with the age, body condition score, sex, or use of the horses. Horses reported to have expressed colic had significantly larger sand accumulations than those without this sign, and a similar association was detected in horses with poor performance. The highest odds ratio for sand accumulation was for the combination of colic and poor performance, followed by colic combined with diarrhea/loose feces or hyperesthesia to touch of the abdominal wall. Larger sand accumulations were detected in greedy horses that eat all their roughage, whereas dominant position in group hierarchy was associated with less sand. The possibility of abdominal sand accumulation should be considered as one of the differentials in horses with multiple owner-reported clinical signs such as colic, poor performance, diarrhea, and hyperesthesia to touch of the abdomen. (C) 2019 The Authors. Published by Elsevier Inc.Peer reviewe