Browsing by Subject "RETENTION"

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  • Kotze, D. Johan; Kuoppamaki, Kirsi; Niemikapee, Juhamatti; Mesimaki, Marja; Vaurola, Ville; Lehvavirta, Susanna (2020)
    The proliferation of vegetated, or green roofs, warrant a revisit of the terminology used in order to efficiently, and without confusion, convey information among scientists, policy makers and practitioners. A Web of Science and Google Scholar search (from 1996 to 2018) showed a steady increase in green roof articles, reaching close to 300 per year in WOS and ca. 2500 in Google Scholar, with approximately 10-20%, and up to 40 % of all articles using the terms extensive and/or intensive, especially in recent years. We evaluated the use of these terms, including 'green roof, and 'intensive and extensive roof', found that they are used in confusing ways, and provide compelling evidence that there is a need for revising the terminology. Acknowledging that most, if not all, vegetated roofs are multifunctional, we propose a new classification system based on the roof's primary function(s) and vegetation, such as "stormwater meadow roof", "biodiversity meadow roof", "biodiversity forest roof", or even "multifunctional meadow roof". This new terminological sphere is not meant to be rigid, but should be allowed to evolve so that useful combinations survive the scrutiny of academia and practitioners, while less useful ones go extinct. A clear and standardized terminology will serve to avoid confusion, allow for generalizations and aid in the development of this rapidly-expanding field.
  • Lehtamo, Sanna; Juuti, Kalle; Inkinen, Janna; Lavonen, Jari (2018)
    Background: There is a lack of students enrolling in upper secondary school physics courses. In addition, many students discontinue the physics track, causing a lack of applicants for university-level science, technology, engineering and mathematics (STEM) programmes. The aim of this research was to determine if it is possible to find a connection between academic emotions in situ and physics track retention at the end of the first year of upper secondary school using phone-delivered experience sampling method. We applied experience sampling delivered by phone to one group of students in one school. The sample comprised 36 first-year upper secondary school students (median age 16) who enrolled in the last physics course of the first year. Students' academic emotions during science learning situations were measured using phones three times during each of four physics lessons. Results: The logistic regression analysis showed that lack of stress predicted retention in the physics track. Conclusions: Via questionnaires delivered by phone, it is possible to capture students' academic emotions in situ, information on which may help teachers to support students emotionally during their physics studies. In addition, reflecting their situational academic emotions, students could perhaps make better-informed decisions concerning their studies in STEM subjects.
  • JET Contributors; Ashikawa, N.; Heinola, K.; Ahlgren, T. (2020)
    Quantitative tritium inventory in dust particles from campaigns in the JET tokamak with the carbon wall (2007-2009) and the ITER-like wall (ILW 2011-2012) were determined by the liquid scintillation counter and the full combustion method. A feature of this full combustion method is that dust particles were covered by a tin (Sn) which reached 2100 K during combustion under oxygen flow. The specific tritium inventory for samples from JET with carbon and with metal walls was measured and found to be similar. However, the total tritium inventory in dust particles from the ILW experiment was significantly smaller in comparison to the carbon wall due to the lower amount of dust particles generated in the presence of metal walls.
  • Heikonen, Lauri; Pietarinen, Janne; Pyhältö, Kirsi; Toom, Auli; Soini, Tiina (2017)
    Teachers' capacity to learn intentionally and responsively in the classroom is particularly vulnerable during the first years in the profession. This study investigated the interrelations between early career teachers' turnover intentions, perceived inadequacy in teacher-student interaction, and sense of professional agency in the classroom. The survey data were collected from 284 in-service teachers with not more than 5 years of experience and analysed by structural equation modelling (SEM). The results showed that the negative relation between turnover intentions and early career teachers' sense of professional agency was completely mediated by perceived inadequacy in teacher-student interaction. The results indicate that experiences of insufficient abilities to solve pedagogically and socially challenging student situations have a crucial effect on early career teacher's capacity for adaptive reflection and active transformation of instruction.
  • Asikainen, Henna; Blomster, Jaanika; Virtanen, Viivi (2018)
    Teacher support is an important factor affecting academic and social integration into the university. However, studies have been very scarce concerning both students' and teachers' experiences of their relationship in higher education. The purpose of this study is to examine students' and teachers' experiences of communality and interaction as well as the support given by teachers in the academic community. A total of 68 teachers and 104 students participated in this study by answering both Likert-scale and an open-ended question. The results show wide variation in both students' and teachers' experiences. The experiences varied from descriptions of a good and functional communality to a gap between teachers and students or even hostile behaviour towards students. Five main categories emerged from the data: (1) functioning interaction and communality, (2) good quality contacts between students and teachers, (3) variable experiences of interaction and communality, (4) low quality interaction and communality, and (5) dysfunctional contacts between students and teachers. The results indicate that teachers experience the support given to students more positively than the students. In addition, the results concerning the open-ended question also indicated that teachers experience the communality and interaction between teachers and students more positively than the students. More attention should be given to the teacher-student relationship at the higher education level. In addition, general skills such as ability to interact with others and social behaviour should be emphasised to a greater degree when recruiting staff.
  • Matikainen, Niina; Burza, Maria Antonella; Romeo, Stefano; Hakkarainen, Antti; Adiels, Martin; Folkersen, Lasse; Eriksson, Per; Lundbom, Nina; Ehrenborg, Ewa; Orho-Melander, Marju; Taskinen, Marja-Riitta; Boren, Jan (2013)
  • NEO-RACo Study Grp (2018)
    Adverse events (AEs) are common during disease-modifying antirheumatic drug (DMARD) treatment, but their influence on treatment results is unclear. We studied AEs in relation to disease activity in early rheumatoid arthritis (RA). Ninety-nine patients started intensive treatment with three conventional synthetic DMARDs (csDMARDs) and oral prednisolone, and were randomized to a 6-month induction treatment with infliximab or placebo. All AEs during the first 12 months of treatment were recorded. We scored each AE based on severity (scale 1-4) and defined the burden of AEs as the sum of these scores. Patients were divided into tertiles according to the burden of AEs. As outcomes, we assessed 28-joint disease activity score (DAS28) levels and remission rates at 12 and 24 months. Three hundred thirty-one AEs in 99 patients were reported, and 27 (8%) were categorized as severe or serious. Mean burden of AEs per patient was 5.4 +/- 4.3. Seventy-nine AEs (24%) led to temporary (n = 52) or permanent (n = 27) csDMARD discontinuation. Of discontinuations, 1, 21, and 57 were detected in the first, second, and third tertiles, respectively. DAS28 remission rates decreased across tertiles at 12 months (94, 94, and 76%; p for linearity 0.029) and at 24 months (90, 86, and 70%; p for linearity 0.021). Mean DAS28 levels increased across tertiles at 12 months (1.5 +/- 1.0, 1.7 +/- 0.9, and 1.9 +/- 1.2; p for linearity 0.021) and at 24 months (1.4 +/- 0.8, 1.6 +/- 1.0, and 1.9 +/- 1.1; p for linearity 0.007). High burden of AEs is associated with higher disease activity and lower likelihood of remission in early RA.
  • Hodille, E. A.; Byggmästar, J.; Safi, E.; Nordlund, K. (2019)
    The sputtering and reflection properties of wurtzite beryllium oxide (BeO) subjected to deuterium (D) ions bombardment at 300 K with ion energy between 10 eV and 200 eV is studied by classical molecular dynamics. Cumulative irradiations of wurtzite BeO show a D concentration threshold above which an 'unphysical dramatic' sputtering is observed. From the cumulative irradiations, simulation cells with different D concentrations are used to run non-cumulative irradiations at different concentrations. Using a D concentration close to the experimentally determined saturation concentration (0.12 atomic fraction), the simulations are able to reproduce accurately the experimental sputtering yield of BeO materials. The processes driving the sputtering of beryllium (Be) and oxygen (O) atoms as molecules are subsequently determined. At low irradiation energy, between 10 eV and 80 eV, swift chemical sputtering (SCS) is dominant and produces mostly ODz molecules. At high energy, the sputtered molecules are mostly BexOy molecules (mainly BeO dimer). Four different processes are associated to the formation of such molecules: the physical sputtering of BeO dimer, the delayed SCS not involving D ions and the detachment-induced sputtering. The physical sputtering of BeO dimer can be delayed if the sputtering event implies two interactions with the incoming ion (first interaction in its way in the material, the other in its way out if it is backscattered). The detachment-induced sputtering is a characteristic feature of the 'dramatic' sputtering and is mainly observed when the concentration of D is close to the threshold leading to this sputtering regime.
  • Lindblom, O.; Ahlgren, T.; Heinola, K. (2021)
    Solute hydrogen can cause many damaging processes in the lattices of metals, such as deformation of the material, which can take place in large scales through blistering and embrittlement. Especially in nuclear fusion applications, the trapped hydrogen isotope Tritium in the reactor wall materials can pose a radiological safety hazard. Techniques for hydrogen removal from metals usually require high temperatures. However, an efficient low temperature method to remove hydrogen is the so-called isotope exchange mechanism, where one isotope is being removed from the material by replacing it by another isotope introduced in the material. The atomic scale exchange mechanism of isotope exchange has not yet been determined. In this study we use molecular dynamics simulations to provide an atomic-scale explanation to the processes related to hydrogen isotope exchange in bulk materials. The results show that the lattice mono-vacancies and small vacancy clusters, usually produced in irradiation experiments, exhibit isotope exchange at low temperatures. The isotope exchange process should also be seen in other hydrogen trapping defects with similar trapping properties as vacancies.
  • Stape, Thiago Henrique Scarabello; Tjäderhane, Leo; Abuna, Gabriel; Sinhoreti, Mário Alexandre Coelho; Martins, Luís Roberto Marcondes; Tezvergil-Mutluay, Arzu (2018)
    Objective. To determine whether bonding effectiveness and hybrid layer integrity on acid-etched dehydrated dentin would be comparable to the conventional wet-bonding technique through new dentin biomodification approaches using dimethyl sulfoxide (DMSO). Methods. Etched dentin surfaces from extracted sound molars were randomly bonded in wet or dry conditions (30 s air drying) with DMSO/ethanol or DMSO/H2O as pretreatments using a simplified (Scotchbond Universal Adhesive, 3M ESPE: SU) and a multi-step (Adper Scotchbond Multi-Purpose, 3M ESPE: SBMP) etch-and-rinse adhesives. Untreated dentin surfaces served as control. Bonded teeth (n=8) were stored in distilled water for 24 h and sectioned into resin-dentin beams (0.8 mm(2)) for microtensile bond strength test and quantitative interfacial nanoleakage analysis (n = 8) under SEM. Additional teeth (n = 2) were prepared for micropermeability assessment by CFLSM under simulated pulp ar pressure (20 cm H2O) using 5 mM fluorescein as a tracer. Microtensile data was analyzed by 3-way ANOVA followed by Tukey Test and nanoleakage by Kruskal-Wallis and Dunn-Bonferroni multiple comparison test (alpha = 0.05). Results. While dry-bonding of SBMP produced significantly lower bond strengths than wet-bonding (p Conclusion. DMSO pretreatments may be used as a new suitable strategy to improve bonding of water-based adhesives to demineralized air-dried dentin beyond conventional wetbonding. Less porous resin-dentin interfaces with higher bond strengths on air-dried etched dentin were achieved; nonetheless, overall efficiency varied according to DMSO's co-solvent and adhesive type. Clinical significance. DMSO pretreatments permit etched dentin to be air-dried before hybridization facilitating residual water removal and thus improving bonding effectiveness. This challenges the current paradigm of wet-bonding requirement for the etch-and-rinse approach creating new possibilities to enhance the clinical longevity of resin-dentin interfaces. (C) 2018 The Academy of Dental Materials. Published by Elsevier Inc. All rights reserved.
  • Ruuth, Maija; Äikäs, Lauri; Tigistu-Sahle, Feven; Käkelä, Reijo; Lindholm, Harri; Simonen, Piia; Kovanen, Petri T.; Gylling, Helena; Öörni, Katariina (2020)
    OBJECTIVE: Plant stanol ester supplementation (2-3 g plant stanols/d) reduces plasma LDL (low-density lipoprotein) cholesterol concentration by 9% to 12% and is, therefore, recommended as part of prevention and treatment of atherosclerotic cardiovascular disease. In addition to plasma LDL-cholesterol concentration, also qualitative properties of LDL particles can influence atherogenesis. However, the effect of plant stanol ester consumption on the proatherogenic properties of LDL has not been studied. APPROACH AND RESULTS: Study subjects (n=90) were randomized to consume either a plant stanol ester-enriched spread (3.0 g plant stanols/d) or the same spread without added plant stanol esters for 6 months. Blood samples were taken at baseline and after the intervention. The aggregation susceptibility of LDL particles was analyzed by inducing aggregation of isolated LDL and following aggregate formation. LDL lipidome was determined by mass spectrometry. Binding of serum lipoproteins to proteoglycans was measured using a microtiter well-based assay. LDL aggregation susceptibility was decreased in the plant stanol ester group, and the median aggregate size after incubation for 2 hours decreased from 1490 to 620 nm,P=0.001. Plant stanol ester-induced decrease in LDL aggregation was more extensive in participants having body mass index CONCLUSIONS: Consumption of plant stanol esters decreases the aggregation susceptibility of LDL particles by modifying LDL lipidome. The resulting improvement of LDL quality may be beneficial for cardiovascular health. REGISTRATION: URL: https://www.clinicaltrials.gov. Unique identifier: NCT01315964. GRAPHIC ABSTRACT: A graphic abstract is available for this article.
  • Das, Sudeep; Imlimthan, Surachet; Airaksinen, Anu; Sarparanta, Mirkka (Springer Nature Switzerland AG, 2021)
    Advances in Experimental Medicine and Biology
    In the recent years, progress in nanotechnology has significantly contributed to the development of novel pharmaceutical formulations to overcome the drawbacks of conventional treatments and improve the therapeutic outcome in many diseases, especially cancer. Nanoparticle vectors have demonstrated the potential to concomitantly deliver diagnostic and therapeutic payloads to diseased tissue. Due to their special physical and chemical properties, the characteristics and function of nanoparticles are tunable based on biological molecular targets and specific desired features (e.g., surface chemistry and diagnostic radioisotope labeling). Within the past decade, several theranostic nanoparticles have been developed as a multifunctional nanosystems which combine the diagnostic and therapeutic functionalities into a single drug delivery platform. Theranostic nanosystems can provide useful information on a real-time systemic distribution of the developed nanosystem and simultaneously transport the therapeutic payload. In general, the diagnostic functionality of theranostic nanoparticles can be achieved through labeling gamma-emitted radioactive isotopes on the surface of nanoparticles which facilitates noninvasive detection using nuclear molecular imaging techniques, such as positron emission tomography (PET) and single-photon emission computed tomography (SPECT), meanwhile, the therapeutic effect arises from the potent drug released from the nanoparticle. Moreover, some radioisotopes can concurrently emit both gamma radiation and high-energy particles (e.g., alpha, beta, and Auger electrons), prompting the use either alone for radiotheranostics or synergistically with chemotherapy. This chapter provides an overview of the fundamentals of radiochemistry and relevant radiolabeling strategies for theranostic nanosystem development as well as the methods for the preclinical evaluation of radiolabeled nanoparticles. Furthermore, preclinical case studies of recently developed theranostic nanosystems will be highlighted.
  • Sakrabani, Ruben; Kern, Juergen; Mankasingh, Utra; Zavalloni, Costanza; Zanchettin, Giulia; Bastos, Ana Catarina; Tammeorg, Priit; Jeffery, Simon; Glaser, Bruno; Verheijen, Frank G. A. (2017)
    Biochar research is extensive and there are many pot and laboratory studies carried out in Europe to investigate the mechanistic understanding that govern its impact on soil processes. A survey was conducted in order to find out how representative these studies under controlled experimental conditions are of actual environmental conditions in Europe and biomass availability and conversion technologies. The survey consisted of various key questions related to types of soil and biochar used, experimental conditions and effects of biochar additions on soil chemical, biological and physical properties. This representativeness study showed that soil texture and soil organic carbon contents used by researchers are well reflected in the current biochar research in Europe (through comparison with published literature), but less so for soil pH and soil type. This study provides scope for future work to complement existing research findings, avoiding unnecessary repetitions and highlighting existing research gaps.
  • Hodille, Etienne; Byggmästar, Jesper; Safi, Elnaz; Nordlund, Kai (2020)
    The sputtering yield of beryllium oxide (BeO) by incident deuterium (D) ions, for energies from 10 eV to 200 eV, has been calculated for temperatures between 300 K and 800 K using classical molecular dynamics. First, cumulative irradiations are carried out to build up a concentration of D in the material, equal to the experimentally measured concentration, that varies from an atomic fraction of 0.12 (300 K-500 K) to 0.02 ( 800 K). After building up the concentration of D, noncumulative irradiations are carried out to estimate the sputtering yields of BeO. For all incident energies, the sputtering yield peaks at 500 K, being closely related to the decrease of the concentration of D above this temperature. At 10 eV, the concentration of D on the surface drives the temperature dependence, while above 30 eV, it is the amount of surface damage created during the cumulative irradiation.
  • Valles, G.; Martin-Bragado, I.; Nordlund, K.; Lasa, A.; Björkas, C.; Safi, E.; Perlado, J. M.; Rivera, A. (2017)
    Recently, tungsten has been found to form a highly underdense nanostructured morphology ("W fuzz") when bombarded by an intense flux of He ions, but only in the temperature window 900-2000 K. Using object kinetic Monte Carlo simulations (pseudo-3D simulations) parameterized from first principles, we show that this temperature dependence can be understood based on He and point defect clustering, cluster growth, and detrapping reactions. At low temperatures (2300 K), all He is detrapped from clusters, preventing the formation of the large clusters that lead to fuzz growth in the intermediate temperature range. (C) 2017 Elsevier B.V. All rights reserved.
  • Almen, Anna-Karin; Tamelander, Tobias (2020)
    Global warming is causing changes in the food web structure and seasonal plankton dynamics. The Baltic Sea is one of the fastest-warming sea areas and warming consequently affects the timing and magnitude of phytoplankton blooms. Based on available Chlorophyll a data from nine years between 1979 and 2018, from the entrance to the Gulf of Finland, we studied the timing of the phytoplankton spring bloom in relation to spring seawater temperature. We found the peak of the bloom to occur earlier in years with higher spring seawater temperature. In warmer years, there was also a shorter time lag between phytoplankton and zooplankton biomass peaks. In addition, it seems as the spring bloom total biomass has decreased with time, with more extensive summer blooms during later years, in line with the general trend observed in the Baltic Sea. The spring bloom has traditionally been considered the most important part of the season, but we argue that the whole growth season should be investigated since summer blooms appear to increase with warming.
  • Manninen, Suvi; Lankinen, Maria; Erkkilä, Arja; Nguyen, Su Duy; Ruuth, Maija; de Mello, Vanessa; Öörni, Katariina; Schwab, Ursula (2019)
    Background and aims: Omega-3 fatty acids are known to have several cardioprotective effects. Our aim was to investigate the effects of intakes of fish and Camelina sativa oil (CSO), rich in alpha-linolenic acid, on the atherogenic and anti-atherogenic functions of LDL and HDL particles. Methods: Altogether, 88 volunteers with impaired glucose metabolism were randomly assigned to CSO (10 g of alpha-linolenic acid/day), fatty fish (4 fish meals/week), lean fish (4 fish meals/week) or control group for 12 weeks. 79 subjects completed the study. The binding of lipoproteins to aortic proteoglycans, LDL aggregation and activation of endothelial cells by LDL and cholesterol efflux capacity of HDL were determined in vitro. Results: Intake of CSO decreased the binding of lipoproteins to aortic proteoglycans in a non-normalized model (p = 0.006). After normalizing with serum concentrations of non-HDL cholesterol, apolipoprotein B (apoB) or LDL cholesterol, which decreased in the CSO group, the change was no longer statistically significant. In the fish groups, there were no changes in the binding of lipoproteins to proteoglycans. Regarding other lipoprotein functions, there were no changes in any of the groups. Conclusions: Intake of CSO decreases the binding of lipoproteins to aortic proteoglycans by decreasing serum LDL cholesterol concentration, which suggests that the level of apoB-containing lipoproteins in the circulation is the main driver of lipoprotein retention within the arterial wall. Intake of fish or CSO has no effects on other lipoprotein functions.
  • Almeland, Stian Kreken; Lindford, Andrew; Sundhagen, Henriette Pisani; Hufthammer, Karl Ove; Strandenes, Eivind; Svendsen, Henrik Lovendahl; Guttormsen, Anne Berit; Hansson, Emma (2020)
    Background It has been demonstrated that medical students are capable of learning microsurgical techniques. We hypothesize that microsurgical training might give insight into the importance of delicate tissue handling and correct knot tying that could have a positive influence on macrosurgical skills. The primary aim of this study was to evaluate the effect of microsurgical training on macrosurgical suturing skills in novice medical students. Subjects and methods In 2018, 46 novice medical students were enrolled and randomized into two groups. The intervention group received both macro- and microsurgical training and the control group received only microsurgical training. Both groups underwent an assessment test that consisted of macrosurgical tasks of three simple interrupted sutures with a square knot and continuous three-stitch long over-and-over sutures. These tests were individually filmed and assessed using the University of Bergen suturing skills assessment tool (UBAT) and the Objective Structured Assessment of Technical Skill global rating scale (OSATS). Questionnaires regarding future career ambitions and attitudes towards plastic surgery were also completed both prior to and following the tests. Results The intervention group needed a longer time to complete the tasks than the control group (12.2 min vs. 9.6 min, p > 0.001), and scored lower on both the UBAT (5.6 vs. 9.0, p > 0.001) and the OSATS (11.1 vs. 13.1, p > 0.001) assessments. The microsurgery course tended to positively influence the students' attitudes towards a career in plastic surgery (p = 0.002). This study demonstrates poorer macrosurgical skills in the medical students group exposed to microsurgical training. The true effect of microsurgical training warrants further investigation. Level of evidence: Level I, diagnostic study.
  • Heponiemi, Tarja; Kouvonen, Anne; Virtanen, Marianna; Vanska, Jukka; Elovainio, Marko (2014)