149 research outputs found
Methodology for evaluating the safety level of current accepted design solutions for limiting fire spread between buildings
External fire spread between buildings is internationally considered as a major concern for buildings in dense urban environments. While design guidelines differ between countries, the fundamental methods currently used for limiting the risk of fire spread between buildings are generally limited to specifying the minimum required separation distance for a given unprotected façade area, or conversely, limiting the maximum allowable unprotected façade area for a given separation distance. The safety level associated with the current design guidelines is however unknown, making the implementation of innovative, safer and more cost-effective design solutions difficult. In order to assess the safety target implicitly incorporated in currently accepted design solutions, a methodology is developed for evaluating the annual probability of reaching unacceptable radiation intensities at the opposite façade. As a case study, the methodology is applied to a design which is in agreement with the current UK requirements specified in BR 187. This case study exposes inconsistencies in the current design guidelines, indicating the need for developing explicit safety targets
Effect of site of lactate infusion on regional lactate exchange in pigs
Background The rate of extra-hepatic lactate production and the route of influx of lactate to the liver may influence both hepatic and extra-hepatic lactate exchange. We assessed the dose-response of hepatic and extra-hepatic lactate exchange during portal and central venous lactate infusion. Methods Eighteen pigs randomly received either portal (n=5) or central venous (n=7) lactate infusion or saline (n=6). Sodium lactate was infused at 33, 66, 99, and 133 µmol kg−1 min−1 for 20 min each. Systemic and regional abdominal blood flows and plasma lactate were measured at 20 min intervals until 1 h post-infusion, and regional lactate exchange was calculated (area under lactate uptake-time curve). Results Total hepatic lactate uptake [median (95% confidence interval)] during the experimental protocol (140 min) was higher during portal [8198 (5487-12 798) µmol kg−1] than during central venous lactate infusion [4530 (3903-5514) µmol kg−1, P<0.05]. At a similar hepatic lactate delivery (∼400 µmol kg−1 min−1), hepatic lactate uptake [mean and standard deviation (sd)] was higher during portal [118 (sd 55) µmol kg−1 min−1] than during central venous lactate infusion [44 (12) µmol kg−1 min−1, P<0.05]. Time courses of arterial lactate concentrations and lactate uptake at other measured regions were similar in both groups. Conclusions Higher hepatic lactate uptake during portal compared with central venous lactate infusion at a similar total hepatic lactate influx underlines the role of portal vein lactate concentration in total hepatic lactate uptake capacity. Arterial lactate concentration does not depend on the site of lactate infusion. At higher arterial lactate concentrations, all regions participated in lactate uptak
Enhancement of adhesion and promotion of osteogenic differentiation of human adipose stem cells by poled electroactive poly(vinylidene fluoride)
Poly(vinylidene fluoride) (PVDF) is a biocompatible material with excellent electroactive properties. Non-electroactive α-PVDF and electroactive β-PVDF were used to investigate the substrate polarization and polarity influence on the focal adhesion size and number as well as on human adipose stem cells (hASCs) differentiation. hASCs were cultured on different PVDF surfaces adsorbed with fibronectin and focal adhesion size and number, total adhesion area, cell size, cell aspect ratio and focal adhesion density were estimated using cells expressing EGFP-vinculin. Osteogenic differentiation was also determined using a quantitative alkaline phosphatase assay. The surface charge of the poled PVDF films (positive or negative) influenced the hydrophobicity of the samples, leading to variations in the conformation of adsorbed extracellular matrix (ECM) proteins, which ultimately modulated the stem cell adhesion on the films and induced their osteogenic differentiation.The study was supported financially by the Academy of Finland (136288,
140978 and 256931), the Sigrid Jusélius Foundation, the Pirkanmaa Hospital District and the
Finnish Funding Agency for Technology and Innovation (TEKES). This study was also
supported by FEDER through the COMPETE Program, by the Portuguese Foundation for
Science and Technology (FCT) in the framework of the Strategic Project PEST- C/FIS/UI607/2011 and by projects NANO/NMed-SD/0156/2007 and PTDC/CTM
NAN/112574/2009. The autors also thank the project Matepro – Optimizing Materials and
Processes”, ref. NORTE-07-0124-FEDER-000037”, co-funded by the “Programa Operacional
Regional do Norte” (ON.2 – O Novo Norte), under the “Quadro de Referência Estratégico
Nacional” (QREN), through the “Fundo Europeu de Desenvolvimento Regional” (FEDER). V.S.
and C.R. thank the FCT for the SFRH/BPD/63148/2009 and SFRH/BPD/90870/2012 grants,
respectively
The influence of learner characteristics on degree and type of participation in a CSCL environment
Computer-Supported Collaborative Learning (CSCL) is often presented as a promising learning method. However, it is also facing some new challenges. Apart from answering the question of whether or not working with CSCL generates satisfying learning outcomes, it is important to determine whether or not all participants profit from collaboration, with the computer as a means of communication. This paper describes the implementation and effects of an experimental program in 5 classes with a total of 120 students in elementary education who, in groups of four, engaged in Knowledge Forum discussion tasks on the subject of healthy eating. The study explores whether or not differences occur in the participation of students who differ in gender, sociocultural background and ability, and whether or not computer skills, computer attitudes, comprehensive reading scores and popularity with classmates are related to student participation. Students’ participation in this CSCL environment appears to be dependent on a number of learner characteristics. Girls contribute more words to the discussions than boys do and are more dependent on their computer skills in this production. Students who are good at comprehensive reading also contribute more words. Popularity among classmates appears to influence the degree of participation further. We also found indications that students with immigrant parents write fewer contributions than those whose parents are not immigrants
Recombinant family 3 carbohydrate-binding module as a new additive for enhanced enzymatic saccharification of whole slurry from autohydrolyzed eucalyptus globulus wood
By-products resulting from lignocellulosics pretreatment affect the digestibility of resulting whole slurries, but this can be minimized by additives supplementation. In this work, a family 3 carbohydrate-binding module (CBM3), recombinantly produced from Escherichia coli, was used as additive in the enzymatic hydrolysis of the whole slurry from autohydrolyzed Eucalyptus globulus wood (EGW). At the higher dosage used (30 mg/gsolids), CBM3 led to an increase in glucose yield from 75 to 89%. A similar result was obtained for bovine serum albumin (BSA) (11% increase), which has a well-documented additive effect. CBM3 had no effect on the non-productive binding of enzymes, since it could not bind to EGW lignin, while it rapidly bound to cellulose, as shown by fluorescence microscopy. CBM3 is a valid additive for enhanced lignocellulosic saccharification and a valuable alternative to costly additives (e.g. polyethylene glycol) as it can be affordably produced from heterologous bacterium, thus contributing to more cost-efficient biomass valorization bioprocesses.This work was developed under the strategic funding of UID/BIO/04469/2013 unit, COMPETE 2020 (POCI-01-0145-FEDER-006684) and BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020—Programa Operacional Regional do Norte. The research leading to the reported results has received funding from Fundação para a Ciência e a Tecnologia (FCT) through the project MultiBiorefinery (POCI-01–0145-FEDER-016403) and through grants to C. Oliveira (SFRH/BPD/110640/2015) and D. Gomes (SFRH/BD/88623/2012).info:eu-repo/semantics/publishedVersio
Työasioiden vatvominen vapaa-ajalla yksilön kokemuksena
Tiivistelmä. Tutkimuksen tarkoituksena on tarkastella työasioiden vatvomista vapaa-ajalla yksilön kokemuksena. Tässä tutkimuksessa vatvomisella (engl. “rumination”) tarkoitetaan työhön liittyvien asioiden toistuvaa ajattelua vapaa-ajalla. Tutkimme, mitä asioita yksilö vatvoo, miten ne koetaan ja millaisia vaikutuksia vatvomisella nähdään olevan. Lisäksi tutkimme, miten haitallista vatvomista voidaan ehkäistä yksilön ja organisaation toimesta. Tutkimuksen teoreettisena viitekehyksenä käytettiin Cropleyn ja Zijlstran (2011) teoriaa vatvomisesta. Tutkimusaineisto kerättiin kesällä 2019 haastatellen kuutta ICT-alan asiantuntijaa. Aineistonanalyysimenetelmänä käytettiin teoriaohjaavaa sisällönanalyysiä.
Tulosten perusteella vatvominen koettiin positiivisena, negatiivisena tai neutraalina riippuen siitä, mitä työhön liittyviä asioita vatvottiin. Positiivisena koettu vatvominen liittyi esimerkiksi innostaviin työtehtäviin ja ongelmanratkaisuun, jolloin myös sen vaikutukset nähtiin pitkälti positiivisina. Negatiivisena koettu vatvominen liittyi muun muassa keskeneräisiin työtehtäviin, liialliseen työkuormaan ja organisaatiokulttuurin piirteisiin. Tämä vaikutti heikentävästi unenlaatuun ja keskittymiskykyyn sekä aiheutti uupumusta. Vatvomisen neutraalissa kokemuksessa vatvominen nähtiin luonnollisena osana työelämää ja omaa identiteettiä. Merkittävinä tekijöinä vatvomisen ehkäisyn kannalta näyttäytyivät esimies-alaissuhde, organisaation yhteiset käytänteet sekä vapaa-ajan aktiviteetit.
Tutkimus tarjoaa tärkeää tietoa vatvomisen kokemuksesta ja mahdollisista keinoista haitallisen vatvomisen ehkäisyyn. Tutkimuksen tuloksia voidaan hyödyntää organisaatioiden käytäntöjen ja prosessien kehittämisen tukena haitallisen vatvomisen vähentämiseksi.Employee’s experiences of work-related rumination. Abstract. The aim of this study is to examine employee’s views and experiences about work-related rumination. Rumination is conceptualized as repetitive thinking of work-related affairs during off-job time. This study explores how rumination is conceived and how it affects the individual. This research also investigates how to prevent negative rumination in individual and organizational levels.
The theoretical framework of this study was Cropley and Zijlstra’s (2011) theory of work-related rumination. The research was conducted using a qualitative approach and the data consisted of six specialists working in a Finnish ICT-company. The data was gathered using interviews and analysed with content analysis during summer 2019.
The results show that depending on the subject of the work-related rumination it was experienced as positive, negative or neutral. Positive rumination was connected to inspiring tasks and problem solving at work. Negative rumination was linked to unfinished tasks, high workload and aspects in organizational culture. This affected negatively to sleep quality and concentration and caused exhaustion. Neutral rumination was seen as a natural part of working life and one’s identity. The employer-employee relationship, shared practices in the organization and employee’s free time activities were remarkable for preventing negative rumination.
The results of the present study cannot be generalized. However, the study offers valuable insights into employee’s experiences about rumination and possible ways to prevent negative rumination. The results can be used to improve organizations’ processes and practices for minimalizing the negative aspects of rumination
Baseline concentrations of biliary PAH metabolites in perch (Perca fluviatilis) in the open Gulf of Finland and in two coastal areas
Female perch (Perca fluviatilis) were sampled annually in late summer from 2006 to 2009 from the open sea of the eastern Gulf of Finland off Haapasaari island to monitor baseline biliary PAH metabolite concentrations. In addition, two coastal locations were sampled in 2008. PAH metabolite concentrations were compared between the open sea and coastal samples and between the sampling years and examined in relation to the body characteristics of perch. Of the PAH metabolites, only 1-hydroxypyrene (1 -OH pyrene) was detected at quantifiable levels in the bile of nearly all perch individuals. There were some annual differences but no temporal trend in the concentration of biliary 1-OH pyrene in perch from Haapasaari. At the coastal locations, 1-OH pyrene concentrations in the bile of perch were significantly higher than in the open sea Haapasaari area, probably due to greater contamination of the coastal sites and differences in feeding behaviour. No correlations between the body characteristics of perch and 1 -OH pyrene concentrations were detected. It is concluded that PAH metabolites in the bile of fish could be measured in the Gulf of Finland to detect oil spills in the open sea, and the cost-effective total fluorescence method could be used in such monitoring programmes. (C) 2017 Elsevier B.V. All rights reserved.Peer reviewe
Genome sequencing and population genomic analyses provide insights into the adaptive landscape of silver birch
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Surface Modification of Bioresorbable Phosphate Glasses for Controlled Protein Adsorption
The traditional silicate bioactive glasses exhibit poor thermal processability, which inhibits fiber drawing or sintering into scaffolds. The composition of the silicate glasses has been modified to enable hot processing. However, the hot forming ability is generally at the expense of bioactivity. Metaphosphate glasses, on the other hand, possess excellent thermal processability, congruent dissolution, and a tailorable degradation rate. However, due to the layer-by-layer dissolution mechanism, cells do not attach to the material surface. Furthermore, the congruent dissolution leads to a low density of OH groups forming on the glass surface, limiting the adsorption of proteins. It is well regarded that the initial step of protein adsorption is critical as the cells interact with this protein layer, rather than the biomaterial itself. In this paper, we explore the possibility of improving protein adsorption on the surface of phosphate glasses through a variety of surface treatments, such as washing the glass surface in acidic (pH 5), neutral, and basic (pH 9) buffer solutions followed or not by a treatment with (3-aminopropyl)triethoxysilane (APTS). The impact of these surface treatments on the surface chemistry (contact angle, ζ-potential) and glass structure (FTIR) was assessed. In this manuscript, we demonstrate that understanding of the material surface chemistry enables to selectively improve the adsorption of albumin and fibronectin (used as model proteins). Furthermore, in this study, well-known silicate bioactive glasses (i.e., S53P4 and 13-93) were used as controls. While surface treatments clearly improved proteins adsorption on the surface of both silicate and phosphate glasses, it is of interest to note that protein adsorption on phosphate glasses was drastically improved to reach similar protein grafting ability to the silicate bioactive glasses. Overall, this study demonstrates that the limited cell/phosphate glass biological response can easily be overcome through deep understanding and control of the glass surface chemistry
Molecular dynamics simulations reveal how vinculin refolds partially unfolded talin rod helices to stabilize them against mechanical force
Vinculin binds to specific sites of mechanically unfolded talin rod domains to reinforce the coupling of the cell’s exterior to its force generation machinery. Force-dependent vinculin–talin complexation and dissociation was previously observed as contraction or extension of the unfolded talin domains respectively using magnetic tweezers. However, the structural mechanism underlying vinculin recognition of unfolded vinculin binding sites (VBSs) in talin remains unknown. Using molecular dynamics simulations, we demonstrate that a VBS dynamically refolds under force, and that vinculin can recognize and bind to partially unfolded VBS states. Vinculin binding enables refolding of the mechanically strained VBS and stabilizes its folded α-helical conformation, providing resistance against mechanical stress. Together, these results provide an understanding of a recognition mechanism of proteins unfolded by force and insight into the initial moments of how vinculin binds unfolded talin rod domains during the assembly of this mechanosensing meshwork
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