92 research outputs found
Hygrothermal performance of highly insulated external walls subjected to indoor air exfiltration
The study comprises three laboratory tests in which typical Finnish highly insulated (HI) walls were exposed to concentrated leakages of indoor air under steady outdoor temperatures of 1–5°C. Airflows with a relative humidity of 50% and at rates of 1–3 L/min were directed close to the wooden frames inside the walls. The thermal resistance ratios between the exterior sheathing(s) and the whole wall (Γ) were 20%–22% and 1%–10% for the HI and baseline (BL) walls. The HI walls that presented Γ values of at least 20% were observed to be resistant to air exfiltration, and their durability was not affected by the addition of a gypsum sheathing outside the wooden frame or a more permeable vapor retarder. This is related to the negative linear correlation that exists between the moisture accumulation rate in wood-based material and the dew point depression (DPD) value. The developed approach, called the DPD method, shows that a significant degree of moisture accumulation does not occur even for DPD values of as low as −2°C if the exterior sheathing is vapor permeable. The airflow does not penetrate into the rigid mineral wool sheathing, which helps to avoid interstitial condensation. Regardless of thermal transmittance, the HI and BL walls with maximum Γ values of 1% were exposed to a high relative humidity and even interstitial condensation because the DPD values were often below −2°C. For these walls, the mold index analysis and visual observations confirmed the local risk for mold growth on the opposite side of the leakage point. In practice, long-term mold growth may be limited if the seasonal periods during which the outdoor temperature is 1–5°C last for a maximum of about 1 month every year.©The Author(s) 2022. https://creativecommons.org/licenses/by/4.0/This article is distributed under the terms of the Creative Commons Attribution 4.0 License (https://creativecommons.org/licenses/by/4.0/) which permits any use, reproduction and distribution of the work without further permission provided the original work is attributed as specified on the SAGE and Open Access page (https://us.sagepub.com/en-us/nam/open-access-at-sage).fi=vertaisarvioitu|en=peerReviewed
Strength of K-Type of Joint made of S700
Integration of slim floor systems into high strength steel (HSS) trusses with K-joints promotes sustainable construction due to the high strength-to-weight ratio and open space buildings adaptable for different uses. As current design standards such as EN 1993-1-8 inadequately supports the design of HSS truss joints, in this study, two welded K-type joints made of S700 were tested using a scaled-down dimensions and examined numerically by finite element (FE) models. The scaling factors used for determining the dimensions of the downscaled joint were verified by the validated FE models. The tests on two specimens with the different chord lengths were used to define the strength of the HSS joint: which was controlled by either the ultimate strength of the tension bracing or the buckling resistance of the compression bracing. Compared to the joint of the double grade steel S355J2/S420, the results pointed out that the limit load of HSS joint was 70% higher but the joint ductility was decreased by 25% when compared to the joint of double grade steel S355J2/S420. Due to the instability failure of the compression bracing, applying a larger safety factor for the limit load of S700 joint is necessary but additional parametric studies are needed to propose the equations for the joint limit load in design use.The authors are grateful Ruukki Construction Oy for providing the test specimens and for the Department of Mechanical Engineering for enhancing the specimens. The authors are also grateful for the technical team of the laboratory at the Department of Civil Engineering for preparing and performing the experiments
Generation of a human induced pluripotent stem cell line (LL008 1.4) from a familial Alzheimer's disease patient carrying a double KM670/671NL (Swedish) mutation in APP gene
A double mutation (KM670/671NL) in amyloid precursor protein gene (APP) is causative for familial Alzheimer's disease and has been shown to increase the total A beta burden. Here we report the generation and characterization of an iPSC line from a fAD patient carrying APP KM670/671NL. The generated iPSCs retained the mutation, expressed pluripotency markers, showed a normal karyotype and differentiated into all three germ layers. This iPSC line can be used, for example, in disease modeling and mechanistic studies.Peer reviewe
Physical Activity, Sleep, and Symptoms of Depression in Adults - Testing for Mediation
Purpose: Physical activity, sleep problems, and symptoms of depression contribute to overall well-being. The factors are reciprocally associated, but the nature of these associations remains unclear. The present study examined whether sleep problems mediated the association between physical activity and depressive symptoms. Methods: The eligible population (n = 3596) consisted of adults from the ongoing, population-based Cardiovascular Risk in Young Finns Study started in 1980. Participants' leisure-time physical activity was assessed with physical activity index (2007) and sleep problems with Jenkins' Sleep Questionnaire in 2007 and 2011. Depressive symptoms were measured using modified Beck Depression Inventory in 2007 and 2012, from which the items reflecting sleep problems were excluded. Mediation analyses, through which the associations between the variables were examined, were adjusted for sex and a set of health-related covariates assessed in 2007 and 2011. Results: Physical activity was associated with decreased levels of sleep problems and depressive symptoms (P 0.05). Conclusions: Physical activity's favorable contribution to depressive symptoms was mediated partly by sleep, but the mediation effect disappeared after adjusting for the previous depressive symptoms in adulthood.Peer reviewe
Sex-specific transcriptional and proteomic signatures in schizophrenia
It has remained unclear why schizophrenia typically manifests after adolescence and which neurobiological mechanisms are underlying the cascade leading to the actual onset of the illness. Here we show that the use of induced pluripotent stem cell-derived neurons of monozygotic twins from pairs discordant for schizophrenia enhances disease-specific signal by minimizing genetic heterogeneity. In proteomic and pathway analyses, clinical illness is associated especially with altered glycosaminoglycan, GABAergic synapse, sialylation, and purine metabolism pathways. Although only 12% of all 19,462 genes are expressed differentially between healthy males and females, up to 61% of the illness-related genes are sex specific. These results on sex-specific genes are replicated in another dataset. This implies that the pathophysiology differs between males and females, and may explain why symptoms appear after adolescence when the expression of many sex-specific genes change, and suggests the need for sex-specific treatments.Peer reviewe
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Creation of a library of induced pluripotent stem cells from Parkinsonian patients.
Induced pluripotent stem cells (iPSCs) are becoming an important source of pre-clinical models for research focusing on neurodegeneration. They offer the possibility for better understanding of common and divergent pathogenic mechanisms of brain diseases. Moreover, iPSCs provide a unique opportunity to develop personalized therapeutic strategies, as well as explore early pathogenic mechanisms, since they rely on the use of patients' own cells that are otherwise accessible only post-mortem, when neuronal death-related cellular pathways and processes are advanced and adaptive. Neurodegenerative diseases are in majority of unknown cause, but mutations in specific genes can lead to familial forms of these diseases. For example, mutations in the superoxide dismutase 1 gene lead to the motor neuron disease amyotrophic lateral sclerosis (ALS), while mutations in the SNCA gene encoding for alpha-synuclein protein lead to familial Parkinson's disease (PD). The generations of libraries of familial human ALS iPSC lines have been described, and the iPSCs rapidly became useful models for studying cell autonomous and non-cell autonomous mechanisms of the disease. Here we report the generation of a comprehensive library of iPSC lines of familial PD and an associated synucleinopathy, multiple system atrophy (MSA). In addition, we provide examples of relevant neural cell types these iPSC can be differentiated into, and which could be used to further explore early disease mechanisms. These human cellular models will be a valuable resource for identifying common and divergent mechanisms leading to neurodegeneration in PD and MSA
Sleepiness and stress among long-haul truck drivers : An educational intervention to promote safe and economic truck driving
Sleepiness and stress at the wheel are known to be common among professional drivers. Given the safety-sensitive nature of the job, it would be essential for neither of these conditions to reach levels compromising safe driving. The current field study examined the levels of sleepiness and stress at the wheel in a group of Finnish long-haul truck drivers, and the potential factors contributing to the sub-optimal levels of arousal. Over and above, the study examined whether driver alertness could be amended by short one-time alertness management training.
The results revealed that driver sleepiness reaches potentially risky levels, especially during the first night shift in the beginning of a shift spell. No clear evidence was found to support the idea that educating professional drivers on alertness management would be sufficient for mitigating their sleepiness on the road
Physical Activity, Sleep, and Symptoms of Depression in Adults-Testing for Mediation
Purpose: Physical activity, sleep problems, and symptoms of depression contribute to overall well-being. The factors are reciprocally associated, but the nature of these associations remains unclear. The present study examined whether sleep problems mediated the association between physical activity and depressive symptoms. Methods: The eligible population (n = 3596) consisted of adults from the ongoing, population-based Cardiovascular Risk in Young Finns Study started in 1980. Participants' leisure-time physical activity was assessed with physical activity index (2007) and sleep problems with Jenkins' Sleep Questionnaire in 2007 and 2011. Depressive symptoms were measured using modified Beck Depression Inventory in 2007 and 2012, from which the items reflecting sleep problems were excluded. Mediation analyses, through which the associations between the variables were examined, were adjusted for sex and a set of health-related covariates assessed in 2007 and 2011. Results: Physical activity was associated with decreased levels of sleep problems and depressive symptoms (P 0.05). Conclusions: Physical activity's favorable contribution to depressive symptoms was mediated partly by sleep, but the mediation effect disappeared after adjusting for the previous depressive symptoms in adulthood.</p
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