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排序方式: 共有351条查询结果,搜索用时 31 毫秒
1.
A previous study showed that classical building-related symptoms (BRS) were related to indoor dust and microbial toxicity via boar sperm motility assay, a sensitive method for measuring mitochondrial toxicity. In this cross-sectional study, we analyzed whether teachers’ most common work-related non-literature-known BRS (nBRS) were also associated with dust or microbial toxicity. Teachers from 15 schools in Finland completed a questionnaire evaluating 20 nBRS including general, eye, respiratory, hearing, sleep, and mental symptoms. Boar sperm motility assay was used to measure the toxicity of extracts from wiped dust and microbial fallout samples collected from teachers’ classrooms. 231 teachers answered a questionnaire and their classroom toxicity data were recorded. A negative binomial mixed model showed that teachers’ work-related nBRS were 2.9-fold (95% CI: 1.2-7.3) higher in classrooms with highly toxic dust samples compared to classrooms with non-toxic dust samples (p = 0.024). The RR of work-related nBRS was 1.8 (95% CI: 1.1-2.9) for toxic microbial samples (p = 0.022). Teachers’ BRS appeared to be broader than reported in the literature, and the work-related nBRS were associated with toxic dusts and microbes in classrooms. 相似文献
2.
Iqra Jabeen Asma Ejaz Adeel Akram Yasar Amin Jonathan Loo Hannu Tenhunen 《国际射频与微波计算机辅助工程杂志》2019,29(11)
A miniaturized, polarization insensitive, and fully passive chipless radio frequency identification tag is proposed in this research article. The realized tag is based on slotted elliptical structures in a nested loop fashion with identical lengths and widths of slot resonators. Alteration of data sequence is accomplished by addition and elimination of nested resonators in the geometric structure. The tag is capable to encode 10 bits of data and covers spectral range from 3.6 to 15.6 GHz. The formulated structure demonstrates polarization insensitive characteristic. The data encoding structure is analyzed and optimized for different substrates that are, Rogers RT/duroid/5880, Rogers RT/duroid/5870, and Taconic TLX‐0 over the miniaturized footprint of 22.8 × 16 mm2. The presented tag is robust, novel, compact, and flexible exhibiting a stable response to impinging electromagnetic waves at various angles of incidence. 相似文献
3.
Leiviskä T Nurmesniemi H Pöykiö R Rämö J Kuokkanen T Pellinen J 《Water research》2008,42(14):3952-3960
Pulp and paper mill wastewater was characterizated, before (influent) and after (effluent) biological wastewater treatment based on an activated sludge process, by microfiltration (8, 3, 0.45 and 0.22mum) and ultrafiltration (100, 50, 30 and 3kDa) of the wastewater samples into different size fractions. Various parameters were measured on each fraction: molecular weight distribution (MWD) using high performance size exclusion chromatography (HPSEC), total organic carbon (TOC), biochemical oxygen demand (BOD), chemical oxygen demand (COD), total phosphorus (Tot-P), phosphate phosphorus (PO(4)-P), electrical conductivity, pH, turbidity, charge quantity and zeta potential. The MWD, TOC and COD(Cr) results indicated that the majority of the material present in both the influent and effluent was in the medium molecular weight (MW) range (i.e. MW<10kDa) with three main MW sub-fractions. There were no significant differences in the range of the MWD between the influent and effluent samples. The magnitude of the MWD in the effluent was about one half that in the influent, the greatest reduction being in the 6kDa fraction. The 3kDa fractions of both the influent and effluent showed a considerable increase in BOD(7), probably due to the removal of compounds harmful to bacteria in 3kDa ultrafiltration. Influent turbidity decreased considerably in microfiltration (8-0.22mum). As the turbidity was removed by 0.22mum filtration, the anionic charge quantity started to decrease. Particles in the influent and effluent contained 19-29% and 14-20% of the total phosphorus, respectively. The major phosphorus fraction was in the form of soluble phosphate. 相似文献
4.
Hannu Nurmi 《控制论与系统》2013,44(2):35-50
Abstract This paper is an attempt to present an overview of the various meanings in which the concept of model is being employed in scientific literature. Particular emphasis is laid upon systems models and their characteristic features from the viewpoint of social science applications. The criteria of models in the pursuit of such classic goals as explanation and prediction are discussed. It turns out that the criteria of goodness of models should be different in explanation, prediction and action (or policy-making). It is argued that the organizational aspects of models deserve a careful attention because much of what is known about social reality is related to organization. Furthermore, most of what can be done about social reality is concerned with the component coupling structure of systems. Some illustrations from the social science literature are discussed in order to support the arguments of the paper. 相似文献
5.
采用三步分离法,其中第一步用水,第二步用乙酸铵,第三步用盐酸,提取纸浆发电厂生物质飞灰和底灰的组分,以评估这些残渣的浸出行为。除了Mo、S、Na以及那些浓度低于检测范围的元素外,在这两种灰份中,对于其他元素这三种浸出剂的浸出能力从弱到强的顺序为:水、乙酸铵和盐酸。采用三步分离法处理的废渣中元素浓度比前期用BCR连续提取法得到的低。 相似文献
6.
Hannu Linkola 《Landscape Research》2015,40(8):939-954
AbstractIn 2010, the Finnish Ministry of the Environment launched a re-evaluation and revision of the 1993 inventory of Nationally Valuable Landscape Areas (NVLAs). While the inventory works for implementation of the National Land Use Guidelines, it also showcases the use of landscapes in Finnish national heritage policy. Based on critical readings of three influential Finnish administrative landscape policy reports, I claim that NVLAs, as tools of heritage policy, are based on the approaches and methodologies that have supported Finland’s development into a modern nation state by providing tools for intellectual governance of the national past and territory. Rather than meeting the diversity of landscape conceptions, as defined in the European Landscape Convention, the NVLAs run a risk of being in conflict with citizens and actors that do not share the administrative assumption of landscapes as public containers of national heritage. 相似文献
7.
Atmospheric circulation patterns influencing variations in organic carbon fluxes in the River Oulujoki,Finland 下载免费PDF全文
Hannu Marttila Masoud Irannezhad Jaakko Saukkoriipi Bjørn Kløve 《Water and Environment Journal》2015,29(4):474-481
Atmospheric circulation generally influences regional climate variability and thereby controls catchment hydrology and consequently transport of elements in natural riverine systems. This study examined dependencies between total organic carbon (TOC) variability in the River Oulujoki (Finland) during 1963–2011 and prominent atmospheric circulation patterns (ACPs), which manifest natural climatic conditions over Finland and control hydrological processes in the river catchment. North Atlantic Oscillation, Scandinavia, East Atlantic and East Atlantic/West Russia patterns were statistically significant ACPs affecting variations in TOC export at River Oulujoki lower basin area. In the River Oulujoki, TOC export was largely controlled by changes in TOC fluxes generated from tributaries of river and near areas to its main channel. Besides, runoff from Lake Oulujärvi slightly influenced TOC export variability in the River Oulujoki. Understanding such responses of TOC fluxes to ACPs is a useful tool for sustainable water resources planning and management on regional and local scales. 相似文献
8.
Sami Myllymaa Emilia Kaivosoja Katja Myllymaa Tarvo Sillat Hannu Korhonen Reijo Lappalainen Yrj? T. Konttinen 《Journal of materials science. Materials in medicine》2010,21(1):329-341
It was hypothesized that human mesenchymal stromal cell (hMSC) can be guided by patterned and plain amorphous diamond (AD),
titanium (Ti), tantalum (Ta) and chromium (Cr) coatings, produced on silicon wafer using physical vapour deposition and photolithography.
At 7.5 h hMSCs density was 3.0–3.5× higher (P < 0.0003, except Ti) and cells were smaller (68 vs. 102 μm, P 0.000006–0.02) on patterns than on silicon background. HMSC-covered surface of the background silicon was lower on Ti than
AD patterns (P = 0.015), but at 5 days this had reversed (P = 0.006). At 7.5 h focal vinculin adhesions and actin cytoskeleton were outgoing from pattern edges so cells assumed geometric
square shapes. Patterns allowed induced osteogenesis, but less effectively than plain surfaces, except for AD, which could
be used to avoid osseointegration. All these biomaterial patterns exert direct early, intermediate and late guidance on hMSCs
and osteogenic differentiation, but indirect interactions exist with cells on silicon background. 相似文献
9.
Heponiemi Tarja; Kouvonen Anne; V?nsk? Jukka; Halila Hannu; Sinervo Timo; Kivim?ki Mika; Elovainio Marko 《Canadian Metallurgical Quarterly》2009,14(4):365
The present study examined whether job control moderated the association between stress indicators (distress and sleeping problems) and intentions to change profession among 2,650 Finnish physicians. Ordinal logistic regression analysis was applied. The authors found that high levels of distress and sleeping problems were associated with higher levels of intentions to change profession, whereas high job control was associated with lower levels of intentions to change profession even after adjusting for the effects of gender, age, and employment sector. In addition, high job control was able to mitigate the positive association that distress and sleeping problems had with intentions to change profession. Our findings highlight the importance of offering more job control to physicians to prevent unnecessary physician turnover. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
10.
Olli Dahl Hannu Nurmesniemi Risto Pöykiö Gary Watkins 《Fuel Processing Technology》2009,90(7-8):871-878
In this study, the physical and chemical properties of bottom ash and fly ash originating from the co-combustion of biomass-derived fuels (i.e. wood chips, sawdust, bark, and peat) from a 32 MW fluidized bed boiler at a municipal district heating plant were investigated. Silicate minerals were predominant in the bottom ash and calcium minerals in the fly ash, with most of the inorganic nutrients and heavy metals being enriched in the fly ash. The enrichment factors for heavy metals in the fly ash varied between 0.2 for silicon and 16.3 for lead, and for plant nutrients, between 1.5 for phosphorous and 108 for potassium. However, all heavy metal concentrations in both the bottom ash and fly ash were significantly lower than the current Finnish limit for maximum allowable heavy metal concentrations for forest fertilizers, which came into force in March 2007. According to the particle size distribution, the mass loadings of heavy metals in the fly ash were more than 90% contributed by the smallest particle size fraction lower than 0.074 mm. In the bottom ash, between 83.6 and 91.9% of the mass loadings of heavy metals were contributed by the particle size fraction between 0.5 and 2.0 mm. 相似文献