The effect of cleanliness control during installation work on the amount of accumulated dust in ducts of new HVAC installations

The aim of this study was to evaluate the amount of dust in supply air ducts in recently installed ventilation systems. The samples for the determination of dust accumulation were collected from supply air ducts in 18 new buildings that have been constructed according to two different cleanliness control levels classified as category P1 (low oil residues and protected against contaminations) and category P2, as defined in the Classification of Indoor Climate, Construction and Building Materials. In the ducts installed according to the requirements of cleanliness category P1 the mean amount of accumulated dust was 0.9 g/m2 (0.4-2.9 g/m2), and in the ducts installed according to the cleanliness category P2 it was 2.3 g/m2 (1.2-4.9 g/m2). A significant difference was found in the mean amounts of dust between ducts of categories P1 and P2 (P < 0.008). The cleanliness control procedure in category P1 proved to be a useful and effective tool for preventing dust accumulation in new air ducts during the construction process. Additionally, the ducts without residual oil had lower amounts of accumulated dust indicating that the demand for oil free components in the cleanliness classification is reasonable.     

Microbial contamination of indoor air due to leakages from crawl space: a field study

Mechanical exhaust ventilation system is typical in apartment buildings in Finland. In most buildings the base floor between the first floor apartments and crawl space is not air tight. As the apartments have lower pressure than the crawl space due to ventilation, contaminated air may flow from the crawl space to the apartments. The object of this study was to find out whether a potential air flow from crawl space has an influence on the indoor air quality. The results show that in most cases the concentration of fungal spores was clearly higher in the crawl space than inside the building. The size distribution of fungal spores depended on the fungal species. Correlation between the fungal spores in the crawl space and indoors varied with microbial species. Some species have sources inside the building, which confounds the possible relation between crawl pace and indoor concentrations. Some species, such as Acremonium, do not normally have a source indoors, but its concentration in the crawl space was elevated; our measurements showed also elevated concentrations of Acremonium in the air of the apartments. This consistent finding shows a clear linkage between fungal spores in the indoor air and crawl space. We conclude that a building with a crawl space and pressure difference over the base floor could be a potential risk for indoor air quality in the first floor apartments.     

High surface area nanostructured tubes prepared by dissolution of ALD-coated electrospun fibers

Novel nanostructured and high surface area tubular materials were produced combining electrospinning and atomic layer deposition processes with the removal of polymeric template via dissolution. The dissolution process changed the structure of the tube walls, and the smooth atomic layer deposition coating was transformed into a highly complex, coral-like structure. This material, which we have called “nanocoral,” has a relatively high surface area, 323 m² g⁻¹, due to the interconnected cavities formed after the removal of the template. This kind of material has important potential applications, for example, in the fields of catalysts and filtration.     

Nitrate, nitrite, and N-nitroso compounds in Finnish foods and the estimation of the dietary intakes

Summary An estimate of the dietary intakes of nitrite, nitrate andN-nitroso compounds is presented, based on the analytical data supplied by the Finnish Food Quality Control. Figures on the food consumption of the Finnish population, taken from a national dietary survey, and food consumption of 1768 children and adolescents over a 48-h recall period were used. The mean daily dietary nitrate intakes were estimated to be about 55 mg for the total population and for children and adolescents. The mean nitrite intakes were 1.88 mg for the total population and 1.07 mg for children and adolescents. The intake ofN-nitroso compounds (NDMA) was estimated to be 0.08 g for the total population and 0.02 g for children. Nitrates were found to originate mainly from vegetables (80%), nitrites from meat products (97%) and nitrosamines mostly from fish products and beer. A comparison of the estimate of dietary intake of nitrite with ADI values indicated that the nitrite intake of the total population was 23% and by children 39% of ADI. The average weight was approximately 60 kg for adults and 20 kg for children. When measured average weight (39 kg) was used, and the nitrite intake was found to be 28% of ADI. Nitrate intakes from food additives were 2.5% and 1.4% of the ADI value, respectively. When the total nitrate intake from various food sources was compared with the ADI (which is given only for food additives), the estimated nitrate intake of the total population was 25% and that of children 28% of the ADI value.

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Nitrat, Nitrit und N-nitroso-Verbindungen in der finnischen Nahrung

Zusammenfassung Die Einnahme von Nitrat, Nitrit undN-Nitroso-Verbindungen stützt sich auf die analytischen Werte der finnischen Lebensmittelkontrolle. Für die Schätzung der Nahrungsaufnahme der finnischen Bevölkerung benutzte man Resultate einer nationalen Nahrungsforschung und eines 48-Stunden-Befundes für 1768 Kinder und Jugendliche. Die durchschnittliche tägliche Einnahme von Nitrat schätzte man auf ungefähr 55 mg für die ganze Bevölkerung. Die durchschnittliche Einnahme von Nitrit betrug 1,88 mg für die ganze Bevölkerung und 1,07 mg für Kinder und Jugendliche. Die Einnahme vonN-Nitroso-Verbindungen (NDMA) schätzte man auf 0,08 g für die ganze Bevölkerung und 0,02 g für Kinder. Die hauptsächliche Nahrungsquelle der Nitrate war Gemüse (80%) und bei den Nitriten die Fleischwaren (97%). Nitrosamine stammten hauptsächlich aus Fischwaren und aus Bier. Als man die geschätzte Einnahme von Nitrit mit den ADI-Werten verglich, ergab sich, daß die Einnahme von Nitrit 23% (ganze Bevölkerung) und 39% (Kinder) des ADI-Wertes war. Als durchschnittliches Körpergewicht nahm man 60 kg für Erwachsene und 20 kg für Kinder an. Wenn man den Wert des gemessenen durchschnittlichen Körpergewichts (39 kg) für Kinder benutzte, war die Einnahme von Nitrit 28% des ADI-Wertes. Die Einnahme von Nitrat in Zusatzstoffen war 2,5% und entsprechend 1,4% des ADI-Wertes. Die Einnahme von Nitrat in der Nahrung schätzte man auf 25% (ganze Bevölkerung) und auf 28% (Kinder) des ADI-Wertes (gegeben nur für Nitrat als Zusatzstoffe).

     

Protecting probiotic bacteria by microencapsulation: challenges for industrial applications

The use of probiotic bacteria in novel foods to provide beneficial health effects is today of increasing interest in the food industry. The process stability of probiotics is, however, not always optimal. Microencapsulation technology can be used to maintain the viability of probiotic bacteria during food product processing and storage. Both true microcapsules with coating as well as microspheres where the bacteria are evenly spread in the coating material are discussed. It is important that encapsulation keeps the probiotics active through the gastrointestinal tract and releases them in their target organ. The survival of microencapsulated cells in simulated gastric conditions is therefore also reviewed. Polysaccharides like alginate, gellan, κ-carrageenan and starch are the most commonly used materials in microencapsulation of bifidobacteria and lactobacilli. Techniques commonly applied for probiotic microencapsulation are emulsion, extrusion, spray drying, and adhesion to starch. Bead stability can be improved by using different coating materials, e.g. chitosan. Future challenges in the field include recognition of new potent applications, selection of appropriate techniques, materials and bacterial strains, and minimizing the extra costs incurred by microencapsulation.     

Indoor aerosols: from personal exposure to risk assessment

Motivated by growing considerations of the scale, severity, and risks associated with human exposure to indoor particulate matter, this work reviewed existing literature to: (i) identify state‐of‐the‐art experimental techniques used for personal exposure assessment; (ii) compare exposure levels reported for domestic/school settings in different countries (excluding exposure to environmental tobacco smoke and particulate matter from biomass cooking in developing countries); (iii) assess the contribution of outdoor background vs indoor sources to personal exposure; and (iv) examine scientific understanding of the risks posed by personal exposure to indoor aerosols. Limited studies assessing integrated daily residential exposure to just one particle size fraction, ultrafine particles, show that the contribution of indoor sources ranged from 19% to 76%. This indicates a strong dependence on resident activities, source events and site specificity, and highlights the importance of indoor sources for total personal exposure. Further, it was assessed that 10–30% of the total burden of disease from particulate matter exposure was due to indoor‐generated particles, signifying that indoor environments are likely to be a dominant environmental factor affecting human health. However, due to challenges associated with conducting epidemiological assessments, the role of indoor‐generated particles has not been fully acknowledged, and improved exposure/risk assessment methods are still needed, together with a serious focus on exposure control.     

Bayesian Scale Space Analysis of Differences in Images

This article considers the detection of image features in different spatial scales. The main focus is on capturing the scale-dependent differences in a pair of noisy images, but the technique developed can also be applied to the analysis of single images. The approach proposed uses Bayesian statistical modeling and simulation-based inference, and it can be viewed as a further development of SiZer technology, originally designed for nonparametric curve fitting. Numerical examples include artificial test images and a preliminary analysis of a pair of Landsat images used in satellite-based forest inventory. This article has supplementary material online.     

Hormone-dependent changes in A and B forms of progesterone receptor

The influence of different estrogen and/or progesterone treatments on concentrations of A and B forms of progesterone receptor (PR-A and PR-B) in the different cell types of chick oviduct was studied. A semiquantitative immunohistochemical assay for cellular PR concentrations was developed using a computer-assisted image analysis system. The staining intensity of nuclear PR in the basal layer of epithelial cells, glandular, smooth muscle and mesothelial cells was analysed separately using two monoclonal antibodies, PR6 and PR22. The measured concentrations of PR varied between different cell types and from cell to cell. A significant decrease in PR concentration, as noted by a decrease in staining intensity, was observed in all cell types studied 2 or 6 h after a single injection of progesterone with or without simultaneous estrogen administration. The decrease was also verified with immunoblotting and an immunoenzymometric assay (IEMA) for chicken PR. After down-regulation the concentration of PR recovered to the control level within 48 h after progesterone or estrogen administration. Estrogen administration alone was observed to cause changes in the concentration of PR-A only, having little or no effect on PR-B concentration depending on the cell type studied. These findings indicate that estrogen and progesterone cause cell-specific changes not only to the total concentration of PR but also to the cellular ratio of PR-A and PR-B.     

Adhesion between paints and wooden substrates: effects of pre-treatments and weathering of wood

The effects on adhesion between paints and wooden substrates due to pre-weathering (delay in painting), treatments of wood during pre-weathering and the moisture content of substrates were monitored. The adhesion was studied by means of a torque test. Wooden panels were untreated, or treated with unpigmented, penetrating wood preservatives or treated with pigmented strain, and pre-weathered for various periods. The panels were then painted and subjected to further exposure. The adhesion of the paints was determined at two relative humidities. Pre-weathering of 12 weeks impaired the adhesion significantly when emulsion paints were used, and when the wood substrates were untreated or treated with the unpigmented treatments during the pre-weathering. When the substrates were protected with a pigmented stain prior to painting, a longer delay before painting could be accepted. Also, wood substrates with higher moisture contents reduced the adhesion of the emulsion paints.

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Resume On a étudié l'adhérence de la peinture à des planches de bois à l'aide essai de torsion, et on a mesuré certains effets du vieillisement (délai avant de de peindre), de l'application de produits de préservation ainsi que le taux d'humidité du bois. Les planches de bois utilisées étaient soit non-traitées, soit traitées à l'aide d'un produit de préservation non pigmenté ou d'une teinture colorée. Toutes ont été soumises à une période variable de pré-vieillissement puis elles ont été peintes. A suivi une deuxième période de vieillissement, l'adhérence des peintures aux surfaces boisées a été verifiée à deux niveaux différents d'humidité du bois. L'adhérence des peintures à émulsion a été plus affectée par le pré-vieillissement de 12 semaines lorsque le bois était soit non-traité, soit traité avec un produit non pigmenté. Les produits teintés ont assuré une meilleure protection du bois, ce qui permet des délais plus longs avant de peindre (pour une adhérence de la peinture au bois équivalente). Les taux élevés d'humidité du bois ont contribué à une réduction de l'adhérence des peintures à émulsion.