Architectural design has the potential to influence the microbiology of the built environment, with implications for human health and well-being, but the impact of design on the microbial ...biogeography of buildings remains poorly understood. In this study we combined microbiological data with information on the function, form, and organization of spaces from a classroom and office building to understand how design choices influence the biogeography of the built environment microbiome.
Sequencing of the bacterial 16S gene from dust samples revealed that indoor bacterial communities were extremely diverse, containing more than 32,750 OTUs (operational taxonomic units, 97% sequence similarity cutoff), but most communities were dominated by Proteobacteria, Firmicutes, and Deinococci. Architectural design characteristics related to space type, building arrangement, human use and movement, and ventilation source had a large influence on the structure of bacterial communities. Restrooms contained bacterial communities that were highly distinct from all other rooms, and spaces with high human occupant diversity and a high degree of connectedness to other spaces via ventilation or human movement contained a distinct set of bacterial taxa when compared to spaces with low occupant diversity and low connectedness. Within offices, the source of ventilation air had the greatest effect on bacterial community structure.
Our study indicates that humans have a guiding impact on the microbial biodiversity in buildings, both indirectly through the effects of architectural design on microbial community structure, and more directly through the effects of human occupancy and use patterns on the microbes found in different spaces and space types. The impact of design decisions in structuring the indoor microbiome offers the possibility to use ecological knowledge to shape our buildings in a way that will select for an indoor microbiome that promotes our health and well-being.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
•Thermal mass located near ventilation inlets lost more heat through NVM at night.•Automated NVM can improve energy efficiency, but also provides opportunity for error.•Periodic commissioning is ...recommended to ensure correct NVM function.
Summer temperature extremes are expected to increase during the next century. Integrating night ventilation of mass (NVM) strategies in new ‘smart’ buildings could increase resilience to warming temperatures and reduce reliance on mechanical cooling. However, designing and operating buildings with NVM is challenging due to the complexity of interacting variables and difficulty of accurately measuring and predicting them, particularly when using automated controls and sensors. In this study we evaluated NVM performance by monitoring two night-ventilated classrooms in a mixed-mode smart academic building during October 2014 and June–July 2016. We investigated whether NVM systems were operating as intended, altered operation as needed to match design intent, and compared NVM efficacy during incorrect and corrected operation. We calculated the amount of heat NVM removed from each room overnight and visualized gradients of heat removal across the mass surface. We found that incorrect building automation system (BAS) operation during June 2016 resulted in overuse of mechanical cooling, while corrected operation later in July reduced the number of hours mechanical cooling was required, although average outdoor temperatures were higher. Our results also showed greatest overnight reductions in mass surface temperatures in locations nearest to the air inlets on the exterior south-facing walls. This critical evaluation quantifies the agreement between NVM performance as modeled during the design phase and during post-occupancy operation several years after construction. We conclude that the observed performance gap may be addressed through periodic or continuous re-commissioning.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Humans can spend the majority of their time indoors, but little is known about the interactions between the human and built-environment microbiomes or the forces that drive microbial community ...assembly in the built environment. We sampled 16S rRNA genes from four different surface types throughout a university classroom to determine whether bacterial assemblages on each surface were best predicted by routine human interactions or by proximity to other surfaces within the classroom. We then analyzed our data with publicly-available datasets representing potential source environments.
Bacterial assemblages from the four surface types, as well as individual taxa, were indicative of different source pools related to the type of human contact each surface routinely encounters. Spatial proximity to other surfaces in the classroom did not predict community composition.
Our results indicate that human-associated microbial communities can be transferred to indoor surfaces following contact, and that such transmission is possible even when contact is indirect, but that proximity to other surfaces in the classroom does not influence community composition.
Background Architectural design has the potential to influence the microbiology of the built environment, with implications for human health and well-being, but the impact of design on the microbial ...biogeography of buildings remains poorly understood. In this study we combined microbiological data with information on the function, form, and organization of spaces from a classroom and office building to understand how design choices influence the biogeography of the built environment microbiome. Results Sequencing of the bacterial 16S gene from dust samples revealed that indoor bacterial communities were extremely diverse, containing more than 32,750 OTUs (operational taxonomic units, 97% sequence similarity cutoff), but most communities were dominated by Proteobacteria, Firmicutes, and Deinococci. Architectural design characteristics related to space type, building arrangement, human use and movement, and ventilation source had a large influence on the structure of bacterial communities. Restrooms contained bacterial communities that were highly distinct from all other rooms, and spaces with high human occupant diversity and a high degree of connectedness to other spaces via ventilation or human movement contained a distinct set of bacterial taxa when compared to spaces with low occupant diversity and low connectedness. Within offices, the source of ventilation air had the greatest effect on bacterial community structure. Conclusions Our study indicates that humans have a guiding impact on the microbial biodiversity in buildings, both indirectly through the effects of architectural design on microbial community structure, and more directly through the effects of human occupancy and use patterns on the microbes found in different spaces and space types. The impact of design decisions in structuring the indoor microbiome offers the possibility to use ecological knowledge to shape our buildings in a way that will select for an indoor microbiome that promotes our health and well-being.
Full text
Available for:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
BACKGROUND:Humans can spend the majority of their time indoors, but little is known about the interactions between the human and built-environment microbiomes or the forces that drive microbial ...community assembly in the built environment. We sampled 16S rRNA genes from four different surface types throughout a university classroom to determine whether bacterial assemblages on each surface were best predicted by routine human interactions or by proximity to other surfaces within the classroom. We then analyzed our data with publicly-available datasets representing potential source environments.RESULTS:Bacterial assemblages from the four surface types, as well as individual taxa, were indicative of different source pools related to the type of human contact each surface routinely encounters. Spatial proximity to other surfaces in the classroom did not predict community composition.CONCLUSIONS:Our results indicate that human-associated microbial communities can be transferred to indoor surfaces following contact, and that such transmission is possible even when contact is indirect, but that proximity to other surfaces in the classroom does not influence community composition.
The development is complete on a load to dissipate 2-MW continuous wave of RF power at frequencies above 100 GHz and transmitted in the HE 11 waveguide. A rotating launcher distributes the RF power ...inside the load and prevents excessive localized heating from constructive interference. The load design also minimizes reflected power. Two loads are currently in operation in Japan, and the performance results are presented. A new version is in development for the ITER facility in France.
Clinical evidence has shown that chronic otitis media with cholesteatoma causes greater bone resorption than otitis media without cholesteatoma. What is the role of the epithelium and its products on ...the morbidity of cholesteatoma? We have studied the mechanism of collagenase production in cultures of rat epidermal cells and skin fibroblast-like cells under various conditions. The epithelial cells significantly induced mesenchymal cells to produce collagenase. We conclude that interaction between epithelial cells and fibroblast-like cells enhances production of collagenase. This enhancement of proteolytic activity may be crucial in the series of molecular events resulting in bone resorption associated with cholesteatoma.
The effect of polymorphonuclear leukocytes on collagenase production by fibroblast-like cells was studied in an in vitro cell culture system. An extract of rat intraperitoneal polymorphonuclear ...leukocytes induced significant collagenase production by rat skin fibroblast-like cells. Fibroblast-like cells cultured in the presence of polymorphonuclear leukocytes had many conspicuous microspikes on their surface and contained bundles of actin filaments in their cytoplasm. Polymorphonuclear leukocytes appears to be involved in bone resorption by inducing collagenase production by fibroblast-like cells, as well as by releasing their own enzymes involved in bone resorption.
Laminaria, a hygroscopic seaweed, was used to induce pressure within the rat tympanic cavity. Resorption of the bulla and cochlear walls occurred in all animals within 2 weeks. Cochlear fistulas were ...observed in four of nine animals after 2 weeks and in nine of 11 animals after 3 weeks. Preswelled laminaria inserted in the same area induced minimal bone resorption after 2 and 3 weeks. In animals given indomethacin following insertion of laminaria, both granulation-tissue formation and bone resorption were inhibited. Collagenase appeared localized in the inflammatory granulation tissue in the bone-resorption area, especially in fibroblasts, mononuclear cells, and osteoclasts. Results of this study suggested that pressure created by laminaria caused bone resorption by stimulating osteoclasts and granulation tissue.
Factors present in cholesteatoma connective tissue induce bone resorption in chronic otitis media. The presence of skin and its products appears to exacerbate the destructive influence of connective ...tissue. One exacerbating factor is pressure, shown in an animal model to increase bone resorption by influencing the subepithelial connective tissue. Consideration of pathogenic factors provides a rationale for modifications in the treatment of middle ear cholesteatoma.
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