Validity and Reliability of a Protocol to Establish Human Critical Environmental Limits (PSU HEAT)

The PSU HEAT protocol has been used to determine critical environmental limits, i.e., those combinations of ambient temperature and humidity above which heat stress becomes uncompensable and core temperature rises continuously. However, no studies have rigorously investigated the reliability and validity of this experimental protocol. Here, we assessed the (1) between-visit reliability and (2) validity of the paradigm. Twelve subjects (5M/7W; 25±4 yr) completed a progressive heat stress protocol during which they walked on a treadmill (2.2 mph, 3% gradient) in a controllable environmental chamber. After an equilibration period, either dry-bulb temperature (Tdb) was increased every 5 min while ambient water vapor pressure (Pa) was held constant (Tcrit experiments) or Pa was increased every 5 min while Tdb was held constant (Pcrit experiments) until an upward inflection in gastrointestinal temperature (Tgi) was observed. For reliability experiments, 11 subjects repeated the same protocol on a different day. For validity experiments, 10 subjects performed a Tcrit experiment at their previously determined Pcrit or vice versa. The between-visit reliability (intraclass correlation coefficient, ICC) for critical environmental limits was 0.98. Similarly, there was excellent agreement between original and validity trials for Tcrit (ICC = 0.95) and Pcrit (ICC = 0.96). Further, the wet-bulb temperature at the Tgi inflection point was not different during reliability (p = 0.78) or validity (p = 0.32) trials compared to original trials. These findings support the reliability and validity of this experimental paradigm for the determination of critical environmental limits for maintenance of human heat balance.

An environmental engineering approach to wastewater treatment with bivalves in the coastal zone

High tolerance to pollution and filtration capacity of some seston-eating bivalves and mussels of g. Mytilus first of all, principally determine mussel populations as a powerful natural biofilter. Both marine and freshwater mussels consume relatively large amounts of seston, feeding directly on the primary producers. Particles with contaminants extracted from ambient water during the filtration are accumulated in mussel pseudofaeces and faeces discharged after digestion. These specific particles of faeces and soft pseudofeaces become very suitable substrata for bacteria development with following contaminant destruction. Moreover, such biodeposits appeared to be the nutritious food for bottom detritophages, in particular of polychaetes and amphipods. Some fluid metabolites excreted by mussels, i.e. dissolved organic matter (DOM) have a pronounced biological activity to producers. In general, mussels possess high resistance to acute and chronic pollution stress, although their growth may slow down and even stops. In clean conditions food supply is the most important factor in determining activity and growth rate of mussels for northern environment. Mussel and some other aquaculture, as a relatively new application of environmental engineering is able to improve the recycling of nutrients from wastewater to bioproduction and greatly reduce the risk of environmental degradation in the coastal zone.

Seasonal Dynamics of Epiphytic Microbial Communities on Marine Macrophyte Surfaces

Surfaces of marine macrophytes are inhabited by diverse microbial communities. Most studies focusing on epiphytic communities of macrophytes did not take into account temporal changes or applied low sampling frequency approaches. The seasonal dynamics of epiphytic microbial communities was determined in a meadow of Cymodocea nodosa invaded by Caulerpa cylindracea and in a monospecific settlement of C. cylindracea at monthly intervals. For comparison the ambient prokaryotic picoplankton community was also characterized. At the OTU level, the microbial community composition differed between the ambient water and the epiphytic communities exhibiting host-specificity. Also, successional changes were observed connected to the macrophyte growth cycle. Taxonomic analysis, however, showed similar high rank taxa (phyla and classes) in the ambient water and the epiphytic communities, with the exception of Desulfobacterota, which were only found on C. cylindracea. Cyanobacteria showed seasonal changes while other high rank taxa were present throughout the year. In months of high Cyanobacteria presence the majority of cyanobacterial sequences were classified as Pleurocapsa. Phylogenetic groups present throughout the year (e.g., Saprospiraceae, Rhodobacteraceae, members without known relatives within Gammaproteobacteria, Desulfatitalea, and members without known relatives within Desulfocapsaceae) constituted most of the sequences, while less abundant taxa showed seasonal patterns connected to the macrophyte growth cycle. Taken together, epiphytic microbial communities of the seagrass C. nodosa and the macroalga C. cylindracea appear to be host-specific and contain taxa that undergo successional changes.

Ecological Risk Assessment of Amoxicillin, Enrofloxacin, and Neomycin: Are Their Current Levels in the Freshwater Environment Safe?

Veterinary pharmaceuticals may cause unexpected adverse effects on non-target aquatic species. While these pharmaceuticals were previously identified as priority compounds in ambient water, their ecological risks are relatively unknown. In this study, a series of chronic toxicity tests were conducted for these pharmaceuticals using algae, two cladocerans, and a fish. After a 21-d exposure to amoxicillin, enrofloxacin, and neomycin, no observed effect concentration (NOEC) for the reproduction of Daphnia magna was detected at 27.2, 3.3, and 0.15 mg/L, respectively. For the survival of juvenile Oryzias latipes following the 40-d exposure, NOEC was found at 21.8, 3.2, and 0.87 mg/L, respectively. Based on the results of the chronic toxicity tests and those reported in the literature, predicted no-effect concentrations (PNECs) were determined at 0.078, 4.9, and 3.0 µg/L for amoxicillin, enrofloxacin, and neomycin, respectively. Their hazard quotients (HQs) were less than 1 at their average levels of occurrence in ambient freshwater. However, HQs based on the maximum detected levels of amoxicillin and enrofloxacin were determined at 21.2 and 6.1, respectively, suggesting potential ecological risks. As the potential ecological risks of these veterinary pharmaceuticals at heavily contaminated sites cannot be ignored, hotspot delineation and its management are required.

A STUDY INTO DESIGNING AN AMBIENT WATER BOTTLE THAT SUPPORTS USERS' WATER-INTAKE TRACKING PRACTICES

Taking on the challenge of motivating users to drink water regularly, we designed a smart water bottle that can track water intake behavior and inform users about this behavior through ambient feedback. We then conducted two studies to explore the bottle's feedback design from the perspective of users and designers. First, we conducted semi-structured interviews with 10 prospective users and found that they would like to receive personalized, precise, gamified and reminding feedback. Second, we conducted a design workshop with 13 professional designers to explore the range of visualizations that can be used to give feedback. Analyzing these visualizations, we identified three reminder types (augmenting, restoring and balancing) and six visualization styles grouped according to three dimensions of ambient displays (representation fidelity, notification level, aesthetic emphasis). In this paper, we first explain our water bottle concept along with existing solutions. Then, we report the results of these studies. Finally, we discuss the potential implications of the results for our own work as well as for designing ambient displays aimed at supporting users' water intake tracking practices.

The effect of water on colloidal quantum dot solar cells

Almost all surfaces sensitive to the ambient environment are covered by water, whereas the impacts of water on surface-dominated colloidal quantum dot (CQD) semiconductor electronics have rarely been explored. Here, strongly hydrogen-bonded water on hydroxylated lead sulfide (PbS) CQD is identified. The water could pilot the thermally induced evolution of surface chemical environment, which significantly influences the nanostructures, carrier dynamics, and trap behaviors in CQD solar cells. The aggravation of surface hydroxylation and water adsorption triggers epitaxial CQD fusion during device fabrication under humid ambient, giving rise to the inter-band traps and deficiency in solar cells. To address this problem, meniscus-guided-coating technique is introduced to achieve dense-packed CQD solids and extrude ambient water, improving device performance and thermal stability. Our works not only elucidate the water involved PbS CQD surface chemistry, but may also achieve a comprehensive understanding of the impact of ambient water on CQD based electronics.