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Quantitative filter forensics (QFF) is a method for estimating the time-averaged concentration of particle-bound containments using filter metadata and its extracted dust. In this study, QFF was applied to dust samples extracted from four types of HVAC filters deployed in 20 homes from December 2016 to December 2017 in Toronto, Canada. The analysis covered six allergens, eight phthalates, and 12 polycyclic aromatic hydrocarbons (PAHs). The allergen results from four homes showed elevated concentrations of cat and dog allergens (Fel d 1 and Can f 1) in homes with cats or dogs. All eight phthalates were detected, dominated by diisononyl phthalate (DiNP) and bis(2-ethylhexyl) phthalate (DEHP), with median concentrations of 4.27 ng/m³ and 4.20 ng/m³, respectively. All PAHs, except anthracene, were detected in over 50 % of the homes, with benzo[a]pyrene being the most abundant (median concentration of 0.067 ng/m³). Median concentrations of all semivolatile organic compounds (SVOCs) were lower in winter 2016 compared to spring 2017, potentially due to losses of more volatile SVOCs from filters because of higher filtration volumes in winter, in addition to differences in sources and ventilation rates. All phthalate and most PAH concentrations were one to two orders of magnitude lower compared to those found from QFF in apartments in Toronto social housing multi-unit residential buildings (MURB), indicating those with lower socio-economic status (SES) were exposed to higher SVOC concentrations. Occupant density was positively related to most phthalate and specific PAH concentrations, while environmental factors including room temperature, relative humidity, and supply air temperature were not. • Quantitative filter forensics enables long-term mean SVOC concentration estimation. • Large variations in phthalate and PAH concentrations across homes. • Seasonal variations likely caused by sources, ventilation, and sampling artefacts. • SVOC concentrations are not strongly correlated with filter efficiency. • SVOC concentrations were lower in single-family homes than in social housing units. [ABSTRACT FROM AUTHOR]

Building electrification is the movement to shift building operational energy use from fossil fuels toward electricity. It has been pursued mainly to reduce greenhouse gas (GHG) emissions from the building sector. We present here ten questions concerning building electrification and attempt to answer them in the context of the existing literature. Our questions span dimensions of policy, life cycle impacts on energy and environment, technological advances and challenges, indoor and outdoor air quality, health, economics, and social-behavioral factors. We find that while much of the extant research predicts that building electrification will provide benefits in terms of GHG emissions, pollutant exposures, and economic impacts, it remains limited to a narrow set of geographic regions and typically fails to capture the full extent of life cycle environmental impacts. Additionally, despite logical inferences for likely health benefits, we were unable to identify explicit studies of the health impacts of building electrification. We also find a common theme that, for building electrification to be successful in reducing GHG emissions, costs, and adverse grid impacts, it should be approached in parallel with increased building energy efficiency, grid renewable power, and smart grid infrastructure. Finally, we find that people hold strong opinions about fuel options in their homes, and the relationship between preferences and energy use is complicated. To shift people's beliefs around electrification, government-originating communications can highlight the benefits, but one must still account for heterogeneous household conditions. We conclude by suggesting key research areas needed to approach building electrification effectively and equitably. • Comprehensive LCAs are needed to understand building electrification impacts. • Electric grid resilience is a key research area for a successful transition. • People hold strong opinions about fuel options, especially for cooking in homes. • Social-behavioral research is needed to promote building electrification across communities. • Studies should consider broad geographic locations and diverse populations. [ABSTRACT FROM AUTHOR]

• The Black-Litterman model is extended to build an efficient portfolio. • The newly constructed portfolio enjoys a higher Sharpe ratio. • The result is robust under different confidence levels and sample intervals. Macroeconomic environment is an essential factor affecting asset return, but it is difficult to construct portfolios using macro information quantitatively in traditional models. In this paper, we extend the Black-Litterman framework to build an efficient portfolio by using views containing macro information and prior market distribution reflecting micro information. In order to enhance the model's flexibility, entropy pool method is used. Empirical evidence shows that with reasonable allocation across economic stages, the newly constructed portfolio enjoys a higher level of Sharpe ratio compared to classic allocation models, and the result is robust under different circumstance. [ABSTRACT FROM AUTHOR]

Few studies have been conducted on changes in the amylose content and rapid visco‐analyzer (RVA) profile characteristics of noodle rice cultivars under different ecological conditions. This research was conducted in 2017 and 2018 to evaluate changes in amylose content and RVA profile characteristics of ten noodle rice cultivars at three test sites. The cultivars were planted in Nanning, Hengyang, and Nanchang in 2017. Four cultivars were planted at each site on seven sowing dates with an interval of 15 d in 2018. Grain amylose content and RVA profile characteristics were determined after the rice had been stored for three months. The results showed that there were significant differences between the cultivars in the amylose content and RVA profile characteristics. The RVA profile characteristics of the 10 rice cultivars did not exhibit a similar trend for the three test sites. The average coefficient of variation was 8.6% for the amylose content, greater than 25% for the breakdown (BD) and setback (SB); 10 to 20% for the consistency (CSV) and peak viscosity (PV); and less than 10% for the trough viscosity (TV), final viscosity (FV), peak time (PT), and pasting temperature (PaT). The correlation analysis showed that the amylose content was significantly correlated with the PT, TV, BD, PaT, SB, and FV. It was concluded that there were significant differences in the amylose content and RVA profile characteristics between the rice cultivars and significant genetic‐environment interaction effects. The amylose content of the special noodle rice cultivars was significantly correlated with the RVA profile characteristics. [ABSTRACT FROM AUTHOR]

Abstract Recirculating central forced-air heating, ventilation, and air conditioning (HVAC) systems are common in residential buildings in North America. Runtime, the fraction of time any part of the HVAC system operates, is an important parameter to evaluate system performance and its impact on building energy use and indoor air quality. Different methods have been developed to assess runtime. In this paper, we evaluate the strengths and limitations of existing direct and indirect approaches to access runtime. Using data collected from one study in Toronto, Ontario and one in Austin, Texas, we improved the algorithm of an indirect method by Thornburg et al. (2004) which calculates conditioning runtime based on the air temperature in the supply duct. We applied the improved algorithm to two additional studies in Toronto and compared runtime results from this temperature method with other direct methods. The results show that the algorithm is reliable with a small annual underestimation (1.5–2.5% absolute difference). We also found that runtime varies considerably among similar homes with the same ambient conditions, thus it is not reliable to use outdoor temperatures to predict runtime. A further analysis on the real-time temperature and motor signals shows that the accuracy of the algorithm is influenced by system sequencing (i.e. fan and conditioning unit starting and/or stopping not being coincident in time) and fan-only operation. Overall, this work illustrates the importance to measure runtime due to its large variation and that the temperature method is a reliable approach to access runtime in appropriate homes. Highlights • Residential HVAC runtime varies considerably between homes and over time in the same home. • Existing approaches often require access to HVAC system components and specialized knowledge. • We present a method to calculate runtime using duct air temperatures and an algorithm. • Heating and cooling runtime results are predicted with high accuracy, but fan-only periods cannot be assessed. • The results show the algorithm is reliable with 1.5–2.5% (abs. diff.) annual underestimation of runtime. [ABSTRACT FROM AUTHOR]

Abstract The study evaluated source apportionment of heavy metals in vegetable samples from the potential sources of fertilizer, water and soil samples collected along the Changjiang River delta in China. The results showed that 25.72% of vegetable samples (Brassica chinensis L.) containing Pb, and Cd, Cu, Hg and Zn at relatively serious levels were from soil. Combined with principle component analysis (PCA) and cluster analysis (CA), the results of the spatial distribution of heavy metals in different environmental media indicated that fertilizer, water and soil were the main sources of heavy metals in vegetables. The results of multivariate linear regression (MLR) using partition indexes (P) showed that fertilizer contributed to 38.5%, 40.56%, 46.01%, 53.34% and 65.25% of As, Cd, Cu, Pb and Zn contents in vegetables, respectively. In contrast, 44.58% of As, 32.57% of Hg and 32.83% of Pb in vegetables came from soil and 42.78% of Cd and 66.97% of Hg contents in vegetables came from the irrigation water. The results of PCA and CA verified that MLR using P was suitable for determining source apportionment in a vegetable. A health risk assessment was performed; As, Cd and Pb contributed to more than 75% of the total hazard quotient (THQ) values and total carcinogenic risk values (Risk total) for adults and children through oral ingestion. More than 70% of the estimated THQ and Risk total is contributed by water and fertilizer. Therefore, it is necessary to increase efforts in screening limits/levels of heavy metals in fertilizer and irrigation water and prioritize appropriate pollution management strategies. Highlights • Fertilizer, soil and water were determined as main sources of heavy metals in vegetable. • Modified MLR indicated that fertilizer contributed over 38% of As, Cd, Cu, Pb, Zn relatively. • Over 70% of the THQ and Risk total for adults and children were contributed by fertilizer and water though vegetable ingestion. [ABSTRACT FROM AUTHOR]

Abstract Ventilation using outdoor air can have both favorable and unfavorable impacts on indoor air pollution. It also can be an important contributor to energy use in buildings. Outdoor ventilation air change rate (ACR), the rate at which outdoor air enters a building divided by its volume, is a temporally dynamic metric that can be used to characterize ventilation performance of buildings. Conventional measurement techniques for ACR have either complex or invasive experimental procedures, or present a temporal snapshot of ACR. In this study, we further developed and explored a novel signal processing approach to measure yearlong time-resolved ACR in a residence using the variations in indoor and outdoor CO 2 concentrations. Results showed that ACR varied considerably over the year [geometric mean (GM) = 0.47/h, geometric standard deviation (GSD) = 3.44] and that the air change rates calculated from the signal processing approach were in good agreement (on average, within 13%) with those measured simultaneously from 15 hour-long decay periods. In addition, estimates of ACR were largely insensitive to the occupancy status of the building. This behavior may be because the indoor CO 2 concentration variations introduced by changes in occupancy status were not large enough to impact long-term ACR values, but they may be sufficient to impact short-term ACR values. Moreover, we anticipate that cut-off frequency and filter order, two parameters needed for the signal processing approach, may be building-specific and can influence calculations of air change rates in a given building. The results suggest that this approach has promise for assessing time-varying ACR in buildings with time-resolved indoor and outdoor concentration measurements. Highlights • Ventilation measured with a signal processing approaches reveals temporal dynamics in air exchange rate (AER). • The approach requires measurement of indoor and outdoor CO 2 concentrations but no release of a tracer gas. • Over a year the geometric mean (geometric standard deviation) AER in a residence was 0.47/h (3.44). • The application of the signal processing approach is sensitive to the selection of the concentration filtering parameters. • The results suggest a valuable way to assess time-resolved ventilation rates in buildings [ABSTRACT FROM AUTHOR]

Trigeminal neuralgia is a common chronic maxillofacial neuropathic pain disorder, and voltage-gated sodium channels (VSGCs) are likely involved in its pathology. Prior studies report that pituitary adenylate cyclase-activating polypeptide (PACAP), a neuropeptide highly expressed in the trigeminal ganglion, may contribute to dorsal root ganglion neuron excitability by modulating the Nav1.7. We investigated whether PACAP can regulate Nav1.7 through the mitogen-activated protein kinase/ERK kinase/extracellular-signal-regulated kinase (MEK/ERK) pathway in the trigeminal ganglion after chronic constriction injury of the infraorbital nerve (ION-CCI) in rats. Sprague-Dawley rats underwent ION-CCI, followed by intrathecal injection of PACAP 6–38 (PAC1 receptor antagonist) and PD98059 (MEK/ERK antagonist). Quantitative real-time PCR and western blot were used to quantify ATF3, PACAP, ERK, p-ERK, and Nav1.7 expression. The mechanical pain threshold decreased from day 3 to day 21 after ION-CCI and reached the lowest testing value by day 14; however, it increased after PACAP 6–38 and PD98059 injections. Additionally, ION-CCI surgery increased ATF3, PACAP, and p-ERK expression in the rat trigeminal ganglion and decreased Nav1.7 and PAC1 receptor expression; however, there was no difference in ERK expression. PACAP 6–38 injection significantly decreased PACAP, p-ERK, and Nav1.7 expression and increased the PAC1 receptor expression, with no change in ERK expression. Moreover, PD98059 injection decreased PACAP, p-ERK, and Nav1.7 expression and increased the expression of PAC1 receptor. After ION-CCI, PACAP in the rat trigeminal ganglion can modulate Nav1.7 through the MEK/ERK pathway via the PAC1 receptor. Further, PACAP inhibition alleviates allodynia in ION-CCI rats. [ABSTRACT FROM AUTHOR]

Soil heavy metals and their bioaccumulation in agricultural products have attracted widespread concerns, yet the transfer and accumulation characteristics of heavy metals in different soil–crop systems was rarely investigated. Soil and crop samples were collected from the typical agricultural areas in the Yangtze River Delta region, China. The concentrations of Cu, Pb, Zn, Cd and Hg in the soils, roots and grains of rice ( Oryza Sativa L. ), wheat ( Triticum L. ) and canola ( Brassica napus L .) were determined in this study. Transfer ability of heavy metals in soil-rice system was stronger than those in soil-wheat and soil-canola systems. The wheat showed a strong capacity to transfer Zn, Cu and Cd from root to the grain while canola presented a restricting effect to the intake of Cu and Cd. Soil pH and total organic matter were major factors influencing metal transfer from soil to rice, whereas soil Al 2 O 3 contents presented a negative effect on heavy metal mobility in wheat and canola cultivation systems. The concentration of Zn and Cd in crop grains could well predicted according to the stepwise multiple linear regression models, which could help to quantitatively evaluate the ecologic risk of heavy metal accumulation in crops in the study area. [ABSTRACT FROM AUTHOR]

The transport behavior of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) in porous media controls their final environmental fate and risk. Current work used column experiments and a two-site kinetic retention model to reveal the effect of dissolved organic matter (DOM) on their migration under the interference of solution ionic strength and cation type. Results showed the migration of PFOA and PFOS was inhibited by 1 mg/L DOM but promoted by 10 mg/L DOM. Compared with the presence of 1 mg/L DOM, increasing ionic strength (1–10 mM) and changing cation type (Na+ to Ca2+) had a stronger inhibitory effect on PFOS transport. However, the opposite is true for PFOA due to its different molecular structure and adsorption behavior from PFOS. Ca2+ was more tended to interact with PFOS (owing to its sulfonate group) than with PFOA, and PFOS had a higher affinity with Ca2+ than with DOM. Cation bridging and increasing ionic strength could promote the inhibition of PFOA and PFOS transport by 1 mg/L DOM. The influence of DOM on PFASs transport could be very complex in the natural environment due to the variable solution chemistry conditions of pore water and physico-chemical properties of PFASs. The results of this work have scientific significance for better evaluating and managing the environmental risk of soil PFASs. [Display omitted] • DOM-mediated transport of PFOA and PFOS is solution chemistry dependent. • PFOA and PFOS transport was inhibited by deposited DOM but facilitated by free DOM. • The DOM-affected transport of PFOA was less disturbed by ionic strength and Ca2+. • PFOS preferred to interact with Ca2+ rather than DOM. • Ca2+ and higher ionic strength promoted the effect of deposited DOM. [ABSTRACT FROM AUTHOR]

For most multi-purpose reservoirs, there is a conflict between the flood control and refill operations. Refill before the end of the flood season is a valuable and effective solution to the conflict. In this paper, we present a method to derive the optimal refill rule for multi-purpose reservoir considering flood control risk. The paper begins with an investigation of the temporal trends of historical reservoir inflow series during refill period by the methods of linear regression, Mann–Kendall and Spearman's rho test. Six refill rules are then proposed. A procedure to couple a flood control risk module with utilization benefits analysis module is then developed to derive the optimal refill rule. China's Three Gorges Reservoir (TGR) is selected as a case study. The application results show that the optimal refill rule is that refill begins on September 1 with storage level reaching 160 m on September 30 linearly. Compared with the original rule, the optimal refill rule can increase hydropower generation by 7.19%, decrease spilled water by 25.07%, and improve the fullness storage rate to 95.35%, without increasing flood control risk. [ABSTRACT FROM AUTHOR]

Abstract: Due to the frequent water exchange and turbulence between Poyang Lake and Yangtze River, the measured runoff hydrograph at the Hukou outlet control station is unable to be directly used in hydrological model calibration. As a result, the rainfall runoff relationship and water budget analysis in Poyang Lake regions is an unsolved problem so far. In this study, the basin area analogue and water budget methods was used to modified runoff hydrograph at the Hukou, and multiple-input single-output system model was used to derive intervening basin runoff. The Variable Infiltration Capacity (VIC) distributed hydrological model based on different types of remote sensing data was used to simulate daily runoff in the ungauged Poyang Lake Intervening Basin (PLIB). The comparison of estimated and simulated daily runoff hydrographs shows that the VIC model is performed relatively well. It is proved that with the help of remote sensed data, important hydrological characteristics of the PLIB can be reproduced and predicted. [Copyright &y& Elsevier]

• The effect of hydrogen on nucleation, growth and etching of h-BN is demonstrated. • The etching of h-BN is terminated under high hydrogen flow. • Hydrogen plays a dual role of activator and passivation during h-BN growth. • Vertical graphene/h-BN heterostructure was achieved in one-pot by conventional CVD. Graphene/hexagonal boron nitride (h-BN) heterostructures have attracted a lot of research interests due to their superior electronic properties in field effect transistor devices and the novel physical properties such as fractional fractal quantum hall effect and massive Dirac fermions. Chemical vapor deposition (CVD) is the most common method to synthesize h-BN and graphene, however, the directly growth of graphene/h-BN heterostructures remains challenging. Here we report the crucial impact of hydrogen on the nucleation density, growth rate and etching rate in the h-BN CVD growth. It is found that the nucleation density increases monotonically, whereas the growth rate and etching rate first increases and then decreases with the increasing hydrogen partial pressure. Benefitting from the understanding of the crucial role of hydrogen, we successfully grow the graphene/h-BN vertical heterostructures by low pressure CVD in one-pot through the modulation of hydrogen partial pressure. The field effect transistor (FET) fabricated using graphene/h-BN heterostructure shows better performance with higher carrier mobility and lower level of doping than the one without h-BN. Our direct synthesis approach paves a new pathway for large-scale production of graphene/h-BN heterostructures and could be applied for the synthesis of other van der Waals heterostructures. [ABSTRACT FROM AUTHOR]

The effects of Bacillus subtilis inoculation on the growth and Cd uptake of alfalfa were evaluated in this research using pot experiments, and the relevant biochemical mechanisms were first investigated by combined microbial diversity and nontarget metabolomics analyses. The results indicated that inoculation with alfalfa significantly decreased the amount of plant malondialdehyde (MDA) and improved the activities of plant antioxidant enzymes and soil nutrient cycling-involved enzymes, thereby promoting biomass by 29.4%. Inoculation also increased Cd bioavailability in rhizosphere soil by 12.0% and Cd removal efficiency by 139.3%. The biochemical mechanisms included enhanced bacterial diversity, transformed microbial community composition, regulated amounts of amino acids, fatty acids, carbohydrates, flavonoids and phenols in rhizosphere soil metabolites, and modulations of the corresponding Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. These responses were beneficial to microbial activity, nutrient cycling, and Cd mobilization, detoxification, and decontamination by alfalfa in soil. This study, especially the newly identified differential metabolites and metabolic pathways, provides new insights into mechanism revelation and strategy development in microbe-assisted phytomanagement of heavy metal-contaminated soils. ga1 • Bacillus subtilis inoculation markedly promoted the growth and Cd uptake of alfalfa. • The rhizobacteria enhanced microbial community diversity and enzyme activity in soil. • Metabolomics mechanisms for bacteria-aided phytoextraction were firstly demonstrated. • Regulated metabolites included amino acids, fatty acids, carbohydrates and flavonoids. • Inoculation improved Cd mobilization, detoxification and decontamination by alfalfa. [ABSTRACT FROM AUTHOR]

Effectiveness is commonly used to evaluate the particle removal performance of residential filtration systems. Previous investigations have used various effectiveness metrics to assess system performance through modeling efforts. However, the model assumptions often lead to an overestimation of effectiveness. Further, none of the studies considered the impact of realistic residential heating, ventilation, and air conditioning (HVAC) system operation patterns. In this investigation, we evaluated the strength and limitations of various effectiveness metrics. We identified exposure reduction as the most appropriate metric for modeling analyses because it does not rely on any steady-state assumptions. A time-varying mass balance model that accounts for system operation parameters including runtimes and cycle on-times, and the impact of indoor emission sources is used to simulate the changes in indoor particulate matter smaller than 2.5 μm (PM 2.5) concentration with and without system operation. The effectiveness results show that runtime has the biggest impact on exposure reduction. At a fixed runtime, short cycle on-times and the coincidence of system operation with emission events can further improve the removal performance of the system. Thus, the particle removal performance of a filtration system can be optimized by changing its operation pattern while still maintaining similar fan energy use. • Existing effectiveness metrics could overestimate HVAC filtration performance. • We present a framework to directly assess filtration performance. • The simulation results suggest runtime has the biggest impact on effectiveness. • Shorter cycle on-times bring more filtration benefit. • Filtration performance can be optimized by synchronizing operation with emissions. [ABSTRACT FROM AUTHOR]