| 1. |
- Beal, Jacob, et al.
(författare)
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Robust estimation of bacterial cell count from optical density
- 2020
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Ingår i: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
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Tidskriftsartikel (refereegranskat)abstract
- Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data.
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| 2. |
- Du, Banghua, et al.
(författare)
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Energy management and performance analysis of an off-grid integrated hydrogen energy utilization system
- 2024
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Ingår i: Energy Conversion and Management. - 0196-8904. ; 299
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Tidskriftsartikel (refereegranskat)abstract
- In integrated hydrogen energy utilization systems, due to the low efficiency of hydrogen/electricity conversion, coordination of energy management and efficient waste heat recovery is required to optimize performance. To address this challenge, this paper presents a comprehensive and sophisticated modeling and energy management strategy to enhance the off-grid energy utilization rate while prolonging the main components' lifetime. The developed model incorporates multiphase flow and heat transport balance for electricity and heat production, enabling a highly accurate representation of real-world behaviors of the system. The proposed off-grid operation strategy is complemented by a designed heat recovery scheme, ensuring the use of energy resources and waste heat. In addition, the proposed energy management strategy monitors the real-time status of each subsystem, actively reducing the number of harmful start-stop cycles of the hydrogen production system, thereby mitigating short-term power impacts and delaying its aging. Specifically, the voltage degradation of the reduction cell is reduced from 4.67 mV to 4.48 mV, the energy utilization rate is increased from 47.6 % to 53.9 %, and the energy efficiency of fuel cells significantly increases from 53.6 % to 78.1 %.
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| 3. |
- Du, Xinyu, et al.
(författare)
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Chlorinated Paraffins in Two Snake Species from the Yangtze River Delta : Tissue Distribution and Biomagnification
- 2020
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Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 54:5, s. 2753-2762
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Tidskriftsartikel (refereegranskat)abstract
- Very-short, short-, medium-, and long-chain chlorinated paraffins (vSCCPs, SCCPs, MCCPs, and LCCPs, respectively) were analyzed in different tissues of the terrestrial short-tailed mamushi (Gloydius brevicaudus) and the semi-aquatic red-backed rat snake (Elaphe rufodorsata) from the Yangtze River Delta, China. The total CP concentrations in liver, muscle, and adipose tissues in the two snake species were in the range of 2500-24 000, 4900-48 000, and 12-630 ng/g lw, respectively. Tissue burdens indicated that vSCCPs (C6-9) and SCCPs (C10-3) preferentially distributed to snake liver, while adipose was an important storage site and sink of MCCPs (C14-17) and LCCPs (C->18). On a lipid weight basis, vSCCPs and SCCPs were found in highest concentrations in red-backed rat snake liver and MCCPs and LCCPs in muscle, whereas for short-tailed mamushi, all CP groups were predominant in muscle, probably reflecting ecosystem/food web differences. Moreover, vSCCPs, SCCPs, MCCPs, and LCCPs were found to be biomagnified from black-spotted frogs to red-backed rat snakes with mean (maximum) biomagnification factors of 2.2 (3.4), 1.9 (3.7), 1.8 (2.8), and 1.7 (4.5), respectively. This is the first field study of biomagnification potential involving vSCCPs and LCCPs and highlights the need to include all CPs in studies.
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| 4. |
- Du, Xinyu, et al.
(författare)
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Distribution, behavior, and risk assessment of chlorinated paraffins in paddy plants throughout whole growth cycle
- 2022
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Ingår i: Environment International. - : Elsevier BV. - 0160-4120 .- 1873-6750. ; 167
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Tidskriftsartikel (refereegranskat)abstract
- Paddy plants provide staple food for 3 billion people worldwide. This study explores the environmental fate and behavior of a high-volume production emerging contaminants chlorinated paraffins (CPs) in the paddy ecosystem. Very-short-, short-, medium-, and long-chain CPs (vSCCPs, SCCPs, MCCPs, and LCCPs, respectively) were analyzed in specific tissue of paddy plants at four main growth stages and soils from the Yangtze River Delta, China throughout a full rice growing season. The total CP concentrations in the paddy roots, stalks, leaves, panicles, hulls, rice, and soils ranged from 181 to 1.74 × 103, 21.7–383, 19.6–585, 108–332, 245–470, 59.6–130, and 99.6–400 ng/g dry weight, respectively. The distribution profile indicated the translocation of SCCPs and MCCPs from soils to paddy tissue, highlighting their elevated bioaccumulative potential. The evolution of CP level/mass/pattern during the whole growth cycle suggested atmospheric CPs deposition on leaves and hulls, as well as stalk-rice transfer. CSOIL plant uptake model well predicted the level, distribution pattern, and bioconcentration factors (BCFs) of SCCPs and MCCPs in paddy shoot and recognized the soil-air-shoot pathway as the major contributor. Moreover, risk evaluation indicated that MCCPs intake and subsequent risks dominated the total exposure to CPs via rice ingestion. This is the first report on the occurrence, fate and risk assessment of all CPs classes in paddy ecosystems, and the results underline the potential health effects caused by the in-use MCCPs via rice ingestion.
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| 5. |
- Du, Xinyu, et al.
(författare)
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Evaluating oral and inhalation bioaccessibility of indoor dust-borne short- and median-chain chlorinated paraffins using in vitro Tenax-assisted physiologically based method
- 2021
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Ingår i: Journal of Hazardous Materials. - : Elsevier. - 0304-3894 .- 1873-3336. ; 402
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Tidskriftsartikel (refereegranskat)abstract
- Though ingestion and inhalation of dust have been suggested as important exposure routes contributing chlorinated paraffins (CPs) build-up in humans, the bioaccessibility of dust-borne CPs in the organ environment has not been well-studied, which may hinder an accurate estimation of exposure risks. In this study, the ingestion and inhalation bioaccessibility of dust-borne shortand median-chain CPs (SCCPs and MCCPs) was assessed using (colon-extended) physiologically based extraction test with the addition of Tenax. The ingestion bioaccessibility of SCCPs 51.5 %Cl, SCCPs 63 %Cl, MCCPs 42 %Cl, and MCCPs 57 %Cl was in ranges of 21.1-44.0 %, 11.7-45.8 %, 21.9-36.6 %, and 7.9-32.9 %, respectively. Multiple linear regression analysis demonstrated statistically significant associations of ingestion bioaccessibility with carbon chain length and chlorine substitution. The ingestion bioaccessibility of CPs also increased with co-existence of carbohydrate/protein. The inhalation bioaccessibility of SCCPs (16.7-38.7 % in artificial lysosomal fluid and 15.5-34.1 % in modified Gamble solution) was significantly higher than MCCPs (< 5 %), and varied with dust particle size/total organic carbon content. Our study indicates that modest bioaccessible fractions of CPs in dust should be taken into account to refine the estimation of human exposure, and their bioaccessibility may be affected by CP molecular size, nutritional content and dust property.
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| 6. |
- Du, Xinyu, et al.
(författare)
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Short-, Medium-, and Long-Chain Chlorinated Paraffins in Wildlife from Paddy Fields in the Yangtze River Delta
- 2018
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Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 52:3, s. 1072-1080
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Tidskriftsartikel (refereegranskat)abstract
- Short-chain chlorinated paraffins (SCCPs) were added to Annex A of the Stockholm Convention on Persistent Organic Pollutants in April, 2017. As a consequence of this regulation, increasing production and usage of alternatives, such as medium- and long-chain chlorinated paraffins (MCCPs and LCCPs, respectively), is expected. Little is known about the environmental fate and behavior of MCCPs and LCCPs. In the present study, SCCPs, MCCPs, and LCCPs were analyzed in nine wildlife species from paddy fields in the Yangtze River Delta, China, using atmospheric pressure chemical ionization-quadrupole time-of-flight mass spectrometry. SCCPs, MCCPs, and LCCPs were detected in all samples at concentrations ranging from <91-43000, 96-33 000, and 14-10000 ng/g lipid, respectively. Most species contained primarily MCCPs (on average 44%), with the exception of collared scops owl and common cuckoo, in which SCCPs (43%) accumulated to a significantly (i.e., p < 0.05) greater extent than MCCPs (40%). Cl-6 groups were dominant in most species except for yellow weasel and short-tailed mamushi, which contained primarily Cl-7 groups. Principal components analysis, together with CP concentrations and carbon stable isotope analysis showed that habitat and feeding habits were key factors driving CP accumulation and congener group patterns in wildlife. This is the first report of LCCP exposure in wildlife and highlights the need for data on risks associated with CP usage.
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| 7. |
- Du, Xinyu, et al.
(författare)
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Tissue-Specific Accumulation, Sexual Difference, and Maternal Transfer of Chlorinated Paraffins in Black-Spotted Frogs
- 2019
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Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 53:9, s. 4739-4746
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Tidskriftsartikel (refereegranskat)abstract
- The restriction on usage of short-chain chlorinated paraffins (SCCPs) under Stockholm Convention may promote the production and application of medium chain chlorinated paraffins (MCCPs) and long chain chlorinated paraffins (LCCPs) as substitutes. This study focused on the tissue-specific exposure to SCCPs, MCCPs, and LCCPs in black-spotted frog, a prevalent amphibian species in the Yangtze River Delta, China. The total CP concentrations in frog liver, muscle, and egg samples ranged of 35-1200, 6.3-97, and 6.8-300 ng/g wet weight (ww), respectively. Livers and eggs contained primary SCCPs (on average 78%) while MCCPs (43%) together with SCCPs (41%) were dominant in muscles. A significantly negative correlation was observed between hepatosomatic index and CPs concentration in liver (p < 0.01), indicating that CP exposure may lower survival rates of frogs by suppressing the energy storage in liver. Additionally, maternal transfer, an important uptake pathway for CPs, was evaluated for the first time by calculating the ratios of CP levels in eggs to those in their paired liver tissues. The ratio of egg to liver for CP congener groups raised with the increasing of log K-ow values, indicating mother to egg transport of CPs was related to the lipophilicity of the chemicals.
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| 8. |
- Kristan, Matej, et al.
(författare)
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The Ninth Visual Object Tracking VOT2021 Challenge Results
- 2021
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Ingår i: 2021 IEEE/CVF INTERNATIONAL CONFERENCE ON COMPUTER VISION WORKSHOPS (ICCVW 2021). - : IEEE COMPUTER SOC. - 9781665401913 ; , s. 2711-2738
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Konferensbidrag (refereegranskat)abstract
- The Visual Object Tracking challenge VOT2021 is the ninth annual tracker benchmarking activity organized by the VOT initiative. Results of 71 trackers are presented; many are state-of-the-art trackers published at major computer vision conferences or in journals in recent years. The VOT2021 challenge was composed of four sub-challenges focusing on different tracking domains: (i) VOT-ST2021 challenge focused on short-term tracking in RGB, (ii) VOT-RT2021 challenge focused on "real-time" short-term tracking in RGB, (iii) VOT-LT2021 focused on long-term tracking, namely coping with target disappearance and reappearance and (iv) VOT-RGBD2021 challenge focused on long-term tracking in RGB and depth imagery. The VOT-ST2021 dataset was refreshed, while VOT-RGBD2021 introduces a training dataset and sequestered dataset for winner identification. The source code for most of the trackers, the datasets, the evaluation kit and the results along with the source code for most trackers are publicly available at the challenge website(1).
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| 9. |
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| 10. |
- Niu, Dong, et al.
(författare)
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Novel brominated flame retardants in house dust from Shanghai, China : levels, temporal variation, and human exposure
- 2019
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Ingår i: Environmental Sciences Europe. - : Springer London. - 2190-4707 .- 2190-4715. ; 31:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Novel brominated flame retardants (NBFRs) have been increasingly used as alternatives to legacy BFRs (e.g., PBDEs and HBCDs) in consumer products, but are liable to emigrate and contaminate indoor dust. In this study, a total of 154 house dust samples including floor dust (FD) and elevated surface dust (ESD) were collected in the biggest metropolitan area (Shanghai) of East China in 2016. Limited information about temporal variation of NBFRs indoors is available, while the period of sampling is influential in human exposure estimates. Levels, temporal variation, and human exposure of seven target NBFRs such as decabromodiphenylethane (DBDPE), 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE), 2-ethylhexyl 2,3,4,5-tetrabromobenzoate (EHTBB), and bis(2-ethylhexyl) tetrabromophthalate (BEHTEBP) were investigated in indoor house dust.Results: Concentrations of Sigma(7)NBFRs ranged from 19.11 to 3099ng/g with a geomean of 295.1ng/g in FD, and from 34.74 to 404.6ng/g with a geomean of 117.9ng/g in ESD. The geomeans of DBDPE were 219.6ng/g in FD and 76.89ng/g in ESD, accounting for 90.5% and 80.5% of Sigma(7)NBFRs. Levels of EHTBB, BTBPE, and DBDPE in FD exceeded significantly those in ESD. The temporal variation in Sigma(7)NBFRs in FD was ranked as summer>winter>autumn>spring. The daily exposure doses (DEDs) of Sigma(7)NBFRs via dust ingestion decreased as: infants>toddlers>children>teenagers>adults. Infants showed the highest DED in FD, 9.1ng/kg bw/day.Conclusions: DBDPE clearly dominated the NBFRs in both FD and ESD, but the concentrations of DBDPE in this study were generally moderate compared with the other international studies. Dust ingestion was the major pathway of human exposure to NBFRs indoors. About eightfold difference in exposure estimates between infants and adults showed that infants faced elevated exposure risks in FD. This study highlighted the necessity to estimate human exposure of NBFRs for different age groups using FD and ESD, respectively.
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