| 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. |
- Gao, Xindi, et al.
(författare)
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Cryptococcal Hsf3 controls intramitochondrial ROS homeostasis by regulating the respiratory process
- 2022
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 13:1
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Tidskriftsartikel (refereegranskat)abstract
- Mitochondrial quality control prevents accumulation of intramitochondrial-derived reactive oxygen species (mtROS), thereby protecting cells against DNA damage, genome instability, and programmed cell death. However, underlying mechanisms are incompletely understood, particularly in fungal species. Here, we show that Cryptococcus neoformans heat shock factor 3 (CnHsf3) exhibits an atypical function in regulating mtROS independent of the unfolded protein response. CnHsf3 acts in nuclei and mitochondria, and nuclear- and mitochondrial-targeting signals are required for its organelle-specific functions. It represses the expression of genes involved in the tricarboxylic acid cycle while promoting expression of genes involved in electron transfer chain. In addition, CnHsf3 responds to multiple intramitochondrial stresses; this response is mediated by oxidation of the cysteine residue on its DNA binding domain, which enhances DNA binding. Our results reveal a function of HSF proteins in regulating mtROS homeostasis that is independent of the unfolded protein response.
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| 3. |
- Li, Cheng, et al.
(författare)
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Optimal Planning of Community Integrated Energy Station Considering Frequency Regulation Service
- 2021
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Ingår i: Journal of Modern Power Systems and Clean Energy. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 2196-5625 .- 2196-5420. ; 9:2, s. 264-273
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Tidskriftsartikel (refereegranskat)abstract
- With the extensive integration of high-penetration renewable energy resources, more fast-response frequency regulation (FR) providers are required to eliminate the impact of uncertainties from loads and distributed generators (DGs) on system security and stability. As a high-quality FR resource, community integrated energy station (CIES) can effectively respond to frequency deviation caused by renewable energy generation, helping to solve the frequency problem of power system. This paper proposes an optimal planning model of CIES considering FR service. First, the model of FR service is established to unify the time scale of FR service and economic operation. Then, an optimal planning model of CIES considering FR service is proposed, with which the revenue of participating in the FR service is obtained under market mechanism. The flexible electricity pricing model is introduced to flatten the peak tie-line power of CIES. Case studies are conducted to analyze the annual cost and the revenue of CIES participating in FR service, which suggest that providing ancillary services can bring potential revenue.
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| 4. |
- Li, Shuangjun, et al.
(författare)
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Cyclic performance evaluation of CO2 adsorption using polyethylene terephthalate plastic-waste-derived activated carbon
- 2023
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Ingår i: Fuel. - : ELSEVIER SCI LTD. - 0016-2361 .- 1873-7153. ; 331
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Tidskriftsartikel (refereegranskat)abstract
- Polyethylene terephthalate (PET) plastic-waste-derived activated carbons have recently been developed and exhibit excellent CO(2 )adsorption uptake. However, the CO2-adsorption performance of such recycled materials has only been considered on a basic characterization level and has not yet been evaluated in carbon capture cycles, thereby making biased analyses inevitable. Consequently, a whole chain including the material, process, and cycle is essential for comprehensively analyzing and evaluating novel CO2 adsorbents. Therefore, in this study, various CO2-capture cycles using PET plastic-waste-derived activated carbon adsorbents were numerically simulated, the cyclic CO2-adsorption performances were evaluated, and the application scenario was optimized. A methodology for evaluating the cyclic CO2-adsorption performance of PET plastic-waste-derived activated carbon was proposed for CO(2 )capture. The results suggested that the temperature/vacuum swing adsorption cycle was superior and that its maximum exergy efficiency reached 32.90%.
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| 5. |
- Li, Y., et al.
(författare)
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Effects of organic composition on mesophilic anaerobic digestion of food waste
- 2017
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Ingår i: Bioresource Technology. - : Elsevier Ltd. - 0960-8524 .- 1873-2976. ; 244, s. 213-224
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Tidskriftsartikel (refereegranskat)abstract
- Anaerobic digestion of food waste (FW) has been widely investigated, however, little is known about the influence of organic composition on the FW digestion process. This study aims to identify the optimum composition ratios of carbohydrate (CA), protein (CP) and lipid (EE) for maintaining high methane yield and process stability. The results show that the CA–CP–EE ratio was significantly correlated with performance and degradability parameters. Controlling the CA–CP–EE ratio higher than 1.89 (CA higher than 8.3%, CP lower than 5.0%, and EE lower than 5.6%) could be an effective way to maintain stable digestion and achieve higher methane production (385–627 mL/g VS) and shorter digestion retention (196–409 h). The CA-CP-EE ratio could be used as an important indicator for digestion performance. To effectively evaluate organic reduction, the concentration and removal efficiency of organic compositions in both solid phases and total FW should be considered.
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| 6. |
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| 7. |
- Li, Y., et al.
(författare)
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Effects of organic composition on the anaerobic biodegradability of food waste
- 2017
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Ingår i: Bioresource Technology. - : Elsevier Ltd. - 0960-8524 .- 1873-2976. ; 243, s. 836-845
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Tidskriftsartikel (refereegranskat)abstract
- This work investigated the influence of carbohydrates, proteins and lipids on the anaerobic digestion of food waste (FW) and the relationship between the parameters characterising digestion. Increasing the concentrations of proteins and lipids, and decreasing carbohydrate content in FW, led to high buffering capacity, reduction of proteins (52.7–65.0%) and lipids (57.4–88.2%), and methane production (385–627 mLCH4/g volatile solid), while achieving a short retention time. There were no significant correlations between the reduction of organics, hydrolysis rate constant (0.25–0.66 d−1) and composition of organics. Principal Component Analysis revealed that lipid, C, and N contents as well as the C/N ratio were the principal components for digestion. In addition, methane yield, the final concentrations of total ammonia nitrogen and free ammonia nitrogen, final pH values, and the reduction of proteins and lipids could be predicted by a second-order polynomial model, in terms of the protein and lipid weight fraction.
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| 8. |
- Li, Yangyang, et al.
(författare)
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Effects of pungency degree on mesophilic anaerobic digestion of kitchen waste
- 2016
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Ingår i: Applied Energy. - : Elsevier BV. - 0306-2619 .- 1872-9118. ; 181, s. 171-178
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Tidskriftsartikel (refereegranskat)abstract
- This study investigated the influence of pungency degrees (PDs) on mesophilic anaerobic digestion of kitchen waste (KW). Batch tests were performed to evaluate the methane potential and production rate and the effect of PDs on organics degradation efficiency (in terms of volatile solids, protein and ether extract) at mesophilic temperature. Koch and Drewes model and modified Gompertz model were applied to assess the effects of PDs on the hydrolysis rate constant, biomethane yield rate and lag time. The results revealed that with the increasing contributions of PDs, the methane yield, organics degradation efficiency and hydrolysis rate of KW decreased while the pH values and concentrations of total ammonia nitrogen and free ammonia nitrogen were increased. Additionally, PDs lower than PD3 presented better digestion performance, and according to results of organics degradation and kinetics study, it could be suggested that appropriate range of PD in KW beneficial for AD is PD5-PD4.
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| 9. |
- Li, Y., et al.
(författare)
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Effects of thermal pretreatment on degradation kinetics of organics during kitchen waste anaerobic digestion
- 2017
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Ingår i: Energy. - : Elsevier BV. - 0360-5442 .- 1873-6785. ; 118, s. 377-386
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Tidskriftsartikel (refereegranskat)abstract
- The influence of thermal pretreatment on degradation properties of organics in kitchen waste (KW) was investigated. The kinetics results showed that thermal pretreatment could enhance the degradation efficiency of crude protein (CP), fat, oil and grease (FOG), volatile solid (VS) and volatile fatty acids (VFA). Thermal pretreatment showed no significant difference in the final concentration of protein but could decrease the FOG degradation potential (7–36%), while increased the lag phase for degradation of protein and FOG respectively by 35–65% and 11–82% compared with untreated KW. Cumulative biogas yield increased linearly and exponentially with the removal efficiency of VS and other organics (CP and FOG) respectively. Additionally, the reduction of CP increased exponentially with FOG removal efficiency. The calculating methods of biogas yield, organics reduction and corresponding appropriate digestion retention based on FOG and CP reduction amount and pretreatment parameters were suggested.
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| 10. |
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