• Energy Research
• 2021-2025close
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• Chinese Academy of Sciences close

The leafy seadragon certainly is among evolution's most "beautiful and wonderful" species aptly named for its extraordinary camouflage mimicking its coastal seaweed habitat. However, limited information is known about the genetic basis of its phenotypes and conspicuous camouflage. Here, we revealed genomic signatures of rapid evolution and positive selection in core genes related to its camouflage, which allowed us to predict population dynamics for this species. Comparative genomic analysis revealed that seadragons have the smallest olfactory repertoires among all ray-finned fishes, suggesting adaptations to the highly specialized habitat. Other positively selected and rapidly evolving genes that serve in bone development and coloration are highly expressed in the leaf-like appendages, supporting a recent adaptive shift in camouflage appendage formation. Knock-out of bmp6 results in dysplastic intermuscular bones with a significantly reduced number in zebrafish, implying its important function in bone formation. Global climate change-induced loss of seagrass beds now severely threatens the continued existence of this enigmatic species. The leafy seadragon has a historically small population size likely due to its specific habitat requirements that further exacerbate its vulnerability to climate change. Therefore, taking climate change-induced range shifts into account while developing future protection strategies.

Response of aquatic organisms to eutrophication have been well reported, while less studies are available for the recovery of eutrophic lakes following a reduction in the external loading, especially for systems where nitrogen is reduced but the phosphorus concentration is maintained high due to internal loading. Diatoms are nitrate (NO3-N) opportunists but can also use ammonium (NH4-N). They may, therefore, be more sensitive to nitrogen reduction than other algae that typically prefer NH4-N. We document the variations of nutrients and diatoms in subtropical, eutrophic Lake Taihu over 28 yr during which a reduction of the external loading resulted from lake management. According to the results of change point analysis, data on environmental variables were divided into two periods (P1: 1992-2006; P2: 2007-2019) with two different seasons (WS: Winter-Spring; SA: Summer-Autumn), respectively. Compared with P1-WS, the concentration of NH4-N decreased significantly whereas NO3-N showed no significant change in P2-WS. In contrast, NH4-N concentrations were low and showed no significant changes in P1-SA and P2-SA and NO3-N decreased significantly in the latter period. Accordingly, NO3-N: NH4-N mass ratios in P1-SA and P2-WS were all significantly higher than those in P2-SA and P1-WS, respectively. The biomass of WS diatom increased significantly and the timing of the peak biomass shifted from P1-SA to P2-WS since 2007. The SEM analysis showed that NO3-N was retained as a statistically significant predictor for diatom biomass in P1-SA and significant effects of windspeed, zooplankton and NH4-N on diatom biomass in P2-WS. Windspeed and zooplankton have further changed the biomass of diatoms in the case of declining inorganic nitrogen. We conclude that the magnitude of vernal suppression or stimulation of diatom assemblages has increased, concomitant with the variations of NH4-N and NO3-N: NH4-N mass ratios. Diatoms response to NH4-N or NO3-N is apparently changing in response to water temperature in this eutrophic shallow lake. Thus, parallel reductions in external nitrogen loading, along with variations in dominant inorganic nitrogen, will stimulate the growth of diatom and therefore increase the total biomass of phytoplankton in still high internal phosphorus loading, which is should be regarded as a good sign of restoration measures.

The clustered regularly interspaced short palindromic repeats/CRISPR-associated protein (CRISPR/Cas9) system is a powerful genome editing tool that has been successfully established in some filamentous fungi due to its high flexibility and efficiency. However, the potential toxicity of Cas9 restricts the further popularization and application of this system to some degree. The AMA1 element is a self-replicator derived from Aspergillus nidulans, and its derived vectors can be readily lost without selection. In this study, we eliminated Cas9 toxicity to Fusarium venenatum TB01 based on 100% AMA1-based Cas9 expression vector loss. Meanwhile, two available endogenous Pol III promoters (FvU6374 and Fv5SrRNA) used for sgRNA expression of the CRISPR/Cas9 system were excavated. Compared to FvU6374 (40-50%), Fv5SrRNA exhibited higher single-gene editing efficiency (> 85%), and the efficiency of simultaneous editing of the two genes using Fv5SrRNA was over 75%. Based on this system, a butanediol dehydrogenase encoding gene FvBDH was deleted, and the ethanol yield in variants increased by 52% compared with that of the wild-type. The highly efficient CRISPR/Cas9 system developed here lays the technical foundation for advancing the development of F. venenatum TB01 through metabolic engineering, and the obtained FvBDH gene-edited variants have the potential to simultaneously produce mycoprotein and ethanol by further gene modification and fermentation process optimization in the future.Key points• Cas9 toxicity disappeared and DNA-free gene-edited strains obtained after vector loss• Promoter Fv5SrRNA conferred TB01 higher gene editing efficiency than FvU6374•Deletion of the FvBDH gene resulted in a 52% increase in ethanol yield.

Abstract The mesophase pitch derived graphite foams with low bulk density (L-GF) and high bulk density (H-GF) were spontaneously infiltrated by erythritol to prepare graphite foam/erythritol (GF/erythritol) phase change materials (PCMs) with ultrahigh thermal conductivity for medium temperature thermal energy storage applications. Results of thermophysical properties indicated that thermal diffusivity of the GF/erythritol PCMs can be enhanced by 66 and 117 times as compared with that of pristine erythritol in solid (0.36 mm2/s). This enhancement resulting from three-dimensional ordered network of graphite foam can significantly reduce the charging and discharging time of the PCM storage system. Although H-GF as a matrix can obtain a higher thermal conductivity (68.71 W/(m·K)) than L-GF (40.52 W/(m·K)), the smaller porosity cannot allow more erythritol to be absorbed, and its melting enthalpy (178.4 J/g) is lower than L-GF (266.6 J/g). In addition, the enhancement of thermal conductivity and the increase of interfacial surface area caused by graphite foam structure strongly suppresses the supercooling of erythritol, which can be reduced from 86.0 °C to 53.2 °C. The obtained results demonstrated that the GF/erythritol PCM as a stable PCM is a promising material for medium temperature thermal energy storage applications.

Abstract Based on the design concept of a fourth-generation smart pipe network system, this paper innovatively proposes a new TOTS (Two-supply/One-return, triple pipe structure) arrangement method for district heating systems. Moreover, to accurately predict the heat loss due to the pipeline operation of the multi-pipe system, based on the multipole calculation method, a new heat loss theoretical analytical model for the TOTS was created; additionally, a corresponding three-dimensional numerical simulation model was established, which was analyzed and numerically solved. The results showed that in comparison with thermal loss data measured by Danfoss et al., the above analytical and numerical models have a high accuracy, and the deviation is within 2%. Additionally, through calculations, it was found that the distance between the heating pipes is an important factor that affects the total heat loss from the new multi-control heating system and the actual heat exchange between pipes.

Abstract Nowadays, lithium-ion battery (LIB) technology provides one of the most important approaches for large-scale electricity storage. In this work, an electrical-thermal-fluidic coupled model is proposed for practical LIB-based energy storage systems (ESSs). The coupled model is established based on the equivalent circuit model (ECM) which describes electrical behavior of LIBs, the airflow turbulent model, and the “single domain of multiple sub-regions” thermal model. Currents and voltages of LIB cells, airflow velocity field and pressure field, and temperature distribution in the whole ESS, can be simulated by the developed full-scale model. Simulation results of a practical commercial LIB ESS (1 MW/2 MWh) in typical frequency regulation operation, including electrical-thermal characteristics represented by currents and heat generation rates of LIBs in the ESS, flow characteristics represented by airflow field and mass flow rate distribution, ambient temperature sensitivity analysis represented by temperature distributions of the ESS initially under 27℃ and 38℃ ambient respectively, are displayed and discussed, exhibiting the capability of the proposed model. The proposed model has been validated by comparing the simulated results with the actual measured data; the reasonably good agreement demonstrates the effectiveness of the proposed model. Therefore, the established model has the potential to provide a feasible and powerful approach or tool to perform multi-physics simulations of practical large-scale LIB ESSs for different functions, including but not limited to detailed temperature evaluations, cooling structure optimization, materials selection, and thermal-safety status evaluating and monitoring.

Crystal engineering coupled with in situ interface engineering built a robust host for large K-ion storage, enabling a long cycle life of nearly 10 000 cycles without obvious capacity degradation.