•Simultaneous ammonia and nitrate removal was achieved in one airlift reactor.•DNRA and sulfate reduction were inhibited by intermittent aeration treatment.•Denitrification rate was improved by ...aeration compared with anoxic condition.•Heterotrophic nitrification was considered a potential ammonia metabolic pathway.
In this study, an airlift inner-loop sequencing batch reactor using poly(butylene succinate) as the biofilm carrier and carbon source was operated under an alternant aerobic/anoxic strategy for nitrogen removal in recirculating aquaculture system. The average TAN and nitrate removal rates of 47.35±15.62gNH4–Nm−3d−1 and 0.64±0.14kgNO3–Nm−3d−1 were achieved with no obvious nitrite accumulation (0.70±0.76mg/L) and the dissolved organic carbon in effluents was maintained at 148.38±39.06mg/L. Besides, the activities of dissimilatory nitrate reduction to ammonium and sulfate reduction activities were successfully inhibited. The proteome KEGG analysis illustrated that ammonia might be removed through heterotrophic nitrification, while the activities of nitrate and nitrite reductases were enhanced through aeration treatment. The microbial community analysis revealed that denitrifiers of Azoarcus and Simplicispira occupied the dominate abundance which accounted for the high nitrate removal performance. Overall, this study broadened our understanding of simultaneous nitrification and denitrification using biodegradable material as biofilm carrier.
The ever‐growing demands for electrical energy storage have stimulated the pursuit of alternative advanced batteries. Zn‐ion batteries (ZIBs) are receiving increased attentions due to the low cost, ...high safety, and high eco‐efficiency. However, it is still a big challenge to develop suitable cathode materials for intercalation of Zn ions. This review provides a timely access for researchers to the recent activities regarding ZIBs. First, cathode materials including various manganese oxides, vanadium compounds, and Prussian blue analogs are summarized with details in crystal structures and Zn ion storage mechanisms. Then, the electrolytes and their influences on the electrochemical processes are discussed. Finally, opinions on the current challenge of ZIBs and perspective to future research directions are provided.
Recent advances in zinc‐ion batteries, especially the cathode materials including Mn‐based, V‐based, and Prussian blue analogs based materials, are comprehensively summarized here. The relationships between crystal structure, reaction mechanism, and electrochemical performance are elaborated.
Many ecosystems are facing strong perturbations such as nitrogen (N) fertilization, which can greatly alter ecosystem stability via different mechanisms. Understanding such mechanisms is critical for ...predicting how ecosystems will function in the face of global changes.
We examined how 8 yr of N fertilization with different N rates (no N addition or N addition at a low, medium or high rate) and different forms of N (ammonium, nitrate or ammonium nitrate) affected the temporal stability of the aboveground biomass of an alpine meadow on the Tibetan Plateau, and tested four mechanisms (diversity effect, mean-variance scaling, compensatory dynamics and dominance effect) that may alter stability.
Compared with the control (no N addition), a high N rate did not affect the diversity effect, the mean-variance scaling or the dominance effect, but significantly decreased compensatory dynamics among species and functional groups, which contributed to the reduction in community stability of the alpine meadow. The form of N did not affect any of the four mechanisms and thus did not affect community stability.
A high N rate can change community stability by altering compensatory dynamics, whereas the form of N may not have an effect.
•PBS polymer showed well performance for real RAS wastewater denitrification.•High nitrate loading was favor to inhibit sulfate reduction and DNRA activity.•Variation in microbial population was ...responsible for changed reactor performance.•Precise carbon release was crucial for RAS denitrification process in practice.
Nitrate removal is essential for the sustainable operation of recirculating aquaculture system (RAS). This study evaluated the heterotrophic denitrification using poly(butylene succinate) as carbon source and biofilm carrier for RAS wastewater treatment. The effect of varied operational conditions (influent type, salinity and nitrate loading) on reactor performance and microbial community was investigated. The high denitrification rates of 0.53±0.19kgNO3−-Nm−3d−1 (salinity, 0‰) and 0.66±0.12kgNO3−-Nm−3d−1 (salinity, 25‰) were achieved, and nitrite concentration was maintained below 1mg/L. In addition, the existence of salinity exhibited more stable nitrate removal efficiency, but caused adverse effects such as excessive effluent dissolved organic carbon (DOC) and dissimilation nitrate reduce to ammonia (DNRA) activity. The degradation of PBS was further confirmed by SEM and FTIR analysis. Illumina sequencing revealed the abundance and species changes of functional denitrification and degradation microflora which might be the primary cause of varied reactor performance.
•This paper provides a systematic review of researches on FMEA improvement.•A set of 236 journal articles published between 1998 and 2018 was identified.•Bibliometric analysis was conducted to ...provide insights into the research theme.•Research gaps and opportunities on the improvement of FMEA are identified.
Failure mode and effects analysis (FMEA) is a reliability management technique commonly utilized in various industries to guarantee the security and reliability of systems, services and projects. Nonetheless, the classical risk priority number (RPN) method has been criticized for many inherent deficiencies in the literature. Over the last decades, plenty of models and approaches have been employed to enhance the inherent characteristics of FMEA, but few contributions are devoted to review and summarize the related researches on FMEA improvement. Therefore, this paper aims to conduct a systematic review of the journal articles on the topic during the years between 1998 and 2018. A metadata statistical analysis is undertaken to present an overview of publication distribution across time and journals. Besides, a bibliometric analysis is performed to identify the most influential authors, institutions and areas, reveal the research hotspots and give an insight into the theme evolution in this field. The results indicated that the annual publications on FMEA improvement are rising quickly in the past two decades, especially after 2013; Liu HC, Chang KH, Kumar D, Sharma RK and You JX are the most prolific researchers; and Asian especially China is the major contributor in this field. Moreover, “healthcare failure mode”, “risk ranking”, “extended FMEA”, “gray theory”, “risk evaluation”, and “fuzzy inference” are the research focuses in improving the traditional FMEA.
Soil organic matter (SOM) is a key index of soil fertility. Calculating spectral index and screening characteristic band reduce redundancy information of hyperspectral data, and improve the accuracy ...of SOM prediction. This study aimed to compare the improvement of model accuracy by spectral index and characteristic band. This study collected 178 samples of topsoil (0-20 cm) in the central plain of Jiangsu, East China. Firstly, visible and near-infrared (VNIR, 350-2500 nm) reflectance spectra were measured using ASD FieldSpec 4 Std-Res spectral radiometer in the laboratory, and inverse-log reflectance (LR), continuum removal (CR), first-order derivative reflectance (FDR) were applied to transform the original reflectance (R). Secondly, optimal spectral indexes (including deviation of arch, difference index, ratio index, and normalized difference index) were calculated from each type of VNIR spectra. Characteristic bands were selected from each type of spectra by the competitive adaptive reweighted sampling (CARS) algorithm, respectively. Thirdly, SOM prediction models were established based on random forest (RF), support vector regression (SVR), deep neural networks (DNN) and partial least squares regression (PLSR) methods using optimal spectral indexes, denoted here as SI-based models. Meanwhile, SOM prediction models were established using characteristic wavelengths, denoted here as CARS-based models. Finally, this research compared and assessed accuracy of SI-based models and CARS-based models, and selected optimal model. Results showed: (1) The correlation between optimal spectral indexes and SOM was enhanced, with absolute value of correlation coefficient between 0.66 and 0.83. The SI-based models predicted SOM content accurately, with the coefficient of determination (R2) and root mean square error (RMSE) values ranging from 0.80 to 0.87, 2.40 g/kg to 2.88 g/kg in validation sets, and relative percent deviation (RPD) value between 2.14 and 2.52. (2) The accuracy of CARS-based models differed with models and spectral transformations. For all spectral transformations, PLSR and SVR combined with CARS displayed the best prediction (R2 and RMSE values ranged from 0.87 to 0.92, 1.91 g/kg to 2.56 g/kg in validation sets, and RPD value ranged from 2.41 to 3.23). For FDR and CR spectra, DNN and RF models achieved more accuracy (R2 and RMSE values ranged from 0.69 to 0.91, 1.90 g/kg to 3.57 g/kg in validation sets, and RPD value ranged from 1.73 to 3.25) than LR and R spectra (R2 and RMSE values from 0.20 to 0.35, 5.08 g/kg to 6.44 g/kg in validation sets, and RPD value ranged from 0.96 to 1.21). (3) Overall, the accuracy of SI-based models was slightly lower than that of CARS-based models. But spectral index had a good adaptability to the models, and each SI-based model displayed the similar accuracy. For different spectra, the accuracy of CARS-based model differed from modeling methods. (4) The optimal CARS-based model was model CARS-CR-SVR (R2 and RMSE: 0.92 and 1.91 g/kg in validation set, RPD: 3.23). The optimal SI-based model was model SI3-SVR (R2 and RMSE: 0.87 and 2.40 g/kg in validation set, RPD: 2.57) and model SI-SVR (R2 and RMSE: 0.84 and 2.63 g/kg in validation set, RPD: 2.35).
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Rapeseed (Brassica napus) is the second most important oilseed crop in the world but the genetic diversity underlying its massive phenotypic variations remains largely unexplored. Here, we report the ...sequencing, de novo assembly and annotation of eight B. napus accessions. Using pan-genome comparative analysis, millions of small variations and 77.2-149.6 megabase presence and absence variations (PAVs) were identified. More than 9.4% of the genes contained large-effect mutations or structural variations. PAV-based genome-wide association study (PAV-GWAS) directly identified causal structural variations for silique length, seed weight and flowering time in a nested association mapping population with ZS11 (reference line) as the donor, which were not detected by single-nucleotide polymorphisms-based GWAS (SNP-GWAS), demonstrating that PAV-GWAS was complementary to SNP-GWAS in identifying associations to traits. Further analysis showed that PAVs in three FLOWERING LOCUS C genes were closely related to flowering time and ecotype differentiation. This study provides resources to support a better understanding of the genome architecture and acceleration of the genetic improvement of B. napus.
Using phonons to simulate an optical two-level laser action has been the focus of research. We theoretically study phonon laser in a cavity magnomechanical system, which consist of a microwave ...cavity, a sphere of magnetic material and a uniform external bias magnetic field. This system can realize the phonon-magnon coupling and the cavity photon-magnon coupling via magnetostrictive interaction and magnetic dipole interaction respectively, the magnons are driven directly by a strong microwave field simultaneously. Frist, the intensity of driving magnetic field which can reach the threshold condition of phonon laser is given. Then, we demonstrate that the adjustable external magnetic field can be used as a good control method to the phonon laser. Compared with phonon laser in optomechanical systems, our scheme brings a new degree of freedom of manipulation. Finally, with the experimentally feasible parameters, threshold power in our scheme is close to the case of optomechanical systems. Our study may inspire the field of magnetically controlled phonon lasers.
Quantum gravity corrections have been speculated to lead to modifications to space-time geometry near black-hole horizons. Such structures may reflect gravitational waves, causing echoes that follow ...the main gravitational waves from binary black-hole coalescence. By studying two phenomenological models of the near-horizon structures under the Schwarzschild approximation, we show that such echoes, if they exist, will give rise to a stochastic gravitational-wave background, which is very substantial if the near-horizon structure has a near-unity reflectivity for gravitational waves, readily detectable by Advanced LIGO. In case the reflectivity is much less than unity, the background will mainly be arising from the first echo, with a level proportional to the power reflectivity of the near-horizon structure, but robust against uncertainties in the location and the shape of the structure-as long as it is localized and close to the horizon. Sensitivity of third-generation detectors allows the detection of a background that corresponds to power reflectivity ∼3×10^{-3}, if uncertainties in the binary black-hole merger rate can be removed. We note that the echoes do alter the f^{2/3} power law of the background spectra at low frequencies, which is rather robust against uncertainties.
Cellular reprogramming forcing the expression of pluripotency markers can reverse aging of cells, but how molecular mechanisms through which reprogrammed cells alter aging‐related cellular activities ...still remains largely unclear. In this study, we reprogrammed human synovial fluid‐derived mesenchymal stem cells (MSCs) into induced pluripotent stem cells (iPSCs) using six reprogramming factors and reverted the iPSCs back to MSCs, as an approach to cell rejuvenation. Using the parental and reprogrammed MSCs as control nonrejuvenated and rejuvenated cells, respectively, for comparative analysis, we found that aging‐related activities were greatly reduced in reprogrammed MSCs compared with those in their parental lines, indicating reversal of cell aging. Global transcriptome analysis revealed differences in activities of regulatory networks associated with inflammation and proliferation. Mechanistically, we demonstrated that, compared with control cells, the expression of GATA binding protein 6 (GATA6) in reprogrammed cells was attenuated, resulting in an increase in the activity of sonic hedgehog signaling and the expression level of downstream forkhead box P1 (FOXP1), in turn ameliorating cellular hallmarks of aging. Lower levels of GATA6 expression were also found in cells harvested from younger mice or lower passage cultures. Our findings suggest that GATA6 is a critical regulator increased in aged MSCs that controls the downstream sonic hedgehog signaling and FOXP1 pathway to modulate cellular senescence and aging‐related activities.
The schema summarizes the GATA6/SHH/FOXP1 mechanism that controls aging‐related changes of biological activities in human mesenchymal stem cells. The reduction of GATA6 expression induced by cellular reprogramming results in an increase in the activity of SHH signaling and FOXP1 expression, which in turn attenuates p53/p21CIP1 activity, increases proliferation, autophagic activity, and mitochondrial polarization, and promotes chondrogenic/osteogenic differentiation.
PDF
