Search

In this study, the structure and antifreeze activity of surimi by-product protein hydrolysate (SBPH) were investigated, and the cryoprotective effect and mechanism on Streptococcus thermophilus were explored by measuring its growth performance, malondialdehyde (MDA) content, protease activity, metabolic activity and membrane potential after freezing treatment. The results showed that the molecular mass range of SBPH was 260–2 550 Da, and a total of 78 peptides with 8–18 amino residues were identified from SBPH, some of which had the characteristic structure of tripeptide repeat sequences imparting high antifreeze activity to SBPH (thermal hysteresis activity of 1.76 ℃). Compared with other antifreeze agents (sucrose, skim milk and glycerol), SBPH (2 mg/mL) enhanced the cell viability, growth activity and acid production of S. thermophilus after freezing treatment, attenuated oxidative stress damage to cells caused by low temperature, significantly inhibited the decrease in the relevant protease activity (P < 0.05), increased the metabolic activity of cells, and attenuated the hyperpolarization of the cell membrane thereby contributing to maintaining the integrity and fluidity of the cell membrane. SBPH could maintain the interaction between phospholipid bilayers to some extent and protect the structure of the cell membrane. In conclusion, SBPH can protect the function and integrity of cells, and reduce cryogenic damage to cells to a certain extent.

The present study was aimed to obtain a close insight into the distribution and diversity of antibiotic-resistant bacteria (ARB) and antibiotic-resistance genes (ARGs) among the aquatic products collected in Zhejiang, China. A total of 136 presumptive ARB picked up from six aquatic samples were classified into 22 genera and 49 species based on the 16S rDNA sequencing. Aeromonas spp., Shewanella spp., Acinetobacter spp., Myroides spp., Pseudomonas spp., and Citrobacter spp. accounted for 80% of the ARB. Among them, 109 isolates (80.15%) exhibited resistance to at least one antibiotic. Most isolates showed resistance to not only the originally selected drug but also to one to three other tested drugs. The diversity of ARB distributed in different aquatic products was significant. Furthermore, the resistance data obtained from genotypic tests were not entirely consistent with the results of the phenotypic evaluation. The genes qnrS, tetA, floR, and cmlA were frequently detected in their corresponding phenotypic resistant isolates. In contrast, the genes sul2, aac(6’)-Ib, and blaPSE were less frequently found in the corresponding phenotypically resistant strains. The high diversity and detection rate of ARB and ARGs in aquaculture might be a significant threat to the food chains closely related to human health.

Blackbody‐sensitive uncooled infrared photodetectors with ultra‐broadband and ultrafast photoresponse have a profound impact on many areas of modern science and technology. However, it is a big challenge for both traditional photodetectors and emerging low‐dimensional ones to simultaneously have all the above characteristics. Here, this challenge is addressed by establishing a Te/WTe2 heterostructure photodetector. The built‐in field of the heterostructure and the crossing conduction and valence bands of WTe2 jointly result in a high responsivity and a visible‐to‐long‐wavelength‐infrared photoresponse range. The peak responsivity (at the 3.3 µm wavelength) reaches 914 mA W−1 at zero bias and 8.51 A W−1 at 2 V bias. Further, the joint action coupled with the high mobility of Te and WTe2 promotes the 3‐dB bandwidth to 153 kHz. The self‐powered blackbody responsivity and specific detectivity reach 235.7 mA W−1 and 1.1 × 108 cm Hz1/2 W−1, respectively. The former increases to 5.82 A W−1 at 1 V bias. Moreover, this device is polarization‐sensitive with a contrast ratio of 2. This work reveals the potential of the Te/WTe2 heterostructure for high‐performance room‐temperature infrared photodetectors. [ABSTRACT FROM AUTHOR]

Inverted NiOx‐based perovskite solar cells (PSCs) exhibit considerable potential because of their low‐temperature processing and outstanding excellent stability, while is challenged by the carriers transfer at buried interface owing to the inherent low carrier mobility and abundant surface defects that directly deteriorates the overall device fill factor. Present work demonstrates a chemical linker with the capability of simultaneously grasping NiOx and perovskite crystals by forming a Ni−S−Pb bridge at buried interface to significantly boost the carriers transfer, based on a rationally selected molecule of 1,3‐dimethyl‐benzoimidazol‐2‐thione (NCS). The constructed buried interface not only reduces the pinholes and needle‐like residual PbI2 at the buried interface, but also deepens the work function and valence band maximum positions of NiOx, resulting in a smaller VBM offset between NiOx and perovskite film. Consequently, the modulated PSCs achieved a high fill factor up to 86.24 %, which is as far as we know the highest value in records of NiOx‐based inverted PSCs. The NCS custom‐tailored PSCs and minimodules (active area of 18 cm2) exhibited a champion efficiency of 25.05 % and 21.16 %, respectively. The unencapsulated devices remains over 90 % of their initial efficiency at maximum power point under continuous illumination for 1700 hours. [ABSTRACT FROM AUTHOR]

Distributed drive electric vehicles improve steering response and enhance overall vehicle stability by independently controlling each motor. This paper introduces a control framework based on Adaptive Model Predictive Control (AMPC) for coordinating handling stability, consisting of three layers: the dynamic supervision layer, online optimization layer, and low-level control layer. The dynamic supervision layer considers the yaw rate and maneuverability limits when establishing the β − β ˙ phase plane stability boundary and designs variable weight factors based on this stability boundary. The online optimization layer constructs the target weight-adaptive AMPC strategy, which can adjust the control weights for maneuverability and lateral stability in real time based on the variable weight factors provided by the dynamic supervision layer. The low-level control layer precisely allocates the driver's requested driving force and additional yaw moment by using torque distribution error and tire utilization as the cost function. Finally, experiments are conducted on a Simulink-CarSim co-simulation platform to assess the performance of AMPC. Simulation results show that, compared to the traditional MPC strategy, this control strategy not only enhances maneuverability under normal conditions but also improves lateral stability control under extreme conditions. [ABSTRACT FROM AUTHOR]

Providing safe, smooth, and efficient trajectories for autonomous vehicles has long been a question of great interest in the field of autopiloting. In dynamic and ever-changing urban environments, safe and efficient trajectory planning is fundamental to achieving autonomous driving. Nevertheless, the complexity of environments with multiple constraints poses challenges for trajectory planning. It is possible that behavior planners may not successfully obtain collision-free trajectories in complex urban environments. Herein, this paper introduces spatio–temporal joint optimization-based trajectory planning (SJOTP) with multi-constraints for complex urban environments. The behavior planner generates initial trajectory clusters based on the current state of the vehicle, and a topology-guided hybrid A* algorithm applied to an inflated map is utilized to address the risk of collisions between the initial trajectories and static obstacles. Taking into consideration obstacles, road surface adhesion coefficients, and vehicle dynamics constraints, multi-constraint multi-objective coordinated trajectory planning is conducted, using both differential-flatness vehicle models and point-mass vehicle models. Taking into consideration longitudinal and lateral coupling in trajectory optimization, a spatio–temporal joint optimization solver is used to obtain the optimal trajectory. The simulation verification was conducted on a multi-agent simulation platform. The results demonstrate that this methodology can obtain optimal trajectories safely and efficiently in complex urban environments. [ABSTRACT FROM AUTHOR]

For models with large numerical simulation costs, such as high-speed trains, using as few samples as possible to construct a high-precision surrogate model during aerodynamic multi-objective optimization is critical to improving optimization efficiency. This study proposes a sequential infill criterion (SIC) appropriate for the Kriging surrogate model to address this issue. Three multi-objective functions are employed to test the feasibility of constructing a surrogate model based on SIC, and the SIC surrogate model then performs multi-objective aerodynamic optimizations on the high-speed train. The findings indicate that the expected improvement infill criterion (EIC) in the first stage can enhance the global prediction accuracy of the SIC. An infill criterion based on EIC that fuses gradient information (PGEIC) in the second stage is proposed to seek samples in the Pareto front. The PGEIC surrogate model achieves the lowest generational distance and prediction error. The performance of EIC for global search, EIC for Pareto front search, and infill criterion for Pareto front search using only gradient information is poor. The final PGEIC–SIC surrogate model of train aerodynamics has less than 1% prediction error for the three optimization objectives. The optimal solution reduces the aerodynamic drag force of the head car and the aerodynamic drag and lift force of the tail car by 4.15%, 3.21%, and 3.56%, respectively, compared with the original model. Furthermore, sensitivity analysis of key parameters revealed that the nose height v1, cab window height v3, and lower contour line have a greater impact on aerodynamic forces. Moreover, the nose and cab window heights of the optimal model have been reduced, and the lower contour line is concave. Correspondingly, the streamlined shape appears more rounded and slender. [ABSTRACT FROM AUTHOR]

Wide-band gap (≥1.66 eV) inverted perovskite solar cells (PSCs) are important portions of tandem silicon/PSCs. However, the poor efficiency and phase stability are still unresolved and blocking the industrialization of the scalable inverted PSCs. An interface modification strategy was developed using a multifunctional molecule, pyridinyl–benzimidazolium chloride to stabilize the perovskite surface. The pyridine and benzimidazole groups can fulfill halide vacancies, saturate the uncoordinated Pb2+ sites, and bond with formamidinium/methylammonium cations. Benefitting from the interface defect passivation, reduced nonradiative recombination, and effective suppression of halide phase separation, a champion efficiency of 21.82% with a high Voc of 1.24 V in the fabricated inverted-small-area PSCs was achieved at the 1.67 eV-bandgap perovskite. The unsealed PSCs presented high light stability and excellent storage stability of over 2000 h. The semitransparent mini-modules were also successfully fabricated with high efficiency of 18.05% at a 1.92 cm2 active area. This multifunctional defect passivation strategy provides an important avenue for high-performance perovskite top cells for tandem photovoltaics. [ABSTRACT FROM AUTHOR]