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Air pollution is a leading environmental health risk factor, and in situ toxicity assessment is urgently needed. Bacteria-based bioassays offer cost-effective and rapid toxicity assessments. However, the application of these bioassays for air toxicity assessment has been challenging, due to the instability of bacterial survival and functionality when directly exposed to air pollutants. Here, we developed an approach employing self-assembly passive colonization hydrogel (SAPCH) for in situ air toxicity assessment. The SAPCH features a core–shell structure, enabling the quantitatively immobilization of bacteria on its shell while continuously provides nutrients from its core. An antimicrobial polyelectrolyte layer between the core and shell confines bacteria to the air–liquid interface, synchronizing bacterial survival with exposure to air pollutants. The SAPCH immobilized a battery of natural and recombinant luminescent bacteria, enabling simultaneous detection of various toxicological endpoints (cytotoxicity, genotoxicity and oxidative stress) of air pollutants within 2 h. Its sensitivity was 3–5 orders of magnitude greater than that of traditional liquid-phase toxicity testing, and successfully evaluating the toxicity of volatile organic compounds and combustion smoke. This study presents a method for in situ, rapid, and economical toxicity assessment of air pollution, making a significant contribution to future air quality monitoring and control.

The internal friction angle is a key parameter in assessing the shear strength of cushion layers in composite subgrades. This study refines the evaluation of the internal friction angle in test pile composite subgrades by utilizing cavity expansion and stress rotation theories. Laboratory calibration tests and field experiments with various cushion layers are conducted to analyze how different thicknesses affect deformation and the internal friction angle during loading. Significant correlations are found between the internal friction angle of sand cushion layers and cone penetration resistance, as well as between the internal friction angle of gravel cushion layers and relative deformation. As the cone penetration resistance increases, so does the internal friction angle of sand cushion layers, which ranges from 27.6° to 34.2° for sand and 32.2° to 42.2° for gravel. For flexible pile composite subgrades, the internal friction angle of sand cushion layers typically falls between 33.0° and 36.6°. In semi-rigid composite subgrades, gravel cushion layers show an internal friction angle ranging from 36.0° to 39.5°, while rigid pile composite subgrades display angles between 37.7° and 40.9°. This research provides both theoretical insights and empirical data to aid in the selection of cushion layers for composite subgrade design.

To investigate the mechanical process that occurs between rocks and tooth hobs, the crushing of sandstone with a tooth hob was simulated using reconstructed multi-mineral mesoscopic numerical models of various grain-sized sandstone samples. When a piece of sandstone is crushed by the tooth of a hob rolling at a constant speed, the resultant reaction forces of the sandstone on the tooth first hinder and then contribute to the rolling of the hob. The absolute value of the longitudinal reaction force is significantly higher than that of the lateral reaction force. Because the tooth was subjected to reaction forces from the sandstone, forces and moments were applied to the hob in order to keep the hob rolling. The applied forces were equal in value and opposite in direction to the reaction forces of the sandstone on the tooth. Three typical curves of the work done by the applied forces and moment were obtained, and the contribution of the applied lateral force and moment to the total work done for crushing sandstones was variable; however, no work was done by the applied longitudinal force. Moreover, the applied longitudinal force and total work were positively correlated with the strength of sandstone samples. The total work, applied forces, and moment increased with the maximum penetration depth of the tooth in the sandstone.

CRISPR–Cas12f nucleases are currently one of the smallest genome editors, exhibiting advantages for efficient delivery via cargo-size-limited adeno-associated virus delivery vehicles. Most characterized Cas12f nucleases recognize similar T-rich protospacer adjacent motifs (PAMs) for DNA targeting, substantially restricting their targeting scope. Here we report the cryogenic electron microscopy structure and engineering of a miniature Clostridium novyiCas12f1 nuclease (CnCas12f1, 497 amino acids) with rare C-rich PAM specificity. Structural characterizations revealed detailed PAM recognition, asymmetric homodimer formation and single guide RNA (sgRNA) association mechanisms. sgRNA engineering transformed CRISPR–CnCas12f1, which initially was incapable of genome targeting in bacteria, into an effective genome editor in human cells. Our results facilitate further understanding of CRISPR–Cas12f1 working mechanism and expand the mini-CRISPR toolbox.

The accuracy of subgrade quality evaluation is important for road safety assessment. Since there is little research work devoted to testing lightweight cellular concrete (LCC) by an ultrasound-based method, the quantitative relation between ultrasonic testing results and the quality of LCC subgrade is not well understood. In this paper, the quality of LCC subgrade was evaluated with respect to compressive strength and crack discrimination. The relation between ultrasonic testing results and LCC quality was explored through indoor tests. Based on the quantitative relation between ultrasonic pulse velocity and compressive strength of LCC, a fitting formula was established. Moreover, after the LCC became cracked, the ultrasonic pulse velocity and ultrasonic pulse amplitude decreased. After determining the lower limiting values of the ultrasonic pulse velocity and ultrasonic pulse amplitude through the statistical data, it could be calculated whether there were cracks in LCC subgrade. The ultrasonic testing results showed that the compressive strength of the LCC subgrade was suitable for purpose and there was no crack in the subgrade. Then core samples were taken from the subgrade. Comparisons between ultrasonic testing results of subgrade and test results of core samples demonstrated a good agreement.

Background: Microglia play a crucial role in regulating the progression of traumatic brain injury (TBI). In specific, microglia can self-activate and secrete various substances that exacerbate or alleviate the neuroimmune response to TBI. In addition, microRNAs (miRNAs) are involved in the functional regulation of microglia. However, molecular markers that reflect the dynamics of TBI have not yet been found in peripheral tissues. Methods: Paired samples of peripheral blood were collected from patients with TBI before and after treatment. Next-generation sequencing and bioinformatics analysis were used to identify the main pathways and biological functions of TBI-related miRNAs in the samples. Moreover, lipopolysaccharide-treated human microglia were used to construct a cellular immune-activation model. This was combined with analysis of peripheral blood samples to screen for highly expressed miRNAs derived from activated microglia after TBI treatment. Quantitative reverse-transcriptase polymerase chain reaction was used to determine the expression levels of these miRNAs, allowing their relationship with the severity of TBI to be examined. Receiver operating characteristic (ROC) curves were constructed to analyse the clinical utility of these miRNAs for determining the extent of TBI. Results: Sequencing results showed that 37 miRNAs were differentially expressed in peripheral blood samples from patients with TBI before and after treatment, with 17 miRNAs being upregulated and 20 miRNAs being downregulated after treatment. The expression profiles of these miRNAs were verified in microglial inflammation models and in the abovementioned peripheral blood samples. The results showed that hsa-miR-122-5p and hsa-miR-193b-3p were highly expressed in the peripheral blood of patients with TBI after treatment and that the expression levels of these miRNAs were correlated with the patients’ scores on the Glasgow Coma Scale. ROC curve analysis revealed that abnormally high levels of expression of hsa-miR-122-5p and hsa-miR-193b-3p in peripheral blood have some clinical utility for distinguishing different extents of TBI and thus could serve as biomarkers of TBI. Conclusion: Abnormally high levels of expression of hsa-miR-122-5p and hsa-miR-193b-3p in the peripheral blood of patients with TBI were due to the activation of microglia and correlated with the severity of TBI. This discovery may help to increase understanding of the molecular pathology of TBI and guide the development of new strategies for TBI therapy based on microglial function.

This paper proposed a 5.6 kW 11.7 kW/kg four-phase interleaved buck converter (FPIBC) for the unmanned aerial vehicle (UAV) low-voltage power system. The UAV mainly concerns the lightweight strategy and the power density of the DC-DC converter. We proposed a comprehensive lightweight strategy with the characteristics of reduced inductor current ripples, small size of filter inductors and capacitors, and high output power. The output current ripples are reduced by using interleaved modulation strategy and integrated CLC filters cascaded to the input side and output side respectively. In addition, the aluminum based printed circuit board (PCB) is used with SMD power transistors to obtain better heat dissipation capability without fans. With abovementioned methods, the designed DC-DC converter has a power of 5.6 kW @ 0.48 kg, the power-to-weight ratio is improved to be 11.7 kW/kg, and the power density is 3 W/cm3. The efficiency of this DC-DC converter is up to 95.8%.

During the construction of lightweight cellular concrete (LCC), material damage frequently occurs, causing the degradation and deterioration of the mechanical performance, durability, and subgrade quality of LCC. The construction-induced damage can be more significant than those from the service environment of LCC, such as freeze-thaw (F—T) action in cold regions. However, the effect of construction-induced damage on LCC during F—T cycles is often ignored and the deterioration mechanisms are not yet clarified. In this study, we investigated the factors causing damage during construction using a sample preparation method established to simulate the damage in the laboratory setting. We conducted F—T cycle tests and microstructural characterization to study the effect of microstructural damage on the overall strength of LCC with different water contents under F—T actions. We established the relationship between the pore-area ratio and F—T cycle times, pore-area ratio, and strength, as well as the F—T cycle times and strength under different damage forms. The damage evolution is provided with the rationality of the damage equation, verified by comparing the measured and predicted damage variables. This study would serve as a guide for the construction and performance of LCC in cold regions.