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Unmanned aerial vehicle (UAV) has great application prospect because of its capability of three-dimensional space operation. The reliability of attitude and heading reference system (AHRS) for UAV attitude estimation is crucial for the application of UAV. When a UAV is subjected to unknown electromagnetic interference and force interference in flight, its attitude detection system can suffer from reduced accuracy or even failure. In this paper, a fuzzy adaptive complementary filter (CF) for attitude estimation based on norm judgment is proposed to solve the problem that the sensor is easily disturbed by the complex flight environment and the fixed filter parameters are difficult to obtain the UAV attitude accurately under different flight states. Firstly, the correction model of the gyroscope, which includes four filter parameters, namely accelerometer weight, magnetometer weight, proportional gain P and integral gain I, is established. Secondly, the influence of the four parameters on the estimation accuracy is analyzed. Finally, the adaptive adjustment rules are designed to adjust the filter parameters online and thus achieve the accurate and reliable measurement of UAV attitude. The feasibility of the proposed algorithm is verified through static, dynamic and interference experiments with the specially designed AHRS test platform. And the results show that the attitude estimation algorithm designed in this paper can ensure the high accuracy of the system in both steady state and high-speed rotation, shield the pitch and roll angles from the acceleration of motion, and keep the yaw angle from the external magnetic field.

IntroductionNitrogen (N) and phosphorus (P) enrichment due to anthropogenic activities can significantly affect soil N transformations in forest ecosystems. However, the effects of N and P additions on nitrification and denitrification processes in Metasequoia glyptostroboides plantations, and economically important forest type in China, remain poorly understood.MethodsThis study investigated the responses of soil nitrification and denitrification rates, as well as the abundances of nitrifiers and denitrifiers, to different levels of N and P additions in a 6-year nutrient addition experiment in a M. glyptostroboides plantation.ResultsStepwise multiple regression analysis was used to identify the main predictors of nitrification and denitrification rates. The results showed that moderate N addition (N2 treatment, 2.4 mol·m-2) stimulated nitrification rates and abundances of ammonia-oxidizing archaea (AOA) and bacteria (AOB), while excessive N and P additions inhibited denitrification rates and reduced the abundance of nirS-type denitrifiers. AOB abundance was the main predictor of nitrification rates under N additions, whereas microbial biomass carbon and nirS gene abundance were the key factors controlling denitrification rates. Under P additions, tree growth parameters (diameter at breast height and crown base height) and AOB abundance were the primary predictors of nitrification and denitrification rates.DiscussionOur study reveals complex interactions among nutrient inputs, plant growth, soil properties, and microbial communities in regulating soil N transformations in plantation forests. This study also offers valuable insights for formulating effective nutrient management strategies to enhance the growth and health of M. glyptostroboides plantations under scenarios of increasing elevated nutrient deposition.

Abstract Background Bladder cancer (BC) is the most common urinary tract malignancy. Aurora kinase B (AURKB), a component of the chromosomal passenger protein complex, affects chromosomal segregation during cell division. Mitotic arrest-deficient 2-like protein 2 (MAD2L2) interacts with various proteins and contributes to genomic integrity. Both AURKB and MAD2L2 are overexpressed in various human cancers and have synergistic oncogenic effects; therefore, they are regarded as emerging therapeutic targets for cancer. However, the relationship between these factors and the mechanisms underlying their oncogenic activity in BC remains largely unknown. The present study aimed to explore the interactions between AURKB and MAD2L2 and how they affect BC progression via the DNA damage response (DDR) pathway. Methods Bioinformatics was used to analyze the expression, prognostic value, and pro-tumoral function of AURKB in patients with BC. CCK-8 assay, colony-forming assay, flow cytometry, SA-β-gal staining, wound healing assay, and transwell chamber experiments were performed to test the viability, cell cycle progression, senescence, and migration and invasion abilities of BC cells in vitro. A nude mouse xenograft assay was performed to test the tumorigenesis ability of BC cells in vivo. The expression and interaction of proteins and the occurrence of the senescence-associated secretory phenotype were detected using western blot analysis, co-immunoprecipitation assay, and RT-qPCR. Results AURKB was highly expressed and associated with prognosis in patients with BC. AURKB expression was positively correlated with MAD2L2 expression. We confirmed that AURKB interacts with, and modulates the expression of, MAD2L2 in BC cells. AURKB knockdown suppressed the proliferation, migration, and invasion abilities of, and cell cycle progression in, BC cells, inducing senescence in these cells. The effects of AURKB knockdown were rescued by MAD2L2 overexpression in vitro and in vivo. The effects of MAD2L2 knockdown were similar to those of AURKB knockdown. Furthermore, p53 ablation rescued the MAD2L2 knockdown-induced suppression of BC cell proliferation and cell cycle arrest and senescence in BC cells. Conclusions AURKB activates MAD2L2 expression to downregulate the p53 DDR pathway, thereby promoting BC progression. Thus, AURKB may serve as a potential molecular marker and a novel anticancer therapeutic target for BC.

Summary: p53 regulates multiple signaling pathways and maintains cell homeostasis under conditions of DNA damage and oxidative stress. Although USP7 has been shown to promote p53 stability via deubiquitination, the USP7-p53 activation mechanism has remained unclear. Here, we propose that DNA damage induces reactive oxygen species (ROS) production and activates ATM-CHK2, and CHK2 then phosphorylates USP7 at S168 and T231. USP7 phosphorylation is essential for its deubiquitination activity toward p53. USP7 also deubiquitinates CHK2 at K119 and K131, increasing CHK2 stability and creating a positive feedback loop between CHK2 and USP7. Compared to peri-tumor tissues, thyroid cancer and colon cancer tissues show higher CHK2 and phosphorylated USP7 (S168, T231) levels, and these levels are positively correlated. Collectively, our results uncover a phosphorylation-deubiquitination positive feedback loop involving the CHK2-USP7 axis that supports the stabilization of p53 and the maintenance of cell homeostasis.

Lead-free Mn2+-based metal halide materials are now being considered as clean candidates for backlight displays and lights due to the d–d transition, diverse components, and environmental friendliness. Therefore, efficient and stable Mn2+-based metal halide phosphors are in great demand for practical applications. In this work, adopting the mixed-ligand strategy, a series of [(CH3)4N]2−x[(C2H5)4N]xMnCl4 phosphors were synthesized by mechanochemical process. With the increase molar ratio of (CH3)4N/(C2H5)4N, the phase of phosphors is transformed from orthorhombic to tetragonal. Compared to [(CH3)4N]2MnCl4 and [(C2H5)4N]2MnCl4 phosphors, the mixed-ligand strategy significantly boosts the green emission intensity of Mn2+-based metal halide phosphors. The obtained [(CH3)4N][(C2H5)4N]MnCl4 phosphors exhibit a high photoluminescence quantum yield (PLQY) of 83.78% under 450 nm excitation, which is attributed to the modulation of the adjacent [MnCl4]2- distance by using the different chain length of organic cations, effectively suppressing non-radiative recombination. Additionally, the [(CH3)4N][(C2H5)4N]MnCl4 phosphors exhibit a green emission at 516 nm, narrow full width at half-maximum (FWHM) of 45.53 nm, and good thermal stability. The constructed white light-emitting diode (WLED) device exhibits a wide color gamut of 108.3% National Television System Committee, demonstrating the suitability of the [(CH3)4N][(C2H5)4N]MnCl4 phosphors as a green emitter for WLED displays and lightings. This work provides a new way to modulate the PL performance of manganese-based metal halides for application in the optoelectronic field.

Tuberculosis is a worldwide plague caused by the pathogen Mycobacterium tuberculosis (M. tb). Toxin–antitoxin (TA) systems are genetic elements abundantly present in prokaryotic organisms and regulate important cellular processes. MazEF is a TA system implicated in the formation of “persisters cells” of M. tb, which contain more than 10 such members. However, the exact function and inhibition mode of each MazF are not fully understood. Here we report crystal structures of MazF-mt3 in its apo form and in complex with the C-terminal half of MazE-mt3. Structural analysis suggested that two long but disordered β1–β2 loops would interfere with the binding of the cognate MazE-mt3 antitoxin. Similar loops are also present in the MazF-mt1 and -mt9 but are sustainably shortened in other M. tb MazF members, and these TA pairs behave distinctly in terms of their binding modes and their RNase activities. Systematic crystallographic and biochemical studies further revealed that the biochemical activities of M. tb toxins were combined results between the interferences from the characteristic loops and the electrostatic interactions between the cognate TA pairs. This study provides structural insight into the binding mode and the inhibition mechanism of the MazE/F TA pairs, which facilitate the structure-based peptide designs.

Herbaceous plants contribute greatly to plant diversity and play an important role in regulating the structure and functioning of forest ecosystems. Comparing with woody species, herbs exhibit higher sensitivity to seasonal changes from spring-growth to autumn-mortality. Despite extensive research on understory herb diversity (e.g., abundance and richness) in forests, how the underlying mechanisms change across seasons remain unclear, especially in temperate forests. We explored the seasonal dynamics of herb diversity (here abundance and richness) by surveying herbs of 174 quadrats (1 m × 1 m) in a 25-ha (500 m × 500 m) temperate forest in spring, summer, and autumn of 2022, respectively. We examined the effects of overstory trees (diversity, composition, and three-dimensional (3D) structural complexity detected by LiDAR), topography (elevation, slope, and aspect), and microsite conditions (light availability, soil nutrients, and soil water content) on herb diversity in different seasons. We found a similar seasonal pattern for herb abundance and richness, i.e., both decreased from spring to summer and then to autumn, but the driving mechanisms differed remarkably across seasons. Specifically, the importance of overstory trees, topography, and microsite conditions on herb abundance vs. richness varied inversely across seasons. For herb abundance, the importance of overstory trees (primarily 3D structural complexity) increased from spring to autumn, while the importance of topography decreased. Conversely, for herb richness, the importance of overstory trees decreased from spring to autumn, while the importance of topography increased. Microsite conditions governed spatial variations of herb abundance in all seasons but only in autumn for herb richness, with importance of soil nutrients remaining relatively constant while that of soil water content and light availability changed greatly across seasons. Our results demonstrate substantial seasonal variations in driving mechanisms of herb diversity in the temperate forest. These differentiated responses of herb abundance and richness to different drivers across seasons further highlight the significance of considering seasonal variations of the mechanisms underlying understory plant diversity in forest biodiversity conservation.

Phenolic resin pyrolytic carbons were obtained by catalytic pyrolysis of phenolic resin at 500 °C, 600 °C, 700 °C, and 800 °C for 3 h in an argon atmosphere using copper nitrate as a catalyst precursor. The effects of copper salts on the pyrolysis process of phenolic resin as well as the structural evolution and oxidation resistance of phenolic resin pyrolytic carbons were studied. The results showed that copper oxide (CuO) generated from the thermal decomposition of copper nitrate was reduced to copper (Cu) by the gas generated from the thermal decomposition of the phenolic resin. Carbon nanofibers with tapered structures were synthesized by Cu catalysis of pyrolysis gas at 500–800 °C. The catalytic pyrolysis of phenolic resin with Cu increased the graphitization degree and reduced the pore volume of the phenolic resin pyrolytic carbons. The combined action improved the oxidation resistance of phenolic resin pyrolytic carbons.

A novel method is introduced in this study for producing ceramisite coarse aggregates that are both lightweight and possess high strength. The process involves utilizing fly ash as the primary material, along with coal ash floating beads (CAFBs) that have high softening temperature and a spherical hollow structure serving as the template for forming pores. This study examined the impact of varying particle size and quantity of floating beads on the composition and characteristics of ceramisite aggregates. Results showed that the high softening temperature of floating beads provided stability to the spherical cavity structure throughout the sintering process. Furthermore, the pore structure could be effectively tailored by manipulating the size and quantity of the floating beads in the manufacturing procedure. The obtained ceramisite aggregates feature a compact outer shell and a cellular inner core with uniformly distributed pores that are isolated from each other and mostly spherical in form. They achieve a low density ranging from 723 to 855 kg/m3, a high cylinder compressive strength between 8.7 and 13.5 MPa, and minimal water absorption rates of 3.00 to 4.09%. The performance metrics of these coarse aggregates significantly exceeded the parameters specified in GB/T 17431.1-2010 standards.

Nickel-based coatings were prepared by laser cladding assisted with rotating magnetic field on mild steel substrates. The effects of rotating magnetic field on the defects, microstructure, residual stress, microhardness, and wear resistance of the coatings were studied. Results revealed that the rotating magnetic field reduced pores and cracks of the nickel-based coatings. The nickel-based coatings are main composed of γ-(Ni, M), CrB, M23C6, and NbC phases. The average grain size of the coating decreased from 0.67 μm2 to 0.49 μm2 with rotating magnetic field assistance. The number of large-angle grain boundaries was increased too. At the same time, the residual stress in the coating was significantly reduced by the rotating magnetic field. Therefore, the cracking tendency of the coating was reduced. The average microhardness of the nickel-based coating increased from 422.5 HV0.2 to 515.5 HV0.2 due to fine-grain strengthening. The wear mechanisms of the coatings were mix of abrasive wear and adhesive wear. With rotating magnetic field assistance, the wear resistance of the coating was greatly enhanced. The wear rate of the coating reduced 83.7% from 85.2 μm3/(N∗m) to 13.9 μm3/(N∗m). The wear weight loss reduced 87% from 13.8 mg to 1.8 mg.

The non-uniformity of temperature field distribution of long-span steel structure is proportional to the intensity of solar radiation. Based on the background of Guangzhou Baiyun Station large-span complex steel roof structure, this paper studies the non-uniformtemperature field distribution of large-span steel structure under the Summer Solstice daily radiation-thermal-fluid coupling action based on Star-ccm¸ finite element software, and uses Spa2000 software to analyze the stress and deformation of steel roof under temperature action. Combined with the on-site temperature monitoring, the maximum difference with the measured value is 2.5˚C compared with the numerical simulation results, which verifies the validity of the finite element simulation. The results show that: from 8:00, with the increase of solar altitude angle, the intensity of solar radiation increases, the temperature rises, and the temperature distribution of large-span steel structure becomes more and more non-uniform. From14:00 to18:00, the solar radiation weakens, and the temperature distribution tends to be uniform. Finally, reasonable construction suggestions and measures are proposed to reduce the adverse effects of temperature effects, which can provide theoretical references for the safe construction and normal operation of large-span steel structures located in the subtropics.

Bio-degradation of poly(butylene adipate-co-terephthalate) is an attractive tactic but requires an effective hydrolytic enzyme. Here, the authors demonstrate that cutinases are highly potent PBAT-decomposing enzymes and their mechanism is proposed based on substrate-binding mode.

Abstract tRNA-derived fragments (tRFs) are an emerging category of small non-coding RNAs that are generated from cleavage of mature tRNAs or tRNA precursors. The advance in high-throughput sequencing has contributed to the identification of increasing number of tRFs with critical functions in distinct physiological and pathophysiological processes. tRFs can regulate cell viability, differentiation, and homeostasis through multiple mechanisms and are thus considered as critical regulators of human diseases including cancer. In addition, increasing evidence suggest the extracellular tRFs may be utilized as promising diagnostic and prognostic biomarkers for cancer liquid biopsy. In this review, we focus on the biogenesis, classification and modification of tRFs, and summarize the multifaceted functions of tRFs with an emphasis on the current research status and perspectives of tRFs in cancer.

With the rapid development of civil aviation, carbon emissions have brought severe environmental problems. Realizing efficient and sustainable carbon emission reduction is of great significance for achieving green development in civil aviation sector. Therefore, in the process of pursuing civil aviation carbon emission reduction goals, it is necessary to further consider how to achieve emission reduction at the lowest cost. Based on the accurate carbon emission performance evaluation, the carbon abatement cost among different representative airlines have been systematically compared. The main work and findings of this study can be summarized in the following three aspects. Firstly, a new nonparametric shadow price measurement method was constructed based on the Slacks-Based Measurement Data Envelopment Analysis (SBM-DEA). This can better reflect the essence of efficiency evaluation and the calculated shadow price results are more consistent with the real market. Secondly, the average value of carbon emission efficiency has experienced a fluctuating downward trend from 2011 to 2017, indicating that the carbon emission efficiency of global airlines has decreased. Thirdly, the average value of the shadow price is generally between 313.4 and 398.4 dollars/ton, showing an “up-down-up” trend, and reaching a peak of 398.4 dollars/ton in 2014. This can provide a basis for low-carbon policy makers in the civil aviation sector, and also provide reference for different types of airlines to achieve low-cost emission reduction.

WTaNbMo refractory high entropy alloy (RHEA) coatings were prepared by laser cladding assisted with reciprocating dynamic magnetic field on Inconel 718 substrates. The effects of dynamic magnetic field on the microstructure, defects and residual stress were discussed. The results show that the reciprocating magnetic field improves the microstructure homogeneity of the laser cladded WTaNbMo coating. The coatings are composed of WTaNbMo solid solution (BCC) and γ-(Ni, M). With reciprocating magnetic field assistance, the flow in the molten pool is accelerated, porosity is reduced. The residual stress inside the coating is depressed, thereby cracks in the coating are inhibited. The flow behavior in the molten pools was also discussed.

With the rapid development of the underwater Internet of Things (IoT), the number of underwater communication nodes is rapidly increasing. The access capacity of a traditional multi-antenna communication system is limited by the number of transmitting antennas, and multi-beam communication systems using non-orthogonal multiple access (NOMA) technology can enhance the access capacity of the system. However, this can lead to serious inter-beam and intra-beam interference. To address the severe issues of inter-beam and intra-beam interference in underwater multi-beam NOMA systems, we propose an adaptive transmit diversity strategy. We design an algorithm for adaptive selection and merging beams based on the degree of interference between beams in space, which merges LED beams with high interference. Diversity technology is used to reduce interference between beams, and spatial multiplexing is still performed between LED groups with low interference. Within the same beam, we use an OFDM-NOMA scheme to match and group the users. Signals from different user groups are sent through different subcarriers to improve resource utilization. This enhances access capacity while reducing NOMA inter-user interference. Simulation results show that the bit error rate (BER) of users with the adaptive transmit diversity strategy satisfies the forward error correction (FEC) limits in the presence of high inter-beam interference and has a better reachable rate and BER performance compared to the multi-beam access system without interference management. We also analyze the system BER performance of the proposed strategy in the multi-user case, and the BER of all 32 access nodes are lower than the FEC threshold at a communication distance of 5 m. This demonstrates that the strategy can effectively reduce the interference of the multi-beam NOMA system.

Mycoplasma hyopneumoniae is a highly contagious pathogen causing porcine enzootic pneumonia, which elicits prolonged inflammatory response modulated by pattern recognition receptors (PRRs). Although significant advances have been achieved in understanding the Toll-Like receptors that recognize M. hyopneumoniae, the role of nucleotide-binding oligomerization domain 1 (NOD1) in M. hyopneumoniae infected cells remains poorly understood. This study revealed that M. hyopneumoniae activates the NOD1-RIP2 pathway and is co-localized with host NOD1 during infection. siRNA knockdown of NOD1 significantly impaired the TRIF and MYD88 pathway and blocked the activation of TNF-α. In contrast, NOD1 overexpression significantly suppressed M. hyopneumoniae proliferation. Furthermore, we for the first time investigated the interaction between M. hyopneumoniae mhp390 and NOD1 receptor, and the results suggested that mhp390 and NOD1 are possibly involved in the recognition of M. hyopneumoniae. These findings may improve our understanding of the interaction between PRRs and M. hyopneumoniae and the function of NOD1 in host defense against M. hyopneumoniae infection.

Growing evidence has shown the oncogenic function of matrix metallopeptidase 7 (MMP7) in various tumors. However, no systemic pan-cancer analysis on the association between MMP7 and different cancers based on big clinical data is available. TIMER2, GEPIA2, UALCAN, cBioPortal, String, Metascape, and other web databases were searched in the present study. Generally, MMP7 expression is significantly upregulated in most The Cancer Genome Atlas (TCGA) cancer types compared to the paired normal controls, yet is downregulated in tumor tissues of invasive breast carcinoma (BRCA), kidney chromophobe (KICH), kidney renal clear cell carcinoma (KIRC), liver hepatocellular carcinoma (LIHC), and skin cutaneous melanoma (SKCM). MMP7 protein expression is notably higher in the primary tumor tissues of colon cancer, lung adenocarcinoma (LUAD), and uterine corpus endometrial carcinoma (UCEC) than in normal tissues and is significantly lower in the primary tumor tissues of breast cancer, clear cell renal carcinoma, and ovarian cancer. Furthermore, MMP7 expression is strongly associated with pathological stages, clinical outcomes, tumor mutational burden (TMB), and microsatellite instability (TSI). Gene amplification was detected in most TCGA cancer types. In addition, the missense mutation is the primary type of MMP7 genetic alteration in tumors. Significant positive correlations between MMP7 expression and cancer-associated fibroblasts (CAFs) have been demonstrated in most TCGA cancers. MMP7 expression was also found to be positively correlated with infiltration of dendritic cells and macrophages in some specific tumor types. Functional enrichment analysis by the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways and gene ontology (GO) methods revealed that RNA processing and DNA damage checkpoints might reveal the pathogenetic mechanisms of MMP7. This pan-cancer analysis provides a clear panorama for the tumorigenic roles of MMP7 across different cancer types. Moreover, MMP7 could be a potential drug therapeutic target in such cancers.

A 3D dynamic finite element model is developed to study the response of the existing tunnels’ concrete structure under the influence of different train speeds and undercrossing with fixed shield excavation. The intersection area of Metro Line 3 in Guangzhou and the intercity railway between Foshan and Dongguan is used as the case study. A programming idea simulating oblique moving-axle loads in the numerical model by using function expressions to constrain activity area is proposed. The Hilber–Hughes–Taylor time-integration scheme is used to calculate the dynamic response parameters of the double-channel rectangular cross section tunnels. Considering fixed excavation steps in the process of shield crossing, acceleration and deformation of the existing tunnels were analyzed under the moving-axle loads of trains at different speeds. From the perspective of the vibration and deformation of existing tunnels, shield excavation and moving speed have their own emphasis on the dynamic influence of the existing tunnel. In addition, the calculation results of the numerical simulation are in good agreement with the data obtained from some field tests, which further verifies the reliability of the calculation method of the numerical model. The results of this research can guide the arrangements for reinforcement measures for existing tunnels in the later stage.

The nonlinear bending of the sandwich plates with graphene nanoplatelets (GPLs) reinforced porous composite (GNRPC) core and two metal skins subjected to different boundary conditions and various loads, such as the concentrated load at the center, linear loads with different slopes passing through the center, linear eccentric loads, uniform loads, and trapezoidal loads, has been presented. The popular four-unknown refined theory accounting for the thickness stretching effects has been employed to model the mechanics of the sandwich plates. The governing equations have been derived from the nonlinear Von Karman strain–displacement relationship and principle of virtual work with subsequent solution by employing the classical finite element method in combination with the Newton downhill method. The convergence of the numerical results has been checked. The accuracy and efficiency of the theory have been confirmed by comparing the obtained results with those available in the literature. Furthermore, a parametric study has been carried out to analyze the effects of load type, boundary conditions, porosity coefficient, GPLs weight fraction, GPLs geometry, and concentrated load radius on the nonlinear central bending deflections of the sandwich plates. In addition, the numerical results reveal that the adopted higher order theory can significantly improve the simulation of the transverse deflection in the thickness direction.