To address the issues of low positioning accuracy and weak robustness of prior visual simultaneous localization and mapping (VSLAM) systems in dynamic environments, a semantic VSLAM (Sem-VSLAM) approach based on deep learning is proposed in this article. The proposed Sem-VSLAM algorithm adds semantic segmentation threads in parallel based on the open-source ORB-SLAM2’s visual odometry. First, while extracting the ORB features from an RGB-D image, the frame image is semantically segmented, and the segmented results are detected and repaired. Then, the feature points of dynamic objects are eliminated by using semantic information and motion consistency detection, and the poses are estimated by using the remaining feature points after the dynamic feature elimination. Finally, a 3D point cloud map is constructed by using tracking information and semantic information. The experiment uses Technical University of Munich public data to show the usefulness of the Sem-VSLAM algorithm. The experimental results show that the Sem-VSLAM algorithm can reduce the absolute trajectory error and relative attitude error of attitude estimation by about 95% compared to the ORB-SLAM2 algorithm and by about 14% compared to the VO-YOLOv5s in a highly dynamic environment and the average time consumption of tracking each frame image reaches 61 ms. It is verified that the Sem-VSLAM algorithm effectively improves the robustness and positioning accuracy in high dynamic environment and owning a satisfying real-time performance. Therefore, the Sem-VSLAM has a better mapping effect in a highly dynamic environment.

The development of active and low-cost transition metal oxide-based catalysts was vital for the catalytic oxidation of toluene. This study aimed to prepare Fe-Mn oxide catalysts by Mn-rich limonite, and investigate the catalytic activity and mechanism for toluene oxidation. The natural Mn-rich limonite was thermally activated at different temperatures and these thermally activated samples exhibited different oxidation activities. YL-300, obtained through thermal treatment at 300°C, exhibited excellent catalytic activity, showing 90% toluene conversion at 239°C (1000 ppm toluene) and remarkable catalytic stability even in the presence of water vapor (5 vol.%). The amount of oxygen vacancies in the catalyst was regulated by tuning the thermal treatment temperatures. Optimal thermal treatment facilitated the increase of oxygen vacancies and enhanced the oxygen mobility and redox capacity of YL-300, contributing to the complete oxidation of toluene to H2O and CO2. The oxidation of toluene was greatly influenced by the adsorbed oxygen species. This study demonstrates the potential of Mn-rich limonite as a promising catalyst for toluene oxidation, thereby promoting the utilization of natural mineral materials in the field of environmental pollution control.

Hyper-redundant cable-driven manipulators (CDMs) are widely used for operations in confined spaces due to their slender bodies and multiple degrees of freedom. Most research focuses on their path following but not path planning. This work investigates a deep deterministic policy gradient (DDPG)-based path-planning algorithm for CDMs in multi-obstacle environments. To plan passable paths under many constraints, a DDPG algorithm is modified according to features of CDMs. To improve adaptability of planned paths, a specialized reward function is newly designed. In this function, such factors as smoothness, arrival time and distance are taken into account. Results of simulations and physical experiments are presented to demonstrate the performances of the proposed methods for planning paths of CDMs.

Hyper-redundant manipulators (HRMs) exhibit promising adaptability and superior dexterity in cavity detection tasks, owing to their snake-like segmented backbones. Due to the safety concern in contactless operating tasks, reliable motion planning in a confined environment for HRMs is very challenging. However, existing expanding-based obstacle avoidance methods are not feasible in narrow environments, as they will excessively occupy free spaces required for maneuvering. In this work, a local collision-free motion planning strategy based on dynamic safety envelope (DSE) is proposed for HRMs. First, the local motion of HRMs is analyzed in detail, and DSE is proposed for the first time to describe the boundary of the collision-free area. Then, to maximize the efficient utilization of narrow spaces, a reference trajectory for HRM is roughly planned without expanding obstacles. Further, a tip-guided trajectory tracking method based on configuration prediction is proposed by considering the discrete characteristics of rigid links to avoid obstacles. During the tracking process, DSEs are applied to evaluate collision risk and optimize the configuration. Finally, to validate the effectiveness of our proposed method, simulations are conducted, followed by experiments by using a 18-degrees of freedom mobile HRM prototype system.

In the double-cone ignition scheme of inertial confinement fusion, the head-on collision of two compressed fuel jets from the cone-tips forms an isochoric plasma, which is then heated suddenly by a MeV relativistic electron beam produced by ultra-intense picosecond laser pulses. This fast-heating process was studied experimentally at the Shenguang II upgrade laser facility. By observing temporal-resolved X-ray emission and the spatial-resolved X-ray spectrum, the colliding process and heating process are carefully studied. The colliding plasma was imaged to have dimensions of approximately 86 μm in the implosion direction and approximately 120 μm in the heating direction. By comparing the simulated plasma X-ray spectrum with experimental data, the electron temperature of the heated plasma was found to rapidly increase to 600 ± 50 eV, almost doubling the temperature achieved before the heating laser incidence.

Seed germination is a pivotal period of plant growth and development. This process can be divided into four major stages, swelling absorption, seed coat dehiscence, radicle emergence and radicle elongation. Cupressus gigantea, a tree native to Tibet, China, is characterized by its resistance to stresses such as cold, and drought, and has a high economic and ecological value. Nevertheless, given its unique geographic location, its seeds are difficult to germinate. Therefore, it is crucial to explore the mechanisms involved in seed germination in this species to improve the germination efficiency of its seeds, thereby protecting this high-quality resource. Here, our findings indicate that seed germination was enhanced when exposed to a 6-h/8-h light/dark photoperiod, coupled with a temperature of 20°C. Furthermore, the application of exogenous GA3 (1 mg/ml, about 2.9 mM) stimulated the germination of C. gigantea seeds. Subsequently, proteomics was used to detect changes in protein expression during the four stages of seed germination. We identified 34 differentially expressed proteins (DEPs), including 13 at the radicle pre-emergence stage, and 17 at the radicle elongation stage. These DEPs were classified into eight functional groups, cytoskeletal proteins, energy metabolism, membrane transport, stress response, molecular chaperones, amino acid metabolism, antioxidant system and ABA signalling pathway. Most of them were found to be closely associated with amino acid metabolism. Combined, these findings indicate that, along with temperature and light, exogenous GA3 can increase the germination efficiency of C. gigantea seeds. Our study also offers insights into the changes in protein expression patterns in C. gigantea seeds during germination.

This paper retrospectively analysed the prevalence of macrolide-resistant Mycoplasma pneumoniae (MRMP) in some parts of China. Between January 2013 and December 2019, we collected 4,145 respiratory samples, including pharyngeal swabs and alveolar lavage fluid. The highest PCR-positive rate of M. pneumoniae was 74.5% in Beijing, the highest resistance rate was 100% in Shanghai, and Gansu was the lowest with 20%. The highest PCR-positive rate of M. pneumoniae was 74.5% in 2013, and the highest MRMP was 97.4% in 2019; the PCR-positive rate of M. pneumoniae for adults in Beijing was 17.9% and the MRMP was 10.48%. Among the children diagnosed with community-acquired pneumonia (CAP), the PCR-positive and macrolide-resistant rates of M. pneumoniae were both higher in the severe ones. A2063G in domain V of 23S rRNA was the major macrolide-resistant mutation, accounting for more than 90%. The MIC values of all MRMP to erythromycin and azithromycin were ≥ 64 μg/ml, and the MICs of tetracycline and levofloxacin were ≤ 0.5 μg/ml and ≤ 1 μg/ml, respectively. The macrolide resistance varied in different regions and years. Among inpatients, the macrolide-resistant rate was higher in severe pneumonia. A2063G was the common mutation, and we found no resistance to tetracycline and levofloxacin.

Mythimna separata (Lepidoptera: Noctuidae) is an omnivorous pest that poses a great threat to food security. Insect antimicrobial peptides (AMPs) are small peptides that are important effector molecules of innate immunity. Here, we investigated the role of the AMP cecropin B in the growth, development, and immunity of M. separata. The gene encoding M. separata cecropin B (MscecropinB) was cloned. The expression of MscecropinB was determined in different developmental stages and tissues of M. separata. It was highest in the prepupal stage, followed by the pupal stage. Among larval stages, the highest expression was observed in the fourth instar. Tissue expression analysis of fourth instar larvae showed that MscecropinB was highly expressed in the fat body and haemolymph. An increase in population density led to upregulation of MscecropinB expression. MscecropinB expression was also upregulated by the infection of third and fourth instar M. separata with Beauveria bassiana or Bacillus thuringiensis (Bt). RNA interference (RNAi) targeting MscecropinB inhibited the emergence rate and fecundity of M. separata, and resulted in an increased sensitivity to B. bassiana and Bt. The mortality of M. separata larvae was significantly higher in pathogen plus RNAi-treated M. separata than in controls treated with pathogens only. Our findings indicate that MscecropinB functions in the eclosion and fecundity of M. separata and plays an important role in resistance to infection by B. bassiana and Bt.

Snake robots can move flexibly due to their special bodies and gaits. However, it is difficult to plan their motion in multi-obstacle environments due to their complex models. To solve this problem, this work investigates a reinforcement learning-based motion planning method. To plan feasible paths, together with a modified deep Q-learning algorithm, a Floyd-moving average algorithm is proposed to ensure smoothness and adaptability of paths for snake robots’ passing. An improved path integral algorithm is used to work out gait parameters to control snake robots to move along the planned paths. To speed up the training of parameters, a strategy combining serial training, parallel training, and experience replaying modules is designed. Moreover, we have designed a motion planning framework consists of path planning, path smoothing, and motion planning. Various simulations are conducted to validate the effectiveness of the proposed algorithms.

This study gives insights into the interfacial instabilities of a ventilation cavity by injecting gas vertically into the horizontal liquid crossflow through both numerical and experimental investigations. We identified four distinct regimes of the ventilation cavity based on their topological characteristics: (I) discrete bubble, (II) continuous cavity, (III) bifurcated cavity, and (IV) bubble plume. The boundaries for these regimes are delineated within the parameter space of crossflow velocity and jet speed. A comprehensive analysis of the flow characteristics associated with each regime is presented, encompassing the phase mixing properties, the dominant frequency of pulsation, and the time-averaged profile of the cavity. This study conducted a detailed investigation of the periodic pulsation at the leading-edge interface of the cavity, also known as the ‘puffing phenomenon’. The results of local spectral analysis and dynamic mode decomposition indicate that the high-frequency instability in the near-field region exhibits the most significant growth rate. In contrast, the low-frequency mode with the largest amplitude spans a broader region from the orifice to the cavity branches. A conceptual model has been proposed to elucidate the mechanism behind the pulsation phenomenon observed along the cavity interface: the pulsation results from the alternate intrusion of the crossflow and the cavity recovery at the leading edge, being governed mainly by the periodic oscillating imbalance between the static pressure of gas near the orifice and the stagnation pressure of crossflow at the leading edge.

To investigate the effects of co-infection with Clonorchis sinensis (C. sinensis) on T cell exhaustion levels in patients with chronic hepatitis B, we enrolled clinical cases in this study, including the patients with concomitant C. sinensis and HBV infection. In this study, we detected inhibitory receptors and cytokine expression in circulating CD4+ and CD8+ T cells by flow cytometry. PD-1 and TIM-3 expression levels were significantly higher on CD4+ T and CD8+ T cells from co-infected patients than on those from the HBV patients. In addition, CD4+ T cells and CD8+ T cells function were significantly inhibited by C. sinensis and HBV co-infection compared with HBV single infection, secreting lower levels of Interferon gamma (IFN-γ), Interleukin-2 (IL-2), and TNF-α. Our current results suggested that C. sinensis co-infection could exacerbate T cell exhaustion in patients with chronic hepatitis B. PD-1 and TIM-3 could be novel biomarkers for T cell exhaustion in patients with Clonorchis sinensis and chronic hepatitis B co-infection. Furthermore, it may be one possible reason for the weaker response to antiviral therapies and the chronicity of HBV infection in co-infected patients. We must realize the importance of C. sinensis treatment for HBV-infected patients. It might provide useful information for clinical doctors to choose the right treatment plans.

Various magmatisms during the subduction-collision process are crucial to reveal the long-term tectonic evolution of the eastern Central Asian Orogenic Belt. In this paper, we present major and trace elements of whole-rock, zircon U-Pb dating and Hf isotope of the Shanmen pluton. Results imply that the Shanmen pluton consists of quartz diorite and mylonitic granite, with zircon U-Pb ages of 263.7–259.6 Ma. The studied quartz diorite contains high Sr/Y (51.19–90.87) and (La/Yb)N (7.82–13.62) ratios, and belongs to adakitic rocks. Coupled with the positive εHf(t) values of +5.71 to +12.8 with no obvious Eu anomaly, we propose that quartz diorite is the product of the interaction between different degrees of slab melt and the overlying mantle wedge. In contrast, the mylonitic granite has lower MgO (0.28 wt% – 0.47 wt%) contents and positive εHf(t) values of +7.79 to +10.15, indicating an affinity with I-type granite originated by partial melting of the intermediate-basic lower crust. The geochemical characteristics and lithological assemblages, along with the Permian magmatic rocks in the Changchun-Kaiyuan area displaying arc rocks affinity, propose their formation is related to the southward subduction of the Paleo-Asian Ocean (PAO). Based on this study and previous evidence, we lean towards adopting a middle-late Permian slab break-off model, wherein the PAO did not close until the late Permian.

Lipase is an industrial enzyme, the catalytic efficiency of which is restricted by various environmental factors. To improve this efficiency, immobilization technology has been utilized in the past to improve the stability of lipase in harsh conditions. Immobilization technology can be divided into physical methods and chemical methods. Some unsolved problems remain in current immobilization technology. The interaction between enzyme and immobilization support is weak and reversible during physical adsorption, resulting in poor stability of the immobilized enzyme and the contamination of substrate solution by leached enzymes. In chemical methods, enzyme-active sites might be inactivated due to the chemical reactions between enzyme molecules and support, resulting in a decrease in the enzymes’ catalytic activity (Liu et al., 2018a). The objective of the current study was to construct a nanostructured lipase via Mg-amino-clay as a carrier and improve the catalytic activity and stability of lipase by immobilization. Lipase produced by Aspergillus oryzae was immobilized on aminopropyl functionalized magnesium phyllosilicate (a 2:1 trioctahedral talc-like silicate Mg-amino-clay) via a 1-(3-Dimethylaminopropyl)-3-ethyl-carbodiimide hydrochloride (EDC) coupling agent. The physical and chemical properties of the Mg-amino-clay and Mg-amino-clay-based nanostructured biocatalyst (Mg-clay-lipase) were characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, and scanning electron microscopy. Optimal immobilization conditions were determined by taking into account the following variables: amount of initial lipase, EDC concentration, and reaction time. The results revealed that the optimum temperature, pH, and thermal stability of Mg-clay-lipase were greater than equivalent values for free lipase under optimal conditions (described below – Process for Immobilization of Lipase on Mg-amino-clay). The Michaelis-Menten constant (Km) values were 5.25 mM and 7.42 mM while the maximum reaction rates (vmax) were 30.58 mM/(L·min) and 55.87 mM/(L·min) for free lipase and Mg-clay-lipase, respectively. The present study provided a new nanostructured biocatalyst and demonstrated that the enzyme activity and stability of Mg-clay-lipase were superior to those of free lipase due to the mechanism of 'interface activation'.

Recurrent pregnancy loss (RPL) is both mental and physical health problem affecting about 1–5% of women of childbearing age. The etiology of RPL is complex, involving chromosomal abnormalities, autoimmune diseases, metabolic disorders, and endometrial dysfunction. The causes of abortion are still unknown in more than 50% of these cases. With the development of science and technology, an increasing number of scholars focus on this field and find that genetic factors may play an essential role in unexplained RPL, such as embolism-related genes, immune factor-related genes, and chromosomal numeric, and structural variation. This review summarizes the genetic factors associated with RPL, including genetic mutations and genetic polymorphisms, chromosomal variants, and chromosomal polymorphisms. Many related genetic factors have been found to be demographically and geographically relevant, some of which can be used for risk prediction or screening for the etiology of RPL. However, it is difficult to predict and prevent RPL due to uncertain pathogenesis and highly variable clinical presentation. Therefore, the genetic factors of RPL still need plentiful research to obtain a more accurate understanding of its pathogenesis and to provide more detection means for the screening and prevention of RPL.

A low-energy proton accelerator named pulsed synchronous linear accelerator (PSLA) is proposed and developed at the Institute of Fluid Physics, which is driven by unipolar-pulsed high voltages. Pulsed-accelerating electric fields and low-energy ion beams are precisely synchronized on temporal and spatial positions for continuous acceleration. The operating mode and the features of the PSLA are introduced. At present, the feasibility of a low-energy proton PSLA has been verified in principle. An average accelerating gradient up to 3 MV/m for protons is achieved.

In order to establish a compact all-optical Thomson scattering source, experimental studies were conducted on the 45 TW Ti: sapphire laser facility. By including a steel wafer, mixed gas, and plasma mirror into a double-exit jet, several mechanisms, such as shock-assisted ionization injection, ionization injection, and driving laser reflection, were integrated into one source. So, the source of complexity was remarkably reduced. Electron bunches with central energy fluctuating from 90 to 160 MeV can be produced. Plasma mirrors were used to reflect the driving laser. The scattering of the reflected laser on the electron bunches led to the generation of X-ray photons. Through comparing the X-ray spots under different experimental conditions, it is confirmed that the X-ray photons are generated by Thomson scattering. For further application, the energy spectra and source size of the Thomson scattering source were measured. The unfolded spectrum contains a large amount of low-energy photons besides a peak near 67 keV. Through importing the electron energy spectrum into the Monte Carlo simulation code, the different contributions of the photons with small and large emitting angles can be used to explain the origin of the unfolded spectrum. The maximum photon energy extended to about 500 keV. The total photon production was 107/pulse. The FWHM source size was about 12 μm.