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We demonstrated a method to improve the output performance of a Ti:sapphire laser in the long-wavelength low-gain region with an efficient stimulated Raman scattering process. By shifting the wavelength of the high-gain-band Ti:sapphire laser to the long-wavelength low-gain region, high-performance Stokes operation was achieved in the original long-wavelength low-gain region of the Ti:sapphire laser. With the fundamental wavelength tuning from 870 to 930 nm, first-order Stokes output exceeding 2.5 W was obtained at 930–1000 nm, which was significantly higher than that directly generated by the Ti:sapphire laser, accompanied by better beam quality, shorter pulse duration and narrower linewidth. Under the pump power of 42.1 W, a maximum first-order Stokes power of 3.24 W was obtained at 960 nm, with a conversion efficiency of 7.7%. Furthermore, self-mode-locked modulations of first- and second-order Stokes generation were observed in Ti:sapphire intracavity solid Raman lasers for the first time.
Thanks to its real-time computation efficiency, deep reinforcement learning (DRL) has been widely applied in motion planning for mobile robots. In DRL-based methods, a DRL model computes an action for a robot based on the states of its surrounding obstacles, including other robots that may communicate with it. These methods always assume that the environment is attack-free and the obtained obstacles’ states are reliable. However, in the real world, a robot may suffer from obstacle localization attacks (OLAs), such as sensor attacks, communication attacks, and remote-control attacks, which cause the robot to retrieve inaccurate positions of the surrounding obstacles. In this paper, we propose a robust motion planning method ObsGAN-DRL, integrating a generative adversarial network (GAN) into DRL models to mitigate OLAs in the environment. First, ObsGAN-DRL learns a generator based on the GAN model to compute the approximation of obstacles’ accurate positions in benign and attack scenarios. Therefore, no detectors are required for ObsGAN-DRL. Second, by using the approximation positions of the surrounding obstacles, ObsGAN-DRL can leverage the state-of-the-art DRL methods to compute collision-free motion commands (e.g., velocity) efficiently. Comprehensive experiments show that ObsGAN-DRL can mitigate OLAs effectively and guarantee safety. We also demonstrate the generalization of ObsGAN-DRL.
Persistent cognitive deficits and functional impairments are associated with bipolar disorder (BD), even during the euthymic phase. The dysfunction of default mode network (DMN) is critical for self-referential and emotional mental processes and is implicated in BD. The current study aims to explore the balance of excitatory and inhibitory neurotransmitters, i.e. glutamate and γ-aminobutyric acid (GABA), in hubs of the DMN during the euthymic patients with BD (euBD).
Method
Thirty-four euBD and 55 healthy controls (HC) were recruited to the study. Using proton magnetic resonance spectroscopy (1H-MRS), glutamate (with PRESS sequence) and GABA levels (with MEGAPRESS sequence) were measured in the medial prefrontal cortex/anterior cingulate cortex (mPFC/ACC) and the posterior cingulate gyrus (PCC). Measured concentrations of excitatory glutamate/glutamine (Glx) and inhibitory GABA were used to calculate the excitatory/inhibitory (E/I) ratio. Executive and attentional functions were respectively assessed using the Wisconsin card-sorting test and continuous performance test.
Results
euBD performed worse on attentional function than controls (p = 0.001). Compared to controls, euBD had higher E/I ratios in the PCC (p = 0.023), mainly driven by a higher Glx level in the PCC of euBD (p = 0.002). Only in the BD group, a marginally significant negative association between the mPFC E/I ratio (Glx/GABA) and executive function was observed (p = 0.068).
Conclusions
Disturbed E/I balance, particularly elevated Glx/GABA ratio in PCC is observed in euBD. The E/I balance in hubs of DMN may serve as potential biomarkers for euBD, which may also contribute to their poorer executive function.
In practical applications, many robots equipped with embedded devices have limited computing capabilities. These limitations often hinder the performance of existing dynamic SLAM algorithms, especially when faced with occlusions or processor constraints. Such challenges lead to subpar positioning accuracy and efficiency. This paper introduces a novel lightweight dynamic SLAM algorithm designed primarily to mitigate the interference caused by moving object occlusions. Our proposed approach combines a deep learning object detection algorithm with a Kalman filter. This combination offers prior information about dynamic objects for each SLAM algorithm frame. Leveraging geometric techniques like RANSAC and the epipolar constraint, our method filters out dynamic feature points, focuses on static feature points for pose determination, and enhances the SLAM algorithm’s robustness in dynamic environments. We conducted experimental validations on the TUM public dataset, which demonstrated that our approach elevates positioning accuracy by approximately 54% and boosts the running speed by 75.47% in dynamic scenes.
Natural sepiolite has great potential for application in wound healing, haemostasis and medicines. This paper introduces a versatile solid-state sintering technique for preparing sepiolite-based nanocomposites with enhanced antibacterial properties, and the physical, structural, rheological and antibacterial properties of which were determined to be enhanced. The incorporation of nanosized Ag and metal oxides into sepiolite composites results in a notable improvement in their antibacterial efficacy against Escherichia coli and Staphylococcus aureus in comparison to the unmodified sepiolite. With a low silver content of just 5%, the sepiolite–Ag composite achieves an antibacterial rate of ~100%. Furthermore, the rheological properties exhibited by the sepiolite composites are noteworthy, suggesting their suitability for use in wound-dressing applications due to their exceptional workability. The methodology employed in this research has the potential to offer a viable substitute for the production of economical and effective natural antibacterial nanocomposites.
The thermal stability of surfactant-modified clays plays a key role in the synthesis and processing of organoclay-based nanocomposites. Differential thermal analysis (DTA), thermogravimetric measurement and differential scanning calorimetry (DSC) were used in this study to characterize the thermal stability of hexadecyltrimethylammonium bromide-modified montmorillonites prepared at different surfactant concentrations. Analysis by DSC shows that the molecular environment of the surfactant within the montmorillonite galleries is different from that in the bulk state. The endothermic peak at 70–100°C in the DTA curves of the modified montmorillonites is attributed to both the surfactant phase transformation and the loss of free and interlayer water. With an increase of surfactant-packing density, the amount of water residing in the modified montmorillonite decreases gradually, reflecting the improvement of the hydrophobic property for the organoclay. However, the increase in the surfactant packing density within the galleries leads to a decrease in the thermal stability of the organoclays.
With an increase of initial surfactant concentration for the preparation of organoclays, the surfactant- packing density increases gradually to a ‘saturated’ state. It was found that the cationic surfactant was introduced into the montmorillonite interlayer not only by cation exchange but also by physical adsorption.
A compact high-power ultra-wideband bipolar pulse generator based on a modified Marx circuit is designed, which is mainly composed of a primary power supply, Marx generator, sharpening and cutoff subnanosecond spark gap switches, and coaxial transmission lines. The Marx generator with modified circuit structure has thirty-two stages and is composed of eight disk-like modules. Each module consists of four capacitors, two spark gap switches, four charging inductors, and a mechanical support. To simplify the design of the charging structure and reduce the number of switches, four groups of inductors are used to charge the capacitors of the Marx generator, two of which are used for positive voltage charging and the other two for negative voltage charging. When the capacitor of each stage is charged to 35 kV, the maximum output peak voltage can reach 1 MV when the Marx generator is open circuit. The high-voltage pulse generated by the Marx generator charges the transmission line and forms a bipolar pulse through sharpening and cutoff switches. All transmission lines used for bipolar pulse generation have an impedance of 10 Ω. When the 950 kV pulse voltage generated by the Marx generator is fed into the transmission line, the bipolar pulse peak voltage can reach 390 kV, the center frequency of the pulse is about 400 MHz, and the output peak power is about 15.2 GW.
During the COVID-19 pandemic, there was an increase in online gaming behaviour among college students. This study aimed to examine the impact of online self-help interventions consisting of different components within the Acceptance and Commitment Therapy (ACT) framework on college students’ gaming disorder and gaming frequency. Additionally, it evaluated the effectiveness of both interventions in addressing psychological distress among college students during the COVID-19 pandemic. One intervention was a full ACT program, which consists of six core components, while the other intervention focused on the engaged components of ACT (specifically targeting value-based actions). The study employed a 2 conditions (Full ACT vs. Engaged ACT) × 3 times (pre-, mid- and post-program) design to examine the effectiveness of these interventions. Each intervention consisted of 10 sessions, delivered at a frequency of five sessions per week over a 2-week period for both groups. The participants in this study were enrolled in two online classes. Participants with gaming disorder scores in the top 20% were selected and assigned to either the Full group (N = 49) or the Engaged group (N = 41) for the interventions. The study assessed outcome variables, including gaming disorder, psychological flexibility, daily gaming hours, weekly gaming days and psychological distress, at pre-intervention, mid-intervention, post-intervention and one-month follow-up for both groups. No significant differences were observed between the two groups on these outcomes at the pre-intervention stage. The findings of this study indicate that both interventions effectively reduced gaming disorder and weekly gaming frequency, while enhancing psychological flexibility. Nonetheless, the Engaged group exhibited a significant reduction in daily gaming hours. There was no substantial change in psychological distress in either group during and after the intervention. The implications and limitations of this study were also reported.
The target backsheath field acceleration mechanism is one of the main mechanisms of laser-driven proton acceleration (LDPA) and strongly depends on the comprehensive performance of the ultrashort ultra-intense lasers used as the driving sources. The successful use of the SG-II Peta-watt (SG-II PW) laser facility for LDPA and its applications in radiographic diagnoses have been manifested by the good performance of the SG-II PW facility. Recently, the SG-II PW laser facility has undergone extensive maintenance and a comprehensive technical upgrade in terms of the seed source, laser contrast and terminal focus. LDPA experiments were performed using the maintained SG-II PW laser beam, and the highest cutoff energy of the proton beam was obviously increased. Accordingly, a double-film target structure was used, and the maximum cutoff energy of the proton beam was up to 70 MeV. These results demonstrate that the comprehensive performance of the SG-II PW laser facility was improved significantly.
Given a Polish group G, let $E(G)$ be the right coset equivalence relation $G^{\omega }/c(G)$, where $c(G)$ is the group of all convergent sequences in G. The connected component of the identity of a Polish group G is denoted by $G_0$.
Let $G,H$ be locally compact abelian Polish groups. If $E(G)\leq _B E(H)$, then there is a continuous homomorphism $S:G_0\rightarrow H_0$ such that $\ker (S)$ is non-archimedean. The converse is also true when G is connected and compact.
For $n\in {\mathbb {N}}^+$, the partially ordered set $P(\omega )/\mbox {Fin}$ can be embedded into Borel equivalence relations between $E({\mathbb {R}}^n)$ and $E({\mathbb {T}}^n)$.
In the Three Gorges and adjacent areas, there are three planation surfaces and five terraces along the Yangtze River that record the evolution history of the river system. Here, we used diagnostic heavy minerals, U-Pb geochronology, and trace elements of detrital zircons from one planation surface, two terraces, and a modern point bar to reconstruct the evolution history of the upper Yangtze River, specifically the Chuan River in the Sichuan Basin. The sediments in the lowest planation surface had different felsic source rocks derived from east of the Three Gorges, which indicated that before the disintegration of the lowest planation surface (0.75 Ma), there were two paleorivers: the westward-flowing paleo-Chuan River and eastward-flowing paleo-Yangtze River separated by the Huangling Dome. At 0.75–0.73 Ma, the dominant detrital zircons from the Sichuan Basin in the sediments of terrace T5 (the highest terrace) confirmed that the paleo-Yangtze River cut through the Three Gorges and captured the paleo-Chuan River, and the Daliang Mountains became the new drainage divide. Finally, the appearance of materials from the upper Jinsha River in terrace T2 indicated that the paleo-Yangtze River progressively captured the paleo-Jinsha River, and the modern upper Yangtze River formed before 0.05 Ma. These river capture events of the upper Yangtze River confirmed the Quaternary uplift of the SE Tibetan Plateau.
The objective of this paper is to present the movement mechanisms of transport aircraft response to severe clear-air turbulence to obtain the loss of control prevention for pilot training in IATA – Loss of Control In-flight (LOC-I) program. The transport aircraft in transonic flight is subjected to severe clear-air turbulence, resulting in a sudden plunging motion with the abrupt change in flight attitude and gravitational acceleration. The comparative analyses of the flight environment and aircraft response to severe clear-air turbulence for two four-jet aircraft are studied. The one with a larger dropped-off altitude during the plunging motion will be chosen to construct the movement mechanism. The nonlinear unsteady aerodynamic model of the chosen transport is established through flight data mining and the fuzzy-logic modeling of artificial intelligence technique based on post-flight data. The crosswind before the turbulence encounter will easily induce a rolling motion and then the sudden plunging motion during the turbulence encounter. The influences of the varying vertical wind and crosswind on loss of control are presented. To formulate preventive actions, the situation awareness of varying crosswind encountering for the operational pilot will be studied further in the future. The present study is initiated to examine the possible mitigation concepts of accident prevention for the pilot training course of IATA – Loss of Control In-flight (LOC-I) program.
Using data from three automatic weather stations (LGB69, Eagle and Dome A) from distinctly different climatological zones along the CHINARE (Chinese National Antarctic Research Expedition) traverse route from Zhongshan Station to Dome A, we investigated the characteristics of meteorological conditions and subsurface heat conduction. Spatial analysis indicated decreasing trends in air temperature, relative humidity and wind speed from the coastal katabatic wind zone to the inland plateau region, and air temperatures clearly showed a strong daily variability in winter, suggesting the effect from the fluctuation in the Antarctic atmospheric system. We also analyzed the optimal response time of the 1 and 3 m depth snow temperatures to the 0.1 m depth snow temperature for each site under clear/overcast and day/night situations. This showed an important enhancement to the heat transfer from shortwave radiation penetration. Using an iterative optimization method, we estimated the subsurface heat conduction variations along the transect. This was ~3–5 W m–2. Multiple maxima in daily mean subsurface fluxes were found in winter, with a typical value above 2 W m–2, while a single minimum value under –2 W m–2 was found in summer. On an annual scale, a larger mean loss of subsurface heat conduction was observed in the inland plateau compared to in the coastal katabatic area. Finally, we discussed the possible influences of turbulent and radiant transport on the vertical heat response and confirmed the wind enhancement on the growth of thermal conductivity. This preliminary study provides a brief perspective and an important reference for studying subsurface heat conduction in inland areas of Antarctica.
Collision avoidance is critical in multirobot systems. Most of the current methods for collision avoidance either require high computation costs (e.g., velocity obstacles and mathematical optimization) or cannot always provide safety guarantees (e.g., learning-based methods). Moreover, they cannot deal with uncertain sensing data and linguistic requirements (e.g., the speed of a robot should not be large when it is near to other robots). Hence, to guarantee real-time collision avoidance and deal with linguistic requirements, a distributed and hybrid motion planning method, named Fuzzy-VO, is proposed for multirobot systems. It contains two basic components: fuzzy rules, which can deal with linguistic requirements and compute motion efficiently, and velocity obstacles (VOs), which can generate collision-free motion effectively. The Fuzzy-VO applies an intruder selection method to mitigate the exponential increase of the number of fuzzy rules. In detail, at any time instant, a robot checks the robots that it may collide with and retrieves the most dangerous robot in each sector based on the predicted collision time; then, the robot generates its velocity in real-time via fuzzy inference and VO-based fine-tuning. At each time instant, a robot only needs to retrieve its neighbors’ current positions and velocities, so the method is fully distributed. Extensive simulations with a different number of robots are carried out to compare the performance of Fuzzy-VO with the conventional fuzzy rule method and the VO-based method from different aspects. The results show that: Compared with the conventional fuzzy rule method, the average success rate of the proposed method can be increased by 306.5%; compared with the VO-based method, the average one-step decision time is reduced by 740.9%.
This study aimed to analyze the clinical effects of microdissection testicular sperm extraction (micro-TESE) surgery combined with an intracytoplasmic sperm injection (ICSI) regimen in the treatment of non-obstructive azoospermia (NOA) patients with different etiologies. In total, 128 NOA patients participated in this study, in which they received infertility treatment by micro-TESE surgery combined with an ICSI regimen, and all patients were divided into three groups [the Klinefelter syndrome (KS), the idiopathic and the secondary NOA groups]. In addition, the sperm retrieval rate (SRR), fertilization rate, embryo development status and clinical treatment effects were analyzed. Among the 128 NOA patients, the SRR of KS NOA patients was 48.65%, those of idiopathic and the secondary patients were 33.82% and 73.91%, respectively. Regardless of etiologies, there was no correlation with age, hormone value or testicular volume. Further analysis showed that the SRR of the KS group was positively related with testosterone (T) values, and the SRR of the secondary group had a positive relationship with follicle-stimulating hormone or luteinizing hormone values. In the subsequent clinical treatment, the retrieved sperm was subjected to ICSI and achieved good treatment effects, especially in the secondary group, and the implantation rate (55.56%) and clinical pregnancy rate (68.42%) were both higher than those of the idiopathic group (28.75% and 40.00%) and KS group (22.05% and 30.77%). Micro-TESE surgery combined with ICSI insemination is the most effective treatment regimen for NOA patients. The SRR of NOA patients with different etiologies are related to certain specific factors, and micro-TESE surgery seems to be the ideal and only way to have biological children.
Telocyte (TC)—a new type of interstitial cell with long telopodes, can form cellular junctions with various tissues or cells to participate in the regulation of multitudes of physiological activities and diseases. This study aimed to characterize the morphology, molecular features, and potential functions of hormone regulation in Chinese soft-shelled turtle (Pelodiscus sinensis) testis TCs at different reproductive stages by histological evaluation, immunohistochemistry (IHC), immunofluorescence (IF), and transmission electron microscopy. During hibernation, TCs were widely distributed in the interstitial tissue. In contrast, during reproductive activity, TCs were noted to be in close proximity with peritubular myoid cells surrounding the seminiferous tubule. Moreover, formed cell–cell junctions were observed between TCs and PTMs. The results of IHC and IF showed that the immunophenotype of testicular TCs in hibernating Chinese soft-shelled turtles is CD34+Vimentin−, while the reproductive telopodes (Tps) show low expression of vimentin. The androgen receptor is expressed in Tps of TCs of testis during hibernation. Our results showed also that TCs in seasonal breeding animals regulate the activity of neighboring cells by releasing extracellular microvesicles (EXMVs), thus influencing the activity of spermatogenesis and steroidogenesis. Consideration of our novel and interesting results indicate that the whole area warrants further research.
Neuroimaging studies in Wilson’s disease (WD) have identified various alterations in white matter (WM) microstructural organization. However, it remains unclear whether these alterations are localized to specific regions of fiber tracts, and what diagnostic value they might have. The purpose of this study is to explore the spatial profile of WM abnormalities along defined fiber tracts in WD and its clinical relevance.
Methods:
Ninety-nine patients with WD (62 men and 37 women) and 91 age- and sex-matched controls (59 men and 32 women) were recruited to take part in experiments of diffusion-weighted imaging with 64 gradient vectors. The data were calculated by FMRIB Software Library (FSL) software and Automated Fiber Quantification (AFQ) software. After registration, patient groups and normal groups were compared by Mann–Whitney U test analysis.
Results:
Compared with the controls, the patients with WD showed widespread fractional anisotropy reduction and mean diffusivity, radial diffusivity elevation of identified fiber tracts. Significant correlations between diffusion tensor imaging (DTI) parameters and the neurological Unified Wilson’s Disease Rating Scale (UWDRS-N), serum ceruloplasmin, and 24-h urinary copper excretion were found.
Conclusions:
The present study has provided evidence that the metrics of DTI could be utilized as a potential biomarker of neuropathological symptoms in WD. Damage to the microstructure of callosum forceps and corticospinal tract may be involved in the pathophysiological process of neurological symptoms in WD patients, such as gait and balance disturbances, involuntary movements, dysphagia, and autonomic dysfunction.
The great demographic pressure brings tremendous volume of beef demand. The key to solve this problem is the growth and development of Chinese cattle. In order to find molecular markers conducive to the growth and development of Chinese cattle, sequencing was used to determine the position of copy number variations (CNVs), bioinformatics analysis was used to predict the function of ZNF146 gene, real-time fluorescent quantitative polymerase chain reaction (qPCR) was used for CNV genotyping and one-way analysis of variance was used for association analysis. The results showed that there exists CNV in Chr 18: 47225201-47229600 (5.0.1 version) of ZNF146 gene through the early sequencing results in the laboratory and predicted ZNF146 gene was expressed in liver, skeletal muscle and breast cells, and was amplified or overexpressed in pancreatic cancer, which promoted the development of tumour through bioinformatics. Therefore, it is predicted that ZNF146 gene affects the proliferation of muscle cells, and then affects the growth and development of cattle. Furthermore, CNV genotyping of ZNF146 gene was three types (deletion type, normal type and duplication type) by Real-time fluorescent quantitative PCR (qPCR). The association analysis results showed that ZNF146-CNV was significantly correlated with rump length of Qinchuan cattle, hucklebone width of Jiaxian red cattle and heart girth of Yunling cattle. From the above results, ZNF146-CNV had a significant effect on growth traits, which provided an important candidate molecular marker for growth and development of Chinese cattle.