A cross-sectional mental-health survey of Chinese postgraduate students majoring in stomatology post COVID-19 restrictions.

Background: The psychological status of Chinese postgraduate students majoring in stomatology after the COVID-19 restrictions still remains unclear. The objective of this study is to evaluate the mental status through a cross-sectional survey and gather related theoretical evidence for psychological intervention on postgraduate students majoring in stomatology. Methods: An online survey was administered, and subjective well-being, anxiety, stress and depression symptoms were assessed using the 5-item World Health Organization Well-Being Index (WHO-5), item Generalized Anxiety Disorder Scale (GAD-7), 10-item Perceived Stress Scale (PSS-10), and Patient Health Questionnaire-9 (PHQ-9), respectively, wherein suicidal ideation and sleep-related problems were measured with PHQ-9 and Insomnia Severity Index (ISI). Results: A total of 208 participants who completed one questionnaire were considered as valid. It was found that female respondents generally exhibited significantly higher levels of PSS-10, PHQ-9, and GAD-7 scores and shorter physical activity hours than male students. Students from rural areas demonstrated significantly higher levels of PHQ-9, suicidal ideation, and less portion of good or fair family economic support. Additionally, individuals from only-child families reported increased levels of activity hours (1.78 ± 2.07, p = 0.045) and a higher portion (55.10%, p = 0.007) of having clear future plan as compared with multiple-child families. The risk factors for anxiety symptoms (GAD-7 score) were higher scores of PSS-10 (OR = 1.15, 95% CI = 1.09-1.22), PHQ-9 (OR = 1.35, 95% CI = 1.22-1.49), and ISI-7 (OR = 1.14, 95% CI = 1.06-1.23), while owning a clear graduation plan was the protective factor (OR = 0.55, 95% CI = 0.31-0.98). Moreover, the risk factors for depressive symptoms (PHQ-9) included PSS-10 (OR = 1.10, 95% CI = 1.04-1.16), GAD-7 (OR = 1.38, 95% CI = 1.25-1.52), suicidal ideation (OR = 5.66, 95% CI = 3.37-9.51), and ISI-7 (OR = 1.17, 95% CI = 1.09-1.25). Approximately 98.08% of Chinese postgraduates studying stomatology reported experiencing at least moderate stress after the COVID-19 restrictions. Conclusion: Within the limitations of this study, senior students were more inclined to stress, while anxiety symptoms were related to severer levels of stress, depression, and insomnia. Depressive symptoms were associated with higher levels of stress, anxiety, insomnia, suicidal ideation, and lower levels of self-reported well-being. Thus, psychological interventions for postgraduates should be timely and appropriately implemented by strengthening well-being, reasonably planning for the future, and good physique, thereby mitigating the psychological issues after COVID-19 restrictions.

Competition for gradient-free tuning of large language models: approaches, results, current challenges and future directions.

This perspective presents a brief overview of the background of Gradient-free tuning for large language models competition, the championship scheme, as well as the challenges and future directions.

Fabrication of direct Z-scheme Cu2O@V-CN (octa) heterojunction with exposed (111) lattice planes and nitrogen-rich vacancies for rapid sterilization.

The Z-scheme heterojunction has demonstrated significant potential for promoting photogenerated carrier separation. However, the rational design of all-solid Z-scheme heterojunctions catalysts and the controversies about carrier transfer path of direct Z-scheme heterojunctions catalysts face various challenges. Herein, a novel heterojunction, Cu2O@V-CN (octa), was fabricated using V-CN (carbon nitride with nitrogen-rich vacancies) in-situ electrostatic self-wrapping Cu2O octahedra. Density functional theory (DFT) calculations revealed that the separation of carriers across the Cu2O@V-CN (octa) heterointerface was directly mapped to the Z-scheme mechanism compared to Cu2O/V-CN (sphere). This is because the Cu2O octahedra expose more highly active (111) lattice planes with more terminal Cu atoms and V-CN with abundant nitrogen vacancies to form delocalized electronic structures like electronic reservoirs. This facilitates the wrapping of Cu2O octahedra by V-CN and protects their stability via tighter interfacial contact, thus enhancing the tunneling of carriers for rapid photocatalytic sterilization. These findings provide novel approaches for designing high-efficiency Cu2O-based photocatalytic antifoulants for practical applications.

Full solar spectrum-driven Cu2O/PDINH heterostructure with enhanced photocatalytic antibacterial activity and mechanism insight.

Marine biofouling hazards the sustainable development of the environment and has become a potential threat to environmental and ecological security. Photocatalytic antibacterial agents driven by the full solar spectrum are promising antifouling agents for environmental protection. The cuprous oxide/perylene-3,4,9,10-tetracarboximide (Cu2O/PDINH) heterostructure was successfully constructed by integrating p-type Cu2O and n-type PDINH to improve photocatalytic antibacterial efficiency. PDINH extended the absorption spectrum from ultraviolet to near-infrared, improving light utilization by 75 %. The Cu2O/PDINH heterostructure reduced the toxicity risk of Cu2O for environmental pollution, achieved full solar spectrum drive and overcame the inherent defect that Cu2O cannot produce singlet oxygen. The Cu2O/PDINH heterostructure exhibited excellent long-term and photocatalytic antibacterial activity with an antibacterial rate of > 90 % due to the sterilization of copper ions and the continuous generation of ROS driven by the full solar spectrum. This inorganic-organic Cu2O/PDINH heterostructure shows great application prospects in energy and the environment. The Cu2O/PDINH heterostructure with effective ROS increase and superior photocatalytic sterilization efficiency has great potential for environmentally friendly marine antifouling agents.

High-efficiency, high-repetition-rate cavity-dumped Q-switched Yb:YAG thin-disk laser based on a 72-pass pump module.

We demonstrated a compact cavity-dumped Q-switched Yb:YAG laser based on a 72-pass pump module. A highly stable nanosecond pulse laser with a duration of 18.38 ns was achieved at a repetition rate of 100 kHz, which is pumped by multimode laser diode stacks at 969 nm. The average output power of more than 150 W is delivered in a good output beam characterized by M2 = 1.53. The result shows that the pulse duration derived from simulation agrees well with the one retrieved from the experimental measurements. To the best of our knowledge, the 43.5% optical-optical efficiency is the highest reported to date from a cavity-dumped Q-switched Yb:YAG TDL (thin-disk laser).

Resonators with a continuously variable output coupling rate to enhance output performance of Yb:YAG thin-disk lasers.

Beam quality and average output power are two long-sought parameters of continuous-wave lasers. The operating characteristics of a Yb:YAG thin-disk laser based on a 72-pass pump module using output couplers with continuously variable coupling rates are reported. When the pump power is 450 W, the average power of more than 210 W is obtained, and the corresponding optical-optical efficiency is about 46.67%. The output beam is near diffraction limited with M2=1.20 and 1.18 on the horizontal and vertical directions respectively. The thin-disk laser maintains the beam quality near diffraction limited within the whole pump power range by continuously changing the coupling rate of the output coupler (the combination of thin film polarizer and quarter-wave plate) according to the incident pump power. The experimental results show that by continuously changing the coupling rate, combined with the dynamic change of thermal lens effect, the laser beam quality factor M2 can be reduced from 2.0 to 1.2, and the beam quality can be improved by about 40%. The improvement of and increase of average output power confirm that resonators with continuously variable coupling rate are a promising method for enhancing output performance of thin-disk lasers.