Non-suicidal self-injury and professional psychological help-seeking among Chinese left-behind children: prevalence and influencing factors.

BACKGROUND: Non-suicidal self-injury (NSSI) is a risk factor for suicide. This study aimed to investigate the prevalence of NSSI and professional psychological help-seeking status and influencing factors among left-behind children (LBC) in China. METHODS: We implemented a population-based cross-sectional study in participants aged 10-18 years. Sociodemographic characteristics, NSSI, help-seeking status and coping style were measured by self-reported questionnaires. A total of 16,866 valid questionnaires were collected, including 6096 LBC. Binary logistic regression models were used to analyze the factors influencing NSSI and professional psychological help-seeking. RESULTS: The incidence of NSSI among LBC was 4.6%, significantly higher than that of non-left-behind children (NLBC). This incidence was higher among girls. Moreover, 53.9% of LBC with NSSI did not receive any treatment and only 22.0% sought professional psychological help. LBC often adopt emotion-oriented coping styles, specifically, those with NSSI. LBC with NSSI who seek professional help tend to adopt problem-oriented coping styles. Logistic regression analysis revealed that girls, learning stage, single-parent, remarried families, patience, and emotional venting were risk factors for NSSI in LBC, while problem-solving and social support seeking were protective factors. Moreover, problem-solving was also a predictor for seeking professional psychological help, patience will prevent it. LIMITATIONS: This was an online survey. CONCLUSIONS: The prevalence of NSSI in LBC is high. Gender, grade, family structure, and coping style affect the occurrence of NSSI among LBC. Only a few LBC with NSSI seek professional psychological help, while the coping style will affect the help-seeking behavior.

Physicochemical and Photocatalytic Properties of 3D-Printed TiO2/Chitin/Cellulose Composite with Ordered Porous Structures.

In this study, we printed three-dimensional (3D) titanium dioxide (TiO2)/chitin/cellulose composite photocatalysts with ordered interconnected porous structures. Chitin microparticles were mixed with cellulose in the N-methylmorpholine-N-oxide (NMMO) solution to prepare the printing "ink". TiO2 nanoparticles were embedded on the chitin/cellulose composite in the NMMO removal process by water before the freeze-drying process to build the 3D cellulosic photocatalysts with well-defined porous structures. The 3D-printed TiO2/chitin/cellulose composites were characterized by X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), and Energy Disperse Spectroscopy (EDS). The XRD and FTIR analyses showed that chitin had an interference effect on the crystal regeneration of cellulose and resulted in a large amount of amorphous phase. The SEM images show that the printed cellulosic strands had a hollow structure, and the EDS analysis showed that TiO2 nanoparticles were embedded on the chitin/cellulose composite surfaces. In the photocatalytic degradation process of methylene blue (MB) dye in an aqueous solution, the TiO2/chitin/cellulose 3D composite photocatalysts demonstrated efficient MB degradation activities with excellent reusability and stability, in which the chitin content performed the function of adjusting the MB degradation efficiency.

Event-centric multi-modal fusion method for dense video captioning.

Dense video captioning aims to automatically describe several events that occur in a given video, which most state-of-the-art models accomplish by locating and describing multiple events in an untrimmed video. Despite much progress in this area, most current approaches only encode visual features in the event location phase and they neglect the relationships between events, which may degrade the consistency of the description in the identical video. Thus, in the present study, we attempted to exploit visual-audio cues to generate event proposals and enhance event-level representations by capturing their temporal and semantic relationships. Furthermore, to compensate for the major limitation of not fully utilizing multimodal information in the description process, we developed an attention-gating mechanism that dynamically fuses and regulates the multi-modal information. In summary, we propose an event-centric multi-modal fusion approach for dense video captioning (EMVC) to capture the relationships between events and effectively fuse multi-modal information. We conducted comprehensive experiments to evaluate the performance of EMVC based on the benchmark ActivityNet Caption and YouCook2 data sets. The experimental results showed that our model achieved impressive performance compared with state-of-the-art methods.

Structure Optimization of Cellulose Nanofibers/Poly(Lactic Acid) Composites by the Sizing of AKD.

Recently, cellulose nanofibers (CNF) are used as one novel fillers to reinforce poly(lactic acid) (PLA) matrix and form PLA green nanocomposites. In the present work, alkyl ketene dimer (AKD) was used as the sizing of CNF to improve the interfacial compatibility between the hydrophilic CNF and the hydrophobic PLA. The interactions between the AKD and CNF were characterized by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR), which showed the formation of ketone ester structure between AKD and the hydroxyl groups of CNF. Thermo gravimetric analysis (TGA) showed the little reduced thermal stability of the AKD-CNF/PLA composites. The AKD-CNF/PLA morphology has rough surfaces due to the incorporation of cellulose nanofibers. The mechanical properties of AKD-CNF/PLA were tested by tensile testing, which discovered more AKD-CNF content enhances stress-strain performance. The highest tensile strength of composites was obtained for PLA with 5.0 wt.% AKD-cellulose, which is almost nine times higher than that of the pure PLA.

Tribological, cytotoxicity and antibacterial properties of graphene oxide/carbon fibers/polyetheretherketone composite coatings on Ti-6Al-4V alloy as orthopedic/dental implants.

In this work, graphene oxide/carbon fibers/polyetheretherketone (GO/CF/PEEK) composite coatings on Ti-6Al-4V (TC4) alloy were fabricated by electrostatic powder spraying method. The coatings with 0.02 wt% GO and 25 wt% CF were made to improve the wear resistance, cytocompatibility and antibacterial properties of the TC4 as orthopedic/dental implants. The physicochemical properties involving coating thickness, Vickers hardness, micromorphology, phase structures and contact angles were investigated. The results indicated that the GO/CF/PEEK coatings can significantly decrease the coefficient of friction (COF) (from 0.433 ± 0.017 to 0.085 ± 0.008) and enhance the wear resistance of TC4 alloy during the wet friction process in sliding contact with a Si3N4 ball. The results showed that few scratches appeared on the GO/CF/PEEK coating. As the in vitro cytotoxicity test by murine fibroblast L929 cells shown, the GO/CF/PEEK coating revealed good cytocompatibility. More importantly, GO/CF/PEEK coating exhibited excellent suppression toward Staphylococcus aureus (S. aureus) owing to the antibacterial nature of GO. Therefore, the GO/CF/PEEK composite coated TC4 could be considered as a prospective orthopedic/dental implant material for bone tissue engineering.

Solvolysis kinetics of three components of biomass using polyhydric alcohols as solvents.

The solvolysis behavior and reaction kinetics of the three components of biomass (cellulose, hemicelluloses and lignin) liquefied in polyhydric alcohols (PEG 400 or glycerol) were investigated in this paper. Three stages were observed during the solvolysis process and the main degradation stage could be further divided into two zones. The influences of solvents on the liquefaction process of three main components were compared. Based on Starink and Malek methods, kinetic parameters and mechanism functions were obtained. The derived average activation energy of cellulose, hemicellulose and lignin were 108.73, 95.66 and 94.13kJmol-1 in PEG 400, while the values were 102.16, 77.43 and 89.10kJmol-1 in glycerol, respectively. Higher efficiency was observed when using glycerol as solvent, which could be ascribed to the higher polarity value of glycerol. The conversion curves calculated with obtained mechanism models and kinetic parameters were in good agreement with the experimental data.

Effects of copolymer composition, film thickness, and solvent vapor annealing time on dewetting of ultrathin block copolymer films.

Effects of copolymer composition, film thickness, and solvent vapor annealing time on dewetting of spin-coated polystyrene-block-poly(methyl methacrylate) (PS-b-PMMA) films (<20nm thick) were mainly investigated by atomic force microscopy. Surface chemical analysis of the ultrathin films annealed for different times were performed using X-ray photoelectron spectroscopy and contact angle measurement. With the annealing of acetone vapor, dewetting of the films with different thicknesses occur via the spinodal dewetting and the nucleation and growth mechanisms, respectively. The PS-b-PMMA films rupture into droplets which first coalesce into large ones to reduce the surface free energy. Then the large droplets rupture into small ones to increase the contact area between PMMA blocks and acetone molecules resulting from ultimate migration of PMMA blocks to droplet surface, which is a novel dewetting process observed in spin-coated films for the first time.

Kinetic and product composition study on the cellulose liquefaction in polyhydric alcohols.

The liquefaction process of cellulose in polyhydric alcohols (PEG 400 and glycerol) was studied by TG-FTIR. Three stages were observed during the solvolysis process and the main liquefaction stage could be further divided into two zones. The differences of liquefaction behavior of cellulose in the two solvents were compared, and the functional groups of volatiles produced by solvolysis were also evaluated. A step-wise procedure based on iso-conversional and Master-plots methods was used for the kinetic and mechanism analysis of the main liquefaction stage. The calculation results based on the kinetic model were in agreement with the experimental data of the conversion rate. The kinetic parameters and mechanism functions between cellulose liquefaction in PEG400 and in glycerol were quite different, which verified that solvolysis behavior and reaction process were seriously influenced by solvent species. Finally, the detailed types of volatiles and product distribution were measured by Py-GC-MS.