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Cartilage defects frequently occur around the knee joint yet cartilage has limited self-repair abilities. Hydrogel scaffolds have excellent potential for use in tissue engineering. Therefore, the aim of the present study was to assess the ability of silk fibroin (SF) hydrogel scaffolds incorporated with chitosan (CS) nanoparticles (NPs) to repair knee joint cartilage defects. In the present study, composite systems of CS NPs incorporated with transforming growth factor-β1 (TGF-β1; TGF-β1@CS) and SF incorporated with bone morphogenetic protein-2 (BMP-2; TGF-β1@CS/BMP-2@SF) were developed and characterized with respect to their size distribution, zeta potential, morphology, and release of TGF-β1 and BMP-2. Bone marrow stromal cells (BMSCs) were co-cultured with TGF-β1@CS/BMP-2@SF extracts to assess chondrogenesis in vitro using a cell counting kit-8 assay, which was followed by in vivo evaluations in a rabbit model of knee joint cartilage defects. The constructed TGF-β1@CS/BMP-2@SF composite system was successfully characterized and showed favorable biocompatibility. In the presence of TGF-β1@CS/BMP-2@SF extracts, BMSCs exhibited normal cell morphology and enhanced chondrogenic ability both in vitro and in vivo, as evidenced by the promotion of cell viability and the alleviation of cartilage defects. Thus, the TGF-β1@CS/BMP-2@SF hydrogel developed in the present study promoted chondrogenic ability of BMSCs both in vivo and in vitro by releasing TGF-β1 and BMP-2, thereby offering a novel therapeutic strategy for repairing articular cartilage defects in knee joints.

Valley degree of freedom in the first Brillouin zone of Bloch electrons offers an innovative approach to information storage and quantum computation. Broken inversion symmetry together with the presence of time-reversal symmetry endows Bloch electrons non-zero Berry curvature and orbital magnetic moment, which contribute to the valley Hall effect and optical selection rules in valleytronics. Furthermore, the emerging transition metal dichalcogenides (TMDs) materials naturally become the ideal candidates for valleytronics research attributable to their novel structural, photonic and electronic properties, especially the direct bandgap and broken inversion symmetry in the monolayer. However, the mechanism of inter-valley relaxation remains ambiguous and the complicated manipulation of valley predominantly incumbers the realization of valleytronic devices. In this review, we systematically demonstrate the fundamental properties and tuning strategies (optical, electrical, magnetic and mechanical tuning) of valley degree of freedom, summarize the recent progress of TMD-based valleytronic devices. We also highlight the conclusion of present challenges as well as the perspective on the further investigations in valleytronics.

Background It has been well documented that obesity is closely associated with metabolic syndrome (MetS). Although body mass index (BMI) is the most frequently used method to assess overweightness and obesity, this method has been criticized because BMI does not always reflect true body fatness, which may be better evaluated by assessment of body fat and fat-free mass. The objective of this study was to investigate the best indicator to predict the presence of MetS among fat mass index, BMI and percentage of body fat (BF %) and determine its optimal cut-off value in the screening of MetS in practice. Methods A cross-sectional study of 1698 subjects (aged 20–79 years) who participated in the annual health check-ups was employed. Body composition was measured by bioelectrical impedance analysis (BIA). Fat mass index (FMI) was calculated. Sex-specific FMI quartiles were defined as follows: Q1: <4.39, Q2:4.39- < 5.65, Q3:5.65- < 7.03, Q4:≥7.03,in men; and Q1:<5.25, Q2:5.25- < 6.33, Q3:6.33- < 7.93,Q4:≥7.93, in women. MetS was defined by National Cholesterol Education Program/Adult Treatment Panel III criteria. The association between FMI quartiles and MetS was assessed using Binary logistic regression. Receiver operating curve(ROC) analysis was used to determine optimal cutoff points for BMI,BF% and FMI in relation to the area under the curve(AUC),sensitivity and specificity in men and women. Results The adjusted odds ratios (95% CI) for the presence of MetS in the highest FMI quartile versus lowest quartile were 79.143(21.243-294.852) for men( P  < 0.01) and 52.039(4.144-653.436) for women( P  < 0.01) after adjusting age, BMI, BF%, TC, LDL, CRP, smoking status and exercise status, and the odds ratios were 9.166(2.157-38.952) for men( P  < 0.01) and 25.574(1.945-336.228) for women( P  < 0.05) when WC was also added into the adjustment. It was determined that BMI values of 27.45 and 23.85 kg/m 2 , BF% of 23.95% and 31.35% and FMI of 7.00 and 7.90 kg/m 2 were the optimal cutoff values to predict the presence of MetS among men and women according to the ROC curve analysis. Among the indicators used to predict MetS, FMI was the index that showed the greatest area under the ROC curve in both sexes. Conclusions Higher FMI levels appear to be independently and positively associated with the presence of MetS regardless of BMI and BF%. FMI seems to be a better screening tool in prediction of the presence of metabolic syndrome than BMI and percentage of body fat in men and women.

Nonlinear optical effects in layered two-dimensional transition metal chalcogenides have been extensively explored recently because of the promising prospect of the nonlinear optical effects for various optoelectronic applications. However, these materials possess sizable bandgaps ranging from visible to ultraviolet region, so the investigation of narrow-bandgap materials remains deficient. Here, we report our comprehensive study on the nonlinear optical processes in palladium diselenide (PdSe 2 ) that has a near-infrared bandgap. Interestingly, this material exhibits a unique thickness-dependent second harmonic generation feature, which is in contrast to other transition metal chalcogenides. Furthermore, the two-photon absorption coefficients of 1–3 layer PdSe 2 ( β  ~ 4.16 × 10 5 , 2.58 × 10 5 , and 1.51 × 10 5  cm GW −1 ) are larger by two and three orders of magnitude than that of the conventional two-dimensional materials, and giant modulation depths ( α s  ~ 32%, 27%, and 24%) were obtained in 1–3 layer PdSe 2 . Such unique nonlinear optical characteristics make PdSe 2 a potential candidate for technological innovations in nonlinear optoelectronic devices. Strong nonlinearities in 2D materials can lead to interesting applications in optoelectronics. Here the authors investigate the optical nonlinearity of palladium diselenide, determine the layer dependent two photon absorption efficiency and the saturable absorption modulation depth.

This paper presents a comparative study on natural indigo and indirubin in terms of molecular structures and spectral properties by using both computational and experimental methods. The spectral properties were analyzed with Fourier transform infrared (FTIR), Raman, UV-Visible, and fluorescence techniques. The density functional theory (DFT) method with B3LYP using 6-311G(d,p) basis set was utilized to obtain their optimized geometric structures and calculate the molecular electrostatic potential, frontier molecular orbitals, FTIR, and Raman spectra. The single-excitation configuration interaction (CIS), time-dependent density functional theory (TD-DFT), and polarization continuum model (PCM) were used to optimize the excited state structure and calculate the UV-Visible absorption and fluorescence spectra of the two molecules at B3LYP/6-311G(d,p) level. The results showed that all computational spectra agreed well with the experimental results. It was found that the same vibrational mode presents a lower frequency in indigo than that in indirubin. The frontier molecular orbital analysis demonstrated that the UV-Visible absorption and fluorescence bands of indigo and indirubin are mainly derived from π → π* transition. The results also implied that the indigo molecule is more conjugated and planar than indirubin, thereby exhibiting a longer maximum absorption wavelength and stronger fluorescence peak.

Highlights The controllable fabrication methods, the unique properties, and relative applications of 2D heterostructures were summarized. The generation and detection of interlayer excitons in 2D heterostructures with type II band alignment indicate a longer lifetime and larger binding energy than intralayer excitons. The advances in magnetic tunneling junctions based on 2D heterostructures can be applied in spintronic devices to realize spin filtering. With a large number of researches being conducted on two-dimensional (2D) materials, their unique properties in optics, electrics, mechanics, and magnetics have attracted increasing attention. Accordingly, the idea of combining distinct functional 2D materials into heterostructures naturally emerged that provides unprecedented platforms for exploring new physics that are not accessible in a single 2D material or 3D heterostructures. Along with the rapid development of controllable, scalable, and programmed synthesis techniques of high-quality 2D heterostructures, various heterostructure devices with extraordinary performance have been designed and fabricated, including tunneling transistors, photodetectors, and spintronic devices. In this review, we present a summary of the latest progresses in fabrications, properties, and applications of different types of 2D heterostructures, followed by the discussions on present challenges and perspectives of further investigations.

Stomach adenocarcinoma (STAD), the most prevalent histological subtype of gastric cancer, exhibits high heterogeneity and poor prognosis, posing significant therapeutic challenges. Parthanatos, a distinct form of regulated cell death mediated by poly (ADP-ribose) polymerase-1 (PARP-1), has been implicated in tumor biology and therapeutic resistance; however, the role of parthanatos-associated genes (PRGs) in STAD remains largely unexplored. In this study, we performed a comprehensive multi-omics analysis integrating transcriptomic, genomic, and clinical data from public databases to delineate the molecular landscape of PRGs in STAD. Unsupervised clustering revealed distinct PRG-related molecular subtypes with significant differences in clinical outcomes, immune infiltration profiles, and biological pathway activation. Based on machine learning algorithms, we established and validated a novel PRG-based prognostic signature, which demonstrated robust predictive performance. Moreover, single-cell RNA sequencing and in vitro functional assays were conducted to explore cellular heterogeneity and gene function. Notably, in vitro experiments, including western blot, colony formation, CCK-8, and Transwell assays, confirmed that one key PRG, COL8A1, promotes STAD cell proliferation and migration. Collectively, our findings highlight the clinical and biological significance of PRGs in STAD, offering novel biomarkers and potential therapeutic targets for STAD precision treatment.

The incidence of hyperuricemia (HUA) and gout continuously increases and has become a major public health problem. The gut microbiota, which colonizes the human intestine, has a mutually beneficial and symbiotic relationship with the host and plays a vital role in the host’s metabolism and immune regulation. Structural changes or imbalance in the gut microbiota could cause metabolic disorders and participate in the synthesis of purine-metabolizing enzymes and the release of inflammatory cytokines, which is closely related to the occurrence and development of the metabolic immune disease HUA and gout. The gut microbiota as an entry point to explore the pathogenesis of HUA and gout has become a new research hotspot. This review summarizes the characteristics of the gut microbiota in patients with HUA and gout. Meanwhile, the influence of different dietary structures on the gut microbiota, the effect of the gut microbiota on purine and uric acid metabolism, and the internal relationship between the gut microbiota and metabolic endotoxemia/inflammatory factors are explored. Moreover, the intervention effects of probiotics, prebiotics, and fecal microbial transplantation on HUA and gout are also systematically reviewed to provide a gut flora solution for the prevention and treatment of related diseases.

Existing studies have focused on post-traumatic stress disorder (PTSD) after surgery in patients with knee osteoarthritis (KOA), whereas PTSD in non-operated elderly KOA patients has not been adequately studied. The aim was to assess the current status of PTSD and its influencing factors among non-surgical elderly KOA patients. From October to November 2021, a cross-sectional study was conducted among 320 consecutive patients aged ≥ 65 years with radiologically confirmed KOA and no history of knee surgery or psychiatric disorders, recruited from three community hospitals in Changsha, Hunan Province. A total of 314 participants completed validated assessments for PTSD (PTSD Checklist-Civilian Version), pain (Numerical Rating Scale), anxiety (Generalized Anxiety Disorder Scale), depression (Patient Health Questionnaire-9), and social support (Social Support Rating Scale). Data were analyzed using non-parametric tests and Spearman correlation. Structural equation modeling (SEM) was performed with Amos 24.0, employing maximum likelihood estimation and 1000 bootstrap samples to test mediation effects. Among 314 analyzed participants (mean age 72.91 ± 6.384 years; 60.80% female and 39.20% males), PTSD prevalence was 18.20%. Significantly higher PTSD risk was associated with low education levels ( Z =−2.398, P  = 0.016), low salaries ( H = −2.398, P  = 0.005), unemployed patients ( H  = 10.030, P  = 0.007), no exercise ( H  = 9.328, P  = 0.025), smoking ( Z = −2.504, P  = 0.012) and no leisure activities ( Z =−2.074, P  = 0.038). Structural equation modeling revealed a direct effect of depression on PTSD with the path coefficient of 0.701 (95% CI 0.518–0.879, P  = 0.001) and an indirect effect of pain on PTSD through social support with the path coefficient of −0.014 (95% CI −0.049 to −0.001, P  = 0.035 < 0.05). Non-surgical elderly patients with knee osteoarthritis exhibit clinically significant post-traumatic stress disorder rates (18.20%), primarily driven by depression and mediated through pain-social support pathways. These findings underscore the need for integrated biopsychosocial interventions targeting pain management, mental health screening, and social support enhancement in this population.

Social commerce has rapidly developed as a new area in electronic commerce field and has risen the attention of both researchers and practitioners. This paper investigated the intellectual structure, development, and evolution of social commerce quantitatively to provide a systematic review of the current state of the social commerce literature. We used a visualization tool called CiteSpace and mapped our result into the I-model for classification. According to 503 articles focusing on social commerce with associated 12,089 references, we have identified the most influential authors, institutions, publications, keywords, and references in this field, as well as the hot topics and future trends. In addition, we have developed the visual network of these research elements through CiteSpace for a deep level analysis, especially for future research trends prediction. Finally, our combination of bibliometric methods and a systematic review makes for a better understanding in the development of social commerce for both researchers and practitioners.