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Nitrogen is widely believed to accelerate the diamond growth by chemical vapor deposition (CVD). While there is currently no consensus on the reaction mechanism of nitrogen increasing the growth rate of CVD diamond. In this work, we have proposed a chemical adsorption model formed by substitutional nitrogen on the H-terminated surface of diamond. The first principles calculations based on density functional theory are used to systematically study the effects of substitutional nitrogen on several key features (i.e., surface absorption energy, geometric structure, atomic charge, electron bond population, and electron density) of the H-terminated surfaces. The results indicate that nitrogen substituted on the H-terminated surface are probably more favorable for hydrogen desorption, which can not only affect the properties of directly bonding adjacent species, but also cause changes in the geometric and electronic properties around the surface by electron transfer or forming additional covalent bonds. Furthermore, compared with single nitrogen doping, the co-doped structures formed by adding boron or phosphorus at a relatively low N/H ratio on the H-terminated surface could enhance or weaken the stability of the diamond surface, that is, weaken or enhance the desorption process of hydrogen. It is therefore proved the existence of a regulatory effect on the threshold concentration required for nitrogen to accelerate diamond growth. [Display omitted] • The substitutional N on the H-Ter-D (100) surface is more stable than NH and NH 2. • The concentration of N on the H-Ter-D (100) surface is higher than that of NH and NH 2. • The N on the H-Ter-D (100) surface has a stronger regulatory effect on H desorption. • The co-doped structures of N B or N P have an opposite effect on H desorption. • It is proved the existence of the threshold concentration required for N to accelerate diamond growth. [ABSTRACT FROM AUTHOR]

The strong temperature dependence of the contribution of nitrogen to diamond growth enhancement by microwave plasma chemical vapor deposition (MPCVD) have been firstly reported and systematically studied. Generally, an enhanced hydrogen desorption from the growing surface induced by the incorporated nitrogen atoms in diamond sublayer has been successfully used to explain the weak temperature depended growth enhancement of diamond by nitrogen addition, but cannot be employed to explain the observed strong temperature dependence of nitrogen contribution to diamond growth enhancement observed in this work. This indicates a significant change of surface kinetics of diamond growth induced by nitrogen addition should be occurred around 700 °C where a maximum value achieved. At this relative low temperature, the growing surface sites should be almost fully covered with hydrogen atoms with relative low nitrogen incorporated in the diamond. The adsorbed nitrogen may then make a contribution to promote hydrogen desorption, which is believed to play a dominant role in affecting the contribution of nitrogen. Experimental and calculation results do show that both the nitrogen adsorbed on the growing surface and incorporated in the sublayer may have different contribution to the growth rate enhancement, resulting in strong and weak temperature dependence, respectively. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • A multifunctional composite Ti-Ta@Sr substrates is successfully fabricated. • The rat model of diabetic bone defect was successfully constructed. • The Ti-Ta@Sr which we created possess potential to remove reactive oxygen species and promote bone formation. • The coating is beneficial for bone formation in diabetic rats. The aging population is closely associated with chronic metabolic diseases, including diabetes, hypertension, and other metabolic disorders. Metabolic dysfunction is a primary characteristic of diabetic patients, which can impair cellular response to insulin and lead to increased production of reactive oxygen species (ROS), hindering bone healing. Therefore, the development of multifunctional titanium (Ti) implants with the ability to eliminate reactive oxygen and promote bone formation is the optimal strategy to address this issue. In this study, we designed a thioctic acid(Ta) coating loaded with strontium(Sr), forming a strong bond with the Ti implant (Ti-Ta@Sr). During treatment, sulfuric acid demonstrated the ability to release monomers in the early stages, effectively eliminating excess reactive oxygen produced in high-glucose environments and regulating the diabetic microenvironment. The delayed in-situ release of strontium ions also enhanced osteogenic differentiation efficiency. Both in vivo and in vitro experiments confirmed that Ti-Ta@Sr significantly restored the osteogenic capacity and proliferation of osteoblasts under high-glucose conditions. These advantages make Ti-Ta@Sr a promising candidate material for orthopedic implants, suitable for repairing bone defects in diabetic patients. [ABSTRACT FROM AUTHOR]

Silicon vacancies in diamond, one of the most promising single photon sources, is difficult to be achieved in a controlled and reproducible way due to complicated doping behavior of silicon in diamond by microwave plasma CVD. In this work, the underneath mechanism of silicon vacancies formed by unintentional silicon (The silicon source is SiO 2 from the microwave plasma CVD quartz window) doping in diamond was investigated from the view of growing surface kinetics through a series of experiments. During deposition, the addition of N 2 to the CH 4 -H 2 reaction gas mixture is beneficial to the formation of silicon vacancies in diamond from unintentional silicon doping, and the addition of a minor amount of oxygen will enhance the plasma etching. The increased number of the dangling bonds is beneficial to the formation of silicon vacancies and nitrogen vacancies in diamond, while excessive oxygen will passivation the dangling bonds and thus inhibit the formation of vacancies. Finally, the vertical distributions of the surface topography, growth rate, intensity of photoluminescence of NV and SiV color centers doped in the diamond film, are measured with high spatial resolution on growth surface, which are also related to the plasma electron temperature and density. These findings are of importance for searching of optimal growth regimes of NV and SiV doped single crystals by microwave plasma CVD. • The addition of nitrogen to the growth gas is beneficial to the formation of SiV−. • A minor amount of oxygen promotes while excessive oxygen inhibits the formation of NV− and SiV−. • The growth and distribution of NV− and SiV− in diamonds are related to the plasma on the surface of the substrate. [ABSTRACT FROM AUTHOR]

Rapid urbanization has made road construction and maintenance imperative, but detecting road diseases has been time-consuming with limited accuracy. To overcome these challenges, we propose an efficient YOLOv7 road disease detection model. Our approach involves integrating MobilieNetV3 as the backbone feature extraction network to reduce the network's parameters and computational requirements. Additionally, we introduce the BRA attention module into the spatial pyramid pooling module to eliminate redundant information and enhance the network's feature representation capability. Moreover, we utilize the F-ReLU activation function in the backbone network, expanding the convolutional layers' receptive field range. To optimize the model's boundary loss, we employ the Wise-IoU loss function, which places more emphasis on the quality of ordinary samples and enhances the overall performance and generalization ability of the network. Experimental results demonstrate that our improved detection algorithm achieves a higher recall rate and mean average precision (mAP) on the public dataset (RDD) and the NJdata dataset in Nanjing's urban area. Specifically, compared to YOLOv7, our model increases the recall rate and mAP on RDD by 3.3% and 2.6%, respectively. On the NJdata dataset, our model improves the recall rate and mAP by 1.9% and 1.3%, respectively. Furthermore, our model reduces parameter and computational requirements by 30% and 22.5%, respectively, striking a balance between detection accuracy and speed. In conclusion, our road disease detection model presents an effective solution to address the challenges associated with road disease detection in urban areas. It offers improved accuracy, efficiency, and generalization capabilities compared to existing models. [ABSTRACT FROM AUTHOR]

[Display omitted] • A biocompatible, injectable, and lesion-localized hydrogel loaded with extracellular matrix (ECM) was developed. • Stimulation of mesenchymal stem cells with TNF-α, IL-6, and IFN-γ enhanced the quality and biological function of the ECM. • The engineered ECM hydrogels effectively maintained chondrocyte homeostasis. • The engineered ECM hydrogels preserved cellular homeostasis by augmenting mitochondrial energy metabolism. • ECM derived from various inflammatory cytokine pre-treatments displayed distinct functional strengths and weaknesses, with IFN-γ-ECM demonstrating superior efficacy. Cartilage damage and degeneration are fundamental pathological features of osteoarthritis (OA), attributed largely to disruptions in chondrocyte homeostasis. Tissue engineering employing functional bioactive materials presents a promising avenue for cartilage regeneration and repair. Particularly, extracellular matrix (ECM) produced by mesenchymal stem cells (MSCs) is gaining traction in the field of tissue engineering and scaffold-based regenerative therapies due to its robust bioactivity and excellent biocompatibility. In this study, we utilized specific inflammatory cytokines associated with OA as stimulators to optimize the MSC-derived secretome. Our in vitro experiments demonstrated that the engineered ECM effectively inhibited early chondrocyte apoptosis, reversed cellular senescence, and maintained anabolic-catabolic equilibrium. Moreover, we developed aldehyde- and methacrylic anhydride-modified hyaluronic acid hydrogels incorporated with ECM (ECM@AH) using photo-cross-linking techniques. The affinity of these ECM-functionalized hydrogels for degraded cartilage was confirmed through in situ cartilage lesion localization experiments in the knee joints of rat OA models. Further in vitro analysis revealed that the engineered ECM@AH, especially IFN-γ-ECM@AH, sustains chondrocyte homeostasis by restoring mitochondrial energy metabolism. Animal studies demonstrated that ECM@AH, localized to cartilage lesions, could reverse cartilage matrix degradation and promote cartilage repair, underscoring the potential of this biomaterial in OA treatment. [ABSTRACT FROM AUTHOR]

This study introduces a novel 3D scaffold for bone regeneration, composed of silk fibroin, chitosan, nano-hydroxyapatite, LL-37 antimicrobial peptide, and pamidronate. The scaffold addresses a critical need in bone tissue engineering by simultaneously combating bone infections and promoting bone growth. LL-37 was incorporated for its broad-spectrum antimicrobial properties, while pamidronate was included to inhibit bone resorption. The scaffold's porous structure, essential for cell infiltration and nutrient diffusion, was achieved through a freeze-drying process. In vitro assessments using SEM and FTIR confirmed the scaffold's morphology and chemical integrity. Antimicrobial efficacy was tested against pathogens of Staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa (P. aeruginosa). In vivo studies in a murine model of infectious bone defect revealed the scaffold's effectiveness in reducing inflammation and bacterial load, and promoting bone regeneration. RNA sequencing of treated specimens provided insights into the molecular mechanisms underlying these observations, revealing significant gene expression changes related to bone healing and immune response modulation. The results indicate that the scaffold effectively inhibits bacterial growth and supports bone cell functions, making it a promising candidate for treating infectious bone defects. Future studies should focus on optimizing the release of therapeutic agents and evaluating the scaffold's clinical potential. [Display omitted] [ABSTRACT FROM AUTHOR]

Organic-inorganic hybrid perovskite solar cells (PSCs) have become a potential photovoltaic device, because of their excellent photoelectric performance and low cost. However, there are many defects on the surface and grain boundaries of perovskite materials, such as vacancies and interstitials, which can become channels for ion migration. The instability of PSCs due to ion migration severely reduces the device performance such as hysteresis and stability, even with encapsulation. In this paper, 2-thiophenecarboxamide(2-TC) is introduced as an interface passivator. We found that the amine groups in 2-TC could cooperate with I− through hydrogen bond (NH⋯I) and the thiophene, carbonyl group could cooperate with Pb2+, the grain boundary defects generated by lead and iodine vacancies are passivated, thereby inhibiting ion migration. Through calculation the activation energy (E A) for ion migration is increased after 2-TC modification, suggesting the inhibition of ion migration. Consequently, the power conversion efficiency (PCE) of 2-TC modified PSCs increased from 19.07 % to 22.03 % and the hysteresis is reduced by more than 58 %. After being stored in the air with 45 % humidity for 240 h, the PCE of the modified devices remained above 90 % of the original compared to the control devices. • Various cationic and anionic defects are passivated by carbonyl (C=O), thiophene groups, and amino groups in 2-TC through coordination and hydrogen bonding. • The 2-TC layer increases the activation energy required for ion migration, inhibits ion migration, and reduces hysteresis behavior. • The strong bonding of 2-TC plays a role in passivating surface and grain boundary defects caused by lead and iodine vacancies, blocking the channels required for ion migration, inhibiting ion migration, reducing hysteresis, and improving carrier transport and water stability. [ABSTRACT FROM AUTHOR]

The injectable micro-nano hydrogel we developed can be administered into articular cavities using a minimally invasive puncture needle. It undergoes degradation facilitated by MMP13, leading to the controlled release of celecoxib. This property effectively mitigates the inflammatory response and precisely reverses the OA process. [Display omitted] • The significance of MMP13 in osteoarthritis precise interventions was discussed. • Adapting to inflammatory levels and MMP13 changes, the microsphere achieves a responsive release of celecoxib. • This controllable drug delivery system holds promise for precise therapeutic interventions in diverse degenerative diseases. Osteoarthritis (OA) is characterized by cartilage degradation, inflammatory responses, and osteophyte formation. Matrix metalloproteinase 13 (MMP13) is a hallmark of OA development, and increased MMP13 expression is closely associated with extracellular matrix degradation. MMP13 expression varies significantly at different stages of OA progression. While cyclooxygenase 2 (COX-2) inhibitors are commonly used to treat OA, their long-term systemic administration increases the risks of adverse effects. Therefore, with the aim of achieving localized and responsive delivery of the COX-2 inhibitor celecoxib, the current study investigated an innovative MMP13-responsive micro-nano hydrogel microsphere system. Celecoxib-loaded cationic liposomes are non-covalently attached within the microsphere, enabling controlled drug release for OA treatment. In an OA environment with elevated MMP13 expression, the system is degraded via the action of MMP13 substrate peptide (MMP13sp), facilitating accelerated release of drug-loaded liposomes to improve the inflammatory microenvironment and treat OA rapidly. Compared to a phosphate-buffered saline solution with hyaluronidase (HAase), the prepared hyaluronic acid methacrylate microspheres HAMA/MMP13sp/Lipo@celecoxib exhibited rapid degradation in a solution containing a physiological concentration of MMP13/HAase, demonstrating specific enzyme responsiveness for precise anti-inflammatory drug release. The MMP13-responsive hydrogel microsphere system achieves intelligent and controllable drug release in OA, effectively decelerating disease progression and promoting articular cartilage repair. [ABSTRACT FROM AUTHOR]