Probing the Anti-Corrosion Behavior of X65 Steel Underwater FSW Joint in Simulated Seawater

To detect the corrosion resistance of a friction stud welding (FSW) joint in simulated seawater (a 3.5 wt% NaCl solution), the pulse electrochemical deposition method was used for electroplating Ni coating with different duty ratios (50%, 80%, and 100%) on the surface of FSW joint. The microstructure and surface structure of the coating were observed by micro-spectroscopy and other characterization methods. The corrosion behavior of the coating was analyzed by means of macroscopic electrochemical testing. The local corrosion law of joint surface and coating surface defects were innovatively explored by using micro-zone electrochemical scanning system. The coating characterization results showed that, as the duty ratio continues to increase, the coating surface becomes denser and smoother, and the corrosion products such as Fe2O3, Fe3O4, and FeOOH are generated. The results of macroscopic electrochemical experiment indicated that the coating with 100% duty ratio has the lowest corrosion current density and the maximum polarization resistance. The scanning vibrating electrode technique results showed that the corrosion current density in the defect area is higher than that in the coating area, and the maximum corrosion current density decreases with the increase of duty ratio. The localized electrochemical impedance spectroscopy results indicated that the localized impedance at the welded zone was the largest, and with the increase of the pulse duty ratio, the impedance diffusion in the defect area was decreasing.

In Vivo Study of Nasal Bone Reconstruction with Collagen, Elastin and Chitosan Membranes in Abstainer and Alcoholic Rats

The aim of the present study was to evaluate the use of collagen, elastin, or chitosan biomaterial for bone reconstruction in rats submitted or not to experimental alcoholism. Wistar male rats were divided into eight groups, submitted to chronic alcohol ingestion (G5 to G8) or not (G1 to G4). Nasal bone defects were filled with clot in animals of G1 and G5 and with collagen, elastin, and chitosan grafts in G2/G6, G3/G7, and G4/G8, respectively. Six weeks after, all specimens underwent radiographic, tomographic, and microscopic evaluations. Bone mineral density was lower in the defect area in alcoholic animals compared to the abstainer animals. Bone neoformation was greater in the abstainer groups receiving the elastin membrane and in abstainer and alcoholic rats receiving the chitosan membrane (15.78 ± 1.19, 27.81 ± 0.91, 47.29 ± 0.97, 42.69 ± 1.52, 13.81 ± 1.60, 18.59 ± 1.37, 16.54 ± 0.89, and 37.06 ± 1.17 in G1 to G8, respectively). In conclusion, osteogenesis and bone density were more expressive after the application of the elastin matrix in abstainer animals and of the chitosan matrix in both abstainer and alcoholic animals. Chronic alcohol ingestion resulted in lower bone formation and greater formation of fibrous connective tissue.

Effect of Type 1 Collagen Bioactive Material Scaffold on the Recovery of Sports-Caused Cartilage Injury

This study was aim to investigate the effect of type 1 collagen (Col I) bioactive scaffold on regeneration and repair of motor cartilage injury. Fifteen New Zealand rabbits were randomly divided into sham operation group (Sham group, only cartilage was exposed, no defect was made), model group Focal cortical dysplasias (FCD) group, cartilage defect model], and treatment group (Col I group, cartilage defect + Col I bioactive scaffold treatment). The cartilage tissue of each group was detected 16 weeks after the operation. Immunohistochemistry and Western Blot were adopted to detect the expression of cartilage related proteins in each group. The results showed that Col I bioactive scaffold could repair the gross morphology of cartilage defect, promote the regeneration and repair of chondrocytes in defect area, and reduce the mast cells in defect area. Western Blot detection of the expression of signal pathway marker proteins showed that expression of Wnt protein, β-catenin protein, and phosphofructokinase-1 (PFK-1) protein in the FCD group were significantly reduced than Sham group (P < 0.05), while the expression of phosphoenolpyruvate carboxykinase 1 (PEPCK1) protein was significantly increased (P < 0.05). Expression of Wnt protein, β-catenin protein, and PFK-1 protein in Col I group increased significantly versus FCD group (P < 0.05), while the expression of PEPCK1 protein significantly decreased (P < 0.05). In conclusion, Col I bioactive scaffolds could regenerate and repair cartilage defects, and the mechanism may be related to Wnt signaling pathway and glycolysis/gluconeogenesis pathway.

Local delivery of hydrogel encapsulated vascular endothelial growth factor for the prevention of medication-related osteonecrosis of the jaw

The anti-angiogenic effects of bisphosphonates have been hypothesized as one of the major etiologic factors in the development of medication-related osteonecrosis of the jaw (MRONJ), a severe debilitating condition with limited treatment options. This study evaluated the potential of a gelatine-hyaluronic acid hydrogel loaded with the angiogenic growth factor, vascular endothelial growth factor (VEGF), as a local delivery system to aid in maintaining vascularization in a bisphosphonate-treated (Zoledronic Acid) rodent maxillary extraction defect. Healing was assessed four weeks after implantation of the VEGF-hydrogel into extraction sockets. Gross examination and histological assessment showed that total osteonecrosis and inflammatory infiltrate was significantly reduced in the presence of VEGF. Also, total vascularity and specifically neovascularization, was significantly improved in animals that received VEGF hydrogel. Gene expression of vascular, inflammatory and bone specific markers within the defect area were also significantly altered in the presence of VEGF. Furthermore, plasma cytokine levels were assessed to determine the systemic effect of locally delivered VEGF and showed similar outcomes. In conclusion, the use of locally delivered VEGF within healing extraction sockets assists bone healing and prevents MRONJ via a pro-angiogenic and immunomodulatory mechanism.

Corneal Epithelial Removal with a Newly Designed Epithelial Brush

This study aimed to evaluate and compare the effectiveness of a newly developed epithelial removal brush with conventional methods in a rabbit model of corneal epithelial defects. The corneal epithelia of thirty-seven rabbits were removed by three different methods including blades (blade group), newly developed epithelial brushes (Ocu group), and conventional rotating brushes (Amo group). The defect area was measured with light microscopy immediately and at 4, 18, 24, and 50 hours after removal. Corneas were obtained immediately and at 24 and 50 hours and subjected to hematoxylin and eosin (H&E) and immunofluorescence staining using proliferating cell nuclear antigen (PCNA) and phosphorylated heat shock protein 27 (pHSP27) antibodies. The residual stromal surface was observed by scanning electron microscopy (SEM). In the Ocu group, epithelia were significantly recovered at 18, 24, and 50 hours compared with immediately after removal, and in the blade and Amo groups, epithelia were significantly recovered only at 50 hours after epithelial removal. The expression levels of PCNA and pHSP27 did not differ among three groups. There was significantly more inflammatory cell infiltration in the blade group than in the other groups. SEM showed a more regular and uniform residual stromal surface in the Ocu group than in the other groups. The newly developed epithelial brush showed better polishing ability and led to earlier significant epithelial recovery and a more regular and uniform stromal surface than conventional methods in this rabbit model of epithelial defects. Accumulation of clinical data is expected to expand the scope of application of new brushes for laser surface ablation.

P065 LONG TERM OUTCOMES AFTER LAPAROSCOPIC REPAIR OF VENTRAL HERNIAS LOCATED ON THE ABDOMINAL BORDERS

Aim To assess the long-term outcomes after laparoscopic repair (LR) of ventral hernias located on the abdominal borders. Material and methods Out of our prospectively collected LR database, all cases of ventral hernias were reviewed. Defects located near the abdominal borders were identified (M1, M5, L1 and L4 according to the EHS classification). All patients received intraperitoneal implantation of an e-PTFE mesh. The primary aim of this study was to assess long-term outcomes. Results Out of 175 LR, 105 (60%) had a M1 component, 61 (35%) an M5, 24 (14%) an L1 and 5 (3%) an L4. The median defect width was 9 cm (range 2.5 - 30), the median length 13 (range 2 - 30), with a median defect area of 92 cm2 (range 5 - 471). Two (1%) cases required conversion to open approach. After a median follow up of 55 months, there were 7 recurrences: 4/105 in M1 patients, 1/61 M5 patients, 1/24 L1 patients and 1/4 L4 patients. 41 patients (23%) experienced chronic seroma, while 24 (14%) had chronic pain. 6 patients (3%) required a reoperation with mesh removal. At univariate analysis, only previous hernia repair was associated with recurrence; COPD, hypertension and M5 defect were associated with seroma development; seroma development and chronic pain were mutually associated. Conclusions Laparoscopic repair for ventral hernias is safe and feasible, with good long term outcomes.

Three-dimensional Printed Polylactic Acid and Hydroxyapatite Composite Scaffold with Urine-derived Stem Cells Treatment for Bone Defects

BACKGROUND: Bone defects still pose various challenges in osteology. As one of the treatment options for bone defects, bone tissue engineering requires biomaterials with good biocompatibility and seed cells with good differentiation capacity. This study aimed to fabricate a 3D-printed polylactic acid and hydroxyapatite (PLA/HA) composite scaffold with urine-derived stem cells (USCs) to study its therapeutic effect in a model of skull defect in rats.METHODS: USCs, isolated and extracted from the urine of healthy adult males, were inoculated onto a 3D-printed PLA/HA composite scaffold and a PLA scaffold. Skull defect model rats were randomly divided into three groups (control, PLA, and PLA/HA). Twelve weeks after implanting scaffolds containing USCs into rats with a skull defect, the therapeutic efficacy was evaluated by real-time PCR, micro-CT, histology, and immunohistochemistry.RESULTS: The 3D-printed PLA/HA composite scaffold had good mechanical properties and porosity. The adhesion and proliferation of USCs on scaffolds also demonstrated excellent biocompatibility. PLA and PLA/HA containing USCs promoted bone regeneration in the defect area, supported by the general observation and CT images at 12 weeks after treatment, with coverage of 74.6%±1.9% and 96.7%±1.6%, respectively. Immunohistochemical staining showed a progressive process of new bone formation on PLA/HA scaffolds containing USCs at the defect site compared to that in PLA and control groups.CONCLUSION: The 3D-printed PLA/HA composite scaffold with USCs was successfully applied to the skull defect in rats. Under the linkage of the scaffold, the proliferation, differentiation, and osteogenesis expression of USCs were promoted near the bone defect area. These findings demonstrated broad application prospects of PLA/HA scaffolds with USCs in bone tissue engineering.

X-ray Image Recognition Method for Crimping Defects of Strain Clamp Based on OpenCV

The crimp quality of the tension clamp of the line affects the safety of the power grid. At present, the measurement of the quality of the tension clamp has certain limitations. An X-ray image detection method for strain clamp based on image processing technology is proposed. Firstly, the X-ray image of the strain clamp is taken and the image is preprocessed. Secondly, by selecting the defect part image of the typical defect sample, using some statements of OpenCV Python Library in Python to quickly identify and detect other X-ray pictures, and mark the defect part of other pictures. Finally, whether it is a defect is determined according to the cumulative value image of the gray value distribution of the marked defect area. Through the research in this paper, the rapid identification of the X-ray image of the crimping position of the tension clamp can be realized, which has important reference value for the engineering application of the crimping quality inspection of the tension clamp.

A Study on Railway Surface Defects Detection Based on Machine Vision

The detection of rail surface defects is an important tool to ensure the safe operation of rail transit. Due to the complex diversity of track surface defect features and the small size of the defect area, it is difficult to obtain satisfying detection results by traditional machine vision methods. The existing deep learning-based methods have the problems of large model sizes, excessive parameters, low accuracy and slow speed. Therefore, this paper proposes a new method based on an improved YOLOv4 (You Only Look Once, YOLO) for railway surface defect detection. In this method, MobileNetv3 is used as the backbone network of YOLOv4 to extract image features, and at the same time, deep separable convolution is applied on the PANet layer in YOLOv4, which realizes the lightweight network and real-time detection of the railway surface. The test results show that, compared with YOLOv4, the study can reduce the amount of the parameters by 78.04%, speed up the detection by 10.36 frames per second and decrease the model volume by 78%. Compared with other methods, the proposed method can achieve a higher detection accuracy, making it suitable for the fast and accurate detection of railway surface defects.