A novel physics-informed framework for reconstruction of structural defects

The ultrasonic guided wave technology plays a significant role in the field of non-destructive testing as it employs acoustic waves with the advantages of high propagation efficiency and low energy consumption during the inspect process.However,the theoretical solutions to guided wave scattering problems with assumptions such as the Born approximation have led to the poor quality of the reconstructed results.Besides,the scattering signals collected from industry sectors are often noised and nonstationary.To address these issues,a novel physics-informed framework(PIF)for the quantitative reconstruction of defects by means of the integration of the data-driven method with the guided wave scattering analysis is proposed in this paper.Based on the geometrical information of defects and initial results obtained by the PIF-based analysis of defect reconstructions,a deep-learning neural network model is built to reveal the physical relationship between the defects and the noisy detection signals.This learning model is then adopted to assess and characterize the defect profiles in structures,improve the accuracy of the analytical model,and eliminate the impact of the noise pollution in the process of inspection.To demonstrate the advantages of the developed PIF for the complex defect reconstructions with the capability of denoising,several numerical examples are carried out.The results show that the PIF has greater accuracy for the reconstruction of defects in the structures than the analytical method,and provides a valuable insight into the development of artificial intelligence(AI)-assisted inspection systems with high accuracy and efficiency in the fields of structural integrity and condition monitoring.

Local random flaps for cervical circumferential defect or tracheoesophageal fistula reconstruction after failed gastric pull-up: Two case reports

BACKGROUND Total pharyngo-laryngo-esophagectomy with a reconstruction of gastric pull-up is the most common treatment method for patients with multiple primary upper digestive tract carcinomas,such as hypopharyngeal carcinoma with thoracic esophageal carcinoma.However,neck circumferential defect and tracheoesophageal fistula after gastric necrosis are still challenging problems for surgeons and patients.CASE SUMMARY This case report presents 2 patients who underwent reconstructive surgeries using 4 local random flaps with a split thickness skin graft in the first case,and 6 local random flaps in the second case to close the circumferential defect and tracheoesophageal fistula after failed gastric pull-up.Both patients achieved good swallowing function and could take solid diet without dysphagia postoperatively.CONCLUSION For selected patients,local random flaps(with a split thickness skin graft)can be a simple and reliable solution for reconstructing tracheoesophageal fistula or cervical circumferential defect after gastric necrosis,especially when the necrosis extends below the thoracic inlet.

Experimental Study of Porous Beta-tricalcium Phosphate and Bone Morphogenetic Protein/porous Beta-tricalcium Phosphate Complex in Rabbit Mandibular Reconstruction

We investigated the osteogenic characteristic and biodegradation behavior of porous beta-tricalcitum phosphate （ β- TCP ） and bone morphogenetic protein/beta-tricalcium phosphate （ BMP/ β- TCP ） complex in mandibular reconstruction and evaluated the advantages of BMP / β- TCP complex in repairing bone defects. Bone defects created in the lower margin of bilateral mandible bodies in 12 rabbits were repaired with β- TCP （ control group ） and BMP/ β- TCP complex （ experimental group ） respectively. The rabbits were euthanized after 2, 4, 8 and 12 weeks and examined by macroscopy, radiography, histology, histomorphometry and image analysis. 2 weeks after surgery, ossftcation of newly-generated tissue in BMP/ β- TCP complex group appeared and after 12 weeks, massive new bone and ossification maturation were seen. However, in β- TCP group without BMP , ossification was not found until 12 weeks after operation. Image analysis showed that bone regeneration rate of BMP/ β- TCP was 30%-40% higher and the degradation rate was 20%- 30% higher than that of β- TCP. Therefore, as a reconstructive material for bone defects, BMP/ β-TCP complex is superior to β-TCP and can be used in oral and maxillofacial surgery.

Reconstruction of tracheal defect using the contralateral musculo-periosteum flap of the sternocleidomastoideus with clavicular periosteum

To reconstruct tracheal defect after tumor excision,we used the contralateral musculo-periosteum flap of the sternocleidomastoideus with clavicular periosteum.Methods The contralateral musculo-periosteum flap of the sternocleidomastoideus with clavicular periosteum was used to reconstruct the tracheal defect when the blood supply to the ipsilateral sternocleidomastoideus was destroyed because of lymphonode clearing or radiotherapy.The pedicle of the musculo-periosteum flap was dissected adequately and the blood supply was protected carefully.Results All flaps survived with epithelization and osteogenesis.The endotracheal tubes were pulled out safely without trachea stenosis in all the patients.Conclusion The contralateral musculo-periosteum flap of the sternocleidomastoideus with clavicular periosteum could reconstruct the tracheal defect when the ipsilateral blood supply was damaged.This method extends the application of the musculo-periosteum flap.3 refs,4 figs.

Design,characterisation,and clinical evaluation of a novel porous Ti-6Al-4V hemipelvic prosthesis based on Voronoi diagram

Three-dimensional printed Ti-6Al-4V hemipelvic prosthesis has become a current popular method for pelvic defect reconstruction.This paper presents a novel biomimetic hemipelvic prosthesis design that utilises patient-specific anatomical data in conjunction with the Voronoi diagram algorithm.Unlike traditional design methods that rely on fixed,homogeneous unit cell,the Voronoi diagram enables to create imitation of trabecular structure(ITS).The proposed approach was conducted for six patients.The entire contour of the customised prosthesis matched well with the residual bone.The porosity and pore size of the ITS were evaluated.The distribution of the pore size ranged from 500 to 1400μm.Porosity calculations indicated the average porosity was 63.13±0.30%.Cubic ITS samples were fabricated for micrograph and mechanical analysis.Scanning electron microscopy images of the ITS samples exhibited rough surface morphology without obvious defects.The Young’s modulus and compressive strength were 1.68±0.05 GPa and 174±8 MPa,respectively.Post-operative X-rays confirmed proper matching of the customised prostheses with the bone defect.Tomosynthesis-Shimadzu metal artifact reduction technology images indicated close contact between the implant and host bone,alongside favourable bone density and absence of resorption or osteolysis around the implant.At the last follow-up,the average Musculoskeletal Tumour Society score was 23.2(range,21-26).By leveraging additive manufacturing and Voronoi diagram algorithm,customised implants tailored to individual patient anatomy can be fabricated,offering wide distribution of the pore size,reasonable mechanical properties,favourable osseointegration,and satisfactory function.

Functional thenar eminence myocutaneous flap for reconstruction of thumb volar defect

This case report describes the use of a Functional Thenar Eminence myocutaneous flap for reconstruction of volar defect of distal right thumb of a 25-year-old male who sustained a twisting injury while working. Part of bone and tendon were exposed and the tip of the distal phalanx was crushed, with bony defect.

Advances in osseointegration of biomimetic mineralized collagen and inorganic metal elements of natural bone for bone repair

At this stage,bone defects caused by trauma,infection,tumor,or congenital diseases are generally filled with autologous bone or allogeneic bone transplantation,but this treatment method has limited sources,potential disease transmission and other problems.Ideal bone-graft materials remain continuously explored,and bone defect reconstruction remains a significant challenge.Mineralized collagen prepared by bionic mineralization combining organic polymer collagen with inorganic mineral calcium phosphate can effectively imitate the composition and hierarchical structure of natural bone and has good application value in bone repair materials.Magnesium,strontium,zinc and other inorganic components not only can activate relevant signaling pathways to induce differentiation of osteogenic precursor cells but also stimulate other core biological processes of bone tissue growth and play an important role in natural bone growth,and bone repair and reconstruction.This study reviewed the advances in hydroxyapatite/collagen composite scaffolds and osseointegration with natural bone inorganic components,such as magnesium,strontium and zinc.