Defect Area Research Articles

Container Plasty in Advanced Painful Osteolytic Vertebral Metastases With Posterior Wall Defect

Study Design: Review of mesh-container plasty (MCP) in osteolytic vertebral metastases. Objective: This study aims to assess the efficacy and safety of MCP in treating advanced vertebral metastases with posterior wall defects. Background: Diagnosis of vertebral metastases typically relies on the patient’s tumor history, bone scans, or vertebral MRI. Surgical intervention often involves sampling vertebral body tissue for pathologic diagnosis. The revised Tokuhashi score is commonly used to predict survival time in patients with bone metastases. Outcome evaluation frequently employs the visual analog scale (VAS) and the Oswestry disability index (ODI) in assessing spinal surgery outcomes. Methods: A retrospective analysis included 111 patients treated between January 2014 and January 2018 in our hospital. Patients were categorized into 2 groups: MCP group (n=51) and PVP group (n=60). Grades based on the percentage of posterior wall defect area were established: grade I (≤25%), grade II (26% to 50%), grade III (51% to 75%), and grade IV (76% to 100%). Efficacy was assessed using VAS and ODI. Results: Both MCP and PVP groups exhibited significant pain relief and improved motor function. No significant differences were observed in VAS and ODI scores at any follow-up point (P>0.05). In the MCP group, bone cement leakage occurred in 13 cases, with a leakage rate of 25.49%. However, none of the patients experienced clinical or neurological symptoms. In the PVP group, bone cement leakage occurred in 50% of patients, with 6 patients developing neurological symptoms. Significant differences between the groups were observed in major complications related to bone cement leakage (P=0.03). Conclusion: MCP demonstrates efficacy in pain relief and safety in treating vertebral metastases with deficient posterior walls. It represents a promising option for spinal surgeons managing vertebral metastases with posterior wall deficiencies.

Photoactivated Hydrogel Therapeutic System with MXene-Based Nanoarchitectonics Potentiates Endogenous Bone Repair Through Reshaping the Osteo-Vascularization Network.

The repair and reconstruction of large-scale bone defects face enormous challenges because of the failure to reconstruct the osteo-vascularization network. Herein, a near-infrared (NIR) light-responsive hydrogel system is reported to achieve programmed tissue repair and regeneration through the synergetic effects of on-demand drug delivery and mild heat stimulation. The spatiotemporal hydrogel system (HG/MPa) composed of polydopamine-coated Ti3C2Tx MXene (MP) nanosheets decorated with acidic fibroblast growth factor (aFGF, a potent angiogenic drug) and hydroxypropyl chitosan/gelatin (HG) hydrogel is developed to orchestrate the reconstruction of the osteo-vascularization network and boost bone regeneration. Upon exposure to NIR light irradiation, the engineered HG/MPa hydrogel can achieve the initial complete release of aFGF to induce rapid angiogenesis and provide sufficient blood supply, maximizing its biofunction in the defect area. This integrated hydrogel system demonstrated good therapeutic efficacy in promoting cell adhesion, proliferation, migration, angiogenesis, and osteogenic differentiation through periodic NIR irradiation. In vivo, animal experiments further revealed that the spatiotemporalized hydrogel platform synergized with mild photothermal treatment significantly accelerated critical-sized bone defect healing by increasing the osteo-vascularization network density, recruiting endogenous stem cells, and facilitating the production of osteogenesis/angiogenesis-related factors. Overall, smart-responsive hydrogel couldenhance the reconstruction of the osteo-vascularization network in bone regeneration.

Phrenoplasty Techniques for the Reconstruction of Basal Chest Wall Defects

Background: Primary and secondary tumors of the abdominal lower third of the bony thorax are relatively rare. Therefore, indications and techniques for chest wall reconstructions in this area are not well defined. Methods: The techniques for reconstructing basal chest wall defects using the diaphragm are described. Indications for phrenoplasty are limited to reconstruction after full-thickness resection of at least two of the last four ribs in the midaxillary line. The diaphragm can be used for reconstructive purposes both if it is intact and if it is partially involved in the resection of the chest wall. Results: At our institution, the abovementioned reconstructive technique was successfully performed in five patients with an uneventful post-operative course. Conclusions: The main advantages of these methods are the use of promptly available, high-quality autologous tissue and the exclusion of the pleural space from the defect area, thus transforming a thoracic defect into an abdominal one. The disadvantage is a variable reduction in the volume of the hemithorax. These techniques could be compared with other reconstruction techniques using pre-/post-operative respiratory functional tests.

A cadaveric study of induced isolated orbital floor fractures and implications for surgical decision-making: comparison of two preoperative imaging modalities

Computed tomography (CT) is the gold standard for the diagnosis of isolated orbital floor fractures, while cone beam computed tomography (CBCT) is an alternative. The aim of this study was to compare the diagnostic accuracy of CT and CBCT for isolated orbital floor fractures. Forty-eight isolated orbital floor fractures were systematically induced in cadaver orbits. CBCT and CT scans of each cadaver head were performed and the image data imported into ProPlan CMF for analysis. The orbital floor area (OFA), orbital defect area (ODA), and peri-orbital tissue herniation were evaluated. Surgical decision-making differed significantly according to the imaging modality (P = 0.031). The odds of decision discrepancy between CBCT and CT were higher with increasing ODA/OFA ratios, when adjusted for peri-orbital tissue herniation and fracture localization (P = 0.026). An ODA/OFA ratio cut-off value of >36.25% had a sensitivity of 100% and specificity of 71% (area under the curve 0.83, P = 0.011) for predicting discrepancies between CBCT and CT in surgical decision-making. In this cadaveric study, CT and CBCT were diagnostically equivalent for isolated orbital floor fractures with an ODA/OFA ratio ≤36.25%. However, fractures exceeding this threshold may be better evaluated by CT to avoid discrepancies in surgical decision-making.

Comparative histomorphological assessment of the osteoinductive capacity of a nanofibrillated cellulose-based composite and autologous blood clot.

The present study aimed to evaluate and compare the effect of nanofibrillated cellulose (NFC)-based composite with dicalcium phosphate dihydrate and an autologous blood clot (ABC) on the formation of new bone tissue in vivo by histological and histomorphometric assessment. A total of 72 rats with created femoral defects (2 mm) were used. The rats were divided into three groups: (1) with filling of the defect with an ABC, (2) NFC-1-with filling of both the cortical plate and intramedullary space in the defect area, and (3) NFC-2-with filling of only the intramedullary space in the defect area. Histological and histomorphometric analysis was performed to assess the healing of the bone defect after 14, 30 and 60 days. Complete closure of the cortical plate defect was detected in the NFC-2 group on Day 30 (p < 0.0001). Moreover, in both NFC groups on the 30th and 60th days, ongoing osteogenesis was observed, characterized by a large volume of newly formed circular pattern bone tissue in the intramedullary space. This study demonstrated that the NFC-based composite, which is located below the level of the cortical plate, tamponing only the intramedullary space (NFC-2), improves bone tissue repair at the site of a bone defect of the cortical plate and has the potential of prolonged osteoinductivity. Not applicable.

Comparison of the Effects of Microfracture, Soft Callus Implantation, and Matrix-Supported Chondrocyte Implantation in an Experimental Osteochondral Defect Model in Rats

Background: The treatment of cartilage defects remains challenging due to the avascular nature of cartilage. Aim: This study investigates the therapeutic effect of soft callus in osteochondral defects and explores the ability of multipotent and pluripotent cells within the callus to form fibrous or hyaline cartilage in the defective area. Methods: Twenty-one rats were divided into three equal groups: Group 1 received only microfracture (MF), group 2 received microfracture with autologous chondrocyte implantation (MF+ACI), and group 3 received microfracture with soft callus implantation (MF+SCI). All rats underwent diaphyseal fracture in their left tibias, which was stabilized with a Kirshner wire. One week later, osteochondral defects were created in the right knees of all rats. For group 1, microfracture alone was applied to initiate healing in the defects. In group 2, heterologous chondrocytes, previously harvested from the lateral condyle of a rat’s left femur and cultivated in a laboratory environment, were implanted into the microfracture site. In group 3, soft callus tissue obtained from the left tibial fracture was compressed and implanted into the defective area. All groups were sacrificed at the 6th week, and the healing status of the osteochondral defect areas was histopathologically evaluated. Results: Macroscopic examination at the end of the study revealed comparable ICRS-1 scores for MF+ACI (group 2) (11.28 ± 1.25) and MF+SCI (group 3) (11.14 ± 0.37), while MF alone (group 1) (4.28 ± 1.25) showed significantly lower results. Microscopic examination yielded similar outcomes. Regarding histological scores, ICRS-2 scores for MF (group 1) (35.30 ± 1.13), MF+ACI (group 2) (47.09 ± 1.63), and MF+SCI (group 3) (43.97 ± 1.49) were statistically significantly lower. Conclusion: Defects treated with soft callus implantation demonstrated comparable outcomes to the widely used and gold-standard autologous chondrocyte implantation. When compared to microfracture alone, better macroscopic and microscopic results were achieved with soft callus implantation.

Does defect size matter in abdominal wall reconstruction with successful fascial closure?

BackgroundConflicting literature suggests that larger defects in abdominal wall reconstruction both increase the risk of recurrence and have no impact on recurrence. In our prior work, hernias with defect areas ≥100 cm2 were associated with increased discomfort, operative time, and length of stay but not recurrence or reoperation. Our goal was to determine if defect size, even in giant hernias, would impact recurrence after mesh repair with complete fascial closure. MethodsA prospectively maintained hernia database was reviewed for clean, abdominal wall reconstruction with fascial closure and synthetic mesh. Patients were grouped and compared by defect area: moderate hernias <200 cm2 (LT200) and giant hernias ≥200 cm2 (GT200). ResultsOf 984 patients, 607 LT200 (average area: 92.8 ± 60.8 cm2) were compared with 377 GT200 (average area: 363.2 ± 196.7 cm2). LT200 and GT200 had similar mean age, body mass index, and smoking rate, but GT200 had higher rates of diabetes (22.1% vs 27.9%; P = .040), recurrent hernias (52.7% vs 63.4%; P = .001), preoperative Botox (0.7% vs 8.8%; P < .001), component separation (23.4% vs 59.9%; P < .001), panniculectomy (8.7% vs 15.4%; P = .001), and negative-pressure incisional vacuum placement (5.9% vs 13.5%; P < .001). GT200 had increased mesh size (753.5 ± 367.1 vs 1168.2 ± 412.0 cm2; P < .001), operative time (147.8 ± 55.7 vs 205.3 ± 59.9 minutes; P < .001), and length of stay (5.1 ± 3.2 vs 6.9 ± 4.4 days; P < .001). GT200 had more wound complications (24.7% vs 36.1%; P < .001) and readmissions (9.1% vs 15.1%; P = .004) but similar recurrence rates (3.0% vs 3.7%; P = .520) over the mean follow-up of 30.1 ± 38.9 and 23.0 ± 33.6 months for LT200 and GT200, respectively. On multivariable regression, previous abdominal wall reconstruction, lightweight mesh, and wound complications independently predicted recurrence; component separation was protective, but defect size was not predictive of recurrence. ConclusionGT200 required more complex measures to achieve fascial closure and resulted in increased length of stay, wound complications, and readmissions; however, GT200 had the same recurrence rate as smaller defects when fascial closure was achieved.

The Papilla Base CTG: A Novel Approach for Interdental Soft Tissue Reconstruction.

Impairment or loss of interdental papilla is a common issue in patients with periodontal disease, leading to phonetic, functional, and aesthetic concerns. Numerous techniques have been explored to reconstruct and regenerate interdental papillae, but consistent success remains challenging. This article presents a novel surgical approach that applies the principles of the Connective Tissue Graft (CTG) wall technique to enhance papilla volume when interdental clinical attachment loss is present in the aesthetic zone. The case of a 35-year-old woman with an RT3 recession defect associated with loss of interdental hard and soft tissues is discussed. The patient underwent a procedure involving palatal incisions, application of amelogenins, and a trapezoidal shape CTG fixed at the base of the papilla under a coronally advanced flap. This approach aimed to stabilize the blood clot and prevent soft tissue collapse into the defect area, enhancing the position and volume of the interdental papilla. Results at 6- and 12-months follow-up indicated significant improvement in papilla appearance and complete root coverage. This case suggests that the modified CTG wall technique can effectively treat buccal and interdental gingival recessions associated with horizontal or infrabony defects. Further clinical trials are necessary to confirm these findings and establish the most effective approach for interdental papilla reconstruction.

Nonlinear characteristics in the cylindrical roller bearing with raceway defects

Cylindrical roller bearings (CRBs) are subjected to significant cyclic stress under extreme operating conditions. This leads to the formation of localized wave defects on the raceway surface, such as burn. Thus, a new mathematical model is proposed to consider the local wave defects on the raceway caused by burns in this paper. Further, a dynamic model of CRB incorporating raceway defects is developed based on the contact relationships between components, and the proposed model is verified by measured acceleration responses. The effects of local wave defects on the nonlinear vibration characteristics of the bearings are studied and the results show that an increase in the number of defect waves reduces the additional displacement of rollers passing through the defect area, obscuring signal characteristics induced by the defect. Moreover, the presence of the defect influences the nonlinear interaction between the roller and raceway, which subsequently affects the cage whirling motion. This study of bearing dynamic behavior in this paper can contribute to the condition monitoring of bearings.

Experimental validation of coronary stenosis severity and development of ischemic myocardium

The current study aimed to evaluate the causal association between hemodynamically significant stenosis and the occurrence of ischemic myocardium using an experimental animal model of coronary artery stenosis. In Yorkshire swine (n = 10), coronary stenosis in the left anterior descending artery was induced using a customized vascular occluder to create varying degrees of occlusion severity (40%-99%). Serial changes in coronary pressure and flow velocity were measured in the left anterior descending artery before and after the implantation of the vascular occluder. At 1 month, 13N-ammonia positron emission tomography (PET) was performed, followed by the collection of isolated hearts for 2,3,5-Triphenyltetrazolium chloride (TTC) staining to quantify the percent area of necrotic myocardium. Three animals in the control group were evaluated using the same protocols, but without the implantation of a vascular occluder Results: The median diameter stenosis after vascular occluder implantation was 61.3% (Q1-Q3: 55.9%-72.3%). Significant differences were observed in hyperemic stenosis resistance, fractional flow reserve (FFR), stress perfusion defect and reversibility in PET, as well as in necrotic myocardium in TTC staining based on stenosis severity (control group: < 50%, 50%-70%, 70%-90%, and > 90%) (all P < .010). Animals with FFR < 0.75 at 1 month exhibited a significantly higher area of stress perfusion defect (30.7 ± 3.1% vs 6.0 ± 4.2%, P < .001), reversibility in PET (11.0 ± 4.0% vs 0.0 ± 0.0%, P = .006), and necrotic myocardium in TTC staining (15.8 ± 6.4% vs 0.0 ± 0.0%, P < .001) than those with FFR ≥ 0.75. In a porcine model, the induction of hemodynamically significant stenosis with FFR < 0.75 was associated with the development of stress perfusion defects and reversibility in PET, as well as necrotic myocardium identified by pathology.

Topical Application of 0.05% Cyclosporine for the Treatment of Neurotrophic Keratopathy Secondary to Herpes Simplex Keratitis

The purpose of this study was to assess the effectiveness and tolerability of 0.05% cyclosporine A (CsA) eye drops for neurotrophic keratopathy (NK) secondary to herpes simplex keratitis (HSK). Fifteen patients (15 eyes) with prior HSK and secondary NK, classified as stage 2 or 3 on the basis of the Mackie classification, were enrolled. All patients received a combined treatment regimen of 0.05% CsA eye drops (1 drop 4 times daily), a silicone hydrogel bandage contact lens, and 0.15% ganciclovir ophthalmic gel (1 drop 3 times daily). For patients achieving corneal healing, CsA was continued at a reduced dosage of twice daily for an additional 2 months and other treatments were discontinued. Follow-ups were scheduled at weeks 1, 2, 3, and 4 and at months 2 and 3 after treatment initiation, followed by a 3-month follow-up period. Key outcomes, including best-corrected visual acuity, Schirmer I test, and corneal sensitivity, were assessed at each visit before and after treatment. Significant reductions were observed in the area of corneal defects, expressed as proportion of total corneal area, throughout follow-up period. Complete corneal healing was achieved by 13.3% of patients by week 2, 60.0% by week 3, 86.7% by week 4, and 100.0% by week 8, with the mean (SD) time to healing being 3.8 (1.8) weeks (range, 2-8 weeks). Additionally, significant improvements were noted in diseased eyes for best-corrected visual acuity, tear secretion (Schirmer I test values), and corneal sensitivity after treatment. CsA eye drops, with bandage lenses and ganciclovir, effectively resolve NK from HSK, without adverse effects. This combination therapy shows promise for future clinical use and research. Our study is a retrospective observational study because it involves the analysis of previously collected data, so the study was not registered prior to its commencement. However, if it is necessary for publication, we are willing to proceed with retrospective registration.

High temperature induced abundant closed nanopores for hard carbon as high-performance sodium-ion batteries anodes

Hard carbon (HC) stands out as the preeminent anode material for sodium-ion batteries (SIBs) which are deployed in expansive energy storage infrastructures. Herein, the large enough graphene nanosheets interlayer and abundant nanopores with a diameter of ∼2.1 nm induced by adjusting the pyrolysis temperature in the thermosetting phenolic resin-derived hard carbon matrix to augment the performance of the sodium ion storage. The presence of sufficiently large carbon interlayers has been proven to provide active sites for reversible adsorption, enabling effective storage of sodium ions in the high-voltage slope region, while also promoting rapid Na+ transport. Meanwhile, forming abundant closed nanopores with larger sizes helps sodium ion storage in the low-voltage plateau region. In the optimized samples, the formation of sufficient long graphene nanosheets with a perfect crystal lattice, which further shrinks to form enclosed nanopores, effectively reduces defective sites and specific surface area. Additionally, the appropriate content of C-O and C=O functional groups contributes to an exceptional initial Coulombic efficiency (ICE) of up to 93%. Simultaneously, the optimized sample HC-1500 contributes to a remarkable plateau capacity of 294 mAh g-1 during the charging process (high reversible capacity of 403 mAh g-1 at 0.1 C). Moreover, based on the microstructure evolution and Na storage behavior of hard carbon, an “adsorption (27%) – filling (73%)” sodium storage mechanism that the sodium storage as a quasi-metallic sodium state is demonstrated. Consequently, this study will offer valuable insights for the development of hard carbon anodes tailored for high-energy practical SIBs, while also advancing the understanding of sodium storage mechanisms.

Optimization of thermal shock response spectrum as infrared thermography post-processing methodology using Latin hypercube sampling and analytical thermal N-layer model

In this work, we continue to develop and investigate the Thermal Shock Response Spectrum (TSRS) method as an alternative data processing method for infrared thermography (IRT). We focus on improving the current TSRS algorithm and present an optimization methodology for finding the optimal thermal Q-factor and characteristic frequency pair, which is based on the widely applied random sampling method. We show the qualitative relationship between the determined optimal characteristic frequency and the corresponding maximum difference in diffusion length between reference and defective models, as calculated by selecting a specific one-dimensional thermal N-layer model The investigations were performed on an inhomogeneous plate made of carbon fiber reinforced polymer (CFRP) with artificial square defects at different depths. Furthermore, two different heat sources were used: a xenon flash lamp and a laser. These sources are not only distinct by their underlying physics but also generate inherently different pulse shapes. To quantitatively estimate the contrast between defect and non-defect areas, and to compare these results with commonly used infrared thermography (IRT) data post-processing methods such as Pulse Phase Thermography (PPT) and Thermographic Signal Reconstruction (TSR), the Tanimoto criterion (TC) and signal-to-noise ratio (SNR) were used.

Simultaneous low-frequency vibration isolation and energy harvesting via attachable metamaterials

In this study, we achieved energy localization and amplification of flexural vibrations by utilizing the defect mode of plate-attachable locally resonant metamaterials, thereby realizing compact and low-frequency vibration energy suppression and energy harvesting with enhanced output performance. We designed a cantilever-based metamaterial unit cell to induce local resonance inside a periodic supercell structure and form a bandgap within the targeted low-frequency range of 300–450 Hz. Subsequently, a defect area was created by removing some unit cells to break the periodicity inside the metamaterial, which led to the isolation and localization of the vibration energy. This localized vibration energy was simultaneously converted into electrical energy by a piezoelectric energy harvester coupled with a metamaterial inside the defect area. Consequently, a substantially enhanced energy harvesting output power was achieved at 360 Hz, which was 43-times higher than that of a bare plate without metamaterials. The proposed local resonant metamaterial offers a useful and multifunctional platform with the capability of vibration energy isolation and harvesting, while exhibiting easy handling via attachable designs that can be tailored in the low-frequency regime.

Reconstructive surgical therapy of peri-implant defects with ribose cross-linked collagen matrix and crosslinked hyaluronic acid – a prospective case series

ObjectiveTo investigate the efficacy of ribose-crosslinked collagen (RCLC) matrices functionalized by crosslinked hyaluronic acid (xHya) for reconstructive treatment of class I and III (b-c) peri-implantitis lesions in a transmucosal healing mode.Materials and methodsThirteen patients presenting with 15 implants were included in this prospective case series. Upon flap reflection, the implants were thoroughly decontaminated employing glycine powder air polishing and adjunctive sodium hypochlorite. For defect augmentation, xHyA was administered to the bony defect walls, exposed implant surfaces, and the RCLC matrix before defect grafting. The full-thickness flap was readapted and sutured around the implant neck for transmucosal healing. Baseline and respective values at the 12 months post-op evaluation were recorded for the clinical parameters peri-implant probing depth (PPD), buccal soft tissue dehiscence (BSTD) and bleeding on probing (BoP). Furthermore, two independent investigators analyzed radiographic changes in the defect area. The mean changes for all variables were analyzed with a paired t-test.ResultsThe initial mean PPD was 7.2 ± 1.9 mm, and BoP was present in 63% of sites. After 12 months, PPD at the latest visit was 3.2 ± 0.66 mm, which amounted to a respective 3.9 ± 1.85 mm reduction, while the BoP frequency dropped to 10% at all sites. Radiographic bone fill was accomplished for 62.8% of the former defect area, accompanied by a mean MBL gain of 1.02 mm around the treated implants (all p < 0.001).ConclusionsWithin the limits of this case series, we conclude that the proposed treatment sequence substantially improved peri-implant defects and offered a simplified but predictive technique.Clinical relevanceReconstructive treatment approaches for peri-implantitis are effective but remain non-superior to open flap debridement. Further research on novel biomaterial combinations that may improve reconstructive treatment outcomes are warranted. Ribose-crosslinked collagen matrices biofunctionalized by hyaluronic acid used in this study yield improved clinical and radiographic peri-implant conditions after 12 months.Graphical

Comparative Evaluation of Topical Monotherapy (Natamycin or Natasol) and Combination Therapy (Natamycin and Voriconazole) in Mild-Moderate Fungal Keratitis.

To compare the efficacy of monotherapy (natamycin 5% or Natasol 1%) versus combination therapy (natamycin 5% and voriconazole 1%) in the treatment of mild-moderate fungal keratitis. In a prospective, comparative, interventional study, 60 eyes of 60 patients with mild-moderate fungal keratitis were included and randomized in 3 groups based on the topical antifungal therapy received: group 1, natamycin 5%; group 2, Natasol 1% (1% w/v aqueous natamycin); and group 3, combination of natamycin 5% and voriconazole 1%. 51 of 60 cases (85%) resolved with medical management only. Trauma was the major predisposing factor. Aspergillus species was the most common organism isolated. There was comparable decrease in the corneal infiltrate area from 16.92 ± 7.24, 15.12 ± 7.15, and 20.39 ± 4.81 mm2 in groups 1, 2, and 3, respectively (P > 0.05) at all follow-ups [days 3, 7, 30, 60, and 90]. There was a trend of early reepithelization in the Natasol group. The area of epithelial defect was comparable at baseline among all 3 groups (P = 0.24) and was statistically smaller in the Natasol group at 1-month follow-up (P = 0.01). The duration to complete epithelization was shortest in the Natasol group (37 ± 10 days; P = 0.02) compared with group 1 (45 ± 12 days) and group 3 (49 ± 12 days). The corrected distance visual acuity improved significantly and comparably in all groups (P = 0.4). Topical Natasol 1% tends to shorten the time to complete epithelization in cases of mild-moderate fungal keratitis compared with topical natamycin 5% and combination therapy of natamycin 5% and voriconazole 1%.

Non-destructive testing for thickness measurement of the adhesive layer and defect detection in ceramic-metal bonded structures using THz waves

Ceramics, owing to their superior thermal barrier properties, are employed by bonding them to primary structures exposed to elevated temperatures, such as the external components of aircraft and spacecraft. However, when these bonded structures are subjected to thermal impact resulting from high-temperature environments or rapid temperature variations, issues such as debonding, crack formation, and degradation may ensue. These issues can significantly undermine the reliability of the structures, necessitating nondestructive testing (NDT) to monitor the condition of the adhesive layer before and after thermal impact. In this article, we evaluated the integrity of adhesive structures before and after thermal impact using Terahertz (THz) waves, which offer exceptional penetration and resolution for NDT of nonmetallic materials without causing damage to the structure. To achieve this, ceramic-metal bonded structures were mounted on a robotic arm, and scanning was performed over a 70 mm area at 1 mm intervals and 0.5° increments. The peak-to-peak time of the THz signal through the adhesive layer was calculated to determine the thickness distribution. Based on experimental results, the average thickness of the ceramic layer before thermal shock was measured at 9.48 mm (standard deviation: 0.03) and the average thickness of the adhesive layer was 0.234 mm (standard deviation: 0.03). Additionally, four suspected defect areas within the adhesive layer were identified. After thermal shock, the ceramic layer’s thickness decreased by an average of 0.02 mm (0.17%), resulting in an average thickness of 9.46 mm, and the adhesive layer’s thickness decreased by an average of 0.002 mm (0.99%), resulting in an average thickness of 0.232 mm. The four suspected defect areas were confirmed to be in the same locations before thermal impact. To validate the NDT method using THz wave, the ceramic-metal bonded structure was cut to identify debonding defects in the suspected areas. The difference between the thickness distribution obtained using the THz wave-based NDT and that measured using optical microscopy after cutting was 4.4%, confirming the accuracy of the THz wave-based method for defect detection and thickness measurement.

Promising clinical effect of arthroscopic autologous iliac bone grafting with suture anchor binding fixation for recurrent anterior shoulder instability.

To evaluate the clinical efficacy of arthroscopic autologous iliac bone grafting with suture anchor binding fixation combined with a Bankart repair for recurrent anterior shoulder dislocation with a significant anterior glenoid defect. Patients with recurrent anterior shoulder dislocation with an anterior glenoid defect area greater than 20% admitted to our department from March 2019 to March 2022 were prospectively enrolled. Arthroscopic autologous iliac bone grafting with suture anchor binding fixation combined with a Bankart repair was performed. Computed tomography (CT) images were captured preoperatively, immediately after surgery, and at 3, 6, and 12 months postoperatively to evaluate the glenoid defect area, graft area, and graft healing. Shoulder function was assessed using the Instability Severity Index, Oxford Shoulder Instability, and Rowe scores recorded preoperatively and at the final follow-up. The shoulder range of motion, shoulder stability test, surgery-related complications, subluxation/dislocation, and revision surgery were also evaluated. A total of 32 patients were included in the study, with an average follow-up time of 18.3 ± 6.3 months, when the graft healing rate was shown to be 100%. The area ratio of the graft to the glenoid was 37.6% ± 10.5% (range, 23.5%-44.1%) determined by an enface-view three-dimensional CT performed immediately after surgery, and 29.2 ± 8.2% (range, 19.6%-38.7%) at 12 months postoperatively. At the final follow-up, the glenoid defect had improved from 28.7 ± 6.4% (range, 20.5%-40.6%) before surgery to -10.2 ± 4.7% (range, -13.8% to 6.1%). The preoperative Rowe and Oxford scores were 56.4 ± 8.5 and 34.7 ± 7.1 respectively, which improved to 94.3 ± 6.7 and 15.3 ± 3.2 at the final follow-up (p < .001). All patients had no limited shoulder joint activity, no re-dislocation or revision surgery, and no neurovascular injury. For recurrent anterior shoulder dislocation with an anterior glenoid defect area greater than 20%, arthroscopic autologous iliac bone grafting with suture anchor fixation combined with a Bankart repair produced a promising clinical effect. A significant shoulder function score was achieved, as was a 100% bone healing rate and ideal glenoid reconstruction without major complications. Thus, this technique may be considered an alternative to the classic Latarjet approach to treat recurrent anterior shoulder dislocation with an anterior glenoid defect area greater than 20%. IV.

To PE or Not to PE: Perfusion SPECT/CT Avoids Overdiagnosis.

A 41-year-old woman with metastatic breast cancer presented with dyspnea, hypoxia, and elevated d -dimer. Perfusion planar imaging followed by SPECT/CT of the chest was performed due to the patient's iodinated contrast allergy. Planar images showed multiple pleural-based wedge-shaped defects concerning for bilateral pulmonary embolism (PE). Perfusion SPECT/CT of the chest confirmed multiple areas of perfusion defects but was considered negative for PE and attributed the perfusion defects to the compressing of pulmonary vasculature from metastatic lymph nodes and pulmonary masses. Given the high pretest probability of PE, a CT pulmonary angiogram was performed after premedication for contrast allergy confirming absence of PE.

Crack suppression in directed energy deposition of molybdenum

Additive manufacturing (AM) is a valuable tool for the fabrication and repair of refractory parts such as molybdenum alloys. Cracking is a common defect encountered during AM processing of refractory parts, that is generally associated with the segregation of light elements to grain boundaries which affect grain boundary cohesion and, ultimately, affect the final performance of the part. Similarly, because of the high melting points of refractory metals, lack-of-fusion defects are also common. The effect of build substrate and small alloying additions on suppression of defects during multilayer builds was investigated using directed energy deposition (DED) printing. Identical sample matrices were printed on three different build substrates: molybdenum (Mo), commercially pure titanium (Cp-Ti), and 316 stainless steel (316). Twenty-six usable samples were produced. Samples were cross sectioned, polished, and were characterized for total cross-section defect area. Additionally, samples from each substrate material were analyzed for grain boundary oxygen content. The strongest defect suppression, producing crack free material, was observed in samples printed on a Cp-Ti build substrate with a ten atomic percent addition of titanium in the molybdenum powder feed. The part quality was enhanced due to three factors: 1) the moderation of thermal diffusivity through a change in build plate material, 2) the suppression of light element segregation via increased solubility through titanium addition, and 3) a lack of brittle phase formation due to metallurgical compatibility of the build material with the build substrate. Analysis of defect area versus dimensionless number, π1, shows that increasing π1 reduced defects throughout the part.