Patch Material Research Articles

In-situ acoustic emission based technique for damage detection and identification and failure mode prediction in scarf repaired composite structures

One of the great challenges facing adhesively bonded repair procedures in the industry is the absence of a reliable structural health monitoring technique to ensure that the repaired region is intact during service. To this end, this paper proposes a novel in-situ acoustic emission-based methodology to detect and identify damages as well as to predict failure modes at early stages. In this essence, two tapered-scarf repaired plates are produced with different patch materials. The first patch consists of neat carbon fiber prepregs whereas in the second thermally exfoliated graphene oxide integrated carbon fiber prepregs are utilized. Testing the constituents of the repair system individually while monitoring their acoustic activity makes it possible to separate each damage type precisely. Hence, when the specimens of the repaired panel are tested, very detailed information is revealed regarding the current structural status of the specimen and probable failure scenarios. The effectiveness and robustness of the proposed methodology in detecting and identifying damages of varying severity in addition to predicting the failure scenario are verified in the composite panels repaired with pristine and graphene integrated patches.

Effect of repair patch nature on J-integral reduction in notched plates

PurposeThe purpose of this research is to evaluate the effectiveness of different repair patch materials in reducing the stresses at the crack tip of a 2024-T3 aluminum plate. This involves a numerical analysis using the finite element method (FEM) to estimate the reduction in the J-integral value, with the goal of identifying how various parameters related to the patch materials, adhesive properties and loading conditions influence the structural integrity of the repaired plate.Design/methodology/approachThe methodology of this research involves conducting a numerical analysis using the FEM to estimate the reduction in the J-integral value at the crack tip of a 2024-T3 aluminum plate. Three types of patches – metal, composite and functionally graded material (FGM) – were examined under tensile loading conditions, and Adekit-A140 adhesive was used to bond these repair patches to the aluminum plate.FindingsThe analysis considered various parameters, including crack length, the nature of fibers in the composite material, the gradation exponent for FGM patches and the nature of the face in contact with the adhesive for the FGM patch. Additionally, stress analysis was conducted, examining the J-integral values for the plate, shear stress in the adhesive layer and peel stress in the composite patch. The findings highlight that modifying the nature of the repair patch used can significantly enhance the structural integrity of the repaired plate.Originality/valueThe study analyzed J-integral values, shear stress in the adhesive and peel stress in the composite patch. Various parameters, including crack length, fiber type, gradation exponent and adhesive contact face nature, were considered. Results demonstrate that the J-integral value can be significantly reduced by altering the repair patch type, highlighting the effectiveness of customized patch materials in enhancing structural integrity.

Cardiovascular patches applied in congenital cardiac surgery: Current materials and prospects

AbstractCongenital Heart Defects (CHDs) are the most common congenital anomalies, affecting between 4 and 75 per 1000 live births. Cardiovascular patches (CVPs) are frequently used as part of the surgical armamentarium to reconstruct cardiovascular structures to correct CHDs in pediatric patients. This review aims to evaluate the history of cardiovascular patches, currently available options, clinical applications, and important features of these patches. Performance and outcomes of different patch materials are assessed to provide reference points for clinicians. The target audience includes clinicians seeking data on clinical performance as they make choices between different patch products, as well as scientists and engineers working to develop patches or synthesize new patch materials.

Postoperative Aortic Isthmus Size After Arch Reconstruction with Patch Augmentation Predicts Arch Reintervention

Reintervention rates after patch-augmented reconstruction for hypoplastic aortic arch remain moderately high. We analyzed mid-term outcomes of aortic arch reconstruction to define modifiable reintervention risk factors. Excluding Damus-Kaye-Stansel anastomoses and previous arch repair, 338 patients underwent arch reconstruction from 2000-2021 at median age 6d (IQR 4-13d) and weight 3.2kg (IQR 2.8-3.7kg). Surgical technique was patch augmentation with coarctectomy ± interdigitation in 269 (80%), isolated patch aortoplasty in 41 (12%), and other reconstruction in 28 (8%). Risk factors for reintervention were assessed using competing risk models. At median follow-up of 3.9y (IQR 1.1-8.0y), 35 (10.4%) patients required reintervention (30 endovascular, 12 surgical, 7 both). Ten-year cumulative incidence of death/transplant and reintervention were 10% (95%CI 4-20%) and 13% (95%CI 8-20%). On univariate analysis, isolated patch aortoplasty (p=0.002), aortic homograft patch material (p=0.006), and postoperative aortic size z-score ≤-2 for each segment were associated with greater risk of reintervention: ascending aorta (p=0.006), proximal (p=0.001) and distal (p=0.005) transverse arch, and aortic isthmus (p<0.001). On multivariable analysis, aortic homograft (HR 6.29, 95%CI 1.94-20.5, p=0.002) and postoperative isthmus z-score ≤-2 (HR 10.5, 95%CI 5.15-21.5, p<0.001) remained significant. Patients with repaired isthmus z-score ≤-2 had 72.8% (95%CI 44.6-94.4%) cumulative incidence of reintervention at 10 years, versus 6.8% (95%CI 4.1-11.4%) in those with z-score >-2. Aortic undersizing during patch-augmented reconstruction of hypoplastic aortic arch results in over 10% rate of reintervention at mid-term follow-up. Achieving adequate postoperative arch size is critical for preventing reintervention, with aortic isthmus size being of utmost importance.

Longitudinal valvotomy of anterior leaflet for endoscopic transmitral myectomy for hypertrophic obstructive cardiomyopathy.

Transmitral myectomy for hypertrophic obstructive cardiomyopathy is compatible with minimally invasive surgery compared with traditional transaortic access. It has often been performed in conjunction with mitral valve replacement or temporary detachment of the anterior leaflet from its annulus. We present a novel approach: longitudinal incision at the midline of the anterior mitral leaflet for septal myectomy. The procedure is ideally conducted endoscopically or robotically through the right chest. Cardiopulmonary bypass is established in the usual manner. After cardioplegic arrest, the mitral valve is exposed, and the anterior mitral leaflet is incised longitudinally at the midline. Both parts of the leaflet are tentatively fixed to the atrial wall with sutures to keep them open. Using the look-up mode of a 30° scope, the right cusp of the aortic valve is observed. Myectomy is initiated close to the aortic annulus using the pure-cut mode of electrocautery and scissors, then extended apically as necessary. After myectomy, the anterior leaflet is reapproximated with interrupted sutures. This technique is simpler than the detachment of the anterior leaflet and does not require patch materials that could lead to durability issues for the reconstruction of the anterior leaflet.

HoloPatch: improving intracardiac patch fit through holographically modelled templates.

Structural heart defects, including congenital ventricular septal defect closure or intracardiac rerouting, frequently require surgical reconstruction using hand-cut patch materials. Digitally modelled patch templates may improve patch fit and reduce outflow tract obstruction, residual defect risk, and conduction system damage. In this study, we benchmarked mixed-reality and a desktop application against a digitalized model of a real implanted patch. Ten patients scheduled for the repair of various defects consented to prospective inclusion in the study. After surgery, a digital model of the implanted patch was created from the residual material. Five clinical experts created 10 digital patches, 1 per patient, both in mixed-reality and desktop application, for comparison with the reference measurements, including the digitalized model of the real patch used during the surgery. Subjective residual shunt risk prediction was performed using both modalities. Digital patches created in mixed-reality closely matched the surgical material, whereas those created using desktop applications were significantly smaller. Different evaluators showed varying preferences for the application of the residual shunt risk and area. Digitally created patches can assist surgeons in preoperatively sizing of patch implants, potentially reducing post-operative complications.

Preparation and Performance of a Novel Polyurethane Microporous Film on Polypropylene Medical Mesh Surface

This study aims to develop a medical patch surface material featuring a microporous polyurethane (PU) membrane and to assess the material's properties and biological performance. The goal is to enhance the clinical applicability of pelvic floor repair patch materials. PU films with a microporous surface were prepared using PU prepolymer foaming technology. The films were produced by optimizing the PU prepolymer isocyanate index (R value) and the relative humidity (RH) of the foaming environment. The surface morphology of the PU microporous films was observed by scanning electron microscopy, and the chemical properties of the PU microporous films, including hydrophilicity, were analyzed using infrared spectroscopy, Raman spectroscopy, and water contact angle measurements. In vitro evaluations included testing the effects of PU microporous film extracts on the proliferation of L929 mouse fibroblasts and observing the adhesion and morphology of these fibroblasts. Additionally, the effect of the PU microporous films on RAW264.7 mouse macrophages was studied. Immune response and tissue regeneration were assessed in vivo using Sprague Dawley (SD) rats. The PU films exhibited a well-defined and uniform microporous structure when the R value of PU prepolymer=1.5 and the foaming environment RH=70%. The chemical structure of the PU microporous films was not significantly altered compared to the PU films, with a significantly lower water contact angle ([55.7±1.5]° ) compared to PU films ([69.5±1.7]° ) and polypropylene (PP) ([ 104.3±2.5]°), indicating superior hydrophilicity. The extracts from PU microporous films demonstrated good in vitro biocompatibility, promoting the proliferation of L929 mouse fibroblasts. The surface morphology of the PU microporous films facilitated fibroblast adhesion and spreading. The films also inhibited the secretion of tumor necrosis factor-α (TNF-α) and interleukin (IL)-1β by RAW264.7 macrophages while enhancing IL-10 and IL-4 secretion. Compared to 24 hours, after 72 hours of culture, the expression levels of TNF-α and IL-1β were reduced in both the PU film and PU microporous film groups and were significantly lower than those in the PP film group (P<0.05), with the most notable decreases observed in the PU microporous film group. IL-10 and IL-4 levels increased significantly in the PU microporous film group, surpassing those in the PP film group (P<0.01), with the most pronounced increase in IL-4. The PU microporous film induced mild inflammation with no significant fibrous capsule formation in vivo. After 60 days of implantation, the film partially degraded, showing extensive collagen fiber growth and muscle formation in its central region. The PU microporous film exhibits good hydrophilicity and biocompatibility. Its surface morphology enhances cell adhesion, regulates the function of RAW264.7 macrophages, and promotes tissue repair, offering new insights for the design of pelvic floor repair and reconstruction patch materials.

Instantly adhesive and ultra-elastic patches for dynamic organ and wound repair

Bioadhesive materials and patches are promising alternatives to surgical sutures and staples. However, many existing bioadhesives do not meet the functional requirements of current surgical procedures and interventions. Here, we present a translational patch material that exhibits instant adhesion to tissues (2.5-fold stronger than Tisseel, an FDA-approved fibrin glue), ultra-stretchability (stretching to >300% its original length without losing elasticity), compatibility with rapid photo-projection (<2 min fabrication time/patch), and ability to deliver therapeutics. Using our established procedures for the in silico design and optimization of anisotropic-auxetic patches, we created next-generation patches for instant attachment to tissues while conforming to a broad range of organ mechanics ex vivo and in vivo. Patches coated with extracellular vesicles derived from mesenchymal stem cells demonstrate robust wound healing capability in vivo without inducing a foreign body response and without the need for patch removal that can cause pain and bleeding. We further demonstrate a single material-based, void-filling auxetic patch designed for the treatment of lung puncture wounds.

Repair of damaged composite materials after patching experimental investigation of influencing factors

In this study, an experimental study was conducted on the reuse of composite materials after they were damaged. Since composite materials are difficult to recycle and reuse, their presence as waste in the environment is an ecological problem. Therefore, it is more convenient and economical to disassemble the damaged parts and make repairs instead of using new materials. In addition, due to the high cost of these materials, their repairs are preferred. For this study, after glass and carbon fiber-reinforced layer composite plates/sheets were produced, damage in the form of a 10 mm round hole was created. These damaged areas were made ready for repair by applying mechanical processes around them. For repair procedures, different adhesives and patches were applied under appropriate laboratory conditions, and the damaged samples were repaired. Various factors were taken into consideration during the repairs. These factors included the W/D ratio, adhesive thickness, adhesive type, fiber reinforcement angle change in the patch and base material (0, 15, 30, 45), patch thickness, and patch geometry. As a result, different destructive tests were applied to these repaired samples and thus the damage loads of each repair were determined. The results of these damage loads obtained for different factors were compared with the results of the current study in the literature and displayed in plots.

BIOPATCH GRAFTING OF LARGE OR RECALCATRANT OSTEOCHONDRAL DEFECTS OF THE TALUS

IntroductionLarge osteochondral defects (OCD) of the talus present a difficult management conundrum. We present a series of Maioregen xenograft patches applied through an open approach, early lessons from the technique and good early outcomes, in patients who are otherwise looking at ankle salvage techniques.Results16 patients underwent open patch procedures, performed by a single surgeon, over a 30 month period. 12 males, and 4 females with age at presentation from 21–48. The majority were young, male, in physical employment with active sporting interest. MoxFQ, and E5QD were collected preop, 3, 6, 12 month postoperatively. There were significant improvements in ROM, pain, and scores in the cohort. 3 cases returned to Theatre, 1 for a concern about late infection, which settled with good outcome, and a further 2 with metalwork / adhesions.ConclusionEarly results suggest that this patch technique may be useful in prolonging the longevity of the TTJ, where micro fracture has failed, or the lesion is so large that it would likely be futile. Patients rescoped demonstrated good integration of the patch material, with stability and functional improvement. There may be a place for this technique in the management of large lesions, particularly in young patients where preservation is desired over joint salvage.

A high-performance slotted bow-tie nano graphene antenna for optical frequency application with silicon lens and stacked aligning layers

A new Graphene nano-antenna has been designed and proposed in this paper for optical frequency applications with optimized gain performance. The proposed design uses a Silicon Lens and subsequent layers to match the dielectric constant between the antenna and air. The different patch materials are taken and studied for better results. The proposed antenna has been simulated upon a Highly resistive silicon substrate having a high dielectric constant of 11.9. The base of the proposed antenna is designed on a square substrate of 6000μm length and 300μm height. The slotted “bow-tie” antenna is placed on it with an aperture area of 156.8μm×42μm. A silicon layer is placed over it for improved performance. Further, it has been optimized by placing 16 stacked aligning layers to match the dielectric constants. The gain and efficiency improvement are achieved after each layer or coating over the lens. The resonant frequencies obtained are 0.4THz, 1THz, and 2.2THz having triple bands. The maximum gain obtained is 36.89 dB and the maximum radiation efficiency is 97%. HFSS 21.0 software is the used environment for the simulation and optimization.

Janus orthogonal nanofiber membrane containing CPP@PDA for skull base reconstruction

In neurosurgery procedures, cerebrospinal fluid leakage is a commonly encountered complication. Reconstructing skull base defects with patch materials can reduce the risk of cerebrospinal fluid leakage which can lead to serious issues such as infection, meningitis, arachnoiditis, and delayed wound healing. An ideal skull base reconstruction material should not only serve as a leak-proof barrier but also promote skull base bone regeneration. To fulfill this challenge, this research designed and fabricated a Janus orthogonal bilayer nanofiber membrane (OPCL/PG-PCPP). The aligned PCL (APCL) nanofibers were constituted as the top layer to resist cerebrospinal fluid leakage, while the perpendicular PCL/gelatin (APG) fibers with calcium polyphosphate encapsulated polydopamine nanoparticles (CPP@PDA, labeled as PCPP) were designed as the bottom layer (APG-PCPP) to facilitate osteoblast migration and osteogenic differentiation. Among these, APG-1%PCPP nanofibers demonstrated the most effective induction of osteogenic differentiation in bone marrow mesenchymal stem cells (rBMSCs). Subsequent in vivo animal experiments revealed that the bone surface area (BS), bone volume fraction (BV/TV), and number of trabeculae (Tb.N) in the APG-1%PCPP group were twice as high as those in the control group, which confirmed the good osteogenic potentials. Therefore, due to its unique leak-proof and osteoinductive properties, the OPCL/PG-PCPP membrane holds promise as an applicable skull base reconstruction material in the field of neurosurgery.

Patches in Congenital Diaphragmatic Hernia: A systematic review.

This systematic review aims to evaluate current choice in practice and outcomes of biomaterials used in patch repair of congenital diaphragmatic hernia (CDH). Multiple biomaterials, both novel and combinations of pre-existing materials are employed in patch repair of large size CDH. Literature search was performed across Embase, Medline, Scopus, and Web of Science. Publications that explicitly reported patch repair, material used and recurrences following CDH repair were selected. Sixty-three papers were included, presenting data on 4598 patients of which 1811 (39.4%) were managed using 19 types of patches. Goretex® (GTX) (n=1259) was the most frequently employed patch followed by Surgisis® (n=164), Dualmesh® (n=114), Marlex®/GTX® (n=56), Tutoplast dura® (n=40), Dacron® (n=34), Dacron®/GTX® (n=32), Permacol® (n=24), Teflon® (n=24), Surgisis®/GTX® (n=15), Sauvage® Filamentous Fabric (n=13), Marlex® (n=9), Alloderm® (n=8), Silastic® (n=4), Collagen coated Vicryl® mesh (CCVM) (n=1), Mersilene® (n=1), and MatriStem® (n=1) Biomaterials were further subgrouped as: Synthetic non-resorbable (SNOR) (n=1458), Natural-resorbable (NR) (n=249), Combined natural and synthetic non-resorbable (NSNOR) (n=103), and Combined natural and synthetic resorbable (NSR) (n=1). Overall recurrence rate for patch repair was 16.8% (n=305). For patch types with n>20, recurrence rate was lowest in GTX/Marlex (3.6%), followed by Teflon (4.2%), Dacron (5.6%), GTX (13.8%), Permacol (16.0%), Tutoplast Dura (17.5%), Dualmesh (20.2%), SIS/GTX (26.7%), SIS (36.6%), and Dacron/GTX (37.5%).When analysed by biomaterial groups, recurrence was highest in NSR (100%), followed by NR (32.9%), NSNOR (17.5) and SNOR the least (14.0%). In this cohort, over one-third of CDH were closed using patches. To date, 19 patch types/variations have been employed for CDH closure. GTX is the most popular, employed in 70% of patients; however excluding smaller cohorts (n<20) GTX/Marlex is associated with the lowest recurrence rate (3.6%). SNOR was the material type least associated with recurrence while NSR experienced recurrence in every instance.

Multidetector Computed Tomography Assessment of Anatomical Ventricular Tachycardia Isthmuses in Repaired Tetralogy of Fallot

BackgroundTetralogy of Fallot (TOF) is associated with risk for sustained monomorphic ventricular tachycardia (VT). Preemptive electrophysiology study before transcatheter pulmonary valve placement is increasing, but the value of MDCT for anatomical VT isthmus assessment is unknown. ObjectivesThe purpose of this study was to determine the impact of multidetector computed tomography (MDCT) in the evaluation of sustained monomorphic VT for repaired TOF. MethodsConsecutive pre–transcatheter pulmonary valve MDCT studies were identified, and anatomical isthmus dimensions were measured. For a subset of patients with preemptive electrophysiology study, MDCT features were compared with electroanatomical maps. ResultsA total of 61 repaired TOFs with MDCT were identified (mean 35 ± 14 years, 58% men) with MDCT electroanatomical map pairs in 35 (57%). Calcification corresponding to patch material was present in 46 (75%) and was used to measure anatomical VT isthmuses. MDCT wall thickness correlated positively with number of ablation lesions and varied with functional isthmus properties (blocked isthmus 2.6 mm [Q1, Q3: 2.1, 4.0 mm], slow conduction 4.8 mm [Q1, Q3: 3.3, 6.0 mm], and normal conduction 5.6 mm [Q1, Q3: 3.9, 8.3 mm]; P < 0.001). A large conal branch was present in 6 (10%) and a major coronary anomaly was discovered in 3 (5%). Median ablation lesion distance was closer to the right vs the left coronary artery (10 mm vs 15 mm; P = 0.01) with lesion-to-coronary distance <5 mm in 3 patients. ConclusionsMDCT identifies anatomical structures relevant to catheter ablation for repaired TOF. Wall thickness at commonly targeted anatomical VT isthmuses is associated with functional isthmus properties and increased thermal energy delivery.

A unique variation of the jugular veins and its clinical significance.

The authors report a rare variation of the anterior jugular and internal jugular veins in a 78-year-old male donor. An enlarged and curved left anterior jugular vein (AJV) was formed as the continuation of the left common facial vein (CFV). The left AJV's diameter was wider than the internal jugular vein (IJV) and measured around 5 mm greater than the IJV's diameter and a channel connected the two veins. The right AJV and CFV continued from the two divisions of the right facial vein. The right AJV's diameter was smaller than the right IJV's diameter. The right external jugular vein was absent. No concurrent pathology supported the abnormal dimension of the left AJV and the findings were indicative of a variant anatomy. These variations have rarely been reported and have important clinical correlations. Failed IJV cannulation may result if the variant neck veins are missed. However, variant veins may serve as collateral channels and patch material in IJV reconstruction, carotid angioplasty, and ventricular-jugular shunts.

Tissue-engineered and autologous pericardium in congenital heart surgery: comparative histopathological study of human vascular explants.

The goal of this histological study was to assess the biocompatibility of vascular patches used in the repair of congenital heart defects. We examined tissue-engineered bovine (n = 7) and equine (n = 7) patches and autologous human pericardium (n = 7), all explanted due to functional issues or follow-up procedures. Techniques like Movat-Verhoeff, von Kossa and immunohistochemical staining were used to analyse tissue composition, detect calcifications and identify immune cells. A semi-quantitative scoring system was implemented to evaluate the biocompatibility aspects, thrombus formation, extent of pannus, inflammation of pannus, cellular response to patch material, patch degradation, calcification and neoadventitial inflammation. We observed distinct material degradation patterns among types of patches. Bovine patches showed collagen disintegration and exudate accumulation, whereas equine patches displayed edematous swelling and material dissolution. Biocompatibility scores were lower in terms of cellular response, degradation and overall score for human autologous pericardial patches compared to tissue-engineered types. The extent of pannus formation was not influenced by the type of patch. Bovine patches had notable calcifications causing tissue hardening, and foreign body giant cells were more frequently seen in equine patches. Plasma cells were frequently detected in the neointimal tissue of engineered patches. Our results confirm the superior biocompatibility of human autologous patches and highlight discernible variations in the changes of patch material and the cellular response to patch material between bovine and equine patches. Our approach implements the semi-quantitative scoring of various aspects of biocompatibility, facilitating a comparative quantitative analysis across all types of patches, despite their inherent differences.

Effectiveness and Safety of Different Patch Materials for Supravalvar Aortic Stenosis (Middle-Term Outcomes).

To determine the effectiveness and safety of different patch materials in the treatment of pediatric patients with congenital supravalvular aortic stenosis (SVAS). 218 consecutive SVAS patients (age 14 years) who underwent surgery from Beijing Fuwai and Yunnan Fuwai hospital between 2002 and 2020 were included. Patients were divided into the pericardium patch group (133 (61.0%)), modified patch group (43 (19.7%)) and artificial patch group (42 (19.3%)). The primary safety endpoint was patch-related adverse complications (post-operation patch hemorrhage or aortic sinus aneurysm at 2-year follow-up). The primary effectiveness outcome was the re-operation or restenosis at 2-year follow-up. Multivariable cox regression was used to obtain the hazard ratio (HR). The median age at operation was 43.5 months (IQR 24.0-73.0). Only three patients had patch-related adverse complications, and no difference existed among the three groups (p = 0.763). After a median follow-up of 24.0 months (IQR 6.0-48.0), patients with a pericardium patch had a lower re-operation or restenosis rate compared with the other two groups (pericardium patch vs modified patch, HR = 0.30, 95% CI 0.12-0.77; pericardium patch vs artificial patch, HR = 0.33, 95% CI 0.13-0.82), even in the main subgroup and sensitivity analysis. In pediatric patients, the safety of autologous pericardium patch is acceptable, along with lower rates of middle-term re-operation or restenosis. http://www.chictr.org.cn, number: ChiCTR2300067851.

Graphene-based patch antenna array on photonic crystal substrate at terahertz frequency band

ABSTRACT In this paper, initially a photonic crystal is proposed with a periodic air gap and its performance is investigated at terahertz frequencies by varying the radius of the air gap. Then a microstrip array antenna on the 2-D photonic crystal using graphene sheet as patch material is designed and its electromagnetic characteristics are analysed and compared with those of the existing non-air gap antenna. The suggested antenna also operates in the multi-frequency terahertz range. Using a photonic band gap (PBG), crystal substrate causes the return loss to rise from −29 to −44 dB. Additionally, the antenna array's bandwidth was increased from 40 to 110 GHz. By using PBG, the gain of the suggested antenna is increased by up to 13 dB, as opposed to 4.81 dB for a substrate that does not use PBG.

In vivo application of a glutaraldehyde-free, UVA/riboflavin cross-linked bovine pericardium confirms suitability for cardiovascular substitutes

Glutaraldehyde (GA)-treated bovine pericardium is still the gold standard for the fabrication of bioprostheses needed for the surgical treatment of valvular malfunction. Although excellent stability and low immunogenicity are accomplished, the application of GA is considered to be causal for structural valve deterioration, diminishing the long-term durability of bioprosthetic tissue. The novel GA-free SULEEI-treatment of bovine pericardium combines decellularization, riboflavin/UVA-cross-linking, and low-energy electron beam irradiation. In the present study, we initiated an in vivo application. We used a subcutaneous rat model to compare the immune and tissue responses, calcification propensity, and biomechanical properties of the alternatively prepared SULEEI bovine pericardial tissue with standard glutaraldehyde-fixed and industrially produced bovine pericardial patch material. SULEEI pericardium evokes a similar immune reaction and tissue response as the control standard bovine patch material. The calcification propensity of SULEEI tissue was low, and biomechanical analysis revealed a heterogeneous but similar pattern in tissue stiffness compared to the control patch. The results of this study highlight the potential of SULEEI-treated bovine pericardial tissue as a candidate for cutting-edge cardiovascular and valvular biomaterials in reconstructive surgery.

Hydro-mechanical analysis of water-induced pothole patch failure in asphalt pavement

Pothole repair is one of most common roadway maintenance to improve driving comfort and reduce safety risk. This study aimed to conduct hydro-mechanical analysis of water-induced pothole patch failure in asphalt pavement. Three-dimensional finite element models are used to analyze the coupled hydraulic and mechanical responses of surface patching under moving traffic loading considering different wheel path locations and asphalt patch sizes. The model results under dry and saturated conditions were validated against field measurements and simulation results from the literature, respectively. Laboratory tests were conducted to measure dynamic modulus and permeability of asphalt patch material. Analysis results show that regardless of patch size and wheel path, the maximum pore water pressure occurs either at the patch body or the interface between the patch and surrounding pavement when traffic loading approaches the pothole. The hydraulic scouring effect was observed with positive and negative pore pressure under moving loads. The maximum interface shear stress at the interface between the patch and surrounding pavement under traffic loading was found close to the bonding strength, especially for big-shallow patch. The comparison of asphalt patch responses at dry and saturated conditions indicates that water intrusion mainly accelerates edge disintegration of pothole patch.