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Carbon fiber-reinforced polymers (CFRPs) are widely used in high-performance applications, but their inherent brittleness and susceptibility to impact damage remain critical challenges. This study investigated the effect of core–shell rubber (CSR) particles as impact modifiers on the mechanical properties of CFRPs and evaluated patch repair techniques for damaged CFRP panels. Mechanical tests, including flexural, tensile, short-beam, fracture toughness, and impact tests, were conducted on reference and CSR-modified specimens to assess their structural performance. The CSR-modified samples demonstrated significant improvements in energy absorption and fracture toughness, with a 50% increase in impact strength and up to 181% improvement in absorbed energy during Mode I fracture testing. However, slight reductions in flexural and tensile strengths were observed due to the softening effect of CSR particles. Fracture surface analysis revealed distinct failure mechanisms, with Scanning Electron Microscopy imaging showing consistent fiber pull-out behavior in tensile and flexural tests, but more stable delamination propagation in CSR-modified specimens during short-beam shear tests. Patch repair effectiveness was assessed through drop-weight impact tests on damaged panels repaired with patches containing CSRs of two thicknesses. Patches of equal thickness to the damaged panel successfully restored structural integrity and enhanced energy absorption by 37% compared with the reference samples, while thinner patches (as a suggestion to reduce production costs) failed to withstand impact loads effectively. Non-destructive testing (NDT) via ultrasonic C-scans confirmed reduced delamination and damage depth in CSR-modified repaired panels, validating the toughening effect of CSR particles. These findings demonstrate the potential of CSR-modified resins to improve CFRPs' performance and provide effective repair solutions for extending the service life of damaged composite structures, rendering them especially suitable for applications demanding high damage tolerance and durability, including aerospace structures, automotive body panels, and energy-absorbing crash components. [ABSTRACT FROM AUTHOR]

IntroductionCongenital diaphragmatic hernia (CDH) repair is an area of active research. Large defects requiring patches have a hernia recurrence rate of up to 50%. We designed a biodegradable polyurethane (PU)-based elastic patch that matches the mechanical properties of native diaphragm muscle. We compared the PU patch to a non-biodegradable Gore-Tex™ (polytetrafluoroethylene) patch.MethodsThe biodegradable polyurethane was synthesized from polycaprolactone, hexadiisocyanate and putrescine, and then processed into fibrous PU patches by electrospinning. Rats underwent 4 mm diaphragmatic hernia (DH) creation via laparotomy followed by immediate repair with Gore-Tex™ (n = 6) or PU (n = 6) patches. Six rats underwent sham laparotomy without DH creation/repair. Diaphragm function was evaluated by fluoroscopy at 1 and 4 weeks. At 4 weeks, animals underwent gross inspection for recurrence and histologic evaluation for inflammatory reaction to the patch materials.ResultsThere were no hernia recurrences in either cohort. Gore-Tex™ had limited diaphragm rise compared to sham at 4 weeks (1.3 mm vs 2.9 mm, p = 0.003), but no difference was found between PU and sham (1.7 mm vs 2.9 mm, p = 0.09). There were no differences between PU and Gore-Tex™ at any time point. Both patches formed an inflammatory capsule, with similar thicknesses between cohorts on the abdominal (Gore-Tex™ 0.07 mm vs. PU 0.13 mm, p = 0.39) and thoracic (Gore-Tex™ 0.3 mm vs. PU 0.6 mm, p = 0.09) sides.ConclusionThe biodegradable PU patch allowed for similar diaphragmatic excursion compared to control animals. There were similar inflammatory responses to both patches. Further work is needed to evaluate long-term functional outcomes and further optimize the properties of the novel PU patch in vitro and in vivo.Level of evidenceLevel II, Prospective Comparative Study.

This research showcased the use of leftover trash as a substitute for aggregate in mortar combined with saltwater. The raw waste materials underwent analysis using X-ray fluorescence (XRF) in order to determine the component materials and crystalline phases present. The choice of Portland composite cement (PCC) was made because of its durability in a hostile environment. Seawater is used to combat the water crisis and prevent corrosion, thanks to its exceptional resistance to corrosion. The attributes of mortar were assessed in terms of its fresh characteristics (slump and flow table) as well as its mechanical properties (compressive strength, split tensile strength, flexural strength, density, and shrinkage). The findings indicate that the dried mortar waste is suitable as a patch repair material for a substrate with a strength of 20 MPa, but only when utilized in a maximum quantity of 20% and with a water-to-cement ratio of 0.3. The repaired concrete with a strength of 25 MPa did not need any waste containment and had a maximum water-to-cement ratio (W/C) of 0.3, whether combined with saltwater or tap water. The possible role of the mortar containing the dried waste was to be the species for brick and other non-structural. Additionally, the use of an alternative cementitious substance is suggested to enhance the effectiveness of the patch repair material, particularly when paired with cathodic corrosion protection in damaged concrete

In this study, a high-strength carbon fiber reinforced composite laminate for rail vehicles was machined as a perforated sample and repaired by bonding a patch of the same material. The mechanical response of the repaired laminate to a low-velocity impact with energies of 25J and 30J was investigated through experiments and simulations with variations in patch thickness, size radius, and off-axis angle. The finite element simulation model was established in Abaqus/Explicit. The model integrated the progressive damage model based on the 3D-Hashin failure criterion, which can simulate the intralaminar damage of the fiber and the matrix. The cohesive zone model was used to simulate the delamination damage. According to the finite element analysis results, the mechanism and process of impact damage of the repaired laminates were analyzed. Based on the validated finite element model, the effect of patch size, thickness and off-axis angle on impact response was investigated. Patch radius reduced to 15 mm or thickness reduced to 2.1 mm can still resist low-velocity impacts with an energy of 30 J. Although the off-axis angle of the patch had little effect on the impact response of the repaired laminate, an off-axis angle of 90° was effective in suppressing delamination damage within the patch.

Background: Ventricular septal defect is a hole or multiple holes in the interventricular septum. Hearts with these primary defects may have minor coexisting morphologic abnormalities, or may be part of another major cardiovascular anomaly. Peri membranous ventricular septal defects are among the most common cardiac malformations and constitute 80% of these defects. Ventricular septal defects may be small, moderate or large size. Material and Methods: The study was conducted in the Department of Cardiovascular and Thoracic Surgery on patients operated for ventricular septal defects. Results: A total of 9 patients, mostly in second decade, irrespective of age, sex, clinical presentation and surgical outcome were included in the study. Male patients were more. Tachypnoea was the presenting symptom, and pansystolic murmur common clinical observation. Two-dimensional echocardiography was the investigation of choice, and around 80% had peri membranous type of defect. All the patients were operated under cardiopulmonary bypass, patch repair was common surgical procedure. There was no mortality. Conclusion: Early and precise diagnosis, followed by definitive management (Device closure / Open Surgical repair) gives excellent results. [ABSTRACT FROM AUTHOR]

The conventional case of patch repair involves bonding a patch over single damage/hole in the laminate. This work investigates the effect of interaction of two holes on the tensile behavior patch repaired carbon epoxy woven laminates. The specimens of [0°/45°/45°/0°] laminates were repaired with adhesively bonded two-ply [45°]2 external patches. Three different cases of drilled specimens were produced with different hole arrangements viz. specimens with single central hole (SH), with two holes aligned along the longitudinal axis (LH) and with two holes along transverse axis (TH). The two-hole specimens were repaired with two different types, i.e. single large patches (SP) and with the two smaller patches (DP) of combined bonding area equal to the single large patches. Digital image correlation (DIC) was employed to capture strain contours. The results reveal the difference in the load transfer through the patches depending upon the arrangement of holes. The TH repaired specimen exhibit significant load recovery (SP-32.75%, DP-34.62%) while the LH specimens result in very marginal (SP- 6.11%, DP-4.10%) recovery compared to their drilled case. The TH specimen failed by crack growing through both the holes beneath the patch, while the LH specimens failed by the failure through only one hole. The use of single large patch over multiple holes and multiple small patches individually over each hole has no significant influence on load recovery.

An unsaturated polyester resin (UPR) mortar was applied to repair the damage to the tension zone's one-way reinforced concrete (RC) slabs. The load carrying capacity of the patched RC slab is of interest to justify the effectiveness of the repair. The Yield Line Theory (YLT) may be used to estimate the load carrying capacity of patched RC slabs under concentrated load. The results of the YLT are compared with the experimental results to evaluate the validity of the YLT method. The results confirm that patching alters the yield line formation, mainly when the concentrated load is applied close to the patching zone. Subsequently, the YLT method provides a higher load carrying capacity estimation deviation for slabs with a loading point near the patching zone. On the other hand, the YLT method estimates load carrying capacity accurately when the loading point is away from the patching zone.

Renal artery aneurysms are rare. Indications for management include size > 3 cm, female gender within childbearing age, pain, hematuria, medically refractory hypertension, thromboembolism, dissection, and rupture. Management options include endovascular, open repair, and ex vivo approaches. A 43-year-old female with a history of polycystic kidney disease, solitary kidney, and uncontrolled hypertension was found to have a proximal large renal aneurysm on imaging. The patient underwent an in situ open aneurysm resection, temporary shunt insertion, and patch repair with good postoperative outcomes. Whereas previous studies showed the success of ex vivo repair and autotransplantation in large aneurysms with solitary kidneys, our case demonstrated that in situ open repair and patch with the use of a temporary shunt is a feasible and effective option. In a patient with a solitary kidney and large proximal renal artery aneurysm, an in situ open approach and patch repair with shunt insertion should be considered. [ABSTRACT FROM AUTHOR]

The presence of a geometric discontinuity such as a crack or a notch can cause the failure of a structure during its use. Under various mechanical or thermal stresses, a high concentration of stresses can take place at the level of these discontinuities, which in most cases will lead to the total failure of the structure. The service life of these structures can be improved with the use of the repair technique by bonding a composite patch. This technique is of significant interest in several fields, especially with the use of composite materials. This technique is widely used in aeronautics and ensures a long life of damaged structures. Current research aims to optimize the shape size and fiber's nature of this composite patch in order to ensure good load transfer by reducing the stresses in the damaged area. In this work, a finite element method is used to analysis the effect of the shape of the patch on the global response of a 2024-T3 aluminum structure in the presence of a central circular notch. The composite patch is of the carbon/epoxy type bonded through an A-140 Adekit type adhesive on the damaged part of the plate. The analysis consists in determining the force-displacement curves of the repaired structure by using the combination of the two techniques, XFEM for the damage of the aluminum plate 2024-T3 by the automatic creation of the crack and CZM for the analysis of the adhesive debonding. The analysis takes into account the damage in the plate and in the adhesive. However, for the composite patch, and since there will be no damage, we have just analyzed the effect of its shape and essentially the shape of its edges on the load transfer and consequently on the resistance of the structure under loading in tension. Two main patch shapes have been highlighted, namely the square and circular shape. The results show clearly that the shape of the patch�s edges has an impact on the stresses reduction in the plate and subsequently ensures good resistance in terms of force-displacement curve and consequently delays the peeling of the adhesive

Aerolysin family pore-forming toxins damage the membrane, but membrane repair responses used to resist them, if any, remain controversial. Four proposed membrane repair mechanisms include toxin removal by caveolar endocytosis, clogging by annexins, microvesicle shedding catalyzed by MEK, and patch repair. Which repair mechanism aerolysin triggers is unknown. Membrane repair requires Ca2+, but it is controversial ifCa2+ flux is triggered by aerolysin. Here, we determined Ca2+ influx and repair mechanisms activated by aerolysin. In contrast to what is seen with cholesterol-dependent cytolysins (CDCs), removal of extracellular Ca2+ protected cells from aerolysin. Aerolysin triggered sustained Ca2+ influx. Intracellular Ca2+ chelation increased cell death, indicating that Ca2+-dependent repair pathways were triggered. Caveolar endocytosis failed to protect cells from aerolysin or CDCs. MEK-dependent repair did not protect against aerolysin. Aerolysin triggered slower annexin A6 membrane recruitment compared to CDCs. In contrast to what is seen with CDCs, expression of the patch repair protein dysferlin protected cells from aerolysin. We propose aerolysin triggers a Ca2+-dependent death mechanism that obscures repair, and the primary repair mechanism used to resist aerolysin is patch repair. We conclude that different classes of bacterial toxins trigger distinct repair mechanisms. [ABSTRACT FROM AUTHOR]

The impact responses of a patch-repaired carbon-fiber-reinforced polymer (CFRP) specimen under double impacts were compared to study the damage interference mechanism through the combination of experiment and numerical analysis. A three-dimensional finite element model (FEM) with iterative loading based on continuous damage mechanics (CDM) and a cohesive zone model (CZM) was employed to simulate the double-impacts testing with an improved movable fixture at an impact distance of 0 mm–50 mm. The influence of impact distance and impact energy on the damage interference was explored by mechanical curves and delamination damage diagrams of the repaired laminates. When impactors fell within the range of the patch with an impact distance of 0 mm–25 mm at a low level of impact energy, delamination damage of the parent plate caused by the two impacts overlapped, resulting in damage interference. With the continuing increase in impact distance, the damage interference gradually disappeared. When impactors fell on the edge of the patch, the damage area caused by the first impact on the left half of the adhesive film gradually enlarged, and as the impact energy increased from 5 J to 12.5 J, the damage interference caused by the first impact on the second impact was gradually enhanced. [ABSTRACT FROM AUTHOR]

Damage occurring on a reinforced concrete beam (e.g. spalling) can reduce beam’s capacity to withstand external loads. The damage becomes more critical if it is occurred in the shear span since it may lead to shear failure. Patching to the damage zone by suitable patch repair material could be the best option in restoring the shear capacity of the beam. This research investigates the shear recovery of patched reinforced concrete beams with web reinforcement. The patching material used is unsaturated polyester resin mortar. The shear recovery is assessed on the basis of the patched beam’s behavior under flexure-shear load in comparison with those of normal beams. The behavior observed include cracking failure mode, strains of the reinforcements, and load-deflection behavior. The results indicate that the UPR mortar is capable to restore the strength of the damage reinforced concrete beam. The characteristic of UPR mortar (low elastic modulus and high strength) can be the origin of the overall behavior of the patched reinforced concrete beams.

An unsaturated polyester resin (UPR) mortar was applied to repair the damage to the tension zone's one-way reinforced concrete (RC) slabs. The load carrying capacity of the patched RC slab is of interest to justify the effectiveness of the repair. The Yield Line Theory (YLT) may be used to estimate the load carrying capacity of patched RC slabs under concentrated load. The results of the YLT are compared with the experimental results to evaluate the validity of the YLT method. The results confirm that patching alters the yield line formation, mainly when the concentrated load is applied close to the patching zone. Subsequently, the YLT method provides a higher load carrying capacity estimation deviation for slabs with a loading point near the patching zone. On the other hand, the YLT method estimates load carrying capacity accurately when the loading point is away from the patching zone. [ABSTRACT FROM AUTHOR]

Isolated tricuspid valve endocarditis accounts for only 5 to 10 percent of infective endocarditis cases globally. Numerous surgical procedures ranging from simple vegetectomy, creation of neoleaflets or complete replacement by a prosthetic valve have been described. We aimed to evaluate our experience in surgical management of this entity and to formulate an approach for timing, appropriateness and extent of surgery. Patients operated on semi elective/emergency basis had adverse outcome with residual regurgitation and had longer ICU stay. Also, patients who required excision of leaflet and creation of neoleaflets had a higher incidence of regurgitation. This suggests that maximal preservation of native valve lessens the incidence of residual regurgitation. Simple vegetectomy and patch repair of the residual defect offers the best outcome.

The presence of a geometric discontinuity such as a crack or a notch can cause the failure of a structure during its use. Under various mechanical or thermal stresses, a high concentration of stresses can take place at the level of these discontinuities, which in most cases will lead to the total failure of the structure. The service life of these structures can be improved with the use of the repair technique by bonding a composite patch. This technique is of significant interest in several fields, especially with the use of composite materials. This technique is widely used in aeronautics and ensures a long life of damaged structures. Current research aims to optimize the shape size and fiber's nature of this composite patch in order to ensure good load transfer by reducing the stresses in the damaged area. In this work, a finite element method is used to analysis the effect of the shape of the patch on the global response of a 2024-T3 aluminum structure in the presence of a central circular notch. The composite patch is of the carbon/epoxy type bonded through an A-140 Adekit type adhesive on the damaged part of the plate. The analysis consists in determining the force-displacement curves of the repaired structure by using the combination of the two techniques, XFEM for the damage of the aluminum plate 2024-T3 by the automatic creation of the crack and CZM for the analysis of the adhesive debonding. The analysis takes into account the damage in the plate and in the adhesive. However, for the composite patch, and since there will be no damage, we have just analyzed the effect of its shape and essentially the shape of its edges on the load transfer and consequently on the resistance of the structure under loading in tension. Two main patch shapes have been highlighted, namely the square and circular shape. The results show clearly that the shape of the patch's edges has an impact on the stresses reduction in the plate and subsequently ensures good resistance in terms of force-displacement curve and consequently delays the peeling of the adhesive. [ABSTRACT FROM AUTHOR]

The presence of a geometric discontinuity such as a crack or a notch can cause the failure of a structure during its use. Under various mechanical or thermal stresses, a high concentration of stresses can take place at the level of these discontinuities, which in most cases will lead to the total failure of the structure. The service life of these structures can be improved with the use of the repair technique by bonding a composite patch. This technique is of significant interest in several fields, especially with the use of composite materials. This technique is widely used in aeronautics and ensures a long life of damaged structures. Current research aims to optimize the shape size and fiber's nature of this composite patch in order to ensure good load transfer by reducing the stresses in the damaged area. In this work, a finite element method is used to analysis the effect of the shape of the patch on the global response of a 2024-T3 aluminum structure in the presence of a central circular notch. The composite patch is of the carbon/epoxy type bonded through an A-140 Adekit type adhesive on the damaged part of the plate. The analysis consists in determining the force-displacement curves of the repaired structure by using the combination of the two techniques, XFEM for the damage of the aluminum plate 2024-T3 by the automatic creation of the crack and CZM for the analysis of the adhesive debonding. The analysis takes into account the damage in the plate and in the adhesive. However, for the composite patch, and since there will be no damage, we have just analyzed the effect of its shape and essentially the shape of its edges on the load transfer and consequently on the resistance of the structure under loading in tension. Two main patch shapes have been highlighted, namely the square and circular shape. The results show clearly that the shape of the patch’s edges has an impact on the stresses reduction in the plate and subsequently ensures good resistance in terms of force-displacement curve and consequently delays the peeling of the adhesive.

A common form of damage encountered in marine structures is the accumulation of corrosion in susceptible areas, which leads to material wastage. As a result, the structural strength of the members affected is compromised, endangering their safe operation in design loads. Consequently, structural instabilities may occur, such as buckling due to compressive or/and shear loads. An alternative repair practice for preventing such phenomena, approved for secondary load-carrying members, is the application of composite patches to the damaged area. In this preliminary study, this technique is examined in the scope of developing a framework that can be used to find the optimal solution for restoring the buckling strength of a corroded plate. The methods used to achieve this are based on finite element analysis (FEA) and design of experiments (DoE) to statistically analyze the aforementioned numerical calculations. By introducing the composite patch’s percentage coverage of its metal substrate and number of plies as design parameters, a response surface is generated with respect to the obtained factor of safety (regarding its reference uncorroded buckling strength). This list of data points is then evaluated, and an acceptable surface/list of design parameters’ combinations is generated.

Chest wall tumor resection can result in a large defect that can pose a challenge in reconstruction in restoring chest wall contour, maintaining respiratory mechanics, and improving cosmesis. Titanium plates were first introduced for treating a traumatic flail chest, which yielded promising results in restoring chest wall stability. Subsequently, the applications of titanium plates in chest wall reconstruction surgery were demonstrated in case reports and series. Our center has adopted this technique for a decade, and patients are actively followed up after operation. Here, we retrospectively analyze our 10-year experience of using titanium plates and other reconstruction approaches for chest wall reconstruction, in terms of clinical outcomes, complications, and reasons for reoperation to determine long-term safety and efficacy. Thirty-eight patients who underwent chest wall resection and reconstruction surgery were identified. Of these, 11 had titanium plate insertion, 11 had patch repair or flap reconstruction, and the remaining 16 had primary closure of defects. Chest wall reconstruction using titanium plate(s) and patch repair (with or without flap reconstruction) was associated with larger chest wall defects and more sternal resections than primary closure. Subgroup analysis also showed that reconstruction by the titanium plate technique was associated with larger chest wall defects than patch repair or flap reconstruction [286.80 cm2 vs. 140.91 cm2 (p = 0.083)]. There was no 30-day hospital mortality. Post-operative arrhythmia was more commonly seen following chest wall reconstruction compared with primary closure (p = 0.041). Furthermore, more wound infections were detected following the use of titanium plate reconstruction compared with the patch repair (with or without flap reconstruction) approach (p = 0.027). In conclusion, the titanium plate system is a safe, effective, and robust approach for chest wall reconstruction surgery, especially in tackling larger defect sizes.

Abstract Background Symptomatic Bochdalek hernias are found mainly in infants in respiratory distress and occur rarely in adults. Case presentation We report a rare case of Bochdalek hernia associated with developmental abnormalities in an adult who exhibited acute chest pain and dyspnea on exertion. Conclusions This case highlights the importance of the differential diagnosis of acute left-sided chest pain and antenatal examination.

Through this study, a numerical simulation based on 3D in order to investigate the effect of crack-front shape on the stress intensity factor and fatigue crack growth behavior of center cracked aluminum plate repaired asymmetrically with bonded composite patch. Consequently, skew degree it is a significant effect on stress intensity factor (SIF) distribution along the crack front in thick panels more than in thin panels. Moreover, fatigue life was calculated using different averaged stress intensity factor of patched panel determined from uniform crack front model and skew crack front model obtained from FEM and when comparing fatigue life values obtained from the finite element model with experimental values were shown a good agreement.

Aortobronchial fistula is a rare cause of repeated hemoptysis and a potentially fatal condition if left untreated. We present the case of a 40-year-old man with repeated hemoptysis, excessive cough, and epistaxis ongoing for several days after SARS-CoV-2 pneumonia diagnosis. The patient had a history of patch aortoplasty for aortic coarctation and aortic valve replacement with a mechanical valve for aortic insufficiency due to bicuspid aortic valve at the age of 24. Computed tomography scan performed at presentation revealed a severely dilated ascending aorta, a thoracic aorta pseudoaneurysm at the site of the former coarctation, an aortobronchial fistula suggested by the thickened left lower lobe apical segmental bronchus in contact with the pseudoaneurysm and signs of alveolar hemorrhage in the respective segment. The patient was treated with thoracic endovascular aneurysm repair (TEVAR) after prior hemi-aortic arch debranching and transposition of the left common carotid artery and subclavian artery through a closed-chest surgical approach. Our case report together with a systematic review of the literature highlight the importance of both considering an aortobronchial fistula in the differential diagnosis of hemoptysis in patients with prior history of thoracic aorta surgical intervention, regardless of associated pathology, and of taking into account endovascular and hybrid techniques as an alternative to open surgical repair, which carries a high risk of morbidity and mortality.

In this study, the impact response, damage accumulation, interlaminar and intralaminar energy dissipation distributions of patch-repaired carbon fiber reinforced polymer (CFRP) laminates under repeated impacts were studied by combining experimental and numerical methods. A three-dimensional finite element model (FEM) based on continuum damage mechanics (CDM) and cohesive zone model (CZM) was performed using ABAQUS/Explicit to simulate the impact experiments (at impact energy of 10 J ~ 20 J). The influence of impact energy (5 J ~ 15 J) on damage accumulation, interlaminar and intralaminar energy dissipation was explored by numerical calculations. It was found that the sudden drop of the force-time curve was an important signal of serious internal damage of the patch; at impact energy of 5 J ~ 12.5 J, the impact parameters such as impact time, peak force and maximum deflection increased with the increase of impact times; at impact energy of 5 J ~ 12.5 J, the delamination damage after the first impact and the corresponding interlaminar energy dissipation increased slightly with the increase of impact times; the delamination damage can be used as an important factor to reflect the damage accumulation degree of patch-repaired laminates under repeated impacts.

Abstract Background Surgery for infective endocarditis involving the aorto-mitral curtain (AMC) is challenging and requires extensive incisions and complex reconstruction procedures. However, in patients with preserved aortic annulus, reconstruction of the AMC is possible using a simple technique with limited incisions. Case presentation A handmade bovine three-portion pericardial patch was used to reconstruct the AMC in a patient with severe endocarditis requiring double valve replacement; the technique allowed for steady anchorage of prosthetic valves without additional incisions other than conventional aortotomy and atriotomy. Postoperative echocardiography revealed normal cardiac function and no significant perivalvular leakage. The patient displayed complete recovery and was discharged on postoperative day 33. The patient was symptom-free at his 1-year follow-up and displayed normal laboratory and echocardiographic findings. Conclusion The bovine three-portion pericardial patch is useful for reconstructing the AMC in patients with infective endocarditis accompanied by preserved aortic annulus.

Isolated tricuspid valve endocarditis accounts for only 5 to 10 percent of infective endocarditis cases globally. Numerous surgical procedures ranging from simple vegetectomy, creation of neoleaflets or complete replacement by a prosthetic valve have been described. We aimed to evaluate our experience in surgical management of this entity and to formulate an approach for timing, appropriateness and extent of surgery. Patients operated on semi elective/emergency basis had adverse outcome with residual regurgitation and had longer ICU stay. Also, patients who required excision of leaflet and creation of neoleaflets had a higher incidence of regurgitation. This suggests that maximal preservation of native valve lessens the incidence of residual regurgitation. Simple vegetectomy and patch repair of the residual defect offers the best outcome. [ABSTRACT FROM AUTHOR]

This manuscript presents experimental results of compression tests of repaired sandwich structure typical of a launch vehicle Payload Adapter Fitting (PAF) that is being considered for the National Aeronautics and Space Administration's (NASA) Space Launch System (SLS) launch vehicle. Specimens with 8-ply quasi-isotropic carbon/epoxy face sheets and aluminum honeycomb core were damaged with representations of misdrilled holes, barely visible impact damage (BVID) or visible impact damage (VID). A patch repair technique not requiring removal of any material is presented and assessed for residual in-plane compressive load-carrying capability on each of the three types of damage. Edgewise compression tests on specimens demonstrated the repairs could recover all measured undamaged compressive load-carrying capability of the misdrilled hole and BVID specimens. For the specimens with VID, an average of about 91% of the average measured undamaged compressive load carrying capability was recovered indicating that larger patches, or perhaps removal and replacement of the damaged material, may be needed for more severe damage if all the measured undamaged compression strength needs to be regained. [ABSTRACT FROM AUTHOR]

A 3-D finite element analysis was conducted on a thin aluminum plate with a 45 ° inclined central crack. A modeling of the bonding repair with composite patch of different shapes was carried out. In addition to the patch shapes studied in the literature, a new butterfly shape was proposed. The latter is defined by a length H, a width B and a neck C in the middle. The main objective is to analyze the effect of patch geometry on the rate of decrease of stress intensity factors. This rate is characterized by a coefficient R which combines between the mode I and the mode II of the rupture (KI and KII). Thus, an optimization of the patch shape is made with respect to the effectiveness in decreasing the stress intensity factor. The comparison between the results obtained with the different patch shapes has shown that the butterfly-shaped patch is more effective for relatively small surfaces. On the other hand, the extended octagon shape has been shown to be more effective for higher patch surfaces.

This paper presents results from a field study of asphaltic pavement patching operations performed by three different contractors working in a total of ten sites. It forms part of an ongoing research programme towards improving the performance of pothole repairs. Thermal imaging technology was used to record temperatures of the patching material throughout the entire exercise, from the stage of material collection, through transportation to repair site, patch forming, and compaction. Practical complications occurring during patch repairs were also identified. It was found that depending on the weather conditions, duration of the travel and poor insulation of the transported hot asphalt mix, its temperature can drop as high as 116.6 °C over the period that the reinstatement team travel to the site and prepare the patch. This impacting is on the durability and performance of the executed repairs. Cold spots on the asphalt mat and temperature differentials between the new hot-fill asphalt mix and existing pavement were also identified as poorly compacted areas that were prone to premature failure. For example, over the five-minute period, the temperature at one point reduced by 33% whereas the temperatures of nearby areas decreased by 65% and 71%. A return visit to the repair sites, three months later, revealed that locations where thermal segregation was noted, during the patching operation, had failed prematurely.

Background: Symptomatic Bochdalek hernias are found mainly in infants in respiratory distress and occur rarely in adults.Case Presentation: We report a rare case of Bochdalek hernia associated with developmental abnormalities in an adult who exhibited acute chest pain and dyspnea on exertion.Conclusions: This case highlights the importance of the differential diagnosis of acute left-sided chest pain and antenatal examination. [ABSTRACT FROM AUTHOR]

Through this study, a numerical simulation based on 3D in order to investigate the effect of Crack-front shape on the stress intensity factor and fatigue crack growth behavior of center cracked aluminum plate repaired asymmetrically with a bonded composite patch. Consequently, Skew degree is a significant effect on stress intensity factor (SIF) distribution along the crack front in thick panels more than thin panels. Moreover, Fatigue life was calculated using different averages stress intensity factor of patched panel determined from the uniform crack front model and skew crack front model obtained from FEM and when comparing fatigue life values obtained from the finite element model with experimental values were shown a good agreement.

Congenital diaphragmatic hernias are primarily found in infants and have a high mortality rate due to neonatal respiratory distress. The most common type of congenital diaphragmatic hernia is Bochdalek hernia, which occurs in the posterolateral diaphragm, with the left side being the most commonly affected. However, congenital diaphragmatic hernias are extremely rare in adults and are often misdiagnosed due to their subtle symptoms. Therefore, we suggest that a contrast-enhanced CT scan should be used for early screening and diagnosis in all patients with sudden severe pain or recurrent ambiguous symptoms in the chest and abdomen. This case report presents a rare occurrence of Bochdalek hernia in an adult male. The patient experienced nonspecific abdominal symptoms after eating. The hernia resulted in the displacement of the left kidney, the transverse colon of the splenic flexure, and most of the stomach into the thoracic cavity. This displacement led to atelectasis of the left lung, which reached three-fifths of its capacity. The patient underwent successful treatment using a combination of laparoscopy and open surgery. Follow-up CT scans conducted two weeks, three months, and one year later revealed a stable condition with no complications., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2024, Hu et al.)

Purpose: Infective endocarditis (IE) remains a prevalent and life-threatening disease. The choice to repair or replace the infected valve still remains a matter of debate, especially in aortic valve (AV) infections. We retrospectively analyze our two decades of experience in aortic valve repair (AVr) in IE. Long-term outcomes are described with particular attention to the impact of valve configuration and the use of patch techniques. Methods: From September 1998 to June 2017, 42 patients underwent AVr in a single center for IE. Techniques include leaflet patch repair and resuspension and aortic annulus stabilization. Results: Hospital mortality was 2.4% (n = 1). The median follow-up was 90.6 months. Survival was 89 ± 9.4% and 76.6 ± 16% at 5 and 10 years, respectively, with no significant differences between tricuspid aortic valve (TAV) and bicuspid aortic valve (BAV). Freedom from reoperation was 100% and 92.9 ± 7.1% in TAV and 81.8 ± 18.2% and 46.8 ± 28.8% in BAV at 5 and 10 years, respectively (TAV vs BAV, p = 0.02). BAV, degree of preoperative aortic insufficiency, and AVr including patch were factors predicting a higher risk of reoperation during the follow-up. Conclusion: In our experience, AVr is a safe, feasible, and efficient choice in selected patients with healed or active IE. Durability of the repair is excellent in patients with limited lesions and in patients with TAV even with patch repair. Reoperations occurred principally in patients with BAV and severe preoperative AI, in whom patch repair was performed. In those patients, we actually recommend to replace the valve in case of active endocarditis. [ABSTRACT FROM AUTHOR]

Through this study, a numerical simulation based on 3D in order to investigate the effect of crack-front shape on the stress intensity factor and fatigue crack growth behavior of center cracked aluminum plate repaired asymmetrically with bonded composite patch. Consequently, skew degree it is a significant effect on stress intensity factor (SIF) distribution along the crack front in thick panels more than in thin panels. Moreover, fatigue life was calculated using different averaged stress intensity factor of patched panel determined from uniform crack front model and skew crack front model obtained from FEM and when comparing fatigue life values obtained from the finite element model with experimental values were shown a good agreement. [ABSTRACT FROM AUTHOR]

The performance of reinforced concrete (RC) element may be deficient for a variety of causes. Correct actions should be taken to resume the performance of the deficient element to maintain the strength and serviceability of the structure. A deficient RC column element may be identified in the form of spalling of concrete cover. A patching method could be selected to recover the damaged area and, hopefully, regain the strength of the damaged RC column to its original value. This research aims to investigate the suitability of patch repair material to recover the performance of damaged RC column. The investigation is carried out by comparing the behaviour of patched RC columns with the corresponding normal RC column. The eccentric loading has been set up in this investigation to induce compression failure of the RC columns. The simulated area of damage is patched using unsaturated polyester resin mortar (UPR mortar). The results indicate that the mode of failure is not induced at the patched sections. The presence of patching causes a redistribution of stress at the patched section in such a way, so a higher stress transfer occurs in the undamaged zone and in the longitudinal reinforcements compared to those of the normal column. The capacity of the patched RC columns is only 71-92% of the normal RC column. [ABSTRACT FROM AUTHOR]

This study investigates the influence of intra-ply hybrid patches and hydrothermal aging on the indentation properties of patch repaired GFRP composites. Fabrics with various proportions of glass and Kevlar fibers were employed as the patches to achieve enhanced mechanical properties by hybridizing Kevlar and glass fibers together. Hydrothermal aging behavior of repaired composite laminates modified with water-resistant glass fibers in the outer layers was further investigated. Specimens were immersed in an environmental chamber containing seawater at temperatures of 30 (ambient), 50, and 70 °C until up to saturation. Damage mechanisms of repaired laminates were monitored using real-time acoustic emission (AE) technique. The experimental results showed that specimens repaired with 50G:50K patches offered superior performance than the virgin specimens. The hydrothermal aging effect on indentation behavior of the modified repaired specimens showed a considerable reduction in indentation properties, with higher strength retention exhibited by the repaired specimens modified with chopped glass fibers compared to the particulate fibers.

View large Download slide View large Download slide OBJECTIVES We retrospectively analysed our 20-year experience on surgical treatment of native mitral valve (MV) endocarditis in a single institution using an early and repair-oriented surgical approach. METHODS From August 1991 to December 2015, 192 consecutive patients underwent MV surgery for active endocarditis. Of these, 81% (n  = 155) had MV repair while 19% had MV replacement. In-hospital and late outcomes were analysed in the 2 groups and in the subgroups of repair with and without the use of a patch. Study end points were overall survival, MV reoperation and valve-related events. The median follow-up was 122 and 146 months in the repair and replacement groups, respectively. RESULTS Patients undergoing MV replacement were significantly older with more severe preoperative comorbidities and clinical conditions compared to patients undergoing MV repair (P  < 0.05). When the repair and replacement groups were compared, hospital mortality was 11.6% and 29.7%, respectively (P  = 0.006); at 15 years, overall survival was 57 ± 6% and 36 ± 12%, respectively (P  = 0.03); freedom from MV reoperation was 81 ± 6% and 73 ± 18%, respectively (P  = 0.46); linearized rate of recurrent endocarditis was 0.1% and 2.4%, respectively. Fifteen-year freedom from reoperation was 75.4 ± 8.6% vs 92 ± 4.5% in the patch versus no-patch repair subgroups, respectively (P  = 0.33). CONCLUSIONS Active MV endocarditis remains a life-threatening disease. In experienced centres, an early and repair-oriented surgical approach can achieve relatively high reparability rates with good long-term durability of the repair and a very low recurrence rate of endocarditis. Patients could benefit from MV repair even if patch material is necessary to repair the valve. [ABSTRACT FROM AUTHOR]

Sinus of Valsalva aneurysms are extremely rare, and usually of a congenital nature. There are few documented cases of this condition during pregnancy, which renders unclear the therapeutic options. We here report the case of a26 years old pregnant woman who was referred to our cardiac center for the evaluation of a heart murmur. The two-dimensional transthoracic echocardiography allowed quickly to establishthe diagnosis of a ruptured sinus of Valsalva aneurysm into the right ventricle. A successful surgical correction of the ruptured aneurysm was performed with patch repair.

An experimental study was conducted to evaluate the efficiency of patch repair to rehabilitate corrosion-defected reinforced concrete (RC) beam-column members when exposed to bending moments and axial forces. Ten RC beam-column members were tested under combined constant axial force and four-point transverse load up to failure. Two levels of the constant axial force were applied at either 15 kN or 30 kN (i.e., 25% or 50% of the ultimate design load of the control specimen). The accelerated corrosion process was used to get steel reinforcement corrosion inside the concrete of three levels, 0% and approximately 5% and 20%, according to Faraday’s law. The patch repair technique of cleaning or replacing corroded steel bars and replacing the damaged concrete cover with new mortar was used in this study. The experimental results of the corrosion-defected specimens showed a significant deterioration in the structural performance and the integrity by reducing ultimate capacity, stiffness, serviceability, and ductility. Additionally, the effect of increasing axial force was recorded clearly by reducing the adverse effect of corrosion, especially for defected specimens with high corrosion level. The deterioration of corrosion reinforcement could be overcome when using a patch repair technique, which restored the undamaged state and was shown clearly by using a patch repair technique with replacing corroded steel bars.

The experimental results on the effectiveness of patch repair and FRP bonded laminates to retrofit reinforced concrete beams with corrosion damage are discussed in this paper. The uncovering of the damaged concrete cover provides a more accurate assessment of the corrosion degree, as the actual mass loss of reinforcement can be better calibrated. The mass loss of the tensile reinforcement varied at approximately 7.5%–24%. The necessity of the removal of the cracked concrete substrate, treatment of corroded reinforcement and repair by patching with a polymer modified mortar is highlighted. Two different strengthening techniques are implemented, of externally bonded EBR or NSM Carbon FRP laminates, having equivalent axial rigidity. CFRP wraps were also applied for shear strengthening to replace corroded stirrups. The load-deflection curves showed that the effect of corrosion on load bearing capacity and bond between the concrete and steel was detrimental for high mass losses. A satisfactory force transfer through the old and patch repaired concrete and through repair mortar and CFRP reinforcement interface was noted. The shear strengthening not only prevented the debonding of the EB laminate at the end but also improved the bond performance between the laminate and concrete, especially for the high corroded beam. [ABSTRACT FROM AUTHOR]

Objectives The aim of this study was to report the use trends and immediate and long-term outcomes of a large cohort of patients who underwent redo surgery or transcatheter repair of paravalvular leaks (PVLs) at a tertiary referral center. Background Percutaneous treatment of mitral PVL has emerged as an alternative to surgical treatment in high-risk surgical candidates. There are limited data on the utilization trends, safety, and efficacy of both procedures in the management of mitral PVL. Methods Patients who underwent treatment of mitral PVL at the Mayo Clinic between January 1995 and December 2015 were enrolled. Utilization trends, procedural details, technical success, and in-hospital and long-term outcomes were assessed. Results Three hundred eighty-one patients underwent percutaneous (n = 195) or surgical (n = 186) treatment of mitral PVLs. The mean age was 66 ± 12 years, and 37% of patients had bioprosthetic valves. Technical success was higher in the surgical group (95.5% vs. 70.1%; p < 0.001). In-hospital major adverse events were more common after surgery (22.5% vs. 7.7%; p < 0.001). In-hospital death occurred in 3.1% and 8.6% of patients undergoing percutaneous and surgical treatment, respectively (p = 0.027). However, in a multivariate logistic regression analysis, only active endocarditis, chronic renal failure, and severe mitral annular calcifications were significant predictors of in-hospital mortality. Reintervention rates were similar (11.3% vs. 17.2% in the percutaneous and surgical groups, respectively; p = 0.10), with the majority of reinterventions in the percutaneous group occurring early because of residual leak or persistent hemolysis. After risk adjustment, there was no significant difference in long-term survival between patients who underwent surgical versus transcatheter treatment of PVLs. Conclusions In contemporary practice, patients with symptomatic mitral PVLs are best treated with an integrated team approach incorporating both surgical and percutaneous techniques. Patient selection and timing of intervention are critical to achieve optimal results. [ABSTRACT FROM AUTHOR]

Polyethylene (PE) gas pipes can be jointed together by electrofusion PE fittings, which have sockets that are fused onto the pipe. Additionally, electrofused PE patches can be used to repair defected pipes. When these pipelines are buried under the ground, they can experience sever local stresses due to the presence of pipe joints, which is superimposed on the other effects including the soil-structure interaction, traffic load, soil’s column weight, a uniform internal pressure, and thermal loads imposed by daily and/or seasonal temperature changes. The present contribution includes two cases. At first, stress variations in buried polyethylene gas pipe and its socket due to the aforementioned loading condition is estimated using finite element. The pipe is assumed to be made of PE80 material and its jointing socket material is PE100. Afterward, the effects of aforementioned thermo-mechanical loads on the stress distribution in patch repaired buried pipes are well investigated. The soil physical properties and the underground polyethylene pipe installation method are based on the American association of state highway and transportation officials and American society for testing and material standards. The computer simulation and analysis of stresses are performed through the finite element package of ANSYS Software. Stress concentrations can be observed in both components due to the presence of the socket or the repair patch. According to the results, the electrofusion sockets can be used for joining PE gas pipes even in hot climate areas. The maximum values of these stresses happen to be in the pipe. Also, the PE100 socket is more sensitive to a temperature drop. Additionally, all four studied patch arrangements show significant reinforcing effects on the defected section of the buried PE gas pipe to withstand applied loads. Meanwhile, the defected buried medium density polyethylene (MDPE) gas pipe and its saddle fused patch can resist the imposed mechanical and thermal loads of +22 °C temperature increase.

The patch-plug configuration has been widely used to repair composite structures and restore the structural integrity of damaged composites. In the present research, single-sided CFRP patch-repaired panels, with different patch-plug configurations, are prepared. This is where a circular-shaped damaged area has been removed and a CFRP patch has been adhesively-bonded onto the panel. In some cases, a CFRP plug is inserted into the hole, caused by removal of the damaged area, before the patch is applied. Such patch-repaired panels, and the pristine CFRP panel, are subjected to a low-velocity impact at an energy of 7.5 J. These impacted pristine and repaired panels are then examined using ultrasonic C-scan and optical microscopy to inspect the impact-associated permanent indentation, interlaminar and intralaminar damage. A finite element analysis (FEA) model, which significantly extends a previously validated elastic-plastic (E-P) numerical damage model, has been developed to predict the impact behaviour of the pristine CFRP panel and the various designs of patch-repaired CFRP panels. The comparison between the experimental and numerical results for all the studied cases shows the maximum deviations for the loading response and the damage area are 12% and 15%, respectively. The good agreement between the experimentally-measured impact properties and those predicted using the numerical model demonstrates that the model is a useful design tool. [Display omitted] • Pristine CFRP panels and Single-sided CFRP patch-repaired panels with and without plugs are prepared and impacted at an energy of 7.5 J; • Effects of the diameter and thickness of the patch as well as the presence of plug on the impacted behaviour of repaired composites are investigated; • Good correlation, between the experiment and simulation demonstrates that the developed numerical model is a useful design tool; • The results revealed that the patch thickness has larger effects on the impact behaviour of repaired composites compared to the patch diameter; • A plug can provide added structural integrity to a composite repair and reduce damage in the adhesive bond. [ABSTRACT FROM AUTHOR]