Different Types Of Meshes Research Articles

Elective complex ventral hernia repair in contaminated fields: A propensity score–matched analysis of long-term quality of life and outcomes between different prostheses

BackgroundRandomized studies have endorsed nonabsorbable prosthetics for contaminated ventral hernia surgery, yet the broader applicability and impact on patient-reported outcomes are still questioned. Here, we evaluated the long-term outcomes of elective contaminated ventral hernia repairs (based on Centers of Disease Control and Prevention [CDC] wound classification) using real-world data from a multicenter US cohort, focusing on quality of life and postoperative pain. MethodsThe Abdominal Core Health Quality Collaborative database was queried for patients undergoing elective contaminated (CDC class II–IV) ventral hernia repair (2013–2023). After propensity matching, we compared long-term differences in patient-reported quality of life and pain scores (by HerQLes and PROMIS questionnaires) among those who underwent repair with nonabsorbable, absorbable synthetic, and biologic mesh. ResultsA total of 1,073 patients were included, of whom 920 (86%), 56 (5%), and 97 (9%) underwent repair with nonabsorbable, absorbable synthetic, and biologic mesh, respectively. Among them, the median age was 62 years (interquartile range [IQR] 53–70), and 523 (49%) were male. The median length and width of the defect were 20 cm (IQR 12–25) and 13 cm (IQR 8–16), respectively. A transversus abdominis release was performed in 716 patients (67% of all cases). In most cases, the mesh was positioned in the retro-rectus (85%) and/or the preperitoneal space (45%). Before and after propensity matching (n = 185), the change from baseline in HerQLes and PROMIS scores at 6 months and at 1, 3, 5, and 6 years was comparable between different types of mesh. Lastly, there were no differences in readmission, surgical site infection, or surgical site occurrence at 30 days. Recurrence at 1 year was also comparable among groups. ConclusionIn the long term, there were no differences in quality of life or pain scores with nonabsorbable, absorbable synthetic, or biologic mesh for elective ventral hernia repair in contaminated fields.

Influence of Some Factors on Propolis Dilution by Honey Bees

Propolis is a sticky resinous substance collected from buds, leaves, stems of wild plants and processed by bees. Currently, bee behaviour during the collection of propolis, its botanical origin and sources of production have been studied. The process of propolis accumulation in bee nests and the factors influencing the intensity and productivity of bee colonies need to be further studied, which will allow to control the propolis productivity of bees in the future. To better understand the behavior of bees when liquefying propolis with enzymes from the mandibular glands, we conducted studies using specially designed collectors. Three different types of mesh were used in the collectors: ethylene vinyl acetate (EVA), polyethylene, and nylon. All three types of meshes had different hole diameters. As a result of the study, we determined the diameter of propolis droplets formed in all collectors, deviations from roundness, and the distance at which the droplets fly away from the edge of the glass substrates. We conclude that the type of mesh materials does not influence the behavior of bees in liquefying propolis. The size of the mesh holes affects the distance from the edge of the glass substrate to the centre of the propolis drops.

Experimental analysis on fog harvesting by means of bi- and three-dimensional meshes: a laboratory study

Nowadays the lack of reliable water sources has become a significant problem, particularly in dry regions. In this context, fog harvesting appears to be a very promising solution to address this issue. Therefore, in recent years, a new device named ‘fog water collector’, composed of a mesh and a supporting structure, has been introduced. So far, the most used mesh for this type of application has been the Raschel mesh, but various researches are trying to improve the efficiency of fog water collectors by investigating different types of meshes. This paper aims at studying the fog collection efficiency of some alternative meshes available on the market, differing in material, geometry, filament shape, and overall thickness, under controlled laboratory conditions. The results allowed to group the meshes into two sets, namely the two-dimensional ones, including the Raschel mesh, which showed an average collection efficiency in the range 1.6–3.1%, and the three-dimensional ones, with an average collection efficiency in the range 4.9–7.7%, thus emerging as the most efficient. Moreover, the best values for the shading coefficient resulted to be around 50–80%, while the optimal air permeability was in the range 5000–10000 L/(m2⋅s) under 80 Pa pressure difference.

Influence of meshes on mechanical performance and stiffness of single-lap adhesive bonded composite joints

The present work focused on improving the tensile, three-point bending strength, and natural frequency of single-lap adhesive bonded composite joints (SLABCJs) by impregnating two different types of meshes given as stainless-steel 304 and knitted-fabric mesh in brittle adhesive. Hand-layup method was used to fabricate the laminate used for SLABCJs. It is concluded that adhesive-impregnated stainless-steel and knitted meshes improved the load-carrying capacity by 25.06%, 18.73% under tensile test, 30%, 10.1% under three-point bending, and 18.6%, 12.62% stiffness of the SLABCJs, compared to neat adhesive. Overall, adhesive-impregnated stainless-steel mesh joint enhanced the strength and delayed the sudden failure of the joints.

Numerical investigation on performance of a solar chimney power plant with different absorber configurations

AbstractA solar tower system is a nonpolluting solar thermal power plant that utilizes a combination of a wind turbine and generator to convert thermal energy generated from a solar collector into electrical energy. The study focuses on a system comprising a solar collector that transforms solar energy into thermal energy, a chimney that converts thermal energy into kinetic energy, and a wind turbine that further converts kinetic energy into electrical energy. The system's performance is evaluated through the implementation of a numerical model, which is validated by comparing it with experimental data. Four different types of meshes are tested to determine the most suitable mesh for the system. The discrete ordinate radiation model is used to solve the radiative transfer equation, and the RNG k‐𝜀 turbulence model is implemented to calculate turbulence. In a subsequent study, the effect of absorber configuration on the system's performance is investigated. Three different absorber configurations—sinusoidal, square, and triangular—are proposed, and the numerical results showed that the system's performance is affected by the absorber configuration. The velocity in the chimney inlet increases for all proposed configurations compared to the standard configuration, with the triangular configuration showing the highest velocity increase. Additionally, the newly proposed configurations enhance the thermal efficiency of the system, leading to a thermal efficiency of 12.18%, 12.2%, and 13.65% for the sinusoidal, triangular, and square configurations, respectively. Overall, the solar tower system demonstrates its potential as a clean and efficient source of electrical power.

TURBULENCE MODELING OF SHOCK BOUNDARY LAYER INTERACTION IN HYPERSONIC FLOW

Computational fluid dynamics (CFD) simulations of shockwave turbulent boundary layer interactions using different turbulence modeling including Reynolds-averaged Navier-Stokes (RANS) with different closures (Menter's <i>k</i>-ω-SST, and Spalart-Allmaras) have been investigated. The objective of the study is to assess the capability of current CFD codes, Ansys Fluent and STARCCM, to model hypersonic flow over a large hollow cylinder flare for Mach 6 with Re<sub>∞</sub> = 5.33 × 10<sup>7</sup> The results of heat transfer and pressure data over the surface are presented for two-dimensional, axisymmetric, and three-dimensional RANS models using experimental data of LENS II high Reynolds number shock/Ludweig tunnel at the CUBRC center. Effects of properties of real gas, perfect gas, and different types of mesh have been considered for the assessment.

OGBN O05 Short term outcomes after mesh hiatal hernioplasty versus suture cruroplasty in hiatus hernia repair at a busy District General Hospital

Abstract Background Laparoscopic cruroplasty for giant hiatus hernias utilizing non-absorbable sutures, has been demonstrated to be safe with good symptomatic relief. However, recurrence rates as high as 42% have been reported. Hiatoplasty using synthetic mesh was introduced to reduce recurrence. However, there are concerns due to complications, most notably oesophageal erosion. Due to the lack of high-quality comparative data between different types of mesh for hiatus hernia repairs, there is little evidence to guide use of mesh. We aimed to assess outcomes comparing suture cruroplasty (SC) with mesh hiatus hernioplasty (MHH) after HH repair in our unit at a busy DGH. Methods We retrospectively collected data of consecutive patients undergoing hiatus hernia repair between January 2016 and December 2021. Data was obtained from electronic patient records form hospital system. Primary outcomes assessed were recurrence and re-operation rates at follow up. Secondary outcomes assessed were peri-operative morbidity. We used PTFE coated composite (dual gore) mesh for MHH. Data were analysed using the two-tailed t-test for continuous data and χ2 or Fishers exact tests for categorical data. Level of statistical significance was set at p value of <0.05. Results 145 patients (SC= 98, MHH= 47) underwent hiatus hernia repair. Indications were paraesophageal (Type II-IV) HH in 58.62%, and large Type I HH in 41.38%. Conversion rate was 0.67%. There was no significant difference in post –operative morbidity. An outcome without postoperative complications was achieved in 77.24% of cases overall. After a mean follow-up of 17 months, hernia recurrence (10.2% versus 14.89%, p=0.42) and re-operation rates (5.1% versus 8.51%, p=0.47) were not significantly different. There were no mesh erosions. Overall, 132patients (91.03%) had relief from symptoms, 115 (79.31%) were able to stop GORD medications. Conclusions Suture cruroplasty and mesh hernioplasty produce comparable results with respect to recurrence and re-operation rates. Recurrence rates after repair are low, and are asymptomatic in most cases. A long-term follow up will enable to identify any significant future impact of method or modality of repair on patient outcome.

Topological Relationship‐Based Flow Direction Modeling: Stream Burning and Depression Filling

AbstractFlow direction modeling consists of (a) an accurate representation of the river network and (b) digital elevation model (DEM) processing to preserve characteristics with hydrological significance. In part 1 of our study, we presented a mesh‐independent approach to representing river networks on different types of meshes. This follow‐up part 2 study presents a novel DEM processing approach for flow direction modeling. This approach consists of (a) a topological relationship‐based hybrid breaching‐filling method to conduct stream burning for the river network and (b) a modified depression removal method for rivers and hillslopes. Our methods reduce modifications to surface elevations and provide a robust two‐step procedure to remove local depressions in DEM. They are mesh‐independent and can be applied to both structured and unstructured meshes. We applied our new methods with different model configurations to the Susquehanna River Basin. The results show that topological relationship‐based stream burning and depression‐filling methods can reproduce the correct river networks, providing high‐quality flow direction and other characteristics for hydrologic and Earth system models.

COMPUTATION OF FLOW ABOUT AIRFOILS – COMPARISON OF PANEL METHOD AND CFD METHOD

The aerodynamic study of an airfoil is fundamental to analyze the behavior and define geometrical characteristics of a wing for prescribed flight conditions. Based on analyzes and simulations we are able to define the variables for aerodynamic design of an aircraft. The unmanned aerial vehicle (UAV) designed for SAE Aerodesign competition use high lift airfoils for low Reynolds number flow. The viscous or inviscid flow about airfoils can be computed using different methodologies, such as panel method or finite volume method. The main objective of this work is to compute and compare the lift and drag coefficients as well as pressure distributions in the contour of airfoils calculating the inviscid and viscous flow, using a panel method and a finite volume method. For the numerical analysis, high lift airfoils of families NACA 4, EPPLER, GOE, CH and SELIG were selected. These airfoils have very good aerodynamic efficiency with high ratio between the lift and drag coefficients. These profiles are highlighted by its high mean-line curvature and are used at low speeds, being indicated for the SAE Aerodesign competition aircrafts. The criterion used to choose the airfoil was the highest lift coefficient generated in relation to its maximum stall angle, at a number of Reynolds of cruising flight speed, that is close to the transition from laminar boundary layer to turbulent boundary layer. The panel method analysis was performed using the XFRL5 software that uses XFOIL as source code. In the finite volume method, the Fluent code of ANSYS was used. Different types of meshes, structured and unstructured, are compared and quality parameters of mesh cells are analyzed and presented. The pressure distributions and the lift and drag coefficient curves, for the selected aerodynamic profile, calculated using panel method and finite volume method, are also presented and compared.

Potential of waste woven polypropylene fiber and textile mesh for production of gypsum-based composite

The huge production of woven polypropylene bags has led to an increase generation of plastic waste. The recycling of waste woven polypropylene bags and textiles in construction applications can be a viable option. Therefore, an attempt has been made to utilize the woven polypropylene fibers and textiles in the production of gypsum-based composite false ceiling tile for an economical and sustainable construction product. In the current research work, different water-to-powder ratios (0.6 %, 0.7 %, 0.8 %, 0.9 %) and fiber contents (0.25 %, 0.35 %, 0.45 %, 0.55 %) in the gypsum-based composite were prepared. Flexural plates with different thicknesses (18, 15, 12, and 9 mm) incorporating different recycling fibers and reinforced with different types of meshes were manufactured to produce sustainable gypsum-based plates. The physical properties, compressive and flexural strength properties of the fiber-reinforced gypsum-based composite were also evaluated. The textile and woven polypropylene fiber mesh reinforced gypsum false ceiling plates were compared with the control specimen. The results revealed that the density of gypsum-based composite decreased up to 26 % with the increase in the proportion of waste fiber contents. The compressive and flexural strength of gypsum-based composites exhibited a decrease with an increase in fiber contents and water-to-powder ratio. However, all the specimens satisfied the acceptable limit of 1 MPa and 2 MPa, respectively, according to BS EN 14246. The bending strength of all the plates incorporating different fiber content and thicknesses satisfied the minimum specified flexural strength criteria according to BS EN 14246. Moreover, the plates with different thicknesses and fiber contents also satisfied the minimum specified flexural criteria except for the plate with a thickness of 9 mm. However, all the plates with varying thicknesses and reinforced mesh have also satisfied the minimum load criteria specified by BS EN 14246. Thus, it can be envisioned that the woven polypropylene fibers and textiles can be effectively utilized to produce sustainable gypsum-based composite leading to reduce waste generation.

Reconstruction following full-thickness excision of abdominal wall tumors: A prospective observational study conducted in a tertiary care Government Hospital in Eastern India

Background: Reconstruction of abdominal wall defects following full-thickness excision of large tumors (primary or metastatic) has always been a challenge for the treating surgeon. A number of reconstructive techniques have been described in the literature, including different types of meshes, flaps, and component separation techniques (anterior and amp; posterior), with varying results. We conducted a prospective observational study of our three-layer technique of abdominal wall closure at Medical College Hospital, Kolkata, to assess the long-time success of the procedure, especially in terms of hernia rates. Aims and Objectives: Reconstruction of abdominal wall defects following full-thickness excision of large tumors (primary or metastatic) has challenged surgeons for long, with several reconstructive techniques being described, with varying results. We conducted a prospective observational study of our three-layer technique of abdominal wall closure at Medical College Hospital, Kolkata, to assess the long-time success of our procedure, especially in terms of hernia rates. Materials and Methods: Thirteen patients with abdominal wall primary and isolated metastatic tumors were included from January 2017 to January 2022 with follow-up period from 8 to 60 months. Tumors were dermatofibrosarcoma protuberans, sarcomas, desmoid tumors, and two abdominal wall metastases. All patients in our study underwent computed tomography scan, core needle biopsy, and immunohistochemistry for better surgical planning. Results: Eight patients were male and five were female with mean age of 39 years and mean defect size of 10 cm. Polypropylene mesh was used, size varying from 15×15 to 30×30 cm with average operative time of 210 min. Post-operative superficial wound infection in 2 (15%), partial flap necrosis in 1 (7.6%), and tumor recurrence in one patient (7.6%) were seen. Conclusion: For closure of such large abdominal wall defects, our three-layer reconstructive technique has shown good results in terms of zero hernia rates. We recommend our method of closure, where affordability of biological meshes, availability of expensive meshes, accessibility to plastic and reconstructive surgeons or non-acquaintance with complex closure techniques are present.

Experimental Investigation on Flexural Behaviour of Ferrocement Laminates Using Different Forms of Meshes

Abstract: The present study describes the results of testing ferrocement panels reinforced with of different types of meshes. The main objective of the study was to investigate the effect of different types of meshes as reinforcement in thin mortar specimen and select the best suitable mesh for further work. Types of meshes were used expanded metal mesh, galvanized woven mesh and welded mesh has a diameter of 1.58 mm. Size of openings are 20x35 mm, 10x10 mm and 15x15 mm. Panels of a size of 560x150x35 mm were reinforced with three layers of wire mesh. Panels were casted with mortar of mix proportion 1:2 and water cement ratio 0.40. The four specimens were tested under four-point loading system on universal testing machine after curing period of 7 days and eight specimens after curing period of 28 days. Test results shows that the flexural strength of the specimen with welded mesh exhibits greater flexural strength than other two types of meshes.

MoM Solution of Broadband Radiation and Scattering Problems Based on Entire-Domain Hyperbasis Functions Approach

A new method of moments (MoM)-based approach is proposed to efficiently solve broadband radiation and scattering problems on triangulated, quadrilateral, and mixed mesh geometries. This approach is based on expanding the total current on a conducting body at any desired frequency in terms of entire-domain hyperbasis functions (HBFs), calculated at only one frequency. These HBFs must be found as eigenfunctions of the generalized eigenvalue equation (GEE), defined at that frequency. The developed approach is validated by comparing results with those obtained by direct MoM for different types of mesh. Finally, it is demonstrated for solving practical antenna problems.

Comment on "Sutured Versus Mesh-augmented Hiatus Hernia Repair: A Systematic Review and Meta-analysis of Randomized Controlled Trials".

Comment on "Sutured Versus Mesh-augmented Hiatus Hernia Repair: A Systematic Review and Meta-analysis of Randomized Controlled Trials".

THE EVALUATION OF MESH CHARACTERISTICS OF THE CAR MODELING AND SIMULATION USING CFD ANALYSIS

In a car CFD simulation, different types of mesh could change the output of the simulation and may differ with the results gathered using wind tunnel experiment. Therefore, adjusting and getting the best mesh for the simulated car model is an important step in a CFD simulation. This study investigated the effect of the different number of elements on a saloon car CFD simulation. The elements themselves have a similar mesh quality, but the number of elements ranged from just over a couple hundred thousand to over 3 million elements. The results show that with this number of mesh, the accuracy did not increase significantly even though the elements multiplied in amount. It is suggested that simulation with higher number of elements might be the best choice if the facilities are supportive. It is also shown that the lower number of elements could be an alternative because the accuracy is sufficient.

Conservative multilevel discrete unified gas kinetic scheme for modeling multiphase flows with large density ratios

A novel multilevel discrete unified gas kinetic scheme (MDUGKS) is proposed to efficiently model multiphase flows with large density ratios. By constructing the kinetic flux with a mutable time interval depending on the local mesh spacing, the MDUGKS overcomes the stability problems encountered by the standard DUGKS when operating with the multilevel mesh. With the interpolation of macroscopic variables and mesoscopic distributions handled separately, the moments of distribution functions are maintained consistent with the conservative flow variables. Two kinetic equations corresponding to the conservative Allen–Cahn equation and the hydrodynamic equation are individually solved by the MDUGKS, and six benchmark problems have been conducted to evaluate its performance. Numerical solutions in steady cases produced by the MDUGKS are in well accordance with the theoretical predictions. A limiting density ratio of 109 is achieved in the quiescent droplet. The dynamic processes in unsteady cases anticipated by the MDUGKS agree well with the reference predictions. Comparative results also demonstrate that the MDUGKS behaves consistently with different types of meshes. With the employment of the adaptive multilevel mesh, 80% improvement in computational efficiency could be achieved compared with the uniform mesh. Considering the kinetic nature and the high efficiency, the MDUGKS offers a powerful tool for presenting meaningful insight into understanding the realistic multiphase systems at the mesoscopic scale.

Comparison of Hybrid Versus Synthetic Mesh in Robotic Rives-Stoppa Ventral Hernia Repair.

To estimate the average treatment effect on the treated (ATT) and to assess the clinical outcomes in two different types of mesh in robotic Rives-Stoppa (rRS) ventral hernia repair (VHR). A retrospective analysis of a robotic VHR database between February 1, 2013 and May 31, 2022. Patients who underwent a rRS VHR were included in this study and separated into two groups depending on the mesh used: SynecorTM Preperitoneal Biomaterial (SynecorTM Pre) and Bard™ Soft. Through propensity score and inverse-probability-treatment-weighting, the ATT was estimated for two scenarios; the first with the treated target having used the SynecorTM Pre, the second having used the Bard™ Soft mesh. Adjusted linear regression models, including lingering imbalanced variables, were used for both the primary outcome of the Comprehensive Complication Index (CCI®), and the secondary outcome of the hospital cost. A total of 186 patients who underwent rRS were separated into the two groups (SynecorTM Pre mesh, n = 85; Bard™ Soft mesh, n = 101). Adjusted linear regression models for the CCI showed no statistical difference between both groups (p > 0.05), whereas ATT on hospital cost was significantly higher (p < 0.001) in the SynecorTM Pre group in both scenarios [(95% confidence interval) = 3882 (2352, 5413) and -5185 (-8213, -2157), respectively]. Both mesh materials provided excellent outcomes with no difference in complications or recurrence rates. However, hospital cost was found to be higher in the hybrid mesh group. Long-term follow-up is needed to fully assess the performance of both mesh types in rRS.

The use of meshes in male groin hernia repairs

The use of a mesh is standard practice in the surgical repair of groin hernias. No one type of mesh or surgical technique appears to be superior to another. Here the authors discuss the evolution of groin hernia repair, the different types of mesh, as well as the investigation and management of complications that can occur, albeit in a minority of patients.

Low tunnels with shading meshes: An alternative for the management of insect pests in kale cultivation

Kale (Brassica oleracea L. var. acephala) is one of the most cultivated leafy vegetables in Brazil. Abiotic and biotic factors can damage kale crops, reducing production and quality and making it impossible to market the product. Thus, because consumers demand sustainable production of food, the objective of this study was to evaluate the production of kale and the damage caused by pests of hybrid kale grown in different seasons and under different types of mesh. Two growing seasons, six growing environments and two kale hybrids were evaluated. The parameters evaluated were yield as measured by the total number of leaves, marketable leaves, and damaged leaves. The settlement of Myzus persicae and the damage caused by Plutella xylostella, Hellula undalis and Diabrotica speciosa were quantified. During the dry season, there was a lower yield per plant, but there was greater commercial production due to lower levels of insect infestation on plants. The use of nonwoven shade mesh reduced the damage from P. xylostella and D. speciosa on plants grown during the rainy season and reduced M. persicae during the dry season. However, cultivation under the protection of the organza fabric provided more effective protection against P. xylostella and D. speciosa, resulting in greater production of kale leaves.

Evaluation of intra-abdominal adhesion formation after laparoscopic ventral hernia repair with composite mesh using abdominal ultrasound: a prospective observational study

Background: Laparoscopic ventral hernia repair has revolutionized treatment of ventral hernia by offering shorter recovery time, decreased pain, reduced wound complications and lower recurrence rates as compared to conventional open hernia repair. But intra-abdominal mesh placement is associated with a high risk of complications including adhesions, bowel obstruction and fistula formation. Many different types of meshes with adhesion barriers have been developed to overcome these problems. This prospective observational study evaluated the outcomes of laparoscopic repair of ventral hernias in terms of Intra-abdominal adhesion formation with composite mesh using ultrasound.Methods: The study was conducted from August 2017 to February 2019. All patients underwent standard laparoscopic ventral hernias repair using composite mesh secured with tackers. Omentum was interposed between the mesh and underlying bowel. At a mean follow-up of one year, all patients were subjected to ultrasound examination using visceral slide technique to detect Intra-abdominal adhesions.Results: Our study included 50 patients with a mean age of 43 years (range 26-59 years) and mean body mass index of 29.07±2.35 kg/m2 (range, 24-33 kg/m2). Mean fascial defect size of hernia was 13.4±3.77 cm2 (range12-16 cm2). There were no mesh-related complications and recurrence during the follow-up period of 1 year.Conclusions: Laparoscopic ventral hernia repair using composite mesh seems to be a promising technique for treating ventral hernias. However, longer follow-up periods are needed to confirm effectiveness and safety of the composite mesh.