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Copyright of Revista Colombiana de Cirugía is the property of Asociacion Colombiana de Cirugia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Medical Journal / Medicinski Časopis is the property of Serbian Medical Society, Section Kragujevac and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Glass-fiber-reinforced plastic (GFRP) composite pipes are used extensively in high-performance applications, due to their high stiffness and strength, corrosion resistance, and thermal and chemical stability. In piping, composites showed high performance due to their long service life. In this study, glass-fiber-reinforced plastic composite pipes with [±40]3, [±45]3, [±50]3, [±55]3, [±60]3, [±65]3, and [±70]3 fiber angles and varied pipe wall thicknesses (3.78–5.1 mm) and lengths (110–660 mm) were subjected to constant hydrostatic internal pressure to obtain the pressure resistance capacity of the glass-fiber-reinforced plastic composite pipe, hoop and axial stress, longitudinal and transverse stress, total deformation, and failure modes. For model validation, the simulation of internal pressure on a composite pipe installed on the seabed was investigated and compared with previously published data. Damage analysis based on progressive damage in the finite element model was built based on Hashin damage for the composite. Shell elements were used for internal hydrostatic pressure, due to their convenience for pressure type and property predictions. The finite element results observed that the winding angles from [±40]3 to [±55]3 and pipe thickness play a vital role in improving the pressure capacity of the composite pipe. The average total deformation of all designed composite pipes was 0.37 mm. The highest pressure capacity was observed at [±55°]3 due to the diameter-to-thickness ratio effect. [ABSTRACT FROM AUTHOR]

Experimental and numerical studies of composite sandwich structures are warranted to reap the benefits of these materials when they are well designed. In the current research, new liquid thermoplastic and epoxy resins were used to fabricate four composite sandwich panels with two additional foam types and different densities in the wind turbine industry. A comprehensive comparison of three-point bending test results was made. Finite-element-based simulations using the ABAQUS program with Hashin's damage criterion were conducted to examine the failure behavior of the GFRP sandwich composites. The flexural behavior of the glass-fiber-reinforced plastic (GFRP) sandwich panels was investigated and compared with the experiments. The results show that the GF/PVC/Elium composite panel gives the highest load absorption, flexural strength, flexural modulus, core shear ultimate strength, and facing stress due to effect of the core foam and resin types. For the PVC foam core sandwich panel, using thermoplastic resin increased the flexural strength by 18% compared to that of the epoxy resin. The simulation results show excellent agreement between the finite-element-predicted failure loads and the experimental results. [ABSTRACT FROM AUTHOR]

Composite sandwich structures have been used in high performance applications such as wind turbine blades, due to their unique lightweight structure and superior mechanical properties. In the current study, a new liquid thermoplastic and thermoset resin were used to fabricate four different composite sandwich panels with two various foam types and densities. Composites made with epoxy resin are presented to comprehensively compare the mechanical properties of sandwich structures to elium resin. In the case of the mechanical properties and due to a new liquid thermoplastic resin, extensive comparisons of three-point bending, climbing drum peel, and flatwise tensile strength were investigated and compared with each other. The flexural and flatwise strength of sandwich composite increased by 53% and 75%, respectively, when using Elium resin. Then, the highest value was shown in the GF/PVC/ELIUM structure. The results revealed that Elium resin could be excellent in the case of mechanical properties to replace traditional resins to fabricate various composite structures and manage the challenge of recyclable composites. Elium resin can replace thermoset-based resins for the manufacturing of laminates and composites that are fully recyclable at room temperature with comparable mechanical properties. [ABSTRACT FROM AUTHOR]

Background Esophageal achalasia is an esophageal-motility disorder of unknown etiology that results in impaired relaxation of the lower esophageal sphincter and loss of esophageal peristalsis. Achalasia can be primary (idiopathic) or secondary. In secondary achalasia, the cause for the degeneration of esophageal nerve fibers is known. Pathophysiologically, achalasia is caused by loss of inhibitory ganglion cells in the myenteric plexus. Several studies have attempted to explore initiating agents that may cause the disease such as viral infection, other environmental factors, autoimmunity, and genetic factors. However, the exact pathogenesis of primary achalasia is still not known. Aim The aim of the study is to assess esophageal dilatation before surgery as a risk factor for esophageal mucosal injuries during laparoscopic Heller's cardiomyotomy. Patients and methods This prospective study was performed on a total of 20 patients who diagnosed with esophageal achalasia undergoing Heller's cardiomyotomy and willing to participate in the study at Tertiary Care Hospital at Ain Shams University Hospitals from July 2019 to June 2021 with inclusion and exclusion criteria. Results There was no statistically significant difference among the studied groups regarding type of achalasia and preoperative lower esophageal sphincter pressure. There was significant higher operative time among previous-dilatation group than the no-previous-dilatation group with no statistically significant difference among the studied groups regarding postoperative wound infection, intraoperative bleeding, and postoperative hospital stay. There was no statistically significant difference among the studied groups regarding postoperative-reflux esophagitis and perforation. Our results revealed a highly significant difference between the preoperative and postoperative Eckardt scores among the same group with P value of 0.007 in the no-previous-dilatation group and P value of 0.003 in the previous-dilatation group, while there was no statistically significant difference found between the studied groups regarding preoperative and postoperative Eckardt scores. Conclusion As evident from the study, previous esophageal dilatation is not a risk factor for mucosal injury during laparoscopic Heller myotomy for achalasia. Laparoscopic Heller's cardiomyotomy achieved symptomatic improvement in all patients, regardless of prior pneumatic balloon dilation, and preoperative pneumatic balloon dilation did not affect the incidence of residual symptoms, necessity of additional postoperative treatments, occurrence of symptomatic gastroesophageal reflux disease, or intraoperative mucosal perforation. [ABSTRACT FROM AUTHOR]

The article titled "Mechanical Properties Study on Sandwich Composites of Glass Fiber Reinforced Plastics (GFRP) Using Liquid Thermoplastic Resin, Elium®: Preliminary Experiments" has been retracted by the Coatings Editorial Office. Concerns were raised about the ownership of the data presented in the publication, and an investigation confirmed that the authors did not have permission from the University of Nottingham (Ningbo, China) to publish the data. As a result, the article has been retracted in accordance with MDPI's retraction policy and the Committee on Publication Ethics retraction guidelines. It is important to note that the authors did not agree with the retraction. [Extracted from the article]

The article provides an overview of biocomposite application in the automotives via a documentation of their history, chronology and progressive steps taken to break into the production lines of a number of key auto makers. It offers a detailed analysis of the key factors that have motivated the research and subsequent adoption of biocomposites; taking a peek at the advantages, disadvantages, and challenges experienced in the process. Auto makers and parts suppliers that have been a force behind this campaign, have also been accorded a fair share in the article. Future projection of role of these materials in the industry; with the ideas well dressed in form of bio concept cars caps up the paper. Automotive refers to; passenger cars, sport utility vehicles, vans, trucks, buses, and recreational vehicles. POLYM. COMPOS., 38:2553-2569, 2017. © 2016 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

Finite element analysis and experimental studies are presented on in-plane tensile and compressive properties under quasi-static loading for two types of hybrid composites made by using unidirectional T620S carbon and E-glass fabrics in a common matrix, epoxy resin. Results are also generated for plain T620S carbon/epoxy and plain E-glass/epoxy composite laminates. Quantitative data for tensile and compressive properties are presented. It is observed that for hybrid composites, placing carbon and glass fiber parts alternately in every layer (intralayer configuration) gives higher tensile and compressive strengths. Tensile failure strain is higher for intralayer compared to interlayer hybrid configuration. [ABSTRACT FROM AUTHOR]

The impact response to twill weave carbon fabric/epoxy composite laminate structure has been investigated by employing two types of the stacking sequences of composite laminate structure to low-velocity impact loadings by using a Drop-Weight Machine (CEAST 9350 drop tower). An engine hood is the intended application for the composites. The air-coupled ultrasonic C-scan technique (NAUT21) has been selected in order to characterize impact damage size, delamination, flaw detection, and damage in composite laminate structures. The effect of increasing impact energy was illustrated with both types of the stacking sequences of the composite laminate structures until complete perforation of specimens at 25 J due to degradation of mechanical properties of composite laminates. The failure processes of damaged specimens for different three impact energies (5 J, 15 J, and 25 J) were being evaluated comparing load–displacement curves and images of damaged samples were taken from both impacted and nonimpacted sides through C-scan. The performance index and absorbed energy of the tested structures were investigated. The primary damage modes were found to be fiber fracture, delamination, and matrix cracks. [ABSTRACT FROM AUTHOR]

In this study, investigation has been made on the impact response of twill weave carbon fabric/epoxy foam sandwich composites by subjecting two types of stacking sequences of a sandwich composite structure, SC1 and SC2 to quasi-static indentation and low velocity impact loading. SC1 and SC2 had a sequence of [0/90, ±45, Core, 0/90, ±45], [0/90, ±45, 0/90, ±45, 0/90, Core, 0/90, 0/90, 0/90, 0/90], respectively. This work was done by use of material testing system and an instrumented Drop-Weight Machine (CEAST 9350 drop tower). Foam sandwich composite structures are mainly used in making an Engine Hood. The analysis was done with increase of impact energy on both types of stacking sequences, until complete perforation of the specimens at 25 Joule impact energy occurs. The failure processes of the damaged specimens under the three different impact energies (5 J, 15 J, and 25 J) were evaluated by comparing load-displacement curves. Images of damaged samples were taken from both impacted side and non-impacted side and compared for all impact energies. Cross-sections of damaged specimens were also inspected visually and discussed. The load-displacement curves were obtained to characterize the failure mechanisms in the face sheets and core. Failure modes were also studied by sectioning the samples at the impact location and observed under an optical microscope. The primary damage mode was found due to the fiber fracture, delamination, matrix crack, and foam crack. [ABSTRACT FROM AUTHOR]

A brief review of research progress in dynamic and static response of composites structures subjected to low velocity impact and quasi-static loads has been presented. This review paper focused on experimental and numerical studies done by many authors recently for the low-velocity impact damage. For simulations of drop weight low-velocity impact damage, many researchers has used software programs in order to predict the failure modes in composite structures such as ABAQUS/Explicit, LS-Dyna, and MSC. Dytran, DYNA3D, and 3DIMPACT have been commonly used. The impact response of high performance fiber composites is reviewed. An attempt is made to collect the work published in the literature and to identify the fundamental parameters determining the impact resistance of composite materials and their properties. The review concludes with detailed discussions on the damage mechanisms and failure criteria for composite structures subjected to impact loads. [ABSTRACT FROM AUTHOR]

The amblyceran and ischnoceran lice removed from the Indian Peafowl (Pavo cristatus L.) collected at the Riyadh bird market, and other specimens available in the King Saud University Museum of Arthropods, Kingdom of Saudi Arabia, were identified. Amyrsidea minuta Emerson, a new country record, and Goniodes dissimilis Denny were found infesting the Indian Peafowl in Saudi Arabia. Goniodes dissimilis is recorded for the first time from this bird species, along with Menacanthus stramineus (Nitzsch), the wellknown chicken body louse. All previous records of the 12 species of chewing louse reported from the Indian Peafowl are reviewed. An identification key for the 13 species is given with taxonomic notes. Additionally, a new photo-editing technique for chewing louse images is noted. [ABSTRACT FROM AUTHOR]

Thirty-three species of mosquitoes have been reported from the Kingdom of Saudi Arabia. Several of these mosquitoes, Anopheles gambiae Giles s.l., Anopheles stephensi Liston, Culex pipiens Linnaeus, Culex quinquefasciatus Say, Culex tritaeniorhynchus Giles, Stegomyia aegypti (Linnaeus) and Aedimorphus vexans arabiensis (Patton) are known vectors of human and animal diseases. In this study, the cuticular hydrocarbon profiles of eight mosquito species using gas chromatography-mass spectrometry were analyzed. Wild collected fourth-instar larvae were reared, and single, newly emerged, unfed adult females were used for the analysis. A total of 146-160 peaks were detected from the cuticular extracts by gas chromatography. Repeated analysis of variance (ANOVA) and Tukey HSD Post Hoc test was used to test for quantitative differences in relative hydrocarbon quantity. In addition, a linear regression model was applied using Enter method to determine the diagnostic peaks for the eight mosquito specimens. The ANOVA test indicated that relative peaks were significant ( P < 0.05) when selected pairs of peaks were compared. Also, seven compounds showed qualitative differences among the five mosquito vectors tested. The classes of constituents present were n-alkanes, monomethylalkanes, dimethylalkanes, trimethylalkanes, alkenes, branched aromatic hydrocarbons, aldehydes and esters. These compounds have a carbon chain length ranging from 8 to 18 carbons. The most abundant compound in all adult mosquito specimens was n-hexylacrylate [retention time (RT) 6.73 min], which was not detected in Cx. pipiens. In Cx. pipiens, the most abundant peak was benzaldehyde (RT 2.98 min). Gas chromatography-mass spectrometry is a suitable method to identify adult mosquitoes, especially from focal areas of public health concern such as Jazan Province, Saudi Arabia. This method allows a wide range of adult collected material to be identified with high accuracy. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Background: The mosquito, Culex tritaeniorhynchus Giles is a prevalent and confirmed Rift Valley Fever virus (RVFV) vector. This vector, in association with Aedimorphus arabiensis (Patton), was responsible for causing the outbreak of 2000 in Jazan Province, Saudi Arabia. Methodology/Principal Findings: Larval occurrence records and a total of 19 bioclimatic and three topographic layers imported from Worldclim Database were used to predict the larval suitable breeding habitats for this vector in Jazan Province using ArcGIS ver.10 and MaxEnt modeling program. Also, a supervised land cover classification from SPOT5 imagery was developed to assess the land cover distribution within the suitable predicted habitats. Eleven bioclimatic and slope attributes were found to be the significant predictors for this larval suitable breeding habitat. Precipitation and temperature were strong predictors of mosquito distribution. Among six land cover classes, the linear regression model (LM) indicated wet muddy substrate is significantly associated with high-very high suitable predicted habitats (R2 = 73.7%, P<0.05). Also, LM indicated that total dissolved salts (TDS) was a significant contributor (R2 = 23.9%, P<0.01) in determining mosquito larval abundance. Conclusion/Significance: This model is a first step in understanding the spatial distribution of Cx. tritaeniorhynchus and consequently the risk of RVFV in Saudi Arabia and to assist in planning effective mosquito surveillance and control programs by public health personnel and researchers. [ABSTRACT FROM AUTHOR]

In response to the high demand for light automotive, manufacturers are showing a vital interest in replacing heavy metallic components with composite materials that exhibit unparalleled strength-to-weight ratios and excellent properties. Unidirectional carbon/epoxy prepreg was suitable for automotive applications such as the front part of the vehicle (hood) due to its excellent crash performance. In this study, UD carbon/epoxy prepreg with 70% and 30% volume fraction of reinforcement and resin, respectively, was used to fabricate the composite laminates. The responses of different three stacking sequences of automotive composite laminates to low-velocity impact damage and flexural and crash performance properties were investigated. Three-point bending and drop-weight impact tests were carried out to determine the flexural modulus, strength, and impact damage behavior of selected materials. Optical microscopy analysis was used to identify the failure modes in the composites. Scanning electron microscopy (SEM) and C-scan non-destructive methods were utilized to explore the fractures in the composites after impact tests. Moreover, the performance index and absorbed energy of the tested structures were studied. The results showed that the flexural strength and modulus of automotive composite laminates strongly depended on the stacking sequence. The highest crash resistance was noticed in the laminate with a stacking sequence of [[0, 90, 45, −45]2, 0, 90]S. Therefore, the fabrication of a composite laminate structure enhanced by selected stacking sequences is an excellent way to improve the crash performance properties of automotive composite structures. [ABSTRACT FROM AUTHOR]