Longitudinal Fibers Research Articles

Bidirectional Single Longitudinal Mode Er-Doped Fiber Ring Laser Using a Bandpass Filter and Cascaded Fiber Ring Filter

Bidirectional single longitudinal mode fiber ring laser have advantages and potential in optical sensing, especially angular velocity sensing. The current methods for implementing bidirectional single longitudinal mode fiber ring laser cannot ensure complete reciprocity in the optical path, and the side mode suppression ratio needs to be increased, while the laser linewidth is relatively wide. This paper proposes a combined filtering structure using a bandpass filter and a cascaded add-drop type fiber ring filter. When realizing bidirectional single longitudinal mode output, the optical path structure is fully reciprocal including polarization state reciprocity, while the side mode suppression ratio is relatively high. The linewidth of the bidirectional laser is around 1.1 kHz, far lower than the previous report of tens of kHz. The fully reciprocal combined filter structure proposed in this paper does not require special devices, and its theoretical system is mature, which is conducive to the subsequent application and improvement of bidirectional single longitudinal mode fiber ring laser.

Muscle system of the penial complex in three species of Hygrophila (Gastropoda: Pulmonata)

The Hygrophila, a group comprising freshwater lung-bearing gastropods, have a complex copulatory apparatus, whose musculature has recently been shown to provide a number of phylogenetically informative characters that appear to concur with the results of molecular phylogenetic analyses. The number of hygrophilan species for which the male copulatory musculature is known, however, is still relatively small. We examined the muscle arrangement in the penial complex (penis and penis sheath) of three species of Hygrophila: Aplexa hypnorum (Linnaeus, 1758) (fam. Physidae), Kolhymorbis bogatovi Zatravkin et Moskvicheva, 1985 (fam. Planorbidae, tribe Segmentinini), and Planorbarius corneus (Linnaeus, 1758) (fam. Planorbidae, tribe Helisomatini) to explore whether the organization of the male copulatory musculature in these species is consistent with the previously proposed phylogenetic hypotheses. In A. hypnorum, the primarily glandular penis sheath has a three-layered musculature with outer and inner circular and intermediate longitudinal layers. The tubular penis also has a three-layered musculature, with the same sequence of muscle fibers as in the penis sheath. In K. bogatovi, the sequence of muscle layers in the penis sheath is essentially the same as in A. hypnorum. Penial musculature is also arranged in three layers, but the intermediate layer consists of small radial, rather than longitudinal fibers and the inner and outer layers are circular. In P. corneus, the boundaries between muscle layers in both penis and penis sheath are somewhat indistinct, but the circular muscles tend to lie close to their outer and inner walls, while the longitudinal fibers are concentrated in the interior. The comparison with other hygrophilan species, in which the copulatory musculature has been previously studied, shows that the male copulatory musculature of K. bogatovi is consistent in arrangement with that of other representatives of Segmentinini and that the phylogenetic lineage leading to P. corneus has probably diverged before the clade Planorbini + Segmentinini. The musculature of the penial complex of A. hypnorum is generally similar to that of another physid, Physella acuta (Draparnaud, 1805), but the penis sheath of P. acuta lacks an outer layer of circular muscle fibers, which may be explained by reduction.

Performance of composite stone beams with prestressed NSM longitudinal CFRP reinforcement subjected to bending

This paper presents an investigation on the performance of stone beams reinforced with prestressed near-surface mounted (NSM) longitudinal carbon fiber reinforced polymer (CFRP) bars subjected to bending. Seven composite stone beams and four bare ones were tested. The test variables included the reinforcement ratio and prestressing level of CFRP bars, and the shear span to depth ratio of the tested beams. Test results showed that, the composite stone beams with either prestressed or non-prestressed reinforcement exhibited a ductile failure with visible deflection and multiple cracks. As the level of prestressing force increased, the cracking load and the shear capacity of composite stone beams increased but the deformation capacity decreased. The increase in reinforcement ratio could suppress the crack propagation and increase the flexural capacity of composite stone beams. As the shear span to depth ratio decreased, the cracking load, the shear capacity, and the peak load corresponding to flexural capacity of composite stone beams increased accordingly. Theoretical models for predicting the cracking and peak moments of composite stone beams were developed based on sectional mechanical analysis, and a good agreement with the experimental results was obtained.

Shear behavior of externally prestressed UHPC beams without stirrups

Shear stirrups in a prestressed ultra-high performance concrete (UHPC) beam might be eliminated due to the high tensile strength of UHPC. This research aims to investigate shear behavior of the externally prestressed UHPC beams without stirrups. Thirteen UHPC beams were tested with the experimental parameters of prestressing level, shear span-to-depth ratio, longitudinal reinforcement ratio, fiber content, and stirrup ratio. The results showed that the beam with the longitudinal reinforcement ratio of 2.0 % under a shear span-to-depth ratio of 2.0 failed in flexure, even though additionally applying a higher prestressing up to 40 % of tensile strength of prestressing tendon. However, the externally prestressed UHPC beams under a shear span-to-depth ratio lower than 2.0 failed in shear. The shear strength of UHPC beam increased with a higher prestressing, lower shear span-to-depth ratio, more longitudinal reinforcements and stirrups, and higher fiber content. French Standard formula and PCI formula for shear design were conservative, irrespective of the existence or absence of stirrups in the prestressed UHPC beam. The calculated results indicated that the externally prestressed UHPC beams met the requirement of shear design codes when no stirrup was employed.

Evaluation of the Shape Memory Effect of Random and Aligned Electrospun Polyurethane Mats with Different Fibers Diameter.

Fibrous shape memory scaffolds composed of thermoplastic polyurethane based on a mixture of polycaprolactone diols were fabricated. The effect of the fiber diameter and arrangement- random (rPU) or aligned (aPU), on crystallinity, mechanical properties, and shape memory was analyzed. The diameters of the fibers were controlled by changing the concentration of polyurethane (PU) solutions in the range of 5% to 16% and fibers alignment by utilization of different collectors. The chemical structure was confirmed by Fourier Transformed Infrared spectroscopy (FTIR), crystallinity was evaluated based on differential scanning calorimetry (DSC,) and mechanical properties were measured by the tensile test. Additionally, shape memory programming was performed using a dynamic mechanical analyzer (DMA), and shape recovery was evaluated in the air and in the water environment. DSC results showed that the electrospinning process did not change the crystallinity or melting temperature of synthesized thermoplastic polyurethanes. The melting temperature of the crystalline switching segments was around 26-27 °C, and the crystalline phase of hard segments was around 130 °C. Shape memory properties were analyzed in the contest of the fiber diameter and alignment of the fibers, while changes in the fibers' diameters from 360 nm to 1760 nm did not result in significant changes in shape recovery coefficient (Rr) especially evaluated in the air. The longitudinal fiber alignment enhanced mechanical and shape recovery to up to 96% for aPU, with the highest fiber diameter when evaluated in water.

Trabeculectomy Augmented with Limited Deep Sclerectomy and Cyclodialysis with Use of Scleral Tissue as a Spacer.

Trabeculectomy remains the most commonly performed surgery for medically uncontrolled glaucoma. Its success in primary open angle glaucoma is approximately 82% in the initial year after surgery and 64% at the end of five years. Lower success rates have been found in secondary glaucomas like neovascular glucoma, uvietic glaucoma, post-traumatic glaucoma, and for repeat surgeries. To illustrate improvement of the efficacy of trabeculectomy, enhancement with cyclodialysis has been introduced. This involves the creation of a cyclodialysis cleft in a controlled manner to allow additional suprachoroidal drainage of the aqueous. Cyclodialysis is the result of the separation of the longitudinal ciliary muscle fibers from the scleral spur, which creates an additional pathway for aqueous humor drainage. However, such a cleft often closes on its own due to associated inflammation caused by the filtration surgery. Deep sclerectomy is a non-penetrating surgery that involves dissection of a scleral patch and excision of a block of scleral tissue, retaining a thin membrane for aqueous drainage. In this study, we introduce a novel surgical technique of combining trabeculectomy with a limited deep sclerectomy and a cyclodialysis in two pseudophakic patients who developed secondary glaucoma after vitreo-retinal surgery with silicone oil insertion. In this technique the excised scleral tissue obtained after deep sclerectomy was utilized as a spacer to maintain the patency of the cyclodialysis cleft.

Experimental study on the flexural behavior of square high-strength concrete-filled steel tube beams with different CFRP wrapping schemes

Recently, carbon fiber reinforced polymer (CFRP) materials have been recommended for strengthening concrete-filled steel tube (CFST) members. In this paper, experimental study is presented to further investigate the flexural behavior of square high-strength concrete-filled steel tube beams with different CFRP wrapping schemes. Results reveal that all of the specimens display the failure of longitudinal fibers at the bottom of the tensile zone when reaching the ultimate state. Meanwhile, the performance of CFRP confined CFST (CFRP-CFST) beams is improved significantly due to the transverse confinement and longitudinal reinforcement of CFRP sheets. For example, the moment capacity of CFST beams of fcu = 62.8 MPa and 128.2 MPa increased by up to 22 % and 34 %, respectively, strengthened with the full scheme. Moreover, for CFST beams of fcu = 128.2 MPa, the half scheme achieved the similar enhancement effect (29 %) in comparison with the full scheme. Based on the experimental results, a simplified approach using the fiber element method is proposed to predict the moment–curvature relationship and ultimate moment capacity of the CFRP-CFST beams. The predictions are validated with the experimental results from this paper and other study. A stepwise analytic approach is developed for designing CFRP-CFST flexural members.

Characterization and Strength Quality of the Oryctolagus cuniculus Leather Compared to Oreochromis niloticus Leather.

This study aimed to compare the resistance of the Oryctolagus cuniculus L. (rabbit) and Oreochromis niloticus L. (Nile tilapia) skins, as well as to observe the design of the flower of these skins and the morphology of the dermis. Tilapia and rabbit skins were placed inside the same equipment (tannery machine) for the chromium salt tanning process. The flower design of the fish leather distinguishes it from the rabbit leather, the latter being constituted by the opening of the hair follicles and pores, while the fish leather is constituted by the presence of protective lamellae and insertion of the scales. The dermis of rabbit skin consists of thick bundles of collagen fibers arranged in all directions, which differs from the morphology observed in the dermis of fish skin. However, in the Nile tilapia skin dermis, overlapping and parallel layers of longitudinal collagen fiber bundles are observed, these layers are interspersed with fiber bundles crossing the sking surface (transversely), tying the fibers together and providing greater strength, which can be proven by the strength test. The fish leathers, despite having less thickness (1.0 mm), demonstrated significantly greater tensile strength (13.52 ± 1.86 N mm−2) and tear strength (53.85 ± 6.66 N mm−2) than rabbit leathers, that is, (8.98 ± 2.67 N mm−2) and (24.25 ± 4.34 N mm−2). However, rabbit leather demonstrated higher elasticity (109.97 ± 13.52%) compared to Nile tilapia leather (78.97 ± 8.40%). It can be concluded that although the rabbit leather is thicker due to the histological architecture of the dermis (thick bundles of collagen fibers arranged in all directions with no pattern of organization of collagen fibers), it shows less resistance than Nile tilapia leather, which demonstrates an organization of overlapping and parallel layers and intercalating collagen fiber bundles transversally to the surface, functioning as tendons for the swimming process. It is recommended to use a piece of fabric (lining) together with the fleshy side of the rabbit leather, to increase resistance when used in clothing and footwear, as these products require greater tensile strength. Thus, it minimizes this restriction for the use of rabbit leather in the aforementioned purposes.

FEM simulation investigation of ultrasonic vibration-assisted grinding of SiCf/SiC composites

In this study, a finite element model (FEM) of a single diamond grinding SiCf/SiC composites was established, and the process of ultrasonic vibration-assisted grinding was simulated and investigated from a microscopic perspective. The damage behavior and removal mechanism of ultrasonic vibration-assisted grinding along across fibers, longitudinal fibers, and transverse fibers were analyzed, respectively. Simulation results show that brittle fracture is the main removal mechanism of the matrix. The damage behavior of fibers mainly includes fiber breakage, fiber fracture, fiber pull-out, and fiber debonding. There are large differences in the removal mechanism of materials ground in different fiber directions. The simulation results provide important guidance for a better understanding of the damage behavior and removal mechanism of ultrasonic vibration-assisted grinding of SiCf/SiC composites.

Steel fiber reinforced RC beams in pure torsion—Load‐bearing behavior and modified space truss model

AbstractInvestigations on steel fiber reinforced concrete (RC) beams in torsion show, that the steel fibers positively influence the torsional load‐bearing behavior. Since a systematic evaluation of the previously known test results and the derivation of a generally valid design model were lacking until recently, current codes such as Model Code 2010 do not contain any design models for the consideration of the steel fiber load‐bearing effect in the torsion design. Due to this, the existing torsion tests on steel fiber RC were summarized in a database. Furthermore, on the basis of the test results and observations, the space truss model developed by Rausch and later refined by Lampert and Thürlimann, among others, was further developed and supplemented by additional longitudinal and transverse steel fiber tension struts. This modified space truss model was validated with the database and shows good to very good predictions to the torsion test data.

Histological and histochemical study of large intestine in Camel (Camelus Dromedarius)

Current study was performed to describe the Histohistological and histochemical structures of the large intestine in Iraqi one humped camel (Camelus Dromedarius). Five healthy male camels Approximately 3 to 4 years old were chosen and their specimens from cecum, colon and rectum. The specimens were directly transferred after the animal’s slaughtering to the histology lab at College of Veterinary Medicine for subsequent histological techniques. Tissue specimensfrom various parts of the large intestine (cecum, colon and rectum) were collected and fixed with 10% neutral buffered formalin then subjected to routine tissue processing. Sections of 6 micrometers thickness were prepared and stained with hematoxylin and eosin (H&E) for general histology and Periodic Acid Schiff combine with Alcian blue (AB–PAS), Masson's trichrome as well as Verhoeff stains for histochemical description. Microscopic findings revealed four tunicae constructing the wall of cecum, colon and rectum mucosa, that were from the inner most mucosa, submucosa, muscularis and the outer most either serosa or adventitia. The tunica mucosa characterized by simple columnar epithelium rested on basement membrane and the presence of muscularis mucosa which separated mucosa from the underneath submucosa. Crypts of Lieberkühn and goblet cells were abundant in the colonic epithelium. The submucosa was made up of irregular connective tissue rich with adipose tissue and was supplied well with many blood vessels. Tunica muscularis in all over the three parts of large intestine was made up of inner circular smooth muscle fibers and outer longitudinal smooth muscle fibers. The tunica serosa, and in parts replaced by adventitia, was made up of loose connective tissues.

Prospects for Developing Low-Cost Optical Fiber Sensors for Liquid-Liquid Interface Detection

This work examines the prospects of a low-cost retroreflection optical sensor system for detection of the interface between two immiscible liquids, for applications in oil separation tanks. The sensor in its simplest configuration comprises a bare fiber optic tip, cleaved at an angle of 90º relative to the longitudinal fiber axis. The device tested experimentally is based on a 2x2 bidirectional coupler, which connects the sensor tip to a laser and two photodetectors, one used to measure the signal and the other as a reference. From experiments conducted in a laboratory wateroil system, the measured retro-reflected signal was very small, and of the same order as the differential signal due to low optical contrast liquids. To overcome this difficulty, the detection system was designed with an amplification stage, followed by filtering of the digitally converted signal. With this strategy, an accuracy of 99.7% was reached. On the light of the performance measured by the bare fiber tip configuration, an analysis on the potential improvement in performance obtained, by applying a thin layer of gold to the tip of the sensor, was made. Simulated results indicated that, for an optimized gold film, 13 nm thick, a 13fold improvement in the sensor detection limit is obtained.

A Study of Diabetic and Non-diabetic Human Cataract Lens by Scanning Electron Microscopy

Published on:August 2022Journal of Young Pharmacists, 2022; 14(3):302-304Original Article | doi:10.5530/jyp.2022.14.59 Authors:Swathy Govindaswamy1,*, Dhivya Sundaram21Department of Pharmacy Practice, KMCH College of Pharmacy, Coimbatore, Tamil Nadu, INDIA.2Department of Biomedical Science, Bharathidasan University, Tiruchirappalli, Tamil Nadu, INDIA. Abstract:Background: This research aimed to ascertain the differences in morphological manifestation in the human diabetic cataractous lens compared to a non-diabetic cataractous lens by Scanning Electron Microscopy (SEM). Materials and Methods: Lens fibers were prefixed in glutaraldehyde and subsequently post-fixed in a Hexamethyldisilazane and examined by SEM. The SEM images gave a comparative morphological impression of the ongoing structural alterations during the degeneration process of human non-diabetic cataracts and diabetic cataract lenses. Results: Diabetic cataractous lens fibers were identified by more chaotic longitudinal fiber splitting, porosity, and granulation of the lens fiber membrane and opening (distortion) of the lens fiber interdigitation system than their non-cataractous diabetic counterparts. Diabetic cataract lenses showed an increased rate of nucleus compaction compared to non-diabetic cataract lenses. Conclusion: The absence of Finger-like and flap projections and the disappearance of the ball and socket system is prominent in diabetic cataract lenses, suggesting the hyperglycaemic effect in the degeneration of lens fibers and further contributes to the early onset of cataracts in diabetes compared to non-diabetic.Keywords: Cataract, Diabetic complications, Morphology, Scanning electron microscopy.

Evaluation of tongue mobility following release operation of ankyloglossia with genioglossus myotomy.

Ankyloglossia is a congenital anomaly characterized by a short lingual frenulum and severe form needs release surgery. Our goal in this study was to confirm the long-term safety and efficacy of Z-plasty with genioglossus myotomy compared with traditional Z-plasty alone and to develop a proper measurement tool to validate the postoperative results of release operations for ankyloglossia. Patients were divided in 2 groups, release with Z-plasty only group (group 1) and Z-plasty combined with genioglossus myotomy group (group 2) In group 2, the release of central longitudinal fiber of genioglossus muscle was added in the conventional Z-plasty operative procedure. To analyze the results of the surgery, we developed an objective assessment tool which is the direct length from the innermost point of the floor of mouth to the tip of the tongue, preoperatively and postoperatively, which is called “functional tongue length.” A total of 101 patients with ankyloglossia ranging in age from 36 months to 8 years underwent release operation. Although there was no significant difference in terms of postoperative measurements between groups in Kotlow class II, group 2 patients in Class III and IV showed greater postoperative functional tongue length. Also, there was no significant complication requiring secondary surgery. Our study demonstrated that adding genioglossus myotomy to a simple Z-plasty is a safe and effective method for improving the tongue mobility required to make lingual sounds, especially in moderate to severe form of ankyloglossia, along with suggestion of a new measurement tool, which can objectively assess tongue mobility with possibility for universal utilization in ankyloglossia release operation.

Flexural Strengthening of Prestressed Girders with Partially Damaged Strands Using Enhancement of Carbon Fiber Laminates by End Sheet Anchorages

This paper examines the impact of flexural strengthening on the percentage of damaged strands in internally unbonded tendons in partially prestressed concrete beams (0, 14.28%, and 28.57%) and the recovering conditions using CFRP composite longitudinal laminates at the soffit, and end anchorage U-wrap sheets to restore the original flexural capacity and mitigate the delamination of the soffit of longitudinal Carbon Fiber Reinforced Polymer (CFRP) laminates. The composition of the laminates and anchors affected the stress of the CFRP, the failure mode, and thus the behavior of the beam. The experimental results revealed that the usage of CFRP laminates has a considerable impact on strand strain, particularly when anchors are employed. The EB-CFRP laminates increased the flexural capacity by approximately 13%, which corresponds to strand damage of 14.28%, while flexural capacity increased by 9.3%, strand damage increased by 28.57% for members strengthened with laminates only, and around 21.58% and 16.85% for members reinforced with laminates and end anchorings. Quasi-experimental equations have been proposed to estimate the actual stress of untethered tendons considering the effect of CFRP laminates and final fixation winding.

Observation of the interaction between transverse cracking and fibre breaks in non-crimp fabric composites subjected to cyclic bending fatigue damage mechanism

This work presents observations of fatigue damage in a quasi-unidirectional polymer reinforced composite made from basalt fibre non-crimp fabric and epoxy. Through observations over large areas, the study provides quantitative observations of the damage caused by the cyclic bending loads, with focus on the damage in the tension-tension loaded region of the specimens. The observations reveals that the fatigue damage mechanism that governs the stiffness degradation of the composite occurs only in regions subjected to tensile stresses. Damage incurred from tensile loads are governed by local interactions between transverse and longitudinal fibre bundles. It is determined that cracks in transverse bundles interact with longitudinal bundles to cause breakage of fibres. These fibre breaks are found to be the main driver for stiffness degradation of the material. Similar accounts exists in the literature based on qualitative observations. The current study provides evidence, in the form of quantifiable observations, to further strengthen the argument for considering the damage mechanism as the main cause of stiffness degradation in quasi-unidirectional non-crimp fabric composites.

Numerical verification for concrete beams reinforced with CFRP subjected to pure torsion

Torsional behavior of concrete beams reinforced with longitudinal Fiber reinforced polymers (FRP) bars and FRP transverse stirrups has not been well-defined in various international codes and design guidelines as evidenced from the discrepancies in design equations. Such discrepancies are due to the complex behavior of beams subjected to torsional stresses and the limited research available in the literature; especially for FRP reinforced beams. A non-linear finite element (FE) analysis is conducted using ATENA software to generate a numerical model to predict and verify the failure loads and strains of beams of a compiled database from literature. This paper presents a comparison between the results of the experimental data and analytical models in order to verify the efficiency of the proposed numerical model for predicting failure load/strains in longitudinal FRP bars, FRP stirrups, and rotation angle of the tested beams. The comparison showed good agreement between experimental and analytical models in ultimate torque with difference of 6.5 % and the model is used in a parametric study to investigate the effect of concrete compressive strength, longitudinal reinforcement ratio, and beam depth under pure torsion in addition to the effect of concrete contribution to the torsional resistance. The numerically computed cracking and ultimate torques are compared with results from theory of elasticity, skew-bending theory and code equations such as: ACI-318 and CSA-S806-12. Based on this study, CSA-S806 gives acceptable prediction of ultimate torque, while ACI code is found to be more conservative. The increase of concrete compressive strength can enhance the cracking and ultimate torque. The increase of longitudinal reinforcement ratio has an insignificant effect on ultimate torque but increases the twist capacity of Reinforced concrete (RC) beams. The increase of longitudinal reinforcement can improve also the twist ductility.

Flexible Mechanoluminescent SrAl2O4:Eu Film with Tracking Performance of CFRP Fracture Phenomena.

Non-destructive testing of carbon-fiber-reinforced plastic (CFRP) laminates with bidirectional fiber bundles (twill-weave) using a mechanoluminescence (ML) technique was proposed. The dynamic strain distributions and fracture phenomena of the CFRP laminates in the tensile testing were evaluated by the fabricated ML sensor consisting of SrAl2O4:Eu (SAOE) powder and epoxy resin. The ML images for the ML sensor attached to the CFRP laminates with bidirectional fiber bundles gave a net-like ML intensity distribution similar to the original twill weave pattern. Specifically, it was found that the ML intensity on the longitudinal fiber bundle, which is the same as the tensile direction, is higher than that on the transverse fiber bundle. This indicates that the ML sensor can visualize the load share between fiber bundles in different directions of the CFRP laminate with high spatial resolution. Meanwhile, the ML sensor could also visualize the ultrafast discontinuous fracture process of the CFRP laminates and its stress distribution. The amount of SAOE powder in the ML sensor affects the tracking performance of the crack propagation. A higher SAOE amount leads to a fracture of the ML sensor itself, and a lower SAOE amount leads to poor ML characteristics.

Identifying locations susceptible to micro-anatomical reentry using a spatial network representation of atrial fibre maps.

Micro-anatomical reentry has been identified as a potential driver of atrial fibrillation (AF). In this paper, we introduce a novel computational method which aims to identify which atrial regions are most susceptible to micro-reentry. The approach, which considers the structural basis for micro-reentry only, is based on the premise that the accumulation of electrically insulating interstitial fibrosis can be modelled by simulating percolation-like phenomena on spatial networks. Our results suggest that at high coupling, where micro-reentry is rare, the micro-reentrant substrate is highly clustered in areas where the atrial walls are thin and have convex wall morphology, likely facilitating localised treatment via ablation. However, as transverse connections between fibres are removed, mimicking the accumulation of interstitial fibrosis, the substrate becomes less spatially clustered, and the bias to forming in thin, convex regions of the atria is reduced, possibly restricting the efficacy of localised ablation. Comparing our algorithm on image-based models with and without atrial fibre structure, we find that strong longitudinal fibre coupling can suppress the micro-reentrant substrate, whereas regions with disordered fibre orientations have an enhanced risk of micro-reentry. With further development, these methods may be useful for modelling the temporal development of the fibrotic substrate on an individualised basis.

Superior Longitudinal Fasciculus: A Review of the Anatomical Descriptions With Functional Correlates.

The superior longitudinal fasciculus (SLF) is part of the longitudinal association fiber system, which lays connections between the frontal lobe and other areas of the ipsilateral hemisphere. As a dominant association fiber bundle, it should correspond to a well-defined structure with a clear anatomical definition. However, this is not the case, and a lot of confusion and overlap surrounds this entity. In this review/opinion study, we survey relevant current literature on the topic and try to clarify the definition of SLF in each hemisphere. After a comparison of postmortem dissections and data obtained from diffusion MRI studies, we discuss the specifics of this bundle regarding its anatomical landmarks, differences in lateralization, as well as individual variability. We also discuss the confusion regarding the arcuate fasciculus in relation to the SLF. Finally, we recommend a nomenclature based on the findings exposed in this review and finalize with a discussion on relevant functional correlates of the structure.