Adjacent Laminae Research Articles

Retinal Input Is Required for the Maintenance of Neuronal Laminae in the Ventrolateral Geniculate Nucleus.

Retinal ganglion cell (RGC) axons provide direct input into several brain regions, including the dorsal lateral geniculate nucleus (dLGN), which is important for image-forming vision, and the ventrolateral geniculate nucleus (vLGN), which is associated with nonimage-forming vision. Through both activity- and morphogen-dependent mechanisms, retinal inputs play important roles in the development of dLGN, including the refinement of retinal projections, morphological development of thalamocortical relay cells (TRCs), timing of corticogeniculate innervation, and recruitment and distribution of inhibitory interneurons. In contrast, little is known about the role of retinal inputs in the development of vLGN. Grossly, vLGN is divided into two domains, the retinorecipient external vLGN (vLGNe) and nonretinorecipient internal vLGN (vLGNi). Studies previously found that vLGNe consists of transcriptionally distinct GABAergic subtypes distributed into at least four adjacent laminae. At present, it remains unclear whether retinal inputs influence the development of these cell-type-specific neuronal laminae in vLGNe. Here, we elucidated the developmental timeline for these laminae in the mouse vLGNe, and results indicate that these laminae are specified at or before birth. We observed that mutant mice without retinal inputs have a normal laminar distribution of GABAergic cells at birth; however, after the first week of postnatal development, these mutants exhibited a dramatic disruption in the laminar organization of inhibitory neurons and clear boundaries between vLGNe and vLGNi. Overall, our results show that while the formation of cell-type-specific layers in mouse vLGNe does not depend on RGC inputs, retinal signals are critical for their maintenance.

Failures of laminates under nonpenetrative impacts

Various failures of laminates under low-velocity impacts without penetration are simulated systematically with a limited number of inputs, all measurable following existing standards without any data calibration. No iteration is required to determine any of the failures investigated in this work. Any two adjacent lamina (primary) layers are inserted with a matrix (secondary) layer, whose stresses are modified through two modification coefficients (MCs). The MCs are determined through peak loads of double cantilever beam and end-notched flexure tests on unidirectional laminates, and their weak sensitivity to sample dimensions is shown. Delamination is reproduced by deleting failed secondary-layer elements. The homogenized stresses of fiber and matrix obtained by Bridging Model are converted into true values through the author’s true stress theory to estimate constituent-induced intralaminar failures, such as fiber breakage, matrix crack and interface debonding, against the monolithic fiber or matrix strengths measured independently. Primary- layer elements attaining a fatal failure (fiber breakage or matrix crack accompanied with a critical strain condition) are deleted before an impact termination corresponding to separation of the impactor from target. The predicted delamination areas and impact force, displacement and energy histories for the laminates of three lamination angles under different impact energies agree well with our measured counterparts, validating the efficiency of the simulation.

Modelling of Mode I delamination using a stress intensity factor enhanced cohesive zone model

Cohesive zone modelling is a common approach to capture delamination in composite laminate structures. Recent experimental advancements now enable the direct measurement of Mode I traction-separation responses (TSRs) from a single specimen using the composite rigid double cantilever beam (cRDCB), overcoming a major obstacle in using cohesive zone modelling to model delamination. However, TSRs measured experimentally with the cRDCB specimen capture damage response as well as the stiffness contribution of the adjacent laminae, which can introduce significant artificial compliance into numerical models when modelling delamination separately from intralaminar behaviour. A two-stage analysis procedure utilizing a crack tip compensation function is presented to enhance the TSRs measured with the cRDCB specimen to accurately model Mode I delamination. The analysis procedure is demonstrated to improve the accuracy of delamination prediction within the statistical variation of published experimental data. Furthermore, the transferability of TSRs measured with cRDCB specimens is explored using available experimental DCB data. It is shown that the onset of damage and early damage behaviours measured with the cRDCB specimen appear to be transferable between geometries, whilst large-scale damage mechanics remain geometry dependent.

Diagenetic alterations induced by lamina-scale mass transfer and the impacts on shale oil reservoir formation in carbonate-rich shale of the Permian Lucaogou Formation, Jimusar Sag

Diagenesis plays a crucial role in shale oil reservoir formation. However, complex organic-inorganic interactions result in pore system formation and heterogeneity changes at the centimeter, or even micrometer scale, which controls the evolution of shale oil reservoirs. In this paper, an integrated approach including core observation, thin section observation, cathodoluminescence thin section observation, scanning electron microscope, μ-XRF analysis, electron microprobe analysis, AMICS analysis, LA-ICP-MS analysis, and isotope analysis was used to clarify the laminae combination carbonate-rich shale, diagenetic alterations in different types of shale laminae and the controls on shale oil reservoir formation. According to the lamina combination, the carbonate-rich shale in the Permian Lucaogou Formation can be divided into three types. They are shale consists of dolomitic lamina and terrigenous felsic lamina (Type A shale), shale consists of calcite-rich tufaceous lamina and terrigenous felsic lamina (Type B shale) and shale consists of calcareous lamina and tufaceous lamina (Type C shale). Dolomite cementation is the major diagenesis in terrigenous felsic lamina of Type A shale. The dolomite can be identified as the early stage forming from recrystallization of micrite dolomite, and the late stage precipitate from adjacent dolomitic lamina. In the terrigenous felsic lamina of Type B shale, however, the calcite cementation is the dominated diagenesis, which was sourced from adjacent calcite-rich tufaceous lamina. Also, some feldspar dissolutions occurred in terrigenous felsic lamina during organic matter evolution. For the Type C shale, the main diagenetic alteration is micrite calcite recrystallization in calcareous lamina. The dissolution and precipitation of carbonate minerals between different laminae of carbonate-rich shale reveal that the organic matter evolution significantly influence the diagenetic alterations of inorganic minerals. Particularly, the diagenetic mass transfer and redistribution at the micro-scale in a relatively diagenetic system were confirmed by organic-inorganic interactions in laminated shale. In this process, dissolution pores and recrystallization pores have provided considerable reservoir pores for shale oil.

B- and T-cell lymphocytes and other immune cell infiltration in the duodenal and rectal mucosa of severe asthmatic horses.

The objectives of this study were to quantify lymphocytes and eosinophils in the mucosa of the duodenum and rectum in asthmatic horses. 8 healthy and 10 asthmatic horses. Asthmatic horses were evaluated in a symptomatic (after 6 weeks of exposure to moldy hay) and asymptomatic status (3 and 7 months after being fed alfalfa pellets [n = 4] or treated with inhaled fluticasone [6]). Duodenal and rectal biopsies were endoscopically (n = 4 to 6) taken in each horse. Eosinophils were counted on slides stained with hematoxylin, eosin, phloxine, and saffron, and immunohistochemistry was used to evaluate T and B lymphocytes using CD3 and CD20, respectively. The duodenal and rectal epithelium of asthmatic and control horses contained exclusively T lymphocytes (CD3). Symptomatic asthmatic horses, compared to controls, had a significantly higher number of T lymphocytes (CD3) in the duodenal epithelium (P = .016) and the adjacent lamina propria of the villi (P = .04). Compared to symptomatic asthmatic horses, the fluticasone-treated group had significantly fewer T lymphocytes in the total lamina propria of the rectal mucosa (P < .01). Taken together, these results suggest that asthmatic horses have greater infiltration of T lymphocytes in the duodenal and rectal mucosa, indicating a certain degree of inflammation, which could be due to a systemic inflammatory effect and/or a local effect of ingested hay allergens in asthmatic horses. Systemic markers of inflammation have not been investigated to better qualify if the infiltration noted is due to a local and/or systemic effect.

Load-Bearing Shifts in Laminar and Ligament Morphology: Comparing Spinal Canal Dimensions Using Supine versus Upright Lumbar MRI in Adults without Back Pain.

Purpose The effects of weight bearing on lumbar spinal canal dimensions are not well reported the low back pain (LBP) literature. Since axial loading induces changes in anatomical configuration of the lumbar spine, supine spine imaging may not uncover dimensional changes associated with physiological weight bearing that could be demonstrated in imaging in the upright position. Methods This study compared anteroposterior spinal canal dimensions measured at the level of the intervertebral discs in the supine and upright lumbar spine magnetic resonance images in adults without a history or current back pain. Additionally, interlaminar distances were measured between the centers of adjacent laminae involving a spinal segment. These parameters were utilized to ascertain the deformation incurred at the ligamentum flavum due to load bearing. Results Within and between-sessions t -tests, factorial and repeated-measures analysis of variance showed significant alterations in canal dimensions at certain levels, secondary to the upright positioning of the spine. Measurement reliability assessed between sessions and scanning positions using intraclass correlation coefficients demonstrated strong agreement. Conclusion Imaging studies involving physiological weight bearing may be useful to understand the potential etiological effects of such changes in mechanical LBP.

Piezo1 involves in intracellular osteogenic transformation signal to promote the ossification of ligamentum flavum

Ectopic osteogenesis refers to the occurrence of osteoblasts in soft tissues other than bone tissue and the formation of bone tissue. The ligamentum flavum is an essential connecting structure between adjacent vertebral lamina, which participates in the formation of the vertebral canal's posterior wall and maintains the vertebral body's stability. Ossification of the ligamentum flavum (OLF) is one of the manifestations of systemic ossification of the spinal ligaments and one of the degenerative diseases related to the spine. However, there is a lack of research on the expression and biological function of Piezo1 in ligamentum flavum. Whether Piezo1 participates in the development of OLF is still unclear. The FX-5000C cell or tissue pressure culture and real-time observation and analysis system was applied to stretch ligamentum flavum cells to detect the expression of mechanical stress channel and osteogenic markers after the effect of different stretching durations. The results showed elevated expression of mechanical stress channel Piezo1 and osteogenic markers with the effect of tensile time duration. In conclusion, Piezo1 involves in intracellular osteogenic transformation signal to promote the ossification of ligamentum flavum. An approved explanatory model and further research will be required in the future.

Prospective Study of Posterior Cervical Foraminotomy for Cervical Radiculopathy in Absenceof Myelopathy

Objective: To determine clinical and patient satisfaction outcomes after posterior cervical foraminotomy (PCF), for the patients suffering from cervical monoradiculopathy, in the absence of myelopathy. To assess the efficacy of PCF. Methods: This was a prospective and multicentric study including patients of cervical monoradiculopathy, who underwent PCF surgery in the “department of orthopedics,” between October 2020 and November 2022. The hospital records, images, operation notes, and follow-up records were reviewed and analyzed. Thirty patients of cervical monoradiculopathy were investigated. All the patients who have satisfying inclusion criteria in the study period from October 2020 to November 2022 were included in the study. Patients of any age group and both the sexes and who were operated for PCF were considered. Those patients were then meticulously subjected to thorough inspection, with the help of hospital records, images, and operation notes and interviews. All the details of the patients were obtained based on previous hospital records and interactions with them and through neck disability index (NDI) score. Discussion: Decompression of the nerve root can be done by either anterior or posterior approach. Anterior approach carries risk of damaging oesophagus, trachea, carotid sheath and recurrent laryngeal nerve posterior approach includes foraminotomy in form of drilling some part of facet joint and adjacent lamina, disc can also be removed in selected cases this approach do not carry much risk. Many comparative studies shows equal beneficial outcome of pcf (posterior cervical foraminotomy)as compared to acdf (anterior cervical disectomy with fusion). Results: When we analyzed the NDI scores at different intervals there has been a positive trend showing the improvement in overall well being of an individual patient and this has resulted in major porting of the patients that has been taken as a sample has returned to there normal day to day living which they used to have earlier, before suffering from cervical radiculopathy. Conclusion: The final conclusion that can be drawn after analyzing the NDI score at different interval of time i-e before surgery, immediately and after surgery, 6 weeks post surgery, 3 months post surgery and 6 months post surgey is that patients have shown successive improvements with every follow up done.

Weibull reliability plots to study the strain rate effect on interfacial strengths of carbon fiber reinforced epoxy composites

AbstractTwo‐parameter Weibull reliability plots are utilized to determine the effects of strain rate on the interfacial strengths of unidirectional carbon fiber reinforced epoxy (CFRE) composites. Laminate specimens with two different fiber orientations are tested to failure under flexural loading. Type 1 laminates with fibers running parallel to specimen length (fiber orientation of 0° with respect to specimen span length) enable measuring inter‐laminar shear strength (ILSS) of the interface (between adjacent lamina) with locus of failure along beam mid ply. Seventy‐two type 1 laminates are tested at five levels of flexural strain rates: 1.89 * 10−5 to 9.37 * 10−2 s−1. Type 2 laminates with fibers running perpendicular to specimen length (fiber orientation of 90° with respect to specimen span length) enable measuring intra‐laminar (matrix/fiber) peel strength (ILPS) for tensile (mode I) strength of the matrix/fiber interface with locus of failure at beam bottom ply. Thirty‐six type 2 laminates are tested at three levels of flexural strain rates: 2.09 * 10−5 to 3.49 * 10−3 s−1. For each level of strain rate, Weibull plots are constructed. Stress values at failure probability (Pf) of 63.1% are assigned as strength values. The results show a slight decrease of the Weibull modulus, m, with increasing strain rates. The modulus decreases from 12.37 to 10.49 and from 11.11 to 9.68, for laminates type 1 and 2, respectively. For laminates type 1, ILSS increases with increasing strain rates rising 16.1% over the range of the tested strain rates. For laminates type 2, ILPS increases with increasing strain rates rising 38.1% over the range.

Effects of types and content of clay minerals on reservoir effectiveness for lacustrine organic matter rich shale

As a promising supplement of China’s petroleum production, the lacustrine shale, compared with the marine shale, is characterized by higher clay mineral content, which has significant impacts on the hydrocarbon reservoir quality. Controlled by the paleo-lacustrine background and thermal maturity, the clay mineral contents vary tremendously in different shale systems. This study targets on three shale series formed in different basin types, namely the Lucaogou Formation shale (Junggar Basin), the Chang 7 Member shale (Ordos Basin), and the Qingshankou Formation shale (Songliao Basin), where the Junggar Basin was a saline lacustrine basin and the latter two were freshwater-brackish lacustrine basins. We find that the composition and content of clay minerals are considerably varied among the three shales that the clay mineral content of the Lucaogou formation shale is smaller than that of the Chang 7 Member and Qingshankou Formation, and the content of illite in the Chang 7 shale is lower than that in the Qingshankou shale. The occurrence of clay minerals has crucial effects on pore structures, that is the pore-filling clays has indiscernible contribution to the storage space, like in the Lucaogou shale, but those developing along the shale laminae can improve the storage capacities to form inter-granular pores and micro-fractures such as in Chang 7 Member and Qingshankou Formation. The development of clay mineral-related pores and fractures is controlled by thermal maturity (Ro) and affected by the content of terrigenous minerals. This pore structure alteration derived by the clay mineral occurrence types further affects the hydrocarbon contents. In the Lucaogou shale, the oil content is inversely proportional to clay mineral contents, while in Qingshankou Formation, the oil content is even higher than that of the adjacent felsic silt laminae due to the favorable development of micro-fractures and inter-granular pores in clay mineral laminae. The high clay mineral content in lacustrine shales in China make it necessary to investigate the clay mineral evolution to evaluate the hydrocarbon generation potential, pore structures, hydrocarbon contents, and hydrocarbon accumulation mechanisms in shale systems.

Origin and significance of authigenic quartz and albite in lacustrine calcareous fine-grained sedimentary rocks

Generally, researchers believe that authigenic quartz precipitates in acidic medium and authigenic albite precipitates in alkaline medium. However, the lacustrine carbonate-rich fine-grained sedimentary rocks in the upper fourth sub-member and the lower third sub-member (Es4s–Es3x) of the Shahejie Formation in the Jiyang Depression were observed and it was found that authigenic microcrystalline quartz and albite generally develop together. Moreover, authigenic quartz and albite also develop with microcrystalline Fe-rich dolomite and calcite in clay laminae, while in carbonate laminae, they primarily develop with recrystallized calcite. In this study, thin-section, cathodoluminescence, field-emission scanning electron microscopy (FESEM), laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and inclusion analyses were conducted to study authigenic minerals. The results show that authigenic quartz and albite are characterized by rich Ge in mudstone, and the material components mainly originate from the transformation of clay minerals and the dissolution of terrigenous feldspar debris. In limestone, they are characterized by poor Ge, and the material components primarily originate from the transformation of clay minerals. The paragrowth and intergrowth of authigenic quartz and albite primarily depend on the degree of supersaturation of the corresponding ion concentration under high temperature, high or ultrahigh pressure. During the early diagenetic stage, authigenic quartz and albite initially formed in a weakly alkaline environment; however, on entering the middle diagenetic period, authigenic quartz, albite, and sparry calcite formed in a weakly acidic environment, and the formation rate reached its peak. Our results elucidate the migration direction and enrichment law of shale oil in calcareous fine-grained sedimentary rocks through the genetic mechanism of authigenic quartzs and albites. Shale oil is generated from organic matter in the clay lamina, following which it migrates, accumulates, and preserves to the adjacent sparry calcite lamina under the joint driving effect of organic matter hydrocarbon generation overpressure and clay mineral dehydration overpressure.

Single Cell RNA Sequencing Reveals Deep Homology of Dental Cell Types Across Vertebrates

Like most mammals, humans replace their teeth once throughout their lives and have limited regenerative capabilities. In contrast, mice continually renew tissues lost due to gnawing through a well characterized population of stem cells on the labial surface of the incisor. Most non-mammalian vertebrates replace teeth throughout life; the cellular and molecular mechanisms of successional tooth replacement are largely unknown. Here we use single nuclei RNA sequencing (snRNA-seq) of replacement teeth and adjacent oral lamina in Lake Malawi cichlids, species with lifelong whole–tooth replacement, to make two main discoveries. First, despite hundreds of millions of years of evolution, we demonstrate conservation of cell type gene expression across vertebrate teeth (fish, mouse, human). Second, we used an approach that combines marker gene expression and developmental potential of dental cells to uncover the transcriptional signature of stem-like cells in regenerating teeth. Our work underscores the importance of a comparative framework in the study of vertebrate oral and regenerative biology.

Prediction of laminate delamination from strength failure of interlaminar matrix-layer

Prediction of laminate delamination can be achieved by assessing strength failure of an interlaminar matrix-layer inserted in between the laminae, but the thus obtained matrix-layer stresses are generally out of expectation. In this paper, two MCs (modification coefficients) determined from the loads for measuring Modes I and II interlaminar fracture toughnesses are utilized to refresh the normal and shear stresses of matrix-layer, so that the matrix-layer would fail before a laminate failure. This method proves appropriate to simulate delamination induced by different loads. Once the modified stresses of a matrix-layer element fulfill a strength failure condition, it is deleted and the two adjacent lamina elements are delaminated from each other. The delamination behavior and its influence on the ultimate load sustainability of the laminate are investigated. Good correlation between predicted and measured results under different loading modes confirms the efficiency of this work.

Deformation and failure of a novel fiber-metal hybrid lamina composite under quasi-static and impact loading

A novel composite comprising two laminae, each integrating fiber and metal within a single layer, is established, with the objective of addressing the common problem of structural degradation via debonding between composite and metals in conventional Fiber-Metal Laminates (FMLs). Each lamina consists of an aluminium sheet with rectangular perforations punched out in a grid-like pattern; basalt roving is then “woven” into the sheet by running parallel strips of roving in one direction through the perforations, alternating above and below of metal segments. This results in interlocking of the roving and metal constituents, and the lamina can be considered an assembly of many small metal-composite interface (MCI) units, where the roving and metal are in mutual contact. Two such laminae are stacked together, and epoxy is infused into them to create a bi-layer composite. Specimens are then subjected to quasi-static and projectile impact tests, to examine the deformation and failure induced. Examination of post-test samples show failure and debonding within only a limited number of MCI units in a lamina, because of the intimate integration and interlocking between the fiber and metal components. Moreover, no debonding between the two adjacent laminae is observed. This indicates that the novel architecture of the composite, endows it with excellent resistance against crack propagation, not only within MCI units, but also within the basalt-reinforced epoxy component. It is envisaged that with appropriate optimization, the mechanical properties of these new fiber-metal composites can be further enhanced and implemented in applications where conventional FMLs encounter limitations.

Lead Migration in Neuromodulation

We describe a simple technique of securing surgically implanted leads for spinal cord (SCS), dorsal root ganglion (DRG) and occipital nerve stimulation (ONS), for both primary surgical implantation and correcting lead migration. This technique could also be adapted for securing percutaneously implanted leads. Thirty-nine patients underwent neurosurgical implantation of SCS, DRG, and ONS devices utilizing titanium mini-plates to obtain secure anchorage of leads to adjacent laminae close to their exit point from the epidural space, thereby minimizing the risk of further lead migration or electrode displacement. There were no cases of primary or recurrent lead migration in any patient undergoing lead placement using mini-plate anchorage. The technique appears to offer a reliable means of preventing post-operative lead migration in a variety of spinal and extra-cranial neuromodulation implants.

Finite element modeling ofCFRPcomposite tubes under low velocity axial impact

AbstractThe dynamic axial crushing response of circular tubes made of unidirectional carbon fiber‐epoxy composite was investigated numerically applying a new approach to the modeling of the delamination process. In the proposed approach, delamination (interface damage) was modeled by inserting isotropic resin plies capable of damage. They are tied to the adjacent laminae and replace the commonly used surface‐based cohesive model. Two multi‐layer models of laminated tubes having cross‐ply and angle‐ply stacking sequences were simulated using stacked conventional shell elements layers to capture the crushing response and intralaminar and interlayer damage of laminated tubes. The progressive failure analysis in Abaqus/Explicit was utilized to model the successive damage of both the interface and laminae. Both the intralaminar layers and isotropic resin layers were modeled by the conventional reduced integration shell element (S4R). The suggested modeling technique offers some advantages compared to the main‐stream interface modeling of the axial impact of laminated tubes. The computational cost is reduced and yet accurate predictions are obtained. The FE models based on the proposed delamination approach were validated by experimental test results obtained by the authors for cross‐ply and angle‐ply tubes subjected to a low‐velocity impact.

The influence of fibre orientation and of the adjacent layers on the delamination of laminated composites

The paper presents a comparative analysis between different configurations of composite laminates with respect to the delamination onset and growth. The results are presented in terms of the total displacement jumps at the crack tip for an initial imposed displacement up to the final delamination. Therefore, the influence of fibre orientation and the suitable selection of the configuration of the composite laminates are discussed. Moreover, the effect of the adjacent layers on the interlaminar damage of composite laminates is analysed. In this context, a significant number of numerical models have been carried out for two different configurations of multi-layered composites, namely [05/+θ/+θ/05] and [05/+θ/-θ/05]. The influence of the orientation of the adjacent layers is investigated, as well as the sign of the fibre orientation angles. The analysed composite laminates are subjected to tensile opening fracture mode, considering a pre-existing initial crack located at the interface between the layers from the middle plane. The variation of the mode I opening displacement with respect to the fibre orientation angle of the adjacent layers is graphically illustrated. The obtained results show similarities in the variation of Poisson’s ratio with respect to the fibre orientation. Therefore, the mismatch of the Poisson’s ratio of the adjacent laminas may involve significant interlaminar stresses which can lead to a delamination failure or an opening fracture mode.

Prediction of laminate delamination with no iteration

To simulate laminate delamination using least input parameters and with no iteration is still a challenge. As the laminate is essentially bonded from individual laminae by the matrix, there exists a matrix-layer between two adjacent lamina ones, and a delamination of them must be resulted from a matrix-layer failure. However, a three-dimensional finite element analysis indicates that the stresses of the matrix layer are generally so small that it cannot fail before one of the adjacent laminae assumes a failure. This contradiction suggests that there must be something missing from the elemental stresses of the matrix-layer near the delamination front. We introduce a modifying coefficient (MC) to the matrix-layer stresses, and the modified stresses are checked with a strength-failure criterion. Once a tensile or shear failure is attained, delamination occurs to the adjacent laminae. At any load step, either the layers of an element are completely bonded together or completely separated from each other. No iteration is necessary to identify a delamination in the element. Only an additional critical energy release rate from a DCB test is required. Reasonable correlation between predicted delamination propagations and free-edge delamination initiations and measured counterparts of a number of laminates confirm the efficiency of this work.

Development of the Vestibular Lamina in Human Embryos: Morphogenesis and Vestibule Formation.

The vestibular lamina (VL) is a transient developmental structure that forms the lip furrow, creating a gap between the lips/cheeks and teeth (oral vestibule). Surprisingly, little is known about the development of the VL and its relationship to the adjacent dental lamina (DL), which forms the teeth. In some congenital disorders, such as Ellis-van Creveld (EVC) syndrome, development of the VL is disrupted and multiple supernumerary frenula form, physically linking the lips and teeth. Here, we assess the normal development of the VL in human embryos from 6.5 (CS19) to 13 weeks of development, showing the close relationship between the VL and DL, from initiation to differentiation. In the anterior lower region, the two structures arise from the same epithelial thickening. The VL then undergoes complex morphogenetic changes during development, forming a branched structure that separates to create the vestibule. Changing expression of keratins highlight the differentiation patterns in the VL, with fissure formation linked to the onset of filaggrin. Apoptosis is involved in removal of the central portion of the VL to create a broad furrow between the future cheek and gum. This research forms an essential base to further explore developmental defects in this part of the oral cavity.

The Role of TREK-1 and AQP5 in Gonadocorticoid-Related Voice Disorders

TWIK-related potassium channel-1 (TREK-1) and Aquaporin 5 (AQP5) are involved in epithelial integrity and fluid transport, respectively. In this study, we aimed to compare physiological and gestational patterns of TREK-1 and AQP5 location and expression in rat larynx. Our secondary objective was to reveal the effect of estradiol (E2) and progesterone (PG) on these two biomolecules. This study was conducted on 20 Wister albino female rats which were assigned as control (group A) and pregnant group (group B). The rats were sacrificed at 20th day of pregnancy. Blood was obtained directly from the ventricle for detection of serum E2 and PG levels. Larynx was resected for immunohistochemical analyses and real-time polymerase chain reaction testing for detection of TREK-1 and AQP5 staining and expression, respectively. Relative TREK-1 (P=0.035) and AQP5 (P=0.019) expression was found to be significantly high in group B when compared with group A. We found positive correlation between serum E2 levels and both biomolecules (TREK-1; P=0.018, AQP5; P=0.016). We also found positive correlation between serum PG levels and both biomolecules (TREK-1; P=0.001, AQP5; P=0.019). TREK-1 immunostaining was found to be higher in surface epithelium and lamina propria of vocal cord mucosa. AQP5 was particularly found to be located in basement membrane and adjacent superficial lamina propria. We revealed the physiological and gestational pattern of laryngeal TREK-1 and AQP5 expression for the first time. Gestational expression of both TREK-1 and AQP5 was found to be increased. Stimulatory effect of E2 and PG on laryngeal TREK-1 and AQP5 expression was also revealed. We revealed upregulatory effect of E2 and PG on laryngeal TREK-1 and AQP5 expression. Based on this finding, it can be suggested that TREK-1 and AQP5 play role in biomolecular processes leading gonadocorticoid-related voice changes.