Labyrinth Structure Research Articles

SCAP knockout in SM22α-Cre mice induces defective angiogenesis in the placental labyrinth

The placental labyrinth is important for the exchange of nutrients and gases between the mother and the embryo in mice. This interface contains cells of both trophoblast and allantoic mesodermal origin that together produce maternal blood sinuses and placental blood vessels. However, the molecular mechanisms that take place during process of placental labyrinth development, especially concerning fetal capillaries, are not well understood. SREBP cleavage-activating protein (SCAP), a membrane protein, is required for the synthesis of fatty acids and cholesterol. Recently, when we crossed the offspring of the cross between smooth muscle 22 alpha (SM22α)- Cre recombinase (Cre) mice and SCAPloxp/loxp mice to research the function of SCAP in vascular smooth muscle cells (VSMCs) during certain pathological processes, we found that there were no resultant SM22α-Cre-specific SCAP knockout (KO) pups (SM22α-Cre+SCAPflox/flox; hereafter referred to as SCAP KO). Through anatomic studies of these embryos and placentas, we found that SCAP KO resulted in defective placental vessels and abnormal fetal morphology. Further immunohistochemical and immunocytochemical analyses suggested that SCAP is knocked out in the pericytes of the placental labyrinth. Compared to wildtype mice, SCAP KO placentas had abnormal vasculature in the labyrinth and lower levels of angiogenesis. By using RNA-seq and western blotting, we found that the expression of some genes and proteins in SCAP KO placentas was changed, including those related to pericyte/endothelial interactions genes and angiogenesis. Our results suggest that the proper organizational structure of the placental labyrinth depends on SCAP expression in pericytes.

Internal structures and elastic properties of concentrated magnetorheological fluids

Aggregation of non-Brownian magnetizable particles and elastic properties of a magnetorheological suspension placed in an external magnetic field are studied by using computer simulations. The results demonstrate branched labyrinth structures as well as nonmonotonic dependence of the shear stress vs. macroscopic shear deformation with a maximum at a certain deformation.

“Labyrinthine structure” anticorrosive water-based composite coatings

A new environmentally friendly modified graphene oxide/waterborne epoxy composite coating (W-EMGO) is reported. The composite coating, developed by introducing graphene oxide modified with [3-(2-aminoethyl) aminopropyl] trimethoxysilane (MGO) into waterborne epoxy, exhibited excellent corrosion resistance and slight harm of solvent-based coating to the environment. The MGO displayed perfect dispersion and corrosion resistance, which reduced the aggregation of graphene oxide (GO) due to the coupling of functional groups. After modification, the lamellar structure of GO remains unchanged, and the interlayer spacing was increased. Crosslinking with resin to form a “labyrinth structure” corrosion path in the coating. Furthermore, the conductivity of GO decreased after the insertion of functional groups. The results demonstrated that the composite with a 0.5 wt.% content of MGO presented remarkably improved corrosion resistance with a protection efficiency (PE) of 99.7%.

A Design Method for Labyrinth Sound Absorption Structure with Micro-perforated Plates

A kind of labyrinth sound absorption structure is constructed by embedding multi-layer micro-perforated plates into a pipeline, and a design method is proposed to optimize its parameters to ensure a good sound absorption performance. First, the effects of parameters of the labyrinth structure on the sound absorption performance are investigated. Second, a parameter optimization method is constructed based on the acoustic impedance transfer analysis and particle swarm optimization algorithm. Then, a simulation experiment is implemented by means of COMSOL to verify the optimization results. Finally, the labyrinth structures with straight pipeline, spiral pipeline and parallel pipeline are designed and their sound absorption performances are evaluated and compared. The research shows that, the effects of the perforation diameter, the plate thickness, and the perforation rate on the sound absorption performance are non-independent while the effect of the depth of cavity is independent; the weighting coefficient in the parameter optimization method could be adjusted to ensure a big absorption bandwidth in a low frequency range; in the frequency range of 30-4000 Hz, the labyrinth structure with straight pipeline and the labyrinth structure with spiral pipeline have the same sound absorption performance; for the labyrinth structure with parallel pipeline, the inner corner radius of pipeline has a great influence on the sound absorption performance, and the radius should be greater than 20mm.

Dose-dependent structural and immunological changes in the placenta and fetal brain in response to systemic inflammation during pregnancy.

Systemic maternal inflammation is associated with adverse neonatal sequelae. We tested the hypothesis that IL-1β is a key inflammatory regulator of adverse pregnancy outcomes. Pregnant mice were treated with intraperitoneal injections of IL-1β (0, 0.1, 0.5, or 1μg) from embryonic day (E)14 to E17. Placenta and fetal brains were harvested and analyzed for morphologic changes and IL-1β signaling markers. As compared with non-treated dams, maternal injections with IL-1β resulted in increased p-NF-κB and caspase-1 in placentas and fetal brains, but not consistently in spleens, suggesting induction of intrinsic IL-1β production. These findings were confirmed by increased levels of IL-1β in the placentas of the IL-1β-treated dams. Systemic treatment of dams with IL-1β suppressed Stat1 signaling. Maternal inflammation caused by IL-1β treatment reduced fetal viability to 80.6% and 58.9%, in dams treated with either 0.5 or 1μg of IL-1β, respectively. In the placentas, there was an IL-1β dose-dependent distortion of the labyrinth structure, decreased numbers of mononuclear trophoblast giant cells, and reduced proportions of endothelial cells as compared to placentas from control dams. In fetal brains collected at E17, there was an IL-1β dose-dependent reduction in cortical neuronal morphology. This work demonstrates that systemic IL-1β injection causes dose-dependent structural and functional changes in the placenta and fetal brain.

Double-label immunohistochemistry to assess labyrinth structure of the mouse placenta with stereology

In mice, the labyrinth zone of the placenta exchanges nutrients and gases between mother and fetus. This placental zone is complex in structure and defects in its morphogenesis can compromise substrate exchange and thus, fetal growth and viability. Numerous mouse models involving genetic and environmental manipulation show abnormalities in labyrinth zone size. However, further structural analysis, normally undertaken using ultrathin resin sections, can pose practical constraints. Here, we validate the use of stereology on paraffin-embedded sections double-labelled for lectin and cytokeratin as a cheap, fast and robust alternative for analysing the structure of the mouse placental labyrinth.

The antithrombin binding regions of heparin mediate fetal growth and reduced placental damage in the RUPP model of preeclampsia†.

Preeclampsia is a serious hypertensive disorder of pregnancy, which is only cured with delivery of the placenta, thereby commonly necessitating preterm birth of the fetus. Low-molecular-weight heparin (LMWH) has demonstrated potential to reduce the incidence of preeclampsia in high-risk pregnant women, although the underlying mechanism by which LMWH protects against preeclampsia is unknown. Given the complex structure and biologic actions of heparin, we tested the hypothesis that heparin can mediate preeclampsia prevention via nonanticoagulant pathways. We compared the effects of a nonanticoagulant, glycol-split LMWH (gsHep)—rendered nonanticoagulant through disruption of the antithrombin binding regions—with the LMWH dalteparin in the rat reduced uterine perfusion pressure (RUPP) surgical model of preeclampsia. Although RUPP animals exhibit significantly elevated blood pressure and reduced plasma levels of placental growth factor (PGF) compared to sham, neither dalteparin nor gsHep treatment significantly impacted these parameters. However, the observed positive correlation between PGF levels and number of viable fetuses in RUPP-induced animals suggests that reduced PGF levels were predominately due to placental loss. Daily subcutaneous injections of low-dose dalteparin but not gsHep significantly restored fetal growth that was impaired by RUPP surgery. Placentas from RUPP animals exhibited an abnormal labyrinth structure, characterized by expanded sinusoidal blood spaces, relative to sham-operated animals. Morphometric analysis demonstrated that dalteparin but not gsHep treatment normalized development of the labyrinth in RUPP-exposed conceptuses. These data suggest that the antithrombin-binding regions of LMWH are required to confer its protective effects on fetal growth and placental development.

Hydraulic and turbulence structure of triangular labyrinth weir‐pool fishways

AbstractDetailed laboratory experiments were conducted to analyze and evaluate a new weir‐pool fishway design. The new design consisted of a series of one‐cycle, triangular labyrinth weirs that formed a weir‐pool fish passage. Hydraulic characteristics of flow over the proposed fishway were examined for three pool lengths and a wide range of discharges. It was found that the new design had superior discharge capacity over classical weir‐pool fishways in plunging flow regime. Spatial and point analyses of measured velocity data were carried out to understand turbulence structure and distribution of turbulent flow. The power dissipation per unit volume was calculated for different tests, and it varied nonlinearly with discharge. Based on the limiting criteria for energy dissipation rates of different fish species, the maximum operating discharge for different slopes was extracted for the proposed design. The model‐to‐prototype scaling analysis was performed based on the recommended scaling factor of three for prototype. It was found that the approach velocity of prototype increased by 12%, whereas the total discharge increased by more than five times. The contour plots of time‐averaged velocity indicated that the proposed fishways offered diversified flow fields without exceeding the maximum velocity above the standards recommended for weir‐pool fishways. To study the size, direction, and periodicity of turbulent eddies, magnitude of the most energetic eddy and dominant frequencies were extracted using power spectrum analysis. Quadrant analysis consistently showed that Reynolds shear stresses in ejection and sweep events became weaker as the pool length increased. The small region of strong ejection and sweep events evidenced a good resting place for fish migration, whereas the generated turbulence was large enough to attract fish species to use the passage.

Labyrinth structure sealing performance on grounding device of railway passenger vehicles

In this paper, the function of isolating carbon powder and water in the labyrinth structure on Grounding Device of Railway Passenger Vehicles is studied. The possibility of carbon powder and water entering the bearing through the labyrinth structure under the condition of seal failure of the grounding device is analyzed.

Numerical and Experimental Investigation of the Sealing Effect of a Specific Labyrinth Seal Structure

A numerical simulation and experimental study were performed to investigate the sealing effect of the labyrinth seal used in a wheel-side reducer. A three-dimensional computational fluid dynamics model was established based on the labyrinth structure. The effects of the temperature and viscosity of lubricant, rotor speed, pressure ratio, clearance, and cavity size of the sealing structure on the sealing were analyzed, and the leakage amount under the corresponding values of different factors was also analyzed. The results indicated that increase in the lubricating oil temperature, viscosity, pressure ratio, and seal clearance lead to decrease in the sealing effect and increases in the leakage. And the effect of rotational speed on the seal is low. To verify numerical simulation, the results of numerical analysis, a test bench was set up to simulate the work of the reducer, and the sealing effect of the sealing structure was examined. The simulation result was compared with the actual results. Both the numerical simulation and experiment indicate that the labyrinth seal achieves the desired sealing effect.

Remodeling of the Basal Labyrinth of Retinal Pigment Epithelial Cells With Osmotic Challenge, Age, and Disease.

PurposeThe basal surface of the retinal pigment epithelium (RPE) is folded into a complex basal labyrinth thought to facilitate solute and water transport. We aimed to analyze and define the structural organization of the basal labyrinth of the RPE to enable quantitative analysis of structural changes in age and disease and to better understand the relationship between basal labyrinth structure and efficiency of transepithelial transport.MethodsConventional transmission and serial block-face scanning electron microscopy and electron tomography were used to examine the structure of the basal labyrinth in mouse eyes of different ages and genotypes and with and without osmotic shock before fixation.ResultsWe identified structurally distinct zones (stacked and ribbon-like) within the RPE basal labyrinth that are largely organelle free and cisternal elements that make contact with the endoplasmic reticulum (ER) and mitochondria. These zones are lost in a hierarchic fashion with age and prematurely in a model of the progressive retinal degenerative disease, choroideremia. Junctional complexes crosslink closely opposed infoldings. Spacing between the basal infoldings was affected by subtle osmotic changes while osmotic shock induced dramatic remodeling of the infoldings.ConclusionsThe basal labyrinth has complex but ordered structural elements that break down with age and in choroideremia. The geometry of these elements and site of contact with ER and mitochondria likely facilitate the ion transport that drives water transport across the basal RPE surface. Changes in structure in response to local osmotic variation may allow transport to be modulated in order to maintain RPE volume.

The Anatomy of Respiratory Organ of Climbing Perch (Anabas testudineus)

The study aims to find out about the anatomical and histological structure of gill organ and labyrinth in Anabas Testudineus. The organ used is gill and labyrinth of climbing perch. The histological observation is done by making the histological preparation applied to a Hematoxylin-Eosin staining. The result of this study shows that the anatomical gill of climbing perch consists of the gill filaments and gill rakers attaching to the gill arch and the cartilage fold which are shaped like a rose. Then, the histological observation of climbing perch gill consists of the gill filament and gill arch. The gill arch is composed of gill rakers, mucosal epithelium, adipose tissue, basal membrane, mucous cell, submucosa, artery, and bone tissue. The gill filament consists of primary and secondary lamella. Primary lamella is composed of cartilage coated by perichondrium, central venous sinus, chloride cell, while secondary lamella is composed of squamous epithelium cell, mucous cell, pillar cell, and erythrocyte. Labyrinth is made up of adipose tissue, elastic cartilage, perichondrium, epithelium, blood vessel, connective tissue, and mucous cell.

Discharging Performance in Length of Hard Labyrinth and Pressure of Cylinder Type Drip Irrigation Hose

The performance of drip irrigation devices depends on flow uniformity related to the function of pressure compensation. The flow uniformity can be secured when the internal fluid pressures at the positions of the flow holes are maintained uniformly. The pressure compensation effect of the drip irrigation devices can be optimized with the combination of soft silicon and labyrinth structures. However, for a drip irrigation devices composed of only hard labyrinth structures, the flow rate is changed largely with the length and the internal geometry of the labyrinth structure. Although a drip irrigation devices with only hard labyrinth structures can be fabricated simply, the changes of flow rates with internal fluid pressures are much larger than those of the drip irrigation devices with soft silicon. Because the drip irrigation devices with only labyrinth structures can be utilized widely through the optimization of the fluid pressure, the length of the structures, and the cross-sectional area of them, the study on the optimization can play an important role for enhancing the performance of the drip irrigation devices. In this study, experimental and numerical studies for investigating the performance of the drip irrigation devices had been conducted. In the experiments and numerical calculations(CFD), the variable parameters were the lengths of the labyrinth structures(#1~#8) and the fluid pressures(0.5~3.0 bar).

A rigid acoustic metamaterial with phase modulation and power attenuation

We introduced a rigid structure into the acoustic metasurface design, proposed labyrinth structure based on the equivalent medium theory and different media are replaced by curly labyrinth. Layered medium theory and equivalent medium theory are combined to design arbitrary acoustic metasurface structure. An acoustic metasurface studied in this paper and realised simultaneous phase modulation and power attenuation in the air, the effective range covered from 30 to 90 degrees, and power attenuation is over 40%. According to layered medium theory which could modulate acoustic wave direction, the metasurface with same function can also be applied to underwater. Its related simulation results are calculated by FEA method. Finally, by introducing the curly labyrinth theory, the underwater acoustic metasurface with simultaneous phase modulation and power attenuation is designed and verification. This paper potential applications in the rigid underwater acoustic metasurface in low frequency, adjustable direction, and sound attenuation.

The vertebrate middle and inner ear: A short overview.

The evolution of the various hearing adaptations is connected to major structural changes in nearly all groups of vertebrates. Besides hearing, the detection of acceleration and orientation in space are key functions of this mechanosensory system.The symposium “show me your ear – the inner and middle ear in vertebrates” held at the 11th International Congress of Vertebrate Morphology (ICVM) 2016 in Washington, DC (USA) intended to present current research addressing adaptation and evolution of the vertebrate otic region, auditory ossicles, vestibular system, and hearing physiology. The symposium aimed at an audience with interest in hearing research focusing on morphological, functional, and comparative studies. The presented talks and posters lead to the contributions of this virtual issue highlighting recent advances in the vertebrate balance and hearing system. This article serves as an introduction to the virtual issue contributions and intends to give a short overview of research papers focusing on vertebrate labyrinth and middle ear related structures in past and recent years.

An acoustic metasurface with simultaneous phase modulation and energy attenuation

We introduced a rigid structure into the acoustic metasurface design, the proposed labyrinth structure is based on the equivalent medium theory and different media are replaced by curly labyrinth. Layered media theory and equivalent medium theory are combined to design the arbitrary acoustic metasurface structure. An acoustic metasurface studied in this paper realized simultaneous phase modulation and energy attenuation in the air, the effective phase modulation range covered from 30[Formula: see text] to 90[Formula: see text] and the energy attenuation is over 40%. According to layered media theory which could modulate the acoustic wave direction, the metasurface with same function can also be applied to underwater case. Corresponding simulation results are calculated by FEA. Finally, by introducing the curly labyrinth theory, the underwater acoustic metasurface with simultaneous phase modulation and energy attenuation is designed and verified. This paper has potential applications in rigid underwater acoustic metasurface designs with low frequency, adjustable direction and sound energy attenuation.

Les Sens du quotidien, l’essence du quotidien. Désordre de Philippe De Jonckheere

Désordre, a website that Philippe De Jonckheere has been developing and maintaining for over seventeen years (since 2000), is a hypermediatic work, composed of numerous projects, with a labyrinthic structure characterized by semiotic hybridization and transartiality, in a context oscillating between the autobiographic and the autofictional. It reenacts the diaristic practice by summoning, through its digital anchoring, text, images, videos, and sounds. This analysis aims to highlight how the polyphonic work of De Jonckheere allows seeing, reading, and, above all, feeling the everyday life experience and, through it, the sensory experience in its plurality. I will underline the way in which this experience adheres to the logic of accumulation, of deepening of the real—of the relationship to the world and life—shifted towards the capture of the short-lived, the detail, if not the anecdotal. In addition, this article will examine how the work of De Jonckheere gives rise to a rearrangement of time, working on what could be called a ‘pathetic temporality.’ In short, I will highlight the way in which Désordre, which engages and exalts the not-so-much, the almost nothing, falls within the reengagement of the sensitive, as much intimate as extimate.

Double-split labyrinth resonator with defective ground system for wide-band band-stop filter application

A labyrinth resonator with defective ground structure (DGS) is introduced for designing a wide-band band-stop filter in order to adjust the resonating characteristics by varying the dimension of the structure to cover 2.75 – 10.30 GHz. A series of modified double-split ring resonators (DSRRs) are embedded into a 50Ω microstrip framework to attain a labyrinth structure. The Rogers RO- 3010, which has a succinct structure, is used as the substrate in the proposed wide-band band-stop filter. The realization of the architecture is explored both integrally and experimentally, and a complementary split ring resonator (CSRR) is introduced in the ground layer. The level of rejection of the filter in the stop-band region increases with the introduction of the CSRR. In addition, the filter is evaluated by applying the Nicolson-Ross-Weir approach at the filtering frequency. The effective electromagnetic parameters retrieved from the simulation of the S-parameters imply that the metamaterial structure exhibits negative refraction bands. With a promising design and wide range of double-negative characteristics, we propose a new type of filter which is suitable for a wide-band band-stop application.

Shutdown Dose Rate Calculation for the Preliminary Concept of K-DEMO Equatorial Port Area

This paper presents a shutdown dose rate (SDR) calculation to estimate a newly developed preliminary concept of the equatorial port model for the Korean fusion demonstration reactor (K-DEMO). The equatorial port model was designed to provide effective radiation shielding abilities adopting the port shielding block and labyrinth structure, which was integrated into the modified K-DEMO neutronic analysis model by the Monte Carlo automatic modeling system. A rigorous two-step method was applied to couple transport (MCNP) and activation (FISPACT) codes according to three steps of calculation procedures. The results of neutron flux and decay gamma transport calculation for the equatorial port area have been indicated in this paper. The SDR calculation result near the equatorial port area reveals that a dose level in the equatorial port interspace was below $100~\mu $ Sv/h after 12 days of the shutdown. Shielding blocks and two labyrinth structures prove that they effectively attenuate neutrons on the current concept of the equatorial port model.

Maze or Labyrinth: Identifying PTSD Stressors in the Built Space of Zaatari and Calais Refugee Camps

In this study, we analyze the structure of paths within two refugee camps (Calais, France, and Zaatari, Jordan) as a preliminary study examining posttraumatic stress disorder (PTSD) stressors within such camps. We do so through a geospatial analysis of intersections and viewsheds within the camps. Given that anxiety, and the avoidance associated with it, is a primary characteristic of PTSD, refugees might prefer built environments with fewer stressors or anxiety triggers. This study provides a baseline for analyzing basic stressors in a way to test whether design supports anxiety-based avoidance. The planned structure of Zaatari shows a high prevalence of spatial PTSD stressors with lower visibility and a more maze-like structure than that of Calais. This suggests a coping strategy taken by refugees to produce a more suitable and less stressing labyrinth structure. To properly treat PTSD in geographical space, we suggest a need for consideration of this in the planning, function, and very existence of refugee camps and settlements.