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Porokeratosis is a skin condition that involves the formation of plaques, characterized by a hyperkeratotic ridge with an atrophic center. There is a histological presence of a cornoid lamella, which is a parakeratotic column that traverses through the stratum corneum. The plaques are mostly benign but have the potential to become squamous cell carcinomas if left untreated. Porokeratosis lesions typically occur on the extremities, but they can develop anywhere. The occurrence of porokeratosis on the lip is exceedingly rare. We report three cases of porokeratosis on the lip. Each incidence was treated with cryotherapy, which was unsuccessful in two. One of these two patients did not elect for topical treatment and is being monitored for lesion changes. The second patient was successfully treated via shave biopsy. The third patient was lost to follow-up post-cryotherapy.

High-density polyethylene (HDPE)/Fe3O4 composites with Fe3O4 nanofiller contents of ω = 1, 3, and 5 vol % have been obtained by hot pressing of a homogeneous mixture of HDPE and a synthesized Fe3O4 nanopowder. The structure and thermal properties of the HDPE/Fe3O4 nanocomposites have been studied; it has been found that, with an increase in the Fe3O4 nanoparticle concentration in the polymer matrix, the morphology of the supramolecular structure of the HDPE matrix drastically changes. It has been established that, with an increase in the nanofiller concentration, the mobility of macromolecular chains in the matrix and the crystalline lamellae thickness decrease. Nanoparticles disrupt the regularity of lamellae in the crystalline phase of the polymer matrix and prevent the formation and growth of new crystalline domains in the amorphous region. [ABSTRACT FROM AUTHOR]

The decades-long paradigm of continuous and perpetual lamellar twisting constituting banded spherulites has been found to be inconsistent with several recent studies showing discontinuity regions between consecutive bands, for which, however, no explanation has been found. The present research demonstrates, in three different semicrystalline polymers (HDPE, PEG10000 and Pluronic F-127), that sequential transcrystallinity is the predominant mechanism of banded spherulite formation, heterogeneously nucleated on intermittent self-shear-oriented amorphous layers excluded during the crystals' growth. It is hereby demonstrated that a transcrystalline layer can be nucleated on amorphous self-shear-oriented polymer chains in the melt, by a local melt flow in the bulk or in contact with any interface—even in contact with the interface with air, e.g., in contact with an entrapped air bubble or at the edges of the sample—or nucleated following the multiple directions and orientations induced by a turbulent flow. The bilateral excessive local exclusion of amorphous non-crystallizable material, following a short period of initial non-banded growth, is found to be the source of dislocations leading to spirally banded spherulites, through the transcrystalline layers' nucleation thereon. The present research reveals and demonstrates the sequential transcrystalline morphology of banded spherulites and the mechanism of its formation, which may lead to new insights in the understanding and design of polymer processing for specific applications. [ABSTRACT FROM AUTHOR]

The present study elucidates the role of annealing with electric field on lamellar crystalline structure and molecular orientation of polymer chains in ferroelectric copolymer (P(VDF‐TrFE)) and ferroelectric terpolymer (P(VDF‐TrFE‐CFE)) spin‐coated thin films. The ferroelectric polymer thin films annealed under an electric field support the growth of nanostructure with an “edge‐on” lamellar crystalline structure having in‐plane molecular chain orientation. The poled P(VDF‐TrFE) thin films have higher remnant polarization (Pr) ≈6.2 µC cm−2 and saturation polarization (Ps) ≈8.2 µC cm−2 at an applied electric field of 250 MV/m compared to unpoled thin films having Pr ≈4.7 and Ps ≈6.2 µC cm−2. Also, poled P(VDF‐TrFE) thin films show lower coercive field (Ec) ≈94 MV/m compared to an unpoled thin film having Ec ≈105 MV/m. Similarly, poled PVDF‐TrFE‐CFE thin film shows better ferroelectric properties having Pr ≈0.4 and Ps ≈5.7 µC cm−2 at an applied electric field of 200 MV m−1 compared to unpoled thin films having Pr ≈0.4 and Ps ≈4.1 µC cm−2. The storage energy efficiency of unpoled and poled P(VDF‐TrFE‐CFE) thin films is measured to be ≈75% and 80%. Annealing of ferroelectric P(VDF‐TrFE) polymer thin films under an electric field demonstrates improved ferroelectric and electroactive properties. [ABSTRACT FROM AUTHOR]

Abstract This research is based on computational fluid dynamics simulations of water and microbubble flow within the tank of a lamellar DAF (L-DAF) clarification system operating under high-rate DAF conditions (12–30 m/h). Firstly, performance of the DAF tank with lamellae was evaluated under two operating conditions in which the flow was either short-circuited or stratified in the absence of lamellae. In addition, the improvement in bubble removal efficiency achieved by the incorporation of lamellae in each scenario was assessed. Secondly, an in-depth analysis was conducted of the flow that develops in the separation zone as a result of placing the lamella pack in that part of the tank. The significant density difference that the lamellae cause to exist between the bubble blanket and clarified water below is responsible for the complex three-dimensional flow observed between the two regions. Analysis of this flow showed a previously undescribed mechanism in which the density gradient plays a crucial role in preventing bubbles from passing through the lamellae and ultimately escaping with the effluent. Finally, the effect of hydraulic loading on the bubble removal efficiency of the L-DAF tank under consideration was researched, and it was found that an L-DAF with a height/length ratio of 0.72 is able to operate at hydraulic loading close to 30 m/h, evidencing good debubbling performance.

Investigating fatigue failure in titanium alloys is crucial for material design and engineering. Fatigue behavior in dual‐phase titanium alloys is strongly correlated with microstructural features and microdefects. This work formulates an improved modeling method to investigate fatigue behavior of bimodal Ti–6Al–4V, emphasizing the effects of lamellar orientation and microdefects. Using an improved Voronoi tessellation method, we establish representative volume element (RVE) models with various grain size distributions. Crystal plasticity finite element modeling (CPFEM) is used to analyze fatigue deformation in bimodal Ti–6Al–4V, considering microdefects and lamellar orientation. Fatigue indicator parameters are then incorporated into CPFEM to predict fatigue life and verified with experimental data. Numerical results highlight the significant influence of lamellar orientation and microdefects on fatigue behavior, with predicted life within the 3‐error band. This method efficiently overcomes challenges in quantitatively characterizing microstructural lamellae that experiments are short of, paving the way for designing fatigue‐resistant alloy materials with similar microstructures. Highlights: The proposed method effectively addresses the effects of lamellar orientation and microdefects.The improved VT modeling can reflect grain size distribution in bimodal Ti–6Al–4V.CPFEM‐based modeling method achieves acceptable fatigue life prediction accuracy. [ABSTRACT FROM AUTHOR]

This research is based on computational fluid dynamics simulations of water and microbubble flow within the tank of a lamellar DAF (L-DAF) clarification system operating under high-rate DAF conditions (12–30 m/h). Firstly, performance of the DAF tank with lamellae was evaluated under two operating conditions in which the flow was either short-circuited or stratified in the absence of lamellae. In addition, the improvement in bubble removal efficiency achieved by the incorporation of lamellae in each scenario was assessed. Secondly, an in-depth analysis was conducted of the flow that develops in the separation zone as a result of placing the lamella pack in that part of the tank. The significant density difference that the lamellae cause to exist between the bubble blanket and clarified water below is responsible for the complex three-dimensional flow observed between the two regions. Analysis of this flow showed a previously undescribed mechanism in which the density gradient plays a crucial role in preventing bubbles from passing through the lamellae and ultimately escaping with the effluent. Finally, the effect of hydraulic loading on the bubble removal efficiency of the L-DAF tank under consideration was researched, and it was found that an L-DAF with a height/length ratio of 0.72 is able to operate at hydraulic loading close to 30 m/h, evidencing good debubbling performance. [ABSTRACT FROM AUTHOR]

Neuroepithelial cells (NECs) within the fish gill contain the monoamine neurochemical serotonin (5-HT), sense changes in the partial pressure of oxygen (PO2) in the surrounding water and blood, and initiate the cardiovascular and ventilatory responses to hypoxia. The distribution of neuroepithelial cells (NECs) within the gill is known for some fish species but not for the Gulf toadfish, Opsanus beta, a fish that has always been considered hypoxia tolerant. Furthermore, whether NEC size, number, or distribution changes after chronic exposure to hypoxia, has never been tested. We hypothesize that toadfish NECs will respond to hypoxia with an increase in NEC size, number, and a change in distribution. Juvenile toadfish (N = 24) were exposed to either normoxia (21.4 ± 0.0 kPa), mild hypoxia (10.2 ± 0.3 kPa), or severe hypoxia (3.1 ± 0.2 kPa) for 7 days and NEC size, number, and distribution for each O2 regime were measured. Under normoxic conditions, juvenile toadfish have similar NEC size, number, and distribution as other fish species with NECs along their filaments but not throughout the lamellae. The distribution of NECs did not change with hypoxia exposure. Mild hypoxia exposure had no effect on NEC size or number, but fish exposed to severe hypoxia had a higher NEC density (# per mm filament) compared to mild hypoxia-exposed fish. Fish exposed to severe hypoxia also had longer gill filament lengths that could not be explained by body weight. These results point to signs of phenotypic plasticity in these juvenile, lab-bred fish with no previous exposure to hypoxia and a strategy to deal with hypoxia exposure that differs in toadfish compared to other fish. [ABSTRACT FROM AUTHOR]

The decades-long paradigm of continuous and perpetual lamellar twisting constituting banded spherulites has been found to be inconsistent with several recent studies showing discontinuity regions between consecutive bands, for which, however, no explanation has been found. The present research demonstrates, in three different semicrystalline polymers (HDPE, PEG10000 and Pluronic F-127), that sequential transcrystallinity is the predominant mechanism of banded spherulite formation, heterogeneously nucleated on intermittent self-shear-oriented amorphous layers excluded during the crystals’ growth. It is hereby demonstrated that a transcrystalline layer can be nucleated on amorphous self-shear-oriented polymer chains in the melt, by a local melt flow in the bulk or in contact with any interface—even in contact with the interface with air, e.g., in contact with an entrapped air bubble or at the edges of the sample—or nucleated following the multiple directions and orientations induced by a turbulent flow. The bilateral excessive local exclusion of amorphous non-crystallizable material, following a short period of initial non-banded growth, is found to be the source of dislocations leading to spirally banded spherulites, through the transcrystalline layers’ nucleation thereon. The present research reveals and demonstrates the sequential transcrystalline morphology of banded spherulites and the mechanism of its formation, which may lead to new insights in the understanding and design of polymer processing for specific applications.

Polymer semiconductors frequently form crystals or mesophases with lamellae, that comprise alternating layers of stacked backbones and side chains. Controlling lamellar orientation in films is essential for obtaining efficient charge carrier transport. Herein, lamellar orientation is investigated in an application‐relevant setup: lamellae assembled on a substrate that strongly favors face‐on orientation, but exposed to a film surface that promotes orientation along an "easy" direction, other than face on. It is assumed that the face‐on order propagates from the substrate, but the lamellae bend to reduce their surface energy. A qualitative free‐energy model is developed. The deformation is investigated as a function of film thickness, effective Young modulus, anchoring coefficient, and easy direction at the free surface. The calculations highlight the importance of elastic constants – lamellae can substantially deform already when Young moduli are only an order of magnitude smaller than the values that are reported for crystals. Softer Young moduli are expected when lamellar assembly occurs in a non‐solidified mesophase that can be an equilibrium or (more speculatively) a transient state prior to crystallization. The alternative scenario of a two‐layered film is also evaluated, where edge‐on and face‐on grains form, respectively, at the free surface and substrate. [ABSTRACT FROM AUTHOR]

Thin lamellae, corresponding to the layer components of structural glued members, i.e., 2-ply or 3-ply glued flooring, can be manufactured in re-sawing operations of kiln-dried wood blocks or in wet technologies, which currently seem to be more common because of the shorter drying time. The re-sawing process in wet technology is conducted on dedicated thin-cutting band sawing machines with stellite-tipped band saws. The goal of this research was to demonstrate the capacity of surface production (m2/ tool life) of visible layers of oak engineered flooring composites in a function of both a new band saw and a re-sharpened band saw blade. Additionally, the state of teeth of each band saw blade was examined at the end of the tool life. A series of cutting tests were performed in sawmill production conditions. The conducted tests revealed that a three times higher capacity of surface production was obtained for the new tool compared to re-sharpened tool. Additional microscopic observations of some re-sharpened teeth showed deformed plastic characteristics.

The micro- and sub-microstructures of human cortical bone are analytically investigated in this study. Modified equations are derived as a function of sub-microstructural architectures and volumetric bone mineral density (BMD) in order to estimate the nine orthotropic elastic constants of cortical bone at sub-microlevel. In general, the analytical models contain fanning or oscillating plywood layup at the lamella level are in good agreement with the results of nanoindentation tests, and the osteon models contain combinations of twisting/oscillating or unidirectional/fanning lamellar patterns are in agreement with the experimental results of direct tensile and punching shear tests on a single osteon. [ABSTRACT FROM AUTHOR]

The influence of polytetrafluoroethylene (PTFE) processing in sc-CO2 and sc-PFO above the melting point on the microstructure and characteristics of phase transitions is studied using high-resolution scanning electron microscopy and differential scanning calorimetry (DSC). It is shown that, depending on the crystallization conditions, after the processing of PTFE in the supercritical fluid, the formation of a microstructure with a radial orientation of fibrils atypical for this polymer is possible. The processing of PTFE in the supercritical fluid leads to an irreversible increase in the heat of melting and crystallization and, accordingly, to an increase in the degree of crystallinity by 1.5–2 times compared to the initial values. The growth in the crystallinity is explained by a change in the microstructure of the PTFE melt in the supercritical fluid: the release of a part of segments of macromolecules from physical knots during the process of swelling and plasticization of the polymer matrix. Disentanglement of such knots that limit molecular mobility contributes to an increase in the number of macromolecular units involved in the formation of crystalline domains and to an irreversible increase in the degree of crystallinity. [ABSTRACT FROM AUTHOR]

In situ microfibrillar PA6/PLA composites (MFCs) with high strength and toughness were produced via a multistage stretching extrusion system. The PA6 microfibrils induced the growth of PLA crystals perpendicular to the PA6 microfibrils and significantly enhanced the mechanical properties of the MFCs. Notably, the PLA-9 sample with 9 wt% PA6 microfibrils achieved excellent tensile strength and elongation at break (79.1 MPa and 77.8 %, respectively), which were 1.3 and 13.4 times than those of neat PLA. During the tensile process, the PA6 microfibrils underwent plastic deformation accompanied by the detachment and fragmentation of the PLA lamellae. The formation of shish-kebab structure significantly improved the tensile strength and elongation at break of in situ microfibrillar PA6/PLA composites. [Display omitted] • The MFCs achieved significantly improve in tensile strength and elongation at break. • The formed PLA crystal was the classic shish-kebab structure. • The tensile stress can be effectively transferred from the matrix to the PA6 microfibrils. • The PLA lamellae underwent detachment and fragmentation during the tensile process. [ABSTRACT FROM AUTHOR]

Lamellae are sheets of mineralized collagen 1–20 µm thick, extending over hundreds of µm in bone tissue, occupying bone's structural hierarchy at a level above collagen fibres and osteocytes, and below osteons and trabeculae. Osteons are tubular arrangements of lamellae surrounding central neurovascular canals. Lamellae in osteons are usually described as concentric cylinders based on their annular appearance in transverse section. In this review, I provide a perspective on current understanding of the relationship between geometry of the bone formation front and the shape of lamellae produced at it, reaching the conclusion that the ‘closing cone’ bone formation front in secondary osteonal remodelling must necessarily result in cone-shaped lamellae in the mature secondary osteon. Secondary osteons replace primary osteons through a tunnelling process of bone turnover, meaning that conical lamellae may become more common in older and damaged bone which is at greatest risk of fracture. Visualization and measurement of three-dimensional lamellar shape over hundreds of microns is needed to provide data for accurate micromechanical simulations. Treating secondary osteonal lamellae as a ‘stack of cones’ rather than ‘nested cylinders’ may have important implications for our appreciation of bone's function as a load-bearing tissue and of its behaviour in fracture.

Properties of the Voronoi tessellations arising from random 2D distribution points are reported. We applied an iterative procedure to the Voronoi diagrams generated by a set of points randomly placed on the plane. The procedure implied dividing the edges of Voronoi cells into equal or random parts. The dividing points were then used to construct the following Voronoi diagram. Repeating this procedure led to a surprising effect of the positional ordering of Voronoi cells, reminiscent of the formation of lamellae and spherulites in linear semi-crystalline polymers and metallic glasses. Thus, we can conclude that by applying even a simple set of rules to a random set of seeds, we can introduce order into an initially disordered system. At the same time, the Shannon (Voronoi) entropy showed a tendency to attain values that are typical for completely random patterns; thus, the Shannon (Voronoi) entropy does not distinguish the short-range ordering. The Shannon entropy and the continuous measure of symmetry of the patterns demonstrated the distinct asymptotic behavior, while approaching the close saturation values with the increase in the number of iteration steps. The Shannon entropy grew with the number of iterations, whereas the continuous measure of symmetry of the same patterns demonstrated the opposite asymptotic behavior. The Shannon (Voronoi) entropy is not an unambiguous measure of order in the 2D patterns. The more symmetrical patterns may demonstrate the higher values of the Shannon entropy. [ABSTRACT FROM AUTHOR]

The human cornea is thicker in the periphery than the center and it has been suggested that this must be due to greater numbers of lamellae in the peripheral corneal stroma. The purpose of this study was to use high-resolution ultrastructural imaging to determine if the greater thickness of the peripheral cornea is due to the presence of more lamellae or if there is some other anatomical explanation. In this study, full thickness corneas from three human donors were processed for light microscopy (LM) and transmission electron microscopy (TEM). Images were taken in three distinct stromal regions (anterior, middle, and posterior) from the central and peripheral cornea. Stromal thickness was evaluated by LM while TEM was used to evaluate numbers and thicknesses of lamellae, mean collagen fibril diameter, and mean collagen fibril density. Mean stromal thickness was significantly thinner in the central (415 ± 34 µm) compared to the peripheral (536 ± 29 µm) cornea (P = 0.009). Numbers of lamellae were not significantly different between central (246 ± 14) and peripheral (251 ± 14) cornea. Average lamellar thickness was not different across all regions of the cornea, except for the peripheral posterior where the lamellae were approximately 50 % thicker (P < 0.05). Collagen fibril diameters were larger in the peripheral cornea by approximately 30 % when compared to the central cornea, in all regions (P < 0.01). This study shows that it is an increase peripheral posterior lamellar thickness, rather than an increase in the number of lamellae, that accounts for the increase in corneal stromal thickness in the periphery of the human cornea. While collagen fibril diameters are greater throughout the peripheral stroma, the lamellae in the mid and anterior peripheral stroma are not thicker than centrally. [ABSTRACT FROM AUTHOR]

In this article, a comparative analysis of the occurrence of pathologies of the gills and liver of carp and pike perch living in Lake Balkhash was carried out. To achieve the goal of the work, a histological, morphometric and statistical study of the tissues of the gills and liver of the studied fish specimens was carried out. In the liver of carp and zander, fatty degeneration, polymorphism of nuclei, proliferation of Kupffer cells, disturbances of the microcirculatory bed were revealed, and the following pathological processes were observed in the structure of the gills: a change in the shape of secondary lamellae, hyperplasia of the gill epithelium, necrosis and edema of the respiratory epithelium, as well as foci of hemorrhages. In most of the studied individuals, pathologies of both organs were noted simultaneously. Liver pathologies were found in 61.45% of carp and 69.62% of zander. Histological disturbances in the structure of the gills were recorded in 70.73% of carp and 61.25% of zander. The number of fish without violations of the structure of the gills and liver was 9.28% among carp and 8.37% in zander. The detected pathologies in the histological structures of the gills and liver of fish indicate the impact of various adverse factors on the ecosystem of Lake Balkhash. [ABSTRACT FROM AUTHOR]

The study aimed to evaluate the effects of Effective microorganisms (EM) on C.carpio by studying their effect on some growth and health Parameters. The study dealt with the calculation of weekly and total weight gain, food conversion and Somatic index. The Miocromorphometric parameters, including Goblet cells, length of both villus of intestine and gills (primary and secondary) lamellae were also studied. Also estimation titer count of Lactic acid bacilli in the intestine. The results showed that there were significant differences at P=0.05 between the control group and the EM treated group, and this difference was clear on the weekly and total weight gain, the effect was reflected on the organs weights represented by the liver, gills, anterior kidneys, posterior kidneys, intestines and spleen, miocromorphometric study showed that there is a significant increase of villus lengths and primary and secondary lamellae for EM treated group, and this effect was withdrawn on the number of goblet cells present in the intestinal epithelium, a very significant increase in the mean number of lactic acid bacilli was recorded in the EM treated groups. The use of effective organisms is a useful strategy that has a clear impact on growth and health parameters in fish. [ABSTRACT FROM AUTHOR]

Herein, it is determined that the stress response of stacked microlamellae to tensile deformation along the normal direction depends on the lateral size of the lamellae. Lamellae with different lengths are formed by B5‐29‐EMA‐φ block copolymers (BCPs) comprising poly(ethyl methacrylate) (PEMA) segments attached to a liquid crystal (LC) BB‐5(3‐Me) polyester having Mn = 29 kDa at both ends at PEMA volume fractions of φ%. The LC and PEMA blocks are segregated to form microlamellae; however, the lamellar length depends on the value of φ; B5‐29‐EMA‐22 forms long‐range lamellae, and B5‐29‐EMA‐44 comprises LC block lamellae separated by PEMA blocks. The stress response is similar between these copolymers in the elastic region but differs in the succeeding stage; B5‐29‐EMA‐22 films show a stress plateau, and B5‐29‐EMA‐44 films continuously increase the stress, displaying the strain hardening. Small‐angle X‐ray scattering measured simultaneously with the stress–elongation curves discloses that these different stress responses accompany individual lamellar deformations. B5‐29‐EMA‐22 undulates and folds the lamellae, whereas B5‐29‐EMA‐44 maintains parallel lamellar stacking, remarkably increasing the PEMA block lamellar thickness. These preferentially thickened lamellae are occupied by extended PEMA chains, which causes stress at the expense of the chain entropy, resulting in strain hardening. [ABSTRACT FROM AUTHOR]

[Display omitted] Sodium deoxycholate is a natural bile salt produced by animals and fulfilling important physiological processes. It is also used as dispersive surfactant and building block for self-assembled architectures in biology and material science. Although long debated, the study of its self-assembly in water is hereto incomplete and the models of the known aggregates are still controversial. This background suggests a complex scenario likely missing of additional mesophases. Electron and optical microscopy techniques were crossed with SAXS data for the research. Novel rod, sponge, vesicle, lamellae, nanotube phases and reversible transitions among them arise at conditions (concentration, pH, temperature, ionic strength, ionic composition) fitting the physiological working environment of sodium deoxycholate. These findings enlarge the perspective towards different directions. The integration of the previous literature with this work removes any interpretative contradiction since all the structures cover the entire spectrum of phases expected for surfactants, thus being explained according to the Israelachvili's scheme. It is not trivial that a single molecule can show such a high structural variability. This fact highlights a very versatile system. Probably it is not a coincidence that it occurs in a multitasking biomolecule. These results furnish fundamental knowledge to clarify the bile salts' role in vivo. [ABSTRACT FROM AUTHOR]

Abstract The detailed anatomy, ultrastructure and histology of the olfactory organ of Micropterus salmoides were investigated by a stereo microscope, a light microscope, and a scanning electron microscope. Its external structure shows a tube-like anterior nostril to stick out and a posterior nostril flat to the skin surface. Meanwhile, its internal structure, the olfactory chamber, contains a fan-shaped rosette structure with 9 to 11 lamellae in adult fish over 35 cm in standard length (SL) and two accessory nasal sacs (ethmoidal and lacrimal sacs) were found. Interestingly, the rosette in young fish under 15 cm in SL was a longitudinal structure in parallel with each of 4–5 lamellae. Histologically, the sensory epithelium (SE) on the olfactory chamber consists of 5 types of cells: olfactory receptor neurons, supporting cells, basal cells, lymphatic cells and mucous cells. In contrast, the non-sensory epithelium (NSE) has stratified epithelial cells, lymphatic cells and mucous cells. The mucous cells of the SE are abundant and distributed densely in one row on the outermost superficial surface, but the one of the NSE are less than the SE. From these results, the olfactory characters of M. salmoides may be related with its ecological habit spending in the middle layer of stagnant water contaminated, more or less.

The tubeworm Riftia pachyptila is a key primarily producer in hydrothermal vent communities due to the symbiosis with sulphur-oxidizing bacteria, which provide nourishment to the worm from sulphides, oxygen and carbon dioxide. These substances diffuse from the vent water into the bloodstream of the worm through their tentacular crowns, and then to the bacteria, hosted in a specialized organ of the worm, called a trophosome. The uptake rates of these substances depend on the surface/volume relationship of the tentacles. We here describe two morphotypes, 'fat' and 'slim', respectively, from the basalt sulphide-rich vents at 9 °N and 21 °N at the East Pacific Rise, and the highly sedimented, sulphide-poor vents at 27 °N in the Guaymas Basin. The 'fat' morphotype has a thicker body and tube, longer trunk and smaller tentacular crowns, whereas the 'slim' morphotype has shorter trunk, thinner body and tube, and presents longer tentacular crowns and has a higher number of tentacular lamellae. Given the dependence on sulphides for the growth of R. pachyptila , as well as high genetic connectivity of the worm's populations along the studied localities, we suggest that such morphological differences are adaptive and selected to keep the sulphide uptake near to the optimum values for the symbionts. 'Fat' and 'slim' morphotypes are also found in the vestimentiferan Ridgeia piscesae in similar sulphide-rich and poor environments in the northern Pacific. [ABSTRACT FROM AUTHOR]

The mechanisms of lath decomposition and dispersion were hitherto rarely explained due to limited understanding into the heterostructure deformation between two phases and associated interactions. In this work, the lath decomposition and dispersion were systematically investigated in a wide subtransus processing range of 0.001 s−1–1 s−1 and 745 °C–820 °C with the consideration into the heterostructure deformation and associated interactions. The relationship between flowing behavior and microstructure evolution were discussed. Results indicated that the initial buckling of α laths caused high peak strength. The rotation and twist of α laths are helpful to decrease the flow stress, but it caused serious extra deformation and dislocation storage in the β matrix. The lath decomposition dominated by the ablation was greatly contributed by the adiabatic temperature rise (ATR) near boundaries with high energies. The α laths could rotate under low strain rates, and numerous residual laths (RLs) could be obtained. The increment in strain rates to 0.1 s−1 resulted in earlier lath decomposition and softening, as well as to disperse α p particles and homogenize the β matrix. But an overhigh strain rate of ∼1 s−1 caused adiabatic shear bands. The low temperatures are unfavorable to the lath decomposition, while over-high temperatures diminished the extra deformation and ATR. On this basis, a deformation mechanism map for the subtransus processing of lamellae Ti-55531 alloy was established. This investigation sheds deeper insight into the tailoring of microstructure and prediction of flowing behavior for the subtransus processing of lamellae metastable-β Ti alloys. [ABSTRACT FROM AUTHOR]

Background contextDegenerative disc disease is a common pathologic disorder accompanied by both structural and biochemical changes. Changes in stress distribution across the disc can lead to annulus fibrosus (AF) damage that can affect the strength and integrity of the disc. Given that some present degeneration therapies incorporate biological regrowth of the nucleus pulposus (NP), it is crucial that the AF remains capable of containing this newly grown material.PurposeTo examine the resistance of AF to delamination using an adhesive peel test in experimentally degenerated rabbit discs.Study designExperimentally induced disc degeneration; excised AF tissue study.MethodsDisc degeneration was induced in eight New Zealand white rabbits by annular puncture; four additional rabbits served as controls. In experimental rabbits, an 18-gauge needle was inserted into the anterolateral AF region of levels L2-L3 and L4-L5, and disc height was monitored by X-ray. Animals were sacrificed at 4 and 12 weeks postsurgery and magnetic resonance images and X-rays were taken. Four discs were excised from the experimental animals; two punctured (L2-L3 and L4-L5) and two controls (L3-L4 and L6-L7). The same four discs were also excised from the age-matched control animals and served as nonpunctured control discs. To determine resistance to delamination, AF samples were dissected from each disc and subjected to a mechanical peel test at 0.5 mm/s.ResultsMagnetic resonance imaging and X-ray images confirmed dehydration of the NP and reduced disc height, similar to that found in clinical degeneration. Resistance to delamination was significantly lower in punctured/degenerated discs compared with both the nonpunctured discs from the same animal (27% lower) and the nonpunctured control discs (30% lower) (p=.024).ConclusionsThe findings of this study suggest that degeneration increases the potential for delamination between AF layers. Given this substantial change to the integrity of the AF after degeneration, clinical treatments should not only target rehydration or regrowth of the NP, but should also target repair and strengthening of the AF to confine the NP.

Properties of the Voronoi tessellations arising from random 2D distribution points are reported. We applied an iterative procedure to the Voronoi diagrams generated by a set of points randomly placed on the plane. The procedure implied dividing the edges of Voronoi cells into equal or random parts. The dividing points were then used to construct the following Voronoi diagram. Repeating this procedure led to a surprising effect of the positional ordering of Voronoi cells, reminiscent of the formation of lamellae and spherulites in linear semi-crystalline polymers and metallic glasses. Thus, we can conclude that by applying even a simple set of rules to a random set of seeds, we can introduce order into an initially disordered system. At the same time, the Shannon (Voronoi) entropy showed a tendency to attain values that are typical for completely random patterns; thus, the Shannon (Voronoi) entropy does not distinguish the short-range ordering. The Shannon entropy and the continuous measure of symmetry of the patterns demonstrated the distinct asymptotic behavior, while approaching the close saturation values with the increase in the number of iteration steps. The Shannon entropy grew with the number of iterations, whereas the continuous measure of symmetry of the same patterns demonstrated the opposite asymptotic behavior. The Shannon (Voronoi) entropy is not an unambiguous measure of order in the 2D patterns. The more symmetrical patterns may demonstrate the higher values of the Shannon entropy.

Comparing the ability of ST and WRB systems to describe soils with clay-enriched horizons was the aim of the present research. In arid and semi-arid regions of Iran, two study sites were considered. Three pedons at each study site were selected, described and sampled. Soils were classified based on ST (2014) and WRB (2015) systems. The micro-morphological investigations were done to confirm the illuvial clay accumulation in Bt horizons. Results showed that the required characteristics of an argillic horizon were not met in any of the Bt horizons. The poor correlation between ST and WRB systems was related to the different definition and criteria of clay-enriched horizons in the systems. Using “Differentic” and “Cutanic” qualifiers, the WRB system could describe properties of an argic horizon more efficiently than the ST system. Although the evidence of clay illuviation was observed as lamellae in some argillic horizons in the arid study site, the ST system could not display this characteristic. The WRB system indicates the presence of lamellae using a “Lamellic” qualifier in some cases. These issues are disadvantages for both classification systems in describing the soils with clay-enriched horizons. Defining Natrisalids great group and new subgroups including Calcic Natrisalids, Lamellic Argigypsids and Lamellic Calciargids seems necessary to improve deficiencies of both classification systems. Adding the “Lamellic” qualifier for Calcisols in the WRB system is highly suggested.

• Nucleation of the multilamellar tubes from the defects. • Membrane tubules grow in the absence of proteins, polymers or solute and leaflet asymmetry. • Kinetics of hydration control the dynamics of MLTs. • The tubular structures disintegrate into the bulk water phase inside the sealed sample cells. In this paper, experimental results on the swelling, dispersion and disintegration of the lamellae composed of the lipid, 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) in contact with excess water are described. Multilamellar structures nucleate and grow at the interface between the pure solvent and the lipid. The system evolves slowly via flow and coalescence of lamellae through a variety of non-equilibrium morphologies demonstrating that their dynamics is complex and non-universal, with no unique kinetic pathway. The tubular structures disintegrate slowly into the bulk water phase, inside the sealed sample chamber. [ABSTRACT FROM AUTHOR]

Summary: The desire to study macromolecular complexes within their cellular context requires the ability to produce thin samples suitable for cryo‐TEM (cryo‐transmission electron microscope) investigations. In this paper, we discuss two similar approaches, which were developed independently in Utrecht (the Netherlands) and Albany (USA). The methods are particularly suitable for both tissue samples and cell suspensions prepared by a high‐pressure freezer (HPF). The workflows are explained with particular attention to potential pitfalls, while underlying principles are highlighted ('why to do so'). Although both workflows function with a high success rate, full execution requires considerable experience and remains demanding. In addition, throughput is low. We hope to encourage other research groups worldwide to take on the challenge of improving the HPF– cryo‐FIB‐SEM – cryo‐TEM workflow. We discuss a number of suggestions to this end. Lay Description: Life is ultimately dictated by the interaction of molecules in our bodies. Highly complex equipment is being used and further developed to study these interactions. The present paper describes methods to prepare small, very thin lamellae (area of 5×5 µm2, thickness 50–300 nm) of a cell to be studied in a cryo‐transmission electron microscope (cryo‐TEM). Special care must be taken to preserve the natural state of molecules in their natural environment. In the case of cryo‐TEM, the samples must be frozen and kept frozen to be compatible with the vacuum conditions in the microscope. The frozen condition imposes technical challenges which are addressed. Two approaches to obtain the thin lamellae are described. Both make use of a focused ion beam (FIB) microscope. The FIB allows removal of material with nanometre precision by focusing a beam of ionised atoms (gallium ions) onto the sample. Careful control of the FIB allows cutting out of the required thin lamellae. In both strategies, the thin lamellae remain attached to the original sample, and the ensemble of sample with section and sample holder is transported from the FIB microscope to the TEM while being kept frozen. [ABSTRACT FROM AUTHOR]

Among various mechanisms responsible for the strength-ductility trade-off in metallic materials, the leading strategy is to delay the onset of necking by improving the work hardening rate via a number of metallurgical approaches such as heterogeneous or gradient microstructures. Recent research activities on high-entropy alloys also witness a wide range of alloy design capabilities that permit these microstructural designs such as the dual-phase lamellar microstructures. This work addresses the contrasting strength-ductility behavior of equiaxed and lamellar microstructures when geometric features are the only tuning parameter. It is found that failures in lamellae are preceded by necking in the hard phase, the growth of which is significantly confined and suppressed by the surrounding soft phase. Detailed finite element simulations reveal various degrees of strength-ductility trade-off and synergy, which mainly depend on the microscopic processes that govern the delayed neck growth and ductile fracture. The upper limit of tensile ductility is theoretically believed to be determined by short-wavelength necking in the hard phase.

Despite the prevalence of endocrinopathic laminitis, the pharmacologic options for preventing and treating the disease are severely limited. The present review aims to discuss the spectrum of potential therapeutic agents for the condition, ranging from early experimental compounds to agents nearing registration. There are different pharmacologic targets for, and approaches to, managing laminitis. Reducing hyperinsulinaemia is central to diminishing endocrinopathic laminitis risk, and a detailed understanding of the pathophysiology of insulin dysregulation is necessary to identify pathways that can be targeted to minimise post-prandial insulin secretion and action. This area of research is advancing rapidly, with several exciting prospects, such as sodium-dependent glucose co-transporter-2 inhibitors, on the horizon for the treatment of equine metabolic dysfunction. Drugs that directly target the lamellae and aim to reduce the damage inflicted on the lamellae as part of this condition, are not yet available. Although progress in this area of laminitis therapy is slower, improved understanding of the events that lead to lamellar failure has enabled the investigation of novel drugs that aim to prevent laminitis at the site of the lesion. Finally, a brief review is included of the directions being taken in the management of the chronic and acute pain that accompanies laminitis. Medications for relieving the pain associated with laminitis are currently the most-prescribed drugs for the disease, and range from simple, affordable and thoroughly tested options, such as phenylbutazone, to newer, less-understood applications such as paracetamol and gabapentin. In the future, endocrinopathic laminitis management plans will likely take a multi-faceted approach that still hinge on effective dietary management and exercise, but also include drugs that address foot pathology, pain and underlying endocrine disturbances. [ABSTRACT FROM AUTHOR]

One of the most important problem when adding recycle or waste materials to cement concrete is the poor adhesion between these materials and the cement matrix. For this reason, in this work, the effects of lamellae from beverage packaging (waste Tetra Pak), as well as of gamma rays on the mechanical properties of cement concrete were evaluated. The concrete specimens were produced with cement, water, gravel and sand; this last was partial substituted by lamellae of waste Tetra Pak (up to 30 wt. %) with sizes ranging 1.5 mm and 3.0 mm. Then, the concrete was irradiated with gamma rays at doses of 200 kGy and 300 kGy. The results show improvements up to 39 % and 30 % for compressive strength and the elasticity modulus, respectively, for concrete produced with 10 % of waste lamellae and irradiated at 300 kGy, respect to the values obtained for control concrete (without lamellae and non-irradiated). Such improvements are produced by both gamma rays and the lamella concentrations. Mechanical features were related with the lamellae before and after irradiation, based on the morphological and thermal changes (analyzed by SEM and TGA-DSC analyses, respectively), as well as with the chemical stability of their components (polyethylene and cellulose), analyzed by FT-IR spectroscopy.

The optimization of foam injection in porous media for enhanced oil recovery or soil remediation requires a large screening of surfactant formulations. Tests of foam stability in vials often used quick criteria to accelerate selection and ensure performance in porous media. Using a selection of surfactant formulations of different chemistry and foam behaviors, the correlation between foam in vials and in porous media is investigated. Along with foam stability, foamability which quantifies the ability to create foam is shown to play a role in the maximum apparent viscosity. This is a first evidence that foamability is a key parameter for the maximum apparent viscosity reached in a steady state of apparent viscosity. To account for the relative contribution of foamability and foam stability, a parameter is inspired from the widely accepted model of population balance. These results support a workflow based on large foam screening in a first step and sandpack experiments in a second step, prior to more representative but longer coreflood tests. Finally, these experimental data emphasize the relevance of population balance simulations as a description based on experimental measurement. Second, the flow visualization in the sandpack allows the extraction of a local velocity of the liquid in the flowing foam. This parameter gives an experimental evidence that the transition between the high-quality and low-quality regime corresponds to a change in the efficiency of foam lamellae network to transport gas concomitantly to liquid. The local liquid velocity also represents an indirect and easy measurement of flow structure, and it is shown to change from one formulation to another. This observation highlights the complex relation between local microstructure and physical chemistry of surfactants. [ABSTRACT FROM AUTHOR]

The detailed anatomy, ultrastructure and histology of the olfactory organ of Micropterus salmoides were investigated by a stereo microscope, a light microscope, and a scanning electron microscope. Its external structure shows a tube-like anterior nostril to stick out and a posterior nostril flat to the skin surface. Meanwhile, its internal structure, the olfactory chamber, contains a fan-shaped rosette structure with 9 to 11 lamellae in adult fish over 35 cm in standard length (SL) and two accessory nasal sacs (ethmoidal and lacrimal sacs) were found. Interestingly, the rosette in young fish under 15 cm in SL was a longitudinal structure in parallel with each of 4–5 lamellae. Histologically, the sensory epithelium (SE) on the olfactory chamber consists of 5 types of cells: olfactory receptor neurons, supporting cells, basal cells, lymphatic cells and mucous cells. In contrast, the non-sensory epithelium (NSE) has stratified epithelial cells, lymphatic cells and mucous cells. The mucous cells of the SE are abundant and distributed densely in one row on the outermost superficial surface, but the one of the NSE are less than the SE. From these results, the olfactory characters of M. salmoides may be related with its ecological habit spending in the middle layer of stagnant water contaminated, more or less. [ABSTRACT FROM AUTHOR]

The main function of the intervertebral disc is biomechanical function, since it must resist repetitive high loadings, while giving the spine its flexibility and protecting the spinal cord from over-straining. It partially owes its mechanical characteristics to the lamellar architecture of its outer layer, the annulus fibrosus. Today, no non-invasive means exist to characterize annulus lamellar structure in vivo. The aim of this work was to test the feasibility of imaging annulus fibrosus microstructure in vivo with ultrasonography. Twenty-nine healthy adolescents were included. Ultrasonographies of L3–L4 disc were acquired with a frontal approach. Annulus fibrosus was segmented in the images to measure the thickness of the lamellae. To validate lamellar appearance in ultrasonographies, multimodality images of two cow tail discs were compared: ultrasonography, magnetic resonance and optical microscopy. In vivo average lamellar thickness was 229.7 ± 91.5 μm, and it correlated with patient body mass index and age. Lamellar appearance in the three imaging modalities in vitro was consistent. Lamellar measurement uncertainty was 7%, with good agreement between two operators. Feasibility of ultrasonography for the analysis of lumbar annulus fibrosus structure was confirmed. Further work should aim at validating measurement reliability, and to assess the relevance of the method to characterize annulus alterations, for instance in disc degeneration or scoliosis. [ABSTRACT FROM AUTHOR]