Multilayered Zone Research Articles

Identification of biological components for sialolith formation organized in circular multi-layers

According to the previous studies of sialolithiasis reported so far, this study is aimed to identify the biological components of sialolith, which show different ultrastructures and chemical compositions from other stones, cholelith and urolith. Twenty-two specimens obtained from 20 patients were examined histologically, and analyzed with micro-CT, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and transmission electron microscopy (TEM). All sialoliths (n = 22) observed in this study showed a central nidus, which was filled with organoid matrix admixed with exosome vesicles, loose calcium apatite crystals, and many bacteria. The micro-CT and SEM observation clearly defined a single or multiple central nidus(es) encircled by highly calcified compact zone. The circular compact zone showed a band-like calcification, about 1–3 mm in thickness, and usually located between the central nidus and the peripheral multilayer zone. But some sialoliths (n = 5) showed severe erosion of compact zone by expanding multilayered zone depending on the level of calcification and inflammation in sialolith. By observing TEM images, many exosome vesicles and degraded cytoplasmic organelles were found in the central nidus, and some epithelial cells were also found in the calcified matrix of peripheral multilayer zone. Particularly, EDS analysis indicated the highest Ca/P ratio in the intermediate compact zone (1.77), and followed by the central nidus area (1.39) and the peripheral multilayer zone (0.87). Taken together, these data suggest that the central nidus containing many inflammatory exosomes and degraded cytoplasmic organelles has a potential to induce a band-like calcification of compact zone, and followed by the additional multilayer deposition of exfoliated salivary epithelial cells as well as salivary materials. Thereby, the calcium apatite-based sialolith is gradually growing in its volume size, and eventually obstructs the salivary flow and provides a site for the bacterial infection.

Topographic and anatomical features of muscular and vascular structures in lateral cervical region during prenatal period of human ontogenesis

Background. One of topical areas of morphological research is features of topographic a relationships of the vascular, nervous, muscular, fascial and cartilaginous structures of the neck in prenatal period of human ontogenesis, as data on their formation at different stages of development will improve diagnostic methods of visualization and surgical correction of congenital and acquired pathologies of head and neck. Objective. To find out the peculiarities of synthopia of vascular and muscular structures of the lateral cervical region in human prefetuses. Methods. 9 human prenatal specimens aged 9-12 weeks of prenatal development have been studied by using a set of morphological methods, according to existing bioethical norms. Results. During 9th week of development, bony and musclar boundaries of the lateral triangle of the neck, the carotid vagina, and the components of the vascular-nervous bundle of the neck have been determined. Within the carotid triangle, the external carotid artery is located superficially; it is crossed frontally by the cervical branch of facial nerve and the sublingual nerve. The superior thyroid artery departs from the external carotid artery at the level of the cartilaginous model of the large horns of hyoid bone and passes to the rudiment of thyroid gland. Retropharyngeal space is found at 9th week of development, moderately filled with adipose tissue. The anterior vertebral plate of the cervical fascia forms the bottom for posterior triangle of neck. Conclusion. The lateral cervical region in human prefetuses is represented by a multilayered topographic zone with formed boundaries and contents. Cervical fascia forms carotid vagina within the carotid triangle, and pharyngeal space. The course of blood vessels and nerves within the lateral cervical region is variable. Three-dimensional reconstructions of prefetuses serve as evidence of the early formation of definitive topographic connections within early bony and cartilaginous models in relation to the muscles of the anterior and lateral cervical regions.

Elucidation of orientation relations between Fe-Cr alloys and corrosion products after high temperature SO2 corrosion

The early stages of corrosion of Fe-Cr-model alloys (2 and 9 % Cr) were investigated after exposure at 650 °C in 0.5 % SO2 containing gas by electron backscattered diffraction (EBSD) and transmission electron microscopy (TEM). The impact of the grain orientation of the base alloy on the orientation relations of the corrosion products is presented. After 2 min – 5 min exposure the formation of a multi-layered corrosion zone was discovered. A clear orientation relationship between ferrite and the (Fe,Cr)3O4 spinel could be demonstrated. The obtained results show the importance of the grain orientation on oxidation resistance.

Isotopic and geochemical interpretation of groundwater under the influences of anthropogenic activities

Groundwater resources are increasingly exploited for industrial and agricultural purposes in many arid/semi-arid regions globally. In order to gain a harmonious development among groundwater resources and economic benefits, urgent investigation of the impacts of anthropogenic activities on the groundwater chemistry is required. Understanding hydrochemical mechanism of groundwater in Yinchuan Plain, arid and semi-arid area in Northwestern China, plays a significant role in water resources planning in this ecologically sensitive area. In this paper, a total of 460 phreatic water samples were collected, including 58 water samples containing isotopic data (D and 2H). Results demonstrate that water chemistry type and isotopic data of phreatic water presents a zonation characteristic from west to east and from south to north. In the eastern part of the Helan Mountain (A1 zone), the type of hydrochemistry is mainly HCO3·SO4-Ca·Mg, SO4·HCO3-Ca·Mg, which is mainly recharged by the bedrock fissure water of Helan Mountain. However, in the southern Qingtongxia (A2 zone) are HCO3-Na HCO3-Ca·Mg, which receives irrigation and spring water recharge. Phreatic aquifer in Multi-layered structure zone (A3 zone) reflect multiple recharge sources to the aquifer, the water chemistry demonstrates diverse variations. The anion was dominated by the HCO3, while the cation is dominated by sodium. The predominant controlling factors of phreatic water hydrochemistry are divided into anthropogenic activities and natural conditions. Natural conditions mainly include the existence form and lithology of the aquifer, sources of groundwater recharge, soil salinity, and evaporation, mineral dissolution, ion exchange and adsorption and mixing effect. Meanwhile, among natural factors, minerals dissolution in groundwater is the main process dominating the hydrochemical evolution of the groundwater. The other is anthropogenic activities which can be classified as groundwater pollution, excessive exploitation or excretion of groundwater, and excessive groundwater recharge.

Artificial recharge efficiency assessment by soil water balance and modelling approaches in a multi-layered vadose zone in a dry region

ABSTRACTTo assess recharge through floodwater spreading, three wells, approx. 30 m deep, were dug in a 35-year-old basin in southern Iran. Hydraulic parameters of the layers were measured. One well was equipped with pre-calibrated time domain reflectometry (TDR) sensors. The soil moisture was measured continuously before and after events. Rainfall, ponding depth and the duration of the flooding events were also measured. Recharge was assessed by the soil water balance method, and by calibrated (inverse solution) HYDRUS-1D. The results show that the 15 wetting front was interrupted at a layer with fine soil accumulation over a coarse layer at the depth of approx. 4 m. This seemed to occur due to fingering flow. Estimation of recharge by the soil water balance and modelling approaches showed a downward water flux of 55 and 57% of impounded floodwater, respectively.

Assessing dorsal scute microchemistry for reconstruction of shortnose sturgeon life histories

The imperiled status of sturgeons worldwide places priority on the identification and protection of critical habitats. We assessed the micro-structural and micro-chemical scope for a novel calcified structure, dorsal scutes, to be used for reconstruction of past habitat use and group separation in shortnose sturgeon (Acipenser brevirostrum). Dorsal scutes contained a dual-layered structure composed of a thin multi-layered translucent zone lying dorsally above a thicker multi-layered zone. Banding in the thick multi-layered zone correlated strongly with pectoral fin spine annuli supporting the presence of chronological structuring that could contain a chemical record of past environmental exposure. Trace element profiles (Sr:Ca), collected using both wavelength dispersive electron microprobe analysis and laser ablation inductively coupled mass spectrometry, suggest scutes record elemental information useful for tracing transitions between freshwater and marine environments. Moreover, mirror-image like Sr:Ca profiles were observed across the dual-zone structuring of the scute that may indicate duplication of the microchemical profile in a single structure. Additional element:calcium ratios measured in natal regions of dorsal scutes (Ba:Ca, Mg:Ca) suggest the potential for further refinement of techniques for identification of river systems of natal origin. In combination, our results provide proof of concept that dorsal scutes possess the necessary properties to be used as structures for reconstructions of past habitat use in sturgeons. Importantly, scutes may be collected non-lethally and with less injury than current structures, like otoliths and fin spines, affording an opportunity for broader application of microchemical techniques.

Formation kinetics of multi-layered interfacial zone between γ-TiAl and glass–ceramic coatings via interfacial reactions at 1000 °C

Glass–ceramic coatings are investigated for high temperature protection of γ-TiAl. This investigation focuses on the interfacial reactions between γ-TiAl and a glass–ceramic coating at 1000°C in air by means of transmission/scanning electron microscopy, energy dispersive spectroscopy and X-ray diffraction. A thin interfacial zone of multilayered glass/Ti5Si3/α-Al2O3/Ti3Al at the interface was observed after oxidation for several hours. Both the growth of Ti5Si3 and α-Al2O3 layers obeyed parabolic rules, while the thickness of the Ti3Al layer increased first and then decreased. The mechanism for formation kinetics of the interfacial zone was discussed.

The Impact of Diffusion Process on the Interface Microstructure in AZ91 Magnesium Matrix Composites Reinforced with TiN Nanolayer Modified Carbon Fibres

A TiN nanocoating was deposited on carbon fibres before their consolidation with AZ91E magnesium alloy, provided as a matrix of the composite. The main interest was the interface microstructure. Structural investigations were performed with a FE-SEM Hitachi 3200S scanning electron microscope and a Tecnai G2 FEG high resolution electron microscope equipped with energy dispersive X-ray spectrometer (EDS) and high angle annular dark field (HAADF) detectors. The observations of the fibre-matrix interface revealed the presence of a multilayered zone around the fibres. It consisted of a regular oxide layer with a thickness of approx. 100 nm around the fibre, followed by a titanium-rich layer and a region of longitudinal sharp shaped crystals directed toward the magnesium alloy matrix. This type of interface microstructure suggests that deposition of TiN as a technological nanolayer ensures the proper wettability of fibres by the metal matrix, but does not prevent diffusion processes. It was revealed that both, i.e. diffusion of elements contained in the matrix through the TiN nanolayer and diffusion of oxygen and carbon toward the surface took place.

High efficient optical focusing of a zone plate composed of metal/dielectric multilayer

We numerically investigate the optical field enhancement by a metal/dielectric multilayered zone plate. The optical field enhancement at the focal point of a zone plate originates not only from surface plasmon polaritons (SPPs)-assisted diffraction process along the propagation direction of incident light, but also from multiple scattering and coupling of surface plasmons (SPs) along the metal/dielectric multilayer films. By comparing multilayered zone plates to a conventional monolayered zone plate, we present the effects associated with the number of building blocks and different dielectric materials in the building block on the efficiency of the transmission.

Numerical Solution of Ocular Fluid Dynamics in a Rabbit Eye: Parametric Effects

Numerical calculations of the aqueous humor dynamics in the anterior chamber of a rabbit's eye are presented to delineate the basic flow mechanisms. The calculations are based on a geometrical model of the eye, which represents the Trabecular meshwork (TM) as a multilayered porous zone of specified pore sizes and void fraction. The outer surface of the cornea is assumed to be at a fixed temperature (corresponding to the ambient temperature), while the iris surface is assumed to be at the core body temperature. Results are obtained for both the horizontal upward-facing orientation of the eye, and the vertical orientation of the eye. Parameters varied include: the temperature difference between the iris and the cornea to underscore the important role of buoyancy in driving the aqueous humor flow; and, the pupil size reflecting different levels of ambient light. Buoyancy is observed to be the dominant driving mechanism for the convective motion in both orientations of the eye. Variations in the pupil size appear to have little influence on the IOP or flow distribution in view of the dominant role of buoyancy in controlling the flow motion. The study provides distributions of the shear stress and flow patterns and delineates the important role of the eye-orientation on these results.

Form follows function: developmental and physiological view on ventricular myocardial architecture

The arrangement of myocytes within the ventricle is critical for its contractile performance, as evidenced by significant functional impairment seen in cardiomyopathies associated with myofiber disarray or post-infarction remodeling. A review on this topic by Anderson and associates provides anatomical insight gained from a multitude of approaches, and concludes that the best concept is that of syncytial continuum with supporting collagenous matrix. The overall arrangement is in the form of several intertwined helices, and the authors find no support for a recently suggested ventricular myocardial band hypothesis. This commentary aims at providing a developmental and physiological perspective on this purely anatomical concept. Unlike some other organ systems, the developing heart has to function since very early stages to support the oxygen and nutrition demands of the growing embryo, thus putting some constraints on heart development. The ventricular myocardial architecture transforms from a single-layered tube through trabeculated stages into a mature form that relies on a multi-layered compact zone. The first evidence of helical patterns is found in trabeculated hearts during ventricular contraction, and layers with different helix pitch develop during later fetal stages as the compact zone thickens. The second major point determining ventricular contraction is the sequence of its electrical activation. The ventricular activation sequence changes concomitantly with its morphology, from slow peristaltoid through base-to-apex pattern found in looped trabeculated hearts, to mature apex-to-base direction. Thus, adult ventricular myocardial architecture is best understood when one also considers the way it developed together with its electrical activation sequence and contraction pattern.

Rapid and large-scale formation of chondrocyte aggregates by rotational culture.

Chondrocytes in articular cartilage synthesize collagen type II and large sulfated proteoglycans, whereas the same cells cultured in monolayer (2D) dedifferentiate into fibroblastic cells and express collagen type I and small proteoglycans. On the other hand, a pellet culture system was developed as a method for preventing the phenotypic modulation of chondrocytes and promoting the redifferentiation of dedifferentiated ones. Because the pellet culture system forms only one cell aggregate each tube by a centrifugator, the pellet could not be applied to produce a tissue-engineered cartilage. Therefore, we tried to form chondrocyte aggregates by a rotational culture, expecting to form a large number of aggregates at once. In order to increase cell-cell interactions and decrease chondrocyte-material interaction, dishes with low retention of protein adsorption and cell adhesiveness were used. In addition, rotational shaking of the dish including cells was attempted to increase the cell-cell interaction. The shaking speed was set at 80 rpm, so the cells would be distributed in the center of the dish to augment the frequency of cell-cell contact. Under these conditions, bovine articular chondrocytes started aggregating in a few hours. At 24-36 h of rotational culture, aggregates with smooth surfaces were observed. Parameters such as increase of culture time and addition of TGF-beta controlled diameters of the aggregates. There were many fusiform cells at the periphery of the aggregates, where the cells tended to form a multilayered zone in cross sections. In addition, lacune-like structure, which was almost the same as pellet culture, was observed. It was found that the internal structure of the aggregates was similar to that of pellets reported previously. Therefore, the aggregates formed by a rotational culture could become an essential component to make tissue-engineered artificial cartilage.

Macroscopic equations for vapor transport in a multi-layered unsaturated zone

Using the method of homogenization, we present a systematic derivation of the macroscopic equations for air flow and chemical vapor transport in an unsaturated zone with a periodic structure of heterogeneity. The effective specific discharge and hydrodynamic dispersion coefficient are expressible in terms of some cell functions, whose analytical solutions are sought for the simple case of alternate stacking of two strictly plane layers of different properties. For this kind of bi-layered composite, the effects of convection velocity and layer property contrasts on the longitudinal and transverse components of the hydrodynamic dispersion coefficient are investigated.

The main features of the interface between the crust and the upper mantle in the Middle Urals (in the vicinity of the deep drillhole SG-4)

Analysis of both P- and S-wave seismic data from the Middle Urals supports the existence of a multi-layered crust-mantle transition zone and a deep crustal root along the central axis of the Urals. Data from deep seismic sounding (DSS) nuclear explosions (Rubin I and Quartz), quarry blasts from industrial sources, and wide-angle experiments (Krasnouralsky and UWARS) are integrated to form the basis for this study. The crust-mantle transitional complex begins in the eastern part of the Pre-Uralian foredeep where it consists of relatively thin layers (thickness ∼ 3–5 km) with alternating high- and low-velocity layers. Toward the axis of the Urals the transition zone thickens to 10–15 km beneath the Tagil arc before thinning toward the East Uralian zone. The average interval P wave velocity for the transition zone varies from 7.3–7.8 km/s. The thickness of the crust is found to reach a maximum of 55–60 km in the vicinity of the super deep borehole SG4. In the area of SG-4, the Moho shallows from the Tagil zone west to the Central Urals uplift and Western Urals fold zone. The upper mantle is characterized by a nearly uniform velocity of 8.5 km/s.

ZO-1 Reorganization and Myofibroblast Transformation of Corneal Endothelial Cells after Freeze Injury in the Cat

Corneal endothelial wound healing following scrape injury in the rabbit and cat is characterized by cell spreading and maintenance of a normal endothelial phenotype consisting of apically-localized, circumferential microfilament bands and cell border-associated ZO-1, a tight junction protein and marker for endothelial differentiation. In contrast, after freeze injury in the rat and rabbit endothelial cells develop basally organized microfilament bundles (stress fibers), and appear to proliferate and form a multilayered zone at the wound margin. The purpose of the present study was to determine if similar phenotypic changes are observed after freeze injury in the cat corneal endothelium, which like human, normally has limited growth potential. In addition, changes in ZO-1 and α-smooth muscle actin (a marker for myofibroblast transformation) distribution were evaluated for the first time following freeze injury.In vivoendothelial healing of standard 3 mm diameter freeze injury was evaluated at 4 hr, 12 hr, 24 hr, 48 hr, 3 days and 5 days after injury in 22 cat eyes. Corneas were stained with phalloidin, propidium iodide, and anti-ZO-1, anti-α-smooth muscle-specific actin or anti-fibronectin antibodies. Protein organization was then evaluated using immunofluorescence and laser scanning confocal microscopy. Beginning at 12 hr after injury, endothelial cells appeared to extend and elongate over the wound area. By 48 hr after injury, migrating endothelial cells formed a multilayered activated zone (AZ) at the wound margin. Endothelial cells immediately adjacent to the AZ maintained a normal circumferential organization of f-actin colocalized with cell border-associated anti-ZO-1 staining at all time points observed. However, within the AZ there was an abrupt increase in phalloidin staining and development of prominent microfilament bundles (stress fibers), as well as a loss of normal anti-ZO-1 staining. The AZ also stained positively for anti-α-smooth muscle actin and anti-fibronectin antibodies. Changes in the distribution of ZO-1 were observed as early as 4 hr after injury, and appeared to precede f-actin reorganization. These data indicate that endothelial healing after freeze injury in the cat involves a loss of normal endothelial differentiation and cell connectivity, and transformation to a myofibroblastic phenotype.

A high-efficiency quarter-wave zone plate reflector

A multilayered quarter-wave zone plate reflector antenna operating in the microwave range is presented. The theory for designing the reflector and experimental results are given. An efficiency of 55% was obtained with a prototype reflector antenna. >

Pericarp anatomy and evolution inCoriaria (Coriariaceae)

The first overall study of pericarp anatomy ofCoriaria is presented to discuss its evolution and relationships within a genus. All 14 species investigated (including 11 narrowly defined species) have somewhat bilaterally flattened mature fruits with five to seven (or more) longitudinal costae. They share a usually nine-(or more-)cell-layered (at intercostal region), stratified mature pericarp, which is basically constructed by an exocarp, an outer, a middle and an inner zone of mesocarp, and an endocarp. While a multi-layered endocarp is composed of circumferentially elongate fibres, a multi-layered inner zone of the mesocarp comprises longitudinally elongate fibres. Despite its uncertain systematic value, the presence of those fibres arranged crisscross is a characteristic feature of the genus. Comparisons among species indicate thatCoriaria terminalis, a species of the Eastern Hemisphere, retains a basic or archaic, well-stratified pericarp structure similar to the one found in all the species investigated of the Southern and Western Hemisphere, and that four species of Asia,Coriaria napalensis, C. sinica, C. intermedia andC. japonica, share a specialized structure (lacking the outer zone of the mesocarp) indicative of their mutual close affinity. Comparisons further suggest distinctness ofCoriaria intermedia, as well as variously derived position ofC. myrtifolia andC. japonica.

Ultrastructure of gonadotropin-releasing hormone neuronal structures derived from normal fetal preoptic area and transplanted into hypogonadal mutant (hpg) mice

The hpg mutant mouse lacks the neurohormone gonadotropin-releasing hormone (GnRH) and hence has a reproductive deficit. This deficit can be corrected by placement of normal fetal preoptic area into the third ventricle (see Krieger et al., 1985). We have now used ultrastructural immunocytochemistry to investigate the morphology of GnRH neurons in such intraventricular grafts, the routes that their axons take as they exit into the host, and the neurosecretory terminations that they make in the host median eminence. The GnRH cells in the transplant were similar in morphology to that reported for such cells in the preoptic area of other rodents. There was a large central nucleus, frequently indented and containing 1 or 2 nucleoli. The thin rim of cytoplasm was filled with rough endoplasmic reticulum, Golgi stacks, and mitochondria. Both dendritic and axonal profiles were identified, and a modest synaptic input to the former was found. Between the host and the implant a complex multilayered ependymal zone developed, and it was through this region that GnRH axons exited into the host arcuate nucleus and median eminence, usually surrounded by ependymal or glial elements. Within the median eminence, GnRH terminals were in close association with fenestrated blood vessels forming a normal neurosecretory terminus.

The pericarpic structure ofWithania somnifera (L.) Dunal

The small berry ofWithania somnifera is enclosed in an inflated calyx. Its pericarp is histologically differentiated into a 5–6 layered compressed collenchymatous epicarp, a multilayered zone of parenchymatous mesocarp and a 3–4 layer thick endocarp. The anomocytic stomata surrounded by 4–6 epidermal cells occur only in the basal region of the fruit. The number of cells of the mesocarp does not increase much, but its cells become enlarged, vacuolated and separated at maturity. The endocarpic lobes adhere to the placental false septa and enclose the individual seeds in separate chambers.

Development and structure of seeds and fruits in Compositae, tribe Inuleae

Developmental anatomy of seeds and fruits inHelichrysum bracteatum andVicoa indica has been investigated. InH. bracteatum the mature seed coat is usually composed of 2 cell layers but inV. indica it is represented by crushed remains of the integumentary cells. Only the outermost layer of the endosperm persists in the mature seeds. The pericarp inH. bracteatum is made up of a layer of epidermis followed by a multilayered sclerenchymatous zone while inV. indica the pericarp shows an epidermis and a few subjacent layers which remain thin-walled and at places include fibrovascular bundles.