The microstructure of buccal cavity and alimentary canal of Siganus rivulatus: Scanning electron microscope study

The microstructure of the oral cavity and alimentary canal of herbivorous fish Siganus rivulatus collected from the Red Sea were investigated by using scanning electron microscope (SEM). The results showed that S. rivulatus has three types of teeth, tri‐cusped, bi‐cusped, and papilliform. A taste bud (Type I) was recorded in the oropharyngeal cavity. Characteristic styles of microridges on the cell's surface inside the buccal cavity were recorded. Also, the distribution of the mucous cells in the lining of the mouth cavity, alimentary canal was observed. Mucosal folds along the distinct parts of alimentary canal, showed characteristic pattern which was complex in the intestinal mucosa. The results concluded that there are characteristic microstructures according to feeding habitat compared with other bony fishes.     

Morphological characterization of the oral cavity of the gilthead seabream (Sparus aurata) with emphasis on the teeth‐age adaptation

Gilthead sea bream with different age groups that collected from Seawater fisheries, Ismailia Governorate, Egypt, were examined by gross anatomy and scanning electron microscopy to assess the morphological characteristics of the oral cavity. Teeth patterns showed that the gilthead sea bream is adapted to the feeding pattern according to age development, as it modified from spiny form teeth in young fishes to obelisk‐like teeth and flat dome‐like teeth in growing fishes, with differentiation of teeth into three pairs of canine and conical teeth, that later differentiated to small and large flat teeth. With development, the apical pouch also showed morphological differentiation from curve‐like in small fishes to Y‐letter shape in medium‐sized fishes, which later grow to completely covering the lower jaw in grown adult fishes. Tongue papillae, on the other hand, showed some differentiation being smoother in growing fishes than adult ones. Consistent with development differentiation, the palatine region of young fishes appeared separated from the palate by deep palatine fissure, while that the same palatine region was continuous with the palate with a remnant of palatine fissure as shallow groove was noticed in grown big fishes. Taste buds were characterized in the oral cavity of small and large fishes however in large fishes; the taste buds were more prominent especially at the palate and palatine folds. These and other morphological features of the oral cavity and the feeding habits in small and large gilthead sea bream fishes were recorded. Microsc. Res. Tech. 79:227–236, 2016. © 2016 Wiley Periodicals, Inc.     

Histomicroscopy and normal anatomy of the adult killifish Aphanius hormuzensis (Teleostei; Aphaniidae) from the Persian Gulf coastal environment

The histomicroscopy and normal anatomy of the major body organ systems were investigated in the adult killifish, Aphanius hormuzensis using histological examination, X‐ray imaging, double staining, light microscopy and scanning electron microscopy (SEM). Based on the histomicroscopic observations, the kidney, liver and swim bladder in the studied species were comparable to other fish models. The anterior portion of the kidney is bulbous, while the posterior portion is narrow and elongated; the liver has a single lobe and the swim bladder is a single‐chambered organ with no connection to the digestive tract (physoclistous). X‐ray imaging and double staining examination showed 12 abdominal and 15 caudal vertebrae and a single hypural plate in the caudal skeleton. According to light microscopy, the scales were rounded to pentagonal in shape with three types of radii (primary, secondary and tertiary), and the urohyal bone was elongated. SEM microscopy showed a single row of tricuspid teeth on the upper and lower jaw, respectively, each tooth has two lateral cusps that are shorter than the middle one. The number of teeth was 17–18 in the upper jaw and 19–20 in the lower jaw. The saccular otoliths were rounded‐trapezoid in shape with a moderately incised and V‐shaped excisura. The members of killifishes are an important group for biologists because of their evolutionary properties, regeneration capacity and usefulness as biological control and also for the ecotoxicological assessment of environmental pollution. The outcomes of this study may provide a useful basis for future research on the genus Aphanius.     

Distribution of ghrelin peptide in the gastrointestinal tract of stomachless and stomach-containing teleosts

The occurrence and localization of ghrelin peptide in the gastrointestinal tract of Carassius auratus and Dicentrarchus labrax, two fish species that exhibit different feeding behavior, different habitats, and different anatomical organizations of the gastroenteric tract, were examined by immunohistochemical methods and western blotting analysis. All of the gastrointestinal segments studied displayed immunohistochemical localizations of ghrelin peptide. Numerous single or clustered immunoreactive cells were found along the gastric folds, particularly in the pyloric region of Dicentrarcus labrax, whereas scattered ghrelin immunoreactive cells were observed in the intestinal epithelium of both fish species. Double immunolabeling PGP 9.5/ghrelin demonstrated the localization of ghrelin peptide also in nerve fibers and neuronal cells of the submucosal and myenteric plexuses, often in association with vascular structures. Western blotting analysis confirmed the presence of ghrelin peptide in the gatrointestinal tract of both species studied, whose molecular weight was similar to that of the corresponding mammalian prepro-ghrelin. The findings could support the hypothesis that this peptide is an important appetite regulator in fish and could confirm the presence of the ghrelin peptide, starting from its precursor proteins, in the gastrointestinal tract of the goldfish and the sea bass. Microsc. Res. Tech. 2009. © 2009 Wiley-Liss, Inc.     

Surface ultrastructure of gills in relation to the feeding ecology of an angler catfish Chaca chaca (Siluriformes,Chacidae)

Surface ultrastructure of the gills of the angler catfish Chaca chaca was investigated to unravel the adaptive modifications associated with the feeding ecology of the fish. The fish is often found in mud or in soft substrates where they remain buried both for protection and to feed. Gill rakers present on the gill arch in most fish species are absent in this fish. The absence of gill rakers are associated with the feeding habit of the fish and is considered to facilitate the swallowing of captured prey smoothly without any hindrance. Highly corrugated surface of the gill arch and gill filaments could be associated to retain water/mucus to prevent dessicassion of the fish. Papillae like epithelial protuberances each bearing a taste bud at its summit toward the pharyngeal side of the gill arch is associated with the sorting of the food. Large number of mucous goblet cells on the gill arch epithelium are considered to secret copious mucus to lubricate the prey for easy swallowing. In C. chaca the gill septa between gill filaments are reduced. This could enhance the flexibility and permit the free movement of the gill filaments. Extensive secondary lamellae and infrequent mucous goblet cells on secondary lamellae are associated to increase the surface area to enhance efficiency of gaseous exchange.     

Rotor dynamic instability analysis on hybrid air journal bearings

Hybrid air journal bearings with multi-array of 1, 2, 3, 4, or 5-row orifice feedings are analyzed for the problem of rotor dynamic instability. The bearing stiffness and damping coefficients are calculated numerically to determine threshold rotor mass under various operating conditions. The hybrid porous air journal bearings are also analyzed for comparison to investigate the similarities in dynamic characteristics between the multi-array of orifice feeding bearings and the porous bearings. The results show that the porous bearing is more stable than the orifice feeding bearing at lower rotation speeds (Λ<0.1) or at higher rotation speeds (Λ>1) with lower feeding parameters (λ_P<10⁻⁸). The 5-row orifice feeding bearing is more stable than the porous bearing at moderate speeds (0.3<Λ<0.6) with lower feeding parameters (λ₀<10⁻⁴).     

The application of cryo-SEM techniques to the study of the symbiotic association in the Azolla leaf cavity

The preparation of frozen-hydrated samples for scanning electron microscopy to observe symbionts in Azolla is described and compared to the conventional method of chemical fixation followed by critical-point drying. The frozen-hydrated specimens preserve the structure of the associating symbionts and the liquid phase in the Azollaleaf cavity. The leaf cavity structure and the endosymbionts in the frozen-hydrated specimens were intact and unharmed throughout the fixation. The cyanobiont cells were distributed along the envelope of the leaf cavity, and did not aggregate around the hair cells, as reported for chemical fixation specimens. The mucilage layer removed by the chemical fixation could be observed in the cryo-fixation specimens, especially at the lower part of the cavity.     

Design of domestic electric oven using uniformity of browning index of bread in baking process

The browning index (BI) represents the color of browning bread and is an important part of the baking process when using a domestic electric oven. Previous studies have developed CFD models for analyzing the baking process, but there are deficiencies in finite element analysis for evaluating the browning of bread. In this study, the uniformity of browning index (UBI) was defined, and a finite element analysis method to reduce the cost and time required for the evaluation of UBI by experiment was suggested for the baking process to develop a new electric oven. The errors of the temperature in the oven cavity and the UBI between experiments and the analysis decreased when using an on/off algorithm for the heater. The CFD results show that the temperature distribution and air flow in the oven cavity are dominant factors in the UBI. The length of the fan cover outlet was designed to reach the performance objective of the UBI less than 12.5 and to control the air flow in the cavity. Baking experiments with the proposed model were performed for verification.

     

Accessing osteocyte lacunar geometrical properties in human jaw bone on the submicron length scale using synchrotron radiation μCT

The architectural properties of the osteocyte cell network provide a valuable basis for understanding the mechanisms of bone remodelling, mineral homeostasis, ageing and pathologies. Recent advances in synchrotron microtomography enable unprecedented three‐dimensional imaging of both the bone lacunar network and the extracellular matrix. Here, we investigate the three‐dimensional morphological properties of osteocyte lacunae in human healthy and bisphosphonate‐related osteonecrotic jaw bone based on synchrotron X‐ray computed tomography images, with a spatial isotropic voxel size of 300 nm. Bisphosphonate‐related osteonecrosis of the jaw is a relatively new disease with increasing incidence, which remains poorly understood. A step forward in elucidating this malady is to assess whether, and how, the morphology of the osteocyte lacunar network is modified in the affected jaw tissue. We evaluate thousands of cell lacunae from five specimens of which three originate from patients diagnosed with bisphosphonate‐associated osteonecrosis. In this exploratory study, we report three‐dimensional quantitative results on lacunar volumes (296–502 μm³), shape (approximated by an ellipsoidal shape with principal axes a > b > c, such that a = 2.2b and a = 4c) and spatial distribution (i.e., 50% of the mineralized matrix volume is located within 12 μm to the closest lacunar boundary) at submicron resolution on such specimens. We observe that the average lacunar volumes of the bisphosphonate‐related osteonecrotic jaw specimens were within the range of volumes found in the two specimens originating from healthy donors and conclude that lacunar volumes are not the key element in the course of bisphosphonate‐related osteonecrotic jaw. In three out of five specimens we observe lacunar volume sizes in segmented osteons to be significantly different compared to lacunar volumes in the adjacent tissue regions. Furthermore, we quantify the number of lacunae containing small dense objects (on average 9%). In contrast to lacunar morphology we report the lacunar density (16 000–50 000 per mm³) to be different in jaw bone tissue compared to what has been reported in femoral sites.     

Creep characterization of type 316LN and HT-9 stainless steels by the K-R creep damage model

The Kachanov and Rabotnov (K-R) creep damage model was interpreted and applied to type 316LN and HT-9 stainless steels. Seven creep constants of the model,A, B. k, m, λ, γ, andq were determined for type 316LN stainless steel. In order to quantify a damage parameter, the cavity was interruptedly traced during creep for measuring cavity area to be reflected into the damage equation. For type 316LN stainless steel, λ=ε _R /ε* and λ _f =ε/ε _R were 3.1 and increased with creep strain. The creep curve with λ=3.1 depicted well the experimental data to the full lifetime and its damage curve showed a good agreement whenr=24. However for the HT-9 stainless steel, the values of A and A/ were different as λ=6.2 and λ _f =8.5, and their K-R creep curves did not agree with the experimental data. This mismatch in the HT-9 steel was due to the ductile fracture by softening of materials rather than the brittle fracture by cavity growth. The differences of the values in the above steels were attributed to creep ductilities at the secondary and the tertiary creep stages.     

An analytic study on laminar film condensation along the interior surface of a cave-shaped cavity of a flat plate heat pipe

An analytic approach has been employed to study condensate film thickness distribution inside cave-shaped cavity of a flat plate heat pipe. The results indicate that the condensate film thickness largely depends on mass flow rate and local velocity of condensate. The increasing rate of condensate film for circular region reveals about 50% higher value than that of vertical region. The physical properties of working fluid affect significantly the condensate film thickness, such as the condensate film thickness for the case of FC-40 are 5 times larger than that of water. In comparison with condensation on a vertical wall, the average heat transfer coefficient in the cave-shaped cavity presented 10-15% lower values due to the fact that the average film thickness formed inside the cave-shaped cavity was larger than that of the vertical wall with an equivalent flow length. A correlation formula which is based on the condensate film analysis for the cave-shaped cavity to predict average heat transfer coefficient is presented. Also, the critical minimum fill charge ratio of working fluid based on condensate film analysis has been predicted, and the minimum fill charge ratios for FC-40 and water are about Ψ_crit= 3-7%, Ψ_crit=0.5-1.3%, respectively, in the range of heat fluxq” = 5-90kW/²     

An Increase in the Energy Yield and Giant-Pulse Generation Efficiency in a Laser with Self-injection of the Initiating Radiation

Optical laser systems that ensure generation of giant pulses from a narrow-band initiating free-running oscillation upon change in the Qfactor of the laser cavity and (or) in the amplification factor in it are described. The result of experimental studies of the parameters of a giant-pulse radiation generated by this type of ruby lasers with electrooptical switching of a branched combined cavity are presented.     

Ultrastructure and distribution of superficial neuromasts of blind cavefish,Phreatichthys andruzzii,juveniles

Transmission and scanning electron microscopy (TEM, SEM) were used to study the ultrastructure of superficial neuromasts in 15 six-month old blind cavefish juveniles, Phreatichthys andruzzii (Cyprinidae). In five specimens examined with SEM, the number of superficial neuromasts over the fish body (480–538) was recorded. They were localized mainly on the head (362–410), including the dorsal surface, the mentomandibular region, and laterally from the mouth to the posterior edge of the operculum. Neuromasts were also present laterally on the trunk and near the caudal fin (116–140). A significantly higher number of neuromasts were present on the head compared to the trunk (t-test, P < 0.05). Superficial neuromasts of the head and those along the trunk were similar in ultrastructure. Each neuromast comprised sensory hair cells surrounded by nonsensory support cells (mantle cells and supporting basal cells) with the whole covered by a cupula. Each hair cell was pear-shaped, 15–21 μm high and 4–6 μm in diameter, with a single long kinocilium and several short stereocilia. Most support cells were elongated, with nuclei occupying a large portion of the cytoplasm. In the margin of the neuromast, mantle cells were particularly narrow. Both types of support cells had well-developed Golgi apparatus and rough endoplasmic reticulum. The number of hair cells and nonsensory support cells of the anterior lateral line (head) did not differ significantly from those of the posterior lateral line (trunk) (t-test, P > 0.05). Microsc. Res. Tech. 2009. © 2009 Wiley-Liss, Inc.     

Descriptive studies on the tongue of two micro‐mammals inhabiting the Egyptian fauna; the Nile grass rat (Arvicanthis niloticus) and the Egyptian long‐eared hedgehog (Hemiechinus auritus)

The current study aimed to describe the anatomical features of the tongues of two micro‐mammals common in the Egyptian fauna; the Nile grass rat (Arvicathis niloticus), and the Egyptian long‐eared hedgehog (Hemiechinus auritus). The tongues of five adult individuals of each species were excised and processed histologically, histochemically, and morphometrically. Statistical analysis comparing the relative tongue length in both species showed that there was a significant difference, which may correlate with the difference in feeding preferences. Grossly, the Nile grass rat has a dorsal lingual prominence with bifurcated apex while, the long‐eared hedgehog has a median slight elevation with rounded apex. Numerous forms of mechanical and gustatory papillae are scattered along the lingual dorsal epithelium. The histochemical detection of keratin by Holland's trichrome stain showed an intense expression in the case of A. niloticus and mild expression in H. auritus. The framework of the tongue (entoglossum) is supported by either a core of cartilage in H. auritus or bone in A. niloticus which incorporated in the lingual root. The lingual glands also showed marked variation, the Nile grass rat exhibit dense populations of mucous‐secreting glands and lesser populations of serous‐secreting glands, the contrary is true in H. auritus. In conclusion, the micro and macro‐anatomical features of the tongues of both species showed adaptive changes to accommodate the feeding lifestyle. Such type of studies using mammals from different phylogenetic traits and almost have different feeding preferences provide answers to many research questions related to tongue evolution among mammalian vertebrates.     

Neural network and CFD-based optimisation of square cavity and curved cavity static labyrinth seals

The pressure drop characteristics for leakage of water through circular grooved, square cavity and curved cavity static labyrinth seals are investigated. A semi-theoretical model employing two new terms named virtual cavity velocity and vortex loss coefficient, to determine the pressure drop across the seal is presented. Five different square cavity labyrinth seals (SCLS) were subjected to flow visualisation tests to observe the leakage flow patterns. Computational fluid dynamic (CFD) analysis was done using Fluent commercial code. The values of the vortex loss coefficient for the SCLS at turbulent flow conditions were obtained experimentally. Using the data pool, an artificial neural network (ANN) simulation model was employed to identify the optimal SCLS configuration. Based on the insights gained, two different curved cavity labyrinth seal (CCLS) geometries were developed and optimised using parametric CFD analysis. They were visualisation tested and experimentally found to have higher pressure drops and vortex loss coefficients as compared to the SCLS configurations. The studies show that the enhanced performance is due to the presence of multiple recirculation zones within their cavities, which dissipate higher amount of leakage flow momentum.     

A novel whole tooth-in-jaw-bone culture of rat molars: Morphological, immunohistochemical, and laser capture microdissection analysis

In conventional whole‐tooth culture systems, limitation exists regarding maintenance of the vitality of the dental pulp, because this tissue is encased in rigid dentin walls that hinder nutrition supply. We here report a whole tooth‐in‐jaw‐bone culture system of rat mandibular first molars, where transcardiac perfusion with culture medium was carried out before placement of the jaw bone into culture medium, aiming to facilitate longer time preservation of the dental pulp tissue. Following 7 days of culture, the pulp tissues were analyzed by histology and immunohistochemistry to ED2 (antiresident macrophage). ED2‐positive macrophages were also analyzed for their Class II MHC, interleukin‐6 (IL‐6), and p53 mRNA expression levels by means of immune‐laser capture microdissection (immune‐LCM). Dentin sialophosphoprotein (DSPP) mRNA expression in odontobalstic layer was also examined by LCM. Teeth cultured following saline‐perfusion and nonperfusion served as cultured controls. Normal teeth also served as noncultured controls. Histological examination demonstrated that the structure of the pulp tissue was well preserved in the medium‐perfused explants in contrast to the cultured control groups. The Class II MHC, IL‐6, and p53 mRNA expression levels of ED2‐positive cells and DSPP expression levels of odontoblastic layer tissues in the pulp of medium‐perfused explants were not significantly different from those in the noncultured normal teeth. In conclusion, the structural integrity and mRNA expression in the pulp were maintained at the in vivo level in the ex vivo whole tooth‐in‐jaw‐bone culture system. The system may lay the foundation for studies aiming at defining further histological and molecular mechanism of the pulp. Microsc. Res. Tech. 2012. © 2012 Wiley Periodicals, Inc.     

Comparative immunohistological study on using capsaicin,piperine, and okadaic acid for the transepithelial passage of the inactivated viral and bacterial vaccines in fish

The practical difficulty of parenteral application of fish vaccines against devastating fish diseases diverted the interest toward oral vaccination. Search for effective methods to enhance the oral uptake of viral and bacterial vaccines is continuing. The current research focus on a new role of mucosal fish vaccine adjuvants inducing the antigen uptake by enhancing vascularity or increasing intestinal permeability. Some inflammatory substances cause reversible pathology to the intestinal epithelium, which could be employed for the transepithelial passage of vaccine particles. The natural inflammatory substances used were capsaicin, piperine, and okadaic acid as 1 mg, 2 mg, and 1 μg/fish, respectively. Two inactivated vaccines were used as antigens to test the effect of these inflammatory substances in two different fish hosts. Tested vaccines were inactivated redspotted grouper nervous necrosis virus vaccine in sevenband grouper (Epinephelus septemfasciatus) and inactivated Edwardsiella tarda vaccine in red sea bream (Pagrus major) fish models. The inflammatory substances and each vaccine were anally intubated to fish. Capsaicin proved to be effectively aiding the transepithelial passage of vaccine particles more than piperine, while okadaic acid had no detectable effect.     

Time‐dependent reduction of structural complexity of the buccal epithelial cell nuclei after treatment with silver nanoparticles

Recent studies have suggested that silver nanoparticles (AgNPs) may affect cell DNA structure in in vitro conditions. In this paper, we present the results indicating that AgNPs change nuclear complexity properties in isolated human epithelial buccal cells in a time‐dependent manner. Epithelial buccal cells were plated in special tissue culture chamber / slides and were kept at 37°C in an RPMI 1640 cell culture medium supplemented with L‐glutamine. The cells were treated with colloidal silver nanoparticles suspended in RPMI 1640 medium at the concentration 15 mg L^?1. Digital micrographs of the cell nuclei in a sample of 30 cells were created at five different time steps: before the treatment (controls), immediately after the treatment, as well as 15 , 30 and 60 min after the treatment with AgNPs. For each nuclear structure, values of fractal dimension, lacunarity, circularity, as well as parameters of grey level co‐occurrence matrix (GLCM) texture, were determined. The results indicate time‐dependent reduction of structural complexity in the cell nuclei after the contact with AgNPs. These findings further suggest that AgNPs, at concentrations present in today's over‐the‐counter drug products, might have significant effects on the cell genetic material.     

Numerical analysis of the subsonic flow around a three-dimensional cavity

Flight vehicles such as wheel wells and bomb bays have many cavities. The flow around a cavity is characterized as an unsteady flow because of the formation and dissipation of vortices brought about by the interaction between the free stream shear layer and the internal flow of the cavity. The resonance phenomena can damage the structures around the cavity and negatively affect the aerodynamic performance and stability of the vehicle. In this study, a numerical analysis was performed for the cavity flows using the unsteady compressible three-dimensional Reynolds-Averaged Navier-Stokes (RANS) equation with Wilcox’s turbulence model. The Message Passing Interface (MPI) parallelized code was used for the calculations by PC-cluster. The cavity has aspect ratios (L/D) of 2.5 ∼ 7.5 with width ratios (W/D) of 2 ∼ 4. The Mach and Reynolds numbers are 0.4 ∼ 0.6 and 1.6×10 ⁶ , respectively. The occurrence of oscillation is observed in the “shear layer and transient mode” with a feedback mechanism. Based on the Sound Pressure Level (SPL) analysis of the pressure variation at the cavity trailing edge, the dominant frequencies are analyzed and compared with the results of Rossiter’s formula. The dominant frequencies are very similar to the result of Rossiter’s formula and other experimental data in the low aspect ratio cavity (L/D = ∼ 4.5). In the large aspect ratio cavity, however, there are other low dominant frequencies due to the leading edge shear layer with the dominant frequencies of the feedback mechanism. The characteristics of the acoustic wave propagation are analyzed using the Correlation of Pressure Distribution (CPD). This paper was recommended for publication in revised form by Associate Editor Do Hyung Lee Hong-il CHOI received the B.S and M.S degrees in Aerospace Engineering from Chosun University, Korea in 2005 and 2008, respectively. He currently work at KOREA Electric Power Research Institute in Korea Pa-ul MUN received the B.S in Aerospace Engineering from Chosun University, Korea in 2008. He is currently Candidate for the degree of master of Aerospace Engineering at Chosun University in Korea. Jae-soo KIM received the B.S in Aerospace Engineering from Seoul National University in Korea in 1981. He then received his M.S and Ph.D. degree in Aerospace Engineering from KAIST in Korea in 1983 and 1987, respectively. He spent one year at Cornell university(USA) as a Post Doc. He worked at Korea Aerospace Research Institute for eight years. Dr. Kim is currently a Professor at the Department of Aerospace Engineering at Chosun University in Korea