Granular Inclusions Research Articles

Microstructure and tensile properties of the laser welded TWIP steel and the deformation behavior of the fusion zone

Abstract Microstructure and tensile properties of the laser welded joint of Fe–18.8Mn–0.6C TWIP steel were investigated in this research. The microstructure of fusion zone (FZ) was characterized by means of X-ray diffraction (XRD), transmission electron microscope (TEM) and scanning electron microscope (SEM). TEM and in-situ SEM observation were employed to investigate the microstructural evolution and strengthening mechanism of FZ during deformation. The welded joint with a fully austenitic structure was obtained by the laser welding. The granular divorced eutectic phases (Fe, Mn)3C and inclusions formed in the interdendritic regions during the solidification of FZ. The fully austenitic structure and coarse dendrite grains were responsible for the fracture at the weld seam. The FZ exhibited a good combination of strength (e.g. tensile strength up to 1000 MPa) and ductility (e.g. total elongation up to 73%). The microstructural evolution revealed that dislocation slip was the main deformation mechanism at low strains of FZ, while at relatively high strains, mechanical twinning was the domain deformation mechanism and played an important role in improving the strength and ductility as well as the work-hardening effect of FZ.

Malakoplakia of the Thyroid Gland

Malakoplakia is a rare granulomatous disease that most commonly occurs in the urinary tract. It is characterized by sheets of histiocytes with granular basophilic inclusions and Michaelis-Gutmann bodies. We present an exceedingly rare case of malakoplakia of the thyroid in a 54-year-old Caucasian woman on immunosuppressive therapy for renal transplant performed in 1994.

Apatite, SiO2, rutile and orthopyroxene precipitates in minerals of eclogite xenoliths from Yakutian kimberlites, Russia

Eclogite mantle xenoliths from the central part of Siberian craton (Udachnaya and Zarnitsa kimberlite pipes) as well as from the northeastern edge of the craton (Obnazhennaya kimberlite) were studied in detail. Garnet and clinopyroxene show evident exsolution textures. Garnet comprises rutile, ilmenite, apatite, and quartz/coesite oriented inclusions. Clinopyroxene contains rutile (±ilmenite) and apatite precipitates. Granular inclusions of quartz in kyanite and garnet usually retain features of their high-pressure origin. According to thermobarometric calculations, the studied eclogitic suite was equilibrated within lithospheric mantle at 3.2–4.9GPa and 813–1080°C. The precursor composition of garnets from Udachnaya and Zarnitsa eclogites suggests their stability at depths 210–260km. Apatite precipitation in clinopyroxenes of Udachnaya and Zarnitsa allows us to declare that original pyroxenes could have been indicative of their high P–T stability. Raman spectroscopic study of quartz and coesite precipitates in garnet porphyroblasts confirms our hypothesis on the origin of the exsolution textures during pressure–temperature decrease. With respect to mineralogical data, we suppose the rocks to be subjected to stepwise decompression and cooling within mantle reservoir.

홍합 (Mytilus coruscus) 족사 cuticle의 초미세구조 연구

Mussel byssus is a bundle of threads used to attach mussels to wet substrates. Recently, a thin cuticle layer on the byssus has attracted public attentions due to its remarkable toughness - stiff as epoxy resin and extensible as rubber. Here, we observed ultrastructure of the cuticle layer in a far eastern mussel (Mytilus coruscus) to understand underlying mechanisms for the mechanical properties. The cuticle layer observed by TEM was composed of submicron-sized granular inclusions in a continuous matrix phase. In addition, ultrastructural study in the presence of tertiary amine (Tetraethylammonium, TEA) showed an evidence that the cuticle is stabilized by cation-<TEX>${\pi}$</TEX> interaction.

Ultrastructure and histochemistry of the periplasm in oocytes of sturgeons during egg envelope formation.

In the cytoplasm of oocytes (ooplasm) located in ovarian follicles with diameters 2000 microm and 2150 microm in Acipenser gueldenstaedtii, and 2000 microm and 2350 microm in A. baerii, periplasm containing a basophilic compartment and endoplasm containing reserve materials was formed. Vesicles involved in polyspermy blocking and in the formation of the embryo were located in the periplasm. These included compact (cCGs), low-electron-dense cortical granules (lCGs), and lamellar bodies. The cCGs were bounded by a membrane, comprised fibrillar material, fibrils and rod-shaped components. The lCGs were membrane-bounded and contained fibrillar material and granular inclusions. Endoplasmic reticulum (ER) and Golgi complexes were involved in the formation of cCG and lCG. The basophilic compartment, ER and Golgi vesicles participated in the formation of lamellar bodies. They comprised numerous membranes and fibrillar material. It is assumed that they transfer membranes and their precursors to the growing furrow during cleavage and release their content to organize the extracellular matrix. The location of compounds in the developing egg envelope of A. gueldenstaedtii was presented and discussed. Ovaries of both investigated species represented the first pubertal stages of development. Such fish should not be used for reproduction.

Novel liver findings in Ornithine Transcarbamylase Deficiency due to Xp11.4-p21.1 microdeletion

Ornithine transcarbamylase deficiency (OTCD, OMIM 311250), the most common urea cycle disorder, results in impaired synthesis of citrulline from carbamoyl phosphate and ornithine. Individuals have been identified with OTCD due to a contiguous gene deletion at Xp11.4-p21.1 and unique clinical features, described as the “extended OTCD phenotype”. We present a male with neonatal-lethal OTCD due to a 1.87Mb microdeletion at Xp11.4-p21.1 (37126841-38998991 hg18). Autopsy revealed a novel histological finding of hepatocyte globular and granular inclusions. Such inclusions have not been described in OTCD or other metabolic disorders and are not an associated finding in neonatal liver failure due to other causes. The deleted region includes the gene SYTL5, potentially involved in RAB27A-dependent membrane trafficking in the liver and placenta. We propose that the contiguous gene deletion could contribute to the severity of the clinical presentation here and hypothesize that deletion of SYTL5 could contribute to the liver findings.

Cytological changes during luminescence production in lanternshark (Etmopterus spinax Linnaeus, 1758) photophores

Studying an organism’s photogenic structures at the ultrastructural level is a key step in the understanding of its light-emission process. Recently, the photophore ultrastructure of the deep-sea lanternshark Etmopterus spinax Linnaeus, 1758 was described. The photocytes appeared to be divided into three areas including an apical granular area, which contains inclusions and was hypothesized to be the light-producing reaction site. In this study, we investigated the morphological changes occurring within the granular area during the bioluminescent emissions induced by two hormones: prolactin and melatonin. Prolactin provoked the formation of new structures in the granular area, the “grey particles”, whose number was proportional to the amount of light produced by the reaction. An increase in the number of granular inclusions was also detected at the end of the prolactin-induced light emission. Conversely, melatonin induced a decrease in the number of granular inclusions and an increase in their diameter. An effect of hormones was also observed on the iris-like structure where they triggered pigment retraction and hence an increase in the iris aperture diameter. This is consistent with previous findings and is shown for the first time at the cellular level. The possible role of grey particles in E. spinax light-emission mechanism is discussed, while granular inclusion is considered to be E. spinax’s intracellular luminescence site. Regarding typical shark long-lasting glows, a new term (“glowon”) is proposed to characterize this novel membrane-free microsource.

BIOLOGICAL, MOLECULAR AND IMMUNOCYTOCHEMICAL CHARACTERIZATION OF CELL CULTURE ADAPTED HUMAN ROTAVIRUS STRAINS DETECTED IN THE CITY OF PONTA GROSSA, PARANA, BRAZIL

Rotaviruses (RV) are the single most important cause of severe diarrheal illness in infants and young children in both developed and developing countries worldwide. They affect mainly children less than 24 months of age. Presently, we adapted human rotavirus strains from field materials in cell culture, as well as, studied their properties by the analyses of the cytopathic effect, immunofluorescence features, plaque properties and virus genome stability. The study was carried out with 53 rotavirus-positive fecal specimens, collected in the city of Ponta Grossa, Parana, before the introduction of vaccination program in Brazil. The samples were submitted to at least 3 blind passages in MA-104 cell culture before discarded as non-cultivable. The adaptation process was monitored by the development of the cytopathic effect, immunofluorescence assay , plaque assay and genome stability by reverse transcriptase-polymerase chain reactions amplification. Fourteen human rotavirus strains were adapted to grow in cell culture. The isolation was demonstrated by the development of typical cytopathic effect. Immunofluorescence assay revealed granular inclusions with specific fluorescence mainly at the perinuclear area of the infected cells. Plaque assay allowed the demonstration of plaques with varying diameter depending upon the strains. Reverse transcriptase-polymerase chain reactions resulted in amplification and genotyping, demonstrating the stability of the genome through cell culture adaptation. DOI: http://dx.doi.org/10.17525/vrr.v19i1.97

Ultrastructural organization of lantern shark (Etmopterus spinax Linnaeus, 1758) photophores

Etmopterus spinax Linnaeus, 1758 is a deepsea lantern shark that emits blue light thanks to thousands of tiny cup-shaped organs made of a pigmented sheath enclosing light-emitting cells topped by an iris-like structure and a lens. In this study, we investigate the ultrastructure of these photophores in order to improve our understanding of the light emission process. The presence of a novel layer, a putative reflector upholstering the pigmented sheath, is highlighted. The intracellular organization of the photocytes is addressed. They appear as regionalized cells: their basal area is occupied by an ovoid nucleus, their medial area is highly vesiculated and their apical area, oriented toward the photophore center, displays small granular inclusions. We hypothesize this granular area to be the intracellular site of photogenesis in E. spinax, as it is also the most fluorescent part of the photocyte.

Granular bodies in root primary meristem cells of Zea mays L. var. Cuscoensis K. (Poaceae) that enter young vacuoles by invagination: a novel ribophagy mechanism

Because it has a very large, very rapidly growing primary root, we evaluated giant maize (Zea mays var. Cuscoensis) as a model organism for root research. Granular inclusions are a common feature of cells in many organisms, but they are not common in root meristems. We here report the presence of granules in root tip cells of giant maize. Seeds were germinated at 20°C in sterile conditions. Four to 5-day-old primary roots were fixed, embedded, and sectioned for light and electron microscopy. Granules (1-2μm) were observed in small vacuoles in all cell types of the apical meristem zone and mainly in parenchyma cells of the procambium in the primary meristem zone. Some sections were treated with ribonuclease and/or proteinase and then stained with toluidine blue, methyl green pyronin, or Coomassie brilliant blue. The results were used to determine that the granules were composed primarily of RNA and protein. In electron micrographs, consistent with the enzyme experiment results, granules appeared to be dense aggregates of polyribosomes and rough endoplasmic reticulum. They formed first in the cytosol, then invaginated into an adjacent vacuole. The granules are apparently ephemeral and therefore may not have a function other than being subject to autolysis. We speculate that they are part of a previously undescribed ribophagy system that operates during rapid cell growth and differentiation to regulate translation and recycle granule components.

Brain involvement by leprosy presenting as a frontal cystic lesion

Leprosy has a predilection for peripheral nerves and is not considered to involve the CNS. The idea that the CNS is exempt from Mycobacterium leprae bacilli has been suspected from a clinical perspective or CSF study in leprosy patients. However, there has been no direct evidence for CNS involvement by leprosy in a living patient. To the best of the authors' knowledge, the present case is the first report providing histopathological and molecular evidence for CNS involvement by leprosy in a living patient. Brain MRI revealed a 2-cm cystic lesion in the right frontal lobe of the patient. The medical history revealed that the patient had been receiving multidrug therapy for borderline lepromatous leprosy. Neuronavigation-guided craniotomy and lesion removal were performed due to a presumptive diagnosis of low-grade glioma. The brain specimen demonstrated variably thickened blood vessels and densely scattered foamy macrophages in the perivascular spaces and parenchymal stroma. Fite acid-fast stain displayed red granular inclusions that were suggestive for fragmented M. leprae. M. leprae-specific nested polymerase chain reaction amplification showed positive bands, and DNA sequencing also demonstrated homology with the M. leprae genome. This case supports the notion that M. leprae can involve the cerebral cortex regardless of cranial nerve engagement.

Ground Engineering with Granular Inclusions for Loose Saturated Sands Subjected to Seismic Loadings

Sites having predominant loose sand deposits are prone to many hazards, especially under seismic loading conditions. Among different forms of seismic risks, liquefaction is being considered as a crucial hazard when the deposit is saturated/with high ground water level. Ground improvement methods are commonly employed to improve the natural site conditions under such situations for better performance of various engineering structures. Ground treatment by granular inclusions in columnar form can offer effective solution than most other ground improvement methods. This paper presents the review of various aspects of ground engineering of loose saturated sands with granular piles/stone columns. A short discussion on the seismic hazards associated with loose sand deposits with main focus on liquefaction followed by the outlines of the recent developments on the application of granular inclusions in the form of stone columns/granular piles as general ground improvement method as well as seismic hazard mitigation measure are presented. New design charts are developed based on pore pressure generation and dissipation considering various installation and behavioral effects and are discussed and compared with the original design curves. It is concluded that the granular inclusions are very effective in resisting the effects of seismic loading on loose saturated sands. It is also recommended to consider various affects of the granular inclusions together while designing the ground engineering system.

A nonlinear meso–macro approach to modelling delayed ettringite formation and concrete degradation

We show how a two-scales FE model—within a sequential approach—leads to consistently simulate the DEF macroscopic consequences: cracks pattern and opening, residual modulus decrease. The mesoscopic part of this model is adapted to heterogeneous materials and is based on two kinematics enrichments. The first one leads to a very fast meshing process along the randomly chosen set of aggregates and, the second leads to directly compute the cracks openings. Assuming DEF is driving to a progressive and homogeneous mortar expansion, we show how the macroscopic—concrete—expansion as well the cracks pattern are consistent with the experiments. For the latter we are interested in the characterization of the aggregates effect on the amplitude of DEF swelling, so that we focus on parameters such as the size and the volume fraction of granular inclusions.

Permeability of microscale fibrous porous media using the lattice Boltzmann method

The permeabilities of microscale fibrous porous media were calculated using the multiple-relaxation-time (MRT) lattice Boltzmann method (LBM). Two models of the microscale fibrous porous media were constructed based on overlapping fibers (simple cubic, body-centered cubic). Arranging the fibers in skew positions yielded two additional models comprising non-overlapping fibers (skewed simple cubic, skewed body-centered cubic). As the fiber diameter increased, the fibers acted as granular inclusions. The effects of the overlapping fibers on the media permeability were investigated. The overlapping fibers yielded permeability values that were a factor of 2.5 larger than those obtained from non-overlapping fibers, but the effects of the fiber arrangement were negligible. Two correlations were obtained for the overlapping and non-overlapping fiber models, respectively. The effects of the rarefaction and slip flow are also discussed. As the Knudsen number increased, the dimensionless permeability increased; however, the increase differed depending on the fiber arrangement. In the slip flow regime, the fiber arrangement inside the porous media became an important factor.

Characterization of a planctomycete associated with the marine dinoflagellate Prorocentrum micans Her

During attempts to obtain axenic the cultures of the marine dinoflagellate Prorocentrum micans, a microorganism with peculiar features was isolated. This contaminant resisted the physical and antibiotic treatments performed. Subsequent characterization showed that in agar plates this microorganism develops round granular pink colonies. It is a salt-dependent mesophilic and chemoheterotrophic Gram negative bacterium with a rod to ovoid shape, presenting cell motility in young cultures. Cell division occurs by cell budding. The bacterium forms aggregates with a variable number of cells that are stacked by fibrillar glycoproteic material, the holdfast. A tuft of numerous short glycoproteic fimbriae emerges from one pole of the cell. Preeminent granular inclusions, also of glycoproteic nature, are present in the cytoplasm. Several structural and compositional aspects of the cell envelope and cytoplasm are provided. The production of fibrillar material and the existence of the polar appendages suggest that this microorganism should occur in aquatic environments bound to substrates and could be associated with P. micans in natural marine habitats. Based on the characteristics displayed, this microorganism is a member of the Planctomycetes, order Planctomycetales.

Megalocytivirus infection in orbiculate batfish Platax orbicularis

Megalocytiviruses cause systemic disease in both marine and freshwater fishes, negatively impacting ornamental and food fish aquaculture. In this report, we characterize a megalocytivirus infection in a captive marine ornamental fish, the orbiculate batfish Platax orbicularis. Histologic examination revealed cytomegalic cells characterized by strongly basophilic granular intracytoplasmic inclusions within various organs. Transmission electron microscopy revealed icosahedral virus particles within the cytoplasm of cytomegalic cells consistent with an iridovirus infection. Analysis of the major capsid protein gene sequence confirmed that the orbiculate batfish virus is a member of the family Iridoviridae and is identical to the only other megalocytivirus reported from a marine ornamental fish, the Banggai cardinalfish Pterapogon kauderni iridovirus.

New model for the genesis and maturation of viroplasms induced by fijiviruses in insect vector cells.

Plant reoviruses are thought to replicate and assemble within cytoplasmic, nonmembranous structures called viroplasms. Here, we established continuous cell cultures of the white-backed planthopper (Sogatella furcifera Horváth) to investigate the mechanisms for the genesis and maturation of the viroplasm induced by Southern rice black-streaked dwarf virus (SRBSDV), a fijivirus in the family Reoviridae, during infection of its insect vector. Electron and confocal microscopy revealed that the viroplasm consisted of a granular region, where viral RNAs and nonstructural proteins P6 and P9-1 accumulated, and a filamentous region, where viral RNAs, progeny cores, viral particles, as well as nonstructural proteins P5 and P6 accumulated. Our results suggested that the filamentous viroplasm matrix was the site for the assembly of progeny virions. Because viral RNAs were produced by assembled core particles within the filamentous viroplasm matrix, we propose that these viral RNAs might be transported to the granular viroplasm matrix. P5 formed filamentous inclusions and P9-1 formed granular inclusions in the absence of viral infection, suggesting that the filamentous and granular viroplasm matrices were formed primarily by P5 and P9-1, respectively. P6 was apparently recruited in the whole viroplasm matrix by direct interaction with P9-1 and P5. Thus, the present results suggested that P5, P6, and P9-1 are collectively required for the genesis and maturation of the filamentous and granular viroplasm matrix induced by SRBSDV infection. Based on these results, we propose a new model to explain the genesis and maturation of the viroplasms induced by fijiviruses in insect vector cells.

Influence of aggregate shapes on drying and carbonation phenomena in 3D concrete numerical samples

This study aims at generating numerical 3D samples of concrete so as to study the effects of the granular inclusions shape on the macroscopic kinetics of reactive transport phenomena. Two types of mesostructure configurations are considered: the first one is composed of a matrix of mortar in which are randomly distributed inclusions corresponding to the concrete coarse aggregates, and the second one also includes a steel rebar. The choice of a mesoscopic modeling for the mortar matrix is based on the need to obtain numerical structures of reasonable size. In particular, the Interfacial Transition Zones (ITZs) are assumed to be incorporated into the homogenized mortar properties. This study is applied to the case of drying and atmospheric carbonation by using simplified models solved by the finite element code Cast3M. The purpose is to quantify the influence of the aggregate shape on the kinetics of macroscopic transfer and the isovalue lines for some physical variables representative of the reactive transport problems: saturation degree for drying, and porosity, calcite and portlandite concentrations for carbonation. Basic aggregates shapes are studied (spheres, cubes), as well as more complex ones (Voronoi particles) which are supposed to be more representative of real aggregates. The effects of ‘non-isotropic’ shapes (oblate and prolate ones) are also investigated. It is shown that the influence of the aggregate shapes appears negligibly small on macroscopic indicators, except for oblate shapes with aspect ratios of 3. This latter case also exhibits substantial local delayed effects and a more important variability, which may have some importance for a precise description and estimation of degradation processes related to steel rebar corrosion.

Preparation of Zein Conjugated Quantum Dots and Their &lt;I&gt;In&lt;/I&gt; &lt;I&gt;Vivo&lt;/I&gt; Transdermal Delivery Capacity Through Nude Mouse Skin

Zein have been successfully conjugated with quantum dots (QD630) via N-(3-dimethylaminopropyl)-N(-ethyl-carbodiimide hydrochloride (EDC) coupling. Transmission electron microscopy (TEM) and dynamic light scattering (DLS) measurements indicated that the average diameter of QD630 was about 5 nm, and that of the zein conjugated QD630 (QD630/Zein) increased to 24 nm. Their size distributions were relatively narrow (Polyindex (PI) < 0.15). The FT-IR and electrophoresis results indicated that QD630 has been combined with zein covalently. Uptakes of QD630 and QD630/Zein by NIH3T3 cells showed different kinetics as observed by fluorescent microscope. There was no obvious increase of fluorescent intensity within cells after 1 h for QD630 sample, while for QD630/Zein, uptake was found to be continuously increased and the major portion of QD630/Zein was localized in the perinuclear area in the form of granular inclusions at 9 h and 24 h. Moreover, penetrating ability of QD630 and QD630/Zein into skin was evaluated with nude mouse in vivo. Fluorescence images revealed that tiny QD630 particles penetrated through the stratum corneum barrier and localized within the epidermal and dermal layers by 8 h, and no QDs was found after 24 h; whereas for QD630/Zein particles, no obvious penetration was observed within 24 hours. Modification of conjugated zein to QDs may alter their skin penetration characteristics and reduce the risk of the QD toxicity.

Structures in compressible magnetoconvection and the nature of umbral dots

Structures seen in idealized numerical experiments on compressible magnetoconvection in an imposed strong vertical magnetic field show important differences from those detected in observations or realistic numerical simulations of sunspot umbrae. To elucidate the origin of these discrepancies, we present a series of idealized 3D compressible magnetoconvection experiments that differ from previous such experiments in several details, bringing them closer to realistic solar conditions. An initially vertical magnetic field B 0 is imposed on a time snapshot of fully developed solar-like turbulent convection in a layer bounded by a stable layer from above. Upon relaxation to a statistically steady state, the structure of the flow field and magnetic field is examined. Instead of the vigorous granular convection (GRC) well known to take place in magnetized or weakly magnetized convection, for high values of B0 heat is transported by small-scale convection (SSC) in the form of narrow, persistent convective columns consisting of slender upflows accompanied by adjacent downflow patches, which are reminiscent of the 'convectons' identified in earlier semianalytic models. For moderate field strengths, flux separation (FXS) is observed: isolated field-free inclusions of GRC are embedded in a strongly magnetized plasma with SSC. Between the SSC and FXS regimes, a transitional regime (F/S) is identified where convectons dynamically evolve into multiply segmented granular inclusions and back. Our results agree in some aspects more closely with observed umbral structures than earlier idealized models, because they do reproduce the strong localized, patchy downflows immediately adjacent to the narrow convective columns. Based on recent observations of umbral dots, we suggest that in some cases the conditions in sunspot umbrae correspond to the newly identified F/S transitional regime.