Increased matriptase zymogen activation in inflammatory skin disorders

PubMed Central

Chen, Cheng-Jueng; Wu, Bai-Yao; Tsao, Pai-In; Chen, Chi-Yung; Wu, Mei-Hsuan; Chan, Yee Lam E.; Lee, Herng-Sheng; Johnson, Michael D.; Eckert, Richard L.; Chen, Ya-Wen; Chou, Fengpai; Lin, Chen-Yong

2011-01-01

Matriptase, a type 2 transmembrane serine protease, and its inhibitor hepatocyte growth factor activator inhibitor (HAI)-1 are required for normal epidermal barrier function, and matriptase activity is tightly regulated during this process. We therefore hypothesized that this protease system might be deregulated in skin disease. To test this, we examined the level and activation state of matriptase in examples of 23 human skin disorders. We first examined matriptase and HAI-1 protein distribution in normal epidermis. Matriptase was detected at high levels at cell-cell junctions in the basal layer and spinous layers but was present at minimal levels in the granular layer. HAI-1 was distributed in a similar pattern, except that high-level expression was retained in the granular layer. This pattern of expression was retained in most skin disorders. We next examined the distribution of activated matriptase. Although activated matriptase is not detected in normal epidermis, a dramatic increase is seen in keratinocytes at the site of inflammation in 16 different skin diseases. To gain further evidence that activation is associated with inflammatory stimuli, we challenged HaCaT cells with acidic pH or H2O2 and observed matriptase activation. These findings suggest that inflammation-associated reactive oxygen species and tissue acidity may enhance matriptase activation in some skin diseases. PMID:21123732

MicroRNAs Promote Granule Cell Expansion in the Cerebellum Through Gli2.

PubMed

Constantin, Lena; Wainwright, Brandon J

2015-12-01

MicroRNAs (miRNAs) are important regulators of cerebellar function and homeostasis. Their deregulation results in cerebellar neuronal degeneration and spinocerebellar ataxia type 1 and contributes to medulloblastoma. Canonical miRNA processing involves Dicer, which cleaves precursor miRNAs into mature double-stranded RNA duplexes. In order to address the role of miRNAs in cerebellar granule cell precursor development, loxP-flanked exons of Dicer1 were conditionally inactivated using the granule cell precursor-specific Atoh1-Cre recombinase. A reduction of 87% in Dicer1 transcript was achieved in this conditional Dicer knockdown model. Although knockdown resulted in normal survival, mice had disruptions to the cortical layering of the anterior cerebellum, which resulted from the premature differentiation of granule cell precursors in this region during neonatal development. This defect manifested as a thinner external granular layer with ectopic mature granule cells, and a depleted internal granular layer. We found that expression of the activator components of the Hedgehog-Patched pathway, the Gli family of transcription factors, was perturbed in conditional Dicer knockdown mice. We propose that loss of Gli2 mRNA mediated the anterior-restricted defect in conditional Dicer knockdown mice and, as proof of principle, were able to show that miR-106b positively regulated Gli2 mRNA expression. These findings confirm the importance of miRNAs as positive mediators of Hedgehog-Patched signalling during granule cell precursor development.

Three-dimensional cultured glioma cell lines

NASA Technical Reports Server (NTRS)

Gonda, Steve R. (Inventor); Marley, Garry M. (Inventor)

1991-01-01

Three-dimensional glioma spheroids were produced in vitro with size and histological differentiation previously unattained. The spheroids were grown in liquid media suspension in a Johnson Space Center (JSC) Rotating Wall Bioreactor without using support matrices such as microcarrier beads. Spheroid volumes of greater than 3.5 cu mm and diameters of 2.5 mm were achieved with a viable external layer or rim of proliferating cells, a transitional layer beneath the external layer with histological differentiation, and a degenerative central region with a hypoxic necrotic core. Cell debris was evident in the degenerative central region. The necrotics centers of some of the spheroids had hyaline droplets. Granular bodies were detected predominantly in the necrotic center.

Disinfection of bacteria attached to granular activated carbon.

PubMed Central

LeChevallier, M W; Hassenauer, T S; Camper, A K; McFeters, G A

1984-01-01

Heterotrophic plate count bacteria, coliform organisms, and pathogenic microorganisms attached to granular activated carbon particles were examined for their susceptibility to chlorine disinfection. When these bacteria were grown on carbon particles and then disinfected with 2.0 mg of chlorine per liter (1.4 to 1.6 mg of free chlorine residual per liter after 1 h) for 1 h, no significant decrease in viable counts was observed. Washed cells attached to the surface of granular activated carbon particles showed similar resistance to chlorine, but a progressive increase in sublethal injury was found. Observations made by scanning electron microscope indicated that granular activated carbon was colonized by bacteria which grow in cracks and crevices and are coated by an extracellular slime layer. These data suggest a possible mechanism by which treatment and disinfection barriers can be penetrated and pathogenic bacteria may enter drinking water supplies. Images PMID:6508306

Ultrastructure of the endolymphatic sac in the larva of the japanese red-bellied newt Cynops pyrrhogaster

NASA Technical Reports Server (NTRS)

Gao, W.; Wiederhold, M.; Hejl, R.

1998-01-01

The ultrastructure of the endolymphatic sac (ES) of the late stage larva of the Japanese red-bellied newt, Cynops pyrrhogaster (stage 57), was examined by light and transmission electron microscopy. The two endolymphatic sacs are located at the dorsal-medial side of the otic vesicle on the dorsal-lateral side of the midbrain in the cranial cavity. The wall of the sac is composed of a layer of cubical epithelial cells with loose, interposed intercellular spaces. The sac contains a large luminal cavity, in which endolymph and numerous otoconia are present. The epithelial cells of different portions of the sac have a similar structure. These cells contain an abundance of cytoplasmic organelles, including ribosomes, Golgi complexes, and numerous vesicles. Two types of vesicles are found in the epithelial cells: the "floccular" vesicle and the "granular" vesicle. The floccular vesicles are located in the supra- and lateral-nuclear cytoplasm and contain floccular material. The granular vesicles have a fine granular substance and are usually situated apposed to the apical cell membrane. The granular vesicles are suggested to be secreted into the lumen, while the floccular vesicles are thought to be absorbed from the lumen and conveyed to the intercellular spaces by the epithelial cells. The apical surfaces of the epithelial cells bear numerous microvilli. Apparently floating cells, which bear long microvilli on the free surfaces, are observed in the lumen of the ES. Based on the fine structure, the function of the endolymphatic sac of the newt Cynops pyrrhogaster is discussed.

Modeling Tsunami Wave Generation Using a Two-layer Granular Landslide Model

NASA Astrophysics Data System (ADS)

Ma, G.; Kirby, J. T., Jr.; Shi, F.; Grilli, S. T.; Hsu, T. J.

2016-12-01

Tsunamis can be generated by subaerial or submarine landslides in reservoirs, lakes, fjords, bays and oceans. Compared to seismogenic tsunamis, landslide or submarine mass failure (SMF) tsunamis are normally characterized by relatively shorter wave lengths and stronger wave dispersion, and potentially may generate large wave amplitudes locally and high run-up along adjacent coastlines. Due to a complex interplay between the landslide and tsunami waves, accurate simulation of landslide motion as well as tsunami generation is a challenging task. We develop and test a new two-layer model for granular landslide motion and tsunami wave generation. The landslide is described as a saturated granular flow, accounting for intergranular stresses governed by Coulomb friction. Tsunami wave generation is simulated by the three-dimensional non-hydrostatic wave model NHWAVE, which is capable of capturing wave dispersion efficiently using a small number of discretized vertical levels. Depth-averaged governing equations for the granular landslide are derived in a slope-oriented coordinate system, taking into account the dynamic interaction between the lower-layer granular landslide and upper-layer water motion. The model is tested against laboratory experiments on impulsive wave generation by subaerial granular landslides. Model results illustrate a complex interplay between the granular landslide and tsunami waves, and they reasonably predict not only the tsunami wave generation but also the granular landslide motion from initiation to deposition.

[Effects of Liangxue Jiedu Decoction in treating psoriasis in a mouse psoriasis model].

PubMed

Gu, Min-Jie; Gao, Shang-Pu; Li, Yong-Mei

2009-06-01

To study the effects of Liangxue Jiedu Decoction, a compound traditional Chinese herbal medicine with the function of blood-cooling and detoxicating, in treating psoriasis in mice and to explore its mechanism. (1) Sixty mice were randomly divided into Liangxue Jiedu Decoction group, compound Indigo Naturalis capsule group, acitretin capsule group and normal saline group. Another 10 mice were selected as blank control. After 2-week administration, mice were sacrificed to obtain samples. After hematoxylin and eosin (HE) staining, tail scales with granular layers were calculated by an optical microscope. (2) Except for ten mice in blank group, sixty female mice were injected intraperitoneally with diethylstilbestrol once daily. After 3-day injection, mice were randomly divided into four groups and treated as above description. After 2-week treatment, all mice were injected intraperitoneally with colchicine (2 mg/kg), and sacrificed 6 h after the injection. The mitotic rate in virginal epithelium was calculated after HE staining. Compared with normal saline, Liangxue Jiedu Decoction could significantly inhibit the mitosis of mouse vaginal epithelium (P < 0.01) and promote the formation of granular layers in mouse tail-scale epidermis (P < 0.01). The mechanism of Liangxue Jiedu Decoction in treating psoriasis may be related to promoting granular cell growth and inhibiting proliferation of epidermic cells.

From cell extracts to fish schools to granular layers: the universal hydrodynamics of self-driven systems

NASA Astrophysics Data System (ADS)

Ramaswamy, Sriram

2007-03-01

Collections of self-driven or ``active'' particles are now recognised as a distinct kind of nonequilibrium matter, and an understanding of their phases, hydrodynamics, mechanical response, and correlations is a vital and rapidly developing part of the statistical physics of soft-matter systems far from equilibrium. My talk will review our recent results, from theory, simulation and experiment, on order, fluctuations, and flow instabilities in collections of active particles, in suspension or on a solid surface. Our work, which began by adapting theories of flocking to include the hydrodynamics of the ambient fluid, provides the theoretical framework for understanding active matter in all its diversity: contractile filaments in cell extracts, crawling or dividing cells, collectively swimming bacteria, fish schools, and agitated monolayers of orientable granular particles.

Gas stream clean-up filter and method for forming same

DOEpatents

Mei, Joseph S.; DeVault, James; Halow, John S.

1993-01-01

A gas cleaning filter is formed in-situ within a vessel containing a fluidizable bed of granular material of a relatively large size fraction. A filter membrane provided by a porous metal or ceramic body or such a body supported a perforated screen on one side thereof is coated in-situ with a layer of the granular material from the fluidized bed by serially passing a bed-fluidizing gas stream through the bed of granular material and the membrane. The layer of granular material provides the filtering medium for the combined membrane-granular layer filter. The filter is not blinded by the granular material and provides for the removal of virtually all of the particulates from a process gas stream. The granular material can be at least partially provided by a material capable of chemically reacting with and removing sulfur compounds from the process gas stream. Low level radioactive waste containing organic material may be incinerated in a fluidized bed in communication with the described filter for removing particulates from the gaseous combustion products.

Construction and characterization of human oral mucosa equivalent using hyper-dry amniotic membrane as a matrix.

PubMed

Qi, Fangfang; Yoshida, Toshiko; Koike, Takeshi; Aizawa, Hitoshi; Shimane, Tetsu; Li, Yinghui; Yamada, Shinichi; Okabe, Motonori; Nikaido, Toshio; Kurita, Hiroshi

2016-05-01

Human amniotic membrane(HAM) as a graft material has been used in various fields. Hyper-dry amniotic membrane (HD-AM) is a novel dried amniotic membrane that is easy to handle and can be preserved at room temperature without time limitation. The purpose of this study was to investigate the useful properties of HD-AM in reconstruction of the oral mucosa. Human oral keratinocytes were isolated and seeded on HD-AM in serum-free culture system. Oral mucosa equivalent (OME) was developed and transplanted onto full-thickness wound on athymic mice. The wound healing was analyzed and the OME both before and after transplantation was analyzed with hematoxylin-eosin staining and immunohistochemical staining for Cytokines 10 (CK10), Cytokines 16 (CK16), and Ivolucrin (IVL). Oral keratinocytes spread and proliferated well on HD-AM. Two weeks after air-lifting, OME had formed with good differentiation and morphology. We confirmed immunohistochemically that the expression of CK10 was positive in all suprabasal layers, as was CK16 in the upper layers, while IVL was present in all cell layers. Three weeks after transplantation to athymic mice, the newly generated tissue had survived well with the smallest contraction. The epithelial cells of newly generated tissue expressed CK10 throughout in all suprabasal layers, IVL was mainly in the granular layer, and CK16 positive cells were observed in all spinous layer and granular layer but were not expressed in the mouse skin, all of which were similar to native gingival mucosa. The OME with HD-AM as a matrix revealed a good morphology and stable wound healing. This study demonstrates that HD-AM is a useful and feasible biomaterial for oral mucosa reconstruction. Copyright © 2016 Elsevier Ltd. All rights reserved.

Somatic sensory cortex (SmI) of the prosimian primate Galago crassicaudatus: organization of mechanoreceptive input from the hand in relation to cytoarchitecture.

PubMed

Carlson, M; Welt, C

1980-01-15

Mechanoreceptive input from the hand to the somatic sensory cortex (SmI) of the prosimian primate Galago crassicaudatus was examined with microelectrode mapping methods. In anesthetized animals, low threshold cutaneous input from the hand projects to SmI cortex in a single, complete, somatotopically organized pattern. Within this single pattern, cells with receptive fields on the glabrous skin of the palm, digits and digit tips are located in the rostral half, and cells with RFs on the hairy skin of the dorsal hand and digits are located in the caudal half of the hand areas. The cutaneous hand area is coextensive with the densely granular architectonic region of SmI. Studies of single cells in this region of awake galagos reveal the same pattern of cutaneous input and, in addition, demonstrate the presence of cells responding to joint movement not detected in anesthetized animals. Cells responsive to joint movement are arranged in vertically oriented columns located adjacent to cutaneous columns with receptive fields on the same part of the hand. In anesthetized animals, cells rostral to the granular region, in an area typified by increasing numbers of pyramidal cells in layer V and decreasing numbers of granular cells in upper layers, respond to high threshold stimulation of large areas of the hand. The few cells isolated in this area in awake animals respond to either active or passive hand movements. In such animals, cells caudal to the granular region, in an area characterized as agranular and alaminar cortex, respond to either passive stimulation of single or multiple joints or to active hand movements. These results, together with similar findings in a related prosimian, Nycticebus coucang, emphasize the generality of a single cutaneous hand area in SmI of prosimian species. The demonstration of multiple hand areas corresponding to multiple cytoarchitectonic subdivisions in SmI of Old and New World simians illustrates the increased degree of SmI differentiation from the prosimian to the simian grade of organization. The present results further suggest that determination of the homologues of multiple areas or subdivisions within and surrounding SmI in primates will require comparisons of somatotopy, submodality, sulcal patterns, cytoarchitecture, and connectivity in representative members of prosimian and simian families.

Granular computing with multiple granular layers for brain big data processing.

PubMed

Wang, Guoyin; Xu, Ji

2014-12-01

Big data is the term for a collection of datasets so huge and complex that it becomes difficult to be processed using on-hand theoretical models and technique tools. Brain big data is one of the most typical, important big data collected using powerful equipments of functional magnetic resonance imaging, multichannel electroencephalography, magnetoencephalography, Positron emission tomography, near infrared spectroscopic imaging, as well as other various devices. Granular computing with multiple granular layers, referred to as multi-granular computing (MGrC) for short hereafter, is an emerging computing paradigm of information processing, which simulates the multi-granular intelligent thinking model of human brain. It concerns the processing of complex information entities called information granules, which arise in the process of data abstraction and derivation of information and even knowledge from data. This paper analyzes three basic mechanisms of MGrC, namely granularity optimization, granularity conversion, and multi-granularity joint computation, and discusses the potential of introducing MGrC into intelligent processing of brain big data.

[Effect of electroacupuncture on cellular structure of hippocampus in splenic asthenia pedo-rats].

PubMed

Yang, Zhuo-xin; Zhuo, Yuan-yuan; Yu, Hai-bo; Wang, Ning

2010-02-01

To observe the effect of electroacupuncture (EA) on hippocampal structure in splenic asthenia pedo-rats. A total of 15 SD male rats were randomly assigned to normal control group (n=5), model group (n=5) and EA group (n=5). Splenic asthenic syndrome model was established by intragastric administration of rhubarb and intraperitoneal injection of Reserpine for 14 d. EA (1 mA, 3 Hz/iS Hz) was applied to bilateral "Zusanli" (ST 36) and "Sanyinjiao" (SP 6) for 20 mm, once a day for 14 days. The cellular structure of hippocampus was observed by light microscope and transmission electron microscope. Optical microscopic observation showed that in normal control group, the cellular nucleus was distinct, and the granular cell layer well-arranged and tight. In model group, the intracellular space was widened, and the granular cell layer was out of order in the arrangement. In EA group, the celluldr nucleus and the granular cell layer were nearly normal. Results of the electronic microscope showed that cells in model group had a karyopyknosis with irregular appearance and clear incisure, and some of them presented dissolving and necrotic phenomena; and those in EA group were milder in injury, had nearly-normal nucleus with visible nucleoli and relatively-intact nuclear membrane. Regarding the cellular plasma, in comparison with rich normal organelles of control group, the mitochondria in model group were swelling, with vague, dissolved and broken cristae, while in EA group, majority of the organelles were well-kept, and slightly dissolved mitochondrial cristae found. In regard to the synaptic structure, in comparison with control group, synaptic apomorphosis and swelling mitochondria were found in model group While in EA group, milder swelling and hydropic degeneration were seen. Different from the distinct pre- and post-synaptic membrane and synaptic vesicles of control group, while those in EA group were nearly-normal. electroacupunture can effectively relieve splenasthenic syndrome induced pathohistological changes of neurons of the hippocampus in the rat.

Notch Signaling Regulates Late-Stage Epidermal Differentiation and Maintains Postnatal Hair Cycle Homeostasis

PubMed Central

Lin, Hsien-Yi; Kao, Cheng-Heng; Lin, Kurt Ming-Chao; Kaartinen, Vesa; Yang, Liang-Tung

2011-01-01

Background Notch signaling involves ligand-receptor interactions through direct cell-cell contact. Multiple Notch receptors and ligands are expressed in the epidermis and hair follicles during embryonic development and the adult stage. Although Notch signaling plays an important role in regulating differentiation of the epidermis and hair follicles, it remains unclear how Notch signaling participates in late-stage epidermal differentiation and postnatal hair cycle homeostasis. Methodology and Principal Findings We applied Cre/loxP system to generate conditional gene targeted mice that allow inactivation of critical components of Notch signaling pathway in the skin. Rbpj, the core component of all four Notch receptors, and Pofut1, an essential factor for ligand-receptor interactions, were inactivated in hair follicle lineages and suprabasal layer of the epidermis using the Tgfb3-Cre mouse line. Rbpj conditional inactivation resulted in granular parakeratosis and reactive epidermal hyperplasia. Pofut1 conditional inactivation led to ultrastructural abnormalities in the granular layer and altered filaggrin processing in the epidermis, suggesting a perturbation of the granular layer differentiation. Disruption of Pofut1 in hair follicle lineages resulted in aberrant telogen morphology, a decrease of bulge stem cell markers, and a concomitant increase of K14-positive keratinocytes in the isthmus of mutant hair follicles. Pofut1-deficent hair follicles displayed a delay in anagen re-entry and dysregulation of proliferation and apoptosis during the hair cycle transition. Moreover, increased DNA double stand breaks were detected in Pofut1-deficent hair follicles, and real time PCR analyses on bulge keratinocytes isolated by FACS revealed an induction of DNA damage response and a paucity of DNA repair machinery in mutant bulge keratinocytes. Significance our data reveal a role for Notch signaling in regulating late-stage epidermal differentiation. Notch signaling is required for postnatal hair cycle homeostasis by maintaining proper proliferation and differentiation of hair follicle stem cells. PMID:21267458

Invited Article: Refractive index matched scanning of dense granular materials

NASA Astrophysics Data System (ADS)

Dijksman, Joshua A.; Rietz, Frank; Lőrincz, Kinga A.; van Hecke, Martin; Losert, Wolfgang

2012-01-01

We review an experimental method that allows to probe the time-dependent structure of fully three-dimensional densely packed granular materials and suspensions by means of particle recognition. The method relies on submersing a granular medium in a refractive index matched fluid. This makes the resulting suspension transparent. The granular medium is then visualized by exciting, layer by layer, the fluorescent dye in the fluid phase. We collect references and unreported experimental know-how to provide a solid background for future development of the technique, both for new and experienced users.

Distribution of caspase-14 in epidermis and hair follicles is evolutionarily conserved among mammals.

PubMed

Alibardi, Lorenzo; Tschachler, Erwin; Eckhart, Leopold

2005-10-01

Caspase-14, a member of the caspase family of cysteine proteases, is almost exclusively expressed in the epidermis. Studies on human and mouse cells and tissues have implicated caspase-14 in terminal differentiation of epidermal keratinocytes and in the formation of the stratum corneum. Here we investigated evolutionary aspects of the role of caspase-14 by analyzing its distribution in the epidermis and hair follicles of representative species of placental mammals, marsupials, and monotremes. Immunocytochemical staining showed that caspase-14 is consistently expressed in the granular and corneous layer of the epidermis of all mammalian species investigated. Ultrastructural analysis using gold-labeled anticaspase-14 antibodies revealed that caspase-14 is associated preferentially with keratin bundles and amorphous material of keratohyalin granules, but is also present in nuclei of transitional cells of the granular layer and in corneocytes. In hair follicles, caspase-14 was diffusely present in cornifying cells of the outer root sheath, in the companion layer, and, most abundantly, in the inner root sheath of all mammalian species here analyzed. In Henle and Huxley layers of the inner root sheath, labeling was seen in nuclei and, more diffusely, among trichohyalin granules of cornifying cells. In summary, the tissue expression pattern and the intracellular localization of caspase-14 are highly conserved among diverse mammalian species, suggesting that this enzyme is involved in a molecular process that appeared early in the evolution of mammalian skin. The association of caspase-14 with keratohyalin and trichohyalin granules may indicate a specific role of caspase-14 in the maturation of these keratinocyte-specific structures.

Chip-scale pattern modification method for equalizing residual layer thickness in nanoimprint lithography

NASA Astrophysics Data System (ADS)

Youn, Sung-Won; Suzuki, Kenta; Hiroshima, Hiroshi

2018-06-01

A software program for modifying a mold design to obtain a uniform residual layer thickness (RLT) distribution has been developed and its validity was verified by UV-nanoimprint lithography (UV-NIL) simulation. First, the effects of granularity (G) on both residual layer uniformity and filling characteristics were characterized. For a constant complementary pattern depth and a granularity that was sufficiently larger than the minimum pattern width, filling time decreased with the decrease in granularity. For a pattern design with a wide density range and an irregular distribution, the choice of a small granularity was not always a good strategy since the etching depth required for a complementary pattern occasionally exceptionally increased with the decrease in granularity. On basis of the results obtained, the automated method was applied to a chip-scale pattern modification. Simulation results showed a marked improvement in residual layer thickness uniformity for a capacity-equalized (CE) mold. For the given conditions, the standard deviation of RLT decreased in the range from 1/3 to 1/5 in accordance with pattern designs.

Computational Architecture of the Granular Layer of Cerebellum-Like Structures.

PubMed

Bratby, Peter; Sneyd, James; Montgomery, John

2017-02-01

In the adaptive filter model of the cerebellum, the granular layer performs a recoding which expands incoming mossy fibre signals into a temporally diverse set of basis signals. The underlying neural mechanism is not well understood, although various mechanisms have been proposed, including delay lines, spectral timing and echo state networks. Here, we develop a computational simulation based on a network of leaky integrator neurons, and an adaptive filter performance measure, which allows candidate mechanisms to be compared. We demonstrate that increasing the circuit complexity improves adaptive filter performance, and relate this to evolutionary innovations in the cerebellum and cerebellum-like structures in sharks and electric fish. We show how recurrence enables an increase in basis signal duration, which suggest a possible explanation for the explosion in granule cell numbers in the mammalian cerebellum.

Acral peeling skin syndrome: report of two cases.

PubMed

García, Elena García; Carreño, Rosario Granados; Martínez González, Miguel A; Reyes, José Jiménez

2005-01-01

Peeling skin syndrome is a rare dermatosis characterized by spontaneous and painless peeling of the skin. The authors report two patients with history of spontaneous, asymptomatic, and noninflammatory peeling skin of the acral surfaces after soaking in water. On light microscopy, blisters were located in the mid layers of the stratum corneum, above the granular layer. Ultrastructural examination revealed increased intercellular lipids and abnormal, "moth-eaten," keratohyalin granules, but the authors were unable to determine whether the separation initiated within the horny cells or between adjacent cells. These patients represented a localized variant of peeling skin syndrome.

Protease-Activated Receptor-2 Is Associated with Terminal Differentiation of Epidermis and Eccrine Sweat Glands

PubMed Central

Shin, Yong-Sup; Kim, Hyung Won; Kim, Chang Deok; Kim, Hyun-Woo; Park, Jin Woon; Jung, Sunggyun; Lee, Jeung-Hoon; Ko, Young-Kwon

2015-01-01

Background Protease-activated receptor 2 (PAR-2) participates in various biological activities, including the regulation of epidermal barrier homeostasis, inflammation, pain perception, and melanosome transfer in the skin. Objective To evaluate the basic physiological role of PAR-2 in skin. Methods We investigated PAR-2 expression in human epidermis, skin tumors, and cultured epidermal cells using western blot and immunohistochemical analysis. Additionally, we examined the effect of the PAR-2 agonist, SLIGRL-NH2, on cultured keratinocytes. Results Strong PAR-2 immunoreactivity was observed in the granular layer of normal human skin and the acrosyringium of the eccrine sweat glands. In contrast, weak PAR-2 immunoreactivity was seen in the granular layer of callused skin and in the duct and gland cells of the eccrine sweat glands. Interestingly, PAR-2 immunoreactivity was very weak or absent in the tumor cells of squamous cell carcinoma (SCC) and syringoma. PAR-2 was detected in primary keratinocytes and SV-40T-transformed human epidermal keratinocytes (SV-HEKs), an immortalized keratinocyte cell line, but not in SCC12 cells. SV-HEKs that were fully differentiated following calcium treatment displayed higher PAR-2 expression than undifferentiated SV-HEKs. Treatment of cultured SV-HEKs with PAR-2 agonist increased loricrin and filaggrin expression, a terminal differentiation marker. Conclusion Our data suggest that PAR-2 is associated with terminal differentiation of epidermis and eccrine sweat glands. PMID:26273149

Protease-Activated Receptor-2 Is Associated with Terminal Differentiation of Epidermis and Eccrine Sweat Glands.

PubMed

Shin, Yong-Sup; Kim, Hyung Won; Kim, Chang Deok; Kim, Hyun-Woo; Park, Jin Woon; Jung, Sunggyun; Lee, Jeung-Hoon; Ko, Young-Kwon; Lee, Young Ho

2015-08-01

Protease-activated receptor 2 (PAR-2) participates in various biological activities, including the regulation of epidermal barrier homeostasis, inflammation, pain perception, and melanosome transfer in the skin. To evaluate the basic physiological role of PAR-2 in skin. We investigated PAR-2 expression in human epidermis, skin tumors, and cultured epidermal cells using western blot and immunohistochemical analysis. Additionally, we examined the effect of the PAR-2 agonist, SLIGRL-NH2, on cultured keratinocytes. Strong PAR-2 immunoreactivity was observed in the granular layer of normal human skin and the acrosyringium of the eccrine sweat glands. In contrast, weak PAR-2 immunoreactivity was seen in the granular layer of callused skin and in the duct and gland cells of the eccrine sweat glands. Interestingly, PAR-2 immunoreactivity was very weak or absent in the tumor cells of squamous cell carcinoma (SCC) and syringoma. PAR-2 was detected in primary keratinocytes and SV-40T-transformed human epidermal keratinocytes (SV-HEKs), an immortalized keratinocyte cell line, but not in SCC12 cells. SV-HEKs that were fully differentiated following calcium treatment displayed higher PAR-2 expression than undifferentiated SV-HEKs. Treatment of cultured SV-HEKs with PAR-2 agonist increased loricrin and filaggrin expression, a terminal differentiation marker. Our data suggest that PAR-2 is associated with terminal differentiation of epidermis and eccrine sweat glands.

Effects of Ascorbyl-2-phosphate Magnesium on Human Keratinocyte Toxicity and Pathological Changes by Sorafenib.

PubMed

Yamamoto, Kazuhiro; Shichiri, Hiroaki; Ishida, Takahiro; Kaku, Kenta; Nishioka, Tatsuya; Kume, Manabu; Makimoto, Hiroo; Nakagawa, Tsutomu; Hirano, Takeshi; Bito, Toshinori; Nishigori, Chikako; Yano, Ikuko; Hirai, Midori

2017-01-01

Hand-foot skin reaction is recognized as one of the most common adverse events related to multiple tyrosine kinase inhibitors, but an effective prevention method has not been identified. The chief aim of this study was to find a mechanism-based preventive method for the skin toxicity induced by sorafenib using vitamin C derivatives. The effects of ascorbyl-2-phosphate magnesium (P-VC-Mg) on the molecular and pathological changes induced by sorafenib were investigated in human keratinocyte HaCaT cells. The cell growth inhibition and apoptotic effects of sorafenib were attenuated by P-VC-Mg. Moreover, P-VC-Mg inhibited the decrease of signal transducer and activator of transcription 3 (STAT3) phosphorylation and the expression of apoptosis suppressors treated by sorafenib. HaCaT cells transfected with the STAT3 dominant-negative form (STAT3DN) and STAT3 small interfering RNA (siRNA) combined with P-VC-Mg did not exhibit the attenuation of cell growth inhibition. Interestingly, after exposure to sorafenib in a three dimensional (3D) skin model assay, the basal layer was significantly thickened and the granular and spinous layers became thinner. In contrast, after exposure to sorafenib with P-VC-Mg, the thickness of the basal, granular, and spinous layers was similar to that of the control image. These findings suggest that P-VC-Mg attenuates sorafenib-induced apoptosis and pathological changes in human keratinocyte cells and in the 3D skin model mediated by the maintenance of STAT3 activity.

Highly (002) textured large grain bcc Cr{sub 80}Mn{sub 20} seed layer on Cr{sub 50}Ti{sub 50} amorphous layer for FePt-C granular film

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jeon, Seong-Jae, E-mail: jsjigst@ecei.tohoku.ac.jp; Saito, Shin; Hinata, Shintaro

Effect of bcc Cr{sub 80}Mn{sub 20} seed layer and Cr{sub 50}Ti{sub 50} amorphous texture inducing layer on the heteroepitaxy system in FePt-C granular film was studied by introducing a new concept of the layered structure. The concept suggested that the large grain seed layer in which the crystallographic texture was initially formed on an amorphous layer in the layered structure can reduce the angular distribution of (002) c-axis crystal orientation in the FePt-C granular film owing to heteroepitaxial growth. Structure analysis by X-ray diffraction revealed that (1) when the substrate heating temperature was elevated from 300 °C to 500 °C, grain sizemore » in the seed layer increased from 9.8 nm to 11.6 nm, and then decreased with further increasing the substrate temperature. The reduction of the grain size over 500 °C corresponds to the crystallization of the amorphous texture inducing layer, (2) when the grain size increased from 9.8 nm to 11.6 nm, the angular distribution of the (002) orientation in the seed layer dramatically decreased from 13.7° to 4.1°. It was shown that the large grain seed layer increased the perpendicular hysteresis in FePt-C granular film.« less

Two-Phase Solid/Fluid Simulation of Dense Granular Flows With Dilatancy Effects

NASA Astrophysics Data System (ADS)

Mangeney, Anne; Bouchut, Francois; Fernandez-Nieto, Enrique; Narbona-Reina, Gladys; Kone, El Hadj

2017-04-01

Describing grain/fluid interaction in debris flows models is still an open and challenging issue with key impact on hazard assessment [1]. We present here a two-phase two-thin-layer model for fluidized debris flows that takes into account dilatancy effects. It describes the velocity of both the solid and the fluid phases, the compression/ dilatation of the granular media and its interaction with the pore fluid pressure [2]. The model is derived from a 3D two-phase model proposed by Jackson [3] and the mixture equations are closed by a weak compressibility relation. This relation implies that the occurrence of dilation or contraction of the granular material in the model depends on whether the solid volume fraction is respectively higher or lower than a critical value. When dilation occurs, the fluid is sucked into the granular material, the pore pressure decreases and the friction force on the granular phase increases. On the contrary, in the case of contraction, the fluid is expelled from the mixture, the pore pressure increases and the friction force diminishes. To account for this transfer of fluid into and out of the mixture, a two-layer model is proposed with a fluid or a solid layer on top of the two-phase mixture layer. Mass and momentum conservation are satisfied for the two phases, and mass and momentum are transferred between the two layers. A thin-layer approximation is used to derive average equations. Special attention is paid to the drag friction terms that are responsible for the transfer of momentum between the two phases and for the appearance of an excess pore pressure with respect to the hydrostatic pressure. Interestingly, when removing the role of water, our model reduces to a dry granular flow model including dilatancy. We first compare experimental and numerical results of dilatant dry granular flows. Then, by quantitatively comparing the results of simulation and laboratory experiments on submerged granular flows, we show that our model contains the basic ingredients making it possible to reproduce the interaction between the granular and fluid phases through the change in pore fluid pressure. In particular, we analyse the different time scales in the model and their role in granular/fluid flow dynamics. References [1] R. Delannay, A. Valance, A. Mangeney, O. Roche, P. Richard, J. Phys. D: Appl. Phys., in press (2016). [2] F. Bouchut, E. D. Fernández-Nieto, A. Mangeney, G. Narbona-Reina, J. Fluid Mech., 801, 166-221 (2016). [3] R. Jackson, Cambridges Monographs on Mechanics (2000).

Structural and ultrastructural features of the agouti tongue (Dasyprocta aguti Linnaeus, 1766)

PubMed Central

Ciena, Adriano Polican; Bolina, Cristina de Sousa; de Almeida, Sonia Regina Yokomizo; Rici, Rose Eli Grassi; de Oliveira, Moacir Franco; da da Silva, Marcelo Cavenaghi Pereira; Miglino, Maria Angélica; Watanabe, Ii-sei

2013-01-01

The agouti (Dasyprocta aguti Linnaeus, 1766) is a wild rodent belonging to the family Dasyproctidae that is found throughout Brazil and feeds on fruits and seeds. The aim of the present study was to describe the following features of the tongue of agouti: its morphological structures, the three-dimensional characteristics of the lingual papillae surface, the connective tissue cores (CTCs) and the epithelial cell ultrastructure. Four types of papillae were observed on the dorsal surface of the tongue with a triangular shape: filiform, fungiform, foliate and vallate. Filiform papillae were distributed throughout the tongue surface, and removal of the epithelial surface revealed conical CTCs and multifilaments. Fungiform papillae were observed in the rostral and middle regions, whereas foliate papillae developed in pairs on the lateral margin of the caudal region. Removal of the epithelium in these regions revealed CTCs with parallel laminar conformation. Vallate papillae were arranged in a V-shape in the caudal region, and their CTCs ranged in shape from elongate to ovoid. The ultrastructural components of the dorsal epithelium were the basal, spinous, granular and keratinised layers. A broad area with cytoplasmic projections was identified in the interface region between the lamina propria and the basal layer. Flattened cells with intermediate filaments were observed in the transitional region between spinous and granular layers. The keratinised layer was composed of superimposed epithelial cells where desmosomes and cell-surface microridges were observed. These structural features, including the three-dimensional aspects of the lingual papillae, the CTCs and the epithelial ultrastructure, indicate that when compared with other animals, particularly other rodent species, the morphological features of the tongue of agouti are relatively well developed, especially regarding foliate and vallate papillae. PMID:23701183

Rapid granular flows on a rough incline: phase diagram, gas transition, and effects of air drag.

PubMed

Börzsönyi, Tamás; Ecke, Robert E

2006-12-01

We report experiments on the overall phase diagram of granular flows on an incline with emphasis on high inclination angles where the mean layer velocity approaches the terminal velocity of a single particle free falling in air. The granular flow was characterized by measurements of the surface velocity, the average layer height, and the mean density of the layer as functions of the hopper opening, the plane inclination angle, and the downstream distance x of the flow. At high inclination angles the flow does not reach an x -invariant steady state over the length of the inclined plane. For low volume flow rates, a transition was detected between dense and very dilute (gas) flow regimes. We show using a vacuum flow channel that air did not qualitatively change the phase diagram and did not quantitatively modify mean flow velocities of the granular layer except for small changes in the very dilute gaslike phase.

Grain scale observations of stick-slip dynamics in fluid saturated granular fault gouge

NASA Astrophysics Data System (ADS)

Johnson, P. A.; Dorostkar, O.; Guyer, R. A.; Marone, C.; Carmeliet, J.

2017-12-01

We are studying granular mechanics during slip. In the present work, we conduct coupled computational fluid dynamics (CFD) and discrete element method (DEM) simulations to study grain scale characteristics of slip instabilities in fluid saturated granular fault gouge. The granular sample is confined with constant normal load (10 MPa), and sheared with constant velocity (0.6 mm/s). This loading configuration is chosen to promote stick-slip dynamics, based on a phase-space study. Fluid is introduced in the beginning of stick phase and characteristics of slip events i.e. macroscopic friction coefficient, kinetic energy and layer thickness are monitored. At the grain scale, we monitor particle coordination number, fluid-particle interaction forces as well as particle and fluid kinetic energy. Our observations show that presence of fluids in a drained granular fault gouge stabilizes the layer in the stick phase and increases the recurrence time. In saturated model, we observe that average particle coordination number reaches higher values compared to dry granular gouge. Upon slip, we observe that a larger portion of the granular sample is mobilized in saturated gouge compared to dry system. We also observe that regions with high particle kinetic energy are correlated with zones of high fluid motion. Our observations highlight that spatiotemporal profile of fluid dynamic pressure affects the characteristics of slip instabilities, increasing macroscopic friction coefficient drop, kinetic energy release and granular layer compaction. We show that numerical simulations help characterize the micromechanics of fault mechanics.

Species and distribution of inorganic and organic phosphorus in enhanced phosphorus removal aerobic granular sludge.

PubMed

Huang, Wenli; Huang, Weiwei; Li, Huifang; Lei, Zhongfang; Zhang, Zhenya; Tay, Joo Hwa; Lee, Duu-Jong

2015-10-01

The species and distribution of phosphorus (P) in an enhanced biological phosphorus removal (EBPR)-aerobic granular sludge (AGS) were fractionated and further analyzed. Results showed that microbial cells, extracellular polymeric substances (EPS) and mineral precipitates contributed about 73.7%, 17.6% and 5.3-6.4% to the total P (TP) of EBPR-AGS, respectively. Inorganic P (IP) species were orthophosphate, pyrophosphate and polyphosphate among which polyphosphate was the major P species in the AGS, cells and EPS. Monoester and diester phosphates were identified as the organic P (OP) species in the AGS and cells. Hydroxyapatite (Ca5(PO4)3OH) and calcium phosphate (Ca2(PO4)3) were the dominant P minerals accumulated in the core of the granules. Cells along with polyphosphate were mainly in the outer layer of AGS while EPS were distributed in the whole granules. Based on the above results, the distribution of IP and OP species in AGS has been conceived. Copyright © 2015 Elsevier Ltd. All rights reserved.

"EGM" (Electrostatics of Granular Matter): A Space Station Experiment to Examine Natural Particulate Systems

NASA Astrophysics Data System (ADS)

Marshall, J.; Sauke, T.; Buehler, M.; Farrell, W.; Green, R.; Birchenough, A.

1999-09-01

A granular-materials experiment is being developed for a 2002 launch for Space Station deployment. The experiment is funded by NASA HQ and managed through NASA Lewis Research Center. The experiment will examine electrostatic aggregation of coarse granular materials with the goals of (a) obtaining proof for an electrostatic dipole model of grain interactions, and (b) obtaining knowledge about the way aggregation affects the behavior of natural particulate masses: (1) in unconfined dispersions (clouds such as nebulae, aeolian dust palls, volcanic plumes), (2) in semi-confined, self-loaded masses as in fluidized flows (pyroclastic surges, avalanches) and compacted regolith, or (3) in semi-confined non-loaded masses as in dust layers adhering to solar cells or space suits on Mars. The experiment addresses both planetary/astrophysical issues as well as practical concerns for human exploration of Mars or other solar system bodies. Additional information is contained in the original.

Histology and ultrastructure of the coenenchyme of the octocoral Swiftia exserta, a model organism for innate immunity/graft rejection.

PubMed

Menzel, L P; Tondo, C; Stein, B; Bigger, C H

2015-04-01

The octocoral Swiftia exserta has been utilized extensively in our laboratory to study innate immune reactions in Cnidaria such as wound healing, auto- and allo-graft reactions, and for some classical "foreign body" phagocytosis experiments. All of these reactions occur in the coenenchyme of the animal, the colonial tissue surrounding the axial skeleton in which the polyps are embedded, and do not rely on nematocysts or directly involve the polyps. In order to better understand some of the cellular reactions occurring in the coenenchyme, the present study employed several cytochemical methods (periodic acid-Schiff reaction, Mallory's aniline blue collagen stain, and Gomori's trichrome stain) and correlated the observed structures with electron microscopy (both scanning and transmission). Eight types of cells were apparent in the coenenchyme of S. exserta, exclusive of gastrodermal tissue: (i) epithelial ectoderm cells, (ii) oblong granular cells, (iii) granular amoebocytes, (iv) morula-like cells, (v) mesogleal cells, (vi) sclerocytes, (vii) axial epithelial cells, and (viii) cnidocytes with mostly atrichous isorhiza nematocysts. Several novel organizational features are now apparent from transmission electron micrographs: the ectoderm consists of a single layer of flat epithelial cells, the cell types of the mesoglea extend from beneath the thin ectoderm throughout the mesogleal cell cords, the organization of the solenia gastroderm consists of a single layer of cells, and two nematocyst types have been found. A new interpretation of the cellular architecture of S. exserta, and more broadly, octocoral biology is now possible. Copyright © 2014 Elsevier GmbH. All rights reserved.

Histology and ultrastructure of the coenenchyme of the octocoral Swiftia exserta, a model organism for innate immunity/graft rejection

PubMed Central

Menzel, L.P.; Tondo, C.; Stein, B.; Bigger, C.H.

2015-01-01

The octocoral Swiftia exserta has been utilized extensively in our laboratory to study innate immune reactions in Cnidaria such as wound healing, auto- and allo-graft reactions, and for some classical “foreign body” phagocytosis experiments. All of these reactions occur in the coenenchyme of the animal, the colonial tissue surrounding the axial skeleton in which the polyps are embedded, and do not rely on nematocysts or directly involve the polyps. In order to better understand some of the cellular reactions occurring in the coenenchyme, the present study employed several cytochemical methods (periodic acid–Schiff reaction, Mallory’s aniline blue collagen stain, and Gomori’s trichrome stain) and correlated the observed structures with electron microscopy (both scanning and transmission). Eight types of cells were apparent in the coenenchyme of S. exserta, exclusive of gastrodermal tissue: (i) epithelial ectoderm cells, (ii) oblong granular cells, (iii) granular amoebocytes, (iv) morula-like cells, (v) mesogleal cells, (vi) sclerocytes, (vii) axial epithelial cells, and (viii) cnidocytes with mostly atrichous isorhiza nematocysts. Several novel organizational features are now apparent from transmission electron micrographs: the ectoderm consists of a single layer of flat epithelial cells, the cell types of the mesoglea extend from beneath the thin ectoderm throughout the mesogleal cell cords, the organization of the solenia gastroderm consists of a single layer of cells, and two nematocyst types have been found. A new interpretation of the cellular architecture of S. exserta, and more broadly, octocoral biology is now possible. PMID:25596959

Nonlinear instability and convection in a vertically vibrated granular bed

NASA Astrophysics Data System (ADS)

Shukla, Priyanka; Ansari, I. H.; van der Meer, D.; Lohse, Detlef; Alam, Meheboob

2015-11-01

The nonlinear instability of the density-inverted granular Leidenfrost state and the resulting convective motion in strongly shaken granular matter are analysed via a weakly nonlinear analysis. Under a quasi-steady ansatz, the base state temperature decreases with increasing height away from from the vibrating plate, but the density profile consists of three distinct regions: (i) a collisional dilute layer at the bottom, (ii) a levitated dense layer at some intermediate height and (iii) a ballistic dilute layer at the top of the granular bed. For the nonlinear stability analysis, the nonlinearities up-to cubic order in perturbation amplitude are retained, leading to the Landau equation. The genesis of granular convection is shown to be tied to a supercritical pitchfork bifurcation from the Leidenfrost state. Near the bifurcation point the equilibrium amplitude is found to follow a square-root scaling law, Ae √{ ▵} , with the distance ▵ from bifurcation point. The strength of convection is maximal at some intermediate value of the shaking strength, with weaker convection both at weaker and stronger shaking. Our theory predicts a novel floating-convection state at very strong shaking.

Cytogenetic and molecular genetic study on granular cell glioblastoma: a case report.

PubMed

Joo, Mee; Park, Sung-Hye; Chang, Sun Hee; Kim, Hanseong; Choi, Chan-Young; Lee, Chae-Heuck; Lee, Byung Hoon; Hwang, Yoon Joon

2013-02-01

Granular cell astrocytoma is a rare infiltrative malignant glioma with prominent granular cell change. Granular cell astrocytomas are biologically aggressive compared with conventional infiltrating astrocytomas of similar grades, but their genetic alterations are poorly known. We report a case of granular cell glioblastoma and its genetic and molecular features. Histologically, the tumor not only showed features typical of granular cell astrocytoma but also demonstrated frequent mitoses, pseudopalisading necrosis, and vascular endothelial hyperplasia, compatible with glioblastoma. Array-based comparative genomic hybridization and focused molecular genetic analyses demonstrated gain of chromosome 7; losses of chromosome 1p, 8p, 9p, 10, 13q, and 22q; amplification of epidermal growth factor receptor; and homozygous deletion of CDKN2A as well as MGMT promoter methylation. However, neither isocitrate dehydrogenase 1 mutation nor codeletion of 1p/19q was found. Our results indicate that granular cell glioblastomas, despite having its peculiar granular cell changes, share common molecular genetic features with conventional glioblastoma, especially the classical subtype. Copyright © 2013 Elsevier Inc. All rights reserved.

Acoustically induced slip in sheared granular layers: Application to dynamic earthquake triggering: TRIGGERED SLIP IN SHEARED GRANULAR GOUGE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ferdowsi, Behrooz; Griffa, Michele; Guyer, Robert A.

A fundamental mystery in earthquake physics is “how can an earthquake be triggered by distant seismic sources?” We use discrete element method simulations of a granular layer, during stick slip, that is subject to transient vibrational excitation to gain further insight into the physics of dynamic earthquake triggering. We also observe delayed triggering of slip in the granular gouge, using Coulomb friction law for grains interaction. We find that at a critical vibrational amplitude (strain) there is an abrupt transition from negligible time-advanced slip (clock advance) to full clock advance; i.e., transient vibration and triggered slip are simultaneous. Moreover, themore » critical strain is of order 10 -6, similar to observations in the laboratory and in Earth. The transition is related to frictional weakening of the granular layer due to a dramatic decrease in coordination number and the weakening of the contact force network. Associated with this frictional weakening is a pronounced decrease in the elastic modulus of the layer. The study has important implications for mechanisms of triggered earthquakes and induced seismic events and points out the underlying processes in response of the fault gouge to dynamic transient stresses.« less

Acoustically induced slip in sheared granular layers: Application to dynamic earthquake triggering: TRIGGERED SLIP IN SHEARED GRANULAR GOUGE

DOE PAGES

Ferdowsi, Behrooz; Griffa, Michele; Guyer, Robert A.; ...

2015-11-19

A fundamental mystery in earthquake physics is “how can an earthquake be triggered by distant seismic sources?” We use discrete element method simulations of a granular layer, during stick slip, that is subject to transient vibrational excitation to gain further insight into the physics of dynamic earthquake triggering. We also observe delayed triggering of slip in the granular gouge, using Coulomb friction law for grains interaction. We find that at a critical vibrational amplitude (strain) there is an abrupt transition from negligible time-advanced slip (clock advance) to full clock advance; i.e., transient vibration and triggered slip are simultaneous. Moreover, themore » critical strain is of order 10 -6, similar to observations in the laboratory and in Earth. The transition is related to frictional weakening of the granular layer due to a dramatic decrease in coordination number and the weakening of the contact force network. Associated with this frictional weakening is a pronounced decrease in the elastic modulus of the layer. The study has important implications for mechanisms of triggered earthquakes and induced seismic events and points out the underlying processes in response of the fault gouge to dynamic transient stresses.« less

Granular Contact Forces: Proof of "Self-Ergodicity" by Generalizing Boltzmann's Stosszahlansatz and H Theorem

NASA Technical Reports Server (NTRS)

Metzger, Philip T.

2006-01-01

Ergodicity is proved for granular contact forces. To obtain this proof from first principles, this paper generalizes Boltzmann's stosszahlansatz (molecular chaos) so that it maintains the necessary correlations and symmetries of granular packing ensembles. Then it formally counts granular contact force states and thereby defines the proper analog of Boltzmann's H functional. This functional is used to prove that (essentially) all static granular packings must exist at maximum entropy with respect to their contact forces. Therefore, the propagation of granular contact forces through a packing is a truly ergodic process in the Boltzmannian sense, or better, it is self-ergodic. Self-ergodicity refers to the non-dynamic, internal relationships that exist between the layer-by-layer and column-by-column subspaces contained within the phase space locus of any particular granular packing microstate. The generalized H Theorem also produces a recursion equation that may be solved numerically to obtain the density of single particle states and hence the distribution of granular contact forces corresponding to the condition of self-ergodicity. The predictions of the theory are overwhelmingly validated by comparison to empirical data from discrete element modeling.

Two-Phase Solid/Fluid Simulation of Dense Granular Flows With Dilatancy Effects

NASA Astrophysics Data System (ADS)

Mangeney, A.; Bouchut, F.; Fernández-Nieto, E. D.; Kone, E. H.; Narbona-Reina, G.

2016-12-01

Describing grain/fluid interaction in debris flows models is still an open and challenging issue with key impact on hazard assessment [1]. We present here a two-phase two-thin-layer model for fluidized debris flows that takes into account dilatancy effects. It describes the velocity of both the solid and the fluid phases, the compression/ dilatation of the granular media and its interaction with the pore fluid pressure [2]. The model is derived from a 3D two-phase model proposed by Jackson [3] and the mixture equations are closed by a weak compressibility relation. This relation implies that the occurrence of dilation or contraction of the granular material in the model depends on whether the solid volume fraction is respectively higher or lower than a critical value. When dilation occurs, the fluid is sucked into the granular material, the pore pressure decreases and the friction force on the granular phase increases. On the contrary, in the case of contraction, the fluid is expelled from the mixture, the pore pressure increases and the friction force diminishes. To account for this transfer of fluid into and out of the mixture, a two-layer model is proposed with a fluid or a solid layer on top of the two-phase mixture layer. Mass and momentum conservation are satisfied for the two phases, and mass and momentum are transferred between the two layers. A thin-layer approximation is used to derive average equations. Special attention is paid to the drag friction terms that are responsible for the transfer of momentum between the two phases and for the appearance of an excess pore pressure with respect to the hydrostatic pressure. By comparing quantitatively the results of simulation and laboratory experiments on submerged granular flows, we show that our model contains the basic ingredients making it possible to reproduce the interaction between the granular and fluid phases through the change in pore fluid pressure. In particular, we analyse the different time scales in the model and their role in granular/fluid flow dynamics. References[1] R. Delannay, A. Valance, A. Mangeney, O. Roche, P. Richard, J. Phys. D: Appl. Phys., in press (2016). [2] F. Bouchut, E. D. Fernández-Nieto, A. Mangeney, G. Narbona-Reina, J. Fluid Mech., 801, 166-221 (2016). [3] R. Jackson, Cambridges Monographs on Mechanics (2000).

Pore-scale Modeling of CO2 Local Trapping in Heterogeneous Porous Media with Inter-granular Cements

NASA Astrophysics Data System (ADS)

Wang, D.; Li, Y.

2017-12-01

Based on pore-scale modeling of CO2/brine multiphase flow in heterogeneous porous media with inter-granular cements, we numerically analyze the effects of cement-modified pore structure on CO2 local trapping. Results indicate: 1) small pore throat is the main reason for causing CO2 local trapping in front of low-porosity layers (namely dense layers) formed by inter-granular cements; 2) in the case of the same pore throat size, the smaller particle size can increase the number of flow paths for CO2 plume and equivalently enhances local permeability, which may counteract the impediment of high capillary pressure on CO2 migration to some extent and consequently disables CO2 local capillary trapping; 3) the isolated pores by inter-granular cements can lead to dramatic reduction of CO2 saturation inside the dense layers, whereas the change of connectivity of some pores due to the cements can increase CO2 accumulation in front of the dense layers by lowering the displacement area of CO2 plume.

Coupled granular/continuous medium for thermally stable perpendicular magnetic recording

NASA Astrophysics Data System (ADS)

Sonobe, Y.; Weller, D.; Ikeda, Y.; Takano, K.; Schabes, M. E.; Zeltzer, G.; Do, H.; Yen, B. K.; Best, M. E.

2001-10-01

We studied coupled granular/continuous (CGC) perpendicular media consisting of a continuous multilayer structure and a granular layer. The addition of Co/Pt multilayers decreased the nucleation field from 200 to -1800 Oe and increased the squareness from 0.9 to 1.0. The moment decay at room temperature was significantly reduced from -4.8% to -0.05% per decade. At elevated temperatures, strong exchange coupling between a granular layer and a continuous layer is needed for thermal stability. The exchange-coupled continuous layer reduces thermal demagnetization as it effectively increases the grain size, tightens the grain distribution, and prevents the reversal of individual grains. Magnetic Force Microscope image showed a larger magnetic cluster size for the CGC structure. Compared to the CoCr 18Pt 12 medium, the CGC medium had 2.3 dB higher output. However, the noise for the CGC medium increased with the recording density, while the noise for the CoCr 18Pt 12 medium remained constant from 4 to 15 kfc/mm. Further optimization and noise reduction are still required for future high density recording.

[Ultrastructural changes in cells of the inner enamel epithelium, stratum intermedium and reticulum stellatum in the enamel organ of the upper incisor of the Wistar rat at different phases of amelogenesis].

PubMed

Costacurta, L; de Carvalho, C A; König, B; Bilotta, J A

1976-01-01

An electronmicroscopical study of the enamel organ of the upper incisors germs of Wistar rats was performed to analyse the ultrastructural features of the cells of the inner epithelium, the intermediate layer and the stellate reticulum, during preimary, young, transitional and mineralized enamel phases of amelogenesis. So, it was observed that the mitochondria in the ameloblasts are ovoid before the beginning of the enamel matrix formation and in the primary and young enamel phases. However, in the transitional and mineralized phases, these organelles are long and tortuous and some are characterized by a compact structure. In the cells of intermediate layer and stellate reticulum, the mitochondria are ovoid until the beginning of the mineralized phase. At the ending of this phase, these organelles are very long and present irregular form; many of them show also a compact structure. The "zonula adhaerens" could be observed only in the ameloblasts of the primary and young enamel phase. The cytoplasm of ameloblasts, during primary and young enamel phases is characterized by an abundance of free ribosomes and a branular endoplasmic reticulum; but during transitional and mineralized enamel phases, the cytoplasm of these cells shows little granular endoplasmic reticulum and free ribosomes, but ehe agranular endoplasmic reticulum is present. The granular endoplasmic reticulum and free ribosomes are abundant in the cells of the intermediate layer and stellate reticulum at the ending of the young enamel phase, in the transitional enamel phase and in the beginning of the minieralized phase. During different phases of amelogenesis, in the three above referred layers of the enamel organ, were also studied the features of the Golgi apparatus the presence and topographic distribution of the pigment granules, as well as the lysosomes, desmosomes and the tonophibriles.

Spontaneous Emergence of Order in Vibrated Sand*

NASA Astrophysics Data System (ADS)

Swinney, Harry L.

2004-05-01

Granular media such as sand, pharmaceuticals, cereal, cosmetics, and asteroids are involved in many processes, yet granular media remain less well understood than fluids and solids. Vertically oscillating granular layers provide a test bed for theory and modeling of granular dynamics. Experiments on vertically oscillating granular layers have revealed a variety of spatial patterns that emerge spontaneously as a function of the container acceleration amplitude and frequency: stripes, squares, hexagons, spirals, and oscillons (localized structures). Molecular dynamics simulations yield results in quantitative accord with laboratory observations. Since the gradients of density and velocity are large over a particle mean free path, the applicability of continuum theory has been questionable. However, hydrodynamic equations proposed for dissipative particles yield results in surprising qualitative accord with the laboratory observations. *Work in collaboration with C. Bizon, D. Goldman, W.D. McCormick, S.J. Moon, E. Rericha, M. Shattuck, and J. Swift. Supported by DOE.

The Smo/Smo model: hedgehog-induced medulloblastoma with 90% incidence and leptomeningeal spread.

PubMed

Hatton, Beryl A; Villavicencio, Elisabeth H; Tsuchiya, Karen D; Pritchard, Joel I; Ditzler, Sally; Pullar, Barbara; Hansen, Stacey; Knoblaugh, Sue E; Lee, Donghoon; Eberhart, Charles G; Hallahan, Andrew R; Olson, James M

2008-03-15

Toward the goal of generating a mouse medulloblastoma model with increased tumor incidence, we developed a homozygous version of our ND2:SmoA1 model. Medulloblastomas form in 94% of homozygous Smo/Smo mice by 2 months of age. Tumor formation is, thus, predictable by age, before the symptomatic appearance of larger lesions. This high incidence and early onset of tumors is ideal for preclinical studies because mice can be enrolled before symptom onset and with a greater latency period before late-stage disease. Smo/Smo tumors also display leptomeningeal dissemination of neoplastic cells to the brain and spine, which occurs in many human cases. Despite an extended proliferation of granule neuron precursors (GNP) in the postnatal external granular layer (EGL), the internal granular layer formed normally in Smo/Smo mice and tumor formation occurred only in localized foci on the superficial surface of the molecular layer. Thus, tumor formation is not simply the result of over proliferation of GNPs within the EGL. Moreover, Smo/Smo medulloblastomas were transplantable and serially passaged in vivo, demonstrating the aggressiveness of tumor cells and their transformation beyond a hyperplastic state. The Smo/Smo model is the first mouse medulloblastoma model to show leptomeningeal spread. The adherence to human pathology, high incidence, and early onset of tumors thus make Smo/Smo mice an efficient model for preclinical studies.

Cerebellar abiotrophy in a family of Border Collie dogs.

PubMed

Sandy, J R; Slocombe, R E; Mitten, R W; Jedwab, D

2002-11-01

Cerebellar abiotrophies have a nonsex-linked, autosomal, recessively inherited basis in a number of species, and lesions typically reflect profound and progressive loss of Purkinje cells. In this report, an unusual form of abiotrophy is described for two sibling Border Collies. Extensive loss of the cerebellar granular cell layer was present with relative sparing of Purkinje cells of two female pups. The biochemical basis for this form of cerebellar abiotrophy is unknown, but the lack of disease in other siblings supports an autosomal recessive mode of inheritance.

Modeling of Stick-Slip Behavior in Sheared Granular Fault Gouge Using the Combined Finite-Discrete Element Method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gao, Ke; Euser, Bryan J.; Rougier, Esteban

Sheared granular layers undergoing stick-slip behavior are broadly employed to study the physics and dynamics of earthquakes. In this paper, a two-dimensional implementation of the combined finite-discrete element method (FDEM), which merges the finite element method (FEM) and the discrete element method (DEM), is used to explicitly simulate a sheared granular fault system including both gouge and plate, and to investigate the influence of different normal loads on seismic moment, macroscopic friction coefficient, kinetic energy, gouge layer thickness, and recurrence time between slips. In the FDEM model, the deformation of plates and particles is simulated using the FEM formulation whilemore » particle-particle and particle-plate interactions are modeled using DEM-derived techniques. The simulated seismic moment distributions are generally consistent with those obtained from the laboratory experiments. In addition, the simulation results demonstrate that with increasing normal load, (i) the kinetic energy of the granular fault system increases; (ii) the gouge layer thickness shows a decreasing trend; and (iii) the macroscopic friction coefficient does not experience much change. Analyses of the slip events reveal that, as the normal load increases, more slip events with large kinetic energy release and longer recurrence time occur, and the magnitude of gouge layer thickness decrease also tends to be larger; while the macroscopic friction coefficient drop decreases. Finally, the simulations not only reveal the influence of normal loads on the dynamics of sheared granular fault gouge, but also demonstrate the capabilities of FDEM for studying stick-slip dynamic behavior of granular fault systems.« less

Modeling of Stick-Slip Behavior in Sheared Granular Fault Gouge Using the Combined Finite-Discrete Element Method

DOE PAGES

Gao, Ke; Euser, Bryan J.; Rougier, Esteban; ...

2018-06-20

Sheared granular layers undergoing stick-slip behavior are broadly employed to study the physics and dynamics of earthquakes. In this paper, a two-dimensional implementation of the combined finite-discrete element method (FDEM), which merges the finite element method (FEM) and the discrete element method (DEM), is used to explicitly simulate a sheared granular fault system including both gouge and plate, and to investigate the influence of different normal loads on seismic moment, macroscopic friction coefficient, kinetic energy, gouge layer thickness, and recurrence time between slips. In the FDEM model, the deformation of plates and particles is simulated using the FEM formulation whilemore » particle-particle and particle-plate interactions are modeled using DEM-derived techniques. The simulated seismic moment distributions are generally consistent with those obtained from the laboratory experiments. In addition, the simulation results demonstrate that with increasing normal load, (i) the kinetic energy of the granular fault system increases; (ii) the gouge layer thickness shows a decreasing trend; and (iii) the macroscopic friction coefficient does not experience much change. Analyses of the slip events reveal that, as the normal load increases, more slip events with large kinetic energy release and longer recurrence time occur, and the magnitude of gouge layer thickness decrease also tends to be larger; while the macroscopic friction coefficient drop decreases. Finally, the simulations not only reveal the influence of normal loads on the dynamics of sheared granular fault gouge, but also demonstrate the capabilities of FDEM for studying stick-slip dynamic behavior of granular fault systems.« less

ngs (notochord granular surface) gene encodes a novel type of intermediate filament family protein essential for notochord maintenance in zebrafish.

PubMed

Tong, Xiangjun; Xia, Zhidan; Zu, Yao; Telfer, Helena; Hu, Jing; Yu, Jingyi; Liu, Huan; Zhang, Quan; Sodmergen; Lin, Shuo; Zhang, Bo

2013-01-25

The notochord is an important organ involved in embryonic patterning and locomotion. In zebrafish, the mature notochord consists of a single stack of fully differentiated, large vacuolated cells called chordocytes, surrounded by a single layer of less differentiated notochordal epithelial cells called chordoblasts. Through genetic analysis of zebrafish lines carrying pseudo-typed retroviral insertions, a mutant exhibiting a defective notochord with a granular appearance was isolated, and the corresponding gene was identified as ngs (notochord granular surface), which was specifically expressed in the notochord. In the mutants, the notochord started to degenerate from 32 hours post-fertilization, and the chordocytes were then gradually replaced by smaller cells derived from chordoblasts. The granular notochord phenotype was alleviated by anesthetizing the mutant embryos with tricaine to prevent muscle contraction and locomotion. Phylogenetic analysis showed that ngs encodes a new type of intermediate filament (IF) family protein, which we named chordostatin based on its function. Under the transmission electron microcopy, bundles of 10-nm-thick IF-like filaments were enriched in the chordocytes of wild-type zebrafish embryos, whereas the chordocytes in ngs mutants lacked IF-like structures. Furthermore, chordostatin-enhanced GFP (EGFP) fusion protein assembled into a filamentous network specifically in chordocytes. Taken together, our work demonstrates that ngs encodes a novel type of IF protein and functions to maintain notochord integrity for larval development and locomotion. Our work sheds light on the mechanisms of notochord structural maintenance, as well as the evolution and biological function of IF family proteins.

ngs (Notochord Granular Surface) Gene Encodes a Novel Type of Intermediate Filament Family Protein Essential for Notochord Maintenance in Zebrafish*

PubMed Central

Tong, Xiangjun; Xia, Zhidan; Zu, Yao; Telfer, Helena; Hu, Jing; Yu, Jingyi; Liu, Huan; Zhang, Quan; Sodmergen; Lin, Shuo; Zhang, Bo

2013-01-01

The notochord is an important organ involved in embryonic patterning and locomotion. In zebrafish, the mature notochord consists of a single stack of fully differentiated, large vacuolated cells called chordocytes, surrounded by a single layer of less differentiated notochordal epithelial cells called chordoblasts. Through genetic analysis of zebrafish lines carrying pseudo-typed retroviral insertions, a mutant exhibiting a defective notochord with a granular appearance was isolated, and the corresponding gene was identified as ngs (notochord granular surface), which was specifically expressed in the notochord. In the mutants, the notochord started to degenerate from 32 hours post-fertilization, and the chordocytes were then gradually replaced by smaller cells derived from chordoblasts. The granular notochord phenotype was alleviated by anesthetizing the mutant embryos with tricaine to prevent muscle contraction and locomotion. Phylogenetic analysis showed that ngs encodes a new type of intermediate filament (IF) family protein, which we named chordostatin based on its function. Under the transmission electron microcopy, bundles of 10-nm-thick IF-like filaments were enriched in the chordocytes of wild-type zebrafish embryos, whereas the chordocytes in ngs mutants lacked IF-like structures. Furthermore, chordostatin-enhanced GFP (EGFP) fusion protein assembled into a filamentous network specifically in chordocytes. Taken together, our work demonstrates that ngs encodes a novel type of IF protein and functions to maintain notochord integrity for larval development and locomotion. Our work sheds light on the mechanisms of notochord structural maintenance, as well as the evolution and biological function of IF family proteins. PMID:23132861

Effect of induced cohesion on stick-slip dynamics in weakly saturated, sheared granular fault gouge

DOE PAGES

Dorostkar, Omid; Guyer, Robert A.; Johnson, Paul Allan; ...

2018-02-28

We use three-dimensional discrete element calculations to study stick-slip dynamics in a weakly wet granular layer designed to simulate fault gouge. The granular gouge is constituted by 8000 spherical particles with a poly-disperse size distribution. At very low liquid content, liquids impose cohesive and viscous forces on particles. Our simulations show that by increasing the liquid content, friction increases and granular layer shows higher recurrence time between slip events. We also observe that slip events exhibit larger friction drop and layer compaction in wet system compared to dry. We demonstrate that a small volume of liquid induces cohesive forces betweenmore » wet particles that are responsible for an increase in coordination number leading to a more stable arrangement of particles. This stabilization is evidenced with two orders of magnitude lower particle kinetic energy in wet system during stick phase. Similar to previous experimental studies, we observe enhanced frictional strength for wet granular layers. In experiments, the physicochemical processes are believed to be the main reason for such behavior, we show however, that at low confining stresses the hydromechanical effects of induced cohesion are sufficient for observed behavior. Our simulations illuminate the role of particle interactions and demonstrate the conditions under which induced cohesion plays a significant role in fault zone processes, including slip initiation, weakening, and failure.« less

Effect of induced cohesion on stick-slip dynamics in weakly saturated, sheared granular fault gouge

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dorostkar, Omid; Guyer, Robert A.; Johnson, Paul Allan

We use three-dimensional discrete element calculations to study stick-slip dynamics in a weakly wet granular layer designed to simulate fault gouge. The granular gouge is constituted by 8000 spherical particles with a poly-disperse size distribution. At very low liquid content, liquids impose cohesive and viscous forces on particles. Our simulations show that by increasing the liquid content, friction increases and granular layer shows higher recurrence time between slip events. We also observe that slip events exhibit larger friction drop and layer compaction in wet system compared to dry. We demonstrate that a small volume of liquid induces cohesive forces betweenmore » wet particles that are responsible for an increase in coordination number leading to a more stable arrangement of particles. This stabilization is evidenced with two orders of magnitude lower particle kinetic energy in wet system during stick phase. Similar to previous experimental studies, we observe enhanced frictional strength for wet granular layers. In experiments, the physicochemical processes are believed to be the main reason for such behavior, we show however, that at low confining stresses the hydromechanical effects of induced cohesion are sufficient for observed behavior. Our simulations illuminate the role of particle interactions and demonstrate the conditions under which induced cohesion plays a significant role in fault zone processes, including slip initiation, weakening, and failure.« less

Cohesion-Induced Stabilization in Stick-Slip Dynamics of Weakly Wet, Sheared Granular Fault Gouge

NASA Astrophysics Data System (ADS)

Dorostkar, Omid; Guyer, Robert A.; Johnson, Paul A.; Marone, Chris; Carmeliet, Jan

2018-03-01

We use three-dimensional discrete element calculations to study stick-slip dynamics in a weakly wet granular layer designed to simulate fault gouge. The granular gouge is constituted by 8,000 spherical particles with a polydisperse size distribution. At very low liquid content, liquids impose cohesive and viscous forces on particles. Our simulations show that by increasing the liquid content, friction increases and granular layer shows higher recurrence time between slip events. We also observe that slip events exhibit larger friction drop and layer compaction in wet system compared to dry. We demonstrate that a small volume of liquid induces cohesive forces between wet particles that are responsible for an increase in coordination number leading to a more stable arrangement of particles. This stabilization is evidenced with 2 orders of magnitude lower particle kinetic energy in wet system during stick phase. Similar to previous experimental studies, we observe enhanced frictional strength for wet granular layers. In experiments, the physicochemical processes are believed to be the main reason for such behavior; we show, however, that at low confining stresses, the hydromechanical effects of induced cohesion are sufficient for observed behavior. Our simulations illuminate the role of particle interactions and demonstrate the conditions under which induced cohesion plays a significant role in fault zone processes, including slip initiation, weakening, and failure.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Hsin; Simunovic, Srdjan; Maleki, Hosein

The response of Li-ion cells to mechanically induced internal electrical shorts is an important safety performance metric design. We assume that the battery internal configuration at the onset of electrical short influences the subsequent response and can be used to gauge the safety risk. We subjected a series of prismatic Li-ion cells to lateral pinching using 0.25", 0.5", 1", 2" and 3" diameter steel balls until the onset of internal short. The external aluminum enclosure froze the internal cell configuration at the onset of short and enabled us to cross-section the cells, and take the cross-section images. The images indicatemore » that an internal electric short is preceded by extensive strain partitioning in the cells, fracturing and tearing of the current collectors, and cracking and slipping of the electrode layers with multiple fault lines across multiple layers. These observations are at odds with a common notion of homogeneous deformation across the layers and strain hardening of electrodes that eventually punch through the separator and short the cell. The faults are akin to tectonic movements of multiple layers that are characteristic of granular materials and bonded aggregates. As a result, the short circuits occur after extensive internal faulting, which implies significant stretching and tearing of separators.« less

Whole-genome sequencing of a malignant granular cell tumor with metabolic response to pazopanib

PubMed Central

Wei, Lei; Liu, Song; Conroy, Jeffrey; Wang, Jianmin; Papanicolau-Sengos, Antonios; Glenn, Sean T.; Murakami, Mitsuko; Liu, Lu; Hu, Qiang; Conroy, Jacob; Miles, Kiersten Marie; Nowak, David E.; Liu, Biao; Qin, Maochun; Bshara, Wiam; Omilian, Angela R.; Head, Karen; Bianchi, Michael; Burgher, Blake; Darlak, Christopher; Kane, John; Merzianu, Mihai; Cheney, Richard; Fabiano, Andrew; Salerno, Kilian; Talati, Chetasi; Khushalani, Nikhil I.; Trump, Donald L.; Johnson, Candace S.; Morrison, Carl D.

2015-01-01

Granular cell tumors are an uncommon soft tissue neoplasm. Malignant granular cell tumors comprise <2% of all granular cell tumors, are associated with aggressive behavior and poor clinical outcome, and are poorly understood in terms of tumor etiology and systematic treatment. Because of its rarity, the genetic basis of malignant granular cell tumor remains unknown. We performed whole-genome sequencing of one malignant granular cell tumor with metabolic response to pazopanib. This tumor exhibited a very low mutation rate and an overall stable genome with local complex rearrangements. The mutation signature was dominated by C>T transitions, particularly when immediately preceded by a 5′ G. A loss-of-function mutation was detected in a newly recognized tumor suppressor candidate, BRD7. No mutations were found in known targets of pazopanib. However, we identified a receptor tyrosine kinase pathway mutation in GFRA2 that warrants further evaluation. To the best of our knowledge, this is only the second reported case of a malignant granular cell tumor exhibiting a response to pazopanib, and the first whole-genome sequencing of this uncommon tumor type. The findings provide insight into the genetic basis of malignant granular cell tumors and identify potential targets for further investigation. PMID:27148567

Studies on the toxic effects of pentachlorophenol on the biological activity of anaerobic granular sludge.

PubMed

Liu, Xin-Wen; He, Ruo; Shen, Dong-Sheng

2008-09-01

In order to explore the pathway of the anaerobic biotreatment of the wastewater containing pentachlorophenol (PCP) and ensure the normal operation of Upflow Anaerobic Sludge Blanket (UASB) reactor, the anaerobic sludge under different acclimation conditions were selected to seed and start up UASB reactors. Anaerobic toxicity assays were employed to study the biological activity, the tolerance and the capacity to degrade PCP of different anaerobic granular sludge from UASB reactors. Results showed that the anaerobic granular sludge acclimated to chlorophenols (CPs) could degrade PCP more quickly (up to 9.50mg-PCP g(-1)TVS d(-1)). And the anaerobic granular sludge without acclimation to CPs had only a little activity of degrading PCP (less than 0.07 mg-PCP g(-1)TVS d(-1)). Different PCP concentrations (2, 4, 6, 8 mg L(-1)) had different inhibition effects on glucose utilization, volatile fatted acidity (VFA)-degrading and methanogens activity of PCP degradation anaerobic granular sludge, and the biological activity declined with the increase in PCP concentration. The methanogens activity suffered inhibition from PCP more easily. The different acclimation patterns of seeded sludge had distinctly different effects on biological activity of the degradation of PCP of anaerobic granular sludge from UASB reactors. The biological activity of the anaerobic granular sludge acclimated to PCP only was also inhibited. This inhibition was weak compared to that of anaerobic granular sludge acclimated to CPs, further, the activity could recover more quickly in this case. In the same reactor, the anaerobic granular sludge from the mid and base layers showed higher tolerance to PCP than that from super layer or if the sludge is unacclimated to CPs, and the corresponding recovery time of the biological activity in the mid and base layers were short. Acetate-utilizing methanogens and syntrophic propinate degraders were sensitive to PCP, compared to syntrophic butyrate degraders.

[Skin changes in albinism in persons of the Negroid race (light- and electron-microscopy studies].

PubMed

Semkin, V I; Mikhaĭlov, I N

1984-01-01

The skin of the negroid race albinos is studied light- and electron-microscopically. Morphological alterations, as compared to control, consist of the horny layer thickening, increase of the cellularity in the epidermis, appearance of numerous pronounced tonofibrillar-keratohyaline complexes in the granular cells and a well developed network of dense bundles of tonofibrils in the spinous layer. Melanocytes and Langerhans cells are similar by their structure and number to those in the control. The protein skeletons of melanosomes in keratinocytes and melanocytes are practically unchanged but they are completely deprived of melanine biopolymer. The dermal macrophages do not contain a melanin pigment. The morphological features of the albinos epidermis, particularly the horny layer thickening, increase of the cellularity and the presence of pronounced tonofibrillar-keratohyaline complexes represent most likely a compensatory protective mechanism against ultraviolet radiation.

Phase-coexisting patterns, horizontal segregation, and controlled convection in vertically vibrated binary granular mixtures

NASA Astrophysics Data System (ADS)

Ansari, Istafaul Haque; Rivas, Nicolas; Alam, Meheboob

2018-01-01

We report patterns consisting of coexistence of synchronous and asynchronous states [for example, a granular gas co-existing with (i) bouncing bed, (ii) undulatory subharmonic waves, and (iii) Leidenfrost-like states] in experiments on vertically vibrated binary granular mixtures in a Hele-Shaw cell. Most experiments have been carried out with equimolar binary mixtures of glass and steel balls of same diameter by varying the total layer height (F ) for a range of shaking acceleration (Γ ). All patterns as well as the related phase diagram in the (Γ ,F ) plane have been reproduced via molecular dynamics simulations of the same system. The segregation of heavier and lighter particles along the horizontal direction is shown to be the progenitor of such phase-coexisting patterns as confirmed in both experiment and simulation. At strong shaking we uncover a partial convection state in which a pair of convection rolls is found to coexist with a Leidenfrost-like state. The crucial role of the relative number density of two species on controlling the buoyancy-driven granular convection is demonstrated. The onset of horizontal segregation can be explained in terms of an anisotropic diffusion tensor.

Neurons of the Dentate Molecular Layer in the Rabbit Hippocampus

PubMed Central

Sancho-Bielsa, Francisco J.; Navarro-López, Juan D.; Alonso-Llosa, Gregori; Molowny, Asunción; Ponsoda, Xavier; Yajeya, Javier; López-García, Carlos

2012-01-01

The molecular layer of the dentate gyrus appears as the main entrance gate for information into the hippocampus, i.e., where the perforant path axons from the entorhinal cortex synapse onto the spines and dendrites of granule cells. A few dispersed neuronal somata appear intermingled in between and probably control the flow of information in this area. In rabbits, the number of neurons in the molecular layer increases in the first week of postnatal life and then stabilizes to appear permanent and heterogeneous over the individuals’ life span, including old animals. By means of Golgi impregnations, NADPH histochemistry, immunocytochemical stainings and intracellular labelings (lucifer yellow and biocytin injections), eight neuronal morphological types have been detected in the molecular layer of developing adult and old rabbits. Six of them appear as interneurons displaying smooth dendrites and GABA immunoreactivity: those here called as globoid, vertical, small horizontal, large horizontal, inverted pyramidal and polymorphic. Additionally there are two GABA negative types: the sarmentous and ectopic granular neurons. The distribution of the somata and dendritic trees of these neurons shows preferences for a definite sublayer of the molecular layer: small horizontal, sarmentous and inverted pyramidal neurons are preferably found in the outer third of the molecular layer; vertical, globoid and polymorph neurons locate the intermediate third, while large horizontal and ectopic granular neurons occupy the inner third or the juxtagranular molecular layer. Our results reveal substantial differences in the morphology and electrophysiological behaviour between each neuronal archetype in the dentate molecular layer, allowing us to propose a new classification for this neural population. PMID:23144890

Neurons of the dentate molecular layer in the rabbit hippocampus.

PubMed

Sancho-Bielsa, Francisco J; Navarro-López, Juan D; Alonso-Llosa, Gregori; Molowny, Asunción; Ponsoda, Xavier; Yajeya, Javier; López-García, Carlos

2012-01-01

The molecular layer of the dentate gyrus appears as the main entrance gate for information into the hippocampus, i.e., where the perforant path axons from the entorhinal cortex synapse onto the spines and dendrites of granule cells. A few dispersed neuronal somata appear intermingled in between and probably control the flow of information in this area. In rabbits, the number of neurons in the molecular layer increases in the first week of postnatal life and then stabilizes to appear permanent and heterogeneous over the individuals' life span, including old animals. By means of Golgi impregnations, NADPH histochemistry, immunocytochemical stainings and intracellular labelings (lucifer yellow and biocytin injections), eight neuronal morphological types have been detected in the molecular layer of developing adult and old rabbits. Six of them appear as interneurons displaying smooth dendrites and GABA immunoreactivity: those here called as globoid, vertical, small horizontal, large horizontal, inverted pyramidal and polymorphic. Additionally there are two GABA negative types: the sarmentous and ectopic granular neurons. The distribution of the somata and dendritic trees of these neurons shows preferences for a definite sublayer of the molecular layer: small horizontal, sarmentous and inverted pyramidal neurons are preferably found in the outer third of the molecular layer; vertical, globoid and polymorph neurons locate the intermediate third, while large horizontal and ectopic granular neurons occupy the inner third or the juxtagranular molecular layer. Our results reveal substantial differences in the morphology and electrophysiological behaviour between each neuronal archetype in the dentate molecular layer, allowing us to propose a new classification for this neural population.

Computed tomography and magnetic resonance imaging findings of intraorbital granular cell tumor (Abrikossoff's tumor): a case report.

PubMed

Yuan, Wei-Hsin; Lin, Tai-Chi; Lirng, Jiing-Feng; Guo, Wan-You; Chang, Fu-Pang; Ho, Donald Ming-Tak

2016-05-13

Granular cell tumors are rare neoplasms which can occur in any part of the body. Granular cell tumors of the orbit account for only 3 % of all granular cell tumor cases. Computed tomography and magnetic resonance imaging of the orbit have proven useful for diagnosing orbital tumors. However, the rarity of intraorbital granular cell tumors poses a significant diagnostic challenge for both clinicians and radiologists. We report a case of a 37-year-old Chinese woman with a rare intraocular granular cell tumor of her right eye presenting with diplopia, proptosis, and restriction of ocular movement. Preoperative orbital computed tomography and magnetic resonance imaging with contrast enhancement revealed an enhancing solid, ovoid, well-demarcated, retrobulbar nodule. In addition, magnetic resonance imaging features included an intraorbital tumor which was isointense relative to gray matter on T1-weighted imaging and hypointense on T2-weighted imaging. No diffusion restriction of water was noted on either axial diffusion-weighted images or apparent diffusion coefficient maps. Both computed tomography and magnetic resonance imaging features suggested an intraorbital hemangioma. However, postoperative pathology (together with immunohistochemistry) identified an intraorbital granular cell tumor. When intraorbital T2 hypointensity and free diffusion of water are observed on magnetic resonance imaging, a granular cell tumor should be included in the differential diagnosis of an intraocular tumor.

Spindle cell oncocytomas and granular cell tumors of the pituitary are variants of pituicytoma.

PubMed

Mete, Ozgur; Lopes, Maria Beatriz; Asa, Sylvia L

2013-11-01

Pituicytomas are neoplasms that arise from pituicytes, which are specialized glia of the posterior pituitary. Pituicytes have 5 ultrastructural variants: light, dark, granular, ependymal, and oncocytic. Granular cell tumors of the pituitary gland are thought to arise from granular pituicytes. Spindle cell oncocytomas are considered to arise from folliculostellate cells, which are sustentacular cells of the adenohypophysis. Recent data suggest that, whereas pituicytes and all 3 tumor types are positive for TTF-1, folliculostellate cells are negative for TTF-1. We investigated 7 spindle cell oncocytomas, 4 pituicytomas, and 3 granular cell tumors for their genetic (BRAF(V600E) mutation and BRAF-KIAA fusion), immunohistochemical (GFAP, vimentin, S100 protein, olig2, IDH1-R132H, NF, galectin-3, chromogranin-A, CD56, EMA, CAM5.2, CD68, TTF-1, and bcl-2), and ultrastructural features to refine their classification. All tumors had nuclear positivity for TTF-1 and were negative for CAM5.2, chromogranin-A, and NF. GFAP, vimentin, S100, galectin-3, EMA, and CD68 were variably positive in the majority of the 3 tumor groups. Olig2 was only positive in 1 pituicytoma. Whereas granular cell tumors were negative for bcl-2 and CD56, pituicytomas and spindle cell oncocytomas showed variable positivity. All tumors were negative with the IDH1-R132H mutation-specific antibody, and none had evidence of BRAF alterations (BRAF(V600E) mutation and BRAF-KIAA fusion). Diffuse TTF-1 expression in nontumorous pituicytes, pituicytomas, spindle cell oncocytomas, and granular cell tumors indicates a common pituicyte lineage. The ultrastructural variants of pituicytes are reflected in these 3 morphologic variants of tumors arising from these cells. We propose the terminology "oncocytic pituicytomas" and "granular cell pituicytomas" to refine the classification of these lesions.

Stopping dynamics of a steady uniform granular flow over a rough incline

NASA Astrophysics Data System (ADS)

Deboeuf, Stéphanie; Saingier, Guillaume; Thiruvalluvar, Nitharshini; Lagrée, Pierre-Yves; Popinet, Stéphane; Staron, Lydie

2017-06-01

Granular material flowing on complex topographies are ubiquitous in industrial and geophysical situations. Even model granular flows are difficult to understand and predict. Recently, the frictional rheology μ(I) -describing the ratio of the shear stress to the normal stress as a function of the inertial number I, that compares inertial and confinement effects- allows unifying different configurations of granular flows. However it does not succeed in describing some phenomenologies, such as creep flow, deposit height, … Is it attributable to the rheology, to non-local effects, ...? Here, we consider a thin layer of grains flowing steadily and uniformly on a rough incline, when the input mass flow rate is suddenly stopped. We focus on the arrest dynamics by using both experimental and numerical approaches. We measure the height and surface velocities of the granular layer during the long-time stopping dynamics and we compare our experimental results with computations of depthaveraged equations for a fluid of rheology μ(I).

Morphology of the Epidermis of the Neotropical Catfish Pimelodella lateristriga (Lichtenstein, 1823) with Emphasis in Club Cells

PubMed Central

Damasceno, Eduardo Medeiros; Monteiro, Juliana Castro; Duboc, Luiz Fernando; Dolder, Heidi; Mancini, Karina

2012-01-01

The epidermis of Ostariophysi fish is composed of 4 main cell types: epidermal cells (or filament containing cells), mucous cells, granular cells and club cells. The morphological analysis of the epidermis of the catfish Pimelodella lateristriga revealed the presence of only two types of cells: epidermal and club cells. The latter were evident in the middle layer of the epidermis, being the largest cells within the epithelium. Few organelles were located in the perinuclear region, while the rest of the cytoplasm was filled with a non-vesicular fibrillar substance. Club cells contained two irregular nuclei with evident nucleoli and high compacted peripheral chromatin. Histochemical analysis detected prevalence of protein within the cytoplasm other than carbohydrates, which were absent. These characteristics are similar to those described to most Ostariophysi studied so far. On the other hand, the epidermal cells differ from what is found in the literature. The present study described three distinct types, as follows: superficial, abundant and dense cells. Differences among them were restricted to their cytoplasm and nucleus morphology. Mucous cells were found in all Ostariophysi studied so far, although they were absent in P. lateristriga, along with granular cells, also typical of other catfish epidermis. The preset study corroborates the observations on club cells' morphology in Siluriformes specimens, and shows important differences in epidermis composition and cell structure of P. lateristriga regarding the literature data. PMID:23226253

Granular cell tumor in an endangered Puerto Rican Amazon parrot (Amazon vittata)

USGS Publications Warehouse

Quist, C.F.; Latimer, K.S.; Goldade, S.L.; Rivera, A.; Dein, F.J.

1999-01-01

A 3 cm diameter mass from the metacarpus of a Puerto Rican Amazon parrot was diagnosed as a granular cell tumour based on light microscopy. The cytoplasmic granules were periodic-acid Schiff positive and diastase resistant. Ultrastructural characteristics of the cells included convoluted nuclei and the presence of numerous cytoplasmic tertiary lysosomes. This is only the second granular cell tumour reported in a bird. We speculate that most granular cell tumours are derived from cells that are engaged in some type of cellular degradative process, creating a similar morphologic appearance, but lacking a uniform histogenesis.

The effects of early hypo- and hyperthyroidism on the development of rat cerebellar cortex. III. Kinetics of cell proliferation in the external granular layer.

PubMed

Lauder, J M

1977-04-22

The effects of early hypo- and hyperthyroidism on the rates of cell acquisition and proliferation have been studied in the external granular layer (EGL) of the developing rat cerebellar cortex at 10 days of age using quantitative autoradiographic methods. Both altered thyroid states reduce the rate of cell acquisition in the EGL, but appear to do so for different reasons. Hyperthyroidism shortens the average length of the cell cycle by decreasing the duration of the pre-DNA synthetic phase (G1), indicating that excess thyroxine may exert a direct effect on the EGL. This action involves the early onset of neuronal differentiation (cessation of proliferation)46 which presumably leads to the observed decrease in the rate of cell acquisition (increased doubling time). Such differentiating cells do not, however, leave the proliferative zone or the EGL prematurely, resulting in a reduced labeling index, mitotic index, and growth fraction as non-dividing cells dilute the proliferating cell population. Hypothyroidism, on the other hand, leads to no significant change in the length of the cell cycle or in the mitotic index, but causes a decreased labeling index and growth fraction, as well as a reduced rate of cell acquisition (increased doubling time). No significant change in the amount of cell death in the EGL could be found to explain this apparent discrepancy between the rate of cell proliferation (cell cycle length) and cell acqusiition. The answer to this puzzle appears to lie in the mitotic index, which is not affected to the same extent as the labeling index, although it is also slightly reduced. If cells were to remain longer in mitosis, this could result in a decreased labeling index and growth fraction but nearly normal mitotic index and cell cycle length (as measured using the % labeled mitoses method), since those cells dropping out of the cycling population would be counted as mitoses...

Central granular cell odontogenic tumor: immunohistochemistry and ultrastructure.

PubMed

Meer, Shabnum; Altini, Mario; Coleman, Hedley; Daya, Nilesh

2004-01-01

Central granular cell odontogenic tumors are rare, with only 30 cases having been reported. The tumors usually occur in the mandibular molar area and are seen as localized painless swellings in patients older than 40 years. We report an additional case that occurred in the posterior mandible of an elderly black woman. All reported cases of this tumor are benign, and cure is effected by localized surgical excision. Ultrastructurally, the cells contain numerous lysosomes and phagocytic vacuoles. Immunohistochemically, the granular cells were positive for vimentin, CD68, muramidase, carcinogenic embryonic antigen, and bcl-2. These features support a mesenchymal origin with a possible histiocytic lineage for the granular cells. Awareness of the occurrence of this neoplasm is important to promote detection and differentiation from other intraoral granular cell lesions.

Investigation of sub-slab pressure field extension in specified granular fill materials incorporating a sump-based soil depressurisation system for radon mitigation.

PubMed

Hung, Le Chi; Goggins, Jamie; Fuente, Marta; Foley, Mark

2018-05-14

Design of bearing layers (granular fill material layers) is important for a house with a soil depressurisation (SD) system for indoor radon mitigation. These layers should not only satisfy the bearing capacity and serviceability criteria but should also provide a sufficient degree of the air permeability for the system. Previous studies have shown that a critical parameter for a SD system is the sub-slab pressure field extension in the bearing layers, but this issue has not been systematically investigated. A series of two-dimensional computational fluid dynamic simulations that investigate the behaviour of the sub-slab pressure field extension developed in a SD system is presented in this paper. The SD system considered in this paper consists of a granular fill material layer and a radon sump. The granular fill materials are 'T1 Struc' and 'T2 Perm', which are standard materials for building in the Republic of Ireland. Different conditions, which might be encountered in a practical situation, were examined. The results show that the air permeability and thickness of the granular fill materials are the two key factors which affect the sub slab pressure field extension (SPFE) significantly. Furthermore, the air permeability of native soil is found to be a fundamental factor for the SPFE so that it should be well understood when designing a SD system. Therefore, these factors should be considered sufficiently in each practical situation. Finally, a significant improvement of the pressure field extension can be achieved by ensuring air tightness of the SD system. Copyright © 2018 Elsevier B.V. All rights reserved.

Internal configuration of prismatic lithium-ion cells at the onset of mechanically induced short circuit

DOE PAGES

Wang, Hsin; Simunovic, Srdjan; Maleki, Hosein; ...

2016-01-01

The response of Li-ion cells to mechanically induced internal electrical shorts is an important safety performance metric design. We assume that the battery internal configuration at the onset of electrical short influences the subsequent response and can be used to gauge the safety risk. We subjected a series of prismatic Li-ion cells to lateral pinching using 0.25", 0.5", 1", 2" and 3" diameter steel balls until the onset of internal short. The external aluminum enclosure froze the internal cell configuration at the onset of short and enabled us to cross-section the cells, and take the cross-section images. The images indicatemore » that an internal electric short is preceded by extensive strain partitioning in the cells, fracturing and tearing of the current collectors, and cracking and slipping of the electrode layers with multiple fault lines across multiple layers. These observations are at odds with a common notion of homogeneous deformation across the layers and strain hardening of electrodes that eventually punch through the separator and short the cell. The faults are akin to tectonic movements of multiple layers that are characteristic of granular materials and bonded aggregates. As a result, the short circuits occur after extensive internal faulting, which implies significant stretching and tearing of separators.« less

Functional morphology of femoral glands in the Tegu lizard, Tupinambis merianae.

PubMed

Chamut, Silvia; Valdez, Valeria García; Manes, Mario E

2009-04-01

Several lizards have femoral glands, which have an influence in various reproductive behaviors. In this paper we describe the morphological organization of the femoral glands in the Tegu, Tupinambis merianae, by means of light and electron microscopy. Even though these glands are present in both genders, secretions during the reproductive period can only be found in males. The glandular parenchyma, which is organized in numerous secretory units, consists of keratinocyte-like cells and granular cells. The holocrine secretion is constituted from both cells, which lose their integrity and become a semi-amorphous material, reinforced by keratin sheets. The discharges of each unit merge together into a solid cylinder of secretion, surrounded by epithelial cells, that is extruded to the exterior. The keratin sheets and epithelial layers that surround both the complete and partial secretions form a sort of structural support suitable for the type of territorial demarcation characteristic of the species. The granular cells, supposedly the producers of pheromones, are characterized by the presence of electron-dense granules and multilaminar membranous bodies that show ultrastructural changes of unknown function. The free granules in the secretion cylinder may act as pheromone deposits.

Discrete element modeling of free-standing wire-reinforced jammed granular columns

NASA Astrophysics Data System (ADS)

Iliev, Pavel S.; Wittel, Falk K.; Herrmann, Hans J.

2018-02-01

The use of fiber reinforcement in granular media is known to increase the cohesion and therefore the strength of the material. However, a new approach, based on layer-wise deployment of predetermined patterns of the fiber reinforcement has led self-confining and free-standing jammed structures to become viable. We have developed a novel model to simulate fiber-reinforced granular materials, which takes into account irregular particles and wire elasticity and apply it to study the stability of unconfined jammed granular columns.

Spreading of a granular droplet.

PubMed

Sánchez, Iván; Raynaud, Franck; Lanuza, José; Andreotti, Bruno; Clément, Eric; Aranson, Igor S

2007-12-01

The influence of controlled vibrations on the granular rheology is investigated in a specifically designed experiment in which a granular film spreads under the action of horizontal vibrations. A nonlinear diffusion equation is derived theoretically that describes the evolution of the deposit shape. A self-similar parabolic shape (the "granular droplet") and a spreading dynamics are predicted that both agree quantitatively with the experimental results. The theoretical analysis is used to extract effective friction coefficients between the base and the granular layer under sustained and controlled vibrations. A shear thickening regime characteristic of dense granular flows is evidenced at low vibration energy, both for glass beads and natural sand. Conversely, shear thinning is observed at high agitation.

Spreading of a granular droplet

NASA Astrophysics Data System (ADS)

Clement, Eric; Sanchez, Ivan; Raynaud, Franck; Lanuza, Jose; Andreotti, Bruno; Aranson, Igor

2008-03-01

The influence of controlled vibrations on the granular rheology is investigated in a specifically designed experiment in which a granular film spreads under the action of horizontal vibrations. A nonlinear diffusion equation is derived theoretically that describes the evolution of the deposit shape. A self-similar parabolic shape (the``granular droplet'') and a spreading dynamics are predicted that both agree quantitatively with the experimental results. The theoretical analysis is used to extract effective friction coefficients between the base and the granular layer under sustained and controlled vibrations. A shear thickening regime characteristic of dense granular flows is evidenced at low vibration energy, both for glass beads and natural sand. Conversely, shear thinning is observed at high agitation.

Spreading of a granular droplet

NASA Astrophysics Data System (ADS)

Sánchez, Iván; Raynaud, Franck; Lanuza, José; Andreotti, Bruno; Clément, Eric; Aranson, Igor S.

2007-12-01

The influence of controlled vibrations on the granular rheology is investigated in a specifically designed experiment in which a granular film spreads under the action of horizontal vibrations. A nonlinear diffusion equation is derived theoretically that describes the evolution of the deposit shape. A self-similar parabolic shape (the“granular droplet”) and a spreading dynamics are predicted that both agree quantitatively with the experimental results. The theoretical analysis is used to extract effective friction coefficients between the base and the granular layer under sustained and controlled vibrations. A shear thickening regime characteristic of dense granular flows is evidenced at low vibration energy, both for glass beads and natural sand. Conversely, shear thinning is observed at high agitation.

High Stimulus-Related Information in Barrel Cortex Inhibitory Interneurons

PubMed Central

Reyes-Puerta, Vicente; Kim, Suam; Sun, Jyh-Jang; Imbrosci, Barbara; Kilb, Werner; Luhmann, Heiko J.

2015-01-01

The manner in which populations of inhibitory (INH) and excitatory (EXC) neocortical neurons collectively encode stimulus-related information is a fundamental, yet still unresolved question. Here we address this question by simultaneously recording with large-scale multi-electrode arrays (of up to 128 channels) the activity of cell ensembles (of up to 74 neurons) distributed along all layers of 3–4 neighboring cortical columns in the anesthetized adult rat somatosensory barrel cortex in vivo. Using two different whisker stimulus modalities (location and frequency) we show that individual INH neurons – classified as such according to their distinct extracellular spike waveforms – discriminate better between restricted sets of stimuli (≤6 stimulus classes) than EXC neurons in granular and infra-granular layers. We also demonstrate that ensembles of INH cells jointly provide as much information about such stimuli as comparable ensembles containing the ~20% most informative EXC neurons, however presenting less information redundancy – a result which was consistent when applying both theoretical information measurements and linear discriminant analysis classifiers. These results suggest that a consortium of INH neurons dominates the information conveyed to the neocortical network, thereby efficiently processing incoming sensory activity. This conclusion extends our view on the role of the inhibitory system to orchestrate cortical activity. PMID:26098109

Localization of peroxisome proliferator-activated receptor alpha (PPARα) and N-acyl phosphatidylethanolamine phospholipase D (NAPE-PLD) in cells expressing the Ca2+-binding proteins calbindin, calretinin, and parvalbumin in the adult rat hippocampus

PubMed Central

Rivera, Patricia; Arrabal, Sergio; Vargas, Antonio; Blanco, Eduardo; Serrano, Antonia; Pavón, Francisco J.; Rodríguez de Fonseca, Fernando; Suárez, Juan

2014-01-01

The N-acylethanolamines (NAEs), oleoylethanolamide (OEA) and palmithylethanolamide (PEA) are known to be endogenous ligands of PPARα receptors, and their presence requires the activation of a specific phospholipase D (NAPE-PLD) associated with intracellular Ca2+ fluxes. Thus, the identification of a specific population of NAPE-PLD/PPARα-containing neurons that express selective Ca2+-binding proteins (CaBPs) may provide a neuroanatomical basis to better understand the PPARα system in the brain. For this purpose, we used double-label immunofluorescence and confocal laser scanning microscopy for the characterization of the co-existence of NAPE-PLD/PPARα and the CaBPs calbindin D28k, calretinin and parvalbumin in the rat hippocampus. PPARα expression was specifically localized in the cell nucleus and, occasionally, in the cytoplasm of the principal cells (dentate granular and CA pyramidal cells) and some non-principal cells of the hippocampus. PPARα was expressed in the calbindin-containing cells of the granular cell layer of the dentate gyrus (DG) and the SP of CA1. These principal PPARα+/calbindin+ cells were closely surrounded by NAPE-PLD+ fiber varicosities. No pyramidal PPARα+/calbindin+ cells were detected in CA3. Most cells containing parvalbumin expressed both NAPE-PLD and PPARα in the principal layers of the DG and CA1/3. A small number of cells containing PPARα and calretinin was found along the hippocampus. Scattered NAPE-PLD+/calretinin+ cells were specifically detected in CA3. NAPE-PLD+ puncta surrounded the calretinin+ cells localized in the principal cells of the DG and CA1. The identification of the hippocampal subpopulations of NAPE-PLD/PPARα-containing neurons that express selective CaBPs should be considered when analyzing the role of NAEs/PPARα-signaling system in the regulation of hippocampal functions. PMID:24672435

Localization of peroxisome proliferator-activated receptor alpha (PPARα) and N-acyl phosphatidylethanolamine phospholipase D (NAPE-PLD) in cells expressing the Ca(2+)-binding proteins calbindin, calretinin, and parvalbumin in the adult rat hippocampus.

PubMed

Rivera, Patricia; Arrabal, Sergio; Vargas, Antonio; Blanco, Eduardo; Serrano, Antonia; Pavón, Francisco J; Rodríguez de Fonseca, Fernando; Suárez, Juan

2014-01-01

The N-acylethanolamines (NAEs), oleoylethanolamide (OEA) and palmithylethanolamide (PEA) are known to be endogenous ligands of PPARα receptors, and their presence requires the activation of a specific phospholipase D (NAPE-PLD) associated with intracellular Ca(2+) fluxes. Thus, the identification of a specific population of NAPE-PLD/PPARα-containing neurons that express selective Ca(2+)-binding proteins (CaBPs) may provide a neuroanatomical basis to better understand the PPARα system in the brain. For this purpose, we used double-label immunofluorescence and confocal laser scanning microscopy for the characterization of the co-existence of NAPE-PLD/PPARα and the CaBPs calbindin D28k, calretinin and parvalbumin in the rat hippocampus. PPARα expression was specifically localized in the cell nucleus and, occasionally, in the cytoplasm of the principal cells (dentate granular and CA pyramidal cells) and some non-principal cells of the hippocampus. PPARα was expressed in the calbindin-containing cells of the granular cell layer of the dentate gyrus (DG) and the SP of CA1. These principal PPARα(+)/calbindin(+) cells were closely surrounded by NAPE-PLD(+) fiber varicosities. No pyramidal PPARα(+)/calbindin(+) cells were detected in CA3. Most cells containing parvalbumin expressed both NAPE-PLD and PPARα in the principal layers of the DG and CA1/3. A small number of cells containing PPARα and calretinin was found along the hippocampus. Scattered NAPE-PLD(+)/calretinin(+) cells were specifically detected in CA3. NAPE-PLD(+) puncta surrounded the calretinin(+) cells localized in the principal cells of the DG and CA1. The identification of the hippocampal subpopulations of NAPE-PLD/PPARα-containing neurons that express selective CaBPs should be considered when analyzing the role of NAEs/PPARα-signaling system in the regulation of hippocampal functions.

PubMed Central

BARBIERI, M.; MUSIZZANO, Y.; BOGGIO, M.; CARCUSCIA, C.

2011-01-01

SUMMARY Granular cell tumour is a rare soft tissue neoplasm that can virtually affect any site of the body. Its histological origin is controversial, since several studies have shown that different cells are involved. Granular cell tumour was initially described as myoblastoma, but, at present, a neural origin is supported by most Authors, due to the immunohistochemical pattern. Even if the biological behaviour of granular cell tumours is usually benign, accurate histological examination is mandatory, because in a small number of cases they can be malignant. Here, a case is described of granular cell tumour in a 14-year-old boy, which is a very rare occurrence, since these tumours typically manifest in subjects between the third and sixth decade. Histopathological features, differential diagnosis and therapeutic implications of granular cell tumour are discussed, together with a brief review of the recent literature. PMID:22058595

Synthesis of prolyl 4-hydroxylase alpha subunit and type IV collagen in hemocytic granular cells of silkworm, Bombyx mori: Involvement of type IV collagen in self-defense reaction and metamorphosis.

PubMed

Adachi, Takahiro; Tomita, Masahiro; Yoshizato, Katsutoshi

2005-04-01

The present study shows that hemocytic granular cells synthesize and secrete type IV collagen (ColIV) in the silkworm Bombyx mori (B. mori) and suggests that these cells play roles in the formation of basement membrane, the encapsulation of foreign bodies, and the metamorphic remodeling of the gut. The full- and partial-length cDNA of B. mori prolyl 4-hydroxylase alpha subunit (BmP4Halpha) and B. mori ColIV (BmColIV) were cloned, respectively. In situ hybridization and immunocytochemistry on larval tissues and cells identified hemocytic granular cells as the cells that express mRNAs and proteins of both BmP4Halpha and BmColIV. Immunohistochemistry and immunocytochemistry demonstrated that BmColIV was present in the basement membrane and in the secretory granules of granular cells, respectively. Granular cells in culture secreted BmColIV without accompanying the degranulation and discharged it from the granules when the cells were degranulated. Nylon threads were inserted into the hemocoel of larvae. Granular cells concentrated around the nylon threads and encapsulated them as a self-defense reaction. BmColIV was found to be a component of the capsules. Furthermore, the present study showed that actively BmColIV-expressing granular cells accumulated around the midgut epithelium and formed BmColIV-rich thick basal lamina-like structures there in larval to pupal metamorphosis.

Simulating stick-slip failure in a sheared granular layer using a physics-based constitutive model

DOE PAGES

Lieou, Charles K. C.; Daub, Eric G.; Guyer, Robert A.; ...

2017-01-14

In this paper, we model laboratory earthquakes in a biaxial shear apparatus using the Shear-Transformation-Zone (STZ) theory of dense granular flow. The theory is based on the observation that slip events in a granular layer are attributed to grain rearrangement at soft spots called STZs, which can be characterized according to principles of statistical physics. We model lab data on granular shear using STZ theory and document direct connections between the STZ approach and rate-and-state friction. We discuss the stability transition from stable shear to stick-slip failure and show that stick slip is predicted by STZ when the applied shearmore » load exceeds a threshold value that is modulated by elastic stiffness and frictional rheology. Finally, we also show that STZ theory mimics fault zone dilation during the stick phase, consistent with lab observations.« less

Improved performance by morphology control via fullerenes in PBDT-TBT-alkoBT based organic solar cells

DOE PAGES

Khatiwada, Devendra; Venkatesan, Swaminathan; Chen, QIliang; ...

2015-07-03

In this work, we report improved performance by controlling morphology using different fullerene derivatives in poly{2-octyldodecyloxy-benzo[1,2-b;3,4-b]dithiophene-alt-5,6-bis(dodecyloxy)-4,7- di(thieno[3,2-b]thiophen-2-yl)-benzo[c][1,2,5]thiadiazole} (PBDT-TBT-alkoBT) based organic solar cells. PC60BM and PC70BM fullerenes were used to investigate the characteristic change in morphology and device performance. Fullerene affects device efficiency by changing active layer morphology. PC70BM with broader absorption than PC 60BM resulted in reduced device performance which was elucidated by the intermixed granular morphology separating each larger grain in the PC70BM/polymer composite layer which created higher density of traps. However after adding additive 1,8-diiodooctane (DIO), the fibrous morphology was observed due to reduced solubility of polymer andmore » increased solubility of PC 70BM in chloroform. The fibrous morphology improved charge transport leading to increase in overall device performance. Atomic force microscopies (AFM), photo induced charge extraction by linearly increasing voltage (photo-CELIV), and Kelvin prove force microscope (KPFM) were used to investigate nanoscale morphology of active layer with different fullerene derivatives. For PC 60BM based active layer, AFM images revealed dense fibrous morphology and more distinct fibrous morphology was observed by adding DIO. The PC 70BM based active layer only exhibited intermixed granular morphology instead of fibrous morphology observed in PC60BM based active layer. However, addition of DIO in PC 70BM based active layer led to fibrous morphology. When additive DIO was not used, a wider distribution of surface potential was observed for PC 70BM than PC 60BM based active layer by KPFM measurements, indicating 2 polymer and fullerene domains are separated. When DIO was used, narrower distribution of surface potential for both PC 70BM and PC 60BM based active layers was observed. Photo-CELIV experiment showed larger extracted charge carrier density and mobility in PC 70BM/DIO film.« less

Improved performance by morphology control via fullerenes in PBDT-TBT-alkoBT based organic solar cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Khatiwada, Devendra; Venkatesan, Swaminathan; Chen, QIliang

In this work, we report improved performance by controlling morphology using different fullerene derivatives in poly{2-octyldodecyloxy-benzo[1,2-b;3,4-b]dithiophene-alt-5,6-bis(dodecyloxy)-4,7- di(thieno[3,2-b]thiophen-2-yl)-benzo[c][1,2,5]thiadiazole} (PBDT-TBT-alkoBT) based organic solar cells. PC60BM and PC70BM fullerenes were used to investigate the characteristic change in morphology and device performance. Fullerene affects device efficiency by changing active layer morphology. PC70BM with broader absorption than PC 60BM resulted in reduced device performance which was elucidated by the intermixed granular morphology separating each larger grain in the PC70BM/polymer composite layer which created higher density of traps. However after adding additive 1,8-diiodooctane (DIO), the fibrous morphology was observed due to reduced solubility of polymer andmore » increased solubility of PC 70BM in chloroform. The fibrous morphology improved charge transport leading to increase in overall device performance. Atomic force microscopies (AFM), photo induced charge extraction by linearly increasing voltage (photo-CELIV), and Kelvin prove force microscope (KPFM) were used to investigate nanoscale morphology of active layer with different fullerene derivatives. For PC 60BM based active layer, AFM images revealed dense fibrous morphology and more distinct fibrous morphology was observed by adding DIO. The PC 70BM based active layer only exhibited intermixed granular morphology instead of fibrous morphology observed in PC60BM based active layer. However, addition of DIO in PC 70BM based active layer led to fibrous morphology. When additive DIO was not used, a wider distribution of surface potential was observed for PC 70BM than PC 60BM based active layer by KPFM measurements, indicating 2 polymer and fullerene domains are separated. When DIO was used, narrower distribution of surface potential for both PC 70BM and PC 60BM based active layers was observed. Photo-CELIV experiment showed larger extracted charge carrier density and mobility in PC 70BM/DIO film.« less

Terminal velocity of liquids and granular materials dispersed by a high explosive

NASA Astrophysics Data System (ADS)

Loiseau, J.; Pontalier, Q.; Milne, A. M.; Goroshin, S.; Frost, D. L.

2018-05-01

The explosive dispersal of a layer of solid particles or a layer of liquid surrounding a spherical high-explosive charge generates a turbulent, multiphase flow. Shock compression of the material layer during the initial acceleration may partially consolidate the material, leading to the formation of jet-like structures when the layer fragments and sheds particles upon release. Similarly, release of a shock-compressed liquid shell causes the nucleation of cavitation sites, leading to the radial breakup of the shell and the formation of jets upon expansion. In the current study, a wide variety of granular materials and liquids were explosively dispersed. The maximum terminal jet tip or shell velocity was measured using high-speed videography. Charges were constructed using thin-walled glass bulbs of various diameters and contained a central C-4 charge surrounded by the material to be dispersed. This permitted variation of the ratio of material mass to charge mass ( M/ C) from 4 to 300. Results indicated that material velocity broadly correlates with predictions of the Gurney model. For liquids, the terminal velocity was accurately predicted by the Gurney model. For granular materials, Gurney over-predicted the terminal velocity by 25-60%, depending on the M/ C ratio, with larger M/ C values exhibiting larger deficits. These deficits are explained by energy dissipation during the collapse of voids in the granular material bed. Velocity deficits were insensitive to the degree of jetting and granular material properties. Empirical corrections to the Gurney model are presented with improved agreement with the dry powder experimental velocities.

Terminal velocity of liquids and granular materials dispersed by a high explosive

NASA Astrophysics Data System (ADS)

Loiseau, J.; Pontalier, Q.; Milne, A. M.; Goroshin, S.; Frost, D. L.

2018-04-01

The explosive dispersal of a layer of solid particles or a layer of liquid surrounding a spherical high-explosive charge generates a turbulent, multiphase flow. Shock compression of the material layer during the initial acceleration may partially consolidate the material, leading to the formation of jet-like structures when the layer fragments and sheds particles upon release. Similarly, release of a shock-compressed liquid shell causes the nucleation of cavitation sites, leading to the radial breakup of the shell and the formation of jets upon expansion. In the current study, a wide variety of granular materials and liquids were explosively dispersed. The maximum terminal jet tip or shell velocity was measured using high-speed videography. Charges were constructed using thin-walled glass bulbs of various diameters and contained a central C-4 charge surrounded by the material to be dispersed. This permitted variation of the ratio of material mass to charge mass (M/C) from 4 to 300. Results indicated that material velocity broadly correlates with predictions of the Gurney model. For liquids, the terminal velocity was accurately predicted by the Gurney model. For granular materials, Gurney over-predicted the terminal velocity by 25-60%, depending on the M/C ratio, with larger M/C values exhibiting larger deficits. These deficits are explained by energy dissipation during the collapse of voids in the granular material bed. Velocity deficits were insensitive to the degree of jetting and granular material properties. Empirical corrections to the Gurney model are presented with improved agreement with the dry powder experimental velocities.

Cooperative transformation and coexpression of bovine papillomavirus type 1 E5 and E7 proteins.

PubMed

Bohl, J; Hull, B; Vande Pol, S B

2001-01-01

Productively infected bovine fibropapillomas were examined for bovine papillomavirus type 1 (BPV-1) E7 localization. BPV-1 E7 was observed in the cytoplasm of basal and lower spinous epithelial cells, coexpressed in the cytoplasm of basal cells with the E5 oncoprotein. E7 was also observed in nucleoli throughout the basal and spinous layers but not in the granular cell layer. Ectopic expression of E7 in cultured epithelial cells gave rise to localization similar to that seen in productive fibropapillomas, with cytoplasmic and nucleolar expression observed. Consistent with the coexpression of E7 and E5 in basal keratinocytes, BPV-1 E7 cooperated with E5 as well as E6 in an anchorage independence transformation assay. While E5 is expressed in both basal and superficial differentiating keratinocytes, BPV-1 E7 is only observed in basal and lower spinous epithelial cells. Therefore, BPV-1 E7 may serve to modulate the cellular response of basal epithelial cells to E5 expression.

Dual Gamma Rhythm Generators Control Interlaminar Synchrony in Auditory Cortex

PubMed Central

Ainsworth, Matthew; Lee, Shane; Cunningham, Mark O.; Roopun, Anita K.; Traub, Roger D.; Kopell, Nancy J.; Whittington, Miles A.

2013-01-01

Rhythmic activity in populations of cortical neurons accompanies, and may underlie, many aspects of primary sensory processing and short-term memory. Activity in the gamma band (30 Hz up to > 100 Hz) is associated with such cognitive tasks and is thought to provide a substrate for temporal coupling of spatially separate regions of the brain. However, such coupling requires close matching of frequencies in co-active areas, and because the nominal gamma band is so spectrally broad, it may not constitute a single underlying process. Here we show that, for inhibition-based gamma rhythms in vitro in rat neocortical slices, mechanistically distinct local circuit generators exist in different laminae of rat primary auditory cortex. A persistent, 30 – 45 Hz, gap-junction-dependent gamma rhythm dominates rhythmic activity in supragranular layers 2/3, whereas a tonic depolarization-dependent, 50 – 80 Hz, pyramidal/interneuron gamma rhythm is expressed in granular layer 4 with strong glutamatergic excitation. As a consequence, altering the degree of excitation of the auditory cortex causes bifurcation in the gamma frequency spectrum and can effectively switch temporal control of layer 5 from supragranular to granular layers. Computational modeling predicts the pattern of interlaminar connections may help to stabilize this bifurcation. The data suggest that different strategies are used by primary auditory cortex to represent weak and strong inputs, with principal cell firing rate becoming increasingly important as excitation strength increases. PMID:22114273

What Is the Evidence for Inter-laminar Integration in a Prefrontal Cortical Minicolumn?

PubMed

Opris, Ioan; Chang, Stephano; Noga, Brian R

2017-01-01

The objective of this perspective article is to examine columnar inter-laminar integration during the executive control of behavior. The integration hypothesis posits that perceptual and behavioral signals are integrated within the prefrontal cortical inter-laminar microcircuits. Inter-laminar minicolumnar activity previously recorded from the dorsolateral prefrontal cortex (dlPFC) of nonhuman primates, trained in a visual delay match-to-sample (DMS) task, was re-assessed from an integrative perspective. Biomorphic multielectrode arrays (MEAs) played a unique role in the in vivo recording of columnar cell firing in the dlPFC layers 2/3 and 5/6. Several integrative aspects stem from these experiments: 1. Functional integration of perceptual and behavioral signals across cortical layers during executive control. The integrative effect of dlPFC minicolumns was shown by: (i) increased correlated firing on correct vs. error trials; (ii) decreased correlated firing when the number of non-matching images increased; and (iii) similar spatial firing preference across cortical-striatal cells during spatial-trials, and less on object-trials. 2. Causal relations to integration of cognitive signals by the minicolumnar turbo-engines. The inter-laminar integration between the perceptual and executive circuits was facilitated by stimulating the infra-granular layers with firing patterns obtained from supra-granular layers that enhanced spatial preference of percent correct performance on spatial trials. 3. Integration across hierarchical levels of the brain. The integration of intention signals (visual spatial, direction) with movement preparation (timing, velocity) in striatum and with the motor command and posture in midbrain is also discussed. These findings provide evidence for inter-laminar integration of executive control signals within brain's prefrontal cortical microcircuits.

Reduction of intergranular exchange coupling and grain size for high Ku CoPt-based granular media: Metal-oxide buffer layer and multiple oxide boundary materials

NASA Astrophysics Data System (ADS)

Tham, Kim Kong; Kushibiki, Ryosuke; Kamada, Tomonari; Hinata, Shintaro; Saito, Shin

2018-05-01

Investigation of magnetic properties and microstructure of granular media with various multiple oxides as the grain boundary material is reported. Saturation magnetization (Ms), uniaxial magnetocrystalline anisotropy (Ku), and magnetic grain diameter (GD) of the granular media show linear correlation with volume weighted average for melting point (Tm) of each oxides (Tmave). Ku of magnetic grains (Kugrain) shows a trade-off relation with GD that it is a big challenge to satisfy both high Kugrain and small GD by only controlling Tmave. To obtain a granular medium with appropriate Kugrain, GD, and low degree of intergranular exchange coupling, the combination of Tmave control of grain boundary material by mixing oxides and employment of a buffer layer are required. Here the degree of intergranular exchange coupling is estimated from the slope of M-H loop at around coercivity (α). By applying this technique, a typical granular medium with Kugrain of 1.0×107 erg/cm3, GD of 5.1 nm, and α of 1.2 is realized.

Mitotic events in cerebellar granule progenitor cells that expand cerebellar surface area are critical for normal cerebellar cortical lamination in mice.

PubMed

Chang, Joshua C; Leung, Mark; Gokozan, Hamza Numan; Gygli, Patrick Edwin; Catacutan, Fay Patsy; Czeisler, Catherine; Otero, José Javier

2015-03-01

Late embryonic and postnatal cerebellar folial surface area expansion promotes cerebellar cortical cytoarchitectural lamination. We developed a streamlined sampling scheme to generate unbiased estimates of murine cerebellar surface area and volume using stereologic principles. We demonstrate that, during the proliferative phase of the external granular layer (EGL) and folial surface area expansion, EGL thickness does not change and thus is a topological proxy for progenitor self-renewal. The topological constraints indicate that, during proliferative phases, migration out of the EGL is balanced by self-renewal. Progenitor self-renewal must, therefore, include mitotic events yielding 2 cells in the same layer to increase surface area (β events) and mitotic events yielding 2 cells, with 1 cell in a superficial layer and 1 cell in a deeper layer (α events). As the cerebellum grows, therefore, β events lie upstream of α events. Using a mathematical model constrained by the measurements of volume and surface area, we could quantify intermitotic times for β events on a per-cell basis in postnatal mouse cerebellum. Furthermore, we found that loss of CCNA2, which decreases EGL proliferation and secondarily induces cerebellar cortical dyslamination, shows preserved α-type events. Thus, CCNA2-null cerebellar granule progenitor cells are capable of self-renewal of the EGL stem cell niche; this is concordant with prior findings of extensive apoptosis in CCNA2-null mice. Similar methodologies may provide another layer of depth to the interpretation of results from stereologic studies.

Three-dimensional virtual histology of human cerebellum by X-ray phase-contrast tomography.

PubMed

Töpperwien, Mareike; van der Meer, Franziska; Stadelmann, Christine; Salditt, Tim

2018-06-18

To quantitatively evaluate brain tissue and its corresponding function, knowledge of the 3D cellular distribution is essential. The gold standard to obtain this information is histology, a destructive and labor-intensive technique where the specimen is sliced and examined under a light microscope, providing 3D information at nonisotropic resolution. To overcome the limitations of conventional histology, we use phase-contrast X-ray tomography with optimized optics, reconstruction, and image analysis, both at a dedicated synchrotron radiation endstation, which we have equipped with X-ray waveguide optics for coherence and wavefront filtering, and at a compact laboratory source. As a proof-of-concept demonstration we probe the 3D cytoarchitecture in millimeter-sized punches of unstained human cerebellum embedded in paraffin and show that isotropic subcellular resolution can be reached at both setups throughout the specimen. To enable a quantitative analysis of the reconstructed data, we demonstrate automatic cell segmentation and localization of over 1 million neurons within the cerebellar cortex. This allows for the analysis of the spatial organization and correlation of cells in all dimensions by borrowing concepts from condensed-matter physics, indicating a strong short-range order and local clustering of the cells in the granular layer. By quantification of 3D neuronal "packing," we can hence shed light on how the human cerebellum accommodates 80% of the total neurons in the brain in only 10% of its volume. In addition, we show that the distribution of neighboring neurons in the granular layer is anisotropic with respect to the Purkinje cell dendrites. Copyright © 2018 the Author(s). Published by PNAS.

Imaging Cell Wall Architecture in Single Zinnia elegans Tracheary Elements1[OA

PubMed Central

Lacayo, Catherine I.; Malkin, Alexander J.; Holman, Hoi-Ying N.; Chen, Liang; Ding, Shi-You; Hwang, Mona S.; Thelen, Michael P.

2010-01-01

The chemical and structural organization of the plant cell wall was examined in Zinnia elegans tracheary elements (TEs), which specialize by developing prominent secondary wall thickenings underlying the primary wall during xylogenesis in vitro. Three imaging platforms were used in conjunction with chemical extraction of wall components to investigate the composition and structure of single Zinnia TEs. Using fluorescence microscopy with a green fluorescent protein-tagged Clostridium thermocellum family 3 carbohydrate-binding module specific for crystalline cellulose, we found that cellulose accessibility and binding in TEs increased significantly following an acidified chlorite treatment. Examination of chemical composition by synchrotron radiation-based Fourier-transform infrared spectromicroscopy indicated a loss of lignin and a modest loss of other polysaccharides in treated TEs. Atomic force microscopy was used to extensively characterize the topography of cell wall surfaces in TEs, revealing an outer granular matrix covering the underlying meshwork of cellulose fibrils. The internal organization of TEs was determined using secondary wall fragments generated by sonication. Atomic force microscopy revealed that the resulting rings, spirals, and reticulate structures were composed of fibrils arranged in parallel. Based on these combined results, we generated an architectural model of Zinnia TEs composed of three layers: an outermost granular layer, a middle primary wall composed of a meshwork of cellulose fibrils, and inner secondary wall thickenings containing parallel cellulose fibrils. In addition to insights in plant biology, studies using Zinnia TEs could prove especially productive in assessing cell wall responses to enzymatic and microbial degradation, thus aiding current efforts in lignocellulosic biofuel production. PMID:20592039

The Granular Blasius Problem: High inertial number granular flows

NASA Astrophysics Data System (ADS)

Tsang, Jonathan; Dalziel, Stuart; Vriend, Nathalie

2017-11-01

The classical Blasius problem considers the formation of a boundary layer through the change at x = 0 from a free-slip to a no-slip boundary beneath an otherwise steady uniform flow. Discrete particle model (DPM) simulations of granular gravity currents show that a similar phenomenon exists for a steady flow over a uniformly sloped surface that is smooth upstream (allowing slip) but rough downstream (imposing a no-slip condition). The boundary layer is a region of high shear rate and therefore high inertial number I; its dynamics are governed by the asymptotic behaviour of the granular rheology as I -> ∞ . The μ(I) rheology asserts that dμ / dI = O(1 /I2) as I -> ∞ , but current experimental evidence is insufficient to confirm this. We show that `generalised μ(I) rheologies', with different behaviours as I -> ∞ , all permit the formation of a boundary layer. We give approximate solutions for the velocity profile under each rheology. The change in boundary condition considered here mimics more complex topography in which shear stress increases in the streamwise direction (e.g. a curved slope). Such a system would be of interest in avalanche modelling. EPSRC studentship (Tsang) and Royal Society Dorothy Hodgkin Fellowship (Vriend).

Modeling interface shear behavior of granular materials using micro-polar continuum approach

NASA Astrophysics Data System (ADS)

Ebrahimian, Babak; Noorzad, Ali; Alsaleh, Mustafa I.

2018-01-01

Recently, the authors have focused on the shear behavior of interface between granular soil body and very rough surface of moving bounding structure. For this purpose, they have used finite element method and a micro-polar elasto-plastic continuum model. They have shown that the boundary conditions assumed along the interface have strong influences on the soil behavior. While in the previous studies, only very rough bounding interfaces have been taken into account, the present investigation focuses on the rough, medium rough and relatively smooth interfaces. In this regard, plane monotonic shearing of an infinite extended narrow granular soil layer is simulated under constant vertical pressure and free dilatancy. The soil layer is located between two parallel rigid boundaries of different surface roughness values. Particular attention is paid to the effect of surface roughness of top and bottom boundaries on the shear behavior of granular soil layer. It is shown that the interaction between roughness of bounding structure surface and the rotation resistance of bounding grains can be modeled in a reasonable manner through considered Cosserat boundary conditions. The influence of surface roughness is investigated on the soil shear strength mobilized along the interface as well as on the location and evolution of shear localization formed within the layer. The obtained numerical results have been qualitatively compared with experimental observations as well as DEM simulations, and acceptable agreement is shown.

Stress Increases the Negative Effects of Chronic Pain on Hippocampal Neurogenesis.

PubMed

Romero-Grimaldi, Carmen; Berrocoso, Esther; Alba-Delgado, Cristina; Madrigal, Jose Luis M; Perez-Nievas, Beatriz G; Leza, Juan Carlos; Mico, Juan Antonio

2015-10-01

Patients with chronic pain often suffer from affective disorders and cognitive decline, which significantly impairs their quality of life. In addition, many of these patients also experience stress unrelated to their illness, which can aggravate their symptoms. These nociceptive inputs are received by the hippocampus, in which maladaptive neuroplastic changes may occur in the conditions of chronic pain. The hippocampus is a structure involved in emotionality, learning, and memory, and the proliferating cells in the granular layer of the hippocampal dentate gyrus respond to chronic pain by slowing their turnover. However, whether the maturation, survival, and integration of newborn cells in the hippocampus are affected by chronic pain remains unclear. In addition, it is unknown whether an added stress may increase this effect. We have evaluated the proliferation, differentiation, and survival of newborn hippocampal cells in a rat model of neuropathic pain (chronic constriction injury), with or without stress (chronic immobilization), by assessing the incorporation of bromodeoxyuridine into proliferating cells and immunostaining. The data obtained indicated that there was a decrease in the number of proliferating cells 8 days after nerve injury in animals subjected to neuropathic pain, an effect that was exacerbated by stress. Moreover, 4 weeks after nerve injury, neuropathic pain was associated with a loss of neuroblasts and the reduced survival of new mature neurons in the hippocampal granular layer, phenomena that also were increased by stress. By contrast, the rate of differentiation was not affected in this paradigm. Neuropathic pain negatively influences hippocampal neurogenesis (proliferation and survival), and this effect is exacerbated by stress. These neuroplastic changes may account for the affective and cognitive impairment seen in patients with chronic pain.

The cytology of a thyroid granular cell tumor.

PubMed

Chang, Shu-Mei; Wei, Chang-Kuo; Tseng, Chih-En

2009-01-01

Granular cell tumor (GCT) of the thyroid is rare. Before this report, only four cases of thyroid GCT have been reported, none of which presented a cytopathological examination. In this paper, we report the fine needle aspiration cytology and pathological analysis of a thyroid GCT from a 12-year-old girl who presented with a painless neck mass. The tumor cells were single, in syncytial clusters, or pseudofollicles, contained small round, oval, or spindle nuclei, indistinct nucleoli, and a large amount of grayish, granular fragile cytoplasm. The background contained granular debris and naked nuclei. A differential diagnosis of thyroid GCT with more frequent thyroid lesions containing cytoplasmic granules, including Hurthle cells, macrophages, follicular cells, and cells of black thyroid syndrome, was also performed.

Intracortical circuits amplify sound-evoked activity in primary auditory cortex following systemic injection of salicylate in the rat

PubMed Central

Chrostowski, Michael; Salvi, Richard J.; Allman, Brian L.

2012-01-01

A high dose of sodium salicylate temporarily induces tinnitus, mild hearing loss, and possibly hyperacusis in humans and other animals. Salicylate has well-established effects on cochlear function, primarily resulting in the moderate reduction of auditory input to the brain. Despite decreased peripheral sensitivity and output, salicylate induces a paradoxical enhancement of the sound-evoked field potential at the level of the primary auditory cortex (A1). Previous electrophysiologic studies have begun to characterize changes in thalamorecipient layers of A1; however, A1 is a complex neural circuit with recurrent intracortical connections. To describe the effects of acute systemic salicylate treatment on both thalamic and intracortical sound-driven activity across layers of A1, we applied current-source density (CSD) analysis to field potentials sampled across cortical layers in the anesthetized rat. CSD maps were normally characterized by a large, short-latency, monosynaptic, thalamically driven sink in granular layers followed by a lower amplitude, longer latency, polysynaptic, intracortically driven sink in supragranular layers. Following systemic administration of salicylate, there was a near doubling of both granular and supragranular sink amplitudes at higher sound levels. The supragranular sink amplitude input/output function changed from becoming asymptotic at approximately 50 dB to sharply nonasymptotic, often dominating the granular sink amplitude at higher sound levels. The supragranular sink also exhibited a significant decrease in peak latency, reflecting an acceleration of intracortical processing of the sound-evoked response. Additionally, multiunit (MU) activity was altered by salicylate; the normally onset/sustained MU response type was transformed into a primarily onset response type in granular and infragranular layers. The results from CSD analysis indicate that salicylate significantly enhances sound-driven response via intracortical circuits. PMID:22496535

Spatiotemporal patterns in reaction-diffusion system and in a vibrated granular bed

DOE Office of Scientific and Technical Information (OSTI.GOV)

Swinney, H.L.; Lee, K.J.; McCormick, W.D.

Experiments on a quasi-two-dimensional reaction-diffusion system reveal transitions from a uniform state to stationary hexagonal, striped, and rhombic spatial patterns. For other reactor conditions lamellae and self-replicating spot patterns are observed. These patterns form in continuously fed thin gel reactors that can be maintained indefinitely in well-defined nonequilibrium states. Reaction-diffusion models with two chemical species yield patterns similar to those observed in the experiments. Pattern formation is also being examined in vertically oscillated thin granular layers (typically 3-30 particle diameters deep). For small acceleration amplitudes, a granular layer is flat, but above a well-defined critical acceleration amplitude, spatial patterns spontaneouslymore » form. Disordered time-dependent granular patterns are observed as well as regular patterns of squares, stripes, and hexagons. A one-dimensional model consisting of a completely inelastic ball colliding with a sinusoidally oscillating platform provides a semi-quantitative description of most of the observed bifurcations between the different spatiotemporal regimes.« less

Stationary bubble formation and cavity collapse in wedge-shaped hoppers

PubMed Central

Yagisawa, Yui; Then, Hui Zee; Okumura, Ko

2016-01-01

The hourglass is one of the apparatuses familiar to everyone, but reveals intriguing behaviors peculiar to granular materials, and many issues are remained to be explored. In this study, we examined the dynamics of falling sand in a special form of hourglass, i.e., a wedge-shaped hopper, when a suspended granular layer is stabilized to a certain degree. As a result, we found remarkably different dynamic regimes of bubbling and cavity. In the bubbling regime, bubbles of nearly equal size are created in the sand at a regular time interval. In the cavity regime, a cavity grows as sand beads fall before a sudden collapse of the cavity. Bubbling found here is quite visible to a level never discussed in the physics literature and the cavity regime is a novel phase, which is neither continuous, intermittent nor completely blocked phase. We elucidate the physical conditions necessary for the bubbling and cavity regimes and develop simple theories for the regimes to successfully explain the observed phenomena by considering the stability of a suspended granular layer and clogging of granular flow at the outlet of the hopper. The bubbling and cavity regimes could be useful for mixing a fluid with granular materials. PMID:27138747

Ultrastructural and functional characterization of circulating hemocytes from Galleria mellonella larva: Cell types and their role in the innate immunity.

PubMed

Wu, Gongqing; Liu, Yi; Ding, Ying; Yi, Yunhong

2016-08-01

Galleria mellonella larvae have been widely used as a model to study the virulence of various human pathogens. Hemocytes play important roles in the innate immune response of G. mellonella. In this study, the hemocytes of G. mellonella larvae were analyzed by transmission electron microscope, light microscope, and cytochemistry. The cytological and morphological analyses revealed four types of hemocytes; Plasmatocytes, granular cells, spherule cells and oenocytoids. Differential hemocyte counts showed that under our conditions plasmatocytes and granular cells were the most abundant circulating cell types in the hemolymph. We also investigated the role of different types of hemocytes in the cellular and humoral immune defenses. The in-vivo experiment showed that plasmatocytes, granular cells and oenocytoids phagocytized FITC-labelled Escherichia coli bacteria in larvae of G. mellonella, whereas the granular cells exhibited the strongest phagocytic ability against these microbial cells. After incubation with L-DOPA, plasmatocytes, granular cells and oenocytoids are stained brown, indicating the presence of phenoloxidase activity. These results shed new light on our understanding of the immune function of G. mellonella hemocytes. Copyright © 2016 Elsevier Ltd. All rights reserved.

Electrical transport properties in Fe-Cr nanocluster-assembled granular films

NASA Astrophysics Data System (ADS)

Wang, Xiong-Zhi; Wang, Lai-Sen; Zhang, Qin-Fu; Liu, Xiang; Xie, Jia; Su, A.-Mei; Zheng, Hong-Fei; Peng, Dong-Liang

2017-09-01

The Fe100-xCrx nanocluster-assembled granular films with Cr atomic fraction (x) ranging from 0 to 100 were fabricated by using a plasma-gas-condensation cluster deposition system. The TEM characterization revealed that the uniform Fe clusters were coated with a Cr layer to form a Fe-Cr core-shell structure. Then, the as-prepared Fe100-xCrx nanoclusters were randomly assembled into a granular film in vacuum environments with increasing the deposition time. Because of the competition between interfacial resistance and shunting effect of Cr layer, the room temperature resistivity of the Fe100-xCrx nanocluster-assembled granular films first increased and then decreased with increasing the Cr atomic fraction (x), and revealed a maximum of 2 × 104 μΩ cm at x = 26 at.%. The temperature-dependent longitudinal resistivity (ρxx), magnetoresistance (MR) effect and anomalous Hall effect (AHE) of these Fe100-xCrx nanocluster-assembled granular films were also studied systematically. As the x increased from 0 to 100, the ρxx of all samples firstly decreased and then increased with increasing the measuring temperature. The dependence of ρxx on temperature could be well addressed by a mechanism incorporated for the fluctuation-induced-tunneling (FIT) conduction process and temperature-dependent scattering effect. It was found that the anomalous Hall effect (AHE) had no legible scaling relation in Fe100-xCrx nanocluster-assembled granular films. However, after deducting the contribution of tunneling effect, the scaling relation was unambiguous. Additionally, the Fe100-xCrx nanocluster-assembled granular films revealed a small negative magnetoresistance (MR), which decreased with the increase of x. The detailed physical mechanism of the electrical transport properties in these Fe100-xCrx nanocluster-assembled granular films was also studied.

[Architectural ultrastructure of the human urinary transitional epithelium].

PubMed

Takayama, H; Konishi, T

1984-07-01

Human urinary bladder mucosa, confirmed to be normal by cystoscopic, histologic and bacteriologic examination, were obtained from four patients at prostatectomy and from two patients at an anti-VUR procedure. The luminal surface and the three dimensional architecture of the bladder mucosa were observed by scanning electron microscopy (SEM) after cryofracture of specimen and by transmission electron microscopy (TEM). The epithelium consists of superficial, intermediate and basal cells, and SEM and TEM showed that it was stratified. Intermediate cells reached the basal lamina by slender cytoplasmic processes but superficial cells were not directly in contact with the basal lamina. No pleomorphic or long microvilli were observed but short microvilli or granular protrusions were sparsely seen on the luminal surface of superficial cells. SEM of cryofractured surfaces revealed that cells from each cell layer were in contact with cellular junctions such as ridges, plicated projections and septum-like walls. Their junctions were more complicated with increasing depth of the cell layer. No pleomorphic or long microvilli were observed on any cell surface of the intermediate or basal cell layer. Under TEM, however, these junctional structures of ridges, plicated projections and septal walls appeared to be microvilli under TEM. Microvilli-like structures on TEM, therefore, have to be carefully distinguished from real microvilli. Careful observation is required when the presence of cells covered with microvilli is described as a sign of malignancy.

Hematopoietic organs of Manduca sexta and hemocyte lineages.

PubMed

Nardi, James B; Pilas, Barbara; Ujhelyi, Elizabeth; Garsha, Karl; Kanost, Michael R

2003-10-01

Cells of the moth immune system are derived from organs that loosely envelop the four wing imaginal discs. The immune response in these insects is believed to depend on the activities of two main classes of hemocytes: plasmatocytes and granular cells. The fates of cells that arise from these hematopoietic organs have been followed by immunolabeling with plasmatocyte-specific and granular-cell-specific antibodies. Cells within each hematopoietic organ differ in their coherence and in their expression of two plasmatocyte-specific surface proteins, integrin and neuroglian. Within an organ there is no overlap in the expression of these two surface proteins; neuroglian is found on the surfaces of the coherent cells while integrin is expressed on cells that are losing coherence, rounding up, and dispersing. A granular-cell-specific marker for the protein lacunin labels the basal lamina that delimits each organ but only a small number of granular cells that lie on or near the periphery of the hematopoietic organ. When organs are cultured in the absence of hemolymph, all cells derived from hematopoietic organs turn out to immunolabel with the plasmatocyte-specific antibody MS13. The circulating plasmatocytes derived from hematopoietic organs have higher ploidy levels than the granular cells and represent a separate lineage of hemocytes.

Abnormal Behaviors and Developmental Disorder of Hippocampus in Zinc Finger Protein 521 (ZFP521) Mutant Mice

PubMed Central

Ohkubo, Nobutaka; Matsubara, Etsuko; Yamanouchi, Jun; Akazawa, Rie; Aoto, Mamoru; Suzuki, Yoji; Sakai, Ikuya; Abe, Takaya; Kiyonari, Hiroshi; Matsuda, Seiji; Yasukawa, Masaki; Mitsuda, Noriaki

2014-01-01

Zinc finger protein 521 (ZFP521) regulates a number of cellular processes in a wide range of tissues, such as osteoblast formation and adipose commitment and differentiation. In the field of neurobiology, it is reported to be an essential factor for transition of epiblast stem cells into neural progenitors in vitro. However, the role of ZFP521 in the brain in vivo still remains elusive. To elucidate the role of ZFP521 in the mouse brain, we generated mice lacking exon 4 of the ZFP521 gene. The birth ratio of our ZFP521 Δ/Δ mice was consistent with Mendel's laws. Although ZFP521 Δ/Δ pups had no apparent defect in the body and were indistinguishable from ZFP521+/+ and ZFP521 +/Δ littermates at the time of birth, ZFP521 Δ/Δ mice displayed significant weight reduction as they grew, and most of them died before 10 weeks of age. They displayed abnormal behavior, such as hyper-locomotion, lower anxiety and impaired learning, which correspond to the symptoms of schizophrenia. The border of the granular cell layer of the dentate gyrus in the hippocampus of the mice was indistinct and granular neurons were reduced in number. Furthermore, Sox1-positive neural progenitor cells in the dentate gyrus and cerebellum were significantly reduced in number. Taken together, these findings indicate that ZFP521 directly or indirectly affects the formation of the neuronal cell layers of the dentate gyrus in the hippocampus, and thus ZFP521 Δ/Δ mice displayed schizophrenia-relevant symptoms. ZFP521 Δ/Δ mice may be a useful research tool as an animal model of schizophrenia. PMID:24676388

Intrauterine Growth Restriction Affects Cerebellar Granule Cells in the Developing Guinea Pig Brain.

PubMed

Tolcos, Mary; McDougall, Annie; Shields, Amy; Chung, Yoonyoung; O'Dowd, Rachael; Turnley, Ann; Wallace, Megan; Rees, Sandra

2018-01-01

Intrauterine growth restriction (IUGR) can lead to adverse neurodevelopmental sequelae in postnatal life. However, the effects of IUGR on the cerebellum are still to be fully elucidated. A major determinant of growth and development of the cerebellum is proliferation and subsequent migration of cerebellar granule cells. Our objective was to determine whether IUGR, induced by chronic placental insufficiency (CPI) in guinea pigs, results in abnormal cerebellar development due to deficits suggestive of impaired granule cell proliferation and/or migration. CPI was induced by unilateral ligation of the uterine artery at mid-gestation, producing growth-restricted (GR) foetuses at 52 and 60 days of gestation (dg), and neonates at 1 week postnatal age (term approx. 67 dg). Controls were from sham-operated animals. In GR foetuses compared with controls at 52 dg, the external granular layer (EGL) width and internal granular layer (IGL) area were similar. In GR foetuses compared with controls at 60 dg: (a) the EGL width was greater (p < 0.005); (b) the IGL area was smaller (p < 0.005); (c) the density of Ki67-negative (postmitotic) granule cells in the EGL was greater (p < 0.01); (d) the somal area of Purkinje cells was reduced (p < 0.005), and (e) the linear density of Bergmann glia was similar. The EGL width in GR foetuses at 60 dg was comparable to that of 52 dg control and GR foetuses. The pattern of p27-immunoreactivity in the EGL was the inverse of Ki67-immunoreactivity at both foetal ages; there was no difference between control and GR foetuses at either age in the width of p27-immunoreactivity, or in the percentage of the EGL width that it occupied. In the molecular layer of GR neonates compared with controls there was an increase in the areal density of granule cells (p < 0.05) and in the percentage of migrating to total number of granule cells (p < 0.01) at 1 week but not at 60 dg (p > 0.05). Thus, we found no specific evidence that IUGR affects granule cell proliferation, but it alters the normal program of migration to the IGL and, in addition, the development of Purkinje cells. Such alterations will likely affect the development of appropriate circuitry and have implications for cerebellar function. © 2018 S. Karger AG, Basel.

Parvalbumin and calbindin immunoreactivity in the cerebral cortex of the hedgehog (Erinaceus europaeus).

PubMed Central

Ferrer, I; Zujar, M J; Admella, C; Alcantara, S

1992-01-01

To investigate the morphology and distribution of nonpyramidal neurons in the brain of insectivores, parvalbumin and calbindin 28 kDa immunoreactivity was examined in the cerebral cortex of the hedgehog (Erinaceus europaeus). Parvalbumin-immunoreactive cells were found in all layers of the isocortex, but in contrast to other mammals, a laminar organisation or specific regional distribution was not seen. Characteristic parvalbumin-immunoreactive neurons were multipolar cells with large ascending and descending dendrites extending throughout several layers. Calbindin-immunoreactive neurons were similar to those found in other species, although appearing in smaller numbers than in the cerebral cortex of more advanced mammals. The morphology and distribution of parvalbumin- and calbindin-immunoreactive cells in the piriform and entorhinal cortices were similar in hedgehogs and rodents. Parvalbumin-immunoreactive cells in the hippocampal complex were pyramidal-like and bitufted neurons, which were mainly found in the stratum oriens and stratum pyramidale of the hippocampus, and in the stratum moleculare and hilus of the fascia dentata. Heavily stained cells were found in the deep part of the stratum granulare. Intense calbindin immunoreactivity occurred mainly in the granule cell and molecular layers of the dentate gyrus and in the mossy fibre layer. The most outstanding feature in the hippocampal complex of the hedgehog was the extension of calbindin immunoreactivity to CA1 field of the hippocampus, suggesting, in agreement with other reports, that mossy fibres can establish synaptic contacts throughout the pyramidal cell layer. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 PMID:1452472

Eosinophils.

PubMed

Radonjic-Hösli, Susanne; Simon, Hans-Uwe

2014-01-01

In 1846, T. Wharton-Jones described a coarsely granular stage in the development of granulocytic cells in animal and human blood. Shortly thereafter, Max Schultze redefined the coarsely granular cells as a type distinct from finely granular cells, rather than just a developmental stage. It was, however, not until 1879, when Paul Ehrlich introduced a method to distinguish granular cells by the staining properties of their granules, that a classification became possible. An intensive staining for eosin, among other aniline dyes, was eponymous for the coarsely granular cell type, which thereupon became referred to as eosinophil granulocyte. Eosinophilia had already been described in many diseases by the late 19th century. The role of these cells, however, today remains a matter of continuing speculation and investigation. Many functions have been attributed to the eosinophil over the years, often linked to increasing knowledge about the granular and cytoplasmatic contents. A better understanding of the regulatory mechanisms of eosinopoiesis has led to the development of knock-out mice strains as well as therapeutic strategies for reducing the eosinophil load in patients. The effect of these therapeutics and the characterization of the knock-out phenotypes have led to a great increase in the knowledge of the role of the eosinophil in disease. Today we think of the eosinophil as a multifunctional cell involved in host defense, tissue damage and remodeling, as well as immunomodulation. © 2014 S. Karger AG, Basel.

Boundary effects in a quasi-two-dimensional driven granular fluid.

PubMed

Smith, N D; Smith, M I

2017-12-01

The effect of a confining boundary on the spatial variations in granular temperature of a driven quasi-two-dimensional layer of particles is investigated experimentally. The radial drop in the relative granular temperature ΔT/T exhibits a maximum at intermediate particle numbers which coincides with a crossover from kinetic to collisional transport of energy. It is also found that at low particle numbers, the distributions of radial velocities are increasingly asymmetric as one approaches the boundary. The radial and tangential granular temperatures split, and in the tails of the radial velocity distribution there is a higher population of fast moving particles traveling away rather than towards the boundary.

Recirculation cells for granular flow in cylindrical rotating tumblers

NASA Astrophysics Data System (ADS)

D'Ortona, Umberto; Thomas, Nathalie; Lueptow, Richard M.

2018-05-01

To better understand the velocity field and flowing layer structure, we have performed a detailed discrete element method study of the flow of monodisperse particles in a partially filled three-dimensional cylindrical rotating tumblers. Similar to what occurs near the poles in spherical and conical tumblers, recirculation cells (secondary flows) develop near the flat endwalls of a cylindrical tumbler in which particles near the surface drift axially toward the endwall, while particles deeper in the flowing layer drift axially toward the midlength of the tumbler. Another recirculation cell with the opposite sense develops next to each endwall recirculation cell, extending to the midlength of the tumbler. For a long enough tumbler, each endwall cell is about one quarter of the tumbler diameter in length. Endwall cells are insensitive to tumbler length and relatively insensitive to rotation speed (so long as the flowing layer remains flat and continuously flowing) or fill level (from 25% to 50% full). However, for shorter tumblers (0.5 to 1.0 length/diameter aspect ratio) the endwall cell size does not change much, while center cells reduce their size and eventually disappear for the shortest tumblers. For longer tumblers (length/diameter aspect ratio larger than 2), a stagnation zone appears in between the central cells. These results provide insight into the mixing of monodisperse particles in rotating cylindrical tumblers as well as the frictional effects of the tumbler endwalls.

Challenges of Particle Flow reconstruction in the CMS High-Granularity Calorimeter at the High-Luminosity LHC

NASA Astrophysics Data System (ADS)

Chlebana, Frank; CMS Collaboration

2017-11-01

The challenges of the High-Luminosity LHC (HL-LHC) are driven by the large number of overlapping proton-proton collisions (pileup) in each bunch-crossing and the extreme radiation dose to detectors at high pseudorapidity. To overcome this challenge CMS is developing an endcap electromagnetic+hadronic sampling calorimeter employing silicon sensors in the electromagnetic and front hadronic sections, comprising over 6 million channels, and highly-segmented plastic scintillators in the rear part of the hadronic section. This High- Granularity Calorimeter (HGCAL) will be the first of its kind used in a colliding beam experiment. Clustering deposits of energy over many cells and layers is a complex and challenging computational task, particularly in the high-pileup environment of HL-LHC. Baseline detector performance results are presented for electromagnetic and hadronic objects, and studies demonstrating the advantages of fine longitudinal and transverse segmentation are explored.

Water drop dynamics on a granular layer

NASA Astrophysics Data System (ADS)

Llorens, Coraline; Biance, Anne-Laure; Ybert, Christophe; Pirat, Christophe; Liquids; Interfaces Team

2015-11-01

Liquid drop impacts, either on a solid surface or a liquid bath, have been studied for a while and are still subject of intense research. Less is known concerning impacts on granular layers that are shown to exhibit an intermediate situation between solid and liquid. In this study, we focus on water drop impacts on granular matter made of micrometer-sized spherical glass beads. In particular, we investigate the overall dynamics arising from the interplay between liquid and grains throughout the impact. Depending on the relevant parameters (impact velocity, drop and grain sizes, as well as their wetting properties), various behaviors are evidenced. In particular, the behavior of the beads at the liquid-gas interface (ball-bearing vs imbibition) is shown to greatly affect the spreading dynamics of the drop, as well as satellite droplets formation, beads ejection, and the final crater morphology.

Friction on a granular-continuum interface: Effects of granular media

NASA Astrophysics Data System (ADS)

Ecke, Robert; Geller, Drew

We consider the frictional interactions of two soft plates with interposed granular material subject to normal and shear forces. The plates are soft photo-elastic material, have length 50 cm, and are separated by a gap of variable width from 0 to 20 granular particle diameters. The granular materials are two-dimensional rods that are bi-dispersed in size to prevent crystallization. Different rod materials with frictional coefficients between 0 . 04 < μ < 0 . 5 are used to explore the effects of inter-granular friction on the effective friction of a granular medium. The gap is varied to test the dependence of the friction coefficient on the thickness of the granular layer. Because the soft plates absorb most of the displacement associated with the compressional normal force, the granular packing fractions are close to a jamming threshold, probably a shear jamming criterion. The overall shear and normal forces are measured using force sensors and the local strain tensor over a central portion of the gap is obtained using relative displacements of fiducial markers on the soft elastic material. These measurements provide a good characterization of the global and local forces giving rise to an effective friction coefficient. Funded by US DOE LDRD Program.

A two-phase solid/fluid model for dense granular flows including dilatancy effects

NASA Astrophysics Data System (ADS)

Mangeney, Anne; Bouchut, Francois; Fernandez-Nieto, Enrique; Koné, El-Hadj; Narbona-Reina, Gladys

2016-04-01

Describing grain/fluid interaction in debris flows models is still an open and challenging issue with key impact on hazard assessment [{Iverson et al.}, 2010]. We present here a two-phase two-thin-layer model for fluidized debris flows that takes into account dilatancy effects. It describes the velocity of both the solid and the fluid phases, the compression/dilatation of the granular media and its interaction with the pore fluid pressure [{Bouchut et al.}, 2016]. The model is derived from a 3D two-phase model proposed by {Jackson} [2000] based on the 4 equations of mass and momentum conservation within the two phases. This system has 5 unknowns: the solid and fluid velocities, the solid and fluid pressures and the solid volume fraction. As a result, an additional equation inside the mixture is necessary to close the system. Surprisingly, this issue is inadequately accounted for in the models that have been developed on the basis of Jackson's work [{Bouchut et al.}, 2015]. In particular, {Pitman and Le} [2005] replaced this closure simply by imposing an extra boundary condition at the surface of the flow. When making a shallow expansion, this condition can be considered as a closure condition. However, the corresponding model cannot account for a dissipative energy balance. We propose here an approach to correctly deal with the thermodynamics of Jackson's model by closing the mixture equations by a weak compressibility relation following {Roux and Radjai} [1998]. This relation implies that the occurrence of dilation or contraction of the granular material in the model depends on whether the solid volume fraction is respectively higher or lower than a critical value. When dilation occurs, the fluid is sucked into the granular material, the pore pressure decreases and the friction force on the granular phase increases. On the contrary, in the case of contraction, the fluid is expelled from the mixture, the pore pressure increases and the friction force diminishes. To account for this transfer of fluid into and out of the mixture, a two-layer model is proposed with a fluid layer on top of the two-phase mixture layer. Mass and momentum conservation are satisfied for the two phases, and mass and momentum are transferred between the two layers. A thin-layer approximation is used to derive average equations. Special attention is paid to the drag friction terms that are responsible for the transfer of momentum between the two phases and for the appearance of an excess pore pressure with respect to the hydrostatic pressure. We present several numerical tests of two-phase granular flows over sloping topography that are compared to the results of the model proposed by {Pitman and Le} [2005]. In particular, we quantify the role of the fluid and compression/dilatation processes on granular flow velocity field and runout distance. F. Bouchut, E.D. Fernandez-Nieto, A. Mangeney, G. Narbona-Reina, A two-phase shallow debris flow model with energy balance, {ESAIM: Math. Modelling Num. Anal.}, 49, 101-140 (2015). F. Bouchut, E. D. Fernandez-Nieto, A. Mangeney, G. Narbona-Reina, A two-phase two-layer model for fluidized granular flows with dilatancy effects, {J. Fluid Mech.}, submitted (2016). R.M. Iverson, M. Logan, R.G. LaHusen, M. Berti, The perfect debris flow? Aggregated results from 28 large-scale experiments, {J. Geophys. Res.}, 115, F03005 (2010). R. Jackson, The Dynamics of Fluidized Particles, {Cambridges Monographs on Mechanics} (2000). E.B. Pitman, L. Le, A two-fluid model for avalanche and debris flows, {Phil.Trans. R. Soc. A}, 363, 1573-1601 (2005). S. Roux, F. Radjai, Texture-dependent rigid plastic behaviour, {Proceedings: Physics of Dry Granular Media}, September 1997. (eds. H. J. Herrmann et al.). Kluwer. Cargèse, France, 305-311 (1998).

Clustering of adhesion receptors following exposure of insect blood cells to foreign surfaces.

PubMed

Nardi, James B; Zhuang, Shufei; Pilas, Barbara; Bee, Charles Mark; Kanost, Michael R

2005-05-01

Cell-mediated immune responses of insects involve interactions of two main classes of blood cells (hemocytes) known as granular cells and plasmatocytes. In response to a foreign surface, these hemocytes suddenly transform from circulating, non-adherent cells to cells that interact and adhere to each other and the foreign surface. This report presents evidence that during this adhesive transformation the extracellular matrix (ECM) proteins lacunin and a ligand for peanut agglutinin (PNA) lectin are released by granular cells and bind to surfaces of both granular cells and plasmatocytes. ECM protein co-localizes on cell surfaces with the adhesive receptors integrin and neuroglian, a member of the immunoglobulin superfamily. The ECM protein(s) secreted by granular cells are hypothesized to interact with adhesion receptors such as neuroglian and integrin by cross linking and clustering them on hemocyte surfaces. This clustering of receptors is known to enhance the adhesiveness (avidity) of interacting mammalian immune cells. The formation of ring-shaped clusters of these adhesion receptors on surfaces of insect immune cells represents an evolutionary antecedent of the mammalian immunological synapse.

Granular cell tumor of the esophagus. Report of three cases.

PubMed

Cohle, S D; McKechnie, J C; Truong, L; Jurco, S

1981-06-01

Granular cell tumors, (formerly called myoblastomas) involving the esophagus were encountered in three patients. In all three the tumors were asymptomatic and in two they were multiple. The first published endoscopic photographs of such a tumor are presented. The successful total removal of this neoplasm using the endoscope is described. The pathologic, radiologic and therapeutic aspects of previously reported cases of granular cell tumor of the esophagus are reviewed and compared with the three reported herein.

A therapeutic and diagnostic dilemma: granular cell tumor of the breast.

PubMed

Pergel, Ahmet; Yucel, Ahmet Fikret; Karaca, A Serdar; Aydin, Ibrahim; Sahin, Dursun Ali; Demirbag, Nilgun

2011-01-01

Six to eight percent of granular cell tumors are seen in the breast. Although mostly benign, they rarely have malignant features clinically and radiologically reminding of breast cancer. This may lead to a potential misdiagnosis of breast carcinoma and overtreatment of patients. The final diagnosis is made by immunohistochemical examination. We performed excisional biopsy on a patient who was diagnosed to have a breast mass. The histopathological examination of the mass revealed granular cell tumor.

Granular slumping on a horizontal surface

NASA Astrophysics Data System (ADS)

Lajeunesse, E.; Monnier, J. B.; Homsy, G. M.

2005-10-01

We report the results of an experimental investigation of the flow induced by the collapse of a column of granular material (glass beads of diameter d) over a horizontal surface. Two different setups are used, namely, a rectangular channel and a semicircular tube, allowing us to compare two-dimensional and axisymmetric flows, with particular focus on the internal flow structure. In both geometries the flow dynamics and the deposit morphologies are observed to depend primarily on the initial aspect ratio of the granular column a =Hi/Li, where Hi is the height of the initial granular column and Li its length along the flow direction. Two distinct regimes are observed depending on a: an avalanche of the column flanks producing truncated deposits for small a and a column free fall leading to conical deposits for large a. In both geometries the characteristic time scale is the free fall of the granular column τc=√Hi/g . The flow initiated by Coulomb-like failure never involves the whole granular heap but remains localized in a surface layer whose size and shape depend on a and vary in both space and time. Except in the vicinity of the pile foot where the flow is pluglike, velocity profiles measured at the side wall are identical to those commonly observed in steady granular surface flows: the velocity varies linearly with depth in the flowing layer and decreases exponentially with depth in the static layer. Moreover, the shear rate is constant, γ˙=0.3√g /d , independent of the initial aspect ratio, the flow geometry, position along the heap, or time. Despite the rather complex flow dynamics, the scaled deposit height Hf/Li and runout distance ΔL /Li both exhibit simple power laws whose exponents depend on a and on the flow geometry. We show that the physical origin of these power laws can be understood on the basis of a dynamic balance between acceleration, pressure gradient, and friction forces at the foot of the granular pile. Two asymptotic behaviors can be distinguished: the flow is dominated by friction forces at small a and by pressure forces at large a. The effect of the flow geometry is determined primarily by mass conservation and becomes important only for large a.

Blurring the boundary between rapid granular flow and dense granular flow regimes: Evidence from DEM simulations

NASA Astrophysics Data System (ADS)

Tripathi, Anurag; Prasad, Mahesh; Kumar, Puneet

2017-11-01

The saturation of the effective friction coefficient for granular flows at high inertial numbers has been assumed widely by researchers, despite little simulation/experimental evidence. In contrast, a recent simulation study of plane shear flows by Mandal and Khakhar, suggests that the effective friction coefficient becomes maximum and then starts to decrease with increase in the inertial number for I > 0.5 . In order to investigate whether such a dip at higher inertial numbers is indeed a feature of granular rheology, we perform DEM simulations of chute flow of highly inelastic disks. We show that steady, fully developed flows are possible at inclinations much higher than those normally reported in literature. At such high inclinations, the flow is characterised by a significant slip at the base; the height of the layer increases by more than 300 % and kinetic energy of the layer increases by nearly 5 orders of magnitude. We observe, for the first time, steady chute flows at inertial number I 2 and show that the dip at higher inertial numbers can be observed in case of chute flow as well. The predictions of modified μ - I rheology, however, seem to remain valid in the bulk of the layer for packing fractions as low as 0.2. AT acknowledges the funding obtained from IIT Kanpur through the initiation Grant for this study.

Size segregation in a granular bore

NASA Astrophysics Data System (ADS)

Edwards, A. N.; Vriend, N. M.

2016-10-01

We investigate the effect of particle-size segregation in an upslope propagating granular bore. A bidisperse mixture of particles, initially normally graded, flows down an inclined chute and impacts with a closed end. This impact causes the formation of a shock in flow thickness, known as a granular bore, to travel upslope, leaving behind a thick deposit. This deposit imprints the local segregated state featuring both pure and mixed regions of particles as a function of downstream position. The particle-size distribution through the depth is characterized by a thin purely small-particle layer at the base, a significant linear transition region, and a thick constant mixed-particle layer below the surface, in contrast to previously observed S-shaped steady-state concentration profiles. The experimental observations agree with recent progress that upward and downward segregation of large and small particles respectively is asymmetric. We incorporate the three-layer, experimentally observed, size-distribution profile into a depth-averaged segregation model to modify it accordingly. Numerical solutions of this model are able to match our experimental results and therefore motivate the use of a more general particle-size distribution profile.

A Therapeutic and Diagnostic Dilemma: Granular Cell Tumor of the Breast

PubMed Central

Pergel, Ahmet; Yucel, Ahmet Fikret; Karaca, A. Serdar; Aydin, Ibrahim; Sahin, Dursun Ali; Demirbag, Nilgun

2011-01-01

Six to eight percent of granular cell tumors are seen in the breast. Although mostly benign, they rarely have malignant features clinically and radiologically reminding of breast cancer. This may lead to a potential misdiagnosis of breast carcinoma and overtreatment of patients. The final diagnosis is made by immunohistochemical examination. We performed excisional biopsy on a patient who was diagnosed to have a breast mass. The histopathological examination of the mass revealed granular cell tumor. PMID:21547223

Conidial Hydrophobins of Aspergillus fumigatus

PubMed Central

Paris, Sophie; Debeaupuis, Jean-Paul; Crameri, Reto; Carey, Marilyn; Charlès, Franck; Prévost, Marie Christine; Schmitt, Christine; Philippe, Bruno; Latgé, Jean Paul

2003-01-01

The surface of Aspergillus fumigatus conidia, the first structure recognized by the host immune system, is covered by rodlets. We report that this outer cell wall layer contains two hydrophobins, RodAp and RodBp, which are found as highly insoluble complexes. The RODA gene was previously characterized, and ΔrodA conidia do not display a rodlet layer (N. Thau, M. Monod, B. Crestani, C. Rolland, G. Tronchin, J. P. Latgé, and S. Paris, Infect. Immun. 62:4380-4388, 1994). The RODB gene was cloned and disrupted. RodBp was highly homologous to RodAp and different from DewAp of A. nidulans. ΔrodB conidia had a rodlet layer similar to that of the wild-type conidia. Therefore, unlike RodAp, RodBp is not required for rodlet formation. The surface of ΔrodA conidia is granular; in contrast, an amorphous layer is present at the surface of the conidia of the ΔrodA ΔrodB double mutant. These data show that RodBp plays a role in the structure of the conidial cell wall. Moreover, rodletless mutants are more sensitive to killing by alveolar macrophages, suggesting that RodAp or the rodlet structure is involved in the resistance to host cells. PMID:12620846

Flexible pavement rehabilitation using pulverization.

DOT National Transportation Integrated Search

2008-06-01

Pulverization is a roadway rehabilitation strategy that involves in-place recycling of the entire existing flexible pavement layer and some of the existing granular base layer (Figure 1). Pavement pulverization provides an alternative to conventional...

Fast voltage-sensitive dye imaging of excitatory and inhibitory synaptic transmission in the rat granular retrosplenial cortex.

PubMed

Nixima, Ken'ichi; Okanoya, Kazuo; Ichinohe, Noritaka; Kurotani, Tohru

2017-09-01

Rodent granular retrosplenial cortex (GRS) has dense connections between the anterior thalamic nuclei (ATN) and hippocampal formation. GRS superficial pyramidal neurons exhibit distinctive late spiking (LS) firing property and form patchy clusters with prominent apical dendritic bundles. The aim of this study was to investigate spatiotemporal dynamics of signal transduction in the GRS induced by ATN afferent stimulation by using fast voltage-sensitive dye imaging in rat brain slices. In coronal slices, layer 1a stimulation, which presumably activated thalamic fibers, evoked propagation of excitatory synaptic signals from layers 2-4 to layers 5-6 in a direction perpendicular to the layer axis, followed by transverse signal propagation within each layer. In the presence of ionotropic glutamate receptor antagonists, inhibitory responses were observed in superficial layers, induced by direct activation of inhibitory interneurons in layer 1. In horizontal slices, excitatory signals in deep layers propagated transversely mainly from posterior to anterior via superficial layers. Cortical inhibitory responses upon layer 1a stimulation in horizontal slices were weaker than those in the coronal slices. Observed differences between coronal and horizontal planes suggest anisotropy of the intracortical circuitry. In conclusion, ATN inputs are processed differently in coronal and horizontal planes of the GRS and then conveyed to other cortical areas. In both planes, GRS superficial layers play an important role in signal propagation, which suggests that superficial neuronal cascade is crucial in the integration of multiple information sources. NEW & NOTEWORTHY Superficial neurons in the rat granular retrosplenial cortex (GRS) show distinctive late-spiking (LS) firing property. However, little is known about spatiotemporal dynamics of signal transduction in the GRS. We demonstrated LS neuron network relaying thalamic inputs to deep layers and anisotropic distribution of inhibition between coronal and horizontal planes. Since deep layers of the GRS receive inputs from the subiculum, GRS circuits may work as an integrator of multiple sources such as sensory and memory information. Copyright © 2017 the American Physiological Society.

The Harderian gland, its secretory duct and porphyrin content in the mongolian gerbil (Meriones unguiculatus).

PubMed Central

Johnston, H S; McGadey, J; Thompson, G G; Moore, M R; Payne, A P

1983-01-01

The Harderian gland, its secretory duct and porphyrin content were examined in the mongolian gerbil (Meriones unguiculatus). The gland consisted of tubules lined by a single layer of epithelial cells and a myoepithelial network. The tubule cells were often binucleate and possessed lipid vacuoles in the apical half of the cell, a corona of granular endoplasmic reticulum surrounding the nucleus, and cytoplasmic 'slashes'. The latter are probably derived from dense membranous couplets and may be precursors of the lipid vacuoles. Holocrine and merocrine secretion was observed. Interstitial cells included plasma cells, mast cells and (predominantly) melanocytes which render the gland black. The gland was surrounded by a collagen capsule and an outer layer of highly attenuated (possibly endothelioid) cells. Within the gland, the secretory duct was lined by a single layer of normal tubule cells. Outside the gland, the duct enlarged to form an ampulla, from which clefts led off to deep crypts. The ampulla and clefts were lined by cells with small dense apical granules and stubby microvilli; some possessed lipid vacuoles. The crypts were lined by serous cells with active Golgi regions. At the duct opening, ampullary cells became squamous and goblet cells occurred. Geometric crystalloid deposits (with a layered structure of 7.6 nm periodicity) occurred at cleft-crypt junctions. Islets of extra-glandular ductal tissue were occasionally found within the gland. Porphyrins were detectable both by chemical assay and fluorescence microscopy. There was a trend for female glands to have a higher content than males. Solid intraluminal accretions of porphyrin and/or lipid were present. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 7 Fig. 8 Fig. 9 Fig. 10 Fig. 12 Fig. 13 Fig. 14 Fig. 15 Fig. 16 PMID:6654750

Efficiency of a multi-soil-layering system on wastewater treatment using environment-friendly filter materials.

PubMed

Ho, Chia-Chun; Wang, Pei-Hao

2015-03-23

The multi-soil-layering (MSL) system primarily comprises two parts, specifically, the soil mixture layer (SML) and the permeable layer (PL). In Japan, zeolite is typically used as the permeable layer material. In the present study, zeolite was substituted with comparatively cheaper and more environmentally friendly materials, such as expanded clay aggregates, oyster shells, and already-used granular activated carbon collected from water purification plants. A series of indoor tests indicated that the suspended solid (SS) removal efficiency of granular activated carbon was between 76.2% and 94.6%; zeolite and expanded clay aggregates achieved similar efficiencies that were between 53.7% and 87.4%, and oyster shells presented the lowest efficiency that was between 29.8% and 61.8%. Further results show that the oyster shell system required an increase of wastewater retention time by 2 to 4 times that of the zeolite system to maintain similar chemical oxygen demand (COD) removal efficiency. Among the four MSL samples, the zeolite system and granular activated carbon system demonstrated a stable NH3-N removal performance at 92.3%-99.8%. The expanded clay aggregate system present lower removal performance because of its low adsorption capacity and excessively large pores, causing NO3--N to be leached away under high hydraulic loading rate conditions. The total phosphorous (TP) removal efficiency of the MSL systems demonstrated no direct correlation with the permeable layer material. Therefore, all MSL samples achieved a TP efficiency of between 92.1% and 99.2%.

Modification of the structural and magnetic properties of granular FePt films by seed layer conditioning

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wicht, S., E-mail: s.wicht@ifw-dresden.de; TU Dresden, Institut für Werkstoffwissenschaft, Helmholtzstraße 10, D-01069 Dresden; Neu, V.

2015-01-07

The steadily increasing amount of digital information necessitates the availability of reliable high capacity magnetic data storage. Here, future hard disk drives with extended areal storage densities beyond 1.0 Tb/in{sup 2} are envisioned by using high anisotropy granular and chemically L1{sub 0}-ordered FePt (002) perpendicular media within a heat-assisted magnetic recording scheme. Perpendicular texturing of the [001] easy axes of the individual grains can be achieved by using MgO seed layers. It is therefore investigated, if and how an Ar{sup +} ion irradiation of the MgO seed layer prior to the deposition of the magnetic material influences the MgO surfacemore » properties and hereby the FePt [001] texture. Structural investigations reveal a flattening of the seed layer surface accompanied by a change in the morphology of the FePt grains. Moreover, the fraction of small second layer particles and the degree of coalescence of the primarily deposited FePt grains strongly increases. As for the magnetic performance, this results in a reduced coercivity along the magnetic easy axis (out of plane) and in enhanced hard axis (in-plane) remanence values. The irradiation induced changes in the magnetic properties of the granular FePt-C films are traced back to the accordingly modified atomic structure of the FePt-MgO interface region.« less

Proximity effect in superconducting-ferromagnetic granular structures

NASA Astrophysics Data System (ADS)

Greener, Hadar; Shelukhin, Victor; Karpovski, Michael; Goldstein, Moshe; Palevski, Alexander

2018-01-01

We examined the proximity effect in granular films made of Pb, a superconductor, and Ni, a ferromagnet, with various compositions. Slow decay of the critical temperature as a function of the relative volume concentration of Ni per sample was demonstrated by our measurements, followed by a saturation of Tc. Using an approximate theoretical description of our granular system in terms of a layered one, we show that our data can only be reasonably fitted by a trilayer model. This indicates the importance of the interplay between different ferromagnetic grains, which should lead to triplet Cooper pairing.

Spreading granular material with a blade

NASA Astrophysics Data System (ADS)

Dressaire, Emilie; Singh, Vachitar; Grimaldi, Emma; Sauret, Alban

2015-11-01

The spreading of a complex fluid with a blade is encountered in applications that range from the bulldozing of granular material in construction projects to the coating of substrates with fluids in industrial applications. This spreading process is also present in everyday life, when we use a knife to turn a lump of peanut butter into a thin layer over our morning toast. In this study, we rely on granular media in a model experiment to describe the three-dimensional spreading of the material. Our experimental set-up allows tracking the spreading of a sandpile on a translating flat surface as the blade remains fixed. We characterize the spreading dynamics and the shape of the spread fluid layer when varying the tilt of the blade, its spacing with the surface and its speed. Our findings suggest that it is possible to tune the spreading parameters to optimize the coating.

Mesoscopic Length Scale Controls the Rheology of Dense Suspensions

NASA Astrophysics Data System (ADS)

Bonnoit, Claire; Lanuza, Jose; Lindner, Anke; Clement, Eric

2010-09-01

From the flow properties of dense granular suspensions on an inclined plane, we identify a mesoscopic length scale strongly increasing with volume fraction. When the flowing layer height is larger than this length scale, a diverging Newtonian viscosity is determined. However, when the flowing layer height drops below this scale, we evidence a nonlocal effective viscosity, decreasing as a power law of the flow height. We establish a scaling relation between this mesoscopic length scale and the suspension viscosity. These results support recent theoretical and numerical results implying collective and clustered granular motion when the jamming point is approached from below.

Mesoscopic length scale controls the rheology of dense suspensions.

PubMed

Bonnoit, Claire; Lanuza, Jose; Lindner, Anke; Clement, Eric

2010-09-03

From the flow properties of dense granular suspensions on an inclined plane, we identify a mesoscopic length scale strongly increasing with volume fraction. When the flowing layer height is larger than this length scale, a diverging Newtonian viscosity is determined. However, when the flowing layer height drops below this scale, we evidence a nonlocal effective viscosity, decreasing as a power law of the flow height. We establish a scaling relation between this mesoscopic length scale and the suspension viscosity. These results support recent theoretical and numerical results implying collective and clustered granular motion when the jamming point is approached from below.

Granular cell myoblastoma of the oesophagus

PubMed Central

Larsen, Gordon L.; Armstrong, Raymond G.; Stanford, William; Cline, Robert E.

1973-01-01

Larsen, G. L., Armstrong, R. G., Stanford, W., and Cline, R. E. (1973).Thorax, 28, 641-643. Granular cell myoblastoma of the oesophagus. During evaluation of symptoms of oesophageal reflux in a 40-year-old man, a filling defect of the distal oesophagus was seen on the oesophagogram, and this was noted to be a submucosal mass at oesophagoscopy. He also had an oesophageal hiatus hernia. The lesion proved to be a granular cell myoblastoma, a rarity in the oesophagus, only 11 previous cases having been reported. Symptomatology evaluation and management of granular cell myoblastoma of the oesophagus are discussed. As with other submucosal lesions of the oesophagus, preoperative biopsy through an intact mucosa is to be avoided because of danger to the patient from haemorrhage or perforation and subsequent inflammatory reaction making surgical resection and microscopic diagnosis difficult. Images PMID:4361526

Feasibility analysis of base compaction specification : [project brief].

DOT National Transportation Integrated Search

2013-02-01

Appropriate design and construction of the aggregate base layer has significant influence on : structural stability and performance of pavements. Controlling the construction quality of : the granular base layer is important to achieve long-lasting p...

Granular flows in constrained geometries

NASA Astrophysics Data System (ADS)

Murthy, Tejas; Viswanathan, Koushik

Confined geometries are widespread in granular processing applications. The deformation and flow fields in such a geometry, with non-trivial boundary conditions, determine the resultant mechanical properties of the material (local porosity, density, residual stresses etc.). We present experimental studies of deformation and plastic flow of a prototypical granular medium in different nontrivial geometries- flat-punch compression, Couette-shear flow and a rigid body sliding past a granular half-space. These geometries represent simplified scaled-down versions of common industrial configurations such as compaction and dredging. The corresponding granular flows show a rich variety of flow features, representing the entire gamut of material types, from elastic solids (beam buckling) to fluids (vortex-formation, boundary layers) and even plastically deforming metals (dead material zone, pile-up). The effect of changing particle-level properties (e.g., shape, size, density) on the observed flows is also explicitly demonstrated. Non-smooth contact dynamics particle simulations are shown to reproduce some of the observed flow features quantitatively. These results showcase some central challenges facing continuum-scale constitutive theories for dynamic granular flows.

A model experiment of liquefaction and fluid transport: quantifying the effect of permeability discontinuity

NASA Astrophysics Data System (ADS)

Yasuda, N.; Sumita, I.

2013-12-01

Model experiments of liquefaction of a water-saturated sand (quick sand) is commonly conducted in class and in public. Various phenomena caused by liquefaction are reproduced within a closed bottle containing push-pins (Nohguchi, 2004). Experiments for tilted and layered case have also been conducted (Peacock, 2006). However quantitative measurements of liquid transport in these experiments have rarely been made. Here we show that such measurements are possible by analyzing the video images taken during such experiments. In addition, we show that a simple physical model is capable of explaining the time scales needed to expel the interstitial liquid. An experimental cell (cross section 22.0 mm x 99.4 mm, height 107.6 mm) is filled with a granular matter and water. The lower 33.0 mm consists of a two-layered granular medium, the upper layer consists of fine particles and the lower layer consists of coarse particles, with particle sizes of 0.05 mm and 0.2 mm, respectively. Since permeability depends on the square of the particle size, the upper layer becomes a low-permeability layer. We liquefy the cell by an impulsive vibration and study how the liquid migrates afterwards. We also vary the particle size combinations (upper layer: 0.05-0.15 mm, lower layer: 0.15-0.6 mm) and the thickness ratio of the 2 layers, and study how the time scale of the liquid migration depends on these changeable parameters. In a two-layered medium, we find that the pore water which originated from the bottom layer temporary accumulates at the interface of the two layers, and then ascends through the upper layer in the form of horizontal sheet or vertical channels. We find that these two different discharge styles are controlled by the permeability ratio of the two layers. We study the temporal change of the thicknesses of the two layers and find that there are three stages; 1: the slope of the upper surface is leveled by the impulse, 2: the pore water is discharged from the bottom layer and accumulates at the interface, after which it migrates upwards, 3: water discharge ends, and particles settle. We measured the relaxation time needed for the discharge and compaction to end. Because low-permeability layer inhibits pore water from rising, longer time is needed for a two-layer case compared to the one-layer case. When the particle size of the upper layer is about 1/3 or smaller than that of the lower layer, relaxation time becomes independent of the bottom particle size. We modeled the relaxation time by introducing the effective permeability of two-layered medium, and find that it explains the measurements well. References Nohguchi, Y., 2004, ICTAM04 Proceedings, Warsaw, Poland. Peacock, D. C. P., 2006, J. Geosci.Ed, 54, 550

Light and electron microscopic observations on the organization of skin and associated glands of two caecilian amphibians from Western Ghats of India.

PubMed

Damodaran, Arun; Reston Saroja, Beyo; Kotharambath, Ramachandran; Mohammad Abdulkader, Akbarsha; Oommen, Oommen V; Lekha, Divya

2018-03-01

We adopted light and electron microscopy to understand the structure of the skin of two species of caecilians, Ichthyophis tricolor and Uraeotyphlus cf. oxyurus, from Western Ghats of Kerala, India. The surface of the skin of these caecilians contains an irregular pattern of microridges. Oval, round and polymorphic glandular openings are randomly distributed all over the skin surface. Most of the openings are funnel shaped. The epithelial cells along the rim of the opening descend into the tunnel of the duct. A few glandular openings protrude slightly above the epithelium of the duct. The skin is formed of epidermis and dermis. Small flat disk-like dermal scales, composed of a basal plate of several layers of unmineralized collagen fibers topped with a discontinuous layer of mineralized globular squamulae, are lodged in pouches in the transverse ridges of the skin. Each pouch contains 1-4 scales, which might differ in size. The scales are almost similar between species, yet the difference can be useful in distinguishing between the two species. Flask cells and Merkel cells are present in the epidermis. Two types of glands, mucous and granular, are present in the dermis. The mucous glands are densely packed with mucous vesicles. Darkly stained mucous producing cells are located around the periphery of the gland. Secretory mucous vesicles differ in their organization and distribution. The granular glands are located perpendicular to the skin surface. The granule producing cells of the gland are located near the periphery. There are differently stained spherical secretory granules of various sizes in the cytoplasm. Thus, the use of different microscopic techniques contributed fascinatingly to the first ever understanding of organization of the skin of two selected caecilian species from Western Ghats, revealing certain features to differ between them. Copyright © 2018 Elsevier Ltd. All rights reserved.

Micro-scale investigation on the quasi-static behavior of granular material

NASA Astrophysics Data System (ADS)

Li, Xia

Granular material exhibits complex responses when subjected to various external loading. Fundamental mechanisms have not been well established so far, including that about the critical state, one of the most important concepts in the modern soil mechanics. With the recognition that granular material is discrete in nature, the basic understanding can only be obtained from the particle scale. The complexity in granular material behavior lies in the fact that the macroscopic behavior of granular material is determined by not only the interactions operating at contacts, but also how the particles become arranged in space to form an internal structure. This research is aimed to microscopically investigate the influence of the internal structure and the fundamental mechanism about the critical state. In view of the extensive laboratory test data already available in the literature, a numerical simulation method, DEM, is employed as the tool to conduct particle-scale investigations. The contact model for two in-contact circular disks is derived theoretically from the elasticity theory, and the result is a linear contact model with constant stiffness and lateral sliding. Based on the contact model, a systematic series of numerical tests has been implemented, and the results can successfully reproduce the main characteristics in the behavior of natural granular material, under various loading conditions. The macro-micro relationship is the link between the investigations at the two worlds. The key point is to describe the internal structure with the two dual cell systems, a particle cell system and a void cell system. Based on these two systems, the stress and strain in a uniform field are equivalently expressed in terms of the contact forces/relative displacements, and the micro-geometrical variables. With the microstructural definition of the stress tensor, the stress state of granular material is studied microscopically. The stress-fabric-force relation is derived, based on the variables describing the statistics of the contact forces and the contact vectors. By studying the evolution of the micro-quantities during shearing, how the internal structure affects the macro stress state under different loading condition is revealed. With the assumption that the influence of the local variance in stress is ignorable, the response of granular material can be investigated based on the void cell system. Starting from the behavior of a single void cell, the evolutions of the internal structure and its influence on the response of granular material are explained. The stress ratio and the dilatancy behavior of granular material are investigated. The influences of the void ratio, the mean normal stress and the drainage condition are discussed. The fundamental mechanism of the critical state is studied in the framework of thermodynamics with properly considering the influence of the internal structure. The normalized stress ratio tensor at critical state is associated with the critical void cell anisotropy, corresponding to the maximal energy dissipation. The (e, p) relationship at critical state is associated with the critical combination of the void cell size and the contact interactions, corresponding to the minimal free energy. The investigation on the influence of the internal structure anisotropy on the granular material behavior and the critical state is carried out. The results show that at small strain levels, the behavior of granular material is mainly affected by the initial fabric. As shearing continuous, the internal structure of granular material is gradually changed. The granular material approaches the critical state, which is irrespective with the initial internal structure. The critical state of granular material is not unique. With different loading modes, the critical state of granular material, including both the critical stress ratio and the critical (e, p) relations, are found to be different. A fabric tensor is defined based on the characteristics of the void cells. The laboratory method to quantify the fabric anisotropy is proposed by deviatoric shearing. 3D numerical simulations have been carried out to investigate the influence of the loading mode, which is found to be an important factor in the large strain behavior of granular material. With the obtained microscopic understanding, the influence of contact model on granular material behavior is investigated. A method to quantify the fabric anisotropy is proposed. And a simple discussion on the state variable used in the elasto-plastic constitutive model is given.

Heterogeneity of murine adherent interleukin-2-activated killer cells. Differential effect of prostaglandin E2 and forskolin.

PubMed

Vaillier, D; Daculsi, R; Gualde, N

1995-01-01

We have studied the relationship between cytotoxic activity, size and granularity of murine interleukin-2-activated adherent killer cells issued from spleen cells cultured with high levels of IL-2. The effects of prostaglandin E2 (PGE2) and forskolin upon these cells were assessed. All adherent spleen cells obtained after 5 days of culture were large granular lymphocytes but presented a heterogeneity in size and granularity. After fractionation on a discontinuous-density Percoll gradient, four cellular subpopulations were isolated. Fluorescence-activated cell sorting analysis showed that cells of the lightest fraction (F1) were the largest, while the cells found in the heaviest fraction (F4) were much more granular than the cells collected in the two intermediate fractions (F2 and F3). The serine esterases level was higher in F4 than in unfractionated cells and diminished to about 40% in cells of fractions F2 and F3, which expressed a cytotoxic activity against YAC-1 cells higher than that in unfractionated cells or in F1 or F4, which presented the lowest cytotoxic activity. When AK cells were cultured for 48 h in the presence of either PGE2 or forskolin, which induce an intracellular increase of cAMP, we observed that PGE2 (1 microM) inhibited the cytotoxic activity, but surprisingly forskolin (2 microM) exerted a stimulating effect on the induction of cytotoxic activity. After fractionation on a discontinuous Percoll gradient we observed the same cellular distribution among PGE2 or forskolin-treated or -untreated cells, but PGE2 induced an increase of size and granularity. This effect of PGE2 was more potent on the cells collected in F4. However this variation of granularity was not associated with any variation in the serine esterase level. The cytotoxic activity of PGE2- or forskolin-treated cells did not present any significant variation relative to the control for cells collected in F2 and F3; on the other hand, forskolin-treated cells collected in F4 showed a significantly higher cytotoxicity than did the corresponding untreated or PGE2-treated cells.

A comprehensive study of MPI parallelism in three-dimensional discrete element method (DEM) simulation of complex-shaped granular particles

NASA Astrophysics Data System (ADS)

Yan, Beichuan; Regueiro, Richard A.

2018-02-01

A three-dimensional (3D) DEM code for simulating complex-shaped granular particles is parallelized using message-passing interface (MPI). The concepts of link-block, ghost/border layer, and migration layer are put forward for design of the parallel algorithm, and theoretical scalability function of 3-D DEM scalability and memory usage is derived. Many performance-critical implementation details are managed optimally to achieve high performance and scalability, such as: minimizing communication overhead, maintaining dynamic load balance, handling particle migrations across block borders, transmitting C++ dynamic objects of particles between MPI processes efficiently, eliminating redundant contact information between adjacent MPI processes. The code executes on multiple US Department of Defense (DoD) supercomputers and tests up to 2048 compute nodes for simulating 10 million three-axis ellipsoidal particles. Performance analyses of the code including speedup, efficiency, scalability, and granularity across five orders of magnitude of simulation scale (number of particles) are provided, and they demonstrate high speedup and excellent scalability. It is also discovered that communication time is a decreasing function of the number of compute nodes in strong scaling measurements. The code's capability of simulating a large number of complex-shaped particles on modern supercomputers will be of value in both laboratory studies on micromechanical properties of granular materials and many realistic engineering applications involving granular materials.

Age-dependent differences in myelin basic protein expression in the hippocampus of young, adult and aged gerbils

PubMed Central

Ahn, Ji Hyeon; Lee, Tae-Kyeong; Park, Joon Ha; Cho, Jeong Hwi; Kim, In Hye; Lee, Jae Chul; Hong, Seongkweon; Jeon, Yong Hwan; Kang, Il Jun; Lee, Young Joo

2017-01-01

Myelin degeneration is one of the characteristics of aging and degenerative diseases. This study investigated age-related alterations in expression of myelin basic protein (MBP) in the hippocampal subregions (dentate gyrus, CA2/3 and CA1 areas) of gerbils of various ages; young (1 month), adult (6 months) and aged (24 months), using western blot and immunohistochemistry. Western blot results showed tendencies of age-related reductions of MBP levels. MBP immunoreactivity was significantly decreased with age in synaptic sites of trisynaptic loops, perforant paths, mossy fibers, and Schaffer collaterals. In particular, MBP immunoreactive fibers in the dentate molecular cell layer (perforant path) was significantly reduced in adult and aged subjects. In addition, MBP immunoreactive mossy fibers in the dentate polymorphic layer and in the CA3 striatum radiatum was significantly decreased in the aged group. Furthermore, we observed similar age-related alterations in the CA1 stratum radiatum (Schaffer collaterals). However, the density of MBP immunoreactive fibers in the dentate granular cell layer and CA stratum pyramidale was decreased with aging. These findings indicate that expression of MBP is age-dependent and tissue specific according to hippocampal layers. PMID:29046699

Three layers multi-granularity OCDM switching system based on learning-stateful PCE

NASA Astrophysics Data System (ADS)

Wang, Yubao; Liu, Yanfei; Sun, Hao

2017-10-01

In the existing three layers multi-granularity OCDM switching system (TLMG-OCDMSS), F-LSP, L-LSP and OC-LSP can be bundled as switching granularity. For CPU-intensive network, the node not only needs to compute the path but also needs to bundle the switching granularity so that the load of single node is heavy. The node will paralyze when the traffic of the node is too heavy, which will impact the performance of the whole network seriously. The introduction of stateful PCE(S-PCE) will effectively solve these problems. PCE is composed of two parts, namely, the path computation element and the database (TED and LSPDB), and returns the result of path computation to PCC (path computation clients) after PCC sends the path computation request to it. In this way, the pressure of the distributed path computation in each node is reduced. In this paper, we propose the concept of Learning PCE (L-PCE), which uses the existing LSPDB as the data source of PCE's learning. By this means, we can simplify the path computation and reduce the network delay, as a result, improving the performance of network.

Molecular layer interneurons of the cerebellum: developmental and morphological aspects.

PubMed

Sotelo, Constantino

2015-10-01

During the past 25 years, our knowledge on the development of basket and stellate cells (molecular layer interneurons [MLIs]) has completely changed, not only regarding their origin from the ventricular zone, corresponding to the primitive cerebellar neuroepithelium, instead of the external granular layer, but above all by providing an almost complete account of the genetic regulations (transcription factors and other genes) involved in their differentiation and synaptogenesis. Moreover, it has been shown that MLIs' precursors (dividing neuroblasts) and not young postmitotic neurons, as in other germinal neuroepithelia, leave the germinative zone and migrate all along a complex and lengthy path throughout the presumptive cerebellar white matter, which provides suitable niches exerting epigenetic influences on their ultimate neuronal identities. Recent studies carried out on the anatomical-functional properties of adult MLIs emphasize the importance of these interneurons in regulating PC inhibition, and point out the crucial role played by electrical synaptic transmission between MLIs as well as ephaptic interactions between them and Purkinje cells at the pinceaux level, in the regulation of this inhibition.

Neuroglian-positive plasmatocytes of Manduca sexta and the initiation of hemocyte attachment to foreign surfaces.

PubMed

Nardi, James B; Pilas, Barbara; Bee, Charles Mark; Zhuang, Shufei; Garsha, Karl; Kanost, Michael R

2006-01-01

Observations of hemocyte aggregation on abiotic surfaces suggested that certain plasmatocytes from larvae of Manduca sexta act as foci for hemocyte aggregation. To establish how these particular plasmatocytes form initial attachments to foreign surfaces, they were cultured separately from other selected populations of hemocytes. While all circulating plasmatocytes immunolabel with anti-beta-integrin monoclonal antibody (MAb), only these larger plasmatocytes immunolabel with a MAb to the adhesion protein neuroglian. Neuroglian-negative plasmatocytes and granular cells that have been magnetically segregated from the majority of granular cells adhere to each other but fail to adhere to foreign substrata; by contrast, neuroglian-positive plasmatocytes that segregate with most granular cells adhere firmly to a substratum. Hemocytes form stable aggregates around the large, neuroglian-positive plasmatocytes. However, if neuroglian-positive plasmatocytes are separated from most granular cells, attachment of these plasmatocytes to foreign surfaces is suppressed.

Destabilization of confined granular packings due to fluid flow

NASA Astrophysics Data System (ADS)

Monloubou, Martin; Sandnes, Bjørnar

2016-04-01

Fluid flow through granular materials can cause fluidization when fluid drag exceeds the frictional stress within the packing. Fluid driven failure of granular packings is observed in both natural and engineered settings, e.g. soil liquefaction and flowback of proppants during hydraulic fracturing operations. We study experimentally the destabilization and flow of an unconsolidated granular packing subjected to a point source fluid withdrawal using a model system consisting of a vertical Hele-Shaw cell containing a water-grain mixture. The fluid is withdrawn from the cell at a constant rate, and the emerging flow patterns are imaged in time-lapse mode. Using Particle Image Velocimetry (PIV), we show that the granular flow gets localized in a narrow channel down the center of the cell, and adopts a Gaussian velocity profile similar to those observed in dry grain flows in silos. We investigate the effects of the experimental parameters (flow rate, grain size, grain shape, fluid viscosity) on the packing destabilization, and identify the physical mechanisms responsible for the observed complex flow behaviour.

Single-Trial Analysis of V1 Responses Suggests Two Transmission States

NASA Technical Reports Server (NTRS)

Shah, A. S.; Knuth, K. H.; Truccolo, W. A.; Mehta, A. D.; McGinnis, T.; OConnell, N.; Ding, M.; Bressler, S. L.; Schroeder, C. E.

2002-01-01

Sensory processing in the visual, auditory, and somatosensory systems is often studied by recording electrical activity in response to a stimulus of interest. Typically, multiple trial responses to the stimulus are averaged to isolate the stereotypic response from noise. However, averaging ignores dynamic variability in the neuronal response, which is potentially critical to understanding stimulus-processing schemes. Thus, we developed the multiple component, Event-Related Potential (mcERP) model. This model asserts that multiple components, defined as stereotypic waveforms, comprise the stimulus-evoked response and that these components may vary in amplitude and latency from trial to trial. Application of this model to data recorded simultaneously from all six laminae of V1 in an awake, behaving monkey performing a visual discrimination yielded three components. The first component localized to granular V1, the second was located in supragranular V1, and the final component displayed a multi-laminar distribution. These modeling results, which take into account single-trial response dynamics, illustrated that the initial activation of VI occurs in the granular layer followed by activation in the supragranular layers. This finding is expected because the average response in those layers demonstrates the same progression and because anatomical evidence suggests that the feedforward input in V1 enters the granular layer and progresses to supragranular layers. In addition to these findings, the granular component of the model displayed several interesting trial-to-trial characteristics including (1) a bimodal latency distribution, (2) a latency-related variation in response amplitude, (3) a latency correlation with the supragranular component, and (4) an amplitude and latency association with the multi-laminar component. Direct analyses of the single-trial data were consistent with these model predictions. These findings suggest that V1 has at least 2 transmission states, which may be modulated by various effects such as attention, dynamics in local EEG rhythm, or variation in sensory inputs.

Pathological findings in retina and visual pathways associated to natural Scrapie in sheep.

PubMed

Hortells, Paloma; Monzón, Marta; Monleón, Eva; Acín, Cristina; Vargas, Antonia; Bolea, Rosa; Luján, Lluís; Badiola, Juan José

2006-09-07

This work represents a comprehensive pathological description of the retina and visual pathways in naturally affected Scrapie sheep. Twenty naturally affected Scrapie sheep and 6 matched controls were used. Eyes, optic nerves and brain from each animal were fixed and histologically processed using hematoxylin-eosin, followed by immunohistochemical staining for prion protein (PrPsc) and glial fibrillar acidic protein (GFAP). Retinal histopathological changes were observed in only 7 clinically affected animals and mainly consisted of loss of outer limitant layer definition, outer plexiform layer atrophy, disorganization and loss of nuclei in both nuclear layers, and Müller glia hypertrophy. PrPsc was detected in the retina of 19 of the 20 sheep and characterized by a disseminated granular deposit across layers and intraneuronally in ganglion cells. The inner plexiform and the ganglion cell layers were the structures most severely affected by PrPsc deposits. PrPsc exhibited a tendency to spread from these two layers to the others. A marked increase in the number and intensity of GFAP-expressing Müller cells was observed in the clinical stage, especially at the terminal stage of the disease. Spongiosis and PrPsc were detected within the visual pathways at the preclinical stage, their values increasing during the course of the disease but varying between the areas examined. PrPsc was detected in only 3 optic nerves. The results suggest that the presence of PrPsc in the retina correlates with disease progression during the preclinical and clinical stages, perhaps using the inner plexiform layer as a first entry site and diffusing from the brain using a centrifugal model.

Simulation of nanopowder compaction in terms of granular dynamics

NASA Astrophysics Data System (ADS)

Boltachev, G. Sh.; Volkov, N. B.

2011-07-01

The uniaxial compaction of nanopowders is simulated using the granular dynamics in the 2D geometry. The initial arrangement of particles is represented by (i) a layer of particles executing Brownian motion (isotropic structures) and (ii) particles falling in the gravity field (anisotropic structures). The influence of size effects and the size of a model cell on the properties of the structures are studied. The compaction of the model cell is simulated with regard to Hertz elastic forces between particles, Cattaneo-Mindlin-Deresiewicz shear friction forces, and van der Waals-Hamaker dispersion forces of attraction. Computation is performed for monodisperse powders with particle sizes ranging from 10 to 400 nm and for "cohesionless" powder, in which attractive forces are absent. It is shown that taking into account dispersion forces makes it possible to simulate the size effect in the nanopowder compaction: the compressibility of the nanopowder drops as the particles get finer. The mean coordination number and the axial and lateral pressures in the powder systems are found, and the effect of the density and isotropy of the initial structure on the compressibility is analyzed. The applicability of well-known Rumpf's formula for the size effect is discussed.

Shocks in oscillated granular layers

NASA Astrophysics Data System (ADS)

Bougie, J.; Moon, Sung Joon; Swift, J. B.; Swinney, Harry L.

2001-11-01

We study shock formation in vertically oscillated granular layers, where shock waves form with each collision between the layer and the bottom plate of the container. We use both three-dimensional numerical solutions of continuum equations developed by Jenkins and Richman (J.T. Jenkins and M.W. Richman, Arch. Rat. Mech. Anal. 87), 355 (1985) for smooth and nearly elastic hard spheres, and previously validated molecular dynamics (MD) simulations (C. Bizon, M.D. Shattuck, J.B. Swift, W.D. McCormick, and H.L. Swinney, Phys. Rev. Lett. 80), 57 (1998). Both methods capture the shock formation, and the two methods agree quantitatively for small dissipation. We also investigate the effect of inelasticity on shock formation, and use both smooth and rough hard-sphere MD simulations to investigate the effect of friction in this system.

Preparation and transport properties of superconducting layers in the Ca-Sr-Bi-Cu-O system

NASA Astrophysics Data System (ADS)

Klee, M.; Stollman, G. M.; Stotz, S.; de Vries, J. W. C.

1988-08-01

Superconducting layers in the CaSrBiCuO system are prepared by thermal decomposition of metal carboxylates using a spin-coating and a dip-coating method onto ceramic MgO substrates. The samples consist of a tetragonal calcium-strontium-bismuth-cuprate and two bismuth-free calcium-strontium-cuprates. A step in the resistance versus temperature curve is observed which, together with the influence of magnetic fields, is interpreted as typical for a granular superconductor. The analysis shows that the critical current density is determined by domains of the order of some unit cells. The strong dependence of the superconducting transition on the orientation of an applied magnetic field is probably caused by the anisotropic layer structure. The coherence length perpendicular to the c-axis of the material is estimated to be ξab(0) = 4.0 nm and parallel to the c-axis ξc(0) = 0.6 nm.

Efficiency of a Multi-Soil-Layering System on Wastewater Treatment Using Environment-Friendly Filter Materials

PubMed Central

Ho, Chia-Chun; Wang, Pei-Hao

2015-01-01

The multi-soil-layering (MSL) system primarily comprises two parts, specifically, the soil mixture layer (SML) and the permeable layer (PL). In Japan, zeolite is typically used as the permeable layer material. In the present study, zeolite was substituted with comparatively cheaper and more environmentally friendly materials, such as expanded clay aggregates, oyster shells, and already-used granular activated carbon collected from water purification plants. A series of indoor tests indicated that the suspended solid (SS) removal efficiency of granular activated carbon was between 76.2% and 94.6%; zeolite and expanded clay aggregates achieved similar efficiencies that were between 53.7% and 87.4%, and oyster shells presented the lowest efficiency that was between 29.8% and 61.8%. Further results show that the oyster shell system required an increase of wastewater retention time by 2 to 4 times that of the zeolite system to maintain similar chemical oxygen demand (COD) removal efficiency. Among the four MSL samples, the zeolite system and granular activated carbon system demonstrated a stable NH3-N removal performance at 92.3%–99.8%. The expanded clay aggregate system present lower removal performance because of its low adsorption capacity and excessively large pores, causing NO3−-N to be leached away under high hydraulic loading rate conditions. The total phosphorous (TP) removal efficiency of the MSL systems demonstrated no direct correlation with the permeable layer material. Therefore, all MSL samples achieved a TP efficiency of between 92.1% and 99.2%. PMID:25809517

Shear flow of dense granular materials near smooth walls. I. Shear localization and constitutive laws in the boundary region.

PubMed

Shojaaee, Zahra; Roux, Jean-Noël; Chevoir, François; Wolf, Dietrich E

2012-07-01

We report on a numerical study of the shear flow of a simple two-dimensional model of a granular material under controlled normal stress between two parallel smooth frictional walls moving with opposite velocities ± V. Discrete simulations, which are carried out with the contact dynamics method in dense assemblies of disks, reveal that, unlike rough walls made of strands of particles, smooth ones can lead to shear strain localization in the boundary layer. Specifically, we observe, for decreasing V, first a fluidlike regime (A), in which the whole granular layer is sheared, with a homogeneous strain rate except near the walls, then (B) a symmetric velocity profile with a solid block in the middle and strain localized near the walls, and finally (C) a state with broken symmetry in which the shear rate is confined to one boundary layer, while the bulk of the material moves together with the opposite wall. Both transitions are independent of system size and occur for specific values of V. Transient times are discussed. We show that the first transition, between regimes A and B, can be deduced from constitutive laws identified for the bulk material and the boundary layer, while the second one could be associated with an instability in the behavior of the boundary layer. The boundary zone constitutive law, however, is observed to depend on the state of the bulk material nearby.

Development of a double-layered ceramic filter for aerosol filtration at high-temperatures: the filter collection efficiency.

PubMed

de Freitas, Normanda L; Gonçalves, José A S; Innocentini, Murilo D M; Coury, José R

2006-08-25

The performance of double-layered ceramic filters for aerosol filtration at high temperatures was evaluated in this work. The filtering structure was composed of two layers: a thin granular membrane deposited on a reticulate ceramic support of high porosity. The goal was to minimize the high pressure drop inherent of granular structures, without decreasing their high collection efficiency for small particles. The reticulate support was developed using the technique of ceramic replication of polyurethane foam substrates of 45 and 75 pores per inch (ppi). The filtering membrane was prepared by depositing a thin layer of granular alumina-clay paste on one face of the support. Filters had their permeability and fractional collection efficiency analyzed for filtration of an airborne suspension of phosphatic rock in temperatures ranging from ambient to 700 degrees C. Results revealed that collection efficiency decreased with gas temperature and was enhanced with filtration time. Also, the support layer influenced the collection efficiency: the 75 ppi support was more effective than the 45 ppi. Particle collection efficiency dropped considerably for particles below 2 microm in diameter. The maximum collection occurred for particle diameters of approximately 3 microm, and decreased again for diameters between 4 and 8 microm. Such trend was successfully represented by the proposed correlation, which is based on the classical mechanisms acting on particle collection. Inertial impaction seems to be the predominant collection mechanism, with particle bouncing/re-entrainment acting as detachment mechanisms.

Up-regulation of peroxidase proliferator-activated receptor gamma in cholesteatoma.

PubMed

Hwang, Soon Jae; Kang, Hee Joon; Song, Jae-Jun; Kang, Jae Seong; Woo, Jeong Soo; Chae, Sung Won; Lee, Heung-Man

2006-01-01

To evaluate the localization and expression of peroxidase proliferator-activated receptor (PPAR)gamma in cholesteatoma epithelium. Experimental study. Reverse-transcription polymerase chain reaction was performed on cholesteatoma tissues from 10 adult patients undergoing tympanomastoid surgery for middle ear cholesteatoma and on 10 samples of normal external auditory canal skin tissue. The expression levels of PPARgamma to glyceraldehyde-3-phosphate dehydrogenase transcripts were semiquantified by densitometry. We also characterized the cellular localization of the PPARgamma protein immunohistochemically. Ki-67 was also localized to compare the proliferative activity of cells in cholesteatoma epithelium and in normal external auditory canal skin. PPARgamma mRNA and protein were detected in normal external auditory canal skin and in cholesteatoma epithelium. The expression level of PPARgamma mRNA in cholesteatoma was significantly increased compared with that in normal external auditory canal skin. PPARgamma protein was expressed in cells mainly in the granular and prickle cell layers. However, the intensity of its expression was generally decreased in the parabasal layer of the cholesteatoma epithelium. Ki-67 was expressed in the nuclei of cells in the basal and parabasal layers, and a greater number of cells were Ki-67 immunopositive in cholesteatoma epithelium. PPARgamma is up-regulated in the cholesteatoma epithelium compared with normal external auditory canal skin. These results suggest that PPARgamma may play an important role in the pathogenesis of cholesteatoma.

Layered Fault Rocks Below the West Salton Detachment Fault (WSDF), CA Record Multiple Seismogenic? Slip Events and Transfer of Material to a Fault Core

NASA Astrophysics Data System (ADS)

Axen, G. J.; Luther, A. L.; Selverstone, J.; Mozley, P.

2011-12-01

Unique layered cataclasites (LCs) occur locally along footwall splays, S of the ~N-dipping, top-E WSDF. They are well exposed in a NW-plunging antiform that folds the LCs and their upper and lower bounding faults. Layers range from very fine-grained granular shear zones 1-2 mm thick and cm's to m's long, to medium- to coarse-grained isotropic granular cataclasite with floating clasts up to 4-5 cm diameter in layers up to ~30 cm thick and 3 to >10 m long. The top, N-flank contact is ~5 m structurally below the main WSDF. Maximum thickness of the LCs is ~5 m on the S flank of the antiform, where the upper 10-50 cm of LCs are composed of relatively planar layers that are subparallel to the upper fault, which locally displays ultracataclasite. Deeper layers are folded into open to isoclinal folds and are faulted. Most shear-sense indicators show N-side-to-E or -SE slip, and include: (1) aligned biotite flakes and mm-scale shear bands that locally define a weak foliation dipping ~ESE, (2) sharp to granular shears, many of which merge up or down into fine-grained layers and, in the base of the overlying granodiorite, (3) primary reidel shears and (4) folded pegmatite dikes. Biotite is unaltered and feldspars are weakly to strongly altered to clays and zeolites. Zeolites also grew in pores between clasts. XRF analyses suggest minimal chemical alteration. The upper fault is sharp and relatively planar, carries granular to foliated cataclasitic granodiorite that grades up over ~2-4 m into punky, microcracked but plutonic-textured rock with much of the feldspar alteration seen in LC clasts. Some upper-plate reidels bend into parallelism with the top fault and bound newly formed LC layers. The basal fault truncates contorted layers and lacks evidence of layers being added there. We infer that the deeper, contorted layers are older and that the LC package grew upward by transfer of cataclasized slices from the overlying granodiorite while folding was ongoing. Particle-size distributions reflect constrained comminution and shear localization (slopes of ~3-3.5 on log-log plots of grain size vs. no. of grains > grain size). The LCs require episodic slip events that probably record dozens of seismic cycles. Foliation likely records post- or interseismic creep. Geometric complexities among the WSDF footwall splays presumably caused episodic dilation that allowed accumulation and folding of the LCs. Mechanical processes dominated over chemical processes. A key question is why the LCs apparently were stronger than the overlying granodiorite, leading to formation of new LC layers rather than significant reworking of older layers.

Statistical properties of gravity-driven granular discharge flow under the influence of an obstacle

NASA Astrophysics Data System (ADS)

Endo, Keita; Katsuragi, Hiroaki

2017-06-01

Two-dimensional granular discharge flow driven by gravity under the influence of an obstacle is experimentally investigated. A horizontal exit of width W is opened at the bottom of vertical Hele-Shaw cell filled with stainless-steel particles to start the discharge flow. In this experiment, a circular obstacle is placed in front of the exit. Thus, the distance between the exit and obstacle L is also an important parameter. During the discharge, granular-flow state is acquired by a high-speed camera. The bulk discharge-flow rate is also measured by load cell sensors. The obtained high-speed-image data are analyzed to clarify the particle-level granular-flow dynamics. Using the measured data, we find that the obstacle above the exit affects the granular- flow field. Specifically, the existence of obstacle results in large horizontal granular temperature and small packing fraction. This tendency becomes significant when L is smaller than approximately 6Dg when W ≃ 4Dg, where Dg is diameter of particles.

Resilient modulus characterization of Alaskan granular base materials.

DOT National Transportation Integrated Search

2010-08-01

When spring comes to cold regions, the active layer (the top few feet of soil that freezes and thaws seasonally) thaws quickly, while : deeper soil remains frozen. The active layer becomes saturated with water from snowmelt that collects atop the fro...

Redefining the effect of salt on thermophilic starter cell viability, culturability and metabolic activity in cheese.

PubMed

Hickey, C D; Fallico, V; Wilkinson, M G; Sheehan, J J

2018-02-01

This study investigated the differential effect of salt concentration in the outside and inside layers of brine salted cheeses on viability, culturability and enzyme activity of starter bacteria. The high-salt environment of the outside layer caused a sharp decrease in L. helveticus viability as measured by traditional plate counts. Remarkably, this was associated with lower release of intracellular enzymes (LDH), reduced levels of proteolysis and larger membrane integrity as measured by flow cytometry (FC) following classical Live/Dead staining. FC analysis of light scattering properties highlighted a significant reduction in size and granularity of the microbiota located in the cheese surface, suggestive of cell shrinkage and condensation of internal macromolecules probably due to hyperosmotic stress. The microbiota of the cheese surface were found to experience greater oxidative stress, as measured by FC analysis of the total levels of reactive oxygen species, compared to that of the interior layer. These results lead us to postulate that the physiology and health status of the microbiota were significantly different in the outer and inner layers of the cheese. The hyperosmotic environment of the outer layer resulted in reduced cell lysis, as measurable by assays based upon membrane integrity, but rather triggered cell death via mechanisms involving cell shrinkage and ROS-mediated damage of vital intracellular components. This study challenges the current thinking on how salt controls microbial activity in ripening cheese, especially in cheeses which are brine salted as local variations in biochemical ripening indices can differ significantly from the outside to the inside of a ripening cheese. Copyright © 2017 Elsevier Ltd. All rights reserved.

Comparison and Analysis of Membrane Fouling between Flocculent Sludge Membrane Bioreactor and Granular Sludge Membrane Bioreactor

PubMed Central

Zhi-Qiang, Chen; Jun-Wen, Li; Yi-Hong, Zhang; Xuan, Wang; Bin, Zhang

2012-01-01

The goal of this study is to investigate the effect of inoculating granules on reducing membrane fouling. In order to evaluate the differences in performance between flocculent sludge and aerobic granular sludge in membrane reactors (MBRs), two reactors were run in parallel and various parameters related to membrane fouling were measured. The results indicated that specific resistance to the fouling layer was five times greater than that of mixed liquor sludge in the granular MBR. The floc sludge more easily formed a compact layer on the membrane surface, and increased membrane resistance. Specifically, the floc sludge had a higher moisture content, extracellular polymeric substances concentration, and negative surface charge. In contrast, aerobic granules could improve structural integrity and strength, which contributed to the preferable permeate performance. Therefore, inoculating aerobic granules in a MBR presents an effective method of reducing the membrane fouling associated with floc sludge the perspective of from the morphological characteristics of microbial aggregates. PMID:22859954

Localization of organ-specific antigens in the nervous system of the rat.

PubMed

Weinrauder, H; Lach, B

1977-08-16

Localization of organ-specific brain antigens in the central nervous system of the rat has been studied by means of indirect immunofluorescence. Rabbit antiserum against homogenate of rat brain, previously absorbed with normal serum and homogenates of rat organs (kidney, liver, spleen), reacted with the water-soluble antigens of rat brain prepared by extraction with phosphate buffer (pH 7.3) and ultracentrifugation at 50 000 X g to give one band in the immunodiffusion test and 2--3 precipitation arcs in immunoelectrophoresis. There was also a positive reaction with peripheral nerve. The antigen was detectable in all regions of the CNS. Cells with distinct cytoplasmic immunofluorescence were most frequently observed in cerebellar white matter, pons, cerebellar pedunculi, longitudinal tracts of the brain stem. Positive immunofluorecence reaction has appeared in the outer plexiform layer and granular layer of the retina, satelite cells of the spinal root ganglia and Schwann cells. A similar reaction was observed in human, mouse and guinea pig brain slices. Both the morphological and immunochemical reactions are indicative of glial localization of this antigen.

Expression of Gas1 in Mouse Brain: Release and Role in Neuronal Differentiation.

PubMed

Bautista, Elizabeth; Zarco, Natanael; Aguirre-Pineda, Nicolás; Lara-Lozano, Manuel; Vergara, Paula; González-Barrios, Juan Antonio; Aguilar-Roblero, Raúl; Segovia, José

2018-05-01

Growth arrest-specific 1 (Gas1) is a pleiotropic protein that induces apoptosis of tumor cells and has important roles during development. Recently, the presence of two forms of Gas1 was reported: one attached to the cell membrane by a GPI anchor; and a soluble extracellular form shed by cells. Previously, we showed that Gas1 is expressed in different areas of the adult mouse CNS. Here, we report the levels of Gas1 mRNA protein in different regions and analyzed its expressions in glutamatergic, GABAergic, and dopaminergic neurons. We found that Gas1 is expressed in GABAergic and glutamatergic neurons in the Purkinje-molecular layer of the cerebellum, hippocampus, thalamus, and fastigial nucleus, as well as in dopaminergic neurons of the substantia nigra. In all cases, Gas1 was found in the cell bodies, but not in the neuropil. The Purkinje and the molecular layers show the highest levels of Gas1, whereas the granule cell layer has low levels. Moreover, we detected the expression and release of Gas1 from primary cultures of Purkinje cells and from hippocampal neurons as well as from neuronal cell lines, but not from cerebellar granular cells. In addition, using SH-SY5Y cells differentiated with retinoic acid as a neuronal model, we found that extracellular Gas1 promotes neurite outgrowth, increases the levels of tyrosine hydroxylase, and stimulates the inhibition of GSK3β. These findings demonstrate that Gas1 is expressed and released by neurons and promotes differentiation, suggesting an important role for Gas1 in cellular signaling in the CNS.

Abnormal proliferation of CD4- CD8+ gammadelta+ T cells with chromosome 6 anomaly: role of Fas ligand expression in spontaneous regression of the cells.

PubMed

Ichikawa, N; Kitano, K; Ito, T; Nakazawa, T; Shimodaira, S; Ishida, F; Kiyosawa, K

1999-04-01

We report a case of granular lymphocyte proliferative disorder accompanied with hemolytic anemia and neutropenia. Phenotypes of the cells were T cell receptor gammadelta+ CD3+ CD4- CD8+ CD16+ CD56- CD57-. Southern blot analysis of T cell receptor beta and gamma chains demonstrated rearranged bands in both. Chromosomal analysis after IL-2 stimulation showed deletion of chromosome 6. Sorted gammadelta+ T cells showed an increase in Fas ligand expression compared with the levels in sorted alphabeta+ T cells. The expression of Fas ligand on these gammadelta+ T cells increased after IL-2 stimulation. The patient's anemia improved along with a decrease in granular lymphocyte count and disappearance of the abnormal karyotype without treatment. The expression of Fas ligand may be involved in spontaneous regression of granular lymphocyte proliferation with hemolytic anemia.

Localization of the peroxisome proliferator-activated receptor in the brain.

PubMed

Kainu, T; Wikström, A C; Gustafsson, J A; Pelto-Huikko, M

1994-12-20

This paper describes the localization of the alpha-type peroxisome proliferator-activated receptor (PPAR alpha) in the rat brain using immunocytochemistry and in situ hybridization. Expression of PPAR alpha mRNA was highest in the granular cells of the cerebellar cortex and in the dentate gyrus, with a somewhat lower expression in areas CA1-CA4 of the hippocampus. PPAR alpha mRNA was also found in some neurones of the cerebral cortex (layers II-IV) and the molecular layer of the cerebellar cortex, and in the olfactory tubercle. Immunocytochemistry revealed nuclear PPAR alpha-immunoreactivity (-IR) in the same areas as seen with the in situ hybridization. Furthermore, PPAR alpha-IR was also localized in oligodendrocytes, whereas the other glial cell types appeared to lack PPAR alpha. These results suggest that peroxisome proliferators and chemicals acting similarly have effects on discrete populations of neurones. The presence of PPAR alpha in oligodendrocytes lends further support to the suggestion that peroxisomes are important in the assembly and degradation of myelin.

Large granular lymphocytosis in a patient infected with HTLV-II.

PubMed

Martin, M P; Biggar, R J; Hamlin-Green, G; Staal, S; Mann, D

1993-08-01

HTLV-II has been associated with a variety of lymphoproliferative disorders, including atypical hairy cell leukemia, chronic T cell leukemia, T prolymphocytic leukemia, and large granular lymphocytic leukemia. However, a direct or indirect role for HTLV-II in these disorders is not yet firmly established. We studied a patient diagnosed as having leukemia of the large granular lymphocyte (LGL) type who was HTLV-II seropositive, to determine if the expanded cell population was infected. Two populations of CD3-CD16+ LGL were identified; one was CD8+, the other CD8-. Populations of cells with these surface markers as well as normal CD3+CD4+ and CD3+CD8+ cells were separated by flow cytometric methods, DNA extracted, and gene regions of HTLV-II pol and tax amplified, using the polymerase chain reaction, and probed after Southern blotting. HTLV-II was detected in the CD3+CD8+ population, and not in the CD3-CD16+ large granular lymphocyte population. This finding indicates that the role of HTLV-II, if any, in LGL proliferation is indirect.

The nucleation of "fast" and "slow" stick slip instabilities in sheared granular aggregates

NASA Astrophysics Data System (ADS)

Korkolis, Evangelos; Ampuero, Jean-Paul; Niemeijer, André

2017-04-01

Seismological observations in the past few decades have revealed a diversity of slip behaviors of faults, involving interactions and transition between slow to fast slip phenomena. Field studies show that exhumed fault zones comprise mixtures of materials with variable frictional strength and stability. Emergent models of slip diversity emphasize the role of heterogeneities of fault zone properties and the potential interactions between seismic and aseismic deformation. Here, we develop analog laboratory experiments to study the mechanics of heterogeneous faults with the goal to identify factors controlling their slip stability and rupture style. We report on results from room temperature sliding experiments using a rotary shear apparatus. We simulated gouge heterogeneity by using materials with different frictional strength and stability. At room temperature conditions, dry glass beads typically stick slip, whereas dry granular calcite exhibits stable sliding. The peak strength of glass beads aggregates is typically lower than that of granular calcite aggregates. Our samples consisted of a layer of glass beads sandwiched between two layers of granular calcite. The initial particle size was between 100 and 200 μm for both materials and the initial thickness of each layer was about 1.5 mm. We tested our layered aggregates under 1 to 7 MPa normal stress and at sliding velocities between 1 and 100 μm/s. Within that range of conditions, high normal stress and slow sliding velocities promoted fast, regular stick slip. For normal stress values of less than about 4 MPa, the recurrence time and stress drop of stick slips became irregular, particularly at sliding rates above 20 μm/s. As the accumulated shear displacement increased, slip events became slower and the magnitudes of their stress drop, compaction and slip distance decreased. We recorded acoustic emissions (AEs) associated with each slip event (fast and slow) and estimated their source azimuth. AE activity was distributed in several clusters, some of which remained stationary, whereas others appeared to migrate with increasing shear displacement. We performed post-mortem microstructural analysis (tabletop SEM) of select AE nucleation sites and found significant mixing of glass beads with the calcite layer abutting the rotating piston ring. No mixing was observed between the glass beads and the calcite layer on the opposite side, nor any features that would indicate strain localization along the interface of the calcite and the adjacent stationary piston. These results show that the frictional behavior of our aggregates changed from fast to slow slip as the amount of glass beads mixed with granular calcite increased. Migrating AE clusters imply that nucleation occurred within the mixed calcite-glass beads layer, where most of the shear strain appears to have been accommodated, whereas stationary clusters probably originated within the adjacent, more slowly deforming layer of glass beads. This suggests that AEs belonging to migrating clusters were perhaps triggered by stress changes due to the gradual mixing of the two sample constituents. This process may explain migrating seismicity in natural fault zones.

Spatial and temporal localization during embryonic and fetal human development of the transcription factor SIM2 in brain regions altered in Down syndrome.

PubMed

Rachidi, Mohammed; Lopes, Carmela; Charron, Giselle; Delezoide, Anne-Lise; Paly, Evelyne; Bloch, Bernard; Delabar, Jean-Maurice

2005-08-01

Human SIM2 is the ortholog of Drosophila single-minded (sim), a master regulator of neurogenesis and transcriptional factor controlling midline cell fate determination. We previously localized SIM2 in a chromosome 21 critical region for Down syndrome (DS). Here, we studied SIM2 gene using a new approach to provide insights in understanding of its potential role in human development. For the first time, we showed SIM2 spatial and temporal expression pattern during human central nervous system (CNS) development, from embryonic to fetal stages. Additional investigations were performed using a new optic microscopy technology to compare signal intensity and cell density [M. Rachidi, C. Lopes, S. Gassanova, P.M. Sinet, M. Vekemans, T. Attie, A.L. Delezoide, J.M. Delabar, Regional and cellular specificity of the expression of TPRD, the tetratricopeptide Down syndrome gene, during human embryonic development, Mech. Dev. 93 (2000) 189--193]. In embryonic stages, SIM2 was identified predominantly in restricted regions of CNS, in ventral part of D1/D2 diencephalic neuroepithelium, along the neural tube and in a few cell subsets of dorsal root ganglia. In fetal stages, SIM2 showed differential expression in pyramidal and granular cell layers of hippocampal formation, in cortical cells and in cerebellar external granular and Purkinje cell layers. SIM2 expression in embryonic and fetal brain could suggest a potential role in human CNS development, in agreement with Drosophila and mouse Sim mutant phenotypes and with the conservation of the Sim function in CNS development from Drosophila to Human. SIM2 expression in human fetal brain regions, which correspond to key structures for cognitive processes, correlates well with the behavioral phenotypes of Drosophila Sim mutants and transgenic mice overexpressing Sim2. In addition, SIM2-expressing brain regions correspond to the altered structures in DS patients. All together, these findings suggest a potential role of SIM2 in CNS development and indicate that SIM2 overexpression could participate to the pathogenesis of mental retardation in Down syndrome patients.

Simulation of a Driven Dense Granular Gas

NASA Astrophysics Data System (ADS)

Bizon, Chris; Shattuck, M. D.; Swift, J. B.; Swinney, Harry L.

1998-11-01

Event driven particle simulations quantitatively reproduce the experimental results on vibrated granular layers, including the formation of standing wave patterns(C. Bizon, M.D. Shattuck, J.B. Swift, W.D. McCormick, and H.L. Swinney, Phys. Rev. Lett. 80), pp. 57-60 (1998). and secondary instabilities(J.R. deBruyn, C. Bizon, M.D. Shattuck, D. Goldman, J.B. Swift, and H.L. Swinney, Phys. Rev. Lett. 81) (1998), to appear. . In these simulations the velocity distributions are nearly Gaussian when scaled with the local fluctuational kinetic energy (granular temperature); this suggests that inelastic dense gas kinetic theory is applicable. We perform simulations of a two-dimensional granular gas that is homogeneously driven with fluctuating forces. We find that the equation of state differs from that of an elastic dense gas and that this difference is due to a change in the distribution of relative velocities at collisions. Granular thermal conductivity and viscosity are measured by allowing the fluctuating forces to have large scale spatial gradients.

Ultrastructure of the external gill epithelium of the axolotl, Ambystoma mexicanum with reference to ionic transport.

PubMed

Jarial, M S; Wilkins, J H

2003-10-01

The ultrastructure of the external gill epithelium of the axolotl, Ambystoma mexicanum, has been examined using conventional transmission electron microscopy to elucidate its role in ionic transport. Four cell types are identified in the gill filament and primary gill bar epithelium. These are granular, ciliated, Leydig and basal cells. A fifth cell type, the flat mitochondria-rich cell is only found in the gill bar epithelium. The predominant granular cells display microvilli at their surface and their cytoplasm contains abundant mitochondria, rough endoplasmic reticulum, Golgi complexes, vesicles and PAS+ secretory granules that are extruded at the surface, which along with secretions from the Leydig cells form a mucous coat. The granular cells are joined apically by junctional complexes consisting of zonulae occludens, zonulae adherens and desmosomes. The lateral membranes of granular cells enclose large intercellular spaces that are closed at the apical ends but remain open at the basal ends adjoining capillaries. In AgNO3-treated axolotl, the gills become darkly stained, the silver grains penetrate apical membranes and appear in the cytoplasm, accumulating near the lateral membranes and also enter the intercellular spaces. These findings are consistent with the dual role of the gill epithelium in mucus production and active ionic transport.

Optimizing pavement base, subbase, and subgrade layers for cost and performance of local roads : [tech transfer summary].

DOT National Transportation Integrated Search

2014-12-01

It is common for local street and road pavements to be constructed using : portland cement concrete (PCC) directly supported on natural subgrade : without considering subgrade treatment or structural support layers such : as granular subbase. In orde...

Gene expression and localization of two types of AQP5 in Xenopus tropicalis under hydration and dehydration.

PubMed

Shibata, Yuki; Sano, Takahiro; Tsuchiya, Nobuhito; Okada, Reiko; Mochida, Hiroshi; Tanaka, Shigeyasu; Suzuki, Masakazu

2014-07-01

Two types of aquaporin 5 (AQP5) genes (aqp-xt5a and aqp-xt5b) were identified in the genome of Xenopus tropicalis by synteny comparison and molecular phylogenetic analysis. When the frogs were in water, AQP-xt5a mRNA was expressed in the skin and urinary bladder. The expression of AQP-xt5a mRNA was significantly increased in dehydrated frogs. AQP-xt5b mRNA was also detected in the skin and increased in response to dehydration. Additionally, AQP-xt5b mRNA began to be slightly expressed in the lung and stomach after dehydration. For the pelvic skin of hydrated frogs, immunofluorescence staining localized AQP-xt5a and AQP-xt5b to the cytoplasm of secretory cells of the granular glands and the apical plasma membrane of secretory cells of the small granular glands, respectively. After dehydration, the locations of both AQPs in their respective glands did not change, but AQP-xt5a was visualized in the cytoplasm of secretory cells of the small granular glands. For the urinary bladder, AQP-xt5a was observed in the apical plasma membrane and cytoplasm of a number of granular cells under normal hydration. After dehydration, AQP-xt5a was found in the apical membrane and cytoplasm of most granular cells. Injection of vasotocin into hydrated frogs did not induce these changes in the localization of AQP-xt5a in the small granular glands and urinary bladder, however. The results suggest that AQP-xt5a might be involved in water reabsorption from the urinary bladder during dehydration, whereas AQP-xt5b might play a role in water secretion from the small granular gland. Copyright © 2014 the American Physiological Society.

ULTRASTRUCTURE OF THE NUCLEOLUS DURING THE CHINESE HAMSTER CELL CYCLE

PubMed Central

Noel, J. S.; Dewey, W. C.; Abel, J. H.; Thompson, R. P.

1971-01-01

Changes in the structure of the nucleolus during the cell cycle of the Chinese hamster cell in vitro were studied. Quantitative electron microscopic techniques were used to establish the size and volume changes in nucleolar structures. In mitosis, nucleolar remnants, "persistent nucleoli," consisting predominantly of ribosome-like granular material, and a granular coating on the chromosomes were observed. Persistent nucleoli were also observed in some daughter nuclei as they were leaving telophase and entering G1. During very early G1, a dense, fibrous material characteristic of interphase nucleoli was noted in the nucleoplasm of the cells. As the cells progressed through G1, a granular component appeared which was intimately associated with the fibrous material. By the middle of G1, complete, mature nucleoli were present. The nucleolar volume enlarged by a factor of two from the beginning of G1 to the middle of S primarily due to the accumulation of the granular component. During the G2 period, there was a dissolution or breakdown of the nucleolus prior to the entry of the cells into mitosis. Correlations between the quantitative aspects of this study and biochemical and cytochemical data available in the literature suggest the following: nucleolar reformation following division results from the activation of the nucleolar organizer regions which transcribe for RNA first appearing in association with protein as a fibrous component (45S RNA) and then later as a granular component (28S and 32S RNA). PMID:4933472

Is superficial burn caused by ultraviolet radiation (sunburn) comparable to superficial burn caused by heat--a histomorphological comparison by in vivo Reflectance-Mode-Confocal Microscopy.

PubMed

Altintas, M A; Altintas, A A; Guggenheim, M; Busch, K H; Niederbichler, A D; Aust, M C; Vogt, P M

2009-12-01

Regardless of the underlying cause, both sunburn and superficial thermal injuries are classified as first-degree burns, since data on morphological differences are scarce. Reflectance-Mode-Confocal Microscopy (RMCM) enables high-resolution non-invasive investigation of the human skin. We studied in vivo histomorphological alterations in both sunburn and superficial thermal injuries using RMCM. Ten patients (6 female, 4 male; aged 28.4 +/- 10.6 years) with first-degree thermal-contact Injuries (TI group), and 9 sunburned patients (SB group; 7 female, 2 male; aged 30.2 +/- 16.4 years), to a maximum extent of 10% of the body surface were evaluated 24 h after burn injury using RMCM. The following parameters were obtained using RMCM: stratum corneum thickness, epidermal thickness, basal layer thickness, granular cell size. Compared to the controls (12.8 +/- 2.5 microm), stratum corneum thickness decreased significantly to 10.6 +/- 2.1 microm in the TI group, whereas it increased significantly to 16.4 +/- 3.1 microm in the SB group. The epidermal thickness did not differ significantly in the TI group (47.9 +/- 2.3 microm) and SB group (49.1 +/- 3.5 microm); however, both increased significantly compared to their respective controls (41.8 +/- 1.4 microm). The basal layer thickness increased more in the SB group compared to the TI group (17.9 +/- 1.4 microm vs. 15.6 +/- 1.1 microm). Both differed also significantly compared to their controls (13.8 +/- 0.9 microm). The granular cell size increased significantly in both groups compared to the controls (731 +/- 42 microm); however, a significantly higher increase was observed in the TI group (852 +/- 58 microm) compared to the SB group (784 +/- 61 microm). Ultraviolet radiation seems to influence predominantly deeper epidermal layers, whereas heat-induced burns affect more superficial epidermal layers. The term 'First-degree burn' should not be used synonymously for sunburn and superficial thermal burn injuries. Conflicts of interest None declared.

Voxelized Computational Model for Convection-Enhanced Delivery in the Rat Ventral Hippocampus: Comparison with In Vivo MR Experimental Studies

PubMed Central

Kim, Jung Hwan; Astary, Garrett W.; Kantorovich, Svetlana; Mareci, Thomas H.; Carney, Paul R.; Sarntinoranont, Malisa

2012-01-01

Convection-enhanced delivery (CED) is a promising local delivery technique for overcoming the blood–brain barrier (BBB) and treating diseases of the central nervous system (CNS). For CED, therapeutics are infused directly into brain tissue and the drug agent is spread through the extracellular space, considered to be highly tortuous porous media. In this study, 3D computational models developed using magnetic resonance (MR) diffusion tensor imaging data sets were used to predict CED transport in the rat ventral hippocampus using a voxelized modeling previously developed by our group. Predicted albumin tracer distributions were compared with MR-measured distributions from in vivo CED in the ventral hippocampus up to 10 μL of Gd-DTPA albumin tracer infusion. Predicted and measured tissue distribution volumes and distribution patterns after 5 and 10 μL infusions were found to be comparable. Tracers were found to occupy the underlying landmark structures with preferential transport found in regions with less fluid resistance such as the molecular layer of the dentate gyrus. Also, tracer spread was bounded by high fluid resistance layers such as the granular cell layer and pyramidal cell layer of dentate gyrus. Leakage of tracers into adjacent CSF spaces was observed towards the end of infusions. PMID:22532321

Laminar and cytoarchitectonic features of the cerebral cortex in the Risso's dolphin (Grampus griseus), striped dolphin (Stenella coeruleoalba), and bottlenose dolphin (Tursiops truncatus).

PubMed

Furutani, Rui

2008-09-01

The present investigation carried out Nissl, Klüver-Barrera, and Golgi studies of the cerebral cortex in three distinct genera of oceanic dolphins (Risso's dolphin, striped dolphin and bottlenose dolphin) to identify and classify cortical laminar and cytoarchitectonic structures in four distinct functional areas, including primary motor (M1), primary sensory (S1), primary visual (V1), and primary auditory (A1) cortices. The laminar and cytoarchitectonic organization of each of these cortical areas was similar among the three dolphin species. M1 was visualized as five-layer structure that included the molecular layer (layer I), external granular layer (layer II), external pyramidal layer (layer III), internal pyramidal layer (layer V), and fusiform layer (layer VI). The internal granular layer was absent. The cetacean sensory-related cortical areas S1, V1, and A1 were also found to have a five-layer organization comprising layers I, II, III, V and VI. In particular, A1 was characterized by the broadest layer I, layer II and developed band of pyramidal neurons in layers III (sublayers IIIa, IIIb and IIIc) and V. The patch organization consisting of the layer IIIb-pyramidal neurons was detected in the S1 and V1, but not in A1. The laminar patterns of V1 and S1 were similar, but the cytoarchitectonic structures of the two areas were different. V1 was characterized by a broader layer II than that of S1, and also contained the specialized pyramidal and multipolar stellate neurons in layers III and V.

Regenerable device for scrubbing breathable air of CO2 and moisture without special heat exchanger equipment

NASA Technical Reports Server (NTRS)

Tepper, E. H. (Inventor)

1977-01-01

The device concerns the circulation of cabin air through canisters which absorb and adsorb carbon dioxide, together with excess moisture, and return the scrubbed air to the cabin for recirculation. A coating on an inert substrate in granular form absorbs and adsorbs the impurities at standard temperatures and pressures, but desorbs such impurities at low pressures (vacuum) and standard temperatures. This fact is exploited by making the device in a stack of cells consisting of layers or cells which are isolated from one another flow-wise and are connected to separate manifolds and valving systems into two separate subsets. A first subset may be connected for the flow breathable air therethrough until the polyethyleneimine of its cells is saturated with CO2 and H2O. During the same period the second subset of cells is manifolded to a vacuum source.

Granular Formation during Apoptosis in Blastocystis sp. Exposed to Metronidazole (MTZ)

PubMed Central

Suresh, Kumar; Tan, Tian Chye

2016-01-01

The role and function of the granular life cycle stage in Blastocystis sp, remains uncertain despite suggestions being made that the granules are metabolic, reproductive and lipid in nature. This present study aims to understand granular formation by triggering apoptosis in Blastocystis sp. by treating them with metronidazole (MTZ). Blastocystis sp.cultures of 4 sub-types namely 1, 2, 3 and 5 when treated with 0.01 and 0.0001 mg/ml of metronidazole (MTZ) respectively showed many of the parasites to be both viable and apoptotic (VA). Treated subtype 3 isolates exhibited the highest number of granular forms i.e. 88% (p<0.001) (0.0001 mg/ml) and 69% (p<0.01) (0.01 mg/ml) respectively at the 72 h in in vitro culture compared to other subtypes. These VA forms showed distinct granules using acridine orange (AO) and 4’,6-diamino-2-phenylindole (DAPI) staining with a mean per cell ranging from 5 in ST 5 to as high as 16 in ST 3. These forms showed intact mitochondria in both viable apoptotic (VA) and viable non-apoptotic (VNA) cells with a pattern of accumulation of lipid droplets corresponding to viable cells. Granular VA forms looked ultra-structurally different with prominent presence of mitochondria-like organelle (MLO) and a changed mitochondrial trans-membrane potential with thicker membrane and a highly convoluted inner membrane than the less dense non-viable apoptotic (NVA) cells. This suggests that granular formation during apoptosis is a self-regulatory mechanism to produce higher number of viable cells in response to treatment. This study directs the need to search novel chemotherapeutic approaches by incorporating these findings when developing drugs against the emerging Blastocystis sp. infections. PMID:27471855

Fluorescence histochemical and elec-ron microscopical observations on sympathetic ganglia of the chick embryo cultured with and without hydrocortisone.

PubMed

Hervonen, H; Eränkö, O

1975-01-01

Lumbar sympathetic ganglia of 12-day-old chick embryos were cultured in organ cultures for 14 days with 1, 10 or 100 mg/l of hydrocortisone or without it. Catecholamines were demonstrated by the formaldehyde-induced fluorescence method. For electron microscopy, the cultures were fixed with glutarialdehyde and osmium tetroxide. Two types of cells with catecholamine fluoresecence were observed in the control cultures: (1) weakly fluorescent sympathetic neurons and sympathicoblasts with long nerve fibres, which were the most common cell type in the explant, and (2) brightly fluorescent cells with or without fluorescent processes, which were less common and were scattered in the explant. Hydrocortisone caused a great increase in the number of the brightly fluorescent cells. With 10 mg/l of hydrocortisone the increase was about ten-fold as compared with the control cultures. There was no change in the morphology of the cells, nor could any change be observed in the fluorescence intensity by eye. Electron microscopically the mature neurons were the most common cell type on the surface of the culture, while more immature sympathicoblasts were seen in the deeper layers. Cells were also found which contained large numbers of catecholamine-strong granular vesicles 105-275 nm in diameter. These cells were infrequent. They had round vesicular nuclei and resembled also in other respects sympathicoblasts or young nerve cells. One such cell was found in mitotic division by electron microscopy. Hydrocortisone caused a marked increase in the number of these granule-containing cells and their processes. Cells which could have been classified as the small intensely fluorescent cells of the mammalian ganglion type or their electron microscopic equivalent, the granule-containing cells were found neither in the control cultures nor in the hydrocortisone-containing cultures. It is concluded that most brightly fluorescent cells in cultured sympathetic ganglia of the chick are nerve cells or sympathicoblasts rich in amine-storing granular vesicles.

Morphology-based optical separation of subpopulations from a heterogeneous murine breast cancer cell line.

PubMed

Tamura, Masato; Sugiura, Shinji; Takagi, Toshiyuki; Satoh, Taku; Sumaru, Kimio; Kanamori, Toshiyuki; Okada, Tomoko; Matsui, Hirofumi

2017-01-01

Understanding tumor heterogeneity is an urgent and unmet need in cancer research. In this study, we used a morphology-based optical cell separation process to classify a heterogeneous cancer cell population into characteristic subpopulations. To classify the cell subpopulations, we assessed their morphology in hydrogel, a three-dimensional culture environment that induces morphological changes according to the characteristics of the cells (i.e., growth, migration, and invasion). We encapsulated the murine breast cancer cell line 4T1E, as a heterogeneous population that includes highly metastatic cells, in click-crosslinkable and photodegradable gelatin hydrogels, which we developed previously. We observed morphological changes within 3 days of encapsulating the cells in the hydrogel. We separated the 4T1E cell population into colony- and granular-type cells by optical separation, in which local UV-induced degradation of the photodegradable hydrogel around the target cells enabled us to collect those cells. The obtained colony- and granular-type cells were evaluated in vitro by using a spheroid assay and in vivo by means of a tumor growth and metastasis assay. The spheroid assay showed that the colony-type cells formed compact spheroids in 2 days, whereas the granular-type cells did not form spheroids. The tumor growth assay in mice revealed that the granular-type cells exhibited lower tumor growth and a different metastasis behavior compared with the colony-type cells. These results suggest that morphology-based optical cell separation is a useful technique to classify a heterogeneous cancer cell population according to its cellular characteristics.

Membrane biofouling mechanism in an aerobic granular reactor degrading 4-chlorophenol.

PubMed

Buitrón, Germán; Moreno-Andrade, Iván; Arellano-Badillo, Víctor M; Ramírez-Amaya, Víctor

2014-01-01

The membrane fouling of an aerobic granular reactor coupled with a submerged membrane in a sequencing batch reactor (SBR) was evaluated. The fouling analysis was performed by applying microscopy techniques to determine the morphology and structure of the fouling layer on a polyvinylidene fluoride membrane. It was found that the main cause of fouling was the polysaccharide adsorption on the membrane surface, followed by the growth of microorganisms to form a biofilm.

Discontinuous Inter-Granular Separations (DIGS) in the Gas Nitride Layer of ISS Race Rings

NASA Technical Reports Server (NTRS)

Figert, John; Dasgupta, Rajib; Martinez, James

2010-01-01

The starboard solar alpha rotary joint (SARJ) race ring on the International space station (ISS) failed due to severe spalling of the outer diameter, 45 degree (outer canted) nitrided surface. Subsequent analysis at NASA-KSC revealed that almost all of the debris generated due to the failure was nitrided 15-5 stainless steel. Subsequent analysis of the nitride control coupons (NCC) at NASA-JSC revealed the presence of discontinuous inter-granular separations (DIGS) in the gas nitride layer. These DIGS were present in the inter-granular networking located in the top 2 mils of the nitride layer. The manufacturer's specification requires the maximum white structure to be 0.0003 inches and intergranular networking below the allowable white structure depth to be cause for rejection; a requirement that the NCCs did not meet. Subsequent testing and analysis revealed that lower DIGS content significantly lowered the probability of nitride spalling in simulated, dry condition runs. One batch of nitride samples with DIGS content similar to the port SARJ (did not fail on orbit) which exhibited almost no nitride spalling after being run on one test rig. Another batch of nitride samples with DIGS content levels similar to the starboard SARJ exhibited significant nitride spalling on the same test rig with the same load under dry conditions. Although DIGS were not the root cause of starboard race ring failure, testing indicates that increased DIGS reduced the robustness of the gas nitride layer under dry operating conditions.

Rheology of surface granular flows

NASA Astrophysics Data System (ADS)

Orpe, Ashish V.; Khakhar, D. V.

Surface granular flow, comprising granular material flowing on the surface of a heap of the same material, occurs in several industrial and natural systems. The rheology of such a flow was investigated by means of measurements of velocity and number-density profiles in a quasi-two-dimensional rotating cylinder, half-filled with a model granular material monosize spherical stainless-steel particles. The measurements were made at the centre of the cylinder, where the flow is fully developed, using streakline photography and image analysis. The stress profile was computed from the number-density profile using a force balance which takes into account wall friction. Mean-velocity and root-mean-square (r.m.s.)-velocity profiles are reported for different particle sizes and cylinder rotation speeds. The profiles for the mean velocity superimpose when distance is scaled by the particle diameter d and velocity by a characteristic shear rate dot{gamma}_C = [gsin(beta_m-beta_s)/dcosbeta_s](1/2) and the particle diameter, where beta_m is the maximum dynamic angle of repose and beta_s is the static angle of repose. The maximum dynamic angle of repose is found to vary with the local flow rate. The scaling is also found to work for the r.m.s. velocity profiles. The mean velocity is found to decay exponentially with depth in the bed, with decay length lambda=1.1d. The r.m.s. velocity shows similar behaviour but with lambda=1.7d. The r.m.s. velocity profile shows two regimes: near the free surface the r.m.s. velocity is nearly constant and below a transition point it decays linearly with depth. The shear rate, obtained by numerical differentiation of the velocity profile, is not constant anywhere in the layer and has a maximum which occurs at the same depth as the transition in the r.m.s. velocity profile. Above the transition point the velocity distributions are Gaussian and below the transition point the velocity distributions gradually approach a Poisson distribution. The shear stress increases roughly linearly with depth. The variation in the apparent viscosity eta with r.m.s. velocity u shows a relatively sharp transition at the shear-rate maximum, and in the region below this point the apparent viscosity eta˜ u(-1.5) . The measurements indicate that the flow comprises two layers: an upper low-viscosity layer with a nearly constant r.m.s. velocity and a lower layer of increasing viscosity with a decreasing r.m.s. velocity. The thickness of the upper layer depends on the local flow rate and is independent of particle diameter while the reverse is found to hold for the lower-layer thickness. The experimental data is compared with the predictions of three models for granular flow.

Central granular cell odontogenic tumor: Report of an unusual case.

PubMed

Madan, Mani; Chandra, Shaleen; Raj, Vineet; Madan, Rohit

2016-01-01

Central granular cell odontogenic tumor (CGCOT) is an unusual benign odontogenic neoplasm characterized by the presence of granular cells associated with apparently inactive odontogenic epithelium. These tumors tend to occur in the posterior mandible and usually present as well-defined unilocular or multilocular radiolucent lesions. So far, only <40 cases of CGCOT have been described in the literature under various terminologies. Though these tumors were not considered as distinct entity in the recent WHO classification of odontogenic tumors, long-term follow-up is recommended as malignant counterpart of CGCOT has already been reported. The main aim of this article is to report an additional case of CGCOT to the literature, occurring in a 73-year-old male.

SUBFIELD AND LAYER-SPECIFIC DEPLETION IN CALBINDIN-D28K, CALRETININ AND PARVALBUMIN IMMUNOREACTIVITY IN THE DENTATE GYRUS OF APP/PS1 TRANSGENIC MICE

PubMed Central

Popovi, Miroljub; Caballero-Bleda, María; Kadish, Inga; van Groen, Thomas

2008-01-01

The depletion of neuronal calcium binding proteins deprives neurons of the capacity to buffer high levels of intracellular Ca2+ and this leaves them vulnerable to pathological processes, such as those present in Alzheimer’s disease (AD). The aim of the present study was to investigate the expression of the calcium binding proteins, calbindin-D28K, calretinin and parvalbumin in the dentate gyrus (DG) of APP/PS1 transgenic mice and their non-Tg littermates, as well as the relation with the deposition of human Aβ. We measured the expression of these three proteins at seven different rostro-caudal levels, and in the molecular, granular and polymorphic layers of the DG. We found that, except in the most caudal part of the DG, there is a substantial loss of calbindin-D28K immunoreactivity in all three layers of the DG in APP/PS1 mice compared to the non-Tg mice. Significant loss of calretinin immunoreactivity is present in most of the polymorphic layer of the DG of APP/PS1 mice compared to the non-Tg mice, as well as in the rostral and intermediate part of the inner molecular layer. Compared to the non-Tg mice parvalbumin immunoreactivity is significantly reduced throughout the whole polymorphic layer as well as in the rostral and intermediate part of the granular layer of DG in APP/PS1 mice. The relatively preservation of calbindin immunoreactivity in the caudal part of molecular and granular layers as well as calretinin immunoreactivity in the caudal part of polymorphic layer of the DG is likely related to the lower Aβ expression in those parts of DG. The present data suggest an involvement of calcium-dependent pathways in the pathogenesis of AD and indicate that there exists a subfield and layer-specific decrease in immunoreactivity which is related to the type of calcium-binding protein in APP/PS1 mice. Moreover, it seems that APP expression affects more the calbindin expression then parvalbumin and calretinin expression in the DG of APP/PS1 transgenic mice. PMID:18583063

Granular Material Scoop and Near-Vertical Lifting Feeder/Conveyor

NASA Technical Reports Server (NTRS)

Walton, Otis (Inventor); Vollmer, Hubert J. (Inventor)

2017-01-01

An integrated granular-material scoop and near-vertical lifting feeder/conveyor includes special connections and skirts between a bullnose rotating scoop and an open-helical screw that provides the rotations and material lift and evacuation. A conical working-face of the bullnose rotating scoop has symmetrically distributed graters and vents to break loose and force-in granular material from natural deposits and cargo holds. The bullnose rotating scoop and the open-helical screw its attached to move the material into a continuous layer on the inside surface of an outer stationary sheathing. A motor drive attached to the open-helical screw above at the delivery end provides the lifting force necessary.

Central granular cell odontogenic tumor: a systematic review.

PubMed

Sarode, Sachin C; Sarode, Gargi S; Vaidya, Kedar

2014-03-01

Central granular cell odontogenic tumor (CGCOT) is a rare benign odontogenic neoplasm reported with various terms and is not included in the 2005 WHO classification of odontogenic tumors. It shows a predilection for middle-aged women, usually presenting as an asymptomatic swelling of the mandibular premolar-molar region. Radiographic manifestations include unilocular or multilocular radiolucent lesion, but mixed density lesions can also occur. Histopathology shows sheets and lobules of round to polygonal cells with abundant eosinophilic, granular cytoplasm and eccentrically placed nuclei. Immunohistochemical and ultrastructural features suggest the histiocytic origin of granular cells. The neoplasm does not exhibit an aggressive biological behavior and hence enucleation or curettage ensuring complete removal remains the treatment of choice. We present a systematic review on clinical, radiological, histopathological, immunohistochemical and treatment aspect of CGCOT. Published articles were identified through a literature search using online databases (PubMed, MEDLINE, Scopus) and cross-references for papers published from the year 1950 to March 2013. From a total of 37 papers, 26 (38 cases) were extracted from the database for systematic review. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Endoscopic submucosal dissection for esophageal granular cell tumor using the clutch cutter

PubMed Central

Komori, Keishi; Akahoshi, Kazuya; Tanaka, Yoshimasa; Motomura, Yasuaki; Kubokawa, Masaru; Itaba, Soichi; Hisano, Terumasa; Osoegawa, Takashi; Nakama, Naotaka; Iwao, Risa; Oya, Masafumi; Nakamura, Kazuhiko

2012-01-01

Endoscopic submucosal dissection (ESD) with a knife is a technically demanding procedure associated with a high complication rate. The shortcomings of this method are the deficiencies of fixing the knife to the target lesion, and of compressing it. These shortcomings can lead to major complications such as perforation and bleeding. To reduce the risk of complications related to ESD, we developed a new grasping type scissors forceps (Clutch Cutter®, Fujifilm, Japan) which can grasp and incise the targeted tissue using an electrosurgical current. Esophagogastroduodenoscopy on a 59-year-old Japanese man revealed a 16mm esophageal submucosal nodule with central depression. Endoscopic ultrasonography demonstrated a hypoechoic solid tumor limited to the submucosa without lymph node involvement. The histologic diagnosis of the specimen obtained by biopsy was granular cell tumor. It was safely and accurately resected without unexpected incision by ESD using the CC. No delayed hemorrhage or perforation occurred. Histological examination confirmed that the granular cell tumor was completely excised with negative resection margin.We report herein a case of esophageal granular cell tumor successfully treated by an ESD technique using the CC. PMID:22267979

Effect of periodic fluctuation of soil particle rotation resistance on interface shear behaviour

NASA Astrophysics Data System (ADS)

Ebrahimian, Babak; Noorzad, Asadollah

2010-06-01

The interface behaviour between infinite extended narrow granular layer and bounding structure is numerically investigated using finite element method. The micro-polar (Cosserat) continuum approach within the framework of elasto-plasticity is employed to remove the numerical difficulties caused by strain-softening of materials in classical continuum mechanics. Mechanical properties of cohesionless granular soil are described with Lade's model enhanced with polar terms including Cosserat rotations, curvatures and couple stresses via mean grain diameter as the internal length. The main attention of paper is laid on the influence of spatial periodic fluctuation of rotation resistance of soil particles interlocked with the surface of bounding structure on evolution and location of shear band developed inside granular body. The finite element results demonstrate that the location and evolution of shear localization in granular body is strongly affected by prescribed non-uniform micro-polar kinematic boundary conditions along the interface.

An experimental study of the transient regime to fluidized chimney in a granular medium

NASA Astrophysics Data System (ADS)

Philippe, Pierre; Mena, Sarah; Brunier-Coulin, Florian; Curtis, Jennifer

2017-06-01

Localized fluidization within a granular packing along an almost cylindrical chimney is observed when an upward fluid-flow, injected through a small port diameter, exceeds a critical flow-rate. Once this threshold reached, a fluidized area is first initiated in the close vicinity of the injection hole before gradually growing upward to the top surface of the granular layer. In this work, we present an experimental investigation specifically dedicated to the kinetics of chimney fluidization in an immersed granular bed. Two different transient regimes are identified depending on wether the expansion of the fluidized area is rather fast and regular, reaching the final chimney state typically in less than 10 seconds, or, on the contrary, slow and very progressively accelerated, giving rise to transient duration up to 1 hour or even more. Some systematic investigations allow to propose several empirical scaling relations for the kinetics of chimney fluidization in the fast regular regime.

Granular Security in a Graph Database

DTIC Science & Technology

2016-03-01

have a presence in more than one layer. For example, a single social media user may have an account in Twitter, Facebook, and Instagram with... Instagram layers. This restriction re- flects the reality that user A’s Facebook account cannot connect directly to user B’s Twitter account. A security

Up-Regulation of Long Noncoding RNA SRA Promotes Cell Growth, Inhibits Cell Apoptosis, and Induces Secretion of Estradiol and Progesterone in Ovarian Granular Cells of Mice.

PubMed

Li, Yan; Wang, Haixu; Zhou, Dangxia; Shuang, Ting; Zhao, Haibo; Chen, Biliang

2018-04-20

BACKGROUND Increasing evidence indicates that long noncoding RNAs (LncRNAs) play a key role in multiple pathological processes. It has been shown that LncRNA steroid receptor RNA activator (SRA) is elevated in peripheral blood of patients with polycystic ovary syndrome (PCOS). The aim of this study was to assess the effect of elevated LncRNA SRA on ovarian granular cells of mice in vitro. MATERIAL AND METHODS We firstly isolated granular cells from mouse ovaries and over-expressed the LncRNA SRA by means of lentiviral transfection in this cell line. Then, we assessed the effects of LncRNA SRA on granular cells through real-time PCR, CCK-8 assay, flow cytometry, Hoechst staining, and Western blot assay. RESULTS We demonstrated that elevated LncRNA SRA stimulated cell growth, changed distribution of cell cycle phases with increase of Cyclin B, Cyclin E, and Cyclin D1, and inhibited cell apoptosis with up-regulation of bcl2 and down-regulation of bax, cleaved-caspase 3, and cleaved-PARP. Moreover, the contents of estradiol (E2) and progesterone (PG) and expressions of their key enzymes (CYP19A1 and CYP11A1) were up-regulated following over-expression of LncRNA SRA. CONCLUSIONS Taken together, our results indicate that abnormal LncRNA SRA may be a risk factor for evoking PCOS.

Morphological and populational characteristics of hemocytes of Ornithodoros moubata nymphs during the ecdysial phase.

PubMed

Kadota, K; Walter, S; Claveria, F G; Igarashi, I; Taylor, D; Fujisaki, K

2003-11-01

The ultrastructure and characteristics of hemocytes of argasid tick species, Ornithodoros moubata, during the ecdysdial phase are herein presented. Hemocyte classes/populations characterized based on their affinity with Giemsa stain and ultrastructural differences comprised the prohemocytes, nongranular cells (Nc), eosinophilic granular cells (Ec), basophilic granular cells (Bc), and unidentified cells. Significant changes/shift in the ratio of hemocyte classes/population was apparent in ticks before and after the ecdysial phase. The granule-scant basophilic granular cells (sBc) constituted the most abundant hemocyte population in the ecdysial phase. Nymphs in ecdysis showed increases in Nc and sBc and decrease in Ec, a phenomenon that was reversed in unengorged nymphs and adults ticks. The significant increase in total Bc population in ecdysis relative to nonengorged ticks clearly point to blastogenesis of Bc taking place during the ecdysial phase and Bc's important role in the process of tissue remodeling.

Kolaviron and vitamin E ameliorate hematotoxicity and oxidative stress in brains of prepubertal rats treated with an anticonvulsant phenytoin.

PubMed

Owoeye, Olatunde; Adedara, Isaac A; Bakare, Oluwafemi S; Adeyemo, Oluwatobi A; Egun, Christa; Farombi, Ebenezer O

2014-06-01

Phenytoin (PHT), an anticonvulsant agent, widely used for the treatment of epilepsy has been reported to exhibit toxic side effects. The present study investigated the protective effects of kolaviron and vitamin E on hematotoxicity and neurotoxicity induced by phenytoin, in prepubertal male rats. The animals were treated with PHT (75 mg/kg) separately or in combination with either kolaviron (200 mg/kg) or vitamin E (500 mg/kg) for 14 days. Phenytoin treatment significantly decreased the hemoglobin, white blood cells, lymphocytes and mean corpuscular volume levels without affecting red blood cell, packed cell volume, neutrophils, mean corpuscular hemoglobin and mean corpuscular hemoglobin concentration when compared with the control rats. There was a significant increase in lipid peroxidation and hydrogen peroxide levels with marked depletion in antioxidant status in brains of PHT-treated rats when compared with the control. Although PHT treatment had no effect on the granular layer, widest diameter of Purkinje cells and Purkinje layer of the cerebellum, it significantly reduced its molecular layer and the density of Purkinje cell. Administration of PHT significantly reduced the densities of the granule cells of the dentate gyrus and the pyramidal neurons of the cornu ammonis of hippocampus proper. Co-treatment with kolaviron and vitamin E effectively reversed the PHT-mediated alterations in the hematology, brain antioxidant status and histomorphometry when compared to PHT only. Taken together, the present data indicate the abilities of kolaviron and vitamin E to ameliorate phenytoin-induced hematotoxicity and oxidative stress in brains of rats.

Example study for granular bioreactor stratification: Three-dimensional evaluation of a sulfate-reducing granular bioreactor

PubMed Central

Hao, Tian-wei; Luo, Jing-hai; Su, Kui-zu; Wei, Li; Mackey, Hamish R.; Chi, Kun; Chen, Guang-Hao

2016-01-01

Recently, sulfate-reducing granular sludge has been developed for application in sulfate-laden water and wastewater treatment. However, little is known about biomass stratification and its effects on the bioprocesses inside the granular bioreactor. A comprehensive investigation followed by a verification trial was therefore conducted in the present work. The investigation focused on the performance of each sludge layer, the internal hydrodynamics and microbial community structures along the height of the reactor. The reactor substratum (the section below baffle 1) was identified as the main acidification zone based on microbial analysis and reactor performance. Two baffle installations increased mixing intensity but at the same time introduced dead zones. Computational fluid dynamics simulation was employed to visualize the internal hydrodynamics. The 16S rRNA gene of the organisms further revealed that more diverse communities of sulfate-reducing bacteria (SRB) and acidogens were detected in the reactor substratum than in the superstratum (the section above baffle 1). The findings of this study shed light on biomass stratification in an SRB granular bioreactor to aid in the design and optimization of such reactors. PMID:27539264

Aqueous synthesis of LiFePO4 with Fractal Granularity.

PubMed

Cabán-Huertas, Zahilia; Ayyad, Omar; Dubal, Deepak P; Gómez-Romero, Pedro

2016-06-03

Lithium iron phosphate (LiFePO4) electrodes with fractal granularity are reported. They were made from a starting material prepared in water by a low cost, easy and environmentally friendly hydrothermal method, thus avoiding the use of organic solvents. Our method leads to pure olivine phase, free of the impurities commonly found after other water-based syntheses. The fractal structures consisted of nanoparticles grown into larger micro-sized formations which in turn agglomerate leading to high tap density electrodes, which is beneficial for energy density. These intricate structures could be easily and effectively coated with a thin and uniform carbon layer for increased conductivity, as it is well established for simpler microstructures. Materials and electrodes were studied by means of XRD, SEM, TEM, SAED, XPS, Raman and TGA. Last but not least, lithium transport through fractal LiFePO4 electrodes was investigated based upon fractal theory. These water-made fractal electrodes lead to high-performance lithium cells (even at high rates) tested by CV and galvanostatic charge-discharge, their performance is comparable to state of the art (but less environmentally friendly) electrodes.

Aqueous synthesis of LiFePO4 with Fractal Granularity

PubMed Central

Cabán-Huertas, Zahilia; Ayyad, Omar; Dubal, Deepak P.; Gómez-Romero, Pedro

2016-01-01

Lithium iron phosphate (LiFePO4) electrodes with fractal granularity are reported. They were made from a starting material prepared in water by a low cost, easy and environmentally friendly hydrothermal method, thus avoiding the use of organic solvents. Our method leads to pure olivine phase, free of the impurities commonly found after other water-based syntheses. The fractal structures consisted of nanoparticles grown into larger micro-sized formations which in turn agglomerate leading to high tap density electrodes, which is beneficial for energy density. These intricate structures could be easily and effectively coated with a thin and uniform carbon layer for increased conductivity, as it is well established for simpler microstructures. Materials and electrodes were studied by means of XRD, SEM, TEM, SAED, XPS, Raman and TGA. Last but not least, lithium transport through fractal LiFePO4 electrodes was investigated based upon fractal theory. These water-made fractal electrodes lead to high-performance lithium cells (even at high rates) tested by CV and galvanostatic charge-discharge, their performance is comparable to state of the art (but less environmentally friendly) electrodes. PMID:27256504

Aqueous synthesis of LiFePO4 with Fractal Granularity

NASA Astrophysics Data System (ADS)

Cabán-Huertas, Zahilia; Ayyad, Omar; Dubal, Deepak P.; Gómez-Romero, Pedro

2016-06-01

Lithium iron phosphate (LiFePO4) electrodes with fractal granularity are reported. They were made from a starting material prepared in water by a low cost, easy and environmentally friendly hydrothermal method, thus avoiding the use of organic solvents. Our method leads to pure olivine phase, free of the impurities commonly found after other water-based syntheses. The fractal structures consisted of nanoparticles grown into larger micro-sized formations which in turn agglomerate leading to high tap density electrodes, which is beneficial for energy density. These intricate structures could be easily and effectively coated with a thin and uniform carbon layer for increased conductivity, as it is well established for simpler microstructures. Materials and electrodes were studied by means of XRD, SEM, TEM, SAED, XPS, Raman and TGA. Last but not least, lithium transport through fractal LiFePO4 electrodes was investigated based upon fractal theory. These water-made fractal electrodes lead to high-performance lithium cells (even at high rates) tested by CV and galvanostatic charge-discharge, their performance is comparable to state of the art (but less environmentally friendly) electrodes.

Laminar and cytoarchitectonic features of the cerebral cortex in the Risso's dolphin (Grampus griseus), striped dolphin (Stenella coeruleoalba), and bottlenose dolphin (Tursiops truncatus)

PubMed Central

Furutani, Rui

2008-01-01

The present investigation carried out Nissl, Klüver-Barrera, and Golgi studies of the cerebral cortex in three distinct genera of oceanic dolphins (Risso's dolphin, striped dolphin and bottlenose dolphin) to identify and classify cortical laminar and cytoarchitectonic structures in four distinct functional areas, including primary motor (M1), primary sensory (S1), primary visual (V1), and primary auditory (A1) cortices. The laminar and cytoarchitectonic organization of each of these cortical areas was similar among the three dolphin species. M1 was visualized as five-layer structure that included the molecular layer (layer I), external granular layer (layer II), external pyramidal layer (layer III), internal pyramidal layer (layer V), and fusiform layer (layer VI). The internal granular layer was absent. The cetacean sensory-related cortical areas S1, V1, and A1 were also found to have a five-layer organization comprising layers I, II, III, V and VI. In particular, A1 was characterized by the broadest layer I, layer II and developed band of pyramidal neurons in layers III (sublayers IIIa, IIIb and IIIc) and V. The patch organization consisting of the layer IIIb-pyramidal neurons was detected in the S1 and V1, but not in A1. The laminar patterns of V1 and S1 were similar, but the cytoarchitectonic structures of the two areas were different. V1 was characterized by a broader layer II than that of S1, and also contained the specialized pyramidal and multipolar stellate neurons in layers III and V. PMID:18625031

Analysis of the Angle of Maximal Stability and Flow Regime Transitions in Different Proportions of Bi-phasic Granular Matter Mixtures

NASA Astrophysics Data System (ADS)

Maquiling, Joel Tiu; Visaga, Shane Marie

This study investigates the dependence of the critical angle θc of stability on different mass ratios γ of layered bi-phasic granular matter mixtures and on the critical angle of its mono-disperse individual components. It also aims to investigate and explain regime transitions of granular matter flowing down a tilted rough inclined plane. Critical angles and flow regimes for a bi-phasic mixture of sago spheres and bi-phasic pepper mixture of fine powder and rough spheres were observed and measured using video analysis. The critical angles θc MD of mono-disperse granular matter and θc BP of biphasic granular matter mixtures were observed and compared. All types of flow regimes and a supramaximal critical angle of stability exist at mass ratio γ = 0.5 for all biphasic granular matter mixtures. The θc BP of sago spheres was higher than the θc MD of sago spheres. Moreover, the θc BP of the pepper mixture was in between the θc MD of fine pepper and θc MD of rough pepper spheres. Comparison of different granular material shows that θc MD is not simply a function of particle diameter but of particle roughness as well. Results point to a superposition mechanism of the critical angles of biphasic sphere mixtures.

Comparative cyto-histological study of needle tip aspirates and entry sites after intravitreal injection using different needle types

PubMed Central

Lytvynchuk, Lyubomyr; Sergienko, Andrij; Savytska, Iryna; Albert, Réka; Glittenberg, Carl; Binder, Susanne; Petrovski, Goran

2017-01-01

A comparison of the cellular content of needle tip aspirates and entry sites after transconjunctival intravitreal injection (IVI) using different needle types was performed. White outbred rats and human cadaver eyes were used for IVI by hypodermic 27 gauge (G) and 30G needles, and spinal anesthesia Pencan 27G needles. Aspiration of vitreous for quantitative morphological and cell cultivation analysis, as well as cyto-histological analysis of aspirates and entry sites were carried out. The most common cells in the aspirates from all needle types were conjunctival epithelial-, ciliary body non-pigmented epithelial- and sclerocyte-like cells and granular proteins. Crystallized vitreous specimens were present in each aspirate. The entry sites of hypodermic needles showed marked trauma in all wall layers of rat and human eyes accompanied by cellular destruction and hemorrhages. Pencan 27G needle caused less tissue trauma with partial reposition of sclerocytes. Transconjunctival IVIs with hypodermic 27G and 30G, and Pencan 27G needles result in trauma of all layers of the eyeball. The possible consequences of cellular content being cut and injected into the eye, as well as the entry site wound shape deserve future consideration and improvements. PMID:28692684

Molecular Pathology of Murine Ureteritis Causing Obstructive Uropathy with Hydronephrosis

PubMed Central

Ichii, Osamu; Otsuka, Saori; Namiki, Yuka; Hashimoto, Yoshiharu; Kon, Yasuhiro

2011-01-01

Primary causes of urinary tract obstruction that induces urine retention and results in hydronephrosis include uroliths, inflammation, and tumors. In this study, we analyzed the molecular pathology of ureteritis causing hydronephrosis in laboratory rodents. F2 progenies of C57BL/6 and DBA/2 mice were studied histopathologically and by comprehensive gene expression analysis of their ureters. Incidence of hydronephrosis was approximately 5% in F2 progenies. Histopathologically, this hydronephrosis was caused by stenosis of the proximal ureter, which showed fibrosis and papillary malformations of the proliferative epithelium with infiltrations of B-cell-dominated lymphocytes. Additionally, CD16-positive large granular leukocytes and eosinophils infiltrated from the ureteral mucosa to the muscular layer. Eosinophilic crystals were characteristically observed in the lumen of the ureter and the cytoplasm of large granular leukocytes, eosinophils, and transitional epithelial cells. Comprehensive gene profiling revealed remarkably elevated expression of genes associated with hyperimmune responses through activation of B cells in diseased ureters. Furthermore, diseased ureters showed dramatically higher gene expression of chitinase 3-like 3, known as Ym1, which is associated with formation both of adenomas in the transitional epithelium and of eosinophilic crystals in inflammatory conditions. The Ym1 protein was mainly localized to the cytoplasm of the transitional epithelium, infiltrated cells, and eosinophilic crystals in diseased ureters. We determined that the primary cause of hydronephrosis in F2 mice was ureteritis mediated by the local hyperimmune response with malformation of the transitional epithelium. Our data provide a novel molecular pathogenesis for elucidating causes of aseptic inflammation in human upper urinary tracts. PMID:22114694

Enhanced desalination performance of membrane capacitive deionization cells by packing the flow chamber with granular activated carbon.

PubMed

Bian, Yanhong; Yang, Xufei; Liang, Peng; Jiang, Yong; Zhang, Changyong; Huang, Xia

2015-11-15

A new design of membrane capacitive deionization (MCDI) cell was constructed by packing the cell's flow chamber with granular activated carbon (GAC). The GAC packed-MCDI (GAC-MCDI) delivered higher (1.2-2.5 times) desalination rates than the regular MCDI at all test NaCl concentrations (∼ 100-1000 mg/L). The greatest performance enhancement by packed GAC was observed when treating saline water with an initial NaCl concentration of 100 mg/L. Several different GAC materials were tested and they all exhibited similar enhancement effects. Comparatively, packing the MCDI's flow chamber with glass beads (GB; non-conductive) and graphite granules (GG; conductive but with lower specific surface area than GAC) resulted in inferior desalination performance. Electrochemical impedance spectroscopy (EIS) analysis showed that the GAC-MCDI had considerably smaller internal resistance than the regular MCDI (∼ 19.2 ± 1.2 Ω versus ∼ 1222 ± 15 Ω at 100 mg/L NaCl). The packed GAC also decreased the ionic resistance across the flow chamber (∼ 1.49 ± 0.05 Ω versus ∼ 1130 ± 12 Ω at 100 mg/L NaCl). The electric double layer (EDL) formed on the GAC surface was considered to store salt ions during electrosorption, and facilitate the ion transport in the flow chamber because of the higher ion conductivity in the EDLs than in the bulk solution, thereby enhancing the MCDI's desalination rate. Copyright © 2015 Elsevier Ltd. All rights reserved.

A Specific Nutrient Combination Attenuates the Reduced Expression of PSD-95 in the Proximal Dendrites of Hippocampal Cell Body Layers in a Mouse Model of Phenylketonuria.

PubMed

Bruinenberg, Vibeke M; van Vliet, Danique; Attali, Amos; de Wilde, Martijn C; Kuhn, Mirjam; van Spronsen, Francjan J; van der Zee, Eddy A

2016-03-26

The inherited metabolic disease phenylketonuria (PKU) is characterized by increased concentrations of phenylalanine in the blood and brain, and as a consequence neurotransmitter metabolism, white matter, and synapse functioning are affected. A specific nutrient combination (SNC) has been shown to improve synapse formation, morphology and function. This could become an interesting new nutritional approach for PKU. To assess whether treatment with SNC can affect synapses, we treated PKU mice with SNC or an isocaloric control diet and wild-type (WT) mice with an isocaloric control for 12 weeks, starting at postnatal day 31. Immunostaining for post-synaptic density protein 95 (PSD-95), a post-synaptic density marker, was carried out in the hippocampus, striatum and prefrontal cortex. Compared to WT mice on normal chow without SNC, PKU mice on the isocaloric control showed a significant reduction in PSD-95 expression in the hippocampus, specifically in the granular cell layer of the dentate gyrus, with a similar trend seen in the cornus ammonis 1 (CA1) and cornus ammonis 3 (CA3) pyramidal cell layer. No differences were found in the striatum or prefrontal cortex. PKU mice on a diet supplemented with SNC showed improved expression of PSD-95 in the hippocampus. This study gives the first indication that SNC supplementation has a positive effect on hippocampal synaptic deficits in PKU mice.

Nicotinic Acid Receptor Abnormalities in Human Skin Cancer: Implications for a Role in Epidermal Differentiation

PubMed Central

Bermudez, Yira; Benavente, Claudia A.; Meyer, Ralph G.; Coyle, W. Russell; Jacobson, Myron K.; Jacobson, Elaine L.

2011-01-01

Background Chronic UV skin exposure leads to epidermal differentiation defects in humans that can be largely restored by pharmacological doses of nicotinic acid. Nicotinic acid has been identified as a ligand for the human G-protein-coupled receptors GPR109A and GPR109B that signal through Gi-mediated inhibition of adenylyl cyclase. We have examined the expression, cellular distribution, and functionality of GPR109A/B in human skin and skin derived epidermal cells. Results Nicotinic acid increases epidermal differentiation in photodamaged human skin as judged by the terminal differentiation markers caspase 14 and filaggrin. Both GPR109A and GPR109B genes are transcribed in human skin and in epidermal keratinocytes, but expression in dermal fibroblasts is below limits of detection. Receptor transcripts are greatly over-expressed in squamous cell cancers. Receptor protein in normal skin is prominent from the basal through granular layers of the epidermis, with cellular localization more dispersive in the basal layer but predominantly localized at the plasma membrane in more differentiated epidermal layers. In normal human primary and immortalized keratinocytes, nicotinic acid receptors show plasma membrane localization and functional Gi-mediated signaling. In contrast, in a squamous cell carcinoma derived cell line, receptor protein shows a more diffuse cellular localization and the receptors are nearly non-functional. Conclusions The results of these studies justify future genetic and pharmacological intervention studies to define possible specific role(s) of nicotinic acid receptors in human skin homeostasis. PMID:21655214

Stretched exponentials and power laws in granular avalanching

NASA Astrophysics Data System (ADS)

Head, D. A.; Rodgers, G. J.

1999-02-01

We introduce a model for granular surface flow which exhibits both stretched exponential and power law avalanching over its parameter range. Two modes of transport are incorporated, a rolling layer consisting of individual particles and the overdamped, sliding motion of particle clusters. The crossover in behaviour observed in experiments on piles of rice is attributed to a change in the dominant mode of transport. We predict that power law avalanching will be observed whenever surface flow is dominated by clustered motion.

Cathepsin L and cystatin B gene expression discriminates immune cœlomic cells in the leech Theromyzon tessulatum

PubMed Central

Lefebvre, Christophe; Vandenbulcke, Franck; Bocquet, Béatrice; Tasiemski, Aurélie; Desmons, Annie; Verstraete, Mathilde; Salzet, Michel; Cocquerelle, Claude

2009-01-01

Previous studies evidenced that cystatin B-like gene is specifically expressed and induced in large circulating cœlomic cells following bacterial challenge in the leech Theromyzon tessulatum. In order to understand the role of that cysteine proteinase inhibitor during immune response, we investigated the existence of members of cathepsin family. We cloned a cathepsin L-like gene and studied its tissue distribution. Immunohistochemical studies using anti-cathepsin L and anti-cystatin B antibodies and ultrastructural results demonstrated the presence of three distinct cœlomic cell populations, (1) the chloragocytes which were initially defined as large cœlomocytes, (2) the granular amœbocytes, and (3) small cœlomic cells. Among those cells, while chloragocytes contain cystatin B and cathepsin L, granular amœbocytes do only contain cathepsin L and third cell population contains neither cathepsin nor inhibitor. Finally, results evidenced that cathepsin L immunopositive granular amœbocytes are chemoattracted to the site of injury and phagocyte bacteria. PMID:18177937

The specificity of immune priming in silkworm, Bombyx mori, is mediated by the phagocytic ability of granular cells.

PubMed

Wu, Gongqing; Li, Mei; Liu, Yi; Ding, Ying; Yi, Yunhong

2015-10-01

In the past decade, the phenomenon of immune priming was documented in many invertebrates in a large number of studies; however, in most of these studies, behavioral evidence was used to identify the immune priming. The underlying mechanism and the degree of specificity of the priming response remain unclear. We studied the mechanism of immune priming in the larvae of the silkworm, Bombyx mori, and analyzed the specificity of the priming response using two closely related Gram-negative pathogenic bacteria (Photorhabdus luminescens TT01 and P. luminescens H06) and one Gram-positive pathogenic bacterium (Bacillus thuringiensis HD-1). Primed with heat-killed bacteria, the B. mori larvae were more likely to survive subsequent homologous exposure (the identical bacteria used in the priming and in the subsequent challenge) than heterologous (different bacteria used in the priming and subsequent exposure) exposure to live bacteria. This result indicated that the B. mori larvae possessed a strong immune priming response and revealed a degree of specificity to TT01, H06 and HD-1 bacteria. The degree of enhanced immune protection was positively correlated with the level of phagocytic ability of the granular cells and the antibacterial activity of the cell-free hemolymph. Moreover, the granular cells of the immune-primed larvae increased the phagocytosis of a previously encountered bacterial strain compared with other bacteria. Thus, the enhanced immune protection of the B. mori larvae after priming was mediated by the phagocytic ability of the granular cells and the antibacterial activity of the hemolymph; the specificity of the priming response was primarily attributed to the phagocytosis of bacteria by the granular cells. Copyright © 2015 Elsevier Ltd. All rights reserved.

40 CFR 278.1 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... THE MANAGEMENT OF GRANULAR MINE TAILINGS (CHAT) IN ASPHALT CONCRETE AND PORTLAND CEMENT CONCRETE IN... purposes, including reducing the stress applied to the sub grade layer and providing drainage for the...

40 CFR 278.1 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-07-01

... THE MANAGEMENT OF GRANULAR MINE TAILINGS (CHAT) IN ASPHALT CONCRETE AND PORTLAND CEMENT CONCRETE IN... purposes, including reducing the stress applied to the sub grade layer and providing drainage for the...

40 CFR 278.1 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... THE MANAGEMENT OF GRANULAR MINE TAILINGS (CHAT) IN ASPHALT CONCRETE AND PORTLAND CEMENT CONCRETE IN... purposes, including reducing the stress applied to the sub grade layer and providing drainage for the...

40 CFR 278.1 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-07-01

... THE MANAGEMENT OF GRANULAR MINE TAILINGS (CHAT) IN ASPHALT CONCRETE AND PORTLAND CEMENT CONCRETE IN... purposes, including reducing the stress applied to the sub grade layer and providing drainage for the...

40 CFR 278.1 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-07-01

... THE MANAGEMENT OF GRANULAR MINE TAILINGS (CHAT) IN ASPHALT CONCRETE AND PORTLAND CEMENT CONCRETE IN... purposes, including reducing the stress applied to the sub grade layer and providing drainage for the...

A Mathematical Model of the Olfactory Bulb for the Selective Adaptation Mechanism in the Rodent Olfactory System.

PubMed

Soh, Zu; Nishikawa, Shinya; Kurita, Yuichi; Takiguchi, Noboru; Tsuji, Toshio

2016-01-01

To predict the odor quality of an odorant mixture, the interaction between odorants must be taken into account. Previously, an experiment in which mice discriminated between odorant mixtures identified a selective adaptation mechanism in the olfactory system. This paper proposes an olfactory model for odorant mixtures that can account for selective adaptation in terms of neural activity. The proposed model uses the spatial activity pattern of the mitral layer obtained from model simulations to predict the perceptual similarity between odors. Measured glomerular activity patterns are used as input to the model. The neural interaction between mitral cells and granular cells is then simulated, and a dissimilarity index between odors is defined using the activity patterns of the mitral layer. An odor set composed of three odorants is used to test the ability of the model. Simulations are performed based on the odor discrimination experiment on mice. As a result, we observe that part of the neural activity in the glomerular layer is enhanced in the mitral layer, whereas another part is suppressed. We find that the dissimilarity index strongly correlates with the odor discrimination rate of mice: r = 0.88 (p = 0.019). We conclude that our model has the ability to predict the perceptual similarity of odorant mixtures. In addition, the model also accounts for selective adaptation via the odor discrimination rate, and the enhancement and inhibition in the mitral layer may be related to this selective adaptation.

A Homozygous Missense Mutation in TGM5 Abolishes Epidermal Transglutaminase 5 Activity and Causes Acral Peeling Skin Syndrome

PubMed Central

Cassidy, Andrew J.; van Steensel, Maurice A. M.; Steijlen, Peter M.; van Geel, Michel; Velden, Jaap van der; Morley, Susan M.; Terrinoni, Alessandro; Melino, Gerry; Candi, Eleonora; McLean, W. H. Irwin

2005-01-01

Peeling skin syndrome is an autosomal recessive genodermatosis characterized by the shedding of the outer epidermis. In the acral form, the dorsa of the hands and feet are predominantly affected. Ultrastructural analysis has revealed tissue separation at the junction between the granular cells and the stratum corneum in the outer epidermis. Genomewide linkage analysis in a consanguineous Dutch kindred mapped the gene to 15q15.2 in the interval between markers D15S1040 and D15S1016. Two homozygous missense mutations, T109M and G113C, were found in TGM5, which encodes transglutaminase 5 (TG5), in all affected persons in two unrelated families. The mutation was present on the same haplotype in both kindreds, indicating a probable ancestral mutation. TG5 is strongly expressed in the epidermal granular cells, where it cross-links a variety of structural proteins in the terminal differentiation of the epidermis to form the cornified cell envelope. An established, in vitro, biochemical cross-linking assay revealed that, although T109M is not pathogenic, G113C completely abolishes TG5 activity. Three-dimensional modeling of TG5 showed that G113C lies close to the catalytic domain, and, furthermore, that this glycine residue is conserved in all known transglutaminases, which is consistent with pathogenicity. Other families with more-widespread peeling skin phenotypes lacked TGM5 mutations. This study identifies the first causative gene in this heterogeneous group of skin disorders and demonstrates that the protein cross-linking function performed by TG5 is vital for maintaining cell-cell adhesion between the outermost layers of the epidermis. PMID:16380904

A forgotten facial nerve tumour: granular cell tumour of the parotid and its implications for treatment.

PubMed

Lerut, B; Vosbeck, J; Linder, T E

2011-04-01

We present a rare case of a facial nerve granular cell tumour in the right parotid gland, in a 10-year-old boy. A parotid or neurogenic tumour was suspected, based on magnetic resonance imaging. Intra-operatively, strong adhesions to surrounding structures were found, and a midfacial nerve branch had to be sacrificed for complete tumour removal. Recent reports verify that granular cell tumours arise from Schwann cells of peripheral nerve branches. The rarity of this tumour within the parotid gland, its origin from peripheral nerves, its sometimes misleading imaging characteristics, and its rare presentation with facial weakness and pain all have considerable implications on the surgical strategy and pre-operative counselling. Fine needle aspiration cytology may confirm the neurogenic origin of this lesion. When resecting the tumour, the surgeon must anticipate strong adherence to the facial nerve and be prepared to graft, or sacrifice, certain branches of this nerve.

Spatiotemporal stick-slip phenomena in a coupled continuum-granular system

NASA Astrophysics Data System (ADS)

Ecke, Robert

In sheared granular media, stick-slip behavior is ubiquitous, especially at very small shear rates and weak drive coupling. The resulting slips are characteristic of natural phenomena such as earthquakes and well as being a delicate probe of the collective dynamics of the granular system. In that spirit, we developed a laboratory experiment consisting of sheared elastic plates separated by a narrow gap filled with quasi-two-dimensional granular material (bi-dispersed nylon rods) . We directly determine the spatial and temporal distributions of strain displacements of the elastic continuum over 200 spatial points located adjacent to the gap. Slip events can be divided into large system-spanning events and spatially distributed smaller events. The small events have a probability distribution of event moment consistent with an M - 3 / 2 power law scaling and a Poisson distributed recurrence time distribution. Large events have a broad, log-normal moment distribution and a mean repetition time. As the applied normal force increases, there are fractionally more (less) large (small) events, and the large-event moment distribution broadens. The magnitude of the slip motion of the plates is well correlated with the root-mean-square displacements of the granular matter. Our results are consistent with mean field descriptions of statistical models of earthquakes and avalanches. We further explore the high-speed dynamics of system events and also discuss the effective granular friction of the sheared layer. We find that large events result from stored elastic energy in the plates in this coupled granular-continuum system.

Density-wave fronts on the brink of wet granular condensation

NASA Astrophysics Data System (ADS)

Huang, Kai; Zippelius, Andreas; Sand lab @ University of Bayreuth Team

2017-11-01

From sand dunes to Faraday heaping, driven granular matter, i.e., large agglomeration of macroscopic particles, is rich pattern forming system. When a granular material is partially wet (e.g., wet sand on the beach), a different pattern forming scenario arises due to the cohesive particle-particle interactions. Here, we focus on the formation of density-wave fronts in an oscillated wet granular layer undergoing a gas-liquid-like transition. The threshold of the instability is governed by the amplitude of the vertical vibrations. Fronts, which are curved into a spiral shape, propagate coherently along the circular rim of the container with leading edges. They are stable beyond a critical distance from the container center. Based on the measurement of the critical distance and the rotation frequency, we propose a model for the pattern formation by considering the competition between the time scale for the collapse of cohesive particles and that of the energy injection resisting this process. Deutsche Forschungsgemeinschaft (Grant No. HU1939 4-1).

Ultrasonic investigation of granular materials subjected to compression and crushing.

PubMed

Gheibi, Amin; Hedayat, Ahmadreza

2018-07-01

Ultrasonic wave propagation measurement has been used as a suitable technique for studying the granular materials and investigating the soil fabric structure, the grain contact stiffness, frictional strength, and inter-particle contact area. Previous studies have focused on the variations of shear and compressional wave velocities with effective stress and void ratio, and lesser effort has been made in understanding the variation of amplitude and dominant frequency of transmitted compressional waves with deformation of soil packing. In this study, continuous compressional wave transmission measurements during compaction of unconsolidated quartz sand are used to investigate the impact of soil layer deformation on ultrasonic wave properties. The test setup consisted of a loading machine to apply constant loading rate to a sand layer (granular quartz) of 6 mm thickness compressed between two forcing blocks, and an ultrasonic wave measurement system to continuously monitor the soil layer during compression up to 48 MPa normal stress. The variations in compressional wave attributes such as wave velocity, transmitted amplitude, and dominant frequency were studied as a function of the applied normal stress and the measured normal strain as well as void ratio and particle size. An increasing trend was observed for P-wave velocity, transmitted amplitude and dominant frequency with normal stress. In specimen with the largest particle size (D 50  = 0.32 mm), the wave velocity, amplitude and dominant frequency were found to increase about 230%, 4700% and 320% as the normal stress reached the value of 48 MPa. The absolute values of transmitted wave amplitude and dominant frequency were greater for specimens with smaller particle sizes while the normalized values indicate an opposite trend. The changes in the transmitted amplitude were linked to the changes in the true contact area between the particles with a transitional point in the slope of normalized amplitude, coinciding with the yield stress of the granular soil layer. The amount of grain crushing as a result of increase in the normal stress was experimentally measured and a linear correlation was found between the degree of grain crushing and the changes in the normalized dominant frequency of compressional waves. Copyright © 2018 Elsevier B.V. All rights reserved.

Co-localization of glycine and gaba immunoreactivity in interneurons in Macaca monkey cerebellar cortex.

PubMed

Crook, J; Hendrickson, A; Robinson, F R

2006-09-15

Previous work demonstrates that the cerebellum uses glycine as a fast inhibitory neurotransmitter [Ottersen OP, Davanger S, Storm-Mathisen J (1987) Glycine-like immunoreactivity in the cerebellum of rat and Senegalese baboon, Papio papio: a comparison with the distribution of GABA-like immunoreactivity and with [3H]glycine and [3H]GABA uptake. Exp Brain Res 66(1):211-221; Ottersen OP, Storm-Mathisen J, Somogyi P (1988) Colocalization of glycine-like and GABA-like immunoreactivities in Golgi cell terminals in the rat cerebellum: a postembedding light and electron microscopic study. Brain Res 450(1-2):342-353; Dieudonne S (1995) Glycinergic synaptic currents in Golgi cells of the rat cerebellum. Proc Natl Acad Sci U S A 92:1441-1445; Dumoulin A, Triller A, Dieudonne S (2001) IPSC kinetics at identified GABAergic and mixed GABAergic and glycinergic synapses onto cerebellar Golgi cells. J Neurosci 21(16):6045-6057; Dugue GP, Dumoulin A, Triller A, Dieudonne S (2005) Target-dependent use of coreleased inhibitory transmitters at central synapses. J Neurosci 25(28):6490-6498; Zeilhofer HU, Studler B, Arabadzisz D, Schweizer C, Ahmadi S, Layh B, Bosl MR, Fritschy JM (2005) Glycinergic neurons expressing enhanced green fluorescent protein in bacterial artificial chromosome transgenic mice. J Comp Neurol 482(2):123-141]. In the rat cerebellum glycine is not released by itself but is released together with GABA by Lugaro cells onto Golgi cells [Dumoulin A, Triller A, Dieudonne S (2001) IPSC kinetics at identified GABAergic and mixed GABAergic and glycinergic synapses onto cerebellar Golgi cells. J Neurosci 21(16):6045-6057] and by Golgi cells onto unipolar brush and granule cells [Dugue GP, Dumoulin A, Triller A, Dieudonne S (2005) Target-dependent use of coreleased inhibitory transmitters at central synapses. J Neurosci 25(28):6490-6498]. Here we report, from immunolabeling evidence in Macaca cerebellum, that interneurons in the granular cell layer are glycine+ at a density of 120 cells/linear mm. Their morphology indicates that they include Golgi and Lugaro cell types with the majority containing both glycine and GABA or glutamic acid decarboxylase. These data are consistent with the proposal that, as in the rat cerebellum, these granular cell layer interneurons corelease glycine and GABA in the primate cerebellum. The patterns of labeling for glycine and GABA within Golgi and Lugaro cells also indicate that there are biochemical sub-types which are morphologically similar. Further, we find that glycine, GABA and glutamic acid decarboxylase identified candelabrum cells adjacent to the Purkinje cells which is the first time that this interneuron has been reported in primate cerebellar cortex. We propose that candelabrum cells, like the majority of Golgi and Lugaro cells, release both glycine and GABA.

Remodelling of three-dimensional organization of the nucleus during terminal keratinocyte differentiation in the epidermis

PubMed Central

Gdula, Michal R.; Poterlowicz, Krzysztof; Mardaryev, Andrei N.; Sharov, Andrey A.; Peng, Y.; Fessing, Michael Y.; Botchkarev, Vladimir A.

2014-01-01

The nucleus of epidermal keratinocytes is a complex and highly compartmentalized organelle, whose structure is markedly changed during terminal differentiation and transition of the genome from a transcriptionally active state seen in the basal and spinous epidermal cells to a fully inactive state in the keratinized cells of the cornified layer. Here, using multi-color confocal microscopy, followed by computational image analysis and mathematical modelling, we demonstrate that in normal mouse foot-pad epidermis transition of keratinocytes from basal epidermal layer to the granular layer is accompanied by marked differences in nuclear architecture and micro-environment including: i) decrease of the nuclear volume, ii) decrease in expression of the markers of transcriptionally-active chromatin; iii) internalization and decrease in the number of nucleoli; iv) increase in the number of pericentromeric heterochromatic clusters; v) increase in the frequency of associations between pericentromeric clusters, chromosomal territory 3, and nucleoli. These data suggest a role for nucleoli and pericentromeric heterochromatin clusters as organizers of nuclear micro-environment required for proper execution of gene expression programs in differentiating keratinocytes and provide important background information for further analyses of alterations in the topological genome organization seen in pathological skin conditions including disorders of epidermal differentiation and epidermal tumors. PMID:23407401

EMERGENCE OF GRANULAR-SIZED MAGNETIC BUBBLES THROUGH THE SOLAR ATMOSPHERE. II. NON-LTE CHROMOSPHERIC DIAGNOSTICS AND INVERSIONS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rodríguez, Jaime de la Cruz; Hansteen, Viggo; Ortiz, Ada

Magnetic flux emergence into the outer layers of the Sun is a fundamental mechanism for releasing energy into the chromosphere and the corona. In this paper, we study the emergence of granular-sized flux concentrations and the structuring of the corresponding physical parameters and atmospheric diagnostics in the upper photosphere and in the chromosphere. We make use of a realistic 3D MHD simulation of the outer layers of the Sun to study the formation of the Ca ii 8542 line. We also derive semi-empirical 3D models from non-LTE inversions of our observations. These models contain information on the line-of-sight stratifications ofmore » temperature, velocity, and the magnetic field. Our analysis explains the peculiar Ca ii 8542 Å profiles observed in the flux emerging region. Additionally, we derive detailed temperature and velocity maps describing the ascent of a magnetic bubble from the photosphere to the chromosphere. The inversions suggest that, in active regions, granular-sized bubbles emerge up to the lower chromosphere where the existing large-scale field hinders their ascent. We report hints of heating when the field reaches the chromosphere.« less

Experiments and characterization of low-frequency oscillations in a granular column

NASA Astrophysics Data System (ADS)

Oyarte Gálvez, Loreto; Rivas, Nicolás; van der Meer, Devaraj

2018-04-01

The behavior of a vertically vibrated granular bed is reminiscent of a liquid in that it exhibits many phenomena such as convection and Faraday-like surface waves. However, when the lateral dimensions of the bed are confined such that a quasi-one-dimensional geometry is formed, the only phenomena that remain are bouncing bed and the granular Leidenfrost effect. This permits the observation of the granular Leidenfrost state for a wide range of energy injection parameters and more specifically allows for a thorough characterization of the low-frequency oscillation (LFO) that is present in this state. In both experiments and particle simulations we determine the LFO frequency from the power spectral density of the center-of-mass signal of the grains, varying the amplitude and frequency of the driving, the particle diameter, and the number of layers in the system. We thus find that the LFO frequency (i) is inversely proportional to the fast inertial timescale and (ii) decorrelates with a typical decay time proportional to the slow dissipative timescale in the system. The latter is consistent with the view that the LFO is driven by the inherent noise that is present in the granular Leidenfrost state with a low number of particles.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lieou, Charles K. C.; Daub, Eric G.; Guyer, Robert A.

In this paper, we model laboratory earthquakes in a biaxial shear apparatus using the Shear-Transformation-Zone (STZ) theory of dense granular flow. The theory is based on the observation that slip events in a granular layer are attributed to grain rearrangement at soft spots called STZs, which can be characterized according to principles of statistical physics. We model lab data on granular shear using STZ theory and document direct connections between the STZ approach and rate-and-state friction. We discuss the stability transition from stable shear to stick-slip failure and show that stick slip is predicted by STZ when the applied shearmore » load exceeds a threshold value that is modulated by elastic stiffness and frictional rheology. Finally, we also show that STZ theory mimics fault zone dilation during the stick phase, consistent with lab observations.« less

Flow cytometric characterization of freshwater crayfish hemocytes for the examination of physiological status in wild and captive animals.

PubMed

Taylor, Sean; Landman, Michael J; Ling, Nicholas

2009-09-01

Enumeration of invertebrate hemocytes is a potentially powerful tool for the determination of physiological effects of extrinsic stressors, such as hypoxia, disease, and toxicant exposure. A detailed flow cytometric method of broad application was developed for the objective characterization and enumeration of the hemocytes of New Zealand freshwater crayfish Paranephrops planifrons for the purpose of physiological health assessment. Hemocyte populations were isolated by flow cytometric sorting based on differential light scatter properties followed by morphological characterization via light microscopy and software image analysis. Cells were identified as hyaline, semigranular, and granular hemocytes based on established invertebrate hemocyte classification. A characteristic decrease in nuclear size, an increase in granularity between the hyaline and granular cells, and the eccentric location of nuclei in granular cells were also observed. The granulocyte subpopulations were observed to possess varying degrees of granularity. The developed methodology was used to perform total and differential hemocyte counts from three lake populations and between wild and captive crayfish specimens. Differences in total and differential hemocyte counts were not observed among the wild populations. However, specimens held in captivity for 14 d exhibited a significant 63% reduction in total hemocyte count, whereas the relative hemocyte proportions remained the same. These results demonstrate the utility of this method for the investigation of subacute stressor effects in selected decapod crustaceans.

[Clinical and experimental study on effect of qinbal ointment in treating psoriasis in the active stage of blood-heat syndrome type].

PubMed

Xu, Jia; Zhang, Cang; Qu, Xing

2009-07-01

To investigate and compare the efficacy and safety of two kinds of Qinbai ointment prepared conventionally and finely (C-QBO and F-QBO) in treating psoriasis in the active stage of blood-heat syndrome type, and to observe their influences on vaginal epithelial cell mitosis, also on keratinization of caudal flakes in mice. Adopting randomized, single-blinded, controlled design, 93 patients administered orally with Liangxue Huoxue Decoction were randomized into three groups treated externally with C-QBO, F-QBO and white vaseline respectively, applied twice a day for 8 weeks. The safety was checked and the changes of modified psoriasis area severity index (PASI), as well as the conditions of skin lesions (size, erythema, infiltration, squama, and itching) and symptom improving time were compared. Experimental study 1: Mice were randomized into the model group, the C-QBO group, the F-QBO group and the blank group, 7 in each group. Their vaginal epithelial cell mitosis indices were compared after 3 days of treatment with corresponding remedies. Experimental study 2: Mice were randomized into the C-QBO group, the F-QBO group and the blank group, 7 in each group. After the mice had been treated with corresponding remedies for 28 days, the granular layer formation in their caudal scales was compared. The markedly effective rate was 63.3% (25/30) in the C-QBO group, 66.7% (20/30) in the F-QBO group, and 36.7% (11/30) in the control group. No statistical difference was showen between the two QBO treated groups (P > 0.05), but that in both of them was significantly different from that in the control group (P < 0.05). PASI scores lowered after treatment in all the three groups (P < 0.01), but the improvement in the two QBO groups was better than that in the control group (P < 0.05); the conditions of skin lesion were improved in all groups, but the improvements were more significant in the two QBO groups in terms of squama, infiltration and itching (P < 0.05), in aspects of improving time on erythema, infiltration and itching, especially the itching, F-QBO was superior to the C-QBO. Experimental study 1: The mitosis index in both QBO groups was lower than that in the blank group and the model group (P < 0.01). Experimental study 2: Number of scales with granular layer formation was higher in the two QBO groups than in the blank group (P < 0.01). C-QBO and F-QBO can effectively relieve the skin lesion of psoriasis patients in the active stage of blood-heat type, and they could also promote the formation of epithelial granular layer in the caudal scales of mice.

Slip-localization within confined gouge powder sheared at moderate to high slip-velocity

NASA Astrophysics Data System (ADS)

Reches, Zeev; Chen, Xiaofeng; Morgan, Chance; Madden, Andrew

2015-04-01

Slip along faults in the upper crust is always associated with comminution and formation of non-cohesive gouge powder that can be lithified to cataclasite. Typically, the fine-grained powders (grain-size < 1 micron) build a 1-10 cm thick inner-core of a fault-zone. The ubiquitous occurrence of gouge powder implies that gouge properties may control the dynamic weakening of faults. Testing these properties is the present objective. We built a Confined ROtary Cell, CROC, with a ring-shape, ~3 mm thick gouge chamber, with 62.5 and 81.2 mm of inner and outer diameters. The sheared powder is sealed by two sets of seals pressurized by nitrogen. In CROC, we can control the pore-pressure and to inject fluids, and to monitor CO2 and H2O concentration; in addition, we monitor the standard mechanical parameters (slip velocity, stresses, dilation, and temperature). We tested six types of granular materials (starting grain-size in microns): Talc (<250), Kasota dolomite (125-250), ooides grains (125-250), San Andreas fault zone powder (< 840), montmorillonite powder (1-2), kaolinite powder and gypsum. The experimental slip-velocity ranged 0.001-1 m/s, slip distances from a few tens of cm to tens of m, effective normal stress up to 6.1 MPa. The central ultra-microscopic (SEM) observation is that almost invariably the slip was localized along principal-slip-zone (PSZ) within the granular layer. Even though the starting material was loose, coarse granular material, the developed PSZ was cohesive, hard, smooth and shining. The PSZ is about 1 micron thick, and built of agglomerated, ultra-fine grains (20-50 nm) that were pulverized from the original granular material. We noted that PSZs of the different tested compositions display similar characteristics in terms of structure, grain size, and roughness. Further, we found striking similarities between PSZ in the granular samples and the PZS that developed along experimental faults made of solid rock that were sheared at similar conditions. The ultra-fine grains and extreme slip localization in these experiments are generally similar to ultra-cataclasites found in exhumed faults-zones, and the intensely pulverized gouge found in drilling across active faults.

The src-family protein-tyrosine kinase p59hck is located on the secretory granules in human neutrophils and translocates towards the phagosome during cell activation.

PubMed

Möhn, H; Le Cabec, V; Fischer, S; Maridonneau-Parini, I

1995-07-15

The src-family protein-tyrosine kinase p59hck is mainly expressed in neutrophils; however, its functional role in these cells is unknown. Several other src-family members are localized on secretory vesicles and have been proposed to regulate intracellular traffic. We have established here the subcellular localization of p59hck in human neutrophils. Immunoblotting of subcellular fractions showed that approx. 60% of the p59hck per cell is localized on the secretory granules; the other 40% is distributed equally between non-granular membranes and the cytosol. Immunofluorescence of neutrophils and HL60 cells suggests that the p59hck-positive granules are azurophil granules. Granular p59hck is highly susceptible to degradation by an azurophil-granule proteinase. Different forms of p59hck occur in the three subcellular compartments: a 61 kDa form is mainly found in the granules, a 59 kDa form is predominant in the non-granular membranes, whereas cytosolic p59hck migrates as a doublet at 63 kDa. During the process of phagocytosis-linked degranulation, induced by serum-opsonized zymosan in neutrophils or HL60 cells, granular p59hck translocates towards the phagosome. The subcellular localization of p59hck suggests that the enzyme could be involved in the regulation of the degranulation process.

Hsp70 in the atrial neuroendocrine units of the snail, Achatina fulica.

PubMed

Martynova, M G; Bystrova, O A; Shabelnikov, S V; Margulis, B A; Prokofjeva, D S

2007-04-01

Heat shock proteins (Hsps) are evolutionary conserved peptides well known as molecular chaperones and stress proteins. Elevated levels of extracellular Hsps in blood plasma have been observed during the stress responses and some diseases. Information on the cellular sources of extracellular Hsps and mechanisms regulating their release is still scanty. Here we showed the presence and localization of Hsp70 in the neuroendocrine system in the atrium of the snail, Achatina fulica. The occurrence of the peptide in snail atrium lysate was detected by Western blot analysis. Immunoperoxidase and immunogold staining demonstrated that Hsp70-immunoreactivity is mainly confined to the peculiar atrial neuroendocrine units which are formed by nerve fibers tightly contacted with large granular cells. Immunolabelling intensity differed in morphologically distinct types of secretory granules in the granular cells. The pictures of exocytosis of Hsp70-immunolabeled granules from the granular cells were observed. In nerve bundles, axon profiles with Hsp70-immunoreactive and those with non-immunoreactive neurosecretory granules were found. In addition, Hsp70-like material was also revealed in the granules of glia-interstitial cells that accompanied nerve fibers. Our findings provide an immuno-morphological basis for a role of Hsp70 in the functioning of the neuroendocrine system in the snail heart, and show that the atrial granular cells are a probable source of extracellular Hsp70 in the snail hemolymph.

Experimental study on the signs of particulate structures formation in annular geometry of rapid granular shear flows

NASA Astrophysics Data System (ADS)

Ritvanen, J.; Jalali, P.

2009-06-01

Rapid granular shear flow is a classical example in granular materials which exhibits both fluid-like and solid-like behaviors. Another interesting feature of rapid granular shear flows is the formation of ordered structures upon shearing. Certain amount of granular material, with uniform size distribution, is required to be loaded in the container in order to shear it under stable conditions. This work concerns the experimental study of rapid granular shear flows in annular Couette geometry. The flow is induced by continuous rotation of the plate over the top of the granular bed in an annulus. The compressive pressure, driving torque, instantaneous bed height from three symmetric locations and rotational speed of the shearing plate are measured. The annulus has a capacity of up to 15 kg of spherical steel balls of 3 mm in diameter. Rapid shear flow experiments are performed in one compressive force and rotation rate. The sensitivity of fluctuations is then investigated by different means through monodisperse packing. In this work, we present the results of the experiments showing how the flow properties depend on the amount of loaded granular material which is varied by small amounts between different experiments. The flow can exist in stable (fixed behavior) and unstable (time-dependent behavior) regimes as a function of the loaded material. We present the characteristics of flow to detect the formation of any additional structured layer in the annulus. As a result, an evolution graph for the bed height has been obtained as material is gradually added. This graph shows how the bed height grows when material increases. Using these results, the structure inside the medium can be estimated at extreme stable and unstable conditions.

Mechanistic design concepts for conventional flexible pavements

NASA Astrophysics Data System (ADS)

Elliott, R. P.; Thompson, M. R.

1985-02-01

Mechanical design concepts for convetional flexible pavement (asphalt concrete (AC) surface plus granular base/subbase) for highways are proposed and validated. The procedure is based on ILLI-PAVE, a stress dependent finite element computer program, coupled with appropriate transfer functions. Two design criteria are considered: AC flexural fatigue cracking and subgrade rutting. Algorithms were developed relating pavement response parameters (stresses, strains, deflections) to AC thickness, AC moduli, granular layer thickness, and subgrade moduli. Extensive analyses of the AASHO Road Test flexible pavement data are presented supporting the validity of the proposed concepts.

2D granular flows with the μ(I) rheology and side walls friction: A well-balanced multilayer discretization

NASA Astrophysics Data System (ADS)

Fernández-Nieto, E. D.; Garres-Díaz, J.; Mangeney, A.; Narbona-Reina, G.

2018-03-01

We present here numerical modelling of granular flows with the μ (I) rheology in confined channels. The contribution is twofold: (i) a model to approximate the Navier-Stokes equations with the μ (I) rheology through an asymptotic analysis; under the hypothesis of a one-dimensional flow, this model takes into account side walls friction; (ii) a multilayer discretization following Fernández-Nieto et al. (2016) [20]. In this new numerical scheme, we propose an appropriate treatment of the rheological terms through a hydrostatic reconstruction which allows this scheme to be well-balanced and therefore to deal with dry areas. Based on academic tests, we first evaluate the influence of the width of the channel on the normal profiles of the downslope velocity thanks to the multilayer approach that is intrinsically able to describe changes from Bagnold to S-shaped (and vice versa) velocity profiles. We also check the well-balanced property of the proposed numerical scheme. We show that approximating side walls friction using single-layer models may lead to strong errors. Secondly, we compare the numerical results with experimental data on granular collapses. We show that the proposed scheme allows us to qualitatively reproduce the deposit in the case of a rigid bed (i.e. dry area) and that the error made by replacing the dry area by a small layer of material may be large if this layer is not thin enough. The proposed model is also able to reproduce the time evolution of the free surface and of the flow/no-flow interface. In addition, it reproduces the effect of erosion for granular flows over initially static material lying on the bed. This is possible when using a variable friction coefficient μ (I) but not with a constant friction coefficient.

Dynamic Deformation and Collapse of Granular Columns

NASA Astrophysics Data System (ADS)

Uenishi, K.; Tsuji, K.; Doi, S.

2009-12-01

Large dynamic deformation of granular materials may be found in nature not only in the failure of slopes and cliffs — due to earthquakes, rock avalanches, debris flows and landslides — but also in earthquake faulting itself. Granular surface flows often consist of solid grains and intergranular fluid, but the effect of the fluid may be usually negligible because the volumetric concentration of grains is in many cases high enough for interparticle forces to dominate momentum transport. Therefore, the investigation of dry granular flow of a mass might assist in further understanding of the above mentioned geophysical events. Here, utilizing a high-speed digital video camera system, we perform a simple yet fully-controlled series of laboratory experiments related to the collapse of granular columns. We record, at an interval of some microseconds, the dynamic transient granular mass flow initiated by abrupt release of a tube that contains dry granular materials. The acrylic tube is partially filled with glass beads and has a cross-section of either a fully- or semi-cylindrical shape. Upon sudden removal of the tube, the granular solid may fragment under the action of its own weight and the particles spread on a rigid horizontal plane. This study is essentially the extension of the previous ones by Lajeunesse et al. (Phys. Fluids 2004) and Uenishi and Tsuji (JPGU 2008), but the striped layers of particles in a semi-cylindrical tube, newly introduced in this contribution, allow us to observe the precise particle movement inside the granular column: The development of slip lines inside the column and the movement of particles against each other can be clearly identified. The major controlling parameters of the spreading dynamics are the initial aspect ratio of the granular (semi-)cylindrical column, the frictional properties of the horizontal plane (substrate) and the size of beads. We show the influence of each parameter on the average flow velocity and final radius and height of the deposit, i.e., the fraction of granular mass mobilized by the flow, and the final shape of the deposit.

Layered Learning Design: Towards an Integration of Learning Design and Learning Object Perspectives

ERIC Educational Resources Information Center

Boyle, Tom

2010-01-01

The use of ICT to enhance teaching and learning depends on effective design, which operates at many levels of granularity from the small to the very large. This reflects the range of educational problems from course design down to the design of activities focused on specific learning objectives. For maximum impact these layers of design need to be…

Oxidative and cytotoxic stress induced by inorganic granular and fibrous particles.

PubMed

Helmig, Simone; Walter, Dirk; Putzier, Julia; Maxeiner, Hagen; Wenzel, Sibylle; Schneider, Joachim

2018-06-01

The hazards of granular and fibrous particles have been associated with the generation of reactive oxygen species (ROS), which in turn is often associated with physicochemical properties exhibited by these particles. In the present study, the ability of various types of fibrous and granular dusts to generate oxidative stress, and their cytotoxicity, was investigated. Biopersistent granular dusts employed in the present study included micro‑ and nanosized titanium dioxide with rutile or anatase crystal structure modifications. Additionally, glass fibres, chrysotile and crocidolite asbestos representative of fibrous dust were selected. Detailed characterisation of particles was performed using scanning electron microscopy, and the effect of exposure to these particles on cell viability and intracellular ROS generation was assessed by PrestoBlue and 2',7'‑dichlorofluorescein assays, respectively. A549 human lung epithelial adenocarcinoma cells were exposed to increasing concentrations (0.1‑10 µg/cm2) of particles and fibres for 24 h. Subsequently, the gene expression of X‑linked inhibitor of apoptosis (XIAP), superoxide dismutase (SOD)1 and SOD2 were analysed by reverse transcription‑quantitative polymerase chain reaction. All investigated granular particles induce ROS production in A549 lung carcinoma cells within 24 h. Hematite increased ROS production in a dose‑dependent manner. A concentration of >1 µg/cm2 TiO2 na with its disordered surface, demonstrated the greatest ability to generate ROS. Therefore, the crystalline surface structure of the particle may be considered as a determinant of the extent of ROS induction by the particle. Fibrous particle compared with granular particles were associated with a lower ability to generate ROS. Glass fibres did not significantly increase ROS production in A549 cells, but elevated gene expression of SOD2 was observed. The results demonstrated that in general, the ability of particles to generate ROS depends on their number and crystal phase. Therefore, the present study helps to understand the cause of particle toxicity.

Simulating Regoliths in a Microgravity Environment

NASA Astrophysics Data System (ADS)

Murdoch, N.; Rozitis, B.; Green, S. F.; Michel, P.; Losert, W.; de Lophem, T. L.

2011-10-01

The dynamics of granular materials are involved in the evolution of solid planets and small bodies in our Solar System, whose surfaces are generally covered with regolith. An understanding of granular dynamics appears also to be critical for the design and/or operations of landers, sampling devices and rovers to be included in space missions. The AstEx experiment uses a microgravity modified Taylor-Couette shear cell to investigate granular motion caused by shear and shear reversal forces under the microgravity conditions of parabolic flight. The results will lead to a greater understanding of the mechanical response of granular materials subject to external forces in varying gravitational environments.

Onset of Tlx-3 expression in the chick cerebellar cortex correlates with the morphological development of fissures and delineates a posterior transverse boundary.

PubMed

Logan, Cairine; Millar, Cassie; Bharadia, Vinay; Rouleau, Katherine

2002-06-24

Recent studies have shown that the mammalian cerebellar cortex can be subdivided into a reproducible array of zones and stripes. In particular, discontinuous patterns of gene expression together with mutational analysis suggest that there are at least four distinct transverse zones along the rostrocaudal axis in mouse: the anterior zone (lobules I-V), the central zone (lobules VI and VII), the posterior zone (lobules VIII and IX), and the nodular zone (lobule X). Here we show that the divergent homeobox-containing transcription factor, Tlx- 3 (also known as Hox11L2 or Rnx) is transiently expressed in external granule cells in a distinct transverse domain of the developing chick cerebellar cortex. Expression is first detected at Hamburger and Hamilton (HH) stage 35. Interestingly, Tlx-3 mRNA expression is initially confined to, and coincident with, the morphological development of fissures. Slightly later, at HH stage 38, expression extends throughout the developing external granular layer (EGL) of lobules I-IXab. Notably, no Tlx-3 expression was detected in lobules IXc and X at any developmental time point examined. Expression is noticeably stronger in nonproliferating cells located in the deep layer of the EGL. Tlx-3 expression is downregulated as granule cells migrate inward to form the internal granule layer and is undetectable shortly after birth. These results suggest that Tlx-3 is expressed as granule cells become postmitotic and suggest that Tlx-3 may play a role in the differentiation of distinct neuronal populations in the cerebellum. Copyright 2002 Wiley-Liss, Inc.

Ulex europaeus I and glycine max bind to the human olfactory bulb.

PubMed

Nagao, M; Oka, N; Kamo, H; Akiguchi, I; Kimura, J

1993-12-24

The distribution of binding sites for the fucose-selective lectin Ulex europaeus I and the terminal N-acetylgalactosamine-selective lectin glycine max in the human olfactory bulb were studied. These lectins bound to primary olfactory axons in the olfactory nerve layer and the glomerular layer. They also bound to fibers located in the deeper layers such as the external plexiform layer and the granular layer. Furthermore they projected to the olfactory stalk but not in the cerebrum. The deeper projections of the lectin binding fibers may affect the function of the olfactory bulb in humans.

Characterization of Uterine Granular Cell Tumors in B6C3F1 Mice: A Histomorphologic, Immunohistochemical, and Ultrastructural Study

PubMed Central

Veit, A. C.; Painter, J. T.; Miller, R. A.; Hardisty, J. F.; Dixon, D.

2009-01-01

The granular cell tumor is most often a benign neoplasm of uncertain origin. Four uterine granular cell tumors in control and treated female B6C3F1 mice were identified in chronic studies at the National Toxicology Program. Two tumors occurred in untreated control animals and 2 in treated animals receiving different compounds. Tissue sections were evaluated histologically and stained with hematoxylin and eosin, periodic acid–Schiff with diastase resistance, Masson’s trichrome, toluidine blue, phosphotungstic acid–hematoxylin, and stained immunohistochemically with a panel of antibodies to muscle (desmin, alpha smooth muscle actin), neural (S-100, neuron specific enolase), epithelial (wide-spectrum cytokeratin), and macrophage (F4/80) markers. The main histomorphologic feature of tumor cells was the presence of abundant cytoplasmic eosinophilic granules that stained positive for periodic acid–Schiff with diastase resistance. Tumors varied in appearance and were comprised of sheets and nests of round to polygonal cells with distinct borders. Nuclei were hyperchromatic, pleomorphic, and centrally to eccentrically located and often contained single nucleoli. Occasional multinucleated giant cells were observed. Tumors were pale pink and homogeneous with trichrome stain and negative with toluidine blue. Three tumors had positive to weakly positive immunoreactivity for desmin, and 1 was positive for alpha smooth muscle actin. Expression of S-100, wide-spectrum cytokeratin, and neuron-specific enolase was negative for all tumors. Ultrastructurally, prominent electron-dense cytoplasmic granules were abundant and contained secondary lysosomes with heterogeneous lysosomal contents. The characteristics of these uterine granular cell tumors were suggestive of a myogenic origin. PMID:18725470

Cortical and thalamic contributions to response dynamics across layers of the primary somatosensory cortex during tactile discrimination

PubMed Central

Pais-Vieira, Miguel; Kunicki, Carolina; Tseng, Po-He; Martin, Joel; Lebedev, Mikhail

2015-01-01

Tactile information processing in the rodent primary somatosensory cortex (S1) is layer specific and involves modulations from both thalamocortical and cortico-cortical loops. However, the extent to which these loops influence the dynamics of the primary somatosensory cortex while animals execute tactile discrimination remains largely unknown. Here, we describe neural dynamics of S1 layers across the multiple epochs defining a tactile discrimination task. We observed that neuronal ensembles within different layers of the S1 cortex exhibited significantly distinct neurophysiological properties, which constantly changed across the behavioral states that defined a tactile discrimination. Neural dynamics present in supragranular and granular layers generally matched the patterns observed in the ventral posterior medial nucleus of the thalamus (VPM), whereas the neural dynamics recorded from infragranular layers generally matched the patterns from the posterior nucleus of the thalamus (POM). Selective inactivation of contralateral S1 specifically switched infragranular neural dynamics from POM-like to those resembling VPM neurons. Meanwhile, ipsilateral M1 inactivation profoundly modulated the firing suppression observed in infragranular layers. This latter effect was counterbalanced by contralateral S1 block. Tactile stimulus encoding was layer specific and selectively affected by M1 or contralateral S1 inactivation. Lastly, causal information transfer occurred between all neurons in all S1 layers but was maximal from infragranular to the granular layer. These results suggest that tactile information processing in the S1 of awake behaving rodents is layer specific and state dependent and that its dynamics depend on the asynchronous convergence of modulations originating from ipsilateral M1 and contralateral S1. PMID:26180115

Intercomparison of granular stress and turbulence models for unidirectional sheet flow applications

NASA Astrophysics Data System (ADS)

Chauchat, J.; Cheng, Z.; Hsu, T. J.

2016-12-01

The intergranular stresses are one of the key elements in two-phase sediment transport models. There are two main existing approaches, the kinetic theory of granular flows (Jenkins and Hanes, 1998; Hsu et al., 2004) and the phenomenological rheology such as the one proposed by Bagnold (Hanes and Bowen, 1985) or the μ(I) dense granular flow rheology (Revil-Baudard and Chauchat, 2013). Concerning the turbulent Reynolds stress, mixing length and k-ɛ turbulence models have been validated by previous studies (Revil-Baudard and Chauchat, 2013; Hsu et al., 2004). Recently, sedFoam was developed based on kinetic theory of granular flows and k-ɛ turbulence models (Cheng and Hsu, 2014). In this study, we further extended sedFoam by implementing the mixing length and the dense granular flow rheology by following Revil-Baudard and Chauchat (2013). This allows us to objectively compare the different combinations of intergranular stresses (kinetic theory or the dense granular flow rheology) and turbulence models (mixing length or k-ɛ) under unidirectional sheet flow conditions. We found that the calibrated mixing length and k-ɛ models predicts similar velocity and concentration profiles. The differences observed between the kinetic theory and the dense granular flow rheology requires further investigation. In particular, we hypothesize that the extended kinetic theory proposed by Berzi (2011) would probably improve the existing combination of the kinetic theory with a simple Coulomb frictional model in sedFoam. A semi-analytical solution proposed by Berzi and Fraccarollo(2013) for sediment transport rate and sheet layer thickness versus the Shields number is compared with the results obtained by using the dense granular flow rheology and the mixing length model. The results are similar which demonstrate that both the extended kinetic theory and the dense granular flow rheology can be used to model intergranular stresses under sheet flow conditions.

Origin, lineage and function of cerebellar glia.

PubMed

Buffo, Annalisa; Rossi, Ferdinando

2013-10-01

The glial cells of the cerebellum, and particularly astrocytes and oligodendrocytes, are characterized by a remarkable phenotypic variety, in which highly peculiar morphological features are associated with specific functional features, unique among the glial cells of the entire CNS. Here, we provide a critical report about the present knowledge of the development of cerebellar glia, including lineage relationships between cerebellar neurons, astrocytes and oligodendrocytes, the origins and the genesis of the repertoire of glial types, and the processes underlying their acquisition of mature morphological and functional traits. In parallel, we describe and discuss some fundamental roles played by specific categories of glial cells during cerebellar development. In particular, we propose that Bergmann glia exerts a crucial scaffolding activity that, together with the organizing function of Purkinje cells, is necessary to achieve the normal pattern of foliation and layering of the cerebellar cortex. Moreover, we discuss some of the functional tasks of cerebellar astrocytes and oligodendrocytes that are distinctive of cerebellar glia throughout the CNS. Notably, we report about the regulation of synaptic signalling in the molecular and granular layer mediated by Bergmann glia and parenchymal astrocytes, and the functional interaction between oligodendrocyte precursor cells and neurons. On the whole, this review provides an extensive overview of the available literature and some novel insights about the origin and differentiation of the variety of cerebellar glial cells and their function in the developing and mature cerebellum. Copyright © 2013 Elsevier Ltd. All rights reserved.

Complex relationship between BOLD-fMRI and electrophysiological signals in different olfactory bulb layers.

PubMed

Li, Bo; Gong, Ling; Wu, Ruiqi; Li, Anan; Xu, Fuqiang

2014-07-15

Blood oxygenation level dependent functional magnetic resonance imaging (BOLD-fMRI), one of the most powerful technologies in neuroscience, measures neural activity indirectly. Therefore, systematic correlation of BOLD signals with other neural activity measurements is critical to understanding and then using the technology. Numerous studies have revealed that the BOLD signal is determined by many factors and is better correlated with local field potentials (LFP) than single/multiple unit firing. The relationship between BOLD and LFP signals under higher spatial resolution is complex and remains unclear. Here, changes of BOLD and LFP signals in the glomerular (GL), mitral cell (MCL), and granular cell layers (GCL) of the olfactory bulb were evoked by odor stimulation and sequentially acquired using high-resolution fMRI and electrode array. The experimental results revealed a rather complex relationship between BOLD and LFP signals. Both signal modalities were increased layer-dependently by odor stimulation, but the orders of signal intensity were significantly different: GL>MCL>GCL and GCL>GL>MCL for BOLD and LFP, respectively. During odor stimulation, the temporal features of LFPs were similar for a given band in different layers, but different for different frequency bands in a given layer. The BOLD and LFP signals in the low gamma frequency band correlated the best. This study provides new evidence for the consistency between structure and function in understanding the neurophysiological basis of BOLD signals, but also reminds that caution must be taken in interpreting of BOLD signals in regard to neural activity. Copyright © 2014 Elsevier Inc. All rights reserved.

Installing Mechanics of Granular Materials (MGM) Experiment Test Cell

NASA Technical Reports Server (NTRS)

1996-01-01

Astronaut Carl Walz installs Mechanics of Granular Materials (MGM) test cell on STS-79. Sand and soil grains have faces that can cause friction as they roll and slide against each other, or even cause sticking and form small voids between grains. This complex behavior can cause soil to behave like a liquid under certain conditions such as earthquakes or when powders are handled in industrial processes. Mechanics of Granular Materials (MGM) experiments aboard the Space Shuttle use the microgravity of space to simulate this behavior under conditons that carnot be achieved in laboratory tests on Earth. MGM is shedding light on the behavior of fine-grain materials under low effective stresses. Applications include earthquake engineering, granular flow technologies (such as powder feed systems for pharmaceuticals and fertilizers), and terrestrial and planetary geology. Nine MGM specimens have flown on two Space Shuttle flights. Another three are scheduled to fly on STS-107. The principal investigator is Stein Sture of the University of Colorado at Boulder. Credit: NASA/John Space Center

Granular Cell Tumor of the Common Hepatic Duct as an Unusual Cause of Jaundice in a Hepatitis C Patient.

PubMed

Chopade, Tripti R; Smith, Colin L; Maley, Warren R; Siddiqui, Ali A; Sass, David A

2016-01-01

A 33-year-old woman with a history of intravenous cocaine abuse presented with fatigue, nausea, and jaundice. Serologic testing revealed a positive hepatitis C virus (HCV) antibody and HCV RNA. Ultrasound and magnetic resonance imaging/magnetic resonance cholangiopancreatography showed a partially obstructing lesion in the common hepatic duct, which was confirmed by endoscopic retrograde cholangiopancreatography. Surgical excision revealed a granular cell tumor of the common hepatic duct, with immunohistochemical staining of tumor cells positive for S-100.

A test of the double-shearing model of flow for granular materials

USGS Publications Warehouse

Savage, J.C.; Lockner, D.A.

1997-01-01

The double-shearing model of flow attributes plastic deformation in granular materials to cooperative slip on conjugate Coulomb shears (surfaces upon which the Coulomb yield condition is satisfied). The strict formulation of the double-shearing model then requires that the slip lines in the material coincide with the Coulomb shears. Three different experiments that approximate simple shear deformation in granular media appear to be inconsistent with this strict formulation. For example, the orientation of the principal stress axes in a layer of sand driven in steady, simple shear was measured subject to the assumption that the Coulomb failure criterion was satisfied on some surfaces (orientation unspecified) within the sand layer. The orientation of the inferred principal compressive axis was then compared with the orientations predicted by the double-shearing model. The strict formulation of the model [Spencer, 1982] predicts that the principal stress axes should rotate in a sense opposite to that inferred from the experiments. A less restrictive formulation of the double-shearing model by de Josselin de Jong [1971] does not completely specify the solution but does prescribe limits on the possible orientations of the principal stress axes. The orientations of the principal compression axis inferred from the experiments are probably within those limits. An elastoplastic formulation of the double-shearing model [de Josselin de Jong, 1988] is reasonably consistent with the experiments, although quantitative agreement was not attained. Thus we conclude that the double-shearing model may be a viable law to describe deformation of granular materials, but the macroscopic slip surfaces will not in general coincide with the Coulomb shears.

Stochastic transitions and jamming in granular pipe flow

NASA Astrophysics Data System (ADS)

Brand, Samuel; Ball, Robin C.; Nicodemi, Mario

2011-03-01

We study a model granular suspension driven down a channel by an embedding fluid via computer simulations. We characterize the different system flow regimes and the stochastic nature of the transitions between them. For packing fractions below a threshold ϕm, granular flow is disordered and exhibits an Ostwald-de Waele-type power-law shear-stress constitutive relation. Above ϕm, two asymptotic states exist; disordered flow can persist indefinitely, yet, in a fraction of samples, the system self-organizes in an ordered form of flow where grains move in parallel ordered layers. In the latter regime, the Ostwald-de Waele relationship breaks down and a nearly solid plug appears in the center, with linear shear regions at the boundaries. Above a higher threshold ϕg, an abrupt jamming transition is observed if ordering is avoided.

Stratification, segregation, and mixing of granular materials in quasi-two-dimensional bounded heaps.

PubMed

Fan, Yi; Boukerkour, Youcef; Blanc, Thibault; Umbanhowar, Paul B; Ottino, Julio M; Lueptow, Richard M

2012-11-01

Segregation and mixing of granular mixtures during heap formation has important consequences in industry and agriculture. This research investigates three different final particle configurations of bidisperse granular mixtures--stratified, segregated and mixed--during filling of quasi-two-dimensional silos. We consider a large number and wide range of control parameters, including particle size ratio, flow rate, system size, and heap rise velocity. The boundary between stratified and unstratified states is primarily controlled by the two-dimensional flow rate, with the critical flow rate for the transition depending weakly on particle size ratio and flowing layer length. In contrast, the transition from segregated to mixed states is controlled by the rise velocity of the heap, a control parameter not previously considered. The critical rise velocity for the transition depends strongly on the particle size ratio.

Localization of the cannabinoid CB1 receptor and the 2-AG synthesizing (DAGLα) and degrading (MAGL, FAAH) enzymes in cells expressing the Ca2+-binding proteins calbindin, calretinin, and parvalbumin in the adult rat hippocampus

PubMed Central

Rivera, Patricia; Arrabal, Sergio; Cifuentes, Manuel; Grondona, Jesús M.; Pérez-Martín, Margarita; Rubio, Leticia; Vargas, Antonio; Serrano, Antonia; Pavón, Francisco J.; Suárez, Juan; Rodríguez de Fonseca, Fernando

2014-01-01

The retrograde suppression of the synaptic transmission by the endocannabinoid sn-2-arachidonoylglycerol (2-AG) is mediated by the cannabinoid CB1 receptors and requires the elevation of intracellular Ca2+ and the activation of specific 2-AG synthesizing (i.e., DAGLα) enzymes. However, the anatomical organization of the neuronal substrates that express 2-AG/CB1 signaling system-related molecules associated with selective Ca2+-binding proteins (CaBPs) is still unknown. For this purpose, we used double-label immunofluorescence and confocal laser scanning microscopy for the characterization of the expression of the 2-AG/CB1 signaling system (CB1 receptor, DAGLα, MAGL, and FAAH) and the CaBPs calbindin D28k, calretinin, and parvalbumin in the rat hippocampus. CB1, DAGLα, and MAGL labeling was mainly localized in fibers and neuropil, which were differentially organized depending on the hippocampal CaBPs-expressing cells. CB+1 fiber terminals localized in all hippocampal principal cell layers were tightly attached to calbindin+ cells (granular and pyramidal neurons), and calretinin+ and parvalbumin+ interneurons. DAGLα neuropil labeling was selectively found surrounding calbindin+ principal cells in the dentate gyrus and CA1, and in the calretinin+ and parvalbumin+ interneurons in the pyramidal cell layers of the CA1/3 fields. MAGL+ terminals were only observed around CA1 calbindin+ pyramidal cells, CA1/3 calretinin+ interneurons and CA3 parvalbumin+ interneurons localized in the pyramidal cell layers. Interestingly, calbindin+ pyramidal cells expressed FAAH specifically in the CA1 field. The identification of anatomically related-neuronal substrates that expressed 2-AG/CB1 signaling system and selective CaBPs should be considered when analyzing the cannabinoid signaling associated with hippocampal functions. PMID:25018703

Sinking during earthquakes: Critical acceleration criteria control drained soil liquefaction

NASA Astrophysics Data System (ADS)

Clément, C.; Toussaint, R.; Stojanova, M.; Aharonov, E.

2018-02-01

This article focuses on liquefaction of saturated granular soils, triggered by earthquakes. Liquefaction is defined here as the transition from a rigid state, in which the granular soil layer supports structures placed on its surface, to a fluidlike state, in which structures placed initially on the surface sink to their isostatic depth within the granular layer. We suggest a simple theoretical model for soil liquefaction and show that buoyancy caused by the presence of water inside a granular medium has a dramatic influence on the stability of an intruder resting at the surface of the medium. We confirm this hypothesis by comparison with laboratory experiments and discrete-element numerical simulations. The external excitation representing ground motion during earthquakes is simulated via horizontal sinusoidal oscillations of controlled frequency and amplitude. In the experiments, we use particles only slightly denser than water, which as predicted theoretically increases the effect of liquefaction and allows clear depth-of-sinking measurements. In the simulations, a micromechanical model simulates grains using molecular dynamics with friction between neighbors. The effect of the fluid is captured by taking into account buoyancy effects on the grains when they are immersed. We show that the motion of an intruder inside a granular medium is mainly dependent on the peak acceleration of the ground motion and establish a phase diagram for the conditions under which liquefaction happens, depending on the soil bulk density, friction properties, presence of water, and peak acceleration of the imposed large-scale soil vibrations. We establish that in liquefaction conditions, most cases relax toward an equilibrium position following an exponential in time. We also show that the equilibrium position itself, for most liquefaction regimes, corresponds to the isostatic equilibrium of the intruder inside a medium of effective density. The characteristic time to relaxation is shown to be essentially a function of the peak ground velocity.

Sinking during earthquakes: Critical acceleration criteria control drained soil liquefaction.

PubMed

Clément, C; Toussaint, R; Stojanova, M; Aharonov, E

2018-02-01

This article focuses on liquefaction of saturated granular soils, triggered by earthquakes. Liquefaction is defined here as the transition from a rigid state, in which the granular soil layer supports structures placed on its surface, to a fluidlike state, in which structures placed initially on the surface sink to their isostatic depth within the granular layer. We suggest a simple theoretical model for soil liquefaction and show that buoyancy caused by the presence of water inside a granular medium has a dramatic influence on the stability of an intruder resting at the surface of the medium. We confirm this hypothesis by comparison with laboratory experiments and discrete-element numerical simulations. The external excitation representing ground motion during earthquakes is simulated via horizontal sinusoidal oscillations of controlled frequency and amplitude. In the experiments, we use particles only slightly denser than water, which as predicted theoretically increases the effect of liquefaction and allows clear depth-of-sinking measurements. In the simulations, a micromechanical model simulates grains using molecular dynamics with friction between neighbors. The effect of the fluid is captured by taking into account buoyancy effects on the grains when they are immersed. We show that the motion of an intruder inside a granular medium is mainly dependent on the peak acceleration of the ground motion and establish a phase diagram for the conditions under which liquefaction happens, depending on the soil bulk density, friction properties, presence of water, and peak acceleration of the imposed large-scale soil vibrations. We establish that in liquefaction conditions, most cases relax toward an equilibrium position following an exponential in time. We also show that the equilibrium position itself, for most liquefaction regimes, corresponds to the isostatic equilibrium of the intruder inside a medium of effective density. The characteristic time to relaxation is shown to be essentially a function of the peak ground velocity.

Diagnostic implications of IDH1-R132H and OLIG2 expression patterns in rare and challenging glioblastoma variants.

PubMed

Joseph, Nancy M; Phillips, Joanna; Dahiya, Sonika; M Felicella, Michelle; Tihan, Tarik; Brat, Daniel J; Perry, Arie

2013-03-01

Recent work has demonstrated that nearly all diffuse gliomas display nuclear immunoreactivity for the bHLH transcription factor OLIG2, and the R132H mutant isocitrate dehydrogenase 1 (IDH1) protein is expressed in the majority of diffuse gliomas other than primary glioblastoma. However, these antibodies have not been widely applied to rarer glioblastoma variants, which can be diagnostically challenging when the astrocytic features are subtle. We therefore surveyed the expression patterns of OLIG2 and IDH1 in 167 non-conventional glioblastomas, including 45 small cell glioblastomas, 45 gliosarcomas, 34 glioblastomas with primitive neuroectodermal tumor-like foci (PNET-like foci), 23 with an oligodendroglial component, 11 granular cell glioblastomas, and 9 giant cell glioblastomas. OLIG2 was strongly expressed in all glioblastomas with oligodendroglial component, 98% of small cell glioblastomas, and all granular cell glioblastomas, the latter being particularly helpful in ruling out macrophage-rich lesions. In 74% of glioblastomas with PNET-like foci, OLIG2 expression was retained in the PNET-like foci, providing a useful distinction from central nervous system PNETs. The glial component of gliosarcomas was OLIG2 positive in 93% of cases, but only 14% retained focal expression in the sarcomatous component; as such this marker would not reliably distinguish these from pure sarcoma in most cases. OLIG2 was expressed in 67% of giant cell glioblastomas. IDH1 was expressed in 55% of glioblastomas with oligodendroglial component, 15% of glioblastomas with PNET-like foci, 7% of gliosarcomas, and none of the small cell, granular cell, or giant cell glioblastomas. This provides further support for the notion that most glioblastomas with oligodendroglial component are secondary, while small cell glioblastomas, granular cell glioblastomas, and giant cell glioblastomas are primary variants. Therefore, in one of the most challenging differential diagnoses, IDH1 positivity could provide strong support for glioblastoma with oligodendroglial component, while essentially excluding small cell glioblastoma.

An experimental study of the elastic theory for granular flows

NASA Astrophysics Data System (ADS)

Guo, Tongtong; Campbell, Charles S.

2016-08-01

This paper reports annular shear cell measurements granular flows with an eye towards experimentally confirming the flow regimes laid out in the elastic theory of granular flow. Tests were carried out on four different kinds of plastic spherical particles under both constant volume flows and constant applied stress flows. In particular, observations were made of the new regime in that model, the elastic-inertial regime, and the predicted transitions between the elastic-inertial and both the elastic-quasistatic and pure inertial regimes.

Integrated plasticity at inhibitory and excitatory synapses in the cerebellar circuit.

PubMed

Mapelli, Lisa; Pagani, Martina; Garrido, Jesus A; D'Angelo, Egidio

2015-01-01

The way long-term potentiation (LTP) and depression (LTD) are integrated within the different synapses of brain neuronal circuits is poorly understood. In order to progress beyond the identification of specific molecular mechanisms, a system in which multiple forms of plasticity can be correlated with large-scale neural processing is required. In this paper we take as an example the cerebellar network, in which extensive investigations have revealed LTP and LTD at several excitatory and inhibitory synapses. Cerebellar LTP and LTD occur in all three main cerebellar subcircuits (granular layer, molecular layer, deep cerebellar nuclei) and correspondingly regulate the function of their three main neurons: granule cells (GrCs), Purkinje cells (PCs) and deep cerebellar nuclear (DCN) cells. All these neurons, in addition to be excited, are reached by feed-forward and feed-back inhibitory connections, in which LTP and LTD may either operate synergistically or homeostatically in order to control information flow through the circuit. Although the investigation of individual synaptic plasticities in vitro is essential to prove their existence and mechanisms, it is insufficient to generate a coherent view of their impact on network functioning in vivo. Recent computational models and cell-specific genetic mutations in mice are shedding light on how plasticity at multiple excitatory and inhibitory synapses might regulate neuronal activities in the cerebellar circuit and contribute to learning and memory and behavioral control.

Differential settlement of a geosynthetic reinforced soil abutment : full-scale investigation.

DOT National Transportation Integrated Search

2015-05-01

The Geosynthetic Reinforced Soil Integrated Bridge System (GRS-IBS) uses alternating layers of closely spaced : geosynthetic reinforcement and well-compacted granular fill to support the bridge superstructure and form an integrated roadway : approach...

ATLAS event display: Virtual Point-1 visualization software

NASA Astrophysics Data System (ADS)

Seeley, Kaelyn; Dimond, David; Bianchi, R. M.; Boudreau, Joseph; Hong, Tae Min; Atlas Collaboration

2017-01-01

Virtual Point-1 (VP1) is an event display visualization software for the ATLAS Experiment. VP1 is a software framework that makes use of ATHENA, the ATLAS software infrastructure, to access the complete detector geometry. This information is used to draw graphics representing the components of the detector at any scale. Two new features are added to VP1. The first is a traditional ``lego'' plot, displaying the calorimeter energy deposits in eta-phi space. The second is another lego plot focusing on the forward endcap region, displaying the energy deposits in r-phi space. Currently, these new additions display the energy deposits based on the granularity of the middle layer of the liquid-Argon electromagnetic calorimeter. Since VP1 accesses the complete detector geometry and all experimental data, future developments are outlined for a more detailed display involving multiple layers of the calorimeter along with their distinct granularities.

Validation of GEANT4 Monte Carlo models with a highly granular scintillator-steel hadron calorimeter

NASA Astrophysics Data System (ADS)

Adloff, C.; Blaha, J.; Blaising, J.-J.; Drancourt, C.; Espargilière, A.; Gaglione, R.; Geffroy, N.; Karyotakis, Y.; Prast, J.; Vouters, G.; Francis, K.; Repond, J.; Schlereth, J.; Smith, J.; Xia, L.; Baldolemar, E.; Li, J.; Park, S. T.; Sosebee, M.; White, A. P.; Yu, J.; Buanes, T.; Eigen, G.; Mikami, Y.; Watson, N. K.; Mavromanolakis, G.; Thomson, M. A.; Ward, D. R.; Yan, W.; Benchekroun, D.; Hoummada, A.; Khoulaki, Y.; Apostolakis, J.; Dotti, A.; Folger, G.; Ivantchenko, V.; Uzhinskiy, V.; Benyamna, M.; Cârloganu, C.; Fehr, F.; Gay, P.; Manen, S.; Royer, L.; Blazey, G. C.; Dyshkant, A.; Lima, J. G. R.; Zutshi, V.; Hostachy, J.-Y.; Morin, L.; Cornett, U.; David, D.; Falley, G.; Gadow, K.; Göttlicher, P.; Günter, C.; Hermberg, B.; Karstensen, S.; Krivan, F.; Lucaci-Timoce, A.-I.; Lu, S.; Lutz, B.; Morozov, S.; Morgunov, V.; Reinecke, M.; Sefkow, F.; Smirnov, P.; Terwort, M.; Vargas-Trevino, A.; Feege, N.; Garutti, E.; Marchesini, I.; Ramilli, M.; Eckert, P.; Harion, T.; Kaplan, A.; Schultz-Coulon, H.-Ch; Shen, W.; Stamen, R.; Bilki, B.; Norbeck, E.; Onel, Y.; Wilson, G. W.; Kawagoe, K.; Dauncey, P. D.; Magnan, A.-M.; Bartsch, V.; Wing, M.; Salvatore, F.; Calvo Alamillo, E.; Fouz, M.-C.; Puerta-Pelayo, J.; Bobchenko, B.; Chadeeva, M.; Danilov, M.; Epifantsev, A.; Markin, O.; Mizuk, R.; Novikov, E.; Popov, V.; Rusinov, V.; Tarkovsky, E.; Kirikova, N.; Kozlov, V.; Smirnov, P.; Soloviev, Y.; Buzhan, P.; Ilyin, A.; Kantserov, V.; Kaplin, V.; Karakash, A.; Popova, E.; Tikhomirov, V.; Kiesling, C.; Seidel, K.; Simon, F.; Soldner, C.; Szalay, M.; Tesar, M.; Weuste, L.; Amjad, M. S.; Bonis, J.; Callier, S.; Conforti di Lorenzo, S.; Cornebise, P.; Doublet, Ph; Dulucq, F.; Fleury, J.; Frisson, T.; van der Kolk, N.; Li, H.; Martin-Chassard, G.; Richard, F.; de la Taille, Ch; Pöschl, R.; Raux, L.; Rouëné, J.; Seguin-Moreau, N.; Anduze, M.; Boudry, V.; Brient, J.-C.; Jeans, D.; Mora de Freitas, P.; Musat, G.; Reinhard, M.; Ruan, M.; Videau, H.; Bulanek, B.; Zacek, J.; Cvach, J.; Gallus, P.; Havranek, M.; Janata, M.; Kvasnicka, J.; Lednicky, D.; Marcisovsky, M.; Polak, I.; Popule, J.; Tomasek, L.; Tomasek, M.; Ruzicka, P.; Sicho, P.; Smolik, J.; Vrba, V.; Zalesak, J.; Belhorma, B.; Ghazlane, H.; Takeshita, T.; Uozumi, S.; Götze, M.; Hartbrich, O.; Sauer, J.; Weber, S.; Zeitnitz, C.

2013-07-01

Calorimeters with a high granularity are a fundamental requirement of the Particle Flow paradigm. This paper focuses on the prototype of a hadron calorimeter with analog readout, consisting of thirty-eight scintillator layers alternating with steel absorber planes. The scintillator plates are finely segmented into tiles individually read out via Silicon Photomultipliers. The presented results are based on data collected with pion beams in the energy range from 8 GeV to 100 GeV. The fine segmentation of the sensitive layers and the high sampling frequency allow for an excellent reconstruction of the spatial development of hadronic showers. A comparison between data and Monte Carlo simulations is presented, concerning both the longitudinal and lateral development of hadronic showers and the global response of the calorimeter. The performance of several GEANT4 physics lists with respect to these observables is evaluated.

Changes in CB1 and CB2 receptors in the post-mortem cerebellum of humans affected by spinocerebellar ataxias

PubMed Central

Rodríguez-Cueto, Carmen; Benito, Cristina; Fernández-Ruiz, Javier; Romero, Julián; Hernández-Gálvez, Mariluz; Gómez-Ruiz, María

2014-01-01

Background and PurposeSpinocerebellar ataxias (SCAs) are a family of chronic progressive neurodegenerative diseases, clinically and genetically heterogeneous, characterized by loss of balance and motor coordination due to degeneration of the cerebellum and its afferent and efferent connections. Unlike other motor disorders, the possible role of changes in the endocannabinoid system in the pathogenesis of SCAs has not been investigated. Experimental ApproachThe status of cannabinoid receptor type 1 (CB1) and cannabinoid receptor type 2 (CB2) receptors in the post-mortem cerebellum of SCA patients and controls was investigated using immunohistochemical procedures. Key ResultsImmunoreactivity for the CB1 receptor, and also for the CB2 receptor, was found in the granular layer, Purkinje cells, neurons of the dentate nucleus and areas of white matter in the cerebellum of SCA patients at levels notably higher than controls. Double-labelling procedures demonstrated co-localization of CB1 and, in particular, CB2 receptors with calbindin, supporting the presence of these receptors in Purkinje neurons. Both receptors also co-localized with Iba-1 and glial fibrillary acidic protein in the granular layer and white matter areas, indicating that they are present in microglia and astrocytes respectively. Conclusions and ImplicationsOur results demonstrate that CB1 and CB2 receptor levels are significantly altered in the cerebellum of SCA patients. Their identification in Purkinje neurons, which are the main cells affected in SCAs, as well as the changes they experienced, suggest that alterations in endocannabinoid receptors may be related to the pathogenesis of SCAs. Therefore, the endocannabinoid system could provide potential therapeutic targets for the treatment of SCAs and its progression. Linked ArticlesThis article is part of a themed section on Cannabinoids 2013. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2014.171.issue-6 PMID:23808969

Effect of granular activated carbon addition on the effluent properties and fouling potentials of membrane-coupled expanded granular sludge bed process.

PubMed

Ding, An; Liang, Heng; Qu, Fangshu; Bai, Langming; Li, Guibai; Ngo, Huu Hao; Guo, Wenshan

2014-11-01

To mitigate membrane fouling of membrane-coupled anaerobic process, granular activated carbon (GAC: 50 g/L) was added into an expanded granular sludge bed (EGSB). A short-term ultrafiltration test was investigated for analyzing membrane fouling potential and underlying fouling mechanisms. The results showed that adding GAC into the EGSB not only improved the COD removal efficiency, but also alleviated membrane fouling efficiently because GAC could help to reduce soluble microbial products, polysaccharides and proteins by 26.8%, 27.8% and 24.7%, respectively, compared with the control system. Furthermore, excitation emission matrix (EEM) fluorescence spectroscopy analysis revealed that GAC addition mainly reduced tryptophan protein-like, aromatic protein-like and fulvic-like substances. In addition, the resistance distribution analysis demonstrated that adding GAC primarily decreased the cake layer resistance by 53.5%. The classic filtration mode analysis showed that cake filtration was the major fouling mechanism for membrane-coupled EGSB process regardless of the GAC addition. Copyright © 2014 Elsevier Ltd. All rights reserved.

Junction formation of Cu3BiS3 investigated by Kelvin probe force microscopy and surface photovoltage measurements

PubMed Central

Mesa, Fredy; Chamorro, William; Vallejo, William; Baier, Robert; Dittrich, Thomas; Grimm, Alexander; Lux-Steiner, Martha C

2012-01-01

Summary Recently, the compound semiconductor Cu3BiS3 has been demonstrated to have a band gap of ~1.4 eV, well suited for photovoltaic energy harvesting. The preparation of polycrystalline thin films was successfully realized and now the junction formation to the n-type window needs to be developed. We present an investigation of the Cu3BiS3 absorber layer and the junction formation with CdS, ZnS and In2S3 buffer layers. Kelvin probe force microscopy shows the granular structure of the buffer layers with small grains of 20–100 nm, and a considerably smaller work-function distribution for In2S3 compared to that of CdS and ZnS. For In2S3 and CdS buffer layers the KPFM experiments indicate negatively charged Cu3BiS3 grain boundaries resulting from the deposition of the buffer layer. Macroscopic measurements of the surface photovoltage at variable excitation wavelength indicate the influence of defect states below the band gap on charge separation and a surface-defect passivation by the In2S3 buffer layer. Our findings indicate that Cu3BiS3 may become an interesting absorber material for thin-film solar cells; however, for photovoltaic application the band bending at the charge-selective contact has to be increased. PMID:22497001

Junction formation of Cu(3)BiS(3) investigated by Kelvin probe force microscopy and surface photovoltage measurements.

PubMed

Mesa, Fredy; Chamorro, William; Vallejo, William; Baier, Robert; Dittrich, Thomas; Grimm, Alexander; Lux-Steiner, Martha C; Sadewasser, Sascha

2012-01-01

Recently, the compound semiconductor Cu(3)BiS(3) has been demonstrated to have a band gap of ~1.4 eV, well suited for photovoltaic energy harvesting. The preparation of polycrystalline thin films was successfully realized and now the junction formation to the n-type window needs to be developed. We present an investigation of the Cu(3)BiS(3) absorber layer and the junction formation with CdS, ZnS and In(2)S(3) buffer layers. Kelvin probe force microscopy shows the granular structure of the buffer layers with small grains of 20-100 nm, and a considerably smaller work-function distribution for In(2)S(3) compared to that of CdS and ZnS. For In(2)S(3) and CdS buffer layers the KPFM experiments indicate negatively charged Cu(3)BiS(3) grain boundaries resulting from the deposition of the buffer layer. Macroscopic measurements of the surface photovoltage at variable excitation wavelength indicate the influence of defect states below the band gap on charge separation and a surface-defect passivation by the In(2)S(3) buffer layer. Our findings indicate that Cu(3)BiS(3) may become an interesting absorber material for thin-film solar cells; however, for photovoltaic application the band bending at the charge-selective contact has to be increased.

The src-family protein-tyrosine kinase p59hck is located on the secretory granules in human neutrophils and translocates towards the phagosome during cell activation.

PubMed Central

Möhn, H; Le Cabec, V; Fischer, S; Maridonneau-Parini, I

1995-01-01

The src-family protein-tyrosine kinase p59hck is mainly expressed in neutrophils; however, its functional role in these cells is unknown. Several other src-family members are localized on secretory vesicles and have been proposed to regulate intracellular traffic. We have established here the subcellular localization of p59hck in human neutrophils. Immunoblotting of subcellular fractions showed that approx. 60% of the p59hck per cell is localized on the secretory granules; the other 40% is distributed equally between non-granular membranes and the cytosol. Immunofluorescence of neutrophils and HL60 cells suggests that the p59hck-positive granules are azurophil granules. Granular p59hck is highly susceptible to degradation by an azurophil-granule proteinase. Different forms of p59hck occur in the three subcellular compartments: a 61 kDa form is mainly found in the granules, a 59 kDa form is predominant in the non-granular membranes, whereas cytosolic p59hck migrates as a doublet at 63 kDa. During the process of phagocytosis-linked degranulation, induced by serum-opsonized zymosan in neutrophils or HL60 cells, granular p59hck translocates towards the phagosome. The subcellular localization of p59hck suggests that the enzyme could be involved in the regulation of the degranulation process. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 PMID:7626033

Immunohistochemical localization of cannabinoid receptor 1 (CB1) in the submandibular gland of mice under normal conditions and when stimulated by isoproterenol or carbachol.

PubMed

Thoungseabyoun, Wipawee; Tachow, Apussara; Pakkarato, Sawetree; Rawangwong, Atsara; Krongyut, Suthankamon; Sakaew, Waraporn; Kondo, Hisatake; Hipkaeo, Wiphawi

2017-09-01

We wished to investigate the subcellular localization of CB1, a receptor for the endocannabinoids in mouse submandibular glands (SMGs) under normal conditions and when stimulated by adrenergic or cholinergic agonists. SMGs of both male and female adult mice were utilized for immunoblotting and immuno-light and -electron microscopic analyses. Isoproterenol and carbachol were used as adrenergic and cholinergic stimulants, respectively. SMGs were examined at 15, 30, 60 and 120min after intraperitoneal injection of these agents. Selective localization of intense immunoreactivity for CB1 in the granular convoluted ductal cells was confirmed by immunoblotting and the antigen absorption test. In SMGs of control male mice, CB1-immunoreactivity was evident on the basolateral plasma membranes, including the basal infoldings, but was absent on the apical membranes in the ductal cells. Localization and intensity of CB1-immunoreactivity were essentially the same in SMGs of female mice. The immunoreactivity was transiently localized in the apical plasmalemma of some acinar and granular ductal cells of male SMGs shortly after stimulation by isoproterenol, but not by carbachol. The present finding suggests that CB1 functions primarily in the basolateral membranes of the granular convoluted ductal cells of SMGs under normal conditions, and that the CB1 can function additionally in the apical membrane of acinar and granular ductal cells for modulation of the saliva secretory condition via adrenoceptors. Copyright © 2017 Elsevier Ltd. All rights reserved.

Removal of As(V) and Sb(V) in aqueous solution by Mg/Al-layered double hydroxide-incorporated polyethersulfone polymer beads (PES-LDH).

PubMed

Lee, Sang-Ho; Choi, Heechul; Kim, Kyoung-Woong

2018-03-13

To develop a novel granular adsorbent to remove arsenic and antimony from water, calcined Mg/Al-layered double-hydroxide (CLDH)-incorporated polyethersulfone (PES) granular adsorbents (PES-LDH) were prepared using a core-shell method having 25% PES in an N,N-dimethylformamide solution. The PES-LDH displayed a spherical hollow shape having a rough surface and the average particle size of 1-2 mm. On the PES-LDH surface, nanosized CLDH (100-150 nm) was successfully immobilized by consolidation between PES and CLDH. The adsorption of Sb(V) by PES-LDH was found to be more favorable than for As(V), with the maximum adsorption capacity of As(V) and Sb(V) being 7.44 and 22.8 mg/g, respectively. The regeneration results indicated that a 0.5 M NaOH and 5 M NaCl mixed solution achieved an 80% regeneration efficiency in As(V) adsorption and desorption. However, the regeneration efficiency of Sb(V) gradually decreased due to its strong binding affinity, even though the PES-LDH showed much higher Sb(V) adsorption efficiency than As(V). This study suggested that PES-LDH could be a promising granular adsorbent for the remediation of As(V) and Sb(V) contained in wastewater.

Effects of Noise and Vibration on the Solid to Liquid Fluidization Transition in Small Dense Granular Systems Under Shear

NASA Astrophysics Data System (ADS)

Melhus, Martin Frederic

2011-07-01

Granular materials exhibit bulk properties that are distinct from conventional solids, liq- uids, and gases, due to the dissipative nature of the inter-granular forces. Understanding the fundamentals of granular materials draws upon and gives insight into many fields at the current frontiers of physics, such as plasticity of solids, fracture and friction, com- plex systems such as colloids, foams and suspensions, and a variety of biological systems. Particulate flows are widespread in geophysics, and are also essential to many industries. Despite the importance of these phenomena, we lack a theoretical model that explains most behaviors of granular materials. Since granular assemblies are highly dissipative, they are often far from mechanical equilibrium, making most classical analyses inappli- cable. A theory for dilute granular systems exists, but for dense granular systems (by far the majority of granular systems in the real world) no comparable theory is accepted. We approach this problem by examining the fluidization, or transition from solid to liquid, in dense granular systems. In this study, the separate effects of random noise and vibration on the static to flowing transition of a dense granular assembly under planar shear is studied numerically using soft contact particle dynamics simulations in two dimensions. We focus on small systems in a thin planar Couette cell, examining the bistable region while increasing shear, with varying amounts of random noise or vibration, and determine the statistics of the shear required for the onset of flow. We find that the applied power is the key parameter in determining the magnitude of the effects of the noise or vibration, with vibration frequency also having an influence. Similarities and differences between noise and vibration are determined, and the results compare favorably with a two phase model for dense granular flow.

Shear localization and effective wall friction in a wall bounded granular flow

NASA Astrophysics Data System (ADS)

Artoni, Riccardo; Richard, Patrick

2017-06-01

In this work, granular flow rheology is investigated by means of discrete numerical simulations of a torsional, cylindrical shear cell. Firstly, we focus on azimuthal velocity profiles and study the effect of (i) the confining pressure, (ii) the particle-wall friction coefficient, (iii) the rotating velocity of the bottom wall and (iv) the cell diameter. For small cell diameters, azimuthal velocity profiles are nearly auto-similar, i.e. they are almost linear with the radial coordinate. Different strain localization regimes are observed : shear can be localized at the bottom, at the top of the shear cell, or it can be even quite distributed. This behavior originates from the competition between dissipation at the sidewalls and dissipation in the bulk of the system. Then we study the effective friction at the cylindrical wall, and point out the strong link between wall friction, slip and fluctuations of forces and velocities. Even if the system is globally below the sliding threshold, force fluctuations trigger slip events, leading to a nonzero wall slip velocity and an effective wall friction coefficient different from the particle-wall one. A scaling law was found linking slip velocity, granular temperature in the main flow direction and effective friction. Our results suggest that fluctuations are an important ingredient for theories aiming to capture the interface rheology of granular materials.

A robot conditioned reflex system modeled after the cerebellum.

NASA Technical Reports Server (NTRS)

Albus, J. S.

1972-01-01

Reduction of a theory of cerebellar function to computer software for the control of a mechanical manipulator. This reduction is achieved by considering the cerebellum, along with the higher-level brain centers which control it, as a type of finite-state machine with input entering the cerebellum via mossy fibers from the periphery and output from the cerebellum occurring via Purkinje cells. It is hypothesized that the cerebellum learns by an error-correction system similar to Perceptron training algorithms. An electromechanical model of the cerebellum is then developed for the control of a mechanical arm. The problem of modeling the granular layer which selects the set of parallel fibers which are active at any instant of time is considered, and a relevance matrix is constructed to model the relative degree of influence which mossy fibers from the various joints have on the sets of granule cells unique to each joint.

The increase in the number of astrocytes in the total cerebral ischemia model in rats

NASA Astrophysics Data System (ADS)

Kudabayeva, M.; Kisel, A.; Chernysheva, G.; Smol'yakova, V.; Plotnikov, M.; Khodanovich, M.

2017-08-01

Astrocytes are the most abundant cell class in the CNS. Astrocytic therapies have a huge potential for neuronal repair after stroke. The majority of brain stroke studies address the damage to neurons. Modern studies turn to the usage of morphological and functional changes in astroglial cells after stroke in regenerative medicine. Our study is focused on the changes in the number of astrocytes in the hippocampus (where new glia cells divide) after brain ischemia. Ischemia was modeled by occlusion of tr. brachiocephalicus, a. subclavia sin., a. carotis communis sin. Astrocytes were determined using immunohistochemical labeling with anti GFAP antibody. We found out that the number of astrocytes increased on the 10th and 30th days after stroke in the CA1, CA2 fields, the granular layer of dentate gyrus (GrDG) and hilus. The morphology of astrocytes became reactive in these regions. Therefore, our results revealed long-term reactive astrogliosis in the hippocampus region after total ischemia in rats.

Three-dimensional cytomorphology in fine needle aspiration biopsy of medullary thyroid carcinoma.

PubMed

Chang, T C; Lai, S M; Wen, C Y; Hsiao, Y L; Huang, S H

2001-01-01

To elucidate three-dimensional (3-D) cytomorphology in fine needle aspiration biopsy (FNAB) of medullary thyroid carcinoma (MTC). ENAB was performed on tumors from five patients with MTC. The aspirate was stained and observed under a light microscope (LM). The aspirate was also fixed, dehydrated, critical point dried, spattered with gold ions and observed with a scanning electron microscope (SEM). For transmission electron microscopy (TEM), the specimen was fixed, dehydrated, embedded in an Epon mixture, cut with an ultramicrotome, mounted on copper grids, electron doubly stained with uranium acetate and lead citrate, and observed with TEM. Findings under SEM were correlated with those under LM and TEM. Under SEM, 3-D cytomorphology of MTC displayed a disorganized cellular arrangement with indistinct cell borders in three cases. The cell surface was uneven and had granular protrusions that corresponded to secretory granules observed under TEM. In one case with multiple endocrine neoplasia type IIB, there were abundant granules on the cell surface. In one case of sporadic MTC with multinucleated tumor giant cells and small cells, granular protrusions also were noted on the cell surface. Granular protrusion was a characteristic finding in FNAB of MTC tinder SEM and might be helpful in the differential diagnosis.

Design and Prototyping of a High Granularity Scintillator Calorimeter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zutshi, Vishnu

A novel approach for constructing fine-granularity scintillator calorimeters, based on the concept of an Integrated Readout Layer (IRL) was developed. The IRL consists of a printed circuit board inside the detector which supports the directly-coupled scintillator tiles, connects to the surface-mount SiPMs and carries the necessary front-end electronics and signal/bias traces. Prototype IRLs using this concept were designed, prototyped and successfully exposed to test beams. Concepts and implementations of an IRL carried out with funds associated with this contract promise to result in the next generation of scintillator calorimeters.

ELECTROCHEMICAL DEGRADATION OF TRICHLOROETHYLENE USING GRANULAR-GRAPHITE ELECTRODES: IDENTIFICATION AND QUALIFICATION OF DECHLORINATION PRODUCTS

EPA Science Inventory

TCE was successfully dechlorinated in aqueous solution using granular graphite as the cathode in a mixed electrochemical reactor. In experiments with an initial TCE concentration of less than 100 mg/l, TCE was reduced approximately by 75% in the reactor under an applied cell volt...

Differential settlement of a geosynthetic reinforced soil abutment : full-scale investigation : summary report.

DOT National Transportation Integrated Search

2015-05-01

The Geosynthetic Reinforced Soil Integrated Bridge System (GRS-IBS) uses alternating layers of closely spaced : geosynthetic reinforcement and well-compacted granular fill to support the bridge superstructure and form an integrated roadway : approach...

Long‐Term Monitoring of a Geosynthetic Reinforced Soil Integrated Bridge System (GRS‐IBS)

DOT National Transportation Integrated Search

2017-11-01

The geosynthetic reinforced soil integrated bridge system (GRS-IBS) is an innovative alternative to conventional bridge technology that utilizes closely spaced layers of geosynthetic reinforcement and compacted granular fill material to provide direc...

Backcalculation of unbound granular layer moduli.

DOT National Transportation Integrated Search

2011-03-01

The state of Michigan is geographically located within the wet-freeze zone identified by the : American Association of States and Highway Transportation Officials (AASHTO). The frost : depth in the State ranges from 2.5 feet near the Ohio and Indiana...

Orbital meningioma with a granular cell component in a dog, with extracranial metastasis.

PubMed

Pérez, V; Vidal, E; González, N; Benavides, J; Ferreras, M C; Villagrasa, M; Pumarola, M

2005-01-01

A meningioma with a significant component of granular cells is described in the left ocular orbit of a 5-year-old male Golden retriever dog that presented with exophthalmos. The neoplastic mass surrounded the optic nerve. Microscopically, the tumour was characterized by nests of large, round to polygonal cells, variable in size, with eccentric nuclei and abundant eosinophilic cytoplasm, containing PAS-positive granules. In focal areas, cells were smaller and occasionally formed whorl-like structures. Immunohistochemical analysis revealed that neoplastic cells reacted positively for vimentin and, with less intensity, for neuron specific enolase and S-100, whereas they were negative for glial fibrillary acidic protein and cytokeratins. Metastatic growths, formed by similar cells, were seen in the lung and heart.

Neuronal and Astrocytic Monoacylglycerol Lipase Limit the Spread of Endocannabinoid Signaling in the Cerebellum.

PubMed

Chen, Yao; Liu, Xiaojie; Vickstrom, Casey R; Liu, Michelle J; Zhao, Li; Viader, Andreu; Cravatt, Benjamin F; Liu, Qing-Song

2016-01-01

Endocannabinoids are diffusible lipophilic molecules that may spread to neighboring synapses. Monoacylglycerol lipase (MAGL) is the principal enzyme that degrades the endocannabinoid 2-arachidonoylglycerol (2-AG). Using knock-out mice in which MAGL is deleted globally or selectively in neurons and astrocytes, we investigated the extent to which neuronal and astrocytic MAGL limit the spread of 2-AG-mediated retrograde synaptic depression in cerebellar slices. A brief tetanic stimulation of parallel fibers in the molecular layer induced synaptically evoked suppression of excitation (SSE) in Purkinje cells, and both neuronal and astrocytic MAGL contribute to the termination of this form of endocannabinoid-mediated synaptic depression. The spread of SSE among Purkinje cells occurred only after global knock-out of MAGL or pharmacological blockade of either MAGL or glutamate uptake, but no spread was detected following neuron- or astrocyte-specific deletion of MAGL. The spread of endocannabinoid signaling was also influenced by the spatial pattern of synaptic stimulation, because it did not occur at spatially dispersed parallel fiber synapses induced by stimulating the granular layer. The tetanic stimulation of parallel fibers did not induce endocannabinoid-mediated synaptic suppression in Golgi cells even after disruption of MAGL and glutamate uptake, suggesting that heightened release of 2-AG by Purkinje cells does not spread the retrograde signal to parallel fibers that innervate Golgi cells. These results suggest that both neuronal and astrocytic MAGL limit the spatial diffusion of 2-AG and confer synapse-specificity of endocannabinoid signaling.

Metagenomic and metaproteomic analyses of Accumulibacter phosphatis-enriched floccular and granular biofilm.

PubMed

Barr, Jeremy J; Dutilh, Bas E; Skennerton, Connor T; Fukushima, Toshikazu; Hastie, Marcus L; Gorman, Jeffrey J; Tyson, Gene W; Bond, Philip L

2016-01-01

Biofilms are ubiquitous in nature, forming diverse adherent microbial communities that perform a plethora of functions. Here we operated two laboratory-scale sequencing batch reactors enriched with Candidatus Accumulibacter phosphatis (Accumulibacter) performing enhanced biological phosphorus removal. Reactors formed two distinct biofilms, one floccular biofilm, consisting of small, loose, microbial aggregates, and one granular biofilm, forming larger, dense, spherical aggregates. Using metagenomic and metaproteomic methods, we investigated the proteomic differences between these two biofilm communities, identifying a total of 2022 unique proteins. To understand biofilm differences, we compared protein abundances that were statistically enriched in both biofilm states. Floccular biofilms were enriched with pathogenic secretion systems suggesting a highly competitive microbial community. Comparatively, granular biofilms revealed a high-stress environment with evidence of nutrient starvation, phage predation pressure, and increased extracellular polymeric substance and cell lysis. Granular biofilms were enriched in outer membrane transport proteins to scavenge the extracellular milieu for amino acids and other metabolites, likely released through cell lysis, to supplement metabolic pathways. This study provides the first detailed proteomic comparison between Accumulibacter-enriched floccular and granular biofilm communities, proposes a conceptual model for the granule biofilm, and offers novel insights into granule biofilm formation and stability. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

Evolution of a primary pulse in the granular dimers mounted on a linear elastic foundation: An analytical and numerical study.

PubMed

Ahsan, Zaid; Jayaprakash, K R

2016-10-01

In this exposition we consider the wave dynamics of a one-dimensional periodic granular dimer (diatomic) chain mounted on a damped and an undamped linear elastic foundation (otherwise called the on-site potential). It is very well known that periodic granular dimers support solitary wave propagation (similar to that in the homogeneous granular chains) for a specific discrete set of mass ratios. In this work we present the analytical investigation of the evolution of solitary waves and primary pulses in granular dimers when they are mounted on on-site potential with and without velocity proportional foundation damping. We invoke a methodology based on the multiple time-scale asymptotic analysis and partition the dynamics of the perturbed dimer chain into slow and fast components. The dynamics of the dimer chain in the limit of large mass mismatch (auxiliary chain) mounted on on-site potential and foundation damping is used as the basis for the analysis. A systematic analytical procedure is then developed for the slowly varying response of the beads and in estimating primary pulse amplitude evolution resulting in a nonlinear map relating the relative displacement amplitudes of two adjacent beads. The methodology is applicable for arbitrary mass ratios between the beads. We present several examples to demonstrate the efficacy of the proposed method. It is observed that the amplitude evolution predicted by the described methodology is in good agreement with the numerical simulation of the original system. This work forms a basis for further application of the considered methodology to weakly coupled granular dimers which finds practical relevance in designing shock mitigating granular layers.

Contact force structure and force chains in 3D sheared granular systems

NASA Astrophysics Data System (ADS)

Mair, Karen; Jettestuen, Espen; Abe, Steffen

2010-05-01

Faults often exhibit accumulations of granular debris, ground up to create a layer of rock flour or fault gouge separating the rigid fault walls. Numerical simulations and laboratory experiments of sheared granular materials, suggest that applied loads are preferentially transmitted across such systems by transient force networks that carry enhanced forces. The characterisation of such features is important since their nature and persistence almost certainly influence the macroscopic mechanical stability of these systems and potentially that of natural faults. 3D numerical simulations of granular shear are a valuable investigation tool since they allow us to track individual particle motions, contact forces and their evolution during applied shear, that are difficult to view directly in laboratory experiments or natural fault zones. In characterising contact force distributions, it is important to use global structure measures that allow meaningful comparisons of granular systems having e.g. different grain size distributions, as may be expected at different stages of a fault's evolution. We therefore use a series of simple measures to characterise the structure, such as distributions and correlations of contact forces that can be mapped onto a force network percolation problem as recently proposed by Ostojic and coworkers for 2D granular systems. This allows the use of measures from percolation theory to both define and characterise the force networks. We demonstrate the application of this method to 3D simulations of a sheared granular material. Importantly, we then compare our measure of the contact force structure with macroscopic frictional behaviour measured at the boundaries of our model to determine the influence of the force networks on macroscopic mechanical stability.

Malignant granular cell tumors: the role of electron microscopy in the definitive diagnosis of an extremely aggressive soft tissue neoplasm.

PubMed

Knowles, Kurt J; Al-Delfi, Firas; Abdulsattar, Jehan; Lacour, Robin; Black, Destin; Chaudhery, Shabnum; Turbat-Herrera, Elba A

2018-01-01

Granular cell tumors (GCTs) are rare soft tissue neoplasms which may be multicentric. The vast majority are benign, however approximately 100 malignant GCTs have been reported, with only 8 originating in the vulva. Malignant GCTs are very aggressive with very poor survival rates. As the diagnosis of malignant GCT carries an extremely poor prognosis, the utilization of EM ensures that the most accurate diagnosis possible can be rendered.

Corals Use Similar Immune Cells and Wound-Healing Processes as Those of Higher Organisms

PubMed Central

Palmer, Caroline V.; Traylor-Knowles, Nikki G.; Willis, Bette L.; Bythell, John C.

2011-01-01

Sessile animals, like corals, frequently suffer physical injury from a variety of sources, thus wound-healing mechanisms that restore tissue integrity and prevent infection are vitally important for defence. Despite the ecological importance of reef-building corals, little is known about the cells and processes involved in wound healing in this group or in phylogenetically basal metazoans in general. A histological investigation into wound healing of the scleractinian coral Porites cylindrica at 0 h, 6 h, 24 h and 48 h after injury revealed differences in cellular components between injured and healthy tissues. Cell counts of the obligate endosymbiont, Symbiodinium, and melanin volume fraction analysis revealed rapid declines in both Symbiodinium abundance and tissue cross-sectional area occupied by melanin-containing granular cells after injury. Four phases of wound healing were identified, which are similar to phases described for both vertebrates and invertebrates. The four phases included (i) plug formation via the degranulation of melanin-containing granular cells; (ii) immune cell infiltration (inflammation); (iii) granular tissue formation (proliferation); and (iv) maturation. This study provides detailed documentation of the processes involved in scleractinian wound healing for the first time and further elucidates the roles of previously-described immune cells, such as fibroblasts. These results demonstrate the conservation of wound healing processes from anthozoans to humans. PMID:21887359

Characterising fabric, force distributions and porosity evolution in sheared granular media

NASA Astrophysics Data System (ADS)

Mair, Karen; Abe, Steffen; Jettestuen, Espen

2014-05-01

Active faults, landslides, subglacial tills and poorly or unconsolidated sands essentially contain accumulations of granular debris that evolve under load. Both the macroscopic motions and the bulk fluid flow characteristics that result are determined by the particular grain scale processes operating in this deformed or transformed granular material. A relevant question is how the local behavior at the individual granular contacts actually sums up, and in particular how the load bearing skeleton (an important expression of connected load) and spatial distribution of pore space (and hence fluid pathways) are linked. Here we investigate the spatial distribution of porosity with granular rearrangements (specifically contact force network characteristics) produced in 3D discrete element models of granular layers under shear. We use percolation measures to identify, characterize, compare and track the evolution of strongly connected contact force networks. We show that specific topological measures used in describing the networks, such as number of contacts and coordination number, are sensitive to grain size distribution of the material as well as loading conditions. In addition we probe the 3D spatial distribution of porosity as a function of increasing strain. Two cases will be considered. The first, a non-fracture regime where configurational changes occur during shear but grain size distribution remains constant. This would be expected for a soil or granular material under relatively low normal loading. Secondly we consider a fragmentation regime where the grain size distributions of the granular material evolve with accumulated strain. This mirrors the scenario for faults or basal shear zones of slides under higher normal stress where comminution is typically a mark of increasing maturity and plays a major role in the poro-perm evolution of the system. We will present the correlated and anti-correlated features appearing in our simulations as well as discussing the triggers and relative persistence of fluid pathway creation versus destruction mechanisms. We will also demonstrate how the individual grain interactions are manifested in the macroscopic sliding behavior we observe.

Nonlocal rheological properties of granular flows near a jamming limit.

PubMed

Aranson, Igor S; Tsimring, Lev S; Malloggi, Florent; Clément, Eric

2008-09-01

We study the rheology of sheared granular flows close to a jamming transition. We use the approach of partially fluidized theory (PFT) with a full set of equations extending the thin layer approximation derived previously for the description of the granular avalanches phenomenology. This theory provides a picture compatible with a local rheology at large shear rates [G. D. R. Midi, Eur. Phys. J. E 14, 341 (2004)] and it works in the vicinity of the jamming transition, where a description in terms of a simple local rheology comes short. We investigate two situations displaying important deviations from local rheology. The first one is based on a set of numerical simulations of sheared soft two-dimensional circular grains. The next case describes previous experimental results obtained on avalanches of sandy material flowing down an incline. Both cases display, close to jamming, significant deviations from the now standard Pouliquen's flow rule [O. Pouliquen, Phys. Fluids 11, 542 (1999); 11, 1956 (1999)]. This discrepancy is the hallmark of a strongly nonlocal rheology and in both cases, we relate the empirical results and the outcomes of PFT. The numerical simulations show a characteristic constitutive structure for the fluid part of the stress involving the confining pressure and the material stiffness that appear in the form of an additional dimensionless parameter. This constitutive relation is then used to describe the case of sandy flows. We show a quantitative agreement as far as the effective flow rules are concerned. A fundamental feature is identified in PFT as the existence of a jammed layer developing in the vicinity of the flow arrest that corroborates the experimental findings. Finally, we study the case of solitary erosive granular avalanches and relate the outcome with the PFT analysis.

Non-local rheological properties of granular flows near a jamming limit.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aranson, I. S.; Tsimring, L. S.; Malloggi, F.

2008-01-01

We study the rheology of sheared granular flows close to a jamming transition. We use the approach of partially fluidized theory (PFT) with a full set of equations extending the thin layer approximation derived previously for the description of the granular avalanches phenomenology. This theory provides a picture compatible with a local rheology at large shear rates [G. D. R. Midi, Eur. Phys. J. E 14, 341 (2004)] and it works in the vicinity of the jamming transition, where a description in terms of a simple local rheology comes short. We investigate two situations displaying important deviations from local rheology.more » The first one is based on a set of numerical simulations of sheared soft two-dimensional circular grains. The next case describes previous experimental results obtained on avalanches of sandy material flowing down an incline. Both cases display, close to jamming, significant deviations from the now standard Pouliquen's flow rule [O. Pouliquen, Phys. Fluids 11, 542 (1999); 11, 1956 (1999)]. This discrepancy is the hallmark of a strongly nonlocal rheology and in both cases, we relate the empirical results and the outcomes of PFT. The numerical simulations show a characteristic constitutive structure for the fluid part of the stress involving the confining pressure and the material stiffness that appear in the form of an additional dimensionless parameter. This constitutive relation is then used to describe the case of sandy flows. We show a quantitative agreement as far as the effective flow rules are concerned. A fundamental feature is identified in PFT as the existence of a jammed layer developing in the vicinity of the flow arrest that corroborates the experimental findings. Finally, we study the case of solitary erosive granular avalanches and relate the outcome with the PFT analysis.« less

Mechanics of Granular Materials (MGM) Test Cell

NASA Technical Reports Server (NTRS)

1998-01-01

A test cell for Mechanics of Granular Materials (MGM) experiment is shown approximately 20 and 60 minutes after the start of an experiment on STS-89. Sand and soil grains have faces that can cause friction as they roll and slide against each other, or even cause sticking and form small voids between grains. This complex behavior can cause soil to behave like a liquid under certain conditions such as earthquakes or when powders are handled in industrial processes. Mechanics of Granular Materials (MGM) experiments aboard the Space Shuttle use the microgravity of space to simulate this behavior under conditons that carnot be achieved in laboratory tests on Earth. MGM is shedding light on the behavior of fine-grain materials under low effective stresses. Applications include earthquake engineering, granular flow technologies (such as powder feed systems for pharmaceuticals and fertilizers), and terrestrial and planetary geology. Nine MGM specimens have flown on two Space Shuttle flights. Another three are scheduled to fly on STS-107. The principal investigator is Stein Sture of the University of Colorado at Boulder. Credit: NASA/Marshall Space Flight Center (MSFC)

Mechanics of Granular Materials Test Cell

NASA Technical Reports Server (NTRS)

1998-01-01

A test cell for Mechanics of Granular Materials (MGM) experiment is shown from all three sides by its video camera during STS-89. Sand and soil grains have faces that can cause friction as they roll and slide against each other, or even cause sticking and form small voids between grains. This complex behavior can cause soil to behave like a liquid under certain conditions such as earthquakes or when powders are handled in industrial processes. Mechanics of Granular Materials (MGM) experiments aboard the Space Shuttle use the microgravity of space to simulate this behavior under conditons that carnot be achieved in laboratory tests on Earth. MGM is shedding light on the behavior of fine-grain materials under low effective stresses. Applications include earthquake engineering, granular flow technologies (such as powder feed systems for pharmaceuticals and fertilizers), and terrestrial and planetary geology. Nine MGM specimens have flown on two Space Shuttle flights. Another three are scheduled to fly on STS-107. The principal investigator is Stein Sture of the University of Colorado at Boulder. Credit: NASA/Marshall Space Flight Center (MSFC)

Follicular hybrid cyst: a combination of bullous pilomatricoma and epidermoid cyst.

PubMed

Sanusi, Tutyana; Qu, Xiaoying; Li, Yanqiu; Zhang, Jing; Wang, Ming; Zhao, Yun; Yang, Zhen; An, Xiangjie; Qian, Yue; Wang, Chunsen; Chen, Hongxiang; Chen, Siyuan; Huang, Changzheng

2013-01-01

The follicular hybrid is composed of more than two components of pilosebaceous unit. There are several studies of hybrid cyst, combination of trichilemmal and epidermoid cyst was the most frequently reported. In this paper, we reported one case of hybrid cyst composed of bullous pilomatricoma and epidermoid cyst. A 14-year-old girl was complaint of a solitary flesh-colored to erythematous nodule with flaccid appearance sized 3.2 × 1.8 cm in diameter on her right upper back for one year. The histologic findings showed there were edema and proliferation of capillaries in the superficial dermis, a cyst in the middle to deep dermis. There were laminated keratins in the cystic space. The cyst wall was composed of two different components, one was composed of epithelial cells containing of granular layer, and another consisted of basophilic cells, transient cells and shadow cells. The cyst not related with Gardner's syndrome. Hybrid cyst such as trichilemmal cyst, epidermoid and pilomatricoma cysts maybe have same clinical features or mimicking each others, but we can distinguish them from histopathology evaluation.

Follicular hybrid cyst: a combination of bullous pilomatricoma and epidermoid cyst

PubMed Central

Sanusi, Tutyana; Qu, Xiaoying; Li, Yanqiu; Zhang, Jing; Wang, Ming; Zhao, Yun; Yang, Zhen; An, Xiangjie; Qian, Yue; Wang, Chunsen; Chen, Hongxiang; Chen, Siyuan; Huang, Changzheng

2013-01-01

The follicular hybrid is composed of more than two components of pilosebaceous unit. There are several studies of hybrid cyst, combination of trichilemmal and epidermoid cyst was the most frequently reported. In this paper, we reported one case of hybrid cyst composed of bullous pilomatricoma and epidermoid cyst. A 14-year-old girl was complaint of a solitary flesh-colored to erythematous nodule with flaccid appearance sized 3.2×1.8 cm in diameter on her right upper back for one year. The histologic findings showed there were edema and proliferation of capillaries in the superficial dermis, a cyst in the middle to deep dermis. There were laminated keratins in the cystic space. The cyst wall was composed of two different components, one was composed of epithelial cells containing of granular layer, and another consisted of basophilic cells, transient cells and shadow cells. The cyst not related with Gardner’s syndrome. Hybrid cyst such as trichilemmal cyst, epidermoid and pilomatricoma cysts maybe have same clinical features or mimicking each others, but we can distinguish them from histopathology evaluation. PMID:24294394

Malignant granular cell tumor of the breast; literature review.

PubMed

Gupta, Nalini; Sanchety, Naveen; Verma, Pragya Saran; Verma, Geeta

2015-01-01

Malignant granular cell tumor (MGCT) is rare tumors that comprise 1-2% of all granular cell tumors. They commonly arise on lower extremity, nuchal region, chest wall, gastrointestinal tract, head, and neck but very rarely in breast. We report a case of a MGCT of breast with review of literature. The patient had noticed a breast mass 4 years back which was operated, and wide local excision was done. The tumor was diagnosed as MGCT. The tumor fulfilled 3 of the 6 criteria of Fanburg-Smith et al. The patient received 8 cycles of chemotherapy thereafter with 4 cycles of antharacycline and 4 of taxanes. However, the tumor reoccurred 4 years after resection and grew rapidly. Contrast-enhanced computed tomography done showed a large lobulated breast mass with axillary lymph node metastasis. She underwent Modified Radical Mastectomy with axillary clearance. The histopathology this time also revealed similar malignant tumor. To the best of our knowledge, only 7 cases have been reported in indexed English literature occurring primarily in breast.

A Two-Phase Solid/Fluid Model for Dense Granular Flows Including Dilatancy Effects

NASA Astrophysics Data System (ADS)

Mangeney, Anne; Bouchut, Francois; Fernandez-Nieto, Enrique; Narbona-Reina, Gladys

2015-04-01

We propose a thin layer depth-averaged two-phase model to describe solid-fluid mixtures such as debris flows. It describes the velocity of the two phases, the compression/dilatation of the granular media and its interaction with the pore fluid pressure, that itself modifies the friction within the granular phase (Iverson et al., 2010). The model is derived from a 3D two-phase model proposed by Jackson (2000) based on the 4 equations of mass and momentum conservation within the two phases. This system has 5 unknowns: the solid and fluid velocities, the solid and fluid pressures and the solid volume fraction. As a result, an additional equation inside the mixture is necessary to close the system. Surprisingly, this issue is inadequately accounted for in the models that have been developed on the basis of Jackson's work (Bouchut et al., 2014). In particular, Pitman and Le replaced this closure simply by imposing an extra boundary condition at the surface of the flow. When making a shallow expansion, this condition can be considered as a closure condition. However, the corresponding model cannot account for a dissipative energy balance. We propose here an approach to correctly deal with the thermodynamics of Jackson's equations. We close the mixture equations by a weak compressibility relation involving a critical density, or equivalently a critical pressure. Moreover, we relax one boundary condition, making it possible for the fluid to escape the granular media when compression of the granular mass occurs. Furthermore, we introduce second order terms in the equations making it possible to describe the evolution of the pore fluid pressure in response to the compression/dilatation of the granular mass without prescribing an extra ad-hoc equation for the pore pressure. We prove that the energy balance associated with this Jackson closure is dissipative, as well as its thin layer associated model. We present several numerical tests for the 1D case that are compared to the results of the model proposed by Pitman and Le. Bouchut, Fernandez-Nieto, Mangeney, Narbona-Reina, 2014, ESAIM: Mathematical Modelling and Numerical Analysis, in press. Iverson et al., 2010, J. Geophys. Res. 115: F03005. Jackson, 2000, Cambridge Monographs on Mechanics. Pitman and Le, Phil.Trans. R. Soc. A 363, 1573-1601, 2005.

A Two-Phase Solid/Fluid Model for Dense Granular Flows Including Dilatancy Effects

NASA Astrophysics Data System (ADS)

Mangeney, A.; Bouchut, F.; Fernández-Nieto, E. D.; Narbona-Reina, G.; Kone, E. H.

2014-12-01

We propose a thin layer depth-averaged two-phase model to describe solid-fluid mixtures such as debris flows. It describes the velocity of the two phases, the compression/dilatation of the granular media and its interaction with the pore fluid pressure, that itself modifies the friction within the granular phase (Iverson et al., 2010). The model is derived from a 3D two-phase model proposed by Jackson (2000) based on the 4 equations of mass and momentum conservation within the two phases. This system has 5 unknowns: the solid and fluid velocities, the solid and fluid pressures and the solid volume fraction. As a result, an additional equation inside the mixture is necessary to close the system. Surprisingly, this issue is inadequately accounted for in the models that have been developed on the basis of Jackson's work (Bouchut et al., 2014). In particular, Pitman and Le replaced this closure simply by imposing an extra boundary condition at the surface of the flow. When making a shallow expansion, this condition can be considered as a closure condition. However, the corresponding model cannot account for a dissipative energy balance. We propose here an approach to correctly deal with the thermodynamics of Jackson's equations. We close the mixture equations by a weak compressibility relation involving a critical density, or equivalently a critical pressure. Moreover, we relax one boundary condition, making it possible for the fluid to escape the granular media when compression of the granular mass occurs. Furthermore, we introduce second order terms in the equations making it possible to describe the evolution of the pore fluid pressure in response to the compression/dilatation of the granular mass without prescribing an extra ad-hoc equation for the pore pressure. We prove that the energy balance associated with this Jackson closure is dissipative, as well as its thin layer associated model. We present several numerical tests for the 1D case that are compared to the results of the model proposed by Pitman and Le. Bouchut, Fernandez-Nieto, Mangeney, Narbona-Reina, 2014, ESAIM: Mathematical Modelling and Numerical Analysis, in press. Iverson, Logan, LaHusen, Berti, 2010, J. Geophys. Res. 115: F03005. Jackson, 2000, Cambridge Monographs on Mechanics. Pitman and Le, Phil.Trans. R. Soc. A 363, 1573-1601, 2005.

External front instabilities induced by a shocked particle ring.

PubMed

Rodriguez, V; Saurel, R; Jourdan, G; Houas, L

2014-10-01

The dispersion of a cylindrical particle ring by a blast or shock wave induces the formation of coherent structures which take the form of particle jets. A blast wave, issuing from the discharge of a planar shock wave at the exit of a conventional shock tube, is generated in the center of a granular medium ring initially confined inside a Hele-Shaw cell. With the present experimental setup, under impulsive acceleration, a solid particle-jet formation is observed in a quasi-two-dimensional configuration. The aim of the present investigation is to observe in detail the formation of very thin perturbations created around the external surface of the dispersed particle layer. By means of fast flow visualization with an appropriate recording window, we focus solely on the first instants during which the external particle ring becomes unstable. We find that the critical area of the destabilization of the external ring surface is constant regardless of the acceleration of the initial layer. Moreover, we observe in detail the external front perturbation wavelength, rendered dimensionless by the initial ring perimeter, and follow its evolution with the initial particle layer acceleration. We report this quantity to be constant regardless of the evolution of the initial particle layer acceleration. Finally, we can reasonably assert that external front perturbations depend solely on the material of the particles.

Effects of granular charge on flow and mixing

NASA Astrophysics Data System (ADS)

Shinbrot, T.; Herrmann, H. J.

2008-12-01

Sandstorms in the desert have long been reported to produce sparks and other electrical disturbances - indeed as long ago as 1850, Faraday commented on the peculiarities of granular charging during desert sandstorms. Similarly, lightning strikes within volcanic dust plumes have been repeatedly reported for over half a century, but remain unexplained. The problem of granular charging has applied, as well as natural, implications, for charged particle clouds frequently generate spectacularly devastating dust explosions in granular processing plants, and sand becomes strongly electrified by helicopters traveling in desert environments. The issue even has implications for missions to the Moon and to Mars, where charged dust degrades solar cells viability and clings to spacesuits, limiting the lifetime of their joints. Despite the wide-ranging importance of granular charging, even the simplest aspects of its causes remain elusive. To take one example, sand grains in the desert manage to charge one another despite having only similar materials to rub against over expanses of many miles - thus existing theories of charging due to material differences fail entirely to account for the observed charging of desert sands. In this talk, we describe recent progress made in identifying underlying causes of granular charging, both in desert-like environments and in industrial applications, and we examine effects of granular charging on flow, mixing and separation of common granular materials. We find that charging of identical grains can occur under simple laboratory conditions, and we make new predictions for the effects of this charging on granular behaviours.

Morphological and Biochemical Features of Cerebellar Cortex After Exposure to Zinc Oxide Nanoparticles: Possible Protective Role of Curcumin.

PubMed

Amer, Mona G; Karam, Rehab A

2018-03-25

Zinc oxide nanoparticles (ZnONPs) are widely used in the last decades. Therefore, investigation of its neurotoxic effect is important. This work aimed to investigate the potential adverse effects of ZnONPs on rat's cerebellar cortex and the possible neuroprotective role of curcumin (Cur). Forty male albino rats were randomly divided into four equal groups. Two groups were injected with ZnONPs and one group was previously received Cur before ZnONPs. At the end of the experiment, cerebellar tissue samples were prepared for histological, morphometric, immunohistochemical study, and tissue levels of oxidative stress markers and cytokine analysis. cerebellar damage is clearly visible with ZnONPs. Degeneration, loss, disorganization of cerebellar neurons was observed. Histopathological degeneration of Purkinje and granular cells together with loss of Nissl substance, astrocyte gliosis, and affection of cerebellar blood brain barrier were detected. Moreover, an apoptotic marker (caspase-3) was significantly expressed in Purkinje and granular layers together with elevated gene expression of P53 and COX-2 in cerebellar tissue of ZnONPs intoxicated group. Astrocyte gliosis and inflammatory markers IL-1, IL-6, and TNF-α were expressed significantly in ZnONPs intoxicated cerebellum. These changes were associated with evidence of cerebellar oxidative stress. Strikingly, treatment with Cur together with ZnONPs recorded morphological improvement, with increased number of Purkinje cells and decreased caspase +ve cells. These findings were confirmed by morphometric and statistical analysis. Cur ameliorates the deterious effect of ZnONPs on the cerebellar cortex through its antioxidant, antiapoptotic, and anti-inflammatory efficacies. Anat Rec, 2018. © 2018 Wiley Periodicals, Inc. © 2018 Wiley Periodicals, Inc.

Immunohistochemical study of Ulex europaeus agglutinin 1 (UEA-1) binding of megakaryocytes in bone marrow biopsy specimens: demonstration of heterogeneity in staining pattern reflecting the stages of differentiation.

PubMed

Liu, S M; Li, C Y

1996-01-01

During differentiation, megakaryocytes undergo nuclear endoreplication, an increase in cell size, cytoplasmic granulation, and release of platelets. The changes in highly lobulated nuclei with varying degree of polyploidy and increasing cell size are easily recognized morphologically. However, the actual cytoplasmic changes are more difficult to perceive morphologically. With the peroxidase-antiperoxidase (PAP) method using UEA-1 as the binding protein to the alpha-L-fucose of glycoprotein synthesized by megakaryocytes, we observed significant variation in cytoplasmic staining of megakaryocytes in routinely processed bone marrow biopsy sections. A total of 3344 megakaryocytes in bone marrow sections from 10 patients with nonhematologic diseases and from 10 patients with idiopathic thrombocytopenic purpura (ITP) was studied. According to the intensity and pattern of cytoplasmic staining, we divided megakaryocytes into at least six groups: (1) low granular (LG), (2) diffuse granular (DG), (3) diffuse dense granular (DDG), (4) marginal granular (MG), (5) denuded (DMK), and (6) endomitotic (EndoM). Most of the megakaryocytes were DG (mean, 42.75% +/- 19.21%) and DDG (mean, 50.25% +/- 21.23%). In correlation with nuclear morphology and cell size, it appears that substances binding to UEA-1 are located in the paranuclear region in early megakaryocytes and produce a low granular focal staining pattern (LG cells). Next, the granules spread throughout the cytoplasm (DG cells) and increase in quantity (DDG). This is followed by migration of granules to the periphery of the cytoplasm (MG cells) and is associated with the liberation of platelets and eventual formation of DMK megakaryocytes. Endomitosis, regulated by unknown factors, occurred in the MG stage. In comparing the group with nonhematologic disease (mean DG, 35.4% +/- 18.48%; DDG, 58.4% +/- 21.8%) and the group with ITP (mean DG, 50.1% +/- 17.82%; DDG, 42.1% +/- 18.12%), we found an increasing proportion of DG megakaryocytes in ITP, which suggests a left-shifted maturation of megakaryocytes. By understanding the staining pattern seen in the different stages of megakaryocytic differentiation, UEA-1 staining may be a practical method for studying megakaryocytopoiesis in routinely processed paraffin sections of bone marrow biopsy samples.

Stochastic phase of ventral furrow formation in the Drosophila embryo: cellular constriction chains, mechanical feedback, and robustness

NASA Astrophysics Data System (ADS)

Blawzdziewicz, Jerzy; Gao, Guo-Jie J.; Holcomb, Michael C.; Thomas, Jeffrey H.

The key process giving rise to ventral furrow formation (VFF) in Drosophila embryo is apical constriction of cells in the ventral region. The constriction produces negative spontaneous curvature of the cell layer. During the initial slower phase of VFF approximately 40% of cells constrict in a seemingly random order. We show that this initial phase of VFF does not depend on random uncorrelated events. Instead, constricted cell apices form well-defined correlated structures, i.e., cellular constriction chains (CCCs), indicative of strong spatial and directional correlations between the constriction events. We argue that this chain formation is a signature of mechanical signaling that coordinates apical constrictions through tensile stress. To gain insights into the mechanisms involved in this correlated constriction process, we propose an active granular fluid (AGF) model which considers a tissue as a collection of mechanically active, stress-responsive objects. Our AGF molecular dynamics simulations show that cell constriction sensitivity to tensile stress results in formation of CCCs whereas compressive-stress sensitivity leads to compact constricted cell clusters; the CCCs, which can penetrate less-active regions, increase the robustness of the VFF process.

Dense granular flow around a rigid or flexible intruder

NASA Astrophysics Data System (ADS)

Kolb, Evelyne; Adda-Bedia, Mokhtar

2012-02-01

We experimentally studied the flow of a dense granular material around an obstacle (rigid cylinder or flexible plate) placed in a 2 dimensional confined cell at a packing fraction near the 2D jamming threshold. In the case of the rigid obstacle, the displacement field of grains as well as the drag force experienced by the obstacle were simultaneously recorded and a parametric study was done by changing the cell size, the intruder diameter or the packing fraction. The drag force experienced by the intruder and the formation of a wake behind the obstacle were very sensitive to the approach to jamming. The same experimental set-up was adapted to a flexible intruder and coupling between the granular flow and fibre deflexion were imaged. The deformation of the fibre could be compared with theoretical predictions from elastica.

Primary malignant perivascular epithelioid cell neoplasm (PEComa) of the bone mimicking granular cell tumor in core biopsy: A case report and literature review

PubMed Central

Sadigh, Sam; Shah, Preya; Weber, Kristy; Sebro, Ronnie; Zhang, Paul J.

2018-01-01

The present study investigated the case of a 46-year-old female with primary malignant perivascular epithelioid cell neoplasm (PEComa) of the femur. The patient presented with a 5-month history of right distal thigh pain following trauma. Radiographs of the right distal femur revealed a mixed lytic and sclerotic lesion with subtle areas of cortical destruction and soft tissue extension, consistent with an aggressive tumor. A core biopsy revealed an epithelioid tumor with granular cell features, but a definitive diagnosis could not be made. Due to the aggressive features on radiologic evaluation, the patient underwent a resection of the distal femur and reconstruction with a distal femoral megaprosthesis and hinged knee replacement. The post-resection pathology led to a final diagnosis of primary bone PEComa, with histologic features including epithelioid, granular cell and spindled cell morphologies and biphasic immunoreactivity for melanocytic and smooth muscle markers. The large tumor size (>5 cm), rapid mitotic rate, infiltrative growth pattern, high nuclear grade and cellularity, and the presence of necrosis rendered this a malignant PEComa. The present study discussed the case, including radiographic (radiographs, magnetic resonance imaging and positron emission tomography scans) and histologic appearance and a literature review. PMID:29435023

Time Shared Optical Network (TSON): a novel metro architecture for flexible multi-granular services.

PubMed

Zervas, Georgios S; Triay, Joan; Amaya, Norberto; Qin, Yixuan; Cervelló-Pastor, Cristina; Simeonidou, Dimitra

2011-12-12

This paper presents the Time Shared Optical Network (TSON) as metro mesh network architecture for guaranteed, statistically-multiplexed services. TSON proposes a flexible and tunable time-wavelength assignment along with one-way tree-based reservation and node architecture. It delivers guaranteed sub-wavelength and multi-granular network services without wavelength conversion, time-slice interchange and optical buffering. Simulation results demonstrate high network utilization, fast service delivery, and low end-to-end delay on a contention-free sub-wavelength optical transport network. In addition, implementation complexity in terms of Layer 2 aggregation, grooming and optical switching has been evaluated. © 2011 Optical Society of America

A Grey Wolf Optimizer for Modular Granular Neural Networks for Human Recognition

PubMed Central

Sánchez, Daniela; Melin, Patricia

2017-01-01

A grey wolf optimizer for modular neural network (MNN) with a granular approach is proposed. The proposed method performs optimal granulation of data and design of modular neural networks architectures to perform human recognition, and to prove its effectiveness benchmark databases of ear, iris, and face biometric measures are used to perform tests and comparisons against other works. The design of a modular granular neural network (MGNN) consists in finding optimal parameters of its architecture; these parameters are the number of subgranules, percentage of data for the training phase, learning algorithm, goal error, number of hidden layers, and their number of neurons. Nowadays, there is a great variety of approaches and new techniques within the evolutionary computing area, and these approaches and techniques have emerged to help find optimal solutions to problems or models and bioinspired algorithms are part of this area. In this work a grey wolf optimizer is proposed for the design of modular granular neural networks, and the results are compared against a genetic algorithm and a firefly algorithm in order to know which of these techniques provides better results when applied to human recognition. PMID:28894461

A Grey Wolf Optimizer for Modular Granular Neural Networks for Human Recognition.

PubMed

Sánchez, Daniela; Melin, Patricia; Castillo, Oscar

2017-01-01

A grey wolf optimizer for modular neural network (MNN) with a granular approach is proposed. The proposed method performs optimal granulation of data and design of modular neural networks architectures to perform human recognition, and to prove its effectiveness benchmark databases of ear, iris, and face biometric measures are used to perform tests and comparisons against other works. The design of a modular granular neural network (MGNN) consists in finding optimal parameters of its architecture; these parameters are the number of subgranules, percentage of data for the training phase, learning algorithm, goal error, number of hidden layers, and their number of neurons. Nowadays, there is a great variety of approaches and new techniques within the evolutionary computing area, and these approaches and techniques have emerged to help find optimal solutions to problems or models and bioinspired algorithms are part of this area. In this work a grey wolf optimizer is proposed for the design of modular granular neural networks, and the results are compared against a genetic algorithm and a firefly algorithm in order to know which of these techniques provides better results when applied to human recognition.

Poly(ethylene imine)-based granular sorbents by a new process of templated gel-filling. High capacity and selectivity of copper sorption in acidic and alkaline media

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chanda, M.; Rempel, G.L.

A new process has been developed for making granular gel-type sorbents from chelating resins using metal ion as template. Named as templated gel-filling, the process uses the chosen metal as templating host ion on high-surface-area silica to build a templated gel layer from a solution of the chelating resin in a suitable solvent in which the resin is soluble but its metal complex is insoluble. After cross-linking the templated gel layer, the silica support is removed by alkali to produce a hollow shell of the templated gel. The shells are then soaked in a concentrated aqueous solution of the samemore » metal ion and suspended in the same resin solution to afford gel-filling. The shells thus filled with metal-templated gel are treated with cross-linking agent, followed by acid to remove the template ion and activate the resin for metal sorption. Poly(ethyleneimine) and its partially ethylated derivative have been used to produce granular gel-type sorbents by this process, with Cu(II) as the template ion. These sorbents are found to offer high capacity and selectivity for copper over nickel, cobalt, and zinc in both acidic and alkaline media. Containing a relatively high fraction of imbibed water, the sorbents exhibit markedly enhanced rate behavior, in both sorption and stripping.« less

Silicon-germanium and platinum silicide nanostructures for silicon based photonics

NASA Astrophysics Data System (ADS)

Storozhevykh, M. S.; Dubkov, V. P.; Arapkina, L. V.; Chizh, K. V.; Mironov, S. A.; Chapnin, V. A.; Yuryev, V. A.

2017-05-01

This paper reports a study of two types of silicon based nanostructures prospective for applications in photonics. The first ones are Ge/Si(001) structures forming at room temperature and reconstructing after annealing at 600°C. Germanium, being deposited from a molecular beam at room temperature on the Si(001) surface, forms a thin granular film composed of Ge particles with sizes of a few nanometers. A characteristic feature of these films is that they demonstrate signs of the 2 x 1 structure in their RHEED patterns. After short-term annealing at 600°C under the closed system conditions, the granular films reconstruct to heterostructures consisting of a Ge wetting layer and oval clusters of Ge. A mixed type c(4x2) + p(2x2) reconstruction typical to the low-temperature MBE (Tgr < 600°C) forms on the wetting layer. Long-term annealing of granular films at the same conditions results in formation of c(4x2)-reconstructed wetting layer typical to high-temperature MBE (Tgr < 600°C) and huge clusters of Ge. The other type of the studied nanostructures is based on Pt silicides. This class of materials is one of the friendliest to silicon technology. But as silicide film thickness reaches a few nanometers, low resistivity becomes of primary importance. Pt3Si has the lowest sheet resistance among the Pt silicides. However, the development of a process of thin Pt3Si films formation is a challenging task. This paper describes formation of a thin Pt3Si/Pt2Si structures at room temperature on poly-Si films. Special attention is paid upon formation of poly-Si and amorphous Si films on Si3N4 substrates at low temperatures.

Shear-induced crystallization of a dense rapid granular flow: hydrodynamics beyond the melting point.

PubMed

Khain, Evgeniy; Meerson, Baruch

2006-06-01

We investigate shear-induced crystallization in a very dense flow of monodisperse inelastic hard spheres. We consider a steady plane Couette flow under constant pressure and neglect gravity. We assume that the granular density is greater than the melting point of the equilibrium phase diagram of elastic hard spheres. We employ a Navier-Stokes hydrodynamics with constitutive relations all of which (except the shear viscosity) diverge at the crystal-packing density, while the shear viscosity diverges at a smaller density. The phase diagram of the steady flow is described by three parameters: an effective Mach number, a scaled energy loss parameter, and an integer number m: the number of half-oscillations in a mechanical analogy that appears in this problem. In a steady shear flow the viscous heating is balanced by energy dissipation via inelastic collisions. This balance can have different forms, producing either a uniform shear flow or a variety of more complicated, nonlinear density, velocity, and temperature profiles. In particular, the model predicts a variety of multilayer two-phase steady shear flows with sharp interphase boundaries. Such a flow may include a few zero-shear (solidlike) layers, each of which moving as a whole, separated by fluidlike regions. As we are dealing with a hard sphere model, the granulate is fluidized within the "solid" layers: the granular temperature is nonzero there, and there is energy flow through the boundaries of the solid layers. A linear stability analysis of the uniform steady shear flow is performed, and a plausible bifurcation diagram of the system, for a fixed m, is suggested. The problem of selection of m remains open.

CD20dim-positive T-cell large granular lymphocytic leukemia in a patient with concurrent hairy cell leukemia and plasma cell myeloma

PubMed Central

Xu, Xiangdong; Broome, Elizabeth H; Rashidi, Hooman H; South, Sarah T; Dell'Aquila, Marie L; Wang, Huan-You

2010-01-01

We report a CD20dim- positive T-cell large granular lymphocytic (T-LGL) leukemia in a patient with concurrent hairy cell leukemia and plasma cell myeloma. This patient was first diagnosed with T-LGL leukemia with dim CD20 expression, which by itself was a rare entity. He received no treatment for T-LGL leukemia. The patient later developed a hairy cell leukemia, which went into complete clinical remission after one cycle of 2-CdA. Five years later, he was diagnosed with a third malignancy, plasma cell myeloma. Complex cytogenetic aberrancies were present at the time when plasma cell myeloma was diagnosed. This is the first report, to the best of our knowledge, in the English literature with the aforementioned three distinct hematopoietic malignancies in one patient. PMID:21151394

Hyperandrogenism from an ovarian interstitial-cell tumor in an alpaca.

PubMed

Gilbert, Rosanne; Kutzler, Michelle; Valentine, Beth A; Semevolos, Stacy

2006-11-01

An 8-year-old intact female Huacaya alpaca (Lama pacos) was presented for recent development of male behavior. Serum testosterone concentration was determined to be 969.1 pg/ml by using radioimmunoassay, while the range in 33 healthy female adult intact alpacas was 11.7-62.1 pg/ml. An ovarian mass was suspected, and an exploratory laparotomy was performed. A tan mass was present on the left ovary. Histologically, the mass was composed of closely packed, plump, polygonal cells with central round nuclei with granular chromatin and abundant eosinophilic finely granular to vesiculate cytoplasm. An ovarian benign interstitial (Leydig) cell tumor was diagnosed.

Effects of intense tone exposure on choline acetyltransferase activity in the hamster cochlear nucleus.

PubMed

Jin, Yong-Ming; Godfrey, Donald A; Wang, Jie; Kaltenbach, James A

2006-01-01

Choline acetyltransferase (ChAT) activity has been mapped in the cochlear nucleus (CN) of control hamsters and hamsters that had been exposed to an intense tone. ChAT activity in most CN regions of hamsters was only a third or less of the activity in rat CN, but in granular regions ChAT activity was similar in both species. Eight days after intense tone exposure, average ChAT activity increased on the tone-exposed side as compared to the opposite side, by 74% in the anteroventral CN (AVCN), by 55% in the granular region dorsolateral to it, and by 74% in the deep layer of the dorsal CN (DCN). In addition, average ChAT activity in the exposed-side AVCN and fusiform soma layer of DCN was higher than in controls, by 152% and 67%, respectively. Two months after exposure, average ChAT activity was still 53% higher in the exposed-side deep layer of DCN as compared to the opposite side. Increased ChAT activity after intense tone exposure may indicate that this exposure leads to plasticity of descending cholinergic innervation to the CN, which might affect spontaneous activity in the DCN that has been associated with tinnitus.

Evidence for a terminal differentiation process in the rat liver.

PubMed

Sigal, S H; Gupta, S; Gebhard, D F; Holst, P; Neufeld, D; Reid, L M

1995-07-01

In rapidly renewing epithelia, such as skin and gut, as well as hemopoietic cells and stromal fibroblasts, the process of progenitor cell maturation, terminal differentiation and senescence from cells of a fetal phenotype is strikingly similar. To examine hepatocellular maturation, we studied embryonic, suckling and young adult rat liver cells with multiparametric fluorescence activated cell sorting (FACS), after exclusion of hemopoietic, endothelial, Kupffer, and nonviable cells. With maturation, cell granularity and autofluorescence exponentially increased from fetal liver to suckling and adult liver as the proportion of S phase cells progressively declined from 33.8% +/- 1.3% to 4.9% +/- 2.8% and 1.1% +/- 0.6% (P < 0.05), respectively. In liver from fetal and suckling rats, all hepatocytes were mononuclear and contained diploid DNA whereas 21.2% +/- 5.9% hepatocytes in adult liver were binucleated. Analysis of nuclear DNA content in adult hepatocytes demonstrated that 53.3% +/- 3.9% of the nuclei were diploid, 43.6% +/- 3.5% tetraploid and 0.5 +/- 0.6% octaploid. However, in the adult liver, small, mononuclear cells were also present with granularity and autofluorescence comparable to fetal hepatoblasts, as well as glucose-6-phosphatase activity, diploid DNA in 89.0% +/- 2.1% of the nuclei, and with increased granularity in culture. Since general features of terminal cellularity differentiation and senescence include cessation of mitotic activity, polyploidy and accumulation of autofluorescent secondary lysosomes, our data suggest that liver cells too undergo a process of terminal differentiation.

Characterization of highly pathogenic avian influenza H5N8 virus from Egyptian domestic waterfowl in 2017.

PubMed

Anis, Anis; AboElkhair, Mohammed; Ibrahim, Mahmoud

2018-08-01

In 2016, the highly pathogenic avian influenza (HPAI) H5N8 virus was detected in wild birds for the first time in Egypt. In the present study, we identified the HPAI virus H5N8 of clade 2.3.4.4 from domestic waterfowl in Egypt, suggesting its transmission to the domestic poultry from the migratory birds. Based on partial haemagglutinin gene sequence, this virus has a close genetic relationship with subtype H5N8 viruses circulating in Asia and Europe. Pathologically, H5N8 virus in hybrid duck induced nervous signs accompanied by encephalomalacia, haemorrhages, nonsuppurative encephalitis and nonsuppurative vasculitis. The granular layer of cerebellum showed multifocal areas of hydropic degeneration and the Purkinje cell neurons were necrotized or lost. Additionally, the lung, kidney and spleen were congested, and necrotizing pancreatitis was also observed. The co-circulation of both HPAI H5N1 and H5N8 subtypes with the low pathogenic avian influenza H9N2 subtype complicate the control of avian influenza in Egypt with the possibility of emergence of new reassortant viruses. Therefore, continuous monitoring with implementation of strict control measures is required. Research highlights HPAI H5N8 virus clade 2.3.4.4 was detected in domestic ducks and geese in Egypt in 2017. Phylogenetically, the virus was closely related to HPAI H5N8 viruses identified in Asia and Europe Nonsuppurative encephalitis was widely observed in HPAI H5N8 virus-infected ducks. Degeneration of the cerebellar granular layer was found in most of the brain tissues examined.

Progressive magnetic softening of ferromagnetic layers in multilayer ferromagnet-nonmagnet systems and the role of granularity

NASA Astrophysics Data System (ADS)

Sahu, Siddharth S.; Siva, Vantari; Pradhan, Paresh C.; Nayak, Maheswar; Senapati, Kartik; Sahoo, Pratap K.

2017-06-01

We report a study of the structural and magnetic behavior of the topmost magnetic layer in a ferromagnet-nonmagnet (Co-Au) multilayer system. Glancing angle X-ray diffraction measurements performed on a series of multilayers showed a gradual decrease in the grain size of the topmost magnetic layer with the increasing number of bilayers. Concurrently, the magnetic hardness and magneto-crystalline anisotropy of the top Co layer were found to decrease, as observed by magneto-optical Kerr effect measurements. This magnetic softening has been discussed in the light of Herzer's random anisotropy model. Micromagnetic simulations of the multilayer system also corroborated these observations.

Pattern formation of frictional fingers in a gravitational potential

NASA Astrophysics Data System (ADS)

Eriksen, Jon Alm; Toussaint, Renaud; Mâløy, Knut Jørgen; Flekkøy, Eirik; Galland, Olivier; Sandnes, Bjørnar

2018-01-01

Aligned finger structures, with a characteristic width, emerge during the slow drainage of a liquid-granular mixture in a tilted Hele-Shaw cell. A transition from vertical to horizontal alignment of the finger structures is observed as the tilting angle and the granular density are varied. An analytical model is presented, demonstrating that the alignment properties are the result of the competition between fluctuating granular stresses and the hydrostatic pressure. The dynamics is reproduced in simulations. We also show how the system explains patterns observed in nature, created during the early stages of a dike formation.

Transient behavior of granular materials with symmetric conditions for tumbler shapes and fill fractions

NASA Astrophysics Data System (ADS)

Pohlman, Nicholas; Si, Yun

2014-11-01

The typical granular motion in circular tumblers is considered steady-state since there are no features to disrupt the top surface layer dimension. In polygon tumblers, however, the flowing layer is perpetually changing length, which creates unsteady conditions with corresponding change in the flow behavior. Prior work showed the minimization of free surface energy is independent of tumbler dimension, particle size, and rotation rate. This subsequent research reports on experiments where dimensional symmetry of the free surface in triangular and square tumblers with varying fill fractions do not necessarily produce the symmetric flow behaviors. Results of the quasi-2D tumbler experiment show that other dimensions aligned with gravity and the instantaneous free surface influence the phase when extrema for angle of repose and other flow features occur. The conclusion is that 50% fill fraction may produce geometric symmetry of dimensions, but the symmetry point of flow likely occurs at a lower fill fraction.

Shear test on viscoelastic granular material using Contact Dynamics simulations

NASA Astrophysics Data System (ADS)

Quezada, Juan Carlos; Sagnol, Loba; Chazallon, Cyrille

2017-06-01

By means of 3D contact dynamic simulations, the behavior of a viscoelastic granular material under shear loading is investigated. A viscoelastic fluid phase surrounding the solid particles is simulated by a contact model acting between them. This contact law was implemented in the LMGC90 software, based on the Burgers model. This model is able to simulate also the effect of creep relaxation. To validate the proposed contact model, several direct shear tests were performed, experimentally and numerically using the Leutner device. The numerical samples were created using spheres with two particle size distribution, each one identified for two layers from a road structure. Our results show a reasonable agreement between experimental and numerical data regarding the strain-stress evolution curves and the stress levels measured at failure. The proposed model can be used to simulate the mechanical behavior of multi-layer road structure and to study the influence of traffic on road deformation, cracking and particles pull-out induced by traffic loading.

Parallel Program Systems for the Analysis of Wave Processes in Elastic-Plastic, Granular, Porous and Multi-Blocky Media

NASA Astrophysics Data System (ADS)

Sadovskaya, Oxana; Sadovskii, Vladimir

2017-04-01

Under modeling the wave propagation processes in geomaterials (granular and porous media, soils and rocks) it is necessary to take into account the structural inhomogeneity of these materials. Parallel program systems for numerical solution of 2D and 3D problems of the dynamics of deformable media with constitutive relationships of rather general form on the basis of universal mathematical model describing small strains of elastic, elastic-plastic, granular and porous materials are worked out. In the case of an elastic material, the model is reduced to the system of equations, hyperbolic by Friedrichs, written in terms of velocities and stresses in a symmetric form. In the case of an elastic-plastic material, the model is a special formulation of the Prandtl-Reuss theory in the form of variational inequality with one-sided constraints on the stress tensor. Generalization of the model to describe granularity and the collapse of pores is obtained by means of the rheological approach, taking into account different resistance of materials to tension and compression. Rotational motion of particles in the material microstructure is considered within the framework of a mathematical model of the Cosserat continuum. Computational domain may have a blocky structure, composed of an arbitrary number of layers, strips in a layer and blocks in a strip from different materials with self-consistent curvilinear interfaces. At the external boundaries of computational domain the main types of dissipative boundary conditions in terms of velocities, stresses or mixed boundary conditions can be given. Shock-capturing algorithm is proposed for implementation of the model on supercomputers with cluster architecture. It is based on the two-cyclic splitting method with respect to spatial variables and the special procedures of the stresses correction to take into account plasticity, granularity or porosity of a material. An explicit monotone ENO-scheme is applied for solving one-dimensional systems of equations at the stages of splitting method. The parallelizing of computations is carried out using the MPI library and the SPMD technology. The data exchange between processors occurs at step "predictor" of the finite-difference scheme. Program systems allow simulate the propagation of waves produced by external mechanical effects in a medium, aggregated of arbitrary number of heterogeneous blocks. Some computations of dynamic problems with and without taking into account the moment properties of a material were performed on clusters of ICM SB RAS (Krasnoyarsk) and JSCC RAS (Moscow). Parallel program systems 2Dyn_Granular, 3Dyn_Granular, 2Dyn_Cosserat, 3Dyn_Cosserat and 2Dyn_Blocks_MPI for numerical solution of 2D and 3D elastic-plastic problems of the dynamics of granular media and problems of the Cosserat elasticity theory, as well as for modeling of the dynamic processes in multi-blocky media with pliant viscoelastic, porous and fluid-saturated interlayers on cluster systems were registered by Rospatent.

Immunohistochemical detection of autophagy-related microtubule-associated protein 1 light chain 3 (LC3) in the cerebellums of dogs naturally infected with canine distemper virus.

PubMed

Kabak, Y B; Sozmen, M; Yarim, M; Guvenc, T; Karayigit, M O; Gulbahar, M Y

2015-01-01

We investigated the expression of microtubule-associated protein 1 light chain 3 (LC3) protein in the cerebellums of dogs infected with canine distemper virus (CDV) using immunohistochemistry to detect autophagy. The cerebellums of 20 dogs infected with CDV were used. Specimens showing demyelination of white matter were considered to have an acute infection, whereas specimens showing signs of severe perivascular cuffing and demyelination of white matter were classified as having chronic CDV. Cerebellar sections were immunostained with CDV and LC3 antibodies. The cytoplasm of Purkinje cells, granular layer cells, motor neurons in large cerebellar ganglia and some neurons in white matter were positive for the LC3 antibody in both the control and CDV-infected dogs. In the infected cerebellums, however, white matter was immunostained more intensely, particularly the neurons and gemistocytic astrocytes in the demyelinated areas, compared to controls. Autophagy also was demonstrated in CDV-positive cells using double immunofluorescence staining. Our findings indicate that increased autophagy in the cerebellum of dogs naturally infected with CDV may play a role in transferring the virus from cell to cell.

Activation of Postnatal Neural Stem Cells Requires Nuclear Receptor TLX

PubMed Central

Niu, Wenze; Zou, Yuhua; Shen, ChengCheng; Zhang, Chun-Li

2011-01-01

Neural stem cells (NSCs) continually produce new neurons in postnatal brains. However, the majority of these cells stay in a non-dividing, inactive state. The molecular mechanism that is required for these cells to enter proliferation still remains largely unknown. Here, we show that nuclear receptor TLX (NR2E1) controls the activation status of postnatal NSCs in mice. Lineage tracing indicates that TLX-expressing cells give rise to both activated and inactive postnatal NSCs. Surprisingly, loss of TLX function does not result in spontaneous glial differentiation, but rather leads to a precipitous age-dependent increase of inactive cells with marker expression and radial morphology for NSCs. These inactive cells are mis-positioned throughout the granular cell layer of the dentate gyrus during development and can proliferate again after reintroducing ectopic TLX. RNA-seq analysis of sorted NSCs revealed a TLX-dependent global expression signature, which includes the p53 signaling pathway. TLX regulates p21 expression in a p53-dependent manner and acute removal of p53 can rescue the proliferation defect of TLX-null NSCs in culture. Together, these findings suggest that TLX acts as an essential regulator that ensures the proliferative ability of postnatal NSCs by controlling their activation through genetic interaction with p53 and other signaling pathways. PMID:21957244

Activation of postnatal neural stem cells requires nuclear receptor TLX.

PubMed

Niu, Wenze; Zou, Yuhua; Shen, Chengcheng; Zhang, Chun-Li

2011-09-28

Neural stem cells (NSCs) continually produce new neurons in postnatal brains. However, the majority of these cells stay in a nondividing, inactive state. The molecular mechanism that is required for these cells to enter proliferation still remains largely unknown. Here, we show that nuclear receptor TLX (NR2E1) controls the activation status of postnatal NSCs in mice. Lineage tracing indicates that TLX-expressing cells give rise to both activated and inactive postnatal NSCs. Surprisingly, loss of TLX function does not result in spontaneous glial differentiation, but rather leads to a precipitous age-dependent increase of inactive cells with marker expression and radial morphology for NSCs. These inactive cells are mispositioned throughout the granular cell layer of the dentate gyrus during development and can proliferate again after reintroduction of ectopic TLX. RNA-seq analysis of sorted NSCs revealed a TLX-dependent global expression signature, which includes the p53 signaling pathway. TLX regulates p21 expression in a p53-dependent manner, and acute removal of p53 can rescue the proliferation defect of TLX-null NSCs in culture. Together, these findings suggest that TLX acts as an essential regulator that ensures the proliferative ability of postnatal NSCs by controlling their activation through genetic interaction with p53 and other signaling pathways.

Incorporation of new neurons in the olfactory bulb after paced mating in the female rat.

PubMed

Alvarado-Martínez, R; Paredes, R G

2018-05-02

One of the regions that constantly produces neurogenesis in the adult brain is the subventricular zone (SVZ), whose new cells migrate to the olfactory bulbs (OB). When the females regulate the copulatory events (paced mating) the number of new cells in the SVZ increases, as well as those observed in the OB 15 days later. However, no changes were observed in the number of cells 45 days after the females paced the sexual interaction. Constant sensory stimulation is an important promoter of cell survival in the OB circuit. Hence, we increased the number of mating sessions in this study to cover the period where stimulation of the new cells is critical for their incorporation into pre-existing circuits in the OB. Ovariectomized female Wistar rats, were injected with the mitotic marker 5-bromo-2'-deoxyuridine (BrdU, 100 mg/kg, per injection) before, at the end and one hour after mating. Sexual behavior was recorded for 1 h in 10 weekly sessions. After the last mating session, brain sections were processed to determine BrdU immunoreactivity. Our results indicate that females that paced the sexual interaction for 10 sessions had a higher number of cells in the glomerular layer (GL) of the accessory olfactory bulb (AOB) and a higher number of neurons in the granular layer (GrL) of the main olfactory bulb (MOB) in comparison to the control group. These results indicate that continued sexual interaction contributes to the integration of new cells and neurons, induced in the first sexual experience, into pre-exiting circuits of the OB. Copyright © 2018 Elsevier B.V. All rights reserved.

CAR-pNK Cell Immunotherapy in CD7 Positive Leukemia and Lymphoma

ClinicalTrials.gov

2016-12-04

Acute Myeloid Leukemia; Precursor T-Cell Lymphoblastic Leukemia-Lymphoma; T-cell Prolymphocytic Leukemia; T-cell Large Granular Lymphocytic Leukemia; Peripheral T-cell Lymphoma, NOS; Angioimmunoblastic T-cell Lymphoma; Extranodal NK/T-cell Lymphoma, Nasal Type; Enteropathy-type Intestinal T-cell Lymphoma; Hepatosplenic T-cell Lymphoma

Developmental Injury to the Cerebellar Cortex Following Hydroxyurea Treatment in Early Postnatal Life: An Immunohistochemical and Electron Microscopic Study.

PubMed

Martí, Joaquín; Molina, Vanesa; Santa-Cruz, M C; Hervás, José P

2017-02-01

Postnatal development of the cerebellar cortex was studied in rats administered with a single dose (2 mg/g) of the cytotoxic agent hydroxyurea (HU) on postnatal day (P) 9 and collected at appropriate times ranging from 6 h to 45 days. Quantification of several parameters such as the density of pyknotic, mitotic, BrdU-positive, and vimentin-stained cells revealed that HU compromises the survival of the external granular layer (EGL) cells. Moreover, vimentin immunocytochemistry revealed overexpression and thicker immunoreactive glial processes in HU-treated rats. On the other hand, we also show that HU leads to the activation of apoptotic cellular events, resulting in a substantial number of dying EGL cells, as revealed by TUNEL staining and at the electron microscope level. Additionally, we quantified several features of the cerebellar cortex of rats exposed to HU in early postnatal life and collected in adulthood. Data analysis indicated that the analyzed parameters were less pronounced in rats administered with this agent. Moreover, we observed several alterations in the cerebellar cortex cytoarchitecture of rats injected with HU. Anomalies included ectopic placement of Purkinje cells and abnormities in the dendritic arbor of these macroneurons. Ectopic granule cells were also found in the molecular layer. These findings provide a clue for investigating the mechanisms of HU-induced toxicity during the development of the central nervous system. Our results also suggest that it is essential to avoid underestimating the adverse effects of this hydroxylated analog of urea when administered during early postnatal life.

A typical band-shaped calcific keratopathy with keratocyte changes.

PubMed Central

Dark, A J; Proctor, J

1982-01-01

The clinical features of a patient with atypical band keratopathy are described. Histochemical and electron probe analyses indicate that the granular deposits in Bowman's layer contain calcium and phosphate. An unusual feature in this patient was the presence of severe keratocyte degeneration; its possible role in the pathogenesis of this condition is discussed. Exfoliation of the calcified Bowman's layer appears to have been the basis for severe attacks of recurrent ocular pain. Images PMID:7074004

Cell proliferation and apoptosis during histogenesis of the guinea pig and rabbit cerebellar cortex.

PubMed

Lossi, Laura; Coli, Alessandra; Giannessi, Elisabetta; Stornelli, Maria Rita; Marroni, Paolo

2002-01-01

Cell proliferation and apoptosis are essential for development of the nervous system. In this study we have investigated the histogenesis of the cerebellar cortex in guinea pig (a precocial species) and rabbit (an altricial species) at different stages of pregnancy and postnatal life. Proliferating cells were identified after labeling with antibodies against the proliferating cell nuclear antigen (PCNA) and/or the Ki-67 antigen. Apoptotic cells were visualized in situ by the TUNEL method and by immunodetection of cleaved caspase 3 and 9. In guinea pigs, both proliferating and apoptotic cells were detected during pre-natal life (E0-E40). Conversely, cell proliferation and apoptosis in rabbits were temporally restricted to early postnatal weeks (P0-P20). In both species cell proliferation was mainly linked to differentiation and migration of the granule cells. In both species, the majority of cells undergoing programmed cell death likely corresponded to granule cells. They were mainly detected in the external granular layer, and were by far more common than previously reported in other locations of the postnatal brain. This study shows that apoptosis is a shared process of cell death during cerebellar development in both altricial and precocial animals, and that there is a direct spatial and temporal correlation between cell proliferation and death in two mammals with different time tables in cerebellar maturation.

Mechanics of Granular Materials (MGM) Test Cell

NASA Technical Reports Server (NTRS)

2000-01-01

A test cell for Mechanics of Granular Materials (MGM) experiment is tested for long-term storage with water in the system as plarned for STS-107. This view shows the compressed sand column with the protective water jacket removed. Sand and soil grains have faces that can cause friction as they roll and slide against each other, or even cause sticking and form small voids between grains. This complex behavior can cause soil to behave like a liquid under certain conditions such as earthquakes or when powders are handled in industrial processes. Mechanics of Granular Materials (MGM) experiments aboard the Space Shuttle use the microgravity of space to simulate this behavior under conditons that cannot be achieved in laboratory tests on Earth. MGM is shedding light on the behavior of fine-grain materials under low effective stresses. Applications include earthquake engineering, granular flow technologies (such as powder feed systems for pharmaceuticals and fertilizers), and terrestrial and planetary geology. Nine MGM specimens have flown on two Space Shuttle flights. Another three are scheduled to fly on STS-107. The principal investigator is Stein Sture of the University of Colorado at Boulder. Credit: University of Colorado at Boulder

Mechanics of Granular Materials (MGM) Cell

NASA Technical Reports Server (NTRS)

1996-01-01

One of three Mechanics of Granular Materials (MGM) test cells after flight on STS-79 and before impregnation with resin. Note that the sand column has bulged in the middle, and that the top of the column is several inches lower than the top of the plastic enclosure. Sand and soil grains have faces that can cause friction as they roll and slide against each other, or even cause sticking and form small voids between grains. This complex behavior can cause soil to behave like a liquid under certain conditions such as earthquakes or when powders are handled in industrial processes. Mechanics of Granular Materials (MGM) experiments aboard the Space Shuttle use the microgravity of space to simulate this behavior under conditons that carnot be achieved in laboratory tests on Earth. MGM is shedding light on the behavior of fine-grain materials under low effective stresses. Applications include earthquake engineering, granular flow technologies (such as powder feed systems for pharmaceuticals and fertilizers), and terrestrial and planetary geology. Nine MGM specimens have flown on two Space Shuttle flights. Another three are scheduled to fly on STS-107. The principal investigator is Stein Sture of the University of Colorado at Boulder. Credit: University of Colorado at Boulder

Mechanics of Granular Materials (MGM) Test Cell

NASA Technical Reports Server (NTRS)

2000-01-01

A test cell for Mechanics of Granular Materials (MGM) experiment is tested for long-term storage with water in the system as plarned for STS-107. This view shows the top of the sand column with the metal platten removed. Sand and soil grains have faces that can cause friction as they roll and slide against each other, or even cause sticking and form small voids between grains. This complex behavior can cause soil to behave like a liquid under certain conditions such as earthquakes or when powders are handled in industrial processes. Mechanics of Granular Materials (MGM) experiments aboard the Space Shuttle use the microgravity of space to simulate this behavior under conditons that cannot be achieved in laboratory tests on Earth. MGM is shedding light on the behavior of fine-grain materials under low effective stresses. Applications include earthquake engineering, granular flow technologies (such as powder feed systems for pharmaceuticals and fertilizers), and terrestrial and planetary geology. Nine MGM specimens have flown on two Space Shuttle flights. Another three are scheduled to fly on STS-107. The principal investigator is Stein Sture of the University of Colorado at Boulder. Credit: University of Colorado at Boulder

Apoptosis in the cerebellum of dogs with distemper.

PubMed

Moro, L; Martins, A S; Alves, C M; Santos, F G A; Del Puerto, H L; Vasconcelos, A C

2003-06-01

Canine distemper virus (CDV) may induce multifocal demyelination in the central nervous system of infected dogs. The pathogenesis of this process is not clear. The present work identifies the presence of apoptotic cells in white and grey matter of dogs'cerebellum, naturally infected with CDV. Fifteen dogs with clinical signs of canine distemper that tested positive for CDV nucleoprotein were used. Brain specimens were processed and embedded in paraffin. Sections 5 microm thick were stained with hematoxylin-eosin and Shorr. Other sections were submitted to TUNEL reaction and to immunohistochemistry for CDV nucleoprotein detection. Acute and chronic demyelinated plaques were observed in the white matter, while apoptosis occurred particularly in the granular layer of grey matter. Apoptosis seems to play an important role in the pathogenesis of canine distemper demyelination.

Aprosencephaly with otocephaly in a lamb (Ovis aries).

PubMed

Brachthäuser, L; Klumpp, S; Hecht, W; Kuchelmeister, K; Reinacher, M; Ebbert, W; Herden, C

2012-11-01

Aprosencephaly is a rare condition in veterinary and human medicine characterized by the complete absence of telencephalon and diencephalon. Some cases are accompanied by a facial dysmorphism designated as otocephaly. A stillborn lamb had splanchnocranial anomalies that were classified by computed tomography, magnetic resonance imaging, and pathologic examination as aprosencephaly and otocephaly. The brain included parts of the cerebellum and brainstem but no telencephalon, diencephalon, or mesencephalon. The cerebellum had a structurally normal cortex with expression of neuronal nuclear antigen in the inner and doublecortin in the outer granular cell layers, as well as an irregularly situated nucleus dentatus. Aprosencephaly with otocephaly has been described in mice with heterozygous mutations in the Otx2 gene; however, no causative polymorphisms were detected in the Otx2 gene region of this lamb.

Lift on side by side intruders of various geometries within a granular flow

NASA Astrophysics Data System (ADS)

Acevedo-Escalante, M. F.; Caballero-Robledo, G. A.

2017-06-01

Obstacles within fluids have been widely used in engineering and in physics to study hydrodynamic interactions. In granular matter, objects within a granular flow have helped to understand fundamental features of drag and lift forces. In our group, we have studied numerically the flow mediated interaction between two static disks within a vertical granular flow in a two-dimensional container where the flow velocity and the distance between obstacles were varied. Attractive and repulsive forces were found depending on flow velocity and separation between intruders. The simulations evidenced a relationship between the average flow velocity in a specific section ahead of the obstacles and the attractive-repulsive lift. On the other hand, it was showed that the lift force on an object dragged within a granular medium depends on the shape of the intruder. Here we present experimental results of the interaction between two side-by-side intruders of different shapes within a vertical granular flow. We built a quasi-two-dimensional container in which we placed the intruders and using load cells we measured lift and drag forces during the discharge process for different flow velocities.

Role of 3D force networks in linking grain scale to macroscale processes in sheared granular debris

NASA Astrophysics Data System (ADS)

Mair, K.; Jettestuen, E.; Abe, S.

2013-12-01

Active faults, landslides and subglacial tills contain accumulations of granular debris that evolve during sliding. The macroscopic motion in these environments is at least to some extent determined by processes operating in this sheared granular material. A valid question is how the local behavior at the individual granular contacts actually sums up to influence macroscopic sliding. Laboratory experiments and numerical modeling can potentially help elucidate this. Observations of jamming (stick) and unjamming (flow) as well as concentrated shear bands on the scale of 5-10 grains suggest that a simple continuum description may be insufficient to capture important elements of the behavior. We therefore seek a measure of the organization of the granular fabric and the 3D structure of the load bearing skeleton that effectively demonstrates how the individual grain interactions are manifested in the macroscopic sliding behavior we observe. Contact force networks are an expression of this. Here we investigate the structure and variability of the most connected system spanning force networks produced in 3D discrete element models of granular layers under shear. We use percolation measures to identify, characterize, compare and track the evolution of these strongly connected contact force networks. We show that specific topological measures used in describing the networks, such as number of contacts and coordination number, are sensitive to grain size distribution (and likely the grain shape) of the material as well as loading conditions. Hence, faults of different maturity would be expected to accommodate shear in different ways. Distinct changes in the topological characteristics i.e. the geometry of strong force networks with accumulated strain are directly correlated to fluctuations in macroscopic shearing resistance. This suggests that 3D force networks play an important bridging role between individual grain scale processes and macroscopic sliding behavior.

Localization of the Norrie disease gene mRNA by in situ hybridization.

PubMed

Hartzer, M K; Cheng, M; Liu, X; Shastry, B S

1999-07-15

Norrie disease is a rare X-linked recessive neurodevelopmental disorder. The affected males manifest congenital blindness, which is often associated with hearing loss, mental retardation and psychiatric problems. Genetic linkage studies have localized the gene to the short arm of the X-chromosome and the gene has been isolated recently. The encoded protein is a member of the superfamily of growth factors containing a cystine knot motif and may be involved in cell adhesion and neurodevelopment. Molecular genetic analysis revealed a large number of missense, nonsense, deletion, and splice-site mutations among Norrie patients. In order to further determine the role of the Norrie disease gene, we studied the distribution pattern of its mRNA in the retina and in brain by in situ hybridization. The results show abundant hybridization signals in outer nuclear, inner nuclear, and ganglion cell layers of the retina in all three species (mice, rabbit, and human) examined. There was no significant expression in the vitreous body, lens, and rod outer segment. High expression levels were also observed in the cerebellar granular layer, hippocampus, olfactory bulb, cortex, and epithelium of the rabbit brain. These data suggest that the Norrie disease gene could play a critical role in the differentiation or maintenance of the differentiated state of the retina.

Side Effects of Neem Oil on the Midgut Endocrine Cells of the Green Lacewing Ceraeochrysa claveri (Navás) (Neuroptera: Chrysopidae).

PubMed

Scudeler, E L; Santos, D C

2014-04-01

We described the ultrastructure of Ceraeochrysa claveri (Navás) midgut endocrine cells in larva, pupa, and adult, and evaluated the side effects of ingested neem oil, a botanical insecticide obtained from the seeds of the neem tree (Azadirachta indica), on these cells. During the larval period, C. claveri were fed (ad libitum) Diatraea saccharalis (F.) eggs treated with neem oil at concentrations of 0.5%, 1%, or 2%. Transmission electron microscopy showed that two subtypes of endocrine cells, namely granular and vesicular, occurred in the midgut epithelium during the three stages of the life cycle. Both cell types did not reach the midgut lumen and were positioned basally in the epithelium. The endocrine cells did not show extensive infoldings of the basal plasma membrane, and there were numerous secretory granules in the basal region of the cytoplasm. In the granular endocrine cells, the granules were completely filled with a dense matrix. In the vesicular endocrine cells, the main secretory products consisted of haloed vesicles. Ultrastructural examination indicated that only the granular endocrine cells exhibited signs of morphologic changes of cell injury present in all life cycle stages after the larvae were chronically exposed to neem oil by ingestion. The major cellular damage consisted of dilatation and vesiculation of the rough endoplasmic reticulum and the development of smooth endoplasmic reticulum and mitochondrial swelling. Our data suggest that cytotoxic effects on midgut endocrine cells can contribute to a generalized disruption of the physiological processes in this organ due to a general alteration of endocrine function.

Fipronil mobility and transformation in undisturbed soil columns.

PubMed

Chatterjee, Niladri Sekhar; Gupta, Suman

2010-08-01

The downward movement of fipronil and its two toxic metabolites i.e. sulfone and desulfinyl were studied in undisturbed soil columns. Mobility behavior of two different formulations of fipronil viz granular and suspension concentrate were also studied. The undisturbed columns containing sandy loam soil were leached with water equivalent to 400 mm rainfall. Results revealed that although majority of the fipronil (approximately 80%) remained in top 0-5 cm layer, substantial amount (approximately 15%) moved to 5-10 cm depth. In case of metabolites sulfone and desulfinyl >90% of the residues remained in 0-5 cm core indicating low mobility of these metabolites in comparison to fipronil. Results of mobility behavior of fipronil in granular and SC formulations revealed low mobility in granular formulation. Sulfide was detected as the major degradation product in both the formulations and was found to be distributed throughout the column. A little amount of sulfone (0.1% of the total recovered) was also detected upto 10 cm depth.

Multifocal Adenomatous Oncocytic Hyperplasia of the Parotid Gland

PubMed Central

Kinoshita, Yuichi; Harada, Hiroshi; Kobayashi, Tadao K.; Yoshizawa, Katsuhiko; Yuri, Takashi; Takasu, Kosho; Tsubura, Airo; Shikata, Nobuaki

2014-01-01

Multifocal adenomatous oncocytic hyperplasia (MAOH) is a non-neoplastic lesion that is classified as oncocytosis. MAOH is a rare entity of the parotid gland and accounts for approximately 0.1% of salivary gland lesions. Here, we report a case of MAOH of the parotid gland. The patient was a 71-year-old woman who presented with discomfort at the left side of her neck. Fine-needle aspiration cytology of the parotid gland revealed a loose sheet-like cluster of round to polygonal cells with granular cytoplasm against a hemorrhagic background. The cells had round to oval, centrally located nuclei with granular chromatin and without distinct nucleoli. Histologically, the lesion was formed of many variable-sized nodules, comprising oncocyte-like cells with small round nuclei and eosinophilic granular cytoplasm that was positive for mitochondrial antibodies. The diagnosis of MAOH is difficult to make by cytology alone, because the findings overlap with those of other oncocytic lesions. In particular, the cytological findings of MAOH have not been sufficiently reported to date. A correlation of cytology and histology was expected. PMID:25580104

Immunohistochemical assessment of ATG7, LC3, and p62 in ameloblastomas.

PubMed

Okada, Miwa; Oikawa, Mariko; Miki, Yasuhiro; Shimizu, Yoshinaka; Echigo, Seishi; Takahashi, Tetsu; Kumamoto, Hiroyuki

2014-09-01

To investigate the roles of autophagy in tumorigenesis, cytodifferentiation, and prognosis of odontogenic tumors, we analyzed the immunohistochemical expression of ATG7, LC3, and p62 in odontogenic tissues. Tissue specimens of nine dental follicles and 69 ameloblastomas were immunohistochemically examined with antibodies against ATG7, LC3, and p62. Immunohistochemical reactivity for ATG7, LC3, and p62 was detected in many odontogenic epithelial cells and several endothelial cells and fibroblasts in dental follicles and ameloblastomas. ATG7 reactivity in ameloblatomas was significantly higher than that in dental follicles. Expression of ATG7, LC3, and p62 was found markedly in neoplastic cells near the basement membrane rather than central polyhedral cells in ameloblastomas. Reactivity for these molecules was significantly higher in unicystic ameloblastomas than in solid ameloblastomas. Granular cells in granular cell ameloblastomas showed obvious reactivity for the autophagy- related molecules, and LC3 reactivity in granular cell ameloblastomas was significantly higher than in other ameloblastoma variations. Recurrent ameloblastomas showed significantly lower reactivity of LC3 and p62 than primary ameloblastomas. Expression of ATG7, LC3, and p62 in dental follicles and ameloblastomas suggests that autophagy regulation might be affected by microenvironment alterations during tumorigenesis. The molecular machinery for autophagy is possibly involved in tissue architecture, neoplastic cell differentiation, and prognosis of the benign epithelial odontogenic tumor. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Energy metabolism of synaptosomes from different neuronal systems of rat cerebellum during aging: a functional proteomic characterization.

PubMed

Ferrari, Federica; Gorini, Antonella; Villa, Roberto Federico

2015-01-01

Functional proteomics was used to characterize age-related changes in energy metabolism of different neuronal pathways within the cerebellar cortex of Wistar rats aged 2, 6, 12, 18, and 24 months. The "large" synaptosomes, derived from the glutamatergic mossy fibre endings which make synaptic contact with the granule cells of the granular layer, and the "small" synaptosomes, derived from the pre-synaptic terminals of granule cells making synaptic contact with the dendrites of Purkinje cells, were isolated by a combined differential/gradient centrifugation technique. Because most brain disorders are associated with bioenergetic changes, the maximum rate (Vmax) of selected enzymes of glycolysis, Krebs' cycle, glutamate and amino acids metabolism, and acetylcholine catabolism were evaluated. The results show that "large" and "small" synaptosomes possess specific and independent metabolic features. This study represents a reliable model to study in vivo (1) the physiopathological molecular mechanisms of some brain diseases dependent on energy metabolism, (2) the responsiveness to noxious stimuli, and (3) the effects of drugs, discriminating their action sites at subcellular level on specific neuronal pathways.

Proton-conducting Micro-solid Oxide Fuel Cells with Improved Cathode Reactions by a Nanoscale Thin Film Gadolinium-doped Ceria Interlayer

PubMed Central

Li, Yong; Wang, Shijie; Su, Pei-Chen

2016-01-01

An 8 nm-thick gadolinium-doped ceria (GDC) layer was inserted as a cathodic interlayer between the nanoscale proton-conducting yttrium-doped barium zirconate (BZY) electrolyte and the porous platinum cathode of a micro-solid oxide fuel cell (μ-SOFC), which has effectively improved the cathode reaction kinetics and rendered high cell power density. The addition of the GDC interlayer significantly reduced the cathodic activation loss and increased the peak power density of the μ-SOFC by 33% at 400 °C. The peak power density reached 445 mW/cm2 at 425 °C, which is the highest among the reported μ-SOFCs using proton-conducting electrolytes. The impressive performance was attributed to the mixed protonic and oxygen ionic conducting properties of the nano-granular GDC, and also to the high densities of grain boundaries and lattice defects in GDC interlayer that favored the oxygen incorporation and transportation during the oxygen reduction reaction (ORR) and the water evolution reaction at cathode. PMID:26928192

The diffuse nervous network of Camillo Golgi: facts and fiction.

PubMed

Raviola, Elio; Mazzarello, Paolo

2011-01-07

The name of Camillo Golgi is inextricably associated, in the mind of most neuroscientists, with the theory that nerve cells communicate with one another by means of an intricate network of anastomosing axonal branches contained in the neuropil intervening between cell bodies in the gray matter of the brain and spinal cord. Examination, however, of Golgi's drawings in the papers published in the decade intervening between publication of his method (1873) and the beginning of his studies on malaria (1885) shows that axonal arborization in the cerebellar cortex and olfactory bulb are depicted as independent of one other. This is in striking contrast with the drawings included by Golgi in his 1906 Nobel lecture where the entire granular layer of the cerebellar cortex is occupied by a network of branching and anastomosing nerve processes. Thus, Golgi in his original papers on the cerebellum represents nerve cells as discrete units and only later in life merges axonal arborizations in the context of a lecture in defense of the reticular theory. Copyright © 2010 Elsevier B.V. All rights reserved.

Beyond Columnar Organization: Cell Type- and Target Layer-Specific Principles of Horizontal Axon Projection Patterns in Rat Vibrissal Cortex

PubMed Central

Narayanan, Rajeevan T.; Egger, Robert; Johnson, Andrew S.; Mansvelder, Huibert D.; Sakmann, Bert; de Kock, Christiaan P.J.; Oberlaender, Marcel

2015-01-01

Vertical thalamocortical afferents give rise to the elementary functional units of sensory cortex, cortical columns. Principles that underlie communication between columns remain however unknown. Here we unravel these by reconstructing in vivo-labeled neurons from all excitatory cell types in the vibrissal part of rat primary somatosensory cortex (vS1). Integrating the morphologies into an exact 3D model of vS1 revealed that the majority of intracortical (IC) axons project far beyond the borders of the principal column. We defined the corresponding innervation volume as the IC-unit. Deconstructing this structural cortical unit into its cell type-specific components, we found asymmetric projections that innervate columns of either the same whisker row or arc, and which subdivide vS1 into 2 orthogonal [supra-]granular and infragranular strata. We show that such organization could be most effective for encoding multi whisker inputs. Communication between columns is thus organized by multiple highly specific horizontal projection patterns, rendering IC-units as the primary structural entities for processing complex sensory stimuli. PMID:25838038

Embedded DCT and wavelet methods for fine granular scalable video: analysis and comparison

NASA Astrophysics Data System (ADS)

van der Schaar-Mitrea, Mihaela; Chen, Yingwei; Radha, Hayder

2000-04-01

Video transmission over bandwidth-varying networks is becoming increasingly important due to emerging applications such as streaming of video over the Internet. The fundamental obstacle in designing such systems resides in the varying characteristics of the Internet (i.e. bandwidth variations and packet-loss patterns). In MPEG-4, a new SNR scalability scheme, called Fine-Granular-Scalability (FGS), is currently under standardization, which is able to adapt in real-time (i.e. at transmission time) to Internet bandwidth variations. The FGS framework consists of a non-scalable motion-predicted base-layer and an intra-coded fine-granular scalable enhancement layer. For example, the base layer can be coded using a DCT-based MPEG-4 compliant, highly efficient video compression scheme. Subsequently, the difference between the original and decoded base-layer is computed, and the resulting FGS-residual signal is intra-frame coded with an embedded scalable coder. In order to achieve high coding efficiency when compressing the FGS enhancement layer, it is crucial to analyze the nature and characteristics of residual signals common to the SNR scalability framework (including FGS). In this paper, we present a thorough analysis of SNR residual signals by evaluating its statistical properties, compaction efficiency and frequency characteristics. The signal analysis revealed that the energy compaction of the DCT and wavelet transforms is limited and the frequency characteristic of SNR residual signals decay rather slowly. Moreover, the blockiness artifacts of the low bit-rate coded base-layer result in artificial high frequencies in the residual signal. Subsequently, a variety of wavelet and embedded DCT coding techniques applicable to the FGS framework are evaluated and their results are interpreted based on the identified signal properties. As expected from the theoretical signal analysis, the rate-distortion performances of the embedded wavelet and DCT-based coders are very similar. However, improved results can be obtained for the wavelet coder by deblocking the base- layer prior to the FGS residual computation. Based on the theoretical analysis and our measurements, we can conclude that for an optimal complexity versus coding-efficiency trade- off, only limited wavelet decomposition (e.g. 2 stages) needs to be performed for the FGS-residual signal. Also, it was observed that the good rate-distortion performance of a coding technique for a certain image type (e.g. natural still-images) does not necessarily translate into similarly good performance for signals with different visual characteristics and statistical properties.

Bone marrow mesenchymal stem cells accelerate the hyperglycemic refractory wound healing by inhibiting an excessive inflammatory response.

PubMed

Nan, Wenbin; Xu, Zhihao; Chen, Zhibin; Yuan, Xin; Lin, Juntang; Feng, Huigen; Lian, Jie; Chen, Hongli

2017-05-01

The aim of the present study was to evaluate the healing effect of bone marrow-derived mesenchymal stem cells administered to hyperglycemia model mice with skin wounds, and to explore the underlying mechanism contributing to their effects in promoting refractory wound healing. A full‑thickness skin wound mouse model was established, and refers to a wound of the skin and subcutaneous tissue. The mice were randomly divided into three groups: Blank control group, hyperglycemic group and a hyperglycemic group treated with stem cells. Wound healing was monitored and the wound‑healing rate was determined at 3, 6, 9, and 12 days following trauma. The structure of the organization of new skin tissue was observed by hematoxylin and eosin staining, and expression levels of the inflammatory cytokines interleukin (IL)‑6 and tumor necrosis factor (TNF)‑α were determined from 1 to 6 days following trauma. The wound healing of the hyperglycemic group was slower than that of the blank group, and the hyperglycemic mice treated with stem cells presented faster healing than the hyperglycemia group. The horny layer and granular layer of the skin were thinner and incomplete in the new skin tissue of the hyperglycemic group, whereas the new skin wound tissue basal layer was flat and demonstrated better fusion with the wound edge in the other two groups. The expression of inflammatory cytokines (IL‑6 and TNF‑α) was significantly increased in all three groups, with continuously higher expression in the hyperglycemic group and decreased expression in the other two groups over time. Hyperglycemia refractory wounds are likely related to the excessive expression of inflammatory cytokines surrounding the wound area. Stem cells may be able to alleviate the excessive inflammatory reaction in the wound tissue of hyperglycemic mice, so as to promote wound healing.

The mechanics of active matter: Broken-symmetry hydrodynamics of motile particles and granular layers

NASA Astrophysics Data System (ADS)

Ramaswamy, Sriram; Simha, R. Aditi

2006-09-01

This articles reviews briefly our recent theoretical results on order, fluctuations and flow in collections of self-driven particles, in suspension or on a solid surface. The theoretical approach we have developed applies not only to collections of organisms such as schools of fish or collectively swimming bacteria, but also to motor-microtubule extracts with ATP and, most surprisingly, to agitated monolayers of orientable granular particles. We contrast the behaviour of these active systems with that of thermal equilibrium systems with the same symmetry. As an illustration of the role of activity we show that active smectics in three dimensions show true long-range order, unlike their thermal equilibrium counterparts.

PRODUCTION OF SHEET FROM PARTICULATE MATERIAL

DOEpatents

Blainey, A.

1959-05-12

A process is presented for forming coherent sheet material from particulate material such as granular or powdered metal, granular or powdered oxide, slurries, pastes, and plastic mixes which cohere under pressure. The primary object is to avoid the use of expensive and/ or short lived pressing tools, that is, dies and specially profiled rolls, and so to reduce the cost of the product and to prcvide in a simple manner for the making of the product in a variety of shapes or sizes. The sheet material is formed when the particulate material is laterally confined in a boundary material deformable in all lateral directions under axial pressure and then axially compressing the layer of particulate material together with the boundary material.

Reconfiguration of a flexible fiber immersed in a 2D dense granular flow close to the jamming transition

NASA Astrophysics Data System (ADS)

Kolb, Evelyne; Algarra, Nicolas; Vandembroucq, Damien; Lazarus, Arnaud

2015-11-01

We propose a new fluid/structure interaction in the unusual case of a dense granular medium flowing against an elastic fibre acting as a flexible intruder. We experimentally studied the deflection of a mylar flexible beam clamped at one side, the other free side facing a 2D granular flow in a horizontal cell moving at a constant velocity. We investigated the reconfiguration of the fibre as a function of the fibre's rigidity and of the granular packing fraction close but below the jamming in 2D. Imposing the fibre geometry like its length or thickness sets the critical buckling force the fibre is able to resist if it was not supported by lateral grains, while increasing the granular packing fraction might laterally consolidate the fibre and prevent it from buckling. But on the other side, the approach to jamming transition by increasing the granular packing fraction will be characterized by a dramatically increasing size of the cluster of connected grains forming a solid block acting against the fibre, which might promote the fibre's deflection. Thus, we investigated the granular flow fields, the fibre's deflexion as well as the forces experienced by the fibre and compared them with theoretical predictions from elastica for different loadings along the fibre. PMMH, CNRS UMR 7636, UPMC, ESPCI-ParisTech, 10 rue Vauquelin, 75231 Paris Cedex 05, France.

Reevaluation of the Beam and Radial Hypotheses of Parallel Fiber Action in the Cerebellar Cortex

PubMed Central

Cramer, Samuel W.; Gao, Wangcai; Chen, Gang

2013-01-01

The role of parallel fibers (PFs) in cerebellar physiology remains controversial. Early studies inspired the “beam” hypothesis whereby granule cell (GC) activation results in PF-driven, postsynaptic excitation of beams of Purkinje cells (PCs). However, the “radial” hypothesis postulates that the ascending limb of the GC axon provides the dominant input to PCs and generates patch-like responses. Using optical imaging and single-cell recordings in the mouse cerebellar cortex in vivo, this study reexamines the beam versus radial controversy. Electrical stimulation of mossy fibers (MFs) as well as microinjection of NMDA in the granular layer generates beam-like responses with a centrally located patch-like response. Remarkably, ipsilateral forepaw stimulation evokes a beam-like response in Crus I. Discrete molecular layer lesions demonstrate that PFs contribute to the peripherally generated responses in Crus I. In contrast, vibrissal stimulation induces patch-like activation of Crus II and GABAA antagonists fail to convert this patch-like activity into a beam-like response, implying that molecular layer inhibition does not prevent beam-like responses. However, blocking excitatory amino acid transporters (EAATs) generates beam-like responses in Crus II. These beam-like responses are suppressed by focal inhibition of MF-GC synaptic transmission. Using EAAT4 reporter transgenic mice, we show that peripherally evoked patch-like responses in Crus II are aligned between parasagittal bands of EAAT4. This is the first study to demonstrate beam-like responses in the cerebellar cortex to peripheral, MF, and GC stimulation in vivo. Furthermore, the spatial pattern of the responses depends on extracellular glutamate and its local regulation by EAATs. PMID:23843513

Assessment of β-carotene content, cell physiology and morphology of the yellow yeast Rhodotorula glutinis mutant 400A15 using flow cytometry.

PubMed

Cutzu, Raffaela; Clemente, Ana; Reis, Alberto; Nobre, Beatriz; Mannazzu, Ilaria; Roseiro, José; Lopes da Silva, Teresa

2013-08-01

Flow cytometry was used to assess β-carotene content, cell membrane permeability, cell size and granularity in Rhodotorula glutinis mutant 400A15 grown under different oxygen transfer coefficients (k L a) and carbon to nitrogen ratios (C/N). A Doehlert distribution was used in order to select the best conditions that induced the highest carotenoids production. The highest β-carotene content (0.79 mg g(-1) DCW) at the lowest k L a and C/N (5 × 10(-3) s(-1) and 11.3 respectively). Under these conditions, the biomass concentration attained 18.60 g L(-1). The highest ratio of cells with permeabilised membranes (2.6 %), and the highest cell size and granularity were also obtained under these conditions. It was observed that C/N showed a stronger influence than the k L a on the measured cell parameters.

Biophysics Model of Heavy-Ion Degradation of Neuron Morphology in Mouse Hippocampal Granular Cell Layer Neurons.

PubMed

Alp, Murat; Cucinotta, Francis A

2018-03-01

Exposure to heavy-ion radiation during cancer treatment or space travel may cause cognitive detriments that have been associated with changes in neuron morphology and plasticity. Observations in mice of reduced neuronal dendritic complexity have revealed a dependence on radiation quality and absorbed dose, suggesting that microscopic energy deposition plays an important role. In this work we used morphological data for mouse dentate granular cell layer (GCL) neurons and a stochastic model of particle track structure and microscopic energy deposition (ED) to develop a predictive model of high-charge and energy (HZE) particle-induced morphological changes to the complex structures of dendritic arbors. We represented dendrites as cylindrical segments of varying diameter with unit aspect ratios, and developed a fast sampling method to consider the stochastic distribution of ED by δ rays (secondary electrons) around the path of heavy ions, to reduce computational times. We introduce probabilistic models with a small number of parameters to describe the induction of precursor lesions that precede dendritic snipping, denoted as snip sites. Predictions for oxygen ( 16 O, 600 MeV/n) and titanium ( 48 Ti, 600 MeV/n) particles with LET of 16.3 and 129 keV/μm, respectively, are considered. Morphometric parameters to quantify changes in neuron morphology are described, including reduction in total dendritic length, number of branch points and branch numbers. Sholl analysis is applied for single neurons to elucidate dose-dependent reductions in dendritic complexity. We predict important differences in measurements from imaging of tissues from brain slices with single neuron cell observations due to the role of neuron death through both soma apoptosis and excessive dendritic length reduction. To further elucidate the role of track structure, random segment excision (snips) models are introduced and a sensitivity study of the effects of the modes of neuron death in predictions of morphometric parameters is described. An important conclusion of this study is that δ rays play a major role in neuron morphological changes due to the large spatial distribution of damage sites, which results in a reduced dependence on LET, including modest difference between 16 O and 48 Ti, compared to damages resulting from ED in localized damage sites.

Scaffolding proteins in the development and maintenance of the epidermal permeability barrier.

PubMed

Crawford, Melissa; Dagnino, Lina

2017-10-02

The skin of mammals and other terrestrial vertebrates protects the organism against the external environment, preventing heat, water and electrolyte loss, as well as entry of chemicals and pathogens. Impairments in the epidermal permeability barrier function are associated with the genesis and/or progression of a variety of pathological conditions, including genetic inflammatory diseases, microbial and viral infections, and photodamage induced by UV radiation. In mammals, the outside-in epidermal permeability barrier is provided by the joint action of the outermost cornified layer, together with assembled tight junctions in granular keratinocytes found in the layers underneath. Tight junctions serve as both outside-in and inside-out barriers, and impede paracellular movements of ions, water, macromolecules and microorganisms. At the molecular level, tight junctions consist of integral membrane proteins that form an extracellular seal between adjacent cells, and associate with cytoplasmic scaffold proteins that serve as links with the actin cytoskeleton. In this review, we address the roles that scaffold proteins play specifically in the establishment and maintenance of the epidermal permeability barrier, and how various pathologies alter or impair their functions.

VGLUT2 mRNA and protein expression in the visual thalamus and midbrain of prosimian galagos (Otolemur garnetti).

PubMed

Balaram, Pooja; Takahata, Toru; Kaas, Jon H

2011-03-01

Vesicular glutamate transporters (VGLUTs) control the storage and presynaptic release of glutamate in the central nervous system, and are involved in the majority of glutamatergic transmission in the brain. Two VGLUT isoforms, VGLUT1 and VGLUT2, are known to characterize complementary distributions of glutamatergic neurons in the rodent brain, which suggests that they are each responsible for unique circuits of excitatory transmission. In rodents, VGLUT2 is primarily utilized in thalamocortical circuits, and is strongly expressed in the primary sensory nuclei, including all areas of the visual thalamus. The distribution of VGLUT2 in the visual thalamus and midbrain has yet to be characterized in primate species. Thus, the present study describes the expression of VGLUT2 mRNA and protein across the visual thalamus and superior colliculus of prosimian galagos to provide a better understanding of glutamatergic transmission in the primate brain. VGLUT2 is strongly expressed in all six layers of the dorsal lateral geniculate nucleus, and much less so in the intralaminar zones, which correspond to retinal and superior collicular inputs, respectively. The parvocellular and magnocellular layers expressed VGLUT2 mRNA more densely than the koniocellular layers. A patchy distribution of VGLUT2 positive terminals in the pulvinar complex possibly reflects inputs from the superior colliculus. The upper superficial granular layers of the superior colliculus, with inputs from the retina, most densely expressed VGLUT2 protein, while the lower superficial granular layers, with projections to the pulvinar, most densely expressed VGLUT2 mRNA. The results are consistent with the conclusion that retinal and superior colliculus projections to the thalamus depend highly on the VGLUT2 transporter, as do cortical projections from the magnocellular and parvocellular layers of the lateral geniculate nucleus and neurons of the pulvinar complex.

A circadian clock in the olfactory bulb anticipates feeding during food anticipatory activity.

PubMed

Nolasco, Nahum; Juárez, Claudia; Morgado, Elvira; Meza, Enrique; Caba, Mario

2012-01-01

Rabbit pups ingest food, in this case milk, once a day with circadian periodicity and are a natural model of food anticipatory activity. During nursing, several sensory systems receive information about properties of the food, one of them being the olfactory system, which has received little attention in relation to synchronization by food. In addition, the olfactory bulb has a circadian pacemaker that exhibits rhythms independently of the suprachiasmatic nucleus, but the biological functions of these rhythms are largely unknown. In the present contribution, we hypothesized that circadian suckling of milk synchronizes rhythms in the olfactory bulb. To this aim we explored by immunohistochemistry, rhythms of FOS and PER1 proteins, as indicators of activation and reporter of oscillations, respectively, through a complete 24-h cycle in periglomerular, mitral and granular cell layers of both the main and the accessory olfactory bulb. Subjects were 7-day-old rabbit pups scheduled to nurse during the night (02:00 h) or day (10:00 h), and also fasted subjects, to explore the possible persistence of oscillations. In the three layers of the main olfactory bulb, FOS was high at time of nursing, then further increased 1.5 h afterward, and then decreased to increase again in advance of the next nursing bout. This pattern persisted, without the postprandial increase, in fasted subjects with a shift in subjects nursed at 02:00. PER1 was increased 2-8 h after nursing and this increase persisted in most cell layers, with a shift, in fasted subjects. In the accessory olfactory bulb we only observed a consistent pattern of FOS expression in the mitral cell layer of nursed subjects, similar to that of the main olfactory bulb. We conclude that the main olfactory bulb is synchronized during milk ingestion, but during fasting its oscillations perhaps are modulated by the suprachiasmatic nucleus, as proposed for rodents.

A dilation-driven vortex flow in sheared granular materials explains a rheometric anomaly.

PubMed

Krishnaraj, K P; Nott, Prabhu R

2016-02-11

Granular flows occur widely in nature and industry, yet a continuum description that captures their important features is yet not at hand. Recent experiments on granular materials sheared in a cylindrical Couette device revealed a puzzling anomaly, wherein all components of the stress rise nearly exponentially with depth. Here we show, using particle dynamics simulations and imaging experiments, that the stress anomaly arises from a remarkable vortex flow. For the entire range of fill heights explored, we observe a single toroidal vortex that spans the entire Couette cell and whose sense is opposite to the uppermost Taylor vortex in a fluid. We show that the vortex is driven by a combination of shear-induced dilation, a phenomenon that has no analogue in fluids, and gravity flow. Dilatancy is an important feature of granular mechanics, but not adequately incorporated in existing models.

Giant ripples on comet 67P/Churyumov–Gerasimenko sculpted by sunset thermal wind

PubMed Central

Jia, Pan; Andreotti, Bruno; Claudin, Philippe

2017-01-01

Explaining the unexpected presence of dune-like patterns at the surface of the comet 67P/Churyumov–Gerasimenko requires conceptual and quantitative advances in the understanding of surface and outgassing processes. We show here that vapor flow emitted by the comet around its perihelion spreads laterally in a surface layer, due to the strong pressure difference between zones illuminated by sunlight and those in shadow. For such thermal winds to be dense enough to transport grains—10 times greater than previous estimates—outgassing must take place through a surface porous granular layer, and that layer must be composed of grains whose roughness lowers cohesion consistently with contact mechanics. The linear stability analysis of the problem, entirely tested against laboratory experiments, quantitatively predicts the emergence of bedforms in the observed wavelength range and their propagation at the scale of a comet revolution. Although generated by a rarefied atmosphere, they are paradoxically analogous to ripples emerging on granular beds submitted to viscous shear flows. This quantitative agreement shows that our understanding of the coupling between hydrodynamics and sediment transport is able to account for bedform emergence in extreme conditions and provides a reliable tool to predict the erosion and accretion processes controlling the evolution of small solar system bodies. PMID:28223535

Thickness-, Composition-, and Magnetic-Field-Dependent Complex Impedance Spectroscopy of Granular-Type-Barrier Co/Co-Al2O3/Co MTJs

NASA Astrophysics Data System (ADS)

Tuan, Nguyen Anh; Anh, Nguyen Tuan; Nga, Nguyen Tuyet; Tue, Nguyen Anh; Van Cuong, Giap

2016-06-01

The alternating-current (ac) electrical properties of granular-type-barrier magnetic tunnel junctions (GBMTJs) based on Co/Co x (Al2O3)1- x ( t)/Co trilayer structures have been studied using complex impedance spectroscopy (CIS). Their CIS characteristics were investigated in external magnetic fields varying from 0 kOe to 3 kOe as a function of Co composition x at 10 at.%, 25 at.%, and 35 at.%, with barrier layer thickness t of 20 nm to 90 nm. The influence of these factors on the behaviors of the ac impedance response of the GBMTJs was deeply investigated and attributed to the dielectric or conducting nature of the Co-Al2O3 barrier layer. The most remarkable typical phenomena observed in these behaviors, even appearing paradoxical, include lower impedance for thicker t for each given x, a declining trend of Z with increasing x, a clear decrease of Z with H, and especially a partition of Z into zones according to the H value. All these effects are analyzed and discussed to demonstrate that diffusion-type and mass-transfer-type phenomena can be inferred from processes such as spin tunneling and Coulomb or spin blockade in the Co-Al2O3 barrier layer.

Biofilm reactors for industrial bioconversion processes: employing potential of enhanced reaction rates

PubMed Central

Qureshi, Nasib; Annous, Bassam A; Ezeji, Thaddeus C; Karcher, Patrick; Maddox, Ian S

2005-01-01

This article describes the use of biofilm reactors for the production of various chemicals by fermentation and wastewater treatment. Biofilm formation is a natural process where microbial cells attach to the support (adsorbent) or form flocs/aggregates (also called granules) without use of chemicals and form thick layers of cells known as "biofilms." As a result of biofilm formation, cell densities in the reactor increase and cell concentrations as high as 74 gL-1 can be achieved. The reactor configurations can be as simple as a batch reactor, continuous stirred tank reactor (CSTR), packed bed reactor (PBR), fluidized bed reactor (FBR), airlift reactor (ALR), upflow anaerobic sludge blanket (UASB) reactor, or any other suitable configuration. In UASB granular biofilm particles are used. This article demonstrates that reactor productivities in these reactors have been superior to any other reactor types. This article describes production of ethanol, butanol, lactic acid, acetic acid/vinegar, succinic acid, and fumaric acid in addition to wastewater treatment in the biofilm reactors. As the title suggests, biofilm reactors have high potential to be employed in biotechnology/bioconversion industry for viable economic reasons. In this article, various reactor types have been compared for the above bioconversion processes. PMID:16122390

Changes in cell proliferation kinetics in the mouse cerebellum after total asphyxia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yoshioka, H.; Mino, M.; Morikawa, Y.

1985-12-01

This study was undertaken to investigate the effects of neonatal asphyxia on brain development, with special reference to the kinetics of neuronal proliferation by using autoradiography. For 30 minutes, two-day-old suckling mice, Jcl:ICR strain, were put into a chamber which was constantly flushed with 100% CO/sub 2/ gas. After the exposure to asphyxia, 29% of the mice survived. Cell cycle studies were carried out at two days and at seven days on the external matrix cells, the precursor of the granule cells, at the external granular layer of the cerebellum from CO/sub 2/-exposed and control mice by /sup 3/H-thymidine autoradiography.more » At two days the generation time of the control mice was about 15 hours, whereas that of the asphyxiated mice was about 17 hours. The prolongation of the generation time in the asphyxiated mice was caused mainly by a delay in the G2 phase. This prolongation was apparent for about five days and thereafter growth caught up. These results suggest that neonatal asphyxia has an adverse effect on cerebellar neuronal proliferation that may revert to normal spontaneously in older animals.« less

Neuropilin 2 Signaling Is Involved in Cell Positioning of Adult-born Neurons through Glycogen Synthase Kinase-3β (GSK3β).

PubMed

Ng, Teclise; Hor, Catherine H H; Chew, Benjamin; Zhao, Jing; Zhong, Zhong; Ryu, Jae Ryun; Goh, Eyleen L K

2016-11-25

Proper positioning of neurons is fundamental for brain functions. However, little is known on how adult-born neurons generated in the hilar side of hippocampal dentate gyrus migrate into the granular cell layer. Because class 3 Semaphorins (Sema3) are involved in dendritic growth of these newborn neurons, we examined whether they are essential for cell positioning. We disrupted Sema3 signaling by silencing neuropilin 1 (NRP1) or 2 (NRP2), the main receptors for Sema3A and Sema3F, in neural progenitors of adult mouse dentate gyrus. Silencing of NRP2, but not NRP1, affected cell positioning of adult newborn neurons. Glycogen synthase kinase-3β (GSK3β) knockdown phenocopied this NRP2 silencing-mediated cell positioning defect, but did not affect dendritic growth. Furthermore, GSK3β is activated upon stimulation with Sema3F, and GSK3β overexpression rescued the cell positioning phenotypes seen in NRP2-deficient neurons. These results point to a new role for NRP2 in the positioning of neurons during adult hippocampal neurogenesis, acting via the GSK3β signaling pathway. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

A Theory of How Columns in the Neocortex Enable Learning the Structure of the World

PubMed Central

Hawkins, Jeff; Ahmad, Subutai; Cui, Yuwei

2017-01-01

Neocortical regions are organized into columns and layers. Connections between layers run mostly perpendicular to the surface suggesting a columnar functional organization. Some layers have long-range excitatory lateral connections suggesting interactions between columns. Similar patterns of connectivity exist in all regions but their exact role remain a mystery. In this paper, we propose a network model composed of columns and layers that performs robust object learning and recognition. Each column integrates its changing input over time to learn complete predictive models of observed objects. Excitatory lateral connections across columns allow the network to more rapidly infer objects based on the partial knowledge of adjacent columns. Because columns integrate input over time and space, the network learns models of complex objects that extend well beyond the receptive field of individual cells. Our network model introduces a new feature to cortical columns. We propose that a representation of location relative to the object being sensed is calculated within the sub-granular layers of each column. The location signal is provided as an input to the network, where it is combined with sensory data. Our model contains two layers and one or more columns. Simulations show that using Hebbian-like learning rules small single-column networks can learn to recognize hundreds of objects, with each object containing tens of features. Multi-column networks recognize objects with significantly fewer movements of the sensory receptors. Given the ubiquity of columnar and laminar connectivity patterns throughout the neocortex, we propose that columns and regions have more powerful recognition and modeling capabilities than previously assumed. PMID:29118696

A Spiking Neural Simulator Integrating Event-Driven and Time-Driven Computation Schemes Using Parallel CPU-GPU Co-Processing: A Case Study.

PubMed

Naveros, Francisco; Luque, Niceto R; Garrido, Jesús A; Carrillo, Richard R; Anguita, Mancia; Ros, Eduardo

2015-07-01

Time-driven simulation methods in traditional CPU architectures perform well and precisely when simulating small-scale spiking neural networks. Nevertheless, they still have drawbacks when simulating large-scale systems. Conversely, event-driven simulation methods in CPUs and time-driven simulation methods in graphic processing units (GPUs) can outperform CPU time-driven methods under certain conditions. With this performance improvement in mind, we have developed an event-and-time-driven spiking neural network simulator suitable for a hybrid CPU-GPU platform. Our neural simulator is able to efficiently simulate bio-inspired spiking neural networks consisting of different neural models, which can be distributed heterogeneously in both small layers and large layers or subsystems. For the sake of efficiency, the low-activity parts of the neural network can be simulated in CPU using event-driven methods while the high-activity subsystems can be simulated in either CPU (a few neurons) or GPU (thousands or millions of neurons) using time-driven methods. In this brief, we have undertaken a comparative study of these different simulation methods. For benchmarking the different simulation methods and platforms, we have used a cerebellar-inspired neural-network model consisting of a very dense granular layer and a Purkinje layer with a smaller number of cells (according to biological ratios). Thus, this cerebellar-like network includes a dense diverging neural layer (increasing the dimensionality of its internal representation and sparse coding) and a converging neural layer (integration) similar to many other biologically inspired and also artificial neural networks.

Jacalin and peanut agglutinin (PNA) bindings in the taste bud cells of the rat: new reliable markers for type IV cells of the rat taste buds.

PubMed

Taniguchi, Ryo; Shi, Lei; Fujii, Masae; Ueda, Katsura; Honma, Shiho; Wakisaka, Satoshi

2005-12-01

Lectin histochemistry of Jacalin (Artocarpus integrifolia) and peanut agglutinin (PNA), specific lectins for galactosyl (beta-1, 3) N-acetylgalactosamine (galactosyl (beta-1, 3) GalNAc), was applied to the gustatory epithelium of the adult rat. In the ordinary lingual epithelium, Jacalin and PNA labeled the cell membrane from the basal to granular cell layer. They also bound membranes of rounded-cells at the basal portion of taste buds, but the number of PNA labeled cells was smaller than that of Jacalin labeled cells. There was no apparent difference in the binding patterns of Jacalin and PNA among the taste buds of the lingual papillae and those of the palatal epithelium. Occasionally, a few spindle-shaped cells were labeled with Jacalin, but not with PNA. Double labeling of Jacalin and alpha-gustducin, a specific marker for type II cells, revealed that Jacalin-labeled spindle-shaped taste cells were immunonegative for alpha-gustducin. Spindle-shaped cells expressing protein gene product 9.5 (PGP 9.5) immunoreactivity lacked Jacalin labeling. During the development of taste buds in circumvallate papillae, the binding pattern of Jacalin became almost identical from postnatal day 5. The present results indicate that rounded cells at the basal portion of the taste buds cells (type IV cells) bind to Jacalin and PNA, and these lectins are specific markers for type IV cells of the rat taste cells.

Bonded-cell model for particle fracture.

PubMed

Nguyen, Duc-Hanh; Azéma, Emilien; Sornay, Philippe; Radjai, Farhang

2015-02-01

Particle degradation and fracture play an important role in natural granular flows and in many applications of granular materials. We analyze the fracture properties of two-dimensional disklike particles modeled as aggregates of rigid cells bonded along their sides by a cohesive Mohr-Coulomb law and simulated by the contact dynamics method. We show that the compressive strength scales with tensile strength between cells but depends also on the friction coefficient and a parameter describing cell shape distribution. The statistical scatter of compressive strength is well described by the Weibull distribution function with a shape parameter varying from 6 to 10 depending on cell shape distribution. We show that this distribution may be understood in terms of percolating critical intercellular contacts. We propose a random-walk model of critical contacts that leads to particle size dependence of the compressive strength in good agreement with our simulation data.

Tolbutamide stimulates exocytosis of glucagon by inhibition of a mitochondrial-like ATP-sensitive K+ (KATP) conductance in rat pancreatic A-cells

PubMed Central

Høy, Marianne; Olsen, Hervør L; Bokvist, Krister; Buschard, Karsten; Barg, Sebastian; Rorsman, Patrik; Gromada, Jesper

2000-01-01

Capacitance measurements were used to examine the effects of the sulphonylurea tolbutamide on Ca2+-dependent exocytosis in isolated glucagon-secreting rat pancreatic A-cells. When applied extracellularly, tolbutamide stimulated depolarization-evoked exocytosis 4.2-fold without affecting the whole-cell Ca2+ current. The concentration dependence of the stimulatory action was determined by intracellular application through the recording pipette. Tolbutamide produced a concentration-dependent increase in cell capacitance. Half-maximal stimulation was observed at 33 μm and the maximum stimulation corresponded to a 3.4-fold enhancement of exocytosis. The stimulatory action of tolbutamide was dependent on protein kinase C activity. The action of tolbutamide was mimicked by the general K+ channel blockers TEA (10 mm) and quinine (10 μm). A similar stimulation was elicited by 5-hydroxydecanoate (5-HD; 10 μm), an inhibitor of mitochondrial ATP-sensitive K+ (KATP) channels. Tolbutamide-stimulated, but not TEA-induced, exocytosis was antagonized by the K+ channel openers diazoxide, pinacidil and cromakalim. Dissipating the transgranular K+ gradient with nigericin and valinomycin inhibited tolbutamide- and Ca2+-evoked exocytosis. Furthermore, tolbutamide- and Ca2+-induced exocytosis were abolished by the H+ ionophore FCCP or by arresting the vacuolar (V-type) H+-ATPase with bafilomycin A1 or DCCD. Finally, ammonium chloride stimulated exocytosis to a similar extent to that obtained with tolbutamide. We propose that during granular maturation, a granular V-type H+-ATPase pumps H+ into the secretory granule leading to the generation of a pH gradient across the granular membrane and the development of a positive voltage inside the granules. The pumping of H+ is facilitated by the concomitant exit of K+ through granular K+ channels with pharmacological properties similar to those of mitochondrial KATP channels. Release of granules that have been primed is then facilitated by the addition of K+ channel blockers. The resulting increase in membrane potential promotes exocytosis by unknown mechanisms, possibly involving granular alkalinization. PMID:10944174

Installing Mechanics of Granular Materials (MGM) experiment Test Cell

NASA Technical Reports Server (NTRS)

1996-01-01

Astronaut Jay Apt installs Mechanics of Granular Materials (MGM0 test cell on STS-79. Sand and soil grains have faces that can cause friction as they roll and slide against each other, or even cause sticking and form small voids between grains. This complex behavior can cause soil to behave like a liquid under certain conditions such as earthquakes or when powders are handled in industrial processes. MGM experiments aboard the Space Shuttle use the microgravity of space to simulate this behavior under conditions that carnot be achieved in laboratory tests on Earth. MGM is shedding light on the behavior of fine-grain materials under low effective stresses. Applications include earthquake engineering, granular flow technologies (such as powder feed systems for pharmaceuticals and fertilizers), and terrestrial and planetary geology. Nine MGM specimens have flown on two Space Shuttle flights. Another three are scheduled to fly on STS-107. The principal investigator is Stein Sture of the University of Colorado at Boulder. (Credit: NASA/John Space Center).

Methods of parallel computation applied on granular simulations

NASA Astrophysics Data System (ADS)

Martins, Gustavo H. B.; Atman, Allbens P. F.

2017-06-01

Every year, parallel computing has becoming cheaper and more accessible. As consequence, applications were spreading over all research areas. Granular materials is a promising area for parallel computing. To prove this statement we study the impact of parallel computing in simulations of the BNE (Brazil Nut Effect). This property is due the remarkable arising of an intruder confined to a granular media when vertically shaken against gravity. By means of DEM (Discrete Element Methods) simulations, we study the code performance testing different methods to improve clock time. A comparison between serial and parallel algorithms, using OpenMP® is also shown. The best improvement was obtained by optimizing the function that find contacts using Verlet's cells.

Lesion-induced plasticity of high affinity choline uptake in the developing rat fascia dentata.

PubMed

Nadler, J V; Shelton, D L; Cotman, C W

1979-03-23

After removal of the perforant path input to the rat fascia dentata at the age of 11 days, cholinergic septohippocampal fibers invade the denervated area. We have examined the effect of this lesion on hemicholinium-sensitive, high affinity choline uptake and its coupling to acetylcholine synthesis, specific properties of the septohippocampal input. Removal of the ipsilateral perforant path fibers increased the velocity of high affinity choline uptake by dentate particulate preparations, usually within 1 day. Studies conducted 5--104 days after operation showed a consistent 50--65% elevation in the molecular (denervated) layer. In contrast, the choline uptake rate in the granular layer eventually decreased slightly. Calculation of choline uptake rates independently of protein (per whole region) revealed that fasciae dentatae from operated and control sides accumulated choline at approximately equal rates, but on the operated side a greater percentage was transported by structures from the molecular layer and a lesser percentage by those from the granular layer. The rate of acetylcholine synthesis from exogenous choline increased to the same extent as high affinity choline uptake from 3 days after operation onwards. The changes in high affinity choline uptake and acetylcholine synthesis coincided spatially and temporally with the reactive growth of septohippocampal fibers. Our results support the view that a perforant path lesion during development permanently alters the distribution of functional septohippocampal boutons in the fascia dentata. Acetylcholine synthesis is regulated to the same extent by high affinity choline uptake in the anomalous boutons as in normally located boutons.

Development of models to estimate the subgrade and subbase layers' resilient modulus from in-situ devices test results for construction control.

DOT National Transportation Integrated Search

2009-05-01

The primary objective of this research was to develop models that predict the resilient modulus of cohesive and granular soils from the test results of various in-situ test devices for possible application in QA/QC during construction of pavement str...

Spherical shock-wave propagation in three-dimensional granular packings.

PubMed

Xue, Kun; Bai, Chun-Hua

2011-02-01

We investigate numerically the spherical shock-wave propagation in an open dense granular packing perturbed by the sudden expansion of a spherical intruder in the interior of the pack, focusing on the correlation between geometrical fabrics and propagating properties. The measurements of the temporal and spatial variations in a variety of propagating properties define a consistent serrated wave substructure with characteristic length on the orders of particle diameters. Further inspection of particle packing reveals a well-defined particle layering that persists several particle diameters away from the intruder, although its dominant effects are only within one to two diameters. This interface-induced layering not only exactly coincides with the serrated wave profile, but also highlights the competition between two energy transmission mechanisms involving distinct transport speeds. The alternating dominances between these two mechanisms contribute to the nonlinear wave propagation on the particle scale. Moreover, the proliferation of intricate three-dimensional contact force networks suggests the anisotropic stress transmission, which is found to also arise from the localized packing structure in the vicinity of the intruder.

A spectral approach for the stability analysis of turbulent open-channel flows over granular beds

NASA Astrophysics Data System (ADS)

Camporeale, C.; Canuto, C.; Ridolfi, L.

2012-01-01

A novel Orr-Sommerfeld-like equation for gravity-driven turbulent open-channel flows over a granular erodible bed is here derived, and the linear stability analysis is developed. The whole spectrum of eigenvalues and eigenvectors of the complete generalized eigenvalue problem is computed and analyzed. The fourth-order eigenvalue problem presents singular non-polynomial coefficients with non-homogenous Robin-type boundary conditions that involve first and second derivatives. Furthermore, the Exner condition is imposed at an internal point. We propose a numerical discretization of spectral type based on a single-domain Galerkin scheme. In order to manage the presence of singular coefficients, some properties of Jacobi polynomials have been carefully blended with numerical integration of Gauss-Legendre type. The results show a positive agreement with the classical experimental data and allow one to relate the different types of instability to such parameters as the Froude number, wavenumber, and the roughness scale. The eigenfunctions allow two types of boundary layers to be distinguished, scaling, respectively, with the roughness height and the saltation layer for the bedload sediment transport.

Pathological effects of in utero methylmercury exposure on the cerebellum of the golden hamster: early effects upon the neonatal cerebellar cortex-Part I

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reuhl, K.R.; Chang, L.W.; Townsend, J.W.

1981-12-01

Pregnant golden hamsters (Mesocricetus auratus) were given either a single dose of 10 mg methylmercury/kg on gestational day 10 or daily doses of 2 mg/kg on gestational days 10-15. Cerebella of experimental and control offspring were examined by light and electron microscopy during the first month of postnatal life. Degenerative changes, characterized by accumulations of lysosomes and areas of floccular cytoplasmic degradation, were frequently observed in neuroblasts of the external granular layer (EGL) as well as in more differentiated neural elements in the molecular and internal granular layers. Pyknotic nuclei were seen singly and in groups throughout the EGL ofmore » treated animals. Developing dendrites appeared particularly sensitive to methylmercury. Affected dendrites were swollen and packed with degenerating cytoplasmic material. Astrocytes and perivascular macrophages also contained large aggregates of irregular electron-opague debris, lysosomes, and large lipid droplets. Pathological alterations in the cerebellum were most pronounced during the first 15 days of postpartum life.« less

Influence of deformation on dolomite rim growth kinetics

NASA Astrophysics Data System (ADS)

Helpa, Vanessa; Rybacki, Erik; Grafulha Morales, Luiz Fernando; Dresen, Georg

2015-04-01

Using a gas-deformation apparatus stacks of oriented calcite (CaCO3) and magnesite (MgCO3) single crystals were deformed at T = 750° C and P = 400 MPa to examine the influence of stress and strain on magnesio-calcite and dolomite (CaMg[CO3]2) growth kinetics. Triaxial compression and torsion tests performed at constant stresses between 7 and 38 MPa and test durations between 4 and 171 hours resulted in bulk strains of 0.03-0.2 and maximum shear strains of 0.8-5.6, respectively. The reaction rims consist of fine-grained (2-7 μm) dolomite with palisade-shaped grains growing into magnesite reactants and equiaxed granular dolomite grains next to calcite. In between dolomite and pure calcite, magnesio-calcite grains evolved with an average grain size of 20-40 μm. Grain boundaries tend to be straighter at high bulk strains and equilibrium angles at grain triple junctions are common within the magnesio-calcite layer. Transmission electron microscopy shows almost dislocation free palisades and increasing dislocation density within granular dolomite towards the magnesio-calcite boundary. Within magnesio-calcite grains, dislocations are concentrated at grain boundaries. Variation of time at fixed stress (˜17 MPa) yields a parabolic time dependence of dolomite rim width, indicating diffusion-controlled growth, similar to isostatic rim growth behavior. In contrast, the magnesio-calcite layer growth is enhanced compared to isostatic conditions. Triaxial compression at given time shows no significant change of dolomite rim thickness (11±2 μm) and width of magnesio-calcite layers (33±5 μm) with increasing stress. In torsion experiments, reaction layer thickness and grain size decrease from the center (low stress/strain) to the edge (high strain/stress) of samples. Chemical analysis shows nearly stoichiometric composition of dolomite palisades, but enhanced Ca content within granular grains, indicating local disequilibrium with magnesio-calcite, in particular for twisted samples. The shift from local equilibrium is ˜3 mol% in triaxial compression and ˜7 mol% in torsion. Electron backscatter diffraction analysis reveals a crystallographic preferred orientation (CPO) within the reaction layers with [0001] axes parallel to the compression/rotation axis and poles of {2-1-10} and {10-10} prismatic planes parallel to the reaction interface. Compared to isostatic annealing, the CPO is more pronounced and the amount of low-angle grain boundaries is increased. At the imposed experimental conditions, most of the bulk deformation is accommodated by calcite single, which is stronger than magnesite. Application of flow laws for magnesio-calcite and dolomite suggest that the fine-grained reaction products should deform by grain boundary diffusion creep, resulting in lower flow strength than the single crystal reactants. However, microstructural observations indicate that deformation of granular dolomite and magnesio-calcite is at least partially assisted by dislocation creep, which would result in an almost similar strength to calcite. Therefore, flattening of the reaction layers during triaxial compression may be counterbalanced by enhanced reaction rates, resulting in almost constant layer thickness, independent of the applied stress. For simple shear, the reduced reaction kinetics in the high stress/strain region of twisted samples may be related to increased nucleation rates, resulting in a lower grain size and rim thickness.

Discrimination of osteoarthritic and rheumatoid human synovial cells in culture by nuclear image analysis.

PubMed

Delage, B; Giroud, F; Monet, J D; Ekindjian, O G; Cals, M J

1999-06-01

Rheumatoid arthritic (RA) and osteoarthritic (OA) synovial cells in culture differ in their metabolic and proliferative behaviour. To assess links between these properties and nuclear changes, we used image analysis to study chromatin texture, together with nuclear morphometry and densitometry of OA and RA cells in primary culture. Chromatin pattern at the third day (D3) was heterogeneous and granular with chromatin clumps whereas at the final stage (D11) of culture a homogeneous and finely granular chromatin texture was observed. This evolution indicates global chromatin decondensation. These characteristics were more marked for RA than for OA nuclei. At each culture time, RA nuclei could be discriminated with high confidence from OA ones from parameters evaluating the organization of the chromatine texture. Nuclear image analysis is thus a useful tool for investigating synovial cell biology.

Composite carbon foam electrode

DOEpatents

Mayer, Steven T.; Pekala, Richard W.; Kaschmitter, James L.

1997-01-01

Carbon aerogels used as a binder for granularized materials, including other forms of carbon and metal additives, are cast onto carbon or metal fiber substrates to form composite carbon thin film sheets. The thin film sheets are utilized in electrochemical energy storage applications, such as electrochemical double layer capacitors (aerocapacitors), lithium based battery insertion electrodes, fuel cell electrodes, and electrocapacitive deionization electrodes. The composite carbon foam may be formed by prior known processes, but with the solid particles being added during the liquid phase of the process, i.e. prior to gelation. The other forms of carbon may include carbon microspheres, carbon powder, carbon aerogel powder or particles, graphite carbons. Metal and/or carbon fibers may be added for increased conductivity. The choice of materials and fibers will depend on the electrolyte used and the relative trade off of system resistivty and power to system energy.

Subcellular targeting and interactions among the Potato virus X TGB proteins.

PubMed

Samuels, Timmy D; Ju, Ho-Jong; Ye, Chang-Ming; Motes, Christy M; Blancaflor, Elison B; Verchot-Lubicz, Jeanmarie

2007-10-25

Potato virus X (PVX) encodes three proteins named TGBp1, TGBp2, and TGBp3 which are required for virus cell-to-cell movement. To determine whether PVX TGB proteins interact during virus cell-cell movement, GFP was fused to each TGB coding sequence within the viral genome. Confocal microscopy was used to study subcellular accumulation of each protein in virus-infected plants and protoplasts. GFP:TGBp2 and TGBp3:GFP were both seen in the ER, ER-associated granular vesicles, and perinuclear X-bodies suggesting that these proteins interact in the same subdomains of the endomembrane network. When plasmids expressing CFP:TGBp2 and TGBp3:GFP were co-delivered to tobacco leaf epidermal cells, the fluorescent signals overlapped in ER-associated granular vesicles indicating that these proteins colocalize in this subcellular compartment. GFP:TGBp1 was seen in the nucleus, cytoplasm, rod-like inclusion bodies, and in punctate sites embedded in the cell wall. The puncta were reminiscent of previous reports showing viral proteins in plasmodesmata. Experiments using CFP:TGBp1 and YFP:TGBp2 or TGBp3:GFP showed CFP:TGBp1 remained in the cytoplasm surrounding the endomembrane network. There was no evidence that the granular vesicles contained TGBp1. Yeast two hybrid experiments showed TGBp1 self associates but failed to detect interactions between TGBp1 and TGBp2 or TGBp3. These experiments indicate that the PVX TGB proteins have complex subcellular accumulation patterns and likely cooperate across subcellular compartments to promote virus infection.

Settlement statistics of a granular layer composed of polyhedral particles

NASA Astrophysics Data System (ADS)

Quezada, Juan Carlos; Saussine, Gilles; Breul, Pierre; Radjai, Farhang

2013-06-01

We use 3D contact dynamics simulations to investigate the mechanical equilibrium and settlement of a granular material composed of irregular polyhedral particles confined between two horizontal frictional planes. We show that, as a consequence of mobilized wall-particle friction force at the top and bottom boundaries, the transient deformation induced by a constant vertical load increment is controlled by the aspect ratio (thickness over width) of the packing as well as the stress ratio. The transient deformation declines considerably for increasingly smaller aspect ratios and grows with the stress ratio. From the simulation data for a large number of independent configurations, we find that sample-to-sample fluctuations of the deformation have a broad distribution and they scale with the average deformation.

Granular Segregation Driven by Particle Interactions

NASA Astrophysics Data System (ADS)

Lozano, C.; Zuriguel, I.; Garcimartín, A.; Mullin, T.

2015-05-01

We report the results of an experimental study of particle-particle interactions in a horizontally shaken granular layer that undergoes a second order phase transition from a binary gas to a segregation liquid as the packing fraction C is increased. By focusing on the behavior of individual particles, the effect of C is studied on (1) the process of cluster formation, (2) cluster dynamics, and (3) cluster destruction. The outcomes indicate that the segregation is driven by two mechanisms: attraction between particles with the same properties and random motion with a characteristic length that is inversely proportional to C . All clusters investigated are found to be transient and the probability distribution functions of the separation times display a power law tail, indicating that the splitting probability decreases with time.

Granular flows on erodible layers: type and evolution of flow and deposit structures

NASA Astrophysics Data System (ADS)

Crosta, G.; De Blasio, F.; De Caro, M.; Volpi, G.; Frattini, P.

2012-04-01

The interaction of a fast moving landslide mass with the basal layer over which movement takes place has been discussed in previous contributions. Nevertheless, the evolution of the structures within the moving mass and the erodible layer are still to be described in detail (Hungr and Evans, 2004; Crosta et al., 1992, 2006, 2009, 2011; Dufresne et al., 2010; Mangeney et al., 2010) and modeling results (Crosta et al., 2006, 2009, 2011; Mangeney et al., 2010). We present some of the results from a campaign of laboratory experiments aimed at studying the evolution of a granular flow at the impact with and during the successive spreading over a cohesionless erodible layer. We performed these test to study the processes and to collect data and evidences to compare them with the results of numerical simulations and to verify capabilities of numerical codes. The laboratory setup consists of an inclined slope and an horizontal sector where release and transport, and deposition take place, respectively. Materials used for the tests are: a uniform rounded siliceous sand (Hostun sand; 0.125-0.5 mm) commonly adopted in lab tests because free of scale effects, and a gravel made of angular elements (12 mm in ave. size). Both the materials have been tested in dry conditions. Different slope angles have been tested (40, 45, 50, 55, 50, 66°) as well as different thicknesses of the erodible layer (0, 0.5, 1, 2 cm) and volumes of the released material (1.5, 3, 5, 9.6 liters). Tests have been monitored by means of a high speed camera and the pre- and post-failure geometries have been surveyed by means of a laser scanner. Deposit description allowed also the computation of volumes and the characterization of the different structures developed and frozen into the deposit. Experiments allowed us to observe the extreme processes occurring during the movement and the mise en place of the deposits. In particular, we observe the formation of a clear wave-like feature developing during the movement and deposition along the flatter model sector. Crosta G. (1992) An example of unusual complex landslide: from a rockfall to a dry granular flow. Geol. Romana, 30, 175-184 Crosta G.B., S. Imposimato, D.G. Roddeman (2006) Continuum numerical modelling of flow-like landslides. Landslides from massive rock slope failure, Evans, S.G., Scarascia Mugnozza, G., Strom, A., Hermanns, R., (eds) NATO Science Series, Earth and Environmental Sciences, 49, 211-232 Crosta, G.B., Imposimato, S., and D.G. Roddeman, (2008a) Approach to numerical modelling of long runout landslides. Hong Kong, GCO, Dec. 2007, Proc Inter. Forum on Landslide Disaster Management, 20 pp. Crosta, G.B., Imposimato, S., and D.G. Roddeman, (2008b) Numerical modelling of entrainment/deposition in rock and debris-avalanches. Engineering Geology, 109, 1-2, 135-145. Crosta, G. B., Imposimato, S., and D. Roddeman (2009) Numerical modeling of 2-D granular step collapse on erodible and nonerodible surface. J. Geophys. Res., 114,F03020. Crosta, G. B., Imposimato, S., D. Roddeman, P. Frattini (2011) On controls of flow-like landslide evolution by an erodible layer. Proceedings of the Second World Landslide Forum - 3-7 October 2011, Rome Dufresne, A., Davies, T., McSaveney, M. (2010) Influence of runout-path material on emplacement of the Round Top rock avalanche, New Zealand. Earth Surf. Proc. Land. 35, 190-201. Hungr O, Evans SG. (2004) Entrainment of debris in rock avalanches; an analysis of a long run-out mechanism. Geological Society of America Bulletin 116(9-10): 1240-1252. Mangeney, A., Roche, O., Hungr, O., Mangold, Faccanoni, G., and Lucas, A. , (2010). Erosion and mobility in granular collapse over sloping beds. J. Geophys. Res. - Earth Surface, 115, F03040

A Novel Marker for Purkinje Cells, Ribosomal Protein MPS1/S27: Expression of MPS1 in Human Cerebellum.

PubMed

Fernandez-Pol, J Alberto

2016-01-01

The ribosomal protein metallopanstimulin-1 (MPS1/S27) serves critical survival purposes in cell division, in normal and cancerous cells; for this reason, selective pressures of evolution have conserved the DNA sequences encoding MPS1/S27 in Archaea and Eukariotic cells. The expression of MPS1/S27 protein in human adult cerebellum has not been established. The presence of MPS1/S27, was screened in paraffin-embedded human adult brain specimens processed for tissue inmunohistochemistry. Affinity-purified specific antibodies were directed against the N-terminus of MPS1. The antibodies to MPS1 detected Purkinje cells (PC) and their dendrites. In PC, MPS1 antigen-positive staining was found in: the nucleolus, which was strongly stained; ribosomes attached to the external nuclear membrane; cytoplasm of PC, with strong staining in a punctuate fashion; the soma-attached large dendrite trunks of PC, which were MPS1 antigen-positive; and the granular cell layer, where cellular staining in a few cells that appeared to resemble smaller PC was observed. Since MPS1 is involved in cell division, DNA repair, and ribosomal biogenesis, it may be a useful antigen for studying processes such as protein synthesis, oncogenesis, regeneration, aging, and perhaps diseases of the human cerebellum. Copyright© 2016, International Institute of Anticancer Research (Dr. John G. Delinasios), All rights reserved.

Development of a Full-Thickness Human Skin Equivalent In Vitro Model Derived from TERT-Immortalized Keratinocytes and Fibroblasts

PubMed Central

Reijnders, Christianne M.A.; van Lier, Amanda; Roffel, Sanne; Kramer, Duco; Scheper, Rik J.

2015-01-01

Currently, human skin equivalents (HSEs) used for in vitro assays (e.g., for wound healing) make use of primary human skin cells. Limitations of primary keratinocytes and fibroblasts include availability of donor skin and donor variation. The use of physiologically relevant cell lines could solve these limitations. The aim was to develop a fully differentiated HSE constructed entirely from human skin cell lines, which could be applied for in vitro wound-healing assays. Skin equivalents were constructed from human TERT-immortalized keratinocytes and fibroblasts (TERT-HSE) and compared with native skin and primary HSEs. HSEs were characterized by hematoxylin–eosin and immunohistochemical stainings with markers for epidermal proliferation and differentiation, basement membrane (BM), fibroblasts, and the extracellular matrix (ECM). Ultrastructure was determined with electron microscopy. To test the functionality of the TERT-HSE, burn and cold injuries were applied, followed by immunohistochemical stainings, measurement of reepithelialization, and determination of secreted wound-healing mediators. The TERT-HSE was composed of a fully differentiated epidermis and a fibroblast-populated dermis comparable to native skin and primary HSE. The epidermis consisted of proliferating keratinocytes within the basal layer, followed by multiple spinous layers, a granular layer, and cornified layers. Within the TERT-HSE, the membrane junctions such as corneosomes, desmosomes, and hemidesmosomes were well developed as shown by ultrastructure pictures. Furthermore, the BM consisted of a lamina lucida and lamina densa comparable to native skin. The dermal matrix of the TERT-HSE was more similar to native skin than the primary construct, since collagen III, an ECM marker, was present in TERT-HSEs and absent in primary HSEs. After wounding, the TERT-HSE was able to reepithelialize and secrete inflammatory wound-healing mediators. In conclusion, the novel TERT-HSE, constructed entirely from human cell lines, provides an excellent opportunity to study in vitro skin biology and can also be used for drug targeting and testing new therapeutics, and ultimately, for incorporating into skin-on-a chip in the future. PMID:26135533

Development of a Full-Thickness Human Skin Equivalent In Vitro Model Derived from TERT-Immortalized Keratinocytes and Fibroblasts.

PubMed

Reijnders, Christianne M A; van Lier, Amanda; Roffel, Sanne; Kramer, Duco; Scheper, Rik J; Gibbs, Susan

2015-09-01

Currently, human skin equivalents (HSEs) used for in vitro assays (e.g., for wound healing) make use of primary human skin cells. Limitations of primary keratinocytes and fibroblasts include availability of donor skin and donor variation. The use of physiologically relevant cell lines could solve these limitations. The aim was to develop a fully differentiated HSE constructed entirely from human skin cell lines, which could be applied for in vitro wound-healing assays. Skin equivalents were constructed from human TERT-immortalized keratinocytes and fibroblasts (TERT-HSE) and compared with native skin and primary HSEs. HSEs were characterized by hematoxylin-eosin and immunohistochemical stainings with markers for epidermal proliferation and differentiation, basement membrane (BM), fibroblasts, and the extracellular matrix (ECM). Ultrastructure was determined with electron microscopy. To test the functionality of the TERT-HSE, burn and cold injuries were applied, followed by immunohistochemical stainings, measurement of reepithelialization, and determination of secreted wound-healing mediators. The TERT-HSE was composed of a fully differentiated epidermis and a fibroblast-populated dermis comparable to native skin and primary HSE. The epidermis consisted of proliferating keratinocytes within the basal layer, followed by multiple spinous layers, a granular layer, and cornified layers. Within the TERT-HSE, the membrane junctions such as corneosomes, desmosomes, and hemidesmosomes were well developed as shown by ultrastructure pictures. Furthermore, the BM consisted of a lamina lucida and lamina densa comparable to native skin. The dermal matrix of the TERT-HSE was more similar to native skin than the primary construct, since collagen III, an ECM marker, was present in TERT-HSEs and absent in primary HSEs. After wounding, the TERT-HSE was able to reepithelialize and secrete inflammatory wound-healing mediators. In conclusion, the novel TERT-HSE, constructed entirely from human cell lines, provides an excellent opportunity to study in vitro skin biology and can also be used for drug targeting and testing new therapeutics, and ultimately, for incorporating into skin-on-a chip in the future.

Formation of membrane-bound inclusions and their associations with cytoplasmic channels in early prophase male meiocytes of Althaea rosea (L.) Cavan.

PubMed

Luo, Xin Juan; Liu, Xu Hao; Wang, Chong Ying; Wang, Xin Yu

2008-04-01

To characterize the cytoplasmic structure reorganization during plant meiosis, the male meiocytes of Althaea rosea (L.) Cavan were examined under the combination of light and electron microscopy. Light microscopic observation of the toluidine blue-stained thick resin sections of young anthers revealed that the meiocytes of sporogenous cell stage were extremely voluminous and variable in shape and division plane. The cell walls (CWs) between some meiocytes were discontinuous at one or several site(s). These discontinuous portions varied between 0.2 and 3.0 microm in length. In addition, it was found that some meiocytes were able to produce protuberances that extended into another meiocyte. When transversally sectioned, the protuberance extending to another cell looked like a small cell lying in another cell. Transmission electron microscopy (TEM) showed that there were many long flat ER cisternae that were actively wrapping around a portion of cytoplasm in the male meiocytes at the sporogenous cell stage. During pre-meiosis interphase and early prophase I, a number of huge (0.5-1.0 microm diameter) spherical membrane-bound inclusions (MBIs) lined by single or double layer(s) of membrane were formed, each membrane actually representing one tightly appressed endoplasmic reticulum (ER) cisterna. The MBIs contained many granular, lamellar and fibrillar structures, and even small MBIs. Moreover, it was found that the MBIs could associate with the cytoplasmic channels (CCs) on CWs to release their contents into the cytoplasm of the opposite cell or directly extend from one cell to another through the CC. Taking all the data together, it is suggested that association of the MBIs and other organelles with CCs possibly functions in eliminating the non-identity of cytoplasm of the male meiocytes caused probably by the random asymmetric division observed at sporogenous cell phase, so as to ensure production of a large number of identical functional male gametes required for successful fertilization.

Lithium delays the radiation-induced apoptotic process in external granule cells of mouse cerebellum.

PubMed

Inouye, M; Yamamura, H; Nakano, A

1995-09-01

Proliferating cells of the external granular layer (EGL) in the developing cerebellum are highly sensitive to ionizing radiation. We examined the effect of lithium, an inhibitor of intracellular signaling, on the manifestation of radiation-induced apoptosis. Newborn mice were exposed to 0.5 Gy gamma-irradiation alone, or first were treated with lithium (10 mumol/g, SC) then given 0.5 Gy irradiation 2 hr later. The EGL was examined histologically for apoptosis at various times after treatment. Apoptotic cells increased rapidly, peaked (about 14%) 6 hr after irradiation, then decreased gradually to the control level by 24 hr. Prior treatment with lithium delayed the manifestation of apoptosis, the peak appearing at 12 hr. The disappearance of dead cells was delayed for about one day. The lithium concentration in the whole brain increased rapidly, being 30 micrograms/g at the time of irradiation and remaining at more than 40 micrograms/g for 40 hr. Lithium is reported to inhibit guanine-nucleotide binding to G proteins as well as phosphoinositide turnover. Of the variety of lesions induced by radiation, DNA double strand breaks are the most important source of cell lethality. The present findings, however, suggest that cyclic AMP-mediated and/or phosphoinositidemediated signaling systems regulate radiation-induced apoptosis.

The fibrous form of intracellular inclusion bodies in recombinant variant fibrinogen-producing cells is specific to the hepatic fibrinogen storage disease-inducible variant fibrinogen.

PubMed

Arai, Shinpei; Ogiwara, Naoko; Mukai, Saki; Takezawa, Yuka; Sugano, Mitsutoshi; Honda, Takayuki; Okumura, Nobuo

2017-06-01

Fibrinogen storage disease (FSD) is a rare disorder that is characterized by the accumulation of fibrinogen in hepatocytes and induces liver injury. Six mutations in the γC domain (γG284R, γT314P, γD316N, the deletion of γG346-Q350, γG366S, and γR375W) have been identified for FSD. Our group previously established γ375W fibrinogen-producing Chinese hamster ovary (CHO) cells and observed aberrant large granular and fibrous forms of intracellular inclusion bodies. The aim of this study was to investigate whether fibrous intracellular inclusion bodies are specific to FSD-inducible variant fibrinogen. Thirteen expression vectors encoding the variant γ-chain were stably or transiently transfected into CHO cells expressing normal fibrinogen Aα- and Bβ-chains or HuH-7 cells, which were then immunofluorescently stained. Six CHO and HuH-7 cell lines that transiently produced FSD-inducible variant fibrinogen presented the fibrous (3.2-22.7 and 2.1-24.5%, respectively) and large granular (5.4-25.5 and 7.7-23.9%) forms of intracellular inclusion bodies. Seven CHO and HuH-7 cell lines that transiently produced FSD-non-inducible variant fibrinogen only exhibit the large granular form. These results demonstrate that transiently transfected variant fibrinogen-producing CHO cells and inclusion bodies of the fibrous form may be useful in non-invasive screening for FSD risk factors for FSD before its onset.

Granular parakeratosis.

PubMed

Martín, José M; Pinazo, Isabel; Molina, Inmaculada; Monteagudo, Carlos; Villalón, Guillermo; Jordá, Esperanza

2008-07-01

A healthy 62-year-old woman was referred to our dermatology department with a 1-month history of a pruritic axillary eruption. On examination, multiple erythematous and brownish hyperkeratotic papules were seen in both axillae. Some of these lesions coalesced into plaques, with small areas of sparing, and a background erythematous color was also found in the axillary vaults (Fig. 1). There was no involvement of other intertriginous sites and there were no associated systemic symptoms. The patient was not obese. The patient had removed the hair from her axillae with wax 3 weeks before the development of the eruption. Moreover, she had changed her antiperspirant 1 week before the onset of the lesions. A cutaneous biopsy for histologic analysis was performed. Histologically, the stratum corneum was thickened, with persistent nuclei together with countless small basophilic granules. The granular layer was preserved and, in some areas, hypergranulosis was found (Fig. 2). These findings were characteristic of granular parakeratosis. The cutaneous lesions resolved completely after 1 week of treatment with topical betamethasone dipropionate and gentamicin sulfate (twice daily). The patient was urged to discontinue her use of deodorants.

Dynamic of Air Invasion in an Immersed Granular Layer

NASA Astrophysics Data System (ADS)

Varas, G.; Ramos, G.; Géminard, J. C.; Vidal, V.

2014-12-01

Displacement processes (typically, grains displaced by a fluid) are the driving mechanism which control the dynamics of many geological processes (e.g. oil extraction, air sparging, piercement structures). They also play an important role in a wide range of industrial applications, from ground water hydrology and soil mechanics to agricultural engineering. The interaction between one or more moving fluids (e.g. rising gas immersed in a granular medium) and grains control the dynamics of these phenomena. Due to their economic and ecological importance, it is essential to understand the variety and potentiality of these phenomena. When an ascending air passes trough an immersed granular bed its fluidized producing the grains to start to move. When this process is repeated, its created a fluidized zone that evolves over time. Here, we investigate the morphology and dynamics of the region invaded by air as a function of a dimensionless parameter χ which accounts for the relative effects of the gravity and the capillarity. We propose new experimental observations on the air invasion regimes and on the morphology of the fluidized zone, in particular its growth dynamics.

The Mechanical Response of Multifunctional Battery Systems

NASA Astrophysics Data System (ADS)

Tsutsui, Waterloo

The current state of the art in the field of the mechanical behavior of electric vehicle (EV) battery cells is limited to quasi-static analysis. The lack of published data in the dynamic mechanical behavior of EV battery cells blinds engineers and scientists with the uncertainty of what to expect when EVs experience such unexpected events as intrusions to their battery systems. To this end, the recent occurrences of several EVs catching fire after hitting road debris even make this topic timelier. In order to ensure the safety of EV battery, it is critical to develop quantitative understanding of battery cell mechanical behavior under dynamic compressive loadings. Specifically, the research focuses on the dynamic mechanical loading effect on the standard "18650" cylindrical lithium-ion battery cells. In the study, the force-displacement and voltage-displacement behavior of the battery cells were analyzed experimentally at two strain rates, two state-of-charges, and two unit-cell configurations. The results revealed the strain rate sensitivity of their mechanical responses with the solid sacrificial elements. When the hollow sacrificial cells are used, on the other hand, effect was negligible up to the point of densification strength. Also, the high state-of-charge appeared to increase the stiffness of the battery cells. The research also revealed the effectiveness of the sacrificial elements on the mechanical behavior of a unit cell that consists of one battery cell and six sacrificial elements. The use of the sacrificial elements resulted in the delayed initiation of electric short circuit. Based on the analysis of battery behavior at the cell level, granular battery assembly, a battery pack, was designed and fabricated. The behavior of the granular battery assembly was analyzed both quasistatically and dynamically. Building on the results of the research, various research plans were proposed. Through conducting the research, we sought to answer the following research questions: Could we use battery cells and packs as a part of vehicle structures? Could we use battery cells and packs as a part of vehicle impact energy absorption structure? Based on the research results, the answer to the first question is "yes." However, the granular battery assembly configuration is not suitable as a load-bearing battery structure since the main purpose of granular battery assembly, apart from energy storage for vehicle propulsion, is to work as a kinetic energy dissipation device. The answer to the second question is also "yes." However, the kinetic energy dissipation is mainly performed by the sacrificial elements surrounding the battery cells.

Effect of mechanical cleaning with granular material on the permeability of submerged membranes in the MBR process.

PubMed

Siembida, B; Cornel, P; Krause, S; Zimmermann, B

2010-07-01

The research on fouling reduction and permeability loss in membrane bioreactors (MBRs) was carried out at two MBR pilot plants with synthetic and real wastewater. On the one hand, the effect of mechanical cleaning with an abrasive granular material on the performance of a submerged MBR process was tested. Additionally, scanning electron microscopy (SEM) measurements and integrity tests were conducted to check whether the membrane material was damaged by the granulate.The results indicate that the fouling layer formation was significantly reduced by abrasion using the granular material. This technique allowed a long-term operation of more than 600 days at a flux up to 40 L/(m2 h) without chemical cleaning of the membranes. Moreover, it was demonstrated that the membrane bioreactor (MBR) with granulate could be operated with more than 20% higher flux compared to a conventional MBR operation. SEM images and integrity tests showed that in consequence of abrasive cleaning, the granular material left brush marks on the membrane surface, however, the membrane function was not affected.In a parallel experimental set up, the impact of the operationally defined "truly soluble fraction" <0.04 microm from wastewater and activated sludge on the ultrafiltration membrane fouling characteristics was investigated. It was shown that the permeability loss was caused predominantly by the colloidal fraction >0.04 microm rather than by the dissolved fraction of wastewater and activated sludge.

Vigorous convection in a sunspot granular light bridge

NASA Astrophysics Data System (ADS)

Lagg, Andreas; Solanki, Sami K.; van Noort, Michiel; Danilovic, Sanja

2014-08-01

Context. Light bridges are the most prominent manifestation of convection in sunspots. The brightest representatives are granular light bridges composed of features that appear to be similar to granules. Aims: An in-depth study of the convective motions, temperature stratification, and magnetic field vector in and around light bridge granules is presented with the aim of identifying similarities and differences to typical quiet-Sun granules. Methods: Spectropolarimetric data from the Hinode Solar Optical Telescope were analyzed using a spatially coupled inversion technique to retrieve the stratified atmospheric parameters of light bridge and quiet-Sun granules. Results: Central hot upflows surrounded by cooler fast downflows reaching 10 km s-1 clearly establish the convective nature of the light bridge granules. The inner part of these granules in the near surface layers is field free and is covered by a cusp-like magnetic field configuration. We observe hints of field reversals at the location of the fast downflows. The quiet-Sun granules in the vicinity of the sunspot are covered by a low-lying canopy field extending radially outward from the spot. Conclusions: The similarities between quiet-Sun and light bridge granules point to the deep anchoring of granular light bridges in the underlying convection zone. The fast, supersonic downflows are most likely a result of a combination of invigorated convection in the light bridge granule due to radiative cooling into the neighboring umbra and the fact that we sample deeper layers, since the downflows are immediately adjacent to the slanted walls of the Wilson depression. The two movies are available in electronic form at http://www.aanda.org

A possible mechanism of NK cell-lineage granular lymphocyte proliferative disorder (NK-GLPD) in a patient with chronic active Epstein-Barr virus infection (CAEBV) and severe hypersensitivity to mosquito bites (SHMB).

PubMed

Ohshima, Shiro; Ishii, Masaru; Asada, Hideo; Tatekawa, Toyoshi; Yamaguchi, Norihiko; Kobayashi, Hideyuki; Ishii, Taeko; Mima, Toru; Kawase, Ichiro; Saeki, Yukihiko

2002-08-01

We report the case of a young female patient with chronic active Epstein-Barr virus infection (CAEBV) and severe hypersensitivity to mosquito bites (SHMB). She showed a marked increase of NK cell population in peripheral blood. The NK cell population was suggested to be infected with EBV, and to be oligoclonal by Southern blotting using an EBV genome terminal-repeat probe. The NK cells aberrantly expressed CD25, a high affinity receptor for IL-2, and showed an augmented in vitro proliferative response to IL-2. Moreover, they also showed enhanced expression of both Fas-ligand and Bcl-2, and resistance to in vitro Fas-induced apoptotic cell death (Fas-ACD). Taken together, these observations suggested that both the augmentation of proliferative response to IL-2 and the decrease in Fas-ACD may cause NK cell lineage granular lymphocyte proliferative disorder (NK-GLPD) in patients with CAEBV and SHMB.

The emotional cerebellum.

PubMed

Strata, Piergiorgio

2015-10-01

Great attention has been given so far to cerebellar control of posture and of skilled movements despite the well-demonstrated interconnections between the cerebellum and the autonomic nervous system. Here is a review of the link between these two structures and a report on the recently acquired evidence for its involvement in the world of emotions. In rodents, the reversible inactivation of the vermis during the consolidation or the reconsolidation period hampers the retention of the fear memory trace. In this region, there is a long-term potentiation of both the excitatory synapses between the parallel fibres and the Purkinje cells and of the feed-forward inhibition mediated by molecular layer interneurons. This concomitant potentiation ensures the temporal fidelity of the system. Additional contacts between mossy fibre terminals and Golgi cells provide morphological evidence of the potentiation of another feed-forward inhibition in the granular layer. Imaging experiments show that also in humans the cerebellum is activated during mental recall of emotional personal episodes and during learning of a conditioned or unconditioned association involving emotions. The vermis participates in fear learning and memory mechanisms related to the expression of autonomic and motor responses of emotions. In humans, the cerebellar hemispheres are also involved at a higher emotional level. The importance of these findings is evident when considering the cerebellar malfunctioning in psychiatric diseases like autism and schizophrenia which are characterized behaviourally by emotion processing impairments.

Alternating anoxic feast/aerobic famine condition for improving granular sludge formation in sequencing batch airlift reactor at reduced aeration rate.

PubMed

Wan, Junfeng; Bessière, Yolaine; Spérandio, Mathieu

2009-12-01

In this study the influence of a pre-anoxic feast period on granular sludge formation in a sequencing batch airlift reactor is evaluated. Whereas a purely aerobic SBR was operated as a reference (reactor R2), another reactor (R1) was run with a reduced aeration rate and an alternating anoxic-aerobic cycle reinforced by nitrate feeding. The presence of pre-anoxic phase clearly improved the densification of aggregates and allowed granular sludge formation at reduced air flow rate (superficial air velocity (SAV)=0.63cms(-1)). A low sludge volume index (SVI(30)=45mLg(-1)) and a high MLSS concentration (9-10gL(-1)) were obtained in the anoxic/aerobic system compared to more conventional results for the aerobic reactor. A granular sludge was observed in the anoxic/aerobic system whilst only flocs were observed in the aerobic reference even when operated at a high aeration rate (SAV=2.83cms(-1)). Nitrification was maintained efficiently in the anoxic/aerobic system even when organic loading rate (OLR) was increased up to 2.8kgCODm(-3)d(-1). In the contrary nitrification was unstable in the aerobic system and dropped at high OLR due to competition between autotrophic and heterotrophic growth. The presence of a pre-anoxic period positively affected granulation process via different mechanisms: enhancing heterotrophic growth/storage deeper in the internal anoxic layer of granule, reducing the competition between autotrophic and heterotrophic growth. These processes help to develop dense granular sludge at a moderate aeration rate. This tends to confirm that oxygen transfer is the most limiting factor for granulation at reduced aeration. Hence the use of an alternative electron acceptor (nitrate or nitrite) should be encouraged during feast period for reducing energy demand of the granular sludge process.

Bedrock erosion by sliding wear in channelized granular flow

NASA Astrophysics Data System (ADS)

Hung, C. Y.; Stark, C. P.; Capart, H.; Smith, B.; Maia, H. T.; Li, L.; Reitz, M. D.

2014-12-01

Boundary forces generated by debris flows can be powerful enough to erode bedrock and cause considerable damage to infrastructure during runout. Bedrock wear can be separated into impact and sliding wear processes. Here we focus on sliding wear. We have conducted experiments with a 40-cm-diameter grainflow-generating rotating drum designed to simulate dry channelized debris flows. To generate sliding erosion, we placed a 20-cm-diameter bedrock plate axially on the back wall of the drum. The rotating drum was half filled with 2.3-mm-diameter grains, which formed a thin grain-avalanching layer with peak flow speed and depth close to the drum axis. The whole experimental apparatus was placed on a 100g-ton geotechnical centrifuge and, in order to scale up the stress level, spun to a range of effective gravity levels. Rates and patterns of erosion of the bedrock plate were mapped after each experiment using 3d micro-photogrammetry. High-speed video and particle tracking were employed to measure granular flow dynamics. The resulting data for granular velocities and flow geometry were used to estimate impulse exchanges and forces on the bedrock plate. To address some of the complexities of granular flow under variable gravity levels, we developed a continuum model framed around a GDR MiDi rheology. This model allowed us to scale up boundary forcing while maintaining the same granular flow regime, and helped us to understand important aspects of the flow dynamics including e.g. fluxes of momentum and kinetic energy. In order to understand the detailed processes of boundary forcing, we performed numerical simulations with a new contact dynamics model. This model confirmed key aspects of our continuum model and provided information on second-order behavior such as fluctuations in the forces acting on the wall. By combining these measurements and theoretical analyses, we have developed and calibrated a constitutive model for sliding wear that is a threshold function of granular velocity and stress.

Ultrastructural findings in lung biopsy material from children with congenital heart defects.

PubMed Central

Meyrick, B.; Reid, L.

1980-01-01

The ultrastructural features of pulmonary arteries are described in lung biopsy material from 6 children with congenital heart defects. Right ventricular hypertrophy was found in all 6 children and increased pulmonary artery pressure in all but one. The presence of muscle in smaller and more peripheral arteries than expected for the age of the child was detected in all cases. Ultrastructural examination of the peripheral arteries revealed, for the first time, in the nonmuscular regions of human arterial walls, pericytes and intermediate cells (previously shown to be precursor smooth-muscle cells); in addition, new arterial muscle was found in the normally nonmuscular region. In the 4 cases where medial thickness of the normally muscular arteries was increased, the smooth-muscle cells were hypertrophied and the extracellular connective tissue increased. In all cases, junctions between endothelial cells and smooth-muscle cells, intermediate cells, or pericytes were found. These changes are similar to those described in the rat with hypoxia-induced pulmonary hypertension. In addition, in 2 of the 6 cases, bundles of nerve axons in Schwann cell sheaths were found in adventitial layer of small, intraacinar muscular arteries (not previously demonstrated ultrastructurally at this site in the human lung); varicosities with agranular and granular vesicles, probably adrenergic, were also identified. Images Figure 4 Figure 5 Figure 1 Figure 2 Figure 3 PMID:7446706

Ries Bunte Breccia revisited: Indications for the presence of water in Itzing and Otting drill cores and implications for the emplacement process

NASA Astrophysics Data System (ADS)

Pietrek, Alexa; Kenkmann, Thomas

2016-07-01

We reassessed two drill cores of the Bunte Breccia deposits of the Ries crater, Germany. The objectives of our study were the documentation of evidence for water in the Bunte Breccia, the evaluation of how that water influenced the emplacement processes, and from which preimpact water reservoir it was derived. The Bunte Breccia in both cores can be structured into a basal layer composed mainly of local substrate material, overlain by texturally and compositionally diverse, crater-derived breccia units. The basal layer is composed of the youngest sediments (Tertiary clays and Upper Jurassic limestone) and has a razor-sharp boundary to the upper breccia units, which are composed of older rocks of Upper Jurassic to Upper Triassic age. Sparse material exchange occurred between the basal layer and the rest of the Bunte Breccia. Fluids predominantly came from the Tertiary and the Upper Triassic sandstone formation. In the basal layer, Tertiary clays were subjected to intense, ductile deformation, indicating saturation with water. This suggests that water was mixed into the matrix, creating a fluidized basal layer with a strong shear localization. In the upper units, Upper Triassic sandstones are intensely deformed by granular flow. The texture requires that the rocks were disaggregated into granular sand. Vaporization of pore water probably aided fragmentation of these rocks. In the Otting core, hot suevite (T > 600 °C) covered the Bunte Breccia shortly after its emplacement. Vertically oriented gas escape pipes in suevite partly emanate directly at the contact to the Bunte Breccia. They indicate that the Bunte Breccia contained a substantial amount of water in the upper part that was vaporized and escaped through these vents.

Granular rheology: measuring boundary forces with laser-cut leaf springs

NASA Astrophysics Data System (ADS)

Tang, Zhu; Brzinski, Theodore A.; Daniels, Karen E.

2017-06-01

In granular physics experiments, it is a persistent challenge to obtain the boundary stress measurements necessary to provide full a rheological characterization of the dynamics. Here, we describe a new technique by which the outer boundary of a 2D Couette cell both confines the granular material and provides spatially- and temporally- resolved stress measurements. This key advance is enabled by desktop laser-cutting technology, which allows us to design and cut linearly-deformable walls with a specified spring constant. By tracking the position of each segment of the wall, we measure both the normal and tangential stress throughout the experiment. This permits us to calculate the amount of shear stress provided by basal friction, and thereby determine accurate values of μ(I).

Remediation of Perfluoroalkyl Contaminated Aquifers Using an In-situ Two-layer Barrier: Laboratory Batch and Column Study

DTIC Science & Technology

2013-04-01

the only possible pathway which is unfortunately less potent. Thus, the perfluorination in PFC renders these compounds essentially inert to those...5.1 EXPERIMENTS ....................................................................................................21 5.1.1 SORPTION ISOTHERMS...19 Figure 13. Sorption isotherm of laccase on granular activated carbon at 25°C. .....................20 Figure 14

Dynamic shear jamming in granular suspensions

NASA Astrophysics Data System (ADS)

Peters, Ivo; Majumdar, Sayantan; Jaeger, Heinrich

2014-11-01

Jamming by shear allows a frictional granular packing to transition from an unjammed state into a jammed state while keeping the system volume and average packing fraction constant. Shear jamming of dry granular media can occur quasi-statically, but boundaries are crucial to confine the material. We perform experiments in aqueous starch suspension where we apply shear using a rheometer with a large volume (400 ml) cylindrical Couette cell. In our suspensions the packing fraction is sufficiently low that quasi-static deformation does not induce a shear jammed state. Applying a shock-like deformation however, will turn the suspension into a jammed solid. A fully jammed state is reached within tens of microseconds, and can be sustained for at least several seconds. High speed imaging of the initial process reveals a jamming front propagating radially outward through the suspension, while the suspension near the outer boundary remains quiescent. This indicates that granular suspensions can be shear jammed without the need of confining solid boundaries. Instead, confinement is most likely provided by the dynamics in the front region.

Architectonic subdivisions of neocortex in the tree shrew (Tupaia belangeri)

PubMed Central

Wong, Peiyan; Kaas, Jon H.

2010-01-01

Tree shrews are small mammals that bear some semblance to squirrels, but are actually close relatives of primates. Thus, they have been extensively studied as a model for the early stages of primate evolution. In the present study, subdivisions of cortex were reconstructed from brain sections cut in the coronal, sagittal or horizontal planes, and processed for parvalbumin (PV), SMI-32 immunopositive neurofilament protein epitopes, vesicle glutamate transporter 2 (VGluT2), free ionic zinc, myelin, cytochrome oxidase (CO) and Nissl substance. These different procedures revealed similar boundaries between areas, suggesting the detection of functionally relevant borders and allowed a more precise demarcation of cortical areal boundaries. Primary cortical areas were most clearly revealed by the zinc stain, due to the poor staining of layer 4, as thalamocortical terminations lack free ionic zinc. Area 17 (V1) was especially prominent, as the broad layer 4 was nearly free of zinc stain. However, this feature was less pronounced in primary auditory and somatosensory, cortex. In primary sensory areas, thalamocortical terminations in layer 4 densely express VGluT2. Auditory cortex consists of two architectonically distinct subdivisions, a primary core region (Ac), surrounded by a belt region (Ab) that had a slightly less developed koniocellular appearance. Primary motor cortex (M1) was identified by the absence of VGluT2 staining in the poorly developed granular layer 4 and the presence of SMI-32 labeled pyramidal cells in layers 3 and 5. The presence of well-differentiated cortical areas in tree shrews indicates their usefulness in studies of cortical organization and function. PMID:19462403

Immunohistochemical demonstration of keratins in the epidermal layers of the Malayan pangolin (Manis javanica), with remarks on the evolution of the integumental scale armour.

PubMed

Meyer, W; Liumsiricharoen, M; Suprasert, A; Fleischer, L G; Hewicker-Trautwein, M

2013-09-16

Using immunohistochemistry, the study demonstrates the distribution of keratins (pan-keratin with CK1-8, 10, 14-16, 19; keratins CK1, 5, 6, 9, 10; hair keratins AE13, AE14) in the epidermis of the Malayan pangolin (Manis javanica). A varying reaction spectrum was observed for pan-keratin, with body region-dependent negative to very strong reaction intensities. The dorsolateral epidermis exhibited positive reactions only in its vital layers, whereas the abdominal epidermis showed strong positive reactions in the soft two outer strata. The single acidic and basic-to-neutral (cyto)keratins produced clear variations compared to the pan-keratin tinging. E.g., CK1 appeared in all epidermal layers of both body regions, except for the ventral stratum corneum, whereas CK5, 6, 9, 10 were restricted to the soft ventral epidermis. Here, distinctly positive reactions were confined to the stratum granulosum, except for CK6 that appeared in the soft stratum corneum. A different staining pattern was obvious for the hair keratins, i.e., positive reactions of AE13 concentrated only in the granular layer of the dorsal epidermis. In the abdominal epidermis, remarkable tinging for AE14 was visible in the stratum basale, decreasing toward the corneal layer, but was also found in the outer root sheath cells of the hair follicles in the ventral body part. Our findings are discussed related to the evolution of the horny dorsal scales of the pangolin, which may have started from the tail root, projecting forward to the head.

Mechanics of Granular Materials (MGM) Flight Hardware

NASA Technical Reports Server (NTRS)

1997-01-01

A test cell for the Mechanics of Granular Materials (MGM) experiment is shown in its on-orbit configuration in Spacehab during preparations for STS-89. The twin locker to the left contains the hydraulic system to operate the experiment. Sand and soil grains have faces that can cause friction as they roll and slide against each other, or even cause sticking and form small voids between grains. This complex behavior can cause soil to behave like a liquid under certain conditions such as earthquakes or when powders are handled in industrial processes. Mechanics of Granular Materials (MGM) experiments aboard the Space Shuttle use the microgravity of space to simulate this behavior under conditons that carnot be achieved in laboratory tests on Earth. MGM is shedding light on the behavior of fine-grain materials under low effective stresses. Applications include earthquake engineering, granular flow technologies (such as powder feed systems for pharmaceuticals and fertilizers), and terrestrial and planetary geology. Nine MGM specimens have flown on two Space Shuttle flights. Another three are scheduled to fly on STS-107. The principal investigator is Stein Sture of the University of Colorado at Boulder. Note: Because the image on the screen was muted in the original image, its brightness and contrast are boosted in this rendering to make the test cell more visible. Credit: NASA/Marshall Space Flight Center (MSFC)

The Second Spiking Threshold: Dynamics of Laminar Network Spiking in the Visual Cortex

PubMed Central

Forsberg, Lars E.; Bonde, Lars H.; Harvey, Michael A.; Roland, Per E.

2016-01-01

Most neurons have a threshold separating the silent non-spiking state and the state of producing temporal sequences of spikes. But neurons in vivo also have a second threshold, found recently in granular layer neurons of the primary visual cortex, separating spontaneous ongoing spiking from visually evoked spiking driven by sharp transients. Here we examine whether this second threshold exists outside the granular layer and examine details of transitions between spiking states in ferrets exposed to moving objects. We found the second threshold, separating spiking states evoked by stationary and moving visual stimuli from the spontaneous ongoing spiking state, in all layers and zones of areas 17 and 18 indicating that the second threshold is a property of the network. Spontaneous and evoked spiking, thus can easily be distinguished. In addition, the trajectories of spontaneous ongoing states were slow, frequently changing direction. In single trials, sharp as well as smooth and slow transients transform the trajectories to be outward directed, fast and crossing the threshold to become evoked. Although the speeds of the evolution of the evoked states differ, the same domain of the state space is explored indicating uniformity of the evoked states. All evoked states return to the spontaneous evoked spiking state as in a typical mono-stable dynamical system. In single trials, neither the original spiking rates, nor the temporal evolution in state space could distinguish simple visual scenes. PMID:27582693

Glucose acutely decreases pH of secretory granules in mouse pancreatic islets. Mechanisms and influence on insulin secretion.

PubMed

Stiernet, Patrick; Guiot, Yves; Gilon, Patrick; Henquin, Jean-Claude

2006-08-04

Glucose-induced insulin secretion requires a rise in beta-cell cytosolic Ca2+ ([Ca2+]c) that triggers exocytosis and a mechanistically unexplained amplification of the action of [Ca2+]c. Insulin granules are kept acidic by luminal pumping of protons with simultaneous Cl- uptake to maintain electroneutrality. Experiments using patched, dialyzed beta-cells prompted the suggestion that acute granule acidification by glucose underlies amplification of insulin secretion. However, others found glucose to increase granular pH in intact islets. In this study, we measured islet granular pH with Lysosensor DND-160, a fluorescent dye that permits ratiometric determination of pH < 6 in acidic compartments. Stimulation of mouse islets with glucose reversibly decreased granular pH by mechanisms that are dependent on metabolism and Cl- ions but independent of changes in [Ca2+]c and protein kinase A or C activity. Granular pH was increased by concanamycin (blocker of the vesicular type H+-ATPase) > methylamine (weak base) > Cl- omission. Concanamycin and methylamine did not alter glucose-induced [Ca2+]c increase in islets but strongly inhibited the two phases of insulin secretion. Omission of Cl- did not affect the first phase but decreased the second phase of both [Ca2+]c and insulin responses. Neither experimental condition affected the [Ca2+]c rise induced by 30 mM KCl, but the insulin responses were inhibited by concanamycin > methylamine and not affected by Cl- omission. The amplification of insulin secretion by glucose was not suppressed. We conclude that an acidic granular pH is important for insulin secretion but that the acute further acidification produced by glucose is not essential for the augmentation of secretion via the amplifying pathway.

Steady and unsteady fluidised granular flows down slopes

NASA Astrophysics Data System (ADS)

Jessop, D. E.; Hogg, A. J.; Gilbertson, M. A.; Schoof, C.

2017-09-01

Fluidisation is the process by which the weight of a bed of particles is supported by a gas flow passing through it from below. When fluidised materials flow down an incline, the dynamics of the motion differ from their non-fluidised counterparts because the granular agitation is no longer required to support the weight of the flowing layer. Instead, the weight is borne by the imposed gas flow and this leads to a greatly increased flow mobility. In this paper, a framework is developed to model this two phase motion by incorporating a kinetic theory description for the particulate stresses generated by the flow. In addition to calculating numerical solutions for fully developed flows, it is shown that for sufficiently thick flows there is often a local balance between the production and dissipation of the granular temperature. This phenomenon permits an asymptotic reduction of the full governing equations and the identification of a simple state in which the volume fraction of the flow is uniform. The results of the model are compared with new experimental measurements of the internal velocity profiles of steady granular flows down slopes. The distance covered with time by unsteady granular flows down slopes and along horizontal surfaces and their shapes are also measured and compared with theoretical predictions developed for flows that are thin relative to their streamwise extent. For the horizontal flows, it was found that resistance from the sidewalls was required in addition to basal resistance to capture accurately the unsteady evolution of the front position and the depth of the current and for situations in which side-wall drag dominates, similarity solutions are found for the experimentally-measured motion.

Modeling of Abrasion and Crushing of Unbound Granular Materials During Compaction

NASA Astrophysics Data System (ADS)

Ocampo, Manuel S.; Caicedo, Bernardo

2009-06-01

Unbound compacted granular materials are commonly used in engineering structures as layers in road pavements, railroad beds, highway embankments, and foundations. These structures are generally subjected to dynamic loading by construction operations, traffic and wheel loads. These repeated or cyclic loads cause abrasion and crushing of the granular materials. Abrasion changes a particle's shape, and crushing divides the particle into a mixture of many small particles of varying sizes. Particle breakage is important because the mechanical and hydraulic properties of these materials depend upon their grain size distribution. Therefore, it is important to evaluate the evolution of the grain size distribution of these materials. In this paper an analytical model for unbound granular materials is proposed in order to evaluate particle crushing of gravels and soils subjected to cyclic loads. The model is based on a Markov chain which describes the development of grading changes in the material as a function of stress levels. In the model proposed, each particle size is a state in the system, and the evolution of the material is the movement of particles from one state to another in n steps. Each step is a load cycle, and movement between states is possible with a transition probability. The crushing of particles depends on the mechanical properties of each grain and the packing density of the granular material. The transition probability was calculated using both the survival probability defined by Weibull and the compressible packing model developed by De Larrard. Material mechanical properties are considered using the Weibull probability theory. The size and shape of the grains, as well as the method of processing the packing density are considered using De Larrard's model. Results of the proposed analytical model show a good agreement with the experimental tests carried out using the gyratory compaction test.

Numerical simulations of stick-slip in fluid saturated granular fault gouge

NASA Astrophysics Data System (ADS)

Dorostkar, O.; Johnson, P. A.; Guyer, R. A.; Marone, C.; Carmeliet, J.

2016-12-01

Fluids play a key role in determining the frictional strength and stability of faults. For example, fluid flow and fluid-solid interaction in fault gouge can trigger seismicity, alter earthquake nucleation properties and cause fault zone weakening. We present results of 3D numerical simulations of stick-slip behavior in dry and saturated granular fault gouge. In the saturated case, the gouge is fully saturated and drainage is possible through the boundaries. We model the solid phase (particles) with the discrete element method (DEM) while the fluid is described by the Navier-Stokes equations and solved by computational fluid dynamics (CFD). In our model, granular gouge is sheared between two rough plates under boundary conditions of constant normal stress and constant shearing velocity at the layer boundaries. A phase-space study including shearing velocity and normal stress is taken to identify the conditions for stick-slip regime. We analyzed slip events for dry and saturated cases to determine shear stress drop, released kinetic energy and compaction. The presence of fluid tends to cause larger slip events. We observe a close correlation between the kinetic energy of the particles and of the fluid. In short, during slip, fluid flow induced by the failure and compaction of the granular system, mobilizes the particles, which increases their kinetic energy, leading to greater slip. We further observe that the solid-fluid interaction forces are equal or larger than the solid-solid interaction forces during the slip event, indicating the important influence of the fluid on the granular system. Our simulations can explain the behaviors observed in experimental studies and we are working to apply our results to tectonic faults.

Cytidine-5-diphosphocholine supplement in early life induces stable increase in dendritic complexity of neurons in the somatosensory cortex of adult rats

PubMed Central

Rema, V.; Bali, K.K.; Ramachandra, R.; Chugh, M.; Darokhan, Z.; Chaudhary, R.

2008-01-01

Cytidine-5-diphosphocholine (CDP-choline or citicholine) is an essential molecule that is required for biosynthesis of cell membranes. In adult humans it is used as a memory-enhancing drug for treatment of age-related dementia and cerebrovascular conditions. However the effect of CDP-choline on perinatal brain is not known. We administered CDP-choline to Long Evans rats each day from conception (maternal ingestion) to postnatal day 60 (P60). Pyramidal neurons from supragranular layers 2/3, granular layer 4 and infragranular layer 5 of somatosensory cortex were examined with Golgi–Cox staining at P240. CDP-choline treatment significantly increased length and branch points of apical and basal dendrites. Sholl analysis shows that the complexity of apical and basal dendrites of neurons is maximal in layers 2/3 and layer 5. In layer 4 significant increases were seen in basilar dendritic arborization. CDP-choline did not increase the number of primary basal dendrites on neurons in the somatosensory cortex. Primary cultures from somatosensory cortex were treated with CDP-choline to test its effect on neuronal survival. CDP-choline treatment neither enhanced the survival of neurons in culture nor increased the number of neurites. However significant increases in neurite length, branch points and total area occupied by the neurons were observed. We conclude that exogenous supplementation of CDP-choline during development causes stable changes in neuronal morphology. Significant increase in dendritic growth and branching of pyramidal neurons from the somatosensory cortex resulted in enlarging the surface area occupied by the neurons which we speculate will augment processing of sensory information. PMID:18619738

Granular segregation driven by particle interactions.

PubMed

Lozano, C; Zuriguel, I; Garcimartín, A; Mullin, T

2015-05-01

We report the results of an experimental study of particle-particle interactions in a horizontally shaken granular layer that undergoes a second order phase transition from a binary gas to a segregation liquid as the packing fraction C is increased. By focusing on the behavior of individual particles, the effect of C is studied on (1) the process of cluster formation, (2) cluster dynamics, and (3) cluster destruction. The outcomes indicate that the segregation is driven by two mechanisms: attraction between particles with the same properties and random motion with a characteristic length that is inversely proportional to C. All clusters investigated are found to be transient and the probability distribution functions of the separation times display a power law tail, indicating that the splitting probability decreases with time.

Differentiation of grain orientation with corrosive and colour etching on a granular bainitic steel.

PubMed

Reisinger, S; Ressel, G; Eck, S; Marsoner, S

2017-08-01

This study presents a detailed verification of the etching methods with Nital and Klemm on a granular bainitic steel. It is shown that both methods allow the identification of the crystal orientation, whereas Klemm etching enables also a quantification of the apparent phases, as also retained austenite can be distinguished from the other bainitic microstructures. A combination of atom probe tomography with electron-back-scattered-diffraction showed that both etching methods emphasize the bainitic {100} crystal orientation. However, a cross-section produced by focused ion beam evidenced that Klemm etching leads to the formation of a topography of the different oriented bainitic crystals that directly affects the thickness and therefore the apparent colour of the deposited layer formed during etching. Copyright © 2017 Elsevier Ltd. All rights reserved.

Flow of Dense Granular Suspensions on an Inclined Plane

NASA Astrophysics Data System (ADS)

Bonnoit, C.; Lanuza, J.; Lindner, A.; Clément, E.

2008-07-01

We investigate the flow behavior of dense granular suspensions, by the use of an inclined plane. The suspensions are prepared at high packing fractions and consist of spherical non-Brownian particles density matched with the suspending fluid. On the inclined plane, we perform a systematic study of the surface velocity as a function of the layer thickness for various flow rates and tilt angles. We perform measurements on a classical rheometer (parallel-plate rheometer) that is shown to be in good agreement with existing models, up to a volume fraction of 50%. Comparing these results, we show that the flow on an inclined plane can, up to a volume fraction of 50%, indeed be described by a purely viscous model in agreement with the results from classical rheometry.

Modeling interface exchange coupling: Effect on switching of granular FePt films

NASA Astrophysics Data System (ADS)

Abugri, Joseph B.; Visscher, P. B.; Su, Hao; Gupta, Subhadra

2015-07-01

To raise the areal density of magnetic recording to ˜1 Tbit/in2, there has been much recent work on the use of FePt granular films, because their high perpendicular anisotropy allows small grains to be stable. However, their coercivity may be higher than available write-head fields. One approach to reduce the coercivity is to heat the grain (heat assisted magnetic recording). Another strategy is to add a soft capping layer to help nucleate switching via exchange coupling with the hard FePt grains. We have simulated a model of such a capped medium and have studied the effect of the strength of the interface exchange and thickness of hard layer and soft layer on the overall coercivity. Although the magnetization variation within such boundary layers may be complex, the net effect of the boundary can often be modeled as an infinitely thin interface characterized by an interface exchange energy density—we show how to do this consistently in a micromagnetic simulation. Although the switching behavior in the presence of exchange, magnetostatic, and external fields is quite complex, we show that by adding these fields one at a time, the main features of the M-H loop can be understood. In particular, we find that even without hard-soft interface exchange, magnetostatic coupling eliminates the zero-field kink in the loop, so that the absence of the kink does not (as has sometimes been assumed) imply exchange coupling. The computations have been done with a public-domain micromagnetics simulator that has been adapted to easily simulate arrays of grains.

Cytology of human caudomedial cingulate, retrosplenial, and caudal parahippocampal cortices.

PubMed

Vogt, B A; Vogt, L J; Perl, D P; Hof, P R

2001-09-24

Brodmann showed areas 26, 29, 30, 23, and 31 on the human posterior cingulate gyrus without marking sulcal areas. Histologic studies of retrosplenial areas 29 and 30 identify them on the ventral bank of the cingulate gyrus (CGv), whereas standardized atlases show area 30 on the surface of the caudomedial region. This study evaluates all areas on the CGv and caudomedial region with rigorous cytologic criteria in coronal and oblique sections Nissl stained or immunoreacted for neuron-specific nuclear binding protein and nonphosphorylated neurofilament proteins (NFP-ir). Ectosplenial area 26 has a granular layer with few large pyramidal neurons below. Lateral area 29 (29l) has a dense granular layer II-IV and undifferentiated layers V and VI. Medial area 29 (29m) has a layer III of medium and NFP-ir pyramids and a layer IV with some large, NFP-ir pyramidal neurons that distinguish it from areas 29l, 30, and 27. Although area 29m is primarily on the CGv, a terminal branch can extend onto the caudomedial lobule. Area 30 is dysgranular with a variable thickness layer IV that is interrupted by large NFP-ir neurons in layers IIIc and Va. Although area 30 does not appear on the surface of the caudomedial lobule, a terminal branch can form less that 1% of this gyrus. Area 23a is isocortex with a clear layer IV and large, NFP-ir neurons in layers IIIc and Va. Area 23b is similar to area 23a but with a thicker layer IV, more large neurons in layer Va, and a higher density of NFP-ir neurons in layer III. The caudomedial gyral surface is composed of areas 23a and 23b and a caudal extension of area 31. Although posterior area 27 and the parasubiculum are similar to rostral levels, posterior area 36' differs from rostral area 36. Subregional flat maps show that retrosplenial cortex is on the CGv, most of the surface of caudomedial cortex is areas 23a, 23b, and 31, and the retrosplenial/parahippocampal border is at the ventral edge of the splenium. Thus, Brodmann's map understates the rostral extent of retrosplenial cortex, overstates its caudoventral extent, and abridges the caudomedial extent of area 23. Copyright 2001 Wiley-Liss, Inc.

Laser readable thermoluminescent radiation dosimeters and methods for producing thereof

DOEpatents

Braunlich, Peter F.; Tetzlaff, Wolfgang

1989-01-01

Thin layer thermoluminescent radiation dosimeters for use in laser readable dosimetry systems, and methods of fabricating such thin layer dosimeters. The thin layer thermoluminescent radiation dosimeters include a thin substrate made from glass or other inorganic materials capable of withstanding high temperatures and high heating rates. A thin layer of a thermoluminescent phoshphor material is heat bonded to the substrate using an inorganic binder such as glass. The dosimeters can be mounted in frames and cases for ease in handling. Methods of the invention include mixing a suitable phosphor composition and binder, both being in particulate or granular form. The mixture is then deposited onto a substrate such as by using mask printing techniques. The dosimeters are thereafter heated to fuse and bond the binder and phosphor to the substrate.

Mesoscale simulations of shock compaction of a granular ceramic: effects of mesostructure and mixed-cell strength treatment

NASA Astrophysics Data System (ADS)

Derrick, J. G.; LaJeunesse, J. W.; Davison, T. M.; Borg, J. P.; Collins, G. S.

2018-04-01

The shock response of granular materials is important in a variety of contexts but the precise dynamics of grains during compaction is poorly understood. Here we use 2D mesoscale numerical simulations of the shock compaction of granular tungsten carbide to investigate the effect of internal structure within the particle bed and ‘stiction’ between grains on the shock response. An increase in the average number of contacts with other particles, per particle, tends to shift the Hugoniot to higher shock velocities, lower particle velocities and lower densities. This shift is sensitive to inter-particle shear resistance. Eulerian shock physics codes approximate friction between, and interlocking of, grains with their treatment of mixed cell strength (stiction) and here we show that this has a significant effect on the shock response. When studying the compaction of particle beds it is not common to quantify the pre-compaction internal structure, yet our results suggest that such differences should be taken into account, either by using identical beds or by averaging results over multiple experiments.

Transformation around intruders in granular media

NASA Astrophysics Data System (ADS)

Jop, Pierre; Merceron, Aymeric; Sauret, Alban

2017-06-01

Sintering, glass melting and other industrially relevant processes turn batches of grains into homogeneous products. Such processes involve coupled chemical and physical transformations of the granular packing. For sake of simplicity, we study how local evolutions on grains (volume decreases for example) entail mechanical rearrangements in the overall pile. Inert bidisperse metallic disks are mixed and confined in a vertical 2D cell. At the bottom of this set-up, initial intruders (one or two) have been previously set and mechanically linked to a linear motorized jack. While we quasi-statically pull the intruder(s) downward out of the cell at constant speed and constant liberated surface, we tracked the surrounding granular packing. Events largely distributed both spatially and temporally occur around intruders. We focus on the influence of the distance between the intruders on the local dynamic of the packing. We compare the distribution of the size of the event and their frequency as function of the relative position of the intruder, as a function of their radius. We show that their influence decreases rapidly. At short distance the mechanical perturbation induced by one intruder can destabilize the packing around the other.

Capacitor with a composite carbon foam electrode

DOEpatents

Mayer, Steven T.; Pekala, Richard W.; Kaschmitter, James L.

1999-01-01

Carbon aerogels used as a binder for granularized materials, including other forms of carbon and metal additives, are cast onto carbon or metal fiber substrates to form composite carbon thin film sheets. The thin film sheets are utilized in electrochemical energy storage applications, such as electrochemical double layer capacitors (aerocapacitors), lithium based battery insertion electrodes, fuel cell electrodes, and electrocapacitive deionization electrodes. The composite carbon foam may be formed by prior known processes, but with the solid partides being added during the liquid phase of the process, i.e. prior to gelation. The other forms of carbon may include carbon microspheres, carbon powder, carbon aerogel powder or particles, graphite carbons. Metal and/or carbon fibers may be added for increased conductivity. The choice of materials and fibers will depend on the electrolyte used and the relative trade off of system resistivity and power to system energy.

Method for fabricating composite carbon foam

DOEpatents

Mayer, Steven T.; Pekala, Richard W.; Kaschmitter, James L.

2001-01-01

Carbon aerogels used as a binder for granularized materials, including other forms of carbon and metal additives, are cast onto carbon or metal fiber substrates to form composite carbon thin film sheets. The thin film sheets are utilized in electrochemical energy storage applications, such as electrochemical double layer capacitors (aerocapacitors), lithium based battery insertion electrodes, fuel cell electrodes, and electrocapacitive deionization electrodes. The composite carbon foam may be formed by prior known processes, but with the solid particles being added during the liquid phase of the process, i.e. prior to gelation. The other forms of carbon may include carbon microspheres, carbon powder, carbon aerogel powder or particles, graphite carbons. Metal and/or carbon fibers may be added for increased conductivity. The choice of materials and fibers will depend on the electrolyte used and the relative trade off of system resistivity and power to system energy.

Capacitor with a composite carbon foam electrode

DOEpatents

Mayer, S.T.; Pekala, R.W.; Kaschmitter, J.L.

1999-04-27

Carbon aerogels used as a binder for granularized materials, including other forms of carbon and metal additives, are cast onto carbon or metal fiber substrates to form composite carbon thin film sheets. The thin film sheets are utilized in electrochemical energy storage applications, such as electrochemical double layer capacitors (aerocapacitors), lithium based battery insertion electrodes, fuel cell electrodes, and electrocapacitive deionization electrodes. The composite carbon foam may be formed by prior known processes, but with the solid particles being added during the liquid phase of the process, i.e. prior to gelation. The other forms of carbon may include carbon microspheres, carbon powder, carbon aerogel powder or particles, graphite carbons. Metal and/or carbon fibers may be added for increased conductivity. The choice of materials and fibers will depend on the electrolyte used and the relative trade off of system resistivity and power to system energy. 1 fig.

Morphological and immunohistochemical analysis of apoptosis in the cerebellum of rats subjected to focal cerebral ischemia with or without alcoholism model.

PubMed

Carvalho, Camila Albuquerque Melo de; Tirapelli, Daniela Pretti da Cunha; Rodrigues, Andressa Romualdo; Lizarte, Fermino Sanches; Novais, Paulo Cézar; Silva, Jairo Pinheiro; Carlotti, Carlos Gilberto; Colli, Benedicto Oscar; Tirapelli, Luís Fernando

2016-09-01

To evaluated histopathological changes, morphometric and expression of proteins CASPASE-3, BCL-2 and XIAP related to apoptosis in the cerebellum after induction of temporary focal cerebral ischemia followed by reperfusion, with or without a model of chronic alcoholism. Fifty Wistar rats were used and divided into: control group (C), sham group (S), ischemic group (I), alcoholic group (A), and ischemic and alcoholic group (IA). The cerebellum samples collected were stained for histopathological and morphometric analysis and immunohistochemistry study. Histopathological changes were observed a greater degree in animals in groups A and IA. The morphometric study showed no difference in the amount of cells in the granular layer of the cerebellum between the groups. The expression of CASPASE-3 was higher than BCL-2 and XIAP in the groups A and IA. We observed correlation between histopathological changes and the occurrence of apoptosis in cerebellar cortex.

Learning from eponyms: George F. Odland and Odland bodies

PubMed Central

Joshi, Rajiv

2014-01-01

Odland bodies (lamellar) bodies are small sub-cellular structures of size 200-300 nm that are present in the upper spinous and granular cell layers of the epidermis. These act as processing and repository areas for lipids that contribute to the epidermal permeability barrier. They also contain proteases, cathepsin D, kallikrein and other proteins including corneo-desmosins. Recent information also credits them with a role in the local innate immune response as they contain beta 2 defensins, which are anti-microbial peptides with potent activity against Gram-negative bacteria and candida. Odland bodies are important for maintaining homeostasis of the epidermis and are involved in epidermal permeability barrier function, desquamation of keratinocytes, formation of the cornified envelope and in local anti-microbial immunity. This article reviews the structure and functions of these bodies with a brief biography of George F. Odland who first described these bodies in 1960 and whose name is eponymically associated with them. PMID:25165659

Potential mechanisms of cerebellar hypoplasia in prematurity.

PubMed

Tam, Emily W Y

2013-09-01

The cerebellum undergoes dramatic growth and maturation over the neonatal period after preterm birth and is thus particularly sensitive to impaired development due to various clinical factors. Impairments in growth can occur independent of cerebellar parenchymal damage, such as from local hemorrhage, resulting from reduced expression of sonic hedgehog signaling to trigger the appropriate expansion of the granule precursor cells. The primary risk factors for impaired cerebellar development include postnatal glucocorticoid exposure, which has direct effects on the sonic hedgehog pathway, and supratentorial brain injury, including intraventricular hemorrhage and white matter injury, which may result in crossed cerebellar diaschisis and local toxic effects of blood products on the external granular layer. Other cardiorespiratory and nutritional factors may also exist. Impaired cerebellar development is associated with adverse outcomes in motor and cognitive development. New approaches to care to counteract these risk factors may help improve long-term outcome after preterm birth.

Tributyltin exposure causes brain damage in Sebastiscus marmoratus.

PubMed

Zhang, Jiliang; Zuo, Zhenghong; Chen, Rong; Chen, Yixin; Wang, Chonggang

2008-09-01

Tributyltin (TBT) is a ubiquitous marine environmental contaminant characterized primarily by its reproductive toxicity. However, the neurotoxic effect of TBT has not been extensively described, especially in fishes which have a high number of species in the marine environment. This study was conducted to investigate the neurotoxic effects of TBT at environmental levels (1, 10, and 100ngl(-1)) on female Sebastiscus marmoratus. The results showed that TBT exposure induced apoptosis in brain cells of three regions including the pallial areas of the telencephalon, the granular layer of the optic tectum, and the cerebellum. In addition, the increase of reactive oxygen species and nitric oxide levels, and the decrease of Na+/K+-ATPase activity were found in the brain. The results strongly indicated neurotoxicity of TBT to fishes. According to the regions in which apoptosis was found in the brain, TBT exposure might influence the schooling, sensory and motorial functions of fishes.

Measurement of intracellular nitric oxide (NO) production in shrimp haemocytes by flow cytometry.

PubMed

Xian, Jian-An; Guo, Hui; Li, Bin; Miao, Yu-Tao; Ye, Jian-Min; Zhang, Sheng-Peng; Pan, Xun-Bin; Ye, Chao-Xia; Wang, An-Li; Hao, Xuan-Ming

2013-12-01

A flow cytometric method to measure the production of intracellular nitric oxide (NO) was adapted for use with shrimp haemocytes. We applied fluorescent probe 4-amino-5-methylamino-2',7'-difluorofluorescein diacetate (DAF-FM DA) for NO detection in haemocytes from the tiger shrimp Penaeus monodon, and used flow cytometry to quantify fluorescence intensity in individual haemocyte. The optimized protocol for intracellular NO analysis consists to incubate haemocytes with DAF-FM DA at 10 μM for 60 min to determine the mean fluorescence intensity. Result showed that NO was also produced in the untreated shrimp haemocytes. NO level in granular cells and semigranular cells were much higher than that in hyaline cells. Defined by different characteristic of NO content, three subsets of haemocytes were observed. Zymosan A at dose of 10 or 100 particles per haemocyte triggered higher DAF-FM fluorescence intensity in granular and semigranular cells, than PMA that had no significant impact on all three cell types. These results indicate that granular and semigranular cells are the primary cells for NO generation. Cytochalasin B significantly inhibited the NO level induced by zymosan A. NG-Monomethyl-L-arginine (L-NMMA) and diphenylene iodonium chloride (DPI) significantly suppressed the DAF-FM fluorescence in haemocytes, but apocynin could not modulate it, indicating that the DAF-FM fluorescence was closely related to the activity of NO-synthase pathway. The NO donor sodium nitroprusside (SNP) improved the DAF-FM fluorescence in haemocytes, while the NO scavenger C-PTIO (2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide) significantly decreased the fluorescence, demonstrating that the fluorescence intensity of DAF-FM is mainly dependent on the intracellular NO level.

Cholesterol overload impairing cerebellar function: the promise of natural products.

PubMed

El-Sayyad, Hassan I H

2015-05-01

The cerebellum is the part of the brain most involved in controlling motor and cognitive function. The surface becomes convoluted, forming folia that have a characteristic internal structure of three layers including molecular, Purkinje cell, and granular layer. This complex neural network gives rise to a massive signal-processing capability. Cholesterol is a major constituent, derived by de novo synthesis and the blood-brain barrier. Cholesterol is tightly regulated between neurons and glia-that is, astrocytes, microglia, and oligodendrocytes-and is essential for normal brain development. The axon is wrapped by myelin (cholesterol, phospholipids, and glycosphingolipids) and made up of membranes of oligodendrocytes, separated by periodic gaps in the myelin sheath, called nodes of Ranvier. Hypercholesterolemia is associated with increased oxidative stress and the development of neurotoxicity and Alzheimer's disease. Treatment with natural products has been found to support improved brain function and reduce low-density-lipoprotein cholesterol level. Fish oil is one such product; among the many plant products are: Morus alba leaves, fruit, and bark; pomegranate fruit and peel; Barley β - glucans; date palm; and Allium sativum. The therapeutic potential was discussed in relation with the antilipidemic drugs, statins (HMG-CoA reductase inhibitors). Copyright © 2015 Elsevier Inc. All rights reserved.

Fast convergence of learning requires plasticity between inferior olive and deep cerebellar nuclei in a manipulation task: a closed-loop robotic simulation

PubMed Central

Luque, Niceto R.; Garrido, Jesús A.; Carrillo, Richard R.; D'Angelo, Egidio; Ros, Eduardo

2014-01-01

The cerebellum is known to play a critical role in learning relevant patterns of activity for adaptive motor control, but the underlying network mechanisms are only partly understood. The classical long-term synaptic plasticity between parallel fibers (PFs) and Purkinje cells (PCs), which is driven by the inferior olive (IO), can only account for limited aspects of learning. Recently, the role of additional forms of plasticity in the granular layer, molecular layer and deep cerebellar nuclei (DCN) has been considered. In particular, learning at DCN synapses allows for generalization, but convergence to a stable state requires hundreds of repetitions. In this paper we have explored the putative role of the IO-DCN connection by endowing it with adaptable weights and exploring its implications in a closed-loop robotic manipulation task. Our results show that IO-DCN plasticity accelerates convergence of learning by up to two orders of magnitude without conflicting with the generalization properties conferred by DCN plasticity. Thus, this model suggests that multiple distributed learning mechanisms provide a key for explaining the complex properties of procedural learning and open up new experimental questions for synaptic plasticity in the cerebellar network. PMID:25177290

Mechanics of Granular Materials (MGM) Test Cell

NASA Technical Reports Server (NTRS)

2004-01-01

Test cells comprise specimen sand contained in a latex membrane (with a grid pattern for CCD cameras) between metal end plates and housed in a water-filled Lexan jacket. Experiment flown on STS-79 and STS-89. Principal Investigator: Dr. Stein Sture.

HAMLET (human alpha-lactalbumin made lethal to tumor cells) triggers autophagic tumor cell death.

PubMed

Aits, Sonja; Gustafsson, Lotta; Hallgren, Oskar; Brest, Patrick; Gustafsson, Mattias; Trulsson, Maria; Mossberg, Ann-Kristin; Simon, Hans-Uwe; Mograbi, Baharia; Svanborg, Catharina

2009-03-01

HAMLET, a complex of partially unfolded alpha-lactalbumin and oleic acid, kills a wide range of tumor cells. Here we propose that HAMLET causes macroautophagy in tumor cells and that this contributes to their death. Cell death was accompanied by mitochondrial damage and a reduction in the level of active mTOR and HAMLET triggered extensive cytoplasmic vacuolization and the formation of double-membrane-enclosed vesicles typical of macroautophagy. In addition, HAMLET caused a change from uniform (LC3-I) to granular (LC3-II) staining in LC3-GFP-transfected cells reflecting LC3 translocation during macroautophagy, and this was blocked by the macroautophagy inhibitor 3-methyladenine. HAMLET also caused accumulation of LC3-II detected by Western blot when lysosomal degradation was inhibited suggesting that HAMLET caused an increase in autophagic flux. To determine if macroautophagy contributed to cell death, we used RNA interference against Beclin-1 and Atg5. Suppression of Beclin-1 and Atg5 improved the survival of HAMLET-treated tumor cells and inhibited the increase in granular LC3-GFP staining. The results show that HAMLET triggers macroautophagy in tumor cells and suggest that macroautophagy contributes to HAMLET-induced tumor cell death.

Extracellular polymeric substances govern the surface charge of biogenic elemental selenium nanoparticles.

PubMed

Jain, Rohan; Jordan, Norbert; Weiss, Stephan; Foerstendorf, Harald; Heim, Karsten; Kacker, Rohit; Hübner, René; Kramer, Herman; van Hullebusch, Eric D; Farges, François; Lens, Piet N L

2015-02-03

The origin of the organic layer covering colloidal biogenic elemental selenium nanoparticles (BioSeNPs) is not known, particularly in the case when they are synthesized by complex microbial communities. This study investigated the presence of extracellular polymeric substances (EPS) on BioSeNPs. The role of EPS in capping the extracellularly available BioSeNPs was also examined. Fourier transform infrared (FT-IR) spectroscopy and colorimetric measurements confirmed the presence of functional groups characteristic of proteins and carbohydrates on the BioSeNPs, suggesting the presence of EPS. Chemical synthesis of elemental selenium nanoparticles in the presence of EPS, extracted from selenite fed anaerobic granular sludge, yielded stable colloidal spherical selenium nanoparticles. Furthermore, extracted EPS, BioSeNPs, and chemically synthesized EPS-capped selenium nanoparticles had similar surface properties, as shown by ζ-potential versus pH profiles and isoelectric point measurements. This study shows that the EPS of anaerobic granular sludge form the organic layer present on the BioSeNPs synthesized by these granules. The EPS also govern the surface charge of these BioSeNPs, thereby contributing to their colloidal properties, hence affecting their fate in the environment and the efficiency of bioremediation technologies.

Superior bit error rate and jitter due to improved switching field distribution in exchange spring magnetic recording media

PubMed Central

Suess, D.; Fuger, M.; Abert, C.; Bruckner, F.; Vogler, C.

2016-01-01

We report two effects that lead to a significant reduction of the switching field distribution in exchange spring media. The first effect relies on a subtle mechanism of the interplay between exchange coupling between soft and hard layers and anisotropy that allows significant reduction of the switching field distribution in exchange spring media. This effect reduces the switching field distribution by about 30% compared to single-phase media. A second effect is that due to the improved thermal stability of exchange spring media over single-phase media, the jitter due to thermal fluctuation is significantly smaller for exchange spring media than for single-phase media. The influence of this overall improved switching field distribution on the transition jitter in granular recording and the bit error rate in bit-patterned magnetic recording is discussed. The transition jitter in granular recording for a distribution of Khard values of 3% in the hard layer, taking into account thermal fluctuations during recording, is estimated to be a = 0.78 nm, which is similar to the best reported calculated jitter in optimized heat-assisted recording media. PMID:27245287

Universal stability curve for pattern formation in pulsed gas-solid fluidized beds of sandlike particles

NASA Astrophysics Data System (ADS)

de Martín, Lilian; Ottevanger, Coen; van Ommen, J. Ruud; Coppens, Marc-Olivier

2018-03-01

A granular layer can form regular patterns, such as squares, stripes, and hexagons, when it is fluidized with a pulsating gas flow. These structures are reminiscent of the well-known patterns found in granular layers excited through vibration, but, contrarily to them, they have been hardly explored since they were first discovered. In this work, we investigate experimentally the conditions leading to pattern formation in pulsed fluidized beds and the dimensionless numbers governing the phenomenon. We show that the onset to the instability is universal for Geldart B (sandlike) particles and governed by the hydrodynamical parameters Γ =ua/(utϕ ¯) and f /fn , where ua and f are the amplitude and frequency of the gas velocity, respectively, ut is the terminal velocity of the particles, ϕ ¯ is the average solids fraction, and fn is the natural frequency of the bed. These findings suggest that patterns emerge as a result of a parametric resonance between the kinematic waves originating from the oscillating gas flow and the bulk dynamics. Particle friction plays virtually no role in the onset to pattern formation, but it is fundamental for pattern selection and stabilization.

Pressure evolution and deformation of confined granular media during pneumatic fracturing

NASA Astrophysics Data System (ADS)

Eriksen, Fredrik K.; Toussaint, Renaud; Turquet, Antoine Léo; Mâløy, Knut J.; Flekkøy, Eirik G.

2018-01-01

By means of digital image correlation, we experimentally characterize the deformation of a dry granular medium confined inside a Hele-Shaw cell due to air injection at a constant overpressure high enough to deform it (from 50 to 250 kPa). Air injection at these overpressures leads to the formation of so-called pneumatic fractures, i.e., channels empty of beads, and we discuss the typical deformations of the medium surrounding these structures. In addition we simulate the diffusion of the fluid overpressure into the medium, comparing it with the Laplacian solution over time and relating pressure gradients with corresponding granular displacements. In the compacting medium we show that the diffusing pressure field becomes similar to the Laplace solution on the order of a characteristic time given by the properties of the pore fluid, the granular medium, and the system size. However, before the diffusing pressure approaches the Laplace solution on the system scale, we find that it resembles the Laplacian field near the channels, with the highest pressure gradients on the most advanced channel tips and a screened pressure gradient behind them. We show that the granular displacements more or less always move in the direction against the local pressure gradients, and when comparing granular velocities with pressure gradients in the zone ahead of channels, we observe a Bingham type of rheology for the granular paste (the mix of air and beads), with an effective viscosity μB and displacement thresholds ∇ ⃗Pc evolving during mobilization and compaction of the medium. Such a rheology, with disorder in the displacement thresholds, could be responsible for placing the pattern growth at moderate injection pressures in a universality class like the dielectric breakdown model with η =2 , where fractal dimensions are found between 1.5 and 1.6 for the patterns.

Surface structure of MgO underlayer with Ti diffusion for (002) oriented L10 FePt-based heat assisted magnetic recording media

NASA Astrophysics Data System (ADS)

Hinata, Sintaro; Jo, Shin; Saito, Shin

2018-05-01

Surface morphology of the MgO layer and magnetic properties of FePt-C layer deposited on the MgO were investigated for the FePt-based heat assisted magnetic recording media. Stacking structure of the underlayer for the FePt-C layer was MgO (0-5 nm)/Cr80Mn20 (0-30 nm)/Cr50Ti50 (0-50 nm)/glass sub.. Surface observation result for the MgO film by using an atomic force microscope revealed the existence of nodules with a height of about 2 nm and a network-like convex structure with a height difference of about sub nm (boundary wall, BW) on the MgO crystal grain boundary. Density of the nodules largely depends on the surface roughness of the CrTi layer, RaCrTi and it is suppressed from 10 to 2/0.5 μm2 by reducing RaCrTi from 420 to 260 pm. Height of the BW depends on thickness of the MgO layer, tMgO and it can be suppressed by reducing tMgO to less than 4 nm. From the cross-sectional energy dispersive x-ray mapping, it is clarified that the BW is formed by atomic diffusion of Ti atoms from CrTi layer due to the substrate heating process, and a compound consists of Mg, Ti and O atoms. This BW can be used as a template to magnetically isolate the FePt column in the FePt-based granular film, such as FePt-SiO2, if the size of the BW is reduced to less than 10 nm. M-H loop of the FePt-C granular film deposited on the underlayer showed that the nodule and BW induce oxidation of the FePt grains, and reduction of intergranular exchange coupling.

VGLUT2 mRNA and protein expression in the visual thalamus and midbrain of prosimian galagos (Otolemur garnetti)

PubMed Central

Balaram, Pooja; Takahata, Toru; Kaas, Jon H

2011-01-01

Vesicular glutamate transporters (VGLUTs) control the storage and presynaptic release of glutamate in the central nervous system, and are involved in the majority of glutamatergic transmission in the brain. Two VGLUT isoforms, VGLUT1 and VGLUT2, are known to characterize complementary distributions of glutamatergic neurons in the rodent brain, which suggests that they are each responsible for unique circuits of excitatory transmission. In rodents, VGLUT2 is primarily utilized in thalamocortical circuits, and is strongly expressed in the primary sensory nuclei, including all areas of the visual thalamus. The distribution of VGLUT2 in the visual thalamus and midbrain has yet to be characterized in primate species. Thus, the present study describes the expression of VGLUT2 mRNA and protein across the visual thalamus and superior colliculus of prosimian galagos to provide a better understanding of glutamatergic transmission in the primate brain. VGLUT2 is strongly expressed in all six layers of the dorsal lateral geniculate nucleus, and much less so in the intralaminar zones, which correspond to retinal and superior collicular inputs, respectively. The parvocellular and magnocellular layers expressed VGLUT2 mRNA more densely than the koniocellular layers. A patchy distribution of VGLUT2 positive terminals in the pulvinar complex possibly reflects inputs from the superior colliculus. The upper superficial granular layers of the superior colliculus, with inputs from the retina, most densely expressed VGLUT2 protein, while the lower superficial granular layers, with projections to the pulvinar, most densely expressed VGLUT2 mRNA. The results are consistent with the conclusion that retinal and superior colliculus projections to the thalamus depend highly on the VGLUT2 transporter, as do cortical projections from the magnocellular and parvocellular layers of the lateral geniculate nucleus and neurons of the pulvinar complex. PMID:22984342

Influence of Temperature on Frictional Strength and Healing Properties of Water Saturated Granular Fault Gouges During Dynamic Slip Instabilities

NASA Astrophysics Data System (ADS)

Scuderi, M.; Marone, C.

2012-12-01

The seismic potential of faults, as well as mechanical strength and frictional instability are controlled by the evolution of the real contact area within the fault gouge. Fault gouge is characterized by granular and clay rich material, as the result of continuous wear produced by dynamic or quasi-static slip along the fault plane. In this context, water and thermally-activated physicochemical reactions play a fundamental role in controlling the evolution of friction, via asperity contact properties and processes including hydrolytic weakening, adsorption/desorption, and/or intergranular pressure-solution (IPS). To investigate the role of granular processes and temperature in faulting, we performed shear experiments in water-saturated simulated gouges. We sheared layers of synthetic fault gouge composed of soda-lime glass beads (dia. 105-149 mm) in a double direct shear configuration within a true-triaxial pressure vessel under controlled fluid pressure using DI water. Effective normal stress (σn) was kept constant during shear at 5 MPa, and layer thickness was constantly monitored via a DCDT attached to the ram. Shear stress (τ) was applied via a constant shear displacement rate at layers boundaries. We performed velocity step experiments, during which shearing velocity was increased stepwise from 0.3 to 300 μm/s, and slide-hold-slide tests, with hold times from 1 to 1000 s. During each experiment temperature was kept constant at values of 25, 50 and 75C. Our experiments were conducted in a stick-slip sliding regime. At the end of each run, simulated gouge layers were carefully collected and impregnated with epoxy resin for SEM analysis. For all experiments, stress drop (Δτ) decreases roughly linearly with the log of velocity. With increasing temperature Δτ increases and the velocity dependence varies. Frictional healing is characterized by β = 0.023 change in friction per decade at T = 25C, increasing to β = 0.037 at T = 50C. We find that maximum friction (μmax) increases with increasing temperature, as well as the amount of pre-seismic slip and the corresponding layers dilation. In agreement with previous studies, our data suggest that in water saturated simulated gouges, solid-fluid chemical reactions are enhanced by increasing temperature, which may induce plastic flow and/or intergranular pressure solution at grain junction, controlling μmax, stress drop magnitude and frictional healing. Future work will consider the connection between the observed mechanical behavior and the evolution of grain contact properties.

Capillary pressure-saturation relationships for porous granular materials: Pore morphology method vs. pore unit assembly method

NASA Astrophysics Data System (ADS)

Sweijen, Thomas; Aslannejad, Hamed; Hassanizadeh, S. Majid

2017-09-01

In studies of two-phase flow in complex porous media it is often desirable to have an estimation of the capillary pressure-saturation curve prior to measurements. Therefore, we compare in this research the capability of three pore-scale approaches in reproducing experimentally measured capillary pressure-saturation curves. To do so, we have generated 12 packings of spheres that are representative of four different glass-bead packings and eight different sand packings, for which we have found experimental data on the capillary pressure-saturation curve in the literature. In generating the packings, we matched the particle size distributions and porosity values of the granular materials. We have used three different pore-scale approaches for generating the capillary pressure-saturation curves of each packing: i) the Pore Unit Assembly (PUA) method in combination with the Mayer and Stowe-Princen (MS-P) approximation for estimating the entry pressures of pore throats, ii) the PUA method in combination with the hemisphere approximation, and iii) the Pore Morphology Method (PMM) in combination with the hemisphere approximation. The three approaches were also used to produce capillary pressure-saturation curves for the coating layer of paper, used in inkjet printing. Curves for such layers are extremely difficult to determine experimentally, due to their very small thickness and the presence of extremely small pores (less than one micrometer in size). Results indicate that the PMM and PUA-hemisphere method give similar capillary pressure-saturation curves, because both methods rely on a hemisphere to represent the air-water interface. The ability of the hemisphere approximation and the MS-P approximation to reproduce correct capillary pressure seems to depend on the type of particle size distribution, with the hemisphere approximation working well for narrowly distributed granular materials.

Manifestation of hopping conductivity and granularity within phase diagrams of LaO1-x F x BiS2, Sr1-x La x FBiS2 and related BiS2-based compounds

NASA Astrophysics Data System (ADS)

Arouca, R.; Silva Neto, M. B.; Chaves, C. M.; Nagao, M.; Watauchi, S.; Tanaka, I.; ElMassalami, M.

2017-09-01

Layered BiS 2 -based series, such as LaO 1-x F x BiS 2 and Sr 1-x La x FBiS 2 , offer ideal examples for studying normal and superconducting phase diagram of a solid solution that evolves from a nonmagnetic band-insulator parent. We constructed typical x-T phase diagrams of these systems based on events occurring in thermal evolution of their electrical resistivity, ρ(x, T) . Overall evolution of these diagrams can be rationalized in terms of (i) Mott-Efros-Shklovskii scenario which, within the semiconducting x regime (x_MIT = Mott metal-insulator transition), describes the doping influence on the thermally activated hopping conductivity. (ii) A granular metal (superconductor) scenario which, within x_MIT< x < x_solubility , describes the evolution of normal and superconducting properties in terms of conductance g, Coulomb charging energy E c and Josephson coupling J; their joint influence is usually captured within a g-\\frac{gE_c}{J}-T phase diagram. Based on analysis of the granular character of ρ(x, T) , we converted the x-T diagrams into projected g - T diagrams which, being fundamental, allow a better understanding of evolution of various granular-related properties (in particular the hallmarks of normal-state \\partialρ/\\partial T<0 feature and superconductor-insulator transition) and how such properties are influenced by x, pressure or heat treatment.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Requerey, Iker S.; Iniesta, Jose Carlos Del Toro; Rubio, Luis R. Bellot

We report on the dynamical interaction of quiet-Sun magnetic fields and granular convection in the solar photosphere as seen by Sunrise. We use high spatial resolution (0.″15–0.″18) and temporal cadence (33 s) spectropolarimetric Imaging Magnetograph eXperiment data, together with simultaneous CN and Ca ii H filtergrams from Sunrise Filter Imager. We apply the SIR inversion code to the polarimetric data in order to infer the line of sight velocity and vector magnetic field in the photosphere. The analysis reveals bundles of individual flux tubes evolving as a single entity during the entire 23 minute data set. The group shares amore » common canopy in the upper photospheric layers, while the individual tubes continually intensify, fragment and merge in the same way that chains of bright points in photometric observations have been reported to do. The evolution of the tube cores are driven by the local granular convection flows. They intensify when they are “compressed” by surrounding granules and split when they are “squeezed” between two moving granules. The resulting fragments are usually later regrouped in intergranular lanes by the granular flows. The continual intensification, fragmentation and coalescence of flux results in magnetic field oscillations of the global entity. From the observations we conclude that the magnetic field oscillations first reported by Martínez González et al. correspond to the forcing by granular motions and not to characteristic oscillatory modes of thin flux tubes.« less

On the role of fluids in stick-slip dynamics of saturated granular fault gouge using a coupled computational fluid dynamics-discrete element approach

NASA Astrophysics Data System (ADS)

Dorostkar, Omid; Guyer, Robert A.; Johnson, Paul A.; Marone, Chris; Carmeliet, Jan

2017-05-01

The presence of fault gouge has considerable influence on slip properties of tectonic faults and the physics of earthquake rupture. The presence of fluids within faults also plays a significant role in faulting and earthquake processes. In this paper, we present 3-D discrete element simulations of dry and fluid-saturated granular fault gouge and analyze the effect of fluids on stick-slip behavior. Fluid flow is modeled using computational fluid dynamics based on the Navier-Stokes equations for an incompressible fluid and modified to take into account the presence of particles. Analysis of a long time train of slip events shows that the (1) drop in shear stress, (2) compaction of granular layer, and (3) the kinetic energy release during slip all increase in magnitude in the presence of an incompressible fluid, compared to dry conditions. We also observe that on average, the recurrence interval between slip events is longer for fluid-saturated granular fault gouge compared to the dry case. This observation is consistent with the occurrence of larger events in the presence of fluid. It is found that the increase in kinetic energy during slip events for saturated conditions can be attributed to the increased fluid flow during slip. Our observations emphasize the important role that fluid flow and fluid-particle interactions play in tectonic fault zones and show in particular how discrete element method (DEM) models can help understand the hydromechanical processes that dictate fault slip.

Study of budding yeast colony formation and its characterizations by using circular granular cell

NASA Astrophysics Data System (ADS)

Aprianti, D.; Haryanto, F.; Purqon, A.; Khotimah, S. N.; Viridi, S.

2016-03-01

Budding yeast can exhibit colony formation in solid substrate. The colony of pathogenic budding yeast can colonize various surfaces of the human body and medical devices. Furthermore, it can form biofilm that resists drug effective therapy. The formation of the colony is affected by the interaction between cells and with its growth media. The cell budding pattern holds an important role in colony expansion. To study this colony growth, the molecular dynamic method was chosen to simulate the interaction between budding yeast cells. Every cell was modelled by circular granular cells, which can grow and produce buds. Cohesion force, contact force, and Stokes force govern this model to mimic the interaction between cells and with the growth substrate. Characterization was determined by the maximum (L max) and minimum (L min) distances between two cells within the colony and whether two lines that connect the two cells in the maximum and minimum distances intersect each other. Therefore, it can be recognized the colony shape in circular, oval, and irregular shapes. Simulation resulted that colony formation are mostly in oval shape with little branch. It also shows that greater cohesion strength obtains more compact colony formation.

Fundamental structural characteristics of planar granular assemblies: Self-organization and scaling away friction and initial state.

PubMed

Matsushima, Takashi; Blumenfeld, Raphael

2017-03-01

The microstructural organization of a granular system is the most important determinant of its macroscopic behavior. Here we identify the fundamental factors that determine the statistics of such microstructures, using numerical experiments to gain a general understanding. The experiments consist of preparing and compacting isotropically two-dimensional granular assemblies of polydisperse frictional disks and analyzing the emergent statistical properties of quadrons-the basic structural elements of granular solids. The focus on quadrons is because the statistics of their volumes have been found to display intriguing universal-like features [T. Matsushima and R. Blumenfeld, Phys. Rev. Lett. 112, 098003 (2014)PRLTAO0031-900710.1103/PhysRevLett.112.098003]. The dependence of the structures and of the packing fraction on the intergranular friction and the initial state is analyzed, and a number of significant results are found. (i) An analytical formula is derived for the mean quadron volume in terms of three macroscopic quantities: the mean coordination number, the packing fraction, and the rattlers fraction. (ii) We derive a unique, initial-state-independent relation between the mean coordination number and the rattler-free packing fraction. The relation is supported numerically for a range of different systems. (iii) We collapse the quadron volume distributions from all systems onto one curve, and we verify that they all have an exponential tail. (iv) The nature of the quadron volume distribution is investigated by decomposition into conditional distributions of volumes given the cell order, and we find that each of these also collapses onto a single curve. (v) We find that the mean quadron volume decreases with increasing intergranular friction coefficients, an effect that is prominent in high-order cells. We argue that this phenomenon is due to an increased probability of stable irregularly shaped cells, and we test this using a herewith developed free cell analytical model. We conclude that, in principle, the microstructural characteristics are governed mainly by the packing procedure, while the effects of intergranular friction and initial states are details that can be scaled away. However, mechanical stability constraints suppress slightly the occurrence of small quadron volumes in cells of order ≥6, and the magnitude of this effect does depend on friction. We quantify in detail this dependence and the deviation it causes from an exact collapse for these cells. (vi) We argue that our results support strongly the view that ensemble granular statistical mechanics does not satisfy the uniform measure assumption of conventional statistical mechanics. Results (i)-(iv) have been reported in the aforementioned reference, and they are reviewed and elaborated on here.

Down-regulation of zinc transporter 8 (SLC30A8) in pancreatic beta-cells promotes cell survival

USDA-ARS?s Scientific Manuscript database

The pancreatic islet contains high levels of zinc in granular vesicles of beta-cells where insulin is matured, crystallized, and stored before secretion. Zinc is an essential co-factor for insulin crystallization forming dense core in secretory granules. In insulin-containing secretory granules, zin...

Down-regulation of zinc transporter 8 (SLC30A8) in pancreatic beta-cells promotes cell survival.

USDA-ARS?s Scientific Manuscript database

The pancreatic islet contains high levels of zinc in granular vesicles of ß-cells where insulin is matured, crystallized, and stored before secretion. Zinc is an essential co-factor for insulin crystallization forming dense cores in secretory granules. In insulin-containing secretory granules, zinc ...

Magnetic characteristics and nanostructures of FePt granular films with GeO2 segregant

NASA Astrophysics Data System (ADS)

Ono, Takuya; Moriya, Tomohiro; Hatayama, Masatoshi; Tsumura, Kaoru; Kikuchi, Nobuaki; Okamoto, Satoshi; Kitakami, Osamu; Shimatsu, Takehito

2017-01-01

To realize a granular film composed of L10-FePt grains with high uniaxial magnetic anisotropy energy, Ku, and segregants for energy-assisted magnetic recording, a FePt-GeO2/FePt-C stacked film was investigated in the engineering process. The FePt-GeO2/FePt-C stacked film fabricated at a substrate temperature of 450 °C realized uniaxial magnetic anisotropy, Kugrain , of about 2.5 × 107 erg/cm3, which is normalized by the volume fraction of FePt grains, and a granular structure with an averaged grain size of 7.7 nm. As the thickness of the FePt-GeO2 upper layer was increased to 9 nm, the Ku values were almost constant. That result differs absolutely from the thickness dependences of the other oxide segregant materials such as SiO2 and TiO2. Such differences on the oxide segregant are attributed to their chemical bond. The strong covalent bond of GeO2 is expected to result in high Ku of the FePt-GeO2/FePt-C stacked films.

Electronics and triggering challenges for the CMS High Granularity Calorimeter

NASA Astrophysics Data System (ADS)

Lobanov, A.

2018-02-01

The High Granularity Calorimeter (HGCAL), presently being designed by the CMS collaboration to replace the CMS endcap calorimeters for the High Luminosity phase of LHC, will feature six million channels distributed over 52 longitudinal layers. The requirements for the front-end electronics are extremely challenging, including high dynamic range (0.2 fC-10 pC), low noise (~2000 e- to be able to calibrate on single minimum ionising particles throughout the detector lifetime) and low power consumption (~20 mW/channel), as well as the need to select and transmit trigger information with a high granularity. Exploiting the intrinsic precision-timing capabilities of silicon sensors also requires careful design of the front-end electronics as well as the whole system, particularly clock distribution. The harsh radiation environment and requirement to keep the whole detector as dense as possible will require novel solutions to the on-detector electronics layout. Processing the data from the HGCAL imposes equally large challenges on the off-detector electronics, both for the hardware and incorporated algorithms. We present an overview of the complete electronics architecture, as well as the performance of prototype components and algorithms.

Regularized Moment Equations and Shock Waves for Rarefied Granular Gas

NASA Astrophysics Data System (ADS)

Reddy, Lakshminarayana; Alam, Meheboob

2016-11-01

It is well-known that the shock structures predicted by extended hydrodynamic models are more accurate than the standard Navier-Stokes model in the rarefied regime, but they fail to predict continuous shock structures when the Mach number exceeds a critical value. Regularization or parabolization is one method to obtain smooth shock profiles at all Mach numbers. Following a Chapman-Enskog-like method, we have derived the "regularized" version 10-moment equations ("R10" moment equations) for inelastic hard-spheres. In order to show the advantage of R10 moment equations over standard 10-moment equations, the R10 moment equations have been employed to solve the Riemann problem of plane shock waves for both molecular and granular gases. The numerical results are compared between the 10-moment and R10-moment models and it is found that the 10-moment model fails to produce continuous shock structures beyond an upstream Mach number of 1 . 34 , while the R10-moment model predicts smooth shock profiles beyond the upstream Mach number of 1 . 34 . The density and granular temperature profiles are found to be asymmetric, with their maxima occurring within the shock-layer.

Construction and tests of a fine granularity lead-scintillating fibers calorimeter

NASA Astrophysics Data System (ADS)

Branchini, P.; Ceradini, F.; Corradi, G.; Di Micco, B.; Passeri, A.

2009-04-01

We report the construction and the tests of a small prototype of the lead-scintillating fiber calorimeter of the KLOE experiment, instrumented with multianode photomultipliers to obtain a 16 times finer readout granularity. The prototype is 15 cm wide, 15 radiation lengths deep and is made of 200 layers of fibers 50 cm long. On one side it is read out with an array of 3×5 multianode photomultipliers Hamamatsu type R8900-M16, each segmented with 4×4 anodes, the read out granularity being 240 pixels of 11 × 11 mm2 corresponding to about 64 scintillating fibers each. These are interfaced to the 6 × 6 mm2 pixeled photocathode with truncated pyramid light guides made of Bicron BC-800 plastic to partially transmit the UV light. Each photomultiplier provides also an OR of the 16 last dynodes that is used for trigger. The response of the individual anodes, their relative gain and cross-talk has been measured with the light (440 nm) of a laser illuminating only few fibers on the side opposite to the readout. We finally present the first results of the calorimeter response to cosmic rays in auto-trigger mode.

Construction and first beam-tests of silicon-tungsten prototype modules for the CMS High Granularity Calorimeter for HL-LHC

NASA Astrophysics Data System (ADS)

Jain, S.

2017-03-01

The High Granularity Calorimeter (HGCAL) is the technology choice of the CMS collaboration for the endcap calorimetry upgrade planned to cope with the harsh radiation and pileup environment at the High Luminosity-LHC . The HGCAL is realized as a sampling calorimeter, including an electromagnetic compartment comprising 28 layers of silicon pad detectors with pad areas of 0.5-01. cm2 interspersed with absorbers made from tungsten and copper to form a highly compact and granular device. Prototype modules, based on hexagonal silicon pad sensors, with 128 channels, have been constructed and tested in beams at FNAL and at CERN. The modules include many of the features required for this challenging detector, including a PCB glued directly to the sensor, using through-hole wire-bonding for signal readout and 5 mm spacing between layers—including the front-end electronics and all services. Tests in 2016 have used an existing front-end chip —Skiroc2 (designed for the CALICE experiment for ILC). We present results from first tests of these modules both in the laboratory and with beams of electrons, pions and protons, including noise performance, calibration with mips and electron signals.

Agronomic Effectiveness of Granulated and Powdered P-Exchanged Mg-Al LDH Relative to Struvite and MAP.

PubMed

Everaert, Maarten; Degryse, Fien; McLaughlin, Mike J; De Vos, Dirk; Smolders, Erik

2017-08-16

Layered double hydroxides (LDHs) used to recover P from wastewater have recently been proposed as new slow-release fertilizers. Here, the use of P-exchanged Mg-Al LDHs as powdered or granulated fertilizer is explored and compared with monoammonium phosphate (MAP), a fully water-soluble fertilizer, and with struvite, a recycled phosphate fertilizer with lower solubility. First, these three fertilizers were compared in a 100-day incubation experiment using P diffusion visualization and chemical analysis to assess P release from either granules or powdered fertilizer in three different soils. By the end of the incubation, 74-90% of P remained within the LDH granule, confirming a slow release. Second, a pot experiment was performed with wheat (Triticum aestivum) in an acid and a calcareous soil. The granular treatment resulted in a considerably higher P uptake for MAP compared to LDH and struvite. For the powder treatments, the P uptake was less than for granular MAP and was largely unaffected by the chemical form. The LDHs and struvite showed a lower agronomic effectiveness than granular MAP, but the benefits of their use in P recycling, potential residual value, and environmental benefits may render these slow-release fertilizers attractive.

Comparison of Phenotypic and Functional Characteristics Between Canine Non-B, Non-T Natural Killer Lymphocytes and CD3+CD5dimCD21- Cytotoxic Large Granular Lymphocytes.

PubMed

Lee, Soo-Hyeon; Shin, Dong-Jun; Kim, Yoseop; Kim, Cheol-Jung; Lee, Je-Jung; Yoon, Mee Sun; Uong, Tung Nguyen Thanh; Yu, Dohyeon; Jung, Ji-Youn; Cho, Duck; Jung, Bock-Gie; Kim, Sang-Ki; Suh, Guk-Hyun

2018-01-01

Natural killer (NK) cells play a pivotal role in the immune response against infections and malignant transformation, and adopted transfer of NK cells is thought to be a promising therapeutic approach for cancer patients. Previous reports describing the phenotypic features of canine NK cells have produced inconsistent results. Canine NK cells are still defined as non-B and non-T (CD3 - CD21 - ) large granular lymphocytes. However, a few reports have demonstrated that canine NK cells share the phenotypic characteristics of T lymphocytes, and that CD3 + CD5 dim CD21 - lymphocytes are putative canine NK cells. Based on our previous reports, we hypothesized that phenotypic modulation could occur between these two populations during activation. In this study, we investigated the phenotypic and functional differences between CD3 + CD5 dim CD21 - (cytotoxic large granular lymphocytes) and CD3 - CD5 - CD21 - NK lymphocytes before and after culture of peripheral blood mononuclear cells isolated from normal dogs. The results of this study show that CD3 + CD5 dim CD21 - lymphocytes can be differentiated into non-B, non-T NK (CD3 - CD5 - CD21 - TCRαβ - TCRγδ - GranzymeB + ) lymphocytes through phenotypic modulation in response to cytokine stimulation. In vitro studies of purified CD3 + CD5 dim CD21 - cells showed that CD3 - CD5 - CD21 - cells are derived from CD3 + CD5 dim CD21 - cells through phenotypic modulation. CD3 + CD5 dim CD21 - cells share more NK cell functional characteristics compared with CD3 - CD5 - CD21 - cells, including the expression of T-box transcription factors (Eomes, T-bet), the production of granzyme B and interferon-γ, and the expression of NK cell-related molecular receptors such as NKG2D and NKp30. In conclusion, the results of this study suggest that CD3 + CD5 dim CD21 - and CD3 - CD5 - CD21 - cells both contain a subset of putative NK cells, and the difference between the two populations may be due to the degree of maturation.

Increased apoptosis and reduced neuronal and glial densities in the hippocampus due to nicotine and ethanol exposure in adolescent mice.

PubMed

Oliveira-da-Silva, Andreia; Vieira, Fernanda B; Cristina-Rodrigues, Fabiana; Filgueiras, Cláudio C; Manhães, Alex C; Abreu-Villaça, Yael

2009-10-01

It has been recently shown that nicotine and ethanol interact during adolescence affecting memory/learning and anxiety levels. Considering the role of the hippocampus in both anxiety and memory/learning, we investigated whether adolescent nicotine and/or ethanol administration elicit apoptotic cell death and whether this results in neuronal and/or glial density alterations in the following regions of the hippocampus: granular layer of the dentate gyrus (GrDG), molecular layer (Mol), CA1, CA2 and CA3. From the 30th to the 45th postnatal day, C57BL/6 male and female mice were exposed to nicotine free base (NIC) and/or ethanol (ETOH). Four groups were analyzed: (1) concomitant NIC (50mug/ml in 2% saccharin to drink) and ETOH (25%, 2g/kg i.p. injected every other day) exposure; (2) NIC exposure; (3) ETOH exposure; (4) vehicle. We evaluated cell degeneration (TUNEL assay), neuronal and glial densities (optical disector) and region thicknesses at the end of the period of exposure. Our results demonstrate that ETOH elicited an increase in TUNEL-positive cells relative to the vehicle group in all hippocampal regions. NIC elicited less severe region-dependent effects: the number of TUNEL-positive cells was significantly increased in the Mol and CA1 when compared to the vehicle group. These results were paralleled by reductions in neuronal and glial cells densities, which indicate that both cell types are sensitive to the neurotoxic effects of these drugs. There were no effects on region thicknesses. On the other hand, concomitant NIC and ETOH reduced the adverse effects of the drugs when administered separately. This ability of nicotine and ethanol co-exposure to lessen the adverse effects of nicotine and ethanol may contribute to adolescents co-use and co-abuse of tobacco and alcoholic beverages.

Immunolocalization and Distribution of Rubella Antigen in Fatal Congenital Rubella Syndrome

PubMed Central

Lazar, Mihaela; Perelygina, Ludmila; Martines, Roosecelis; Greer, Patricia; Paddock, Christopher D.; Peltecu, Gheorghe; Lupulescu, Emilia; Icenogle, Joseph; Zaki, Sherif R.

2015-01-01

Background An estimated 100,000 cases of congenital rubella syndrome (CRS) occur worldwide each year. The reported mortality rate for infants with CRS is up to 33%. The cellular mechanisms responsible for the multiple congenital defects in CRS are presently unknown. Here we identify cell types positive for rubella virus (RV) in CRS infants. Methods Cells and organs involved in RV replication were identified in paraffin-embedded autopsy tissues from three fatal case-patients by histopathologic examination and immunohistochemical (IHC) staining using a rabbit polyclonal RV antibody. Normal rabbit antisera and RV antisera preabsorbed with highly purified RV served as negative controls. Results RV antigen was found in interstitial fibroblasts in the heart, adventitial fibroblasts of large blood vessels, alveolar macrophages, progenitor cells of the outer granular layer of the brain, and in capillary endothelium and basal plate in the placenta. The antibody specificity was verified by IHC staining of multiple tissue sections from other infectious disease cases. RV infection of each cell type is consistent with abnormalities which have been identified in patients with CRS, in the heart, large blood vessels, and brain. Antigen distribution was consistent with inflammatory response to vascular injury and systemic spread of RV. Conclusions The identification of RV positive cell types in CRS is important to better understand the pathology and pathogenesis of CRS. PMID:26870820

Leukoencephalopathy Associated with Parvovirus Infection in Cretan Hound Puppies▿

PubMed Central

Schaudien, D.; Polizopoulou, Z.; Koutinas, A.; Schwab, S.; Porombka, D.; Baumgärtner, W.; Herden, C.

2010-01-01

Leukoencephalopathies in dogs encompass presumably inherited conditions such as leukodystrophies, hypomyelination or spongiform degeneration, but other causes, such as virus infections and toxic or nutritional factors, might also play a contributory role. In this report, we provide evidence of parvovirus infection and replication in the brains of five 6-week-old Cretan hound puppies suffering from a puppy shaker syndrome and leukoencephalopathy. Although these puppies belonged to two different litters, they were closely related, tracing back two generations to the same sire. Histologically, a mild to moderate lymphohistiocytic meningitis, with focal lymphohistiocytic leukoencephalitis in two animals, and a mild to moderate vacuolation with myelin loss, mainly in the white matter of the cerebellum was detected. Vacuolation was also found in the corpus callosum, fimbria hippocampi, mesencephalon, capsula interna, basal ganglia, and hypothalamus. By immunohistology and in situ hybridization, either parvoviral antigen, DNA, mRNA, or replicative intermediate DNA were detected in the cerebellum, hippocampus, periventricular areas, corpus callosum, cerebral cortex, medulla oblongata, and spinal cord. Parvovirus antigen, DNA, and mRNA were present in cells of the outer granular layer of the cerebellum and in periventricular cells, most likely representing spongioblasts, glial cells, neurons, endothelial cells, occasional macrophages, and ependymal cells. Sequencing revealed canine parvovirus type 2 stretches. Thus, an association of parvovirus infection with the leukoencephalopathy seems likely, possibly facilitated by a genetic predisposition due to the mode of inbreeding in this particular dog breed. PMID:20592142

Study of composite thin films for applications in high density data storage

NASA Astrophysics Data System (ADS)

Yuan, Hua

Granular Co-alloy + oxide thin films are currently used as the magnetic recording layer of perpendicular media in hard disk drives. The microstructure of these films is composed mainly of fine (7--10 nm) magnetic grains physically surrounded by oxide phases, which produce magnetic isolation of the grains. As a result, the magnetic switching volume is maintained as small as the physical grain size. Consequently, ample number of magnetic switching units can be obtained in one recording bit, in other words, higher signal to noise ratios (SNR) can be achieved. Therefore, a good understanding and control of the microstructure of the films is very important for high areal density magnetic recording media. Interlayers and seedlayers play important roles in controlling the microstructure in terms of grain size, grain size distribution, oxide segregation and orientation dispersion of the crystallographic texture. Developing novel interlayers or seedlayers with smaller grain size is a key approach to produce smaller grain size in the recording layer. This study focuses on how to achieve smaller grain sizes in the recording layer through novel interlayer/seedlayer materials and processes. It also discusses the resulting microstructure in smaller-grain-size thin films. Metal + oxide (e.g. Ru + SiO2) composite thin films were chosen as interlayer and seedlayer materials due to their unique segregated microstructure. Such layers can be grown epitaxially on top of fcc metal seedlayers with good orientation. It can also provide an epitaxial growth template for the subsequent magnetic layer (recording layer). The metal and oxide phases in the composite thin films are immiscible. The final microstructure of the interlayer depends on factors, such as, sputtering pressure, oxide species, oxide volume fraction, thickness, alloy composition, temperature etc. Moreover, it has been found that the microstructure of the composite thin films is affected mostly by two important factors---oxide volume fraction and sputtering pressure. The latter affects grain size and grain segregation through surface-diffusion modification and the self-shadowing effect. The composite Ru + oxide interlayers were found to have various microstructures under various sputtering conditions. Four characteristic microstructure zones can be identified as a function of oxide volume fraction and sputtering pressure---"percolated" (A), "maze" (T), "granular" (B) and "embedded" (C), based on which, a new structural zone model (SZM) is established for composite thin films. The granular microstructure of zone B is of particular interest for recording media application. The grain size of interlayers is a strong function of pressure, oxide species and oxide volume fraction. Magnetic layers grown on top of these interlayers were found to be significantly affected by the interlayer microstructure. One-to-one grain epitaxial growth is very difficult to achieve when the grain size is too small. As a result, the magnetic properties of smaller grain size magnetic layers deteriorate due to poor growth. This presents a huge challenge to high areal density magnetic recording media. A novel approach of Ar-ion etched Ru seedlayer, which can improve epitaxy between interlayer and magnetic layer is proposed. This method produces interlayer thin films of: (1) smaller grain size and higher nucleation density due to both a rougher seedlayer surface and an oxide addition in the interlayer; (2) good (00.2) texture due to the growth on top of the low pressure deposited Ru seedlayer; (3) dome-shape grain morphology due to the high pressure deposition. Therefore, a significant Ru grain size reduction with enhanced granular morphology and improved grain-to-grain epitaxy with the magnetic layer was achieved. High resolution transmission electron microscopy (TEM) techniques, such as, electron energy loss spectroscopy (EELS), energy-filtered TEM (EFTEM), energy-dispersive X-ray spectroscopy (EDS) and mapping, and high angle annular dark field (HAADF) imaging have been utilized to investigate elemental distribution and grain morphology in composite magnetic thin films of different grain sizes. An oxygen-rich grain shell of about 0.5 ˜ 1 nm thickness is often observed for most media with different grain sizes. Reducing the grain size increases surface to volume ratio. With more surface area, smaller grains are more vulnerable to oxidization, resulting in even greater influence of the oxide on the magnetic properties of the grains.

NEXUS - Resilient Intelligent Middleware

NASA Astrophysics Data System (ADS)

Kaveh, N.; Hercock, R. Ghanea

Service-oriented computing, a composition of distributed-object computing, component-based, and Web-based concepts, is becoming the widespread choice for developing dynamic heterogeneous software assets available as services across a network. One of the major strengths of service-oriented technologies is the high abstraction layer and large granularity level at which software assets are viewed compared to traditional object-oriented technologies. Collaboration through encapsulated and separately defined service interfaces creates a service-oriented environment, whereby multiple services can be linked together through their interfaces to compose a functional system. This approach enables better integration of legacy and non-legacy services, via wrapper interfaces, and allows for service composition at a more abstract level especially in cases such as vertical market stacks. The heterogeneous nature of service-oriented technologies and the granularity of their software components makes them a suitable computing model in the pervasive domain.

Antimicrobial-Coated Granules for Disinfecting Water

NASA Technical Reports Server (NTRS)

Akse, James R.; Holtsnider, John T.; Kliestik, Helen

2011-01-01

Methods of preparing antimicrobialcoated granules for disinfecting flowing potable water have been developed. Like the methods reported in the immediately preceding article, these methods involve chemical preparation of substrate surfaces (in this case, the surfaces of granules) to enable attachment of antimicrobial molecules to the surfaces via covalent bonds. A variety of granular materials have been coated with a variety of antimicrobial agents that include antibiotics, bacteriocins, enzymes, bactericides, and fungicides. When employed in packed beds in flowing water, these antimicrobial-coated granules have been proven effective against gram-positive bacteria, gram-negative bacteria, fungi, and viruses. Composite beds, consisting of multiple layers containing different granular antimicrobial media, have proven particularly effective against a broad spectrum of microorganisms. These media have also proven effective in enhancing or potentiating the biocidal effects of in-line iodinated resins and of very low levels of dissolved elemental iodine.

Large Scale Beam-Tests of the Silicon and Scintillator-SiPM Modules for the CMS High Granularity Calorimeter at the HL-LHC

NASA Astrophysics Data System (ADS)

Jain, Shilpi

The High Granularity Calorimeter (HGCAL) will replace the existing CMS endcap calorimeters during the High Luminosity run of the LHC (HL-LHC) era. The electromagnetic part, as well as the first layers of the hadronic part, foresees around 600 square metres of silicon sensors as the active material. The remainder of the HGCAL, in the lower radiation environment, will use plastic scintillators with on-tile silicon photomultiplier (SiPM) readout. Prototype hexagonal silicon modules, featuring a new ASIC (Skiroc2-CMS), together with a modified version of the scintillator-SiPM CALICE AHCAL, have been tested in beams at CERN. This setup represents a full slice through HGCAL. Results from MIP calibration, energy resolution, electromagnetic and hadronic shower-shapes are presented using electrons, pions and muons.

Rate of deoxygenation modulates rheologic behavior of sickle red blood cells at a given mean corpuscular hemoglobin concentration.

PubMed

Kaul, D K; Liu, X D

1999-01-01

Although the mean corpuscular hemoglobin concentration (MCHC) plays a dominant role in the rheologic behavior of deoxygenated density-defined sickle red blood cells (SS RBCs), previous studies have not explored the relationship between the rate of deoxygenation and the bulk viscosity of SS RBCs at a given MCHC. In the present study, we have subjected density-defined SS classes (i.e., medium-density SS4 and dense SS5 discocytes) to varying deoxygenation rates. This approach has allowed us to minimize the effects of SS RBC heterogeneity and investigate the effect of deoxygenation rates at a given MCHC. The results show that the percentages of granular cells, classic sickle cells and holly leaf forms in deoxygenated samples are significantly influenced by the rate of deoxygenation and the MCHC of a given discocyte subpopulation. Increasing the deoxygenation rate using high K+ medium (pH 6.8), results in a greater percentage of granular cells in SS4 suspensions, accompanied by a pronounced increase in the bulk viscosity of these cells compared with gradually deoxygenated samples (mainly classic sickle cells and holly leaf forms). The effect of MCHC becomes apparent when SS5 dense cells are subjected to varying deoxygenation rates. At a given deoxygenation rate, SS5 dense discocytes show a greater increase in the percentage of granular cells than that observed for SS4 RBCs. Also, at a given deoxygenation rate, SS5 suspensions exhibit a higher viscosity than SS4 suspensions with fast deoxygenation resulting in maximal increase in viscosity. Although MCHC is the main determinant of SS RBC rheologic behavior, these studies demonstrate for the first time that at a given MCHC, the rate of deoxygenation (hence HbS polymerization rates) further modulates the rheologic behavior of SS RBCs. Thus, both MCHC and the deoxygenation rate may contribute to microcirculatory flow behavior of SS RBCs.

Layered Systems Engineering Engines

NASA Technical Reports Server (NTRS)

Breidenthal, Julian C.; Overman, Marvin J.

2009-01-01

A notation is described for depicting the relationships between multiple, contemporaneous systems engineering efforts undertaken within a multi-layer system-of-systems hierarchy. We combined the concepts of remoteness of activity from the end customer, depiction of activity on a timeline, and data flow to create a new kind of diagram which we call a "Layered Vee Diagram." This notation is an advance over previous notations because it is able to be simultaneously precise about activity, level of granularity, product exchanges, and timing; these advances provide systems engineering managers a significantly improved ability to express and understand the relationships between many systems engineering efforts. Using the new notation, we obtain a key insight into the relationship between project duration and the strategy selected for chaining the systems engineering effort between layers, as well as insights into the costs, opportunities, and risks associated with alternate chaining strategies.

Laser readable thermoluminescent radiation dosimeters and methods for producing thereof

DOEpatents

Braunlich, P.F.; Tetzlaff, W.

1989-04-25

Thin layer thermoluminescent radiation dosimeters for use in laser readable dosimetry systems, and methods of fabricating such thin layer dosimeters are disclosed. The thin layer thermoluminescent radiation dosimeters include a thin substrate made from glass or other inorganic materials capable of withstanding high temperatures and high heating rates. A thin layer of a thermoluminescent phosphor material is heat bonded to the substrate using an inorganic binder such as glass. The dosimeters can be mounted in frames and cases for ease in handling. Methods of the invention include mixing a suitable phosphor composition and binder, both being in particulate or granular form. The mixture is then deposited onto a substrate such as by using mask printing techniques. The dosimeters are thereafter heated to fuse and bond the binder and phosphor to the substrate. 34 figs.

Gamma delta T-cell large granular lymphocyte lymphoma in a dog.

PubMed

Ortiz, Ana Liza; Carvalho, Sofia; Leo, Chiara; Riondato, Fulvio; Archer, Joy; Cian, Francesco

2015-09-01

A 2-year and 6-month-old female neutered Labrador Retriever with Horner syndrome, megaesophagus, and a mediastinal mass was referred to the Queen Mother Hospital for Animals of the Royal Veterinary College. A large granular lymphocyte (LGL) lymphoma was diagnosed on cytology; flow cytometric analysis revealed a γδ T-cell phenotype (CD3+, CD5+, CD45+, TCRγδ+, CD4-, CD8-, CD34-, CD21-). Chemotherapy was started with a combination of lomustine, vincristine, procarbazine, and prednisolone, followed by bleyomicin. Euthanasia was elected by the owners, due to progressive deterioration and lack of quality of life, 28 days after diagnosis. This is the first cytologic and immunophenotypic characterization of a canine γδ T-cell lymphoma with LGL morphology and probably of mediastinal origin. The role of chemotherapy in delaying the disease progression remains unknown. © 2015 American Society for Veterinary Clinical Pathology.

Granular cells in the presence of magnetic field

NASA Astrophysics Data System (ADS)

Jurčák, J.; Lemmerer, B.; van Noort, M.

2017-10-01

We present a statistical study of the dependencies of the shapes and sizes of the photospheric convective cells on the magnetic field properties. This analysis is based on a 2.5 hour long SST observations of active region NOAA 11768. We have blue continuum images taken with a cadence of 5.6 sec that are used for segmentation of individual granules and 270 maps of spectropolarimetric CRISP data allowing us to determine the properties of the magnetic field along with the line-of-sight velocities. The sizes and shapes of the granular cells are dependent on the the magnetic field strength, where the granules tend to be smaller in regions with stronger magnetic field. In the presence of highly inclined magnetic fields, the eccentricity of granules is high and we do not observe symmetric granules in these regions. The mean up-flow velocities in granules as well as the granules intensities decrease with increasing magnetic field strength.

Multiple granular cell tumors with metachronous occurrence in tongue and vulva. Clinicopathological and immunohistochemical study

PubMed Central

Vera-Sirera, Beatriz; Zabala, Pablo; Aviño-Mira, Carlos; Vera-Sempere, Francisco J.

2014-01-01

Granular cell tumor (GCT) usually occurs as a single tumor, although sometimes multiple lesions can occur. In present report we analyze the clinicopathological and immunohistochemical features of a multiple GCT involving the tongue of a 14-year-old girl, with no other abnormalities, with a metachronous occurrence of a second GCT in vulva, after a period of 10 years. Both tumors revealed S-100, vimentin and CD57 positivity. In addition, over expression of calretinin was observed in tumor cells located in the vicinity of pseudoepitheliomatous hyperplasia (PEH) of the tongue. Tumor vasculature situated close to the PEH showed marked CD105 reactivity, data not described so far, suggesting an interaction between PEH cells and underlying stroma, since GCT completely lacks CD105 vessels. Our study emphasizes that patients with GCT, especially young patients, should be followed long-term, looking for multiple tumors or other abnormalities suggestive of a systemic syndrome, given the associations described in multiple GCT. PMID:25949003

Locating the origin of stick slip instabilities in sheared granular layers

NASA Astrophysics Data System (ADS)

Korkolis, Evangelos; Niemeijer, André

2017-04-01

Acoustic emission (AE) monitoring is a non-invasive technique widely used to evaluate the state of materials and structures. We have developed a system that can locate the source of AE events associated with unstable sliding (stick-slip) of sheared granular layers during laboratory friction experiments. Our aim is to map the spatial distribution of energy release due to permanent microstructural changes, using AE source locations as proxies. This will allow us to determine the distribution of applied work in a granular medium, which will be useful in developing constitutive laws that describe the frictional behavior of such materials. The AE monitoring system is installed on a rotary shear apparatus. This type of apparatus is used to investigate the micromechanical processes responsible for the macroscopic frictional behavior of granular materials at large shear displacements. Two arrays of 8 piezoelectric sensors each are installed into the ring-shaped steel pistons that confine our samples. The sensors are connected to a high-speed, multichannel oscilloscope that can record full waveforms. The apparatus is also equipped with a system that continuously records normal and lateral (shear) loads and displacements, as well as pore fluid pressure. Thus, we can calculate the frictional and volumetric response of our granular aggregates, as well as the location of AE sources. Here, we report on the results of room temperature experiments on granular aggregates consisting of glass beads or segregated mixtures of glass beads and calcite, at up to 5 MPa normal stress and sliding velocities between 1 and 100 μm/s. Under these conditions, glass beads exhibit unstable sliding behavior accompanied by significant AE activity, whereas calcite exhibits stable sliding and produces no AEs. We recorded a range of unstable sliding behaviors, from fast, regular stick slip at high normal stress (> 4 MPa) and sliding velocities below 20 μm/s, to irregular stick slip at low normal stress or sliding velocities above 20 μm/s. We calculated the source location of each AE associated with significant stress drops (slip events). A very prominent feature, particularly among the large shear displacement experiments, was the development of regions that sustained increased AE activity. Some of these regions remained fixed in space, whereas others kept migrating with increasing shear displacement. We observed that for an arbitrarily small number of consecutive slip events, their associated AEs did not necessarily nucleate in the same region. We believe that the calculated AE source locations reveal the sites where load-bearing microstructures, known as force chains, begin to fail, leading to slip instabilities. The existence of regions of increased AE activity suggests that triggering of force chain failure is controlled to some extent by the loading conditions imposed on the sample by the machine, but may also indicate the lasting influence of previous particle re-organization events on the particles populating these regions.

Orthopyroxene oikocrysts in the MG1 chromitite layer of the Bushveld Complex: implications for cumulate formation and recrystallisation

NASA Astrophysics Data System (ADS)

Kaufmann, Felix E. D.; Vukmanovic, Zoja; Holness, Marian B.; Hecht, Lutz

2018-02-01

Two typical mineral textures of the MG 1 chromitite of the Bushveld Complex, South Africa, were observed; one characterised by abundant orthopyroxene oikocrysts, and the other by coarse-grained granular chromitite with only minor amounts of interstitial material. Oikocrysts form elongate clusters of several crystals aligned parallel to the layering, and typically have subhedral, almost chromite-free, core zones containing remnants of olivine. The core zones are surrounded by poikilitic aureoles overgrowing euhedral to subhedral chromite chadacrysts. Chromite grains show no preferred crystal orientation, whereas orthopyroxene grains forming clusters commonly share the same crystallographic orientation. Oikocryst core zones have lower Mg# and higher concentrations of incompatible trace elements compared to their poikilitic aureoles. Core zones are relatively enriched in REE compared to a postulated parental magma (B1) and did not crystallise in equilibrium with the surrounding minerals, whereas the composition of the poikilitic orthopyroxene is consistent with growth from the B1 magma. These observations cannot be explained by the classic cumulus and post-cumulus models of oikocryst formation. Instead, we suggest that the oikocryst core zones in the MG1 chromitite layer formed by peritectic replacement of olivine primocrysts by reaction with an upwards-percolating melt enriched in incompatible trace elements. Poikilitic overgrowth on oikocryst core zones occurred in equilibrium with a basaltic melt of B1 composition near the magma-crystal mush interface. Finally, adcumulus crystallisation followed by grain growth resulted in the surrounding granular chromitite.

Spatiotemporal expression of MANF in the developing rat brain.

PubMed

Wang, Haiping; Ke, Zunji; Alimov, Alexander; Xu, Mei; Frank, Jacqueline A; Fang, Shengyun; Luo, Jia

2014-01-01

Mesencephalic astrocyte-derived neurotrophic factor (MANF) is an evolutionarily conserved neurotrophic factor which exhibited neuroprotective properties. Recent studies suggested that MANF may play a role in the neural development of Drosophila and zebra fishes. In this study, we investigated the spatiotemporal expression of MANF in the brain of postnatal and adult rats. MANF expression appeared wide spread and mainly localized in neurons. In the cerebral cortex, neurons in layer IV and VI displayed particularly strong MANF immunoreactivity. In the hippocampus, intensive MANF expression was observed throughout the subfields of Cornu Amonis (CA1, CA2, and CA3) and the granular layer of the dentate gyrus (DG). In the substantia nigra, high MANF expression was shown in the substantia nigra pars compacta (SNpc). In the thalamus, the anterodorsal thalamic nucleus (ADTN) exhibited the highest MANF immunoreactivity. In the hypothalamus, intensive MANF immunoreactivity was shown in the supraoptic nucleus (SON) and tuberomammillary nucleus (TMN). In the cerebellum, MANF was localized in the external germinal layer (EGL), Purkinje cell layer (PCL), internal granule layer (IGL) and the deep cerebellar nuclei (DCN). We examined the developmental expression of MANF on postnatal day (PD) 3, 5, 7, 9, 15, 21, 30 and adulthood. In general, the levels of MANF were high in the early PDs (PD3 and PD5), and declined gradually as the brain matured; MANF expression in the adult brain was the lowest among all time points examined. However, in some structures, such as PCL, IGL, SON, TMN and locus coeruleus (LC), high expression of MANF sustained throughout the postnatal period and persisted into adulthood. Our results indicated that MANF was developmentally regulated and may play a role in the maturation of the central nervous system (CNS).

Spatiotemporal Expression of MANF in the Developing Rat Brain

PubMed Central

Wang, Haiping; Ke, Zunji; Alimov, Alexander; Xu, Mei; Frank, Jacqueline A.; Fang, Shengyun; Luo, Jia

2014-01-01

Mesencephalic astrocyte-derived neurotrophic factor (MANF) is an evolutionarily conserved neurotrophic factor which exhibited neuroprotective properties. Recent studies suggested that MANF may play a role in the neural development of Drosophila and zebra fishes. In this study, we investigated the spatiotemporal expression of MANF in the brain of postnatal and adult rats. MANF expression appeared wide spread and mainly localized in neurons. In the cerebral cortex, neurons in layer IV and VI displayed particularly strong MANF immunoreactivity. In the hippocampus, intensive MANF expression was observed throughout the subfields of Cornu Amonis (CA1, CA2, and CA3) and the granular layer of the dentate gyrus (DG). In the substantia nigra, high MANF expression was shown in the substantia nigra pars compacta (SNpc). In the thalamus, the anterodorsal thalamic nucleus (ADTN) exhibited the highest MANF immunoreactivity. In the hypothalamus, intensive MANF immunoreactivity was shown in the supraoptic nucleus (SON) and tuberomammillary nucleus (TMN). In the cerebellum, MANF was localized in the external germinal layer (EGL), Purkinje cell layer (PCL), internal granule layer (IGL) and the deep cerebellar nuclei (DCN). We examined the developmental expression of MANF on postnatal day (PD) 3, 5, 7, 9, 15, 21, 30 and adulthood. In general, the levels of MANF were high in the early PDs (PD3 and PD5), and declined gradually as the brain matured; MANF expression in the adult brain was the lowest among all time points examined. However, in some structures, such as PCL, IGL, SON, TMN and locus coeruleus (LC), high expression of MANF sustained throughout the postnatal period and persisted into adulthood. Our results indicated that MANF was developmentally regulated and may play a role in the maturation of the central nervous system (CNS). PMID:24587361

Comparison of the influence of two models of mild stress on hippocampal brain-derived neurotrophin factor (BDNF) immunoreactivity in old age rats.

PubMed

Badowska-Szalewska, Ewa; Ludkiewicz, Beata; Krawczyk, Rafał; Melka, Natalia; Moryś, Janusz

2017-01-01

The way hippocampal neurons function during stress in old age (critical times of life) is dependent on brain derived neurotrophin factor (BDNF). This study examined the influence of acute and chronic forced swim (FS) or high-light open field (HL‑OF) stimulation on the density of BDNF immunoreactive (ir) neurons in the hippocampal pyramidal layers of CA1, CA2, CA3 regions and the granular layer of dentate gyrus (DG) in old (postnatal day 720; P720) Wistar Han rats. Our data showed that in comparison with non-stressed rats, acute FS caused a significant increase in the density of BDNF-ir neurons in CA2 and CA3, while acute HL-OF led to an increase in this factor in all hippocampal subfields with the exception of DG. However, the density of BDNF-ir cells remained unchanged after exposure to chronic FS or HL‑OF in the hippocampal regions in relation to the control rats. These results indicate that acute FS or HL-OF proved to be a stressor that induces an increase in the density of BDNF-ir pyramidal neurons, which was probably connected with up-regulation of HPA axis activity and short‑time memory processing of the stressful situation. Moreover, as far as the influence on BDNF-ir cells in hippocampus is concerned, chronic FS or HL-OF was not an aggravating factor for rats in the ontogenetic periods studied.

The occurrence of macro- and mesoscopic methane hydrate in the eastern margin of Japan Sea

NASA Astrophysics Data System (ADS)

Matsumoto, R.; Kakuwa, Y.; Tanahashi, M.; Hiruta, A.

2016-12-01

Shallow methane hydrate is known to occur in muddy sediments that were deposited in the eastern margin of Japan Sea. In such settings, the hydrate occurs just below the seabed or is exposed directly on the seabed. Its presence is quite different from the pore-filling type of hydrate typically found in sandstone of the Pacific Ocean side of the Japanese islands. This presentation focuses on categorizing the distribution of gas hydrate in Japan Sea which, until recently, has been poorly understood. Macroscopic occurrence: Numerous gas chimney structures, which are characterized by an acoustic blanking on sub-bottom profiler images, have been discovered in the eastern margin of Japan Sea. We carried out seafloor drilling at several topographic highs that showed gas chimney structures. The results confirm that, while methane hydrate does not occur in the well-stratified part of SBP images, it does occur uniquely in the gas chimney structure-bearing mounds and pockmarks. Several horizons of methane hydrate-concentrated layers are identified by our LWD data and are traceable over lateral distances of as much as a kilometer.. In another case, the methane hydrate-concentrated layers occur stratigraphically in a regular manner with methane-derived carbonate nodules. We interpret the second case as one in which methane gas was supplied by regularly repeated movements of active fault(s). Mesoscopic occurrence: Methane hydrate is classified into 5 types that are readily observable in drilled cores: granular, nodular, platy, veiny and massive. The granular type is common over shallower intervals, while platy and veiny types are more common in the deeper intervals. Nevertheless, a significant fraction of the granular type may have possibly originated from the destruction and dissociation of other types during drilling and recovery. The massive type hydrate that characterizes highly-concentrated layers transitions to other types laterally as methane hydrate becomes poorly concentrated. This study was conducted under the commission from AIST as a part of the methane hydrate research project funded by METI (the Ministry of Economy, Trade and Industry, Japan).

Tissue distribution and subcellular localizations determine in vivo functional relationship among prostasin, matriptase, HAI-1, and HAI-2 in human skin.

PubMed

Lee, Shiao-Pieng; Kao, Chen-Yu; Chang, Shun-Cheng; Chiu, Yi-Lin; Chen, Yen-Ju; Chen, Ming-Hsing G; Chang, Chun-Chia; Lin, Yu-Wen; Chiang, Chien-Ping; Wang, Jehng-Kang; Lin, Chen-Yong; Johnson, Michael D

2018-01-01

The membrane-bound serine proteases prostasin and matriptase and the Kunitz-type protease inhibitors HAI-1 and HAI-2 are all expressed in human skin and may form a tightly regulated proteolysis network, contributing to skin pathophysiology. Evidence from other systems, however, suggests that the relationship between matriptase and prostasin and between the proteases and the inhibitors can be context-dependent. In this study the in vivo zymogen activation and protease inhibition status of matriptase and prostasin were investigated in the human skin. Immunohistochemistry detected high levels of activated prostasin in the granular layer, but only low levels of activated matriptase restricted to the basal layer. Immunoblot analysis of foreskin lysates confirmed this in vivo zymogen activation status and further revealed that HAI-1 but not HAI-2 is the prominent inhibitor for prostasin and matriptase in skin. The zymogen activation status and location of the proteases does not support a close functional relation between matriptase and prostasin in the human skin. The limited role for HAI-2 in the inhibition of matriptase and prostasin is the result of its primarily intracellular localization in basal and spinous layer keratinocytes, which probably prevents the Kunitz inhibitor from interacting with active prostasin or matriptase. In contrast, the cell surface expression of HAI-1 in all viable epidermal layers renders it an effective regulator for matriptase and prostasin. Collectively, our study suggests the importance of tissue distribution and subcellular localization in the functional relationship between proteases and protease inhibitors.

A Nonribosomal Landscape in the Nucleolus Revealed by the Stem Cell Protein Nucleostemin

PubMed Central

Politz, Joan C. Ritland; Polena, Ilvin; Trask, Ian; Bazett-Jones, David P.; Pederson, Thoru

2005-01-01

Nucleostemin is a p53-interactive cell cycle progression factor that shuttles between the nucleolus and nucleoplasm, but it has no known involvement in ribosome synthesis. We found the dynamic properties of nucleostemin differed strikingly from fibrillarin (a protein directly involved in rRNA processing) both in response to rRNA transcription inhibition and in the schedule of reentry into daughter nuclei and the nucleolus during late telophase/early G1. Furthermore, nucleostemin was excluded from the nucleolar domains in which ribosomes are born—the fibrillar centers and dense fibrillar component. Instead it was concentrated in rRNA-deficient sites within the nucleolar granular component. This finding suggests that the nucleolus may be more subcompartmentalized than previously thought. In support of this concept, electron spectroscopic imaging studies of the nitrogen and phosphorus distribution in the nucleolar granular component revealed regions that are very rich in protein and yet devoid of nucleic acid. Together, these results suggest that the ultrastructural texture of the nucleolar granular component represents not only ribosomal particles but also RNA-free zones populated by proteins or protein complexes that likely serve other functions. PMID:15857956

Immune gene expression for diverse haemocytes derived from pacific white shrimp, Litopenaeus vannamei.

PubMed

Yang, Chih-Chiu; Lu, Chung-Lun; Chen, Sherwin; Liao, Wen-Liang; Chen, Shiu-Nan

2015-05-01

In this study, diverse haemocytes from Pacific white shrimp Litopenaeus vannamei were spread by flow cytometer sorting system. Using the two commonly flow cytometric parameters FSC and SSC, the haemocytes could be divided into three populations. Microscopy observation of L. vannamei haemocytes in anticoagulant buffer revealed three morphologically distinct cell types designated as granular cell, hyaline cell and semigranular cell. Immune genes, which includes prophenoloxidase (proPO), lipopolysaccharide-β-glucan binding protein (LGBP), peroxinectin, crustin, lysozyme, penaeid-3a and transglutaminase (TGase), expressed from different haemocyte were analysed by quantitative real time PCR (qPCR). Results from the mRNA expression was estimated by relative level of each gene to β-actin gene. Finally, the seven genes could be grouped by their dominant expression sites. ProPO, LGBP and peroxinectin were highly expressed in granular cells, while LGBP, crustin, lysozyme and P-3a were highly expressed in semigranular cells and TGase was highly expressed in hyaline cells. In this study, L. vannamei haemocytes were firstly grouped into three different types and the immune related genes expression in grouped haemocytes were estimated. Copyright © 2015 Elsevier Ltd. All rights reserved.

Ten cases of severe oral lichen planus showing granular C3 deposition in oral mucosal basement membrane zone.

PubMed

Hashimoto, Takashi; Fukuda, Aoi; Himejima, Akio; Morita, Shosuke; Tsuruta, Daisuke; Koga, Hiroshi; Krol, Rafal P; Ishii, Norito

2015-01-01

Oral lichen planus (OLP) may show depositions of immunoglobulins and complement components in oral mucosal basement membrane zone (BMZ) in direct immunofluorescence, although these finding are not frequently seen. We collected and examined ten cases of severe OLP showing granular C3 deposition in BMZ. In addition to clinical, histopathological and direct immunofluorescence assessments, we performed various immune-serological tests, including indirect immunofluorescence of normal human skin and 1M NaCl-split skin, immunoblotting of normal human epidermal and dermal extracts, recombinant proteins of BP180 NC16a and C-terminal domains, concentrated culture supernatant of HaCaT cells and purified human laminin-332, and enzyme-linked immunosorbent assays for BP230 and BP180. Direct immunofluorescence showed C3 deposition in BMZ exclusively of granular pattern in 7 cases and of both granular and linear patterns in 3 cases. The 10 cases showed no positive reactivity for either IgG or IgA antibodies in any immuno-serological tests. Detailed analyses of clinical, histopathological and immunological findings revealed striking female prevalence, although other parameters were in general characteristic of OLP. Granular C3 deposition in oral BMZ may be one of the characteristic features of severe OLP, although mechanisms for C3 deposition and its pathogenic role in OLP are currently unknown.

The Quantified Characterization Method of the Micro-Macro Contacts of Three-Dimensional Granular Materials on the Basis of Graph Theory.

PubMed

Guan, Yanpeng; Wang, Enzhi; Liu, Xiaoli; Wang, Sijing; Luan, Hebing

2017-08-03

We have attempted a multiscale and quantified characterization method of the contact in three-dimensional granular material made of spherical particles, particularly in cemented granular material. Particle contact is defined as a type of surface contact with voids in its surroundings, rather than a point contact. Macro contact is a particle contact set satisfying the restrictive condition of a two-dimensional manifold with a boundary. On the basis of graph theory, two dual geometrical systems are abstracted from the granular pack. The face and the face set, which satisfies the two-dimensional manifold with a boundary in the solid cell system, are extracted to characterize the particle contact and the macro contact, respectively. This characterization method is utilized to improve the post-processing in DEM (Discrete Element Method) from a micro perspective to describe the macro effect of the cemented granular material made of spherical particles. Since the crack has the same shape as its corresponding contact, this method is adopted to characterize the crack and realize its visualization. The integral failure route of the sample can be determined by a graph theory algorithm. The contact force is assigned to the weight value of the face characterizing the particle contact. Since the force vectors can be added, the macro contact force can be solved by adding the weight of its corresponding faces.

The kinetics of dolomite reaction rim growth under isostatic and non-isostatic pressure conditions

NASA Astrophysics Data System (ADS)

Helpa, V.; Rybacki, E.; Morales, L. G.; Abart, R.; Dresen, G. H.

2013-12-01

During burial and exhumation, rocks are simultaneously exposed to metamorphic reactions and tectonic stresses. Therefore, the reaction rate of newly formed minerals may depend on chemical and mechanical driving forces. Here, we investigate the reaction kinetics of dolomite (CaMg[CO3]2) rim growth by solid-state reactions experiments on oriented calcite (CaCO3) and magnesite (MgCO3) single crystals under isostatic and non-isostatic pressure conditions. Cylindrical samples of 3-5 mm length and 7 mm diameter were drilled and polished perpendicular to the rhombohedral cleavage planes of natural clear crystals. The tests were performed using a Paterson-type deformation apparatus at P = 400 MPa confining pressure, temperatures, T, between 750 and 850°C, and reaction durations, t, of 2 - 146 h to calculate the kinetic parameters of dolomite rim growth under isostatic stress conditions. For non-isostatic reaction experiments we applied in addition differential stresses, σ, up to 40 MPa perpendicular to the contact interface at T = 750°C for 4 - 171 h duration, initiating minor inelastic deformation of calcite. The thickness of the resulting dolomite reaction rims increases linearly with the square root of time, indicating a diffusion-controlled reaction. The rims consist of two different textural domains. Granular dolomite grains (≈ 2 -5 μm grain size) form next to calcite and elongated palisade-shaped grains (1-6 μm diameter) grow perpendicular to the magnesite interface. Texture measurements with the electron backscatter diffraction technique indicate that the orientations of dolomite grains are mainly influenced by the orientation of the calcite educt crystal, in particular in the granular rim. To some extent, the texture of dolomite palisades is also influenced by the orientation of magnesite. The thickness of the two individual layers increases with temperature. At 400 MPa isostatic pressure, T = 750°C and t = 29 hours, a 5 μm thick granular dolomite layer and a 7 μm thick palisade-shaped layer evolve. At similar conditions and a differential stress of 30 MPa, the rim thickness remains similar; consequently the effect of non-isostatic stress on dolomite rim growth is negligible. Platinum markers show that the initial calcite-magnesite interface is located between granular and palisade-forming dolomite, indicating that rim growth occurs by counter diffusion of MgO and CaO. Diffusion of MgO across the dolomite reaction rim into calcite forms additionally magnesio-calcite grains with diameters of ≈ 13 - 46 μm, depending on the experimental conditions and increasing with increasing distance to the dolomite boundary. At T = 750°C, t = 29 hours, the thickness of the magnesio-calcite layer is 32 μm (isostatic) - 35 μm (σ = 30 MPa). The experiments indicate that solid-state reaction rim growth of dolomite between calcite and magnesite is primarily controlled by diffusion of MgO and CaO, forming layers with different microstructures during growth into the educt phases. The kinetics of the reaction in the carbonate system are not significantly changed by differential stresses up to 40 MPa. We suggest that volume diffusion is the dominant transport mechanism, which is presumably less affected by non-isostatic stresses than grain boundary diffusion.

Pneumatic fractures in Confined Granular Media

NASA Astrophysics Data System (ADS)

Eriksen, Fredrik K.; Toussaint, Renaud; Jørgen Måløy, Knut; Grude Flekkøy, Eirik; Turkaya, Semih

2016-04-01

We will present our ongoing study of the patterns formed when air flows into a dry, non-cohesive porous medium confined in a horizontal Hele-Shaw cell. This is an optically transparent system consisting of two glass plates separated by 0.5 to 1 mm, containing a packing of dry 80 micron beads in between. The cell is rectangular and has an air-permeable boundary (blocking beads) at one short edge, while the other three edges are completely sealed. The granular medium is loosely packed against the semi-permeable boundary and fills about 80 % of the cell volume. This leaves an empty region at the sealed side, where an inlet allows us to set and maintain the air at a constant overpressure (0.1 - 2 bar). For the air trapped inside the cell to relax its overpressure it has to move through the deformable granular medium. Depending on the applied overpressure and initial density of the medium, we observe a range of different behaviors such as seepage through the pore-network with or without an initial compaction of the solid, formation of low density bubbles with rearrangement of particles, granular fingering/fracturing, and erosion inside formed channels/fractures. The experiments are recorded with a high-speed camera at a framerate of 1000 images/s and a resolution of 1024x1024 pixels. We use various image processing techniques to characterize the evolution of the air invasion patterns and the deformations in the surrounding material. The experiments are similar to deformation processes in porous media which are driven by pore fluid overpressure, such as mud volcanoes and hydraulic or pneumatic (gas-induced) fracturing, and the motivation is to increase the understanding of such processes by optical observations. In addition, this setup is an experimental version of the numerical models analyzed by Niebling et al. [1,2], and is useful for comparison with their results. In a directly related project [3], acoustic emissions from the cell plate are recorded during experiments, where we aim to localize acoustic events and correlate them with the optical observations. [1] Niebling M.J., Toussaint R., Flekkøy E.G. and Måløy K.J. (2012) Dynamic aerofracture of dense granular packings. Phys. Rev. E86, 061315. doi:10.1103/PhysRevE.86.061315 [2] Niebling M.J., Toussaint R., Flekkøy E.G. and Måløy K.J. (2012) Numerical studies of aerofractures in porous media. Rev. Cub. Fis. 29, 1E66 [3] Turkaya S., Toussaint R., Eriksen F.K., Zecevic M., Daniel G., Flekkøy E.G. and Måløy K.J. (2015)Bridging aero-fracture evolution with the characteristics of the acoustic emissions in a porous medium. Front. Phys. 3:70. doi: 10.3389/fphy.2015.00070

Direct Visualization of the Outer Membrane of Mycobacteria and Corynebacteria in Their Native State▿ †

PubMed Central

Zuber, Benoît; Chami, Mohamed; Houssin, Christine; Dubochet, Jacques; Griffiths, Gareth; Daffé, Mamadou

2008-01-01

The cell envelope of mycobacteria, which include the causative agents of tuberculosis and leprosy, is crucial for their success as pathogens. Despite a continued strong emphasis on identifying the multiple chemical components of this envelope, it has proven difficult to combine its components into a comprehensive structural model, primarily because the available ultrastructural data rely on conventional electron microscopy embedding and sectioning, which are known to induce artifacts. The existence of an outer membrane bilayer has long been postulated but has never been directly observed by electron microscopy of ultrathin sections. Here we have used cryo-electron microscopy of vitreous sections (CEMOVIS) to perform a detailed ultrastructural analysis of three species belonging to the Corynebacterineae suborder, namely, Mycobacterium bovis BCG, Mycobacterium smegmatis, and Corynebacterium glutamicum, in their native state. We provide new information that accurately describes the different layers of the mycobacterial cell envelope and challenges current models of the organization of its components. We show a direct visualization of an outer membrane, analogous to that found in gram-negative bacteria, in the three bacterial species examined. Furthermore, we demonstrate that mycolic acids, the hallmark of mycobacteria and related genera, are essential for the formation of this outer membrane. In addition, a granular layer and a low-density zone typifying the periplasmic space of gram-positive bacteria are apparent in CEMOVIS images of mycobacteria and corynebacteria. Based on our observations, a model of the organization of the lipids in the outer membrane is proposed. The architecture we describe should serve as a reference for future studies to relate the structure of the mycobacterial cell envelope to its function. PMID:18567661

Direct visualization of the outer membrane of mycobacteria and corynebacteria in their native state.

PubMed

Zuber, Benoît; Chami, Mohamed; Houssin, Christine; Dubochet, Jacques; Griffiths, Gareth; Daffé, Mamadou

2008-08-01

The cell envelope of mycobacteria, which include the causative agents of tuberculosis and leprosy, is crucial for their success as pathogens. Despite a continued strong emphasis on identifying the multiple chemical components of this envelope, it has proven difficult to combine its components into a comprehensive structural model, primarily because the available ultrastructural data rely on conventional electron microscopy embedding and sectioning, which are known to induce artifacts. The existence of an outer membrane bilayer has long been postulated but has never been directly observed by electron microscopy of ultrathin sections. Here we have used cryo-electron microscopy of vitreous sections (CEMOVIS) to perform a detailed ultrastructural analysis of three species belonging to the Corynebacterineae suborder, namely, Mycobacterium bovis BCG, Mycobacterium smegmatis, and Corynebacterium glutamicum, in their native state. We provide new information that accurately describes the different layers of the mycobacterial cell envelope and challenges current models of the organization of its components. We show a direct visualization of an outer membrane, analogous to that found in gram-negative bacteria, in the three bacterial species examined. Furthermore, we demonstrate that mycolic acids, the hallmark of mycobacteria and related genera, are essential for the formation of this outer membrane. In addition, a granular layer and a low-density zone typifying the periplasmic space of gram-positive bacteria are apparent in CEMOVIS images of mycobacteria and corynebacteria. Based on our observations, a model of the organization of the lipids in the outer membrane is proposed. The architecture we describe should serve as a reference for future studies to relate the structure of the mycobacterial cell envelope to its function.

Hydroxyurea Treatment and Development of the Rat Cerebellum: Effects on the Neurogenetic Profiles and Settled Patterns of Purkinje Cells and Deep Cerebellar Nuclei Neurons.

PubMed

Martí, Joaquín; Santa-Cruz, M C; Serra, Roger; Hervás, José P

2016-11-01

The current paper analyzes the development of the male and female rat cerebellum exposed to hydroxyurea (HU) (300 or 600 mg/kg) as embryo and collected at postnatal day 90. Our study reveals that the administration of this drug compromises neither the cytoarchitecture of the cerebellar cortex nor deep nuclei (DCN). However, in comparison with the saline group, we observed that several cerebellar parameters were lower in the HU injected groups. These parameters included area of the cerebellum, cerebellar cortex length, molecular layer area, Purkinje cell number, granule cell counts, internal granular layer, white matter and cerebellar nuclei areas, and number of deep cerebellar nuclei neurons. These features were larger in the rats injected with saline, smaller in those exposed to 300 mg/kg of HU and smallest in the group receiving 600 mg/kg of this agent. No sex differences in the effect of the HU were observed. In addition, we infer the neurogenetic timetables and the neurogenetic gradients of PCs and DCN neurons in rats exposed to either saline or HU as embryos. For this purpose, 5-bromo-2'-deoxyuridine was injected into pregnant rats previously administered with saline or HU. This thymidine analog was administered following a progressively delayed cumulative labeling method. The data presented here show that systematic differences exist in the pattern of neurogenesis and in the spatial location of cerebellar neurons between rats injected with saline or HU. No sex differences in the effect of the HU were observed. These findings have implications for the administration of this compound to women in gestation as the effects of HU on the development of the cerebellum might persist throughout their offsprings' life.

Motion Imagery and Robotics Application (MIRA): Standards-Based Robotics

NASA Technical Reports Server (NTRS)

Martinez, Lindolfo; Rich, Thomas; Lucord, Steven; Diegelman, Thomas; Mireles, James; Gonzalez, Pete

2012-01-01

This technology development originated from the need to assess the debris threat resulting from soil material erosion induced by landing spacecraft rocket plume impingement on extraterrestrial planetary surfaces. The impact of soil debris was observed to be highly detrimental during NASA s Apollo lunar missions and will pose a threat for any future landings on the Moon, Mars, and other exploration targets. The innovation developed under this program provides a simulation tool that combines modeling of the diverse disciplines of rocket plume impingement gas dynamics, granular soil material liberation, and soil debris particle kinetics into one unified simulation system. The Unified Flow Solver (UFS) developed by CFDRC enabled the efficient, seamless simulation of mixed continuum and rarefied rocket plume flow utilizing a novel direct numerical simulation technique of the Boltzmann gas dynamics equation. The characteristics of the soil granular material response and modeling of the erosion and liberation processes were enabled through novel first principle-based granular mechanics models developed by the University of Florida specifically for the highly irregularly shaped and cohesive lunar regolith material. These tools were integrated into a unique simulation system that accounts for all relevant physics aspects: (1) Modeling of spacecraft rocket plume impingement flow under lunar vacuum environment resulting in a mixed continuum and rarefied flow; (2) Modeling of lunar soil characteristics to capture soil-specific effects of particle size and shape composition, soil layer cohesion and granular flow physics; and (3) Accurate tracking of soil-borne debris particles beginning with aerodynamically driven motion inside the plume to purely ballistic motion in lunar far field conditions.

On the role of fluids in stick-slip dynamics of saturated granular fault gouge using a coupled computational fluid dynamics-discrete element approach: STICK-SLIP IN SATURATED FAULT GOUGE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dorostkar, Omid; Guyer, Robert A.; Johnson, Paul A.

The presence of fault gouge has considerable influence on slip properties of tectonic faults and the physics of earthquake rupture. The presence of fluids within faults also plays a significant role in faulting and earthquake processes. In this study, we present 3-D discrete element simulations of dry and fluid-saturated granular fault gouge and analyze the effect of fluids on stick-slip behavior. Fluid flow is modeled using computational fluid dynamics based on the Navier-Stokes equations for an incompressible fluid and modified to take into account the presence of particles. Analysis of a long time train of slip events shows that themore » (1) drop in shear stress, (2) compaction of granular layer, and (3) the kinetic energy release during slip all increase in magnitude in the presence of an incompressible fluid, compared to dry conditions. We also observe that on average, the recurrence interval between slip events is longer for fluid-saturated granular fault gouge compared to the dry case. This observation is consistent with the occurrence of larger events in the presence of fluid. It is found that the increase in kinetic energy during slip events for saturated conditions can be attributed to the increased fluid flow during slip. Finally, our observations emphasize the important role that fluid flow and fluid-particle interactions play in tectonic fault zones and show in particular how discrete element method (DEM) models can help understand the hydromechanical processes that dictate fault slip.« less

On the role of fluids in stick-slip dynamics of saturated granular fault gouge using a coupled computational fluid dynamics-discrete element approach: STICK-SLIP IN SATURATED FAULT GOUGE

DOE PAGES

Dorostkar, Omid; Guyer, Robert A.; Johnson, Paul A.; ...

2017-05-01

The presence of fault gouge has considerable influence on slip properties of tectonic faults and the physics of earthquake rupture. The presence of fluids within faults also plays a significant role in faulting and earthquake processes. In this study, we present 3-D discrete element simulations of dry and fluid-saturated granular fault gouge and analyze the effect of fluids on stick-slip behavior. Fluid flow is modeled using computational fluid dynamics based on the Navier-Stokes equations for an incompressible fluid and modified to take into account the presence of particles. Analysis of a long time train of slip events shows that themore » (1) drop in shear stress, (2) compaction of granular layer, and (3) the kinetic energy release during slip all increase in magnitude in the presence of an incompressible fluid, compared to dry conditions. We also observe that on average, the recurrence interval between slip events is longer for fluid-saturated granular fault gouge compared to the dry case. This observation is consistent with the occurrence of larger events in the presence of fluid. It is found that the increase in kinetic energy during slip events for saturated conditions can be attributed to the increased fluid flow during slip. Finally, our observations emphasize the important role that fluid flow and fluid-particle interactions play in tectonic fault zones and show in particular how discrete element method (DEM) models can help understand the hydromechanical processes that dictate fault slip.« less

Biomarkers of anhedonic-like behavior, antidepressant drug refraction, and stress resilience in a rat model of depression.

PubMed

Christensen, T; Bisgaard, C F; Wiborg, O

2011-11-24

The aim of the present study was to identify potential biomarkers for depression in the search for novel disease targets and treatment regimens. Furthermore, the study includes a search for biomarkers involved in treatment resistance and stress resilience in order to investigate mechanisms underlying antidepressant drug refraction and stress-coping strategies. Depression-related transcriptomic changes in gene expression profiles were investigated in laser-captured microdissected (LCM) rat hippocampal granular cell layers (GCL) using the chronic mild stress (CMS) rat model of depression and chronic administration of two selective serotonin reuptake inhibitors (SSRIs), escitalopram and sertraline. CMS rats were segregated into diverging groups according to behavioral readouts, and under stringent constraints, the associated differential gene regulations were analyzed. Accordingly, we identified four genes associated with recovery, two genes implicated in treatment resistance, and three genes involved in stress resilience. The identified genes associated with mechanisms of cellular plasticity, including signal transduction, cell proliferation, cell differentiation, and synaptic release. Hierarchical clustering analysis confirmed the subgroup segregation pattern in the CMS model. Thus antidepressant treatment refractors cluster with anhedonic-like rats, and, interestingly, stress-resilient rats cluster with rats undergoing antidepressant-mediated recovery from anhedonia, suggesting antidepressant mechanisms of action to emulate endogenous stress-coping strategies. Copyright © 2011 IBRO. Published by Elsevier Ltd. All rights reserved.

Peeling off the genetics of atopic dermatitis-like congenital disorders.

PubMed

Samuelov, Liat; Sprecher, Eli

2014-10-01

The epidermis forms during the course of a complex differentiation process known as cornification, which culminates with the formation of the epidermal barrier. The epidermal barrier serves as a vital line of defense against the environment and mainly consists of 3 elements: intracellular keratin filaments, intercellular lipids, and the cornified cell envelope. Adequate epidermal barrier function is also critically dependent on normal shedding of terminally differentiated keratinocytes, a process termed desquamation, which requires the dissolution of cell-cell junctions in the upper granular layers. Although much has been learned about epidermal differentiation through the deciphering of the molecular basis of various cornification disorders, less is currently known about the mechanisms regulating epidermal desquamation and disorders resulting from disruption of this process. Netherton syndrome, peeling skin syndrome type B, and skin dermatitis--multiple severe allergies--metabolic wasting syndrome are 3 autosomal recessive conditions resulting from aberrant regulation of epidermal desquamation. The deciphering of their pathogenesis has not only broadened our understanding of this process but has also shed new light on clinical and mechanistic links between allergic reactions and abnormal desquamation, substantiating the notion that allergic manifestations might, under some circumstances, be the sole consequence of a primary epidermal defect. Copyright © 2014 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

Particle Clogging in Filter Media of Embankment Dams: A Numerical and Experimental Study

NASA Astrophysics Data System (ADS)

Antoun, T.; Kanarska, Y.; Ezzedine, S. M.; Lomov, I.; Glascoe, L. G.; Smith, J.; Hall, R. L.; Woodson, S. C.

2013-12-01

The safety of dam structures requires the characterization of the granular filter ability to capture fine-soil particles and prevent erosion failure in the event of an interfacial dislocation. Granular filters are one of the most important protective design elements of large embankment dams. In case of cracking and erosion, if the filter is capable of retaining the eroded fine particles, then the crack will seal and the dam safety will be ensured. Here we develop and apply a numerical tool to thoroughly investigate the migration of fines in granular filters at the grain scale. The numerical code solves the incompressible Navier-Stokes equations and uses a Lagrange multiplier technique which enforces the correct in-domain computational boundary conditions inside and on the boundary of the particles. The numerical code is validated to experiments conducted at the US Army Corps of Engineering and Research Development Center (ERDC). These laboratory experiments on soil transport and trapping in granular media are performed in constant-head flow chamber filled with the filter media. Numerical solutions are compared to experimentally measured flow rates, pressure changes and base particle distributions in the filter layer and show good qualitative and quantitative agreement. To further the understanding of the soil transport in granular filters, we investigated the sensitivity of the particle clogging mechanism to various parameters such as particle size ratio, the magnitude of hydraulic gradient, particle concentration, and grain-to-grain contact properties. We found that for intermediate particle size ratios, the high flow rates and low friction lead to deeper intrusion (or erosion) depths. We also found that the damage tends to be shallower and less severe with decreasing flow rate, increasing friction and concentration of suspended particles. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344 and was sponsored by the Department of Homeland Security (DHS), Science and Technology Directorate, Homeland Security Advanced Research Projects Agency (HSARPA).

Effect of RuO2 growth temperature on ferroelectric properties of RuO2/Pb(Zr, Ti)O3/RuO2/Pt capacitors

NASA Astrophysics Data System (ADS)

Norga, G. J.; Fè, Laura; Wouters, D. J.; Maes, H. E.

2000-03-01

We present a promising method for obtaining Pb(Zr, Ti)O3(PZT) layers with excellent endurance and pulse-switching properties on RuO2 electrodes using the sol-gel method. As the substrate temperature during reactive sputtering of the RuO2 bottom electrode layer is reduced, the (111) PZT texture component becomes more pronounced, an effect attributed to the change from columnar to granular RuO2 film morphology. Reducing the residual PZT (100) and (101) texture components was found to be a necessary condition for obtaining optimal pulse switching and endurance properties of the layers. Highly (111)-oriented PZT layers, obtained on RuO2 grown at 150 °C exhibit a net switched charge of >60 μC/cm2 during pulse measurement and <10% degradation after 1011 fatigue cycles.

Modeling of the processes of natural and waste water purification in the reactor-clarifier

NASA Astrophysics Data System (ADS)

Primak, O. D.; Skolubovich, Yu. L.; Fedorova, N. N.; Voitov, E. L.

2018-03-01

The results of the filtration process simulation in a reactor-clarifier installation using a suspended loading layer are presented. Calculations were carried out in ANSYS Fluent on the basis of the Navier-Stokes equations supplemented by the equations of the Eulerian model of multiphase taking into account granularity of the particle phase. The unsteady picture of the formation of a fluidized («boiling») layer of particles is obtained. The results of parametric calculations allowing to estimate the effect of the flow velocity, the loading layer thickness, the thickness of sand and other parameters on the fluidized bed structure are presented. The liquid flow rate at which the loading grains are not washed out is determined. The diameter of particles and the height of the loading layer, at which the filter material is suspended and thus normal operation of the plant is ensured, are defined.

Size invariance of the granular Rayleigh-Taylor instability.

PubMed

Vinningland, Jan Ludvig; Johnsen, Øistein; Flekkøy, Eirik G; Toussaint, Renaud; Måløy, Knut Jørgen

2010-04-01

The size scaling behavior of the granular Rayleigh-Taylor instability [J. L. Vinningland, Phys. Rev. Lett. 99, 048001 (2007)] is investigated experimentally, numerically, and theoretically. An upper layer of grains displaces a lower gap of air by organizing into dense fingers of falling grains separated by rising bubbles of air. The dependence of these structures on the system and grain sizes is investigated. A spatial measurement of the finger structures is obtained by the Fourier power spectrum of the wave number k. As the size of the grains increases the wave number decreases accordingly which leaves the dimensionless product of wave number and grain diameter, dk, invariant. A theoretical interpretation of the invariance, based on the scaling properties of the model equations, suggests a gradual breakdown of the invariance for grains smaller than approximately 70 microm or greater than approximately 570 microm in diameter.

On the micromechanics of slip events in sheared, fluid-saturated fault gouge

NASA Astrophysics Data System (ADS)

Dorostkar, Omid; Guyer, Robert A.; Johnson, Paul A.; Marone, Chris; Carmeliet, Jan

2017-06-01

We used a three-dimensional discrete element method coupled with computational fluid dynamics to study the poromechanical properties of dry and fluid-saturated granular fault gouge. The granular layer was sheared under dry conditions to establish a steady state condition of stick-slip dynamic failure, and then fluid was introduced to study its effect on subsequent failure events. The fluid-saturated case showed increased stick-slip recurrence time and larger slip events compared to the dry case. Particle motion induces fluid flow with local pressure variation, which in turn leads to high particle kinetic energy during slip due to increased drag forces from fluid on particles. The presence of fluid during the stick phase of loading promotes a more stable configuration evidenced by higher particle coordination number. Our coupled fluid-particle simulations provide grain-scale information that improves understanding of slip instabilities and illuminates details of phenomenological, macroscale observations.

Synthesis of ultra-nano-carbon composite materials with extremely high conductivity by plasma post-treatment process of ultrananocrystalline diamond films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yeh, Chien-Jui; Leou, Keh-Chyang; Manoharan, Divinah

2015-08-24

Needle-like diamond grains encased in nano-graphitic layers are an ideal granular structure of diamond films to achieve high conductivity and superior electron field emission (EFE) properties. This paper describes the plasma post-treatment (ppt) of ultrananocrystalline diamond (UNCD) films at low substrate temperature to achieve such a unique granular structure. The CH{sub 4}/N{sub 2} plasma ppt-processed films exhibit high conductivity of σ = 1099 S/cm as well as excellent EFE properties with turn-on field of E{sub 0} = 2.48 V/μm (J{sub e} = 1.0 mA/cm{sup 2} at 6.5 V/μm). The ppt of UNCD film is simple and robust process that is especially useful for device applications.

Fracture surfaces of granular pastes.

PubMed

Mohamed Abdelhaye, Y O; Chaouche, M; Van Damme, H

2013-11-01

Granular pastes are dense dispersions of non-colloidal grains in a simple or a complex fluid. Typical examples are the coating, gluing or sealing mortars used in building applications. We study the cohesive rupture of thick mortar layers in a simple pulling test where the paste is initially confined between two flat surfaces. After hardening, the morphology of the fracture surfaces was investigated, using either the box counting method to analyze fracture profiles perpendicular to the mean fracture plane, or the slit-island method to analyze the islands obtained by cutting the fracture surfaces at different heights, parallel to the mean fracture plane. The fracture surfaces were shown to exhibit scaling properties over several decades. However, contrary to what has been observed in the brittle or ductile fracture of solid materials, the islands were shown to be mass fractals. This was related to the extensive plastic flow involved in the fracture process.

Construction demolition wastes, Waelz slag and MSWI bottom ash: a comparative technical analysis as material for road construction.

PubMed

Vegas, I; Ibañez, J A; San José, J T; Urzelai, A

2008-01-01

The objective of the study is to analyze the technical suitability of using secondary materials from three waste flows (construction and demolition waste (CDW), Waelz slag and municipal solid waste incineration (MSWI) bottom ash), under the regulations and standards governing the use of materials for road construction. A detailed technical characterization of the materials was carried out according to Spanish General Technical Specifications for Road Construction (PG3). The results show that Waelz slag can be adequate for using in granular structural layers, while CDW fits better as granular material in roadbeds. Likewise, fresh MSWI bottom ash can be used as roadbed material as long as it does not contain a high concentration of soluble salts. This paper also discusses the adequacy of using certain traditional test methods for natural soils when characterizing secondary materials for use as aggregates in road construction.

An erythrodermic variant of pemphigus foliaceus with puzzling histologic and immunopathologic features.

PubMed

Peterson, Jennifer D; Worobec, Sophie M; Chan, Lawrence S

2007-01-01

Pemphigus foliaceus is an autoimmune blistering disorder that affects the skin owing to autoantibodies against desmoglein 1. We employed clinical, histologic, immunopathologic, and serum laboratory studies to investigate a case of an erythrodermic variant of pemphigus foliaceus in an elderly man following treatment with bisoprolol-hydrochlorothiazide. Early histopathology revealed psoriasiform dermatitis, but later biopsies showed subcorneal and granular layer separation with neutrophilic infiltrate. Direct immunofluorescence showed intercellular deposits of immunoglobulin G throughout the epidermis, granular staining of C3 along the basement membrane zone, and fibrin and C3 deposition around the blood vessels. Indirect immunofluorescence on monkey esophagus showed a titer of greater than 1:1,280. Indirect immunofluorescence on rat bladder, antinuclear antibody, lupus panel, and kidney function panel were all negative. There are no reports in the literature of pemphigus foliaceus being induced by bisoprolol, but reports exist of propanolol resulting in drug-induced pemphigus foliaceus.