455 research outputs found
Microvascular Architecture of the Filiform Papillae in Primates and Insectivores
The microvascular architecture of filiform papillae was investigated under a scanning electron microscope in man, Japanese monkeys, common squirrel monkeys, common marmosets, common tree shrews, large Japanese moles and dwarf shrews utilizing microvascular corrosion casts. Filiform papillae were circularly arranged in primates, and each of them was supplied by a hairpin capillary loop. These papillae sometimes were aggregated. The filiform papillae of Japanese monkeys exhibited markedly locational differences on the lingual dorsum and were supplied by circularly arranged capillary loops or by an intrapapillary capillary network. Small filiform papillae were located on an epithelial eminence in the lingual radix, each of them supplied by a low and simple hairpin capillary loop. The aggregated filiform papillae of common squirrel monkeys were less frequent without any locational differences. Low filiform papillae of common marmosets and tree shrews were simpler in form, being arranged in a circle and supplied by a simple hairpin capillary loop. The filiform papillae of insectivores were not arranged in a circle. The filiform papillae of dwarf shrews were supplied by an incomplete capillary ring without a loop. With respect to species differences, the circularly arranged capillary loops in man were most complicated and highly developed. Microvascular architecture of the filiform papillae of insectivores was much simpler, different from those observed in primates
Construction of microfluidic biochips with enhanced functionalities using 3D femtosecond laser direct writing
The extreme nonlinear interaction betweenfemtosecond laser pulses and large-band-gapmaterials has enabled three-dimensional (3D)microfabrication inside transparent materials. In thepast decade, this technique has been used forcreating a variety of functional components in glassmaterials, including microoptics, microfluidics,microelectronics, micromechanics, etc. Using thesebuilding blocks, femtosecond laser microfabricationalso allows for construction of highly integratedmicrodevices. Here, we provide an overview of ourlatest progress made along this direction, includingfocal spot engineering and nanofluidic fabrication.In particular, we show that 3D micro-/nano-fluidiccomponents with arbitrary geometries can bedirectly formed inside glass. This opens uppromising prospects for a broad spectrum ofapplications based on compact and complex 3Dmicrofluidic networks. Our work shows that thistechnique holds promise for fabricating 3D hybridmicro-systems, such as Lab-on-a-chip devices andMicro Total Analysis Systems in the future
A Novel Role of the NRF2 Transcription Factor in the Regulation of Arsenite-Mediated Keratin 16 Gene Expression in Human Keratinocytes
Reproduced with permission from Environmental Health Perspectives
publisherBACKGROUND: Inorganic sodium arsenite (iAs) is a ubiquitous environmental contaminant and is associated with an increased risk of skin hyperkeratosis and cancer. OBJECTIVES: We investigated the molecular mechanisms underlying the regulation of the keratin 16 (K16) gene by iAs in the human keratinocyte cell line HaCaT. METHODS: We performed reverse transcriptase polymerase chain reaction, luciferase assays, Western blots, and electrophoretic mobility shift assays to determine the transcriptional regulation of the K16 gene by iAs. We used gene overexpression approaches to elucidate the nuclear factor erythroidderived2 related factor 2 (NRF2) involved in the K16 induction. RESULTS: iAs induced the mRNA and protein expression of K16. We also found that the expression of K16 was transcriptionally induced by iAs through activator protein-1âlike sites and an antioxidant response element (ARE) in its gene promoter region. Treatment with iAs also enhanced the production and translocation of the NRF2 transcription factor, an ARE-binding protein, into the nucleus without modification of its mRNA expression. In addition, iAs elongated the half-life of the NRF2 protein. When overexpressed in HaCaT cells, NRF2 was also directly involved in not only the up-regulation of the detoxification gene thioredoxin but also K16 gene expression.CONCLUSIONS: Our data clearly indicate that the K16 gene is a novel target of NRF2. Furthermore, our findings also suggest that NRF2 has opposing roles in the cellâin the activation of detoxification pathways and in promoting the development of skin disorders
On the vertical extent of the large low shear velocity province beneath the South Pacific Superswell
International audienceThe three-dimensional S-wave velocity structure beneath the South Pacific Superswell is obtained from joint broadband seismic experiments on the ocean floor and islands. We collected only approximately 800 relative times of long-period teleseismic SH-waves by using a waveform cross-correlation from 76 events occurring from January 2003 to May 2005. We conducted relative time tomography to obtain a 3D structure to depths of 1600 km. In the resultant image, we find a characteristic distribution of low- velocity regions. The most prominent features are a large doughnut-shaped low-velocity region at 800 km depth, and an elongated large low-velocity region beneath the Society to Pitcairn hotspots at 1200 km depth. Our model suggests that a large low shear velocity province rooted in the D00 extends upwards and culminates near the top of the lower mantle beneath the central part of the South Pacific Superswell although its perfect continuity is not still confirmed
P-wave tomography of the mantle beneath the South Pacific Superswell revealed by joint ocean floor and islands broadband seismic experiments
International audienceThree-dimensional P-wave velocity structure of the mantle beneath the South Pacific Superswell is determined through passive broadband seismic experiments on the ocean floor and islands between 2003 and 2005. We collected approximately 1500 relative times of long-period teleseismic P-waves by using a waveform cross-correlation. We analyzed this data set with relative time tomography to depths of 2000 km. The resultant structure shows lateral heterogeneity of approximately +/- 2%, in which a distinct low velocity region is found beneath the center of the Superswell at a depth of 1600 km. At 1200km depth, an elongated low velocity region is found beneath the Society to Pitcairn hotspots. At 800 km depth, two linear low velocity regions are located beneath Tuamotu and Austral islands. Isolated low velocity regions are identified beneath the Society, Marquesas, and Macdonald hotspots at 400 km depth. Our new tomographic images reveal that the large low velocity region rooted in the deep lower mantle is split into two sheets at 1200 km depth and these terminate at approximately 800 km depth. This feature appears to be consistent with the characteristics of a thermo-chemical pile or dome
Laser-chemical vapor deposition of W Schottky contacts on GaAs\ud using WF6 and SiH4
Reports on the deposition of tungsten on gallium arsenide (GaAs) using a low-temperature laser-chemical vapor deposition process. Induction of metallic W formation from a gas mixture; Columnar structure shown by scanning electron microscopy of the W films; Schottky diodes obtained during a laser based resistless projection patterning process on GaAs
Flow Measurements via Two-particle Azimuthal Correlations in Au + Au Collisions at sqrt(s_NN) = 130 GeV
Two particle azimuthal correlation functions are presented for charged
hadrons produced in Au + Au collisions at RHIC sqrt(s_NN) = 130 GeV. The
measurements permit determination of elliptic flow without event-by-event
estimation of the reaction plane. The extracted elliptic flow values v_2 show
significant sensitivity to both the collision centrality and the transverse
momenta of emitted hadrons, suggesting rapid thermalization and relatively
strong velocity fields. When scaled by the eccentricity of the collision zone,
epsilon, the scaled elliptic flow shows little or no dependence on centrality
for charged hadrons with relatively low p_T. A breakdown of this epsilon
scaling is observed for charged hadrons with p_T > 1.0 GeV/c for the most
central collisions.Comment: 6 pages, RevTeX 3, 4 figures, 307 authors, submitted to Phys. Rev.
Lett. on 11 April 2002. Plain text data tables for the points plotted in
figures for this and previous PHENIX publications are (will be made) publicly
available at http://www.phenix.bnl.gov/phenix/WWW/run/phenix/papers.htm
Net Charge Fluctuations in Au + Au Interactions at sqrt(s_NN) = 130 GeV
Data from Au + Au interactions at sqrt(s_NN) = 130 GeV, obtained with the
PHENIX detector at RHIC, are used to investigate local net charge fluctuations
among particles produced near mid-rapidity. According to recent suggestions,
such fluctuations may carry information from the Quark Gluon Plasma. This
analysis shows that the fluctuations are dominated by a stochastic distribution
of particles, but are also sensitive to other effects, like global charge
conservation and resonance decays.Comment: 6 pages, RevTeX 3, 3 figures, 307 authors, submitted to Phys. Rev.
Lett. on 21 March, 2002. Plain text data tables for the points plotted in
figures for this and previous PHENIX publications are (will be made) publicly
available at http://www.phenix.bnl.gov/phenix/WWW/run/phenix/papers.htm
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