Mucosal colonization by metastatic carcinoma in the gastrointestinal tract: a potential mimic of primary neoplasia.

PubMed

Estrella, Jeannelyn S; Wu, Tsung-Teh; Rashid, Asif; Abraham, Susan C

2011-04-01

The gastrointestinal (GI) tract is a common site for both primary and metastatic carcinomas. Distinguishing the two can occasionally be difficult, particularly when metastatic tumor reaches the mucosal surface. Features that are typically used to make this distinction include the presence of an adenomatous precursor lesion, regional lymph node involvement, and gross configuration of the tumor. However, we recently encountered 2 index cases of metastatic carcinoma in the small intestine (1 from the colorectum and 1 of endocervical origin) that were initially misinterpreted as primary small bowel carcinomas because of apparent in situ growth in the mucosal surface resembling polypoid, adenomatous precursor lesions. We, therefore, studied 100 GI resections from 1987 to 2009 that were reported to show mucosal involvement by metastatic carcinoma, and compared the histologic features with a control group of 29 primary small bowel adenocarcinomas. Gross descriptions and histologic sections were evaluated for the following: (1) tumor spread along an intact basement membrane of villi/crypts (mucosal colonization), (2) resemblance to an adenoma/precursor lesion, (3) gross configuration of the tumor, (4) lymphovascular invasion, and (5) regional lymph node involvement in the metastatic site. Metastatic sites included the small intestine (n=74), colorectum (n=16), or both (n=10). Primary tumors were GI (n=55, with 47 from colorectum), gynecologic (n=28), pulmonary (n=8), genitourinary (n=6), head and neck (n=2), and breast (n=1). Overall, 42 (42%) of the metastases that reached the mucosal surface of the bowel showed at least focal mucosal colonization, 26% resembled a precursor adenoma, 62% had regional lymph node positivity, and only 24% cases showed a classic serosal-based configuration. In 4 cases (2 of GI origin and 2 of gynecologic origin), metastatic tumors were initially interpreted as new primaries by the pathologist (n=2) or clinicians (n=2). Metastatic carcinomas originating from the GI tract were significantly more likely to show mucosal colonization (60% vs. 20%, P<0.0001) and resemblance to a precursor lesion (45% vs. 2%, P<0.0001) than other primary tumors. In a comparison between 29 primary small bowel carcinomas and 41 metastatic colorectal carcinomas in the small bowel, metastatic tumors were distinguished by a higher prevalence of multiple lesions (0% vs. 39%, P<0.0001), whereas small bowel primaries were more likely to show high tumor grade (41% vs. 17%, P=0.03). There were no significant differences in the mean age (61.4 y vs. 60.9 y), number of male participants (69% vs. 56%), growth along basement membranes (62% vs. 63%), apparent precursor lesion (55% vs. 46%), lymphovascular invasion (69% vs. 73%), or lymph node positivity (68% vs. 37.5%, P=0.065). These results confirm that metastatic carcinomas involving the mucosal surface of the intestines frequently exhibit gross and histologic features, which mimic second primaries, especially when they originate from the GI tract. In situ growth and presence of an apparent adenoma cannot be taken as prima facie evidence of a primary neoplasm.

Discrimination of artificial categories structured by family resemblances: a comparative study in people (Homo sapiens) and pigeons (Columba livia).

PubMed

Makino, Hiroshi; Jitsumori, Masako

2007-02-01

Adult humans (Homo sapiens) and pigeons (Columba livia) were trained to discriminate artificial categories that the authors created by mimicking 2 properties of natural categories. One was a family resemblance relationship: The highly variable exemplars, including those that did not have features in common, were structured by a similarity network with the features correlating to one another in each category. The other was a polymorphous rule: No single feature was essential for distinguishing the categories, and all the features overlapped between the categories. Pigeons learned the categories with ease and then showed a prototype effect in accord with the degrees of family resemblance for novel stimuli. Some evidence was also observed for interactive effects of learning of individual exemplars and feature frequencies. Humans had difficulty in learning the categories. The participants who learned the categories generally responded to novel stimuli in an all-or-none fashion on the basis of their acquired classification decision rules. The processes that underlie the classification performances of the 2 species are discussed.

Biological adaptations for functional features of language in the face of cultural evolution.

PubMed

Christiansen, Morten H; Reali, Florencia; Chater, Nick

2011-04-01

Although there may be no true language universals, it is nonetheless possible to discern several family resemblance patterns across the languages of the world. Recent work on the cultural evolution of language indicates the source of these patterns is unlikely to be an innate universal grammar evolved through biological adaptations for arbitrary linguistic features. Instead, it has been suggested that the patterns of resemblance emerge because language has been shaped by the brain, with individual languages representing different but partially overlapping solutions to the same set of nonlinguistic constraints. Here, we use computational simulations to investigate whether biological adaptation for functional features of language, deriving from cognitive and communicative constraints, may nonetheless be possible alongside rapid cultural evolution. Specifically, we focus on the Baldwin effect as an evolutionary mechanism by which previously learned linguistic features might become innate through natural selection across many generations of language users. The results indicate that cultural evolution of language does not necessarily prevent functional features of language from becoming genetically fixed, thus potentially providing a particularly informative source of constraints on cross-linguistic resemblance patterns.

Glycosylation and immunocytochemistry of binucleate cells in pronghorn (Antilocapra americana, Antilocapridae) show features of both Giraffidae and Bovidae.

PubMed

Jones, Carolyn J P; Silvia, W J; Hamilton, C H; Geary, T W; Zezeski, A L; Wooding, F B P

2017-09-01

Although the pronghorn (Antilocapra americana) resembles an antelope, its nearest relatives are the giraffe and okapi. In this study we have examined the placentae of 6 pronghorns using lectin- and immunocytochemistry to identify giraffid and bovid features. Binucleate cells (BNC) of the placenta exhibited features intermediate between those of the giraffe and bovine; Dolichos biflorus agglutinin binding - strong in the bovine BNC and absent in the giraffe - was evident in only a subpopulation of BNC while binding to blood vessels, as in the giraffe. Binding of Phytolacca americana agglutinin resembled that of the giraffe and okapi whereas many other glycans were found in all four clades. PAG antigens were similar to bovine and okapi but not giraffe. In summary, although the pronghorn outwardly resembles an antelope, placental BNC show giraffid features. Although each clade has its own individual characteristics, there are far more similarities than differences between them, emphasizing the common ancestry of all four clades. Copyright © 2017 Elsevier Ltd. All rights reserved.

Analyzing surface features on icy satellites using a new two-layer analogue model

NASA Astrophysics Data System (ADS)

Morales, K. M.; Leonard, E. J.; Pappalardo, R. T.; Yin, A.

2017-12-01

The appearance of similar surface morphologies across many icy satellites suggests potentially unified formation mechanisms. Constraining the processes that shape the surfaces of these icy worlds is fundamental to understanding their rheology and thermal evolution—factors that have implications for potential habitability. Analogue models have proven useful for investigating and quantifying surface structure formation on Earth, but have only been sparsely applied to icy bodies. In this study, we employ an innovative two-layer analogue model that simulates a warm, ductile ice layer overlain by brittle surface ice on satellites such as Europa and Enceladus. The top, brittle layer is composed of fine-grained sand while the ductile, lower viscosity layer is made of putty. These materials were chosen because they scale up reasonably to the conditions on Europa and Enceladus. Using this analogue model, we investigate the role of the ductile layer in forming contractional structures (e.g. folds) that would compensate for the over-abundance of extensional features observed on icy satellites. We do this by simulating different compressional scenarios in the analogue model and analyzing whether the resulting features resemble those on icy bodies. If the resulting structures are similar, then the model can be used to quantify the deformation by calculating strain. These values can then be scaled up to Europa or Enceladus and used to quantity the observed surface morphologies and the amount of extensional strain accommodated by certain features. This presentation will focus on the resulting surface morphologies and the calculated strain values from several analogue experiments. The methods and findings from this work can then be expanded and used to study other icy bodies, such as Triton, Miranda, Ariel, and Pluto.

A scanning electron microscopic study of 34 cases of acute granulocytic, myelomonocytic, monoblastic and histiocytic leukemia.

PubMed

Polliack, A; McKenzie, S; Gee, T; Lampen, N; de Harven, E; Clarkson, B D

1975-09-01

This report describes the surface architecture of leukemic cells, as seen by scanning electron microscopy in 34 patients with acute nonlymphoblastic leukemia. Six patients with myeloblastic, 4 with promyelocytic, 10 with myelomonocytic, 8 with monocytic, 4 with histiocytic and 2 with undifferentiated leukemia were studied. Under the scanning electron microscope most leukemia histiocytes and monocytes appeared similar and were characterized by the presence of large, well developed broad-based ruffled membranes or prominent raised ridge-like profiles, resembling ithis respect normal monocytes. Most cells from patients with acute promyelocytic or myeloblastic leukemia exhibited narrower ridge-like profiles whereas some showed ruffles or microvilli. Patients with myelomonocytic leukemia showed mixed populations of cells with ridge-like profiles and ruffled membranes whereas cells from two patients with undifferentiated leukemia had smooth surfaces, similar to those encountered in cells from patients with acute lymphoblastic leukemia. It appears that nonlymphoblastic and lymphoblastic leukemia cells (particularly histiocytes and monocytes) can frequently be distinquished on the basis of their surface architecture. The surface features of leukemic histiocytes and monocytes are similar, suggesting that they may belong to the same cell series. The monocytes seem to have characteristic surface features recognizable with the scanning electron microscope and differ from most cells from patients with acute granulocytic leukemia. Although overlap of surface features and misidentification can occur, scanning electron microscopy is a useful adjunct to other modes of microscopy in the study and diagnosis of acute leukemia.

Crystal structure of casein kinase-1, a phosphate-directed protein kinase.

PubMed Central

Xu, R M; Carmel, G; Sweet, R M; Kuret, J; Cheng, X

1995-01-01

The structure of a truncated variant of casein kinase-1 from Schizosaccharomyces pombe, has been determined in complex with MgATP at 2.0 A resolution. The model resembles the 'closed', ATP-bound conformations of the cyclin-dependent kinase 2 and the cAMP-dependent protein kinase, with clear differences in the structure of surface loops that impart unique features to casein kinase-1. The structure is of unphosphorylated, active conformation of casein kinase-1 and the peptide-binding site is fully accessible to substrate. Images PMID:7889932

Television observations of Mercury by Mariner 10

NASA Technical Reports Server (NTRS)

Murray, B. C.; Belton, M. J. S.; Danielson, E. G.; Davies, M. E.; Gault, D. E.; Hapke, B.; Oleary, B.; Strom, R. G.; Suomi, V.; Trask, N.

1977-01-01

The morphology and optical properties of the surface of Mercury resemble those of the Moon in remarkable detail, recording a very similar sequence of events; chemical and mineralogical similarity of the outer layers is implied. Mercury is probably a differentiated planet with an iron-rich core. Differentiation is inferred to have occurred very early. No evidence of atmospheric modification of any landform is found. Large-scale scarps and ridges unlike lunar or Martian features may reflect a unique period of planetary compression near the end of heavy bombardment, perhaps related to contraction of the core.

Television observations of Mercury by Mariner 10

NASA Technical Reports Server (NTRS)

Murray, B. C.; Belton, M. J. S.; Danielson, G. E.; Davies, M. E.; Gault, D. E.; Hapke, B.; Oleary, B.; Strom, R. G.; Suomi, V.; Trask, N.

1974-01-01

The morphology and optical properties of the surface of Mercury resemble that of the moon in remarkable detail, recording a very similar sequence of events; chemical and mineralogical similarity of the outer layers is implied. Mercury is probably a differentiated planet with an iron-rich core. Differentiation is inferred to have occurred very early. No evidence of atmospheric modification of any landform is found. Large-scale scarps and ridges unlike lunar or Martian features may reflect a unique period of planetary compression near the end of heavy bombardment, perhaps related to contraction of the core.

Microbiota fingerprints lose individually identifying features over time.

PubMed

Wilkins, David; Leung, Marcus H Y; Lee, Patrick K H

2017-01-09

Humans host individually unique skin microbiota, suggesting that microbiota traces transferred from skin to surfaces could serve as forensic markers analogous to fingerprints. While it is known that individuals leave identifiable microbiota traces on surfaces, it is not clear for how long these traces persist. Moreover, as skin and surface microbiota change with time, even persistent traces may lose their forensic potential as they would cease to resemble the microbiota of the person who left them. We followed skin and surface microbiota within households for four seasons to determine whether accurate microbiota-based matching of individuals to their households could be achieved across long time delays. While household surface microbiota traces could be matched to the correct occupant or occupants with 67% accuracy, accuracy decreased substantially when skin and surface samples were collected in different seasons, and particularly when surface samples were collected long after skin samples. Most OTUs persisted on skin or surfaces for less than one season, indicating that OTU loss was the major cause of decreased matching accuracy. OTUs that were more useful for individual identification persisted for less time and were less likely to be deposited from skin to surface, suggesting a trade-off between the longevity and identifying value of microbiota traces. While microbiota traces have potential forensic value, unlike fingerprints they are not static and may degrade in a way that preferentially erases features useful in identifying individuals.

A spreading drop model for plumes on Venus

NASA Astrophysics Data System (ADS)

Koch, D. M.

1994-01-01

Many of the large-scale, plume-related features on Venus can be modeled by a buoyant viscous drop, or plume head, as it rises and spreads laterally below a free fluid surface. The drop has arbitrary density and viscosity contrast and begins as a sphere below the surface of a fluid half space. The boundary integral method is used to solve for the motion of the plume head and for the topography, geoid, and stress at the fluid surface. As the plume approaches the surface, stresses in the fluid above it cause it to spread and become thin below the surface. During the spreading, the surface swell above evolves through various stages whose morphologies resemble several different plume-related features observed on Venus. When the plume head first approaches the surface, a high broad topographic dome develops, with a large geoid, and radial extensional deformation patterns. At later stages, the topography subsides and becomes plateau-like, the geoid to topography ratio (GTR) decreases, and the dominant stress pattern consists of a band of concentric extension surrounded by a band of concentric compression. We find that a low-viscosity model plume head (viscosity that is 0.1 times the mantle viscosity) produces maximum topography that is 20% lower, and swell features which evolve faster, than for an isoviscous plume. We compare model results with both the large-scale highland swells, and smaller-scale features such as coronae and novae. The dome-shaped highlands with large GTRs such as Beta, Atla, and Western Eistla Regiones may be the result of early stage plume motion, while the flatter highlands such as Ovda and Thetis Regiones which have lower GTRs may be later stage features. Comparison of model results with GTR data indicates that the highlands result from plume heads with initial diameters of about 1000 km. On a smaller scale, an evolutionary sequence may begin with novae (domes having radial extensional deformation), followed by features with radial and concentric deformation (such as arachnoids), and end with coronae (with mostly concentric deformation). The model predicts that the highlands evolve on a timescale of order 10 Ma, and the smaller-scale features evolve in a 100 Ma timescale.

Evidence for subduction in the ice shell of Europa

NASA Astrophysics Data System (ADS)

Kattenhorn, Simon A.; Prockter, Louise M.

2014-10-01

Jupiter’s icy moon Europa has one of the youngest planetary surfaces in the Solar System, implying rapid recycling by some mechanism. Despite ubiquitous extension and creation of new surface area at dilational bands that resemble terrestrial mid-ocean spreading zones, there is little evidence of large-scale contraction to balance the observed extension or to recycle ageing terrains. We address this enigma by presenting several lines of evidence that subduction may be recycling surface material into the interior of Europa’s ice shell. Using Galileo spacecraft images, we produce a tectonic reconstruction of geologic features across a 134,000 km2 region of Europa and find, in addition to dilational band spreading, evidence for transform motions along prominent strike-slip faults, as well as the removal of approximately 20,000 km2 of the surface along a discrete tabular zone. We interpret this zone as a subduction-like convergent boundary that abruptly truncates older geological features and is flanked by potential cryolavas on the overriding ice. We propose that Europa’s ice shell has a brittle, mobile, plate-like system above convecting warmer ice. Hence, Europa may be the only Solar System body other than Earth to exhibit a system of plate tectonics.

Formation of Martian Gullies by the Action of Liquid Water Flowing Under Current Martian Environmental Conditions

NASA Technical Reports Server (NTRS)

Heldmann, J. L.; Toon, O. B.; Pollard, W. H.; Mellon, M. T.; Pitlick, J.; McKay, C. P.; Andersen, D. T.

2005-01-01

Images from the Mars Orbiter Camera (MOC) on the Mars Global Surveyor (MGS) spacecraft show geologically young small-scale features resembling terrestrial water-carved gullies. An improved understanding of these features has the potential to reveal important information about the hydrological system on Mars, which is of general interest to the planetary science community as well as the field of astrobiology and the search for life on Mars. The young geologic age of these gullies is often thought to be a paradox because liquid water is unstable at the Martian surface. Current temperatures and pressures are generally below the triple point of water (273 K, 6.1 mbar) so that liquid water will spontaneously boil and/or freeze. We therefore examine the flow of water on Mars to determine what conditions are consistent with the observed features of the gullies.

Everyone Wins: A Mars-Impact Origin for Carbonaceous Phobos and Deimos

NASA Technical Reports Server (NTRS)

Fries, M.; Welzenbach, L.; Steele, A.

2016-01-01

Discussions of Phobos' and Deimos' origin(s) tend to feature an orthogonally opposed pair of observations: dynamical studies which favor coalescence of the moons from an orbital debris ring arising from a large impact on Mars; and reflectance spectroscopy of the moons that indicate a carbonaceous composition that is not consistent with Martian surface materials. One way to reconcile this discrepancy is to consider the option of a Mars-impact origin for Phobos and Deimos, followed by surficial decoration of carbon-rich materials by interplanetary dust particles (IDP). The moons experience a high IDP flux because of their location in Mars' gravity well. Calculations show that accreted carbon is sufficient to produce a surface with reflectance spectra resembling carbonaceous chondrites.

Wave breaking induced surface wakes and jets observed during a bora event

NASA Astrophysics Data System (ADS)

Jiang, Qingfang; Doyle, James D.

2005-09-01

An observational and modeling study of a bora event that occurred during the field phase of the Mesoscale Alpine Programme is presented. Research aircraft in-situ measurements and airborne remote-sensing observations indicate the presence of strong low-level wave breaking and alternating surface wakes and jets along the Croatian coastline over the Adriatic Sea. The observed features are well captured by a high-resolution COAMPS simulation. Analysis of the observations and modeling results indicate that the long-extending wakes above the boundary layer are induced by dissipation associated with the low-level wave breaking, which locally tends to accelerate the boundary layer flow beneath the breaking. Farther downstream of the high peaks, a hydraulic jump occurs in the boundary layer, which creates surface wakes. Downstream of lower-terrain (passes), the boundary layer flow stays strong, resembling supercritical flow.

Investigating Deliquescence of Mars-like Soils from the Atacama Desert and Implications for Liquid Water Near the Martian Surface

NASA Astrophysics Data System (ADS)

Van Alstyne, A. M.; Tolbert, M. A.; Gough, R. V.; Primm, K.

2017-12-01

Recent images obtained from orbiters have shown that the Martian surface is more dynamic than previously thought. These images, showing dark features that resemble flowing water near the surface, have called into question the habitability of the Mars today. Recurring slope lineae (RSL), or the dark features seen in these images, are characterized as narrow, dark streaks that form and grow in the warm season, fade in the cold season, and recur seasonally. It is widely hypothesized that the movement of liquid water near the surface is what causes the appearance of RSL. However, the origin of the water and the potential for water to be stable near the surface is a question of great debate. Here, we investigate the potential for stable or metastable liquid water via deliquescence and efflorescence. The deliquescent properties of salts from the Atacama Desert, a popular terrestrial analog for Martian environments, were investigated using a Raman microscope outfitted with an environmental cell. The salts were put under Mars-relevant conditions and spectra were obtained to determine the presence or absence of liquid phases. The appearance of liquid phases under Mars-relevant conditions would demonstrate that liquid water could be available to cause or play a role in the formations of RSL.

One-pot synthesis of MWW zeolite nanosheets using a rationally designed organic structure-directing agent

DOE PAGES

Luo, Helen Y.; Michaelis, Vladimir K.; Hodges, Sydney; ...

2015-07-22

A new material MIT-1 comprised of delaminated MWW zeolite nanosheets is synthesized in one-pot using a rationally designed organic structure-directing agent (OSDA). The OSDA is comprised of a hydrophilic head segment that resembles the OSDA used to synthesize the zeolite precursor MCM22(P), a hydrophobic tail segment that resembles the swelling agent used to swell MCM22(P), and a di-quaternary ammonium linker that connects both segments. MIT-1 features high crystallinity and surface areas exceeding 500 m 2g -1, and can be synthesized over a wide synthesis window that includes Si/Al ratios ranging from 13 to 67. Characterization data reveal high mesoporosity andmore » acid strength with no detectable amorphous silica phases. In conclusion, compared to MCM-22 and MCM-56, MIT-1 shows a three-fold increase in catalytic activity for the Friedel-Crafts alkylation of benzene with benzyl alcohol.« less

NASA Spacecraft Sees 'Pac-Man' on Saturn Moon

NASA Image and Video Library

2017-12-08

NASA release date March 29, 2010 The highest-resolution-yet temperature map and images of Saturn’s icy moon Mimas obtained by NASA’s Cassini spacecraft reveal surprising patterns on the surface of the small moon, including unexpected hot regions that resemble “Pac-Man” eating a dot, and striking bands of light and dark in crater walls. The left portion of this image shows Mimas in visible light, an image that has drawn comparisons to the "Star Wars" Death Star. The right portion shows the new temperature map, which resembles 1980s video game icon "Pac Man." To learn more about this image go to: www.nasa.gov/centers/goddard/news/features/2010/pac-man-m... Credit: NASA/JPL/Goddard/SWRI/SSI NASA Goddard Space Flight Center is home to the nation's largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.

Search for Feo and Pyroxene on MERCURY?S Surface

NASA Astrophysics Data System (ADS)

Sprague, Ann L.; Emery, Joshua P.

Results from spectral observations of Mercury's surface in the wavelength range 0.8 to 5.5 micrometers will be reported. The data were obtained at the NASA Infrared Telescope Facility on Mauna Kea Hawaii. We used SpeX a long slit imaging system developed at the IRTF for high resolving power spatially resolved spectroscopy throughout the solar system. We aligned the spectral slit with Mercury's geographic longitude and systematically moved it across the Earth-facing disk to obtain multiple disk-resolved spectral images. The entire data set provides spatial coverage of the Earth-facing disk limited only by atmospheric turbulence and the diffraction limit for each wavelength. We used SpeX in two spectral regions in the R 2000 mode. In the first case between 0.8 and 2.5 micrometer to search for the 0.9 to 1.0 micrometer reflectance absorption feature caused by the Fe2+ electronic transfer in FeO. We also measured the 4.5 to 5.5 micrometer flux from Mercury. This is a region of diagnostic features caused by the presence of volume scattering in pyroxene and olivine. These data will be compared to previous observations that showed an anomalous emission feature at 5.5 micrometer and to others that exhibited a feature closely resembling that from pyroxene.

A wolf in sheep's clothing: The description of a fly resembling jumping spider of the genus Scoturius Simon, 1901 (Araneae: Salticidae: Huriini).

PubMed

Perger, Robert; Rubio, Gonzalo D

2018-01-01

Fly resemblance in arthropods is much less common than e.g., resemblance to ants or wasps, and has been mainly observed in beetles. Putative fly mimicry in arachnids has been reported only from the jumping spider genus Saitis. However, recent literature has attributed the fly-resembling characteristics in Saitis to sexual signalling during courtship. The lack of observation of fly mimicry in spiders is not surprising as flies belong to the most important prey item group of spiders. In this study, a new fly-resembling species of the jumping spider tribe Huriini, Scoturius dipterioides sp. nov., from the pre-Andean Chiquitano forest at the Bolivian orocline is described and illustrated. The new species was tentatively placed into Scoturius because the epigynum has a single large elliptical opening. Scoturius dipterioides sp. nov. is distinguished from all other species of this tribe by a combination of following characteristics: epigynum with a large anterior elliptical atrium and initial portion of the copulation ducts dilated as a chamber (shared with Urupuyu); relatively joined copulation openings and short copulation ducts; kidney-shaped spermathecae, advanced at the atrium level. Several somatic features, two of them found exclusively in S. dipterioides sp. nov., increase the resemblance to flies. The Huriini are currently the only spider tribe that is suggested to feature fly mimics.

A wolf in sheep’s clothing: The description of a fly resembling jumping spider of the genus Scoturius Simon, 1901 (Araneae: Salticidae: Huriini)

PubMed Central

Rubio, Gonzalo D.

2018-01-01

Fly resemblance in arthropods is much less common than e.g., resemblance to ants or wasps, and has been mainly observed in beetles. Putative fly mimicry in arachnids has been reported only from the jumping spider genus Saitis. However, recent literature has attributed the fly-resembling characteristics in Saitis to sexual signalling during courtship. The lack of observation of fly mimicry in spiders is not surprising as flies belong to the most important prey item group of spiders. In this study, a new fly-resembling species of the jumping spider tribe Huriini, Scoturius dipterioides sp. nov., from the pre-Andean Chiquitano forest at the Bolivian orocline is described and illustrated. The new species was tentatively placed into Scoturius because the epigynum has a single large elliptical opening. Scoturius dipterioides sp. nov. is distinguished from all other species of this tribe by a combination of following characteristics: epigynum with a large anterior elliptical atrium and initial portion of the copulation ducts dilated as a chamber (shared with Urupuyu); relatively joined copulation openings and short copulation ducts; kidney-shaped spermathecae, advanced at the atrium level. Several somatic features, two of them found exclusively in S. dipterioides sp. nov., increase the resemblance to flies. The Huriini are currently the only spider tribe that is suggested to feature fly mimics. PMID:29364905

The Importance of Chaos and Lenticulae on Europa for the JIMO Mission

NASA Technical Reports Server (NTRS)

Spaun, Nicole A.

2003-01-01

The Galileo Solid State Imaging (SSI) experiment provided high-resolution images of Europa's surface allowing identification of surface features barely distinguishable at Voyager's resolution. SSI revealed the visible pitting on Europa's surface to be due to large disrupted features, chaos, and smaller sub-circular patches, lenticulae. Chaos features contain a hummocky matrix material and commonly contain dislocated blocks of ridged plains. Lenticulae are morphologically interrelated and can be divided into three classes: domes, spots, and micro-chaos. Domes are broad, upwarped features that generally do not disrupt the texture of the ridged plains. Spots are areas of low albedo that are generally smooth in texture compared to other units. Micro-chaos are disrupted features with a hummocky matrix material, resembling that observed within chaos regions. Chaos and lenticulae are ubiquitous in the SSI regional map observations, which average approximately 200 meters per pixel (m/pxl) in resolution, and appear in several of the ultra-high resolution, i.e., better than 50 m/pxl, images of Europa as well. SSI also provided a number of multi-spectral observations of chaos and lenticulae. Using this dataset we have undertaken a thorough study of the morphology, size, spacing, stratigraphy, and color of chaos and lenticulae to determine their properties and evaluate models of their formation. Geological mapping indicates that chaos and micro-chaos have a similar internal morphology of in-situ degradation suggesting that a similar process was operating during their formation. The size distribution denotes a dominant size of 4-8 km in diameter for features containing hummocky material (i.e., chaos and micro-chaos). Results indicate a dominant spacing of 15 - 36 km apart. Chaos and lenticulae are generally among the youngest features stratigraphically observed on the surface, suggesting a recent change in resurfacing style. Also, the reddish non-icy materials on Europa's surface have high concentrations in many chaos and lenticulae features. Nonetheless, a complete global map of the distribution of chaos and lenticulae is not possible with the SSI dataset. Only <20% of the surface has been imaged at 200 m/pxl or better resolution, mostly of the near-equatorial regions. Color and ultra-high-res images have much less surface coverage. Thus we suggest that full global imaging of Europa at 200 m/pxl or better resolution, preferably in multi-spectral wavelengths, should be a high priority for the JIMO mission.

Experiments On Sublimating Carbon Dioxide Ice And Implications For Contemporary Surface Processes On Mars.

PubMed

Mc Keown, L E; Bourke, M C; McElwaine, J N

2017-10-27

Carbon dioxide is Mars' primary atmospheric constituent and is an active driver of Martian surface evolution. CO 2 ice sublimation mechanisms have been proposed for a host of features that form in the contemporary Martian climate. However, there has been very little experimental work or quantitative modelling to test the validity of these hypotheses. Here we present the results of the first laboratory experiments undertaken to investigate if the interaction between sublimating CO 2 ice blocks and a warm, porous, mobile regolith can generate features similar in morphology to those forming on Martian dunes today. We find that CO 2 sublimation can mobilise grains to form (i) pits and (ii) furrows. We have documented new detached pits at the termini of linear gullies on Martian dunes. Based on their geomorphic similarity to the features observed in our laboratory experiments, and on scaling arguments, we propose a new hypothesis that detached pits are formed by the impact of granular jets generated by sublimating CO 2 . We also study the erosion patterns formed underneath a sublimating block of CO 2 ice and demonstrate that these resemble furrow patterns on Mars, suggesting similar formation mechanisms.

Macroparticle generation in DC arc discharge from a WC cathode

NASA Astrophysics Data System (ADS)

Zhirkov, Igor; Polcik, Peter; Kolozsvári, Szilard; Rosen, Johanna

2017-03-01

We have studied macroparticle generation from a tungsten carbide cathode used in a dc vacuum arc discharge. Despite a relatively high decomposition/melting point (˜3100 K), there is an intensive generation of visible particles with sizes in the range 20-35 μm. Visual observations during the discharge and scanning electron microscopy of the cathode surface and of collected macroparticles indicate a new mechanism for particle formation and acceleration. Based on the W-C phase diagram, there is an intensive sublimation of carbon from the melt resulting from the cathode spot. The sublimation supports the formation of a sphere, which is accelerated upon an explosion initiated by Joule heating at the critical contact area between the sphere and the cathode body. The explosive nature of the particle acceleration is confirmed by surface features resembling the remains of a splash on the droplet surface.

Tunable Magnon Weyl Points in Ferromagnetic Pyrochlores.

PubMed

Mook, Alexander; Henk, Jürgen; Mertig, Ingrid

2016-10-07

The dispersion relations of magnons in ferromagnetic pyrochlores with Dzyaloshinskii-Moriya interaction are shown to possess Weyl points, i. e., pairs of topologically nontrivial crossings of two magnon branches with opposite topological charge. As a consequence of their topological nature, their projections onto a surface are connected by magnon arcs, thereby resembling closely Fermi arcs of electronic Weyl semimetals. On top of this, the positions of the Weyl points in reciprocal space can be tuned widely by an external magnetic field: rotated within the surface plane, the Weyl points and magnon arcs are rotated as well; tilting the magnetic field out of plane shifts the Weyl points toward the center Γ[over ¯] of the surface Brillouin zone. The theory is valid for the class of ferromagnetic pyrochlores, i. e., three-dimensional extensions of topological magnon insulators on kagome lattices. In this Letter, we focus on the (111) surface, identify candidates of established ferromagnetic pyrochlores which apply to the considered spin model, and suggest experiments for the detection of the topological features.

Impact of plasma chemistry versus titanium surface topography on osteoblast orientation.

PubMed

Rebl, Henrike; Finke, Birgit; Lange, Regina; Weltmann, Klaus-Dieter; Nebe, J Barbara

2012-10-01

Topographical and chemical modifications of biomaterial surfaces both influence tissue physiology, but unfortunately little knowledge exists as to their combined effect. There are many indications that rough surfaces positively influence osteoblast behavior. Having determined previously that a positively charged, smooth titanium surface boosts osteoblast adhesion, we wanted to investigate the combined effects of topography and chemistry and elucidate which of these properties is dominant. Polished, machined and corundum-blasted titanium of increasing microroughness was additionally coated with plasma-polymerized allylamine (PPAAm). Collagen I was then immobilized using polyethylene glycol diacid and glutar dialdehyde. On all PPAAm-modified surfaces (i) adhesion of human MG-63 osteoblastic cells increased significantly in combination with roughness, (ii) cells resemble the underlying structure and melt with the surface, and (iii) cells overcome the restrictions of a grooved surface and spread out over a large area as indicated by actin staining. Interestingly, the cellular effects of the plasma-chemical surface modification are predominant over surface topography, especially in the initial phase. Collagen I, although it is the gold standard, does not improve surface adhesion features comparably. Copyright © 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Spectrophotometry of peculiar B and A stars. XIV - 56 Arietis, 41 Tauri, 25 Sextantis, HD 170973, HD 205087, and HD 215441

NASA Astrophysics Data System (ADS)

Adelman, S. J.

1983-03-01

Optical region spectrophotometry of six relatively hot Ap stars is presented. Additional scans of 56 Ari extend the results of an earlier paper in this series. The data for 41 Tau, 25 Sex, HD 170973, and HD 215441 are studied as a function of phase. The observations of HD 205087 are inconclusive about its variability although they show spectrophotometrically that it is a definite Ap star. The observations of HD 215441 show a prominent λ5200 broad, continuum feature with an unusual shape. However, when the data are corrected for interstellar reddening, the energy distribution resembles those of other silicon stars. The λ5200 feature is found to be variable in phase with the U-B and B-V colors and with the magnetic field strength. This feature is strongest when the Balmer jump is smallest, the Paschen continuum the bluest according to B-V, and the surface magnetic field strength the largest.

Human Tau Isoforms Assemble into Ribbon-like Fibrils That Display Polymorphic Structure and Stability*

PubMed Central

Wegmann, Susanne; Jung, Yu Jin; Chinnathambi, Subashchandrabose; Mandelkow, Eva-Maria; Mandelkow, Eckhard; Muller, Daniel J.

2010-01-01

Fibrous aggregates of Tau protein are characteristic features of Alzheimer disease. We applied high resolution atomic force and EM microscopy to study fibrils assembled from different human Tau isoforms and domains. All fibrils reveal structural polymorphism; the “thin twisted” and “thin smooth” fibrils resemble flat ribbons (cross-section ∼10 × 15 nm) with diverse twist periodicities. “Thick fibrils” show periodicities of ∼65–70 nm and thicknesses of ∼9–18 nm such as routinely reported for “paired helical filaments” but structurally resemble heavily twisted ribbons. Therefore, thin and thick fibrils assembled from different human Tau isoforms challenge current structural models of paired helical filaments. Furthermore, all Tau fibrils reveal axial subperiodicities of ∼17–19 nm and, upon exposure to mechanical stress or hydrophobic surfaces, disassemble into uniform fragments that remain connected by thin thread-like structures (∼2 nm). This hydrophobically induced disassembly is inhibited at enhanced electrolyte concentrations, indicating that the fragments resemble structural building blocks and the fibril integrity depends largely on hydrophobic and electrostatic interactions. Because full-length Tau and repeat domain constructs assemble into fibrils of similar thickness, the “fuzzy coat” of Tau protein termini surrounding the fibril axis is nearly invisible for atomic force microscopy and EM, presumably because of its high flexibility. PMID:20566652

Double-grooved nanofibre surfaces with enhanced anisotropic hydrophobicity.

PubMed

Liang, Meimei; Chen, Xin; Xu, Yang; Zhu, Lei; Jin, Xiangyu; Huang, Chen

2017-11-02

This study reports a facile method for fabricating double-grooved fibrous surfaces. The primary grooves of the surface are formed by aligned fibres, while the secondary grooves are achieved by oriented nanogrooves on the fibre surface. Investigation into the formation mechanism reveals that the nanogrooves can be readily tailored through adjusting the solvent ratio and relative humidity. With this understanding, a variety of polymers have been successfully electrospun into fibres having the same nanogrooved feature. These fibres show high resemblance to natural hierarchical structures, and thereby endowing the corresponding double-grooved surface with enhanced anisotropic hydrophobicity. A water droplet at a parallel direction to the grooves exhibits a much higher contact angle and a lower roll-off angle than the droplet at a perpendicular direction. The application potential of such anisotropic hydrophobicity has been demonstrated via a fog collection experiment, in which the double-grooved surface can harvest the largest amount of water. Moreover, the fabrication method requires neither post-treatment nor sophisticated equipment, making us anticipate that the double-grooved surface would be competitive in areas where a highly ordered surface, a large surface area and an anisotropic hydrophobicity are preferred.

The Coming and Going of Ice

NASA Image and Video Library

2015-12-10

Like Earth's water table, Mars has an ice table. Sometimes, the ice table coincides with the ground's surface as it does here. The knobby, pitted terrain is caused when ice is deposited and then sublimates over and over again. This geologic process is called "accrescence" and "decrescence" and also occurs on Neptune's moon Triton and on Pluto, though in the outer Solar System the ice is not water ice. Other evidence for ice here includes the rope-like, curved flow feature that resembles glacial flow. Solis Planum -- a huge mound south of Valles Marineris -- is the location of this image. http://photojournal.jpl.nasa.gov/catalog/PIA20208

Lymphatic endothelial cell line (CH3) from a recurrent retroperitoneal lymphangioma.

PubMed

Way, D; Hendrix, M; Witte, M; Witte, C; Nagle, R; Davis, J

1987-09-01

An endothelial cell line derived from a massive recurrent chyle-containing retroperitoneal lymphangioma was isolated in monolayer culture. Scanning and transmission electron microscopy and immunohistochemistry confirmed a close resemblance to blood vascular endothelium with typical cobblestone morphology, positive immunofluorescence staining for endothelial marker Factor VIII-associated antigen and fibronectin, and prominent Weibel-Palade bodies. The endothelial cells also exhibited other ultrastructural features characteristic of lymphatic endothelium, including sparse microvillous surface projections, overlapping intercellular junctions, and abundant intermediate filaments. This endothelial cell line represents a new source of proliferating lymphatic endothelium for future study, including structural and functional comparison to blood vascular endothelium.

Titan's Exotic Weather

NASA Astrophysics Data System (ADS)

Griffith, Caitlin A.

2006-09-01

Images of Titan, taken during the joint NASA and European Space Agency Cassini-Huygens mission, invoke a feeling of familiarity: washes wind downhill to damp lakebeds; massive cumuli form and quickly dissipate, suggestive of rain; and dark oval regions resemble lakes. These features arise from Titan's unique similarity with Earth: both cycle liquid between their surfaces and atmospheres, but in Titan's cool atmosphere it is methane that exists as a gas, liquid, and ice. While Titan enticingly resembles Earth, its atmosphere is 10 times thicker, so that its radiative time constant near the surface exceeds a Titan year, and prohibits large thermal gradients and seasonal surface temperature variations exceeding 3K. Titan also lacks oceans - central to Earth's climate - and instead stores much of its condensible in its atmosphere. As a result, Titan's weather differs remarkably from Earth's. Evidence for this difference appears in the location of Titan's large clouds, which frequent a narrow band at 40S latitude and a region within 30 latitude of the S. Pole. Ground-based and Cassini observations, combined with thermodynamic considerations, indicate that we are seeing large convective cloud systems. Detailed cloud models and general circulation models further suggest that these are severe rain storms, which will migrate with the change in season. Outside these migrating "gypsy" cloud bands, the atmosphere appears to be calm, humid and thus frequented by thin stratiform clouds. An intriguingly alien environment is predicted. Yet, the combined effects of Titan's patchy wet surface, atmospheric tides, possible ice volcanoes, and detailed seasonal variations remain unclear as we have witnessed only one season so far. This talk will review observations of Titan's lower atmosphere and modeling efforts to explain the observations, and explore the questions that still elude us.

Initiation of Martian Outflow Channels: Related to the Dissociation of Gas Hydrate?

NASA Technical Reports Server (NTRS)

Max, Michael D.; Clifford, Stephen M.

2001-01-01

We propose that the disruption of subpermafrost aquifers on Mars by the thermal- or pressure-induced dissociation of methane hydrate may have been a frequent trigger for initiating outflow channel activity. This possibility is raised by recent work that suggests that significant amounts of methane and gas hydrate may have been produced within and beneath the planet's cryosphere. On Earth, the build-up of overpressured water and gas by the decomposition of hydrate deposits has been implicated in the formation of large blowout features on the ocean floor. These features display a remarkable resemblance (in both morphology and scale) to the chaotic terrain found at the source of many Martian channels. The destabilization of hydrate can generate pressures sufficient to disrupt aquifers confined by up to 5 kilometers of frozen ground, while smaller discharges may result from the water produced by the decomposition of near-surface hydrate alone.

Release of volatiles from a possible cryovolcano from near-infrared imaging of Titan

USGS Publications Warehouse

Sotin, Christophe; Jaumann, R.; Buratti, B.J.; Brown, R.H.; Clark, R.N.; Soderblom, L.A.; Baines, K.H.; Bellucci, G.; Bibring, J.-P.; Capaccioni, F.; Cerroni, P.; Combes, M.; Coradini, A.; Cruikshank, D.P.; Drossart, P.; Formisano, V.; Langevin, Y.; Matson, D.L.; McCord, T.B.; Nelson, R.M.; Nicholson, P.D.; Sicardy, B.; Lemouelic, S.; Rodriguez, S.; Stephan, K.; Scholz, C.K.

2005-01-01

Titan is the only satellite in our Solar System with a dense atmosphere. The surface pressure is 1.5 bar (ref. 1) and, similar to the Earth, N 2 is the main component of the atmosphere. Methane is the second most important component, but it is photodissociated on a timescale of 10 years (ref. 3). This short timescale has led to the suggestion that Titan may possess a surface or subsurface reservoir of hydrocarbons to replenish the atmosphere. Here we report near-infrared images of Titan obtained on 26 October 2004 by the Cassini spacecraft. The images show that a widespread methane ocean does not exist; subtle albedo variations instead suggest topographical variations, as would be expected for a more solid (perhaps icy) surface. We also find a circular structure ???30 km in diameter that does not resemble any features seen on other icy satellites. We propose that the structure is a dome formed by upwelling icy plumes that release methane into Titan's atmosphere.

Release of volatiles from a possible cryovolcano from near-infrared imaging of Titan.

PubMed

Sotin, C; Jaumann, R; Buratti, B J; Brown, R H; Clark, R N; Soderblom, L A; Baines, K H; Bellucci, G; Bibring, J-P; Capaccioni, F; Cerroni, P; Combes, M; Coradini, A; Cruikshank, D P; Drossart, P; Formisano, V; Langevin, Y; Matson, D L; McCord, T B; Nelson, R M; Nicholson, P D; Sicardy, B; LeMouelic, S; Rodriguez, S; Stephan, K; Scholz, C K

2005-06-09

Titan is the only satellite in our Solar System with a dense atmosphere. The surface pressure is 1.5 bar (ref. 1) and, similar to the Earth, N2 is the main component of the atmosphere. Methane is the second most important component, but it is photodissociated on a timescale of 10(7) years (ref. 3). This short timescale has led to the suggestion that Titan may possess a surface or subsurface reservoir of hydrocarbons to replenish the atmosphere. Here we report near-infrared images of Titan obtained on 26 October 2004 by the Cassini spacecraft. The images show that a widespread methane ocean does not exist; subtle albedo variations instead suggest topographical variations, as would be expected for a more solid (perhaps icy) surface. We also find a circular structure approximately 30 km in diameter that does not resemble any features seen on other icy satellites. We propose that the structure is a dome formed by upwelling icy plumes that release methane into Titan's atmosphere.

Generation of 3-D surface maps in waste storage silos using a structured light source

NASA Technical Reports Server (NTRS)

Burks, B. L.; Rowe, J. C.; Dinkins, M. A.; Christensen, B.; Selleck, C.; Jacoboski, D.; Markus, R.

1992-01-01

Surface contours inside the large waste storage tanks typical of the Department of Energy (DOE) complex are, in general, highly irregular. In addition to pipes and other pieces of equipment in the tanks, the surfaces may have features such as mounds, fissures, crystalline structures, and mixed solid and liquid forms. Prior to remediation activities, it will be necessary to characterize the waste to determine the most effective remediation approaches. Surface contour data will be required both prior to and during remediation. The use is described of a structured light source to generate 3-D surface contour maps of the interior of waste storage silos at the Feed Materials Production Center at Fernald, OH. The landscape inside these large waste storage tanks bears a strong resemblance to some of the landscapes that might be encountered during lunar or planetary exploration. Hence, these terrestrial 3-D mapping techniques may be directly applicable to extraterrestrial exploration. In further development, it will be demonstrated that these 3-D data can be used for robotic task planning just as 3-D surface contour data of a satellite could be used to plan maintenance tasks for a space-based servicing robot.

Munitions integrity and corrosion features observed during the HUMMA deep-sea munitions disposal site investigations

NASA Astrophysics Data System (ADS)

Silva, Jeff A. K.; Chock, Taylor

2016-06-01

An evaluation of the current condition of sea-disposed military munitions observed during the 2009 Hawaii Undersea Military Munitions Assessment Project investigation is presented. The 69 km2 study area is located south of Pearl Harbor, Oahu, Hawaii, and is positioned within a former deep-sea disposal area designated as Hawaii-05 or HI-05 by the United States Department of Defense. HI-05 is known to contain both conventional and chemical munitions that were sea-disposed between 1920 and 1951. Digital images and video reconnaissance logs collected during six remotely operated vehicle and 16 human-occupied vehicle surveys were used to classify the integrity and state of corrosion of the 1842 discarded military munitions (DMM) objects encountered. Of these, 5% (or 90 individual DMM objects) were found to exhibit a mild-moderate degree of corrosion. The majority (66% or 1222 DMM objects) were observed to be significantly corroded, but visually intact on the seafloor. The remaining 29% of DMM encountered were found to be severely corroded and breached, with their contents exposed. Chemical munitions were not identified during the 2009 investigation. In general, identified munitions known to have been constructed with thicker casings were better preserved. Unusual corrosion features were also observed, including what are termed here as 'corrosion skirts' that resembled the flow and cementation of corrosion products at and away from the base of many munitions, and 'corrosion pedestal' features resembling a combination of cemented corrosion products and seafloor sediments that were observed to be supporting munitions above the surface of the seafloor. The origin of these corrosion features could not be determined due to the lack of physical samples collected. However, a microbial-mediated formation hypothesis is presented, based on visual analysis, which can serve as a testable model for future field programs.

ARC-1989-A89-7025

NASA Image and Video Library

1989-08-24

P-34687 Range : 530,000 km. ( 330,000 miles ) Smallest Resolvable Feature : 10 km or 6 miles This Voyager 2 image of Neptune's satellite Triton shows the first photo of Triton to reveal surface topography. The south pole, continuously illuminated by sunlight at this season, ia at bottom left. the boundary between bright southern hemisphere and the darker and the darker, northern hemisphere is clearly visible. Both the darker regions to the north and the very bright sub-equatorial band show a complex pattern of irregular topography that somewhat resembles 'fretted terrain' on parts of Venus and Mars. The pattern of dark and light regions over most of the southern hemisphere will require higher resolution images for interpretation. Also evident are long, straight lines that appear to be surface expressions of internal, tectonic processes. No large impact ctaters are visible, suggesting that the crust of Triton has been renewed relatively recently, that is, within the last bllion years or less.

Pattern formation with proportionate growth

NASA Astrophysics Data System (ADS)

Dhar, Deepak

It is a common observation that as baby animals grow, different body parts grow approximately at same rate. This property, called proportionate growth is remarkable in that it is not encountered easily outside biology. The models of growth that have been studied in Physics so far, e.g diffusion -limited aggregation, surface deposition, growth of crystals from melt etc. involve only growth at the surface, with the inner structure remaining frozen. Interestingly, patterns formed in growing sandpiles provide a very wide variety of patterns that show proportionate growth. One finds patterns with different features, with sharply defined boundaries. In particular, even with very simple rules, one can produce patterns that show striking resemblance to those seen in nature. We can characterize the asymptotic pattern exactly in some special cases. I will discuss in particular the patterns grown on noisy backgrounds. Supported by J. C. Bose fellowship from DST (India).

Mechanical Properties of a vdW molecular monolayer at a metal surface: Structural Polymorphism leading to facile compression

NASA Astrophysics Data System (ADS)

Sun, Dezheng; Kim, Daeho; Le, Duy; Borck, Øyvind; Berland, Kristian; Kim, Kwangmoo; Lu, Wenhao; Zhu, Yeming; Luo, Miaomiao; Wyrick, Jon; Cheng, Zhihai; Einstein, T. L.; Rahman, Talat; Hyldgaard, Per; Bartels, Ludwig

2011-03-01

Intermolecular force plays an important role in self-assembly and surface pattern formation. Anthracene and similar unsubstituted arenes attach to a metallic substrate predominantly through van der Waals interaction leading. In this contribution we present images how anthracene on Cu(111) forms a large number of highly ordered patterns that feature a broad array of structural motifs. Density functional theory modeling including vdW interactions allows us to model the energetic of the pattern formation at high fidelity. Moreover, it allows us to deduce the strain energy associated with films of varying coverage. From this work, we obtain the Young's modulus and Poisson Ratio of a molecular monolayer, which resemble properties conventionally found for porous materials. These patterns are in marked contrast to those found after introduction of functional groups in the molecules, such as carbonyls or thiols.

Mass movements on Venus - Preliminary results from Magellan cycle 1 observations

NASA Technical Reports Server (NTRS)

Malin, Michael C.

1992-01-01

A preliminary assessment of mass movements and their geomorphic characteristics as determined from visual inspection of Magellan cycle 1 synthetic aperture radar images is described. The primary data set was a catalog of over 200 ten-inch square photographic prints of full-resolution mosaic image data records. Venus exhibits unambiguous evidence of mass movements at a variety of scales. Mass movements appear mostly in the form of block and rock movements; there is little evidence of regolith and sediment movements. Unique Venusian conditions may play a role in the creation of some mass movement features. Dark (smooth) surfaces surrounding many rockslide avalanches are probably fine materials emplaced as part of the mass movement process, as airfall, surface-hugging density flows, or coarse-depleted debris flows. The size and efficiency of emplacement of landslide deposits on Venus are comparable to those seen on Mars, which in turn generally resemble terrestrial occurrences.

Numerical modeling of the thin shallow solar dynamo

NASA Astrophysics Data System (ADS)

O'Bryan, J. B.; Jarboe, T. R.

2017-10-01

Nonlinear, numerical computation with the NIMROD code is used to explore and validate the thin shallow solar dynamo model [T.R. Jarboe et al. 2017], which explains the observed global temporal evolution (e.g. magnetic field reversal) and local surface structures (e.g. sunspots) of the sun. The key feature of this model is the presence and magnetic self-organization of global magnetic structures (GMS) lying just below the surface of the sun, which resemble 1D radial Taylor states of size comparable to the supergranule convection cells. First, we seek to validate the thin shallow solar dynamo model by reproducing the 11 year timescale for reversal of the solar magnetic field. Then, we seek to model formation of GMS from convection zone turbulence. Our computations simulate a slab covering a radial depth 3Mm and include differential rotation and gravity. Density, temperature, and resistivity profiles are taken from the Christensen-Dalsgaard model.

Chang'e-2 spacecraft observations of asteroid 4179 Toutatis

NASA Astrophysics Data System (ADS)

Ji, Jianghui; Jiang, Yun; Zhao, Yuhui; Wang, Su; Yu, Liangliang

2016-01-01

On 13 December 2012, Chang'e-2 completed a successful flyby of the near-Earth asteroid 4179 Toutatis at a closest distance of 770 meters from the asteroid's surface. The observations show that Toutatis has an irregular surface and its shape resembles a ginger-root of a smaller lobe (head) and a larger lobe (body). Such bilobate shape is indicative of a contact binary origin for Toutatis. In addition, the high-resolution images better than 3 meters provide a number of new discoveries about this asteroid, such as an 800-meter depression at the end of the large lobe, a sharply perpendicular silhouette near the neck region, boulders, indicating that Toutatis is probably a rubble-pile asteroid. Chang'e-2 observations have significantly revealed new insights into the geological features and the formation and evolution of this asteroid. In final, we brief the future Chinese asteroid mission concept.

What Lies Beneath: Surface Patterns of Glacier-Like Landforms

NASA Image and Video Library

2016-09-21

The rotational axis of Mars is currently tilted by about 25 degrees, very similar to that of the Earth (at 23.4 degrees). However, while Earth's axial tilt (also known as "obliquity") tends to change very slightly over time (almost 3 degrees in 40,000 year-cycles), the obliquity of Mars is much more chaotic and varies widely from 0 to almost 60 degrees! The fact that it is currently similar to that of the Earth is merely a coincidence. Currently, water-ice is stable on the Martian surface only in the polar regions. However, during times of "high obliquity," that stability shifts towards the equatorial regions. We see evidence for recent periods of high obliquity on Mars in the form of features common in the mid-latitude regions, which planetary scientists call "viscous flow features," "lobate debris aprons," or "lineated valley fills." These are all scientifically conservative ways of describing features on Mars that resemble mountain glaciers on Earth. We now know from radar observations, particularly using the SHARAD instrument on board the Mars Reconnaissance Orbiter, that these features are really composed of mixtures of pure ice and dust, and as a result, many scientists have started using the term "glacier-like forms" (GLF) to describe some of them. The main reason that these feature are still present for us to observe nowadays-despite the inhospitable conditions for water ice in these latitudes-is that these "glaciers" are covered by thin layers of dust, which protect them from the atmosphere of Mars and prevents, or significantly slows down, the loss of ice through sublimation to the atmosphere. However, if we were to take a look at this image of a "lobate debris apron," we will see that some areas show numerous depressions, which suggests that these areas have lost some of the ice creating these "deflation features." In addition, if we zoom in on one of these depressions, we will see surface polygonal patterns, which are common in cold regions on Earth (such as Alaska, northern Canada, and Siberia) and are indicators of shallow sub-surface water-ice. http://photojournal.jpl.nasa.gov/catalog/PIA21065

Environment modelling in near Earth space: Preliminary LDEF results

NASA Technical Reports Server (NTRS)

Coombs, C. R.; Atkinson, D. R.; Wagner, J. D.; Crowell, L. B.; Allbrooks, M.; Watts, A. J.

1992-01-01

Hypervelocity impacts by space debris cause not only local cratering or penetrations, but also cause large areas of damage in coated, painted or laminated surfaces. Features examined in these analyses display interesting morphological characteristics, commonly exhibiting a concentric ringed appearance. Virtually all features greater than 0.2 mm in diameter possess a spall zone in which all of the paint was removed from the aluminum surface. These spall zones vary in size from approximately 2 - 5 crater diameters. The actual craters in the aluminum substrate vary from central pits without raised rims, to morphologies more typical of craters formed in aluminum under hypervelocity laboratory conditions for the larger features. Most features also possess what is referred to as a 'shock zone' as well. These zones vary in size from approximately 1 - 20 crater diameters. In most cases, only the outer-most layer of paint was affected by this impact related phenomenon. Several impacts possess ridge-like structures encircling the area in which this outer-most paint layer was removed. In many ways, such features resemble the lunar impact basins, but on an extremely reduced scale. Overall, there were no noticeable penetrations, bulges or spallation features on the backside of the tray. On Row 12, approximately 85 degrees from the leading edge (RAM direction), there was approximately one impact per 15 cm(exp 2). On the trailing edge, there was approximately one impact per 72 cm(exp 2). Currently, craters on four aluminum experiment trays from Bay E09, directly on the leading edge are being measured and analyzed. Preliminary results have produced more than 2200 craters on approximately 1500 cm(exp 2) - or approximately 1 impact per 0.7 cm(exp 2).

Investigations of morphological features of picosecond dual-wavelength laser ablation of stainless steel

NASA Astrophysics Data System (ADS)

Zhao, Wanqin; Wang, Wenjun; Mei, Xuesong; Jiang, Gedong; Liu, Bin

2014-06-01

Investigations on the morphological features of holes and grooves ablated on the surface of stainless steel using the picosecond dual-wavelength laser system with different powers combinations are presented based on the scarce researches on morphology of dual-wavelength laser ablation. The experimental results show the profiles of holes ablated by the visible beam appear V-shaped while those for the near-infrared have large openings and display U-shaped, which are independent of the ablation mechanism of ultrafast laser. For the dual-wavelength beam (a combination of visible beam and near-infrared), the holes resemble sunflower-like structures and have smoother ring patterns on the bottom. In general, the holes ablated by the dual-wavelength beam appear to have much flatter bottoms, linearly sloped side-walls and spinodal structures between the bottoms of the holes and the side-walls. Furthermore, through judiciously combining the powers of the dual-wavelength beam, high-quality grooves could be obtained with a flat worm-like structure at the bottom surface and less resolidified melt ejection edges. This study provides insight into optimizing ultrafast laser micromachining in order to obtain desired morphology.

Interesting Features in Spirit's Uphill View

NASA Technical Reports Server (NTRS)

2004-01-01

Planetary scientists got excited when they saw this imagery coming in from NASA's Mars Exploration Rover Spirit because they could see hints of rock strata and other interesting geologic features ahead. In the middle of this image, from upper left to the lower right, lies a trough that resembles a small ravine. To the right of that and a little way up the hill, beyond a rock-strewn surface, sits a small rounded ridge. Fine horizontal streaks, just perceptible in this image, suggest possible layering in the bedrock. Above that are rock features that appear to drape across the slopes. Scientists are discussing whether to take the rover closer or select other interesting targets for further study. This view looks eastward from the 'West Spur' of the 'Columbia Hills,' where Spirit has been conducting scientific investigations. It is a mosaic of several frames Spirit took with its panoramic camera on the rover's 229th martian day, or sol, (Aug. 24, 2004). The field of view is 48 degrees from left to right. The image is presented in a cylindrical projection with geometrical seam correction.

Exploring the Surface of Titan with Cassini-Huygens

NASA Astrophysics Data System (ADS)

Turtle, E. P.; Barnes, J.; Buratti, B. J.; Collins, G.; Fussner, S.; Lopes, R.; Lorenz, R. D.; Lunine, J. I.; McCord, T. B.; McEwen, A. S.; Nelson, R.; Perry, J.; Porco, C. C.; Soderblom, L.; Sotin, C.; Wall, S. D.

2005-12-01

Over the past year, the Cassini-Huygens mission has returned a wealth of data about the surface of Saturn's satellite Titan. Cassini's Imaging Science Subsystem (ISS), RADAR, and Visual and Infrared Mapping Spectrometer (VIMS), and Huygens' Descent Imaging Spectral Radiometer (DISR) have revealed an intriguing surface that is at once familiar and alien. Although water-ice and liquid hydrocarbons play the roles that rock and water play on Earth, the surface appears to have been worked by a wide variety of processes resulting in a seemingly Earth-like balance of fluvial, aeolian, and volcanic features, with relatively few impact craters. There seem to be at least two classes of surface material: dark areas (at visible-IR wavelengths) that are spectrally consistent with contaminated water ice, and brighter areas of unknown composition which show greater variations. The expected bodies of liquids have yet to be definitively identified; however, circumstantial evidence for liquids having acted upon the surface in Titan's past is abundant, primarily in the form of channels, and possible ponds or lakes, which have been observed by multiple instruments. Other features suggest that wind redistributes some surface materials, most likely the detritus of the complex atmospheric chemistry, creating diffuse IR-bright deposits and long, narrow, radar-dark (2.2-cm) stripes, all of which trend generally east-west. Only two impact structures have been identified to date, although several other suspiciously circular features have been documented. A variety of the morphologies observed bear strong resemblances to volcanic structures. A number of other features remain mysterious and further co-analysis of these data sets, as well as the anticipated acquisition of more data, will be needed to fully understand the nature of Titan's surface, the albedo variations observed at different wavelengths, and the processes that have acted upon it (and may continue to). In addition to the Huygens descent, the Cassini orbiter has observed Titan on six close passes to date, and two more are planned for Fall 2005 which will increase both the spatial coverage, at various wavelengths, and the time base over which observations have been made as northern-hemisphere spring approaches. We will present observations of Titan's surface acquired by the complementary suite of instruments on board Cassini-Huygens, the combination of which is proving essential to interpreting Titan's geology.

Landslides on Ceres

NASA Image and Video Library

2017-04-19

NASA's Dawn spacecraft has revealed many landslides on Ceres, which researchers interpret to have been shaped by a significant amount of water ice. A 2017 study in the journal Nature Geoscience classifies three types of these debris flows. Image 1 (left in the montage) shows an example of "Type I" flow features, which are relatively round and large, have thick "toes" at their ends. They look similar to rock glaciers and icy landslides on Earth. Type I landslides are mostly found at high latitudes, which is also where the most ice is thought to reside near Ceres' surface. Image 2 (center) shows an example of a "Type II" flow feature. Type II features are often thinner and longer than Type I, and are the most common type of landslide on Ceres. They appear more like the avalanches seen on Earth. Image 3 (right) shows an example of a "Type III" flow feature at Datan Crater. The study authors interpret Ceres' Type III landslides to involve melted ice, although scientists do not know if they actually contain liquid water. The authors think Type III landslides are related to impact craters, and may have formed during impact events into the ice on Ceres. The features resemble fluid material ejected from craters in the icy regions of Mars and Jupiter's moon Ganymede. https://photojournal.jpl.nasa.gov/catalog/PIA21471

Effect of Alkali-Acid-Heat Chemical Surface Treatment on Electron Beam Melted Porous Titanium and Its Apatite Forming Ability

PubMed Central

Bsat, Suzan; Amin Yavari, Saber; Munsch, Maximilian; Valstar, Edward R.; Zadpoor, Amir A.

2015-01-01

Advanced additive manufacturing techniques such as electron beam melting (EBM), can produce highly porous structures that resemble the mechanical properties and structure of native bone. However, for orthopaedic applications, such as joint prostheses or bone substitution, the surface must also be bio-functionalized to promote bone growth. In the current work, EBM porous Ti6Al4V alloy was exposed to an alkali acid heat (AlAcH) treatment to bio-functionalize the surface of the porous structure. Various molar concentrations (3, 5, 10M) and immersion times (6, 24 h) of the alkali treatment were used to determine optimal parameters. The apatite forming ability of the samples was evaluated using simulated body fluid (SBF) immersion testing. The micro-topography and surface chemistry of AlAcH treated samples were evaluated before and after SBF testing using scanning electron microscopy and energy dispersive X-ray spectroscopy. The AlAcH treatment successfully modified the topographical and chemical characteristics of EBM porous titanium surface creating nano-topographical features ranging from 200–300 nm in size with a titania layer ideal for apatite formation. After 1 and 3 week immersion in SBF, there was no Ca or P present on the surface of as manufactured porous titanium while both elements were present on all AlAcH treated samples except those exposed to 3M, 6 h alkali treatment. An increase in molar concentration and/or immersion time of alkali treatment resulted in an increase in the number of nano-topographical features per unit area as well as the amount of titania on the surface. PMID:28788021

Effect of Alkali-Acid-Heat Chemical Surface Treatment on Electron Beam Melted Porous Titanium and Its Apatite Forming Ability.

PubMed

Bsat, Suzan; Yavari, Saber Amin; Munsch, Maximilian; Valstar, Edward R; Zadpoor, Amir A

2015-04-08

Advanced additive manufacturing techniques such as electron beam melting (EBM), can produce highly porous structures that resemble the mechanical properties and structure of native bone. However, for orthopaedic applications, such as joint prostheses or bone substitution, the surface must also be bio-functionalized to promote bone growth. In the current work, EBM porous Ti6Al4V alloy was exposed to an alkali acid heat (AlAcH) treatment to bio-functionalize the surface of the porous structure. Various molar concentrations (3, 5, 10M) and immersion times (6, 24 h) of the alkali treatment were used to determine optimal parameters. The apatite forming ability of the samples was evaluated using simulated body fluid (SBF) immersion testing. The micro-topography and surface chemistry of AlAcH treated samples were evaluated before and after SBF testing using scanning electron microscopy and energy dispersive X-ray spectroscopy. The AlAcH treatment successfully modified the topographical and chemical characteristics of EBM porous titanium surface creating nano-topographical features ranging from 200-300 nm in size with a titania layer ideal for apatite formation. After 1 and 3 week immersion in SBF, there was no Ca or P present on the surface of as manufactured porous titanium while both elements were present on all AlAcH treated samples except those exposed to 3M, 6 h alkali treatment. An increase in molar concentration and/or immersion time of alkali treatment resulted in an increase in the number of nano-topographical features per unit area as well as the amount of titania on the surface.

Molecular-orbital models for the catalytic activity and selectivity of coordinatively unsaturated platinum surfaces and complexes

NASA Astrophysics Data System (ADS)

Balazs, A. C.; Johnson, K. H.

1982-01-01

Electronic structures have been calculated for 5-, 6-, and 10-atom Pt clusters, as well as for a Pt(PH 3) 4 coordination complex, using the self-consistent-field X-alpha scattered-wave (SCF-Xα-SW) molecular-orbital technique. The 10-atom cluster models the local geometry of a flat, unreconstructed Pt(100) surface, while the 5- and 6-atom clusters show features of a stepped Pt surface. Pt(PH 3) 4 resembles the chemically similar homogeneous catalyst Pt(PPh 3) 4. Common to all these coordinatively unsaturated complexes are orbitals lying near or coinciding with the highest occupied molecular orbital ("Fermi level") which show pronounced d lobes pointing directly into the vacuum. Under the hypothesis that these molecular orbitals are mainly responsible for the chemical activities of the above species, one can account for the relative similarities and differences in catalytic activity and selectivity displayed by unreconstructed Pt(100) surfaces, stepped Pt surfaces or particles, and isolated Pt(PPh 3) 4 coordination complexes. The relevance of these findings to catalyst-support interactions is also discussed. Finally, relativistic corrections to the electronic structures are calculated and their implications on catalytic properties discussed.

Time-lapse cinemicrography and scanning electron microscopy of platelet formation by megakaryocytes.

PubMed

Haller, C J; Radley, J M

1983-01-01

The surface architecture of megakaryocytes undergoing platelet formation in vitro has been examined by time-lapse cinemicrography and scanning electron microscopy. Fragments of mouse bone marrow were placed in culture medium and incubated at 37 degrees C. After several hours mature megakaryocytes migrated out of the marrow and some underwent shape changes so that they eventually appeared as a relatively small central body, housing the nucleus, from which emerged a number of thin processes which resembled platelet chains. Scanning electron microscopy showed that initially the megakaryocyte surface was ruffled but with development of processes it became smoother. Circumferential folds of small amplitude were found on the surface of developing constrictions which separated putative platelets. It is thought they may be associated with the mechanism of extension, but could have a role in establishing the topography of membrane components. Rupture of the chains and release of platelets was not observed; this permits the number of putative platelets formed by individual megakaryocytes to be determined. The putative platelets exhibited features common to circulating platelets when exposed to a glass surface including the development of pseudopodia and, eventually, flattening on to the surface.

MYONEURAL JUNCTIONS OF TWO ULTRASTRUCTURALLY DISTINCT TYPES IN EARTHWORM BODY WALL MUSCLE

PubMed Central

Rosenbluth, Jack

1972-01-01

The longitudinal muscle of the earthworm body wall is innervated by nerve bundles containing axons of two types which form two corresponding types of myoneural junction with the muscle fibers Type I junctions resemble cholinergic neuromuscular junctions of vertebrate skeletal muscle and are characterized by three features: (a) The nerve terminals contain large numbers of spherical, clear, ∼500 A vesicles plus a small number of larger dense-cored vesicles (b) The junctional gap is relatively wide (∼900 A), and it contains a basement membrane-like material, (c) The postjunctional membrane, although not folded, displays prominent specializations on both its external and internal surfaces The cytoplasmic surface is covered by a dense matrix ∼200 A thick which appears to be the site of insertion of fine obliquely oriented cytoplasmic filaments The external surface exhibits rows of projections ∼200 A long whose bases consist of hexagonally arrayed granules seated in the outer dense layer of the plasma membrane The concentration of these hexagonally disposed elements corresponds to the estimated concentration of both receptor sites and acetylcholinesterase sites at cholinergic junctions elsewhere. Type II junctions resemble the adrenergic junctions in vertebrate smooth muscle and exhibit the following structural characteristics: (a) The nerve fibers contain predominantly dense-cored vesicles ∼1000 A in diameter (b) The junctional gap is relatively narrow (∼150 A) and contains no basement membrane-like material, (c) Postjunctional membrane specialization is minimal. It is proposed that the structural differences between the two types of myoneural junction reflect differences in the respective transmitters and corresponding differences in the mechanisms of transmitter action and/or inactivation. PMID:5044759

Spectral Emissivity (6 - 38 µm) of Jupiter's Trojan Asteroids

NASA Astrophysics Data System (ADS)

Martin, Audrey; Emery, Joshua P.; Lindsay, Sean S.

2016-10-01

Jovian Trojan asteroids, located in Jupiter's stable Lagrange points, are an extensive population of primitive bodies in the Solar System. Previous work in the visible and NIR shows Trojans have featureless, red-sloped spectra and low albedos, making mineralogical characterization difficult. However, it has been shown that three Trojans exhibit silicate emissivity features in the thermal IR (6 - 38 μm Emery et al. 2006, Icarus 182). The detected features indicate the presence of fine-grained (micron-sized) silicate dust on the surfaces, and closely resemble spectral features measured of cometary comae. We hypothesize that Trojan surface mineralogy is fairly uniform and is similar to comet dust. The principal goal of this work is, therefore, to derive primary surface mineralogy from thermal emission spectra. We present thermal IR spectra of 12 Trojans observed with NASA's Spitzer space telescope, using the InfraRed Spectrograph (IRS) in Staring Mode from June 2006 to June 2007. Eight objects were observed over the 5.2 - 38 µm spectral range, and four objects over the 7.5 - 38 µm range. Using the NEATM thermal model, we have computed size, albedo, and beaming parameter for the 12 Trojans. Results for these physical parameters are comparable to those derived from WISE data (Grav et al. 2011, ApJ 742 (1); Grav et al. 2012, ApJ 759 (49)). There are, however, some discrepancies, especially with 2797 Teucer. The emissivity spectra fall into groups that directly correlate with the red and less-red spectral slope groupings described in Emery et al. (2011, ApJ, 141(1)). Strong 10 µm emission features appear in each object, suggesting the presence of fine-grained silicates. Features found between 12-13 µm, and 18-19 µm are also observed in all spectra. We will present these new Trojan asteroid data with mineralogical estimates derived from the emissivity spectra.

Venus - 3D Perspective View of Latona Corona and Dali Chasma

NASA Technical Reports Server (NTRS)

1992-01-01

This computer-generated perspective view of Latona Corona and Dali Chasma on Venus shows Magellan radar data superimposed on topography. The view is from the northeast and vertical exaggeration is 10 times. Exaggeration of relief is a common tool scientists use to detect relationships between structure (i.e. faults and fractures) and topography. Latona Corona, a circular feature approximately 1,000 kilometers (620 miles) in diameter whose eastern half is shown at the left of the image, has a relatively smooth, radar-bright raised rim. Bright lines or fractures within the corona appear to radiate away from its center toward the rim. The rest of the bright fractures in the area are associated with the relatively deep (approximately 3 kilometers or 1.9 miles) troughs of Dali Chasma. The Dali and Diana Chasma system consist of deep troughs that extend for 7,400 kilometers (4,588 miles) and are very distinct features on Venus. Those chasma connect the Ovda and Thetis highlands with the large volcanoes at Atla Regio and thus are considered to be the 'Scorpion Tail' of Aphrodite Terra. The broad, curving scarp resembles some of Earth's subduction zones where crustal plates are pushed over each other. The radar-bright surface at the highest elevation along the scarp is similar to surfaces in other elevated regions where some metallic mineral such as pyrite (fool's gold) may occur on the surface.

Solid-State Photochemistry as a Formation Mechanism for Titan's Stratospheric C4N2 Ice Clouds

NASA Technical Reports Server (NTRS)

Anderson, C. M.; Samuelson, R. E.; Yung, Y. L.; McLain, J. L.

2016-01-01

We propose that C4N2 ice clouds observed in Titan's springtime polar stratosphere arise due to solid-state photochemistry occurring within extant ice cloud particles of HCN-HC3N mixtures. This formation process resembles the halogen-induced ice particle surface chemistry that leads to condensed nitric acid trihydrate (NAT) particles and ozone depletion in Earth's polar stratosphere. As our analysis of the Cassini Composite Infrared Spectrometer 478 per centimeter ice emission feature demonstrates, this solid-state photochemistry mechanism eliminates the need for the relatively high C4N2 saturation vapor pressures required (even though they are not observed) when the ice is produced through the usual procedure of direct condensation from the vapor.

Weld radiograph enigmas

NASA Technical Reports Server (NTRS)

Jemian, Wartan A.

1986-01-01

Weld radiograph enigmas are features observed on X-ray radiographs of welds. Some of these features resemble indications of weld defects, although their origin is different. Since they are not understood, they are a source of concern. There is a need to identify their causes and especially to measure their effect on weld mechanical properties. A method is proposed whereby the enigmas can be evaluated and rated, in relation to the full spectrum of weld radiograph indications. Thie method involves a signature and a magnitude that can be used as a quantitive parameter. The signature is generated as the diference between the microdensitometer trace across the radiograph and the computed film intensity derived from a thickness scan along the corresponding region of the sample. The magnitude is the measured difference in intensity between the peak and base line values of the signature. The procedure is demonstated by comparing traces across radiographs of a weld sample before and after the introduction of a hole and by a system based on a MacIntosh mouse used for surface profiling.

Molecular resolution friction microscopy of Cu phthalocyanine thin films on dolomite (104) in water

NASA Astrophysics Data System (ADS)

Nita, Paweł; Pimentel, Carlos; Luo, Feng; Milián-Medina, Begoña; Gierschner, Johannes; Pina, Carlos M.; Gnecco, Enrico

2014-06-01

The reliability of ultrathin organic layers as active components for molecular electronic devices depends ultimately on an accurate characterization of the layer morphology and ability to withstand mechanical stresses on the nanoscale. To this end, since the molecular layers need to be electrically decoupled using thick insulating substrates, the use of AFM becomes mandatory. Here, we show how friction force microscopy (FFM) in water allows us to identify the orientation of copper(ii)phthalocyanine (CuPc) molecules previously self-assembled on a dolomite (104) mineral surface in ultra-high vacuum. The molecular features observed in the friction images show that the CuPc molecules are stacked in parallel rows with no preferential orientation with respect to the dolomite lattice, while the stacking features resemble well the single CuPc crystal structure. This proves that the substrate induction is low and makes friction force microscopy in water a suitable alternative to more demanding dynamic AFM techniques in ultra-high vacuum.

Molecular resolution friction microscopy of Cu phthalocyanine thin films on dolomite (104) in water.

PubMed

Nita, Paweł; Pimentel, Carlos; Luo, Feng; Milián-Medina, Begoña; Gierschner, Johannes; Pina, Carlos M; Gnecco, Enrico

2014-07-21

The reliability of ultrathin organic layers as active components for molecular electronic devices depends ultimately on an accurate characterization of the layer morphology and ability to withstand mechanical stresses on the nanoscale. To this end, since the molecular layers need to be electrically decoupled using thick insulating substrates, the use of AFM becomes mandatory. Here, we show how friction force microscopy (FFM) in water allows us to identify the orientation of copper(ii)phthalocyanine (CuPc) molecules previously self-assembled on a dolomite (104) mineral surface in ultra-high vacuum. The molecular features observed in the friction images show that the CuPc molecules are stacked in parallel rows with no preferential orientation with respect to the dolomite lattice, while the stacking features resemble well the single CuPc crystal structure. This proves that the substrate induction is low and makes friction force microscopy in water a suitable alternative to more demanding dynamic AFM techniques in ultra-high vacuum.

Large Erosional Features on the Cascadia Accretionary Wedge Imaged with New High-Resolution Multibeam Bathymetry and Seismic Datasets

NASA Astrophysics Data System (ADS)

Beeson, J. W.; Goldfinger, C.

2013-12-01

Utilizing new high resolution multibeam bathymetric data along with chirp sub-bottom and multichannel seismic reflection (MCS) data, we identified remarkable erosional features on the toe of the Cascadia accretionary wedge near Willapa Canyon, offshore Washington, USA. Bathymetric data was compiled from the Cascadia Open-Access Seismic Transects (COAST) cruise and from the site survey cruise for the Cascadia Initiative. These features loosely resemble slope failures of the frontal thrust, but can be distinguished from such failures by several key features: They incise the crest of the frontal thrust and encompass the landward limb; They have floors below the level of the abyssal plain, similar to plunge pool morphology; They show no evidence of landslide blocks at the base of the slope indicative of block sliding. The features where likely formed during the latest Pleistocene based on post event deposition, cross-cutting relationships with Juan de Fuca Channel and the Willapa Channel levees and wave field, and post event slip on the frontal thrust of the Cascadia accretionary prism. The Holocene levees of both Willapa Channel and Juan de Fuca Channel overlap these older features, and clearly place an upper bound on the age of the erosional features in the latest Pleistocene. A lower bound is estimated from a sub-bottom profile that images ~30 meters of post scour sediment fill. Using existing literature of Holocene and Pleistocene sedimentation rates we estimate a lower age bound between ~23,000 - 56,000 y.b.p. We also map a fault scarp within the erosional feature, with ~60 m of vertical offset. Using multi-channel seismic reflection profiles from the COAST cruise we interpret this scarp as the surface expression of the landward vergent frontal thrust fault. The apparent short duration of the erosional event along the seaward margin of the accretionary wedge, coupled with the presence of the fresh fault scarp within the erosion zone, are indicative of a dormant feature with significant time required to develop the scarp after cessation of the causative process. Based on morphology, dissimilarity with other submarine features, and available age constraints, we infer that these features were most likely formed during the glacial lake outpouring in the Pacific Northwest known as the Missoula floods which occurred 13,000-19,500 y.b.p. The features themselves bear a strong resemblance to 'coulees' formed during the same glacial events onshore, and the outpourings through Willapa Channel are consistent with previous inferences of the deposition of Missoula Flood deposits in Escanaba Trough. If this timing is correct, the slip rate along the Cascadia frontal thrust can be estimated using fault geometry and scarp height as 2.8 - 4.1 mm/yr.

Spatiotemporal Patterns of Contact Across the Rat Vibrissal Array During Exploratory Behavior

PubMed Central

Hobbs, Jennifer A.; Towal, R. Blythe; Hartmann, Mitra J. Z.

2016-01-01

The rat vibrissal system is an important model for the study of somatosensation, but the small size and rapid speed of the vibrissae have precluded measuring precise vibrissal-object contact sequences during behavior. We used a laser light sheet to quantify, with 1 ms resolution, the spatiotemporal structure of whisker-surface contact as five naïve rats freely explored a flat, vertical glass wall. Consistent with previous work, we show that the whisk cycle cannot be uniquely defined because different whiskers often move asynchronously, but that quasi-periodic (~8 Hz) variations in head velocity represent a distinct temporal feature on which to lock analysis. Around times of minimum head velocity, whiskers protract to make contact with the surface, and then sustain contact with the surface for extended durations (~25–60 ms) before detaching. This behavior results in discrete temporal windows in which large numbers of whiskers are in contact with the surface. These “sustained collective contact intervals” (SCCIs) were observed on 100% of whisks for all five rats. The overall spatiotemporal structure of the SCCIs can be qualitatively predicted based on information about head pose and the average whisk cycle. In contrast, precise sequences of whisker-surface contact depend on detailed head and whisker kinematics. Sequences of vibrissal contact were highly variable, equally likely to propagate in all directions across the array. Somewhat more structure was found when sequences of contacts were examined on a row-wise basis. In striking contrast to the high variability associated with contact sequences, a consistent feature of each SCCI was that the contact locations of the whiskers on the glass converged and moved more slowly on the sheet. Together, these findings lead us to propose that the rat uses a strategy of “windowed sampling” to extract an object's spatial features: specifically, the rat spatially integrates quasi-static mechanical signals across whiskers during the period of sustained contact, resembling an “enclosing” haptic procedure. PMID:26778990

Extensive intracranial calcification of pseudo-TORCH syndrome with features of Dandy–Walker malformation

PubMed Central

Patnaik, Ashis; Mishra, Sudhansu Sekhar; Das, Srikanta

2017-01-01

Pseudo-TORCH syndrome or congenital infection-like syndrome is a group of conditions which resemble congenital infections such as those caused by toxoplasmosis, rubella, cytomegalovirus (CMV), herpes (TORCH) group of organisms, clinico-radiologically, but serological tests are negative for the organisms. One of the variety shows features such as microcephaly, extensive intracranial calcification showing gross resemblance to congenital CMV infection, making its other name as microcephaly intracranial calcification syndrome (MICS). Dandy–Walker malformation (DWM), in addition to posterior fossa large cyst, cerebellar vermis hypoplasia, and hydrocephalus is often associated with agenesis of the corpus callosum and callosal lipomas, dysplasia of the brainstem, and cerebellar hypoplasia or dysgenesis. But radiological features of DWM with microcephaly and intracranial calcification are very unusual and have been rarely reported in the literature.[1] We report a case of infant showing clinical features suggestive of congenital CMV infection with negative serology and radiological imaging suggestive of DWM with extensive intracranial calcification. Pseudo-TORCH syndrome with radiological features of DWM is a congenital developmental abnormality. Inspite of hydrocephalus, it does not require cerebrospinal fluid (CSF) diversionary procedure due to lack of increased intracranial pressure. Conservative management for seizure disorder is the optimal therapy. PMID:28761539

Extensive intracranial calcification of pseudo-TORCH syndrome with features of Dandy-Walker malformation.

PubMed

Patnaik, Ashis; Mishra, Sudhansu Sekhar; Das, Srikanta

2017-01-01

Pseudo-TORCH syndrome or congenital infection-like syndrome is a group of conditions which resemble congenital infections such as those caused by toxoplasmosis, rubella, cytomegalovirus (CMV), herpes (TORCH) group of organisms, clinico-radiologically, but serological tests are negative for the organisms. One of the variety shows features such as microcephaly, extensive intracranial calcification showing gross resemblance to congenital CMV infection, making its other name as microcephaly intracranial calcification syndrome (MICS). Dandy-Walker malformation (DWM), in addition to posterior fossa large cyst, cerebellar vermis hypoplasia, and hydrocephalus is often associated with agenesis of the corpus callosum and callosal lipomas, dysplasia of the brainstem, and cerebellar hypoplasia or dysgenesis. But radiological features of DWM with microcephaly and intracranial calcification are very unusual and have been rarely reported in the literature.[1] We report a case of infant showing clinical features suggestive of congenital CMV infection with negative serology and radiological imaging suggestive of DWM with extensive intracranial calcification. Pseudo-TORCH syndrome with radiological features of DWM is a congenital developmental abnormality. Inspite of hydrocephalus, it does not require cerebrospinal fluid (CSF) diversionary procedure due to lack of increased intracranial pressure. Conservative management for seizure disorder is the optimal therapy.

The morphometrics of "masculinity" in human faces.

PubMed

Mitteroecker, Philipp; Windhager, Sonja; Müller, Gerd B; Schaefer, Katrin

2015-01-01

In studies of social inference and human mate preference, a wide but inconsistent array of tools for computing facial masculinity has been devised. Several of these approaches implicitly assumed that the individual expression of sexually dimorphic shape features, which we refer to as maleness, resembles facial shape features perceived as masculine. We outline a morphometric strategy for estimating separately the face shape patterns that underlie perceived masculinity and maleness, and for computing individual scores for these shape patterns. We further show how faces with different degrees of masculinity or maleness can be constructed in a geometric morphometric framework. In an application of these methods to a set of human facial photographs, we found that shape features typically perceived as masculine are wide faces with a wide inter-orbital distance, a wide nose, thin lips, and a large and massive lower face. The individual expressions of this combination of shape features--the masculinity shape scores--were the best predictor of rated masculinity among the compared methods (r = 0.5). The shape features perceived as masculine only partly resembled the average face shape difference between males and females (sexual dimorphism). Discriminant functions and Procrustes distances to the female mean shape were poor predictors of perceived masculinity.

Druggable protein interaction sites are more predisposed to surface pocket formation than the rest of the protein surface.

PubMed

Johnson, David K; Karanicolas, John

2013-01-01

Despite intense interest and considerable effort via high-throughput screening, there are few examples of small molecules that directly inhibit protein-protein interactions. This suggests that many protein interaction surfaces may not be intrinsically "druggable" by small molecules, and elevates in importance the few successful examples as model systems for improving our fundamental understanding of druggability. Here we describe an approach for exploring protein fluctuations enriched in conformations containing surface pockets suitable for small molecule binding. Starting from a set of seven unbound protein structures, we find that the presence of low-energy pocket-containing conformations is indeed a signature of druggable protein interaction sites and that analogous surface pockets are not formed elsewhere on the protein. We further find that ensembles of conformations generated with this biased approach structurally resemble known inhibitor-bound structures more closely than equivalent ensembles of unbiased conformations. Collectively these results suggest that "druggability" is a property encoded on a protein surface through its propensity to form pockets, and inspire a model in which the crude features of the predisposed pocket(s) restrict the range of complementary ligands; additional smaller conformational changes then respond to details of a particular ligand. We anticipate that the insights described here will prove useful in selecting protein targets for therapeutic intervention.

Glycosylation and immunocytochemistry of binucleate cells in pronghorn (Antilocapra Americana, Antilocapridae) shows features of both Giraffidae and Bovidae

USDA-ARS?s Scientific Manuscript database

Although the Pronghorn (Antilocapra americana) resembles an antelope, its nearest relatives are the Giraffe and Okapi. In this study we have examined the placentae of 6 pronghorns using lectin histochemistry to identify any giraffid features. Results showed that the binucleate cell (BNC) of the pla...

Episodic plate separation and fracture infill on the surface of Europa

USGS Publications Warehouse

Sullivan, R.; Greeley, R.; Homan, K.; Klemaszewski, J.; Belton, M.J.S.; Carr, M.H.; Chapman, C.R.; Tufts, R.; Head, J. W.; Pappalardo, R.; Moore, J.; Thomas, P.

1998-01-01

Images obtained by the Voyager spacecraft revealed dark, wedge-shaped bands on Europa that were interpreted as evidence that surface plates, 50- 100 km across, moved and rotated relative to each other. This implied that they may be mechanically decoupled from the interior by a layer of warm ice or liquid water. Here we report similar features seen in higher resolution images (420 metres per pixel) obtained by the Galileo spacecraft that reveal new details of wedge-band formation. In particular, the interior of one dark band shows bilateral symmetry of parallel lineaments and pit complexes which indicates that plate separation occurred in discrete episodes from a central axis. The images also show that this style of tectonic activity involved plates < 10 km across. Although this tectonic style superficially resembles aspects of similar activity on Earth, such as sea-floor spreading and the formation of ice leads in polar seas, there are significant differences in the underlying physical mechanisms: the wedge-shaped bands on Europa most probably formed when lower material (ice or water) rose to fill the fractures that widened in response to regional surface stresses.

A novel RNA binding surface of the TAM domain of TIP5/BAZ2A mediates epigenetic regulation of rRNA genes.

PubMed

Anosova, Irina; Melnik, Svitlana; Tripsianes, Konstantinos; Kateb, Fatiha; Grummt, Ingrid; Sattler, Michael

2015-05-26

The chromatin remodeling complex NoRC, comprising the subunits SNF2h and TIP5/BAZ2A, mediates heterochromatin formation at major clusters of repetitive elements, including rRNA genes, centromeres and telomeres. Association with chromatin requires the interaction of the TAM (TIP5/ARBP/MBD) domain of TIP5 with noncoding RNA, which targets NoRC to specific genomic loci. Here, we show that the NMR structure of the TAM domain of TIP5 resembles the fold of the MBD domain, found in methyl-CpG binding proteins. However, the TAM domain exhibits an extended MBD fold with unique C-terminal extensions that constitute a novel surface for RNA binding. Mutation of critical amino acids within this surface abolishes RNA binding in vitro and in vivo. Our results explain the distinct binding specificities of TAM and MBD domains to RNA and methylated DNA, respectively, and reveal structural features for the interaction of NoRC with non-coding RNA. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

Perioral dermatitis

MedlinePlus

... dermatitis URL of this page: //medlineplus.gov/ency/article/001455.htm Perioral dermatitis To use the sharing features on this page, please enable JavaScript. Perioral dermatitis is a skin disorder resembling acne ...

Desert Varnish - Preservation of Biofabrics/Implcations for Mars

NASA Technical Reports Server (NTRS)

Probst, Luke W.; Allen, Carlton C.; Thomas-Keprta, Kathie L.; Clemett, Simon J.; Longazo, Teresa G.; Nelman-Gonzalez, Mayra A.; Sams, Clarence

2002-01-01

Desert varnish is the orange to dark brown rind that accumulates on exposed rock surfaces in many arid environments. Samples from the Sonoran Desert of Arizona are composed predominantly of clays (illite, smectite) and Mn- and Fe- oxides (birnessite, hematite). Features that appear to be single organisms are found within the varnish and at the rock-varnish interface. Many of these features are embedded in films that strongly resemble the water-rich extracellular polysaccharides produced by diverse microorganisms. Most common are rod-shaped celllike objects, 0.5-2 microns in the longest dimension, located within the varnish coatings. Some of these objects are shown to contain amines by fluorescence microscopy. The rod-shaped objects are observed in various states of degradation, as indicated by C and S abundances. Rods with higher C and S abundances appear less degraded than those with lower concentrations of these two elements. Regions rich in apparent microbes are present, while other regions display Mn- and Fe-rich mineral fabrics with microbe-sized voids and no obvious cells. These textures are interpreted as biofabrics, preserved by the precipitation of Mn and Fe minerals. We are researching the preservation of biofabrics by desert varnish in Earth's geological record. Rock coatings may similarly preserve evidence of microbial life on the hyper-arid surface of Mars.

Models for electromagnetic scattering from the sea at extremely low grazing angles

NASA Astrophysics Data System (ADS)

Wetzel, Lewis B.

1987-12-01

The present state of understanding in the field of low-grazing-angle sea scatter is reviewed and extended. The important concept of shadowing is approached from the point of view of diffraction theory, and limits in wind speed and radar frequency are found for the application of shadowing theories based on geometrical optics. The implications of shadowing function based on illumination thresholding are shown to compare favorably with a variety of experimental results. Scattering from the exposed surface peaks is treated by a composite-surface Bragg model, and by wedge models using both physical optics and the method of equivalent currents. Curiously, the scattering levels predicted by these widely different approximations are all in fairly good agreement with experimental values for moderately low grazing angles (about 5 deg), with the physical optics wedge model being superior at 1 deg. A new scattering feature, the slosh, is introduced, with scattering behavior that resembles the temporal and polarization dependence of observed low angle returns from calm water. The plume model of scattering from breaking waves (from earlier work) is discussed as a source of high-intensity Sea Spikes. It is emphasized that the prediction of low angle scattering from the sea will require considerably more information about the shape, size, and distribution of the actual scattering features.

Modeling the reflectance spectrum of Callisto 0.25 to 4.1μm

USGS Publications Warehouse

Calvin, Wendy M.; Clark, Roger N.

1991-01-01

The reflectance spectrum of Callisto from 0.2 to 4.1 μm is modeled using a simultaneous intimate plus areal mixture solution of ice and dark material which satisfies absorption band depths and reflectance levels. The model uses the radiative transfer theory based on Hapke's (1981, J. Geophys. Res. 86, 3039–3054) work, optical constants of materials and includes effects of grain size and abundance of each material. The best-fitting models contain 20–45 wt% ice in the optical surface. The models indicate that the ice component of the surface is fairly large gained and that the ice cannot account for major spectral features beyond approximately 2.5 μm. In this spectral region other hydrated minerals must dominate. A variety of reasonably well-fitting models were found and the amount of ice determined for these best fits was mathematically removed from the original Callisto spectrum. All of the spectra determined for the non-material were quite similar to each other and have absorption features that resemble hydrated silicates bearing both oxidation states of iron. Certain features in the Callisto non-ice spectrum can be duplicated by mixtures of Fe- and Mg-end member serpentines. Discrepancies indicate that other phases, possibly opaque minerals, are also required to match the entire spectrum. The unusual Fe-serpentines are commonly found in the matrices of primitive cabodnaceous chondrites, suggesting that other matrix phases may also be likely candidates for the Callisto non-ice material.

Functional-adaptive analysis of the hindlimb anatomy of extant marsupials and the paleobiology of the Paleocene marsupials Mayulestes ferox and Pucadelphys andinus.

PubMed

Argot, Christine

2002-07-01

This article analyzes the adaptations of the hindlimb of two Early Paleocene marsupials, Mayulestes ferox and Pucadelphys andinus. This analysis is based on detailed comparisons with various extant marsupials, both South American and Australian. In the case of the South American opossums, original myological data were collected and osteological-myological associations were related to their locomotor behavior. The use of Australian genera helped to improve the appraisal of the locomotory habits of the fossil taxa. Several features are indicative of the ability of Mayulestes to climb or walk on uneven surfaces (e.g., very mobile hip joint, astragalocalcaneal joint pattern), and some other features emphasize a relative agility (e.g., strongly everted iliac blades, morphology of the distal epiphysis of the femur, medially stabilized cruroastragalar joint). Pucadelphys exhibits a hindlimb relatively similar morphologically to that of Mayulestes, but with features indicating slightly increased agility and a terrestrial component that is more emphasized than in Mayulestes. The Tiupampa fossils were therefore more agile than most living didelphids and resembled the condition observed in living dasyurids more. These conclusions complement a previous study performed on the forelimb of these fossils. Copyright 2002 Wiley-Liss, Inc.

Periodic protein adsorption at the gold/biotin aqueous solution interface: evidence of kinetics with time delay

NASA Astrophysics Data System (ADS)

Neff, H.; Laborde, H. M.; Lima, A. M. N.

2016-11-01

An oscillatory molecular adsorption pattern of the protein neutravidin from aqueous solution onto gold, in presence of a pre-deposited self assembled mono-molecular biotin film, is reported. Real time surface Plasmon resonance sensing was utilized for evaluation of the adsorption kinetics. Two different fractions were identified: in the initial phase, protein molecules attach irreversibly onto the Biotin ligands beneath towards the jamming limit, forming a neutravidin-biotin fraction. Afterwards, the growth rate exhibits distinct, albeit damped adsorption-desorption oscillations over an extended time span, assigned to a quasi reversibly bound fraction. These findings agree with, and firstly confirm a previously published model, proposing macro-molecular adsorption with time delay. The non-linear dynamic model is applicable to and also resembles non-damped oscillatory binding features of the hetero-catalytic oxidation of carbon monoxide molecules on platinum in the gas phase. An associated surface residence time can be linked to the dynamics and time scale required for self-organization.

Biomimicry of multifunctional nanostructures in the neck feathers of mallard (Anas platyrhynchos L.) drakes

NASA Astrophysics Data System (ADS)

Khudiyev, Tural; Dogan, Tamer; Bayindir, Mehmet

2014-04-01

Biological systems serve as fundamental sources of inspiration for the development of artificially colored devices, and their investigation provides a great number of photonic design opportunities. While several successful biomimetic designs have been detailed in the literature, conventional fabrication techniques nonetheless remain inferior to their natural counterparts in complexity, ease of production and material economy. Here, we investigate the iridescent neck feathers of Anas platyrhynchos drakes, show that they feature an unusual arrangement of two-dimensional (2D) photonic crystals and further exhibit a superhydrophobic surface, and mimic this multifunctional structure using a nanostructure composite fabricated by a recently developed top-down iterative size reduction method, which avoids the above-mentioned fabrication challenges, provides macroscale control and enhances hydrophobicity through the surface structure. Our 2D solid core photonic crystal fibres strongly resemble drake neck plumage in structure and fully polymeric material composition, and can be produced in wide array of colors by minor alterations during the size reduction process.

Biomimicry of multifunctional nanostructures in the neck feathers of mallard (Anas platyrhynchos L.) drakes

PubMed Central

Khudiyev, Tural; Dogan, Tamer; Bayindir, Mehmet

2014-01-01

Biological systems serve as fundamental sources of inspiration for the development of artificially colored devices, and their investigation provides a great number of photonic design opportunities. While several successful biomimetic designs have been detailed in the literature, conventional fabrication techniques nonetheless remain inferior to their natural counterparts in complexity, ease of production and material economy. Here, we investigate the iridescent neck feathers of Anas platyrhynchos drakes, show that they feature an unusual arrangement of two-dimensional (2D) photonic crystals and further exhibit a superhydrophobic surface, and mimic this multifunctional structure using a nanostructure composite fabricated by a recently developed top-down iterative size reduction method, which avoids the above-mentioned fabrication challenges, provides macroscale control and enhances hydrophobicity through the surface structure. Our 2D solid core photonic crystal fibres strongly resemble drake neck plumage in structure and fully polymeric material composition, and can be produced in wide array of colors by minor alterations during the size reduction process. PMID:24751587

Biomimicry of multifunctional nanostructures in the neck feathers of mallard (Anas platyrhynchos L.) drakes.

PubMed

Khudiyev, Tural; Dogan, Tamer; Bayindir, Mehmet

2014-04-22

Biological systems serve as fundamental sources of inspiration for the development of artificially colored devices, and their investigation provides a great number of photonic design opportunities. While several successful biomimetic designs have been detailed in the literature, conventional fabrication techniques nonetheless remain inferior to their natural counterparts in complexity, ease of production and material economy. Here, we investigate the iridescent neck feathers of Anas platyrhynchos drakes, show that they feature an unusual arrangement of two-dimensional (2D) photonic crystals and further exhibit a superhydrophobic surface, and mimic this multifunctional structure using a nanostructure composite fabricated by a recently developed top-down iterative size reduction method, which avoids the above-mentioned fabrication challenges, provides macroscale control and enhances hydrophobicity through the surface structure. Our 2D solid core photonic crystal fibres strongly resemble drake neck plumage in structure and fully polymeric material composition, and can be produced in wide array of colors by minor alterations during the size reduction process.

The metaplastic variant of Warthin tumor of the parotid gland: dynamic multislice computerized tomography and magnetic resonance imaging findings with histopathologic correlation in a case.

PubMed

Yerli, Hasan; Avci, Suat; Aydin, Erdinc; Arikan, Unser

2010-03-01

Metaplastic Warthin tumor is a rarely seen subtype of Warthin tumor. It can resemble squamous carcinomas histopathologically, because it contains atypical squamous cells on the necrotic surface. Making a diagnosis can become easier by knowing this entity of Warthin tumor well and by correlating the radiologic findings with pathology. In this case presentation, imaging features of a metaplastic Warthin tumor are presented together with its histopathologic findings. When a solid mass with peripheral enhancing cystic-necrotic component and well defined contour and capsule that shows early enhancement and washout is identified with imaging methods in parotid gland, metaplastic Warthin tumor should be indicated in the differential diagnosis before the histopathologic evaluation. Copyright 2010 Mosby, Inc. All rights reserved.

Europa Broken Ice

NASA Image and Video Library

1997-09-07

Jupiter moon Europa, as seen in this image taken June 27, 1996 by NASA Galileo spacecraft, displays features in some areas resembling ice floes seen in Earth polar seas. http://photojournal.jpl.nasa.gov/catalog/PIA00291

Structure of Glycerol Dehydratase Reactivase: A New Type of Molecular Chaperone

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

Liao, Der-Ing; Reiss, Lisa; Turner, Jr., Ivan

2010-03-08

The function of glycerol dehydratase (GDH) reactivase is to remove damaged coenzyme B{sub 12} from GDH that has suffered mechanism-based inactivation. The structure of GDH reactivase from Klebsiella pneumoniae was determined at 2.4 {angstrom} resolution by the single isomorphous replacement with anomalous signal (SIR/AS) method. Each tetramer contains two elongated 63 kDa {alpha} subunits and two globular 14 kDa {beta} subunits. The {alpha} subunit contains structural features resembling both GroEL and Hsp70 groups of chaperones, and it appears chaperone like in its interactions with ATP. The fold of the {beta} subunit resembles that of the {beta} subunit of glycerol dehydratase,more » except that it lacks some coenzyme B12 binding elements. A hypothesis for the reactivation mechanism of reactivase is proposed based on these structural features.« less

Dedifferentiated liposarcoma with inflammatory myofibroblastic tumor-like features.

PubMed

Lucas, David R; Shukla, Abhishek; Thomas, Dafydd G; Patel, Rajiv M; Kubat, Anthony J; McHugh, Jonathan B

2010-06-01

The dedifferentiated component of dedifferentiated liposarcoma shows wide histologic variation including tumors with heterologous differentiation. Myofibroblastic differentiation has been recognized in dedifferentiated liposarcoma. However, tumors closely resembling inflammatory myofibroblastic tumor have not. We report the clinicopathologic, immunohistochemical, and molecular finding in 6 cases of dedifferentiated liposarcoma with inflammatory myofibroblastic tumor-like features treated at our institution. The tumors occurred mostly in middle age or elderly men, involved mostly the inguinal/scrotal region or retroperitoneum, and behaved aggressively. Microscopically, the dedifferentiated component closely resembled or, if taken out of context, was indistinguishable from inflammatory myofibroblastic tumor. All 3 major patterns seen in inflammatory myofibroblastic tumor (myxoid, cellular, and hypocellular fibrous) were represented. Areas resembling nodular fasciitis or desmoid fibromatosis were frequent findings. One tumor had heterologous osseous differentiation. In 4 tumors the inflammatory myofibroblastic tumor-like areas were diffuse, whereas in 2 they were combined with noninflammatory myofibroblastic tumor-like high-grade sarcoma. Five tumors stained for smooth muscle actin or desmin, none stained for ALK-1, 5 stained for MDM2, and 5 had amplified MDM2 by fluorescence in situ hybridization. Well-differentiated liposarcomatous components were present in every tumor. All patients developed locally recurrent or metastatic disease. At last follow-up 2 patients had died of disease and 2 were alive with disease. Dedifferentiated liposarcoma can have prominent inflammatory myofibroblastic tumor-like features, a finding that further expands its histologic spectrum. Awareness of this finding can prevent one from misdiagnosing dedifferentiated liposarcoma as inflammatory myofibroblastic tumor, a much less aggressive neoplasm.

Sternaspidae (Annelida, Sedentaria) from Vietnam with description of three new species and clarification of some morphological features.

PubMed

Zhadan, Anna E; Tzetlin, Alexander B; Salazar-Vallejo, Sergio I

2017-01-25

Five sternaspid species were found near Vietnam shores: Sternaspis britayevi sp. nov., S. costata von Marenzeller, 1879, S. nana sp. nov., S. papillosa sp. nov., and S. spinosa Sluiter 1882. Sternaspis britayevi is described from the shallow water in Vietnam inhabiting soft bottoms; it resembles S. spinosa described from Java and S. thorsoni Sendall & Salazar-Vallejo, 2013 described from the Persian Gulf, but differs in having a medially projected and markedly ribbed fan of the ventro-caudal shield and nearly parallel, distally widened and rounded branchial plates. Sternaspis nana sp. nov. is described from Nha Trang Bay; it differs from the other known species by the combination of the following characters: small size, evenly distributed micropapillae and regular rows of long cirriform papillae; posterior chaetal fascicles consisting of single thick chaeta; a ventral shield with smooth integument, without ribs and usually without concentric lines. Sternaspis papillosa sp. nov. is also described from Nha Trang Bay; it resembles S. africana Augener, 1918 and S. andamanensis Sendall & Salazar-Vallejo, 2013 by having similar ventro-caudal shields but differs by body papillation and details of the ventro-caudal shield. Based upon observations of different species some morphological features are clarified: 1) notochaetae are present in introvert chaetigers as delicate capillaries; 2) peg-chaetae are really a dense group of more than 100 thin individual chaetae, embedded in a fibrous matrix, and covered by a common sheath; 3) the pharynx is an eversible, lobed, axial non-muscular proboscis with a ciliated surface; 4) the body cavity is divided by three septa in the anterior body region, and there are no other septa; and 5) an eversible anal peduncle is confirmed, as has been shown by early taxonomists.

Photometric properties of Titan's surface from Cassini VIMS: Relevance to titan's hemispherical albedo dichotomy and surface stability

USGS Publications Warehouse

Nelson, R.M.; Brown, R.H.; Hapke, B.W.; Smythe, W.D.; Kamp, L.; Boryta, M.D.; Leader, F.; Baines, K.H.; Bellucci, G.; Bibring, J.-P.; Buratti, B.J.; Capaccioni, F.; Cerroni, P.; Clark, R.N.; Combes, M.; Coradini, A.; Cruikshank, D.P.; Drossart, P.; Formisano, V.; Jaumann, R.; Langevin, Y.; Matson, D.L.; McCord, T.B.; Mennella, V.; Nicholson, P.D.; Sicardy, B.; Sotin, Christophe

2006-01-01

The Visual and Infrared Mapping Spectrometer (VIMS) instrument on the Cassini Saturn Orbiter returned spectral imaging data as the spacecraft undertook six close encounters with Titan beginning 7 July, 2004. Three of these flybys each produced overlapping coverage of two distinct regions of Titan's surface. Twenty-four points were selected on approximately opposite hemispheres to serve as photometric controls. Six points were selected in each of four reflectance classes. On one hemisphere each control point was observed at three distinct phase angles. From the derived phase coefficients, preliminary normal reflectances were derived for each reflectance class. The normal reflectance of Titan's surface units at 2.0178 ??m ranged from 0.079 to 0.185 for the most absorbing to the most reflective units assuming no contribution from absorbing haze. When a modest haze contribution of ??=0.1 is considered these numbers increase to 0.089-0.215. We find that the lowest three reflectance classes have comparable normal reflectance on either hemisphere. However, for the highest brightness class the normal reflectance is higher on the hemisphere encompassing longitude 14-65?? compared to the same high brightness class for the hemisphere encompassing 122-156?? longitude. We conclude that an albedo dichotomy observed in continental sized units on Titan is due not only to one unit having more areal coverage of reflective material than the other but the material on the brighter unit is intrinsically more reflective than the most reflective material on the other unit. This suggests that surface renewal processes are more widespread on Titan's more reflective units than on its less reflective units. We note that one of our photometric control points has increased in reflectance by 12% relative to the surrounding terrain from July of 2004 to April and May of 2005. Possible causes of this effect include atmospheric processes such as ground fog or orographic clouds; the suggestion of active volcanism cannot be ruled out. Several interesting circular features which resembled impact craters were identified on Titan's surface at the time of the initial Titan flyby in July of 2004. We traced photometric profiles through two of these candidate craters and attempted to fit these profiles to the photometric properties expected from model depressions. We find that the best-fit attempt to model these features as craters requires that they be unrealistically deep, approximately 70 km deep. We conclude that despite their appearance, these circular features are not craters, however, the possibility that they are palimpsests cannot be ruled out. We used two methods to test for the presence of vast expanses of liquids on Titan's surface that had been suggested to resemble oceans. Specular reflection of sunlight would be indicative of widespread liquids on the surface; we found no evidence of this. A large liquid body should also show uniformity in photometric profile; we found the profiles to be highly variable. The lack of specular reflection and the high photometric variability in the profiles across candidate oceans is inconsistent with the presence of vast expanses of flat-lying liquids on Titan's surface. While liquid accumulation may be present as small, sub-pixel-sized bodies, or in areas of the surface which still remain to be observed by VIMS, the presence of large ocean-sized accumulations of liquids can be ruled out. The Cassini orbital tour offers the opportunity for VIMS to image the same parts of Titan's surface repeatedly at many different illumination and observation geometries. This creates the possibility of understanding the properties of Titan's atmosphere and haze by iteratively adapting models to create a best fit to the surface reflectance properties. ?? 2006 Elsevier Ltd. All rights reserved.

The Morphometrics of “Masculinity” in Human Faces

PubMed Central

Mitteroecker, Philipp; Windhager, Sonja; Müller, Gerd B.; Schaefer, Katrin

2015-01-01

In studies of social inference and human mate preference, a wide but inconsistent array of tools for computing facial masculinity has been devised. Several of these approaches implicitly assumed that the individual expression of sexually dimorphic shape features, which we refer to as maleness, resembles facial shape features perceived as masculine. We outline a morphometric strategy for estimating separately the face shape patterns that underlie perceived masculinity and maleness, and for computing individual scores for these shape patterns. We further show how faces with different degrees of masculinity or maleness can be constructed in a geometric morphometric framework. In an application of these methods to a set of human facial photographs, we found that shape features typically perceived as masculine are wide faces with a wide inter-orbital distance, a wide nose, thin lips, and a large and massive lower face. The individual expressions of this combination of shape features—the masculinity shape scores—were the best predictor of rated masculinity among the compared methods (r = 0.5). The shape features perceived as masculine only partly resembled the average face shape difference between males and females (sexual dimorphism). Discriminant functions and Procrustes distances to the female mean shape were poor predictors of perceived masculinity. PMID:25671667

Modelling of backscatter from vegetation layers

NASA Technical Reports Server (NTRS)

Van Zyl, J. J.; Engheta, N.; Papas, C. H.; Elachi, C.; Zebker, H.

1985-01-01

A simple way to build up a library of models which may be used to distinguish between the different types of vegetation and ground surfaces by means of their backscatter properties is presented. The curve of constant power received by the antenna (Gamma sphere) is calculated for the given Stokes Scattering Operator, and model parameters are adopted of the most similar library model Gamma sphere. Results calculated for a single scattering model resembling coniferous trees are compared with the Gamma spheres of a model resembling tropical region trees. The polarization which would minimize the effect of either the ground surface or the vegetation layer can be calculated and used to analyze the backscatter from the ground surface/vegetation layer combination, and enhance the power received from the desired part of the combination.

Titan's "Hot Cross Bun": A Titan Laccolith?

NASA Astrophysics Data System (ADS)

Lopes, Rosaly M. C.; Stofan, E. R.; Wall, S. D.; Wood, C.; Kirk, R. L.; Lucas, A.; Mitchell, K. L.; Lunine, J. I.; Turtle, E. P.; Radebaugh, J.; Malaska, M.; Cassini RADAR Team

2012-10-01

Cassini’s RADAR instrument acquired Synthetic Aperture Radar data during the T83 flyby on May 22, 2012. The data showed a feature centered at 38.5N, 203W that resembles a “hot cross bun”. This type of feature has not been seen on Titan before, even though 52% of Titan’s surface has been imaged using SAR. The feature, approximately 100 km across, is mostly radar bright but the cross pattern, interpreted to be extensional fractures, located roughly at the center of the brighter area, appears darker at radar wavelengths (2.3 cm). Radar illumination of the image indicates that the fractures are lower in elevation than the surrounding bright region. The morphology of the region is markedly similar to that of a 30-km dome-shaped feature on Venus that lies at the summit of the Kunapipi volcano. The Venus feature is interpreted to be the result of intrusion of magma at the summit of the volcano [1]. A similar feature, interpreted as a laccolith, is seen on the Moon near the crater Ramsden [2]. The lunar feature, imaged by the Lunar Reconnaissance Orbiter, shows the cross-shaped depression over a 300 m high rise. No topographic data for the feature on Titan are available at this time, but the morphology seen by the SAR data suggests that the feature may have been formed by material pushing up from below. Laccoliths form when an igneous intrusion splits apart two strata, resulting in a domeline structure. This previously unknown type of structure on Titan may be yet another indication of cryovolcanism. [1] Stofan, E.R., et al, Icarus, 152, 75-95, 2001. [2] Wichman, R.W. and Schultz, P. H. (1996). Icarus, 122, Issue 1, July 1996, pages 193-199. doi:10.1006/icar.1996.0118

Druggable Protein Interaction Sites Are More Predisposed to Surface Pocket Formation than the Rest of the Protein Surface

PubMed Central

Johnson, David K.; Karanicolas, John

2013-01-01

Despite intense interest and considerable effort via high-throughput screening, there are few examples of small molecules that directly inhibit protein-protein interactions. This suggests that many protein interaction surfaces may not be intrinsically “druggable” by small molecules, and elevates in importance the few successful examples as model systems for improving our fundamental understanding of druggability. Here we describe an approach for exploring protein fluctuations enriched in conformations containing surface pockets suitable for small molecule binding. Starting from a set of seven unbound protein structures, we find that the presence of low-energy pocket-containing conformations is indeed a signature of druggable protein interaction sites and that analogous surface pockets are not formed elsewhere on the protein. We further find that ensembles of conformations generated with this biased approach structurally resemble known inhibitor-bound structures more closely than equivalent ensembles of unbiased conformations. Collectively these results suggest that “druggability” is a property encoded on a protein surface through its propensity to form pockets, and inspire a model in which the crude features of the predisposed pocket(s) restrict the range of complementary ligands; additional smaller conformational changes then respond to details of a particular ligand. We anticipate that the insights described here will prove useful in selecting protein targets for therapeutic intervention. PMID:23505360

Object Recognition in Mental Representations: Directions for Exploring Diagnostic Features through Visual Mental Imagery.

PubMed

Roldan, Stephanie M

2017-01-01

One of the fundamental goals of object recognition research is to understand how a cognitive representation produced from the output of filtered and transformed sensory information facilitates efficient viewer behavior. Given that mental imagery strongly resembles perceptual processes in both cortical regions and subjective visual qualities, it is reasonable to question whether mental imagery facilitates cognition in a manner similar to that of perceptual viewing: via the detection and recognition of distinguishing features. Categorizing the feature content of mental imagery holds potential as a reverse pathway by which to identify the components of a visual stimulus which are most critical for the creation and retrieval of a visual representation. This review will examine the likelihood that the information represented in visual mental imagery reflects distinctive object features thought to facilitate efficient object categorization and recognition during perceptual viewing. If it is the case that these representational features resemble their sensory counterparts in both spatial and semantic qualities, they may well be accessible through mental imagery as evaluated through current investigative techniques. In this review, methods applied to mental imagery research and their findings are reviewed and evaluated for their efficiency in accessing internal representations, and implications for identifying diagnostic features are discussed. An argument is made for the benefits of combining mental imagery assessment methods with diagnostic feature research to advance the understanding of visual perceptive processes, with suggestions for avenues of future investigation.

Object Recognition in Mental Representations: Directions for Exploring Diagnostic Features through Visual Mental Imagery

PubMed Central

Roldan, Stephanie M.

2017-01-01

One of the fundamental goals of object recognition research is to understand how a cognitive representation produced from the output of filtered and transformed sensory information facilitates efficient viewer behavior. Given that mental imagery strongly resembles perceptual processes in both cortical regions and subjective visual qualities, it is reasonable to question whether mental imagery facilitates cognition in a manner similar to that of perceptual viewing: via the detection and recognition of distinguishing features. Categorizing the feature content of mental imagery holds potential as a reverse pathway by which to identify the components of a visual stimulus which are most critical for the creation and retrieval of a visual representation. This review will examine the likelihood that the information represented in visual mental imagery reflects distinctive object features thought to facilitate efficient object categorization and recognition during perceptual viewing. If it is the case that these representational features resemble their sensory counterparts in both spatial and semantic qualities, they may well be accessible through mental imagery as evaluated through current investigative techniques. In this review, methods applied to mental imagery research and their findings are reviewed and evaluated for their efficiency in accessing internal representations, and implications for identifying diagnostic features are discussed. An argument is made for the benefits of combining mental imagery assessment methods with diagnostic feature research to advance the understanding of visual perceptive processes, with suggestions for avenues of future investigation. PMID:28588538

Dynamics of Phenanthrenequinone on Carbon Nano-Onion Surfaces Probed by Quasielastic Neutron Scattering

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

Anjos, Daniela M; Mamontov, Eugene; Brown, Gilbert M

We used quasielastic neutron scattering (QENS) to study the dynamics of phenanthrenequinone (PQ) on the surface of onion-like carbon (OLC), or so called carbon onions, as a function of surface coverage and temperature. For both the high- and low-coverage samples, we observed two diffusion processes; a faster process and nearly an order of magnitude slower process. On the high-coverage surface, the slow diffusion process is of long-range translational character, whereas the fast diffusion process is spatially localized on the length scale of ~ 4.7 . On the low-coverage surface, both diffusion processes are spatially localized; on the same length scalemore » of ~ 4.7 for the fast diffusion and a somewhat larger length scale for the slow diffusion. Arrhenius temperature dependence is observed except for the long-range diffusion on the high-coverage surface. We attribute the fast diffusion process to the generic localized in-cage dynamics of PQ molecules, and the slow diffusion process to the long-range translational dynamics of PQ molecules, which, depending on the coverage, may be either spatially restricted, or long-range. On the low-coverage surface, uniform surface coverage is not attained, and the PQ molecules experience the effect of spatial constraints on their long-range translational dynamics. Unexpectedly, the dynamics of PQ molecules on OLC as a function of temperature and surface coverage bears qualitative resemblance to the dynamics of water molecules on oxide surfaces, including practically temperature-independent residence times for the low-coverage surface. The dynamics features that we observed may be universal across different classes of surface adsorbates.« less

How to Spot Congenital Myasthenic Syndromes Resembling the Lambert-Eaton Myasthenic Syndrome? A Brief Review of Clinical, Electrophysiological, and Genetics Features.

PubMed

Lorenzoni, Paulo José; Scola, Rosana Herminia; Kay, Claudia Suemi Kamoi; Werneck, Lineu Cesar; Horvath, Rita; Lochmüller, Hanns

2018-06-01

Congenital myasthenic syndromes (CMS) are heterogeneous genetic diseases in which neuromuscular transmission is compromised. CMS resembling the Lambert-Eaton myasthenic syndrome (CMS-LEMS) are emerging as a rare group of distinct presynaptic CMS that share the same electrophysiological features. They have low compound muscular action potential amplitude that increment after brief exercise (facilitation) or high-frequency repetitive nerve stimulation. Although clinical signs similar to LEMS can be present, the main hallmark is the electrophysiological findings, which are identical to autoimmune LEMS. CMS-LEMS occurs due to deficits in acetylcholine vesicle release caused by dysfunction of different components in its pathway. To date, the genes that have been associated with CMS-LEMS are AGRN, SYT2, MUNC13-1, VAMP1, and LAMA5. Clinicians should keep in mind these newest subtypes of CMS-LEMS to achieve the correct diagnosis and therapy. We believe that CMS-LEMS must be included as an important diagnostic clue to genetic investigation in the diagnostic algorithms to CMS. We briefly review the main features of CMS-LEMS.

Source misattributions and false recognition errors: examining the role of perceptual resemblance and imagery generation processes.

PubMed

Foley, Mary Ann; Bays, Rebecca Brooke; Foy, Jeffrey; Woodfield, Mila

2015-01-01

In three experiments, we examine the extent to which participants' memory errors are affected by the perceptual features of an encoding series and imagery generation processes. Perceptual features were examined by manipulating the features associated with individual items as well as the relationships among items. An encoding instruction manipulation was included to examine the effects of explicit requests to generate images. In all three experiments, participants falsely claimed to have seen pictures of items presented as words, committing picture misattribution errors. These misattribution errors were exaggerated when the perceptual resemblance between pictures and images was relatively high (Experiment 1) and when explicit requests to generate images were omitted from encoding instructions (Experiments 1 and 2). When perceptual cues made the thematic relationships among items salient, the level and pattern of misattribution errors were also affected (Experiments 2 and 3). Results address alternative views about the nature of internal representations resulting in misattribution errors and refute the idea that these errors reflect only participants' general impressions or beliefs about what was seen.

Rosette-forming glioneuronal tumor of the fourth ventricle.

PubMed

Preusser, Matthias; Dietrich, Wolfgang; Czech, Thomas; Prayer, Daniela; Budka, Herbert; Hainfellner, Johannes A

2003-11-01

Rosette-forming glioneuronal tumor (RGNT) of the fourth ventricle has been reported recently as a novel type of primary CNS neoplasm. We present the case of a 35-year-old male patient with RGNT of the fourth ventricle. The tumor was found incidentally; the patient did not suffer from any neurological symptoms. The tumor mass involved the caudal cerebellar vermis, filled the fourth ventricle and protruded into the caudal part of the mesencephalic aquaeduct. Smaller tumor nodules were visible in the adjacent right cerebellar hemisphere. Histologically, prominent neurocytic rosettes with synaptophysin expression were embedded in a glial tumor component resembling pilocytic astrocytoma. Clinicopathological features of our case closely resemble those reported in the original description. Thus, our case confirms RGNT as a new distinct type of primary CNS neoplasm. Due to its distinct features, adoption of RGNT as a new entity into the WHO classification of tumors should be considered.

Metastatic ovarian papillary cystadenocarcinoma to the small intestine serous surface: report of a case of high-grade histopathologic malignancy

PubMed Central

2014-01-01

Ovarian cystadenocarcinoma is characterized by marked heterogeneity and may be composed of an admixture of histologic growth patterns, including acinar, papillary and solid. In the present study, a case of isolated small intestine metastasis of ovarian papillary cystadenocarcinoma was reported. A 7-year-old female mixed-breed dog presented with a mass in the left upper quadrant with progressive enlargement of the abdomen, periodic bloody discharge from the vulva and incontinence. The tumor was histologically characterized by the presence of cysts and proliferation of papillae, both lined by single- or multi-layered pleomorphic epithelial cells. Furthermore, the mass was composed by intense cellular and nuclear pleomorphism and numerous mitotic figures. These findings indicate a tumor of high-grade malignancy with infiterative tumor cells resembling the papillary ovarian tumor in the serosal surface of the small intestine along with an intact serosa. Immunohistochemically, tumor was positive for CK7 and negative immunoreactivity for CK20. The histopathologic features coupled with the CK7 immunoreactivity led to a diagnosis of high grade ovarian papillary cystadenocarcinoma. To the best of our knowledge, this is the first case of small intestine serousal surface metastasis from ovarian papillary cystadenocarcinoma. PMID:24636424

Bimodality and regime behavior in atmosphere-ocean interactions during the recent climate change

NASA Astrophysics Data System (ADS)

Fallah, Bijan; Sodoudi, Sahar

2015-06-01

Maximum covariance analysis (MCA) and isometric feature mapping (Isomap) are applied to investigate the spatio-temporal atmosphere-ocean interactions otherwise hidden in observational data for the period of 1979-2010. Despite an established long-term surface warming trend for the whole northern hemisphere, sea surface temperatures (SST) in the East Pacific have remained relatively constant for the period of 2001-2010. Our analysis reveals that SST anomaly probability density function of the leading two Isomap components is bimodal. We conclude that Isomap shows the existence of two distinct regimes in surface ocean temperature, resembling the break and active phases of rainfall over equatorial land areas. These regimes occurred within two separated time windows during the past three decades. Strengthening of trade winds over Pacific was coincident with the cold phase of east equatorial Pacific. This pattern was reversed during the warm phase of east equatorial Pacific. The El Niño event of 1997/1998 happened within the transition mode between these two regimes and may be a trigger for the SST changes in the Pacific. Furthermore, we suggest that Isomap, compared with MCA, provides more information about the behavior and predictability of the inter-seasonal atmosphere-ocean interactions.

Episodic plate separation and fracture infill on the surface of Europa. Galileo Imaging Team.

PubMed

Sullivan, R; Greeley, R; Homan, K; Klemaszewski, J; Belton, M J; Carr, M H; Chapman, C R; Tufts, R; Head, J W; Pappalardo, R; Moore, J; Thomas, P

1998-01-22

Images obtained by the Voyager spacecraft revealed dark, wedge-shaped bands on Europa that were interpreted as evidence that surface plates, 50-100 km across, moved and rotated relative to each other. This implied that they may be mechanically decoupled from the interior by a layer of warm ice or liquid water. Here we report similar features seen in higher resolution images (420 metres per pixel) obtained by the Galileo spacecraft that reveal new details of wedge-band formation. In particular, the interior of one dark band shows bilateral symmetry of parallel lineaments and pit complexes which indicates that plate separation occurred in discrete episodes from a central axis. The images also show that this style of tectonic activity involved plates < 10 km across. Although this tectonic style superficially resembles aspects of similar activity on Earth, such as sea-floor spreading and the formation of ice leads in polar seas, there are significant differences in the underlying physical mechanisms: the wedge-shaped bands on Europa most probably formed when lower material (ice or water) rose to fill the fractures that widened in response to regional surface stresses.

Europa's Broken Ice

NASA Technical Reports Server (NTRS)

1996-01-01

Jupiter's moon Europa, as seen in this image taken June 27, 1996 by NASA's Galileo spacecraft, displays features in some areas resembling ice floes seen in Earth's polar seas. Europa, about the size of Earth's moon, has an icy crust that has been severely fractured, as indicated by the dark linear, curved, and wedged-shaped bands seen here. These fractures have broken the crust into plates as large as 30 kilometers (18.5 miles) across. Areas between the plates are filled with material that was probably icy slush contaminated with rocky debris. Some individual plates were separated and rotated into new positions. Europa's density indicates that it has a shell of water ice as thick as 100 kilometers (about 60 miles), parts of which could be liquid. Currently, water ice could extend from the surface down to the rocky interior, but the features seen in this image suggest that motion of the disrupted icy plates was lubricated by soft ice or liquid water below the surface at the time of disruption. This image covers part of the equatorial zone of Europa and was taken from a distance of 156,000 kilometers (about 96,300 miles) by the solid-state imager camera on the Galileo spacecraft. North is to the right and the sun is nearly directly overhead. The area shown is about 360 by 770 kilometers (220-by-475 miles or about the size of Nebraska), and the smallest visible feature is about 1.6 kilometers (1 mile) across. The Jet Propulsion Laboratory manages the Galileo mission for NASA's Office of Space Science.

Adsorption energy as a metric for wettability at the nanoscale

PubMed Central

Giro, Ronaldo; Bryant, Peter W.; Engel, Michael; Neumann, Rodrigo F.; Steiner, Mathias B.

2017-01-01

Wettability is the affinity of a liquid for a solid surface. For energetic reasons, macroscopic drops of liquid form nearly spherical caps. The degree of wettability is then captured by the contact angle where the liquid-vapor interface meets the solid-liquid interface. As droplet volumes shrink to the scale of attoliters, however, surface interactions become significant, and droplets assume distorted shapes. In this regime, the contact angle becomes ambiguous, and a scalable metric for quantifying wettability is needed, especially given the emergence of technologies exploiting liquid-solid interactions at the nanoscale. Here we combine nanoscale experiments with molecular-level simulation to study the breakdown of spherical droplet shapes at small length scales. We demonstrate how measured droplet topographies increasingly reveal non-spherical features as volumes shrink. Ultimately, the nanoscale droplets flatten out to form layer-like molecular assemblies at the solid surface. For the lack of an identifiable contact angle at small scales, we introduce a droplet’s adsorption energy density as a new metric for a liquid’s affinity for a surface. We discover that extrapolating the macroscopic idealization of a drop to the nanoscale, though it does not geometrically resemble a realistic droplet, can nonetheless recover its adsorption energy if line tension is included. PMID:28397869

Phenotypic features of the domestic pigs bred in the Roman settlements of Pompeii and Caralis.

PubMed

Manca, Paolo; Farina, Vittorio; Gadau, Sergio; Lepore, Gianluca; Genovese, Angelo; Zedda, Marco

2004-01-01

A reconstruction of the morphological features of domestic pigs from two Roman settlements is here suggested by means of the study of skeletal and dental remains, with the aim at evaluating their degree of selection in comparison with wild boars. Material was formed by 111 bone and tooth fragments and was uncovered during the excavations of Polybius' House in Pompeii and of Roman buildings in the neighbourhood of Caralis harbour (Sardinia). The remains underwent morphological examination. The eruption of permanent teeth and ossification of epiphyseal cartilages let us establish that most animals were over 18-20 months. When possible, the determination of sex was made by detecting tusk features. The presence of anthropic signs on the bone surface provides some information about slaughtering and cooking procedure in the Roman period and supports the hypothesis that the animal remnants were food remains. Osteometric analysis was carried out on long and short bones and teeth through suitable multiplicative parameters, leading to the assessment of the withers height and other main phenotypic features. Logarithmic deviation pointed out the significant osteometric differences between the domestic pigs from the two Roman settlements. These data were also compared with those from wild boars and modern crossbred wild boars X non-selected pigs. In conclusion, our data show that pigs from Caralis bear much resemblance to wild boars, whereas those from Pompeii appear to be improved, so sharing some phenotypic features of modem improved breeds.

Conformational transition free energy profiles of an adsorbed, lattice model protein by multicanonical Monte Carlo simulation

NASA Astrophysics Data System (ADS)

Castells, Victoria; Van Tassel, Paul R.

2005-02-01

Proteins often undergo changes in internal conformation upon interacting with a surface. We investigate the thermodynamics of surface induced conformational change in a lattice model protein using a multicanonical Monte Carlo method. The protein is a linear heteropolymer of 27 segments (of types A and B) confined to a cubic lattice. The segmental order and nearest neighbor contact energies are chosen to yield, in the absence of an adsorbing surface, a unique 3×3×3 folded structure. The surface is a plane of sites interacting either equally with A and B segments (equal affinity surface) or more strongly with the A segments (A affinity surface). We use a multicanonical Monte Carlo algorithm, with configuration bias and jump walking moves, featuring an iteratively updated sampling function that converges to the reciprocal of the density of states 1/Ω(E), E being the potential energy. We find inflection points in the configurational entropy, S(E)=klnΩ(E), for all but a strongly adsorbing equal affinity surface, indicating the presence of free energy barriers to transition. When protein-surface interactions are weak, the free energy profiles F(E)=E-TS(E) qualitatively resemble those of a protein in the absence of a surface: a free energy barrier separates a folded, lowest energy state from globular, higher energy states. The surface acts in this case to stabilize the globular states relative to the folded state. When the protein surface interactions are stronger, the situation differs markedly: the folded state no longer occurs at the lowest energy and free energy barriers may be absent altogether.

Microbial mat records in siliciclastic rocks: Examples from Four Indian Proterozoic basins and their modern equivalents in Gulf of Cambay

NASA Astrophysics Data System (ADS)

Sarkar, Subir; Banerjee, Santanu; Samanta, Pradip; Chakraborty, Nivedita; Chakraborty, Partha Pratim; Mukhopadhyay, Soumik; Singh, Arvind K.

2014-09-01

Microbial mat-related structures (MRS) in siliciclastics have been investigated from four Proterozic formations in India, namely the Marwar Supergroup, the Vindhyan Supergroup, the Chhatisgarh Supergroup and the Khariar Group for their spectral variations, genetic aspects, palaeo-environmental significance and influence on sequence stratigraphic architecture. The maximum diversification of MRS has been experienced in shallow marine coastal Precambrian successions. Observations made from modern environment as well as Precambrian rock records clearly indicates that the features like petee ridges, sand-cracks, gas domes, multi-directed ripples, reticulate surfaces, sieve-like surfaces and setulf are most likely to form in the shallowest part of the marine basins, in upper intertidal to supratidal conditions while wrinkle structures, roll-up structures and patchy ripples had a broader range of palaeogeographic settings from the supratidal to subtidal conditions. Discoidal microbial colony (DMC) represents a special variety of the mat-layer feature in modern environment that may have diverse internal architecture, sometimes falsely resembles Ediacaran medusoids. The uniqueness in sequence stratigraphic architecture of the microbial mat-covered sediment is reflected by the presence of more amalgamated HSTs compare to that of TSTs. The preservation of forced and normal regressive deposits on low-gradient epeiric shelf under low continental freeboard indicates microbial mat-infested sea-floor impedes erosion and concomitant sediment supply may facilitate formation and preservation of regressive packages.

The formation of sharp edges in planetary rings by nearby satellites

NASA Astrophysics Data System (ADS)

Borderies, N.; Goldreich, P.; Tremaine, S.

1989-08-01

Equations are derived which govern the shapes of the perturbed streamlines near the 'sharp edge' boundaries between regions of high and low planetary ring optical depth; these are maintained by the shepherd satellites, which transfer angular momentum to and from ring particles. The results obtained by these equations' solution with a simple numerical model, whose parameters resemble those of the Encke division, are found to faithfully reproduce the sharp edges bounding the division; they imply that the ring thickness in the unperturbed regions far from the edges is of the order of 10 m, and that the angle-averaged surface density varies on a much shorter radial length scale than that over which the satellite torque is applied. This feature's relationship to the local reversal of angular momentum viscous transport, in the most strongly perturbed regions, is demonstrated.

The geologic development of Mars - A review

NASA Technical Reports Server (NTRS)

Mutch, T. A.; Saunders, R. S.

1976-01-01

The overall view of Mars has changed from earthlike in the prespacecraft era to moonlike following the flyby missions and finally to a planet with intermediate characteristics. There are many impact craters as on the moon, but tectonic and volcanic features resembling structures on earth are also present. However, there is a lack of evidence for the compressional deformation associated with terrestrial plate tectonics and continental drift. Current analyses indicate that Mars has a differentiated interior with a crust and mantle and perhaps a core. Whenever the nature of interior processes, whether overall mantle expansion, plumes, or full-scale convection, the effects at the surface have been predominantly vertical with formation of broad regions of uplift and depression. One of the results is hemispheric asymmetry with cratered terrain in the south and younger uncratered plains in the north.

'Rubber Duck' on Ceres

NASA Image and Video Library

2017-10-12

This image from NASA's Dawn spacecraft shows a group of craters, left of center, that resembles a rubber duck. Halki Crater, the "head," is 12 miles (20 kilometers) in diameter, while Telepinu Crater, the "body," is 19 miles (31 kilometers) across. They can be found in the global map of Ceres' names. The "beak" crater is unnamed. Halki and Telepinu have both been recently added to the list of official names for Ceres' geological features. They are both named after Hittite (Asia Minor) deities: the goddess of grain and the god of fertility and vegetation, respectively. Dawn acquired this picture on August 20, 2015, from its high-altitude mapping orbit at about 915 miles (1,470 kilometers) above the surface. The center coordinates of this image are 26 degrees north latitude, 339 degrees east longitude. https://photojournal.jpl.nasa.gov/catalog/PIA21909

The formation of sharp edges in planetary rings by nearby satellites

NASA Technical Reports Server (NTRS)

Borderies, Nicole; Goldreich, Peter; Tremaine, Scott

1989-01-01

Equations are derived which govern the shapes of the perturbed streamlines near the 'sharp edge' boundaries between regions of high and low planetary ring optical depth; these are maintained by the shepherd satellites, which transfer angular momentum to and from ring particles. The results obtained by these equations' solution with a simple numerical model, whose parameters resemble those of the Encke division, are found to faithfully reproduce the sharp edges bounding the division; they imply that the ring thickness in the unperturbed regions far from the edges is of the order of 10 m, and that the angle-averaged surface density varies on a much shorter radial length scale than that over which the satellite torque is applied. This feature's relationship to the local reversal of angular momentum viscous transport, in the most strongly perturbed regions, is demonstrated.

Characterization of ethylcellulose and hydroxypropyl methylcellulose thin films deposited by matrix-assisted pulsed laser evaporation

NASA Astrophysics Data System (ADS)

Palla-Papavlu, A.; Rusen, L.; Dinca, V.; Filipescu, M.; Lippert, T.; Dinescu, M.

2014-05-01

In this study is reported the deposition of hydroxypropyl methylcellulose (HPMC) and ethylcellulose (EC) by matrix-assisted pulsed laser evaporation (MAPLE). Both HPMC and EC were deposited on silicon substrates using a Nd:YAG laser (266 nm, 5 ns laser pulse and 10 Hz repetition rate) and then characterized by atomic force microscopy and Fourier transform infrared spectroscopy. It was found that for laser fluences up to 450 mJ/cm2 the structure of the deposited HPMC and EC polymer in the thin film resembles to the bulk. Morphological investigations reveal island features on the surface of the EC thin films, and pores onto the HPMC polymer films. The obtained results indicate that MAPLE may be an alternative technique for the fabrication of new systems with desired drug release profile.

Oceans, Ice Shells, and Life on Europa

NASA Technical Reports Server (NTRS)

Schenk, Paul

2002-01-01

The four large satellites of Jupiter are famous for their planet-like diversity and complexity, but none more so than ice-covered Europa. Since the provocative Voyager images of Europa in 1979, evidence has been mounting that a vast liquid water ocean may lurk beneath the moon's icy surface. Europa has since been the target of increasing and sometimes reckless speculation regarding the possibility that giant squid and other creatures may be swimming its purported cold, dark ocean. No wonder Europa tops everyone's list for future exploration in the outer solar system (after the very first reconnaissance of Pluto and the Kuiper belt, of course). Europa may be the smallest of the Galilean moons (so-called because they were discovered by Galileo Galilei in the early 17th century) but more than makes up for its diminutive size with a crazed, alien landscape. The surface is covered with ridges hundreds of meters high, domes tens of kilometers across, and large areas of broken and disrupted crust called chaos. Some of the geologic features seen on Europa resemble ice rafts floating in polar seas here on Earth-reinforcing the idea that an ice shell is floating over an ocean on this Moon-size satellite. However, such features do not prove that an ocean exists or ever did. Warm ice is unusually soft and will flow under its own weight. If the ice shell is thick enough, the warm bottom of the shell will flow, as do terrestrial glaciers. This could produce all the observed surface features on Europa through a variety of processes, the most important of which is convection. (Convection is the vertical overturn of a layer due to heating or density differences-think of porridge or sauce boiling on the stove.) Rising blobs from the base of the crust would then create the oval domes dotting Europa's surface. The strongest evidence for a hidden ocean beneath Europa's surface comes from the Galileo spacecraft's onboard magnetometer, which detected fluctuations in Jupiter's magnetic field consistent with a conductor inside Europa. The most likely conductor: a somewhat salty ocean.

Diary of events in a thoroughly unhaunted house.

PubMed

Houran, J; Lange, R

1996-10-01

Two subjects were asked to keep a 30-day journal of occurrences in their residence which are traditionally associated with hauntings and poltergeist-like phenomena. It was expected that the instructions would increase the frequency of perception of unusual or rarely occurring events in their residence, resulting in an attentional and "perceptual contagion effect." As expected, several features of the percipients' observations closely resembled those found in previously reported poltergeist episodes. Most importantly, the distribution of perceived occurrences closely resembled the predicted logistic curve, suggesting that hauntings involve a perceptual process where initial observations "infect" later ones.

Sarcoid-resembling granulomatous lung disease secondary to occupational magnetite iron dust exposure.

PubMed

Xiao, Lewis; Kookana, Anil; McClure, Robert; Heraganahally, Subash

2018-08-01

Non-caseating granulomatous pulmonary conditions resembling sarcoidosis secondary to industrial/occupation exposure to magnetite iron ore dusts have been rarely documented in the literature. This is a case report of a 58-year-old blast crew member involved in iron ore/magnetite mining who presented with a 12-month history of chronic dry cough. High-resolution computed tomography revealed bilateral interstitial opacities. Lung biopsy demonstrated sarcoid-like granulomatous inflammation. Oral corticosteroid treatment improved the cough. Radiological features did not resolve despite treatment and yet remained stable following no subsequent exposure to iron mining dust.

A Water Rich Mars Surface Mission Scenario

NASA Technical Reports Server (NTRS)

Hoffman, Stephen; Andrews, Alida; Joosten, Kent; Watts, Kevin

2017-01-01

The surface of Mars once had abundant water flowing on its surface, but now there is a general perception that this surface is completely dry. Several lines of research have shown that there are sources of potentially large quantities of water at many locations on the surface, including regions considered as candidates for future human missions. Traditionally, system designs for these human missions are constrained to tightly recycle water and oxygen, and current resource utilization strategies involve ascent vehicle oxidizer production only. But the assumption of relatively abundant extant water may change this. Several scenarios were constructed to evaluate water requirements for human Mars expeditions to assess the impact to system design if locally produced water is available. Specifically, we have assessed water resources needed for 1) ascent vehicle oxidizer and fuel production, 2) open-loop water and oxygen life support requirements along with more robust usage scenarios, and 3) crew radiation protection augmentation. In this assessment, production techniques and the associated chemistry to transform Martian water and atmosphere into these useful commodities are identified, but production mass and power requirements are left to future analyses. The figure below illustrates the type of water need assessment performed and that will be discussed. There have been several sources of feedstock material discussed in recent literature that could be used to produce these quantities of water. This paper will focus on Mars surface features that resemble glacier-like forms on Earth. Several lines of evidence indicate that some of these features are in fact buried ice, likely remnants from an earlier ice age on Mars. This paper examines techniques and hardware systems used in the polar regions of Earth to access this buried ice and withdraw water from it. These techniques and systems will be described to illustrate options available. A technique known as a Rodriguez Well is assessed as a likely method for extracting water from these bodies of ice. The figure below is a sample of results from this assessment that will be discussed.

Including pride and its group-based, relational, and contextual features in theories of contempt.

PubMed

Sullivan, Gavin Brent

2017-01-01

Sentiment includes emotional and enduring attitudinal features of contempt, but explaining contempt as a mixture of basic emotion system affects does not adequately address the family resemblance structure of the concept. Adding forms of individual, group-based, and widely shared arrogance and contempt is necessary to capture the complex mixed feelings of proud superiority when "looking down upon" and acting harshly towards others.

Ultrastructure of the hepatocytes in a vertebrate liver without bile ducts.

PubMed Central

Youson, J H; Sidon, E W; Peek, W D; Shivers, R R

1985-01-01

Thin sections and freeze fracture replicas were used to study the structure of the hepatocytes of the parasitic adult lamprey (Petromyzon marinus L.). Despite the absence of bile ducts and bile canaliculi, the hepatocytes have some features which resemble those of cells in the livers of other vertebrates. Hepatocytes are characterised by large gap junctions, many cytoplasmic inclusions, and large deposits of iron. The latter is present throughout the cytoplasmic matrix and within large inclusion bodies which may arise through sequestration of parts of the cytoplasm by membrane isolation. There is no evidence for the involvement of hepatocytes in glucose metabolism but their fine structure reflects the production of bile products and the processing of lipoproteins. The accumulation of bile products within cytoplasmic inclusions resembles the situation resulting from biliary atresia or other cholestatic conditions in higher organisms. There is little folding of the plasma membrane facing the perivascular space (of Dissé), perhaps indicating limited involvement of this surface in the transport of bile products. Nerve endings in close apposition to hepatocytes suggest possible nervous control or metabolic function or the presence of sensory receptors in lamprey liver. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 7 Fig. 8 Fig. 9 Fig. 10 Fig. 11 Fig. 12 Fig. 13 Fig. 14 Fig. 15 Fig. 16 PMID:2999046

Isolation of Human Colon Stem Cells Using Surface Expression of PTK7.

PubMed

Jung, Peter; Sommer, Christian; Barriga, Francisco M; Buczacki, Simon J; Hernando-Momblona, Xavier; Sevillano, Marta; Duran-Frigola, Miquel; Aloy, Patrick; Selbach, Matthias; Winton, Douglas J; Batlle, Eduard

2015-12-08

Insertion of reporter cassettes into the Lgr5 locus has enabled the characterization of mouse intestinal stem cells (ISCs). However, low cell surface abundance of LGR5 protein and lack of high-affinity anti-LGR5 antibodies represent a roadblock to efficiently isolate human colonic stem cells (hCoSCs). We set out to identify stem cell markers that would allow for purification of hCoSCs. In an unbiased approach, membrane-enriched protein fractions derived from in vitro human colonic organoids were analyzed by quantitative mass spectrometry. Protein tyrosine pseudokinase PTK7 specified a cell population within human colonic organoids characterized by highest self-renewal and re-seeding capacity. Antibodies recognizing the extracellular domain of PTK7 allowed us to isolate and expand hCoSCs directly from patient-derived mucosa samples. Human PTK7+ cells display features of canonical Lgr5+ ISCs and include a fraction of cells that undergo differentiation toward enteroendocrine lineage that resemble crypt label retaining cells (LRCs). Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Human papillomavirus-related carcinoma with adenoid cystic-like features of the inferior turbinate: a case report.

PubMed

Hwang, Sun Jin; Ok, Sohea; Lee, Heung-Man; Lee, Eunjung; Park, Il-Ho

2015-02-01

Sinonasal malignancies are uncommon, but are of many different histologic types. Recently, Human papillomavirus (HPV)-related carcinoma with adenoid cystic features was reported as a new histologic form. Although this histologic type resembles an adenoid cystic carcinoma, it differs from adenoid cystic carcinomas with regard to its association with HPV. Here, we present a case of HPV-related carcinoma with adenoid cystic features in the nasal cavity. We also review the histological characters of the tumor. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Increasing occurrence of cold and warm extremes during the recent global warming slowdown.

PubMed

Johnson, Nathaniel C; Xie, Shang-Ping; Kosaka, Yu; Li, Xichen

2018-04-30

The recent levelling of global mean temperatures after the late 1990s, the so-called global warming hiatus or slowdown, ignited a surge of scientific interest into natural global mean surface temperature variability, observed temperature biases, and climate communication, but many questions remain about how these findings relate to variations in more societally relevant temperature extremes. Here we show that both summertime warm and wintertime cold extreme occurrences increased over land during the so-called hiatus period, and that these increases occurred for distinct reasons. The increase in cold extremes is associated with an atmospheric circulation pattern resembling the warm Arctic-cold continents pattern, whereas the increase in warm extremes is tied to a pattern of sea surface temperatures resembling the Atlantic Multidecadal Oscillation. These findings indicate that large-scale factors responsible for the most societally relevant temperature variations over continents are distinct from those of global mean surface temperature.

30 CFR 717.14 - Backfilling and grading of road cuts, mine entry area cuts, and other surface work areas.

Code of Federal Regulations, 2010 CFR

2010-07-01

...) Retain all earth, rock and other mineral nonwaste materials on the solid portion of existing or new... closely resemble the surface configuration of the land prior to mining. In no case may highwalls be left...

Possible Hydrovolcanic Landforms Observed in MOC NA Imagery: A Preliminary Survey

NASA Technical Reports Server (NTRS)

Farrand, W. H.; Gaddis, L. R.; Blundell, S.

2001-01-01

In a preliminary survey of MOC NA imagery, a number of features resembling table mountains, tuff rings, and near craters have been identified. Their locations and geologic significance will be discussed. Additional information is contained in the original extended abstract.

The utility of cadaver-based approaches for the teaching of human anatomy: A survey of British and Irish anatomy teachers.

PubMed

Balta, Joy Y; Cronin, Michael; Cryan, John F; O'Mahony, Siobhain M

2017-03-01

Utilizing reality anatomy such as dissection and demonstrating using cadavers has been described as a superior way to create meaning. The chemicals used to embalm cadavers differentially alter the tissue of the human body, which has led to the usage of different processes along the hard to soft-fixed spectrum of preserved cadavers. A questionnaire based approach was used to gain a better insight into the opinion of anatomists on the use of preserved cadavers for the teaching of human anatomy. This study focused on anatomy teachers in the United Kingdom and Ireland. From the 125 participating anatomists, 34.4% were medically qualified, 30.4% had a PhD in a non-anatomical science and 22.4% had a PhD in an anatomical science, these figures include ten anatomists who had combinations of MD with the two other PhD qualifications. The main findings from the questionnaire were that 61.6% of participants agreed that hard-fixed formalin cadavers accurately resemble features of a human body whereas 21.6% disagreed. Moreover, anatomists rated the teaching aids on how accurately they resemble features of the human body as follows: plastic models the least accurate followed by plastinated specimens, hard fixed cadavers; soft preserved cadavers were considered to be the most accurate when it comes to resembling features of the human body. Though anatomists considered soft preserved cadavers as the most accurate tool, further research is required in order to investigate which techniques or methods provide better teaching tool for a range of anatomical teaching levels and for surgical training. Anat Sci Educ 10: 137-143. © 2016 American Association of Anatomists. © 2016 American Association of Anatomists.

Systemic lupus erythematosus-associated neutrophilic dermatosis--an underrecognized neutrophilic dermatosis in patients with systemic lupus erythematosus.

PubMed

Larson, Allison R; Granter, Scott R

2014-03-01

Neutrophilic dermatoses are an uncommon manifestation of lupus. We describe the clinical and histopathologic features of 14 patients with systemic lupus erythematosus (SLE) and neutrophilic dermatoses, 2 of whom had no prior history of SLE. Thirteen patients were female, ranging in age from 27 to 62 years (mean age, 42.8 years). One patient was a 20-year-old man. Most lesions were described as erythematous papules and plaques and showed annular morphology in 6 patients and a photodistribution in 2 patients. Histopathologic examination in all cases showed an interstitial neutrophilic infiltrate with leukocytoclasis that ranged from sparse in 5 cases and moderate to dense in 9 cases. With one exception, those cases with moderate to dense infiltrates resembled Sweet's syndrome at scanning magnification. Two cases resembled bullous SLE, and 1 case showed overlapping features of bullous SLE and Sweet's syndrome. Interface changes were seen in 8 patients, which were subtle and vacuolar in 7. One case was associated with a florid interface tissue reaction. Dermal mucin was seen in 4 cases and was a prominent feature in only one of these. One case showed a minute discrete focus resembling palisaded neutrophilic and granulomatous dermatitis. It is important to consider SLE-associated neutrophilic dermatosis in the differential diagnosis of neutrophilic tissue reactions particularly because some patients will have no prior history of lupus. It is also important to be aware of the broad histologic spectrum that may be encountered in SLE-associated neutrophilic dermatosis, ranging from subtle paucicellular lesions to florid Sweet's-like lesions associated with a dense neutrophilic infiltrate. Copyright © 2014 Elsevier Inc. All rights reserved.

The production of arthritis in the guinea-pig by intra-articular reaction between lymphokines and inflammatory leucocytes.

PubMed Central

Limb, G. A.; Brown, K. A.; Wolstencroft, R. A.; Ellis, B. A.; Dumonde, D. C.

1989-01-01

A single intra-articular injection of lymphokine into the guinea-pig knee joint resulted in a sequence of changes in joint architecture whose histopathological features resembled that of an acute inflammatory reaction progressing to a chronic state. At 24 h there was a mild hyperplasia and hypertrophy of the synovium with intense polymorphonuclear leucocyte infiltration. At 72 h, the synovium was heavily infiltrated with diffuse and focal aggregations of mononuclear cells; erosion of cartilage and bone by synovial pannus was accompanied by a subsynovial fibrosis. By 1 week, leucocytic infiltration of the synovium had decreased markedly although the erosion and fibrosis persisted. However, when lymphokine was injected together with oil-elicited peritoneal exudate cells a more intense arthritis ensued: at 72 h synovial pannus was prominently eroding bone and this was accompanied by the appearance of multinucleate cells resembling osteoclasts in the zone of erosion. These features were shown to resemble closely the histopathology of experimental allergic arthritis in the guinea-pig, in contrast to the lesser severity of synovitis resulting from the adoptive cellular transfer of delayed hypersensitivity into the joint. The results indicate that lymphokines may play a role in the induction of experimental allergic arthritis by recruiting and activating cells involved in chronic inflammation. Images Fig. 1 Fig. 2 Fig. 3 PMID:2765396

Scaling mimesis: Morphometric and ecomorphological similarities in three sympatric plant-mimetic fish of the family Carangidae (Teleostei).

PubMed

Queiroz, Alexya Cunha de; Vallinoto, Marcelo; Sakai, Yoichi; Giarrizzo, Tommaso; Barros, Breno

2018-01-01

The mimetic juveniles of a number of carangid fish species resemble plant parts floating near the water surface, such as leaves, seeds and other plant debris. The present study is the first to verify the morphological similarities and ecomorphological relationships between three carangids (Oligoplites saurus, Oligoplites palometa and Trachinotus falcatus) and their associated plant models. Behavioral observations were conducted in the estuary of Curuçá River, in northeastern Pará (Brazil) between August 2015 and July 2016. Individual fishes and associated floating objects (models) were sampled for comparative analysis using both geometric and morphometric approaches. While the mimetic fish and their models retain their own distinct, intrinsic morphological features, a high degree of morphological similarity was found between each fish species and its model. The morphometric analyses revealed a general tendency of isometric development in all three fish species, probably related to their pelagic habitats, during all ontogenetic stages.

Dawn's Exploration of Vesta

NASA Technical Reports Server (NTRS)

Rayman, Marc D.; Mase, Robert A.

2012-01-01

On 16 July 2011, after completing nearly four years of interplanetary flight, Dawn entered orbit around (4) Vesta, the second most massive body in the main asteroid belt. Dawn used solar electric propulsion to spiral to a series of six different orbits to accomplish its science campaign. Although the transfers to progressively lower orbits presented significant challenges, all were executed smoothly. During its nearly 14 months in orbit, Dawn spiraled down to 210 km above the surface and back up, before initiating the gradual departure to travel to dwarf planet (1) Ceres for a 2015 rendezvous. Dawn's exploration of Vesta has shown it to be geologically complex and fascinating, resembling terrestrial planets more than typical asteroids. Among the principal features is a 500-km diameter impact basin within which is the second tallest mountain known in the solar system. This paper presents Dawn's operations at Vesta and summarizes the principal findings.

Water soluble cations and the fluvial history of Mars

NASA Technical Reports Server (NTRS)

Silverman, M. P.; Munoz, E. F.

1975-01-01

The electrical conductivity and water soluble Na, K, Ca, and Mg of aqueous solutions of terrestrial soils and finely divided igneous and metamorphic rocks were determined. Soils from dry terrestrial basins with a history of water accumulation as well as soils from the topographic lows of valleys accumulated water soluble cations, particularly Na and Ca. These soils as a group can be distinguished from the rocks or a second group of soils (leached upland soils and soils from sites other than the topographic lows of valleys) by significant differences in their mean electrical conductivity and water-soluble Na + Ca content. Similar measurements on multiple samples from the surface of Mars, collected by an automated long-range roving vehicle along a highlands-to-basin transect at sites with morphological features resembling dry riverlike channels, are suggested to determine the fluvial history of the planet.

Locally infiltrative ameloblastic fibroma in a rhesus macaque (Macaca mulatta) with characterizations of its proliferating activity and biological behavior

PubMed Central

Liu, David X.; Doyle, Lara A.; Bouljihad, Mostafa T.; Didier, Peter J.; Gilbert, Margaret H.; Wang, Xiaolei; Pahar, Bapi; Bohm, Rudolf P.; Veazey, Ronald S.; Lackner, Andrew A.

2014-01-01

An 8-year-old male rhesus macaque (Macaca mulatta) presented with unilateral enlargement of the left mandible. Radiographs revealed a marked expansion of the left mandible with a multilocular radiolucent mass with abundant osteolysis. The mass was grossly firm, fleshy, and gelatinous on the cut surface. Histologically, the mass was locally infiltrative and composed of neoplastic epithelial and mesenchymal components that stained positive for cytokeratin and vimentin, respectively. Occasional densely spherical condensations of fibroblasts resembling the cap stage of odontogenesis were present in the mesenchyma. Immunohistochemical staining with Ki-67, S-100, and CD34 indicated that both epithelial and mesenchymal components of the neoplasm had low proliferation. Alcian blue, periodic acid–Schiff, and trichrome stains showed an immature stromal component with no collagen formation. Based on the clinical, histologic, and immunophenotypic features, the tumor was identified as a locally infiltrative ameloblastic fibroma. PMID:22529141

Density functional theory for prediction of far-infrared vibrational frequencies: molecular crystals of astrophysical interest

NASA Astrophysics Data System (ADS)

Ennis, C.; Auchettl, R.; Appadoo, D. R. T.; Robertson, E. G.

2017-11-01

Solid-state density functional theory code has been implemented for the structure optimization of crystalline methanol, acetaldehyde and acetic acid and for the calculation of infrared frequencies. The results are compared to thin film spectra obtained from low-temperature experiments performed at the Australian Synchrotron. Harmonic frequency calculations of the internal modes calculated at the B3LYP-D3/m-6-311G(d) level shows higher deviation from infrared experiment than more advanced theory applied to the gas phase. Importantly for the solid-state, the simulation of low-frequency molecular lattice modes closely resembles the observed far-infrared features after application of a 0.92 scaling factor. This allowed experimental peaks to be assigned to specific translation and libration modes, including acetaldehyde and acetic acid lattice features for the first time. These frequency calculations have been performed without the need for supercomputing resources that are required for large molecular clusters using comparable levels of theory. This new theoretical approach will find use for the rapid characterization of intermolecular interactions and bonding in crystals, and the assignment of far-infrared spectra for crystalline samples such as pharmaceuticals and molecular ices. One interesting application may be for the detection of species of prebiotic interest on the surfaces of Kuiper-Belt and Trans-Neptunian Objects. At such locations, the three small organic molecules studied here could reside in their crystalline phase. The far-infrared spectra for their low-temperature solid phases are collected under planetary conditions, allowing us to compile and assign their most intense spectral features to assist future far-infrared surveys of icy Solar system surfaces.

Modeling glacial flow on and onto Pluto's Sputnik Planitia

NASA Astrophysics Data System (ADS)

Umurhan, O. M.; Howard, A. D.; Moore, J. M.; Earle, A. M.; White, O. L.; Schenk, P. M.; Binzel, R. P.; Stern, S. A.; Beyer, R. A.; Nimmo, F.; McKinnon, W. B.; Ennico, K.; Olkin, C. B.; Weaver, H. A.; Young, L. A.

2017-05-01

Observations of Pluto's surface made by the New Horizons spacecraft indicate present-day N2 ice glaciation in and around the basin informally known as Sputnik Planitia. Motivated by these observations, we have developed an evolutionary glacial flow model of solid N2 ice that takes into account its published thermophysical and rheological properties. This model assumes that glacial ice flows laminarly and has a low aspect ratio which permits a vertically integrated mathematical formulation. We assess the conditions for the validity of laminar N2 ice motion by revisiting the problem of the onset of solid-state buoyant convection of N2 ice for a variety of bottom thermal boundary conditions. Subject to uncertainties in N2 ice rheology, N2 ice layers are estimated to flow laminarly for thicknesses less than 400-1000 m. The resulting mass-flux formulation for when the N2 ice flows as a laminar dry glacier is characterized by an Arrhenius-Glen functional form. The flow model developed is used here to qualitatively answer some questions motivated by features we interpret to be a result of glacial flow found on Sputnik Planitia. We find that the wavy transverse dark features found along the northern shoreline of Sputnik Planitia may be a transitory imprint of shallow topography just beneath the ice surface suggesting the possibility that a major shoreward flow event happened relatively recently, within the last few hundred years. Model results also support the interpretation that the prominent darkened features resembling flow lobes observed along the eastern shoreline of the Sputnik Planitia basin may be the result of a basally wet N2 glacier flowing into the basin from the pitted highlands of eastern Tombaugh Regio.

Europa Ice Floes

NASA Technical Reports Server (NTRS)

1997-01-01

Jupiter's moon Europa, as seen in this image taken June 27, 1996 by NASA's Galileo spacecraft, displays features in some areas resembling ice floes seen in Earth's polar seas. Europa, about the size of Earth's moon, has an icy crust that has been severely fractured, as indicated by the dark linear, curved, and wedged-shaped bands seen here. These fractures have broken the crust into plates as large as 30 kilometers (18.5 miles) across. Areas between the plates are filled with material that was probably icy slush contaminated with rocky debris. Some individual plates were separated and rotated into new positions. Europa's density indicates that it has a shell of water ice thicker than 100 kilometers (about 60 miles), parts of which could be liquid. Currently, water ice could extend from the surface down to the rocky interior, but the features seen in this image suggest that motion of the disrupted icy plates was lubricated by soft ice or liquid water below the surface at the time of disruption. This image covers part of the equatorial zone of Europa and was taken from a distance of 156,000 kilometers (about 96,300 miles) by the Solid-state Imaging Subsystem on the Galileo spacecraft. North is to the right and the sun is nearly directly overhead. The area shown is about 510 by 989 kilometers (310-by-600 miles), and the smallest visible feature is about 1.6 kilometers (1 mile) across.

The Jet Propulsion Laboratory manages the Galileo mission for NASA's Office of Space Science, Washington, DC.

This image and other images and data received from Galileo are posted on the World Wide Web Galileo mission home page at http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at http:// www.jpl.nasa.gov/galileo/sepo.

Nitriles at Silica Interfaces Resemble Supported Lipid Bilayers.

PubMed

Berne, Bruce J; Fourkas, John T; Walker, Robert A; Weeks, John D

2016-09-20

Nitriles are important solvents not just for bulk reactions but also for interfacial processes such as separations, heterogeneous catalysis, and electrochemistry. Although nitriles have a polar end and a lipophilic end, the cyano group is not hydrophilic enough for these substances to be thought of as prototypical amphiphiles. This picture is now changing, as research is revealing that at a silica surface nitriles can organize into structures that, in many ways, resemble lipid bilayers. This unexpected organization may be a key component of unique interfacial behavior of nitriles that make them the solvents of choice for so many applications. The first hints of this lipid-bilayer-like (LBL) organization of nitriles at silica interfaces came from optical Kerr effect (OKE) experiments on liquid acetonitrile confined in the pores of sol-gel glasses. The orientational dynamics revealed by OKE spectroscopy suggested that the confined liquid is composed of a relatively immobile sublayer of molecules that accept hydrogen bonds from the surface silanol groups and an interdigitated, antiparallel layer that is capable of exchanging into the centers of the pores. This picture of acetonitrile has been borne out by molecular dynamics simulations and vibrational sum-frequency generation (VSFG) experiments. Remarkably, these simulations further indicate that the LBL organization is repeated with increasing disorder at least 20 Å into the liquid from a flat silica surface. Simulations and VSFG and OKE experiments indicate that extending the alkyl chain to an ethyl group leads to the formation of even more tightly packed LBL organization featuring entangled alkyl tails. When the alkyl portion of the molecule is a bulky t-butyl group, packing constraints prevent well-ordered LBL organization of the liquid. In each case, the surface-induced organization of the liquid is reflected in its interfacial dynamics. Acetonitrile/water mixtures are favored solvent systems for separations technologies such as hydrophilic interaction chromatography. Simulations had suggested that although a monolayer of water partitions to the silica surface in such mixtures, acetonitrile tends to associate with this monolayer. VSFG experiments reveal that, even at high water mole fractions, patches of well-ordered acetonitrile bilayers remain at the silica surface. Due to its ability to donate and accept hydrogen bonds, methanol also partitions to a silica surface in acetonitrile/methanol mixtures and can serve to take the place of acetonitrile in the sublayer closest to the surface. These studies reveal that liquid nitriles can exhibit an unexpected wealth of new organizational and dynamic behaviors at silica surfaces, and presumably at the surfaces of other chemically important materials as well. This behavior cannot be predicted from the bulk organization of these liquids. Our new understanding of the interfacial behavior of these liquids will have important implications for optimizing a wide range of chemical processes in nitrile solvents.

Building a profile of subjective well-being for social media users.

PubMed

Chen, Lushi; Gong, Tao; Kosinski, Michal; Stillwell, David; Davidson, Robert L

2017-01-01

Subjective well-being includes 'affect' and 'satisfaction with life' (SWL). This study proposes a unified approach to construct a profile of subjective well-being based on social media language in Facebook status updates. We apply sentiment analysis to generate users' affect scores, and train a random forest model to predict SWL using affect scores and other language features of the status updates. Results show that: the computer-selected features resemble the key predictors of SWL as identified in early studies; the machine-predicted SWL is moderately correlated with the self-reported SWL (r = 0.36, p < 0.01), indicating that language-based assessment can constitute valid SWL measures; the machine-assessed affect scores resemble those reported in a previous experimental study; and the machine-predicted subjective well-being profile can also reflect other psychological traits like depression (r = 0.24, p < 0.01). This study provides important insights for psychological prediction using multiple, machine-assessed components and longitudinal or dense psychological assessment using social media language.

Building a profile of subjective well-being for social media users

PubMed Central

Kosinski, Michal; Stillwell, David; Davidson, Robert L.

2017-01-01

Subjective well-being includes ‘affect’ and ‘satisfaction with life’ (SWL). This study proposes a unified approach to construct a profile of subjective well-being based on social media language in Facebook status updates. We apply sentiment analysis to generate users’ affect scores, and train a random forest model to predict SWL using affect scores and other language features of the status updates. Results show that: the computer-selected features resemble the key predictors of SWL as identified in early studies; the machine-predicted SWL is moderately correlated with the self-reported SWL (r = 0.36, p < 0.01), indicating that language-based assessment can constitute valid SWL measures; the machine-assessed affect scores resemble those reported in a previous experimental study; and the machine-predicted subjective well-being profile can also reflect other psychological traits like depression (r = 0.24, p < 0.01). This study provides important insights for psychological prediction using multiple, machine-assessed components and longitudinal or dense psychological assessment using social media language. PMID:29135991

Silica deposits on Mars with features resembling hot spring biosignatures at El Tatio in Chile

PubMed Central

Ruff, Steven W.; Farmer, Jack D.

2016-01-01

The Mars rover Spirit encountered outcrops and regolith composed of opaline silica (amorphous SiO2·nH2O) in an ancient volcanic hydrothermal setting in Gusev crater. An origin via either fumarole-related acid-sulfate leaching or precipitation from hot spring fluids was suggested previously. However, the potential significance of the characteristic nodular and mm-scale digitate opaline silica structures was not recognized. Here we report remarkably similar features within active hot spring/geyser discharge channels at El Tatio in northern Chile, where halite-encrusted silica yields infrared spectra that are the best match yet to spectra from Spirit. Furthermore, we show that the nodular and digitate silica structures at El Tatio that most closely resemble those on Mars include complex sedimentary structures produced by a combination of biotic and abiotic processes. Although fully abiotic processes are not ruled out for the Martian silica structures, they satisfy an a priori definition of potential biosignatures. PMID:27853166

Kinetics of Surface-Mediated Fibrillization of Amyloid-β (12-28) Peptides.

PubMed

Lin, Yi-Chih; Li, Chen; Fakhraai, Zahra

2018-04-17

Surfaces or interfaces are considered to be key factors in facilitating the formation of amyloid fibrils under physiological conditions. In this report, we study the kinetics of the surface-mediated fibrillization (SMF) of an amyloid-β fragment (Aβ 12-28 ) on mica. We employ a spin-coating-based drying procedure to control the exposure time of the substrate to a low-concentration peptide solution and then monitor the fibril growth as a function of time via atomic force microscopy (AFM). The evolution of surface-mediated fibril growth is quantitatively characterized in terms of the length histogram of imaged fibrils and their surface concentration. A two-dimensional (2D) kinetic model is proposed to numerically simulate the length evolution of surface-mediated fibrils by assuming a diffusion-limited aggregation (DLA) process along with size-dependent rate constants. We find that both monomer and fibril diffusion on the surface are required to obtain length histograms as a function of time that resemble those observed in experiments. The best-fit simulated data can accurately describe the key features of experimental length histograms and suggests that the mobility of loosely bound amyloid species is crucial in regulating the kinetics of SMF. We determine that the mobility exponent for the size dependence of the DLA rate constants is α = 0.55 ± 0.05, which suggests that the diffusion of loosely bound surface fibrils roughly depends on the inverse of the square root of their size. These studies elucidate the influence of deposition rate and surface diffusion on the formation of amyloid fibrils through SMF. The method used here can be broadly adopted to study the diffusion and aggregation of peptides or proteins on various surfaces to investigate the role of chemical interactions in two-dimensional fibril formation and diffusion.

Metabolic stratification driven by surface and subsurface interactions in a terrestrial mud volcano.

PubMed

Cheng, Ting-Wen; Chang, Yung-Hsin; Tang, Sen-Lin; Tseng, Ching-Hung; Chiang, Pei-Wen; Chang, Kai-Ti; Sun, Chih-Hsien; Chen, Yue-Gau; Kuo, Hung-Chi; Wang, Chun-Ho; Chu, Pao-Hsuan; Song, Sheng-Rong; Wang, Pei-Ling; Lin, Li-Hung

2012-12-01

Terrestrial mud volcanism represents the prominent surface geological feature, where fluids and hydrocarbons are discharged along deeply rooted structures in tectonically active regimes. Terrestrial mud volcanoes (MVs) directly emit the major gas phase, methane, into the atmosphere, making them important sources of greenhouse gases over geological time. Quantification of methane emission would require detailed insights into the capacity and efficiency of microbial metabolisms either consuming or producing methane in the subsurface, and establishment of the linkage between these methane-related metabolisms and other microbial or abiotic processes. Here we conducted geochemical, microbiological and genetic analyses of sediments, gases, and pore and surface fluids to characterize fluid processes, community assemblages, functions and activities in a methane-emitting MV of southwestern Taiwan. Multiple lines of evidence suggest that aerobic/anaerobic methane oxidation, sulfate reduction and methanogenesis are active and compartmentalized into discrete, stratified niches, resembling those in marine settings. Surface evaporation and oxidation of sulfide minerals are required to account for the enhanced levels of sulfate that fuels subsurface sulfate reduction and anaerobic methanotrophy. Methane flux generated by in situ methanogenesis appears to alter the isotopic compositions and abundances of thermogenic methane migrating from deep sources, and to exceed the capacity of microbial consumption. This metabolic stratification is sustained by chemical disequilibria induced by the mixing between upward, anoxic, methane-rich fluids and downward, oxic, sulfate-rich fluids.

Metabolic stratification driven by surface and subsurface interactions in a terrestrial mud volcano

PubMed Central

Cheng, Ting-Wen; Chang, Yung-Hsin; Tang, Sen-Lin; Tseng, Ching-Hung; Chiang, Pei-Wen; Chang, Kai-Ti; Sun, Chih-Hsien; Chen, Yue-Gau; Kuo, Hung-Chi; Wang, Chun-Ho; Chu, Pao-Hsuan; Song, Sheng-Rong; Wang, Pei-Ling; Lin, Li-Hung

2012-01-01

Terrestrial mud volcanism represents the prominent surface geological feature, where fluids and hydrocarbons are discharged along deeply rooted structures in tectonically active regimes. Terrestrial mud volcanoes (MVs) directly emit the major gas phase, methane, into the atmosphere, making them important sources of greenhouse gases over geological time. Quantification of methane emission would require detailed insights into the capacity and efficiency of microbial metabolisms either consuming or producing methane in the subsurface, and establishment of the linkage between these methane-related metabolisms and other microbial or abiotic processes. Here we conducted geochemical, microbiological and genetic analyses of sediments, gases, and pore and surface fluids to characterize fluid processes, community assemblages, functions and activities in a methane-emitting MV of southwestern Taiwan. Multiple lines of evidence suggest that aerobic/anaerobic methane oxidation, sulfate reduction and methanogenesis are active and compartmentalized into discrete, stratified niches, resembling those in marine settings. Surface evaporation and oxidation of sulfide minerals are required to account for the enhanced levels of sulfate that fuels subsurface sulfate reduction and anaerobic methanotrophy. Methane flux generated by in situ methanogenesis appears to alter the isotopic compositions and abundances of thermogenic methane migrating from deep sources, and to exceed the capacity of microbial consumption. This metabolic stratification is sustained by chemical disequilibria induced by the mixing between upward, anoxic, methane-rich fluids and downward, oxic, sulfate-rich fluids. PMID:22739492

Active high-resolution seismic tomography of compressional wave velocity and attenuation structure at Medicine Lake Volcano, northern California Cascade Range

USGS Publications Warehouse

Evans, J.R.; Zucca, J.J.

1988-01-01

Medicine Lake volcano is a basalt through rhyolite shield volcano of the Cascade Range, lying east of the range axis. The Pg wave from eight explosive sources which has traveled upward through the target volume to a dense array of 140 seismographs provides 1- to 2-km resolution in the upper 5 to 7 km of the crust beneath the volcano. The experiment tests the hypothesis that Cascade Range volcanoes of this type are underlain only by small silicic magma chambers. We image a low-velocity low-Q region not larger than a few tens of cubic kilometers in volume beneath the summit caldera, supporting the hypothesis. A shallower high-velocity high-density feature, previously known to be present, is imaged for the first time in full plan view; it is east-west elongate, paralleling a topographic lineament between Medicine Lake volcano and Mount Shasta. Differences between this high-velocity feature and the equivalent feature at Newberry volcano, a volcano in central regon resembling Medicine Lake volcano, may partly explain the scarcity of surface hydrothermal features at Medicine Lake volcano. A major low-velocity low-Q feature beneath the southeast flank of the volcano, in an area with no Holocene vents, is interpreted as tephra, flows, and sediments from the volcano deeply ponded on the downthrown side of the Gillem fault. A high-Q normal-velocity feature beneath the north rim of the summit caldera may be a small, possibly hot, subsolidus intrusion. A high-velocity low-Q region beneath the eastern caldera may be an area of boiling water between the magma chamber and the ponded east flank material. -from Authors

Mechanical modelling of tooth wear

PubMed Central

Kallonen, Aki

2016-01-01

Different diets wear teeth in different ways and generate distinguishable wear and microwear patterns that have long been the basis of palaeodiet reconstructions. Little experimental research has been performed to study them together. Here, we show that an artificial mechanical masticator, a chewing machine, occluding real horse teeth in continuous simulated chewing (of 100 000 chewing cycles) is capable of replicating microscopic wear features and gross wear on teeth that resemble wear in specimens collected from nature. Simulating pure attrition (chewing without food) and four plant material diets of different abrasives content (at n = 5 tooth pairs per group), we detected differences in microscopic wear features by stereomicroscopy of the chewing surface in the number and quality of pits and scratches that were not always as expected. Using computed tomography scanning in one tooth per diet, absolute wear was quantified as the mean height change after the simulated chewing. Absolute wear increased with diet abrasiveness, originating from phytoliths and grit. In combination, our findings highlight that differences in actual dental tissue loss can occur at similar microwear patterns, cautioning against a direct transformation of microwear results into predictions about diet or tooth wear rate. PMID:27411727

Polypoid dermal hemangiopericytoma: a case report.

PubMed

Pollock, A M; Sweeney, E C

1998-10-01

A polypoid dermal lesion with histologic, immunohistochemical, and ultrastructural features of hemangiopericytoma is described. Such tumors, arising in the dermis, are exceptionally rare, and whereas the tumor bears some resemblance to meningioma-like tumors of the skin and the well-recognized animal counterpart, canine hemangiopericytoma, it is histologically distinct.

Infrared spectroscopy of interplanetary dust in the laboratory

NASA Technical Reports Server (NTRS)

Fraundorf, P.; Patel, R. I.; Freeman, J. J.

1981-01-01

A mount containing three crushed chondritic interplanetary dust particles (IDPs) collected in the earth's stratosphere and subjected to infrared spectroscopic measurements shows features near 1000 and 500/cm, suggesting crystalline pyroxene rather than crystalline olivine, amorphous olivine, or meteoritic clay minerals. Chondritic IDP structural diversity and atmospheric heating effects must be considered when comparing this spectrum with interplanetary and cometary dust astrophysical spectra. TEM and infrared observations of one member of the rare subset of IDPs resembling hydrated carbonaceous chondrite matrix material shows a close infrared spectrum resemblance between 4000 and 400/cm to the C2 meteorite Murchison. TEM observations suggest that this class of particles may be used as an atmospheric entry heating-process thermometer.

Adult human metapneumonovirus (hMPV) pneumonia mimicking Legionnaire's disease.

PubMed

Cunha, Burke A; Irshad, Nadia; Connolly, James J

2016-01-01

In adults hospitalized with viral pneumonias the main differential diagnostic consideration is influenza pneumonia. The respiratory viruses causing viral influenza like illnesses (ILIs), e.g., RSV may closely resemble influenza. Rarely, extrapulmonary findings of some ILIs may resemble Legionnaire's disease (LD), e.g., adenovirus, human parainfluenza virus (HPIV-3). We present a most unusual case of human metapneumonovirus pneumonia (hMPV) with some characteristic extrapulmonary findings characteristic of LD, e.g., relative bradycardia, as well as mildly elevated serum transaminases and hyphosphatemia. We believe this is the first reported case of hMPV pneumonia in a hospitalized adult that had some features of LD. Copyright © 2016 Elsevier Inc. All rights reserved.

Depression or Endocrine Disorder?: What Mental Health Counselors Need to Know about Hypothyroidism.

ERIC Educational Resources Information Center

Stanley, Paula Helen

1997-01-01

Describes hypothyroidism, an endocrine disorder characterized by symptoms that resemble those of depression. Discusses features of the disorder, types and grades of hypothyroidism, causes, valuative techniques for the disorder, and implications of hypothyroidism in counseling and in treating patients suffering from this disorder. (RJM)

Modula-3 Report.

ERIC Educational Resources Information Center

Cardelli, Luca; And Others

Designed by the DEC Systems Research Center and the Olivetti Research Center, the programming language Modula-3 descends from Mesa, Modula-2, Cedar, and Module-2+, and resembles Object Pascal, Oberon, and Euclid. A notable feature of this language family is the use of modules to delineate the separation between the implementation and the use of…

Melorheostosis involving the craniofacial skeleton.

PubMed

Ethunandan, Madanagopalan; Khosla, Nalin; Tilley, Elizabeth; Webb, Andrew

2004-11-01

Melorheostosis is a rare bone disorder, usually affecting the long bones and adjacent soft tissue. It was originally described by Leri and Joanny in 1922, after its classic x-ray features of flowing hyperostosis resembling dripping candle wax. There have been fewer than 10 reported cases of craniofacial involvement, and in most instances these have also involved the appendicular skeleton. The authors report a case of melorheostosis with isolated craniofacial involvement, describe the clinical course and radiologic and histologic features, and review the pertinent literature.

Variation in diffusion of gases through PDMS due to plasma surface treatment and storage conditions.

PubMed

Markov, Dmitry A; Lillie, Elizabeth M; Garbett, Shawn P; McCawley, Lisa J

2014-02-01

Polydimethylsiloxane (PDMS) is a commonly used polymer in the fabrication of microfluidic devices due to such features as transparency, gas permeability, and ease of patterning with soft lithography. The surface characteristics of PDMS can also be easily changed with oxygen or low pressure air plasma converting it from a hydrophobic to a hydrophilic state. As part of such a transformation, surface methyl groups are removed and replaced with hydroxyl groups making the exposed surface to resemble silica, a gas impermeable substance. We have utilized Platinum(II)-tetrakis(pentaflourophenyl)porphyrin immobilized within a thin (~1.5 um thick) polystyrene matrix as an oxygen sensor, Stern-Volmer relationship, and Fick's Law of simple diffusion to measure the effects of PDMS composition, treatment, and storage on oxygen diffusion through PDMS. Results indicate that freshly oxidized PDMS showed a significantly smaller diffusion coefficient, indicating that the SiO2 layer formed on the PDMS surface created an impeding barrier. This barrier disappeared after a 3-day storage in air, but remained significant for up to 3 weeks if PDMS was maintained in contact with water. Additionally, higher density PDMS formulation (5:1 ratio) showed similar diffusion characteristics as normal (10:1 ratio) formulation, but showed 60 % smaller diffusion coefficient after plasma treatment that never recovered to pre-treatment levels even after a 3-week storage in air. Understanding how plasma surface treatments contribute to oxygen diffusion will be useful in exploiting the gas permeability of PDMS to establish defined normoxic and hypoxic oxygen conditions within microfluidic bioreactor systems.

Variation in diffusion of gases through PDMS due to plasma surface treatment and storage conditions

PubMed Central

Markov, Dmitry A.; Lillie, Elizabeth M.; Garbett, Shawn P.; McCawley, Lisa J.

2013-01-01

Polydimethylsiloxane (PDMS) is a commonly used polymer in the fabrication of microfluidic devices due to such features as transparency, gas permeability, and ease of patterning with soft lithography. The surface characteristics of PDMS can also be easily changed with oxygen or low pressure air converting it from a hydrophobic to a hydrophilic state. As part of such a transformation, surface methyl groups are removed and replaced with hydroxyl groups making the exposed surface to resemble silica, a gas impermeable substance. We have utilized Platinum(II)-tetrakis(pentaflourophenyl)porphyrin immobilized within a thin (~1.5 um thick) polystyrene matrix as an oxygen sensor, Stern-Volmer relationship, and Fick's Law of simple diffusion to measure the effects of PDMS composition, treatment, and storage on oxygen diffusion through PDMS. Results show that freshly oxidized PDMS showed a significantly smaller diffusion coefficient, indicating that the SiO2 layer formed on the PDMS surface created an impeding barrier. This barrier disappeared after a three-day storage in air, but remained significant for up to three weeks if PDMS was maintained in contact with water. Additionally, higher density PDMS formulation (5:1 ratio) showed similar diffusion characteristics as normal (10:1 ratio) formulation, but showed 60% smaller diffusion coefficient after plasma treatment that never recovered to pre-treatment levels even after a three-week storage in air. Understanding how plasma surface treatments contribute to oxygen diffusion will be useful in exploiting the gas permeability of PDMS to establish defined normoxic and hypoxic oxygen conditions within microfluidic bioreactor systems. PMID:24065585

Features versus context: An approach for precise and detailed detection and delineation of faces and facial features.

PubMed

Ding, Liya; Martinez, Aleix M

2010-11-01

The appearance-based approach to face detection has seen great advances in the last several years. In this approach, we learn the image statistics describing the texture pattern (appearance) of the object class we want to detect, e.g., the face. However, this approach has had limited success in providing an accurate and detailed description of the internal facial features, i.e., eyes, brows, nose, and mouth. In general, this is due to the limited information carried by the learned statistical model. While the face template is relatively rich in texture, facial features (e.g., eyes, nose, and mouth) do not carry enough discriminative information to tell them apart from all possible background images. We resolve this problem by adding the context information of each facial feature in the design of the statistical model. In the proposed approach, the context information defines the image statistics most correlated with the surroundings of each facial component. This means that when we search for a face or facial feature, we look for those locations which most resemble the feature yet are most dissimilar to its context. This dissimilarity with the context features forces the detector to gravitate toward an accurate estimate of the position of the facial feature. Learning to discriminate between feature and context templates is difficult, however, because the context and the texture of the facial features vary widely under changing expression, pose, and illumination, and may even resemble one another. We address this problem with the use of subclass divisions. We derive two algorithms to automatically divide the training samples of each facial feature into a set of subclasses, each representing a distinct construction of the same facial component (e.g., closed versus open eyes) or its context (e.g., different hairstyles). The first algorithm is based on a discriminant analysis formulation. The second algorithm is an extension of the AdaBoost approach. We provide extensive experimental results using still images and video sequences for a total of 3,930 images. We show that the results are almost as good as those obtained with manual detection.

Distinct growth of the nasomaxillary complex in Au. sediba.

PubMed

Lacruz, Rodrigo S; Bromage, Timothy G; O'Higgins, Paul; Toro-Ibacache, Viviana; Warshaw, Johanna; Berger, Lee R

2015-10-15

Studies of facial ontogeny in immature hominins have contributed significantly to understanding the evolution of human growth and development. The recently discovered hominin species Autralopithecus sediba is represented by a well-preserved and nearly complete facial skeleton of a juvenile (MH1) which shows a derived facial anatomy. We examined MH1 using high radiation synchrotron to interpret features of the oronasal complex pertinent to facial growth. We also analyzed bone surface microanatomy to identify and map fields of bone deposition and bone resorption, which affect the development of the facial skeleton. The oronasal anatomy (premaxilla-palate-vomer architecture) is similar to other Australopithecus species. However surface growth remodeling of the midface (nasomaxillary complex) differs markedly from Australopithecus, Paranthropus, early Homo and from KNM-WT 15000 (H. erectus/ergaster) showing a distinct distribution of vertically disposed alternating depository and resorptive fields in relation to anterior dental roots and the subnasal region. The ontogeny of the MH1 midface superficially resembles some H. sapiens in the distribution of remodeling fields. The facial growth of MH1 appears unique among early hominins representing an evolutionary modification in facial ontogeny at 1.9 my, or to changes in masticatory system loading associated with diet.

Predictability of ENSO, the QBO, and European winter 2015/16

NASA Astrophysics Data System (ADS)

Scaife, A. A.; Ineson, S.; Ruth, C.; Dunstone, N. J.; Fereday, D.; Folland, C. K.; Good, E.; Gordon, M.; Hermanson, L.; Karpechko, A.; Knight, J. R.; MacLachlan, C.; Maidens, A. V.; Peterson, A.; Slingo, J.; Smith, D.; Walker, B.

2016-12-01

The northern winter of 2015/16 gave rise to the strongest El Niño event since 1997/8. Central and eastern Pacific sea surface temperature anomalies exceeded three degrees and closely resembled the strong El Niño in winter of 1982/3. A second feature of this winter was a strong westerly phase of the Quasi-Biennial Oscillation and very strong winds in the stratospheric polar night jet. At the surface, intense extratropical circulation anomalies occurred in both the North Pacific and North Atlantic that were consistent with known teleconnections to the observed phases of ENSO and the QBO. The North Atlantic Oscillation was very positive in the early winter period (Nov-Dec) and was more blocked in the late winter. Initialised climate predictions were able to capture these signals at seasonal lead times. This case study adds to the evidence that north Atlantic circulation exhibits predictability on seasonal timescales, and in this case we show that even aspects of the detailed pattern and sub-seasonal evolution were predicted, providing warning of increased risk of extreme events such as the intense rainfall which caused extreme flooding in the UK in December.

A new species of Entobdella Blainville in Lamarck, 1818 (Monogenea: Capsalidae: Entobdellinae) from the Greenland halibut, Reinhardtius hippoglossoides.

PubMed

Kearn, Graham; Karlsbakk, Egil; Evans-Gowing, Richard; Gerasev, Pavel

2015-09-01

A previously undescribed species of Entobdella is reported from the skin of the Greenland halibut, Reinhardtius hippoglossoides (Pleuronectiformes, Pleuronectidae). Entobdella whittingtoni sp. nov. differs from other species of Entobdella, including skin parasites of the related pleuronectids Hippoglossus hippoglossus (Atlantic halibut) and H. stenolepis (Pacific halibut), in lacking papillae on the ventral surface of the haptor. Other characteristics of E. whittingtoni are as follows: the absence of vitelline follicles lateral to the pharynx thereby exposing gut caeca in this region of whole mounts; the presence of a circular feature of unknown function, resembling a rosette in sections, attached to the wall of the internal male accessory reservoir; the lack of eyes. Papillae are also absent from the ventral surface of the haptor of the gill-parasitic entobdelline Branchobdella pugetensis, a gill parasite of the pleuronectid Atheresthes stomias. This raises the question as to whether this gill parasite has evolved from a skin-parasitic ancestor similar to E. whittingtoni. An answer to this question requires a more detailed study of the male reproductive apparatus of B. pugetensis and the use of molecular techniques to explore the relationship between B. pugetensis and E. whittingtoni.

Laser speckle and skin cancer: skin roughness assessment

NASA Astrophysics Data System (ADS)

Lee, Tim K.; Tchvialeva, Lioudmila; Zeng, Haishan; McLean, David I.; Lui, Harvey

2009-10-01

Incidence of skin cancer has been increasing rapidly since the last few decades. Non-invasive optical diagnostic tools may improve the diagnostic accuracy. In this paper, skin structure, skin cancer statistics and subtypes of skin cancer are briefly reviewed. Among the subtypes, malignant melanoma is the most aggressive and dangerous; early detection dramatically improves the prognosis. Therefore, a non-invasive diagnostic tool for malignant melanoma is especially needed. In addition, in order for the diagnostic tool to be useful, it must be able to differentiate melanoma from common skin conditions such as seborrheic keratosis, a benign skin disease that resembles melanoma according to the well known clinical-assessment ABCD rule. The key diagnostic feature between these two diseases is surface roughness. Based on laser speckle contrast, our research team has recently developed a portable, optical, non-invasive, in-vivo diagnostic device for quantifying skin surface roughness. The methodology of our technique is described in details. Examining the preliminary data collected in a pilot clinical study for the prototype, we found that there was a difference in roughness between melanoma and seborrheic keratosis. In fact, there was a perfect cutoff value for the two diseases based on our initial data.

Synergistic Catalysis between Pd and Fe in Gas Phase Hydrodeoxygenation of m-Cresol

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

Hong, Yongchun; Zhang, He; Sun, Junming

2014-10-31

In this work, a series of Pd/Fe2O3 catalysts were synthesized, characterized, and evaluated for the hydrodeoxygenation (HDO) of m-cresol. It was found that the addition of Pd remarkably promotes the catalytic activity of Fe while the product distributions resemble that of monometallic Fe catalyst, showing high selectivity towards the production of toluene (C-O cleavage without saturation of aromatic ring and C-C cleavage). Reduced catalysts featured with Pd patches on the top of reduced Fe nanoparticle surface, and the interaction between Pd and Fe was further confirmed using X-ray photoelectron spectroscopy (XPS), scanning transmission electron microscopy (STEM) and X-ray absorption nearmore » edge fine structure (XANES). A possible mechanism, including Pd assisted H2 dissociation and Pd facilitated stabilization of metallic Fe surface as well as Pd enhanced product desorption, is proposed to be responsible for the high activity and HDO selectivity in Pd-Fe catalysts. The synergic catalysis derived from Pd-Fe interaction found in this work was proved to be applicable to other precious metal promoted Fe catalysts, providing a promising strategy for future design of highly active and selective HDO catalysts.« less

Centuries of intense surface melt on Larsen C Ice Shelf

NASA Astrophysics Data System (ADS)

Bevan, Suzanne L.; Luckman, Adrian; Hubbard, Bryn; Kulessa, Bernd; Ashmore, David; Kuipers Munneke, Peter; O'Leary, Martin; Booth, Adam; Sevestre, Heidi; McGrath, Daniel

2017-12-01

Following a southward progression of ice-shelf disintegration along the Antarctic Peninsula (AP), Larsen C Ice Shelf (LCIS) has become the focus of ongoing investigation regarding its future stability. The ice shelf experiences surface melt and commonly features surface meltwater ponds. Here, we use a flow-line model and a firn density model (FDM) to date and interpret observations of melt-affected ice layers found within five 90 m boreholes distributed across the ice shelf. We find that units of ice within the boreholes, which have densities exceeding those expected under normal dry compaction metamorphism, correspond to two climatic warm periods within the last 300 years on the Antarctic Peninsula. The more recent warm period, from the 1960s onwards, has generated distinct sections of dense ice measured in two boreholes in Cabinet Inlet, which is close to the Antarctic Peninsula mountains - a region affected by föhn winds. Previous work has classified these layers as refrozen pond ice, requiring large quantities of mobile liquid water to form. Our flow-line model shows that, whilst preconditioning of the snow began in the late 1960s, it was probably not until the early 1990s that the modern period of ponding began. The earlier warm period occurred during the 18th century and resulted in two additional sections of anomalously dense ice deep within the boreholes. The first, at 61 m in one of our Cabinet Inlet boreholes, consists of ice characteristic of refrozen ponds and must have formed in an area currently featuring ponding. The second, at 69 m in a mid-shelf borehole, formed at the same time on the edge of the pond area. Further south, the boreholes sample ice that is of an equivalent age but which does not exhibit the same degree of melt influence. This west-east and north-south gradient in the past melt distribution resembles current spatial patterns of surface melt intensity.

Laboratory Thermal Infrared and Visible to Near-Infrared Spectral Analysis of Chert

NASA Astrophysics Data System (ADS)

McDowell, M. L.; Hamilton, V. E.

2007-12-01

Though basaltic materials dominate the composition of the Martian surface, a material with a relatively high silica component in an area of Eos Chasma was reported by [1] from thermal infrared (TIR) data. The spectrum of the silica phase resembles quartz or chert, but with the existing information it is difficult to tell which phase best fits the observations. Though quartz, chert, and amorphous silica are chemically identical (SiO2), their physical differences (e.g., microstructures) result in different TIR spectral characteristics. Previous studies have analyzed a limited number of chert samples using emission infrared spectroscopy [2] and transmission infrared spectroscopy [3]. We continue these preliminary studies with an investigation aiming to more completely understand and document the variation in spectral character of cherts. This knowledge may help to identify the silica phase in Eos Chasma and any future discoveries. Our study includes a more extensive sampling of geologic chert in hand sample (>15 samples) with various sources, methods of formation, surface textures, and crystallinities. We analyzed their visible to near-infrared (VNIR) reflectance spectra, as well as spectral features in TIR emission spectra. We measured multiple locations on each sample to determine spectral homogeneity across the sample and between various orientations. Where possible, natural, cut, and recently fractured surfaces were measured. We compared the collected TIR spectra for similarities and differences in shape and spectral contrast within each sample and between samples that may relate to variations in the samples' structure (e.g. crystallinity, and surface texture). VNIR measurements show features indicative of non-silica phases and water that may be present in the cherts. [1] Hamilton, V.E. (2005) Eos Trans. AGU, Fall Meeting Suppl., Abstract P24A-08. [2] Michalski, J.R. (2005) PhD Diss., ASU, Tempe. [3] Long, D. G. et al. (2001) Canadian Archaeological Assoc., 33rd Meeting.

Rayleigh wave acoustic emission during crack propagation in steel

NASA Astrophysics Data System (ADS)

Horne, Michael R.

2003-07-01

An investigation was conducted of the existence of seismic surface pulses (SSP) on crack faces in near-failure fatigue. An SSP has components of various modes of wave propagation. The component with the largest amplitude is a Rayleigh surface wave pulse. The possibility that these surface modes have much higher amplitudes than bulk modes of acoustic emission (AE) was illustrated by an idealized thought experiment relating an SSP on a half-space to the response of crack faces to crack extension. A number of aspects of AE monitoring in finite objects were investigated. Attributes of surface wave propagation on the edge of a specimen were found to be easier to monitor than other modes of wave propagation. Wavelet analysis was used to compare the characteristics of brittle AE with other sources. A new testing paradigm was developed to reduce interference from secondary sources of AE and enhance the investigation of AE from critical crack behavior. Unique specimen design features were developed, data acquisition features sought and validated, a dead weight load frame was modified, and data analysis procedures were developed. Criteria based on velocity, frequency content, amplitude and shape were devised to determine if an AE event is an SSP. The tests were designed to mimic load conditions on structures such as bridges and hence investigate the difference between AE generated in field conditions and that of typical laboratory conditions. Varieties of steel, from very ductile to very brittle, were tested. It was concluded that plastic zone formation, considered a secondary source of AE, was found not to interfere with the SSP activity. The SSP was found experimentally to have 2-3 times the amplitude of the bulk wave AE. The lack of sufficient AE did not allow for determination of conclusive changes in the AE as the specimens approached failure. However, it was found that brittle crack extension in fatigue and ductile failure can produce wave propagation resembling the SSP.

Rayleigh wave acoustic emission during crack propagation in steel

NASA Astrophysics Data System (ADS)

Horne, Michael R.

An investigation was conducted of the existence of seismic surface pulses (SSP) on crack faces in near-failure fatigue. An SSP has components of various modes of wave propagation. The component with the largest amplitude is a Rayleigh surface wave pulse. The possibility that these surface modes have much higher amplitudes than bulk modes of acoustic emission (AE) was illustrated by an idealized thought experiment relating an SSP on a half-space to the response of crack faces to crack extension. A number of aspects of AE monitoring in finite objects were investigated. Attributes of surface wave propagation on the edge of a specimen were found to be easier to monitor than other modes of wave propagation. Wavelet analysis was used to compare the characteristics of brittle AE with other sources. A new testing paradigm was developed to reduce interference from secondary sources of AE and enhance the investigation of AE from critical crack behavior. Unique specimen design features were developed, data acquisition features sought and validated, a dead weight load frame was modified, and data analysis procedures were developed. Criteria based on velocity, frequency content, amplitude and shape were devised to determine if an AE event is an SSP. The tests were designed to mimic load conditions on structures such as bridges and hence investigate the difference between AE generated in field conditions and that of typical laboratory conditions. Varieties of steel, from very ductile to very brittle, were tested. It was concluded that plastic zone formation, considered a secondary source of AE, was found not to interfere with the SSP activity. The SSP was found experimentally to have 2-3 times the amplitude of the bulk wave AE. The lack of sufficient AE did not allow for determination of conclusive changes in the AE as the specimens approached failure. However, it was found that brittle crack extension in fatigue and ductile failure can produce wave propagation resembling the SSP.

Integrated gas turbine engine-nacelle

NASA Technical Reports Server (NTRS)

Adamson, A. P.; Sargisson, D. F.; Stotler, C. L., Jr. (Inventor)

1977-01-01

A nacelle for use with a gas turbine engine is presented. An integral webbed structure resembling a spoked wheel for rigidly interconnecting the nacelle and engine, provides lightweight support. The inner surface of the nacelle defines the outer limits of the engine motive fluid flow annulus while the outer surface of the nacelle defines a streamlined envelope for the engine.

Are the Basins of Tui Regio and Hotei Arcus Sites of Former Titanian Seas?

NASA Technical Reports Server (NTRS)

Moore, Jeffrey Morgan; Howard, Alan

2012-01-01

Features observed in the basins of Tui Regio and Hotei Arcus on Titan have attracted the attention of the Cassini-era investigators. At both locations, VIMS observed discrete 5-micron bright approx.500-km wide features described as lobate in shape. Several studies have proposed that these materials are cryo-volcanic flows; in the case of the Hotei Arcus feature this inference was buttressed with SAR RADAR images showing bright and dark patches with lobate margins. We propose an alternative explanation. First we note that all landforms on Titan that are unambiguously identifiable can be explained by exogenic processes (aeolian, fluvial, impact cratering, and mass wasting). Suggestions of endogenically produced cryovolcanic constructs and flows have, without exception, lacked conclusive diagnostic evidence. Recently published topographic profiles across Tui Regio and the lobate feature region north of Hotei Arcus indicate these features appear to occur in large regional basins, at least along the direction of the profiles. SAR images show that the terrains surrounding both 5-micron bright features exhibit fluvial networks that appear to converge and debauch into the probable basins. The 5-micron bright features themselves correspond to fields of discrete radar-bright depressions whose bounding edges are commonly rounded and cumulate in planform in SAR images. These fields of discrete radar-bright depressions strongly resemble fields of features seen at Titan s high latitudes usually attributed to be dry lakes. Thus the combination of (1) the resemblance to high-latitude dry lakes, (2) location in the centers of probable regional depressions, and (3) convergence of fluvial networks are inferred by us to best explain the 5-micron bright regions at Tui Regio and Hotei Arcus as sites of dry seas or at least paleolake clusters. Such equatorial seas, if real, may be evidence of substantially larger inventories of liquid alkanes in Titan s past.

Possible sea sediments due to glaciofluvial activity in Elysium Planitia, Mars

NASA Astrophysics Data System (ADS)

Nussbaumer, J.

Observations of fluvial morphologies in southern Elysium Planitia strongly supports the hypothesis that water substantially affected this region during the relatively recent geologic past. As of yet, however, the extent of a standing body of water has been speculative. The observation of zig-zag features potentially analogous to those observed near the Wadden Sea on Earth [see 1] may help show in more detail the origin, activity, and fate of water in this region of Mars. These terrestrial analogs could constrain environmental scenarios concerning the formation of these features. We present a geomorphologic map of central Elysium Planitia, that aids in our interpretation of potentially site-specific depositional/erosional morphologies. Positive relief zig-zag features within the Medusae Fossae Formation (Themis Image V05875001) resemble similar structures on Earth observed at shorelines of flat regions. Glaciofluvial activity is indicated by linear features resembling straight glacial flutings, which could form aeolian yardangs subsequently. The flutings are associated with branches of inverted fluvial channels (Images Themis V05588002, MOC e1800307). Their excavated positive relief (height ~40 m) indicates, that the adjacent material was eroded by sublimation or aeolian activity. The channels possibly resemble ice marginal channels. A high resolution Digital Terrain Model of one of the channels suggests, that one channel is possibly running upslope. Fluvial processes could have operated at one location at one time, and glacial processes at another location at another time [2]. A glacial drainage system [see 3] is a possible terrestrial analog for one inverted fluvial channel on Mars (Themis Image V05875001). Flutings occur on the foreland of many glaciers and their length may provide important evidence for rapid advance over substantial distances. Flutings are the product of subglacial erosion and transport processes [4]. By assigning the different environmental conditions to their geographic and stratigraphic positions, we intend to develop a geologic history of the central Elysium region. Ackowledgements for helpful contributions: D. Burr, J. Skinner, R. Williams References: [1] Tomei, K. (2004), Scriptum Publishers, 312 pp. [2] Burr et al. (2006) LPS XXXVII, #1367. [3] Evans, D. (2005), Hodder Arnold, 544pp. [4] Sharp M. J. (1984) Journal of Glaciology 82-93.

Multiple palaeokarst horizons in the Lower Palaeozoic of Baltoscandia challenging the dogma of a deep epicontinental sea

NASA Astrophysics Data System (ADS)

Lehnert, O.; Calner, M.; Ahlberg, P.; Harper, D. A.

2012-04-01

Several prominent palaeokarst surfaces have recently been detected in the Cambro-Ordovician sedimentary succession of Sweden. The oldest palaeokarst was found in autumn 2011 in Västergötland. An irregular palaeokarst cave with a breccia fill yielding large, angular Orsten clasts in a dark mud- to wackestone matrix is exposed beneath a karstic surface in the Cambrian Alum Shale Formation at Kakeled Quarry, Kinnekulle. The karstic surface occurs near the top of the Kakeled Limestone Bed that ranges from the upper Agnostus pisiformis into the Ctenopyge tumida Zone. The base of the cave is more than 1.4 m below this unconformity. A mass occurrence of Orusia lenticularis, a shallow-water brachiopod originally settling on hard substrates, in the karst pockets reflects deposition of the conglomeratic cover in extremely shallow marine environments. We interpret the widespread Orusia occurrences together with a brecciated or conglomeratic interval above an irregular surface in various Swedish locations as evidence for transgression after a major regression, regionally exposing the sea-floors of the Alum Shale Basin. A slightly younger karst surface is exposed in Tomten Quarry at Torbjörntorp, Västergötland. This resembles "Schrattenkalk" in the quarry wall but rock slabs cut vertical and parallel to bedding display a karren system, which reconstructed in 3D resembles "Napfkarren" or cockling features. Trilobites of the Ctenopyge bisulcata and C. linnarssoni zones have been recovered from the orsten bed just below the base of a 1-2 cm thick and irregular glauconitic packstone layer of the Bjørkåsholmen Formation (upper P. deltifer conodont Zone). The huge stratigraphic gap comprises the six uppermost trilobite zones of the Furongian plus most of the Tremadocian. Darriwilian conodonts with reworked older material within a limestone bed slightly above the glauconitic packstone point to yet another substantial gap in the succession. In the new Tingskullen core from northeastern Öland a karstic surface with grikes and evidence of repeated exposure occurs on the top of the upper Djupvik Formation (equivalent to the Bjørkåsholmen Formation). This palaeokarst is covered by the Töyen Formation and represents erosion and karstification during the global Ceratopyge Regressive Event (CRE). Higher up in the Ordovician of Öland, the lower Dapingian Blommiga Bladet hardground complex (Flowery Sheet) preserves karst morphologies. It can be correlated by means of the typical large borings of Gastrochaenolites oelandicus across most of Baltoscandia, including the Siljan district (new observations). An unconformity has recently been identified on top of the Skagen Formation in the Röstånga core from Scania (Skåne). This surface yield solution features possibly of subaerial origin and correlates with a conglomerate at the upper boundary of the same formation in the Borenshult core (Östergötland). Lastly, a prominent, basin-wide palaeokarst horizon in the Upper Ordovician Slandrom Limestone has been recently documented in detail. The multiple karst horizons in the Cambro-Silurian of Sweden imply subaerial exposure, and even locally soil-forming processes, during major regressions. Their preservation implies rapid burial and transgression. The common evidence for palaeokarst together with other sedimentary and biotic proxies of extremely shallow-water, challenge earlier models favouring a stable and deep basin.

Woodbridge Middle School: Getting Better Together

ERIC Educational Resources Information Center

Principal Leadership, 2012

2012-01-01

This article features Woodbridge Middle School, a middle school in Woodbridge, Virginia, which has always celebrated a tradition of excellence. Today's Woodbridge Middle School in no way resembles the school that existed in 2005. Then, the students were mostly White and few qualified for the free and reduced-price meals program; today, there is no…

Blepharophimosis, ptosis, polythelia and brachydactyly (BPPB): a new autosomal dominant syndrome?

PubMed

Wittebol-Post, D; Hennekam, R C

1993-10-01

A father and two sons with blepharophimosis, ptosis, polythelia and brachydactyly are presented, apparently without other abnormalities. The features do not fit into any previously described syndrome. This condition may represent a hitherto undescribed syndrome, although resemblance with the blepharophimosis-ptosis-epicanthus inversus syndrome exists. Inheritance is probably autosomal dominant.

Reason, Education, and Liberalism: Family Resemblance within an Overlapping Consensus.

ERIC Educational Resources Information Center

Halliday, John

2001-01-01

Discusses recent debates concerning the nature of liberalism and its central feature of reason. Examines ideas from Jonathan, Hirst, Rawls, Gadamer, Wittgenstein, Taylor, and Ackerman. Suggests that the search for transcendental conceptions of justice and reason must be abandoned in favor of a more fluid curriculum structure. (Contains 18…

The Growth and Decay of Equatorial Backscatter Plumes.

DTIC Science & Technology

1980-02-01

spatially connected to bottomside backscatter, a feature noted in Jica- marca radar observations that led Woodman and La Hoz (1976) to speculate that...described in Section Ill-B, this pattern of plume growth resembles the "C-shaped" and "fishtail" patterns found in Jica- marca radar RTI displays of 50-MHz

Integrated genomic characterization of oesophageal carcinoma.

PubMed

2017-01-12

Oesophageal cancers are prominent worldwide; however, there are few targeted therapies and survival rates for these cancers remain dismal. Here we performed a comprehensive molecular analysis of 164 carcinomas of the oesophagus derived from Western and Eastern populations. Beyond known histopathological and epidemiologic distinctions, molecular features differentiated oesophageal squamous cell carcinomas from oesophageal adenocarcinomas. Oesophageal squamous cell carcinomas resembled squamous carcinomas of other organs more than they did oesophageal adenocarcinomas. Our analyses identified three molecular subclasses of oesophageal squamous cell carcinomas, but none showed evidence for an aetiological role of human papillomavirus. Squamous cell carcinomas showed frequent genomic amplifications of CCND1 and SOX2 and/or TP63, whereas ERBB2, VEGFA and GATA4 and GATA6 were more commonly amplified in adenocarcinomas. Oesophageal adenocarcinomas strongly resembled the chromosomally unstable variant of gastric adenocarcinoma, suggesting that these cancers could be considered a single disease entity. However, some molecular features, including DNA hypermethylation, occurred disproportionally in oesophageal adenocarcinomas. These data provide a framework to facilitate more rational categorization of these tumours and a foundation for new therapies.

Photoelectric charging of partially sunlit dielectric surfaces in space

NASA Technical Reports Server (NTRS)

De, B. R.; Criswell, D. R.

1977-01-01

Sunlight-shadow effects may substantially alter the charging situation for a dielectric surface. The sunlight-shadow boundary tends to be the site of intense multipole electric fields. Charges on a sunlit dielectric surface have a finite effective mobility. The charge distribution tends to resemble that on a conducting surface. A boundary between a conducting and a dielectric surface may not represent a conductivity discontinuity when this boundary is sunlit; charges may migrate at a nontrivial rate across the boundary. A contracting or expanding sunlit area may experience a supercharging.

Non-uniform Erosion and Surface Evolution of Plasma-Facing Materials for Electric Propulsion

NASA Astrophysics Data System (ADS)

Matthes, Christopher Stanley Rutter

A study regarding the surface evolution of plasma-facing materials is presented. Experimental efforts were performed in the UCLA Pi Facility, designed to explore the physics of plasma-surface interactions. The influence of micro-architectured surfaces on the effects of plasma sputtering is compared with the response of planar samples. Ballistic deposition of sputtered atoms as a result of geometric re-trapping is observed. This provides a self-healing mechanism of micro-architectured surfaces during plasma exposure. This result is quantified using a QCM to demonstrate the evolution of surface features and the corresponding influence on the instantaneous sputtering yield. The sputtering yield of textured molybdenum samples exposed to 300 eV Ar plasma is found to be roughly 1 of the 2 corresponding value of flat samples, and increases with ion fluence. Mo samples exhibited a sputtering yield initially as low as 0.22+/-8%, converging to 0.4+/-8% at high fluence. Although the yield is dependent on the initial surface structure, it is shown to be transient, reaching a steady-state value that is independent of initial surface conditions. A continuum model of surface evolution resulting from sputtering, deposition and surface diffusion is also derived to resemble the damped Kuramoto-Sivashinsky (KS) equation of non-linear dynamics. Linear stability analysis of the evolution equation provides an estimate of the selected wavelength, and its dependence on the ion energy and angle of incidence. The analytical results are confirmed by numerical simulations of the equation with a Fast Fourier Transform method. It is shown that for an initially flat surface, small perturbations lead to the evolution of a selected surface pattern that has nano- scale wavelength. When the surface is initially patterned by other means, the final resulting pattern is a competition between the "templated" pattern and the "self-organized" structure. Potential future routes of research are also discussed, corresponding to a design analysis of the current experimental study.

Identification of the emission features near 3.5 microns in the pre main sequence star HD 97048

NASA Technical Reports Server (NTRS)

Baas, F.; Allamandola, L. J.; Geballe, T. R.; Persson, S. E.; Lacy, J. H.

1982-01-01

The spectrum of HD97048 was measured with a resolving power of 450 between 3.37 and 3.64 microns. The prominent feature near 3.5 microns is well resolved, with a peak at 3.53 microns and a wing extending to a shorter wavelength. The weaker feature near 3.4 microns is found to peak at 3.43 microns, in contrast to the 3.40 micron feature seen in other astronomical objects. The observed spectrum strongly resembles laboratory spectra of mixtures of monomeric and dimeric formaldehyde embedded in low temperature solids. Of various possible excitation mechanisms, ultraviolet pumped infrared fluorescence of formaldehyde in interstellar grains provides the best explanation for the observed spectrum of HD 97048.

Morphology Tuning of Strontium Tungstate Nanoparticles

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

Joseph, S.; George, T.; George, K. C.

2007-08-22

Strontium tungstate nanocrystals in two different morphologies are successfully synthesized by controlled precipitation in aqueous and in poly vinyl alcohol (PVA) medium. Structural characterizations are carried out by XRD and SEM. The average particle size calculated for the SrWO4 prepared in the two different solvents ranges 20-24 nm. The SEM pictures show that the surface morphologies of the SrWO4 nanoparticles in aqueous medium resemble mushroom and the SrWO4 nanoparticles in PVA medium resemble cauliflower. Investigations on the room temperature luminescent properties of the strontium tungstate nanoparticles prepared in aqueous and PVA medium shows strong emissions around 425 nm.

Surface water retardation around single-chain polymeric nanoparticles: critical for catalytic function?

PubMed

Stals, Patrick J M; Cheng, Chi-Yuan; van Beek, Lotte; Wauters, Annelies C; Palmans, Anja R A; Han, Songi; Meijer, E W

2016-03-01

A library of water-soluble dynamic single-chain polymeric nanoparticles (SCPN) was prepared using a controlled radical polymerisation technique followed by the introduction of functional groups, including probes at targeted positions. The combined tools of electron paramagnetic resonance (EPR) and Overhauser dynamic nuclear polarization (ODNP) reveal that these SCPNs have structural and surface hydration properties resembling that of enzymes.

Fundamentals of capillary electrochromatography: migration behavior of ionized sample components.

PubMed

Xiang, Rong; Horváth, Csaba

2002-02-15

The mechanism of separating charged species by capillary electrochromatography (CEC) was modeled with the conditions of ideal/linear chromatography by using a simple random walk. The most novel aspect of the work rests with the assumption that in sufficiently high electric field ionized sample components can also migrate in the adsorbed state on the ionized surface of the stationary phase. This feature of CEC leads to the introduction of three dimensionless parameters: alpha, reduced mobility of a sample component with the electrosmotic mobility as the reference; beta, the CEC retention factor; and gamma, the ratio of the electrophoretic migration velocity and the velocity of surface electrodiffusion. Since the interplay of retentive and electrophoretic forces determines the overall migration velocity, the separation mechanism in CEC is governed by the relative importance of the above parameters. The model predicts conditions under which the features of the CEC system engender migration behavior that manifests itself in a relatively narrow elution window and in a gradient like elution pattern in the separation of peptides and proteins by using pro forma isocratic CEC. It is believed that such elution patterns, which resemble those obtained by the use of external gradient of the eluent, are brought about by the formation of an internal gradient in the CEC system that gave rise to concomitant peak compression. The peculiarities of CEC are discussed in the three operational modalities of the technique: co-current, countercurrent, and co-counter CEC. The results suggest that CEC, which is often called "liquid chromatography on electrophoretic platform" is an analytical tool with great potential in the separation of peptides and proteins.

Chimeric human parainfluenza virus bearing the Ebola virus glycoprotein as the sole surface protein is immunogenic and highly protective against Ebola virus challenge

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

Bukreyev, Alexander; Marzi, Andrea; Feldmann, Friederike

2009-01-20

We generated a new live-attenuated vaccine against Ebola virus (EBOV) based on a chimeric virus HPIV3/{delta}F-HN/EboGP that contains the EBOV glycoprotein (GP) as the sole transmembrane envelope protein combined with the internal proteins of human parainfluenza virus type 3 (HPIV3). Electron microscopy analysis of the virus particles showed that they have an envelope and surface spikes resembling those of EBOV and a particle size and shape resembling those of HPIV3. When HPIV3/{delta}F-HN/EboGP was inoculated via apical surface of an in vitro model of human ciliated airway epithelium, the virus was released from the apical surface; when applied to basolateral surface,more » the virus infected basolateral cells but did not spread through the tissue. Following intranasal (IN) inoculation of guinea pigs, scattered infected cells were detected in the lungs by immunohistochemistry, but infectious HPIV3/{delta}F-HN/EboGP could not be recovered from the lungs, blood, or other tissues. Despite the attenuation, the virus was highly immunogenic, and a single IN dose completely protected the animals against a highly lethal intraperitoneal challenge of guinea pig-adapted EBOV.« less

Molecular composition and surface properties of storage lipid particles in wax bean (Phaseolus vulgaris).

PubMed

Froese, Carol D; Nowack, Linda; Cholewa, Ewa; Thompson, John E

2003-03-01

Lipid particles have been isolated from seeds of wax bean (Phaseolus vulgaris), a species in which starch and protein rather than lipid are the major seed storage reserves. These lipid particles resemble oil bodies present in oil-rich seeds in that > 90% of their lipid is triacylglycerol. Moreover, this triacylglycerol is rapidly metabolized during seed germination indicating that it is a storage reserve. The phospholipid surfaces of oil bodies are known to be completely coated with oleosin which prevents their coalescence, particularly during desiccation of the developing seed. This would appear to be necessary since lipid is the major storage reserve in oil seeds, and there are very few alternate types of storage particles in the cytoplasm of oil seed endosperm to provide a buffer against coalescence of oil bodies by isolating them from one another. The present study indicates that the surfaces of lipid particles from wax bean are not completely coated with oleosin and feature regions of naked phospholipid. This finding has been interpreted as reflecting the fact that lipid particles in wax been seeds are less prone to coalescence than oil bodies of oil-rich seeds. This arises because the individual lipid particles are interspersed in situ among highly abundant protein bodies and starch grains and hence less likely to come in contact with one another, even during desiccation of the developing seed.

Convection and fluidization in oscillatory granular flows: The role of acoustic streaming.

PubMed

Valverde, Jose Manuel

2015-06-01

Convection and fluidization phenomena in vibrated granular beds have attracted a strong interest from the physics community since the last decade of the past century. As early reported by Faraday, the convective flow of large inertia particles in vibrated beds exhibits enigmatic features such as frictional weakening and the unexpected influence of the interstitial gas. At sufficiently intense vibration intensities surface patterns appear bearing a stunning resemblance with the surface ripples (Faraday waves) observed for low-viscosity liquids, which suggests that the granular bed transits into a liquid-like fluidization regime despite the large inertia of the particles. In his 1831 seminal paper, Faraday described also the development of circulation air currents in the vicinity of vibrating plates. This phenomenon (acoustic streaming) is well known in acoustics and hydrodynamics and occurs whenever energy is dissipated by viscous losses at any oscillating boundary. The main argument of the present paper is that acoustic streaming might develop on the surface of the large inertia particles in the vibrated granular bed. As a consequence, the drag force on the particles subjected to an oscillatory viscous flow is notably enhanced. Thus, acoustic streaming could play an important role in enhancing convection and fluidization of vibrated granular beds, which has been overlooked in previous studies. The same mechanism might be relevant to geological events such as fluidization of landslides and soil liquefaction by earthquakes and sound waves.

The Viking mission to Mars

NASA Technical Reports Server (NTRS)

1974-01-01

This monograph describes the National Aeronautics and Space Administration's program to explore the planet that most nearly resembles the earth and the search for life on the surface of Mars that the Vikings are scheduled to begin in 1976.

Collectivity in Small Collision Systems: An Initial-State Perspective

DOE PAGES

Schlichting, Sören; Tribedy, Prithwish

2016-01-01

Measurements of multiparticle correlations in the collisions of small systems such as p+p, p/d/ 3 He+A show striking similarity to the observations in heavy-ion collisions. A number of observables measured in the high-multiplicity events of these systems resemble features that are attributed to collectivity driven by hydrodynamics. However, alternative explanations based on initial-state dynamics are able to describe many characteristic features of these measurements. In this brief review, we highlight some of the recent developments and outstanding issues in this direction.

Selected Case From the Arkadi M. Rywlin International Pathology Slide Seminar: Benign Warthin Tumor of the Thyroid.

PubMed

Peckova, Kvetoslava; Daum, Ondrej; Michal, Michael; Curcikova, Radmila; Michal, Michal

2016-09-01

We report on an exceedingly rare lesion of the thyroid probably of a branchial cleft origin, which was not published in the world literature before. A 58-year-old woman underwent a total thyroidectomy for bilateral goiter. Grossly, there was one yellowish nodule sized 15 mm in the largest dimension found in the right lobe. Microscopically, the thyroid parenchyma showed signs of Hashimoto thyroiditis. The nodule in the right lobe was composed of a part of solid cell nests appearance, another part resembling a branchial cleft cyst, and a part resembling Warthin tumor. This lesion may belong to the histogenetically similar group of entities in the head and neck region which are derived from branchial cleft derivatives and which, under the inflammatory influence, have the ability to a cystic dilatation and proliferation of the epithelial component. The epithelium can afterwards become papillary and may undergo oncocytic transformation, thus gaining features that impart the resemblance of a Warthin tumor. Club members generally agreed with a submitted diagnosis of benign Warthin tumor of the thyroid.

Analysis of renal cancer cell lines from two major resources enables genomics-guided cell line selection

NASA Astrophysics Data System (ADS)

Sinha, Rileen; Winer, Andrew G.; Chevinsky, Michael; Jakubowski, Christopher; Chen, Ying-Bei; Dong, Yiyu; Tickoo, Satish K.; Reuter, Victor E.; Russo, Paul; Coleman, Jonathan A.; Sander, Chris; Hsieh, James J.; Hakimi, A. Ari

2017-05-01

The utility of cancer cell lines is affected by the similarity to endogenous tumour cells. Here we compare genomic data from 65 kidney-derived cell lines from the Cancer Cell Line Encyclopedia and the COSMIC Cell Lines Project to three renal cancer subtypes from The Cancer Genome Atlas: clear cell renal cell carcinoma (ccRCC, also known as kidney renal clear cell carcinoma), papillary (pRCC, also known as kidney papillary) and chromophobe (chRCC, also known as kidney chromophobe) renal cell carcinoma. Clustering copy number alterations shows that most cell lines resemble ccRCC, a few (including some often used as models of ccRCC) resemble pRCC, and none resemble chRCC. Human ccRCC tumours clustering with cell lines display clinical and genomic features of more aggressive disease, suggesting that cell lines best represent aggressive tumours. We stratify mutations and copy number alterations for important kidney cancer genes by the consistency between databases, and classify cell lines into established gene expression-based indolent and aggressive subtypes. Our results could aid investigators in analysing appropriate renal cancer cell lines.

Opal-like Multicolor Appearance of Self-Assembled Photonic Array.

PubMed

Arnon, Zohar A; Pinotsi, Dorothea; Schmidt, Matthias; Gilead, Sharon; Guterman, Tom; Sadhanala, Aditya; Ahmad, Shahab; Levin, Aviad; Walther, Paul; Kaminski, Clemens F; Fändrich, Marcus; Kaminski Schierle, Gabriele S; Adler-Abramovich, Lihi; Shimon, Linda J W; Gazit, Ehud

2018-06-20

Molecular self-assembly of short peptide building blocks leads to the formation of various material architectures that may possess unique physical properties. Recent studies had confirmed the key role of biaromaticity in peptide self-assembly, with the diphenylalanine (FF) structural family as an archetypal model. Another significant direction in the molecular engineering of peptide building blocks is the use of fluorenylmethoxycarbonyl (Fmoc) modification, which promotes the assembly process and may result in nanostructures with distinctive features and macroscopic hydrogel with supramolecular features and nanoscale order. Here, we explored the self-assembly of the protected, noncoded fluorenylmethoxycarbonyl-β,β-diphenyl-Ala-OH (Fmoc-Dip) amino acid. This process results in the formation of elongated needle-like crystals with notable aromatic continuity. By altering the assembly conditions, arrays of spherical particles were formed that exhibit strong light scattering. These arrays display vivid coloration, strongly resembling the appearance of opal gemstones. However, unlike the Rayleigh scattering effect produced by the arrangement of opal, the described optical phenomenon is attributed to Mie scattering. Moreover, by controlling the solution evaporation rate, i.e., the assembly kinetics, we were able to manipulate the resulting coloration. This work demonstrates a bottom-up approach, utilizing self-assembly of a protected amino acid minimal building block, to create arrays of organic, light-scattering colorful surfaces.

Metastatic colonic and gastric polyps from breast cancer resembling hyperplastic polyps.

PubMed

Horimoto, Yoshiya; Hirashima, Tetsuro; Arakawa, Atsushi; Miura, Hiroyoshi; Saito, Mitsue

2018-03-23

Breast cancer metastasis to the gastrointestinal tract is relatively rare and is generally found when patients complain of symptoms such as gastrointestinal obstruction. Herein, we report a case with metastatic colonic and gastric lesions from breast cancer, with the formation of mucosal polyps which resembled typical hyperplastic polyps.A 47-year-old woman underwent curable surgery for breast cancer and received standard systemic treatments. Her primary tumor was composed of a mix of invasive lobular and ductal carcinomas. During adjuvant endocrine therapy, she developed multiple colonic metastases, identified by colonoscopy performed as part of a general health check-up. She had no symptoms. Small elevated sessile polyps in the transverse colon and rectum showed histological features of signet-ring cell type adenocarcinoma, similar to the invasive lobular component of the primary breast cancer. During treatments for recurrent disease, she also developed multiple gastric metastases, with the same endoscopic and pathological features as the colonic lesions. Her treatment regimen was switched to oral chemotherapy, and she has since maintained stable disease for nearly 3 years. Multiple bone metastases eventually developed, and she was again switched to another systemic treatment but, to date, has remained free of symptoms.We emphasize that the endoscopic findings of the metastatic lesions in the colon and stomach in this case highly resembled hyperplastic polyps. Since biopsy is not always performed for hyperplastic polyps in the gastrointestinal tract, we believe that this case report may encourage endoscopists to offer biopsies to the patient who has a history of breast cancer.

Structure of Bombyx mori densovirus 1, a silkworm pathogen.

PubMed

Kaufmann, Bärbel; El-Far, Mohamed; Plevka, Pavel; Bowman, Valorie D; Li, Yi; Tijssen, Peter; Rossmann, Michael G

2011-05-01

Bombyx mori densovirus 1 (BmDNV-1), a major pathogen of silkworms, causes significant losses to the silk industry. The structure of the recombinant BmDNV-1 virus-like particle has been determined at 3.1-Å resolution using X-ray crystallography. It is the first near-atomic-resolution structure of a virus-like particle within the genus Iteravirus. The particles consist of 60 copies of the 55-kDa VP3 coat protein. The capsid protein has a β-barrel "jelly roll" fold similar to that found in many diverse icosahedral viruses, including archaeal, bacterial, plant, and animal viruses, as well as other parvoviruses. Most of the surface loops have little structural resemblance to other known parvovirus capsid proteins. In contrast to vertebrate parvoviruses, the N-terminal β-strand of BmDNV-1 VP3 is positioned relative to the neighboring 2-fold related subunit in a "domain-swapped" conformation, similar to findings for other invertebrate parvoviruses, suggesting domain swapping is an evolutionarily conserved structural feature of the Densovirinae.

Quantized transport and steady states of Floquet topological insulators

NASA Astrophysics Data System (ADS)

Esin, Iliya; Rudner, Mark S.; Refael, Gil; Lindner, Netanel H.

2018-06-01

Robust electronic edge or surface modes play key roles in the fascinating quantized responses exhibited by topological materials. Even in trivial materials, topological bands and edge states can be induced dynamically by a time-periodic drive. Such Floquet topological insulators (FTIs) inherently exist out of equilibrium; the extent to which they can host quantized transport, which depends on the steady-state population of their dynamically induced edge states, remains a crucial question. In this work, we obtain the steady states of two-dimensional FTIs in the presence of the natural dissipation mechanisms present in solid state systems. We give conditions under which the steady-state distribution resembles that of a topological insulator in the Floquet basis. In this state, the distribution in the Floquet edge modes exhibits a sharp feature akin to a Fermi level, while the bulk hosts a small density of excitations. We determine the regimes where topological edge-state transport persists and can be observed in FTIs.

Osteomyelitis caused by Neosartorya pseudofischeri.

PubMed Central

Padhye, A A; Godfrey, J H; Chandler, F W; Peterson, S W

1994-01-01

The first case of osteomyelitis caused by Neosartorya pseudofischeri is reported. The patient, a 77-year-old male with a history of silicosis and tuberculosis, on X-ray examination revealed lytic lesions of L2 and L3 vertebrae suspicious for metastatic lesions. Histologic examination of biopsy specimens from vertebral bodies showed short, distorted, extra- and intracellular, hyaline hyphal fragments. The culture from the biopsy tissue produced numerous, evanescent asci containing eight ellipsoidal ascospores with two distinctive equatorial bands ca. 1 micron wide. When examined by a scanning electron microscope, ascospores exhibited a convex surface ornamented with raised flaps of tissue, in shape resembling triangular projections or long ridge lines. The conidial state (anamorph) was identified as Aspergillus thermomutatus on the basis of conidial columns which were smaller and less tightly packed as well as of a lighter shade of green than those observed in Aspergillus fumigatus. On the basis of the morphologic features of the ascospores, the teleomorph was identified as N. pseudofischeri. Images PMID:7852580

Phase separation in artificial vesicles driven by light and curvature

NASA Astrophysics Data System (ADS)

Rinaldin, Melissa; Pomp, Wim; Schmidt, Thomas; Giomi, Luca; Kraft, Daniela; Physics of Life Processes Team; Soft; Bio Mechanics Collaboration; Self-Assembly in Soft Matter Systems Collaboration

The role of phase-demixing in living cells, leading to the lipid-raft hypothesis, has been extensively studied. Lipid domains of higher lipid chain order are proposed to regulate protein spatial organization. Giant Unilamellar Vesicles provide an artificial model to study phase separation. So far temperature was used to initiate the process. Here we introduce a new methodology based on the induction of phase separation by light. To this aim, the composition of the lipid membrane is varied by photo-oxidation of lipids. The control of the process gained by using light allowed us to observe vesicle shape fluctuations during phase-demixing. The presence of fluctuations near the critical mixing point resembles features of a critical process. We quantitatively analyze these fluctuations using a 2d elastic model, from which we can estimate the material parameters such as bending rigidity and surface tension, demonstrating the non-equilibrium critical behaviour. Finally, I will describe recent attempts toward tuning the membrane composition by controlling the vesicle curvature.

Problems arising in the diagnosis of primary ovarian transitional cell carcinoma after the occurrence of a transitional cell carcinoma of the bladder: a report of a difficult case and a critical review of literature.

PubMed

Raspollini, Maria Rosaria; Paglierani, Milena; Taddei, Gian Luigi

2009-03-01

Transitional cell carcinoma (TCC) of the ovary is a recently recognized subtype of ovarian surface epithelial-stromal cancer that morphologically resembles a TCC of the bladder. The most frequent metastases to ovaries come from the gastrointestinal tract and from breast carcinoma, but metastatic TCCs from the urinary tract to the ovary have been reported. TCC of the bladder is the sixth most common cancer in European and North American countries and its incidence has been increasing. We recently observed a woman, who previously had undergone endoscopic resection of a TCC of the bladder. She was affected by an ovarian bilateral tumor with features of malignant transitional cell tumor, characterized by papillae with multilayered transitional epithelium infiltrating the ovarian stroma. In this study, we showed the utility of WT1 and a panel of immunohistochemical markers in the difficult differential diagnosis between bladder and ovarian TCC.

Tuning the Fermi velocity in Dirac materials with an electric field.

PubMed

Díaz-Fernández, A; Chico, Leonor; González, J W; Domínguez-Adame, F

2017-08-14

Dirac materials are characterized by energy-momentum relations that resemble those of relativistic massless particles. Commonly denominated Dirac cones, these dispersion relations are considered to be their essential feature. These materials comprise quite diverse examples, such as graphene and topological insulators. Band-engineering techniques should aim to a full control of the parameter that characterizes the Dirac cones: the Fermi velocity. We propose a general mechanism that enables the fine-tuning of the Fermi velocity in Dirac materials in a readily accessible way for experiments. By embedding the sample in a uniform electric field, the Fermi velocity is substantially modified. We first prove this result analytically, for the surface states of a topological insulator/semiconductor interface, and postulate its universality in other Dirac materials. Then we check its correctness in carbon-based Dirac materials, namely graphene nanoribbons and nanotubes, thus showing the validity of our hypothesis in different Dirac systems by means of continuum, tight-binding and ab-initio calculations.

Scaling mimesis: Morphometric and ecomorphological similarities in three sympatric plant-mimetic fish of the family Carangidae (Teleostei)

PubMed Central

de Queiroz, Alexya Cunha; Vallinoto, Marcelo; Sakai, Yoichi; Giarrizzo, Tommaso

2018-01-01

The mimetic juveniles of a number of carangid fish species resemble plant parts floating near the water surface, such as leaves, seeds and other plant debris. The present study is the first to verify the morphological similarities and ecomorphological relationships between three carangids (Oligoplites saurus, Oligoplites palometa and Trachinotus falcatus) and their associated plant models. Behavioral observations were conducted in the estuary of Curuçá River, in northeastern Pará (Brazil) between August 2015 and July 2016. Individual fishes and associated floating objects (models) were sampled for comparative analysis using both geometric and morphometric approaches. While the mimetic fish and their models retain their own distinct, intrinsic morphological features, a high degree of morphological similarity was found between each fish species and its model. The morphometric analyses revealed a general tendency of isometric development in all three fish species, probably related to their pelagic habitats, during all ontogenetic stages. PMID:29558476

A structural basis for antigen recognition by the T cell-like lymphocytes of sea lamprey

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

Deng, Lu; Velikovsky, C. Alejandro; Xu, Gang

Adaptive immunity in jawless vertebrates is mediated by leucine-rich repeat proteins called 'variable lymphocyte receptors' (VLRs). Two types of VLR (A and B) are expressed by mutually exclusive lymphocyte populations in lamprey. VLRB lymphocytes resemble the B cells of jawed vertebrates; VLRA lymphocytes are similar to T cells. We determined the structure of a high-affinity VLRA isolated from lamprey immunized with hen egg white lysozyme (HEL) in unbound and antigen-bound forms. The VLRA-HEL complex demonstrates that certain VLRAs, like {gamma}{delta} T-cell receptors (TCRs) but unlike {alpha}{beta} TCRs, can recognize antigens directly, without a requirement for processing or antigen-presenting molecules. Thus,more » these VLRAs feature the nanomolar affinities of antibodies, the direct recognition of unprocessed antigens of both antibodies and {gamma}{delta} TCRs, and the exclusive expression on the lymphocyte surface that is unique to {alpha}{beta} and {gamma}{delta} TCRs.« less

Semiconductor Nanomembrane Tubes: Three-Dimensional Confinement for Controlled Neurite Outgrowth

PubMed Central

Yu, Minrui; Huang, Yu; Ballweg, Jason; Shin, Hyuncheol; Huang, Minghuang; Savage, Donald E.; Lagally, Max G.; Dent, Erik W.; Blick, Robert H.; Williams, Justin C.

2013-01-01

In many neural culture studies, neurite migration on a flat, open surface does not reflect the three-dimensional (3D) microenvironment in vivo. With that in mind, we fabricated arrays of semiconductor tubes using strained silicon (Si) and germanium (Ge) nanomembranes and employed them as a cell culture substrate for primary cortical neurons. Our experiments show that the SiGe substrate and the tube fabrication process are biologically viable for neuron cells. We also observe that neurons are attracted by the tube topography, even in the absence of adhesion factors, and can be guided to pass through the tubes during outgrowth. Coupled with selective seeding of individual neurons close to the tube opening, growth within a tube can be limited to a single axon. Furthermore, the tube feature resembles the natural myelin, both physically and electrically, and it is possible to control the tube diameter to be close to that of an axon, providing a confined 3D contact with the axon membrane and potentially insulating it from the extracellular solution. PMID:21366271

Automatic Generation of Caricatures with Multiple Expressions Using Transformative Approach

NASA Astrophysics Data System (ADS)

Liao, Wen-Hung; Lai, Chien-An

The proliferation of digital cameras has changed the way we create and share photos. Novel forms of photo composition and reproduction have surfaced in recent years. In this paper, we present an automatic caricature generation system using transformative approaches. By combing facial feature detection, image segmentation and image warping/morphing techniques, the system is able to generate stylized caricature using only one reference image. When more than one reference sample are available, the system can either choose the best fit based on shape matching, or synthesize a composite style using polymorph technique. The system can also produce multiple expressions by controlling a subset of MPEG-4 facial animation parameters (FAP). Finally, to enable flexible manipulation of the synthetic caricature, we also investigate issues such as color quantization and raster-to-vector conversion. A major strength of our method is that the synthesized caricature bears a higher degree of resemblance to the real person than traditional component-based approaches.

Geologic map of the Artemis Chasma quadrangle (V-48), Venus

USGS Publications Warehouse

Bannister, Roger A.; Hansen, Vicki L.

2010-01-01

Artemis, named for the Greek goddess of the hunt, represents an approximately 2,600 km diameter circular feature on Venus, and it may represent the largest circular structure in our solar system. Artemis, which lies between the rugged highlands of Aphrodite Terra to the north and relatively smooth lowlands to the south, includes an interior topographic high surrounded by the 2,100-km-diameter, 25- to 200-km-wide, 1- to 2-km-deep circular trough, called Artemis Chasma, and an outer rise that grades outward into the surrounding lowland. Although several other chasmata exist in the area and globally, other chasmata have generally linear trends that lack the distinctive circular pattern of Artemis Chasma. The enigmatic nature of Artemis has perplexed researchers since Artemis Chasma was first identified in Pioneer Venus data. Although Venus' surface abounds with circular to quasi-circular features at a variety of scales, including from smallest to largest diameter features: small shield edifices (>1 km), large volcanic edifices (100-1,000 km), impact craters (1-270 km), coronae (60-1,010 km), volcanic rises and crustal plateaus (~1,500-2,500 km), Artemis defies classification into any of these groups. Artemis dwarfs Venus' largest impact crater, Mead (~280 km diameter); Artemis also lacks the basin topography, multiple ring structures, and central peak expected for large impact basins. Topographically, Artemis resembles some Venusian coronae; however Artemis is an order of magnitude larger than the average corona (200 km) and about twice the size of Heng-O Corona (which is 1,010 km in diameter), the largest of Venusian coronae. In map view Artemis' size and shape resemble volcanic rises and crustal plateaus; however, both of these classes of features differ topographically from Artemis. Volcanic rises and crustal plateaus form broad domical regions, and steep-sided regions with flat tops, respectively; furthermore, neither rises nor plateaus include circular troughs. So although it seems clear what Artemis is not, there is little consensus about what Artemis is, much less how Artemis formed. Debate during the past decade has resulted in the proposal of at least four hypotheses for Artemis' formation. The first (herein referred to as H1) is that Artemis Chasma represents a zone of northwest-directed convergence and subduction. The second hypothesis (herein referred to as H2) is that Artemis consists of a composite structure with a part of its interior region marking the exposure of deformed ductile deep-crustal rocks analogous to a terrestrial metamorphic core complex. The third (herein referred to as H3) is that Artemis reflects the surface expression of an ancient (>3.5 Ga) huge bolide impact event on cold strong lithosphere. The fourth hypothesis (herein referred to as H4) is that Artemis marks the surface expression of a deep mantle plume. Each of these hypotheses holds different implications for Venus geodynamics and evolution processes, and for terrestrial planet processes in general. Viability of H1 would provide support that terrestrial-like plate-tectonic processes once occurred on Earth's sister planet. The feasibility of H2 would require high values of crustal extension and therefore imply that significant horizontal displacements occurred on Venus-displacement that may or may not be related to terrestrial-like plate-tectonic processes. The possibility of H3 would suggest that Venus' surface is extremely old, and that Venus has experienced very little dynamic activity for the last 3.5 billion years or more; this would further imply that Venus is essentially tectonically dead, and has been for most of its history. This view contrasts strongly with studies that highlight a rich history of Venus including activity at least as young as 750 million years ago, and quite likely up to the present. If H4 has credibility, then Artemis could provide clues to cooling mechanisms of Earth's sister planet. Each of these hypotheses

Odontogenic keratocyst: a peripheral variant.

PubMed

Vij, H; Vij, R; Gupta, V; Sengupta, S

2011-01-01

Odontogenic keratocyst, which is developmental in nature, is an intraosseous lesion though on rare occasions it may occur in an extraosseous location. The extraosseous variant is referred to as peripheral odontogenic keratocyst. Though, clinically, peripheral odontogenic keratocyst resembles the gingival cyst of adults, it has histologic features that are pathognomonic of odontogenic keratocyst. This article presents a case of this uncommon entity.

Building Robota, a Mini-Humanoid Robot for the Rehabilitation of Children with Autism

ERIC Educational Resources Information Center

Billard, Aude; Robins, Ben; Nadel, Jacqueline; Dautenhahn, Kerstin

2007-01-01

The Robota project constructs a series of multiple-degrees-of-freedom, doll-shaped humanoid robots, whose physical features resemble those of a human baby. The Robota robots have been applied as assistive technologies in behavioral studies with low-functioning children with autism. These studies investigate the potential of using an imitator robot…

Users' Perceptions of the Web As Revealed by Transaction Log Analysis.

ERIC Educational Resources Information Center

Moukdad, Haidar; Large, Andrew

2001-01-01

Describes the results of a transaction log analysis of a Web search engine, WebCrawler, to analyze user's queries for information retrieval. Results suggest most users do not employ advanced search features, and the linguistic structure often resembles a human-human communication model that is not always successful in human-computer communication.…

AlxGa1-xAs Single-Quantum-Well Surface-Emitting Lasers

NASA Technical Reports Server (NTRS)

Kim, Jae H.

1992-01-01

Surface-emitting solid-state laser contains edge-emitting Al0.08Ga0.92As single-quantum-well (SQW) active layer sandwiched between graded-index-of-refraction separate-confinement-heterostructure (GRINSCH) layers of AlxGa1-xAs, includes etched 90 degree mirrors and 45 degree facets to direct edge-emitted beam perpendicular to top surface. Laser resembles those described in "Pseudomorphic-InxGa1-xAs Surface-Emitting Lasers" (NPO-18243). Suitable for incorporation into optoelectronic integrated circuits for photonic computing; e.g., optoelectronic neural networks.

Ranging through Gabor logons-a consistent, hierarchical approach.

PubMed

Chang, C; Chatterjee, S

1993-01-01

In this work, the correspondence problem in stereo vision is handled by matching two sets of dense feature vectors. Inspired by biological evidence, these feature vectors are generated by a correlation between a bank of Gabor sensors and the intensity image. The sensors consist of two-dimensional Gabor filters at various scales (spatial frequencies) and orientations, which bear close resemblance to the receptive field profiles of simple V1 cells in visual cortex. A hierarchical, stochastic relaxation method is then used to obtain the dense stereo disparities. Unlike traditional hierarchical methods for stereo, feature based hierarchical processing yields consistent disparities. To avoid false matchings due to static occlusion, a dual matching, based on the imaging geometry, is used.

Clinical Usefulness of Aripiprazole and Lamotrigine in Schizoaffective Presentation of Tuberous Sclerosis.

PubMed

Lee, Seung-Yup; Min, Jung-Ah; Lee, In Goo; Kim, Jung Jin

2016-08-31

Tuberous sclerosis is not as rare as once thought and has high psychiatric comorbidities. However, bipolar or psychotic features associated with tuberous sclerosis have been rarely reported. This report first presents a tuberous sclerosis patient, resembling a schizoaffective disorder of bipolar type. A patient with known tuberous sclerosis displayed mood fluctuation and psychotic features. Her symptoms did not remit along with several psychiatric medications. After hospitalization, the patient responded well with lamotrigine and aripiprazole without exacerbation. As demonstrated in this case, tuberous sclerosis may also encompass bipolar affective or psychotic features. We would like to point out the necessity to consider bipolarity in evaluating and treating tuberous sclerosis.

Pygmoid Australomelanesian Homo sapiens skeletal remains from Liang Bua, Flores: population affinities and pathological abnormalities.

PubMed

Jacob, T; Indriati, E; Soejono, R P; Hsü, K; Frayer, D W; Eckhardt, R B; Kuperavage, A J; Thorne, A; Henneberg, M

2006-09-05

Liang Bua 1 (LB1) exhibits marked craniofacial and postcranial asymmetries and other indicators of abnormal growth and development. Anomalies aside, 140 cranial features place LB1 within modern human ranges of variation, resembling Australomelanesian populations. Mandibular and dental features of LB1 and LB6/1 either show no substantial deviation from modern Homo sapiens or share features (receding chins and rotated premolars) with Rampasasa pygmies now living near Liang Bua Cave. We propose that LB1 is drawn from an earlier pygmy H. sapiens population but individually shows signs of a developmental abnormality, including microcephaly. Additional mandibular and postcranial remains from the site share small body size but not microcephaly.

Modern fire regime resembles historical fire regime in a ponderosa pine forest on Native American land

Treesearch

Amanda B. Stan; Peter Z. Fule; Kathryn B. Ireland; Jamie S. Sanderlin

2014-01-01

Forests on tribal lands in the western United States have seen the return of low-intensity surface fires for several decades longer than forests on non-tribal lands. We examined the surface fire regime in a ponderosa pinedominated (Pinus ponderosa) forest on the Hualapai tribal lands in the south-western United States. Using fire-scarred trees, we inferred temporal (...

Multi-Scale Fractal Analysis of Image Texture and Pattern

NASA Technical Reports Server (NTRS)

Emerson, Charles W.

1998-01-01

Fractals embody important ideas of self-similarity, in which the spatial behavior or appearance of a system is largely independent of scale. Self-similarity is defined as a property of curves or surfaces where each part is indistinguishable from the whole, or where the form of the curve or surface is invariant with respect to scale. An ideal fractal (or monofractal) curve or surface has a constant dimension over all scales, although it may not be an integer value. This is in contrast to Euclidean or topological dimensions, where discrete one, two, and three dimensions describe curves, planes, and volumes. Theoretically, if the digital numbers of a remotely sensed image resemble an ideal fractal surface, then due to the self-similarity property, the fractal dimension of the image will not vary with scale and resolution. However, most geographical phenomena are not strictly self-similar at all scales, but they can often be modeled by a stochastic fractal in which the scaling and self-similarity properties of the fractal have inexact patterns that can be described by statistics. Stochastic fractal sets relax the monofractal self-similarity assumption and measure many scales and resolutions in order to represent the varying form of a phenomenon as a function of local variables across space. In image interpretation, pattern is defined as the overall spatial form of related features, and the repetition of certain forms is a characteristic pattern found in many cultural objects and some natural features. Texture is the visual impression of coarseness or smoothness caused by the variability or uniformity of image tone or color. A potential use of fractals concerns the analysis of image texture. In these situations it is commonly observed that the degree of roughness or inexactness in an image or surface is a function of scale and not of experimental technique. The fractal dimension of remote sensing data could yield quantitative insight on the spatial complexity and information content contained within these data. A software package known as the Image Characterization and Modeling System (ICAMS) was used to explore how fractal dimension is related to surface texture and pattern. The ICAMS software was verified using simulated images of ideal fractal surfaces with specified dimensions. The fractal dimension for areas of homogeneous land cover in the vicinity of Huntsville, Alabama was measured to investigate the relationship between texture and resolution for different land covers.

An Investigation into the Mechanics of Windblown Dust Entrainment from Nickel Slag Surfaces Resembling Armoured Desert Pavements

NASA Astrophysics Data System (ADS)

Sanderson, Robert Steven

The purpose of this thesis is to investigate the dynamics of PM 10 emission from a nickel slag stockpile that closely resembles a desert pavement in physical characteristics. In the field, it was observed that slag surfaces develop by natural processes into a well-armoured surface over some period of time. The surface then consists of two distinct layers; a surficial armour layer containing only non-erodible gravel and cobble-sized clasts, and an underlying dust-laden layer, which contains a wide size range of slag particles, from clay-sized to cobble-sized. This surficial armour layer protects the underlying fines from wind entrainment, at least under typical wind conditions; however, particle emissions still do occur under high wind speeds. The dynamics of particle entrainment from within these surfaces are investigated herein. It is shown that the dynamics of the boundary layer flow over these lag surfaces are influenced by the inherent roughness and permeability of the surficial armour layer, such that the flow resembles those observed over and within vegetation canopies, and those associated with permeable gravel-bed river channels. Restriction of air flow within the permeable surface produces a high-pressure zone within the pore spaces, resulting in a Kelvin-Helmholtz shear instability, which triggers coherent motions in the form of repeating burst-sweep cycles. Using Laser Doppler Anemometry (LDA), it is demonstrated that the lower boundary layer is characterized by both Q4 sweeping motions and Q2 bursting motions, while the upper boundary layer is dominated by Q2 bursts. Pore air motions within the slag material were measured using buried pressure ports. It is shown that the mean pressure gradient which forms within the slag material results in net upward displacement of air, or wind pumping. However, this net upward motion is a result of rapid oscillatory motions which are directly driven by coherent boundary layer motions. It is also demonstrated that these coherent motions are able to penetrate at least 4 cm through the surficial armour layer, thereby transporting turbulent kinetic energy (TKE) downward to the dust-laden sub-surface layer. This represents a mechanism of momentum transfer that is able to reach the erodible material, while the wind pumping effect represents a mechanism for particle exhaustion.

Multicentric squamous cell carcinona in a paca (Agouti paca) resembling Bowen's disease.

PubMed

Luppi, Marcela M; Malta, Marcelo C C; Costa, Maria E L T; Motta, Rafael O C; Santos, Renato L

2008-06-01

An 8-yr-old female paca (Agouti paca) was admitted at the Veterinary Hospital of the Belo Horizonte Zoo (Brazil) with an ulcerated cutaneous nodule of approximately 1.5 cm in diameter in the left ear. One week later, other cutaneous nodules were detected in various body locations. The animal died during a surgical procedure to remove the tumors. All cutaneous nodules were histologically similar with features of squamous cell carcinoma. Considering the predominant in situ nature of the lesion as well as its multicentric localization, the disease reported here closely resembles Bowen's disease, which has been described in humans and which has been identified as a rare neoplastic disease of cats, with one single report in a dog. This is the first report of a neoplastic disease in Agouti

Application of Fe-Ti oxide dissolution experiments to the petrogenesis of the Ekati Diamond Mine kimberlites, Northwest Territories, Canada

NASA Astrophysics Data System (ADS)

Kressall, R.; Fedortchouk, Y.; McCammon, C. A.

2015-12-01

Composition of kimberlites is ambiguous due to assimilation and fractional crystallization. We propose that the evolution history of minerals can be used to decipher the magmatic history of kimberlites. We use Fe-Ti oxides (chromite and ilmenite) from six kimberlites from the Ekati Diamond Mine and dissolution experiments to elucidate the petrogenesis of kimberlites. Experiments at 0.1 MPa and variable ƒO2s in a diopside-anorthite melt show that the dissolution rate of ilmenite is highly sensitive to ƒO2. No significant difference was observed in chromite. Zoning in chromite is related to the Fe-content and oxidation state of the melt. Experiments at 1 GPa explore the development of chromite surface resorption features in the system Ca-Mg-Si-H-C-O. Five kimberlites contain a low abundance of ilmenite, owing to a relatively high ƒO2, though ilmenite constituted 65% of oxide macocrysts in one kimberlite. Chromite compositions evolve from Mg-chromite to magnesio-ulvöspinel-magnetite (MUM) in all but one kimberlite where chromite evolves to a pleonaste composition perhaps as a result of rapid emplacement. The high abundance of MUM spinel and low abundance of ilmenite in the matrix could be related to the change in the stable Ti-phase with increasing ƒO2. Core compositions of macrocrysts vary for different mantle sources but rims converge to a composition slightly more oxidized and Mg-rich than chromite from depleted peridotite. Ilmenite commonly has rims composed of perovskite, titanite and MUM. We suggest a model where the kimberlite melt composition is controlled by the co-dissolution and co-precipitation of silicates (predominantly orthopyroxene and olivine) to explain chromite evolution in kimberlites. Resorption-related surface features on chromite macrocrysts show trigon protrusions-depressions on {111} faces and step-like features along the crystal edges resembling products of experiments in H2O fluid. We propose predominantly H2O magmatic fluid in Ekati kimberlites.

β-SiH-containing tris(silazido) rare-earth complexes as homogeneous and grafted single-site catalyst precursors for hydroamination

DOE PAGES

Eedugurala, Naresh; Wang, Zhuoran; Yan, KaKing; ...

2017-01-25

A series of homoleptic rare-earth silazido compounds and their silica-grafted derivatives were prepared to compare spectroscopic and catalytic features under homogeneous and interfacial conditions. Trivalent tris(silazido) compounds Ln{N(SiHMe 2) tBu} 3 (Ln = Sc (1), Y (2), Lu (3)) are prepared in high yield by salt metathesis reactions. Solution-phase and solid-state characterization of 1–3 by NMR and IR spectroscopy and X-ray diffraction reveals Ln←H–Si interactions. These features are retained in solvent-coordinated 2·Et 2O, 2·THF, and 3·THF. The change in spectroscopic features characterizing the secondary interactions (ν SiH, 1 J SiH) from the unactivated SiH in the silazane HN(SiHMe 2) tBumore » follows the trend 3 > 2 > 1 ≈ 2·Et 2O > 2·THF ≈ 3·THF. Ligand lability follows the same pattern, with Et 2O readily dissociating from 2·Et 2O while THF is displaced only during surface grafting reactions. 1 and 2·THF graft onto mesoporous silica nanoparticles (MSN) to give Ln{N(SiHMe 2) tBu} n@MSN (Ln = Sc (1@MSN), Y (2@MSN)) along with THF and protonated silazido as HN(SiHMe 2) tBu and H 2N tBu. The surface species are characterized by multinuclear and multidimensional solid-state (SS) NMR spectroscopic techniques, as well as diffuse reflectance FTIR, elemental analysis, and reaction stoichiometry. A key 1 J SiH SSNMR measurement reveals that the grafted sites most closely resemble Ln·THF adducts, suggesting that siloxane coordination occurs in grafted compounds. These species catalyze the hydroamination/bicyclization of aminodialkenes, and both solution-phase and interfacial conditions provide the bicyclized product with equivalent cis:trans ratios. As a result, similar diastereoselectivities mediated by catalytic sites under the two conditions suggest similar effective environments.« less

Photopolarimetric observations of the minor planet Flora.

NASA Technical Reports Server (NTRS)

Veverka, J.

1971-01-01

Review of the rotation period, phase coefficients, and polarization curve of the unusual asteroid Flora. It is an almost spherical asteroid whose period of rotation is probably 13.6 h, but may be only one half of this. Its surface layer consists of a dark material resembling lunar surface soil, but since the polarization curves of Flora and the moon, though generally similar, are not identical the surface of Flora must differ somewhat either in composition or in texture from that of the moon.

[Comparison of two powder-stream systems for tooth polishing].

PubMed

Leckel, M; Lenz, P; Gilde, H

1989-06-01

The effect of two airpolishing systems on the surface roughness of polished ceramic test pieces was compared and evaluated using standardized procedures. Test pieces resembling enamel in hardness were treated with these air-polishing systems. Using a Perthometer surface roughness was found to increase significantly. Thus the possible effects of airpolishing systems on the enamel surface should be considered. Efficiency of extrinsic stain removal was studied by SEM and documented. Photographic techniques provided information on the homogeneity of the sodium bicarbonate spray.

The Recognition without Cued Recall Phenomenon: Support for a Feature-Matching Theory over a Partial Recollection Account

ERIC Educational Resources Information Center

Ryals, Anthony J.; Cleary, Anne M.

2012-01-01

Among cues that fail to elicit successful recall, participants can still discriminate between cues that do and do not resemble studied items. This ability is referred to as recognition without cued recall (RWCR). We hypothesized that whereas recognition with cued recall is at least partly based on recalled studied information, RWCR results from a…

Loxoprofen--another NSAID associated with acute asthmatic death.

PubMed

Watanabe, T; Sakata, M; Shimabukuro, R; Sakata, K; Tabata, N; Azumi, J; Morita, M; Itaya, K

1993-01-01

Loxoprofen sodium (sodium 2[4-(2-oxocyclopentylmethyl) phenyl] dehydrate; CAS #68767-14-6) is a nonsteroidal, inflammatory drug marketed only in Japan. A case report describes its association with an acute asthmatic death with features resembling those evoked by similar drugs. The analytic methodology is reported. The blood levels of loxoprofen were in the therapeutic range. The tissue concentrations are reported.

Neuroblastoma-like schwannoma in a case of schwannomatosis: Report of a rare case

PubMed Central

Sulhyan, Kalpana R; Deshmukh, Bhakti D; Gosavi, Alka V; Ramteerthakar, Nayan A

2015-01-01

Schwannomatosis is a term used to describe patients with multiple nonvestibular schwannomas with no other stigmata of neurofibromatosis type-2 (NF2). Neuroblastoma-like schwannoma is a rare subtype of schwannoma, with histological features resembling a neuroblastoma. This case is probabaly the second case of very uncommon neuroblastoma-like schwannoma, in a patient of schwannomatosis. PMID:26715928

Neuroblastoma-like schwannoma in a case of schwannomatosis: Report of a rare case.

PubMed

Sulhyan, Kalpana R; Deshmukh, Bhakti D; Gosavi, Alka V; Ramteerthakar, Nayan A

2015-10-01

Schwannomatosis is a term used to describe patients with multiple nonvestibular schwannomas with no other stigmata of neurofibromatosis type-2 (NF2). Neuroblastoma-like schwannoma is a rare subtype of schwannoma, with histological features resembling a neuroblastoma. This case is probabaly the second case of very uncommon neuroblastoma-like schwannoma, in a patient of schwannomatosis.

Ambiguity, logic, simplicity, and dynamics: Wittgensteinian evaluative criteria in peer review of quantitative research on categorization.

PubMed

Shimp, Charles P

2004-06-30

Research on categorization has changed over time, and some of these changes resemble how Wittgenstein's views changed from his Tractatus Logico-Philosophicus to his Philosophical Investigations. Wittgenstein initially focused on unambiguous, abstract, parsimonious, logical propositions and rules, and on independent, static, "atomic facts." This approach subsequently influenced the development of logical positivism and thereby may have indirectly influenced method and theory in research on categorization: much animal research on categorization has focused on learning simple, static, logical rules unambiguously interrelating small numbers of independent features. He later rejected logical simplicity and rigor and focused instead on Gestalt ideas about figure-ground reversals and context, the ambiguity of family resemblance, and the function of details of everyday language. Contemporary contextualism has been influenced by this latter position, some features of which appear in contemporary empirical research on categorization. These developmental changes are illustrated by research on avian local and global levels of visual perceptual analysis, categorization of rectangles and moving objects, and artificial grammar learning. Implications are described for peer review of quantitative theory in which ambiguity, logical rigor, simplicity, or dynamics are designed to play important roles.

Breast cancer metastasis to the stomach resembling early gastric cancer.

PubMed

Eo, Wan Kyu

2008-12-01

Breast cancer metastases to the stomach are infrequent, with an estimated incidence rate of approximately 0.3%. Gastric metastases usually are derived from lobular rather than from ductal breast cancer. The most frequent type of a breast cancer metastasis as seen on endoscopy to the stomach is linitis plastica; features of a metastatic lesion that resemble early gastric cancer (EGC) are extremely rare. In this report, we present a case of a breast cancer metastasis to the stomach from an infiltrating ductal carcinoma (IDC) of the breast in a 48-year-old woman. The patient had undergone a left modified radical mastectomy with axillary dissection nine years prior. A gastric endoscopy performed for evaluation of nausea and anorexia showed the presence of a slightly elevated mucosal lesion in the cardia, suggestive of a type IIa EGC. A histological examination revealed nests of a carcinoma in the subepithelial lymphatics, and immunohistochemical staining for estrogen receptor was positive. This is an extremely rare case with features of type IIa EGC, but the lesion was finally identified as a cancer metastasis to the cardia of the stomach from an IDC of the breast.

The limb movement analysis of rehabilitation exercises using wearable inertial sensors.

PubMed

Bingquan Huang; Giggins, Oonagh; Kechadi, Tahar; Caulfield, Brian

2016-08-01

Due to no supervision of a therapist in home based exercise programs, inertial sensor based feedback systems which can accurately assess movement repetitions are urgently required. The synchronicity and the degrees of freedom both show that one movement might resemble another movement signal which is mixed in with another not precisely defined movement. Therefore, the data and feature selections are important for movement analysis. This paper explores the data and feature selection for the limb movement analysis of rehabilitation exercises. The results highlight that the classification accuracy is very sensitive to the mount location of the sensors. The results show that the use of 2 or 3 sensor units, the combination of acceleration and gyroscope data, and the feature sets combined by the statistical feature set with another type of feature, can significantly improve the classification accuracy rates. The results illustrate that acceleration data is more effective than gyroscope data for most of the movement analysis.

The Development of a Semtex-H Simulant for Terahertz Spectroscopy

NASA Astrophysics Data System (ADS)

Greenall, N.; Valavanis, A.; Desai, H. J.; Acheampong, D. O.; Li, L. H.; Cunningham, J. E.; Davies, A. G.; Linfield, E. H.; Burnett, A. D.

2017-03-01

The development and use of terahertz (THz) frequency spectroscopy systems for security screening has shown an increased growth over the past 15 years. In order to test these systems in real-world situations, safe simulants of illicit materials, such as Semtex-H, are required. Ideally, simulants should mimic key features of the material of interest, such that they at least resemble or even appear indistinguishable from the materials of interest to the interrogating technique(s), whilst not having hazardous or illicit properties. An ideal simulant should have similar physical properties (malleability, density, surface energy and volatility to the material of interest); be non-toxic and easy to clean and decontaminate from surfaces; be recyclable or disposable; and be useable in a public environment. Here, we present a method for developing such an explosive simulant (for Semtex-H) based on a database of THz spectra of common organic molecules, and the use of a genetic algorithm to select a mixture of compounds automatically to form such a simulant. Whilst we focus on a security application, this work could be applied to various other contexts, where the material of interest is dangerous, impractical or costly. We propose four mixtures that could then be used to test the spectral response of any instrument, working at terahertz frequencies, without the need for an explosive substance.

Quantification of biofilm structures by the novel computer program COMSTAT.

PubMed

Heydorn, A; Nielsen, A T; Hentzer, M; Sternberg, C; Givskov, M; Ersbøll, B K; Molin, S

2000-10-01

The structural organization of four microbial communities was analysed by a novel computer program, COMSTAT, which comprises ten features for quantifying three-dimensional biofilm image stacks. Monospecies biofilms of each of the four bacteria, Pseudomonas: putida, P. aureofaciens, P. fluorescens and P. aeruginosa, tagged with the green fluorescent protein (GFP) were grown in flow chambers with a defined minimal medium as substrate. Analysis by the COMSTAT program of four variables describing biofilm structure - mean thickness, roughness, substratum coverage and surface to volume ratio - showed that the four Pseudomonas: strains represent different modes of biofilm growth. P. putida had a unique developmental pattern starting with single cells on the substratum growing into micro-colonies, which were eventually succeeded by long filaments and elongated cell clusters. P. aeruginosa colonized the entire substratum, and formed flat, uniform biofilms. P. aureofaciens resembled P. aeruginosa, but had a stronger tendency to form micro-colonies. Finally, the biofilm structures of P. fluorescens had a phenotype intermediate between those of P. putida and P. aureofaciens. Analysis of biofilms of P. aureofaciens growing on 0.03 mM, 0.1 mM or 0.5 mM citrate minimal media showed that mean biofilm thickness increased with increasing citrate concentration. Moreover, biofilm roughness increased with lower citrate concentrations, whereas surface to volume ratio increased with higher citrate concentrations.

Synergistic structures from magnetic freeze casting with surface magnetized alumina particles and platelets.

PubMed

Frank, Michael B; Hei Siu, Sze; Karandikar, Keyur; Liu, Chin-Hung; Naleway, Steven E; Porter, Michael M; Graeve, Olivia A; McKittrick, Joanna

2017-12-01

Magnetic freeze casting utilizes the freezing of water, a low magnetic field and surface magnetized materials to make multi-axis strengthened porous scaffolds. A much greater magnetic moment was measured for larger magnetized alumina platelets compared with smaller particles, which indicated that more platelet aggregation occurred within slurries. This led to more lamellar wall alignment along the magnetic field direction during magnetic freeze casting at 75 mT. Slurries with varying ratios of magnetized particles to platelets (0:1, 1:3, 1:1, 3:1, 7:1, 1:0) produced porous scaffolds with different structural features and degrees of lamellar wall alignment. The greatest mechanical enhancement in the magnetic field direction was identified in the synergistic condition with the highest particle to platelet ratio (7:1). Magnetic freeze casting with varying ratios of magnetized anisotropic and isotropic alumina provided insights about how heterogeneous morphologies aggregate within lamellar walls that impact mechanical properties. Fabrication of strengthened scaffolds with multi-axis aligned porosity was achieved without introducing different solid materials, freezing agents or additives. Resemblance of 7:1 particle to platelet scaffold microstructure to wood light-frame house construction is framed in the context of assembly inspiration being derived from both natural and synthetic sources. Copyright © 2017 Elsevier Ltd. All rights reserved.

Identifying product order with restricted Boltzmann machines

NASA Astrophysics Data System (ADS)

Rao, Wen-Jia; Li, Zhenyu; Zhu, Qiong; Luo, Mingxing; Wan, Xin

2018-03-01

Unsupervised machine learning via a restricted Boltzmann machine is a useful tool in distinguishing an ordered phase from a disordered phase. Here we study its application on the two-dimensional Ashkin-Teller model, which features a partially ordered product phase. We train the neural network with spin configuration data generated by Monte Carlo simulations and show that distinct features of the product phase can be learned from nonergodic samples resulting from symmetry breaking. Careful analysis of the weight matrices inspires us to define a nontrivial machine-learning motivated quantity of the product form, which resembles the conventional product order parameter.

New daily-persistent headache versus tension-type headache.

PubMed

Robbins, Matthew S; Crystal, Sara C

2010-12-01

New daily-persistent headache (NDPH) and chronic tension-type headache (CTTH) are two forms of primary chronic daily headache of long duration that often are similar in their headache manifestations. NDPH distinguishes itself from CTTH and the other forms of chronic daily headache by its continuous head pain from onset. However, despite formalized criteria that specify NDPH must resemble the acute onset of a headache identical to that of CTTH, NDPH commonly has migraine features. Here, we review the available literature on NDPH and compare its clinical features, epidemiology, prognosis, inciting factors, and treatment to CTTH.

New perspectives on the accretion and internal evolution of Venus

NASA Astrophysics Data System (ADS)

O'Rourke, J. G.

2017-12-01

Dichotomous conditions on Earth and Venus present one of the most compelling mysteries in our Solar System. Ongoing debate centers on how the internal dynamics of Venus have shaped its atmospheric composition, surface features, and even habitability over geologic time. In particular, Venus may have resembled Earth for billions of years before suffering catastrophic transformation, or perhaps some accretionary process set these twin planets on divergent paths from the beginning. Unfortunately, the limited quality of decades-old data—particularly the low resolution of radar imagery and global topography from NASA's Magellan mission—harms our ability to draw definite conclusions. But some progress is possible given recent advances in modeling techniques and improved topography derived from stereo images that are available for roughly twenty percent of the surface. Here I present simulations of the interior evolution of Venus consistent with all available constraints and, more importantly, identify future measurements that would dramatically narrow the range of acceptable scenarios. Obtaining high-resolution imagery and topography, along with any information about the temporal history of a magnetic field, is extremely important. Deformation of geologic features constrains the surface heat flow and lithospheric rheology during their formation. Determining whether craters with radar-dark floors (which comprise 80% of the population) are actually embayed by lava flows would finally settle the controversy over catastrophic versus equilibrium resurfacing. If the core of Venus has completely solidified, then the lack of an internally generated magnetic field today is unsurprising. We might expect dynamo action in the past since relatively high mantle temperatures may increase the rate of core cooling—unless a lack of giant impacts during accretion permitted chemical stratification that resists convection. In any case, uncertainty about our celestial cousin reveals a general ignorance of fundamental processes governing planetary evolution and demands renewed effort to gather new observations.

Supernovae 2016bdu and 2005gl, and their link with SN 2009ip-like transients: another piece of the puzzle

NASA Astrophysics Data System (ADS)

Pastorello, A.; Kochanek, C. S.; Fraser, M.; Dong, Subo; Elias-Rosa, N.; Filippenko, A. V.; Benetti, S.; Cappellaro, E.; Tomasella, L.; Drake, A. J.; Harmanen, J.; Reynolds, T.; Shappee, B. J.; Smartt, S. J.; Chambers, K. C.; Huber, M. E.; Smith, K.; Stanek, K. Z.; Christensen, E. J.; Denneau, L.; Djorgovski, S. G.; Flewelling, H.; Gall, C.; Gal-Yam, A.; Geier, S.; Heinze, A.; Holoien, T. W.-S.; Isern, J.; Kangas, T.; Kankare, E.; Koff, R. A.; Llapasset, J.-M.; Lowe, T. B.; Lundqvist, P.; Magnier, E. A.; Mattila, S.; Morales-Garoffolo, A.; Mutel, R.; Nicolas, J.; Ochner, P.; Ofek, E. O.; Prosperi, E.; Rest, A.; Sano, Y.; Stalder, B.; Stritzinger, M. D.; Taddia, F.; Terreran, G.; Tonry, J. L.; Wainscoat, R. J.; Waters, C.; Weiland, H.; Willman, M.; Young, D. R.; Zheng, W.

2018-02-01

Supernova (SN) 2016bdu is an unusual transient resembling SN 2009ip. SN 2009ip-like events are characterized by a long-lasting phase of erratic variability which ends with two luminous outbursts a few weeks apart. The second outburst is significantly more luminous (about 3 mag) than the first. In the case of SN 2016bdu, the first outburst (Event A) reached an absolute magnitude M(r) ~ -15.3 mag, while the second one (Event B) occurred over one month later and reached M(r) ~ -18 mag. By inspecting archival data, a faint source at the position of SN 2016bdu is detectable several times in the past few years. We interpret these detections as signatures of a phase of erratic variability, similar to that experienced by SN 2009ip between 2008 and mid-2012, and resembling the currently observed variability of the luminous blue variable SN 2000ch in NGC 3432. Spectroscopic monitoring of SN 2016bdu during the second peak initially shows features typical of a SN IIn. One month after the Event B maximum, the spectra develop broad Balmer lines with P Cygni profiles and broad metal features. At these late phases, the spectra resemble those of a typical Type II SN. All members of this SN 2009ip-like group are remarkably similar to the Type IIn SN 2005gl. For this object, the claim of a terminal SN explosion is supported by the disappearance of the progenitor star. The similarity with SN 2005gl suggests that all members of this family may finally explode as genuine SNe, although the unequivocal detection of nucleosynthesised elements in their nebular spectra is still missing.

Coupled SPH-FV method with net vorticity and mass transfer

NASA Astrophysics Data System (ADS)

Chiron, L.; Marrone, S.; Di Mascio, A.; Le Touzé, D.

2018-07-01

Recently, an algorithm for coupling a Finite Volume (FV) method, that discretize the Navier-Stokes equations on block structured Eulerian grids, with the weakly-compressible Lagrangian Smoothed Particle Hydrodynamics (SPH) was presented in [16]. The algorithm takes advantage of the SPH method to discretize flow regions close to free-surfaces and of the FV method to resolve the bulk flow and the wall regions. The continuity between the two solutions is guaranteed by overlapping zones. Here we extend the algorithm by adding the possibility to have: 1) net mass transfer between the SPH and FV sub-domains; 2) free-surface across the overlapping region. In this context, particle generation at common boundaries is required to prevent depletion or clustering of particles. This operation is not trivial, because consistency between the Lagrangian and Eulerian description of the flow must be retained to ensure mass conservation. We propose here a new coupling paradigm that extends the algorithm developed in [16] and renders it suitable to test cases where vorticity and free surface significantly pass from one domain to the other. On the SPH side, a novel technique for the creation/deletion of particle was developed. On the FV side, the information recovered from the SPH solver are exploited to improve free surface prediction in a fashion that resemble the Particle Level-Set algorithms. The combination of the two new features was tested and validated in a number of test cases where both vorticity and front evolution are important. Convergence and robustness of the algorithm are shown.

Method of protecting surfaces from abrasion and abrasion resistant articles of manufacture

DOEpatents

Hirschfeld, T.B.

1988-06-09

Surfaces of fabricated structures are protected from damage by impacting particulates by a coating of hard material formed as a mass of thin flexible filaments having root ends secured to the surface and free portions which can flex and overlap to form a resilient cushioning mat which resembles hair or fur. The filamentary coating covers the underlying surface with hard abrasion resistance material while also being compliant and capable of local accommodation to particle impacts. The coating can also function as thermal and/or acoustical insulation and has a friction reducing effect. 11 figs.

New composite spectra of Mars, 0.4-5.7 μm

USGS Publications Warehouse

Erard, Stephane; Calvin, Wendy M.

1997-01-01

About 15 areas were observed in the equatorial regions of Mars by the infrared spectrometers IRS (Mariner 6 and 7) and ISM (Phobos-2). The comparison between the spectra shows a remarkable consistency between two data sets acquired 20 years apart and calibrated independently. This similarity demonstrates the accuracy of ISM calibration above 2 μm, except for a possible stray light contribution above 2.6 μm, on the order of ∼1–2% of the solar flux at 2.7 μm. Most differences in spectral shapes are related to differences in spectral/spatial resolution and viewing geometries. No important variation in surface properties is detected, except for a spot in southern Arabia Terra which has a much deeper hydration feature in IRS spectra; differences in viewing geometries and spatial resolutions do not seem to account for this difference that could result from shifting or dehydration of surface materials. Composite spectra of several types of bright and dark materials are computed by modeling the thermal emission and are completed with telescopic spectra in the visible range. Modeled reflectance in the 3.0–5.7 μm range is consistent with basalts and palagonites. The bright regions and analog palagonite spectra are different from hematite in this range, but resemble several phyllosilicates. We infer that (1) although hematite dominates the spectra in the 0.4- to 2.5-μm range, the silicate-clay host is spectrally active beyond 3 μm and can be identified from this domain; (2) phyllosilicates such as montmorillonite or smectite may be abundant components of the martian soils, although the domain below 3 μm lacks the characteristic features of the most usual terrestrial clay minerals.

The Color and Surface Composition of Mountains on Pluto

NASA Astrophysics Data System (ADS)

Olkin, Catherine B.; Reuter, D. C.; Stern, S. Alan; Young, Leslie; Weaver, Harold A.; Ennico, Kimberly; Binzel, Richard; Cook, Jason C.; Cruikshank, Dale P.; Dalle Ore, Cristina M.; Earle, Alissa M.; Grundy, W. M.; Howett, Carly; Parker, Alex; Protopapa, Silvia; Schmitt, Bernard; Singer, Kelsi N.; Spencer, John R.; Stansberry, John A.; Philippe, Sylvain; New Horizons Science Team

2016-10-01

The New Horizons mission revealed that there are mountains along the western edge of the large glacier that dominates Pluto's anti-Charon hemisphere. This talk will focus on the color and surface composition of the four large mountainous regions named Al Idrisi Montes, Bare Montes, Hillary Montes and Norgay Montes (all feature names are informal).The Al Idrisi Montes are large blocks up to 40 km across and 5 km high that appear to be broken off of the ice crust and transported into Sputnik Planum (Moore et al. 2016). The color of this region as a function of latitude will be presented as well as the color differences between the blocks and the interstitial material between the blocks. Moving south along the edge of Sputnik Planum, the next mountainous region is Bare Montes. Part of the Bare Montes resembles Al Idrisi Montes with its chaotic blocky structure, but there is a significant difference in color between these regions. The Bare Montes are more red than Al Idrisi Montes and this region's color more closely matches the nearby terrain of Cthulhu Regio. Continuing south, to the Hillary and Norgay Montes regions these topographic features become less red with both red and neutral colors on their slopes. The Hillary Montes show both red and neutral colors in the ices surrounding the peaks.This work will provide a quantitative comparison of the color and composition across these 4 mountainous regions using data from the Ralph instrument. Ralph has 4 color filters: blue (400-550 nm), red (540-700 nm), near IR (780-975) and methane filter (860-910 nm) and collects infrared imaging spectrometric data (from 1.25-2.5 microns).This work was supported by NASA's New Horizons project.

Sedimentology and ichnology of the Mafube dinosaur track site (Lower Jurassic, eastern Free State, South Africa): a report on footprint preservation and palaeoenvironment

PubMed Central

Bordy, Emese M.; Reid, Mhairi; Abrahams, Miengah

2016-01-01

Footprint morphology (e.g., outline shape, depth of impression) is one of the key diagnostic features used in the interpretation of ancient vertebrate tracks. Over 80 tridactyl tracks, confined to the same bedding surface in the Lower Jurassic Elliot Formation at Mafube (eastern Free State, South Africa), show large shape variability over the length of the study site. These morphological differences are considered here to be mainly due to variations in the substrate rheology as opposed to differences in the trackmaker’s foot anatomy, foot kinematics or recent weathering of the bedding surface. The sedimentary structures (e.g., desiccation cracks, ripple marks) preserved in association with and within some of the Mafube tracks suggest that the imprints were produced essentially contemporaneous and are true dinosaur tracks rather than undertracks or erosional remnants. They are therefore valuable not only for the interpretation of the ancient environment (i.e., seasonally dry river channels) but also for taxonomic assessments as some of them closely resemble the original anatomy of the trackmaker’s foot. The tracks are grouped, based on size, into two morphotypes that can be identified as Eubrontes-like and Grallator-like ichnogenera. The Mafube morphotypes are tentatively attributable to large and small tridactyl theropod trackmakers, possibly to Dracovenator and Coelophysis based on the following criteria: (a) lack of manus impressions indicative of obligate bipeds; (b) long, slender-digits that are asymmetrical and taper; (c) often end in a claw impression or point; and (d) the tracks that are longer than broad. To enable high-resolution preservation, curation and subsequent remote studying of the morphological variations of and the secondary features in the tracks, low viscosity silicone rubber was used to generate casts of the Mafube tracks. PMID:27635310

Atomic Force Microscopy in Imaging of Viruses and Virus-Infected Cells

PubMed Central

Kuznetsov, Yurii G.; McPherson, Alexander

2011-01-01

Summary: Atomic force microscopy (AFM) can visualize almost everything pertinent to structural virology and at resolutions that approach those for electron microscopy (EM). Membranes have been identified, RNA and DNA have been visualized, and large protein assemblies have been resolved into component substructures. Capsids of icosahedral viruses and the icosahedral capsids of enveloped viruses have been seen at high resolution, in some cases sufficiently high to deduce the arrangement of proteins in the capsomeres as well as the triangulation number (T). Viruses have been recorded budding from infected cells and suffering the consequences of a variety of stresses. Mutant viruses have been examined and phenotypes described. Unusual structural features have appeared, and the unexpectedly great amount of structural nonconformity within populations of particles has been documented. Samples may be imaged in air or in fluids (including culture medium or buffer), in situ on cell surfaces, or after histological procedures. AFM is nonintrusive and nondestructive, and it can be applied to soft biological samples, particularly when the tapping mode is employed. In principle, only a single cell or virion need be imaged to learn of its structure, though normally images of as many as is practical are collected. While lateral resolution, limited by the width of the cantilever tip, is a few nanometers, height resolution is exceptional, at approximately 0.5 nm. AFM produces three-dimensional, topological images that accurately depict the surface features of the virus or cell under study. The images resemble common light photographic images and require little interpretation. The structures of viruses observed by AFM are consistent with models derived by X-ray crystallography and cryo-EM. PMID:21646429

Pygmoid Australomelanesian Homo sapiens skeletal remains from Liang Bua, Flores: Population affinities and pathological abnormalities

PubMed Central

Jacob, T.; Indriati, E.; Soejono, R. P.; Hsü, K.; Frayer, D. W.; Eckhardt, R. B.; Kuperavage, A. J.; Thorne, A.; Henneberg, M.

2006-01-01

Liang Bua 1 (LB1) exhibits marked craniofacial and postcranial asymmetries and other indicators of abnormal growth and development. Anomalies aside, 140 cranial features place LB1 within modern human ranges of variation, resembling Australomelanesian populations. Mandibular and dental features of LB1 and LB6/1 either show no substantial deviation from modern Homo sapiens or share features (receding chins and rotated premolars) with Rampasasa pygmies now living near Liang Bua Cave. We propose that LB1 is drawn from an earlier pygmy H. sapiens population but individually shows signs of a developmental abnormality, including microcephaly. Additional mandibular and postcranial remains from the site share small body size but not microcephaly. PMID:16938848

The use of cue familiarity during retrieval failure is affected by past versus future orientation.

PubMed

Cleary, Anne M

2015-01-01

Cue familiarity that is brought on by cue resemblance to memory representations is useful for judging the likelihood of a past occurrence with an item that fails to actually be retrieved from memory. The present study examined the extent to which this type of resemblance-based cue familiarity is used in future-oriented judgments made during retrieval failure. Cue familiarity was manipulated using a previously-established method of creating differing degrees of feature overlap between the cue and studied items in memory, and the primary interest was in how these varying degrees of cue familiarity would influence future-oriented feeling-of-knowing (FOK) judgments given in instances of cued recall failure. The present results suggest that participants do use increases in resemblance-based cue familiarity to infer an increased likelihood of future recognition of an unretrieved target, but not to the extent that they use it to infer an increased likelihood of past experience with an unretrieved target. During retrieval failure, the increase in future-oriented FOK judgments with increasing cue familiarity was significantly less than the increase in past-oriented recognition judgments with increasing cue familiarity.

Egosyntonic and egodystonic: accounting for continuities and discontinuities between personality traits and personality disorders.

PubMed

Paris, Joel

2015-02-01

Egosyntonic and egodystonic features describe differences between trait-based and state-based mental disorders. Many diagnoses, most particularly personality disorder (PD), show both features. These complex forms of psychopathology are an amalgam of traits and symptoms in which both egosyntonicity and egodystonicity can be present but vary in prominence. This distinction might help resolve the long-standing controversy as to whether PDs are best classified using dimensions or categories. Narrative review. PDs in which egosyntonic features tend to predominate can be understood as amplified trait profiles. PDs associated with highly egodystonic clinical symptoms that more closely resemble major mental disorders may be usefully classified using both categories and dimensions. PDs with stronger egosyntonic features are more suitable for dimensional diagnosis. When egodystonic symptoms are more prominent, categorical diagnoses can be useful.

Signatures of Chemical Evolution in Protostellar Nebulae

NASA Technical Reports Server (NTRS)

Nuth, Joseph A., III; Johnson, Natasha

2011-01-01

A decade ago observers began to take serious notice of the presence of crystalline silicate grains in the dust flowing away from some comets. While crystallinity had been seen in such objects previously, starting with the recognitions by Campins and Ryan (1990) that the 10 micron feature of Comet Halley resembled that of the mineral forsterite, most such observations were either ignored or dismissed as no path to explain such crystalline grains was available in the literature. When it was first suggested that an outward flow must be present to carry annealed silicate grains from the innermost regions of the Solar Nebula out to the regions where comets could form (Nuth, 1999; 2001) this suggestion was also dismissed because no such transport mechanism was known at the time. Since then not only have new models of nebular dynamics demonstrated the reality of long distance outward transport (Ciesla, 2007; 2008; 2009) but examination of older models (Boss, 2004) showed that such transport had been present but had gone unrecognized for many years. The most unassailable evidence for outward nebular transport came with the return of the Stardust samples from Comet Wild2, a Kuiper-belt comet that contained micron-scale grains of high temperature minerals resembling the Calcium-Aluminum Inclusions found in primitive meteorites (Zolensky et aI., 2006) that formed at T > 1400K. Now that outward transport in protostellar nebulae has been firmly established, a re-examination of its consequences for nebular gas is in order that takes into account both the factors that regulate both the outward flow as well as those that likely control the chemical composition of the gas. Laboratory studies of surface catalyzed reactions suggest that a trend toward more highly reduced carbon and nitrogen compounds in the gas phase should be correlated with a general increase in the crystallinity of the dust (Nuth et aI., 2000), but is such a trend actually observable? Unlike the Fischer-Tropsch or the Haber-Bosch reactions used in industry, the surface catalyzed reactions seen in our laboratory do not produce a simple product stream of methane or ammonia, respectively. Instead, such reactions produce a wide range of both aliphatic and aromatic hydrocarbons, as well as reduced nitrogen compounds such as ammonia, amines, amides and imides, as gas phase products together with a heavy, macromolecular, kerogen-like surface coating that remains on the grains. While CO and N2 will certainly be depleted by conversion into more complex and less volatile species via reaction on grain surfaces, it may be very difficult to monitor such changes from outside the system.

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

Li, Haoxiang; Zhou, Xiaoqing; Nummy, Thomas

Layered nickelates have the potential for exotic physics similar to high T C superconducting cuprates as they have similar crystal structures and these transition metals are neighbors in the periodic table. Here we present an angle-resolved photoemission spectroscopy (ARPES) study of the trilayer nickelate La 4Ni 3O 10 revealing its electronic structure and correlations, finding strong resemblances to the cuprates as well as a few key differences. We find a large hole Fermi surface that closely resembles the Fermi surface of optimally hole-doped cuprates, including its d x2-y2 orbital character, hole filling level, and strength of electronic correlations. However, inmore » contrast to cuprates, La 4Ni 3O 10 has no pseudogap in the d x2-y2 band, while it has an extra band of principally d 3z2-r2 orbital character, which presents a low temperature energy gap. Furthermore, these aspects drive the nickelate physics, with the differences from the cuprate electronic structure potentially shedding light on the origin of superconductivity in the cuprates.« less

A new serially transplantable human prostatic cancer (HONDA) in nude mice.

PubMed

Ito, Y Z; Nakazato, Y

1984-08-01

A new serially transplantable human prostatic cancer (HONDA) in nude mice was established from a patient with metastatic prostate carcinoma. The tumor grows well in male nude mice. Doubling time of the tumor weight at passage #13 was 9.5 +/- 0.87 days (mean +/- SD). The tumor retains the original histological features of adenocarcinoma even after 6 years of continuous passage. High levels of human prostatic acid phosphatase were detected by radioimmunoassay in sera from the tumor-bearing mice. The tumor cells contain human prostate specific antigen. Electron microscopy showed particles resembling type A retroviruses in cisterns of endoplasmic reticulum, and particles resembling type C retroviruses in the intercellular space of the tumor cells. The tumor grew well in female mice treated with testosterone, but not in untreated female mice or castrated male mice.

Shatter cones at the Keurusselkä impact structure and their relation to local jointing

NASA Astrophysics Data System (ADS)

Hasch, Maximilian; Reimold, Wolf Uwe; Raschke, Ulli; Zaag, Patrice Tristan

2016-08-01

Shatter cones are the only distinct meso- to macroscopic recognition criterion for impact structures, yet not all is known about their formation. The Keurusselkä impact structure, Finland, is interesting in that it presents a multitude of well-exposed shatter cones in medium- to coarse-grained granitoids. The allegedly 27 km wide Keurusselkä impact structure was formed about 1150 Ma ago in rocks of the Central Finland Granitoid Complex. Special attention was paid in this work to possible relationships between shatter cones and local, as well as regionally occurring, fracture or joint systems. A possible shatter cone find outside the previously suggested edge of the structure could mean that the Keurusselkä impact structure is larger than previously thought. The spacing between joints/fractures from regional joint systems was influenced by the impact, but impact-induced fractures strongly follow the regional joint orientation trends. There is a distinct relationship between shatter cones and joints: shatter cones occur on and against joint surfaces of varied orientations and belonging to the regional orientation trends. Planar fractures (PF) and planar deformation features (PDF) were found in three shatter cone samples from the central-most part of the impact structure, whereas other country rock samples from the same level of exposure but further from the assumed center lack shock deformation features. PDF occurrence is enhanced within 5 mm of shatter cone surfaces, which is interpreted to suggest that shock wave reverberation at preimpact joints could be responsible for this local enhancement of shock deformation. Some shatter cone surfaces are coated with a quasi-opaque material which is also found in conspicuous veinlets that branch off from shatter cone surfaces and resemble pseudotachylitic breccia veins. The vein-filling is composed of two mineral phases, one of which could be identified as a montmorillonitic phyllosilicate. The second phase could not be identified yet. The original composition of the fill could not be determined. Further work is required on this material. Observed joints and fractures were discussed against findings from Barringer impact crater. They show that impact-induced joints in the basement rock do not follow impact-specific orientations (such as radial, conical, or concentric).

Integrated gas turbine engine-nacelle

NASA Technical Reports Server (NTRS)

Adamson, A. P.; Sargisson, D. F.; Stotler, C. L., Jr. (Inventor)

1979-01-01

A nacelle for use with a gas turbine engine is provided with an integral webbed structure resembling a spoked wheel for rigidly interconnecting the nacelle and engine. The nacelle is entirely supported in its spacial relationship with the engine by means of the webbed structure. The inner surface of the nacelle defines the outer limits of the engine motive fluid flow annulus, while the outer surface of the nacelle defines a streamlined envelope for the engine.

Design of a solar concentrator considering arbitrary surfaces

NASA Astrophysics Data System (ADS)

Jiménez-Rodríguez, Martín.; Avendaño-Alejo, Maximino; Verduzco-Grajeda, Lidia Elizabeth; Martínez-Enríquez, Arturo I.; García-Díaz, Reyes; Díaz-Uribe, Rufino

2017-10-01

We study the propagation of light in order to efficiently redirect the reflected light on photocatalytic samples placed inside a commercial solar simulator, and we have designed a small-scale prototype of Cycloidal Collectors (CCs), resembling a compound parabolic collector. The prototype consists of either cycloidal trough or cycloidal collector having symmetry of rotation, which has been designed considering an exact ray tracing assuming a bundle of rays propagating parallel to the optical axis and impinging on a curate cycloidal surface, obtaining its caustic surface produced by reflection.

Synovial sarcoma of the jaw in a dog.

PubMed

Griffith, J W; Frey, R A; Sharkey, F E

1987-05-01

A case of synovial sarcoma of the jaw with pulmonary metastasis is described in a dog. It appears to be a rare or underdiagnosed neoplasm in animals and not previously reported in the jaw. Its diagnostic microscopic features are the biphasic cellular pattern and cleft formations. It may otherwise resemble haemangiopericytoma, malignant fibrous histiocytoma, reticulum cell sarcoma, fibrosarcoma, or giant-cell tumour of soft tissue.

Effects of high-temperature gas dealkalization on surface mechanical properties of float glass

NASA Astrophysics Data System (ADS)

Senturk, Ufuk

The surface topography, and the near-surface structure and mechanical property changes on float glass, that was treated in atmospheres containing SOsb2, HCl, and 1,1 difluoroethane (DFE) gases, at temperatures in the glass transition region, were studied. Structure was investigated using surface sensitive infrared spectroscopy techniques (attenuated total reflectance (ATR) and diffuse reflectance (DRIFT)) and the topography was evaluated using atomic force microscopy (AFM). The results obtained from the two FTIR methods were in agreement with each other. Mechanical property characteristics of the surface were determined by measuring microhardness using a recording microindentation set-up. A simple analysis performed on the three hardness calculation methods-LVH, LVHsb2, and Lsb2VH-indicated that LVH and LVHsb2 are less effected by measurement errors and are better suited for the calculation of hardness. Contact damage characteristics of the treated glass was also studied by monitoring the crack initiation behavior during indentation, using acoustic emission. The results of the studies, aiming for the understanding of the structure, topography, and hardness property changes indicate that the treatment parameters-temperature, time, and treatment atmosphere conditions-are significant factors influencing these properties. The analysis of these results suggest a relation to exist between the three properties. This relation is used in understanding the surface mechanical properties of the treated float glasses. The difference in the thermal expansion coefficients between the dealkalized surface and bulk, the nature of surface structure changes, structural relaxation, surface water content, and glass transformation temperature are identified as the major factors having an influence on the properties. A model connecting these features is suggested. A difference in the structure, hardness, and topography on the air and tin sides of float glass is also shown to exist. The contact damage behavior of the treated surfaces is shown to differ from those of untreated surfaces, for SOsb2-treated float glass, where the crack initiation characteristics indicate crack formation from the surface and the indenter tip, different than the expected anomalous deformation. This behavior resembles that of a silica glass deformation on the surface, which is in agreement with the other foundations in this study.

Unusual dynamic properties of water near the ice-binding plane of hyperactive antifreeze protein

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

Kuffel, Anna; Czapiewski, Dariusz; Zielkiewicz, Jan, E-mail: jaz@chem.pg.gda.pl

2015-10-07

The dynamical properties of solvation water of hyperactive antifreeze protein from Choristoneura fumiferana (CfAFP) are analyzed and discussed in context of its antifreeze activity. The protein comprises of three well-defined planes and one of them binds to the surface of ice. The dynamical properties of solvation water around each of these planes were analyzed separately; the results are compared with the dynamical properties of solvation water of ice around its two crystallographic planes: basal and prism. Three main conclusions are inferred from our investigations. The first one is that the solvation shell of CfAFP does not seem to be particularlymore » far-ranged, at least not beyond what is usually observed for proteins that do not interact with ice. Therefore, it does not appear to us that the antifreeze activity is enhanced by a long-ranged retardation of water mobility. Also the correlation between the collective mobility of water and the collective mobility of protein atoms highly resembles the one measured for the protein that does not interact with ice. Our second conclusion is that the dynamical properties of solvation water of CfAFP are non-uniform. The dynamics of solvation water of ice-binding plane is, in some respects, different from the dynamics of solvation water of the two remaining planes. The feature that distinguishes the dynamics of solvation water of the three planes is the activation energy of diffusion process. The third conclusion is that—from the three analyzed solvation shells of CfAFP—the dynamical properties of solvation water of the ice-binding plane resemble the most the properties of solvation water of ice; note, however, that these properties still clearly differ from the dynamic properties of solvation water of ice.« less

Photo- and electropatterning of hydrogel-encapsulated living cell arrays.

PubMed

Albrecht, Dirk R; Tsang, Valerie Liu; Sah, Robert L; Bhatia, Sangeeta N

2005-01-01

Living cells have the potential to serve as sensors, naturally integrating the response to stimuli to generate predictions about cell fate (e.g., differentiation, migration, proliferation, apoptosis). Miniaturized arrays of living cells further offer the capability to interrogate many cells in parallel and thereby enable high-throughput and/or combinatorial assays. However, the interface between living cells and synthetic chip platforms is a critical one wherein the cellular phenotype must be preserved to generate useful signals. While some cell types retain tissue-specific features on a flat (2-D) surface, it has become increasingly apparent that a 3-D physical environment will be required for others. In this paper, we present two independent methods for creating living cell arrays that are encapsulated within a poly(ethylene glycol)-based hydrogel to create a local 3-D microenvironment. First, 'photopatterning' selectively crosslinks hydrogel microstructures containing living cells with approximately 100 microm feature size. Second, 'electropatterning' utilizes dielectrophoretic forces to position cells within a prepolymer solution prior to crosslinking, forming cell patterns with micron resolution. We further combine these methods to obtain hierarchical control of cell positioning over length scales ranging from microns to centimeters. This level of microenvironmental control should enable the fabrication of next-generation cellular microarrays in which robust 3-D cultures of cells are presented with appropriate physical and chemical cues and, consequently, report on cellular responses that resemble in vivo behavior.

2004 EW95: A Phyllosilicate-bearing Carbonaceous Asteroid in the Kuiper Belt

NASA Astrophysics Data System (ADS)

Seccull, Tom; Fraser, Wesley C.; Puzia, Thomas H.; Brown, Michael E.; Schönebeck, Frederik

2018-03-01

Models of the Solar System’s dynamical evolution predict the dispersal of primitive planetesimals from their formative regions among the gas-giant planets due to the early phases of planetary migration. Consequently, carbonaceous objects were scattered both into the outer asteroid belt and out to the Kuiper Belt. These models predict that the Kuiper Belt should contain a small fraction of objects with carbonaceous surfaces, though to date, all reported visible reflectance spectra of small Kuiper Belt Objects (KBOs) are linear and featureless. We report the unusual reflectance spectrum of a small KBO, (120216) 2004 EW95, exhibiting a large drop in its near-UV reflectance and a broad shallow optical absorption feature centered at ∼700 nm, which is detected at greater than 4σ significance. These features, confirmed through multiple epochs of spectral photometry and spectroscopy, have respectively been associated with ferric oxides and phyllosilicates. The spectrum bears striking resemblance to those of some C-type asteroids, suggesting that 2004 EW95 may share a common origin with those objects. 2004 EW95 orbits the Sun in a stable mean motion resonance with Neptune, at relatively high eccentricity and inclination, suggesting it may have been emplaced there by some past dynamical instability. These results appear consistent with the aforementioned model predictions and are the first to show a reliably confirmed detection of silicate material on a small KBO.

Cumulates, Dykes and Pressure Solution in the Ice-Salt Mantle of Europa: Geological Consequences of Pressure Dependent Liquid Compositions and Volume Changes During Ice-Salt Melting Reactions.

NASA Astrophysics Data System (ADS)

Day, S.; Asphaug, E.; Bruesch, L.

2002-12-01

Water-salt analogue experiments used to investigate cumulate processes in silicate magmas, along with observations of sea ice and ice shelf behaviour, indicate that crystal-melt separation in water-salt systems is a rapid and efficient process even on scales of millimetres and minutes. Squeezing-out of residual melts by matrix compaction is also predicted to be rapid on geological timescales. We predict that the ice-salt mantle of Europa is likely to be strongly stratified, with a layered structure predictable from density and phase relationships between ice polymorphs, aqueous saline solutions and crystalline salts such as hydrated magnesium sulphates (determined experimentally by, inter alia, Hogenboom et al). A surface layer of water ice flotation cumulate will be separated from denser salt cumulates by a cotectic horizon. This cotectic horizon will be both the site of subsequent lowest-temperature melting and a level of neutral buoyancy for the saline melts produced. Initial melting will be in a narrow depth range owing to increasing melting temperature with decreasing pressure: the phase relations argue against direct melt-though to the surface unless vesiculation occurs. Overpressuring of dense melts due to volume expansion on cotectic melting is predicted to lead to lateral dyke emplacement and extension above the dyke tips. Once the liquid leaves the cotectic, melting of water ice will involve negative volume change. Impact-generated melts will drain downwards through the fractured zones beneath crater floors. A feature in the complex crater Mannan'an, with elliptical ring fractures around a conical depression with a central pit, bears a close resemblance to Icelandic glacier collapse cauldrons produced by subglacial eruptions. Other structures resembling Icelandic cauldrons occur along Europan banded structures, while resurgence of ice rubble within collapse structures may produce certain types of chaos region. More general contraction of the ice mantle due to melting may be accommodated across banded structures by deformation and pressure solution. Expansion and contraction during different parts of a melting (and freezing) episode may account for the complexity of banded structures on Europa and inconsistent offsets of older structures across them.

Using 3D printing techniques to create an anthropomorphic thorax phantom for medical imaging purposes.

PubMed

Hazelaar, Colien; van Eijnatten, Maureen; Dahele, Max; Wolff, Jan; Forouzanfar, Tymour; Slotman, Ben; Verbakel, Wilko F A R

2018-01-01

Imaging phantoms are widely used for testing and optimization of imaging devices without the need to expose humans to irradiation. However, commercially available phantoms are commonly manufactured in simple, generic forms and sizes and therefore do not resemble the clinical situation for many patients. Using 3D printing techniques, we created a life-size phantom based on a clinical CT scan of the thorax from a patient with lung cancer. It was assembled from bony structures printed in gypsum, lung structures consisting of airways, blood vessels >1 mm, and outer lung surface, three lung tumors printed in nylon, and soft tissues represented by silicone (poured into a 3D-printed mold). Kilovoltage x-ray and CT images of the phantom closely resemble those of the real patient in terms of size, shapes, and structures. Surface comparison using 3D models obtained from the phantom and the 3D models used for printing showed mean differences <1 mm for all structures. Tensile tests of the materials used for the phantom show that the phantom is able to endure radiation doses over 24,000 Gy. It is feasible to create an anthropomorphic thorax phantom using 3D printing and molding techniques. The phantom closely resembles a real patient in terms of spatial accuracy and is currently being used to evaluate x-ray-based imaging quality and positional verification techniques for radiotherapy. © 2017 American Association of Physicists in Medicine.

A bicontinuous tetrahedral structure in a liquid-crystalline lipid

NASA Astrophysics Data System (ADS)

Longley, William; McIntosh, Thomas J.

1983-06-01

The structure of most lipid-water phases can be visualized as an ordered distribution of two liquid media, water and hydrocarbons, separated by a continuous surface covered by the polar groups of the lipid molecules1. In the cubic phases in particular, rod-like elements are linked into three-dimensional networks1,2. Two of these phases (space groups Ia3d and Pn3m) contain two such three-dimensional networks mutually inter-woven and unconnected. Under the constraints of energy minimization3, the interface between the components in certain of these `porous fluids' may well resemble one of the periodic minimal surface structures of the type described mathematically by Schwarz4,5. A structure of this sort has been proposed for the viscous isotropic (cubic) form of glycerol monooleate (GMO) by Larsson et al.6 who suggested that the X-ray diagrams of Lindblom et al.7 indicated a body-centred crystal structure in which lipid bilayers might be arranged as in Schwarz's octahedral surface4. We have now found that at high water contents, a primitive cubic lattice better fits the X-ray evidence with the material in the crystal arranged in a tetrahedral way. The lipid appears to form a single bilayer, continuous in three dimensions, separating two continuous interlinked networks of water. Each of the water networks has the symmetry of the diamond crystal structure and the bilayer lies in the space between them following a surface resembling Schwarz's tetrahedral surface4.

Interpreting Quasi-Thermal Effects in Ultrafast Spectroscopy of Hydrogen-Bonded Systems.

PubMed

Stingel, Ashley M; Petersen, Poul B

2018-03-15

Vibrational excitation of molecules in the condensed phase relaxes through vibrational modes of decreasing energy to ultimately generate an equilibrium state in which the energy is distributed among low-frequency modes. In ultrafast vibrational spectroscopy, changes in the vibrational features of hydrogen-bonded NH and OH stretch modes are typically observed to persist long after these high-frequency vibrations have relaxed. Due to the resemblance to the spectral changes caused by heating the sample, these features are typically described as arising from a hot ground state. However, these spectral features appear on ultrafast time scales that are much too fast to result from a true thermal state, and significant differences between the thermal difference spectrum and the induced quasi-thermal changes in ultrafast spectroscopy are often observed. Here, we examine and directly compare the thermal and quasi-thermal responses of the hydrogen-bonded homodimer of 7-azaindole with temperature-dependent FTIR spectroscopy and ultrafast mid-IR continuum spectroscopy. We find that the thermal difference spectra contain contributions from both dissociation of the hydrogen bonds and from frequency shifts due to changes in the thermal population of low-frequency modes. The transient spectra in ultrafast vibrational spectroscopy are also found to contain two contributions: initial frequency shifts over 2.3 ± 0.11 ps associated with equilibration of the initial excitation, and frequency shifts associated with the excitation of several fingerprint modes, which decay over 21.8 ± 0.11 ps, giving rise to a quasi-thermal response caused by a distribution of fingerprint modes being excited within the sample ensemble. This resembles the thermal frequency shifts due to population changes of low-frequency modes, but not the overall thermal spectrum, which is dominated by features caused by dimer dissociation. These findings provide insight into the changes in the vibrational spectrum from different origins and are important for assigning, analyzing, and comparing features in thermal and ultrafast vibrational spectroscopy of hydrogen-bonded complexes.

The cranial anatomy of the neornithischian dinosaur Thescelosaurus neglectus

PubMed Central

2014-01-01

Though the dinosaur Thescelosaurus neglectus was first described in 1913 and is known from the relatively fossiliferous Lance and Hell Creek formations in the Western Interior Basin of North America, the cranial anatomy of this species remains poorly understood. The only cranial material confidently referred to this species are three fragmentary bones preserved with the paratype, hindering attempts to understand the systematic relationships of this taxon within Neornithischia. Here the cranial anatomy of T. neglectus is fully described for the first time based on two specimens that include well-preserved cranial material (NCSM 15728 and TLAM.BA.2014.027.0001). Visual inspection of exposed cranial elements of these specimens is supplemented by detailed CT data from NCSM 15728 that enabled the examination of otherwise unexposed surfaces, facilitating a complete description of the cranial anatomy of this species. The skull of T. neglectus displays a unique combination of plesiomorphic and apomorphic traits. The premaxillary and ‘cheek’ tooth morphologies are relatively derived, though less so than the condition seen in basal iguanodontians, suggesting that the high tooth count present in the premaxillae, maxillae, and dentaries may be related to the extreme elongation of the skull of this species rather than a retention of the plesiomorphic condition. The morphology of the braincase most closely resembles the iguanodontians Dryosaurus and Dysalotosaurus, especially with regard to the morphology of the prootic. One autapomorphic feature is recognized for the first time, along with several additional cranial features that differentiate this species from the closely related and contemporaneous Thescelosaurus assiniboiensis. Published phylogenetic hypotheses of neornithischian dinosaur relationships often differ in the placement of the North American taxon Parksosaurus, with some recovering a close relationship with Thescelosaurus and others with the South American taxon Gasparinisaura, but never both at the same time. The new morphological observations presented herein, combined with re-examination of the holotype of Parksosaurus, suggest that Parksosaurus shares a closer relationship with Thescelosaurus than with Gasparinisaura, and that many of the features previously cited to support a relationship with the latter taxon are either also present in Thescelosaurus, are artifacts of preservation, or are the result of incomplete preparation and inaccurate interpretation of specimens. Additionally, the overall morphology of the skull and lower jaws of both Thescelosaurus and Parksosaurus also closely resemble the Asian taxa Changchunsaurus and Haya, though the interrelationships of these taxa have yet to be tested in a phylogenetic analysis that includes these new morphological data for T. neglectus. PMID:25405076

Memory instability as a gateway to generalization

PubMed Central

2018-01-01

Our present frequently resembles our past. Patterns of actions and events repeat throughout our lives like a motif. Identifying and exploiting these patterns are fundamental to many behaviours, from creating grammar to the application of skill across diverse situations. Such generalization may be dependent upon memory instability. Following their formation, memories are unstable and able to interact with one another, allowing, at least in principle, common features to be extracted. Exploiting these common features creates generalized knowledge that can be applied across varied circumstances. Memory instability explains many of the biological and behavioural conditions necessary for generalization and offers predictions for how generalization is produced. PMID:29554094

The identification of two unusual types of homemade ammunition.

PubMed

Lee, Hsieh-Chang; Meng, Hsien-Hui

2012-07-01

Illegal homemade ammunition is commonly used by criminals to commit crimes in Taiwan. Two unusual types of homemade ammunition that most closely resembling genuine ammunition are studied here. Their genuine counterparts are studied as the control samples for the purpose of comparison. Unfired ammunition is disassembled, and the morphological, dimensional, and compositional features of the bullet and cartridge case are examined. Statistical tests are employed to distinguish the dimensional differences between homemade and genuine ammunitions. Manufacturing marks on head stamps of the cartridge case are carefully examined. Compositional features of propellant powders, primer mixtures, and gunshot residues are also analyzed. The results reveal that the morphological, dimensional, and compositional features of major parts of the ammunition can be employed to differentiate homemade cartridges from genuine ones. Among these features, tool marks on the head stamps left by the bunter can be used to trace the origin of ammunition. © 2012 American Academy of Forensic Sciences.

Intrinsic two-dimensional features as textons

NASA Technical Reports Server (NTRS)

Barth, E.; Zetzsche, C.; Rentschler, I.

1998-01-01

We suggest that intrinsic two-dimensional (i2D) features, computationally defined as the outputs of nonlinear operators that model the activity of end-stopped neurons, play a role in preattentive texture discrimination. We first show that for discriminable textures with identical power spectra the predictions of traditional models depend on the type of nonlinearity and fail for energy measures. We then argue that the concept of intrinsic dimensionality, and the existence of end-stopped neurons, can help us to understand the role of the nonlinearities. Furthermore, we show examples in which models without strong i2D selectivity fail to predict the correct ranking order of perceptual segregation. Our arguments regarding the importance of i2D features resemble the arguments of Julesz and co-workers regarding textons such as terminators and crossings. However, we provide a computational framework that identifies textons with the outputs of nonlinear operators that are selective to i2D features.

Practiced musical style shapes auditory skills.

PubMed

Vuust, Peter; Brattico, Elvira; Seppänen, Miia; Näätänen, Risto; Tervaniemi, Mari

2012-04-01

Musicians' processing of sounds depends highly on instrument, performance practice, and level of expertise. Here, we measured the mismatch negativity (MMN), a preattentive brain response, to six types of musical feature change in musicians playing three distinct styles of music (classical, jazz, and rock/pop) and in nonmusicians using a novel, fast, and musical sounding multifeature MMN paradigm. We found MMN to all six deviants, showing that MMN paradigms can be adapted to resemble a musical context. Furthermore, we found that jazz musicians had larger MMN amplitude than all other experimental groups across all sound features, indicating greater overall sensitivity to auditory outliers. Furthermore, we observed a tendency toward shorter latency of the MMN to all feature changes in jazz musicians compared to band musicians. These findings indicate that the characteristics of the style of music played by musicians influence their perceptual skills and the brain processing of sound features embedded in music. © 2012 New York Academy of Sciences.

Approximation-based common principal component for feature extraction in multi-class brain-computer interfaces.

PubMed

Hoang, Tuan; Tran, Dat; Huang, Xu

2013-01-01

Common Spatial Pattern (CSP) is a state-of-the-art method for feature extraction in Brain-Computer Interface (BCI) systems. However it is designed for 2-class BCI classification problems. Current extensions of this method to multiple classes based on subspace union and covariance matrix similarity do not provide a high performance. This paper presents a new approach to solving multi-class BCI classification problems by forming a subspace resembled from original subspaces and the proposed method for this approach is called Approximation-based Common Principal Component (ACPC). We perform experiments on Dataset 2a used in BCI Competition IV to evaluate the proposed method. This dataset was designed for motor imagery classification with 4 classes. Preliminary experiments show that the proposed ACPC feature extraction method when combining with Support Vector Machines outperforms CSP-based feature extraction methods on the experimental dataset.

Manufacturing Methods and Technology Application of High Energy Laser Welding Process.

DTIC Science & Technology

1980-08-01

surface appearance and the lowest porosity of the three beam shapes evaluated. Welds made with the pure annular beam resembled a TIG weld in both surface...improper starts and stops when welding with a conventional MIG or TIG process. Figure 16 left and center illustrates cracking due to fast freezing conditions...REPORT RL-82-2 0 MANUFACTURING METHODS AND TECHNOLOGY APPLICATION _OF HIGH ENERGY LASER WELDING PROCESS 0John V. Melonas Structures Directorate, U S

Toward Theoretical Foundations of Resistive Force Theory of Granular-Structural Interaction, with Expansions to Flexible Locomotors

DTIC Science & Technology

2015-05-07

the proper depth-dependent pressure distribution before intruder motion begins. We model the intruder as a rigid surface within the granular body by...assigning corresponding planar nodes to move as a rigid body at a constant rate. This resembles a fully rough surface due to the no-slip condition, no...Stokesian fluids. Despite its remarkable capability to predict experimental locomotion and force distributions on mobile bodies in granular media, there is

The IR emission features - Emission from PAH molecules and amorphous carbon particles

NASA Technical Reports Server (NTRS)

Allamandola, L. J.; Tielens, A. G. G. M.; Barker, J. R.

1987-01-01

Techniques for the assessment of the importance of the various forms of PAHs, and recent infrared observations concerning the PAH problem, are considered. Spectroscopic data suggest that the observed interstellar spectrum is due to both free molecule-sized PAHs producing the narrow features, and amorphous carbon particles contributing to the broad underlying components. Explanations for the multicomponent emission spectrum are discussed. A model of the emission mechanism for the example of chrysene is presented, and an exact treatment of the IR fluorescence from highly vibrationally excited large molecules shows that species containing 20-30 carbon atoms are responsible for the narrow features, although the spectra more closely resemble those of amorphous carbon particles. It is suggested that future emphasis should be placed on the spatial characteristics of the component spectra.

Craters Near Nilokeras Scopulus

NASA Image and Video Library

2015-03-04

This image from NASA Mars Reconnaissance Orbiter of craters near Nilokeras Scopulus shows two pits partially filled with lumpy material, probably trapped dust that blew in from the atmosphere. This image shows two pits partially filled with lumpy material, probably trapped dust that blew in from the atmosphere. The pits themselves resemble impact craters, but they are part of a chain of similar features aligned with nearby faults, so they could be collapse features instead. Note also the tracks left by rolling boulders at the bottom of the craters. Nilokeras Scopulus is the name for the cliff, about 756 kilometers long, in the northern hemisphere of Mars where these craters are located. It was named based on an albedo (brightness) feature mapped by astronomer E. M. Antoniadi in 1930. http://photojournal.jpl.nasa.gov/catalog/PIA19304

Whisking mechanics and active sensing

PubMed Central

Bush, Nicholas E; Solla, Sara A

2017-01-01

We describe recent advances in quantifying the three-dimensional (3D) geometry and mechanics of whisking. Careful delineation of relevant 3D reference frames reveals important geometric and mechanical distinctions between the localization problem (‘where’ is an object) and the feature extraction problem (‘what’ is an object). Head-centered and resting-whisker reference frames lend themselves to quantifying temporal and kinematic cues used for object localization. The whisking-centered reference frame lends itself to quantifying the contact mechanics likely associated with feature extraction. We offer the ‘windowed sampling’ hypothesis for active sensing: that rats can estimate an object’s spatial features by integrating mechanical information across whiskers during brief (25–60 ms) windows of ‘haptic enclosure’ with the whiskers, a motion that resembles a hand grasp. PMID:27632212

Whisking mechanics and active sensing.

PubMed

Bush, Nicholas E; Solla, Sara A; Hartmann, Mitra Jz

2016-10-01

We describe recent advances in quantifying the three-dimensional (3D) geometry and mechanics of whisking. Careful delineation of relevant 3D reference frames reveals important geometric and mechanical distinctions between the localization problem ('where' is an object) and the feature extraction problem ('what' is an object). Head-centered and resting-whisker reference frames lend themselves to quantifying temporal and kinematic cues used for object localization. The whisking-centered reference frame lends itself to quantifying the contact mechanics likely associated with feature extraction. We offer the 'windowed sampling' hypothesis for active sensing: that rats can estimate an object's spatial features by integrating mechanical information across whiskers during brief (25-60ms) windows of 'haptic enclosure' with the whiskers, a motion that resembles a hand grasp. Copyright © 2016. Published by Elsevier Ltd.

Structure of Bombyx mori Densovirus 1, a Silkworm Pathogen▿‡

PubMed Central

Kaufmann, Bärbel; El-Far, Mohamed; Plevka, Pavel; Bowman, Valorie D.; Li, Yi; Tijssen, Peter; Rossmann, Michael G.

2011-01-01

Bombyx mori densovirus 1 (BmDNV-1), a major pathogen of silkworms, causes significant losses to the silk industry. The structure of the recombinant BmDNV-1 virus-like particle has been determined at 3.1-Å resolution using X-ray crystallography. It is the first near-atomic-resolution structure of a virus-like particle within the genus Iteravirus. The particles consist of 60 copies of the 55-kDa VP3 coat protein. The capsid protein has a β-barrel “jelly roll” fold similar to that found in many diverse icosahedral viruses, including archaeal, bacterial, plant, and animal viruses, as well as other parvoviruses. Most of the surface loops have little structural resemblance to other known parvovirus capsid proteins. In contrast to vertebrate parvoviruses, the N-terminal β-strand of BmDNV-1 VP3 is positioned relative to the neighboring 2-fold related subunit in a “domain-swapped” conformation, similar to findings for other invertebrate parvoviruses, suggesting domain swapping is an evolutionarily conserved structural feature of the Densovirinae. PMID:21367906

Three-dimensional reconstructions come to life--interactive 3D PDF animations in functional morphology.

PubMed

van de Kamp, Thomas; dos Santos Rolo, Tomy; Vagovič, Patrik; Baumbach, Tilo; Riedel, Alexander

2014-01-01

Digital surface mesh models based on segmented datasets have become an integral part of studies on animal anatomy and functional morphology; usually, they are published as static images, movies or as interactive PDF files. We demonstrate the use of animated 3D models embedded in PDF documents, which combine the advantages of both movie and interactivity, based on the example of preserved Trigonopterus weevils. The method is particularly suitable to simulate joints with largely deterministic movements due to precise form closure. We illustrate the function of an individual screw-and-nut type hip joint and proceed to the complex movements of the entire insect attaining a defence position. This posture is achieved by a specific cascade of movements: Head and legs interlock mutually and with specific features of thorax and the first abdominal ventrite, presumably to increase the mechanical stability of the beetle and to maintain the defence position with minimal muscle activity. The deterministic interaction of accurately fitting body parts follows a defined sequence, which resembles a piece of engineering.

Creating Polymer Hydrogel Microfibres with Internal Alignment via Electrical and Mechanical Stretching

PubMed Central

Zhang, Shuming; Liu, Xi; Barreto-Ortiz, Sebastian F.; Yu, Yixuan; Ginn, Brian; DeSantis, Nicholas; Hutton, Daphne L; Grayson, Warren; Cui, Fu-Zhai; Korgel, Brian A.; Gerecht, Sharon; Mao, Hai-Quan

2014-01-01

Hydrogels have been widely used for 3-dimensional (3D) cell culture and tissue regeneration due to their tunable biochemical and physicochemical properties as well as their high water content, which resembles the aqueous microenvironment of the natural extracellular matrix. While many properties of natural hydrogel matrices are modifiable, their intrinsic isotropic structure limits the control over cellular organization, which is critical to restore tissue function. Here we report a generic approach to incorporate alignment topography inside the hydrogel matrix using a combination of electrical and mechanical stretching. Hydrogel fibres with uniaxial alignment were prepared from aqueous solutions of natural polymers such as alginate, fibrin, gelatin, and hyaluronic acid under ambient conditions. The unique internal alignment feature drastically enhances the mechanical properties of the hydrogel microfibres. Furthermore, the facile, organic solvent-free processing conditions are amenable to the incorporation of live cells within the hydrogel fibre or on the fibre surface; both approaches effectively induce cellular alignment. This work demonstrates a versatile and scalable strategy to create aligned hydrogel microfibres from various natural polymers. PMID:24439410

Early Mars Climate Revisited With a Global Probability Map of Martian Valley Network Origin and Distribution

NASA Astrophysics Data System (ADS)

Grau Galofre, A.; Jellinek, M.; Osinski, G. R.

2016-12-01

Valley networks are among the most arresting features on the surface of Mars. Their provocative morphologic resemblance to river valleys on Earth has lead many scientists to argue for Martian river valleys in a "warm and wet" climate scenario, with conditions similar to the terrestrial mid-to-low latitudes. However, this warm scenario is difficult to reconcile with climate models for an Early Mars receiving radiation from a fainter young Sun. Moreover, recent models suggest a colder scenario, with conditions more similar to present day Greenland or Antarctica. Here we use three independent characterization schemes to show quantitative evidence for fluvial, glacial, groundwater sapping and subglacial meltwater channels to build the first global probability map of Martian valley networks. We distinguish a SW-NE corridor of fluvial drainage networks spanning latitudes from 30ºS to 30ºN. We identify additional widespread patterns related to glaciation, subglacial drainage and channels incised by groundwater springs. This global characterization of Martian valleys has profound implications for the average climate of early Mars as well as its variability in space and time.

Three-Dimensional Reconstructions Come to Life – Interactive 3D PDF Animations in Functional Morphology

PubMed Central

van de Kamp, Thomas; dos Santos Rolo, Tomy; Vagovič, Patrik; Baumbach, Tilo; Riedel, Alexander

2014-01-01

Digital surface mesh models based on segmented datasets have become an integral part of studies on animal anatomy and functional morphology; usually, they are published as static images, movies or as interactive PDF files. We demonstrate the use of animated 3D models embedded in PDF documents, which combine the advantages of both movie and interactivity, based on the example of preserved Trigonopterus weevils. The method is particularly suitable to simulate joints with largely deterministic movements due to precise form closure. We illustrate the function of an individual screw-and-nut type hip joint and proceed to the complex movements of the entire insect attaining a defence position. This posture is achieved by a specific cascade of movements: Head and legs interlock mutually and with specific features of thorax and the first abdominal ventrite, presumably to increase the mechanical stability of the beetle and to maintain the defence position with minimal muscle activity. The deterministic interaction of accurately fitting body parts follows a defined sequence, which resembles a piece of engineering. PMID:25029366

The Mysteries and Curiosities of Mars: A Tour of Unusual and Unexplained Terrains

NASA Astrophysics Data System (ADS)

Kerber, L.

2017-12-01

The large amount of data available from orbiting satellites around Mars has provided a wealth of information about the Martian surface and geological history. The published literature tends to focus on regions of Mars for which there are ready explanations; however, many regions of Mars remain mysterious. In this contribution, we present some of the strangest and least explained terrains on Mars: The Taffy Terrain: This complex terrain, consisting of swirling layers with variably sized bands, is present mostly at the bottom of Hellas Basin, but versions of it can also be found on the floor of Melas Chasma and in the Medusae Fossae Formation near Apollinaris Sulci. While little has been written about the taffy terrain, hypotheses include "glacial features" and salt domes. The taffy terrain bears some resemblance to submarine salt domes in the Gulf of Mexico, glacial deposits with mixed ash and ice in Iceland, or chalk formations in Egypt's White Desert. The Fishscale Terrain: At the northern edge of Lucus Planum, the friable Medusae Fossae Formation transitions into a chaos-like terrain with hundreds of mesas forming a pattern like the scales of a fish. While chaos terrains are mysterious in general, this morphologically fresh, near-equatorial chaos is especially unusual. Polygonal Ridges in Gordii Dorsum: Also a part of the Medusae Fossae Formation, the ridges in Gordii Dorsum represent a negative image of the fishscale terrain—a intricate lattice of slender black ridges. These are thought to form via the embayment of the fishscale terrain with lava and the subsequent erosion of the original mesas. Horseshoe Features: These geomorphological features look like inverted barchan dunes, but they are actually pits eroded into the surface of the Medusae Fossae Formation. Channels surrounding Elysium Mons: These channel systems are among the most complex on Mars, but they appear on a young Amazonian lava surface. The channels cut through topography, anastomose, and create streamlined islands. Strange flows around cones: Some rootless cones in Cerberus Palus have unusual flows coming out of them. Possible hypotheses include lava or mudflows. Sinus Meridiani: This region is host to arcuate ridge lattices, circular mesas with concentric patterns, and straight, subparallel ridges, similar to other ridges found near the South Pole.

Anomalous Lower Crustal and Surface Features as a Result of Plume-induced Continental Break-up: Inferences from Numerical Models

NASA Astrophysics Data System (ADS)

Beniest, A.; Koptev, A.; Leroy, S. D.

2016-12-01

Anomalous features along the South American and African rifted margins at depth and at the surface have been recognised with gravity and magnetic modelling. They include high velocity/high density bodies at lower crustal level and topography variations that are usually interpreted as aborted rifts. We present fully-coupled lithosphere-scale numerical models that permit us to explain both features in a relatively simple framework of an interaction between rheologically stratified continental lithosphere and an active mantle plume. We used 2D and 3D numerical models to investigate the impact of thermo-rheological structure of the continental lithosphere and initial plume position on continental rifting and breakup processes. Based on the results of our 2D experiments, three main types of continental break-up are revealed: A) mantle plume-induced break-up, directly located above the centre of the mantle anomaly, B) mantle plume-induced break-up, 50 to 250 km displaced from the initial plume location and C) self-induced break-up due to convection and/or slab-subduction/delamination, considerably shifted (300 to 800 km) from the initial plume position. With our 3D, laterally homogenous initial setup, we show that a complex system, with the axis of continental break-up 100's of km's shifted from the original plume location, can arise spontaneously from simple and perfectly symmetric preliminary settings. Our modelling demonstrates that fragments of a laterally migrating plume head become glued to the base of the lithosphere and remain at both sides of the newly-formed oceanic basin after continental break-up. Underplated plume material soldered into lower parts of lithosphere can be interpreted as the high-velocity/high density magmatic bodies at lower crustal levels. In the very early stages of rifting, first impingement of the vertically upwelled mantle plume to the lithospheric base leads to surface topographic variations. Given the shifted position of the final spreading centre with respect to initial plume position, these topographic variations resemble aborted rifts that are observed on passive margins. Lastly, after continuous extension and transition to the spreading state, strain rate relocalizations develop that can be interpreted as ridge jumps that are commonly observed in nature.

Chlamydomonas sajao nov. sp. (Chlorophyta, Volvocales)

NASA Astrophysics Data System (ADS)

Lewin, Ralph A.

1984-06-01

A new species of Chlamydomonas, namely, C. sajao nov. sp. of the Volvocales, Chlorophyta was isolated from a duckweed growing near a ricefield in the vicinity of Guangzhou, China. This interesting unicellular green alga, similar to C. mexicana from Mexico, secretes quantities of extracellular mucilaginous polysaccharides, and may be employed in improving soil quality. The new species resembles C. waldenburgensis Moewus in most characteristics but differs in three important features.

The yeast genus Tortispora gen. nov., description of Tortispora ganteri sp. nov., Tortispora mauiana f.a., sp. nov., Tortispora agaves f.a., sp. nov., Tortispora sangerardii f.a., sp. nov.,...

USDA-ARS?s Scientific Manuscript database

We describe the yeast genus Tortispora gen. nov., an early diverging lineage in the Saccharomycetales that features the formation of helical ascospores. The genus is based on 16 strains resembling Candida caseinolytica that were isolated from necrotic plant tissue in warm regions of the New World. B...

Cytological features of the Warthin-like variant of salivary mucoepidermoid carcinoma.

PubMed

Hang, Jen-Fan; Shum, Chung H; Ali, Syed Z; Bishop, Justin A

2017-12-01

Warthin-like mucoepidermoid carcinoma is a recently proposed variant of musoepidermoid carcinoma. Histologically, it is characterized by its close resemblance to Warthin tumor, including dense lymphocytic infiltration, flattened intermediate epithelium resembling squamous metaplasia, and cystic change. Given its histologic similarity to Warthin tumor, confirmatory testing for MAML2 rearrangement is often required for this diagnosis. Here we present the first cytologic reports of two 53-year-old female patients with parotid masses. In both cases, the fine needle aspirations showed fragments of bland epithelium with a squamous appearance, mucinous cyst content, and focal lymphocytic background. Neither frank keratinization nor mucinous cells were identified in the smears. Fluorescence in situ hybridization (FISH) study confirmed MAML2 rearrangement on the resection specimens in both. Other cytologic differential diagnoses, including Warthin tumor with metaplasia, lymphadenoma, and lymphoepithelial cyst, were briefly discussed. © 2017 Wiley Periodicals, Inc.

Wind vs. Dust Devil Streaks

NASA Technical Reports Server (NTRS)

2004-01-01

22 February 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image presents a fine illustration of the difference between streaks made by dust devils and streaks made by wind gusts. Dust devils are usually solitary, spinning vortices. They resemble a tornado, or the swirling motion of a familiar, Tasmanian cartoon character. Wind gusts, on the other hand, can cover a larger area and affect more terrain at the same time. The dark, straight, and parallel features resembling scrape marks near the right/center of this image are thought to have been formed by a singular gust of wind, whereas the more haphazard dark streaks that crisscross the scene were formed by dozens of individual dust devils, acting at different times. This southern summer image is located in Noachis Terra near 67.0oS, 316.2oW. Sunlight illuminates the scene from the upper left; the picture covers an area 3 km (1.9 mi) wide.

Reflectance Confocal Microscopy in Lentigo Maligna.

PubMed

Gamo, R; Pampín, A; Floristán, U

2016-12-01

Lentigo maligna is the most common type of facial melanoma. Diagnosis is complicated, however, as it shares clinical and dermoscopic characteristics with other cutaneous lesions of the face. Reflectance confocal microscopy is an imaging technique that permits the visualization of characteristic features of lentigo maligna. These include a disrupted honeycomb pattern and pagetoid cells with a tendency to show folliculotropism. These cells typically have a dendritic morphology, although they may also appear as round cells measuring over 20μm with atypical nuclei. Poorly defined dermal papillae and atypical cells may be seen at the dermal-epidermal junction and can form bridges resembling mitochondrial structures. Other characteristic findings include junctional swelling with atypical cells located around the follicles, resembling caput medusae. Reflectance confocal microscopy is a very useful tool for diagnosing lentigo maligna. Copyright © 2016 AEDV. Publicado por Elsevier España, S.L.U. All rights reserved.

Colliding nuclei to colliding galaxies: Illustrations using a simple colliding liquid-drop apparatus

NASA Astrophysics Data System (ADS)

Becchetti, F. D.; Mack, S. L.; Robinson, W. R.; Ojaruega, M.

2015-10-01

A simple apparatus suitable for observing the collisions between drops of fluids of various properties is described. Typical results are shown for experiments performed by undergraduate students using various types of fluids. The collisions take place under free-fall (zero-g) conditions, with analysis employing digital video. Two specific types of collisions are examined in detail, head-on collisions and peripheral, grazing collisions. The collisions for certain fluids illustrate many types of nuclear collisions and provide useful insight into these processes, including both fusion and non-fusion outcomes, often with the formation of exotic shapes or emission of secondary fragments. Collisions of other liquids show a more chaotic behavior, often resembling galactic collisions. As expected, the Weber number associated with a specific collision impact parameter is found to be the important quantity in determining the initial outcome of these colliding systems. The features observed resemble those reported by others using more elaborate experimental techniques.

An enigmatic fossil fungus from the 410 Ma Rhynie chert that resembles Macrochytrium (Chytridiomycota) and Blastocladiella (Blastocladiomycota).

PubMed

Krings, Michael; Taylor, Thomas N; Martin, Helmut

2016-01-01

Litter layers in the Lower Devonian (~ 410 Ma) Rhynie chert were inhabited by a wide variety of saprotrophic fungi, however, only a few of these organisms have been described formally. A new microfungus, Trewinomyces annulifer gen. et sp. nov., occurs as tufts on decaying land plant axes from the Rhynie chert. The fungus consists of an intramatrical rhizoidal system and an erect extramatrical hypha (stalk) that bears a single, terminal sporangium. One or two successive rings often are present in the stalk immediately below the sporangium base. Overall morphology of T. annulifer resembles the extant genera Macrochytrium (Chytridiomycota) and Blastocladiella (Blastocladiomycota). However, the rhizoids are septate or pseudoseptate, a feature not known in extant zoosporic fungi, and thus render the systematic affinities of T. annulifer unresolved. Trewinomyces annulifer offers a rare view of the morphology of a distinctive Early Devonian saprotrophic microfungus. © 2016 by The Mycological Society of America.

Solution structure of the phosphoryl transfer complex between the cytoplasmic A domain of the mannitol transporter IIMannitol and HPr of the Escherichia coli phosphotransferase system.

PubMed

Cornilescu, Gabriel; Lee, Byeong Ryong; Cornilescu, Claudia C; Wang, Guangshun; Peterkofsky, Alan; Clore, G Marius

2002-11-01

The solution structure of the complex between the cytoplasmic A domain (IIA(Mtl)) of the mannitol transporter II(Mannitol) and the histidine-containing phosphocarrier protein (HPr) of the Escherichia coli phosphotransferase system has been solved by NMR, including the use of conjoined rigid body/torsion angle dynamics, and residual dipolar couplings, coupled with cross-validation, to permit accurate orientation of the two proteins. A convex surface on HPr, formed by helices 1 and 2, interacts with a complementary concave depression on the surface of IIA(Mtl) formed by helix 3, portions of helices 2 and 4, and beta-strands 2 and 3. The majority of intermolecular contacts are hydrophobic, with a small number of electrostatic interactions at the periphery of the interface. The active site histidines, His-15 of HPr and His-65 of IIA(Mtl), are in close spatial proximity, and a pentacoordinate phosphoryl transition state can be readily accommodated with no change in protein-protein orientation and only minimal perturbations of the backbone immediately adjacent to the histidines. Comparison with two previously solved structures of complexes of HPr with partner proteins of the phosphotransferase system, the N-terminal domain of enzyme I (EIN) and enzyme IIA(Glucose) (IIA(Glc)), reveals a number of common features despite the fact that EIN, IIA(Glc), and IIA(Mtl) bear no structural resemblance to one another. Thus, entirely different underlying structural elements can form binding surfaces for HPr that are similar in terms of both shape and residue composition. These structural comparisons illustrate the roles of surface and residue complementarity, redundancy, incremental build-up of specificity and conformational side chain plasticity in the formation of transient specific protein-protein complexes in signal transduction pathways.

Tidal and residual circulation in a semi-arid bay: Coquimbo Bay, Chile

NASA Astrophysics Data System (ADS)

Valle-Levinson, Arnoldo; Moraga, Julio; Olivares, Jorge; Blanco, José Luis

2000-11-01

Velocity profiles and time-series data were combined with conductivity-temperature-depth (CTD) casts to describe the general circulation at tidal and subtidal scales in a bay of semi-arid climate, Coquimbo Bay (˜30°S), Chile. This was the first study that used a towed acoustic Doppler current profiler (ADCP) in coastal Chilean waters and is one of the very few in semi-arid bays. The ADCP was towed for two semi-diurnal tidal cycles in early austral autumn, between March 23 and 24, 1997 along a triangular trajectory that covered most of the bay. Additional data consisted of moored current meters and CTD casts. The observations indicated the presence of a surface layer, above the pycnocline, that showed predominantly diurnal variability forced by the breeze regime and by tides. The tidal circulation in the surface layer featured amplitudes of 10 cm/s within an anticyclonic gyre that occupied most of the bay. The subtidal circulation in the surface was characterized by a pair of counter-rotating gyres. The northernmost three-fourths of the bay showed an anticyclonic gyre, and the observations over the southern fourth implied a cyclonic gyre. The subtidal anticyclonic gyre had a counterpart rotating in opposite direction within a lower layer, underneath the pycnocline. The lower layer showed semidiurnal variability in addition to diurnal variability and was insulated by the pycnocline from heat and momentum fluxes through the air-water interface. Circulations that resemble estuarine and anti-estuarine patterns were found associated with the subtidal gyres. A horizontal divergence related to a 10 cm/s near-surface outflow around Point Tortuga, to the south of the bay entrance, allowed the development of upward motion off the Point, as evidenced by the tilt of the isopycnals at the entrance to the bay.

FC colour images of dwarf planet Ceres reveal a complicated geological history

NASA Astrophysics Data System (ADS)

Nathues, A.; Hoffmann, M.; Platz, T.; Thangjam, G. S.; Cloutis, E. A.; Reddy, V.; Le Corre, L.; Li, J.-Y.; Mengel, K.; Rivkin, A.; Applin, D. M.; Schaefer, M.; Christensen, U.; Sierks, H.; Ripken, J.; Schmidt, B. E.; Hiesinger, H.; Sykes, M. V.; Sizemore, H. G.; Preusker, F.; Russell, C. T.

2016-12-01

The dwarf planet Ceres (equatorial diameter 963km) is the largest object that has remained in the main asteroid belt (Russell and Raymond, 2012), while most large bodies have been destroyed or removed by dynamical processes (Petit et al. 2001; Minton and Malhotra, 2009). Pre-Dawn investigations (McCord and Sotin, 2005; Castillo-Rogez and McCord, 2010; Castillo-Rogez et al., 2011) suggest that Ceres is a thermally evolved, but still volatile-rich body with potential geological activity, that was never completely molten, but possibly differentiated into a rocky core, an ice-rich mantle, and may contain remnant internal liquid water. Thermal alteration should contribute to producing a (dark) carbonaceous chondritic-like surface (McCord and Sotin, 2005; Castillo-Rogez and McCord, 2010; Castillo-Rogez et al., 2011; Nathues et al., 2015) containing ammoniated phyllosilicates (King et al., 1992; De Sanctis et al., 2015 and 2016). Here we show and analyse global contrast-rich colour mosaics, derived from a camera on-board Dawn at Ceres (Russell et al., 2016). Colours are unexpectedly more diverse on global scale than anticipated by Hubble Space Telescope (Li et al., 2006) and ground-based observations (Reddy et al. 2015). Dawn data led to the identification of five major colour units. The youngest units identified by crater counting, termed bright and bluish units, are exclusively found at equatorial and intermediate latitudes. We identified correlations between the distribution of the colour units, crater size, and formation age, inferring a crustal stratigraphy. Surface brightness and spectral properties are not correlated. The youngest surface features are the bright spots at crater Occator ( Ø 92km). Their colour spectra are highly consistent with the presence of carbonates while most of the remaining surface resembles modifications of various types of ordinary carbonaceous chondrites.

Rapid interactions between lexical semantic and word form analysis during word recognition in context: evidence from ERPs.

PubMed

Kim, Albert; Lai, Vicky

2012-05-01

We used ERPs to investigate the time course of interactions between lexical semantic and sublexical visual word form processing during word recognition. Participants read sentence-embedded pseudowords that orthographically resembled a contextually supported real word (e.g., "She measured the flour so she could bake a ceke…") or did not (e.g., "She measured the flour so she could bake a tont…") along with nonword consonant strings (e.g., "She measured the flour so she could bake a srdt…"). Pseudowords that resembled a contextually supported real word ("ceke") elicited an enhanced positivity at 130 msec (P130), relative to real words (e.g., "She measured the flour so she could bake a cake…"). Pseudowords that did not resemble a plausible real word ("tont") enhanced the N170 component, as did nonword consonant strings ("srdt"). The effect pattern shows that the visual word recognition system is, perhaps, counterintuitively, more rapidly sensitive to minor than to flagrant deviations from contextually predicted inputs. The findings are consistent with rapid interactions between lexical and sublexical representations during word recognition, in which rapid lexical access of a contextually supported word (CAKE) provides top-down excitation of form features ("cake"), highlighting the anomaly of an unexpected word "ceke."

Rapid tissue engineering of biomimetic human corneal limbal crypts with 3D niche architecture.

PubMed

Levis, Hannah J; Massie, Isobel; Dziasko, Marc A; Kaasi, Andreas; Daniels, Julie T

2013-11-01

Limbal epithelial stem cells are responsible for the maintenance of the human corneal epithelium and these cells reside in a specialised stem cell niche. They are located at the base of limbal crypts, in a physically protected microenvironment in close proximity to a variety of neighbouring niche cells. Design and recreation of elements of various stem cell niches have allowed researchers to simplify aspects of these complex microenvironments for further study in vitro. We have developed a method to rapidly and reproducibly create bioengineered limbal crypts (BLCs) in a collagen construct using a simple one-step method. Liquid is removed from collagen hydrogels using hydrophilic porous absorbers (HPAs) that have custom moulded micro-ridges on the base. The resulting topography on the surface of the thin collagen constructs resembles the dimensions of the stromal crypts of the human limbus. Human limbal epithelial cells seeded onto the surface of the constructs populate these BLCs and form numerous layers with a high proportion of the cells lining the crypts expressing putative stem cell marker, p63α. The HPAs are produced using a moulding process that is flexible and can be adapted depending on the requirements of the end user. Creation of defined topographical features using this process could be applicable to numerous tissue-engineering applications where varied 3-dimensional niche architectures are required. Copyright © 2013 Elsevier Ltd. All rights reserved.

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

Osipiuk, J.; Gornicki, P.; Maj, L.

The structure of the YlxR protein of unknown function from Streptococcus pneumonia was determined to 1.35 Angstroms. YlxR is expressed from the nusA/infB operon in bacteria and belongs to a small protein family (COG2740) that shares a conserved sequence motif GRGA(Y/W). The family shows no significant amino-acid sequence similarity with other proteins. Three-wavelength diffraction MAD data were collected to 1.7 Angstroms from orthorhombic crystals using synchrotron radiation and the structure was determined using a semi-automated approach. The YlxR structure resembles a two-layer {alpha}/{beta} sandwich with the overall shape of a cylinder and shows no structural homology to proteins of knownmore » structure. Structural analysis revealed that the YlxR structure represents a new protein fold that belongs to the {alpha}-{beta} plait superfamily. The distribution of the electrostatic surface potential shows a large positively charged patch on one side of the protein, a feature often found in nucleic acid-binding proteins. Three sulfate ions bind to this positively charged surface. Analysis of potential binding sites uncovered several substantial clefts, with the largest spanning 3/4 of the protein. A similar distribution of binding sites and a large sharply bent cleft are observed in RNA-binding proteins that are unrelated in sequence and structure. It is proposed that YlxR is an RNA-binding protein.« less

[Transitional cell carcinoma of the ovary. Morphological and clinical features].

PubMed

Kommoss, F; Kommoss, S; Eichhorn, J; Schmidt, D

2007-05-01

Transitional cell carcinoma of the ovary (TCC-O) is a less common type of malignant surface epithelial-stromal tumor of the ovary, still with uncertain incidence. Histologically, TCC-O resembles urothelial carcinoma of the urinary system, and by definition does not contain a Brenner tumor component. TCC-O may not be a bona fide urothelial neoplasm, however, but rather a lesion of the Müllerian type derived from the ovarian surface epithelium. This notion is supported by the existence of mixed tumors consisting of TCC-O and other histological types of ovarian carcinoma, as well as the observation that TCC-O has a Müllerian type but not a urothelial-like immunohistochemical profile. Besides metastatic urothelial carcinoma of the urinary tract, the other types of ovarian carcinoma, as well as sex cord-stromal tumors such as adult granulosa cell tumors, have to be considered in the differential diagnosis of TCC-O. A recent analysis of a large series of advanced ovarian carcinomas treated by radical surgery and postoperative chemotherapy confirms studies that had suggested that TCC-O has a better prognosis (with current treatment) than that of the other histological types of ovarian carcinoma. Further studies applying standardized histopathological criteria are needed to clarify the true incidence and behavior of TCC-O. In addition, it is important to study the biological and molecular background of this apparently less aggressive phenotype.

Submicrostructure and typing of female genital condylomata.

PubMed

He, Y C; Shen, L S; Xie, Z J; Yang, C L; Li, H; Zheng, Y; Zhu, G C; Zhao, S Z; Wang, C X; Zhang, J H

1993-04-01

Thirty biopsies from female genital condylomata were examined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) to study structural characteristics and typing of condylomata. It was found that cytoplasmic clearing was marked in acuminate condylomata, diffuse interstitial and epithelial proliferation in nodular condylomata (flat condylomata), and invagination of the lesions into the interstitial tissue or glandular ducts in endophytic condylomata. In nodular condylomata, SEM also showed some structural features similar to those of intra-epithelial neoplasia. Microridges on the surface of squamous cells had villiform of granular changes. On the surface of a percentage of squamous or columnar cells, there were holes with a diameter of about 3 to 5 microns. A number of giant cells were seen among other cells. The cervical squamatization zone contained groups of special cells covered with dense microvilli. TEM of nodular condylomata revealed some pictures resembling active proliferation of tumor cells, such as enlarged or irregular nuclei (large N/C ratio), evaginated or invaginated nuclear membranes, condensed chromatin attached to the inner part of the nuclear membrane, transparent nucleoplasm, and frequent nucleosomes and karyokinesis. Virus particles with the morphological characteristics of HPV (naked hexagon-like particles with an average diameter of 45-50 nm) were seen in some nuclei with markedly condensed chromatin. It is suggested that HPV-induced genital condylomata, especially nodular one (flat condylomata), entail a potential progression to malignancy.

Streptococcus pneumonia YlxR at 1.35 A shows a putative new fold.

PubMed

Osipiuk, J; Górnicki, P; Maj, L; Dementieva, I; Laskowski, R; Joachimiak, A

2001-11-01

The structure of the YlxR protein of unknown function from Streptococcus pneumonia was determined to 1.35 A. YlxR is expressed from the nusA/infB operon in bacteria and belongs to a small protein family (COG2740) that shares a conserved sequence motif GRGA(Y/W). The family shows no significant amino-acid sequence similarity with other proteins. Three-wavelength diffraction MAD data were collected to 1.7 A from orthorhombic crystals using synchrotron radiation and the structure was determined using a semi-automated approach. The YlxR structure resembles a two-layer alpha/beta sandwich with the overall shape of a cylinder and shows no structural homology to proteins of known structure. Structural analysis revealed that the YlxR structure represents a new protein fold that belongs to the alpha-beta plait superfamily. The distribution of the electrostatic surface potential shows a large positively charged patch on one side of the protein, a feature often found in nucleic acid-binding proteins. Three sulfate ions bind to this positively charged surface. Analysis of potential binding sites uncovered several substantial clefts, with the largest spanning 3/4 of the protein. A similar distribution of binding sites and a large sharply bent cleft are observed in RNA-binding proteins that are unrelated in sequence and structure. It is proposed that YlxR is an RNA-binding protein.

Short-wavelength infrared (1.3-2.6 μm) observations of the nucleus of Comet 19P/Borrelly

USGS Publications Warehouse

Soderblom, L.A.; Britt, D.T.; Brown, R.H.; Buratti, B.J.; Kirk, R.L.; Owen, T.C.; Yelle, R.V.

2004-01-01

During the last two minutes before closest approach of Deep Space 1 to Comet 19P/Borrelly, a long exposure was made with the short-wavelength infrared (SWIR) imaging spectrometer. The observation yielded 46 spectra covering 1.3–2.6 μm; the footprint of each spectrum was ∼160 m × width of the nucleus. Borrelly's highly variegated and extremely dark 8-km-long nucleus exhibits a strong red slope in its short-wavelength infrared reflection spectrum. This slope is equivalent to J–K and H–K colors of ∼0.82 and ∼0.43, respectively. Between 2.3–2.6 μm thermal emission is clearly detectable in most of the spectra. These data show the nucleus surface to be hot and dry; no trace of H2O ice was detected. The surface temperature ranged continuously across the nucleus from ⩽300 K near the terminator to a maximum of ∼340 K, the expected sub-solar equilibrium temperature for a slowly rotating body. A single absorption band at ∼2.39 μm is quite evident in all of the spectra and resembles features seen in nitrogen-bearing organic molecules that are reasonable candidates for compositional components of cometary nuclei. However as of yet the source of this band is unknown.

Microbial shaping of wrinkle structures in siliciclastic deposits

NASA Astrophysics Data System (ADS)

Bosak, T.; Mariotti, G.; Pruss, S. B.; Perron, J.; O'Grady, M.

2013-12-01

Wrinkle structures are millimeter- to centimeter-scale elongated or reticulate sedimentary structures that resemble symmetric ripples. Sharp-crested and flat-topped wrinkle structures up to 1 cm wide occur on numerous bedding planes in the Neoproterozoic and Cambrian, as well as in some Archean and Phanerozoic siliciclastic deposits. Because similar, but unlithified structures occur in some modern, microbially-colonized sands, wrinkle structures are typically interpreted as microbially induced sedimentary structures. However, it is unclear if physical processes, such as the motion of suspended sand grains, can produce similar features in sand even before microbial colonization. We introduced mat fragments to the surface of silica sand in wave tanks and generated sharp-crested, flat-topped and pitted wrinkle structures. The abrasion of the sandy surface by rolling, low density, millimeter-size fragments of microbial mats produces wrinkle structures at extremely weak orbital velocities that cannot move sand grains in the absence of light particles. Wrinkle structures form in a few hours and can become colonized by microbial mats within weeks. Thus, wrinkle structures are patterns formed by microbially mediated sand motion at low orbital velocities in the absence of bioturbation. Once formed, wrinkle structures can be colonized and stabilized by microbial mats, but the shape of these mats does not dictate the shape of wrinkle structures. These experiments bolster the interpretation of wrinkle structures as morphological signatures of organic particles and early life in Archean and Proterozoic siliciclastic deposits.

New observations of (4179) Toutatis from the Chang'e-2 flyby mission and future Chinese missions to asteroids

NASA Astrophysics Data System (ADS)

Ji, J.

2014-07-01

Primitive asteroids are remnant building blocks in the Solar System formation. They provide key clues for us to reach in-depth understanding of the process of planetary formation, the complex environment of early Solar nebula, and even the occurrence of life on the Earth. On 13 December 2012, Chang'e-2 completed a successful flyby of the near-Earth asteroid (4179) Toutatis at a closest distance of 770 meters from the asteroid's surface. The observations show that Toutatis has an irregular surface and its shape resembles a ginger-root with a smaller lobe (head) and a larger lobe (body). Such bifurcated configuration is indicative of a contact binary origin for Toutatis. In addition, the images with a 3-m resolution or higher provide a number of new discoveries about this asteroid, such as an 800-meter basin at the end of the large lobe, a sharply perpendicular silhouette near the neck region, and direct evidence of boulders and regolith, indicating that Toutatis is probably a rubble-pile asteroid. The Chang'e-2 observations have provided significant new insights into the geological features and the formation and evolution of this asteroid. Moreover, a conceptual introduction to future Chinese missions to asteroids, such as the major scientific objectives, scientific payloads, and potential targets, will be briefly given. The proposed mission will benefit a lot from potential international collaboration in the future.

Lunar sample 14425 - Characterization and resemblance to high-magnesium microtektites

NASA Technical Reports Server (NTRS)

Berliner, L.; Fujii, H.

1985-01-01

Measurements by energy-dispersive X-ray analysis of the surface of lunar sample 14425, a large glass bead, yield a noritic composition enriched in aluminum and magnesium and, as compared with other norites, depleted in iron and especially calcium. The sample is close in composition to the most basic microtektites. Spherical inclusions of nickel-iron, flattened where they protrude, are found to be enriched in sulfur and phosphorus, at least at the surface. The inclusions form approximately 1 percent of the volume.

Differential binding of neutralizing and non-neutralizing antibodies to native-like soluble HIV-1 Env trimers, uncleaved Env proteins, and monomeric subunits

PubMed Central

2014-01-01

Background The trimeric envelope glycoproteins (Env) on the surface of HIV-1 virions are the targets for neutralizing antibodies (NAbs). No candidate HIV-1 immunogen has yet induced potent, broadly active NAbs (bNAbs). Part of the explanation may be that previously tested Env proteins inadequately mimic the functional, native Env complex. Trimerization and the proteolytic processing of Env precursors into gp120 and gp41 profoundly alter antigenicity, but soluble cleaved trimers are too unstable to serve as immunogens. By introducing stabilizing mutations (SOSIP), we constructed soluble, cleaved Env trimers derived from the HIV-1 subtype A isolate BG505 that resemble native Env spikes on virions both structurally and antigenically. Results We used surface plasmon resonance (SPR) to quantify antibody binding to different forms of BG505 Env: the proteolytically cleaved SOSIP.664 trimers, cleaved gp120-gp41ECTO protomers, and gp120 monomers. Non-NAbs to the CD4-binding site bound only marginally to the trimers but equally well to gp120-gp41ECTO protomers and gp120 monomers, whereas the bNAb VRC01, directed to the CD4bs, bound to all three forms. In contrast, bNAbs to V1V2 glycan-dependent epitopes bound preferentially (PG9 and PG16) or exclusively (PGT145) to trimers. We also explored the antigenic consequences of three different features of SOSIP.664 gp140 trimers: the engineered inter-subunit disulfide bond, the trimer-stabilizing I559P change in gp41ECTO, and proteolytic cleavage at the gp120-gp41ECTO junction. Each of these three features incrementally promoted native-like trimer antigenicity. We compared Fab and IgG versions of bNAbs and validated a bivalent model of IgG binding. The NAbs showed widely divergent binding kinetics and degrees of binding to native-like BG505 SOSIP.664. High off-rate constants and low stoichiometric estimates of NAb binding were associated with large amounts of residual infectivity after NAb neutralization of the corresponding BG505.T332N pseudovirus. Conclusions The antigenicity and structural integrity of cleaved BG505 SOSIP.664 trimers render these proteins good mimics of functional Env spikes on virions. In contrast, uncleaved gp140s antigenically resemble individual gp120-gp41ECTO protomers and gp120 monomers, but not native trimers. Although NAb binding to functional trimers may thus be both necessary and sufficient for neutralization, the kinetics and stoichiometry of the interaction influence the neutralizing efficacy of individual NAbs. PMID:24884783

Pit membranes of Ephedra resemble gymnosperms more than angiosperms

Treesearch

Roland Dute; Lauren Bowen; Sarah Schier; Alexa Vevon; Troy Best; Maria Auad; Thomas Elder; Pauline Bouche; Steven Jansen

2014-01-01

Bordered pit pairs of Ephedra species were characterized using different types of microscopy. Pit membranes contained tori that did not stain for lignin. SEM and AFM views of the torus surface showed no plasmodesmatal openings, but branched, secondary plasmodesmata were occasionally noted using TEM in conjunction with ultrathin sections. The margo consisted of radial...

The Northeast Cyanobacteria Monitoring Program: One Program, Three Opportunities for You To Get Involved!

EPA Science Inventory

If you ever have noticed a waterbody with a layer of green scum coating its surface or a slick green film resembling a paint spill, you likely have witnessed a cyanobacteria bloom. Cyanobacteria, sometimes referred to as blue-green algae, are tiny organisms found naturally in aqu...

Fermiology and electron dynamics of trilayer nickelate La 4Ni 3O 10

DOE PAGES

Li, Haoxiang; Zhou, Xiaoqing; Nummy, Thomas; ...

2017-09-26

Layered nickelates have the potential for exotic physics similar to high T C superconducting cuprates as they have similar crystal structures and these transition metals are neighbors in the periodic table. Here we present an angle-resolved photoemission spectroscopy (ARPES) study of the trilayer nickelate La 4Ni 3O 10 revealing its electronic structure and correlations, finding strong resemblances to the cuprates as well as a few key differences. We find a large hole Fermi surface that closely resembles the Fermi surface of optimally hole-doped cuprates, including its d x2-y2 orbital character, hole filling level, and strength of electronic correlations. However, inmore » contrast to cuprates, La 4Ni 3O 10 has no pseudogap in the d x2-y2 band, while it has an extra band of principally d 3z2-r2 orbital character, which presents a low temperature energy gap. Furthermore, these aspects drive the nickelate physics, with the differences from the cuprate electronic structure potentially shedding light on the origin of superconductivity in the cuprates.« less

Mullerian papilloma-like proliferation arising in cystic pelvic endosalpingiosis.

PubMed

McCluggage, W Glenn; O'Rourke, Declan; McElhenney, Clodagh; Crooks, Michael

2002-09-01

This report describes an unusual epithelial proliferation occurring in pelvic cystic endosalpingiosis. A cyst mass lined by a layer of ciliated epithelial cells involved the posterior surface of the cervix and vagina. The epithelial proliferation within the wall resembled a mullerian papilloma with fibrous and fibrovascular cores lined by bland cuboidal epithelial cells. Other areas had a microglandular growth pattern resembling cervical microglandular hyperplasia, and focally there was a solid growth pattern. Foci of typical endosalpingiosis involved the surface of both ovaries and pelvic soft tissues. The cystic lesion recurred after partial cystectomy and drainage and was followed up radiologically and with periodic fine-needle aspiration. Part of the wall of the cyst removed 11 years after the original surgery showed an identical epithelial proliferation. MIB1 staining showed a proliferation index of less than 5%, contrasting with the higher proliferation index of a typical serous borderline tumor. The differential diagnosis is discussed. As far as we are aware, this is the first report of such a benign epithelial proliferation involving cystic endosalpingiosis. Copyright 2002, Elsevier Science (USA). All rights reserved.

Quantitative three-dimensional shape analysis of the proximal hallucial metatarsal articular surface in Homo, Pan, Gorilla, and Hylobates.

PubMed

Proctor, Daniel J; Broadfield, Douglas; Proctor, Kristopher

2008-02-01

Multidimensional morphometrics is used to compare the proximal articular surface of the first metatarsal between Homo, Pan, Gorilla, Hylobates, and the hominin fossils A.L. 333-54 (A. afarensis), SKX 5017 (P. robustus), and OH 8 (H. habilis). Statistically significant differences in articular surface morphology exist between H. sapiens and the apes, and between ape groups. Ape groups are characterized by greater surface depth, an obliquely curved articular surface through the dorso-lateral and medio-plantar regions, and a wider medio-lateral surface relative to the dorso-plantar height. The OH 8 articular surface is indistinguishable from H. sapiens, while A.L. 333-54 and SKX 5017 more closely resemble the apes. P. robustus and A. afarensis exhibit ape-like oblique curvature of the articular surface. Copyright 2007 Wiley-Liss, Inc.

Leiomyomatous hamartoma of the incisive papilla.

PubMed

Corrêa, L; Lotufo, M; Martins, M T; Sugaya, N; de Sousa, S C

2001-01-01

A case of unusual hamartoma in a six-year-old otherwise healthy Brazilian girl is reported, with emphasis on histological and immunohistochemical features. A mass observed in the incisive papilla was detected whose appearance was similar to congenital epulis or fibroma. Histological findings showed interlacing fascicles of large spindle cells resembling smooth muscle cells. Immunohistochemical staining for desmin and for smooth-muscle actin was positive. The histological diagnosis was leiomyomatous hamartoma, based on clinical and microscopic observations.

A Z-axis recumbent rotating device for use in parabolic flight

NASA Technical Reports Server (NTRS)

Graybiel, A.; Miller, E. F., II

1976-01-01

A prototype apparatus for exposing persons to rotation about their Z-axis in parabolic flight is described. Although it resembles earth-horizontal axis devices, added features are its strength and portability, and the fiber glass 'couch' with adjustable elements providing support and restraint. Even under ground-based conditions, this device provides unique opportunities for investigations involving not only canalicular and macular mechanoreceptors, but also touch, pressure, and kinesthetic receptor systems.

Primary Tumours of the Fallopian Tube

PubMed Central

Ross, Winifred M.

1967-01-01

Nine patients with primary tumour of the fallopian tube were seen at the Royal Marsden Hospital and Chelsea Hospital for Women, London. All the tumours except one were adenocarcinomas. Histologically, the exception resembled an adenomatoid tumour, but was clinically malignant and had some features of a hemangiopericytoma. Postoperative irradiation did not increase survival. The only five-year survivor was a patient who received radiation therapy for a late local recurrence. ImagesFig. 1Fig. 2 PMID:5334754

A Need to Know: The Role of Air Force Reconnaissance in War Planning, 1945 - 1953

DTIC Science & Technology

1991-01-01

plan BROILER , the Joint Chiefs of Staff continued their reliance on strategic air war, but the doctrinal basis for the plans shifted from precision... BROILER . In some respects BROILER resembled the PINCHER plans: the United States assumed an accidental outbreak of war, o-verwhelming Soviet superiority...assessment, BROILER relied heavily on atomic bombs. In other words, instead of a strategic campaign featuring conventional bombardment augmented by a few

Psoriasiform keratosis - case report.

PubMed

Pires, Carla Andréa Avelar; Sousa, Brena Andrade de; Nascimento, Carla do Socorro Silva do; Moutinho, Ana Thais Machado; Miranda, Mario Fernando Ribeiro de; Carneiro, Francisca Regina Oliveira

2014-01-01

Psoriasiform Keratosis is a rare clinic entity. The etiopathogenesis remains unknown and the disease is characterized by a solitary, scaly or keratotic papule, or plaque mainly located on the extremities. Histopathological features closely resemble those of psoriasis. We report the case of a 70-year-old woman presenting a solitary and asymptomatic keratotic plaque, located on the back of the left leg, unresponsive to topical corticosteroids. We performed an excisional biopsy and histopathology was consistent with psoriasiform keratosis.

Zygomatic osteoma with atypical heterogeneity in a dog.

PubMed

Johnson, K A; Cooley, A J; Darien, D L

1996-02-01

An osteoma of the zygomatic bone in a young dog is described. It had large, centralized radiolucent regions consisting of fatty bone marrow and sparse trabeculae. A discrete, proliferative nodule within the osteoma consisted of closely-packed woven bone trabeculae and pleomorphic osteoblasts associated with haphazard osteoid deposits, resembling osteosarcoma-like change. These heterogeneous structural features were at variance with more classic reports of osteoma, which usually describe a uniform cancellous or cortical bone architecture.

Where are the dolphins?

PubMed

Cohen, J; Stewart, I

2001-02-22

Interest in extraterrestrial life has tended to focus on a search for extrasolar planets similar to the Earth. But what of forms of intelligent life that are very different from those found on Earth? Some features of life will not be peculiar to our planet, and alien life will resemble ours in such universals. But if intelligent, non-humanoid aliens exist, where might they be? Would they wish to visit Earth and would we know if they did?

Spectroscopic Confirmation of Young Planetary-mass Companions on Wide Orbits

NASA Astrophysics Data System (ADS)

Bowler, Brendan P.; Liu, Michael C.; Kraus, Adam L.; Mann, Andrew W.

2014-03-01

We present moderate-resolution (R ~ 4000-5000) near-infrared integral field spectroscopy of the young (1-5 Myr) 6-14 M Jup companions ROXs 42B b and FW Tau b obtained with Keck/OSIRIS and Gemini-North/NIFS. The spectrum of ROXs 42B b exhibits clear signs of low surface gravity common to young L dwarfs, confirming its extreme youth, cool temperature, and low mass. Overall, it closely resembles the free-floating 4-7 M Jup L-type Taurus member 2MASS J04373705+2331080. The companion to FW Tau AB is more enigmatic. Our optical and near-infrared spectra show strong evidence of outflow activity and disk accretion in the form of line emission from [S II], [O I], Hα, Ca II, [Fe II], Paβ, and H2. The molecular hydrogen emission is spatially resolved as a single lobe that stretches ≈0.''1 (15 AU). Although the extended emission is not kinematically resolved in our data, its morphology resembles shock-excited H2 jets primarily seen in young Class 0 and Class I sources. The near-infrared continuum of FW Tau b is mostly flat and lacks the deep absorption features expected for a cool, late-type object. This may be a result of accretion-induced veiling, especially in light of its strong and sustained Hα emission (EW(Hα) >~ 290 Å). Alternatively, FW Tau b may be a slightly warmer (M5-M8) accreting low-mass star or brown dwarf (0.03-0.15 M ⊙) with an edge-on disk. Regardless, its young evolutionary stage is in stark contrast to its Class III host FW Tau AB, indicating a more rapid disk clearing timescale for the host binary system than for its wide companion. Finally, we present near-infrared spectra of the young (~2-10 Myr) low-mass (12-15 M Jup) companions GSC 6214-210 B and SR 12 C and find they best resemble low-gravity M9.5 and M9 substellar templates. Some of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation.

EMBLA 2002: an Optical and Ground Survey in Hessdalen

NASA Astrophysics Data System (ADS)

Teodorani, M.; Nobili, G.

2002-10-01

A two-weeks scientific expedition to Hessdalen, aimed at investigating on field mysterious atmospheric light-phenomena, was carried out in August 2002 by the physics section of an italian team of scientists. Results are presented and discussed. Photometric analysis shows that the light-phenomenon is able to produce a luminous power of up-to 100 kW. A 3-D analysis of photo frames shows that the luminous phenomenon doesn't resemble canonical plasma features (a sharply gaussian PSF) unless the light phenomenon is caused by one recently discovered natural light-ball of BL type whose light-distribution (PSF) might be able to simulate an uniformly illuminated solid. A comparison of the light-distribution in different time-sequential frames shows that apparent slightly exponential wings of the PSF features are probably due to variations of atmospheric turbulence and transparency and not to intrinsic properties. Maximum phases of luminosity of the radiating surface are demonstrated to be due to the sudden apparition of a cluster of co-existing light-balls at constant temperature, while the inflation of light-balls is ruled out. Spectra show no resolved lines but a three-peaked feature which might be attributed both to some kind of artificial illumination system and to a mixture of many blended lines due to several chemical elements (more possibly: silicon). The results of a lab analysis of ground samples shows that some powder which was collected near a river contains an anomalous iron sphere of micrometric dimensions. A biophysical research-proposal aimed at studying the relation between the EM field produced by the phenomenon and the electrical activity of the human body is also presented. On the basis of this third explorative experience, the importance of having at disposal a sophisticated opto-electronic portable station (missing at present) is stressed for the future.

Vicariance biogeography of the open-ocean Pacific

NASA Astrophysics Data System (ADS)

White, Brian N.

The first cladogram to treat oceanic water masses as distinct geographic units presents a ‘hydrotectonic’ history of Pacific surface water masses. It is used to test the idea that the oceanographic subdivision of the surface waters of the Pacific Basin into separate water masses shaped pelagic biogeographic patterns in much the same way that the tectonic fragmentation of Pangea influenced biogeographic patterns on land. The historical water-mass relationships depicted by the surface water-mass cladogram resemble modern pelagic biogeographic regions. The prediction that the cladistic phylogenies of monophyletic groups having allopatric taxa in three or more surface water masses will be consistent with the topology of the surface water-mass cladogram is met by the pelagic fish genera Stomias and Evermanella.

MSSA de-noising of horizon time structure to improve the curvature attribute analysis

NASA Astrophysics Data System (ADS)

Tiwari, R. K.; Rekapalli, R.; Vedanti, N.

2017-12-01

Although the seismic attributes are useful for identifying sub-surface structural features like faults, fractures, lineaments and sharp stratigraphy etc., the different kinds of noises arising from unknown physical sources during the data acquisition and processing creates acute problems in physical interpretation of complex crustal structures. Hence, we propose to study effect of noise on curvature attribute analysis of seismic time structure data. We propose here Multichannel Singular Spectrum Analysis (MSSA) de-noising algorithm as a pre filtering scheme to reduce effect of noise. To demonstrate the procedure, first, we compute the most positive and negative curvature on a synthetic time structure with surface features resembling anticlines, synclines and faults and then adding the known percentage of noise. We noticed that the curvatures estimated from the noisy data reveal considerable deviations from the curvature of pure synthetic data. This suggests that there is a strong impact of noise on the curvature estimates. Further, we have employed 2D median filter and MSSA methods to filter the noisy time structure and then computed the curvatures. The comparisons of curvatures estimated from de-noised data suggest that the results obtained from MSSA de-noised data match well with the curvatures of pure synthetic data. Finally, we present an example of real data analysis from Utsira Top (UT) horizon of Southern Viking Graben, Norway to identify the time-lapse changes in UT horizon after CO2 injection. We applied the MSSA de-noising algorithm on UT horizon time structure and amplitude data of pre and post CO2 injection. Our analyses suggest modest but clearly visible, structural changes in the UT horizon after CO2 injection at a few locations, which seem to be associated with the locations of change in seismic amplitudes. Thus, the results from both the synthetic and real field data suggest that the MSSA based de-noising algorithm is robust for filtering the horizon time structures for accurate curvature attributes analysis and better interpretation of structural changes in geological features. Key Words: Curvature attributes, MSSA, Seismic Horizon, 2D-median filter, Utsira Horizon.

Parallel approaches to composite production: interfaces that behave contrary to expectation.

PubMed

Frowd, Charlie D; Bruce, Vicki; Ness, Hayley; Bowie, Leslie; Paterson, Jenny; Thomson-Bogner, Claire; McIntyre, Alexander; Hancock, Peter J B

2007-04-01

This paper examines two facial composite systems that present multiple faces during construction to more closely resemble natural face processing. A 'parallel' version of PRO-fit was evaluated, which presents facial features in sets of six or twelve, and EvoFIT, a system in development, which contains a holistic face model and an evolutionary interface. The PRO-fit parallel interface turned out not to be quite as good as the 'serial' version as it appeared to interfere with holistic face processing. Composites from EvoFIT were named almost three times better than PRO-fit, but a benefit emerged under feature encoding, suggesting that recall has a greater role for EvoFIT than was previously thought. In general, an advantage was found for feature encoding, replicating a previous finding in this area, and also for a novel 'holistic' interview.

Camouflaging in a Complex Environment—Octopuses Use Specific Features of Their Surroundings for Background Matching

PubMed Central

Josef, Noam; Amodio, Piero; Fiorito, Graziano; Shashar, Nadav

2012-01-01

Living under intense predation pressure, octopuses evolved an effective and impressive camouflaging ability that exploits features of their surroundings to enable them to “blend in.” To achieve such background matching, an animal may use general resemblance and reproduce characteristics of its entire surroundings, or it may imitate a specific object in its immediate environment. Using image analysis algorithms, we examined correlations between octopuses and their backgrounds. Field experiments show that when camouflaging, Octopus cyanea and O. vulgaris base their body patterns on selected features of nearby objects rather than attempting to match a large field of view. Such an approach enables the octopus to camouflage in partly occluded environments and to solve the problem of differences in appearance as a function of the viewing inclination of the observer. PMID:22649542

Mechanically expandable annular seal

DOEpatents

Gilmore, R.F.

1983-07-19

A mechanically expandable annular reusable seal assembly to form an annular hermetic barrier between two stationary, parallel, and planar containment surfaces is described. A rotatable ring, attached to the first surface, has ring wedges resembling the saw-tooth array of a hole saw. Matching seal wedges are slidably attached to the ring wedges and have their motion restricted to be perpendicular to the second surface. Each seal wedge has a face parallel to the second surface. An annular elastomer seal has a central annular region attached to the seal wedges' parallel faces and has its inner and outer circumferences attached to the first surface. A rotation of the ring extends the elastomer seal's central region perpendicularly towards the second surface to create the fluid tight barrier. A counter rotation removes the barrier. 6 figs.

Disordered quivers and cold horizons

DOE PAGES

Anninos, Dionysios; Anous, Tarek; Denef, Frederik

2016-12-15

We analyze the low temperature structure of a supersymmetric quiver quantum mechanics with randomized superpotential coefficients, treating them as quenched disorder. These theories describe features of the low energy dynamics of wrapped branes, which in large number backreact into extremal black holes. We show that the low temperature theory, in the limit of a large number of bifundamentals, exhibits a time reparametrization symmetry as well as a specific heat linear in the temperature. Both these features resemble the behavior of black hole horizons in the zero temperature limit. We demonstrate similarities between the low temperature physics of the random quivermore » model and a theory of large N free fermions with random masses.« less

The motor and cognitive features of Parkinson's disease in patients with concurrent Gaucher disease over 2 years: a case series.

PubMed

Collins, Lucy M; Williams-Gray, Caroline H; Morris, Elizabeth; Deegan, Patrick; Cox, Timothy M; Barker, Roger A

2018-05-29

We report the cognitive features and progression of Parkinson's disease (PD) in five patients with concurrent Gaucher disease. The patients presented at an earlier age than patients with sporadic PD, as previously noted by others; but in contrast to many previous reports, our patients followed a variable clinical course. While two patients developed early cognitive deficits and dementia, three others remained cognitively intact over the follow-up period. Thus, in this small case series, PD in the context of GD more closely resembles idiopathic PD in terms of its clinical heterogeneity in contrast to PD associated with GBA heterozygote mutations.

Martian 'Brain'

NASA Technical Reports Server (NTRS)

2004-01-01

5 May 2004 Most middle-latitude craters on Mars have strange landforms on their floors. Often, the floors have pitted and convoluted features that lack simple explanation. In this case, the central part of the crater floor shown in this 2004 Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image bears some resemblance to the folded nature of a brain. Or not. It depends upon the 'eye of the beholder,' perhaps. The light-toned 'ring' around the 'brain' feature is more easily explained--windblown ripples and dunes. The crater occurs near 33.1oS, 91.2oW, and is illuminated from the upper left. The picture covers an area about 3 km (1.9 mi) across.

Galilei group with multiple central extension, vorticity, and entropy generation: Exotic fluid in 3 +1 dimensions

NASA Astrophysics Data System (ADS)

Das, Praloy; Ghosh, Subir

2017-12-01

A noncommutative extension of an ideal (Hamiltonian) fluid model in 3 +1 dimensions is proposed. The model enjoys several interesting features: it allows a multiparameter central extension in Galilean boost algebra (which is significant being contrary to the existing belief that a similar feature can appear only in 2 +1 -dimensions); noncommutativity generates vorticity in a canonically irrotational fluid; it induces a nonbarotropic pressure leading to a nonisentropic system. (Barotropic fluids are entropy preserving as the pressure depends only on the matter density.) Our fluid model is termed "exotic" since it has a close resemblance with the extensively studied planar (2 +1 dimensions) exotic models and exotic (noncommutative) field theories.

Subacute sclerosing panencephalitis presenting as neuromyelitis optica.

PubMed

Raut, Tushar Premraj; Singh, Maneesh Kumar; Garg, Ravindra Kumar; Naphade, Pravin Umakant

2012-12-14

Subacute sclerosing panencephalitis (SSPE) is a slowly progressing inflammatory and degenerative disorder of the brain caused by a mutant measles virus. The diagnosis of SSPE is based on characteristic clinical and EEG findings (periodic complexes) and demonstration of elevated antibody titres against measles in cerebrospinal fluid. SSPE can have atypical clinical features at the onset. The authors here report a case of a 3-year-old child who presented with vision loss followed 15 months later by quadriparesis with bladder involvement. These clinical features resembled that of neuromyelitis optica. However, as the disease progressed, appearance of myoclonic jerks, periodic discharges on EEG and positive cerebrospinal fluid serology for measles led to the final diagnosis of SSPE.

Subacute sclerosing panencephalitis presenting as neuromyelitis optica

PubMed Central

Raut, Tushar Premraj; Singh, Maneesh Kumar; Garg, Ravindra Kumar; Naphade, Pravin Umakant

2012-01-01

Subacute sclerosing panencephalitis (SSPE) is a slowly progressing inflammatory and degenerative disorder of the brain caused by a mutant measles virus. The diagnosis of SSPE is based on characteristic clinical and EEG findings (periodic complexes) and demonstration of elevated antibody titres against measles in cerebrospinal fluid. SSPE can have atypical clinical features at the onset. The authors here report a case of a 3-year-old child who presented with vision loss followed 15 months later by quadriparesis with bladder involvement. These clinical features resembled that of neuromyelitis optica. However, as the disease progressed, appearance of myoclonic jerks, periodic discharges on EEG and positive cerebrospinal fluid serology for measles led to the final diagnosis of SSPE. PMID:23242079

Agarose-based biomaterials for tissue engineering.

PubMed

Zarrintaj, Payam; Manouchehri, Saeed; Ahmadi, Zahed; Saeb, Mohammad Reza; Urbanska, Aleksandra M; Kaplan, David L; Mozafari, Masoud

2018-05-01

Agarose is a natural polysaccharide polymer having unique characteristics that give reason to consider it for tissue engineering applications. Special characteristics of agarose such as its excellent biocompatibility, thermo-reversible gelation behavior and physiochemical features support its use as a biomaterial for cell growth and/or controlled/localized drug delivery. The resemblance of this natural carbohydrate polymer to the extracellular matrix results in attractive features that bring about a strong interest in its usage in the field. The scope of this review is to summarize the extensive researches addressing agarose-based biomaterials in order to provide an in-depth understanding of its tissue engineering-related applications. Copyright © 2018 Elsevier Ltd. All rights reserved.

Composite, ordered material having sharp surface features

DOEpatents

D'Urso, Brian R.; Simpson, John T.

2006-12-19

A composite material having sharp surface features includes a recessive phase and a protrusive phase, the recessive phase having a higher susceptibility to a preselected etchant than the protrusive phase, the composite material having an etched surface wherein the protrusive phase protrudes from the surface to form a sharp surface feature. The sharp surface features can be coated to make the surface super-hydrophobic.

Ancient wet aeolian environments on Earth: Clues to presence of fossil/live microorganisms on Mars

USGS Publications Warehouse

Mahaney, W.C.; Milner, M.W.; Netoff, D.I.; Malloch, D.; Dohm, J.M.; Baker, V.R.; Miyamoto, H.; Hare, T.M.; Komatsu, G.

2004-01-01

Ancient wet aeolian (wet-sabkha) environments on Earth, represented in the Entrada and Navajo sandstones of Utah, contain pipe structures considered to be the product of gas/water release under pressure. The sediments originally had considerable porosity allowing the ingress of living plant structures, microorganisms, clay minerals, and fine-grained primary minerals of silt and sand size from the surface downward in the sedimentary column. Host rock material is of a similar size and porosity and presumably the downward migration of fine-grained material would have been possible prior to lithogenesis and final cementation. Recent field emission scanning electron microscopy (FESEM) and EDS (energy-dispersive spectrometry) examination of sands from fluidized pipes in the Early Jurassic Navajo Sandstone reveal the presence of fossil forms resembling fungal filaments, some bearing hyphopodium-like structures similar to those produced by modern tropical leaf parasites. The tropical origin of the fungi is consistent with the paleogeography of the sandstone, which was deposited in a tropical arid environment. These fossil fungi are silicized, with minor amounts of CaCO3 and Fe, and in some cases a Si/Al ratio similar to smectite. They exist as pseudomorphs, totally depleted in nitrogen, adhering to the surfaces of fine-grained sands, principally quartz and orthoclase. Similar wet aeolian paleoenvironments are suspected for Mars, especially following catastrophic sediment-charged floods of enormous magnitudes that are believed to have contributed to rapid formation of large water bodies in the northern plains, ranging from lakes to oceans. These events are suspected to have contributed to a high frequency of constructional landforms (also known as pseudocraters) related to trapped volatiles and water-enriched sediment underneath a thick blanket of materials that were subsequently released to the martian surface, forming piping structures at the near surface and constructional landforms at the surface. This constructional process on Mars may help unravel the complex history of some of the piping structures observed on Earth; on Earth, evidence for the constructional landforms has been all but erased and the near-surface piping structures exposed through millions of years of differential erosion and topographic inversion now occur as high-standing promontories. If the features on both Earth and Mars formed by similar processes, especially involving water and other volatiles, and since the piping structures of Earth provided suitable environments for life to thrive in, the martian features in the northern plains should be considered as prime targets for physico/mineral/chemical/microbiological analyses once the astrobiological exploration of the red planet begins in earnest. ?? 2004 Elsevier Inc. All rights reserved.

Ancient wet aeolian environments on Earth: clues to presence of fossil/live microorganisms on Mars

NASA Astrophysics Data System (ADS)

Mahaney, William C.; Milner, Michael W.; Netoff, D. I.; Malloch, David; Dohm, James M.; Baker, Victor R.; Miyamoto, Hideaki; Hare, Trent M.; Komatsu, Goro

2004-09-01

Ancient wet aeolian (wet-sabkha) environments on Earth, represented in the Entrada and Navajo sandstones of Utah, contain pipe structures considered to be the product of gas/water release under pressure. The sediments originally had considerable porosity allowing the ingress of living plant structures, microorganisms, clay minerals, and fine-grained primary minerals of silt and sand size from the surface downward in the sedimentary column. Host rock material is of a similar size and porosity and presumably the downward migration of fine-grained material would have been possible prior to lithogenesis and final cementation. Recent field emission scanning electron microscopy (FESEM) and EDS (energy-dispersive spectrometry) examination of sands from fluidized pipes in the Early Jurassic Navajo Sandstone reveal the presence of fossil forms resembling fungal filaments, some bearing hyphopodium-like structures similar to those produced by modern tropical leaf parasites. The tropical origin of the fungi is consistent with the paleogeography of the sandstone, which was deposited in a tropical arid environment. These fossil fungi are silicized, with minor amounts of CaCO 3 and Fe, and in some cases a Si/Al ratio similar to smectite. They exist as pseudomorphs, totally depleted in nitrogen, adhering to the surfaces of fine-grained sands, principally quartz and orthoclase. Similar wet aeolian paleoenvironments are suspected for Mars, especially following catastrophic sediment-charged floods of enormous magnitudes that are believed to have contributed to rapid formation of large water bodies in the northern plains, ranging from lakes to oceans. These events are suspected to have contributed to a high frequency of constructional landforms (also known as pseudocraters) related to trapped volatiles and water-enriched sediment underneath a thick blanket of materials that were subsequently released to the martian surface, forming piping structures at the near surface and constructional landforms at the surface. This constructional process on Mars may help unravel the complex history of some of the piping structures observed on Earth; on Earth, evidence for the constructional landforms has been all but erased and the near-surface piping structures exposed through millions of years of differential erosion and topographic inversion now occur as high-standing promontories. If the features on both Earth and Mars formed by similar processes, especially involving water and other volatiles, and since the piping structures of Earth provided suitable environments for life to thrive in, the martian features in the northern plains should be considered as prime targets for physico/mineral/chemical/microbiological analyses once the astrobiological exploration of the red planet begins in earnest.

Etmopterus lailae sp. nov., a new lanternshark (Squaliformes: Etmopteridae) from the Northwestern Hawaiian Islands.

PubMed

Ebert, David A; Papastamatiou, Yannis P; Kajiura, Stephen M; Wetherbee, Bradley M

2017-02-27

A new species of lanternshark, Etmopterus lailae (Squaliformes: Etmopteridae), is described from the Northwestern Hawaiian Islands, in the central North Pacific Ocean. The new species resembles other members of the "Etmopterus lucifer" clade in having linear rows of dermal denticles, and most closely resembles E. lucifer from Japan. The new species occurs along insular slopes around seamounts at depths between 314-384 m. It can be distinguished from other members of the E. lucifer clade by a combination of characteristics, including a longer anterior flank marking branch, arrangement of dermal denticles on the ventral snout surface and body, flank and caudal markings, and meristic counts including number of spiral valve turns, and precaudal vertebrate. A key to species of the Etmopterus lucifer-clade is included.

A search for ultraviolet circumstellar gas absorption features in alpha Piscis Austrinus (Fomalhaut), a possible Beta Pictoris-like system

NASA Technical Reports Server (NTRS)

Cheng, K.-P.; Bruhweiler, Fred C.; Kondo, Yoji

1994-01-01

Archival high-dispersion International Ultraviolet Explorer (IUE) spectra have been used to search for circumstellar gas absorption features in alpha PsA (A3 V), a nearby (6.7 pc) proto-planetary system candidate. Recent sub-millimeter mapping observations around the region of alpha PsA indicate a spatially resolved dust disk like the one seen around Beta Pic. To determine how closely this putative disk resembles that of Beta Pic, we have searched for signatures of circumstellar gaseous absorption in all the available IUE high-dispersion data of alpha PsA. Examination of co-added IUE spectra shows weak circumstellar absorptions from excited levels in the resonance multiplet of Fe II near 2600 A. We also conclude that the sharp C I feature near 1657 A, previously identified as interstellar absorption toward alpha PsA, likely has a circumstellar origin. However, because the weakness of these absorption features, we will consider the presence of circumstellar gas as tentative and should be verified by using the Goddard High-Resolution Spectrograph aboard the Hubble Space Telescope. No corresponding circumstellar absorption is detected in higher ionization Fe III and Al III. Since the collisionally ionized nonphotospheric Al III resonance absorption seen in Beta Pic is likely formed close to the stellar surface, its absence in the UV spectra of alpha PsA could imply that, in contrast with Beta Pic, there is no active gaseous disk infall onto the central star. In the alpha PsA gaseous disk, if we assume a solar abundance for iron and all the iron is in the form of Fe II, plus a disk temperature of 5000 K, the Fe II UV1 absorption at 2611.8743 A infers a total hydrogen column density along the line of sight through the circumstellar disk of N(H) approximately equals 3.8 x 10(exp 17)/cm.

Replication of surface features from a master model to an amorphous metallic article

DOEpatents

Johnson, William L.; Bakke, Eric; Peker, Atakan

1999-01-01

The surface features of an article are replicated by preparing a master model having a preselected surface feature thereon which is to be replicated, and replicating the preselected surface feature of the master model. The replication is accomplished by providing a piece of a bulk-solidifying amorphous metallic alloy, contacting the piece of the bulk-solidifying amorphous metallic alloy to the surface of the master model at an elevated replication temperature to transfer a negative copy of the preselected surface feature of the master model to the piece, and separating the piece having the negative copy of the preselected surface feature from the master model.

Using Study Guides To Help Students Focus Their Reading in the Basic Course.

ERIC Educational Resources Information Center

Blakeman, David A.; Young, Raymond W.

One problem that surfaced with the speech communication basic course (COM 105) at Valdosta State University (Georgia) was that the actual content covered by individual instructors varied widely, so widely that two given sections taught by different instructors may bear little resemblance to one another. This problem was addressed first through a…

Historical open forest ecosystems in the Missouri Ozarks: reconstruction and restoration targets

Treesearch

Brice B. Hanberry; D. Todd Jones-Farrand; John M. Kabrick

2014-01-01

Current forests no longer resemble historical open forest ecosystems in the eastern United States. In the absence of representative forest ecosystems under a continuous surface fire regime at a large scale, reconstruction of historical landscapes can provide a reference for restoration efforts. For initial expert-assigned vegetation phases ranging from prairie to...

Optical observations of NGC 2915: A nearby blue compact dwarf galaxy

NASA Technical Reports Server (NTRS)

Meurer, G. R.; Mackie, G.; Carignan, C.

1994-01-01

This paper presents B and R band Charge Coupled Device (CCD) images and medium resolution spectroscopy of NGC 2915, a relatively isolated BCD (blue compact dwarf) galaxy at a distance of approximately 5 Mpc. NGC 2915 contains two stellar populations: a high surface brightness blue core population and a red diffuse population. The core population contains all of the H II, and numerous embedded objects. It is the locus of current high mass star formation. The brightest embedded objects are likely to be young ionizing clusters, while many of the fainter objects are likely to be individual supergiant stars with masses up to approximately 25 solar mass, or blends of a few such stars. Curious aligned structures on the SE side of the galaxy are seen and their nature discussed. The spectrum of the core is dominated by bright narrow emission lines like that of a high excitation and low metallicity (less than half solar) H II region. The continuum is flat, with Balmer and Ca II features seen in absorption. The velocity of the Ca II features suggest contamination by galactic interstellar absorption. There is a significant velocity gradient in the spectra, probably indicative of rotation. Outside of its core, NGC 2915 resembles a dE (dwarf elliptical) galaxy, in that it has an exponential surface brightness profile, is red ((B-R)(sub 0) = 1.65), and has a low extrapolated central surface brightness (B(0)(sub c) = 22.44). NGC 2915's properties are compared with other BCDs, concentrating on two morphologically similar BCDs that are near enough to resolve into stars: NGC 1705 and NGC 5253. It is noted that the presence of winds in BCDs invalidates closed box chemical evolution models and the remaining constraints on star formation duration are relatively weak. Some BCDs, including NGC 2915, may be able to maintain their present star formation rate for Gyr time scales. This suggests that the overall evolution of these BCDs may be much slower than the approximately 10 Myr burst time scales commonly quoted. However, shortly after the formation of a massive (10(exp 6) solar mass) cluster a BCD will have all the properties of strong starburst galaxy).

A new seamless, smooth, interior, absorptive finishing system

NASA Astrophysics Data System (ADS)

D'Antonio, Peter

2003-04-01

Architects and acousticians have sought a field-applied, absorptive finishing system that resembles a smooth plaster or painted drywall surface, since the dawn of architectural acoustics. Some success has been achieved using sprayed cellulose or cementitious materials, but surface smoothness has been a challenge. A new approach utilizing a thin microporous layer of mineral particles applied over a mineral wool panel will be described. This material can be applied to almost any shape surface, internally pigmented to match almost any color and renovated. It is currently finding application in many architectural applications, including museums. A recent installation in the New Pinakothek Museum in Munich will be illustrated.

Psoriasiform Keratosis - Case report*

PubMed Central

Pires, Carla Andréa Avelar; de Sousa, Brena Andrade; do Nascimento, Carla do Socorro Silva; Moutinho, Ana Thais Machado; de Miranda, Mario Fernando Ribeiro; Carneiro, Francisca Regina Oliveira

2014-01-01

Psoriasiform Keratosis is a rare clinic entity. The etiopathogenesis remains unknown and the disease is characterized by a solitary, scaly or keratotic papule, or plaque mainly located on the extremities. Histopathological features closely resemble those of psoriasis. We report the case of a 70-year-old woman presenting a solitary and asymptomatic keratotic plaque, located on the back of the left leg, unresponsive to topical corticosteroids. We performed an excisional biopsy and histopathology was consistent with psoriasiform keratosis. PMID:24770510

Multiple spinal nerve enlargement and SOS1 mutation: Further evidence of overlap between neurofibromatosis type 1 and Noonan phenotype.

PubMed

Santoro, C; Giugliano, T; Melone, M A B; Cirillo, M; Schettino, C; Bernardo, P; Cirillo, G; Perrotta, S; Piluso, G

2018-01-01

Neurofibromatosis type 1 (NF1) has long been considered a well-defined, recognizable monogenic disorder, with neurofibromas constituting a pathognomonic sign. This dogma has been challenged by recent descriptions of patients with enlarged nerves or paraspinal tumors, suggesting that neurogenic tumors and hypertrophic neuropathy may be a complication of Noonan syndrome with multiple lentigines (NSML) or RASopathy phenotype. We describe a 15-year-old boy, whose mother previously received clinical diagnosis of NF1 due to presence of bilateral cervical and lumbar spinal lesions resembling plexiform neurofibromas and features suggestive of NS. NF1 molecular analysis was negative in the mother. The boy presented with Noonan features, multiple lentigines and pectus excavatum. Next-generation sequencing analysis of all RASopathy genes identified p.Ser548Arg missense mutation in SOS1 in the boy, confirmed in his mother. Brain and spinal magnetic resonance imaging scans were negative in the boy. No heart involvement or deafness was observed in proband or mother. This is the first report of a SOS1 mutation associated with hypertrophic neuropathy resembling plexiform neurofibromas, a rare complication in Noonan phenotypes with mutations in RASopathy genes. Our results highlight the overlap between RASopathies, suggesting that NF1 diagnostic criteria need rethinking. Genetic analysis of RASopathy genes should be considered when diagnosis is uncertain. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Inferior Cerebellar Hypoplasia Resembling a Dandy-Walker-Like Malformation in Purebred Eurasier Dogs with Familial Non-Progressive Ataxia: A Retrospective and Prospective Clinical Cohort Study

PubMed Central

Bernardino, Filipa; Rentmeister, Kai; Schmidt, Martin J.; Bruehschwein, Andreas; Matiasek, Kaspar; Matiasek, Lara A.; Lauda, Alexander; Schoon, Heinz A.; Fischer, Andrea

2015-01-01

Cerebellar malformations can be inherited or caused by insults during cerebellar development. To date, only sporadic cases of cerebellar malformations have been reported in dogs, and the genetic background has remained obscure. Therefore, this study`s objective was to describe the clinical characteristics, imaging features and pedigree data of a familial cerebellar hypoplasia in purebred Eurasier dogs. A uniform cerebellar malformation characterized by consistent absence of the caudal portions of the cerebellar vermis and, to a lesser degree, the caudal portions of the cerebellar hemispheres in association with large retrocerebellar fluid accumulations was recognized in 14 closely related Eurasier dogs. Hydrocephalus was an additional feature in some dogs. All dogs displayed non-progressive ataxia, which had already been noted when the dogs were 5 – 6 weeks old. The severity of the ataxia varied between dogs, from mild truncal sway, subtle dysmetric gait, dysequilibrium and pelvic limb ataxia to severe cerebellar ataxia in puppies and episodic falling or rolling. Follow-up examinations in adult dogs showed improvement of the cerebellar ataxia and a still absent menace response. Epileptic seizures occurred in some dogs. The association of partial vermis agenesis with an enlarged fourth ventricle and an enlarged caudal (posterior) fossa resembled a Dandy-Walker-like malformation in some dogs. Pedigree analyses were consistent with autosomal recessive inheritance. PMID:25668516

Initial bioadhesion on dental materials as a function of contact time, pH, surface wettability, and isoelectric point.

PubMed

Müller, Christine; Lüders, Anne; Hoth-Hannig, Wiebke; Hannig, Matthias; Ziegler, Christiane

2010-03-16

The adsorption of bovine serum albumin (BSA) on surfaces of dental enamel and of dental materials was investigated by scanning force spectroscopy. This method provides adhesion forces which can be measured as a function of contact time between protein and surface, pH, wettability, and isoelectric point of the surface. Whereas the chosen ceramic and composite materials resemble very well the adhesion on natural enamel, a much stronger adhesion was found for the more hydrophobic surfaces, that is, gold, titanium, poly(methyl methacrylate) (PMMA), and poly(tetrafluoroethylene) (PTFE). On hydrophilic surfaces, adhesion is mainly influenced by the electrostatic forces between protein and surface. However, the conformational change of BSA at pH values above pH 8 has to be taken into account. On the very hydrophobic PTFE surface, the special interface structure between PTFE and water plays an important role which governs BSA adhesion.

HPV-related Multiphenotypic Sinonasal Carcinoma: An Expanded Series of 49 Cases of the Tumor Formerly Known as HPV-related Carcinoma With Adenoid Cystic Carcinoma-like Features.

PubMed

Bishop, Justin A; Andreasen, Simon; Hang, Jen-Fan; Bullock, Martin J; Chen, Tiffany Y; Franchi, Alessandro; Garcia, Joaquin J; Gnepp, Douglas R; Gomez-Fernandez, Carmen R; Ihrler, Stephan; Kuo, Ying-Ju; Lewis, James S; Magliocca, Kelly R; Pambuccian, Stefan; Sandison, Ann; Uro-Coste, Emmanuelle; Stelow, Edward; Kiss, Katalin; Westra, William H

2017-12-01

Human papillomavirus (HPV)-related multiphenotypic sinonasal carcinoma (HMSC), originally known as HPV-related carcinoma with adenoid cystic carcinoma-like features, is a peculiar neoplasm that is restricted to the sinonasal tract, exhibits features of both a surface-derived and salivary gland carcinoma (particularly adenoid cystic carcinoma), and is associated with high-risk HPV. Given the limited number of published cases, the full clinicopathologic spectrum of this neoplasm is unclear. Here, we present an updated experience of 49 cases. All cases of HMSC were obtained from the authors' files. Immunohistochemistry for p16, c-kit, and myoepithelial cell markers (S100, actin, calponin, p63, and/or p40) was performed along with RNA in situ hybridization for HPV (type 33-specific as well as a high-risk cocktail). Fluorescence in situ hybridization studies for fusions of MYB, NFIB, and MYBL1 was performed on a subset of cases. Clinical follow-up was obtained from medical records. A total of 49 cases of HMSC were collected. Twenty-eight (57%) were from women and 18 (43%) from men, ranging in age from 28 to 90 years (mean, 54 y). Of 40 cases with detailed staging information, 43% of HMSCs presented with a high T-stage (T3 or T4). Histologically, most grew predominantly as solid nests of basaloid cells exhibiting high mitotic rates and frequent necrosis, with histologic and immunohistochemical evidence of myoepithelial differentiation. Most cases also demonstrated foci of cribriform and/or tubular growth, along with an inconspicuous population of ducts. Thirty-four (69%) cases demonstrated an unusual pattern of surface involvement where markedly atypical squamous cells colonized tracts of the sinonasal mucosa. Less consistent histologic features included squamous differentiation within the invasive tumor (n=6), sarcomatoid transformation (n=5) including overt chondroid differentiation (n=3), and prominent epithelial-myoepithelial carcinoma-like growth (n=3). All cases were positive for p16 by immunostaining and HPV by RNA in situ hybridization. Thirty-three (67%) were positive for HPV 33. No cases tested for MYB, MYBL1, or NFIB gene fusions were positive. In the 38 cases with follow-up data, (mean follow-up, 42 mo) 14 recurred locally and 2 metastasized (lung, finger). There were no regional lymph node metastases, and no tumor-related deaths. HMSC is a distinct sinonasal neoplasm characterized by myoepithelial differentiation, frequent surface epithelial involvement, and the presence of high-risk HPV (especially type 33). Although it classically exhibits a cribriforming pattern that closely resembles adenoid cystic carcinoma, our expanded series highlights a histologic spectrum that is much broader than previously recognized, warranting a change in terminology. HMSC usually presents as a large and destructive sinonasal mass with high-grade histologic features, but it paradoxically behaves in a relatively indolent manner, underscoring the importance of distinguishing HMSC from true adenoid cystic carcinoma, squamous cell carcinoma, and other histologic mimickers.

Capturing 2D transient surface data of granular flows against obstacles with an RGB-D sensor

NASA Astrophysics Data System (ADS)

Caviedes-Voullieme, Daniel; Juez, Carmelo; Murillo, Javier; Garcia-Navarro, Pilar

2014-05-01

Landslides are an ubiquitous natural hazard, and therefore human infrastructure and settlements are often at risk in mountainous regions. In order to better understand and predict landslides, systematic studies of the phenomena need to be undertaken. In particular, computational tools which allow for analysis of field problems require to be thoroughly tested, calibrated and validated under controlled conditions. And to do so, it is necessary for such controlled experiments to be fully characterized in the same terms as the numerical model requires. This work presents an experimental study of dry granular flow over a rough bed with topography which resembles a mountain valley. It has an upper region with a very high slope. The geometry of the bed describes a fourth order polynomial curve, with a low point with zero slope, and afterwards a short region with adverse slope. Obstacles are present in the lower regions which are used as model geometries of human structures. The experiments consisted of a sudden release a mass of sand on the upper region, and allowing it to flow downslope. Furthermore, it has been frequent in previous studies to measure final states of the granular mass at rest, but seldom has transient data being provided, and never for the entire field. In this work we present transient measurements of the moving granular surfaces, obtained with a consumer-grade RGB-D sensor. The sensor, developed for the videogame industry, allows to measure the moving surface of the sand, thus obtaining elevation fields. The experimental results are very consistent and repeatable. The measured surfaces clearly show the distinctive features of the granular flow around the obstacles and allow to qualitatively describe the different flow patterns. More importantly, the quantitative description of the granular surface allows for benchmarking and calibration of predictive numerical models, key in scaling the small-scale experimental knowledge into the field.

A new species of antipatharian coral (Cnidaria: Anthozoa: Antipatharia: Schizopathidae) from the Pacific coast of Costa Rica

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

Opresko, Dennis M; Breedy, Odalisca

A new species of black coral, Aphanipathes colombiana (Cnidaria:Antipatharia) from the Caribbean coast of Colombia is described. The species forms small flabellate colonies with anisomorphic polypar spines. It is morphologically similar to the western Atlantic species A. thyoides (Pourtales) but its hypostomal polypar spines are not reduced in size. The new species also resembles the Indo-Pacific species A. reticulata van Pesch but it has smooth-surfaced polypar spines, whereas in A. reticulata these spines have small tubercles on their surface

An experimental study of the atmospheric boundary layer modified by a change in surface roughness and surface temperature

NASA Technical Reports Server (NTRS)

Tieleman, H. W.; Derrington, D. B., Jr.

1977-01-01

Turbulent flow, resembling an on-shore flow from the ocean crossing the beach at an oblique angle, is investigated. Measurements of this flow have been taken at high sample rates and include measurements at various heights, high enough to describe the portion of the mean wind and temperature profiles and fluxes that are of interest for the solution of practical engineering problems. These problems could include air pollution (fumigation and plume trapping), operation of low flying aircraft, crop-spraying and crop-dusting operations.

Realistic Free-Spins Features Increase Preference for Slot Machines.

PubMed

Taylor, Lorance F; Macaskill, Anne C; Hunt, Maree J

2017-06-01

Despite increasing research into how the structural characteristics of slot machines influence gambling behaviour there have been no experimental investigations into the effect of free-spins bonus features-a structural characteristic that is commonly central to the design of slot machines. This series of three experiments investigated the free-spins feature using slot machine simulations to determine whether participants allocate more wagers to a machine with free spins, and, which components of free-spins features drive this preference. In each experiment, participants were exposed to two computer-simulated slot machines-one with a free-spins feature or similar bonus feature and one without. Participants then completed a testing phase where they could freely switch between the two machines. In Experiment 1, participants did not prefer the machine with a simple free-spins feature. In Experiment 2 the free-spins feature incorporated additional elements such as sounds, animations, and an increased win frequency; participants preferred to gamble on this machine. The Experiment 3 "bonus feature" machine resembled the free spins machine in Experiment 2 except spins were not free; participants showed a clear preference for this machine also. These findings indicate that (1) free-spins features have a major influence over machine choice and (2) the "freeness" of the free-spins bonus features is not an important driver of preference, contrary to self-report and interview research with gamblers.

Searching for the buried memory of past strong earthquakes on strike-slip faults

NASA Astrophysics Data System (ADS)

Garambois, S.; Manighetti, I.; Malavieille, J.; Langridge, R. M.; Davies, T. R.

2009-12-01

On strike-slip faults, the effect of a large earthquake is to suddenly displace the ground surface laterally, often by up to several meters. A consequence is the lateral offset, hence lateral separation, of the preexisting ground features. In alluvial settings, the dominant surface features are the stream network and related sediments. Where ongoing sedimentation is significant, the surface imprints of an earthquake may be rapidly buried under fresh sediments so that, when the next seismic event occurs (if not too close in time from the previous one), it offsets and deforms a younger soil layer possibly holding new markers such as newly formed drainage channels. Hence as earthquakes repeat on a strike-slip fault under ongoing sedimentation, the subsurface should keep part of their memory more or less buried in the form of distinctly offset markers, lying at various depths (0-10 m) in the ground. To search for that buried memory, we need non-invasive investigation methods, allowing imaging the sub-surface down to depths of several meters to 10s of meters. Ground penetrating radar (GPR) has appropriate resolution and acquisition time, provided that the subsurface layers are not too electrically conductive. We have performed serial 2D GPR profiles using 100 MHz antennas along several major strike-slip faults in New Zealand. In particular, at the Mason river site on the Hope dextral fault, four 450 m-long profiles were recorded parallel to the fault, two on each northern and southern compartments of the fault, whose surfaces are made of the 14-26 ka-old Terako alluvial terrace. The processed GPR data show the ground architecture only down to 5 meters in such conductive sediments. The profiles however reveal a number of places along the fault where the reflector pile is deflected at depth to form concave-up patterns. Some of those buried features have their edges extending up to the ground surface, what suggests they may post-date the Terako terrace surface. Most of them have very specific shapes which, on one hand, suggest that they likely are abandoned stream channels, and on the other hand, make them clearly distinguishable from one another. Interestingly, the overall arrangement and pattern of the markers identified in the northern compartment resembles that of the southern markers, the only clear difference being the lateral dextral offset of the southern marker series with respect to the northern one. Such lateral offset is compatible with the actual dextral slip on the fault, and suggests that the shallow buried markers have been laterally displaced by up to 30 meters. Knowing the fast slip rate of the Hope fault (about 20 mm/yr), the observed offsets might be the shallow buried signature of the few last major earthquakes on the fault. Though our results are preliminary and need further refinements, they show that GPR allows rapid investigation of large zones along faults, and has the potential to recover the buried memory of the past strong earthquakes on these faults.

Learned Compact Local Feature Descriptor for Tls-Based Geodetic Monitoring of Natural Outdoor Scenes

NASA Astrophysics Data System (ADS)

Gojcic, Z.; Zhou, C.; Wieser, A.

2018-05-01

The advantages of terrestrial laser scanning (TLS) for geodetic monitoring of man-made and natural objects are not yet fully exploited. Herein we address one of the open challenges by proposing feature-based methods for identification of corresponding points in point clouds of two or more epochs. We propose a learned compact feature descriptor tailored for point clouds of natural outdoor scenes obtained using TLS. We evaluate our method both on a benchmark data set and on a specially acquired outdoor dataset resembling a simplified monitoring scenario where we successfully estimate 3D displacement vectors of a rock that has been displaced between the scans. We show that the proposed descriptor has the capacity to generalize to unseen data and achieves state-of-the-art performance while being time efficient at the matching step due the low dimension.

High-altitude cerebral oedema mimicking stroke.

PubMed

Yanamandra, Uday; Gupta, Amul; Patyal, Sagarika; Varma, Prem Prakash

2014-03-26

High-altitude cerebral oedema (HACO) is the most fatal high-altitude illness seen by rural physicians practising in high-altitude areas. HACO presents clinically with cerebellar ataxia, features of raised intracranial pressure (ICP) and coma. Early identification is important as delay in diagnosis can be fatal. We present two cases of HACO presenting with focal deficits mimicking stroke. The first patient presented with left-sided hemiplegia associated with the rapid deterioration in the sensorium. Neuroimaging revealed features suggestive of vasogenic oedema. The second patient presented with monoplegia of the lower limb. Neuroimaging revealed perfusion deficit in anterior cerebral artery territory. Both patients were managed with dexamethasone and they improved dramatically. Clinical picture and neuroimaging closely resembled acute ischaemic stroke in both cases. Thrombolysis in these patients would have been disastrous. Recent travel to high altitude, young age, absence of atherosclerotic risk factors and features of raised ICP concomitantly directed the diagnosis to HACO.

Saliva with reduced calcium and phosphorous concentrations: Effect on erosion dental lesions.

PubMed

Denucci, Giovanna Corrêa; Mantilla, Taís Fonseca; Amaral, Flávia Lucisano Botelho; Basting, Roberta Tarkany; França, Fabiana Mantovani Gomes; Turssi, Cecilia Pedroso

2018-02-08

To investigate whether saliva formulations with reduced calcium (Ca) and inorganic phosphorous (Pi) concentration would affect dental erosion caused by hydrochloric acid (HCl). Enamel and root dentine bovine slabs were embedded, polished and measured for surface Knoop microhardness (SMH). After reference areas were created, specimens were exposed to HCl solution (0.01M; pH 2; 120s) and immersed in artificial salivas (6h) containing three different Ca/Pi concentrations (n=15), which simulate serum conditions of normo-, mild- or severe hypocalcaemia. The control group was immersed in Ca/Pi-free saliva. The study protocol was carried out 2x/day for 5 days. Surface loss of enamel and root dentine was assessed using an optical profilometer and SMH was remeasured for enamel. ANOVA (p<0.001) and Tukey's test showed that enamel loss in groups subjected to artificial salivas that simulated mild- or severe hypocalcaemia did not differ from that resembling normocalcemia. %SMH was lower when saliva was mildly- and normally-concentrated in Ca/Pi (p<0.001). Root dentine loss was higher in saliva simulating severe hypocalcaemia than in those referring to mild, hypo- and normocalcemia. Depending on the dental substrate, salivary formulations resembling serum hypocalcaemia affected surface loss due to erosion and rehardening thereof. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Self-Concept in Children with Down Syndrome

PubMed Central

Saha, Sayoni; Doran, Eric; Osann, Kathryn E.; Hom, Christy; Movsesyan, Nina; Rosa, Diana D.; Tournay, Anne; Lott, Ira T.

2015-01-01

Self-concept is a critical indicator of quality of life but few studies have examined this subject in children with Down syndrome (DS). In this study, we propose a novel methodology to assess the self-concept of children with DS by analyzing their responses towards two dolls, one with a “typically developing” (TD) appearance and one with the phenotypic features of DS. Fifty-four children with DS participated in play sessions with both dolls and were then interviewed to assess doll preference, resemblance, and attribution of positive qualities. We observed that children with DS: 1) exhibited a preference for the TD doll regardless of age, gender, IQ or self-awareness; 2) attributed more positive qualities to the TD doll than the DS doll; and 3) believed that they resembled the TD doll, rather than the more phenotypically accurate representation of themselves. Older participants were more likely to exhibit self-recognition by this technique. These findings contribute to current understandings of how people with DS view themselves and their disability. PMID:24838927

Palifermin-associated papular eruption.

PubMed

King, Brett; Knopp, Eleanor; Galan, Anjela; Nuovo, Gerard; Tigelaar, Robert; McNiff, Jennifer

2009-02-01

Palifermin is a recombinant human keratinocyte growth factor that is used to reduce the duration and severity of oral mucositis in patients undergoing hematopoietic stem cell transplantation after myelotoxic therapy. Cutaneous adverse reactions associated with keratinocyte growth factor are reported to be rash, pruritus, and erythema. After receiving palifermin following autologous hematopoietic stem cell transplantation and treatment with melphalan, a patient developed erythema and lichenoid papules that were distributed primarily in intertriginous areas. A biopsy specimen of the papules showed a striking resemblance to verrucae, but in situ hybridization studies were negative for human papillomavirus. Immunohistochemical staining with antibodies to Ki-67 and cytokeratin 5/6 showed increased keratinocyte proliferation in lesional skin. After treatment with palifermin, a papular eruption clinically resembling lichen planus or plane warts, with histologic features of verruca plana, and intertriginous erythema may occur. In this case, neither eruption required treatment, and spontaneous resolution was observed over days to weeks. Histopathologic staining patterns of Ki-67 and cytokeratin 5/6 may be useful in identifying adverse reactions to palifermin therapy.

Nucleotide sequence of the Saccharomyces cerevisiae PUT4 proline-permease-encoding gene: similarities between CAN1, HIP1 and PUT4 permeases.

PubMed

Vandenbol, M; Jauniaux, J C; Grenson, M

1989-11-15

The complete nucleotide (nt) sequence of the PUT4 gene, whose product is required for high-affinity proline active transport in the yeast Saccharomyces cerevisiae, is presented. The sequence contains a single long open reading frame of 1881 nt, encoding a polypeptide with a calculated Mr of 68,795. The predicted protein is strongly hydrophobic and exhibits six potential glycosylation sites. Its hydropathy profile suggests the presence of twelve membrane-spanning regions flanked by hydrophilic N- and C-terminal domains. The N terminus does not resemble signal sequences found in secreted proteins. These features are characteristic of integral membrane proteins catalyzing translocation of ligands across cellular membranes. Protein sequence comparisons indicate strong resemblance to the arginine and histidine permeases of S. cerevisiae, but no marked sequence similarity to the proline permease of Escherichia coli or to other known prokaryotic or eukaryotic transport proteins. The strong similarity between the three yeast amino acid permeases suggests a common ancestor for the three proteins.

A comparison between general circulation model simulations using two sea surface temperature datasets for January 1979

NASA Technical Reports Server (NTRS)

Ose, Tomoaki; Mechoso, Carlos; Halpern, David

1994-01-01

Simulations with the UCLA atmospheric general circulation model (AGCM) using two different global sea surface temperature (SST) datasets for January 1979 are compared. One of these datasets is based on Comprehensive Ocean-Atmosphere Data Set (COADS) (SSTs) at locations where there are ship reports, and climatology elsewhere; the other is derived from measurements by instruments onboard NOAA satellites. In the former dataset (COADS SST), data are concentrated along shipping routes in the Northern Hemisphere; in the latter dataset High Resolution Infrared Sounder (HIRS SST), data cover the global domain. Ensembles of five 30-day mean fields are obtained from integrations performed in the perpetual-January mode. The results are presented as anomalies, that is, departures of each ensemble mean from that produced in a control simulation with climatological SSTs. Large differences are found between the anomalies obtained using COADS and HIRS SSTs, even in the Northern Hemisphere where the datasets are most similar to each other. The internal variability of the circulation in the control simulation and the simulated atmospheric response to anomalous forcings appear to be linked in that the pattern of geopotential height anomalies obtained using COADS SSTs resembles the first empirical orthogonal function (EOF 1) in the control simulation. The corresponding pattern obtained using HIRS SSTs is substantially different and somewhat resembles EOF 2 in the sector from central North America to central Asia. To gain insight into the reasons for these results, three additional simulations are carried out with SST anomalies confined to regions where COADS SSTs are substantially warmer than HIRS SSTs. The regions correspond to warm pools in the northwest and northeast Pacific, and the northwest Atlantic. These warm pools tend to produce positive geopotential height anomalies in the northeastern part of the corresponding oceans. Both warm pools in the Pacific produce large-scale circulation anomalies with a pattern that resembles that obtained using COADS SSTs as well as EOF 1 of the control simulation; the warm pool in the Atlantic does not. These results suggest that the differences obtained with COADS SSTs and HIRS SSTs are mostly due to the differences in the datasets over the northern Pacific. There was a blocking episode near Greenland in late January 1979. Both simulations with warm SST anomalies over the northwest and northeast Pacific show a tendency toward increased incidence of North Atlantic blocking; the simulation with warm SST anomalies over the northwest Atlantic shows a tendency toward decreased incidence. These results suggest that features in both SST datasets that do not have a counterpart in the other dataset contribute signficantly to the differences between the simulated and observed fields. The results of this study imply that uncertainties in current SST distributions for the world oceans can be as important as the SST anomalies themselves in terms of their impact on the atmospheric circulation. Caution should be exercised, therefore, when linking anomalous circulation and SST patterns, especially in long-range prediction.

Airborne electromagnetic detection of shallow seafloor topographic features, including resolution of multiple sub-parallel seafloor ridges

NASA Astrophysics Data System (ADS)

Vrbancich, Julian; Boyd, Graham

2014-05-01

The HoistEM helicopter time-domain electromagnetic (TEM) system was flown over waters in Backstairs Passage, South Australia, in 2003 to test the bathymetric accuracy and hence the ability to resolve seafloor structure in shallow and deeper waters (extending to ~40 m depth) that contain interesting seafloor topography. The topography that forms a rock peak (South Page) in the form of a mini-seamount that barely rises above the water surface was accurately delineated along its ridge from the start of its base (where the seafloor is relatively flat) in ~30 m water depth to its peak at the water surface, after an empirical correction was applied to the data to account for imperfect system calibration, consistent with earlier studies using the same HoistEM system. A much smaller submerged feature (Threshold Bank) of ~9 m peak height located in waters of 35 to 40 m depth was also accurately delineated. These observations when checked against known water depths in these two regions showed that the airborne TEM system, following empirical data correction, was effectively operating correctly. The third and most important component of the survey was flown over the Yatala Shoals region that includes a series of sub-parallel seafloor ridges (resembling large sandwaves rising up to ~20 m from the seafloor) that branch out and gradually decrease in height as the ridges spread out across the seafloor. These sub-parallel ridges provide an interesting topography because the interpreted water depths obtained from 1D inversion of TEM data highlight the limitations of the EM footprint size in resolving both the separation between the ridges (which vary up to ~300 m) and the height of individual ridges (which vary up to ~20 m), and possibly also the limitations of assuming a 1D model in areas where the topography is quasi-2D/3D.

Compliant seal development

NASA Technical Reports Server (NTRS)

Hendricks, Robert C.

1993-01-01

The compliant metallic seal combines the noncontact feature of the labyrinth seal, the low leakage of a mechanical seal, and the compliant nature of the brush seal. It consists of several thin metallic elements or leaves mounted within a ring which is press fit into the housing, and in form, sort of resembles a lip seal sections wiping the shaft. A second set of overlapping cover leaves are placed on top of the shaft riding leaves which reduces leakage and provides stiffness. The leaves can be straight or angle cut. The shaft riding fingers are designed with mismatched curvature to provide lift off similar to the Rayleigh lift pads in mechanical seals with leading edge clearances nearly twice those of the trailing edge as as shown by Fleming to be optimal for gas flows in convergent seal passages. Leading edge clearances range from 300 to 500 microinches. Balance pockets beneath the leaves provide fluid film feed to the 'Rayleigh lift' surface and the proper balance ratio (mechanical seal) when combined with the static pressure and film pressure. The leaves flex in the radial direction and accommodate thermomechanical behavior as well as axial motion and angular misalignment. In the static mode, there is a net closing force on the leaves. The seals were tested to 70 psi at speeds to 16,000 rpm or surface speeds to 330 fps and temperatures from ambient to 440 F. A slow cycle through the rig critical at 10,000 rpm induced a radial vibration response of 0.004 to 0.005 inch were accommodated by the seal. Preliminary performance data are encouraging demonstrating hydrodynamic liftoff and noncontacting operation at pressure and speeds typical of gas turbine engines. The leakage performance data are significantly better than commercial labyrinth and brush seals which should be expected as this design incorporates the features of the low leakage face or mechanical seal along with the flexibility of the brush configuration.

Reflectance spectroscopy of ferric sulfate-bearing montmorillonites as Mars soil analog materials

NASA Technical Reports Server (NTRS)

Bishop, J. L.; Pieters, C. M.; Burns, R. G.; Edwards, J. O.; Mancinelli, R. L.; Froschl, H.

1995-01-01

Spectroscopic analyses have shown that smectites enhanced in the laboratory with additional ferric species exhibit important similarities to those of the soils on Mars. Ferrihydrite in these chemically treated smectites has features in the visible to near-infrared region that resemble the energies and band strengths of features in reflectance spectra observed for several bright regions on Mars. New samples have been prepared with sulfate as well, because S was found by Viking to be a major component in the surface material on Mars. A suite of ferrihydrite-bearing and ferric sulfate-bearing montmorillonites, prepared with variable Fe3+ and S concentrations and variable pH conditions, has been analyzed using reflectance spectroscopy in the visible and infrared regions, Mossbauer spectroscopy at room temperature and 4 K, differential thermal analysis, and X-ray diffraction. These analyses support the formation of ferrihydrite of variable crystallinity in the ferrihydrite-bearing montmorillonites and a combination of schwertmannite and ferrihydrite in the ferric sulfate-bearing montmorillonites. Small quantities of poorly crystalline or nanophase forms of other ferric materials may also be present in these samples. The chemical formation conditions of the ferrihydrite-bearing and ferric sulfate-bearing montmorillonites influence the character of the low temperature Mossbauer sextets and the visible reflectance spectra. An absorption minimum is observed at 0.88-0.89 micrometers in spectra of the ferric sulfate-bearing samples, and at 0.89-0.92 micrometers in spectra of the ferrihydrate-bearing montmorillonites. Mossbauer spectra of the ferric sulfate-bearing montmorillonites indicate variable concentrations of ferrihydrite and schwertmannite in the interlaminar spaces and along grain surfaces. Dehydration under reduced atmospheric pressure conditions induces a greater effect on the adsorbed and interlayer water in ferrihydrite-bearing montmorillonite than on the water in ferric sulfate-bearing montmorillonite. Reflectance spectra of ferric sulfate-bearing montmorillonite include a strong 3-micrometers band that is more resistant to dry atmospheric conditions than the 3-micrometers band in spectra of similarly prepared ferrihydrite-bearing montmorillonites.

Compliant seal development

NASA Astrophysics Data System (ADS)

Hendricks, Robert C.

1993-10-01

The compliant metallic seal combines the noncontact feature of the labyrinth seal, the low leakage of a mechanical seal, and the compliant nature of the brush seal. It consists of several thin metallic elements or leaves mounted within a ring which is press fit into the housing, and in form, sort of resembles a lip seal sections wiping the shaft. A second set of overlapping cover leaves are placed on top of the shaft riding leaves which reduces leakage and provides stiffness. The leaves can be straight or angle cut. The shaft riding fingers are designed with mismatched curvature to provide lift off similar to the Rayleigh lift pads in mechanical seals with leading edge clearances nearly twice those of the trailing edge as as shown by Fleming to be optimal for gas flows in convergent seal passages. Leading edge clearances range from 300 to 500 microinches. Balance pockets beneath the leaves provide fluid film feed to the 'Rayleigh lift' surface and the proper balance ratio (mechanical seal) when combined with the static pressure and film pressure. The leaves flex in the radial direction and accommodate thermomechanical behavior as well as axial motion and angular misalignment. In the static mode, there is a net closing force on the leaves. The seals were tested to 70 psi at speeds to 16,000 rpm or surface speeds to 330 fps and temperatures from ambient to 440 F. A slow cycle through the rig critical at 10,000 rpm induced a radial vibration response of 0.004 to 0.005 inch were accommodated by the seal. Preliminary performance data are encouraging demonstrating hydrodynamic liftoff and noncontacting operation at pressure and speeds typical of gas turbine engines. The leakage performance data are significantly better than commercial labyrinth and brush seals which should be expected as this design incorporates the features of the low leakage face or mechanical seal along with the flexibility of the brush configuration.

Revisiting the Cause of the 1989-2009 Arctic Surface Warming Using the Surface Energy Budget: Downward Infrared Radiation Dominates the Surface Fluxes

NASA Astrophysics Data System (ADS)

Lee, Sukyoung; Gong, Tingting; Feldstein, Steven B.; Screen, James A.; Simmonds, Ian

2017-10-01

The Arctic has been warming faster than elsewhere, especially during the cold season. According to the leading theory, ice-albedo feedback warms the Arctic Ocean during the summer, and the heat gained by the ocean is released during the winter, causing the cold-season warming. Screen and Simmonds (2010; SS10) concluded that the theory is correct by comparing trend patterns in surface air temperature (SAT), surface turbulence heat flux (HF), and net surface infrared radiation (IR). However, in this comparison, downward IR is more appropriate to use. By analyzing the same data used in SS10 using the surface energy budget, it is shown here that over most of the Arctic the skin temperature trend, which closely resembles the SAT trend, is largely accounted for by the downward IR, not the HF, trend.

Serum amyloid beta peptides in patients with dementia and age-matched non-demented controls as detected by surface-enhanced laser desorption ionisation-time of flight mass spectrometry (SELDI-TOF MS).

PubMed

Frankfort, Suzanne V; van Campen, Jos P C M; Tulner, Linda R; Beijnen, Jos H

2008-09-01

By using surface enhanced laser desorption/ionisation- time of flight mass spectrometry (SELDI-TOF MS) an amyloid beta (Abeta) profile was shown in cerebrospinal fluid (CSF) of patients with dementia. To investigate the Abeta-profile in serum with SELDI-TOF MS, to evaluate if this profile resembles CSF profiles and to investigate the correlation between intensity of Abeta-peptide-peaks in serum and clinical, demographical and genetic variables. Duplicate profiling of Abeta by an SELDI-TOF MS immunocapture assay was performed in 106 patients, suffering from Alzheimer's Disease or Vascular Dementia and age-matched non-demented control patients. Linear regression analyses were performed to investigate the intensities of four selected Abeta peaks as dependent variables in relation to the independent clinical, demographic or genetic variables. Abeta37, Abeta38 and Abeta40 were found among additional unidentified Abeta peptides, with the most pronounced Abeta peak at a molecular mass of 7752. This profile partly resembled the CSF profile. The clinical diagnosis was not a predictive independent variable, however ABCB1 genotypes C1236T, G2677T/A, age and creatinine level showed to be related to Abeta peak intensities in multivariate analyses. We found an Abeta profile in serum that partly resembled the CSF profile in demented patients. Age, creatinine levels, presence of the APOE epsilon4 allele and ABCB1 genotypes (C1236T and G2677T/A) were correlated with the Abeta serum profile. The role of P-gp as an Abeta transporter and the role of ABCB1 genotypes deserves further research. The investigated serum Abeta profile is probably not useful in the diagnosis of dementia.

Unusual Internal Rotation Coupling in the Microwave Spectrum of Pinacolone

NASA Astrophysics Data System (ADS)

Zhao, YueYue; Nguyen, Ha Vinh Lam; Stahl, Wolfgang; Hougen, Jon T.

2015-06-01

The molecular-beam Fourier-transform microwave spectrum of pinacolone (methyl tert-butyl ketone) has been measured in several regions between 2 and 40 GHz. Assignments of a large number of A and E transitions were confirmed by combination differences, but fits of the assigned spectrum using several torsion-rotation computer programs based on different models led to the unexpected conclusion that no existing program correctly captures the internal dynamics of this molecule. A second puzzle arose when it became clear that roughly half of the spectrum remained unassigned even after all predicted transitions were added to the assignment list. Quantum chemical calculations carried out at the MP2/6-311++G(d,p) level indicate that this molecule does not have a plane of symmetry at equilibrium, and that internal rotation of the light methyl group induces a large oscillatory motion of the heavy tert-butyl group from one side of the C_s saddle point to the other. The effect of this non-C_s equilibrium structure was modeled for J = 0 levels by a simple two-top torsional Hamiltonian, where magnitudes of the strong top-top coupling terms were determined directly from the ab initio two-dimensional potential surface. A plot of the resultant torsional levels on the same scale as a one-dimensional potential curve along the zig-zag path connecting the six (unequally spaced) minima bears a striking resemblance to the 1:2:1 splitting pattern of levels in an internal rotation problem with a six-fold barrier. A plot of the six minima closely resembles the potential surface for methylamine. This talk will focus on implications of these resemblances for future work.

A mixed odontogenic sarcoma: A challenging histopathologic case and brief review of the literature.

PubMed

Atarbashi-Moghadam, Saede; Lotfi, Ali; Mokhtari, Sepideh

2018-01-01

Ameloblastic fibro-odontosarcoma (AFOS) is an extremely rare malignant mixed odontogenic tumor. The ectomesenchymal part of the neoplasm shows malignancy, whereas the epithelial component is rather benign. In addition, small areas with deposition of enamel matrix and dentine material are seen. The rarity of this neoplasm and microscopic similarities with other malignant and benign tumors can lead to diagnostic problems. Here, we describe the histopathologic features of a new case of AFOS of the mandible in a 34-year-old female patient. It is essential for oral pathologists to be familiar with the microscopic features of this rare neoplasm to have a proper diagnosis. This is also the first reported case of AFOS that closely resembles osteosarcoma in some areas.

8- to 13-micron spectroscopy of Comet Levy 1990 XX

NASA Technical Reports Server (NTRS)

Lynch, David K.; Russell, Ray W.; Hackwell, John A.; Hanner, Martha S.; Hammel, Heidi B.

1992-01-01

The results are reported of IR spectroscopy of Comet Levy 1990 XX over a three-day period when the comet was about 1.54 AU from the sun roughly 70 days before perihelion. Comet Levy 1990 XX was bright, and for at least part of its inbound journey toward perihelion, active. At a distance of 1.54 AU from the sun it showed strong structured silicate emission with peaks or shoulders at 9.8 and 11.2 microns. These features resemble those of Comets P/Halley and Bradfield 1987 XXIX. The comet was variable in brightness. Specifically, the contrast of the silicate features changed by a factor of two relative to the continuum level and showed some evidence for a shape change as well.

Covariant C and O Isotope Trends in Some Terrestrial Carbonates and ALH 84001: Possible Linkage Through Similar Formation Processes

NASA Technical Reports Server (NTRS)

Volk, Kathryn E.; Niles, Paul B.; Socki, Richard A.

2011-01-01

Carbonate minerals found on the surface of Mars and in martian meteorites indicate that liquid water has played a significant role in the planet's history. These findings have raised questions regarding the history of the martian hydrosphere and atmosphere as well as the possibility of life. Sunset Crater, Arizona is a dry environment with relatively high evaporation and brief periods of precipitation. This environment resembles Mars and may make Sunset Crater a good analog to martian carbonates. In this study we sought to identify discrete micro-scale isotopic variation within the carbonate crusts in Sunset Crater to see if they resembled the micro-scale isotope variation found in ALH 84001 carbonates. Sunset Crater carbonate formation may be used as a martian analog and ultimately provide insight into carbonate formation in ALH 84001.

Description of a new species of Potamonautes MacLeay, 1838, from the iSimangaliso Wetland Park, South Africa

PubMed Central

Peer, Nasreen; Perissinotto, Renzo; Gouws, Gavin; Miranda, Nelson A.F.

2015-01-01

Abstract A new species of freshwater crab, Potamonautes isimangaliso sp. n., is described from the western shores of False Bay, Hluhluwe, within the iSimangaliso Wetland Park, South Africa. While bearing a superficial resemblance to Potamonautes lividus, the new species has been found to be genetically distinct, diverging from the former by 7.4–7.8% in mtDNA. Potamonautes isimangaliso most closely resembles Potamonautes lividus, but is distinguished by a unique suite of carapace characters, colouration, and size. The new species also lives in close association with oxygen-poor, fresh ephemeral pans, while the habitat of Potamonautes lividus is well above the surface water line of the closest water body. An updated identification key for the Potamonautes species of South Africa is provided. PMID:26019669

Photoexcitations in Polyacetylene.

DTIC Science & Technology

1981-11-11

Philadelphia, PA 19104 INov ~e!f M 81 Reproduction in whole or in part is permitted for any purpose of the United States Government Approved for public...substrates. Experiments utilized primarily the surface cell config- uration using ohmic contacts; similar results were obtained using sandwich cells ...resembles the photovoltaic quantum efficiency obtained from junction studies 5 with trans-(CH) . Thus, the photoresponse shown in Fig. 9 is genuine

Interdisciplinary scientist participation in the Phobos mission

NASA Technical Reports Server (NTRS)

1992-01-01

Data was acquired from VSK (2 wide-angle visible-NIR TV cameras at 0.4 to 0.6 micrometers and 0.8 to 1.1 micrometers, and a narrow-angle TV camera), KRFM (10-band UV-visible spectrometer at 0.3 to 0.6 micrometers and a 6-band radiometer at 5-50 micrometers), and ISM (a 128-channel NIR imaging spectrometer at 0.8 to 3 micrometers). These data provided improved mapping coverage of Phobos; improved mass, shape, and volume determinations, with the density shown to be lower than that of all known meteorites, suggesting a porous interior; evidence for a physically, spectrally and possibly compositionally heterogeneous surface; and proof that the spectral properties do not closely resemble those of unaltered carbonaceous chondrites, but show more resemblance to the spectra of altered mafic material. For Mars, the data show that the underlying rock type can be distinguished through the global dust cover; that the spectral properties and possibly composition vary laterally between and within the geologic provinces; that the surface physical properties vary laterally, and in many cases, the boundaries coincide with those of the geologic units; and the acquired data also demonstrate the value of reflectance spectroscopy and radiometry to the study of Martian geology.

Ion implantation modified stainless steel as a substrate for hydroxyapatite deposition. Part II. Biomimetic layer growth and characterization.

PubMed

Pramatarova, L; Pecheva, E; Krastev, V

2007-03-01

The interest in stainless steel as a material widely used in medicine and dentistry has stimulated extensive studies on improving its bone-bonding properties. AISI 316 stainless steel is modified by a sequential ion implantation of Ca and P ions (the basic ions of hydroxyapatite), and by Ca and P implantation and subsequent thermal treatment in air (600( composite function)C, 1 h). This paper investigates the ability of the as-modified surfaces to induce hydroxyapatite deposition by using a biomimetic approach, i.e. immersion in a supersaturated aqueous solution resembling the human blood plasma (the so-called simulated body fluid). We describe our experimental procedure and results, and discuss the physico-chemical properties of the deposed hydroxyapatite on the modified stainless steel surfaces. It is shown that the implantation of a selected combination of ions followed by the applied methodology of the sample soaking in the simulated body fluid yield the growth of hydroxyapatite layers with composition and structure resembling those of the bone apatite. The grown layers are found suitable for studying the process of mineral formation in nature (biomineralization).

THE ELECTRICAL ACTIVATION OF PASSIVE IRON WIRES IN NITRIC ACID

PubMed Central

Lillie, Ralph S.

1935-01-01

1. The relation between the E. M. F. and the minimal duration of an activating current has been determined for passive iron wires in nitric acid under varying conditions of concentration of acid, duration of recovery period, and presence of surface-action compounds. 2. The characteristic intensity-duration curves resemble those of irritable living tissues with moderate speeds of response to stimulation (with chronaxies of the order of 10 to 30σ). 3. The intensity of the current required for activation, as well as its minimal effective duration for a given intensity, increases rapidly with increase in the concentration of HNO3. 4. The responsiveness of the iron wire to brief currents is low immediately after activation and returns progressively to the original level during the immediately following period, at first rapidly and then slowly, following a time curve resembling the corresponding curve of living tissues during the relative refractory period. 5. Surface-active compounds decrease reversibly, to a degree dependent on concentration, the responsiveness of iron wires to brief currents. 6. Conditions are described under which the iron wire is activated by the break of an already flowing constant current. PMID:19872905

Nickel-hydrogen bipolar battery system

NASA Technical Reports Server (NTRS)

Thaller, L. H.

1982-01-01

Rechargeable nickel-hydrogen systems are described that more closely resemble a fuel cell system than a traditional nickel-cadmium battery pack. This was stimulated by the currently emerging requirements related to large manned and unmanned low Earth orbit applications. The resultant nickel-hydrogen battery system should have a number of features that would lead to improved reliability, reduced costs as well as superior energy density and cycle lives as compared to battery systems constructed from the current state-of-the-art nickel-hydrogen individual pressure vessel cells.

Mössbauer spectroscopy of Basal Ganglia

NASA Astrophysics Data System (ADS)

Miglierini, Marcel; Lančok, Adriana; Kopáni, Martin; Boča, Roman

2014-10-01

Chemical states, structural arrangement, and magnetic features of iron deposits in biological tissue of Basal Ganglia are characterized. The methods of SQUID magnetometry and electron microscopy are employed. 57Fe Mössbauer spectroscopy is used as a principal method of investigation. Though electron microscopy has unveiled robust crystals (1-3 μm in size) of iron oxides, they are not manifested in the corresponding 57Fe Mössbauer spectra. The latter were acquired at 300 K and 4.2 K and resemble ferritin-like behavior.

Disseminated Geosmithia argillacea infection in a German shepherd dog.

PubMed

Grant, David C; Sutton, Deanna A; Sandberg, Christina A; Tyler, Ronald D; Thompson, Elizabeth H; Romanelli, Anna M; Wickes, Brian L

2009-03-01

We report a systemic mycosis in a German Shepherd dog caused by Geosmithia argillacea. Although this etiologic agent microscopically resembles a Penicillium species, and is histopathologically compatible with members of the genus Aspergillus, morphologic features and molecular characterization clearly separate it from these genera. This appears to be the first report of disseminated disease by this species in humans or animals. In vitro antifungal susceptibility testing suggests resistance to amphotericin B and voriconazole and susceptibility to caspofungin, itraconazole, and posaconazole.

Active and hibernating turbulence in minimal channel flow of newtonian and polymeric fluids.

PubMed

Xi, Li; Graham, Michael D

2010-05-28

Turbulent channel flow of drag-reducing polymer solutions is simulated in minimal flow geometries. Even in the Newtonian limit, we find intervals of "hibernating" turbulence that display many features of the universal maximum drag reduction asymptote observed in polymer solutions: weak streamwise vortices, nearly nonexistent streamwise variations, and a mean velocity gradient that quantitatively matches experiments. As viscoelasticity increases, the frequency of these intervals also increases, while the intervals themselves are unchanged, leading to flows that increasingly resemble maximum drag reduction.

Apoptosis: a basic pathological reaction of injured neonatal muscle.

PubMed

Fidziańska, A; Kamińska, A

1991-01-01

A light and electron microscopic study of immature muscle cell degeneration induced by bupivacaine (BPVC) was performed. The pattern of muscle cell death is related to muscle maturity; in newborn rats, cell death has the morphology of apoptosis, whereas in the older animals muscle cell death resembles cell necrosis and the ultrastructural feature of these changes are essentially the same as those described in adult muscle. The ability to undergo apoptosis in response to a pathological stimulus is a common effector mechanism of immature muscle.

Mössbauer spectroscopy of Basal Ganglia

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

Miglierini, Marcel, E-mail: marcel.miglierini@stuba.sk; Lančok, Adriana; Kopáni, Martin

2014-10-27

Chemical states, structural arrangement, and magnetic features of iron deposits in biological tissue of Basal Ganglia are characterized. The methods of SQUID magnetometry and electron microscopy are employed. {sup 57}Fe Mössbauer spectroscopy is used as a principal method of investigation. Though electron microscopy has unveiled robust crystals (1-3 μm in size) of iron oxides, they are not manifested in the corresponding {sup 57}Fe Mössbauer spectra. The latter were acquired at 300 K and 4.2 K and resemble ferritin-like behavior.

Quark Hadron Duality - Recent Jefferson Lab Results

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

Niculescu, Maria Ioana

2016-08-01

The duality between the partonic and hadronic descriptions of electron--nucleon scattering is a remarkable feature of nuclear interactions. When averaged over appropriate energy intervals the cross section at low energy which is dominated by nucleon resonances resembles the smooth behavior expected from perturbative QCD. Recent Jefferson Lab results indicate that quark-hadron duality is present in a variety of observables, not just the proton F2 structure function. An overview of recent results, especially local quark-hadron duality on the neutron, are presented here.

Crystal Structure of the Extracellular Cholinesterase-Like Domain from Neuroligin-2

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

Koehnke,J.; Jin, X.; Budreck, E.

Neuroligins (NLs) are catalytically inactive members of a family of cholinesterase-like transmembrane proteins that mediate cell adhesion at neuronal synapses. Postsynaptic neuroligins engage in Ca2+-dependent transsynaptic interactions via their extracellular cholinesterase domain with presynaptic neurexins (NRXs). These interactions may be regulated by two short splice insertions (termed A and B) in the NL cholinesterase domain. Here, we present the 3.3- Angstroms crystal structure of the ectodomain from NL2 containing splice insertion A (NL2A). The overall structure of NL2A resembles that of cholinesterases, but several structural features are unique to the NL proteins. First, structural elements surrounding the esterase active-site regionmore » differ significantly between active esterases and NL2A. On the opposite surface of the NL2A molecule, the positions of the A and B splice insertions identify a candidate NRX interaction site of the NL protein. Finally, sequence comparisons of NL isoforms allow for mapping the location of residues of previously identified mutations in NL3 and NL4 found in patients with autism spectrum disorders. Overall, the NL2 structure promises to provide a valuable model for dissecting NL isoform- and synapse-specific functions.« less

Wallet Neuritis - An Example of Peripheral Sensitization.

PubMed

Siddiq, Md Abu Bakar; Jahan, Israt; Masihuzzaman, Sam

2017-03-09

Wallet neuritis is an example of extra-spinal tunnel neuropathy concerning sciatic nerve. Its clinical appearance often gets confused with sciatica of lumbar spine origin. Wallet-induced chronic sciatic nerve constriction produces gluteal and ipsilateral lower extremity pain, tingling, and burning sensation. It was Lutz, first describing credit-card wallet sciatica in an Attorney, surfaced on Journal of American Medical Association (JAMA), 1978; however, the condition has not been well-studied in various other occupations. In this write-up, I take the privilege of demonstrating wallet neuritis as an example of peripheral sensitization in three different professionals namely specialist doctor, driver, and banker first time in Bangladesh. All the three patients demonstrated about aggravated gluteal pain with radiation on the ipsilateral lower extremity while remained seated on heavy wallet for a while, fortunately improved discontinuing such stuff with. Alongside, radical wallectomy, piriformis stretching exercise on the affected side had also been recommended and found worthy in terms of pain relief. long-standing use of rear pocket wallet may compress and sensitize ipsilateral sciatic nerve, generating features resembling lumbago sciatica; thereby, remains a source of patients' misery and diagnostic illusion for pain physicians as well. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Molecular characterization of neoplastic and normal "sister" lymphoblastoid B-cell lines from chronic lymphocytic leukemia.

PubMed

Lanemo Myhrinder, Anna; Hellqvist, Eva; Bergh, Ann-Charlotte; Jansson, Mattias; Nilsson, Kenneth; Hultman, Per; Jonasson, Jon; Buhl, Anne Mette; Bredo Pedersen, Lone; Jurlander, Jesper; Klein, Eva; Weit, Nicole; Herling, Marco; Rosenquist, Richard; Rosén, Anders

2013-08-01

Chronic lymphocytic leukemia (CLL) B-cells resemble self-renewing CD5 + B-cells carrying auto/xeno-antigen-reactive B-cell receptors (BCRs) and multiple innate pattern-recognition receptors, such as Toll-like receptors and scavenger receptors. Integration of signals from BCRs with multiple surface membrane receptors determines whether the cells will be proliferating, anergic or apoptotic. To better understand the role of antigen in leukemogenesis, CLL cell lines producing monoclonal antibodies (mAbs) will facilitate structural analysis of antigens and supply DNA for genetic studies. We present here a comprehensive genotypic and phenotypic characterization of available CLL and normal B-cell-derived lymphoblastoid cell lines (LCLs) from the same individuals (n = 17). Authenticity and verification studies of CLL-patient origin were done by IGHV sequencing, fluorescence in situ hybridization (FISH) and DNA/short tandem repeat (STR) fingerprinting. Innate B-cell features, i.e. natural Ab production and CD5 receptors, were present in most CLL cell lines, but in none of the normal LCLs. This panel of immortalized CLL-derived cell lines is a valuable reference representing a renewable source of authentic Abs and DNA.

Neuronal encoding of ultrasonic sound by a fish.

PubMed

Plachta, Dennis T T; Song, Jiakun; Halvorsen, Michele B; Popper, Arthur N

2004-06-01

Many species of odontocete cetaceans (toothed whales) use high-frequency clicks (60-170 kHz) to identify objects in their environment, including potential prey. Behavioral studies have shown that American shad, Alosa sapidissima, can detect ultrasonic signals similar to those of odontocetes that are potentially their predators. American shad also show strong escape behavior in response to ultrasonic pulses between 70 and 110 kHz and can determine the location of the sound source at least in the horizontal plane. The present study examines physiological aspects of ultrasound detection by American shad and provides the first insights into the neural encoding of ultrasound signals in any nonmammalian vertebrate. The recordings were obtained by penetration through the cerebellar surface. All but two units responded exclusively to ultrasound. Ultrasound-sensitive units did not phase-couple to any stimulus frequency. Some units resembled the response of constant latency neurons found in the ventral nucleus of the lateral lemniscus of bats. We suggest that ultrasonic and sonic signals are processed along different pathways in Alosa. The ultrasonic pathway in Alosa appears to be a feature detector that is likely to be adapted (e.g., frequency, intensity) to odontocete echolocation signals.

Three-dimensional boundary layer stability and transition

NASA Technical Reports Server (NTRS)

Malik, M. R.; Li, F.

1992-01-01

Nonparallel and nonlinear stability of a three-dimensional boundary layer, subject to crossflow instability, is investigated using parabolized stability equations (PSEs). Both traveling and stationary disturbances are considered and nonparallel effect on crossflow instability is found to be destabilizing. Our linear PSE results for stationary disturbances agree well with the results from direct solution of Navier-Stokes equations obtained by Spalart (1989). Nonlinear calculations have been carried out for stationary vortices and the computed wall vorticity pattern results in streamwise streaks which resemble remarkably well with the surface oil-flow visualizations in swept-wing experiments. Other features of the stationary vortex development (half-mushroom structure, inflected velocity profiles, vortex doubling, etc.) are also captured in our nonlinear calculations. Nonlinear interaction of the stationary amplitude of the stationary vortex is large as compared to the traveling mode, and the stationary vortex dominates most of the downstream development. When the two modes have the same initial amplitude, the traveling mode dominates the downstream development owing to its higher growth rate, and there is a tendency for the stationary mode to be suppressed. The effect of nonlinear wave development on the skin-friction coefficient is also computed.

The morphogenic features of otoconia during larval development of Cynops pyrrhogaster, the Japanese red-bellied newt

NASA Technical Reports Server (NTRS)

Steyger, P. S.; Wiederhold, M. L.; Batten, J.

1995-01-01

Otoconia are calcified protein matrices within the gravity-sensing organs of the vertebrate vestibular system. Mammalian otoconia are barrel-shaped with triplanar facets at each end. Reptilian otoconia are commonly prismatic or fusiform in shape. Amphibians have all three otoconial morphologies, barrel-shaped otoconia within the utricle, with prismatic and fusiform otoconia in the saccule. Scanning electron microscopy revealed a sequential appearance of all three otoconial morphologies during larval development of the newt, Cynops pyrrhogaster. The first otoconia appear within a single, developing otolith, and some resemble adult barrel-shaped otoconia. As the larvae hatch, around stages 39-42, the single otolith divides into two anatomically separate regions, the utricle and saccule, and both contain otoconia similar to those seen in the single otolith. Throughout development, these otoconia may have variable morphologies, with serrated surfaces, or circumferential striations with either separated facets or adjacent facets in the triplanar end-regions. Small fusiform otoconia occur later, at stage 51, and only in the saccule. Prismatic otoconia appear later still, at stage 55, and again only in the saccule. Thus, although prismatic otoconia are the most numerous in adult newts, it is the last vestibular otoconial morphology to be expressed.

Crystal structure of the extracellular cholinesterase-like domain from neuroligin-2

PubMed Central

Koehnke, Jesko; Jin, Xiangshu; Budreck, Elaine C.; Posy, Shoshana; Scheiffele, Peter; Honig, Barry; Shapiro, Lawrence

2008-01-01

Neuroligins (NLs) are catalytically inactive members of a family of cholinesterase-like transmembrane proteins that mediate cell adhesion at neuronal synapses. Postsynaptic neuroligins engage in Ca2+-dependent transsynaptic interactions via their extracellular cholinesterase domain with presynaptic neurexins (NRXs). These interactions may be regulated by two short splice insertions (termed A and B) in the NL cholinesterase domain. Here, we present the 3.3-Å crystal structure of the ectodomain from NL2 containing splice insertion A (NL2A). The overall structure of NL2A resembles that of cholinesterases, but several structural features are unique to the NL proteins. First, structural elements surrounding the esterase active-site region differ significantly between active esterases and NL2A. On the opposite surface of the NL2A molecule, the positions of the A and B splice insertions identify a candidate NRX interaction site of the NL protein. Finally, sequence comparisons of NL isoforms allow for mapping the location of residues of previously identified mutations in NL3 and NL4 found in patients with autism spectrum disorders. Overall, the NL2 structure promises to provide a valuable model for dissecting NL isoform- and synapse-specific functions. PMID:18250328

Embedded biofilm, a new biofilm model based on the embedded growth of bacteria.

PubMed

Jung, Yong-Gyun; Choi, Jungil; Kim, Soo-Kyoung; Lee, Joon-Hee; Kwon, Sunghoon

2015-01-01

A variety of systems have been developed to study biofilm formation. However, most systems are based on the surface-attached growth of microbes under shear stress. In this study, we designed a microfluidic channel device, called a microfluidic agarose channel (MAC), and found that microbial cells in the MAC system formed an embedded cell aggregative structure (ECAS). ECASs were generated from the embedded growth of bacterial cells in an agarose matrix and better mimicked the clinical environment of biofilms formed within mucus or host tissue under shear-free conditions. ECASs were developed with the production of extracellular polymeric substances (EPS), the most important feature of biofilms, and eventually burst to release planktonic cells, which resembles the full developmental cycle of biofilms. Chemical and genetic effects have also confirmed that ECASs are a type of biofilm. Unlike the conventional biofilms formed in the flow cell model system, this embedded-type biofilm completes the developmental cycle in only 9 to 12 h and can easily be observed with ordinary microscopes. We suggest that ECASs are a type of biofilm and that the MAC is a system for observing biofilm formation. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

The marmoset monkey as a model for visual neuroscience

PubMed Central

Mitchell, Jude F.; Leopold, David A.

2015-01-01

The common marmoset (Callithrix jacchus) has been valuable as a primate model in biomedical research. Interest in this species has grown recently, in part due to the successful demonstration of transgenic marmosets. Here we examine the prospects of the marmoset model for visual neuroscience research, adopting a comparative framework to place the marmoset within a broader evolutionary context. The marmoset’s small brain bears most of the organizational features of other primates, and its smooth surface offers practical advantages over the macaque for areal mapping, laminar electrode penetration, and two-photon and optical imaging. Behaviorally, marmosets are more limited at performing regimented psychophysical tasks, but do readily accept the head restraint that is necessary for accurate eye tracking and neurophysiology, and can perform simple discriminations. Their natural gaze behavior closely resembles that of other primates, with a tendency to focus on objects of social interest including faces. Their immaturity at birth and routine twinning also makes them ideal for the study of postnatal visual development. These experimental factors, together with the theoretical advantages inherent in comparing anatomy, physiology, and behavior across related species, make the marmoset an excellent model for visual neuroscience. PMID:25683292

Eroded Scallops with Layers

NASA Image and Video Library

2017-01-09

The western Utopia Planitia in the Northern mid-latitudes of Mars is marked by a peculiar type of depression with scalloped edges and by a network of polygonal fractures. The scalloped depressions are typical features; a smooth layered terrain located between 40 and 60 degrees in both hemispheres. Scalloped depressions probably form by removal of ice-rich subsurface material by sublimation (ice transforming directly from a solid to a gaseous state), a process that may still be active today. Isolated scalloped depressions generally have a steep pole-facing scarp and a gentler equator-facing slope. This asymmetry is interpreted as being the result of difference in solar heating. Scalloped depressions may coalesce, leading to the formation of large areas of pitted terrain. The polygonal pattern of fractures resembles permafrost polygons that form in terrestrial polar and high alpine regions by seasonal-to-annual contraction of the permafrost (permanently frozen ground). On Earth, such polygons indicate the presence of ground ice. These landforms most likely show that sub-surface ice is present or has been present geologically recently at these latitudes, and they may slowly be continuing their development at the present time. http://photojournal.jpl.nasa.gov/catalog/PIA13485

Multiple Gaps in the Disk of the Class I Protostar GY 91

NASA Astrophysics Data System (ADS)

Sheehan, Patrick D.; Eisner, Josh A.

2018-04-01

We present the highest spatial resolution Atacama Large Millimeter/submillimeter Array (ALMA) observations to date of the Class I protostar GY 91 in the ρ Ophiuchus L1688 molecular cloud complex. Our 870 μm and 3 mm dust continuum maps show that the GY 91 disk has a radius of ∼80 au, and an inclination of ∼40°, but most interestingly that the disk has three dark lanes located at 10, 40, and 70 au. We model these features assuming they are gaps in the disk surface density profile and find that their widths are 7, 30, and 10 au. These gaps bear a striking resemblance to the gaps seen in the HL Tau disk, suggesting that there may be Saturn-mass planets hiding in the disk. To constrain the relative ages of GY 91 and HL Tau, we also model the disk and envelope of HL Tau and find that they are of similar ages, although GY 91 may be younger. Although snow lines and magnetic dead zones can also produce dark lanes, if planets are indeed carving these gaps then Saturn-mass planets must form within the first ∼0.5 Myr of the lifetime of protoplanetary disks.

Europa Ice Rafts

NASA Technical Reports Server (NTRS)

1997-01-01

This high resolution image shows the ice-rich crust of Europa, one of the moons of Jupiter. Seen here are crustal plates ranging up to 13 kilometers (8 miles) across, which have been broken apart and 'rafted' into new positions, superficially resembling the disruption of pack-ice on polar seas during spring thaws on Earth. The size and geometry of these features suggest that motion was enabled by ice-crusted water or soft ice close to the surface at the time of disruption.

The area shown is about 34 kilometers by 42 kilometers (21 miles by 26 miles), centered at 9.4 degrees north latitude, 274 degrees west longitude, and the resolution is 54 meters (59 yards). This picture was taken by the Solid State Imaging system on board the Galileo spacecraft on February 20, 1997, from a distance of 5,340 kilometers (3,320 miles) during the spacecraft's close flyby of Europa.

The Jet Propulsion Laboratory, Pasadena, CA, manages the mission for NASA's Office of Space Science, Washington D.C. This image and other images and data received from Galileo are posted on the World Wide Web Galileo mission home page at: http://galileo.jpl.nasa.gov.

The Nonbarred Double-Ringed Galaxy, PGC 1000714

NASA Astrophysics Data System (ADS)

Seigar, Marc; Mutlu Pakdil, Burcin; Mangedarage, Mithila; Treuthardt, Patrick M.

2017-01-01

Hoag-type galaxies are rare peculiar systems which bear strong resemblance to Hoag's Object with an elliptical-like core, a detached outer ring, and no signs of a bar or stellar disk. They represent extreme cases and help us understand the formation of galaxies in general by providing clues on formation mechanisms. The nature of outer rings in Hoag-type galaxies is still debated and may be related either to slow secular evolution, such as dissolution of a barlike structure or to environmental processes, such as galaxy-galaxy interactions or gas infall. Due to a fairly superficial resemblance to Hoag's Object, PGC 1000714 is a good target for detailed study of the peculiar structure of this type. We present the first photometric study of PGC 1000714 that has not yet been described in the literature. Our aim is to evaluate its structure and properties as well as understand the origin of outer rings in such galaxies. Surface photometry of the central body is performed using near-UV, BVRI and JHK images. Based on the photometric data, the nearly round central body follows a de Vaucouleurs profile almost all the way to the center. The detailed photometry reveals a reddish inner ring-shaped structure that shares the same center as the central body. However, no sign of a bar or stellar disk is detected. The outer ring appears as a bump in the surface brightness profile with a peak brightness of 25.8 mag/arcsec^{2} in the B-band and shows no sharp outer boundary. By reconstructing the observed SED for the central body and the rings, we recover the stellar population properties of the galaxy components. Our work suggests different formation histories for the inner and outer rings. We rule out the secular evolution model as being a formation mechanism for the outer ring. The colors of the outer ring are consistent with a feature that may have experienced a burst of star formation due to a possible recent accretion event. In addition, our work supports that the central body may be formed by a relatively dry major merger or in a single, short and highly effective star formation burst, and the inner ring may be formed as a result of intergalactic medium accretion or secular evolution of a possible gaseous disk

Lipid Clustering Correlates with Membrane Curvature as Revealed by Molecular Simulations of Complex Lipid Bilayers

PubMed Central

Koldsø, Heidi; Shorthouse, David; Hélie, Jean; Sansom, Mark S. P.

2014-01-01

Cell membranes are complex multicomponent systems, which are highly heterogeneous in the lipid distribution and composition. To date, most molecular simulations have focussed on relatively simple lipid compositions, helping to inform our understanding of in vitro experimental studies. Here we describe on simulations of complex asymmetric plasma membrane model, which contains seven different lipids species including the glycolipid GM3 in the outer leaflet and the anionic lipid, phosphatidylinositol 4,5-bisphophate (PIP2), in the inner leaflet. Plasma membrane models consisting of 1500 lipids and resembling the in vivo composition were constructed and simulations were run for 5 µs. In these simulations the most striking feature was the formation of nano-clusters of GM3 within the outer leaflet. In simulations of protein interactions within a plasma membrane model, GM3, PIP2, and cholesterol all formed favorable interactions with the model α-helical protein. A larger scale simulation of a model plasma membrane containing 6000 lipid molecules revealed correlations between curvature of the bilayer surface and clustering of lipid molecules. In particular, the concave (when viewed from the extracellular side) regions of the bilayer surface were locally enriched in GM3. In summary, these simulations explore the nanoscale dynamics of model bilayers which mimic the in vivo lipid composition of mammalian plasma membranes, revealing emergent nanoscale membrane organization which may be coupled both to fluctuations in local membrane geometry and to interactions with proteins. PMID:25340788

Crystal structure and biochemical features of dye-decolorizing peroxidase YfeX from Escherichia coli O157 Asp{sup 143} and Arg{sup 232} play divergent roles toward different substrates

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

Liu, Xiuhua; Yuan, Zenglin; Wang, Jiaxu

YfeX from Escherichia coli O157 is a bacterial dye-decolorizing peroxidase that represents both dye-decoloring activity and typical peroxidase activity. We reported the crystal structure of YfeX bound to heme at 2.09 Å resolution. The YfeX monomer resembles a ferredoxin-like fold and contains two domains. The three conserved residues surrounding the heme group are His{sup 215}, Asp{sup 143} and Arg{sup 232}. His{sup 215} functions as the proximal axial ligand of the heme iron atom. Biochemical data show that the catalytic significance of the conserved Asp{sup 143} and Arg{sup 232} depends on the substrate types and that YfeX may adopt various catalytic mechanismsmore » toward divergent substrates. In addition, it is observed that an access tunnel spans from the protein molecular surface to the heme distal region, it serves as the passageway for the entrance and binding of the H{sub 2}O{sub 2}. - Highlights: • We determined the crystal structure of YfeX bound to heme at 2.09 Å resolution. • The conserved Asp{sup 143} and Arg{sup 232} play different roles toward divergent substrates. • The H{sub 2}O{sub 2} access tunnel spans from the protein molecular surface to the heme distal region.« less

Glial architecture of the ghost shark (Callorhinchus milii, Holocephali, Chondrichthyes) as revealed by different immunohistochemical markers.

PubMed

Ari, Csilla; Kálmán, Mihály

2008-09-15

This article presents the first study on the glial architecture of a representative species of Holocephali, Callorhinchus milii (ghost shark). Holocephali are a small subclass of Chondrichthyes, with only a few extant genera, and those are considered to have a brain organization more similar to squalomorph sharks than to galeomorph sharks, skates, and rays. Three different astroglial markers--glial fibrillary acidic protein, S-100 protein, and glutamine synthetase (GS)--were investigated by immunohistochemical methods, applying both diaminobenzidine (DAB) and fluorescent techniques. They revealed similar glial structures, although most of them were detected by immunohistochemical reaction against GS and visualized by DAB. The predominant elements were radial ependymoglia spanning the area between the ventricular and meningeal surfaces, as in squalomorph sharks. Other similar features were the light appearance of myelinated neural tracts devoid of immunoreactivity, and the glial architecture of the reticular formation of the brain stem, cerebellum, and tectum, the latter with recognizable layers. The immunoreactivity of the vascular walls was similar; however, it is believed that different cell types form the blood-brain barrier in chimeras and in elasmobranchs. Some glial structures, however, resembled those of skates, rays, and galeomorph sharks. In C. milii astrocyte-like elements were observed in the telencephalon, using GS and S-100, although typical astrocyte-rich regions were not found. In some areas, especially the telencephalon, not only endfeet but also cell bodies were observed to be attached to the meningeal surface, with processes extending into the brain substance.

Lipid clustering correlates with membrane curvature as revealed by molecular simulations of complex lipid bilayers.

PubMed

Koldsø, Heidi; Shorthouse, David; Hélie, Jean; Sansom, Mark S P

2014-10-01

Cell membranes are complex multicomponent systems, which are highly heterogeneous in the lipid distribution and composition. To date, most molecular simulations have focussed on relatively simple lipid compositions, helping to inform our understanding of in vitro experimental studies. Here we describe on simulations of complex asymmetric plasma membrane model, which contains seven different lipids species including the glycolipid GM3 in the outer leaflet and the anionic lipid, phosphatidylinositol 4,5-bisphophate (PIP2), in the inner leaflet. Plasma membrane models consisting of 1500 lipids and resembling the in vivo composition were constructed and simulations were run for 5 µs. In these simulations the most striking feature was the formation of nano-clusters of GM3 within the outer leaflet. In simulations of protein interactions within a plasma membrane model, GM3, PIP2, and cholesterol all formed favorable interactions with the model α-helical protein. A larger scale simulation of a model plasma membrane containing 6000 lipid molecules revealed correlations between curvature of the bilayer surface and clustering of lipid molecules. In particular, the concave (when viewed from the extracellular side) regions of the bilayer surface were locally enriched in GM3. In summary, these simulations explore the nanoscale dynamics of model bilayers which mimic the in vivo lipid composition of mammalian plasma membranes, revealing emergent nanoscale membrane organization which may be coupled both to fluctuations in local membrane geometry and to interactions with proteins.

A discrete model of Ostwald ripening based on multiple pairwise interactions

NASA Astrophysics Data System (ADS)

Di Nunzio, Paolo Emilio

2018-06-01

A discrete multi-particle model of Ostwald ripening based on direct pairwise interactions is developed for particles with incoherent interfaces as an alternative to the classical LSW mean field theory. The rate of matter exchange depends on the average surface-to-surface interparticle distance, a characteristic feature of the system which naturally incorporates the effect of volume fraction of second phase. The multi-particle diffusion is described through the definition of an interaction volume containing all the particles involved in the exchange of solute. At small volume fractions this is proportional to the size of the central particle, at higher volume fractions it gradually reduces as a consequence of diffusion screening described on a geometrical basis. The topological noise present in real systems is also included. For volume fractions below about 0.1 the model predicts broad and right-skewed stationary size distributions resembling a lognormal function. Above this value, a transition to sharper, more symmetrical but still right-skewed shapes occurs. An excellent agreement with experiments is obtained for 3D particle size distributions of solid-solid and solid-liquid systems with volume fraction 0.07, 0.30, 0.52 and 0.74. The kinetic constant of the model depends on the cube root of volume fraction up to about 0.1, then increases rapidly with an upward concavity. It is in good agreement with the available literature data on solid-liquid mixtures in the volume fraction range from 0.20 to about 0.75.

Surface Composition Near the Trailing Hemisphere Apex on Europa: The Manannán Impact Crater and Neighboring Terrain

NASA Astrophysics Data System (ADS)

Dalton, J. B.; Prockter, L. M.; Shirley, J. H.; Kamp, L.; Phillips, C. B.; Valenti, M.

2012-12-01

The Manannán impact crater and surrounding areas were imaged by Galileo's Near Infrared Mapping Spectrometer (NIMS) during the C3 orbital encounter. We have applied a linear mixture model based on cryogenic infrared reflectance spectroscopy to a "despiked" version of this NIMS observation (C3ENLINEA01A) to estimate abundances of sulfuric acid hydrate, hydrated sulfate salts, water ice and brines in surface exposures. Here we supplement our previously reported abundance estimates (Dalton et al., 2011) with additional results from our ongoing investigation. New geologic mapping precisely registered to the NIMS observation allows the extraction of high-quality near-infrared spectra specific to individual geologic units and morphological features. Detailed high resolution geologic mapping indicates the likely presence of extensive deposits of impact melt materials largely filling the crater floor (Moore et al. 2001), together with surrounding continuous ejecta deposits that may have been excavated from Europa's interior. We find that the crater floor and nearby ejecta exhibit low sulfuric acid abundance relative to the surroundings, with the abundance increasing with radial distance. Where the ejecta begins to thin and break up, the spectral mixture resembles a combination of pre-existing, high-acid-content materials and cleaner, excavated water ice. Several geologic units exhibit significantly lower sulfuric acid hydrate than expected for this region near the trailing hemisphere apex, varying from 53-64 wt% over the observation. This suggests that these surface units have received a reduced cumulative radiation dose (electrons and ions) compared to nearby terrain; this in turn implies geologic youth. We will present model compositions for several of Manannán's key stratigraphic units, including the crater floor deposits and the adjacent chaos and linea. We will interpret these results in the context of ongoing investigations of the interplay of exogenic and endogenic influences on the surface composition of Europa. This work was performed at the Jet Propulsion Laboratory-California Institute of Technology, Johns Hopkins University-Applied Physics Laboratory, and the SETI Institute under a contract with NASA. Support by NASA's Outer Planets Research program is gratefully acknowledged. Dalton, III, J.B., Prockter, L.M., Shirley, J.H., Kamp, L.W., Phillips, C., and Valenti, M., The Manannán Impact Crater on Europa: Determination of Surface Compositions of Key Stratigraphic Units, EOS Trans. AGU, Fall Meeting, #P14B-06, San Francisco, 2011. Moore, J. M. and 25 others 2001. Impact Features on Europa: Results of the Galileo Europa Mission (GEM), Icarus 151, 93-111.

Infrared spectroscopic characterization of the low-albedo materials on Iapetus

NASA Astrophysics Data System (ADS)

Dalle Ore, Cristina Morea; Cruikshank, Dale P.; Clark, Roger N.

2012-11-01

Iapetus, one of the large satellites of Saturn, has been studied over the centuries for its signature brightness contrast, light on one side and dark on the opposite. It has recently been suggested that the dark material is a combination of native and exogenous materials with distinct histories. We present an analysis of parts of the Cassini Regio, the darkest region on the leading hemisphere of Iapetus, focusing on the hydrocarbon signature with a view to detect and investigate differences in the material(s). We find variations in the hydrocarbon bands with geographic location, one type predominantly located on the leading hemisphere. A comparison with the equivalent spectral features on Phoebe and Hyperion reveals a predictable resemblance between the leading hemisphere material and Phoebe and an unexpected likeness between Hyperion’s darkest material and Iapetus’ trailing hemisphere surface. An analysis of the slope in the visible part of the spectrum is strongly affected by a rise in the continuum (∼0.35-0.65 μm) attributed to Rayleigh scattering from nano-size particles on the surface. The continuum rise varies in strength with the albedo and H2O ice content, and when it is properly accounted for, the overall slope in all the identified spectral units is the same over the interval 0.35-2.3 μm, independent of albedo or ice abundance. The interpretation of current and previous results offers two different scenarios illustrated by the presence of one vs. two dark materials distributed over the Iapetus surface. We describe the scenarios and their implications. The appearance of the aromatic and aliphatic absorption bands together in their measured relative strengths makes this spectral signature unique, and thus enables the comparison among the three satellites.

Pathology of carcinoma in situ of the urinary bladder and related lesions.

PubMed

Farrow, G M

1992-01-01

In the United States, nearly all cases of bladder cancer are of the transitional cell type, and epidemiological evidence indicates that among these, approximately 80% present initially as more or less well-differentiated, superficial papillary neoplasms with a tendency for multifocal or diffuse involvement of the urothelial surface and/or recurrent tumor episodes, but with limited potential for invasive growth or a lethal outcome. Bladder tumors with lethal potential generally begin as poorly differentiated, sessile growths that are usually invasive at first diagnosis. Carcinoma in situ is a change that must be elicited among intact surface cells before progressive proliferation results in a tumor mass. Evidence for such an association is both temporal and spatial. Since most transitional cell carcinomas begin as well-differentiated tumors, i.e., resembling normal urothelium, recognition of early neoplastic alteration before a papillary structure forms is unlikely and most of the evidence is spatial based upon urothelial changes adjacent to papillary tumors. The morphologic definition of carcinoma in situ is arbitrary and generally defined as a total replacement of the urothelial surface by cells which bear morphologic features of carcinoma, but which lack architectural alteration other than an increase in the number of cell layers, i.e., a flat lesion. The Union Internationále Contra Cancer/American Joint Committee on Cancer (UICC/AJCC) staging scheme for bladder cancer distinguishes non-invasive papillary growths as Ta and carcinoma in situ as Tis. Because detection of carcinoma in situ, either by cytology or biopsy, depends upon recognizable malignant morphologic characteristics, studies of the lesion tend to be limited to the higher grade or more anaplastic examples.(ABSTRACT TRUNCATED AT 250 WORDS)

A CANDELS-3D-HST synergy: Resolved Star Formation Patterns at 0.7 < z < 1.5

NASA Astrophysics Data System (ADS)

Wuyts, Stijn; Förster Schreiber, Natascha M.; Nelson, Erica J.; van Dokkum, Pieter G.; Brammer, Gabe; Chang, Yu-Yen; Faber, Sandra M.; Ferguson, Henry C.; Franx, Marijn; Fumagalli, Mattia; Genzel, Reinhard; Grogin, Norman A.; Kocevski, Dale D.; Koekemoer, Anton M.; Lundgren, Britt; Lutz, Dieter; McGrath, Elizabeth J.; Momcheva, Ivelina; Rosario, David; Skelton, Rosalind E.; Tacconi, Linda J.; van der Wel, Arjen; Whitaker, Katherine E.

2013-12-01

We analyze the resolved stellar populations of 473 massive star-forming galaxies at 0.7 < z < 1.5, with multi-wavelength broadband imaging from CANDELS and Hα surface brightness profiles at the same kiloparsec resolution from 3D-HST. Together, this unique data set sheds light on how the assembled stellar mass is distributed within galaxies, and where new stars are being formed. We find the Hα morphologies to resemble more closely those observed in the ACS I band than in the WFC3 H band, especially for the larger systems. We next derive a novel prescription for Hα dust corrections, which accounts for extra extinction toward H II regions. The prescription leads to consistent star formation rate (SFR) estimates and reproduces the observed relation between the Hα/UV luminosity ratio and visual extinction, on both a pixel-by-pixel and a galaxy-integrated level. We find the surface density of star formation to correlate with the surface density of assembled stellar mass for spatially resolved regions within galaxies, akin to the so-called "main sequence of star formation" established on a galaxy-integrated level. Deviations from this relation toward lower equivalent widths are found in the inner regions of galaxies. Clumps and spiral features, on the other hand, are associated with enhanced Hα equivalent widths, bluer colors, and higher specific SFRs compared to the underlying disk. Their Hα/UV luminosity ratio is lower than that of the underlying disk, suggesting that the ACS clump selection preferentially picks up those regions of elevated star formation activity that are the least obscured by dust. Our analysis emphasizes that monochromatic studies of galaxy structure can be severely limited by mass-to-light ratio variations due to dust and spatially inhomogeneous star formation histories.

Theoretical properties of Omega-loops in the convective zone of the Sun. 3: Extended updrafts

NASA Technical Reports Server (NTRS)

Parker, E. N.

1995-01-01

It was pointed out in an earlier paper that the continuing emergence of Omega-loops at localized sites on the surface of the Sun indicates a continuing updraft at those sites. The updraft evidently extends all the way from the base of the convective zone to somewhat near (approximately 10(exp 9)cm) the surface. We pointed out that such updrafts enhance the convective heat transport to the surface, accounting for a major part of the increased solar brightness or irradiance during times of solar activity. The problem is to work out, as much as possible, the dynamical nature of the extended updrafts, initiated as the wakes of successive rising Omega-loops and driven therafter by the convective forces. The question is, does the updraft take on a long-lived columnar form of its own, or does it never devlop beyond a sequence of rising wakes, resembling beads on a string? The dynamics of a columnar updraft is complicated by both the large Reynolds number and the strong stratication of the atmosphere, and by a total lack of direct observational information. Extended slender updrafts are not a spontaneous occurrence in numerical simulations of thermal convection in a stratified atmosphere, although slender concentrated downdrafts commonly occur. This paper examines several aspects of a columnar updrft in a convective atmosphere under various idealized circumstances to investigate to what extent that state can be maintained against the diminishing vorticity and expansion in the updraft. It appears that the successive passage of Omega-loops from the bottom to the top of the convective zone is an essential feature of the continuing existence of the updraft.

Hybrid finite-difference/lattice Boltzmann simulations of microchannel and nanochannel acoustic streaming driven by surface acoustic waves

NASA Astrophysics Data System (ADS)

Tan, Ming K.; Yeo, Leslie Y.

2018-04-01

A two-dimensional hybrid numerical method that allows full coupling of the elastic motion in a piezoelectric solid (modeled using a finite-difference time-domain technique) with the resultant compressional flow in a fluid (simulated using a lattice Boltzmann scheme) is developed to study the acoustic streaming that arises in both microchannels and nanochannels under surface acoustic wave (SAW) excitation. In addition to verifying the model through a comparison of the simulations with results from experimental and numerical studies of microchannel and nanochannel flows driven by both standing and traveling SAWs in the literature, we highlight salient features of the flow field that arise and discuss the underlying mechanisms responsible for the flow. In microchannels, boundary layer streaming is the dominant mechanism when the channel height is below the sound wavelength in the liquid, whereas Eckart streaming—arising as a consequence of the attenuation of the sound wave in the liquid—dominates in the form of periodic vortices for larger channel heights. The absence of Eckart streaming and the overlapping of boundary layers in nanochannels with heights below the boundary layer thickness, on the other hand, give rise to a time-averaged dynamic acoustic pressure that results in an inertial-dominant flow, which paradoxically possesses a parabolic-like velocity profile resembling pressure-driven laminar flow. In contrast, if the nanochannel were to be filled instead with air, the significantly lower fluid density leads to a considerable reduction in the dynamic acoustic pressure and hence inertial forcing such that boundary layer streaming once again dominates, asymptotically imposing a slip condition along the channel surface that results in a negative pluglike velocity profile.

A CANDELS-3d-HST Synergy: Resolved Star Formation Patterns at 0.7 less than z less than 1.5

NASA Technical Reports Server (NTRS)

Wuyts, Stijn; Foerster Schreiber, Natascha M.; Nelson, Erica J.; Van Dokkum, Pieter G.; Brammer, Gabe; Chang, Yu-Yen; Faber, Sandra M.; Ferguson, Henry C.; Franx, Marijn; Fumagalli, Mattia;

Ultrastructural analysis of bone nodules formed in vitro by isolated fetal rat calvaria cells

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

Bhargava, U.; Bar-Lev, M.; Bellows, C.G.

When cells enzymatically digested from 21 d fetal rat calvaria are grown in ascorbic acid and Na beta-glycerophosphate, they form discrete three-dimensional nodular structures with the histological and immunohistochemical appearance of woven bone. The present investigation was undertaken to verify that bone-like features were identifiable at the ultrastructural level. The nodules formed on top of a fibroblast-like multilayer of cells. The upper surface of the nodules was lined by a continuous layer of cuboidal osteoblastic cells often seen to be joined by adherens junctions. Numerous microvilli, membrane protrusions, and coated pits could be seen on the upper surface of thesemore » cells, their cytoplasm contained prominent RER and Golgi membranes, and processes extended from their lower surfaces into a dense, highly organized collagenous matrix. Some osteocyte-like cells were completely embedded within this matrix; they also displayed RER and prominent processes which extended through the matrix and often made both adherens and gap junctional contacts with the processes of other cells. The fibroblastic cells not participating in nodule formation were surrounded by a less dense collagenous matrix and, in contrast to the matrix of the nodules, it did not mineralize. An unmineralized osteoid-like layer was seen directly below the cuboidal top layer of cells. A mineralization front was detectable below this in which small, discrete structures resembling matrix vesicles and feathery mineral crystals were evident and frequently associated with the collagen fibrils. More heavily mineralized areas were seen further into the nodule. Electron microprobe and electron and X-ray diffraction analysis confirmed the mineral to be hydroxyapatite.« less

Superhydrophobic Ceramic Coatings by Solution Precursor Plasma Spray

PubMed Central

Cai, Yuxuan; Coyle, Thomas W.; Azimi, Gisele; Mostaghimi, Javad

2016-01-01

This work presents a novel coating technique to manufacture ceramic superhydrophobic coatings rapidly and economically. A rare earth oxide (REO) was selected as the coating material due to its hydrophobic nature, chemical inertness, high temperature stability, and good mechanical properties, and deposited on stainless steel substrates by solution precursor plasma spray (SPPS). The effects of various spraying conditions including standoff distance, torch power, number of torch passes, types of solvent and plasma velocity were investigated. The as-sprayed coating demonstrated a hierarchically structured surface topography, which closely resembles superhydrophobic surfaces found in nature. The water contact angle on the SPPS superhydrophobic coating was up to 65% higher than on smooth REO surfaces. PMID:27091306

Renal cell carcinoma with rhabdoid-like features lack intracytoplasmic inclusion bodies and show aggressive behavior.

PubMed

Sugimoto, Masaaki; Kohashi, Kenichi; Kuroiwa, Kentaro; Abe, Tatsuro; Yamada, Yuichi; Shiota, Masaki; Imada, Kenjiro; Naito, Seiji; Oda, Yoshinao

2016-03-01

In renal cell carcinoma (RCC), tumor cells with rhabdoid features are characterized by eccentric nuclei, prominent nucleoli, and eosinophilic cytoplasm with intracytoplasmic inclusion bodies. In RCC, tumor cells have also been observed resembling rhabdomyoblasts or rhabdoid but without intracytoplasmic inclusion bodies, and here, we defined these rhabdoid-like features of these cells. To this end, we studied a series of clear cell RCC (ccRCC) with rhabdoid features and compared them with a series of ccRCC with rhabdoid-like features to clarify the differences in the immunohistochemical profile and biological behavior. From 695 cases of ccRCC (80.8 % of all RCCs), 18 cases with rhabdoid features (2.1 % of all RCCs) and 25 cases with rhabdoid-like features (2.9 % of all RCCs) were investigated. The 5-year survival rate for ccRCC with rhabdoid features was 44.7 % and for ccRCC with rhabdoid-like features 30.3 %. Although ccRCC with rhabdoid features showed immunohistochemical co-expression of epithelial markers and vimentin as seen in malignant rhabdoid tumors, ccRCC with rhabdoid-like features showed no such co-expression. Multivariate analyses of cancer-specific survival revealed that perinephric tissues invasion was an independent prognostic factor in ccRCC with rhabdoid features (p = 0.0253) but not in ccRCC with rhabdoid-like features. In summary, although their prognosis is similar, the marker profile and pattern of extension of ccRCC with rhabdoid-like is different from that of ccRCC with rhabdoid features. Therefore, ccRCC with rhabdoid-like features should be distinguished from ccRCC with rhabdoid features.

Nanosilver particle formation on a high surface area titanate.

PubMed

Shi, Meng; Lin, Christopher C H; Wu, Lan; Holt, Christopher M B; Mitlin, David; Kuznicki, Steven M

2010-12-01

Titanium based molecular sieves, such as ETS-10, have the ability to exchange silver ions and subsequently support self assembly of stable silver nanoparticles when heated. We report that a high surface area sodium titanate (resembling ETS-2) displays a similar ability to self template silver nanoparticles on its surface. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) show high concentrations of silver nanoparticles on the surface of this sodium titanate, formed by thermal reduction of exchanged silver cations. The nanoparticles range in size from 4 to 12 nm, centered at around 6 nm. In addition to SEM and TEM, XRD and surface area analysis were used to characterize the material. The results indicate that this sodium titanate has a high surface area (>263 m2/g), and high ion exchange capacity for silver (30+ wt%) making it an excellent substrate for the exchange and generation of uniform, high-density silver nanoparticles.

Formation of Germa-ketenimine on the Ge(100) Surface by Adsorption of tert-Butyl Isocyanide.

PubMed

Shong, Bonggeun; Yoo, Jong Suk; Sandoval, Tania E; Bent, Stacey F

2017-06-28

Reactions of the (100) surfaces of Ge and Si with organic molecules have been generally understood within the concept of "dimers" formed by the 2 × 1 surface reconstruction. In this work, the adsorption of tert-butyl isocyanide on the Ge(100)-2 × 1 surface at large exposures is investigated under ultrahigh vacuum conditions. A combination of infrared spectroscopy, X-ray photoelectron spectroscopy, and temperature-programmed desorption experiments along with dispersion-corrected density functional theory calculations is used to determine the surface products. Upon adsorption of a dense monolayer of tert-butyl isocyanide, a product whose structure resembles a germa-ketenimine (N=C=Ge) with σ donation toward and π back-donation from the Ge(100) surface appears. Formation of this structure involves divalent-type surface Ge atoms that arise from cleavage of the Ge(100)-2 × 1 surface dimers. Our results reveal an unprecedented class of reactions of organic molecules at the Ge(100) surface.

Dry Climate as Major Factor Controlling Formation of Hydrated Sulfate Minerals in Valles Marineris on Mars

NASA Astrophysics Data System (ADS)

Szynkiewicz, A.

2016-12-01

In this study, a model for the formation of hydrated sulfate salts (Mg-Ca-Na sulfates) in the Rio Puerco watershed of New Mexico, a terrestrial analog site from the semi-arid Southwest U.S., was used to assess the origin and climate condition that may have controlled deposition of hydrated sulfates in Valles Marineris on Mars. In this analog site, the surface accumulation of sulfate minerals along canyon walls, slopes and valley surfaces closely resemble occurrences of hydrated sulfates in Valles Marineris on Mars. Significant surface accumulations of Mg-Ca-Na sulfates are a result of prevailing semiarid conditions and a short-lived hydrological cycle that mobilizes sulfur present in the bedrock as sulfides, sulfate minerals, and atmospheric deposition. Repeating cycles of salt dissolution and re-precipitation appear to be the underpinning processes that serve to transport sulfate from bedrock to sulfate salts (e.g., efflorescences) and into surface water. This process occurs in the shallow surface environment and is not accompanied by deep groundwater flow because of prevailing dry conditions and low annual precipitation. Generally, close resemblance of surface occurrence and mineralogical composition of sulfate salts between the studied terrestrial analog and Valles Marineris suggest that a similar sulfate cycle, involving limited water activity during formation of hydrated sulfates, was once present in Valles Marineris. Measured as efflorescence, the distributed surface mass of hydrated sulfates in Valles Marineris is relatively small (4 to 42%) when compared to terrestrial settings with higher surface accumulation of sulfate minerals such as the White Sands gypsum dune field. Under semi-arid conditions similar to the studied analog in the Rio Pueurco watershed, it would take only 100 to 1,000 years to activate an equivalent flux of aqueous sulfate in Valles Marineris, when comparing terrestrial annual sulfate fluxes from the Rio Puerco watershed with the amount of hydrated sulfates and the size of Valles Marineris. The results of this study suggest that during formation of hydrated sulfates in Valles Marineris on Mars the climate was relatively dry with limited aqueous processes in surface environment.

The spread of attention across features of a surface

PubMed Central

Ernst, Zachary Raymond; Jazayeri, Mehrdad

2013-01-01

Contrasting theories of visual attention have emphasized selection by spatial location, individual features, and whole objects. We used functional magnetic resonance imaging to ask whether and how attention to one feature of an object spreads to other features of the same object. Subjects viewed two spatially superimposed surfaces of random dots that were segregated by distinct color-motion conjunctions. The color and direction of motion of each surface changed smoothly and in a cyclical fashion. Subjects were required to track one feature (e.g., color) of one of the two surfaces and detect brief moments when the attended feature diverged from its smooth trajectory. To tease apart the effect of attention to individual features on the hemodynamic response, we used a frequency-tagging scheme. In this scheme, the stimulus features (color and direction of motion) are modulated periodically at distinct frequencies so that the contribution of each feature to the hemodynamics can be inferred from the harmonic response at the corresponding frequency. We found that attention to one feature (e.g., color) of one surface increased the response modulation not only to the attended feature but also to the other feature (e.g., motion) of the same surface. This attentional modulation was evident in multiple visual areas and was present as early as V1. The spread of attention to the behaviorally irrelevant features of a surface suggests that attention may automatically select all features of a single object. Thus object-based attention may be supported by an enhancement of feature-specific sensory signals in the visual cortex. PMID:23883860

Towards predictive models for transitionally rough surfaces

NASA Astrophysics Data System (ADS)

Abderrahaman-Elena, Nabil; Garcia-Mayoral, Ricardo

2017-11-01

We analyze and model the previously presented decomposition for flow variables in DNS of turbulence over transitionally rough surfaces. The flow is decomposed into two contributions: one produced by the overlying turbulence, which has no footprint of the surface texture, and one induced by the roughness, which is essentially the time-averaged flow around the surface obstacles, but modulated in amplitude by the first component. The roughness-induced component closely resembles the laminar steady flow around the roughness elements at the same non-dimensional roughness size. For small - yet transitionally rough - textures, the roughness-free component is essentially the same as over a smooth wall. Based on these findings, we propose predictive models for the onset of the transitionally rough regime. Project supported by the Engineering and Physical Sciences Research Council (EPSRC).

M553 sphere forming experiment: Pure nickel specimen evaluation

NASA Technical Reports Server (NTRS)

Johnson, P. C.; Peters, E. T.

1973-01-01

A region or cap of very fine two-dimensional surface growth structure was observed at the top of three of the six pure nickel flight specimens. Such two-dimensional surface growth structures have been observed both on the ground-based specimens and on other surface areas of the flight specimens. However, the fine structures observed on the three flight samples are at least an order of magnitude finer than those previously observed, and resemble similar localized, fine, two-dimensional surface structures observed in both ground and flight specimens for the nickel alloys. The two-dimensional growth areas consist primarily of fine equiaxed grains, specimen SL-2.6, fine dendrites, specimen SL-2.5, or a core of fine equiaxed grains surrounded by a ring of fine dendrites, specimen SL-1.9.

Chemical Analysis of the Moon at the Surveyor VI Landing Site: Preliminary Results.

PubMed

Turkevich, A L; Patterson, J H; Franzgrote, E J

1968-06-07

The alpha-scattering experiment aboard soft-landing Surveyor VI has provided a chemical analysis of the surface of the moon in Sinus Medii. The preliminary results indicate that, within experimental errors, the composition is the same as that found by Surveyor V in Mare Tranquillitatis. This finding suggests that large portions of the lunar maria resemble basalt in composition.

Surface Interaction of Bent-Core Liquid Crystals "Slipping on a Banana Peel"

NASA Astrophysics Data System (ADS)

Iglesias Gonzalez, Wilder G.

The main emphasis and focus of this talk revolves around liquid crystalline molecules with frustrated symmetry, molecules with a kink in the core resembling the shape of a banana. These novel materials are not only suitable and interesting for the common liquid crystal display field as fast switching candidates, but for a whole wide range of potential applications, such as: power generation, microscale actuators, optical storage devices, to name a few. Understanding surface interactions of these mesogens is a key factor in controlling and unveiling the vast potential capabilities of such liquid crystals.

A new glossiphoniid leech from Catemaco Lake, Veracruz, México.

PubMed

Oceguera-Figueroa, Alejandro

2008-04-01

Haementeria acuecueyetzin n. sp. from Catemaco Lake, Veracruz, Mexico, is described based on the examination of 6 specimens. This new hematophagous leech species resembles other members of the genus in the number and position of the eyespots, number of compact salivary glands, and in the presence of 2 pairs of spheroidal mycetomes, but it is distinguished from the other species by having 6 rows of longitudinal smooth white papillae in the dorsal surface and numerous tubercles in dorsal and ventral surfaces. This new species represents the third species of Haementeria in the Northern Hemisphere of the Americas.

Template optimization and transfer in perceptual learning.

PubMed

Kurki, Ilmari; Hyvärinen, Aapo; Saarinen, Jussi

2016-08-01

We studied how learning changes the processing of a low-level Gabor stimulus, using a classification-image method (psychophysical reverse correlation) and a task where observers discriminated between slight differences in the phase (relative alignment) of a target Gabor in visual noise. The method estimates the internal "template" that describes how the visual system weights the input information for decisions. One popular idea has been that learning makes the template more like an ideal Bayesian weighting; however, the evidence has been indirect. We used a new regression technique to directly estimate the template weight change and to test whether the direction of reweighting is significantly different from an optimal learning strategy. The subjects trained the task for six daily sessions, and we tested the transfer of training to a target in an orthogonal orientation. Strong learning and partial transfer were observed. We tested whether task precision (difficulty) had an effect on template change and transfer: Observers trained in either a high-precision (small, 60° phase difference) or a low-precision task (180°). Task precision did not have an effect on the amount of template change or transfer, suggesting that task precision per se does not determine whether learning generalizes. Classification images show that training made observers use more task-relevant features and unlearn some irrelevant features. The transfer templates resembled partially optimized versions of templates in training sessions. The template change direction resembles ideal learning significantly but not completely. The amount of template change was highly correlated with the amount of learning.

A systematic approach to identify therapeutic effects of natural products based on human metabolite information.

PubMed

Noh, Kyungrin; Yoo, Sunyong; Lee, Doheon

2018-06-13

Natural products have been widely investigated in the drug development field. Their traditional use cases as medicinal agents and their resemblance of our endogenous compounds show the possibility of new drug development. Many researchers have focused on identifying therapeutic effects of natural products, yet the resemblance of natural products and human metabolites has been rarely touched. We propose a novel method which predicts therapeutic effects of natural products based on their similarity with human metabolites. In this study, we compare the structure, target and phenotype similarities between natural products and human metabolites to capture molecular and phenotypic properties of both compounds. With the generated similarity features, we train support vector machine model to identify similar natural product and human metabolite pairs. The known functions of human metabolites are then mapped to the paired natural products to predict their therapeutic effects. With our selected three feature sets, structure, target and phenotype similarities, our trained model successfully paired similar natural products and human metabolites. When applied to the natural product derived drugs, we could successfully identify their indications with high specificity and sensitivity. We further validated the found therapeutic effects of natural products with the literature evidence. These results suggest that our model can match natural products to similar human metabolites and provide possible therapeutic effects of natural products. By utilizing the similar human metabolite information, we expect to find new indications of natural products which could not be covered by previous in silico methods.

Morphological and cellular characterization of the fetal canine (Canis lupus familiaris) subventricular zone, rostral migratory stream and olfactory bulb.

PubMed

Orechio, Dailiany; Aguiar, Bruna Andrade; Diniz, Giovanne Baroni; Bittencourt, Jackson Cioni; Haemmerle, Carlos A; Watanabe, Ii-Sei; Miglino, Maria Angelica; Castelucci, Patricia

2018-05-12

The existence of neurogenesis in the adult brain is a widely recognized phenomenon, occurring in the subventricular zone (SVZ) of the lateral ventricles and the subgranular zone of the dentate gyrus in several vertebrate species. Neural precursors originated in the SVZ migrate to the main olfactory bulb (MOB), originating the rostral migratory stream (RMS) in the process. To better understand the formation of the adult neurogenic niches in dogs, we investigated the cellular composition and morphological organization of these areas in 57 days-old dog fetuses. Using multiple immunohistochemical markers, we demonstrated that the SVZ in the canine fetus is remarkably similar to the adult SVZ, with glial GFAP-immunoreactive (-ir) cells, DCX-ir neuroblasts and SOX2-ir neuronal progenitors tangentially organized along the dorsal lateral ventricle. The fetal RMS has all the features of its adult counterpart and closely resembles the RMS of other mammalian species. The late-development canine MOB has most of the neurochemical features of the adult MOB, including an early-developed TH-ir population and maturing CALR-ir interneurons, but CALB-ir neurons in the granule cell layer will only appear in the post-partum period. Taken together, our results suggest that the canine fetal development of adult neurogenic niches closely resembles those of primates, and dogs may be suitable models of human adult neurogenesis. This article is protected by copyright. All rights reserved. © 2018 Wiley Periodicals, Inc.

Nakhla: a Martian Meteorite with Indigenous Organic Carbonaceous Features

NASA Technical Reports Server (NTRS)

McKay, D. S.; Gibson, E. K.; Thomas-Keprta, K. L.; Clemett, S. J.; Le, L.; Rahman, Z.; Wentworth, S. J.

2011-01-01

The Nakhla meteorite possesses discrete, well defined, structurally coherent morphologies of carbonaceous phases present within iddingsite alteration zones. Based upon both isotopic measurements and analysis of organic phases the presence of pre-terrestrial organics is now recognized. Within the microcrystalline layers of Nakhla s iddingsite, discrete clusters of salt crystals are present. These salts are predominantly halite (NaCl) with minor MgCl2 crystals. Some CaSO4, likely gypsum, appears to be partially intergrown with some of the halite. EDX mapping shows discrete C-rich features are interspersed among these crystals. A hollow semi-spherical bowl structure ( 3 m ) has been identified and analyzed after using a focused ion beam (FIB) to cut a transverse TEM thin section of the feature and the underlying iddingsite. TEM/EDX analysis reveals that the feature is primarily carbonaceous containing C with lesser amounts of Si, S, Ca, Cl, F, Na, and minor Mn and Fe; additionally a small peak consistent with N, which has been previously seen in Nakhla carbonaceous matter, is also present. Selected area electron diffraction (SAED) shows that this C-rich material is amorphous (lacking any long-range crystallographic order) and is not graphite or carbonate. Micro-Raman spectra acquired from the same surface from which the FIB section was extracted demonstrate a typical kerogen-like D and G band structure with a weak absorption peak at 1350 and a stronger peak at 1600/cm. The C-rich feature is intimately associated with both the surrounding halite and underlying iddingsite matrix. Both iddingsite and salts are interpreted as having formed as evaporate assemblages from progressive evaporation of water bodies on Mars. This assemblage, sans the carbonaceous moieties, closely resembles iddingsite alteration features previously described which were interpreted as indigenous Martian assemblages. These distinctive macromolecular carbonaceous structures in Nakhla may represent one of the sources of the high molecular weight organic material previously identified in Nakhla. While we do not speculate on the origin of these unique carbonaceous structures, we note that the significance of such observations is that it may allow us to construct a C-cycle for Mars based on the C chemistry of the Martian meteorites with obvious implications for astrobiology and the prebiotic evolution of Mars. In any case, our observations strongly suggest that organic C exists as micrometersize, discrete structures on Mars.

Geological Map of the Fredegonade (V-57) Quadrangle, Venus: Status Report

NASA Technical Reports Server (NTRS)

Ivanov, M. A.; Head, J. W.

2010-01-01

The Fredegonde quadrangle (V-57; 50-75degS, 60-120degE, Fig. 1) corresponds to the northeastern edge of Lada Terra and covers a broad area of the topographic province of midlands (0-2 km above MPR [1,2]). This province is most abundant on Venus and displays a wide variety of units and structures [3-11]. The sequence of events that formed the characteristic features of the midlands is crucially important in understanding of the timing and modes of evolution of this topographic province. Topographically, the Fredegonde quadrangle is within a transition zone between the elevated portion of Lada Terra to the west (Quetzalpetlatl-Boala Coronae rise, approx.3.5 km) and the lowland of Aino Planitia to the north and northeast (approx.-0.5 km). This transition is one of the key features of the V-57 quadrangle. In this respect the quadrangle resembles the region of V-4 quadrangle [12] that shows transition between the midlands and the lowlands of Atalanta Planitia. One of the main goals of our mapping within the V-57 quadrangle is comparison of this region with the other transitional topographic zones such as quadrangles V-4 and V-3 [13]. The most prominent features in the V-57 quadrangle are linear deformational zones of grooves and large coronae. The zones characterize the central and NW portions of the map area and represent broad (up to 100s of km wide) ridges that are 100s of m high. Morphologically and topographically, these zones are almost identical to the groove belt/corona complexes at the western edge of Atalanta Planitia [12]. Within the Fredegonde area, however, the zones are oriented at high angles to the general trend of elongated Aino Planitia, whereas within the V-4 quadrangle they are parallel to the edge of Atalanta Planitia. Relatively small (100s of km across, 100s of m deep) equidimensional basins occur between the corona-groove-chains in the area of V-57 quadrangle. These basins are similar to those that populate the area of the V-3 quadrangle [13]. Broad regional plains cover the surface of the basins in both regions. In contrast to Fredegonde, the area of the V-3 quadrangle displays a greater diversity of units and features [13]. Here we describe units that make up the surface within the V-57 quadrangle and present a summary of our geological map that shows the areal distribution of the major groups of units.

Mud Volcanoes - Analogs to Martian Cones and Domes (by the Thousands!)

NASA Technical Reports Server (NTRS)

Allen, Carlton C.; Oehler, Dorothy

2010-01-01

Mud volcanoes are mounds formed by low temperature slurries of gas, liquid, sediments and rock that erupt to the surface from depths of meters to kilometers. They are common on Earth, with estimates of thousands onshore and tens of thousands offshore. Mud volcanoes occur in basins with rapidly-deposited accumulations of fine-grained sediments. Such settings are ideal for concentration and preservation of organic materials, and mud volcanoes typically occur in sedimentary basins that are rich in organic biosignatures. Domes and cones, cited as possible mud volcanoes by previous authors, are common on the northern plains of Mars. Our analysis of selected regions in southern Acidalia Planitia has revealed over 18,000 such features, and we estimate that more than 40,000 occur across the area. These domes and cones strongly resemble terrestrial mud volcanoes in size, shape, morphology, associated flow structures and geologic setting. Geologic and mineralogic arguments rule out alternative formation mechanisms involving lava, ice and impacts. We are studying terrestrial mud volcanoes from onshore and submarine locations. The largest concentration of onshore features is in Azerbaijan, near the western edge of the Caspian Sea. These features are typically hundreds of meters to several kilometers in diameter, and tens to hundreds of meters in height. Satellite images show spatial densities of 20 to 40 eruptive centers per 1000 square km. Many of the features remain active, and fresh mud flows as long as several kilometers are common. A large field of submarine mud volcanoes is located in the Gulf of Cadiz, off the Atlantic coasts of Morocco and Spain. High-resolution sonar bathymetry reveals numerous km-scale mud volcanoes, hundreds of meters in height. Seismic profiles demonstrate that the mud erupts from depths of several hundred meters. These submarine mud volcanoes are the closest morphologic analogs yet found to the features in Acidalia Planitia. We are also conducting laboratory analyses of surface samples collected from mud volcanoes in Azerbaijan, Taiwan and Japan. X-ray diffraction, visible / near infrared reflectance spectroscopy and Raman spectroscopy show that the samples are dominated by mixed-layer smectite clays, along with quartz, calcite and pyrite. Thin section analysis by optical and scanning electron microscopy confirms the mineral identifications. These samples also contain chemical and morphological biosignatures, including common microfossils, with evidence of partial replacement by pyrite. The bulk samples contain approximately 1 wt% total organic carbon and 0.4 mg / gm volatile hydrocarbons. The thousands of features in Acidalia Planitia cited as analogous to terrestrial mud volcanoes clearly represent an important element in the sedimentary record of Mars. Their location, in the distal depocenter for massive Hesperian-age floods, suggests that they contain fine-grained sediments from a large catchment area in the martian highlands. We have proposed these features as a new class of exploration target that can provide access to minimally-altered material from significant depth. By analogy to terrestrial mud volcanoes, these features may also be excellent sites for the sampling martian organics and subsurface microbial life, if such exist or ever existed.

A neural network technique for remeshing of bone microstructure.

PubMed

Fischer, Anath; Holdstein, Yaron

2012-01-01

Today, there is major interest within the biomedical community in developing accurate noninvasive means for the evaluation of bone microstructure and bone quality. Recent improvements in 3D imaging technology, among them development of micro-CT and micro-MRI scanners, allow in-vivo 3D high-resolution scanning and reconstruction of large specimens or even whole bone models. Thus, the tendency today is to evaluate bone features using 3D assessment techniques rather than traditional 2D methods. For this purpose, high-quality meshing methods are required. However, the 3D meshes produced from current commercial systems usually are of low quality with respect to analysis and rapid prototyping. 3D model reconstruction of bone is difficult due to the complexity of bone microstructure. The small bone features lead to a great deal of neighborhood ambiguity near each vertex. The relatively new neural network method for mesh reconstruction has the potential to create or remesh 3D models accurately and quickly. A neural network (NN), which resembles an artificial intelligence (AI) algorithm, is a set of interconnected neurons, where each neuron is capable of making an autonomous arithmetic calculation. Moreover, each neuron is affected by its surrounding neurons through the structure of the network. This paper proposes an extension of the growing neural gas (GNN) neural network technique for remeshing a triangular manifold mesh that represents bone microstructure. This method has the advantage of reconstructing the surface of a genus-n freeform object without a priori knowledge regarding the original object, its topology, or its shape.

A new species of Monstrilla Dana, 1849 (Copepoda: Monstrilloida: Monstrillidae) from Korea, including a key to species from the north-west Pacific.

PubMed

Lee, Jimin; Chang, Cheon Young

2016-10-11

A new species of monstrilloid copepod belonging to the genus Monstrilla Dana, 1849 is recorded from South Korea. Specimens were obtained between May of 2012 and January of 2014 from inshore waters along the coasts of the East Sea, South Sea, and Jeju Island, using a light trap installed at quays and wharves overnight. Monstrilla ilhoii sp. nov. is characterized by a remarkable combination of a large body size (females about 3.8 mm long, males about 2.8 mm long), a polygonal ridge pattern (cuticular reticulation) over the entire body surface, and an antennule armature featuring a supernumerary spiniform seta (4d₃) in females and a dagger-shaped distal spine (6₂) in both sexes. In other respects M. ilhoii sp. nov. most closely resembles M. lata Desai & Bal, 1963; both species have one and three setae on the endopodal and exopodal lobes, respectively, of female leg 5, a horseshoe-shaped male genital apparatus with marked undulations along the whole distal margin, and six setae on each caudal ramus in both sexes. This paper provides a description of the new species, taxonomic remarks on its morphological features, and differential diagnoses with respect to its allies. Scanning electron microscopy was used to document significant morphological microcharacters. The species of Monstrilla known from five sub-regions of the north-west Pacific are enumerated with the source references, and keys to the females and males of these species are provided.

Building the Peanut: Simulations and Observations of Peanut-shaped Structures and Ansae in Face-on Disk Galaxies

NASA Astrophysics Data System (ADS)

Saha, Kanak; Graham, Alister W.; Rodríguez-Herranz, Isabel

2018-01-01

Peanut/x-shaped features observed in a significant fraction of disk galaxies are thought to have formed from vertically buckled bars. Despite being three-dimensional structures, they are preferentially detected in near edge-on projection. Only a few galaxies are found to have displayed such structures when their disks are relatively face-on—suggesting that either they are generally weak in face-on projection or many may be hidden by the light of their galaxy’s face-on disk. Here, we report on three (collisionless) simulated galaxies displaying peanut-shaped structures when their disks are seen both face-on and edge-on—resembling a three-dimensional peanut or dumbbell. Furthermore, these structures are accompanied by ansae and an outer ring at the end of the bar—as seen in real galaxies such as IC 5240. The same set of quantitative parameters used to measure peanut structures in real galaxies has been determined for the simulated galaxies, and a broad agreement is found. In addition, the peanut length grows in tandem with the bar, and is a maximum at half the length of the bar. Beyond the cutoff of these peanut structures, toward the end of the bar, we discover a new positive/negative feature in the B 6 radial profile associated with the isophotes of the ansae/ring. Our simulated, self-gravitating, three-dimensional peanut structures display cylindrical rotation even in the near-face-on disk projection. In addition, we report on a kinematic pinch in the velocity map along the bar minor axis, matching that seen in the surface density map.

A mixed odontogenic sarcoma: A challenging histopathologic case and brief review of the literature

PubMed Central

Atarbashi-Moghadam, Saede; Lotfi, Ali; Mokhtari, Sepideh

2018-01-01

Ameloblastic fibro-odontosarcoma (AFOS) is an extremely rare malignant mixed odontogenic tumor. The ectomesenchymal part of the neoplasm shows malignancy, whereas the epithelial component is rather benign. In addition, small areas with deposition of enamel matrix and dentine material are seen. The rarity of this neoplasm and microscopic similarities with other malignant and benign tumors can lead to diagnostic problems. Here, we describe the histopathologic features of a new case of AFOS of the mandible in a 34-year-old female patient. It is essential for oral pathologists to be familiar with the microscopic features of this rare neoplasm to have a proper diagnosis. This is also the first reported case of AFOS that closely resembles osteosarcoma in some areas. PMID:29491601

Gullies and Bedrock in Nirgal Vallis

NASA Image and Video Library

2015-02-11

The gullies in this image are within the valley wall of an ancient channel-Nirgal Vallis-a testament to flowing water in Mars' ancient past. However, the formation of gullies are still the subject of much debate with respect to their formation: "wet" vs. "dry" or even "dry" with the aid of some lubricating fluid. Gullies most commonly form in the steep walls of simple craters. Gullies are common even in cold arctic deserts on Earth (e.g., the Haughton impact structure on Devon Island). This suggests that these provocative features can form on a mostly dry Mars that is only sporadically wet. Regardless, these features bear a remarkable resemblance to flowers, including the blossom, petals, stem, and roots. Can you see it too? http://photojournal.jpl.nasa.gov/catalog/PIA19294

Pituitary and ovarian abnormalities demonstrated by CT and ultrasound in children with features of the McCune-Albright syndrome

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

Rieth, K.G.; Comite, F.; Shawker, T.H.

1984-11-01

In a random series of 97 children referred to the National Institutes of Health with a presumptive diagnosis of precocious puberty, eight girls were found to have features of the McCune-Albright syndrome, including fibrous dysplasia of bone and/or skin lesions resembling cafe au lait spots. Radiographic evaluation of these patients included computed tomography of the head and pelvic ultrasound. The pituitary glands were suspicious for abnormality in five of the eight girls. Seven girls underwent pelvic ultrasound, and in all of them the ovaries were considered to be abnormal for their chronological age; in addition, two had functional ovarian cysts.more » The role of diagnostic radiological studies in the diagnosis of this syndrome is discussed.« less

Cyto-histological correlation of Xp11.2 translocation/TFE3 gene fusion associated renal cell carcinoma: Report of a case with review of literature.

PubMed

Manucha, Varsha; Sessums, Mary T; Lewin, Jack; Akhtar, Israh

2018-03-01

The MiT family translocation renal cell carcinomas (RCCs) are relatively rare in comparison to the conventional RCC. The cytologic features overlap with conventional clear cell RCC and papillary RCCs, thereby making the diagnosis extremely challenging. Here, we describe a case of TFE3 translocation associated RCC in a 58-year-old patient, with emphasis on cytomorphologic features and clues toward this diagnostic entity. Correlating the cytohistologic findings and review of touch imprints revealed that presence of hyaline nodules resembling leisegang rings and psammoma bodies in cytologic smears from kidney tumors serve as an important clue in raising a suspicion for the diagnosis of MiT family translocation RCCs. © 2017 Wiley Periodicals, Inc.

DARC: Mapping Surface Topography by Ray-Casting for Effective Virtual Screening at Protein Interaction Sites.

PubMed

Gowthaman, Ragul; Miller, Sven A; Rogers, Steven; Khowsathit, Jittasak; Lan, Lan; Bai, Nan; Johnson, David K; Liu, Chunjing; Xu, Liang; Anbanandam, Asokan; Aubé, Jeffrey; Roy, Anuradha; Karanicolas, John

2016-05-12

Protein-protein interactions represent an exciting and challenging target class for therapeutic intervention using small molecules. Protein interaction sites are often devoid of the deep surface pockets presented by "traditional" drug targets, and crystal structures reveal that inhibitors typically engage these sites using very shallow binding modes. As a consequence, modern virtual screening tools developed to identify inhibitors of traditional drug targets do not perform as well when they are instead deployed at protein interaction sites. To address the need for novel inhibitors of important protein interactions, here we introduce an alternate docking strategy specifically designed for this regime. Our method, termed DARC (Docking Approach using Ray-Casting), matches the topography of a surface pocket "observed" from within the protein to the topography "observed" when viewing a potential ligand from the same vantage point. We applied DARC to carry out a virtual screen against the protein interaction site of human antiapoptotic protein Mcl-1 and found that four of the top-scoring 21 compounds showed clear inhibition in a biochemical assay. The Ki values for these compounds ranged from 1.2 to 21 μM, and each had ligand efficiency comparable to promising small-molecule inhibitors of other protein-protein interactions. These hit compounds do not resemble the natural (protein) binding partner of Mcl-1, nor do they resemble any known inhibitors of Mcl-1. Our results thus demonstrate the utility of DARC for identifying novel inhibitors of protein-protein interactions.

Decoding the spectroscopic features and time scales of aqueous proton defects

NASA Astrophysics Data System (ADS)

Napoli, Joseph A.; Marsalek, Ondrej; Markland, Thomas E.

2018-06-01

Acid solutions exhibit a variety of complex structural and dynamical features arising from the presence of multiple interacting reactive proton defects and counterions. However, disentangling the transient structural motifs of proton defects in the water hydrogen bond network and the mechanisms for their interconversion remains a formidable challenge. Here, we use simulations treating the quantum nature of both the electrons and nuclei to show how the experimentally observed spectroscopic features and relaxation time scales can be elucidated using a physically transparent coordinate that encodes the overall asymmetry of the solvation environment of the proton defect. We demonstrate that this coordinate can be used both to discriminate the extremities of the features observed in the linear vibrational spectrum and to explain the molecular motions that give rise to the interconversion time scales observed in recent nonlinear experiments. This analysis provides a unified condensed-phase picture of the proton structure and dynamics that, at its extrema, encompasses proton sharing and spectroscopic features resembling the limiting Eigen [H3O(H2O)3]+ and Zundel [H(H2O)2]+ gas-phase structures, while also describing the rich variety of interconverting environments in the liquid phase.

Nd isotopic composition and REE pattern in the surface waters of the eastern Indian Ocean and its adjacent seas

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

Amakawa, Hiroshi; Alibo, D.S.; Nozaki, Yoshiyuki

2000-05-01

The Nd isotopic composition and dissolved rare earth elements (REEs) have been measured in the surface waters along the 1996/97 R.V. Hakuho-Maru Expedition route from Tokyo to the Southern Ocean, southwest of Australia, through the Philippine and Indonesian Archipelago, the eastern Indian Ocean, the Bay of Bengal and the South China Sea. The radiogenic {epsilon}{sub Nd} values of {minus}1.3 and {minus}1.4 were found in the Sulu Sea and near the Lombok Strait, indicating the strong influence of surrounding volcanic islands, whereas non-radiogenic {epsilon}{sub Nd} values of less than {minus}10 were found in the Southern Ocean and the Bay of Bengalmore » suggesting Nd of continental origin. The dissolved Nd concentrations also showed a wide range of variation from 2.8 to 19.6 pmol/kg and the trivalent REE patterns exhibited characteristic features that can be grouped into each different oceanic province. The geographical distribution of dissolved Nd is different from that of atmospherically derived {sup 210}Pb, but generally resembles that of coastally derived {sup 228}Ra. This strongly suggests that fluvial and coastal input predominates over eolian input for dissolved Nd in the surface ocean. However, the riverine dissolved Nd flux appears to be relatively minor, and remobilization of Nd from coastal and shelf sediments may play an important role in the total Nd input to the ocean. By modeling the distributions of the isotopic composition and concentration of Nd together with the activity ratio of {sup 228}Ra/{sup 226}Ra in the southeastern Indian Ocean, the authors estimate a mean residence time of Nd in the surface mixed layer to be 1.5--2.6 years. The short mean residence time is comparable with, or slightly longer than that of {sup 210}Pb suggesting similar chemical reactivity.« less

Anyone Else Think This Looks Like the Cookie Monster?

NASA Image and Video Library

2017-12-08

NASA image acquired August 29, 2012 Ok, so maybe it's just me. But the superposition of younger craters on older craters (in this case two smaller craters upon the rim of an older crater) can result in landforms that appear to resemble more familiar shapes to human eyes. More generally, the Law of Superposition allows scientists to determine which surface features pre- and postdate others, leading to a better understanding of the geological history of different regions of Mercury's surface. This image was acquired as a high-resolution targeted observation. Targeted observations are images of a small area on Mercury's surface at resolutions much higher than the 200-meter/pixel morphology base map. It is not possible to cover all of Mercury's surface at this high resolution, but typically several areas of high scientific interest are imaged in this mode each week. The MESSENGER spacecraft is the first ever to orbit the planet Mercury, and the spacecraft's seven scientific instruments and radio science investigation are unraveling the history and evolution of the Solar System's innermost planet. Visit the Why Mercury? section of this website to learn more about the key science questions that the MESSENGER mission is addressing. During the one-year primary mission, MESSENGER acquired 88,746 images and extensive other data sets. MESSENGER is now in a yearlong extended mission, during which plans call for the acquisition of more than 80,000 additional images to support MESSENGER's science goals. Go here to read more about the MESSENGER mission: www.nasa.gov/mission_pages/messenger/main/index.html Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Spatiotemporal dynamics of surface water networks across a global biodiversity hotspot—implications for conservation

NASA Astrophysics Data System (ADS)

Tulbure, Mirela G.; Kininmonth, Stuart; Broich, Mark

2014-11-01

The concept of habitat networks represents an important tool for landscape conservation and management at regional scales. Previous studies simulated degradation of temporally fixed networks but few quantified the change in network connectivity from disintegration of key features that undergo naturally occurring spatiotemporal dynamics. This is particularly of concern for aquatic systems, which typically show high natural spatiotemporal variability. Here we focused on the Swan Coastal Plain, a bioregion that encompasses a global biodiversity hotspot in Australia with over 1500 water bodies of high biodiversity. Using graph theory, we conducted a temporal analysis of water body connectivity over 13 years of variable climate. We derived large networks of surface water bodies using Landsat data (1999-2011). We generated an ensemble of 278 potential networks at three dispersal distances approximating the maximum dispersal distance of different water dependent organisms. We assessed network connectivity through several network topology metrics and quantified the resilience of the network topology during wet and dry phases. We identified ‘stepping stone’ water bodies across time and compared our networks with theoretical network models with known properties. Results showed a highly dynamic seasonal pattern of variability in network topology metrics. A decline in connectivity over the 13 years was noted with potential negative consequences for species with limited dispersal capacity. The networks described here resemble theoretical scale-free models, also known as ‘rich get richer’ algorithm. The ‘stepping stone’ water bodies are located in the area around the Peel-Harvey Estuary, a Ramsar listed site, and some are located in a national park. Our results describe a powerful approach that can be implemented when assessing the connectivity for a particular organism with known dispersal distance. The approach of identifying the surface water bodies that act as ‘stepping stone’ over time may help prioritize surface water bodies that are essential for maintaining regional scale connectivity.

Atmospheric Teleconnection over Eurasia Induced by Aerosol Radiative Forcing during Boreal Spring

NASA Technical Reports Server (NTRS)

Kim, Maeng-Ki; Lau, William K. M.; Chin, Mian; Kim, Kyu-Myong; Sud, Y. C.; Walker, Greg K.

2006-01-01

The direct effects of aerosols on global and regional climate during boreal spring are investigated based on numerical simulations with the NASA Global Modeling and Assimilation Office finite-volume general circulation model (fvGCM) with Microphyics of Clouds with the Relaxed Arakawa Schubert Scheme (McRAS), using aerosol forcing functions derived from the Goddard Ozone Chemistry Aerosol Radiation and Transport model (GOCART). The authors find that anomalous atmospheric heat sources induced by absorbing aerosols (dust and black carbon) excite a planetary-scale teleconnection pattern in sea level pressure, temperature, and geopotential height spanning North Africa through Eurasia to the North Pacific. Surface cooling due to direct effects of aerosols is found in the vicinity and downstream of the aerosol source regions, that is, South Asia, East Asia, and northern and western Africa. Significant atmospheric heating is found in regions with large loading of dust (over northern Africa and the Middle East) and black carbon (over Southeast Asia). Paradoxically, the most pronounced feature in aerosol-induced surface temperature is an east west dipole anomaly with strong cooling over the Caspian Sea and warming over central and northeastern Asia, where aerosol concentrations are low. Analyses of circulation anomalies show that the dipole anomaly is a part of an atmospheric teleconnection pattern driven by atmospheric heating anomalies induced by absorbing aerosols in the source regions, but the influence was conveyed globally through barotropic energy dispersion and sustained by feedback processes associated with the regional circulations. The surface temperature signature associated with the aerosol-induced teleconnection bears striking resemblance to the spatial pattern of observed long-term trend in surface temperature over Eurasia. Additionally, the boreal spring wave train pattern is similar to that reported by Fukutomi et al. associated with the boreal summer precipitation seesaw between eastern and western Siberia. The results of this study raise the possibility that global aerosol forcing during boreal spring may play an important role in spawning atmospheric teleconnections that affect regional and global climates.

'1001' Campylobacters: cultural characteristics of intestinal campylobacters from man and animals.

PubMed

Skirrow, M B; Benjamin, J

1980-12-01

The cultural characteristics of 1220 Campylobacter strains from a variety of sources are described. Forty-two were identified as Campylobacter fetus ssp. fetus (Véron & Chatelain, 1973), 1120 as members of the C. jejuni/C. coli group, and 58 did not conform to any known description. Sixteen of the latter strains had the basic characteristics of C. fetus but were atypical in certain other respects. The other 42 strains had the thermophilic characteristics of the jejuni/coli group, but were resistant to nalidixic acid and had other features in common; it is possible that they represent a new species. They were isolated from 19% of locally caught wild seagulls but only occasionally from other animals and man.Growth at 25 degrees C clearly distinguished strains of C. fetus from those of the jejuni/coli and the nalidixic acid-resistant thermophilic (NARTC) groups. Maximum growth temperature was less reliable for this purpose, and 43 degrees C was found to be better than the traditional 42 degrees C. By arranging the results of three tests (tolerance to 2,3,5-triphenyltetrazolium chloride, growth at 30.5 and 45.5 degrees C) serially in the form of a schema comprising nine categories, the jejuni/coli strains fell into two main groups resembling the Institute Pasteur C. jejuni and C. coli type strains, but these groups could not be clearly defined owing to the existence of strains with intermediate characteristics.Most of the strains from cattle resembled C. jejuni, whereas those from pigs resembled C. coli; poultry strains occupied a more intermediate position. Strains from man and other animals were of mixed types, but most human strains resembled C. jejuni rather than C. coli. The type distribution pattern that most nearly matched that of human indigenous strains was given by a half-and-half mixture of strains from cattle and poultry.

'1001' Campylobacters: cultural characteristics of intestinal campylobacters from man and animals

PubMed Central

Skirrow, M. B.; Benjamin, J.

1980-01-01

The cultural characteristics of 1220 Campylobacter strains from a variety of sources are described. Forty-two were identified as Campylobacter fetus ssp. fetus (Véron & Chatelain, 1973), 1120 as members of the C. jejuni/C. coli group, and 58 did not conform to any known description. Sixteen of the latter strains had the basic characteristics of C. fetus but were atypical in certain other respects. The other 42 strains had the thermophilic characteristics of the jejuni/coli group, but were resistant to nalidixic acid and had other features in common; it is possible that they represent a new species. They were isolated from 19% of locally caught wild seagulls but only occasionally from other animals and man. Growth at 25 °C clearly distinguished strains of C. fetus from those of the jejuni/coli and the nalidixic acid-resistant thermophilic (NARTC) groups. Maximum growth temperature was less reliable for this purpose, and 43 °C was found to be better than the traditional 42 °C. By arranging the results of three tests (tolerance to 2,3,5-triphenyltetrazolium chloride, growth at 30·5 and 45·5 °C) serially in the form of a schema comprising nine categories, the jejuni/coli strains fell into two main groups resembling the Institute Pasteur C. jejuni and C. coli type strains, but these groups could not be clearly defined owing to the existence of strains with intermediate characteristics. Most of the strains from cattle resembled C. jejuni, whereas those from pigs resembled C. coli; poultry strains occupied a more intermediate position. Strains from man and other animals were of mixed types, but most human strains resembled C. jejuni rather than C. coli. The type distribution pattern that most nearly matched that of human indigenous strains was given by a half-and-half mixture of strains from cattle and poultry. PMID:7462593

Assessing the intersection/remagnetization puzzle with synthetic apparent polar wander paths

NASA Astrophysics Data System (ADS)

Pivarunas, Anthony F.; Meert, Joseph G.; Miller, Scott R.

2018-05-01

Paleomagnetic data are of variable quality. To assist in a systematic assessment of data, a set of seven quality criteria (VQ1 - VQ7) were introduced by Van der Voo (1990). The last of those criteria `VQ7' concerns the possibility of remagnetization when a particular paleomagnetic pole resembles a younger paleopole from the same stable region. While remagnetizations are often the culprit, the mere resemblance of an older pole to a younger pole does not a priori require that the rocks under investigation are remagnetized. Given that the Earth has a finite surface area; that apparent polar wander paths are represented as wide swathes rather than points, and that continental motion has taken place over several billion years, we ask the question `How likely is it for an apparent polar wander path to loop back on itself?' To answer this question, we constructed synthetic apparent polar wander paths (APWPs) in an effort to evaluate the likelihood of self-intersection. We find that given 500 Myr of apparent polar wander, ˜60 per cent of the synthetic APWPs show self-intersection. Given 1000 Myr of apparent polar wander, ˜95 per cent of the synthetic APWPs show self-intersection. These results show that resemblance to younger paleopoles, over the long term, may be governed by simple probability rather than only remagnetization. We recognize that remagnetization does occur, sometimes pervasively, and must be reckoned with in the assessment of paleomagnetic data. Perhaps VQ7 should be amended to the first sentence in the original discussion (Van der Voo, 1990), and focus on satisfying `No suspicion of remagnetization' via other means rather than solely a resemblance to younger poles.

Patterns of gene expression in different histotypes of epithelial ovarian cancer correlate with those in normal fallopian tube, endometrium, and colon.

PubMed

Marquez, Rebecca T; Baggerly, Keith A; Patterson, Andrea P; Liu, Jinsong; Broaddus, Russell; Frumovitz, Michael; Atkinson, Edward N; Smith, David I; Hartmann, Lynn; Fishman, David; Berchuck, Andrew; Whitaker, Regina; Gershenson, David M; Mills, Gordon B; Bast, Robert C; Lu, Karen H

2005-09-01

Epithelial ovarian cancers are thought to arise from flattened epithelial cells that cover the ovarian surface or that line inclusion cysts. During malignant transformation, different histotypes arise that resemble epithelial cells from normal fallopian tube, endometrium, and intestine. This study compares gene expression in serous, endometrioid, clear cell, and mucinous ovarian cancers with that in the normal tissues that they resemble. Expression of 63,000 probe sets was measured in 50 ovarian cancers, in 5 pools of normal ovarian epithelial brushings, and in mucosal scrapings from 4 normal fallopian tube, 5 endometrium, and 4 colon specimens. Using rank-sum analysis, genes whose expressions best differentiated the ovarian cancer histotypes and normal ovarian epithelium were used to determine whether a correlation based on gene expression existed between ovarian cancer histotypes and the normal tissues they resemble. When compared with normal ovarian epithelial brushings, alterations in serous tumors correlated with those in normal fallopian tube (P = 0.0042) but not in other normal tissues. Similarly, mucinous cancers correlated with those in normal colonic mucosa (P = 0.0003), and both endometrioid and clear cell histotypes correlated with changes in normal endometrium (P = 0.0172 and 0.0002, respectively). Mucinous cancers displayed the greatest number of alterations in gene expression when compared with normal ovarian epithelial cells. Studies at a molecular level show distinct expression profiles of different histologies of ovarian cancer and support the long-held belief that histotypes of ovarian cancers come to resemble normal fallopian tube, endometrial, and colonic epithelium. Several potential molecular markers for mucinous ovarian cancers have been identified.

A novel protein-protein interaction in the RES (REtention and Splicing) complex.

PubMed

Tripsianes, Konstantinos; Friberg, Anders; Barrandon, Charlotte; Brooks, Mark; van Tilbeurgh, Herman; Seraphin, Bertrand; Sattler, Michael

2014-10-10

The retention and splicing (RES) complex is a conserved spliceosome-associated module that was shown to enhance splicing of a subset of transcripts and promote the nuclear retention of unspliced pre-mRNAs in yeast. The heterotrimeric RES complex is organized around the Snu17p protein that binds to both the Bud13p and Pml1p subunits. Snu17p exhibits an RRM domain that resembles a U2AF homology motif (UHM) and Bud13p harbors a Trp residue reminiscent of an UHM-ligand motif (ULM). It has therefore been proposed that the interaction between Snu17p and Bud13p resembles canonical UHM-ULM complexes. Here, we have used biochemical and NMR structural analysis to characterize the structure of the yeast Snu17p-Bud13p complex. Unlike known UHMs that sequester the Trp residue of the ULM ligand in a hydrophobic pocket, Snu17p and Bud13p utilize a large interaction surface formed around the two helices of the Snu17p domain. In total 18 residues of the Bud13p ligand wrap around the Snu17p helical surface in an U-turn-like arrangement. The invariant Trp(232) in Bud13p is located in the center of the turn, and contacts surface residues of Snu17p. The structural data are supported by mutational analysis and indicate that Snu17p provides an extended binding surface with Bud13p that is notably distinct from canonical UHM-ULM interactions. Our data highlight structural diversity in RRM-protein interactions, analogous to the one seen for nucleic acid interactions. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

Surfactant Behavior of Sodium Dodecylsulfate in Deep Eutectic Solvent Choline Chloride/Urea.

PubMed

Arnold, T; Jackson, A J; Sanchez-Fernandez, A; Magnone, D; Terry, A E; Edler, K J

2015-12-01

Deep eutectic solvents (DES) resemble ionic liquids but are formed from an ionic mixture instead of being a single ionic compound. Here we present some results that demonstrate that surfactant sodium dodecyl sulfate (SDS) remains surface-active and shows self-assembly phenomena in the most commonly studied DES, choline chloride/urea. X-ray reflectivity (XRR) and small angle neutron scattering (SANS) suggest that the behavior is significantly different from that in water. Our SANS data supports our determination of the critical micelle concentration using surface-tension measurements and suggests that the micelles formed in DES do not have the same shape and size as those seen in water. Reflectivity measurements have also demonstrated that the surfactants remain surface-active below this concentration.

Low work function silicon collector for thermionic converters

NASA Technical Reports Server (NTRS)

Chang, K. H.; Shimada, K.

1976-01-01

To improve the efficiency of present thermionic converters, single crystal silicon was investigated as a low work function collector material. The experiments were conducted in a test vehicle which resembled an actual thermionic converter. Work function as low as 1.0eV was obtained with an n-type silicon. The stabilities of the activated surfaces at elevated temperatures were tested by raising the collector temperature up to 829 K. By increasing the Cs arrival rate, it was possible to restore the originally activated low work function of the surface at elevated surface temperatures. These results, plotted in the form of Rasor-Warner curve, show a behavior similar to that of metal electrode except that the minimum work function was much lower with silicon than with metals.

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

Ballering, Nicholas P.; Rieke, George H.; Gáspár, András, E-mail: ballerin@email.arizona.edu

Observations of debris disks allow for the study of planetary systems, even where planets have not been detected. However, debris disks are often only characterized by unresolved infrared excesses that resemble featureless blackbodies, and the location of the emitting dust is uncertain due to a degeneracy with the dust grain properties. Here, we characterize the Spitzer Infrared Spectrograph spectra of 22 debris disks exhibiting 10 μm silicate emission features. Such features arise from small warm dust grains, and their presence can significantly constrain the orbital location of the emitting debris. We find that these features can be explained by themore » presence of an additional dust component in the terrestrial zones of the planetary systems, i.e., an exozodiacal belt. Aside from possessing exozodiacal dust, these debris disks are not particularly unique; their minimum grain sizes are consistent with the blowout sizes of their systems, and their brightnesses are comparable to those of featureless warm debris disks. These disks are in systems of a range of ages, though the older systems with features are found only around A-type stars. The features in young systems may be signatures of terrestrial planet formation. Analyzing the spectra of unresolved debris disks with emission features may be one of the simplest and most accessible ways to study the terrestrial regions of planetary systems.« less

Speech-feature discrimination in children with Asperger syndrome as determined with the multi-feature mismatch negativity paradigm.

PubMed

Kujala, T; Kuuluvainen, S; Saalasti, S; Jansson-Verkasalo, E; von Wendt, L; Lepistö, T

2010-09-01

Asperger syndrome, belonging to the autistic spectrum of disorders, involves deficits in social interaction and prosodic use of language but normal development of formal language abilities. Auditory processing involves both hyper- and hypoactive reactivity to acoustic changes. Responses composed of mismatch negativity (MMN) and obligatory components were recorded for five types of deviations in syllables (vowel, vowel duration, consonant, syllable frequency, syllable intensity) with the multi-feature paradigm from 8-12-year old children with Asperger syndrome. Children with Asperger syndrome had larger MMNs for intensity and smaller MMNs for frequency changes than typically developing children, whereas no MMN group differences were found for the other deviant stimuli. Furthermore, children with Asperger syndrome performed more poorly than controls in Comprehension of Instructions subtest of a language test battery. Cortical speech-sound discrimination is aberrant in children with Asperger syndrome. This is evident both as hypersensitive and depressed neural reactions to speech-sound changes, and is associated with features (frequency, intensity) which are relevant for prosodic processing. The multi-feature MMN paradigm, which includes variation and thereby resembles natural speech hearing circumstances, suggests abnormal pattern of speech discrimination in Asperger syndrome, including both hypo- and hypersensitive responses for speech features. 2010 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Similarity preserving low-rank representation for enhanced data representation and effective subspace learning.

PubMed

Zhang, Zhao; Yan, Shuicheng; Zhao, Mingbo

2014-05-01

Latent Low-Rank Representation (LatLRR) delivers robust and promising results for subspace recovery and feature extraction through mining the so-called hidden effects, but the locality of both similar principal and salient features cannot be preserved in the optimizations. To solve this issue for achieving enhanced performance, a boosted version of LatLRR, referred to as Regularized Low-Rank Representation (rLRR), is proposed through explicitly including an appropriate Laplacian regularization that can maximally preserve the similarity among local features. Resembling LatLRR, rLRR decomposes given data matrix from two directions by seeking a pair of low-rank matrices. But the similarities of principal and salient features can be effectively preserved by rLRR. As a result, the correlated features are well grouped and the robustness of representations is also enhanced. Based on the outputted bi-directional low-rank codes by rLRR, an unsupervised subspace learning framework termed Low-rank Similarity Preserving Projections (LSPP) is also derived for feature learning. The supervised extension of LSPP is also discussed for discriminant subspace learning. The validity of rLRR is examined by robust representation and decomposition of real images. Results demonstrated the superiority of our rLRR and LSPP in comparison to other related state-of-the-art algorithms. Copyright © 2014 Elsevier Ltd. All rights reserved.

Surface properties for α-cluster nuclear matter

NASA Astrophysics Data System (ADS)

Castro, J. J.; Soto, J. R.; Yépez, E.

2013-03-01

We introduce a new microscopic model for α-cluster matter, which simulates the properties of ordinary nuclear matter and α-clustering in a curved surface of a large but finite nucleus. The model is based on a nested icosahedral fullerene-like multiple-shell structure, where each vertex is occupied by a microscopic α-particle. The novel aspect of this model is that it allows a consistent description of nuclear surface properties from microscopic parameters to be made without using the leptodermous expansion. In particular, we show that the calculated surface energy is in excellent agreement with the corresponding coefficient of the Bethe-Weizäcker semi-empirical mass formula. We discuss the properties of the surface α-cluster state, which resembles an ultra cold bosonic quantum gas trapped in an optical lattice. By comparing the surface and interior states we are able to estimate the α preformation probability. Possible extensions of this model to study nuclear dynamics through surface vibrations and departures from approximate sphericity are mentioned.

Origins of Folding Instabilities on Polycrystalline Metal Surfaces

NASA Astrophysics Data System (ADS)

Beckmann, N.; Romero, P. A.; Linsler, D.; Dienwiebel, M.; Stolz, U.; Moseler, M.; Gumbsch, P.

2014-12-01

Wear and removal of material from polycrystalline metal surfaces is inherently connected to plastic flow. Here, plowing-induced unconstrained surface plastic flow on a nanocrystalline copper surface has been studied by massive molecular dynamics simulations and atomic force microscopy scratch experiments. In agreement with experimental findings, bulges in front of a model asperity develop into vortexlike fold patterns that mark the disruption of laminar flow. We identify dislocation-mediated plastic flow in grains with suitably oriented slip systems as the basic mechanism of bulging and fold formation. The observed folding can be fundamentally explained by the inhomogeneity of plasticity on polycrystalline surfaces which favors bulge formation on grains with suitably oriented slip system. This process is clearly distinct from Kelvin-Helmholtz instabilities in fluids, which have been previously suggested to resemble the formed surface fold patterns. The generated prow grows into a rough chip with stratified lamellae that are identified as the precursors of wear debris. Our findings demonstrate the importance of surface texture and grain structure engineering to achieve ultralow wear in metals.

A lack of Birbeck granules in Langerhans cells is associated with a naturally occurring point mutation in the human Langerin gene.

PubMed

Verdijk, Pauline; Dijkman, Remco; Plasmeijer, Elsemieke I; Mulder, Aat A; Zoutman, Willem H; Mieke Mommaas, A; Tensen, Cornelis P

2005-04-01

A heterozygous mutation in the Langerin gene corresponding to position 837 in the Langerin mRNA was identified in a person deficient in Birbeck granules (BG). This mutation results in an amino acid replacement of tryptophan by arginine at position 264 in the carbohydrate recognition domain of the Langerine protein. Expression of mutated Langerin in human fibroblasts induces tubular-like structures that are negative for BG-specific antibodies and do not resemble the characteristic structural features of BG.

Biomimetic Materials by Freeze Casting

NASA Astrophysics Data System (ADS)

Porter, Michael M.; Mckittrick, Joanna; Meyers, Marc A.

2013-06-01

Natural materials, such as bone and abalone nacre, exhibit exceptional mechanical properties, a product of their intricate microstructural organization. Freeze casting is a relatively simple, inexpensive, and adaptable materials processing method to form porous ceramic scaffolds with controllable microstructural features. After infiltration of a second polymeric phase, hybrid ceramic-polymer composites can be fabricated that closely resemble the architecture and mechanical performance of natural bone and nacre. Inspired by the narwhal tusk, magnetic fields applied during freeze casting can be used to further control architectural alignment, resulting in freeze-cast materials with enhanced mechanical properties.

Focal cemento-osseous dysplasia masquerading as a residual cyst

PubMed Central

Bhandari, Rajat; Sandhu, Simarpreet V.; Bansal, Himanta; Behl, Rashi; Bhullar, Ramanpreet Kaur

2012-01-01

Focal cemento-osseous dysplasia (FCOD) is a benign fibroosseous condition that can be seen in dentulous and edentulous patients. It is an asymptomatic lesion and needs no treatment; however, follow-up is essential due to the possibility that it can progress to a condition called florid cemento-osseous dysplasia. We report a case of FCOD of mandible in a 25-year-old female. Clinically, the lesion resembled periapical pathosis of odontogenic origin. An attempt has been made to discuss the clinical and histopathologic features along with differential diagnosis of cemento-osseous dysplasia. PMID:22629069

Focal cemento-osseous dysplasia masquerading as a residual cyst.

PubMed

Bhandari, Rajat; Sandhu, Simarpreet V; Bansal, Himanta; Behl, Rashi; Bhullar, Ramanpreet Kaur

2012-04-01

Focal cemento-osseous dysplasia (FCOD) is a benign fibroosseous condition that can be seen in dentulous and edentulous patients. It is an asymptomatic lesion and needs no treatment; however, follow-up is essential due to the possibility that it can progress to a condition called florid cemento-osseous dysplasia. We report a case of FCOD of mandible in a 25-year-old female. Clinically, the lesion resembled periapical pathosis of odontogenic origin. An attempt has been made to discuss the clinical and histopathologic features along with differential diagnosis of cemento-osseous dysplasia.

Aeolian Features of Scandia Cavi

NASA Image and Video Library

2015-09-30

This image from NASA Mars Reconnaissance Orbiter spacecraft shows modified barchan dunes with shapes that resemble raptor claws. The unusual morphology of these dunes suggests a limited supply of windblown sand. Winds likely blew from the northeast resulting in elongate dunes with an asymmetric downwind point. The transverse crests of the smaller ripples/mega-ripple bed-forms surrounding the dune, echo the dominant downwind direction towards the southwest. This locality is in the Northern Lowlands directly east of Dokka Crater in Scandia Cavi. http://photojournal.jpl.nasa.gov/catalog/PIA19962

Morphing Carbon Nanotube Microstructures

DTIC Science & Technology

2015-02-20

most fibrous nanoscale aerogels and foams, having n=2-3, which is attributed to 2 low connectivity between the constituent struts 7. When comparing...CNTs incidentally resembles the Young’s moduli of isotropic CNT foams 30, CNT aerogels 31, and Si aerogels 32 which scale as ~ρ3, and commonly...characteristics of ultrahigh surface area single-walled carbon nanotube aerogels . Adv. Funct. Mater. 23, 377-383 (2013). 8. R. M. German, Sintering

Melorheostosis – Case Report of Rare Disease

PubMed Central

Kumar, Rakesh; Sankhala, S.S.; Bijarnia, Isha

2014-01-01

Introduction: Melorheostosis(synonyms: candle bone disease, melting wax syndrome, Leri disease) is a rare chronic bone disorder, first described in 1922 by Leri and Joanny. Men and women are equally affected, and no hereditary features have been discovered. Onset is insidious, and most common symptom is pain. Most common part of bone is diaphysis of the long bone of lower limb rarely the axial skeleton. Classical radiological appearance of ’flowing hyperosteosis’ resembling hardened wax that has dripped down the side of a candle. Case Report: A 35 years old woman presented with left leg pain with mild swelling and limitation of knee movement. On examination non tender bony heard swelling, hyperpigmented and restriction of knee movement present. Plain radiographs showed extensive, dense, undulating or irregular cortical hyperostosis, resembling candle wax, extending along the length of bone. Pamidronate as well asanalgesic were given to the patient. Physiotherepy started for the deformity. Conclusion: Routine laboratory findings usually are normal. The exact cause remain unclear. There is no definite treatment available for this disease. Only symptomatic treatment improve the condition of the patients, more fruitful result obtain with pamidronate and physiotherapy. PMID:27298954

Resting-state fMRI in sleeping infants more closely resembles adult sleep than adult wakefulness

PubMed Central

Snyder, Abraham Z.; Tagliazucchi, Enzo; Laufs, Helmut; Elison, Jed; Emerson, Robert W.; Shen, Mark D.; Wolff, Jason J.; Botteron, Kelly N.; Dager, Stephen; Estes, Annette M.; Evans, Alan; Gerig, Guido; Hazlett, Heather C.; Paterson, Sarah J.; Schultz, Robert T.; Styner, Martin A.; Zwaigenbaum, Lonnie; Schlaggar, Bradley L.

2017-01-01

Resting state functional magnetic resonance imaging (rs-fMRI) in infants enables important studies of functional brain organization early in human development. However, rs-fMRI in infants has universally been obtained during sleep to reduce participant motion artifact, raising the question of whether differences in functional organization between awake adults and sleeping infants that are commonly attributed to development may instead derive, at least in part, from sleep. This question is especially important as rs-fMRI differences in adult wake vs. sleep are well documented. To investigate this question, we compared functional connectivity and BOLD signal propagation patterns in 6, 12, and 24 month old sleeping infants with patterns in adult wakefulness and non-REM sleep. We find that important functional connectivity features seen during infant sleep closely resemble those seen during adult sleep, including reduced default mode network functional connectivity. However, we also find differences between infant and adult sleep, especially in thalamic BOLD signal propagation patterns. These findings highlight the importance of considering sleep state when drawing developmental inferences in infant rs-fMRI. PMID:29149191

Phenotype-genotype discordance in congenital malformations with communication disorders resembling trisomy 18 (Edwards syndrome)

PubMed Central

Pruszewicz, Antoni; Wiskirska-Woźnica, Bożena; Wojnowski, Waldemar; Czerniejewska, Hanna; Jackowska, Joanna; Jarmuż, Małgorzata; Szyfter, Krzysztof; Leszczyńska, Małgorzata

2014-01-01

Patient: Female, 6 Final Diagnosis: Phenotype-genotype discordance in congenital malformations with communication disorders resembling trisomy 18 (Edwards syndrome) Symptoms: — Medication: — Clinical Procedure: — Specialty: Otolaryngology Objective: Congenital defects Background: Communication process disorders are very frequent in rare cases of chromosomal aberrations (deletions, insertions, and trisomies) such as Down syndrome (trisomy 21), Turner syndrome, Edwards syndrome (trisomy 18), or Patau syndrome (trisomy 13). Sometimes phenotype may delusively correspond to the characteristic features of a given syndrome, but genotype tests do not confirm its presence. Case Report: We present the case of a 6-year-old girl admitted to the Clinic of Phoniatrics and Audiology for the assessment of communication in the course of congenital malformations with phenotype characteristic for trisomy 18 (Edwards syndrome). Immediately upon birth, dysmorphic changes suggesting trisomy 18 (Edwards syndrome) were observed, but trisomy 18 was excluded after karyotype test results were normal (46, XX). Conclusions: Disturbed articulation was diagnosed: deformed linguo-dental and palatal sounds, interdental realization with flat tongue of the /s/, /z/, /c/, /dz/, /ś/, /ź/, /ć/, /dz/ sounds (sigmatismus interdentalis). Hearing loss was confirmed. PMID:24478819

Resting-state fMRI in sleeping infants more closely resembles adult sleep than adult wakefulness.

PubMed

Mitra, Anish; Snyder, Abraham Z; Tagliazucchi, Enzo; Laufs, Helmut; Elison, Jed; Emerson, Robert W; Shen, Mark D; Wolff, Jason J; Botteron, Kelly N; Dager, Stephen; Estes, Annette M; Evans, Alan; Gerig, Guido; Hazlett, Heather C; Paterson, Sarah J; Schultz, Robert T; Styner, Martin A; Zwaigenbaum, Lonnie; Schlaggar, Bradley L; Piven, Joseph; Pruett, John R; Raichle, Marcus

2017-01-01

Resting state functional magnetic resonance imaging (rs-fMRI) in infants enables important studies of functional brain organization early in human development. However, rs-fMRI in infants has universally been obtained during sleep to reduce participant motion artifact, raising the question of whether differences in functional organization between awake adults and sleeping infants that are commonly attributed to development may instead derive, at least in part, from sleep. This question is especially important as rs-fMRI differences in adult wake vs. sleep are well documented. To investigate this question, we compared functional connectivity and BOLD signal propagation patterns in 6, 12, and 24 month old sleeping infants with patterns in adult wakefulness and non-REM sleep. We find that important functional connectivity features seen during infant sleep closely resemble those seen during adult sleep, including reduced default mode network functional connectivity. However, we also find differences between infant and adult sleep, especially in thalamic BOLD signal propagation patterns. These findings highlight the importance of considering sleep state when drawing developmental inferences in infant rs-fMRI.

What you fear will appear: detection of schematic spiders in spider fear.

PubMed

Peira, Nathalie; Golkar, Armita; Larsson, Maria; Wiens, Stefan

2010-01-01

Various experimental tasks suggest that fear guides attention. However, because these tasks often lack ecological validity, it is unclear to what extent results from these tasks can be generalized to real-life situations. In change detection tasks, a brief interruption of the visual input (i.e., a blank interval or a scene cut) often results in undetected changes in the scene. This setup resembles real-life viewing behavior and is used here to increase ecological validity of the attentional task without compromising control over the stimuli presented. Spider-fearful and nonfearful women detected schematic spiders and flowers that were added to one of two identical background pictures that alternated with a brief blank in between them (i.e., flicker paradigm). Results showed that spider-fearful women detected spiders (but not flowers) faster than did nonfearful women. Because spiders and flowers had similar low-level features, these findings suggest that fear guides attention on the basis of object features rather than simple low-level features.

Cockayne syndrome: Clinical features, model systems and pathways

PubMed Central

Karikkineth, Ajoy C.; Scheibye-Knudsen, Morten; Fivenson, Elayne; Croteau, Deborah L.; Bohr, Vilhelm A.

2016-01-01

Cockayne syndrome (CS) is a disorder characterized by a variety of clinical features including cachectic dwarfism, severe neurological manifestations including microcephaly and cognitive deficits, pigmentary retinopathy, cataracts, sensorineural deafness, and ambulatory and feeding difficulties, leading to death by 12 years of age on average. It is an autosomal recessive disorder, with a prevalence of approximately 2.5 per million. There are several phenotypes (1, 2 and 3) and complementation groups (CSA and CSB), and overlaps with xeroderma pigmentosum (XP). It has been considered a progeria, and many of the clinical features resemble accelerated aging. As such, the study of CS affords an opportunity to better understand the underlying mechanisms of aging. The molecular basis of CS has traditionally been considered to be due to defects in transcription and transcription-coupled nucleotide excision repair (TC-NER). However, recent work suggests that defects in base excision DNA repair and mitochondrial functions may also play key roles. This opens up the possibility of molecular interventions in CS, and by extrapolation, possibly in aging. PMID:27507608

Bioengineered Tooth Buds Exhibit Features of Natural Tooth Buds.

PubMed

Smith, E E; Angstadt, S; Monteiro, N; Zhang, W; Khademhosseini, A; Yelick, P C

2018-06-01

Tooth loss is a significant health issue currently affecting millions of people worldwide. Artificial dental implants, the current gold standard tooth replacement therapy, do not exhibit many properties of natural teeth and can be associated with complications leading to implant failure. Here we propose bioengineered tooth buds as a superior alternative tooth replacement therapy. We describe improved methods to create highly cellularized bioengineered tooth bud constructs that formed hallmark features that resemble natural tooth buds such as the dental epithelial stem cell niche, enamel knot signaling centers, transient amplifying cells, and mineralized dental tissue formation. These constructs were composed of postnatal dental cells encapsulated within a hydrogel material that were implanted subcutaneously into immunocompromised rats. To our knowledge, this is the first report describing the use of postnatal dental cells to create bioengineered tooth buds that exhibit evidence of these features of natural tooth development. We propose future bioengineered tooth buds as a promising, clinically relevant tooth replacement therapy.

Behavioural and neurobiological implications of linear and non-linear features in larynx phonations of horseshoe bats

PubMed Central

Kobayasi, Kohta I.; Hage, Steffen R.; Berquist, Sean; Feng, Jiang; Zhang, Shuyi; Metzner, Walter

2012-01-01

Mammalian vocalizations exhibit large variations in their spectrotemporal features, although it is still largely unknown which result from intrinsic biomechanical properties of the larynx and which are under direct neuromuscular control. Here we show that mere changes in laryngeal air flow yield several non-linear effects on sound production, in an isolated larynx preparation from horseshoe bats. Most notably, there are sudden jumps between two frequency bands used for either echolocation or communication in natural vocalizations. These jumps resemble changes in “registers” as in yodelling. In contrast, simulated contractions of the main larynx muscle produce linear frequency changes, but are limited to echolocation or communication frequencies. Only by combining non-linear and linear properties can this larynx therefore produce sounds covering the entire frequency range of natural calls. This may give behavioural meaning to yodelling-like vocal behaviour and reshape our thinking about how the brain controls the multitude of spectral vocal features in mammals. PMID:23149729

New Science in Plain Sight: Optical Manifestations of Coupled Subauroral Features Documented by Citizen Scientists

NASA Astrophysics Data System (ADS)

MacDonald, E.; Heavner, M.; Kosar, B.; Case, N.; Donovan, E.; Spanswick, E.; Nishimura, Y.; Gallardo-Lacourt, B.

2017-12-01

Aurora has been observed and recorded by people for thousands of years. Recently, citizen scientists captured features of aurora-like arc events not previously described in the literature at subauroral latitudes. Amateur photo sequences show unusual flow, unstable composition changes, and field aligned structures. Observations from the Swarm satellite crossing the arc reveals thermal enhancement, density depletion, and strong westward ion flow. These signatures resemble features previously described from in situ observation however the optical manifestation is surprising and contains rich, unstable signatures as well. The relevant observations have presented important implications on a variety of open questions, including the fundamental definition of aurora, and limitations of jargon and subfield distinctions. This paper covers the discovery, its context, and the significant implications for the application of public participation measurement modes to the natural sciences whereby they can form a disruptive gap to expose new observing perspectives. Photo Credit: Notanee Bourassa, Alberta Aurora Chasers

Features on Venus generated by plate boundary processes

NASA Technical Reports Server (NTRS)

Mckenzie, Dan; Ford, Peter G.; Johnson, Catherine; Parsons, Barry; Sandwell, David; Saunders, Stephen; Solomon, Sean C.

1992-01-01

Various observations suggest that there are processes on Venus that produce features similar to those associated with plate boundaries on earth. Synthetic aperture radar images of Venus, taken with a radar whose wavelength is 12.6 cm, are compared with GLORIA images of active plate boundaries, obtained with a sound source whose wavelength is 23 cm. Features similar to transform faults and to abyssal hills on slow and fast spreading ridges can be recognized within the Artemis region of Venus but are not clearly visible elsewhere. The composition of the basalts measured by the Venera 13 and 14 and the Vega 2 spacecraft corresponds to that expected from adiabatic decompression, like that which occurs beneath spreading ridges on earth. Structures that resemble trenches are widespread on Venus and show the same curvature and asymmetry as they do on earth. These observations suggest that the same simple geophysical models that have been so successfully used to understand the tectonics of earth can also be applied to Venus.

The vertebral remains of the late Miocene great ape Hispanopithecus laietanus from Can Llobateres 2 (Vallès-Penedès Basin, NE Iberian Peninsula).

PubMed

Susanna, Ivette; Alba, David M; Almécija, Sergio; Moyà-Solà, Salvador

2014-08-01

Here we describe the vertebral fragments from the partial skeleton IPS18800 of the fossil great ape Hispanopithecus laietanus (Hominidae: Dryopithecinae) from the late Miocene (9.6 Ma) of Can Llobateres 2 (Vallès-Penedès Basin, Catalonia, Spain). The eight specimens (IPS18800.5-IPS18800.12) include a fragment of thoracic vertebral body, three partial bodies and four neural arch fragments of lumbar vertebrae. Despite the retention of primitive features (moderately long lumbar vertebral bodies with slightly concave ventrolateral sides), these specimens display a suite of derived, modern hominoid-like features: thoracic vertebrae with dorsally-situated costal foveae; lumbar vertebrae with non-ventrally-oriented transverse processes originating from a robust pedicle, caudally-long laminae with caudally-oriented spinous process, elliptical end-plates, and moderately stout bodies reduced in length and with no ventral keel. These features, functionally related to orthograde behaviors, are indicative of a broad and shallow thorax with a moderately short and stiff lumbar region in Hispanopithecus. Despite its large body mass (ca. 39-40 kg), its vertebral morphology is more comparable to that of hylobatids and Ateles than to extant great apes. This is confirmed by our morphometric analyses, also indicating that Hispanopithecus most closely resembles Pierolapithecus and Morotopithecus among Miocene apes, whereas Proconsul and Nacholapithecus resemble pronograde monkeys. Only in a few features (craniocaudally short and transversely wide pedicles, transverse processes situated on the pedicle, and slight ventral wedging), Hispanopithecus is more derived towards the extant great ape condition than other Miocene apes. Overall, the vertebral morphology of Hispanopithecus supports previous inferences of an orthograde body plan with suspensory and climbing adaptations. However, given similarities with Ateles and the retention of a longer and more flexible spine than in extant great apes, the Hispanopithecus morphology is also consistent with some degree of above-branch quadrupedalism, as previously inferred from other anatomical regions. Copyright © 2014 Elsevier Ltd. All rights reserved.

Distinct clinical and neuropathological features of G51D SNCA mutation cases compared with SNCA duplication and H50Q mutation.

PubMed

Kiely, Aoife P; Ling, Helen; Asi, Yasmine T; Kara, Eleanna; Proukakis, Christos; Schapira, Anthony H; Morris, Huw R; Roberts, Helen C; Lubbe, Steven; Limousin, Patricia; Lewis, Patrick A; Lees, Andrew J; Quinn, Niall; Hardy, John; Love, Seth; Revesz, Tamas; Houlden, Henry; Holton, Janice L

2015-08-27

We and others have described the neurodegenerative disorder caused by G51D SNCA mutation which shares characteristics of Parkinson's disease (PD) and multiple system atrophy (MSA). The objective of this investigation was to extend the description of the clinical and neuropathological hallmarks of G51D mutant SNCA-associated disease by the study of two additional cases from a further G51D SNCA kindred and to compare the features of this group with a SNCA duplication case and a H50Q SNCA mutation case. All three G51D patients were clinically characterised by parkinsonism, dementia, visual hallucinations, autonomic dysfunction and pyramidal signs with variable age at disease onset and levodopa response. The H50Q SNCA mutation case had a clinical picture that mimicked late-onset idiopathic PD with a good and sustained levodopa response. The SNCA duplication case presented with a clinical phenotype of frontotemporal dementia with marked behavioural changes, pyramidal signs, postural hypotension and transiently levodopa responsive parkinsonism. Detailed post-mortem neuropathological analysis was performed in all cases. All three G51D cases had abundant α-synuclein pathology with characteristics of both PD and MSA. These included widespread cortical and subcortical neuronal α-synuclein inclusions together with small numbers of inclusions resembling glial cytoplasmic inclusions (GCIs) in oligodendrocytes. In contrast the H50Q and SNCA duplication cases, had α-synuclein pathology resembling idiopathic PD without GCIs. Phosphorylated α-synuclein was present in all inclusions types in G51D cases but was more restricted in SNCA duplication and H50Q mutation. Inclusions were also immunoreactive for the 5G4 antibody indicating their highly aggregated and likely fibrillar state. Our characterisation of the clinical and neuropathological features of the present small series of G51D SNCA mutation cases should aid the recognition of this clinico-pathological entity. The neuropathological features of these cases consistently share characteristics of PD and MSA and are distinct from PD patients carrying the H50Q or SNCA duplication.

Cooling of the North Atlantic by Saharan Dust

NASA Technical Reports Server (NTRS)

Lau, K. M.; Kim, K. M.

2007-01-01

Using aerosol optical depth, sea surface temperature, top-of-the-atmosphere solar radiation flux, and oceanic mixed-layer depth from diverse data sources that include NASA satellites, NCEP reanalysis, in situ observations, as well as long-term dust records from Barbados, we examine the possible relationships between Saharan dust and Atlantic sea surface temperature. Results show that the estimated anomalous cooling pattern of the Atlantic during June 2006 relative to June 2005 due to attenuation of surface solar radiation by Saharan dust remarkably resemble observations, accounting for approximately 30-40% of the observed change in sea surface temperature. Historical data analysis show that there is a robust negative correlation between atmospheric dust loading and Atlantic SST consistent with the notion that increased (decreased) Saharan dust is associated with cooling (warming) of the Atlantic during the early hurricane season (July- August-September).

Slippery liquid-infused porous surfaces having improved stability

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

Aizenberg, Joanna; Vogel, Nicolas

Methods and articles disclosed herein relate to liquid repellant surfaces having selective wetting and transport properties. An article having a repellant surface includes a substrate comprising surface features with re-entrant curvature and an immobilized layer of lubricating liquid wetting over the surface features. The surface features with re-entrant curvature can be designed to provide high repellency even after failure or removal of the immobilized layer of lubricating liquid under certain operating conditions.

Middle Pleistocene Hominin Teeth from Longtan Cave, Hexian, China

PubMed Central

Xing, Song; Martinón-Torres, María; Bermúdez de Castro, José María; Zhang, Yingqi; Fan, Xiaoxiao; Zheng, Longting; Huang, Wanbo; Liu, Wu

2014-01-01

Excavations at the Longtan Cave, Hexian, Anhui Province of Eastern China, have yielded several hominin fossils including crania, mandibular fragments, and teeth currently dated to 412±25 ka. While previous studies have focused on the cranial remains, there are no detailed analyses of the dental evidence. In this study, we provide metric and morphological descriptions and comparisons of ten teeth recovered from Hexian, including microcomputed tomography analyses. Our results indicate that the Hexian teeth are metrically and morphologically primitive and overlap with H. ergaster and East Asian Early and mid-Middle Pleistocene hominins in their large dimensions and occlusal complexities. However, the Hexian teeth differ from H. ergaster in features such as conspicuous vertical grooves on the labial/buccal surfaces of the central incisor and the upper premolar, the crown outline shapes of upper and lower molars and the numbers, shapes, and divergences of the roots. Despite their close geological ages, the Hexian teeth are also more primitive than Zhoukoudian specimens, and resemble Sangiran Early Pleistocene teeth. In addition, no typical Neanderthal features have been identified in the Hexian sample. Our study highlights the metrical and morphological primitive status of the Hexian sample in comparison to contemporaneous or even earlier populations of Asia. Based on this finding, we suggest that the primitive-derived gradients of the Asian hominins cannot be satisfactorily fitted along a chronological sequence, suggesting complex evolutionary scenarios with the coexistence and/or survival of different lineages in Eurasia. Hexian could represent the persistence in time of a H. erectus group that would have retained primitive features that were lost in other Asian populations such as Zhoukoudian or Panxian Dadong. Our study expands the metrical and morphological variations known for the East Asian hominins before the mid-Middle Pleistocene and warns about the possibility that the Asian hominin variability may have been taxonomically oversimplified. PMID:25551383

Windblown Features on Venus and Geological Mapping

NASA Technical Reports Server (NTRS)

Greeley, Ronald

1999-01-01

The objectives of this study were to: 1) develop a global data base of aeolian features by searching Magellan coverage for possible time-variable wind streaks, 2) analyze the data base to characterize aeolian features and processes on Venus, 3) apply the analysis to assessments of wind patterns near the surface and for comparisons with atmospheric circulation models, 4) analyze shuttle radar data acquired for aeolian features on Earth to determine their radar characteristics, and 5) conduct geological mapping of two quadrangles. Wind, or aeolian, features are observed on Venus and aeolian processes play a role in modifying its surface. Analysis of features resulting from aeolian processes provides insight into characteristics of both the atmosphere and the surface. Wind related features identified on Venus include erosional landforms (yardangs), depositional dune fields, and features resulting from the interaction of the atmosphere and crater ejecta at the time of impact. The most abundant aeolian features are various wind streaks. Their discovery on Venus afforded the opportunity to learn about the interaction of the atmosphere and surface, both for the identification of sediments and in mapping near-surface winds.

Slowly progressive aphasia associated with surface dyslexia.

PubMed

Chiacchio, L; Grossi, D; Stanzione, M; Trojano, L

1993-03-01

We report an Italian patient affected by slowly progressive aphasia (SPA) lasting since four years when he first came to our observation. During the successive four years, we documented a progressive language decline resembling transcortical sensory aphasia, associated with a reading disorder corresponding to surface dyslexia, a form extremely rare in patients with native transparent language. His performance at standard intelligence tasks remained in the normal range, without any variation. CT scan showed left temporal atrophy. We emphasize the heterogeneity of the syndrome of SPA and suggest that it can represent one of the pictures of focal cortical degenerative disease, with variable onset, progression, and evolution.

Water walking - an evolution of water surface skipping

NASA Astrophysics Data System (ADS)

Hurd, Randy; Belden, Jesse; Jandron, Michael; Bower, Allan; Holekamp, Sean; Truscott, Tadd

2017-11-01

Previous work has shown that elastomeric spheres skip more easily than disk-shaped stones. This is due to increased lift stemming from sphere deformation, which provides an increased cross-sectional area and favorable attack angle upon impact. We extend lift models developed for individual impacts to long-range multiple impact events and compare the estimates to experimental results, which show good agreement. Additionally, a surprising new mode of skipping is observed that resembles water-walking, wherein a quickly rotating sphere produces small successive impacts allowing it to move parallel to the water surface. The dynamics of this new multiple skip behavior are rationalized analytically and tested experimentally.

The nanophase iron mineral(s) in Mars soil

NASA Technical Reports Server (NTRS)

Banin, A.; Ben-Shlomo, T.; Margulies, L.; Blake, D. F.; Gehring, A. U.

1992-01-01

Iron-enriched smectites have been suggested as important mineral compounds of the Martian soil. They were shown to comply with the chemical analysis of the Martian soil, to simulate many of the findings of the Viking Labeled Release Experiments on Mars, to have spectral reflectance in the VIS-NIR strongly resembling the bright regions on Mars. The analogy with Mars soil is based, in a number of aspects, on the nature and behavior of the iron oxides and oxyhydroxides deposited on the surface of the clay particles. A summary of the properties of these iron phases and some recent findings are presented. Their potential relevance to Mars surface processes is discussed.

Composite, nanostructured, super-hydrophobic material

DOEpatents

D'Urso, Brian R [Clinton, TN; Simpson, John T [Clinton, TN

2007-08-21

A hydrophobic disordered composite material having a protrusive surface feature includes a recessive phase and a protrusive phase, the recessive phase having a higher susceptibility to a preselected etchant than the protrusive phase, the composite material having an etched surface wherein the protrusive phase protrudes from the surface to form a protrusive surface feature, the protrusive feature being hydrophobic.

Summers with low Arctic sea ice linked to persistence of spring atmospheric circulation patterns

NASA Astrophysics Data System (ADS)

Kapsch, Marie-Luise; Skific, Natasa; Graversen, Rune G.; Tjernström, Michael; Francis, Jennifer A.

2018-05-01

The declining trend of Arctic September sea ice constitutes a significant change in the Arctic climate system. Large year-to-year variations are superimposed on this sea-ice trend, with the largest variability observed in the eastern Arctic Ocean. Knowledge of the processes important for this variability may lead to an improved understanding of seasonal and long-term changes. Previous studies suggest that transport of heat and moisture into the Arctic during spring enhances downward surface longwave radiation, thereby controlling the annual melt onset, setting the stage for the September ice minimum. In agreement with these studies, we find that years with a low September sea-ice concentration (SIC) are characterized by more persistent periods in spring with enhanced energy flux to the surface in forms of net longwave radiation plus turbulent fluxes, compared to years with a high SIC. Two main atmospheric circulation patterns related to these episodes are identified: one resembles the so-called Arctic dipole anomaly that promotes transport of heat and moisture from the North Pacific, whereas the other is characterized by negative geopotential height anomalies over the Arctic, favoring cyclonic flow from Siberia and the Kara Sea into the eastern Arctic Ocean. However, differences between years with low and high September SIC appear not to be due to different spring circulation patterns; instead it is the persistence and intensity of processes associated with these patterns that distinguish the two groups of anomalous years: Years with low September SIC feature episodes that are consistently stronger and more persistent than years with high SIC.

Geology and Origin of Europa's Mitten Feature (Murias Chaos)

NASA Technical Reports Server (NTRS)

Figueredo, P. H.; Chuang, F. C.; Rathbun, J.; Kirk, R. L.; Greeley, R.

2002-01-01

The "Mitten" (provisionally named Murias Chaos by the International Astronomical Union) is a region of elevated chaos-like terrain in the leading hemisphere of Europa. Its origin had been explained under the currently debated theories of melting through a thin lithosphere or convection within a thick one. Galileo observations reveal several characteristics that suggest that the Mitten is distinct from typical chaos terrain and point to a different formational process. Photoclinometric elevation estimates suggest that the Mitten is slightly elevated with respect to the surrounding terrain; geologic relations indicate that it must have raised significantly from the plains in its past, resembling disrupted domes on Europa's trailing hemisphere. Moreover, the Mitten material appears to have extruded onto the plains and flowed for tens of kilometers. The area subsequently subsided as a result of isostatic adjustment, viscous relaxation, and/or plains loading. Using plate flexure models, we estimated the elastic lithosphere in the area to be several kilometers thick. We propose that the Mitten originated by the ascent and extrusion of a large thermal diapir. Thermal-mechanical modeling shows that a Mitten-sized plume would remain sufficiently warm and buoyant to pierce through the crust and flow unconfined on the surface. Such a diapir probably had an initial radius between 5 and 8 km and an initial depth of 20-40 km, consistent with a thick-lithosphere model. In this scenario the Mitten appears to represent the surface expression of the rare ascent of a large diapir, in contrast to lenticulae and chaos terrain, which may form by isolated and clustered small diapirs, respectively.

Geology and origin of Europa's "Mitten" feature (Murias Chaos)

USGS Publications Warehouse

Figueredo, P.H.; Chuang, F.C.; Rathbun, J.; Kirk, R.L.; Greeley, R.

2002-01-01

The "Mitten" (provisionally named Murias Chaos by the International Astronomical Union) is a region of elevated chaos-like terrain in the leading hemisphere of Europa. Its origin had been explained under the currently debated theories of melting through a thin lithosphere or convection within a thick one. Galileo observations reveal several characteristics that suggest that the Mitten is distinct from typical chaos terrain and point to a different formational process. Photoclinometric elevation estimates suggest that the Mitten is slightly elevated with respect to the surrounding terrain; geologic relations indicate that it must have raised significantly from the plains in its past, resembling disrupted domes on Europa's trailing hemisphere. Moreover, the Mitten material appears to have extruded onto the plains and flowed for tens of kilometers. The area subsequently subsided as a result of isostatic adjustment, viscous relaxation, and/or plains loading. Using plate flexure models, we estimated the elastic lithosphere in the area to be several kilometers thick. We propose that the Mitten originated by the ascent and extrusion of a large thermal diapir. Thermal-mechanical modeling shows that a Mitten-sized plume would remain sufficiently warm and buoyant to pierce through the crust and flow unconfined on the surface. Such a diapir probably had an initial radius between 5 and 8 km and an initial depth of 20-40 km, consistent with a thick-lithosphere model. In this scenario the Mitten appears to represent the surface expression of the rare ascent of a large diapir, in contrast to lenticulae and chaos terrain, which may form by isolated and clustered small diapirs, respectively.

Ultrastructure of the anterior organ and posterior funnel-shaped canal of Gyrocotyle urna Wagener, 1852 (Cestoda: Gyrocotylidea).

PubMed

Poddubnaya, Larisa G; Kuchta, Roman; Bristow, Glenn A; Scholz, Tomas

2015-05-22

Using scanning and transmission electron microscopy, ultrastructure of the anterior organ and posterior funnel-shaped canal of Gyrocotyle urna Wagener, 1852 (Cestoda: Gyrocotylidea) from ratfish, Chimaera monstrosa (Holocephali), was studied for the first time. The proper anterior organ is localised at a short distance (about 170 µm) from an apical pore surrounded by a receptor field, whereas its distal end is marked by a muscular sphincter. The tegumental surface of this organ is covered with short filitriches of irregular length; large area of muscle layers traverse beneath the tegumental layer. The funnel-shaped canal of G. urna (2.5-3.0 mm long) is a specialised, muscular part of the posterior attachment organ; it opens on the rounded elevation on the dorsal body surface. The tegumental layer bears conical sclerite-like structures (up to 1.5 µm long). It produces electron-dense bodies that are transported into a canal lumen and surrounded thick muscle area mixed with numerous nerve fibres. The present ultrastructural study of G. urna indicates that gyrocotylideans share some ultrastructural characters of the anterior organ with spathebothriidean cestodes with a single anterior attachment sucker-like organ. In contrast, the unique posterior rosette attachment organ with funnel-shaped canal of the Gyrocotylidea resembles the haptor of polyopisthocotylean monogeneans in its position at the posterior end of the body and presumed origin. The above-mentioned features add more clarity to support the basal position of the Gyrocotylidea Poche, 1926 among cestodes. In addition, they also indicate a possible relationship of gyrocotylidean ancestors with monogeneans.

Sponge grade body fossil with cellular resolution dating 60 Myr before the Cambrian

PubMed Central

Yin, Zongjun; Zhu, Maoyan; Davidson, Eric H.; Bottjer, David J.; Zhao, Fangchen; Tafforeau, Paul

2015-01-01

An extraordinarily well preserved, 600-million-year (Myr)-old, three-dimensionally phosphatized fossil displaying multiple independent characters of modern adult sponges has been analyzed by SEM and synchrotron X-ray tomography. The fossilized animal (Eocyathispongia qiania gen. et sp. nov.) is slightly more than 1.2 mm wide and 1.1 mm tall, is composed of hundreds of thousands of cells, and has a gross structure consisting of three adjacent hollow tubes sharing a common base. The main tube is crowned with a large open funnel, and the others end in osculum-like openings to the exterior. The external surface is densely covered with flat tile-like cells closely resembling sponge pinacocytes, and this layer is punctuated with smaller pores. A dense patch of external structures that display the form of a lawn of sponge papillae has also survived. Within the main funnel, an area where features of the inner surface are preserved displays a regular pattern of uniform pits. Many of them are surrounded individually by distinct collars, mounted in a supporting reticulum. The possibility cannot be excluded that these pits are the remains of a field of choanocytes. The character set evinced by this specimen, ranging from general anatomy to cell type, uniquely indicates that this specimen is a fossil of probable poriferan affinity. So far, we have only this single specimen, and although its organized and complex cellular structure precludes any reasonable interpretation that its origin is abiogenic, confirmation that it is indeed a fossilized sponge will clearly require discovery of additional specimens. PMID:25775601

The sensory features of a food cue influence its ability to act as an incentive stimulus and evoke dopamine release in the nucleus accumbens core

PubMed Central

Bryan, Myranda A.; Popov, Pavlo; Scarff, Raymond; Carter, Cody; Wright, Erin; Aragona, Brandon J.; Robinson, Terry E.

2016-01-01

The sensory properties of a reward-paired cue (a conditioned stimulus; CS) may impact the motivational value attributed to the cue, and in turn influence the form of the conditioned response (CR) that develops. A cue with multiple sensory qualities, such as a moving lever-CS, may activate numerous neural pathways that process auditory and visual information, resulting in CRs that vary both within and between individuals. For example, CRs include approach to the lever-CS itself (rats that “sign-track”; ST), approach to the location of reward delivery (rats that “goal-track”; GT), or an “intermediate” combination of these behaviors. We found that the multimodal sensory features of the lever-CS were important to the development and expression of sign-tracking. When the lever-CS was covered, and thus could only be heard moving, STs not only continued to approach the lever location but also started to approach the food cup during the CS period. While still predictive of reward, the auditory component of the lever-CS was a much weaker conditioned reinforcer than the visible lever-CS. This plasticity in behavioral responding observed in STs closely resembled behaviors normally seen in rats classified as “intermediates.” Furthermore, the ability of both the lever-CS and the reward-delivery to evoke dopamine release in the nucleus accumbens was also altered by covering the lever—dopamine signaling in STs resembled neurotransmission observed in rats that normally only GT. These data suggest that while the visible lever-CS was attractive, wanted, and had incentive value for STs, when presented in isolation, the auditory component of the cue was simply predictive of reward, lacking incentive salience. Therefore, the specific sensory features of cues may differentially contribute to responding and ensure behavioral flexibility. PMID:27918279

Injection of celiac disease patient sera or immunoglobulins to mice reproduces a condition mimicking early developing celiac disease.

PubMed

Kalliokoski, Suvi; Caja, Sergio; Frias, Rafael; Laurila, Kaija; Koskinen, Outi; Niemelä, Onni; Mäki, Markku; Kaukinen, Katri; Korponay-Szabó, Ilma R; Lindfors, Katri

2015-01-01

Typical features of celiac disease are small-bowel villus atrophy, crypt hyperplasia, and inflammation which develop gradually concomitant with ingestion of gluten. In addition, patients have anti-transglutaminase 2 (TG2) autoantibodies in their serum and tissues. The aim of this study was to establish whether celiac disease can be passively transferred to mice by serum or immunoglobulins. Serum aliquots or purified immunoglobulins (Ig) were intraperitoneally injected into Hsd:Athymic Nude-Foxn1nu mice for 8 or 27 days. As mice do not have proper IgA transport from peritoneum to blood, sera with a high content of IgG class anti-TG2 antibodies from untreated IgA-deficient celiac patients were used. Mouse sera were tested for celiac disease-specific autoantibodies, and several tissues were analyzed for autoantibody deposits targeted to TG2. Morphological assessment was made of the murine small intestinal mucosa. Injection of celiac disease patient sera or total IgG led to a significant delay in weight gain and mild diarrhea in a subset of mice. The mice injected with celiac patient sera or IgG had significantly decreased villus height crypt depth (Vh/CrD) ratios and celiac disease-specific autoantibody deposits targeted to TG2 in several tissues, including the small intestine. None of these features were observed in control mice. We conclude that administration of IgA-deficient celiac disease patient serum or total IgG induces both deterioration of the intestinal mucosa and clinical features of celiac disease in mice. The experimentally induced condition in the mice injected with patient serum or IgG resembles early developing celiac disease in humans. Celiac disease patient sera or total IgG was injected into athymic mice. A significant delay in weight gain and mild diarrhea was observed. Mice evinced significantly decreased villus height crypt depth ratios. Celiac disease-specific autoantibody deposits were present in several tissues. The condition in mice resembles early stage celiac disease in humans.

Ankle and hip postural strategies defined by joint torques

NASA Technical Reports Server (NTRS)

Runge, C. F.; Shupert, C. L.; Horak, F. B.; Zajac, F. E.; Peterson, B. W. (Principal Investigator)

1999-01-01

Previous studies have identified two discrete strategies for the control of posture in the sagittal plane based on EMG activations, body kinematics, and ground reaction forces. The ankle strategy was characterized by body sway resembling a single-segment-inverted pendulum and was elicited on flat support surfaces. In contrast, the hip strategy was characterized by body sway resembling a double-segment inverted pendulum divided at the hip and was elicited on short or compliant support surfaces. However, biomechanical optimization models have suggested that hip strategy should be observed in response to fast translations on a flat surface also, provided the feet are constrained to remain in contact with the floor and the knee is constrained to remain straight. The purpose of this study was to examine the experimental evidence for hip strategy in postural responses to backward translations of a flat support surface and to determine whether analyses of joint torques would provide evidence for two separate postural strategies. Normal subjects standing on a flat support surface were translated backward with a range of velocities from fast (55 cm/s) to slow (5 cm/s). EMG activations and joint kinematics showed pattern changes consistent with previous experimental descriptions of mixed hip and ankle strategy with increasing platform velocity. Joint torque analyses revealed the addition of a hip flexor torque to the ankle plantarflexor torque during fast translations. This finding indicates the addition of hip strategy to ankle strategy to produce a continuum of postural responses. Hip torque without accompanying ankle torque (pure hip strategy) was not observed. Although postural control strategies have previously been defined by how the body moves, we conclude that joint torques, which indicate how body movements are produced, are useful in defining postural control strategies. These results also illustrate how the biomechanics of the body can transform discrete control patterns into a continuum of postural corrections.

Feature Modeling of HfO2 Atomic Layer Deposition Using HfCl4/H2O

NASA Astrophysics Data System (ADS)

Stout, Phillip J.; Adams, Vance; Ventzek, Peter L. G.

2003-03-01

A Monte Carlo based feature scale model (Papaya) has been applied to atomic layer deposition (ALD) of HfO2 using HfCl_4/H_20. The model includes physical effects of transport to surface, specular and diffusive reflection within feature, adsorption, surface diffusion, deposition and etching. Discussed will be the 3D feature modeling of HfO2 deposition in assorted features (vias and trenches). The effect of feature aspect ratios, pulse times, cycle number, and temperature on film thickness, feature coverage, and film Cl fraction (surface/bulk) will be discussed. Differences between HfO2 ALD on blanket wafers and in features will be highlighted. For instance, the minimum pulse times sufficient for surface reaction saturation on blanket wafers needs to be increased when depositing on features. Also, HCl products created during the HfCl4 and H_20 pulses are more likely to react within a feature than at the field, reducing OH coverage within the feature (vs blanket wafer) thus limiting the maximum coverage attainable for a pulse over a feature.

Evidence for sulphur implantation in Europa's UV absorption band

NASA Technical Reports Server (NTRS)

Lane, A. L.; Nelson, R. M.; Matson, D. L.

1981-01-01

The UV spectral characteristics of the Galilean satellites are investigated (using data from the International Ultraviolet Explorer (IUE) spacecraft) as a function of the orbital position, large-scale areal variability, and temporal dynamics. The discovery of an absorption feature at 280 nm in Europa's reflection spectrum is reported and observations show that the absorption is strongest on the trailing hemisphere (central longitude 270 degrees). The feature resembles SO2 and seems to result from S-O bond formation between deeply implanted sulphur atoms and the adjacent damaged water-ice-lattice. The sulphur supposedly comes from energetic (hundreds of keV) sulphur ions that are present in the Jovian magnetosphere. An appropriate equilibrium condition can be found to match the observed spectral data if sputtering erosion occurs at no greater than approximately 20 meters per one billion years.

Detection of benign prostatic hyperplasia nodules in T2W MR images using fuzzy decision forest

NASA Astrophysics Data System (ADS)

Lay, Nathan; Freeman, Sabrina; Turkbey, Baris; Summers, Ronald M.

2016-03-01

Prostate cancer is the second leading cause of cancer-related death in men MRI has proven useful for detecting prostate cancer, and CAD may further improve detection. One source of false positives in prostate computer-aided diagnosis (CAD) is the presence of benign prostatic hyperplasia (BPH) nodules. These nodules have a distinct appearance with a pseudo-capsule on T2 weighted MR images but can also resemble cancerous lesions in other sequences such as the ADC or high B-value images. Describing their appearance with hand-crafted heuristics (features) that also exclude the appearance of cancerous lesions is challenging. This work develops a method based on fuzzy decision forests to automatically learn discriminative features for the purpose of BPH nodule detection in T2 weighted images for the purpose of improving prostate CAD systems.

Intracranial suprasellar angiolipoma: ultrastructural and immunohistochemical features.

PubMed

Lach, B; Lesiuk, H

1994-01-01

The authors present ultrastructural and immunohistochemical characteristics of an intracranial suprasellar tumor displaying features of cavernous angioma with islets of adipose tissue. Electron microscopy revealed thin-walled vessels separated by a loose collagenous stroma containing nests of mature adipocytes as well as fibroblasts, myofibroblasts, mast cells, and a few macrophages. Intracytoplasmic lipid droplets were also identified in scattered pericytes and smooth muscle cells of vascular walls and in the transitional cells resembling smooth muscle cells and adipocytes. Many adipose tissue cells were positive for S-100 protein with polyclonal antibodies. Other lipidized tumor cells were immunoreactive for some or all of the following: smooth muscle-specific actin, factor XIIIa, vimentin, and, occasionally, for desmin. Ultrastructure and immunohistochemistry indicate that in addition to typical adipocytes, lipidized cells of another nature contribute to the characteristic appearance of the adipose tissue component of angiolipoma.

Simian varicella virus reactivation in cynomolgus monkeys

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

Mahalingam, Ravi; Traina-Dorge, Vicki; Wellish, Mary

2007-11-10

SVV infection of primates closely resembles VZV infection of humans. Like VZV, SVV becomes latent in ganglionic neurons. We used this model to study the effect of immunosuppression on varicella reactivation. Cynomolgus monkeys latently infected with SVV were irradiated and treated with tacrolimus and prednisone. Of four latently infected monkeys that were immunosuppressed and subjected to the stress of transportation and isolation, one developed zoster, and three others developed features of subclinical reactivation. Another non-immunosuppressed latently infected monkey that was subjected to the same stress of travel and isolation showed features of subclinical reactivation. Virus reactivation was confirmed not onlymore » by the occurrence of zoster in one monkey, but also by the presence of late SVV RNA in ganglia, and the detection of SVV DNA in non-ganglionic tissue, and SVV antigens in skin, ganglia and lung.« less

High-Throughput Screening of Vascular Endothelium-Destructive or Protective Microenvironments: Cooperative Actions of Extracellular Matrix Composition, Stiffness, and Structure.

PubMed

Ding, Yonghui; Floren, Michael; Tan, Wei

2017-06-01

Pathological modification of the subendothelial extracellular matrix (ECM) has closely been associated with endothelial activation and subsequent cardiovascular disease progression. To understand regulatory mechanisms of these matrix modifications, the majority of previous efforts have focused on the modulation of either chemical composition or matrix stiffness on 2D smooth surfaces without simultaneously probing their cooperative effects on endothelium function on in vivo like 3D fibrous matrices. To this end, a high-throughput, combinatorial microarray platform on 2D and 3D hydrogel settings to resemble the compositions, stiffness, and structure of healthy and diseased subendothelial ECM has been established, and further their respective and combined effects on endothelial attachment, proliferation, inflammation, and junctional integrity have been investigated. For the first time, the results demonstrate that 3D fibrous structure resembling native ECM is a critical endothelium-protective microenvironmental factor by maintaining the stable, quiescent endothelium with strong resistance to proinflammatory stimuli. It is also revealed that matrix stiffening, in concert with chemical compositions resembling diseased ECM, particularly collagen III, could aggravate activation of nuclear factor kappa B, disruption of endothelium integrity, and susceptibility to proinflammatory stimuli. This study elucidates cooperative effects of various microenvironmental factors on endothelial activation and sheds light on new in vitro model for cardiovascular diseases. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Catatonic features in adolescents with schizophrenia with and without a comorbid pervasive developmental disorder

PubMed Central

2014-01-01

Background Catatonia has been associated with both schizophrenia and pervasive developmental disorders. The aim of this study was to evaluate catatonic features among adolescents suffering from schizophrenia. Further, we compared these features between adolescents with a comorbid pervasive developmental disorder and those without one. Finally, we wanted to compare the profile of catatonia-like features of our schizophrenia patients to that described earlier among persons with autism spectrum disorders. Methods The study comprised a consecutive sample of 18 adolescents with schizophrenia (mean age 15.6 years, SD 1.4) and their families. Diagnosis of schizophrenia was assessed with the Schedule for Affective Disorders and Schizophrenia for School-Aged Children – Present and Life-Time (K-SADS-PL) for the DSM-IV. The Diagnostic Interview for Social and Communication Disorders version 11 was used to assess catatonic features. Results All adolescents with schizophrenia had showed some lifetime catatonic features. Approximately 78% of them had already expressed these features before the age of 10. The number of catatonic features before the age of 10 was significantly higher among the adolescents with a comorbid pervasive developmental disorder compared to those without one. The numbers of catatonic features after the age of 10 did not significantly differ between the two groups. Over three-quarters of schizophrenia patients shared four lifetime catatonic features: “lacks facial expression”, “odd intonation”, “poor eye contact” and “lack of cooperation”. Conclusions Adolescent schizophrenia patients with a comorbid pervasive developmental disorder show many catatonic features in childhood whereas those without one seem to develop these features first in adolescence. Catatonic features exhibited by adolescents with schizophrenia resemble those described among persons with pervasive developmental disorders without schizophrenia. PMID:24914405

Catatonic features in adolescents with schizophrenia with and without a comorbid pervasive developmental disorder.

PubMed

Waris, Petra; Lindberg, Nina; Kettunen, Kirsi; Lipsanen, Jari; Tani, Pekka

2014-01-01

Catatonia has been associated with both schizophrenia and pervasive developmental disorders. The aim of this study was to evaluate catatonic features among adolescents suffering from schizophrenia. Further, we compared these features between adolescents with a comorbid pervasive developmental disorder and those without one. Finally, we wanted to compare the profile of catatonia-like features of our schizophrenia patients to that described earlier among persons with autism spectrum disorders. The study comprised a consecutive sample of 18 adolescents with schizophrenia (mean age 15.6 years, SD 1.4) and their families. Diagnosis of schizophrenia was assessed with the Schedule for Affective Disorders and Schizophrenia for School-Aged Children - Present and Life-Time (K-SADS-PL) for the DSM-IV. The Diagnostic Interview for Social and Communication Disorders version 11 was used to assess catatonic features. All adolescents with schizophrenia had showed some lifetime catatonic features. Approximately 78% of them had already expressed these features before the age of 10. The number of catatonic features before the age of 10 was significantly higher among the adolescents with a comorbid pervasive developmental disorder compared to those without one. The numbers of catatonic features after the age of 10 did not significantly differ between the two groups. Over three-quarters of schizophrenia patients shared four lifetime catatonic features: "lacks facial expression", "odd intonation", "poor eye contact" and "lack of cooperation". Adolescent schizophrenia patients with a comorbid pervasive developmental disorder show many catatonic features in childhood whereas those without one seem to develop these features first in adolescence. Catatonic features exhibited by adolescents with schizophrenia resemble those described among persons with pervasive developmental disorders without schizophrenia.

The Atmosphere and Climate of Venus

NASA Astrophysics Data System (ADS)

Bullock, M. A.; Grinspoon, D. H.

Venus lies just sunward of the inner edge of the Sun's habitable zone. Liquid water is not stable. Like Earth and Mars, Venus probably accreted at least an ocean's worth of water, although there are alternative scenarios. The loss of this water led to the massive, dry CO2 atmosphere, extensive H2SO4 clouds (at least some of the time), and an intense CO2 greenhouse effect. This chapter describes the current understanding of Venus' atmosphere, established from the data of dozens of spacecraft and atmospheric probe missions since 1962, and by telescopic observations since the nineteenth century. Theoretical work to model the temperature, chemistry, and circulation of Venus' atmosphere is largely based on analogous models developed in the Earth sciences. We discuss the data and modeling used to understand the temperature structure of the atmosphere, as well as its composition, cloud structure, and general circulation. We address what is known and theorized about the origin and early evolution of Venus' atmosphere. It is widely understood that Venus' dense CO2 atmosphere is the ultimate result of the loss of an ocean to space, but the timing of major transitions in Venus' climate is very poorly constrained by the available data. At present, the bright clouds allow only 20% of the sunlight to drive the energy balance and therefore determine conditions at Venus' surface. Like Earth and Mars, differential heating between the equator and poles drives the atmospheric circulation. Condensable species in the atmosphere create clouds and hazes that drive feedbacks that alter radiative forcing. Also in common with Earth and Mars, the loss of light, volatile elements to space produces long-term changes in composition and chemistry. As on Earth, geologic processes are most likely modifying the atmosphere and clouds by injecting gases from volcanos as well as directly through chemical reactions with the surface. The sensitivity of Venus' atmospheric energy balance is quantified in this chapter in terms of the initial forcing due to a perturbation, radiative response, and indirect responses, which are feedbacks — either positive or negative. When applied to one Venus climate model, we found that the albedo-radiative feedback is more important than greenhouse forcing for small changes in atmospheric H2O and SO2. An increase in these gases cools the planet by making the clouds brighter. On geologic timescales the reaction of some atmospheric species (SO2, CO, OCS, S, H2O, H2S, HCl, HF) with surface minerals could cause significant changes in atmospheric composition. Laboratory data and thermochemical modeling have been important for showing that atmospheric SO2 would be depleted in ~10 m.y. if carbonates are available at the surface. Without replenishment, the clouds would disappear. Alternatively, the oxidation of pyrite could add SO2 to the atmosphere while producing stable Fe oxides at the surface. The correlation of near-infrared high emissivity (dark) surface features with three young, large volcanos on Venus is strong evidence for recent volcanic activity at these sites, certainly over the timescale necessary to support the clouds. We address the nature of heterogeneous reactions with the surface and the implications for climate change on Venus. Chemical and mineralogical signatures of past climates must exist at the surface and below, so in situ experiments on the composition of surface layers are vital for reconstructing Venus' past climate. Many of the most Earth-like planets found around other stars will probably resemble Venus or a younger version of Venus. We finish the chapter with discussing what Venus can tell us about life in the universe, since it is an example of a planetary climate rendered uninhabitable. It also resembles our world's likely future. As with the climate history of Venus, however, the timing of predictable climate transitions on the Earth is poorly constrained by the data.

Rapid generation of mitochondrial superoxide induces mitochondrion-dependent but caspase-independent cell death in hippocampal neuronal cells that morphologically resembles necroptosis☆

PubMed Central

Fukui, Masayuki; Choi, Hye Joung; Zhu, Bao Ting

2013-01-01

Studies in recent years have revealed that excess mitochondrial superoxide production is an important etiological factor in neurodegenerative diseases, resulting from oxidative modifications of cellular lipids, proteins, and nucleic acids. Hence, it is important to understand the mechanism by which mitochondrial oxidative stress causes neuronal death. In this study, the immortalized mouse hippocampal neuronal cells (HT22) in culture were used as a model and they were exposed to menadione (also known as vitamin K3) to increase intracellular superoxide production. We found that menadione causes preferential accumulation of superoxide in the mitochondria of these cells, along with the rapid development of mitochondrial dysfunction and cellular ATP depletion. Neuronal death induced by menadione is independent of the activation of the MAPK signaling pathways and caspases. The lack of caspase activation is due to the rapid depletion of cellular ATP. It was observed that two ATP-independent mitochondrial nucleases, namely, AIF and Endo G, are released following menadione exposure. Silencing of their expression using specific siRNAs results in transient suppression (for ~12 h) of mitochondrial superoxide-induced neuronal death. While suppression of the mitochondrial superoxide dismutase expression markedly sensitizes neuronal cells to mitochondrial superoxide-induced cytotoxicity, its over-expression confers strong protection. Collectively, these findings showed that many of the observed features associated with mitochondrial superoxide-induced cell death, including caspase independency, rapid depletion of ATP level, mitochondrial release of AIF and Endo G, and mitochondrial swelling, are distinctly different from those of apoptosis; instead they resemble some of the known features of necroptosis. PMID:22575170

Analysis of gene expression in a developmental context emphasizes distinct biological leitmotifs in human cancers

PubMed Central

Naxerova, Kamila; Bult, Carol J; Peaston, Anne; Fancher, Karen; Knowles, Barbara B; Kasif, Simon; Kohane, Isaac S

2008-01-01

Background In recent years, the molecular underpinnings of the long-observed resemblance between neoplastic and immature tissue have begun to emerge. Genome-wide transcriptional profiling has revealed similar gene expression signatures in several tumor types and early developmental stages of their tissue of origin. However, it remains unclear whether such a relationship is a universal feature of malignancy, whether heterogeneities exist in the developmental component of different tumor types and to which degree the resemblance between cancer and development is a tissue-specific phenomenon. Results We defined a developmental landscape by summarizing the main features of ten developmental time courses and projected gene expression from a variety of human tumor types onto this landscape. This comparison demonstrates a clear imprint of developmental gene expression in a wide range of tumors and with respect to different, even non-cognate developmental backgrounds. Our analysis reveals three classes of cancers with developmentally distinct transcriptional patterns. We characterize the biological processes dominating these classes and validate the class distinction with respect to a new time series of murine embryonic lung development. Finally, we identify a set of genes that are upregulated in most cancers and we show that this signature is active in early development. Conclusion This systematic and quantitative overview of the relationship between the neoplastic and developmental transcriptome spanning dozens of tissues provides a reliable outline of global trends in cancer gene expression, reveals potentially clinically relevant differences in the gene expression of different cancer types and represents a reference framework for interpretation of smaller-scale functional studies. PMID:18611264

Bacterially induced precipitation of CaCO 3: An example from studies of cyanobacterial mats. Final report

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

Chafetz, Henry S.

1990-04-30

Bacteria induce the precipitation of calcium carbonate in the laboratory and in nature by altering their chemical environment. Geologists are recognizing the possibility that bacterially induced precipitates may form significant mineral deposits, unfortunately, there are currently no sound criteria by which they can be recognized in recent sediments, or in the rock record. Cultures of aerobic and facultative bacteria from cyanobacterial mats on Andros Island, Bahamas, and Baffin Bay, Texas, induced the precipitation of calcium carbonate under controlled conditions. Crusts, the largest features formed, are composed of 5--200μm diameter bundles which are, in turn, composed of numerous individual crystals. Themore » smallest observed features are 0.1--0.4μm spheres and rods which comprise some individual crystals and crystal bundles. Crystal bundles resembling rhombohedra, tetragonal disphenoids, tetragonal dipyramids, and calcite dumbbells appear to be uniquely bacterial in origin, and they have all been observed in recent sediments. Swollen rods, discs, curved dumbbells, and 50--200μm optically continuous crystals resembling brushes may be uniquely bacterial in origin, however, they have not been reported by other laboratories nor observed in natural settings. Presence of any of these forms in recent sediments should be taken as strong evidence for bacterial influence. Spheres and aragonite dumbbells have also been observed in natural environments, however, they are not always bacterial in origin. Precipitation of calcium carbonate occurs preferentially on dead cyanobacteria in the presence of bacteria. Lithification of algal mats to form stromatolites may take place in the zone of decaying organic matter due to bacterial activity.« less

Bacterially induced precipitation of CaCO sub 3 : An example from studies of cyanobacterial mats

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

Chafetz, H.S.

1990-04-30

Bacteria induce the precipitation of calcium carbonate in the laboratory and in nature by altering their chemical environment. Geologists are recognizing the possibility that bacterially induced precipitates may form significant mineral deposits, unfortunately, there are currently no sound criteria by which they can be recognized in recent sediments, or in the rock record. Cultures of aerobic and facultative bacteria from cyanobacterial mats on Andros Island, Bahamas, and Baffin Bay, Texas, induced the precipitation of calcium carbonate under controlled conditions. Crusts, the largest features formed, are composed of 5--200{mu}m diameter bundles which are, in turn, composed of numerous individual crystals. Themore » smallest observed features are 0.1--0.4{mu}m spheres and rods which comprise some individual crystals and crystal bundles. Crystal bundles resembling rhombohedra, tetragonal disphenoids, tetragonal dipyramids, and calcite dumbbells appear to be uniquely bacterial in origin, and they have all been observed in recent sediments. Swollen rods, discs, curved dumbbells, and 50--200{mu}m optically continuous crystals resembling brushes may be uniquely bacterial in origin, however, they have not been reported by other laboratories nor observed in natural settings. Presence of any of these forms in recent sediments should be taken as strong evidence for bacterial influence. Spheres and aragonite dumbbells have also been observed in natural environments, however, they are not always bacterial in origin. Precipitation of calcium carbonate occurs preferentially on dead cyanobacteria in the presence of bacteria. Lithification of algal mats to form stromatolites may take place in the zone of decaying organic matter due to bacterial activity.« less

Europa and Callisto under the watchful gaze of Jupiter

NASA Technical Reports Server (NTRS)

2000-01-01

One moment in an ancient, orbital dance is caught in this color picture taken by NASA's Cassini spacecraft on Dec. 7, 2000, just as two of Jupiter's four major moons, Europa and Callisto, were nearly perfectly aligned with each other and the center of the planet.

The distances are deceiving. Europa, seen against Jupiter, is 600,000 kilometers (370,000 miles) above the planet's cloud tops. Callisto, at lower left, is nearly three times that distance from the cloud tops. Europa is a bit smaller than Earth's Moon and has one of the brightest surfaces in the solar system. Callisto is 50 percent bigger -- roughly the size of Saturn's largest satellite, Titan -- and three times darker than Europa. Its brightness had to be enhanced in this picture, relative Europa's and Jupiter's, in order for Callisto to be seen in this image.

Europa and Callisto have had very different geologic histories but share some surprising similarities, such as surfaces rich in ice. Callisto has apparently not undergone major internal compositional stratification, but Europa's interior has differentiated into a rocky core and an outer layer of nearly pure ice. Callisto's ancient surface is completely covered by large impact craters: The brightest features seen on Callisto in this image were discovered by the Voyager spacecraft in 1979 to be bright craters, like those on our Moon. In contrast, Europa's young surface is covered by a wild tapestry of ridges, chaotic terrain and only a handful of large craters.

Recent data from the magnetometer carried by the Galileo spacecraft, which has been in orbit around Jupiter since 1995, indicate the presence of conducting fluid, most likely salty water, inside both worlds.

Scientists are eager to discover whether the surface of Saturn's Titan resembles that of Callisto or Europa, or whether it is entirely different when Cassini finally reaches its destination in 2004.

Cassini is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini mission for NASA's Office of Space Science, Washington, D.C.

Relating sub-surface ice features to physiological stress in a climate sensitive mammal, the American pika (Ochotona princeps).

PubMed

Wilkening, Jennifer L; Ray, Chris; Varner, Johanna

2015-01-01

The American pika (Ochotona princeps) is considered a sentinel species for detecting ecological effects of climate change. Pikas are declining within a large portion of their range, and ongoing research suggests loss of sub-surface ice as a mechanism. However, no studies have demonstrated physiological responses of pikas to sub-surface ice features. Here we present the first analysis of physiological stress in pikas living in and adjacent to habitats underlain by ice. Fresh fecal samples were collected non-invasively from two adjacent sites in the Rocky Mountains (one with sub-surface ice and one without) and analyzed for glucocorticoid metabolites (GCM). We also measured sub-surface microclimates in each habitat. Results indicate lower GCM concentration in sites with sub-surface ice, suggesting that pikas are less stressed in favorable microclimates resulting from sub-surface ice features. GCM response was well predicted by habitat characteristics associated with sub-surface ice features, such as lower mean summer temperatures. These results suggest that pikas inhabiting areas without sub-surface ice features are experiencing higher levels of physiological stress and may be more susceptible to changing climates. Although post-deposition environmental effects can confound analyses based on fecal GCM, we found no evidence for such effects in this study. Sub-surface ice features are key to water cycling and storage and will likely represent an increasingly important component of water resources in a warming climate. Fecal samples collected from additional watersheds as part of current pika monitoring programs could be used to further characterize relationships between pika stress and sub-surface ice features.

Transient Slope Lineae Formation in a Well-Preserved Crater

NASA Image and Video Library

2017-11-20

This enhanced color image from NASA's Mars Reconnaissance Orbiter (MRO) shows what are called "recurring slope lineae"s in Tivat Crater. The narrow, dark flows descend downhill (towards the upper left). Analysis shows that the flows all end at approximately the same slope, which is similar to the angle of repose for sand. RSL are mostly found on steep rocky slopes in dark regions of Mars, such as the southern mid-latitudes, Valles Marineris near the equator, and in Acidalia Planitia on the northern plains. The appearance and growth of these features resemble seeping liquid water, but how they form remains unclear, and this research demonstrated that the RSL flows seen by HiRISE are likely moving granular material like sand and dust. These findings indicate that present-day Mars may not have a significant volume of liquid water. The water-restricted conditions that exist on Mars would make it difficult for Earth-like life to exist near the surface of the planet. The map is projected here at a scale of 25 centimeters (9.8 inches) per pixel. [The original image scale is 25.6 centimeters (10.8 inches) per pixel (with 1 x 1 binning); objects on the order of 77 centimeters (30.3 inches) across are resolved.] North is up. https://photojournal.jpl.nasa.gov/catalog/PIA22114

Micro- and nanostructures of iridescent wing scales in purple emperor butterflies (Lepidoptera: Apatura ilia and A. iris).

PubMed

Ćurčić, Srećko B; Pantelić, Dejan V; Ćurčić, Božidar P M; Savić-Šević, Svetlana N; Makarov, Slobodan E; Lačković, Vesna B; Labudović-Borović, Milica M; Ćurčić, Nina B; Stojanović, Dejan V

2012-07-01

Apatura ilia (Denis and Schiffermüller, 1775) and A. iris (Linnaeus, 1758) are fascinating butterflies found in the Palaearctic ecozone (excepting the north of Africa). The wings of these insects are covered with a great number of two types of scales positioned like roof tiles. Type I scales are on the surface, while type II scales are situated below them. The structural color of the type I scales is recognized only on the dorsal side of both the fore and hind wings of the males of the aforementioned species. Both types of scales are responsible for pigment color of the wings, but iridescence is observed only in the type I scales. The brilliant structural color is due to a multilayer structure. The features of the scales, their dimensions and fine structure were obtained using scanning electron microscopy. Cross sections of the scales were then analyzed by transmission electron microscopy. The scales of the "normal" and clytie forms of A. ilia have a different nanostructure, but are of the same type. A similar type of structure, but with a different morphology, was also noticed in A. iris. The scales of the analyzed species resemble the scales of tropical Morpho butterflies. Copyright © 2012 Wiley Periodicals, Inc.

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

Goldman, Allen M.

The goal of this program was to study new physical phenomena that might be relevant to the performance of conductive devices and circuits of the smallest realizable feature sizes possible using physical rather than biological techniques. Although the initial scientific work supported involved the use of scanning tunneling microscopy and spectroscopy to ascertain the statistics of the energy level distribution of randomly sized and randomly shaped quantum dots, or nano-crystals, the main focus was on the investigation of selected properties, including superconductivity, of conducting and superconducting nanowires prepared using electron-beam-lithography. We discovered a magnetic-field-restoration of superconductivity in out-of-equilibrium nanowires drivenmore » resistive by current. This phenomenon was explained by the existence of a state in which dissipation coexisted with nonvanishing superconducting order. We also produced ultra-small superconducting loops to study a predicted anomalous fluxoid quantization, but instead, found a magnetic-field-dependent, high-resistance state, rather than superconductivity. Finally, we developed a simple and controllable nanowire in an induced charged layer near the surface of a masked single-crystal insulator, SrTiO 3. The layer was induced using an electric double layer transistor employing an ionic liquid (IL). The transport properties of the induced nanowire resembled those of collective electronic transport through an array of quantum dots.« less

Tethys Eyes Saturn

NASA Image and Video Library

2015-06-15

The two large craters on Tethys, near the line where day fades to night, almost resemble two giant eyes observing Saturn. The location of these craters on Tethys' terminator throws their topography into sharp relief. Both are large craters, but the larger and southernmost of the two shows a more complex structure. The angle of the lighting highlights a central peak in this crater. Central peaks are the result of the surface reacting to the violent post-impact excavation of the crater. The northern crater does not show a similar feature. Possibly the impact was too small to form a central peak, or the composition of the material in the immediate vicinity couldn't support the formation of a central peak. In this image Tethys is significantly closer to the camera, while the planet is in the background. Yet the moon is still utterly dwarfed by the giant Saturn. This view looks toward the anti-Saturn side of Tethys. North on Tethys is up and rotated 42 degrees to the right. The image was taken in visible light with the Cassini spacecraft wide-angle camera on April 11, 2015. The view was obtained at a distance of approximately 75,000 miles (120,000 kilometers) from Tethys. Image scale at Tethys is 4 miles (7 kilometers) per pixel. http://photojournal.jpl.nasa.gov/catalog/pia18318

Breaking Ice: Fracture Processes in Floating Ice on Earth and Elsewhere

NASA Astrophysics Data System (ADS)

Scambos, T. A.

2016-12-01

Rapid, intense fracturing events in the ice shelves of the Antarctic Peninsula reveal a set of processes that were not fully appreciated prior to the series of ice shelf break-ups observed in the late 1990s and early 2000s. A series of studies have uncovered a fascinating array of relationships between climate, ocean, and ice: intense widespread hydrofracture; repetitive hydrofracture induced by ice plate bending; the ability for sub-surface flooded firn to support hydrofracture; potential triggering by long-period wave action; accelerated fracturing by trapped tsunamic waves; iceberg disintegration, and a remarkable ice rebound process from lake drainage that resembles runaway nuclear fission. The events and subsequent studies have shown that rapid regional warming in ice shelf areas leads to catastrophic changes in a previously stable ice mass. More typical fracturing of thick ice plates is a natural consequence of ice flow in a complex geographic setting, i.e., it is induced by shear and divergence of spreading plate flow around obstacles. While these are not a result of climate or ocean change, weather and ocean processes may impact the exact timing of final separation of an iceberg from a shelf. Taking these terrestrial perspectives to other ice-covered ocean worlds, cautiously, provides an observational framework for interpreting features on Europa and Enceladus.