736 research outputs found
Some Cohomotopy Groups of Suspended Projective Planes
In this paper we compute some cohomotopy groups of the
suspended complex and quaternionic projective plane by use of the exact sequence associated with the canonical cofiber sequence and a formula about a multiple of the identity class of the suspended projective plane.</p
Overexpression of the Synthetic Chimeric Native-T-Phylloplanin-GFP Genes Optimized for Monocot and Dicot Plants Renders Enhanced Resistance to Blue Mold Disease in Tobacco (\u3cem\u3eN. Tabacum L.\u3c/em\u3e)
To enhance the natural plant resistance and to evaluate the antimicrobial properties of phylloplanin against blue mold, we have expressed a synthetic chimeric native-phylloplanin-GFP protein fusion in transgenic Nicotiana tabacum cv. KY14, a cultivar that is highly susceptible to infection by Peronospora tabacina. The coding sequence of the tobacco phylloplanin gene along with its native signal peptide was fused with GFP at the carboxy terminus. The synthetic chimeric gene (native-phylloplanin-GFP) was placed between the modified Mirabilis mosaic virus full-length transcript promoter with duplicated enhancer domains and the terminator sequence from the rbcSE9 gene. The chimeric gene, expressed in transgenic tobacco, was stably inherited in successive plant generations as shown by molecular characterization, GFP quantification, and confocal fluorescent microscopy. Transgenic plants were morphologically similar to wild-type plants and showed no deleterious effects due to transgene expression. Blue mold-sensitivity assays of tobacco lines were performed by applying P. tabacina sporangia to the upper leaf surface. Transgenic lines expressing the fused synthetic native-phyllopanin-GFP gene in the leaf apoplast showed resistance to infection. Our results demonstrate that in vivo expression of a synthetic fused native-phylloplanin-GFP gene in plants can potentially achieve natural protection against microbial plant pathogens, including P. tabacina in tobacco
Candidates for asteroid dust trails
The contribution of different sources to the circumsolar dust cloud (known as the zodiacal cloud) can be deduced from diagnostic observations. We used the Spitzer Space Telescope to observe the diffuse thermal emission of the zodiacal cloud near the ecliptic. Several structures were identified in these observations, including previously known asteroid dust bands, which are thought to have been produced by recent asteroid collisions, and cometary trails. Interestingly, two of the detected dust trails, denoted t1 and t2 here, cannot be linked to any known comet. Trails t1 and t2 represent a much larger integrated brightness than all known cometary trails combined and may therefore be major contributors to the circumsolar dust cloud. We used our Spitzer observations to determine the orbits of these trails and were able to link them to two ("orphan" or type II) trails that were discovered by the Infrared Astronomical Satellite (IRAS) in 1983. The orbits of trails t1 and t2 that we determined by combining the Spitzer and IRAS data have semimajor axes, eccentricities, and inclinations like those of the main-belt asteroids. We therefore propose that trails t1 and t2 were produced by very recent (<~100 kyr old) collisional breakups of small, <~10 km diameter main-belt asteroids
Analysis of mechanism of sand deposition inside a fishing port using BG model
A large amount of sand deposited in the wave-shelter zone of Ohtsu fishing port located in northern Ibaraki Prefecture, Japan, resulting in a difficulty in navigation at the pot entrance. The BG model (a three-dimensional model for predicting beach changes based on Bagnold's concept) ws used to solve this problem. Measures against sand deposition inside the port were investigated and the most appropriate measure found for preventing sand deposition was the extension of a jetty by 100 m at the tip of the west breakwater. The applicability of the BG model to such prediction was confirmed
Time Series Study of Rhino Habitat and its Impact on Rhino Population in Gorumara National Park through Remote Sensing Technology
Gorumara National Park located within the flood plains of Jaldhaka and Murty river in the Dooars area of Northern West Bengal has a mosaic of natural vegetation consisting of tall grasslands, woodlands, tropical semi-evergreen forests and tropical moist deciduous forests, part of which get inundated in recurring floods. The Greater Indian One Horned Rhinoceros which is the flagship specie of this National Park has positively responded to the regular Wild Life Habitat Management regime introduced since 1995 showing trends of steady increase in its population as the habitat manipulation resulted in the increase of the Rhino habitat. This review tries to establish the Rhino population dynamics vis a vis increase in Rhino habitat using Remote sensing technology over the years since the area comes under purview of Protected Area network management
Decay Properties of Bh and Db Produced in the Cm + Na Reaction
Decay properties of an isotope Bh and its daughter nucleus Db
produced by the Cm(Na, 5\textit{n}) reaction were studied by
using a gas-filled recoil separator coupled with a position-sensitive
semiconductor detector. Bh was clearly identified from the correlation
of the known nuclide, Db. The obtained decay properties of Bh
and Db are consistent with those observed in the 113 chain,
which provided further confirmation of the discovery of 113.Comment: Accepted for publication in J. Phys. Soc. JPN., to be published in
Vol.78 No.
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The FAD Cofactor of RebC Shifts to an IN Conformation upon Flavin Reduction†,‡
RebC is a putative flavin hydroxylase functioning together with RebP to carry out a key step in the biosynthesis of rebeccamycin. To probe the mechanism of flavin-based chemistry in RebC, we solved the structure of RebC with reduced flavin. Upon flavin reduction, the RebC crystal undergoes a change in its unit cell dimension concurrent with a 5 Å movement of the isoalloxazine ring, positioning the flavin ring adjacent to the substrate-binding pocket. Additionally, a disordered helix becomes ordered upon flavin reduction, closing off one side of the substrate-binding pocket. This structure, along with previously reported structures, increases our understanding of the RebC enzyme mechanism, indicating that either the reduction of the flavin itself or binding of substrate is sufficient to drive major conformational changes in RebC to generate a closed active site. Our finding that flavin reduction seals the active site such that substrate cannot enter suggests that our reduced flavin RebC structure is off-pathway and that substrate binding is likely to precede flavin reduction during catalysis. Along with kinetic data presented here, these structures suggest that the first cycle of catalysis in RebC may resemble that of p-hydroxybenzoate hydroxylase, with substrate binding promoting flavin reduction
On the existence and structure of a mush at the inner core boundary of the Earth
It has been suggested about 20 years ago that the liquid close to the inner
core boundary (ICB) is supercooled and that a sizable mushy layer has developed
during the growth of the inner core. The morphological instability of the
liquid-solid interface which usually results in the formation of a mushy zone
has been intensively studied in metallurgy, but the freezing of the inner core
occurs in very unusual conditions: the growth rate is very small, and the
pressure gradient has a key role, the newly formed solid being hotter than the
adjacent liquid. We investigate the linear stability of a solidification front
under such conditions, pointing out the destabilizing role of the thermal and
solutal fields, and the stabilizing role of the pressure gradient. The main
consequence of the very small solidification rate is the importance of
advective transport of solute in liquid, which tends to remove light solute
from the vicinity of the ICB and to suppress supercooling, thus acting against
the destabilization of the solidification front. For plausible phase diagrams
of the core mixture, we nevertheless found that the ICB is likely to be
morphologically unstable, and that a mushy zone might have developed at the
ICB. The thermodynamic thickness of the resulting mushy zone can be
significant, from km to the entire inner core radius, depending on
the phase diagram of the core mixture. However, such a thick mushy zone is
predicted to collapse under its own weight, on a much smaller length scale
( km). We estimate that the interdendritic spacing is probably
smaller than a few tens of meter, and possibly only a few meters
A simple, low-cost conductive composite material for 3D printing of electronic sensors
3D printing technology can produce complex objects directly from computer aided digital designs. The technology has traditionally been used by large companies to produce fit and form concept prototypes (‘rapid prototyping’) before production. In recent years however there has been a move to adopt the technology as full-scale manufacturing solution. The advent of low-cost, desktop 3D printers such as the RepRap and Fab@Home has meant a wider user base are now able to have access to desktop manufacturing platforms enabling them to produce highly customised products for personal use and sale. This uptake in usage has been coupled with a demand for printing technology and materials able to print functional elements such as electronic sensors. Here we present formulation of a simple conductive thermoplastic composite we term ‘carbomorph’ and demonstrate how it can be used in an unmodified low-cost 3D printer to print electronic sensors able to sense mechanical flexing and capacitance changes. We show how this capability can be used to produce custom sensing devices and user interface devices along with printed objects with embedded sensing capability. This advance in low-cost 3D printing with offer a new paradigm in the 3D printing field with printed sensors and electronics embedded inside 3D printed objects in a single build process without requiring complex or expensive materials incorporating additives such as carbon nanotubes
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