3,420 research outputs found
A statistical model to describe invariants extracted from a 3-D quadric surface patch and its applications in region-based recognition
A statistical model, describing noise-disturbed invariants extracted from a surface patch of a range image, has been developed and applied to region based pose estimation and classification of 3D quadrics. The Mahalanobis distance, which yields the same results as a Baysian classifier, is used for the classification of the surface patches. The results, compared with the Euclidean distance, appear to be much more reliabl
Developmental waves of mechanosensitivity acquisition in sensory neuron subtypes during embryonic development
Somatic sensation relies on the transduction of physical stimuli into electrical signals by sensory neurons of the dorsal root ganglia. Little is known about how and when during development different types of sensory neurons acquire transduction competence. We directly investigated the emergence of electrical excitability and mechanosensitivity of embryonic and postnatal mouse sensory neurons. We show that sensory neurons acquire mechanotransduction competence coincident with peripheral target innervation. Mechanotransduction competence arises in different sensory lineages in waves, coordinated by distinct developmental mechanisms. Sensory neurons that are mechanoreceptors or proprioceptors acquire mature mechanotransduction indistinguishable from the adult already at E13. This process is independent of neurotrophin-3 and may be driven by a genetic program. In contrast, most nociceptive (pain sensing) sensory neurons acquire mechanosensitive competence as a result of exposure to target-derived nerve growth factor. The highly regulated process of mechanosensory acquisition unveiled here, reveals new strategies to identify molecules required for sensory neuron mechanotransduction
Strongly walk-regular graphs
We study a generalization of strongly regular graphs. We call a graph
strongly walk-regular if there is an such that the number of walks of
length from a vertex to another vertex depends only on whether the two
vertices are the same, adjacent, or not adjacent. We will show that a strongly
walk-regular graph must be an empty graph, a complete graph, a strongly regular
graph, a disjoint union of complete bipartite graphs of the same size and
isolated vertices, or a regular graph with four eigenvalues. Graphs from the
first three families in this list are indeed strongly -walk-regular for
all , whereas the graphs from the fourth family are -walk-regular
for every odd . The case of regular graphs with four eigenvalues is the
most interesting (and complicated) one. Such graphs cannot be strongly
-walk-regular for even . We will characterize the case that regular
four-eigenvalue graphs are strongly -walk-regular for every odd ,
in terms of the eigenvalues. There are several examples of infinite families of
such graphs. We will show that every other regular four-eigenvalue graph can be
strongly -walk-regular for at most one . There are several examples
of infinite families of such graphs that are strongly 3-walk-regular. It
however remains open whether there are any graphs that are strongly
-walk-regular for only one particular different from 3
Electrospun medicated shellac nanofibers for colon-targeted drug delivery
Medicated shellac nanofibers providing colon-specific sustained release were fabricated using coaxial electrospinning. A solution of 7.5 g shellac and 1.5 g of ferulic acid (FA) in 10 mL ethanol was used as the core fluid, and a mixture of ethanol and N,N-dimethylformamide (8/10 v/v) as the shell. The presence of the shell fluid was required to prevent frequent clogging of the spinneret. The diameters of the fibers (D) can be manipulated by varying the ratio of shell to core flow rates (F), according to the equation D = 0.52Fâ0.19. Scanning electron microscopy images revealed that fibers prepared with F values of 0.1 and 0.25 had linear morphologies with smooth surfaces, but when the shell fluid flow rate was increased to 0.5 the fiber integrity was compromised. FA was found to be amorphously distributed in the fibers on the basis of X-ray diffraction and differential scanning calorimetry results. This can be attributed to good compatibility between the drug and carrier: IR spectra indicated the presence of hydrogen bonds between the two. In vitro dissolution tests demonstrated that there was minimal FA release at pH 2.0, and sustained release in a neutral dissolution medium. The latter occurred through an erosion mechanism. During the dissolution processes, the shellac fibers were gradually converted into nanoparticles as the FA was freed into solution, and ultimately completely dissolved
The productions of the top-pions and top-Higgs associated with the charm quark at the hadron colliders
In the topcolor-assistant technicolor (TC2) model, the typical physical
particles, top-pions and top-Higgs, are predicted and the existence of these
particles could be regarded as the robust evidence of the model. These
particles are accessible at the Tevatron and LHC, and furthermore the
flavor-changing(FC) feature of the TC2 model can provide us a unique chance to
probe them. In this paper, we study some interesting FC production processes of
top-pions and top-Higgs at the Tevatron and LHC, i.e., and
productions. We find that the light charged top-pions
are not favorable by the Tevatron experiments and the Tevatron has a little
capability to probe neutral top-pion and top-Higgs via these FC production
processes. At the LHC, however, the cross section can reach the level of
pb for production and fb for
production. So one can expect that enough signals could be
produced at the LHC experiments. Furthermore, the SM background should be clean
due to the FC feature of the processes and the FC decay modes can provide us the typical signal to
detect the top-pions and top-Higgs. Therefore, it is hopeful to find the signal
of top-pions and top-Higgs with the running of the LHC via these FC processes.Comment: 12 pages, 6 figure
Comparison of Volatile Compounds in Two Brandies Using HS-SPME Coupled with GC-O, GC-MS and Sensory Evaluation
The aim of this study was to compare the volatile compounds between Changyu XO and Hennessy XO. Sensoryevaluation was performed by a panel of tasters. Qualitative and semi-quantitative analysis was achieved byheadspace solid phase micro-extraction (HS-SPME), coupled with gas chromatography-mass spectrometry (GCMS)and gas chromatography-olfactometry (GC-O). A total of 160 volatile compounds were identified in the twobrands of brandy. Of these, 118 compounds were common to both Changyu XO and Hennessy XO; 18 compoundswere specific to Changyu XO and 24 were specific to Hennessy XO. A total of 85 aroma compounds responsiblefor brandy flavour were identified by GC-O, of which 68 were common to both brands, while seven and tenwere specific to Changyu XO and Hennessy XO, respectively. The study provided detailed information aboutthe compounds responsible for the characteristic flavour of specific brandies. According to statistical analysis,significant differences were recorded between Changyu XO and Hennessy XO. Most volatile compounds inChangyu XO occurred at lower concentrations than those in Hennessy XO. Based on sensory evaluation analysis,the floral, alcohol and rancid aroma descriptors achieved higher scores in Changyu XO and Hennessy XO, whilethe lime aroma seemed specific to Hennessy XO. Herb and almond aromas were specific to Changyu XO
Nanofibers fabricated using triaxial electrospinning as zero order drug delivery systems
A new strategy for creating functional trilayer nanofibers through triaxial electrospinning is demonstrated. Ethyl cellulose (EC) was used as the filament-forming matrix in the outer, middle, and inner working solutions and was combined with varied contents of the model active ingredient ketoprofen (KET) in the three fluids. Triaxial electrospinning was successfully carried out to generate medicated nanofibers. The resultant nanofibers had diameters of 0.74 ± 0.06 Όm, linear morphologies, smooth surfaces, and clear trilayer nanostructures. The KET concentration in each layer gradually increased from the outer to the inner layer. In vitro dissolution tests demonstrated that the nanofibers could provide linear release of KET over 20 h. The protocol reported in this study thus provides a facile approach to creating functional nanofibers with sophisticated structural features
The flavor-changing bottom-strange quark production in the littlest Higgs model with T parity at the ILC
In the littlest Higgs model with T-parity (LHT) the mirror quarks induce the
special flavor structures and some new flavor-changing (FC) couplings which
could greatly enhance the production rates of the FC processes. We in this
paper study some bottom and anti-strange production processes in the LHT model
at the International Linear Collider (ILC), i.e.,
and . The results show that the production
rates of these processes are sizeable for the favorable values of the
parameters. Therefore, it is quite possible to test the LHT model or make some
constrains on the relevant parameters of the LHT through the detection of these
processes at the ILC.Comment: 12 pages, 8 figure
Medicated Janus fibers fabricated using a Teflon-coated side-by-side spinneret
A family of medicated Janus fibers that provides highly tunable biphasic drug release was fabricated using a side-by-side electrospinning process employing a Teflon-coated parallel spinneret. The coated spinneret facilitated the formation of a Janus Taylor cone and in turn high quality integrated Janus structures, which could not be reliably obtained without the Teflon coating. The fibers prepared had one side consisting of polyvinylpyrrolidone (PVP) K60 and ketoprofen, and the other of ethyl cellulose (EC) and ketoprofen. To modulate and tune drug release, PVP K10 was doped into the EC side in some cases. The fibers were linear and had flat morphologies with an indent in the center. They provide biphasic drug release, with the PVP K60 side dissolving very rapidly to deliver a loading dose of the active ingredient, and the EC side resulting in sustained release of the remaining ketoprofen. The addition of PVP K10 to the EC side was able to accelerate the second stage of release; variation in the dopant amount permitted the release rate and extent this phase to be precisely tuned. These results offer the potential to rationally design systems with highly controllable drug release profiles, which can complement natural biological rhythms and deliver maximum therapeutic effects
The rare decays B --> K(*) anti-K(*) and R-parity violating supersymmetry
We study the branching ratios, the direct CP asymmetries in decays and the polarization fractions of decays by employing the QCD factorization in the minimal
supersymmetric standard model with R-parity violation. We derive the new upper
bounds on the relevant R-parity violating couplings from the latest
experimental data of , and some of these constraints
are stronger than the existing bounds. Using the constrained parameter spaces,
we predict the R-parity violating effects on the other quantities in decays which have not been measured yet. We find that the
R-parity violating effects on the branching ratios and the direct
asymmetries could be large, nevertheless their effects on the longitudinal
polarizations of decays are small. Near future
experiments can test these predictions and shrink the parameter spaces.Comment: 31 pages with 10 figure
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