3,438 research outputs found
Phase transitions in a gas of anyons
We continue our numerical Monte Carlo simulation of a gas of closed loops on
a 3 dimensional lattice, however now in the presence of a topological term
added to the action corresponding to the total linking number between the
loops. We compute the linking number using certain notions from knot theory.
Adding the topological term converts the particles into anyons. Using the
correspondence that the model is an effective theory that describes the
2+1-dimensional Abelian Higgs model in the asymptotic strong coupling regime,
the topological linking number simply corresponds to the addition to the action
of the Chern-Simons term. We find the following new results. The system
continues to exhibit a phase transition as a function of the anyon mass as it
becomes small \cite{mnp}, although the phases do not change the manifestation
of the symmetry. The Chern-Simons term has no effect on the Wilson loop, but it
does affect the {\rm '}t Hooft loop. For a given configuration it adds the
linking number of the 't Hooft loop with all of the dynamical vortex loops to
the action. We find that both the Wilson loop and the 't Hooft loop exhibit a
perimeter law even though there are no massless particles in the theory, which
is unexpected.Comment: 6 pages, 5 figure
Experimental Overlay of Glazon over Two Bridge Decks
In accordance with a Personal Service Agreement entered into with the Glazon Industries, Inc., on July 2, 1971, the two subject decks were patched and overlayed with Glazon. On July 27, 1971, work started on RP 106-286-HG3, KY 395 bridge over I 64 in Shelby County. Work consisted of routing old concrete and sandblasting the surface (Figures 1 and 2). State personnel and equipment were used for all cleaning operations. The same procedures were followed to clean HM 99-1324A-MB3 in Powell County near Clay City.
On July 28, 1971, Glazon personnel and equipment arrived at the work site in Shelby County. Glazon representatives judged the cleaning adequate and proceeded with patching the southbound lane (Figure 3). No accurate information is available as to the exact formulation of the Glazon used or proportions in the mix. Glazon Industries declined disclosure of such information since their material was not patented. Before patching, the holes were thoroughly dried. Shrinkage and cracking were noticed in the patches shortly after drying (Figure 4). Later, on other lanes, patch holes were primed with a Glazon liquid before patching (Figures 5 and 6).
After a short drying period, the deck was sprayed with a Glazon mix similar to that for patching but more fluid (Figures 7 and 8). Some problems were encountered due to weak air supply, but were shortly overcome. The sprayed deck looked satisfactory to Glazon personnel who did most of the work in patching and overlaying the deck. The operation was moved to the Clay City bridge and the same procedures were followed in working the northbound lane.
Two wingwalls on the Shelby County bridge were sprayed with a Glazon mix made with white cement.
On August 3, 1971, both bridges were completed though work was interrupted by rain several times. On August 5, 1971, both bridges were reopened to two-lane traffic.
This Division closely observed these operations from the beginning. It was later learned from the Division of Maintenance that the northbound lane of the Shelby County deck, which was badly deteriorating, had been repaired on September 15, 1971
Evaluation of canonical siRNA and Dicer substrate RNA for inhibition of hepatitis C virus genome replication - a comparative study
Hepatitis C virus (HCV) frequently establishes persistent infections in the liver, leading to the development of chronic hepatitis and, potentially, to liver cirrhosis and hepatocellular carcinoma at later stages. The objective of this study was to test the ability of five Dicer substrate siRNAs (DsiRNA) to inhibit HCV replication and to compare these molecules to canonical 21 nt siRNA. DsiRNA molecules were designed to target five distinct regions of the HCV genome - the 5′ UTR and the coding regions for NS3, NS4B, NS5A or NS5B. These molecules were transfected into Huh7.5 cells that stably harboured an HCV subgenomic replicon expressing a firefly luciferase/neoR reporter (SGR-Feo-JFH-1) and were also tested on HCVcc-infected cells. All of the DsiRNAs inhibited HCV replication in both the subgenomic system and HCVcc-infected cells. When DsiRNAs were transfected prior to infection with HCVcc, the inhibition levels reached 99.5%. When directly compared, canonical siRNA and DsiRNA exhibited similar potency of virus inhibition. Furthermore, both types of molecules exhibited similar dynamics of inhibition and frequencies of resistant mutants after 21 days of treatment. Thus, DsiRNA molecules are as potent as 21 nt siRNAs for the inhibition of HCV replication and may provide future approaches for HCV therapy if the emergence of resistant mutants can be addressed
Structure of the caffeine-pyrogallol complex:revisiting a pioneering structural analysis of a model pharmaceutical cocrystal
The 1967 attempt of structural analysis of the solid-state complex of caffeine and pyrogallol was a pioneering structural investigation in the supramolecular chemistry of caffeine, of what today would easily be considered an archetype of a model pharmaceutical cocrystal. Re-investigating this historically important system demonstrates that this long overlooked complex is most likely a tetrahydrate with a different structure and composition than initially proposed, and provides the crystal structure of the anhydrous cocrystal.</p
Properties Study of ZnS Thin Films Prepared by Spray Pyrolysis Method
Zinc sulfide (ZnS) is important II-VI semiconductors material for the development of various modern
technologies and photovoltaic applications. ZnS thin film was prepared by using chemical spray pyrolysis
technique. The starting solution is a mixture of 0.1 M zinc chloride as source of Zn and 0.05 M thiourea as
source of S. The glass substrate temperature was varied in the range of 300 °C-400 °C to investigate the influence of substrate temperature on the structure, chemical composition, morphological and optical properties of ZnS films. The DRX analyses indicated that ZnS films have polycrystalline cubic structure with
(111) preferential orientation and grain size varied from 25 to 60 nm, increasing with substrate temperature.
The optical properties of these films have been studied in the wavelength range 300-2500 nm using
UV-VIS spectro-photometer. The ZnS films has a band gap of 3.89 eV-3.96 eV
Properties Study of ZnS Thin Films Prepared by Spray Pyrolysis Method
Zinc sulfide (ZnS) is important II-VI semiconductors material for the development of various modern
technologies and photovoltaic applications. ZnS thin film was prepared by using chemical spray pyrolysis
technique. The starting solution is a mixture of 0.1 M zinc chloride as source of Zn and 0.05 M thiourea as
source of S. The glass substrate temperature was varied in the range of 300 °C-400 °C to investigate the influence of substrate temperature on the structure, chemical composition, morphological and optical properties of ZnS films. The DRX analyses indicated that ZnS films have polycrystalline cubic structure with
(111) preferential orientation and grain size varied from 25 to 60 nm, increasing with substrate temperature.
The optical properties of these films have been studied in the wavelength range 300-2500 nm using
UV-VIS spectro-photometer. The ZnS films has a band gap of 3.89 eV-3.96 eV
organic crystals: superconducting versus antiferromagnetic instabilities in an anisotropic triangular lattice Hubbard model
A Hubbard model at half-filling on an anisotropic triangular lattice has been
proposed as the minimal model to describe conducting layers of
organic materials. The model interpolates between the
square lattice and decoupled chains. The materials
present many similarities with cuprates, such as the presence of unconventional
metallic properties and the close proximity of superconducting and
antiferromagnetic phases. As in the cuprates, spin fluctuations are expected to
play a crucial role in the onset of superconductivity. We perform a
weak-coupling renormalization-group analysis to show that a superconducting
instability occurs. Frustration in the antiferromagnetic couplings, which
arises from the underlying geometrical arrangement of the lattice, breaks the
perfect nesting of the square lattice at half-filling. The spin-wave
instability is suppressed and a superconducting instability predominates. For
the isotropic triangular lattice, there are again signs of long-range magnetic
order, in agreement with studies at strong-coupling.Comment: 4 pages, 5 eps figs, to appear in Can. J. Phys. (proceedings of the
Highly Frustrated Magnetism (HFM-2000) conference, Waterloo, Canada, June
2000
Regulation of Spo12 Phosphorylation and Its Essential Role in the FEAR Network
Background:
In budding yeast, the protein phosphatase Cdc14 coordinates late mitotic events and triggers exit from mitosis. During early anaphase, Cdc14 is activated by the FEAR network, but how signaling through the FEAR network occurs is poorly understood.
Results:
We find that the FEAR network component Spo12 is phosphorylated on S118. This phosphorylation is essential for Spo12 function and is restricted to early anaphase, when the FEAR network is active. The anaphase-specific phosphorylation of Spo12 requires mitotic CDKs and depends on the FEAR network components Separase and Slk19. Furthermore, we find that CDC14 is required to maintain Spo12 in the dephosphorylated state prior to anaphase.
Conclusions:
Our results show that anaphase-specific phosphorylation of Spo12 is essential for FEAR network function and raise the interesting possibility that Cdc14 itself helps to prevent the FEAR network from being prematurely activated.National Institutes of Health (U.S.) (grant GM 056800)Howard Hughes Medical Institute (Investigator
Characterization of Thermally Oxidized Ti6Al4V Alloys for Dental Application
In this work, thermal oxidation processes in the temperature range of 500-800 °C in air for 4 hours
were performed on Ti6Al4V medical grade alloys to modify their surface structure and morphology for
better wear and corrosion resistance, osseointegration and biocompatibility. Different type and amount of
nanostructured phases were obtained as revealed by the X-ray diffration (XRD) technique such as:
alumina, anatase and rutile. X’pert high score plus software was used for the calculation of the percentage
and crystallite sizes of these phases. Alumina phase exhibits the greater amount of the oxide layers when
Ti6Al4V alloys annealed at 500 °C, while rutile was found to be the predominant phase at 800 °C
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