327 research outputs found
-minimal surface and manifold with positive -Bakry-\'{E}mery Ricci curvature
In this paper, we first prove a compactness theorem for the space of closed
embedded -minimal surfaces of fixed topology in a closed three-manifold with
positive Bakry-\'{E}mery Ricci curvature. Then we give a Lichnerowicz type
lower bound of the first eigenvalue of the -Laplacian on compact manifold
with positive -Bakry-\'{E}mery Ricci curvature, and prove that the lower
bound is achieved only if the manifold is isometric to the -shpere, or the
-dimensional hemisphere. Finally, for compact manifold with positive
-Bakry-\'{E}mery Ricci curvature and -mean convex boundary, we prove an
upper bound for the distance function to the boundary, and the upper bound is
achieved if only if the manifold is isometric to an Euclidean ball.Comment: 15 page
Transport spectroscopy in a time-modulated open quantum dot
We have investigated the time-modulated coherent quantum transport phenomena
in a ballistic open quantum dot. The conductance and the electron dwell
time in the dots are calculated by a time-dependent mode-matching method. Under
high-frequency modulation, the traversing electrons are found to exhibit three
types of resonant scatterings. They are intersideband scatterings: into
quasibound states in the dots, into true bound states in the dots, and into
quasibound states just beneath the subband threshold in the leads. Dip
structures or fano structures in are their signatures. Our results show
structures due to 2 intersideband processes. At the above
scattering resonances, we have estimated, according to our dwell time
calculation, the number of round-trip scatterings that the traversing electrons
undertake between the two dot openings.Comment: 8 pages, 5 figure
Cooperative binding of ETS2 and NFAT link Erk1/2 and calcineurin signaling in the pathogenesis of cardiac hypertrophy
BACKGROUND: Cardiac hypertrophy is an independent risk factor for heart failure, a leading cause of morbidity and mortality globally. The calcineurin/NFAT (nuclear factor of activated T cells) pathway and the MAPK/Erk (extracellular signal-regulated kinase) pathway contribute to the pathogenesis of cardiac hypertrophy as an inter-dependent network of signaling cascades. However, how these pathways interact remains unclear, and specifically few direct targets responsible for the pro-hypertrophic role of NFAT have been described. METHODS: By engineering a cardiomyocyte-specific ETS2 (a member of E26 transformationspecific sequence (ETS)-domain family) knockout mice, we investigated the role of ETS2 in cardiac hypertrophy. Primary cardiomyocytes were also used to evaluate ETS2 function in cell growth. RESULTS: ETS2 is phosphorylated and activated by Erk1/2 upon hypertrophic stimulation in both mouse (n = 3) and human heart samples (n = 8-19). Conditional deletion of ETS2 in mouse cardiomyocytes protects against pressure overload-induced cardiac hypertrophy (n = 6-11). Furthermore, silencing of ETS2 in the hearts of calcineurin transgenic mice significantly attenuates hypertrophic growth and contractile dysfunction (n = 8). As a transcription factor, ETS2 is capable of binding to the promoters of hypertrophic marker genes, such as ANP, BNP and Rcan1.4 (n = 4). Additionally, we report that ETS2 forms a complex with NFAT to stimulate transcriptional activity through increased NFAT binding to the promoters of at least two hypertrophy-stimulated genes, Rcan1.4 and miR-223 (n = 4-6). Suppression of miR-223 in cardiomyocytes inhibits calcineurin-mediated cardiac hypertrophy (n = 6), revealing miR-223 as a novel pro-hypertrophic target of the calcineurin-NFAT and Erk1/2-ETS2 pathways. CONCLUSIONS: In aggregate, our findings point to a critical role for ETS2 in calcineurin-NFAT pathway-driven cardiac hypertrophy and unveil a previously unknown molecular connection between the Erk1/2 activation of ETS2 and expression of NFAT/ETS2 target genes
Assessment and improvement of the Plasmodium yoelii yoelii genome annotation through comparative analysis
Motivation: The sequencing of the Plasmodium yoelii genome, a model rodent malaria parasite, has greatly facilitated research for the development of new drug and vaccine candidates against malaria. Unfortunately, only preliminary gene models were annotated on the partially sequenced genome, mostly by in silico gene prediction, and there has been no major improvement of the annotation since 2002
Using confirmatory factor analysis to evaluate construct validity of the Brief Pain Inventory (BPI)
Context: The Brief Pain Inventory (BPI) is a frequently used instrument designed to assess the patient-reported outcome of pain. The majority of factor analytic studies have found a two-factor (i.e., pain intensity and pain interference) structure for this instrument; however, because the BPI was developed with an a priori hypothesis of the relationship among its items, it follows that construct validity investigations should use confirmatory factor analysis (CFA). Objectives: The purpose of this work was to establish the construct validity of the BPI using a CFA framework and demonstrate factorial invariance using a range of demographic variables. Methods: A retrospective CFA was completed in a sample of individuals diagnosed with HIV/AIDS and cancer (n = 364; 63% male; age 21-92 years, M = 51.80). A baseline one-factor model was compared against two-factor and three-factor models (i.e., pain intensity, activity interference, and affective interference) that were developed based on the hypothetical design of the instrument. Results: Fit indices for the three-factor model were statistically superior when compared with the one-factor model and marginally better when compared with the two-factor model. This three-factor structure was found to be invariant across disease, age, and ethnicity groups. Conclusion: The results of this study provide evidence to support a three-factor representation of the BPI, and the originally hypothesized two-factor structure. Such findings will begin to provide clinical trialists, pharmaceutical sponsors, and regulators with confidence in the psychometric properties of this instrument when considering its inclusion in clinical research
Static Anisotropic Solutions in f(T) Theory
In a previously work, we undertook a static and anisotropic content in
theory and obtained new spherically symmetric solutions considering a constant
torsion and some particular conditions for the pressure. In this paper, still
in the framework of theory, new spherically symmetric solutions are
obtained, first considering the general case of an isotropic fluid and later
the anisotropic content case in which the generalized conditions for the matter
content are considered such that the energy density, the radial and tangential
pressures depend on the algebraic and its derivative .
Moreover, we obtain the algebraic function through the reconstruction
method for two cases and also study a polytropic model for the stellar
structure.Comment: 23 pages, Published in Euro. Phys. J.
Prunella vulgaris: A comprehensive review of chemical constituents, pharmacological effects and clinical applications.
Prunella vulgaris (PV) is a perennial herb belonging to the Labiate family and is widely distributed in northeastern Asian countries such as Korea, Japan, and China. It is reported to display diverse biological activities including anti-microbial, anti-cancer, and anti-inflammation as determined by in vitro or in vivo studies. So far, about 200 compounds have been isolated from PV plant and majority of these have been characterized mainly as triterpenoids, sterols and flavonoids, followed by coumarins, phenylpropanoids, polysaccharides and volatile oils. This review summarizes and analyzes the current knowledge on the chemical constituents, pharmacological activities, mechanisms of action and clinical applications of the PV plant including its potential as a future medicinal plant. Although some of the chemical constituents of the PV plant and their mechanism of action have been investigated the biological activities of many of these remain unknown and further clinical trials are required to further enhance its reputation as a medicinal plant
An overview of the taxonomy, phylogeny, and typification of nectriaceous fungi in Cosmospora, Acremonium, Fusarium, Stilbella, and Volutella
A comprehensive phylogenetic reassessment of the ascomycete genus
Cosmospora (Hypocreales, Nectriaceae) is undertaken using
fresh isolates and historical strains, sequences of two protein encoding
genes, the second largest subunit of RNA polymerase II (rpb2), and a
new phylogenetic marker, the larger subunit of ATP citrate lyase
(acl1). The result is an extensive revision of taxonomic concepts,
typification, and nomenclatural details of many anamorph- and
teleomorph-typified genera of the Nectriaceae, most notably
Cosmospora and Fusarium. The combined phylogenetic analysis
shows that the present concept of Fusarium is not monophyletic and
that the genus divides into two large groups, one basal in the family, the
other terminal, separated by a large group of species classified in genera
such as Calonectria, Neonectria, and Volutella. All accepted
genera received high statistical support in the phylogenetic analyses.
Preliminary polythetic morphological descriptions are presented for each
genus, providing details of perithecia, micro- and/or macro-conidial
synanamorphs, cultural characters, and ecological traits. Eight species are
included in our restricted concept of Cosmospora, two of which have
previously documented teleomorphs and all of which have
Acremonium-like microconidial anamorphs. A key is provided to the
three anamorphic species recognised in Atractium, which is removed
from synonymy with Fusarium and epitypified for two macroconidial
synnematous species and one sporodochial species associated with waterlogged
wood. Dialonectria is recognised as distinct from Cosmospora
and two species with teleomorph, macroconidia and microconidia are accepted,
including the new species D. ullevolea. Seven species, one with a
known teleomorph, are classified in Fusicolla, formerly considered a
synonym of Fusarium including members of the F. aquaeductuum
and F. merismoides species complex, with several former varieties
raised to species rank. Originally a section of Nectria,
Macroconia is raised to generic rank for five species, all producing
a teleomorph and macroconidial anamorph. A new species of the
Verticillium-like anamorphic genus Mariannaea is described
as M. samuelsii. Microcera is recognised as distinct from
Fusarium and a key is included for four macroconidial species, that
are usually parasites of scale insects, two of them with teleomorphs. The four
accepted species of Stylonectria each produce a teleomorph and micro-
and macroconidial synanamorphs. The Volutella species sampled fall
into three clades. Pseudonectria is accepted for a perithecial and
sporodochial species that occurs on Buxus. Volutella s. str.
also includes perithecial and/or sporodochial species and is revised to
include a synnematous species formerly included in Stilbella. The
third Volutella-like clade remains unnamed. All fungi in this paper
are named using a single name system that gives priority to the oldest generic
names and species epithets, irrespective of whether they are originally based
on anamorph or teleomorph structures. The rationale behind this is
discussed
Grain refinement of magnesium alloys: a review of recent research, theoretical developments and their application
This paper builds on the ‘‘Grain Refinement of Mg Alloys’’ published in 2005 and reviews the grain refinement research onMg alloys that has been undertaken since then with an emphasis on the theoretical and analytical methods that have been developed. Consideration of recent research results and current theoretical knowledge has highlighted two important factors that affect an alloy’s as-cast grain size. The first factor applies to commercial Mg-Al alloys where it is concluded that impurity and minor elements such as Fe and Mn have a substantially negative impact on grain size because, in combination with Al, intermetallic phases can be formed that tend to poison the more potent native or deliberately added nucleant particles present in the melt. This factor appears to explain the contradictory experimental outcomes reported in the literature and suggests that the search for a more potent and reliable grain refining technology may need to take a different approach. The second factor applies to all alloys and is related to the role of constitutional supercooling which, on the one hand, promotes grain nucleation and, on the other hand, forms a nucleation-free zone preventing further nucleation within this zone, consequently limiting the grain refinement achievable, particularly in low solute-containing alloys. Strategies to reduce the negative impact of these two factors are discussed. Further, the Interdependence model has been shown to apply to a broad range of casting methods from slow cooling gravity die casting to fast cooling high pressure die casting and dynamic methods such as ultrasonic treatment
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