30,344 research outputs found
Proximity and anomalous field-effect characteristics in double-wall carbon nanotubes
Proximity effect on field-effect characteristic (FEC) in double-wall carbon
nanotubes (DWCNTs) is investigated. In a semiconductor-metal (S-M) DWCNT, the
penetration of electron wavefunctions in the metallic shell to the
semiconducting shell turns the original semiconducting tube into a metal with a
non-zero local density of states at the Fermi level. By using a two-band
tight-binding model on a ladder of two legs, it is demonstrated that anomalous
FEC observed in so-called S-M type DWCNTs can be fully understood by the
proximity effect of metallic phases.Comment: 4 pages, 4 figure
An Invariance Principle of G-Brownian Motion for the Law of the Iterated Logarithm under G-expectation
The classical law of the iterated logarithm (LIL for short)as fundamental
limit theorems in probability theory play an important role in the development
of probability theory and its applications. Strassen (1964) extended LIL to
large classes of functional random variables, it is well known as the
invariance principle for LIL which provide an extremely powerful tool in
probability and statistical inference. But recently many phenomena show that
the linearity of probability is a limit for applications, for example in
finance, statistics. As while a nonlinear expectation--- G-expectation has
attracted extensive attentions of mathematicians and economists, more and more
people began to study the nature of the G-expectation space. A natural question
is: Can the classical invariance principle for LIL be generalized under
G-expectation space? This paper gives a positive answer. We present the
invariance principle of G-Brownian motion for the law of the iterated logarithm
under G-expectation
Strong laws of large numbers for sub-linear expectations
We investigate three kinds of strong laws of large numbers for capacities
with a new notion of independently and identically distributed (IID) random
variables for sub-linear expectations initiated by Peng. It turns out that
these theorems are natural and fairly neat extensions of the classical
Kolmogorov's strong law of large numbers to the case where probability measures
are no longer additive. An important feature of these strong laws of large
numbers is to provide a frequentist perspective on capacities.Comment: 10 page
Effect of Corynoline Isolated from Corydalis bungeana Turcz on Lipopolysaccharides-Induced Sepsis In vivo and In vitro
Purpose: To investigate the protective effect of corynoline isolated from Corydalis bungeana Turcz on lipopolysaccharides (LPS)-induced sepsis, and determine the possible mechanism of anti-sepsis effect of the isolated corynoline.Methods: Corynoline was extracted by column chromatography. LPS (100 ng/mL) was used to induce the release of TNF-α and IL-6 in RAW 264.7 cells, and the isolated corynoline was added. ELISA method was used to determine the levels of TNF-α and IL- 6. Furthermore, sepsis in mice was established by injection of LPS (2 mg/kg, i.v.), and the levels of TNF- α and IL-6 in plasma were determined by ELISA method. For survival rate test, LPS (15 mg/kg, i.v.) and heat-killed E. coli (1.0 ~1011 CFU/kg, i.v.) were used to establish sepsis in mice model, and the mice were observed in 7 days.Results: The results indicate that corynoline significantly elevated the survival rate of septic mice induced by LPS and heat-killed E. coli, in a dose-dependent manner (p < 0.05). Corynoline decreased the release of TNF-α and IL-6 induced by LPS, in a dose-dependent manner (p < 0.05).Conclusion: Treatment with corynoline significantly inhibits the mortality of LPS-induced septic mice, and the mechanism of action is probably related to the decrease of TNF-α and IL-6 release. Thus corynoline has the potential to be developed as an effective and safe drug for treating sepsis.Keywords: Corynoline, Corydalis bungeana, Sepsis, Lipopolysaccharides, TNF-α, IL-
Molecular characterization and expression analysis of chalcone synthase gene during flower development in tree peony (Paeonia suffruticosa)
Chalcone synthase (CHS, EC: 2.3.1.74) is a key enzyme in the flavonoid and anthocyanin biosynthesis pathway. In order to investigate the role of CHS in tree peony flower coloration mechanism, we isolated and characterized the CHS gene from Paeonia suffruticosa cv. Yu Ji Yan Zhuang and analyzed its spatial and temporal expression patterns during floral development. The cDNA sequence of the CHS gene in P. suffruticosa (Ps-CHS1, genbank accession no. GQ483511) was 1475 bp in full length containing an opening reading frame (ORF) of 1185 bp that encoded a 394 amino acid polypeptide. Bioinformatic analysis showed that, Ps-CHS1 possessed all the conserved active sites for the CHS function as well as the family signature. Sequence alignment and phylogenetic analysis revealed that Ps-CHS1 shared high homology with CHS from plants in Salicaceae, Malvaceae and Rosaceae. The homology-based structural modeling showed that Ps-CHS1 had the typical structure of CHS. Southern blot analysis indicated that CHS was encoded by a small multigene family in the genome of tree peony. Anthocyanidin content in full-opening flower petals accumulated to the highest level. Real-time polymerase chain reaction amplification (PCR) analysis indicated that, Ps-CHS1 showed the highest transcript abundance in petals, moderate levels in sepals, low levels in leaves and stamens, and the lowest levels in carpels. Ps-CHS1 was actively expressed during flower development and increased gradually until reached maximal expression when flower fully opened. These results indicated that Ps- CHS1 was involved in the flower pigmentation of tree peony.Key words: Tree peony (Paeonia suffruticosa), chalcone synthase, expression, anthocyanin
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Fine-Scale Variations in Eucritic Pyroxene FeO/MnO: Process vs. Provenance.
Most asteroidal igneous rocks are eucrite-like basalts and gabbros, composed mostly of ferroan low- and high-Ca pyroxenes and calcic plagioclase, plus smaller amounts of silica (most commonly tridymite), ilmenite, chromite, troilite, Ca-phosphate, metal and sometimes ferroan olivine. Eucrite-like mafic rocks are fragments of the crusts of differentiated asteroids, and most are likely from 4 Vesta
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