Universal role of correlation entropy in critical phenomena

In statistical physics, if we successively divide an equilibrium system into two parts, we will face a situation that, within a certain length $\xi$, the physics of a subsystem is no longer the same as the original system. Then the extensive properties of the thermal entropy $S($AB$)= S($A$)+S($B$)$ is violated. This observation motivates us to introduce the concept of correlation entropy between two points, as measured by mutual information in the information theory, to study the critical phenomena. A rigorous relation is established to display some drastic features of the non-vanishing correlation entropy of the subsystem formed by any two distant particles with long-range correlation. This relation actually indicates the universal role of the correlation entropy in understanding critical phenomena. We also verify these analytical studies in terms of two well-studied models for both the thermal and quantum phase transitions: two-dimensional Ising model and one-dimensional transverse field Ising model. Therefore, the correlation entropy provides us with a new physical intuition in critical phenomena from the point of view of the information theory.Comment: 10 pages, 9 figure

Transplantation of Human Undifferentiated Embryonic Stem Cells into A Myocardial Infarction Rat Model

Human embryonic stem (hES) cells hold great therapeutic potential for cell transplantation. To date, it remains uncertain whether undifferentiated hES cells can differentiate into cardiac lineage in vivo during myocardial infarction. Here we provide the first report that undifferentiated hES cells can survive in rat hearts during myocardial infarction without the formation of teratoma using undifferentiated green fluorescent protein (GFP)-transgenic hES cells. Using a laser-capture microscope to dissect the GFP-positive cell area from the hES-injected hearts, we documented the expression of human cardiac-specific genes, including GATA-4, Nkx-2.5, and cardiac troponin I. Taken together, our results demonstrate that undifferentiated hES cells can be driven to the cardiac lineage under the local injured environment in the heart, which may provide a potential method for regenerating de novo myocardium to treat myocardial infarction.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/63274/1/scd.2006.110206.pd

The production of the new gauge boson BHB_{H} via e−γe^{-}\gamma collision in the littlest Higgs model

The new lightest gauge boson $B_H$ with mass of a few hundred GeV is predicted in the littlest Higgs model. $B_H$ should be accessible in the planed ILC and the observation of such particle can strongly support the littlest Higgs model. The realization of $\gamma\gamma$ and $e\gamma$ collision will open a wider window to probe $B_H$. In this paper, we study the new gauge boson $B_{H}$ production processes $e^{-}\gamma\to e^{-}\gamma B_{H}$ and $e^{-}\gamma\to e^{-}Z B_{H}$ at the ILC. Our results show that the production cross section of the process $e^{-}\gamma\to e^{-}Z B_{H}$ is less than one fb in the most parameter spaces while the production cross section of the process $e^{-}\gamma\to e^{-}\gamma B_{H}$ can reach the level of tens fb and even hundreds of fb in the sizable parameter spaces allowed by the electroweak precision data. With the high luminosity, the sufficient typical signals could be produced, specially via $e^{-}\gamma\to e^{-}\gamma B_{H}$. Because the final electron and photon beams can be easily identified and the signal can be easily distinguished from the background produced by $Z$ and $H$ decaying, $B_H$ should be detectable via $e\gamma$ collision at the ILC. Therefore, the processes $e^{-}\gamma\to e^{-}\gamma B_{H}$ and $e^{-}\gamma\to e^{-}Z B_{H}$ provide a useful way to detect $B_{H}$ and test the littlest Higgs model.Comment: 15 pages, 3 figures. Some typos have been corrected, we have added some new references, and there are also some changes in equation 1

A duplex real-time RT-PCR assay for detecting H5N1 avian influenza virus and pandemic H1N1 influenza virus

A duplex real-time reverse transcriptase polymerase chain reaction (RT-PCR) assay was improved for simultaneous detection of highly pathogenic H5N1 avian influenza virus and pandemic H1N1 (2009) influenza virus, which is suitable for early diagnosis of influenza-like patients and for epidemiological surveillance. The sensitivity of this duplex real-time RT-PCR assay was 0.02 TCID50 (50% tissue culture infective dose) for H5N1 and 0.2 TCID50 for the pandemic H1N1, which was the same as that of each single-target RT-PCR for pandemic H1N1 and even more sensitive for H5N1 with the same primers and probes. No cross reactivity of detecting other subtype influenza viruses or respiratory tract viruses was observed. Two hundred and thirty-six clinical specimens were tested by comparing with single real-time RT-PCR and result from the duplex assay was 100% consistent with the results of single real-time RT-PCR and sequence analysis

Determinant and Weyl anomaly of Dirac operator: a holographic derivation

We present a holographic formula relating functional determinants: the fermion determinant in the one-loop effective action of bulk spinors in an asymptotically locally AdS background, and the determinant of the two-point function of the dual operator at the conformal boundary. The formula originates from AdS/CFT heuristics that map a quantum contribution in the bulk partition function to a subleading large-N contribution in the boundary partition function. We use this holographic picture to address questions in spectral theory and conformal geometry. As an instance, we compute the type-A Weyl anomaly and the determinant of the iterated Dirac operator on round spheres, express the latter in terms of Barnes' multiple gamma function and gain insight into a conjecture by B\"ar and Schopka.Comment: 11 pages; new comments and references added, typos correcte

Realizing the Heteromorphic Superlattice: Repeated Heterolayers of Amorphous Insulator and Polycrystalline Semiconductor with Minimal Interface Defects

An Unconventional Heteromorphic Superlattice (HSL) is Realized, Comprised of Repeated Layers of Different Materials with Differing Morphologies: Semiconducting Pc-In2O3 Layers Interleaved with Insulating A-MoO3 Layers. Originally Proposed by Tsu in 1989, Yet Never Fully Realized, the High Quality of the HSL Heterostructure Demonstrated Here Validates the Intuition of Tsu, Whereby the Flexibility of the Bond Angle in the Amorphous Phase and the Passivation Effect of the Oxide at Interfacial Bonds Serve to Create Smooth, High-Mobility Interfaces. the Alternating Amorphous Layers Prevent Strain Accumulation in the Polycrystalline Layers While Suppressing Defect Propagation Across the HSL. for the HSL with 7:7 Nm Layer Thickness, the Observed Electron Mobility of 71 Cm2 Vs-1, Matches that of the Highest Quality In2O3 Thin Films. the Atomic Structure and Electronic Properties of Crystalline In2O3/amorphous MoO3 Interfaces Are Verified using Ab-Initio Molecular Dynamics Simulations and Hybrid Functional Calculations. This Work Generalizes the Superlattice Concept to an Entirely New Paradigm of Morphological Combinations

Probing the lightest new gauge boson BHB_H in the littlest Higgs model via the processes γγ→ffˉBH\gamma\gamma \to f\bar{f}B_H at the ILC

The neutral gauge boson $B_H$ with the mass of hundreds GeV, is the lightest particle predicted by the littlest Higgs(LH) model, and such particle should be the first signal of the LH model at the planed ILC if it exists indeed. In this paper, we study some processes of the $B_H$ production associated with the fermion pair at the ILC, i.e., $\gamma\gamma\to f\bar{f}B_{H}$. The studies show that the most promising processes to detect $B_H$ among $\gamma\gamma\to f\bar{f}B_{H}$ are $\gamma\gamma\to l'^+l'^-B_{H}(l'=e,\mu)$, and they can produce the sufficient signals in most parameter space preferred by the electroweak precision data at the ILC. On the other hand, the signal produced via the certain $B_H$ decay modes is typical and such signal can be easily identified from the SM background. Therefore, $B_H$, the lightest gauge boson in the LH model would be detectable at the photon collider realized at the ILC.Comment: 12 pages, 4 figure

The Rare Codon AGA Is Involved in Regulation of Pyoluteorin Biosynthesis in Pseudomonas protegens Pf-5

The soil bacterium Pseudomonas protegens Pf-5 can colonize root and seed surfaces of many plants, protecting them from infection by plant pathogenic fungi and oomycetes. The capacity to suppress disease is attributed to Pf-5's production of a large spectrum of antibiotics, which is controlled by complex regulatory circuits operating at the transcriptional and post-transcriptional levels. In this study, we analyzed the genomic sequence of Pf-5 for codon usage patterns and observed that the six rarest codons in the genome are present in all seven known antibiotic biosynthesis gene clusters. In particular, there is an abundance of rare codons in pltR, which encodes a member of the LysR transcriptional regulator family that controls the expression of pyoluteorin biosynthetic genes. To test the hypothesis that rare codons in pltR influence pyoluteorin production, we generated a derivative of Pf-5 in which 23 types of rare codons in pltR were substituted with synonymous preferred codons. The resultant mutant produced pyoluteorin at levels 15 times higher than that of the wild-type Pf-5. Accordingly, the promoter activity of the pyoluteorin biosynthetic gene pltL was 20 times higher in the codon-modified stain than in the wild-type. pltR has six AGA codons, which is the rarest codon in the Pf-5 genome. Substitution of all six AGA codons with preferred Arg codons resulted in a variant of pltR that conferred increased pyoluteorin production and pltL promoter activity. Furthermore, overexpression of tRNAUCUArg, the cognate tRNA for the AGA codon, significantly increased pyoluteorin production by Pf-5. A bias in codon usage has been linked to the regulation of many phenotypes in eukaryotes and prokaryotes but, to our knowledge, this is the first example of the role of a rare codon in the regulation of antibiotic production by a Gram-negative bacterium.Keywords: Pseudomonas protegens, pyoluteorin, rare codon, AGA codon, regulatio

Identification of a differentially expressed gene, ACL, between Meishan × Large White and Large White × Meishan F1 hybrids and their parents

ATP-citrate lyase (ACL), one of the lipogenic enzymes, catalyses the formation of acetyl-coenzyme A (CoA) involved in the synthesis of fatty acid and cholesterol. In pig, very little is known about the ACL gene. In this work, the mRNA differential display technique was used to analyse the differences in gene expression between Meishan and Large White pigs and the F1 hybrids of both direct and reciprocal crosses. Our results show that among the differentially expressed genes ACL is up-regulated in the backfat of the F1 hybrids. After cloning and analysing the fulllength cDNA and the 870 bp 5'-flanking sequence of the porcine ACL gene, a C/T mutation at position -97 bp upstream of the transcription site was detected. Luciferase activity detection showed that this mutation changed the transcriptional activity. In F1 hybrids, the heterozygous genotype CT was more frequent than the homozygous genotypes CC and TT. Real-time PCR analysis showed that in Meishan pigs, ACL mRNA expression was more abundant in individuals with genotype CT than in those with genotype CC or TT or in Large White pigs. These results indicate that the C/T mutation affects ACL mRNA expression, probably via the activator protein 2

Probing material absorption and optical nonlinearity of integrated photonic materials

Optical microresonators with high quality ($Q$) factors are essential to a wide range of integrated photonic devices. Steady efforts have been directed towards increasing microresonator $Q$ factors across a variety of platforms. With success in reducing microfabrication process-related optical loss as a limitation of $Q$, the ultimate attainable $Q$, as determined solely by the constituent microresonator material absorption, has come into focus. Here, we report measurements of the material-limited $Q$ factors in several photonic material platforms. High-$Q$ microresonators are fabricated from thin films of SiO$_2$, Si$_3$N$_4$, Al$_{0.2}$Ga$_{0.8}$As and Ta$_2$O$_5$. By using cavity-enhanced photothermal spectroscopy, the material-limited $Q$ is determined. The method simultaneously measures the Kerr nonlinearity in each material and reveals how material nonlinearity and ultimate $Q$ vary in a complementary fashion across photonic materials. Besides guiding microresonator design and material development in four material platforms, the results help establish performance limits in future photonic integrated systems.Comment: Maodong Gao, Qi-Fan Yang and Qing-Xin Ji contributed equally to this work. 9 pages, 4 figures, 1 tabl