Universal expansions of scattering amplitudes for gravitons, gluons and Goldstone particles

Tree-level scattering amplitudes for gravitons, gluons and Goldstone particles in any dimensions are strongly constrained by basic principles, and they are intimately related to each other via various relations. We study two types of "universal expansions" with respect to gauge bosons and Goldstone bosons: the former express tree amplitudes in Einstein gravity (Yang-Mills) as linear combinations of single-trace Einstein-Yang-Mills (Yang-Mills-$\phi^3$) amplitudes with coefficients given by Lorentz products of polarizations and momenta; the latter express tree amplitudes in non-linear sigma model, (Dirac-)Born-Infeld and a special Galileon theory, as linear combinations of single-trace mixed amplitudes with particles of lower "degree of Adler's zero" and coefficients given by products of Mandelstam variables. We trace the origin of gauge-theory expansions to the powerful uniqueness theorem based on gauge invariance, and expansions in effective field theories can be derived from gauge-theory ones via a special dimension reduction.Comment: 8 pages, 1 figur

The Inhibitory Effect of Regulatory T Cells on the Intimal Hyperplasia of Tissue-Engineered Blood Vessels in Diabetic Pigs

Severe inflammatory response and functional impairment of endothelial progenitor cells (EPCs) often lead to the implantation failure of EPC-captured tissue-engineered blood vessels (TEBVs) in diabetes. Regulatory T cells (Treg cells) are the most important inhibitory immune cells, but their effects in angiogenesis remain undefined, and the differences in the microenvironment may be an important reason. Here, we constructed a TEBV coated with an anti-CD34 antibody-functionalized heparin-collagen multilayer (anti-CD34 antibody-modified TEBV) using layer-by-layer self-assembly. Then, TEBVs were implanted into diabetic pigs. All TEBVs remained unobstructed 60 days after implantation, although varying degrees of intimal hyperplasia were detectable. Severe intimal hyperplasia was observed in the control group and peripheral injection of Treg cells group. Intravenous injection of Treg cells significantly inhibited intimal hyperplasia, inflammation, and cell apoptosis. Moreover, intravenous injection increased the proportion of circulating EPCs, while peripheral injection did not have these effects and reduced microvessel density around the TEBV. Interestingly, many Nestin+ cells could be detected in TEBVs, most of which were fusiform, showing the characteristics of smooth-muscle cells. Treg cell intravenous transplantation markedly reduced the number of Nestin+ cells in the TEBV. In conclusion, Treg cells inhibited the intimal hyperplasia of TEBVs in diabetic pigs by promoting EPC mobilization, anti-inflammatory action, and cellular protection

Nose-to-brain delivery of self-assembled curcumin-lactoferrin nanoparticles: Characterization, neuroprotective effect and in vivo pharmacokinetic study

Curcumin (CUR) is a natural polyphenol extract with significant antioxidant and anti-inflammatory effects, which indicates its great potential for neuroprotection. Lactoferrin (LF), a commonly used oral carrier and targeting ligand, has not been reported as a multifunctional nanocarrier for nose-to-brain delivery. This study aims to develop a nose-to-brain delivery system of curcumin-lactoferrin nanoparticles (CUR-LF NPs) and to further evaluate the neuroprotective effects in vitro and brain accumulation in vivo. Herein, CUR-LF NPs were prepared by the desolvation method with a particle size of 84.8 ± 6.5 nm and a zeta potential of +22.8 ± 4.3 mV. The permeability coefficient of CUR-LF NPs (4.36 ± 0.79 × 10−6 cm/s) was 50 times higher than that of CUR suspension (0.09 ± 0.04 × 10−6 cm/s) on MDCK monolayer, indicating that the nanoparticles could improve the absorption efficiency of CUR in the nasal cavity. Moreover, CUR-LF NPs showed excellent protection against Aβ25-35-induced nerve damage in PC12 cells. In vivo pharmacokinetic studies showed that the brain-targeting efficiency of CUR-LF NPs via IN administration was 248.1%, and the nose-to-brain direct transport percentage was 59.7%. Collectively, nose-to-brain delivery of CUR-LF NPs is capable of achieving superior brain enrichment and potential neuroprotective effects

Kinematic numerators from the worldsheet : cubic trees from labelled trees

In this note we revisit the problem of explicitly computing tree-level scattering amplitudes in various theories in any dimension from worldsheet formulas. The latter are known to produce cubic-tree expansion of tree amplitudes with kinematic numerators automatically satisfying Jacobi-identities, once any half-integrand on the worldsheet is reduced to logarithmic functions. We review a natural class of worldsheet functions called "Cayley functions", which are in one-to-one correspondence with labelled trees, and natural expansions of known half-integrands onto them with coefficients that are particularly compact building blocks of kinematic numerators. We present a general formula expressing kinematic numerators of all cubic trees as linear combinations of coefficients of labelled trees, which satisfy Jacobi identities by construction and include the usual combinations in terms of master numerators as a special case. Our results provide an efficient algorithm, which is implemented in a MATHEMATICA package, for computing all tree amplitudes in theories including non-linear sigma model, special Galileon, Yang-Mills-scalar, Einstein-Yang-Mills and Dirac-Born-Infeld

Serologic survey of the pandemic H1N1 2009 virus in Guangdong Province, China: a cross sectional study.

BACKGROUND: Relying on surveillance of clinical cases limits the ability to understand the full impact and severity of an epidemic, which urges a deep insight into the serological evidence of infection and transmission feature of pandemic H1N1 2009 (pH1N1) virus in Guangdong province. METHODS: In this cross-sectional serological survey, serum samples were collected by multi-stage stratified random sampling in Jan 2010. Antibody titers were measured by hemagglutination inhibition (HI) assay. Age-specific and region-specific prevalence were calculated based on the results of HI assay (positive, HI titer≥1:40). RESULTS: A total of 4,319 serum samples had been collected from subjects without vaccination with pH1N1 vaccine. The seroprevalence was 22.82% (985/4,319). By contrast, there was a marked spatial heterogeneity in prevalence. The seroprevalence was 27.3% in large city, 21.4% in medium cities, higher than that of 20.2% in rural areas. The seroprevalence was highest in 11-20 age group (32.8%), however, in those above 60 years of age group, which was 12.6%, lower than other age groups. On the other hand, antibody titers to pH1N1 virus were highest in school children, which were followed by a gradual decrease in adult. However, in the elderly groups from cities, especially from large city, the antibody titer to pH1N1 increased significantly and reached a much higher level. CONCLUSION: Our results showed that the prevalence for pH1N1 was correlated with age and population density. Preexisting antibody may have protected the very old from pH1N1 infection, while original antigenic sin and immunosenescence may have contributed to greater severity once infected. These should be considered when studying the pathogenesis and transmission of influenza virus and formulating strategies on vaccination and treatment

An electron deficiency strategy for enhancing hydrogen evolution on CoP nano-electrocatalysts

Optimizing the hydrogen adsorption on electrodes is one of the most effective strategies to promote the hydrogen evolution reaction (HER). In recent years, cobalt phosphides (CoP) have been identified as a promising catalyst for HER in acid. However, the hydrogen adsorption on CoP is strong and a considerable overpotential has to be applied to enable HER. Here, we report a strategy to weaken the hydrogen adsorption on CoP through an electron deficiency in CoP induced by Au@CoP core/shell structure. A weakened hydrogen adsorption is confirmed by the density functional theory (DFT) calculation. Au@CoP gave an overpotential (η) of 160 mV at the current density of 1 mA cm−2CoP, which is about 50 mV less than pure CoP. It also exhibited a turn-over frequency (TOF) value of 0.68 s−1 per active site at η = 150 mV, which is more than 4 times higher than CoP. The strategy reported here holds potential to be extended to other electrodes for optimizing their hydrogen adsorption for HER.NRF (Natl Research Foundation, S’pore)MOE (Min. of Education, S’pore

Variance analysis of the effects of block, Al, P, and clone on enzyme activities in roots.

<p>Variance analysis of the effects of block, Al, P, and clone on enzyme activities in roots.</p

Variance analysis of the effects of block, Al, P, and clone on Al-induced secretion of organic acids from roots.

<p>Variance analysis of the effects of block, Al, P, and clone on Al-induced secretion of organic acids from roots.</p