The Eccentric Connectivity Index of Dendrimers

Abstract If G is a connected graph with vertex set V , then the eccentric connectivity index of G, ξ C (G), is defined as is the degree of a vertex v and ecc(v) is its eccentricity. We obtain exact formulas for calculating the eccentric connectivity index of dendrimers. Mathematics Subject Classification: 05C05, 05C1

Integrating Second Life into an EFL Program: Students’ Perspectives

Second Life (SL) is a three dimension virtual world imagined and created by its users. To explore various facets of language learning within SL, faculty members of an American university and a Chinese university took an evaluation research approach to search for appropriate ways to integrate SL into an EFL (English as a Foreign Language) program. This paper reports a part of the research efforts with a focus on the Chinese students’ perspectives of an EFL Program in SL. Specifically included in this paper are (a) the Chinese students’ perceived technology readiness to use SL for EFL learning, (b) their perceptions of SL, and (c) the EFL Program implemented in SL. The paper reviews related literature and theoretical support, describes the study’s context and its implementation procedures, and discusses the evaluation results and implications. Finally, the paper shares with the audience some considerations for integrating SL into an EFL progra

Opening Fukushima floodgates: Modelling 137Cs impact in marine biota.

Nº Artículo 112645A numerical model was applied to simulate the transport of 137Cs released with the waters which were used to cool Fukushima reactors. These stored waters will be released to the Pacific Ocean according to Japanese gov ernment plans. The radionuclide transport model is Lagrangian and includes radionuclide interactions with sediments and an integrated dynamic foodweb model for biota uptake. Calculations made from a conservative approach indicate that expected concentrations in sediments and marine fish would be orders of magnitude below those detected after Fukushima accident and also lower than those resulting from global fallout background

Fabrication of Porous TiO2 Hollow Spheres and Their Application in Gas Sensing

In this work, porous TiO2 hollow spheres with an average diameter of 100 nm and shell thickness of 20 nm were synthesized by a facile hydrothermal method with NH4HCO3 as the structure-directing agent, and the formation mechanism for this porous hollow structure was proved to be the Ostwald ripening process by tracking the morphology of the products at different reaction stages. The product was characterized by SEM, TEM, XRD and BET analyses, and the results show that the as-synthesized products are anatase phase with a high surface area up to 132.5 m2/g. Gas-sensing investigation reveals that the product possesses sensitive response to methanal gas at 200°C due to its high surface area

Effects of Lycium barbarum polysaccharides with different molecular weights on function of RAW264.7 macrophages

The present study was aimed at investigating the effects of four LBP fractions with different molecular weights (MWs), designated LBP2, LBP3, LBP4 and LBP5, on RAW264.7 macrophages function. Results showed that LBP fractions could significantly enhance the expression of CD86 and MHC-II molecules on RAW264.7 macrophages. LBP3, LBP4 and LBP5 could enhance the production of ROS, NO, TNF-α and IL-6, and the phagocytosis of RAW264.7 macrophages. LBP2 with an MW of larger than 350 kDa could only enhance the secretion of TNF-α. LBP3 enhanced the RAW264.7 macrophages function in a dose-dependent manner and also enhanced the iNOS mRNA expression in the cells. These results demonstrated that the immunomodulatory activity of LBP on RAW264.7 macrophages was closely related to its MW. It indicated that fractions with an MW smaller than 350 kDa were the main active fractions of LBP in enhancing macrophages function

finitesizeeffectontheramanfrequencyofphononsinnanosemiconductors

A comprehensive study on Raman spectroscopy with different excitation wavelengths, sample sizes, and sample shapes for optic phonons (OPs) and acoustic phonons (APs) in polar and non-polar nano-semiconductors has been performed. The study affirms that the finite size effect does not appear in the OPs of polar nano-semiconductors, while it exists in all other types of phonons. The absence of the FSE is confirmed to originate from the long-range Frohlich interaction and the breaking of translation symmetry. The result indicates that the Raman spectra of OPs cannot be used as a method to characterize the scale and crystalline property of polar nano-semiconductors