1,265 research outputs found
Effects of Soccer on Stock Markets: The Return-Volatility Relationship
Cataloged from PDF version of article.This paper assesses the effects of domestic soccer teams' performances against foreign rivals on stock market returns as well as on the return-volatility relationship. Data from Chile, Spain, Turkey and the United Kingdom support propositions that soccer teams results in international cups affect stock market returns and the return-volatility relationship. Evidence from Spain and the UK, soccer powerhouses, suggests that losses are associated with lower returns and higher risk aversion but evidence from Chile and Turkey, where soccer is the most important sport but teams are not as successful, reveals that wins are associated with higher returns and lower risk aversion. Crown Copyright (C) 2012 Published by Elsevier Inc. on behalf of Western Social Science Association. All rights reserved
Glycosaminoglycan mimetric peptide nanofibers promote mineralization by osteogenic cells
Cataloged from PDF version of article.Bone tissue regeneration is accomplished by concerted regulation of protein-based extracellular matrix components, glycosaminoglycans (GAGs) and inductive growth factors. GAGs constitute a significant portion of the extracellular matrix and have a significant impact on regulating cellular behavior, either directly or through encapsulation and presentation of growth factors to the cells. In this study we utilized a supramolecular peptide nanofiber system that can emulate both the nanofibrous architecture of collagenous extracellular matrix and the major chemical composition found on GAGs. GAGs and collagen mimetic peptide nanofibers were designed and synthesized with sulfonate and carboxylate groups on the peptide scaffold. The GAG mimetic peptide nanofibers interact with bone morphogenetic protein-2 (BMP-2), which is a critical growth factor for osteogenic activity. The GAG mimicking ability of the peptide nanofibers and their interaction with BMP-2 promoted osteogenic activity and mineralization by osteoblastic cells. Alkaline phosphatase activity, Alizarin red staining and energy dispersive X-ray analysis spectroscopy indicated the efficacy of the peptide nanofibers in inducing mineralization. The multifunctional and bioactive microenvironment presented here provides osteoblastic cells with osteogenic stimuli similar to those observed in native bone tissue
Performance of soccer on the stock market: Evidence fromTurkey
Cataloged from PDF version of article.This paper assesses the effect of soccer success on stock market returns for three major Turkish teams (Besiktas, Fenerbahce and Galatasaray) after certain characteristics of the stock market are controlled for. The empirical evidence presented here suggests that Besikta's win against foreign rivals in the Winner's Cup increases stock market returns. The same effect is not present for the other two big teams (Fenerbahce and Galatasaray). The day of the week effect on the stock market and the relationship between risk and return are also presented. (c) 2006 Elsevier Inc. All rights reserved
Theoretical calculations of second and third-order nonlinear susceptibilities and their corresponding hyperpolarizabilities of a styrylquinolinium dye
The second (Xexp(2)) and third-order (Xexp(3)) susceptibilities of a styrylquinolinium dye (1) have been determined utilizing second-harmonic generation (SHG) and third-harmonic generation (THG) techniques, respectively. The reported measurement findings on Xexp(2) and Xexp(3) have been compared with the theoretical data evaluated here by means of ab-initio quantum mechanical calculations. The electric dipole moments (μ), static dipole polarizabilities (a) and first hyperpolarizabilities (β) have been computed by density functional theory (DFT) at B3LYP/6-311+G(d, p) level. To reveal the frequency-dependent second and third-order microscopic nonlinear optical (NLO) behavior of the title compound, the dynamic dipole polarizabilities, first and second (γ) hyperpolarizabilities have been theoretically investigated using time-dependent Hartree-Fock (TDHF) method. According to the experimental and theoretical results, the values of susceptibilities and the corresponding microscopic coefficients with large non-zero responses make the examined dye promising candidate for NLO applications
Bone-Like Mineral Nucleating Peptide Nanofibers Induce Differentiation of Human Mesenchymal Stem Cells into Mature Osteoblasts
Cataloged from PDF version of article.A bone implant should integrate to the tissue through a bone-like mineralized interface, which requires increased osteoblast activity at the implant-tissue boundary. Modification of the implant surface with synthetic bioinstructive cues facilitates on-site differentiation of progenitor stem cells to functional mature osteoblasts and results in subsequent mineralization. Inspired by the bioactive domains of the bone extracellular matrix proteins and the mussel adhesive proteins, we synthesized peptide nanofibers to promote bone-like mineralization on the implant surface. Nanofibers functionalized with osteoinductive collagen I derived Asp-Gly-Glu-Ala (DGEA) peptide sequence provide an advantage in initial adhesion, spreading, and early commitment to osteogenic differentiation for mesenchymal stem cells (hMSCs). In this study, we demonstrated that this early osteogenic commitment, however, does not necessarily guarantee a priority for maturation into functional osteoblasts. Similar to natural biological cascades, early commitment should be further supported with additional signals to provide a long-term effect on differentiation. Here, we showed that peptide nanofibers functionalized with Glu-Glu-Glu (EEE) sequence enhanced mineralization abilities due to osteoinductive properties for late-stage differentiation of hMSCs. Mussel-inspired functionalization not only enables robust immobilization on metal surfaces, but also improves bone-like mineralization under physiologically simulated conditions. The multifunctional osteoinductive peptide nanofiber biointerfaces presented here facilitate osseointegration for long-term clinical stability. © 2014 American Chemical Society
Amyloid Inspired Self-Assembled Peptide Nanofibers
Cataloged from PDF version of article.Amyloid peptides are important components in many degenerative
diseases as well as in maintaining cellular metabolism. Their unique stable structure
provides new insights in developing new materials. Designing bioinspired selfassembling
peptides is essential to generate new forms of hierarchical nanostructures.
Here we present oppositely charged amyloid inspired peptides (AIPs),
which rapidly self-assemble into nanofibers at pH 7 upon mixing in water caused
by noncovalent interactions. Mechanical properties of the gels formed by selfassembled
AIP nanofibers were analyzed with oscillatory rheology. AIP gels
exhibited strong mechanical characteristics superior to gels formed by self-assembly
of previously reported synthetic short peptides. Rheological studies of gels
composed of oppositely charged mixed AIP molecules (AIP-1 + 2) revealed superior mechanical stability compared to individual
peptide networks (AIP-1 and AIP-2) formed by neutralization of net charges through pH change. Adhesion and elasticity
properties of AIP mixed nanofibers and charge neutralized AIP-1, AIP-2 nanofibers were analyzed by high resolution force−
distance mapping using atomic force microscopy (AFM). Nanomechanical characterization of self-assembled AIP-1 + 2, AIP-1,
and AIP-2 nanofibers also confirmed macroscopic rheology results, and mechanical stability of AIP mixed nanofibers was higher
compared to individual AIP-1 and AIP-2 nanofibers self-assembled at acidic and basic pH, respectively. Experimental results were
supported with molecular dynamics simulations by considering potential noncovalent interactions between the amino acid
residues and possible aggregate forms. In addition, HUVEC cells were cultured on AIP mixed nanofibers at pH 7 and biocompatibility
and collagen mimetic scaffold properties of the nanofibrous system were observed. Encapsulation of a zwitterionic
dye (rhodamine B) within AIP nanofiber network was accomplished at physiological conditions to demonstrate that this network
can be utilized for inclusion of soluble factors as a scaffold for cell culture studies. Copyright © 2012 American Chemical Societ
Second and third-order nonlinear optical behavior of natural pigment: chlorophyll and crocin
To provide an insight into the microscopic second and third-order nonlinear optical (NLO) behavior of chlorophyll a and crocin, we have computed the electric dipole moments (μ), dispersion-free first hyperpolarizabilities (β), frequency-dependent first and second (γ) hyperpolarizabilities at 1064 nm wavelength area using time-dependent Hartree-Fock (TDHF) method. According to ab-initio calculation results, the examined compounds exhibit first and second hyperpolarizabilities with non-zero values, implying second and third-order NLO phenomena
Ab-initio and DFT methodologies for computing hyperpolarizabilities and susceptibilities of highly conjugated organic compounds for nonlinear optical applications
Size-controlled conformal nanofabrication of biotemplated three-dimensional TiO2 and ZnO nanonetworks
Cataloged from PDF version of article.A solvent-free fabrication of TiO2 and ZnO nanonetworks is demonstrated by using supramolecular nanotemplates with high coating conformity, uniformity, and atomic scale size control. Deposition of TiO2 and ZnO on three-dimensional nanofibrous network template is accomplished. Ultrafine control over nanotube diameter allows robust and systematic evaluation of the electrochemical properties of TiO2 and ZnO nanonetworks in terms of size-function relationship. We observe hypsochromic shift in UV absorbance maxima correlated with decrease in wall thickness of the nanotubes. Photocatalytic activities of anatase TiO2 and hexagonal wurtzite ZnO nanonetworks are found to be dependent on both the wall thickness and total surface area per unit of mass. Wall thickness has effect on photoexcitation properties of both TiO2 and ZnO due to band gap energies and total surface area per unit of mass. The present work is a successful example that concentrates on nanofabrication of intact three-dimensional semiconductor nanonetworks with controlled band gap energies
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