Random Mass Dirac Fermions in Doped Spin-Peierls and Spin-Ladder systems: One-Particle Properties and Boundary Effects

Quasi-one-dimensional spin-Peierls and spin-ladder systems are characterized by a gap in the spin-excitation spectrum, which can be modeled at low energies by that of Dirac fermions with a mass. In the presence of disorder these systems can still be described by a Dirac fermion model, but with a random mass. Some peculiar properties, like the Dyson singularity in the density of states, are well known and attributed to creation of low-energy states due to the disorder. We take one step further and study single-particle correlations by means of Berezinskii's diagram technique. We find that, at low energy $\epsilon$, the single-particle Green function decays in real space like $G(x,\epsilon) \propto (1/x)^{3/2}$. It follows that at these energies the correlations in the disordered system are strong -- even stronger than in the pure system without the gap. Additionally, we study the effects of boundaries on the local density of states. We find that the latter is logarithmically (in the energy) enhanced close to the boundary. This enhancement decays into the bulk as $1/\sqrt{x}$ and the density of states saturates to its bulk value on the scale $L_\epsilon \propto \ln^2 (1/\epsilon)$. This scale is different from the Thouless localization length $\lambda_\epsilon\propto\ln (1/\epsilon)$. We also discuss some implications of these results for the spin systems and their relation to the investigations based on real-space renormalization group approach.Comment: 26 pages, LaTex, 9 PS figures include

The chalcone butein from Rhus verniciflua Stokes inhibits clonogenic growth of human breast cancer cells co-cultured with fibroblasts

BACKGROUND: Butein (3,4,2',4'-tetrahydroxychalone), a plant polyphenol, is a major biologically active component of the stems of Rhus verniciflua Stokes. It has long been used as a food additive in Korea and as an herbal medicine throughout Asia. Recently, butein has been shown to suppress the functions of fibroblasts. Because fibroblasts are believed to play an important role in promoting the growth of breast cancer cells, we investigated the ability of butein to inhibit the clonogenic growth of small numbers of breast cancer cells co-cultured with fibroblasts in vitro. METHODS: We first measured the clonogenic growth of small numbers of the UACC-812 human breast cancer cell line co-cultured on monolayers of serum-activated, human fibroblasts in the presence of butein (2 μg/mL) or various other modulators of fibroblast function (troglitazone-1 μg/mL; GW9662-1 μM; meloxican-1 μM; and 3,4 dehydroproline-10 μg/mL). In a subsequent experiment, we measured the dose-response effect on the clonogenic growth of UACC-812 breast cancer cells by pre-incubating the fibroblasts with varying concentrations of butein (10 μg/ml-1.25 μg/mL). Finally, we measured the clonogenic growth of primary breast cancer cells obtained from 5 clinical specimens with normal fibroblasts and with fibroblasts that had been pre-treated with a fixed dose of butein (2.5 μg/mL). RESULTS: Of the five modulators of fibroblast function that we tested, butein was by far the most potent inhibitor of clonogenic growth of UACC-812 breast cancer cells co-cultured with fibroblasts. Pre-treatment of fibroblasts with concentrations of butein as low as 2.5 μg/mL nearly abolished subsequent clonogenic growth of UACC-812 breast cancer cells co-cultured with the fibroblasts. A similar dose of butein had no effect on the clonogenic growth of breast cancer cells cultured in the absence of fibroblasts. Significantly, clonogenic growth of the primary breast cancer cells was also significantly reduced or abolished when the tumor cells were co-cultured with fibroblasts that had been pre-treated with a fixed dose of butein. CONCLUSION: We conclude that fibroblasts pre-treated with non-toxic doses of butein (a natural herbal compound) no longer support the clonogenic growth of small numbers of primary breast cancer cells seeded into co-cultures. These results suggest that interference with the interaction between fibroblasts and breast cancer cells by the natural herbal compound, butein, should be further investigated as a novel experimental approach for possibly suppressing the growth of micrometastases of breast cancer

PERENCANAAN STRATEGI SISTEM INFORMASI PADA PT. A.J. CENTRAL ASIA RAYA

PERENCANAAN STRATEGI SISTEM INFORMASI PADA PT. A.J. CENTRAL ASIA RAY

A Stylistic and Pedagogical Analysis of Selected Solo Piano Works by Naoko Ikeda

Naoko Ikeda (b.1964) is the first Japanese composer to sign with an American publisher, The Willis Music Company, which has exclusively published her works in the United States since 2004. As of this writing, Ikeda’s pedagogical compositions have begun to gain global appeal and are increasingly utilized in lessons, concerts, festivals, lectures, examinations, and competitions across Japan, the United States, Canada, and Europe. This document explores Naoko Ikeda’s solo piano works, presents an overview of her solo piano music, and analyzes 38 pieces from 6 selected collections from her output. Chapter 1 presents the overview, purpose, need, limitations, and procedures of the study, and includes a review of related literature. Chapter 2 offers a biographical sketch of Naoko Ikeda, shedding light on her musical upbringing and significant career accomplishments to date. Chapter 3 outlines Ikeda’s eclectic compositional style, which draws inspiration from a variety of Eastern and Western musical genres and styles. This chapter also briefly surveys her published works for piano to determine the development of her compositional style over the last two decades. To supplement this survey, chronological and leveled guides to Ikeda’s complete piano works to date are provided in Appendices A and B. Appendices C and D provide the Institutional Review Board’s Approval Letter and the Interview Guide used to conduct email interviews with Ikeda. Appendix E outlines Hal Leonard’s Copyright Permission Letter to reproduce Ikeda’s music in this document. Chapters 4 through 9 analyze 38 solo piano pieces from 6 collections: Shoukei, Book 1 (2004), Shoukei, Book 2 (2005), Moving Pictures (2006), Celestial Dreams (2007), Miyabi (2012), and Aya (2022). For each of these 6 collections, the author offers a brief discussion on the background of the piece, a compositional analysis, and a pedagogical analysis. Chapter 10 concludes the study, summarizes Ikeda’s compositional style and contributions as a composer, and suggests potential avenues for future research. By exploring Ikeda’s piano music, this document addresses the dearth of academic literature on Ikeda’s works, acknowledges her growing global importance as an educational composer, and serves as a resource for teachers and pianists interested in Ikeda’s music