Formation of Macropore and Three-Dimensional Nanorod Array in p-Type Silicon

We carried out a study on the change in pore wall thickness depending on the current density in p-type silicon. We attempted the formation of a uniform macropore or nanorod array with a high aspect ratio in p-type silicon by electrochemical etching through the optimization of the hydrogen fluoride (HF)/organic electrolyte composition and the design of the mask pattern. The electrochemical etching of p-type silicon in the HF : dimethylsulfoxide (DMSO) : deionized (DI) water 1/4 1 : 5 : 5 electrolyte can control the velocity of a reaction between an electrolyte and a hole necessary for the electrochemical etching of silicon through the mixing of the protic property of DI water and the aprotic property of DMSO. In this study, we fabricated a p-type silicon nanorod array of three-dimensional structures with an approximately 350nm diameter from macroporous Si by applying two-step currents (40 mA, 200 s + 38 mA, 1600 s) to a 1.8 cm2 circular area using an optimized HF : DMSO : DI water 1/4 1 : 5 : 5 electrolyte composition. © 2010 The Japan Society of Applied Physics.1

Isomer structure-optical property relationships for naphthalene-based poly(perfluorocyclobutyl ether)s

Synthesis and characterization of new naphthalene-based PFCB aryl ether polymeric isomers with 1,5-, 1,6-, 2,6-, and 2,7-linkages were described. Monomers of perfluorocyclobutane (PFCB) poly(aryl ether)s, 1,5-, 1,6-, 2,6-, and 2,7-bis(trifluorovinyloxy)naphthalene, were synthesized from dihydroxynaphthalenes in two steps and polymerized by 2π + 2π step-growth cyclopolymerization. The naphthalene-based PFCB polymers (PFNs) had a relatively high Tg in the range 106−144 °C and excellent thermal stability at temperatures up to 400 °C. Among PFN polymeric isomers, Tg of the 1,5-linked PFCB polymer (1,5-PFN) was 30−40 °C higher than those of the other naphthalene isomers due to its high steric hindrance around the backbone. The refractive index and birefringence of the PFN polymers in the form of spin-coated films were determined. The PFN isomeric polymers showed tunability in refractive index and the birefringence of the order of 1,5 < 1,6 < 2,6 < 2,7-PFN and 1,5 < 1,6 < 2,7 < 2,6-PFN, respectively. PFN isomers had low birefringences below 0.002 except 2,6-PFN. The lowest value in birefringence was 0.0008 of 1,5-PFN due to its highly kinked structure. Plastic optical fibers of homopolymers, 1,5- and 2,7-PFN, and copolymers, 2,7-co-1,5-PFN and 2,7-PFN-co-6F−PF, were prepared, and optical losses and windows of them were observed. The attenuation loss of PFN polymers was about 0.17−0.27 dB/cm at the wavelength of near-IR optical sources. 1,5-PFN had a lower optical loss than 2,7-PFN. The optical loss of the 2,7-co-1,5-PFN copolymer was effectively reduced compared with that of 2,7-PFN. The lowest optical loss polymer for PFCB POF was 2,7-PFN-co-6F-PF of 0.07 dB/cm at the wavelength of the optical loss window and 0.17 dB/cm at 1300 nm.This work was financially supported by the Ministry of Science and Technology, National Research Laboratory program of KOSEF, and Heeger Center for Advanced Materials (HCAM)

Prognostic significance of E-cadherin and N-cadherin expression in Gliomas

Abstract Background Epithelial-mesenchymal transition (EMT), principally involving an E-cadherin to N-cadherin shift, linked to tumor invasion or metastasis, and therapeutic resistance in various human cancer. A growing body of recent evidence has supported the hypothesis that EMT play a crucial role in the invasive phenotype of gliomas. To evaluate the prognostic connotation of EMT traits in glioma, expression of E-cadherin and N-cadherin was explored in a large series of glioma patients in relation to patient survival rate. Methods Expressions of E- and N-cadherin were examined using immunohistochemical analysis in 92 glioma cases diagnosed at our hospital. These markers expressions were also explored in 21 cases of fresh frozen glioma samples and in glioma cell lines by Western blot analysis. Results Expression of E-cadherin was observed in eight cases (8.7%) with weak staining intensity in the majority of the immunoreactive cases (7/8). Expression of N-cadherin was identified in 81 cases (88.0%) with high expression in 64 cases (69.5%). Fresh frozen tissue samples and glioma cell lines showed similar results by Western blot analysis. There was no significant difference in either overall survival (OS) or progression-free survival (PFS) according to E-cadherin expression (P > 0.05). Although the OS rates were not affected by N-cadherin expression levels (P = 0.138), PFS increased in the low N-cadherin expression group with marginal significance (P = 0.058). The survival gains based on N-cadherin expression levels were significantly augmented in a larger series of publicly available REMBRANDT data (P < 0.001). Conclusions E- and N-cadherin, as representative EMT markers, have limited prognostic value in glioma. Nonetheless, the EMT process in gliomas may be compounded by enhanced N-cadherin expression supported by unfavorable prognostic outcomes

Reprogramming anchorage dependency by adherent-to-suspension transition promotes metastatic dissemination

Abstract Background Although metastasis is the foremost cause of cancer-related death, a specialized mechanism that reprograms anchorage dependency of solid tumor cells into circulating tumor cells (CTCs) during metastatic dissemination remains a critical area of challenge. Methods We analyzed blood cell-specific transcripts and selected key Adherent-to-Suspension Transition (AST) factors that are competent to reprogram anchorage dependency of adherent cells into suspension cells in an inducible and reversible manner. The mechanisms of AST were evaluated by a series of in vitro and in vivo assays. Paired samples of primary tumors, CTCs, and metastatic tumors were collected from breast cancer and melanoma mouse xenograft models and patients with de novo metastasis. Analyses of single-cell RNA sequencing (scRNA-seq) and tissue staining were performed to validate the role of AST factors in CTCs. Loss-of-function experiments were performed by shRNA knockdown, gene editing, and pharmacological inhibition to block metastasis and prolong survival. Results We discovered a biological phenomenon referred to as AST that reprograms adherent cells into suspension cells via defined hematopoietic transcriptional regulators, which are hijacked by solid tumor cells to disseminate into CTCs. Induction of AST in adherent cells 1) suppress global integrin/ECM gene expression via Hippo-YAP/TEAD inhibition to evoke spontaneous cell–matrix dissociation and 2) upregulate globin genes that prevent oxidative stress to acquire anoikis resistance, in the absence of lineage differentiation. During dissemination, we uncover the critical roles of AST factors in CTCs derived from patients with de novo metastasis and mouse models. Pharmacological blockade of AST factors via thalidomide derivatives in breast cancer and melanoma cells abrogated CTC formation and suppressed lung metastases without affecting the primary tumor growth. Conclusion We demonstrate that suspension cells can directly arise from adherent cells by the addition of defined hematopoietic factors that confer metastatic traits. Furthermore, our findings expand the prevailing cancer treatment paradigm toward direct intervention within the metastatic spread of cancer