Pure Blue‐Light Emissive Poly(oligofluorenes) with Bifunctional POSS in the Main Chain

Emission of conjugated polymers is known to undergo bathochromic shift from solution to film formation due to π–π stacking in the solid state. In this report, a series of pearl‐necklace‐like hybrid polymers is designed via the hydrosilylation condensation between bifunctional polyhedral oligomeric silsesquioxanes ( B‐POSS ) and oligofluorene segments. Optoelectronic analyses unequivocally show that the presence of these interconnecting B‐POSS can effectively reduce red‐shift in photoluminescence and electroluminescence during film formation. These hybrid poly(oligofluorenes) display stable blue emission with high color purity. Thermal analyses also indicate that they are vitrified polymers with high glass transition temperature (up to 125 °C). We believe that this strategy can be extended to other conjugated systems to control color purity in electroactive materials and holds promise as new emissive materials for various applications.

     

Shorter identity-based encryption via asymmetric pairings

We present efficient identity-based encryption (IBE) under the symmetric external Diffie–Hellman (SXDH) assumption in bilinear groups; our scheme also achieves anonymity. In our IBE scheme, all parameters have constant numbers of group elements, and are shorter than those of previous constructions based on decisional linear (DLIN) assumption. Our construction uses both dual system encryption (Waters, CRYPTO 2009) and dual pairing vector spaces (Okamoto and Takashima, Pairing 2008; ASIACRYPT 2009). Specifically, we show how to adapt the recent DLIN-based instantiation of Lewko (EUROCRYPT 2012) to the SXDH assumption. To our knowledge, this is the first work to instantiate either dual system encryption or dual pairing vector spaces under the SXDH assumption. Furthermore, our work could be extended to many other functional encryption. In Particular, we show how to instantiate our framework to inner product encryption and key-policy functional encryption. All parameters of our constructions are shorter than those of DLIN-based constructions.     

Interaction of copper with sulfur on the sulfur-terminated Si(1 1 1)-(7 × 7) surface

The adsorption of S₂ on the Si(1 1 1)-(7 × 7) surface and the interaction of copper and sulfur on this sulfur-terminated Si(1 1 1) surface have been studied using synchrotron irradiation photoemission spectroscopy and scanning tunneling microscopy. The adsorption of S₂ at room temperature results in the passivation of silicon dangling bonds of Si(1 1 1)-(7 × 7) surface. Excessive sulfur forms S_n species on the surface. Copper atoms deposited at room temperature directly interact with S-adatoms through the formations of Cu-S bonds. Upon annealing the sample at 300 °C, CuS_x nanocrystals were produced on the sulfur-terminated Si(1 1 1) surface.     

Development of a Pre‐assembled Through‐Bond Energy Transfer (TBET) Fluorescent Probe for Ratiometric Sensing of Anticancer Platinum(ll) Complexes

Fluorescence microscopy has emerged as an attractive technique to probe the intracellular processing of Pt‐based anticancer compounds. Herein, we reported the first through‐bond energy transfer (TBET) fluorescent probe NPR1 designed for sensitive detection and quantitation of Pt^II complexes. The novel TBET probe was successfully applied for ratiometric fluorescence imaging of anticancer Pt^II complexes such as cisplatin and JM118 in cells. Capitalizing on the ability of the probe to discriminate between Pt^II complexes and their Pt^IV derivatives, the probe was further applied to study the activation of Pt^IV prodrug complexes that are known to release active Pt^II species after intracellular reduction.     

Identification of a novel series of alkylitaconic acids in wood cultures of Ceriporiopsis subvermispora by gas chromatography/mass spectrometry.

A novel series of long-chain unsaturated dicarboxylic acids consisting of a long aliphatic chain attached to the C-3 position of itaconic acid has been identified by gas chromatography/mass spectrometry during in vitro decay of eucalypt wood by the white-rot basidiomycete Ceriporiopsis subvermispora. The major compounds were identified as tetradecyl-, 7-hexadecenyl- and hexadecylitaconic acids by their mass fragmentation patterns. Other members of the same compound series, identified as dodecanyl-, tridecanyl-, tetradecenyl-, pentadecanyl-, octadecenyl- and octadecanylitaconic acids, were present in very minor amounts or traces. Whereas hexadecenylitaconic acid has already been reported in cultures of C. subvermispora, to our knowledge this is the first report of the presence of the other alkylitaconic acids in fungal cultures. These new alkylitaconic-type metabolites may constitute a source for peroxidizable lipids involved in lignin degradation during wood decay by C. subvermispora and other white-rot basidiomycetes.     

A simple proof of the Uncertainty Principle for compact groups

We give a simple proof of the Uncertainty Principle for finite nonabelian groups, which generalizes directly to compact groups.     

The pros and cons of apoptosis assays for use in the study of cells, tissues, and organs.

Programmed cell death or apoptosis occurs in many tissues during normal development and in the normal homeostasis of adult tissues. Apoptosis also plays a significant role in abnormal development and disease. Increased interest in apoptosis and cell death in general has resulted in the development of new techniques and the revival of old ones. Each assay has its advantages and disadvantages that can render it appropriate and useful for one application, but inappropriate or difficult to use in another. Understanding the strengths and limitations of the assays would allow investigators to select the best methods for their needs.     

Catalytic formation of hydrogen peroxide from H2 and O2 over hydrogen transfer agent-anchored Pd°/beta zeolites

Hydrogen transfer agents (HTAs) have been successfully anchored on Pd°/H-beta zeolite and exhibit enhanced catalytic activity in the formation of H₂O₂ from H₂ and O₂ at atmospheric pressure compared with that of the Pd°/H-beta and the HTA included catalysts.