Fabrication of Multicomponent Polymer Nanostructures Containing PMMA Shells and Encapsulated PS Nanospheres in the Nanopores of Anodic Aluminum Oxide Templates

Multi‐component polymer nanomaterials have attracted great attention because of their applications in areas such as biomedicine, tissue engineering, and organic solar cells. The precise control over the morphologies of multi‐component polymer nanomaterials, however, is still a great challenge. In this work, the fabrication of poly(methyl methacrylate)(PMMA)/poly­styrene (PS) nanostructures that contain PMMA shells and encapsulated PS nanospheres is studied. The nanostructures are prepared using a triple solution wetting method with anodic aluminum oxide (AAO) templates. The nanopores of the templates are wetted sequentially by PS solutions in dimethylformamide (DMF), PMMA solutions in acetic acid, and water. The compositions and morphologies of the nanostructures are controlled by the interactions between the polymers, solvents, and AAO walls. This work not only presents a feasible method to prepare multi‐component polymer nanomaterials, but also leads to a better understanding of polymer‐solvent interactions in confined geometries.

     

Stille Catalyst‐Transfer Polycondensation Using Pd‐PEPPSI‐IPr for High‐Molecular‐Weight Regioregular Poly(3‐hexylthiophene)

A commercially available palladium N‐heterocyclic carbene (Pd‐NHC) precatalyst is used to initiate chain‐growth polymerization of 2‐bromo‐3‐hexyl‐5‐trimethylstannylthiophene. The molecular weight of the resultant poly(3‐hexylthiophene) can be modulated (7 to 73 kDa, Đ = 1.14 to 1.53) by varying the catalyst concentration. Mass spectrometry data confirm control over the polymer end groups and ¹H NMR spectroscopy reveals that the palladium catalyst is capable of “ring‐walking”. A linear relationship between M_n and monomer conversion is observed. Atomic force microscopy and X‐ray scattering verify the regioregular nature of the resultant polythiophene.

     

1,6‐Dinitroperylene Bisimide Dyes: Synthesis,Characterization and Photophysical Properties

1,6‐ and 1,7‐regioisomers of dinitro‐substituted perylene bisimides ( 1a — 1b and 2a — 2b ) were synthesized under mild condition in high yields. The 1,6‐ and 1,7‐regioisomers were successfully isolated from the regioisomeric mixture using conventional methods of separation and subsequently characterized by 500 MHz ¹H NMR spectroscopy. This is the first time when 1,6‐dinitroperylene bisimides ( 1a — 1b ) are obtained in pure form. Furthermore, the photophysical and electrochemical properties of 1 and 2 were found to be almost the same. The nitro functionalities provide stability of n‐type charge carriers by lowering the LUMO to resist ambient oxidation, which may offer potential applications in air‐stable n‐type organic semiconductors.     

A novel titanium dioxide-polydimethylsiloxane plate for phosphopeptide enrichment and mass spectrometry analysis

The phosphorylation of proteins is a major post-translational modification that is required for the regulation of many cellular processes and activities. Mass spectrometry signals of low-abundance phosphorylated peptides are commonly suppressed by the presence of abundant non-phosphorylated peptides. Therefore, one of the major challenges in the detection of low-abundance phosphopeptides is their enrichment from complex peptide mixtures. Titanium dioxide (TiO₂) has been proven to be a highly efficient approach for phosphopeptide enrichment and is widely applied. In this study, a novel TiO₂ plate was developed by coating TiO₂ particles onto polydimethylsiloxane (PDMS)-coated MALDI plates, glass, or plastic substrates. The TiO₂-PDMS plate (TP plate) could be used for on-target MALDI-TOF analysis, or as a purification plate on which phosphopeptides were eluted out and subjected to MALDI-TOF or nanoLC-MS/MS analysis. The detection limit of the TP plate was ∼10-folds lower than that of a TiO₂-packed tip approach. The capacity of the ∼2.5 mm diameter TiO₂ spots was estimated to be ∼10 μg of β-casein. Following TiO₂ plate enrichment of SCC4 cell lysate digests and nanoLC-MS/MS analysis, ∼82% of the detected proteins were phosphorylated, illustrating the sensitivity and effectiveness of the TP plate for phosphoproteomic study.     

Separation and Migration Behavior of Dichlorophenols in β‐Cyclodextrin‐Modified Capillary Zone Electrophoresis

The separation and migration behavior of six isomeric dichlorophenols (DCPs) in cyclodextrin‐modified capillary zone electrophoresis (CD‐CZE) using a phosphate‐borate buffer at alkaline pH with β‐CD and hydroxypropyl‐β‐CD (HP‐β‐CD) as electrolyte modifiers were investigated. The influence of buffer pH and the concentration of β‐cyclodextrins were examined. The results indicate that baseline separation of six isomeric DCPs can be achieved with addition of β‐CD concentration in the range of 2.0‐10 mM or HP‐β‐CD concentration in the range of 4.0‐10 mM at pH 10.0. Binding constants of DCPs to β‐CDs were evaluated for a better understanding of the interaction of DCPs with β‐CDs.     

Detection of carcinoembryonic antigen using functional magnetic and fluorescent nanoparticles in magnetic separators

We combined a sandwich immunoassay, anti-CEA/CEA/anti-CEA, with functional magnetic (~80 nm) and fluorescent (~180 nm) nanoparticles in magnetic separators to demonstrate a detection method for carcinoembryonic antigen (CEA). Determination of CEA in serum can be used in clinical diagnosis and monitoring of tumor-related diseases. The CEA concentrations in samples were deduced and determined based on the reference plot using the measured fluorescent intensity of sandwich nanoparticles from the sample. The linear range of CEA detection was from 18 ng/mL to 1.8 pg/mL. The detection limit of CEA was 1.8 pg/mL. In comparison with most other detection methods, this method had advantages of lower detection limit and wider linear range. The recovery was higher than 94%. The CEA concentrations of two serum samples were determined to be 9.0 and 55 ng/mL, which differed by 6.7% (9.6 ng/mL) and 9.1% (50 ng/mL) from the measurements of enzyme-linked immunosorbent assay (ELISA), respectively. The analysis time can be reduced to one third of ELISA. This method has good potential for other biomarker detections and biochemical applications.     

Investigation of Cu<Subscript>0.5</Subscript>Ni<Subscript>0.5</Subscript>/Nb interface transparency by using current-perpendicular-to-plane measurement

A direct determination of the interfacial transparency on the basis of current-perpendicular-to-plane (CPP) resistances for Cu_0.5Ni_0.5/Nb layered system is presented. This particular realization has substantial significance for understanding the interfacial transport in such heterostructures. The unexpected large critical thickness for this weak ferromagnetic containing system can be attributed to the strong pair-breaking effect as a result of the high interfacial transparency. Besides, the strong pair-breaking also plays a decisive role in the occurrence of the dimensionality crossover of the temperature dependent upper critical magnetic field.     

Spontaneous CP violating phase as the phase in PMNS matrix

We study the possibility of identifying the CP violating phases in the PMNS mixing matrix in the lepton sector and also that in the CKM mixing matrix in the quark sector with the phase responsible for the spontaneous CP violation in the Higgs potential, and some implications. Since the phase in the CKM mixing matrix is determined by experimental data, the phase in the lepton sector is also fixed. The mass matrix for neutrinos is constrained, leading to constraints on the Jarlskog CP violating parameter J, and the effective mass 〈m _ββ 〉 for neutrinoless double beta decay. The Yukawa couplings are also constrained. Different ways of identifying the phases have different predictions for \(\mu\to e e\bar{e}\) and \(\tau\to l_{1} l_{2} \bar{l}_{3}\). Future experimental data can be used to distinguish different models.     

Quantum key distribution protocol using dense coding of three-qubit W state

The three-qubit W state, with an important feature that each pair of it’s qubits has the same and maximum amount of bipartite entanglement, can be reduced to an entangled 2-qubit system if one of its qubits is lost. Recently, Xue et al. proposed a three-party quantum secret sharing (QSS) protocol based on the three-qubit W state [Chinese Phys. 15, 7 (2006)]. Also, Joo et al. proposed a pair-wise quantum key distribution protocol among three users based on a special measurement on the three-qubit W state [eprint arXiv:quant-ph/0204003v2 (2002)]. This study aims to propose a novel quantum key distribution protocol (QKDP) for arbitrary two communications based on the dense coding and the special measurement of three-qubit W state with the X basis and the Z basis.     

On the action of permutations on distances between values of rational functions mod p

For the finite field Fp one may consider the distance between r₁(n) and r₂(n), where r₁, r₂ are rational functions in Fp(x). We study the effect to such distances by applying all possible permutations to the elements.