Synthesis of N-modified sTn analogs and evaluation of their immunogenicities by microarray-based immunoassay

A series of sTn derivative-keyhole limpet hemocyanin (KLH) conjugates were synthesized, and their immunogenicities were evaluated by corresponding IgG production. To achieve a high-throughput screening immunoassay, a glycan microarray with sTn and its analogs was used to detect the production of corresponding antibodies in mouse sera. The immunoassay results revealed that the derived sTn antigens are generally more immunogenic than the parent sTn antigen. The N-propionyl sTn antigen was the most immunogenic among the sTn derivatives investigated, and its antiserum was cross-reactive with natural sTn. These results indicate that N-propionyl sTn may serve as a viable vaccine candidate to produce antibody for detection of sTn antigen.     

Ampholyte polystyrene spheres self-regulated deposition of noble metal nanoparticles for catalyst applications

The polystyrene (PS) spheres having dual functional groups were synthesized using emulsifier-free emulsion polymerization based on St/potassium persulfate/water system in the presence of V-50 as co-initiator. Fourier transform infrared (FTIR) confirms the presence of the sulfate and the amino groups on the surfaces of PS spheres. Transmission electron microscopy and X-ray photoelectron spectra revealed that the PS spheres were successfully deposited with catalytic palladium (Pd) or gold (Au) nanoparticles (NPs). The reduction of 4-nitroaniline to 4-phenylenediamine used as a model reaction was performed for catalysis studies and examined by ultraviolet. It was found that both Au and Pd PS dispersions show high catalytic activity. The Pd PS dispersion of 200 μl with only Pd content of 1.09 wt.% exhibits an excellent catalytic effect superior to the commercial Pd/C catalyst, i.e., less than 35 s taken for the completion of the reduction of 4-nitroaniline.     

Preparation of sulfate- and carboxyl-functionalized magnetite/polystyrene spheres for further deposition of gold nanoparticles

A synthetic method developed for preparation of sulfate- and carboxyl-functionalized magnetite/polystyrene (Fe₃O₄/PS) spheres that can be further decorated with gold (Au) nanoparticles is reported. By using emulsifier-free emulsion polymerization based on potassium persulfate (KPS)/methyl acrylic acid (MAA)/water system in the presence of Fe₃O₄/PS spheres used as the seeds, PMAA-coated magnetic Fe₃O₄-PS spheres were readily obtained. The sulfate group is inherent in KPS for initiating the polymerization of PMAA, and eventually it acts as the reducing agent for the deposition of Au nanoparticles. The carboxyl group, on the other hand, could seemingly contribute to immobilize Au nanoparticles precipitated. The morphologies, magnetic properties, and characteristics of oleate-stabilized Fe₃O₄ nanoparticles, Fe₃O₄/PS spheres, PMAA-coated Fe₃O₄/PS spheres, and Au-decorated resultant spheres were respectively studied using transmission electron microscopy, X-ray diffraction, Fourier transform infrared, and superconducting quantum interference device magnetometer.     

DCDHF Fluorophores for Single‐Molecule Imaging in Cells

There is a persistent need for small‐molecule fluorescent labels optimized for single‐molecule imaging in the cellular environment. Application of these labels comes with a set of strict requirements: strong absorption, efficient and stable emission, water solubility and membrane permeability, low background emission, and red‐shifted absorption to avoid cell autofluorescence. We have designed and characterized several fluorophores, termed “DCDHF” fluorophores, for use in live‐cell imaging based on the push–pull design: an amine donor group and a 2‐dicyanomethylene‐3‐cyano‐2,5‐dihydrofuran (DCDHF) acceptor group, separated by a π‐rich conjugated network. In general, the DCDHF fluorophores are comparatively photostable, sensitive to local environment, and their chemistries and photophysics are tunable to optimize absorption wavelength, membrane affinity, and solubility. Especially valuable are fluorophores with sophisticated photophysics for applications requiring additional facets of control, such as photoactivation. For example, we have reengineered a red‐emitting DCDHF fluorophore so that it is dark until photoactivated with a short burst of low‐intensity violet light. This molecule and its relatives provide a new class of bright photoactivatable small‐molecule fluorophores, which are needed for super‐resolution imaging schemes that require active control (here turning‐on) of single‐molecule emission.     

THE WELL-POSEDNESS AND ASYMPTOTICS OF MULTI-DIMENSIONAL QUANTUM HYDRODYNAMICS

The multi-dimensional quantum hydrodynamic equations for charge transport in ultra-small electronic devices like semiconductors, where quantum effects （like particle tunnelling through potential barriers and built-up in quantum wells） take place, is considered in the present paper, and the recent progress on well-posedness, stability analysis, and small scaling limits are reviewed.     

ZnSe/ZnCdSe heterostructure nanowires

The authors report the growth of high density ZnSe/ZnCdSe heterostructure nanowires on oxidized Si substrate. It was found that the as-grown nanowires were tapered with mixture of cubic zinc-blende and hexagonal wurtzite structures. It was also found that photoluminescence intensities observed from these ZnSe/ZnCdSe heterostructure nanowires were much larger than observed from the homogeneous ZnSe nanowires. Furthermore, it was found that activation energies for the nanowires with well widths of 6, 12, 18 and 24 nm were 22, 41, 67 and 129 meV, respectively.