Raman reporter-coated gold nanorods and their applications in multimodal optical imaging of cancer cells

We report the preparation of a kind of surface-enhanced Raman scattering (SERS) tags and explore their applications in multifunctional optical imaging of cancer cells. The proposed nanoparticles (SERS tags) are prepared by connecting dye molecules directly onto the surfaces of gold nanorods through Au–S or Au–N interactions. The dye molecules are used as Raman reporters, while gold nanorods are used as enhanced materials due to their localized surface plasmon resonance effect. Multilayered polymers are further coated onto the surfaces of the nanoparticles to reach better stability and biocompatibility. Gold nanorods with different aspect ratios and different dye molecules conjugated are compared in order to achieve the diversity of SERS tags and find out the optimized condition of SERS tags with the highest signal intensity. Our experiments show that the resulting nanoparticles, which are uptaken by cancer cells, can provide not only dark field cells images but also multiplexing SERS images.     

An integro-differential equation for surface ocean waves with finite depth

An explicit integro-differential equation formulation is derived for surface ocean waves with finite depth. The equation involves only 2D surface variables. For this equation, we establish the stability and existence of solutions, and explain the effect of depth on surface wave properties.     

Eigenstructure assignment for linear parameter-varying systems with applications

The aim of this paper is to show that a recently proposed technique for eigenstructure assignment of linear time-invariant systems can be extended to solve the corresponding eigenstructure assignment problem for linear parameter-varying systems, whose state-space matrices depend on a set of time-varying parameters that are bounded and available online. In particular, the design of eigenstructure assignment is performed without requiring any conditions on the closed-loop eigenvalues, and provides a simple, complete and analytical parametric approach as well as the most degrees of design freedom for the eigenstructure assignment problem of linear parameter-varying systems. A parameter-varying attitude control system of refueling spacecraft in-orbit is used to demonstrate the usefulness and practicality of the proposed approach.     

神经元的形态分类和识别

对神经元特性的认识,最基本问题是神经元的分类.神经元的形态复杂多样,神经元的识别分类问题有相当的困难.对提供的参考数据进行统计分析,将其转化成对应每类神经元的空间形态的指标参数,然后对每个指标进行定性分析和对比分析,确定对各类型神经元细胞识别起关键作用的指标,利用层次分析法、图形截面、几何相似性等分析方法建立神经元的分类模型.分类模型能够将附录提供的神经元进行准确的分类.数据分析采用开源科学计算软件Scilab进行处理,运行环境为Scilab5.2,部分代码采用C#基于VS2008开发.     

Complete q-Moment Convergence of Moving Average Processes under ψ-mixing Assumption

In this paper,we study the complete q-moment convergence of moving average processes under ψ-mixing assumption.The results obtained not only extend some previous known results,but also improve them.     

From HCOOH to CO at Pd electrodes: a surface-enhanced infrared spectroscopy study

The decomposition of HCOOH on Pd surfaces over a potential range of practical relevance to hydrogen production and fuel cell anode operation was probed by combining high-sensitivity in situ surface-enhanced IR spectroscopy with attenuated total reflection and thin-layer flow cell configurations. For the first time, concrete spectral evidence of CO(ad) formation has been obtained, and a new main pathway from HCOOH to CO(ad) involving the reduction of the dehydrogenation product of HCOOH (i.e., CO(2)) is proposed.     

Electrochemical detection of extracellular hydrogen peroxide released from RAW 264.7 murine macrophage cells based on horseradish peroxidase-hydroxyapatite nanohybrids

A new method developed for the reliable determination of extracellular and intracellular H(2)O(2) is very useful for gaining a full understanding of the role that H(2)O(2) plays in pathology and physiology, and the relationship between H(2)O(2) and environmental stresses and lipid peroxidation. This work developed and validated an electrochemical approach for the determination of extracellular H(2)O(2) released from RAW 264.7 murine macrophage cells. This approach is based on the electrocatalytic reduction of the released H(2)O(2) at the biosensor of HRP-HAP/GC, which was fabricated by depositing the horseradish peroxidase-hydroxyapatite (HRP-HAP) nanohybrids on a glassy carbon (GC, 3 mm in diameter) electrode. The biosensor exhibited a rapid response (less than 2 s), a low detection limit (0.1±0.02 μM), a wide linear range (5 μM to 0.82 mM), as well as good stability and repeatability. In addition, the common interfering species, such as uric acid (UA), ascorbic acid (AA), glucose, and 3,4-dihydroxyphenylacetic acid (DOPAC), etc., did not cause any interference due to the use of a low operating potential (-400 mV, versus SCE). Therefore, this work has demonstrated a simple and effective sensing platform for the detection of extracellular H(2)O(2) released from cells such as RAW 264.7 cells, which has potential utility to bioelectroanalytical chemistry, cellular biology, and pathophysiology.     

Extraction tool and matrix effects on arsenic speciation analysis in cell lines

Arsenic glutathione (As–GSH) complexes have been suggested as possible metabolites in arsenic (As) metabolism. Extensive research has been performed on the toxicological and apoptotic effects of As, while few reports exist on its metabolism at the cellular level due to the analytical challenges. In this study, an efficient extraction method for arsenicals from cell lines was developed. Evaluation of extraction tools; vortex, ultrasonic bath and ultrasonic probe and solvents; water, chemicals (methanol and trifluoroacetic acid), and enzymes (pepsin, trypsin and protease) was performed. GSH effect on the stability of As–GSH complexes was studied. Arsenic metabolites in dimethylarsino glutathione (DMA(GS)) incubated multiple myeloma cell lines were identified following extraction. Intracellular GSH concentrations of myeloma cell lines were imitated in the extraction media and its corresponding effect on the stability and distribution of As metabolites was studied. An enhancement in both extraction recoveries and time efficiency with the use of the ultrasonic probe was observed. Higher stabilities for the As species in water, pepsin and trypsin were obtained. The presence of 0.5 mM GSH in the extraction media (PBS, pH 7.4) could not stabilize the As–GSH complexes compared to the 5 mM GSH, where high stabilization of the complexes was observed over a 5 day storage study. Finally, the speciation analysis of the DMA(GS) culture incubated cell lines in the presence or absence of GSH revealed the important role GSH plays in the preservation of DMA(GS) identity. Hence, caution is required during the extraction of arsenicals especially the As–GSH complexes, since their identification is highly dependent on GSH concentration.     

Two New Cyclic Pentapeptides from the Marine‐Derived Fungus Aspergillus versicolor

Two new cyclic pentapeptides, named versicotides A ( 1 ) and B ( 2 ), were obtained from a marine‐derived fungus strain ZLN‐60, identified as Aspergillus versicolor. Their structures were established on the basis of chemical and spectroscopic evidence. Versicotides are new cyclic pentapeptides which contain an L ‐alanine residue, two anthranilic acid (=2‐aminobenzoic acid) residues, and two N‐methyl‐L ‐alanine residues. Antitumor activities were evaluated by the SRB and MTT methods.