Plasma-Assisted Deposition of Au/SiO2 Multi-layers as Surface Plasmon Resonance-Based Red-Colored Coatings

In this work, the expanding thermal plasma chemical vapor deposition in combination with radio frequency magnetron sputtering is used to deposit dielectric/metal multi-layers with controlled size and density of nanoparticles. The multi-layer structure serves the purpose of increasing the nanoparticle number density, without changing the metal particle size, shape and the interparticle distance. The possibility of independently tuning and, therefore, controlling the nanoparticle size and number density allows developing surface plasmon resonance-based deep-colored coatings. The influence of the number of layers, metal surface area coverage, and thickness of the dielectric layer on the multi-layer nanostructure and on the developed color is presented here in detail. The nanoparticle size and distribution have been measured by transmission electron microscopy. Rutherford back-scattering and infra-red transmission spectroscopy have been used to determine the metal surface coverage and the film chemistry, respectively. Optical properties of the nano-composite layers have been investigated by UV-VIS spectroscopy and exhibit an increase in amplitude of the plasmon absorption spectra at a fixed plasmon resonance frequency with an increase in the number of layers.     

Surface Plasmon Assisted Luminescence Enhancement of Ag NP/NWs-Doped SiO2-TiO2-ZrO2:Eu3+ Ternary System

Plasmonics - Non-hydrolytic sol-gel process was employed to prepare Eu3+-doped and silver nanoparticles/nanowires (Ag NP/NWs) co-doped SiO2-TiO2-ZrO2 ternary matrix. XRD, TEM, and SAED analyses...     

蛋白芯片载体表面修饰对探针固定影响的研究

采用3-氨基丙基-三甲氧基硅烷((3-aminopropyl)trimethoxysilane,APTES)、戊二醛(glutaraldehyde,GA)、多聚-L-赖氨酸(poly-L-lysine,PLL)修饰芯片载体表面,对3种不同修饰方法制备的蛋白质芯片进行对比研究。将Cy3标记羊抗鼠IgG固定在修饰后片基上,选择蛋白探针的固定率作为检测指标;将小鼠IgG作为探针固定在芯片上,靶蛋白为Cy3标记羊抗鼠IgG,通过生物芯片扫描仪检测反应后荧光强度,选择蛋白探针的反应性作为检测指标,探讨制备蛋白质芯片较佳的表面修饰方法。结果显示,戊二醛修饰玻片对蛋白固定较好,有较高的反应活性,检测限较宽,但背景噪声较高。     

Modeling the adsorption of aromatic compounds on the TiO2/SiO2 catalyst

The Grand Canonical Monte Carlo method was used to analyse the phenomenon of adsorption of aromatic compounds (i.e. phenol, toluene, benzoic acid and salicylic acid) on the surface of the titania-silica (TiO₂/SiO₂) catalyst. We found that different types of interactions play important roles in the adsorption of molecules having polar and non-polar groups. Moreover, we found that the interactions between sorbate molecules are strong, and are the cause of multilayer adsorption occurring in the investigated temperature and pressure range. Presented at: Modeling and Design of Molecular Materials, 10–15 September 2006, Wrocław, Poland.     

弱有机碱对光合磷酸化的影响

类囊体内部介质可被弱有机碱如吡啶、苯胺、咪唑缓冲,致使[H_(in)~ ] 减少,ΛpH幅度降低,光合磷酸化(PSP)反应被抑制,对苯二胺(p—PD)降低ΛpH,但显著促进PSP反应、在MV或PMS系统中均有此现象;在 MV DBMIB;MV DCMU或PMS DBMIB系统中,p—PDH_2重建ΛpH并恢复PSP反应活力。从p—PD(H_2)既具有弱有机碱性质,又可作为电子供体、氢递体,代替QH_2或PQH_2调节电子传递起转移质子的两种作用,解释了p—PD对ΛpH的抑制,却又促进PSP反应的现象。讨论了PSP反应对[H_(in)~ ],ΛpH幅度大小的依赖关系。     

响应面法探讨氯磺酸-吡啶法修饰条件对硫酸化当归多糖取代度的影响

用氯磺酸-吡啶法对当归多糖进行硫酸化修饰。用响应面法研究了修饰条件中反应温度(A)、反应时间(B)和氯磺酸-吡啶比例(C)三个因素对产物的硫酸基取代度的影响,建立回归模型,验证了其有效性,并分析了主效应和因素交互作用。结果表明,在A为65~95℃、B为60~180 m in、C为1:3~14.3范围内,三个因素与产物平均取代度(Y)的回归模型为Y=2.74+0.66×A+0.66×B+0.80×C+0.51×A×B-0.31×A×C-0.16×B×C-0.34×A2-0.23×B2-0.50×C2;F检验证明模型拟合较好,可以用于量化控制反应条件;三个因素对取代度的影响程度为CA=B,A和B之间存在极显著的交互作用。     

Correction to: Surface Plasmon Assisted Luminescence Enhancement of Ag NP/NWs-Doped SiO2-TiO2-ZrO2:Eu3+ Ternary System

Plasmonics - The original version of this article unfortunately contained a mistake.     

Plasmonic Behaviors of Two-Dimensional Ag/SiO2 Nanocomposite Gratings: Roles of Gap Diffraction and Localized Surface Plasmon Resonance Absorption

Two-dimensional Ag/SiO₂ nanocomposite gratings of 400 and 600 nm in grating constant are fabricated by etching the SiO₂ slabs implanted with Ag ions, and their plasmonic extinction, absorption, and reflection behaviors are investigated. Our results indicate that no scattering light fields can exist near the localized surface plasmon (LSP) resonance wavelength (about 405 nm) of Ag nanoparticles (NPs) due to the intense LSP resonance absorption. Especially, when the gaps between nanocomposite veins have a width close in value to the LSP resonance wavelength of Ag NPs, the local light fields in the grating plane can be slightly enhanced due to an in-phase addition of the incident light fields and the diffractive light fields induced by the gap diffraction, leading to a slight red shift of LSP resonance mode of Ag NPs. Moreover, in the LSP resonance absorption region, although the grating diffraction can still occur, the diffractive light fields are extremely weak, and thus, the local light fields in the grating plane cannot be modified by coherently adding these extremely weak diffractive light fields to the incident light fields. As a result, the LSP resonance mode of Ag NPs will keep its position unchanged even though the grating constant is set to make the first grating order rightly change from evanescent to radiative character.

     

Modification of the Micro Arc-oxidized Ti Surface for Implant Applications

Surface treatments applied to titanium and its alloys for implant applications are important for the development of bio properties.In this study,first an oxide layer was formed on the surface of the titanium plate by micro arc oxidation,and then both calcium phosphate and calcium phosphate/chitosan accumulation were performed for different samples by the sol-gel method.FE-SEM/EDS examinations,XRD,FTIR and thermal analysis were performed for these micro arc-oxidized,cal-cium phosphate-coated and calcium phosphate/chitosan-coated surfaces.The surface roughnesses for these surfaces were measured between 10 μm and 100 μm,suitable for bone development on the surface.The effect of chitosan addition on the calcium phosphate-coated surface on apatite formation ability and antibacterial properties was investigated.Although the addition of chitosan slows down the formation of apatite,it ensured that the coating had antibacterial properties.The calcium phosphate/chitosan biocomposite obtained can be recommended for dental and orthopedic implants.     

Ni3+‐Induced Formation of Active NiOOH on the Spinel Ni–Co Oxide Surface for Efficient Oxygen Evolution Reaction

Efficient and earth abundant electrocatalysts for high‐performance oxygen evolution reaction (OER) are essential for the development of sustainable energy conversion technologies. Here, a new hierarchical Ni–Co oxide nanostructure, composed of small secondary nanosheets grown on primary nanosheet arrays, is synthesized via a topotactic transformation of Ni–Co layered double hydroxide. The Ni³⁺‐rich surface benefits the formation of NiOOH, which is the main redox site as revealed via in situ X‐ray absorption near edge structure and extended X‐ray absorption fine structure spectroscopy. The Ni–Co oxide hierarchical nanosheets (NCO–HNSs) deliver a stable current density of 10 mA cm^?2 at an overpotential of ≈0.34 V for OER with a Tafel slope of as low as 51 mV dec^?1 in alkaline media. The improvement in the OER activity can be ascribed to the synergy of large surface area offered by the 3D hierarchical nanostructure and the facile formation of NiOOH as the main active sites on the surface of NCO–HNSs to decrease the overpotential and facilitate the catalytic reaction.     

Detection of protein-protein interactions on SiO2/Si surfaces by spectroscopic ellipsometry

We have applied spectroscopic ellipsometry to sensitive detection of specific protein-protein interactions on SiO2/Si substrates. First, the change of ellipticity of the reflected polarized light (600-1100 nm) was correlated with the thickness of the protein layer immobilized on SiO2/Si surfaces by measuring monomeric (myoglobin) and homotetrameric (hemoglobin) proteins with a similar monomer size. Protein-protein interactions were then measured with the antigen/antibody and cell-surface receptor/ligand systems; in each system either of the two proteins was bound to SiO2/Si substrates. Consequently, significant ellipticity changes were observed only for the cases where the interactions were specific. A specific antibody binding was also detectable with an antigen displayed on the surface of bacteriophage particles. These results show the usefulness of spectroscopic ellipsometry for sensitive detection of protein-protein interactions and its applicability to a detection method for the protein-based biochips to be developed in the future.     

弱磁场对骨骼肌肌质网钙调控作用的研究

目的：探讨弱磁场对提取的骨骼肌肌质网系（SR）Ca（2＋）转运、钙泵（Ca（2＋）-Mg（2＋）-ATPase）及钙释放通道（RyR）活性的影响,从分子水平和细胞信号系统的角度来解释生物电磁效应。方法：利用动态光谱法检测0.4 mT弱磁场辐照过的SR Ca（2＋）转运、Ca（2＋）-ATPase活性,还原型辅酶（NADH）的氧化初速率和超氧（O_2-）产率,以及用同位素标记方法检测[3H]-Ryanodine与RyR的平衡结合度。结果：弱磁场辐照引起SR的Ca（2＋）摄取功能和Ca（2＋）-ATPase的活性明显下降,Ca（2＋）释放和[3H]-Ryanodine平衡结合度上升,同时上调了NADH的氧化初速率和O_2-的产率。结论：提示0.4 mT弱磁场辐照30 min对SR Ca（2＋）-ATPase活性有明显抑制,对RyR有一定的激活效果。     

Effect of Reaction Conditions on the Characterization of Plasmon-Driven Surface Catalytic Reduction Reaction for Para-nitroaniline in a Liquid Condition

Plasmon-driven–coupling reactions through nitro reduction or amino oxidation have been widely reported in the literature. This article studies the functional groups, reaction environment, and the effect of the molecular probe concentration on the coupling reaction using a surface-enhanced Raman spectroscopy (SERS) detection technique. First, we illustrate a sequence of nitro reduction and amino oxidation reactions under the same reaction conditions. Secondly, the relationships between the characterization phenomenon and the variables were studied by adjusting both the pH of the solution, the laser exposure time, and the concentration of the molecular probe in the reaction. We also performed the SERS detection on the product solution in liquid environments, indicating that p,p′-dimercaptoazobenzene (DAAB) is stable in the reaction system. There was no reverse reaction present, and no further polymerization was performed. This study demonstrates that the chemical reaction process is stable in plasmon-catalyzed reactions and serves as a starting point for future fluorescent probe studies with pH-regulated reactions.

     

Ultrathin Bilayer of Graphite/SiO2 as Solid Interface for Reviving Li Metal Anode

Lithium metal anodes are expected to drive practical applications that require high energy‐density storage. However, the direct use of metallic lithium causes safety concerns, low rate capabilities, and poor cycling performance due to unstable solid electrolyte interphase (SEI) and undesired lithium dendrite growth. To address these issues, a radio frequency sputtered graphite‐SiO₂ ultrathin bilayer on a Li metal chips is demonstrated, for the first time, as an effective SEI layer. This leads to a dendrite free uniform Li deposition to achieve a stable voltage profile and outstanding long hours plating/stripping compared to the bare Li. Compared to a bare Li anode, the graphite‐SiO₂ bilayer modified Li anode coupled with lithium nickel cobalt manganese oxide cathode (NMC111) and lithium titanate shows improved capacity retention, higher capacity at higher rates, longer cycling stability, and lower voltage hysteresis. Graphite acts as an electrical bridge between the plated Li and Li electrode, which lowers the impedance and buffers the volume expansion during Li plating/stripping. Adding an ultrathin SiO₂ layer facilitates Li‐ion diffusion and lithiation/delithiation, provides higher electrolyte affinity, higher chemical stability, and higher Young's modulus to suppress the Li dendrite growth.     

SiO2/SnO2/Sb2O5 microporous ceramic material for immobilization of Meldola's blue: application as an electrochemical sensor for NADH

The mixed oxide SiO(2)/SnO(2), containing 25 wt% of SnO(2), determined by X-ray fluorescence, was prepared by the sol-gel method and the porous matrix obtained was then grafted with Sb (V), resulting the solid designated as (SiSnSb). XPS indicated 0.7% of Sb atoms on the surface. Sb grafted on the surface contains Br?nsted acid centers (SbOH groups) that can immobilize Meldola's blue (MB(+)) cationic dye onto the surface by an ion exchange reaction, resulting the solid designated as (SiSnSb/MB). In the present case a surface concentration of MB(+)=2.5×10(-11) mol cm(2) on the surface was obtained. A homogeneous mixture of the SiSnSb/MB with ultra pure graphite (99.99%) was pressed in disk format and used to fabricate a working electrode that displayed an excellent specific electrocatalytic response to NADH oxidation, with a formal potential of -0.05 V at pH 7.3. The electrochemical properties of the resulting electrode were investigated thoroughly with cyclic voltammetric and chronoamperometry techniques. The proposed sensor showed a good linear response range for NADH concentrations between 8×10(-5) and 9.0×10(-4) mol L(-1), with a detection limit of 1.5×10(-7) mol L(-1). The presence of dopamine and ascorbic acid did not show any interference in the detection of NADH on this modified electrode surface.     

The Effect of Gold Nanoparticle Surface Modification with Polyethylene Glycol on the Absorbed Dose Distribution upon Irradiation with 137Cs and 60Co Photons

Biophysics - Abstract—Modification of the surface of gold nanoparticles with polyethylene glycol (PEG) is widely used to investigate radiosensitization in vivo. This modification may lead to...     

Photoconductivity of Silver Nanoparticle Ensembles on Quartz Glass (SiO2) Supports Assisted by Localized Surface Plasmon Excitations

We have studied the conductivity and photoconductivity in silver nanoparticle ensembles on quartz glass substrates. We observed a significant increase of the photoconductivity if the localized surface plasmon resonance in the metal nanoparticles was excited. A detailed analysis of the temperature dependence of the conductivity as well as dependences of the conductivity and photoconductivity on the amount of deposited metal led to the mechanism of the charge transfer in these structures. We found that the primary role in this mechanism is due to defects in the quartz glass structure which act as traps for electrons.     

Effects of TiO2 and Co3O4 Nanoparticles on Circulating Angiogenic Cells

Background and Aim

Sparse evidence suggests a possible link between exposure to airborne nanoparticles (NPs) and cardiovascular (CV) risk, perhaps through mechanisms involving oxidative stress and inflammation. We assessed the effects of TiO₂ and Co₃O₄ NPs in human circulating angiogenic cells (CACs), which take part in vascular endothelium repair/replacement.

Methods

CACs were isolated from healthy donors’ buffy coats after culturing lymphomonocytes on fibronectin-coated dishes in endothelial medium for 7 days. CACs were pre-incubated with increasing concentration of TiO₂ and Co₃O₄ (from 1 to 100 μg/ml) to test the effects of NP – characterized by Transmission Electron Microscopy – on CAC viability, apoptosis (caspase 3/7 activation), function (fibronectin adhesion assay), oxidative stress and inflammatory cytokine gene expression.

Results

Neither oxidative stress nor cell death were associated with exposure to TiO₂ NP (except at the highest concentration tested), which, however, induced a higher pro-inflammatory effect compared to Co₃O₄ NPs (p<0.01). Exposure to Co₃O₄ NPs significantly reduced cell viability (p<0.01) and increased caspase activity (p<0.01), lipid peroxidation end-products (p<0.05) and pro-inflammatory cytokine gene expression (p<0.05 or lower). Notably, CAC functional activity was impaired after exposure to both TiO₂ (p<0.05 or lower) and Co₃O₄ (p<0.01) NPs.

Conclusions

In vitro exposure to TiO₂ and Co₃O₄ NPs exerts detrimental effects on CAC viability and function, possibly mediated by accelerated apoptosis, increased oxidant stress (Co₃O₄ NPs only) and enhancement of inflammatory pathways (both TiO₂ and Co₃O₄ NPs). Such adverse effects may be relevant for a potential role of exposure to TiO₂ and Co₃O₄ NPs in enhancing CV risk in humans.     

A highly sensitive fluorescence sensor based on lucigenin/chitosan/SiO2 composite nanoparticles for microRNA detection using magnetic separation

In this paper, a convenient reverse‐phase microemulsion method for the synthesis of SiO₂ nanoparticles (NPs) by simply introducing the chitosan and fluorescent dye of lucigenin during the formation reaction of SiO₂ NPs was proposed. Addition of chitosan can make the SiO₂ NPs porous, and increases lucigenin molecule incorporation into chitosan/SiO₂ NPs nanopores based on electrostatic interaction and supermolecular forces. Therefore, fluorescence quantum yield of the lucigenin/chitosan/SiO₂ composite nanoparticles was increased by introduction of chitosan and compared with lucigenin/SiO₂ NPs without chitosan. Because the number of negative charges carried when using single‐stranded DNA (ssDNA) was different from that of double‐stranded DNA (dsDNA), the numbers of lucigenin/chitosan/SiO₂ composite nanoparticles with positive charge adsorbed using ssDNA or dsDNA were different. Consequently, fluorescence intensity caused using ssDNA or dsDNA/miRNA was clearly discriminative. With increase in target DNA/miRNA concentration, the difference in fluorescence intensity also increased, resulting in a good linear relationship between fluorescence intensity sensitizing value and target miRNA concentrations. Therefore, a new fluorescence analysis method for direct detection of let‐7a in human gastric cancer cell samples without enzyme, label free and no immobilization was established using lucigenin/chitosan/SiO₂ composite nanoparticles as a DNA hybrid indicator. The proposed method had high sensitivity and selectivity, low cost and the detection limit was 10 fM (S/N = 3).