162 research outputs found
A FDR-preserving field theory for interacting Brownian particles: one-loop theory and MCT
We develop a field theoretical treatment of a model of interacting Brownian
particles. We pay particular attention to the requirement of the time reversal
invariance and the fluctuation-dissipation relationship (FDR). The method used
is a modified version of the auxiliary field method due originally to
Andreanov, Biroli and Lefevre [J. Stat. Mech. P07008 (2006)]. We recover the
correct diffusion law when the interaction is dropped as well as the standard
mode coupling equation in the one-loop order calculation for interacting
Brownian particle systems.Comment: 66 pages, 8 figures, submitted to J. Stat. Mec
Formate-Free Metal-Organic Decomposition Inks of Copper Particles and Self-Reductive Copper Complex for the Fabrication of Conductive Copper Films
Metal-organic decomposition (MOD) inks have been developed for printed electronics applications. Cu-based MOD inks prevent the oxidation of the metal during storage, as the Cu is already present in an oxidized form (i.e. a salt). However, usually hazardous formates such as Cu (II) formate have to be used as the copper salt in order to ensure thermal decomposition and self-reduction of the metal salt at moderate temperatures (less than 150°C). In this study, a formate-free hybrid ink containing copper particles and a Cu/1-amino-2-propanol (AmIP)/acetate complex was developed for the fabrication of conductive copper films on flexible polymer substrates at low sintering temperatures. A hybrid ink with a weight ratio of 3:1copper particles to MOD ink produced a conductive copper film with close-packed copper particles and a low resistance of 7.3—10-5Ω cm after sintering at a temperature of 180°C for 60 min under a N2 gas flow. Good oxidation resistance of the copper films was observed after exposure to air at 23 °C for two months
Mouse Embryonic Stem Cells Inhibit Murine Cytomegalovirus Infection through a Multi-Step Process
In humans, cytomegalovirus (CMV) is the most significant infectious cause of intrauterine infections that cause congenital anomalies of the central nervous system. Currently, it is not known how this process is affected by the timing of infection and the susceptibility of early-gestational-period cells. Embryonic stem (ES) cells are more resistant to CMV than most other cell types, although the mechanism responsible for this resistance is not well understood. Using a plaque assay and evaluation of immediate-early 1 mRNA and protein expression, we found that mouse ES cells were resistant to murine CMV (MCMV) at the point of transcription. In ES cells infected with MCMV, treatment with forskolin and trichostatin A did not confer full permissiveness to MCMV. In ES cultures infected with elongation factor-1α (EF-1α) promoter-green fluorescent protein (GFP) recombinant MCMV at a multiplicity of infection of 10, less than 5% of cells were GFP-positive, despite the fact that ES cells have relatively high EF-1α promoter activity. Quantitative PCR analysis of the MCMV genome showed that ES cells allow approximately 20-fold less MCMV DNA to enter the nucleus than mouse embryonic fibroblasts (MEFs) do, and that this inhibition occurs in a multi-step manner. In situ hybridization revealed that ES cell nuclei have significantly less MCMV DNA than MEF nuclei. This appears to be facilitated by the fact that ES cells express less heparan sulfate, β1 integrin, and vimentin, and have fewer nuclear pores, than MEF. This may reduce the ability of MCMV to attach to and enter through the cellular membrane, translocate to the nucleus, and cross the nuclear membrane in pluripotent stem cells (ES/induced pluripotent stem cells). The results presented here provide perspective on the relationship between CMV susceptibility and cell differentiation
Antibacterial and cytotoxic effects of photoexcited Au clusters via blue high-power or white low-power light emitting diode irradiation
The development of photosensitizers and light sources has enabled the use of antimicrobial photodynamic therapy (aPDT) in various dental therapies. In the present study, we compared the antibacterial and cytotoxic effects of Au clusters photoexcited by blue and white LED irradiation. We fabricated novel photosensitizers, captopril-protected gold (Capt-Au) clusters and lysozyme-stabilized gold (Lyz-Au) clusters, for aPDT. Au clusters were then photoexcited by two kinds of light sources, blue high-power and white low-power light-emitting diodes (LEDs). Since white LED contains a wide spectrum of light (400–750 nm), white LED would be relevant for aPDT even if using a low-power source. The turbidity and viability of Streptococcus mutans were assessed following application of Capt-Au clusters (500 μg/mL) or Lyz-Au clusters (1,000 μg/mL) photoexcited by a blue high-power LED (1,000 mW/cm2) or white low-power LED (80 mW/cm2). In addition, the cytotoxicity of Au clusters and LED irradiation was evaluated in NIH3T3 and MC3T3-E1 cells. Au clusters photoexcited by the white low-power LED equally decreased the turbidity and viability of S. mutans compared with blue high-power LED. However, Au clusters photoexcited by white LED irradiation caused decreased cytotoxicity in mammalian cells compared with those photoexcited by blue LED irradiation. In conclusion, white LEDs possess biosafe properties for aPDT using Au clusters
Use of thermally annealed multilayer gold nanoparticle films in combination analysis of localized surface plasmon resonance sensing and MALDI mass spectrometry
A self-assembled film of gold nanoparticles (AuNPs) with a raspberry-like morphology was prepared on a glass plate by the layer-by-layer thermal annealing of multilayer films of AuNPs. It was possible to control the morphology of the obtained films of AuNPs by changing the annealing temperature,duration of annealing, and number of layers. On investigating the plasmonic properties of these films,we found that AuNP films with a raspberry-like morphology yielded the highest refractive index unit,which is a critical parameter in localized surface plasmon resonance (LSPR) sensing, as compared to other types of AuNP films. Self-assembled AuNP films with a raspberry-like morphology were subsequently functionalized with 11-mercaptoundecanoic acid (MUA) to enable the binding of lysozyme to the MUA-modified Au surface. The superior limit of detection for the LSPR sensing of lysozyme in a buffer solution was found to be in the picomolar range (~10(12) M). The high sensitivity observed in the region was attributed to the raspberry-like morphology, where the AuNPs were packed closely together, and the electromagnetic field confinement was most intense (i.e., at hot spots). The MUA-modified, self-assembled AuNP films with a raspberry-like morphology were finally used in the combination analysis of LSPR sensing and matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) for the selective detection and identification of lysozyme in human serum
Microwave-assisted polyol synthesis of copper nanocrystals without using additional protective agents
We report the synthesis of 2 nm copper nanocrystals (Cu NCs)via a microwave-assisted polyol method without using additional protective and reducing agents. The Cu NCs are oxidation resistant and exhibit photoluminescence and highly stableproperties in a colloidal dispersion
Surfactant-free solution synthesis of fluorescent platinum subnanoclusters
We have demonstrated the first surfactant-free synthesis of fluorescent Pt nanoclusters in N,N-dimethylformamide (DMF) solution. The Pt nanoclusters consist of 4 to 6 Pt atoms. They form highly stable dispersions in water, under both acidic (pH 2) and basic conditions (pH 12), and at ionic strengths of 1 M NaCl
DNAナノ構造体を用いたウイルスの単粒子捕獲と無毒化法の開発 : 平成24年度関西大学若手研究者育成経費研究成果報告書
本研究の⼀部は、平成24年度関⻄⼤学若⼿研究者育成経費において、研究課題「DNAナノ構造体を⽤いたウイルスの単粒⼦捕獲と無毒化法の開発」として研究費を受け、その成果を公表するものである
Attempt to Characterize Egyptian Painting Layers by GC/MS and Optical Method
Organic binding media and color materials used in Egyptian wall paintings were characterized using gas chromatograph-mass spectrometry (GC-MS). Fourier-transform infrared spectroscopy (FT-IR) and Raman spectroscopy. The small samples of the wall paintings were obtained from the debris in Funeral House (Egyptian House) in Tuna el-Gabal that was at the age of Persian or Ptolmaic Period. The aim of this study is to investigate a possibility of discrimination between Arabic gum and animal protein-based binders used in ancient Egypt and to recognize the use of mixtures of the two products. The GC-MS results showed that saturated fatty acid esters and the compound which seemed to be fatty acid glyceride were detected in the extract of the wall surface. Unsaturated aliphatic alcohols, esters, and the components with a steroid frame were observed from the direct probe method of EI-MS. In FT-IR, the absorption bands of calcium hydroxide in the red part of the painting and inorganic oxide in the black part were observed. In Raman spectra, it was supposed that amorphous carbon was used for color material of the black district and cinnabar (HgS) was for that of the red part. In addition, the color materials with fluorescence were detected in the red and blue part of surface
Characterization of Organic Binding Media Used in Egyptian Painting Layers by GC/MS
Organic binding media used in Egyptian wall paintings was characterized using gas chromatograph-mass spectrometry (GC-MS). Samples of the wall paintings were obtained from the dubris in the mastaba of Idout, Saqqara in Egypt. The aim of this study is to investigate the possibility of discrimination between arabic gum and animal protein-based binders used in ancient Egypt. In this present study, three methods of sample preparation and injection in GC-MS (double-shot injection, reaction pyrolysis and liquid-injection) were tested for the most sensitive detection of the organic binding media. The GC-MS results showed that the double-shot injection and liquid-injection methods detected no natural products, but the reaction pyrolysis method could detect saturated fatty-acid esters and fatty-acid glyceride-like compounds. However, these organic compounds found at the Idout wall painting are almost consistent with the previously reported compounds that were detected from the wall painting samples obtained from the Funeral House in Tuna el-Gabal. In conclusion, the organic binding media could not be discriminated again.ガスクロマトグラフィー質量分析(GC-MS)の3種類の測定手法、ダブルショット法、反応熱分解法および液体注入法を用いて、エジプト壁画に使用されている接着剤などの有機化合物の分析を行った。試料はサッカラのイドゥートの埋葬室から得られた壁画の小片である。ダブルショット法、液体注入法を用いたGC-MS測定では、天然物由来の有機化合物を検出することができなかった。反応熱分解法を用いて壁画表面をGC-MSで分析した結果、飽和脂肪酸エステル類が強く、他にも脂肪酸グリセリド様と思われる化合物を検出した。その結果は、前回測定したツナ・エル・ガバル遺跡の壁画小片から検出した有機物とほぼ同じ化合物群であり、今回も壁画に使用されている接着材の成分を識別することはできなかった。3種類の分析方法の中で反応熱分解法が、有機化合物に対してもっとも感度が高かった
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