The Still-Wittig Rearrangement in the Preparation of a Synthetically Useful 4C-Hydroxymethyl-hex-2-eno-pyranoside

The Still-Wittig rearrangement of the stannyl-ether 9 is successfully carried out under optimal reaction conditions to give the 4C-hydroxymethy-hex-2-enopyranoside 10 in good yields (70–74%).     

Effect of styrene–acrylonitrile content on 0.5?M NaI/0.05?M I2 liquid electrolyte encapsulation for dye-sensitized solar cells

The effect of a gel polymer electrolyte (GPE) as the redox electrolyte used in dye-sensitized solar cells was studied. A GPE solution consisting of 0.5?M sodium iodide, 0.05?M iodine, and ethylene carbonate/propylene carbonate (1:1 w/w) binary solvents was mixed with increasing amounts of styrene–acrylonitrile (SAN). Bulk conductivity measurements show a decreasing trend from 4.54 to 0.83×10^?3?S?cm^?1 with increasing SAN content. The GPE exhibits Newtonian-like behavior and its viscosity increases from 0.041 to 1.093?Pa?s with increasing SAN content. A balance between conductivity (1.3?×?10^?3?S?cm^?1) and viscosity (1.4?Pa?s) is observed at 19?wt.% SAN. Fourier transform infrared spectroscopy detects elevated ring torsion at 706?cm^?1 upon the addition of SAN into the liquid electrolyte. This indicates that SAN does not bond with the liquid electrolyte. Finally, the potential stability window of 19?wt.% SAN, which ranges from ?1.68 to 1.38?V, proves its applicability in solar cells.     

Readily Accessible and Predictable Naphthalene‐Based Two‐Photon Fluorophore with Full Visible‐Color Coverage

Herein we report 22 acedan‐derived, two‐photon fluorophores with synthetic feasibility and full coverage of visible wavelength emission. The emission wavelengths were predicted by computational analysis, which enabled us to visualize multicolor images by two‐photon excitation with single wavelength, and to design a turn‐on, two‐photon fluorescence sensor for endogenous H₂O₂ in Raw 264.7 macrophage and rat brain hippocampus ex vivo.     

Lithography potentials of UV-nanoimprint

In the past decade nanoimprint has been developed to a serious alternative for next generation lithography (NGL). In this work, the most recent developments of UV-nanoimprint Lithography (UV-NIL) with special emphasis to the work accomplished at AMO and the IHT-RWTH Aachen are reviewed and functional applications demonstrated. Further the potentials of various UV-NIL concepts are evaluated and possible interests in certain application areas are discussed.     

Blood analysis by Raman spectroscopy

Concentrations of multiple analytes were simultaneously measured in whole blood with clinical accuracy, without sample processing, using near-infrared Raman spectroscopy. Spectra were acquired with an instrument employing nonimaging optics, designed using Monte Carlo simulations of the influence of light-scattering-absorbing blood cells on the excitation and emission of Raman light in turbid medium. Raman spectra were collected from whole blood drawn from 31 individuals. Quantitative predictions of glucose, urea, total protein, albumin, triglycerides, hematocrit, and hemoglobin were made by means of partial least-squares (PLS) analysis with clinically relevant precision (r(2) values >0.93). The similarity of the features of the PLS calibration spectra to those of the respective analyte spectra illustrates that the predictions are based on molecular information carried by the Raman light. This demonstrates the feasibility of using Raman spectroscopy for quantitative measurements of biomolecular contents in highly light-scattering and absorbing media.     

13C NMR study of alcohols complexed with nitroxide radical

The contact shifts of carbon nuclei in 8 alcohols complexed with 2,2,6,6-tetramethylpiperidine nitroxide radical were determined from the ¹³C NMR spectra and explained by hydrogen bonding and collision interactions.     

Two-phase partition chromatography using soybean oil eliminates pesticide residues in aqueous ginseng extract

This study was carried out to develop a cost-, labor- and efficiency-effective elimination method of pesticide residues in ginseng extract. A two-phase partition method between soybean oil and distilled water or aqueous ginseng extract was employed for the elimination of pesticide residues. Content of the pesticides was determined by gas chromatography with electron capture or nitrogen phosphorus detector. A total of 15 pesticides representing four categories (organochlorine, organophosphorus, carbamate, pyrethroid) were spiked (ca. 2 ppm) to 2 ml soybean oil in a test tube and the oil was mixed with 6 ml distilled water or 10% aqueous ginseng extract. The test tubes were then vortexed (2 min) and centrifuged at 3000 rpm for 15 min to separate the oil and aqueous layers. Each layer was harvested and subjected to quantitative analysis of pesticides. The average distribution ratio of the pesticides to the oil layer was 94.4 +/- 6.7% in the mixture of the oil and distilled water, and 105.5 +/- 6.6% in the mixture of the oil and ginseng extract. No significant qualitative and quantitative change of ginsenosides, the active ingredients of Panax ginseng, was observed in the ginseng extract before and after the oil treatment. These results suggest that two-phase partition chromatography between soybean oil and the aqueous phase is a cost-, labor- and efficiency-effective reliable method for the elimination of pesticide residues in ginseng extract.     

Rule for structures of open metal surfaces

We present a clear and simple rule for determining the relaxation sequences on open (stepped, vicinal, or high-Miller-index) metal surfaces. At the bulk-truncated configuration of a surface, a surface slab is defined where the coordination of atoms is reduced from the bulk. The rule predicts that the interlayer spacings within this slab contract, while the interlayer spacing between this slab and the substrate expands. By first-principles calculations, we show that this rule is obeyed on all open Cu surfaces with interlayer spacings down to about 0.5 A. We also illustrate a direct relation of the relaxation sequences to the charge redistribution on these surfaces, which is demonstrated to be driving the multilayer relaxations. The applicability of the rule can be extended to other fcc and bcc metals, including unreconstructed and missing-row surfaces.     

Direct observation of large electronic domains with memory effect in doped manganites

We use a spatially resolved, direct spectroscopic probe for electronic structure with an additional sensitivity to chemical compositions to investigate high-quality single crystal samples of La(1/4)Pr(3/8)Ca(3/8)MnO3, establishing the formation of distinct insulating domains embedded in the metallic host at low temperatures. These domains are found to be at least an order of magnitude larger in size compared to previous estimates and exhibit memory effects on temperature cycling in the absence of any perceptible chemical inhomogeneity, suggesting long-range strains as the probable origin.     

Effects of silicone acrylate on morphology, kinetics, and surface composition of photopolymerized acrylate mixtures

Films (ca. 150 microm thick) of twelve acrylate mixtures, which contained various proportions of hydrocarbon acrylates [mainly oligo(ethylene glycol) diacrylate, (OEGDA)] and small amounts of a silicone hexaacrylate (in proportion of 5% or less), were cured on a nickel substrate, and X-ray photoelectron spectroscopy analysis of the nickel-side surface compositions showed that for formulations with and without the silicone hexaacrylate, this surface was enriched with OEGDA and saturated (up to 50%) with the silicone hexaacrylate, respectively. The silicone hexaacrylate phase-separated and formed micelles which migrated to the resin-nickel interface. Silicone hexaacrylate, inherently less reactive, also significantly slowed the photopolymerization of the mixtures. The sequential homopolymerization of OEGDA and silicone hexaacrylate in a formulation was elicited using real-time Fourier transform infrared spectroscopy. The design-of-experiment approach was used to quantify the influence of the components on gelation time and the nickel-side surface composition as well as provide the statistical models to predict these two properties for new compositions.