Phenomena of Apparent Lightness Interpreted by the Recognized Visual Space of Illumination

Many experimental results have been reported which demonstrated deviation of the apparent lightness from the calculated lightness based on spectral reflectance, and these have caused debate among researchers as to the models to explain them. The judgement of lightness of objects that we see in the outside world is one of the most important tasks in our daily life. We proposed the recognized visual space of illumination, RVSI, as a three dimensional recognition constructed in the brain for the outside world, and showed that the apparent lightness was determined in relation to the size of the RVSI. In the present paper the concept was applied to various results of lightness experiments such as the White effect and simultaneous contrast, and based on the proposition that an observer first builds a three dimensional RVSI from a two dimensional pattern and the lightness of a test patch was judged in relation to the size of this RVSI, the results were then globally and nicely explained. A new demonstration of a pattern was proposed to give different apparent lightness for patches with the same physical lightness to strengthen the proposition. The importance of distinguishing between a test patch and a surrounding field was emphasized when one does a lightness experiment and interprets the results.     

Crystal water dynamics of guanosine dihydrate: analysis of atomic displacement parameters, time profile of hydrogen-bonding probability, and translocation of water by MD simulation

The dynamics of crystal water molecules of guanosine dihydrate are investigated in detail by molecular dynamics (MD) simulation. A 2 ns simulation is performed using a periodic boundary box composed of 4 x 5 x 8 crystallographic unit cells and using the particle-mesh Ewald method for calculation of electrostatic energy. The simulated average atomic positions and atomic displacement parameters are remarkably coincident with the experimental values determined by X-ray analysis, confirming the high accuracy of this simulation. The dynamics of crystal water are analyzed in terms of atomic displacement parameters, orientation vectors, order parameters, self-correlation functions of the orientation vectors, time profiles of hydrogen-bonding probability, and translocations. The simulation clarifies that the average structure is composed of various stable and transient structures of the molecules. The simulated guanosine crystal forms a layered structure, with four water sites per asymmetric unit, classified as either interlayer water or intralayer water. From a detailed analysis of the translocations of water molecules in the simulation, columns of intralayer water molecules along the c axis appear to represent a pathway for hydration and dehydration by a kind of molecular valve mechanism.     

Hybrid Organic-Inorganic Sol-Gel Materials Based on Epoxy-Amine Systems

Understanding the synthesis-structure-properties relationship of hybrid organic-inorganic materials is an important and fundamental task to develop a new generation of highly performing systems for the new needs of nanotechnologies. This issue is, also, important to improve the properties of hybrids when used in applications where nanoscale control is not a fundamental request. In this article, a short overview of epoxy amine sol-gel hybrids is reported. The synthesis of these materials has a large flexibility to allow the fabrication of a wide group of hybrids with different structures and properties, whose applications are ranging from non-linear optics to adhesive and protective coatings.     

Observation of CO(2) in Fourier transform infrared spectral measurements of living Acholeplasma laidlawii cells

In monitoring the time course of conformational disorder by Fourier transform infrared spectroscopy for intact Acholeplasma laidlawii cells grown at 37 degrees C on binary fatty acid mixtures containing oleic acid and for cells grown on pure palmitic acid, an absorption band at 2343 cm(-1) was observed. The band intensity was found to increase with time. This band was not observed in the spectra for isolated membranes. It is suggested that the 2343 cm(-1) band is due to CO(2) dissolved in water, most likely produced at the final point of fermentation of amino acid by this microorganism.     

Highly efficient separation of lithium chloride from seawater

A complexing reagent composed of two bipyridine moieties enabled the efficient separation of lithium chloride through liquid membrane from seawater, in which 0.005% lithium chloride is contained (more than 99% metal chlorides are NaCl, KCl, MgCl2, and CaCl2). That is, two separations by our liquid membrane changed the molar ratio of LiCl from 0.005% to 80%. The striking characteristic of this compound is that the lithium ion is separated efficiently from alkali and alkaline earth metal ions without the lipophilic anion. Thus this new membrane system contructed by us offers a low-energy, low-cost, and environmentally friendly method to enable the routine use of lithium chloride separation from seawater.     

Modeling the interplay between geometrical and energetic effects in protein folding

A theoretical framework is constructed with the aid of a free-energy functional method that is capable of describing the interplay between geometrical and energetic effects on protein folding. In this paper, we generalize a free-energy functional model based on polymer theory to make it more appropriate for comparison with protein folding simulations and experiments. This generalization is made by introducing cooperativity into the configurational entropy and the internal energy. Modifications to configurational entropy enable the model to account for the loop-loop interactions, a contribution neglected in the original model. Modifications to the internal energy introduce many-body corrections, which are needed to establish quantitative contact to simulations as well as experimental observations. To demonstrate the efficiency of the modified analytical model, we compare our results with C(alpha) structure-based (Go) model simulations of chymotrypsin inhibitor II and the SH3 domain of src.     

Palladium-catalyzed tetrakis(dimethylamino)ethylene-promoted reductive coupling of aryl halides

Tetrakis(dimethylamino)ethylene (TDAE)/cat. PdCl(2)(PhCN)(2)-promoted reductive coupling of aryl bromides having either electron-donating or electron-withdrawing groups on their para- and/or meta-position proceeded smoothly to afford the corresponding biaryls in good to excellent yields. Notably, TDAE is such a mild reductant that easily reducible groups, such as carbonyl and nitro groups, are tolerate. A similar reductive coupling of ortho-substituted aryl bromides did not occur at all. The proper choice of palladium catalysts is essential for the reductive coupling; thus, PdCl(2)(PhCN)(2), PdCl(2)(MeCN)(2), Pd(hfacac)(2), Pd(2)(dba)(3), PdCl(2), and Pd(OAc)(2) were used successively for this reaction, but phosphine-ligated palladium catalysts such as Pd(PPh(3))(4), PdCl(2)(PPh(3))(2), and Pd(dppp) did not promote the reaction. The reductive coupling did not occur with nickel catalysts such as NiBr(2), NiCl(2)(bpy), and Ni(acac)(2). The TDAE/cat. palladium-promoted reductive coupling of aryl halides having electron-withdrawing groups took place more efficiently than that of aryl halides substituted with electron-donating groups. A plausible mechanism of TDAE/cat. palladium-promoted reaction is discussed.     

Conjugate reduction of aryl acrylates with tributyltin hydride in the presence of magnesium bromide diethyl etherate

The conjugate reduction of aryl acrylates performed with tributyltin hydride in the presence of magnesium bromide diethyl etherate in dichloromethane gave the corresponding saturated esters in moderate to high yields. The reduction of α-methylene-γ-benzyloxycarboxylic acid esters proceeded syn-selectively, but α-methylene-β-oxycarboxylic acid esters afforded reductive elimination products under the reaction conditions.     

Occurrence of the cis-peptide in gaseous N-methylformamide as revealed by rotational structure in its infrared spectrum

In the 0.12 cm^?1 resolution infrared absorption spectrum of gaseous N-methylformamide, a progression of peaks with a spacing of about 2.6 cm^?1 has been found in the 610-540 cm^?1 region. This is assignable to a conformer with the CO and NH bonds cis to each other.