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The Thermochromatium tepidium PYP domain (Tt PYP), containing a gene for a chimeric photoactive yellow protein/bacteriophytochrome/diguanylate cyclase (Ppd), is produced in Escherichia coli. It is concluded that Tt PYP is unique among the PYPs studied to date in that it has a photocycle initiated from a dark-adapted state with a protonated chromophore at physiological pH.

Spectroscopic and computational studies of the azide-adduct of manganese superoxide dismutase have been presented. The results highlight the role that second-sphere residues, especially Tyr34, plays in tuning substrate (analog)/metal ion interactions.

The relation between thermochromism in polythiophenes and the internal rotation was studied by density functional theory (DFT). It was found that the internal rotation alone was not sufficient to explain the mechanism of thermochromism.

A highly lipophilic polyion complex [Pt[(en).sub.2]][Pt[Cl.sub.2][(en).sub.2]][(1).sub.4] (en, 1,2-diaminoethane) is prepared from one-dimensional mixed valence [Pt.sup.II]/[Pt.sup.IV] complex and newly designed chiral amphiphile 1. The powdery sample showed purple color, which is a result of the mixed valence absorption of the linear chlorobridged complex [([Pt.sup.II]-Cl-[Pt.sup.IV]-Cl-).sub.n]. When the lipid complex is dispersed in dichloromethane, purple-colored dispersion is obtained at 0 [degrees] C, whereas the color disappears after heating the solution to 21 [degrees] C. The observed thermochromism is reversible with respect to the temperature changes and is ascribed to the reversible dissociation and reassembly of the self-assembling inorganic wires. Casting of the 0 [degrees] C-purple dispersion on solid substrates affords honeycomb nanostructures in addition to the nanowires with the width of about 20 nm. The honeycomb patterns seem to be templated by the condensed water droplets that are formed and aligned on the rapidly evaporating dichloromethane solution. On the other hand, more regular honeycomb structures are exclusively obtained by casting the 21 [degrees] C-colorless solution. These observations indicate that the ordered honeycomb structures are obtainable on solid surfaces by the self-assembly of molecularly dispersed components [Pt[(en).sub.2]][(1).sub.2] and trans[Pt[Cl.sub.2][(en).sub.2]][(1).sub.2]. Very interestingly, formation of double-layered honeycomb nanostructure is observed by scanning electron microscopy. The unit hexagons and pillars of the honeycombs are made of nanowires that are hierarchically assembled from the lipid-packaged [Pt.sup.II]/[Pt.sup.IV] complexes. The surface self-organization of lipophilic inorganic complexes has a potential to fabricate novel nanoarchitectures with conjugated electronic structures.

Hue-based hysteresis of thermochromic liquid crystal temperature measurement has been studied. Detailed calibration data for microencapsulated thermochromic liquid crystal is given. Significant hysteresis is found in the hue-calibration data.

A technique was developed for the in situ assessment of the vertical nitrogen flux caused by the diel vertical migration of zooplankton. It is demonstrated that given a high inter-individual variation in body nitrogen content and low sample size, detection of the predicted diel change may be obscured. The technique can be used to measure the vertical carbon fluxes caused by normal diel vertical migration in both omnivorous and carnivorous species.

The single crystal layered compound [K.sub.2]Na[[Ag[(CN).sub.2]].sub.3] is observed to show remarkable luminescence changes involving optical memory and luminescence thermochromic changes. The unprecedented occurrence of both novel phenomena in the compound is found to be related to reversible photophysical changes instead of irreversible photochemical changes.

The mixed-valence compound (NH3 5 Ru-NC-Fe CN 5)Na was synthesized and its intervalence thermochromism was investigated. A transient thermochromic bleaching and recovery was expected in view of the intervalence absorbance measurements made on the high-energy side of the intervalence band and the negative sign of dE(sub op)/dT. It follows that a sign reversal should result fron measurements on the low energy side. These indicate that the driving force is temperature-dependent and that it is most negative when the temperature is at its lowest.

Calorimetry, reflectivity and magnetism techniques were used for analyzing the transition temperature modifications with tungsten substitution. Findings reveal a significant increase in the temperature transition in a parallel way for the heating and cooling mode on substitution of molybdenum for tungsten.

Topochemically polymerized sodium 10, 12-pentacosadiynoate microcrystals show an irreversible red-to-blue chromatic transition accompanied by a distinct structural evolution upon initial thermal treatment, and show a subsequent completely reversible blue-to-red chromatic transition upon further thermal stimuli. Quantum mechanical geometry optimization was employed to explain the lattice dimensional change during the irreversible red-to-blue chromatic transition of the metastable polydiacetylenic crystals.

The aspects of inorganic synthesis are covered and an introduction is given to three of the most widely used methods for forming thin films of material, chemical vapor deposition, the sol-gel process, and physical vapor deposition. This will help the educator to set up lectures on thin-film deposition and in application of new materials.

UV/vis spectra of thermochromic semibullvalenes and barbaralanes, which undergo rapid degenerate Cope rearrangements, display temperature-dependent shoulders or absorption maxima at the low-energy side of their strong UV bands. The long-wavelength absorptions are ascribed to Franck-Condon transitions from delocalized structures.

Supramolecular of metalloporphyrin is demonstrated by using a zinc complex of (3-pyridyl) porphyrin with an alkynyl sidearm (3-pyridyl group). A novel molecular design concept for supramolecular is discussed.

The reaction center (RC) of photosynthetic bacteria is a membrane protein complex that promotes a light-induced charge separation during the primary process of photosynthesis. In the photosynthetic electron transfer chain, the soluble electron carrier proteins transport electrons to the RC and reduce the photo-oxidized special-pair of bacteriochlorophyll. The high-potential iron-sulfur protein (HiPIP) is known to serve as an electron donor to the RC in some species, where the c-type cytochrome subunit, the peripheral subunit of the RC, directly accepts electrons from the HiPIP. Here we report the crystal structures of the RC and the HiPIP from Thermochromatium (Tch.) tepidum, at 2.2-[Angstrom] and 1.5-[Angstrom] resolution, respectively. Tch. tepidum can grow at the highest temperature of all known purple bacteria, and the Tch. tepidum RC shows some degree of stability to high temperature. Comparison with the RCs of mesophiles, such as Blastochloris viridis, has shown that the Tch. tepidum RC possesses more Arg residues at the membrane surface, which might contribute to the stability of this membrane protein. The RC and the HiPIP both possess hydrophobic patches on their respective surfaces, and the HiPIP is expected to interact with the cytochrome subunit by hydrophobic interactions near the heme-1, the most distal heme to the special-pair.

In the early days of superconductivity, researchers expected that superconductors, by analogy with good metals, would be particularly good reflectors of high-frequency radiation. However, no changes in reflectivity in the [...]

Paramagnetic nuclear magnetic resonance data provide first evidence of a room temperature thermochromism for the reduced form of the tetrameric iron superoxide dismutase from the archaebacterium Methanobacterium thermoautotrophicum. Two sets of signals corresponding to two different species are identified from the relative temperature dependent intensities. The temperature dependence of the equilibrium constant K between the two species demonstrates a thermal two-state transition.

Research was conducted to examine the crystal structure change for the thermochromy of N-salicylideneanilines using X-ray diffraction method. It was observed that the crystal structures changed with variation in temperature. It is concluded that there is an equilibrium between the OH and NH forms in crystals and that the population of the NH form increases with lowering the temperature.