Function of membrane protein in silica nanopores: incorporation of photosynthetic light-harvesting protein LH2 into FSM

A high amount of functional membrane protein complex was introduced into a folded-sheet silica mesoporous material (FSM) that has nanometer-size pores of honeycomb-like hexagonal cylindrical structure inside. The photosynthetic light-harvesting complex LH2, which is a typical membrane protein, has a cylindrical structure of 7.3 nm diameter and contains 27 bacteriochlorophyll a and nine carotenoid molecules. The complex captures light energy in the anoxygenic thermophilic purple photosynthetic bacterium Thermochromatium tepidum. The amount of LH2 adsorbed to FSM was determined optically and by the adsorption isotherms of N2. The FSM compounds with internal pore diameters of 7.9 and 2.7 nm adsorbed LH2 at 1.11 and 0.24 mg/mg FSM, respectively, suggesting the high specific affinity of LH2 to the interior of the hydrophobic nanopores with a diameter of 7.9 nm. The LH2 adsorbed to FSM showed almost intact absorption bands of bacteriochlorophylls, and was fully active in the capture and transfer of excitation energy. The LH2 complex inside the FSM showed increased heat stability of the exciton-type absorption band of bacteriochlorophylls (B850), suggesting higher circular symmetry. The environment inside the hydrophobic silica nanopores can be a new matrix for the membrane proteins to reveal their functions. The silica-membrane protein adduct will be useful for the construction of new probes and reaction systems.     

Internal motions in a complex consisting of a rare gas atom and a C2v molecule: theoretical formulations and their applications to Fourier transform microwave spectra of Ne-dimethyl ether and Ar-dimethyl ether

The internal motion of the rare gas atom, i.e., the relative motion of the two constituents, in a complex shown in the title was discussed by paying special attention to its effect on the rotational motion of the complex in order to extract as much precise information on this motion as possible from the observed rotational spectra. We have set up two theoretical formulations. One is based on a coordinate axis system attached to the C2v molecule, but its origin is floating with the motion of the rare gas atom, while keeping the orientation parallel to the original C2v molecule-fixed coordinate system. The second approach starts with counting the number of equivalent potential minima, which are well separated from the others by high potential barriers, and then collects all permutation-inversion operations, which transform the system from one minimum to another, to set up a group appropriate for the complex. By using the symmetry properties thus derived, a phenomenological Hamiltonian is set up to fit the observed spectra. The two formulations result in alike rotational energy matrices, and we have applied them to analyze the internal motions in the two complexes of present concern: neon-dimethyl ether (Ne-DME) and argon-dimethyl ether (Ar-DME). Some of the transitions observed by the present study exhibited additional splittings, which were interpreted as due to an internal rotation of the methyl groups in DME and were analyzed by the second formulation. For Ar-DME the splittings appeared only in high-K transitions, yielding the V3 potential barrier to be 778(1) cm(-1), whereas those observed for Ne-DME were ascribed to the effects of the CH3 internal rotation on the inversion splitting.     

Solving stochastic mathematical programs with equilibrium constraints via approximation and smoothing implicit programming with penalization

In this paper, we consider the stochastic mathematical programs with linear complementarity constraints, which include two kinds of models called here-and-now and lower-level wait-and-see problems. We present a combined smoothing implicit programming and penalty method for the problems with a finite sample space. Then, we suggest a quasi-Monte Carlo approximation method for solving a problem with continuous random variables. A comprehensive convergence theory is included as well. We further report numerical results with the so-called picnic vender decision problem.     

A Supramolecularly Assisted Transformation of Block‐Copolymer Micelles into Nanotubes

Once around the block : Incorporation of a rigid hydrogen‐bonding benzamide unit, placed at the interface between two polymer blocks, in poly(ethylene glycol) (PEG)–(thio)urea–poly(L ‐lactide) (PLLA) block copolymers transforms the morphology of the block copolymers, from spherical micelles, as formed by PEG‐PLLA diblock copolymers, into nanotubes in solution.

     

Semidefinite complementarity reformulation for robust Nash equilibrium problems with Euclidean uncertainty sets

Consider the N-person non-cooperative game in which each player’s cost function and the opponents’ strategies are uncertain. For such an incomplete information game, the new solution concept called a robust Nash equilibrium has attracted much attention over the past several years. The robust Nash equilibrium results from each player’s decision-making based on the robust optimization policy. In this paper, we focus on the robust Nash equilibrium problem in which each player’s cost function is quadratic, and the uncertainty sets for the opponents’ strategies and the cost matrices are represented by means of Euclidean and Frobenius norms, respectively. Then, we show that the robust Nash equilibrium problem can be reformulated as a semidefinite complementarity problem (SDCP), by utilizing the semidefinite programming (SDP) reformulation technique in robust optimization. We also give some numerical example to illustrate the behavior of robust Nash equilibria.     

A study of chiral recognition for NBD-derivatives on a Pirkle-type chiral stationary phase.

A chiral stationary phase (CSP 1) derived from an (S)-N-3,5-dinitrobenzoyl-1-naphthylglycine showed excellent enantiomeric separation for amino acid derivatives with a fluorogenic reagent, 4-fluoro-7-nitro-2,1,3-benzoxadiazole (NBD-F), in high-performance liquid chromatography (HPLC). We compared elution profiles (separation factor and elution order) of NBD-amino acids and their analogs on HPLC, to determine the diastereomeric complex between the chiral moiety of CSP 1 and NBD-amino acid, which is responsible for the chiral recognition. (1)H-NMR studies of a mixture of model compound of CSP 1 and NBD-Ala suggest that the diastereomeric complex is composed of two hydrogen bonding sites at the amino proton and oxygen atom, and a pi-pi interaction by the benzofurazan structure (2,1,3-benzoxadiazole) of NBD-amino acid. Furthermore CSP 1 was able to separate esters, amides and alpha-methyl amino acids derivatized with NBD-F.     

New concept of positive photosensitive polyimide: Reaction development patterning (RDP)

A soluble multiblock copolyimide without specific functional groups such as OH and COOH was prepared by a direct one‐pot polycondensation of two types of dianhydrides and diamines in the presence of γ‐valerolactone/pyridine catalyst using N‐methylpyrrolidone (NMP)/toluene mixture as a solvent. The polyimide film containing the photosensitive agent diazonaphthoquinone (DNQ) compound gave positive‐tone behavior by UV irradiation, followed by development in a mixture of ethanolamine/NMP/H₂O (1/1/1 by weight). The scanning electron microscopic photograph of the resultant image showed fine patterns with about 20 μm film thickness. Its pattern forming was based on the photorearrangement of diazonaphthoquinone, a process in which the ring‐opening reaction of imide units of the polyimide with the amine used as a developer and the following degradation of the polymer are induced. Such a new imaging technique combines principles of photolithography and etching of a polyimide to give, what we call, reaction development patterning in which the main chemical reactions directly related to the pattern formation occur during development. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3451–3463, 2001     

μSR Study of the Unusual Magnetic Ordering in the Frustrated Antiferromagnet Zn(Cr x Ga1−x )2O4

μSR spectra on the spin frustrating spinel antiferromagnet Zn(Cr _x Ga_1−x )₂O₄ (x=0.9,1.0) have been measured. For x=1.0 compound, both the relaxation rate and the initial asymmetry showed distinct anomalies at the Néel temperature. The magnetic susceptibility for the x=0.9 compound was known to have a faint peak at around 12 K, whose origin was not clear so far. Our μSR study revealed that this temperature is the onset temperature of development of the magnetic correlation accompanied by appreciable spin fluctuations. This revised version was published online in September 2006 with corrections to the Cover Date.     

Activation Analysis of Several Species of Marine Invertebrates as Indicators of Environmental Conditions

Marine invertebrates are well known to accumulate trace metals from seawater, plankton, sea plants, and sediments. To test the usefulness of such organisms as a bio-indicator of environmental conditions, we have determined levels of trace elements in tissue of twelve species of marine invertebrates by photon and neutron activation analysis. Relatively higher concentration of elements were observed for Ni and Sn in mid-gut gland, for Cu and Zn in oyster tissues, for Se in swimming crabs, for Cu, Fe, and Se in gills of swimming crabs. Our results indicate that mid-gut gland of ear-shell will be useful as the indicator of environmental conditions.     

Saccharide Sensing Based on Saccharide‐Induced Conformational Changes in Fluorescent Boronic Acid Polymers

Summary: A novel fluorometric saccharide detection strategy has been established by utilizing saccharide‐induced conformational changes in copolymers containing boronic acid and fluorescent units. The polymer chain changes its conformation due to an alteration of the charge state induced by binding with saccharides. The conformational changes are conveniently detected by monitoring excimer to monomer intensity ratio in the fluorescence spectra. Thus, the present strategy would be a promising way for the creation of highly selective and sensitive saccharide‐sensing systems.

Saccharide‐induced conformational change in copolymers containing boronic acid units.