Transport of monosaccharides through a liquid membrane mediated by lipophilic alkaline earth metal complexes

Lipophilic alkaline earth metal complexes, prepared from the corresponding metal hydroxides and phosphoric acid diesters, are quite effective for the transport of some monosaccharides, especially ribose, across a chloroform liquid membrane under neutral conditions.     

Luminescence study of the optically active uranyl crystals: NaUO2(CH3COO)3

Luminescence spectra of NaUO₂(CH₃COO)₃ single crystals at 4.2 K have been investigated by means of site selective excitation technique, circularly polarized luminescence and time-resolved luminescence spectroscopy. It has been found that the splittings in the pure electronic and their vibronic transition lines are ascribed to the transitions from two different emitting sites.     

Partial state feedback control of chaotic neural network and its application

The chaos control in the chaotic neural network is studied using the partial state feedback with a control signal from a few control neurons. The controlled CNN converges to one of the stored patterns with a period which depends on the initial conditions, i.e., the set of control neurons and other control parameters. We show that the controlled CNN can distinguish between two initial patterns even if they have a small difference. This implies that such a controlled CNN can be feasibly applied to information processing such as pattern recognition.     

On surfaces whose twistor lifts are harmonic sections

We study surfaces whose twistor lifts are harmonic sections, and characterize these surfaces in terms of their second fundamental forms. As a corollary, under certain assumptions for the curvature tensor, we prove that the twistor lift is a harmonic section if and only if the mean curvature vector field is a holomorphic section of the normal bundle. For surfaces in four-dimensional Euclidean space, a lower bound for the vertical energy of the twistor lifts is given. Moreover, under a certain assumption involving the mean curvature vector field, we characterize a surface in four-dimensional Euclidean space in such a way that the twistor lift is a harmonic section, and its vertical energy density is constant.     

A Dixmier-Schaefer-Zhang theorem for operator algebras

Schaefer and Zhang have recently obtained an analogue, for sequentially order continuous functionals on , of a much earlier theorem of Dixmier. In this note it is shown that the Schaefer-Zhang Theorem has a natural generalisation to non-commutative -algebras. These results are obtained as consequences of our main theorem which is concerned with affine functions on compact convex sets.

     

Synthesis of new [8Fe-7S] clusters: a topological link between the core structures of P-cluster, FeMo-co, and FeFe-co of nitrogenases

A coordinatively unsaturated dinuclear iron(II) complex of bulky thiolates, [(TipS)Fe(micro-SDmp)]2 (1; Tip = 2,4,6-(i)Pr(3)C(6)H(2), Dmp = 2,6-(mesityl)(2)C(6)H(3)), was synthesized from stepwise reactions of Fe{N(SiMe(3))2}2 with 1 equiv of HSDmp and then with 1 equiv of HSTip. Complex 1 was found to react with elemental sulfur (S8) in toluene to generate a new class of [8Fe-7S] cluster, [(DmpS)Fe(4)S(3)]2(micro-SDmp)2(micro-STip)(micro(6)-S) (2). The cluster 2 was also produced from one-pot reactions of Fe{N(SiMe(3))2}2 + HSDmp + HSTip + S8 (8:6:10:7/8) and Fe3{N(SiMe(3))2}2(micro-STip)4 + HSDmp + S8 (8/3:16/3:7/8), where another [8Fe-7S] cluster, [(TipS)Fe(4)S(3)]2(micro-SDmp)2{micro-N(SiMe(3))2}(micro(6)-S) (3), was also found as a minor byproduct. In either of the clusters, two Fe(4)S(3) incomplete cubane units are connected by three anionic ligands, namely three thiolate S atoms for 2 or two thiolate S atoms and one amide N atom for 3, and one hexa-coordinate S atom resides at the center of the [8Fe-7S] core. They have a common Fe(II)(5)Fe(III)3 oxidation states, and an S = 1/2 ground spin state was indicated by rhombic EPR signals at 10 K with g = 2.19, 2.07, and 1.96 for 2 and g = 2.13, 2.06, and 1.93 for 3. The structural relevance of clusters 2 and 3 to P-cluster, FeMo-co, and FeFe-co of nitrogenases is discussed.     

Miscibility of nifedipine and hydrophilic polymers as measured by (1)H-NMR spin-lattice relaxation

The miscibility of a drug with excipients in solid dispersions is considered to be one of the most important factors for preparation of stable amorphous solid dispersions. The purpose of the present study was to elucidate the feasibility of (1)H-NMR spin-lattice relaxation measurements to assess the miscibility of a drug with excipients. Solid dispersions of nifedipine with the hydrophilic polymers poly(vinylpyrrolidone) (PVP), hydroxypropylmethylcellulose (HPMC) and alpha,beta-poly(N-5-hydroxypentyl)-L-aspartamide (PHPA) with various weight ratios were prepared by spray drying, and the spin-lattice relaxation decay of the solid dispersions in a laboratory frame (T(1) decay) and in a rotating frame (T(1rho) decay) were measured. T(1rho) decay of nifedipine-PVP solid dispersions (3 : 7, 5 : 5 and 7 : 3) was describable with a mono-exponential equation, whereas T(1rho) decay of nifedipine-PHPA solid dispersions (3 : 7, 4 : 6 and 5 : 5) was describable with a bi-exponential equation. Because a mono-exponential T(1rho) decay indicates that the domain sizes of nifedipine and polymer in solid dispersion are less than several nm, it is speculated that nifedipine is miscible with PVP but not miscible with PHPA. All the nifedipine-PVP solid dispersions studied showed a single glass transition temperature (T(g)), whereas two glass transitions were observed for the nifedipine-PHPA solid dispersion (3 : 7), thus supporting the above speculation. For nifedipine-HPMC solid dispersions (3 : 7 and 5 : 5), the miscibility of nifedipine and HPMC could not be determined by DSC measurements due to the lack of obviously evident T(g). In contrast, (1)H-NMR spin-lattice relaxation measurements showed that nifedipine and HPMC are miscible, since T(1rho) decay of the solid dispersions (3 : 7, 5 : 5 and 7 : 3) was describable with a mono-exponential equation. These results indicate that (1)H-NMR spin-lattice relaxation measurements are useful for assessing the miscibility of a drug and an excipient in solid dispersions.     

Nuclear protein profiling of Jurkat cells during heat stress-induced apoptosis by 2-DE and MS/MS

Heat stress causes severe constraints on numerous physiological functions of cells, such as the repression of splicing of mRNA precursors. In this study, we performed proteomic profiling of a nuclear fraction of Jurkat cells during heat stress using 2-DE and LC-MS/MS. We found 10 protein spots whose expression had changed after heat stress at 43 degrees C for 30 min. Seven of those protein spots, periodic tryptophan protein 1 homolog (PWP1), importin beta-1 subunit, sumoylated protein, splicing factor 3a subunit 3 (SF3a3), TAR DNA-binding protein 43, U2 small nuclear ribonucleoprotein auxiliary factor 35 kDa subunit (U2AF35) and small ubiquitin-related modifier-1 (SUMO-1) were downregulated, while three other protein spots, Protein SET, 40S ribosomal protein SA and 60S acidic ribosomal protein P0 were upregulated by the heat stress. We focused on the downregulation of two splicing factors, which might participate in the repression of pre-mRNA processing by heat stress, leading to cell apoptosis.     

Effect of wood properties on within-tree variation in ultrasonic wave velocity in softwood

The radial variations in the velocity of longitudinal waves propagating through Japanese cedar and Japanese cypress were experimentally investigated. In addition, the tracheid length (TL), microfibril angle (MFA), air-dried density (AD), and moisture content (MC) were measured in order to determine the effect of wood properties on velocity variations within the wood trunk. For both species, the longitudinal wave velocities measured in the longitudinal direction (V_L) exhibited minimum values near the pith. For Japanese cedar, V_L increased from 3600 m/s toward the bark and soon attained a constant value (=4500 m/s). On the other hand, for Japanese cypress, V_L kept increasing from 4000 m/s near the pith to 4800 m/s at the bark. These radial variations in V_L coincided with those in the tracheid length. V_L exhibited strong correlations with TL and MFA with a significant level of (p < 0.01). These findings suggest that the TL and MFA greatly affect the radial variation in the ultrasonic wave velocity in softwood.