Magnetic Alignment in Solid State and Temperature Hysteresis in Aqueous Tetrahydrofuran Solution for Tetrathiafulvaleno[18]annulenes

Tris(tetrathiafulvaleno)dodecadehydro[18]annulene‐hexaesters have a multi‐functionality that is very sensitive to small differences in the ester side‐chain. Self‐aggregation of the [18]annulenes in amphiphilic media such as THF–H₂O (v/v, 1:1) either produce a fibrous structure or result in temperature hysteresis of the color and ¹H NMR signals. This temperature hysteresis in solution is due to both strong self‐aggregation behavior and unique cluster formation in a binary solution of THF and water.     

Formation mechanism and luminescence appearance of Mn-doped zinc silicate particles synthesized in supercritical water

Luminescence appearance of Mn-doped zinc silicate (Zn₂SiO₄:Mn²⁺, ZSM) formed in supercritical water at 400 °C and 29 MPa at reaction times from 1 to 4320 min was studied in the relation to its phase formation mechanism. Appearance of luminescent ZSM from green emission by α-ZSM and yellow emission by β-ZSM occurred over the same time period during the onset of phase formation at a reaction time of 2 min. Luminescence appeared at a much lower temperature and at shorter reaction times than the conventional solid-state reaction. Needle-like-shaped α-ZSM was the most stable particle shape and phase in the supercritical water reaction environment and particles formed via two routes: a homogenous nucleation route and a heterogenous route that involves solid-state diffusion and recrystallization.     

An accurate quantitative analysis of polymorphic content by chemometric X-ray powder diffraction.

Data from X-ray powder diffraction (XRD) were subjected to a partial least-squares regression analysis (PLS) to build a calibration model for predicting the polymorphic content of carbamazepine (CBZ). The effectiveness of the PLS method in the construction of calibration models was analyzed by a scientific approach based on a regulation vector. CBZ forms I and III were characterized by differential scanning calorimetry (DSC) and XRD. Powder mixtures of forms I and III at various ratios (0-100% w/w; form III) were subjected to XRD. Five diffraction peaks were used for the peak-area method to compare with PLS. The results obtained by PLS had a better predictive accuracy compared to those of the peak-area method. The XRD-PLS method was established as a non-destructive, non-contact way to avoid the particle orientation effect based on statistical theory.     

Certain CR submanifolds of maximal CR dimension of complex space forms

We study m-dimensional real submanifolds with (m−1)-dimensional maximal holomorphic tangent subspace in complex space forms. On such a manifold there exists an almost contact structure which is naturally induced from the ambient space and in this paper we study the anti-commutative condition of the almost contact structure and the second fundamental form of these submanifolds and we characterize certain model spaces in complex space forms.     

Spectral Representation and the Averaging Problem in Cosmology1

We investigate the averaging problem in cosmology as the problem of introducing a distance between spaces. We first introduce the spectral distance, which is a measure of closeness between spaces defined in terms of the spectra of the Laplacian. Then we define S _N, a space of all spaces equipped with the spectral distance. We argue that S _N can be regarded as a metric space and that it also possesses other desirable properties. These facts make S _N a fundamental arena for spacetime physics. Then, we apply the spectral framework to the averaging problem: We describe the model-fitting procedure in terms of the spectral representation, and also discuss how to analyze the dynamical aspects of the averaging procedure with this scheme. In these analyses, we are naturally led to the concept of the apparatus-dependent and the scale-dependent effective evolution of the universe. These observations suggest that the spectral scheme seems to be suitable for the quantitative analysis of the averaging problem in cosmology.     

Constituents of holothuroidea, 14. Isolation and structure of new glucocerebroside molecular species from the sea cucumber Stichopus japonicus

Five glucocerebroside molecular species, SJC-1-SJC-5, have been isolated from the less polar lipid fraction of a chloroform/methanol extract of the sea cucumber Stichopus japonicus. The structures of these glucocerebroside molecular species were determined on the basis of chemical and spectroscopic evidence. SJC-1, SJC-2, and SJC-3 are typical sphingosine- and phytosphingosine-type glucocerebroside molecular species with nonhydroxylated and hydroxylated fatty acyl moieties. SJC-4 and SJC-5 are also sphingosine-type glucocerebroside molecular species with hydroxylated fatty acyl moieties, although they are new glucocerebroside molecular species with unique sphingosine bases.     

Antioxidant ortho-benzoyloxyphenyl acetic acid ester,vaccihein A,from the fruit of rabbiteye blueberry (Vaccinium ashei)

A new ortho-benzoyloxyphenyl acetic acid ester, called vaccihein A (1), was isolated from the fruit of rabbiteye blueberry (Vaccinium ashei). The chemical structure was determined on the basis of spectroscopic data. Compound 1 had antioxidative activity using the ferric thiocyanate method. In addition, 1 showed a scavenging effect on the stable free radical 1,1-diphenyl-2-picrylhydrazyl.     

Screening and diagnosis of beta-ureidopropionase deficiency by gas chromatographic/mass spectrometric analysis of urine

Dihydropyrimidine dehydrogenase (DHPDase), dihydropyrimidinase (DHPase) and beta-ureidopropionase (betaUPase) are the enzymes that catalyze the first, second, and third steps of the degradation of pyrimidines, respectively. beta-Ureidopropionate (betaUP) and beta-ureidoisobutyrate (betaUIB) are increased in the urine of patients with betaUPase deficiency. The original case in which betaUPase deficiency was discovered by NMR spectroscopy was an 11-month-old patient who presented with hypotonia and dystonic movement. We detected a second but asymptomatic case during a pilot study of neonatal screening with filter-paper urine, urease pretreatment and gas chromatography/mass spectrometry (GC/MS). The urease pretreatment of urine without fractionation resulted in a high recovery of these polar ureide compounds and allowed the highly sensitive GC/MS detection and diagnosis of betaUPase deficiency. betaUP and betaUIB were identified using GC/MS techniques. In the urine of the neonate with betaUPase deficiency, betaUP and betaUIB were persistently increased. Thymine, 5,6-dihydrothymine and 5,6-dihydrouracil were increased only moderately but significantly. It is known that thymine and uracil increase markedly in DHPDase deficiency, and 5,6-dihydrothymine and 5,6-dihydrouracil increase in DHPase deficiency. Therefore, betaUPase deficiency can be differentially diagnosed from the first and second enzyme deficiencies. Application of this specific and sensitive diagnostic procedure will lead to an understanding of the clinical heterogeneity of betaUPase deficiency. Furthermore, the identification of patients with defects in pyrimidine metabolism will enable doctors to avoid cancer chemotherapy with pyrimidine analogues such as 5-fluorouracil, which could be dangerous for these patients.     

Photo-initiated bromination of octakis(1,1,2-trimethylpropyl)octasila- cubane with tetrabromomethane

Bromination reactions of octasilacubane via radical intermediates are demonstrated. In the absence of oxygen, UV-light irradiation of octakis(1,1,2-trimethylpropyl)octasilacubane (1) with tetrabromomethane in benzene resulted in the formation of only exo,exo-4,8-dibromoctakis(1,1,2-trimethylpropyl)tetracyclo[3.3.0.0^2,7.0^3,6]octasilane(2). However, in the presence of oxygen, the reaction of 1 with tetrabromomethane took place without irradiation, producing 2 and a novel type of the monooxidation product, dibromooxahomosecocubane (3). For the formation of these products, an electron-transfer mechanism involving successive cleavage of the Si–Si bonds, followed by skeletal rearrangement is proposed.