Molecular-shape selectivity by molecular gel-forming compounds: bioactive and shape-constrained isomers through the integration and orientation of weak interaction sites

A molecular gel system was assembled on carrier particles and the integrated effect of weak interaction sites enabled highly efficient separation of the bioactive and shape-constrained isomers of tocopherols, β-carotene, and polycyclic aromatic hydrocarbons (PAHs) by multiple interaction mechanisms.     

On Symmetric Stable-Type Processes with Degenerate/Singular Lévy Densities

Journal of Theoretical Probability - We consider symmetric stable-type processes with degenerate/singular Lévy densities via Dirichlet form theory. We give conditions of some global path...     

Changes in Hip and Knee Muscle Strength in Patients Following Total Hip Arthroplasty

Objective: To investigate changes in hip and knee muscle strength in patients before and after total hip arthroplasty (THA) in comparison with that in healthy adults. Methods: The study included 21 women who underwent unilateral THA (THA group) and 21 age-matched healthy women (healthy group). Maximal isometric strengths of hip flexors, extensors, and abductors, and knee extensors and flexors were measured before surgery and at 4 weeks and 6 months after surgery. Results: Before surgery, muscle strength on both sides, except for hip flexors on the uninvolved side, was significantly lower in the THA group than the corresponding muscle strength in the healthy group. Up to 6 months after THA, strength of all muscle groups on both sides was significantly improved compared with their preoperative status, although the knee extensor strength on the involved side temporarily worsened at 4 weeks. However, the strength of hip extensors and knee extensors on the involved side, and hip abductors on both sides in the THA group remained below that in the healthy group. Conclusions: Our results suggest that rehabilitation specialists should consider increasing the focus on the uninvolved side and encourage patients to continue strength training beyond 6 months after surgery.     

Magnesium K‐edge XANES spectroscopy of geological standards

Magnesium K‐edge X‐ray absorption near‐edge structure (XANES) spectra have been investigated to develop a systematic understanding of a suite of Mg‐bearing geological materials such as silicate and carbonate minerals, sediments, rocks and chemical reagents. For the model compounds the Mg XANES was found to vary widely between compounds and to provide a fingerprint for the form of Mg involved in geologic materials. The energy positions and resonance features obtained from these spectra can be used to specify the dominant molecular host site of Mg, thus shedding light on Mg partitioning and isotope fractionation in geologic materials and providing a valuable complement to existing knowledge of Mg geochemistry.     

Assembled structures of nanocrystals in polymer/calcium carbonate thin-film composites formed by the cooperation of chitosan and poly(aspartate)

Assembled structures of calcium carbonate (CaCO₃) nanocrystals have been examined for polymer/CaCO₃ thin-film composites synthesized through a self-organization process inspired by biomineralization. For the crystallization of CaCO₃, a thin-film matrix of chitosan has been used as a polymeric substrate. When the matrix is immersed into a supersaturated aqueous solution of CaCO₃ containing 1.4 × 10⁻³ wt % poly(aspartate) (PAsp), thin-film crystals of CaCO₃ are formed spontaneously. Three kinds of disklike films have been observed under a polarizing optical microscope. Electron diffraction analyses of each film have revealed that one is aragonite, displaying radial orientation of the c axes, and the others are vaterite, exhibiting different orientations. Detailed observation by scanning electron microscopy has clarified that these films are assemblies of crystalline particles 10–20 nm in size. The thin-film composites have been obtained over a PAsp concentration range of 4.4 × 10⁻⁴ to 1.0 × 10⁻² wt %. Vaterite formation becomes dominant when the concentration of PAsp is increased. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 5153–5160, 2006     

Thermoanalytical characterization of carbon/carbon hybrid material, Apple Woodceramics

Woodceramics, a carbon/carbon composite of plant-originated carbon reinforced by glassy carbon from phenolic resin, was prepared from apple pomace at carbonizing temperatures of 1073 K (AWC800) and 1473 K (AWC1200), and characterized by thermoanalytical methods and X-ray diffraction (XRD). Simultaneous differential scanning calorimetry (DSC) and thermogravimetric (TG) showed complicated overlapping reactions similar to those of coal. The initial temperature of pyrolysis was obtained by fitting logistic functions to observed TG data. The results suggested that AWC1200 contained more volatile matter than AWC800. In an inert atmosphere, complicated devolatilization takes place. In an oxidizing atmosphere, thermal change occurs roughly in four steps: desorption of physically adsorbed matter; pyrolysis into aliphatic and aromatic fragments; ignition; combustion of char. The oxidation resistance of AWC1200 was superior to AWC800.     

New Plasmon Waveguides Composed of Twin Metal Wedges with a Nano Gap

We have numerically shown the existence of coupled wedge plasmons (CWPs) which propagates along a nano gap of a twin metal wedge. The CWPs are formed by wedge plasmons which can interact with each other. The dispersion relations of the wavenumber, propagation distance, and beam area of CWPs, are described and show that the characteristics of CWPs are similar to those of wedge plasmons and of gap plasmons. We also propose a new plasmon waveguide composed of twin metal wedges with a nano gap.     

Practical synthesis of a neuropeptide Y antagonist via stereoselective addition to a ketene

[Reaction: see text]. The synthesis of neuropeptide Y antagonist 1, currently under clinical investigation for the treatment of obesity, is described. The convergent synthesis from trans-spirolactone carboxylic acid intermediate 2a and aminopyrazole 3 is predicated on a stereoselective route to the former. The coupling reaction of ethyl 4-oxocyclohexanecarboxylate (10a) with lithiated isonicotinamide 11 was investigated in detail, but even optimized conditions only provided a 45:55 ratio of trans:cis isomers (12a:12b). While selective crystallization schemes were developed to isolate the thermodynamically less stable trans isomer 2a, improved stereocontrol was subsequentially achieved by the application of ketene chemistry. The ketene formation and quench was investigated under a variety of conditions aimed at maximizing the trans:cis ratio. Reacting a mixture of carboxylic acids 2a and 2b with POCl3 in THF, followed by concomitant addition of tert-butyl alcohol in the presence of TMEDA at 35 degrees C provided a 4:1 ratio of trans:cis tert-butyl esters (18a:18b) via in situ ketene formation. Ester hydrolysis, followed by selective crystallization of undesired 2b as the HCl salt, led to isolation of 2a in 47% overall yield. Aminopyrazole intermediate 3 was synthesized via the condensation reaction of 2-fluorophenylhydrazine hydrochloride (4a) with acrylonitrile derivative 5 in 65-70% yield. Coupling of advanced intermediates 2a and 3b via activation with thionyl chloride gave a 92% yield of 1.     

Determination of bithionol, bromophen, nitroxynil, oxyclozanide, and tribromsalan in milk with liquid chromatography coupled with tandem mass spectrometry

LC/MS/MS was developed to determine the residues of bithionol (BTN), bromofen (BMF), nitroxynil (NTX), oxyclozanide (OCZ), and tribromsalan (TBS) in milk. Samples were extracted with ethyl acetate and cleaned up by liquid-liquid separation with acetonitrile and n-hexane. The compounds were determined by RP-LC using a C18 column with 0.1% formic acid-methanol. Mass spectral acquisition was performed in the negative mode by applying selected-reaction monitoring. The method was validated in milk spiked with these compounds at 5-600 microg/kg; average recoveries were in the range 83.8-97.1%, with RSD values of 1.4-8.0%. The interassay RSDs were less than 11%. The LODs of these compounds in milk were 0.1 microg/kg. The method was applied to 24 raw milk samples. The concentration of these compounds in all samples was lower than the Japanese maximum residue limits. The method is rapid, sensitive, and specific for monitoring residues of BTN, BMF, NTX, OCZ, and TBS in milk.     

Cohaerins C-F, four azaphilones from the xylariaceous fungus Annulohypoxylon cohaerens

Four azaphilones named cohaerins C-F, along with 4,5,4′,5′-tetrahydroxy-1,1′-binaphthyl were isolated from the methanolic extract of the stromata of Annulohypoxylon cohaerens (Ascomycetes, Xylariaceae). Cohaerins C-E constitute typical azaphilones, bearing a γ-lactone ring, while cohaerin F has an unprecedented carbon skeleton, lacking the lactone ring of the azaphilones and with an aliphatic side chain being attached directly to the azaphilone backbone by a C-C bond. Their structures were determined by 2D NMR, IR, UV, and CD spectroscopy. They showed moderate inhibitory activity of nitric oxide production in RAW cells, and strong and nonselective antimicrobial effects.