Structural Changes and Phase Transitions in Whitlockite-Like Phosphates

New compounds with a g -Ca 3 (PO 4 ) 2 structure type were found in three systems: Sr 9+ x M 1.5 m x (PO 4 ) 7 ( M = Mn, Fe, Co, Ni, Cu, and Cd; space group R 3 m ; Z = 3), Sr 9 R (PO 4 ) 7 ( R = Al, Sc, Cr, Fe, Ga, In, and Gd-Lu; space group P 2/ c , Z = 4), and Sr 9+2 x M 1+ x A 1 m 6 x (PO 4 ) 7 ( M = Mn, Ni, Cd; space group R 3 c and Z = 6 for A = Na, K; space group P 2/ m and Z = 4 for A = Li). Crystal structures of these compounds were determined by time-of-flight neutron, synchrotron X-ray, and laboratory X-ray powder diffraction. Reversible polar-to-centrosymmetric phase transitions ( R 3 c {\begin{array}{c}\\[-14pt]\hspace*{.5pt}\to\\[-7pt]\hspace*{-.5pt}\gets \end{array}} R 3 m ) were observed at high temperatures in Ca 3 m x Sr x (PO 4 ) 2 (0 h x h 12/7), Ca 10.5 m 1.5 x Fe x (PO 4 ) 7 (0 h x h 1), and Ca 9 R (PO 4 ) 7 . Solid solutions Ca 3 m x Sr x (PO 4 ) 2 (13/7 h x h 16/7) are centosymmetric with space group R 3 m at room temperature. These phase transitions were studied by high-temperature X-ray diffraction, second-harmonic generation, DSC, electric-conductivity and dielectric measurements.     

Evolution of solid phase homochirality for a proteinogenic amino acid

The inexorable evolution of solid-phase single chirality is demonstrated for the first time for a proteinogenic amino acid. Enantioenrichment is observed both under attrition-enhanced conditions and without the aid of particle grinding. Differences in the form of the conversion profiles for the process under the two sets of conditions provide suggestions concerning the mechanism of the transformation.     

Extraction of amphetamines and methylenedioxyamphetamines from urine using a monolithic silica disk-packed spin column and high-performance liquid chromatography-diode array detection

To overcome the limitations of solid-phase extraction, we developed a device comprising a spin column packed with octadecyl silane-bonded monolithic silica for extracting amphetamines and methylenedioxyamphetamines from urine. Urine (0.5mL), buffer (0.4mL), and methoxyphenamine (internal standard) were directly put into the preactivated column. The column was centrifuged (3000rpm, 5min) for sample loading and washed. The adsorbed analytes were eluted and analyzed by high-performance liquid chromatography, without evaporation. The results were as follows: linear curves (drug concentrations of 0.2-20microg/mL); correlation coefficients >0.99; detection limit, 0.1microg/mL. The proposed method is not only useful for drugs from biological materials but also highly reproducible for the analysis of these drugs in urine.     

Time-dependent growth of zinc hydroxide nanostrands and their crystal structure

Positively-charged crystalline zinc hydroxide nanostrands with a diameter of 2 nm and a length of a few micrometres rapidly grew in dilute aqueous solution of zinc nitrate and aminoethanol. The nanostrands were composed of hexagonal clusters of [Zn(61)(OH)(116)(H(2)O)(n)](6+).     

Design of biomolecular interface for detecting carbohydrate and lectin weak interactions

A hybrid functional biomolecular interface designed at a molecular size level is very effective at capturing an analyte with high sensitivity even if the interaction is very weak, as when detecting proteins with carbohydrate. We designed and processed a protein (lectin) recognition molecular interface taking the following points into consideration: (1) the height (molecular length) difference between the capturing and spacer molecules; (2) the ratio of capturing molecules in the recognition interface. When the height difference between the maltoside part (Concanavalin A (Con A) recognition group) and the OH group terminated spacer molecules exceeded (>(CH(2))(6)), the association rate constant (k(a)) became larger (k(a)(1/Ms): ～2.6 times) and the dissociation constant (K(D)) became much smaller (K(D)(M): 1.0 × 10(-6): ～0.17 times) compared with the similar heights (lengths) of both molecular interfaces. With regard to maltoside density, a 100% maltoside monolayer was unsuitable for detecting Con A. We constructed a nanostructured recognition site with a maltoside part of 10%, which was the most suitable ratio for Con A detection. The binding interaction between Con A and the maltoside group was changed from monovalent binding to bivalent binding when the maltoside part was diluted in the recognition interface. From electrochemical measurements, even though there was a small amount of maltoside component on the suitable recognition monolayer, quality similar to that of 100% maltoside was observed.     

Structure-odor relationships of α-santalol derivatives with modified side chains

(Z)-α-Santalol, which has a unique woody odor, is a main constituent of sandalwood essential oil. We investigated the structure-odor relationship of (Z)-α-santalol and its derivatives, focusing on the relationship between the structure of the side chain and the odor of the compounds. Various α-santalol derivatives (aldehydes, formates, and acetates) were synthesized from (Z)- and (E)-α-santalol, which were prepared from (+)-3-bromocamphor through modifications of a reported synthetic route. The Z- and E-isomers of α-santalols have different double-bond configurations in the side chain. Analogues with saturated side chains were also prepared from the corresponding α-santalols, and the odors of the all the prepared compounds were evaluated. We found that the odors of the Z-isomers (woody) were similar to those of the corresponding saturated compounds, but clearly different from the odors of the corresponding E-isomers (odorless, fresh, or fatty). These results indicate that the relative configuration of the side chain with respect to the santalane frame plays an important role in the odor of α-santalol. E-configuration in the side chain eliminates the woody odor character of α-santalol and its examined derivatives, whereas the Z-configuration or saturation of the carbon side chain does not.     

Twisted flavors and tribimaximal neutrino mixing

A new framework for handling flavor symmetry breaking in the neutrino sector is discussed where the source of symmetry breaking is traced to the global property of right-handed neutrinos in extra-dimensional space. Light neutrino phenomenology has rich and robust predictions such as the tribimaximal form of generation mixing, controlled mass spectrum, and no need of flavor mixing couplings in the theory.     

Analysis of protein-protein interactions with a multi-capillary electrophoresis instrument

Protein-protein interactions were analyzed by zone electrophoresis of premixed equilibrium mixtures of a fluorescence-labeled protein at a constant concentration and unlabeled protein at a variety of concentrations using a 96-CE instrument equipped with a LIF detector. The interactions between labeled-con A versus succinylated ovalbumin, labeled-trypsin versus four proteinaceous trypsin inhibitors and labeled-insulin versus seven anti-insulin monoclonal antibodies were analyzed using a dual buffer system, in which a 60 mM borate-Na buffer (pH 9.35) was used as electrophoresis buffer and 60 mM MOPS-Na (pH 7.35) containing 0.1% Tween 20 was used as a sample buffer. The dual buffer system allowed fast and reproducible analyses of interactions at a physiological pH using uncoated fused-silica capillaries. The change in the mobility moment, the first statistical moment of an electropherogram on the mobility axis (Shimura, K., Uchiyama, N., Enomoto, M., Matsumoto, H., Kasai, K., Anal. Chem. 2005, 77, 564-572), of the labeled proteins were analyzed as a function of the concentration of unlabeled proteins. The dissociation constants for seven antibodies ranging from sub nanomolar to micromolar was determined based on the results of one cycle of parallel electrophoresis runs, which completed in 30 min using 20 pmol (120 ng) of labeled insulin and 5 pmol (750 ng) each of the mAb.     

Duty cycle enhancement of an orthogonal acceleration TOF mass spectrometer using an axially-resonant excitation linear ion trap

We report a new technique to enhance detection duty cycle of an orthogonal-acceleration time-of-flight mass spectrometer (oaTOF) over a broad mass range. To this end, we used an axially-resonant-excitation linear ion trap, which ejects ions axially and mass selectively into a non-mass-selective linear ion trap in front of the TOF pusher. A delay between the ejection timing of the non-mass-selective LIT and the push timing of the oaTOF was swept mass-synchronously with the axially-resonant-excitation linear ion trap, so that ions are detected with duty cycle larger than 60% over a wide mass range from m/z 174.1 to 1922.0, which is 3 to 10 times better than conventional oaTOF.     

First highly stereoselective synthesis of anti-alpha-trifluoromethyl-beta-amino acid derivatives

The Reformatsky-type reaction of 2-bromo-3,3,3-trifluoropropanoic imide with various types of imines, in the presence of ZnBr2 as a Lewis acid in THF at 0 degrees C for 3 h, gave the corresponding alpha-trifluoromethyl-beta-amino acid derivatives in a highly anti-selective manner.