Determination of testosterone propionate in human plasma by gas chromatography-mass spectrometry

A specific, sensitive and accurate quantitative analysis of testosterone propionate in human plasma was developed using gas chromatography-mass spectrometry-selected-ion monitoring. For the calculation of testosterone propionate in plasma, peak height ratios were measured by selected-ion monitoring performed on the molecular ions of the trifluoroacetyl derivative of testosterone propionate (m/z 440) and testosterone propionate-19,19,19-d3 (m/z 443). The sensitivity of the method was judged from the lower limit of the detection of the mass spectrometer which was at 20 pg. The inter-assay coefficients of variation and relative error at a concentration of 1.31 ng/ml of plasma were 5.47% and -2.3%, respectively. The method described was applied to the determination of plasma concentrations of testosterone propionate-19,19,19-d3 following an intramuscular dose of testosterone propionate-19,19,19-d3 in a healthy male volunteer.     

Transformation of ionic liquid into carbon nanotubes in confined nanospace

We have developed a two-step filling process for the nano-reaction of ionic liquid in a tip-closed SWNT, where fullerenes are inserted at the end of the host SWNT as a plug to prevent the leakage of the confined ionic liquid during heat treatment.     

Development of non-destructive isotopic analysis methods using muon beams and their application to the analysis of lead

Journal of Radioanalytical and Nuclear Chemistry - Elemental isotopic ratios are measured in various research fields and provide useful information regarding age, origin, geological and biological...     

Liquid phase formation of alkyl- and perfluoro-phosphonic acid derived monolayers on magnesium alloy AZ31 and their chemical properties

Alkyl- and perfluoro-phosphonic acid derived SAMs were successfully formed on Mg alloy by liquid phase method for the first time. The chemical and anticorrosive properties of the prepared SAMs on magnesium alloys were characterized using contact angle measurements, X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and electrochemical measurements. Water contact angle measurements revealed that the maximum advancing/receding water contact angles of n-octyl (OP: CH(3)(CH(2))(7)PO(OH)(2)), n-dodecyl (DP: CH(3)(CH(2))(11)PO(OH)(2)), n-octadecyl (ODP: CH(3)(CH(2))(17)PO(OH)(2)) phosphonic acid, and 2-(perfluorohexyl)ethyl (PFEP: CF(3)(CF(2))(5)CH(2)CH(2)PO(OH)(2)) phosphonic acid were 105.1/64.7°, 108.3/69.6°, 111.9/75.2°, and 115.2/67.4° respectively. In the case of alkylphosphonic acid SAMs (OP, DP, and ODP), the advancing and receding water contact angles increased with an increase in the preparation time. The angle-resolved XPS (AR-XPS) data revealed that the film thicknesses of the OP, DP, ODP, PFEP on Mg alloy were estimated to be 0.8, 1.2, 1.7, and 1.1 nm, respectively. The XPS O 1s data support that the phosphonic acid derived SAM is covalently bound to the oxide or hydroxide surface of the Mg alloy in a monodenate or bidenate manner. Chemical stability of the alkyl- and perfluoro-phosphonic acid modified Mg alloy surfaces was investigated using aqueous solutions at pH=4.0, 7.0, and 10.0. The contact angles of OP, DP, and PFEP modified Mg surface decreased rapidly within the first 5 min after immersion in all the aqueous solutions and were less than 20°. On the other hand, the contact angles of the ODP modified Mg alloy after immersion in aqueous solutions at pH 4, 7 and 10 for 5 min were 45.1°, 89.3,° and 85.5°, respectively. The ODP modified Mg alloy had highest chemical stability in four types of the phosphonic acid derived SAMs used in this study, indicating that the molecular density of ODP on Mg alloy would be higher than those of OP, DP, PFEP on Mg alloy. The corrosion resistance of ODP modified Mg alloy was investigated by potentiodynamic polarization curve measurements. The ODP modified Mg alloy exhibits protective properties in a solution containing Cl(-) ions compared to unmodified Mg alloy.     

Synthesis of 3′-allylindoline spirobenzopyrans derived from 3-allyl-3H-indoles

In this study, 8 new spirobenzopyrans were synthesized. A novel, three-step, facile route for the synthesis of 3′-allylindoline spirobenzopyrans via 3-allyl-3H-indoles was developed. The newly synthesized spirobenzopyrans were evaluated for their photochromic properties. The presence of an allyl moiety at the 3′ position did not disturb the photochromic response. The steric effects of the diallyl groups at the 3′ position affected the interconversion between colored and colorless forms. Therefore, the allyl chain in 3′-allylindoline spirobenzopyrans can be utilized to attach these compounds to a molecular matrix. Consequently, this synthetic methodology could be readily applied to the creation of new photo-switchable materials.     

Giant motion of La atom inside C82 cage

An anomalous charge density distribution of La atom encapsulated in a C₈₂ cage has been revealed for La@C₈₂ by the maximum entropy method (MEM)/Rietveld analysis using synchrotron powder diffraction data. The obtained La atom charge density shows a feature almost like a bowl or a hemisphere, suggesting that the La atom has a giant motion (large amplitude motion) inside the C₈₂ cage at room temperature. From the obtained MEM charge density, the main results are (1) the cage structure of La@C₈₂ (I) has C_2V symmetry; (2) La atom locates at an off-centered position adjacent to a six-membered ring of the carbon cage; (3) the nearest La–C distance is 2.55(8) and (4) the amount of charge transfer from the La atom to the carbon cage is about 3.2 e, which corresponds to the nominal electronic structure, La³⁺@C₈₂³⁻.     

Isolation of mitogenic substance from sclerotia of Sclerotinia sclerotiorum IFO 9395 extracted with phosphate buffer.

The buffer extracts (3S) of sclerotia of Sclerotinia sclerotiorum IFO 9395 contained mitogenic substance(s) to murine splenocytes (Shinohara et al. Chem. Pharm. Bull., 38, 2219 (1990)). Although the native 3S was slightly mitogenic, heating of 3S induced significant mitogenic activity. To isolate the mitogen, we separated 3S by ion-exchange and gel filtration chromatographies. The isolated mitogen, named sclerogen, has a molecular mass of 32 kilodaltons (kDa) on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and the isoelectric point (pI) of 5.9 by chromatofocusing. Sclerogen was significantly mitogenic in vitro against murine splenocytes after heat denaturation, and also showed the augmentation of the primary mixed lymphocyte reaction (MLR) in vitro. However, sclerogen did not show the activation of an alternative pathway of complement and hemagglutination activity. These results suggest that sclerogen is a unique mitogen which differs from lectins and shows mitogenicity after heat denaturation.     

Preparation and characterization of macroporous polystyrene resins containing ethynyl groups and transition metal acetylide complexes

Ethynylated polystyrene resins were prepared as functionalized polymer supports by the iodination reaction of macroporous polystyrene resins and reacted with transition metal diethynyl complex (Mt = Ni) and metal halides (Mt = Rh, Pd, and Pt) in a basic solvent using cuprous iodide as a catalyst to obtain macroporous polystyrene resins containing organotransition metals. The distribution of the metal acetylide complexes in the modified macroporous resins was determined by an electron probe microanalyzer. A gradient in the transition metal distribution was observed in any case of the modified resins. The stability of the organotransition metal complexes in the polymer matrix could be compared with a low molecular weight analogous complex quantitatively.     

Thermoswitching property in TCNQ salts of ionenes containing poly(ethylene oxide) segments

Ionene polymers characterized by the alternating structure of ionene and crystalline poly(ethylene oxide) (PEO) segments were prepared as a function of PEO segment size. A microstructure of these ionenes and their 7,7,8,8-tetracyanoquinodimethane (TCNQ) salts were investigated with x-ray diffraction patterns, thermal scanning behavior, and polarizing micrographs. On the basis of this microstructure, the change in resistivity with temperature was studied. In Arrhenius' plots of the resistivity the simple salts in which the spherulites consisting of the PEO segments were observed showed a sharp decrease in resistivity with a rise in temperature [critical temperature resistor (CTR)] at about the melting point of the PEO segments, whereas the other simple salts in which the spherulites were not observed showed linear temperature dependence. The switching properties were confirmed similarly in repetitive heating/cooling cycles. This CTR characteristic was attributed to an increase in continuity in the conduction paths by melting spherulites. The apparent switching properties were not observed in the complex salts.     

Sensing lymphoma cells based on a cell-penetrating/apoptosis-inducing/electron-transfer peptide probe

To electrochemically sense lymphoma cells (U937), we fabricated a multifunctional peptide probe that consists of cell-penetrating/apoptosis-inducing/electron-transfer peptides. Electron-transfer peptides derive from cysteine residue combined with the C-terminals of four tyrosine residues (Y₄). A peptide whereby Y₄C is bound to the C-terminals of protegrin 1 (RGGRLCYCRRRFCVCVGR-NH₂) is known to be an apoptosis-inducing agent against U937 cells, and is referred to as a peptide-1 probe. An oxidation response of the peptide-1 probe has been observed due to a phenolic hydroxyl group, and this response is decreased by the uptake of the peptide probe into the cells. To improve the cell membrane permeability against U937 cells, the RGGR at the N-terminals of the peptide-1 probe was replaced by RRRR (peptide-2 probe). In contrast, RNRCKGTDVQAWY₄C (peptide-3 probe), which recognizes ovalbumin, was constructed as a control. Compared with the other probes, the change in the peak current of the peptide-2 probe was the greatest at low concentrations and occurred in a short amount of time. Therefore, the cell membrane permeability of the peptide-2 probe was increased based on the arginine residues and the apoptosis-inducing peptides. The peak current was linear and ranged from 100 to 1000 cells/ml. The relative standard deviation of 600 cells/ml was 5.0% (n = 5). Furthermore, the membrane permeability of the peptide probes was confirmed using fluorescent dye.