A classification of orbits admitting a unique invariant measure

We consider the space of countable structures with fixed underlying set in a given countable language. We show that the number of ergodic probability measures on this space that are $S_{\infty }$-invariant and concentrated on a single isomorphism class must be zero, or one, or continuum. Further, such an isomorphism class admits a unique $S_{\infty }$-invariant probability measure precisely when the structure is highly homogeneous; by a result of Peter J. Cameron, these are the structures that are interdefinable with one of the five reducts of the rational linear order $(\mathbb{Q},<)$.     

Bioactive Chemical Constituents of Cladiella Species

From the methanolic extract of Cladiella sp., collected from the Andaman Island, India, a new sesquiterpene, cladidiol ( 2 ), and three known diterpenes, cladiellaperoxide ( 3 ), (6E)‐2α,9α‐epoxyeunicella‐6,11(12)‐dien‐3β‐ol ( 4 ), and polyanthellin A ( 5 ) were isolated. The structures of these compounds were established by extensive spectroscopic studies. Compound 2 exhibited modest acetylcholinesterase‐inhibition activity, and compounds 3 – 5 showed antibacterial activities against Streptococcus pyogenes, Escherichia coli, and Pseudomonas aeruginosa.     

The physical properties of linear chain systems. I. The optical spectra of [(CH3)4N]NiCl3, Cs(Mg,Ni)Cl3, CsNiCl3, RbNiCl3 and CsNiBr3

The single crystal spectra of pure CsNiCl₃, CsNiBr₃, RbNiCl₃, and [(CH₃)₄]NiCl₃, and the single crystal spectrum of CsNiCl₃ diluted in CsMgCl₃ have been measured to 5°K. The spectra of the magnetically concentrated materials show a number of anomalously intense maxima. These are interpreted in terms of cooperative interactions.     

Structure and growth kinetics of the oxidation process of Fe(001) whisker surfaces over a 10-decade pressure range

Fe(001) surfaces of whiskers of good crystalline quality were oxidized in a pressure range from 10^? 7 mbar to 1 bar at different temperatures. Epitaxial Fe₃O₄ and FeO thin films with negligible strain were grown depending on the oxidation temperatures. The kinetics of the oxide thickness growth was measured and compared with the predictions of the Fromhold–Cook theory for oxidation of metals. Some discrepancies were found and a possible explanation is presented.     

Resolution and quantification of arginine,monomethylarginine, asymmetric dimethylarginine,and symmetric dimethylarginine in plasma using HPLC with internal calibration

N^G,N^G‐dimethyl‐l ‐arginine (asymmetric dimethylarginine, ADMA),N^G‐monomethyl‐l ‐arginine (l ‐NMMA) and N^G,N^G’‐dimethyl‐l ‐arginine (symmetric dimethylarginine, SDMA) are released during hydrolysis of proteins containing methylated arginine residues. ADMA and l ‐NMMA inhibit nitric oxide synthase by competing with l ‐arginine substrate. All three methylarginine derivatives also inhibit arginine transport. To enable investigation of methylarginines in diseases involving impaired nitric oxide synthesis, we developed a high‐performance liquid chromatography (HPLC) assay to simultaneously quantify arginine, ADMA, l ‐NMMA and SDMA. Our assay requires 12 μL of plasma and is ideal for applications where sample availability is limited. We extracted arginine and methylarginines with mixed‐mode cation‐exchange columns, using synthetic monoethyl‐l ‐arginine as an internal standard. Metabolites were derivatized with ortho‐phthaldialdeyhde and 3‐mercaptopropionic acid, separated by reverse‐phase HPLC and quantified with fluorescence detection. Standard curve linearity was ≥0.9995 for all metabolites. Inter‐day coefficient of variation (CV) values were ≤5% for arginine, ADMA and SDMA in human plasma and for arginine and ADMA in mouse plasma. The CV value for l ‐NMMA was higher in human (10.4%) and mouse (15.8%) plasma because concentrations were substantially lower than ADMA and SDMA. This assay provides unique advantages of small sample volume requirements, excellent separation of target metabolites from contaminants and validation for both human and mouse plasma samples. © 2015 The Authors Biomedical Chromatography published by John Wiley & Sons, Ltd.     

Structural and spectral characterization of two 1-phenyl-1,2-propanedione bis{N(4)-alkylthiosemicarbazones}

1-phenyl-1,2-propanedione bis{N(4)-methyl- and {N(4)-ethylthiosemicarbazone}, H₂Pm4M and H₂Pm4E, respectively, have been prepared, studied spectroscopically (¹H NMR, ultraviolet and infrared) and their crystal structures solved. Intermoiety hydrogen bonding does not occur in H₂Pm4M and H₂Pm4E, in contrast to the analogous bis{N(4)-thiosemicarbazones} prepared from 1-phenylglyoxal. The two thiosemicarbazone moieties are on the opposite side of the carbon–carbon backbone, but the N(4)Hs intramolecularly hydrogen bond to the imine nitrogen for each moiety.     

Novel copolymers of styrene. 3. Some ring-substituted propyl 2-cyano-3-phenyl-2-propenoates

Novel trisubstituted ethylenes, ring-substituted propyl 2-cyano-3-phenyl-2-propenoates, RPhCH?C(CN)CO₂C₃H₇ (where R is 2-C₆H₅CH₂O, 3-C₆H₅CH₂O, 4-C₆H₅CH₂O, 4-CH₃COO, 3-CH₃CO, 4-CH₃CONH, 2-CN, 3-CN, 4-CN, 4-(CH₃)₂N, 4-(C₂H₅)₂N) were prepared and copolymerized with styrene. The monomers were synthesized by the piperidine catalyzed Knoevenagel condensation of ring-substituted benzaldehydes and propyl cyanoacetate, and characterized by CHN analysis, IR, ¹H and ¹³C-NMR. All the ethylenes were copolymerized with styrene (M₁) in solution with radical initiation (ABCN) at 70°C. The compositions of the copolymers were calculated from nitrogen analysis and the structures were analyzed by IR, ¹H and ¹³C-NMR. Decomposition of the copolymers in nitrogen occurred in two steps, first in the 200–500°C range with residue (2.7–8.6% wt.), which then decomposed in the 500–800°C range.