Neutron activation analysis of bottom and fly oil ashes

The concentrations of 25 elements in 7 oil ash samples were determinedby computerized systematic instrumental absolute neutron activation analysis.In the oil ash samples, the following mean concentrations (in ppm) of elementswere found: Al: 39531, As: 109, Ba: 1391, Ca: 29701, Ce: 295, Co: 1294, Cr:1485, Cs: 7.9, Dy: 4.5, Eu: 1.2, Fe: 53094, Ga: 146, Hf: 2.2, La: 1534, Mn:547, Na: 40277, Sb: 360, Sc: 2.3, Sm: 21, Sr: 674, Ta: 15.8, V: 130548, W:4.1, Yb: 0.9 and Zn: 3125. These findings were compared with the concentrationsof elements found in coal ash samples. The concentrations of Co, Na and Vwere significantly higher in the oil ash samples, while the concentrationof Sc was lower. The purpose of this study has been to determine the backgroundlevels of different elements in oil ash, in order to evaluate its potentialimpact on the environment.     

Characterization of polysaccharides having activity on the reticuloendothelial system from the rhizome of Curcuma longa

Three polysaccharides, named ukonan A, ukonan B and ukonan C, were isolated from the rhizomes of Curcuma longa L. They were homogeneous on electrophoresis and gel chromatography, and showed remarkable reticuloendothelial system-potentiating activity in a carbon clearance test. They are composed of L-arabinose: D-xylose: D-galactose: D-glucose: L-rhamnose: D-galacturonic acid in the molar ratios of 12:4:12:1:4:10 (ukonan A), 12:4:12:1:2:4 (ukonan B) and 8:3:6:14:2:3 (ukonan C), in addition to small amounts of peptide moiety. Methylation analysis, carbon-13 nuclear magnetic resonance and periodate oxidation studies indicated the structural features of ukonan B, the major one in terms of the activity. It has acidic arabino-galactan type structural units.     

Constituents of the seed of Malva verticillata. VI. Characterization and immunological activities of a novel acidic polysaccharide

A novel acidic polysaccharide, designated as MVS-VI, was isolated from the seeds of Malva verticillata L. It was homogeneous on electrophoresis and gel chromatography, and its molecular mass was estimated to be 26000. It is composed of L-arabinose: D-xylose: D-galactose: D-glucose: L-rhamnose: D-galacturonic acid in the molar ratio of 30: 15: 20: 3: 2: 10, in addition to small amounts of peptide moiety. Methylation analysis, carbon-13 nuclear magnetic resonance and periodate oxidation studies indicated its structural features to have mainly acidic alpha-arabino-3,6-beta-galactan type structural units. MVS-VI showed significant reticuloendothelial system-potentiating activity in a carbon clearance test, and it possesses remarkable anti-complementary activity.     

A Shock Tube Study of H Atom Addition to Cyclopentene

We report shock tube studies of the kinetics of H atom addition to cyclopentene and modeling of the subsequent decomposition of cyclopentyl. Hydrogen atoms were generated with thermal precursors in dilute mixtures of cyclopentene and a reference compound in argon. Addition of H to the double bond leads to a cyclopentyl radical that rapidly ring opens and decomposes to ethene and allyl radical. The process was monitored by postshock gas chromatographic analysis of ethene and rate constants determined relative to H atom displacement of methyl from 1,3,5‐trimethylbenzene (135TMB). At 863–1167 K and 160–370 kPa, we find and, with , we obtain Using experimental values of about 3:1 for the ratio of C─C to C─H beta scission in cyclopentyl radicals and a corresponding transition‐state‐theory/Rice‐Ramsberger‐Kassel‐Marcus (TST/RRKM) model, the high‐pressure rate expression for addition of H to cyclopentene at 863–1167 K is derived as Combined with literature results from lower temperatures and a fitted TST model, the rate expression between 298 and 2000 K is determined as Results are compared with related systems. Near 1000 K, our data require a minimum value of 1.5 for branching between beta C─C and C─H scission in cyclopentyl radicals to maintain established trends in H addition rates. This conflicts with current computed values and those used in existing kinetics models of cyclopentane combustion. We additionally report and discuss minor observed channels in the decomposition of cyclopentene, including formation of 1,4‐pentadiene, (E/Z)‐1,3‐pentadiene, 1,3‐butadiene, and the direct elimination of H₂ from cyclopentene to give cyclopentadiene.     

Binary and Ternary Complexes Involved in the Systems Methioninehydroxamic Acid - Glycylglycine - Ni(II) or Cu(II) Ions

The formation constants of binary and ternary complexes involved in the systems methioninehydroxamic acid (MX), glycylglycine (GG) and Cu(II) or Ni(II) were determined by pH-metric titration in aqueous solution at an ionic strength (I)= 0.15 M NaCl) and T = 25°C. Ternary species of the type (MX : GG : Ni(II) or Cu(II) : H) = (1 : 1 : 1 : r), (2 : 1 : 1 : r) and (1 : 2 : 1 : r) exist in the pH range ～3 to ～10. Differential pulse polarography (DPP) was used to follow complex formation and to study the reduction properties of these metal ions in the presence of MX, and GG. The metal oxidation states were more stabilized in the ternary systems than in the binary systems except for a few Ni(II) systems. Spectral studies in the UV-Vis-nIR were used to monitor the presence of ternary species in the Ni(II) and Cu(II) systems. In addition, EPR studies were also used to record the magnetic properties of the binary and ternary species in the Cu(II) systems.     

交联聚苯乙烯微球固载2,2,6,6-四甲基哌啶氮氧自由基的催化氧化性能与机理

将交联聚苯乙烯(CPS)微球表面固载有2,2,6,6-四甲基哌啶氮氧自由基(TEMPO)的非均相催化剂微球(TEMPO/CPS)与过渡金属盐相结合,构成复合催化剂体系,用于分子氧对肉桂醇的氧化过程的研究。 分别采用高价金属离子氧化性比硝酸根NO3-更弱和更强的两类过渡金属盐为助催化剂,与微球TEMPO/CPS构成组合催化剂,深入探索研究了其催化性能与催化机理。 研究结果表明,几种过渡金属盐(如Fe、Cu、Mn、Co盐)与微球TEMPO/CPS形成的复合催化剂,可有效地催化分子氧对肉桂醇的氧化过程,将其转化为唯一的产物肉桂醛。 以过渡金属硝酸盐为助催化剂,当硝酸盐结构中对应的高价态(氧化态)金属离子的氧化性比NO3-离子弱时(如Fe(NO₃)₃与Cu(NO₃)₂),正负离子共同发挥助催化作用;当硝酸盐结构中对应的高价态(氧化态)金属离子的氧化性比NO3-离子强时,比如Co(NO₃)₂与Mn(NO₃)₂对应的Co(Ⅲ)与Mn(Ⅲ)离子,金属离子单独发挥助催化作用,NO3-离子不起作用。 实验结果表明,对于肉桂醇的分子氧催化氧化,在几种过渡金属盐中,Fe(NO₃)₃作为最适宜的助催化剂,温和条件下(55 ℃、常压O₂),可高效地将肉桂醇转化为肉桂醛,转化率为92%。     

Thermal and Photochemical Isomerization of Tetraaryl Tetrakis(trifluoromethyl)

The isomerization of tetraaryl tetrakis(trifluoromethyl)[4]radialenes was studied. When type II (all-Z) isomers of 5,6,7,8-tetraaryl-5,6,7,8-tetrakis(trifluoromethyl)[4]radialenes were heated in tetralin at 170-200 degrees C, isomerization occurred to give mixtures of four [4]radialenes in a ratio of ca. I:II:III:IV = 1:10:5:1. However, when the isomeric mixtures were heated in the solid state at the same temperature, selective isomerization took place to give type II isomers in good selectivity (>91%). Upon irradiation with light, the type II isomers first isomerized to mixtures of the four [4]radialene isomers (I:II:III:IV = 2:2:48:48) and then rearranged to cyclobuta[b]naphthalenes via a 6pi-electrocyclic reaction followed by 1,3-hydrogen migration.     

Optimal design of powdered nanosized oxides of high surface area and porosity using a citric acid aided route, with special reference to ZnO

Polybasic hydroxy and amino carboxylic acid routes offer great advantages for the synthesis of powdered oxide nanomaterials of high surface area and porosity. A detailed analysis of the state-of-the-art in the field is performed, and some unresolved problems are discussed. Precursors of zinc oxide with the Zn²⁺:citric acid:ethylene glycol ratio of 1:1:0, 1:2:0, 1:4:0, 1:2:1, 1:2:2, 1:2:4 and 1:2:10 are studied. Their thermal decomposition is analyzed using DTA, IR, XRD, SEM, TEM methods, and porosity measurements in order to determine the component ratio and heating temperature enabling one to obtain the target oxide of the smallest particle size, the highest surface area, and the maximal amount of micropores. It is found that such a goal can be reached with the precursor of the 1:2:0 component ratio thermally treated at 400 °C.     

Characterization of two polysaccharides having activity on the reticuloendothelial system from the root of Glycyrrhiza uralensis

Two polysaccharides, called glycyrrhizans UA and UB, were isolated from the root of Glycyrrhiza uralensis Fischer. They were homogeneous on electrophoresis and gel chromatography, and showed reticuloendothelial system-potentiating activity in a carbon clearance test. Glycyrrhizan UA is composed of L-arabinose: D-galactose: L-rhamnose: D-galacturonic acid in the molar ratio of 20:14:1:3, and glycyrrhizan UB is composed of L-arabinose: D-galactose: D-glucose: L-rhamnose: D-galacturonic acid in the molar ratio of 12:10:1:10:20, in addition to small amounts of O-acetyl groups and peptide moiety, respectively. About 10% (glycyrrhizan UA) and 35% (glycyrrhizan UB) of the D-galacturonic acid residues exist as the methyl esters. Methylation analysis, carbon-13 nuclear magnetic resonance and periodate oxidation studies indicated their structural features.     

Hydrogen electrosorption in nanocrystalline Ti-based alloys

The electrochemical behavior in alkaline solution (1 M NaOH) of nanocrystalline Ti:Ru:Fe:O (2:1:1:2) prepared by high-energy ball milling was studied over its whole electroactivity domain, with a particular emphasis on the hydrogen evolution reaction (her). Comparison has also been made with nanocrystalline Ti:Ru:Fe (2:1:1) and a mixture of Ti:TiO:Ru:Fe₂O₃ (3/2:1/2:1:1/2). It was shown by cyclic voltammetry, open circuit potential decay and chronopotentiometry measurements that hydrogen absorption in the electrode material occurs during hydrogen discharge. The electrochemical behavior of nanocrystalline Ti:Ru:Fe:O (2:1:1:2) closely follows that of Ti:Ru:Fe (2:1:1), but differs radically from that of Ti:TiO:Ru:Fe₂O₃ (3/2:1/2:1:1/2). This is due to the fact that the former two compounds contain a significant fraction of B2 phase (59 and 97 wt.%, respectively), while the latter does not. In steady state conditions, the ratio H/B2 phase in nanocrystalline Ti:Ru:Fe:O (2:1:1:2) is 0.15, about 1.6 times less than that for the O-free nanocrystalline compound. The coefficient of diffusion of hydrogen in nanocrystalline Ti:Ru:Fe:O (2:1:1:2) is 2.6×10⁻¹³ cm² s⁻¹, more than three times less than that in nanocrystalline Ti:Ru:Fe (2:1:1). The difference between the hydrogen absorption characteristics of both nanocrystalline compounds are tracked down to the fact that their B2 phases have different stoichiometries.     

Detection of Al(III) and Ga(III) complexes with morin by electrospray ionization mass spectrometry.

The Al(III) and Ga(III) complexes formed by morin (M) in aqueous solution were investigated by means of electrospray ionization mass spectrometry (ESI-MS). In the full scan mass spectra, Al:M showed 1:2 and 2:3 stoichiometric ratios. When (S)-N-acetylserine methyl ester (Ser), as a partial mimic of the serine residue in silk, was added to Al:M and Ga:M complexes in aqueous solution, the mass spectra of Ser:Al:M showed 1:1:1 and 1:1:2 stoichiometric ratios. The patterns of the mass spectra of Ga:M and Ser:Ga:M complexes were similar to those for the corresponding Al(III) complexes. Calculated heats of formation of potential structures of the complexes, with and without bound water, were obtained using semiempirical PM3 calculations.     

Annellation effects in the perylene and coronene series

Naphtho(2′:3′, 2:3)perylene (VIII), dinaphtho(2′:3′, 2:3); (2″:3″, 8:9)perylene (VII), anthraceno(1′:4′, 1:12)perylene(IV), 1:12-benzonaphtho(2″:3″, 2:3)perylene(II), 1:12-benzonaphtho (2″:3″, 4:5)perylene (III) and 1:12-benzodinaphtho(2″:3″, 2:3); (2″“:3″”,8:9)perylene (XV) were synthesized. There are two different annellation effects in passing from 1:12-benzoperylene (I) to II or III resp., the one in naphthocoronene (V) lies in between these two effects. The annellation effect in the perylene series cannot be related to the molecular axes but is easily explained by the strict application of Robinsons aromatic sextet.     

Low-temperature liquid–liquid extraction of phenols from aqueous solutions with hydrophilic mixtures of extractants

The volume ratios in acetonitrile–ethyl acetate (90 : 10, 95 : 5), acetonitrile–isopropanol–ethyl acetate (70 : 15 : 15, 80 : 5 : 15), and isopropanol–1-butanol (50 : 50) mixtures were determined. Their mixing with water (1 : 1) and storage at–10°C led to partitioning into two immiscible liquid phases without formation of the ice phase. The mixtures were shown to be useful as hydrophilic extractants in low-temperature liquidliquid extraction of phenol from aqueous solutions.     

Thiopegan derivatives—XVI Synthesis of 10:11-thiopegan derivatives containing a saturated thiazole moiety and of their related compounds

2-Methyl-6-chloro-10:11-thiopegene-9:4-one, 2:7-dimethyl-10:11-thiopegene-9:4-one and the corresponding methylene bases have been synthesized. These methylene thiopegans furnish corresponding isomeric 2-methyl derivatives on acid treatment. 2-Bromomethyl-7-methyl-10:11-thiopega-2:9-diene-4-one has been condensed with piperidine and diethylamine to incorporate the therapeutically important basic moiety in these compounds. New routes to the synthesis of various substituted 2-methyl-10:11-thiopegans and 2-bromomethyl-10:11-thiopega-2:9-diene-4-ones have been developed with a view to improve their yields.     

High-throughput screening assay for the quantification of Cer d18:1/16:0, d18:1/24:0, d18:1/24:1, d18:1/18:0, d18:1/14:0, d18:1/20:0, and d18:1/22:0 in HepG2 cells using RapidFire mass spectrometry

Ceramides are known to be involved in various biological processes with their physiological levels elevated in various disease conditions such as diabetes, Alzheimer's, atherosclerosis. To facilitate the rapid screening of Cer d18:1/16:0, d18:1/24:0, d18:1/24:1, d18:1/18:0, d18:1/14:0, d18:1/20:0, and d18:1/22:0 inhibition in HepG2 cells, a RapidFire coupled to tandem mass spectrometry (RF–MS/MS) method has been developed. The RF platform provides an automated solid-phase extraction system that gave a throughput of 12.6 s per sample to an MS/MS system using electrospray ionization under the positive ion mode. Chromatographic separation of Cer d18:1/16:0, d18:1/24:0, d18:1/24:1, d18:1/18:0, d18:1/14:0, d18:1/20:0, and d18:1/22:0 was achieved using a ternary gradient on C₈ type E cartridge. The MS/MS ion transitions monitored were 538.2 → 264.2, 650.7 → 264.2, 648.6 → 264.2, 566.4 → 264.2, 510.4 → 264.2, 594.4 → 264.2, 622.5 → 264.2, and 552.3 → 250.2 for Cer d18:1/16:0, d18:1/24:0, d18:1/24:1, d18:1/18:0, d18:1/14:0, d18:1/20:0, d18:1/22:0, and the internal standard (Cer d17:1/18:0), respectively. The RF–MS/MS methodology showed an excellent performance with an average Z′ value of 0.5–0.7. This is the first report of an RF–MS/MS assay for screening of ceramides which is amenable for high-throughput screening.     

Mechanism of change in enantiomer migration order of enantioseparation of tartaric acid by ligand exchange capillary electrophoresis with Cu(II) and Ni(II)-D-quinic acid systems

The mechanism of change in the enantiomer migration order (EMO) of tartarate on ligand exchange CE with Cu(II)- and Ni(II)-D-quinic acid systems was investigated thoroughly by circular dichroism (CD) spectropolarimetry. The (13) C NMR spectra of solutions containing D-quinate (pH 5.0) with Cu(II) or Ni(II) revealed the coordination of carboxylate and hydroxyl groups on D-quinate. The D-quinic acid concentration dependence of the CD spectra at a fixed Cu(II) concentration at pH 5.0 indicates that the 1:1, 1:2 and 1:3 Cu(II)-D-quinate complexes were formed with an increase in the concentration of D-quinic acid. The CD spectral behavior revealed that D-tartarate is selectively coordinated to the 1:1 complex to give the 1:1:1 Cu(II)-D-quinate-D-tartarate ternary complex while L-tartarate is selectively bound to the 1:2 and 1:3 complexes to form the 1:2:1 ternary complex. In the Ni(II)-D-quinic acid system, it became apparent that the 1:2 Ni(II)-D-quinate complex is mainly formed in the wide range of D-quinic acid concentration at pH 5.0 and D-tartarate is selectively coordinated to the 1:2 complex to form the 1:2:1 ternary complex. The change in EMO of tartarate on ligand exchange CE was explainable by the change in coordination selectivity for D- and L-tartarates in the Cu(II)- and Ni(II)-D-quinic acid systems depending on the compositions of the complexes formed in BGE.     

Detailed profiles of 7-O-acyl esters in plankton and shellfish from the Portuguese coast

In bivalve mollusks from the Portuguese coast contaminated by diarrhetic shellfish poisoning (DSP), most of the parent toxins, okadaic acid (OA) or dinophysistoxin-2 (DTX2), are found esterified, and toxicity assessment is only performed after an alkaline hydrolysis step to recover the parent molecules in their free form. The presence of 7-O-acyl esters with fatty acids (FAs) has already been confirmed previously in Mytilus galloprovincialis and Donax trunculus samples. This paper reports the presence of acyl esters in a wider range of estuarine and offshore bivalve species found by direct analysis in LC-MS. The total of acyl esters found in each species represented the percentages commonly found by hydrolysis in those species in previous years, justifying the majority of the esters commonly found in shellfish. This implies that any diol esters remaining after digestion of toxic microalgae would represent only a minor contribution to the ester's contents. Esters with C14:0, C16:0, C16:1, C20:5 and C22:6 FAs were the most abundant, followed by esters with C18:0, C18:1, C18:2, C18:3 and C18:4. This is the first report of OA and DTX2 esters with odd FAs: C15:0, C17:0, C17:1, and probably a branched FA: iso-C16:0. Esters with iso-C16:0 where found in high percentages particularly in two species of estuarine clams, where they represented 13-34% of total esters found. Esters were also found in plankton, predominantly with C16:0. Total esters in plankton were not higher than 10%, not enough to justify per se the high levels found in bivalves.     

Serum fatty acid profiles and potential biomarkers of ankylosing spondylitis determined by gas chromatography–mass spectrometry and multivariate statistical analysis

Ankylosing spondylitis (AS) is a common chronic inflammatory rheumatic disease. Early and accurate detection is essential for effective disease treatment. Recently, research has focused on genomics and proteomics. However, the associated metabolic variations, especially fatty acid profiles, have been poorly discussed. In this study, the gas chromatography–mass spectrometry (GC‐MS) approach and multivariate statistical analysis were used to investigate the metabolic profiles of serum free fatty acids (FFAs) and esterified fatty acids (EFAs) in AS patients. The results showed that significant differences in most of the FFA (C12:0, C16:0, C16:1, C18:3, C20:4, C20:5, C22:5 and C22:6) and EFA (C12:0, C16:1, C18:0, C18:1, C18:2, C18:3, C20:4 and C22:6) concentrations were found between the AS patients and healthy controls (p < 0.05). Principal component analysis and partial least squares discriminant analysis were performed to classify the AS patients and controls. Additionally, FFAs C20:4, C12:0, C18:3 and EFAs C22:6, C12:0 were confirmed as potential biomarkers to identify AS patients and healthy controls. The present study highlights that differences in the serum FFA and EFA profiles of AS patients reflect the metabolic disorder. Moreover, FFA and EFA biomarkers appear to have clinical applications for the screening and diagnosis of AS. Copyright © 2014 John Wiley & Sons, Ltd.     

Behaviour of the thiodipropionic complex of In(III) and U(VI) at the DME in aqueous and aqueous methanolic solutions

The complexation of In(III) and U(VI) with thiodipropionic acid has been investigated polarographically in water and water-methanol solutions at 30 +/- 0.1 degrees . All the chelates belong to polaro-graphically reversible systems. With indium(III), complexes with metal to ligand ratios of 1:1, 1:2, 1:3 and 1:4 are found at pH 4.8. Uranium(VI) is found to form three successive complexes with metal to ligand ratios of 1:1,1:2 and 1:3 in 0.1M HCl, with 0.1M KCl as supporting electrolyte.     

Effect of methane on magnetron sputtering graphite target deposited films and tribological properties of a-C:H:Ti/a-C:H friction pairs

In this study, we prepared a-C:H films with different nanostructures at different methane flow rates. The effect of the methane flow rate on the tribological properties of 440 steel/a-C:H friction pairs and a-C:H:Ti/a-C:H friction pairs in an atmospheric environment was studied by a reciprocating friction machine. The results show that there is no relationship between the tribological properties of 440 steel/a-C:H friction pair and methane flow rate. The tribological performance of the a-C:H:Ti/a-C:H friction pair was greatly improved. In particular, in the friction pair of a-C:H:Ti/a-C:H with a methane flow rate of 20 sccm, superlubricity is shown, and the wear rate is only 4.04 × 10⁻⁹ mm³/Nm. After tribological experiments, Raman spectroscopy, XPS, and other characterization methods were used to study the relationship between the nanostructure and tribological properties of a-C:H:Ti films and a-C:H prepared with different methane flow rates. This study is great significance to the application of a-C:H:Ti/a-C:H friction pair in mechanical parts under atmospheric environment.