Fabrication of flexible carbon nanotube field emitter arrays by direct microwave irradiation on organic polymer substrate

Carbon nanotubes (CNTs) were directly synthesized on flexible polymer substrates without damage of polymer by microwave irradiation. Cobalt was used as the catalysts, and the synthesis was done in the atmospheric pressure with an acetylene carbon source. Only 5 s was required for the synthesis of well-graphitized CNTs. Field emission measurements revealed that this flexible CNT field emitter array has a great potential for the flexible field emission displays (FEDs).     

A Comparison of Discriminant Analysis versus Artificial Neural Networks

Artificial Neural Network (ANN) techniques have recently been applied to many different fields and have demonstrated their capabilities in solving complex problems. In a business environment, the techniques have been applied to predict bond ratings and stock price performance. In these applications, ANN techniques outperformed widely-used multivariate statistical techniques. The purpose of this paper is to compare the ANN method with the Discriminant Analysis (DA) method in order to understand the merits of ANN that are responsible for the higher level of performance. The paper provides an overview of the basic concepts of ANN techniques in order to enhance the understanding of this emerging technique. The similarities and differences between ANN and DA techniques in representing their models are described. This study also proposes a method to overcome the limitations of the ANN approach, Finally, a case study using a data set in a business environment demonstrates the superiority of ANN over DA as a method of classification of observations.     

Biomonitoring of environmental pollution based on studies of trace elements in soil and crops

Most elemental concentrations in crops should be related to those in soil and other circumferential environments. In the present study, more than thirty minor and trace elements in soils and crops were determined by the use of ICP, XRF and NAA. Soil and crop samples were collected at eleven abandoned mine regions in Chungnam province located in the middle part of Korea. The elemental concentrations in soils were compared to the crustal mean concentrations in both Chungnam area and worldwide. The concentration ratios of the elements in soils and crop compartments were calculated and the distribution characteristics of each element were investigated between soil and crop compartments.     

Isolation and spectral characteristics of Ferric Iodide

Ferric iodide is isolated pure for the first time as a dark purple solid when a hexane solution of diiodotetracarbonyliron(II) and diiodine is exposed to actinic radiation. Its identity is confirmed by elemental analysis and quantitative conversion to the known tetraiodoferrate(III) by treatment with tetra-n-butylammonium iodide. Although persistent in the solid state, ferric iodide is readily decomposed in solution to ferrous iodide and 0.5 mol diiodine quantitatively.     

Minimization of MC1R selectivity by modification of the core structure of alpha-MSH-ND

BACKGROUND: Melanocortin, through its distinct receptor subtypes, has many different effects. Receptor-selective ligands are required to reduce the undesirable effects of melanocortin. To investigate which conformation is preferable to a given melanocortin receptor subtype, a structural and functional analysis of the ligand-receptor interactions was made by studying the biological activity, the nuclear magnetic resonance structures, and the patterns of the ligand-receptor interaction for each receptor subtype by homology modeling analysis. RESULTS: Among the several analogues examined, [Gln(6)]alpha-melanocyte-stimulating hormone (MSH)-ND was found to have 10000 times less biological activity than alpha-MSH-ND for the MC1R, whereas, the potencies of both oligopeptides were comparable in both the melanocortin-3 receptor (MC3R) and MC4R. [Gln(6)]alpha-MSH-ND exhibited a type I' beta-turn that was similar to the type I beta-turn structure of alpha-MSH-ND. However, a remarkable structural difference was observed with respect to the side chain orientations of the sixth and seventh residues of [Gln(6)]alpha-MSH-ND, which were found to be mirror images of alpha-MSH-ND. By homology modeling analysis, the His(6) of alpha-MSH-ND was found to interact with the TM2 regions of all three receptors (Glu(94) of MC1R, Glu(94) of MC3R, and Glu(100) of MC4R), but [Gln(6)]alpha-MSH-ND did not. The phenyl ring of the D-Phe(7) residue of [Gln(6)]alpha-MSH-ND revealed an interaction with the TM3 regions of both the MC3R and MC4R (Ser(122) of MC3R or Ser(127) of MC4R). However, in the MC1R, these serine residues corresponded to Val(122), which contains two methyl groups that induce steric hindrance with D-Phe(7) of [Gln(6)]alpha-MSH-ND. This is a possible explanation for the biological activity of [Gln(6)]alpha-MSH-ND for the MC1R being significantly lower than that for either the MC3R or MC4R. CONCLUSIONS: Minimization of the MC1R selectivity whilst preserving its comparable potency for both the MC3R and MC4R could be achieved by modifying the D-Phe(7) orientation of alpha-MSH-ND, while maintaining the 'type I beta-turn'-like structure.     

Indium-mediated consecutive 1,2-shift reaction and regioselective allylation of vinyl epoxides

Allyl indium, prepared from allyl bromide and indium metal in aprotic solvent, reacts with terminal vinyl epoxides at room temperature to afford various bishomoallyl alcohols in moderate to high yields via consecutive 1,2-shift reaction and regioselective allylation.     

Quantitative Determination of Octylonium in Human Plasma by LC–MS

The purpose of this investigation was to develop a method for measuring the concentration of octylonium in human plasma. Hydrochloric acid was added to the plasma samples before pretreatment to improve the stability of the octylonium. After liquid–liquid extraction with ethylacetate and isopropanol (10:1), the analytes were separated by chromatography on a reversed-phase C₁₈ column and detected by LC–MS–MS with electrospray ionization–ionization. The coefficient of variation for the precision of the assay was less than 10.1%, and the accuracy ranged from 98.0 to 106.5%. The limit of quantification or sensitivity was 0.2 ng mL⁻¹. This method was validated by measuring octylonium in the plasma of healthy human subjects after administration of a single 120-mg oral dose of octylonium bromide. Thus, a highly sensitive and accurate analytical method was developed to determine the concentration of octylonium in human plasma.     

Aminocyclopentadienyl ruthenium complexes as racemization catalysts for dynamic kinetic resolution of secondary alcohols at ambient temperature

Aminocyclopentadienyl ruthenium complexes, which can be used as room-temperature racemization catalysts with lipases in the dynamic kinetic resolution (DKR) of secondary alcohols, were synthesized from cyclopenta-2,4-dienimines, Ru(3)(CO)(12), and CHCl(3): [2,3,4,5-Ph(4)(eta(5)-C(4)CNHR)]Ru(CO)(2)Cl (4: R = i-Pr; 5: R = n-Pr; 6: R = t-Bu), [2,5-Me(2)-3,4-Ph(2)(eta(5)-C(4)CNHR)]Ru(CO)(2)Cl (7: R = i-Pr; 8: R = Ph), and [2,3,4,5-Ph(4)(eta(5)-C(4)CNHAr)]Ru(CO)(2)Cl (9: Ar = p-NO(2)C(6)H(4); 10: Ar = p-ClC(6)H(4); 11: Ar = Ph; 12: Ar = p-OMeC(6)H(4); 13: Ar = p-NMe(2)C(6)H(4)). The tests in the racemization of (S)-4-phenyl-2-butanol showed that 7 is the most active catalyst, although the difference decreased in the DKR. Complex 4 was used in the DKR of various alcohols; at room temperature, not only simple alcohols but also functionalized ones such as allylic alcohols, alkynyl alcohols, diols, hydroxyl esters, and chlorohydrins were successfully transformed to chiral acetates. In mechanistic studies for the catalytic racemization, ruthenium hydride 14 appeared to be a key species. It was the major organometallic species in the racemization of (S)-1-phenylethanol with 4 and potassium tert-butoxide. In a separate experiment, (S)-1-phenylethanol was racemized catalytically by 14 in the presence of acetophenone.     

Total synthesis of the CP-molecules (CP-263,114 and CP-225,917, phomoidrides B and A). 3. Completion and synthesis of advanced analogues

The completion of the total syntheses of the CP-molecules is reported. Several strategies and tactics, including the use of amide-based protecting groups for the homologated C-29 carboxylic acid and the use of an internal pyran protecting group scheme, are discussed. The endeavors leading to the design of new methods for the homologation of hindered aldehydes and to the isolation of a polycyclic byproduct (23), which inspired the development of a new series of reactions based on iodine(V) reagents, are described. In addition, the discovery and development of the LiOH-mediated conversion of CP-263,114 (1) to CP-225,917 (2) is described, and a mechanistic rationale is presented. Finally, a synthetic route to complex analogues of the CP-molecules harboring a maleimide moiety in place of the maleic anhydride is presented.