Prime Lie Rings of Derivations of Commutative Rings

Let R be a 2-torsion free commutative ring with identity, and δ a nonzero derivation of R such that R is δ-prime. Then Rδ is a prime Lie ring and any nonzero ideal of Rδ contains an ideal of the form Jδ where J is a nonzero δ-ideal of R.     

Detailed Description of Pulse Isotopic Exchange Method for Analyzing Oxygen Surface Exchange Behavior on Oxide Ion Conductors

A novel pulse ¹⁸O-¹⁶O isotopic exchange (PIE) technique for measurement of the rate of oxygen surface exchange of oxide ion conductors was presented. The technique employs a continuous flow packed-bed micro-reactor loaded with the oxide powder. The isothermal response to an ¹⁸O-enriched pulse passing through the reactor, thereby maintaining chemical equilibrium, is measured by on-line mass spectrometry. Evaluation of the apparent exchange rate follows from the uptake of ¹⁸O by the oxide at given reactor residence time and surface area available for exchange. The developed PIE technique is rapid, simple and highly suitable for screening and systematic studies. No rapid heating/quenching steps are required to facilitate ¹⁸O tracer anneal or analysis, as in other commonly used techniques based upon oxygen isotopic exchange. Moreover, the relative distribution of the oxygen isotopologues ¹⁸O₂, ¹⁶O¹⁸O, and ¹⁶O₂ in the effluent pulse provides insight into the mechanism of the oxygen exchange reaction. The PIE technique has been demonstrated by measuring the exchange rate of selected oxides with enhanced oxide ionic conductivity in the range of 350?900 oC. Analysis of the experimental data in terms of a model with two consecutive, lumped steps for the isotopic exchange reaction shows that for mixed conductors Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3-δ(BSCF) and La₂NiO_4+δ the reaction is limited by the apparent rate of dissociative adsorption of O₂ molecules at the oxide surface. For yttria-stabilized zirconia (YSZ), a change-over takes place, from rate-limitations by oxygen incorporation below ∽800 oC to rate-limitations by O₂ dissociative adsorption above this temperature. Good agreement is obtained with exchange rates reported for these materials in literature.     

2-Isopropylbenzimidazole and 2-methylbenzimidazole as bulky proton sources: Stereoselective protonation and application to the synthesis of γ- and δ-lactones

2-Isopropylbenzimidazole and 2-methylbenzimidazole have been found to be effective bulky proton sources for stereoselective protonation of chiral enolate anions. 2-Isopropylbenzimidazole worked in the stereoselective protonation of the Birch reduction of chiral α,β-unsaturated imides. On the other hand, 2-methylbenzimidazole was found to be the best protonation reagent in the isomerization reaction of α,β-unsaturated imide into β,γ-unsaturated imide. The Birch reduction using 2-isopropylbenzimidazole realized a concise and stereoselective synthesis of δ-lactone 14, a sex pheromone of Macrocentrus grandii, while the isomerization reaction using 2-methylbenzimidazole was employed in the highly stereoselective synthesis of the γ-lactone intermediate in the synthesis of depsipeptide antibiotics. These bulky proton sources would be powerful tools to achieve a concise synthesis of natural products.     

Spin-polarized transport in a δ-doped magnetic-barrier nanostructure

We theoretically investigate the electron spin transport properties through a δ-doped magnetic-barrier nanostructure, which can be realized experimentally by depositing two identical ferromagnetic stripes with the opposite in-plane magnetization on the top of a semiconductor heterostructure in parallel configuration and by using atomic layer doping technique. The δ-doping dependent transmission, conductance and spin polarization are calculated exactly by analytically solving Schrödinger equation of the spin electron. It is found that the electronic spin-polarized behavior in this device can be manipulated by changing the weight and/or the position of the δ-doping. Therefore, such a device can be used as a controllable spin filter, which may be helpful for spintronics applications.     

Semi-preparative HPLC purification of δ-tocotrienol (δ-T3) from Elaeis guineensis Jacq. and Bixa orellana L. and evaluation of its in vitro anticancer activity in human A375 melanoma cells

In this work, we report a rapid and convenient HPLC-UV-DAD method for the isolation of δ-T3 on semi-preparative scale from two different vitamin E rich processed, commercially available products obtained from the fruits of Elaeis guineensis Jacq. (oil palm) and from the seeds of Bixa orellana L. (achiote tree). Chromatography was run using reverse phase (RP) C-18 columns and HPLC-grade acetonitrile as mobile phase. The purity of the isolated δ-T3, assessed by GC–MS and ¹H NMR was above 98%. The δ-T3 cytotoxic activity found in vitro against the proliferation of human A375 melanoma cells compared to that of the other δ-T3 free tocols mixture suggest its primary role in the experimental anticancer activity observed for palm oil derived products. Taken altogether, the results of this study highlight the importance of the application of suitable purification systems for the preparations of tocotrienols prior to their experimental or clinical testing.     

Syntheses and applications of enantiopure δ-amino acids and their precursors

Enantiopure unnatural homologated amino acids, whereby there is?>?1 carbon atom between the C- and N- termini have found great utility in a number of applications. The enantiopure syntheses of β-amino acids are well documented, as increasingly are those of γ-amino acids. δ-Amino acids on the other hand are much less well-studied despite reports of their potential utility. This review attempts to summarise strategies that have been adopted towards the enantioselective synthesis of δ-amino acids and their precursors (e.g. nitrile/nitro/azido/ester/alcohol etc) and where appropriate demonstrate their utility. Only systems which are all carbon between the two termini are considered and only those where the shortest route between any given C-termini and any given N-termini is four carbons long (i.e. lysine derivatives are not considered).     

Well-posedness of a class of perturbed optimization problems in Banach spaces

Let X be a Banach space and Z a nonempty subset of X. Let J:Z→R be a lower semicontinuous function bounded from below and p?1. This paper is concerned with the perturbed optimization problem of finding z₀∈Z such that ‖x−z₀p^‖+J(z₀)=infz∈Z{‖x−zp^‖+J(z)}, which is denoted by minJ(x,Z). The notions of the J-strictly convex with respect to Z and of the Kadec with respect to Z are introduced and used in the present paper. It is proved that if X is a Kadec Banach space with respect to Z and Z is a closed relatively boundedly weakly compact subset, then the set of all x∈X for which every minimizing sequence of the problem minJ(x,Z) has a converging subsequence is a dense Gδ-subset of X?Z₀, where Z₀ is the set of all points z∈Z such that z is a solution of the problem minJ(z,Z). If additionally p>1 and X is J-strictly convex with respect to Z, then the set of all x∈X for which the problem minJ(x,Z) is well-posed is a dense Gδ-subset of X?Z₀.     

Solvent-free heterogeneous organocatalysis: stereoselective isomerization of α,β-ynones to (E,E)-α,β-γ,δ-dienones catalyzed by polymer-supported tertiaryphosphines

Stereoselective isomerization of α,β-ynones was catalyzed by polymer-supported tertiaryphosphines under solvent-free conditions. (E,E)-α,β-γ,δ-Dienones were obtained with up to 93% isolated yields when JJ-TPP was employed.     

固体氧化物燃料电池Cr毒化La0.8Sr0.2MnO3-δ(LSM)阴极机理

从电化学阻抗谱和阴极极化等方面对Cr毒化La0.8Sr0.2MnO3-δ(LSM)阴极机理进行了研究.     

掺Y对PbWO4闪烁体的热释光影响

研究了纯PbWO₄和PbWO₄:Y晶体经γ射线辐照和可见光光照前后室温 以上的热释光.发现大剂量辐照后掺Y可以有效地抑制热释光的强度并使热释光峰移向高温, 说明掺Y有利于提高光输出的稳定性.可见光光照也会影响热释光并可以产生新的热释光峰, 这可能是由于光释电子(或空穴)被浅陷阱重新俘获或是光照后产生了新型色心的结果. 关键词： 4')" href="#">PbWO₄ 掺Y 热释光