Pulsed Electron-Beam Ionization of Humid Air and Humid Air/Toluene Mixtures: Time-Resolved Cationic Kinetics and Comparisons with Predictive Models

The technique of pulsed electron-beam high-pressure mass spectrometry wasused to investigate the sequential cationic chemistry in humid air streamsat 4.2×10² Pa and 380 K. The system was then modeled usingthe ACUCHEM program, incorporating thirty-five reactions taken from theformulations given in Part I of the new National Institute of Standards andTechnology (NIST) Chemical Kinetics Database for Humid Air Plasmas. Theresulting temporal ion profiles were found to be in qualitative agreementwith the laboratory data. Analogous pulsed electron-beam measurements werealso carried out with humid air samples containing low levels of toluene,and these results were also reproduced qualitatively by a model incorporatingforty-eight reactions after the inclusion of an unexpected, but crucial,channel involving the reaction of an intermediate air-generated cluster ionwith toluene. The benefits of laboratory validation of predictive databasesin systems for which the literature data are incomplete are emphasized.     

X-ray spectroscopic study of the electronic structure of visible-light responsive N-, C- and S-doped TiO2

The electronic origins of the visible-light response of N-, C- and S-doped TiO₂ have been studied using X-ray absorption, X-ray emission, and X-ray photoelectron spectroscopies. New electronic states are observed in the bulk band gap, above the valence band edge of pure TiO₂, which can be directly related to the visible-light absorption of the N-, C- and S-doped TiO₂ materials.     

Irreversible thermodynamics of non-uniform insulating ferromagnets

Two types of damping are commonly applied to describe ferromagnets at the phenomenological level: one by Landau and Lifshitz, and the other by Gilbert. This work successively applies the methods of irreversible thermodynamics to insulators, insulating paramagnets, and uniform insulating ferromagnets, in the last case uniquely obtaining Landau–Lifshitz damping. These methods are then applied to non-uniform insulating ferromagnets, for which new, non-current-related, spin fluxes and spin torques appear. These may be relevant to the dynamics of magnets in confined geometries, where boundary conditions impose complex non-trivial textures. Study of systems with very large damping might help distinguish between the two proposed forms of damping.     

Recent Developments and Applications of Three-Phase Partitioning for the Recovery of Proteins

Three-phase partitioning (TPP) is rapidly developing as a novel bioseparation technique for the separation and purification of biomolecules. TPP has been applied in a wide range of applications including enzyme stability and enhancement of its catalytic activity. The partitioning into three phases is mainly dependent on the concentration of alcohol and salt used. TPP provides high enzyme recovery and can be utilized along with external techniques such as ultrasound, microwave assisted, microaffinity ligand-facilitated and also ionic-liquid based. This technique has attracted interest in the large scale recovery of proteins from crude feedstocks or fermentation broths. In this review, the basic principles, refolding of proteins using TPP, key design variables of TPP, types of TPP, applications of TPP in food industry as well as the challenge of TPP were analyzed. The work presented in this review will be beneficial for further researches in TPP or related separation techniques.     

Carboxylation and esterification of functionalized arylcopper reagents

Functionalized arylcopper reagents have been produced in good yields at 25 degrees C from activated copper and the corresponding functionalized aryl iodides without the need of traditional organolithium or Grignard precursors. These organocopper compounds will undergo carboxylation with CO(2) to form the corresponding copper benzoates. In turn, these salts can be acidified to produce the functionalized aryl acids or treated with appropriate alkyl halides in the presence of a dipolar aprotic solvent to generate the corresponding aryl esters. This methodology permits the formation of functionalized organic acids and esters that could not be generated by the carboxylation of organomagnesium compounds.     

Efficient light harvesting by using green Zn-porphyrin-sensitized nanocrystalline TiO2 films

A series of novel zinc metalloporphyrins, cyano-3-(2'-(5',10',15',20'-tetraphenylporphyrinato zinc(II))yl)-acrylic acid (Zn-3), 3-(trans-2'-(5',10',15',20'-tetraphenylporphyrinato zinc(II))yl)-acrylic acid (Zn-5), 2-cyano-5-(2'-(5',10',15',20'-tetraphenylporphyrinato zinc(II))yl)-penta-2,4-dienoic acid (Zn-8), 4-(trans-2'-(2' '-(5' ',10' ',15' ',20' '-tetraphenylporphyrinato zinc(II))yl)ethen-1'-yl))-1,2-benzenedicarboxylic acid (Zn-11), and 2-cyano-3-[4'-(trans-2' '-(2' '-(5' ',10' ',15' ',20' '-tetraphenylporphyrinato zinc(II))yl) ethen-1' '-yl)-phenyl]-acrylic acid (Zn-13) were synthesized and characterized by using various spectroscopic techniques. Density functional theory (DFT) and time-dependent DFT (TDDFT) calculations show that key molecular orbitals (MOs) of porphyrins Zn-5 and Zn-3 are stabilized and extended out onto the substituent by pi-conjugation, causing enhancement and red shifts of visible transitions and increasing the possibility of electron transfer from the substituent. The porphyrins were investigated for conversion of sunlight into electricity by constructing dye-sensitized TiO(2) solar cells using an I(-)/I(3)(-) electrolyte. The cells yield close to 85% incident photon-to-current efficiencies (IPCEs), and under standard AM 1.5 sunlight, the Zn-3-sensitized solar cell demonstrates a short circuit photocurrent density of 13.0 +/- 0.5 mA/cm(2), an open-circuit voltage of 610 +/- 50 mV, and a fill factor of 0.70 +/- 0.03. This corresponds to an overall conversion efficiency of 5.6%, making it the most efficient porphyrin-sensitized solar cell reported to date.     

Synthesis of 3-[(1-aryl)aminomethyl]indoles

We report the novel synthesis of various highly functionalized 3-arylaminomethyl indoles. This synthetic approach makes use of the directing ability of a bulky tert-butyldimethylsilyl-protecting group, which directs the condensation of an array of aromatic tosylaldimines specifically into the 3-position of the indole nucleus. The reactions, which occur under relatively mild conditions, afford the desired products in moderate yields. Prior to selective cleavage of the protecting group, the functionalized protected indoles also serve as attractive substrates for many future organic transformations.     

Modal Interpretations and Relativity

A proof is given, at a greater level of generality than previous no-go theorems, of the impossibility of formulating a modal interpretation that exhibits serious Lorentz invariance at the fundamental level. Particular attention is given to modal interpretations of the type proposed by Bub.