Efficient synthesis of hydroxystyrenes via biocatalytic decarboxylation/deacetylation of substituted cinnamic acids by newly isolated Pantoea agglomerans strains

BACKGROUND: Decarboxylation of substituted cinnamic acids is a predominantly followed pathway for obtaining hydroxystyrenes—one of the most extensively explored bioactive compounds in the food and flavor industry (e.g. FEMA GRAS approved 4‐vinylguaiacol). For this, mild and green strategies providing good yields with high product selectivity are needed. RESULTS: Two newly isolated bacterial strains, i.e. Pantoea agglomerans KJLPB4 and P. agglomerans KJPB2, are reported for mild and effective decarboxylation of substituted cinnamic acids into corresponding hydroxystyrenes. Key operational parameters for the process, such as incubation temperature, incubation time, substrate concentration and effect of co‐solvent, were optimized using ferulic acid as a model substrate. With strain KJLPB4, 1.51 g L^?1 4‐vinyl guaiacol (98% yield) was selectively obtained from 2 g L^?1 ferulic acid at 28 °C after 48 h incubation. However, KJPB2 provided vanillic acid in 85% yield after 72 h following the oxidative decarboxylation pathway. In addition, KJLPB4 was effectively exploited for the deacetylation of acetylated α‐phenylcinnamic acids, providing corresponding compounds in 65–95% yields. CONCLUSION: Two newly isolated microbial strains are reported for the mild and selective decarboxylation of substituted cinnamic acids into hydroxystyrenes. Preparative‐scale synthesis of vinyl guaiacol and utilization of renewable feedstock (ferulic acid extracted from maize bran) have been demonstrated to enhance the practical utility of the process. Copyright © 2011 Society of Chemical Industry     

Preliminary evaluation of interfacial stability of surface modified porous methyl silsesquioxane by ion implantation for copper metallization scheme

Thin films of ultra-low-κ materials such as porous methyl silsesquioxane (MSQ) (κ=2.2) were implanted with argon 1×10¹⁶ cm⁻² dose at energies varying from 20 to 50 keV at room temperature. This work shows that the surface hardness of the porous films can be improved five times as compared to the as-deposited porous films by implanting Ar with 1×10¹⁶ cm⁻² doses at 20 keV, sacrificing only a slight increase (∼9%) in dielectric constant (e.g., from 2.2 to 2.4). The hardness persists after 450 °C annealing. In this current work, an ion implantation strategy was pursued to create a SiO₂-like surface on MSQ. The effects of implantation parameters on the barrier property and bulk stability of MSQ were then studied. The results reveal one possible route to attain the “zero barrier thickness” requirement for interconnects systems.     

The effect of intermediate layer on synthesis and gas permeation properties of NaA zeolite membrane

NaA zeolite membrane coating was successfully synthesized on an alumina porous disc by hydrothermal treatment. The effects of synthesis parameters, such as seeding condition (in situ, ex situ), synthesis time, synthesis stages, application of intermediate layer, etc., on membrane characteristics were investigated. Surface seeding accelerates the zeolite crystallization process on the support surface, and also enhances the formation of homogeneous NaA zeolite layer. But the main problem associated with membrane coating synthesis is crack formation. Formation of crack was reduced by applying intermediate layer, between the support surface and seed layer. A thin Boehmite layer was applied to the support surface before applying seed crystals to enhance the adherence between zeolite seed layer and boehmite layer by hydrogen bonding and also to increase the mechanical strength of the membrane layer. The quality of the membrane layer can be improved by employing the multi-stage coating methods. The permeance of O₂, N₂ decreased as kinetic diameter of gases increased, which shows the molecular sieving effect of the NaA membrane. The permselectivity of O₂/N₂ was 1.9–2.0. This value of permselectivity ratio is higher than Knudsen diffusion ratio 0.94; it was also confirmed the molecular sieving properties of synthesized NaA zeolite membrane.     

Just-in-time dynamic voltage scaling: Exploiting inter-node slack to save energy in MPI programs

Although users of high-performance computing are most interested in raw performance, both energy and power consumption have become critical concerns. As a result, improving energy efficiency of nodes on HPC machines has become important, and the prevalence of power-scalable clusters, where the frequency and voltage can be dynamically modified, has increased.     

Adaptive Execution of Jobs in Computational Grid Environment

In a computational grid, jobs must adapt to the dynamically changing heterogeneous environment with an objective of maintaining the quality of service. In order to enable adaptive execution of multiple jobs running concurrently in a computational grid, we propose an integrated performance-based resource management framework that is supported by a multi-agent system (MAS). The multi-agent system initially allocates the jobs onto different resource providers based on a resource selection algorithm. Later, during runtime, if performance of any job degrades or quality of service cannot be maintained for some reason (resource failure or overloading), the multi-agent system assists the job to adapt to the system. This paper focuses on a part of our framework in which adaptive execution facility is supported. Adaptive execution facility is availed by reallocation and local tuning of jobs. Mobile, as well as static agents are employed for this purpose. The paper provides a summary of the design and implementation and demonstrates the efficiency of the framework by conducting experiments on a local grid test bed.     

K-, CeO2-, and Mn-promoted Ni/Al2O3 catalysts for stable CO2 reforming of methane

Reforming of methane with carbon dioxide into syngas over Ni/γ-Al₂O₃ catalysts modified by potassium, MnO and CeO₂ was studied. The catalysts were prepared by impregnation technique and were characterized by N₂ adsorption/desorption isotherm, BET surface area, pore volume, and BJH pore size distribution measurements, and by X-ray diffraction and scanning electron microscopy. The performance of these catalysts was evaluated by conducting the reforming reaction in a fixed bed reactor. The coke content of the catalysts was determined by oxidation conducted in a thermo-gravimetric analyzer. Incorporation of potassium and CeO₂ (or MnO) onto the catalyst significantly reduced the coke formation without significantly affecting the methane conversion and hydrogen yield. The stability and the lower amount of coking on promoted catalysts were attributed to partial coverage of the surface of nickel by patches of promoters and to their increased CO₂ adsorption, forming a surface reactive carbonate species. Addition of CeO₂ or MnO reduced the particle size of nickel, thus increasing Ni dispersion. For Ni–K/CeO₂–Al₂O₃ catalysts, the improved stability was further attributed to the oxidative properties of CeO₂. Results of the investigation suggest that stable Ni/Al₂O₃ catalysts for the carbon dioxide reforming of methane can be prepared by addition of both potassium and CeO₂ (or MnO) as promoters.     

Interpreting the out-of-control signal in multivariate control chart — a comparative study

Interpretation of the out-of-control signal poses a persistent problem in multivariate control chart owing to the limitations of available general methods like Hotelling T². Many research papers address these problems and present alternative approaches to diagnose faults in out-of-control conditions and to help identify aberrant variables. This work reviews the different methods and attempts to make a comparative study of some of these methods viz. Mason, Tracy and Young method (Journal of Quality Technology 27:99–108, 1995), Murphy method (The Statistician 36:571–583, 1987), Hawkins method (Technometrics 33:61–75, 1991) and Doganaksoy, Faltin and Tucker method (Communications in Statistics — Theory and Methods 20:2775–2790, 1991). A simulation approach was taken to generate data on various out of control situation and to compare the powers of different targeted methods. In control sate was characterised by a multi-variate normal with standardised mean and variance assuming intra-class correlation structure. Data were generated for different values of correlation and various out of control situation with respect to the shift of mean in one, two or more variables. Due to the limitations of using average run length as a performance criterion especially in case of skewed distribution of run length it was decided to use power as a measure of comparison. Situations in which the particular method works satisfactorily were identified with respect to correlation structure and pattern of shift of mean.     

On the hazard function of Birnbaum-Saunders distribution and associated inference

In this paper, we discuss the shape of the hazard function of Birnbaum-Saunders distribution. Specifically, we establish that the hazard function of Birnbaum-Saunders distribution is an upside down function for all values of the shape parameter. In reliability and survival analysis, as it is often of interest to determine the point at which the hazard function reaches its maximum, we propose different estimators of that point and evaluate their performance using Monte Carlo simulations. Next, we analyze a data set and illustrate all the inferential methods developed here and finally make some concluding remarks.     

Conceptual knowledge in the interpretation of idioms.

The authors examined how people determine the contextual appropriateness of idioms. In Experiment 1, idioms referring to the same temporal stage of a conceptual prototype were judged to be more similar in meaning than idioms referring to different temporal stages. In Experiment 2, idioms in a prototypical temporal sequence were more meaningful than idioms in sentences that violated the temporal sequence. In Experiment 3, idioms referring to the same stage of a conceptual prototype were differentiable on the basis of conceptual information. The conceptual coherence between idioms and contexts facilitated the processing speed of idioms in Experiment 4. Experiment 5 showed that speakers can recover the underlying conceptual metaphors that link an idiom to its figurative meaning. Experiment 6 showed that the metaphoric information reflected in the lexical makeup of idioms also determined the metaphoric appropriateness of idioms in certain contexts. (PsycINFO Database Record (c) 2010 APA, all rights reserved)