Direct electron transfer of cytochrome P450 2B4 at electrodes modified with nonionic detergent and colloidal clay nanoparticles

A method for construction of biosensors with membranous cytochrome P450 isoenzymes was developed based on clay/detergent/protein mixed films. Thin films of sodium montmorillonite colloid with incorporated cytochrome P450 2B4 (CYP2B4) with nonionic detergent were prepared on glassy carbon electrodes. The modified electrodes were electrochemically characterized, and bioelectrocatalytic reactions were followed. CYP2B4 can be reduced fast on clay-modified glassy carbon electrodes in the presence of the nonionic detergent Tween 80. In anaerobic solutions, reversible oxidation and reduction is obtained with a formal potential between -0.292 and -0.305 V vs Ag/AgCl 1 M KCl depending on the preparation of the biosensor. In air-saturated solution, bioelectrocatalytic reduction currents can be obtained with the CYP2B4-modified electrode on addition of typical substrates such as aminopyrine and benzphetamine. This reaction was suppressed when methyrapone, an inhibitor of P450 reactions, was present. Measurement of product formation also indicates the bioelectrocatalysis by CYP2B4.     

Aerosol lidar intercomparison in the framework of the EARLINET project. 3. Raman lidar algorithm for aerosol extinction, backscatter, and lidar ratio

An intercomparison of the algorithms used to retrieve aerosol extinction and backscatter starting from Raman lidar signals has been performed by 11 groups of lidar scientists involved in the European Aerosol Research Lidar Network (EARLINET). This intercomparison is part of an extended quality assurance program performed on aerosol lidars in the EARLINET. Lidar instruments and aerosol backscatter algorithms were tested separately. The Raman lidar algorithms were tested by use of synthetic lidar data, simulated at 355, 532, 386, and 607 nm, with realistic experimental and atmospheric conditions taken into account. The intercomparison demonstrates that the data-handling procedures used by all the lidar groups provide satisfactory results. Extinction profiles show mean deviations from the correct solution within 10% in the planetary boundary layer (PBL), and backscatter profiles, retrieved by use of algorithms based on the combined Raman elastic-backscatter lidar technique, show mean deviations from solutions within 20% up to 2 km. The intercomparison was also carried out for the lidar ratio and produced profiles that show a mean deviation from the solution within 20% in the PBL. The mean value of this parameter was also calculated within a lofted aerosol layer at higher altitudes that is representative of typical layers related to special events such as Saharan dust outbreaks, forest fires, and volcanic eruptions. Here deviations were within 15%.     

Aerosol lidar intercomparison in the framework of the EARLINET project. 1. Instruments

In the framework of the European Aerosol Research Lidar Network to Establish an Aerosol Climatology (EARLINET), 19 aerosol lidar systems from 11 European countries were compared. Aerosol extinction or backscatter coefficient profiles were measured by at least two systems for each comparison. Aerosol extinction coefficients were derived from Raman lidar measurements in the UV (351 or 355 nm), and aerosol backscatter profiles were calculated from pure elastic backscatter measurements at 351 or 355, 532, or 1064 nm. The results were compared for height ranges with high and low aerosol content. Some systems were additionally compared with sunphotometers and starphotometers. Predefined maximum deviations were used for quality control of the results. Lidar systems with results outside those limits could not meet the quality assurance criterion. The algorithms for deriving aerosol backscatter profiles from elastic lidar measurements were tested separately, and the results are described in Part 2 of this series of papers [Appl. Opt. 43, 977-989 (2004)]. In the end, all systems were quality assured, although some had to be modified to improve their performance. Typical deviations between aerosol backscatter profiles were 10% in the planetary boundary layer and 0.1 x 10(-6) m(-1) sr(-1) in the free troposphere.     

Cobalt-containing catalysts for the high-temperature combustion of methane

Cobalt was supported on ZrO₂, La-doped ZrO₂ and La₂O₃ through atomic layer epitaxy (ALE) and wet impregnation. The rate data obtained at 770 K is compared with literature information about cobalt inserted in other matrixes. The ALE technique using ZrO₂ and La-doped ZrO₂ yielded the best cobalt-containing catalysts. Bulk and surface characterization techniques provided key clues to understand the origin of the large difference in catalytic activity reported for cobalt-containing formulations.     

A GC–MS-based metabonomic investigation of blood serum from irritable bowel syndrome patients undergoing intervention with acidified milk products

In the present study, the use of gas chromatography mass spectrometry (GC–MS)-based metabonomics to characterize blood serum in an intervention study of patients suffering from the common gastrointestinal disorder irritable bowel syndrome (IBS) was investigated. The patients included in the study consumed an acidified milk product with (n = 30) or without probiotics (n = 31) (Lactobacillus paracasei F19, Lactobacillus acidophilus LA-5 and Bifidobacterium lactis BB-12) for an 8-week period, and blood serum samples were collected before and after the intervention. Acidified milk is commonly used as a delivering vector for probiotics in commercial consumer settings. The serum samples were extracted and derivatized using N-Methyl-N-(trimethylsilyl) trifluoroacetamide (MSTFA), and GC–MS analysis was carried out. Multivariate data analysis including principal component analysis (PCA), orthogonal partial least squares-discriminant analysis (OPLS-DA), and S-plot was applied on the obtained GC–MS data, which revealed higher serum lactate, glutamine, proline creatinine/creatine, and aspartic acid levels and lower serum glucose levels after the intervention period for both treatment groups. Consequently, the present study indicated an effect of acidified milk consumption on the plasma metabolite profile, which was independent of a concomitant intake of probiotics. In addition, the present study demonstrates that GC–MS is a useful analytical technique for metabonomics studies of blood serum.     

Processing issues related to the bi-dimensional ionic conductivity of BIMEVOX ceramics

Bismuth vanadate, Bi₄V₂O₁₁, and its doped variations, Bi₄(Co_0.15V_0.85)₂O₁₁, Bi₄(Cu_0.1V_0.9)₂O₁₁, and Bi₄(Cu_0.05Ti_0.05V_0.90)₂O₁₁ are investigated with respect to relative processability and total conductivity. In conventionally prepared (pressure-less sintered) ceramic disks, the single-substitution compounds show signs of exaggerated grain growth with significant c-axis preferred orientation. The doubly substituted Bi₄(Cu_0.05Ti_0.05V_0.90)₂O₁₁ is found to have the widest processing window, resulting in sintered monoliths with the highest relative density and no preferred orientation. It also shows the highest conductivity (7 × 10 ⁻² (Ωcm) ⁻¹) at 500 °C, as measured by impedance spectroscopy. Activation energies for conduction of the four compounds are reported and found to be comparable to earlier study. Hot forged samples of Bi₄(Cu_0.05Ti_0.05V_0.90)₂O₁₁ are prepared for the first time, with only moderate texturing achieved. We assert that the lack of texture in Bi₄(Cu_0.05Ti_0.05V_0.90)₂O₁₁ is responsible for the higher conductivity measured through the sample thickness when compared to Bi₄(Co_0.15V_0.85)₂O₁₁, Bi₄(Cu_0.1V_0.9)₂O₁₁ and other related compounds.     

Catalytic Oxidation of Industrial Wastewater Under Mild Conditions

Cerium?Czirconia-supported ruthenium and activated carbon catalysts were used in catalytic wet air (CWAO) and wet peroxide (CWPO) oxidation of industrial wastewater. Both catalysts were active in the removal of TOC and COD from the wastewater. The degree of biodegradation of organic matter increased during CWAO. Therefore, the CWAO process could be considered as a potential pre-treatment process integrated with subsequent biological treatment to achieve the required level of purification of wastewater.     

Smoking reduction predicts cessation: longitudinal evidence from the Finnish adult twin cohort.

The aim of the study was to examine whether smoking reduction over a 6-year period (1975-1981) predicted smoking cessation 9 years later by 1990. The longitudinal data from three surveys over 15-year period among the Finnish adult twin cohort were used. The data were collected by postal surveys in 1975, 1981, and 1990, and the sample comprised 11,015 participants, of whom 2,443 were persistent current smokers in 1975 and 1981. Smoking cessation by 1990 was examined as the outcome measure. Nineteen percent reported having stopped smoking by 1990, corresponding to an approximate annual rate of smoking cessation of 2%. Those who had quit smoking by 1990 had larger decreases in smoking between 1975 and 1981. The odds ratio for quitting by 1990 increased with increasing levels of reduction in amount smoked between 1975 and 1981. This was found in both categorical and trend analyses, and when adjusting for age, sex and for amount of baseline smoking. The model among twin pairs discordant for cessation indicated that the association of smoking reduction with increased likelihood of cessation was independent of genetic or early shared family influences on smoking behavior. We conclude that smokers who are able to decrease the number of cigarettes smoked per day by at least 25% are more likely to quit later.     

Testing the effort-reward imbalance model among Finnish managers: The role of perceived organizational support.

The present study is aimed at examining the combined effects of effort-reward imbalance (ERI), overcommitment (OVC), and perceived organizational support (POS) on turnover intentions and work engagement, among Finnish managers (n = 1,301). Consequently, the study contributes to the research literature by examining how the ERI-outcomes relationship was dependent simultaneously on OVC and POS. The results showed that ERI × OVC × POS interaction was significant only for turnover intentions. The ERI-turnover intentions relationship was strongest under conditions of high OVC and low POS. In addition, the relationship between ERI and decreased work engagement, especially dedication, was strengthened among overcommitted managers, compared to their less committed counterparts. Altogether, the results indicate that interventions aimed at reducing turnover intentions and increasing work engagement by increasing ERI should consider OVC and POS. (PsycINFO Database Record (c) 2010 APA, all rights reserved)