Cytokine expression in mice exposed to diesel exhaust particles by inhalation. Role of tumor necrosis factor

Background  

Particulate air pollution has been associated with lung and cardiovascular disease, for which lung inflammation may be a driving mechanism. The pro-inflammatory cytokine, tumor necrosis factor (TNF) has been suggested to have a key-role in particle-induced inflammation.     

RECURSIVE ESTIMATION IN SWITCHING AUTOREGRESSIONS WITH A MARKOV REGIME

Abstract. A hidden Markov regime is a Markov process that governs the time or space dependent distributions of an observed stochastic process. We propose a recursive algorithm for parameter estimation in a switching autoregressive process governed by a hidden Markov chain. A common approach to the recursive estimation problem is to base the estimation on suboptimal modifications of Kalman filtering techniques. The main idea in this paper is to use the maximum likelihood method and from this develop a recursive EM algorithm.     

Carbon black nanoparticle instillation induces sustained inflammation and genotoxicity in mouse lung and liver

Background

Widespread occupational exposure to carbon black nanoparticles (CBNPs) raises concerns over their safety. CBNPs are genotoxic in vitro but less is known about their genotoxicity in various organs in vivo.

Methods

We investigated inflammatory and acute phase responses, DNA strand breaks (SB) and oxidatively damaged DNA in C57BL/6 mice 1, 3 and 28 days after a single instillation of 0.018, 0.054 or 0.162 mg Printex 90 CBNPs, alongside sham controls. Bronchoalveolar lavage (BAL) fluid was analyzed for cellular composition. SB in BAL cells, whole lung and liver were assessed using the alkaline comet assay. Formamidopyrimidine DNA glycosylase (FPG) sensitive sites were assessed as an indicator of oxidatively damaged DNA. Pulmonary and hepatic acute phase response was evaluated by Saa3 mRNA real-time quantitative PCR.

Results

Inflammation was strongest 1 and 3 days post-exposure, and remained elevated for the two highest doses (i.e., 0.054 and 0.162 mg) 28 days post-exposure (P < 0.001). SB were detected in lung at all doses on post-exposure day 1 (P < 0.001) and remained elevated at the two highest doses until day 28 (P < 0.05). BAL cell DNA SB were elevated relative to controls at least at the highest dose on all post-exposure days (P < 0.05). The level of FPG sensitive sites in lung was increased throughout with significant increases occurring on post-exposure days 1 and 3, in comparison to controls (P < 0.001-0.05). SB in liver were detected on post-exposure days 1 (P < 0.001) and 28 (P < 0.001). Polymorphonuclear (PMN) cell counts in BAL correlated strongly with FPG sensitive sites in lung (r = 0.88, P < 0.001), whereas no such correlation was observed with SB (r = 0.52, P = 0.08). CBNP increased the expression of Saa3 mRNA in lung tissue on day 1 (all doses), 3 (all doses) and 28 (0.054 and 0.162 mg), but not in liver.

Conclusions

Deposition of CBNPs in lung induces inflammatory and genotoxic effects in mouse lung that persist considerably after the initial exposure. Our results demonstrate that CBNPs may cause genotoxicity both in the primary exposed tissue, lung and BAL cells, and in a secondary tissue, the liver.     

Combined Hydrothermal Conversion and Vapor Transport Sintering of Ag‐Modified Calcium Phosphate Scaffolds

Two processing methods were successfully combined to obtain Ag‐modified calcium phosphate scaffolds with antibacterial properties: (i) hydrothermal conversion of macroporous biogenic carbonates and (ii) vapor transport sintering. Hydrothermal conversion of two precursor materials, i.e., coral skeletons and sea urchin spines, resulted in the pseudomorphic replacement of highly porous calcium carbonates by calcium phosphate scaffolds. Vapor transport sintering of these scaffolds within a reactive AgCl atmosphere facilitated near net‐shape processing accompanied by the condensation of finely dispersed Ag‐bearing particles over the scaffold's surface. Chemical and phase compositions were analyzed using WDXRF, XRD, and DRIFTS (FTIR), and the microstructure development was characterized by SEM and TEM imaging. The dissolution kinetics of Ag⁺ ions in aqueous solution was determined and growth inhibition experiments with Gram‐positive and Gram‐negative bacteria were performed to assess the antibacterial properties of Ag‐modified ceramics.     

A Spatial Multi-Criteria Analysis Approach for Locating Suitable Sites for Construction of Subsurface Dams in Northern Pakistan

Pakistan is an agricultural country with an increasing interest for hydropower. Water management problems such as sedimentation and evaporation have been of high concern for surface water reservoirs for many years. Therefore, groundwater storage through subsurface dams could be promising, especially considering the monsoon rainfall and seasonal river flows in Pakistan. The paper aims to develop and test a methodology to locate suitable sites for construction of subsurface dams using spatial multi-criteria analysis (SMCA) in the northern parts of Pakistan. For the study, spatial data on geology, slope, land cover, soil depth and topographic wetness index (TWI) was used. Two weighting techniques, i.e. the analytic hierarchy process (AHP) and the factor interaction method (FIM), were employed and compared. The sensitivity of the two methods as well as of the model parameters was analysed. The suitability map derived from AHP yielded about 3 % (16 km²) of the total area as most suitable, about 4 % (22 km²) as moderately suitable and about 0.8 % (5 km²) as least suitable. The suitability map derived from FIM identified about 2.7 % (14 km²) of the total area as most suitable, about 4 % (22 km²) as moderately suitable and about 1 % (7 km²) as least suitable. The sensitivity analyses suggested that AHP was a more robust weighting technique than FIM and that land cover was the most sensitive factor. The methodology presented here shows promising results and could be used in early planning to locate suitable sites for construction of subsurface dams.     

Enzyme activity of alpha-chymotrypsin after derivatization with phenolic compounds

Alpha-chymotrypsin was allowed to react with selected phenolic and related compounds (chlorogenic acid, m-, o-, p-dihydroxybenzene, p-benzoquinone). The derivatized enzymes obtained were characterized in terms of their activity. In vitro experiments illustrated that the enzymatic activity of the derivatives was adversely affected. The kinetics of the enzymatic reactions showed that the hydrolysis of selected food proteins becomes slower and the affinity of the enzyme to these substrates declined as measured by Michaelis-Menten constant and maximum velocity of the enzymatic reaction. This enzyme inhibition depended on the reactivity of the phenolic and related substances tested as well as on the degree of the derivatization. Further, influence of the enzyme-substrate ratio was also demonstrated. The effects of the derivatization are more pronounced with increasing concentration of the substrates.     

应用酶放大电极的免疫测定

该文评述了应用酶放大电极的免疫测定法的进展,从原理和应用两方面进行了探讨.着重介绍了作者所在实验室在90年代以来的相关工作.     

Comparing two burnout interventions: Perceived job control mediates decreases in burnout.

This quasi-experimental study compared the effects of two rehabilitation interventions on burnout and perceived job conditions during a 1-year intervention among female white-collar workers. The participatory intervention (n = 20), involving rehabilitation activities that focused on the individual as well as on individual-organizational levels, assessed exhaustion, cynicism and perceived job control during a 1-year period. Increased job control served as a mechanism through which exhaustion and cynicism decreased in this intervention. The traditional intervention (n = 32), involving rehabilitation activities focusing mainly on the individual level, resulted in a reduction in time pressures during one year. Furthermore, both interventions improved perceived workplace climate. Compared to the traditional approach, the participatory intervention was a more effective strategy for treating burnout. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The nature of active sites for the oxidation of methane on La-based perovskites

Highly crystalline, monophasic LaFeO₃ and LaCoO₃ perovskites, prepared by the explosion method, are shown to be heterogeneous at surface level. The outmost atomic layers of these perovskites contain high concentrations of carbonate-type species. Their specific activities for methane combustion are in fact identical to La₂O₂CO₃ and air-exposed La₂O₃. These results compared with pertinent data from the literature hint that surface heterogeneity may be often present in mixed oxides catalysts.     

A coulometric method for the determination of low peroxide values of fats and oils

The AOCS official method for the determination of peroxide values of fats and oils has been modified to perform more precise analyses, especially in the range of extremely low values (peroxide value <1). In the newly developed method presented here, the final titrimetric step of an iodometric method has been replaced by an electrochemical technique, based upon coulometric reduction of the iodine at an electrode maintained at a controlled potential. Using this method peroxide values down to 0.06 were determined with reasonable precision. Finally, the influence of different parameters on the peroxide value obtained was investigated.