Nutritional status modulates rat liver cytochrome P450 arachidonic acid metabolism

Alterations in nutritional status affect hepatic cytochrome P450 levels. Since cytochromes P450 participate in the metabolism of arachidonic acid, we hypothesized that changes in liver P450 arachidonic acid metabolism occur during fasting and refeeding. Male Fisher 344 rats were either fed, fasted 48 hr (F48), fasted 48 hr and then refed 6 hr (F48/R6), or fasted 48 hr and then refed 24 hr (F48/R24). F48 rats had reduced body weight, increased plasma beta-hydroxybutyrate, and reduced plasma insulin compared with the other groups. Although there was no significant change in total liver P450 content, there was a significant 20%, 48%, and 24% reduction in total hepatic microsomal arachidonic acid metabolism in F48, F48/R6, and F48/R24 rats, respectively, compared with fed rats. Epoxygenase activity decreased by 28%, 51%, and 26% in F48, F48/R6, and F48/R24 rats, respectively. In contrast, omega-1 hydroxylase activity increased by 126% in F48 rats compared with fed rats. Immunoblotting revealed that levels of CYP2C11 protein were markedly reduced, whereas levels of CYP2E1 protein were markedly increased in the F48 and F48/R6 groups. In contrast, levels of CYP1A1, CYP1A2, CYP2B1, CYP2J3, CYP4A1, and CYP4A3 were unchanged with fasting/refeeding. Northern blots revealed that levels of CYP2C11 mRNAs were decreased, whereas CYP2E1 mRNAs were increased in F48 and F48/R6 rats. Recombinant CYP2C11 metabolized arachidonic acid primarily to epoxides with preference for the 14(S),15(R)-, 11(R), 12(S)-, and 8(S),9(R)- epoxyeicosatrienoic acid enantiomers. We conclude that (1) nutritional status affects hepatic microsomal arachidonic acid metabolism, (2) reduced epoxygenase activity in F48 and F48/R6 rats is accompanied by decreased levels of CYP2C11, (3) increased omega-1 hydroxylase activity is accompanied by augmented levels of CYP2E1, and (4) the effects of fasting on CYP2C11 and CYP2E1 expression occur at the pretranslational level.     

The Effect of Resonant Acoustic Oscillations on Heat and Mass Transfer Rates in a Convection Air Dryer

There has been much debate in recent years as to the effectiveness of enhancing heat and mass transfer rates with resonant acoustic oscillations in industrial equipment such as boilers, dryers, calciners, gasifiers, and others. This article will briefly discuss the theoretical background of acoustic drying, the setup of the experimental apparatus used to investigate the feasibility of acoustically enhanced drying, the results of these experiments, and, finally, some conclusions drawn from this work. The theoretical discussion focuses on the use of the quasi-steady assumption to estimate the potential for enhancing the heat and mass transfer rate to and from the material using acoustic oscillations. The experimental work reported focuses on the successful application of acoustical oscillations to drying a cellulose sponge, which is a material that readily transports moisture to its surface where it can be effectively dried. Also reported is the unsuccessful application of acoustic oscillations to the drying of polyethylene terephthalate, which is a saturated, thermoplastic, polyester resin made by condensing ethylene glycol and terephthalic acid and is commonly used in the manufacture of plastic food and drink containers. Reasons for success and failure in each case are discussed along with the implications of these to the successful application of acoustic oscillations to future drying applications.     

Railroad tracks: a potential source of ignition in hazardous ( classified) locations

This article uses a case history to illustrate how railroads are a potential source of ignition in hazardous (classified) locations. It will provide an overview of industry standards, design requirements, and operating procedures to ensure proper isolation, bonding, and grounding of railroad tracks and railcars at loading/unloading facilities.     

Ultrashort intense-field optical vortices produced with laser-etched mirrors

We introduce a simple and practical method to create ultrashort intense optical vortices for applications involving high-intensity lasers. Our method utilizes femtosecond laser pulses to laser etch grating lines into laser-quality gold mirrors. These grating lines holographically encode an optical vortex. We derive mathematical equations for each individual grating line to be etched, for any desired (integer) topological charge. We investigate the smoothness of the etched grooves. We show that they are smooth enough to produce optical vortices with an intensity that is only a few percent lower than in the ideal case. We demonstrate that the etched gratings can be used in a folded version of our 2f-2f setup [Opt. Express 19, 7599 (2005)] to compensate angular dispersion. Finally, we show that the etched gratings withstand intensities of up to 10(12) W/cm(2).     

Drying oil-in-water Pickering emulsions to make redispersible powders

We report on the formation of powder by drying oil-in-water emulsions stabilized by silanised silica nanoparticles. Drying was achieved by spraying fine droplets (up to a hundred micrometres in diameter) of the emulsions into a chamber of hot, flowing air. We show that the surfaces of droplets of the emulsions become enriched with nanoparticles as the water evaporates in the drying chamber. Controlling the relative amounts of oil and particles in the droplets being dried is the key to encapsulating the oil drops within the powder. Dried Pickering emulsions containing up to 40 wt% encapsulated oil that could be dispersed in water as drops of the same size as in the original emulsion were produced.     

Late-emerging reading disabilities.

Literacy, language, and cognitive skills were compared for 35 4th-5th graders with early-identified reading disabilities (RD), 31 with late-identified RD (first seen after 3rd grade), and 95 normally achieving students. Late-identified reading deficits were heterogeneous; some children were weak in both comprehension and word-level processing, whereas others had deficiencies in 1 component of reading but were unimpaired in the other. Although most reading skill deficits were about as severe for late- as for early-identified RD, and profiles of associated characteristics were similar, few of the former had yet been identified by their schools. Third-grade achievement, retrospectively examined, had been higher for the group with late-identified RD, suggesting that their reading difficulties were not just late identified but actually late emerging. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Effect of Resonant Acoustic Oscillations on Heat and Mass Transfer Rates in a Convection Air Dryer

There has been much debate in recent years as to the effectiveness of enhancing heat and mass transfer rates with resonant acoustic oscillations in industrial equipment such as boilers, dryers, calciners, gasifiers, and others. This article will briefly discuss the theoretical background of acoustic drying, the setup of the experimental apparatus used to investigate the feasibility of acoustically enhanced drying, the results of these experiments, and, finally, some conclusions drawn from this work. The theoretical discussion focuses on the use of the quasi-steady assumption to estimate the potential for enhancing the heat and mass transfer rate to and from the material using acoustic oscillations. The experimental work reported focuses on the successful application of acoustical oscillations to drying a cellulose sponge, which is a material that readily transports moisture to its surface where it can be effectively dried. Also reported is the unsuccessful application of acoustic oscillations to the drying of polyethylene terephthalate, which is a saturated, thermoplastic, polyester resin made by condensing ethylene glycol and terephthalic acid and is commonly used in the manufacture of plastic food and drink containers. Reasons for success and failure in each case are discussed along with the implications of these to the successful application of acoustic oscillations to future drying applications.     

Redesign of the substrate specificity of human cathepsin D: the dominant role of position 287 in the S2 subsite

Interest in the active site specificity of human cathepsin Dstems from the search for specific therapeutic agents againstmany of the sequentially and structurally homologous membersofthe aspartic proteinase family. The work presented here examinedone amino acid in the cathepsin D sequence, located in the S₂subsite, which contributes substantially to the specificityof enzyme-Ugand interactions at the enzyme active site. Previousstudies reported on the specificity of binding and catalysisby native and recombinant human cathepsin D explored throughkinetic studies using a systematic series of synthetic substrates.Utilizing a rulebased molecular model of human cathepsin D,Met287 was suggested as a candidate for mutagenesis to furtherexplore selectivity within the S₂ subsite of the cathepsin Dactive site. Met287 mutant derivatives of human cathepsin Dwere designed, expressed and characterized in kineticstudies.Native cathepsin D accommodates large hydrophobic residues inthe P₂ position of a substrate; positively charged residuesin P₂ are not favorable for catalysis.It was demonstrated thataltering Met287 of human cathepsin D to more polar amino acidsproduced active mutant enzymes with significantly altered substratespecificity.     

Evaluating the effects of behavioral realism in embodied agents

Designers of embodied agents constantly strive to create agents that appear more human-like, with the belief that increasing the human-likeness of agents will improve users’ interactions with agents. While designers have focused on visual realism, less attention has been paid to the effects of agents’ behavioral realism on users’ responses. This paper presents an empirical study that compared three theories of agent realism: Realism Maximization Theory, Uncanny Valley Theory, and Consistency Theory. Results of this study showed that people responded best to an embodied agent when it demonstrated moderately realistic, inconsistent behavior. These results support Uncanny Valley Theory and demonstrate the powerful influence of agent behavior on users’ responses.