Phosphine functionalized polyaniline nanostructures

We study the problem of limited functionalization options for polyaniline through the surface attachment of phosphine coupling reagents. These studied linkers are P(CH₂OH)₃ and Ph₂PCH₂OH, and are attached to both conventional and nanostructured polyaniline. Additionally, model compounds are considered, extending the scope of our analysis. The successful attachment results indicate the potential for further functionalization, using the hydroxymethyl terminal groups of the phosphines for primary and secondary amine chemistry. These results should enable the development of sensitive and molecule-specific polyaniline-based devices.     

Radiorecovery Activity of Dicopper(II) Tetrakis(3,5-Diiso propylsalicylate) Includes Recovery of Radiation-Induced Loss of Body Mass and Impaired Mouse Locomotion

Dicopper(II) tetrakis(3,5-diisopropylsalicylate), [Cu(II)(2)(3,5-DIPS)(4)], is effective in increasing survival of lethally irradiated mice when it is administered after irradiation. The possibility that this radiorecovery activity might also facilitate recovery from radiation-induced impaired increase in body mass and locomotion was examined. Cu(II)(2)(3,5-DIPS)(4) was used to treat LD 50/30 gamma irradiated female C57BL/6 mice after irradiation. A dose of 0, 5, 10, or 20 mumol Cu(II)(2) (3, 5-DIPS)(4) /kilogram of body mass was administered subcutaneously 3 hrs after LD 50/30 irradiation and change in body mass and locomotor activity measured daily throughout the 30 day post-irradiation period. Treatment with 5, 10, or 20 mumol Cu(II)(2) (3,5-DIPS)(4) /kg of body mass increased survival, which was statistically significant for the 10 mumol /kg of body mass-treated group compared to the vehicle-treated group (P<0.05), significantly (P<0.05) increased recovery of locomotion from days 13 to 15 post-irradiation onward for all treated groups compared to vehicle-treated mice, and increased recovery of body mass gain from day 14 onward for the 20 mumol /kg of body mass-treated group (P<0.001) and day 21, although not statistically significant, for the 10 mumol /kg of body mass-treated group. There were no statistically significant differences between the increase in survival, recovered increase in body mass, and recovered increase in locomotion for mice treated with 10 mumol or 20 mumol Cu(II)(2)(3,5-DIPS)(4) /kg on day 30 post-irradiation. It is concluded that Cu(II)(2)(3,5-DIPS)(4) in addition to increasing survival of irradiated mice increases the rate of recovery of radiation-induced decrease in body mass and locomotion.     

A three-parameter Kozeny–Carman generalized equation for fractal porous media

The Kozeny–Carman equation is a traditional permeability–porosity relationship which has been used in many models of real problems related to flows in porous media. In spite of this, some limitations of this well-known equation has motivated the conception of different versions, specialized for particular applications. In the present article, we deduce a three-parameter Kozeny–Carman equation obtained from a fractal structure involving the specific surface and the tortuosity of the porous medium. Here, a theoretical analysis indicates that the new equation is capable to generalize several models existent in the literature. Besides, parameter estimations fitting experimental data of different materials show that the present model can be used to describe the relationship between permeability and porosity of many materials, such as sandstones, sisal fiber mat and glass fiber fabrics.     

Residential energy consumption across different population groups: comparative analysis for Latino and non-Latino households in USA

Residential energy cost is an important part of the household budget and could vary significantly across different population groups in many countries. In the United States, many studies have analyzed household fuel consumption by fuel type, including electricity, natural gas, fuel oil, and liquefied petroleum gas (LPG), and by geographic areas. Past research has also demonstrated significant variation in residential energy use across various population groups, including white, black, and Latino. However, our research shows that residential energy demand by fuel type for Latinos, the fastest growing population group, has not been explained by economic and non-economic factors in any statistical model in public domain. The purpose of this paper was to discuss energy demand and expenditure patterns for Latino and non-Latino households in hhe United States as a case example of analyzing residential energy consumption across different population groups in a country. The linear expenditure system model developed by Stone and Geary is the basis of the statistical model developed to explain fuel consumption and expenditures for Latino households. For comparison, the models are also developed for non-Latino, black, and non-black households. These models estimate energy consumption of and expenditures for electricity, natural gas, fuel oil, and LPG by various households at the national level. Significant variations in the patterns of these fuels consumption for Latinos and non-Latinos are highlighted. The model methodology and results of this research should be useful to energy policymakers in government and industry, researches, and academicians who are concerned with economic and energy issues related to various population groups in their country.     

TBT causes regime shift in shallow lakes

Tributyltin (TBT) is an organotin compound used since the early 1960s as a biocide in boat antifouling paints. Its use has been linked to a host of negative effects in marine ecosystems including malformations and imposex in Mollusca and acute toxicity in many other aquatic animals. Yet, the consequences of TBT use in freshwaters are largely unknown. Here, for the first time we reveal that TBT may have caused hitherto unsuspected damage to freshwater ecosystems. Through an analysis of dated sediment cores collected from a system of recreationally boated, shallow lakes, we show that first evidence of TBT is associated with a dramatic loss of submerged vegetation and associated diverse animal communities. Cause and effect are difficult to unravel in our study. However, we hypothesize that TBT, through reducing populations of grazing organisms in lakes already affected by eutrophication, promoted the replacement of macrophytes by phytoplankton, ultimately leading to a regime shift in the ecosystem. Our findings may have parallels in freshwater ecosystems all over the world.     

Experimental observation of the improvement in MTF from backthinning a CMOS direct electron detector

The advantages of backthinning monolithic active pixel sensors (MAPS) based on complementary metal oxide semiconductor (CMOS) direct electron detectors for electron microscopy have been discussed previously; they include better spatial resolution (modulation transfer function or MTF) and efficiency at all spatial frequencies (detective quantum efficiency or DQE). It was suggested that a ‘thin’ CMOS detector would have the most outstanding properties [1], [2] and [3] because of a reduction in the proportion of backscattered electrons. In this paper we show, theoretically (using Monte Carlo simulations of electron trajectories) and experimentally that this is indeed the case.     

Hydrolysis of fish oils containing polymers of triacylglycerols by pancreatic lipasein vitro

Fish oils containing different levels of polymers of triacylglycerols formed during autoxidation were incubated with pancreatic lipase to establish whether these polymers are substrates for lipase hydrolysis. With oils containing low amounts (less than 4%) of triacylglycerol polymers as substrates, both triacylglycerols and polymers of triacylglycerols were almost completely hydrolyzed, and fatty acid monomers and monoacylglycerols were the major lipid products. Under the same incubation conditions, some triacylglycerols remained intact when highly oxidized oils containing 20 or 30% triacylglycerol polymers were the substrate. The fatty acid composition of these residual triacylglycerols was almost identical to that of triacylglycerols present at the start of the assay. When fish oil containing 30% triacylglycerol polymers was incubated with the lipase, the component triacylglycerols and polymers of triacylglycerols were hydrolyzed at similar rates, and fatty acid dimers were detected as a product. It is concluded that the high molecular weight polymers of triacylglycerols present in oxidized fish oils can be hydrolyzed by pancreatic lipasein vitro.     

Effect of localised antibiotic infusions applied to the teat-canal and teat sinus at drying-off on mastitis in the dry-period and at calving

An experiment using three New Zealand herds and a total of 632 cows, examined the effect of localised prophylactic treatments with antibiotic at drying-off on the incidence of new intramammary infection during the dry period and at calving. Antibiotic was infused either into the teat canal (0.22 g of dry-cow formulation) or the teat sinus (3.1 g of lactating-cow formulation) of uninfected quarters to eliminate any bacteria present in these locations at the last milking of lactation. These treatments were compared with a negative control (nil treatment) and a positive antibiotic control (infusion of 3.6 g of dry-cow formulation). All antibiotic formulations used the same active ingredient, sodium cloxacillin. No significant reduction in new dry period clinical mastitis was observed for the two localised treatments whereas the positive control treatment achieved 100% reduction in new clinical mastitis compared with untreated control quarters. A 41% reduction (P < 0.05) in new Streptococcus uberis infections at calving was associated with the teat canal antibiotic treatment, compared with an 82% reduction (P < 0.001) for the positive antibiotic control. Both localised treatments showed a reduced incidence of new intramammary infection (P < 0.001) when pooled across periods and pathogens. Teats receiving either the teat canal antibiotic treatment or a full infusion of long acting dry-cow antibiotic had a lower incidence of open teat canals (P < 0.05) at 3 weeks after drying-off.