Citrus pulp as a dietary source of antioxidants for lactating holstein cows fed highly polyunsaturated Fatty Acid diets.

The effects of feeding pelleted citrus pulp (PCP) as a natural antioxidant source on the performance and milk quality of dairy cows fed highly polyunsaturated fatty acid (FA) diets were evaluated. Four lactating Holstein cows were assigned to a 4×4 Latin-square. Treatments, on a dry matter (DM) basis, were i) control diet; ii) 3% soybean oil; iii) 3% soybean oil and 9% PCP and; iv) 3% soybean oil and 18% PCP. When cows fed on citrus pulp, the DM intake tended to decrease. The total tract apparent digestibility of DM and ether extract decreased when cows fed on the control diet compared to other diets. Cows fed PCP had higher polyphenols and flavonoids content and higher total ferric reducing antioxidant power (FRAP) in milk compared to those fed no pelleted citrus pulp. Cows fed 18% PCP showed higher monounsaturated FA and lower saturated FA in milk fat compared with cows fed the other diets. The lowest n-6 FA proportion was in milk fat from cows fed control. The present study suggests that pelleted citrus pulp added to 9% to 18% DM increases total polyphenols and flavonoids concentration, and the FRAP in milk.

The effect of co-impregnated acids on the performance of Zn-based broad spectrum respirator carbons.

Impregnated activated carbons (IACs) that are used in multi-gas respirator applications usually contain copper and/or zinc impregnants. Co-impregnating with properly selected acids can improve the distribution of the metallic impregnant on the carbon and improve the gas adsorption capacity of the IAC. In this work a comparative study of some common acids co-impregnated with a zinc nitrate (Zn(NO(3))(2)) precursor is performed. The IACs were heated in an inert atmosphere at temperatures which promoted the thermal decomposition of Zn(NO(3))(2) to zinc oxide (ZnO). The gas adsorption properties of the IACs were tested using ammonia (NH(3)), sulphur dioxide (SO(2)) and hydrogen cyanide (HCN) challenge gases. Powder X-ray diffraction (XRD) was used to identify the impregnant species present after heating and to study impregnant distribution. Gravimetric analysis was used to determine the impregnant loading, and help to identify the impregnant species after heating. The interactions between the co-impregnated acid and Zn(NO(3))(2) precursor during heating are discussed. The relationship between impregnant species and gas adsorption capacity is discussed.

The effect of heating temperature and nitric acid treatments on the performance of Cu- and Zn-based broad spectrum respirator carbons.

Impregnated activated carbons (IACs) that are used in broad spectrum gas mask applications have historically contained copper and/or zinc impregnants. The addition of an oxidizing agent, such as nitric acid (HNO(3)) can be useful in distributing the metallic impregnants uniformly on the activated carbon substrate. In this work, we study IACs prepared from copper nitrate (Cu(NO(3))(2)) and zinc nitrate (Zn(NO(3))(2)) precursors as a function of HNO(3) content present in the impregnating solution and as a function of heating temperature. The gas adsorption capacity of the IACs was determined by dynamic flow testing using sulfur dioxide (SO(2)), ammonia (NH(3)), hydrogen cyanide (HCN) and cyclohexane (C(6)H(12)) challenge gases under dry and humid conditions. The thermal decomposition and distribution of the impregnant on the activated carbon substrate is studied using X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermal analysis techniques. Relationships between gas adsorption capacity, impregnant distribution and the species of surface impregnants are discussed.

A combinatorial approach to screening carbon based materials for respiratory protection.

A combinatorial materials science approach for the discovery of an impregnated activated carbon that can adsorb a wide variety of toxic gases (i.e. a multi-gas carbon) has been developed. This approach presently allows for the parallel preparation and investigation of 64-100 IAC samples at once increasing the rate of discovery of viable multi-gas carbons. Multi-gas carbons were prepared using a solutions handling robot and screened gravimetrically for their effectiveness as gas adsorbents. The method was validated using known gas adsorbent materials such as ZnCl(2), K(2)CO(3) and CuO-impregnated carbons. The calculated adsorption capacities and stoichiometric ratios of reactions for these known gas adsorbent materials, when evaluated using the combinatorial approach, was comparable to the values obtained using traditional methods of analysis. A library of samples prepared by combining various amounts of CuO and ZnO impregnants showed the expected decreasing trend in the calculated stoichiometric ratio of reaction with respect to increasing amount of impregnants added. The method is now ready to use to explore new systems of impregnated activated carbons.