Tailoring the synthesis of stainless steel wire mesh-supported ZnO

The aim of this work was to synthesise different nanostructures of zinc oxide supported on a stainless steel wire mesh, using hydrothermal processes in which several conditions were applied. The effect of the different synthesis parameters on the final properties of the samples (yield and geometrical dimensions) were analysed and discussed. The ZnO nanomaterials obtained exhibit a homogeneous distribution over the metallic wire mesh, with mass yields in the range of 3–30 wt.%, a prismatic morphology with a hexagonal cross-section, lengths between 700 nm and 6 μm and widths in the 70 nm–2.3 μm range. These nanomaterials are intended to be applied in photocatalytic reactions and as catalyst supports.     

Esterification of Free Fatty Acids Using Layered Carboxylates and Hydroxide Salts as Catalysts

Layered lanthanum and copper(II) laurates were tested as catalysts for methanolic esterification of lauric acid (C₁₂). Factorial design evidenced a positive effect of reaction temperature and amount of catalyst on ester conversion, while the acid:alcohol molar ratio (MR) had a negative effect. With lanthanum laurate, 90.5% conversion was reached at 140???C with 10% catalyst and MR of 6:1. Although the highest conversion with copper(II) laurate converted 81.5% under the same conditions, results were better with a lower amount of catalyst (78% ester at 140???C with 2% catalyst and MR of 6:1). A calcium hydroxide succinate was also investigated showing better catalytic performance than the well-known CaO, under mild reaction conditions (120???C with 1% catalyst and MR of 3:1). Although layered carboxylates can be successively reused, the layered calcium hydroxide salt transformed into inactive CaCO₃ in the second reuse reaction.     

Application and evaluation of the method of ellipses for measuring the orientation of long,semi‐flexible fibers

The method of ellipses (MoE) is a common experimental technique utilized to quantitatively determine the orientation state of a population of rigid fibers within a fiber–polymer composite. In this research, the validity of applying the MoE to long, semi‐flexible fiber systems in which the majority of fibers are flexible is discussed. The components of the orientation tensor were first determined for a composite formed by a homogenous, simple shear field. The minimum acceptable image analysis width, or bin width, for the selected geometry was found to be ∼5.5 mm, or 1.4 times the average fiber length. This modified bin width was then used to determine the orientation at multiple percentages of flow within an injection‐molded, center‐gated disc, and compared to orientation values obtained utilizing the traditional, 0.7‐mm bin width. The results show that the traditional, 0.7‐mm bin width is sufficient for analysis of the center‐gated geometry. This fortuitous result is attributed to the axisymmetric nature of the center‐gated geometry, and the highly transverse fiber alignment seen within the samples, especially at moderate to high percentages of flow. In more complex flows, it is expected that the conventional bin width will not apply. POLYM. COMPOS., 2013. © 2013 Society of Plastics Engineers     

Reassessing the role of climate change in the Tupi expansion (South America, 5000–500 BP)

The expansion of forest farmers across tropical lowland South America during the Late Holocene has long been connected to climate change. The more humid conditions established during the Late Holocene are assumed to have driven the expansion of forests, which would have facilitated the dispersal of cultures that practised agroforestry. The Tupi, a language family of widespread distribution in South America, occupies a central place in the debate. Not only are they one of the largest families in the continent, but their expansion from an Amazonian homeland has long been hypothesized to have followed forested environments wherever they settled. Here, we assess that hypothesis using a simulation approach. We employ equation-based and cellular automaton models, simulating demic-diffusion processes under two different scenarios: a null model in which all land cells can be equally settled, and an alternative model in which non-forested cells cannot be settled or delay the expansion. We show that including land cover as a constraint to movement results in a better approximation of the Tupi expansion as reconstructed by archaeology and linguistics.     

Triacylglycerols and regiospecific fatty acid analyses of philippine seed oils

Three Philippine seed oils, namely coconut (Cocos nucifera Linn.), pilinut (Canarium ovatum Engl.), and cashew (Anacardium occidentale Linn.), which were selected for their local abundance and availability, were examined for their triacylglycerol profiles and fatty acid compositions. Triacylglycerol molecular species in terms of carbon number and partition number were determined by gas chromatography and liquid chromatography, respectively. The distribution of fatty acids in the primary and secondary positions of the glycerol backbones for the three oils were examined by regiospecific analysis by using pancreatic lipase. Coconut oil had high concentrations of lauric and myristic acids, while the other two oils did not have such fatty acids. Lauric acid in coconut oil and linoleic acid in pilinut oil were distributed mainly in the primary positions (sn-1,3) of the glycerol backbone. Trilaurin and dioleylpalmitoylglycerol were the major triglycerides in coconut and pilinut oils, respectively.     

Administration of recombinant human IL-7 to mice alters the composition of B-lineage cells and T cell subsets, enhances T cell function, and induces regression of established metastases

These studies investigate the effects of exogenously administered recombinant human IL-7 (rhIL-7) on mouse leukocyte subsets in vivo in normal and tumor-bearing mice. The administration of rhIL-7 to normal mice caused a pronounced leukocytosis (three- to fivefold increase over background) in the spleen and lymph nodes, with B-lineage and T cells, NK cells, and macrophages all being increased. CD8+ T cells increased disproportionately, such that the CD4 to CD8 ratio decreased dramatically. The rhIL-7-induced effects were dose-dependent, increased with duration of treatment, and were reversible after cessation of rhIL-7 administration. T cell number increases after rhIL-7 treatment were primarily a result of an expansion of the peripheral T cell population. Importantly, splenocytes from rhIL-7-treated mice have enhanced proliferative responses to various T cell stimuli in vitro and were able to potentiate an allogeneic CTL response in vivo. The rhIL-7-induced changes in T cell number and the CD4 to CD8 ratio also were observed in mice bearing early Renca renal adenocarcinoma pulmonary metastases, and these changes coincided with up to a 75% reduction in pulmonary metastases. Overall, these results demonstrate that the administration of rhIL-7 to mice profoundly increases the number of B and T cells, and reduces the number of pulmonary metastases. The results also suggest that IL-7 may be useful for restoring lymphoid subsets in immunosuppressed hosts and in enhancing T cell-mediated immune responses. Such effects may be useful in the treatment of microbial diseases and cancer.     

Simple lattice model with inertia for sand piles

In this article we make a critical analysis of the model proposed by Weber, present an improvement that gives the logarithmic correction on the shape of sandpiles properly, and study the normal forces on the surface supporting a pile using the improved model.