Catch-up growth follows an abnormal pattern in experimental renal insufficiency and growth hormone treatment normalizes it

The primary goal of this study was to determine if the ability to undergo catch-up growth following a transient injury is preserved in an experimental model of moderate chronic renal failure (CRF) and the effect of growth hormone (GH) administration on such phenomenon. Young rats were subtotally nephrectomized (days 0 and 4) (Nx). From days 11 to 13, food intake was restricted in subgroups of Nx and control (C) rats (NxR and CR). After refeeding, subgroups of NxR and CR rats received GH from days 14 to 20 (NxRGH and CRGH). Rats were killed on days 14 (C, CR, Nx, NxR), 17 and 21 (C, CR, CRGH, Nx, NxR, NxRGH), and 36 (C, CR, Nx, NxR). Longitudinal growth rate was measured by osseous front advance in the proximal tibiae. With refeeding, growth rate of CR, NxR, and NXrGH rats became significantly greater than that of C, indicating catch-up growth. This occurred later and with lower growth rate in NxR than in CR rats, whereas the characteristics of catch-up growth in CR and NxRGH animals were similar. Changes in growth rate were associated with modifications in the morphology and proliferative activity of growth cartilage. We conclude that catch-up growth occurs in renal insufficiency but follows a different pattern from that observed with normal renal function. GH treatment normalizes the pattern of catch-up growth in CRF. Changes in growth velocity are associated to modifications in the structure and dynamics of growth cartilage

Building Conservation Partnerships in Costa Rica

The non-profit organization Centro Cientifico Tropical (CCT) wishes to create collaborative, long-lasting partnerships with organizations that support their mission of protecting the biological corridors and wider environment of Costa Rica. Our goal was to develop a set of criteria and generate a method for selecting organizations that could be valuable partners. We interviewed members of CCT to gauge their wants and needs in a partnership. We researched different organizations that may be of interest to them and developed criteria for appropriate partners. We recommend that rating companies based on their reputation, accessibility, added value, work in conservation technology, and past work in conservation are the most effective ways to find suitable partners for our sponsor

Computational Approaches to Zeolite-Based Adsorption Processes

Computational methods to calculate the properties of zeolites in gas adsorption and separation have proven to be a valuable complement to experimental work. Molecular simulation provides a molecular understanding of the mechanisms involved in the adsorption, desorption, and transport. The accuracy and reliability of the predictions depend on the models used for adsorbates and adsorbents, the force fields that describe the interaction, and the computational methods to calculate the properties. The selection of force fields and methods depends on the properties of the systems and on characteristics such as the flexibility of the framework, the hydrophobicity/hydrophilicity of the zeolite, the chirality, the silicon atom substitutions, the nature and concentration of extra framework cations, the composition of the guest gases, the measured property, etc. In this chapter, a brief description of the state of the art of molecular simulation applied to porous materials is provided, as well as a discussion of current challenges in the field.</p