Using synchrotron-based X-Ray microtomography and functional contrast agents in environmental applications

Despite very rapid development in commercial X-ray tomography technology, synchrotron-based tomography facilities still have a number of advantages over conventional systems. The high photon flux inherent of synchrotron radiation sources allows for (i) high resolution to micro- or nanometer scales depending on the individual beamline, (ii) rapid acquisition times that allow for collection of sufficient data for statistically significant results in a short amount of time as well as prevention of temporal changes that would take place during longer scan times, and (iii) optimal implementation of contrast agents that allow us to resolve features that would not be decipherable in scans obtained with a polychromatic radiation source. This chapter highlights recent advances in capabilities at synchrotron sources, as well as implementation of synchrotron-based computed microtomography (CMT) to two topics of interest to researchers in the soil science, hydrology, and environmental engineering fields, namely multiphase flow in porous media and characterization of biofilm architecture in porous media. In both examples, we make use of contrast agents and photoelectric edge-specic scanning (single- or dual-energy type), in combination with advanced image processing techniques

Forchhammeria and Stixis (Brassicales): Stem and Wood Anatomical Diversity, Ecological and Phylogenetic Significance

Qualitative and quantitative data are given for wood anatomy of six of the 11 recognized species of Forchhammeria (Mexico, Central America, West Indies), a genus formerly placed in Capparaceae. Though still in Brassicales, the genus has been excluded, along with several other genera, from the major recognized families of that order on the basis of molecular data. Liquid-preserved material of several species permitted detailed histological accounts of the successive cambia and their development in the stems of Forchhammeria. Successive cambia have a curious distribution in Brassicales that may represent homoplasies. Most wood features of the genus do not appear highly xeromorphic, but presence of tracheids as a wood background tissue and abundance of starch and perhaps water storage in ray parenchyma and conjunctive tissue can be cited as mechanisms likely to resist embolism formation. Forchhammeria retains green leaves throughout the dry season. Forchhammeria tamaulipana, known only from Tamaulipas State, Mexico, the single species of a new subgenus, Pauciflora, is newly described. Its embryos have nearly equal cotyledons and germinate epigeously, whereas all remaining species of the genus are pseudomonocotylous and hypogeous. These and other distinctive features of F. tamaulipana may prove significant in providing links to other brassicalean genera. The family name Stixaceae Doweld is now appropriate for Forchhammeria, Neothorelia, Stixis, and Tirani

CASTILLEJA ALBOBARBATA SP. NOV. (OROBANCHACEAE) FROM SIERRAS MANANTL\uc1N AND CACOMA, JALISCO, MEXICO

Volume: 20Start Page: 1343End Page: 135

A Drosophila Model To Identify Polyamine-Drug Conjugates That Target The Polyamine Transporter In An Intact Epithelium

Polyamine transport is elevated in many tumor types, suggesting that toxic polyamine - drug conjugates could be targeted to cancer cells via the polyamine transporter (PAT). We have previously reported the use of Chinese hamster ovary (CHO) cells and its PAT-deficient mutant cell line, CHO-MG, to screen anthracene - polyamine conjugates for their PAT-selective targeting ability. We report here a novel Drosophilabased model for screening anthracene-polyamine conjugates in a developing and intact epithelium (Drosophila imaginal discs), wherein cell-cell adhesion properties are maintained. Data from the Drosophila assay are consistent with previous results in CHO cells, indicating that the Drosophila epithelium has a PAT with vertebrate-like characteristics. This assay will be of use to medicinal chemists interested in screening drugs that use PAT for cellular entry, and it offers the possibility of genetic dissection of the polyamine transport process, including identification of a Drosophila PAT. © 2008 American Chemical Society

Foundational Ethics of the Health Care System: The Moral and Practical Superiority of Free Market Reforms

Abstract Leprosy (Hansen's disease) has been associated with a deep stigma that dates back to ancient history

Upregulation of eNOS and unchanged energy metabolism in increased susceptibility of the aging type 2 diabetic GK rat heart to ischemic injury

We investigated the tolerance of the insulin-resistant diabetic heart to ischemic injury in the male Goto-Kakizaki (GK) rat, a model of type 2 diabetes. Changes in energy metabolism, nitric oxide (NO) pathway, and cardiac function were assessed in the presence of physiological substrates. Age-matched control Wistar (n = 19) and GK (n = 18) isolated rat hearts were perfused with 0.4 mM palmitate, 3% albumin, 11 mM glucose, 3 U/l insulin, 0.2 mM pyruvate, and 0.8 mM lactate for 24 min before switching to 1.2 mM palmitate (11 rats/group) during 32 min low-flow (0.5 ml·min−1·g wet wt−1) ischemia. Next, flow was restored with 0.4 mM palmitate buffer for 32 min. A subset of hearts from each group (n = 8 for control and n = 7 for GK groups) were freeze-clamped for determining baseline values after the initial perfusion of 24 min. ATP, phosphocreatine (PCr), and intracellular pH (pHi) were followed using 31P magnetic resonance spectroscopy with simultaneous measurement of contractile function. The NO pathway was determined by nitric oxide synthase (NOS) isoform expression and total nitrate concentration (NOx) in hearts. We found that coronary flow was 26% lower (P < 0.05) during baseline conditions and 61% lower (P < 0.05) during reperfusion in GK vs. control rat hearts. Rate pressure product was lower during reperfusion in GK vs. control rat hearts (P < 0.05). ATP, PCr, and pHi during ischemia-reperfusion were similar in both groups. Endothelial NOS expression was increased in GK rat hearts during baseline conditions (P < 0.05). NOx was increased during baseline conditions (P < 0.05) and after reperfusion (P < 0.05) in GK rat hearts. We report increased susceptibility of type 2 diabetic GK rat heart to ischemic injury that is not associated with impaired energy metabolism. Reduced coronary flow, upregulation of eNOS expression, and increased total NOx levels confirm NO pathway modifications in this model, presumably related to increased oxidative stress. Modifications in the NO pathway may play a major role in ischemia-reperfusion injury of the type 2 diabetic GK rat heart