Natural and Artificial Functionalized Biopolyesters I. Chemoenzymatic Mediated Synthesis of Chiral Precursors

Design of optically active polymeric materials for temporary therapeutic and environmental applications requires the working-out of functionalized polymers with structures and properties adjusted to the considered applications. Biocompatibility of selected polymers is a required property in regard to the interactions between living organisms and macromolecular systems. It is therefore important to prepare highly optically active monomers and their corresponding hydrolyzable and biocompatible polymers. Bacterium Clostridium tetanomorphum is an useful source of enzymes for bioconversion and particularly in the chemoenzyrnatic route to optically active alkylmalolactonic acid esters and their optically pure stereoisomers. 3-Methylaspartase, involved in the glutamate fermentation pathway, is a very interesting enzyme, which can provide chiral precursors with high optically purity. This chemoenzymatic strategy can be used to prepare the four stereoisomers of 3-methylmalolaconic acid esters, by enzymatic resolution of natural and artificial stereoisomers of 3-methylaspartic acid. A series of 3-alkymalolactonic acid esters with alkyl equal to ethyl or isopropyl, have been also synthesized and transformed into corresponding optically active polyesters.     

A LANDSCAPE‐BASED APPROACH TO ESTIMATE RIPARIAN HYDROLOGICAL AND NITRATE REMOVAL FUNCTIONS1

ABSTRACT: This study evaluates a conceptual model developed for riparian zones in Ontario, Canada, that links landscape hydrogeological characteristics to riparian ground water hydrology and nitrate removal efficiency. Data from a range of riparian sites in the United States and Europe suggest that the riparian zone types identified in the model are consistent with patterns of riparian hydrology and nitrate flux and removal in many humid temperate landscapes. These data also support the view that a riparian width of less than 20 m is often sufficient for effective nitrate removal unless riparian sediments are coarse grained or nitrate transport occurs mainly in surface‐fed ground water seeps. This study assesses the possibility of using topographic, soil, surficial geology, and vegetation maps to determine landscape attributes linked by the model to riparian zone hydrological functioning and nitrate removal efficiency. Although mappable data can help in determining broad classes of riparian zones, field visits are necessary to determine non‐mappable riparian attributes such as seeps, organic horizons, and permeable sediment depth in the riparian zone. This research suggests that the conceptual model could be used for landscape management purposes in most temperate landscapes with minor modifications and that the hydrological component of the model could be adapted for contaminants other than nitrate.     

Prenatal diagnosis of MPPH syndrome

We report the prenatal sonographic detection of a fetus with megalencephaly, polymicrogyria, postaxial polydactyly and hydrocephaly. Only 14 patients have been reported in the literature so far, all but one were diagnosed postnatally. The polymicrogyria in the frontoparietal lobe was confirmed by prenatal magnetic resonance imaging. Additionally, a hypoplastic thymus as seen in a 22q11 deletion was present. Although polymicrogyria along with pre-axial polydactyly has been described in 22q11 deletion, the diagnosis of Di George syndrome was ruled out. The etiology of megalencephaly, polymicrogyria, postaxial polydactyly and hydrocephaly has not been revealed yet. A dominant as well as recessive inheritance has been suggested. © 2013 John Wiley & Sons, Ltd.     

Implementation of a medical command and control team in Switzerland

In case of a major incident or disaster, the advance medical rescue command needs to manage several essential tasks simultaneously. These include the rapid deployment of ambulance, police, fire and evacuation services, and their coordinated activity, as well as triage and emergency medical care on site. The structure of such a medical rescue command is crucial for the successful outcome of medical evacuation at major incidents. However, little data has been published on the nature and structure of the command itself. This study presents a flexible approach to command structure, with two command heads: one emergency physician and one experienced paramedic. This approach is especially suitable for Switzerland, whose federal system allows for different structures in each canton. This article examines the development of these structures and their efficiency, adaptability and limitations with respect to major incident response in the French‐speaking part of the country.     

Plant growth rates and seed size: a re-evaluation

Small-seeded plant species are often reported to have high relative growth rate or RGR. However, because RGR declines as plants grow larger, small-seeded species could achieve higher RGR simply by virtue of their small size. In contrast, size-standardized growth rate or SGR factors out these size effects. Differences in SGR can thus only be due to differences in morphology, allocation, or physiology. We used nonlinear regression to calculate SGR for comparison with RGR for 10 groups of species spanning a wide range of life forms. We found that RGR was negatively correlated with seed mass in nearly all groups, but the relationship between SGR and seed mass was highly variable. We conclude that small-seeded species only sometimes possess additional adaptations for rapid growth over and above their general size advantage.