Self-immolative linkers in polymeric delivery systems

There has been significant interest in the methodologies of controlled release for a diverse range of applications spanning drug delivery, biological and chemical sensors, and diagnostics. The advancement in novel substrate-polymer coupling moieties has led to the discovery of self-immolative linkers. This new class of linker has gained popularity in recent years in polymeric release technology as a result of stable bond formation between protecting and leaving groups, which becomes labile upon activation, leading to the rapid disassembly of the parent polymer. This ability has prompted numerous studies into the design and development of self-immolative linkers and the kinetics surrounding their disassembly. This review details the main concepts that underpin self-immolative linker technologies that feature in polymeric or dendritic conjugate systems and outlines the chemistries of amplified self-immolative elimination

Soil quality assessment based on soil organic matter pools under long‐term tillage systems and following tillage conversion in a semi‐humid region

A field study was conducted to assess the long-term effects of no-tillage (NT) and conventional tillage (CT), and the short-term effects following tillage conversion -from CT to NT (NTn) and from NT to CT (CTn) on soil quality (SQ) indicators in a semi-humid climate. First, plots of a long-term tillage experiment on a Luvic Phaeozem initiated in 1986, were split into two subplots in 2012, yielding four treatments: NT, CT, NTn and CTn. In 2015, composite soil samples were collected from each treatment and from a natural site (Ref) at depths 0-5, 5-10, 10-20 and 0-20 cm. Several indicators were determined: soil organic carbon (SOC) and nitrogen (SON); particulate organic C (POM-C) and N (POM-N); potential N mineralization (PMN) and soil respiration (Rs). Moreover, bulk density was determined in long-term tillage systems. Different ratios between indicators were calculated, with emphasis on its function in the agroecosystem, i.e. functional indicators. Significant differences in SOC, SON and PMN were found between CT and NT at most depths. In contrast, three years after tillage conversion, only a part of the SQ indicators studied were modified mainly at the 0-10 cm depth. The functional indicators showed differences between tillage systems in the long-term and after short-term tillage conversion depending on the depth; however, the PMN/SON ratio demonstrated differences at all depths. Under these conditions, this ratio -related to easily mineralizable N fraction- proved to be a promising indicator for assessing SQ under contrasting tillage systems regardless of the sampling depth.Fil: Martinez, Juan Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; ArgentinaFil: Galantini, Juan Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; ArgentinaFil: Duval, Matias Ezequiel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina. Universidad Nacional del Sur. Departamento de Agronomía; ArgentinaFil: López, Fernando Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentin

First observation of excited states in 173Hg

The neutron-deficient nucleus 173Hg has been studied following fusion-evaporation reactions. The observation of gamma rays decaying from excited states are reported for the first time and a tentative level scheme is proposed. The proposed level scheme is discussed within the context of the systematics of neighbouring neutron-deficient Hg nuclei. In addition to the gamma-ray spectroscopy, the alpha decay of this nucleus has been measured yielding superior precision to earlier measurements.Comment: 5 pages, 4 figure

Evaluation of the potential index model to predict habitat suitability of forest species: the potential distribution of mountain pine (Pinus uncinata) in the Iberian peninsula

Characterization of the suitability or potentiality of a territory for forest tree species is an important source of information for forest planning and managing. In this study, we compared a relatively simple methodology to generate potential habitat distribution areas that has been traditionally used in Spain (the potential index model) with a statistical modelling approach (generalized linear model). We modelled the potential distribution of mountain pine (Pinus uncinata) in the Iberian peninsula as a working example. The potential index model generated a map of habitat suitability according to the values of an index of potentiality, whose distribution has usually divided into four categories based on quartiles (from optimum to low suitability). Considering all values of the index of potentiality as presences of mountain pine resulted in a low to moderate degree of agreement between the potential index model and the generalized linear model according to the kappa coefficient. Using the cut-off value of the index of potentiality that maximized the degree of agreement between both modelling approaches resulted in a substantial similarity between the maps of the predicted distribution of mountain pine. This cut-off value did lie in the upper-third quartile of the potential index distribution (high suitability category), and roughly coincided with the upper 30th percentile. The use of statistical techniques, which have proved to be powerful and versatile for species distribution modelling, is recommended. However, the potential index model, together with the adjustments proposed here, could be a reasonably simple methodology to predict the potential distribution of forest tree species that forest managers should take into account when evaluating forestation and afforestation projects

Development of a Keetch and Byram based drought index sensitive to forest management in Mediterranean conditions

[EN] The present work aims to take a closer look at the behavior of two releases of the Keetch Byram droughtindex (KBDI) under different forest management strategies in Mediterranean conditions. Since theseversions of the index were demonstrated to be insensitive to the changes in water balance caused bydifferent thinning treatments, a new KBDI-based index sensitive to silviculture operations was developed.This new approach enabled us to simulate the benefits achieved from a thinning operation in terms offorest fire risk reduction. Abatements of 22.5% and 26.4% in KBDI were obtained for the 2009 and 2010high-risk forest fire periods, respectively, due to thinning. The reductions observed in the short-term didnot disappear in a long term. A plot thinned 10 years ago showed KBDI reductions of 12.5% and 6.7% withrespect to a non-managed plot (control treatment) in the same period. Finally, in order to make possibleapplication of the new index to other stands, coefficients of the index were based on well-known andeasy to get tree-related and physiological variables.This study is part of the research project: "CGL2011-28776-C02-02, Hydrological characterization of forest structures at plot scale for an adaptive management, Hydrosil", funded by the Spanish Ministry of Science and Innovation and FEDER funds.García Prats, A.; Campo García, ADD.; Tarcisio Fernandes, JG.; Molina Herrera, A. (2015). Development of a Keetch and Byram based drought index sensitive to forest management in Mediterranean conditions. Agricultural and Forest Meteorology. (205):40-50. https://doi.org/10.1016/j.agrformet.2015.02.009S405020