2,202 research outputs found
Anaphylaxis in Pregnancy: a Rare Cause of Neonatal Mortality
Anaphylaxis is a rare condition in pregnancy. Drugs are the aetiological agents most often implicated. Maternal anaphylaxis can lead to significant fetal morbidity and even mortality if uterine perfusion and maternal oxygenation are compromised. Significant risk of neonatal neurological damage or death can occur even when the maternal clinical outcome is favourable. The authors present the case of a newborn, born at gestational age of 29 weeks, who died at 11 days of life with hypoxic-ischaemic cerebral injuries as a consequence of maternal anaphylaxis following the administration of amoxicillin in the community setting.info:eu-repo/semantics/publishedVersio
Study of non-equilibrium effects and thermal properties of heavy ion collisions using a covariant approach
Non-equilibrium effects are studied using a full Lorentz-invariant formalism.
Our analysis shows that in reactions considered here, no global or local
equilibrium is reached. The heavier masses are found to be equilibrated more
than the lighter systems. The local temperature is extracted using hot Thomas
Fermi formalism generalized for the case of two interpenetrating pieces of
nuclear matter. The temperature is found to vary linearly with bombarding
energy and impact parameter whereas it is nearly independent of the mass of the
colliding nuclei. This indicates that the study of temperature with medium size
nuclei is also reliable. The maximum temperatures obtained in our approach are
in a nice agreement with earlier calculations of other approaches. A simple
parametrization of maximal temperature as a function of the bombarding energy
is also given.Comment: LaTex-file, 17 pages, 8 figures (available upon request), Journal of
Physics G20 (1994) 181
Electro-oxidation of cyanide on active and non-active anodes: Designing the electrocatalytic response of cobalt spinels
[EN] The feasibility of the electrochemical technologies for wastewater treatment greatly relies on the design of
efficient but inexpensive electrocatalysts. It is generally accepted that the so-called ¿non-active¿ anodes (like the
boron-doped diamond (BDD) or SnO2-based anodes), producing highly oxidizing hydroxyl radicals, are the most
promising candidates for pollutants abatement. In this work, the electrocatalytic performance of various cobalt
oxides, pure and doped with Cu or Au, for CN¿ oxidation has been studied and compared with that of conventional
graphite, BDD, SnO2-Sb and SnO2-Sb-Pt. The metal oxide electrodes were prepared by thermal decomposition
of the salt precursors onto Ti. For the M-doped Co3O4 electrodes, the nominal M/Co ratios were Cu/
Co=0.07¿1.00; and Au/Co=0.05¿0.20. The electrodes were characterized by different techniques (XRD, SEM,
EDX, XPS) and their electrocatalytic response was studied by cyclic voltammetry and galvanostatic electrolysis in
a H-type cell in aqueous 0.1M NaOH. The obtained results show that the nature of the dopant plays a key role on
the electrocatalytic behavior of cobalt spinels. Thus, while Cu catalyzes the CN¿ electro-oxidation, Au declines
it. This is explained by the fact that, unlike Au (which segregates as Au-rich particles), Cu is effectively incorporated
into the spinel structure by forming a solid solution (CuxCo3-xO4). In this solid solution, atomic scale
Cu(spinel)-CN¿ specific interactions occur to catalyze the reaction, whereas in segregated Au particles the oxidation
is hindered probably by a too-strong adsorption of cyanide and/or its inaccessibility to oxide active sites.
Electrolysis runs have revealed that ¿active¿ over-saturated Cu-doped spinels (Cu/Co=1.00) exhibit higher
current efficiencies than conventional graphite and ¿non-active¿ BDD and SnO2-based anodes. Hence, we hereby
demonstrate that an inexpensive ¿active¿ electrocatalyst can show even higher efficiency than the most powerful
BDD anode. These results highlight the significance of anode design in the application of the electrochemical
technique for wastewater treatment.Financial support from the Spanish Ministerio de Economia y Competitividad and FEDER funds (MAT2016-76595-R, IJCI-2014-20012) is gratefully acknowledgedBerenguer, R.; Quijada, C.; La Rosa-Toro, A.; Morallón, E. (2019). Electro-oxidation of cyanide on active and non-active anodes: Designing the electrocatalytic response of cobalt spinels. Separation and Purification Technology. 208:42-50. https://doi.org/10.1016/j.seppur.2018.05.024S425020
Electrocatalytic Oxidation of Cyanide on Copper-doped Cobalt Oxide Electrodes
[EN] Copper and copper oxides are well-known excellent catalysts in several chemical processes, but their low mechanical and electrochemical stability restrict their direct utilization as electrodes in electrolytic processes. In this work, the incorporation of copper into cobalt oxide (CuxCo3-xO4) is presented as an excellent approach to obtain highly active and robust copper-based electrocatalysts. Particularly, the electrocatalytic performance of Ti-supported CuxCo3-xO4 electrodes (with 0 <= x <= 1.5) has been studied for the oxidation' of cyanide in alkaline media. Cyclic voltammetry and electrolysis runs show an outstanding effect of Cu on the activity, efficiency and kinetics of spinel CuxCo3-xO4 electrodes for CN(-)electro-oxidation. Despite being active oxides with high activity towards water oxidation, copper saturated (x=1.0) and oversaturated (x=1.5) spinels exhibit unprecedented 100% current efficiencies for the electro-oxidation of CN- in aqueous electrolyte. In situ surface enhanced Raman spectroscopy (SERS) reveals the specific adsorption of CN- ions on surface Cu species to be involved in the electrocatalytic oxidation mechanism. This electrocatalytic activity has been attributed to surface Cu(II) in the spinel lattice. Furthermore, the CuxCo3-xO4 electrodes also display high electrochemical stability. Therefore, they are considered excellent candidates for the sustainable electrochemical elimination of highly toxic cyanides.Financial support from the Spanish Ministerio de Economia y Competitividad and FEDER funds (MAT2016-76595-R, IJCI-2014-20012) and from the Generalitat Valenciana (PROMETEO2013/038) is gratefully acknowledged.Berenguer, R.; La Rosa-Toro, A.; Quijada, C.; Morallon, E. (2017). Electrocatalytic Oxidation of Cyanide on Copper-doped Cobalt Oxide Electrodes. Applied Catalysis B Environmental. 207:286-296. https://doi.org/10.1016/j.apcatb.2017.01.078S28629620
Cambios a largo plazo en la riqueza de especies en una comunidad de aves nidificantes en un pequeño archipiélago mediterráneo
We analyzed the pattern of species richness changes in a bird–breeding bird community on a small western Mediterranean archipelago (Columbretes Islands) over a 40–year period (1964–2003). The aim of this study was to qualitatively account for the relative roles of local and regional factors in shaping the community. As expected, we found that regional factors (at the metapopulation spatial scale) increased diversity whereas local factors (i.e. ecological) probably prevented further increases in diversity. We found that the archipelago gained four new species (two seabirds and two falconids) during the study period, whereas no extinctions were recorded. The community seems partially or completely closed to some groups of species (e.g. small–sized birds such as passerines and storm–petrels), probably owing to predatory exclusion by Eleonora falcons (Falco eleonorae). As newly arrived species have breeding calendars that do not fully overlap with those of resident species, competition for space in a rather saturated area is prevented. Preservation of rare species which increase gamma (regional) diversity rather than alpha diversity with common species should be the main local conservation goal.Este trabajo analiza los patrones de cambio en la riqueza de especies en una comunidad de aves nidificantes de un pequeño archipiélago mediterráneo (las islas Columbretes, Castellón) durante un periodo de 40 años (1964–2003). El estudio pretende valorar cualitativamente la influencia relativa de los factores locales y regionales. Como se esperaba, se encontró que los factores regionales (a la escala espacial de la metapoblación) aumentaron la diversidad, mientras que los factores ecológicos locales evitaron mayores incrementos. El archipiélago ganó cuatro especies durante el periodo de estudio (dos aves marinas y dos falcónidos), mientras que no se produjo ninguna extinción. La comunidad parece parcial o totalmente cerrada a ciertos grupos de especies, tales como las aves de pequeña talla (p.ej. Paseriformes y paíños) probablemente debido a la depredación excluyente por parte de los halcones de Eleonor (Falco eleanorae). Dado que las especies que son colonizadoras recientes tienen calendarios de cría que no se solapan completamente con los de las especies residentes, se evita la competencia por el espacio de cría en un área bastante saturada. La principal meta conservacionista debe ser la protección de las especies raras, que incrementan la diversidad gamma (regional), más que la diversidad alpha de las especies comunes
Recurrent gastric lactobezoar in an infant
Lactobezoars are a type of bezoar composed of undigested milk and mucus. The aetiology is likely multifactorial, being classically described in association with pre-term, low-birth weight infants fed with hyperconcentrated formula. The authors present a case of lactobezoar recurrence in a pre-term infant with oesophageal atresia. To our knowledge, this is the first report of recurrence of lactobezoar.info:eu-repo/semantics/publishedVersio
Functional expression of a penicillin acylase from the extreme thermophile Thermus thermophilus HB27 in Escherichia coli
Background: Penicillin acylases (PACs) are enzymes of industrial relevance in the manufacture of beta-lactam antibiotics. Development of a PAC with a longer half-life under the reaction conditions used is essential for the improvement of the operational stability of the process. A gene encoding a homologue to Escherichia coli PAC was found in the genome of the thermophilic bacterium Thermus thermophilus (Tth) HB27. Because of the nature of this PAC and its complex maturation that is crucial to reach its functional heterodimeric final conformation, the overexpression of this enzyme in a heterologous mesophilic host was a challenge. Here we describe the purification and characterization of the PAC protein from Tth HB27 overexpressed in Escherichia coli. Results: Fusions to a superfolder green fluorescent protein and differential membrane solubilization assays indicated that the enzyme remains attached through its amino-terminal end to the outer side of the cytoplasmic membrane of Tth cells. In order to overexpress this PAC in E. coli cells, a variant of the protein devoid of its membrane anchoring segment was constructed. The effect of the co-expression of chaperones and calcium supplementation of the culture medium was investigated. The total production of PAC was enhanced by the presence of DnaK/J and GrpE and even more by trigger factor and GroEL/ES. In addition, 10 mM calcium markedly improved both PAC specific and volumetric activities. Recombinant PAC was affinity-purified and proper maturation of the protein was confirmed by SDS-PAGE and MALDI-TOF analysis of the subunits. The recombinant protein was tested for activity towards several penicillins, cephalosporins and homoserine lactones. Hydrophobic acyl-chain penicillins were preferred over the rest of the substrates. Penicillin K (octanoyl penicillin) was the best substrate, with the highest specificity constant value (16.12 mM-1.seg-1). The optimum pH was aprox. 4 and the optimum temperature was 75 [DEGREE SIGN]C. The half-life of the enzyme at this temperature was 9.2 h. Conclusions: This is the first report concerning the heterologous expression of a pac gene from a thermophilic microorganism in the mesophilic host E. coli. The recombinant protein was identified as a penicillin K-deacylating thermozymeL.T., A.H. and J.B. acknowledge funding from the Spanish Ministry of Science (grants CIT 010000-2009-29, RyC2006-02441) and an institutional grant from Fundación Ramón Areces to CBMS
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Geostatistical radar-raingauge combination with nonparametric correlograms: methodological considerations and application in Switzerland
Modelling spatial covariance is an essential part of all geostatistical methods. Traditionally, parametric semivariogram models are fit from available data. More recently, it has been suggested to use nonparametric correlograms obtained from spatially complete data fields. Here, both estimation techniques are compared. Nonparametric correlograms are shown to have a substantial negative bias. Nonetheless, when combined with the sample variance of the spatial field under consideration, they yield an estimate of the semivariogram that is unbiased for small lag distances. This justifies the use of this estimation technique in geostatistical applications.
Various formulations of geostatistical combination (Kriging) methods are used here for the construction of hourly precipitation grids for Switzerland based on data from a sparse realtime network of raingauges and from a spatially complete radar composite. Two variants of Ordinary Kriging (OK) are used to interpolate the sparse gauge observations. In both OK variants, the radar data are only used to determine the semivariogram model. One variant relies on a traditional parametric semivariogram estimate, whereas the other variant uses the nonparametric correlogram. The variants are tested for three cases and the impact of the semivariogram model on the Kriging prediction is illustrated. For the three test cases, the method using nonparametric correlograms performs equally well or better than the traditional method, and at the same time offers great practical advantages.
Furthermore, two variants of Kriging with external drift (KED) are tested, both of which use the radar data to estimate nonparametric correlograms, and as the external drift variable. The first KED variant has been used previously for geostatistical radar-raingauge merging in Catalonia (Spain). The second variant is newly proposed here and is an extension of the first. Both variants are evaluated for the three test cases as well as an extended evaluation period. It is found that both methods yield merged fields of better quality than the original radar field or fields obtained by OK of gauge data. The newly suggested KED formulation is shown to be beneficial, in particular in mountainous regions where the quality of the Swiss radar composite is comparatively low. An analysis of the Kriging variances shows that none of the methods tested here provides a satisfactory uncertainty estimate. A suitable variable transformation is expected to improve this
Instability of insular tree communities in an Amazonian mega-dam is driven by impaired recruitment and altered species composition
Mega-dams create highly fragmented archipelagos, affecting biodiversity and ecosystem functioning in remnant forest isolates. This study assessed the long-term impact of dam-induced fragmentation on insular tropical tree communities, with the aim of generating robust recommendations to mitigate some of the detrimental biodiversity impacts associated with future dam development. We inventoried adult and sapling trees across 89 permanent plots, located on 36 islands and in three mainland continuous forest sites in the Balbina Dam, Brazilian Amazon. We examined differences in recruitment, structure, and composition of sapling and adult tree communities, in relation to plot-, patch- and landscape-scale attributes including area, isolation, and fire severity. Islands harboured significantly lower sapling (mean ± 95% CI 48.6 ± 3.8) and adult (5 ± 0.2) tree densities per 0.01 ha, than nearby mainland continuous forest (saplings, 65.7 ± 7.5; adults, 5.6 ± 0.3). Insular sapling and adult tree communities were more dissimilar than in mainland sites, and species compositions showed a directional shift away from mainland forests, induced by fire severity, island area, and isolation. Insular sapling recruitment declined with increasing fire severity; tree communities with higher community-weighted mean wood density showed the greatest recruitment declines. Our results suggest that insular tree communities are unstable, with rare species becoming extinction-prone due to reduced tree recruitment and density on islands, potentially leading to future losses in biodiversity and ecosystem functioning across Balbina's >3,500 reservoir islands. Policy implications. In Balbina, fire and reduced habitat area and connectivity were drivers of tree community decay after only 28 years of insularization, despite strict protection provided by the ~940,000 ha Uatumã Biological Reserve. Given that many dams are planned for lowland, moderately undulating Amazonia, we recommend that dam development strategy explicitly considers (a) dam location, aiming to minimize creation of small (<10 ha) and isolated islands, (b) maintaining reservoir water levels during droughts to reduce fire risk, and (c) including aggregate island area in environmental impact and offset calculations. Ideally, we recommend that alternatives to hydropower be sought in lowland tropical regions, due to the far-reaching biodiversity losses and ecosystem disruption caused by river impoundment
Pilot Study: Systemic response after lung SBRT analyzing immune Cells phenotyping
To investigate changes of immune-phenotyping values in
patients treated with Stereotactic Body Radiation Therapy
(SBRT) over the lung in order to evaluate the immune
response after radiation therapy
- …