52 research outputs found
Metabolic synergies in the biotransformation of organic and metallic toxic compounds by a saprotrophic soil fungus
The saprotrophic fungus Penicillium griseofulvum was chosen as model organism to study responses to a mixture of hexachlorocyclohexane (HCH) isomers (α-HCH, ÎČ-HCH, Îł-HCH, ÎŽ-HCH) and of potentially toxic metals (vanadium, lead) in solid and liquid media. The P. griseofulvum FBL 500 strain was isolated from polluted soil containing high concentrations of HCH isomers and potentially toxic elements (Pb, V). Experiments were performed in order to analyse the tolerance/resistance of this fungus to xenobiotics, and to shed further light on fungal potential in inorganic and organic biotransformations. The aim was to examine the ecological and bioremedial potential of this fungus verifying the presence of mechanisms that allow it to transform HCH isomers and metals under different, extreme, test conditions. To our knowledge, this work is the first to provide evidence on the biotransformation of HCH mixtures, in combination with toxic metals, by a saprotrophic non-white-rot fungus and on the metabolic synergies involved
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Once bitten, not necessarily shy? Determinants of foreign market re-entry commitment strategies
We investigate foreign market re-entry commitment strategies, namely the changes in the modes of operation (commitment) undertaken by multinational enterprises (MNEs) as they return to foreign markets from which they had previously exited. We combine organisational learning theory with the institutional change literature to examine the antecedents of re-entry commitment strategies. From an analysis of 1,020 re-entry events between 1980 and 2016, we find that operation mode prior to exit is a strong predictor of subsequent re-entry mode. Contrary to the predictions of learning theory, we did not find support for the effect of experience accumulated during the initial market endeavour on the re-entry commitment strategies of MNEs. In turn, exit motives significantly impact on the re-entrants' decision to re-enter via a different mode of operation, by either increasing or decreasing their commitment to the market. We show that re-entrants do not replicate unsuccessful operation mode strategies if they had previously underperformed in the market. When favourable host institutional changes occur during the time-out period re-entrants tend to increase commitment in the host market irrespective of the degree of prior experience accumulated in the market
Formas de AlumĂnio em Solos Ăcidos Brasileiros com Teores Excepcionalmente Altos de Al3+ ExtraĂvel com KCI
Unraveling genetic predisposition to familial or early onset gastric cancer using germline whole-exome sequencing
Recognition of individuals with a genetic predisposition to gastric cancer (GC) enables preventive measures. However, the underlying cause of genetic susceptibility to gastric cancer remains largely unexplained. We performed germline whole-exome sequencing on leukocyte DNA of 54 patients from 53 families with genetically unexplained diffuse-type and intestinal-type GC to identify novel GC-predisposing candidate genes. As young age at diagnosis and familial clustering are hallmarks of genetic tumor susceptibility, we selected patients that were diagnosed below the age of 35, patients from families with two cases of GC at or below age 60 and patients from families with three GC cases at or below age 70. All included individuals were tested negative for germline CDH1 mutations before or during the study. Variants that were possibly deleterious according to in silico predictions were filtered using several independent approaches that were based on gene function and gene mutation burden in controls. Despite a rigorous search, no obvious candidate GC predisposition genes were identified. This negative result stresses the importance of future research studies in large, homogeneous cohorts
Planar antiresonant reflecting optical waveguides as integrated optical refractometer
This paper reports on an integrated refractometer sensor, useful for measuring chemical quantities, based on antiresonant reflecting optical waveguides (ARROWs). We show that, by a suitable design, the attenuation in ARROW waveguides can strongly depend on the refractive index of the superstrate layer. We use this property to design and realize an integrated refractometer. The proposed sensor structure is unique in that it consists in the ARROW waveguide itself acting like a vertical interferometer. The device is fabricated using standard silicon technology fully compatible with bipolar and CMOS integrated circuit process. The measurement results show a sensing resolution of n = 6e-4 when used in a solution with a refractive index of 1.4600
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