544 research outputs found

    On the Milnor formula in arbitrary characteristic

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    The Milnor formula μ=2δ−r+1\mu=2\delta-r+1 relates the Milnor number μ\mu, the double point number δ\delta and the number rr of branches of a plane curve singularity. It holds over the fields of characteristic zero. Melle and Wall based on a result by Deligne proved the inequality μ≥2δ−r+1\mu\geq 2\delta-r+1 in arbitrary characteristic and showed that the equality μ=2δ−r+1\mu=2\delta-r+1 characterizes the singularities with no wild vanishing cycles. In this note we give an account of results on the Milnor formula in characteristic pp. It holds if the plane singularity is Newton non-degenerate (Boubakri et al. Rev. Mat. Complut. (2010) 25) or if pp is greater than the intersection number of the singularity with its generic polar (Nguyen H.D., Annales de l'Institut Fourier, Tome 66 (5) (2016)). Then we improve our result on the Milnor number of irreducible singularities (Bull. London Math. Soc. 48 (2016)). Our considerations are based on the properties of polars of plane singularities in characteristic pp.Comment: 18 page

    Diversity of culturable nocardioform actinomycetes from wastewater treatment plants in Spain and their role in the biodegradability of aromatic compounds

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    [EN] Currently, municipal and industrial wastewater treatment plants (WWTPs) are mainly focusing on reduction of biological oxygen demand and on the removal of nutrients. However, there are microorganisms that interfere with the process. In this environment, there is a large diversity of microorganisms that have not been studied in detail and that could provide real and practical solutions to the foaming problems. Among such microorganisms, Gram-positive actinomycete bacteria are of special interest because they are known for producing secondary metabolites as well as chemically diverse compounds and for their capacity to degrade recalcitrant pollutants. Three different media were chosen to isolate actinomycetes from 28 WWTPs in Spain. A total of 189 activated sludge samples were collected; 126 strains were isolated and identified to belong to 1 suborder, i.e. Corynebacterineae, and 7 genera, i.e. Corynebacterium, Dietzia, Gordonia, Mycobacterium, Rhodococcus, Tsukamurella and Williamsia. Furthermore, 71 strains were capable of biodegrading at least 1 aromatic product, and that 27 of them amplified for catA gene. The results of this research help us understand the complexity of the foam-forming microbial populations in Spain and it shows that WWTPs can be a good source of microorganisms that can degrade phenol or naphthalene.This work was supported by grants from Entidad Publica de Saneamiento de Aguas Residuales (EPSAR) de la Comunitat Valenciana.Soler HernĂĄndez, A.; GarcĂ­a HernĂĄndez, J.; Zornoza-Zornoza, AM.; Alonso Molina, JL. (2017). Diversity of culturable nocardioform actinomycetes from wastewater treatment plants in Spain and their role in the biodegradability of aromatic compounds. Environmental Technology. 39(2):172-181. https://doi.org/10.1080/09593330.2017.1296897S17218139

    Right Paraduodenal Hernia in an Adult Patient: Diagnostic Approach and Surgical Management

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    Paraduodenal hernia, a rare congenital anomaly which arises from an error of rotation of the midgut, is the most common type of intraabdominal hernia. There are two variants, right and left paraduodenal hernia, the right being less common. We report the case of a 41-year-old patient with a right paraduodenal hernia with a 6-month history of intermittent episodes of intestinal obstruction. Diagnosis was established by CT scan and upper gastrointestinal series with small bowel follow-through. In a planned laparotomy, herniation of the small bowel loops through the fossa of Waldeyer was found. Division of the lateral right attachments of the colon opened the hernia sac widely, replacing the pre- and postarterial segments of the intestine in the positions they would normally occupy at the end of the first stage of rotation during embryonic development. Six months after the surgery, after an uneventful recovery, the patient remains free of symptoms

    Purification and biochemical characterization of four iron superoxide dismutases in Trypanosoma cruzi

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    Four superoxide dismutase (SOD) activities (SOD I, II, III, and IV) have been characterized in the epimastigote form of Trypanosoma cruzi . The total extract was subjected to two successive ammonium sulphate additions between 35 and 85%, and the resulting fraction was purified using two continuous chromatography processes (ion exchange and filtration). Enzymes were insensitive to cyanide but sensitive to hydrogen peroxide, properties characteristic of iron-containing SODs. The molecular masses of the different SODs were 20 kDa (SOD I), 60 kDa (SOD II), 50 kDa (SOD III) and 25 kDa (SOD IV), whereas the isoelectric points were 6.9, 6.8, 5.2 and 3.8, respectively. Subcellular location and digitonin experiments have shown that these SODs are mainly cytosolic, with small amounts in the low- mass organelles (SOD II and SOD I) and the mitochondrion (SOD III), where these enzymes play an important role in minimizing oxidative damage.Financial support: CGL2006-27889-E/BOS, Ministerio de Ciencia y TecnologĂ­a

    A study of Docetaxel-induced effects in MCF-7 cells by means of Raman microspectroscopy

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    Chemotherapies feature a low success rate of about 25%, and therefore, the choice of the most effective cytostatic drug for the individual patient and monitoring the efficiency of an ongoing chemotherapy are important steps towards personalized therapy. Thereby, an objective method able to differentiate between treated and untreated cancer cells would be essential. In this study, we provide molecular insights into Docetaxel-induced effects in MCF-7 cells, as a model system for adenocarcinoma, by means of Raman microspectroscopy combined with powerful chemometric methods. The analysis of the Raman data is divided into two steps. In the first part, the morphology of cell organelles, e.g. the cell nucleus has been visualized by analysing the Raman spectra with k-means cluster analysis and artificial neural networks and compared to the histopathologic gold standard method hematoxylin and eosin staining. This comparison showed that Raman microscopy is capable of displaying the cell morphology; however, this is in contrast to hematoxylin and eosin staining label free and can therefore be applied potentially in vivo. Because Docetaxel is a drug acting within the cell nucleus, Raman spectra originating from the cell nucleus region were further investigated in a next step. Thereby we were able to differentiate treated from untreated MCF-7 cells and to quantify the cell–drug response by utilizing linear discriminant analysis models

    Molecular, microbiological and clinical characterization of Clostridium difficile isolates from tertiary care hospitals in Colombia

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    In Colombia, the epidemiology and circulating genotypes of Clostridium difficile have not yet been described. Therefore, we molecularly characterized clinical isolates of C.difficile from patients with suspicion of C.difficile infection (CDI) in three tertiary care hospitals. C.difficile was isolated from stool samples by culture, the presence of A/B toxins were detected by enzyme immunoassay, cytotoxicity was tested by cell culture and the antimicrobial susceptibility determined. After DNA extraction, tcdA, tcdB and binary toxin (CDTa/CDTb) genes were detected by PCR, and PCR-ribotyping performed. From a total of 913 stool samples collected during 2013–2014, 775 were included in the study. The frequency of A/B toxins-positive samples was 9.7% (75/775). A total of 143 isolates of C.difficile were recovered from culture, 110 (76.9%) produced cytotoxic effect in cell culture, 100 (69.9%) were tcdA+/tcdB+, 11 (7.7%) tcdA-/tcdB+, 32 (22.4%) tcdA-/tcdB- and 25 (17.5%) CDTa+/CDTb+. From 37 ribotypes identified, ribotypes 591 (20%), 106 (9%) and 002 (7.9%) were the most prevalent; only one isolate corresponded to ribotype 027, four to ribotype 078 and four were new ribotypes (794,795, 804,805). All isolates were susceptible to vancomycin and metronidazole, while 85% and 7.7% were resistant to clindamycin and moxifloxacin, respectively. By multivariate analysis, significant risk factors associated to CDI were, staying in orthopedic service, exposure to third-generation cephalosporins and staying in an ICU before CDI symptoms; moreover, steroids showed to be a protector factor. These results revealed new C. difficile ribotypes and a high diversity profile circulating in Colombia different from those reported in America and European countries

    Statin Therapy in Metabolic Syndrome and Hypertension Post-JUPITER: What is the Value of CRP?

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    Much evidence supports a pivotal role for inflammation in atherosclerosis. C-reactive protein (CRP), the prototypic marker of inflammation in humans, is a cardiovascular risk marker and may also promote atherogenesis. CRP levels are increased in metabolic syndrome and hypertension and confer increased risk of cardiovascular events in patients in these subgroups. Statins have been shown to lower low-density lipoproteins and CRP independently, and reduce cardiovascular events in subjects with and without metabolic syndrome and hypertension. In this review, we focus on the results from the primary prevention statin trial, Justification for the Use of statins in Primary prevention: an Intervention Trial Evaluating Rosuvastatin (JUPITER), which showed reductions in LDL, CRP, and cardiovascular events. Post-JUPITER, the new guidelines will now need to consider recommending high-sensitivity CRP testing to intermediate-risk metabolic syndrome patients and those with hypertension and intermediate risk so that we can better identify candidates at greater risk and reduce cardiovascular burden in these subjects with statin therapy

    Cerebrospinal Fluid Space Alterations in Melancholic Depression

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    Melancholic depression is a biologically homogeneous clinical entity in which structural brain alterations have been described. Interestingly, reports of structural alterations in melancholia include volume increases in Cerebro-Spinal Fluid (CSF) spaces. However, there are no previous reports of CSF volume alterations using automated whole-brain voxel-wise approaches, as tissue classification algorithms have been traditionally regarded as less reliable for CSF segmentation. Here we aimed to assess CSF volumetric alterations in melancholic depression and their clinical correlates by means of a novel segmentation algorithm (‘new segment’, as implemented in the software Statistical Parametric Mapping-SPM8), incorporating specific features that may improve CSF segmentation. A three-dimensional Magnetic Resonance Image (MRI) was obtained from seventy patients with melancholic depression and forty healthy control subjects. Although imaging data were pre-processed with the ‘new segment’ algorithm, in order to obtain a comparison with previous segmentation approaches, tissue segmentation was also performed with the ‘unified segmentation’ approach. Melancholic patients showed a CSF volume increase in the region of the left Sylvian fissure, and a CSF volume decrease in the subarachnoid spaces surrounding medial and lateral parietal cortices. Furthermore, CSF increases in the left Sylvian fissure were negatively correlated with the reduction percentage of depressive symptoms at discharge. None of these results were replicated with the ‘unified segmentation’ approach. By contrast, between-group differences in the left Sylvian fissure were replicated with a non-automated quantification of the CSF content of this region. Left Sylvian fissure alterations reported here are in agreement with previous findings from non-automated CSF assessments, and also with other reports of gray and white matter insular alterations in depressive samples using automated approaches. The reliable characterization of CSF alterations may help in the comprehensive characterization of brain structural abnormalities in psychiatric samples and in the development of etiopathogenic hypotheses relating to the disorders

    Role of transcriptional regulation in the evolution of plant phenotype: A dynamic systems approach

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    © 2015 Wiley Periodicals, Inc. A growing body of evidence suggests that alterations in transcriptional regulation of genes involved in modulating development are an important part of phenotypic evolution, and this can be documented among species and within populations. While the effects of differential transcriptional regulation in organismal development have been preferentially studied in animal systems, this phenomenon has also been addressed in plants. In this review, we summarize evidence for cis-regulatory mutations, trans-regulatory changes and epigenetic modifications as molecular events underlying important phenotypic alterations, and thus shaping the evolution of plant development. We postulate that a mechanistic understanding of why such molecular alterations have a key role in development, morphology and evolution will have to rely on dynamic models of complex regulatory networks that consider the concerted action of genetic and nongenetic components, and that also incorporate the restrictions underlying the genotype to phenotype mapping process.CONACyT 180098, 180380, 167705, 152649 and PAPIIT UNAM IN203214-3, IN203113-3, IN203814-3. BFU2012–34821 (MINECO) to C.G. and an institutional grant from Fundación Ramón Aceres to CBMSOPeer Reviewe
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