125 research outputs found

    Ligand-Based Regulation of Dynamics and Reactivity of Hemoproteins

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    Hemoproteins include several heme-binding proteins with distinct structure and function. The presence of the heme group confers specific reactivity and spectroscopic properties to hemoproteins. In this review, we provide an overview of five families of hemoproteins in terms of dynamics and reactivity. First, we describe how ligands modulate cooperativity and reactivity in globins, such as myoglobin and hemoglobin. Second, we move on to another family of hemoproteins devoted to electron transport, such as cytochromes. Later, we consider heme-based reactivity in hemopexin, the main heme-scavenging protein. Then, we focus on heme-albumin, a chronosteric hemoprotein with peculiar spectroscopic and enzymatic properties. Eventually, we analyze the reactivity and dynamics of the most recently discovered family of hemoproteins, i.e., nitrobindins

    Análisis del Tipo y Valor de una Impedancia Limitadora de Corrientes de Cortocircuito Monofásicas a Tierra en el Nivel de 33 Kv para su Instalación en Estaciones Transformadoras 132 /33 /13,2 Kv

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    Se ha desarrollado un algoritmo en Matlab para realizar estudios de sensibilidad de corrientes de cortocircuito y sobretensiones en fases sanas según diferentes tipos y valores de impedancias de puesta a tierra para transformadores de tres arrollamientos. El algoritmo se aplica a Estaciones Transformadoras distribuidas en la provincia de Santa Fe que abastecen líneas débiles en el nivel de 33 [kV] pertenecientes a la Empresa Provincial de la Energía. De los análisis de sensibilidad realizados se infiere que las reactancias de puesta a tierra presentan un comportamiento más apropiado en comparación con los resistores, siendo los valores ideales 7 y 13 [Ω] para todas aquellas estaciones transformadoras con transformadores de 30 y 15 [MVA] respectivamente. Su inclusión representa una reducción aproximada del 60 % en la magnitud de las corrientes de falla a tierra y una atenuación del orden al 35% de los efectos electrodinámicos en el transformador

    Validation of the Mini Nutritional Assessment-Short Form in a population of frail elders without disability. Analysis of the Toulouse Frailty Platform population in 2013

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    **Objective** To assess the validity of the Mini Nutritional Assessment-Short Form (MNA-SF) in elderly patients from the Toulouse Frailty Platform. **Participants** Overall, 267 patients aged 65 and over, without severe cognitive impairment (i.e. Mini Mental Status Examination > 20 and CDR<1), no physical disability (i.e. Activities of Daily Living ≥ 5) and no active cancer history (over the past 12 months) were included in 2013. **Measurements** Receiver operating characteristic (ROC) analyses were used to assess the predictive validity of the French version of the MNA-SF for good nutritional status (defined as a full MNA score≥24/30). Analyses were conducted in the overall sample and then in subgroups of frail and pre-frail subjects according to the frailty phenotype. Optimal cut-off points were determined to obtain the best sensitivity/specificity ratio and the highest number of correctly classified subjects. **Results** Among 267 patients, mean age=81.5±5.8; women=67.0%; 138 (51.7%) were frail, 98 (36.7%) were pre-frail and 31 (11.6%) were robust. Given their MNA-SF scores, 201 (75.3%) had a good nutritional status, 61 (22.8%) were at risk of malnutrition and 5 (1.9%) were malnourished. In the overall sample, but also in subgroups of pre-frail or frail elders, the areas under ROC curves were 0.954, 0.948 and 0.958 respectively. The 11 points cut-off provided the best correct classification ratio (91.4%); sensitivity=94.0%, specificity=83.3%. **Conclusion** The MNA-SF appeared to be a validated and effective tool for malnutrition screening in frail elders. Implementing this tool in clinical routine should contribute to improving the screening of malnourished frail individuals

    Bryozoans are Major Modern Builders of South Atlantic Oddly Shaped Reefs

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    Supplementary information accompanies this paper at https://doi.org/10.1038/s41598-018-27961-6.In major modern reef regions, either in the Indo-Pacific or the Caribbean, scleractinian corals are described as the main reef framework builders, often associated with crustose coralline algae. We used underwater cores to investigate Late Holocene reef growth and characterise the main framework builders in the Abrolhos Shelf, the largest and richest modern tropical reef complex in the South Western Atlantic, a scientifically underexplored reef province. Rather than a typical coralgal reef, our results show a complex framework building system dominated by bryozoans. Bryozoans were major components in all cores and age intervals (2,000 yrs BP), accounting for up to 44% of the reef framework, while crustose coralline algae and coral accounted for less than 28 and 23%, respectively. Reef accretion rates varied from 2.7 to 0.9 mm yr−1, which are similar to typical coralgal reefs. Bryozoan functional groups encompassed 20 taxa and Celleporaria atlantica (Busk, 1884) dominated the framework at all cores. While the prevalent mesotrophic conditions may have driven suspensionfeeders’ dominance over photoautotrophs and mixotrophs, we propose that a combination of historical factors with the low storm-disturbance regime of the tropical South Atlantic also contributed to the region’s low diversity, and underlies the unique mushroom shape of the Abrolhos pinnacles.We thank CNPq/FAPES-Sisbiota/PELD, CAPES/IODP, CAPES/Ciências do Mar, and ANP/Brasoil for long term project funding. We also thank ICMBio for research permits and field logistic support, and Conservation International for providing and authorizing the use of the IKONOS image. JMW and JCB are International Visiting Researcher at UFES and JBRJ, supported by the Science Without Borders program. Zá Cajueiro provided invaluable field support and Ronaldo Francini, Carlos Janovitch and Lucio Engler helped in the drilling operations. This is a contribution from the Rede Abrolhos (abrolhos.org)

    Neurodevelopmental risk factors in schizophrenia

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    The authors review environmental and neurodevelopmental risk factors for schizophrenic disorders, with emphasis on minor physical anomalies, particularly craniofacial anomalies and dermatoglyphic variations. The high prevalence of these anomalies among schizophrenic subjects supports the neurodevelopmental theory of the etiology of schizophrenia, since they suggest either genetically or epigenetically controlled faulty embryonic development of structures of ectodermal origin like brain and skin. This may disturb neurodevelopment that in turn may cause these subjects to be at increased risk for the development of schizophrenia and related disorders. The precise confirmation of this theory, at least in some cases, will provide further understanding of these illnesses, allowing easy and inexpensive identification of subjects at risk and providing guidelines for the development of new pharmacological interventions for early treatment and even for primary prevention of the illness

    Nucleolin binds to a subset of selenoprotein mRNAs and regulates their expression

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    Selenium, an essential trace element, is incorporated into selenoproteins as selenocysteine (Sec), the 21st amino acid. In order to synthesize selenoproteins, a translational reprogramming event must occur since Sec is encoded by the UGA stop codon. In mammals, the recoding of UGA as Sec depends on the selenocysteine insertion sequence (SECIS) element, a stem-loop structure in the 3′ untranslated region of the transcript. The SECIS acts as a platform for RNA-binding proteins, which mediate or regulate the recoding mechanism. Using UV crosslinking, we identified a 110 kDa protein, which binds with high affinity to SECIS elements from a subset of selenoprotein mRNAs. The crosslinking activity was purified by RNA affinity chromatography and identified as nucleolin by mass spectrometry analysis. In vitro binding assays showed that purified nucleolin discriminates among SECIS elements in the absence of other factors. Based on siRNA experiments, nucleolin is required for the optimal expression of certain selenoproteins. There was a good correlation between the affinity of nucleolin for a SECIS and its effect on selenoprotein expression. As selenoprotein transcript levels and localization did not change in siRNA-treated cells, our results suggest that nucleolin selectively enhances the expression of a subset of selenoproteins at the translational level

    EEG Microstate Analysis in Drug-Naive Patients with Panic Disorder

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    Patients with panic disorder (PD) have a bias to respond to normal stimuli in a fearful way. This may be due to the preactivation of fear-associated networks prior to stimulus perception. Based on EEG, we investigated the difference between patients with PD and normal controls in resting state activity using features of transiently stable brain states (microstates). EEGs from 18 drug-naive patients and 18 healthy controls were analyzed. Microstate analysis showed that one class of microstates (with a right-anterior to left-posterior orientation of the mapped field) displayed longer durations and covered more of the total time in the patients than controls. Another microstate class (with a symmetric, anterior-posterior orientation) was observed less frequently in the patients compared to controls. The observation that selected microstate classes differ between patients with PD and controls suggests that specific brain functions are altered already during resting condition. The altered resting state may be the starting point of the observed dysfunctional processing of phobic stimuli

    Peri-implant diseases : a systematic review of the literature

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    Peri-implantitis surrounding oral implants is an inflammatory process affecting the soft and hard tissues resulting in rapid loss of supporting bone associated with bleeding and suppuration. The etiopathogenesis of early and late peri-implantitis is less well understood and seems to be related to the peri-implant environment and to the soft tissues/implant interface, to patient-related factors (smoke, systemic diseases, plaque control) and to host-parasite equilibrium. However, there is wide scientific evidence that demonstrates the direct correlation between oral microbiota and peri-implant mucositis or peri-implantitis. In particular, adherence and colonization of microbiota on plaque-exposed biomaterials, like c.p. titanium, are discriminant factors for the development of infection. Regenerative or resective surgical approaches are proposed for the treatment of peri-implantitis depending on the morphology and the shape of bone defects. The therapeutical approach of peri-implantitis surrounding dental implants comprises several aspects such as the removal of supra-gingival bacterial plaque, an appropriate surgical approach, the removal of granulation tissue and detoxification of the exposed implant surface, the elimination of the anaerobic ecosystem by the removal of peri-implant pocket (gingivectomy or apically repositioned flap) or by the regeneration of the peri-implant hard tissues and, finally, the establishment of an efficient plaque control regimen
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