1,980 research outputs found

    Axial heterogeneity of vasopressin-receptor subtypes along the human and mouse collecting duct.

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    Vasopressin and vasopressin antagonists are finding expanded use in mouse models of disease and in clinical medicine. To provide further insight into the physiological role of V1a and V2 vasopressin receptors in the human and mouse kidney, intrarenal localization of the receptors mRNA was determined by in situ hybridization. V2-receptor mRNA was predominantly expressed in the medulla, whereas mRNA for V1a receptors predominated in the cortex. The segmental localization of vasopressin-receptor mRNAs was determined using simultaneous in situ hybridization and immunohistochemistry for segment-specific markers, including aquaporin-2, Dolichos biflorus agglutinin, epithelial Na channels, Tamm Horsfall glycoprotein, and thiazide-sensitive Na(+)-Cl(-) cotransporter. Notably, V1a receptor expression was exclusively expressed in V-ATPase/anion exchanger-1-labeled alpha-intercalated cells of the medullary collecting duct in both mouse and human kidney. In cortical collecting ducts, V1a mRNA was more widespread and detected in both principal and intercalated cells. V2-receptor mRNA is diffusely expressed along the collecting ducts in both mouse and human kidney, with higher expression levels in the medulla. These results demonstrate heterogenous axial expression of both V1a and V2 vasopressin receptors along the human and mouse collecting duct. The restricted expression of V1a-receptor mRNA in intercalated cells suggests a role for this receptor in acid-base balance. These findings further suggest distinct regulation of renal transport function by AVP through V1a and V2 receptors in the cortex vs. the medulla

    Structural parameterizations for boxicity

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    The boxicity of a graph GG is the least integer dd such that GG has an intersection model of axis-aligned dd-dimensional boxes. Boxicity, the problem of deciding whether a given graph GG has boxicity at most dd, is NP-complete for every fixed d2d \ge 2. We show that boxicity is fixed-parameter tractable when parameterized by the cluster vertex deletion number of the input graph. This generalizes the result of Adiga et al., that boxicity is fixed-parameter tractable in the vertex cover number. Moreover, we show that boxicity admits an additive 11-approximation when parameterized by the pathwidth of the input graph. Finally, we provide evidence in favor of a conjecture of Adiga et al. that boxicity remains NP-complete when parameterized by the treewidth.Comment: 19 page

    Effects of tidal-forcing variations on tidal properties along a narrow convergent estuary

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    A 1D analytical framework is implemented in a narrow convergent estuary that is 78 km in length (the Guadiana, Southern Iberia) to evaluate the tidal dynamics along the channel, including the effects of neap-spring amplitude variations at the mouth. The close match between the observations (damping from the mouth to ∼ 30 km, shoaling upstream) and outputs from semi-closed channel solutions indicates that the M2 tide is reflected at the estuary head. The model is used to determine the contribution of reflection to the dynamics of the propagating wave. This contribution is mainly confined to the upper one third of the estuary. The relatively constant mean wave height along the channel (< 10% variations) partly results from reflection effects that also modify significantly the wave celerity and the phase difference between tidal velocity and elevation (contradicting the definition of an “ideal” estuary). Furthermore, from the mouth to ∼ 50 km, the variable friction experienced by the incident wave at neap and spring tides produces wave shoaling and damping, respectively. As a result, the wave celerity is largest at neap tide along this lower reach, although the mean water level is highest in spring. Overall, the presented analytical framework is useful for describing the main tidal properties along estuaries considering various forcings (amplitude, period) at the estuary mouth and the proposed method could be applicable to other estuaries with small tidal amplitude to depth ratio and negligible river discharge.info:eu-repo/semantics/publishedVersio

    Transcriptional and Functional Studies of a Cd(II)/Pb(II)-Responsive Transcriptional Regulator(CmtR) from Acidithiobacillus ferrooxidans ATCC 23270

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    The acidophilic Acidithiobacillusferrooxidans can resist exceptionally high cadmium (Cd) concentrations. This property is important for its use in biomining processes, where Cd and other metal levels range usually between 15 and 100 mM. To learn about the mechanisms that allow A. ferrooxidans cells to survive in this environment, a bioinformatic search of its genome showed the presence of that a Cd(II)/Pb(II)-responsive transcriptional regulator (CmtR) was possibly related to Cd homeostasis. The expression of the CmtR was studied by real-time reverse transcriptase PCR using A. ferrooxidans cells adapted for growth in the presence of high concentrations of Cd. The putative A. ferrooxidans Cd resistance determinant was found to be upregulated when this bacterium was exposed to Cd in the range of 15–30 mM. The CmtR from A. ferrooxidans was cloned and expressed in Escherichiacoli, the soluble protein was purified by one-step affinity chromatography to apparent homogeneity. UV–Vis spectroscopic measurements showed that the reconstruction CmtR was able to bind Cd(II) forming Cd(II)–CmtR complex in vitro. The sequence alignment and molecular modeling showed that the crucial residues for CmtR binding were likely to be Cys77, Cys112, and Cys121. The results reported here strongly suggest that the high resistance of the extremophilic A. ferrooxidans to Cd including the Cd(II)/Pb(II)-responsive transcriptional regulator

    Hydrogen bond induced change of geometry and crystallized form of copper(II) complexes: syntheses and crystal structure of complexes with Schiff-base ligands containing two imidazolyl groups

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    Copper(II) complexes with the Schiff base methylbis[3-(5-methylimidazol-4-ylmethyleneimino)propyl]amine (BDPA), [Cu(BDPA)][ClO4](2).H2O 1 and [Cu(BDPA)][PF6](2) 2, and with a deprotonated Schiff base ligand [H2BIPO=1,3-bis[(5-methylimidazol-4-ylmethyleneimino)propan-2-ol], {[Cu(HBIPO)]ClO4.H2O}(n) 3 and 4, have been prepared. Single-crystal structures show that 1 adopts a distorted square-pyramidal geometry with the basal plane occupied by an imidazole nitrogen, two imines and one amino nitrogen atom and the apical position by another nitrogen atom from BDPA. 2 adopts a distorted trigonal-bipyramidal geometry with two imidazole nitrogen atoms at axial positions. Both 3 and 4 adopt distorted square-pyramidal geometry with four nitrogen atoms from HBIPO in the basal plane and the apical position occupied by a deprotonated imidazole nitrogen atom from an adjacent [Cu(HBIPO)] unit, resulting in polynuclear complexes. The differences in geometry and crystallization pathway between 1 and 2, and 3 and 4, are discussed based on the crystal structures, indicating that hydrogen bonding to the basal plane imidazole group plays an important role both in the change of geometry and crystallization form of the copper(II) complexes

    Malignancy risk analysis in patients with inadequate fine needle aspiration cytology (FNAC) of the thyroid

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    Background Thyroid fine needle aspiration cytology (FNAC) is the standard diagnostic modality for thyroid nodules. However, it has limitations among which is the incidence of non-diagnostic results (Thy1). Management of cases with repeatedly non-diagnostic FNAC ranges from simple observation to surgical intervention. We aim to evaluate the incidence of malignancy in non-diagnostic FNAC, and the success rate of repeated FNAC. We also aim to evaluate risk factors for malignancy in patients with non-diagnostic FNAC. Materials and Methods Retrospective analyses of consecutive cases with thyroid non diagnostic FNAC results were included. Results Out of total 1657 thyroid FNAC done during the study period, there were 264 (15.9%) non-diagnostic FNAC on the first attempt. On repeating those, the rate of a non-diagnostic result on second FNAC was 61.8% and on third FNAC was 47.2%. The overall malignancy rate in Thy1 FNAC was 4.5% (42% papillary, 42% follicular and 8% anaplastic), and the yield of malignancy decreased considerably with successive non-diagnostic FNAC. Ultrasound guidance by an experienced head neck radiologist produced the lowest non-diagnostic rate (38%) on repetition compared to US guidance by a generalist radiologist (65%) and by non US guidance (90%). Conclusions There is a low risk of malignancy in patients with a non-diagnostic FNAC result, commensurate to the risk of any nodule. The yield of malignancy decreased considerably with successive non-diagnostic FNAC

    Ucma/GRP inhibits phosphate-induced vascular smooth muscle cell calcification via SMAD-dependent BMP signalling

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    Vascular calcification (VC) is the process of deposition of calcium phosphate crystals in the blood vessel wall, with a central role for vascular smooth muscle cells (VSMCs). VC is highly prevalent in chronic kidney disease (CKD) patients and thought, in part, to be induced by phosphate imbalance. The molecular mechanisms that regulate VC are not fully known. Here we propose a novel role for the mineralisation regulator Ucma/GRP (Upper zone of growth plate and Cartilage Matrix Associated protein/Gla Rich Protein) in phosphate-induced VSMC calcification. We show that Ucma/GRP is present in calcified atherosclerotic plaques and highly expressed in calcifying VSMCs in vitro. VSMCs from Ucma/GRP(-/-) mice showed increased mineralisation and expression of osteo/chondrogenic markers (BMP-2, Runx2, beta-catenin, p-SMAD1/5/8, ALP, OCN), and decreased expression of mineralisation inhibitor MGP, suggesting that Ucma/GRP is an inhibitor of mineralisation. Using BMP signalling inhibitor noggin and SMAD1/5/8 signalling inhibitor dorsomorphin we showed that Ucma/GRP is involved in inhibiting the BMP-2-SMAD1/5/8 osteo/chondrogenic signalling pathway in VSMCs treated with elevated phosphate concentrations. Additionally, we showed for the first time evidence of a direct interaction between Ucma/GRP and BMP-2. These results demonstrate an important role of Ucma/GRP in regulating osteo/chondrogenic differentiation and phosphate-induced mineralisation of VSMCs.NWO ZonMw [MKMD 40-42600-98-13007]; FCT [SFRH/BPD/70277/2010]info:eu-repo/semantics/publishedVersio

    Classification of motor imagery tasks for BCI with multiresolution analysis and multiobjective feature selection

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    Background: Brain-computer interfacing (BCI) applications based on the classification of electroencephalographic (EEG) signals require solving high-dimensional pattern classification problems with such a relatively small number of training patterns that curse of dimensionality problems usually arise. Multiresolution analysis (MRA) has useful properties for signal analysis in both temporal and spectral analysis, and has been broadly used in the BCI field. However, MRA usually increases the dimensionality of the input data. Therefore, some approaches to feature selection or feature dimensionality reduction should be considered for improving the performance of the MRA based BCI. Methods: This paper investigates feature selection in the MRA-based frameworks for BCI. Several wrapper approaches to evolutionary multiobjective feature selection are proposed with different structures of classifiers. They are evaluated by comparing with baseline methods using sparse representation of features or without feature selection. Results and conclusion: The statistical analysis, by applying the Kolmogorov-Smirnoff and Kruskal-Wallis tests to the means of the Kappa values evaluated by using the test patterns in each approach, has demonstrated some advantages of the proposed approaches. In comparison with the baseline MRA approach used in previous studies, the proposed evolutionary multiobjective feature selection approaches provide similar or even better classification performances, with significant reduction in the number of features that need to be computed
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