356 research outputs found
On Construction of Tri-Concept Lattices
The main point is to define the structure of a Tri-Concept lattice to deal with data given by different sources and represent it by less complex structures without loosing knowledge. We suggest the algorithm TRI-NEST to form the nested diagrams corresponding to the Tri-Concept lattices. Adding the ICE-T algorithm enables us to generate all frequently closed concepts, which leads to simplifying the Tri-Concept lattices and using the Iceberg Concept lattices as a reduction method to the big data while preserving all information
Two Notes On Modular P-Algebras
According to the definition of congruence .pairs which is given by T. Katrinak, every congruence relation of a modular p-algebra can be uniquely determined by a congruence pair.
In the present paper, we characterize strong extensions of modular p-algebras and permutability of congruences using the congruence pair technique
Predictors of intact and C-terminal fibroblast growth factor 23 in Gambian children
Elevated C-terminal fibroblast growth factor 23 (C-FGF23) concentrations have been reported in Gambian children with and without putative Ca-deficiency rickets. The aims of this study were to investigate whether i) elevated C-FGF23 concentrations in Gambian children persist long term; ii) they are associated with higher intact FGF23 concentrations (I-FGF23), poor iron status and shorter 25-hydroxyvitamin D half-life (25OHD-t1/2); and iii) the persistence and predictors of elevated FGF23 concentrations differ between children with and without a history of rickets. Children (8-16 years, n=64) with a history of rickets and a C-FGF23 concentration >125 RU/ml (bone deformity (BD), n=20) and local community children with a previously measured elevated C-FGF23 concentration (LC+, n=20) or a previously measured C-FGF23 concentration within the normal range (LC-, n=24) participated. BD children had no remaining signs of bone deformities. C-FGF23 concentration had normalised in BD children, but remained elevated in LC+ children. All the children had I-FGF23 concentration within the normal range, but I-FGF23 concentration was higher and iron status poorer in LC+ children. 1,25-dihydroxyvitamin D was the strongest negative predictor of I-FGF23 concentration (R(2)=18%; P=0.0006) and soluble transferrin receptor was the strongest positive predictor of C-FGF23 concentration (R(2)=33%; P≤0.0001). C-FGF23 and I-FGF23 concentrations were poorly correlated with each other (R(2)=5.3%; P=0.07). 25OHD-t1/2 was shorter in BD children than in LC- children (mean (s.d.): 24.5 (6.1) and 31.5 (11.5) days respectively; P=0.05). This study demonstrated that elevated C-FGF23 concentrations normalised over time in Gambian children with a history of rickets but not in local children, suggesting a different aetiology; that children with resolved rickets had a shorter 25OHD-t1/2, suggesting a long-standing increased expenditure of 25OHD, and that iron deficiency is a predictor of elevated C-FGF23 concentrations in both groups of Gambian children
Purification of kappa (k)-carrageenase from locally isolated Cellulosimicrobium cellulans
Partial purification of the crude kappa (k)-carrageenase present in the culture filtrates of Cellulosimicrobium cellulans was carried out by fractional precipitation, using ammonium sulphate, acetone and ethanol individually. The highest recovered protein (37.08%) combined with enzyme activity was obtained with ammonium sulphate. The fraction precipitated by 90% ammonium sulphate was re-purified by anion exchange chromatography diethylaminoethyl (DEAE) cellulose, A-52 and 79 fractions were obtained. The loaded protein was separated into 4 peaks. The third protein peak was the major one which contained the most recovered enzyme activity (84.95%) from the eluted fractions. The collected fractions of this peak were subjected to further purification by re-chromatography on Sephadex G-100. The k-carrageenase activity was fractionated into 2 peaks. The first peak was the major one containing 95.622% of the total recovered activity. The pooled fractions of the major protein component showed a specific k-carrageenase activity of 46.22 U/mg protein, yielding about 4.6 fold purification of the crude enzyme preparation. Some properties of purified k-carrageenase obtained from cellusimicrobium cellulans cultures were studied. The optimum reaction temperature of the purified k-carrageenase was 30°C and the maximum activity occurred at a reaction pH of 6.Key words: Cellulosimicrobium cellulans, k-carrageenase, purification, sephadex G-100, diethylaminoethyl (DEAE) sephadex A-52
Changes in the human peritoneal mesothelial cells during aging
The number of older patients admitted to peritoneal dialysis (PD) programmes is growing. At the same time, there is increasing data about the role of mesothelial cells in determining the functional alteration of the peritoneum during PD. However, little is known about the functional changes accompanying the ageing process in mesothelial cells. We aimed to evaluate whether the aging process is accompanied by changes in some functional characteristic of the human peritoneal mesothelial cells (HPMC), which could account for the poor prognosis observed in old patients with PD. HPMCs were isolated from patients undergoing a nonurgent, nonseptic abdominal surgical procedure, without renal, vascular or inflammatory disease. Cytokine levels (by enzyme-linked immunosorbent assay (ELISA)), nitrates+nitrites, and cyclooxygenase (COX) activity (by a chemiluminescence assay), cytokines, COX, nitric oxide synthase (NOS), and nuclear factor (NF)-κB1, two messenger ribonucleic acid (mRNA) gene expressions (by reverse transcriptase (RT)-Multiplex PCR), COX, and NOS promoter gene activities, and NF-κB-dependent transcription (by transient transfection assays) were determined. Our data show a significant increase in cytokines, COX, and NOS activities, and mRNA expression of cytokines, COX-2, inducible nitric oxide synthase (iNOS) and precursors of NF-κB in HPMCs from old people. This was also the case for COX-2 and iNOS promoter gene activities and NF-κB-dependent transcription. There was a positive correlation between the age of the donor's cell and the proinflammatory profile of the HPMCs. Such age-dependent increase (around two–three times) is partially abolished by different antioxidant or free-radical scavengers. Thus, aging is accompanied by the presence of an inflammatory state in HPMCs, which involves the participation of different reactive oxygen species
Vitamin D expenditure is not altered in pregnancy and lactation despite changes in vitamin D metabolite concentrations.
Pregnancy and lactation are associated with changes in vitamin D and calcium metabolism but the impact of these changes on vitamin D expenditure is unknown. We measured plasma 25(OH)D3 half-life with a stable-isotope tracer and investigated relationships with vitamin D metabolites in pregnant, lactating and 'non-pregnant, non-lactating' (NPNL) women. Vitamin D metabolites, vitamin D binding protein (DBP), PTH and 25(OH)D3 half-life were measured in third-trimester pregnant women (n22) and repeated during lactation 12 weeks post-partum (n14) and twice in NPNL women (n23 and n10, respectively) in rural Gambia where calcium intakes are low with little seasonality in UVB-exposure. 25(OH)D3 half-life was not significantly different between groups (mean(SD): 20.6(6.8), 22.6(7.7), 18.0(4.7) and 17.7(9.5) days in pregnant, lactating and NPNL women, respectively). Plasma 25(OH)D3, 1,25(OH)2D, and DBP were higher in pregnancy, and calculated free-25(OH)D3 and PTH were lower (P < 0.05). In lactation, 25(OH)D3 and 24,25(OH)2D3 were lower compared to pregnant (P < 0.001, P = 0.02) and NPNL women (P = 0.04, P = 0.07). Significant associations were observed between half-life and 25(OH)D3 (+ve) in pregnancy, and in all groups between 25(OH)D3 and free-25(OH)D3 (+ve) and PTH and 25(OH)D3 (-ve) (P < 0.0001). These data suggest that adaptive changes in pregnancy and lactation occur that prevent pronounced changes in vitamin D expenditure
Leader Cells Define Directionality of Trunk, but Not Cranial, Neural Crest Cell Migration.
Collective cell migration is fundamental for life and a hallmark of cancer. Neural crest (NC) cells migrate collectively, but the mechanisms governing this process remain controversial. Previous analyses in Xenopus indicate that cranial NC (CNC) cells are a homogeneous population relying on cell-cell interactions for directional migration, while chick embryo analyses suggest a heterogeneous population with leader cells instructing directionality. Our data in chick and zebrafish embryos show that CNC cells do not require leader cells for migration and all cells present similar migratory capacities. In contrast, laser ablation of trunk NC (TNC) cells shows that leader cells direct movement and cell-cell contacts are required for migration. Moreover, leader and follower identities are acquired before the initiation of migration and remain fixed thereafter. Thus, two distinct mechanisms establish the directionality of CNC cells and TNC cells. This implies the existence of multiple molecular mechanisms for collective cell migration.D11I1096 Fondo de Fomento al Desarrollo Científico y TecnológicoThis is the final version of the article. It first appeared from Cell Press via httsp://doi.org/10.1016/j.celrep.2016.04.06
Kinship, Incentives and Evolution
We analyze how family ties affect incentives, with focus on the strategic interaction between two mutually altruistic siblings. The siblings exert effort to produce output under uncertainty, and they may transfer output to each other. With equally altruistic siblings, their equilibrium effort is non-monotonic in the common degree of altruism, and it depends on the harshness of the environment. We define a notion of local evolutionary stability of degrees of sibling altruism, and show that this degree is lower than the kinship-relatedness factor. Numerical simulations show how family ties vary with the environment, and how this a¤ects economic outcomes
Survey Evidence on Conditional Norm Enforcement
We discuss survey evidence on individuals' willingness to sanction norm violations - such as evading taxes, drunk driving, fare dodging, or skiving o work - by expressing disapproval or social exclusion. Our data suggest that people condition their sanctioning behavior on their belief about the frequency of norm violations. The more commonly a norm violation is believed to occur, the lower the individuals' inclination to punish it. Based on an instrumental variable approach, we demonstrate that this pattern reflects a causal relationship
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