Belan E.,Royal University
Biology Direct | Year: 2013
LINE-1 (L1) retrotransposons are repetitive elements in mammalian genomes. They are capable of synthesizing DNA on their own RNA templates by harnessing reverse transcriptase (RT) that they encode. Abundantly expressed full-length L1s and their RT are found to globally influence gene expression profiles, differentiation state, and proliferation capacity of early embryos and many types of cancer, albeit by yet unknown mechanisms. They are essential for the progression of early development and the establishment of a cancer-related undifferentiated state. This raises important questions regarding the functional significance of L1 RT in these cell systems. Massive nuclear L1-linked reverse transcription has been shown to occur in mouse zygotes and two-cell embryos, and this phenomenon is purported to be DNA replication independent. This review argues against this claim with the goal of understanding the nature of this phenomenon and the role of L1 RT in early embryos and cancers. Available L1 data are revisited and integrated with relevant findings accumulated in the fields of replication timing, chromatin organization, and epigenetics, bringing together evidence that strongly supports two new concepts. First, noncanonical replication of a portion of genomic full-length L1s by means of L1 RNP-driven reverse transcription is proposed to co-exist with DNA polymerase-dependent replication of the rest of the genome during the same round of DNA replication in embryonic and cancer cell systems. Second, the role of this mechanism is thought to be epigenetic; it might promote transcriptional competence of neighboring genes linked to undifferentiated states through the prevention of tethering of involved L1s to the nuclear periphery. From the standpoint of these concepts, several hitherto inexplicable phenomena can be explained. Testing methods for the model are proposed. © 2013 Belan; licensee BioMed Central Ltd.
Hydraulic diffusivity and macrodispersivity calculations embedded in a geographic information system [Calculs de diffusivité hydraulique et de macro-dispersivité intégrés dans un système d'information géographique]
Pacheco F.A.L.,Royal University
Hydrological Sciences Journal | Year: 2013
A numerical technique is presented whereby aquifer hydraulic diffusivities (D) and macrodispersivities (α) are calculated by linear equations rewritten from flow and solute transport differential equations. The approach requires a GIS to calculate spatial and temporal hydraulic head (h) and solute concentration gradients. The model is tested in Portugal, in a semi-confined aquifer periodically monitored for h and chloride/sulphate concentrations. Average D (0.46 m2/s) and α (1975 m) compare favourably with literature results. The relationship between α and scale (L) is also investigated. In this context, two aquifer groups could be identified: the first group is heterogeneous at the "macroscopic" scale (solute travelled distances <1 km), but homogeneous at the "megascopic" scale. The overall scale dependency in this case is given by an equation of logarithmic type. The second group is heterogeneous at the macroscopic and megascopic scales, with a scale dependency of linear type. © 2013 Copyright 2013 IAHS Press.
Pacheco F.A.L.,Royal University |
Van der Weijden C.H.,University Utrecht
Journal of Hydrology | Year: 2014
Many mountainous watersheds are conceived as aquifer media where multiple groundwater flow systems have developed (Tóth, 1963), and as bimodal landscapes where differential weathering of bare and soil-mantled rock has occurred (Wahrhaftig, 1965). The results of a weathering algorithm (Pacheco and Van der Weijden, 2012a, 2014), which integrates topographic, hydrologic, rock structure and chemical data to calculate weathering rates at the watershed scale, validated the conceptual models in the River Sordo basin, a small watershed located in the Marão cordillera (North of Portugal). The coupling of weathering, groundwater flow and landscape evolution analyses, as accomplished in this study, is innovative and represents a remarkable achievement towards regionalization of rock weathering at the watershed scale. The River Sordo basin occupies an area of approximately 51.2km2 and was shaped on granite and metassediment terrains between the altitudes 185-1300m. The groundwater flow system is composed of recharge areas located at elevations >700m, identified on the basis of δ18O data. Discharge cells comprehend terminations of local, intermediate and regional flow systems, identified on the basis of spring density patterns, infiltration depth estimates based on 87Sr/86Sr data, and spatial distributions of groundwater pH and natural mineralization. Intermediate and regional flow systems, defined where infiltration depths >125m, develop solely along the contact zone between granites and metassediments, because fractures in this region are profound and their density is very large. Weathering is accelerated where rocks are covered by thick soils, being five times faster relative to sectors of the basin where rocks are covered by thin soils. Differential weathering of bare and soil-mantled rock is also revealed by the spatial distribution of calculated aquifer hydraulic diffusivities and groundwater travel times. © 2014 Elsevier B.V.
Perry E.,University of Alberta |
Perry E.,Royal University
Rheumatology (Oxford, England) | Year: 2014
Recent findings have highlighted the potential initiation of ACPA in sites away from the joint. Periodontitis is an example of this concept. This process in the gums appears to be independent of smoking, the main environmental risk factor for ACPA-positive RA. There is extensive literature regarding the potential role of smoking in the pathogenesis of ACPA-positive RA. As a consequence of this strong association, the lung has become the focus of research to determine whether processes within the lung are linked to the generation of ACPA. Here we outline the current body of evidence and explore the hypothesis that the lung as an organ of immune defence has a role in the pathogenesis of the autoimmune disease ACPA-positive RA. © The Author 2014. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For Permissions, please email: email@example.com.
Nobre P.J.,Royal University
Journal of Sexual Medicine | Year: 2010
Introduction.: Recent studies have shown the impact of sexual dysfunctional beliefs, negative cognitive schemas, negative automatic thoughts, and depressed affect on male erectile dysfunction. Despite this fact, there are only few conceptual models that try to integrate these findings, and more importantly, there is a lack of studies that test the validity of those conceptual models. Aim.: The aim of the present article was to test a cognitive-emotional model for erectile dysfunction. Taking previous research findings into account, we developed a cognitive-emotional model for erectile disorder (ED) and used path analysis to test it. Methods.: A total of 352 men (303 participants from the general population and 49 participants with a DSM-IV diagnosis of sexual dysfunction) answered a set of questionnaires assessing cognitive and emotional variables. Main Outcome Measures.: Erectile Function measured by the EF subscale of the International Index of Erectile Function, cognitive schemas measured by the Questionnaire of Cognitive Schema Activation in Sexual Context, sexual beliefs measured by the Sexual Dysfunctional Beliefs Questionnaire, thoughts and emotions measured by the Sexual Modes Questionnaire. Results.: The effects of the main proposed direct predictors explained 55% of the erectile function variance (R = 0.74). Most remaining direct effects proposed in the model were also statistically significant. The analysis of the absolute residuals showed that most of the implied correlations were close to the observed zero order correlations, indicated the adjustment of the model to the observed data. Conclusions.: These findings support the role played by cognitive and emotional factors on the predisposition and maintenance of male erectile dysfunction and suggest important implications for assessment and treatment of ED. Nobre PJ. Psychological determinants of erectile dysfunction: Testing a cognitive-emotional model. © 2010 International Society for Sexual Medicine.
Pacheco F.A.L.,Royal University
Science of the Total Environment | Year: 2015
The territory of continental Portugal has a geologic history marked by the Hercynian orogeny, and to the north of this country the Hercynian large-scale tectonic structures are typically represented by long and deep NW-SE trending ductile shear zones and NNE-SSW trending fragile faults. These structures are elements of mineral and thermal water circuits that discharge as springs in more than one hundred locations. The purpose of this study is to investigate if these structures are also used by shallower non-mineral groundwater, integrated in a large-scale regional flow system. Using an original combination of water balance and recession flow models, it was possible to calculate catchment turnover times based solely on groundwater discharge rates and recession flow parameters. These times were then used to classify a group of 46 watersheds as closed or open basins, and among the later class to identify source and sink basins, based on innovative interpretations of relationships between turnover time and catchment area. By definition, source basins transfer groundwater to sink basins and altogether form a regional flow system. Using a Geographic Information System, it could be demonstrated the spatial association of open basins to the Hercynian ductile and fragile tectonic structures and hence to classify the basins as discharge cells of a regional flow system. Most of the studied watersheds are sub-basins of the Douro River basin, one of the largest regional catchments in the Iberian Peninsula, being located in its mouth area. Because the largest part of open basins is sink, which by definition tends to dominate in the mouth area of regional catchments, it is proposed as an extension of the studied area conceptual boundaries towards the Douro River basin headwaters, where the corresponding sources could be searched for. © 2014 Elsevier B.V.
Royal University | Date: 2014-11-14
A bionanofluid includes a carbon-based nanomaterial substantially mono-dispersed in a fluid. The carbon-based nanomaterial is surface modified with a polar group when the fluid is polar or with a non-polar group when the fluid is non-polar, and functionalized with a biological targeting moiety to allow specific association of the carbon-based nanomaterial to a targeted entity. A hybrid bionanofluid includes the bionanofluid, with the carbon-based nanomaterial further modified with a hybrid nanoparticle which includes an alloy, transition metal, semi-conductor, semi-metal or polymer based nanoparticle with biological targeting moiety. A hydrogel, foam, cream, spray or dried product includes the bionanofluid or hybrid bionanofluid. The bionanofluid or hybrid bionanofluid are useful in multimodal imaging (photo-luminescence, luminescence, photo-acoustic, MRI, ultrasound) and/or cellular targeting.
Gandarias M.L.,Royal University
Journal of Physics A: Mathematical and Theoretical | Year: 2011
The concepts of self-adjoint and quasi self-adjoint equations were introduced by Ibragimov (2006 J. Math. Anal. Appl. 318 742-57; 2007 Arch. ALGA 4 55-60). In Ibragimov (2007 J. Math. Anal. Appl. 333 311-28), a general theorem on conservation laws was proved. In this paper, we generalize the concept of self-adjoint and quasi self-adjoint equations by introducing the definition of weak self-adjoint equations. We find a class of weak self-adjoint quasi-linear parabolic equations. The property of a differential equation to be weak self-adjoint is important for constructing conservation laws associated with symmetries of the differential equation. © 2011 IOP Publishing Ltd.
Royal University | Date: 2014-07-11
The present disclosure concerns the determination of the resistance or the susceptibility of a nematode to an imidazothiazole anti-helmintic based on the assessment of the presence of an indel in the Hco-acr-8 gene (or the Hco-acr-8 gene ortholog). The present disclosure also provides tools and commercial packages for making such assessment.
Royal University | Date: 2013-02-22
An energy-extracting mine ventilation system comprises: a ventilation unit for conditioning the intake air of a mine; a network of pipes installed in at least one cavity of the mine, the network of pipes comprising a geothermal fluid circulating therethrough wherein the network is in contact with a minefill material within the cavity and a rock mass; wherein the minefill material transfers energy between the rock mass of the at least one cavity and the thermal fluid; and a heat exchanger unit in fluid communication with the network of pipes and extracting the energy from the thermal fluid The heat exchanger unit is configured to transfer extracted energy directly or indirectly to the ventilation unit in order to condition the intake air of the mine, The extracted energy can be used in a variety of other applications, such as district heating, acid leaching, and water heating.