Neuron-restrictive silencer factor-mediated hyperpolarization-activated cyclic nucleotide gated channelopathy in experimental temporal lobe epilepsy.

ObjectiveEnduring, abnormal expression and function of the ion channel hyperpolarization-activated cyclic adenosine monophosphate gated channel type 1 (HCN1) occurs in temporal lobe epilepsy (TLE). We examined the underlying mechanisms, and investigated whether interfering with these mechanisms could modify disease course.MethodsExperimental TLE was provoked by kainic acid-induced status epilepticus (SE). HCN1 channel repression was examined at mRNA, protein, and functional levels. Chromatin immunoprecipitation was employed to identify the transcriptional mechanism of repressed HCN1 expression, and the basis for their endurance. Physical interaction of the repressor, NRSF, was abolished using decoy oligodeoxynucleotides (ODNs). Video/electroencephalographic recordings were performed to assess the onset and initial pattern of spontaneous seizures.ResultsLevels of NRSF and its physical binding to the Hcn1 gene were augmented after SE, resulting in repression of HCN1 expression and HCN1-mediated currents (I(h) ), and reduced I(h) -dependent resonance in hippocampal CA1 pyramidal cell dendrites. Chromatin changes typical of enduring, epigenetic gene repression were apparent at the Hcn1 gene within a week after SE. Administration of decoy ODNs comprising the NRSF DNA-binding sequence (neuron restrictive silencer element [NRSE]), in vitro and in vivo, reduced NRSF binding to Hcn1, prevented its repression, and restored I(h) function. In vivo, decoy NRSE ODN treatment restored theta rhythm and altered the initial pattern of spontaneous seizures.InterpretationAcquired HCN1 channelopathy derives from NRSF-mediated transcriptional repression that endures via chromatin modification and may provide insight into the mechanisms of a number of channelopathies that coexist with, and may contribute to, the conversion of a normal brain into an epileptic one

Effects of the roots of <i>Cynodon dactylon </i>and <i>Schefflera heptaphylla </i>on water infiltration rate and soil hydraulic conductivity

Water infiltration rate and hydraulic conductivity in vegetated soil are two vital hydrological parameters for agriculturists to determine availability of soil moisture for assessing crop growths and yields, and also for engineers to carry out stability calculations of vegetated slopes. However, any effects of roots on these two parameters are not well-understood. This study aims to quantify the effects of a grass species, Cynodon dactylon, and a tree species, Schefflera heptaphylla, on infiltration rate and hydraulic conductivity in relation to their root characteristics and suction responses. The two selected species are commonly used for ecological restoration and rehabilitation in many parts of the world and South China. A series of in-situ double-ring infiltration tests was conducted during a wet summer, while the responses of soil suction were mointored by tensiometers. When compared to bare soil, the vegetated soil has lower infiltration rate and hydraulic conductivity, due to the clogging of soil pore by plant roots. This results in at least 50% higher suction retained in the vegetated soil. It is revealed that the effects of root-water uptake by the selected species on suction were insignificant due to the small evapotranspiration (&lt; 0.2 mm) when the tests were conducted under the wet climate. There appears to have no significant difference (less than 10%) of infiltration rates, hydraulic conductivity and suction retained between the grass-covered and the tree-covered soil. However, the grass and tree species having deeper root depth and greater Root Area Index (RAI) retained higher suction

An in situ intercomparison exercise on passive samplers for the monitoring of metals, polycyclic aromatic hydrocarbons and pesticides in surface water

An intercomparison exercise on passive samplers (PSs) was organized in summer 2010 for the measurement of selected metals, polycyclic aromatic hydrocarbons (PAHs) and pesticides in surface waters. Various PSs were used and compared at 2 rivers sites and one marine lagoon. A total of 24 laboratories participated. We present selected significant outputs from this exercise, including discussion on quality assurance and quality control for PSs, the interlaboratory variability of field blanks, time weighted average water concentrations and its uncertainties, the representativity of DGT samples, the ability of PSs to lower limits of detection, PAH fingerprints in various PSs compared with spot samples, and the relevance of the permeability reference compounds (PRC) approach for POCIS with pesticides. These in situ intercomparison exercises should enable to progress on the harmonization of practices for the use of passive sampling, especially for priority chemical monitoring and regulatory programs in compliance with the Water Framework Directive (WFD) and Marine Strategy Framework Directive (MSFD)

Effects of root dehydration on biomechanical properties of woody roots of <i>Ulex europaeus</i>

Aims: Effects of root water status on root tensile strength and Young’s modulus were studied in relation to root reinforcement of slopes. Methods: Biomechanical properties of woody roots, Ulex europaeus, were tested during progressive dehydration and after thirty-day moisture equilibration in soil with contrasting water contents. Root diameter, water content and water loss were recorded and root water potential versus water content relation was investigated. Tensile stresses induced by root contraction upon dehydration were measured. Results: Root tensile strength and Young’s modulus increased abruptly when root water content dropped below 0.5 g g −1. The strength increase was due to root radial and axial contraction induced by root water potential drop. Diameter decrease and strength gain were the largest for thin roots because of the relatively larger evaporative surface per volume of thin roots. Largely negative water potentials in dry soil induced root drying, affecting root biomechanical properties. Conclusion: Root water status is a factor that can cause (inappropriately) high strength values and the large variability reported in literature for thin roots. Therefore, all root diameter classes should have consistent moisture for fair comparison. Testing fully hydrated roots should be the routine protocol, given that slope instability occurs after heavy rainfall. </p

Scaling of the reinforcement of soil slopes by living plants in a geotechnical centrifuge

The research described here in was funded by a EPSRC (EP/M020355/1) project in collaboration with the University of Dundee, the University of Southampton, the University of Aberdeen, the Durham University and The James Hutton Institute. The authors thank Professor Mike Humphreys (IBERS, Aberystwyth University) and Scotia seeds for providing seeds used in this study and Dr Gary Callon (University of Dundee) for arranging indoor growing area. The James Hutton Institute receives funding from the Scottish Government (Rural & Environmental Services & Analytical Services Division).Peer reviewedPublisher PD

Relationships between leaf and root area indices and soil suction induced during drying-wetting cycles

The stability and serviceability of geotechnical infrastructure may be affected by plant-induced soil suction during drying-wetting cycles, because an increase in suction would reduce hydraulic conductivity and also increase shear strength. Recent studies have been conducted to quantify suction induced during evapotranspiration (ET) and ponding in soil vegetated with non-crop species that are used for the ecological restoration of geotechnical infrastructure. However, induced suction distribution under drying-wetting cycles has not been investigated. The objectives of this study are to (1) quantify suction induced by a non-crop tree species, Schefflera heptaphylla, under ponding-drying-ponding cycles and (2) correlate intercepted radiant energy, tree leaf area index (LAI), extinction coefficient (k) and root area index (RAI) with suction. In total, 18 vegetated soil samples with LAI ranging from 0.9 to 3.1 and three bare soil samples (control) were tested and subjected to identical cycles of ET and ponding. Energy balance calculation was performed to determine the percentage of interception of radiant energy. An almost linear relationship can be seen between the percentage of energy intercepted (from 7% to 42% ± 4%) and LAI (from 0.9 to 3.1 ± 0.09) for S. heptaphylla. The measured value of k for S. heptaphylla (0.13) was found to be much lower than that of some crop species (0.4-1.6) reported in the literature. Peak suction is always identified at the depth, where RAI is maximum. It was further demonstrated that the tree-induced suction has a strong linear correlation with both the RAI and LAI

Centrifuge modelling of the effects of root geometry on transpiration-induced suction and stability of vegetated slopes

Shallow landslides (i.e., 1 - 2 m depth) on both man-made and natural slopes are of major concern worldwide that has led to huge amount of socio-economical losses. The use of vegetation has been considered as an environmentally friendly means of stabilising slopes. Existing studies have focused on the use of plant roots with different geometries to mechanically stabilise soil slopes, but there are little data available on the contribution of transpiration-induced suction to slope stability. This study was designed to quantify both the hydrological and mechanical effects of root geometry on the stability of shallow slopes. Centrifuge tests were conducted to measure soil suction in slope models supported by newly-developed artificial roots. These artificial roots exhibit three different representative geometries (i.e., tap, heart and plate) and could simulate the effects of transpiration. The measured suction was then back-analysed through a series of finite element seepage-stability analyses to determine the factor of safety (FOS). It is revealed that after a rainfall event with a return period of 1000 years, the slope supported by heart-shaped roots retained the highest suction of 3 kPa within the root depth and thus this type of root provided the greatest stabilisation effects. The FOS of the slope supported by the heart-shaped roots, through both mechanical reinforcement and transpiration-induced suction, is 16% and 28% higher than that supported by the tap- and plate-shaped roots, respectively

Analyse de références architecturales en Flandres

Cette publication comporte une introduction au séminaire de « Critique architecturale contemporaine » tenu par 3 enseignants avec 3 volets méthodologiques distincts. Il est suivi par les articles rédigés par 2 étudiants, Antoine Ghestem et Constance Leduc, lors des visites en Flandre pour leurs études de cas, intégrant ces 3 outils

Uma proposta de plano de marketing para novo modelo de sócio torcedor

Propõe um novo modelo em programa sócio torcedor para clubes brasileiros de grande porte. Apesar de ser uma prática difundida, principalmente no mercado europeu, o Brasil ainda apresenta algumas deficiências neste ambiente mercadológico. O principal desafio é criar um produto diferenciado e inovador,capaz de se inserir no mercado, afim de projetar novos horizontes aos torcedores que buscam uma integração maior com os clubes para os quais torcem. Serão utilizadas referências teóricas de profissionais de marketing conceituados, assim como estudos de outros programas já existentes, tanto no Brasil, quanto internacionais. A partir de então será desenvolvido um plano de marketing para o lançamento do projeto, bem como a construção desta marca e uma suposta aplicação do programa junto ao clube Botafogo Futebol e Regatas