Consulta: subjectFacets:"Permeability"
Registros recuperados: 15
Data/hora: 02/06/2024 07:26:06

SPATIAL VARIABILITY OF HYDRAULIC CONDUCTIVITY OF SATURATED SOIL IN CONSERVATION UNIT
Provedor de dados: 196
Autores: Mesquita, Glaucia Machado; Santos, Felipe Corrêa Veloso dos; Dores, Anne Louise; Correchel, Vladia.
The study aimed to evaluate the hydraulic conductivity using soil samples with undisturbed structure in the soil layers of 0-5, 5-10, 10-20, and 20-40 cm; 120 soil samples were collected. For the determination of hydraulic conductivity, the constant load permeameter was used. For geostatistical analysis, exploratory data analysis was performed using frequency histograms, determining the main measures of position and dispersion, verifying the trends for the construction of boxplot graphics, which allows the identification of discrepant points. The lowest and highest hydraulic conductivity values were found in the 20-40 cm and 0-5 cm soil layers, respectively; values commonly found in soils under forest conditions. Based on the results, we conclude when the...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Soil physical quality indicator; Permanent preservation areas; Soil water; Permeability.
Ano: 2022
URL: http://periodicosonline.uems.br/index.php/agrineo/article/view/6532

Germinación en semilla de chile piquín (Capsicum annuum var. aviculare).
Provedor de dados: 32
Autores: Cano Vázquez, Anaid.
El chile piquín es una planta silvestre que presenta ciertos mecanismos para asegurar la perpetuación de la especie. Dentro de estos mecanismos se encuentra la latencia de sus semillas. La germinación de las semillas de chile piquín presenta problemas para siembras  intensivas comerciales. En este trabajo se planteó: 1) comparar diversas colectas en cuanto a su capacidad germinativa; 2) indagar si la baja germinación se debe a impermeabilidad en la semilla o a alguna característica estructural de la semilla; 3) encontrar un tratamiento de preacondicionamiento que mejore la germinación de la semilla y 4) probar la germinación in vitro como un método alternativo para obtener plántula en un corto tiempo. Para prevenir la interferencia de microorganismos...
Palavras-chave: Germinación; Impermeabilidad; Latencia; Desinfección; Germination; Permeability; Dormancy; Disinfection; Fisiología Vegetal; Maestría.
Ano: 2013
URL: http://hdl.handle.net/10521/2114

Caracterização físico-hídrica e hidráulica de solos do bioma Cerrado submetidos a diferentes sistemas de preparo.
Provedor de dados: 14
Autores: SILVA, E. M. da; AZEVEDO, J. A. de; RAUBER, J. C.; REATTO, A.
RESUMO: O plantio direto resulta em impactos positivos na conservação da água no solo. Considerando essa premissa, este trabalho teve o objetivo de avaliar as principais alterações nas propriedades físico-hídricas de solos de Cerrado, decorrentes do uso do plantio direto durante 3, 6 e 12 anos, sob condições de sequeiro e irrigado, em comparação com o plantio convencional e um ambiente de mata natural, na fezenda Ampessan, Cabeceiras, GO. As características físico-hídricas do solo foram avaliadas nas seguintes camadas: 0 a 5 cm; 2,5 a 7,5 cm; 5 a 10 cm; 10 a 15 cm; 20 a 25 cm; 42,5 a 47, 5 cm e 72,5 a 77,5 cm. As características de infiltração nesses ambientes foram avaliadas nas profundidades de 12 a 80 cm, utilizando o método do permeâmetro de Guelph...
Tipo: Boletim de Pesquisa e Desenvolvimento (INFOTECA-E)
Palavras-chave: Plantio convencional; Soil chemicophysical properties; Zero tillage.; Condutividade Hidráulica; Cerrado; Física do Solo; Plantio Direto; Retenção de Água no Solo; Solo.; Permeability; Soil water retention.; Soil.
Ano: 2003
URL: http://www.infoteca.cnptia.embrapa.br/infoteca/handle/doc/568975

Differential bioaccumulation behaviour of Ag and Cd during the early development of the cuttlefish Sepia officinalis
Provedor de dados: 5
Autores: Lacoue Labarthe, T; Warnau, A; Oberhansli, F; Teyssie, J; Koueta, Noussithe; Bustamante, Paco.
Cuttlefish eggs were exposed to background concentrations of dissolved Ag and Cd, using the radiotracers Ag-110m and Cd-109. At different time of the embryonic development (50 days), some eggs were placed in non-contaminating conditions. During the experiment, the uptake and depuration kinetics, and distribution of these metals among the egg compartments (i.e. eggshell, vitellus, peri-vitelline fluid and embryo) were assessed. In parallel, experiments were conducted with sub-lethal concentrations of stable Ag and Cd (2 and 1 mu g l(-1), respectively) to compare the metal behaviour at higher concentrations. From the spawning date up to I month of development, both metals were taken up efficiently by the eggs, reaching load/concentration ratio (LCR) of 1059...
Tipo: Text
Palavras-chave: Cephalopod; Permeability; Eggshell; Embryo; Biokinetics; Silver; Cadmium.
Ano: 2008
URL: http://archimer.ifremer.fr/doc/2008/publication-3882.pdf

Coupled modeling of thermics and hydrogeology with the Cast3M code: application to the Rainbow hydrothermal field (Mid-Atlantic Ridge, 36A degrees 14'N)
Provedor de dados: 5
Autores: Perez, Florian; Muegler, Claude; Jean-baptiste, Philippe; Charlou, Jean-luc.
We present a new numerical tool developed in the Cast3M software framework to model hydrothermal circulation. Thermodynamic properties of one-phase pure water are calculated from the International Association for the Properties of Water and Steam formulation. This new numerical tool is validated on several test cases of convection in closed-top and open-top boxes. Simulations of hydrothermal circulation in a homogeneous-permeability porous medium also give results in good agreement with already published simulations. This new numerical tool is used to construct a geometric and physical conceptual model of the Rainbow vent site at 36A degrees 14(')N on the Mid-Atlantic Ridge. Several configurations are discussed, showing that high temperatures and high mass...
Tipo: Text
Palavras-chave: Hydrothermal system; Mid-ocean ridge; Numerical modeling; Rainbow vent site; Permeability.
Ano: 2013
URL: http://archimer.ifremer.fr/doc/00133/24463/23108.pdf

Interactions between microplastics and phytoplankton aggregates : Impact on their respective fates
Provedor de dados: 5
Autores: Long, Marc; Moriceau, Brivaela; Gallinari, Morgane; Lambert, Christophe; Huvet, Arnaud; Raffray, Jean; Soudant, Philippe.
Plastic debris are resistant to degradation, and therefore tend to accumulate in marine environment. Nevertheless recent estimations of plastic concentrations at the surface of the ocean were lower than expected leading the communities to seek new sinks. Among the different processes suggested we chose to focus on the transport of microplastics from the surface to deeper layers of the ocean via phytoplankton aggregates that constitute most of the sinking flux. Interactions between microplastics and aggregates were studied by building a new device: the flow-through roller tank that mimics the behaviour of laboratory made aggregates sinking through a dense layer of microplastics. Three types of aggregates formed from two different algae species (the diatom...
Tipo: Text
Palavras-chave: Microplastic sink; Vertical export; Diatom and cryptophyte aggregates; Settling rate; Permeability.
Ano: 2015
URL: https://archimer.ifremer.fr/doc/00259/37048/35557.pdf

Comparison of the physical and geotechnical properties of gas-hydrate-bearing sediments from offshore India and other gas-hydrate-reservoir systems
Provedor de dados: 5
Autores: Winters, W. J.; Wilcox-cline, R. W.; Long, P.; Dewri, S. K.; Kumar, P.; Stern, L.; Kerr, L.
The sediment characteristics of hydrate-bearing reservoirs profoundly affect the formation, distribution, and morphology of gas hydrate. The presence and type of gas, porewater chemistry, fluid migration, and subbottom temperature may govern the hydrate formation process, but it is the host sediment that commonly dictates final hydrate habit, and whether hydrate may be economically developed. In this paper, the physical properties of hydrate-bearing regions offshore eastern India (Krishna-Godavari and Mahanadi Basins) and the Andaman Islands, determined from Expedition NGHP-01 cores, are compared to each other, well logs, and published results of other hydrate reservoirs. Properties from the hydrate-free Kerala-Konkan basin off the west coast of India are...
Tipo: Text
Palavras-chave: Physical properties; Gas hydrate; Porosity; Atterberg limits; Consolidation; Permeability; Shear strength; Scanning electron microscopy.
Ano: 2014
URL: https://archimer.ifremer.fr/doc/00289/40036/38799.pdf

Interpretation of the stiffness and permeability of Sand-Kaolin mixtures in the framework of homogenization
Provedor de dados: 42
Autores: Boutin,Claude; Kacprzak,Gregory; Doanh,Thiep.
This study deals with the behaviour of mixtures of sand and saturated kaolin paste considered as composite materials made of permeable and deformable (with non-linear behaviour) matrix (the kaolin paste) with rigid and impervious inclusions (the sand grains). Oedometric and permeability tests conducted on such mixtures highlight the key role of the state of the clay paste, and show the existence of a threshold of sand grain concentration above which a structuring effect influences both modulus and permeability. At the light of these experiments, the usual and tangent homogenization process (with simplifying assumptions to make the problem manageable) has been applied to estimate the mixture permeability and tangent compressibility. Qualitative and...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Homogenization; Non-linear behaviour; Sand-clay mixtures; Permeability; Tangent modulus; Compaction; Hardening.
Ano: 2010
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652010000100017

Influence of thickness on properties of plasticized oat starch films
Provedor de dados: 52
Autores: Galdeano,Melicia Cintia; Wilhelm,Allan Eduardo; Mali,Suzana; Grossmann,Maria Victória Eiras.
The aim of this study was to investigate the effect of thickness (between 80 and 120 µm) on apparent opacity, water vapor permeability and mechanical properties (tensile and puncture) of oat starch films plasticized with glycerol, sorbitol, glycerol:sorbitol mixture, urea and sucrose. Films were stored under 11, 57, 76 and 90% relative humidity (RH) to study the mechanical properties. It was observed that the higher the thickness, the higher was the opacity values. Films without the plasticizer were more opaque in comparison with the plasticized ones. Glycerol:sorbitol films presented increased elongation with increasing thickness at all RH. Puncture force showed a strong dependence on the film thickness, except for the films plasticized with sucrose. In...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Plasticizers; Tensile; Puncture; Permeability; Opacity; Glycerol.
Ano: 2013
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132013000400014

Determination of macromolecular exchange and PO2 in the microcirculation: a simple system for in vivo fluorescence and phosphorescence videomicroscopy
Provedor de dados: 56
Autores: Torres,L.N.; Torres Filho,I.P.
We have developed a system with two epi-illumination sources, a DC-regulated lamp for transillumination and mechanical switches for rapid shift of illumination and detection of defined areas (250-750 µm²) by fluorescence and phosphorescence videomicroscopy. The system permits investigation of standard microvascular parameters, vascular permeability as well as intra- and extravascular PO2 by phosphorescence quenching of Pd-meso-tetra (4-carboxyphenyl) porphine (PORPH). A Pechan prism was used to position a defined region over the photomultiplier and TV camera. In order to validate the system for in vivo use, in vitro tests were performed with probes at concentrations that can be found in microvascular studies. Extensive in vitro evaluations were performed...
Tipo: Info:eu-repo/semantics/other
Palavras-chave: Oxygen; Permeability; Microcirculation; Rat mesentery; Intravital microscopy; Phorphyrin.
Ano: 2001
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2001000100017

ADME studies and preliminary safety pharmacology of LDT5, a lead compound for the treatment of benign prostatic hyperplasia
Provedor de dados: 56
Autores: Noël,F.; Nascimento-Viana,J.B.; Romeiro,L.A.S.; Silva,R.O.; Lemes,L.F.N.; Oliveira,A.S.; Giorno,T.B.S.; Fernandes,P.D.; Silva,C.L.M.
This study aimed to estimate the absorption, distribution, metabolism and excretion (ADME) properties and safety of LDT5, a lead compound for oral treatment of benign prostatic hyperplasia that has previously been characterized as a multi-target antagonist of α1A-, α1D-adrenoceptors and 5-HT1A receptors. The preclinical characterization of this compound comprised the evaluation of its in vitro properties, including plasma, microsomal and hepatocytes stability, cytochrome P450 metabolism and inhibition, plasma protein binding, and permeability using MDCK-MDR1 cells. De-risking and preliminary safety pharmacology assays were performed through screening of 44 off-target receptors and in vivo tests in mice (rota-rod and single dose toxicity). LDT5 is stable in...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Benign prostatic hyperplasia; ADME; Safety; Permeability; CYP; Preclinical development.
Ano: 2016
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2016001200603

An HPLC-UV method for the measurement of permeability of marker drugs in the Caco-2 cell assay
Provedor de dados: 56
Autores: Kratz,J.M.; Teixeira,M.R.; Koester,L.S.; Simões,C.M.O.
The Caco-2 cell line has been used as a model to predict the in vitro permeability of the human intestinal barrier. The predictive potential of the assay relies on an appropriate in-house validation of the method. The objective of the present study was to develop a single HPLC-UV method for the identification and quantitation of marker drugs and to determine the suitability of the Caco-2 cell permeability assay. A simple chromatographic method was developed for the simultaneous determination of both passively (propranolol, carbamazepine, acyclovir, and hydrochlorothiazide) and actively transported drugs (vinblastine and verapamil). Separation was achieved on a C18 column with step-gradient elution (acetonitrile and aqueous solution of ammonium acetate, pH...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Caco-2; HPLC-UV; Marker drugs; Permeability.
Ano: 2011
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2011000600006

The molecular basis of selective permeability of connexins is complex and includes both size and charge
Provedor de dados: 56
Autores: Nicholson,B.J.; Weber,P.A.; Cao,F.; Chang,H.-C.; Lampe,P.; Goldberg,G.
Although gap junction channels are still widely viewed as large, non-specific pores connecting cells, the diversity in the connexin family has led more attention to be focused on their permeability characteristics. We summarize here the current status of these investigations, both published and on-going, that reveal both charge and size selectivity between gap junction channels composed of different connexins. In particular, this review will focus on quantitative approaches that monitor the expression level of the connexins, so that it is clear that differences that are seen can be attributed to channel properties. The degree of selectivity that is observed is modest compared to other channels, but is likely to be significant for biological molecules that...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Intercellular channels; Permeability; Channel selectivity; Gap junctions.
Ano: 2000
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2000000400002

Hypoxia-induced hyperpermeability of rat glomerular endothelial cells involves HIF-2α mediated changes in the expression of occludin and ZO-1
Provedor de dados: 56
Autores: Luo,Peng-Li; Wang,Yan-Jun; Yang,Yan-Yan; Yang,Jia-Jia.
This study aimed to investigate the role of hypoxia-inducible factor-2α (HIF-2α) in the expression of tight junction proteins and permeability alterations in rat glomerular endothelial cells (rGENCs) under hypoxia conditions. The expression level of HIF-2α and tight junction proteins (occludin and ZO-1) in rGENCs were examined following 5% oxygen density exposure at different treatment times. HIF-2α lentivirus transfection was used to knockdown HIF-2α expression. Cells were divided into four groups: 1) control group (rGENCs were cultured under normal oxygen conditions), 2) hypoxia group (rGENCs were cultured under hypoxic conditions), 3) negative control group (rGENCs were infected with HIF-2α lentivirus negative control vectors and cultured under hypoxic...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Hypoxia; HIF-2α; Rat glomerular endothelial cells; Tight junction; Permeability.
Ano: 2018
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2018000700604

Connexin hemichannels and cell-cell channels: comparison of properties
Provedor de dados: 56
Autores: Verselis,V.K.; Trexler,E.B.; Bukauskas,F.F.
Connexin46 (Cx46) forms functional hemichannels in the absence of contact by an apposed hemichannel and we have used these hemichannels to study gating and permeation at the single channel level with high time resolution. Using both cell-attached and -excised patch configurations, we find that single Cx46 hemichannels exhibit some properties expected of half of a gap junction channel, as well as novel properties. Cx46 hemichannels have a large unitary conductance (~300 pS) and a relatively large pore as inferred from permeability to TEA. Both monovalent cations and anions can permeate, but cations are substantially more permeable. The open channel conductance shows marked inward rectification in symmetric salts. We find that the conductance and...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Permeability; Channel gating; Connexin46; Patch clamp.
Ano: 2000
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2000000400003