Role of void space geometry in permeability evolution in crustal rocks at elevated pressure

Abstract. Several alteration facies of fractured Lipnice granite are studied in detail on borehole samples by means of mercury intrusion porosimetry, polarized and fluorescent light microscopy and microprobe chemical analyses. The goal is to describe the granite void space geometry in vicinity of fractures with alteration halos and to link specific geometries with simply detectable parameters to facilitate quick estimation of porosity and permeability based on e.g. drill cuttings. The core of the study are results of porosity and throat size distribution analyses on 21 specimens representing unique combinations of fracture-related structures within 6 different alteration facies basically differing in secondary phyllosilicate chemistry and porosity structure. Based on a simple model to calculate permeability from the measured porosities and throat size distributions the difference in permeability between the fresh granite and the most fractured and altered granite is 5 orders of magnitude. Our observations suggest that the porosity, the size of connections and the proportion of crack porosity increase with fracture density, while precipitation of iron-rich infills as well as of fine grained secondary phyllosilicates acts in the opposite way. Different styles and intensities of such end-member agents shape the final void space geometry and imply various combinations of storage, transport and retardation capacity for specific structures. The study also shows the possibility to use the standard mercury intrusion porosimetry with advanced experimental setting and data treatment to distinguish important differences in void space geometry within a span of few per cent of porosity.

Download Full-text

Reassessment of coal permeability evolution using steady-state flow methods: The role of flow regime transition

International Journal of Coal Geology ◽

10.1016/j.coal.2019.103210 ◽

2019 ◽

Vol 211 ◽

pp. 103210 ◽

Cited By ~ 34

Author(s):

Linsen Wang ◽

Zhongwei Chen ◽

Chunguang Wang ◽

Derek Elsworth ◽

Weitao Liu

Keyword(s):

Steady State ◽

Flow Regime ◽

Regime Transition ◽

Permeability Evolution ◽

Steady State Flow ◽

Coal Permeability ◽

State Flow ◽

Flow Regime Transition

Download Full-text

THE INFLUENCE OF HIGH HYDROSTATIC PRESSURE ON COCAINE AND VERATRINE ACTION IN A VERTEBRATE NERVE

The Journal of General Physiology ◽

10.1085/jgp.42.3.647 ◽

1959 ◽

Vol 42 (3) ◽

pp. 647-653 ◽

Cited By ~ 6

Author(s):

Norman L. Gershfeld ◽

Abraham M. Shanes

Keyword(s):

High Pressure ◽

Hydrostatic Pressure ◽

Sciatic Nerve ◽

Action Potential ◽

High Hydrostatic Pressure ◽

Elevated Pressure

The application of high hydrostatic pressure to toad sciatic nerve causes a gain in sodium and a loss of potassium which are not affected by cocaine. However, cocaine action is enhanced by high pressure when counteracting veratrine depolarization and when blocking the action potential. Various effects of elevated pressure on the after-potentials are presented and the role of ions in these processes is discussed.

Download Full-text

The Role of Branch Cell Symmetry and Other Critical Nanoscale Design Parameters in the Determination of Dendrimer Encapsulation Properties

Biomolecules ◽

10.3390/biom10040642 ◽

2020 ◽

Vol 10 (4) ◽

pp. 642 ◽

Cited By ~ 6

Author(s):

Donald A. Tomalia ◽

Linda S. Nixon ◽

David M. Hedstrand

Keyword(s):

Drug Delivery ◽

Metal Cluster ◽

Design Parameters ◽

Void Space ◽

The Past ◽

Cell Symmetry ◽

Family Types ◽

Approved Drugs

This article reviews progress over the past three decades related to the role of dendrimer-based, branch cell symmetry in the development of advanced drug delivery systems, aqueous based compatibilizers/solubilizers/excipients and nano-metal cluster catalysts. Historically, it begins with early unreported work by the Tomalia Group (i.e., The Dow Chemical Co.) revealing that all known dendrimer family types may be divided into two major symmetry categories; namely: Category I: symmetrical branch cell dendrimers (e.g., Tomalia, Vögtle, Newkome-type dendrimers) possessing interior hollowness/porosity and Category II: asymmetrical branch cell dendrimers (e.g., Denkewalter-type) possessing no interior void space. These two branch cell symmetry features were shown to be pivotal in directing internal packing modes; thereby, differentiating key dendrimer properties such as densities, refractive indices and interior porosities. Furthermore, this discovery provided an explanation for unimolecular micelle encapsulation (UME) behavior observed exclusively for Category I, but not for Category II. This account surveys early experiments confirming the inextricable influence of dendrimer branch cell symmetry on interior packing properties, first examples of Category (I) based UME behavior, nuclear magnetic resonance (NMR) protocols for systematic encapsulation characterization, application of these principles to the solubilization of active approved drugs, engineering dendrimer critical nanoscale design parameters (CNDPs) for optimized properties and concluding with high optimism for the anticipated role of dendrimer-based solubilization principles in emerging new life science, drug delivery and nanomedical applications.

Download Full-text

The role of buoyancy in the fate of ultra-high-pressure eclogite

Scientific Reports ◽

10.1038/s41598-019-56475-y ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 6

Author(s):

Timothy Chapman ◽

Geoffrey L. Clarke ◽

Nathan R. Daczko

Keyword(s):

High Pressure ◽

Continental Crust ◽

Upper Mantle ◽

Crustal Rocks ◽

Ultra High Pressure ◽

Rock Types ◽

Mineral Assemblages ◽

Facies Metamorphism ◽

Point Of No Return

AbstractEclogite facies metamorphism of the lithosphere forms dense mineral assemblages at high- (1.6–2.4 GPa) to ultra-high-pressure (>2.4–12 GPa: UHP) conditions that drive slab-pull forces during its subduction to lower mantle conditions. The relative densities of mantle and lithospheric components places theoretical limits for the re-exposure, and peak conditions expected, of subducted lithosphere. Exposed eclogite terranes dominated by rock denser than the upper mantle are problematic, as are interpretations of UHP conditions in buoyant rock types. Their subduction and exposure require processes that overcame predicted buoyancy forces. Phase equilibria modelling indicates that depths of 50–60 km (P = 1.4–1.8 GPa) and 85–160 km (P = 2.6–5 GPa) present thresholds for pull force in end-member oceanic and continental lithosphere, respectively. The point of no-return for subducted silicic crustal rocks is between 160 and 260 km (P = 5.5–9 GPa), limiting the likelihood of stishovite–wadeite–K-hollandite-bearing assemblages being preserved in equilibrated assemblages. The subduction of buoyant continental crust requires its anchoring to denser mafic and ultramafic lithosphere in ratios below 1:3 for the continental crust to reach depths of UHP conditions (85–160 km), and above 2:3 for it to reach extreme depths (>160 km). The buoyant escape of continental crust following its detachment from an anchored situation could carry minor proportions of other rocks that are denser than the upper mantle. However, instances of rocks returned from well-beyond these limits require exceptional exhumation dynamics, plausibly coupled with the effects of incomplete metamorphism to retain less dense low-P phases.

Download Full-text

Increased extracellular pressure enhances cancer cell integrin-binding affinity through phosphorylation of β1-integrin at threonine 788/789

AJP Cell Physiology ◽

10.1152/ajpcell.00355.2008 ◽

2009 ◽

Vol 296 (1) ◽

pp. C193-C204 ◽

Cited By ~ 20

Author(s):

David H. Craig ◽

Christopher P. Gayer ◽

Keri L. Schaubert ◽

Yanzhang Wei ◽

Jinhua Li ◽

...

Keyword(s):

Cell Adhesion ◽

Binding Affinity ◽

Cancer Cell ◽

Elevated Pressure ◽

Colon Cancer Cells ◽

Wild Type ◽

Cancer Cell Adhesion ◽

Integrin Clustering ◽

Murine Fibroblasts

Increased extracellular pressure stimulates β1-integrin-dependent cancer cell adhesion. We asked whether pressure-induced adhesion is mediated by changes in β1-integrin binding affinity or avidity and whether these changes are phosphorylation dependent. We evaluated integrin affinity and clustering in human SW620 colon cancer cells by measuring differences in binding between soluble Arg-Gly-Asp (RGD)-Fc ligands and RGD-Fc-F(ab′)2 multimeric complexes under ambient and 15-mmHg increased pressures. Phosphorylation of β1-integrin S785 and T788/9 residues in SW620 and primary malignant colonocytes was assessed in parallel. We further used GD25-β1-integrin-null murine fibroblasts stably transfected with either wild-type β1A-integrin, S785A, TT788/9AA, or T788D mutants to investigate the role of β1-integrin site-specific phosphorylation. SW620 binding of RGD-Fc-F(ab′)2 multimeric complexes, but not soluble RGD-Fc ligands, was sensitive to integrin clustering. RGD-Fc ligand binding was significantly increased under elevated pressure, suggesting that pressure modulates β1-integrin affinity. Pressure stimulated both β1-integrin S785 and T788/9 phosphorylation. GD25-β1A-integrin wild-type and S785A cells displayed an increase in adhesion to fibronectin under elevated pressure, an effect absent in β1-integrin-null and TT788/9AA cells. T788D substitution significantly elevated basal cell adhesion but displayed no further increase under pressure. These results suggest pressure-induced cell adhesion is mediated by β1-integrin T788/9 phosphorylation-dependent changes in integrin binding affinity.

Download Full-text

Anhydrous ammonioguanidinium(2+) and dihydrated bis[aminoguanidinium(1+)] hexafluorosilicates: new co-products of preparing ferroelectric ammonioguanidinium(2+) hexafluorozirconate

Acta Crystallographica Section B Structural Science ◽

10.1107/s0108768198013044 ◽

1999 ◽

Vol 55 (2) ◽

pp. 246-254 ◽

Cited By ~ 5

Author(s):

C. R. Ross ◽

M. R. Bauer ◽

R. M. Nielson ◽

S. C. Abrahams

Keyword(s):

Water Molecule ◽

Standard Uncertainty ◽

New Materials ◽

Void Space ◽

Packing Efficiency ◽

By Products

Ammonioguanidinium hexafluorosilicate, CH8N_4^{2+}·SiF_6^{2-}, and bis(aminoguanidinium) hexafluorosilicate dihydrate, 2CH7N_4^+·SiF_6^{2-}·2H2O, are new materials formed as by-products in course of preparing ferroelectric CH8N4ZrF6 in the presence of glassware. Their structures were determined for comparison with the corresponding hexafluorozirconates. All atoms including the eight H atoms in the CH8N_4^{2+} cation and the seven H atoms in the CH7N_4^+ cation have been located and refined with wR(F 2) = 0.0653, R = 0.0255, S = 1.146 and wR(F 2) = 0.0745, R = 0.0301, S = 1.065, respectively. The N2C—N—N backbone of the 2+ cation is close to planarity, while that of the 1+ cation does not differ significantly from planarity. The SiF_6^{2-} octahedron is nearly ideally regular in both materials, with <Si—F> = 1.684 (unbiassed estimator of standard uncertainty = 0.016) Å in the anhydrous hexafluorosilicate and 1.6801 (unbiassed estimator of standard uncertainty = 0.0006) Å in the dihydrate. The combination of coulombic and NH...F interactions in CH8N4SiF6 results in a relatively dense variant of the NaCl structure. In addition to similar forces, the dihydrate is also characterized by the role of the water molecule with its strong NH...O interactions; its packing efficiency is, however, appreciably less than that of the anhydrous hexafluorosilicate with an ∼8% increase in void space. Cleaved crystals of the dihydrate are frequently twinned across the (001) composition plane, with a twofold rotation about the b axis as the twin operation.

Download Full-text

Role of gravel substrate on ova survival and alevin emergence of rainbow trout, Salmo gairdneri

Canadian Journal of Zoology ◽

10.1139/z81-092 ◽

1981 ◽

Vol 59 (4) ◽

pp. 629-636 ◽

Cited By ~ 21

Author(s):

Larry D. Witzel ◽

Hugh R. MacCrimmon

Keyword(s):

Rainbow Trout ◽

Incubation Temperature ◽

Salmo Gairdneri ◽

Void Space ◽

Poor Survival ◽

Percent Survival ◽

Gravel Size ◽

Wet Weight ◽

Developmental Condition

The role of gravel size of unigranular diameters 2, 4, 8, 16, and 26.5 mm on ova survival and subsequent emergence of rainbow trout alevins is examined using a vertical-flow incubation apparatus. Survival to emergence, time of emergence, and alevin condition at emergence were signficantly influenced [Formula: see text] by gravel size. Mean percent survival to emergence increased with gravel size from a minimum of 1% in the 2-mm gravel to a maximum of 76% in the 26.5-mm gravel. Survival of control ova from gravel-free incubator was 88% to swim-up stage. Differences in percent survival were most significant within the 2 to 8 mm range. Poor survival of trout alevins in the finer gravels (2–4 mm) was the result of insufficient void space (entrapment). Days to first (43–58 days after ova burial) and 50% emergence (49–62 days after ova burial) also increased with gravel size. At a mean incubation temperature of 10.6 °C, the total emergence days was greatest (40 days) from the 8-mm gravel and occurred prematurely on day 37 after ova burial in 2-mm gravel. Alevin length and weight varied directly with gravel size, ranging from 2.17 to 2.39 cm and 11.9 to 126.8 mg, respectively. Larger alevins, which emerged later from coarser gravels had the least yolk reserve [Formula: see text] and the lowest KD values [Formula: see text], where KD is a developmental condition factor calculated from the ratio of wet weight to standard length. Premature emergence of free embryos and shortening of the alevin îmergence period in 2.0-mm gravel is identified as a stress response.

Download Full-text