Gross, histological and ultrastructural morphology of the aglomerular kidney in the lined seahorse Hippocampus erectus.

PubMed

Fogelson, S B; Yanong, R P E; Kane, A; Teal, C N; Berzins, I K; Smith, S A; Brown, C; Camus, A

2015-09-01

Histologic evaluation of the renal system in the lined seahorse Hippocampus erectus reveals a cranial kidney with low to moderate cellularity, composed of a central dorsal aorta, endothelial lined capillary sinusoids, haematopoietic tissue, fine fibrovascular stroma, ganglia and no nephrons. In comparison, the caudal kidney is moderately to highly cellular with numerous highly convoluted epithelial lined tubules separated by interlacing haematopoietic tissue, no glomeruli, fine fibrovascular stroma, numerous capillary sinusoids, corpuscles of Stannius and clusters of endocrine cells adjacent to large calibre vessels. Ultrastructural evaluation of the renal tubules reveals minimal variability of the tubule epithelium throughout the length of the nephron and the majority of tubules are characterized by epithelial cells with few apical microvilli, elaborate basal membrane infolding, rare electron dense granules and abundant supporting collagenous matrix. © 2015 The Fisheries Society of the British Isles.

A Composite Medium Approximation for Moisture Tension-Dependent Anisotropy in Unsaturated Layered Sediments

NASA Astrophysics Data System (ADS)

Pruess, K.

2001-12-01

Sedimentary formations often have a layered structure in which hydrogeologic properties have substantially larger correlation length in the bedding plane than perpendicular to it. Laboratory and field experiments and observations have shown that even small-scale layering, down to millimeter-size laminations, can substantially alter and impede the downward migration of infiltrating liquids, while enhancing lateral flow. The fundamental mechanism is that of a capillary barrier: at increasingly negative moisture tension (capillary suction pressure), coarse-grained layers with large pores desaturate more quickly than finer-grained media. This strongly reduces the hydraulic conductivity of the coarser (higher saturated hydraulic conductivity) layers, which then act as barriers to downward flow, forcing water to accumulate and spread near the bottom of the overlying finer-grained material. We present a "composite medium approximation" (COMA) for anisotropic flow behavior on a typical grid block scale (0.1 - 1 m or larger) in finite-difference models. On this scale the medium is conceptualized as consisting of homogeneous horizontal layers with uniform thickness, and capillary equilibrium is assumed to prevail locally. Directionally-dependent relative permeabilities are obtained by considering horizontal flow to proceed via "conductors in parallel," while vertical flow involves "resistors in series." The model is formulated for the general case of N layers, and implementation of a simplified two-layer (fine-coarse) approximation in the multiphase flow simulator TOUGH2 is described. The accuracy of COMA is evaluated by comparing numerical simulations of plume migration in 1-D and 2-D unsaturated flow with results of fine-grid simulations in which all layers are discretized explicitly. Applications to water seepage and solute transport at the Hanford site are also described. This work was supported by the U.S. Department of Energy under Contract No. DE-AC03-76SF00098 through Memorandum Purchase Order 248861-A-B2 between Pacific Northwest National Laboratory and Lawrence Berkeley National Laboratory.

Continuous-Flow Electrophoresis of DNA and Proteins in a Two-Dimensional Capillary-Well Sieve.

PubMed

Duan, Lian; Cao, Zhen; Yobas, Levent

2017-09-19

Continuous-flow electrophoresis of macromolecules is demonstrated using an integrated capillary-well sieve arranged into a two-dimensional anisotropic array on silicon. The periodic array features thousands of entropic barriers, each resulting from an abrupt interface between a 2 μm deep well (channel) and a 70 nm capillary. These entropic barriers owing to two-dimensional confinement within the capillaries are vastly steep in relation to those arising from slits featuring one-dimensional confinement. Thus, the sieving mechanisms can sustain relatively large electric field strengths over a relatively small array area. The sieve rapidly sorts anionic macromolecules, including DNA chains and proteins in native or denatured states, into distinct trajectories according to size or charge under electric field vectors orthogonally applied. The baseline separation is achieved in less than 1 min within a horizontal migration length of ∼1.5 mm. The capillaries are self-enclosed conduits in cylindrical profile featuring a uniform diameter and realized through an approach that avoids advanced patterning techniques. The approach exploits a thermal reflow of a layer of doped glass for shape transformation into cylindrical capillaries and for controllably shrinking the capillary diameter. Lastly, atomic layer deposition of alumina is introduced for the first time to fine-tune the capillary diameter as well as to neutralize the surface charge, thereby suppressing undesired electroosmotic flows.

The Impact of Multiple Freeze-Thaw Cycles on the Microstructure of Aggregates from a Soddy-Podzolic Soil: A Microtomographic Analysis

NASA Astrophysics Data System (ADS)

Skvortsova, E. B.; Shein, E. V.; Abrosimov, K. N.; Romanenko, K. A.; Yudina, A. V.; Klyueva, V. V.; Khaidapova, D. D.; Rogov, V. V.

2018-02-01

With the help of computed X-ray microtomography with a resolution of 2.75 μm, changes in the microstructure and pore space of aggregates of 3 mm in diameter from the virgin soddy-podzolic soil (Glossic Retisol (Loamic)) in the air-dry, capillary-moistened, and frozen states after five freeze-thaw cycles were studied in a laboratory experiment. The freezing of the samples was performed at their capillary moistening. It was shown that capillary moistening of initially air-dry samples from the humus (AY), eluvial (EL), and illuvial (BT1) horizons at room temperature resulted in the development of the platy, fine vesicular, and angular blocky microstructure, respectively. The total volume of tomographically visible pores >10 μm increased by 1.3, 2.2, and 3.4 times, respectively. After freeze-thaw cycles, frozen aggregates partly preserved the structural arrangement formed during the capillary moistening. At the same time, in the frozen aggregate from the AY horizon, the total tomographic porosity decreased to the initial level of the air-dry soil. In the frozen aggregate from the EL horizon, large vesicular pores were formed, owing to which the total pore volume retained its increased values. The resistance of aggregate shape to the action of freeze-thaw cycles differed. The aggregate from the EL horizon completely lost its original configuration by the end of the experiment. The aggregate from the AY horizon displayed definite features of sagging after five freeze-thaw cycles, whereas the aggregate from the BT1 horizon preserved its original configuration.

On the performance of capillary barriers as landfill cover

NASA Astrophysics Data System (ADS)

Kämpf, M.; Montenegro, H.

Landfills and waste heaps require an engineered surface cover upon closure. The capping system can vary from a simple soil cover to multiple layers of earth and geosynthetic materials. Conventional design features a compacted soil layer, which suffers from drying out and cracking, as well as root and animal intrusion. Capillary barriers consisting of inclined fine-over-coarse soil layers are investigated as an alternative cover system. Under unsaturated conditions, the textural contrast delays vertical drainage by capillary forces. The moisture that builds up above the contact will flow downdip along the interface of the layers. Theoretical studies of capillary barriers have identified the hydraulic properties of the layers, the inclination angle, the length of the field and the infiltration rate as the fundamental characteristics of the system. However, it is unclear how these findings can lead to design criteria for capillary barriers. To assess the uncertainty involved in such approaches, experiments have been carried out in a 8 m long flume and on large scale test sites (40 m x 15 m). In addition, the ability of a numerical model to represent the relevant flow processes in capillary barriers has been examined.

Investigating the influence of lithologic heterogeneity on gas hydrate formation and methane recycling at the base of the gas hydrate stability zone in channelized systems

NASA Astrophysics Data System (ADS)

Daigle, H.; Nole, M.; Cook, A.; Malinverno, A.

2017-12-01

In marine environments, gas hydrate preferentially accumulates in coarse-grained sediments. At the meso- to micro-scale, however, hydrate distribution in these coarse-grained units is often heterogeneous. We employ a methane hydrate reservoir simulator coupling heat and mass transfer as well as capillary effects to investigate how capillary controls on methane solubility affect gas and hydrate accumulations in reservoirs characterized by graded bedding and alternating sequences of coarse-grained sands and fine-grained silt and clay. Simulations bury a channelized reservoir unit encased in homogeneous, fine-grained material characterized by small pores (150 nm) and low permeability ( 1 md in the absence of hydrate). Pore sizes within each reservoir bed between vary between coarse sand and fine silt. Sands have a median pore size of 35 microns and a lognormal pore size distribution. We also investigate how the amount of labile organic carbon (LOC) affects hydrate growth due to microbial methanogenesis within the sediments. In a diffusion-dominated system, methane movies into reservoir layers along spatial gradients in dissolved methane concentration. Hydrate grows in such a way as to minimize these concentration gradients by accumulating slower in finer-grained reservoir layers and faster in coarser-grained layers. Channelized, fining-upwards sediment bodies accumulate hydrate first along their outer surfaces and thence inward from top to bottom. If LOC is present in thin beds within the channel, higher saturations of hydrate will be distributed more homogeneously throughout the unit. When buried beneath the GHSZ, gas recycling can occur only if enough hydrate is present to form a connected gas phase upon dissociation. Simulations indicate that this is difficult to achieve for diffusion-dominated systems, especially those with thick GHSZs and/or small amounts of LOC. However, capillary-driven fracturing behavior may be more prevalent in settings with thick GHSZs.

Investigating the influence of lithologic heterogeneity on gas hydrate formation and methane recycling at the base of the gas hydrate stability zone in channelized systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Daigle, Hugh; Nole, Michael; Cook, Ann

In marine environments, gas hydrate preferentially accumulates in coarse-grained sediments. At the meso- to micro-scale, however, hydrate distribution in these coarse-grained units is often heterogeneous. We employ a methane hydrate reservoir simulator coupling heat and mass transfer as well as capillary effects to investigate how capillary controls on methane solubility affect gas and hydrate accumulations in reservoirs characterized by graded bedding and alternating sequences of coarse-grained sands and fine-grained silt and clay. Simulations bury a channelized reservoir unit encased in homogeneous, fine-grained material characterized by small pores (150 nm) and low permeability (~1 md in the absence of hydrate). Poremore » sizes within each reservoir bed between vary between coarse sand and fine silt. Sands have a median pore size of 35 microns and a lognormal pore size distribution. We also investigate how the amount of labile organic carbon (LOC) affects hydrate growth due to microbial methanogenesis within the sediments. In a diffusion-dominated system, methane movies into reservoir layers along spatial gradients in dissolved methane concentration. Hydrate grows in such a way as to minimize these concentration gradients by accumulating slower in finer-grained reservoir layers and faster in coarser-grained layers. Channelized, fining-upwards sediment bodies accumulate hydrate first along their outer surfaces and thence inward from top to bottom. If LOC is present in thin beds within the channel, higher saturations of hydrate will be distributed more homogeneously throughout the unit. When buried beneath the GHSZ, gas recycling can occur only if enough hydrate is present to form a connected gas phase upon dissociation. Simulations indicate that this is difficult to achieve for diffusion-dominated systems, especially those with thick GHSZs and/or small amounts of LOC. However, capillary-driven fracturing behavior may be more prevalent in settings with thick GHSZs.« less

Structure of Particle Networks in Capillary Suspensions with Wetting and Nonwetting Fluids

PubMed Central

2016-01-01

The mechanical properties of a suspension can be dramatically altered by adding a small amount of a secondary fluid that is immiscible with the bulk phase. The substantial changes in the strength of these capillary suspensions arise due to the capillary force inducing a percolating particle network. Spatial information on the structure of the particle networks is obtained using confocal microscopy. It is possible, for the first time, to visualize the different types of percolating structures of capillary suspensions in situ. These capillary networks are unique from other types of particulate networks due to the nature of the capillary attraction. We investigate the influence of the three-phase contact angle on the structure of an oil-based capillary suspension with silica microspheres. Contact angles smaller than 90° lead to pendular networks of particles connected with single capillary bridges or clusters comparable to the funicular state in wet granular matter, whereas a different clustered structure, the capillary state, forms for angles larger than 90°. Particle pair distribution functions are obtained by image analysis, which demonstrate differences in the network microstructures. When porous particles are used, the pendular conformation also appears for apparent contact angles larger than 90°. The complex shear modulus can be correlated to these microstructural changes. When the percolating structure is formed, the complex shear modulus increases by nearly three decades. Pendular bridges lead to stronger networks than the capillary state network conformations, but the capillary state clusters are nevertheless much stronger than pure suspensions without the added liquid. PMID:26807651

Tuning and Freezing Disorder in Photonic Crystals using Percolation Lithography.

PubMed

Burgess, Ian B; Abedzadeh, Navid; Kay, Theresa M; Shneidman, Anna V; Cranshaw, Derek J; Lončar, Marko; Aizenberg, Joanna

2016-01-21

Although common in biological systems, synthetic self-assembly routes to complex 3D photonic structures with tailored degrees of disorder remain elusive. Here we show how liquids can be used to finely control disorder in porous 3D photonic crystals, leading to complex and hierarchical geometries. In these optofluidic crystals, dynamically tunable disorder is superimposed onto the periodic optical structure through partial wetting or evaporation. In both cases, macroscopic symmetry breaking is driven by subtle sub-wavelength variations in the pore geometry. These variations direct site-selective infiltration of liquids through capillary interactions. Incorporating cross-linkable resins into our liquids, we developed methods to freeze in place the filling patterns at arbitrary degrees of partial wetting and intermediate stages of drying. These percolation lithography techniques produced permanent photonic structures with adjustable disorder. By coupling strong changes in optical properties to subtle differences in fluid behavior, optofluidic crystals may also prove useful in rapid analysis of liquids.

Increased Durability of Concrete Made with Fine Recycled Concrete Aggregates Using Superplasticizers.

PubMed

Cartuxo, Francisco; de Brito, Jorge; Evangelista, Luis; Jiménez, José Ramón; Ledesma, Enrique F

2016-02-08

This paper evaluates the influence of two superplasticizers (SP) on the durability properties of concrete made with fine recycled concrete aggregate (FRCA). For this purpose, three families of concrete were tested: concrete without SP, concrete made with a regular superplasticizer and concrete made with a high-performance superplasticizer. Five volumetric replacement ratios of natural sand by FRCA were tested: 0%, 10%, 30%, 50% and 100%. Two natural gravels were used as coarse aggregates. All mixes had the same particle size distribution, cement content and amount of superplasticizer. The w/c ratio was calibrated to obtain similar slump. The results showed that the incorporation of FRCA increased the water absorption by immersion, the water absorption by capillary action, the carbonation depth and the chloride migration coefficient, while the use of superplasticizers highly improved these properties. The incorporation of FRCA jeopardized the SP's effectiveness. This research demonstrated that, from a durability point of view, the simultaneous incorporation of FRCA and high-performance SP is a viable sustainable solution for structural concrete production.

Sub-mm Scale Fiber Guided Deep/Vacuum Ultra-Violet Optical Source for Trapped Mercury Ion Clocks

NASA Technical Reports Server (NTRS)

Yi, Lin; Burt, Eric A.; Huang, Shouhua; Tjoelker, Robert L.

2013-01-01

We demonstrate the functionality of a mercury capillary lamp with a diameter in the sub-mm range and deep ultraviolet (DUV)/ vacuum ultraviolet (VUV) radiation delivery via an optical fiber integrated with the capillary. DUV spectrum control is observed by varying the fabrication parameters such as buffer gas type and pressure, capillary diameter, electrical resonator design, and temperature. We also show spectroscopic data of the 199Hg+ hyper-fine transition at 40.5GHz when applying the above fiber optical design. We present efforts toward micro-plasma generation in hollow-core photonic crystal fiber with related optical design and theoretical estimations. This new approach towards a more practical DUV optical interface could benefit trapped ion clock developments for future ultra-stable frequency reference and time-keeping applications.

FIELD SAMPLING OF RESIDUAL AVIATION GASOLINE IN SANDY SOIL

EPA Science Inventory

Two complimentary field sampling methods for the determination of residual aviation gasoline content in the contaminated capillary fringe of a fine, uniform, sandy soil were investigated. The first method featured filed extrusion of core barrels into pint size Mason jars, while ...

Liquid metal angiography for mega contrast X-ray visualization of vascular network in reconstructing in-vitro organ anatomy.

PubMed

Wang, Qian; Yu, Yang; Pan, Keqin; Liu, Jing

2014-07-01

Visualization on the anatomical vessel networks plays a vital role in the physiological or pathological investigations. However, so far it still remains a big challenge to identify the fine structures of the smallest capillary vessel networks via conventional imaging ways. Here, the room temperature liquid metal angiography was proposed for the first time to generate mega contrast X-ray images for multiscale vasculature mapping. Particularly, gallium was adopted as the room temperature liquid metal contrast agent and infused into the vessels of in vitro pig hearts and kidneys. We scanned the samples under X-ray and compared the angiograms with those obtained via conventional contrast agent--the iohexol. As quantitatively demonstrated by the grayscale histograms and numerical indexes, the contrast of the vessels to the surrounding tissues in the liquid metal angiograms is orders higher than that of the iohexol enhanced images. And the angiogram has reached detailed enough width of 0.1 mm for the tiny vessels, which indicated that the capillaries can be clearly distinguished under the liquid metal enhanced images. Further, with tomography from the micro-CT, we also managed to reconstruct the 3-D structures of the kidney vessels. Tremendous clarity and efficiency of the method over existing approaches have been experimentally clarified. It was disclosed that the usually invisible capillary networks now become distinctively clear in the gallium angiograms. This basic mechanism has generalized purpose and can be extended to a wide spectrum of 3-D computational tomographic areas. It opens a new soft tool for quickly reconstructing high-resolution spatial channel networks for scientific researches as well as engineering practices where complicated and time-consuming resections are no longer a necessity.

Model of formation of droplets during electric arc surfacing of functional coatings

NASA Astrophysics Data System (ADS)

Sarychev, Vladimir D.; Granovskii, Alexei Yu; Nevskii, Sergey A.; Gromov, Victor E.

2016-01-01

The mathematical model was developed for the initial stage of formation of an electrode metal droplet in the process of arc welding. Its essence lies in the fact that the presence of a temperature gradient in the boundary layer of the molten metal causes thermo-capillary instability, which leads to the formation of electrode metal droplets. A system of equations including Navier-Stokes equations, heat conduction and Maxwell's equations was solved as well as the boundary conditions for the system electrodes-plasma. Dispersion equation for thermo-capillary waves in the linear approximation for the plane layer was received and analyzed. The values of critical wavelengths, at which thermo-capillary instability appears in the nanometer wavelength range, were found. The parameters at which the mode of a fine-droplet transfer of the material takes place were theoretically defined.

Palladium-zinc catalysts on mesoporous titania prepared by colloid synthesis. II. Synthesis and characterization of PdZn/TiO2 coating on inner surface of fused silica capillary

NASA Astrophysics Data System (ADS)

Okhlopkova, Lyudmila B.; Kerzhentsev, Michail A.; Tuzikov, Fedor V.; Larichev, Yurii V.; Ismagilov, Zinfer R.

2012-09-01

Nanoparticle-doped mesoporous titania coating was synthesized by incorporation of PdZn nanoparticles into TiO2 sol followed by dip coating of the sol on inner surface of fused silica capillary. Monodispersed PdZn bimetallic colloidal particles with average particle diameters of approximately 2 nm have been prepared by an ethylene glycol reduction of ZnCl2 and Pd(CH3COO)2 in the presence of polyvinylpyrrolidone. The textural properties, surface structure, chemical composition, and morphology of the samples were investigated by means of N2 sorption measurements, TEM, and X-ray diffraction. PdZn/TiO2 coating has been further analyzed by quantitative analysis of the SAXS data in combination with the density contrast method, providing direct structural-dispersion information about the active component and support. Calcination conditions suitable for surfactant removal have been optimized to obtain PdZn/TiO2 coatings with required metal particle size and composition. The high dispersion and chemical composition of the nanoparticles embedded in mesoporous titania coating have been retained with no modification after thermal treatment in vacuum at 300 °C. Results suggest how porous structure of the PdZn coating may be fine-tuned to improve the accessibility of the pores to reactants. The control of the pore size in the range of 4.9-6.8 nm of the mesoporous titania was achieved by adding co-surfactants, such as n-butanol.

Narrow band imaging in the diagnosis of intra-epithelial and invasive laryngeal squamous cell carcinoma: a preliminary report of two cases.

PubMed

Masaki, Takashi; Katada, Chikatoshi; Nakayama, Meijin; Takeda, Masahiko; Miyamoto, Shunsuke; Seino, Yutomo; Koizumi, Wasaburo; Tanabe, Satoshi; Horiguchi, Satoshi; Okamoto, Makito

2009-12-01

Narrow band imaging (NBI) is a novel optical technique that enhances the diagnostic capability of the gastrointestinal endoscope (GIE) by illuminating the intraepithelial papillary capillary loop (IPCL) using narrow bandwidth filters in a red-green-blue sequential illumination system (CV-260SL processor and CLV-260SL light source, Olympus Optical Co. Ltd, Tokyo, Japan). The NBI filter sets (415 nm and 540 nm) are selected to obtain fine images of the microvascular structure. Because 415 nm is the hemoglobin absorption band, capillaries on the mucosal surface can be seen most clearly at this wavelength. NBI is able to represent more clearly both capillary patterns and the boundary between different types of tissue, which are necessary for diagnosing a tumor in its early stage (Gono K, Yamazaki K, Doguchi N, Nonami T, Obi T, Yamaguchi M, et al. Endoscopic observation of tissue by narrow band illumination. Opt Rev 2003;10:211-215, Gono K, Obi T, Yamaguchi M, Ohyama N, Machida H, Sano Y, et al. Appearance of enhanced tissue feature in narrow-band endoscopic imaging. J Biomed Opt 2004;9:568-577). We present two patients with laryngeal squamous cell carcinoma in whom the spread and the depth of invasion was evaluated with transnasal GIE equipped with NBI. Based on our results, the vascular neoplastic changes of carcinoma in situ of the larynx could be similar to carcinoma in situ of the esophagus.

Applications of nuclear magnetic resonance spectroscopy for the understanding of enantiomer separation mechanisms in capillary electrophoresis.

PubMed

Salgado, Antonio; Chankvetadze, Bezhan

2016-10-07

This review deals with the applications of nuclear magnetic resonance (NMR) spectroscopy to understand the mechanisms of chiral separation in capillary electrophoresis (CE). It is accepted that changes observed in the separation process, including the reversal of enantiomer migration order (EMO), can be caused by subtle modifications in the molecular recognition mechanisms between enantiomer and chiral selector. These modifications may imply minor structural differences in those selector-selectand complexes that arise from the above mentioned interactions. Therefore, it is mandatory to understand the fine intermolecular interactions between analytes and chiral selectors. In other words, it is necessary to know in detail the structures of the complexes formed by the enantiomer (selectand) and the selector. Any differences in the structures of these complexes arising from either enantiomer should be detected, so that enantiomeric bias in the separation process could be explained. As to the nature of these interactions, those have been extensively reviewed, and it is not intended to be discussed here. These interactions contemplate ionic, ion-dipole and dipole-dipole interactions, hydrogen bonding, van der Waals forces, π-π stacking, steric and hydrophobic interactions. The main subject of this review is to describe how NMR spectroscopy helps to gain insight into the non-covalent intermolecular interactions between selector and selectand that lead to enantiomer separation by CE. Examples in which diastereomeric species are created by covalent (irreversible) derivatization will not be considered here. This review is structured upon the different structural classes of chiral selectors employed in CE, in which NMR spectroscopy has made substantial contributions to rationalize the observed enantioseparations. Cases in which other techniques complement NMR spectroscopic data are also mentioned. Copyright © 2016 Elsevier B.V. All rights reserved.

Fabrication and transport property of artificial structure of CNTs using SPM nano-manipulation

NASA Astrophysics Data System (ADS)

Maejima, K.; Kida, M.; Yaguchi, Y.; Sudo, K.; Kawamura, T.; Morimoto, T.; Aoki, N.; Ochiai, Y.

2007-04-01

We have established a novel manipulation technique using a glass-micro capillary under a high-resolution CCD microscope so far. Two isolated multi-wall carbon nanotubes (MWNTs) are settled to form a well-aligned cross structure. Recently, we have tried to develop a fine manipulation system using a scanning probe microscope with a silicon cantilever. Therefore, thinner high-quality MWNTs (˜10 nm in diameter) can be utilized in this system. At the junction, we have observed weak localization and Fano-like-effect, zero bias anomaly whose traces were visible even at room temperature with thick MWNTs (˜100 nm in diameter). On the other hand, with thinner high-quality MWNTs (˜10 nm in diameter), we have observed also anomalous I-V characteristic and Altshuler-Aronov-Spivak-like magneto-oscillations at low temperature in the nano-space transport.

Use of tapered Pyrex capillary tubes to increase the mechanical stability of multiwall carbon nanotubes field emitters

NASA Astrophysics Data System (ADS)

Mousa, M. S.; Bani Ali, E. S.; Hagmann, M. J.

2018-02-01

In this study, NanocylTM NC 7000 Thin Multiwall Carbon Nanotubes (MWCNTs) were used with a high aspect ratio (>150) made by the process of catalytic chemical vapor deposition (CCVD). The field emitter tips were prepared by inserting these MWCT into fine glass capillary tubes that were pulled at high temperatures and then cut. Measurements were carried out under ultra-high vacuum (UHV) conditions with a base pressure of 10-9 mbar. The data show the effects of initial conditioning of MWCNT and hysteresis. Compression of the MWCNT by the capillary tubes appears to provide adequate mechanical support without requiring the use of a low-melting point electrically-conductive binder as has been used previously. Emission currents in excess of 1 μA were obtained so this technique shows promise as a reliable, stable, powerful electron source.

Mucosal pathology of an experimental otitis media with effusion after X-ray irradiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ohashi, Y.; Nakai, Y.; Ikeoka, H.

1987-07-01

Ten guinea pigs were irradiated with 30 Gy of x-radiation. Five were killed on the eighth day after irradiation, and the remainder were killed at the sixteenth day after irradiation. At the time of death, examination was made of the ciliary activity and the fine structure of the middle ear mucosa. Serous effusion was found in each tympanic cavity of all animals. It was shown also that the guinea pig, when irradiated with 30 Gy of x-radiation, exhibits pathologic abnormalities similar to those in humans with otitis media with effusion: degeneration of cilia or ciliated cells and changes in themore » vascular system (capillary injury and increased capillary permeability). Functional examinations showed that x-ray irradiation has delayed effects on ciliary activity, and the effects are much greater at the sixteenth day than at the eighth day. We speculate that the accumulation of effusion can be, at least partially, a consequence of ciliary dysfunction. The induction of sterile effusion by the use of x-ray irradiation provides a unique animal model for chronic otitis media with effusion of the serous type.« less

Capillary photoelectrode structures for photoelectrochemical and photocatalytic cells

DOEpatents

Wang, Xudong; Li, Zhaodong; Cai, Zhiyong; Yao, Chunhua

2017-05-02

Photocatalytic structures having a capillary-force based electrolyte delivery system are provided. Also provided are photoelectrochemical and photocatalytic cells incorporating the structures and methods for using the cells to generate hydrogen and/or oxygen from water. The photocatalytic structures use an electrolyte-transporting strip comprising a porous network of cellulose nanofibers to transport electrolyte from a body of the electrolyte to a porous photoelectrode or a porous photocatalytic substrate via capillary force.

Fatigue Performance of Ti-6Al-4V Additively Manufactured Specimens with Integrated Capillaries of an Embedded Structural Health Monitoring System

PubMed Central

Hinderdael, Michaël; Strantza, Maria; De Baere, Dieter; Devesse, Wim; De Graeve, Iris; Terryn, Herman; Guillaume, Patrick

2017-01-01

Additive manufacturing (AM) of metals offers new possibilities for the production of complex structures. Up to now, investigations on the mechanical response of AM metallic parts show a significant spread and unexpected failures cannot be excluded. In this work, we focus on the detection of fatigue cracks through the integration of a Structural Health Monitoring (SHM) system in Ti-6Al-4V specimens. The working principle of the presented system is based on the integration of small capillaries that are capable of detecting fatigue cracks. Four-point bending fatigue tests have been performed on Ti-6Al-4V specimens with integrated capillaries and compared to the reference specimenswithout capillaries. Specimens were produced by conventional subtractive manufacturing of wrought material and AM, using the laser based Directed Energy Deposition (DED) process. In this study, we investigated the effect of the presence of the capillary on the fatigue strength and fatigue initiation location. Finite element (FEM) simulations were performed to validate the experimental test results. The presence of a drilled capillary in the specimens did not alter the fatigue initiation location. However, the laser based DED production process introduced roughness on the capillary surface that altered the fatigue initiation location to the capillary surface. The fatigue performance was greatly reduced when considering a printed capillary. It is concluded that the surface quality of the integrated capillary is of primary importance in order not to influence the structural integrity of the component to be monitored. PMID:28841186

Fatigue Performance of Ti-6Al-4V Additively Manufactured Specimens with Integrated Capillaries of an Embedded Structural Health Monitoring System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hinderdael, Michaël; Strantza, Maria; De Baere, Dieter

Additive manufacturing (AM) of metals offers new possibilities for the production of complex structures. Up to now, investigations on the mechanical response of AM metallic parts show a significant spread and unexpected failures cannot be excluded. In this work, we focus on the detection of fatigue cracks through the integration of a Structural Health Monitoring (SHM) system in Ti-6Al-4V specimens. The working principle of the presented system is based on the integration of small capillaries that are capable of detecting fatigue cracks. Four-point bending fatigue tests have been performed on Ti-6Al-4V specimens with integrated capillaries and compared to the referencemore » specimenswithout capillaries. Specimens were produced by conventional subtractive manufacturing of wrought material and AM, using the laser based Directed Energy Deposition (DED) process. In this study, we investigated the effect of the presence of the capillary on the fatigue strength and fatigue initiation location. Finite element (FEM) simulations were performed to validate the experimental test results. The presence of a drilled capillary in the specimens did not alter the fatigue initiation location. However, the laser based DED production process introduced roughness on the capillary surface that altered the fatigue initiation location to the capillary surface. The fatigue performance was greatly reduced when considering a printed capillary. It is concluded that the surface quality of the integrated capillary is of primary importance in order not to influence the structural integrity of the component to be monitored.« less

Fatigue Performance of Ti-6Al-4V Additively Manufactured Specimens with Integrated Capillaries of an Embedded Structural Health Monitoring System

DOE PAGES

Hinderdael, Michaël; Strantza, Maria; De Baere, Dieter; ...

2017-08-25

Additive manufacturing (AM) of metals offers new possibilities for the production of complex structures. Up to now, investigations on the mechanical response of AM metallic parts show a significant spread and unexpected failures cannot be excluded. In this work, we focus on the detection of fatigue cracks through the integration of a Structural Health Monitoring (SHM) system in Ti-6Al-4V specimens. The working principle of the presented system is based on the integration of small capillaries that are capable of detecting fatigue cracks. Four-point bending fatigue tests have been performed on Ti-6Al-4V specimens with integrated capillaries and compared to the referencemore » specimenswithout capillaries. Specimens were produced by conventional subtractive manufacturing of wrought material and AM, using the laser based Directed Energy Deposition (DED) process. In this study, we investigated the effect of the presence of the capillary on the fatigue strength and fatigue initiation location. Finite element (FEM) simulations were performed to validate the experimental test results. The presence of a drilled capillary in the specimens did not alter the fatigue initiation location. However, the laser based DED production process introduced roughness on the capillary surface that altered the fatigue initiation location to the capillary surface. The fatigue performance was greatly reduced when considering a printed capillary. It is concluded that the surface quality of the integrated capillary is of primary importance in order not to influence the structural integrity of the component to be monitored.« less

Fatigue Performance of Ti-6Al-4V Additively Manufactured Specimens with Integrated Capillaries of an Embedded Structural Health Monitoring System.

PubMed

Hinderdael, Michaël; Strantza, Maria; De Baere, Dieter; Devesse, Wim; De Graeve, Iris; Terryn, Herman; Guillaume, Patrick

2017-08-25

Additive manufacturing (AM) of metals offers new possibilities for the production of complex structures. Up to now, investigations on the mechanical response of AM metallic parts show a significant spread and unexpected failures cannot be excluded. In this work, we focus on the detection of fatigue cracks through the integration of a Structural Health Monitoring (SHM) system in Ti-6Al-4V specimens. The working principle of the presented system is based on the integration of small capillaries that are capable of detecting fatigue cracks. Four-point bending fatigue tests have been performed on Ti-6Al-4V specimens with integrated capillaries and compared to the reference specimenswithout capillaries. Specimens were produced by conventional subtractive manufacturing of wrought material and AM, using the laser based Directed Energy Deposition (DED) process. In this study, we investigated the effect of the presence of the capillary on the fatigue strength and fatigue initiation location. Finite element (FEM) simulations were performed to validate the experimental test results. The presence of a drilled capillary in the specimens did not alter the fatigue initiation location. However, the laser based DED production process introduced roughness on the capillary surface that altered the fatigue initiation location to the capillary surface. The fatigue performance was greatly reduced when considering a printed capillary. It is concluded that the surface quality of the integrated capillary is of primary importance in order not to influence the structural integrity of the component to be monitored.

A novel method of creation capillary structures in metal parts based on using selective laser melting methid of 3D printing technology and surface roughness

NASA Astrophysics Data System (ADS)

Ivanov, Roman A.; Melkikh, Alexey V.

2017-09-01

It has been experimentally proved that it is possible to produce a metal capillary structure with significant capillary action and free shape configuration using selective laser melting. Capillaries are created by dividing the solid detail volume into micro-sized parallel walls with roughness as a result of SLM 3D printing. Experiments are conducted on aluminum powder with particle size in the range of 10-40 µm (,) and distances in 3D model between surfaces incapillary generation zone in the range of 50-200 µm. It is showed that products produced from model with 100 µm gaps have the greatest efficiency of fluid lifting as a result of obtaining stable arrays of capillaries of 20-40 µm in size. Change in the direction of (growing) printingthe product doesn't significantly influence on capillary geometry, but it affects on safety of the structure.

Increased Durability of Concrete Made with Fine Recycled Concrete Aggregates Using Superplasticizers

PubMed Central

Cartuxo, Francisco; de Brito, Jorge; Evangelista, Luis; Jiménez, José Ramón; Ledesma, Enrique F.

2016-01-01

This paper evaluates the influence of two superplasticizers (SP) on the durability properties of concrete made with fine recycled concrete aggregate (FRCA). For this purpose, three families of concrete were tested: concrete without SP, concrete made with a regular superplasticizer and concrete made with a high-performance superplasticizer. Five volumetric replacement ratios of natural sand by FRCA were tested: 0%, 10%, 30%, 50% and 100%. Two natural gravels were used as coarse aggregates. All mixes had the same particle size distribution, cement content and amount of superplasticizer. The w/c ratio was calibrated to obtain similar slump. The results showed that the incorporation of FRCA increased the water absorption by immersion, the water absorption by capillary action, the carbonation depth and the chloride migration coefficient, while the use of superplasticizers highly improved these properties. The incorporation of FRCA jeopardized the SP’s effectiveness. This research demonstrated that, from a durability point of view, the simultaneous incorporation of FRCA and high-performance SP is a viable sustainable solution for structural concrete production. PMID:28787905

Tuning and Freezing Disorder in Photonic Crystals using Percolation Lithography

PubMed Central

Burgess, Ian B.; Abedzadeh, Navid; Kay, Theresa M.; Shneidman, Anna V.; Cranshaw, Derek J.; Lončar, Marko; Aizenberg, Joanna

2016-01-01

Although common in biological systems, synthetic self-assembly routes to complex 3D photonic structures with tailored degrees of disorder remain elusive. Here we show how liquids can be used to finely control disorder in porous 3D photonic crystals, leading to complex and hierarchical geometries. In these optofluidic crystals, dynamically tunable disorder is superimposed onto the periodic optical structure through partial wetting or evaporation. In both cases, macroscopic symmetry breaking is driven by subtle sub-wavelength variations in the pore geometry. These variations direct site-selective infiltration of liquids through capillary interactions. Incorporating cross-linkable resins into our liquids, we developed methods to freeze in place the filling patterns at arbitrary degrees of partial wetting and intermediate stages of drying. These percolation lithography techniques produced permanent photonic structures with adjustable disorder. By coupling strong changes in optical properties to subtle differences in fluid behavior, optofluidic crystals may also prove useful in rapid analysis of liquids. PMID:26790372

A lattice Boltzmann investigation of steady-state fluid distribution, capillary pressure and relative permeability of a porous medium: Effects of fluid and geometrical properties

NASA Astrophysics Data System (ADS)

Li, Zi; Galindo-Torres, Sergio; Yan, Guanxi; Scheuermann, Alexander; Li, Ling

2018-06-01

Simulations of simultaneous steady-state two-phase flow in the capillary force-dominated regime were conducted using the state-of-the-art Shan-Chen multi-component lattice Boltzmann model (SCMC-LBM) based on two-dimensional porous media. We focused on analyzing the fluid distribution (i.e., WP fluid-solid, NP fluid-solid and fluid-fluid interfacial areas) as well as the capillary pressure versus saturation curve which was affected by fluid and geometrical properties (i.e., wettability, adhesive strength, pore size distribution and specific surface area). How these properties influenced the relative permeability versus saturation relation through apparent effective permeability and threshold pressure gradient was also explored. The SCMC-LBM simulations showed that, a thin WP fluid film formed around the solid surface due to the adhesive fluid-solid interaction, resulting in discrete WP fluid distributions and reduction of the WP fluid mobility. Also, the adhesive interaction provided another source of capillary pressure in addition to capillary force, which, however, did not affect the mobility of the NP fluid. The film fluid effect could be enhanced by large adhesive strength and fine pores in heterogeneous porous media. In the steady-state infiltration, not only the NP fluid but also the WP fluid were subjected to the capillary resistance. The capillary pressure effect could be alleviated by decreased wettability, large average pore radius and improved fluid connectivity in heterogeneous porous media. The present work based on the SCMC-LBM investigations elucidated the role of film fluid as well as capillary pressure in the two-phase flow system. The findings have implications for ways to improve the macroscopic flow equation based on balance of force for the steady-state infiltration.

Visualization and quantification of capillary drainage in the pore space of laminated sandstone by a porous plate method using differential imaging X-ray microtomography

NASA Astrophysics Data System (ADS)

Lin, Qingyang; Bijeljic, Branko; Rieke, Holger; Blunt, Martin J.

2017-08-01

The experimental determination of capillary pressure drainage curves at the pore scale is of vital importance for the mapping of reservoir fluid distribution. To fully characterize capillary drainage in a complex pore space, we design a differential imaging-based porous plate (DIPP) method using X-ray microtomography. For an exemplar mm-scale laminated sandstone microcore with a porous plate, we quantify the displacement from resolvable macropores and subresolution micropores. Nitrogen (N2) was injected as the nonwetting phase at a constant pressure while the porous plate prevented its escape. The measured porosity and capillary pressure at the imaged saturations agree well with helium measurements and experiments on larger core samples, while providing a pore-scale explanation of the fluid distribution. We observed that the majority of the brine was displaced by N2 in macropores at low capillary pressures, followed by a further brine displacement in micropores when capillary pressure increases. Furthermore, we were able to discern that brine predominantly remained within the subresolution micropores, such as regions of fine lamination. The capillary pressure curve for pressures ranging from 0 to 1151 kPa is provided from the image analysis compares well with the conventional porous plate method for a cm-scale core but was conducted over a period of 10 days rather than up to few months with the conventional porous plate method. Overall, we demonstrate the capability of our method to provide quantitative information on two-phase saturation in heterogeneous core samples for a wide range of capillary pressures even at scales smaller than the micro-CT resolution.

Interplay between shape and roughness in early-stage microcapillary imbibition.

PubMed

Girardo, Salvatore; Palpacelli, Silvia; De Maio, Alessandro; Cingolani, Roberto; Succi, Sauro; Pisignano, Dario

2012-02-07

Flows in microcapillaries and associated imbibition phenomena play a major role across a wide spectrum of practical applications, from oil recovery to inkjet printing and from absorption in porous materials and water transport in trees to biofluidic phenomena in biomedical devices. Early investigations of spontaneous imbibition in capillaries led to the observation of a universal scaling behavior, known as the Lucas-Washburn (LW) law. The LW allows abstraction of many real-life effects, such as the inertia of the fluid, irregularities in the wall geometry, and the finite density of the vacuum phase (gas or vapor) within the channel. Such simplifying assumptions set a constraint on the design of modern microfluidic devices, operating at ever-decreasing space and time scales, where the aforementioned simplifications go under serious question. Here, through a combined use of leading-edge experimental and simulation techniques, we unravel a novel interplay between global shape and nanoscopic roughness. This interplay significantly affects the early-stage energy budget, controlling front propagation in corrugated microchannels. We find that such a budget is governed by a two-scale phenomenon: The global geometry sets the conditions for small-scale structures to develop and propagate ahead of the main front. These small-scale structures probe the fine-scale details of the wall geometry (nanocorrugations), and the additional friction they experience slows the entire front. We speculate that such a two-scale mechanism may provide a fairly general scenario to account for extra dissipative phenomena occurring in capillary flows with nanocorrugated walls.

Measurement of Capillary Radius and Contact Angle within Porous Media.

PubMed

Ravi, Saitej; Dharmarajan, Ramanathan; Moghaddam, Saeed

2015-12-01

The pore radius (i.e., capillary radius) and contact angle determine the capillary pressure generated in a porous medium. The most common method to determine these two parameters is through measurement of the capillary pressure generated by a reference liquid (i.e., a liquid with near-zero contact angle) and a test liquid. The rate of rise technique, commonly used to determine the capillary pressure, results in significant uncertainties. In this study, we utilize a recently developed technique for independently measuring the capillary pressure and permeability to determine the equivalent minimum capillary radii and contact angle of water within micropillar wick structures. In this method, the experimentally measured dryout threshold of a wick structure at different wicking lengths is fit to Darcy's law to extract the maximum capillary pressure generated by the test liquid. The equivalent minimum capillary radii of different wick geometries are determined by measuring the maximum capillary pressures generated using n-hexane as the working fluid. It is found that the equivalent minimum capillary radius is dependent on the diameter of pillars and the spacing between pillars. The equivalent capillary radii of micropillar wicks determined using the new method are found to be up to 7 times greater than the current geometry-based first-order estimates. The contact angle subtended by water at the walls of the micropillars is determined by measuring the capillary pressure generated by water within the arrays and the measured capillary radii for the different geometries. This mean contact angle of water is determined to be 54.7°.

Continuous micro-feeding of fine cohesive powders actuated by pulse inertia force and acoustic radiation force in ultrasonic standing wave field.

PubMed

Wang, Hongcheng; Wu, Liqun; Zhang, Ting; Chen, Rangrang; Zhang, Linan

2018-07-10

Stable continuous micro-feeding of fine cohesive powders has recently gained importance in many fields. However, it remains a great challenge in practice because of the powder aggregate caused by interparticle cohesive forces in small capillaries. This paper describes a novel method of feeding fine cohesive powder actuated by a pulse inertia force and acoustic radiation force simultaneously in an ultrasonic standing wave field using a tapered glass nozzle. Nozzles with different outlet diameters are fabricated using glass via a heating process. A pulse inertia force is excited to drive powder movement to the outlet section of the nozzle in a consolidated columnar rod mode. An acoustic radiation force is generated to suspend the particles and make the rod break into large quantities of small agglomerates which impact each other randomly. So the aggregation phenomenon in the fluidization of cohesive powders can be eliminated. The suspended powder is discharged continuously from the nozzle orifice owing to the self-gravities and collisions between the inner particles. The micro-feeding rates can be controlled accurately and the minimum values for RespitoseSV003 and Granulac230 are 0.4 mg/s and 0.5 mg/s respectively. The relative standard deviations of all data points are below 0.12, which is considerably smaller than those of existing vibration feeders with small capillaries. Copyright © 2018 Elsevier B.V. All rights reserved.

Contribution of hydraulically lifted deep moisture to the water budget in a Southern California mixed forest

NASA Astrophysics Data System (ADS)

Kitajima, Kuni; Allen, Michael F.; Goulden, Michael L.

2013-12-01

and shrubs growing in California's mountains rely on deep roots to survive the hot and dry Mediterranean climate summer. The shallow montane soil cannot hold enough water to support summer transpiration, and plants must access deeper moisture from the weathered bedrock. We used the HYDRUS-1D model to simulate the moisture flux through the soil-plant continuum in Southern California's San Jacinto Mountains. The mechanisms facilitating deep water access are poorly understood, and it is possible that either or both hydraulic lift and capillary rise contribute to the survival and activity of trees and soil microorganisms. We modified HYDRUS to incorporate hydraulic lift and drove it with meteorological and physiological data. The modeled quantity of water lifted hydraulically ranged from near zero during the wet months to ~28 mm month-1 in midsummer. Likewise, modeled capillary rise was negligible during the winter and averaged ~15 mm month-1 during June through November. Both mechanisms provided water to support evapotranspiration during the dry months. Isotopic measurements of xylem water for eight shrub and tree species confirmed the importance of a deep source of water. Conventional and automated minirhizotron observations showed that fine-root and rhizomorph biomass remained relatively constant year-round, while mycorrhizal hyphae biomass varied markedly, peaking in the wet season and declining by ~70% in the dry season. Model results predict that hydraulic lift and capillary rise play key roles in Southern California's mountains: they support evapotranspiration and photosynthesis during the summer drought; they contribute to the year-round survival of fine roots and soil microorganisms.

Fine structure of the transitional zone of the rat seminiferous tubule.

PubMed

Nykänen, M

1979-05-25

An electron microscopic study was made on the structure of the testicular transitional zone (TZ) in the adult rat. The TZ proper consists of modified Sertoli cellss, with only a few spermatogonia and macrophages, surrounding distally a very narrow lumen. The TZ Sertoli cells have nuclei with a somewhat coarser matrix and more peripheral heterochromatin than Sertoli cell nuclei of the nearby seminiferous tubules, and the electron density of the cytoplasm varies from cell to cell. Smooth endoplasmic reticulum is abundant, but usually there are also scattered ribosomal rosettes and an occasional profile of rough endoplasmic reticulum. Microtubules are very numerous in the columnar portion of the cell, and laminar structures seemingly joining the cell surfaces are sometimes seen. Lipid droplets and lysosmal structures are frequent cellular components in proximal TZ Sertoli cells. Empty intracellular vacuoles are abundant, sometimes arranged around areas of smooth endoplasmic reticulum. Occasionally, membrane-limited fine granules and vacuoles are seen within Sertoli cells and also in the TZ lumen, suggesting a possible secretory activity by these cells. The apical processes of the Sertoli cells form large vacuolar structures, and in the basal parts of the epithelium vacuoles with capillary-like appearance are frequently seen. Phagocytosis of germinal cells by the Sertoli cells occurs in the proximal region of the TZ. Round waste bodies in contact with the Sertoli cell apices protruding into the tubulus rectus, are also common. The tunica propria of the TZ is thickened and somewhat wrinkled, and in the proximal region the myoid cell layer loses its continuity and is replaced by fibroblasts. The epithelium of the tubulus rectus adjacent to the TZ consists of several overlapping epithelial cells. The typical junctional complexes between TZ Sertoli cells appear to be impermeable to the lanthanum tracer.

Computer-aided design of microvasculature systems for use in vascular scaffold production.

PubMed

Mondy, William Lafayette; Cameron, Don; Timmermans, Jean-Pierre; De Clerck, Nora; Sasov, Alexander; Casteleyn, Christophe; Piegl, Les A

2009-09-01

In vitro biomedical engineering of intact, functional vascular networks, which include capillary structures, is a prerequisite for adequate vascular scaffold production. Capillary structures are necessary since they provide the elements and compounds for the growth, function and maintenance of 3D tissue structures. Computer-aided modeling of stereolithographic (STL) micro-computer tomographic (micro-CT) 3D models is a technique that enables us to mimic the design of vascular tree systems containing capillary beds, found in tissues. In our first paper (Mondy et al 2009 Tissue Eng. at press), using micro-CT, we studied the possibility of using vascular tissues to produce data capable of aiding the design of vascular tree scaffolding, which would help in the reverse engineering of a complete vascular tree system including capillary bed structures. In this paper, we used STL models of large datasets of computer-aided design (CAD) data of vascular structures which contained capillary structures that mimic those in the dermal layers of rabbit skin. Using CAD software we created from 3D STL models a bio-CAD design for the development of capillary-containing vascular tree scaffolding for skin. This method is designed to enhance a variety of therapeutic protocols including, but not limited to, organ and tissue repair, systemic disease mediation and cell/tissue transplantation therapy. Our successful approach to in vitro vasculogenesis will allow the bioengineering of various other types of 3D tissue structures, and as such greatly expands the potential applications of biomedical engineering technology into the fields of biomedical research and medicine.

Hemangiopericytoma in a male breast. Report of a case with cytologic, histologic and immunochemical studies.

PubMed

Jiménez-Ayala, M; Díez-Nau, M D; Larrad, A; Ferrer-Vergara, L; Rodriguez-Costa, J; Lacruz, C; Escalona-Zapata, J

1991-01-01

A hemangiopericytoma in a male breast was studied by fine needle aspiration (FNA) biopsy. The FNA smears contained tissue clumps showing knob-like formations of atypical cells, spindle-shaped cells and fragments of capillaries lined by normal endothelial cells. Immunocytochemical study showed a positive reaction for vimentin, but a negative reaction for desmin and keratin. Staining for Factor VIII was positive only in the capillaries and endothelial cells. The cytodiagnosis was "mesenchymal tumor." Histopathologic study of the mastectomy specimen made the final diagnosis of hemangiopericytoma. While FNA cytology and immunocytochemistry cannot make a definitive diagnosis of this rare vascular tumor, they can be decisive in planning the surgical treatment, as in the present case.

Effect of anti-vertigo granule on the opening number and blood flow of mouse ear capillary network

NASA Astrophysics Data System (ADS)

Li, Chongxian; Liu, Xiaobin; Li, Jun; Hao, Shaojun; Wang, Xidong; Li, Wenjun; Zhang, Zhengchen

2018-04-01

To observe the effects of anti-glare particles on the open number and blood flow in the auricle of mice with microcirculation disturbance model. Sixty mice, half male and half female, were randomly divided into 6 groups. The mice were given Kangxuan granule suspension, serum brain granule suspension and normal saline of the same volume, respectively, once a day. The mice were anesthetized by intraperitoneal injection of chloral hydrate at 1 hour after the last administration. The mouse was fixed on the observation platform and the auricle was placed on the transmission stage. BZ-2000 microcirculation microscope and microcirculation analysis system were used to observe the changes of blood velocity and capillary opening volume in auricle of mice before administration. The changes of blood velocity and capillaries opening volume of mouse auricle were observed 2 min after epinephrine injection into tail vein of mice. Bear fruit: Compared with those before epinephrine, the opening number of capillary reticulum of auricle in large dose Kangxuan granule group was significantly decreased (P<0.05), and in normal saline group and middle group. In the small dose Kangxuan granule group, the opening number of capillary network of auricle decreased significantly (P<0.01). Compared with the model group, the large dose Kangxuan granule group could significantly increase the opening number of the auricle capillary network in mice (P<0.01). Yangxuannao granule group could significantly increase the opening number of auricle capillary reticulum in mice (P<0.05), compared with the model group by Ridit test. Both Kangxuan granule group and Yangxuannao granule group could significantly improve the auricle hair of mice with microcirculation disorder. The blood flow in fine blood vessels (P<0.01). Kangxuan granule has a good effect on the opening number of capillary network of auricle and blood flow in mice with microcirculation disorder.

Fine pitch thermosonic wire bonding: analysis of state-of-the-art manufacturing capability

NASA Astrophysics Data System (ADS)

Cavasin, Daniel

1995-09-01

A comprehensive process characterization was performed at the Motorola plastic package assembly site in Selangor, Malaysia, to document the current fine pitch wire bond process capability, using state-of-the-art equipment, in an actual manufacturing environment. Two machines, representing the latest technology from two separate manufacturers, were operated one shift per day for five days, bonding a 132 lead Plastic Quad Flat Pack. Using a test device specifically designed for fine pitch wire bonding, the bonding programs were alternated between 107 micrometers and 92 micrometers pad pitch, running each pitch for a total of 1600 units per machine. Wire, capillary type, and related materials were standardized and commercially available. A video metrology measurement system, with a demonstrated six sigma repeatability band width of 0.51 micrometers , was utilized to measure the bonded units for bond dimensions and placement. Standard Quality Assurance (QA) metrics were also performed. Results indicate that state-of-the-art thermosonic wire bonding can achieve acceptable assembly yields at these fine pad pitches.

Using laser radiation for the formation of capillary structure in flat ceramic heat pipes

NASA Astrophysics Data System (ADS)

Nikolaenko, Yu. E.; Rotner, S. M.

2012-12-01

The possibility of using laser radiation with a wavelength of 1.064 μm for the formation of a capillary structure in the evaporation zone of flat ceramic heat pipes has been experimentally confirmed. Using a technological regime with established parameters, a capillary structure was formed in AlN and Al2O3 ceramic plates with a thickness of 1-2 mm and lateral dimensions of 48 × 60 and 100 × 100 mm, which ensured absorption of heat-transfer fluids (distilled water, ethyl alcohol, acetone) to a height of 100 mm against gravity forces. The thermal resistance of flat ceramic heat pipes with this capillary structure reaches 0.07°C/W, which is quite acceptable for their use as heat sinks in systems of thermal regime control for electronic components and as heat exchange plates for large-size thermoelectric conversion units.

Capillary condenser/evaporator

NASA Technical Reports Server (NTRS)

Valenzuela, Javier A. (Inventor)

2010-01-01

A heat transfer device is disclosed for transferring heat to or from a fluid that is undergoing a phase change. The heat transfer device includes a liquid-vapor manifold in fluid communication with a capillary structure thermally connected to a heat transfer interface, all of which are disposed in a housing to contain the vapor. The liquid-vapor manifold transports liquid in a first direction and conducts vapor in a second, opposite direction. The manifold provides a distributed supply of fluid (vapor or liquid) over the surface of the capillary structure. In one embodiment, the manifold has a fractal structure including one or more layers, each layer having one or more conduits for transporting liquid and one or more openings for conducting vapor. Adjacent layers have an increasing number of openings with decreasing area, and an increasing number of conduits with decreasing cross-sectional area, moving in a direction toward the capillary structure.

In vivo multiphoton imaging of a diverse array of fluorophores to investigate deep neurovascular structure

PubMed Central

Miller, David R.; Hassan, Ahmed M.; Jarrett, Jeremy W.; Medina, Flor A.; Perillo, Evan P.; Hagan, Kristen; Shams Kazmi, S. M.; Clark, Taylor A.; Sullender, Colin T.; Jones, Theresa A.; Zemelman, Boris V.; Dunn, Andrew K.

2017-01-01

We perform high-resolution, non-invasive, in vivo deep-tissue imaging of the mouse neocortex using multiphoton microscopy with a high repetition rate optical parametric amplifier laser source tunable between λ=1,100 and 1,400 nm. By combining the high repetition rate (511 kHz) and high pulse energy (400 nJ) of our amplifier laser system, we demonstrate imaging of vasculature labeled with Texas Red and Indocyanine Green, and neurons expressing tdTomato and yellow fluorescent protein. We measure the blood flow speed of a single capillary at a depth of 1.2 mm, and image vasculature to a depth of 1.53 mm with fine axial steps (5 μm) and reasonable acquisition times. The high image quality enabled analysis of vascular morphology at depths to 1.45 mm. PMID:28717582

CXC Chemokine Receptor 7 (CXCR7) Regulates CXCR4 Protein Expression and Capillary Tuft Development in Mouse Kidney

PubMed Central

Haege, Sammy; Mueller, Wiebke; Nietzsche, Sandor; Lupp, Amelie; Mackay, Fabienne; Schulz, Stefan; Stumm, Ralf

2012-01-01

Background The CXCL12/CXCR4 axis is involved in kidney development by regulating formation of the glomerular tuft. Recently, a second CXCL12 receptor was identified and designated CXCR7. Although it is established that CXCR7 regulates heart and brain development in conjunction with CXCL12 and CXCR4, little is known about the influence of CXCR7 on CXCL12 dependent kidney development. Methodology/Principal Findings We provided analysis of CXCR7 expression and function in the developing mouse kidney. Using in situ hybridization, we identified CXCR7 mRNA in epithelial cells including podocytes at all nephron stages up to the mature glomerulus. CXCL12 mRNA showed a striking overlap with CXCR7 mRNA in epithelial structures. In addition, CXCL12 was detected in stromal cells and the glomerular tuft. Expression of CXCR4 was complementary to that of CXCR7 as it occurred in mesenchymal cells, outgrowing ureteric buds and glomerular endothelial cells but not in podocytes. Kidney examination in CXCR7 null mice revealed ballooning of glomerular capillaries as described earlier for CXCR4 null mice. Moreover, we detected a severe reduction of CXCR4 protein but not CXCR4 mRNA within the glomerular tuft and in the condensed mesenchyme. Malformation of the glomerular tuft in CXCR7 null mice was associated with mesangial cell clumping. Conclusions/Significance We established that there is a similar glomerular pathology in CXCR7 and CXCR4 null embryos. Based on the phenotype and the anatomical organization of the CXCL12/CXCR4/CXCR7 system in the forming glomerulus, we propose that CXCR7 fine-tunes CXCL12/CXCR4 mediated signalling between podocytes and glomerular capillaries. PMID:22880115

CXC chemokine receptor 7 (CXCR7) regulates CXCR4 protein expression and capillary tuft development in mouse kidney.

PubMed

Haege, Sammy; Einer, Claudia; Thiele, Stefanie; Mueller, Wiebke; Nietzsche, Sandor; Lupp, Amelie; Mackay, Fabienne; Schulz, Stefan; Stumm, Ralf

2012-01-01

The CXCL12/CXCR4 axis is involved in kidney development by regulating formation of the glomerular tuft. Recently, a second CXCL12 receptor was identified and designated CXCR7. Although it is established that CXCR7 regulates heart and brain development in conjunction with CXCL12 and CXCR4, little is known about the influence of CXCR7 on CXCL12 dependent kidney development. We provided analysis of CXCR7 expression and function in the developing mouse kidney. Using in situ hybridization, we identified CXCR7 mRNA in epithelial cells including podocytes at all nephron stages up to the mature glomerulus. CXCL12 mRNA showed a striking overlap with CXCR7 mRNA in epithelial structures. In addition, CXCL12 was detected in stromal cells and the glomerular tuft. Expression of CXCR4 was complementary to that of CXCR7 as it occurred in mesenchymal cells, outgrowing ureteric buds and glomerular endothelial cells but not in podocytes. Kidney examination in CXCR7 null mice revealed ballooning of glomerular capillaries as described earlier for CXCR4 null mice. Moreover, we detected a severe reduction of CXCR4 protein but not CXCR4 mRNA within the glomerular tuft and in the condensed mesenchyme. Malformation of the glomerular tuft in CXCR7 null mice was associated with mesangial cell clumping. We established that there is a similar glomerular pathology in CXCR7 and CXCR4 null embryos. Based on the phenotype and the anatomical organization of the CXCL12/CXCR4/CXCR7 system in the forming glomerulus, we propose that CXCR7 fine-tunes CXCL12/CXCR4 mediated signalling between podocytes and glomerular capillaries.

Driver-witness electron beam acceleration in dielectric mm-scale capillaries

NASA Astrophysics Data System (ADS)

Lekomtsev, K.; Aryshev, A.; Tishchenko, A. A.; Shevelev, M.; Lyapin, A.; Boogert, S.; Karataev, P.; Terunuma, N.; Urakawa, J.

2018-05-01

We investigated a corrugated mm-scale capillary as a compact accelerating structure in the driver-witness acceleration scheme, and suggested a methodology to measure the acceleration of the witness bunch. The accelerating fields produced by the driver bunch and the energy spread of the witness bunch in a corrugated capillary and in a capillary with a constant inner radius were measured and simulated for both on-axis and off-axis beam propagation. Our simulations predicted a change in the accelerating field structure for the corrugated capillary. Also, an approximately twofold increase of the witness bunch energy gain on the first accelerating cycle was expected for both capillaries for the off-axis beam propagation. These results were confirmed in the experiment, and the maximum measured acceleration of 170 keV /m at 20 pC driver beam charge was achieved for off-axis beam propagation. The driver bunch showed an increase in energy spread of up to 11%, depending on the capillary geometry and beam propagation, with a suppression of the longitudinal energy spread in the witness bunch of up to 15%.

Extrusion and rheology of fine particulate ceramic pastes

NASA Astrophysics Data System (ADS)

Mazzeo, Fred Anthony

A rheological study was conducted on an extruded blend of two alumina powders, Alcoa A-3500-SG and Reynolds ERC. These extruded blends were mixed in four compositions, varying in distribution modulus. This work focuses on the interaction of the composition components, mainly particle size distribution and amount of water at a constant binder amount. The rheological parameters of extruded pastes, Sigma, Tau, alpha and beta, were determined by using capillary rheometry modeling by the methodology set forth by Benbow and Bridgwater. This methodology makes use of capillary rheometer to determine extrusion parameters, which describe the flow behavior of a paste. The parameter values are indirectly determined by extrapolating high shear rate information obtained by the extrusion process. A goal of this research was to determine fundamental rheological properties directly from fundamental rheological equations of state. This was accomplished by assessing the material properties by using a dynamic stress rheometer. The rheological parameters used in this study to characterize the paste are elastic modulus, viscosity, tan delta, and relaxation time. This technique approaches a step closer in understanding the microstructural influence on flow behavior of a paste. This method directly determines rheological properties by using linear viscoelastic theory, giving a quantitative analysis of material properties. A strong correlation between the elastic modulus and sigma, and viscosity and alpha is shown to exist, indicating a relationship between these two techniques. Predictive process control methodology, based on particle packing modeling, quantitatively determined structural parameters useful in evaluating a composition. The determined parameters are: distribution modulus, interparticle separation distance, porosity, and particle crowding index, which are important to understand the extrudates packed state. A connection between the physical structure of the extrudate and its rheological behavior, can lead to a better understanding of what conditions and parameters are necessary to characterize the extrusion process. This study shows how particle packing and particle size influences the rheological behavior of the paste. Results showed that an optimally packed system was found to occur at a distribution modulus of 0.51. This system was determined both experimentally and quantitatively to exhibit the lowest porosity at any water content. The 0.51 system required a lower amount of water to extrude and the parameters of both rheological techniques agreed well, in which all parameters are influenced by the packing state of the paste, and a consistent trend was generally found. The capillary rheometry results can be explained by the strong interaction of particles that occurs at high shear rates. The dynamic stress rheometer results can be explained by the particle packing characteristics, interparticle separation distance and particle-crowding index, and the capillary forces between particles. The excess amount of liquid that is present in the structure decreases the role of the capillary attraction between particles and an increase in the particle size role on the rheological behavior of the pastes occurs.

Simple luminescence detectors using a light-emitting diode or a Xe lamp, optical fiber and charge-coupled device, or photomultiplier for determining proteins in capillary electrophoresis: a critical comparison.

PubMed

Casado-Terrones, Silvia; Fernández-Sánchez, Jorge F; Segura-Carretero, Antonio; Fernández-Gutiérrez, Alberto

2007-06-01

The performance of two homemade fluorescence-induced capillary electrophoresis detectors, one based on light-emitting diode (LED) as the excitation source and a charge-coupled device (CCD) photodetector and the other based on a commercial luminescence spectrometer (Xe lamp) as the excitation source and a photomultiplier tube as a detector, were compared for the determination of fluorescent proteins R-phycoerythrin and B-phycoerythrin. Both devices use commercially available, reasonably priced optical components that can be used by nonexperts. After fine optimization of several optical and separation parameters in both devices, a zone capillary electrophoresis methodology was achieved with 50mM borate buffer (pH 8.4) and 10mM phytic acid for the determination of two phycobiliproteins. Detection limits of 0.50 and 0.64microg/ml for R-phycoerythrin and B-phycoerythrin, respectively, were achieved by using the LED-induced fluorescence capillary electrophoresis (LED-IF-CE) system, and corresponding detection limits of 2.73 and 2.16microg/ml were achieved by using the Xe lamp-IF-CE system. Analytical performance and other parameters, such as cost and potential to miniaturization, are compared for both devices.

Steam and air co-injection in removing residual TCE in unsaturated layered sandy porous media.

PubMed

Peng, Sheng; Wang, Ning; Chen, Jiajun

2013-10-01

Steam and air co-injection is a promising technique for volatile and semi-volatile organic contaminant remediation in heterogeneous porous media. In this study, removal of trichloroethene (TCE) with steam-air co-injection was investigated through a series of 2D sandbox experiments with different layered sand structures, and through numerical simulations. The results show that a layered structure with coarse sand, in which steam and air convection are relatively rapid, resulted in a higher removal rate and a larger removal ratio than those observed in an experiment using finer sand; however, the difference was not significant, and the removal ratios from three experiments ranged from 85% to 94%. Slight downward movement of TCE was observed for Experiment 1 (TCE initially in a fine sand zone encased in a coarse sand), while no such movement was observed for Experiment 2 (TCE initially in two fine sand layers encased in a coarse sand) or 3 (TCE initially in a silty sand zone encased in a coarse sand). Simulations show accumulation of TCE at the interface of the layered sands, which indicates a capillary barrier effect in restraining the downward movement of TCE. This effect is illustrated further by a numerical experiment with homogeneous coarse sand, in which continuous downward TCE movement to the bottom of the sandbox was simulated. Another numerical experiment with higher water saturation was also conducted. The results illustrate a complicated influence of water saturation on TCE removal in a layered sand structure. Published by Elsevier B.V.

Heat pipe with embedded wick structure

DOEpatents

Adkins, Douglas Ray; Shen, David S.; Tuck, Melanie R.; Palmer, David W.; Grafe, V. Gerald

1998-01-01

A heat pipe has an embedded wick structure that maximizes capillary pumping capability. Heat from attached devices such as integrated circuits evaporates working fluid in the heat pipe. The vapor cools and condenses on a heat dissipation surface. The condensate collects in the wick structure, where capillary pumping returns the fluid to high heat areas.

Heat pipe with embedded wick structure

DOEpatents

Adkins, D.R.; Shen, D.S.; Tuck, M.R.; Palmer, D.W.; Grafe, V.G.

1998-06-23

A heat pipe has an embedded wick structure that maximizes capillary pumping capability. Heat from attached devices such as integrated circuits evaporates working fluid in the heat pipe. The vapor cools and condenses on a heat dissipation surface. The condensate collects in the wick structure, where capillary pumping returns the fluid to high heat areas. 7 figs.

Heat pipe with embedded wick structure

DOEpatents

Adkins, Douglas Ray; Shen, David S.; Tuck, Melanie R.; Palmer, David W.; Grafe, V. Gerald

1999-01-01

A heat pipe has an embedded wick structure that maximizes capillary pumping capability. Heat from attached devices such as integrated circuits evaporates working fluid in the heat pipe. The vapor cools and condenses on a heat dissipation surface. The condensate collects in the wick structure, where capillary pumping returns the fluid to high heat areas.

Evaporation on/in Capillary Structures of High Heat Flux Two-Phase Devices

NASA Technical Reports Server (NTRS)

Faghri, Amir; Khrustalev, Dmitry

1996-01-01

Two-phase devices (heat pipes, capillary pumped loops, loop heat pipes, and evaporators) have become recognized as key elements in thermal control systems of space platforms. Capillary and porous structures are necessary and widely used in these devices, especially in high heat flux and zero-g applications, to provide fluid transport and enhanced heat transfer during vaporization and condensation. However, some unexpected critical phenomena, such as dryout in long heat pipe evaporators and high thermal resistance of loop heat pipe evaporators with high heat fluxes, are possible and have been encountered in the use of two-phase devices in the low gravity environment. Therefore, a detailed fundamental investigation is proposed to better understand the fluid behavior in capillary-porous structures during vaporization at high heat fluxes. The present paper addresses some theoretical aspects of this investigation.

Influence of local capillary trapping on containment system effectiveness

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bryant, Steven

2014-03-31

Immobilization of CO 2 injected into deep subsurface storage reservoirs is a critical component of risk assessment for geologic CO 2 storage (GCS). Local capillary trapping (LCT) is a recently established mode of immobilization that arises when CO 2 migrates due to buoyancy through heterogeneous storage reservoirs. This project sought to assess the amount and extent of LCT expected in storage formations under a range of injection conditions, and to confirm the persistence of LCT if the seal overlying the reservoir were to lose its integrity. Numerical simulation using commercial reservoir simulation software was conducted to assess the influence ofmore » injection. Laboratory experiments, modeling and numerical simulation were conducted to assess the effect of compromised seal integrity. Bench-scale (0.6 m by 0.6 m by 0.03 m) experiments with surrogate fluids provided the first empirical confirmation of the key concepts underlying LCT: accumulation of buoyant nonwetting phase at above residual saturations beneath capillary barriers in a variety of structures, which remains immobile under normal capillary pressure gradients. Immobilization of above-residual saturations is a critical distinction between LCT and the more familiar “residual saturation trapping.” To estimate the possible extent of LCT in a storage reservoir an algorithm was developed to identify all potential local traps, given the spatial distribution of capillary entry pressure in the reservoir. The algorithm assumes that the driving force for CO 2 migration can be represented as a single value of “critical capillary entry pressure” P c,entry crit, such that cells with capillary entry pressure greater/less than P c,entry crit act as barriers/potential traps during CO 2 migration. At intermediate values of P c,entry crit, the barrier regions become more laterally extensive in the reservoir, approaching a percolation threshold while non-barrier regions remain numerous. The maximum possible extent of LCT thus occurs at P c,entry crit near this threshold. Testing predictions of this simple algorithm against full-physics simulations of buoyancy-driven CO 2 migration support the concept of critical capillary entry pressure. However, further research is needed to determine whether a single value of critical capillary entry pressure always applies and how that value can be determined a priori. Simulations of injection into high-resolution (cells 0.3 m on a side) 2D and 3D heterogeneous domains show two characteristic behaviors. At small gravity numbers (vertical flow velocity much less than horizontal flow velocity) the CO 2 fills local traps as well as regions that would act as local barriers if CO 2 were moving only due to buoyancy. When injection ceases, the CO 2 migrates vertically to establish large saturations within local traps and residual saturation elsewhere. At large gravity numbers, the CO 2 invades a smaller portion of the perforated interval. Within this smaller swept zone the local barriers are not invaded, but local traps are filled to large saturation during injection and remain during post-injection gravity-driven migration. The small gravity number behavior is expected in the region within 100 m of a vertical injection well at anticipated rates of injection for commercial GCS. Simulations of leakage scenarios (through-going region of large permeability imposed in overlying seal) indicate that LCT persists (i.e. CO 2 remains held in a large fraction of the local iv traps) and the persistence is independent of injection rate during storage. Simulations of leakage for the limiting case of CO 2 migrating vertically from an areally extensive emplacement in the lower portion of a reservoir showed similar strong persistence of LCT. This research has two broad implications for GCS. The first is that LCT can retain a significant fraction of the CO 2 stored in a reservoir – above and beyond the residual saturation -- if the overlying seal were to fail. Thus frameworks for risk assessment should be extended to account for LCT. The second implication is that compared to pressure driven flow in reservoirs, CO 2 migration and trapping behave in a qualitatively different manner in heterogeneous reservoirs when buoyancy is the dominant driving force for flow. Thus simulations of GCS that neglect capillary heterogeneity will fail to capture important features of the CO 2 plume. While commercial reservoir simulation software can account for fine scale capillary heterogeneity, it has not been designed to work efficiently with such domains, and no simulators can handle fine-scale resolution throughout the reservoir. A possible way to upscale the migration and trapping is to apply an “effective residual saturation” to coarse-scale grids. While the extent of overall immobilization can be correlated in this way, all coarser grids failed to capture the distance traveled by the migrating CO 2 for large gravity number. Thus it remains unclear how best to account for LCT in the routine simulation work-flow that will be needed for large-scale GCS. Alternatives meriting investigation include streamline methods, reduced-physics proxies (e.g. particle tracking), and biased invasion percolation algorithms, which are based on precisely the capillary heterogeneity essential for LCT.« less

MULTILEVEL ISCHEMIA IN DISORGANIZATION OF THE RETINAL INNER LAYERS ON PROJECTION-RESOLVED OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY.

PubMed

Onishi, Alex C; Ashraf, Mohammed; Soetikno, Brian T; Fawzi, Amani A

2018-04-10

To examine the relationship between ischemia and disorganization of the retinal inner layers (DRIL). Cross-sectional retrospective study of 20 patients (22 eyes) with diabetic retinopathy presenting to a tertiary academic referral center, who had DRIL on structural optical coherence tomography (OCT) using Spectralis HRA + OCT (Heidelberg Engineering, Heidelberg, Germany) and OCT angiography with XR Avanti (Optovue Inc, Fremont, CA) on the same day. Optical coherence tomography angiography images were further processed to remove flow signal projection artifacts using a software algorithm adapted from recent studies. Retinal capillary perfusion in the superficial capillary plexuses, middle capillary plexuses, and deep capillary plexuses, as well as integrity of the photoreceptor lines on OCT was compared in areas with DRIL to control areas without DRIL in the same eye. Qualitative assessment of projection-resolved OCT angiography of eyes with DRIL on structural OCT demonstrated significant perfusion deficits compared with adjacent control areas (P < 0.001). Most lesions (85.7%) showed superimposed superficial capillary plexus and/or middle capillary plexus nonperfusion in addition to deep capillary plexus nonflow. Areas of DRIL were significantly associated with photoreceptor disruption (P = 0.035) compared with adjacent DRIL-free areas. We found that DRIL is associated with multilevel retinal capillary nonperfusion, suggesting an important role for ischemia in this OCT phenotype.

Thermal Performance of Surface Wick Structures.

NASA Astrophysics Data System (ADS)

Chen, Yongkang; Tavan, Noel; Baker, John; Melvin, Lawrence; Weislogel, Mark

2010-03-01

Microscale surface wick structures that exploit capillary driven flow in interior corners have been designed. In this study we examine the interplay between capillary flow and evaporative heat transfer that effectively reduces the surface temperature. The tests are performed by raising the surface temperature to various levels before the flow is introduced to the surfaces. Certainly heat transfer weakens the capillary driven flow. It is observed, however, the surface temperature can be reduced significantly. The effects of geometric parameters and interconnectivity are to be characterized to identify optimal configurations.

Development and study of a heat pipe with dielectric properties

NASA Astrophysics Data System (ADS)

Semena, M. G.; Gershuni, A. N.; Chepurnoi, A. B.

Requirements for the structural elements of heat pipes with dielectric properties are examined. To obtain information necessary for the thermal analysis of heat pipes, a study is made of the capillary-transport characteristics of a dielectric capillary structure consisting of quartz fibers; the capillary pressure and the liquid penetration coefficient are determined. The results of the study are used to develop dielectric heat pipes for the cooling of a vacuum electronic instrument. Experimentally determined characteristics of the heat pipes are presented.

Design of Capillary Flows with Spatially Graded Porous Films

NASA Astrophysics Data System (ADS)

Joung, Young Soo; Figliuzzi, Bruno Michel; Buie, Cullen

2013-11-01

We have developed a new capillary tube model, consisting of multi-layered capillary tubes oriented in the direction of flow, to predict capillary speeds on spatially graded porous films. Capillary flows through thin porous media have been widely utilized for small size liquid transport systems. However, for most media it is challenging to realize arbitrary shapes and spatially functionalized micro-structures with variable flow properties. Therefore, conventional media can only be used for capillary flows obeying Washburn's equation and the modifications thereof. Given this background, we recently developed a method called breakdown anodization (BDA) to produce highly wetting porous films. The resulting surfaces show nearly zero contact angles and fast water spreading speed. Furthermore, capillary pressure and spreading diffusivity can be expressed as functions of capillary height when customized electric fields are used in BDA. From the capillary tube model, we derived a general capillary flow equation of motion in terms of capillary pressure and spreading diffusivity. The theoretical model shows good agreement with experimental capillary flows. The study will provide novel design methodologies for paper-based microfluidic devices.

Methods of forming and using porous structures for energy efficient separation of light gases by capillary condensation

DOEpatents

Calamur, Narasimhan; Carrera, Martin E.; Devlin, David J.; Archuleta, Tom

2000-01-01

The present invention relates to an improved method and apparatus for separating one or more condensable compounds from a mixture of two or more gases of differing volatilities by capillary fractionation in a membrane-type apparatus, and a method of forming porous structures therefor. More particularly, the invention includes methods of forming and using an apparatus consisting, at least in part, of a porous structure having capillary-type passages extending between a plurality of small openings on the first side and larger openings on a second side of the structure, the passages being adapted to permit a condensed liquid to flow therethrough substantially by capillary forces, whereby vapors from the mixture are condensed, at least in part, and substantially in and adjacent to the openings on the first side, and are caused to flow in a condensed liquid state, substantially in the absence of vapor, from the openings on the first side to the openings on the second side.

Connective Tissue Growth Factor Is Involved in Structural Retinal Vascular Changes in Long-Term Experimental Diabetes

PubMed Central

Van Geest, Rob J.; Leeuwis, Jan Willem; Dendooven, Amélie; Pfister, Frederick; Bosch, Klazien; Hoeben, Kees A.; Vogels, Ilse M.C.; Van der Giezen, Dionne M.; Dietrich, Nadine; Hammes, Hans-Peter; Goldschmeding, Roel; Klaassen, Ingeborg; Van Noorden, Cornelis J.F.

2014-01-01

Early retinal vascular changes in the development of diabetic retinopathy (DR) include capillary basal lamina (BL) thickening, pericyte loss and the development of acellular capillaries. Expression of the CCN (connective tissue growth factor/cysteine-rich 61/nephroblastoma overexpressed) family member CCN2 or connective tissue growth factor (CTGF), a potent inducer of the expression of BL components, is upregulated early in diabetes. Diabetic mice lacking one functional CTGF allele (CTGF+/−) do not show this BL thickening. As early events in DR may be interrelated, we hypothesized that CTGF plays a role in the pathological changes of retinal capillaries other than BL thickening. We studied the effects of long-term (6-8 months) streptozotocin-induced diabetes on retinal capillary BL thickness, numbers of pericytes and the development of acellular capillaries in wild type and CTGF+/− mice. Our results show that an absence of BL thickening of retinal capillaries in long-term diabetic CTGF+/− mice is associated with reduced pericyte dropout and reduced formation of acellular capillaries. We conclude that CTGF is involved in structural retinal vascular changes in diabetic rodents. Inhibition of CTGF in the eye may therefore be protective against the development of DR. PMID:24217924

Transmission of Microsporidian Parasites of Mosquitoes.

DTIC Science & Technology

1982-01-01

finely drawn capillary tube calibrated to approximately 1 il. Cholesterol and 20-hydroxyecdysone were dissolved in insect saline with 10% ethanol... saline . Sharpened jeweler’s forceps were then used to remove the ovaries through single ventral incisions between the 6th and 7th abdominal sternites... saline (PBS) in a tissue grinder and then subjected to 2 cycles of differential centrifugation. The spores are then layered onto 0-10% Ludox IIS-40

Scanning Electron Microscopic Structure of the Lingual Papillae of the Common Opossum (Didelphis marsupialis)

NASA Astrophysics Data System (ADS)

Okada, Shigenori; Schraufnagel, Dean E.

2005-08-01

The mammalian tongue has evolved for specialized functions in different species. The structure of its papillae tells about the animal's diet, habit, and taxonomy. The opossum has four kinds of lingual papillae (filiform, conical, fungiform, vallate). Scanning electron microscopy of the external features, connective tissue cores, and corrosion casts of the microvasculature show the filiform papillae have a spearhead-like main process and spiny accessory processes around the apical part of the main process. The shape and number of both processes depend on their position on the tongue. On the apex, the main processes have shovel-like capillary networks and the accessory processes have small conical networks. On the lingual radix, the processes have small capillary loops. In the patch region, conical papillae have capillaries arranged as a full sail curving posteriorly. The fungiform papillae are scattered among the filiform papillae and have capillary baskets beneath each taste bud. Giant fungiform papillae on the tongue tip are three to four times larger than the ones on the lingual body. Capillaries of giant papillae form a fan-shaped network. The opossum has three vallate papillae arranged in a triangle. Their tops have secondary capillary loops but not their lateral surfaces. Mucosal folds on the posterolateral border have irregular, fingerlike projections with cylindrical capillary networks. These findings and the structure of the rest of the masticatory apparatus suggest the lingual papillae of opossum have kept their ancestral carnivorous features but also developed the herbivore characteristics of other marsupials.

Scanning electron microscopic structure of the lingual papillae of the common opossum (Didelphis marsupialis).

PubMed

Okada, Shigenori; Schraufnagel, Dean E

2005-08-01

The mammalian tongue has evolved for specialized functions in different species. The structure of its papillae tells about the animal's diet, habit, and taxonomy. The opossum has four kinds of lingual papillae (filiform, conical, fungiform, vallate). Scanning electron microscopy of the external features, connective tissue cores, and corrosion casts of the microvasculature show the filiform papillae have a spearhead-like main process and spiny accessory processes around the apical part of the main process. The shape and number of both processes depend on their position on the tongue. On the apex, the main processes have shovel-like capillary networks and the accessory processes have small conical networks. On the lingual radix, the processes have small capillary loops. In the patch region, conical papillae have capillaries arranged as a full sail curving posteriorly. The fungiform papillae are scattered among the filiform papillae and have capillary baskets beneath each taste bud. Giant fungiform papillae on the tongue tip are three to four times larger than the ones on the lingual body. Capillaries of giant papillae form a fan-shaped network. The opossum has three vallate papillae arranged in a triangle. Their tops have secondary capillary loops but not their lateral surfaces. Mucosal folds on the posterolateral border have irregular, fingerlike projections with cylindrical capillary networks. These findings and the structure of the rest of the masticatory apparatus suggest the lingual papillae of opossum have kept their ancestral carnivorous features but also developed the herbivore characteristics of other marsupials.

Microvascular remodelling in preeclampsia: quantifying capillary rarefaction accurately and independently predicts preeclampsia.

PubMed

Antonios, Tarek F T; Nama, Vivek; Wang, Duolao; Manyonda, Isaac T

2013-09-01

Preeclampsia is a major cause of maternal and neonatal mortality and morbidity. The incidence of preeclampsia seems to be rising because of increased prevalence of predisposing disorders, such as essential hypertension, diabetes, and obesity, and there is increasing evidence to suggest widespread microcirculatory abnormalities before the onset of preeclampsia. We hypothesized that quantifying capillary rarefaction could be helpful in the clinical prediction of preeclampsia. We measured skin capillary density according to a well-validated protocol at 5 consecutive predetermined visits in 322 consecutive white women, of whom 16 subjects developed preeclampsia. We found that structural capillary rarefaction at 20-24 weeks of gestation yielded a sensitivity of 0.87 with a specificity of 0.50 at the cutoff of 2 capillaries/field with the area under the curve of the receiver operating characteristic value of 0.70, whereas capillary rarefaction at 27-32 weeks of gestation yielded a sensitivity of 0.75 and a higher specificity of 0.77 at the cutoff of 8 capillaries/field with area under the curve of the receiver operating characteristic value of 0.82. Combining capillary rarefaction with uterine artery Doppler pulsatility index increased the sensitivity and specificity of the prediction. Multivariable analysis shows that the odds of preeclampsia are increased in women with previous history of preeclampsia or chronic hypertension and in those with increased uterine artery Doppler pulsatility index, but the most powerful and independent predictor of preeclampsia was capillary rarefaction at 27-32 weeks. Quantifying structural rarefaction of skin capillaries in pregnancy is a potentially useful clinical marker for the prediction of preeclampsia.

Compliance with dietary guidelines affects capillary recruitment in healthy middle-aged men and women.

PubMed

Govoni, Virginia; Sanders, Thomas A B; Reidlinger, Dianne P; Darzi, Julia; Berry, Sarah E E; Goff, Louise M; Seed, Paul T; Chowienczyk, Philip J; Hall, Wendy L

2017-04-01

Healthy microcirculation is important to maintain the health of tissues and organs, most notably the heart, kidney and retina. Single components of the diet such as salt, lipids and polyphenols may influence microcirculation, but the effects of dietary patterns that are consistent with current dietary guidelines are uncertain. It was hypothesized that compliance to UK dietary guidelines would have a favourable effect on skin capillary density/recruitment compared with a traditional British diet (control diet). A 12-week randomized controlled trial in men and women aged 40-70 years was used to test whether skin microcirculation, measured by skin video-capillaroscopy on the dorsum of the finger, influenced functional capillary density (number of capillaries perfused under basal conditions), structural capillary density (number of anatomical capillaries perfused during finger cuff inflation) and capillary recruitment (percentage difference between structural and functional capillary density). Microvascular measures were available for 137 subjects out of the 165 participants randomized to treatment. There was evidence of compliance to the dietary intervention, and participants randomized to follow dietary guidelines showed significant falls in resting supine systolic, diastolic and mean arterial pressure of 3.5, 2.6 and 2.9 mmHg compared to the control diet. There was no evidence of differences in capillary density, but capillary recruitment was 3.5 % (95 % CI 0.2, 6.9) greater (P = 0.04) on dietary guidelines compared with control. Adherence to dietary guidelines may help maintain a healthy microcirculation in middle-aged men and women. This study is registered at www.isrctn.com as ISRCTN92382106.

Structural and functional changes in the microcirculation of lepromatous leprosy patients - Observation using orthogonal polarization spectral imaging and laser Doppler flowmetry iontophoresis

PubMed Central

Treu, Curt; de Souza, Maria das Graças Coelho; Lupi, Omar; Sicuro, Fernando Lencastre; Maranhão, Priscila Alves; Kraemer-Aguiar, Luiz Guilherme; Bouskela, Eliete

2017-01-01

Leprosy is a chronic granulomatous infection of skin and peripheral nerves caused by Mycobacterium leprae and is considered the main infectious cause of disability worldwide. Despite the several studies regarding leprosy, little is known about its effects on microvascular structure and function in vivo. Thus, we have aimed to compare skin capillary structure and functional density, cutaneous vasomotion (spontaneous oscillations of arteriolar diameter), which ensures optimal blood flow distribution to skin capillaries) and cutaneous microvascular blood flow and reactivity between ten men with lepromatous leprosy (without any other comorbidity) and ten age- and gender-matched healthy controls. Orthogonal polarization spectral imaging was used to evaluate skin capillary morphology and functional density and laser Doppler flowmetry to evaluate blood flow, vasomotion and spectral analysis of flowmotion (oscillations of blood flow generated by vasomotion) and microvascular reactivity, in response to iontophoresis of acetylcholine and sodium nitroprusside. The contribution of different frequency components of flowmotion (endothelial, neurogenic, myogenic, respiratory and cardiac) was not statistically different between groups. However, endothelial-dependent and -independent vasodilatations elicited by acetylcholine and sodium nitroprusside iontophoresis, respectively, were significantly reduced in lepromatous leprosy patients compared to controls, characterizing the existence of microvascular dysfunction. These patients also presented a significant increase in the number of capillaries with morphological abnormalities and in the diameters of the dermal papilla and capillary bulk when compared to controls. Our results suggest that lepromatous leprosy causes severe microvascular dysfunction and significant alterations in capillary structure. These structural and functional changes are probably induced by exposure of the microvascular bed to chronic inflammation evoked by the Mycobacterium leprae. PMID:28419120

Microstructural Evolution of Al2O3-ZrO2 (Y2O3) Composites and its Correlation with Toughness

NASA Astrophysics Data System (ADS)

Kim, Hee Seung; Seo, Mi Young; Kim, Ik Jin

2008-02-01

The microstructure of zirconia (ZrO2) toughened alumina (Al2O3) ceramics was carefully controlled so as to obtain dense and fine-grained ceramics, thereby improving the properties and reliability of the ceramics for capillary applications in semiconductor bonding technology. Al2O3-ZrO2(Y2O3) composite was produced via Ceramic Injection Molding (CIM) technology, followed by Sinter-HIP process. Room temperature strength, hardness, Young's modulus, thermal expansion coefficient and toughness were determined, as well as surface strengthening induced by the fine grained homogenous microstructure and the thermal treatment. The changes in alumina/zirconia grain size, sintering condition and HIP treatment were found to be correlated.

Capillarics: pre-programmed, self-powered microfluidic circuits built from capillary elements.

PubMed

Safavieh, Roozbeh; Juncker, David

2013-11-07

Microfluidic capillary systems employ surface tension effects to manipulate liquids, and are thus self-powered and self-regulated as liquid handling is structurally and chemically encoded in microscale conduits. However, capillary systems have been limited to perform simple fluidic operations. Here, we introduce complex capillary flow circuits that encode sequential flow of multiple liquids with distinct flow rates and flow reversal. We first introduce two novel microfluidic capillary elements including (i) retention burst valves and (ii) robust low aspect ratio trigger valves. These elements are combined with flow resistors, capillary retention valves, capillary pumps, and open and closed reservoirs to build a capillary circuit that, following sample addition, autonomously delivers a defined sequence of multiple chemicals according to a preprogrammed and predetermined flow rate and time. Such a circuit was used to measure the concentration of C-reactive protein. This work illustrates that as in electronics, complex capillary circuits may be built by combining simple capillary elements. We define such circuits as "capillarics", and introduce symbolic representations. We believe that more complex circuits will become possible by expanding the library of building elements and formulating abstract design rules.

Capillary waveguide optrodes: an approach to optical sensing in medical diagnostics

NASA Astrophysics Data System (ADS)

Lippitsch, Max E.; Draxler, Sonja; Kieslinger, Dietmar; Lehmann, Hartmut; Weigl, Bernhard H.

1996-07-01

Glass capillaries with a chemically sensitive coating on the inner surface are used as optical sensors for medical diagnostics. A capillary simultaneously serves as a sample compartment, a sensor element, and an inhomogeneous optical waveguide. Various detection schemes based on absorption, fluorescence intensity, or fluorescence lifetime are described. In absorption-based capillary waveguide optrodes the absorption in the sensor layer is analyte dependent; hence light transmission along the inhomogeneous waveguiding structure formed by the capillary wall and the sensing layer is a function of the analyte concentration. Similarly, in fluorescence-based capillary optrodes the fluorescence intensity or the fluorescence lifetime of an indicator dye fixed in the sensing layer is analyte dependent; thus the specific property of fluorescent light excited in the sensing layer and thereafter guided along the inhomogeneous waveguiding structure is a function of the analyte concentration. Both schemes are experimentally demonstrated, one with carbon dioxide as the analyte and the other one with oxygen. The device combines optical sensors with the standard glass capillaries usually applied to gather blood drops from fingertips, to yield a versatile diagnostic instrument, integrating the sample compartment, the optical sensor, and the light-collecting optics into a single piece. This ensures enhanced sensor performance as well as improved handling compared with other sensors. waveguide, blood gases, medical diagnostics.

Construction of stable capillary networks using a microfluidic device.

PubMed

Sudo, Ryo

2015-01-01

Construction of stable capillary networks is required to provide sufficient oxygen and nutrients to the deep region of thick tissues, which is important in the context of 3D tissue engineering. Although conventional in vitro culture models have been used to investigate the mechanism of capillary formation, recent advances in microfluidics technologies allowed us to control biophysical and biochemical culture environments more precisely, which led to the construction of functional and stable capillary networks. In this study, endothelial cells and mesenchymal stem cells were co-cultured in microfluidic devices to construct stable capillary networks, which resulted in the construction of luminal structures covered by pericytes. Interactions between endothelial cells and mesenchymal stem cells are also discussed in the context of capillary formation.

Abnormalities of capillary microarchitecture in a rat model of coronary ischemic congestive heart failure

PubMed Central

Chen, Jiqiu; Yaniz-Galende, Elisa; Kagan, Heather J.; Liang, Lifan; Hekmaty, Saboor; Giannarelli, Chiara

2015-01-01

The aim of the present study is to explore the role of capillary disorder in coronary ischemic congestive heart failure (CHF). CHF was induced in rats by aortic banding plus ischemia-reperfusion followed by aortic debanding. Coronary arteries were perfused with plastic polymer containing fluorescent dye. Multiple fluorescent images of casted heart sections and scanning electric microscope of coronary vessels were obtained to characterize changes in the heart. Cardiac function was assessed by echocardiography and in vivo hemodynamics. Stenosis was found in all levels of the coronary arteries in CHF. Coronary vasculature volume and capillary density in remote myocardium were significantly increased in CHF compared with control. This occurred largely in microvessels with a diameter of ≤3 μm. Capillaries in CHF had a tortuous structure, while normal capillaries were linear. Capillaries in CHF had inconsistent diameters, with assortments of narrowed and bulged segments. Their surfaces appeared rough, potentially indicating endothelial dysfunction in CHF. Segments of main capillaries between bifurcations were significantly shorter in length in CHF than in control. Transiently increasing preload by injecting 50 μl of 30% NaCl demonstrated that the CHF heart had lower functional reserve; this may be associated with congestion in coronary microcirculation. Ischemic coronary vascular disorder is not limited to the main coronary arteries, as it occurs in arterioles and capillaries. Capillary disorder in CHF included stenosis, deformed structure, proliferation, and roughened surfaces. This disorder in the coronary artery architecture may contribute to the reduction in myocyte contractility in the setting of heart failure. PMID:25659485

Comparative quantitative study of astrocytes and capillary distribution in optic nerve laminar regions.

PubMed

Balaratnasingam, Chandrakumar; Kang, Min H; Yu, Paula; Chan, Geoffrey; Morgan, William H; Cringle, Stephen J; Yu, Dao-Yi

2014-04-01

Retinal ganglion cell (RGC) axonal structure and function in the optic nerve head (ONH) is predominantly supported by astrocytes and capillaries. There is good experimental evidence to demonstrate that RGC axons are perturbed in a non-uniform manner following ONH injury and it is likely that the pattern of RGC axonal modification bears some correlation with the quantitative properties of astrocytes and capillaries within laminar compartments. Although there have been some excellent topographic studies concerning glial and microvascular networks in the ONH our knowledge regarding the quantitative properties of these structures are limited. This report is an in-depth quantitative, structural analysis of astrocytes and capillaries in the pre laminar, lamina cribrosa and post laminar compartments of the ONH. 49 optic nerves from human (n = 10), pig (n = 12), horse (n = 6), rat (n = 11) and rabbit (n = 10) eyes are studied. Immunohistochemical and high-magnification confocal microscopy techniques are used to co-localise astrocytes, capillaries and nuclei in the mid-portion of the optic nerve. Quantitative methodology is used to determine the area occupied by astrocyte processes, microglia processes, nuclei density and the area occupied by capillaries in each laminar compartment. Comparisons are made within and between species. Relationships between ONH histomorphometry and astrocyte-capillary constitution are also explored. This study demonstrates that there are significant differences in the quantitative properties of capillaries and astrocytes between the laminar compartments of the human ONH. Astrocyte processes occupied the greatest area in the lamina cribrosa compartment of the human ONH implicating it as an area of great metabolic demands. Microglia were found to occupy only a small proportion of tissue in the rat, rabbit and pig optic nerve suggesting that the astrocyte is the predominant glia cell type in the optic nerve. This study also demonstrates that there is significant uniformity, with respect to astrocyte and capillary constitution, in the post laminar region of species with an unmyelinated anterior optic nerve. This implicates an important role served by oligodendrocytes and myelin in governing the structural characteristics of the post laminar optic nerve. Finally, this study demonstrates that eyes with similar lamina cribrosa structure do not necessarily share an identical cellular constitution with respect to astrocytes. The quantitative properties of astrocytes in the pre laminar and lamina cribrosa regions of the rat, which has a rudimentary lamina cribrosa with only a few collagenous beams, shared more similarities to the human eye than the pig or horse. The quantitative properties of astrocytes and capillaries in the laminar compartments of the ONH provide a basis for understanding the pathogenic mechanisms that are involved in diseases such as glaucoma and ischemic optic neuropathy. The findings in this study also provide valuable information about the distinct advantages of different animal models for studying human optic nerve diseases. Utilisation of structural data provided in this report together with emerging in vivo technology may potentially permit the early identification of RGC axonal injury by quantifying changes in ONH capillaries and astrocytes. Copyright © 2014 Elsevier Ltd. All rights reserved.

Transient studies of capillary-induced flow

NASA Technical Reports Server (NTRS)

Reagan, M. K.; Bowman, W. J.

1993-01-01

This paper presents the numerical and experimental results of a study performed on the transient rise of fluid in a capillary tube. The capillary tube problem provides an excellent mechanism from which to launch an investigation into the transient flow of a fluid in a porous wick structure where capillary forces must balance both adverse gravitational effects and frictional losses. For the study, a capillary tube, initially charged with a small volume of water, was lowered into a pool of water. The behavior of the column of fluid during the transient that followed as more water entered the tube from the pool was both numerically and experimentally studied.

Image-Based Modeling of Blood Flow and Oxygen Transfer in Feto-Placental Capillaries

PubMed Central

Brownbill, Paul; Janáček, Jiří; Jirkovská, Marie; Kubínová, Lucie; Chernyavsky, Igor L.; Jensen, Oliver E.

2016-01-01

During pregnancy, oxygen diffuses from maternal to fetal blood through villous trees in the placenta. In this paper, we simulate blood flow and oxygen transfer in feto-placental capillaries by converting three-dimensional representations of villous and capillary surfaces, reconstructed from confocal laser scanning microscopy, to finite-element meshes, and calculating values of vascular flow resistance and total oxygen transfer. The relationship between the total oxygen transfer rate and the pressure drop through the capillary is shown to be captured across a wide range of pressure drops by physical scaling laws and an upper bound on the oxygen transfer rate. A regression equation is introduced that can be used to estimate the oxygen transfer in a capillary using the vascular resistance. Two techniques for quantifying the effects of statistical variability, experimental uncertainty and pathological placental structure on the calculated properties are then introduced. First, scaling arguments are used to quantify the sensitivity of the model to uncertainties in the geometry and the parameters. Second, the effects of localized dilations in fetal capillaries are investigated using an idealized axisymmetric model, to quantify the possible effect of pathological placental structure on oxygen transfer. The model predicts how, for a fixed pressure drop through a capillary, oxygen transfer is maximized by an optimal width of the dilation. The results could explain the prevalence of fetal hypoxia in cases of delayed villous maturation, a pathology characterized by a lack of the vasculo-syncytial membranes often seen in conjunction with localized capillary dilations. PMID:27788214

Endothelial cell differentiation into capillary-like structures in response to tumour cell conditioned medium: a modified chemotaxis chamber assay.

PubMed

Garrido, T; Riese, H H; Aracil, M; Pérez-Aranda, A

1995-04-01

We have developed a modified chemotaxis chamber assay in which bovine aortic endothelial (BAE) cells degrade Matrigel basement membrane and migrate and form capillary-like structures on type I collagen. This capillary formation occurs in the presence of conditioned media from highly metastatic tumour cell lines, such as B16F10 murine melanoma or MDA-MD-231 human breast adenocarcinoma, but not in the presence of conditioned medium (CM) from the less invasive B16F0 cell line. Replacement of tumour cell CM by 10 ng ml-1 basic fibroblast growth factor (bFGF) also results in capillary-like structure formation by BAE cells. An anti-bFGF antibody blocks this effect, showing that bFGF is one of the factors responsible for the angiogenic response induced by B16F10 CM in our assay. Addition of an anti-laminin antibody reduces significantly the formation of capillary-like structures, probably by blocking the attachment of BAE cells to laminin present in Matrigel. The anti-angiogenic compound suramin inhibits in a dose-dependent manner (complete inhibition with 100 microM suramin) the migration and differentiation of BAE cells on type I collagen in response to B16F10 CM. This assay represents a new model system to study tumour-induced angiogenesis in vitro.

Unlocking the Physiochemical Controls on Organic Carbon Dynamics from the Soil Pore- to Core-Scale

NASA Astrophysics Data System (ADS)

Smith, A. P.; Tfaily, M. M.; Bond-Lamberty, B. P.; Todd-Brown, K. E.; Bailey, V. L.

2015-12-01

The physical organization of soil includes pore networks of varying size and connectivity. These networks control microbial access to soil organic carbon (C) by spatially separating microorganisms and C by both distance and size exclusion. The extent to which this spatially isolated C is vulnerable to microbial transformation under hydrologically dynamic conditions is unknown, and limits our ability to predict the source and sink capacity of soils. We investigated the effects of shifting hydrologic connectivity and soil structure on greenhouse gas C emissions from surface soils collected from the Disney Wilderness Preserve (Florida, USA). We subjected intact soil cores and re-packed homogenized soil cores to simulated groundwater rise or precipitation, monitoring their CO2 and CH4 emissions over 24 hours. Soil pore water was then extracted from each core using different suctions to sample water retained by pore throats of different sizes and then characterized by Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry. Greater respiration rates were observed from homogenized cores compared to intact cores, and from soils wet from below, in which the wetting front is driven by capillary forces, filling fine pores first. This suggests that C located in fine pores may turn over via diffusion processes that lead to the colocation of this C with other resources and microorganisms. Both the complexity and concentration of soluble-C increased with decreasing pore size domains. Pore water extracted from homogenized cores had greater C concentrations than from intact cores, with the greatest concentrations in pore waters sampled from very fine pores, highlighting the importance of soil structure in physically protecting C. These results suggest that the spatial separation of decomposers from C is a key mechanism stabilizing C in these soils. Further research is ongoing to accurately represent this protection mechanism, and the conditions under which it breaks down, in new and improved Earth system models.

Effect of heterogeneity and anisotropy related to the construction method on transfer processes in waste rock piles.

PubMed

Lahmira, Belkacem; Lefebvre, René; Aubertin, Michel; Bussière, Bruno

2016-01-01

Waste rock piles producing acid mine drainage (AMD) are partially saturated systems involving multiphase (gas and liquid) flow and coupled transfer processes. Their internal structure and heterogeneous properties are inherited from their wide-ranging material grain sizes, their modes of deposition, and the underlying topography. This paper aims at assessing the effect of physical heterogeneity and anisotropy of waste rock piles on the physical processes involved in the generation of AMD. Generic waste rock pile conditions were represented with the numerical simulator TOUGH AMD based on those found at the Doyon mine waste rock pile (Canada). Models included four randomly distributed material types (coarse, intermediate, fine and very fine-grained). The term "randomly" as used in this study means that the vertical profile and spatial distribution of materials in waste rock piles (internal structure) defy stratigraphy principles applicable to natural sediments (superposition and continuity). The materials have different permeability and capillary properties, covering the typical range of materials found in waste rock piles. Anisotropy with a larger horizontal than vertical permeability was used to represent the effect of pile construction by benches, while the construction by end-dumping was presumed to induce a higher vertical than horizontal permeability. Results show that infiltrated precipitation preferentially flows in fine-grained materials, which remain almost saturated, whereas gas flows preferentially through the most permeable coarse materials, which have higher volumetric gas saturation. Anisotropy, which depends on pile construction methods, often controls global gas flow paths. Construction by benches favours lateral air entry close to the pile slope, whereas end-dumping leads to air entry from the surface to the interior of the pile by secondary gas convection cells. These results can be useful to construct and rehabilitate waste rock piles to minimize AMD, while controlling gas flow and oxygen supply. Copyright © 2015 Elsevier B.V. All rights reserved.

Polyamidoamine dendrimer as a spacer for the immobilization of glucose oxidase in capillary enzyme microreactor.

PubMed

Wang, Siming; Su, Ping; Hongjun, E; Yang, Yi

2010-10-15

Polyamidoamine dendrimer (PAMAM) is one of a number of dendritic polymers with precise molecular structure, highly geometric symmetry, and a large number of terminal groups. In this study, different generations of PAMAM (G0-G4) were introduced onto the inner wall of fused-silica capillaries by microwave irradiation and a new type of glucose oxidase (GOx) capillary enzyme microreactor was developed based on enzyme immobilization in the prepared PAMAM-grafted fused-silica capillaries. The optimal enzymolysis conditions for beta-d-glucose in the microreactor were evaluated by capillary zone electrophoresis. In addition, the enzymolysis efficiencies of different generations of PAMAM-GOx capillary enzyme microreactor were compared. The results indicate that enzymolysis efficiency increased with increasing generations of PAMAM. The experimental results provide the possibility for the development and application of an online immobilized capillary enzyme microreactor. Crown Copyright 2010. Published by Elsevier Inc. All rights reserved.

Analysis of electrolyte transport through charged nanopores.

PubMed

Peters, P B; van Roij, R; Bazant, M Z; Biesheuvel, P M

2016-05-01

We revisit the classical problem of flow of electrolyte solutions through charged capillary nanopores or nanotubes as described by the capillary pore model (also called "space charge" theory). This theory assumes very long and thin pores and uses a one-dimensional flux-force formalism which relates fluxes (electrical current, salt flux, and fluid velocity) and driving forces (difference in electric potential, salt concentration, and pressure). We analyze the general case with overlapping electric double layers in the pore and a nonzero axial salt concentration gradient. The 3×3 matrix relating these quantities exhibits Onsager symmetry and we report a significant new simplification for the diagonal element relating axial salt flux to the gradient in chemical potential. We prove that Onsager symmetry is preserved under changes of variables, which we illustrate by transformation to a different flux-force matrix given by Gross and Osterle [J. Chem. Phys. 49, 228 (1968)JCPSA60021-960610.1063/1.1669814]. The capillary pore model is well suited to describe the nonlinear response of charged membranes or nanofluidic devices for electrokinetic energy conversion and water desalination, as long as the transverse ion profiles remain in local quasiequilibrium. As an example, we evaluate electrical power production from a salt concentration difference by reverse electrodialysis, using an efficiency versus power diagram. We show that since the capillary pore model allows for axial gradients in salt concentration, partial loops in current, salt flux, or fluid flow can develop in the pore. Predictions for macroscopic transport properties using a reduced model, where the potential and concentration are assumed to be invariant with radial coordinate ("uniform potential" or "fine capillary pore" model), are close to results of the full model.

Magnetic properties of permalloy wires in vycor capillaries

NASA Astrophysics Data System (ADS)

Lubitz, P.; Ayers, J. D.; Davis, A.

1991-11-01

Thin wires of NiFe alloys with compositions near 80% Ni were prepared by melting the alloy in vycor tubes and drawing fibers from the softened glass. The resulting fibers consist of relatively thick-walled vycor capillaries containing permalloy wires filling a few percent of the volume. The wires are continuous over considerable lengths, uniform in circular cross section, nearly free of contact with the walls and can be drawn to have diameters less than 1 μm. Their magnetic properties are generally similar to bulk permalloy, but show a variety of magnetic switching behaviors for fields along the wire axis, depending on composition, wire diameter, and thermal history. As pulled, the wires can show sharp switching, reversible rotation or mixed behavior. This method can produce NiFe alloy wires suitable for use in applications as sensor, memory or inductive elements; other alloys, such as supermalloy and sendust, also can be fabricated as fine wires by this method.

Progression of Diabetic Capillary Occlusion: A Model

PubMed Central

Gens, John Scott; Glazier, James A.; Burns, Stephen A.; Gast, Thomas J.

2016-01-01

An explanatory computational model is developed of the contiguous areas of retinal capillary loss which play a large role in diabetic maculapathy and diabetic retinal neovascularization. Strictly random leukocyte mediated capillary occlusion cannot explain the occurrence of large contiguous areas of retinal ischemia. Therefore occlusion of an individual capillary must increase the probability of occlusion of surrounding capillaries. A retinal perifoveal vascular sector as well as a peripheral retinal capillary network and a deleted hexagonal capillary network are modelled using Compucell3D. The perifoveal modelling produces a pattern of spreading capillary loss with associated macular edema. In the peripheral network, spreading ischemia results from the progressive loss of the ladder capillaries which connect peripheral arterioles and venules. System blood flow was elevated in the macular model before a later reduction in flow in cases with progression of capillary occlusions. Simulations differing only in initial vascular network structures but with identical dynamics for oxygen, growth factors and vascular occlusions, replicate key clinical observations of ischemia and macular edema in the posterior pole and ischemia in the retinal periphery. The simulation results also seem consistent with quantitative data on macular blood flow and qualitative data on venous oxygenation. One computational model applied to distinct capillary networks in different retinal regions yielded results comparable to clinical observations in those regions. PMID:27300722

Evolutionary transformations of chorioallantoic placental characters in rodentia with special reference to hystricognath species.

PubMed

Mess, Andrea

2003-09-01

The aim of this paper is to reconstruct the evolution of chorioallantoic placental characters in Rodentia. The analysis is based on pre-existing hypotheses of rodent relationships and the tracing of character evolution. Data on 64 rodent species of 49 genera are derived from the literature. New results refer to the hystricognath species Petromus typicus A. Smith, 1831 and Octodon degus (Molina, 1782). This comprehensive analysis confirms that the stem species pattern of Rodentia is characterised by a haemochorial placenta which is divided horizontally. Inside the placental labyrinth, fetal vessels and their trophoblastic external border build up a network through which the maternal blood flows. The trophoblastic tissue is one-layered, syncytial and possess a considerable surface extension. Within Rodentia, evolutionary transformations occurred on the macroscopic as well as the fine structural level. The results suggest that the stem species of Hystricognathi underwent transformations only on the macroscopic level, i.e., forming a ring-shaped arrangement of placental regions with centrally situated maternal arteries and the acquisition of a subplacenta. By contrast, in Muridae the chorioallantoic placenta shows derived features only in regard to the fine structure of the labyrinth, i.e. the interhaemal membrane is modified in composition, and the fetal capillary endothelium is fenestrated. Geomyoidea underwent transformations on both levels. Macroscopically, their placenta is modified into a hillock shape. Microscopically, the interhaemal membrane is formed by the cytotrophoblast. In addition to the mentioned transformations, some aspects of other fetal membrane differentiation in Rodentia are briefly discussed. Copyright 2003 Wiley-Liss, Inc.

About Mass Transfer in Capillaries of Biological Systems under Influence of Vibrations

NASA Astrophysics Data System (ADS)

Prisniakov, K.

Vibrations accompany the flight of the manned spacecraft both at a stage of a orbital injection to an orbit, and during long flights (as noise), rendering undesirable physiological influence on crew, reducing serviceability and creating constant discomfort. The report represents attempt to predict a state of the cosmonaut in conditions of influence of vibrations for the period of start and stay in Space, being based on researches of mass transfer processes in capillary systems. For this purpose the original researches on heat and mass transfer processes with evaporation of liquids in capillary - porous structures in conditions of vibration actions and changes of a direction of action of gravitation are generalized. Report demonstrates the existence of modes at which increased or lowered mass transfer is achieved on border of separation "liquid - gas". The possible mechanism of influence of vibrations on evaporation of a liquid in capillaries is examined. The magnitudes of frequencies and amplitudes are submitted at which minimax characteristics are observed. The opportunity of application of the developed mathematical model of heat and mass transfer in capillary - porous structures to forecasting influence of vibrations for biological processes in capillaries of alive essences is analyzed. Such approach is justified on the mechanical nature of harmful influence of vibrations on an organism of the person. In addition the range of vibration frequencies which arise during space flights, corresponds to own resonant frequencies of a human body and his separate organs. Comparison of these resonant frequencies of a body of the person (5-80 Hertz) with vibration frequencies of optimum modes of heat and mass transfer in capillary - porous structures (20-40 Hertz) is shown their ranges of coverage. It gives the basis to assume existence of similar effects in capillaries of human body. It is supposed, that the difficulty of breath, change of a rhythm of breath, the subsequent weariness under vibration action are attributable to infringements of normal mass transfer between the inhaled air and blood. The opportunity of use of the received laws is discussed for assessment of influence of gravitational fields on intensity mass transfer in capillaries of biosystems also.

Physical reconstruction of packed beds and their morphological analysis: core-shell packings as an example.

PubMed

Bruns, Stefan; Tallarek, Ulrich

2011-04-08

We report a fast, nondestructive, and quantitative approach to characterize the morphology of packed beds of fine particles by their three-dimensional reconstruction from confocal laser scanning microscopy images, exemplarily shown for a 100μm i.d. fused-silica capillary packed with 2.6μm-sized core-shell particles. The presented method is generally applicable to silica-based capillary columns, monolithic or particulate, and comprises column pretreatment, image acquisition, image processing, and statistical analysis of the image data. It defines a unique platform for fundamental comparisons of particulate and monolithic supports using the statistical measures derived from their reconstructions. Received morphological data are column cross-sectional porosity profiles and chord length distributions from the interparticle macropore space, which are a descriptor of local density and can be characterized by a simplified k-gamma distribution. This distribution function provides a parameter of location and a parameter of dispersion which can be correlated to individual chromatographic band broadening processes (i.e., to transchannel and short-range interchannel contributions to eddy dispersion, respectively). Together with the transcolumn porosity profile the presented approach allows to analyze and quantify the packing microstructure from pore to column scale and therefore holds great promise in a comparative study of packing conditions and particle properties, particularly for characterizing and minimizing the packing process-specific heterogeneities in the final bed structure. Copyright © 2011 Elsevier B.V. All rights reserved.

[THE STRUCTURE OF LYMPHATIC CAPILLARIES OF THE CILIARY BODY OF THE HUMAN EYE].

PubMed

Borodin, Yu I; Bgatova, N P; Chernykh, V V; Trunov, A N; Pozhidayeva, A A; Konenkov, V I

2015-01-01

Using light microscopy, immunohistochemistry and electron microscopy, the structural organization of interstitial spaces and vessels of the ciliary body of the human eye (n = 5) were studied. The ciliary body was found to contain wide interstitial spaces--tissue clefts bound by collagen fibers and fibroblasts. Organ-specific lymphatic capillaries were also demonstrated in the ciliary body. According to the present findings and the lymphatic region concept, the first 2 elements of the lymphatic region of the eye were described: tissue clefts--prelymphatics and lymphatic capillaries of the ciliary body. The third element of the lymphatic region are the lymph nodes of the head and neck.

Formation of natural gas hydrates in marine sediments 1. Conceptual model of gas hydrate growth conditioned by host sediment properties

USGS Publications Warehouse

Clennell, M.B.; Hovland, M.; Booth, J.S.; Henry, P.; Winters, W.J.

1999-01-01

The stability of submarine gas hydrates is largely dictated by pressure and temperature, gas composition, and pore water salinity. However, the physical properties and surface chemistry of deep marine sediments may also affect the thermodynamic state, growth kinetics, spatial distributions, and growth forms of clathrates. Our conceptual model presumes that gas hydrate behaves in a way analogous to ice in a freezing soil. Hydrate growth is inhibited within fine-grained sediments by a combination of reduced pore water activity in the vicinity of hydrophilic mineral surfaces, and the excess internal energy of small crystals confined in pores. The excess energy can be thought of as a "capillary pressure" in the hydrate crystal, related to the pore size distribution and the state of stress in the sediment framework. The base of gas hydrate stability in a sequence of fine sediments is predicted by our model to occur at a lower temperature (nearer to the seabed) than would be calculated from bulk thermodynamic equilibrium. Capillary effects or a build up of salt in the system can expand the phase boundary between hydrate and free gas into a divariant field extending over a finite depth range dictated by total methane content and pore-size distribution. Hysteresis between the temperatures of crystallization and dissociation of the clathrate is also predicted. Growth forms commonly observed in hydrate samples recovered from marine sediments (nodules, and lenses in muds; cements in sands) can largely be explained by capillary effects, but kinetics of nucleation and growth are also important. The formation of concentrated gas hydrates in a partially closed system with respect to material transport, or where gas can flush through the system, may lead to water depletion in the host sediment. This "freeze-drying" may be detectable through physical changes to the sediment (low water content and overconsolidation) and/or chemical anomalies in the pore waters and metastable presence of free gas within the normal zone of hydrate stability. 

Intermediate-Scale Investigation of Capillary and Dissolution Trapping during CO2 Injection and Post-Injection in Heterogeneous Geological Formations

NASA Astrophysics Data System (ADS)

Cihan, A.; Illangasekare, T. H.; Zhou, Q.; Birkholzer, J. T.; Rodriguez, D.

2010-12-01

The capillary and dissolution trapping processes are believed to be major trapping mechanisms during CO2 injection and post-injection in heterogeneous subsurface environments. These processes are important at relatively shorter time periods compared to mineralization and have a strong impact on storage capacity and leakage risks, and they are suitable to investigate at reasonable times in the laboratory. The objectives of the research presented is to investigate the effect of the texture transitions and variability in heterogeneous field formations on the effective capillary and dissolution trapping at the field scale through multistage analysis comprising of experimental and modeling studies. A series of controlled experiments in intermediate-scale test tanks are proposed to investigate the key processes involving (1) viscous fingering of free-phase CO2 along high-permeability (or high-K) fast flow pathways, (2) dynamic intrusion of CO2 from high-K zones into low-K zones by capillarity (as well as buoyancy), (3) diffusive transport of dissolved CO2 into low-K zones across large interface areas, and (4) density-driven convective mass transfer into CO2-free regions. The test tanks contain liquid sampling ports to measure spatial and temporal changes in concentration of dissolved fluid as the injected fluid migrates. In addition to visualization and capturing images through digital photography, X-ray and gamma attenuation methods are used to measure phase saturations. Heterogeneous packing configurations are created with tightly packed sands ranging from very fine to medium fine to mimic sedimentary rocks at potential storage formations. Effect of formation type, injection pressure and injection rate on trapped fluid fraction are quantified. Macroscopic variables such as saturation, pressure and concentration that are measured will be used for testing the existing macroscopic models. The applicability of multiphase flow theories will be evaluated by comparing with the experimental data. Existing upscaling methodologies will be tested using experimental data for accurately estimating parameters of the large-scale heterogeneous porous media. This paper presents preliminary results from the initial-stage experiments and the modeling analysis. In the future, we will design and conduct a comprehensive set of experiments for improving the fundamental understanding of the processes, and refine and calibrate the models simulating the effective capillary and dissolution trapping with an ultimate goal to design efficient and safe storage schemes.

Functionalized core-shell hydrogel microsprings by anisotropic gelation with bevel-tip capillary

PubMed Central

Yoshida, Koki; Onoe, Hiroaki

2017-01-01

This study describes a novel microfluidic-based method for the synthesis of hydrogel microsprings that are capable of encapsulating various functional materials. A continuous flow of alginate pre-gel solution can spontaneously form a hydrogel microspring by anisotropic gelation around the bevel-tip of the capillary. This technique allows fabrication of hydrogel microsprings using only simple capillaries and syringe pumps, while their complex compartmentalization characterized by a laminar flow inside the capillary can contribute to the optimization of the microspring internal structure and functionality. Encapsulation of several functional materials including magnetic-responsive nanoparticles or cell dispersed collagen for tissue scaffold was demonstrated to functionalize the microsprings. Our core-shell hydrogel microsprings have immense potential for application in a number of fields, including biological/chemical microsensors, biocompatible soft robots/microactuators, drug release, self-assembly of 3D structures and tissue engineering. PMID:28378803

Lymphocyte migration in the micro-channel of splenic sheathed capillaries in Chinese soft-shelled turtles, Pelodiscus sinensis.

PubMed

Zhang, Qian; Ullah, Shakeeb; Liu, Yi; Yang, Ping; Chen, Bing; Waqas, Yasir; Bao, Huijun; Hu, Lisi; Li, Quanfu; Chen, Qiusheng

2016-01-01

The structural characteristics of the splenic sheathed capillary were investigated using light microscopy and transmission electron microscopy (TEM). This study mainly focused on lymphocyte migration to the splenic white pulp via micro-channels in Chinese soft-shelled turtles, Pelodiscus sinensis. The results showed that the sheathed capillaries in the turtle spleen were high endothelial venule (HEV)-like vessels. These capillaries consist of micro-channels that facilitate lymphocyte migration to the splenic white pulp. The micro-channel is a dynamic structure comprising processes of endothelial cells, supporting cells, and ellipsoid-associated cells (EACs), which provides a microenvironment for lymphocyte migration. The pattern of lymphocyte migration in the micro-channel of the turtle spleen includes the following steps: (i) lymphocyte first adheres to the endothelium of the sheathed capillary, passes through the endothelial cells, and traverses through the basement membrane of the sheathed capillary; (ii) it then enters into the ellipsoid combined with supporting cells and EACs; and (iii) lymphocyte migrates from the ellipsoid to the periellipsoidal lymphatic sheath (PELS) via the micro-channel. This study provides morphological evidence for lymphocyte migration in the micro-channels of turtle spleens and also an insight into the mechanism of lymphocyte homing to the splenic white pulp of reptiles. Copyright © 2015 Elsevier Ltd. All rights reserved.

In vivo assessment of the structure of skin microcirculation by reflectance confocal-laser-scanning microscopy

NASA Astrophysics Data System (ADS)

Sugata, Keiichi; Osanai, Osamu; Kawada, Hiromitsu

2012-02-01

One of the major roles of the skin microcirculation is to supply oxygen and nutrition to the surrounding tissue. Regardless of the close relationship between the microcirculation and the surrounding tissue, there are few non-invasive methods that can evaluate both the microcirculation and its surrounding tissue at the same site. We visualized microcapillary plexus structures in human skin using in vivo reflectance confocal-laser-scanning microscopy (CLSM), Vivascope 3000® (Lucid Inc., USA) and Image J software (National Institutes of Health, USA) for video image processing. CLSM is a non-invasive technique that can visualize the internal structure of the skin at the cellular level. In addition to internal morphological information such as the extracellular matrix, our method reveals capillary structures up to the depth of the subpapillary plexus at the same site without the need for additional optical systems. Video images at specific depths of the inner forearm skin were recorded. By creating frame-to-frame difference images from the video images using off-line video image processing, we obtained images that emphasize the brightness depending on changes of intensity coming from the movement of blood cells. Merging images from different depths of the skin elucidates the 3-dimensional fine line-structure of the microcirculation. Overall our results show the feasibility of a non-invasive, high-resolution imaging technique to characterize the skin microcirculation and the surrounding tissue.

Laser beam coupling with capillary discharge plasma for laser wakefield acceleration applications

NASA Astrophysics Data System (ADS)

Bagdasarov, G. A.; Sasorov, P. V.; Gasilov, V. A.; Boldarev, A. S.; Olkhovskaya, O. G.; Benedetti, C.; Bulanov, S. S.; Gonsalves, A.; Mao, H.-S.; Schroeder, C. B.; van Tilborg, J.; Esarey, E.; Leemans, W. P.; Levato, T.; Margarone, D.; Korn, G.

2017-08-01

One of the most robust methods, demonstrated to date, of accelerating electron beams by laser-plasma sources is the utilization of plasma channels generated by the capillary discharges. Although the spatial structure of the installation is simple in principle, there may be some important effects caused by the open ends of the capillary, by the supplying channels etc., which require a detailed 3D modeling of the processes. In the present work, such simulations are performed using the code MARPLE. First, the process of capillary filling with cold hydrogen before the discharge is fired, through the side supply channels is simulated. Second, the simulation of the capillary discharge is performed with the goal to obtain a time-dependent spatial distribution of the electron density near the open ends of the capillary as well as inside the capillary. Finally, to evaluate the effectiveness of the beam coupling with the channeling plasma wave guide and of the electron acceleration, modeling of the laser-plasma interaction was performed with the code INF&RNO.

Hysteresis of the Contact Angle of a Meniscus Inside a Capillary with Smooth, Homogeneous Solid Walls.

PubMed

Kuchin, Igor V; Starov, Victor M

2016-05-31

A theory of contact angle hysteresis of a meniscus inside thin capillaries with smooth, homogeneous solid walls is developed in terms of surface forces (disjoining/conjoining pressure isotherm) using a quasi-equilibrium approach. The disjoining/conjoining pressure isotherm includes electrostatic, intermolecular, and structural components. The values of the static receding θr, advancing θa, and equilibrium θe contact angles in thin capillaries were calculated on the basis of the shape of the disjoining/conjoining pressure isotherm. It was shown that both advancing and receding contact angles depend on the capillary radius. The suggested mechanism of the contact angle hysteresis has a direct experimental confirmation: the process of receding is accompanied by the formation of thick β-films on the capillary walls. The effect of the transition from partial to complete wetting in thin capillaries is predicted and analyzed. This effect takes place in very thin capillaries, when the receding contact angle decreases to zero.

Anisotropic capillary barrier for waste site surface covers

DOEpatents

Stormont, J.C.

1996-08-27

Waste sites are capped or covered upon closure. The cover structure incorporates a number of different layers each having a contributory function. One such layer is the barrier layer. Traditionally the barriers have been compacted soil and geosynthetics. These types of barriers have not been successfully implemented in unsaturated ground conditions like those found in dry climates. Capillary barriers have been proposed as barrier layers in dry environments, but the divergence length of these barriers has been found to be inadequate. An alternative to the capillary barrier is a anisotropic capillary barrier. An anisotropic capillary barrier has an increased divergence length which results in more water being diverted laterally preventing the majority of water from percolating in a downward direction through the barrier. 10 figs.

Anisotropic capillary barrier for waste site surface covers

DOEpatents

Stormont, John C.

1996-01-01

Waste sites are capped or covered upon closure. The cover structure incorporates a number of different layers each having a contributory function. One such layer is the barrier layer. Traditionally the barriers have been compacted soil and geosynthetics. These types of barriers have not been successfully implemented in unsaturated ground conditions like those found in dry climates. Capillary barriers have been proposed as barrier layers in dry environments, but the divergence length of these barriers has been found to be inadequate. An alternative to the capillary barrier is a anisotropic capillary barrier. An anisotropic capillary barrier has an increased divergence length which results in more water being diverted laterally preventing the majority of water from percolating in a downward direction through the barrier.

Acquisition system testing with superfluid helium. [cryopumping for space

NASA Technical Reports Server (NTRS)

Anderson, John E.; Fester, Dale A.; Dipirro, Michael J.

1988-01-01

Minus one-g outflow tests were conducted with superfluid helium in conjunction with a thermomechanical pump setup in order to study the use of capillary acquisition systems for NASA's Superfluid Helium On-Orbit Transfer (SHOOT) flight experiment. Results show that both fine mesh screen and porous sponge systems are capable of supplying superfluid helium to the thermomechanical pump inlet against a one-g head up to 4 cm, fulfilling the SHOOT requirements. Sponge results were found to be reproducible, while the screen results were not.

Quantitative evaluation of capillaroscopic microvascular changes in patients with established coronary heart disease.

PubMed

Sanchez-Garcia, M Esther; Ramirez-Lara, Irene; Gomez-Delgado, Francisco; Yubero-Serrano, Elena M; Leon-Acuña, Ana; Marin, Carmen; Alcala-Diaz, Juan F; Camargo, Antonio; Lopez-Moreno, Javier; Perez-Martinez, Pablo; Tinahones, Francisco José; Ordovas, Jose M; Caballero, Javier; Blanco-Molina, Angeles; Lopez-Miranda, Jose; Delgado-Lista, Javier

2018-02-23

Microcirculation disturbances have been associated to most of the cardiovascular risk factors as well as to multiple inflammatory diseases. However, whether these abnormalities are specifically augmented in patients with coronary heart disease is still unknown. We aimed to evaluate if there is a relationship between the presence of coronary heart disease and the existence of functional and structural capillary abnormalities evaluated in the cutaneous microcirculation by videocapillaroscopy. Two matched samples of 30 participants with and without coronary heart disease but with similar clinical and anthropometric characteristics were evaluated by videocapillaroscopy at the dorsal skin of the third finger of the non-dominant hand. We calculated basal capillary density as well as capillary density after a period of arterial and venous occlusion in order to evaluate functionality and maximum capillary density. We also measured capillary recruitment. Microvascular capillary density at rest was significantly lower in patients suffering from coronary heart disease than in controls. This fact was also found after dynamic tests (arterial and venous occlusion), suggesting functional impairments. Capillary recruitment of the samples was not different in our sample. In our study, patients with coronary heart disease exhibit functional and structural microvascular disturbances. Although this is a very preliminary study, these findings open the door for further studying the microvascular functionality in coronary patients and how it relates to the response to treatment and/or the prognosis of the disease. Copyright © 2017 Elsevier España, S.L.U. All rights reserved.

Water on Mars: Evidence from MER Mission Results

NASA Technical Reports Server (NTRS)

Landis, Geoffrey A.

2004-01-01

The Viking and the Mars Exploration Rover missions observed that the surface of Mars is encrusted by a thinly cemented layer, or "duricrust". Elemental analyzes at five sites on Mars show that these soils have sulfur content and chlorine content consistent with the presence of sulfates and halides as mineral cements. The soil is highly enriched in the salt-forming elements compared with rock. Analysis of the soil cementation indicates some features which may be evidence of liquid water. At both MER sites, duricrust textures revealed by the Microscopic Imager show features including the presence of fine sand-sized grains, some of which may be aggregates of fine silt and clay, surrounded by a pervasive light colored material that is associated with microtubular structures and networks of microfractures. Stereo views of undisturbed duricrust surfaces reveal rugged microrelief between 2-3 mm and minimal loose material. Comparisons of microscopic images of duricrust soils obtain before and after placement of the Mossbauer spectrometer indicate differing degrees of compaction and cementation. Two models of a transient water hypothesis are offered, a "top down" hypothesis that emphasizes the surface deposition of frost, melting and downward migration of liquid water and a "bottom up" alternative that proposes the presence of interstitial ice/brine, with the upward capillary migration of liquid water. The viability of both of these models ultimately hinges on the availability of seasonally transient liquid water for brief periods.

CAPILLARY CONDENSATION IN MMS AND PORE STRUCTURE CHARACTERIZATION. (R825959)

EPA Science Inventory

Phenomena of capillary condensation and desorption in siliceous mesoporous molecular sieves (MMS) with cylindrical channels are studied by means of the non-local density functional theory (NLDFT). The results are compared with macroscopic thermodynamic approaches based on Kelv...

Influence of addition of calcium sulfate dihydrate on drying of autoclaved aerated concrete

NASA Astrophysics Data System (ADS)

Małaszkiewicz, Dorota; Chojnowski, Jacek

2017-11-01

The quality of the autoclaved aerated concrete (AAC) strongly depends on the chemical composition of the raw materials, as well as on the process of the hydrothermal reaction during autoclaving. Performance parameters depend on material structure: fine micron-scale matrix porosity generated by the packing of thin tobermorite plates and coarse aeration pores arising from the foaming of wet mix. In this study the binder varied in calcium sulfate dihydrate (CaSO4ṡ2H2O) content. Five series of AAC specimens were produced, with gypsum content 0; 0.55; 1.15; 2.3 and 3.5% of dry mass respectively. AAC units were produced in UNIPOL technology. The study presents experimental results of AAC moisture stabilization. The initial moisture content was determined directly after autoclaving. Slower drying process was observed for samples containing over 2% of gypsum. Whereas other performance parameters, compressive and tensile strength, as well as water absorption and capillary rise, were significantly better comparing to the reference AAC samples.

Simultaneous submicrometric 3D imaging of the micro-vascular network and the neuronal system in a mouse spinal cord

PubMed Central

Fratini, Michela; Bukreeva, Inna; Campi, Gaetano; Brun, Francesco; Tromba, Giuliana; Modregger, Peter; Bucci, Domenico; Battaglia, Giuseppe; Spanò, Raffaele; Mastrogiacomo, Maddalena; Requardt, Herwig; Giove, Federico; Bravin, Alberto; Cedola, Alessia

2015-01-01

Faults in vascular (VN) and neuronal networks of spinal cord are responsible for serious neurodegenerative pathologies. Because of inadequate investigation tools, the lacking knowledge of the complete fine structure of VN and neuronal system represents a crucial problem. Conventional 2D imaging yields incomplete spatial coverage leading to possible data misinterpretation, whereas standard 3D computed tomography imaging achieves insufficient resolution and contrast. We show that X-ray high-resolution phase-contrast tomography allows the simultaneous visualization of three-dimensional VN and neuronal systems of ex-vivo mouse spinal cord at scales spanning from millimeters to hundreds of nanometers, with nor contrast agent nor sectioning and neither destructive sample-preparation. We image both the 3D distribution of micro-capillary network and the micrometric nerve fibers, axon-bundles and neuron soma. Our approach is very suitable for pre-clinical investigation of neurodegenerative pathologies and spinal-cord-injuries, in particular to resolve the entangled relationship between VN and neuronal system. PMID:25686728

Multiscale sensorless adaptive optics OCT angiography system for in vivo human retinal imaging.

PubMed

Ju, Myeong Jin; Heisler, Morgan; Wahl, Daniel; Jian, Yifan; Sarunic, Marinko V

2017-11-01

We present a multiscale sensorless adaptive optics (SAO) OCT system capable of imaging retinal structure and vasculature with various fields-of-view (FOV) and resolutions. Using a single deformable mirror and exploiting the polarization properties of light, the SAO-OCT-A was implemented in a compact and easy to operate system. With the ability to adjust the beam diameter at the pupil, retinal imaging was demonstrated at two different numerical apertures with the same system. The general morphological structure and retinal vasculature could be observed with a few tens of micrometer-scale lateral resolution with conventional OCT and OCT-A scanning protocols with a 1.7-mm-diameter beam incident at the pupil and a large FOV (15 deg× 15 deg). Changing the system to a higher numerical aperture with a 5.0-mm-diameter beam incident at the pupil and the SAO aberration correction, the FOV was reduced to 3 deg× 3 deg for fine detailed imaging of morphological structure and microvasculature such as the photoreceptor mosaic and capillaries. Multiscale functional SAO-OCT imaging was performed on four healthy subjects, demonstrating its functionality and potential for clinical utility. (2017) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE).

The Relationship Between Microscopic Grain Surface Structure and the Dynamic Capillary-Driven Advance of Water Films over Individual Dry Natural Sand Grains

NASA Astrophysics Data System (ADS)

Kibbey, T. C. G.; Adegbule, A.; Yan, S.

2017-12-01

The movement of nonvolatile solutes in unsaturated porous media at low water contents depends on transport in surface-associated water films. The focus of the work described here was on studying solute movement in water films advancing by capillary forces over initially-dry grain surfaces, to understand how microscopic surface roughness features influence the initial velocity of water film advance. For this work, water containing a non-adsorbing conservative tracer was used to track the movement of advancing water films. A stainless steel capillary tube connected to an external reservoir a fixed distance below the grain surface was used to transmit solution to the grain surface under negative pressure (positive capillary pressure), consistent with conditions that might be expected in the unsaturated zone. The small internal diameter of the capillary prevents solution from draining out of the capillary back into the reservoir. When the capillary is contacted with a grain surface, capillary forces that result from contact between the fluid and the rough grain surface cause water films to wick across the grain surface. Multiple experiments were conducted on the same grain, rotating the grain and varying the capillary contact point around the circumference of the grain. Imaging was conducted at fixed intervals using an automated Extended Depth of Field (EDF) imaging system, and images were analyzed to determine initial velocity. Grain surfaces were then characterized through scanning electron microscope (SEM) imaging, using a hybrid stereoscopic reconstruction method designed to extract maximum detail in creating elevation maps of geologic surfaces from tilted pairs of SEM images. The resulting elevation maps were used to relate surface roughness profiles around the grain with initial velocities. Results suggest that velocity varies significant with contact point around an individual grain, and correlates quantitatively with the local grain surface structure. Preliminary simulation results will also be discussed.

Drop Tower Experiments concerning Fluid Management under Microgravity

NASA Astrophysics Data System (ADS)

Gaulke, Diana; Dreyer, Michael

2012-07-01

Transport and positioning of liquid under microgravity is done utilizing capillary forces. Therefore, capillary transport processes have to be understood for a wide variety of space applications, ranging from propellant management in tanks of space transportation systems to eating and drinking devices for astronauts. There are two types of liquid transportation in microgravity using capillary forces. First, the driven liquid flow in open channels where the capillary forces at free surfaces ensure a gas and vapor free flow. Here it is important to know the limiting flow rate through such an open channel before the free surface collapses and gas is sucked into the channel. A number of different experiments at the drop tower Bremen, on sounding rockets and at the ISS have been conducted to analyse this phenomenon within different geometries. As result a geometry dependent theory for calculating the maximum flow rate has been found. On the other hand liquid positioning and transportation requires the capillary pressure of curved surfaces to achieve a liquid flow to a desired area. Especially for space applications the weight of structure has to be taken into account for development. For example liquid positioning in tanks can be achieved via a complicated set of structure filling the whole tank resulting in heavy devices not reasonable in space applications. Astrium developed in cooperation with ZARM a propellant management device much smaller than the tank volume and ensuring a gas and vapour free supply of propellant to the propulsion system. In the drop tower Bremen a model of this device was tested concerning different microgravity scenarios. To further decrease weight and ensure functionality within different scenarios structure elements are designed as perforated geometries. Capillary transport between perforated plates has been analyzed concerning the influence of geometrical pattern of perforations. The conducted experiments at the drop tower Bremen show the remarkable influence of perforations on the capillary transport capability.

Impairment of Skin Capillary Recruitment Precedes Chronic Complications in Patients with Type 1 Diabetes

PubMed Central

Tibirica, Eduardo; Rodrigues, Elba; Cobas, Roberta; Gomes, Marilia B.

2007-01-01

Microvascular function in patients with type 1 diabetes without chronic complications was assessed using skin capillary recruitment during post-occlusive reactive hyperemia (PORH). Structural (maximal) capillary density was evaluated during venous occlusion. The study included 48 consecutive outpatients aged 26.3 ± 10.8 years with type 1 diabetes (duration of 9.5 years) without chronic complications and 34 control subjects. Intravital capillary video-microscopy was used in the dynamic study of skin capillaries in the dorsum of the fingers and toes. Capillary recruitment during PORH (% increase in mean capillary density, MCD) was significantly higher in the controls than the patients in both the fingers (p < 0.001) and toes (p < 0.001). During venous occlusion, MCD increase was also higher in the controls than the patients in both the fingers (p < 0.05) and toes (p < 0.0001). In patients, no difference was found between MCD at baseline and after venous occlusion in the fingers but a decrease was observed in the toes (p < 0.001). It is concluded that skin capillary function is significantly impaired in both fingers and toes of patients with type 1 diabetes without chronic complications. Moreover, capillary density during venous occlusion did not increase in either extremity in the patients, suggesting that their capillaries at rest are already maximally recruited. PMID:17823692

Running exercise protects the capillaries in white matter in a rat model of depression.

PubMed

Chen, Lin-Mu; Zhang, Ai-Pin; Wang, Fei-Fei; Tan, Chuan-Xue; Gao, Yuan; Huang, Chun-Xia; Zhang, Yi; Jiang, Lin; Zhou, Chun-Ni; Chao, Feng-Lei; Zhang, Lei; Tang, Yong

2016-12-01

Running has been shown to improve depressive symptoms when used as an adjunct to medication. However, the mechanisms underlying the antidepressant effects of running are not fully understood. Changes of capillaries in white matter have been discovered in clinical patients and depression model rats. Considering the important part of white matter in depression, running may cause capillary structural changes in white matter. Chronic unpredictable stress (CUS) rats were provided with a 4-week running exercise (from the fifth week to the eighth week) for 20 minutes each day for 5 consecutive days each week. Anhedonia was measured by a behavior test. Furthermore, capillary changes were investigated in the control group, the CUS/Standard group, and the CUS/Running group using stereological methods. The 4-week running increased sucrose consumption significantly in the CUS/Running group and had significant effects on the total volume, total length, and total surface area of the capillaries in the white matter of depression rats. These results demonstrated that exercise-induced protection of the capillaries in white matter might be one of the structural bases for the exercise-induced treatment of depression. It might provide important parameters for further study of the vascular mechanisms of depression and a new research direction for the development of clinical antidepressant means. J. Comp. Neurol. 524:3577-3586, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Influence of mixing conditions on the rheological properties and structure of capillary suspensions

PubMed Central

Bossler, Frank; Weyrauch, Lydia; Schmidt, Robert; Koos, Erin

2017-01-01

The rheological properties of a suspension can be dramatically altered by adding a small amount of a secondary fluid that is immiscible with the bulk liquid. These capillary suspensions exist either in the pendular state where the secondary fluid preferentially wets the particles or the capillary state where the bulk fluid is preferentially wetting. The yield stress, as well as storage and loss moduli, depends on the size and distribution of secondary phase droplets created during sample preparation. Enhanced droplet breakup leads to stronger sample structures. In capillary state systems, this can be achieved by increasing the mixing speed and time of turbulent mixing using a dissolver stirrer. In the pendular state, increased mixing speed also leads to better droplet breakup, but spherical agglomeration is favored at longer times decreasing the yield stress. Additional mixing with a ball mill is shown to be beneficial to sample strength. The influence of viscosity variance between the bulk and second fluid on the droplet breakup is excluded by performing experiments with viscosity-matched fluids. These experiments show that the capillary state competes with the formation of Pickering emulsion droplets and is often more difficult to achieve than the pendular state. PMID:28194044

Study on the characteristics of a two gap capillary discharge

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang, D.; Yang, L. J., E-mail: yanglj@mail.xjtu.edu.cn; Huo, P.

2015-02-15

The paper presents a new two-gap capillary (TGC) discharge structure. The prominent innovation is the introduction of the middle electrode, which divides the capillary into the trigger gap and the main gap. The discharge circuit of the TGC comprises the trigger circuit and the main circuit. The two circuits are used for the pre-ionization of the trigger gap and providing energy of 450 J for the main gap arc discharging, respectively. When the discharge initiates, the trigger gap is pre-ionized under high voltage pulse produced by trigger circuit, and meanwhile, the weakly ionized plasma is generated. The main circuit then maintainsmore » the expansion of the plasma, which is called soft capillary discharge. Afterwards, the main gap is shorted and discharges under a relatively low voltage. With the optimization of the circuit parameter, both the energy deposition ratio in main gap and the degree of plasma ionization are enhanced. The efficiency of the energy deposition is almost twice higher compared with that of the conventional capillary structure. The life performance test indicates that the erosion of the middle electrode and the trigger gap carbonization are the key factors that limit the life performance of the TGC.« less

Characterization and Modeling of Fine-Pitch Copper Ball Bonding on a Cu/Low- k Chip

NASA Astrophysics Data System (ADS)

Che, F. X.; Wai, L. C.; Zhang, Xiaowu; Chai, T. C.

2015-02-01

Cu ball bonding faces more challenges than Au ball bonding, for example, excessive deformation of the bond pad and damage of Cu/low- k structures, because of the much greater hardness of Cu free air balls. In this study, dynamic finite-element analysis (FEA) modeling with displacement control was developed to simulate the ball-bonding process. The three-dimensional (3D) FEA simulation results were confirmed by use of stress-measurement data, obtained by use of stress sensors built into the test chip. Stress comparison between two-dimensional (2D) and 3D FEA models showed the 2D plain strain model to be a reasonable and effective model for simulation of the ball-bonding process without loss of accuracy; it also saves computing resources. The 2D FEA model developed was then used in studies of a Cu/low- k chip to find ways of reducing Al bond pad deformation and stresses of low- k structures. The variables studied included Al pad properties, capillary geometry, bond pad design (Al pad thickness, Al pad coated with Ni layer), and the effect of ultrasonic bonding power.

[Structure of newly formed capillaries of the rabbit cornea (electron microscopic study)].

PubMed

Gurina, O Iu; Karaganov, Ia L

1984-08-01

Owing to a complex application of topical analysis and tracer technique, it is possible to carry out a light optic and electron microscopic investigation of newly formed capillaries growing in the rabbit cornea after its chemical burn. The ultrastructural analysis demonstrates certain polymorphism of morphological organization of endotheliocyte in the newly formed capillaries. There is a rather elevated amount of free ribosomes, mitochondria, microtubules and microfilaments in cytoplasm. The granular endoplasmic reticulum and Golgi complex are hypertrophied. Weibel--Palade bodies appear. Taking into account certain morpho-functional peculiarities of endothelial cells along the course of the growing capillaries, on the 8th day of growth three zone are distinguished: 1--area of nondifferentiated endothelium (apex of the capillary), 2--transitional zone, 3--zone of relatively differentiated endothelium situating in the place where the capillary gets off the parental vessel. According to the zones distinguished, the ways of trans-endothelial transport of molecules are investigated. In formation of the capillary barrier-transport function an important role belongs to polymorphism of the endothelial cells along the course of the growing capillary which is determined by differentiation degree of these cells depending on their participation in permeability.

Cutaneous water collection by a moisture-harvesting lizard, the thorny devil (Moloch horridus).

PubMed

Comanns, Philipp; Withers, Philip C; Esser, Falk J; Baumgartner, Werner

2016-11-01

Moisture-harvesting lizards, such as the Australian thorny devil, Moloch horridus, have the remarkable ability to inhabit arid regions. Special skin structures, comprising a micro-structured surface with capillary channels in between imbricate overlapping scales, enable the lizard to collect water by capillarity and transport it to the mouth for ingestion. The ecological role of this mechanism is the acquisition of water from various possible sources such as rainfall, puddles, dew, condensation on the skin, or absorption from moist sand, and we evaluate here the potential of these various sources for water uptake by M. horridus The water volume required to fill the skin capillary system is 3.19% of body mass. Thorny devils standing in water can fill their capillary system and then drink from this water, at approximately 0.7 µl per jaw movement. Thorny devils standing on nearly saturated moist sand could only fill the capillary channels to 59% of their capacity, and did not drink. However, placing moist sand on skin replicas showed that the capillary channels could be filled from moist sand when assisted by gravity, suggesting that their field behaviour of shovelling moist sand onto the dorsal skin might fill the capillary channels and enable drinking. Condensation facilitated by thermal disequilibrium between a cool thorny devil and warm moist air provided skin capillary filling to approximately 0.22% of body weight, which was insufficient for drinking. Our results suggest that rain and moist sand seem to be ecologically likely water sources for M. horridus on a regular basis. © 2016. Published by The Company of Biologists Ltd.

Molecular transport through capillaries made with atomic-scale precision

NASA Astrophysics Data System (ADS)

Radha, B.; Esfandiar, A.; Wang, F. C.; Rooney, A. P.; Gopinadhan, K.; Keerthi, A.; Mishchenko, A.; Janardanan, A.; Blake, P.; Fumagalli, L.; Lozada-Hidalgo, M.; Garaj, S.; Haigh, S. J.; Grigorieva, I. V.; Wu, H. A.; Geim, A. K.

2016-10-01

Nanometre-scale pores and capillaries have long been studied because of their importance in many natural phenomena and their use in numerous applications. A more recent development is the ability to fabricate artificial capillaries with nanometre dimensions, which has enabled new research on molecular transport and led to the emergence of nanofluidics. But surface roughness in particular makes it challenging to produce capillaries with precisely controlled dimensions at this spatial scale. Here we report the fabrication of narrow and smooth capillaries through van der Waals assembly, with atomically flat sheets at the top and bottom separated by spacers made of two-dimensional crystals with a precisely controlled number of layers. We use graphene and its multilayers as archetypal two-dimensional materials to demonstrate this technology, which produces structures that can be viewed as if individual atomic planes had been removed from a bulk crystal to leave behind flat voids of a height chosen with atomic-scale precision. Water transport through the channels, ranging in height from one to several dozen atomic planes, is characterized by unexpectedly fast flow (up to 1 metre per second) that we attribute to high capillary pressures (about 1,000 bar) and large slip lengths. For channels that accommodate only a few layers of water, the flow exhibits a marked enhancement that we associate with an increased structural order in nanoconfined water. Our work opens up an avenue to making capillaries and cavities with sizes tunable to ångström precision, and with permeation properties further controlled through a wide choice of atomically flat materials available for channel walls.

Pulsed high energy synthesis of fine metal powders

NASA Technical Reports Server (NTRS)

Witherspoon, F. Douglas (Inventor); Massey, Dennis W. (Inventor)

1999-01-01

Repetitively pulsed plasma jets generated by a capillary arc discharge at high stagnation pressure (>15,000 psi) and high temperature (>10,000 K) are utilized to produce 0.1-10 .mu.m sized metal powders and decrease cost of production. The plasma jets impact and atomize melt materials to form the fine powders. The melt can originate from a conventional melt stream or from a pulsed arc between two electrodes. Gas streams used in conventional gas atomization are replaced with much higher momentum flux plasma jets. Delivering strong incident shocks aids in primary disintegration of the molten material. A series of short duration, high pressure plasma pulses fragment the molten material. The pulses introduce sharp velocity gradients in the molten material which disintegrates into fine particles. The plasma pulses have peak pressures of approximately one kilobar. The high pressures improve the efficiency of disintegration. High gas flow velocities and pressures are achieved without reduction in gas density. Repetitively pulsed plasma jets will produce powders with lower mean size and narrower size distribution than conventional atomization techniques.

Changes of choroidal neovascularization in indocyanine green angiography after intravitreal ranibizumab injection.

PubMed

Lee, Ji Eun; Kim, Hyun Woong; Lee, Sang Joon; Lee, Joo Eun

2015-05-01

To investigate vascular structural changes of choroidal neovascularization (CNV) followed by intravitreal ranibizumab injections using indocyanine green angiography. A total of 31 patients with exudative age-related macular degeneration and CNV whose structures were identifiable in indocyanine green angiography were included. Ranibizumab was injected into the vitreous cavity once a month for 3 months and then as needed for the next 3 months prospectively. Indocyanine green angiography was performed at baseline, 3, and 6 months. Early to midphase images of the indocyanine green angiography in the details of vascular structure of the CNV were discerned the best were used in the image analysis. Vascular structures of CNV were described as arteriovenular and capillary components, and structural changes were assessed. Arteriovenular components were observed in 29 eyes (94%). Regression of the capillary components was observed in most cases. Although regression of arteriovenular component was noted in 14 eyes (48%), complete resolution was not observed. The eyes were categorized into 3 groups according to CNV structural changes: the regressed (Group R, 10 eyes, 31%), the matured (Group M, 7 eyes, 23%), and the growing (Group G, 14 eyes, 45%). In Group R, there was no regrowth of CNV found at 6 months. In Group M, distinct vascular structures were observed at 3 months and persisted without apparent changes at 6 months. In Group G, growth or reperfusion of capillary components from the persisting arteriovenular components was noted at 6 months. Both capillary and arteriovenular components were regressed during monthly ranibizumab injections. However, CNV regrowth was observed in a group of patients during the as-needed treatment phase.

Acoustic fine structure may encode biologically relevant information for zebra finches.

PubMed

Prior, Nora H; Smith, Edward; Lawson, Shelby; Ball, Gregory F; Dooling, Robert J

2018-04-18

The ability to discriminate changes in the fine structure of complex sounds is well developed in birds. However, the precise limit of this discrimination ability and how it is used in the context of natural communication remains unclear. Here we describe natural variability in acoustic fine structure of male and female zebra finch calls. Results from psychoacoustic experiments demonstrate that zebra finches are able to discriminate extremely small differences in fine structure, which are on the order of the variation in acoustic fine structure that is present in their vocal signals. Results from signal analysis methods also suggest that acoustic fine structure may carry information that distinguishes between biologically relevant categories including sex, call type and individual identity. Combined, our results are consistent with the hypothesis that zebra finches can encode biologically relevant information within the fine structure of their calls. This study provides a foundation for our understanding of how acoustic fine structure may be involved in animal communication.

Preferential flow, connectivity and the principle of "minimum time to equilibrium": a new perspective on environmental water flow

NASA Astrophysics Data System (ADS)

Zehe, E.; Blume, T.; Bloeschl, G.

2008-12-01

Preferential/rapid flow and transport is known as one key process in soil hydrology for more than 20 years. It seems to be rather the rule, than the exception. It occurs in soils, in surface rills and river networks. If connective preferential are present at any scale, they crucially control water flow and solute transport. Why? Is there an underlying principle? If energy is conserved a system follows Fermat's principle of minimum action i.e. it follows the trajectory that minimise the integral of the total energy/ La Grangian over time. Hydrological systems are, however, non-conservative as surface and subsurface water flows dissipate energy. From thermodynamics it is well known that natural processes minimize the free energy of the system. For hydrological systems we suggest, therefore, that flow in a catchment arranges in such a way that time to a minimum of free energy becomes minimal for a given rainfall input (disturbance) and under given constraints. Free energy in a soil is determined by potential energy and capillary energy. The pore size distribution of the soil, soil structures, depth to groundwater and most important vegetation make up the constraints. The pore size distribution determines whether potential energy or capillarity dominates the free energy of the soil system. The first term is minimal when the pore space is completely de-saturated the latter becomes minimal at soil saturation. Hence, the soil determines a) the amount of excess (gravity) water that has to be exported from the soil to reach a minimum state of free energy and b) whether redistribution or groundwater recharge is more efficient to reach that equilibrium. On the other hand, the pore size distribution of the soil and the connectivity of preferential pathways (root channels, worm holes and cracks) determine flow velocities and the redistribution of water within the pore space. As water flow and ground water recharge are fast in sandy soils and capillary energy is of minor importance, connective preferential pathways do not mean any advantage for an efficient transition to an equilibrium in these systems. In fine grained soils Darcy velocities and therefore redistribution of water is 2-4 orders of magnitude slower. As capillary energy dominates in these soils an effective redistribution of water within the pore space is crucial for a fast transition of system to an equilibrium state. Connective preferential pathways ore even cracks allow a faster redistribution of water and seem therefore necessary for a fast transition into a state of minimum free energy. The suggested principle "of minimum time to equilibrium" may explain the "advantage" of preferential flow as a much more efficient dissipation of energy in fine grained soils and therefore why connective preferential pathways control environmental flow. From a fundamental, long term perspective the principle may help us to understand whether and why soil structures and even cracks evolve in different landscapes and climates and b) to link soil hydrology and (landscape) ecology. Along the lines the proposed study will present model results to test the stated hypothesis.

In situ electrochemical high-energy X-ray diffraction using a capillary working electrode cell geometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Young, Matthias J.; Bedford, Nicholas M.; Jiang, Naisheng

The ability to generate new electrochemically active materials for energy generation and storage with improved properties will likely be derived from an understanding of atomic-scale structure/function relationships during electrochemical events. Here, the design and implementation of a new capillary electrochemical cell designed specifically forin situhigh-energy X-ray diffraction measurements is described. By increasing the amount of electrochemically active material in the X-ray path while implementing low-Zcell materials with anisotropic scattering profiles, an order of magnitude enhancement in diffracted X-ray signal over traditional cell geometries for multiple electrochemically active materials is demonstrated. This signal improvement is crucial for high-energy X-ray diffraction measurementsmore » and subsequent Fourier transformation into atomic pair distribution functions for atomic-scale structural analysis. As an example, clear structural changes in LiCoO 2under reductive and oxidative conditions using the capillary cell are demonstrated, which agree with prior studies. Accurate modeling of the LiCoO 2diffraction data using reverse Monte Carlo simulations further verifies accurate background subtraction and strong signal from the electrochemically active material, enabled by the capillary working electrode geometry.« less

Monitoring refolding of tailspike endorhamnosidase using capillary electrophoresis-laser induced tryptophan fluorescence

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jensen, P.K.; Lee, Cheng S.; King, J.A.

1997-12-31

The use of capillary electrophoresis equipped with laser-induced tryptophan fluorescence detection is presented for monitoring the refolding pathway of phage P22 tailspike endorhamnosidase. Upon initiation of refolding, tailspike polypeptides rapidly fold into structured monomeric intermediates with a high content of secondary structure. These monomeric species associate to form the triple-chain defined folding intermediates, the protrimers. Conversion of the protrimer into the native, sodium dodecyl sulfate (SDS) resistant tailspike protein is the rate-limiting step in the refolding pathway. Refolding kinetics and yield measured by capillary electrophoresis are in good agreement with those obtained via native gel electrophoresis, SDS polyacrylamide gel electrophoresismore » (SDS-PAGE) and fluorescence spectrophotometry. To enhance separation resolution between protrimer and native protein in capillary electrophoresis, the use of poly(ethylene oxide) is investigated for the introduction of a sieving separation mechanism. The increased viscosity of the electrophoresis buffer may also play a role in resolution enhancement.« less

Micromachined evaporators for AMTEC cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Izenson, M.G.; Crowley, C.J.

1996-12-31

To achieve high cell efficiency and reliability, the capillary pumping system for Alkali Metal Thermal to Electric Conversion (AMTEC) must have three key characteristics: (1) very small pores to achieve a high capillary pumping head, (2) high permeability for the flow of liquid sodium to minimize internal losses, and (3) be made from a material that is exceptionally stable at high temperatures in a sodium environment. The authors have developed micromachining techniques to manufacture high performance evaporators for AMTEC cells. The evaporators have been fabricated from stainless steel, molybdenum, and a niobium alloy (Nb-1Zr). The regular, micromachined structure leads tomore » very high capillary pumping head with high permeability for liquid flow. Data from tests performed with common fluids at room temperature characterize the capillary pumping head and permeability of these structures. Three micromachined evaporators have been built into AMTEC cells and operated at temperatures up to 1,100 K. Results from these tests confirm the excellent pumping capabilities of the micromachined evaporators.« less

Fine-needle aspiration cytology of hemangiopericytoma: A report of five cases.

PubMed

Chhieng, D; Cohen, J M; Waisman, J; Fernandez, G; Cangiarella, J

1999-08-25

Hemangiopericytoma (HPC) is a relatively rare neoplasm, accounting for approximately 2.5% of all soft tissue tumors. Its histopathology has been well documented but to the authors' knowledge reports regarding its fine-needle aspiration (FNA) cytology rarely are encountered. In the current study the authors report the cytologic findings in FNA specimens from nine confirmed cases of HPC and attempt to correlate the cytologic features with the biologic outcomes. FNA was performed with or without radiologic guidance. Corresponding sections of tissue were reviewed in conjunction with the cytologic preparations. Nine FNAs were performed in 5 patients (3 men and 2 women) with an age range of 38-77 years (mean, 56 years). Two lesions were primary soft tissue lesions arising in the lower extremities; seven were recurrent or metastatic lesions from bone (one lesion), kidney (one lesion), pelvic fossa (one lesion), lower extremities (two lesions), trunk (one lesion), and breast (one lesion). All aspirates were cellular and were comprised of single and tightly packed clusters of oval to spindle-shaped cells aggregated around branched capillaries. Basement membrane material was observed in 6 cases (67%). The nuclei were uniform and oval, with finely granular chromatin and inconspicuous nucleoli in all cases except one. No mitotic figures or areas of necrosis were identified. A correct diagnosis of HPC was made on one primary lesion and all recurrent or metastatic lesions. HPCs show a spindle cell pattern in cytologic preparations and must be distinguished from more common spindle cell lesions. The presence of branched capillaries and abundant basement membrane material supports a diagnosis of HPC. Immunohistochemistry and electron microscopy performed on FNA samples may be helpful in the differential diagnosis. FNA is a useful and accurate tool with which to confirm recurrent or metastatic HPC; however, prediction of the biologic behavior of HPC based on cytologic features is not feasible. Cancer (Cancer Cytopathol) Copyright 1999 American Cancer Society.

Chemical microreactor and method thereof

DOEpatents

Morse, Jeffrey D.; Jankowski, Alan

2005-11-01

A chemical microreactor suitable for generation of hydrogen fuel from liquid sources such as ammonia, methanol, and butane through steam reforming processes when mixed with an appropriate amount of water contains capillary microchannels with integrated resistive heaters to facilitate the occurrence of catalytic steam reforming reactions. One such microreactor employs a packed catalyst capillary microchannel and at least one porous membrane. Another employs a porous membrane with a large surface area or a porous membrane support structure containing a plurality of porous membranes having a large surface area in the aggregate, i.e., greater than about 1 m.sup.2 /cm.sup.3. The packed catalyst capillary microchannels, porous membranes and porous membrane support structures may be formed by a variety of methods.

Specific Accumulation of Tumor-Derived Adhesion Factor in Tumor Blood Vessels and in Capillary Tube-Like Structures of Cultured Vascular Endothelial Cells

NASA Astrophysics Data System (ADS)

Akaogi, Kotaro; Okabe, Yukie; Sato, Junji; Nagashima, Yoji; Yasumitsu, Hidetaro; Sugahara, Kazuyuki; Miyazaki, Kaoru

1996-08-01

Tumor-derived adhesion factor (TAF) was previously identified as a cell adhesion molecule secreted by human bladder carcinoma cell line EJ-1. To elucidate the physiological function of TAF, we examined its distribution in human normal and tumor tissues. Immunochemical staining with an anti-TAF monoclonal antibody showed that TAF was specifically accumulated in small blood vessels and capillaries within and adjacent to tumor nests, but not in those in normal tissues. Tumor blood vessel-specific staining of TAF was observed in various human cancers, such as esophagus, brain, lung, and stomach cancers. Double immunofluorescent staining showed apparent colocalization of TAF and type IV collagen in the vascular basement membrane. In vitro experiments demonstrated that TAF preferentially bound to type IV collagen among various extracellular matrix components tested. In cell culture experiments, TAF promoted adhesion of human umbilical vein endothelial cells to type IV collagen substrate and induced their morphological change. Furthermore, when the endothelial cells were induced to form capillary tube-like structures by type I collagen, TAF and type IV collagen were exclusively detected on the tubular structures. The capillary tube formation in vitro was prevented by heparin, which inhibited the binding of TAF to the endothelial cells. These results strongly suggest that TAF contributes to the organization of new capillary vessels in tumor tissues by modulating the interaction of endothelial cells with type IV collagen.

Influence of capillary end effects on steady-state relative permeability estimates from direct pore-scale simulations

NASA Astrophysics Data System (ADS)

Guédon, Gaël Raymond; Hyman, Jeffrey De'Haven; Inzoli, Fabio; Riva, Monica; Guadagnini, Alberto

2017-12-01

We investigate and characterize the influence of capillary end effects on steady-state relative permeabilities obtained in pore-scale numerical simulations of two-phase flows. Our study is motivated by the observation that capillary end effects documented in two-phase laboratory-scale experiments can significantly influence permeability estimates. While numerical simulations of two-phase flows in reconstructed pore-spaces are increasingly employed to characterize relative permeabilities, a phenomenon which is akin to capillary end effects can also arise in such analyses due to the constraints applied at the boundaries of the computational domain. We profile the relative strength of these capillary end effects on the calculation of steady-state relative permeabilities obtained within randomly generated porous micro-structures using a finite volume-based two-phase flow solver. We suggest a procedure to estimate the extent of the regions influenced by these capillary end effects, which in turn allows for the alleviation of bias in the estimation of relative permeabilities.

The effect of contact angles and capillary dimensions on the burst frequency of super hydrophilic and hydrophilic centrifugal microfluidic platforms, a CFD study.

PubMed

Kazemzadeh, Amin; Ganesan, Poo; Ibrahim, Fatimah; He, Shuisheng; Madou, Marc J

2013-01-01

This paper employs the volume of fluid (VOF) method to numerically investigate the effect of the width, height, and contact angles on burst frequencies of super hydrophilic and hydrophilic capillary valves in centrifugal microfluidic systems. Existing experimental results in the literature have been used to validate the implementation of the numerical method. The performance of capillary valves in the rectangular and the circular microfluidic structures on super hydrophilic centrifugal microfluidic platforms is studied. The numerical results are also compared with the existing theoretical models and the differences are discussed. Our experimental and computed results show a minimum burst frequency occurring at square capillaries and this result is useful for designing and developing more sophisticated networks of capillary valves. It also predicts that in super hydrophilic microfluidics, the fluid leaks consistently from the capillary valve at low pressures which can disrupt the biomedical procedures in centrifugal microfluidic platforms.

The Effect of Contact Angles and Capillary Dimensions on the Burst Frequency of Super Hydrophilic and Hydrophilic Centrifugal Microfluidic Platforms, a CFD Study

PubMed Central

Kazemzadeh, Amin; Ganesan, Poo; Ibrahim, Fatimah; He, Shuisheng; Madou, Marc J.

2013-01-01

This paper employs the volume of fluid (VOF) method to numerically investigate the effect of the width, height, and contact angles on burst frequencies of super hydrophilic and hydrophilic capillary valves in centrifugal microfluidic systems. Existing experimental results in the literature have been used to validate the implementation of the numerical method. The performance of capillary valves in the rectangular and the circular microfluidic structures on super hydrophilic centrifugal microfluidic platforms is studied. The numerical results are also compared with the existing theoretical models and the differences are discussed. Our experimental and computed results show a minimum burst frequency occurring at square capillaries and this result is useful for designing and developing more sophisticated networks of capillary valves. It also predicts that in super hydrophilic microfluidics, the fluid leaks consistently from the capillary valve at low pressures which can disrupt the biomedical procedures in centrifugal microfluidic platforms. PMID:24069169

Study on stair-step liquid triggered capillary valve for microfluidic systems

NASA Astrophysics Data System (ADS)

Zhang, Lei; Jones, Ben; Majeed, Bivragh; Nishiyama, Yukari; Okumura, Yasuaki; Stakenborg, Tim

2018-06-01

In lab-on-a-chip systems, various microfluidic technologies are being developed to handle fluids at very small quantities, e.g. in the scale of nano- or pico-liter. To achieve autonomous fluid handling at a low cost, passive fluidic control, based on the capillary force between the liquid and microchannel surface, is of the utmost interest in the microsystem. Valves are an essential component for flow control in many microfluidic systems, which enables a sequence of fluidic operations to be performed. In this paper, we present a new passive valve structure for a capillary driven microfluidic device. It is a variation of a capillary trigger valve that is amenable to silicon microfabrication; it will be referred to as a stair-step liquid triggered valve. In this paper, the valve functionality and its dependencies on channel geometry, surface contact angle, and surface roughness are studied both experimentally and with numerical modeling. The effect of the contact angle was explored in experiments on the silicon microfabricated valve structure; a maximal working contact angle, above which the valve fails to be triggered, was demonstrated. The fluidic behavior in the stair-step channel structure was further explored computationally using the finite volume method with the volume-of-fluid approach. Surface roughness due to scalloping of the sidewall during the Bosch etch process was hypothesized to reduce the sidewall contact angle. The reduced contact angle has considerable impacts on the capillary pressure as the liquid vapor interface traverses the stair-step structure of the valve. An improved match in the maximal working contact angle between the experiments and model was obtained when considering this surface roughness effect.

Modification of narrow ablating capillaries under the influence of multiple femtosecond laser pulses

NASA Astrophysics Data System (ADS)

Gubin, K. V.; Lotov, K. V.; Trunov, V. I.; Pestryakov, E. V.

2016-09-01

Powerful femtosecond laser pulses that propagate through narrow ablating capillaries cause modification of capillary walls, which is studied experimentally and theoretically. At low intensities, the laser-induced periodic surface structures and porous coating composed of sub-micron particles appear on the walls. At higher intensities, the surface is covered by deposited droplets of the size up to 10 μm. In both cases, the ablated material forms a solid plug that completely blocks the capillary after several hundreds or thousands of pulses. The suggested theoretical model indicates that the plug formation is a universal effect. It must take place in any narrow tube subject to ablation under the action of short laser pulses.

Capillary Pump Loop (CPL) heat pipe development status report

NASA Technical Reports Server (NTRS)

1982-01-01

The capillary pump loop (CPL) was re-introduced as a potential candidate for the management of large heat loads. It is currently being evaluated for application in the thermal management of large space structures. Test efforts were conducted to establish the feasibility of the CPL heat pipe design.

Fine-needle aspiration cytology of malignant hemangiopericytoma of the salivary gland: A case report.

PubMed

Shimizu, K; Ogura, S; Kobayashi, T K; Kushima, R; Toyokuni, S; Iwasa, Y; Sakurai, M

1999-12-01

A 79-yr-old woman presented with a 5-yr history of swelling of the left cheek. The fine-needle aspiration (FNA) smear showed a spindle-cell neoplasm with capillaries and benign endothelial cells. The spindle cells possessed pleomorphic, hyperchromatic elongated nuclei and a moderate amount of ill-defined cytoplasm. They also showed papillary arcades surrounded and encased by relatively small ovoid to short spindle cells. Subsequent surgical excision confirmed the presence of malignant hemangiopericytoma (HP). Immunohistochemical studies on the histologic section using vimentin were strongly positive, consistent with HP. To the best of our knowledge, this is the second published report of FNA cellular features of malignant HP of the salivary gland. Besides delineating the FNA cellular features of HP of the salivary gland, the present case illustrates the value of using immunohistochemical approaches. Diagn. Cytopathol. 1999;21:398-401. Copyright 1999 Wiley-Liss, Inc.

Simulation of axisymmetric jets with a finite element Navier-Stokes solver and a multilevel VOF approach

NASA Astrophysics Data System (ADS)

Cervone, A.; Manservisi, S.; Scardovelli, R.

2010-09-01

A multilevel VOF approach has been coupled to an accurate finite element Navier-Stokes solver in axisymmetric geometry for the simulation of incompressible liquid jets with high density ratios. The representation of the color function over a fine grid has been introduced to reduce the discontinuity of the interface at the cell boundary. In the refined grid the automatic breakup and coalescence occur at a spatial scale much smaller than the coarse grid spacing. To reduce memory requirements, we have implemented on the fine grid a compact storage scheme which memorizes the color function data only in the mixed cells. The capillary force is computed by using the Laplace-Beltrami operator and a volumetric approach for the two principal curvatures. Several simulations of axisymmetric jets have been performed to show the accuracy and robustness of the proposed scheme.

Velocity dependence of biphasic flow structuration: steady-state and oscillating flow effects

NASA Astrophysics Data System (ADS)

Tore Tallakstad, Ken; Jankov, Mihailo; Løvoll, Grunde; Toussaint, Renaud; Jørgen Mâløy, Knut; Grude Flekkøy, Eirik; Schmittbuhl, Jean; Schäfer, Gerhard; Méheust, Yves; Arendt Knudsen, Henning

2010-05-01

We study various types of biphasic flows in quasi-two-dimensional transparent porous models. These flows imply a viscous wetting fluid, and a lowly viscous one. The models are transparent, allowing the displacement process and structure to be monitored in space and time. Three different aspects will be presented: 1. In stationary biphasic flows, we study the relationship between the macroscopic pressure drop (related to relative permeability) and the average flow rate, and how this arises from the cluster size distribution of the lowly viscous fluid [1]. 2. In drainage situations, we study how the geometry of the invader can be explained, and how it gives rise to apparent dynamic capillary effects. We show how these can be explained by viscous effects on evolving geometries of invading fluid [2]. 3. We study the impact of oscillating pressure fields superimposed to a background flow over the flow regimes patterns [3]. Steady-State Two-Phase Flow in Porous Media: Statistics and Transport Properties. First, in stationary flow with a control of the flux of both fluids, we show how the pressure drop depends on the flow rate. We will show that the dynamics is dominated by the interplay between a viscous pressure field from the wetting fluid and bubble transport of a less viscous, nonwetting phase. In contrast with more studied displacement front systems, steady-state flow is in equilibrium, statistically speaking. The corresponding theoretical simplicity allows us to explain a data collapse in the cluster size distribution of lowly viscous fluid in the system, as well as the relation |?P|∞√Ca--. This allows to explain so called relative permeability effects by the morphological changes of the cluster size distribution. Influence of viscous fingering on dynamic saturation-pressure curves in porous media. Next, we study drainage in such models, and investigate the relationship between the pressure field and the morphology of the invading fluid. This allows to model the impact of the saturation changes in the system over the pressure difference between the wetting and non wetting phase. We show that the so-called dynamic effects referred in the hydrology literature of experimentally measured capillary pressure curves might be explained by the combined effect of capillary pressure along the invasion front of the gaseous phase and pressure changes caused by viscous effects. A detailed study of the structure optically followed shows that the geometry of the invader is self-similar with two different behaviors at small and large scales: the structure corresponds to the ones of invasion percolation models at small scales (capillary fingering structures with fractal dimension D=1.83), whereas at large scales, viscous pressure drops dominate over the capillary threshold variations, and the structures are self-similar fingering structures with a fractal dimension corresponding to Dielectric Breakdown Models (variants of the DLA model), with D ≠ƒ 1.5. The cross-over scale is set by the scale at which capillary fluctuations are of the order of the viscous pressure drops. This leads physically to the fact that cross-over scale between the two fingering dimensions, goes like the inverse of the capillary number. This study utilizes these geometrical characteristics of the viscous fingers forming in dynamic drainage, to obtain a meaningfull scaling law for the saturation-pressure curve at finite speed, i.e. the so-called dynamic capillary pressure relations. We thus show how the micromechanical interplay between viscous and capillary forces leads to some pattern formation, which results in a general form of dynamic capillary pressure relations. By combining these detailed informations on the displacement structure with global measures of pressure, saturation and controlling the capillary number Ca, a scaling relation relating pressure, saturation, system size and capillary number is developed. By applying this scaling relation, pressure-saturation curves for a wide range of capillary numbers can be collapsed. Effects of pressure oscillations on drainage in an elastic porous medium: The effects of seismic stimulation on the flow of two immiscible fluids in an elastic synthetic porous medium is experimentally investigated. A wetting fluid is slowly evacuated from the medium, while a pressure oscillation is applied on the injected non-wetting fluid. The amplitude and frequency of the pressure oscillations as well as the evacuation speed are kept constant throughout an experiment. The resulting morphology of the invading structure is found to be strongly dependent on the interplay between the amplitude and the frequency of the applied pressure oscillations and the elasticity of the porous medium. Different combinations of these properties yield morphologically similar structures, allowing a classification of structures that is found to depend on a proposed dimensionless number. [1] Tallakstad, K.T., H.A. Knudsen, T. Ramstad, G. Løvoll, K.J. Maløy, R. Toussaint and E.G. Flekkøy , Steady-state two-phase flow in porous media: statistics and transport properties, Phys. Rev. Lett. 102, 074502 (2009). doi:10.1103/PhysRevLett.102.074502 [2] Løvoll, G., M. Jankov, K.J. Maløy, R. Toussaint, J. Schmittbuhl, G. Schaefer and Y. Ḿ eheust, Influence of viscous fingering on dynamic saturation-pressure curves in porous media, submitted to Transport In Porous Media, (2010) [3] Jankov, M., G. Løvoll, H.A. Knudsen, K.J. Maløy, R. Planet, R. Toussaint and E.G. Flekkøy; Effects of pressure oscillations on drainage in an elastic porous medium, Transport In Porous Media, in press (2010).

Longitudinal imaging of microvascular remodelling in proliferative diabetic retinopathy using adaptive optics scanning light ophthalmoscopy.

PubMed

Chui, Toco Yuen Ping; Pinhas, Alexander; Gan, Alexander; Razeen, Moataz; Shah, Nishit; Cheang, Eric; Liu, Chun L; Dubra, Alfredo; Rosen, Richard B

2016-05-01

To characterise longitudinal changes in the retinal microvasculature of type 2 diabetes mellitus (T2DM) as exemplified in a patient with proliferative diabetic retinopathy (PDR) using an adaptive optics scanning light ophthalmoscope (AOSLO). A 35-year-old T2DM patient with PDR treated with scatter pan-retinal photocoagulation at the inferior retina 1 day prior to initial AOSLO imaging along with a 24-year-old healthy control were imaged in this study. AOSLO vascular structural and perfusion maps were acquired at four visits over a 20-week period. Capillary diameter and microaneurysm area changes were measured on the AOSLO structural maps. Imaging repeatability was established using longitudinal imaging of microvasculature in the healthy control. Capillary occlusion and recanalisation, capillary dilatation, resolution of local retinal haemorrhage, capillary hairpin formation, capillary bend formation, microaneurysm formation, progression and regression were documented over time in a region 2° superior to the fovea in the PDR patient. An identical microvascular network with same capillary diameter was observed in the control subject over time. High-resolution serial AOSLO imaging enables in vivo observation of vasculopathic changes seen in diabetes mellitus. The implications of this methodology are significant, providing the opportunity for studying the dynamics of the pathological process, as well as the possibility of identifying highly sensitive and non-invasive biomarkers of end organ damage and response to treatment. © 2016 The Authors Ophthalmic & Physiological Optics © 2016 The College of Optometrists.

Direct Numerical Simulation of Low Capillary Number Pore Scale Flows

NASA Astrophysics Data System (ADS)

Esmaeilzadeh, S.; Soulaine, C.; Tchelepi, H.

2017-12-01

The arrangement of void spaces and the granular structure of a porous medium determines multiple macroscopic properties of the rock such as porosity, capillary pressure, and relative permeability. Therefore, it is important to study the microscopic structure of the reservoir pores and understand the dynamics of fluid displacements through them. One approach for doing this, is direct numerical simulation of pore-scale flow that requires a robust numerical tool for prediction of fluid dynamics and a detailed understanding of the physical processes occurring at the pore-scale. In pore scale flows with a low capillary number, Eulerian multiphase methods are well-known to produce additional vorticity close to the interface. This is mainly due to discretization errors which lead to an imbalance of capillary pressure and surface tension forces that causes unphysical spurious currents. At the pore scale, these spurious currents can become significantly stronger than the average velocity in the phases, and lead to unphysical displacement of the interface. In this work, we first investigate the capability of the algebraic Volume of Fluid (VOF) method in OpenFOAM for low capillary number pore scale flow simulations. Afterward, we compare VOF results with a Coupled Level-Set Volume of Fluid (CLSVOF) method and Iso-Advector method. It has been shown that the former one reduces the VOF's unphysical spurious currents in some cases, and both are known to capture interfaces sharper than VOF. As the conclusion, we will investigate that whether the use of CLSVOF or Iso-Advector will lead to less spurious velocities and more accurate results for capillary driven pore-scale multiphase flows or not. Keywords: Pore-scale multiphase flow, Capillary driven flows, Spurious currents, OpenFOAM

Gold nanoparticle incorporated inverse opal photonic crystal capillaries for optofluidic surface enhanced Raman spectroscopy.

PubMed

Zhao, Xiangwei; Xue, Jiangyang; Mu, Zhongde; Huang, Yin; Lu, Meng; Gu, Zhongze

2015-10-15

Novel transducers are needed for point of care testing (POCT) devices which aim at facile, sensitive and quick acquisition of health related information. Recent advances in optofluidics offer tremendous opportunities for biological/chemical analysis using extremely small sample volumes. This paper demonstrates nanostructured capillary tubes for surface enhanced Raman spectroscopy (SERS) analysis in a flow-through fashion. The capillary tube integrates the SERS sensor and the nanofluidic structure to synergistically offer sample delivery and analysis functions. Inside the capillary tube, inverse opal photonic crystal (IO PhC) was fabricated using the co-assembly approach to form nanoscale liquid pathways. In the nano-voids of the IO PhC, gold nanoparticles were in situ synthesized and functioned as the SERS hotspots. The advantages of the flow-through SERS sensor are multifold. The capillary effect facilities the sample delivery process, the nanofluidic channels boosts the interaction of analyte and gold nanoparticles, and the PhC structure strengthens the optical field near the SERS hotspots and results in enhanced SERS signals from analytes. As an exemplary demonstration, the sensor was used to measure creatinein spiked in artificial urine samples with detection limit of 0.9 mg/dL. Copyright © 2015 Elsevier B.V. All rights reserved.

Method for forming a chemical microreactor

DOEpatents

Morse, Jeffrey D [Martinez, CA; Jankowski, Alan [Livermore, CA

2009-05-19

Disclosed is a chemical microreactor that provides a means to generate hydrogen fuel from liquid sources such as ammonia, methanol, and butane through steam reforming processes when mixed with an appropriate amount of water. The microreactor contains capillary microchannels with integrated resistive heaters to facilitate the occurrence of catalytic steam reforming reactions. Two distinct embodiment styles are discussed. One embodiment style employs a packed catalyst capillary microchannel and at least one porous membrane. Another embodiment style employs a porous membrane with a large surface area or a porous membrane support structure containing a plurality of porous membranes having a large surface area in the aggregate, i.e., greater than about 1 m.sup.2/cm.sup.3. Various methods to form packed catalyst capillary microchannels, porous membranes and porous membrane support structures are also disclosed.

Laboratory-based observations of capillary barriers and preferential flow in layered snow

NASA Astrophysics Data System (ADS)

Avanzi, F.; Hirashima, H.; Yamaguchi, S.; Katsushima, T.; De Michele, C.

2015-12-01

Several evidences are nowadays available that show how the effects of capillary gradients and preferential flow on water transmission in snow may play a more important role than expected. To observe these processes and to contribute in their characterization, we performed observations on the development of capillary barriers and preferential flow patterns in layered snow during cold laboratory experiments. We considered three different layering (all characterized by a finer-over-coarser texture in grain size) and three different water input rates. Nine samples of layered snow were sieved in a cold laboratory, and subjected to a constant supply of dyed tracer. By means of visual inspection, horizontal sectioning and liquid water content measurements, the processes of ponding and preferential flow were characterized as a function of texture and water input rate. The dynamics of each sample were replicated using the multi-layer physically-based SNOWPACK model. Results show that capillary barriers and preferential flow are relevant processes ruling the speed of liquid water in stratified snow. Ponding is associated with peaks in LWC at the boundary between the two layers equal to ~ 33-36 vol. % when the upper layer is composed by fine snow (grain size smaller than 0.5 mm). The thickness of the ponding layer at the textural boundary is between 0 and 3 cm, depending on sample stratigraphy. Heterogeneity in water transmission increases with grain size, while we do not observe any clear dependency on water input rate. The extensive comparison between observed and simulated LWC profiles by SNOWPACK (using an approximation of Richards Equation) shows high performances by the model in estimating the LWC peak over the boundary, while water speed in snow is underestimated by the chosen water transport scheme.

Impact of groundwater capillary rises as lower boundary conditions for soil moisture in a land surface model

NASA Astrophysics Data System (ADS)

Vergnes, Jean-Pierre; Decharme, Bertrand; Habets, Florence

2014-05-01

Groundwater is a key component of the global hydrological cycle. It sustains base flow in humid climate while it receives seepage in arid region. Moreover, groundwater influences soil moisture through water capillary rise into the soil and potentially affects the energy and water budget between the land surface and the atmosphere. Despite its importance, most global climate models do not account for groundwater and their possible interaction with both the surface hydrology and the overlying atmosphere. This study assesses the impact of capillary rise from shallow groundwater on the simulated water budget over France. The groundwater scheme implemented in the Total Runoff Integrated Pathways (TRIP) river routing model in a previous study is coupled with the Interaction between Soil Biosphere Atmosphere (ISBA) land surface model. In this coupling, the simulated water table depth acts as the lower boundary condition for the soil moisture diffusivity equation. An original parameterization accounting for the subgrid elevation inside each grid cell is proposed in order to compute this fully-coupled soil lower boundary condition. Simulations are performed at high (1/12°) and low (0.5°) resolutions and evaluated over the 1989-2009 period. Compared to a free-drain experiment, upward capillary fluxes at the bottom of soil increase the mean annual evapotranspiration simulated over the aquifer domain by 3.12 % and 1.54 % at fine and low resolutions respectively. This process logically induces a decrease of the simulated recharge from ISBA to the aquifers and contributes to enhance the soil moisture memory. The simulated water table depths are then lowered, which induces a slight decrease of the simulated mean annual river discharges. However, the fully-coupled simulations compare well with river discharge and water table depth observations which confirms the relevance of the coupling formalism.

Atmospheric pressure chemical ionization of explosives using alternating current corona discharge ion source.

PubMed

Usmanov, D T; Chen, L C; Yu, Z; Yamabe, S; Sakaki, S; Hiraoka, K

2015-04-01

The high-sensitive detection of explosives is of great importance for social security and safety. In this work, the ion source for atmospheric pressure chemical ionization/mass spectrometry using alternating current corona discharge was newly designed for the analysis of explosives. An electromolded fine capillary with 115 µm inner diameter and 12 mm long was used for the inlet of the mass spectrometer. The flow rate of air through this capillary was 41 ml/min. Stable corona discharge could be maintained with the position of the discharge needle tip as close as 1 mm to the inlet capillary without causing the arc discharge. Explosives dissolved in 0.5 µl methanol were injected to the ion source. The limits of detection for five explosives with 50 pg or lower were achieved. In the ion/molecule reactions of trinitrotoluene (TNT), the discharge products of NOx (-) (x = 2,3), O3 and HNO3 originating from plasma-excited air were suggested to contribute to the formation of [TNT - H](-) (m/z 226), [TNT - NO](-) (m/z 197) and [TNT - NO + HNO3 ](-) (m/z 260), respectively. Formation processes of these ions were traced by density functional theory calculations. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

Translocation and potential neurological effects of fine and ultrafine particles a critical update

PubMed Central

Peters, Annette; Veronesi, Bellina; Calderón-Garcidueñas, Lilian; Gehr, Peter; Chen, Lung Chi; Geiser, Marianne; Reed, William; Rothen-Rutishauser, Barbara; Schürch, Samuel; Schulz, Holger

2006-01-01

Particulate air pollution has been associated with respiratory and cardiovascular disease. Evidence for cardiovascular and neurodegenerative effects of ambient particles was reviewed as part of a workshop. The purpose of this critical update is to summarize the evidence presented for the mechanisms involved in the translocation of particles from the lung to other organs and to highlight the potential of particles to cause neurodegenerative effects. Fine and ultrafine particles, after deposition on the surfactant film at the air-liquid interface, are displaced by surface forces exerted on them by surfactant film and may then interact with primary target cells upon this displacement. Ultrafine and fine particles can then penetrate through the different tissue compartments of the lungs and eventually reach the capillaries and circulating cells or constituents, e.g. erythrocytes. These particles are then translocated by the circulation to other organs including the liver, the spleen, the kidneys, the heart and the brain, where they may be deposited. It remains to be shown by which mechanisms ultrafine particles penetrate through pulmonary tissue and enter capillaries. In addition to translocation of ultrafine particles through the tissue, fine and coarse particles may be phagocytized by macrophages and dendritic cells which may carry the particles to lymph nodes in the lung or to those closely associated with the lungs. There is the potential for neurodegenerative consequence of particle entry to the brain. Histological evidence of neurodegeneration has been reported in both canine and human brains exposed to high ambient PM levels, suggesting the potential for neurotoxic consequences of PM-CNS entry. PM mediated damage may be caused by the oxidative stress pathway. Thus, oxidative stress due to nutrition, age, genetics among others may increase the susceptibility for neurodegenerative diseases. The relationship between PM exposure and CNS degeneration can also be detected under controlled experimental conditions. Transgenic mice (Apo E -/-), known to have high base line levels of oxidative stress, were exposed by inhalation to well characterized, concentrated ambient air pollution. Morphometric analysis of the CNS indicated unequivocally that the brain is a critical target for PM exposure and implicated oxidative stress as a predisposing factor that links PM exposure and susceptibility to neurodegeneration. Together, these data present evidence for potential translocation of ambient particles on organs distant from the lung and the neurodegenerative consequences of exposure to air pollutants. PMID:16961926

Translocation and potential neurological effects of fine and ultrafine particles a critical update.

PubMed

Peters, Annette; Veronesi, Bellina; Calderón-Garcidueñas, Lilian; Gehr, Peter; Chen, Lung Chi; Geiser, Marianne; Reed, William; Rothen-Rutishauser, Barbara; Schürch, Samuel; Schulz, Holger

2006-09-08

Particulate air pollution has been associated with respiratory and cardiovascular disease. Evidence for cardiovascular and neurodegenerative effects of ambient particles was reviewed as part of a workshop. The purpose of this critical update is to summarize the evidence presented for the mechanisms involved in the translocation of particles from the lung to other organs and to highlight the potential of particles to cause neurodegenerative effects. Fine and ultrafine particles, after deposition on the surfactant film at the air-liquid interface, are displaced by surface forces exerted on them by surfactant film and may then interact with primary target cells upon this displacement. Ultrafine and fine particles can then penetrate through the different tissue compartments of the lungs and eventually reach the capillaries and circulating cells or constituents, e.g. erythrocytes. These particles are then translocated by the circulation to other organs including the liver, the spleen, the kidneys, the heart and the brain, where they may be deposited. It remains to be shown by which mechanisms ultrafine particles penetrate through pulmonary tissue and enter capillaries. In addition to translocation of ultrafine particles through the tissue, fine and coarse particles may be phagocytized by macrophages and dendritic cells which may carry the particles to lymph nodes in the lung or to those closely associated with the lungs. There is the potential for neurodegenerative consequence of particle entry to the brain. Histological evidence of neurodegeneration has been reported in both canine and human brains exposed to high ambient PM levels, suggesting the potential for neurotoxic consequences of PM-CNS entry. PM mediated damage may be caused by the oxidative stress pathway. Thus, oxidative stress due to nutrition, age, genetics among others may increase the susceptibility for neurodegenerative diseases. The relationship between PM exposure and CNS degeneration can also be detected under controlled experimental conditions. Transgenic mice (Apo E -/-), known to have high base line levels of oxidative stress, were exposed by inhalation to well characterized, concentrated ambient air pollution. Morphometric analysis of the CNS indicated unequivocally that the brain is a critical target for PM exposure and implicated oxidative stress as a predisposing factor that links PM exposure and susceptibility to neurodegeneration. Together, these data present evidence for potential translocation of ambient particles on organs distant from the lung and the neurodegenerative consequences of exposure to air pollutants.

ANALYSIS OF GLYCANS DERIVED FROM GLYCOCONJUGATES BY CAPILLARY ELECTROPHORESIS-MASS SPECTROMETRY

PubMed Central

Mechref, Yehia

2012-01-01

The high structural variation of glycan derived from glycoconjugates, which substantially increases with the molecular size of a protein, contributes to the complexity of glycosylation patterns commonly associated with glycoconjugates. In the case of glycoproteins, such variation originates from the multiple glycosylation sites of proteins and the number of glycan structures associated with each site (microheterogeneity). The ability to comprehensively characterize highly complex mixture of glycans has been analytically stimulating and challenging. Although the most powerful mass spectrometric (MS) and tandem MS techniques are capable of providing a wealth of structural information, they are still not able to readily identify isomeric glycan structures without high order tandem MS (MSn). The analysis of isomeric glycan structures has been attained using several separation methods, including high-pH anion exchange chromatography (HPAEC), hydrophilic interaction chromatography (HILIC) and gas chromatography (GC). However, capillary electrophoresis (CE) and microfluidics capillary electrophoresis (MCE) offer high separation efficiency and resolutions, allowing the separation of closely related glycan structures. Therefore, interfacing CE and MCE to MS is a powerful analytical approach, allowing potentially comprehensive and sensitive analysis of complex glycan samples. This review describes and discusses the utility of different CE and MCE approaches in the structural characterization of glycoproteins and the feasibility of interfacing these approaches to mass spectrometry. PMID:22180203

Surface Chemistry and Structural Effects in the Stress Corrosion of Glass and Ceramic Materials.

DTIC Science & Technology

1986-03-31

capillary can be improved for (GC)2 by passing S sulfur dioxide or difluoroethane through the preform and capillary during the fabrication 27 . The...hydration resistance of the glass surface. In fact, it was recently shown that the combined use of sulfur dioxide and * difluoroethane could further

Percolation study for the capillary ascent of a liquid through a granular soil

NASA Astrophysics Data System (ADS)

Cárdenas-Barrantes, Manuel Antonio; Muñoz, José Daniel; Araujo, Nuno Machado

2017-06-01

Capillary rise plays a crucial role in the construction of road embankments in flood zones, where hydrophobic compounds are added to the soil to suppress the rising of water and avoid possible damage of the pavement. Water rises through liquid bridges, menisci and trimers, whose width and connectivity depends on the maximal half-length λ of the capillary bridges among grains. Low λs generate a disconnect structure, with small clusters everywhere. On the contrary, for high λ, create a percolating cluster of trimers and enclosed volumes that form a natural path for capillary rise. Hereby, we study the percolation transition of this geometric structure as a function of λ on a granular media of monodisperse spheres in a random close packing. We determine both the percolating threshold λc = (0.049 ± 0.004)R (with R the radius of the granular spheres), and the critical exponent of the correlation length v = 0.830 ± 0.051, suggesting that the percolation transition falls into the universality class of ordinary percolation.

The combination of electrospray and flow focusing

NASA Astrophysics Data System (ADS)

Gañán-Calvo, Alfonso M.; López-Herrera, José M.; Riesco-Chueca, Pascual

2006-11-01

An ultra-fine liquid atomization procedure combining the advantages of electrospray and flow focusing is presented. Both techniques are known to produce strikingly small and steady liquid micro-jets issuing from menisci held by capillary forces. Such menisci take the form of a cusp-like drop attached to the feeding tube (flow focusing: FF) or a Taylor cone (electrospray: ES). The issuing micro-jets are forced or ‘sucked’ from the parent meniscus either by pressure or electrohydrodynamic forces. Subsequent capillary breakup of the jet leads to fine sprays of remarkable quality. Here we describe the joint effect of pressurization and electrification in a flow focusing device, and the subsequent coupling of both ES and FF phenomena. For any given liquid and flow rate, the combined procedure gives rise to significantly smaller droplet sizes than observed in any of the source techniques. The co-flowing gas stream removes space charges; in addition, the perforated plate facing the feed tube provides an electric barrier, shielding the jet-meniscus or ‘production’ area from the spray or ‘product’ area. As a result, space charges and electrified droplets are removed from the production area, thus avoiding the ambient electric saturation which becomes a limiting factor in ES-spraying: a significantly enhanced spraying stability ensues, with a much wider operation range than FF or ES. Other unexpected outcomes from the combination are also shown. A theoretical model is developed to predict the emitted droplet size: a first integral of the momentum equation yielding a generalized Bernoulli equation, and an explicit approximation for the jet diameter and droplet size, accurate within a broad parametrical band.

Blood Perfusion in Microfluidic Models of Pulmonary Capillary Networks: Role of Geometry and Hematocrit

NASA Astrophysics Data System (ADS)

Stauber, Hagit; Waisman, Dan; Sznitman, Josue; Technion-IIT Team; Department of Neonatology Carmel Medical Center; Faculty of Medicine-Technion IIT Collaboration

2015-11-01

Microfluidic platforms are increasingly used to study blood microflows at true physiological scale due to their ability to overcome manufacturing obstacle of complex anatomical morphologies, such as the organ-specific architectures of the microcirculation. In the present work, we utilize microfluidic platforms to devise in vitro models of the underlying pulmonary capillary networks (PCN), where capillary lengths and diameters are similar to the size of RBCs (~ 5-10 μm). To better understand flow characteristics and dispersion of red blood cells (RBCs) in PCNs, we have designed microfluidic models of alveolar capillary beds inspired by the seminal ``sheet flow'' model of Fung and Sobin (1969). Our microfluidic PCNs feature confined arrays of staggered pillars with diameters of ~ 5,7 and 10 μm, mimicking the dense structure of pulmonary capillary meshes. The devices are perfused with suspensions of RBCs at varying hematocrit levels under different flow rates. Whole-field velocity patterns using micro-PIV and single-cell tracking using PTV are obtained with fluorescently-labelled RBCs and discussed. Our experiments deliver a real-scale quantitative description of RBC perfusion characteristics across the pulmonary capillary microcirculation.

On-line DNA analysis system with rapid thermal cycling

DOEpatents

Swerdlow, Harold P.; Wittwer, Carl T.

1999-01-01

An apparatus particularly suited for subjecting biological samples to any necessary sample preparation tasks, subjecting the sample to rapid thermal cycling, and then subjecting the sample to subsequent on-line analysis using one or more of a number of analytical techniques. The apparatus includes a chromatography device including an injection means, a chromatography pump, and a chromatography column. In addition, the apparatus also contains a capillary electrophoresis device consisting of a capillary electrophoresis column with an inlet and outlet end, a means of injection, and means of applying a high voltage to cause the differential migration of species of interest through the capillary column. Effluent from the liquid chromatography column passes over the inlet end of the capillary electrophoresis column through a tee structure and when the loading of the capillary electrophoresis column is desired, a voltage supply is activated at a precise voltage and polarity over a specific duration to cause sample species to be diverted from the flowing stream to the capillary electrophoresis column. A laser induced fluorescence detector preferably is used to analyze the products separated while in the electrophoresis column.

On-line DNA analysis system with rapid thermal cycling

DOEpatents

Swerdlow, H.P.; Wittwer, C.T.

1999-08-10

This application describes an apparatus particularly suited for subjecting biological samples to any necessary sample preparation tasks, subjecting the sample to rapid thermal cycling, and then subjecting the sample to subsequent on-line analysis using one or more of a number of analytical techniques. The apparatus includes a chromatography device including an injection means, a chromatography pump, and a chromatography column. In addition, the apparatus also contains a capillary electrophoresis device consisting of a capillary electrophoresis column with an inlet and outlet end, a means of injection, and means of applying a high voltage to cause the differential migration of species of interest through the capillary column. Effluent from the liquid chromatography column passes over the inlet end of the capillary electrophoresis column through a tee structure and when the loading of the capillary electrophoresis column is desired, a voltage supply is activated at a precise voltage and polarity over a specific duration to cause sample species to be diverted from the flowing stream to the capillary electrophoresis column. A laser induced fluorescence detector preferably is used to analyze the products separated while in the electrophoresis column. 6 figs.

Proof Of Concept of Integrated Load Measurement in 3D Printed Structures

DOE PAGES

Hinderdael, Michael; Strantza, Maria; De Baere, Dieter; ...

2017-02-09

Currently, research on structural health monitoring systems is focused on direct integration of the system into a component or structure. The latter results in a so-called smart structure. One example of a smart structure is a component with integrated strain sensing for continuous load monitoring. Additive manufacturing, or 3D printing, now also enables such integration of functions inside components. As a proof-of-concept, the Fused Deposition Modeling (FDM) technique was used to integrate a strain sensing element inside polymer (ABS) tensile test samples. The strain sensing element consisted of a closed capillary filled with a fluid and connected to an externallymore » mounted pressure sensor. The volumetric deformation of the integrated capillary resulted in pressure changes in the fluid. The obtained pressure measurements during tensile testing are reported in this paper and compared to state-of-the-art extensometer measurements. The sensitivity of the 3D printed pressure-based strain sensor is primarily a function of the compressibility of the capillary fluid. Air- and watertightness are of critical importance for the proper functioning of the 3D printed pressure-based strain sensor. Therefore, the best after-treatment procedure was selected on basis of a comparative analysis. The obtained pressure measurements are linear with respect to the extensometer readings, and the uncertainty on the strain measurement of a capillary filled with water (incompressible fluid) is ±3.1 µstrain, which is approximately three times less sensitive than conventional strain gauges (±1 µstrain), but 32 times more sensitive than the same sensor based on air (compressible fluid) (±101 µstrain).« less

Proof Of Concept of Integrated Load Measurement in 3D Printed Structures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hinderdael, Michael; Strantza, Maria; De Baere, Dieter

Currently, research on structural health monitoring systems is focused on direct integration of the system into a component or structure. The latter results in a so-called smart structure. One example of a smart structure is a component with integrated strain sensing for continuous load monitoring. Additive manufacturing, or 3D printing, now also enables such integration of functions inside components. As a proof-of-concept, the Fused Deposition Modeling (FDM) technique was used to integrate a strain sensing element inside polymer (ABS) tensile test samples. The strain sensing element consisted of a closed capillary filled with a fluid and connected to an externallymore » mounted pressure sensor. The volumetric deformation of the integrated capillary resulted in pressure changes in the fluid. The obtained pressure measurements during tensile testing are reported in this paper and compared to state-of-the-art extensometer measurements. The sensitivity of the 3D printed pressure-based strain sensor is primarily a function of the compressibility of the capillary fluid. Air- and watertightness are of critical importance for the proper functioning of the 3D printed pressure-based strain sensor. Therefore, the best after-treatment procedure was selected on basis of a comparative analysis. The obtained pressure measurements are linear with respect to the extensometer readings, and the uncertainty on the strain measurement of a capillary filled with water (incompressible fluid) is ±3.1 µstrain, which is approximately three times less sensitive than conventional strain gauges (±1 µstrain), but 32 times more sensitive than the same sensor based on air (compressible fluid) (±101 µstrain).« less

Proof of Concept of Integrated Load Measurement in 3D Printed Structures

PubMed Central

Hinderdael, Michaël; Jardon, Zoé; Lison, Margot; De Baere, Dieter; Devesse, Wim; Strantza, Maria; Guillaume, Patrick

2017-01-01

Currently, research on structural health monitoring systems is focused on direct integration of the system into a component or structure. The latter results in a so-called smart structure. One example of a smart structure is a component with integrated strain sensing for continuous load monitoring. Additive manufacturing, or 3D printing, now also enables such integration of functions inside components. As a proof-of-concept, the Fused Deposition Modeling (FDM) technique was used to integrate a strain sensing element inside polymer (ABS) tensile test samples. The strain sensing element consisted of a closed capillary filled with a fluid and connected to an externally mounted pressure sensor. The volumetric deformation of the integrated capillary resulted in pressure changes in the fluid. The obtained pressure measurements during tensile testing are reported in this paper and compared to state-of-the-art extensometer measurements. The sensitivity of the 3D printed pressure-based strain sensor is primarily a function of the compressibility of the capillary fluid. Air- and watertightness are of critical importance for the proper functioning of the 3D printed pressure-based strain sensor. Therefore, the best after-treatment procedure was selected on basis of a comparative analysis. The obtained pressure measurements are linear with respect to the extensometer readings, and the uncertainty on the strain measurement of a capillary filled with water (incompressible fluid) is ±3.1 µstrain, which is approximately three times less sensitive than conventional strain gauges (±1 µstrain), but 32 times more sensitive than the same sensor based on air (compressible fluid) (±101 µstrain). PMID:28208779

Evaluation of capillary reinforced composites

NASA Technical Reports Server (NTRS)

Cahill, J. E.; Halase, J. F.; South, W. K.; Stoffer, L. J.

1985-01-01

Anti-icing of the inlet of jet engines is generally performed with high pressure heated air that is directed forward from the compressor through a series of pipes to various manifolds located near the structures to be anti-iced. From these manifolds, the air is directed to all flowpath surfaces that may be susceptible to ice formation. There the anti-icing function may be performed by either heat conduction or film heating. Unfortunately, the prospect of utilizing lighweight, high strength composites for inlet structures of jet engines has been frustrated by the low transverse thermal conductivity of such materials. It was the objective of this program to develop an advanced materials and design concept for anti-icing composite structures. The concept that was evaluated used capillary glass tubes embedded on the surface of a composite structure with heated air ducted through the tubes. An analytical computer program was developed to predict the anti-icing performance of such tubes and a test program was conducted to demonstrate actual performance of this system. Test data and analytical code results were in excellent agreement. Both indicate feasibility of using capillary tubes for surface heating as a means for composite engine structures to combat ice accumulation.

Effect of antioxidant therapy with dl-alpha-tocopherol on cardiovascular structure in experimental renal failure.

PubMed

Amann, Kerstin; Törnig, Johannes; Buzello, Mareike; Kuhlmann, Alexander; Gross, Marie-Luise; Adamczak, Marcin; Buzello, Moriz; Ritz, Eberhard

2002-09-01

Chronic renal failure is characterized by remodeling of the structure of the heart and the vasculature, for example, left ventricular hypertrophy, myocardial fibrosis, capillary/myocyte mismatch, as well as thickening of intramyocardial arteries and of peripheral arteries and veins. Furthermore, uremia is a state of increased oxygen stress. It was the purpose of this study to examine whether these findings are interrelated. To investigate whether antioxidative therapy with dl-alpha-tocopherol (Toco; vitamin E) interferes with the development of abnormal cardiovascular structure in experimental renal failure, 28 male Sprague-Dawley rats were subjected to partial renal ablation (subtotal nephrectomy, SNX) or to sham operation (sham). SNX were either left untreated or received the antioxidant Toco (2 x 1500 IE/kg BW/week in the pellets). Blood pressure was measured using tail plethysmography. The experiment was terminated after 12 weeks. Heart and left ventricular weight were determined and the following parameters were measured using morphometry and stereology: volume densities of cardiomyocytes, capillaries and non-vascular interstitium; length density and total length of cardiac capillaries, wall thickness of intramyocardial arterioles and of the aorta. Systolic blood pressure and body weight were comparable in all groups. Treatment with Toco led to significantly increased plasma concentrations of Toco. Left ventricular weight and wall thickness of intramyocardial arteries were significantly higher in both SNX groups compared to sham controls. Volume density of the cardiac interstitial tissue was significantly higher in untreated SNX than in Toco treated SNX and sham control rats. Length density of capillaries was significantly lower in untreated SNX than in control rats; however, the values were significantly higher, and even higher than in sham controls, when SNX were treated with Toco. Treatment with the antioxidant dl-alpha-tocopherol prevented cardiomyocyte/capillary mismatch, and to some extent also myocardial fibrosis in rats with renal failure. The results point to a role of oxidative stress in the genesis of myocardial interstitial fibrosis and capillary deficit of the heart.

Automated structure and flow measurement - a promising tool in nailfold capillaroscopy.

PubMed

Berks, Michael; Dinsdale, Graham; Murray, Andrea; Moore, Tonia; Manning, Joanne; Taylor, Chris; Herrick, Ariane L

2018-07-01

Despite increasing interest in nailfold capillaroscopy, objective measures of capillary structure and blood flow have been little studied. We aimed to test the hypothesis that structural measurements, capillary flow, and a combined measure have the predictive power to separate patients with systemic sclerosis (SSc) from those with primary Raynaud's phenomenon (PRP) and healthy controls (HC). 50 patients with SSc, 12 with PRP, and 50 HC were imaged using a novel capillaroscopy system that generates high-quality nailfold images and provides fully-automated measurements of capillary structure and blood flow (capillary density, mean width, maximum width, shape score, derangement and mean flow velocity). Population statistics summarise the differences between the three groups. Areas under ROC curves (A Z ) were used to measure classification accuracy when assigning individuals to SSc and HC/PRP groups. Statistically significant differences in group means were found between patients with SSc and both HC and patients with PRP, for all measurements, e.g. mean width (μm) ± SE: 15.0 ± 0.71, 12.7 ± 0.74 and 11.8 ± 0.23 for SSc, PRP and HC respectively. Combining the five structural measurements gave better classification (A Z  = 0.919 ± 0.026) than the best single measurement (mean width, A Z  = 0.874 ± 0.043), whilst adding flow further improved classification (A Z  = 0.930 ± 0.024). Structural and blood flow measurements are both able to distinguish patients with SSc from those with PRP/HC. Importantly, these hold promise as clinical trial outcome measures for treatments aimed at improving finger blood flow or microvascular remodelling. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

Deep Retinal Capillary Nonperfusion Is Associated With Photoreceptor Disruption in Diabetic Macular Ischemia.

PubMed

Scarinci, Fabio; Nesper, Peter L; Fawzi, Amani A

2016-08-01

To report outer retinal structural changes associated with macular capillary nonperfusion at the level of deep capillary plexus (DCP) in diabetic patients. Prospective observational cross-sectional study. The study included 14 eyes of 10 patients who were diagnosed as having diabetic retinopathy. To study the outer retina and localize areas of capillary nonperfusion at the superficial (SCP) or DCP, we used the spectral-domain optical coherence tomography (SDOCT) device (RTVue-XR Avanti; Optovue Inc, Fremont, California, USA) with split-spectrum amplitude-decorrelation angiography (SSADA) software for optical coherence tomography angiography (OCTA). Two independent masked graders (F.S. and A.A.F.) qualitatively evaluated SDOCT scans as either normal or having outer retina disruption. The angiographic images were examined to define the presence and location of capillary nonperfusion. Eight eyes showed outer retinal disruption on SDOCT that co-localized to areas of enlarged foveal avascular zone, areas of no flow between capillaries, and capillary nonperfusion of the DCP. Six eyes without outer retinal changes on SDOCT showed robust perfusion of the DCP. Using OCTA, this study shows that macular photoreceptor disruption on SDOCT in patients with diabetic retinopathy corresponds to areas of capillary nonperfusion at the level of the DCP. This is important in highlighting the contribution of the DCP to the oxygen requirements of the photoreceptors as well as the outer retina in diabetic macular ischemia. Copyright © 2016 Elsevier Inc. All rights reserved.

An Apparent Deficiency of Lymphatic Capillaries in the Islets of Langerhans in the Human Pancreas.

PubMed

Korsgren, Erik; Korsgren, Olle

2016-04-01

The lymphatic system is crucial for efficient immune surveillance and for the maintenance of a physiological pressure in the interstitial space. Even so, almost no information is available concerning the lymph drainage of the islets of Langerhans in the human pancreas. Immunohistochemical staining allowed us to distinguish lymphatic capillaries from blood capillaries. Almost no lymphatic capillaries were found within the islets in pancreatic biopsy specimens from subjects without diabetes or from subjects with type 1 or type 2 diabetes. Lymphatic capillaries were, however, found at the islet-exocrine interface, frequently located along blood capillaries and other fibrotic structures within or close to the islet capsule. Lymphatic capillaries were regularly found in the exocrine pancreas, with small lymphatic vessels located close to and around acini. Larger collecting lymphatic vessels were located in fibrotic septa between the exocrine lobules and adjacent to the ductal system of the pancreas. In summary, we report a pronounced deficiency of lymphatic capillaries in human islets, a finding with implications for immune surveillance and the regulation of interstitial fluid transport in the endocrine pancreas as well as for the pathophysiology of both type 1 and type 2 diabetes. © 2016 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered.

Combined effect of capillary barrier and layered slope on water, solute and nanoparticle transfer in an unsaturated soil at lysimeter scale.

PubMed

Prédélus, Dieuseul; Coutinho, Artur Paiva; Lassabatere, Laurent; Bien, Le Binh; Winiarski, Thierry; Angulo-Jaramillo, Rafael

2015-10-01

It is well recognized that colloidal nanoparticles are highly mobile in soils and can facilitate the transport of contaminants through the vadose zone. This work presents the combined effect of the capillary barrier and soil layer slope on the transport of water, bromide and nanoparticles through an unsaturated soil. Experiments were performed in a lysimeter (1×1×1.6m(3)) called LUGH (Lysimeter for Urban Groundwater Hydrology). The LUGH has 15 outputs that identify the temporal and spatial evolution of water flow, solute flux and nanoparticles in relation to the soil surface conditions and the 3D system configuration. Two different soil structures were set up in the lysimeter. The first structure comprises a layer of sand (0-0.2cm, in diameter) 35cm thick placed horizontally above a layer of bimodal mixture also 35cm thick to create a capillary barrier at the interface between the sand and bimodal material. The bimodal material is composed of a mixture 50% by weight of sand and gravel (0.4-1.1cm, in diameter). The second structure, using the same amount of sand and bimodal mixture as the first structure represents an interface with a 25% slope. A 3D numerical model based on Richards equation for flow and the convection dispersion equations coupled with a mechanical module for nanoparticle trapping was developed. The results showed that under the effect of the capillary barrier, water accumulated at the interface of the two materials. The sloped structure deflects flow in contrast to the structure with zero slope. Approximately 80% of nanoparticles are retained in the lysimeter, with a greater retention at the interface of two materials. Finally, the model makes a good reproduction of physical mechanisms observed and appears to be a useful tool for identifying key processes leading to a better understanding of the effect of capillary barrier on nanoparticle transfer in an unsaturated heterogeneous soil. Copyright © 2015 Elsevier B.V. All rights reserved.

Capillary Assembly of Colloids: Interactions on Planar and Curved Interfaces

NASA Astrophysics Data System (ADS)

Liu, Iris B.; Sharifi-Mood, Nima; Stebe, Kathleen J.

2018-03-01

In directed assembly, small building blocks are assembled into an organized structure under the influence of guiding fields. Capillary interactions provide a versatile route for structure formation. Colloids adsorbed on fluid interfaces distort the interface, which creates an associated energy field. When neighboring distortions overlap, colloids interact to minimize interfacial area. Contact line pinning, particle shape, and surface chemistry play important roles in structure formation. Interface curvature acts like an external field; particles migrate and assemble in patterns dictated by curvature gradients. We review basic analysis and recent findings in this rapidly evolving literature. Understanding the roles of assembly is essential for tuning the mechanical, physical, and optical properties of the structure.

Method and apparatus for optimized sampling of volatilizable target substances

DOEpatents

Lindgren, Eric R.; Phelan, James M.

2002-01-01

An apparatus for capturing, from gases such as soil gas, target analytes. Target analytes may include emanations from explosive materials or from residues of explosive materials. The apparatus employs principles of sorption common to solid phase microextraction, and is best used in conjunction with analysis means such as a gas chromatograph. To sorb target analytes, the apparatus functions using various sorptive structures to capture target analyte. Depending upon the embodiment, those structures may include 1) a conventional solid-phase microextraction (SPME) fiber, 2) a SPME fiber suspended in a capillary tube (with means provided for moving gases through the capillary tube so that the gases come into close proximity to the suspended fiber), and 3) a capillary tube including an interior surface on which sorptive material (similar to that on the surface of a SPME fiber) is supported (along with means for moving gases through the capillary tube so that the gases come into close proximity to the sorptive material). In one disclosed embodiment, at least one such sorptive structure is associated with an enclosure including an opening in communication with the surface of a soil region potentially contaminated with buried explosive material such as unexploded ordnance. Emanations from explosive materials can pass into and accumulate in the enclosure where they are sorbed by the sorptive structures. Also disclosed is the use of heating means such as microwave horns to drive target analytes into the soil gas from solid and liquid phase components of the soil.

Characterization for capillary barriers effects in a sand box test using time-lapsed GPR measurements

NASA Astrophysics Data System (ADS)

Kuroda, S.; Ishii, N.; Morii, T.

2017-12-01

Capillary barriers have been known as the method to protect subsurface regions against infiltration from soil surface. It is caused by essentially heterogeneous structure in permeability or soil physical property and produce non-uniform infiltration process then, in order to estimate the actual situation of the capillary barrier effect, the site-characterization with imaging technique like geophysical prospecting is effective. In this study, we examine the applicability of GPR to characterization for capillary barriers. We built a sand box with 90x340x90cm in which a thin high-permeable gravel layer was embedded as a capillary barrier. We conducted an infiltration test in the sand box using porous tube array for irrigation. It is expected to lead to non-uniform flow of soil water induced by capillary barrier effects. We monitored this process by various types of GPR measurements, including time-lapsed common offset profiling (COP) with multi- frequency antenna and transmission measurements like cross-borehole radar. At first, we conducted GPR common-offset survey. It could show the depth of capillary barrier in sand box. After that we conducted the infiltration test and GPR monitoring for infiltration process. GPR profiles can detect the wetting front and estimate water content change in the soil layer above the capillary barrier. From spatial change in these results we can estimate the effect of capillary barrier and the zone where the break through occur or not. Based on these results, we will discuss the applicability of GPR for monitoring the phenomena around the capillary barrier of soil. At first, we conducted GPR common-offset survey. It could show the depth of capillary barrier in sand box. After that we conducted the infiltration test and GPR monitoring for infiltration process. GPR profiles can detect the wetting front and estimate water content change in the soil layer above the capillary barrier. From spatial change in these results we can estimate the effect of capillary barrier and the zone where the break through occur. Based on these results, we will discuss the applicability of GPR for monitoring the phenomena around the capillary barrier of soil.

A study on the performance of concrete containing recycled aggregates and ceramic as materials replacement

NASA Astrophysics Data System (ADS)

Azmi, N. B.; Khalid, F. S.; Irwan, J. M.; Anting, N.; Mazenan, P. N.

2017-11-01

Natural fine aggregate materials are commonly used in development and commercial construction in Malaysia. In fact, concrete production was increased as linear with the growing Malaysia economy. However, an issue was production of concrete was to locate adequate sources of natural fine aggregates. There lot of studies have been conducted in order to replace the fine aggregate in which natural fine aggregate replace with the waste material in concrete preparation. Therefore, this study aims to utilize the Recycled Concrete Aggregate (RCA) and ceramic waste which has great potential to replace the natural aggregate in concrete mix with different type of method, admixture, and parameters. This research were focused on compressive strength and water absorption test to determine the optimum mix ratio of concrete mix. The concrete aggregate was chosen due to improvement capillary bonding mechanisms and ceramic presented similar strength compared to the conventional concrete using natural aggregate. Percent of replacement have been used in this study was at 25%, 35% and 45% of the RCA and 5%, 10% and 15% for ceramic, respectively. Furthermore, this research was conduct to find the optimum percentage of aggregate replacement, using water-cement ratio of 0.55 with concrete grade 25/30. The best percentage of replacement was the RCA35% C15% with the compressive strength of 34.72 MPa and the water absorption was satisfied.

Comprehensive characterisation of atmospheric aerosols in Budapest, Hungary: physicochemical properties of inorganic species

NASA Astrophysics Data System (ADS)

Salma, Imre; Maenhaut, Willy; Zemplén-Papp, Éva; Záray, Gyula

As part of an air pollution project in Budapest, aerosol samples were collected by stacked filter units and cascade impactors at an urban background site, two downtown sites, and within a road tunnel in field campaigns conducted in 1996, 1998 and 1999. Some criteria pollutants were also measured at one of the downtown sites. The aerosol samples were analysed by one or more of the following methods: instrumental neutron activation analysis, particle-induced X-ray emission analysis, a light reflection technique, gravimetry, thermal profiling carbon analysis and capillary electrophoresis. The quantities measured or derived include atmospheric concentrations of elements (from Na to U), of particulate matter, of black and elemental carbon, and total carbonaceous fraction, of some ionic species (e.g., nitrate and sulphate) in the fine ( <2 μm equivalent aerodynamic diameter, EAD) or in both coarse (10- 2 μm EAD) and fine size fractions, atmospheric concentrations of NO, NO 2, SO 2, CO and total suspended particulate matter, and meteorological parameters. The analytical results were used for characterisation of the concentration levels, elemental composition, time trends, enrichment of and relationships among the aerosol species in coarse and fine size fractions, for studying their fine-to-coarse concentration ratios, spatial and temporal variability, for determining detailed elemental mass size distributions, and for examining the extent of chemical mass closure.

M553 sphere forming experiment: Pure nickel specimen evaluation

NASA Technical Reports Server (NTRS)

Johnson, P. C.; Peters, E. T.

1973-01-01

A region or cap of very fine two-dimensional surface growth structure was observed at the top of three of the six pure nickel flight specimens. Such two-dimensional surface growth structures have been observed both on the ground-based specimens and on other surface areas of the flight specimens. However, the fine structures observed on the three flight samples are at least an order of magnitude finer than those previously observed, and resemble similar localized, fine, two-dimensional surface structures observed in both ground and flight specimens for the nickel alloys. The two-dimensional growth areas consist primarily of fine equiaxed grains, specimen SL-2.6, fine dendrites, specimen SL-2.5, or a core of fine equiaxed grains surrounded by a ring of fine dendrites, specimen SL-1.9.

Adsorption and movement of water by skin of the Australian thorny devil (Agamidae: Moloch horridus)

NASA Astrophysics Data System (ADS)

Comanns, Philipp; Esser, Falk J.; Kappel, Peter H.; Baumgartner, Werner; Shaw, Jeremy; Withers, Philip C.

2017-09-01

Moisture-harvesting lizards, such as the Australian thorny devil Moloch horridus, have remarkable adaptations for inhabiting arid regions. Their microstructured skin surface, with channels in between overlapping scales, enables them to collect water by capillarity and passively transport it to the mouth for ingestion. We characterized this capillary water transport for live thorny devils using high-speed video analyses. Comparison with preserved specimens showed that live lizards are required for detailed studies of skin water transport. For thorny devils, there was no directionality in cutaneous water transport (unlike Phrynosoma) as 7 µl water droplets applied to the skin were transported radially over more than 9.2 mm. We calculated the total capillary volume as 5.76 µl cm-2 (dorsal) and 4.45 µl cm-2 (ventral), which is reduced to 50% filling by the time transportation ceases. Using micro-computed tomography and scanning electron microscopy of shed skin to investigate capillary morphology, we found that the channels are hierarchically structured as a large channel between the scales that is sub-divided by protrusions into smaller sub-capillaries. The large channel quickly absorbs water whereas the sub-capillary structure extends the transport distance by about 39% and potentially reduces the water volume required for drinking. An adapted dynamics function, which closely reflects the channel morphology, includes that ecological role.

Adsorption and movement of water by skin of the Australian thorny devil (Agamidae: Moloch horridus).

PubMed

Comanns, Philipp; Esser, Falk J; Kappel, Peter H; Baumgartner, Werner; Shaw, Jeremy; Withers, Philip C

2017-09-01

Moisture-harvesting lizards, such as the Australian thorny devil Moloch horridus , have remarkable adaptations for inhabiting arid regions. Their microstructured skin surface, with channels in between overlapping scales, enables them to collect water by capillarity and passively transport it to the mouth for ingestion. We characterized this capillary water transport for live thorny devils using high-speed video analyses. Comparison with preserved specimens showed that live lizards are required for detailed studies of skin water transport. For thorny devils, there was no directionality in cutaneous water transport (unlike Phrynosoma ) as 7 µl water droplets applied to the skin were transported radially over more than 9.2 mm. We calculated the total capillary volume as 5.76 µl cm -2 (dorsal) and 4.45 µl cm -2 (ventral), which is reduced to 50% filling by the time transportation ceases. Using micro-computed tomography and scanning electron microscopy of shed skin to investigate capillary morphology, we found that the channels are hierarchically structured as a large channel between the scales that is sub-divided by protrusions into smaller sub-capillaries. The large channel quickly absorbs water whereas the sub-capillary structure extends the transport distance by about 39% and potentially reduces the water volume required for drinking. An adapted dynamics function, which closely reflects the channel morphology, includes that ecological role.

Effects of exercise on capillaries in the white matter of transgenic AD mice

PubMed Central

Zhang, Yi; Chao, Feng-Lei; Zhou, Chun-Ni; Jiang, Lin; Zhang, Lei; Chen, Lin-Mu; Luo, Yan-Min; Xiao, Qian; Tang, Yong

2017-01-01

Previous studies have shown that exercise can prevent white matter atrophy in APP/PS1 transgenic Alzheimer’s disease (AD) mice. However, the mechanism of this protective effect remains unknown. To further understand this issue, we investigated the effects of exercise on the blood supply of white matter in transgenic AD mice. Six-month-old male APP/PS1 mice were randomly divided into a control group and a running group, and age-matched non-transgenic littermates were used as a wild-type control group. Mice in the running group ran on a treadmill at low intensity for four months. Then, spatial learning and memory abilities, white matter and white matter capillaries were examined in all mice. The 10-month-old AD mice exhibited deficits in cognitive function, and 4 months of exercise improved these deficits. The white matter volume and the total length, total volume and total surface area of the white matter capillaries were decreased in the 10-month-old AD mice, and 4 months of exercise dramatically delayed the changes in these parameters in the AD mice. Our results demonstrate that even low-intensity running exercise can improve spatial learning and memory abilities, delay white matter atrophy and protect white matter capillaries in early-stage AD mice. Protecting capillaries might be an important structural basis for the exercise-induced protection of the structural integrity of white matter in AD. PMID:29029478

Effects of exercise on capillaries in the white matter of transgenic AD mice.

PubMed

Zhang, Yi; Chao, Feng-Lei; Zhou, Chun-Ni; Jiang, Lin; Zhang, Lei; Chen, Lin-Mu; Luo, Yan-Min; Xiao, Qian; Tang, Yong

2017-09-12

Previous studies have shown that exercise can prevent white matter atrophy in APP/PS1 transgenic Alzheimer's disease (AD) mice. However, the mechanism of this protective effect remains unknown. To further understand this issue, we investigated the effects of exercise on the blood supply of white matter in transgenic AD mice. Six-month-old male APP/PS1 mice were randomly divided into a control group and a running group, and age-matched non-transgenic littermates were used as a wild-type control group. Mice in the running group ran on a treadmill at low intensity for four months. Then, spatial learning and memory abilities, white matter and white matter capillaries were examined in all mice. The 10-month-old AD mice exhibited deficits in cognitive function, and 4 months of exercise improved these deficits. The white matter volume and the total length, total volume and total surface area of the white matter capillaries were decreased in the 10-month-old AD mice, and 4 months of exercise dramatically delayed the changes in these parameters in the AD mice. Our results demonstrate that even low-intensity running exercise can improve spatial learning and memory abilities, delay white matter atrophy and protect white matter capillaries in early-stage AD mice. Protecting capillaries might be an important structural basis for the exercise-induced protection of the structural integrity of white matter in AD.

Computational modeling of the structure-function relationship in human placental terminal villi.

PubMed

Plitman Mayo, R; Olsthoorn, J; Charnock-Jones, D S; Burton, G J; Oyen, M L

2016-12-08

Placental oxygen transport takes place at the final branches of the villous tree and is dictated by the relative arrangement of the maternal and fetal circulations. Modeling techniques have failed to accurately assess the structure-function relationship in the terminal villi due to the geometrical complexity. Three-dimensional blood flow and oxygen transport was modeled in four terminal villi reconstructed from confocal image stacks. The blood flow was analyzed along the center lines of capillary segments and the effect of the variability in capillary diameter, tortuosity and branching was investigated. Additionally, a validation study was performed to corroborate the simulation results. The results show how capillary variations impact motion of the fetal blood, and how their bends and dilatations can decelerate the flow by up to 80%. Vortical flow is also demonstrated not to develop in the fetal capillaries. The different geometries are shown to dictate the transport of gases with differences of over 100% in the oxygen flux between samples. Capillary variations are key for efficient oxygen uptake by the fetus; they allow the blood to decelerate where the villous membrane is thinnest allowing for a better oxygenation, but also by reducing the vessel diameter they carry the oxygenated blood away fast. The methodology employed herein could become a platform to simulate complicated in-vivo and in-vitro scenarios of pregnancy complications. Copyright © 2016 Elsevier Ltd. All rights reserved.

Micro-Textured Black Silicon Wick for Silicon Heat Pipe Array

NASA Technical Reports Server (NTRS)

Yee, Karl Y.; Sunada, Eric T.; Ganapathi, Gani B.; Manohara, Harish; Homyk, Andrew; Prina, Mauro

2013-01-01

Planar, semiconductor heat arrays have been previously proposed and developed; however, this design makes use of a novel, microscale black silicon wick structure that provides increased capillary pumping pressure of the internal working fluid, resulting in increased effective thermal conductivity of the device, and also enables operation of the device in any orientation with respect to the gravity vector. In a heat pipe, the efficiency of thermal transfer from the case to the working fluid is directly proportional to the surface area of the wick in contact with the fluid. Also, the primary failure mechanism for heat pipes operating within the temperature range of interest is inadequate capillary pressure for the return of fluid from the condenser to the wick. This is also what makes the operation of heat pipes orientation-sensitive. Thus, the two primary requirements for a good wick design are a large surface area and high capillary pressure. Surface area can be maximized through nanomachined surface roughening. Capillary pressure is largely driven by the working fluid and wick structure. The proposed nanostructure wick has characteristic dimensions on the order of tens of microns, which promotes menisci of very small radii. This results in the possibility of enormous pumping potential due to the inverse proportionality with radius. Wetting, which also enhances capillary pumping, can be maximized through growth of an oxide layer or material deposition (e.g. TiO2) to create a superhydrophilic surface.

Lennard-Jones fluids in two-dimensional nano-pores. Multi-phase coexistence and fluid structure

NASA Astrophysics Data System (ADS)

Yatsyshin, Petr; Savva, Nikos; Kalliadasis, Serafim

2014-03-01

We present a number of fundamental findings on the wetting behaviour of nano-pores. A popular model for fluid confinement is a one-dimensional (1D) slit pore formed by two parallel planar walls and it exhibits capillary condensation (CC): a first-order phase transition from vapour to capillary-liquid (Kelvin shift). Capping such a pore at one end by a third orthogonal wall forms a prototypical two-dimensional (2D) pore. We show that 2D pores possess a wetting temperature such that below this temperature CC remains of first order, above it becomes a continuous phase transition manifested by a slab of capillary-liquid filling the pore from the capping wall. Continuous CC exhibits hysteresis and can be preceded by a first-order capillary prewetting transition. Additionally, liquid drops can form in the corners of the 2D pore (remnant of 2D wedge prewetting). The three fluid phases, vapour, capillary-liquid slab and corner drops, can coexist at the pore triple point. Our model is based on the statistical mechanics of fluids in the density functional formulation. The fluid-fluid and fluid-substrate interactions are dispersive. We analyze in detail the microscopic fluid structure, isotherms and full phase diagrams. Our findings also suggest novel ways to control wetting of nano-pores. We are grateful to the European Research Council via Advanced Grant No. 247031 for support.

Confocal laser-scanning microscopy of capillaries in normal and psoriatic skin

NASA Astrophysics Data System (ADS)

Archid, Rami; Patzelt, Alexa; Lange-Asschenfeldt, Bernhard; Ahmad, Sufian S.; Ulrich, Martina; Stockfleth, Eggert; Philipp, Sandra; Sterry, Wolfram; Lademann, Juergen

2012-10-01

An important and most likely active role in the pathogenesis of psoriasis has been attributed to changes in cutaneous blood vessels. The purpose of this study was to use confocal laser-scanning microscopy (CLSM) to investigate dermal capillaries in psoriatic and normal skin. The structures of the capillary loops in 5 healthy participants were compared with those in affected skin of 13 psoriasis patients. The diameters of the capillaries and papillae were measured for each group with CLSM. All investigated psoriasis patients showed elongated, widened, and tortuous microvessels in the papillary dermis, whereas all healthy controls showed a single capillary loop in each dermal papilla. The capillaries of the papillary loop and the dermal papilla were significantly enlarged in the psoriatic skin lesions (diameters 24.39±2.34 and 146.46±28.52 μm, respectively) in comparison to healthy skin (diameters 9.53±1.8 and 69.48±17.16 μm, respectively) (P<0.001). CLSM appears to represent a promising noninvasive technique for evaluating dermal capillaries in patients with psoriasis. The diameter of the vessels could be seen as a well-quantifiable indicator for the state of psoriatic skin. CLSM could be useful for therapeutic monitoring to delay possible recurrences.

Titanium based flat heat pipes for computer chip cooling

NASA Astrophysics Data System (ADS)

Soni, Gaurav; Ding, Changsong; Sigurdson, Marin; Bozorgi, Payam; Piorek, Brian; MacDonald, Noel; Meinhart, Carl

2008-11-01

We are developing a highly conductive flat heat pipe (called Thermal Ground Plane or TGP) for cooling computer chips. Conventional heat pipes have circular cross sections and thus can't make good contact with chip surface. The flatness of our TGP will enable conformal contact with the chip surface and thus enhance cooling efficiency. Another limiting factor in conventional heat pipes is the capillary flow of the working fluid through a wick structure. In order to overcome this limitation we have created a highly porous wick structure on a flat titanium substrate by using micro fabrication technology. We first etch titanium to create very tall micro pillars with a diameter of 5 μm, a height of 40 μm and a pitch of 10 μm. We then grow a very fine nano structured titania (NST) hairs on all surfaces of the pillars by oxidation in H202. In this way we achieve a wick structure which utilizes multiple length scales to yield high performance wicking of water. It's capable of wicking water at an average velocity of 1 cm/s over a distance of several cm. A titanium cavity is laser-welded onto the wicking substrate and a small quantity of water is hermetically sealed inside the cavity to achieve a TGP. The thermal conductivity of our preliminary TGP was measured to be 350 W/m-K, but has the potential to be several orders of magnitude higher.

Interfacial gauge methods for incompressible fluid dynamics

PubMed Central

Saye, Robert

2016-01-01

Designing numerical methods for incompressible fluid flow involving moving interfaces, for example, in the computational modeling of bubble dynamics, swimming organisms, or surface waves, presents challenges due to the coupling of interfacial forces with incompressibility constraints. A class of methods, denoted interfacial gauge methods, is introduced for computing solutions to the corresponding incompressible Navier-Stokes equations. These methods use a type of “gauge freedom” to reduce the numerical coupling between fluid velocity, pressure, and interface position, allowing high-order accurate numerical methods to be developed more easily. Making use of an implicit mesh discontinuous Galerkin framework, developed in tandem with this work, high-order results are demonstrated, including surface tension dynamics in which fluid velocity, pressure, and interface geometry are computed with fourth-order spatial accuracy in the maximum norm. Applications are demonstrated with two-phase fluid flow displaying fine-scaled capillary wave dynamics, rigid body fluid-structure interaction, and a fluid-jet free surface flow problem exhibiting vortex shedding induced by a type of Plateau-Rayleigh instability. The developed methods can be generalized to other types of interfacial flow and facilitate precise computation of complex fluid interface phenomena. PMID:27386567

The electromotor system of the electric catfish (Malapterurus electricus): a fine-structural analysis.

PubMed

Janetzko, A; Zimmermann, H; Volknandt, W

1987-03-01

The electromotor system of the electric catfish (Malapterurus electricus) consists of two large ganglion cells situated in the spinal cord, two single axons containing electric nerves and two large electric organs with several million electroplaque cells. The small, irregularly stacked electroplaque cells possess at their center a crater-like indentation from which a stalk like protrusion arises. Many synaptic contacts derived from a single axon collateral are carried on lobe-like protrusions at the terminal knob of this stalk. The electric nerve consists of a large myelinated axon (diameter: 25 micron) surrounded by many layers of connective tissue cells. The two ganglion cells (200 micron in diameter) are rich in elements of the rough endoplasmic reticulum, Golgi apparatus and lysosomal structures. The cytoplasm of the soma changes its appearance towards the voluminous axon hillock (50 micron in diameter) which these organelles do not enter. The cell soma is perforated in a tunnel-like manner by blood capillaries, axons and processes of glial cells. The cell soma and dendrites are covered with two types of synapse. One type forms mixed chemical and electrical (gap junctions) contacts with intermediate attachment plaques. The other type is only chemical in nature. This system may be useful in the study of an identified vertebrate giant neuron.

Gene delivery by direct injection (microinjection) using a controlled-flow system.

PubMed

Dean, David A

2006-12-01

INTRODUCTIONThis protocol describes a method for constant-flow microinjection using the Pneumatic PicoPump (World Precision Instruments). This type of system is very simple and can be assembled on a relatively low budget. In this method, a constant flow of sample is delivered from the tip of the pipette, and the amount of sample injected into the cell is determined by how long the pipette remains in the cell. A typical system is composed of a pressure regulator that can be adjusted for two pressures (back pressure and injection pressure), a capillary holder, and a coarse and fine micromanipulator.

A Preliminary Study of the Spreading of AKD in the Presence of Capillary Structures.

PubMed

Shen, Wei; Parker, Ian H.

2001-08-01

There may be several mechanisms at work in the process of migration or redistribution of alkyl ketene dimers (AKD) on cellulose fiber surfaces during paper sizing and curing. This work is the second part of a continuing investigation of the spreading behavior of AKD on the surfaces of hydrophilic substrates. Paper sheets, single cotton, and cotton lint fibers and smooth cellulose film were used as substrates. These represent samples that have pores, V-shaped grooves, and no capillary structure at all. A very simple and effective testing method for studying the AKD migration behavior through these substrates was designed. AFM was used to study the surface capillary structures of cotton and cotton lint fibers. The results of this study provide hard evidence supporting our finding that capillary structures in the form of either interfiber pores in a paper sheet or V-shaped grooves on the surface of single fibers are essential in order for the spreading of molten AKD on a cellulose substrate to occur. Some preliminary results on the existence and the surface diffusion of an autophobic precursor of AKD are also presented. The results support the conclusion we reached in the first part of this investigation; i.e., the molten AKD wets but does not spread on smooth, capillary-free hydrophilic surfaces such as glass and cellulose. The driving force from interfacial energy alone does not cause spontaneous "flow-like" spreading of molten AKD on these surfaces. This is possibly associated with the formation of an autophobic precursor in front of an AKD droplet. The results in this study do not support the perception that molten AKD forms a single molecular layer on the surface of cellulose fibers by spreading during heat treatment, although the autophobic precursor in front of an AKD droplet could theoretically be of a monolayer thickness and the surface diffusion of this precursor may contribute to the sizing development after heat treatment. Copyright 2001 Academic Press.

Spectacularly robust! Tensegrity principle explains the mechanical strength of the avian lung.

PubMed

Maina, J N

2007-01-15

Among the air-breathing vertebrates, the respiratory system of birds, the lung-air sac system, is remarkably complex and singularly efficient. The most perplexing structural property of the avian lung pertains to its exceptional mechanical strength, especially that of the minuscule terminal respiratory units, the air- and the blood capillaries. In different species of birds, the air capillaries range in diameter from 3 to 20 micro m: the blood capillaries are in all cases relatively smaller. Over and above their capacity to withstand enormous surface tension forces at the air-tissue interface, the air capillaries resist mechanical compression (parabronchial distending pressure) as high as 20 cm H(2)O (2 kPa). The blood capillaries tolerate a pulmonary arterial vascular pressure of 24.1 mmHg (3.2 kPa) and vascular resistance of 22.5 mmHg (3 kPa) without distending. The design of the avian respiratory system fundamentally stems from the rigidity (strength) of the lung. The gas exchanger (the lung) is uncoupled from the ventilator (the air sacs), allowing the lung (the paleopulmonic parabronchi) to be ventilated continuously and unidirectionally by synchronized bellows like action of the air sacs. Since during the ventilation of the lung the air capillaries do not have to be distended (dilated), i.e., surface tension force does not have to be overcome (as would be the case if the lung was compliant), extremely intense subdivision of the exchange tissue was possible. Minuscule terminal respiratory units developed, producing a vast respiratory surface area in a limited lung volume. I make a case that a firm (rigid) rib cage, a lung tightly held by the ribs and the horizontal septum, a lung directly attached to the trunk, specially formed and compactly arranged parabronchi, intertwined atrial muscles, and tightly set air capillaries and blood capillaries form an integrated hierarchy of discrete network system of tension and compression, a tensegrity (tensional integrity) array, which absorbs, transmits, and dissipates stress, stabilizing (strengthening) the lung and its various structural components.

Isolation, synthesis and anti-hepatitis B virus evaluation of p-hydroxyacetophenone derivatives from Artemisia capillaris.

PubMed

Zhao, Yong; Geng, Chang-An; Chen, Hao; Ma, Yun-Bao; Huang, Xiao-Yan; Cao, Tuan-Wu; He, Kang; Wang, Hao; Zhang, Xue-Mei; Chen, Ji-Jun

2015-04-01

p-Hydroxyacetophenone (p-HAP), as a main hepatoprotective and choleretic constituent of Artemisia capillaris, was revealed with anti-hepatitis B virus (HBV) effects in recent investigation. In addition to p-HAP, four derivatives of p-HAP were also isolated from A. capillaris by various chromatographic methods. Subsequent structural modification on p-HAP and its glycoside led to the synthesis of 28 additional derivatives, of which 13 compounds showed activity inhibiting hepatitis B surface antigen (HBsAg) secretion; and 18 compounds possessed inhibition on HBV DNA replication. The primary structure-activity relationships (SARs) suggested that the conjugated derivatives of p-HAP glycoside and substituted cinnamic acids (2a-2i) obviously enhanced the activity against HBV DNA replication with IC50 values ranged from 5.8 to 74.4 μM. Copyright © 2015 Elsevier Ltd. All rights reserved.

Fibronectin non-amyloid glomerulopathy.

PubMed

Yong, Jim L; Killingsworth, Murray C; Spicer, S Timothy; Wu, Xiao-Juan

2009-11-20

A 41-year-old Burmese man presented with nephrotic syndrome, a creatinine level of 150 micromol/L and limited clinical history. His renal biopsy demonstrated glomerulopathy with large eosinophilic deposits in the mesangium and capillary loops that were negative for Congo red, slightly positive for periodic acid-Schiff and blue with Masson trichrome stain. Immunofluorescence microscopy with a routine antibody panel was unhelpful. Electron microscopy demonstrated extensive, moderately electron-dense deposits in the subendothelial space, subepithelial space and mesangium that could be differentiated from adjacent basement membrane by their increased electron density. The deposits contained finely granular material and occasional filaments with variable diameter ranging from 9-16 nm. Fibronectin glomerulopathy was suspected from anti-fibronectin immunohistochemistry that showed positive staining of thickened capillary loops. This staining was subsequently confirmed by immunoelectron microscopy demonstrating the presence of cellular fibronectin (cFN) in deposits. Significantly, deposition of fibronectin appeared to have occurred in the absence of thickening or folding of the adjacent basement membrane. The prominent mesangial location of deposits containing a cFN isotype may indicate that retention of local fibronectin produced in the mesangium has contributed to this pathology.

Fibronectin non-amyloid glomerulopathy

PubMed Central

Yong, Jim L; Killingsworth, Murray C; Spicer, S Timothy; Wu, Xiao-Juan

2010-01-01

A 41-year-old Burmese man presented with nephrotic syndrome, a creatinine level of 150 µmol/L and limited clinical history. His renal biopsy demonstrated glomerulopathy with large eosinophilic deposits in the mesangium and capillary loops that were negative for Congo red, slightly positive for periodic acid-Schiff and blue with Masson trichrome stain. Immunofluorescence microscopy with a routine antibody panel was unhelpful. Electron microscopy demonstrated extensive, moderately electron-dense deposits in the subendothelial space, subepithelial space and mesangium that could be differentiated from adjacent basement membrane by their increased electron density. The deposits contained finely granular material and occasional filaments with variable diameter ranging from 9-16 nm. Fibronectin glomerulopathy was suspected from anti-fibronectin immunohistochemistry that showed positive staining of thickened capillary loops. This staining was subsequently confirmed by immunoelectron microscopy demonstrating the presence of cellular fibronectin (cFN) in deposits. Significantly, deposition of fibronectin appeared to have occurred in the absence of thickening or folding of the adjacent basement membrane. The prominent mesangial location of deposits containing a cFN isotype may indicate that retention of local fibronectin produced in the mesangium has contributed to this pathology. PMID:20126589

Vascular development in the vertebrate pancreas

PubMed Central

Azizoglu, D. Berfin; Chong, Diana C.; Villasenor, Alethia; Magenheim, Judith; Barry, David M.; Lee, Simon; Marty-Santos, Leilani; Fu, Stephen; Dor, Yuval; Cleaver, Ondine

2016-01-01

The vertebrate pancreas is comprised of a highly branched tubular epithelium, which is intimately associated with an extensive and specialized vasculature. While we know a great deal about basic vascular anatomy of the adult pancreas, as well as islet capillaries, surprisingly little is known about the ontogeny of its blood vessels. Here, we analyze development of the pancreatic vasculature in the mouse embryo. We show that pancreatic epithelial branches intercalate with the fine capillary plexus of the surrounding pancreatic mesenchyme. Endothelial cells (ECs) within this mesenchyme are heterogeneous from the onset of organogenesis. Pancreatic arteries take shape before veins, in a manner analogous to early embryonic vessels. The main central artery forms during mid-gestation, as a result of vessel coalescence and remodeling of a vascular plexus. In addition, we show that vessels in the forming pancreas display a predictable architecture that is dependent on VEGF signaling. Over-expression of VEGF disrupts vascular patterning and arteriovenous differentiation within the developing pancreas. This study constitutes a first-time cellular and molecular characterization of pancreatic blood vessels, as they coordinately grow along with the pancreatic epithelium. PMID:27789228

Numerical Analysis of Infiltration Into a Sand Profile Bounded by a Capillary Fringe

NASA Astrophysics Data System (ADS)

Curtis, Alan A.; Watson, Keith K.

1980-04-01

The rapid response sometimes observed in a tile drain system following surface ponding of water is discussed in terms of the air compressibility effect. An earlier numerical study describing water movement into a bounded profile with a lower boundary impermeable to the passage of both air and water is reviewed with particular reference to the validity of the time-dependent boundary condition transformation used in simulating the inhibiting effects of the air pressure increase on infiltration. The extension of the transformation approach to a profile bounded by a capillary fringe is then considered in detail, and the results of numerical analyses are presented for infiltration into two columns of a fine sand initially in hydraulic equilibrium from a prior gravity drainage regime. The shorter column develops a steady state flow condition at short times which is consistent with earlier experimental findings. In contrast, the pressure of the entrapped air in the longer column gradually increases as infiltration proceeds until the analysis is terminated when air escape through the lower boundary is imminent.

Profile of capillary bridges between two vertically stacked cylindrical fibers under gravitational effect

NASA Astrophysics Data System (ADS)

Sun, Xiaohang; Lee, Hoon Joo; Michielsen, Stephen; Wilusz, Eugene

2018-05-01

Although profiles of axisymmetric capillary bridges between two cylindrical fibers have been extensively studied, little research has been reported on capillary bridges under external forces such as the gravitational force. This is because external forces add significant complications to the Laplace-Young equation, making it difficult to predict drop profiles based on analytical approaches. In this paper, simulations of capillary bridges between two vertically stacked cylindrical fibers with gravitational effect taken into consideration are studied. The asymmetrical structure of capillary bridges that are hard to predict based on analytical approaches was studied via a numerical approach based on Surface Evolver (SE). The axial and the circumferential spreading of liquids on two identical fibers in the presence of gravitational effects are predicted to determine when the gravitational effects are significant or can be neglected. The effect of liquid volume, equilibrium contact angle, the distance between two fibers and fiber radii. The simulation results were verified by comparing them with experimental measurements. Based on SE simulations, curves representing the spreading of capillary bridges along the two cylindrical fibers were obtained. The gravitational effect was scaled based on the difference of the spreading on upper and lower fibers.

Moisture harvesting and water transport through specialized micro-structures on the integument of lizards.

PubMed

Comanns, Philipp; Effertz, Christian; Hischen, Florian; Staudt, Konrad; Böhme, Wolfgang; Baumgartner, Werner

2011-01-01

Several lizard species that live in arid areas have developed special abilities to collect water with their bodies' surfaces and to ingest the so collected moisture. This is called rain- or moisture-harvesting. The water can originate from air humidity, fog, dew, rain or even from humid soil. The integument (i.e., the skin plus skin derivatives such as scales) has developed features so that the water spreads and is soaked into a capillary system in between the reptiles' scales. Within this capillary system the water is transported to the mouth where it is ingested. We have investigated three different lizard species which have developed the ability for moisture harvesting independently, viz. the Australian thorny devil (Moloch horridus), the Arabian toadhead agama (Phrynocephalus arabicus) and the Texas horned lizard (Phrynosoma cornutum). All three lizards have a honeycomb like micro ornamentation on the outer surface of the scales and a complex capillary system in between the scales. By investigation of individual scales and by producing and characterising polymer replicas of the reptiles' integuments, we found that the honeycomb like structures render the surface superhydrophilic, most likely by holding a water film physically stable. Furthermore, the condensation of air humidity is improved on this surface by about 100% in comparison to unstructured surfaces. This allows the animals to collect moisture with their entire body surface. The collected water is transported into the capillary system. For Phrynosoma cornutum we found the interesting effect that, in contrast to the other two investigated species, the water flow in the capillary system is not uniform but directed to the mouth. Taken together we found that the micro ornamentation yields a superhydrophilic surface, and the semi-tubular capillaries allow for an efficient passive - and for Phrynosoma directed - transport of water.

Open tubular capillary columns with basic templates made by the generalized preparation protocol in capillary electrochromatography chiral separation and template structural effects on chiral separation capability.

PubMed

Zaidi, Shabi Abbas; Lee, Seung Mi; Cheong, Won Jo

2011-03-04

Some open tubular (OT) molecule imprinted polymer (MIP) silica capillary columns have been prepared using atenolol, sulpiride, methyl benzylamine (MBA) and (1-naphthyl)-ethylamine (NEA) as templates by the pre-established generalized preparation protocol. The four MIP thin layers of different templates showed quite different morphologies. The racemic selectivity of each MIP column for the template enantiomers was optimized by changing eluent composition and pH. The template structural effects on chiral separation performance have been examined. This work verifies the versatility of the generalized preparation protocol for OT-MIP silica capillary columns by extending its boundary toward templates with basic functional group moieties. This study is the very first report to demonstrate a generalized MIP preparation protocol that is valid for both acidic and basic templates. The chiral separation performances of atenolol and sulpiride by the MIPs of this study were found better than or comparable to those of atenolol and sulpiride obtained by non-MIP separation techniques and those of some basic template enantiomers obtained by MIP based techniques. Copyright © 2011 Elsevier B.V. All rights reserved.

Fine structure of heliumlike ions and determination of the fine structure constant.

PubMed

Pachucki, Krzysztof; Yerokhin, Vladimir A

2010-02-19

We report a calculation of the fine-structure splitting in light heliumlike atoms, which accounts for all quantum electrodynamical effects up to order alpha{5} Ry. For the helium atom, we resolve the previously reported disagreement between theory and experiment and determine the fine-structure constant with an accuracy of 31 ppb. The calculational results are extensively checked by comparison with the experimental data for different nuclear charges and by evaluation of the hydrogenic limit of individual corrections.

Stability and characterization of perphenazine aerosols generated using the capillary aerosol generator.

PubMed

Li, Xihao; Blondino, Frank E; Hindle, Michael; Soine, William H; Byron, Peter R

2005-10-13

Perphenazine (a potent antiemetic) was aerosolized using capillary aerosol generator to generate respirable condensation aerosols from drug in propylene glycol (PG) solutions, by pumping the liquids through a heated capillary tube. The study characterized the stability of perphenazine during and following aerosol generation. The stability-indicating HPLC method (C-8 column with a mobile phase of 52% 0.01 M pH 3.0 acetate buffer+48% acetonitrile) also enabled the study of perphenazine stability in solution under acidic, basic, oxidizing and photolysing conditions. An LC-MS (ESI+) method was used to characterize the degradation products. Perphenazine was found to be stable in acidic and basic conditions, while perphenazine sulfoxide was the major product formed in dilute peroxide solutions. Two photo-degradation products were formed in PG that were tentatively identified by LC-MS; one of these was synthesized and confirmed to be 2-[4-(3-phenothiazin-10-yl-propyl)-piperazino]-ethanol. Both photolysis products showed that aromatic dechlorination had occurred and one appeared to also result from interaction with the solvent. Within an aerosolization energy window of 84-95 J, fine particle aerosols were generated from perphenazine PG formulations with no significant degradation. Small amounts of degradation products were produced in all samples during aerosolization at elevated (non-optimal) energies. These were largely consistent with those seen to result from oxidation and photolysis in solution, showing that oxidation and dehalogenation appeared to be the main degradation pathways followed when the CAG system was overheated.

Chiral separation of terbutaline and non-steroidal anti-inflammatory drugs by using a new lysine-bridged hemispherodextrin in capillary electrophoresis.

PubMed

Cucinotta, V; Messina, M; Contino, A; Maccarrone, G; Orlandini, S; Giuffrida, A

2017-10-25

A method for the separation of a mixture of terbutaline and non-steroidal anti-inflammatory drugs was developed using capillary electrophoresis with a new hemispherodextrin, ad hoc designed, the lysine - bridged hemispherodextrin (THLYSH). The use of lysine residues to bridge the trehalose capping unit moiety to the cyclodextrin cavity gives rise to a receptor with two long chains with amine nitrogen atoms, whose charge can be easily tuned as a function of the solution pH. The new hemispherodextrin was accurately characterised by ESI-MS and NMR spectroscopy, also highlighting its protonation behaviour. Circular dichroism and ESR spectroscopy measurements were also carried out to test its inclusion ability towards anthraquinone-3-sulfonate and its metal coordination ability towards copper(II) ion, respectively. Analogously to the other hemispherodextrins, the main skill of this new derivative lies in its chiral selector properties, as shown by the separation of the enantiomeric pairs of terbutaline and ibuprofen, flurbiprofen, suprofen and tiaprofenic acid by capillary electrophoresis. The focused use of the solution equilibria involved in the separations made it possible to understand the phenomena occurring in solution, and to finely tune the charge status of the receptor. In this way the chiral separation of the racemic mixture was successfully obtained, even if the receptor was individually used, differently by the other hemispherodextrins previously studied whose chiral separation capabilities are present only if used as binary mixtures. Copyright © 2017 Elsevier B.V. All rights reserved.

Transport through a network of capillaries from ultrametric diffusion equation with quadratic nonlinearity

NASA Astrophysics Data System (ADS)

Oleschko, K.; Khrennikov, A.

2017-10-01

This paper is about a novel mathematical framework to model transport (of, e.g., fluid or gas) through networks of capillaries. This framework takes into account the tree structure of the networks of capillaries. (Roughly speaking, we use the tree-like system of coordinates.) As is well known, tree-geometry can be topologically described as the geometry of an ultrametric space, i.e., a metric space in which the metric satisfies the strong triangle inequality: in each triangle, the third side is less than or equal to the maximum of two other sides. Thus transport (e.g., of oil or emulsion of oil and water in porous media, or blood and air in biological organisms) through networks of capillaries can be mathematically modelled as ultrametric diffusion. Such modelling was performed in a series of recently published papers of the authors. However, the process of transport through capillaries can be only approximately described by the linear diffusion, because the concentration of, e.g., oil droplets, in a capillary can essentially modify the dynamics. Therefore nonlinear dynamical equations provide a more adequate model of transport in a network of capillaries. We consider a nonlinear ultrametric diffusion equation with quadratic nonlinearity - to model transport in such a network. Here, as in the linear case, we apply the theory of ultrametric wavelets. The paper also contains a simple introduction to theory of ultrametric spaces and analysis on them.

Three-dimensional analysis of alveolar wall destruction in the early stage of pulmonary emphysema.

PubMed

Kobayashi, Yukihiro; Uehara, Takeshi; Kawasaki, Kenji; Sugano, Mitsutoshi; Matsumoto, Takehisa; Matsumoto, Gou; Honda, Takayuki

2015-03-01

The morphological mechanism of alveolar wall destruction during pulmonary emphysema has not been clarified. The aim of this study was to elucidate this process three-dimensionally. Lung specimens from five patients with pulmonary emphysema were used, and five controls with normal alveolar structure were also examined. Sections 150 μm thick were stained with hematoxylin and eosin, elastica, and silver impregnation, and immunostained with selected antibodies. We examined these sections three-dimensionally using a laser confocal microscope and a light microscope. There were only a few Kohn's pores and no fenestrae in the normal alveoli from the controls. In the lungs of the emphysema patients a small rupture appeared in the extremely thin alveolar wall among the alveolar capillaries. This rupture enlarged to form a circle surrounded by the capillaries, which was called an alveolar fenestra. Two neighboring fenestrae fused by breakdown of the collapsed or cord-like capillary between them to form a large fenestra. The large fenestrae fused repeatedly to become larger, and these were bordered by thick elastic fibers constructing an alveolar framework. Alveolar wall destruction during emphysema could start from small ruptures of the alveolar wall that become fenestrae surrounded by capillaries, which fuse repeatedly to become larger fenestrae rimmed with elastic fibers. The alveolar capillary network could initially prevent enlargement of the fenestrae, and the thick elastic fibers constituting the alveolar framework could secondarily prevent destruction of the alveolar wall structure. © 2014 Wiley Periodicals, Inc.

Separation of 2-aminobenzoic acid-derivatized glycosaminoglycans and asparagine-linked glycans by capillary electrophoresis.

PubMed

Sato, Kae; Sato, Kiichi; Okubo, Akira; Yamazaki, Sunao

2005-01-01

A capillary electrophoresis method was developed for the analysis of oligosaccharides combined with derivatization with 2-aminobenzoic acid. Glycosaminoglycan delta-disaccharides were effectively resolved on a fused-silica capillary tube using 150 mM borate, pH 8.5, as a running electrolyte solution. This analytical method was applied to the identification of glycosaminoglycan in combination with enzymatic digestion. The separation of N-glycans or glucose-oligomers was performed with a phosphate buffer containing polyethylene glycol or borate as an electrolyte solution. This method is expected to be useful in the determination of oligosaccharide structures in a glycoprotein.

Endoscopic ultrasound-guided fine needle aspiration cytology diagnosis of solid pseudopapillary tumor of the pancreas: a report of 3 cases.

PubMed

Chatzipantelis, Paschalis; Salla, Charitini; Apostolou, George; Christodoulou, Lambrini; Kakiopoulos, George; Patralexis, Charalambos

2010-01-01

Solid pseudopapillary tumor of the pancreas (SPTP) is an exceedingly rare pancreatic tumor. We present the clinical, endoscopic ultrasound (EUS)-guided fine needle aspiration (FNA) cytologic features and immunohistochemical findings performed on cell blocks of 3 SPTPs. Three females (17-32 years old) were admitted to our hospital due to unexplained episodic abdominal pain. EUS confirmed the presence of a mass in the body and tail of the pancreas (2 cases) and in the head (1 case), with distinct borders and occassional dilation of the peripheral part of the pancreatic duct. EUS-FNA cytology specimens consisted of single cells and aggregates of uniform polyhedral cells, forming branching papillary clusters with delicate fibrovascular cores and nuclear overlapping (2 cases) and glandlike structures (1 case). Variable hyaline, myxoid stromal elements and naked capillaries were also seen. The cells had bland nuclear features, small nucleoli, nuclear grooves in some of them and focally cytoplasmic projections. Mitoses and necrosis were not observed. The immunohistochemistry on cell blocks revealed: vimentin+ (3 cases), CA19.9+ (2 cases), cytokeratin 7+ (focal, intensive, 1 case), synaptophysin+ (1 case), MUC1+ (focal, intensive, 1 case), EMA+ (diffuse weak, 1 case), a1-antitrypsin and a1-antichymotrypsin+ (focal intensive, 2 cases), progesterone+ (1 case), chromogranin-A- (3 cases) and NSE- (3 cases). Cytologic and immunohistochemical findings were strongly suggestive of SPTP. Surgical resection confirmed the diagnosis in all cases. EUS-FNA cytology features and immunohistochemistry provide the diagnosis of SPTP with accuracy.

Physical structure changes of solid medium by steam explosion sterilization.

PubMed

Zhao, Zhi-Min; Wang, Lan; Chen, Hong-Zhang

2016-03-01

Physical structure changes of solid medium were investigated to reveal effects of steam explosion sterilization on solid-state fermentation (SSF). Results indicated that steam explosion changed the structure of solid medium at both molecular and three-dimensional structural levels, which exposed hydrophilic groups and enlarged pores and cavities. It was interesting to find that pores where capillary water located were the active sites for SSF, due to the close relationship among capillary water relaxation time, specific surface area and fermentation performance. Therefore, steam explosion sterilization increased the effective contact area for microbial cells on solid medium, which contributed to improving SSF performance. Combined with the previous research, mechanisms of SSF improvement by steam explosion sterilization contained both chemical and physical effects. Copyright © 2015 Elsevier Ltd. All rights reserved.

A Review of String Vessels or Collapsed, Empty Basement Membrane Tubes

PubMed Central

Brown, William R.

2011-01-01

String vessels are thin connective tissue strands, remnants of capillaries, with no endothelial cells; they do not carry blood flow. They occur in numerous species, particularly in the central nervous system, but can occur in any tissue where capillaries have died. String vessels are often associated with pathologies such as Alzheimer’s disease, ischemia, and irradiation, but are also found in normal human brains from preterm babies to the aged. They provide a record of the original blood vessel location, but gradually disappear after months or years. There have been numerous studies of string vessels (acellular capillaries) in the retina, because retinal vessels can be seen in great detail in whole mounts after trypsin digestion. Capillary regression occurs by apoptosis, synchronously along capillary segments, with macrophages engulfing apoptotic endothelial cells. Macrophages may cause the apoptosis, or the regression may be triggered by loss of the endothelial cell survival factor VEGF. VEGF expression is induced by hypoxia and promotes capillary growth. Cessation of blood flow eliminates the shear stress that helps maintain endothelial cell survival. Capillaries can re-grow by proliferation and migration of endothelial cells into empty basement membrane tubes, which provide a structural scaffold, replete with signaling molecules. This is a problem in tumor control, but useful for recovery from capillary loss. There is an age-related waning of VEGF expression in response to hypoxia. This causes an age-related decline in cerebral angiogenesis and results in neuronal loss. It may also contribute to the proposed age-related loss of brain reserve. PMID:20634580

Analysis of retinal capillaries in patients with type 1 diabetes and nonproliferative diabetic retinopathy using adaptive optics imaging.

PubMed

Lombardo, Marco; Parravano, Mariacristina; Serrao, Sebastiano; Ducoli, Pietro; Stirpe, Mario; Lombardo, Giuseppe

2013-09-01

To illustrate a noninvasive method to analyze the retinal capillary lumen caliber in patients with Type 1 diabetes. Adaptive optics imaging of the retinal capillaries were acquired in two parafoveal regions of interest in eyes with nonproliferative diabetic retinopathy and unaffected controls. Measures of the retinal capillary lumen caliber were quantified using an algorithm written in Matlab by an independent observer in a masked manner. Comparison of the adaptive optics images with red-free and color wide fundus retinography images was also assessed. Eight eyes with nonproliferative diabetic retinopathy (eight patients, study group), no macular edema, and preserved visual acuity and eight control eyes (eight healthy volunteers; control group) were analyzed. The repeatability of capillary lumen caliber measurements was 0.22 μm (3.5%) with the 95% confidence interval between 0.12 and 0.31 μm in the study group. It was 0.30 μm (4.1%) with the 95% confidence interval between 0.16 and 0.43 μm in the control group. The average capillary lumen caliber was significantly narrower in eyes with nonproliferative diabetic retinopathy (6.27 ± 1.63 μm) than in the control eyes (7.31 ± 1.59 μm, P = 0.002). The authors demonstrated a noninvasive method to analyze, with micrometric scale of resolution, the lumen of retinal capillaries. The parafoveal capillaries were narrower in patients with Type 1 diabetes and nonproliferative diabetic retinopathy than in healthy subjects, showing the potential capability of adaptive optics imaging to detect pathologic variations of the retinal microvascular structures in vaso-occlusive diseases.

An Amorphous Network Model for Capillary Flow and Dispersion in a Partially Saturated Porous Medium

NASA Astrophysics Data System (ADS)

Simmons, C. S.; Rockhold, M. L.

2013-12-01

Network models of capillary flow are commonly used to represent conduction of fluids at pore scales. Typically, a flow system is described by a regular geometric lattice of interconnected tubes. Tubes constitute the pore throats, while connection junctions (nodes) are pore bodies. Such conceptualization of the geometry, however, is questionable for the pore scale, where irregularity clearly prevails, although prior published models using a regular lattice have demonstrated successful descriptions of the flow in the bulk medium. Here a network is allowed to be amorphous, and is not subject to any particular lattice structure. Few network flow models have treated partially saturated or even multiphase conditions. The research trend is toward using capillary tubes with triangular or square cross sections that have corners and always retain some fluid by capillarity when drained. In contrast, this model uses only circular capillaries, whose filled state is controlled by a capillary pressure rule for the junctions. The rule determines which capillary participate in the flow under an imposed matric potential gradient during steady flow conditions. Poiseuille's Law and Laplace equation are used to describe flow and water retention in the capillary units of the model. A modified conjugate gradient solution for steady flow that tracks which capillary in an amorphous network contribute to fluid conduction was devised for partially saturated conditions. The model thus retains the features of classical capillary models for determining hydraulic flow properties under unsaturated conditions based on distribution of non-interacting tubes, but now accounts for flow exchange at junctions. Continuity of the flow balance at every junction is solved simultaneously. The effective water retention relationship and unsaturated permeability are evaluated for an extensive enough network to represent a small bulk sample of porous medium. The model is applied for both a hypothetically randomly generate network and for a directly measured porous medium structure, by means of xray-CT scan. A randomly generated network has the benefit of providing ensemble averages for sample replicates of a medium's properties, whereas network structure measurements are expected to be more predictive. Dispersion of solute in a network flow is calculate by using particle tracking to determine the travel time breakthrough between inflow and outflow boundaries. The travel time distribution can exhibit substantial skewness that reflects both network velocity variability and mixing dilution at junctions. When local diffusion is not included, and transport is strictly advective, then the skew breakthrough is not due to mobile-immobile flow region behavior. The approach of dispersivity to its asymptotic value with sample size is examined, and may be only an indicator of particular stochastic flow variation. It is not proven that a simplified network flow model can accurately predict the hydraulic properties of a sufficiently large-size medium sample, but such a model can at least demonstrate macroscopic flow resulting from the interaction of physical processes at pore scales.

Fine-scale structure in the far-infrared Milky-Way

NASA Technical Reports Server (NTRS)

Waller, William H.; Wall, William F.; Reach, William T.; Varosi, Frank; Ebert, Rick; Laughlin, Gaylin; Boulanger, Francois

1995-01-01

This final report summarizes the work performed and which falls into five broad categories: (1) generation of a new data product (mosaics of the far-infrared emission in the Milky Way); (2) acquisition of associated data products at other wavelengths; (3) spatial filtering of the far-infrared mosaics and resulting images of the FIR fine-scale structure; (4) evaluation of the spatially filtered data; (5) characterization of the FIR fine-scale structure in terms of its spatial statistics; and (6) identification of interstellar counterparts to the FIR fine-scale structure.

Enantioseparation on cellulose dimethylphenylcarbamate-modified zirconia monolithic columns by reversed-phase capillary electrochromatography.

PubMed

Kumar, Avvaru Praveen; Park, Jung Hag

2010-06-25

This work reports the preparation of monolithic zirconia chiral columns for separation of enantiomeric compounds by capillary electrochromatography (CEC). Using sol-gel technology, a porous monolith having interconnected globular-like structure with through-pores is synthesized in the capillary column as a first step in the synthesis of monolithic zirconia chiral capillary columns. In the second step, the surface of the monolith is modified by coating with cellulose tris(3,5-dimethylphenylcarbamate) (CDMPC) as the chiral stationary phase to obtain a chiral column (CDMPCZM). The process of the preparation of the zirconia monolithic capillary column was investigated by varying the concentrations of the components of the sol solution including polyethylene glycol, water and acetic acid. CDMPCZM is mechanically stable and no bubble formation was detected with the applied current of up to 30 microA. The enantioseparation behavior of the CDMPCZM columns was investigated by separating a set of 10 representative chiral compounds by varying the applied voltage and pH and organic composition of the aqueous organic mobile phases. Copyright 2010 Elsevier B.V. All rights reserved.

Fabrication of powdery polymer aerogel as the stationary phase for high-resolution gas chromatographic separation.

PubMed

Zheng, Juan; Lu, Cuiming; Huang, Junlong; Chen, Luyi; Ni, Chuyi; Xie, Xintong; Zhu, Fang; Wu, Dingcai; Ouyang, Gangfeng

2018-08-15

Novel powdery polymer aerogel (PPA) prepared via the (micro)emulsion polymerization and the following hyper crosslinking reaction was fabricated as stationary phase of capillary column for the first time. Due to its powdery morphology, unique 3D nano-network structure, high surface area and good thermostability, the PPA-coated capillary column demonstrated high-resolution chromatographic separation towards nonpolar and weakly polar organic compounds, including benzene series, n-alkanes, ketone mixtures and trichlorobenzenes. Moreover, the reproducibility, quantitative analysis ability and thermostability of PPA-coated capillary column were also evaluated. The relative standard deviations for three replicate determinations of selected analytes were 0.02-0.11%, 0.12-0.26% and 1.2-3.6% for run-to-run, day-to-day and column-to-column analyses, respectively. The PPA demonstrated good thermostability, and the PPA-coated capillary column was proved to be heat-resistant (270 °C). The results of this study show PPA is an excellent candidate to be employed as stationary phase for gas chromatography capillary. Copyright © 2018 Elsevier B.V. All rights reserved.

Significant differences in ion and electron guiding through highly insulating capillaries

NASA Astrophysics Data System (ADS)

Stolterfoht, N.; Tanis, J.

2018-04-01

Outstanding phenomena of capillary guiding are discussed in accordance with a recent review in the field. Experiments concerning highly charged ions of a few keV energy guided through insulating nanocapillaries are shown. Studies of the temporal evolution of ion transmission are presented. Attention is focused on oscillatory structures in the ion emission and the independence of the ion guiding on the beam intensity. A few experiments of electron guiding are presented showing a significantly different temporal evolution of the transmitted intensity. The onset of the electron transmission is very sudden accompanied by a considerable energy loss within the capillary. To achieve more insight into the different guiding mechanisms, theoretical aspects of the capillary guiding are analyzed. A scenario is offered to explain the abrupt rise of transmitted electrons. Altogether, these studies show that ion and electron guiding are accomplished through different manifestations of the charge build up that underlies both.

Using evaporation to control capillary instabilities in micro-systems.

PubMed

Ledesma-Aguilar, Rodrigo; Laghezza, Gianluca; Yeomans, Julia M; Vella, Dominic

2017-12-06

The instabilities of fluid interfaces represent both a limitation and an opportunity for the fabrication of small-scale devices. Just as non-uniform capillary pressures can destroy micro-electrical mechanical systems (MEMS), so they can guide the assembly of novel solid and fluid structures. In many such applications the interface appears during an evaporation process and is therefore only present temporarily. It is commonly assumed that this evaporation simply guides the interface through a sequence of equilibrium configurations, and that the rate of evaporation only sets the timescale of this sequence. Here, we use Lattice-Boltzmann simulations and a theoretical analysis to show that, in fact, the rate of evaporation can be a factor in determining the onset and form of dynamical capillary instabilities. Our results shed light on the role of evaporation in previous experiments, and open the possibility of exploiting diffusive mass transfer to directly control capillary flows in MEMS applications.

Effect of Pore Size and Pore Connectivity on Unidirectional Capillary Penetration Kinetics in 3-D Porous Media using Direct Numerical Simulation

NASA Astrophysics Data System (ADS)

Fu, An; Palakurthi, Nikhil; Konangi, Santosh; Comer, Ken; Jog, Milind

2017-11-01

The physics of capillary flow is used widely in multiple fields. Lucas-Washburn equation is developed by using a single pore-sized capillary tube with continuous pore connection. Although this equation has been extended to describe the penetration kinetics into porous medium, multiple studies have indicated L-W does not accurately predict flow patterns in real porous media. In this study, the penetration kinetics including the effect of pore size and pore connectivity will be closely examined since they are expected to be the key factors effecting the penetration process. The Liquid wicking process is studied from a converging and diverging capillary tube to the complex virtual 3-D porous structures with Direct Numerical Simulation (DNS) using the Volume-Of-Fluid (VOF) method within the OpenFOAM CFD Solver. Additionally Porous Medium properties such as Permeability (k) , Tortuosity (τ) will be also analyzed.

GPR monitoring for non-uniform infiltration through a high permeable gravel layer in the test sand box

NASA Astrophysics Data System (ADS)

Kuroda, Seiichiro; Ishii, Nobuyuki; Morii, Toshihiro

2017-04-01

Recently capillary barriers have been known as a method to protect subsurface regions against infiltration from soil surface. It has essentially non-uniform structure of permeability or soil physical property. To identify the function of the capillary barrier, the site-characterization technique for non-uniform soil moisture distribution and infiltration process is needed. We built a sand box in which a thin high-permeable gravel layer was embedded and conducted a infiltration test, including non-uniform flow of soil water induced by capillary barrier effects. We monitored this process by various types of GPR measurements, including time-lapsed soundings with multi-frequency antenna and transmission measurements like one using cross-borehole radar. Finally we will discuss the applicability of GPR for monitoring the phenomena around the capillary barrier of soil. This work has partially supported by JSPS Grant-in-aid Scientific Research program, No.16H02580.

Visualization of the microcirculatory network in skin by high frequency optoacoustic mesoscopy

NASA Astrophysics Data System (ADS)

Schwarz, Mathias; Aguirre, Juan; Buehler, Andreas; Omar, Murad; Ntziachristos, Vasilis

2015-07-01

Optoacoustic (photoacoustic) imaging has a high potential for imaging melanin-rich structures in skin and the microvasculature of the dermis due to the natural chromophores (de)oxyhemoglobin, and melanin. The vascular network in human dermis comprises a large network of arterioles, capillaries, and venules, ranging from 5 μm to more than 100 μm in diameter. The frequency spectrum of the microcirculatory network in human skin is intrinsically broadband, due to the large variety in size of absorbers. In our group we have developed raster-scan optoacoustic mesoscopy (RSOM) that applies a 100 MHz transducer with ultra-wide bandwidth in raster-scan mode achieving lateral resolution of 18 μm. In this study, we applied high frequency RSOM to imaging human skin in a healthy volunteer. We analyzed the frequency spectrum of anatomical structures with respect to depth and show that frequencies >60 MHz contain valuable information of structures in the epidermis and the microvasculature of the papillary dermis. We illustrate that RSOM is capable of visualizing the fine vascular network at and beneath the epidermal-dermal junction, revealing the vascular fingerprint of glabrous skin, as well as the larger venules deeper inside the dermis. We evaluate the ability of the RSOM system in measuring epidermal thickness in both hairy and glabrous skin. Finally, we showcase the capability of RSOM in visualizing benign nevi that will potentially help in imaging the penetration depth of melanoma.

Droplet spreading and capillary imbibition in a porous medium: A coupled IB-VOF method based numerical study

NASA Astrophysics Data System (ADS)

Das, Saurish; Patel, H. V.; Milacic, E.; Deen, N. G.; Kuipers, J. A. M.

2018-01-01

We investigate the dynamics of a liquid droplet in contact with a surface of a porous structure by means of the pore-scale level, fully resolved numerical simulations. The geometrical details of the solid porous matrix are resolved by a sharp interface immersed boundary method on a Cartesian computational grid, whereas the motion of the gas-liquid interface is tracked by a mass conservative volume of fluid method. The numerical simulations are performed considering a model porous structure that is approximated by a 3D cubical scaffold with cylindrical struts. The effect of the porosity and the equilibrium contact angle (between the gas-liquid interface and the solid struts) on the spreading behavior, liquid imbibition, and apparent contact angle (between the gas-liquid interface and the porous base) are studied. We also perform several simulations for droplet spreading on a flat surface as a reference case. Gas-liquid systems of the Laplace number, La = 45 and La = 144 × 103 are considered neglecting the effect of gravity. We report the time exponent (n) and pre-factor (C) of the power law describing the evolution of the spreading diameter (S = Ctn) for different equilibrium contact angles and porosity. Our simulations reveal that the apparent or macroscopic contact angle varies linearly with the equilibrium contact angle and increases with porosity. Not necessarily for all the wetting porous structures, a continuous capillary drainage occurs, and we find that the rate of the capillary drainage very much depends on the fluid inertia. At La = 144 × 103, numerically we capture the capillary wave induced pinch-off and daughter droplet ejection. We observe that on the porous structure the pinch-off is weak compared to that on a flat plate.

Effects of interaural time differences in fine structure and envelope on lateral discrimination in electric hearing.

PubMed

Majdak, Piotr; Laback, Bernhard; Baumgartner, Wolf-Dieter

2006-10-01

Bilateral cochlear implant (CI) listeners currently use stimulation strategies which encode interaural time differences (ITD) in the temporal envelope but which do not transmit ITD in the fine structure, due to the constant phase in the electric pulse train. To determine the utility of encoding ITD in the fine structure, ITD-based lateralization was investigated with four CI listeners and four normal hearing (NH) subjects listening to a simulation of electric stimulation. Lateralization discrimination was tested at different pulse rates for various combinations of independently controlled fine structure ITD and envelope ITD. Results for electric hearing show that the fine structure ITD had the strongest impact on lateralization at lower pulse rates, with significant effects for pulse rates up to 800 pulses per second. At higher pulse rates, lateralization discrimination depended solely on the envelope ITD. The data suggest that bilateral CI listeners benefit from transmitting fine structure ITD at lower pulse rates. However, there were strong interindividual differences: the better performing CI listeners performed comparably to the NH listeners.

Flow unit modeling and fine-scale predicted permeability validation in Atokan sandstones: Norcan East Kansas

USGS Publications Warehouse

Bhattacharya, S.; Byrnes, A.P.; Watney, W.L.; Doveton, J.H.

2008-01-01

Characterizing the reservoir interval into flow units is an effective way to subdivide the net-pay zone into layers for reservoir simulation. Commonly used flow unit identification techniques require a reliable estimate of permeability in the net pay on a foot-by-foot basis. Most of the wells do not have cores, and the literature is replete with different kinds of correlations, transforms, and prediction methods for profiling permeability in pay. However, for robust flow unit determination, predicted permeability at noncored wells requires validation and, if necessary, refinement. This study outlines the use o f a spreadsheet-based permeability validation technique to characterize flow units in wells from the Norcan East field, Clark County, Kansas, that produce from Atokan aged fine- to very fine-grained quartzarenite sandstones interpreted to have been deposited in brackish-water, tidally dominated restricted tidal-flat, tidal-channel, tidal-bar, and estuary bay environments within a small incised-valley-fill system. The methodology outlined enables the identification of fieldwide free-water level and validates and refines predicted permeability at 0.5-ft (0.15-m) intervals by iteratively reconciling differences in water saturation calculated from wire-line log and a capillary-pressure formulation that models fine- to very fine-grained sandstone with diagenetic clay and silt or shale laminae. The effectiveness of this methodology was confirmed by successfully matching primary and secondary production histories using a flow unit-based reservoir model of the Norcan East field without permeability modifications. The methodologies discussed should prove useful for robust flow unit characterization of different kinds of reservoirs. Copyright ?? 2008. The American Association of Petroleum Geologists. All rights reserved.

GEOLOGIC ASPECTS OF TIGHT GAS RESERVOIRS IN THE ROCKY MOUNTAIN REGION.

USGS Publications Warehouse

Spencer, Charles W.

1985-01-01

The authors describe some geologic characteristics of tight gas reservoirs in the Rocky Mountain region. These reservoirs usually have an in-situ permeability to gas of 0. 1 md or less and can be classified into four general geologic and engineering categories: (1) marginal marine blanket, (2) lenticular, (3) chalk, and (4) marine blanket shallow. Microscopic study of pore/permeability relationships indicates the existence of two varieties of tight reservoirs. One variety is tight because of the fine grain size of the rock. The second variety is tight because the rock is relatively tightly cemented and the pores are poorly connected by small pore throats and capillaries.

Hair combing to collect organic gunshot residues (OGSR).

PubMed

MacCrehan, William A; Layman, Malinda J; Secl, Janelle D

2003-08-12

A protocol is presented for the collection and analysis of gunshot residues (GSR) from hair. A fine-toothed comb is used for collection of the residues. A small zip-closure bag serves as a container for both sample storage and extraction of the characteristic organic powder additives. The success of this residue recovery approach was tested on simulated shooters and victims using mannequin-supported human wig hair as well as on human shooters. Residues were collected from four weapons: a revolver and semi-automatic pistol, rifle and shotgun. One characteristic additive, nitroglycerin, was detected by capillary electrophoresis (CE) in the majority of the collection experiments.

On the Physics of Fizziness: How liquid properties control bursting bubble aerosol production?

NASA Astrophysics Data System (ADS)

Ghabache, Elisabeth; Antkowiak, Arnaud; Josserand, Christophe; Seon, Thomas

2014-11-01

Either in a champagne glass or at the oceanic scales, the tiny capillary bubbles rising at the surface burst in ejecting myriads of droplets. Focusing on the ejected droplets produced by a single bubble, we investigate experimentally how liquid properties and bubble size affect their characteristics: number, ejection velocities, sizes and ejection heights. These results allow us to finely tune the bursting bubble aerosol production. In the context of champagne industry, aerosols play a major role by spreading wine aroma above the glass. We demonstrate that this champagne fizz can be enhanced by selecting the wine viscosity and the bubble size, thanks to specially designed glass.

Fast-acting self-healing metallic fuse.

NASA Technical Reports Server (NTRS)

Schwartz, F. C.; Renton, C. A.; Rabinovici, B.

1971-01-01

Description of a fast-acting nonmechanical self-healing mercury fuse capable of protecting a high current circuit or device from overcurrent fault damages. Basically the self-healing fuse consists of two enclosed mercury reservoirs connected by a fine capillary tube filled with mercury that serves as the fusing element. It is pointed out that a better understanding of the energy conversion process involved in the operation of the device could help explore other device configurations (such as a tapering geometry and use of magnetic field to drive the arc into the fuse wall on inductive loads, etc.) and thus extend the range of capabilities for this type of protective device.

3D Printing by Multiphase Silicone/Water Capillary Inks.

PubMed

Roh, Sangchul; Parekh, Dishit P; Bharti, Bhuvnesh; Stoyanov, Simeon D; Velev, Orlin D

2017-08-01

3D printing of polymers is accomplished easily with thermoplastics as the extruded hot melt solidifies rapidly during the printing process. Printing with liquid polymer precursors is more challenging due to their longer curing times. One curable liquid polymer of specific interest is polydimethylsiloxane (PDMS). This study demonstrates a new efficient technique for 3D printing with PDMS by using a capillary suspension ink containing PDMS in the form of both precured microbeads and uncured liquid precursor, dispersed in water as continuous medium. The PDMS microbeads are held together in thixotropic granular paste by capillary attraction induced by the liquid precursor. These capillary suspensions possess high storage moduli and yield stresses that are needed for direct ink writing. They could be 3D printed and cured both in air and under water. The resulting PDMS structures are remarkably elastic, flexible, and extensible. As the ink is made of porous, biocompatible silicone that can be printed directly inside aqueous medium, it can be used in 3D printed biomedical products, or in applications such as direct printing of bioscaffolds on live tissue. This study demonstrates a number of examples using the high softness, elasticity, and resilience of these 3D printed structures. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Capillary electrophoretic study of dibasic acids of different structures: Relation to separation of oxidative intermediates in remediation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yu, Z.; Cocke, D.L.

Dicarboxylic acids are important in environmental chemistry because they are intermediates in oxidative processes involved in natural remediation and waste management processes such as oxidative detoxification and advanced oxidation. Capillary electrophoresis (CE), a promising technique for separating and analyzing these intermediates, has been used to examine a series of dibasic acids of different structures and conformations. This series includes malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, maleic acid, fumaric acid, phthalic acid, and trans, trans-muconic acid. The CE parameters as well as structural variations (molecular structure and molecular isomers, buffer composition, pH, applied voltage, injection mode, current,more » temperature, and detection wavelength) that affect the separations and analytical results have been examined in this study. Those factors that affect the separation have been delineated. Among these parameters, the pH has been found to be the most important, which affects the double-layer of the capillary wall, the electro-osmotic flow and analyte mobility. The optimum pH for separating these dibasic acids, as well as the other parameters are discussed in detail and related to the development of methods for analyzing oxidation intermediates in oxidative waste management procedures.« less

Elastocapillarity: When Surface Tension Deforms Elastic Solids

NASA Astrophysics Data System (ADS)

Bico, José; Reyssat, Étienne; Roman, Benoît

2018-01-01

Although negligible at large scales, capillary forces may become dominant for submillimetric objects. Surface tension is usually associated with the spherical shape of small droplets and bubbles, wetting phenomena, imbibition, or the motion of insects at the surface of water. However, beyond liquid interfaces, capillary forces can also deform solid bodies in their bulk, as observed in recent experiments with very soft gels. Capillary interactions, which are responsible for the cohesion of sandcastles, can also bend slender structures and induce the bundling of arrays of fibers. Thin sheets can spontaneously wrap liquid droplets within the limit of the constraints dictated by differential geometry. This review aims to describe the different scaling parameters and characteristic lengths involved in elastocapillarity. We focus on three main configurations, each characterized by a specific dimension: three-dimensional (3D), deformations induced in bulk solids; 1D, bending and bundling of rod-like structures; and 2D, bending and stretching of thin sheets. Although each configuration deserves a detailed review, we hope our broad description provides a general view of elastocapillarity.

Self-assembly of triangular particles via capillary interactions

NASA Astrophysics Data System (ADS)

Bedi, Deshpreet; Zhou, Shangnan; Ferrar, Joseph; Solomon, Michael; Mao, Xiaoming

Colloidal particles adsorbed to a fluid interface deform the interface around them, resulting in either attractive or repulsive forces mediated by the interface. In particular, particle shape and surface roughness can produce an undulating contact line, such that the particles will assume energetically-favorable relative orientations and inter-particle distances to minimize the excess interfacial surface area. By expediently selecting specific particle shapes and associated design parameters, capillary interactions can be utilized to promote self-assembly of these particles into extended regular open structures, such as the kagome lattice, which have novel mechanical properties. We present the results of numerical simulations of equilateral triangle microprisms at an interface, including individually and in pairs. We show how particle bowing can yield two distinct binding events and connect it to theory in terms of a capillary multipole expansion and also to experiment, as presented in an accompanying talk. We also discuss and suggest design principles that can be used to create desirable open structures.

Capillary transport of water through textile-reinforced concrete applied in repairing and/or strengthening cracked RC structures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lieboldt, M.; Mechtcherine, V., E-mail: mechtcherine@tu-dresden.de

2013-10-15

The use of textile-reinforced concrete (TRC) has great potential for innovative solutions in repairing, protecting, and strengthening concrete and RC structures. The article at hand reports on an investigation on composite concrete specimens made of cracked ordinary concrete as substrate and textile-reinforced concrete (TRC) as a cover layer for its strengthening and repair. The TRC cover layer was assessed with regard to its effectiveness as a protective layer against the ingress of water through capillary action. Since in real applications such TRC layers may be cracked or presumed to be so, thereby activating the load-carrying function of the textile reinforcement,more » the TRC layer was cracked for purposes of this study. The water transport in the cracked ordinary concrete specimens without the TRC layer was used as a reference. Gravimetric measurements and neutron radiography served as the testing techniques. In ordinary concrete quick and deep ingress of water through relatively wide macro-cracks of approximately 100 μm width, followed by transport through the capillary pore system, caused saturation of large areas in a rather short time. TRC applied to the RC surface reduced the ingress of water to a large extent. Its small crack widths of 15 to 20 μm changed suction behaviour fundamentally. In the cracked substrate of ordinary concrete, capillary suction was prevented, and transport through the pore system of the matrix became the prevailing transport mechanism of capillary action. Not only was the mechanism altered, but the transport of water deep into inner regions was markedly retarded as well.« less

Quantitative twoplex glycan analysis using 12C6 and 13C6 stable isotope 2-aminobenzoic acid labelling and capillary electrophoresis mass spectrometry.

PubMed

Váradi, Csaba; Mittermayr, Stefan; Millán-Martín, Silvia; Bones, Jonathan

2016-12-01

Capillary electrophoresis (CE) offers excellent efficiency and orthogonality to liquid chromatographic (LC) separations for oligosaccharide structural analysis. Combination of CE with high resolution mass spectrometry (MS) for glycan analysis remains a challenging task due to the MS incompatibility of background electrolyte buffers and additives commonly used in offline CE separations. Here, a novel method is presented for the analysis of 2-aminobenzoic acid (2-AA) labelled glycans by capillary electrophoresis coupled to mass spectrometry (CE-MS). To ensure maximum resolution and excellent precision without the requirement for excessive analysis times, CE separation conditions including the concentration and pH of the background electrolyte, the effect of applied pressure on the capillary inlet and the capillary length were evaluated. Using readily available 12/13 C 6 stable isotopologues of 2-AA, the developed method can be applied for quantitative glycan profiling in a twoplex manner based on the generation of extracted ion electropherograms (EIE) for 12 C 6 'light' and 13 C 6 'heavy' 2-AA labelled glycan isotope clusters. The twoplex quantitative CE-MS glycan analysis platform is ideally suited for comparability assessment of biopharmaceuticals, such as monoclonal antibodies, for differential glycomic analysis of clinical material for potential biomarker discovery or for quantitative microheterogeneity analysis of different glycosylation sites within a glycoprotein. Additionally, due to the low injection volume requirements of CE, subsequent LC-MS analysis of the same sample can be performed facilitating the use of orthogonal separation techniques for structural elucidation or verification of quantitative performance.

A two scale modeling and computational framework for vibration-induced Raynaud syndrome.

PubMed

Hua, Yue; Lemerle, Pierre; Ganghoffer, Jean-François

2017-07-01

Hand-Arm Vibration syndrome (HAVS), usually caused by long-term use of hand-held power tools, can in certain manifestations alter the peripheral blood circulation in the hand-arm region. HAVS typically occurs after exposure to cold, causing an abnormally strong vasoconstriction of blood vessels. A pathoanatomical mechanism suggests that a reduction of the lumen of the blood vessels in VWF (Vibration White Finger) subjects, due to either hypertrophy or thickening of the vessel wall, may be at the origin of the disease. However, the direct and indirect effects of the load of the hand-held tools on the structure of blood vessels remain controversial:.one hypothesis is the mechanical action of vibration on the local acral dysregulation and/or on the vessel histomorphological modifications. Another hypothesis is the participation of the sympathetic nervous system to this dysregulation. In this paper, we assume the modifications as mechanobiological growth and the load-effect relationship may be interpreted as directly or indirectly induced. This work is the first attempt to model the effect of vibration through soft tissues onto the distal capillaries, addressing the double paradigm of multi space-time scales, i.e. low period vibration versus high time constant of the growth phenomenon as well as vibrations propagating in the macroscopic tissue including the microscopic capillary structures subjected to a pathological microstructural evolution. The objective is to lay down the theoretical basis of growth modeling for the small distal artery, with the ability to predict the geometrical and structural changes of the arterial walls caused by vibration exposure. We adopt the key idea of splitting the problem into one global vibration problem at the macroscopic scale and one local growth problem at the micro level. The macroscopic hyperelastic viscous dynamic model of the fingertip cross-section is validated by fitting experimental data. It is then used in steady-state vibration conditions to predict the mechanical fields in the close vicinity of capillaries. The space scale transfer from macroscopic to microscopic levels is ensured by considering a representative volume element (RVE) embedding a single capillary in its center. The vibrations emitted by the hand held power tool are next linked to the capillary growth through the adopted biomechanical growth model at the capillary level. The obtained results show that vibrations induce an increase of the thickness of the capillary's wall, thereby confirming the scenario of vibrations induced reduction of the lumen of blood vessels. Copyright © 2017 Elsevier Ltd. All rights reserved.

[The role of temporal fine structure in tone recognition and music perception].

PubMed

Zhou, Q; Gu, X; Liu, B

2017-11-07

The sound signal can be decomposed into temporal envelope and temporal fine structure information. The temporal envelope information is crucial for speech perception in quiet environment, and the temporal fine structure information plays an important role in speech perception in noise, Mandarin tone recognition and music perception, especially the pitch and melody perception.

Willis Lamb, Jr., the Hydrogen Atom, and the Lamb Shift

Science.gov Websites

1955, Lamb won the Nobel Prize in Physics for his discoveries concerning "the fine structure of , May 7 - September 30, 1979 Fine Structure of the Hydrogen Atom, Part I; Part II; Part III; Part IV ; Part V; Part VI (from Physical Review 1950-1953) Microwave Technique for Determining the Fine Structure

Impact of maternal diabetes type 1 on proliferative potential, differentiation and apoptotic activity in villous capillaries of term placenta.

PubMed

Jirkovská, Marie; Kučera, Tomáš; Dvořáková, Veronika; Jadrníček, Martin; Moravcová, Milena; Žižka, Zdeněk; Krejčí, Vratislav

2016-04-01

Maternal diabetes mellitus changes morphology and impairs function of placental capillaries. Here, quantitative parameters characterizing cell proliferation using detection of Ki67, differentiation reflected by nestin expression and apoptosis in placental capillary bed with active caspase 3 as a marker were compared in normal term placentas and placentas from pregnancies complicated by Type 1 maternal diabetes mellitus. Specimens of sixteen diabetic placentas and eight control placentas were collected by systematic uniform random sampling. Immunohistochemical detections of Ki67, nestin, and active caspase 3 were performed in histological sections of five haphazardly chosen blocks per placenta. Twenty fields of view per section, i.e. one hundred fields of view per placenta, were used for analysis of proliferation as well as of apoptosis, and in approximately 70 capillary cross-sections per placenta the nestin-positive segments of their circumference were measured. The percentage of Ki67-positive cells counted in the capillary wall was significantly lower in diabetic group. The counts of Ki67-labelled nuclei per villous area unit were significantly lower in cytotrophoblast and capillary wall of terminal villi in diabetic placenta. The proportion of nestin-labeled segments of capillary circumference was significantly higher in placentas of diabetic group. No differences in the numbers of apoptotic cells were found between studied groups. The results show that the term placenta in Type 1 diabetes has lower potential to enlarge the surface area of structures involved in maternofetal transport, and that the villous capillary bed displays delayed differentiation. Those factors may participate in decreased ability of diabetic placenta to comply with fetal requirements in the final stage of pregnancy. Copyright © 2016 Elsevier Ltd. All rights reserved.

In situ data collection and structure refinement from microcapillary protein crystallization

PubMed Central

Yadav, Maneesh K.; Gerdts, Cory J.; Sanishvili, Ruslan; Smith, Ward W.; Roach, L. Spencer; Ismagilov, Rustem F.; Kuhn, Peter; Stevens, Raymond C.

2007-01-01

In situ X-ray data collection has the potential to eliminate the challenging task of mounting and cryocooling often fragile protein crystals, reducing a major bottleneck in the structure determination process. An apparatus used to grow protein crystals in capillaries and to compare the background X-ray scattering of the components, including thin-walled glass capillaries against Teflon, and various fluorocarbon oils against each other, is described. Using thaumatin as a test case at 1.8 Å resolution, this study demonstrates that high-resolution electron density maps and refined models can be obtained from in situ diffraction of crystals grown in microcapillaries. PMID:17468785

Role of the sedimentary structure of the urban vadose zone (URVAZO) on the transfer of heavy metals of an urban stormwater basin

NASA Astrophysics Data System (ADS)

Angulo-Jaramillo, R.; Winiarski, T.; Goutaland, D.; Lassabatere, L.

2009-12-01

Stormwater infiltration basins have become a common alternative practice to traditional stormwater pipe networks in urban areas. They are often built in permeable subsurface soils (Urban Vadose Zone, URVAZO), such as alluvial deposits. These sedimentary deposits are highly heterogeneous and generate preferential flow paths that may cause either rapid or non-uniform transport of contaminants at great depths. The understanding of how subsurface vadose zone heterogeneities transfer contaminant and fluid flow to the aquifer still remains a challenge in urban hydrology. Indeed, urban stormwater may contain pollutants that can contaminate either soil or groundwater. The aim of this study is to evaluate the role of the lithological heterogeneity of a glaciofluvial deposit underlying an urban infiltration basin on the link between water flow and heavy metals retention. A trench wall (14m length x 3m depth) was exposed by excavating the glaciofluvial formation. By a hydrogeophysical approach based on a sedimentary structural units and in situ hydraulic characterization (Beerkan tests), a realistic hydrostratigraphic 2D model was defined. The trench was sampled on nine vertical sections of 1.5m length, with ten samples per vertical section following each lithofacies. A total of 90 samples were analyzed. Coarse (mechanical sieving) and fine (laser diffraction) particle size distribution analysis, as well as the concentration of three replicates of Pb, Cu, Zn and organic matter (OM) was measured for each sample. The principal component analysis shows a strong correlation between metal concentration and the lithofacies. This hydrostratigraphic model was implemented in the finite element program Hydrus2D. The soil heterogeneity exerts an impact on the heterogeneity of the water content field under slightly saturated conditions, as they induce capillary barrier effects. These capillary barrier effects may generate water accumulation in some lithofacies overlying matrix-free gravel; they lead to lateral flow patterns known as funneled flows. Knowledge of the geometry (orientation, dip) at the structural scale is therefore a prerequisite for evaluating the preferential flow paths. They can explain that the silt fraction may come from colloidal migration through the vadose zone. The use of coupled water-geochemical transfer models enables us to advance assumptions helping the comprehension of principal hydrogeochemical process in the urban vadose zone.

Dynamic Mechanical Properties and Microstructure of Graphene Oxide Nanosheets Reinforced Cement Composites.

PubMed

Long, Wu-Jian; Wei, Jing-Jie; Ma, Hongyan; Xing, Feng

2017-11-24

This paper presents an experimental investigation on the effect of uniformly dispersed graphene oxide (GO) nanosheets on dynamic mechanical properties of cement based composites prepared with recycled fine aggregate (RFA). Three different amounts of GO, 0.05%, 0.10%, and 0.20% in mass of cement, were used in the experiments. The visual inspections of GO nanosheets were also carried out after ultrasonication by transmission electron microscope (TEM) atomic force microscope (AFM), and Raman to characterize the dispersion effect of graphite oxide. Dynamic mechanical analyzer test showed that the maximum increased amount of loss factor and storage modulus, energy absorption was 125%, 53%, and 200% when compared to the control sample, respectively. The flexural and compressive strengths of GO-mortar increased up to 22% to 41.3% and 16.2% to 16.4% with 0.20 wt % GO at 14 and 28 days, respectively. However the workability decreased by 7.5% to 18.8% with 0.05% and 0.2% GO addition. Microstructural analysis with environmental scanning electron microscopy (ESEM)/backscattered mode (BSEM) showed that the GO-cement composites had a much denser structure and better crystallized hydration products, meanwhile mercury intrusion porosimetry (MIP) testing and image analysis demonstrated that the incorporation of GO in the composites can help in refining capillary pore structure and reducing the air voids content.

Dynamic Mechanical Properties and Microstructure of Graphene Oxide Nanosheets Reinforced Cement Composites

PubMed Central

Wei, Jing-Jie; Xing, Feng

2017-01-01

This paper presents an experimental investigation on the effect of uniformly dispersed graphene oxide (GO) nanosheets on dynamic mechanical properties of cement based composites prepared with recycled fine aggregate (RFA). Three different amounts of GO, 0.05%, 0.10%, and 0.20% in mass of cement, were used in the experiments. The visual inspections of GO nanosheets were also carried out after ultrasonication by transmission electron microscope (TEM) atomic force microscope (AFM), and Raman to characterize the dispersion effect of graphite oxide. Dynamic mechanical analyzer test showed that the maximum increased amount of loss factor and storage modulus, energy absorption was 125%, 53%, and 200% when compared to the control sample, respectively. The flexural and compressive strengths of GO-mortar increased up to 22% to 41.3% and 16.2% to 16.4% with 0.20 wt % GO at 14 and 28 days, respectively. However the workability decreased by 7.5% to 18.8% with 0.05% and 0.2% GO addition. Microstructural analysis with environmental scanning electron microscopy (ESEM)/backscattered mode (BSEM) showed that the GO-cement composites had a much denser structure and better crystallized hydration products, meanwhile mercury intrusion porosimetry (MIP) testing and image analysis demonstrated that the incorporation of GO in the composites can help in refining capillary pore structure and reducing the air voids content. PMID:29186810

Moisture harvesting and water transport through specialized micro-structures on the integument of lizards

PubMed Central

Comanns, Philipp; Effertz, Christian; Hischen, Florian; Staudt, Konrad; Böhme, Wolfgang

2011-01-01

Summary Several lizard species that live in arid areas have developed special abilities to collect water with their bodies' surfaces and to ingest the so collected moisture. This is called rain- or moisture-harvesting. The water can originate from air humidity, fog, dew, rain or even from humid soil. The integument (i.e., the skin plus skin derivatives such as scales) has developed features so that the water spreads and is soaked into a capillary system in between the reptiles' scales. Within this capillary system the water is transported to the mouth where it is ingested. We have investigated three different lizard species which have developed the ability for moisture harvesting independently, viz. the Australian thorny devil (Moloch horridus), the Arabian toadhead agama (Phrynocephalus arabicus) and the Texas horned lizard (Phrynosoma cornutum). All three lizards have a honeycomb like micro ornamentation on the outer surface of the scales and a complex capillary system in between the scales. By investigation of individual scales and by producing and characterising polymer replicas of the reptiles' integuments, we found that the honeycomb like structures render the surface superhydrophilic, most likely by holding a water film physically stable. Furthermore, the condensation of air humidity is improved on this surface by about 100% in comparison to unstructured surfaces. This allows the animals to collect moisture with their entire body surface. The collected water is transported into the capillary system. For Phrynosoma cornutum we found the interesting effect that, in contrast to the other two investigated species, the water flow in the capillary system is not uniform but directed to the mouth. Taken together we found that the micro ornamentation yields a superhydrophilic surface, and the semi-tubular capillaries allow for an efficient passive – and for Phrynosoma directed – transport of water. PMID:21977432

Capillary zone electrophoresis-mass spectrometer interface

DOEpatents

D`Silva, A.

1996-08-06

A device for providing equal electrical potential between two loci unconnected by solid or liquid electrical conductors is provided. The device comprises a first electrical conducting terminal, a second electrical conducting terminal connected to the first terminal by a rigid dielectric structure, and an electrically conducting gas contacting the first and second terminals. This device is particularly suitable for application in the electrospray ionization interface between a capillary zone electrophoresis apparatus and a mass spectrometer. 1 fig.

Capillary zone electrophoresis-mass spectrometer interface

DOEpatents

D'Silva, Arthur

1996-08-06

A device for providing equal electrical potential between two loci unconnected by solid or liquid electrical conducts is provided. The device comprises a first electrical conducting terminal, a second electrical conducting terminal connected to the first terminal by a rigid dielectric structure, and an electrically conducting gas contacting the first and second terminals. This device is particularly suitable for application in the electrospray ionization interface between a capillary zone electrophoresis apparatus and a mass spectrometer.

Statistical Fine Structure in the Inhomogeneously Broadened Electronic Origin of Pentacene in p-Terphenyl.

DTIC Science & Technology

1988-01-29

Electronic Origin of Pentacene in p-Terphenyl by T. P. Carter, M. Manavi, and W. E. Moerner Prepared for Publication inDTIC Journal of Chemical Physics...Classification) Statistical Fine Structure in the Inhomogeneously Broadened Electronic Origin of Pentacene in p-Terphenyl 12. PERSONAL AUTHOR(S) T. P...of pentacene in p-terphenyl using laser FM spectroscopy. Statistical fine structure is time-independent structure on the inhomogeneous line caused by

Statistical Fine Structure of Inhomogeneously Broadened Absorption Lines.

DTIC Science & Technology

1987-07-31

inhomogeneously broadened optical absorption of pentacene n p-terphenyl at liquid helium temperatures... SFS is the actual frequency- ependent, time...statistical fine structure (SFS) in the inhomogeneously broadened optical absorption of pentacene in p-terphenyl at liquid helium temperatures. SFS is the...quite difficult . -2- We have observed for the first time statistical fine structure in the inhomogeneously broadened optical absorption of pentacene

In situ preparation of multilayer coated capillary column with HKUST-1 for separation of neutral small organic molecules by open tubular capillary electrochromatography.

PubMed

Xu, Yin-Yin; Lv, Wen-Juan; Ren, Cui-Ling; Niu, Xiao-Ying; Chen, Hong-Li; Chen, Xing-Guo

2018-01-12

The popularity of novel nanoparticles coated capillary column has aroused widespread attention of researchers. Metal organic frameworks (MOFs) with special structure and chemical properties have received great interest in separation sciences. This work presents the investigation of HKUST-1 (Hong Kong University of Science and Technology-1, called Cu 3 (BTC) 2 or MOF-199) nanoparticles as a new type of coating material for capillary electrochromatography. For the first time, three layers coating (3-LC), five layers coating (5-LC), ten layers coating (10-LC), fifteen layers coating (15-LC), twenty layers coating(20-LC) and twenty-five layers coating (25-LC) capillary columns coated with HKUST-1 nanoparticles were synthesized by covalent bond with in situ, layer-by-layer self-assembly approach. The results of scanning electron microscopy (SEM), X-ray diffraction (XRD) and plasma atomic emission spectrometry (ICP-AES) indicated that HKUST-1 was successfully grafted on the inner wall of the capillary. The separating performances of 3-LC, 5-LC, 10-LC, 15-LC, 20-LC and 25-LC open tubular (OT) capillary columns were studied with some neutral small organic molecules. The results indicated that the neutral small organic molecules were separated successfully with 10-LC, 15-LC and 20-LC OT capillary columns because of the size selectivity of lattice aperture and hydrophobicity of organic ligands. In addition, 10-LC and 15-LC OT capillary columns showed better performance for the separation of certain phenolic compounds. Furthermore, 10-LC, 15-LC and 20-LC OT capillary columns exhibited good intra-day repeatability with the relative standard deviations (RSDs; %) of migration time and peak areas lying in the range of 0.3-1.2% and 0.5-4.2%, respectively. For inter-day reproducibility, the RSDs of the three OT capillary columns were found to be lying in the range of 0.3-5.5% and 0.3-4.5% for migration time and peak area, respectively. The RSDs of retention times for column-to-column for three batches of 10-LC, 15-LC and 20-LC OT capillary columns were in the range from 2.3% to 7.2%. Moreover, the fabricated 10-LC, 15-LC and 20-LC OT capillary columns exhibited good repeatability and stability for separation, which could be used successively for more than 120 runs with no observable changes on the separation efficiency. Copyright © 2017 Elsevier B.V. All rights reserved.

Evaluation of SHM system produced by additive manufacturing via acoustic emission and other NDT methods.

PubMed

Strantza, Maria; Aggelis, Dimitrios G; de Baere, Dieter; Guillaume, Patrick; van Hemelrijck, Danny

2015-10-21

During the last decades, structural health monitoring (SHM) systems are used in order to detect damage in structures. We have developed a novel structural health monitoring approach, the so-called "effective structural health monitoring" (eSHM) system. The current SHM system is incorporated into a metallic structure by means of additive manufacturing (AM) and has the possibility to advance life safety and reduce direct operative costs. It operates based on a network of capillaries that are integrated into an AM structure. The internal pressure of the capillaries is continuously monitored by a pressure sensor. When a crack nucleates and reaches the capillary, the internal pressure changes signifying the existence of the flaw. The main objective of this paper is to evaluate the crack detection capacity of the eSHM system and crack location accuracy by means of various non-destructive testing (NDT) techniques. During this study, detailed acoustic emission (AE) analysis was applied in AM materials for the first time in order to investigate if phenomena like the Kaiser effect and waveform parameters used in conventional metals can offer valuable insight into the damage accumulation of the AM structure as well. Liquid penetrant inspection, eddy current and radiography were also used in order to confirm the fatigue damage and indicate the damage location on un-notched four-point bending AM metallic specimens with an integrated eSHM system. It is shown that the eSHM system in combination with NDT can provide correct information on the damage condition of additive manufactured metals.

Evaluation of SHM System Produced by Additive Manufacturing via Acoustic Emission and Other NDT Methods

PubMed Central

Strantza, Maria; Aggelis, Dimitrios G.; de Baere, Dieter; Guillaume, Patrick; van Hemelrijck, Danny

2015-01-01

During the last decades, structural health monitoring (SHM) systems are used in order to detect damage in structures. We have developed a novel structural health monitoring approach, the so-called “effective structural health monitoring” (eSHM) system. The current SHM system is incorporated into a metallic structure by means of additive manufacturing (AM) and has the possibility to advance life safety and reduce direct operative costs. It operates based on a network of capillaries that are integrated into an AM structure. The internal pressure of the capillaries is continuously monitored by a pressure sensor. When a crack nucleates and reaches the capillary, the internal pressure changes signifying the existence of the flaw. The main objective of this paper is to evaluate the crack detection capacity of the eSHM system and crack location accuracy by means of various non-destructive testing (NDT) techniques. During this study, detailed acoustic emission (AE) analysis was applied in AM materials for the first time in order to investigate if phenomena like the Kaiser effect and waveform parameters used in conventional metals can offer valuable insight into the damage accumulation of the AM structure as well. Liquid penetrant inspection, eddy current and radiography were also used in order to confirm the fatigue damage and indicate the damage location on un-notched four-point bending AM metallic specimens with an integrated eSHM system. It is shown that the eSHM system in combination with NDT can provide correct information on the damage condition of additive manufactured metals. PMID:26506349

Electromagnetic liquid pistons for capillarity-based pumping.

PubMed

Malouin, Bernard A; Vogel, Michael J; Olles, Joseph D; Cheng, Lili; Hirsa, Amir H

2011-02-07

The small scales associated with lab-on-a-chip technologies lend themselves well to capillarity-dominated phenomena. We demonstrate a new capillarity-dominated system where two adjoining ferrofluid droplets can behave as an electronically-controlled oscillator or switch by an appropriate balance of magnetic, capillary, and inertial forces. Their oscillatory motion can be exploited to displace a surrounding liquid (akin to an axial piston pump), forming electromagnetic "liquid pistons." Such ferrofluid pistons can pump a precise volume of liquid via finely tunable amplitudes (cf. pump stroke) or resonant frequencies (cf. pump speed) with no solid moving parts for long-term operation without wear in a small device. Furthermore, the rapid propagation of electromagnetic fields and the favorable scaling of capillary forces with size permit micron sized devices with very fast operating speeds (∼kHz). The pumping dynamics and performance of these liquid pistons is explored, with experimental measurements showing good agreement with a spherical cap model. While these liquid pistons may find numerous applications in micro- and mesoscale fluidic devices (e.g., remotely activated drug delivery), here we demonstrate the use of these liquid pistons in capillarity-dominated systems for chip-level, fast-acting adaptive liquid lenses with nearly perfect spherical interfaces.

Vascular development in the vertebrate pancreas.

PubMed

Azizoglu, D Berfin; Chong, Diana C; Villasenor, Alethia; Magenheim, Judith; Barry, David M; Lee, Simon; Marty-Santos, Leilani; Fu, Stephen; Dor, Yuval; Cleaver, Ondine

2016-12-01

The vertebrate pancreas is comprised of a highly branched tubular epithelium, which is intimately associated with an extensive and specialized vasculature. While we know a great deal about basic vascular anatomy of the adult pancreas, as well as islet capillaries, surprisingly little is known about the ontogeny of its blood vessels. Here, we analyze development of the pancreatic vasculature in the mouse embryo. We show that pancreatic epithelial branches intercalate with the fine capillary plexus of the surrounding pancreatic mesenchyme. Endothelial cells (ECs) within this mesenchyme are heterogeneous from the onset of organogenesis. Pancreatic arteries take shape before veins, in a manner analogous to early embryonic vessels. The main central artery forms during mid-gestation, as a result of vessel coalescence and remodeling of a vascular plexus. In addition, we show that vessels in the forming pancreas display a predictable architecture that is dependent on VEGF signaling. Over-expression of VEGF disrupts vascular patterning and arteriovenous differentiation within the developing pancreas. This study constitutes a first-time in-depth cellular and molecular characterization of pancreatic blood vessels, as they coordinately grow along with the pancreatic epithelium. Copyright © 2016 Elsevier Inc. All rights reserved.

Microemulsion Electrokinetic Chromatography.

PubMed

Buchberger, Wolfgang

2016-01-01

Microemulsion electrokinetic chromatography (MEEKC) is a special mode of capillary electrophoresis employing a microemulsion as carrier electrolyte. Analytes may partition between the aqueous phase of the microemulsion and its oil droplets which act as a pseudostationary phase. The technique is well suited for the separation of neutral species, in which case charged oil droplets (obtained by addition of an anionic or cationic surfactant) are present. A single set of separation parameters may be sufficient for separation of a wide range of analytes belonging to quite different chemical classes. Fine-tuning of resolution and analysis time may be achieved by addition of organic solvents, by changes in the nature of the surfactants (and cosurfactants) used to stabilize the microemulsion, or by various additives that may undergo some additional interactions with the analytes. Besides the separation of neutral analytes (which may be the most important application area of MEEKC), it can also be employed for cationic and/or anionic species. In this chapter, MEEKC conditions are summarized that have proven their reliability for routine analysis. Furthermore, the mechanisms encountered in MEEKC allow an efficient on-capillary preconcentration of analytes, so that the problem of poor concentration sensitivity of ultraviolet absorbance detection is circumvented.

The Fast and Non-capillary Fluid Filling Mechanism in the Hummingbird's Tongue

NASA Astrophysics Data System (ADS)

Rico-Guevara, Alejandro; Fan, Tai-Hsi; Rubega, Margaret

2014-03-01

Hummingbirds gather nectar by inserting their beaks inside flowers and cycling their tongues at a frequency of up to 20 Hz. It is unclear how they achieve efficiency at this high licking rate. Ever since proposed in 1833, it has been believed that hummingbird tongues are a pair of tiny straws filled with nectar by capillary rise. Our discoveries are very different from this general consensus. The tongue does not draw up floral nectar via capillary action under experimental conditions that resemble natural ones. Theoretical models based on capillary rise were mistaken and unsuitable for estimating the fluid intake rate and to support foraging theories. We filmed (up to 1265 frames/s) the fluid uptake in 20 species of hummingbirds that belong to 7 out of the 9 main hummingbird clades. We found that the fluid filling within the portions of the tongue that remain outside the nectar is about five times faster than capillary filling. We present strong evidence to rule out the capillarity model. We introduce a new fluid-structure interaction and hydrodynamic model and compare the results with field experimental data to explain how hummingbirds actually extract fluid from flowers at the lick level.

Underwater locomotion in a terrestrial beetle: combination of surface de-wetting and capillary forces

PubMed Central

Hosoda, Naoe; Gorb, Stanislav N.

2012-01-01

For the first time, we report the remarkable ability of the terrestrial leaf beetle Gastrophysa viridula to walk on solid substrates under water. These beetles have adhesive setae on their feet that produce a secretory fluid having a crucial role in adhesion on land. In air, adhesion is produced by capillary forces between the fluid-covered setae and the substrate. In general, capillary forces do not contribute to adhesion under water. However, our observations showed that these beetles may use air bubbles trapped between their adhesive setae to walk on flooded, inclined substrata or even under water. Beetle adhesion to hydrophilic surfaces under water was lower than that in air, whereas adhesion to hydrophobic surfaces under water was comparable to that in air. Oil-covered hairy pads had a pinning effect, retaining the air bubbles on their feet. Bubbles in contact with the hydrophobic substrate de-wetted the substrate and produced capillary adhesion. Additional capillary forces are generated by the pad's liquid bridges between the foot and the substrate. Inspired by this idea, we designed an artificial silicone polymer structure with underwater adhesive properties. PMID:22874756

Stereological Study on the Positive Effect of Running Exercise on the Capillaries in the Hippocampus in a Depression Model.

PubMed

Chen, Linmu; Zhou, Chunni; Tan, Chuanxue; Wang, Feifei; Gao, Yuan; Huang, Chunxia; Zhang, Yi; Jiang, Lin; Tang, Yong

2017-01-01

Running exercise is an effective method to improve depressive symptoms when combined with drugs. However, the underlying mechanisms are not fully clear. Cerebral blood flow perfusion in depressed patients is significantly lower in the hippocampus. Physical activity can achieve cerebrovascular benefits. The purpose of this study was to evaluate the impacts of running exercise on capillaries in the hippocampal CA1 and dentate gyrus (DG) regions. The chronic unpredictable stress (CUS) depression model was used in this study. CUS rats were given 4 weeks of running exercise from the fifth week to the eighth week (20 min every day from Monday to Friday each week). The sucrose consumption test was used to measure anhedonia. Furthermore, stereological methods were used to investigate the capillary changes among the control group, CUS/Standard group and CUS/Running group. Sucrose consumption significantly increased in the CUS/Running group. Running exercise has positive effects on the capillaries parameters in the hippocampal CA1 and DG regions, such as the total volume, total length and total surface area. These results demonstrated that capillaries are protected by running exercise in the hippocampal CA1 and DG might be one of the structural bases for the exercise-induced treatment of depression-like behavior. These results suggest that drugs and behavior influence capillaries and may be considered as a new means for depression treatment in the future.

P39-T Analysis of Oligosaccharides by Capillary-Scale High-Performance Anion-Exchange Chromatography with Pulsed Amperometric Detection (CHPAEC-PAD) and On-Line Electrospray-Ionization Ion-Trap Mass Spectrometry (CHPAEC-ITMS)

PubMed Central

Bruggink, C.; Koeleman, C.; Barreto, V.; Lui, Y.; Pohl, C.; Ingendoh, A.; Wuhrer, M.; Hokke, C.; Deelder, A.

2007-01-01

High-pH anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD) is an established technique for selective separation and analysis of underivatized carbohydrates. The miniaturization of chromatographic techniques by means of capillary columns, and on-line coupling to mass spectrometry are critical to the further development of glycan analysis methods that are compatible with the current requirements in clinical settings. A system has been developed based on the Dionex BioLC equipped with a microbore gradient pump with PEEK flow splitter, a FAMOS micro autosampler, a modified electrochemical cell for on-line capillary PAD, and a capillary column (380 μm i.d.) packed with a new type of anion-exchange resin. This system operates with sensitivity in the low femtomol range. In addition, an on-line capillary desalter has been developed to allow direct coupling to the Bruker Esquire 3000 ion-trap mass spectrometer with electrospray ionization interface (ESI-IT-MS). Both systems have been evaluated using oligosaccharide standards as well as urine samples exhibiting various lysosomal oligosaccharide storage diseases. Initial data indicate that the robust and selective anion-exchange system, in combination with ESI-IT-MS for structure confirmation and analysis, provides a powerful platform that complements existing nano/capillary LC-MS methods for analytical determination of oligosaccharides in biological matrices.

Interfacial gauge methods for incompressible fluid dynamics

DOE PAGES

Saye, R.

2016-06-10

Designing numerical methods for incompressible fluid flow involving moving interfaces, for example, in the computational modeling of bubble dynamics, swimming organisms, or surface waves, presents challenges due to the coupling of interfacial forces with incompressibility constraints. A class of methods, denoted interfacial gauge methods, is introduced for computing solutions to the corresponding incompressible Navier-Stokes equations. These methods use a type of "gauge freedom" to reduce the numerical coupling between fluid velocity, pressure, and interface position, allowing high-order accurate numerical methods to be developed more easily. Making use of an implicit mesh discontinuous Galerkin framework, developed in tandem with this work,more » high-order results are demonstrated, including surface tension dynamics in which fluid velocity, pressure, and interface geometry are computed with fourth-order spatial accuracy in the maximum norm. Applications are demonstrated with two-phase fluid flow displaying fine-scaled capillary wave dynamics, rigid body fluid-structure interaction, and a fluid-jet free surface flow problem exhibiting vortex shedding induced by a type of Plateau-Rayleigh instability. The developed methods can be generalized to other types of interfacial flow and facilitate precise computation of complex fluid interface phenomena.« less

Indian-Ink Perfusion Based Method for Reconstructing Continuous Vascular Networks in Whole Mouse Brain

PubMed Central

Xue, Songchao; Gong, Hui; Jiang, Tao; Luo, Weihua; Meng, Yuanzheng; Liu, Qian; Chen, Shangbin; Li, Anan

2014-01-01

The topology of the cerebral vasculature, which is the energy transport corridor of the brain, can be used to study cerebral circulatory pathways. Limited by the restrictions of the vascular markers and imaging methods, studies on cerebral vascular structure now mainly focus on either observation of the macro vessels in a whole brain or imaging of the micro vessels in a small region. Simultaneous vascular studies of arteries, veins and capillaries have not been achieved in the whole brain of mammals. Here, we have combined the improved gelatin-Indian ink vessel perfusion process with Micro-Optical Sectioning Tomography for imaging the vessel network of an entire mouse brain. With 17 days of work, an integral dataset for the entire cerebral vessels was acquired. The voxel resolution is 0.35×0.4×2.0 µm3 for the whole brain. Besides the observations of fine and complex vascular networks in the reconstructed slices and entire brain views, a representative continuous vascular tracking has been demonstrated in the deep thalamus. This study provided an effective method for studying the entire macro and micro vascular networks of mouse brain simultaneously. PMID:24498247

Field-Scale Modeling of Local Capillary Trapping During CO2 Injection into a Saline Aquifer

NASA Astrophysics Data System (ADS)

Ren, B.; Lake, L. W.; Bryant, S. L.

2015-12-01

Local capillary trapping is the small-scale (10-2 to 10+1 m) CO2 trapping that is caused by the capillary pressure heterogeneity. The benefit of LCT, applied specially to CO2 sequestration, is that saturation of stored CO2 is larger than the residual gas, yet these CO2 are not susceptible to leakage through failed seals. Thus quantifying the extent of local capillary trapping is valuable in design and risk assessment of geologic storage projects. Modeling local capillary trapping is computationally expensive and may even be intractable using a conventional reservoir simulator. In this paper, we propose a novel method to model local capillary trapping by combining geologic criteria and connectivity analysis. The connectivity analysis originally developed for characterizing well-to-reservoir connectivity is adapted to this problem by means of a newly defined edge weight property between neighboring grid blocks, which accounts for the multiphase flow properties, injection rate, and gravity effect. Then the connectivity is estimated from shortest path algorithm to predict the CO2 migration behavior and plume shape during injection. A geologic criteria algorithm is developed to estimate the potential local capillary traps based only on the entry capillary pressure field. The latter is correlated to a geostatistical realization of permeability field. The extended connectivity analysis shows a good match of CO2 plume computed by the full-physics simulation. We then incorporate it into the geologic algorithm to quantify the amount of LCT structures identified within the entry capillary pressure field that can be filled during CO2 injection. Several simulations are conducted in the reservoirs with different level of heterogeneity (measured by the Dykstra-Parsons coefficient) under various injection scenarios. We find that there exists a threshold Dykstra-Parsons coefficient, below which low injection rate gives rise to more LCT; whereas higher injection rate increases LCT in heterogeneous reservoirs. Both the geologic algorithm and connectivity analysis are very fast; therefore, the integrated methodology can be used as a quick tool to estimate local capillary trapping. It can also be used as a potential complement to the full-physics simulation to evaluate safe storage capacity.

Numerical modeling of fluid and oxygen exchanges through microcirculation for the assessment of microcirculation alterations caused by type 2 diabetes.

PubMed

Tang, Yuanliang; He, Ying

2018-05-01

Type 2 diabetes mellitus (DM2) is frequently accompanied by microcirculation complications, including structural and functional alterations, which may have serious effects on substance exchanges between blood and interstitial tissue and the health of organs. In this paper, we aim to study the influence of microcirculation alterations in DM2 patients on fluid and oxygen exchanges through a model analysis. A fluid flow and oxygen transport model were developed by considering the interplay between blood in capillary network and interstitial tissue. The two regions were separately represented by 1D network model and 3D volume model, and the immersed boundary method (IBM) was adopted to solve fluid and mass transfer between these two regions. By using the model, the steady flow field and the distributions of oxygen in capillary network and surrounding tissue were firstly simulated. In the interstitial volume, fluid pressure and oxygen tension decreased with the increase of distance from the network; in the network, oxygen tension in blood plasma dropped from 100 mm Hg at the entrance to about 40 mm Hg at the exit. We further tested several structural and functional disorders related to diabetic pathological conditions. Simulated results show that the impaired connectivity of the network could result in poor robustness in maintaining blood flow and perfused surface; under high fluid permeability conditions of capillary walls, the pressure gradient was much larger around the capillary bed, and this alteration led to a saturation level of the interstitial pressure when lymphatic flow drainage can't work effectively; the variations in network connectivity and permeability of capillary wall also had unfavorable influence on oxygen distributions in interstitial tissue. In addition, when the oxygen releasing capacity of hemoglobin was confined by glycosylated hemoglobin (HbA1) in the case of diabetes, the plasma could not be complemented with adequate oxygen and thus the hypoxic tissue range will be extended. This study illustrates that when microcirculation disturbances, including the structure of capillary network, the wall osmosis property and the capacity of blood binding oxygen occur in DM2, some negative impacts are raised on microvascular hemodynamics and metabolism circumstance of interstitial tissue. Copyright © 2018 Elsevier Inc. All rights reserved.

Resolving the Impact of Biological Processes on Water Transport in Unsaturated Porous Media Through Nuclear Magnetic Resonance Micro-Imaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Seymour, Joseph D.

2005-06-01

The magnetic resonance microscopy (MRM) work at Montana State University has extended the imaging of a single biofilm in a 1 mm capillary reactor to correlate T2 magnetic relaxation maps displaying biofilm structure with the corresponding velocity patterns in three dimensions in a Staphylococcus epidermidis biofilm fouled square capillary. A square duct geometry is chosen to provide correlation with existing experiments and simulations, as research bioreactors tend to be of square or rectangular cross section for optical or microelectrode access. The spatially resolved velocity data provide details on the impact of biofilm induced advection on mass transport from the bulkmore » fluid to the biofilm and through the capillary bioreactor.« less

Capillary rise and swelling in cellulose sponges

NASA Astrophysics Data System (ADS)

Ha, Jonghyun; Kim, Jungchul; Kim, Ho-Young

2015-11-01

A cellulose sponge, which is a mundane example of a porous hydrophilic structure, can absorb and hold a significant amount of liquid. We present the results of experimental and theoretical investigation of the dynamics of the capillary imbibition of various aqueous solutions in the sponge that swells at the same time. We find that the rate of water rise against the resistance caused by gravitational and viscous effects deviates from Washburn's rule beyond a certain threshold height. We rationalize the novel power law of the rise height versus time by combining Darcy's law with hygroscopic swelling equation and also predict the threshold height. The scaling law constructed through this work agrees well with the experimental results, shedding light on the physics of capillary flow in deforming porous media.

Silicon ribbon growth by a capillary action shaping technique

NASA Technical Reports Server (NTRS)

Schwuttke, G. H.; Schwuttke, G. H.; Ciszek, T. F.; Kran, A.

1977-01-01

Substantial improvements in ribbon surface quality are achieved with a higher melt meniscus than that attainable with the film-fed (EFG) growth technique. A capillary action shaping method is described in which meniscus shaping for the desired ribbon geometry occurs at the vertex of a wettable die. As ribbon growth depletes the melt meniscus, capillary action supplies replacement material. Topics discussed cover experimental apparatus and growth procedures; die materials investigations, fabrication and evaluation; process development for 25 mm, 38 mm, 50 mm and 100 mm silicon ribbons; and long grain direct solidification of silicon. Methods for the structural and electrical characterization of cast silicon ribbons are assessed as well as silicon ribbon technology for the 1978 to 1986 period.

Condensation in Nanoporous Packed Beds.

PubMed

Ally, Javed; Molla, Shahnawaz; Mostowfi, Farshid

2016-05-10

In materials with tiny, nanometer-scale pores, liquid condensation is shifted from the bulk saturation pressure observed at larger scales. This effect is called capillary condensation and can block pores, which has major consequences in hydrocarbon production, as well as in fuel cells, catalysis, and powder adhesion. In this study, high pressure nanofluidic condensation studies are performed using propane and carbon dioxide in a colloidal crystal packed bed. Direct visualization allows the extent of condensation to be observed, as well as inference of the pore geometry from Bragg diffraction. We show experimentally that capillary condensation depends on pore geometry and wettability because these factors determine the shape of the menisci that coalesce when pore filling occurs, contrary to the typical assumption that all pore structures can be modeled as cylindrical and perfectly wetting. We also observe capillary condensation at higher pressures than has been done previously, which is important because many applications involving this phenomenon occur well above atmospheric pressure, and there is little, if any, experimental validation of capillary condensation at such pressures, particularly with direct visualization.

Suppressing Crack Formation in Particulate Systems by Utilizing Capillary Forces

PubMed Central

Schneider, Monica; Maurath, Johannes; Fischer, Steffen B.; Weiß, Moritz; Willenbacher, Norbert; Koos, Erin

2017-01-01

Cracks, formed during the drying of particulate films, can reduce the effectiveness or even render products useless. We present a novel, generic approach to suppress crack formation in thin films made from hard particle suspensions, which are otherwise highly susceptible to cracking, using the capillary force between particles present when a trace amount of an immiscible liquid is added to a suspension. This secondary liquid preserves the particle cohesion, modifying the structure and increasing the drying rate. Crack-free films can be produced at thicknesses much greater than the critical cracking thickness for a suspension without capillary interactions, and even persists after sintering. This capillary suspension strategy is applicable to a broad range of materials including suspensions of metals, semiconductive and ceramic oxides or glassy polymeric particles and can be easily implemented in many industrial processes since it is based on well-established unit operations. Promising fields of application include ceramic foils and printed electronic devices. PMID:28263554

Atomic Fine-Structure Diagnostic and Cooling Transitions for Far Infrared and Submillimeter Observations

NASA Astrophysics Data System (ADS)

Balance, Connor

Some of the strongest emission lines observed from a variety of astronomical sources originate from transitions between fine-structure levels in the ground term of neutral atoms and lowly-charged ions. These fine-structure levels are populated due to collisions with -, H+, H, He, and/or H2 depending on the temperature and ionization fraction of e the environment. As fine-structure excitation measurements are rare, modeling applications depend on theoretically determined rate coefficients. However, for many ions electron collision studies have not been performed for a decade or more, while over that time period the theoretical/computational methodology has significantly advanced. For heavy-particle collisions, very few systems have been studied. As a result, most models rely on estimates or on low-quality collisional data for fine-structure excitation. To significantly advance the state of fine-structure data for astrophysical models, we propose a collaborative effort in electron collisions, heavy-particle collisions, and quantum chemistry. Using the R-matrix method, fine-structure excitation due to electron collisions will be investigated for C, O, Ne^+, Ne^2+, Ar^+, Ar^2+, Fe, Fe^+, and Fe^2+. Fine-structure excitation due to heavy-particle collisions will be studied with a fully quantum molecular-orbital approach using potential energy surfaces computed with a multireference configuration-interaction method. The systems to be studied include: C/H^+, C/H2, O/H^+, O/H2, Ne^+/H, Ne^+/H2, Ne^2+/H, Ne^2+/H2, Fe/H^+, Fe^+/H, and Fe^2+/H. 2D rigid-rotor surfaces will be constructed for H2 collisions, internuclear distance dependent spin-orbit coupling will be computed in some cases, and all rate coefficients will be obtained for the temperature range 10-2000 K. The availability the proposed fine-structure excitation data will lead to deeper examination and understanding of the properties of many astrophysical environments, including young stellar objects, protoplanetary disks, planetary nebulae, photodissociation regions, active galactic nuclei, and x-ray dominated regions, hence elevating the scientific return from current (SOFIA, Spitzer, Herschel, HST) and upcoming (JWST) NASA IR/Submm astrophysics missions, as well as from ground-based telescopes.

Synchrotron x-ray imaging visualization study of capillary-induced flow and critical heat flux on surfaces with engineered micropillars

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yu, Dong In; Kwak, Ho Jae; Noh, Hyunwoo

Over the past several decades, phenomena related to critical heat flux (CHF) on structured surfaces have received a large amount of attention from the research community. The purpose of such research has been to enhance the safety and efficiency of a variety of thermal systems. A number of theories have been put forward to explain the key CHF enhancement mechanisms on structured surfaces. However, these theories have not been confirmed experimentally due to limitations in the available visualization techniques and the complexity of the phenomena. To overcome the limitations of the previous visualization techniques and elucidate the CHF enhancement mechanismmore » on the structured surfaces, we introduce synchrotron X-ray imaging with high spatial (~2 μm) and time (~20,000 Hz) resolutions. Lastly, this technique has enabled us to confirm that capillary-induced flow is the key CHF enhancement mechanism on structured surfaces.« less

Synchrotron x-ray imaging visualization study of capillary-induced flow and critical heat flux on surfaces with engineered micropillars

DOE PAGES

Yu, Dong In; Kwak, Ho Jae; Noh, Hyunwoo; ...

2018-02-23

Over the past several decades, phenomena related to critical heat flux (CHF) on structured surfaces have received a large amount of attention from the research community. The purpose of such research has been to enhance the safety and efficiency of a variety of thermal systems. A number of theories have been put forward to explain the key CHF enhancement mechanisms on structured surfaces. However, these theories have not been confirmed experimentally due to limitations in the available visualization techniques and the complexity of the phenomena. To overcome the limitations of the previous visualization techniques and elucidate the CHF enhancement mechanismmore » on the structured surfaces, we introduce synchrotron X-ray imaging with high spatial (~2 μm) and time (~20,000 Hz) resolutions. Lastly, this technique has enabled us to confirm that capillary-induced flow is the key CHF enhancement mechanism on structured surfaces.« less

Reduction of the capillary water absorption of foamed concrete by using the porous aggregate

NASA Astrophysics Data System (ADS)

Namsone, E.; Sahmenko, G.; Namsone, E.; Korjakins, A.

2017-10-01

The article reports on the research of reduction of the capillary water absorption of foamed concrete (FC) by using the porous aggregate such as the granules of expanded glass (EG) and the cenospheres (CS). The EG granular aggregate is produced by using recycled glass and blowing agents, melted down in high temperature. The unique structure of the EG granules is obtained where the air is kept closed inside the pellet. The use of the porous aggregate in the preparation process of the FC samples provides an opportunity to improve some physical and mechanical properties of the FC, classifying it as a product of high-performance. In this research the FC samples were produced by adding the EG granules and the CS. The capillary water absorption of hardened samples has been verified. The pore size distribution has been determined by microscope. It is a very important characteristic, specifically in the cold climate territories-where temperature often falls below zero degrees. It is necessary to prevent forming of the micro sized pores in the final structure of the material as it reduces its water absorption capacity. In addition, at a below zero temperature water inside these micro sized pores can increase them by expanding the stress on their walls during the freezing process. Research of the capillary water absorption kinetics can be practical for prevision of the FC durability.

Analysis and characterization of aluminum chlorohydrate oligocations by capillary electrophoresis.

PubMed

Ouadah, Nesrine; Moire, Claudine; Kuntz, Jean-François; Brothier, Fabien; Cottet, Hervé

2017-04-07

Aluminum chlorohydrates (ACH) are the active ingredients used in most antiperspirant products. ACH is a water soluble aluminum complex which contains several oligomeric polycations of aluminum with degrees of polymerization up to Al 13 or Al 30 . The characterization and quantification of ACH oligo-cations remain a challenging issue of primary interest for developing structure/antiperspirant activity correlations, and for controlling the ACH ingredients. In this work, highly repeatable capillary electrophoresis (CE) separation of A l3 + , Al 13 and Al 30 oligomers contained in ACH samples was obtained at pH 4.8, owing to a careful choice of the background electrolyte counter-ion and chromophore, capillary I.D. and capillary coating. This is the first reported separation of Al 13 and Al 30 oligomers in conditions that are compatible with the aluminum speciation in ACH solution or in conditions of antiperspirant application/formulation. Al 13 and Al 30 effective charge numbers were also determined from the sensitivity of detection in indirect UV detection mode. The relative mass proportion of Al 13 compared to Al 13 +Al 30 could be determined in different aluminum chlorohydrate samples. Due to its simplicity, repeatability/reproducibility, minimal sample preparation and mild analytical conditions, CE appears to be a promising analytical separation technique for the characterization of ACH materials and for the study of structure/antiperspirant activity correlations. Copyright © 2017. Published by Elsevier B.V.

Analysis of Proteins, Protein Complexes, and Organellar Proteomes Using Sheathless Capillary Zone Electrophoresis - Native Mass Spectrometry

NASA Astrophysics Data System (ADS)

Belov, Arseniy M.; Viner, Rosa; Santos, Marcia R.; Horn, David M.; Bern, Marshall; Karger, Barry L.; Ivanov, Alexander R.

2017-12-01

Native mass spectrometry (MS) is a rapidly advancing field in the analysis of proteins, protein complexes, and macromolecular species of various types. The majority of native MS experiments reported to-date has been conducted using direct infusion of purified analytes into a mass spectrometer. In this study, capillary zone electrophoresis (CZE) was coupled online to Orbitrap mass spectrometers using a commercial sheathless interface to enable high-performance separation, identification, and structural characterization of limited amounts of purified proteins and protein complexes, the latter with preserved non-covalent associations under native conditions. The performance of both bare-fused silica and polyacrylamide-coated capillaries was assessed using mixtures of protein standards known to form non-covalent protein-protein and protein-ligand complexes. High-efficiency separation of native complexes is demonstrated using both capillary types, while the polyacrylamide neutral-coated capillary showed better reproducibility and higher efficiency for more complex samples. The platform was then evaluated for the determination of monoclonal antibody aggregation and for analysis of proteomes of limited complexity using a ribosomal isolate from E. coli. Native CZE-MS, using accurate single stage and tandem-MS measurements, enabled identification of proteoforms and non-covalent complexes at femtomole levels. This study demonstrates that native CZE-MS can serve as an orthogonal and complementary technique to conventional native MS methodologies with the advantages of low sample consumption, minimal sample processing and losses, and high throughput and sensitivity. This study presents a novel platform for analysis of ribosomes and other macromolecular complexes and organelles, with the potential for discovery of novel structural features defining cellular phenotypes (e.g., specialized ribosomes). [Figure not available: see fulltext.

Determination of the fine structure constant using helium fine structure.

PubMed

Smiciklas, Marc; Shiner, David

2010-09-17

We measure 31,908,131.25(30) kHz for the 2(3)}P J=0 to 2 fine structure interval in helium. The difference between this and theory to order mα7 (20 Hz numerical uncertainty) implies 0.22(30) kHz for uncalculated terms. The measurement is performed by using atomic beam and electro-optic laser techniques. Various checks include a 3He 2{3}S hyperfine measurement. We can obtain an independent value for the fine structure constant α with a 5 ppb experimental uncertainty. However, dominant mα8 terms (potentially 1.2 kHz) limit the overall uncertainty to a less competitive 20 ppb in α.

g-Factor of heavy ions: a new access to the fine structure constant.

PubMed

Shabaev, V M; Glazov, D A; Oreshkina, N S; Volotka, A V; Plunien, G; Kluge, H-J; Quint, W

2006-06-30

A possibility for a determination of the fine structure constant in experiments on the bound-electron g-factor is examined. It is found that studying a specific difference of the g-factors of B- and H-like ions of the same spinless isotope in the Pb region to the currently accessible experimental accuracy of 7 x 10(-10) would lead to a determination of the fine structure constant to an accuracy which is better than that of the currently accepted value. Further improvements of the experimental and theoretical accuracy could provide a value of the fine structure constant which is several times more precise than the currently accepted one.

XAFS SPECTROSCOPY ANALYSIS OF SELECTED HAP ELEMENTS IN FINE PM DERIVED FROM COAL COMBUSTION

EPA Science Inventory

X-ray absorption fine structure (XAFS) spectroscopy has been used to investigate the valence states and molecular structures of sulfur (S), chromium (Cr), arsenic (As), and zinc (Zn) in fine particulate matter (PM) separated from coal flyash produced in a realistic combustion sys...

Surface capillary currents: Rediscovery of fluid-structure interaction by forced evolving boundary theory

NASA Astrophysics Data System (ADS)

Wang, Chunbai; Mitra, Ambar K.

2016-01-01

Any boundary surface evolving in viscous fluid is driven with surface capillary currents. By step function defined for the fluid-structure interface, surface currents are found near a flat wall in a logarithmic form. The general flat-plate boundary layer is demonstrated through the interface kinematics. The dynamics analysis elucidates the relationship of the surface currents with the adhering region as well as the no-slip boundary condition. The wall skin friction coefficient, displacement thickness, and the logarithmic velocity-defect law of the smooth flat-plate boundary-layer flow are derived with the advent of the forced evolving boundary method. This fundamental theory has wide applications in applied science and engineering.

Ultrafast exciton fine structure relaxation dynamics in lead chalcogenide nanocrystals.

PubMed

Johnson, Justin C; Gerth, Kathrine A; Song, Qing; Murphy, James E; Nozik, Arthur J; Scholes, Gregory D

2008-05-01

The rates of fine structure relaxation in PbS, PbSe, and PbTe nanocrystals were measured on a femtosecond time scale as a function of temperature with no applied magnetic field by cross-polarized transient grating spectroscopy (CPTG) and circularly polarized pump-probe spectroscopy. The relaxation rates among exciton fine structure states follow trends with nanocrystal composition and size that are consistent with the expected influence of material dependent spin-orbit coupling, confinement enhanced electron-hole exchange interaction, and splitting between L valleys that are degenerate in the bulk. The size dependence of the fine structure relaxation rate is considerably different from what is observed for small CdSe nanocrystals, which appears to result from the unique material properties of the highly confined lead chalcogenide quantum dots. Modeling and qualitative considerations lead to conclusions about the fine structure of the lowest exciton absorption band, which has a potentially significant bearing on photophysical processes that make these materials attractive for practical purposes.

Polygamy and an absence of fine-scale structure in Dendroctonus ponderosae (Hopk.) (Coleoptera: Curcilionidae) confirmed using molecular markers

PubMed Central

Janes, J K; Roe, A D; Rice, A V; Gorrell, J C; Coltman, D W; Langor, D W; Sperling, F A H

2016-01-01

An understanding of mating systems and fine-scale spatial genetic structure is required to effectively manage forest pest species such as Dendroctonus ponderosae (mountain pine beetle). Here we used genome-wide single-nucleotide polymorphisms to assess the fine-scale genetic structure and mating system of D. ponderosae collected from a single stand in Alberta, Canada. Fine-scale spatial genetic structure was absent within the stand and the majority of genetic variation was best explained at the individual level. Relatedness estimates support previous reports of pre-emergence mating. Parentage assignment tests indicate that a polygamous mating system better explains the relationships among individuals within a gallery than the previously reported female monogamous/male polygynous system. Furthermore, there is some evidence to suggest that females may exploit the galleries of other females, at least under epidemic conditions. Our results suggest that current management models are likely to be effective across large geographic areas based on the absence of fine-scale genetic structure. PMID:26286666

CO2 Capillary-Trapping Processes in Deep Saline Aquifers

NASA Astrophysics Data System (ADS)

Gershenzon, Naum I.; Soltanian, Mohamadreza; Ritzi, Robert W., Jr.; Dominic, David F.

2014-05-01

The idea of reducing the Earth's greenhouse effect by sequestration of CO2 into the Earth's crust has been discussed and evaluated for more than two decades. Deep saline aquifers are the primary candidate formations for realization of this idea. Evaluation of reservoir capacity and the risk of CO2 leakage require a detailed modeling of the migration and distribution of CO2 in the subsurface structure. There is a finite risk that structural (or hydrodynamic) trapping by caprock may be compromised (e.g. by improperly abandoned wells, stratigraphic discontinuities, faults, etc.). Therefore, other trapping mechanisms (capillary trapping, dissolution, and mineralization) must be considered. Capillary trapping may be very important in providing a "secondary-seal", and is the focus of our investigation. The physical mechanism of CO2 trapping in porous media by capillary trapping incorporates three related processes, i.e. residual trapping, trapping due to hysteresis of the relative permeability, and trapping due to hysteresis of the capillary pressure. Additionally CO2 may be trapped in heterogeneous media due to difference in capillary pressure entry points for different materials. The amount of CO2 trapped by these processes is a complicated nonlinear function of the spatial distribution of permeability, permeability anisotropy, capillary pressure, relative permeability of brine and CO2, permeability hysteresis and residual gas saturation (as well as the rate, total amount and placement of injected CO2). Geological heterogeneities essentially affect the dynamics of a CO2 plume in subsurface environments. Recent studies have led to new conceptual and quantitative models for sedimentary architecture in fluvial deposits over a range of scales that are relevant to the performance of some deep saline reservoirs [1, 2]. We investigated how the dynamics of a CO2 plume, during and after injection, is influenced by the hierarchical and multi-scale stratal architecture in such reservoirs. The results strongly suggest that representing these small scales features, and representing how they are organized within a hierarchy of larger-scale features, is critical to understanding capillary trapping processes. References [1] Bridge, J.S. (2006), Fluvial facies models: Recent developments, in Facies Models Revisited, SEPM Spec. Publ., 84, edited by H. W. Posamentier and R. G. Walker, pp. 85-170, Soc. for Sediment. Geol. (SEPM), Tulsa, Okla [2] Ramanathan, R., A. Guin, R.W. Ritzi, D.F. Dominic, V.L. Freedman, T.D. Scheibe, and I.A. Lunt (2010), Simulating the heterogeneity in channel belt deposits: Part 1. A geometric-based methodology and code, Water Resources Research, v. 46, W04515.

Connecting traces of galaxy evolution: the missing core mass-morphological fine structure relation

NASA Astrophysics Data System (ADS)

Bonfini, P.; Bitsakis, T.; Zezas, A.; Duc, P.-A.; Iodice, E.; González-Martín, O.; Bruzual, G.; González Sanoja, A. J.

2018-01-01

Deep exposure imaging of early-type galaxies (ETGs) are revealing the second-order complexity of these objects, which have been long considered uniform, dispersion-supported spheroidals. `Fine structure' features (e.g. ripples, plumes, tidal tails, rings) as well as depleted stellar cores (i.e. central light deficits) characterize a number of massive ETG galaxies, and can be interpreted as the result of galaxy-galaxy interactions. We discuss how the time-scale for the evolution of cores and fine structures are comparable, and hence it is expected that they develop in parallel after the major interaction event which shaped the ETG. Using archival data, we compare the `depleted stellar mass' (i.e. the mass missing from the depleted stellar core) against the prominence of the fine structure features, and observe that they correlate inversely. This result confirms our expectation that, while the supermassive black hole (SMBH) binary (constituted by the SMBHs of the merger progenitors) excavates the core via three-body interactions, the gravitational potential of the newborn galaxy relaxes, and the fine structures fade below detection levels. We expect the inverse correlation to hold at least within the first Gyr from the merger which created the SMBH binary; after then, the fine structure evolves independently.

Bubble Point Measurements with Liquid Methane of a Screen Channel Capillary Liquid Acquisition Device

NASA Technical Reports Server (NTRS)

Jurns, John M.; McQuillen, John B.; Gaby, Joseph D., Jr.; Sinacore, Steven A., Jr.

2009-01-01

Liquid acquisition devices (LADs) can be utilized within a propellant tank in space to deliver single-phase liquid to the engine in low gravity. One type of liquid acquisition device is a screened gallery whereby a fine mesh screen acts as a 'bubble filter' and prevents the gas bubbles from passing through until a crucial pressure differential condition across the screen, called the bubble point, is reached. This paper presents data for LAD bubble point data in liquid methane (LCH4) for stainless steel Dutch twill screens with mesh sizes of 325 by 2300. These tests represent the first known nonproprietary effort to collect bubble point data for LCH4.

Nanoclusters of α-Fe naturally formed in twinned martensite after martensitic transformation

NASA Astrophysics Data System (ADS)

Liu, X.; Ping, D. H.; Xiang, H. P.; Lu, X.; Shen, J.

2018-05-01

Various Fe-C binary alloys with the carbon content from 0.05 to 2.0 (wt. %) have been prepared and water-quenched at austenitizing temperatures. The fine structure of the twinned martensite in the quenched samples has been investigated by means of transmission electron microscopy (TEM) in order to understand the initial products during the formation of the martensite structure. In the twinned structure (body-centered-cubic {112}⟨111⟩-type twin), TEM dark field observations have revealed that both matrix and twinned crystal regions are fully composed of ultra-fine particles (α-Fe nano-crystallites). The particles tend to have the same preferred direction (or texture) in the twinned martensite and the size is almost the same (1-2 nm). The ultra-fine particle structure has been commonly observed regardless of the carbon content; however, such a fine particle structure has been observed only in the martensite with the twinning structure. After in-situ TEM heating, recrystallization occurred and the fine particles merged into larger α-Fe grains; at the same time, the twinned relationship also disappeared.

Parallel generation of uniform fine droplets at hundreds of kilohertz in a flow-focusing module.

PubMed

Bardin, David; Kendall, Michael R; Dayton, Paul A; Lee, Abraham P

2013-01-01

Droplet-based microfluidic systems enable a variety of biomedical applications from point-of-care diagnostics with third world implications, to targeted therapeutics alongside medical ultrasound, to molecular screening and genetic testing. Though these systems maintain the key advantage of precise control of the size and composition of the droplet as compared to conventional methods of production, the low rates at which droplets are produced limits translation beyond the laboratory setting. As well, previous attempts to scale up shear-based microfluidic systems focused on increasing the volumetric throughput and formed large droplets, negating many practical applications of emulsions such as site-specific therapeutics. We present the operation of a parallel module with eight flow-focusing orifices in the dripping regime of droplet formation for the generation of uniform fine droplets at rates in the hundreds of kilohertz. Elevating the capillary number to access dripping, generation of monodisperse droplets of liquid perfluoropentane in the parallel module exceeded 3.69 × 10(5) droplets per second, or 1.33 × 10(9) droplets per hour, at a mean diameter of 9.8 μm. Our microfluidic method offers a novel means to amass uniform fine droplets in practical amounts, for instance, to satisfy clinical needs, with the potential for modification to form massive amounts of more complex droplets.

Interfacial layering and capillary roughness in immiscible liquids.

PubMed

Geysermans, P; Pontikis, V

2010-08-21

The capillary roughness and the atomic density profiles of extended interfaces between immiscible liquids are determined as a function of the interface area by using molecular dynamics and Lennard-Jones (12-6) potentials. We found that with increasing area, the interface roughness diverges logarithmically, thus fitting the theoretical mean-field prediction. In systems small enough for the interfacial roughness not to blur the structural details, atomic density profiles across the fluid interface are layered with correlation length in the range of molecular correlations in liquids. On increasing the system size, the amplitude of the thermally excited position fluctuations of the interface increases, thus causing layering to rapidly vanish, if density profiles are computed without special care. In this work, we present and validate a simple method, operating in the direct space, for extracting from molecular dynamics trajectories the "intrinsic" structure of a fluid interface that is the local density profile of the interface cleaned from capillary wave effects. Estimated values of interfacial properties such as the tension, the intrinsic width, and the lower wavelength limit of position fluctuations are in agreement with results collected from the literature.

Separation of thiol and cyanide hydrolysis products of chemical warfare agents by capillary electrophoresis.

PubMed

Copper, Christine L; Collins, Greg E

2004-03-01

The fluorescence derivatizing agent, o-phthalaldehyde (OPA), has been applied to the separation and detection of cyanide and several structurally similar thiols by capillary electrophoresis (CE)-laser induced fluorescence (LIF). Of particular interest to this investigation was the separation of 2-dimethylaminoethanethiol, 2-diethylaminoethanethiol, and cyanide, each of which are hydrolysis products or hydrolysis product simulants of the chemical warfare (CW) agents O-ethyl S-2-diisopropylaminoethyl methylphosphonothiolate (VX), O-isobutyl S-2-diethylaminoethyl methylphosphonothiolate (R-VX), and tabun (GA). Other structurally similar thiols simultaneously resolved by this method include 1-pentanethiol and 2-mercaptoethanol. Instrumental parameters were probed and optimum values for capillary length (50 cm) and inner diameter (75 microm), injection time (30 s) and field strength (15 kV) were determined. Sample stacking methods enabled detection limits of 9.3 microg/L for cyanide, 1.8 microg/L for 2-diethylaminoethanethiol, 35 microg/L for 2-dimethylaminoethanethiol, 15 microg/L for 2-mercaptoethanol, and 89 microg/L for 1-pentanethiol. The linearity of the method was verified over an order of magnitude and the reproducibility was found to be 3.0%.

Single-step CE for miniaturized and easy-to-use system.

PubMed

Ono, Koichi; Kaneda, Shohei; Fujii, Teruo

2013-03-01

We developed a novel single-step capillary electrophoresis (SSCE) scheme for miniaturized and easy to use system by using a microchannel chip, which was made from the hydrophilic material polymethyl methacrylate (PMMA), equipped with a capillary stop valve. Taking the surface tension property of liquids into consideration, the capillary effect was used to introduce liquids and control capillary stop valves in a partial barrier structure in the wall of the microchannel. Through the combined action of stop valves and air vents, both sample plug formation for electrophoresis and sample injection into a separation channel were successfully performed in a single step. To optimize SSCE, different stop valve structures were evaluated using actual microchannel chips and the finite element method with the level set method. A partial barrier structure at the bottom of the channel functioned efficiently as a stop valve. The stability of stop valve was confirmed by a shock test, which was performed by dropping the microchannel chip to a floor. Sample plug deformation could be reduced by minimizing the size of the side partial barrier. By dissolving hydroxyl ethyl cellulose and using it as the sample solution, the EOF and adsorption of the sample into the PMMA microchannel were successfully reduced. Using this method, a 100-bp DNA ladder was concentrated; good separation was observed within 1 min. At a separation length of 5 mm, the signal was approximately 20-fold higher than a signal of original sample solution by field-amplified sample stacking effect. All operations, including liquid introduction and sample separation, can be completed within 2 min by using the SSCE scheme. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

An Action-Based Fine-Grained Access Control Mechanism for Structured Documents and Its Application

PubMed Central

Su, Mang; Li, Fenghua; Tang, Zhi; Yu, Yinyan; Zhou, Bo

2014-01-01

This paper presents an action-based fine-grained access control mechanism for structured documents. Firstly, we define a describing model for structured documents and analyze the application scenarios. The describing model could support the permission management on chapters, pages, sections, words, and pictures of structured documents. Secondly, based on the action-based access control (ABAC) model, we propose a fine-grained control protocol for structured documents by introducing temporal state and environmental state. The protocol covering different stages from document creation, to permission specification and usage control are given by using the Z-notation. Finally, we give the implementation of our mechanism and make the comparisons between the existing methods and our mechanism. The result shows that our mechanism could provide the better solution of fine-grained access control for structured documents in complicated networks. Moreover, it is more flexible and practical. PMID:25136651

An action-based fine-grained access control mechanism for structured documents and its application.

PubMed

Su, Mang; Li, Fenghua; Tang, Zhi; Yu, Yinyan; Zhou, Bo

2014-01-01

This paper presents an action-based fine-grained access control mechanism for structured documents. Firstly, we define a describing model for structured documents and analyze the application scenarios. The describing model could support the permission management on chapters, pages, sections, words, and pictures of structured documents. Secondly, based on the action-based access control (ABAC) model, we propose a fine-grained control protocol for structured documents by introducing temporal state and environmental state. The protocol covering different stages from document creation, to permission specification and usage control are given by using the Z-notation. Finally, we give the implementation of our mechanism and make the comparisons between the existing methods and our mechanism. The result shows that our mechanism could provide the better solution of fine-grained access control for structured documents in complicated networks. Moreover, it is more flexible and practical.

A biological approach to assembling tissue modules through endothelial capillary network formation.

PubMed

Riesberg, Jeremiah J; Shen, Wei

2015-09-01

To create functional tissues having complex structures, bottom-up approaches to assembling small tissue modules into larger constructs have been emerging. Most of these approaches are based on chemical reactions or physical interactions at the interface between tissue modules. Here we report a biological assembly approach to integrate small tissue modules through endothelial capillary network formation. When adjacent tissue modules contain appropriate extracellular matrix materials and cell types that support robust endothelial capillary network formation, capillary tubules form and grow across the interface, resulting in assembly of the modules into a single, larger construct. It was shown that capillary networks formed in modules of dense fibrin gels seeded with human umbilical vein endothelial cells (HUVECs) and mesenchymal stem cells (MSCs); adjacent modules were firmly assembled into an integrated construct having a strain to failure of 117 ± 26%, a tensile strength of 2208 ± 83 Pa and a Young's modulus of 2548 ± 574 Pa. Under the same culture conditions, capillary networks were absent in modules of dense fibrin gels seeded with either HUVECs or MSCs alone; adjacent modules disconnected even when handled gently. This biological assembly approach eliminates the need for chemical reactions or physical interactions and their associated limitations. In addition, the integrated constructs are prevascularized, and therefore this bottom-up assembly approach may also help address the issue of vascularization, another key challenge in tissue engineering. Copyright © 2015 John Wiley & Sons, Ltd.

Improvement of chromatographic performances of in-situ synthesized hybrid C8 silica monoliths by reduction of structural radial heterogeneities.

PubMed

Roux, R; Abi Jaoudé, M; Demesmay, C

2009-05-01

Several modifications of a previously described protocol are proposed to improve the performances of in-situ synthesized C(8) hybrid silica monoliths. Our attention was focused on reducing the sources of radial heterogeneity that may be responsible for the poor efficiencies observed in the hydrodynamic elution mode. It was demonstrated that a decrease in the temperature of the capillary during the filling step equally to that of the polymerization mixture (0 degrees C), associated with a decrease of the gelation temperature to 20 degrees C along with a new pre-treatment of the capillary's internal walls [with a mixture of tetraethoxysilane (TEOS)/EtOH (1/3, v/v)] allows (i) increasing the radial homogeneity of the monolith, thus further enhancing the performances in the nano-liquid chromatography (nano-LC) mode, (ii) improving the capillary to capillary reproducibility in terms of permeability and efficiencies. In fact, the average minimum plate height H(min) was lowered from 24 to 14 microm and the capillary-to-capillary reproducibility of the synthesis was widely improved by factors two and three of reduction on the calculated standard deviation, respectively for both the efficiency in the nano-LC mode and the permeability. At last, the improved radial homogeneity and anchoring of the synthesized monoliths allowed increasing the inner diameter of the capillary (up to 150 microm) without any significant loss in efficiency. Finally, long term stability of the as-obtained monolithic stationary phases in terms of retention and efficiency was studied. In addition, the evaluation of their chromatographic behaviour was also achieved with the Tanaka test and the results were compared to those already published for commercial monoliths (Chromolith) as well as for particulate stationary phases.

Ultra-high-stability, pH-resistant sol-gel titania poly(tetrahydrofuran) coating for capillary microextraction on-line coupled to high-performance liquid chromatography.

PubMed

Segro, Scott S; Cabezas, Yaniel; Malik, Abdul

2009-05-15

A sol-gel titania poly(tetrahydrofuran) (poly-THF) coating was developed for capillary microextraction hyphenated on-line with high-performance liquid chromatography (HPLC). Poly-THF was covalently bonded to the sol-gel titania network which, in turn, became chemically anchored to the inner surface of a 0.25mm I.D. fused silica capillary. For sample preconcentration, a 38-cm segment of the sol-gel titania poly-THF coated capillary was installed on an HPLC injection port as a sampling loop. Aqueous samples containing a variety of analytes were passed through the capillary and, during this process, the analytes were extracted by the sol-gel titania poly-THF coating on the inner surface of the capillary. Using isocratic and gradient elution with acetonitrile/water mobile phases, the extracted analytes were desorbed into the on-line coupled HPLC column for separation and UV detection. The sol-gel titania poly-THF coating was especially efficient in extracting polar analytes, such as underivatized phenols, alcohols, amines, and aromatic carboxylic acids. In addition, this coating was capable of extracting moderately polar and nonpolar analytes, such as ketones and polycyclic aromatic hydrocarbons. The sol-gel titania poly-THF coated capillary was also able to extract polypeptides at pH values near their respective isoelectric points. Extraction of these compounds can be important for environmental and biomedical applications. The observed extraction behavior can be attributed to the polar and nonpolar moieties in the poly-THF structure. This coating was found to be stable under extremely low and high pH conditions-even after 18h of exposure to 1M HCl (pH approximately 0.0) and 1M NaOH (pH approximately 14.0).

Identification of capillary rarefaction using intracoronary wave intensity analysis with resultant prognostic implications for cardiac allograft patients.

PubMed

Broyd, Christopher J; Hernández-Pérez, Francisco; Segovia, Javier; Echavarría-Pinto, Mauro; Quirós-Carretero, Alicia; Salas, Clara; Gonzalo, Nieves; Jiménez-Quevedo, Pilar; Nombela-Franco, Luis; Salinas, Pablo; Núñez-Gil, Ivan; Del Trigo, Maria; Goicolea, Javier; Alonso-Pulpón, Luis; Fernández-Ortiz, Antonio; Parker, Kim; Hughes, Alun; Mayet, Jamil; Davies, Justin; Escaned, Javier

2018-05-21

Techniques for identifying specific microcirculatory structural changes are desirable. As such, capillary rarefaction constitutes one of the earliest changes of cardiac allograft vasculopathy (CAV) in cardiac allograft recipients, but its identification with coronary flow reserve (CFR) or intracoronary resistance measurements is hampered because of non-selective interrogation of the capillary bed. We therefore investigated the potential of wave intensity analysis (WIA) to assess capillary rarefaction and thereby predict CAV. Fifty-two allograft patients with unobstructed coronary arteries and normal left ventricular (LV) function were assessed. Adequate aortic pressure and left anterior descending artery flow measurements at rest and with intracoronary adenosine were obtained in 46 of which 2 were lost to follow-up. In a subgroup of 15 patients, simultaneous RV biopsies were obtained and analysed for capillary density. Patients were followed up with 1-3 yearly screening angiography. A significant relationship with capillary density was noted with CFR (r = 0.52, P = 0.048) and the backward decompression wave (BDW) (r = -0.65, P < 0.01). Over a mean follow-up of 9.3 ± 5.2 years patients with a smaller BDW had an increased risk of developing angiographic CAV (hazard ratio 2.89, 95% CI 1.12-7.39; P = 0.03). Additionally, the index BDW was lower in those who went on to have a clinical CAV-events (P = 0.04) as well as more severe disease (P = 0.01). Within cardiac transplant patients, WIA is able to quantify the earliest histological changes of CAV and can predict clinical and angiographic outcomes. This proof-of-concept for WIA also lends weight to its use in the assessment of other disease processes in which capillary rarefaction is involved.

InAs Band-Edge Exciton Fine Structure

DTIC Science & Technology

2015-07-29

Chapter 1 InAs Band-Edge Exciton Fine Structure 1.1 Contributions This work was carried out in collaboration with Oscar Sandoval, a summer student at...diffusion,1,2 charg- ing,2,3 and excitonic fine structure.1,3–9 While spectral diffusion and charging are most likely photoinduced effects and thus can be...unavoidable. A complete understanding of the excitonic 1 Distribution A: Public Release energy landscape enables us to determine dephasing rates

Atomic sulfur: Frequency measurement of the J = 0 left arrow 1 fine-structure transition at 56.3 microns by laser magnetic resonance

NASA Technical Reports Server (NTRS)

Brown, John M.; Evenson, Kenneth M.; Zink, Lyndon R.

1994-01-01

The J = 0 left arrow 1 fine-structure transition in atomic sulfur (S I) in its ground (3)P state has been detected in the laboratory by far-infrared laser magnetic resonance. The fine-structure interval has been measured accurately as 5,322,492.9 +/- 2.8 MHz which corresponds to a wavelength of 56.325572 +/- 0.000030 micrometers.

Wettability Control on Fluid-Fluid Displacements in Patterned Microfluidics

NASA Astrophysics Data System (ADS)

Zhao, B.; Trojer, M.; Cueto-Felgueroso, L.; Juanes, R.

2014-12-01

Two-phase flow in porous media is important in many natural and industrial processes like geologic CO2 sequestration, enhanced oil recovery, and water infiltration in soil. While it is well known that the wetting properties of porous media can vary drastically depending on the type of media and the pore fluids, the effect of wettability on fluid displacement continues to challenge our microscopic and macroscopic descriptions. Here we study this problem experimentally, starting with the classic experiment of two-phase flow in a capillary tube. We image the shape of the meniscus and measure the associated capillary pressure for a wide range of capillary numbers. We confirm that wettability exerts a fundamental control on meniscus deformation, and synthesize new observations on the dependence of the dynamic capillary pressure on wetting properties (contact angle) and flow conditions (viscosity contrast and capillary number). We compare our experiments to a macroscopic phase-field model of two-phase flow. We use the insights gained from the capillary tube experiments to explore the viscous fingering instability in the Hele-Shaw geometry in the partial-wetting regime. A key difference between a Hele-Shaw cell and a porous medium is the existence of micro-structures (i.e. pores and pore throats). To investigate how these micro-structrues impact fluid-fluid displacement, we conduct experiments on a planar microfluidic device patterned with vertical posts. We track the evolution of the fluid-fluid interface and elucidate the impact of wetting on the cooperative nature of fluid displacement during pore invasion events. We use the insights gained from the capillary tube and patterned microfluidics experiments to elucidate the effect of wetting properties on viscous fingering and capillary fingering in a Hele-Shaw cell filled with glass beads, where we observe a contact-angle-dependent stabilizing behavior for the emerging flow instabilities, as the system transitions from drainage to imbibition.

Critical Velocities in Open Capillary Flow

NASA Technical Reports Server (NTRS)

Dreyer, Michael; Langbein, Dieter; Rath, Hans J.

1996-01-01

This paper describes the proposed research program on open capillary flow and the preliminary work performed theoretically and in drop tower experiments. The work focuses on the fundamental physical understanding of the flow through capillary bound geometries, where the circumference of the cross section of the flow path contains free surfaces. Examples for such a flow configuration are capillary vanes in surface tension tanks, flow along edges and corners and flow through liquid bridges. The geometries may be classified by their cross section areas, wetted circumferences and the radii of curvature of the free surfaces. In the streaming float zone the flow path is bound by a free surface only. The ribbon vane is a model for vane types used in surface tension tanks, where a structure in proximity to the tank wall forms a capillary gap. A groove is used in heat pipes for the transportation of the condensed working fluid to the heat source and a wedge may occur in a spaceborne experiment where fluid has to be transported by the means of surface tension. The research objectives are the determination of the maximum volume flux, the observation of the free surfaces and the liquid flow inside the flow path as well as the evaluation of the limiting capillary wave speed. The restriction of the maximum volume flux is due to convective forces (flow velocity exceeding the capillary wave speed) and/or viscous forces, i.e. the viscous head loss along the flow path must be compensated by the capillary pressure due to the curved free surface. Exceeding the maximum volume flux leads to the choking of the flow path, thus the free surface collapses and.gas ingestion occurs at the outlet. The means are ground-based experimental work with plateau tanks and in a drop tower, a sounding rocket flight, and theoretical analysis with integral balances as well as full three dimensional CFD solutions for flow with free surfaces.

Investigation of the capillary flow through open surface microfluidic structures

NASA Astrophysics Data System (ADS)

Taher, Ahmed; Jones, Benjamin; Fiorini, Paolo; Lagae, Liesbet

2017-02-01

The passive nature of capillary microfluidics for pumping and actuation of fluids is attractive for many applications including point of care medical diagnostics. For such applications, there is often the need to spot dried chemical reagents in the bottom of microfluidic channels after device fabrication; it is often more practical to have open surface devices (i.e., without a cover or lid). However, the dynamics of capillary driven flow in open surface devices have not been well studied for many geometries of interest. In this paper, we investigate capillary flow in an open surface microchannel with a backward facing step. An analytical model is developed to calculate the capillary pressure as the liquid-vapor interface traverses a backward facing step in an open microchannel. The developed model is validated against results from Surface Evolver liquid-vapor surface simulations and ANSYS Fluent two-phase flow simulations using the volume of fluid approach. Three different aspect ratios (inlet channel height by channel width) were studied. The analytical model shows good agreement with the simulation results from both modeling methods for all geometries. The analytical model is used to derive an expression for the critical aspect ratio (the minimum channel aspect ratio for flow to proceed across the backward facing step) as a function of contact angle.

Interfacing Capillary-Based Separations to Mass Spectrometry Using Desorption Electrospray Ionization

PubMed Central

Barbula, Griffin K.; Safi, Samir; Chingin, Konstantin; Perry, Richard H.; Zare, Richard N.

2014-01-01

The powerful hybrid analysis method of capillary-based separations followed by mass spectrometric analysis gives substantial chemical identity and structural information. It is usually carried out using electrospray ionization. However, the salts and detergents used in the mobile phase for electrokinetic separations suppress ionization efficiencies and contaminate the inlet of the mass spectrometer. This report describes a new method that uses desorption electrospray ionization (DESI) to overcome these limitations. Effluent from capillary columns is deposited on a rotating Teflon disk that is covered with paper. As the surface rotates, the temporal separation of the eluting analytes (i.e., the electropherogram) is spatially encoded on the surface. Then, using DESI, surface-deposited analytes are preferentially ionized, reducing the effects of ion suppression and inlet contamination on signal. With the use of this novel approach, two capillary-based separations were performed: a mixture of the rhodamine dyes at milligram/milliliter levels in a 10 mM sodium borate solution was separated by capillary electrophoresis, and a mixture of three cardiac drugs at milligram/milliliter levels in a 12.5 mM sodium borate and 12.5 mM sodium dodecyl sulfate solution was separated by micellar electrokinetic chromatography. In both experiments, the negative effects of detergents and salts on the MS analyses were minimized. PMID:21319740

The CE-Way of Thinking: "All Is Relative!".

PubMed

Schmitt-Kopplin, Philippe; Fekete, Agnes

2016-01-01

Over the last two decades the development of capillary electrophoresis instruments lead to systems with programmable sampler, separation column, separation buffer, and detection devices comparable visually in many aspects to the setup of classical chromatography.Two processes make capillary electrophoresis essentially different from chromatography and are the basis of the CE-way of thinking, namely, the injection type and the liquid flow within the capillary. (1) When the injection is made hydrodynamically (such as in most of the found applications in the literature), the injected volumes are directly dependent on the type and size of the separation capillary. (2) The buffer velocity is not pressure driven as in liquid chromatography but electrokinetically governed by the quality of the capillary surface (separation buffer dependant surface charge) inducing an electroosmotic flow (EOF). The EOF undergoes small variations and is not necessarily identical from one separation or day to the other. The direct consequence is an apparent nonreproducible migration time of the analytes, even though the own velocity of the ions is the same.The effective mobility (field strength normalized velocity) of the ions is a possible parameterization from acquired timescale to effective mobility-scale electropherograms leading to a reproducible visualization and better quantification with a direct relation to structural characters of the analytes (i.e., charge and size-see chapter on semiempirical modelization).

Determination of the saturated film conductivity to improve the EMFX model in describing the soil hydraulic properties over the entire moisture range

NASA Astrophysics Data System (ADS)

Wang, Yunquan; Ma, Jinzhu; Guan, Huade; Zhu, Gaofeng

2017-06-01

Difficulty in measuring hydraulic conductivity, particularly under dry conditions, calls for methods of predicting the conductivity from easily obtained soil properties. As a complement to the recently published EMFX model, a method based on two specific suction conditions is proposed to estimate saturated film conductivity from the soil water retention curve. This method reduces one fitting parameter in the previous EMFX model, making it possible to predict the hydraulic conductivity from the soil water retention curve over the complete moisture range. Model performance is evaluated with published data of soils in a broad texture range from sand to clay. The testing results indicate that 1) the modified EMFX model (namely the EMFX-K model), incorporating both capillary and adsorption forces, provides good agreement with the conductivity data over the entire moisture range; 2) a value of 0.5 for the tortuosity factor in the EMFX-K model as that in the Mualem's model gives comparable estimation of the relative conductivity associated with the capillary force; and 3) a value of -1.0 × 10-20 J for the Hamaker constant, rather than the commonly used value of -6.0 × 10-20 J, appears to be more appropriate to represent solely the effect of the van der Waals forces and to predict the film conductivity. In comparison with the commonly used van Genuchten-Mualem model, the EMFX-K model significantly improves the prediction of hydraulic conductivity under dry conditions. The sensitivity analysis result suggests that the uncertainty in the film thickness estimation is important in explaining the model underestimation of hydraulic conductivity for the soils with fine texture, in addition to the uncertainties from the measurements and the model structure. High quality data that cover the complete moisture range for a variety of soil textures are required to further test the method.

Mixing in wicking structures and the use of enhanced mixing within wicks in microchannel devices

DOEpatents

Stenkamp, Victoria S [Richland, WA; TeGrotenhuis, Ward E [Kennewick, WA; Wegeng, Robert S [Alexandria, VA

2009-06-02

Advanced wicking structures and methods utilizing these structures are described. The use of advanced wicking structures can promote rapid mass transfer while maintaining high capillary pressure through the use of small pores. Particularly improved results in fluid contacting processes can be achieved by enhanced mixing within a wicking layer within a microchannel.

Mixing in wicking structures and the use of enhanced mixing within wicks in microchannel devices

DOEpatents

Stenkamp, Victoria S [Richland, WA; TeGrotenhuis, Ward E [Kennewick, WA; Wegeng, Robert S [Richland, WA

2011-04-19

Advanced wicking structures and methods utilizing these structures are described. The use of advanced wicking structures can promote rapid mass transfer while maintaining high capillary pressure through the use of small pores. Particularly improved results in fluid contacting processes can be achieved by enhanced mixing within a wicking layer within a microchannel.

Differential-Integral method in polymer processing: Taking melt electrospinning technique for example

NASA Astrophysics Data System (ADS)

Haoyi, Li; Weimin, Yang; Hongbo, Chen; Jing, Tan; Pengcheng, Xie

2016-03-01

A concept of Differential-Integral (DI) method applied in polymer processing and molding was proposed, which included melt DI injection molding, DI nano-composites extrusion molding and melt differential electrospinning principle and equipment. Taking the melt differential electrospinning for example to introduce the innovation research progress, two methods preparing polymer ultrafine fiber have been developed: solution electro-spinning and melt electro-spinning, between which solution electro-spinning is much simpler to realize in lab. More than 100 institutions have endeavored to conduct research on it and more than 30 thousand papers have been published. However, its industrialization was restricted to some extend because of the existence of toxic solvent during spinning process and poor mechanical strength of resultant fibers caused by small pores on fiber surface. Solvent-free melt electrospinning is environmentally friendly and highly productive. However, problems such as the high melt viscosity, thick fiber diameter and complex equipment makes it relatively under researched compared with solution electrospinning. With the purpose of solving the shortage of traditional electro-spinning equipment with needles or capillaries, a melt differential electro-spinning method without needles or capillaries was firstly proposed. Nearly 50 related patents have been applied since 2005, and systematic method innovations and experimental studies have also been conducted. The prepared fiber by this method had exhibited small diameter and smooth surface. The average fiber diameter can reach 200-800 nm, and the single nozzle can yield two orders of magnitude more than the capillaries. Based on the above principle, complete commercial techniques and equipment have been developed to produce ultra-fine non-woven fabrics for the applications in air filtration, oil spill recovery and water treatment, etc.

Fine reservoir structure modeling based upon 3D visualized stratigraphic correlation between horizontal wells: methodology and its application

NASA Astrophysics Data System (ADS)

Chenghua, Ou; Chaochun, Li; Siyuan, Huang; Sheng, James J.; Yuan, Xu

2017-12-01

As the platform-based horizontal well production mode has been widely applied in petroleum industry, building a reliable fine reservoir structure model by using horizontal well stratigraphic correlation has become very important. Horizontal wells usually extend between the upper and bottom boundaries of the target formation, with limited penetration points. Using these limited penetration points to conduct well deviation correction means the formation depth information obtained is not accurate, which makes it hard to build a fine structure model. In order to solve this problem, a method of fine reservoir structure modeling, based on 3D visualized stratigraphic correlation among horizontal wells, is proposed. This method can increase the accuracy when estimating the depth of the penetration points, and can also effectively predict the top and bottom interfaces in the horizontal penetrating section. Moreover, this method will greatly increase not only the number of points of depth data available, but also the accuracy of these data, which achieves the goal of building a reliable fine reservoir structure model by using the stratigraphic correlation among horizontal wells. Using this method, four 3D fine structure layer models have been successfully built of a specimen shale gas field with platform-based horizontal well production mode. The shale gas field is located to the east of Sichuan Basin, China; the successful application of the method has proven its feasibility and reliability.

Fine-structure-resolution for Rovibrational Excitation of CN Due to H2

NASA Astrophysics Data System (ADS)

Byrd, Nat; Yang, Benhui H.; Stancil, Phillip C.

2018-06-01

Diatomic molecules can be readily excited in interstellar environments exposed to intense UV radiation, such as the inner rim of a protoplanetary disk. Non-thermal populations of excited rovibrational levels can result, for example, following decay from electronically excited states to the electronic ground state. Competition between radiative decay and collisional processes, mostly due to H2, determine the resulting rovibrational emission spectrum. For CN, and other open-shell molecules, the resulting spectrum will be complicated due to fine-structure splitting of the rotational levels. In some cases, fine-structure resolution has been previously computed for rotational transitions in atom- or diatom-diatom collisional processes. Here we present the first fine-structure resolution for vibrational deexcitation for CN colliding with H2. The collisional cross sections were computed using a 6D potential energy surface with a full close-coupling approach. Fine-structure resolution is obtained by adopting an angular momentum recoupling scheme to transform the scattering matrices to a recoupled basis. Here we present low-energy calculations for the v=1 to 0 transition.This work was supported by NASA Grant NNX16AF09G.

The impact of cochlear fine structure on hearing thresholds and DPOAE levels

NASA Astrophysics Data System (ADS)

Lee, Jungmee; Long, Glenis; Talmadge, Carrick L.

2004-05-01

Although otoacoustic emissions (OAE) are used as clinical and research tools, the correlation between OAE behavioral estimates of hearing status is not large. In normal-hearing individuals, the level of OAEs can vary as much as 30 dB when the frequency is changed less than 5%. These pseudoperiodic variations of OAE level with frequency are known as fine structure. Hearing thresholds measured with high-frequency resolution reveals a similar (up to 15 dB) fine structure. We examine the impact of OAE and threshold fine structures on the prediction of auditory thresholds from OAE levels. Distortion product otoacoustic emissions (DPOAEs) were measured with sweeping primary tones. Psychoacoustic detection thresholds were measured using pure tones, sweep tones, FM tones, and narrow-band noise. Sweep DPOAE and narrow-band threshold estimates provide estimates that are less influenced by cochlear fine structure and should lead to a higher correlation between OAE levels and psychoacoustic thresholds. [Research supported by PSC CUNY, NIDCD, National Institute on Disability and Rehabilitation Research in U.S. Department of Education, and The Ministry of Education in Korea.

Ultrafast preparation of a polyhedral oligomeric silsesquioxane-based ionic liquid hybrid monolith via photoinitiated polymerization, and its application to capillary electrochromatography of aromatic compounds.

PubMed

Zhang, Bingyu; Lei, Xiaoyun; Deng, Lijun; Li, Minsheng; Yao, Sicong; Wu, Xiaoping

2018-06-06

An ionic liquid hybrid monolithic capillary column was prepared within 7 min via photoinitiated free-radical polymerization of an ionic liquid monomer (1-butyl-3-vinylimidazolium-bis[(trifluoromethyl)sulfonyl]imide); VBIMNTF 2 ) and a methacryl substituted polyhedral oligomeric silsesquioxane (POSS-MA) acting as a cross-linker. The effects of composition of prepolymerization solution and initiation time on the porous structure and electroosmotic flow (EOF) of monolithic column were investigated. The hybrid monolith was characterized by scanning electron microscopy and FTIR. Owing to the introduction of a rigid nanosized POSS silica core and ionic liquids with multiple interaction sites, the monolithic column has a well-defined 3D skeleton morphology, good mechanical stability, and a stable anodic electroosmotic flow. The hybrid monolithic stationary phase was applied to the capillary electrochromatographic separation of various alkylbenzenes, phenols, anilines and polycyclic aromatic hydrocarbons (PAHs). The column efficiency is highest (98,000 plates/m) in case of alkylbenzenes. Mixed-mode retention mechanisms including hydrophobic interactions, π-π stacking, electrostatic interaction and electrophoretic mobility can be observed. This indicates the potential of this material in terms of efficient separation of analytes of different structural type. Graphical Abstract Preparation of a mixed-mode ionic liquid hybrid monolithic column via photoinitiated polymerization of methacryl substituted polyhedral oligomeric silsesquioxane (POSS-MA) and 1-butyl-3-vinylimidazolium-bis[(trifluoromethyl)sulfonyl]imide (VBIMNTF 2 ) ionic liquid for use in capillary electrochromatography.

Experimental investigations on sodium-filled heat pipes

NASA Technical Reports Server (NTRS)

Dorner, S.; Reiss, F.; Schretzmann, K.

1977-01-01

The possibilities of producing heat pipes and, especially, the necessary capillary structures are discussed. Several types of heat pipes were made from stainless steel and tested at temperatures between 400 and 1055 deg C. The thermal power was determined by a calorimeter. Results indicate: bubble-free evaporation of sodium from rectangular open chennels is possible with a heat flux of more than 1,940 W/sq cm at 1055 C. The temperature drop along the tube could be measured only at low temperatures. A subdivided heat pipe worked against the gravitational field. A heat pipe with a capillary structure made of a rolled screen was supported by rings and bars operated at 250 W/sq cm heat flux in the evaporating region.

CONSTRAINTS ON SPATIAL VARIATIONS IN THE FINE-STRUCTURE CONSTANT FROM PLANCK

DOE Office of Scientific and Technical Information (OSTI.GOV)

O'Bryan, Jon; Smidt, Joseph; De Bernardis, Francesco

2015-01-01

We use the cosmic microwave background (CMB) anisotropy data from Planck to constrain the spatial fluctuations of the fine-structure constant α at a redshift of 1100. We use a quadratic estimator to measure the four-point correlation function of the CMB temperature anisotropies and extract the angular power spectrum fine-structure constant spatial variations projected along the line of sight at the last scattering surface. At tens of degree angular scales and above, we constrain the fractional rms fluctuations of the fine-structure constant to be (δα/α){sub rms} < 3.4 × 10{sup –3} at the 68% confidence level. We find no evidence formore » a spatially varying α at a redshift of 10{sup 3}.« less

Preparation of a thermoresponsive polymer grafted polystyrene monolithic capillary for the separation of bioactive compounds.

PubMed

Koriyama, Takuya; Asoh, Taka-Aki; Kikuchi, Akihiko

2016-11-01

To develop aqueous microseparation columns for bioactive compounds, a thermoresponsive polymer grafted polymer monolith was prepared inside silica capillaries having an I.D. of 100μm by polymerization of styrene (St) with m/p-divinylbenzene (DVB) in the presence of polydimethylsiloxane as porogen, followed by surface-initiated atom transfer radical polymerization (SI-ATRP) of N-isopropylacrylamide (NIPAAm). SEM analysis indicated that the resulting poly(N-isopropylacrylamide) (PNIPAAm) grafted polystyrene monolith had a consecutive three-dimensionally interconnected structure and through-pores, similar to the base polystyrene (PSt) monolith. The elution behavior of steroids with different hydrophobicity was evaluated using micro-high-performance liquid chromatography in sole aqueous mobile phase. Temperature dependent interaction changes were observed between steroids and the PNIPAAm modified surfaces. Furthermore, the interaction between bioactive compounds and the PNIPAAm grafted PSt surfaces was controlled and eventually separate these molecules with different hydrophobicities by simple temperature modulation in aqueous environment. The PNIPAAm grafted PSt monolithic capillary showed improved separation properties of bioactive compounds, compared with a PNIPAAm grafted hollow capillary in aqueous environment. Copyright © 2016 Elsevier B.V. All rights reserved.

Detection system of capillary array electrophoresis microchip based on optical fiber

NASA Astrophysics Data System (ADS)

Yang, Xiaobo; Bai, Haiming; Yan, Weiping

2009-11-01

To meet the demands of the post-genomic era study and the large parallel detections of epidemic diseases and drug screening, the high throughput micro-fluidic detection system is needed urgently. A scanning laser induced fluorescence detection system based on optical fiber has been established by using a green laser diode double-pumped solid-state laser as excitation source. It includes laser induced fluorescence detection subsystem, capillary array electrophoresis micro-chip, channel identification unit and fluorescent signal processing subsystem. V-shaped detecting probe composed with two optical fibers for transmitting the excitation light and detecting induced fluorescence were constructed. Parallel four-channel signal analysis of capillary electrophoresis was performed on this system by using Rhodamine B as the sample. The distinction of different samples and separation of samples were achieved with the constructed detection system. The lowest detected concentration is 1×10-5 mol/L for Rhodamine B. The results show that the detection system possesses some advantages, such as compact structure, better stability and higher sensitivity, which are beneficial to the development of microminiaturization and integration of capillary array electrophoresis chip.

Gas adsorption and capillary condensation in nanoporous alumina films.

PubMed

Casanova, Fèlix; Chiang, Casey E; Li, Chang-Peng; Roshchin, Igor V; Ruminski, Anne M; Sailor, Michael J; Schuller, Ivan K

2008-08-06

Gas adsorption and capillary condensation of organic vapors are studied by optical interferometry, using anodized nanoporous alumina films with controlled geometry (cylindrical pores with diameters in the range of 10-60 nm). The optical response of the film is optimized with respect to the geometric parameters of the pores, for potential performance as a gas sensor device. The average thickness of the adsorbed film at low relative pressures is not affected by the pore size. Capillary evaporation of the liquid from the nanopores occurs at the liquid-vapor equilibrium described by the classical Kelvin equation with a hemispherical meniscus. Due to the almost complete wetting, we can quantitatively describe the condensation for isopropanol using the Cohan model with a cylindrical meniscus in the Kelvin equation. This model describes the observed hysteresis and allows us to use the adsorption branch of the isotherm to calculate the pore size distribution of the sample in good agreement with independent structural measurements. The condensation for toluene lacks reproducibility due to incomplete surface wetting. This exemplifies the relevant role of the fluid-solid (van der Waals) interactions in the hysteretic behavior of capillary condensation.

Enrichment of Glycoproteins using Nano-scale Chelating Con A Monolithic Capillary Chromatography

PubMed Central

Feng, Shun; Yang, Na; Pennathur, Subramaniam; Goodison, Steve; Lubman, David M.

2009-01-01

Immobilized lectin chromatography can be employed for glycoprotein enrichment, but commonly used columns have limitations of yield and resolution. In order to improve efficiency and to make the technique applicable to minimal sample material, we have developed a nano-scale chelating Concanavalin A (Con A) monolithic capillary prepared using GMA-EDMA (glycidyl methacrylate–co-ethylene dimethacrylate) as polymeric support. Con A was immobilized on Cu(II)-charged iminodiacetic acid (IDA) regenerable sorbents by forming a IDA:Cu(II):Con A sandwich affinity structure that has high column capacity as well as stability. When compared with conventional Con A lectin chromatography, the monolithic capillary enabled the better reproducible detection of over double the number of unique N-glycoproteins in human urine samples. Utility for analysis of minimal biological samples was confirmed by the successful elucidation of glycoprotein profiles in mouse urine samples at the microliter scale. The improved efficiency of the nano-scale monolithic capillary will impact the analysis of glycoproteins in complex biological samples, especially where only limited material may be available. PMID:19366252

Steroids in porcine follicular fluid: analysis by HPLC, capillary CG and capillary CG/MS after purification on SEP-PAK C18 and ion exchange chromatography.

PubMed

Khalil, M W; Lawson, V

1983-04-01

Steroids in porcine follicular fluid have been concentrated by reverse phase chromatography in SEP-PAK C18 and purified further on the cation exchanger SP-Sephadex C-25. Fractionation into unconjugated neutral and phenolic steroids, glucuronides and sulfates was carried out on triethylaminohydroxypropyl Sephadex LH-20 (TEAP-LH-20). The unconjugated neutral fraction was analysed by high pressure liquid chromatography (HPLC) on a C18 radial cartridge 5 mm I.D.; 10 mu, or on a C18 5 mu RESOLVE column, and by capillary gas chromatography (GC) on a 12 M OV-1 cross linked fused silica column. Testosterone, progesterone and androstenedione were the major steroids detected by HPLC monitored at 254 nm, although 17- hydroxy-, 20 alpha-dihydro- and 20 beta-dihydroprogesterone were also present. Pregnenolone, pregnanediol, dehydroepiandrosterone, 17-hydroxypregnenolone and androsterone were detected by capillary CG as their 0-methyloxime trimethylsilyether derivatives. Further confirmation of structure was provided by complete mass spectral data or by selective ion monitoring (SIM).

Heparin/heparan sulfate analysis by covalently modified reverse polarity capillary zone electrophoresis-mass spectrometry.

PubMed

Sanderson, Patience; Stickney, Morgan; Leach, Franklin E; Xia, Qiangwei; Yu, Yanlei; Zhang, Fuming; Linhardt, Robert J; Amster, I Jonathan

2018-04-13

Reverse polarity capillary zone electrophoresis coupled to negative ion mode mass spectrometry (CZE-MS) is shown to be an effective and sensitive tool for the analysis of glycosaminoglycan mixtures. Covalent modification of the inner wall of the separation capillary with neutral or cationic reagents produces a stable and durable surface that provides reproducible separations. By combining CZE-MS with a cation-coated capillary and a sheath flow interface, a rapid and reliable method has been developed for the analysis of sulfated oligosaccharides from dp4 to dp12. Several different mixtures have been separated and detected by mass spectrometry. The mixtures were selected to test the capability of this approach to resolve subtle differences in structure, such as sulfation position and epimeric variation of the uronic acid. The system was applied to a complex mixture of heparin/heparan sulfate oligosaccharides varying in chain length from dp3 to dp12 and more than 80 molecular compositions were identified by accurate mass measurement. Copyright © 2018 Elsevier B.V. All rights reserved.

Dynamics and density distributions in a capillary-discharge waveguide with an embedded supersonic jet

DOE Office of Scientific and Technical Information (OSTI.GOV)

Matlis, N. H., E-mail: nmatlis@gmail.com; Gonsalves, A. J.; Steinke, S.

We present an analysis of the gas dynamics and density distributions within a capillary-discharge waveguide with an embedded supersonic jet. This device provides a target for a laser plasma accelerator which uses longitudinal structuring of the gas-density profile to enable control of electron trapping and acceleration. The functionality of the device depends sensitively on the details of the density profile, which are determined by the interaction between the pulsed gas in the jet and the continuously-flowing gas in the capillary. These dynamics are captured by spatially resolving recombination light from several emission lines of the plasma as a function ofmore » the delay between the jet and the discharge. We provide a phenomenological description of the gas dynamics as well as a quantitative evaluation of the density evolution. In particular, we show that the pressure difference between the jet and the capillary defines three regimes of operation with qualitatively different longitudinal density profiles and show that jet timing provides a sensitive method for tuning between these regimes.« less

Spectral structure and stability studies on microstructure-fiber continuum

NASA Astrophysics Data System (ADS)

Gu, Xun; Kimmel, Mark; Zeek, Erik; Shreenath, Aparna P.; Trebino, Rick P.; Windeler, Robert S.

2003-07-01

Although previous direct measurements of the microstructure-fiber continuum have all showed a smooth and stable spectrum, our cross-correlation frequency-resolved optical gating (XFROG) full-intensity-and-phase characterization of the continuum pulse, utilizing sum-frequency-generation with a pre-characterized reference pulse and the angle-dithered-crystal technique, indicates that fine-scale spectral structure exists on a single-shot basis, contrary to previous observations. In particular, deep and fine oscillations are found in the retrieved spectrum, and the retrieved trace contains a "measles" pattern, whereas the measured trace and the independently-measured spectrum are rather smooth. The discrepancy is shown to be the result of unstable single-shot spectral structure. Although the XFROG measurement is not able to directly measure the single-shot fine structure in the trace, the redundancy of information in FROG traces enables the retrieval algorithm to correctly recognize the existence of the spectral fine structure, and restore the structure in the retrieved trace and spectrum. Numerical simulations have supported our hypothesis, and we directly observed the fine spectral structure in single-shot measurements of the continuum spectrum and the structure was seen to be highly unstable, the continuum spectrum appearing smooth only when many shots are averaged. Despite the structure and instability in the continuum spectrum, coherence experiments also reveal that the spectral phase is rather stable, being able to produce well-defined spectral fringes across the entire continuum bandwidth.

Fine structural dependence of ultraviolet reflections in the King Penguin beak horn.

PubMed

Dresp, Birgitta; Langley, Keith

2006-03-01

The visual perception of many birds extends into the near-ultraviolet (UV) spectrum and ultraviolet is used by some to communicate. The beak horn of the King Penguin (Aptenodytes patagonicus) intensely reflects in the ultraviolet and this appears to be implicated in partner choice. In a preliminary study, we recently demonstrated that this ultraviolet reflectance has a structural basis, resulting from crystal-like photonic structures, capable of reflecting in the near-UV. The present study attempted to define the origin of the photonic elements that produce the UV reflectance and to better understand how the UV signal is optimized by their fine structure. Using light and electron microscopic analysis combined with new spectrophotometric data, we describe here in detail the fine structure of the entire King Penguin beak horn in addition to that of its photonic crystals. The data obtained reveal a one-dimensional structural periodicity within this tissue and demonstrate a direct relationship between its fine structure and its function. In addition, they suggest how the photonic structures are produced and how they are stabilized. The measured lattice dimensions of the photonic crystals, together with morphological data on its composition, permit predictions of the wavelength of reflected light. These correlate well with experimentally observed values. The way the UV signal is optimized by the fine structure of the beak tissue is discussed with regard to its putative biological role.

Apparent and microscopic dynamic contact angles in confined flows

NASA Astrophysics Data System (ADS)

Omori, Takeshi; Kajishima, Takeo

2017-11-01

An abundance of empirical correlations between a dynamic contact angle and a capillary number representing a translational velocity of a contact line have been provided for the last decades. The experimentally obtained dynamic contact angles are inevitably apparent contact angles but often undistinguished from microscopic contact angles formed right on the wall. As Bonn et al. ["Wetting and spreading," Rev. Mod. Phys. 81, 739-805 (2009)] pointed out, however, most of the experimental studies simply report values of angles recorded at some length scale which is quantitatively unknown. It is therefore hard to evaluate or judge the physical validity and the generality of the empirical correlations. The present study is an attempt to clear this clutter regarding the dynamic contact angle by measuring both the apparent and the microscopic dynamic contact angles from the identical data sets in a well-controlled manner, by means of numerical simulation. The numerical method was constructed so that it reproduced the fine details of the flow with a moving contact line predicted by molecular dynamics simulations [T. Qian, X. Wang, and P. Sheng, "Molecular hydrodynamics of the moving contact line in two-phase immiscible flows," Commun. Comput. Phys. 1, 1-52 (2006)]. We show that the microscopic contact angle as a function of the capillary number has the same form as Blake's molecular-kinetic model [T. Blake and J. Haynes, "Kinetics of liquid/liquid displacement," J. Colloid Interface Sci. 30, 421-423 (1969)], regardless of the way the flow is driven, the channel width, the mechanical properties of the receding fluid, and the value of the equilibrium contact angle under the conditions where the Reynolds and capillary numbers are small. We have also found that the apparent contact angle obtained by the arc-fitting of the interface behaves surprisingly universally as claimed in experimental studies in the literature [e.g., X. Li et al., "An experimental study on dynamic pore wettability," Chem. Eng. Sci. 104, 988-997 (2013)], although the angle deviates significantly from the microscopic contact angle. It leads to a practically important point that it suffices to measure arc-fitted contact angles to make formulae to predict flow rates in capillary tubes.

78 FR 43216 - Government-Owned Inventions; Availability for Licensing

Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-19

... tissue for grafting. Potential Commercial Applications: Tissue engineering. Simulation of physiological... oxygen diffusivity silicone hydrogel support structures that mimic tissue vasculature (e.g., capillary...

Spin fine structure of optically excited quantum dot molecules

NASA Astrophysics Data System (ADS)

Scheibner, M.; Doty, M. F.; Ponomarev, I. V.; Bracker, A. S.; Stinaff, E. A.; Korenev, V. L.; Reinecke, T. L.; Gammon, D.

2007-06-01

The interaction between spins in coupled quantum dots is revealed in distinct fine structure patterns in the measured optical spectra of InAs/GaAs double quantum dot molecules containing zero, one, or two excess holes. The fine structure is explained well in terms of a uniquely molecular interplay of spin-exchange interactions, Pauli exclusion, and orbital tunneling. This knowledge is critical for converting quantum dot molecule tunneling into a means of optically coupling not just orbitals but also spins.

Algebraic dynamic multilevel method for compositional flow in heterogeneous porous media

NASA Astrophysics Data System (ADS)

Cusini, Matteo; Fryer, Barnaby; van Kruijsdijk, Cor; Hajibeygi, Hadi

2018-02-01

This paper presents the algebraic dynamic multilevel method (ADM) for compositional flow in three dimensional heterogeneous porous media in presence of capillary and gravitational effects. As a significant advancement compared to the ADM for immiscible flows (Cusini et al., 2016) [33], here, mass conservation equations are solved along with k-value based thermodynamic equilibrium equations using a fully-implicit (FIM) coupling strategy. Two different fine-scale compositional formulations are considered: (1) the natural variables and (2) the overall-compositions formulation. At each Newton's iteration the fine-scale FIM Jacobian system is mapped to a dynamically defined (in space and time) multilevel nested grid. The appropriate grid resolution is chosen based on the contrast of user-defined fluid properties and on the presence of specific features (e.g., well source terms). Consistent mapping between different resolutions is performed by the means of sequences of restriction and prolongation operators. While finite-volume restriction operators are employed to ensure mass conservation at all resolutions, various prolongation operators are considered. In particular, different interpolation strategies can be used for the different primary variables, and multiscale basis functions are chosen as pressure interpolators so that fine scale heterogeneities are accurately accounted for across different resolutions. Several numerical experiments are conducted to analyse the accuracy, efficiency and robustness of the method for both 2D and 3D domains. Results show that ADM provides accurate solutions by employing only a fraction of the number of grid-cells employed in fine-scale simulations. As such, it presents a promising approach for large-scale simulations of multiphase flow in heterogeneous reservoirs with complex non-linear fluid physics.

Capillary electrochromatography and preconcentration of neutral compounds on poly(dimethylsiloxane) microchips.

PubMed

Ro, Kyung Won; Chang, Woo-Jin; Kim, Ho; Koo, Yoon-Mo; Hahn, Jong Hoon

2003-09-01

Capillary electrochromatography (CEC) and preconcentration of neutral compounds have been realized on poly(dimethylsiloxane) (PDMS) microchips. The channels are coated with polyelectrolyte multilayers to avoid absorption of hydrophobic analytes into PDMS. The structures of a microchip include an injector and a bead chamber with integrated frits, where the particles of the stationary phase are completely retained. Dimensions of the frit structures are 25 micro mx20 micro m, and the space between the structures is 3 micro m. A neutral compound, BODIPY, that is strongly absorbed into native PDMS, is successfully and selectively retained on octadecylsilane-coated silica beads in the bead chamber with a concentration enhancement of up to 100 times and eluted with elution buffer solution containing 70% acetonitrile. Preconcentrations and CEC separations of coumarins have been conducted with the same device and achieved complete separations in less than 50 s.

Co-Culture of Human Endothelial Cells and Foreskin Fibroblasts on 3D Silk-Fibrin Scaffolds Supports Vascularization.

PubMed

Samal, Juhi; Weinandy, Stefan; Weinandy, Agnieszka; Helmedag, Marius; Rongen, Lisanne; Hermanns-Sachweh, Benita; Kundu, Subhas C; Jockenhoevel, Stefan

2015-10-01

A successful strategy to enhance the in vivo survival of engineered tissues would be to prevascularize them. In this study, fabricated silk fibroin scaffolds from mulberry and non-mulberry silkworms are investigated and compared for supporting the co-culture of human umbilical vein endothelial cells and human foreskin fibroblasts. Scaffolds are cytocompatible and when combined with fibrin gel support capillary-like structure formation. Density and interconnectivity of the formed structures are found to be better in mulberry scaffolds. ELISA shows that levels of vascular endothelial growth factor (VEGF) released in co-cultures with fibrin gel are significantly higher than in co-cultures without fibrin gel. RT PCR shows an increase in VEGFR2 expression in mulberry scaffolds indicating these scaffolds combined with fibrin provide a suitable microenvironment for the development of capillary-like structures. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Separation of saccharides derivatized with 2-aminobenzoic acid by capillary electrophoresis and their structural consideration by nuclear magnetic resonance.

PubMed

He, Liping; Sato, Kae; Abo, Mitsuru; Okubo, Akira; Yamazaki, Sunao

2003-03-01

Saccharides including mono- and disaccharides were quantitatively derivatized with 2-aminobenzoic acid (2-AA). These derivatives were then separated by capillary zone electrophoresis with UV detection using 50mM sodium phosphate buffer as the running electrolyte solution. In particular, the saccharide derivatives with the same molecular weight as 2-AA aldohexoses (mannose and glucose) and 2-AA aldopentoses (ribose and xylose) were well separated. The underlying reasons for separation were explored by studying their structural data using 1H and 13C NMR. It was found that the configurational difference between their hydroxyl group at C2 or C3 could cause the difference in Stokes' radii between their molecules and thus lead to different electrophoretic mobilities. The correlation between the electrophoretic behavior of these carbohydrate derivatives and their structures was studied utilizing the calculated molecular models of the 2-AA-labeled mannose, glucose, ribose, and xylose.

Development of a high-performance boiling heat exchanger by improved liquid supply to narrow channels.

PubMed

Ohta, Haruhiko; Ohno, Toshiyuki; Hioki, Fumiaki; Shinmoto, Yasuhisa

2004-11-01

A two-phase flow loop is a promising method for application to thermal management systems for large-scale space platforms handling large amounts of energy. Boiling heat transfer reduces the size and weight of cold plates. The transportation of latent heat reduces the mass flow rate of working fluid and pump power. To develop compact heat exchangers for the removal of waste heat from electronic devices with high heat generation density, experiments on a method to increase the critical heat flux for a narrow heated channel between parallel heated and unheated plates were conducted. Fine grooves are machined on the heating surface in a transverse direction to the flow and liquid is supplied underneath flattened bubbles by the capillary pressure difference from auxiliary liquid channels separated by porous metal plates from the main heated channel. The critical heat flux values for the present heated channel structure are more than twice those for a flat surface at gap sizes 2 mm and 0.7 mm. The validity of the present structure with auxiliary liquid channels is confirmed by experiments in which the liquid supply to the grooves is interrupted. The increment in the critical heat flux compared to those for a flat surface takes a maximum value at a certain flow rate of liquid supply to the heated channel. The increment is expected to become larger when the length of the heated channel is increased and/or the gravity level is reduced.

Characterization of heterogeneity in the Heletz sandstone from core to pore scale and quantification of its impact on multi-phase flow

DOE PAGES

Hingerl, Ferdinand F.; Yang, Feifei; Pini, Ronny; ...

2016-02-02

In this paper we present the results of an extensive multiscale characterization of the flow properties and structural and capillary heterogeneities of the Heletz sandstone. We performed petrographic, porosity and capillary pressure measurements on several subsamples. We quantified mm-scale heterogeneity in saturation distributions in a rock core during multi-phase flow using conventional X-ray CT scanning. Core-flooding experiments were conducted under reservoirs conditions (9 MPa, 50 °C) to obtain primary drainage and secondary imbibition relative permeabilities and residual trapping was analyzed and quantified. We provide parameters for relative permeability, capillary pressure and trapping models for further modeling studies. A synchrotron-based microtomographymore » study complements our cm- to mm-scale investigation by providing links between the micromorphology and mm-scale saturation heterogeneities.« less

Root exudate as major player on soil-water retention dynamics

NASA Astrophysics Data System (ADS)

Albalasmeh, A. A.; Sweet, J. R.; Gebrenegus, T. B.; Ghezzehei, T. A.

2012-12-01

Plant roots and soil microbes release 5-60% of the entirety of photosynthetically fixed carbon in to the soil as exudates to adapt to their surrounding. There is indirect evidence suggesting that these exudates play a major role in altering the of the soil water retention properties. In this study, we used a uniformly sized (40 μm) glass beads and various concentrations (0, 2, 10, 20 and 29 g/L) of polygalacutronic acid (PGA) to mimic sandy soil and the organic exudates from plant roots, respectively. The samples were subjected to periods of drying and subsequent equilibration. At each stage, the water potential was measured using WP4C Dewpoint PotentiaMeter. The effect of root exudates on soil water retention can be attributed t at least two factors. The most widely speculated effect is through enhanced of soil aggregation. This effect is primarily due to capillary adhesion in fine pores within aggregates and is consistent was visual observation of pronounced aggregation in many rhizosphere soils. The second factor is related to osmotic effect of the exudate solution. Our observations show that the capillary effect is mostly to higher water potential regime (> -1 bar suction). Whereas the osmotic effect dominates in <- 1 bar suction. These results will provide direct quantitative evidence of how rhizosphere organic matter helps plant-soil relations.

Transition from a beads-on-string to a spike structure in an electrified viscoelastic jet

NASA Astrophysics Data System (ADS)

Li, Fang; Yin, Xie-Yuan; Yin, Xie-Zhen

2017-02-01

A one-dimensional numerical simulation is performed to study the nonlinear behaviors of a perfectly conducting, slightly viscoelastic liquid jet under a large radial electric field. A singular spike structure different from a beads-on-string structure is detected. The electric field is found to be the key factor for the formation of spikes. The transition from a beads-on-string to a spike structure occurs at sufficiently large electric fields. Moreover, the transition occurs more easily for smaller wave numbers. Viscosity is found to suppress spikes while elasticity promotes them. The mechanism responsible for spike formation is further explored by examining the maximum radius of the jet in the beads-on-string case. The capillary and electrostatic forces prove to be dominant in droplets, and the transition takes place when the electrostatic force exceeds the capillary force. The self-similarity in spikes is discussed. Different from the transition moment, the inertial, electrostatic, and solvent viscous forces are important in a developed spike.

Assessment of Perfused Foveal Microvascular Density and Identification of Nonperfused Capillaries in Healthy and Vasculopathic Eyes

PubMed Central

Pinhas, Alexander; Razeen, Moataz; Dubow, Michael; Gan, Alexander; Chui, Toco Y.; Shah, Nishit; Mehta, Mitul; Gentile, Ronald C.; Weitz, Rishard; Walsh, Joseph B.; Sulai, Yusufu N.; Carroll, Joseph; Dubra, Alfredo; Rosen, Richard B.

2014-01-01

Purpose. To analyze the foveal microvasculature of young healthy eyes and older vasculopathic eyes, imaged using in vivo adaptive optics scanning light ophthalmoscope fluorescein angiography (AOSLO FA). Methods. AOSLO FA imaging of the superficial retinal microvasculature within an 800-μm radius from the foveal center was performed using simultaneous confocal infrared (IR) reflectance (790 nm) and fluorescence (488 nm) channels. Corresponding IR structural and FA perfusion maps were compared with each other to identify nonperfused capillaries adjacent to the foveal avascular zone. Microvascular densities were calculated from skeletonized FA perfusion maps. Results. Sixteen healthy adults (26 eyes; mean age 25 years, range, 21–29) and six patients with a retinal vasculopathy (six eyes; mean age 55 years, range, 44–70) were imaged. At least one nonperfused capillary was observed in five of the 16 healthy nonfellow eyes and in four of the six vasculopathic eyes. Compared with healthy eyes, capillary nonperfusion in the vasculopathic eyes was more extensive. Microvascular density of the 16 healthy nonfellow eyes was 42.0 ± 4.2 mm−1 (range, 33–50 mm−1). All six vasculopathic eyes had decreased microvascular densities. Conclusions. AOSLO FA provides an in vivo method for estimating foveal microvascular density and reveals occult nonperfused retinal capillaries. Nonperfused capillaries in healthy young adults may represent a normal variation and/or an early sign of pathology. Although limited, the normative data presented here is a step toward developing clinically useful microvascular parameters for ocular and/or systemic diseases. PMID:25414179

Congenital amusia: a cognitive disorder limited to resolved harmonics and with no peripheral basis.

PubMed

Cousineau, Marion; Oxenham, Andrew J; Peretz, Isabelle

2015-01-01

Pitch plays a fundamental role in audition, from speech and music perception to auditory scene analysis. Congenital amusia is a neurogenetic disorder that appears to affect primarily pitch and melody perception. Pitch is normally conveyed by the spectro-temporal fine structure of low harmonics, but some pitch information is available in the temporal envelope produced by the interactions of higher harmonics. Using 10 amusic subjects and 10 matched controls, we tested the hypothesis that amusics suffer exclusively from impaired processing of spectro-temporal fine structure. We also tested whether the inability of amusics to process acoustic temporal fine structure extends beyond pitch by measuring sensitivity to interaural time differences, which also rely on temporal fine structure. Further tests were carried out on basic intensity and spectral resolution. As expected, pitch perception based on spectro-temporal fine structure was impaired in amusics; however, no significant deficits were observed in amusics' ability to perceive the pitch conveyed via temporal-envelope cues. Sensitivity to interaural time differences was also not significantly different between the amusic and control groups, ruling out deficits in the peripheral coding of temporal fine structure. Finally, no significant differences in intensity or spectral resolution were found between the amusic and control groups. The results demonstrate a pitch-specific deficit in fine spectro-temporal information processing in amusia that seems unrelated to temporal or spectral coding in the auditory periphery. These results are consistent with the view that there are distinct mechanisms dedicated to processing resolved and unresolved harmonics in the general population, the former being altered in congenital amusia while the latter is spared. Copyright © 2014 Elsevier Ltd. All rights reserved.

[Fine stereo structure for natural organic molecules, a preliminary study. II. Melting point influenced by structure factors].

PubMed

Lu, Y; Zheng, Q; Lu, D; Ma, P; Chen, Y

1995-06-01

Crystal structures of two compounds from Tripterygium wilfordii Hook f. have been determined by X-ray diffraction method. Structure factors influencing melting point of solid state have been analysed. Crystal class (or space group), recrystallization solvent, force between molecules and fine changes of molecular structures will all cause melting point changes of crystal substance.

Bubble Point Measurements with Liquid Methane of a Screen Capillary Liquid Acquisition Device

NASA Technical Reports Server (NTRS)

Jurns, John M.; McQuillen, John B.

2009-01-01

Liquid acquisition devices (LADs) can be utilized within a propellant tank in space to deliver single-phase liquid to the engine in low gravity. One type of liquid acquisition device is a screened gallery whereby a fine mesh screen acts as a bubble filter and prevents the gas bubbles from passing through until a crucial pressure differential condition across the screen, called the bubble point, is reached. This paper presents data for LAD bubble point data in liquid methane (LCH4) for stainless steel Dutch twill screens with mesh sizes of 325 by 2300 and 200 by 1400 wires per inch. Data is presented for both saturated and sub-cooled LCH4, and is compared with predicted values.

Application of ionic liquids in liquid chromatography and electrodriven separation.

PubMed

Huang, Yi; Yao, Shun; Song, Hang

2013-08-01

Ionic liquids (ILs) are salts in the liquid state at ambient temperature, which are nonvolatile, nonflammable with high thermal stability and dissolve easily for a wide range of inorganic and organic materials. As a kind of potential green solvent, they show high efficiency and selectivity in the field of separation research, especially in instrumental analysis. Thus far, ILs have been successfully applied by many related researchers in high-performance liquid chromatography and capillary electrophoresis as chromatographic stationary phases, mobile phase additives or electroosmotic flow modifiers. This paper provides a detailed review of these applications in the study of natural products, foods, drugs and other fine chemicals. Furthermore, the prospects of ILs in liquid chromatographic and electrodriven techniques are discussed.

Wet powder seal for gas containment

DOEpatents

Stang, Louis G.

1982-01-01

A gas seal is formed by a compact layer of an insoluble powder and liquid filling the fine interstices of that layer. The smaller the particle size of the selected powder, such as sand or talc, the finer will be the interstices or capillary spaces in the layer and the greater will be the resulting sealing capacity, i.e., the gas pressure differential which the wet powder layer can withstand. Such wet powder seal is useful in constructing underground gas reservoirs or storage cavities for nuclear wastes as well as stopping leaks in gas mains buried under ground or situated under water. The sealing capacity of the wet powder seal can be augmented by the hydrostatic head of a liquid body established over the seal.

Wet powder seal for gas containment

DOEpatents

Stang, L.G.

1979-08-29

A gas seal is formed by a compact layer of an insoluble powder and liquid filling the fine interstices of that layer. The smaller the particle size of the selected powder, such as sand or talc, the finer will be the interstices or capillary spaces in the layer and the greater will be the resulting sealing capacity, i.e., the gas pressure differential which the wet powder layer can withstand. Such wet powder seal is useful in constructing underground gas reservoirs or storage cavities for nuclear wastes as well as stopping leaks in gas mains buried under ground or situated under water. The sealing capacity of the wet powder seal can be augmented by the hydrostatic head of a liquid body established over the seal.

Laser marking on soda-lime glass by laser-induced backside wet etching with two-beam interference

NASA Astrophysics Data System (ADS)

Nakazumi, Tomoka; Sato, Tadatake; Narazaki, Aiko; Niino, Hiroyuki

2016-09-01

For crack-free marking of glass materials, a beam-scanning laser-induced backside wet etching (LIBWE) process by a beam spot with a fine periodic structure was examined. The fine periodic structure was produced within a beam spot by means of a Mach-Zehnder interferometer incorporated to the optical setup for the beam-scanning LIBWE. A fine structure with a period of 9 µm was observed within the microstructures with a diameter of ca. 40 µm fabricated by a laser shot under double-beam irradiation, and they could be homogeneously fabricated within an area of 800  ×  800 µm. The area filled with the microstructures, including fine periodic structures, could be observed in high contrast under a diffuse, on-axis illumination that was used in commercial QR code readers.

3D WHOLE-PROMINENCE FINE STRUCTURE MODELING

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gunár, Stanislav; Mackay, Duncan H.

2015-04-20

We present the first 3D whole-prominence fine structure model. The model combines a 3D magnetic field configuration of an entire prominence obtained from nonlinear force-free field simulations, with a detailed description of the prominence plasma. The plasma is located in magnetic dips in hydrostatic equilibrium and is distributed along multiple fine structures within the 3D magnetic model. Through the use of a novel radiative transfer visualization technique for the Hα line such plasma-loaded magnetic field model produces synthetic images of the modeled prominence comparable with high-resolution observations. This allows us for the first time to use a single technique tomore » consistently study, in both emission on the limb and absorption against the solar disk, the fine structures of prominences/filaments produced by a magnetic field model.« less

[Ultraviolet spectroscopic study on the fine structures in the solar polar hole].

PubMed

Zhang, Min; Wang, Dong; Liu, Guo-Hong

2014-07-01

Fine structures in the south solar polar coronal hole were observed by N IV line of SOHO/SUMER spectrograph. The scales of the fine structures range spatially range from 1 arcsec to several arcsecs, temporally from 1 min to several minutes, and parts of them are in strip shape along the slit direction. The line-of-sight velocity of them is up to tens of km x s(-1) with red and blue shift intercrossed occasionally, which appear periodically as long as 100 minutes in some regions. Part of the fine structures can be clearly observed at the Ne V III line with higher formation temperature in the same spectral window. The time and location of some fine structures with high velocity in the Ne V III spectrum are almost the same as that in N IV spectrum, but they are extended and diffused in the Ne V III spectrum. Some fine structures have non-Gaussian profiles with the line-of-sight Doppler velocities up to 150 km x s(-1) in the N IV blue/red wings, which is similar with the explosive events in the transition region. In the past, explosive events are small-scale dynamic phenomena often observed in the quiet-sun (QS) region, while their properties in coronal holes (CHs) remain unclear. Here, we find the EE-like events with strong dynamics in the south solar polar coronal hole by N IV line of SOHO/SUMER spectrograph.

Around Marshall

NASA Image and Video Library

1996-06-18

NASA scientist, in the Space Sciences lab at Marshall, works with capillary optics that generate more intense X-rays than conventional sources. This capability is useful in studying the structure of important proteins.

Anatomical evaluation of oral microcirculation: capillary characteristics associated with sex or age group.

PubMed

Scardina, Giuseppe Alessandro; Giuseppe Alessandro, Scardina; Cacioppo, Antonino; Antonino, Cacioppo; Messina, Pietro

2009-10-01

There are various types of oral mucosa specific to different parts of the mouth and each of these has a unique histological structure. The variations in the epithelial structure are consistently related to observable differences in the underlying microcirculation: i.e. differences in the course, conformation, and density of capillaries. The aim of this research has been to investigate oral microcirculatory differences between men and women as well as between various age groups, in order to map the oral mucosa, and to highlight changes occurring during aging. A total of 45 healthy subjects were enrolled for this study (12 men and 33 women; mean age 60.37; range 30-82). A complete in-vivo videocapillaroscopic mapping of the oral mucosa was done on each subject. The capillaroscopic patterns of the various areas differ particularly in the course of the loops in relation to the mucosal surface. On the basis of statistical analysis of the collected data, it emerges that there are many differences in capillary loop density between men and women and between different age groups. This study demonstrates the necessity of approaching the investigation of patient microcirculation in different ways depending on sex or age.

Cellular context–mediated Akt dynamics regulates MAP kinase signaling thresholds during angiogenesis

PubMed Central

Hellesøy, Monica; Lorens, James B.

2015-01-01

The formation of new blood vessels by sprouting angiogenesis is tightly regulated by contextual cues that affect angiogeneic growth factor signaling. Both constitutive activation and loss of Akt kinase activity in endothelial cells impair angiogenesis, suggesting that Akt dynamics mediates contextual microenvironmental regulation. We explored the temporal regulation of Akt in endothelial cells during formation of capillary-like networks induced by cell–cell contact with vascular smooth muscle cells (vSMCs) and vSMC-associated VEGF. Expression of constitutively active Akt1 strongly inhibited network formation, whereas hemiphosphorylated Akt1 epi-alleles with reduced kinase activity had an intermediate inhibitory effect. Conversely, inhibition of Akt signaling did not affect endothelial cell migration or morphogenesis in vSMC cocultures that generate capillary-like structures. We found that endothelial Akt activity is transiently blocked by proteasomal degradation in the presence of SMCs during the initial phase of capillary-like structure formation. Suppressed Akt activity corresponded to the increased endothelial MAP kinase signaling that was required for angiogenic endothelial morphogenesis. These results reveal a regulatory principle by which cellular context regulates Akt protein dynamics, which determines MAP kinase signaling thresholds necessary drive a morphogenetic program during angiogenesis. PMID:26023089

Variations in Grain-Scale Sediment Structure in a Gravel-Bed Channel as a Function of Fine Sediment Content and Morphological Location

NASA Astrophysics Data System (ADS)

Voepel, H.; Ahmed, S. I.; Hodge, R. A.; Leyland, J.; Sear, D. A.

2016-12-01

One of the major causes of uncertainty in estimates of bedload transport rates in gravel bed rivers is a lack of understanding of grain-scale sediment structure, and the impact that this structure has on bed stability. Furthermore, grain-scale structure varies throughout a channel and over time in ways that have not been fully quantified. Our research aims to quantify variations in sediment structure caused by two key variables; morphological location within a riffle-pool sequence (reflecting variation in hydraulic conditions), and the fine sediment content of the gravel bed (sand and clay). We report results from a series of flume experiments in which we water-worked a gravel bed with a riffle-pool morphology. The fine sediment content of the bed was incrementally increased over a series of runs from gravel only, to coarse sand, fine sand and two concentrations of clay. After each experimental run intact samples of the bed at different locations were extracted and the internal structure of the bed was measured using non-destructive, micro-focus X-ray computed tomography (CT) imaging. The CT images were processed to measure the properties of individual grains, including volume, center of mass, dimension, and contact points. From these data we were able to quantify the sediment structure through metrics including measurement of grain pivot angles, grain exposure and protrusion, and vertical variation in bed porosity and fine sediment content. Metrics derived from the CT data were verified using data from grain counts and tilt-table measurements on co-located samples. Comparison of the metrics across different morphological locations and fine sediment content demonstrates how these factors affect the bed structure. These results have implications for the development of sediment entrainment models for gravel bed rivers.

The high aerobic capacity of a small, marsupial rat-kangaroo (Bettongia penicillata) is matched by the mitochondrial and capillary morphology of its skeletal muscles.

PubMed

Webster, Koa N; Dawson, Terence J

2012-09-15

We examined the structure-function relationships that underlie the aerobic capacities of marsupial mammals that hop. Marsupials have relatively low basal metabolic rates (BMR) and historically were seen as 'low energy' mammals. However, the red kangaroo, Macropus rufus (family Macropodidae), has aerobic capacities equivalent to athletic placentals. It has an extreme aerobic scope (fAS) and its large locomotor muscles feature high mitochondrial and capillary volumes. M. rufus belongs to a modern group of kangaroos and its high fAS is not general for marsupials. However, other hopping marsupials may have elevated aerobic capacities. Bettongia penicillata, a rat-kangaroo (family Potoroidae), is a small (1 kg), active hopper whose fAS is somewhat elevated. We examined the oxygen delivery system in its muscles to ascertain links with hopping. An elevated fAS of 23 provided a relatively high maximal aerobic oxygen consumption ( ) in B. penicillata; associated with this is a skeletal muscle mass of 44% of body mass. Ten muscles were sampled to estimate the total mitochondrial and capillary volume of the locomotor muscles. Values in B. penicillata were similar to those in M. rufus and in athletic placentals. This small hopper had high muscle mitochondrial volume densities (7.1-11.9%) and both a large total capillary volume (6 ml kg(-1) body mass) and total capillary erythrocyte volume (3.2 ml kg(-1)). Apparently, a considerable aerobic capacity is required to achieve the benefits of the extended stride in fast hopping. Of note, the ratio of to total muscle mitochondrial volume in B. penicillata was 4.9 ml O(2) min(-1) ml(-1). Similar values occur in M. rufus and also placental mammals generally, not only athletic species. If such relationships occur in other marsupials, a fundamental structure-function relationship for oxygen delivery to muscles likely originated with or before the earliest mammals.

Fine Structure of Anomalously Intense Pulses of PSR J0814+7429 Radio Emission in the Decameter Range

NASA Astrophysics Data System (ADS)

Skoryk, A. O.; Ulyanov, O. M.; Zakharenko, V. V.; Shevtsova, A. I.; Vasylieva, I. Y.; Plakhov, M. S.; Kravtsov, I. M.

2017-06-01

Purpose: The fine structure of the anomalously intense pulses of PSR J0814+7429 (B0809+74) has been studied. The pulsar radio emission fine structure is investigated to determine its parameters in the lowest part of spectrum available for groundbased observations. Design/methodology/approach: The scattering measure in the interstellar plasma have been estimated using the spectral and correlation analyses of pulsar data recorded by the UTR-2 radio telescope. Results: Two characteristic time scales of the anomalously intense pulses fine structure of the PSR J0814+7429 radio emission have been found. The strongest pulses of this pulsar in the decameter range can have a duration of about t 2÷3 ms. These pulses are emitted in short series. In some cases, they are emitted over the low-intensity plateau consisting of the “long” subpulse component. Conclusions: The narrowest correlation scale of pulsar J0814+7429 radio emission corresponds to the doubled scattering time constant of the interstellar medium impulse response. Broader scale of the fine structure of its radio emission can be explained by the radiation of a short series of narrow pulses or relatively broad pulses inside this pulsar magnetosphere.

Chimaeric sounds reveal dichotomies in auditory perception

PubMed Central

Smith, Zachary M.; Delgutte, Bertrand; Oxenham, Andrew J.

2008-01-01

By Fourier's theorem1, signals can be decomposed into a sum of sinusoids of different frequencies. This is especially relevant for hearing, because the inner ear performs a form of mechanical Fourier transform by mapping frequencies along the length of the cochlear partition. An alternative signal decomposition, originated by Hilbert2, is to factor a signal into the product of a slowly varying envelope and a rapidly varying fine time structure. Neurons in the auditory brainstem3–6 sensitive to these features have been found in mammalian physiological studies. To investigate the relative perceptual importance of envelope and fine structure, we synthesized stimuli that we call ‘auditory chimaeras’, which have the envelope of one sound and the fine structure of another. Here we show that the envelope is most important for speech reception, and the fine structure is most important for pitch perception and sound localization. When the two features are in conflict, the sound of speech is heard at a location determined by the fine structure, but the words are identified according to the envelope. This finding reveals a possible acoustic basis for the hypothesized ‘what’ and ‘where’ pathways in the auditory cortex7–10. PMID:11882898

Estimation of structural film viscosity based on the bubble rise method in a nanofluid.

PubMed

Cho, Heon Ki; Nikolov, Alex D; Wasan, Darsh T

2018-04-15

When a single bubble moves at a very low capillary number (10 -7 ) through a liquid with dispersed nanoparticles (nanofluid) inside a vertical tube/capillary, a film is formed between the bubble surface and the tube wall and the nanoparticles self-layer inside the confined film. We measured the film thickness using reflected light interferometry. We calculated the film structural energy isotherm vs. the film thickness from the film-meniscus contact angle measurements using the reflected light interferometric method. Based on the experimental measurement of the film thickness and the calculated values of the film structural energy barrier, we estimated the structural film viscosity vs. the film thickness using the Frenkel approach. Because of the nanoparticle film self-layering phenomenon, we observed a gradual increase in the film viscosity with the decreasing film thickness. However, we observed a significant increase in the film viscosity accompanied by a step-wise decrease in the bubble velocity when the film thickness decreased from 3 to 2 particle layers due to the structural transition in the film. Copyright © 2018 Elsevier Inc. All rights reserved.

The Effect of Quantum-Mechanical Interference on Precise Measurements of the n = 2 Triplet P Fine Structure of Helium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marsman, A.; Horbatsch, M.; Hessels, E. A., E-mail: hessels@yorku.ca

2015-09-15

For many decades, improvements in both theory and experiment of the fine structure of the n = 2 triplet P levels of helium have allowed for an increasingly precise determination of the fine-structure constant. Recently, it has been observed that quantum-mechanical interference between neighboring resonances can cause significant shifts, even if such neighboring resonances are separated by thousands of natural widths. The shifts depend in detail on the experimental method used for the measurement, as well as the specific experimental parameters employed. Here, we review how these shifts apply for the most precise measurements of the helium 2{sup 3}P fine-structuremore » intervals.« less

Sample-based synthesis of two-scale structures with anisotropy

DOE PAGES

Liu, Xingchen; Shapiro, Vadim

2017-05-19

A vast majority of natural or synthetic materials are characterized by their anisotropic properties, such as stiffness. Such anisotropy is effected by the spatial distribution of the fine-scale structure and/or anisotropy of the constituent phases at a finer scale. In design, proper control of the anisotropy may greatly enhance the efficiency and performance of synthesized structures. In this paper, we propose a sample-based two-scale structure synthesis approach that explicitly controls anisotropic effective material properties of the structure on the coarse scale by orienting sampled material neighborhoods at the fine scale. We first characterize the non-uniform orientations distribution of the samplemore » structure by showing that the principal axes of an orthotropic material may be determined by the eigenvalue decomposition of its effective stiffness tensor. Such effective stiffness tensors can be efficiently estimated based on the two-point correlation functions of the fine-scale structures. Then we synthesize the two-scale structure by rotating fine-scale structures from the sample to follow a given target orientation field. Finally, the effectiveness of the proposed approach is demonstrated through examples in both 2D and 3D.« less

Sample-based synthesis of two-scale structures with anisotropy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Xingchen; Shapiro, Vadim

A vast majority of natural or synthetic materials are characterized by their anisotropic properties, such as stiffness. Such anisotropy is effected by the spatial distribution of the fine-scale structure and/or anisotropy of the constituent phases at a finer scale. In design, proper control of the anisotropy may greatly enhance the efficiency and performance of synthesized structures. In this paper, we propose a sample-based two-scale structure synthesis approach that explicitly controls anisotropic effective material properties of the structure on the coarse scale by orienting sampled material neighborhoods at the fine scale. We first characterize the non-uniform orientations distribution of the samplemore » structure by showing that the principal axes of an orthotropic material may be determined by the eigenvalue decomposition of its effective stiffness tensor. Such effective stiffness tensors can be efficiently estimated based on the two-point correlation functions of the fine-scale structures. Then we synthesize the two-scale structure by rotating fine-scale structures from the sample to follow a given target orientation field. Finally, the effectiveness of the proposed approach is demonstrated through examples in both 2D and 3D.« less

Silica- and germania-based dual-ligand sol-gel organic-inorganic hybrid sorbents combining superhydrophobicity and π-π interaction. The role of inorganic substrate in sol-gel capillary microextraction.

PubMed

Seyyal, Emre; Malik, Abdul

2017-04-29

Principles of sol-gel chemistry were utilized to create silica- and germania-based dual-ligand surface-bonded sol-gel coatings providing enhanced performance in capillary microextraction (CME) through a combination of ligand superhydrophobicity and π-π interaction. These organic-inorganic hybrid coatings were prepared using sol-gel precursors with bonded perfluorododecyl (PF-C 12 ) and phenethyl (PhE) ligands. Here, the ability of the PF-C 12 ligand to provide enhanced hydrophobic interaction was advantageously combined with π-π interaction capability of the PhE moiety to attain the desired sorbent performance in CME. The effect of the inorganic sorbent component on microextraction performance of was explored by comparing microextraction characteristics of silica- and germania-based sol-gel sorbents. The germania-based dual-ligand sol-gel sorbent demonstrated superior CME performance compared to its silica-based counterpart. Thermogravimetric analysis (TGA) of the created silica- and germania-based dual-ligand sol-gel sorbents suggested higher carbon loading on the germania-based sorbent. This might be indicative of more effective condensation of the organic ligand-bearing sol-gel-active chemical species to the germania-based sol-gel network (than to its silica-based counterpart) evolving in the sol solution. The type and concentration of the organic ligands were varied in the sol-gel sorbents to fine-tune extraction selectivity toward different classes of analytes. Specific extraction (SE) values were used for an objective comparison of the prepared sol-gel CME sorbents. The sorbents with higher content of PF-C 12 showed remarkable affinity for aliphatic hydrocarbons. Compared to their single-ligand sol-gel counterparts, the dual-ligand sol-gel coatings demonstrated significantly superior CME performance in the extraction of alkylbenzenes, providing up to ∼65.0% higher SE values. The prepared sol-gel CME coatings provided low ng L -1 limit of detections (LOD) (4.2-26.3 ng L -1 ) for environmentally important analytes including polycyclic aromatic hydrocarbons, ketones and aliphatic hydrocarbons. In CME-GC experiments (n = 5), the capillary-to-capillary RSD value was ∼2.1%; such a low RSD value is indicative of excellent reproducibility of the sol-gel method used for the preparation of these CME coatings. The dual-ligand sol-gel coating provided stable performance in capillary microextraction of analytes from saline samples. Copyright © 2017 Elsevier B.V. All rights reserved.

Reservoir characterization and preliminary modeling of deltaic facies, lower Wilcox, Concordia Parish, Louisiana

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schenewerk, P.; Goddard, D.; Echols, J.

The decline in production in several fields in Concordia Parish, Louisiana, has created interest in the economic feasibility of producing the remaining bypassed oil in the lower Wilcox Group. One of these fields, Bee Brake, has been one of the more prolific oil-producing fields in east-central Louisiana. The producing interval, the Minter sandstones, at a depth of about 6,775 ft typically consists of an upper Bee Brake sandstone and a lower Angelina sandstone. A detailed study of a conventional core in the center of the field reveals a 15-ft-thick Minter interval bounded above and below by sealing shales and lignitesmore » of lower delta plain marsh facies. The upper 4-ft-thick Bee Brake is a very fine silty sandstone with characteristics of a small overbank or crevasse splay deposit. The lower 3-ft-thick oil-producing Angelina sandstone consists of very fine and fine sandstone of probable overbank or crevasse facies. Cumulative production from the Angelina is about 1.8 million stock-tank barrels of oil. Special core analysis data (capillary pressure, relative permeability, and waterflood recovery) have been used to develop a simulation model of the two reservoirs in the Minter. This model incorporates the geologic and engineering complexities noted during evaluation of the field area. Operators can use the model results in this field to design an optimal development plan for enhanced recovery.« less

Coupling fine-scale root and canopy structure using ground-based remote sensing

Treesearch

Brady Hardiman; Christopher Gough; John Butnor; Gil Bohrer; Matteo Detto; Peter Curtis

2017-01-01

Ecosystem physical structure, defined by the quantity and spatial distribution of biomass, influences a range of ecosystem functions. Remote sensing tools permit the non-destructive characterization of canopy and root features, potentially providing opportunities to link above- and belowground structure at fine spatial resolution in...

Reconfigurable modified surface layers using plasma capillaries around the neutral inclusion regime

DOE Office of Scientific and Technical Information (OSTI.GOV)

Varault, S.; Universite Paul Sabatier—CNRS-Laplace 118, Route de Narbonne, F-31062 Toulouse Cedex 9; Gabard, B.

We show both theoretically and experimentally reconfigurable properties achieved by plasma inclusions placed in modified surface layers generally used to tailor the transmission and beaming properties of electromagnetic bandgap based waveguiding structures. A proper parametrization of the plasma capillaries allows to reach the neutral inclusion regime, where the inclusions appear to be electromagnetically transparent, letting the surface mode characteristics unaltered. Varying the electron density of the plasma inclusions provoques small perturbations around this peculiar regime, and we observe significant modifications of the transmission/beaming properties. This offers a way to dynamically select the enhanced transmission frequency or to modify the radiationmore » pattern of the structure, depending on whether the modified surface layer is placed at the entrance/exit of the waveguide.« less

Formation of fine {gamma} grain structure through fine {alpha}{sub 2}/{gamma} lamellar structure in Ti-rich TiAl alloy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kumagai, T.; Abe, E.; Nakamura, M.

1997-12-31

Microstructural development of an extremely fine {alpha}{sub 2}-Ti{sub 32}Al/{gamma}-TiAl lamellar structure, which was formed by ice water quenching after solution-treatment in a high-temperature {alpha}-Ti phase field for a long period of time, was examined during isothermal treatment. In an as-quenched Ti-48at.%Al alloy, the massively transformed {gamma} ({gamma}{sub m}) and untransformed (meaning massively untransformed) fine {alpha}{sub 2}/{gamma} lamellar regions were observed. Fine {gamma} grains, which were similar to {gamma}{sub m}, were generated both within the fine {alpha}{sub 2}/{gamma} lamellae and at the boundary area between the {gamma}{sub m} and the fine {alpha}{sub 2}/{gamma} lamellar regions by aging at low-temperature (1,173 K)more » for a short time (180s). Further aging (1.8ks) caused the coarsening of these newly generated fine {gamma} grains. On the other hand, the coarsening of the {gamma} grains occurred by a high-temperature (1,323 K) aging treatment even for 180s. Fine {alpha}{sub 2} plates and particles, which were aligned to a particular direction, were observed in the {gamma} grain interiors, indicating that the newly generated {gamma} grains grew at the expense of the fine {alpha}{sub 2}/{gamma} lamellae. It can be considered that the {gamma} grain formation through the fine {alpha}{sub 2}/{gamma} lamellae is closely related to the {alpha}{sub 2}{yields}{gamma} reaction of the {alpha}{sub 2} plates sandwiched by the {gamma} plates, and needs the fast heating rate enough to overcome the {alpha}{sub 2}/{gamma}{yields}{gamma}/{gamma} lamellae reaction.« less

Fine Structure of Trious and Excitons in Single GaAs Quantum Dots

DTIC Science & Technology

2002-08-30

RAPID COMMUNICATIONS PHYSICAL REVIEW B 66, 081310~R! ~2002!Fine structure of trions and excitons in single GaAs quantum dots J. G. Tischler, A. S ...fine structure of single localized excitons and trions. DOI: 10.1103/PhysRevB.66.081310 PACS number~ s !: 78.67.Hc, 73.21.2b, 71.35.2yAlthough the...AUTHOR( S ) 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME( S ) AND ADDRESS(ES) Naval Research Laboratory

Monte Carlo Simulations of Electron Energy-Loss Spectra with the Addition of Fine Structure from Density Functional Theory Calculations.

PubMed

Attarian Shandiz, Mohammad; Guinel, Maxime J-F; Ahmadi, Majid; Gauvin, Raynald

2016-02-01

A new approach is presented to introduce the fine structure of core-loss excitations into the electron energy-loss spectra of ionization edges by Monte Carlo simulations based on an optical oscillator model. The optical oscillator strength is refined using the calculated electron energy-loss near-edge structure by density functional theory calculations. This approach can predict the effects of multiple scattering and thickness on the fine structure of ionization edges. In addition, effects of the fitting range for background removal and the integration range under the ionization edge on signal-to-noise ratio are investigated.

Formation of natural gas hydrates in marine sediments. Gas hydrate growth and stability conditioned by host sediment properties

USGS Publications Warehouse

Clennell, M.B.; Henry, P.; Hovland, M.; Booth, J.S.; Winters, W.J.; Thomas, M.

2000-01-01

The stability conditions of submarine gas hydrates (methane clathrates) are largely dictated by pressure, temperature, gas composition, and pore water salinity. However, the physical properties and surface chemistry of the host sediments also affect the thermodynamic state, growth kinetics, spatial distributions, and growth forms of clathrates. Our model presumes that gas hydrate behaves in a way analogous to ice in the pores of a freezing soil, where capillary forces influence the energy balance. Hydrate growth is inhibited within fine-grained sediments because of the excess internal phase pressure of small crystals with high surface curvature that coexist with liquid water in small pores. Therefore, the base of gas hydrate stability in a sequence of fine sediments is predicted by our model to occur at a lower temperature, and so nearer to the seabed than would be calculated from bulk thermodynamic equilibrium. The growth forms commonly observed in hydrate samples recovered from marine sediments (nodules, sheets, and lenses in muds; cements in sand and ash layers) can be explained by a requirement to minimize the excess of mechanical and surface energy in the system.

A three-dimensional neural spheroid model for capillary-like network formation.

PubMed

Boutin, Molly E; Kramer, Liana L; Livi, Liane L; Brown, Tyler; Moore, Christopher; Hoffman-Kim, Diane

2018-04-01

In vitro three-dimensional neural spheroid models have an in vivo-like cell density, and have the potential to reduce animal usage and increase experimental throughput. The aim of this study was to establish a spheroid model to study the formation of capillary-like networks in a three-dimensional environment that incorporates both neuronal and glial cell types, and does not require exogenous vasculogenic growth factors. We created self-assembled, scaffold-free cellular spheroids using primary-derived postnatal rodent cortex as a cell source. The interactions between relevant neural cell types, basement membrane proteins, and endothelial cells were characterized by immunohistochemistry. Transmission electron microscopy was used to determine if endothelial network structures had lumens. Endothelial cells within cortical spheroids assembled into capillary-like networks with lumens. Networks were surrounded by basement membrane proteins, including laminin, fibronectin and collagen IV, as well as key neurovascular cell types. Existing in vitro models of the cortical neurovascular environment study monolayers of endothelial cells, either on transwell inserts or coating cellular spheroids. These models are not well suited to study vasculogenesis, a process hallmarked by endothelial cell cord formation and subsequent lumenization. The neural spheroid is a new model to study the formation of endothelial cell capillary-like structures in vitro within a high cell density three-dimensional environment that contains both neuronal and glial populations. This model can be applied to investigate vascular assembly in healthy or disease states, such as stroke, traumatic brain injury, or neurodegenerative disorders. Copyright © 2017 Elsevier B.V. All rights reserved.

Sodium metabisulphite, a preservative agent, decreases the heart capillary volume and length, and curcumin, the main component of Curcuma longa, cannot protect it.

PubMed

Noorafshan, A; Asadi-Golshan, R; Monjezi, S; Karbalay-Doust, S

2014-01-01

Sodium metabisulphite is used as an antioxidant agent in many pharmaceutical formulations. It is extensively used as a food preservative and disinfectant. It has been demonstrated that sulphite exposure can affect some organs. Curcumin, the main element of Curcuma longa, has been identified to have multiple protective properties. The present study extends the earlier works to quantitative evaluation of the effects of sulphite and curcumin on the heart structure using stereological methods. In this study, 28 rats were randomly divided into four experimental groups. The rats in groups I to IV received distilled water (group I), sodium metabisulphite (25 mg/ kg/day) (group II), curcumin (100 mg/kg/day) (group III), and sodium metabisulphite+curcumin (group IV), respectively, for 8 weeks. The left ventricle was subjected to stereological methods to estimate the quantitative parameters of the myocardium. A 20 % decrease was observed in the total volume of ventricular tissue in the sulphite-treated animals compared to the distilled water treatment (P < 0.02). Also, the volume and length of the capillaries were reduced by 43 % on average in the sulphite-treated rats in comparison to the distilled water-treated animals (P < 0.02). However, no significant change was seen in the mean and total volume of the myocardium and the cavity and diameter of the capillaries after sulphite ingestion. Treatment with curcumin did not protect the animals against the structural changes of the ventricle. Sulphite, as a preservative food agent, reduced the length and volume of the ventricular capillaries and curcumin could not protect them.

A capillary zone electrophoresis method for detection of Apolipoprotein C-III glycoforms and other related artifactually modified species.

PubMed

Ruel, Coralie; Morani, Marco; Bruneel, Arnaud; Junot, Christophe; Taverna, Myriam; Fenaille, François; Tran, Nguyet Thuy

2018-01-12

ApolipoproteinC-III (ApoC-III) is a human plasma glycoprotein whose O-glycosylation can be altered as a result of congenital disorders of glycosylation (CDG). ApoC-III exhibits three major glycoforms whose relative quantification is of utmost importance for the diagnosis of CDG patients. Considering the very close structures of these glycoforms and their tendency to adsorb on the capillary, a thorough optimization of capillary electrophoresis (CE) parameters including preconditioning and in-between rinsing procedures was required to efficiently separate all the ApoC-III glycoforms. Permanent coatings did not contribute to high resolution separations. A fast and reliable method based on a bare-silica capillary combining the effect of urea and diamine additives allowed to separate up to six different ApoC-III forms. We demonstrated by a combination of MALDI-TOF mass spectrometry (MS) analyses and CE of intact and neuraminidase-treated samples that this method well resolved glycoforms differing not only by their sialylation degree but also by carbamylation state, an undesired chemical modification of primary amines. This method allowed to demonstrate the carbamylation of ApoC-III glycoforms for the first time. Our CZE method proved robust and accurate with excellent intermediate precision regarding migration times (RSDs < 0.7%) while RSDs for peak areas were less than 5%. Finally, the quality of three distinct batches of commercial ApoC-III obtained from different suppliers was assessed and compared. Quite similar but highly structurally heterogeneous ApoC-III profiles were observed for these samples. Copyright © 2017 Elsevier B.V. All rights reserved.

A simulation for gravity fine structure recovery from high-low GRAVSAT SST data

NASA Technical Reports Server (NTRS)

Estes, R. H.; Lancaster, E. R.

1976-01-01

Covariance error analysis techniques were applied to investigate estimation strategies for the high-low SST mission for accurate local recovery of gravitational fine structure, considering the aliasing effects of unsolved for parameters. Surface density blocks of 5 deg x 5 deg and 2 1/2 deg x 2 1/2 deg resolution were utilized to represent the high order geopotential with the drag-free GRAVSAT configured in a nearly circular polar orbit at 250 km. altitude. GEOPAUSE and geosynchronous satellites were considered as high relay spacecraft. It is demonstrated that knowledge of gravitational fine structure can be significantly improved at 5 deg x 5 deg resolution using SST data from a high-low configuration with reasonably accurate orbits for the low GRAVSAT. The gravity fine structure recoverability of the high-low SST mission is compared with the low-low configuration and shown to be superior.

Revisiting place and temporal theories of pitch

PubMed Central

2014-01-01

The nature of pitch and its neural coding have been studied for over a century. A popular debate has revolved around the question of whether pitch is coded via “place” cues in the cochlea, or via timing cues in the auditory nerve. In the most recent incarnation of this debate, the role of temporal fine structure has been emphasized in conveying important pitch and speech information, particularly because the lack of temporal fine structure coding in cochlear implants might explain some of the difficulties faced by cochlear implant users in perceiving music and pitch contours in speech. In addition, some studies have postulated that hearing-impaired listeners may have a specific deficit related to processing temporal fine structure. This article reviews some of the recent literature surrounding the debate, and argues that much of the recent evidence suggesting the importance of temporal fine structure processing can also be accounted for using spectral (place) or temporal-envelope cues. PMID:25364292

Simplifying the design of microstructured optical fibre pressure sensors.

PubMed

Osório, Jonas H; Chesini, Giancarlo; Serrão, Valdir A; Franco, Marcos A R; Cordeiro, Cristiano M B

2017-06-07

In this paper, we propose a way to simplify the design of microstructured optical fibres with high sensitivity to applied pressure. The use of a capillary fibre with an embedded core allows the exploration of the pressure-induced material birefringence due to the capillary wall displacements and the photoelastic effect. An analytical description of pressure-induced material birefringence is provided, and fibre modal characteristics are explored through numerical simulations. Moreover, a capillary fibre with an embedded core is fabricated and used to probe pressure variations. Even though the embedded-core fibre has a non-optimized structure, measurements showed a pressure sensitivity of (1.04 ± 0.01) nm/bar, which compares well with more complex, specially designed fibre geometries reported in the literature. These results demonstrate that this geometry enables a novel route towards the simplification of microstructured fibre-based pressure sensors.

Biofabrication of Tobacco mosaic virus-nanoscaffolded supercapacitors via temporal capillary microfluidics

NASA Astrophysics Data System (ADS)

Zang, Faheng; Chu, Sangwook; Gerasopoulos, Konstantinos; Culver, James N.; Ghodssi, Reza

2017-06-01

This paper reports the implementation of temporal capillary microfluidic patterns and biological nanoscaffolds in autonomous microfabrication of nanostructured symmetric electrochemical supercapacitors. A photoresist layer was first patterned on the substrate, forming a capillary microfluidics layer with two separated interdigitated microchannels. Tobacco mosaic virus (TMV) macromolecules suspended in solution are autonomously delivered into the microfluidics, and form a dense bio-nanoscaffolds layer within an hour. This TMV layer is utilized in the electroless plating and thermal oxidation for creating nanostructured NiO supercapacitor. The galvanostatic charge/discharge cycle showed a 3.6-fold increase in areal capacitance for the nanostructured electrode compared to planar structures. The rapid creation of nanostructure-textured microdevices with only simple photolithography and bionanostructure self-assembly can completely eliminate the needs for sophisticated synthesis or deposition processes. This method will contribute to rapid prototyping of wide range of nano-/micro-devices with enhanced performance.

Strategies for the capillary electrophoretic separation of indole alkaloids in Psilocybe semilanceata.

PubMed

Pedersen-Bjergaard, S; Rasmussen, K E; Sannes, E

1998-01-01

While the hallucinogenic mushrooms Psilocybe semilanceata have previously been analyzed for the indole alkaloids psilocybin and baeocystin by capillary zone electrophoresis (CZE) at pH 11.5, the present work focused on the development of an alternative and complementary capillary electrophoretic method for their identification. Owing to their structural similarity and zwitterionic nature, the compounds were difficult to resolve based on different interactions with cationic or anionic micelles. However, while the attempts with micellar electrokinetic chromatography (MEKC) were unsuccessful, rapid derivatization with propyl chloroformate and reanalysis by CZE at pH 11.5 was effective to support identification of the two indole alkaloids. Psilocin was difficult to analyze by CZE at pH 11.5 owing to comigration with the electroosmotic flow. For this compound, the pH of the running buffer was reduced to 7.2 to effectively enhance the electrophoretic mobility.

Electrochemistry and capillary condensation theory reveal the mechanism of corrosion in dense porous media.

PubMed

Stefanoni, Matteo; Angst, Ueli M; Elsener, Bernhard

2018-05-09

Corrosion in carbonated concrete is an example of corrosion in dense porous media of tremendous socio-economic and scientific relevance. The widespread research endeavors to develop novel, environmentally friendly cements raise questions regarding their ability to protect the embedded steel from corrosion. Here, we propose a fundamentally new approach to explain the scientific mechanism of corrosion kinetics in dense porous media. The main strength of our model lies in its simplicity and in combining the capillary condensation theory with electrochemistry. This reveals that capillary condensation in the pore structure defines the electrochemically active steel surface, whose variability upon changes in exposure relative humidity is accountable for the wide variability in measured corrosion rates. We performed experiments that quantify this effect and find good agreement with the theory. Our findings are essential to devise predictive models for the corrosion performance, needed to guarantee the safety and sustainability of traditional and future cements.

Controlled crosslinking of trimethylolpropane trimethacrylate for preparation of organic monolithic columns for capillary liquid chromatography.

PubMed

Gama, Mariana R; Aggarwal, Pankaj; Lee, Milton L; Bottoli, Carla B G

2017-11-01

Organic monolithic columns based on single crosslinking of trimethylolpropane trimethacrylate (TRIM) monomer were prepared in a single step by living/controlled free-radical polymerization. Full optimization of the preparation, such as using different percentages of TRIM and different amounts of radical promoter as well as various porogen solvents were explored. The resulting monolithic columns were characterized by scanning electronic microscopy and nitrogen sorption for structure morphology studies and surface area measurements, respectively. Using capillary liquid chromatography, 150 μm i.d. columns were applied to separate a mixture of small hydrophobic molecules. The results indicated that column performance is highly sensitive to the type and the amount of porogen solvents used in the polymerization mixture composition. Good resolution factors and methylene selectivity were obtained, indicating the promising potential of this material for capillary liquid chromatography separations. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Usage of Crushed Concrete Fines in Decorative Concrete

NASA Astrophysics Data System (ADS)

Pilipenko, Anton; Bazhenova, Sofia

2017-10-01

The article is devoted to the questions of usage of crushed concrete fines from concrete scrap for the production of high-quality decorative composite materials based on mixed binder. The main problem in the application of crushed concrete in the manufacture of decorative concrete products is extremely low decorative properties of crushed concrete fines itself, as well as concrete products based on them. However, crushed concrete fines could have a positive impact on the structure of the concrete matrix and could improve the environmental and economic characteristics of the concrete products. Dust fraction of crushed concrete fines contains non-hydrated cement grains, which can be opened in screening process due to the low strength of the contact zone between the hydrated and non-hydrated cement. In addition, the screening process could increase activity of the crushed concrete fines, so it can be used as a fine aggregate and filler for concrete mixes. Previous studies have shown that the effect of the usage of the crushed concrete fines is small and does not allow to obtain concrete products with high strength. However, it is possible to improve the efficiency of the crushed concrete fines as a filler due to the complex of measures prior to mixing. Such measures may include a preliminary mechanochemical activation of the binder (cement binder, iron oxide pigment, silica fume and crushed concrete fines), as well as the usage of polycarboxylate superplasticizers. The development of specific surface area of activated crushed concrete fines ensures strong adhesion between grains of binder and filler during the formation of cement stone matrix. The particle size distribution of the crushed concrete fines could achieve the densest structure of cement stone matrix and improve its resistance to environmental effects. The authors examined the mechanisms of structure of concrete products with crushed concrete fines as a filler. The results of studies of the properties of the crushed concrete fines were provided. It is shown that the admixture of the crushed concrete fines has little effect on the colour characteristics of the decorative concrete products. The preferred options to improve the surfaces of decorative concrete are also proposed.

Soil-Moisture Retention Curves, Capillary Pressure Curves, and Mercury Porosimetry: A Theoretical and Computational Investigation of the Determination of the Geometric Properties of the Pore Space

NASA Astrophysics Data System (ADS)

Strand, T. E.; Wang, H. F.

2003-12-01

Immiscible displacement protocols have long been used to infer the geometric properties of the void space in granular porous media. The three most commonly used experimental techniques are the measurement of soil-moisture retention curves and relative permeability-capillary pressure-saturation relations, as well as mercury intrusion porosimetry experiments. A coupled theoretical and computational investigation was performed that provides insight into the limitations associated with each technique and quantifies the relationship between experimental observations and the geometric properties of the void space. It is demonstrated that the inference of the pore space geometry from both mercury porosimetry experiments and measurements of capillary pressure curves is influenced by trapping/mobilization phenomena and subject to scaling behavior. In addition, both techniques also assume that the capillary pressure at a location on the meniscus can be approximated by a pressure difference across a region or sample. For example, when performing capillary pressure measurements, the capillary pressure, taken to be the difference between the injected fluid pressure at the inlet and the defending fluid pressure at the outlet, is increased in a series of small steps and the fluid saturation is measured each time the system reaches steady. Regions of defending fluid that become entrapped by the invading fluid can be subsequently mobilized at higher flow rates (capillary pressures), contributing to a scale-dependence of the capillary pressure-saturation curve that complicates the determination of the properties of the pore space. This scale-dependence is particularly problematic for measurements performed at the core scale. Mercury porosimetry experiments are subject to similar limitations. Trapped regions of defending fluid are also present during the measurement of soil-moisture retention curves, but the effects of scaling behavior on the evaluation of the pore space properties from the immiscible displacement structure are much simpler to account for due to the control of mobilization phenomena. Some mobilization may occur due to film flow, but this can be limited by keeping time scales relatively small or exploited at longer time scales in order to quantify the rate of film flow. Computer simulations of gradient-stabilized drainage and imbibition to the (respective) equilibrium positions were performed using a pore-scale modified invasion percolation (MIP) model in order to quantify the relationship between the saturation profile and the geometric properties of the void space. These simulations are similar to the experimental measurement of soil-moisture retention curves. Results show that the equilibrium height and the width of the equilibrium fringe depend on two length scale distributions, one controlling the imbibition equilibrium structure and the other controlling the drainage structure. The equilibrium height is related to the mean value of the appropriate distribution as described by Jurin's law, and the width of the equilibrium fringe scales as a function of a combined parameter, the Bond number, Bo, divided by the coefficient of variation (cov). Simulations also demonstrate that the apparent radius distribution obtained from saturation profiles using direct inversion by Jurin's law is a subset of the actual distribution in the porous medium. The relationship between the apparent and actual radius distributions is quantified in terms of the combined parameter, Bo/cov, and the mean coordination number of the porous medium.

P-polarized reflectance spectroscopy: A high sensitive real-time monitoring technique to study surface kinetics under steady state epitaxial deposition conditions

NASA Technical Reports Server (NTRS)

Dietz, Nikolaus; Bachmann, Klaus J.

1995-01-01

This paper describes the results of real-time optical monitoring of epitaxial growth processes by p-polarized reflectance spectroscopy (PRS) using a single wavelength application under pulsed chemical beam epitaxy (PCBE) condition. The high surface sensitivity of PRS allows the monitoring of submonolayer precursors coverage on the surface as shown for GaP homoepitaxy and GaP on Si heteroepitaxy as examples. In the case of heteroepitaxy, the growth rate and optical properties are revealed by PRS using interference oscillations as they occur during growth. Super-imposed on these interference oscillations, the PRS signal exhibits a fine structure caused by the periodic alteration of the surface chemistry by the pulsed supply of chemical precursors. This fine structure is modeled under conditions where the surface chemistry cycles between phosphorus supersaturated and phosphorus depleted surfaces. The mathematical model describes the fine structure using a surface layer that increases during the tertiarybutyl phosphine (TBP) supply and decreases during and after the triethylgallium (TEG) pulse, which increases the growing GaP film thickness. The imaginary part of the dielectric function of the surface layer is revealed from the turning points in the fine structure, where the optical response to the first precursor pulse in the cycle sequence changes sign. The amplitude of the fine structure is determined by the surface layer thickness and the complex dielectric functions for the surface layer with the underlying bulk film. Surface kinetic data can be obtained by analyzing the rise and decay transients of the fine structure.

Comparative and Developmental Anatomy of Cardiac Lymphatics

PubMed Central

Ratajska, A.; Gula, G.; Flaht-Zabost, A.; Czarnowska, E.; Ciszek, B.; Jankowska-Steifer, E.; Niderla-Bielinska, J.; Radomska-Lesniewska, D.

2014-01-01

The role of the cardiac lymphatic system has been recently appreciated since lymphatic disturbances take part in various heart pathologies. This review presents the current knowledge about normal anatomy and structure of lymphatics and their prenatal development for a better understanding of the proper functioning of this system in relation to coronary circulation. Lymphatics of the heart consist of terminal capillaries of various diameters, capillary plexuses that drain continuously subendocardial, myocardial, and subepicardial areas, and draining (collecting) vessels that lead the lymph out of the heart. There are interspecies differences in the distribution of lymphatic capillaries, especially near the valves, as well as differences in the routes and number of draining vessels. In some species, subendocardial areas contain fewer lymphatic capillaries as compared to subepicardial parts of the heart. In all species there is at least one collector vessel draining lymph from the subepicardial plexuses and running along the anterior interventricular septum under the left auricle and further along the pulmonary trunk outside the heart and terminating in the right venous angle. The second collector assumes a different route in various species. In most mammalian species the collectors run along major branches of coronary arteries, have valves and a discontinuous layer of smooth muscle cells. PMID:24592145

Comparative and developmental anatomy of cardiac lymphatics.

PubMed

Ratajska, A; Gula, G; Flaht-Zabost, A; Czarnowska, E; Ciszek, B; Jankowska-Steifer, E; Niderla-Bielinska, J; Radomska-Lesniewska, D

2014-01-01

The role of the cardiac lymphatic system has been recently appreciated since lymphatic disturbances take part in various heart pathologies. This review presents the current knowledge about normal anatomy and structure of lymphatics and their prenatal development for a better understanding of the proper functioning of this system in relation to coronary circulation. Lymphatics of the heart consist of terminal capillaries of various diameters, capillary plexuses that drain continuously subendocardial, myocardial, and subepicardial areas, and draining (collecting) vessels that lead the lymph out of the heart. There are interspecies differences in the distribution of lymphatic capillaries, especially near the valves, as well as differences in the routes and number of draining vessels. In some species, subendocardial areas contain fewer lymphatic capillaries as compared to subepicardial parts of the heart. In all species there is at least one collector vessel draining lymph from the subepicardial plexuses and running along the anterior interventricular septum under the left auricle and further along the pulmonary trunk outside the heart and terminating in the right venous angle. The second collector assumes a different route in various species. In most mammalian species the collectors run along major branches of coronary arteries, have valves and a discontinuous layer of smooth muscle cells.

A new structure of permeable pavement for mitigating urban heat island.

PubMed

Liu, Yong; Li, Tian; Peng, Hangyu

2018-09-01

The urban heat island (UHI) effect has been a great threat to human habitation, and how to mitigate this problem has been a global concern over decades. This paper addresses the cooling effect of a novel permeable pavement called evaporation-enhancing permeable pavement, which has capillary columns in aggregate and a liner at the bottom. To explore the efficiency of mitigating the UHI, bench-scale permeable pavement units with capillary columns were developed and compared with conventional permeable pavement. Criteria of capillary capacities of the column, evaporation rates, and surface temperature of the pavements were monitored under simulated rainfall and Shanghai local weather conditions. Results show the capillary column was important in increasing evaporation by lifting water from the bottom to the surface, and the evaporation-enhancing permeable pavement was cooler than a conventional permeable pavement by as much as 9.4°C during the experimental period. Moreover, the cooling effect of the former pavement could persist more than seven days under the condition of no further rainfall. Statistical analysis result reveals that evaporation-enhancing permeable pavement can mitigate the UHI effect significantly more than a conventional permeable pavement. Copyright © 2018 Elsevier B.V. All rights reserved.

Elevated blood pressure in preterm-born offspring associates with a distinct antiangiogenic state and microvascular abnormalities in adult life.

PubMed

Lewandowski, Adam J; Davis, Esther F; Yu, Grace; Digby, Janet E; Boardman, Henry; Whitworth, Polly; Singhal, Atul; Lucas, Alan; McCormick, Kenny; Shore, Angela C; Leeson, Paul

2015-03-01

Preterm-born individuals have elevated blood pressure. We tested the hypothesis that this associates with an enhanced antiangiogenic circulating profile and that this association is mediated by variations in capillary density. We studied 204 adults aged 25 years (range, 20-30 years), of which 102 had been followed up prospectively since very preterm birth (mean gestational age, 30.3±2.5 weeks) and 102 were born term to uncomplicated pregnancies. A panel of circulating biomarkers, including soluble endoglin and soluble fms-like tyrosine kinase-1, were compared between groups and related to perinatal history and adult cardiovascular risk. Associations with cardiovascular phenotype were studied in 90 individuals who had undergone detailed assessment of microvascular, macrovascular, and cardiac structure and function. Preterm-born individuals had elevations in soluble endoglin (5.64±1.03 versus 4.06±0.85 ng/mL; P<0.001) and soluble fms-like tyrosine kinase-1 (88.1±19.0 versus 73.0±15.3 pg/mL; P<0.001) compared with term-born individuals, proportional to elevations in resting and ambulatory blood pressure, as well as degree of prematurity (P<0.05). Maternal hypertensive pregnancy disorder was associated with additional increases in soluble fms-like tyrosine kinase-1 (P=0.002). Other circulating biomarkers, including those of inflammation and endothelial activation, were not related to blood pressure. There was a specific graded association between soluble endoglin and degree of functional and structural capillary rarefaction (P=0.002 and P<0.001), and in multivariable analysis, there were capillary density-mediated associations between soluble endoglin and blood pressure. Preterm-born individuals exhibit an enhanced antiangiogenic state in adult life that is specifically related to elevations in blood pressure. The association seems to be mediated through capillary rarefaction and is independent of other cardiovascular structural and functional differences in the offspring. © 2014 American Heart Association, Inc.

Lack of sex-biased dispersal promotes fine-scale genetic structure in alpine ungulates

Treesearch

Gretchen H. Roffler; Sandra L. Talbot; Gordon Luikart; George K. Sage; Kristy L. Pilgrim; Layne G. Adams; Michael K. Schwartz

2014-01-01

Identifying patterns of fine-scale genetic structure in natural populations can advance understanding of critical ecological processes such as dispersal and gene flow across heterogeneous landscapes. Alpine ungulates generally exhibit high levels of genetic structure due to female philopatry and patchy configuration of mountain habitats. We assessed the spatial scale...

Energy, fine structure, hyperfine structure, and radiative transition rates of the high-lying multi-excited states for B-like neon

NASA Astrophysics Data System (ADS)

Zhang, Chun Mei; Chen, Chao; Sun, Yan; Gou, Bing Cong; Shao, Bin

2015-04-01

The Rayleigh-Ritz variational method with multiconfiguration interaction wave functions is used to obtain the energies of high-lying multi-excited quartet states 1 s 22 s2 pnl and 1 s 22 p 2 nl 4Pe,o ( n ≥ 2) in B-like neon, including the mass polarization and relativistic corrections. The fine structure and hyperfine structure of the excited quartet states for this system are investigated. Configuration structures of the high-lying multi-excited series are further identified by relativistic corrections and fine structure splittings. The transition rates and wavelengths are also calculated. Calculated wavelengths include the quantum electrodynamic effects. The results are compared with other theoretical and experimental data in the literature.

Foaming in simulated radioactive waste.

PubMed

Bindal, S K; Nikolov, A D; Wasan, D T; Lambert, D P; Koopman, D C

2001-10-01

Radioactive waste treatment process usually involves concentration of radionuclides before waste can be immobilized by storing it in stable solid form. Foaming is observed at various stages of waste processing like SRAT (sludge receipt and adjustment tank) and melter operations. This kind of foaming greatly limits the process efficiency. The foam encountered can be characterized as a three-phase foam that incorporates finely divided solids (colloidal particles). The solid particles stabilize foaminess in two ways: by adsorption of biphilic particles at the surfaces of foam lamella and by layering of particles trapped inside the foam lamella. During bubble generation and rise, solid particles organize themselves into a layered structure due to confinement inside the foam lamella, and this structure provides a barrier against the coalescence of the bubbles, thereby causing foaming. Our novel capillary force balance apparatus was used to examine the particle-particle interactions, which affect particle layer formation in the foam lamella. Moreover, foaminess shows a maximum with increasing solid particle concentration. To explain the maximum in foaminess, a study was carried out on the simulated sludge, a non-radioactive simulant of the radioactive waste sludge at SRS, to identify the parameters that affect the foaming in a system characterized by the absence of surface-active agents. This three-phase foam does not show any foam stability unlike surfactant-stabilized foam. The parameters investigated were solid particle concentration, heating flux, and electrolyte concentration. The maximum in foaminess was found to be a net result of two countereffects that arise due to particle-particle interactions: structural stabilization and depletion destabilization. It was found that higher electrolyte concentration causes a reduction in foaminess and leads to a smaller bubble size. Higher heating fluxes lead to greater foaminess due to an increased rate of foam lamella generation in the sludge system.

Precision measurement of the three 2(3)P(J) helium fine structure intervals.

PubMed

Zelevinsky, T; Farkas, D; Gabrielse, G

2005-11-11

The three 2(3)P fine structure intervals of 4H are measured at an improved accuracy that is sufficient to test two-electron QED theory and to determine the fine structure constant alpha to 14 parts in 10(9). The more accurate determination of alpha, to a precision higher than attained with the quantum Hall and Josephson effects, awaits the reconciliation of two inconsistent theoretical calculations now being compared term by term. A low pressure helium discharge presents experimental uncertainties quite different than for earlier measurements and allows direct measurements of light pressure shifts.

Collisional excitation of CH2 rotational/fine-structure levels by helium

NASA Astrophysics Data System (ADS)

Dagdigian, P. J.; Lique, F.

2018-02-01

Accurate determination of the abundance of CH2 in interstellar media relies on both radiative and collisional rate coefficients. We investigate here the rotational/fine-structure excitation of CH2 induced by collisions with He. We employ a recoupling technique to generate fine-structure-resolved cross-sections and rate coefficients from close coupling spin-free scattering calculations. The calculations are based on a recent, high-accuracy CH2-He potential energy surface computed at the coupled clusters level of theory. The collisional cross-section calculations are performed for all fine-structure transitions among the first 22 and 24 energy levels of ortho- and para-CH2, respectively, and for temperatures up to 300 K. As a first application, we simulate the excitation of CH2 in typical molecular clouds. The excitation temperatures of the CH2 lines are found to be small at typical densities of molecular clouds, showing that the non-local thermodynamic equilibrium approach has to be used to analyse interstellar spectra. We also found that the fine-structure lines connected with the 404 - 313 and 505 - 414 rotational transitions show possible maser emissions so that they can be easily seen in emission. These calculations show that CH2 may have to be detected mainly through absorption spectra.

Fine structure in plasma waves and radiation near the plasma frequency in Earth's foreshock

NASA Technical Reports Server (NTRS)

Cairns, Iver H.

1994-01-01

Novel observations are presented of intrunsic fine structure in the frequency spectrum of electomagnetic (EM) radiation and plasma waves near the electron plasma frequency f(sub p) during a period of unusually high interplanetary magnetic field strength. Measured using the wideband receiver on the International Sun-Earth Explorer (ISEE) 1 spacecraft, fine-structured emissions are observed both in the solar wind and the foreshock, The fine structure is shown to correspond to emissions spaced above f(sub p) near half harmonies of the electon cyclotron frequency f(sub ce), i.e., near f(sub p) + nf(sub ce)/2. These appear to be the first space physics observations of emissions spaced by f(sub ce)/2. Indirect but strong arguments are used to discriminate between EM and electrostatic (ES) signals, to identify whether ISEE 1 is in the solar wind or the foreshock, and to determine the relative frequencies of the emissions and the local f(sub p). The data are consistent with generation of the ES and EM emissions in the foreshock, with subsequent propagation of the EM emissions into the solar wind. It remains possible that some emissions currently identified as ES have significant EM character. The ES and EM emisions often merge into one another with minimal changes in frequency, arguing that their source regions and generation mechanisms are related and imposing significant constraints on theories. The f(sub ce)/2 ES and EM fine structures observed may be intrinsic to the emission mechanisms or to superposition of two series of signals with f(sub ce) spacing that differ in starting frequency by f(sub ce)/2. Present theories for nonlinear wave coupling processes, cyclotron maser emission, and other linear instability processes are all unable to explain multiple EM and/or ES components spaced by approximately f(sub ce)/2 above f(sub p) for f(sub p)/f(sub ce) much greater than 1 and typical for shock beams parameters. Suitable avenues for further theoretical research are identified. Empirically, the observed fine structures appear very similar to those in split bnad and multiple-lane type II solar radio bursts; interpretation of both these type II fine structures in terms of f(sub ce)/2 splitting is suggested, thereby supporting and generalizing a suggestion by Wild (1950). A possible application to continuum radiation is mentioned. The ubiquity of these fine structures in the Earth's f(sub p) radiation and foreshock waves remains unknown. Only the ISEE 1 wideband receiver has sufficient frequency resolution (approximately less than or equal to 100 Hz) to perform a dedicated search. Further study of the ubiquity of these fine structures, of how reliably the splitting corresponds to f(sub ce)/2, and of the other interpretations above is necessary.

Internalization of targeted quantum dots by brain capillary endothelial cells in vivo.

PubMed

Paris-Robidas, Sarah; Brouard, Danny; Emond, Vincent; Parent, Martin; Calon, Frédéric

2016-04-01

Receptors located on brain capillary endothelial cells forming the blood-brain barrier are the target of most brain drug delivery approaches. Yet, direct subcellular evidence of vectorized transport of nanoformulations into the brain is lacking. To resolve this question, quantum dots were conjugated to monoclonal antibodies (Ri7) targeting the murine transferrin receptor. Specific transferrin receptor-mediated endocytosis of Ri7-quantum dots was first confirmed in N2A and bEnd5 cells. After intravenous injection in mice, Ri7-quantum dots exhibited a fourfold higher volume of distribution in brain tissues, compared to controls. Immunofluorescence analysis showed that Ri7-quantum dots were sequestered throughout the cerebral vasculature 30 min, 1 h, and 4 h post injection, with a decline of signal intensity after 24 h. Transmission electron microscopic studies confirmed that Ri7-quantum dots were massively internalized by brain capillary endothelial cells, averaging 37 ± 4 Ri7-quantum dots/cell 1 h after injection. Most quantum dots within brain capillary endothelial cells were observed in small vesicles (58%), with a smaller proportion detected in tubular structures or in multivesicular bodies. Parenchymal penetration of Ri7-quantum dots was extremely low and comparable to control IgG. Our results show that systemically administered Ri7-quantum dots complexes undergo extensive endocytosis by brain capillary endothelial cells and open the door for novel therapeutic approaches based on brain endothelial cell drug delivery. © The Author(s) 2015.

Blood Vessel Adaptation with Fluctuations in Capillary Flow Distribution

PubMed Central

Hu, Dan; Cai, David; Rangan, Aaditya V.

2012-01-01

Throughout the life of animals and human beings, blood vessel systems are continuously adapting their structures – the diameter of vessel lumina, the thickness of vessel walls, and the number of micro-vessels – to meet the changing metabolic demand of the tissue. The competition between an ever decreasing tendency of luminal diameters and an increasing stimulus from the wall shear stress plays a key role in the adaptation of luminal diameters. However, it has been shown in previous studies that the adaptation dynamics based only on these two effects is unstable. In this work, we propose a minimal adaptation model of vessel luminal diameters, in which we take into account the effects of metabolic flow regulation in addition to wall shear stresses and the decreasing tendency of luminal diameters. In particular, we study the role, in the adaptation process, of fluctuations in capillary flow distribution which is an important means of metabolic flow regulation. The fluctuation in the flow of a capillary group is idealized as a switch between two states, i.e., an open-state and a close-state. Using this model, we show that the adaptation of blood vessel system driven by wall shear stress can be efficiently stabilized when the open time ratio responds sensitively to capillary flows. As micro-vessel rarefaction is observed in our simulations with a uniformly decreased open time ratio of capillary flows, our results point to a possible origin of micro-vessel rarefaction, which is believed to induce hypertension. PMID:23029014

Morphology Modulation of Direct Inkjet Printing by Incorporating Polymers and Surfactants into a Sol-Gel Ink System.

PubMed

Zhu, Zhennan; Ning, Honglong; Cai, Wei; Wei, Jinglin; Zhou, Shangxiong; Yao, Rihui; Lu, Xubing; Zhang, Jianhua; Zhou, ZhongWei; Peng, Junbiao

2018-06-05

Many methods have been reported to prevent the nonuniformity of inkjet printing structures. Most of them depend on the balance of the capillary flow in the printing pattern during the evaporation of the solvent. However, as the relation of evaporation and capillary flow can obviously vary among different ink systems, it is difficult for a method to fit most of the situations. Therefore, it would be a promising way to eliminate any capillary flow before solvent evaporation so that morphology of the printing structure will not be affected by the evaporation behavior of the ink system. In this paper, a novel method of direct inkjet printing of a uniform metal oxide structure is reported. We introduce a polymer polyacrylamide and a surfactant FSO into a sol-gel ink system, and the new ink system can gel from the printing pattern edge to center as temperature increases because of the cross-linking of the polymer chains. By that means, transport of solute molecules and solvent molecules is limited. Meanwhile, the surfactant can ensure that the solute in the central liquid phase deposits uniformly by enhancing the Marangoni flow during the gelation process. The ZrO 2 film with uniform morphology was fabricated by drying and annealing the gelating film and afforded a leakage current density of 7.48 × 10 -7 A cm -2 at 1 MV and a breakdown field of 1.9 MV cm -1 at an annealing temperature of 250 °C.

High Resolutions Studies of the Structure of the Solar Atmosphere

DTIC Science & Technology

1992-06-30

Pairs in the Solar Wind", submitted to J. Geophys. Res., July 20, 1992. M. Karovska , F. Blundell and S. R. Habbal, "Fine Scale Structure of Active...Regions", manuscript in preparation. M. Karovska , F. Blundell and S. R. Habbal, "Fine Scale Structure of the Solar Limb in a Coronal Hole", manuscript in

Fine-scale genetic structure of whitebark pine (Pinus albicaulis) associations with watershed and growth form

Treesearch

Deborah L. Rogers; Constance I. Millar; Robert D. Westfall

1999-01-01

The fine-scale genetic structure of a subalpine conifer, whitebark pine (Pinus albicaulis Engelm.), was studied at nested geographic levels from watershed to adjacent stems in the eastern Sierra Nevada Range of California. A combination of several characteristics contributed to unpredicted genetic structure in this species. This includes being one of...

Fine- and hyperfine-structure effects in molecular photoionization. I. General theory and direct photoionization.

PubMed

Germann, Matthias; Willitsch, Stefan

2016-07-28

We develop a model for predicting fine- and hyperfine intensities in the direct photoionization of molecules based on the separability of electron and nuclear spin states from vibrational-electronic states. Using spherical tensor algebra, we derive highly symmetrized forms of the squared photoionization dipole matrix elements from which we derive the salient selection and propensity rules for fine- and hyperfine resolved photoionizing transitions. Our theoretical results are validated by the analysis of the fine-structure resolved photoelectron spectrum of O2 reported by Palm and Merkt [Phys. Rev. Lett. 81, 1385 (1998)] and are used for predicting hyperfine populations of molecular ions produced by photoionization.

Wetting, meniscus structure, and capillary interactions of microspheres bound to a cylindrical liquid interface.

PubMed

Kim, Paul Y; Dinsmore, Anthony D; Hoagland, David A; Russell, Thomas P

2018-03-14

Wetting, meniscus structure, and capillary interactions for polystyrene microspheres deposited on constant curvature cylindrical liquid interfaces, constructed from nonvolatile ionic or oligomeric liquids, were studied by optical interferometry and optical microscopy. The liquid interface curvature resulted from the preferential wetting of finite width lines patterned onto planar silicon substrates. Key variables included sphere diameter, nominal (or average) contact angle, and deviatoric interfacial curvature. Menisci adopted the quadrupolar symmetry anticipated by theory, with interfacial deformation closely following predicted dependences on sphere diameter and nominal contact angle. Unexpectedly, the contact angle was not constant locally around the contact line, the nominal contact angle varied among seemingly identical spheres, and the maximum interface deviation did not follow the predicted dependence on deviatoric interfacial curvature. Instead, this deviation was up to an order-of-magnitude larger than predicted. Trajectories of neighboring microspheres visually manifested quadrupole-quadrupole interactions, eventually producing square sphere packings that foreshadow interfacial assembly as a potential route to hierarchical 2D particle structures.

A novel method for the fabrication of microfluidic devices by photopolymerization of polymethylmethacrylate

NASA Astrophysics Data System (ADS)

Forstater, Jacob; Augustine, Brian; Hughes, Chris

2006-11-01

We have developed a new technique for the rapid fabrication of structures useful for microfluidic devices called micromolding by photopolymerization in capillaries (μ-PIC). The technique involves the replication of features from a silicon master in which features on the order of tens to hundreds of microns have been formed by crystallographic etching. The negative of the features is then transferred to a sheet of polymethylmethacrylate (PMMA) by placing the PMMA sheet over the silicon master and injecting a solution of methylmethacrylate monomer with a benzoin methyl ether photoinitiator. This solution is drawn between the PMMA and the silicon by capillary action forming a liquid layer that is no more than a few hundred microns thick. This liquid is then polymerized by exposure to ultraviolet light for less than a half hour. The features transferred in this manner have nearly identical surface structure and roughness. Analysis of these surfaces and structures by atomic force microscopy and scanning electron microscopy will be presented.

Nanoimprinting-induced nanomorphological transition in polymer solar cells: enhanced electrical and optical performance.

PubMed

Jeong, Seonju; Cho, Changsoon; Kang, Hyunbum; Kim, Ki-Hyun; Yuk, Youngji; Park, Jeong Young; Kim, Bumjoon J; Lee, Jung-Yong

2015-03-24

We have investigated the effects of a directly nanopatterned active layer on the electrical and optical properties of inverted polymer solar cells (i-PSCs). The capillary force in confined molds plays a critical role in polymer crystallization and phase separation of the film. The nanoimprinting process induced improved crystallization and multidimensional chain alignment of polymers for more effective charge transfer and a fine phase-separation between polymers and [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) to favor exciton dissociation and increase the generation rate of charge transfer excitons. Consequently, the power conversion efficiency with a periodic nanostructure was enhanced from 7.40% to 8.50% and 7.17% to 9.15% in PTB7 and PTB7-Th based i-PSCs, respectively.

The contribution of visual information to the perception of speech in noise with and without informative temporal fine structure

PubMed Central

Stacey, Paula C.; Kitterick, Pádraig T.; Morris, Saffron D.; Sumner, Christian J.

2017-01-01

Understanding what is said in demanding listening situations is assisted greatly by looking at the face of a talker. Previous studies have observed that normal-hearing listeners can benefit from this visual information when a talker's voice is presented in background noise. These benefits have also been observed in quiet listening conditions in cochlear-implant users, whose device does not convey the informative temporal fine structure cues in speech, and when normal-hearing individuals listen to speech processed to remove these informative temporal fine structure cues. The current study (1) characterised the benefits of visual information when listening in background noise; and (2) used sine-wave vocoding to compare the size of the visual benefit when speech is presented with or without informative temporal fine structure. The accuracy with which normal-hearing individuals reported words in spoken sentences was assessed across three experiments. The availability of visual information and informative temporal fine structure cues was varied within and across the experiments. The results showed that visual benefit was observed using open- and closed-set tests of speech perception. The size of the benefit increased when informative temporal fine structure cues were removed. This finding suggests that visual information may play an important role in the ability of cochlear-implant users to understand speech in many everyday situations. Models of audio-visual integration were able to account for the additional benefit of visual information when speech was degraded and suggested that auditory and visual information was being integrated in a similar way in all conditions. The modelling results were consistent with the notion that audio-visual benefit is derived from the optimal combination of auditory and visual sensory cues. PMID:27085797

A diffusivity model for predicting VOC diffusion in porous building materials based on fractal theory.

PubMed

Liu, Yanfeng; Zhou, Xiaojun; Wang, Dengjia; Song, Cong; Liu, Jiaping

2015-12-15

Most building materials are porous media, and the internal diffusion coefficients of such materials have an important influences on the emission characteristics of volatile organic compounds (VOCs). The pore structure of porous building materials has a significant impact on the diffusion coefficient. However, the complex structural characteristics bring great difficulties to the model development. The existing prediction models of the diffusion coefficient are flawed and need to be improved. Using scanning electron microscope (SEM) observations and mercury intrusion porosimetry (MIP) tests of typical porous building materials, this study developed a new diffusivity model: the multistage series-connection fractal capillary-bundle (MSFC) model. The model considers the variable-diameter capillaries formed by macropores connected in series as the main mass transfer paths, and the diameter distribution of the capillary bundles obeys a fractal power law in the cross section. In addition, the tortuosity of the macrocapillary segments with different diameters is obtained by the fractal theory. Mesopores serve as the connections between the macrocapillary segments rather than as the main mass transfer paths. The theoretical results obtained using the MSFC model yielded a highly accurate prediction of the diffusion coefficients and were in a good agreement with the VOC concentration measurements in the environmental test chamber. Copyright © 2015 Elsevier B.V. All rights reserved.

Fine Structure in Helium-like Fluorine by Fast-Beam Laser Spectroscopy

NASA Astrophysics Data System (ADS)

Myers, E. G.; Thompson, J. K.; Silver, J. D.

1998-05-01

With the aim of providing an additional precise test of higher-order corrections to high precision calculations of fine structure in helium and helium-like ions(T. Zhang, Z.-C. Yan and G.W.F. Drake, Phys. Rev. Lett. 77), 1715 (1996)., a measurement of the 2^3P_2,F - 2^3P_1,F' fine structure in ^19F^7+ is in progress. The method involves doppler-tuned laser spectroscopy using a CO2 laser on a foil-stripped fluorine ion beam. We aim to achieve a higher precision, compared to an earlier measurement(E.G. Myers, P. Kuske, H.J. Andrae, I.A. Armour, H.A. Klein, J.D. Silver, and E. Traebert, Phys. Rev. Lett. 47), 87 (1981)., by using laser beams parallel and anti-parallel to the ion beam, to obtain partial cancellation of the doppler shift(J.K. Thompson, D.J.H. Howie and E.G. Myers, Phys. Rev. A 57), 180 (1998).. A calculation of the hyperfine structure, allowing for relativistic, QED and nuclear size effects, will be required to obtain the ``hyperfine-free'' fine structure interval from the measurements.

Doppler-free spectroscopy of the atomic rubidium fine structure using ultrafast spatial coherent control method

NASA Astrophysics Data System (ADS)

Kim, Minhyuk; Kim, Kyungtae; Lee, Woojun; Kim, Hyosub; Ahn, Jaewook

2017-04-01

Spectral programming solutions for the ultrafast spatial coherent control (USCC) method to resolve the fine-structure energy levels of atomic rubidium are reported. In USCC, a pair of counter-propagating ultrashort laser pulses are programmed to make a two-photon excitation pattern specific to particular transition pathways and atom species, thus allowing the involved transitions resolvable in space simultaneously. With a proper spectral phase and amplitude modulation, USCC has been also demonstrated for the systems with many intermediate energy levels. Pushing the limit of system complexity even further, we show here an experimental demonstration of the rubidium fine-structure excitation pattern resolvable by USCC. The spectral programming solution for the given USCC is achieved by combining a double-V-shape spectral phase function and a set of phase steps, where the former distinguishes the fine structure and the latter prevents resonant transitions. The experimental results will be presented along with its application in conjunction with the Doppler-free frequency-comb spectroscopy for rubidium hyperfine structure measurements. Samsung Science and Technology Foundation [SSTFBA1301-12].

Lung matrix and vascular remodeling in mechanically ventilated elastin haploinsufficient newborn mice

PubMed Central

Hilgendorff, Anne; Parai, Kakoli; Ertsey, Robert; Navarro, Edwin; Jain, Noopur; Carandang, Francis; Peterson, Joanna; Mokres, Lucia; Milla, Carlos; Preuss, Stefanie; Alcazar, Miguel Alejandre; Khan, Suleman; Masumi, Juliet; Ferreira-Tojais, Nancy; Mujahid, Sana; Starcher, Barry; Rabinovitch, Marlene

2014-01-01

Elastin plays a pivotal role in lung development. We therefore queried if elastin haploinsufficient newborn mice (Eln+/−) would exhibit abnormal lung structure and function related to modified extracellular matrix (ECM) composition. Because mechanical ventilation (MV) has been linked to dysregulated elastic fiber formation in the newborn lung, we also asked if elastin haploinsufficiency would accentuate lung growth arrest seen after prolonged MV of neonatal mice. We studied 5-day-old wild-type (Eln+/+) and Eln+/− littermates at baseline and after MV with air for 8–24 h. Lungs of unventilated Eln+/− mice contained ∼50% less elastin and ∼100% more collagen-1 and lysyl oxidase compared with Eln+/+ pups. Eln+/− lungs contained fewer capillaries than Eln+/+ lungs, without discernible differences in alveolar structure. In response to MV, lung tropoelastin and elastase activity increased in Eln+/+ neonates, whereas tropoelastin decreased and elastase activity was unchanged in Eln+/− mice. Fibrillin-1 protein increased in lungs of both groups during MV, more in Eln+/− than in Eln+/+ pups. In both groups, MV caused capillary loss, with larger and fewer alveoli compared with unventilated controls. Respiratory system elastance, which was less in unventilated Eln+/− compared with Eln+/+ mice, was similar in both groups after MV. These results suggest that elastin haploinsufficiency adversely impacts pulmonary angiogenesis and that MV dysregulates elastic fiber integrity, with further loss of lung capillaries, lung growth arrest, and impaired respiratory function in both Eln+/+ and Eln+/− mice. Paucity of lung capillaries in Eln+/− newborns might help explain subsequent development of pulmonary hypertension previously reported in adult Eln+/− mice. PMID:25539853

Uniform Laser Excitation And Detection In Capillary Array Electrophoresis System And Method.

DOEpatents

Li, Qingbo; Zhou, Songsan; Liu, Changsheng

2003-10-07

A capillary electrophoresis system comprises capillaries positioned in parallel to each other forming a plane. The capillaries are configured to allow samples to migrate. A light source is configured to illuminate the capillaries and the samples therein. This causes the samples to emit light. A lens is configured to receive the light emitted by the samples and positioned directly over a first group of the capillaries and obliquely over a second group of the capillaries. The light source is further configured to illuminate the second group of capillaries more than the first group of the capillaries such that amount of light received by the lens from the first group of capillaries is substantially identical to amount of light received from the second group of capillaries when an identical amount of the samples is migrating through the first and second group capillaries.

Capillary electrophoresis electrospray ionization mass spectrometry interface

DOEpatents

Smith, Richard D.; Severs, Joanne C.

1999-01-01

The present invention is an interface between a capillary electrophoresis separation capillary end and an electrospray ionization mass spectrometry emitter capillary end, for transporting an anolyte sample from a capillary electrophoresis separation capillary to a electrospray ionization mass spectrometry emitter capillary. The interface of the present invention has: (a) a charge transfer fitting enclosing both of the capillary electrophoresis capillary end and the electrospray ionization mass spectrometry emitter capillary end; (b) a reservoir containing an electrolyte surrounding the charge transfer fitting; and (c) an electrode immersed into the electrolyte, the electrode closing a capillary electrophoresis circuit and providing charge transfer across the charge transfer fitting while avoiding substantial bulk fluid transfer across the charge transfer fitting. Advantages of the present invention have been demonstrated as effective in providing high sensitivity and efficient analyses.

Designing, producing, and constructing fine-graded hot mix asphalt on Illinois roadways.

DOT National Transportation Integrated Search

2015-04-01

Fine-graded (F-G) asphalt concrete mixtures are composed of an aggregate structure in which the fine fraction controls the : load-carrying capacity of the mix. Other states have reported benefits in using F-G mixtures, including improved compaction, ...

The engineering significance of shrinkage and swelling soils in blast damage investigations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vitton, S.J.; Harris, W.W.

1996-12-01

In the US each year it has been estimated that expansive soils cause approximately $9.0 billion in damage to buildings, roads, airports, and other facilities. This figure alone exceeds the damage estimate for earthquakes, floods, tornadoes, and hurricanes combined. Unfortunately, some cases of expansive soil damage (swelling) are blamed on rock blasting operations if the blasting operations are located within the immediate area. While simple tests, such as the Atterberg limits test, can characterize a soil as expansive, it does not necessarily answer the question whether the foundation soils are causing distresses to a structure. In particular, it appears thatmore » once a soil has been labeled as nonexpansive it is no longer considered as a problem soil, in which case blast vibrations become the prime suspect. It should be emphasized, however, that even non-plastic soils, those soils with low to nonexistent plastic indexes, can exhibit significant shrinkage characteristics that can result in significant damage to structures. While expansive soil is a function of the mineralogy of the soil particles, i.e., swelling clay minerals, shrinkage is caused by the loss of moisture from soil as capillary pressures exceed the cohesion or tensile strength and is therefore a function of the soils particle size and its pore size distribution. This is a significant problem for all fine grained soils regardless of the soil`s mineralogy. It`s particularly important for regions of the US that typically have a positive water balance but experience significant drought periods when soil moisture is lost.« less

Sandy Soil Microaggregates: Rethinking Our Understanding of Hydraulic Function

DOE Office of Scientific and Technical Information (OSTI.GOV)

Paradiś, Ashley; Brueck, Christopher; Meisenheimer, Douglas

2017-01-01

This study investigated the peculiar structure of microaggregates in coarse sandy soils that exhibit only external porosity and investigated their control on soil hydrology. The microstructure underpins a hydrologic existence that differs from finer textured soils where aggregates have internal porosity. Understanding the impact of these microaggregates on soil hydrology will permit improved agricultural irrigation management and estimates associated with ecosystem capacity and resiliency. Microstructure was investigated using a digital microscope, and aspects of the structure were quantified by sedimentation and computed microtomography. Sandy soil microaggregates were observed to be comprised of a solid sand-grain core that is coated withmore » fines, presumably cemented by organic media. This microstructure leads to three distinct water pools during drainage: capillary water, followed by thick films (1–20 μm) enveloping the outer surfaces of the crusted microaggregates, followed by adsorbed thin films (<1 μm). The characteristics of the thick films were investigated using an analytical model. These films may provide as much as 10 to 40% saturation in the range of plant-available water. Using lubrication theory, it was predicted that thick film drainage follows a power law function with an exponent of 2. Thick films may also have a role in the geochemical evolution of soils and in ecosystem function because they provide contiguous water and gas phases at relatively high moisture contents. And, because the rough outer crust of these microaggregates can provide good niches for microbial activity, biofilm physics will dominate thick film processes, and consequently hydrologic, biologic, and geochemical functions for coarse sandy soils.« less

‘Chip-olate’ and dry-film resists for efficient fabrication, singulation and sealing of microfluidic chips

NASA Astrophysics Data System (ADS)

Temiz, Yuksel; Delamarche, Emmanuel

2014-09-01

This paper describes a technique for high-throughput fabrication and efficient singulation of chips having closed microfluidic structures and takes advantage of dry-film resists (DFRs) for efficient sealing of capillary systems. The technique is illustrated using 4-inch Si/SiO2 wafers. Wafers carrying open microfluidic structures are partially diced to about half of their thickness. Treatments such as surface cleaning are done at wafer-level, then the structures are sealed using low-temperature (45 °C) lamination of a DFR that is pre-patterned using a craft cutter, and ready-to-use chips are finally separated manually like a chocolate bar by applying a small force (≤ 4 N). We further show that some DFRs have low auto-fluorescence at wavelengths typically used for common fluorescent dyes and that mechanical properties of some DFRs allow for the lamination of 200 μm wide microfluidic structures with negligible sagging (~1 μm). The hydrophilicity (advancing contact angle of ~60°) of the DFR supports autonomous capillary-driven flow without the need for additional surface treatment of the microfluidic chips. Flow rates from 1 to 5 µL min-1 are generated using different geometries of channels and capillary pumps. In addition, the ‘chip-olate’ technique is compatible with the patterning of capture antibodies on DFR for use in immunoassays. We believe this technique to be applicable to the fabrication of a wide range of microfluidic and lab-on-a-chip devices and to offer a viable alternative to many labor-intensive processes that are currently based on wafer bonding techniques or on the molding of poly(dimethylsiloxane) (PDMS) layers.

Applications of x ray absorption fine structure to the in situ study of the effect of cobalt in nickel hydrous oxide electrodes for fuel cells and rechargeable batteries

NASA Technical Reports Server (NTRS)

Kim, Sunghyun; Tryk, Donald A.; Scherson, Daniel A.; Antonio, Mark R.

1993-01-01

Electronic and structural aspects of composite nickel-cobalt hydrous oxides have been examined in alkaline solutions using in situ X-ray absorption fine structure (XAFS). The results obtained have indicated that cobalt in this material is present as cobaltic ions regardless of the oxidation state of nickel in the lattice. Furthermore, careful analysis of the Co K-edge Extended X-ray absorption fine structure data reveals that the co-electrodeposition procedure generates a single phase, mixed metal hydrous oxide, in which cobaltic ions occupy nickel sites in the NiO2 sheet-like layers and not two intermixed phases each consisting of a single metal hydrous oxide.

Variations in the fine-structure constant constraining gravity theories

NASA Astrophysics Data System (ADS)

Bezerra, V. B.; Cunha, M. S.; Muniz, C. R.; Tahim, M. O.; Vieira, H. S.

2016-08-01

In this paper, we investigate how the fine-structure constant, α, locally varies in the presence of a static and spherically symmetric gravitational source. The procedure consists in calculating the solution and the energy eigenvalues of a massive scalar field around that source, considering the weak-field regime. From this result, we obtain expressions for a spatially variable fine-structure constant by considering suitable modifications in the involved parameters admitting some scenarios of semi-classical and quantum gravities. Constraints on free parameters of the approached theories are calculated from astrophysical observations of the emission spectra of a white dwarf. Such constraints are finally compared with those obtained in the literature.

Impacts of Natural Surfactant Soybean Phospholipid on Wettability of High-rank Coal Reservoir

NASA Astrophysics Data System (ADS)

Lyu, S.; Xiao, Y.; Yuan, M.; Wang, S.

2017-12-01

It is significant to change the surface wettability of coal rock with the surfactant in coal mining and coalbed methane exploitation. Soybean phospholipid (SP) is a kind of natural zwitterionic surfactant which is non-toxic and degradable. In order to study the effects of soybean phospholipid on wettability of high-rank coal in Qinshui Basin, some experiments including surface tension test, contact angle measurement on the coal surface, coal fines imbibition, observation of dispersion effect and gas permeability test were carried out, and water locking mechanism of fracturing fluid in micro fractures of coal reservoir was analyzed. The results show that the surface of high-rank coal was negatively charged in solution and of weak hydrophilicity. The soybean phospholipid with the mass fraction of 0.1% reduced the surface tension of water by 69%, and increased the wettability of coal. Meanwhile, the soybean phospholipid helped coal fines to disperse by observation of the filter cake with the scanning electron microscope. The rising rate of soybean phospholipid solution in the pipe filled with coal fines was lower than that of anionic and cationic surfactant, higher than that of clean water and non-ionic surfactant. Composite surfactant made up of soybean phospholipid and OP-10 at the ratio of 1:3 having a low surface tension and large contact angle, reduced the capillary force effectively, which could be conducive to discharge of fracturing fluid from coal reservoir micro fracture and improve the migration channels of gas. Therefore it has a broad application prospect.

Fine Structure of Diffuse Scattering Rings in Al-Li-Cu Quasicrystal: A Comparative X-ray and Electron Diffraction Study

NASA Astrophysics Data System (ADS)

Donnadieu, P.; Dénoyer, F.

1996-11-01

A comparative X-ray and electron diffraction study has been performed on Al-Li-Cu icosahedral quasicrystal in order to investigate the diffuse scattering rings revealed by a previous work. Electron diffraction confirms the existence of rings but shows that the rings have a fine structure. The diffuse aspect on the X-ray diffraction patterns is then due to an averaging effect. Recent simulations based on the model of canonical cells related to the icosahedral packing give diffractions patterns in agreement with this fine structure effect. Nous comparons les diagrammes de diffraction des rayon-X et des électrons obtenus sur les mêmes échantillons du quasicristal icosaèdrique Al-Li-Cu. Notre but est d'étudier les anneaux de diffusion diffuse mis en évidence par un travail précédent. Les diagrammes de diffraction électronique confirment la présence des anneaux mais ils montrent aussi que ces anneaux possèdent une structure fine. L'aspect diffus des anneaux révélés par la diffraction des rayons X est dû à un effet de moyenne. Des simulations récentes basées sur la décomposition en cellules canoniques de l'empilement icosaédrique produisent des diagrammes de diffraction en accord avec ces effects de structure fine.

Local Fine Structural Insight into Mechanism of Electrochemical Passivation of Titanium.

PubMed

Wang, Lu; Yu, Hongying; Wang, Ke; Xu, Haisong; Wang, Shaoyang; Sun, Dongbai

2016-07-20

Electrochemically formed passive film on titanium in 1.0 M H2SO4 solution and its thickness, composition, chemical state, and local fine structure are examined by Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS), and X-ray absorption fine structure. AES analysis reveals that the thickness and composition of oxide film are proportional to the reciprocal of current density in potentiodynamic polarization. XPS depth profiles of the chemical states of titanium exhibit the coexistence of various valences cations in the surface. Quantitative X-ray absorption near edge structure analysis of the local electronic structure of the topmost surface (∼5.0 nm) shows that the ratio of [TiO2]/[Ti2O3] is consistent with that of passivation/dissolution of electrochemical activity. Theoretical calculation and analysis of extended X-ray absorption fine structure spectra at Ti K-edge indicate that both the structures of passivation and dissolution are distorted caused by the appearance of two different sites of Ti-O and Ti-Ti. And the bound water in the topmost surface plays a vital role in structural disorder confirmed by XPS. Overall, the increase of average Ti-O coordination causes the electrochemical passivation, and the dissolution is due to the decrease of average Ti-Ti coordination. The structural variations of passivation in coordination number and interatomic distance are in good agreement with the prediction of point defect model.

Fine- and hyperfine-structure effects in molecular photoionization. I. General theory and direct photoionization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Germann, Matthias; Willitsch, Stefan, E-mail: stefan.willitsch@unibas.ch

2016-07-28

We develop a model for predicting fine- and hyperfine intensities in the direct photoionization of molecules based on the separability of electron and nuclear spin states from vibrational-electronic states. Using spherical tensor algebra, we derive highly symmetrized forms of the squared photoionization dipole matrix elements from which we derive the salient selection and propensity rules for fine- and hyperfine resolved photoionizing transitions. Our theoretical results are validated by the analysis of the fine-structure resolved photoelectron spectrum of O{sub 2} reported by Palm and Merkt [Phys. Rev. Lett. 81, 1385 (1998)] and are used for predicting hyperfine populations of molecular ionsmore » produced by photoionization.« less

Congenital capillary proliferation of the kidney: a distinctive renal vascular lesion of childhood.

PubMed

Cajaiba, Mariana M; North, Paula E; Gong, Shunyou; Dickman, Paul S; Mroczek-Musulman, Elizabeth; Sauer, David A; Perlman, Elizabeth J

2017-08-01

Renal vascular lesions (RVL) are rare, and their morphological spectrum remains largely unknown, particularly in children. In this study, we characterize the clinicopathological features of RVL in a cohort of 12 children. Seven lesions were classified as previously recognized entities: vascular malformations (4), papillary endothelial hyperplasia (2), and pyogenic granuloma (lobular capillary hemangioma; 1). An eighth lesion showed nonspecific findings, which were interpreted as reactive during our review. The remaining 4 cases presented either prenatally, at birth, or shortly after birth and were morphologically similar. These were characterized by a peculiar pattern of capillary proliferation with entrapment of native renal structures, variable amounts of extramedullary hematopoiesis and reactive lymphocytes, foci of infarction and hemorrhage, and the presence of feeding and draining vessels at their periphery. To our knowledge, this represents a previously undescribed congenital vascular lesion involving the kidney, which we have descriptively and provisionally termed congenital capillary proliferation of the kidney (CCPK). While it is unclear whether CCPK represents a malformation or neoplastic proliferation, it shows overlapping features with congenital hemangioma of the liver (solitary congenital hepatic hemangioma) and congenital nonprogressive hemangioma (CNH) of the skin and soft tissue, suggesting a possible common pathogenesis among these 3 entities. Copyright © 2017 Elsevier Inc. All rights reserved.

Microcrystallography using single-bounce monocapillary optics

PubMed Central

Gillilan, R. E.; Cook, M. J.; Cornaby, S. W.; Bilderback, D. H.

2010-01-01

X-ray microbeams have become increasingly valuable in protein crystallography. A number of synchrotron beamlines worldwide have adapted to handling smaller and more challenging samples by providing a combination of high-precision sample-positioning hardware, special visible-light optics for sample visualization, and small-diameter X-ray beams with low background scatter. Most commonly, X-ray microbeams with diameters ranging from 50 µm to 1 µm are produced by Kirkpatrick and Baez mirrors in combination with defining apertures and scatter guards. A simple alternative based on single-bounce glass monocapillary X-ray optics is presented. The basic capillary design considerations are discussed and a practical and robust implementation that capitalizes on existing beamline hardware is presented. A design for mounting the capillary is presented which eliminates parasitic scattering and reduces deformations of the optic to a degree suitable for use on next-generation X-ray sources. Comparison of diffraction data statistics for microcrystals using microbeam and conventional aperture-collimated beam shows that capillary-focused beam can deliver significant improvement. Statistics also confirm that the annular beam profile produced by the capillary optic does not impact data quality in an observable way. Examples are given of new structures recently solved using this technology. Single-bounce monocapillary optics can offer an attractive alternative for retrofitting existing beamlines for microcrystallography. PMID:20157276

Wall slipping behavior of foam with nanoparticle-armored bubbles and its flow resistance factor in cracks.

PubMed

Lv, Qichao; Li, Zhaomin; Li, Binfei; Husein, Maen; Shi, Dashan; Zhang, Chao; Zhou, Tongke

2017-07-11

In this work, wall slipping behavior of foam with nanoparticle-armored bubbles was first studied in a capillary tube and the novel multiphase foam was characterized by a slipping law. A crack model with a cuboid geometry was then used to compare with the foam slipping results from the capillary tube and also to evaluate the flow resistance factor of the foam. The results showed that the slipping friction force F FR in the capillary tube significantly increased by addition of modified SiO 2 nanoparticles, and an appropriate power law exponents by fitting F FR vs. Capillary number, Ca, was 1/2. The modified nanoparticles at the surface were bridged together and formed a dense particle "armor" surrounding the bubble, and the interconnected structures of the "armor" with strong steric integrity made the surface solid-like, which was in agreement with the slip regime associated with rigid surface. Moreover, as confirmed by 3D microscopy, the roughness of the bubble surface increased with nanoparticle concentration, which in turn increased the slipping friction force. Compared with pure SDBS foam, SDBS/SiO 2 foam shows excellent stability and high flow resistance in visual crack. The resistance factor of SiO 2 /SDBS foam increased as the wall surface roughness increased in core cracks.

Abnormal mural cell recruitment in lymphatic capillaries: a common pathological feature in chronic lymphedematous skin?

PubMed

Yu, Zi-You; Sun, Di; Luo, Yi; Liu, Ning-Fei

2016-10-01

This study aimed to explore the structural and functional characteristics of dermal lymphatic capillaries in patients with chronic LE, specifically focused on the mural cells that are associated with skin lymphatics. Forty-four patients (30 primary LE and 14 secondary LE) and eight healthy controls were enrolled in this study. Genetic analysis of the FOXC2 was performed in 18 patients with primary LE. Full-thickness skin was excised and immunohistologically stained for podoplanin and α-SMA. The proportions of α-SMA + Lv (α-SMA + Lv%) were calculated. Lymphatic vascular function was assessed by indocyanine green lymphography. Analysis of FOXC2 revealed two mutations in two patients with LDs. Histologically, thirty-nine patients exhibited increased α-SMA + mural cell coverage of lymphatic capillaries. The α-SMA + Lv% values in the superficial and deep dermis in patients with primary and secondary LE were significantly higher than in the control group. Compared with imaging findings in healthy limbs, in which the collecting lymphatics were clearly visualized, lymphedematous extremities all exhibited dermal backflow. Abnormal recruitment of mural cells in dermal lymphatic capillaries is a common pathological event in chronic LE, and may play a role in disease evolution. © 2016 John Wiley & Sons Ltd.

Mechanism of molecular recognition on molecular imprinted monolith by capillary electrochromatography.

PubMed

Liu, Zhao-Sheng; Xu, Yan-Li; Yan, Chao; Gao, Ru-Yu

2005-09-16

The recognition mechanism of molecularly imprinted polymer (MIP) in capillary electrochromatography (CEC) is complicated since it possesses a hybrid process, which comprises the features of chromatographic retention, electrophoretic migration and molecular imprinting. For an understanding of the molecular recognition of MIP in CEC, a monolithic MIP in a capillary with 1,1'-binaphthyl-2,2'-diamine (BNA) imprinting was prepared by in situ copolymerization of imprinted molecule, methacrylic acid and ethylene glycol dimethacrylate in porogenic solvent, a mixture of toluene-isooctane. Strong recognition ability and high column performance (theory plates was 43,000 plates/m) of BNA were achieved on this monolithic MIP in CEC mode. In addition, BNA and its structural analogue, 1,1'-bi-2, 2'-naphthol, differing in functional groups, were used as model compounds to study imprinting effect on the resultant BNA-imprinted monolithic column, a reference column without imprinting of BNA and a open capillary. The effects of organic modifier concentration, pH value of buffer, salt concentration of buffer and column temperature on the retention and recognition of two compounds were investigated. The results showed that the molecular recognition on MIP monolith in CEC mode mainly derived from imprinting cavities on BNA-imprinted polymer other than chromatographic retention and electrophoretic migration.

Effects of unsaturated zone on ground-water mounding

USGS Publications Warehouse

Sumner, D.M.; Rolston, D.E.; Marino, M.A.

1999-01-01

The design of infiltration basins used to dispose of treated wastewater or for aquifer recharge often requires estimation of ground-water mounding beneath the basin. However, the effect that the unsaturated zone has on water-table response to basin infiltration often has been overlooked in this estimation. A comparison was made between two methods used to estimate ground-water mounding-an analytical approach that is limited to the saturated zone and a numerical approach that incorporates both the saturated and the unsaturated zones. Results indicate that the error that is introduced by a method that ignores the effects of the unsaturated zone on ground-water mounding increases as the basin-loading period is shortened; as the depth to the water table increases, with increasing subsurface anisotropy; and with the inclusion of fine-textured strata. Additionally, such a method cannot accommodate the dynamic nature of basin infiltration, the finite transmission time of the infiltration front to the water table, or the interception of the basin floor by the capillary fringe.The design of infiltration basins used to dispose of treated wastewater or for aquifer recharge often requires estimation of ground-water mounding beneath the basin. However, the effect that the unsaturated zone has on water-table response to basin infiltration often has been overlooked in this estimation. A comparison was made between two methods used to estimate ground-water mounding - an analytical approach that is limited to the saturated zone and a numerical approach that incorporates both the saturated and the unsaturated zones. Results indicate that the error that is introduced by a method that ignores the effects of the unsaturated zone on ground-water mounding increases as the basin-loading period is shortened; as the depth to the water table increases, with increasing subsurface anisotropy; and with the inclusion of fine-textured strata. Additionally, such a method cannot accommodate the dynamic nature of basin infiltration, the finite transmission time of the infiltration front to the water, or the interception of the basin floor by the capillary fringe.

Liquid metal porous matrix sliding electrical contact: A concept

NASA Technical Reports Server (NTRS)

Ferguson, H.

1973-01-01

Concept utilizes porous metal or nonmetal matrix containing liquid metal in porous structure and confines liquid metal to contact area between rotor and brush by capillary forces. System may also be used to lubricate bearing systems.

Non-contact printing of optical waveguides using capillary bridges.

PubMed

Theiler, Pius M; Lütolf, Fabian; Ferrini, Rolando

2018-04-30

Non-contact printing methods such as inkjet, electro hydrodynamic, and aerosol printing have attracted attention for their precise deposition of functional materials that are needed in printed electronics, optoelectronics, photonics, biotechnology, and microfluidics. In this article, we demonstrate printing of tapered optical waveguides with losses of 0.61 ± 0.26 dB/cm, with the best performing structure achieving 0.19 dB/cm. Such continuous features are indispensable for successfully printing functional patterns, but they are often corrupted by capillary forces. The proposed inkjet printing method uses these forces to align liquid bridges into continuous features, enabling the printing of smooth lines on substrates with arbitrary contact angles.

Polar stationary phases based on poly(oligo ethylene glycol)diacrylates for capillary gas chromatography

NASA Astrophysics Data System (ADS)

Shiryaeva, V. E.; Popova, T. P.; Korolev, A. A.; Kanat'eva, A. Yu.; Kurganov, A. A.

2017-08-01

New stationary phases for capillary columns in GC are synthesized and studied. The phases are prepared by depositing oligo(ethylene glycol)diacrylates on the column walls and subsequent polymerization (crosslinking) in the presence of peroxide initiators. It is shown that stationary phases based on monomers with molecular weights of 10 kDa or higher exhibit separation properties similar to those of conventional stationary phases based on polyethylene glycol (PEG); however, their thermal stability is higher because they have a higher degree of crosslinking and a more ordered structure of the crosslinked polymers than the respective parameters of phases based on native PEG.

Multi-leg heat pipe evaporator

NASA Technical Reports Server (NTRS)

Alario, J. P.; Haslett, R. A. (Inventor)

1986-01-01

A multileg heat pipe evaporator facilitates the use and application of a monogroove heat pipe by providing an evaporation section which is compact in area and structurally more compatible with certain heat exchangers or heat input apparatus. The evaporation section of a monogroove heat pipe is formed by a series of parallel legs having a liquid and a vapor channel and a communicating capillary slot therebetween. The liquid and vapor channels and interconnecting capillary slots of the evaporating section are connected to the condensing section of the heat pipe by a manifold connecting liquid and vapor channels of the parallel evaporation section legs with the corresponding liquid and vapor channels of the condensing section.

Analytical Glycobiology at High Sensitivity: Current Approaches and Directions

PubMed Central

Novotny, Milos V.; Alley, William R.; Mann, Benjamin F.

2013-01-01

This review summarizes the analytical advances made during the last several years in the structural and quantitative determinations of glycoproteins in complex biological mixtures. The main analytical techniques used in the fields of glycomics and glycoproteomics involve different modes of mass spectrometry and their combinations with capillary separation methods such as microcolumn liquid chromatography and capillary electrophoresis. The needs for high-sensitivity measurements have been emphasized in the oligosaccharide profiling used in the field of biomarker discovery through MALDI mass spectrometry. High-sensitivity profiling of both glycans and glycopeptides from biological fluids and tissue extracts has been aided significantly through lectin preconcentration and the uses of affinity chromatography. PMID:22945852

a Measurement of the Fine Structure Constant

NASA Astrophysics Data System (ADS)

Hensley, Joel M.; Wicht, Andreas; Sarajlic, Edina; Chu, Steven

2002-06-01

Using an atom interferometer method, we measure the recoil velocity of cesium due to the coherent scattering of a photon. This measurement is used to obtain a preliminary value of ħ/MCs and the fine structure constant, α, with an uncertainty Δα/α = 7.3 × 10-9.

Condensing Heat Exchanger with Hydrophilic Antimicrobial Coating

NASA Technical Reports Server (NTRS)

Thomas, Christopher M. (Inventor); Ma, Yonghui (Inventor)

2014-01-01

A multi-layer antimicrobial hydrophilic coating is applied to a substrate of anodized aluminum, although other materials may form the substrate. A silver layer is sputtered onto a thoroughly clean anodized surface of the aluminum to about 400 nm thickness. A layer of crosslinked, silicon-based macromolecular structure about 10 nm thickness overlies the silver layer, and the outermost surface of the layer of crosslinked, silicon-based macromolecular structure is hydroxide terminated to produce a hydrophilic surface with a water drop contact angle of less than 10.degree.. The coated substrate may be one of multiple fins in a condensing heat exchanger for use in the microgravity of space, which has narrow channels defined between angled fins such that the surface tension of condensed water moves water by capillary flow to a central location where it is pumped to storage. The antimicrobial coating prevents obstruction of the capillary passages.

Direct chemical-analysis of uv laser-ablation products of organic polymers by using selective ion monitoring mode in gas-chromatography mass-spectrometry

USGS Publications Warehouse

Cho, Yirang; Lee, H.W.; Fountain, S.T.; Lubman, D.M.

1994-01-01

Trace quantities of laser ablated organic polymers were analyzed by using commercial capillary column gas chromatography/mass spectrometry; the instrument was modified so that the laser ablation products could be introduced into the capillary column directly and the constituents of each peak in the chromatogram were identified by using a mass spectrometer. The present study takes advantage of the selective ion monitoring mode for significantly improving the sensitivity of the mass spectrometer as a detector, which is critical in analyzing the trace quantities and confirming the presence or absence of the species of interest in laser ablated polymers. The initial composition of the laser ablated polymers was obtained by using an electron impact reflectron time-of-flight mass spectrometer and the possible structure of the fragments observed in the spectra was proposed based on the structure of the polymers.

Self-Structuring of Granular material under Capillary Bulldozing

NASA Astrophysics Data System (ADS)

Dumazer, Guillaume; Sandnes, Bjørnar; Ayaz, Monem; Måløy, Knut Jørgen; Flekkøy, Eirik

2017-06-01

An experimental observation of the structuring of a granular suspension under the progress of a gas/liquid meniscus in a narrow tube is reported here. The granular material is moved and compactifies as a growing accumulation front. The frictional interaction with the confining walls increases until the pore capillary entry pressure is reached. The gas then penetrates the clogged granular packing and a further accumulation front is formed at the far side of the plug. This cyclic process continues until the gas/liquid interface reaches the tube's outlet, leaving a trail of plugs in the tube. Such 1D pattern formation belongs to a larger family of patterning dynamics observed in 2D Hele-Shaw geometry. The cylindrical geometry considered here provides an ideal case for a theoretical modelling for forced granular matter oscillating between a long frictional phase and a sudden viscous fluidization.

Self organized spatio-temporal structure within the fractured Vadose Zone: The influence of dynamic overloading at fracture intersections

NASA Astrophysics Data System (ADS)

LaViolette, Randall A.; Glass, Robert J.

2004-09-01

Under low flow conditions (where gravity and capillary forces dominate) within an unsaturated fracture network, fracture intersections act as capillary barriers to integrate flow from above and then release it as a pulse below. Water exiting a fracture intersection is often thought to enter the single connected fracture with the lowest invasion pressure. When the accumulated volume varies between intersections, the smaller volume intersections can be overloaded to cause all of the available fractures exiting an intersection to flow. We included the dynamic overloading process at fracture intersections within our previously discussed model where intersections were modeled as tipping buckets connected within a two-dimensional diamond lattice. With dynamic overloading, the flow behavior transitioned smoothly from diverging to converging flow with increasing overload parameter, as a consequence of a heterogeneous field, and they impose a dynamic structure where additional pathways activate or deactivate in time.

Water transport mechanism through open capillaries analyzed by direct surface modifications on biological surfaces

NASA Astrophysics Data System (ADS)

Ishii, Daisuke; Horiguchi, Hiroko; Hirai, Yuji; Yabu, Hiroshi; Matsuo, Yasutaka; Ijiro, Kuniharu; Tsujii, Kaoru; Shimozawa, Tateo; Hariyama, Takahiko; Shimomura, Masatsugu

2013-10-01

Some small animals only use water transport mechanisms passively driven by surface energies. However, little is known about passive water transport mechanisms because it is difficult to measure the wettability of microstructures in small areas and determine the chemistry of biological surfaces. Herein, we developed to directly analyse the structural effects of wettability of chemically modified biological surfaces by using a nanoliter volume water droplet and a hi-speed video system. The wharf roach Ligia exotica transports water only by using open capillaries in its legs containing hair- and paddle-like microstructures. The structural effects of legs chemically modified with a self-assembled monolayer were analysed, so that the wharf roach has a smart water transport system passively driven by differences of wettability between the microstructures. We anticipate that this passive water transport mechanism may inspire novel biomimetic fluid manipulations with or without a gravitational field.

Discriminative staining methods for the nervous system: luxol fast blue--periodic acid-Schiff--hematoxylin triple stain and subsidiary staining methods.

PubMed

Goto, N

1987-09-01

This paper describes a new series of staining methods which can discriminatively demonstrate every structure of the nervous system, including axons and capillaries, in animal and human materials. Methods described in this paper consist of one primary stain, luxol fast blue-periodic acid Schiff-hematoxylin (LPH) and six different subsidiary staining methods. The LPH triple stain can precisely differentiate the following structures: neurons (Nissl bodies, cytoplasm, nuclear membrane and nucleolus), various kinds of nuclei (glia, ependyma, endothelium, leucocyte, connective tissue, etc.), myelin sheaths, neuronal processes (axons and dendrites), reacted glial cell bodies (protoplasmic astrocytes, foamy cells, etc.), blood vessels (arteries, veins and capillaries), meninges, intervening connective tissue, erythrocytes, lipofuscin granules, amyloid bodies, and others. Subsidiary staining methods are also described briefly. Applications are discussed in the context of staining technology and neuromorphological research.

A compact and low-cost laser induced fluorescence detector with silicon based photodetector assembly for capillary flow systems.

PubMed

Geng, Xuhui; Shi, Meng; Ning, Haijing; Feng, Chunbo; Guan, Yafeng

2018-05-15

A compact and low-cost laser induced fluorescence (LIF) detector based on confocal structure for capillary flow systems was developed and applied for analysis of Her2 protein on single Hela cells. A low-power and low-cost 450 nm laser diode (LD) instead of a high quality laser was used as excitation light source. A compact optical design together with shortened optical path length improved the optical efficiency and detection sensitivity. A superior silicon based photodetector assembly was used for fluorescence detection instead of a photomultiplier (PMT). The limit of detection (LOD) for fluorescein sodium was 3 × 10 -12 M or 165 fluorescein molecules in detection volume measured on a homemade capillary electroosmotic driven (EOD)-LIF system, which was similar to commercial LIFs. Compared to commercial LIFs, the whole volume of our LIF was reduced to 1/2-1/3, and the cost was less than 1/3 of them. Copyright © 2018 Elsevier B.V. All rights reserved.

Radial fingering under arbitrary viscosity and density ratios

NASA Astrophysics Data System (ADS)

Anjos, Pedro H. A.; Dias, Eduardo O.; Miranda, José A.

2017-08-01

We study viscous fingering formation in radial Hele-Shaw cell geometry considering the combined action of capillary and inertial effects for arbitrary values of viscosity and density ratios. We tackle the problem by employing a perturbative mode-coupling approach and focus our attention on weakly nonlinear stages of the dynamics. If inertial effects are neglected, our theoretical results indicate that the shape of the resulting interfacial patterns is significantly affected by changes in the viscosity ratio. Under such conditions, the growing fingers tend to proliferate through a repeated ramification process (e.g., by finger bifurcation, quadrifurcation, etc.) as the capillary number is increased. Nevertheless, we find that this scenario is dramatically altered when inertia is taken into account. When inertia is relevant, the conventional finger splitting morphologies are replaced by three-lobed structures, characterized by the occurrence of sidebranching phenomena. We verify that slightly different types of sidebranched patterns arise, presenting either wide or sharp fingertips, for a range of capillary numbers and density ratios.

Capillary evaporation of the ionic liquid [EMIM][BF4] in nanoscale solvophobic confinement

NASA Astrophysics Data System (ADS)

Shrivastav, Gourav; Remsing, Richard C.; Kashyap, Hemant K.

2018-05-01

Solvent density fluctuations play a crucial role in liquid-vapor transitions in solvophobic confinement and can also be important for understanding solvation of polar and apolar solutes. In the case of ionic liquids (ILs), density fluctuations can be used to understand important processes in the context of nanoscale aggregation and colloidal self-assemblies. In this article, we explore the nature of density fluctuations associated with capillary evaporation of the IL 1-ethyl-3-methylimidazolium tetrafluoroborate ([EMIM][BF4]) in the confined region of model solvophobic nanoscale sheets by using molecular dynamics simulations combined with non-Boltzmann sampling techniques. We demonstrate that density fluctuations of the confined IL play an important role in capillary evaporation, suggesting analogies to dewetting transitions involving water. Significant changes in the interfacial structure of the IL are also detailed and suggested to underlie a non-classical (non-parabolic) dependence of the free energy barrier to evaporation on the degree of confinement.

Drainage Behavior in Soap Films Above and Below the CMC

NASA Astrophysics Data System (ADS)

Berg, S.; Adelizzi, E. A.; Troian, S. M.

2003-11-01

We investigate through laser interferometry the drainage behavior of Newtonian soap films initially entrained on a fiber frame at small and constant capillary number. The initial film thickness is sufficiently small that gravitational drainage is presumed minimal. The drainage of rigid soap films by capillary forces alone should proceed according to h(t) ˜ t^- 1/2. Our experimental results show much more rapid drainage with exponents as large as -2, especially for those solutions whose surfactant concentrations are below the CMC. Video recordings of the entire film surface reveal a variety of structures during the drainage process, some attributable to marginal regeneration. Though still a controversial issue, this regeneration process is believed to be caused by surfactant accumulation in the meniscus region (1). We show that modification of the relevant capillary drainage equation to account for Marangoni effects through a course-grained slip condition at the air-liquid interface produces exponents in better agreement with experimental findings. (1) V. A. Nierstrasz and G. Frens, JCIS 215, 28 (1999).

[Blood vessels of the epiphysis in comparative-anatomical aspect].

PubMed

Selin, Iu M

1977-05-01

The structure of the epiphysis and its inner blood vessels were studied in the representatives of nine orders of placental mammals and in man by means of injection of stained masses into the arteries and veins and subsequent preparation of histological sections. Not only form and topography of the organ differ in the representatives of different orders, but histological picture of the epiphysis is specific for each of them. In insectivores and chiroptera the loops of the inner three-dimensional capillary network are stretched along the longitudinal axis of the organ. In the epiphysis of carnivores, ungulata and monkey, the intraorganic vessels are situated in stromal trabeculae and the loops of the capillary network have polygonal shape. The intraepiphyseal vessels in man are arranged in peculiar baskets which envelope parenchymal lobules. The intraorganic veins beginning from the loops of the capillary network do not follow the arteries penetrating into the organ, but independently go to different surface parts of the organ where they flow into extraorganic veins.

Self-assembly of thin, triangular prisms into open networks at a flat air-water interface

NASA Astrophysics Data System (ADS)

Solomon, Michael; Ferrar, Joseph; Bedi, Deshpreet; Zhou, Shangnan; Mao, Xiaoming

We observe capillary-driven binding between thin, equilateral triangle microprisms at a flat air-water interface. The triangles are fabricated from epoxy resin via SU-8 photolithography. For small thickness to length (T/L) ratios, two distinct pairwise particle-particle binding events occur with roughly equal frequency, and optical and environmental scanning electron microscopy (eSEM) demonstrate that these two distinct binding events are driven by the specific manner in which the interface is pinned to the particle surface. Additionally, particle bending is observed for the lowest T/L ratios, which leads to enhanced interface curvature and thus enhanced strength of capillary-driven attractions, and may also play a pivotal role in the dichotomy in particle-particle binding. Dichotomy in particle-particle binding is not observed at thicker T/L ratios, although capillary-driven binding still occurs. Ultimately, the particles self-assemble into space-spanning open networks, and the results suggest design parameters for the fabrication of building blocks of ordered open structures, such as the Kagome lattice.

Non-aqueous capillary electrophoretic separation of cholesterol and 25-hydroxycholesterol after derivatization with Girard P reagent.

PubMed

Gregus, Michal; Roberg-Larsen, Hanne; Lundanes, Elsa; Foret, Frantisek; Kuban, Petr; Wilson, Steven Ray

2017-10-01

Capillary electrophoresis (CE) can provide high separation efficiency with very simple instrumentation, but has yet to be explored regarding oxysterols/cholesterol. Cholesterol and 25-hydroxycholesterol (both are 4-ene-3-ketosteroids) were quantitatively transformed into hydrazones using Girard P reagent after enzymatic oxidation by cholesterol oxidase. Separation was achieved using non-aqueous capillary electrophoresis with UV detection at 280nm; the "charge-tagging" Girard P reagent ensured both charge and chromophore (which are requirements for CE-UV). Excess reagent was also separated from the two analytes, eliminating the need for removal prior to the analysis. The compounds were separated in less than 5min with excellent separation efficiency, using separation electrolytes fully compatible with mass spectrometry. The CE-UV method was used to optimize steps for charge-tagging, revealing that the procedure is affected by the analyte/reagent ratio and reaction time, but also the analyte structure. Copyright © 2017 Elsevier B.V. All rights reserved.

Nailfold video-capillaroscopy in systemic sclerosis.

PubMed

Cutolo, M; Pizzorni, C; Sulli, A

2004-12-01

The Raynaud's phenomenon (RP) is the most common and significant clinical condition supporting microvascular analysis as soon as possible. Microvascular involvement is a key feature of RP, and several rheumatic diseases are characterized by the presence of the RP. Nailfold capillary microscopy shows an impressive cost/effectiveness ratio: it is simple, noninvasive and inexpensive.Well-recognized videocapillaroscopic patterns (NVC) have been described mainly in scleroderma (SSc) patients complaining of a secondary RP. The peripheral microvascular damage in SSc is characterized by increasing structural alterations of the capillaries (giant capillaries and microhemorrhages) with progressive decrease of their density. The detection of the scleroderma NCV allows early differentiation between primary RP (functional, not disease associated), and secondary RP (disease associated). Other major NVC patterns have been described in the field of rheumatic diseases. Interestingly, correlations are evident between the NCV and the clinical symptoms, severity of the disease and the laboratory findings. Further clinical and epidemiological studies, as well as a standardized and computerized quantitation of the observed damages are required.

Elasto-capillary windlass: from spider web to synthetic actuators

NASA Astrophysics Data System (ADS)

Elettro, Hervé; Antkowiak, Arnaud; Neukirch, Sébastien; Vollrath, Fritz; Institut D'Alembert Team; Oxford Silk Group Team

2015-03-01

Spiders' threads display a wide range of materials properties. The glue-covered araneid capture silk is unique among all silks because it is self tensing and remains taut even if compressed, allowing both thread and web to be in a constant state of tension. Here we demonstrate how this effect is achieved by unraveling the physics allowing the nanolitre glue droplets straddling the silk thread to induce buckling, coiling and spooling of the core filaments. Our model examines this windlass activation as a structural phase transition, which shows that fibre spooling results from the interplay between elasticity and capillarity. Fibre size is the key as such a capillary windlass requires micrometer-sized fibres in order to function. Our synthetic capillary windlasses point towards design principles for new bioinspired synthetic actuators. The present work was supported by ANR Grant ANR-09-JCJC-0022-01, ``La Ville de Paris - Programme Emergence,'' Royal Society International Exchanges Scheme 2013/R1 Grant IE130506, and the PEPS PTI program from CNRS.

Structure and composition of pulmonary arteries, capillaries and veins

PubMed Central

2013-01-01

The pulmonary vasculature is comprised of three anatomic compartments connected in series: the arterial tree, an extensive capillary bed, and the venular tree. Although in general this vasculature is thin-walled, structure is nonetheless complex. Contributions to structure (and thus potentially to function) from cells other than endothelial and smooth muscle cells as well as those from the extracellular matrix should be considered. This review is multifaceted, bringing together information regarding 1) classification of pulmonary vessels, 2) branching geometry in the pulmonary vascular tree, 3) a quantitative view of structure based on morphometry of the vascular wall, 4) the relationship of nerves, a variety of interstitial cells, matrix proteins, and striated myocytes to smooth muscle and endothelium in the vascular wall, 5) heterogeneity within cell populations and between vascular compartments, 6) homo- and heterotypic cell-cell junctional complexes, and 7) the relation of the pulmonary vasculature to that of airways. These issues for pulmonary vascular structure are compared, when data is available, across species from human to mouse and shrew. Data from studies utilizing vascular casting, light and electron microscopy, as well as models developed from those data, are discussed. Finally, the need for rigorous quantitative approaches to study of vascular structure in lung is highlighted. PMID:23606929

Laser illumination of multiple capillaries that form a waveguide

DOEpatents

Dhadwal, Harbans S.; Quesada, Mark A.; Studier, F. William

1998-08-04

A system and method are disclosed for efficient laser illumination of the interiors of multiple capillaries simultaneously, and collection of light emitted from them. Capillaries in a parallel array can form an optical waveguide wherein refraction at the cylindrical surfaces confines side-on illuminating light to the core of each successive capillary in the array. Methods are provided for determining conditions where capillaries will form a waveguide and for assessing and minimizing losses due to reflection. Light can be delivered to the arrayed capillaries through an integrated fiber optic transmitter or through a pair of such transmitters aligned coaxially at opposite sides of the array. Light emitted from materials within the capillaries can be carried to a detection system through optical fibers, each of which collects light from a single capillary, with little cross talk between the capillaries. The collection ends of the optical fibers can be in a parallel array with the same spacing as the capillary array, so that the collection fibers can all be aligned to the capillaries simultaneously. Applicability includes improving the efficiency of many analytical methods that use capillaries, including particularly high-throughput DNA sequencing and diagnostic methods based on capillary electrophoresis.

Laser illumination of multiple capillaries that form a waveguide

DOEpatents

Dhadwal, H.S.; Quesada, M.A.; Studier, F.W.

1998-08-04

A system and method are disclosed for efficient laser illumination of the interiors of multiple capillaries simultaneously, and collection of light emitted from them. Capillaries in a parallel array can form an optical waveguide wherein refraction at the cylindrical surfaces confines side-on illuminating light to the core of each successive capillary in the array. Methods are provided for determining conditions where capillaries will form a waveguide and for assessing and minimizing losses due to reflection. Light can be delivered to the arrayed capillaries through an integrated fiber optic transmitter or through a pair of such transmitters aligned coaxially at opposite sides of the array. Light emitted from materials within the capillaries can be carried to a detection system through optical fibers, each of which collects light from a single capillary, with little cross talk between the capillaries. The collection ends of the optical fibers can be in a parallel array with the same spacing as the capillary array, so that the collection fibers can all be aligned to the capillaries simultaneously. Applicability includes improving the efficiency of many analytical methods that use capillaries, including particularly high-throughput DNA sequencing and diagnostic methods based on capillary electrophoresis. 35 figs.

Device to improve detection in electro-chromatography

DOEpatents

Garguilo, Michael G.; Paul, Phillip H.; Rakestraw, David J.

2000-01-01

Apparatus and method for improving the resolution of non-pressure driven capillary chromatographic systems, and particularly for capillary electrochromatography (CEC) systems. By reducing the cross-sectional area of a packed capillary column by means of a second open capillary contiguous with the outlet end of a packed capillary column, where the packed capillary column has a cross sectional area of between about 2 and 5 times that of the open capillary column, the phenomenon of band broadening in the transition region between the open capillary and the packed capillary column, where the individual components of the mixture are analyzed, can be eliminated, thereby providing for a significant improvement in resolution and more accurate detection and analysis.

Device to improve detection in electro-chromatography

DOEpatents

Garguilo, Michael G.; Paul, Phillip H.; Rakestraw, David J.

2002-01-01

Apparatus and method for improving the resolution of non-pressure driven capillary chromatographic systems, and particularly for capillary electrochromatography (CEC) systems. By reducing the cross-sectional area of a packed capillary column by means of a second open capillary contiguous with the outlet end of a packed capillary column, where the packed capillary column has a cross sectional area of between about 2 and 5 times that of the open capillary column, the phenomenon of band broadening in the transition region between the open capillary and the packed capillary column, where the individual components of the mixture are analyzed, can be eliminated, thereby providing for a significant improvement in resolution and more accurate detection and analysis.

Sheathless interface for coupling capillary electrophoresis with mass spectrometry

DOEpatents

Wang, Chenchen; Tang, Keqi; Smith, Richard D.

2014-06-17

A sheathless interface for coupling capillary electrophoresis (CE) with mass spectrometry is disclosed. The sheathless interface includes a separation capillary for performing CE separation and an emitter capillary for electrospray ionization. A portion of the emitter capillary is porous or, alternatively, is coated to form an electrically conductive surface. A section of the emitter capillary is disposed within the separation capillary, forming a joint. A metal tube, containing a conductive liquid, encloses the joint.

Ultraflexible nanostructures and implications for future nanorobots

NASA Astrophysics Data System (ADS)

Cohn, Robert W.; Panchapakesan, Balaji

2016-05-01

Several high aspect ratio nanostructures have been made by capillary force directed self-assembly including polymeric nanofiber air-bridges, trampoline-like membranes, microsphere-beaded nanofibers, and intermetallic nanoneedles. Arrays of polymer air-bridges form in seconds by simply hand brushing a bead of polymeric liquid over an array of micropillars. The domination of capillary force that is thinning unstable capillary bridges leads to uniform arrays of nanofiber air-bridges. Similarly, arrays of vertically oriented Ag2Ga nanoneedles have been formed by dipping silvercoated arrays of pyramidal silicon into melted gallium. Force-displacement measurements of these structures are presented. These nanostructures, especially when compressively or torsionally buckled, have extremely low stiffnesses, motion due to thermal fluctuations that is relatively easily detected, and the ability to move great distances for very small changes in applied force. Nanofibers with bead-on-a-string structure, where the beads are micron diameter and loaded with magnetic iron oxide (maghemite), are shown to be simply viewable under optical microscopes, have micronewton/ m stiffness, and have ultralow torsional stiffnesses enabling the bead to be rotated numerous revolutions without breaking. Combination of these high aspect ratio structures with stretched elastomers offer interesting possibilities for robotic actuation and locomotion. Polydimethylsiloxane loaded with nanomaterials, e.g. nanotubes, graphene or MoS2, can be efficiently heated with directed light. Heating produces considerable force through the thermoelastic effect, and this force can be used for continuous translation or to trigger reversible elastic buckling of the nanostructures. The remote stimulation of motion with light provides a possible mechanism for producing cooperative behavior between swarms of semiautonomous nanorobots.

NASAL FILTERING OF FINE PARTICLES IN CHILDREN VS. ADULTS

EPA Science Inventory

Nasal efficiency for removing fine particles may be affected by developmental changes in nasal structure associated with age. In healthy Caucasian children (age 6-13, n=17) and adults (age 18-28, n=11) we measured the fractional deposition (DF) of fine particles (1 and 2um MMAD)...

Fine Structure of Dark Energy and New Physics

DOE PAGES

Jejjala, Vishnu; Kavic, Michael; Minic, Djordje

2007-01-01

Following our recent work on the cosmological constant problem, in this letter we make a specific proposal regarding the fine structure (i.e., the spectrum) of dark energy. The proposal is motivated by a deep analogy between the blackbody radiation problem, which led to the development of quantum theory, and the cosmological constant problem, for which we have recently argued calls for a conceptual extension of the quantum theory. We argue that the fine structure of dark energy is governed by a Wien distribution, indicating its dual quantum and classical nature. We discuss observational consequences of such a picture of darkmore » energy and constrain the distribution function.« less

Quantum-gravity predictions for the fine-structure constant

NASA Astrophysics Data System (ADS)

Eichhorn, Astrid; Held, Aaron; Wetterich, Christof

2018-07-01

Asymptotically safe quantum fluctuations of gravity can uniquely determine the value of the gauge coupling for a large class of grand unified models. In turn, this makes the electromagnetic fine-structure constant calculable. The balance of gravity and matter fluctuations results in a fixed point for the running of the gauge coupling. It is approached as the momentum scale is lowered in the transplanckian regime, leading to a uniquely predicted value of the gauge coupling at the Planck scale. The precise value of the predicted fine-structure constant depends on the matter content of the grand unified model. It is proportional to the gravitational fluctuation effects for which computational uncertainties remain to be settled.

Excitonic fine-structure splitting in telecom-wavelength InAs/GaAs quantum dots: Statistical distribution and height-dependence

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goldmann, Elias, E-mail: goldmann@itp.uni-bremen.de; Barthel, Stefan; Florian, Matthias

The variation of the excitonic fine-structure splitting is studied for semiconductor quantum dots under the influence of a strain-reducing layer, utilized to shift the emission wavelength of the excitonic transition into the telecom-wavelength regime of 1.3–1.5 μm. By means of a sp{sup 3}s{sup *}-tight-binding model and configuration interaction, we calculate wavelength shifts and fine-structure splittings for various quantum dot geometries. We find the splittings remaining small and even decreasing with strain-reducing layer composition for quantum dots with large height. Combined with an observed increased emission efficiency, the applicability for generation of entanglement photons is persistent.

Effect of a transient period of ischemia on myocardial cells. II. Fine structure during the first few minutes of reflow.

PubMed

Kloner, R A; Ganote, C E; Whalen, D A; Jennings, R B

1974-03-01

Changes produced in the posterior papillary muscle of the dog following 40 minutes of circumflex artery occlusion and 0 to 20 minutes of blood reflow were studied by electron miroscopy. With no reflow of blood, myocardial cells were modestly swollen, contained amorphous matrix densities in the mitochondria, had aggregation and margination of nuclear chromatin and relaxation of myofibrils. With as little as 2 minutes of blood reflow, cells developed contraction bands and were greatly swollen due to a generalized increase in sarcoplasmic space, formation of vacuoles and swelling of mitochondria. Frequently, cell membranes were lifted away from the myofibers, forming large subsarcolemmal blebs which appeared capable of compressing adjacent capillaries. The extracellular space did not appear to be enlarged, and the marked tissue edema found after reflow was due primarily to accumulation of intracellular fluid. In addition to explosive cell swelling, there was, over the 2- to 20-minute period of reflow, a progressive increase in size and number of granular mitochondrial dense bodies of the calcium accumulation type. No significant changes in lysosomes were observed. The speed with which the morphologic changes developed during very early reflow periods suggests that irreversible ischemic injury produces a defect in cell volume regulation during the phase of ischemia and that this defect becomes manifest if arterial flow is restored to the affected cells.

A tale of two pectins: Diverse fine structures can result from identical processive PME treatments on similar high DM subtrates

USDA-ARS?s Scientific Manuscript database

The effects of a processive pectin-methylesterase treatment on two different pectins, both possessing a high degree of methylesterification, were investigated. While the starting samples were purportedly very similar in fine structure, and even though the sample-averaged degree of methylesterificati...

Temporal Fine Structure and Applications to Cochlear Implants

ERIC Educational Resources Information Center

Li, Xing

2013-01-01

Complex broadband sounds are decomposed by the auditory filters into a series of relatively narrowband signals, each of which conveys information about the sound by time-varying features. The slow changes in the overall amplitude constitute envelope, while the more rapid events, such as zero crossings, constitute temporal fine structure (TFS).…

Laser Spectroscopy of the Fine-Structure Splitting in the 2^{3}P_{J} Levels of ^{4}He.

PubMed

Zheng, X; Sun, Y R; Chen, J-J; Jiang, W; Pachucki, K; Hu, S-M

2017-02-10

The fine-structure splitting in the 2^{3}P_{J} (J=0, 1, 2) levels of ^{4}He is of great interest for tests of quantum electrodynamics and for the determination of the fine-structure constant α. The 2^{3}P_{0}-2^{3}P_{2} and 2^{3}P_{1}-2^{3}P_{2} intervals are measured by laser spectroscopy of the ^{3}P_{J}-2^{3}S_{1} transitions at 1083 nm in an atomic beam, and are determined to be 31 908 130.98±0.13  kHz and 2 291 177.56±0.19  kHz, respectively. Compared with calculations, which include terms up to α^{5}Ry, the deviation for the α-sensitive interval 2^{3}P_{0}-2^{3}P_{2} is only 0.22 kHz. It opens the window for further improvement of theoretical predictions and an independent determination of the fine-structure constant α with a precision of 2×10^{-9}.

QUIESCENT PROMINENCES IN THE ERA OF ALMA: SIMULATED OBSERVATIONS USING THE 3D WHOLE-PROMINENCE FINE STRUCTURE MODEL

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gunár, Stanislav; Heinzel, Petr; Mackay, Duncan H.

2016-12-20

We use the detailed 3D whole-prominence fine structure model to produce the first simulated high-resolution ALMA observations of a modeled quiescent solar prominence. The maps of synthetic brightness temperature and optical thickness shown in the present paper are produced using a visualization method for synthesis of the submillimeter/millimeter radio continua. We have obtained the simulated observations of both the prominence at the limb and the filament on the disk at wavelengths covering a broad range that encompasses the full potential of ALMA. We demonstrate here extent to which the small-scale and large-scale prominence and filament structures will be visible inmore » the ALMA observations spanning both the optically thin and thick regimes. We analyze the relationship between the brightness and kinetic temperature of the prominence plasma. We also illustrate the opportunities ALMA will provide for studying the thermal structure of the prominence plasma from the cores of the cool prominence fine structure to the prominence–corona transition region. In addition, we show that detailed 3D modeling of entire prominences with their numerous fine structures will be important for the correct interpretation of future ALMA observations of prominences.« less

In Vivo Microscopy Reveals Extensive Embedding of Capillaries within the Sarcolemma of Skeletal Muscle Fibers

PubMed Central

Glancy, Brian; Hsu, Li-Yueh; Dao, Lam; Bakalar, Matthew; French, Stephanie; Chess, David J.; Taylor, Joni L.; Picard, Martin; Aponte, Angel; Daniels, Mathew P.; Esfahani, Shervin; Cushman, Samuel; Balaban, Robert S.

2013-01-01

Objective To provide insight into mitochondrial function in vivo, we evaluated the 3D spatial relationship between capillaries, mitochondria, and muscle fibers in live mice. Methods 3D volumes of in vivo murine Tibialis anterior muscles were imaged by multi-photon microscopy (MPM). Muscle fiber type, mitochondrial distribution, number of capillaries, and capillary-to-fiber contact were assessed. The role of myoglobin-facilitated diffusion was examined in myoglobin knockout mice. Distribution of GLUT4 was also evaluated in the context of the capillary and mitochondrial network. Results MPM revealed that 43.6 ± 3.3% of oxidative fiber capillaries had ≥ 50% of their circumference embedded in a groove in the sarcolemma, in vivo. Embedded capillaries were tightly associated with dense mitochondrial populations lateral to capillary grooves and nearly absent below the groove. Mitochondrial distribution, number of embedded capillaries, and capillary-to-fiber contact were proportional to fiber oxidative capacity and unaffected by myoglobin knockout. GLUT4 did not preferentially localize to embedded capillaries. Conclusions Embedding capillaries in the sarcolemma may provide a regulatory mechanism to optimize delivery of oxygen to heterogeneous groups of muscle fibers. We hypothesize that mitochondria locate to paravascular regions due to myofibril voids created by embedded capillaries, not to enhance the delivery of oxygen to the mitochondria. PMID:25279425

Demonstrating the Uneven Importance of Fine-Scale Forest Structure on Snow Distributions using High Resolution Modeling

NASA Astrophysics Data System (ADS)

Broxton, P. D.; Harpold, A. A.; van Leeuwen, W.; Biederman, J. A.

2016-12-01

Quantifying the amount of snow in forested mountainous environments, as well as how it may change due to warming and forest disturbance, is critical given its importance for water supply and ecosystem health. Forest canopies affect snow accumulation and ablation in ways that are difficult to observe and model. Furthermore, fine-scale forest structure can accentuate or diminish the effects of forest-snow interactions. Despite decades of research demonstrating the importance of fine-scale forest structure (e.g. canopy edges and gaps) on snow, we still lack a comprehensive understanding of where and when forest structure has the largest impact on snowpack mass and energy budgets. Here, we use a hyper-resolution (1 meter spatial resolution) mass and energy balance snow model called the Snow Physics and Laser Mapping (SnowPALM) model along with LIDAR-derived forest structure to determine where spatial variability of fine-scale forest structure has the largest influence on large scale mass and energy budgets. SnowPALM was set up and calibrated at sites representing diverse climates in New Mexico, Arizona, and California. Then, we compared simulations at different model resolutions (i.e. 1, 10, and 100 m) to elucidate the effects of including versus not including information about fine scale canopy structure. These experiments were repeated for different prescribed topographies (i.e. flat, 30% slope north, and south-facing) at each site. Higher resolution simulations had more snow at lower canopy cover, with the opposite being true at high canopy cover. Furthermore, there is considerable scatter, indicating that different canopy arrangements can lead to different amounts of snow, even when the overall canopy coverage is the same. This modeling is contributing to the development of a high resolution machine learning algorithm called the Snow Water Artificial Network (SWANN) model to generate predictions of snow distributions over much larger domains, which has implications for improving land surface models that do not currently resolve or parameterize fine-scale canopy structure. In addition, these findings have implications for understanding the potential of different forest management strategies (i.e. thinning) based on local topography and climate to maximize the amount and retention of snow.

Capillary electrophoretic analysis of synthetic short-chain oligoribonucleotides.

PubMed

Cellai, L; Onori, A M; Desiderio, C; Fanali, S

1998-12-01

Thirty synthetic oligoribonucleotides, 3 to 18 nucleotides (nt) long, were analyzed by capillary electrophoresis, under nondenaturing conditions, using a commercial kit. The migration time t(m) was dependent on nt length and composition, capillary length, operating temperature, and type of sieving polymer. Under fixed experimental conditions, the t(m) proved predictable by the equation: t(m) = [0.22(n-1) + 6.14A/n + 6.86G/n + 3.61 (C+U)/n] min, for n>3, where A/n, G/n, C/n, U/n is the frequency of each type of nt within the oligonucleotide (ONT). The equation accounts for the influence of charge-to-mass ratio on t(m), but not for structural effects, if present. This approximation is acceptable for short ONTs. The possibility of detecting n+1, n-1, n-2 impurities, having predicted the t(m), is of crucial importance in assessing the purity of synthetic ONTs dedicated to structural studies. This appears to be feasible. High resolution was shown among homologous series of ONTs of increasing length, and in some cases, even within groups of ONTs of the same length but different composition. The addition of 7 M urea to the buffer, as denaturing agent, accelerates the t(m) and significantly lowers the resolution for the shortest ONTs. It was also possible to monitor the state of association of mixtures of RNA and DNA sequence-complementary strands.

Method and apparatus for optimized sampling of volatilizable target substances

DOEpatents

Lindgren, Eric R.; Phelan, James M.

2004-10-12

An apparatus for capturing, from gases such as soil gas, target analytes. Target analytes may include emanations from explosive materials or from residues of explosive materials. The apparatus employs principles of sorption common to solid phase microextraction, and is best used in conjunction with analysis means such as a gas chromatograph. To sorb target analytes, the apparatus functions using various sorptive structures to capture target analyte. Depending upon the embodiment, those structures may include a capillary tube including an interior surface on which sorptive material (similar to that on the surface of a SPME fiber) is supported (along with means for moving gases through the capillary tube so that the gases come into close proximity to the sorptive material). In one disclosed embodiment, at least one such sorptive structure is associated with an enclosure including an opening in communication with the surface of a soil region potentially contaminated with buried explosive material such as unexploded ordnance. Emanations from explosive materials can pass into and accumulate in the enclosure where they are sorbed by the sorptive structures. Also disclosed is the use of heating means such as microwave horns to drive target analytes into the soil gas from solid and liquid phase components of the soil.

Temperature and saturation dependence in the vapor sensing of butterfly wing scales.

PubMed

Kertész, K; Piszter, G; Jakab, E; Bálint, Zs; Vértesy, Z; Biró, L P

2014-06-01

The sensing of gasses/vapors in the ambient air is the focus of attention due to the need to monitor our everyday environment. Photonic crystals are sensing materials of the future because of their strong light-manipulating properties. Natural photonic structures are well-suited materials for testing detection principles because they are significantly cheaper than artificial photonic structures and are available in larger sizes. Additionally, natural photonic structures may provide new ideas for developing novel artificial photonic nanoarchitectures with improved properties. In the present paper, we discuss the effects arising from the sensor temperature and the vapor concentration in air during measurements with a photonic crystal-type optical gas sensor. Our results shed light on the sources of discrepancy between simulated and experimental sensing behaviors of photonic crystal-type structures. Through capillary condensation, the vapors will condensate to a liquid state inside the nanocavities. Due to the temperature and radius of curvature dependence of capillary condensation, the measured signals are affected by the sensor temperature as well as by the presence of a nanocavity size distribution. The sensing materials used are natural photonic nanoarchitectures present in the wing scales of blue butterflies. Copyright © 2014 Elsevier B.V. All rights reserved.

Relaxation of the structure of simple metal ion complexes in aqueous solutions at up to supercritical conditions

USGS Publications Warehouse

Mayanovic, Robert A.; Jayanetti, Sumedha; Anderson, Alan J.; Bassett, William A.; Chou, I.-Ming

2003-01-01

Recently x-ray absorption fine structure (XAFS) studies of various ions in aqueous solutions showed a variation of cation-ligand bond lengths, often coupled with other structure changes, with increasing temperatures. Thus, the variations of the structure of several metal ion complexes with temperature based on observations from the X-ray absorption fine structure (XAFS) studies in the hope that it will stimulate the development of either first- principles theory or molecular dynamics simulations that might adequately describes these results are discussed.

Optimized Structures for Low-Profile Phase Change Thermal Spreaders

NASA Astrophysics Data System (ADS)

Sharratt, Stephen Andrew

Thin, low-profile phase change thermal spreaders can provide cooling solutions for some of today's most pressing heat flux dissipation issues. These thermal issues are only expected to increase as future electronic circuitry requirements lead to denser and potentially 3D chip packaging. Phase change based heat spreaders, such as heat pipes or vapor chambers, can provide a practical solution for effectively dissipating large heat fluxes. This thesis reports a comprehensive study of state-of-the-art capillary pumped wick structures using computational modeling, micro wick fabrication, and experimental analysis. Modeling efforts focus on predicting the shape of the liquid meniscus inside a complicated 3D wick structure. It is shown that this liquid shape can drastically affect the wick's thermal resistance. In addition, knowledge of the liquid meniscus shape allows for the computation of key parameters such as permeability and capillary pressure which are necessary for predicting the maximum heat flux. After the model is validated by comparison to experimental results, the wick structure is optimized so as to decrease overall wick thermal resistance and increase the maximum capillary limited heat flux before dryout. The optimized structures are then fabricated out of both silicon and copper using both traditional and novel micro-fabrication techniques. The wicks are made super-hydrophilic using chemical and thermal oxidation schemes. A sintered monolayer of Cu particles is fabricated and analyzed as well. The fabricated wick structures are experimentally tested for their heat transfer performance inside a well controlled copper vacuum chamber. Heat fluxes as high as 170 W/cm2 are realized for Cu wicks with structure heights of 100 μm. The structures optimized for both minimized thermal resistance and high liquid supply ability perform much better than their non-optimized counterparts. The super-hydrophilic oxidation scheme is found to drastically increase the maximum heat flux and decrease thermal resistance. This research provides key insights as to how to optimize heat pipe structures to minimize thermal resistance and increase maximum heat flux. These thin wick structures can also be combined with a thicker liquid supply layer so that thin, low-resistance evaporator layers can be constructed and higher heat fluxes realized. The work presented in this thesis can be used to aid in the development of high-performance phase change thermal spreaders, allowing for temperature control of a variety of powerful electronic components.

CSE-MECC two-dimensional capillary electrophoresis analysis of proteins in the mouse tumor cell (AtT-20) homogenate

PubMed Central

Chen, Xingguo; Fazal, Md. Abul; Dovichi, Norman J.

2007-01-01

Two-dimensional capillary electrophoresis was used for the separation of proteins and biogenic amines from the mouse AtT-20 cell line. The first-dimension capillary contained a TRIS-CHES-SDS-dextran buffer to perform capillary sieving electrophoresis, which is based on molecular weight of proteins. The second-dimension capillary contained a TRIS-CHES-SDS buffer for micel1ar electrokinetic capillary chromatography. After a 61 seconds preliminary separation, fractions from the first-dimension capillary were successively transferred to the second-dimension capillary, where they further separated by MECC. The two-dimensional separation required 60 minutes. PMID:17637850

Lung capillary injury and repair in left heart disease: a new target for therapy?

PubMed

Azarbar, Sayena; Dupuis, Jocelyn

2014-07-01

The lungs are the primary organs affected in LHD (left heart disease). Increased left atrial pressure leads to pulmonary alveolar-capillary stress failure, resulting in cycles of alveolar wall injury and repair. The reparative process causes the proliferation of MYFs (myofibroblasts) with fibrosis and extracellular matrix deposition, resulting in thickening of the alveolar wall. Although the resultant reduction in vascular permeability is initially protective against pulmonary oedema, the process becomes maladaptive causing a restrictive lung syndrome with impaired gas exchange. This pathological process may also contribute to PH (pulmonary hypertension) due to LHD. Few clinical trials have specifically evaluated lung structural remodelling and the effect of related therapies in LHD. Currently approved treatment for chronic HF (heart failure) may have direct beneficial effects on lung structural remodelling. In the future, novel therapies specifically targeting the remodelling processes may potentially be utilized. In the present review, we summarize data supporting the clinical importance and pathophysiological mechanisms of lung structural remodelling in LHD and propose that this pathophysiological process should be explored further in pre-clinical studies and future therapeutic trials.

Micro/Nano-Scale Phase Change Systems for Thermal Management and Solar Energy Conversion Applications

NASA Astrophysics Data System (ADS)

Coso, Dusan

The first part of the dissertation presents a study that implements micro and nano scale engineered surfaces for enhancement of evaporation and boiling phase change heat transfer in both capillary wick structures and pool boiling systems. Capillary wicking surfaces are integral components of heat pipes and vapor chamber thermal spreaders often used for thermal management of microelectronic devices. In addition, pool boiling systems can be encountered in immersion cooling systems which are becoming more commonly investigated for thermal management applications of microelectronic devices and even data centers. The latent heat associated with the change of state from liquid to vapor, and the small temperature differences required to drive this process yield great heat transfer characteristics. Additionally, since no external energy is required to drive the phase change process, these systems are great for portable devices and favorable for reduction of cost and energy consumption over alternate thermal management technologies. Most state of the art capillary wicks used in these devices are typically constructed from sintered copper media. These porous structures yield high surface areas of thin liquid film where evaporation occurs, thus promoting phase change heat transfer. However, thermal interfaces at particle point contacts formed during the sintering process and complex liquid/vapor flow within these wick structures yield high thermal and liquid flow resistances and limit the maximum heat flux they can dissipate. In capillary wicks the maximum heat flux is typically governed by the capillary or boiling limits and engineering surfaces that delay these limitations and yield structures with large surface areas of thin liquid film where phase change heat transfer is promoted is highly desired. In this study, biporous media consisting of microscale pin fins separated by microchannels are examined as candidate structures for the evaporator wick of a vapor chamber heat pipe. Smaller pores are used to generate high capillary suction, while larger microchannels are used to alleviate flow resistance. The heat transfer coefficient is found to depend on the area coverage of a liquid film with thickness on the order of a few microns near the meniscus of the triple phase contact line. We manipulate the area coverage and film thickness by varying the surface area-to-volume ratio through the use of microstructuring. In some samples, a transition from evaporative heat transfer to nucleate boiling is observed. While it is difficult to identify when the transition occurs, one can identify regimes where evaporation dominates over nucleate boiling and vice versa. Heat fluxes of 277.0 (+/- 9.7) W/cm2 can be dissipated by wicks with heaters of area 1 cm2, while heat fluxes up to 733.1 (+/- 103.4) W/cm2 can be dissipated by wicks with smaller heaters intended to simulate local hot-spots. In pool boiling systems that are encountered in immersion cooling applications, the heat transfer coefficient (HTC) is governed by the bubble nucleation site density and the agitation in the liquid/vapor flow these bubbles produce when they detach from the surface. The nucleation site density and release rate is usually determined by the surface morphology. Another important parameter in pool boiling systems is the maximum heat flux (CHF) that can safely be dissipated. In practice, this quantity is about two orders of magnitude smaller than limitations suggested by kinetic theory. For essentially infinite, smooth, well wetted surfaces, hydrodynamic instability theories capturing liquid/vapor interactions away from the heated surface have been successful in predicting CHF. On finite micro and nano structured surfaces where applying the hydrodynamic theory formulation is not easily justified, other effects may contribute to phase change heat transfer characteristics. Here, we also present a pool boiling study on biporous microstructured surfaces used in capillary wick experiments. Structures are manipulated by reduction of pore size to determine if increased capillary pressure can enhance rewetting from heater edges and delay CHF. A comparative study between the two experimental systems indicates that while the capillary limitation is significant in capillary wick experiments, for these well wetted microstructured surfaces used in pool boiling systems the hydrodynamic limitation defined based on heater size causes the occurrence of CHF. Other hierarchical nanowire surfaces containing periodic microscale cavities are investigated as well and are seen to yield a ˜2.4 fold increase in heat transfer coefficient characteristics while not compromising CHF compared to surfaces where cavities are not present. These studies indicate pathways for enhancement of heat transfer coefficient via implementing hierarchical structures, while no clear method in increasing CHF is determined for finite size surfaces of various morphologies. In the second part of this dissertation, solar energy storage is sought in 'phase change' of photochromic molecular systems: the storage of solar energy in the chemical bonds of photosensitive molecules (a photochemical reaction) and subsequent recovery of the energy in a back reaction in the form of heat, reversibly. These molecular systems are interesting alternatives to photovoltaic and solar thermal technologies which cannot satisfy the needs of load leveling, or for portable municipal heating applications. Typically made of organic compounds, these molecules have become known for rapid decomposition, short energy storage time scales and poor energy storing efficiencies. Thus, they have been abandoned as practical solar energy storage systems in the past several decades. On the other hand, organometallic molecular systems have not been extensively probed for these applications. Recent research has indicated that organometallic (fulvalene)diruthenium FvRu2 has demonstrated excellent energy storage characteristic and durability. Here, we report on a full cycle molecular solar thermal (MOST) microfluidic system based on a bis(1,1-dimethyltridecyl) substituted derivative of FvRu2 that allows for long term solar energy storage (110 J/g), and "on demand" energy release upon exposure to a catalyst. The microfluidic systems developed here are excellent for photoconversion characterization and scrutinizing potential catalysts and can be extended to studying many other molecular systems. The objective of the work presented here is to demonstrate that "on demand" solar energy storage and release in MOST systems is viable and motivate future research on other photochromic organometallic systems.

A Model-Based Approach for Microvasculature Structure Distortion Correction in Two-Photon Fluorescence Microscopy Images

PubMed Central

Dao, Lam; Glancy, Brian; Lucotte, Bertrand; Chang, Lin-Ching; Balaban, Robert S; Hsu, Li-Yueh

2015-01-01

SUMMARY This paper investigates a post-processing approach to correct spatial distortion in two-photon fluorescence microscopy images for vascular network reconstruction. It is aimed at in vivo imaging of large field-of-view, deep-tissue studies of vascular structures. Based on simple geometric modeling of the object-of-interest, a distortion function is directly estimated from the image volume by deconvolution analysis. Such distortion function is then applied to sub volumes of the image stack to adaptively adjust for spatially varying distortion and reduce the image blurring through blind deconvolution. The proposed technique was first evaluated in phantom imaging of fluorescent microspheres that are comparable in size to the underlying capillary vascular structures. The effectiveness of restoring three-dimensional spherical geometry of the microspheres using the estimated distortion function was compared with empirically measured point-spread function. Next, the proposed approach was applied to in vivo vascular imaging of mouse skeletal muscle to reduce the image distortion of the capillary structures. We show that the proposed method effectively improve the image quality and reduce spatially varying distortion that occurs in large field-of-view deep-tissue vascular dataset. The proposed method will help in qualitative interpretation and quantitative analysis of vascular structures from fluorescence microscopy images. PMID:26224257

Fabrication of Artificial Leaf to Develop Fluid Pump Driven by Surface Tension and Evaporation

NASA Astrophysics Data System (ADS)

Lee, Minki; Lim, Hosub; Lee, Jinkee

2017-11-01

Plants transport water from roots to leaves via xylem through transpiration, which is an evaporation process that occurs at the leaves. During transpiration, negative pressure can be generated by the porous structure of mesophyll cells in the leaves. Here, an artificial leaf mimicking structure using hydrogel, which has a nanoporous structure is fabricated. The cryogel method is used to develop a hierarchy structure on the nano- and microscale in the hydrogel media that is similar to the mesophyll cells and veins of a leaf, respectively. The theoretical model is analyzed to calculate the flow resistance in the artificial leaf, and compare the model with the experimental results. The experiment involves connecting a glass capillary tube at the bottom of the artificial leaf to observe the fluid velocity in the glass capillary tube generated by the negative pressure. The use of silicone oil as fluid instead of water to increase the flow resistance enables the measurement of negative pressure. The negative pressure of the artificial leaf is affected by several variables (e.g., pore size, wettability of the structure). Finally, by decreasing the pore size and increasing the wettability, the maximum negative pressure of the artificial leaf, -7.9 kPa is obtained.

Simple preparation of magnetic field-responsive structural colored Janus particles.

PubMed

Teshima, Midori; Seki, Takahiro; Takeoka, Yukikazu

2018-03-08

We established a simple method for preparing Janus particles displaying different structural colors using submicron-sized fine silica particles and magnetic nanoparticles composed of Fe 3 O 4 . A w/o emulsion is prepared by vortex-stirring a mixed aqueous solution of suspended fine silica particles and magnetic nanoparticles and of hexadecane containing an emulsifier. Subsequent drying of the emulsion on a hot plate using a magnetic stirrer provides a polydisperse particle aggregate displaying two different structural colors according to the ratio of the amount of fine silica particles to the amount of magnetic nanoparticles. This polydisperse particle aggregate can be converted into monodisperse particles simply by using a sieve made of stainless steel. In the presence of a magnet, the monodisperse Janus particles can change their orientation and can switch between two different structural colors.

The fine-structure intervals of (N-14)+ by far-infrared laser magnetic resonance

NASA Technical Reports Server (NTRS)

Brown, John M.; Varberg, Thomas D.; Evenson, Kenneth M.; Cooksy, Andrew L.

1994-01-01

The far-infrared laser magnetic resonance spectra associated with both fine-structure transitions in (N-14)+ in its ground P-3 state have been recorded. This is the first laboratory observation of the J = 1 left arrow 0 transition and its frequency has been determined two orders of magnitude more accurately than previously. The remeasurement of the J = 2 left arrow 1 spectrum revealed a small error in the previous laboratory measurements. The fine-structure splittings (free of hyperfine interactions) determined in this work are (delta)E(sub 10) = 1461.13190 (61) GHz, (delta)E(sub 21) = 2459.38006 (37) GHz. Zero-field transition frequencies which include the effects of hyperfine structure have also been calculated. Refined values for the hyperfine constants and the g(sub J) factors have been obtained.

Dynamical Study of Femtosecond-Laser-Ablated Liquid-Aluminum Nanoparticles Using Spatiotemporally Resolved X-Ray-Absorption Fine-Structure Spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oguri, Katsuya; Okano, Yasuaki; Nishikawa, Tadashi

2007-10-19

We study the temperature evolution of aluminum nanoparticles generated by femtosecond laser ablation with spatiotemporally resolved x-ray-absorption fine-structure spectroscopy. We successfully identify the nanoparticles based on the L-edge absorption fine structure of the ablation plume in combination with the dependence of the edge structure on the irradiation intensity and the expansion velocity of the plume. In particular, we show that the lattice temperature of the nanoparticles is estimated from the L-edge slope, and that its spatial dependence reflects the cooling of the nanoparticles during plume expansion. The results reveal that the emitted nanoparticles travel in a vacuum as a condensedmore » liquid phase with a lattice temperature of about 2500 to 4200 K in the early stage of plume expansion.« less

Insulin-induced changes in microvascular vasomotion and capillary recruitment are associated in humans.

PubMed

de Boer, Michiel P; Meijer, Rick I; Newman, John; Stehouwer, Coen D A; Eringa, Etto C; Smulders, Yvo M; Serné, Erik H

2014-07-01

Insulin-induced capillary recruitment is considered a significant regulator of overall insulin-stimulated glucose uptake. Insulin's action to recruit capillaries has been hypothesized to involve insulin-induced changes in vasomotion. Data directly linking vasomotion to capillary perfusion, however, are presently lacking. We, therefore, investigated whether insulin's actions on capillary recruitment and vasomotion were interrelated in a group of healthy individuals. We further assessed the role of capillary recruitment in the association between vasomotion and insulin-mediated glucose uptake. Changes in vasomotion and capillary density were determined by LDF and capillary videomicroscopy in skin, respectively, before and during a hyperinsulinemic euglycemic clamp in 19 healthy volunteers. Insulin-induced increase in the neurogenic vasomotion domain was positively related to insulin-augmented capillary recruitment (r = 0.51, p = 0.04), and both parameters were related to insulin-mediated glucose uptake (r = 0.47, p = 0.06 and r = 0.73, p = 0.001, respectively). The change in insulin-augmented capillary recruitment could, at least statistically, largely explain the association between the neurogenic domain and insulin-mediated glucose uptake. Insulin-induced changes in vasomotion and capillary recruitment are associated in healthy volunteers. These data suggest that insulin's action to recruit capillaries may in part involve action on the neurogenic vasomotion domain, thereby enhancing capillary perfusion and glucose uptake. © 2014 John Wiley & Sons Ltd.

Adaptive root foraging strategies along a boreal-temperate forest gradient.

PubMed

Ostonen, Ivika; Truu, Marika; Helmisaari, Heljä-Sisko; Lukac, Martin; Borken, Werner; Vanguelova, Elena; Godbold, Douglas L; Lõhmus, Krista; Zang, Ulrich; Tedersoo, Leho; Preem, Jens-Konrad; Rosenvald, Katrin; Aosaar, Jürgen; Armolaitis, Kęstutis; Frey, Jane; Kabral, Naima; Kukumägi, Mai; Leppälammi-Kujansuu, Jaana; Lindroos, Antti-Jussi; Merilä, Päivi; Napa, Ülle; Nöjd, Pekka; Parts, Kaarin; Uri, Veiko; Varik, Mats; Truu, Jaak

2017-08-01

The tree root-mycorhizosphere plays a key role in resource uptake, but also in the adaptation of forests to changing environments. The adaptive foraging mechanisms of ectomycorrhizal (EcM) and fine roots of Picea abies, Pinus sylvestris and Betula pendula were evaluated along a gradient from temperate to subarctic boreal forest (38 sites between latitudes 48°N and 69°N) in Europe. Variables describing tree resource uptake structures and processes (absorptive fine root biomass and morphology, nitrogen (N) concentration in absorptive roots, extramatrical mycelium (EMM) biomass, community structure of root-associated EcM fungi, soil and rhizosphere bacteria) were used to analyse relationships between root system functional traits and climate, soil and stand characteristics. Absorptive fine root biomass per stand basal area increased significantly from temperate to boreal forests, coinciding with longer and thinner root tips with higher tissue density, smaller EMM biomass per root length and a shift in soil microbial community structure. The soil carbon (C) : N ratio was found to explain most of the variability in absorptive fine root and EMM biomass, root tissue density, N concentration and rhizosphere bacterial community structure. We suggest a concept of absorptive fine root foraging strategies involving both qualitative and quantitative changes in the root-mycorrhiza-bacteria continuum along climate and soil C : N gradients. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

A preliminary investigation of projectile shape effects in hypervelocity impact of a double-sheet structure

NASA Technical Reports Server (NTRS)

Morrison, R. H.

1972-01-01

Impact tests of a sphere and several cylinders of various masses and fineness ratios, all of aluminum, fired into an aluminum double-sheet structure at velocities near 7 km/sec, show that a cylinder, impacting in the direction of its axis, is considerably more effective as a penetrator than a sphere. Impacts of three cylinders of equal mass, but different fineness ratios, produced holes through the structures' rear sheet, whereas impact of a sphere of the same mass did not. Moreover, it was found that to prevent rear-sheet penetration, the mass of the 1/2-fineness-ratio cylinder had to be reduced by a factor greater than three. Further tests wherein the cylinder diameter was held constant while the cylinder length was systematically reduced showed that a cylinder with a fineness ratio of 0.07 and a mass of only 1/7 that of the sphere was still capable of producing a hole in the rear sheet.

Clonal growth and fine-scale genetic structure in tanoak (Notholithocarpus densiflorus: Fagaceae)

Treesearch

Richard S. Dodd; Wasima Mayer; Alejandro Nettel; Zara Afzal-Rafii

2013-01-01

The combination of sprouting and reproduction by seed can have important consequences on fine-scale spatial distribution of genetic structure (SGS). SGS is an important consideration for species’ restoration because it determines the minimum distance among seed trees to maximize genetic diversity while not prejudicing locally adapted genotypes. Local environmental...

Cation distribution in NiZn-ferrite films via extended x-ray absorption fine structure

NASA Astrophysics Data System (ADS)

Harris, V. G.; Koon, N. C.; Williams, C. M.; Zhang, Q.; Abe, M.; Kirkland, J. P.

1996-04-01

We have applied extended x-ray absorption fine structure (EXAFS) spectroscopy to study the cation distribution in a series of spin-sprayed NiZn-ferrite films. A least-squares fitting of experimental EXAFS data with theoretical, multiple-scattering, EXAFS data allowed the quantitative determination of site distributions for all transition metal cations.

Precision microwave measurement of the 2(3)P(1)-2(3)P(0) interval in atomic helium: a determination of the fine-structure constant.

PubMed

George, M C; Lombardi, L D; Hessels, E A

2001-10-22

The 2(3)P(1)-to- 2(3)P(0) interval in atomic helium is measured using a thermal beam of metastable helium atoms excited to the 2(3)P state using a 1.08-microm diode laser. The 2(3)P(1)-to- 2(3)P(0) transition is driven by 29.6-GHz microwaves in a rectangular waveguide cavity. Our result of 29,616,950.9+/-0.9 kHz is the most precise measurement of helium 2(3)P fine structure. When compared to precise theory for this interval, this measurement leads to a determination of the fine-structure constant of 1/137.0359864(31).

Fine Structure of Reovirus Type 2

PubMed Central

Loh, Philip C.; Hohl, H. R.; Soergel, M.

1965-01-01

Loh, Philip C. (University of Hawaii, Honolulu), H. R. Hohl, and M. Soergel. Fine structure of reovirus type 2. J. Bacteriol. 89:1140–1144. 1965.—The fine structure reovirus type 2 was studied by electron microscopy with the negative-staining method. The virus has a mean diameter of 772 A and shows evidence of icosahedral shape and 5:3:2 symmetry. The particle is composed of a core, an inner layer, and a capsid composed of 92 elongated hollow capsomeres. These capsomeres have mean dimensions of 116 A × 110 A and a central hole 48 A in diameter. In size and architecture, reovirus type 2 is very similar to the other members (reoviruses types 1 and 3) of this group of animal viruses. Images PMID:14276109

Surface structure of imidazolium-based ionic liquids: Quantitative comparison between simulations and high-resolution RBS measurements.

PubMed

Nakajima, Kaoru; Nakanishi, Shunto; Lísal, Martin; Kimura, Kenji

2016-03-21

Elemental depth profiles of 1-alkyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([CnMIM][TFSI], n = 4, 6, 8) are measured using high-resolution Rutherford backscattering spectroscopy (HRBS). The profiles are compared with the results of molecular dynamics (MD) simulations. Both MD simulations and HRBS measurements show that the depth profiles deviate from the uniform stoichiometric composition in the surface region, showing preferential orientations of ions at the surface. The MD simulations qualitatively reproduce the observed HRBS profiles but the agreement is not satisfactory. The observed discrepancy is ascribed to the capillary waves. By taking account of the surface roughness induced by the capillary waves, the agreement becomes almost perfect.

Surface structure of imidazolium-based ionic liquids: Quantitative comparison between simulations and high-resolution RBS measurements

NASA Astrophysics Data System (ADS)

Nakajima, Kaoru; Nakanishi, Shunto; Lísal, Martin; Kimura, Kenji

2016-03-01

Elemental depth profiles of 1-alkyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([CnMIM][TFSI], n = 4, 6, 8) are measured using high-resolution Rutherford backscattering spectroscopy (HRBS). The profiles are compared with the results of molecular dynamics (MD) simulations. Both MD simulations and HRBS measurements show that the depth profiles deviate from the uniform stoichiometric composition in the surface region, showing preferential orientations of ions at the surface. The MD simulations qualitatively reproduce the observed HRBS profiles but the agreement is not satisfactory. The observed discrepancy is ascribed to the capillary waves. By taking account of the surface roughness induced by the capillary waves, the agreement becomes almost perfect.

Nine Years of Irrigation Cause Vegetation and Fine Root Shifts in a Water-Limited Pine Forest

PubMed Central

Herzog, Claude; Steffen, Jan; Graf Pannatier, Elisabeth; Hajdas, Irka; Brunner, Ivano

2014-01-01

Scots pines (Pinus sylvestris L.) in the inner-Alpine dry valleys of Switzerland have suffered from increased mortality during the past decades, which has been caused by longer and more frequent dry periods. In addition, a proceeding replacement of Scots pines by pubescent oaks (Quercus pubescens Willd.) has been observed. In 2003, an irrigation experiment was performed to track changes by reducing drought pressure on the natural pine forest. After nine years of irrigation, we observed major adaptations in the vegetation and shifts in Scots pine fine root abundance and structure. Irrigation permitted new plant species to assemble and promote canopy closure with a subsequent loss of herb and moss coverage. Fine root dry weight increased under irrigation and fine roots had a tendency to elongate. Structural composition of fine roots remained unaffected by irrigation, expressing preserved proportions of cellulose, lignin and phenolic substances. A shift to a more negative δ13C signal in the fine root C indicates an increased photosynthetic activity in irrigated pine trees. Using radiocarbon (14C) measurement, a reduced mean age of the fine roots in irrigated plots was revealed. The reason for this is either an increase in newly produced fine roots, supported by the increase in fine root biomass, or a reduced lifespan of fine roots which corresponds to an enhanced turnover rate. Overall, the responses belowground to irrigation are less conspicuous than the more rapid adaptations aboveground. Lagged and conservative adaptations of tree roots with decadal lifespans are challenging to detect, hence demanding for long-term surveys. Investigations concerning fine root turnover rate and degradation processes under a changing climate are crucial for a complete understanding of C cycling. PMID:24802642

Effect of Capillary Tube’s Shape on Capillary Rising Regime for Viscos Fluids

NASA Astrophysics Data System (ADS)

Soroush, F.; Moosavi, A.

2018-05-01

When properties of the displacing fluid are considered, the rising profile of the penetrating fluid in a capillary tube deviates from its classical Lucas-Washburn profile. Also, shape of capillary tube can affect the rising profile in different aspects. In this article, effect of capillary tube’s shape on the vertical capillary motion in presence of gravity is investigated by considering the properties of the displacing fluid. According to the fact that the differential equation of the capillary rising for a non-simple wall type is very difficult to solve analytically, a finite element simulation model is used for this study. After validation of the simulation model with an experiment that has been done with a simple capillary tube, shape of the capillary tube’s wall is changed in order to understand its effects on the capillary rising and different motion regimes that may appear according to different geometries. The main focus of this article is on the sinusoidal wall shapes and comparing them with a simple wall.

Means and method for capillary zone electrophoresis with laser-induced indirect fluorescence detection

DOEpatents

Yeung, Edward S.; Kuhr, Werner G.

1996-02-20

A means and method for capillary zone electrphoresis with laser-induced indirect fluorescence detection. A detector is positioned on the capillary tube of a capillary zone electrophoresis system. The detector includes a laser which generates a laser beam which is imposed upon a small portion of the capillary tube. Fluorescence of the elutant electromigrating through the capillary tube is indirectly detected and recorded.

Means and method for capillary zone electrophoresis with laser-induced indirect fluorescence detection

DOEpatents

Yeung, Edwards; Kuhr, Werner G.

1991-04-09

A means and method for capillary zone electrphoresis with laser-induced indirect fluorescence detection. A detector is positioned on the capillary tube of a capillary zone electrophoresis system. The detector includes a laser which generates a laser beam which is imposed upon a small portion of the capillary tube. Fluorescence of the elutant electromigrating through the capillary tube is indirectly detected and recorded.

Enhancing separation in short-capillary electrophoresis via pressure-driven backflow.

PubMed

Tian, Miaomiao; Wang, Yujia; Mohamed, Amara Camara; Guo, Liping; Yang, Li

2015-07-01

We present a novel easy-to-operate and efficient method to improve the separation efficiency in short-capillary electrophoresis by introducing steady backflow to counterbalance electro-osmotic flow without the use of any external pressure. The backflow was easily generated by tapering the capillary end, which was achieved by heating a straight capillary and stretching it with a constant force. We investigated the net fluidic transport rate under different tip lengths and separation voltages. Good run-to-run repeatability and capillary-to-capillary reproducibility of the present method were obtained with RSD less than 1.5%, indicating the stability of the fluid transport rate in the tapered capillary, which ensures the quantification and repeatability of capillary zone electrophoresis (CZE) analysis. Enhanced separation of the tapered short capillary electrophoresis was demonstrated by CZE analyzing amino acids and positional isomers. Baseline separations were achieved in less than 60 s using a tapered capillary with the effective length of 5 cm, while no separation was achieved using a normal capillary without a tapered tip. The present study provides a promising method to use pressure-driven backflow to enhance separation efficiency in short-capillary electrophoresis, which would be of potential value in a wide application for fast analysis of complex samples. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ectopic norrin induces growth of ocular capillaries and restores normal retinal angiogenesis in Norrie disease mutant mice.

PubMed

Ohlmann, Andreas; Scholz, Michael; Goldwich, Andreas; Chauhan, Bharesh K; Hudl, Kristiane; Ohlmann, Anne V; Zrenner, Eberhart; Berger, Wolfgang; Cvekl, Ales; Seeliger, Mathias W; Tamm, Ernst R

2005-02-16

Norrie disease is an X-linked retinal dysplasia that presents with congenital blindness, sensorineural deafness, and mental retardation. Norrin, the protein product of the Norrie disease gene (NDP), is a secreted protein of unknown biochemical function. Norrie disease (Ndp(y/-)) mutant mice that are deficient in norrin develop blindness, show a distinct failure in retinal angiogenesis, and completely lack the deep capillary layers of the retina. We show here that the transgenic expression of ectopic norrin under control of a lens-specific promoter restores the formation of a normal retinal vascular network in Ndp(y/-) mutant mice. The improvement in structure correlates with restoration of neuronal function in the retina. In addition, lenses of transgenic mice with ectopic expression of norrin show significantly more capillaries in the hyaloid vasculature that surrounds the lens during development. In vitro, lenses of transgenic mice in coculture with microvascular endothelial cells induce proliferation of the cells. Transgenic mice with ectopic expression of norrin show more bromodeoxyuridine-labeled retinal progenitor cells at embryonic day 14.5 and thicker retinas at postnatal life than wild-type littermates, indicating a putative direct neurotrophic effect of norrin. These data provide direct evidence that norrin induces growth of ocular capillaries and that pharmacologic modulation of norrin might be used for treatment of the vascular abnormalities associated with Norrie disease or other vascular disorders of the retina.

Tapered monocapillary-optics for point source applications

DOEpatents

Hirsch, Gregory

2000-01-01

A glass or metal wire is precisely etched to form the paraboloidal or ellipsoidal shape of the final desired capillary optic. This shape is created by carefully controlling the withdrawal speed of the wire from an etchant bath. In the case of a complete ellipsoidal capillary, the etching operation is performed twice in opposite directions on adjacent wire segments. The etched wire undergoes a subsequent operation to create an extremely smooth surface. This surface is coated with a layer of material which is selected to maximize the reflectivity of the radiation. This reflective surface may be a single layer for wideband reflectivity, or a multilayer coating for optimizing the reflectivity in a narrower wavelength interval. The coated wire is built up with a reinforcing layer, typically by a plating operation. The initial wire is removed by either an etching procedure or mechanical force. Prior to removing the wire, the capillary is typically bonded to a support substrate. One option for attaching the wire to the substrate produces a monolithic structure by essentially burying it under a layer of plating which covers both the wire and the substrate. The capillary optic is used for efficiently collecting and redirecting the divergent radiation from a source which could be the anode of an x-ray tube, a plasma source, the fluorescent radiation from an electron microprobe, or some other source of radiation.

The CE way of thinking: "all is relative!".

PubMed

Schmitt-Kopplin, Philippe; Fekete, Agnes

2008-01-01

Over the last two decades, the development of capillary electrophoresis (CE) instruments has lead to systems with programmable samplers, separation columns, separation buffers, and detection devices comparable visually in many aspects to the setup of classical chromatography. Two characteristics make CE essentially different from chromatography and are the basis of the CE way of thinking: first is the injection type and the liquid flow within the capillary. When the injection is made hydrodynamically (such as in most of the applications found in the literature), the injected volumes are directly dependent on the type and size of the separation capillary. The second characteristic is that in CE, buffer velocity is not pressure-driven, as in liquid chromatography, but is electrokinetically governed by the quality of the capillary surface (separation buffer dependent surface charge) inducing an electroosmotic flow (EOF). The EOF undergoes small variations and is not necessarily identical from one separation or day to the other. The direct consequence is that the migration time of the analytes apparently nonreproducible, although the velocity of the ions is the same. The effective mobility (field strength normalized velocity) of the ions is a possible parameterization from acquired time-scale to effective mobility-scale electropherograms leading to a reproducible visualization and better quantification with a direct relation to structural characters of the analytes (i.e., charge and size; see Chapter 23).

The Capillary Flow Experiments Aboard the International Space Station: Increments 9-15

NASA Technical Reports Server (NTRS)

Jenson, Ryan M.; Weislogel, Mark M.; Tavan, Noel T.; Chen, Yongkang; Semerjian, Ben; Bunnell, Charles T.; Collicott, Steven H.; Klatte, Jorg; dreyer, Michael E.

2009-01-01

This report provides a summary of the experimental, analytical, and numerical results of the Capillary Flow Experiment (CFE) performed aboard the International Space Station (ISS). The experiments were conducted in space beginning with Increment 9 through Increment 16, beginning August 2004 and ending December 2007. Both primary and extra science experiments were conducted during 19 operations performed by 7 astronauts including: M. Fincke, W. McArthur, J. Williams, S. Williams, M. Lopez-Alegria, C. Anderson, and P. Whitson. CFE consists of 6 approximately 1 to 2 kg handheld experiment units designed to investigate a selection of capillary phenomena of fundamental and applied importance, such as large length scale contact line dynamics (CFE-Contact Line), critical wetting in discontinuous structures (CFE-Vane Gap), and capillary flows and passive phase separations in complex containers (CFE-Interior Corner Flow). Highly quantitative video from the simply performed flight experiments provide data helpful in benchmarking numerical methods, confirming theoretical models, and guiding new model development. In an extensive executive summary, a brief history of the experiment is reviewed before introducing the science investigated. A selection of experimental results and comparisons with both analytic and numerical predictions is given. The subsequent chapters provide additional details of the experimental and analytical methods developed and employed. These include current presentations of the state of the data reduction which we anticipate will continue throughout the year and culminate in several more publications. An extensive appendix is used to provide support material such as an experiment history, dissemination items to date (CFE publication, etc.), detailed design drawings, and crew procedures. Despite the simple nature of the experiments and procedures, many of the experimental results may be practically employed to enhance the design of spacecraft engineering systems involving capillary interface dynamics.

The microvascular and morphostructural changes of nails in psoriatic patients with nail disease; a link between ultrasound and videocapillaroscopy findings in the nailfold.

PubMed

Bakirci Ureyen, Sibel; Kara, Rabia Oztas; Erturk, Zeynep; Yaldiz, Mahizer

2018-05-02

The objective of this study is to evaluate the link between nail fold vessel resistive index (NVRI) measured by ultrasound (US) and capillary loops diameters measured using nailfold videocapillarascopy (NVC), and to assess the morphological appearance of the nail bed in patients with psoriatic nail disease (PND) as compared with healthy controls (HCs). This study was conducted in patients with PND and HCs. General demographic data were collected and clinical assessments were performed for all subjects. The nail plate thickness (NPT) was measured on gray scale using US. The NVRI was measured using color Doppler (CD) US. The measurements of the apical, arterial, venous limb diameters and morpho-structural changes (tortuous, cross-linked capillaries) were assessed using NVC. Thirty-four patients with PND and 15 HCs were enrolled in this study. The two groups were matched for age and body mass index (BMI). Patients with PND had higher NPT and NVRI in comparison with HCs [(20 (17-23) vs 14 (14-15), p<0.001), (0.55 (0.51-0.61) vs 0.43 (0.38-0.49), p<0.001), respectively]. A higher proportion of patients with PND had tortuous capillaries than HCs (62% and 20% respectively, p=0.005). The mean NVRI was higher in patients with PND who had tortuous capillaries than patients who did not have tortuous capillaries (0.58 (0.7) and 0.52 (0.09), respectively p=0.033). Microvascular changes can be detected easily using non-invasive methods such as US and NVC. These methods can provide an objective data to better assess PND.

Altered Blood-Brain Barrier Permeability in Patients With Systemic Lupus Erythematosus: A Novel Imaging Approach.

PubMed

Gulati, Gaurav; Jones, Jordan T; Lee, Gregory; Altaye, Mekibib; Beebe, Dean W; Meyers-Eaton, Jamie; Wiley, Kasha; Brunner, Hermine I; DiFrancesco, Mark W

2017-02-01

To evaluate a safe, noninvasive magnetic resonance imaging (MRI) method to measure regional blood-brain barrier integrity and investigate its relationship with neurocognitive function and regional gray matter volume in juvenile-onset systemic lupus erythematosus (SLE). In this cross-sectional, case-control study, capillary permeability was measured as a marker of blood-brain barrier integrity in juvenile SLE patients and matched healthy controls, using a combination of arterial spin labeling and diffusion-weighted brain MRI. Regional gray matter volume was measured by voxel-based morphometry. Correlation analysis was done to investigate the relationship between regional capillary permeability and regional gray matter volume. Formal neurocognitive testing was completed (measuring attention, visuoconstructional ability, working memory, and psychomotor speed), and scores were regressed against regional blood-brain barrier integrity among juvenile SLE patients. Formal cognitive testing confirmed normal cognitive ability in all juvenile SLE subjects (n = 11) included in the analysis. Regional capillary permeability was negatively associated (P = 0.026) with neurocognitive performance concerning psychomotor speed in the juvenile SLE cohort. Compared with controls (n = 11), juvenile SLE patients had significantly greater capillary permeability involving Brodmann's areas 19, 28, 36, and 37 and caudate structures (P < 0.05 for all). There is imaging evidence of increased regional capillary permeability in juvenile SLE patients with normal cognitive performance using a novel noninvasive MRI technique. These blood-brain barrier outcomes appear consistent with functional neuronal network alterations and gray matter volume loss previously observed in juvenile SLE patients with overt neurocognitive deficits, supporting the notion that blood-brain barrier integrity loss precedes the loss of cognitive ability in juvenile SLE. Longitudinal studies are needed to confirm the findings of this pilot study. © 2016, American College of Rheumatology.

High-Throughput Genetic Analysis and Combinatorial Chiral Separations Based on Capillary Electrophoresis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhong, Wenwan

2003-01-01

Capillary electrophoresis (CE) offers many advantages over conventional analytical methods, such as speed, simplicity, high resolution, low cost, and small sample consumption, especially for the separation of enantiomers. However, chiral method developments still can be time consuming and tedious. They designed a comprehensive enantioseparation protocol employing neutral and sulfated cyclodextrins as chiral selectors for common basic, neutral, and acidic compounds with a 96-capillary array system. By using only four judiciously chosen separation buffers, successful enantioseparations were achieved for 49 out of 54 test compounds spanning a large variety of pKs and structures. Therefore, unknown compounds can be screened in thismore » manner to identify optimal enantioselective conditions in just one rn. In addition to superior separation efficiency for small molecules, CE is also the most powerful technique for DNA separations. Using the same multiplexed capillary system with UV absorption detection, the sequence of a short DNA template can be acquired without any dye-labels. Two internal standards were utilized to adjust the migration time variations among capillaries, so that the four electropherograms for the A, T, C, G Sanger reactions can be aligned and base calling can be completed with a high level of confidence. the CE separation of DNA can be applied to study differential gene expression as well. Combined with pattern recognition techniques, small variations among electropherograms obtained by the separation of cDNA fragments produced from the total RNA samples of different human tissues can be revealed. These variations reflect the differences in total RNA expression among tissues. Thus, this Ce-based approach can serve as an alternative to the DNA array techniques in gene expression analysis.« less

Pivotal debates and controversies on the structure and function of the avian respiratory system: setting the record straight.

PubMed

Maina, John N

2017-08-01

Among the extant air-breathing vertebrates, the avian respiratory system is structurally the most complex and functionally the most efficient gas exchanger. Having been investigated for over four centuries, some aspects of its biology have been extremely challenging and highly contentious and others still remain unresolved. Here, while assessing the most recent findings, four notable aspects of the structure and function of the avian respiratory system are examined critically to highlight the questions, speculations, controversies and debates that have arisen from past research. The innovative techniques and experiments that were performed to answer particular research questions are emphasised. The features that are outlined here concern the arrangement of the airways, the path followed by the inspired air, structural features of the lung and the air and blood capillaries, and the level of cellular defence in the avian respiratory system. Hitherto, based on association with the proven efficiency of naturally evolved and human-made counter-current exchange systems rather than on definite experimental evidence, a counter-current gas exchange system was suggested to exist in the avian respiratory system and was used to explain its exceptional efficiency. However, by means of an elegant experiment in which the direction of the air-flow in the lung was reversed, a cross-current system was shown to be in operation instead. Studies of the arrangement of the airways and the blood vessels corroborated the existence of a cross-current system in the avian lung. While the avian respiratory system is ventilated tidally, like most other invaginated gas exchangers, the lung, specifically the paleopulmonic parabronchi, is ventilated unidirectionally and continuously in a caudocranial (back-to-front) direction by synchronized actions of the air sacs. The path followed by the inspired air in the lung-air sac system is now known to be controlled by a mechanism of aerodynamic valving and not by anatomical valves or sphincters, as was previously supposed. The structural strength of the air and blood capillaries is derived from: the interdependence between the air and blood capillaries; a tethering effect between the closely entwined respiratory units; the presence of epithelial-epithelial cell connections (retinacula or cross-bridges) that join the blood capillaries while separating the air capillaries; the abundance and intricate arrangement of the connective tissue elements, i.e. collagen, elastin, and smooth muscle fibres; the presence of type-IV collagen, especially in the basement membranes of the blood-gas barrier and the epithelial-epithelial cell connections; and a putative tensegrity state in the lung. Notwithstanding the paucity of free surface pulmonary macrophages, the respiratory surface of the avian lung is well protected from pathogens and particulates by an assortment of highly efficient phagocytic cells. In commercial poultry production, instead of weak pulmonary cellular defence, stressful husbandry practices such as overcrowding, force-feeding, and intense genetic manipulation for rapid weight gain and egg production may account for the reported susceptibility of birds to aerosol-transmitted diseases. © 2016 Cambridge Philosophical Society.

Fine structure transitions in Fe XIV

NASA Astrophysics Data System (ADS)

Nahar, Sultana N.

2013-07-01

Results are reported for Fe XIV energy levels and transitions obtained from the ab initio relativistic Breit-Pauli R-matrix (BPRM) method. BPRM method developed under the Iron Project is capable of calculating very large number of fine structure energy levels and corresponding transitions. However, unlike in the atomic structure calculations, where levels are identified spectroscopically based on the leading percentage contributions of configurations, BPRM is incapable of such identification of the levels and hence the transitions. The main reason for it is that the percentage contributions can not be determined exactly from the large number of channels in the R-matrix space. The present report describes an identification method that uses considerations of quantum defects of channels, contributions of channel from outer regions, Hund's rule, and angular momenta algebra for addition and completeness of fine structure components. The present calculations are carried out using a close coupling wave function expansion that included 26 core excitations from configurations 2s22p63s2, 2s22p63s3p,2s22p63p2,2s22p63s3d, and 2s22p63p3d. A total of 1002 fine structure levels with n ⩽ 10, l⩽9, and 0.5 ⩽J⩽ 9.5 with even and odd parities and the corresponding 130,520 electric dipole allowed (E1) fine structure transitions, a most complete set for astrophysical modelings of spectral analysis and opacities, is presented. Large number of new energy levels are found and identified. The energies agree very well, mostly in less than 1% with the highest being 1.9%, with the 68 observed fine structure levels. While the high lying levels may have some uncertainty, an overall accuracy of energy levels should be within 10%. BPRM transitions have been benchmarked with the existing most accurate calculated transition probabilities with very good agreement for most cases. Based on the accuracy of the method and comparisons, most of the transitions can be rated with A (⩽10%) to C (⩽30%).

Melt fracture revisited

DOE Office of Scientific and Technical Information (OSTI.GOV)

Greenberg, J. M.

2003-07-16

In a previous paper the author and Demay advanced a model to explain the melt fracture instability observed when molten linear polymer melts are extruded in a capillary rheometer operating under the controlled condition that the inlet flow rate was held constant. The model postulated that the melts were a slightly compressible viscous fluid and allowed for slipping of the melt at the wall. The novel feature of that model was the use of an empirical switch law which governed the amount of wall slip. The model successfully accounted for the oscillatory behavior of the exit flow rate, typically referredmore » to as the melt fracture instability, but did not simultaneously yield the fine scale spatial oscillations in the melt typically referred to as shark skin. In this note a new model is advanced which simultaneously explains the melt fracture instability and shark skin phenomena. The model postulates that the polymer is a slightly compressible linearly viscous fluid but assumes no slip boundary conditions at the capillary wall. In simple shear the shear stress {tau}and strain rate d are assumed to be related by d = F{tau} where F ranges between F{sub 2} and F{sub 1} > F{sub 2}. A strain rate dependent yield function is introduced and this function governs whether F evolves towards F{sub 2} or F{sub 1}. This model accounts for the empirical observation that at high shears polymers align and slide more easily than at low shears and explains both the melt fracture and shark skin phenomena.« less

Capillary Optics Based X-Ray Micro-Imaging Elemental Analysis

NASA Astrophysics Data System (ADS)

Hampai, D.; Dabagov, S. B.; Cappuccio, G.; Longoni, A.; Frizzi, T.; Cibin, G.

2010-04-01

A rapidly developed during the last few years micro-X-ray fluorescence spectrometry (μXRF) is a promising multi-elemental technique for non-destructive analysis. Typically it is rather hard to perform laboratory μXRF analysis because of the difficulty of producing an original small-size X-ray beam as well as its focusing. Recently developed for X-ray beam focusing polycapillary optics offers laboratory X-ray micro probes. The combination of polycapillary lens and fine-focused micro X-ray tube can provide high intensity radiation flux on a sample that is necessary in order to perform the elemental analysis. In comparison to a pinhole, an optimized "X-ray source-op tics" system can result in radiation density gain of more than 3 orders by the value. The most advanced way to get that result is to use the confocal configuration based on two X-ray lenses, one for the fluorescence excitation and the other for the detection of secondary emission from a sample studied. In case of X-ray capillary microfocusing a μXRF instrument designed in the confocal scheme allows us to obtain a 3D elemental mapping. In this work we will show preliminary results obtained with our prototype, a portable X-ray microscope for X-ray both imaging and fluorescence analysis; it enables μXRF elemental mapping simultaneously with X-ray imaging. A prototype of compact XRF spectrometer with a spatial resolution less than 100 μm has been designed.

MEMBRANE POTENTIAL OF THE SQUID GIANT AXON DURING CURRENT FLOW

PubMed Central

Cole, Kenneth S.; Curtis, Howard J.

1941-01-01

The squid giant axon was placed in a shallow narrow trough and current was sent in at two electrodes in opposite sides of the trough and out at a third electrode several centimeters away. The potential difference across the membrane was measured between an inside fine capillary electrode with its tip in the axoplasm between the pair of polarizing electrodes, and an outside capillary electrode with its tip flush with the surface of one polarizing electrode. The initial transient was roughly exponential at the anode make and damped oscillatory at the sub-threshold cathode make with the action potential arising from the first maximum when threshold was reached. The constant change of membrane potential, after the initial transient, was measured as a function of the total polarizing current and from these data the membrane potential is obtained as a function of the membrane current density. The absolute value of the resting membrane resistance approached at low polarizing currents is about 23 ohm cm.2. This low value is considered to be a result of the puncture of the axon. The membrane was found to be an excellent rectifier with a ratio of about one hundred between the high resistance at the anode and the low resistance at the cathode for the current range investigated. On the assumption that the membrane conductance is a measure of its ion permeability, these experiments show an increase of ion permeability under a cathode and a decrease under an anode. PMID:19873234

An ultrasensitive electrochemiluminescence sensor based on reduced graphene oxide-copper sulfide composite coupled with capillary electrophoresis for determination of amlodipine besylate in mice plasma.

PubMed

Wei, Yanfen; Wang, Hao; Sun, Shuangjiao; Tang, Lifu; Cao, Yupin; Deng, Biyang

2016-12-15

A new electrochemiluminescence (ECL) sensor based on reduced graphene oxide-copper sulfide (rGO-CuS) composite coupled with capillary electrophoresis (CE) was constructed for the ultrasensitive detection of amlodipine besylate (AML) for the first time. In this work, rGO-CuS composite was synthesized by one-pot hydrothermal method and used for electrode modification. The electrochemical and ECL behaviors of the sensor were investigated. More than 5-fold enhance in ECL intensity was observed after modified with rGO-CuS composite. The results can be ascribed to the presence of rGO-CuS composite on the electrode surface that facilitates the electron transfer rate between the electroactive center of Ru(bpy)3(2+) and the electrode. The ECL sensor was coupled with CE to improve the selectivity and the CE-ECL parameters that affect separation and detection were optimized. Under the optimum conditions, the linear ranges for AML was 0.008-5.0μg/mL with a detection limit of 2.8ng/mL (S/N=3). The method displayed the advantages of high sensitivity, good selectivity, wide linear range, low detection limit and fine reproducibility, and was used to analyze AML in mice plasma with a satisfactory result, which holds a great potential in the field of pharmaceutical analysis. Copyright © 2016 Elsevier B.V. All rights reserved.

Size structure of marine soft-bottom macrobenthic communities across natural habitat gradients: implications for productivity and ecosystem function.

PubMed

Macdonald, Tara A; Burd, Brenda J; van Roodselaar, Albert

2012-01-01

Size distributions of biotic assemblages are important modifiers of productivity and function in marine sediments. We investigated the distribution of proportional organic biomass among logarithmic size classes (2(-6)J to 2(16)J) in the soft-bottom macrofaunal communities of the Strait of Georgia, Salish Sea on the west coast of Canada. The study examines how size structure is influenced by 3 fundamental habitat descriptors: depth, sediment percent fines, and organic flux (modified by quality). These habitat variables are uncorrelated in this hydrographically diverse area, thus we examine their effects in combination and separately. Cluster analyses and cumulative biomass size spectra reveal clear and significant responses to each separate habitat variable. When combined, habitat factors result in three distinct assemblages: (1) communities with a high proportion of biomass in small organisms, typical of shallow areas (<10 m) with coarse sediments (<10% fines) and low accumulation of organic material (<3.0 gC/m(2)/yr/δ(15)N); (2) communities with high proportion of biomass in the largest organisms found in the Strait, typical of deep, fine sediments with high modified organic flux (>3 g C/m(2)/yr/δ(15)N) from the Fraser River; and (3) communities with biomass dominated by moderately large organisms, but lacking the smallest and largest size classes, typical of deep, fine sediments experiencing low modified organic flux (<3.0 gC/m(2)/yr/δ(15)N). The remaining assemblages had intermediate habitat types and size structures. Sediment percent fines and flux appear to elicit threshold responses in size structure, whereas depth has the most linear influence on community size structure. The ecological implications of size structure in the Strait of Georgia relative to environmental conditions, secondary production and sediment bioturbation are discussed.

Size Structure of Marine Soft-Bottom Macrobenthic Communities across Natural Habitat Gradients: Implications for Productivity and Ecosystem Function

PubMed Central

Macdonald, Tara A.; Burd, Brenda J.; van Roodselaar, Albert

2012-01-01

Size distributions of biotic assemblages are important modifiers of productivity and function in marine sediments. We investigated the distribution of proportional organic biomass among logarithmic size classes (2−6J to 216J) in the soft-bottom macrofaunal communities of the Strait of Georgia, Salish Sea on the west coast of Canada. The study examines how size structure is influenced by 3 fundamental habitat descriptors: depth, sediment percent fines, and organic flux (modified by quality). These habitat variables are uncorrelated in this hydrographically diverse area, thus we examine their effects in combination and separately. Cluster analyses and cumulative biomass size spectra reveal clear and significant responses to each separate habitat variable. When combined, habitat factors result in three distinct assemblages: (1) communities with a high proportion of biomass in small organisms, typical of shallow areas (<10 m) with coarse sediments (<10% fines) and low accumulation of organic material (<3.0 gC/m2/yr/δ15N); (2) communities with high proportion of biomass in the largest organisms found in the Strait, typical of deep, fine sediments with high modified organic flux (>3 g C/m2/yr/δ15N) from the Fraser River; and (3) communities with biomass dominated by moderately large organisms, but lacking the smallest and largest size classes, typical of deep, fine sediments experiencing low modified organic flux (<3.0 gC/m2/yr/δ15N). The remaining assemblages had intermediate habitat types and size structures. Sediment percent fines and flux appear to elicit threshold responses in size structure, whereas depth has the most linear influence on community size structure. The ecological implications of size structure in the Strait of Georgia relative to environmental conditions, secondary production and sediment bioturbation are discussed. PMID:22911694

MOLECULAR CHARACTERIZATION OF MICROBIAL COMMUNITIES IN A JP-4 FUEL CONTAMINATED SOIL

EPA Science Inventory

In this study, lipid biomarker characterization of the bacterial and eukaryotic communities was combined with PCR-DGGE analysis of the eubacterial community to evaluate correlation between JP-4 fuel concentration and community structure shifts. Vadose, capillary fringe and satur...

Ion guiding in macro-size insulating capillaries: straight, tapered, and curved shapes

NASA Astrophysics Data System (ADS)

Kojima, Takao M.

2018-02-01

When keV energy ions are injected into a tilted insulating capillary, a certain fraction of the injected ions are transported through the tilt angle of the capillary. This ion guiding phenomenon is considered to be caused by a self-organizing charge distribution, where the inner wall of the capillary becomes charged by initial incoming ions. The charge distribution, which is formed, can guide following ions toward the exit of the capillary. Since the initial discovery of this effect, studies of ion guiding by insulating capillaries have been extended to various materials, and different sizes and shapes of capillaries. In recent years, some investigations of the guiding effect of macro-size curved capillaries have also been reported. In this review, relevant studies in a history of ion guiding in curved capillaries are discussed and future directions in this field are considered.

High-speed video capillaroscopy method for imaging and evaluation of moving red blood cells

NASA Astrophysics Data System (ADS)

Gurov, Igor; Volkov, Mikhail; Margaryants, Nikita; Pimenov, Aleksei; Potemkin, Andrey

2018-05-01

The video capillaroscopy system with high image recording rate to resolve moving red blood cells with velocity up to 5 mm/s into a capillary is considered. Proposed procedures of the recorded video sequence processing allow evaluating spatial capillary area, capillary diameter and central line with high accuracy and reliability independently on properties of individual capillary. Two-dimensional inter frame procedure is applied to find lateral shift of neighbor images in the blood flow area with moving red blood cells and to measure directly the blood flow velocity along a capillary central line. The developed method opens new opportunities for biomedical diagnostics, particularly, due to long-time continuous monitoring of red blood cells velocity into capillary. Spatio-temporal representation of capillary blood flow is considered. Experimental results of direct measurement of blood flow velocity into separate capillary as well as capillary net are presented and discussed.

Automated Parallel Capillary Electrophoretic System

DOEpatents

Li, Qingbo; Kane, Thomas E.; Liu, Changsheng; Sonnenschein, Bernard; Sharer, Michael V.; Kernan, John R.

2000-02-22

An automated electrophoretic system is disclosed. The system employs a capillary cartridge having a plurality of capillary tubes. The cartridge has a first array of capillary ends projecting from one side of a plate. The first array of capillary ends are spaced apart in substantially the same manner as the wells of a microtitre tray of standard size. This allows one to simultaneously perform capillary electrophoresis on samples present in each of the wells of the tray. The system includes a stacked, dual carousel arrangement to eliminate cross-contamination resulting from reuse of the same buffer tray on consecutive executions from electrophoresis. The system also has a gel delivery module containing a gel syringe/a stepper motor or a high pressure chamber with a pump to quickly and uniformly deliver gel through the capillary tubes. The system further includes a multi-wavelength beam generator to generate a laser beam which produces a beam with a wide range of wavelengths. An off-line capillary reconditioner thoroughly cleans a capillary cartridge to enable simultaneous execution of electrophoresis with another capillary cartridge. The streamlined nature of the off-line capillary reconditioner offers the advantage of increased system throughput with a minimal increase in system cost.

Fluid Delivery System For Capillary Electrophoretic Applications.

DOEpatents

Li, Qingbo; Liu, Changsheng; Kane, Thomas E.; Kernan, John R.; Sonnenschein, Bernard; Sharer, Michael V.

2002-04-23

An automated electrophoretic system is disclosed. The system employs a capillary cartridge having a plurality of capillary tubes. The cartridge has a first array of capillary ends projecting from one side of a plate. The first array of capillary ends are spaced apart in substantially the same manner as the wells of a microtitre tray of standard size. This allows one to simultaneously perform capillary electrophoresis on samples present in each of the wells of the tray. The system includes a stacked, dual carrousel arrangement to eliminate cross-contamination resulting from reuse of the same buffer tray on consecutive executions from electrophoresis. The system also has a gel delivery module containing a gel syringe/a stepper motor or a high pressure chamber with a pump to quickly and uniformly deliver gel through the capillary tubes. The system further includes a multi-wavelength beam generator to generate a laser beam which produces a beam with a wide range of wavelengths. An off-line capillary reconditioner thoroughly cleans a capillary cartridge to enable simultaneous execution of electrophoresis with another capillary cartridge. The streamlined nature of the off-line capillary reconditioner offers the advantage of increased system throughput with a minimal increase in system cost.

XFAS SPECTROSCOPY ANALYSIS OF SELECTED HAP ELEMENTS IN FINE PM DERIVED FROM COAL COMBUSTION: JOURNAL ARTICLE

EPA Science Inventory

NRMRL-RTP-P-646 Shoji, T., Huggins, F.E., Huffman, G.P., Linak*, W.P., and Miller*, C.A. XFAS Spectroscopy Analysis of Selected HAP Elements in Fine PM Derived from Coal Combustion. Energy and Fuels 16 (2): (2002). 11/30/2001 X-ray absorption fine structure (XAFS) spectroscop...