Impaired skin capillary recruitment in essential hypertension is caused by both functional and structural capillary rarefaction

NARCIS (Netherlands)

Serne, EH; Gans, ROB; ter Maaten, JC; Tangelder, GJ; Donker, AJM; Stehouwer, CDA

Capillary rarefaction occurs in many tissues in patients with essential hypertension and may contribute to an increased vascular resistance and impaired muscle metabolism. Rarefaction may be caused by a structural (anatomic) absence of capillaries, functional nonperfusion, or both. The aim of this

Modeling capillary bridge dynamics and crack healing between surfaces of nanoscale roughness

Science.gov (United States)

Soylemez, Emrecan; de Boer, Maarten P.

2017-12-01

Capillary bridge formation between adjacent surfaces in humid environments is a ubiquitous phenomenon. It strongly influences tribological performance with respect to adhesion, friction and wear. Only a few studies, however, assess effects due to capillary dynamics. Here we focus on how capillary bridge evolution influences crack healing rates. Experimental results indicated a logarithmic decrease in average crack healing velocity as the energy release rate increases. Our objective is to model that trend. We assume that capillary dynamics involve two mechanisms: capillary bridge growth and subsequently nucleation followed by growth. We show that by incorporating interface roughness details and the presence of an adsorbed water layer, the behavior of capillary force dynamics can be understood quantitatively. We identify three important regimes that control the healing process, namely bridge growth, combined bridge growth and nucleation, and finally bridge nucleation. To fully capture the results, however, the theoretical model for nucleation time required an empirical modification. Our model enables significant insight into capillary bridge dynamics, with a goal of attaining a predictive capability for this important microelectromechanical systems (MEMS) reliability failure mechanism.

Soft x-ray lasing in a capillary discharge

International Nuclear Information System (INIS)

Lee, Tong-Nyong; Shin, Hyun-Joon; Kim, Dong-Eon

1995-01-01

Soft x-ray lasing in the C VI Balmer α transition is observed in a capillary discharge. The capillary is made of polyethylene with a bore diameter of 1.2 mm. Plasma radiation from the discharge is analyzed using a toroidal mirror and a two-meter grazing-incidence spectrograph-monochromator. The electron temperatures are measured at both the axial and the peripheral region close to the capillary wall, using space-resolved spectra. A comparison of the branching ratio in the hot (axial) and the cool (peripheral) plasma regions indicates that there is a large population inversion between n=3 and 2 states of C 5+ ions in the cool (Te∼13 eV) region of the capillary plasma. Relative line intensities of the C VI Hα and a number of non-lasing lines are compared in this cool region as a function of capillary length. The C VI Hα line intensity increases exponentially whereas those of non-lasing transitions increase linearly with an increase of the capillary length. The gain coefficient thus measured indicates 2.8 cm -1 . The lasing line intensity does not seem to increase exponentially beyond a capillary length of 16 mm and the gain-length product, gL, obtained here is 3.9, which is a typical value one would expect for a recombination soft x-ray laser. The photoelectric signals of the lasing line indicate that the lasing takes place about 40 ns after the current peak in the first half cycle of the capillary discharge, with a lasing pulse width of 60 ns in FWHM

Ion guiding and losses in insulator capillaries

International Nuclear Information System (INIS)

Juhasz, Z.; Sulik, B.; Vikor, Gy.; Biri, S.; Fekete, E.; Ivan, I.; Gall, F.; Toekesi, K.; Matefi-Tempfli, S.; Matefi-Tempfli, M.

2007-01-01

Complete text of publication follows. Not long ago it was discovered that insulating capillaries can guide slow ions, so that the ions avoid close contact with the capillary walls and preserve their initial charge state. This phenomenon did not only give a new puzzle for theoreticians but opened the way for new possible applications where ions are manipulated (deflected, focused and directed to different patterns on the irradiated media) with small capillary devices. The most important question for such applications is how large fraction of the ions can be guided to the desired direction. It is already known that the ion guiding is due to the charging up of the inner capillary walls by earlier ion impact events. In tilted capillaries one side of the capillary walls charges up. This deflects the later arriving ions, so that some of them pass through the capillaries nearly parallel with respect to their axes. The angle where the transmission drops to 1/e of the direct transmission at 0 deg is the guiding angle, which characterize the guiding ability. At 0 deg the ideal 100 percent transmission for the ions, which enter the capillaries, is reduced due to the mirror charge attraction and geometrical imperfections. These losses appear in the transmission for tilted capillaries with similar magnitude, since after the deflection region, which usually restricted to the close surroundings of the capillary openings, the guided ions pass through the rest of the capillaries as in non-tilted samples. In our experimental studies with Al 2 O 3 capillaries we found that around 90 percent of the incoming ions are lost. To understand these significant losses, the effects of the mirror charge attraction and geometrical imperfections have been calculated classically. The mirror charge potential was taken from.The model of the capillaries used in the calculations can be seen in Figure 1. The calculations have shown that the effects of mirror charge attraction and the angular

Myocardial capillary permeability after regional ischemia and reperfusion in the in vivo canine heart. Effect of superoxide dismutase

DEFF Research Database (Denmark)

Svendsen, Jesper Hastrup; Bjerrum, P J; Haunsø, S

1991-01-01

coronary artery followed by 1 hour of reperfusion. Myocardial plasma flow rate and capillary extraction of chromium 51-labeled EDTA or technetium 99m-labeled diethylenetriaminepentaacetic acid were measured by the single-injection, residue-detection method before ischemia and 5 and 60 minutes after...... fibrillation in contrast to none in the superoxide dismutase group. Before ischemia, plasma flow rate, myocardial capillary extraction fraction, and PS values were similar in the two groups. Five minutes after the start of reperfusion, plasma flow rate increased significantly (p less than 0.01) in both groups....... In the control group, capillary extraction fraction increased by 12% (p = NS) in spite of the higher plasma flow; these increases in capillary extraction fraction and plasma flow induced a 69% increase in PS (p less than 0.01). In the superoxide dismutase-treated group, capillary extraction fraction decreased...

Early capillary flux homogenization in response to neural activation.

Science.gov (United States)

Lee, Jonghwan; Wu, Weicheng; Boas, David A

2016-02-01

This Brief Communication reports early homogenization of capillary network flow during somatosensory activation in the rat cerebral cortex. We used optical coherence tomography and statistical intensity variation analysis for tracing changes in the red blood cell flux over hundreds of capillaries nearly at the same time with 1-s resolution. We observed that while the mean capillary flux exhibited a typical increase during activation, the standard deviation of the capillary flux exhibited an early decrease that happened before the mean flux increase. This network-level data is consistent with the theoretical hypothesis that capillary flow homogenizes during activation to improve oxygen delivery. © The Author(s) 2015.

Prenatal hypoxia induces increased cardiac contractility on a background of decreased capillary density

Directory of Open Access Journals (Sweden)

Ousley Victoria

2009-01-01

Full Text Available Abstract Background Chronic hypoxia in utero (CHU is one of the most common insults to fetal development and may be associated with poor cardiac recovery from ischaemia-reperfusion injury, yet the effects on normal cardiac mechanical performance are poorly understood. Methods Pregnant female wistar rats were exposed to hypoxia (12% oxygen, balance nitrogen for days 10–20 of pregnancy. Pups were born into normal room air and weaned normally. At 10 weeks of age, hearts were excised under anaesthesia and underwent retrograde 'Langendorff' perfusion. Mechanical performance was measured at constant filling pressure (100 cm H2O with intraventricular balloon. Left ventricular free wall was dissected away and capillary density estimated following alkaline phosphatase staining. Expression of SERCA2a and Nitric Oxide Synthases (NOS proteins were estimated by immunoblotting. Results CHU significantly increased body mass (P in utero. Conclusion These data offer potential mechanisms for poor recovery following ischaemia, including decreased coronary flow reserve and impaired angiogenesis with subsequent detrimental effects of post-natal cardiac performance.

Two-dimensional capillary electrophoresis: capillary isoelectric focusing and capillary zone electrophoresis with laser-induced fluorescence detection

Science.gov (United States)

Dickerson, Jane A.; Ramsay, Lauren M.; Dada, Oluwatosin O.; Cermak, Nathan

2011-01-01

Capillary isoelectric focusing and capillary zone electrophoresis are coupled with laser-induced fluorescence detection to create an ultrasensitive two-dimensional separation method for proteins. In this method, two capillaries are joined through a buffer filled interface. Separate power supplies control the potential at the injection end of the first capillary and at the interface; the detector is held at ground potential. Proteins are labeled with the fluorogenic reagent Chromeo P503, which preserves the isoelectric point of the labeled protein. The labeled proteins were mixed with ampholytes and injected into the first dimension capillary. A focusing step was performed with the injection end of the capillary at high pH and the interface at low pH. To mobilize components, the interface was filled with a high pH buffer, which was compatible with the second dimension separation. A fraction was transferred to the second dimension capillary for separation. The process of fraction transfer and second dimension separation was repeated two dozen times. The separation produced a spot capacity of 125. PMID:20603830

Thromboxane plays a role in postprandial jejunal oxygen uptake and capillary exchange.

Science.gov (United States)

Alemayehu, A; Chou, C C

1990-09-01

The effects of a thromboxane A2 (TxA2)-endoperoxide receptor antagonist, SQ 29548, on jejunal blood flow, oxygen uptake, and capillary filtration coefficient (Kfc) were determined in anesthetized dogs under resting conditions and during the presence of predigested food in the jejunal lumen in three series of experiments. In series 1, 2.0 micrograms intra-arterial administration of SQ 29548 was found to abolish completely the vasoconstrictor action of graded doses (0.05-2.0 micrograms) of intra-arterial injection of a TxA2-endoperoxide analogue, U44069. SQ 29548 (2.0 micrograms ia) per se did not significantly alter resting jejunal blood flow, oxygen uptake, capillary pressure, or Kfc. Before SQ 29548, placement of food plus bile into the jejunal lumen increased blood flow +42 +/- 9%, oxygen uptake +28 +/- 7%, and Kfc +24 +/- 6%. After SQ 29548, the food placement increased blood flow +37 +/- 8%, oxygen uptake +52 +/- 11%, and Kfc +63 +/- 20%. The food-induced increases in oxygen uptake and Kfc after SQ 29548 were significantly greater than those induced before the blocking of TxA2-endoperoxide receptors by SQ 29548. Our study indicates that endogenous thromboxane does not play a role in regulating jejunal blood flow, capillary filtration, and oxygen uptake under resting conditions. However, it plays a role in limiting the food-induced increases in jejunal oxygen uptake and capillary exchange capacity without influencing the food-induced hyperemia.

Capillary Versus Aspiration Biopsy: Effect of Needle Size and Length on the Cytopathological Specimen Quality

International Nuclear Information System (INIS)

Hopper, Kenneth D.; Grenko, Ronald T.; Fisher, Alicia I.; TenHave, Thomas R.

1996-01-01

Purpose: To test the value of the nonaspiration, or capillary, biopsy technique by experimental comparison with the conventional fine-needle aspiration technique using various needle gauges and lengths. Methods: On fresh hepatic and renal tissue from five autopsies, multiple biopsy specimens were taken with 20, 22, and 23-gauge Chiba needles of 5, 10, 15, and 20-cm length, using the aspiration technique and the capillary technique. The resultant specimens were graded on the basis of a grading scheme by a cytopathologist who was blinded to the biopsy technique. Results: The capillary technique obtained less background blood or clot which could obscure diagnostic tissue, although not significantly different from the aspiration technique (p= 0.2). However, for the amount of cellular material obtained, retention of appropriate architecture, and mean score, the capillary technique performed statistically worse than aspiration biopsy (p < 0.01). In addition, with decreasing needle caliber (increasing needle gauge) and increasing length, the capillary biopsy was inferior to the aspiration biopsy. Conclusion: The capillary biopsy technique is inferior to the aspiration technique according to our study. When the capillary technique is to be applied, preference should be given to larger caliber, shorter needles

3D capillary valves for versatile capillary patterning of channel walls

NARCIS (Netherlands)

Papadimitriou, Vasileios; van den Berg, Albert; Eijkel, Jan C.T.

2016-01-01

We demonstrate passive capillary patterning of channel walls with a liquid in situ. Patterning is performed using a novel 3D capillary valve system combining three standard capillary stop valves. A range of different patterns is demonstrated in three channel walls. Capillary patterning was designed

Progression of Diabetic Capillary Occlusion: A Model.

Directory of Open Access Journals (Sweden)

Xiao Fu

2016-06-01

Full Text Available 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.

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

Science.gov (United States)

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 (Pgroup and middle group. In the small dose Kangxuan granule group, the opening number of capillary network of auricle decreased significantly (Pgroup, the large dose Kangxuan granule group could significantly increase the opening number of the auricle capillary network in mice (Pgroup could significantly increase the opening number of auricle capillary reticulum in mice (Pgroup 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 (Pblood flow in mice with microcirculation disorder.

Capillary density: An important parameter in nailfold capillaroscopy.

Science.gov (United States)

Emrani, Zahra; Karbalaie, Abdolamir; Fatemi, Alimohammad; Etehadtavakol, Mahnaz; Erlandsson, Björn-Erik

2017-01-01

Nailfold capillaroscopy is one of the various noninvasive bioengineering methods used to investigate skin microcirculation. It is an effective examination for assessing microvascular changes in the peripheral circulation; hence it has a significant role for the diagnosis of Systemic sclerosis with the classic changes of giant capillaries as well as the decline in capillary density with capillary dropout. The decline in capillary density is one of microangiopathic features existing in connective tissue disease. It is detectable with nailfold capillaroscopy. This parameter is assessed by applying quantitative measurement. In this article, we reviewed a common method for calculating the capillary density and the relation between the number of capillaries as well as the existence of digital ulcers, pulmonary arterial hypertension, autoantibodies, scleroderma patterns and different scoring system. Copyright © 2016 Elsevier Inc. All rights reserved.

Increased Water Retention in Polymer Electrolyte Membranes at Elevated Temperatures Assisted by Capillary Condensation

International Nuclear Information System (INIS)

Park, M.J.; Downing, K.H.; Jackson, A.; Gomez, E.D.; Minor, A.M.; Cookson, D.; Weber, A.Z.; Balsara, N.P.

2007-01-01

We establish a new systematic methodology for controlling the water retention of polymer electrolyte membranes. Block copolymer membranes comprising hydrophilic phases with widths ranging from 2 to 5 nm become wetter as the temperature of the surrounding air is increased at constant relative humidity. The widths of the moist hydrophilic phases were measured by cryogenic electron microscopy experiments performed on humid membranes. Simple calculations suggest that capillary condensation is important at these length scales. The correlation between moisture content and proton conductivity of the membranes is demonstrated.

Increased water retention in polymer electrolyte membranes at elevated temperatures assisted by capillary condensation.

Science.gov (United States)

Park, Moon Jeong; Downing, Kenneth H; Jackson, Andrew; Gomez, Enrique D; Minor, Andrew M; Cookson, David; Weber, Adam Z; Balsara, Nitash P

2007-11-01

We establish a new systematic methodology for controlling the water retention of polymer electrolyte membranes. Block copolymer membranes comprising hydrophilic phases with widths ranging from 2 to 5 nm become wetter as the temperature of the surrounding air is increased at constant relative humidity. The widths of the moist hydrophilic phases were measured by cryogenic electron microscopy experiments performed on humid membranes. Simple calculations suggest that capillary condensation is important at these length scales. The correlation between moisture content and proton conductivity of the membranes is demonstrated.

Capillary density and capillary-to-fibre ratio in vastus lateralis muscle of untrained and trained men.

Science.gov (United States)

Zoladz, J A; Semik, D; Zawadowska, B; Majerczak, J; Karasinski, J; Kolodziejski, L; Duda, K; Kilarski, W M

2005-01-01

Muscle fibre profile area (Af), volume density (Vv), capillary-to-fibre ratio (CF) and number of capillaries per fibre square millimetre (CD) were determined from needle biopsies of vastus lateralis of twenty-four male volunteers (mean +/- SD: age 25.4+/-5.8 years, height 178.6+/-5.5 cm, body mass 72.1+/-7.7 kg) of different training background. Seven subjects were untrained students (group A), nine were national and sub-national level endurance athletes (group B) with the background of 7.8+/-2.9 years of specialised training, and eight subjects were sprint-power athletes (group C) with 12.8+/-8.7 years of specialised training. Muscle biopsies of vastus lateralis were analysed histochemically for mATPase. Capillaries were visualized and counted using CD31 antibodies against endothelial cells. There were significant differences in the Vv of type I and type II muscle fibres in both trained groups, B (51.8%; 25.6%) and C (50.5%; 26.4%). However, in untrained group A that was treated as a reference group, the difference between Vv of type I and type II fibres was less prominent, nevertheless statistically significant (42.1%; 35.1%). There was also a significant difference in CF: 1.9 in group A and 2.1 in groups B and C. The number of capillaries per mm2 (CD) was 245 (group A), 308 (group B) and 325 (group C). Significant differences (Pski-jumping, volleyball, soccer and modern dance.

Capillary Interactions between a Probe Tip and a Nanoparticle

International Nuclear Information System (INIS)

Li-Ning, Sun; Le-Feng, Wang; Wei-Bin, Rong

2008-01-01

To understand capillary interactions between probe tips and nanoparticles under ambient conditions, a theoretical model of capillary forces between them is developed based on the geometric relations. It is found that the contribution of surface tension force to the total capillary force attains to similar order of magnitude as the capillary pressure force in many cases. It is also shown that the tip shape and the radial distance of the meniscus have great influence on the capillary force. The capillary force decreases with the increasing separation distances, and the variance of the contact angles may change the magnitudes of capillary forces several times at large radial distances. The applicability of the symmetric meniscus approximation is discussed. (condensed matter: structure, mechanical and thermal properties)

Minimized Capillary End Effect During CO2 Displacement in 2-D Micromodel by Manipulating Capillary Pressure at the Outlet Boundary in Lattice Boltzmann Method

Science.gov (United States)

Kang, Dong Hun; Yun, Tae Sup

2018-02-01

We propose a new outflow boundary condition to minimize the capillary end effect for a pore-scale CO2 displacement simulation. The Rothman-Keller lattice Boltzmann method with multi-relaxation time is implemented to manipulate a nonflat wall and inflow-outflow boundaries with physically acceptable fluid properties in 2-D microfluidic chip domain. Introducing a mean capillary pressure acting at CO2-water interface to the nonwetting fluid at the outlet effectively prevents CO2 injection pressure from suddenly dropping upon CO2 breakthrough such that the continuous CO2 invasion and the increase of CO2 saturation are allowed. This phenomenon becomes most pronounced at capillary number of logCa = -5.5, while capillary fingering and massive displacement of CO2 prevail at low and high capillary numbers, respectively. Simulations with different domain length in homogeneous and heterogeneous domains reveal that capillary pressure and CO2 saturation near the inlet are reproducible compared with those with a proposed boundary condition. The residual CO2 saturation uniquely follows the increasing tendency with increasing capillary number, corroborated by experimental evidences. The determination of the mean capillary pressure and its sensitivity are also discussed. The proposed boundary condition is commonly applicable to other pore-scale simulations to accurately capture the spatial distribution of nonwetting fluid and corresponding displacement ratio.

Slope wavenumber spectrum models of capillary and capillary-gravity waves

Institute of Scientific and Technical Information of China (English)

贾永君; 张杰; 王岩峰

2010-01-01

Capillary and capillary-gravity waves possess a random character, and the slope wavenumber spectra of them can be used to represent mean distributions of wave energy with respect to spatial scale of variability. But simple and practical models of the slope wavenumber spectra have not been put forward so far. In this article, we address the accurate definition of the slope wavenumber spectra of water surface capillary and capillary-gravity waves. By combining the existing slope wavenumber models and using th...

Evaluation of mast cells, eosinophils, blood capillaries in oral lichen planus and oral lichenoid mucositis.

Science.gov (United States)

Reddy, D Santhosh; Sivapathasundharam, B; Saraswathi, T R; SriRam, G

2012-01-01

Mast cells are granule containing secretory cells present in oral mucosal and connective tissue environment. Oral lichen planus and oral lichenoid lesions are commonly occurring oral diseases and have some similarity clinically and histologically. Both are characterized by an extensive sub epithelial infiltrate of T cells, together with mast cells, eosinophils and blood capillaries. In this study mast cell and eosinophil densities along with number of blood capillaries were studied to find out if they could aid in histopathological distinction between oral lichen planus and lichenoid mucositis. To enumerate mast cells and compare the status of Mast Cells (Intact or Degranulated) in Lichen planus, Lichenoid mucositis and normal buccal mucosa in tissue sections stained with Toluidine Blue, and also to enumerate Eosinophils and blood capillaries in tissue sections stained with H and E. The study group included 30 cases each of oral lichen planus and oral lichenoid mucositis. 10 cases of clinically normal oral buccal mucosa formed the control group. All the sections were stained with Toluidine blue and H and E separately. Histopathological analysis was done using binocular light microscope equipped with square ocular grid to standardize the field of evaluation. The result of the study showed. · Significant increase in number of mast cells in oral lichen planus and oral lichenoid mucositis compared to normal buccal mucosa. · Significant increase of intact mast cells suepithelially within the inflammatory cell infiltrate in oral lichen planus compared to oral lichenoid mucositis. · Significant increase of degranulated mast cells in oral lichenoid mucositis to oral lichen planus, and increase in number of eosinophil densities in oral lichenoid mucositis compared to oral lichen planus. · Significant increase in number of capillaries in oral lichenoid mucositis compared to oral lichen planus. The findings of increased number of intact mast cells sub epithelially in oral

Hierarchical capillary adhesion of microcantilevers or hairs

International Nuclear Information System (INIS)

Liu Jianlin; Feng Xiqiao; Xia Re; Zhao Hongping

2007-01-01

As a result of capillary forces, animal hairs, carbon nanotubes or nanowires of a periodically or randomly distributed array often assemble into hierarchical structures. In this paper, the energy method is adopted to analyse the capillary adhesion of microsized hairs, which are modelled as clamped microcantilevers wetted by liquids. The critical conditions for capillary adhesion of two hairs, three hairs or two bundles of hairs are derived in terms of Young's contact angle, elastic modulus and geometric sizes of the beams. Then, the hierarchical capillary adhesion of hairs is addressed. It is found that for multiple hairs or microcantilevers, the system tends to take a hierarchical structure as a result of the minimization of the total potential energy of the system. The level number of structural hierarchy increases with the increase in the number of hairs if they are sufficiently long. Additionally, we performed experiments to verify our theoretical solutions for the adhesion of microbeams

Cortical capillary dysfunction in patients suspected of Alzheimer’s disease

DEFF Research Database (Denmark)

Eskildsen, Simon Fristed; Gyldensted, Louise; Nagenthiraja, Kartheeban

Vascular risk factors are suspected to play a role in the etiology of Alzheimer’s disease. Recently, a model that relates capillary dysfunction to the development of AD was proposed[1]. The model predicts that capillary dysfunction in form of increased capillary transit time heterogeneity (CTH...

Multiple capillary biochemical analyzer

Science.gov (United States)

Dovichi, N.J.; Zhang, J.Z.

1995-08-08

A multiple capillary analyzer allows detection of light from multiple capillaries with a reduced number of interfaces through which light must pass in detecting light emitted from a sample being analyzed, using a modified sheath flow cuvette. A linear or rectangular array of capillaries is introduced into a rectangular flow chamber. Sheath fluid draws individual sample streams through the cuvette. The capillaries are closely and evenly spaced and held by a transparent retainer in a fixed position in relation to an optical detection system. Collimated sample excitation radiation is applied simultaneously across the ends of the capillaries in the retainer. Light emitted from the excited sample is detected by the optical detection system. The retainer is provided by a transparent chamber having inward slanting end walls. The capillaries are wedged into the chamber. One sideways dimension of the chamber is equal to the diameter of the capillaries and one end to end dimension varies from, at the top of the chamber, slightly greater than the sum of the diameters of the capillaries to, at the bottom of the chamber, slightly smaller than the sum of the diameters of the capillaries. The optical system utilizes optic fibers to deliver light to individual photodetectors, one for each capillary tube. A filter or wavelength division demultiplexer may be used for isolating fluorescence at particular bands. 21 figs.

Capillaries for use in a multiplexed capillary electrophoresis system

Science.gov (United States)

Yeung, E.S.; Chang, H.T.; Fung, E.N.

1997-12-09

The invention provides a side-entry optical excitation geometry for use in a multiplexed capillary electrophoresis system. A charge-injection device is optically coupled to capillaries in the array such that the interior of a capillary is imaged onto only one pixel. In Sanger-type 4-label DNA sequencing reactions, nucleotide identification (``base calling``) is improved by using two long-pass filters to split fluorescence emission into two emission channels. A binary poly(ethyleneoxide) matrix is used in the electrophoretic separations. 19 figs.

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

Science.gov (United States)

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.

Paramecium swimming in capillary tube

Science.gov (United States)

Jana, Saikat; Um, Soong Ho; Jung, Sunghwan

2012-04-01

Swimming organisms in their natural habitat need to navigate through a wide range of geometries and chemical environments. Interaction with boundaries in such situations is ubiquitous and can significantly modify the swimming characteristics of the organism when compared to ideal laboratory conditions. We study the different patterns of ciliary locomotion in glass capillaries of varying diameter and characterize the effect of the solid boundaries on the velocities of the organism. Experimental observations show that Paramecium executes helical trajectories that slowly transition to straight lines as the diameter of the capillary tubes decreases. We predict the swimming velocity in capillaries by modeling the system as a confined cylinder propagating longitudinal metachronal waves that create a finite pressure gradient. Comparing with experiments, we find that such pressure gradient considerations are necessary for modeling finite sized ciliary organisms in restrictive geometries.

Can positrons be guided by insulating capillaries?

International Nuclear Information System (INIS)

DuBois, R.D.; Toekesi, K.

2011-01-01

Complete text of publication follows. Investigations of guiding of few hundred eV antiparticles by macroscopic insulating capillaries have been described. Using subfemtoamp positron and electron beams, we demonstrated that a portion of the entering beams were transmitted and emerged in the direction of the capillary. We also demonstrated that the transmitted intensities decreased as the capillary tilt angle was increased (see Fig. 1). Both of these are indications of guiding. However, a comparison with transmitted photon data implies that the positron transmission may result from geometric factors associated with our diffuse beams and tapered capillary used in these studies. For electrons, the comparison indicates differences which could imply that even very low intensity beams can be guided. Measurements of the transmitted intensity as a function of charge entering the capillary were inconclusive as no major increases in the transmitted intensity were observed. 2D static simulations imply that our beam intensities, although extremely small with respect to previous guiding experiments, were capable of supplying sufficient charge for guiding to occur. Although not definitive, our study implies that sub-femtoamp beam intensities are sufficient to form charge patches and produce guiding. This may have been observed for electrons with the question remaining open for positrons. That guiding was not clearly seen may have been due to the capillary geometry used or it may indicate that although sufficient charge is being supplied, the surface and bulk resistivities of glass permit this charge to dissipate faster than it is formed. This aspect was not taken into consideration in our simulations but a crude estimate of the discharge rate implies that beam intensities on the order of pA, rather than fA as used here, may be required for guiding to occur in the capillaries used here. Additional studies are required to definitively answer the question as to whether antiparticles

Colloidal Asphaltene Deposition and Aggregation in Capillary Flow: Experiments and Mesoscopic Simulation

Science.gov (United States)

Boek, Edo S.; Ladva, Hemant K.; Crawshaw, John P.; Padding, Johan T.

2008-07-01

The aggregation and deposition of colloidal asphaltene in reservoir rock is a significant problem in the oil industry. To obtain a fundamental understanding of this phenomenon, we have studied the deposition and aggregation of colloidal asphaltene in capillary flow by experiment and simulation. For the simulation, we have used the stochastic rotation dynamics (SRD) method, in which the solvent hydrodynamic emerges from the collisions between the solvent particles, while the Brownian motion emerges naturally from the interactions between the colloidal asphaltene particles and the solvent. The asphaltene colloids interact through a screened Coulomb potential. We vary the well depth ɛ∝ and the flow rate v to obtain Peflow≫1 (hydrodynamic interactions dominate) and Re≪1 (Stokes flow). In the simulations, we impose a pressure drop over the capillary length and measure the corresponding solvent flow rate. We observe that the transient solvent flow rate decreases when the asphaltene particles become more "sticky". For a well depth ɛ∝ = 2kBT, a monolayer deposits on the capillary wall. With an increasing well depth, the capillary becomes totally blocked. The clogging is transient for ɛ∝ = 5kBT, but appears to be permanent for ɛ∝ = 10-20 kBT. We compare our simulation results with flow experiments in glass capillaries, where we use extracted asphaltenes in toluene, reprecipitated with n-heptane. In the experiments, the dynamics of asphaltene precipitation and deposition were monitored in a slot capillary using optical microscopy under flow conditions similar to those used in the simulation. Maintaining a constant flow rate of 5 μL min-1, we found that the pressure drop across the capillary first increased slowly, followed by a sharp increase, corresponding to a complete local blockage of the capillary. Doubling the flow rate to 10 μL min-1, we observe that the initial deposition occurs faster but the deposits are subsequently entrained by the flow. We

A computational study of the effect of capillary network anastomoses and tortuosity on oxygen transport.

Science.gov (United States)

Goldman, D; Popel, A S

2000-09-21

The objective of this study was to investigate the effects of capillary network anastomoses and tortuosity on oxygen transport in skeletal muscle, as well as the importance of muscle fibers in determining the arrangement of parallel capillaries. Countercurrent flow and random capillary blockage (e.g. by white blood cells) were also studied. A general computational model was constructed to simulate oxygen transport from a network of blood vessels within a rectangular volume of tissue. A geometric model of the capillary network structure, based on hexagonally packed muscle fibers, was constructed to produce networks of straight unbranched capillaries, capillaries with anastomoses, and capillaries with tortuosity, in order to examine the effects of these geometric properties. Quantities examined included the tissue oxygen tension and the capillary oxyhemoglobin saturation. The computational model included a two-phase simulation of blood flow. Appropriate parameters were chosen for working hamster cheek-pouch retractor muscle. Our calculations showed that the muscle-fiber geometry was important in reducing oxygen transport heterogeneity, as was countercurrent flow. Tortuosity was found to increase tissue oxygenation, especially when combined with anastomoses. In the absence of tortuosity, anastomoses had little effect on oxygen transport under normal conditions, but significantly improved transport when vessel blockages were present. Copyright 2000 Academic Press.

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

Science.gov (United States)

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%.

Capillary detectors

International Nuclear Information System (INIS)

Konijn, J.; Winter, K.; Vilain, P.; Wilquet, G.; Fabre, J.P.; Kozarenko, E.; Kreslo, I.; Goldberg, J.; Hoepfner, K.; Bay, A.; Currat, C.; Koppenburg, P.; Frekers, D.; Wolff, T.; Buontempo, S.; Ereditato, A.; Frenkel, A.; Liberti, B.; Martellotti, G.; Penso, G.; Ekimov, A.; Golovkin, S.; Govorun, V.; Medvedkov, A.; Vasil'chenko, V.

1998-01-01

The option for a microvertex detector using glass capillary arrays filled with liquid scintillator is presented. The status of capillary layers development and possible read-out techniques for high rate environment are reported. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

Nicotine-evoked cytosolic Ca2+ increase and cell depolarization in capillary endothelial cells of the bovine adrenal medulla

Directory of Open Access Journals (Sweden)

RAÚL VINET

2009-01-01

Full Text Available Endothelial cells are directly involved in many functions of the cardiovascular system by regulating blood flow and blood pressure through Ca2+ dependent exocitosis of vasoactive compounds. Using the Ca2+ indicator Fluo-3 and the patch-clamp technique, we show that bovine adrenal medulla capillary endothelial cells (B AMCECs respond to acetylcholine (ACh with a cytosolic Ca2+ increase and depolarization of the membrane potential (20.3±0.9 mV; n=23. The increase in cytosolic Ca2+ induced by 10µM ACh was mimicked by the same concentration of nicotine but not by muscarine and was blocked by 100 µM of hexamethonium. On the other hand, the increase in cytosolic Ca2+ could be depressed by nifedipine (0.01 -100 µM or withdrawal of extracellular Ca2+. Taken together, these results give evidence for functional nicotinic receptors (nAChRs in capillary endothelial cells of the adrenal medulla. It suggests that nAChRs in B AMCECs may be involved in the regulation of the adrenal gland's microcirculation by depolarizing the membrane potential, leading to the opening of voltage-activated Ca2+ channels, influx of external Ca2+ and liberation of vasoactive compounds.

Grand canonical Monte Carlo simulation study of capillary condensation between nanoparticles.

Science.gov (United States)

Kim, Seonmin; Ehrman, Sheryl H

2007-10-07

Capillary condensation at the nanoscale differs from condensation in the bulk phase, because it is a strong function of surface geometry and gas-surface interactions. Here, the effects of geometry on the thermodynamics of capillary condensation at the neck region between nanoparticles are investigated via a grand canonical Monte Carlo simulation using a two-dimensional lattice gas model. The microscopic details of the meniscus formation on various surface geometries are examined and compared with results of classical macromolecular theory, the Kelvin equation. We assume that the system is composed of a lattice gas and the surfaces of two particles are approximated by various shapes. The system is modeled on the basis of the molecular properties of the particle surface and lattice gas in our system corresponding to titania nanoparticles and tetraethoxy orthosilicate molecules, respectively. This system was chosen in order to reasonably emulate our previous experimental results for capillary condensation on nanoparticle surfaces. Qualitatively, our simulation results show that the specific geometry in the capillary zone, the surface-surface distance, and the saturation ratio are important for determining the onset and broadening of the liquid meniscus. The meniscus height increases continuously as the saturation ratio increases and the meniscus broadens faster above the saturation ratio of 0.90. The change of the radius of curvature of the particle surface affects the dimensions of the capillary zone, which drives more condensation in narrow zones and less condensation in wide zones. The increase of surface-surface distance results in the decrease of the meniscus height or even the disappearance of the meniscus entirely at lower saturation ratios. These effects are significant at the nanoscale and must be carefully considered in order to develop predictive relationships for meniscus height as a function of saturation conditions.

Detection of moving capillary front in porous rocks using X-ray and ultrasonic methods

Directory of Open Access Journals (Sweden)

Christian eDavid

2015-07-01

Full Text Available Several methods are compared for the detection of moving capillary fronts in spontaneous imbibition experiments where water invades dry porous rocks. These methods are: (i the continuous monitoring of the mass increase during imbibition, (ii the imaging of the water front motion using X-ray CT scanning, (iii the use of ultrasonic measurements allowing the detection of velocity, amplitude and spectral content of the propagating elastic waves, and (iv the combined use of X-ray CT scanning and ultrasonic monitoring. It is shown that the properties of capillary fronts depend on the heterogeneity of the rocks, and that the information derived from each method on the dynamics of capillary motion can be significantly different. One important result from the direct comparison of the moving capillary front position and the P wave attributes is that the wave amplitude is strongly impacted before the capillary front reaches the sensors, in contrast with the velocity change which is concomitant with the fluid front arrival in the sensors plane.

Measurement of Capillary Radius and Contact Angle within Porous Media.

Science.gov (United States)

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°.

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

Science.gov (United States)

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.

Acclimatization to 4100 m does not change capillary density or mRNA expression of potential angiogenesis regulatory factors in human skeletal muscle

DEFF Research Database (Denmark)

Lundby, Carsten; Pilegaard, Henriette; Andersen, Jesper L.

2004-01-01

growth factor (VEGF), a known target gene for hypoxia inducible factor 1 (HIF-1). We hypothesised that prolonged exposure to high altitude increases muscle capillary density and that this can be explained by an enhanced HIF-1alpha expression inducing an increase in VEGF expression. We measured mRNA...... or VEGF mRNA was not changed with prolonged hypoxic exposure in SLR, and both genes were similarly expressed in SLR and HAN. In SLR, whole body mass, mean muscle fibre area and capillary to muscle fibre ratio remained unchanged during acclimatization. The capillary to fibre ratio was lower in HAN than...... in SLR (2.4+/-0.1 vs 3.6+/-0.2; PRNA expression and capillary density are not significantly increased by 8 weeks of exposure to high altitude and are not increased in Aymara high-altitude natives compared with sea level residents....

Creeping motion of long bubbles and drops in capillary tubes

DEFF Research Database (Denmark)

Westborg, Henrik; Hassager, Ole

1989-01-01

The flow of inviscid bubbles and viscous drops in capillary tubes has been simulated by a Galerkin finite element method with surface tension included at the bubble/liquid interface. The results show good agreement with published experimental results. At low capillary numbers the front and the rear...... of the bubble are nearly spherical. As the capillary number increases the thickness of the wetting film between the tube wall and the bubble increases, and the bubble assumes a more slender shape with a characteristic bump at the rear. Recirculations are found in front and behind the bubble, which disappear...

Impacts on oil recovery from capillary pressure and capillary heterogeneities

Energy Technology Data Exchange (ETDEWEB)

Bognoe, Thomas

2008-07-01

The main conclusions drawn from this thesis are; 7 scientific papers are published on a broad variety of subjects, and describes in detail the experiments and research treated in this thesis. Scientific research has been performed, investigating the subjects of capillary pressure and capillary heterogeneities from different angles. This thesis discusses the findings in this study and aims to illustrate the benefits of the results obtained for further development of other experiments, and/or even the industrial benefits in field development. The methods for wettability alteration have developed throughout the work. From producing heterogeneous wettability alterations, the methods have improved to giving both radial and lateral uniform wettability alterations, which also remains unaltered throughout the duration of the experimental work. The alteration of wettability is dependent on initial water saturation, flow rate, aging time and crude oil composition. Capillary pressure and relative permeability curves have been measured for core plugs at different wettabilities using conventional centrifuge methods. The trends observed are mostly consistent with theory. The production mechanisms of strongly and moderately water wet chalk has been investigated. At strongly water wet conditions in fractured chalk; the flow is governed by capillary forces, showing strong impact from the fractures. At moderately water wet conditions, the impact of the fractures are absent, and a dispersed water front is observed during the displacement. The oil recovery is about the same, at the two wettabilities. Fracture crossing mechanisms at the same wettability conditions have been mapped. And the observations are consistent with those of the water floods. During strongly water wet displacement, the fracture crossing is occurring once the inlet core has reached endpoint of spontaneous imbibition. At moderately water wet conditions the fracture crossing is less abrupt, and creation of wetting

Wall modified photonic crystal fibre capillaries as porous layer open tubular columns for in-capillary micro-extraction and capillary chromatography

International Nuclear Information System (INIS)

Kazarian, Artaches A.; Sanz Rodriguez, Estrella; Deverell, Jeremy A.; McCord, James; Muddiman, David C.; Paull, Brett

2016-01-01

Wall modified photonic crystal fibre capillary columns for in-capillary micro-extraction and liquid chromatographic separations is presented. Columns contained 126 internal parallel 4 μm channels, each containing a wall bonded porous monolithic type polystyrene-divinylbenzene layer in open tubular column format (PLOT). Modification longitudinal homogeneity was monitored using scanning contactless conductivity detection and scanning electron microscopy. The multichannel open tubular capillary column showed channel diameter and polymer layer consistency of 4.2 ± 0.1 μm and 0.26 ± 0.02 μm respectively, and modification of 100% of the parallel channels with the monolithic polymer. The modified multi-channel capillaries were applied to the in-capillary micro-extraction of water samples. 500 μL of water samples containing single μg L"−"1 levels of polyaromatic hydrocarbons were extracted at a flow rate of 10 μL min"−"1, and eluted in 50 μL of acetonitrile for analysis using HPLC with fluorescence detection. HPLC LODs were 0.08, 0.02 and 0.05 μg L"−"1 for acenaphthene, anthracene and pyrene, respectively, with extraction recoveries of between 77 and 103%. The modified capillaries were also investigated briefly for direct application to liquid chromatographic separations, with the retention and elution of a standard protein (cytochrome c) under isocratic conditions demonstrated, proving chromatographic potential of the new column format, with run-to-run retention time reproducibility of below 1%. - Highlights: • Novel PS-DVB modified photonic crystal fibres for in-capillary micro-extraction. • New method for micro-extraction of PAHs and HPLC-FL detection at sub-ppb levels. • Demonstration of PS-DVB modified photonic crystal fibres for capillary bioseparations.

Wall modified photonic crystal fibre capillaries as porous layer open tubular columns for in-capillary micro-extraction and capillary chromatography

Energy Technology Data Exchange (ETDEWEB)

Kazarian, Artaches A. [Australian Centre for Research on Separation Science, School of Physical Sciences, University of Tasmania, Private Bag 75, Hobart, Tasmania 7001 (Australia); W.M. Keck FT-ICR-MS Laboratory, Department of Chemistry, North Carolina State University, Raleigh, NC (United States); Sanz Rodriguez, Estrella; Deverell, Jeremy A. [Australian Centre for Research on Separation Science, School of Physical Sciences, University of Tasmania, Private Bag 75, Hobart, Tasmania 7001 (Australia); McCord, James; Muddiman, David C. [W.M. Keck FT-ICR-MS Laboratory, Department of Chemistry, North Carolina State University, Raleigh, NC (United States); Paull, Brett, E-mail: Brett.Paull@utas.edu.au [Australian Centre for Research on Separation Science, School of Physical Sciences, University of Tasmania, Private Bag 75, Hobart, Tasmania 7001 (Australia); ARC Centre of Excellence for Electromaterials Science, School of Physical Sciences, University of Tasmania, Private Bag 75, Hobart, Tasmania 7001 (Australia)

2016-01-28

Wall modified photonic crystal fibre capillary columns for in-capillary micro-extraction and liquid chromatographic separations is presented. Columns contained 126 internal parallel 4 μm channels, each containing a wall bonded porous monolithic type polystyrene-divinylbenzene layer in open tubular column format (PLOT). Modification longitudinal homogeneity was monitored using scanning contactless conductivity detection and scanning electron microscopy. The multichannel open tubular capillary column showed channel diameter and polymer layer consistency of 4.2 ± 0.1 μm and 0.26 ± 0.02 μm respectively, and modification of 100% of the parallel channels with the monolithic polymer. The modified multi-channel capillaries were applied to the in-capillary micro-extraction of water samples. 500 μL of water samples containing single μg L{sup −1} levels of polyaromatic hydrocarbons were extracted at a flow rate of 10 μL min{sup −1}, and eluted in 50 μL of acetonitrile for analysis using HPLC with fluorescence detection. HPLC LODs were 0.08, 0.02 and 0.05 μg L{sup −1} for acenaphthene, anthracene and pyrene, respectively, with extraction recoveries of between 77 and 103%. The modified capillaries were also investigated briefly for direct application to liquid chromatographic separations, with the retention and elution of a standard protein (cytochrome c) under isocratic conditions demonstrated, proving chromatographic potential of the new column format, with run-to-run retention time reproducibility of below 1%. - Highlights: • Novel PS-DVB modified photonic crystal fibres for in-capillary micro-extraction. • New method for micro-extraction of PAHs and HPLC-FL detection at sub-ppb levels. • Demonstration of PS-DVB modified photonic crystal fibres for capillary bioseparations.

Increased presence of capillaries next to remodeling sites in adult human cancellous bone

DEFF Research Database (Denmark)

Kristensen, Helene Bjoerg; Andersen, Thomas Levin; Marcussen, Niels

2013-01-01

and at the level of the light-microscopically assessed contact of these three entities with the bone or canopy surfaces. Between 51 and 100 microm, their densities leveled to that found above quiescent surfaces. Electron microscopy asserted the close proximity between BRC canopies and capillaries lined...

Managment of superficial infantile capillary hemangiomas with topical timolol maleate solution.

Science.gov (United States)

Rizvi, Syed Ali Raza; Yusuf, Faraz; Sharma, Rajeev; Rizvi, Syed Wajahat Ali

2015-01-01

Capillary hemangioma is the most common benign tumor of eyelids and orbit in children. Recently, a topical beta blocker has been reported as an effective treatment for superficial capillary hemangiomas. We present a case report of two children having large capillary hemangiomas who responded well to topical treatment by 0.5% timolol maleate solution. After 12 months of treatment, the lesion has significantly reduced in size, thickness, and color in both cases. Thus, we conclude that long-term use of topical 0.5% timolol maleate solution is safe and effective in treating superficial capillary hemangiomas.

Effects of treadmill training on the arteriolar and venular portions of capillary in soleus muscle of young and middle-aged rats.

Science.gov (United States)

Suzuki, J; Gao, M; Batra, S; Koyama, T

1997-02-01

The effects of a 6-week programme of endurance training on soleus muscle capillarity were examined, in terms particularly of the proportions of arteriolar and venular capillaries and their capillary domain area, in young (3-week-old) and middle-aged (54-week-old) Wistar rats. Exercise protocols for the young training group were: 10-22.5 m min-1 60 min day-1 for 6 days a week, with a gradient of 7 degrees during the final 2 weeks; for the middle-aged training group, the protocols were: 10-20 m min-1. 50 min day-1 for 6 days a week. In both young and middle-aged training groups, the density of arteriolar capillaries was significantly increased (P demand. In both young and middle-aged rats, capillary domain area and Krogh's tissue cylinder radii in all capillary portions decreased after training. These results suggest that adaptive changes in oxygen transport system, identified as an increase in the arteriolar capillary and a reduction in diffusion distance for oxygen, were observed in middle-aged as well as in young rats. However, capillary angiogenesis induced by exercise appeared to be greater in young than in middle-aged rats.

Use of quasi-isoelectric buffers to limit protein adsorption in capillary zone electrophoresis.

Science.gov (United States)

Poitevin, Martine; Hammad, Karim; Ayed, Ichraf; Righetti, Pier Giorgio; Peltre, Gabriel; Descroix, Stephanie

2008-08-01

The use of quasi-isoelectric buffers consisting of narrow pH cuts of carrier ampholytes (NC) has been investigated to limit protein adsorption on capillary walls during capillary zone electrophoresis experiments. To quantify protein adsorption on the silica surface, a method derived from that of Towns and Regnier has been developed. alpha-Lactalbumin (14 kDa, pI 4.8) and alpha-chymotrypsinogen A (25 kDa, pI 9.2) have been used as model proteins. Acidic narrow pH cuts of carrier ampholytes (NC, pH 3.0) obtained from fractionation of Serva 4-9 carrier ampholytes were used as BGE in bare-silica capillaries, and allowed to decrease significantly protein adsorption, as compared to experiments performed with classical formate buffer. The use of NC as BGE appeared to be as efficient as the use of polydimethylacrylamide coating to prevent protein adsorption. This increase of protein recovery when using NC was attributed to the interaction of carrier ampholytes with the silica surface, leading to a shielding of the capillary wall.

Capillary density and capillary-to-fibre ratio in vastus lateralis muscle of untrained and trained men

Directory of Open Access Journals (Sweden)

W. M. Kilarski

2011-08-01

Full Text Available Muscle fibre profile area (Af, volume density (V_v, capillary-to-fibre ratio (CF and number of capillaries per fibre square millimetre (CD were determined from needle biopsies of vastus lateralis of twenty-four male volunteers (mean ± SD: age 25.4±5.8 years, height 178.6±5.5 cm, body mass 72.1±7.7 kg of different training background. Seven subjects were untrained students (group A, nine were national and sub-national level endurance athletes (group B with the background of 7.8±2.9 years of specialised training, and eight subjects were sprint-power athletes (group C with 12.8±8.7 years of specialised training. Muscle biopsies of vastus lateralis were analysed histochemically for mATPase. Capillaries were visualized and counted using CD31 antibodies against endothelial cells. There were significant differences in the V_v of type I and type II muscle fibres in both trained groups, B (51.8%; 25.6% and C (50.5%; 26.4%. However, in untrained group A that was treated as a reference group, the difference between V_v of type I and type II fibres was less prominent, nevertheless statistically significant (42.1%; 35.1%. There was also a significant difference in CF: 1.9 in group A and 2.1 in groups B and C. The number of capillaries per mm² (CD was 245 (group A, 308 (group B and 325 (group C. Significant differences (P<0.05 in CF and CD, were found only between group A (1.9; 245 and both groups of trained men, B and C (2.1; 308 and 325. However, endurance athletes (group B, such as long-distance runners, cyclists and cross country skiers, did not differ from the athletes representing short term, high power output sports (group C such as ice hockey, karate, ski-jumping, volleyball, soccer and modern dance.

Effect of surface roughness and softness on water capillary adhesion in apolar media.

Science.gov (United States)

Banerjee, Soumi; Mulder, Pieter; Kleijn, J Mieke; Cohen Stuart, Martien A

2012-06-28

The roughness and softness of interacting surfaces are both important parameters affecting the capillary condensation of water in apolar media, yet are poorly understood at present. We studied the water capillary adhesion between a cellulose surface and a silica colloidal probe in hexane by AFM force measurements. Nanomechanical measurements show that the Young's modulus of the cellulose layer in water is significantly less (~7 MPa) than in hexane (~7 GPa). In addition, the cellulose surface in both water and hexane is rather rough (6-10 nm) and the silica probe has a comparable roughness. The adhesion force between cellulose and silica in water-saturated hexane shows a time-dependent increase up to a waiting time of 200 s and is much (2 orders of magnitude) lower than that expected for a capillary bridge spanning the whole silica probe surface. This suggests the formation of one or more smaller bridges between asperities on both surfaces, which is confirmed by a theoretical analysis. The overall growth rate of the condensate cannot be explained from diffusion mediated capillary condensation alone; thin film flow due to the presence of a wetting layer of water at both the surfaces seems to be the dominant contribution. The logarithmic time dependence of the force can also be explained from the model of the formation of multiple capillary bridges with a distribution of activation times. Finally, the force-distance curves upon retraction show oscillations. Capillary condensation between an atomically smooth mica surface and the silica particle show less significant oscillations and the adhesion force is independent of waiting time. The oscillations in the force-distance curves between cellulose and silica may stem from multiple bridge formation between the asperities present on both surfaces. The softness of the cellulose surface can bring in additional complexities during retraction of the silica particle, also resulting in oscillations in the force-distance curves.

Capillaries modified by noncovalent anionic polymer adsorption for capillary zone electrophoresis, micellar electrokinetic capillary chromatography and capillary electrophoresis mass spectrometry

DEFF Research Database (Denmark)

Bendahl, L; Hansen, S H; Gammelgaard, Bente

2001-01-01

A simple coating procedure for generation of a high and pH-independent electroosmotic flow in capillary zone electrophoresis (CZE) and micellar electrokinetic capillary chromatography (MEKC) is described. The bilayer coating was formed by noncovalent adsorption of the ionic polymers Polybrene...... capillaries was (4.9+/-0.1) x 10(-4) cm2V(-1)s(-1) in a pH-range of 2-10 (ionic strength = 30 mM). When alkaline compounds were used as test substances intracapillary and intercapillary migration time variations (n = 6) were less than 1% relative standard deviation (RSD) and 2% RSD, respectively in the entire...... pH range. The coating was fairly stable in the presence of sodium dodecyl sulfate, and this made it possible to perform fast MEKC separations at low pH. When neutral compounds were used as test substances, the intracapillary migration time variations (n = 6) were less than 2% RSD in a pH range of 2...

Van de Graaff generator for capillary electrophoresis.

Science.gov (United States)

Lee, Seung Jae; Castro, Eric R; Guijt, Rosanne M; Tarn, Mark D; Manz, Andreas

2017-09-29

A new approach for high voltage capillary electrophoresis (CE) is proposed, which replaces the standard high voltage power supply with a Van de Graaff generator, a low current power source. Because the Van de Graaff generator is a current-limited source (10μA), potentials exceeding 100kV can be generated for CE when the electrical resistance of the capillary is maximized. This was achieved by decreasing the capillary diameter and reducing the buffer ionic strength. Using 2mM borate buffer and a 5μm i.d. capillary, fluorescently labeled amino acids were separated with efficiencies up to 3.5 million plates; a 5.7 fold improvement in separation efficiency compared to a normal power supply (NPS) typically used in CE. This separation efficiency was realized using a simple set-up without significant Joule heating, making the Van de Graaff generator a promising alternative for applying the high potentials required for enhancing resolution in the separation and analysis of highly complex samples, for example mixtures of glycans. Copyright © 2017 Elsevier B.V. All rights reserved.

Capillary dysfunction in Alzheimer’s disease correlates with cognitive decline

DEFF Research Database (Denmark)

Eskildsen, Simon Fristed; Gyldensted, Louise; Nagenthiraja, Kartheeban

Aim: We hypothesized that capillary dysfunction exists in Alzheimer’s disease (AD) and this can be determined by a relative increase in capillary transit time heterogeneity (CTH) in cortical gray matter compared to age-matched controls. Methods: We used dynamic susceptibility contrast (DSC...

Capillary interactions in nano-particle suspensions

International Nuclear Information System (INIS)

Bossev, D.P.; Warren, G.

2009-01-01

We have investigated the structures formed by colloidal particles suspended in solvents at volume fractions below 10% and interacting through capillary bridges. Such systems resemble colloidal gas of sticky nano-spheres that form pearl-necklace like chains that, in turn, induce strong viscoelasticity due to the formation of 3-D fractal network. The capillary force dominates the electrostatic and Van der Waals forces in solutions and can bridge multiple particles depending of the volume of the capillary bridge. We have investigated the morphology of the structures formed at different fractions of the bridging fluid. Small-angle neutron scattering (SANS) is used to study nanoparticles with an average diameter of 10 nm in polar and non-polar organic solvents at ambient temperatures. SANS intensity as a function of the scattering vector is analyzed as a product of a form factor, that depends on the particle shape, and a structure factor, that characterizes the interparticle inter reactions. The interaction of particles in polar solvents is considered to be through electrostatic repulsion and the data is successfully fitted by Hayter-Penfold mean spherical approximation (HPMSA). Computer simulations of a pearl necklace-like chain of spheres is conducted to explain the structure factor when capillary bridges are present. Alternatively, we have analyzed the slope of the intensity at low scattering vector in a double logarithmic plot to determine the dimension of the fractal structures formed by the particles at different volume fraction of the bridging fluid. We have also studied the properties of the capillary bridge between a pair of particles. The significance of this study is to explore the possibility of using capillary force as a tool to engineer new colloidal structures and materials in solutions and to optimize their viscoelastic properties. (author)

Integrated refractive index optical ring resonator detector for capillary electrophoresis.

Science.gov (United States)

Zhu, Hongying; White, Ian M; Suter, Jonathan D; Zourob, Mohammed; Fan, Xudong

2007-02-01

We developed a novel miniaturized and multiplexed, on-capillary, refractive index (RI) detector using liquid core optical ring resonators (LCORRs) for future development of capillary electrophoresis (CE) devices. The LCORR employs a glass capillary with a diameter of approximately 100 mum and a wall thickness of a few micrometers. The circular cross section of the capillary forms a ring resonator along which the light circulates in the form of the whispering gallery modes (WGMs). The WGM has an evanescent field extending into the capillary core and responds to the RI change due to the analyte conducted in the capillary, thus permitting label-free measurement. The resonating nature of the WGM enables repetitive light-analyte interaction, significantly enhancing the LCORR sensitivity. This LCORR architecture achieves dual use of the capillary as a sensor head and a CE fluidic channel, allowing for integrated, multiplexed, and noninvasive on-capillary detection at any location along the capillary. In this work, we used electro-osmotic flow and glycerol as a model system to demonstrate the fluid transport capability of the LCORRs. In addition, we performed flow speed measurement on the LCORR to demonstrate its flow analysis capability. Finally, using the LCORR's label-free sensing mechanism, we accurately deduced the analyte concentration in real time at a given point on the capillary. A sensitivity of 20 nm/RIU (refractive index units) was observed, leading to an RI detection limit of 10-6 RIU. The LCORR marries photonic technology with microfluidics and enables rapid on-capillary sample analysis and flow profile monitoring. The investigation in this regard will open a door to novel high-throughput CE devices and lab-on-a-chip sensors in the future.

Nanoparticle-based capillary electroseparation of proteins in polymer capillaries under physiological conditions

DEFF Research Database (Denmark)

Nilsson, C.; Harwigsson, I.; Becker, K.

2010-01-01

Totally porous lipid-based liquid crystalline nanoparticles were used as pseudostationary phase for capillary electroseparation with LIF detection of proteins at physiological conditions using unmodified cyclic olefin copolymer capillaries (Topas (R), 6.7 cm effective length). In the absence of n...... at protein friendly conditions. The developed capillary-based method facilitates future electrochromatography of proteins on polymer-based microchips under physiological conditions and enables the initial optimization of separation conditions in parallel to the chip development....

Western Blotting using Capillary Electrophoresis

OpenAIRE

Anderson, Gwendolyn J.; Cipolla, Cynthia; Kennedy, Robert T.

2011-01-01

A microscale Western blotting system based on separating sodium-dodecyl sulfate protein complexes by capillary gel electrophoresis followed by deposition onto a blotting membrane for immunoassay is described. In the system, the separation capillary is grounded through a sheath capillary to a mobile X-Y translation stage which moves a blotting membrane past the capillary outlet for protein deposition. The blotting membrane is moistened with a methanol and buffer mixture to facilitate protein a...

A macrothermodynamic approach to the limit of reversible capillary condensation.

Science.gov (United States)

Trens, Philippe; Tanchoux, Nathalie; Galarneau, Anne; Brunel, Daniel; Fubini, Bice; Garrone, Edoardo; Fajula, François; Di Renzo, Francesco

2005-08-30

The threshold of reversible capillary condensation is a well-defined thermodynamic property, as evidenced by corresponding states treatment of literature and experimental data on the lowest closure point of the hysteresis loop in capillary condensation-evaporation cycles for several adsorbates. The nonhysteretical filling of small mesopores presents the properties of a first-order phase transition, confirming that the limit of condensation reversibility does not coincide with the pore critical point. The enthalpy of reversible capillary condensation can be calculated by a Clausius-Clapeyron approach and is consistently larger than the condensation heat in unconfined conditions. Calorimetric data on the capillary condensation of tert-butyl alcohol in MCM-41 silica confirm a 20% increase of condensation heat in small mesopores. This enthalpic advantage makes easier the overcoming of the adhesion forces by the capillary forces and justifies the disappearing of the hysteresis loop.

Fluctuations of wormlike micelle fluids in capillary flow

Science.gov (United States)

Salipante, Paul; Meek, Stephen; Hudson, Steven; Polymers; Complex Fluids Group Team

2017-11-01

We investigate the effect of entrance geometry on the flow stability of wormlike micelles solutions in capillary flow. These solutions exhibit strong shear thinning behavior resulting from micelle breakage and have been observed to undergo large flow rate fluctuations. We investigate these fluctuations using simultaneous measurements of flow rate and pressure drop across a capillary, and we adjust entrance geometry. With a tapered constriction, we observe large persistent fluctuations above a critical flow rate, characterized by rapid decreases in the pressure drop with corresponding increase in flow rate followed by a period of recovery where pressure increases and flow rate decreases. Flow field observations in the tapered entrance show large flow circulations. An abrupt contraction produces smaller transient fluidized jets forming upstream of the constriction and the magnitude of the fluctuations are significantly diminished. The effect of fluid properties is studied by comparing the magnitude and timescales of the fluctuations for surfactant systems with different relaxation times. The onset of fluctuations is compared to a criterion for the onset of elastic instabilities and the magnitude is compared to estimates for changes in channel resistance. NIST on a Chip.

The Effect of Ion Motion on Laser-Driven Plasma Wake in Capillary

International Nuclear Information System (INIS)

Zhou Suyun; Li Yanfang; Chen Hui

2016-01-01

The effect of ion motion in capillary-guided laser-driven plasma wake is investigated through rebuilding a two-dimensional analytical model. It is shown that laser pulse with the same power can excite more intense wakefield in the capillary of a smaller radius. When laser intensity exceeds a critical value, the effect of ion motion reducing the wakefield rises, which becomes significant with a decrease of capillary radius. This phenomenon can be attributed to plasma ions in smaller capillary obtaining more energy from the plasma wake. The dependence of the difference value between maximal scalar potential of wake for two cases of ion rest and ion motion on the radius of the capillary is discussed. (paper)

Exploring Ultimate Water Capillary Evaporation in Nanoscale Conduits.

Science.gov (United States)

Li, Yinxiao; Alibakhshi, Mohammad Amin; Zhao, Yihong; Duan, Chuanhua

2017-08-09

Capillary evaporation in nanoscale conduits is an efficient heat/mass transfer strategy that has been widely utilized by both nature and mankind. Despite its broad impact, the ultimate transport limits of capillary evaporation in nanoscale conduits, governed by the evaporation/condensation kinetics at the liquid-vapor interface, have remained poorly understood. Here we report experimental study of the kinetic limits of water capillary evaporation in two dimensional nanochannels using a novel hybrid channel design. Our results show that the kinetic-limited evaporation fluxes break down the limits predicated by the classical Hertz-Knudsen equation by an order of magnitude, reaching values up to 37.5 mm/s with corresponding heat fluxes up to 8500 W/cm 2 . The measured evaporation flux increases with decreasing channel height and relative humidity but decreases as the channel temperature decreases. Our findings have implications for further understanding evaporation at the nanoscale and developing capillary evaporation-based technologies for both energy- and bio-related applications.

Surgical Treatment of Dermatomal Capillary Malformations in the Adult Face

Directory of Open Access Journals (Sweden)

Yoojeong Kim

2012-03-01

Full Text Available BackgroundFacial capillary malformations (CMs rarely recede; they often become darker and raised in proportion to their growth. These malformations may hypertrophy in adulthood, resulting in increased disfigurement and dysfunction. Laser treatment is considered a first-line therapy for focal CMs, but thick wide lesions, which are accompanied by hypertrophy and have a well-circumscribed nodularity, may be treated with surgical excision and reconstruction.MethodsWe retrospectively reviewed the records of 25 consecutive patients who had undergone complete or partial excisions of facial capillary malformations in our unit. After the excisions, the defects that encompassed their facial aesthetic units were subsequently covered by various methods, including primary closures, local flaps, expanded flaps, split-thickness skin grafts, and full thickness skin grafts.ResultsThe data demonstrated satisfactory results and reliability. Our patients were treated without significant complications, and all of the patients were moderately or fully satisfied with the outcome of their surgeries.ConclusionsAmong the many reconstructive options for adult patients with facial capillary malformations, thick split-thickness skin grafts can be a good choice for the coverage of widely excised wounds.

Capillary gas-solid chromatography

International Nuclear Information System (INIS)

Berezkin, V.G.

1996-01-01

Modern state of gas adsorption chromatography in open capillary columns has been analyzed. The history of the method development and its role in gas chromatography, ways to construct open adsorptional capillary columns, foundations of the theory of retention and washing of chromatographic regions in gas adsorption capillary columns have been considered. The fields is extensively and for analyzing volatile compounds of different isotopic composition, inorganic and organic gases, volatile organic polar compounds, aqueous solutions of organic compounds. Separation of nuclear-spin isomers and isotopes of hydrogen is the first illustrative example of practical application of the adsorption capillary chromatography. It is shown that duration of protium and deuterium nuclear isomers may be reduced if the column temperature is brought to 47 K

Growth of metal-organic framework HKUST-1 in capillary using liquid-phase epitaxy for open-tubular capillary electrochromatography and capillary liquid chromatography.

Science.gov (United States)

Bao, Tao; Zhang, Juan; Zhang, Wenpeng; Chen, Zilin

2015-02-13

Much attention is being paid to applying metal-organic frameworks (MOFs) as stationary phases in chromatography because of their fascinating properties, such as large surface-to-volume ratios, high levels of porosity, and selective adsorption. HKUST-1 is one of the best-studied face-centered-cubic MOF containing nano-sized channels and side pockets for film growth. However, growth of HKUST-1 framework inside capillary column as stationary phase for capillary electrochromatography is a challenge work. In this work, we carry out the growth of HKUST-1 on the inner wall of capillary by using liquid-phase epitaxy process at room temperature. The fabricated HKUST-1@capillary can be successfully used for the separation of substituted benzene including methylbenzene, ethylbenzene, styrene, chlorobenzene, bromobenzene, o-dichlorobenzene, benzene series, phenolic acids, and benzoic acids derivates. High column efficiency of 1.5×10(5) N/m for methylbenzene was achieved. The formation of HKUST-1 grown in the capillary was confirmed and characterized by scanning electron microscopy images, Fourier transform infrared spectra and X-ray diffraction. The column showed long lifetime and excellent stability. The relative standard deviations for intra-day and inter-day repeatability of the HKUST-1@capillary were lower than 7%. Copyright © 2015 Elsevier B.V. All rights reserved.

Capillary condensation of adsorbates in porous materials.

Science.gov (United States)

Horikawa, Toshihide; Do, D D; Nicholson, D

2011-11-14

Hysteresis in capillary condensation is important for the fundamental study and application of porous materials, and yet experiments on porous materials are sometimes difficult to interpret because of the many interactions and complex solid structures involved in the condensation and evaporation processes. Here we make an overview of the significant progress in understanding capillary condensation and hysteresis phenomena in mesopores that have followed from experiment and simulation applied to highly ordered mesoporous materials such as MCM-41 and SBA-15 over the last few decades. Copyright © 2011 Elsevier B.V. All rights reserved.

Visualization of Radial Peripapillary Capillaries Using Optical Coherence Tomography Angiography: The Effect of Image Averaging.

Directory of Open Access Journals (Sweden)

Shelley Mo

Full Text Available To assess the effect of image registration and averaging on the visualization and quantification of the radial peripapillary capillary (RPC network on optical coherence tomography angiography (OCTA.Twenty-two healthy controls were imaged with a commercial OCTA system (AngioVue, Optovue, Inc.. Ten 10x10° scans of the optic disc were obtained, and the most superficial layer (50-μm slab extending from the inner limiting membrane was extracted for analysis. Rigid registration was achieved using ImageJ, and averaging of each 2 to 10 frames was performed in five ~2x2° regions of interest (ROI located 1° from the optic disc margin. The ROI were automatically skeletonized. Signal-to-noise ratio (SNR, number of endpoints and mean capillary length from the skeleton, capillary density, and mean intercapillary distance (ICD were measured for the reference and each averaged ROI. Repeated measures analysis of variance was used to assess statistical significance. Three patients with primary open angle glaucoma were also imaged to compare RPC density to controls.Qualitatively, vessels appeared smoother and closer to histologic descriptions with increasing number of averaged frames. Quantitatively, number of endpoints decreased by 51%, and SNR, mean capillary length, capillary density, and ICD increased by 44%, 91%, 11%, and 4.5% from single frame to 10-frame averaged, respectively. The 10-frame averaged images from the glaucomatous eyes revealed decreased density correlating to visual field defects and retinal nerve fiber layer thinning.OCTA image registration and averaging is a viable and accessible method to enhance the visualization of RPCs, with significant improvements in image quality and RPC quantitative parameters. With this technique, we will be able to non-invasively and reliably study RPC involvement in diseases such as glaucoma.

Strength, shrinkage, erodibility and capillary flow characteristics of cement-treated recycled pavement materials

Directory of Open Access Journals (Sweden)

William Fedrigo

2017-09-01

Full Text Available Full-depth recycling with portland cement (FDR-PC has been widely used for pavement rehabilitation; however, doubts remain regarding factors affecting some properties of the recycled material. Aiming on quantifying the effects of those factors on the strength, drying shrinkage, erodibility, capillary rise and absorption of cement-treated mixtures (CTM of reclaimed asphalt pavement (RAP and graded crushed stone, tests were conducted considering different RAP contents, cement contents, compaction efforts and curing times. Cement addition increased the mixtures strength and reduced their erodibility and capillary flow characteristics, but increased shrinkage. Low cement contents resulted in acceptable strength for CTM, but in high capillary rise and absorption, not being suitable if the layer is exposed to long periods of water soaking. Higher compaction effort led to similar effects as cement addition, counterbalancing low cement contents usage and reducing costs and shrinkage cracking risk. Strength and shrinkage showed higher growth rates at early stages, and then precautions should be taken in order to avoid moisture loss. Increasing RAP content decreased strength; though, RAP effect on the other properties was statistically non-significant, indicating a similar behaviour as CTM without RAP. Considering the studied properties, the mixture with most satisfactory behaviour for field applications was identified. The results highlighted strength is not the only property to be considered when designing FDR-PC mixtures; although presenting acceptable strength, some mixtures may fail due to shrinkage cracking or erosion, when exposed to water content variations. Keywords: Full-depth recycling with cement, Strength, Drying shrinkage, Erodibility, Capillary rise, Absorption

Ring cavity for a Raman capillary waveguide amplifier

Science.gov (United States)

Kurnit, N.A.

1981-01-27

A regenerative ring amplifier and regenerative ring oscillator are described which function to feed back a portion of the Stokes signal to complete the ring cavity. The ring cavity configuration allows the CO/sub 2/ laser pump signal and Stokes signal to copropagate through the Raman capillary waveguide amplifier. A Raman capillary waveguide amplifier is also provided in the return leg of the ring cavity to increase gain without increasing the round trip time. Additionally, the ring cavity can be designed such that the amplified Stokes signal is synchronous with the mode-locked spikes of the incoming CO/sub 2/ laser pump signal.

Ring cavity for a Raman capillary waveguide amplifir

Science.gov (United States)

Kurnit, N.A.

1981-01-27

A regenerative ring amplifier and regenerative ring oscillator are described which function to feed back a portion of the Stokes signal to complete the ring cavity. The ring cavity configuration allows the CO/sub 2/ laser pump signal and Stokes signal to copropagate through the Raman capillary waveguide amplifier. A Raman capillary waveguide amplifier is also provided in the return leg of the ring cavity to increase gain without increasing the round trip time. Additionally, the ring cavity can be designed such that the amplified Stokes signal is synchronous with the mode-locked spikes of the incoming CO/sub 2/ laser pump signal.

Laws of physics help explain capillary non-perfusion in diabetic retinopathy.

Science.gov (United States)

Stefánsson, E; Chan, Y K; Bek, T; Hardarson, S H; Wong, D; Wilson, D I

2018-02-01

The purpose is to use laws of physics to elucidate the mechanisms behind capillary non-perfusion in diabetic retinopathy. In diabetic retinopathy, loss of pericytes weakens capillary walls and the vessel dilates. A dilated capillary has reduced resistance to flow, therefore increased flow in that vessel and decreased in adjoining capillaries. A preferential shunt vessel is thus formed from the dilated capillary and the adjacent capillaries become non-perfused. We apply the laws of Laplace and Hagen-Poiseuille to better understand the phenomena that lead to capillary non-perfusion. These laws of physics can give a foundation for physical or mathematical models to further elucidate this field of study. The law of Laplace predicts that a weaker vessel wall will dilate, assuming constant transmural pressure. The Hagen-Poiseuille equation for flow and the Ostwald-de Waele relationship for viscosity predict that a dilated vessel will receive a higher portion of the fluid flow than the adjoining capillaries. Viscosity will decrease in the dilated vessel, furthering the imbalance and resulting in a patch of non-perfused capillaries next to the dilated 'preferential' shunt vessel. Physical principles support or inspire novel hypotheses to explain poorly understood phenomena in ophthalmology. This thesis of pericyte death and capillary remodelling, which was first proposed by Cogan and Kuwabara, already agrees with histological and angiographical observations in diabetic retinopathy. We have shown that it is also supported by classical laws of physics.

Instrumental development of novel detection and separation methods for capillary electrophoresis

Energy Technology Data Exchange (ETDEWEB)

Garner, Tommy [Iowa State Univ., Ames, IA (United States)

1993-07-01

After a general introduction, this thesis is divided into 3 parts: indirect fluorescence detection of sugars separated by capillary zone electrophoresis with visible laser excitation, absorption detection in capillary electrophoresis by fluorescence energy transfer, and increased selectivity for electrochromatography by dynamic ion exchange.

Cortical capillary dysfunction in patients suspected of Alzheimer’s disease

DEFF Research Database (Denmark)

Eskildsen, Simon Fristed; Gyldensted, Louise; Nagenthiraja, Kartheeban

) leads to inefficient oxygen extraction and eventually to tissue hypoxia. In this study we investigated regional cerebral blood flow (CBF) and CTH in cortical gray matter of AD patients and controls using dynamic susceptibility contrast (DSC) magnetic resonance imaging (MRI) and surface based statistics.......Vascular risk factors are suspected to play a role in the etiology of Alzheimer’s disease. Recently, a model that relates capillary dysfunction to the development of AD was proposed[1]. The model predicts that capillary dysfunction in form of increased capillary transit time heterogeneity (CTH...

Mixed Capillary Venous Retroperitoneal Hemangioma

Directory of Open Access Journals (Sweden)

Mohit Godar

2013-01-01

Full Text Available We report a case of mixed capillary venous hemangioma of the retroperitoneum in a 61-year-old man. Abdominal ultrasonography showed a mass to be hypoechoic with increased flow in color Doppler imaging. Dynamic contrast-enhanced computed tomography revealed a centripetal filling-in of the mass, located anterior to the left psoas muscle at the level of sacroiliac joint. On the basis of imaging features, preoperative diagnosis of hemangioma was considered and the mass was excised by laparoscopic method. Immunohistochemical studies were strongly positive for CD31 and CD34, and negative for calretinin, EMA, WT1, HMB45, Ki67, synaptophysin, and lymphatic endothelial cell marker D2–40. Histologically, the neoplasm was diagnosed as mixed capillary venous hemangioma.

Role of substrate aspect ratio on the robustness of capillary alignment

International Nuclear Information System (INIS)

Broesch, David J.; Shiang, Edward; Frechette, Joelle

2014-01-01

Capillary forces associated with liquid bridges formed across solid substrates are routinely exploited to align and assemble micro- and nanoscale devices. The magnitude of these forces plays a critical role in minimizing substrate misalignment and therefore should be controlled for robust and reliable fabrication process. We explore through simulations and experiments the role of the substrate aspect ratio (L/W) on capillary restoring forces and torques. Simulations show that increasing the aspect ratio of the substrates increases the capillary torques and forces when the substrates are misaligned through either lateral or rotational perturbations. The effect of substrate area, perimeter, and liquid volume are also systematically explored to show that the increase in restoring torque is caused by an increase in aspect ratio. A simple theoretical model based on the geometry of the system shows excellent agreement with Surface Evolver simulations. Finally, parameters from experimental flip-chip devices [Josell, D. Wallace, W.E. Warren, J.A. Wheeler, D. Powell, A.C. J. Electron. Packag. 124, 227, (2002)] are used in our simulations to show how current capillary self-alignment schemes could benefit from using rectangular substrate shapes with aspect ratio greater than one

Numerical simulations of capillary barrier field tests

International Nuclear Information System (INIS)

Morris, C.E.; Stormont, J.C.

1997-01-01

Numerical simulations of two capillary barrier systems tested in the field were conducted to determine if an unsaturated flow model could accurately represent the observed results. The field data was collected from two 7-m long, 1.2-m thick capillary barriers built on a 10% grade that were being tested to investigate their ability to laterally divert water downslope. One system had a homogeneous fine layer, while the fine soil of the second barrier was layered to increase its ability to laterally divert infiltrating moisture. The barriers were subjected first to constant infiltration while minimizing evaporative losses and then were exposed to ambient conditions. The continuous infiltration period of the field tests for the two barrier systems was modelled to determine the ability of an existing code to accurately represent capillary barrier behavior embodied in these two designs. Differences between the field test and the model data were found, but in general the simulations appeared to adequately reproduce the response of the test systems. Accounting for moisture retention hysteresis in the layered system will potentially lead to more accurate modelling results and is likely to be important when developing reasonable predictions of capillary barrier behavior

Self-Assembly of Microscale Parts through Magnetic and Capillary Interactions

Directory of Open Access Journals (Sweden)

Madan Dubey

2011-03-01

Full Text Available Self-assembly is a promising technique to overcome fundamental limitations with integrating, packaging, and general handling of individual electronic-related components with characteristic lengths significantly smaller than 1 mm. Here we describe the use of magnetic and capillary forces to self-assemble 280 µm sized silicon building blocks into interconnected structures which approach a three-dimensional crystalline configuration. Integrated permanent magnet microstructures provided magnetic forces, while a low-melting-point solder alloy provided capillary forces. A finite element model of forces between the magnetic features demonstrated the utility of magnetic forces at this size scale. Despite a slight departure from designed dimensions in the actual fabricated parts, the combination of magnetic and capillary forces improved the assembly yield to 8%, over approximately 0.1% achieved previously with capillary forces alone.

Capillary concentrators for synchrotron radiation beamlines

International Nuclear Information System (INIS)

Heald, S.M.; Brewe, D.L.; Kim, K.H.; Brown, F.C.; Barg, B.; Stern, E.A.

1996-01-01

Capillary concentrators condense x-rays by multiple reflections down a gradually tapering capillary. They can provide sub-micron beam spots, and are promising candidates for use in the next generation x-ray microprobe beamlines. The weak energy dependence of their properties make them especially useful for energy scanning applications such as micro-XAFS. This paper examines the potential performance of capillary optics for an x-ray microprobe, as well as some practical issues such as fabrication and alignment. Best performance at third generation sources requires long capillaries, and the authors have been using fiber optics techniques to fabricate capillaries up to one meter in length. The performance of shorter (less than about 0.5 m) capillaries has often been found to agree well with theoretical calculations, indicating the inner surface is a high quality x-ray reflector. These capillaries have been tested at the NSLS for imaging and micro-XAFS down to 2.6 microm resolution with excellent results. On an unfocused bend magnet line flux density approaching 10 6 ph/sec/microm 2 has been achieved. While nearly optimum profiles have been achieved for longer capillaries, the results have been disappointing, and alignment problems are suspected. The dramatic improvement in performance possible at third generation synchrotrons such as the APS is discussed along with improvements possible by using the capillaries in conjunction with coupling optics

Heterogeneity of capillary spacing in the hypertrophied plantaris muscle from young-adult and old rats.

NARCIS (Netherlands)

Degens, H.; Morse, C.I.; Hopman, M.T.E.

2009-01-01

Heterogeneity of capillary spacing may affect tissue oxygenation. The determinants of heterogeneity of capillary spacing are, however, unknown. To investigate whether 1) impaired angiogenesis and increased heterogeneity of capillary spacing delays development of hypertrophy during aging and 2)

Early Regimes of Water Capillary Flow in Slit Silica Nanochannels

DEFF Research Database (Denmark)

Oyarzua, Elton; Walther, Jens Honore; Mejia, Andres

2015-01-01

on the dynamics of capillaryfilling. The results indicate that the nanoscale imbibition process is divided into three main flow regimes:an initial regime where the capillary force is balanced only by the inertial drag and characterized by aconstant velocity and a plug flow profile. In this regime, the meniscus...... velocity profiles identify the passage froman inviscid flow to a developing Poiseuille flow. Gas density profiles ahead of the capillary front indicatea transient accumulation of air on the advancing meniscus. Furthermore, slower capillary filling ratescomputed for higher air pressures reveal a significant...... retarding effect of the gas displaced by the advancing meniscus....

Capillary pumped loop body heat exchanger

Science.gov (United States)

Swanson, Theodore D. (Inventor); Wren, deceased, Paul (Inventor)

1998-01-01

A capillary pumped loop for transferring heat from one body part to another body part, the capillary pumped loop comprising a capillary evaporator for vaporizing a liquid refrigerant by absorbing heat from a warm body part, a condenser for turning a vaporized refrigerant into a liquid by transferring heat from the vaporized liquid to a cool body part, a first tube section connecting an output port of the capillary evaporator to an input of the condenser, and a second tube section connecting an output of the condenser to an input port of the capillary evaporator. A wick may be provided within the condenser. A pump may be provided between the second tube section and the input port of the capillary evaporator. Additionally, an esternal heat source or heat sink may be utilized.

Do Anesthetic Techniques Influence the Threshold for Glomerular Capillary Hemorrhage Induced in Rats by Contrast-Enhanced Diagnostic Ultrasound?

Science.gov (United States)

Miller, Douglas L; Lu, Xiaofang; Fabiilli, Mario; Dou, Chunyan

2016-02-01

Glomerular capillary hemorrhage can be induced by ultrasonic cavitation during contrast-enhanced diagnostic ultrasound (US) exposure, an important nonthermal US bioeffect. Recent studies of pulmonary US exposure have shown that thresholds for another nonthermal bioeffect of US, pulmonary capillary hemorrhage, is strongly influenced by whether xylazine is included in the specific anesthetic technique. The objective of this study was to determine the influence of xylazine on contrast-enhanced diagnostic US-induced glomerular capillary hemorrhage. In this study, anesthesia with ketamine only was compared to ketamine plus xylazine for induction of glomerular capillary hemorrhage in rats by 1.6-MHz intermittent diagnostic US with a microsphere contrast agent (similar to Definity; Lantheus Medical Imaging, Inc, North Billerica, MA). Glomerular capillary hemorrhage was measured as a percentage of glomeruli with hemorrhage found in histologic sections for groups of rats scanned at different peak rarefactional pressure amplitudes. There was a significant difference between the magnitude of the glomerular capillary hemorrhage between the anesthetics at 2.3 MPa, with 45.6% hemorrhage for ketamine only, increasing to 63.2% hemorrhage for ketamine plus xylazine (P Ultrasound in Medicine.

Investigation into the suitability of capillary tubes for microcrystalline testing.

Science.gov (United States)

Elie, Leonie E; Baron, Mark G; Croxton, Ruth S; Elie, Mathieu P

2013-07-01

A comparison between microcrystalline tests performed on microscope slides and flat capillary tubes with inner diameters ranging from 0.1 to 0.7 mm was carried out to explore the appropriateness of tubes for rapid testing of suspected drugs of abuse in the laboratory as well as in the field. Tests for mephedrone, cocaine, and phencyclidine were chosen as examples to investigate the handling of the capillary tubes, the influence on crystal habit, size, and the effects on the limit of detection. Image stacking software was used to increase the depth of field of micrographs taken from developed microcrystals greatly enhancing the interpretability even months after carrying out the microcrystalline test. Additionally, the potential of seeding capillary tubes with a reagent was studied. Pre-treatment of tubes would allow microcrystalline tests to be carried out quicker and anywhere without the necessity of taking along expensive and hazardous reagents. The sealing of capillary tubes containing developed microcrystalline tests in order to preserve results for a long period of time was successfully done by applying paraffin wax to the open ends. Finally, it was concluded that capillary tubes are suitable vessels for performing microcrystalline tests. The increased portability of the improved set-up allows tests to be safely executed outside laboratories without impairing the quality of the result. Findings were applied to six legal high samples purchased online between May and August 2011. The active ingredients like MDAI as well as cutting agents like caffeine were successfully identified using the microcrystalline test technique in capillary tubes. Copyright © 2012 John Wiley & Sons, Ltd.

Capillary waves of compressible fluids

International Nuclear Information System (INIS)

Falk, Kerstin; Mecke, Klaus

2011-01-01

The interplay of thermal noise and molecular forces is responsible for surprising features of liquids on sub-micrometer lengths-in particular at interfaces. Not only does the surface tension depend on the size of an applied distortion and nanoscopic thin liquid films dewet faster than would be expected from hydrodynamics, but also the dispersion relation of capillary waves differ at the nanoscale from the familiar macroscopic behavior. Starting with the stochastic Navier-Stokes equation we study the coupling of capillary waves to acoustic surface waves which is possible in compressible fluids. We find propagating 'acoustic-capillary waves' at nanometer wavelengths where in incompressible fluids capillary waves are overdamped.

Theoretical investigation of adiabatic capillary tubes working with propane/n-butane/iso-butane blends

International Nuclear Information System (INIS)

Fatouh, M.

2007-01-01

In this paper, a theoretical model is developed to predict the refrigerant flow characteristics in adiabatic capillary tubes using propane/n-butane/iso-butane mixtures as working fluids in a domestic refrigerator. This model is based on the mass, energy and momentum conservation equations for a homogeneous refrigerant flow under different inlet conditions, such as subcooled, saturated and two phase flow. The effects of the inlet pressure (8-16 bar), inlet vapor quality (0.001-15%), inlet subcooling degree (1-15 o C), mass flow rate (1-5 kg/h), propane mass fraction (0.5-0.7), capillary tube inner diameter (0.6-1.0 mm) and the tube surface roughness on the capillary tube length are predicted. The results showed that the present model predicts data that are very close to the available experimental data in the literature with an average error of 2.65%. The pressure of the hydrocarbon mixture (HCM) decreases, while its vapor quality, specific volume and Mach number increase along the capillary tube. Also, the results indicated that the capillary tube length is largely dependent on the capillary tube diameter. Other parameters such as mass flow rate, inlet pressure, subcooling degree (or quality) and relative roughness influence the capillary tube length in that order. The capillary tube length as a function of the significant parameters is presented in equation form. Also, capillary tube selection charts either to predict the mass flow rates of propane/n-butane/iso-butane mixtures through adiabatic capillary tubes or to select the capillary tube size according to the required applications are developed. The comparison between R12, R134a and the hydrocarbon mixture (HCM) of propane/n-butane/iso-butane indicated that for a given mass flow rate, the pressure drop per unit length is about 4.13, 5.0 and 12.0 bar/m for R12, R134a and HCM, respectively. The ratios of the average mass flow rate of the HCM with a propane mass fraction of 0.6 to those of R12 and R134a are about

Monoliths in capillary electrochromatography and capillary liquid chromatography in conjunction with mass spectrometry

Czech Academy of Sciences Publication Activity Database

Moravcová, Dana; Rantamäki, A. H.; Duša, Filip; Wiedmer, S. K.

2016-01-01

Roč. 37, 7-8 (2016), s. 880-912 ISSN 0173-0835 Institutional support: RVO:68081715 Keywords : capillary electrochromatography * capillary liquid chromatography * mass spec- trometry * monolithic columns Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 2.744, year: 2016

Capillary condensation of short-chain molecules.

Science.gov (United States)

Bryk, Paweł; Pizio, Orest; Sokolowski, Stefan

2005-05-15

A density-functional study of capillary condensation of fluids of short-chain molecules confined to slitlike pores is presented. The molecules are modeled as freely jointed tangent spherical segments with a hard core and with short-range attractive interaction between all the segments. We investigate how the critical parameters of capillary condensation of the fluid change when the pore width decreases and eventually becomes smaller than the nominal linear dimension of the single-chain molecule. We find that the dependence of critical parameters for a fluid of dimers and of tetramers on pore width is similar to that of the monomer fluid. On the other hand, for a fluid of chains consisting of a larger number of segments we observe an inversion effect. Namely, the critical temperature of capillary condensation decreases with increasing pore width for a certain interval of values of the pore width. This anomalous behavior is also influenced by the interaction between molecules and pore walls. We attribute this behavior to the effect of conformational changes of molecules upon confinement.

CAPILLARY BARRIERS IN UNSATURATED FRACTURED ROCKS OF YUCCA MOUNTAIN, NEVADA

International Nuclear Information System (INIS)

Wu, Y.S.; Zhang, W.; Pan, L.; Hinds, J.; Bodvarsson, G.

2000-01-01

This work presents modeling studies investigating the effects of capillary barriers on fluid-flow and tracer-transport processes in the unsaturated zone of Yucca Mountain, Nevada, a potential site for storing high-level radioactive waste. These studies are designed to identify factors controlling the formation of capillary barriers and to estimate their effects on the extent of possible large-scale lateral flow in unsaturated fracture rocks. The modeling approach is based on a continuum formulation of coupled multiphase fluid and tracer transport through fractured porous rock. Flow processes in fractured porous rock are described using a dual-continuum concept. In addition, approximate analytical solutions are developed and used for assessing capillary-barrier effects in fractured rocks. This study indicates that under the current hydrogeologic conceptualization of Yucca Mountain, strong capillary-barrier effects exist for significantly diverting moisture flow

Low internal pressure in femtoliter water capillary bridges reduces evaporation rates.

Science.gov (United States)

Cho, Kun; Hwang, In Gyu; Kim, Yeseul; Lim, Su Jin; Lim, Jun; Kim, Joon Heon; Gim, Bopil; Weon, Byung Mook

2016-03-01

Capillary bridges are usually formed by a small liquid volume in a confined space between two solid surfaces. They can have a lower internal pressure than the surrounding pressure for volumes of the order of femtoliters. Femtoliter capillary bridges with relatively rapid evaporation rates are difficult to explore experimentally. To understand in detail the evaporation of femtoliter capillary bridges, we present a feasible experimental method to directly visualize how water bridges evaporate between a microsphere and a flat substrate in still air using transmission X-ray microscopy. Precise measurements of evaporation rates for water bridges show that lower water pressure than surrounding pressure can significantly decrease evaporation through the suppression of vapor diffusion. This finding provides insight into the evaporation of ultrasmall capillary bridges.

Low internal pressure in femtoliter water capillary bridges reduces evaporation rates

Science.gov (United States)

Cho, Kun; Hwang, In Gyu; Kim, Yeseul; Lim, Su Jin; Lim, Jun; Kim, Joon Heon; Gim, Bopil; Weon, Byung Mook

2016-01-01

Capillary bridges are usually formed by a small liquid volume in a confined space between two solid surfaces. They can have a lower internal pressure than the surrounding pressure for volumes of the order of femtoliters. Femtoliter capillary bridges with relatively rapid evaporation rates are difficult to explore experimentally. To understand in detail the evaporation of femtoliter capillary bridges, we present a feasible experimental method to directly visualize how water bridges evaporate between a microsphere and a flat substrate in still air using transmission X-ray microscopy. Precise measurements of evaporation rates for water bridges show that lower water pressure than surrounding pressure can significantly decrease evaporation through the suppression of vapor diffusion. This finding provides insight into the evaporation of ultrasmall capillary bridges. PMID:26928329

Capillary/myocyte mismatch in the heart in renal failure--a role for erythropoietin?

Science.gov (United States)

Amann, K; Buzello, M; Simonaviciene, A; Miltenberger-Miltenyi, G; Koch, A; Nabokov, A; Gross, M L; Gless, B; Mall, G; Ritz, E

2000-07-01

Chronic renal failure is characterized by remodeling of the heart with left ventricular hypertrophy (increasing oxygen demand) and capillary deficit leading to capillary/myocyte mismatch (decreasing oxygen supply). Erythropoietin (Epo) has known angiogenic properties causing endothelial cell activation, migration and sprouting, mediated at least in part via the JAK/STAT (Janus kinase/signal transducers and activators of transcription) pathway. In uraemic cardiac hypertrophy the presence of diminished capillary supply implies that capillary growth does not keep pace with development of hypertrophy. To investigate whether this was due to a deficit of the angiogenic hormone Epo we examined whether Epo levels are altered and whether an increase in haematocrit by administration of rhEpo influences capillary supply, i.e. capillary/myocyte mismatch in experimental renal failure. Male Spraque-Dawley rats were either subjected to partial renal ablation or sham operation. Only modest amounts of renal tissue were removed so that the rats were not anemic. Subgroups of rats received either human (rh)Epo alone or in combination with unspecific antihypertensive treatment (dihydralazine plus furosemide) in order to control the Epo induced rise in blood pressure. Capillary supply was measured stereologically as capillary length per volume myocardium using the orientator method. Capillary length density was reduced by approximately 25% after partial renal ablation (3237+/-601 vs 4293+/-501 mm/mm(3) in controls). It was not statistically different in animals with partial renal ablation+rhEpo+antihypertensive treatment (3620+/-828 mm/mm(3)) compared to partial ablation alone. The study shows that lack of Epo does not cause, or contribute to, the deficit of capillary growth in the hypertrophied left ventricle of rats with renal failure. In addition, a rise in haematocrit is not accompanied by beneficial effects on alterations of cardiovascular structure in experimental renal failure.

Capillary-induced crack healing between surfaces of nanoscale roughness.

Science.gov (United States)

Soylemez, Emrecan; de Boer, Maarten P

2014-10-07

Capillary forces are important in nature (granular materials, insect locomotion) and in technology (disk drives, adhesion). Although well studied in equilibrium state, the dynamics of capillary formation merit further investigation. Here, we show that microcantilever crack healing experiments are a viable experimental technique for investigating the influence of capillary nucleation on crack healing between rough surfaces. The average crack healing velocity, v̅, between clean hydrophilic polycrystalline silicon surfaces of nanoscale roughness is measured. A plot of v̅ versus energy release rate, G, reveals log-linear behavior, while the slope |d[log(v̅)]/dG| decreases with increasing relative humidity. A simplified interface model that accounts for the nucleation time of water bridges by an activated process is developed to gain insight into the crack healing trends. This methodology enables us to gain insight into capillary bridge dynamics, with a goal of attaining a predictive capability for this important microelectromechanical systems (MEMS) reliability failure mechanism.

A Chip-Capillary Hybrid Device for Automated Transfer of Sample Pre-Separated by Capillary Isoelectric Focusing to Parallel Capillary Gel Electrophoresis for Two-Dimensional Protein Separation

Science.gov (United States)

Lu, Joann J.; Wang, Shili; Li, Guanbin; Wang, Wei; Pu, Qiaosheng; Liu, Shaorong

2012-01-01

In this report, we introduce a chip-capillary hybrid device to integrate capillary isoelectric focusing (CIEF) with parallel capillary sodium dodecyl sulfate – polyacrylamide gel electrophoresis (SDS-PAGE) or capillary gel electrophoresis (CGE) toward automating two-dimensional (2D) protein separations. The hybrid device consists of three chips that are butted together. The middle chip can be moved between two positions to re-route the fluidic paths, which enables the performance of CIEF and injection of proteins partially resolved by CIEF to CGE capillaries for parallel CGE separations in a continuous and automated fashion. Capillaries are attached to the other two chips to facilitate CIEF and CGE separations and to extend the effective lengths of CGE columns. Specifically, we illustrate the working principle of the hybrid device, develop protocols for producing and preparing the hybrid device, and demonstrate the feasibility of using this hybrid device for automated injection of CIEF-separated sample to parallel CGE for 2D protein separations. Potentials and problems associated with the hybrid device are also discussed. PMID:22830584

On hydraulics of capillary tubes

Directory of Open Access Journals (Sweden)

N.G. Aloyan

2016-03-01

Full Text Available The article considers the laws of motion of water in the capillary tubes, taken as a model for flowing well, on the analogical net count device. For capillary tube the lower limit value of flow rate is empirically determined above which the total hydraulic resistance of the capillary is practically constant. The specificity of the phenomenon is that the regime of motion, by a Reynolds number, for a given flow rate still remains laminar. This circumstance can perplex the specialists, so the author invites them to the scientific debate on the subject of study. Obviously, to identify the resulting puzzle it is necessary to conduct a series of experiments using capillaries of different lengths and diameters and with different values of overpressure. The article states that in tubes with very small diameter the preliminary magnitude of capillary rise of water in the presence of flow plays no role and can be neglected.

Western blotting using capillary electrophoresis.

Science.gov (United States)

Anderson, Gwendolyn J; M Cipolla, Cynthia; Kennedy, Robert T

2011-02-15

A microscale Western blotting system based on separating sodium-dodecyl sulfate protein complexes by capillary gel electrophoresis followed by deposition onto a blotting membrane for immunoassay is described. In the system, the separation capillary is grounded through a sheath capillary to a mobile X-Y translation stage which moves a blotting membrane past the capillary outlet for protein deposition. The blotting membrane is moistened with a methanol and buffer mixture to facilitate protein adsorption. Although discrete protein zones could be detected, bands were broadened by ∼1.7-fold by transfer to membrane. A complete Western blot for lysozyme was completed in about one hour with 50 pg mass detection limit from low microgram per milliliter samples. These results demonstrate substantial reduction in time requirements and improvement in mass sensitivity compared to conventional Western blots. Western blotting using capillary electrophoresis shows promise to analyze low volume samples with reduced reagents and time, while retaining the information content of a typical Western blot.

Nasal Lobular Capillary Hemangioma

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Prashant Patil

2013-01-01

Full Text Available Nasal lobular capillary hemangioma is a rare benign tumor of the paranasal sinuses. This lesion is believed to grow rapidly in size over time. The exact etiopathogenesis is still a dilemma. We discuss a case of nasal lobular capillary hemangioma presenting with a history of epistaxis. Contrast enhanced computed tomography of paranasal sinuses revealed an intensely enhancing soft-tissue mass in the left nasal cavity and left middle and inferior meati with no obvious bony remodeling or destruction. We present imaging and pathologic features of nasal lobular capillary hemangioma and differentiate it from other entities like nasal angiofibroma.

[Is the use of plastic capillary tubes justified for blood gases analysis?].

Science.gov (United States)

Daurès, Marie-Françoise; Bozonnat, Marie-Cécile; Cristol, Jean-Paul

2011-01-01

Some clinical units, such as neonatal or maternity units, preferentially use capillary tubes when analysing blood gases. Using glass tubes is delicate and nurses must recollect blood when breaking. In order to eliminate this problem, we tested flexible, plastic capillary tubes in both the above mentionned units and in our biochemistry laboratory. Each unit, where glass tubes were habitually used, tested 200 flexible, plastic capillary tubes. In addition, the nursing staffed filled out a questionnaire concerned tube usage. Both units clearly preferred using the flexible tubes. In the laboratory, results for blood gas analyses were compared between rigid glass and flexible plastic capillary tubes for 112 patients. Concordance tests did not showed significant differences between the two tube types, except for hematocrit and total haemoglobin. A questionnaire was also presented to the lab technician, who confirmed the easier usability of plastic capillary tubes.

Modeling aerobic biodegradation in the capillary fringe.

Science.gov (United States)

Luo, Jian; Kurt, Zohre; Hou, Deyi; Spain, Jim C

2015-02-03

Vapor intrusion from volatile subsurface contaminants can be mitigated by aerobic biodegradation. Laboratory column studies with contaminant sources of chlorobenzene and a mixture of chlorobenzene, 1,2-dichlorobenzene, and 1,4-dichlorobenzene showed that contaminants were rapidly degraded in thin reactive zones with high biomass and low substrate concentrations in the vicinity of the capillary fringe. Such behavior was well characterized by a model that includes oxygen-, substrate-, and biomass-dependent biodegradation kinetics along with diffusive transport processes. An analytical solution was derived to provide theoretical support for the simplification of reaction kinetics and the approximation of reactive zone location and mass flux relationships at steady state. Results demonstrate the potential of aerobic natural attenuation in the capillary fringe for preventing contaminant migration in the unsaturated zone. The solution indicates that increasing contaminant mass flux into the column creates a thinner reactive zone and pushes it toward the oxygen boundary, resulting in a shorter distance to the oxygen source and a larger oxygen mass flux that balances the contaminant mass flux. As a consequence, the aerobic biodegradation can reduce high contaminant concentrations to low levels within the capillary fringe and unsaturated zone. The results are consistent with the observations of thin reactive layers at the interface in unsaturated zones. The model considers biomass while including biodegradation in the capillary fringe and unsaturated zone and clearly demonstrates that microbial communities capable of using the contaminants as electron donors may lead to instantaneous degradation kinetics in the capillary fringe and unsaturated zone.

Factors affecting the separation performance of proteins in capillary electrophoresis.

Science.gov (United States)

Zhu, Yueping; Li, Zhenqing; Wang, Ping; Shen, Lisong; Zhang, Dawei; Yamaguchi, Yoshinori

2018-04-15

Capillary electrophoresis (CE) is an effective tool for protein separation and analysis. Compared with capillary gel electrophoresis (CGE), non-gel sieving capillary electrophoresis (NGSCE) processes the superiority on operation, repeatability and automaticity. Herein, we investigated the effect of polymer molecular weight and concentration, electric field strength, and the effective length of the capillary on the separation performance of proteins, and find that (1) polymer with high molecular weight and concentration favors the separation of proteins, although concentrated polymer hinders its injection into the channel of the capillary due to its high viscosity. (2) The resolution between the adjacent proteins decreases with the increase of electric field strength. (3) When the effective length of the capillary is long, the separation performance improves at the cost of separation time. (4) 1.4% (w/v) hydroxyethyl cellulose (HEC), 100 V/cm voltage and 12 cm effective length offers the best separation for the proteins with molecular weight from 14,400 Da to 97,400 Da. Finally, we employed the optimal electrophoretic conditions to resolve Lysozyme, Ovalbumin, BSA and their mixtures, and found that they were baseline resolved within 15 min. Copyright © 2018 Elsevier B.V. All rights reserved.

Changes in labial capillary density on ascent to and descent from high altitude [version 1; referees: 2 approved

Directory of Open Access Journals (Sweden)

Edward Gilbert-Kawai

2016-08-01

Full Text Available Present knowledge of how the microcirculation is altered by prolonged exposure to hypoxia at high altitude is incomplete and modification of existing analytical techniques may improve our knowledge considerably. We set out to use a novel simplified method of measuring in vivo capillary density during an expedition to high altitude using a CytoCam incident dark field imaging video-microscope. The simplified method of data capture involved recording one-second images of the mucosal surface of the inner lip to reveal data about microvasculature density in ten individuals. This was done on ascent to, and descent from, high altitude. Analysis was conducted offline by two independent investigators blinded to the participant identity, testing conditions and the imaging site.  Additionally we monitored haemoglobin concentration and haematocrit data to see if we could support or refute mechanisms of altered density relating to vessel recruitment. Repeated sets of paired values were compared using Kruskall Wallis Analysis of Variance tests, whilst comparisons of values between sites was by related samples Wilcoxon Signed Rank Test. Correlation between different variables was performed using Spearman’s rank correlation coefficient, and concordance between analysing investigators using intra-class correlation coefficient. There was a significant increase in capillary density from London on ascent to high altitude; median capillaries per field of view area increased from 22.8 to 25.3 (p=0.021. There was a further increase in vessel density during the six weeks spent at altitude (25.3 to 32.5, p=0.017. Moreover, vessel density remained high on descent to Kathmandu (31.0 capillaries per field of view area, despite a significant decrease in haemoglobin concentration and haematocrit. Using a simplified technique, we have demonstrated an increase in capillary density on early and sustained exposure to hypobaric hypoxia at thigh altitude, and that this remains

Capillary waves in slow motion

International Nuclear Information System (INIS)

Seydel, Tilo; Tolan, Metin; Press, Werner; Madsen, Anders; Gruebel, Gerhard

2001-01-01

Capillary wave dynamics on glycerol surfaces has been investigated by means of x-ray photon correlation spectroscopy performed at grazing angles. The measurements show that thermally activated capillary wave motion is slowed down exponentially when the sample is cooled below 273 K. This finding directly reflects the freezing of the surface waves. The wave-number dependence of the measured time constants is in quantitative agreement with theoretical predictions for overdamped capillary waves

Direct Printing of Stretchable Elastomers for Highly Sensitive Capillary Pressure Sensors.

Science.gov (United States)

Liu, Wenguang; Yan, Chaoyi

2018-03-28

We demonstrate the successful fabrication of highly sensitive capillary pressure sensors using an innovative 3D printing method. Unlike conventional capacitive pressure sensors where the capacitance changes were due to the pressure-induced interspace variations between the parallel plate electrodes, in our capillary sensors the capacitance was determined by the extrusion and extraction of liquid medium and consequent changes of dielectric constants. Significant pressure sensitivity advances up to 547.9 KPa -1 were achieved. Moreover, we suggest that our innovative capillary pressure sensors can adopt a wide range of liquid mediums, such as ethanol, deionized water, and their mixtures. The devices also showed stable performances upon repeated pressing cycles. The direct and versatile printing method combined with the significant performance advances are expected to find important applications in future stretchable and wearable electronics.

Comprehensive protein profiling by multiplexed capillary zone electrophoresis using cross-linked polyacrylamide coated capillaries.

Science.gov (United States)

Liu, Shaorong; Gao, Lin; Pu, Qiaosheng; Lu, Joann J; Wang, Xingjia

2006-02-01

We have recently developed a new process to create cross-linked polyacrylamide (CPA) coatings on capillary walls to suppress protein-wall interactions. Here, we demonstrate CPA-coated capillaries for high-efficiency (>2 x 10(6) plates per meter) protein separations by capillary zone electrophoresis (CZE). Because CPA virtually eliminates electroosmotic flow, positive and negative proteins cannot be analyzed in a single run. A "one-sample-two-separation" approach is developed to achieve a comprehensive protein analysis. High throughput is achieved through a multiplexed CZE system.

PAL application to the study of sorption mechanism in polymers - capillary effects

International Nuclear Information System (INIS)

Ito, Y.; Shimadzu, A.; Ikeda, K.

1999-01-01

The positron annihilation lifetime technique can be applied to the study of the sorption mechanism in polymers in a quite unique way. In our previous experiments it had been shown that τ 3 and I 3 of polymers show a V-shaped dependence as a function of the contact with vapours. The decreasing part of the V-shaped dependence had been attributed to the Langmuir-type sorption, and the increasing part of delayed occurrence of the Henry-type sorption. But since there was some doubt that the capillary effect, i.e. the vapour to be sorbed is deposited in between the polymer membranes, might be involved in the increasing part, we performed a careful experiment to avoid the capillary effect. We have performed further experiments in a careful conditions to avoid the capillary effect, and have observed the same V-shape as before. Thus our interpretation of the V-shaped dependence has been established. Furthermore, in another example it is shown a case where the capillary effect is observed. This latter case is an example how positron annihilation lifetime can distinguish the real sorption and false sorption (capillary effect). (author)

Enhanced oxygen delivery induced by perfluorocarbon emulsions in capillary tube oxygenators.

Science.gov (United States)

Vaslef, S N; Goldstick, T K

1994-01-01

Previous studies showed that a new generation of perfluorocarbon (PFC) emulsions increased tissue PO2 in the cat retina to a degree that could not be explained by the small increase in arterial O2 content seen after the infusion of low doses of 1 g PFC/kg body weight. It seems that increased O2 delivery at the tissue level after PFC infusion is caused by a local effect in the microcirculation. The authors studies this effect in vitro at steady state in a closed loop circuit, consisting of one of two types of capillary tube oxygenators, deoxygenator(s), a reservoir bag filled with anticoagulated bovine blood or saline (control), and a roller pump, to see if the addition of PFC would have an effect on the PO2 difference (delta PO2) across the capillary tube membrane oxygenator at a blood flow rate of 3 l/min. Perfluorocarbon was added in three incremental doses, each giving about 0.7 vol% of PFC. The delta PO2 across the oxygenator was measured before and after each dose. The mean percent increases in delta PO2 in blood for two types of oxygenators were 19.2 +/- 8% (mean +/- SD, n = 6, P = 0.002) and 9.9 +/- 4% (n = 3, P = 0.05), respectively, whereas the mean percent change in delta PO2 in saline was -4.9 +/- 2% (n = 2, P = 0.2). Inlet PO2s to the oxygenator were only minimally increased. The authors conclude that O2 delivery was significantly enhanced after injection of PFC in blood in this capillary tube model. A near wall excess of PFC particles may account for the augmentation of O2 diffusion in this model.

DNA typing by capillary electrophoresis

Energy Technology Data Exchange (ETDEWEB)

Zhang, N.

1997-10-08

Capillary electrophoresis is becoming more and more important in nucleic acid analysis including DNA sequencing, typing and disease gene measurements. This work summarized the background of DNA typing. The recent development of capillary electrophoresis was also discussed. The second part of the thesis showed the principle of DNA typing based on using the allelic ladder as the absolute standard ladder in capillary electrophoresis system. Future work will be focused on demonstrating DNA typing on multiplex loci and examples of disease diagnosis in the on-line format of PCR-CE. Also capillary array electrophoresis system should allow high throughput, fast speed DNA typing. Only the introduction and conclusions for this report are available here. A reprint was removed for separate processing.

Bacterial surface layer proteins as a novel capillary coating material for capillary electrophoretic separations

Energy Technology Data Exchange (ETDEWEB)

Moreno-Gordaliza, Estefanía, E-mail: emorenog@ucm.es [Division of Analytical Biosciences, Leiden Academic Centre for Drug Research, Universiteit Leiden, Einsteinweg 55, 2300, RA, Leiden (Netherlands); Department of Analytical Chemistry, Faculty of Chemistry, Universidad Complutense de Madrid, Avda. Complutense s/n, 28040, Madrid (Spain); Stigter, Edwin C.A. [Division of Analytical Biosciences, Leiden Academic Centre for Drug Research, Universiteit Leiden, Einsteinweg 55, 2300, RA, Leiden (Netherlands); Department of Molecular Cancer Research, Universitair Medisch Centrum Utrecht, Wilhelmina Kinder Ziekenhuis, Lundlaan 6, 3584, EA Utrecht (Netherlands); Lindenburg, Petrus W.; Hankemeier, Thomas [Division of Analytical Biosciences, Leiden Academic Centre for Drug Research, Universiteit Leiden, Einsteinweg 55, 2300, RA, Leiden (Netherlands)

2016-06-07

A novel concept for stable coating in capillary electrophoresis, based on recrystallization of surface layer proteins on hydrophobized fused silica capillaries, was demonstrated. Surface layer protein A (SlpA) from Lactobacillus acidophilus bacteria was extracted, purified and used for coating pre-silanized glass substrates presenting different surface wettabilities (either hydrophobic or hydrophilic). Contact angle determination on SlpA-coated hydrophobic silica slides showed that the surfaces turned to hydrophilic after coating (53 ± 5°), due to a protein monolayer formation by protein-surface hydrophobic interactions. Visualization by atomic force microscopy demonstrated the presence of a SlpA layer on methylated silica slides displaying a surface roughness of 0.44 ± 0.02 nm. Additionally, a protein layer was visualized by fluorescence microscopy in methylated silica capillaries coated with SlpA and fluorescein isothiocyanate-labeled. The SlpA-coating showed an outstanding stability, even after treatment with 20 mM NaOH (pH 12.3). The electroosmotic flow in coated capillaries showed a partial suppression at pH 7.50 (3.8 ± 0.5 10{sup −9} m{sup 2} V{sup −1} s{sup −1}) when compared with unmodified fused silica (5.9 ± 0.1 10{sup −8} m{sup 2} V{sup −1} s{sup −1}). To demonstrate the potential of this novel coating, the SlpA-coated capillaries were applied for the first time for electrophoretic separation, and proved to be very suitable for the isotachophoretic separation of lipoproteins in human serum. The separations showed a high degree of repeatability (absolute migration times with 1.1–1.8% coefficient-of-variation (CV) within a day) and 2–3% CV inter-capillary reproducibility. The capillaries were stable for more than 100 runs at pH 9.40, and showed to be an exceptional alternative for challenging electrophoretic separations at long-term use. - Highlights: • New coating using recrystallized surface-layer proteins on

Capillary pressure - saturation relations in quartz and carbonate sands: Limitations for correlating capillary and wettability influences on air, oil, and supercritical CO2 trapping

Science.gov (United States)

Tokunaga, T. K.; Wang, S.; Wan, J.; Dong, W.; Kim, Y.

2016-12-01

Capillary pressure (Pc) - saturation (Sw) relations are essential for predicting equilibrium and flow of immiscible fluid pairs in soils and deeper geologic formations. In systems that are difficult to measure, behavior is often estimated based on capillary scaling of easily measured Pc-Sw relations (e.g., air-water, and oil-water), yet the reliability of such approximations needs to be examined. In this study, seventeen sets of brine drainage and imbibition curves were measured with air-brine, decane-brine, and supercritical (sc) CO2-brine in homogeneous quartz and carbonate sands, using porous plate systems under ambient (0.1 MPa, 23 °C) and reservoir (12.0 MPa, 45 °C) conditions. Comparisons between these measurements showed significant differences in residual nonwetting phase saturation, Snw,r. Through applying capillary scaling, changes in interfacial properties were indicated, particularly wettability. With respect to the residual trapping of the nonwetting phases, Snwr, CO2 > Snwr, decane > Snwr, air. Decane-brine and scCO2-brine Pc-Sw curves deviated significantly from predictions assuming hydrophilic interactions. Moreover, neither the scaled capillary behavior nor Snw,r for scCO2-brine were well represented by decane-brine, apparently because of differences in wettability and viscosities, indicating limitations for using decane (and other organic liquids) as a surrogate fluid in studies intended to apply to geological carbon sequestration. Thus, challenges remain in applying scaling for predicting capillary trapping and multiphase displacement processes across such diverse fields as vadose zone hydrology, enhanced oil recovery, and geologic carbon sequestration.

Capillary Condensation in Confined Media

OpenAIRE

Charlaix, Elisabeth; Ciccotti, Matteo

2009-01-01

28 pages - To appear in 2010 in the Handbook of Nanophysics - Vol 1 - Edited by Klaus Sattler - CRC Press; We review here the physics of capillary condensation of liquids in confined media, with a special regard to the application in nanotechnologies. The thermodynamics of capillary condensation and thin film adsorption are first exposed along with all the relevant notions. The focus is then shifted to the modelling of capillary forces, to their measurements techniques (including SFA, AFM and...

Capillary-Condenser-Pumped Heat-Transfer Loop

Science.gov (United States)

Silverstein, Calvin C.

1989-01-01

Heat being transferred supplies operating power. Capillary-condenser-pumped heat-transfer loop similar to heat pipe and to capillary-evaporator-pumped heat-transfer loop in that heat-transfer fluid pumped by evaporation and condensation of fluid at heat source and sink, respectively. Capillary condenser pump combined with capillary evaporator pump to form heat exchanger circulating heat-transfer fluids in both loops. Transport of heat more nearly isothermal. Thermal stress in loop reduced, and less external surface area needed in condenser section for rejection of heat to heat sink.

Performance of soft x-ray laser pumped by capillary discharge

International Nuclear Information System (INIS)

Sakai, Yusuke; Kakuya, Yuji; Xiao, Yifan

2005-01-01

We report the output characteristics of capillary discharge single-pass 46.9 nm Ne-like Ar soft-X-ray laser generated by a capillary z-pinch discharge. The coherence properties of the laser have shown to be improved with the increase of the length of laser amplifier from 20 up to 35 cm. The high degree of the spatial coherence of the laser beam produced by 35 cm long capillary is demonstrated by the results obtained in a classical Young's double-slit experiments. We found that the coherence length of the laser is 50 μm. For the 20 cm-long capillary, the diameter of a laser beam is in a range from 3.2 to 4.0 mm, which is corresponding to a range of divergence from 2.2 to 2.8 mrad. Finally, we introduce two spikes on X-ray diode (XRD) signal observed in a single shot. (author)

Phase Behaviors of Reservoir Fluids with Capillary Eff ect Using Particle Swarm Optimization

KAUST Repository

Ma, Zhiwei

2013-05-06

The study of phase behavior is important for the oil and gas industry. Many approaches have been proposed and developed for phase behavior calculation. In this thesis, an alternative method is introduced to study the phase behavior by means of minimization of Helmholtz free energy. For a system at fixed volume, constant temperature and constant number of moles, the Helmholtz free energy reaches minimum at the equilibrium state. Based on this theory, a stochastic method called Particle Swarm Optimization (PSO) algorithm, is implemented to compute the phase diagrams for several pure component and mixture systems. After comparing with experimental and the classical PT-ash calculation, we found the phase diagrams obtained by minimization of the Helmholtz Free Energy approach match the experimental and theoretical diagrams very well. Capillary effect is also considered in this thesis because it has a significant influence on the phase behavior of reservoir fluids. In this part, we focus on computing the phase envelopes, which consists of bubble and dew point lines. Both fixed and calculated capillary pressure from the Young-Laplace equation cases are introduced to study their effects on phase envelopes. We found that the existence of capillary pressure will change the phase envelopes. Positive capillary pressure reduces the dew point and bubble point temperatures under the same pressure condition, while the negative capillary pressure increases the dew point and bubble point temperatures. In addition, the change of contact angle and pore radius will affect the phase envelope. The effect of the pore radius on the phase envelope is insignificant when the radius is very large. These results may become reference for future research and study. Keywords: Phase Behavior; Particle Swarm Optimization; Capillary Pressure; Reservoir Fluids; Phase Equilibrium; Phase Envelope.

Phase Behaviors of Reservoir Fluids with Capillary Eff ect Using Particle Swarm Optimization

KAUST Repository

Ma, Zhiwei

2013-01-01

The study of phase behavior is important for the oil and gas industry. Many approaches have been proposed and developed for phase behavior calculation. In this thesis, an alternative method is introduced to study the phase behavior by means of minimization of Helmholtz free energy. For a system at fixed volume, constant temperature and constant number of moles, the Helmholtz free energy reaches minimum at the equilibrium state. Based on this theory, a stochastic method called Particle Swarm Optimization (PSO) algorithm, is implemented to compute the phase diagrams for several pure component and mixture systems. After comparing with experimental and the classical PT-ash calculation, we found the phase diagrams obtained by minimization of the Helmholtz Free Energy approach match the experimental and theoretical diagrams very well. Capillary effect is also considered in this thesis because it has a significant influence on the phase behavior of reservoir fluids. In this part, we focus on computing the phase envelopes, which consists of bubble and dew point lines. Both fixed and calculated capillary pressure from the Young-Laplace equation cases are introduced to study their effects on phase envelopes. We found that the existence of capillary pressure will change the phase envelopes. Positive capillary pressure reduces the dew point and bubble point temperatures under the same pressure condition, while the negative capillary pressure increases the dew point and bubble point temperatures. In addition, the change of contact angle and pore radius will affect the phase envelope. The effect of the pore radius on the phase envelope is insignificant when the radius is very large. These results may become reference for future research and study. Keywords: Phase Behavior; Particle Swarm Optimization; Capillary Pressure; Reservoir Fluids; Phase Equilibrium; Phase Envelope.

Alterations in the muscle-to-capillary interface in patients with different degrees of chronic obstructive pulmonary disease

Directory of Open Access Journals (Sweden)

Abdel-Halim Samy M

2010-07-01

Full Text Available Abstract Background It is hypothesized that decreased capillarization of limb skeletal muscle is implicated in the decreased exercise tolerance in COPD patients. We have recently demonstrated decreased number of capillaries per muscle fibre (CAF but no changes in CAF in relation to fibre area (CAFA, which is based on the diffusion distance between the capillary and muscle fibre. The aim of the current study is to investigate the muscle-to-capillary interface which is an important factor involved in oxygen supply to the muscle that has previously been suggested to be a more sensitive marker for changes in the capillary bed compared to CAF and CAFA. Methods 23 COPD patients and 12 age-matched healthy subjects participated in the study. Muscle-to-capillary interface was assessed in muscle biopsies from the tibialis anterior muscle using the following parameters: 1 The capillary-to-fibre ratio (C:Fi which is defined as the sum of the fractional contributions of all capillary contacts around the fibre 2 The ratio between C:Fi and the fibre perimeter (CFPE-index 3 The ratio between length of capillary and fibre perimeter (LC/PF which is also referred to as the index of tortuosity. Exercise capacity was determined using the 6-min walking test. Results A positive correlation was found between CFPE-index and ascending disease severity with CFPE-index for type I fibres being significantly lower in patients with moderate and severe COPD. Furthermore, a positive correlation was observed between exercise capacity and CFPE-index for both type I and type IIa fibres. Conclusion It can be concluded that the muscle-to-capillary interface is disturbed in the tibialis anterior muscle in patients with COPD and that interface is strongly correlated to increased disease severity and to decreased exercise capacity in this patient group.

Pulmonary diffusing capacity, capillary blood volume, and cardiac output during sustained microgravity

Science.gov (United States)

Prisk, G. K.; Guy, Harold J. B.; Elliott, Ann R.; Deutschman, Robert A., III; West, John B.

1993-01-01

We measured pulmonary diffusing capacity (DL), diffusing capacity per unit lung volume, pulmonary capillary blood volume (Vc), membrane diffusing capacity (Dm), pulmonary capillary blood flow or cardiac output (Qc), and cardiac stroke volume (SV) in four subjects exposed to nine days of microgravity. DL in microgravity was elevated compared with preflight standing values and was higher than preflight supine because of the elevation of both Vc and Dm. The elevation in Vc was comparable to that measured supine in 1 G, but the increase in Dm was in sharp contrast to the supine value. We postulate that, in 0 G, pulmonary capillary blood is evenly distributed throughout the lung, providing for uniform capillary filling, leading to an increase in the surface area available for diffusion. By contrast, in the supine 1-G state, the capillaries are less evenly filled, and although a similar increase in blood volume is observed, the corresponding increase in surface area does not occur. DL and its subdivisions showed no adaptive changes from the first measurement 24 h after the start of 0 G to eight days later. Similarly, there were no trends in the postflight data, suggesting that the principal mechanism of these changes was gravitational. The increase in Dm suggests that subclinical pulmonary edema did not result from exposure to 0 G. Qc was modestly increased inflight and decreased postflight compared with preflight standing. Compared with preflight standing, SV was increased 46 percent inflight and decreased 14 percent in the 1st week postflight. There were temporal changes in Qc and SV during 0 G, with the highest values recorded at the first measurement, 24 h into the flight. The lowest values of Qc and SV occurred on the day of return.

Correlation between enhancement characteristics of MR mammography and capillary density of breast lesions

International Nuclear Information System (INIS)

Poellinger, Alexander; El-Ghannam, Sahra; Diekmann, Susanne; Fischer, Thomas; Kristiansen, Glen; Fritzsche, Florian; Fallenberg, Eva; Morawietz, Lars; Diekmann, Felix

2014-01-01

Highlights: • We correlate capillary density of breast lesions with MRM. • Capillary density correlates with tumor enhancement for all lesions. • However no such correlation exists for the malignant or benign groups separately. • Mean vessel number of lymphatic vessels do not correlate with tumor enhancement.These results might be of help in the workup of MR-guided breast biopsies. • These results might be of help in the workup of MR-guided breast biopsies. - Abstract: Objective: To correlate capillary density of breast lesions using the markers D2-40, CD31, and CD34 with early and late enhancement of magnetic resonance mammography (MRM). Materials and methods: The local ethics committee approved this study, and informed consent was available from all patients. The study included 64 women with 66 histologically proven breast lesions (41 malignant, 25 benign). MR-enhancement 1 min after contrast medium administration was determined in the tumor (I t1 /I t0 ratio) and in comparison to the surrounding tissue (I t1 /I t1-fat ratio). Capillary density was quantified based on immunohistological staining with D2-40, CD31, and CD34 in breast tumors and surrounding breast tissue. Mean capillary densities were correlated with contrast enhancement in the tumor and surrounding breast tissue. The Kruskal–Wallis test was used to test whether lesions with different MR enhancement patterns differed in terms of capillary density. Results: For CD34, there was statistically significant correlation between capillary density and tumor enhancement (r = 0.329, p = 0.012), however not for the malignant or benign groups separately. Mean vessel number identified by staining with D2-40 and CD31 did not correlate significantly with tumor enhancement (D2-40: r = −0.188, p = 0.130; CD31: r = 0.095, p = 0.448). There were no statistically significant differences in capillary density between breast lesions with delayed enhancement or a plateau and lesions showing washout (Kruskal�

Correlation between enhancement characteristics of MR mammography and capillary density of breast lesions

Energy Technology Data Exchange (ETDEWEB)

Poellinger, Alexander, E-mail: alexander.poellinger@charite.de [Charité, Universitätsmedizin Berlin, Department of Radiology, Augustenburger Platz 1, 13353 Berlin (Germany); El-Ghannam, Sahra; Diekmann, Susanne; Fischer, Thomas [Charité, Universitätsmedizin Berlin, Department of Radiology, Augustenburger Platz 1, 13353 Berlin (Germany); Kristiansen, Glen [Universitätsklinikum Bonn, Department of Pathology, Sigmund-Freud-Str. 25, D-53127 Bonn (Germany); Fritzsche, Florian [Institut für Histologie und Zytologie, Bahnhofplatz 11, Postfach, 9101 Herisau (Switzerland); Fallenberg, Eva [Charité, Universitätsmedizin Berlin, Department of Radiology, Augustenburger Platz 1, 13353 Berlin (Germany); Morawietz, Lars [Diagnostik Ernst von Bergmann GmbH, Charlottenstr. 72, 14467 Potsdam (Germany); Diekmann, Felix [Charité, Universitätsmedizin Berlin, Department of Radiology, Augustenburger Platz 1, 13353 Berlin (Germany)

2014-12-15

Highlights: • We correlate capillary density of breast lesions with MRM. • Capillary density correlates with tumor enhancement for all lesions. • However no such correlation exists for the malignant or benign groups separately. • Mean vessel number of lymphatic vessels do not correlate with tumor enhancement.These results might be of help in the workup of MR-guided breast biopsies. • These results might be of help in the workup of MR-guided breast biopsies. - Abstract: Objective: To correlate capillary density of breast lesions using the markers D2-40, CD31, and CD34 with early and late enhancement of magnetic resonance mammography (MRM). Materials and methods: The local ethics committee approved this study, and informed consent was available from all patients. The study included 64 women with 66 histologically proven breast lesions (41 malignant, 25 benign). MR-enhancement 1 min after contrast medium administration was determined in the tumor (I{sub t1}/I{sub t0} ratio) and in comparison to the surrounding tissue (I{sub t1}/I{sub t1-fat} ratio). Capillary density was quantified based on immunohistological staining with D2-40, CD31, and CD34 in breast tumors and surrounding breast tissue. Mean capillary densities were correlated with contrast enhancement in the tumor and surrounding breast tissue. The Kruskal–Wallis test was used to test whether lesions with different MR enhancement patterns differed in terms of capillary density. Results: For CD34, there was statistically significant correlation between capillary density and tumor enhancement (r = 0.329, p = 0.012), however not for the malignant or benign groups separately. Mean vessel number identified by staining with D2-40 and CD31 did not correlate significantly with tumor enhancement (D2-40: r = −0.188, p = 0.130; CD31: r = 0.095, p = 0.448). There were no statistically significant differences in capillary density between breast lesions with delayed enhancement or a plateau and lesions showing

Validation of capillary blood analysis and capillary testing mode on the epoc Point of Care system

Directory of Open Access Journals (Sweden)

Jing Cao

2017-12-01

Full Text Available Background: Laboratory test in transport is a critical component of patient care, and capillary blood is a preferred sample type particularly in children. This study evaluated the performance of capillary blood testing on the epoc Point of Care Blood Analysis System (Alere Inc. Methods: Ten fresh venous blood samples was tested on the epoc system under the capillary mode. Correlation with GEM 4000 (Instrumentation Laboratory was examined for Na+, K+, Cl-, Ca2+, glucose, lactate, hematocrit, hemoglobin, pO2, pCO2, and pH, and correlation with serum tested on Vitros 5600 (Ortho Clinical Diagnostics was examined for creatinine. Eight paired capillary and venous blood was tested on epoc and ABL800 (Radiometer for the correlation of Na+, K+, Cl-, Ca2+, glucose, lactate, hematocrit, hemoglobin, pCO2, and pH. Capillary blood from 23 apparently healthy volunteers was tested on the epoc system to assess the concordance to reference ranges used locally. Results: Deming regression correlation coefficients for all the comparisons were above 0.65 except for ionized Ca2+. Accordance of greater than 85% to the local reference ranges were found in all assays with the exception of pO2 and Cl-. Conclusion: Data from this study indicates that capillary blood tests on the epoc system provide comparable results to reference method for these assays, Na+, K+, glucose, lactate, hematocrit, hemoglobin, pCO2, and pH. Further validation in critically ill patients is needed to implement the epoc system in patient transport. Impact of the study: This study demonstrated that capillary blood tests on the epoc Point of Care Blood Analysis System give comparable results to other chemistry analyzers for major blood gas and critical tests. The results are informative to institutions where pre-hospital and inter-hospital laboratory testing on capillary blood is a critical component of patient point of care testing. Keywords: Epoc, Capillary, Transport, Blood gas, Point of care

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

Directory of Open Access Journals (Sweden)

Linmu Chen

2017-11-01

Full Text Available 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.

Microfluidic PMMA interfaces for rectangular glass capillaries

International Nuclear Information System (INIS)

Evander, Mikael; Tenje, Maria

2014-01-01

We present the design and fabrication of a polymeric capillary fluidic interface fabricated by micro-milling. The design enables the use of glass capillaries with any kind of cross-section in complex microfluidic setups. We demonstrate two different designs of the interface; a double-inlet interface for hydrodynamic focusing and a capillary interface with integrated pneumatic valves. Both capillary interfaces are presented together with examples of practical applications. This communication shows the design optimization and presents details of the fabrication process. The capillary interface opens up for the use of complex microfluidic systems in single-use glass capillaries. They also enable simple fabrication of glass/polymer hybrid devices that can be beneficial in many research fields where a pure polymer chip negatively affects the device's performance, e.g. acoustofluidics. (technical note)

Hollow-core revolver fibre with a double-capillary reflective cladding

Energy Technology Data Exchange (ETDEWEB)

Kosolapov, A F; Alagashev, G K; Kolyadin, A N; Pryamikov, A D; Dianov, E M [Fiber Optics Research Center, Russian Academy of Sciences, Moscow (Russian Federation); Biryukov, A S; Bufetov, I A [Moscow Institute of Physics and Technology (State University), Dolgoprudnyi, Moscow Region (Russian Federation)

2016-03-31

We report the fabrication of the first hollow-core revolver fibre with a core diameter as small as 25 μm and an optical loss no higher than 75 dB km{sup -1} at a wavelength of 1850 nm. The decrease in core diameter, with no significant increase in optical loss, is due to the use of double nested capillaries in the reflective cladding design. A number of technical problems pertaining to the fabrication of such fibres are resolved. (fiber optics)

A complete soil hydraulic model accounting for capillary and adsorptive water retention, capillary and film conductivity, and hysteresis

NARCIS (Netherlands)

Sakai, Masaru; Van Genuchten, Martinus Th|info:eu-repo/dai/nl/31481518X; Alazba, A. A.; Setiawan, Budi Indra; Minasny, Budiman

2015-01-01

A soil hydraulic model that considers capillary hysteretic and adsorptive water retention as well as capillary and film conductivity covering the complete soil moisture range is presented. The model was obtained by incorporating the capillary hysteresis model of Parker and Lenhard into the hydraulic

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

Science.gov (United States)

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.

Validation of capillary blood analysis and capillary testing mode on the epoc Point of Care system.

Science.gov (United States)

Cao, Jing; Edwards, Rachel; Chairez, Janette; Devaraj, Sridevi

2017-12-01

Laboratory test in transport is a critical component of patient care, and capillary blood is a preferred sample type particularly in children. This study evaluated the performance of capillary blood testing on the epoc Point of Care Blood Analysis System (Alere Inc). Ten fresh venous blood samples was tested on the epoc system under the capillary mode. Correlation with GEM 4000 (Instrumentation Laboratory) was examined for Na+, K+, Cl-, Ca2+, glucose, lactate, hematocrit, hemoglobin, pO2, pCO2, and pH, and correlation with serum tested on Vitros 5600 (Ortho Clinical Diagnostics) was examined for creatinine. Eight paired capillary and venous blood was tested on epoc and ABL800 (Radiometer) for the correlation of Na+, K+, Cl-, Ca2+, glucose, lactate, hematocrit, hemoglobin, pCO2, and pH. Capillary blood from 23 apparently healthy volunteers was tested on the epoc system to assess the concordance to reference ranges used locally. Deming regression correlation coefficients for all the comparisons were above 0.65 except for ionized Ca2+. Accordance of greater than 85% to the local reference ranges were found in all assays with the exception of pO2 and Cl-. Data from this study indicates that capillary blood tests on the epoc system provide comparable results to reference method for these assays, Na+, K+, glucose, lactate, hematocrit, hemoglobin, pCO2, and pH. Further validation in critically ill patients is needed to implement the epoc system in patient transport. This study demonstrated that capillary blood tests on the epoc Point of Care Blood Analysis System give comparable results to other chemistry analyzers for major blood gas and critical tests. The results are informative to institutions where pre-hospital and inter-hospital laboratory testing on capillary blood is a critical component of patient point of care testing.

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

Science.gov (United States)

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.

X-ray focusing using capillary arrays

International Nuclear Information System (INIS)

Nugent, K.A.; Chapman, H.N.

1990-01-01

A new form of X-ray focusing device based on glass capillary arrays is presented. Theoretical and experimental results for array of circular capillaries and theoretical and computational results for square hole capillaries are given. It is envisaged that devices such as these will find wide applications in X-ray optics as achromatic condensers and collimators. 3 refs., 4 figs

Microfluidic chip-capillary electrophoresis devices

CERN Document Server

Fung, Ying Sing; Du, Fuying; Guo, Wenpeng; Ma, Tongmei; Nie, Zhou; Sun, Hui; Wu, Ruige; Zhao, Wenfeng

2015-01-01

Capillary electrophoresis (CE) and microfluidic chip (MC) devices are relatively mature technologies, but this book demonstrates how they can be integrated into a single, revolutionary device that can provide on-site analysis of samples when laboratory services are unavailable. By introducing the combination of CE and MC technology, Microfluidic Chip-Capillary Electrophoresis Devices broadens the scope of chemical analysis, particularly in the biomedical, food, and environmental sciences. The book gives an overview of the development of MC and CE technology as well as technology that now allows for the fabrication of MC-CE devices. It describes the operating principles that make integration possible and illustrates some achievements already made by the application of MC-CE devices in hospitals, clinics, food safety, and environmental research. The authors envision further applications for private and public use once the proof-of-concept stage has been passed and obstacles to increased commercialization are ad...

Micro-injector for capillary electrophoresis.

Science.gov (United States)

Sáiz, Jorge; Koenka, Israel Joel; García-Ruiz, Carmen; Müller, Beat; Chwalek, Thomas; Hauser, Peter C

2015-08-01

A novel micro-injector for capillary electrophoresis for the handling of samples with volumes down to as little as 300 nL was designed and built in our laboratory for analyses in which the available volume is a limitation. The sample is placed into a small cavity located directly in front of the separation capillary, and the injection is then carried out automatically by controlled pressurization of the chamber with compressed air. The system also allows automated flushing of the injection chamber as well as of the capillary. In a trial with a capillary electrophoresis system with contactless conductivity detector, employing a capillary of 25 μm diameter, the results showed good stability of migration times and peak areas. To illustrate the technique, the fast separation of five inorganic cations (Na(+) , K(+) , NH4 (+) , Ca(2+) , and Mg(2+) ) was set up. This could be achieved in less than 3 min, with good limits of detection (10 μM) and linear ranges (between about 10 and 1000 μM). The system was demonstrated for the determination of the inorganic cations in porewater samples of a lake sediment core. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The role of nailfold capillary dropout on mortality in systemic sclerosis.

Science.gov (United States)

Tieu, Joanna; Hakendorf, Paul; Woodman, Richard J; Patterson, Karen; Walker, Jenny; Roberts-Thomson, Peter

2018-05-01

Semi-quantitative wide-field nailfold capillaroscopy (NFC) is a simple technique with proven utility in the early diagnosis of systemic sclerosis (SSc). Its role in prognosis, however, remains uncertain. To investigate the possible utility of NFC in predicting survival. Patients with SSc listed on the South Australian Scleroderma Register (SASR) with prior NFC performed at Flinders Medical Centre from 1991 to 2015 were included in this study. Baseline demographic data, diagnosis, scleroderma antibody status and mortality status were also collected for each patient. The cohort consisted of 99 patients with limited cutaneous SSc, 30 patients with diffuse cutaneous SSc and 23 with an overlap scleroderma syndrome. Fifty-six patients died during the period of study (censured end June 2015). Patients with diffuse scleroderma had significantly greater capillary dropout compared with limited and overlap scleroderma (P dropout scores (log-rank χ 2 = 8.75, P = 0.003) and antibody status (log-rank χ 2 = 13.94, P = 0.003) were associated with mortality. ANOVA showed a significant association between antibody status and capillary dropout (P dropout attenuated the impact of autoantibody group on survival. Nailfold capillary dropout was significantly associated with mortality and the severity of dropout attenuates survival dictated by antibody status. Together these observations support the hypothesis that capillary dropout is on the causal pathway between induction of scleroderma associated autoantibodies and mortality. © 2018 Royal Australasian College of Physicians.

Design of Capillary Flows with Spatially Graded Porous Films

Science.gov (United States)

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.

Local CD34-positive capillaries decrease in mouse models of kidney disease associating with the severity of glomerular and tubulointerstitial lesions.

Science.gov (United States)

Masum, Md Abdul; Ichii, Osamu; Elewa, Yaser Hosny Ali; Nakamura, Teppei; Kon, Yasuhiro

2017-09-04

The renal vasculature plays important roles in both homeostasis and pathology. In this study, we examined pathological changes in the renal microvascular in mouse models of kidney diseases. Glomerular lesions (GLs) in autoimmune disease-prone male BXSB/MpJ-Yaa (Yaa) mice and tubulointerstitial lesions (TILs) in male C57BL/6 mice subjected to unilateral ureteral obstruction (UUO) for 7 days were studied. Collected kidneys were examined using histopathological techniques. A nonparametric Mann-Whitney U test (P < 0.05) was performed to compare healthy controls and the experimental mice. The Kruskal-Wallis test was used to compare three or more groups, and multiple comparisons were performed using Scheffe's method when significant differences were observed (P < 0.05). Yaa mice developed severe autoimmune glomerulonephritis, and the number of CD34 + glomerular capillaries decreased significantly in GLs compared to that in control mice. However, UUO-treated mice showed severe TILs only, and CD34 + tubulointerstitial capillaries were decreased significantly in TILs with the progression of tubulointerstitial fibrosis compared to those in untreated control kidneys. Infiltrations of B-cells, T-cells, and macrophages increased significantly in the respective lesions of both disease models (P < 0.05). In observations of vascular corrosion casts by scanning electron microscopy and of microfil rubber-perfused thick kidney sections by fluorescence microscopy, segmental absences of capillaries were observed in the GLs and TILs of Yaa and UUO-treated mice, respectively. Further, transmission electron microscopy revealed capillary endothelial injury in the respective lesions of both models. The numbers of CD34 + glomerular and tubulointerstitial capillaries were negatively correlated with all examined parameters in GLs (P < 0.05) and TILs (P < 0.01), respectively. From the analysis of mouse models, we identified inverse pathological correlations between the number of

Sheathless interface for coupling capillary electrophoresis with mass spectrometry

Science.gov (United States)

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.

A model for capillary rise in micro-tube restrained by a sticky layer

Science.gov (United States)

Shen, Anqi; Xu, Yun; Liu, Yikun; Cai, Bo; Liang, Shuang; Wang, Fengjiao

2018-06-01

Fluid transport in a microscopic capillary under the effects of a sticky layer was theoretically investigated. A model based on the classical Lucas-Washburn (LW) model is proposed for the meniscus rise with the sticky layer present. The sticky layer consists of two parts: a fixed (located at the wall) and a movable part (located on the inside of the capillary), affecting the micro-capillary flow in different ways. Within our model, the movable layer is defined by the capillary radius and pressure gradient. From the model it follows that the fixed sticky layer leads to a decrease of capillary radius, while the movable sticky layer increases flow resistance. The movable layer thickness varies with the pressure gradient, which in turn varies with the rising of the meniscus. The results of our theoretical calculation also prove that the capillary radius has a greater effect on the meniscus height, rather than the additional resistance caused by the movable layer. Moreover, the fixed sticky layer, which affects the capillary radius, has a greater influence than the movable sticky layer. We conclude that the sticky layer causes a lower imbibition height than the LW model predicts.

Evaporation Limited Radial Capillary Penetration in Porous Media.

Science.gov (United States)

Liu, Mingchao; Wu, Jian; Gan, Yixiang; Hanaor, Dorian A H; Chen, C Q

2016-09-27

The capillary penetration of fluids in thin porous layers is of fundamental interest in nature and various industrial applications. When capillary flows occur in porous media, the extent of penetration is known to increase with the square root of time following the Lucas-Washburn law. In practice, volatile liquid evaporates at the surface of porous media, which restricts penetration to a limited region. In this work, on the basis of Darcy's law and mass conservation, a general theoretical model is developed for the evaporation-limited radial capillary penetration in porous media. The presented model predicts that evaporation decreases the rate of fluid penetration and limits it to a critical radius. Furthermore, we construct a unified phase diagram that describes the limited penetration in an annular porous medium, in which the boundaries of outward and inward liquid are predicted quantitatively. It is expected that the proposed theoretical model will advance the understanding of penetration dynamics in porous media and facilitate the design of engineered porous architectures.

Enantioselective analysis of drugs: contributions of high-performance liquid chromatography and capillary electrophoresis

OpenAIRE

Bonato, Pierina Sueli; Jabor, Valquíria Aparecida Polisel; Gaitani, Cristiane Masetto de

2005-01-01

The demand for analytical methods suitable for accurate and reproducible determination of drug enantiomers has increased significantly in the last years. High-performance liquid chromatography (HPLC) using chiral stationary phases and capillary electrophoresis (CE) are the most important techniques used for this purpose. In this paper, the fundamental aspects of chiral separations using both techniques are presented. Some important aspects for the development of enantioselective methods, part...

Qualitative and quantitative assessment of nailfold capillaries by capillaroscopy in healthy volunteers.

Science.gov (United States)

Hoerth, Christian; Kundi, Michael; Katzenschlager, Reinhold; Hirschl, Mirko

2012-01-01

Nailfold capillaroscopy (NVC) is a diagnostic tool particularly useful in the differential diagnosis of rheumatic and connective tissue diseases. Although successfully applied since many years, little is known about prevalence and distribution of NVC changes in healthy individuals. NVC was performed in 120 individuals (57 men and 63 women; age 18 to 70 years) randomly selected according to predefined age and sex strata. Diseases associated with NVC changes were excluded. The nailfolds of eight fingers were assessed according to standardized procedures. A scoring system was developed based on the distribution of the number of morphologically deviating capillaries, microhaemorrhages, and capillary density. Only 18 individuals (15 %) had no deviation in morphology, haemorrhages, or capillary density on any finger. Overall 67 % had morphological changes, 48 % had microhaemorrhages, and 40 % of volunteers below 40 years of age and 18 % above age 40 had less than 8 capillaries/mm. Among morphological changes tortous (43 %), ramified (47 %), and bushy capillaries (27 %) were the most frequently altered capillary types. A semiquantitative scoring system was developed in such a way that a score above 1 indicates an extreme position (above the 90th percentile) in the distribution of scores among healthy individuals. Altered capillaries occur frequently among healthy individuals and should be interpreted as normal unless a suspicious increase in their frequency is determined by reference to the scoring system. Megacapillaries and diffuse loss of capillaries were not found and seem to be of specific diagnostic value.

Separation of oligopeptides, nucleobases, nucleosides and nucleotides using capillary electrophoresis/electrochromatography with sol-gel modified inner capillary wall.

Science.gov (United States)

Svobodová, Jana; Kofroňová, Olga; Benada, Oldřich; Král, Vladimír; Mikšík, Ivan

2017-09-29

The aim of this article is to study the modification of an inner capillary wall with sol-gel coating (pure silica sol-gel or silica sol-gel containing porphyrin-brucine conjugate) and determine its influence on the separation process using capillary electrophoresis/electrochromatography method. After modification of the inner capillary surface the separation of analytes was performed using two different phosphate buffers (pH 2.5 and 9.0) and finally the changes in electrophoretic mobilities of various samples were calculated. To confirm that the modification of the inner capillary surface was successful, the parts of the inner surfaces of capillaries were observed using scanning electron microscopy. The analytes used as testing samples were oligopeptides, nucleosides, nucleobases and finally nucleotides. Copyright © 2017 Elsevier B.V. All rights reserved.

Effects of anesthesia on the cerebral capillary blood flow in young and old mice

Science.gov (United States)

Moeini, Mohammad; Tabatabaei, Maryam S.; Bélanger, Samuel; Avti, Pramod; Castonguay, Alexandre; Pouliot, Philippe; Lesage, Frédéric

2015-03-01

Despite recent findings on the possible role of age-related cerebral microvasculature changes in cognition decline, previous studies of capillary blood flow in aging (using animal models) are scarce and limited to anesthetized conditions. Since anesthesia can have different effects in young and old animals, it may introduce a confounding effect in aging studies. The present study aimed to eliminate the potential confound introduced by anesthesia by measuring capillary blood flow parameters in both awake conditions and under isoflurane anesthesia. We used 2-photon laser scanning fluorescence microscopy to measure capillary diameter, red blood cell velocity and flux, hematocrit and capillary volumetric flow in individual capillaries in the barrel cortex of 6- and 24-month old C57Bl/6 mice. It was observed that microvascular properties are significantly affected by anesthesia leading to different trends in capillary blood flow parameters with aging when measured under awake or anesthetized conditions. The findings in this study suggest taking extra care in interpreting aging studies from anesthetized animals.

Reliability of widefield capillary microscopy to measure nailfold capillary density in systemic sclerosis.

Science.gov (United States)

Hudson, M; Masetto, A; Steele, R; Arthurs, E; Baron, M

2010-01-01

To determine intra- and inter-observer reliability of widefield microscopy to measure nailfold capillary density in patients with systemic sclerosis (SSc). Five SSc patients were examined with a STEMV-8 Zeiss biomicroscope with 50x magnification. The nailfold of the second, third, fourth and fifth fingers of both hands of each patient were photographed twice by each of two observers, once in the morning and again in the afternoon (total of 32 pictures). Two raters reviewed the photographs to produce capillary density readings. Intra- and inter-rater reliability of the readings were computed using intra-class correlations (ICC). Additional analyses were undertaken to determine the impact of other sources of variability in the data, namely patient, finger, technician and time. Intra-and inter-rater reliability were substantial (ICC 0.72-0.84) when raters were reading the same photographs or photographs taken at the same time of day. Agreement was only fair between morning and afternoon density readings (ICC 0.30-0.37). Patients, individual fingers and technician accounted for a large part of the variability in the data (combined variance component of 7.69 out of the total 12.23). The coefficient of variation of widefield microscopy was 24%. Although intra- and inter-rater reliability of nailfold capillary density measurements using widefield microscopy are good, proper standardisation of the conditions under which capillaroscopy is done and better imaging of nailfold capillary abnormalities should be considered if nailfold capillary density is to be used as an outcome measure in multi-centre clinical trials in SSc.

Analysis of Capillary Coating Die Flow in an Optical Fiber Coating Applicator

OpenAIRE

Kyoungjin Kim

2011-01-01

Viscous heating becomes significant in the high speed resin coating process of glass fibers for optical fiber manufacturing. This study focuses on the coating resin flows inside the capillary coating die of optical fiber coating applicator and they are numerically simulated to examine the effects of viscous heating and subsequent temperature increase in coating resin. Resin flows are driven by fast moving glass fiber and the pressurization at the coating die inlet, while ...

An improved interface for capillary zone electrophoresis-mass spectrometry

International Nuclear Information System (INIS)

Smith, R.D.; Loo, J.A.; Barinaga, C.J.; Udseth, H.R.

1988-06-01

We have recently developed an improved electrospray ionization interface for capillary electrophoresis mass-spectrometry (CZE-MS). Our initial interface employed a vacuum deposited metal film at the exit of the capillary to make an electrical contact with he eluting buffer and establish the electrospray field gradient. This interface did, however, impose significant limitations on the range of capillary electrophoretic (CE) separations that could be performed. To circumvent these limitations, an interface that does not require a metalized tip was designed nd developed. In the new approach, the electrical contact at the column exit is made through a flowing liquid sheath. The principal advantage of this interface is that it allows operation with a much broader range of electrophoresis conditions. The sheath flow can be readily varied in both composition and volume. An electrospray ionization spectrum is given for a previously intractable buffer solution. 5 refs., 2 figs

Exercise induced capillary growth in human skeletal muscle and the dynamics of VEGF

DEFF Research Database (Denmark)

Høier, Birgitte; Hellsten, Ylva

2014-01-01

, such as shear stress and passive stretch, lead to cellular signalling, enhanced expression of angiogenic factors and initiation of capillary growth. The most central angiogenic factor in skeletal muscle capillary growth is vascular endothelial growth factor (VEGF). During muscle contraction, VEGF increases...... in the muscle interstitium, acts on VEGF receptors on the capillary endothelium and thereby stimulates angiogenic processes. A primary source of muscle interstitial VEGF during exercise is the skeletal muscle fibers which contain large stores of VEGF within vesicles. We propose that, during muscle activity...

Evaluation and management of Periocular Capillary Hemangioma: A review

International Nuclear Information System (INIS)

Al-Motowa, Saeed A.; Chaudhry, Imtiaz A.

2006-01-01

To review the salient features of periocular capillary hemangioma, provide the ophthalmologist with clinical, diagnostic and histological features characteristic of the tumor and discuss various methods of management. Methods were literature review of periocular capillary hemangioma, diagnostic evaluation with emphasis on treatment through the presentation of illustrative clinical cases. Capillary hemangioma is the most common benign vascular tumor found on the head and neck area including eyelids and orbit. The lesion typically manifests within the first few weeks of life, grows rapidly in the first year during the proliferative phase, then invariably and slowly regresses over the next 4 to 5 years during the involutional phase. The lesion may resolve without leaving any significant cosmetic sequelae in vast majority of patients, however, the functional defects in the form of amblyopia, squint, facial disfigurement and rarely optic atrophy may persist long after complete resolution of the tumor. The diagnosis of the capillary hemangioma requires a combination of clinical and imaging studies such as ultrasonography, computerized tomography, magnetic resonance imaging and angiography in selected cases. With the advent of less invasive diagnostic techniques, the need for biopsy in capillary hemangioma has decreased. Nevertheless, it should be differentiated from other periocular tumors such as rhabdomyosarcoma, lymphangioma, chloroma, neuroblastoma, orbital cyst, and orbital cellulites. Treatment is indicated to prevent amblyopia or cosmetic disfigurement. If indicated, intra-lesional corticosteroids may be used to enhance resolution of the tumor. Other forms of treatment tried with variable success include systematic and topical corticosteroids, radiation, surgical excision and intravenous embolization of the tumor. Indecent years, laser ablation of the tumor has been found effective in some cases. Interferon-u has been utilized effectively in cases of capillary

Influence of random roughness on the adhesion between metal surfaces due to capillary condensation

OpenAIRE

van Zwol, P. J.; Palasantzas, G.; De Hosson, J. Th. M.

2007-01-01

The capillary force was measured by atomic force microscopy between a gold coated sphere mounted on a cantilever and gold surfaces with different roughnesses. For smooth surfaces the capillary adhesive force surpasses in magnitude any dispersion, e.g., van der Waals/Casimir and/or electrostatic forces. A substantial decrease in the capillary force was observed by increasing the roughness ampltitude a few nanometers in the range of 1-10 nm. From these measurements two limits can be defined: a ...

Static Response of Microbeams due to Capillary and Electrostatic Forces

KAUST Repository

Bataineh, Ahmad M.

2016-03-07

Micro-sensors or micro-switches usually operate under the effect of electrostatic force and could face some environmental effects like humidity, which may lead to condensation underneath the beams and create strong capillary forces. Those tiny structures are principally made of microbeams that can undergo instabilities under the effect of those created huge capillary forces. In fact, during the fabrication of microbeams, there is an important step to separate the beam from its substrate (wet etching). After this step, the microstructure is dried, which may causes the onset of some droplets of water trapped underneath the beam that could bring about a huge capillary force pulling it toward its substrate. If this force is bigger than the microbeam\\'s restoring force, it will become stuck to the substrate. This paper investigates the instability scenarios of both clamped-clamped (straight and curved) and cantilever (straight and curled) microbeams under the effect of capillary and/or electrostatic forces. The reduced order modeling (ROM) based on the Galerkin procedure is used to solve the nonlinear beam equations. The non-ideal boundaries are modeled by adding springs. The volume of the fluid between the beam and the substrate underneath it is varied and the relation between the volume of the water and the stability of the beam is shown. An analysis for the factors of which should be taken in to consideration in the fabrication processes to overcome the instability due to huge capillary forces is done. Also the size of the electrode for the electrostatic force is varied to show the effect on the micro-switch stability. A variation of the pull-in voltage with some specific beam parameters and with more than one case of electrode size is shown. It is found that capillary forces have a pronounced effect on the stability of microbeams. It is also found that the pull-in length decreases as the electrode size increases. It is also shown that the pull-in voltage decreases

Vesicle dynamics in shear and capillary flows

International Nuclear Information System (INIS)

Noguchi, Hiroshi; Gompper, Gerhard

2005-01-01

The deformation of vesicles in flow is studied by a mesoscopic simulation technique, which combines multi-particle collision dynamics for the solvent with a dynamically triangulated surface model for the membrane. Shape transitions are investigated both in simple shear flows and in cylindrical capillary flows. We focus on reduced volumes, where the discocyte shape of fluid vesicles is stable, and the prolate shape is metastable. In simple shear flow at low membrane viscosity, the shear induces a transformation from discocyte to prolate with increasing shear rate, while at high membrane viscosity, the shear induces a transformation from prolate to discocyte, or tumbling motion accompanied by oscillations between these two morphologies. In capillary flow, at small flow velocities the symmetry axis of the discocyte is found not to be oriented perpendicular to the cylinder axis. With increasing flow velocity, a transition to a prolate shape occurs for fluid vesicles, while vesicles with shear-elastic membranes (like red blood cells) transform into a coaxial parachute-like shape

Applications of capillary optics for focused ion beams

International Nuclear Information System (INIS)

Umezawa, Kenji

2014-01-01

This article introduces applications of focused ion beams (∼1 μm) with glass capillaries systems. A first report on the interaction between ion beams and glass capillaries was published in 1996. The guiding capabilities of glass capillaries were discovered due to ion reflection from inner wall of glass surfaces. Meanwhile, the similar optics have been already realized in focusing X-rays using glass capillaries. The basic technology of X-rays optics using glass capillaries had been developed in the 1980's and 1900's. Also, low energy atom scattering spectroscopy for insulator material analysis will be mentioned. (author)

Capillary versus Venous Hemoglobin Determination in the Assessment of Healthy Blood Donors

Science.gov (United States)

Patel, Abhilasha J.; Wesley, Robert; Leitman, Susan F.; Bryant, Barbara J.

2013-01-01

Background and Objectives To determine the accuracy of fingerstick hemoglobin assessment in blood donors, the performance of a portable hemoglobinometer (HemoCue Hb 201+) was prospectively compared with that of an automated hematology analyzer (Cell-Dyn 4000). Hemoglobin values obtained by the latter were used as the “true” result. Material and Methods Capillary fingerstick samples were assayed by HemoCue in 150 donors. Fingerstick samples from two sites, one on each hand, were obtained from a subset of 50 subjects. Concurrent venous samples were tested using both HemoCue and Cell-Dyn devices. Results Capillary hemoglobin values (HemoCue) were significantly greater than venous hemoglobin values (HemoCue), which in turn were significantly greater than venous hemoglobin values by Cell-Dyn (mean ± SD: 14.05 ± 1.51, 13.89 ± 1.31, 13.62 ± 1.23, respectively; phemoglobin screening criteria (≥12.5 g/dL) by capillary HemoCue, but were deferred by Cell-Dyn values (false-pass). Five donors (3%) were deferred by capillary sampling, but passed by Cell-Dyn (false-fail). Substantial variability in repeated fingerstick HemoCue results was seen (mean hemoglobin 13.72 vs. 13.70 g/dL, absolute mean difference between paired samples 0.76 g/dL). Hand dominance was not a factor. Conclusions Capillary samples assessed via a portable device yielded higher hemoglobin values than venous samples assessed on an automated analyzer. False-pass and false-fail rates were low and acceptable in the donor screening setting, with “true” values not differing by a clinically significant degree from threshold values used to assess acceptability for blood donation. PMID:23294266

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

Science.gov (United States)

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.

Mechanism of Kinetically Controlled Capillary Condensation in Nanopores: A Combined Experimental and Monte Carlo Approach.

Science.gov (United States)

Hiratsuka, Tatsumasa; Tanaka, Hideki; Miyahara, Minoru T

2017-01-24

We find the rule of capillary condensation from the metastable state in nanoscale pores based on the transition state theory. The conventional thermodynamic theories cannot achieve it because the metastable capillary condensation inherently includes an activated process. We thus compute argon adsorption isotherms on cylindrical pore models and atomistic silica pore models mimicking the MCM-41 materials by the grand canonical Monte Carlo and the gauge cell Monte Carlo methods and evaluate the rate constant for the capillary condensation by the transition state theory. The results reveal that the rate drastically increases with a small increase in the chemical potential of the system, and the metastable capillary condensation occurs for any mesopores when the rate constant reaches a universal critical value. Furthermore, a careful comparison between experimental adsorption isotherms and the simulated ones on the atomistic silica pore models reveals that the rate constant of the real system also has a universal value. With this finding, we can successfully estimate the experimental capillary condensation pressure over a wide range of temperatures and pore sizes by simply applying the critical rate constant.

Microgravity Investigation of Capillary Driven Imbibition

Science.gov (United States)

Dushin, V. R.; Nikitin, V. F.; Smirnov, N. N.; Skryleva, E. I.; Tyurenkova, V. V.

2018-05-01

The goal of the present paper is to investigate the capillary driven filtration in porous media under microgravity conditions. New mathematical model that allows taking into account the blurring of the front due to the instability of the displacement that is developing at the front is proposed. The constants in the mathematical model were selected on the basis of the experimental data on imbibition into unsaturated porous media under microgravity conditions. The flow under the action of a combination of capillary forces and a constant pressure drop or a constant flux is considered. The effect of capillary forces and the type of wettability of the medium on the displacement process is studied. A criterion in which case the capillary effects are insignificant and can be neglected is established.

Capillary detectors for high resolution tracking

CERN Document Server

Annis, P

1997-01-01

We present a new tracking device based on glass capillary bundles or layers filled with highly purified liquid scintillator and read out at one end by means of image intensifiers and CCD devices. A large-volume prototype consisting of 5 × 105 capillaries with a diameter of 20 μm and a length of 180 cm and read out by a megapixel CCD has been tested with muon and neutrino beams at CERN. With this prototype a two track resolution of 33 μm was achieved with passing through muons. Images of neutrino interactions in a capillary bundle have also been acquired and analysed. Read-out chains based on Electron Bombarded CCD (EBCCD) and image pipeline devices are also investigated. Preliminary results obtained with a capillary bundle read out by an EBCCD are presented.

Effects of intermediate wettability on entry capillary pressure in angular pores.

Science.gov (United States)

Rabbani, Harris Sajjad; Joekar-Niasar, Vahid; Shokri, Nima

2016-07-01

Entry capillary pressure is one of the most important factors controlling drainage and remobilization of the capillary-trapped phases as it is the limiting factor against the two-phase displacement. It is known that the entry capillary pressure is rate dependent such that the inertia forces would enhance entry of the non-wetting phase into the pores. More importantly the entry capillary pressure is wettability dependent. However, while the movement of a meniscus into a strongly water-wet pore is well-defined, the invasion of a meniscus into a weak or intermediate water-wet pore especially in the case of angular pores is ambiguous. In this study using OpenFOAM software, high-resolution direct two-phase flow simulations of movement of a meniscus in a single capillary channel are performed. Interface dynamics in angular pores under drainage conditions have been simulated under constant flow rate boundary condition at different wettability conditions. Our results shows that the relation between the half corner angle of pores and contact angle controls the temporal evolution of capillary pressure during the invasion of a pore. By deviating from pure water-wet conditions, a dip in the temporal evolution of capillary pressure can be observed which will be pronounced in irregular angular cross sections. That enhances the pore invasion with a smaller differential pressure. The interplay between the contact angle and pore geometry can have significant implications for enhanced remobilization of ganglia in intermediate contact angles in real porous media morphologies, where pores are very heterogeneous with small shape factors. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Genetic variability of Artemisia capillaris (Wormwood capillary) by ...

African Journals Online (AJOL)

The genetic variability among individuals of Artemisia capillaris from state of Terengganu, Malaysia was examined by using the random amplified polymorphic DNA (RAPD) technique. The samples were collected from differences regional in Terengganu State. The genomic DNA was extracted from the samples leaves.

Geometry-induced phase transition in fluids: capillary prewetting.

Science.gov (United States)

Yatsyshin, Petr; Savva, Nikos; Kalliadasis, Serafim

2013-02-01

We report a new first-order phase transition preceding capillary condensation and corresponding to the discontinuous formation of a curved liquid meniscus. Using a mean-field microscopic approach based on the density functional theory we compute the complete phase diagram of a prototypical two-dimensional system exhibiting capillary condensation, namely that of a fluid with long-ranged dispersion intermolecular forces which is spatially confined by a substrate forming a semi-infinite rectangular pore exerting long-ranged dispersion forces on the fluid. In the T-μ plane the phase line of the new transition is tangential to the capillary condensation line at the capillary wetting temperature T(cw). The surface phase behavior of the system maps to planar wetting with the phase line of the new transition, termed capillary prewetting, mapping to the planar prewetting line. If capillary condensation is approached isothermally with T>T(cw), the meniscus forms at the capping wall and unbinds continuously, making capillary condensation a second-order phenomenon. We compute the corresponding critical exponent for the divergence of adsorption.

On Capillary Rise and Nucleation

Science.gov (United States)

Prasad, R.

2008-01-01

A comparison of capillary rise and nucleation is presented. It is shown that both phenomena result from a balance between two competing energy factors: a volume energy and a surface energy. Such a comparison may help to introduce nucleation with a topic familiar to the students, capillary rise. (Contains 1 table and 3 figures.)

Fast separation of enantiomers by capillary electrophoresis using a combination of two capillaries with different internal diameters.

Science.gov (United States)

Šebestová, Andrea; Petr, Jan

2017-12-01

The combination of capillaries with different internal diameters was used to accelerate the separation of enantiomers in capillary electrophoresis. Separation of R,S-1,1'-binaphthalene-2,2'-diyl hydrogen phosphate using isopropyl derivative of cyclofructan 6 was studied as a model system. The best separation conditions included 500 mM sodium borate pH 9.5 with 60 mM concentration of the chiral selector. Separation lasted approx. 1.5 min using the combination of 50 and 100 μm id capillaries of 9.7 cm and 22.9 cm, respectively. It allowed approx. 12-fold acceleration in comparison to the traditional long-end separation mainly due to the higher electroosmotic flow generated in the connected capillaries. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Simulation of capillary bridges between nanoscale particles.

Science.gov (United States)

Dörmann, Michael; Schmid, Hans-Joachim

2014-02-04

Capillary forces are very important as they exceed in general other adhesion forces. But at the same time the exact calculation of these forces is very complex, so often assumptions and approximations are used. Previous research was done with regard to micrometer sized particles, but the behavior of nanoscale particles is different. Hence, the results for micrometer sized particles cannot be directly transferred when considering nanoscale particles. Therefore, a simulation method was developed to calculate numerically the shape of a rotationally symmetrical capillary bridge between two spherical particles or a particle and a plate. The capillary bridge in the gap between the particles is formed due to capillary condensation and is in thermodynamic equilibrium with the gas phase. Hence the Kelvin equation and the Young-Laplace equation can be used to calculate the profile of the capillary bridge, depending on the relative humidity of the surrounding air. The bridge profile consists of several elements that are determined consecutively and interpolated linearly. After the shape is determined, the volume and force, divided into capillary pressure force and surface tension force, can be calculated. The validation of this numerical model will be shown by comparison with several different analytical calculations for micrometer-sized particles. Furthermore, it is demonstrated that two often used approximations, (1) the toroidal approximation and (2) the use of an effective radius, cannot be used for nanoscale particles without remarkable mistake. It will be discussed how the capillary force and its components depend on different parameters, like particle size, relative humidity, contact angle, and distance, respectively. The rupture of a capillary bridge due to particle separation will also be presented.

Direct Numerical Simulation of Low Capillary Number Pore Scale Flows

Science.gov (United States)

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

Analysis of glycated hemoglobin A1c by capillary electrophoresis and capillary isoelectric focusing

Czech Academy of Sciences Publication Activity Database

Koval, Dušan; Kašička, Václav; Cottet, H.

2011-01-01

Roč. 413, č. 1 (2011), s. 8-15 ISSN 0003-2697 R&D Projects: GA ČR GP203/09/P485; GA ČR(CZ) GA203/08/1428 Institutional research plan: CEZ:AV0Z40550506 Keywords : capillary zone electrophoresis * capillary isoelectric focusing * glycated hemoglobin HbA1c Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 2.996, year: 2011

Numerical analysis of capillary compensated micropolar fluid lubricated hole-entry journal bearings

Directory of Open Access Journals (Sweden)

Nathi Ram

2016-06-01

Full Text Available The micropolar lubricated symmetric/asymmetric hole-entry bearings using capillary restrictor have been analyzed in the present work. Reynolds equation for micropolar lubricant has been derived and solved by FEM. The results have been computed using selected parameters of micropolar lubricant for hole-entry hydrostatic/hybrid journal bearings. A significant increase in damping and stiffness coefficients is observed for bearings having micropolar parameter N2=0.9, lm=10 than similar bearings under Newtonian lubricant. The threshold speed gets increased when symmetric bearing lubricated under micropolar fluid than Newtonian lubricant. The threshold speed gets increased when symmetric bearing lubricated under micropolar fluid than Newtonian lubricant.

Capillary detectors for high resolution tracking

International Nuclear Information System (INIS)

Annis, P.; Bay, A.; Bonekaemper, D.; Buontempo, S.; Ereditato, A.; Fabre, J.P.; Fiorillo, G.; Frekers, D.; Frenkel, A.; Galeazzi, F.; Garufi, F.; Goldberg, J.; Golovkin, S.; Hoepfner, K.; Konijn, J.; Kozarenko, E.; Kreslo, I.; Liberti, B.; Martellotti, G.; Medvedkov, A.; Mommaert, C.; Panman, J.; Penso, G.; Petukhov, Yu.; Rondeshagen, D.; Tyukov, V.; Vasilchenko, V.; Vilain, P.; Vischers, J.L.; Wilquet, G.; Winter, K.; Wolff, T.; Wong, H.

1997-01-01

We present a new tracking device based on glass capillary bundles or layers filled with highly purified liquid scintillator and read out at one end by means of image intensifiers and CCD devices. A large-volume prototype consisting of 5 x 10 5 capillaries with a diameter of 20 μm and a length of 180 cm and read out by a megapixel CCD has been tested with muon and neutrino beams at CERN. With this prototype a two track resolution of 33 μm was achieved with passing through muons. Images of neutrino interactions in a capillary bundle have also been acquired and analysed. Read-out chains based on electron bombarded CCD (EBCCD) and image pipeline devices are also investigated. Preliminary results obtained with a capillary bundle read out by an EBCCD are presented. (orig.)

Open tubular capillary column for the separation of cytochrome C tryptic digest in capillary electrochromatography.

Science.gov (United States)

Ali, Faiz; Cheong, Won Jo

2015-10-01

A silica capillary of 50 μm internal diameter and 500 mm length (416 mm effective length) was chemically modified with 4-(trifluoromethoxy) phenyl isocyanate in the presence of dibutyl tin dichloride as catalyst. Sodium diethyl dithiocarbamate was reacted with the terminal halogen of the bound ligand to incorporate the initiator moiety, and in situ polymerization was performed using a monomer mixture of styrene, N-phenylacrylamide, and methacrylic acid. The resultant open tubular capillary column immobilized with the copolymer layer was used for the separation of tryptic digest of cytochrome C in capillary electrochromatography. The sample was well eluted and separated into many components. The elution patterns of tryptic digest of cytochrome C were studied with respect to pH and water content in the mobile phase. This preliminary study demonstrates that open tubular capillary electrochromatography columns with a modified copolymer layer composed of proper nonpolar and polar units fabricated by reversible addition-fragmentation transfer polymerization can be useful as separation media for proteomic analysis. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Impaired increase of retinal capillary blood flow to flicker light exposure in arterial hypertension.

Science.gov (United States)

Ritt, Martin; Harazny, Joanna M; Ott, Christian; Raff, Ulrike; Bauernschubert, Philipp; Lehmann, Marina; Michelson, Georg; Schmieder, Roland E

2012-09-01

We hypothesized that the increase of retinal capillary blood flow (RCF) to flicker light exposure is impaired in subjects with arterial hypertension. In 146 nondiabetic untreated male subjects with (n=50) or without (n=96) arterial hypertension, RCF was measured before and after flicker light exposure noninvasively and in vivo using scanning laser Doppler flowmetry. In addition, in a subgroup of 28 subjects, the change of RCF to flicker light exposure was again assessed during parallel infusion of nitric oxide synthase inhibitor N-monomethyl-L-arginine (L-NMMA). The increase of RCF to flicker light exposure was lower in patients with untreated hypertension compared with normotensive subjects when expressed in absolute terms (7.69±54 versus 27.2±44 AU; P adjusted=0.013) or percent changes (2.95±14 versus 8.33±12%; P adjusted=0.023). Systolic (β=-0.216; P=0.023) but not diastolic blood pressure (β=-0.117; P=0.243) or mean arterial pressure (β=-0.178; P=0.073) was negatively related to the percent change of RCF to flicker light exposure, independently of other cardiovascular risk factors. In the subgroup of 28 subjects, the increase of RCF to flicker light exposure was similar at baseline and during parallel infusion of L-NMMA when expressed in absolute terms (20.0±51 versus 22.6±56 AU; P=0.731) or percent changes (7.12±16 versus 8.29±18%; P=0.607). The increase of RCF to flicker light exposure is impaired in arterial hypertension. In the subgroup of the total study cohort, nitric oxide was not a major determinant of the increase of RCF to flicker light exposure.

Numerical Simulation of Particle Distribution in Capillary Membrane during Backwash

Directory of Open Access Journals (Sweden)

Anik Keller

2013-09-01

Full Text Available The membrane filtration with inside-out dead-end driven UF-/MF- capillary membranes is an effective process for particle removal in water treatment. Its industrial application increased in the last decade exponentially. To date, the research activities in this field were aimed first of all at the analysis of filtration phenomena disregarding the influence of backwash on the operation parameters of filtration plants. However, following the main hypothesis of this paper, backwash has great potential to increase the efficiency of filtration. In this paper, a numerical approach for a detailed study of fluid dynamic processes in capillary membranes during backwash is presented. The effect of particle size and inlet flux on the backwash process are investigated. The evaluation of these data concentrates on the analysis of particle behavior in the cross sectional plane and the appearance of eventually formed particle plugs inside the membrane capillary. Simulations are conducted in dead-end filtration mode and with two configurations. The first configuration includes a particle concentration of 10% homogeneously distributed within the capillary and the second configuration demonstrates a cake layer on the membrane surface with a packing density of 0:6. Analyzing the hydrodynamic forces acting on the particles shows that the lift force plays the main role in defining the particle enrichment areas. The operation parameters contribute in enhancing the lift force and the heterogeneity to anticipate the clogging of the membrane.

Gel versus capillary electrophoresis genotyping for categorizing treatment outcomes in two anti-malarial trials in Uganda

Directory of Open Access Journals (Sweden)

Hubbard Alan E

2010-01-01

Full Text Available Abstract Background Molecular genotyping is performed in anti-malarial trials to determine whether recurrent parasitaemia after therapy represents a recrudescence (treatment failure or new infection. The use of capillary instead of agarose gel electrophoresis for genotyping offers technical advantages, but it is unclear whether capillary electrophoresis will result in improved classification of anti-malarial treatment outcomes. Methods Samples were genotyped using both gel and capillary electrophoresis from randomized trials of artemether-lumefantrine (AL vs. dihydroartemisinin-piperaquine (DP performed in two areas of Uganda: Kanungu, where transmission is moderate, and Apac, where transmission is very high. Both gel and capillary methods evaluated polymorphic regions of the merozoite surface protein 1 and 2 and glutamine rich protein genes. Results Capillary electrophoresis detected more alleles and provided higher discriminatory power than agarose gel electrophoresis at both study sites. There was only moderate agreement between classification of outcomes with the two methods in Kanungu (kappa = 0.66 and poor agreement in Apac (kappa = 0.24. Overall efficacy results were similar when using gel vs. capillary methods in Kanungu (42-day risk of treatment failure for AL: 6.9% vs. 5.5%, p = 0.4; DP 2.4% vs. 2.9%, p = 0.5. However, the measured risk of recrudescence was significantly higher when using gel vs. capillary electrophoresis in Apac (risk of treatment failure for AL: 17.0% vs. 10.7%, p = 0.02; DP: 8.5% vs. 3.4%, p = 0.03. Risk differences between AL and DP were not significantly different whether gel or capillary methods were used. Conclusions Genotyping with gel electrophoresis overestimates the risk of recrudescence in anti-malarial trials performed in areas of high transmission intensity. Capillary electrophoresis provides more accurate outcomes for such trials and should be performed when possible. In areas of moderate transmission

Gel versus capillary electrophoresis genotyping for categorizing treatment outcomes in two anti-malarial trials in Uganda.

Science.gov (United States)

Gupta, Vinay; Dorsey, Grant; Hubbard, Alan E; Rosenthal, Philip J; Greenhouse, Bryan

2010-01-15

Molecular genotyping is performed in anti-malarial trials to determine whether recurrent parasitaemia after therapy represents a recrudescence (treatment failure) or new infection. The use of capillary instead of agarose gel electrophoresis for genotyping offers technical advantages, but it is unclear whether capillary electrophoresis will result in improved classification of anti-malarial treatment outcomes. Samples were genotyped using both gel and capillary electrophoresis from randomized trials of artemether-lumefantrine (AL) vs. dihydroartemisinin-piperaquine (DP) performed in two areas of Uganda: Kanungu, where transmission is moderate, and Apac, where transmission is very high. Both gel and capillary methods evaluated polymorphic regions of the merozoite surface protein 1 and 2 and glutamine rich protein genes. Capillary electrophoresis detected more alleles and provided higher discriminatory power than agarose gel electrophoresis at both study sites. There was only moderate agreement between classification of outcomes with the two methods in Kanungu (kappa = 0.66) and poor agreement in Apac (kappa = 0.24). Overall efficacy results were similar when using gel vs. capillary methods in Kanungu (42-day risk of treatment failure for AL: 6.9% vs. 5.5%, p = 0.4; DP 2.4% vs. 2.9%, p = 0.5). However, the measured risk of recrudescence was significantly higher when using gel vs. capillary electrophoresis in Apac (risk of treatment failure for AL: 17.0% vs. 10.7%, p = 0.02; DP: 8.5% vs. 3.4%, p = 0.03). Risk differences between AL and DP were not significantly different whether gel or capillary methods were used. Genotyping with gel electrophoresis overestimates the risk of recrudescence in anti-malarial trials performed in areas of high transmission intensity. Capillary electrophoresis provides more accurate outcomes for such trials and should be performed when possible. In areas of moderate transmission, gel electrophoresis appears adequate to estimate comparative

Relationship between changed alveolar-capillary permeability and angiotensin converting enzyme activity in serum in sarcoidosis.

OpenAIRE

Eklund, A; Blaschke, E

1986-01-01

The effect of altered alveolar-capillary permeability on angiotensin converting enzyme (ACE) activity in serum (SACE) was studied in 45 patients with sarcoidosis and 21 healthy controls. In sarcoidosis increased albumin concentrations in the bronchoalveolar lavage fluid (L albumin) and increased ratios of L albumin to albumin in serum (S albumin) indicated an increased permeability of the alveolar-capillary membrane. ACE activity in the lavage fluid (LACE) was correlated with the number of al...

[Effect of microneedle combined with Lauromacrogol on skin capillary network: experimental study].

Science.gov (United States)

Xu, Sida; Wei, Qiang; Fan, Youfen; Chen, Shihai; Liu, Qingfeng; Yin, Guoqiang; Liao, Mingde; Sun, Yu

2014-11-01

To explore the effect of microneedle combined with Lauromacrogol on skin capillary network. 24 male Leghone (1.5-2.0 kg in weight) were randomly divided into three groups as group A (microneedle combined with Lauromacrogol), B (microneedle combined with physiological saline) , and C(control). The cockscombs were treated. The specimens were taken on the 7th, 14th, 21th , and 28th day postoperatively. HE staining, immunohistochemical staining and special staining were performed for study of the number of capillary and collagen I/III , as well as elastic fibers. The color of cockscombs in group A became lightening after treatment. The number of capillary decreased as showing by HE staining. The collagen I and III in group B was significantly different from that in group A and C (P microneedle combined with Lauromacrogol could effectively reduce the capillary in cockscomb without any tissue fibrosis. Microneedle can stimulate the proliferation of elastic fiber, so as to improve the skin ageing process.

Assembly for connecting the column ends of two capillary columns

International Nuclear Information System (INIS)

Kolb, B.; Auer, M.; Pospisil, P.

1984-01-01

In gas chromatography, the column ends of two capillary columns are inserted into a straight capillary from both sides forming annular gaps. The capillary is located in a tee out of which the capillary columns are sealingly guided, and to which carrier gas is supplied by means of a flushing flow conduit. A ''straight-forward operation'' having capillary columns connected in series and a ''flush-back operation'' are possible. The dead volume between the capillary columns can be kept small

Biomimetic Unidirectional Capillary Action

Science.gov (United States)

Rupert, Eric; Moran, Patrick; Dahl, Jason

2017-11-01

In arid environments animals require specialized adaptations to collect adequate water. The Texas horned lizard (P. cornutum) has superhydrophylic skin which draws water out of moist soil or directly from water sources. The water then makes its way into the lizard's unidirectional capillary system, made of overlapping scales, which serves to channel water to its mouth. Testing different channel geometries, repeated ``D'' shaped chambers as in Commans et al. (2015) and truncated isosceles triangle chambers, as found in P. cornutum, we show the ability to have passive, unidirectional, fluid transport. Tests were carried out with the capillaries in a horizontal configuration. While both capillary geometries produced the desired traits, the triangular chambers showed superior unidirectionality, with no observed back flow, while ``D'' chambers showed back flow under testing conditions. The chambers provided similar flow rates. These types of channel systems will find use in microfluidics, notably in medical, printing, and lab-on-chip applications.

Effect of hindpaw electrical stimulation on capillary flow heterogeneity and oxygen delivery (Conference Presentation)

Science.gov (United States)

Li, Yuandong; Wei, Wei; Li, Chenxi; Wang, Ruikang K.

2017-02-01

We report a novel use of optical coherence tomography (OCT) based angiography to visualize and quantify dynamic response of cerebral capillary flow pattern in mice upon hindpaw electrical stimulation through the measurement of the capillary transit-time heterogeneity (CTH) and capillary mean transit time (MTT) in a wide dynamic range of a great number of vessels in vivo. The OCT system was developed to have a central wavelength of 1310 nm, a spatial resolution of 8 µm and a system dynamic range of 105 dB at an imaging rate of 92 kHz. The mapping of dynamic cerebral microcirculations was enabled by optical microangiography protocol. From the imaging results, the spatial homogenization of capillary velocity (decreased CTH) was observed in the region of interest (ROI) corresponding to the stimulation, along with an increase in the MTT in the ROI to maintain sufficient oxygen exchange within the brain tissue during functional activation. We validated the oxygen consumption due to an increase of the MTT through demonstrating an increase in the deoxygenated hemoglobin (HbR) during the stimulation by the use of laser speckle contrast imaging.

Rapid capillary coating by epoxy-poly-(dimethylacrylamide): Performance in capillary zone electrophoresis of protein and polystyrene carboxylate

Czech Academy of Sciences Publication Activity Database

Chiari, M.; Cretich, M.; Šťastná, Miroslava; Radko, S. P.; Chrambach, A.

2001-01-01

Roč. 22, č. 4 (2001), s. 656-659 ISSN 0173-0835 Institutional research plan: CEZ:AV0Z4031919 Keywords : capillary coating * capillary zone electrophoresis * proteins Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 4.282, year: 2001

The penetration of aerosols through fine capillaries

International Nuclear Information System (INIS)

Mitchell, J.P.; Edwards, R.T.; Ball, M.H.E.

1989-10-01

A novel experimental technique has been developed to study the penetration of aerosol particles ranging from about 1 to 15 μm aerodynamic diameter through capillaries varying from 20 to 80 μm bore and from 10 to 50 mm in length. When the driving pressure was 100 kPa, the penetration of the airborne particles was considerably smaller than expected from a simple comparison of particle diameter with the bore of the capillary. Particle size distributions determined after penetration through the capillaries were in almost all cases similar to the particle size distribution of the aerosol at the capillary entrance. This lack of size-selectivity can be explained in terms of the capillary behaving as a conventional suction-based sampler from a near still (calm) air environment. The resulting particle penetration data are important in assessing the potential for the leakage of aerosols through seals in containers used to transport radioactive materials. (author)

Intracranial capillary hemangioma mimicking a dissociative disorder

Directory of Open Access Journals (Sweden)

Alexander Lacasse

2012-01-01

Full Text Available Capillary hemangiomas, hamartomatous proliferation of vascular endothelial cells, are rare in the central nervous system (CNS. Intracranial capillary hemangiomas presenting with reversible behavioral abnormalities and focal neurological deficits have rarely been reported. We report a case of CNS capillary hemangioma presenting with transient focal neurological deficits and behavioral abnormalities mimicking Ganser’s syndrome. Patient underwent total excision of the vascular malformation, resulting in complete resolution of his symptoms.

Capillary condensation between disks in two dimensions

OpenAIRE

Gil, Tamir; Ipsen, John Hjorth

1997-01-01

Capillary condensation between two two-dimensional wetted circular substrates (disks) is studied by an effective free energy description of the wetting interface. The interfacial free-energy potential is developed on the basis of the theory for the wetting of a single disk, where interfacial capillary fluctuations play a dominant role. A simple approximative analytical expression of the interfacial free energy is developed and is validated numerically. The capillary condensation is characteri...

A novel imaging technique to measure capillary-refill time: improving diagnostic accuracy for dehydration in young children with gastroenteritis.

Science.gov (United States)

Shavit, Itai; Brant, Rollin; Nijssen-Jordan, Cheri; Galbraith, Roger; Johnson, David W

2006-12-01

Assessment of dehydration in young children currently depends on clinical judgment, which is relatively inaccurate. By using digital videography, we developed a way to assess capillary-refill time more objectively. Our goal was to determine whether digitally measured capillary-refill time assesses the presence of significant dehydration (> or = 5%) in young children with gastroenteritis more accurately than conventional capillary refill and overall clinical assessment. We prospectively enrolled children with gastroenteritis, 1 month to 5 years of age, who were evaluated in a tertiary-care pediatric emergency department and judged by a triage nurse to be at least mildly dehydrated. Before any treatment, we measured the weight and digitally measured capillary-refill time of these children. Pediatric emergency physicians determined capillary-refill time by using conventional methods and degree of dehydration by overall clinical assessment by using a 7-point Likert scale. Postillness weight gain was used to estimate fluid deficit; beginning 48 hours after assessment, children were reweighed every 24 hours until 2 sequential weights differed by no more than 2%. We compared the accuracy of digitally measured capillary-refill time with conventional capillary refill and overall clinical assessment by determining sensitivities, specificities, likelihood ratios, and area under the receiver operator characteristic curves. A total of 83 patients were enrolled and had complete follow-up; 13 of these patients had significant dehydration (> or = 5% of body weight). The area under the receiver operator characteristic curves for digitally measured capillary-refill time and overall clinical assessment relative to fluid deficit ( or = 5%) were 0.99 and 0.88, respectively. Positive likelihood ratios were 11.7 for digitally measured capillary-refill time, 4.5 for conventional capillary refill, and 4.1 for overall clinical assessment. Results of this prospective cohort study suggest

A star-shaped poly(2-methyl-2-oxazoline)-based antifouling coating: Application in investigation of the interaction between acetaminophen and bovine serum albumin by frontal analysis capillary electrophoresis.

Science.gov (United States)

Du, Haiqin; Zhang, Chong; Mao, Ke; Wang, Yanmei

2017-08-01

In this work, an antifouling capillary modified with star-shaped poly(2-methyl-2-oxazoline)-based copolymer was used to study the interaction between acetaminophen (APAP) and bovine serum albumin (BSA) by frontal analysis capillary electrophoresis (FACE). The star-shaped copolymer, poly(ethylene imine)-graft-poly(2-methyl-2-oxazoline) (PEI-g-PMOXA), was immobilized onto the fused-silica capillary inner wall via dopamine-assisted co-deposition strategy, yielding a PEI-g-PMOXA/polydopamine (PDA)-coated antifouling capillary, i.e., an antifouling capillary coated with the PEI-g-PMOXA/PDA co-deposited film. Electroosmotic flow (EOF) mobility of the PEI-g-PMOXA/PDA-coated capillary was almost zero in a wide pH range (3.0-10.0), while the EOF mobility of bare capillary was much larger and increased significantly with pH increasing. When the PEI-g-PMOXA/PDA-coated capillary was exploited to separate a protein mixture including cytochrome c, lysozyme, ribonuclease A and α-chymotrypsinogen A, the theoretical plate numbers were of five orders of magnitude which were about ten-fold higher over those obtained with bare capillary; in addition, the RSD values of migration time were mostly less than 0.7% (30 consecutive runs) which were much smaller than those of bare capillary (c.a. 5.7%). The protein-resistant PEI-g-PMOXA/PDA-coated capillary was then used to investigate the interaction between APAP and BSA by FACE, the binding constant and number of binding sites at 25°C and pH 7.4 (Tris/HCl buffer of 25mM) were 1.39×10 4 M -1 and 1.08, respectively, which were comparable to the results determined by fluorescence spectroscopic measurement (3.18×10 4 M -1 and 1.19, respectively). Copyright © 2017 Elsevier B.V. All rights reserved.

Surfactant Protein D Levels in Umbilical Cord Blood and Capillary Blood of Premature Infants

DEFF Research Database (Denmark)

Dahl, Marianne; Holmskov, Uffe; Husby, Steffen

2006-01-01

of SP-D in capillary blood day 1 was 1,466 ng/mL (range 410-5,051 ng/mL), with lowest values in infants born with ROM and delivered vaginally. High SP-D levels in umbilical cord blood and capillary blood on day 1 were found to be more likely in infants in need for respiratory support or surfactant...... treatment and susceptibility to infections. We conclude that SP-D concentrations in umbilical cord blood and capillary blood in premature infants are twice as high as in mature infants and depend on several perinatal conditions. High SP-D levels in umbilical cord blood and capillary blood on day 1 were...... found to be related to increased risk of RDS and infections....

Genetics Home Reference: megalencephaly-capillary malformation syndrome

Science.gov (United States)

... Additional NIH Resources (1 link) National Institute of Neurological Disorders and Stroke: Megalencephaly Educational Resources (5 links) Boston Children's Hospital: Capillary Malformation Cincinnati Children's Hospital: Capillary Malformations ...

Cell adhesion during bullet motion in capillaries.

Science.gov (United States)

Takeishi, Naoki; Imai, Yohsuke; Ishida, Shunichi; Omori, Toshihiro; Kamm, Roger D; Ishikawa, Takuji

2016-08-01

A numerical analysis is presented of cell adhesion in capillaries whose diameter is comparable to or smaller than that of the cell. In contrast to a large number of previous efforts on leukocyte and tumor cell rolling, much is still unknown about cell motion in capillaries. The solid and fluid mechanics of a cell in flow was coupled with a slip bond model of ligand-receptor interactions. When the size of a capillary was reduced, the cell always transitioned to "bullet-like" motion, with a consequent decrease in the velocity of the cell. A state diagram was obtained for various values of capillary diameter and receptor density. We found that bullet motion enables firm adhesion of a cell to the capillary wall even for a weak ligand-receptor binding. We also quantified effects of various parameters, including the dissociation rate constant, the spring constant, and the reactive compliance on the characteristics of cell motion. Our results suggest that even under the interaction between P-selectin glycoprotein ligand-1 (PSGL-1) and P-selectin, which is mainly responsible for leukocyte rolling, a cell is able to show firm adhesion in a small capillary. These findings may help in understanding such phenomena as leukocyte plugging and cancer metastasis. Copyright © 2016 the American Physiological Society.

Moisture Transfer in Concrete: Numerical Determination of the Capillary Conductivity Coefficient

Directory of Open Access Journals (Sweden)

Simo Elie

2017-03-01

Full Text Available We numerically investigated moisture transfer in buildings made of concrete. We considered three types of concrete: normal concrete, pumice concrete and cellular concrete. We present the results of a 1-D liquid water flow in such materials. We evaluated the moisture distribution in building materials using the Runge-Kutta fourth-and-fifth-order method. The DOPRI5 code was used as an integrator. The model calculated the resulting moisture content and other moisture-dependent physical parameters. The moisture curves were plotted. The dampness data obtained was utilized for the numerical computation of the coefficient of the capillary conductivity of moisture. Different profiles of this coefficient are represented. Calculations were performed for four different values of the outdoor temperature: -5°C, 0°C, 5°C and 10°C. We determined that the curves corresponding to small time intervals of wetting are associated with great amplitudes of the capillary conductivity . The amplitudes of the coefficient of the capillary conductivity decrease as the time interval increases. High outdoor temperatures induce high amplitudes of the coefficient of the capillary conductivity.

Comparisons Between Histology and Optical Coherence Tomography Angiography of the Periarterial Capillary-Free Zone.

Science.gov (United States)

Balaratnasingam, Chandrakumar; An, Dong; Sakurada, Yoichi; Lee, Cecilia S; Lee, Aaron Y; McAllister, Ian L; Freund, K Bailey; Sarunic, Marinko; Yu, Dao-Yi

2018-05-01

To use the capillary-free zone along retinal arteries, a physiologic area of superficial avascularization, as an anatomic paradigm to investigate the reliability of optical coherence tomography angiography (OCTA) for visualizing the deep retinal circulation. Validity analysis and laboratory investigation. Five normal human donor eyes (mean age 69.8 years) were perfusion-labeled with endothelial antibodies and the capillary networks of the perifovea were visualized using confocal scanning laser microscopy. Regions of the capillary-free zone along the retinal artery were imaged using OCTA in 16 normal subjects (age range 24-51 years). Then, 3 × 3-mm scans were acquired using the RTVue XR Avanti (ver. 2016.1.0.26; Optovue, Inc, Fremont, California, USA), PLEX Elite 9000 (ver. 1.5.0.15909; Zeiss Meditec, Inc, Dublin, California, USA), Heidelberg Spectralis OCT2 (Family acquisition module 6.7.21.0; Heidelberg Engineering, Heidelberg, Germany), and DRI-OCT Triton (Ver. 1.1.1; Topcon Corp, Tokyo, Japan). Images of the superficial plexus, deep vascular plexus, and a slab containing all vascular plexuses were generated using manufacturer-recommended default settings. Comparisons between histology and OCTA were performed. Histologic analysis revealed that the capillary-free zone along the retinal artery was confined to the plane of the superficial capillary plexus and did not include the intermediate and deep capillary plexuses. Images derived from OCTA instruments demonstrated a prominent capillary-free zone along the retinal artery in slabs of the superficial plexus, deep plexus, and all capillary plexuses. The number of deep retinal capillaries seen in the capillary-free zone was significantly greater on histology than on OCTA (P zone as an anatomic paradigm, we show that the deep vascular beds of the retina are not completely visualized using OCTA. This may be a limitation of current OCTA techniques. Copyright © 2018 Elsevier Inc. All rights reserved.

A novel in situ strategy for the preparation of a β-cyclodextrin/polydopamine-coated capillary column for capillary electrochromatography enantioseparations.

Science.gov (United States)

Guo, Heying; Niu, Xiaoying; Pan, Congjie; Yi, Tao; Chen, Hongli; Chen, Xingguo

2017-06-01

Inspired by the chiral recognition ability of β-cyclodextrin and the natural adhesive properties of polydopamine under alkaline conditions, in this study, a rapid and in situ modification strategy was developed to fabricate β-cyclodextrin/polydopamine composite material coated-capillary columns for open tubular capillary electrochromatography. The results of scanning electron microscopy, FTIR spectroscopy, streaming potential, and electro-osmotic flow studies indicated that β-cyclodextrin/polydopamine was successfully fixed on the inner wall of the capillary column. This coating can be achieved within 1 h affording a greatly reduced capillary preparation time. The performance of the β-cyclodextrin/polydopamine-coated capillary was validated by the analysis of seven pairs of chiral analytes, namely epinephrine, norepinephrine, isoprenaline, terbutaline, verapamil, tryptophane, carvedilol. Good enantioseparation efficiencies were achieved for all. For three consecutive runs, the relative standard deviations for the migration times of the analytes for intraday, interday, and column-to-column repeatability were in the range of 0.41-1.74, 1.03-4.18, and 1.66-8.24%, respectively. Moreover, the separation efficiency of the β-cyclodextrin/polydopamine-coated capillary column did not decrease obviously over 90 runs. The strategy should also be feasible to introduce and immobilize other chiral selectors on the inner walls surface of capillary columns. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Intramedullary capillary haemangioma.

LENUS (Irish Health Repository)

Kelleher, T

2012-02-03

Intramedullary capillary haemangioma is extremely rare and only four cases have been previously reported. We describe a further case, outlining the clinical, radiological, surgical and pathological features.

Colloid mobilization and transport during capillary fringe fluctuations.

Science.gov (United States)

Aramrak, Surachet; Flury, Markus; Harsh, James B; Zollars, Richard L

2014-07-01

Capillary fringe fluctuations due to changing water tables lead to displacement of air-water interfaces in soils and sediments. These moving air-water interfaces can mobilize colloids. We visualized colloids interacting with moving air-water interfaces during capillary fringe fluctuations by confocal microscopy. We simulated capillary fringe fluctuations in a glass-bead-filled column. We studied four specific conditions: (1) colloids suspended in the aqueous phase, (2) colloids attached to the glass beads in an initially wet porous medium, (3) colloids attached to the glass beads in an initially dry porous medium, and (4) colloids suspended in the aqueous phase with the presence of a static air bubble. Confocal images confirmed that the capillary fringe fluctuations affect colloid transport behavior. Hydrophilic negatively charged colloids initially suspended in the aqueous phase were deposited at the solid-water interface after a drainage passage, but then were removed by subsequent capillary fringe fluctuations. The colloids that were initially attached to the wet or dry glass bead surface were detached by moving air-water interfaces in the capillary fringe. Hydrophilic negatively charged colloids did not attach to static air-bubbles, but hydrophobic negatively charged and hydrophilic positively charged colloids did. Our results demonstrate that capillary fringe fluctuations are an effective means for colloid mobilization.

Capillary contact angle in a completely wet groove.

Science.gov (United States)

Parry, A O; Malijevský, A; Rascón, C

2014-10-03

We consider the phase equilibria of a fluid confined in a deep capillary groove of width L with identical side walls and a bottom made of a different material. All walls are completely wet by the liquid. Using density functional theory and interfacial models, we show that the meniscus separating liquid and gas phases at two phase capillary coexistence meets the bottom capped end of the groove at a capillary contact angle θ(cap)(L) which depends on the difference between the Hamaker constants. If the bottom wall has a weaker wall-fluid attraction than the side walls, then θ(cap) > 0 even though all the isolated walls are themselves completely wet. This alters the capillary condensation transition which is now first order; this would be continuous in a capped capillary made wholly of either type of material. We show that the capillary contact angle θ(cap)(L) vanishes in two limits, corresponding to different capillary wetting transitions. These occur as the width (i) becomes macroscopically large, and (ii) is reduced to a microscopic value determined by the difference in Hamaker constants. This second wetting transition is characterized by large scale fluctuations and essential critical singularities arising from marginal interfacial interactions.

Capillary arterialization requires the bone-marrow-derived cell (BMC)-specific expression of chemokine (C-C motif) receptor-2, but BMCs do not transdifferentiate into microvascular smooth muscle.

Science.gov (United States)

Nickerson, Meghan M; Burke, Caitlin W; Meisner, Joshua K; Shuptrine, Casey W; Song, Ji; Price, Richard J

2009-01-01

Chemokine (C-C motif) receptor-2 (CCR2) regulates arteriogenesis and angiogenesis, facilitating the MCP-1-dependent recruitment of growth factor-secreting bone marrow-derived cells (BMCs). Here, we tested the hypothesis that the BMC-specific expression of CCR2 is also required for new arteriole formation via capillary arterialization. Following non-ischemic saphenous artery occlusion, we measured the following in gracilis muscles: monocyte chemotactic protein-1 (MCP-1) in wild-type (WT) C57Bl/6J mice by ELISA, and capillary arterialization in WT-WT and CCR2(-/-)-WT (donor-host) bone marrow chimeric mice, as well as BMC transdifferentiation in EGFP(+)-WT mice, by smooth muscle (SM) alpha-actin immunochemistry. MCP-1 levels were significantly elevated 1 day after occlusion in WT mice. In WT-WT mice at day 7, compared to sham controls, arterial occlusion induced a 34% increase in arteriole length density, a 46% increase in SM alpha-actin(+) vessels, and a 45% increase in the fraction of vessels coated with SM alpha-actin, indicating significant capillary arterialization. However, in CCR2(-/-)-WT mice, no differences were observed between arterial occlusion and sham surgery. In EGFP(+)-WT mice, EGFP and SM alpha-actin never colocalized. We conclude that BMC-specific CCR2 expression is required for skeletal muscle capillary arterialization following arterial occlusion; however, BMCs do not transdifferentiate into smooth muscle.

Usefulness of vitamin A binding protein as a marker for capillary endothelial permeability

Energy Technology Data Exchange (ETDEWEB)

Ishizaka, Akitoshi; Suzuki, Yukio; Kanazawa, Minoru; Kubo, Atsushi; Kawashiro, Takeo [Keio Univ., Tokyo (Japan). School of Medicine

1992-06-01

We performed a preliminary study to assess the usefulness of Vitamin A binding protein (VABP) as a gamma-camera marker for capillary endothelial permeability. We used a guinea pig model of endotoxin (LPS) induced acute lung injury. We calculated the concentration ratio of either {sup 125}I-albumin or {sup 125}I-VABP in lung tissue to that in plasma (tissue plasma ratio; T/P) as a parameter of capillary endothelial permeability. {sup 99m}Tc-diethylene triamine pentaacetic acid (DTPA) was used as marker for pulmonary interstitial volume. We estimated wet to dry lung weight ratio as a parameter of lung water accumulation (W/D). LPS increased the T/P of {sup 125}I-albumin and W/D, suggesting the development of permeability edema. The T/P for {sup 125}I-VABP was also increased, indicating that {sup 125}I-VABP can be used to detect elevated capillary endothelial permeability. In both groups, LPS and saline, the T/P was higher for {sup 125}I-VABP than for {sup 125}I-albumin. These data suggest that the pulmonary capillary endothelium is more permeable to VABP than albumin. (author).

Capillary blood sampling: national recommendations on behalf of the Croatian Society of Medical Biochemistry and Laboratory Medicine.

Science.gov (United States)

Krleza, Jasna Lenicek; Dorotic, Adrijana; Grzunov, Ana; Maradin, Miljenka

2015-01-01

Capillary blood sampling is a medical procedure aimed at assisting in patient diagnosis, management and treatment, and is increasingly used worldwide, in part because of the increasing availability of point-of-care testing. It is also frequently used to obtain small blood volumes for laboratory testing because it minimizes pain. The capillary blood sampling procedure can influence the quality of the sample as well as the accuracy of test results, highlighting the need for immediate, widespread standardization. A recent nationwide survey of policies and practices related to capillary blood sampling in medical laboratories in Croatia has shown that capillary sampling procedures are not standardized and that only a small proportion of Croatian laboratories comply with guidelines from the Clinical Laboratory Standards Institute (CLSI) or the World Health Organization (WHO). The aim of this document is to provide recommendations for capillary blood sampling. This document has been produced by the Working Group for Capillary Blood Sampling within the Croatian Society of Medical Biochemistry and Laboratory Medicine. Our recommendations are based on existing available standards and recommendations (WHO Best Practices in Phlebotomy, CLSI GP42-A6 and CLSI C46-A2), which have been modified based on local logistical, cultural, legal and regulatory requirements. We hope that these recommendations will be a useful contribution to the standardization of capillary blood sampling in Croatia.

Viscosity measurement in the capillary tube viscometer under unsteady flow

International Nuclear Information System (INIS)

Park, Heung Jun; Yoo, Sang Sin; Suh, Sang Ho

2000-01-01

The objective of the present study is to develop a new device that the viscous characteristics of fluids are determined by applying the unsteady flow concept to the traditional capillary tube viscometer. The capillary tube viscometer consists of a small cylindrical reservoir, capillary tube, a load cell system that measures the mass flow rate, interfaces, and computer. Due to the small size of the reservoir the height of liquid in the reservoir decreases as soon as the liquid in the reservoir drains out through the capillary and the mass flow rate in the capillary decreases as the hydrostatic pressure in the reservoir decreases resulting in a decrease of the shear rate in the capillary tube. The instantaneous shear rate and driving force in the capillary tube are determined by measuring the mass flow rate through the capillary, and the fluid viscosity is determined from the measured flow rate and the driving force

Functional and chemical stability of a medicinal herb, Artemisia capillaris, following gamma sterilization

Energy Technology Data Exchange (ETDEWEB)

Jung, Uhee; Jeong, Ill Yun; Bae, Mun Hyoung; Byun, Myung Woo; Jo, Sung Kee [Radiation Research Center for Biotechnology, Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of)

2007-08-15

The stability of functional and chemical properties of gamma-irradiated (10 kGy) Artemisia capillaris, a widely used herb in the traditional Oriental medicine, was investigated. Functional properties of the extracts of gamma-irradiated and non-irradiated A. capillaris were compared in antioxidant activities, such as 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical and superoxide anion radical scavenging, lipid peroxidation inhibition, and protection of lymphocyte and plasmid DNA. Their chemical properties were assessed by HPLC analysis, comparing with chlorogenic acid and caffeic acid, which were isolated from ethylacetate fraction as major compounds with strong antioxidant activities. No significant difference in functional properties between irradiated and non-irradiated A. capillaris was found in all antioxidant assays. Also HPLC analysis of ethyl acetate fractions of irradiated and non-irradiated A. capillaris revealed the preservation of chlorogenic acid ({sub t}R=3.124 min) and caffeic acid ({sub t}R=3.672 min), and showed almost the same pattern in the general peaks. These results suggest that the chemical components and antioxidant properties of A. capillaris are not affected largely by gamma-ray irradiation. Therefore, this study may provide evidence that the irradiated herbs retain their potential functional properties.

Single injection 51Cr EDTA plasma clearance determination in children using capillary blood samples

International Nuclear Information System (INIS)

Broechner-Mortensen, J.; Christoffersen, J.

1977-01-01

The reliability of a determination of the total 51 Cr EDTA plasma clearance (e) (and with it the glomerular filtration rate), by a simplified single injection method (injected dose: 4.5 μCi per kg b.w.) using capillary blood samples (0.2 ml), was investigated in twenty children. Clearance values determined from capillary blood samples did not differ significantly from those measured simultaneously from venous blood samples, the mean ratio+-SD being 1.02+-0.06(n = 10). The reproducibility (total day-to-day variation) of E determined from capillary blood samples was 6.7% in children with decreased renal function (n = 3) and 6.9% in children with normal renal function (n = 7). The present data indicate that the use of capillary blood samples is an accurate and very precise approach for determination of E in children. (Auth.)

Insulin-induced capillary recruitment is impaired in both lean and obese women with PCOS.

Science.gov (United States)

Ketel, I J G; Serné, E H; Ijzerman, R G; Korsen, T J M; Twisk, J W; Hompes, P G A; Smulders, Y M; Homburg, R; Vorstermans, L; Stehouwer, C D A; Lambalk, C B

2011-11-01

Insulin resistance, i.e. impaired insulin-mediated glucose uptake (IMGU), is a major risk factor for type 2 diabetes in women with polycystic ovary syndrome (PCOS). Insulin-induced capillary recruitment (IICR) is considered a significant determinant of IMGU. We investigated whether IICR is a determinant IMGU in obese and lean women with and without PCOS. The study included 36 women with PCOS (20 lean, BMI 21.9 ± 2.3 kg/m(2) and 16 obese, BMI 35.9 ± 6.0 kg/m(2)) and 27 age-matched healthy controls (14 lean, BMI 22.2 ± 1.8 kg/m(2) and 13 obese, BMI 40.5 ± 7.0 kg/m(2)). IICR was evaluated by capillary microscopy during an isoglycemic-hyperinsulinemic clamp. IMGU was expressed as M/I value. The M/I value was significantly lower in obese PCOS women compared with obese controls [0.5 (0.2-1.1) versus 0.8 (0.3-1.4) (mg kg(-1) min(-1) pmol l(-1)) × 100, P lean PCOS and lean control women was non-significant [1.5 (0.5-2.6) versus 1.7 (1.0-3.7) (mg kg(-1) min(-1) pmol l(-1)) × 100, P = 0.17]. Hyperinsulinemia increased capillary recruitment in lean controls (53.5 ± 20.3 versus 64.9 ± 27.4 n/mm(2), P PCOS group nor in obese controls. IICR and androgens were a determinant of M/I value only in lean women with or without PCOS. PCOS per se is associated with impaired IICR. Obese women with PCOS, in part independent of obesity, demonstrated a profound insulin resistance, whereas the difference between lean PCOS women and healthy controls was small and statistically non-significant. IICR was a determinant of IMGU in lean, but not in obese, women regardless of the presence of PCOS.

Genetic modification of mesenchymal stem cells overexpressing CCR1 increases cell viability, migration, engraftment, and capillary density in the injured myocardium.

Science.gov (United States)

Huang, Jing; Zhang, Zhiping; Guo, Jian; Ni, Aiguo; Deb, Arjun; Zhang, Lunan; Mirotsou, Maria; Pratt, Richard E; Dzau, Victor J

2010-06-11

Although mesenchymal stem cell (MSC) transplantation has been shown to promote cardiac repair in acute myocardial injury in vivo, its overall restorative capacity appears to be restricted mainly because of poor cell viability and low engraftment in the ischemic myocardium. Specific chemokines are upregulated in the infarcted myocardium. However the expression levels of the corresponding chemokine receptors (eg, CCR1, CXCR2) in MSCs are very low. We hypothesized that this discordance may account for the poor MSC engraftment and survival. To determine whether overexpression of CCR1 or CXCR2 chemokine receptors in MSCs augments their cell survival, migration and engraftment after injection in the infarcted myocardium. Overexpression of CCR1, but not CXCR2, dramatically increased chemokine-induced murine MSC migration and protected MSC from apoptosis in vitro. Moreover, when MSCs were injected intramyocardially one hour after coronary artery ligation, CCR1-MSCs accumulated in the infarcted myocardium at significantly higher levels than control-MSCs or CXCR2-MSCs 3 days postmyocardial infarction (MI). CCR1-MSC-injected hearts exhibited a significant reduction in infarct size, reduced cardiomyocytes apoptosis and increased capillary density in injured myocardium 3 days after MI. Furthermore, intramyocardial injection of CCR1-MSCs prevented cardiac remodeling and restored cardiac function 4 weeks after MI. Our results demonstrate the in vitro and in vivo salutary effects of genetic modification of stem cells. Specifically, overexpression of chemokine receptor enhances the migration, survival and engraftment of MSCs, and may provide a new therapeutic strategy for the injured myocardium.

Capillary condensation between disks in two dimensions

DEFF Research Database (Denmark)

Gil, Tamir; Ipsen, John Hjorth

1997-01-01

Capillary condensation between two two-dimensional wetted circular substrates (disks) is studied by an effective free energy description of the wetting interface. The interfacial free-energy potential is developed on the basis of the theory for the wetting of a single disk, where interfacial...... capillary fluctuations play a dominant role. A simple approximative analytical expression of the interfacial free energy is developed and is validated numerically. The capillary condensation is characterized by the analysis of the coverage of the condensed phase, its stability, and asymptotic behaviors...

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

Science.gov (United States)

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.

Generalized polymer effective charge measurement by capillary isotachophoresis.

Science.gov (United States)

Chamieh, Joseph; Koval, Dušan; Besson, Adeline; Kašička, Václav; Cottet, Hervé

2014-11-28

In this work, we have generalized the use of capillary isotachophoresis as a universal method for determination of effective charge of anionic and cationic (co)polymers on ordinary capillary electrophoresis instruments. This method is applicable to a broad range of strong or weak polyelectrolytes with good repeatability. Experimental parameters (components and concentrations of leading and terminating electrolytes, capillary diameters, constant electric current intensity) were optimized for implementation in 100 μm i.d. capillaries for both polyanions and polycations. Determined values of polymer effective charge were in a very good agreement with those obtained by capillary electrophoresis with indirect UV detection. Uncertainty of the effective charge measurement using isotachophoresis was addressed and estimated to be ∼5-10% for solutes with mobilities in the 20-50 × 10(-9)m(2)V(-1)s(-1) range. Copyright © 2014 Elsevier B.V. All rights reserved.

Isotherms of Capillary Condensation Influenced by Formation of Adsorption Films.

Science.gov (United States)

Churaev; Starke; Adolphs

2000-01-15

Isotherms of capillary condensation are often used to determine the vapor sorption capacity of porous adsorbents as well as the pore size distribution by radii. In this paper, for calculating the volume of capillary condensate and of adsorption films in a porous body, an approach based on the theory of surface forces is used. Adsorption isotherms and disjoining pressure isotherms of wetting films are presented here in an exponential form discussed earlier. The calculations were made for straight cylindrical capillaries of different radii and slit pores of different width. The mechanisms of capillary condensation differ in cylindrical and slit pores. In cylindrical pores capillary condensation occurs due to capillary instability of curved wetting films on a capillary surface, when film thickness grows. In the case of slit pores, coalescence of wetting films formed on opposite slit surfaces proceeds under the action of attractive dispersion forces. Partial volumes of liquid in the state of both capillary condensate and adsorbed films are calculated dependent on the relative vapor pressure in a surrounding media. Copyright 2000 Academic Press.

Geometry Effects of Capillary on the Evaporation from the Meniscus

International Nuclear Information System (INIS)

Choi, Choong Hyo; Jin, Song Wan; Yoo, Jung Yul

2007-01-01

The effect of capillary cross-section geometry on evaporation is investigated in terms of the meniscus shape, evaporation rate and evaporation-induced flow for circular, square and rectangular cross-sectional capillaries. The shapes of water and ethanol menisci are not much different from each other in square and rectangular capillaries even though the surface tension of water is much larger than that of ethanol. On the other hand, the shapes of water and ethanol menisci are very different from each other in circular capillary. The averaged evaporation fluxes in circular and rectangular capillaries are measured by tracking the meniscus position. At a given position, the averaged evaporation flux in rectangular capillaries in much larger than that in circular capillary with comparable hydraulic diameter. The flow near the evaporating meniscus is also measured using micro-PIV, so that the rotating vortex motion is observed near the evaporating ethanol and methanol menisci except for the case of methanol meniscus in rectangular capillary. This difference is considered to be due to the existence of corner menisci at the four corners

Large abnormal peak on capillary zone electrophoresis due to contrast agent.

Science.gov (United States)

Wheeler, Rachel D; Zhang, Liqun; Sheldon, Joanna

2017-01-01

Background Some iodinated radio-contrast media absorb ultraviolet light and can therefore be detected by capillary zone electrophoresis. If seen, these peaks are typically small with 'quantifications' of below 5 g/L. Here, we describe the detection of a large peak on capillary zone electrophoresis that was due to the radio-contrast agent, Omnipaque™. Methods Serum from a patient was analysed by capillary zone electrophoresis, and the IgG, IgA, IgM and total protein concentrations were measured. The serum sample was further analysed by gel electrophoresis and immunofixation. Results Capillary zone electrophoresis results for the serum sample showed a large peak with a concentration high enough to warrant urgent investigation. However, careful interpretation alongside the serum immunoglobulin concentrations and total protein concentration showed that the abnormal peak was a pseudoparaprotein rather than a monoclonal immunoglobulin. This was confirmed by analysis with gel electrophoresis and also serum immunofixation. The patient had had a CT angiogram with the radio-contrast agent Omnipaque™; addition of Omnipaque™ to a normal serum sample gave a peak with comparable mobility to the pseudoparaprotein in the patient's serum. Conclusions Pseudoparaproteins can appear as a large band on capillary zone electrophoresis. This case highlights the importance of a laboratory process that detects significant electrophoretic abnormalities promptly and interprets them in the context of the immunoglobulin concentrations. This should avoid incorrect reporting of pseudoparaproteins which could result in the patient having unnecessary investigations.

Parametric study of a capillary tube-suction line heat exchanger in a transcritical CO2 heat pump cycle

International Nuclear Information System (INIS)

Agrawal, Neeraj; Bhattacharyya, Souvik

2008-01-01

The capillary tube in a transcritical CO 2 system behaves differently as temperature and pressure are two independent parameters unlike those in a sub-critical cycle. A capillary tube-suction line heat exchanger (CL-SLHX) in a transcritical vapour compression cycle considering homogeneous two-phase flow is modelled in this study based on mass, energy and momentum equations. Effects of gas cooler temperature, evaporator temperature and internal diameter of capillary tube are investigated. Heat transfer rate is observed to be influenced by refrigerant quality, mass flow rate and the prevailing temperature difference. Heat transfer rate variation with gas cooler temperature is unique, recording an initial increase followed by a decrease. Frictional pressure drop influences the heat transfer; consequently, chances of re-condensation of refrigerant vapour are very marginal. Larger diameter of capillary tube leads to increase in refrigerant mass flow rate and increase in heat transfer rate as well. Shorter inlet adiabatic capillary length with larger heat exchanger length is better for heat transfer. This study is an attempt to dispel the scepticism prevailing in transcritical CO 2 system community overemphasising the need for a throttle valve to control the optimum discharge pressure

Nationwide survey of policies and practices related to capillary blood sampling in medical laboratories in Croatia.

Science.gov (United States)

Krleza, Jasna Lenicek

2014-01-01

Capillary sampling is increasingly used to obtain blood for laboratory tests in volumes as small as necessary and as non-invasively as possible. Whether capillary blood sampling is also frequent in Croatia, and whether it is performed according to international laboratory standards is unclear. All medical laboratories that participate in the Croatian National External Quality Assessment Program (N = 204) were surveyed on-line to collect information about the laboratory's parent institution, patient population, types and frequencies of laboratory tests based on capillary blood samples, choice of reference intervals, and policies and procedures specifically related to capillary sampling. Sampling practices were compared with guidelines from the Clinical and Laboratory Standards Institute (CLSI) and the World Health Organization (WHO). Of the 204 laboratories surveyed, 174 (85%) responded with complete questionnaires. Among the 174 respondents, 155 (89%) reported that they routinely perform capillary sampling, which is carried out by laboratory staff in 118 laboratories (76%). Nearly half of respondent laboratories (48%) do not have a written protocol including order of draw for multiple sampling. A single puncture site is used to provide capillary blood for up to two samples at 43% of laboratories that occasionally or regularly perform such sampling. Most respondents (88%) never perform arterialisation prior to capillary blood sampling. Capillary blood sampling is highly prevalent in Croatia across different types of clinical facilities and patient populations. Capillary sampling procedures are not standardised in the country, and the rate of laboratory compliance with CLSI and WHO guidelines is low.

Gas revenue increasingly significant

International Nuclear Information System (INIS)

Megill, R.E.

1991-01-01

This paper briefly describes the wellhead prices of natural gas compared to crude oil over the past 70 years. Although natural gas prices have never reached price parity with crude oil, the relative value of a gas BTU has been increasing. It is one of the reasons that the total amount of money coming from natural gas wells is becoming more significant. From 1920 to 1955 the revenue at the wellhead for natural gas was only about 10% of the money received by producers. Most of the money needed for exploration, development, and production came from crude oil. At present, however, over 40% of the money from the upstream portion of the petroleum industry is from natural gas. As a result, in a few short years natural gas may become 50% of the money revenues generated from wellhead production facilities

Reverse capillary flow of condensed water through aligned multiwalled carbon nanotubes

International Nuclear Information System (INIS)

Yun, Jongju; Jeon, Wonjae; Alam Khan, Fakhre; Lee, Jinkee; Baik, Seunghyun

2015-01-01

Molecular transport through nanopores has recently received considerable attention as a result of advances in nanofabrication and nanomaterial synthesis technologies. Surprisingly, water transport investigations through carbon nanochannels resulted in two contradicting observations: extremely fast transport or rejection of water molecules. In this paper, we elucidate the mechanism of impeded water vapor transport through the interstitial space of aligned multiwalled carbon nanotubes (aligned-MWCNTs)—capillary condensation, agglomeration, reverse capillary flow, and removal by superhydrophobicity at the tip of the nanotubes. The origin of separation comes from the water’s phase change from gas to liquid, followed by reverse capillary flow. First, the saturation water vapor pressure is decreased in a confined space, which is favorable for the phase change of incoming water vapor into liquid drops. Once continuous water meniscus is formed between the nanotubes by the adsoprtion and agglomeration of water molecules, a high reverse Laplace pressure is induced in the mushroom-shaped liquid meniscus at the entry region of the aligned-MWCNTs. The reverse Laplace pressure can be significantly enhanced by decreasing the pore size. Finally, the droplets pushed backward by the reverse Laplace pressure can be removed by superhydrophobicity at the tip of the aligned-MWCNTs. The analytical analysis was also supported by experiments carried out using 4 mm-long aligned-MWCNTs with different intertube distances. The water rejection rate and the separation factor increased as the intertube distance decreased, resulting in 90% and 10, respectively, at an intertube distance of 4 nm. This mechanism and nanotube membrane may be useful for energy-efficient water vapor separation and dehumidification. (paper)

The Texas horned lizard as model for robust capillary structures for passive directional transport of cooling lubricants

Science.gov (United States)

Comanns, Philipp; Winands, Kai; Pothen, Mario; Bott, Raya A.; Wagner, Hermann; Baumgartner, Werner

2016-04-01

Moisture-harvesting lizards, such as the Texas horned lizard Phrynosoma cornutum, have remarkable adaptations for inhabiting arid regions. Special skin structures, in particular capillary channels in between imbricate overlapping scales, enable the lizard to collect water by capillarity and to transport it to the snout for ingestion. This fluid transport is passive and directional towards the lizard's snout. The directionality is based on geometric principles, namely on a periodic pattern of interconnected half-open capillary channels that narrow and widen. Following a biomimetic approach, these principles were transferred to technical prototype design and manufacturing. Capillary structures, 50 μm to 300 μm wide and approx. 70 μm deep, were realized by use of a pulsed picosecond laser in hot working tool steel, hardened to 52 HRC. In order to achieve highest functionality, strategies were developed to minimize potential structural inaccuracies, which can occur at the bottom of the capillary structures caused by the laser process. Such inaccuracies are in the range of 10 μm to 15 μm and form sub-capillary structures with greater capillary forces than the main channels. Hence, an Acceleration Compensation Algorithm was developed for the laser process to minimize or even avoid these inaccuracies. The capillary design was also identified to have substantial influence; by a hexagonal capillary network of non-parallel capillaries potential influences of sub-capillaries on the functionality were reduced to realize a robust passive directional capillary transport. Such smart surface structures can lead to improvements of technical systems by decreasing energy consumption and increasing the resource efficiency.

Adsorption isoterms and capillary condensation in a nanoslit with rough walls: a density functional theory.

Science.gov (United States)

Berim, Gersh O; Ruckenstein, Eli

2012-08-07

Adsorption isoterms and capillary condensation in an open slit with walls decorated with arrays of pillars are examined using the density functional theory. Compared with the main substrate, the pillars can have the same or different parameters in the Lennard-Jones interaction potential between them and the fluid in the slit. The roughness of the solid surface, defined as the ratio between the area of the actual surface and the area of the surface free of pillars, is controlled by the height of the pillars. It is shown that the capillary condensation pressure first increases with increasing roughness, passes through a maximum, and then decreases. The amount of adsorbed fluid at constant volume of the slit has, in general, a nonmonotonic dependence on roughness. These features of adsorption and capillary condensation are results of increased surface area and changes in the fluid-solid potential energy due to changes in roughness.

Interfacial layering and capillary roughness in immiscible liquids.

Science.gov (United States)

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.

C-Kit expression in the gallbladder of guinea pig with chronic calculous cholecystitis and the effect of Artemisia capillaris Thunb on interstitial cells of Cajal.

Science.gov (United States)

Feng, Hua; Wang, Fang; Wang, Changmiao

2016-07-01

To study the c-Kit expression in the gallbladder of cholesterol lithogenic guinea pig model and the effect of Artemisia capillaris Thunb on interstitial cells of Cajal (ICCs). A total of 45 guinea pigs were randomly assigned into three groups: the control group (guinea pigs fed a standard diet, normal group); the model group (guinea pigs fed a cholesterol gallstone-inducing diet); and the Chinese medicine group (guinea pigs fed the cholesterol gallstone-inducing diet and treated with A. capillaris through intragastric administration, therapy group). Each group had 15 guinea pigs. The gallbladders of the guinea pigs were harvested after 8 weeks. C-Kit expression was detected using an immunohistochemistry staining, real-time PCR, and Western blot analyses. The effect of A. capillaris on ICCs was evaluated by muscle strip contraction experiments. C-Kit expression significantly decreased in the gallbladder of model group, but increased in the Chinese medicine group. The Contractility of guinea pig gallbladder muscle strip significantly improved in the Chinese medicine group. Our results indicated that A. capillaris improves gallbladder impairment by up-regulating c-Kit expression, and it also can improve the contractile response of in vitro guinea pig gallbladder muscle strips.

Modelization and simulation of capillary barriers

International Nuclear Information System (INIS)

Lisbona Cortes, F.; Aguilar Villa, G.; Clavero Gracia, C.; Gracia Lozano, J.L.

1998-01-01

Among the different underground transport phenomena, that due to water flows is of great relevance. Water flows in infiltration and percolation processes are responsible of the transport of hazardous wastes towards phreatic layers. From the industrial and geological standpoints, there is a great interest in the design of natural devices to avoid the flows transporting polluting substances. This interest is increased when devices are used to isolate radioactive waste repositories, whose life is to be longer than several hundred years. The so-called natural devices are those based on the superimposition of material with different hydraulic properties. In particular, the flow retention in this kind stratified media, in unsaturated conditions, is basically due to the capillary barrier effect, resulting from placing a low conductivity material over another with a high hydraulic conductivity. Covers designed from the effect above have also to allow a drainage of the upper layer. The lower cost of these covers, with respect to other kinds of protection systems, and the stability in time of their components make them very attractive. However, a previous investigation to determine their effectivity is required. In this report we present the computer code BCSIM, useful for easy simulations of unsaturated flows in a capillary barrier configuration with drainage, and which is intended to serve as a tool for designing efficient covers. The model, the numerical algorithm and several implementation aspects are described. Results obtained in several simulations, confirming the effectivity of capillary barriers as a technique to build safety covers for hazardous waste repositories, are presented. (Author)

Applications of on-line weak affinity interactions in free solution capillary electrophoresis

DEFF Research Database (Denmark)

Heegaard, Niels H H; Nissen, Mogens H; Chen, David D Y

2002-01-01

The impressive selectivity offered by capillary electrophoresis can in some cases be further increased when ligands or additives that engage in weak affinity interactions with one or more of the separated analytes are added to the electrophoresis buffer. This on-line affinity capillary...... electrophoresis approach is feasible when the migration of complexed molecules is different from the migration of free molecules and when separation conditions are nondenaturing. In this review, we focus on applying weak interactions as tools to enhance the separation of closely related molecules, e.g., drug...... enantiomers and on using capillary electrophoresis to characterize such interactions quantitatively. We describe the equations for binding isotherms, illustrate how selectivity can be manipulated by varying the additive concentrations, and show how the methods may be used to estimate binding constants. On...

Capillary array electrophoresis using laser-excited confocal fluorescence detection

Energy Technology Data Exchange (ETDEWEB)

Huang, X.C.; Quesada, M.A.; Mathies, R.A. [Univ. of California, Berkeley, CA (United States)

1992-04-15

Capillary electrophoresis (CE) has found widespread application in analytical and biomedical research, and the scope and sophistication of CE is still rapidly advancing. Gel-filled capillaries have been employed for the rapid separation and analysis of synthetic polynucleotides, DNA sequencing fragments, and DNA restriction fragments. Open-tube capillary electrophoresis has attained subattomole detection levels in amino acid separations 14 and proven its utility for the separation of proteins, viruses, and bacteria. Separation of the optical isomers of dansyl amino acids has also been successfully demonstrated. Micellar electrokinetic capillary chromatography, isoelectric focusing, and on-column derivatization can all be performed on CE columns, demonstrating the utility of capillary electrophoresis as an analytical and micropreparative tool. 29 refs., 6 figs., 1 tab.

Capillary Rise: Validity of the Dynamic Contact Angle Models.

Science.gov (United States)

Wu, Pingkeng; Nikolov, Alex D; Wasan, Darsh T

2017-08-15

The classical Lucas-Washburn-Rideal (LWR) equation, using the equilibrium contact angle, predicts a faster capillary rise process than experiments in many cases. The major contributor to the faster prediction is believed to be the velocity dependent dynamic contact angle. In this work, we investigated the dynamic contact angle models for their ability to correct the dynamic contact angle effect in the capillary rise process. We conducted capillary rise experiments of various wetting liquids in borosilicate glass capillaries and compared the model predictions with our experimental data. The results show that the LWR equations modified by the molecular kinetic theory and hydrodynamic model provide good predictions on the capillary rise of all the testing liquids with fitting parameters, while the one modified by Joos' empirical equation works for specific liquids, such as silicone oils. The LWR equation modified by molecular self-layering model predicts well the capillary rise of carbon tetrachloride, octamethylcyclotetrasiloxane, and n-alkanes with the molecular diameter or measured solvation force data. The molecular self-layering model modified LWR equation also has good predictions on the capillary rise of silicone oils covering a wide range of bulk viscosities with the same key parameter W(0), which results from the molecular self-layering. The advantage of the molecular self-layering model over the other models reveals the importance of the layered molecularly thin wetting film ahead of the main meniscus in the energy dissipation associated with dynamic contact angle. The analysis of the capillary rise of silicone oils with a wide range of bulk viscosities provides new insights into the capillary dynamics of polymer melts.

Vacuum scanning capillary photoemission microscopy.

Science.gov (United States)

Aseyev, S A; Cherkun, A P; Mironov, B N; Petrunin, V V; Chekalin, S V

2017-08-01

We demonstrate the use of a conical capillary in a scanning probe microscopy for surface analysis. The probe can measure photoemission from a substrate by transmitting photoelectrons along the capillary as a function of probe position. The technique is demonstrated on a model substrate consisting of a gold reflecting layer on a compact disc which has been illuminated by an unfocused laser beam with a wavelength 400nm, from a femtosecond laser with a beam size of 4mm. A quartz capillary with a 2-µm aperture has been used in the experiments. The period of gold microstructure, shown to be 1.6µ, was measured by the conical probe operating in shear force mode. In shear force regime, the dielectric capillary has been used as a "classical" SPM tip, which provided images reflecting the surface topology. In a photoelectron regime photoelectrons passed through hollow tip and entered a detector. The spatial distribution of the recorded photoelectrons consisted of periodic mountain-valley strips, resembling the surface profile of the sample. Submicron spatial resolution has been achieved. This approach paves the way to study pulsed photodesorption of large organic molecular ions with high spatial and element resolution using the combination of a hollow-tip scanner with time-of-flight technique. Copyright © 2017 Elsevier B.V. All rights reserved.

Equilibrium capillary forces with atomic force microscopy

NARCIS (Netherlands)

Sprakel, J.H.B.; Besseling, N.A.M.; Leermakers, F.A.M.; Cohen Stuart, M.A.

2007-01-01

We present measurements of equilibrium forces resulting from capillary condensation. The results give access to the ultralow interfacial tensions between the capillary bridge and the coexisting bulk phase. We demonstrate this with solutions of associative polymers and an aqueous mixture of gelatin

Multianalyte detection using a capillary-based flow immunosensor.

Science.gov (United States)

Narang, U; Gauger, P R; Kusterbeck, A W; Ligler, F S

1998-01-01

A highly sensitive, dual-analyte detection system using capillary-based immunosensors has been designed for explosive detection. This model system consists of two capillaries, one coated with antibodies specific for 2,4,6-trinitrotoluene (TNT) and the other specific for hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) combined into a single device. The fused silica capillaries are prepared by coating anti-TNT and anti-RDX antibodies onto the silanized inner walls using a hetero-bifunctional crosslinker. After immobilization, the antibodies are saturated with a suitable fluorophorelabeled antigen. A "T" connector is used to continuously flow the buffer solution through the individual capillaries. To perform the assay, an aliquot of TNT or RDX or a mixture of the two analytes is injected into the continuous flow stream. In each capillary, the target analyte displaces the fluorophore-labeled antigen from the binding pocket of the antibody. The labeled antigen displaced from either capillary is detected downstream using two portable spectrofluorometers. The limits of detection for TNT and RDX in the multi-analyte formate are 44 fmol (100 microliters of 0.1 ng/ml TNT solution) and 224 fmol (100 microliters of 0.5 ng/ml RDX solution), respectively. The entire assay for both analytes can be performed in less than 3 min.

A fully automated 384 capillary array for DNA sequencer. Final report

Energy Technology Data Exchange (ETDEWEB)

Li, Qingbo; Kane, T

2003-03-20

Phase I SpectruMedix has successfully developed an automatic 96-capillary array DNA prototype based on the multiplexed capillary electrophoresis system originated from Ames Laboratory-USDOE, Iowa State University. With computer control of all steps involved in a 96-capillary array running cycle, the prototype instrument (the SCE9600) is now capable of sequencing 450 base pairs (bp) per capillary, or 48,000 bp per instrument run within 2 hrs. Phase II of this grant involved the advancement of the core 96 capillary technologies, as well as designing a high density 384 capillary prototype. True commercialization of the 96 capillary instrument involved finalization of the gel matrix, streamlining the instrument hardware, creating a more reliable capillary cartridge, and further advancement of the data processing software. Together these silos of technology create a truly commercializable product (the SCE9610) capable of meeting the operation needs of the sequencing centers.

The effect of x-rays on the capillaries

Energy Technology Data Exchange (ETDEWEB)

Kaneko, I; Matsushima, H; Yamada, T; Moriya, H [Toho Univ., Tokyo (Japan). School of Medicine; Terumoto, H

1975-06-01

The authors studied the influence of 200 KV X-ray irradiation on the capillaries of the earlobe of mice. They supposed that a great number of the injuries of various tissues by irradiation is caused by the deformation or transformation of the capillaries. In this report, we investigated that vascular injury to the skin of the earlobe. Earlobes of C-57BL mice were used. The field irradiated was 0.7 cm in diameter. The irradiation dose was 1000, 3000, 5000, 7000, and 9000 rad at a single dose of 200 KV X-ray. Injuries were observed by micro-angiography, tissue by specimens, and by microscopic examination of circulating blood in the living irradiated earlobes. Changes of the capillaries were observed (dilatation, constriction, serpignous changes, hypervascular or avascular change), petechiae, epilation, ulcer, dermatitis, etc. These changes occurred in parallel with the dose irradiated, and the irregularities of the circulation were most extensive 3 to 4 weeks after irradiation. After this period, appearance of hypervascular tissue was observed. Four or 5 weeks later, the disorders decreased gradually. However in the groups of 7000 and 9000 rad irradiation, the deformation of constriction and dilatation increased again more than 100 days after irradiation.

Weight-controlled capillary viscometer

Science.gov (United States)

Digilov, Rafael M.; Reiner, M.

2005-11-01

The draining of a water column through a vertical discharge capillary tube is examined with the aid of a force sensor. The change of the mass of the liquid in the column with time is found to be not purely exponential as implied by Poiseuille's law. Using observed residuals associated with a kinetic energy correction, an approximate formula for the mass as a function of time is derived and excellent agreement with experimental data is attained. These results are verified by a viscosity test of distilled water at room temperature. A simple and inexpensive weight-controlled capillary viscometer is proposed that is especially suitable for undergraduate physics and chemistry laboratories.

Capillary electrophoresis: principles and applications in illicit drug analysis.

Science.gov (United States)

Tagliaro, F; Turrina, S; Smith, F P

1996-02-09

Capillary electrophoresis, which appeared in the early 1980s, is now rapidly expanding into many scientific disciplines, including analytical chemistry, biotechnology and biomedical and pharmaceutical sciences. In capillary electrophoresis,electrokinetic separations are carried out in tiny capillaries at high voltages (10-30 kV), thus obtaining high efficiencies (N > 10(5)) and excellent mass sensitivities (down to 10(-18)-10(-20) moles). The main features of capillary electrophoresis are: versatility of application (from inorganic ions to large DNA fragments), use of different separation modes with different selectivity, extremely low demands on sample volume, negligible running costs, possibility of interfacing with different detection systems, ruggedness and simplicity of instrumentation. Capillary electrophoresis applications in forensic sciences have appeared only recently, but are now rapidly growing, particularly in forensic toxicology. The present paper briefly describes the basic principles of capillary electrophoresis, from both the instrumental and analytical points of view. Furthermore, the main applications in the analysis of illicit/controlled drugs in both illicit preparations and biological samples are presented and discussed (43 references). It is concluded that the particular separation mechanism and the high complementarity of this technique to chromatography makes capillary electrophoresis a new powerful tool of investigation in the hands of forensic toxicologists.

Capillary pressure and saturation relations for supercritical CO2 and brine in sand: High-pressure Pc(Sw) controller/meter measurements and capillary scaling predictions

Science.gov (United States)

Tokunaga, Tetsu K.; Wan, Jiamin; Jung, Jong-Won; Kim, Tae Wook; Kim, Yongman; Dong, Wenming

2013-08-01

In geologic carbon sequestration, reliable predictions of CO2 storage require understanding the capillary behavior of supercritical (sc) CO2. Given the limited availability of measurements of the capillary pressure (Pc) dependence on water saturation (Sw) with scCO2 as the displacing fluid, simulations of CO2 sequestration commonly rely on modifying more familiar air/H2O and oil/H2O Pc(Sw) relations, adjusted to account for differences in interfacial tensions. In order to test such capillary scaling-based predictions, we developed a high-pressure Pc(Sw) controller/meter, allowing accurate Pc and Sw measurements. Drainage and imbibition processes were measured on quartz sand with scCO2-brine at pressures of 8.5 and 12.0 MPa (45°C), and air-brine at 21°C and 0.1 MPa. Drainage and rewetting at intermediate Sw levels shifted to Pc values that were from 30% to 90% lower than predicted based on interfacial tension changes. Augmenting interfacial tension-based predictions with differences in independently measured contact angles from different sources led to more similar scaled Pc(Sw) relations but still did not converge onto universal drainage and imbibition curves. Equilibrium capillary trapping of the nonwetting phases was determined for Pc = 0 during rewetting. The capillary-trapped volumes for scCO2 were significantly greater than for air. Given that the experiments were all conducted on a system with well-defined pore geometry (homogeneous sand), and that scCO2-brine interfacial tensions are fairly well constrained, we conclude that the observed deviations from scaling predictions resulted from scCO2-induced decreased wettability. Wettability alteration by scCO2 makes predicting hydraulic behavior more challenging than for less reactive fluids.

Current characteristics of λ -DNA molecules/polystyrene nanoparticles in TBE buffer solution through micro/nanofluidic capillaries under DC electric field

International Nuclear Information System (INIS)

Duan, Yifei; Zhao, Wei; Xue, Jing; Sun, Dan; Wang, Kaige; Wang, Guiren; Bai, Jintao; Li, Junjie; Gu, Changzhi

2017-01-01

In practical applications of biochips and bio-sensors, electrokinetic mechanisms are commonly employed to manipulate single bio-molecules and analyze their characteristics. To accurately and flexibly control the movement of single-molecule within micro/nanofluidic channels which are the basic components of Lab-chips, the current signals in micro/nanocapillaries filled with solutions of DNA molecules or polystyrene (PS) nanoparticles are systematically studied. Experimental results indicate that the current response along the micro/nanocapillaries can be significantly influenced by the diameter of the capillaries and the pH value of the solutions. Specifically, when there is only a pure (TBE) solution, the electric conductance does not monotonically decrease with decreasing the diameter of the capillaries, but slightly increases with decreasing the capillary diameter. When λ -DNA molecules or PS nanoparticles are added into the TBE buffer, the size effect on the electric conductance of the solutions are quite different. Although in the former, the electric conductance behaves differently from that in the pure TBE solution and decreases with the decreasing diameter, in the latter, the change is similar to that in the pure TBE solution. Besides, an abnormal ‘falling’ of the electric conductance is observed in a capillary with diameter of 200 nm. The investigation will significantly enhance the understanding on the electric properties of the solutions of biomolecules and particles in micro/nanofluidics. This is especially helpful for designing functional Lab-chip devices. (paper)

Current characteristics of λ-DNA molecules/polystyrene nanoparticles in TBE buffer solution through micro/nanofluidic capillaries under DC electric field

Science.gov (United States)

Duan, Yifei; Zhao, Wei; Xue, Jing; Sun, Dan; Wang, Kaige; Wang, Guiren; Li, Junjie; Bai, Jintao; Gu, Changzhi

2017-03-01

In practical applications of biochips and bio-sensors, electrokinetic mechanisms are commonly employed to manipulate single bio-molecules and analyze their characteristics. To accurately and flexibly control the movement of single-molecule within micro/nanofluidic channels which are the basic components of Lab-chips, the current signals in micro/nanocapillaries filled with solutions of DNA molecules or polystyrene (PS) nanoparticles are systematically studied. Experimental results indicate that the current response along the micro/nanocapillaries can be significantly influenced by the diameter of the capillaries and the pH value of the solutions. Specifically, when there is only a pure (TBE) solution, the electric conductance does not monotonically decrease with decreasing the diameter of the capillaries, but slightly increases with decreasing the capillary diameter. When λ-DNA molecules or PS nanoparticles are added into the TBE buffer, the size effect on the electric conductance of the solutions are quite different. Although in the former, the electric conductance behaves differently from that in the pure TBE solution and decreases with the decreasing diameter, in the latter, the change is similar to that in the pure TBE solution. Besides, an abnormal ‘falling’ of the electric conductance is observed in a capillary with diameter of 200 nm. The investigation will significantly enhance the understanding on the electric properties of the solutions of biomolecules and particles in micro/nanofluidics. This is especially helpful for designing functional Lab-chip devices.

THE CAPILLARY PATTERN IN HUMAN MASSETER MUSCLE DURING AGEING

Directory of Open Access Journals (Sweden)

Erika Cvetko

2013-10-01

Full Text Available The effect of ageing on the capillary network in skeletal muscles has produced conflicting results in both, human and animals studies. Some of the inconsistencies are due to non-comparable and biased methods that were applied on thin transversal sections, especially in muscles with complicated morphological structures, such as in human masseter muscle. We present a new immunohistochemical method for staining capillaries and muscle fibres in 100 µm thick sections as well as novel approach to 3D visualization of capillaries and muscle fibres. Applying confocal microscopy and virtual 3D stereological grids, or tracing capillaries in virtual reality, length of capillaries within a muscle volume or length of capillaries adjacent to muscle fibre per fibre length, fibre surface or fibre volume were evaluated in masseter muscle of young and old subjects by an unbiased approach. Our findings show that anatomic capillarity is well maintained in masseter muscle in old subjects; however, vascular remodelling occurs with age, which could be a response to changed muscle function and age-related muscle fibre type transformations.

Methyl mercury uptake across bovine brain capillary endothelial cells in vitro: The role of amino acids

International Nuclear Information System (INIS)

Aschner, M.; Clarkson, T.W.

1989-01-01

Previous studies in the rat in vivo have demonstrated that co-injection of methyl mercury (MeHg) with L-cysteine into the common carotid artery enhances brain Hg levels folowing a single capillary pass through the CNS vasculature. In order to elucidate the relationship between MeHg transport and the neutral amino acid transport carrier system, regulatory aspects of MeHg transport across the bovine blood-brain barrier were investigated in isolated brain microvessel preparations. Following 1 hour co-incubations of 203 Hg-MeHgCl with 0.1 mM L-cysteine at 37 deg. C, 203 Hg uptake by suspended microvessels was significantly increased (P 203 Hg was abolished by co-incubations of microvessels with 0.1 mM L-cysteine-L-methionine, or 0.1 mM L-cysteine plus AT-125 (alpha S, 5S)-alpha-amino-3-chloro-4,5-dihydro-5-isoxazolacetic acid), an irreversible inhibitor of gamma-glutamyl-transpeptidase. One hr co-incubations of bovine capilaries with 203 Hg-MeHgCl and 0.1 mM D-cysteine at 37 deg. C or 0.1 mM L-cysteine at 0 deg. did not increase rat of 203 Hg uptake compared with controls. These results indicate that L-cysteine enhances the rate of capillary MeHg uptake. The accumulation of 203 Hg in the bovine microvessels appears to be a carrier-mediated process. It is inhibited by L-methionin, a competitive substrate for neutral amino acid transport, and by AT-125. Capillary uptake of 203 Hg is stereospecific to the L-enantiomorph of cystine, suggesting selective uptake of MeHg across the blood-brain barrier. The data emphasize the relationship between the L-enantiomorph neutral amino acid carrier system and MeHg transport across the capillaries. (author)

Nationwide survey of policies and practices related to capillary blood sampling in medical laboratories in Croatia

Science.gov (United States)

Krleza, Jasna Lenicek

2014-01-01

Introduction: Capillary sampling is increasingly used to obtain blood for laboratory tests in volumes as small as necessary and as non-invasively as possible. Whether capillary blood sampling is also frequent in Croatia, and whether it is performed according to international laboratory standards is unclear. Materials and methods: All medical laboratories that participate in the Croatian National External Quality Assessment Program (N = 204) were surveyed on-line to collect information about the laboratory’s parent institution, patient population, types and frequencies of laboratory tests based on capillary blood samples, choice of reference intervals, and policies and procedures specifically related to capillary sampling. Sampling practices were compared with guidelines from the Clinical and Laboratory Standards Institute (CLSI) and the World Health Organization (WHO). Results: Of the 204 laboratories surveyed, 174 (85%) responded with complete questionnaires. Among the 174 respondents, 155 (89%) reported that they routinely perform capillary sampling, which is carried out by laboratory staff in 118 laboratories (76%). Nearly half of respondent laboratories (48%) do not have a written protocol including order of draw for multiple sampling. A single puncture site is used to provide capillary blood for up to two samples at 43% of laboratories that occasionally or regularly perform such sampling. Most respondents (88%) never perform arterialisation prior to capillary blood sampling. Conclusions: Capillary blood sampling is highly prevalent in Croatia across different types of clinical facilities and patient populations. Capillary sampling procedures are not standardised in the country, and the rate of laboratory compliance with CLSI and WHO guidelines is low. PMID:25351353

An integrated multiple capillary array electrophoresis system for high-throughput DNA sequencing

Energy Technology Data Exchange (ETDEWEB)

Lu, X.

1998-03-27

A capillary array electrophoresis system was chosen to perform DNA sequencing because of several advantages such as rapid heat dissipation, multiplexing capabilities, gel matrix filling simplicity, and the mature nature of the associated manufacturing technologies. There are two major concerns for the multiple capillary systems. One concern is inter-capillary cross-talk, and the other concern is excitation and detection efficiency. Cross-talk is eliminated through proper optical coupling, good focusing and immersing capillary array into index matching fluid. A side-entry excitation scheme with orthogonal detection was established for large capillary array. Two 100 capillary array formats were used for DNA sequencing. One format is cylindrical capillary with 150 {micro}m o.d., 75 {micro}m i.d and the other format is square capillary with 300 {micro}m out edge and 75 {micro}m inner edge. This project is focused on the development of excitation and detection of DNA as well as performing DNA sequencing. The DNA injection schemes are discussed for the cases of single and bundled capillaries. An individual sampling device was designed. The base-calling was performed for a capillary from the capillary array with the accuracy of 98%.

Condensation and Evaporation Transitions in Deep Capillary Grooves

OpenAIRE

Malijevský, A. (Alexandr); Parry, A.O.

2014-01-01

We study the order of capillary condensation and evaporation transitions of a simple fluid adsorbed in a deep capillary groove using a fundamental measure density functional theory (DFT). The walls of the capillary interact with the fluid particles via long-ranged, dispersion, forces while the fluid-fluid interaction is modelled as a truncated Lennard-Jones-like potential. We find that below the wetting temperature $T_w$ condensation is first-order and evaporation is continuous with the metas...

Capillary electrophoretic analysis of synthetic short-chain oligoribonucleotides.

Science.gov (United States)

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.

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

Science.gov (United States)

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.

Application of CHESS single-bounce capillaries at synchrotron beamlines

Science.gov (United States)

Huang, R.; Szebenyi, T.; Pfeifer, M.; Woll, A.; Smilgies, D.-M.; Finkelstein, K.; Dale, D.; Wang, Y.; Vila-Comamala, J.; Gillilan, R.; Cook, M.; Bilderback, D. H.

2014-03-01

Single-bounce capillaries are achromatic X-ray focusing optics that can provide efficient and high demagnification focusing with large numerical apertures. Capillary fabrication at CHESS can be customized according to specific application requirements. Exemplary applications are reviewed in this paper, as well as recent progress on condensers for high-resolution transmission X-ray microscopy and small focal size capillaries.

A Study of Coherent Radiation Generated in an Ablative Capillary Discharge

Directory of Open Access Journals (Sweden)

Jakub Hübner

2013-01-01

Full Text Available Feasible soft-X-ray amplification in the CVI and NVII Balmer transition is investigated in a capillary discharge. The best conditions and parameters for the experimental set-up are found for an ablative capillary. The most optimistic results have shown that the gain would be greater than one, which is the condition for successful ASE (Amplified spontaneous emission in capillary discharges. The capillary discharge evolution is modeled using the NPINCH program, employing a one-dimensional physical model based on MHD equations. The information about the capillary discharge evolution is processed in the FLY, FLYPAPER, FLYSPEC programs, enabling the population to be modeled on specific levels during capillary discharge.

Channeling of neutral particles in micro- and nano-capillaries

International Nuclear Information System (INIS)

Dabagov, S.B.

2003-01-01

After briefly reviewing the main directions in X-ray optics and analyzing the development of capillary optics, a general theory of radiation propagation through capillary structures is described in both geometrical optics and wave optics approximations. Analysis of radiation field structure inside a capillary waveguide shows that wave propagation in channels can be of a purely modal nature, with transmitted energy mostly concentrated in the immediate neighbourhood of capillary inner walls. A qualitative change in radiation scattering with decreasing channel diameter 0 namely, the transition from surface channeling in microcapillaries to bulk channeling in nanocapillaries - is discussed [ru

Performance comparison of capillary and agarose gel electrophoresis for the identification and characterization of monoclonal immunoglobulins.

Science.gov (United States)

McCudden, Christopher R; Mathews, Stephanie P; Hainsworth, Shirley A; Chapman, John F; Hammett-Stabler, Catherine A; Willis, Monte S; Grenache, David G

2008-03-01

The objective of this study was to compare gel- and capillary-based serum protein electrophoresis methods to identify and characterize monoclonal immunoglobulins (M proteins). Five reviewers interpreted 149 consecutively ordered serum specimens following agarose gel electrophoresis (AGE), capillary electrophoresis (CE), immunofixation electrophoresis (IFE), and subtraction immunotyping (IT). As a screening test for detecting M proteins, AGE and CE displayed similar sensitivity (91% and 92%, respectively). CE was less specific (74%) than AGE (81%). An analysis of interinterpreter agreement revealed that interpretations were more consistent using gel-based methods than capillary-based methods, with 80% of the gel interpretations being in complete (5/5) agreement compared with 67% of the capillary interpretations. After implementing the capillary-based methods, the number of tests per reportable result increased (from 1.58 to 1.73). CE is an analytically suitable alternative to AGE, but laboratories implementing it will need to continue IFE testing to characterize all M proteins detected by CE.

Short-term hyperglycemia increases endothelial glycocalyx permeability and acutely decreases lineal density of capillaries with flowing red blood cells

NARCIS (Netherlands)

Zuurbier, Coert J.; Demirci, Cihan; Koeman, Anneke; Vink, Hans; Ince, Can

2005-01-01

Hyperglycemia is becoming recognized as an important risk factor for microvascular dysfunction. We hypothesized that short-term hyperglycemia, either on the scale of hours or weeks, alters the barrier function and the volume of the endothelial glycocalyx and decreases functional capillary density

X-ray Talbot interferometry with capillary plates

International Nuclear Information System (INIS)

Momose, Atsushi; Kawamoto, Shinya

2006-01-01

An X-ray Talbot interferometer consisting of two capillary plates, which were used as X-ray amplitude gratings, was evaluated for X-ray phase imaging. A theoretical aspect of capillary X-ray Talbot interferometry is presented with a preliminary operation result using synchrotron radiation. A two-dimensional X-ray Talbot effect, or self-imaging effect, which was the basis of Talbot interferometry, was observed with the capillary plate, and moire images formed by the X-ray Talbot interferometer exhibited contrasts corresponding to the differential phase shift caused by phase objects placed in front of the interferometer. Finally, the possibility of quantitative phase measurement with a fringe scanning technique is discussed. (author)

Capillary Optics as an x-ray Condensing Lens An Alignment

CERN Document Server

Cappuccio, G

2000-01-01

The procedure of capillary lens alignment is described in detail. The theoretical basis of capillary optics is given in the framework of a comparative analysis of monocapillary and polycapillary optics. The results of x-ray $9 distribution scanning behind the capillary lens for various angle planes, together with the tting results, are presented. A qualitative explanation is given for the discrepancy between the expected and observed divergences of x-ray $9 beams transmitted by the capillary lens.

APPLICABILITY ANALYSIS OF THE PHASE CORRELATION ALGORITHM FOR STABILIZATION OF VIDEO FRAMES SEQUENCES FOR CAPILLARY BLOOD FLOW

Directory of Open Access Journals (Sweden)

K. A. Karimov

2016-05-01

Full Text Available Videocapillaroscopy is a convenient and non-invasive method of blood flow parameters recovery in the capillaries. Capillaries position can vary at recorded video sequences due to the registration features of capillary blood flow. Stabilization algorithm of video capillary blood flow based on phase correlation is proposed and researched. This algorithm is compared to the known algorithms of video frames stabilization with full-frame superposition and with key points. Programs, based on discussed algorithms, are compared under processing the experimentally recorded video sequences of human capillaries and under processing of computer-simulated sequences of video frames with the specified offset. The full-frame superposition algorithm provides high quality of stabilization; however, the program based on this algorithm requires significant computational resources. Software implementation of the algorithm based on the detection of the key points is characterized by good performance, but provides low quality of stabilization for video sequences capillary blood flow. Algorithm based on phase correlation method provides high quality of stabilization and program realization of this algorithm requires minimal computational resources. It is shown that the phase correlation algorithm is the most useful for stabilization of video sequences for capillaries blood flow. Obtained findings can be used in the software for biomedical diagnostics.

Paper Capillary Enables Effective Sampling for Microfluidic Paper Analytical Devices.

Science.gov (United States)

Shangguan, Jin-Wen; Liu, Yu; Wang, Sha; Hou, Yun-Xuan; Xu, Bi-Yi; Xu, Jing-Juan; Chen, Hong-Yuan

2018-06-06

Paper capillary is introduced to enable effective sampling on microfluidic paper analytical devices. By coupling mac-roscale capillary force of paper capillary and microscale capillary forces of native paper, fluid transport can be flexibly tailored with proper design. Subsequently, a hybrid-fluid-mode paper capillary device was proposed, which enables fast and reliable sampling in an arrayed form, with less surface adsorption and bias for different components. The resulting device thus well supports high throughput, quantitative, and repeatable assays all by hands operation. With all these merits, multiplex analysis of ions, proteins, and microbe have all been realized on this platform, which has paved the way to level-up analysis on μPADs.

Effect of venous and lymphatic congestion on lymph capillary pressure of the skin in healthy volunteers and patients with lymph edema.

Science.gov (United States)

Gretener, S B; Läuchli, S; Leu, A J; Koppensteiner, R; Franzeck, U K

2000-01-01

The aim of the present study was to assess the influence of venous and lymphatic congestion on lymph capillary pressure (LCP) in the skin of the foot dorsum of healthy volunteers and of patients with lymph edema. LCP was measured at the foot dorsum of 12 patients with lymph edema and 18 healthy volunteers using the servo-nulling technique. Glass micropipettes (7-9 microm) were inserted under microscopic control into lymphatic microvessels visualized by fluorescence microlymphography before and during venous congestion. Venous and lymphatic congestion was attained by cuff compression (50 mm Hg) at the thigh level. Simultaneously, the capillary filtration rate was measured using strain gauge plethysmography. The mean LCP in patients with lymph edema increased significantly (p < 0.05) during congestion (15.7 +/- 8.8 mm Hg) compared to the control value (12.2 +/- 8.9 mm Hg). The corresponding values of LCP in healthy volunteers were 4.3 +/- 2.6 mm Hg during congestion and 2.6 +/- 2.8 mm Hg during control conditions (p < 0.01). The mean increase in LCP in patients with lymph edema was 3.4 +/- 4.1 mm Hg, and 1.7 +/- 2.0 mm Hg in healthy volunteers (NS). The maximum spread of the lymph capillary network in patients increased from 13.9 +/- 6.8 mm before congestion to 18.8 +/- 8.2 mm during thigh compression (p < 0.05). No increase could be observed in healthy subjects. In summary, venous and lymphatic congestion by cuff compression at the thigh level results in a significant increase in LCP in healthy volunteers as well as in patients with lymph edema. The increased spread of the contrast medium in the superficial microlymphatics in lymph edema patients indicates a compensatory mechanism for lymphatic drainage during congestion of the veins and lymph collectors of the leg. Copyright 2000 S. Karger AG, Basel

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

Science.gov (United States)

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

Practical capillary electrophoresis

CERN Document Server

Weinberger, Robert

2000-01-01

In the 1980s, capillary electrophoresis (CE) joined high-performance liquid chromatography (HPLC) as the most powerful separation technique available to analytical chemists and biochemists. Published research using CE grew from 48 papers in the year of commercial introduction (1988) to 1200 in 1997. While only a dozen major pharmaceutical and biotech companies have reduced CE to routine practice, the applications market is showing real or potential growth in key areas, particularly in the DNA marketplace for genomic mapping and forensic identification. For drug development involving small molecules (including chiral separations), one CE instrument can replace 10 liquid chromatographs in terms of speed of analysis. CE also uses aqueous rather than organic solvents and is thus environmentally friendlier than HPLC. The second edition of Practical Capillary Electrophoresis has been extensively reorganized and rewritten to reflect modern usage in the field, with an emphasis on commercially available apparatus and ...

Experimental and numerical studies of choked flow through adiabatic and diabatic capillary tubes

International Nuclear Information System (INIS)

Deodhar, Subodh D.; Kothadia, Hardik B.; Iyer, K.N.; Prabhu, S.V.

2015-01-01

Capillary tubes are extensively used in several cooling applications like refrigeration, electronic cooling etc. Local pressure variation in adiabatic straight capillary tube (mini channel) is studied experimentally and numerically with R134a as the working fluid. Experiments are performed on two straight capillary tubes. It is found that the diameter is the most sensitive design parameter of the capillary tube. Experiments are performed on five helically coiled capillary tubes to quantify the effect of pitch and curvature of helically coiled capillary tube on the pressure drop. Non dimensionalized factor to account coiling of capillary tube is derived to calculate mass flow rate in helically coiled capillary tubes. Flow visualization in adiabatic capillary tube confirms the bubbly nature of two phase flow. Numerical and experimental investigations in diabatic capillary tube suggest that the use of positive displacement pump and choking at the exit of the channel ensures flow stability. - Highlights: • Model is developed to design capillary tube in adiabatic and diabatic condition. • Effect of coil curvature on pressure drop is studied experimentally. • Correlation is developed to predict mass flow rate in helical capillary tubes. • Flow visualization is carried out to check the type of two phase flow. • Effect of choked flow on diabatic capillary tubes is studied experimentally.

Demonstration of Nautilus Centripetal Capillary Condenser Technology

Science.gov (United States)

Wheeler, RIchard; Tang, Linh; Wambolt, Spencer; Golliher, Eric; Agui, Juan

2016-01-01

This paper describes the results of a proof of concept effort for development of a Nautilus Centripetal Capillary Condenser (NCCC or NC3) used for microgravity compatible water recovery from moist air with integral passive phase separation. Removal of liquid condensate from the air stream exiting a condenser is readily performed here on Earth. In order to perform this function in space however, without gravity or mechanical action, other tactics including utilization of inertial, drag and capillary forces are required. Within the NC3, liquid water forms via condensation on cold condenser surfaces as humid air passes along multiple spiral channels, each in its own plane, all together forming a stacked plate assembly. Non-mechanical inertial forces are employed to transfer condensate, as it forms, via centripetal action to the outer perimeter of each channel. A V-shaped groove, constructed on this outer edge of the spiral channel, increases local capillary forces thereby retaining the liquid. Air drag then pulls the liquid along to a collection region near the center of the device. Dry air produced by each parallel spiral channel is combined in a common orthogonal, out-of-plane conduit passing down the axial center of the stacked device. Similarly, the parallel condensate streams are combined and removed from the condenser/separator through yet another out-of-plane axial conduit. NC3 is an integration of conventional finned condenser operation, combined with static phase separation and capillary transport phenomena. A Mars' transit mission would be a logical application for this technology where gravity is absent and the use of vibrating, energy-intensive, motor-driven centrifugal separators is undesired. Here a vapor stream from either the Heat Melt Compactor or the Carbon dioxide Reduction Assembly, for example, would be dried to a dew point of 10 deg using a passive NC3 condenser/separator with the precious water condensate recycled to the water bus.

CAPILLARY NETWORK ALTERATIONS IN X-LINKED RETINOSCHISIS IMAGED ON OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY.

Science.gov (United States)

Romano, Francesco; Arrigo, Alessandro; Chʼng, Soon Wai; Battaglia Parodi, Maurizio; Manitto, Maria Pia; Martina, Elisabetta; Bandello, Francesco; Stanga, Paulo E

2018-06-05

To assess foveal and parafoveal vasculature at the superficial capillary plexus, deep capillary plexus, and choriocapillaris of patients with X-linked retinoschisis by means of optical coherence tomography angiography. Six patients with X-linked retinoschisis (12 eyes) and seven healthy controls (14 eyes) were recruited and underwent complete ophthalmologic examination, including best-corrected visual acuity, dilated fundoscopy, and 3 × 3-mm optical coherence tomography angiography macular scans (DRI OCT Triton; Topcon Corp). After segmentation and quality review, optical coherence tomography angiography slabs were imported into ImageJ 1.50 (NIH; Bethesda) and digitally binarized. Quantification of vessel density was performed after foveal avascular zone area measurement and exclusion. Patients were additionally divided into "responders" and "nonresponders" to dorzolamide therapy. Foveal avascular zone area resulted markedly enlarged at the deep capillary plexus (P < 0.001), particularly in nonresponders. Moreover, patients disclosed a significant deep capillary plexus rarefaction, when compared with controls (P: 0.04); however, a subanalysis revealed that this damage was limited to the fovea (P: 0.006). Finally, the enlargement of foveal avascular zone area positively correlated with a decline in best-corrected visual acuity (P: 0.01). Prominent foveal vascular impairment is detectable in the deep capillary plexus of patients with X-linked retinoschisis. Our results correlate with functional outcomes, suggesting a possible vascular role in X-linked retinoschisis clinical manifestations.

Ion guiding in macro-size insulating capillaries: straight, tapered, and curved shapes

Science.gov (United States)

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.

Ionization Waves in a Fast, Hollow-Cathode-Assisted Capillary Discharge

International Nuclear Information System (INIS)

Rutkevich, I.; Mond, M.; Kaufman, Y.; Choi, P.; Favre, M.

1999-01-01

The initial, low-current stage of the evolution of a soft x-ray emitting, hollow-cathode-assisted capillary discharge initiated by a steep high-voltage pulse is investigated. The capillary is surrounded by a shield having the cathode potential. The mean electric field E of the order of 10 kV/cm and the low gas pressure (P<1Torr) provide conditions for extensive electron runaway. This is taken into account in the formulation of the theoretical approach by retaining the inertial terms in the momentum equation for the electrons. In addition, the ionization rate is calculated by considering the cross section for ionization by high-energy electrons. The two-dimensional system of the basic equations is reduced to a system of one-dimensional equations for the axial distributions of the physical quantities by introducing appropriate radial profiles of the electric potential, and the electron gas parameters and satisfying the electrodynamic boundary conditions at the capillary wall and at the shield. The resulting system of equations admits solutions in the form of stationary ionization waves transferring the anode potential to the cathode end. Numerical calculations of such solutions for argon show that the wave velocity V increases with the gas pressure P and with the density of initial electron beam ejected from the cathode hole ahead of the ionization front, while the dependence of V on the applied voltage is weak. At the instant when the virtual anode reaches the cathode hole, the plasma in the capillary is not yet fully ionized. The traverse time of the ionization wave along the capillary calculated for various gas pressures is in reasonable agreement with experimentally registered time delay for a high-current stage resulting in voltage collapse and soft x-ray emission

Capillary force between wetted nanometric contacts and its application to atomic force microscopy.

Science.gov (United States)

Crassous, Jérôme; Ciccotti, Matteo; Charlaix, Elisabeth

2011-04-05

We extend to the case of perfect wetting the exact calculation of Orr et al. (J. Fluid. Mech. 1975, 67, 723) for a pendular ring connecting two dry surfaces. We derive an approximate analytical expression for the capillary force between two highly curved surfaces covered by a wetting liquid film. The domain of validity of this expression is assessed and extended by a custom-made numerical simulation based on the full exact mathematical description. In the case of attractive liquid-solid van der Waals interactions, the capillary force increases monotonically with decreasing vapor pressure up to several times its saturation value. This accurate description of the capillary force makes it possible to estimate the adhesion force between wet nanoparticles; it can also be used to quantitatively interpret pull-off forces measured by atomic force microscopy.

New Liquid Phases for the Gas Chromatographic Separation of Strong Bases on Capillary Columns

OpenAIRE

Grob, K.

2017-01-01

The current practice of pretreating the solid support with free alkali to increase separation efficiency for basic compounds proved to be unsuitable for capillary columns. Instead of this, homogenous organic materials of high base strength are required. We found polyethylene imine (PEI) and polypropylene imine (PPI) to be very efficient as liquid phases of capillary columns for the separation of bases. The preparation of polymers is mentioned. Silanization or acetylation of the free hydroxyl ...

First report of microcephaly-capillary malformations syndrome in ...

African Journals Online (AJOL)

Background: Microcephaly-capillary malformation (MIC-CAP) syndrome is a newly described autosomal recessive syndrome characterized by microcephaly, multiple cutaneous capillary malformations, intractable epilepsy and profound developmental delay. We present the first description of MIC-CAP syndrome in Russia.

Electrical Stimulation of Denervated Rat Skeletal Muscle Retards Capillary and Muscle Loss in Early Stages of Disuse Atrophy

Directory of Open Access Journals (Sweden)

Kouki Nakagawa

2017-01-01

Full Text Available The purpose of the present study is to investigate the effects of low-frequency electrical muscle stimulation (ES on the decrease in muscle mass, fiber size, capillary supply, and matrix metalloproteinase (MMP immunoreactivity in the early stages of denervation-induced limb disuse. Direct ES was performed on the tibialis anterior muscle following denervation in seven-week-old male rats. The rats were divided into the following groups: control (CON, denervation (DN, and denervation with direct ES (DN + ES. Direct ES was performed at an intensity of 16 mA and a frequency of 10 Hz for 30 min per day, six days a week, for one week. We performed immunohistochemical staining to determine the expression of dystrophin, CD34, and MMP-2 in transverse sections of TA muscles. The weight, myofiber cross-sectional area (FCSA, and capillary-to-fiber (C/F ratio of the tibialis anterior (TA muscle were significantly reduced in the DN group compared to the control and DN + ES groups. The MMP-2 positive area was significantly greater in DN and DN + ES groups compared to the control group. These findings suggest beneficial effects of direct ES in reducing muscle atrophy and capillary regression without increasing MMP-2 immunoreactivity in the early stages of DN-induced muscle disuse in rat hind limbs.

Electrical Stimulation of Denervated Rat Skeletal Muscle Retards Capillary and Muscle Loss in Early Stages of Disuse Atrophy

Science.gov (United States)

Nakagawa, Kouki; Hayao, Keishi; Yotani, Kengo; Ogita, Futoshi; Yamamoto, Noriaki; Onishi, Hideaki

2017-01-01

The purpose of the present study is to investigate the effects of low-frequency electrical muscle stimulation (ES) on the decrease in muscle mass, fiber size, capillary supply, and matrix metalloproteinase (MMP) immunoreactivity in the early stages of denervation-induced limb disuse. Direct ES was performed on the tibialis anterior muscle following denervation in seven-week-old male rats. The rats were divided into the following groups: control (CON), denervation (DN), and denervation with direct ES (DN + ES). Direct ES was performed at an intensity of 16 mA and a frequency of 10 Hz for 30 min per day, six days a week, for one week. We performed immunohistochemical staining to determine the expression of dystrophin, CD34, and MMP-2 in transverse sections of TA muscles. The weight, myofiber cross-sectional area (FCSA), and capillary-to-fiber (C/F) ratio of the tibialis anterior (TA) muscle were significantly reduced in the DN group compared to the control and DN + ES groups. The MMP-2 positive area was significantly greater in DN and DN + ES groups compared to the control group. These findings suggest beneficial effects of direct ES in reducing muscle atrophy and capillary regression without increasing MMP-2 immunoreactivity in the early stages of DN-induced muscle disuse in rat hind limbs. PMID:28497057

Imbibition of ``Open Capillary'': Fundamentals and Applications

Science.gov (United States)

Tani, Marie; Kawano, Ryuji; Kamiya, Koki; Okumura, Ko

2015-11-01

Control or transportation of small amount of liquid is one of the most important issues in various contexts including medical sciences or pharmaceutical industries to fuel delivery. We studied imbibition of ``open capillary'' both experimentally and theoretically, and found simple scaling laws for both statics and dynamics of the imbibition, similarly as that of imbibition of capillary tubes. Furthermore, we revealed the existence of ``precursor film,'' which developed ahead of the imbibing front, and the dynamics of it is described well by another scaling law for capillary rise in a corner. Then, to show capabilities of open capillaries, we demonstrated two experiments by fabricating micro mixing devices to achieve (1) simultaneous multi-color change of the Bromothymol blue (BTB) solution and (2) expression of the green florescent protein (GFP). This research was partly supported by ImPACT Program of Council for Science, Technology and Innovation (Cabinet Office, Government of Japan). M. T. is supported by the Japan Society for the Promotion of Science Research Fellowships for Young Scientists.

Capillary pericytes regulate cerebral blood flow in health and disease

DEFF Research Database (Denmark)

Hall, Catherine N; Reynell, Clare; Gesslein, Bodil

2014-01-01

Increases in brain blood flow, evoked by neuronal activity, power neural computation and form the basis of BOLD (blood-oxygen-level-dependent) functional imaging. Whether blood flow is controlled solely by arteriole smooth muscle, or also by capillary pericytes, is controversial. We demonstrate t...

Influence of the inner diameters of capillary on the Z-Pinch plasma of the capillary discharge soft X-ray laser

International Nuclear Information System (INIS)

Jiang, Shan; Zhao, Yong-peng; Cui, Huai-yu; Li, Lian-bo; Ding, Yu-jie; Zhang, Wen-hong; Li, Wei

2015-01-01

In this paper, the effects of inner diameters on the Z-pinch plasma of capillary discharge soft X-ray laser were investigated with the 3.2 mm and 4.0 mm inner diameter alumina capillaries. The intensities of the laser emitted from the 3.2 mm and 4.0 mm inner diameter alumina capillaries were measured under different initial pressures. To understand the underlying physics of the experimental measurements, the Z-pinch plasma simulations had been conducted with a one-dimensional cylindrical symmetry Lagrangian magneto-hydrodynamics (MHD) code. The parametric studies of Z-pinch plasma, such as the electron temperature, the electron density and the Ne-like Ar ion density, were performed with the MHD code. With the experimental and the simulated results, the discussions had been conducted on the Z-pinch plasma of Ne-like Ar 46.9 nm laser with the 3.2 mm and 4.0 mm inner diameter alumina capillaries. The analysis had been made on the difference of the gain coefficients under the optimum pressures with both capillaries. Then, the effects of inner diameters on the optimum pressure and the pressure domain were analyzed. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Recent advances of capillary electrophoresis in pharmaceutical analysis.

Science.gov (United States)

Suntornsuk, Leena

2010-09-01

This review covers recent advances of capillary electrophoresis (CE) in pharmaceutical analysis. The principle, instrumentation, and conventional modes of CE are briefly discussed. Advances in the different CE techniques (non-aqueous CE, microemulsion electrokinetic chromatography, capillary isotachophoresis, capillary electrochromatography, and immunoaffinity CE), detection techniques (mass spectrometry, light-emitting diode, fluorescence, chemiluminescence, and contactless conductivity), on-line sample pretreatment (flow injection) and chiral separation are described. Applications of CE to assay of active pharmaceutical ingredients (APIs), drug impurity testing, chiral drug separation, and determination of APIs in biological fluids published from 2008 to 2009 are tabulated.

Influence of ignored and well-known zone distortions on the separation performance of proteins in capillary free zone electrophoresis with special reference to analysis in polyacrylamide-coated fused silica capillaries in various buffers. II. Experimental studies at acidic pH with on-line enrichment.

Science.gov (United States)

Mohabbati, Sheila; Hjertén, Stellan; Westerlund, Douglas

2004-10-22

The separation of acidic and basic model proteins was studied in capillary free zone electrophoresis in a polyacrylamide-coated, electroosmosis-free capillary at pH below their isoelectric points (pI) using various buffers at pH 2.7-4.8 with UV detection at 200 nm. The separation performance was significantly dependent on the coating quality, which may even differ within the same batch of capillaries. In addition, a washing step with 2 M HCl and the storage of the capillary in distilled water was essential for the performance. For high efficiency and resolution the choice of buffer constituents was extremely important which is discussed in quantitative terms in Part I. The most promising buffers were ammonium acetate and ammonium hydroxyacetate at pH 4 (ionic strengths: 0.12 and 0.15 M, respectively) with plate numbers up to 1,700,000 plates/m, corresponding to a zone width (2sigma) of only 1 mm in a capillary with 40 cm effective length, when the injected samples were dissolved in a 10-fold diluted background electrolyte (BGE), a zone even narrower than those obtained in polyacrylamide gel electrophoresis, the characteristic feature of which is remarkably thin zones. In the experiment giving this plate number, the calculated variance for longitudinal diffusion was larger than all the other calculated variances (those for the width of the starting zone, Joule heating, sedimentation and the curvature of the capillary). Interestingly, the effect of capillary curvature was significant. In addition, the sum of all other imaginable variances (corresponding to various types of slow on/off kinetics and hyper-sharp peaks) was in the most successful experiments only 28-50% of the variance for longitudinal diffusion. One hundred- to two hundred-fold dilution of the BGE improved the detection limits and provided high precision in both migration times and peak areas with ammonium hydroxyacetate and ammonium acetate as background electrolytes. However, that high dilution

A coupling modulation model of capillary waves from gravity waves: Theoretical analysis and experimental validation

Science.gov (United States)

Chen, Pengzhen; Wang, Xiaoqing; Liu, Li; Chong, Jinsong

2016-06-01

According to Bragg theory, capillary waves are the predominant scatterers of high-frequency band (such as Ka-band) microwave radiation from the surface of the ocean. Therefore, understanding the modulation mechanism of capillary waves is an important foundation for interpreting high-frequency microwave remote sensing images of the surface of the sea. In our experiments, we discovered that modulations of capillary waves are significantly larger than the values predicted by the classical theory. Further, analysis shows that the difference in restoring force results in an inflection point while the phase velocity changes from gravity waves region to capillary waves region, and this results in the capillary waves being able to resonate with gravity waves when the phase velocity of the gravity waves is equal to the group velocity of the capillary waves. Consequently, we propose a coupling modulation model in which the current modulates the capillary wave indirectly by modulating the resonant gravity waves, and the modulation of the former is approximated by that of the latter. This model very effectively explains the results discovered in our experiments. Further, based on Bragg scattering theory and this coupling modulation model, we simulate the modulation of normalized radar cross section (NRCS) of typical internal waves and show that the high-frequency bands are superior to the low-frequency bands because of their greater modulation of NRCS and better radiometric resolution. This result provides new support for choice of radar band for observation of wave-current modulation oceanic phenomena such as internal waves, fronts, and shears.

Transmission of fast highly charged ions through straight and tapered glass capillaries

International Nuclear Information System (INIS)

Ayyad, Asma M; Keerthisinghe, D; Kayani, A; Tanis, J A; Dassanayake, B S; Ikeda, T

2013-01-01

The transmission of 1 and 3 MeV protons through a borosilicate straight glass capillary and a tapered glass capillary was investigated. The straight capillary had a diameter of ∼0.18 mm and a length of ∼14.4 mm, while the tapered capillary had an inlet diameter of ∼0.71 mm, an outlet diameter of ∼0.10 mm and a length of ∼28 mm. The results show that the 1 and 3 MeV protons traverse through both samples without energy loss, while the tapered capillary showed better transmission than the straight capillary. (paper)

Capillary growth, ultrastructure remodeling and exercise training in skeletal muscle of essential hypertensive patients

DEFF Research Database (Denmark)

Gliemann, Lasse; Buess, Rahel; Nyberg, Michael Permin

2015-01-01

obtained from m. vastus lateralis in essential hypertensive patients (n=10) and normotensive controls (n=11) before and after 8 weeks of aerobic exercise training. Morphometry was performed after transmission electron microscopy and protein levels of several angioregulatory factors were determined. RESULTS......AIM: The aim was to elucidate whether essential hypertension is associated with altered capillary morphology and density and to what extend exercise training can normalize these parameters. METHODS: To investigate angiogenesis and capillary morphology in essential hypertension, muscle biopsies were...... of vascular endothelial growth factor (VEGF), VEGF receptor-2 and thrombospondin-1 were similar in normo- and hypertensive subjects but tissue inhibitor of matrix metalloproteinase was 69% lower in the hypertensive group. After training, angiogenesis was evident by 15% increased capillary-to-fiber ratio...

The formation of metallic plasmas in transient capillary discharges at high current

International Nuclear Information System (INIS)

Wyndham, E S; Favre, M; Aliaga-Rossel, R

2006-01-01

We report observations of the formation of a metallic plasma in a high aspect ratio z-pinch confined within a ceramic capillary. A series of experiments on different capillary geometries was undertaken in which titanium metal rings were used to promote the formation of a titanium plasma through preferential ablation. In an initial vacuum a titanium seed plasma is formed in the hollow cathode (HC) volume by a low energy laser spark. This pre-ionizing plasma is assisted in its expansion into the z-pinch volume by the electron beams generated by a pre-ionizing discharge in the capillary, due to the HC effect. Further intense e-beam activity occurs on applying the main driver current to the capillary electrodes before the discharge impedance abruptly drops to give rise to an ensuing high current z-pinch. A segmented titanium ring structure within the capillary promotes metal ablation. The discharges are performed in tubes of 60 to 110 mm length and 3 and 5 mm effective internal diameter. The main discharge current is provided from a small pulsed power switched coaxial line, at up to 150 kA. The generator may be configured to deliver two different rates of current rise and this is found to have a significant effect on the plasma dynamics. The plasma properties are obtained from observations of the axial x-ray emission. The diagnostics used are filtered Si diodes, filtered time-resolved multi-pinhole camera images and the time resolved soft x-ray spectrum from 3 to 20 nm. While a single species metal plasma is not obtained, a very significant proportion of Ti is achieved in the higher rate of current rise configuration. The fraction of Ti diminishes for the longest length discharges and for the larger diameter tube diameter, as does the observed z-pinch uniformity. There is a weak dependance of the electron temperature with tube geometry, but the plasma density falls substantially in the longer discharges. This coincides with diminished effectiveness of the transient HC

Evaluation of microvascular endothelial function and capillary density in patients with infective endocarditis using laser speckle contrast imaging and video-capillaroscopy.

Science.gov (United States)

Barcelos, Amanda; Tibirica, Eduardo; Lamas, Cristiane

2018-07-01

To evaluate the systemic microcirculation of patients with infective endocarditis (IE). This is a comparative study of patients with definite IE by the modified Duke criteria admitted to our center for treatment. A reference group of sex- and age-matched healthy volunteers was included. Microvascular flow was evaluated in the forearm using a laser speckle contrast imaging system, for noninvasive measurement of cutaneous microvascular perfusion, in combination with skin iontophoresis of acetylcholine (ACh) and sodium nitroprusside (SNP) to test microvascular reactivity. Microvascular density was evaluated using skin video-capillaroscopy. We studied 22 patients with IE; 15 were male and seven female. The mean age and standard deviation (SD) were 45.5 ± 17.3 years. Basal skin microvascular conductance was significantly increased in patients with IE, compared with healthy individuals (0.36 ± 0.13 versus 0.21 ± 0.08 APU/mmHg; P < 0.0001). The increase in microvascular conductance induced by ACh in patients was 0.21 ± 0.17 and in the reference group, it was 0.37 ± 0.14 APU/mmHg (P = 0.0012). The increase in microvascular conductance induced by SNP in patients was 0.18 ± 0.14 and it was 0.29 ± 0.15 APU/mmHg (P = 0.0140) in the reference group. The basal mean skin capillary density of patients (135 ± 24 capillaries/mm 2 ) was significantly higher, compared with controls (97 ± 21 capillaries/mm 2 ; P < 0.0001). The main findings in the microcirculation of patients with IE were greater basal vasodilation and a reduction of the endothelium-dependent and -independent microvascular reactivity, as well as greater functional skin capillary density compared to healthy individuals. Copyright © 2018 Elsevier Inc. All rights reserved.

Effect of capillary condensation on gas transport properties in porous media

Science.gov (United States)

Yoshimoto, Yuta; Hori, Takuma; Kinefuchi, Ikuya; Takagi, Shu

2017-10-01

We investigate the effect of capillary condensation on gas diffusivity in porous media composed of randomly packed spheres with moderate wettability. To simulate capillary phenomena at the pore scale while retaining complex pore networks of the porous media, we employ density functional theory (DFT) for coarse-grained lattice gas models. The lattice DFT simulations reveal that capillary condensations preferentially occur at confined pores surrounded by solid walls, leading to the occlusion of narrow pores. Consequently, the characteristic lengths of the partially wet structures are larger than those of the corresponding dry structures with the same porosities. Subsequent gas diffusion simulations exploiting the mean-square displacement method indicate that while the effective diffusion coefficients significantly decrease in the presence of partially condensed liquids, they are larger than those in the dry structures with the same porosities. Moreover, we find that the ratio of the porosity to the tortuosity factor, which is a crucial parameter that determines an effective diffusion coefficient, can be reasonably related to the porosity even for the partially wet porous media.

Design and evaluation of capillary coupled with optical fiber light-emitting diode induced fluorescence detection for capillary electrophoresis.

Science.gov (United States)

Ji, Hongyun; Li, Meng; Guo, Lihong; Yuan, Hongyan; Wang, Chunling; Xiao, Dan

2013-09-01

A new detector, capillary coupled with optical fiber LED-induced fluorescence detector (CCOF-LED-IFD, using CCOF for short), is introduced for CE. The strategy of the present work was that the optical fiber and separation capillary were, in the parallel direction, fastened in a fixation capillary with larger inner diameter. By employing larger inner diameter, the fixation capillary allowed the large diameter of the optical fiber to be inserted into it. By transmitting an enhanced excitation light through the optical fiber, the detection sensitivity was improved. The advantages of the CCOF-CE system were validated by the detection of riboflavin, and the results were compared to those obtained by the in-capillary common optical fiber LED-induced fluorescence detector (IC-COF-LED-IFD, using COF for short). The LODs of CCOF-CE and COF-CE were 0.29 nM and 11.0 nM (S/N = 3), respectively. The intraday (n = 6) repeatability and interday (n = 6) reproducibility of migration time and corresponding peak area for both types of CE were all less than 1.10 and 3.30%, respectively. The accuracy of the proposed method was judged by employing standard addition method, and recoveries obtained were in the range of 98.0-102.4%. The results indicated that the sensitivity of the proposed system was largely improved, and that its reproducibility and accuracy were satisfactory. The proposed system was successfully applied to separate and determine riboflavin in real sample. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Vulvar Lobular Capillary Hemangioma (Pyogenic Granuloma

Directory of Open Access Journals (Sweden)

Kian-Mei Chong

2005-03-01

Conclusion: Pyogenic granuloma is considered a reactive hyperproliferative vascular response to trauma or other stimuli. The name “pyogenic granuloma” is a misnomer since the condition is not associated with pus and does not represent a granuloma histologically. There are a few cases of lobular capillary hemangioma of the glans penis but it is rare on the female genitalia. We present this case to help physicians become aware that lobular capillary hemangiomas may occur at this site.

Vascular permeability-increasing effect of the leaf essential oil of ...

African Journals Online (AJOL)

African Journal of Traditional, Complementary and Alternative Medicines ... Analysis of the differences in vascular permeability between treatment groups showed that, Ocimum oil, in intensity and duration, was significantly (p < 0.05) more effective in increasing cutaneous capillary permeability over a 24h period after ...

Dynamic /sup 99m/Tc-DTPA radioaerosol lung scanning for the evaluation of alveolar-capillary barrier permeability

Energy Technology Data Exchange (ETDEWEB)

Maini, C L; Marchetti, L; Bonetti, M G; Giordano, A; Pistelli, R; Antonelli Incalzi, R

1987-01-01

Pulmonary clearance of small droplet /sup 99m/Tc-DTPA radioaerosol was studied in 100 patients (12 normal subjects, N; 10 asymptomatic healthy smoker, FA; 31 patients with interstitial lung diseases, IP; 47 patients with chronic obstructive lung disease, BPCO). The first seven minutes of clearance were described with the function At=Ao*exp(-K*t) and the time constant K was considered representative of the /sup 99m/Tc-DTPA clearance rate and hence of the alveolar-capillary barrier permeability. Groups FA, IP and BPCO showed a significant (p<0.05) or a highly significant (p<0.01) increase in permeability when compared to group N. No correlation was found between permeability and bronchial obstraction tests. The following conclusions were drawn: 1) /sup 99m/Tc-DTPA dynamic lung scanning is an easy, non-invasive method to assess derangements of alveolar-capillary barrier permeability secondary to epithelial damage; 2) permeability increase is a very early effect of cigarette smoke damafe to the epithelium; 3) other mechanisms of epithelial injury are present in diffuse lung disease; 4) while the clinical role of this new pathophysiological test is not yet clear, it is likely that it may become a very early marker of pulmonary epithelial damage in diffuse lung disease. 35 refs.

Hysteretic capillary condensation of 4He on Nuclepore substrates

International Nuclear Information System (INIS)

Godshalk, K.M.; Smith, D.T.; Hallock, R.B.

1987-01-01

Measurements of the approach to capillary condensation and the hysteresis encountered in capillary condensation are reported for helium adsorbed on the polycarbonate substrate Nuclepore. (Author) (5 refs., 3 figs.)

Density functional study of condensation in capped capillaries.

Science.gov (United States)

Yatsyshin, P; Savva, N; Kalliadasis, S

2015-07-15

We study liquid adsorption in narrow rectangular capped capillaries formed by capping two parallel planar walls (a slit pore) with a third wall orthogonal to the two planar walls. The most important transition in confined fluids is arguably condensation, where the pore becomes filled with the liquid phase which is metastable in the bulk. Depending on the temperature T, the condensation in capped capillaries can be first-order (at T≤Tcw) or continuous (at T>Tcw), where Tcw is the capillary wetting temperature. At T>Tcw, the capping wall can adsorb mesoscopic amounts of metastable under-condensed liquid. The onset of condensation is then manifested by the continuous unbinding of the interface between the liquid adsorbed on the capping wall and the gas filling the rest of the capillary volume. In wide capped capillaries there may be a remnant of wedge filling transition, which is manifested by the adsorption of liquid drops in the corners. Our classical statistical mechanical treatment predicts a possibility of three-phase coexistence between gas, corner drops and liquid slabs adsorbed on the capping wall. In sufficiently wide capillaries we find that thick prewetting films of finite length may be nucleated at the capping wall below the boundary of the prewetting transition. Prewetting then proceeds in a continuous manner manifested by the unbinding interface between the thick and thin films adsorbed on the side walls. Our analysis is based on a detailed numerical investigation of the density functional theory for the fluid equilibria for a number of illustrative case studies.

Principles of Micellar Electrokinetic Capillary Chromatography Applied in Pharmaceutical Analysis

Directory of Open Access Journals (Sweden)

Árpád Gyéresi

2013-02-01

Full Text Available Since its introduction capillary electrophoresis has shown great potential in areas where electrophoretic techniques have rarely been used before, including here the analysis of pharmaceutical substances. The large majority of pharmaceutical substances are neutral from electrophoretic point of view, consequently separations by the classic capillary zone electrophoresis; where separation is based on the differences between the own electrophoretic mobilities of the analytes; are hard to achieve. Micellar electrokinetic capillary chromatography, a hybrid method that combines chromatographic and electrophoretic separation principles, extends the applicability of capillary electrophoretic methods to neutral analytes. In micellar electrokinetic capillary chromatography, surfactants are added to the buffer solution in concentration above their critical micellar concentrations, consequently micelles are formed; micelles that undergo electrophoretic migration like any other charged particle. The separation is based on the differential partitioning of an analyte between the two-phase system: the mobile aqueous phase and micellar pseudostationary phase. The present paper aims to summarize the basic aspects regarding separation principles and practical applications of micellar electrokinetic capillary chromatography, with particular attention to those relevant in pharmaceutical analysis.

Recent applications of nanomaterials in capillary electrophoresis.

Science.gov (United States)

González-Curbelo, Miguel Ángel; Varela-Martínez, Diana Angélica; Socas-Rodríguez, Bárbara; Hernández-Borges, Javier

2017-10-01

Nanomaterials have found an important place in Analytical Chemistry and, in particular, in Separation Science. Among them, metal-organic frameworks, magnetic and non-magnetic nanoparticles, carbon nanotubes and graphene, as well as their combinations, are the most important nanomaterials that have been used up to now. Concerning capillary electromigration techniques, these nanomaterials have also been used as both pseudostationary phases in electrokinetic chromatography (EKC) and as stationary phases in microchip capillary electrophoresis (CE) and capillary electrochromatography (CEC), as a result of their interesting and particular properties. This review article pretends to provide a general and critical revision of the most recent applications of nanomaterials in this field (period 2010-2017). © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Targeted Functionalization of Nanoparticle Thin Films via Capillary Condensation

KAUST Repository

Gemici, Zekeriyya; Schwachulla, Patrick I.; Williamson, Erik H.; Rubner, Michael F.; Cohen, Robert E.

2009-01-01

Capillary condensation, an often undesired natural phenomenon in nanoporous materials, was used advantageously as a universal functionalization strategy in nanoparticle thin films assembled layer-by-layer. Judicious choice of nanoparticle (and therefore pore) size allowed targeted capillary condensation of chemical vapors of both hydrophilic and hydrophobic molecules across film thickness. Heterostructured thin films with modulated refractive index profiles produced in this manner exhibited broadband antireflection properties with an average reflectance over the visible region of the spectrum of only 0.4%. Capillary condensation was also used to modify surface chemistry and surface energy. Photosensitive capillary-condensates were UV-cross-linked in situ. Undesired adventitious condensation of humidity could be avoided by condensation of hydrophobic materials such as poly(dimethyl siloxane). © 2009 American Chemical Society.

Targeted Functionalization of Nanoparticle Thin Films via Capillary Condensation

KAUST Repository

Gemici, Zekeriyya

2009-03-11

Capillary condensation, an often undesired natural phenomenon in nanoporous materials, was used advantageously as a universal functionalization strategy in nanoparticle thin films assembled layer-by-layer. Judicious choice of nanoparticle (and therefore pore) size allowed targeted capillary condensation of chemical vapors of both hydrophilic and hydrophobic molecules across film thickness. Heterostructured thin films with modulated refractive index profiles produced in this manner exhibited broadband antireflection properties with an average reflectance over the visible region of the spectrum of only 0.4%. Capillary condensation was also used to modify surface chemistry and surface energy. Photosensitive capillary-condensates were UV-cross-linked in situ. Undesired adventitious condensation of humidity could be avoided by condensation of hydrophobic materials such as poly(dimethyl siloxane). © 2009 American Chemical Society.

Targeted functionalization of nanoparticle thin films via capillary condensation.

Science.gov (United States)

Gemici, Zekeriyya; Schwachulla, Patrick I; Williamson, Erik H; Rubner, Michael F; Cohen, Robert E

2009-03-01

Capillary condensation, an often undesired natural phenomenon in nanoporous materials, was used advantageously as a universal functionalization strategy in nanoparticle thin films assembled layer-by-layer. Judicious choice of nanoparticle (and therefore pore) size allowed targeted capillary condensation of chemical vapors of both hydrophilic and hydrophobic molecules across film thickness. Heterostructured thin films with modulated refractive index profiles produced in this manner exhibited broadband antireflection properties with an average reflectance over the visible region of the spectrum of only 0.4%. Capillary condensation was also used to modify surface chemistry and surface energy. Photosensitive capillary-condensates were UV-cross-linked in situ. Undesired adventitious condensation of humidity could be avoided by condensation of hydrophobic materials such as poly(dimethyl siloxane).

Characterization and Study of Transgenic Cultivars by Capillary and Microchip Electrophoresis

Directory of Open Access Journals (Sweden)

Elena Domínguez Vega

2014-12-01

Full Text Available Advances in biotechnology have increased the demand for suitable analytical techniques for the analysis of genetically modified organisms. Study of the substantial equivalence, discrimination between transgenic and non-transgenic cultivars, study of the unintended effects caused by a genetic modification or their response to diverse situations or stress conditions (e.g., environmental, climatic, infections are some of the concerns that need to be addressed. Capillary electrophoresis (CE is emerging as an alternative to conventional techniques for the study and characterization of genetically modified organisms. This article reviews the most recent applications of CE for the analysis and characterization of transgenic cultivars in the last five years. Different strategies have been described depending on the level analyzed (DNA, proteins or metabolites. Capillary gel electrophoresis (CGE has shown to be particularly useful for the analysis of DNA fragments amplified by PCR. Metabolites and proteins have been mainly separated using capillary zone electrophoresis (CZE using UV and MS detection. Electrophoretic chips have also proven their ability in the analysis of transgenic cultivars and a section describing the new applications is also included.

Time-resolved observation of thermally activated rupture of a capillary-condensed water nanobridge

International Nuclear Information System (INIS)

Bak, Wan; Sung, Baekman; Kim, Jongwoo; Kwon, Soyoung; Kim, Bongsu; Jhe, Wonho

2015-01-01

The capillary-condensed liquid bridge is one of the most ubiquitous forms of liquid in nature and contributes significantly to adhesion and friction of biological molecules as well as microscopic objects. Despite its important role in nanoscience and technology, the rupture process of the bridge is not well understood and needs more experimental works. Here, we report real-time observation of rupture of a capillary-condensed water nanobridge in ambient condition. During slow and stepwise stretch of the nanobridge, we measured the activation time for rupture, or the latency time required for the bridge breakup. By statistical analysis of the time-resolved distribution of activation time, we show that rupture is a thermally activated stochastic process and follows the Poisson statistics. In particular, from the Arrhenius law that the rupture rate satisfies, we estimate the position-dependent activation energies for the capillary-bridge rupture

Pulmonary arterial pressure and right ventricular dilatation independently determine tricuspid valve insufficiency severity in pre-capillary pulmonary hypertension.

Science.gov (United States)

De Meester, Pieter; Van De Bruaene, Alexander; Delcroix, Marion; Belmans, Ann; Herijgers, Paul; Voigt, Jens-Uwe; Budts, Werner

2012-11-01

Elevated pulmonary artery systolic pressure (PASP) causes functional tricuspid valve insufficiency (TI). However, the differential contribution of pressure load and right ventricular (RV) dilatation is not well established. The study aim was to evaluate both variables in relation to TI. A cross-sectional study was performed of consecutive transthoracic echocardiographic studies of patients with pre-capillary pulmonary hypertension (PH). Both, demographic data and echocardiographic RV parameters were reviewed. TI was graded semi-quantitatively with color Doppler flow imaging. Trend analyses for TI severity (TI grade 0/4, 1/4, 2/4, 3/4, or 4/4) were performed. A proportional odds logistic regression analysis was carried out to identify independent predictors of TI severity. Eighty-one patients (56 females, 25 males; mean age 60 +/- 15 years) with pre-capillary PH were evaluated. Patients with more severe TI had a significantly lower body mass index, a lower mean systemic blood pressure, a shorter pulmonary acceleration time, a higher tricuspid regurgitant gradient, and a more dilated right ventricle. From the echocardiographic parameters, RV dilatation (p = 0.0143) and the tricuspid regurgitant gradient (p = 0.0026) were independently related to the degree of TI. In patients with pre-capillary PH, PASP and RV dilatation were both related to the increasing severity of TI. When focusing on TI to improve the prognosis of patients with pre-capillary PH, both PASP and RV dimensions should be taken into consideration.

A submicron synchrotron X-ray beam generated by capillary optics

International Nuclear Information System (INIS)

Engstroem, P.; Larsson, S.; Rindby, A.; Buttkewitz, A.; Garbe, S.; Gaul, G.; Knoechel, A.; Lechtenberg, F.; Deutsches Elektronen-Synchrotron

1991-01-01

A novel capillary optics technique for focusing synchrotron X-ray beams has been applied in an experiment performed at the DORIS storage ring at HASYLAB. This new technqiue, which utilizes the total reflection properties of X-rays inside small capillaries, has recently been applied to generate microbeams of X-rays, with a beam size down to about 10 μm using conventional X-ray tubes. The result from our recent experiment shows that capillary optics can also be used to generate a submicron beam of X-rays from a synchrotron light source. A description of the capillary unit, and the alignment procedure is given. The influence of the thermal load on the device caused by the intense flux of synchrotron radiation will be discussed. Future perspectives of the capillary techniques as applied to synchrotron radiation will be discussed. (orig.)

Hardening of particle/oil/water suspensions due to capillary bridges: Experimental yield stress and theoretical interpretation.

Science.gov (United States)

Danov, Krassimir D; Georgiev, Mihail T; Kralchevsky, Peter A; Radulova, Gergana M; Gurkov, Theodor D; Stoyanov, Simeon D; Pelan, Eddie G

2018-01-01

Suspensions of colloid particles possess the remarkable property to solidify upon the addition of minimal amount of a second liquid that preferentially wets the particles. The hardening is due to the formation of capillary bridges (pendular rings), which connect the particles. Here, we review works on the mechanical properties of such suspensions and related works on the capillary-bridge force, and present new rheological data for the weakly studied concentration range 30-55 vol% particles. The mechanical strength of the solidified capillary suspensions, characterized by the yield stress Y, is measured at the elastic limit for various volume fractions of the particles and the preferentially wetting liquid. A quantitative theoretical model is developed, which relates Y with the maximum of the capillary-bridge force, projected on the shear plane. A semi-empirical expression for the mean number of capillary bridges per particle is proposed. The model agrees very well with the experimental data and gives a quantitative description of the yield stress, which increases with the rise of interfacial tension and with the volume fractions of particles and capillary bridges, but decreases with the rise of particle radius and contact angle. The quantitative description of capillary force is based on the exact theory and numerical calculation of the capillary bridge profile at various bridge volumes and contact angles. An analytical formula for Y is also derived. The comparison of the theoretical and experimental strain at the elastic limit reveals that the fluidization of the capillary suspension takes place only in a deformation zone of thickness up to several hundred particle diameters, which is adjacent to the rheometer's mobile plate. The reported experimental results refer to water-continuous suspension with hydrophobic particles and oily capillary bridges. The comparison of data for bridges from soybean oil and hexadecane surprisingly indicate that the yield strength is

21 CFR 864.6150 - Capillary blood collection tube.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Capillary blood collection tube. 864.6150 Section 864.6150 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Manual Hematology Devices § 864.6150 Capillary...

Capillary sieving electrophoresis and micellar electrokinetic capillary chromatography produce highly correlated separation of tryptic digests

Science.gov (United States)

Dickerson, Jane A.; Dovichi, Norman J.

2011-01-01

We perform two-dimensional capillary electrophoresis on fluorescently labeled proteins and peptides. Capillary sieving electrophoresis was performed in the first dimension and micellar electrokinetic capillary chromatography was performed in the second. A cellular homogenate was labeled with the fluorogenic reagent FQ and separated using the system. This homogenate generated a pair of ridges; the first had essentially constant migration time in the CSE dimension, while the second had essentially constant migration time in the MEKC dimension. In addition a few spots were scattered through the electropherogram. The same homogenate was digested using trypsin, and then labeled and subjected to the two dimensional separation. In this case, the two ridges observed from the original two-dimensional separation disappeared, and were replaced by a set of spots that fell along the diagonal. Those spots were identified using a local-maximum algorithm and each was fit using a two-dimensional Gaussian surface by an unsupervised nonlinear least squares regression algorithm. The migration times of the tryptic digest components were highly correlated (r = 0.862). When the slowest migrating components were eliminated from the analysis, the correlation coefficient improved to r = 0.956. PMID:20564272

A Capillary-Based Static Phase Separator for Highly Variable Wetting Conditions

Science.gov (United States)

Thomas, Evan A.; Graf, John C.; Weislogel, Mark M.

2010-01-01

The invention, a static phase separator (SPS), uses airflow and capillary wetting characteristics to passively separate a two-phase (liquid and air) flow. The device accommodates highly variable liquid wetting characteristics. The resultant design allows for a range of wetting properties from about 0 to over 90 advancing contact angle, with frequent complete separation of liquid from gas observed when using appropriately scaled test conditions. Additionally, the design accommodates a range of air-to-liquid flow-rate ratios from only liquid flow to over 200:1 air-to-liquid flow rate. The SPS uses a helix input section with an ice-cream-cone-shaped constant area cross section (see figure). The wedge portion of the cross section is on the outer edge of the helix, and collects the liquid via centripetal acceleration. The helix then passes into an increasing cross-sectional area vane region. The liquid in the helix wedge is directed into the top of capillary wedges in the liquid containment section. The transition from diffuser to containment section includes a 90 change in capillary pumping direction, while maintaining inertial direction. This serves to impinge the liquid into the two off-center symmetrical vanes by the airflow. Rather than the airflow serving to shear liquid away from the capillary vanes, the design allows for further penetration of the liquid into the vanes by the air shear. This is also assisted by locating the air exit ports downstream of the liquid drain port. Additionally, any droplets not contained in the capillary vanes are re-entrained downstream by a third opposing capillary vane, which directs liquid back toward the liquid drain port. Finally, the dual air exit ports serve to slow the airflow down, and to reduce the likelihood of shear. The ports are stove-piped into the cavity to form an unfriendly capillary surface for a wetting fluid to carryover. The liquid drain port is located at the start of the containment region, allowing for

Assessment of the Relationship between Diabetic Retinopathy and Nailfold Capillaries in Type 2 Diabetics with a Noninvasive Method: Nailfold Videocapillaroscopy

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Seyit Uyar

2016-01-01

Full Text Available Background and Objectives. Nailfold capillaroscopy is an easy and noninvasive technique used to investigate dermal microvasculature. Traditional investigations of vascularity do not detect changes until they are well-established in type 2 diabetics. The objective of the current study was to evaluate nailfold capillaries in type 2 diabetes mellitus patients and to determine the association of retinopathy with changes in the nailfold capillaries. Materials and Methods. Capillaroscopic findings by nailfold capillaroscopy and fundoscopic examinations were assessed in 216 patients with type 2 diabetes mellitus and 101 healthy controls included in this prospective study. Results. Retinopathy was detected in 43.05% of diabetic patients (n=93. Capillaroscopic findings including tortuosity (p<0.001, bushy capillary (p<0.001, neoformation (p<0.001, bizarre capillary (p<0.001, microhemorrhage (p=0.001, capillary ectasia (p=0.002, and aneurysm (p=0.004 were significantly higher in diabetic group than control group. In logistic regression analysis, only tortuosity was shown significant (OR, 2.16; p=0.036. There was also a significant relation between diabetes duration and most of the capillaroscopic findings. Conclusion. Capillaroscopic changes were found to be correlated with diabetic retinopathy, in particular with longer disease duration in our study. Capillaroscopic imaging could be a useful new technique for assessment of diabetic microvascular changes.

Capillary viscosimetry on ferrofluids

International Nuclear Information System (INIS)

Pop, L M; Odenbach, S

2008-01-01

Experiments performed for different ferrofluids under shear flow have shown that an increase of the magnetic field strength applied to the sample yields an increase of the fluid's viscosity, the so called magnetoviscous effect. It has been shown that the magnitude of the effect is strongly related to the modification of the microstructure of ferrofluids and can be influenced by varying both the dipole-dipole interaction between the particles and the concentration of large particles within the fluid. This result has been further used to synthesize new ferrofluids which, on one hand, are more compatible for technical applications but, on the other hand, led to difficulties for the experimenters in measuring the viscous behavior in the presence of a magnetic field. To overcome this problem, a specially designed ferrofluid-compatible capillary viscometer has been developed. Within this paper, the experimental setup as well as experimental results concerning the investigation of the magnetoviscous effect in both diluted and concentrated cobalt-based ferrofluids are presented

Capillary regeneration in scleroderma: stem cell therapy reverses phenotype?

Directory of Open Access Journals (Sweden)

Jo N Fleming

2008-01-01

Full Text Available Scleroderma is an autoimmune disease with a characteristic vascular pathology. The vasculopathy associated with scleroderma is one of the major contributors to the clinical manifestations of the disease.We used immunohistochemical and mRNA in situ hybridization techniques to characterize this vasculopathy and showed with morphometry that scleroderma has true capillary rarefaction. We compared skin biopsies from 23 scleroderma patients and 24 normal controls and 7 scleroderma patients who had undergone high dose immunosuppressive therapy followed by autologous hematopoietic cell transplant. Along with the loss of capillaries there was a dramatic change in endothelial phenotype in the residual vessels. The molecules defining this phenotype are: vascular endothelial cadherin, a supposedly universal endothelial marker required for tube formation (lost in the scleroderma tissue, antiangiogenic interferon alpha (overexpressed in the scleroderma dermis and RGS5, a signaling molecule whose expression coincides with the end of branching morphogenesis during development and tumor angiogenesis (also overexpressed in scleroderma skin. Following high dose immunosuppressive therapy, patients experienced clinical improvement and 5 of the 7 patients with scleroderma had increased capillary counts. It was also observed in the same 5 patients, that the interferon alpha and vascular endothelial cadherin had returned to normal as other clinical signs in the skin regressed, and in all 7 patients, RGS5 had returned to normal.These data provide the first objective evidence for loss of vessels in scleroderma and show that this phenomenon is reversible. Coordinate changes in expression of three molecules already implicated in angiogenesis or anti-angiogenesis suggest that control of expression of these three molecules may be the underlying mechanism for at least the vascular component of this disease. Since rarefaction has been little studied, these data may have

Reducing the Edge Chipping for Capillary End Face Grinding and Polishing

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Hošek J.

2013-05-01

Full Text Available This paper presents results of glass capillary end face grinding and polishing by approach that reduces the edge chipping. Brittle materials have natural tendency for edge chipping what leads to beveling the sharp edges. Not beveled sharp edges on glass capillary are important for special applications like surface tension measurement of small liquid samples. We use common grinding and polishing process for capillary end face machining modified with gradual decreasing of grinding load based on the relation of the critical chipping load. Achieved surface roughness is measured using atomic force microscopy (AFM. Capillary inner edge quality is checked both with optical microscopes and electron microscope too. We achieved a non-chipped capillary inner edge with radius down to 100 nm.

On the performance of capillary barriers as landfill cover

Science.gov (United States)

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.

On the performance of capillary barriers as landfill cover

Directory of Open Access Journals (Sweden)

M. Kämpf

1997-01-01

Full Text Available 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.

Metabolic Memory Phenomenon and Accumulation of Peroxynitrite in Retinal Capillaries

Directory of Open Access Journals (Sweden)

Renu A. Kowluru

2007-01-01

Full Text Available Aim. Diabetic retinopathy resists reversal after good glycemic control (GC is reinitiated, and preexisting damage at the time of intervention is considered as the major factor in determining the outcome of the GC. This study is to investigate the role of peroxynitrite accumulation in the retinal capillaries in the failure of retinopathy to reverse after reestablishment of GC, and to determine the effect of this reversal on the activity of the enzyme responsible for scavenging mitochondrial superoxide, MnSOD. Methods. In streptozotocin-diabetic rats, 6 months of poor glycemic control (PC, glycated hemoglobin, GHb>12.0% was followed by 6 additional months of GC (GHb about 6%. The trypsin-digested retinal microvessels were prepared for immunostaining of nitrotyrosine (a measure of peroxynitrite and for counting the number of acellular capillaries (a measure of histopathology. The retina from the other eye was used to quantify nitrotyrosine concentration, MnSOD activity and the total antioxidant capacity. Results. Reversal of hyperglycemia after 6 months of PC had no significant effect on nitrotyrosine concentration in the retina, on the nitrotyrosine-positive retinal capillary cells and on the number of acellular capillaries; the values were similar in PC-GC and PC groups. In the same rats retinal MnSOD activity remained inhibited and the total antioxidant capacity was subnormal 6 months after cessation of PC. Conclusions. Peroxynitrite accumulation in the retinal microvasculature, the site of histopathology, fails to normalize after reversal of hyperglycemia, and superoxide remains inadequately scavenged. This failure of reversal of peroxynitrite accumulation could be, in part, responsible for the resistance of diabetic retinopathy to reverse after termination of PC.

Capillary electrophoresis and nanomaterials - Part I: Capillary electrophoresis of nanomaterials.

Science.gov (United States)

Adam, Vojtech; Vaculovicova, Marketa

2017-10-01

Nanomaterials are in analytical science used for a broad range of purposes, covering the area of sample pretreatment as well as separation, detection, and identification of target molecules. This part of the review covers capillary electrophoresis (CE) of nanomaterials and focuses on the application of CE as a method for characterization used during nanomaterial synthesis and modification as well as the monitoring of their properties and interactions with other molecules. The heterogeneity of the nanomaterial family is extremely large. Depending on different definitions of the term Nanomaterial/Nanoparticle, the group may cover metal and polymeric nanoparticles, carbon nanomaterials, liposomes and even dendrimers. Moreover, these nanomaterials are usually subjected to some kind of surface modification or functionalization, which broadens the diversity even more. Not only for purposes of verification of nanomaterial synthesis and batch-to-batch quality check, but also for determination the polydispersity and for functionality characterization on the nanoparticle surface, has CE offered very beneficial capabilities. Finally, the monitoring of interactions between nanomaterials and other (bio)molecules is easily performed by some kind of capillary electromigration technique. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Assessment of an automated capillary system for Plasmodium vivax microsatellite genotyping.

Science.gov (United States)

Manrique, Paulo; Hoshi, Mari; Fasabi, Manuel; Nolasco, Oscar; Yori, Pablo; Calderón, Martiza; Gilman, Robert H; Kosek, Margaret N; Vinetz, Joseph M; Gamboa, Dionicia

2015-08-21

Several platforms have been used to generate the primary data for microsatellite analysis of malaria parasite genotypes. Each has relative advantages but share a limitation of being time- and cost-intensive. A commercially available automated capillary gel cartridge system was assessed in the microsatellite analysis of Plasmodium vivax diversity in the Peruvian Amazon. The reproducibility and accuracy of a commercially-available automated capillary system, QIAxcel, was assessed using a sequenced PCR product of 227 base pairs. This product was measured 42 times, then 27 P. vivax samples from Peruvian Amazon subjects were analyzed with this instrument using five informative microsatellites. Results from the QIAxcel system were compared with a Sanger-type sequencing machine, the ABI PRISM(®) 3100 Genetic Analyzer. Significant differences were seen between the sequenced amplicons and the results from the QIAxcel instrument. Different runs, plates and cartridges yielded significantly different results. Additionally, allele size decreased with each run by 0.045, or 1 bp, every three plates. QIAxcel and ABI PRISM systems differed in giving different values than those obtained by ABI PRISM, and too many (i.e. inaccurate) alleles per locus were also seen with the automated instrument. While P. vivax diversity could generally be estimated using an automated capillary gel cartridge system, the data demonstrate that this system is not sufficiently precise for reliably identifying parasite strains via microsatellite analysis. This conclusion reached after systematic analysis was due both to inadequate precision and poor reproducibility in measuring PCR product size.

Simulation and application of micro X-ray fluorescence based on an ellipsoidal capillary

Energy Technology Data Exchange (ETDEWEB)

Yang, Jing; Li, Yude; Wang, Xingyi; Zhang, Xiaoyun; Lin, Xiaoyan, E-mail: yangjing_928@126.com

2017-06-15

Highlights: • A micro X-ray fluorescence setup based on an ellipsoidal capillary was presented. • The optimal parameters of ellipsoidal capillary were designed. • The 2D mapping image of biological sample was obtained. - Abstract: A micro X-ray fluorescence setup was presented, based on an ellipsoidal capillary and a traditional laboratorial X-ray source. Using Ray-tracing principle, we have simulated the transmission path of X-ray beam in the ellipsoidal capillary and designed the optimal parameters of the ellipsoidal capillary for the micro X-ray fluorescence setup. We demonstrate that ellipsoidal capillary is well suited as condenser for the micro X-ray fluorescence based on traditional laboratorial X-ray source. Furthermore, we obtain the 2D mapping image of the leaf blade sample by using the ellipsoidal capillary we designed.

Pulmonary capillary haemangiomatosis: a rare cause of pulmonary hypertension.

Science.gov (United States)

Babu, K Anand; Supraja, K; Singh, Raj B

2014-01-01

Pulmonary capillary haemangiomatosis (PCH) is a rare disorder of unknown aetiology, characterised by proliferating capillaries that invade the pulmonary interstitium, alveolar septae and the pulmonary vasculature. It is often mis-diagnosed as primary pulmonary hypertension and pulmonary veno-occlusive disease. Pulmonary capillary haemangiomatosis is a locally aggressive benign vascular neoplasm of the lung. We report the case of a 19-year-old female who was referred to us in the early post-partum period with severe pulmonary artery hypertension, which was diagnosed as PCH by open lung biopsy.

Capillary electrophoresis in a fused-silica capillary with surface roughness gradient

Czech Academy of Sciences Publication Activity Database

Horká, Marie; Šlais, Karel; Karásek, Pavel; Růžička, F.; Šalplachta, Jiří; Šesták, Jozef; Kahle, Vladislav; Roth, Michal

2016-01-01

Roč. 39, č. 19 (2016), s. 3827-3834 ISSN 1615-9306 R&D Projects: GA ČR(CZ) GA16-03749S; GA MZd(CZ) NV16-29916A Institutional support: RVO:68081715 Keywords : capillary electrophoresis * supercritical water * surface roughness gradient Subject RIV: CB - Analytical Chemistry , Separation Impact factor: 2.557, year: 2016

Capillary electrophoresis in a fused-silica capillary with surface roughness gradient

Czech Academy of Sciences Publication Activity Database

Horká, Marie; Šlais, Karel; Karásek, Pavel; Růžička, F.; Šalplachta, Jiří; Šesták, Jozef; Kahle, Vladislav; Roth, Michal

2016-01-01

Roč. 39, č. 19 (2016), s. 3827-3834 ISSN 1615-9306 R&D Projects: GA ČR(CZ) GA16-03749S; GA MZd(CZ) NV16-29916A Institutional support: RVO:68081715 Keywords : capillary electrophoresis * supercritical water * surface roughness gradient Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 2.557, year: 2016

Numerical analysis of capillary entrapment for effective CO{sub 2} aquifer storage

Energy Technology Data Exchange (ETDEWEB)

Uelker, B.; Pusch, G. [Technische Univ. Clausthal (Germany). Inst. fuer Erdoel- und Erdgastechnik; May, F. [Bundesanstalt fuer Geowissenschaften und Rohstoffe, Hannover (Germany)

2007-09-13

The success of underground CO{sub 2} sequestration projects relies on the ability of keeping CO{sub 2} immobilized. The risk of CO{sub 2} leakage into the atmosphere through faults, cap rock formations or wellbore must be evaluated for the long term safety of storage. In case of CO{sub 2} sequestration in a saline aquifer capillary trapping of CO{sub 2} is one of the essential mechanisms controlling the upward and lateral migration of CO{sub 2} plumes after the injection phase. Therefore, assessment of CO{sub 2} immobilization requires accurate modelling of multi phase flow performance. A generic reservoir model was created to examine the impact of the relative permeabilities and capillary forces on capillary trapping. This study reveals how the mechanism of capillary trapping is affected by varying the CO{sub 2} injection rate, hysteresis between drainage and imbibition processes and residual phase saturations. The leakage risk of injected CO{sub 2} in vertical and horizontal wells was also compared to identify the effective injection geometry. Vertical injection across the entire storage formation interval leads to extensive contact with cap rock and leakage through it. Horizontal wells located in the lower part of the formation both increase the aquifer utilization and eliminate contact with cap rock immediately. Thus horizontal wells can be an alternative to inject more CO{sub 2} and minimize leakage. (orig.)

Capillary Pumped Heat Transfer (CHT) Experiment

Science.gov (United States)

Hallinan, Kevin P.; Allen, J. S.

1998-01-01

The operation of Capillary Pumped Loops (CPL's) in low gravity has generally been unable to match ground-based performance. The reason for this poorer performance has been elusive. In order to investigate the behavior of a CPL in low-gravity, an idealized, glass CPL experiment was constructed. This experiment, known as the Capillary-driven Heat Transfer (CHT) experiment, was flown on board the Space Shuttle Columbia in July 1997 during the Microgravity Science Laboratory mission. During the conduct of the CHT experiment an unexpected failure mode was observed. This failure mode was a result of liquid collecting and then eventually bridging the vapor return line. With the vapor return line blocked, the condensate was unable to return to the evaporator and dry-out subsequently followed. The mechanism for this collection and bridging has been associated with long wavelength instabilities of the liquid film forming in the vapor return line. Analysis has shown that vapor line blockage in present generation CPL devices is inevitable. Additionally, previous low-gravity CPL tests have reported the presence of relatively low frequency pressure oscillations during erratic system performance. Analysis reveals that these pressure oscillations are in part a result of long wavelength instabilities present in the evaporator pores, which likewise lead to liquid bridging and vapor entrapment in the porous media. Subsequent evaporation to the trapped vapor increases the vapor pressure. Eventually the vapor pressure causes ejection of the bridged liquid. Recoil stresses depress the meniscus, the vapor pressure rapidly increases, and the heated surface cools. The process then repeats with regularity.

Effect of façade impregnation on feasibility of capillary active thermal internal insulation for a historic dormitory – A hygrothermal simulation study

DEFF Research Database (Denmark)

Finken, Gholam Reza; Bjarløv, Søren Peter; Peuhkuri, Ruut Hannele

2016-01-01

Internal insulation of external walls is known to create moisture performance challenges due to increased moisture levels and condensation risk on the cold side of the insulation. Capillary active/hydrophilic insulations have been introduced to solve these moisture problems, since they are able...... to transport liquid moisture to the inner surface and enable it to dry. Experience with this insulation type is rare in Denmark. In hygrothermal 1D computer simulations, several more or less capillary active insulation systems (AAC, calcium silicate, IQ-Therm) in various thicknesses (30–150 mm) have been....... A moisture safe construction was only achieved when exterior façade impregnation shielding against driving rain was added. The best system showed acceptable relative humidity values both behind the insulation and on the interior surface, a significant increase in minimum temperature on the interior surface...

First attempts to combine capillary tubes with photocathodes

CERN Document Server

Peskov, Vladimir; Sokolova, T; Radionov, I

1999-01-01

We describe our efforts to combine glass capillary plates, operating as a gas amplification structure at approx 1 atm, with photocathodes sensitive to visible light. Such capillary tubes are a by-product of the manufacture of Microchannel Plates and are commercially available. Preliminary tests indicate that gas gains >10 sup 3 could be achieved without photon feedback. With two capillary plates in tandem (double-step multiplication) overall gains up to 10 sup 5 were possible at counting rate <100 Hz/mm sup 2. This approach may open new possibilities for detection of visible photons by gaseous detectors. Potential advantages are: high gains, large sensitive area, high granularity, and insensitivity to magnetic fields.

Performance of a split-type air conditioner matched with coiled adiabatic capillary tubes using HCFC22 and HC290

International Nuclear Information System (INIS)

Zhou, Guobing; Zhang, Yufeng

2010-01-01

This paper experimentally investigated the system performance of a split-type air conditioner matching with different coiled adiabatic capillary tubes for HCFC22 and HC290. Experiments were carried out in a room-type calorimeter. The results have shown that (1) similar cooling effects can be achieved by matching various capillary tubes of different inner diameters; (2) parallel capillary tubes presented better system performance and flow stability with weaker inlet pressure fluctuations than the single capillary tube; (3) with the coil diameter of the capillary tube increasing from 40 mm to 120 mm, the mass flow rate tended to increase slightly. But the cooling capacity, input power and energy efficiency ratio (EER) did not show evident tendency of change; (4) the refrigerant charge and mass flow rate for HC290 were only 44% and 47% of that for HCFC22, respectively, due to the much lower density. And HC290 had 4.7-6.7% lower cooling capacity and 12.1-12.3% lower input power with respect to HCFC22. However, the EER of HC290 can be 8.5% higher than that of HCFC22, which exhibits the advantage of using HC290. In addition, the experimental uncertainties were analyzed and some application concerns of HC290 were discussed.

Role of mixed boundaries on flow in open capillary channels with curved air-water interfaces.

Science.gov (United States)

Zheng, Wenjuan; Wang, Lian-Ping; Or, Dani; Lazouskaya, Volha; Jin, Yan

2012-09-04

Flow in unsaturated porous media or in engineered microfluidic systems is dominated by capillary and viscous forces. Consequently, flow regimes may differ markedly from conventional flows, reflecting strong interfacial influences on small bodies of flowing liquids. In this work, we visualized liquid transport patterns in open capillary channels with a range of opening sizes from 0.6 to 5.0 mm using laser scanning confocal microscopy combined with fluorescent latex particles (1.0 μm) as tracers at a mean velocity of ∼0.50 mm s(-1). The observed velocity profiles indicate limited mobility at the air-water interface. The application of the Stokes equation with mixed boundary conditions (i.e., no slip on the channel walls and partial slip or shear stress at the air-water interface) clearly illustrates the increasing importance of interfacial shear stress with decreasing channel size. Interfacial shear stress emerges from the velocity gradient from the adjoining no-slip walls to the center where flow is trapped in a region in which capillary forces dominate. In addition, the increased contribution of capillary forces (relative to viscous forces) to flow on the microscale leads to increased interfacial curvature, which, together with interfacial shear stress, affects the velocity distribution and flow pattern (e.g., reverse flow in the contact line region). We found that partial slip, rather than the commonly used stress-free condition, provided a more accurate description of the boundary condition at the confined air-water interface, reflecting the key role that surface/interface effects play in controlling flow behavior on the nanoscale and microscale.

Atrial natriuretic factor increases vascular permeability

International Nuclear Information System (INIS)

Lockette, W.; Brennaman, B.

1990-01-01

An increase in central blood volume in microgravity may result in increased plasma levels of atrial natriuretic factor (ANF). Since elevations in plasma ANF are found in clinical syndromes associated with edema, and since space motion sickness induced by microgravity is associated with an increase in central blood volume and facial edema, we determined whether ANF increases capillary permeability to plasma protein. Conscious, bilaterally nephrectomized male rats were infused with either saline, ANF + saline, or hexamethonium + saline over 2 h following bolus injections of 125I-albumin and 14C-dextran of similar molecular size. Blood pressure was monitored and serial determinations of hematocrits were made. Animals infused with 1.0 micrograms.kg-1.min-1 ANF had significantly higher hematocrits than animals infused with saline vehicle. Infusion of ANF increased the extravasation of 125I-albumin, but not 14C-dextran from the intravascular compartment. ANF also induced a depressor response in rats, but the change in blood pressure did not account for changes in capillary permeability to albumin; similar depressor responses induced by hexamethonium were not accompanied by increased extravasation of albumin from the intravascular compartment. ANF may decrease plasma volume by increasing permeability to albumin, and this effect of ANF may account for some of the signs and symptoms of space motion sickness

Separation of oligopeptides, nucleobases, nucleosides and nucleotides using capillary electrophoresis/electrochromatography with sol–gel modified inner capillary wall

Czech Academy of Sciences Publication Activity Database

Svobodová, Jana; Kofroňová, Olga; Benada, Oldřich; Král, V.; Mikšík, Ivan

2017-01-01

Roč. 1517, Sep 29 (2017), s. 185-194 ISSN 0021-9673 R&D Projects: GA ČR(CZ) GA15-01948S; GA MŠk(CZ) LO1509 Institutional support: RVO:67985823 ; RVO:61388971 Keywords : capillary electrochromatography (CEC) * open-tubular capillary electrochromatography (OT-CEC) * nucleo-compounds * oligopeptides * sol–gel methods * Porphyrin * scanning electron microscopy (SEM) Subject RIV: CB - Analytical Chemistry, Separation; CE - Biochemistry (MBU-M) OBOR OECD: Analytical chemistry; Biochemistry and molecular biology (MBU-M) Impact factor: 3.981, year: 2016

Validity of using modified capillary column with larger diameter to study the Cs diffusion in local Taiwan laterite

International Nuclear Information System (INIS)

Tsing-Hai Wang; National Tsing Hua University, Hsinchu, Taiwan; Wen-Chun Yeh; Shih-Chin Tsai; Yi-Lin Jan; Shi-Ping Teng

2008-01-01

We have examined the working diameter of capillary columns with diameter of 5, 7, 10 and 20 mm. These modified capillary columns were carefully filled with local Taiwan laterite (LTL). The porosity and density of these packed columns was 0.51±0.02 g/g and 1.27±0.05 g/cm 3 , respectively. The diffusion experiments were then carried out in synthetic groundwater with Cs loading of 0.1mM at room temperature. Experimental results have shown that the diffusion profiles of modified capillary columns fit Fick's second law very well. This result revealed that the working diameter of a capillary column can be expanded to at least to 20 mm without affecting the validity of the derived diffusion coefficients. Among these columns, the ones with 5 mm diameter show the most consistent results of the derived K d , apparent and effective diffusion coefficients. Although the derived distribution and effective diffusion coefficients slightly decrease as the diameter of these columns increases due to the increase of the solid/liquid ratio. These values are still informative of the Cs diffusion in local Taiwan laterite. Moreover, our results clearly demonstrate the potential of using 'modified capillary method' to study the diffusion behaviors of concerned radionuclide because columns with large diameter enable the filling with more versatile geological substances. (author)

Nationwide survey of policies and practices related to capillary blood sampling in medical laboratories in Croatia

OpenAIRE

Lenicek Krleza, Jasna

2014-01-01

Introduction: Capillary sampling is increasingly used to obtain blood for laboratory tests in volumes as small as necessary and as non-invasively as possible. Whether capillary blood sampling is also frequent in Croatia, and whether it is performed according to international laboratory standards is unclear. Materials and methods: All medical laboratories that participate in the Croatian National External Quality Assessment Program (N = 204) were surveyed on-line to collect information about t...

Determination of flotation reagents used in tin-mining by capillary electrophoresis.

Science.gov (United States)

Hissner, F; Daus, B; Mattusch, J; Heinig, K

1999-08-20

Alkyl xanthates (O-alkyl dithiocarbonates) and phosphonates are important organic collectors for the flotation of metals from crude ore. Leaching from waste dumps into river and ground water, these substances can cause environmental pollution. A capillary electrophoretic method for the routine determination of ethyl, isopropyl, hexyl xanthate, and styrene phosphonate has been developed. Separation within 12 min could be achieved in borate pH 8.8 performing UV detection at 254 and 300 nm simultaneously. To improve the limits of detection obtained with hydrodynamic injection (0.4-1.5 ppm), field amplified sample injection (FASI) and stacking were investigated. An increase in sensitivity up to 4-8 fold could be achieved by pressure assisted FASI. Applying a stacking method to enrich the analytes by filling the capillary with sample solution to one third of its length, the limits of detection could be decreased to 10-40 ppb. Water samples from a former tin ore mining area have been analyzed using the optimized stacking technique. Quantitation was performed by standard addition. Good precision and accuracy were obtained, making this robust capillary electrophoretic method well-suited for routine analysis.

Sheath-flow electrochemical detection of amino acids with a copper wire electrode in capillary electrophoresis.

Science.gov (United States)

Inoue, Junji; Kaneta, Takashi; Imasaka, Totaro

2012-09-01

Here, we report the detection of native amino acids using a sheath-flow electrochemical detector with a working electrode made of copper wire. A separation capillary that was inserted into a platinum tube in the detector acted as a grounded electrode for electrophoresis and as a flow channel for sheath liquid. Sheath liquid flowed outside the capillary to support the transport of the separated analytes to the working electrode for electrochemical detection. The copper wire electrode was aligned at the outlet of the capillary in a wall-jet configuration. Amino acids injected into the capillary were separated following elution from the end of the capillary and detection by the copper electrode. Three kinds of copper electrodes with different diameters-50, 125, and 300 μm-were examined to investigate the effect of the electrode diameter on sensitivity. The peak widths of the analytes were independent of the diameter of the working electrode, while the 300-μm electrode led to a decrease in the signal-to-noise ratio compared with the 50- and 125-μm electrodes, which showed no significant difference. The flow rate of the sheath liquid was also varied to optimize the detection conditions. The limits of detection for amino acids ranged from 4.4 to 27 μM under optimal conditions. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Viscoelastic capillary flow: the case of whole blood

Directory of Open Access Journals (Sweden)

David Rabaud

2016-07-01

Full Text Available The dynamics of spontaneous capillary flow of Newtonian fluids is well-known and can be predicted by the Lucas-Washburn-Rideal (LWR law. However a wide variety of viscoelastic fluids such as alginate, xanthan and blood, does not exhibit the same Newtonian behavior.In this work we consider the Herschel-Bulkley (HB rheological model and Navier-Stokes equation to derive a generic expression that predicts the capillary flow of non-Newtonian fluids. The Herschel-Bulkley rheological model encompasses a wide variety of fluids, including the Power-law fluids (also called Ostwald fluids, the Bingham fluids and the Newtonian fluids. It will be shown that the proposed equation reduces to the Lucas-Washburn-Rideal law for Newtonian fluids and to the Weissenberg-Rabinowitsch-Mooney (WRM law for power-law fluids. Although HB model cannot reduce to Casson’s law, which is often used to model whole blood rheology, HB model can fit the whole blood rheology with the same accuracy.Our generalized expression for the capillary flow of non-Newtonian fluid was used to accurately fit capillary flow of whole blood. The capillary filling of a cylindrical microchannel by whole blood was monitored. The blood first exhibited a Newtonian behavior, then after 7 cm low shear stress and rouleaux formation made LWR fails to fit the data: the blood could not be considered as Newtonian anymore. This non-Newtonian behavior was successfully fit by the proposed equation.

Intramuscular capillary-type hemangioma: radiologic-pathologic correlation

Energy Technology Data Exchange (ETDEWEB)

Yilmaz, Sabri; Alomari, Ahmad I.; Chaudry, Gulraiz [Boston Children' s Hospital and Harvard Medical School, Vascular Anomalies Center, Boston, MA (United States); Boston Children' s Hospital and Harvard Medical School, Division of Vascular and Interventional Radiology, Boston, MA (United States); Kozakewich, Harry P. [Boston Children' s Hospital and Harvard Medical School, Vascular Anomalies Center, Boston, MA (United States); Boston Children' s Hospital and Harvard Medical School, Department of Pathology, Boston, MA (United States); Fishman, Steven J. [Boston Children' s Hospital and Harvard Medical School, Vascular Anomalies Center, Boston, MA (United States); Boston Children' s Hospital and Harvard Medical School, Department of Surgery, Boston, MA (United States); Mulliken, John B. [Boston Children' s Hospital and Harvard Medical School, Vascular Anomalies Center, Boston, MA (United States); Boston Children' s Hospital and Harvard Medical School, Department of Plastic and Oral Surgery, Boston, MA (United States)

2014-05-15

Infantile hemangiomas demonstrate a pattern of proliferative growth in infancy followed by a slow phase of involution. In contrast a rare type of vascular tumor, intramuscular capillary-type hemangioma, usually presents beyond the period of infancy with nonspecific symptoms and no evidence of involution. The purpose of this study was to characterize the clinical, imaging, histopathological characteristics and management of intramuscular capillary-type hemangioma. We performed a retrospective review of a 20-year period to identify children diagnosed with intramuscular capillary-type hemangioma. Patient demographics, imaging and histopathological findings were recorded. We included 18 children (10 boys, 8 girls) with histologically proven intramuscular capillary-type hemangioma - and adequate imaging. The mean age at presentation was 8.1 years (range 1 day to 19 years). Twelve lesions involved muscles of the extremities, 4 were located in the trunk and 2 were in the head and neck. MRI had been performed in all children and demonstrated a soft-tissue mass with flow voids, consistent with fast flow. The lesion was well-circumscribed in 16 children and intralesional fat was seen in 14. Doppler US demonstrated a heterogeneous lesion, predominantly isoechoic to surrounding muscle, with enlarged arterial feeders. Enlarged feeding arteries, inhomogeneous blush and lack of arteriovenous shunting were noted on angiography (n = 5). The most common histopathological findings were lobules of capillaries with plump endothelium and at least some adipose tissue. The lesions were excised in six children. Two children were lost to follow-up. In the remaining 10, follow-up MRI studies ranging from 3 months to 10 years showed that the lesion enlarged in proportion to the child (n = 7), demonstrated slow growth (n = 2) or remained stable (n = 1). There was no change in imaging characteristics on follow-up. Intramuscular capillary-type hemangioma is a rare benign vascular tumor of

Capillary pressure - saturation relations for supercritical CO2 and brine: Implications for capillary/residual trapping in carbonate reservoirs during geologic carbon sequestration

Science.gov (United States)

Wang, S.; Tokunaga, T. K.

2014-12-01

In geologic carbon sequestration (GCS), data on capillary pressure (Pc) - saturation (Sw) relations are routinely needed to appraise reservoir processes. Capillarity and its hysteresis have been often experimentally studied in oil-water, gas-water and three phase gas-oil-water systems, but fewer works have been reported on scCO2-water under in-situ reservoir conditions. Here, Pc-Sw relations of supercritical (sc) CO2 displacing brine, and brine rewetting the porous medium to trap scCO2 were studied to understand CO2 transport and trapping behavior in carbonate reservoirs under representative reservoir conditions. High-quality drainage and imbibition (and associated capillary pressure hysteresis) curves were measured under elevated temperature and pressure (45 ºC, 8.5 and 12 MPa) for scCO2-brine as well as at room temperature and pressure (23 ºC, 0.1 MPa) for air-brine in unconsolidated limestone and dolomite sand columns using newly developed semi-automated multistep outflow-inflow porous plate apparatus. Drainage and imbibition curves for scCO2-brine deviated from the universal scaling curves for hydrophilic interactions (with greater deviation under higher pressure) and shifted to lower Pc than predicted based on interfacial tension (IFT) changes. Augmented scaling incorporating differences in IFT and contact angle improved the scaling results but the scaled curves still did not converge onto the universal curves. Equilibrium residual trapping of the nonwetting phase was determined at Pc =0 during imbibition. The capillary-trapped amounts of scCO2 were significantly larger than for air. It is concluded that the deviations from the universal capillary scaling curves are caused by scCO2-induced wettability alteration, given the fact that pore geometry remained constant and IFT is well constrained. In-situ wettability alteration by reactive scCO2 is of critical importance and must be accounted for to achieve reliable predictions of CO2 behavior in GCS reservoirs.

Influence of the nature of interfaces on the capillary transport in layered materials

DEFF Research Database (Denmark)

Derluyn, Hannelore; Janssen, Hans; Carmeliet, Jan

2011-01-01

This paper presents an experimental and quantitative analysis of capillary transport across the interface brick–mortar joint in masonry. Moisture profiles are measured with X-ray projection. The influence of curing conditions is analyzed by considering three types of mortars: cured in a mould......, between capillary wet and dry bricks. A decrease in moisture inflow for the mortars cured between bricks is measured. The pore structure and the moisture transport properties of mortar change significantly due to water extraction from the initially wet mortar to the bricks during curing. Numerical...... simulations reveal the existence of a hydraulic interface resistance between brick and wet/dry cured mortar....

Evaluation of Tillandsia capillaris Ruiz amd Pav. f. capillaris as biomonitor of atmospheric pollution in Argentina

Energy Technology Data Exchange (ETDEWEB)

Pignata, M.L. [Univ. Nacional de Cordoba, Cordoba (Argentina). Facultad de Ciencias Exactas, Fisicas y Naturales]|[Instituto Multidisciplinario de Biologia Vegetal (IMBIV-UNC), Cordoba (Argentina); Wannaz, E.D.; Martinez, M.S.; Caminotti, G. [Univ. Nacional de Cordoba, Cordoba (Argentina). Facultad de Ciencias Exactas, Fisicas y Naturales

2002-07-01

The behaviour of Tillandsia capillaris Ruiz and Pav. f. capillaris, when exposed to atmospheric pollutants, was assessed by measuring chemical parameters indicating foliar damage and the contents of some heavy metals. Samples were transplanted to three sites in the City of Cordoba and were collected back after 15, 30, 60 and 90 days of exposure. At the same time, samples coming from the collection site were analyzed for each of said exposure times. Chlorophylls, hydroperoxy conjugated dienes, water contents, malondialdehyde, sulfur, Cu, Pb, Ni, Co, Mn, Zn and Fe were measured in the samples. A Foliar Damage Index was calculated from some of these parameters. (orig.)

Intracerebral Capillary Hemangioma: A Case Report

Energy Technology Data Exchange (ETDEWEB)

Youn, In Young; Kim, Jae Kyun; Byun, Jun Soo [Dept. of Radiology, Chung Ang University Medical Center, Chung Ang University College of Medicine, Seoul (Korea, Republic of); Park, Eon Sub [Dept. of Radiology, Chung Ang University Medical Center, Chung Ang University College of Medicine, Seoul (Korea, Republic of)

2012-01-15

Intracerebral capillary hemangiomas are very rare benign vascular tumors that mostly occur during infancy. We described a 69-year-old man with generalized tonic-clonic seizures who was diagnosed with an intracranial mass. Multidetector computed tomography, magnetic resonance imaging and digital subtraction angiography studies were performed for evaluation of brain, and there was a well-enhancing mass found in the right temporal lobe without a definite feeding vessel. The patient underwent surgery and the pathologic examination demonstrated marked proliferation of small vessels with a lobular pattern in the brain parenchyma, which was confirmed to be capillary hemangioma.

Potential of capillary electrophoresis for the profiling of propolis

NARCIS (Netherlands)

Hilhorst, M.J; Somsen, G.W; de Jong, G.J.

1998-01-01

The usefulness of capillary electrophoresis (CE) with diode array detection for the profiling of Propolis, a hive product, is investigated. Water extracts of Propolis were analyzed with both capillary zone electrophoresis (CZE) at pH 7.0 and 9.3, and micellar electrokinetic chromatography (MEKC)

Effect of air on water capillary flow in silica nanochannels

DEFF Research Database (Denmark)

Zambrano, Harvey; Walther, Jens Honore; Oyarzua, Elton

2013-01-01

, with the fabrication of microsystems integrated by nanochannels, a thorough understanding of the transport of fluids in nanoconfinement is required for a successful operation of the functional parts of such devices. In this work, Molecular Dynamics simulations are conducted to study the spontaneous imbibition of water...... in sub 10 nm silica channels. The capillary filling speed is computed in channels subjected to different air pressures. In order to describe the interactions between the species, an effective force field is developed, which is calibrated by reproducing the water contact angle. The results show...... that the capillary filling speed qualitatively follows the classical Washburn model, however, quantitatively it is lower than expected. Furthermore, it is observed that the deviations increase as air pressure is higher. We attribute the deviations to amounts of air trapped at the silica-water interface which leads...

Myocardial capillary permeability for small hydrophilic indicators during normal physiological conditions and after ischemia and reperfusion

DEFF Research Database (Denmark)

Svendsen, Jesper Hastrup

1991-01-01

Myocardial capillary permeability for small hydrophilic solutes (51Cr-EDTA or 99mTc-DTPA) has been measured using intracoronary indicator bolus injection and external radioactivity registration (the single injection, residue detection method). The method is based on kinetic separation of the inje......Myocardial capillary permeability for small hydrophilic solutes (51Cr-EDTA or 99mTc-DTPA) has been measured using intracoronary indicator bolus injection and external radioactivity registration (the single injection, residue detection method). The method is based on kinetic separation...... including microvascular alterations. In open chest dogs transitory increases in capillary extraction fraction and PdS for small hydrophilic solutes were seen following 20 minutes of regional myocardial ischemia and reperfusion. This response could be inhibited by treatment directed against superoxide...

The free-jet expansion from a capillary source

International Nuclear Information System (INIS)

Miller, D.R.; Fineman, M.A.; Murphy, H.

1985-01-01

This paper presents a comparison of the free-jet expansions originating from an orifice and a capillary by measuring the terminal gas properties. Time-of-flight and intensity data are reported for pure gases (He, Ar, CO 2 ) and mixtures of CO 2 /He, together with condensed dimer intensities for Ar and Co 2 . Pitot tube data are reported for N 2 . The results suggest that the free-jet expansions are nearly the same, provided the capillary is modeled as a non-isentropic Fanno flow process. The Fanno flow is slightly non-adiabatic, which complicates the analysis. Only the condensation kinetics appear strongly sensitive to the differences in the initial conditions for the supersonic expansion; any kinetic process relaxing near the capillary orifice exit would be affected

Delayed post-traumatic capillary haemangioma of the spine.

Science.gov (United States)

Shilton, Hamish; Goldschlager, Tony; Kelman, Anthony; Xenos, Chris

2011-11-01

Capillary haemangiomas are well-circumscribed aggregates of closely packed, thin-walled capillaries separated by connective tissue stroma. In subcutaneous tissue they are termed pyogenic granuloma and commonly follow trauma. They rarely occur in the spine. We present a 43-year-old woman with a 6-week history of thoracic myelopathy and back pain on a background of T7 and T8 vertebral compression fractures from a motor vehicle accident 10 years previously. MRI demonstrated a posteriorly based extradural homogeneously enhancing mass at this level. The lesion was resected and diagnosed histopathologically as a capillary haemangioma. The patient's symptoms resolved and she made an uneventful recovery. The literature is reviewed and the possible pathogenesis is discussed. Copyright © 2011 Elsevier Ltd. All rights reserved.

Cerebral extraction of N-13 ammonia: its dependence on cerebral blood flow and capillary permeability, surface area product

International Nuclear Information System (INIS)

Phelps, M.E.; Huang, S.C.; Kuhl, D.E.; Hoffman, E.J.; Slin, C.

1979-01-01

13 N-labeled ammonia was used to investigate: (1) the cerebral extraction and clearance of ammonia; (2) the mechanicsm by which capillaries accommodate changes in cerebral blood flow (CBF); and (3) its use for the measure of CBF. This was investigated by measuring the single pass extraction of 13 NH 3 in rhesus monkeys during P/sub a/CO 2 induced changes in CBF, and with dog studies using in vitro tissue counting techniques to examine 13 NH 3 extraction in gray and white matter, mixed tissue, and cerebellum during variations in CBF produced by combinations of embolization, local brain compression, and changes in P/sub a/CO 2 . The single pass extraction fraction of 13 NH 3 varied from about 70 to 20% over a CBF range of 12 to 140cc/min/100gms. Capillary permeability-surface area product (PS) estimates from this data and the dog experiments show PS increasing with CBF. The magnitude and rate of increase in PS with CBF was highest in gray matter > mixed tissue > white matter. Tissue extraction of 13 NH 3 vs CBF relationship was best described by a unidirectional transport model in which CBF increases by both recruitment of capillaries and by increases of blood velocity in open capillaries. Glutamine synthetase, which incorporates 13 NH 3 into glutamine, appears to be anatomically located in astrocytes in general and specifically in the astrocytic pericapillary end-feet that are in direct contact with gray and white matter capillaries. The net 13 NH 3 extraction subsequent to an i.v. injection increases nonlinearly with CBF. Doubling or halving basal CBF produced from 40 to 50% changes in the 13 N tissue concentrations with further increases in CBF associated with progressively smaller changes in 13 N concentrations. 13 NH 3 appears to be a good tracer for the detection of cerebral ischemia with positron tomography but exhibits a poor response at high values of CBF

New type of capillary for use as ion beam collimator and air-vacuum interface

Energy Technology Data Exchange (ETDEWEB)

Stoytschew, V., E-mail: valostoytschew@hotmail.com [Ruđer Bošković Institute, Bijenicka Cesta 54, 10000 Zagreb (Croatia); Schulte-Borchers, M. [Laboratory of Ion Beam Physics, ETH Zurich, Otto-Stern-Weg 5, CH-8093 Zurich (Switzerland); Božičević Mihalića, Iva [Ruđer Bošković Institute, Bijenicka Cesta 54, 10000 Zagreb (Croatia); Perez, R.D. [FaMAF, Universidad Nacional de Córdoba, (5000) Ciudad Universitaria, Córdoba (Argentina)

2016-08-01

Glass capillaries offer a unique way to combine small diameter ion beam collimation with an air-vacuum interface for ambient pressure ion beam applications. Usually they have an opening diameter of a few microns, limiting the air inflow sufficiently to maintain stable conditions on the vacuum side. As the glass capillaries generally are quite thin and fragile, handling of the capillary in the experiment becomes difficult. They also introduce an X-ray background produced by the capillary wall material, which has to be shielded or subtracted from the data for Particle Induced X-ray Emission (PIXE) applications. To overcome both drawbacks, a new type of conical glass capillary has been developed. It has a higher wall thickness eliminating the low energy X-ray background produced by common capillaries and leading to a more robust lens. The results obtained in first tests show, that this new capillary is suitable for ion beam collimation and encourage further work on the capillary production process to provide thick wall capillaries with an outlet diameter in the single digit micro- or even nanometre range.

In Vivo Microscopy Reveals Extensive Embedding of Capillaries within the Sarcolemma of Skeletal Muscle Fibers

Science.gov (United States)

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

Influence of the capillary on the ignition of the transient spark discharge

International Nuclear Information System (INIS)

Gerling, T; Hoder, T; Brandenburg, R; Bussiahn, R; Weltmann, K-D

2013-01-01

A self-pulsing negative dc discharge in argon generated in a needle-to-plane geometry at open atmosphere is investigated. Additionally, the needle electrode can be surrounded by a quartz capillary. It is shown that the relative position of the capillary end to the needle tip strongly influences the discharge inception and its spatio-temporal dynamics. Without the capillary for the selected working parameters a streamer corona is ignited, but when the capillary surrounds the needle, the transient spark (TS) discharge is ignited after a pre-streamer (PS) occurs. The time between PS and TS discharge depends on the relative capillary end position. The existence of the PS is confirmed by electro-optical characterization. Furthermore, spectrally and spatio-temporally resolved cross-correlation spectroscopy is applied to show the most active region of pre-phase emission activity as indicators for high local electric field strength. The results indicate that with a capillary in place, the necessary energy input of the pre-phase into the system is mainly reduced by additional electrical fields at the capillary edge. Even such a small change as a shift of dielectric surface close to the plasma largely changes the energy balance in the system. (paper)

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

Science.gov (United States)

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 comparison of capillary and venous blood haematocrits of pregnant women in Nigeria: the impact on diagnosis and prevalence of anaemia in pregnancy.

Science.gov (United States)

Dim, Cyril Chukwudi; Ugwu, Emmanuel Onyebuchi; Anyaehie, Ugochukwu Bond; Obioha, Kingsley Chukwu

2014-01-01

Volume of red cells in capillary blood varies from that of venous blood. The magnitude of this variation as well as its impact on the diagnosis of anaemia in pregnancy needs to be studied. This study demonstrates the disparity between capillary and venous PCV in pregnancy. To determine whether capillary blood PCV (cPCV) differed from venous blood PCV (vPCV) of normal pregnant women in Enugu, Nigeria, and its effect on diagnosis and prevalence of anaemia. PCV was estimated using pairs of venous and capillary blood samples from 200 consecutive pregnant women at the Antenatal Clinic of University of Nigeria Teaching Hospital, Enugu, Nigeria. Participants' cPCV (median = 34.0%, IQR = 31.0-35.8) was significantly lower than their vPCV (median = 34.0%, IQR = 32.0-37.0) (Z = -6.85, P prevalence of anaemia among participants using capillary and venous blood was 33.5% (67/200) and 28.0% (56/200), respectively (O.R = 1.3 (CI 95%: 0.85, 1.98),  P = 0.233). Capillary blood PCV was lower than vPCV among pregnant women in Enugu, Nigeria. Nevertheless, the prevalence of anaemia derived from cPCV did not differ significantly from that of vPCV.

Electromagnetohydrodynamic flow of blood and heat transfer in a capillary with thermal radiation

International Nuclear Information System (INIS)

Sinha, A.; Shit, G.C.

2015-01-01

This paper presents a comprehensive theoretical study on heat transfer characteristics together with fully developed electromagnetohydrodynamic flow of blood through a capillary, having electrokinetic effects by considering the constant heat flux at the wall. The effect of thermal radiation and velocity slip condition have been taken into account. A rigorous mathematical model for describing Joule heating in electro-osmotic flow of blood including the Poisson–Boltzmann equation, the momentum equation and the energy equation is developed. The alterations in the thermal transport phenomenon, induced by the variation of imposed electromagnetic effects, are thoroughly explained through an elegant mathematical formalism. Results presented here pertain to the case where the height of the capillary is much greater than the thickness of electrical double layer comprising the stern and diffuse layers. The essential features of the electromagnetohydrodynamic flow of blood and associated heat transfer characteristics through capillary are clearly highlighted by the variations in the non-dimensional parameters for velocity profile, temperature profile and the Nusselt number. The study reveals that the temperature of blood can be controlled by regulating Joule heating parameter. - Highlights: • Electromagnetohydrodynamic flow of blood in capillary is studied. • Potential electric field is applied for driving elecroosmotic flow of blood. • Effect of thermal radiation, Joule heating and velocity slip is investigated. • Thermal radiation bears the significant change in the temperature field

Electromagnetohydrodynamic flow of blood and heat transfer in a capillary with thermal radiation

Energy Technology Data Exchange (ETDEWEB)

Sinha, A. [Department of Mathematics, Jadavpur University, Kolkata 700032 (India); Shit, G.C., E-mail: gopal_iitkgp@yahoo.co.in [Department of Mathematics, Jadavpur University, Kolkata 700032 (India); Institute of Mathematical Sciences, Chennai 600113 (India)

2015-03-15

This paper presents a comprehensive theoretical study on heat transfer characteristics together with fully developed electromagnetohydrodynamic flow of blood through a capillary, having electrokinetic effects by considering the constant heat flux at the wall. The effect of thermal radiation and velocity slip condition have been taken into account. A rigorous mathematical model for describing Joule heating in electro-osmotic flow of blood including the Poisson–Boltzmann equation, the momentum equation and the energy equation is developed. The alterations in the thermal transport phenomenon, induced by the variation of imposed electromagnetic effects, are thoroughly explained through an elegant mathematical formalism. Results presented here pertain to the case where the height of the capillary is much greater than the thickness of electrical double layer comprising the stern and diffuse layers. The essential features of the electromagnetohydrodynamic flow of blood and associated heat transfer characteristics through capillary are clearly highlighted by the variations in the non-dimensional parameters for velocity profile, temperature profile and the Nusselt number. The study reveals that the temperature of blood can be controlled by regulating Joule heating parameter. - Highlights: • Electromagnetohydrodynamic flow of blood in capillary is studied. • Potential electric field is applied for driving elecroosmotic flow of blood. • Effect of thermal radiation, Joule heating and velocity slip is investigated. • Thermal radiation bears the significant change in the temperature field.

Diffusive-dispersive mass transfer in the capillary fringe: Impact of water table fluctuations and heterogeneities

DEFF Research Database (Denmark)

Grathwohl, Peter; Haberer, Cristina; Ye, Yu

Diffusive–dispersive mass transfer in the capillary fringe is important for many groundwater quality issues such as transfer of volatile compounds into (and out of) the groundwater, the supply of oxygen for aerobic degradation of hydrocarbons as well as for precipitation of minerals (e.g. iron...... hydroxides). 2D-laboratory scale experiments were used to investigate the transfer of oxygen into groundwater under non-reactive and reactive conditions, at steady state and with water table fluctuations. Results show that transfer of oxygen is limited by transverse dispersion in the capillary fringe...... and the dispersion coefficients are the same as below the water table. Water table fluctuations cause temporarily increased fluxes of oxygen into groundwater during draining conditions and entrapped air after water table rise. High-permeability inclusions in the capillary fringe enhance mass transfer of oxygen...

Simulation and application of micro X-ray fluorescence based on an ellipsoidal capillary

Science.gov (United States)

Yang, Jing; Li, Yude; Wang, Xingyi; Zhang, Xiaoyun; Lin, Xiaoyan

2017-06-01

A micro X-ray fluorescence setup was presented, based on an ellipsoidal capillary and a traditional laboratorial X-ray source. Using Ray-tracing principle, we have simulated the transmission path of X-ray beam in the ellipsoidal capillary and designed the optimal parameters of the ellipsoidal capillary for the micro X-ray fluorescence setup. We demonstrate that ellipsoidal capillary is well suited as condenser for the micro X-ray fluorescence based on traditional laboratorial X-ray source. Furthermore, we obtain the 2D mapping image of the leaf blade sample by using the ellipsoidal capillary we designed.

Highly efficient capillary polymerase chain reaction using an oscillation droplet microreactor

International Nuclear Information System (INIS)

Liu Dayu; Liang Guangtie; Lei Xiuxia; Chen Bin; Wang Wei; Zhou Xiaomian

2012-01-01

Graphical abstract: An oscillation-flow approach using a droplet reactor was developed to fully explore the potential of continuous-flow PCR. By fully utilizing interfacial chemistry, a water-in-oil (w/o) droplet was automatically generated by allowing an oil–water plug to flow through a polytetrafluoroethylene (PTFE) capillary. Due to the movement of aqueous phase relative to the oil phase, the droplet moves further into the middle of the oil plug with increase in migration distance. The resulting droplet was transported spanning the two heating zones and was employed as the reactor of oscillating-flow PCR. Highlights: ► Droplet formation in a capillary. ► Transport the droplet using oscillation-flow. ► Oscillation droplet PCR. ► Improved reaction efficiency. - Abstract: The current work presents the development of a capillary-based oscillation droplet approach to maximize the potential of a continuous-flow polymerase chain reaction (PCR). Through the full utilization of interfacial chemistry, a water-in-oil (w/o) droplet was generated by allowing an oil–water plug to flow along a polytetrafluoroethylene (PTFE) capillary. The w/o droplet functioned as the reactor for oscillating-flow PCR to provide a stable reaction environment, accelerate reagent mixing, and eliminate surface adsorption. The capillary PCR approach proposed in the current research offers high amplification efficiency, fast reaction speed, and easy system control attributable to the oscillation droplet reactor. Experimental results show that the droplet-based micro-PCR assay requires lower reaction volume (2 μL) and shorter reaction time (12 min) compared with conventional PCR methods. Taking the amplification of the New Delhi metallo-beta-lactamase (NDM-1) gene as an example, the present work demonstrates that the oscillation droplet PCR assay is capable of achieving high efficiency up to 89.5% and a detection limit of 10 DNA copies. The miniature PCR protocol developed in the current

Quantitative analysis by microchip capillary electrophoresis – current limitations and problem-solving strategies

NARCIS (Netherlands)

Revermann, T.; Götz, S.; Künnemeyer, Jens; Karst, U.

2008-01-01

Obstacles and possible solutions for the application of microchip capillary electrophoresis in quantitative analysis are described and critically discussed. Differences between the phenomena occurring during conventional capillary electrophoresis and microchip-based capillary electrophoresis are

Development of high power pumping system for capillary discharge EUV laser

International Nuclear Information System (INIS)

Sakai, Yusuke; Komatsu, Takanori; Watanabe, Masato; Okino, Akitoshi; Hotta, Eiki

2008-01-01

Development of high power pumping system for capillary discharge soft X-ray laser is reported. The pulsed power system consists of a 2.2 μF LC generator, a 2:54 step-up transformer and a 3 nF water capacitor. Taking advantage of high efficiency configuration, step-up ratio of water capacitor voltage to LC generator initial voltage is about 40 times. Consequently, obtained water capacitor voltage reaches about 450 kV when LC generator was charged to 12.5 kV. As a consequent, possibility of charging a water capacitor to 1 MV is demonstrated. With this extremely compact system, discharge current could be increased to nearly 100 kA through moderately long capillary, which leads to generation of high-density and high-temperature plasma column in order to realize EUV laser. (author)

A chip-type thin-layer electrochemical cell coupled with capillary electrophoresis for online separation of electrode reaction products

Energy Technology Data Exchange (ETDEWEB)

He, Jian-Bo, E-mail: jbhe@hfut.edu.cn; Cui, Ting; Zhang, Wen-Wen; Deng, Ning

2013-07-05

Graphical abstract: -- Highlights: •A new coupling of thin-layer electrolysis with capillary electrophoresis (CE). •Rapid electrolysis, direct sampling followed by online CE separation. •At least 13 products of quercetin oxidation were separated. •Thermodynamic and kinetic parameters were determined from CE peak areas. -- Abstract: A coupling technique of thin-layer electrolysis with high-performance capillary electrophoresis/UV–vis technique(EC/HPCE/UV–vis) is developed for online separation and determination of electrode reaction products. A chip-type thin-layer electrolytic (CTE) cell was designed and fabricated, which contains a capillary channel and a background electrolyte reservoir, allowing rapid electrolysis, direct sampling and online electrophoretic separation. This chip-type setup was characterized based on an electrophoresis expression of Nernst equation that was applied to the redox equilibrium of o-tolidine at different potentials. The utility of the method was demonstrated by separating and determining the electro-oxidation products of quercetin in different pH media. Two main products were always found in the studied time, potential and pH ranges. The variety of products increased not only with increasing potential but also with increasing pH value, and in total, at least 13 products were observed in the electropherograms. This work illustrates a novel example of capillary electrophoresis used online with thin-layer electrolysis to separate and detect electrode reaction products.

A chip-type thin-layer electrochemical cell coupled with capillary electrophoresis for online separation of electrode reaction products

International Nuclear Information System (INIS)

He, Jian-Bo; Cui, Ting; Zhang, Wen-Wen; Deng, Ning

2013-01-01

Graphical abstract: -- Highlights: •A new coupling of thin-layer electrolysis with capillary electrophoresis (CE). •Rapid electrolysis, direct sampling followed by online CE separation. •At least 13 products of quercetin oxidation were separated. •Thermodynamic and kinetic parameters were determined from CE peak areas. -- Abstract: A coupling technique of thin-layer electrolysis with high-performance capillary electrophoresis/UV–vis technique(EC/HPCE/UV–vis) is developed for online separation and determination of electrode reaction products. A chip-type thin-layer electrolytic (CTE) cell was designed and fabricated, which contains a capillary channel and a background electrolyte reservoir, allowing rapid electrolysis, direct sampling and online electrophoretic separation. This chip-type setup was characterized based on an electrophoresis expression of Nernst equation that was applied to the redox equilibrium of o-tolidine at different potentials. The utility of the method was demonstrated by separating and determining the electro-oxidation products of quercetin in different pH media. Two main products were always found in the studied time, potential and pH ranges. The variety of products increased not only with increasing potential but also with increasing pH value, and in total, at least 13 products were observed in the electropherograms. This work illustrates a novel example of capillary electrophoresis used online with thin-layer electrolysis to separate and detect electrode reaction products

A capillary viscometer designed for the characterization of biocompatible ferrofluids

Energy Technology Data Exchange (ETDEWEB)

Nowak, J., E-mail: johannes.nowak@tu-dresden.de; Odenbach, S.

2016-08-01

Suspensions of magnetic nanoparticles are receiving a growing interest in biomedical research. These ferrofluids can, e.g., be used for the treatment of cancer, making use of the drug targeting principle or using an artificially induced heating. To enable a safe application the basic properties of the ferrofluids have to be well understood, including the viscosity of the fluids if an external magnetic field is applied. It is well known that the viscosity of ferrofluids rises if a magnetic field is applied, where the rise depends on shear rate and magnetic field strength. In case of biocompatible ferrofluids such investigations proved to be rather complicated as the experimental setup should be close to the actual application to allow justified predictions of the effects which have to be expected. Thus a capillary viscometer, providing a flow situation comparable to the flow in a blood vessel, has been designed. The glass capillary is exchangeable and different inner diameters can be used. The range of the shear rates has been adapted to the range found in the human organism. The application of an external magnetic field is enabled with two different coil setups covering the ranges of magnetic field strengths required on the one hand for a theoretical understanding of particle interaction and resulting changes in viscosity and on the other hand for values necessary for a potential biomedical application. The results show that the newly designed capillary viscometer is suitable to measure the magnetoviscous effect in biocompatible ferrofluids and that the results appear to be consistent with data measured with rotational rheometry. In addition, a strong change of the flow behaviour of a biocompatible ferrofluid was proven for ranges of the shear rate and the magnetic field strength expected for a potential biomedical application. - Highlights: • A capillary viscometer to characterize biocompatible ferrofluids is presented. • Shear rates and capillary diameters

Isoproterenol attenuates high vascular pressure-induced permeability increases in isolated rat lungs.

Science.gov (United States)

Parker, J C; Ivey, C L

1997-12-01

To separate the contributions of cellular and basement membrane components of the alveolar capillary barrier to the increased microvascular permeability induced by high pulmonary venous pressures (Ppv), we subjected isolated rat lungs to increases in Ppv, which increased capillary filtration coefficient (Kfc) without significant hemorrhage (31 cmH2O) and with obvious extravasation of red blood cells (43 cmH2O). Isoproterenol (20 microM) was infused in one group (Iso) to identify a reversible cellular component of injury, and residual blood volumes were measured to assess extravasation of red blood cells through ruptured basement membranes. In untreated lungs (High Ppv group), Kfc increased 6.2 +/- 1.3 and 38.3 +/- 15.2 times baseline during the 31 and 43 cmH2O Ppv states. In Iso lungs, Kfc was 36.2% (P Kfc increases at moderate Ppv, possibly because of an endothelial effect, but it did not affect red cell extravasation at higher vascular pressures.

Capillary waves with surface viscosity

Science.gov (United States)

Shen, Li; Denner, Fabian; Morgan, Neal; van Wachem, Berend; Dini, Daniele

2017-11-01

Experiments over the last 50 years have suggested a correlation between the surface (shear) viscosity and the stability of a foam or emulsion. With recent techniques allowing more accurate measurements of the elusive surface viscosity, we examine this link theoretically using small-amplitude capillary waves in the presence of the Marangoni effect and surface viscosity modelled via the Boussinesq-Scriven model. The surface viscosity effect is found to contribute a damping effect on the amplitude of the capillary wave with subtle differences to the effect of the convective-diffusive Marangoni transport. The general wave dispersion is augmented to take into account the Marangoni and surface viscosity effects, and a first-order correction to the critical damping wavelength is derived. The authors acknowledge the financial support of the Shell University Technology Centre for fuels and lubricants.

Controllable Shrinking of Glass Capillary Nanopores Down to sub-10 nm by Wet-Chemical Silanization for Signal-Enhanced DNA Translocation.

Science.gov (United States)

Xu, Xiaolong; Li, Chuanping; Zhou, Ya; Jin, Yongdong

2017-10-27

Diameter is a major concern for nanopore based sensing. However, directly pulling glass capillary nanopore with diameter down to sub-10 nm is very difficult. So, post treatment is sometimes necessary. Herein, we demonstrate a facile and effective wet-chemical method to shrink the diameter of glass capillary nanopore from several tens of nanometers to sub-10 nm by disodium silicate hydrolysis. Its benefits for DNA translocation are investigated. The shrinking of glass capillary nanopore not only slows down DNA translocation, but also enhances DNA translocation signal and signal-to-noise ratio significantly (102.9 for 6.4 nm glass nanopore, superior than 15 for a 3 nm silicon nitride nanopore). It also affects DNA translocation behaviors, making the approach and glass capillary nanopore platform promising for DNA translocation studies.

VARIABILITY IN FOVEAL AVASCULAR ZONE AND CAPILLARY DENSITY USING OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY MACHINES IN HEALTHY EYES.

Science.gov (United States)

Magrath, George N; Say, Emil Anthony T; Sioufi, Kareem; Ferenczy, Sandor; Samara, Wasim A; Shields, Carol L

2017-11-01

To evaluate the variability in foveal avascular zone (FAZ) and capillary density measurements on optical coherence tomography angiography using Optovue RTVue XR Avanti (OA) (Optovue) and Zeiss Cirrus HD-OCT 5000 (ZC) (Carl Zeiss Meditec). In this prospective, comparative case series, parafoveal (3 × 3 mm) optical coherence tomography angiography scans were obtained on healthy volunteers using both the Avanti and Cirrus. The FAZ area and capillary density at the level of both the superficial and deep capillary plexus were measured automatically using the built-in ReVue software (Optovue) with the Avanti as well as manually using ImageJ (National Institutes of Health) with both machines. There were 50 eyes in 25 healthy volunteers included in the analysis. Mean subject age was 33 years and there were 14 women (56%). On optical coherence tomography, mean central macular thickness was significantly greater on OA (259.1 μm) than ZC (257.6 μm, P = 0.0228). On optical coherence tomography angiography, mean superficial and deep plexus FAZ measured 0.2855 mm and 0.3465 mm on Avanti automated (A-A), 0.2739 mm and 0.3637 mm on Avanti manual (A-M), and 0.2657 mm and 0.3993 mm on Cirrus manual (C-M), respectively. There were no statistically significant differences in superficial plexus FAZ measurements between the A-A and A-M (P = 0.4019) or A-A and C-M (P = 0.1336). The A-M measured significantly larger than C-M (P = 0.0396). Deep plexus FAZ measurements were similar on A-A and A-M (P = 0.6299), but both were significantly less compared with C-M (P machine and technique are consistent and reliable between fellow eyes, significant variability exists in FAZ and capillary density measurements among different machines and techniques. Comparison of measurements across machines and techniques should be considered with caution.

Use of Plastic Capillaries for Macromolecular Crystallization

Science.gov (United States)

Potter, Rachel R.; Hong, Young-Soo; Ciszak, Ewa M.

2003-01-01

Methods of crystallization of biomolecules in plastic capillaries (Nalgene 870 PFA tubing) are presented. These crystallization methods used batch, free-interface liquid- liquid diffusion alone, or a combination with vapor diffusion. Results demonstrated growth of crystals of test proteins such as thaumatin and glucose isomerase, as well as protein studied in our laboratory such dihydrolipoamide dehydrogenase. Once the solutions were loaded in capillaries, they were stored in the tubes in frozen state at cryogenic temperatures until the desired time of activation of crystallization experiments.

Dynamic 99mTc-DTPA radioaerosol lung scanning for the evaluation of alveolar-capillary barrier permeability

International Nuclear Information System (INIS)

Maini, C.L.; Marchetti, L.; Bonetti, M.G.; Giordano, A.; Pistelli, R.; Antonelli Incalzi, R.

1987-01-01

Pulmonary clearance of small droplet 99m Tc-DTPA radioaerosol was studied in 100 patients (12 normal subjects, N; 10 asymptomatic healthy smoker, FA; 31 patients with interstitial lung diseases, IP; 47 patients with chronic obstructive lung disease, BPCO). The first seven minutes of clearance were described with the function At=Ao*exp(-K*t) and the time constant K was considered representative of the 99m Tc-DTPA clearance rate and hence of the alveolar-capillary barrier permeability. Groups FA, IP and BPCO showed a significant (p 99m Tc-DTPA dynamic lung scanning is an easy, non-invasive method to assess derangements of alveolar-capillary barrier permeability secondary to epithelial damage; 2) permeability increase is a very early effect of cigarette smoke damafe to the epithelium; 3) other mechanisms of epithelial injury are present in diffuse lung disease; 4) while the clinical role of this new pathophysiological test is not yet clear, it is likely that it may become a very early marker of pulmonary epithelial damage in diffuse lung disease

An immobilized graphene oxide stationary phase for open-tubular capillary electrochromatography.

Science.gov (United States)

Wang, Chun; de Rooy, Sergio; Lu, Cheng-Fei; Fernand, Vivian; Moore, Leonard; Berton, Paula; Warner, Isiah M

2013-04-01

The research literature currently abounds with studies of graphene-related materials as a result of the extraordinary properties of such materials. On the basis of these citations, it is clear that the range of applications for such materials is substantial. In this manuscript, we report the immobilization of graphene oxide (GO) onto a fused-silica capillary to form a potential stationary phase for use in open-tubular CEC. We successfully incorporated GO through an in situ condensation reaction with (3-aminopropyl)triethoxysilane after silanization with (3-aminopropyl)triethoxysilane on the inner surface of the capillary. This GO-incorporated capillary was then characterized by use of SEM, infrared spectroscopy, and measurements of EOF. The electrochromatographic features of this stationary phase have also been investigated. Evaluation of acquired data indicates high electrochromatographic resolution and good capillary efficiency. Highly reproducible results between runs, days, and capillaries were also obtained. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Hepatic Warm Ischemia-Reperfusion-Induced Increase in Pulmonary Capillary Filtration Is Ameliorated by Administration of a Multidrug Resistance-Associated Protein 1 Inhibitor and Leukotriene D4 Antagonist (MK-571) Through Reducing Neutrophil Infiltration and Pulmonary Inflammation and Oxidative Stress in Rats.

Science.gov (United States)

Yeh, D Y-W; Yang, Y-C; Wang, J-J

2015-05-01

Hepatopulmonary syndrome (HPS) is the major complication subsequent to liver ischemia and reperfusion (I/R) injury after resection or transplantation of liver. Hallmarks of HPS include increases in pulmonary leukotrienes and neutrophil recruitment and infiltrating across capillaries. We aimed to investigate the protective efficacy of MK-571, a multidrug resistance-associated protein 1 inhibitor and leukotriene D4 agonist, against hepatic I/R injury-associated change in capillary filtration. Eighteen Sprague-Dawley male rats were evenly divided into a sham-operated group, a hepatic I/R group, and an MK-571-treated I/R group. MK-571 was administered intraperitoneally 15 min before hepatic ischemia and every 12 hours during reperfusion. Ischemia was conducted by occluding the hepatic artery and portal vein for 30 min, followed by removing the clamps and closing the incision. Forty-eight hours after hepatic ischemia, we assessed the pulmonary capillary filtration coefficient (Kfc) through the use of in vitro-isolated, perfused rat lung preparation. We also measured the lung wet-to-dry weight ratio (W/D) and protein concentration in broncho-alveolar lavage fluid (PCBAL). Lung inflammation and oxidative stress were evaluated by use of tissue tumor necrosis factor (TNF)-α and malondialdehyde levels and lavage differential macrophage and neutrophil cell count. Hepatic I/R injury markedly increased Kfc, W/D, PCBAL, tissue TNF-α level, and differential neutrophil cell count (P < .05). MK-571 treatment reduced neutrophil infiltration and lung inflammation and improved pulmonary capillary filtration, collectively suggesting lung protection. Treatment with MK-571 before and during hepatic ischemia and reperfusion protects lung against pulmonary capillary barrier function impairment through decreasing pulmonary lung inflammation and lavage neutrophils. Copyright © 2015 Elsevier Inc. All rights reserved.

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

Science.gov (United States)

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.

Capillary permeability of 99mTc-DTPA and blood flow rate in the human myocardium determined by intracoronary bolus injection and residue detection

DEFF Research Database (Denmark)

Svendsen, Jesper Hastrup; Efsen, F; Haunsø, S

1992-01-01

.7 ml.(100 g.min)-1 (SD 13.0). Similar values of blood flow rate, capillary extraction fraction and the PS product were determined in 6 patients with localized coronary atheroma without hemodynamically significant coronary artery stenosis (25-50% luminal narrowing). The values for the regional......The aims of the present study were to quantitate blood flow rate and capillary permeability of 99mTc-DTPA in the human myocardium and to assess whether capillary permeability is influenced by the presence of small degree atherosclerotic lesions. Myocardial blood flow rate and capillary permeability......, a mean value of the capillary permeability-surface area (PS) product of 54.0 ml.(100 g.min)-1 (SD 13.0) was determined from a capillary extraction of 55.0% (SD 9.4%) and a regional myocardial plasma flow rate of 74.6 ml.(100 g.min)-1 (SD 6.3) equivalent with a regional myocardial blood flow rate of 121...

Thermodynamics of Capillary Rise: Why Is the Meniscus Curved?

Science.gov (United States)

Henriksson, Ulf; Eriksson, Jan Christer

2004-01-01

The thermodynamics of capillary rise is explained as the gravitational elevation of the whole column of liquid caused by the positive connection between the liquid, and the solid wall of the capillary tube. The curvature of the meniscus is ascribed to the maintenance of a physiochemical balance throughout the gravitational column of liquid.

Pharmacology of post-irradiation damage of blood capillaries

International Nuclear Information System (INIS)

Pospisil, J.; Pouckova, P.

1979-01-01

Available literature data are summed up on the effect of a number of substances on irradiation damage to blood capillaries. The substances include vitamins, bioflavonoids, serotonine, histamine, bradykinin, ACTH, adrenal hormones, vasopressin, estrogens, prostaglandins, escin 1-butanol, diisopropylfluorophosphate, phenoxybenzamine, 1,4-dihydroxybenzenesulphonic acid derivatives, and xi-aminohexanoic acid. The data include the effects of the substances administered before and after irradiation on blood capillary damage and on mortality. (Ha)

Flow Analysis of Isobutane (R-600A) Inside AN Adiabatic Capillary Tube

Science.gov (United States)

Alok, Praveen; Sahu, Debjyoti

2018-02-01

Capillary tubes are simple narrow tubes but the phase change which occurs inside the capillary tubes is complex to analyze. In the present investigation, an attempt is made to analyze the flow of Isobutane (R-600a) inside the coiled capillary tubes for different load conditions by Homogeneous Equilibrium Model. The Length and diameter of the capillary tube not only depend on the pressure and temperature of the condenser and evaporator but also on the cooling load. The present paper investigates the change in dimensions of the coil capillary tube with respect to the change in cooling load on the system for the constant condenser and evaporator conditions. ANSYS CFX (Central Florida Expressway) software is used to study the flow characteristics of the refrigerant. Appropriate helical coil is selected for this analysis.

Increased cerebral oxygen extraction capacity in patients with Alzheimer’s disease

DEFF Research Database (Denmark)

Eskildsen, Simon Fristed; Gyldensted, Louise; Nagenthiraja, Kartheeban

Vascular risk factors are suspected to play a role in the etiology of Alzheimer’s disease. Recently, a model that relates capillary dysfunction to the development of AD was proposed [1]. The model predicts that increased capillary dysfunction leads to increased oxygen extraction in order to support...

Determination of vanillin in vanilla perfumes and air by capillary electrophoresis.

Science.gov (United States)

Minematsu, Saaya; Xuan, Guang-Shan; Wu, Xing-Zheng

2013-12-01

The present study investigated capillary electrophoretic detection of vanillin in vanilla perfume and air. An UV-absorbance detector was used in a home-made capillary electrophoretic instrument. A fused silica capillary (outer diameter: 364 μm, inner diameter: 50 μm) was used as a separation capillary, and a high electric voltage (20 kV) was applied across the two ends of the capillary. Total length of the capillary was 70 cm, and the effective length was 55 cm. Experimental results showed that the vanillin peak was detected at about 600, 450, and 500 seconds when pH of running buffers in CE were 7.2, 9.3, and 11.5, respectively. The peak area of vanillin was proportional to its concentration in the range of 0-10(-2) mol/L. The detection limit was about 10(-5) mol/L. Vanillin concentration in a 1% vanilla perfume sample was determined to be about 3×10(-4) mol/L, agreed well with that obtained by a HPLC method. Furthermore, determination of vanillin in air by combination of CE and active carbon adsorption method was investigated. Copyright © 2013 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

Visual detection of multiple genetically modified organisms in a capillary array.

Science.gov (United States)

Shao, Ning; Chen, Jianwei; Hu, Jiaying; Li, Rong; Zhang, Dabing; Guo, Shujuan; Hui, Junhou; Liu, Peng; Yang, Litao; Tao, Sheng-Ce

2017-01-31

There is an urgent need for rapid, low-cost multiplex methodologies for the monitoring of genetically modified organisms (GMOs). Here, we report a C[combining low line]apillary A[combining low line]rray-based L[combining low line]oop-mediated isothermal amplification for M[combining low line]ultiplex visual detection of nucleic acids (CALM) platform for the simple and rapid monitoring of GMOs. In CALM, loop-mediated isothermal amplification (LAMP) primer sets are pre-fixed to the inner surface of capillaries. The surface of the capillary array is hydrophobic while the capillaries are hydrophilic, enabling the simultaneous loading and separation of the LAMP reaction mixtures into each capillary by capillary forces. LAMP reactions in the capillaries are then performed in parallel, and the results are visually detected by illumination with a hand-held UV device. Using CALM, we successfully detected seven frequently used transgenic genes/elements and five plant endogenous reference genes with high specificity and sensitivity. Moreover, we found that measurements of real-world blind samples by CALM are consistent with results obtained by independent real-time PCRs. Thus, with an ability to detect multiple nucleic acids in a single easy-to-operate test, we believe that CALM will become a widely applied technology in GMO monitoring.

Capillary surfaces in a wedge: Differing contact angles

Science.gov (United States)

Concus, Paul; Finn, Robert

1994-01-01

The possible zero-gravity equilibrium configurations of capillary surfaces u(x, y) in cylindrical containers whose sections are (wedge) domains with corners are investigated mathematically, for the case in which the contact angles on the two sides of the wedge may differ. In such a situation the behavior can depart in significant qualitative ways from that for which the contact angles on the two sides are the same. Conditions are described under which such qualitative changes must occur. Numerically computed surfaces are depicted to indicate the behavior.

Studies on pulsed hollow cathode capillary discharges

Energy Technology Data Exchange (ETDEWEB)

Choi, P; Dumitrescu-Zoita, C; Larour, J; Rous, J [Ecole Polytechnique, 91 - Palaiseau (France). Lab. de Physique des Milieux Ionises; Favre, M; Moreno, J; Chuaqui, H; Wyndham, E [Pontificia Univ. Catolica de Chile, Santiago (Chile). Facultad de Fisica; Zambra, M [Comision Chilena de Energia Nuclear, Santiago (Chile); Wong, C S [Univ. of Malaya, Kuala Lumpur (Malaysia). Plasma Research Lab

1997-12-31

Preliminary results on radiation characteristics of pulsed hollow cathode capillary discharges are presented. The device combines the on axis electron beam assisted ionization capabilities of the transient hollow cathode discharge with a novel high voltage low inductance geometrical design, which integrates the local energy storage into the electrode system. A nanosecond regime high temperature plasma is produced in a long, high aspect ratio capillary, with light emission in the UV to XUV region. The discharge is operated from near vacuum to pressure in the 1000 mTorr range. (author). 2 figs., 7 refs.

TESTICULAR CAPILLARY HEMANGIOMA: DESCRIPTION OF A CASE

Directory of Open Access Journals (Sweden)

A. S. Markova

2012-01-01

Full Text Available The paper describes a clinical case of testicular capillary hemangioma in a 24-year-old man undergone a partial resection of the testis with the intraoperative morphological examination. Testicular capillary hemangioma is a rare benign tumor of a vascular origin, which can be similar to malignant testicular tumors on the clinical presentation, as well as on the imaging methods, in particular to seminoma. The intraoperative histological study can assist in avoiding organ-removing surgical interventions in diagnostically ambiguous cases if a benign testicular tumor is diagnosed.

A two-dimensional model of the pressing section of a paper machine including dynamic capillary effects

KAUST Repository

Iliev, Oleg P.

2013-05-15

Paper production is a problem with significant importance for society; it is also a challenging topic for scientific investigation. This study is concerned with the simulation of the pressing section of a paper machine. A two-dimensional model is developed to account for the water flow within the pressing zone. A Richards-type equation is used to describe the flow in the unsaturated zone. The dynamic capillary pressure-saturation relation is adopted for the paper production process. The mathematical model accounts for the coexistence of saturated and unsaturated zones in a multilayer computational domain. The discretization is performed by the MPFA-O method. Numerical experiments are carried out for parameters that are typical of the production process. The static and dynamic capillary pressure-saturation relations are tested to evaluate the influence of the dynamic capillary effect. © 2013 Springer Science+Business Media Dordrecht.

Capillary response to skeletal muscle contraction: evidence that redundancy between vasodilators is physiologically relevant during active hyperaemia.

Science.gov (United States)

Lamb, Iain R; Novielli, Nicole M; Murrant, Coral L

2018-04-15

The current theory behind matching blood flow to metabolic demand of skeletal muscle suggests redundant interactions between metabolic vasodilators. Capillaries play an important role in blood flow control given their ability to respond to muscle contraction by causing conducted vasodilatation in upstream arterioles that control their perfusion. We sought to determine whether redundancies occur between vasodilators at the level of the capillary by stimulating the capillaries with muscle contraction and vasodilators relevant to muscle contraction. We identified redundancies between potassium and both adenosine and nitric oxide, between nitric oxide and potassium, and between adenosine and both potassium and nitric oxide. During muscle contraction, we demonstrate redundancies between potassium and nitric oxide as well as between potassium and adenosine. Our data show that redundancy is physiologically relevant and involved in the coordination of the vasodilator response during muscle contraction at the level of the capillaries. We sought to determine if redundancy between vasodilators is physiologically relevant during active hyperaemia. As inhibitory interactions between vasodilators are indicative of redundancy, we tested whether vasodilators implicated in mediating active hyperaemia (potassium (K + ), adenosine (ADO) and nitric oxide (NO)) inhibit one another's vasodilatory effects through direct application of pharmacological agents and during muscle contraction. Using the hamster cremaster muscle and intravital microscopy, we locally stimulated capillaries with one vasodilator in the absence and the presence of a second vasodilator (10 -7 m S-nitroso-N-acetylpenicillamine (SNAP), 10 -7 m ADO, 10 mm KCl) applied sequentially and simultaneously, and observed the response in the associated upstream 4A arteriole controlling the perfusion of the stimulated capillary. We found that KCl significantly attenuated SNAP- and ADO-induced vasodilatations by ∼49.7% and �

Geometry-induced phase transition in fluids: Capillary prewetting

OpenAIRE

Yatsyshin, Petr; Savva, Nikos; Kalliadasis, Serafim

2013-01-01

We report a new first-order phase transition preceding capillary condensation and corresponding to the discontinuous formation of a curved liquid meniscus. Using a mean-field microscopic approach based on the density functional theory we compute the complete phase diagram of a prototypical two-dimensional system exhibiting capillary condensation, namely that of a fluid with long-ranged dispersion intermolecular forces which is spatially confined by a substrate forming a semi-infinite rectangu...

Capillary filling under electro-osmotic effects in the presence of electromagneto-hydrodynamic effects

Science.gov (United States)

Desai, Nikhil; Ghosh, Uddipta; Chakraborty, Suman

2014-06-01

We report various regimes of capillary filling dynamics under electromagneto-hydrodynamic interactions, in the presence of electrical double layer effects. Our chosen configuration considers an axial electric field and transverse magnetic field acting on an electrolyte. We demonstrate that for positive interfacial potential, the movement of the capillary front resembles capillary rise in a vertical channel under the action of gravity. We also evaluate the time taken by the capillary front to reach the final equilibrium position for positive interfacial potential and show that the presence of a transverse magnetic field delays the time of travel of the liquid front, thereby sustaining the capillary motion for a longer time. Our scaling estimates reveal that the initial linear regime starts, as well as ends, much earlier in the presence of electrical and magnetic body forces, as compared to the corresponding transients observed under pure surface tension driven flow. We further obtain a long time solution for the capillary imbibition for positive interfacial potential, and derive a scaling estimate of the capillary stopping time as a function of the applied magnetic field and an intrinsic length scale delineating electromechanical influences of the electrical double layer. Our findings are likely to offer alternative strategies of controlling dynamical features of capillary imbibition, by modulating the interplay between electromagnetic interactions, electrical double layer phenomena, and hydrodynamics over interfacial scales.

Transport of volatile organic compounds across the capillary fringe

Science.gov (United States)

McCarthy, Kathleen A.; Johnson, Richard L.

1993-01-01

Physical experiments were conducted to investigate the transport of a dissolved volatile organic compound (trichloroethylene, TCE) from shallow groundwater to the unsaturated zone under a variety of conditions including changes in the soil moisture profile and water table position. Experimental data indicated that at moderate groundwater velocities (0.1 m/d), vertical mechanical dispersion was negligible and molecular diffusion was the dominant vertical transport mechanism. Under these conditions, TCE concentrations decreased nearly 3 orders of magnitude across the capillary fringe and soil gas concentrations remained low relative to those of underlying groundwater. Data collected during a water table drop showed a short-term increase in concentrations throughout most of the unsaturated zone, but these concentrations quickly declined and approached initial values after the water table was returned to its original level. In the deep part of the unsaturated zone, the water table drop resulted in a long-term decrease in concentrations, illustrating the effects of hysteresis in the soil moisture profile. A two-dimensional random walk advection-diffusion model was developed to simulate the experimental conditions, and numerical simulations agreed well with experimental data. A simpler, one-dimensional finite-difference diffusion-dispersion model was also developed. One-dimensional simulations based on molecular diffusion also agreed well with experimental data. Simulations which incorporated mechanical dispersion tended to overestimate flux across the capillary fringe. Good agreement between the one- and two-dimensional models suggested that a simple, one-dimensional approximation of vertical transport across the capillary fringe can be useful when conditions are appropriate.

Gas-filled capillaries for plasma-based accelerators

International Nuclear Information System (INIS)

Filippi, F; Anania, M P; Brentegani, E; Biagioni, A; Chiadroni, E; Ferrario, M; Pompili, R; Romeo, S; Cianchi, A; Zigler, A

2017-01-01

Plasma Wakefield Accelerators are based on the excitation of large amplitude plasma waves excited by either a laser or a particle driver beam. The amplitude of the waves, as well as their spatial dimensions and the consequent accelerating gradient depend strongly on the background electron density along the path of the accelerated particles. The process needs stable and reliable plasma sources, whose density profile must be controlled and properly engineered to ensure the appropriate accelerating mechanism. Plasma confinement inside gas filled capillaries have been studied in the past since this technique allows to control the evolution of the plasma, ensuring a stable and repeatable plasma density distribution during the interaction with the drivers. Moreover, in a gas filled capillary plasma can be pre-ionized by a current discharge to avoid ionization losses. Different capillary geometries have been studied to allow the proper temporal and spatial evolution of the plasma along the acceleration length. Results of this analysis obtained by varying the length and the number of gas inlets will be presented. (paper)

Gas-filled capillaries for plasma-based accelerators

Science.gov (United States)

Filippi, F.; Anania, M. P.; Brentegani, E.; Biagioni, A.; Cianchi, A.; Chiadroni, E.; Ferrario, M.; Pompili, R.; Romeo, S.; Zigler, A.

2017-07-01

Plasma Wakefield Accelerators are based on the excitation of large amplitude plasma waves excited by either a laser or a particle driver beam. The amplitude of the waves, as well as their spatial dimensions and the consequent accelerating gradient depend strongly on the background electron density along the path of the accelerated particles. The process needs stable and reliable plasma sources, whose density profile must be controlled and properly engineered to ensure the appropriate accelerating mechanism. Plasma confinement inside gas filled capillaries have been studied in the past since this technique allows to control the evolution of the plasma, ensuring a stable and repeatable plasma density distribution during the interaction with the drivers. Moreover, in a gas filled capillary plasma can be pre-ionized by a current discharge to avoid ionization losses. Different capillary geometries have been studied to allow the proper temporal and spatial evolution of the plasma along the acceleration length. Results of this analysis obtained by varying the length and the number of gas inlets will be presented.

Ultrastructural analyses of blood capillaries of ovary of 20-days albino rats foetus under their irradiation in different periods of embryogenesis

International Nuclear Information System (INIS)

Ablekovskaya, O.N.; Amvros'ev, A.P.

1999-01-01

The character and direction of structural transformations of blood capillaries of micro circulatory channel of 20-days white rat foetus in normal conditions and after single external 0,5 Gy dose irradiation by 10 and 14 days of embryogenesis were examined. Electron-microscopical, stereo logical and statistical analyses were used. The peculiarities of reactions of hemo capillaries and their cell structure to gamma-rays action in embryogenesis were revealed. It was shown the increase of diameters of capillaries, extension of section area of cytoplasm of endotheliocytes, diminution the size of nuclei of these cells. Polyploid endotheliocytes were found in the experimental conditions. Prenatal acute irradiation in low doses leaded to reduction of the number of microvessels and mitochondria in cytoplasm of cells of blood capillaries in ovary of rat foetus. These results revealed that low dose ionizing radiation changed the morphological expression of important synthetic, transport and energy processes in capillary cells of ovary in fetal period of ontogenesis

Multiple-capillary measurement of RBC speed, flux, and density with optical coherence tomography.

Science.gov (United States)

Lee, Jonghwan; Wu, Weicheng; Lesage, Frederic; Boas, David A

2013-11-01

As capillaries exhibit heterogeneous and fluctuating dynamics even during baseline, a technique measuring red blood cell (RBC) speed and flux over many capillaries at the same time is needed. Here, we report that optical coherence tomography can capture individual RBC passage simultaneously over many capillaries located at different depths. Further, we demonstrate the ability to quantify RBC speed, flux, and linear density. This technique will provide a means to monitor microvascular flow dynamics over many capillaries at different depths at the same time.

Transmission properties of C60 ions through micro- and nano-capillaries

International Nuclear Information System (INIS)

Tsuchida, Hidetsugu; Majima, Takuya; Tomita, Shigeo; Sasa, Kimikazu; Narumi, Kazumasa; Saitoh, Yuichi; Chiba, Atsuya; Yamada, Keisuke; Hirata, Koichi; Shibata, Hiromi; Itoh, Akio

2013-01-01

We apply the capillary beam-focusing method for the C 60 fullerene projectiles in the velocity range between 0.14 and 0.2 a.u. We study the C 60 transmission properties through two different types of capillaries: (1) borosilicate glass microcapillary with an outlet diameter of 5.5 μm, and (2) Al 2 O 3 multi-capillary foil with a pore size of about 70 nm and a high aspect ratio of about 750. We measured the transmitted particle composition by using the electrostatic deflection method combined with the microchannel plate imaging technique. For the experiments with the single microcapillary, the main transmission component is found to be primary C 60 beams that are focused in the area equal to the capillary outlet diameter. Minor components are charge-exchanged C 60 ions and charged or neutral fragments (fullerene-like C 60-2m and small C n particles), and their fractions decrease with decreasing the projectile velocity. It is concluded that the C 60 transmission fraction is considerably high for both types of the capillaries in the present velocity range

Two-dimensional capillary origami

Energy Technology Data Exchange (ETDEWEB)

Brubaker, N.D., E-mail: nbrubaker@math.arizona.edu; Lega, J., E-mail: lega@math.arizona.edu

2016-01-08

We describe a global approach to the problem of capillary origami that captures all unfolded equilibrium configurations in the two-dimensional setting where the drop is not required to fully wet the flexible plate. We provide bifurcation diagrams showing the level of encapsulation of each equilibrium configuration as a function of the volume of liquid that it contains, as well as plots representing the energy of each equilibrium branch. These diagrams indicate at what volume level the liquid drop ceases to be attached to the endpoints of the plate, which depends on the value of the contact angle. As in the case of pinned contact points, three different parameter regimes are identified, one of which predicts instantaneous encapsulation for small initial volumes of liquid. - Highlights: • Full solution set of the two-dimensional capillary origami problem. • Fluid does not necessarily wet the entire plate. • Global energy approach provides exact differential equations satisfied by minimizers. • Bifurcation diagrams highlight three different regimes. • Conditions for spontaneous encapsulation are identified.

Two-dimensional capillary origami

International Nuclear Information System (INIS)

Brubaker, N.D.; Lega, J.

2016-01-01

We describe a global approach to the problem of capillary origami that captures all unfolded equilibrium configurations in the two-dimensional setting where the drop is not required to fully wet the flexible plate. We provide bifurcation diagrams showing the level of encapsulation of each equilibrium configuration as a function of the volume of liquid that it contains, as well as plots representing the energy of each equilibrium branch. These diagrams indicate at what volume level the liquid drop ceases to be attached to the endpoints of the plate, which depends on the value of the contact angle. As in the case of pinned contact points, three different parameter regimes are identified, one of which predicts instantaneous encapsulation for small initial volumes of liquid. - Highlights: • Full solution set of the two-dimensional capillary origami problem. • Fluid does not necessarily wet the entire plate. • Global energy approach provides exact differential equations satisfied by minimizers. • Bifurcation diagrams highlight three different regimes. • Conditions for spontaneous encapsulation are identified.

Recent advances in the preparation and application of monolithic capillary columns in separation science

Energy Technology Data Exchange (ETDEWEB)

Hong, Tingting; Yang, Xi; Xu, Yujing [Department of Analytical Chemistry, China Pharmaceutical University, Nanjing, 210009 (China); Key Laboratory of Drug Quality Control and Pharmacovigilance, Ministry of Education, Nanjing, 210009 (China); Ji, Yibing, E-mail: jiyibing@msn.com [Department of Analytical Chemistry, China Pharmaceutical University, Nanjing, 210009 (China); Key Laboratory of Drug Quality Control and Pharmacovigilance, Ministry of Education, Nanjing, 210009 (China)

2016-08-10

Novel column technologies involving various materials and efficient reactions have been investigated for the fabrication of monolithic capillary columns in the field of analytical chemistry. In addition to the development of these miniaturized systems, a variety of microscale separation applications have achieved noteworthy results, providing a stepping stone for new types of chromatographic columns with improved efficiency and selectivity. Three novel strategies for the preparation of capillary monoliths, including ionic liquid-based approaches, nanoparticle-based approaches and “click chemistry”, are highlighted in this review. Furthermore, we present the employment of state-of-the-art capillary monolithic stationary phases for enantioseparation, solid-phase microextraction, mixed-mode separation and immobilized enzyme reactors. The review concludes with recommendations for future studies and improvements in this field of research. - Highlights: • Preparation of novel monolithic capillary columns have shown powerful potential in analytical chemistry field. • Various materials including ionic liquids and nanoparticles involved into capillary monolithic micro-devices are concluded. • Click chemistry strategy applied for preparing monolithic capillary columns is reviewed. • Recent strategies utilized in constructing different capillary monoliths for enantiomeric separation are summarized. • Advancement of capillary monoliths for complex samples analysis is comprehensively described.

Recent advances in the preparation and application of monolithic capillary columns in separation science

International Nuclear Information System (INIS)

Hong, Tingting; Yang, Xi; Xu, Yujing; Ji, Yibing

2016-01-01

Novel column technologies involving various materials and efficient reactions have been investigated for the fabrication of monolithic capillary columns in the field of analytical chemistry. In addition to the development of these miniaturized systems, a variety of microscale separation applications have achieved noteworthy results, providing a stepping stone for new types of chromatographic columns with improved efficiency and selectivity. Three novel strategies for the preparation of capillary monoliths, including ionic liquid-based approaches, nanoparticle-based approaches and “click chemistry”, are highlighted in this review. Furthermore, we present the employment of state-of-the-art capillary monolithic stationary phases for enantioseparation, solid-phase microextraction, mixed-mode separation and immobilized enzyme reactors. The review concludes with recommendations for future studies and improvements in this field of research. - Highlights: • Preparation of novel monolithic capillary columns have shown powerful potential in analytical chemistry field. • Various materials including ionic liquids and nanoparticles involved into capillary monolithic micro-devices are concluded. • Click chemistry strategy applied for preparing monolithic capillary columns is reviewed. • Recent strategies utilized in constructing different capillary monoliths for enantiomeric separation are summarized. • Advancement of capillary monoliths for complex samples analysis is comprehensively described.

Capillary-metric surveillance of the personnel professionally exposed to ionizing radiations

International Nuclear Information System (INIS)

Perdereau, B.; Brixy, F.; Cosset, J.M.

1997-01-01

The aim of this work was to ensure the surveillance of low irradiation doses cumulated at the level of fingers by means of a sensible, reliable and low-cost method. The skin capillary network represents an indicator of high sensibility for alteration caused by ionizing radiations. The capillary-metry is a method which consists in exploiting numerically the parameters deduced from capillary-scopic observation. A stereo-microscope of low magnifying power and large frontal distance permits a tridimensional visualisation of capillary loops after trans-illumination of the skin (immersion oil). The photographic and numerical recording on diskettes is achieved on the pathological zones of all fingers of both hands. The multi-criteria exploitation (the characteristics of capillaries, their environment and populations) allows their interpretation. Twenty-one subjects were controlled in the frame of a radio-pathological surveillance at Institut Curie de Paris. The case study presenting a confirmed chronic irradiation has evidenced alteration in organisation, in the distribution of capillaries and also a decrease in their number and a diminution of their diameter. Finally, the presence of ecstasies and stenoses is frequent as the presence of desert zones. In conclusion, these alterations, although less spectacularly then the acute irradiation are sufficiently marked to be not confounded with the microvascular chronic anomalies observed in chemists, masons or musicians, as those of current vascular pathology

Critical effect of pore characteristics on capillary infiltration in mesoporous films.

Science.gov (United States)

Ceratti, D R; Faustini, M; Sinturel, C; Vayer, M; Dahirel, V; Jardat, M; Grosso, D

2015-03-12

Capillary phenomena governing the mass-transport (capillary filling, condensation/evaporation) has been experimentally investigated in around 20 different silica thin films exhibiting various porosities with pores dimension ranging from 2 to 200 nm. Films have been prepared by sol-gel chemistry combined with soft-templating approaches and controlled dip coating process. Environmental ellipsometric porosimetry combined with electronic microscopy were used to assess the porosity characteristics. Investigation of lateral capillary filling was performed by following the natural infiltration of water and ionic liquids at the edge of a sessile drop in open air or underneath a PDMS cover. The Washburn model was applied to the displacement of the liquid front within the films to deduce the kinetic constants. The role of the different capillary phenomena were discussed with respect to the porosity characteristics (porosity vol%, pore dimensions and constrictions). We show that correlation between capillary filling rate and pore dimensions is not straightforward. Generally, with a minimum of constrictions, faster filling is observed for larger pores. In the case of mesopores (capillary condensation dynamics, taking place at the meniscus inside the porosity, has to be considered to explain the transport mode. This fundamental study is of interest for applications involving liquids at the interface of mesoporous networks such as nanofluidics, purification, separation, water harvesting or heat transfer.

The Phase Envelope of Multicomponent Mixtures in the Presence of a Capillary Pressure Difference

DEFF Research Database (Denmark)

Sandoval Lemus, Diego Rolando; Yan, Wei; Michelsen, Michael Locht

2016-01-01

for test mixtures with wide ranges of compositions at different capillary radii and vapor fractions. The calculation results show that the phase envelope changes everywhere except at the critical point. The bubble point and the lower branch of the dew point show a decrease in the saturation pressure......, whereas the upper branch of the dew point shows an increase. The cricondentherm is shifted to a higher temperature. We also presented a mathematical analysis of the phase envelope shift due to capillary pressure based on linear approximations. The resulting linear approximation equations can predict...... the magnitude of shift, and the approximation is close for the change in the bubble point pressure....

YSZ-Reinforced Alumina Multi-Channel Capillary Membranes for Micro-Filtration

Directory of Open Access Journals (Sweden)

Bo Wang

2015-12-01

Full Text Available The combined phase-inversion and sintering method not only produces ceramic hollow fibre membranes with much lower fabrication costs than conventional methods, but these membranes can also be designed to have greatly reduced transport resistances for filtration processes. The bottleneck of this technique is the weak mechanical property of the fibres, due to the small dimensions and the brittle nature of the ceramic materials. In this study, yttrium stabilised zirconia (YSZ reinforced alumina seven-channel capillary microfiltration membranes were prepared with a pore size of ~230 nm and their mechanical property and permeation characteristics were studied. It is found that the addition of YSZ can effectively enhance the mechanical property of the membrane and also increase pure water permeation flux. The Al2O3-YSZ seven-channel capillary membranes could reach a fracture load of 23.4 N and a bending extension of 0.54 mm when being tested with a 6 cm span, to meet the requirements for most industrial microfiltration applications.

YSZ-Reinforced Alumina Multi-Channel Capillary Membranes for Micro-Filtration.

Science.gov (United States)

Wang, Bo; Lee, Melanie; Li, Kang

2015-12-30

The combined phase-inversion and sintering method not only produces ceramic hollow fibre membranes with much lower fabrication costs than conventional methods, but these membranes can also be designed to have greatly reduced transport resistances for filtration processes. The bottleneck of this technique is the weak mechanical property of the fibres, due to the small dimensions and the brittle nature of the ceramic materials. In this study, yttrium stabilised zirconia (YSZ) reinforced alumina seven-channel capillary microfiltration membranes were prepared with a pore size of ~230 nm and their mechanical property and permeation characteristics were studied. It is found that the addition of YSZ can effectively enhance the mechanical property of the membrane and also increase pure water permeation flux. The Al₂O₃-YSZ seven-channel capillary membranes could reach a fracture load of 23.4 N and a bending extension of 0.54 mm when being tested with a 6 cm span, to meet the requirements for most industrial microfiltration applications.

Thermal analysis of reservoir structure versus capillary pumped loop

International Nuclear Information System (INIS)

Lin Hungwen; Lin Weikeng

2009-01-01

Capillary pumped loop (CPL) was already used in man-made satellites and space aircrafts with proven heat control technology. However, small-sized CPL had not yet made a breakthrough application in electronic components owing to poor heat-absorption capacity of evaporator structure. Hence, a small-scale CPL was designed for server in this research. The evaporator was designed with a circular groove and embedded with a high density polyethylene (HDPE) as a capillary structure to absorb working fluid. The influence of reservoir upon thermal resistance was also analyzed. The experimental results showed that, under a filling level of 72%, CPL with optimized design could remove 110 W energy while maintaining its temperature at 80 deg. C. Comparison of CPL with/without reservoir, the loop thermal resistance R th,loop was reduced by 0.14 deg. C/W and was able to increase the stability of CPL, too, the results confirmed that reservoir could enhance CPL performance and this technology will probably find application in electronics cooling for electronic devices

Capillary filling of miniaturized sources for electrospray mass spectrometry

International Nuclear Information System (INIS)

Arscott, Steve; Gaudet, Matthieu; Brinkmann, Martin; Ashcroft, Alison E; Blossey, Ralf

2006-01-01

Capillary slot-based emitter tips are a novel tool for use in electrospray ionization-mass spectrometry of large biomolecules. We have performed a combined theoretical and experimental study of capillary filling in micron-sized slots with the aim of developing a rational design procedure for miniaturized electrospray sources, ultimately enabling the integration of ESI into laboratory-on-a-chip devices

Soft x-ray amplification in an ablative capillary discharge

International Nuclear Information System (INIS)

Kwek, K.H.; Low, K.S.; Tan, C.A.; Lim, C.S.

1999-01-01

Soft x-ray amplification in CVI 18.2 nm line is observed in an ablative UHMW-PE capillary discharge. The gain coefficient is measured to be 1.9 cm -1 . The electron density is about 2 x 10 19 cm -3 . This indicates that capillary discharge pumping device can be a source for a compact soft x-ray laser. (author)

The application of capillary microsampling in GLP toxicology studies.

Science.gov (United States)

Verhaeghe, Tom; Dillen, Lieve; Stieltjes, Hans; Zwart, Loeckie de; Feyen, Bianca; Diels, Luc; Vroman, Ann; Timmerman, Philip

2017-04-01

Capillary microsampling (CMS) to collect microplasma volumes is gradually replacing traditional, larger volume sampling from rats in GLP toxicology studies. About 32 µl of blood is collected with a capillary, processed to plasma and stored in a 10- or 4-µl capillary which is washed out further downstream in the laboratory. CMS has been standardized with respect to materials, assay validation experiments and application for sample analysis. The implementation of CMS has resulted in blood volume reductions in the rat from 300 to 32 µl per time point and the elimination of toxicokinetic satellite groups in the majority of the rat GLP toxicology studies. The technique has been successfully applied in 26 GLP studies for 12 different projects thus far.

Fabrication and modeling of narrow capillaries for vacuum system gas inlets

DEFF Research Database (Denmark)

Quaade, Ulrich; Jensen, Søren; Hansen, Ole

2005-01-01

Micrometer-sized cylindrical capillaries with well-controlled dimensions are fabricated using deep reactive ion etching. The flow through the capillaries is experimentally characterized for varying pressures, temperatures, and diameters. For the parameters used, it is shown that the Knudsen numbe...... is in the intermediate flow regime, and Knudsen's expression for the flow fit the data well. The flow properties of the capillaries make them ideal for introducing gas into vacuum systems and in particular mass spectrometers. ©2005 American Institute of Physics...

Thermally excited capillary waves at vapor/liquid interfaces of water-alcohol mixtures

International Nuclear Information System (INIS)

Vaknin, David; Bu Wei; Sung, Jaeho; Jeon, Yoonnam; Kim, Doseok

2009-01-01

The density profiles of liquid/vapor interfaces of water-alcohol (methanol, ethanol and propanol) mixtures were studied by surface-sensitive synchrotron x-ray scattering techniques. X-ray reflectivity and diffuse scattering measurements, from the pure and mixed liquids, were analyzed in the framework of capillary wave theory to address the characteristic length scales of the intrinsic roughness and the shortest capillary wavelength (alternatively, the upper wavevector cutoff in capillary wave theory). Our results establish that the intrinsic roughness is dominated by average interatomic distances. The extracted effective upper wavevector cutoff indicates capillary wave theory breaks down at distances of the order of bulk correlation lengths.

Effect of surfactant on kinetics of thinning of capillary bridges

Science.gov (United States)

Nowak, Emilia; Kovalchuk, Nina; Simmons, Mark

2015-11-01

Kinetics of thinning of capillary bridges is of great scientific and industrial interest being of vital importance for example in various emulsification and microfluidic processes. It is well known that the rate of bridge thinning is proportional to the interfacial tension. Therefore it is expected that the process should slow down by addition of surfactant. The kinetics of capillary bridges in the presence of surfactant was studied by the dripping of liquid from a capillary tip under conditions of nearly zero flow rate (We personal care products. The viscosity, surfactant activity and adsorption kinetics have been controlled by addition of glycerol and sodium chloride. The study has shown that the kinetics of capillary bridges are determined by dynamic surface tension rather than by its equilibrium value. In particular, the kinetics of the bridge thinning for the 0.1 g L-1 aqueous SLES solution is practically the same as that of pure water despite twice lower equilibrium surface tension. EPSRC Programme Grant, MEMPHIS, EP/K0039761/1.

Solid density, low temperature plasma formation in a capillary discharge

International Nuclear Information System (INIS)

Kania, D.R.; Jones, L.A.; Maestas, M.D.; Shepherd, R.L.

1987-01-01

This work discusses the ability of the authors to produce solid density, low temperature plasmas in polyurethane capillary discharges. The initial capillary diameter is 20 μm. The plasma is produced by discharging a one Ohm parallel plate waterline and Marx generator system through the capillary. A peak current of 340 kA in 300 ns heats the inner wall of the capillary, and the plasma expands into the surrounding material. The authors studied the evolution of the discharge using current and voltage probes, axial and radial streak photography, axial x-ray diode array and schlieren photography, and have estimated the peak temperature of the discharge to be approximately 10 eV and the density to be near 10/sup 23/cm/sup -3/. This indicates that the plasma may approach the strongly coupled regime. They discuss their interpretation of the data and compare their results with theoretical models of the plasma dynamics

Time effectiveness of capillary effect improvement of ramie fabrics processed by RF glow discharging

International Nuclear Information System (INIS)

Wang Zhiwen; Wei Weixing; He Yanhe; Zhao Yuanqing; Pan Liyiji; Li Xuemei; Shi Shaodui; Li Guangxin

2010-01-01

The time effectiveness of capillary effect improvement of ramie fabrics processed by RF glow discharging was studied. The ramie fabrics were processed in fulfilling with different gas (O 2 , N 2 , Ar) by different parameters (such as pressure,power and time) plasma. The capillary effect of the ramie fabrics processed by RF glow discharging was tested at different time. The results indicate that the capillary effect of ramie fabrics processed by RF glow discharging has been improved, the improvement of the capillary effect firstly decrease rapidly, then slowly, and become stable after 15 day, it indicate that improvement of the ramie fabrics capillary has good time effectiveness, and the plasma parameter for the best capillary effect improvement of ramie fabric is 100 W and 40 Pa processed 20 min by oxygen plasma. (authors)

Polycythemia, capillary rarefaction, and focal glomerulosclerosis in two adolescents born extremely low birth weight and premature.

Science.gov (United States)

Asada, Nariaki; Tsukahara, Takanori; Furuhata, Megumi; Matsuoka, Daisuke; Noda, Shunsuke; Naganuma, Kuniaki; Hashiguchi, Akinori; Awazu, Midori

2017-07-01

Low birthweight infants have a reduced number of nephrons and are at high risk of chronic kidney disease. Preterm birth and/or intrauterine growth restriction (IUGR) may also affect peritubular capillary development, as has been shown in other organs. We report two patients with a history of preterm birth and extremely low birthweight who showed polycythemia and renal capillary rarefaction. Patient 1 and 2, born at 25 weeks of gestation with a birthweight of 728 and 466 g, showed mild proteinuria at age 8 and 6 years, respectively. In addition to increasing proteinuria, hemoglobin levels became elevated towards adolescence and their serum erythropoietin (EPO) was high despite polycythemia. Light microscopic examination of renal biopsy specimens showed glomerular hypertrophy, focal segmental glomerulosclerosis, and only mild tubulointerstitial fibrosis. A decrease in the immunohistochemical staining of CD31 and CD34 endothelial cells in renal biopsy specimens was consistent with peritubular capillary rarefaction. Since kidney function was almost normal and fibrosis was not severe, we consider that the capillary rarefaction and polycythemia associated with elevated EPO levels were largely attributable to preterm birth and/or IUGR.

Hysteretic capillary condensation in a porous material

International Nuclear Information System (INIS)

Lilly, M.P.; Hallock, R.B.

1995-01-01

The authors report on the behavior of hysteresis subloops in the capillary condensation of 4 He in the porous material Nuclepore. For hysteretic systems composed of many independent elements, the Preisach model may be used to predict the behavior of the resulting hysteresis. One prediction is that subloops with common chemical potential endpoints will be congruent. The observations of such subloops show that the prediction of congruence fails for this capillary condensation system. To understand deviations from Preisach behavior the authors modify the model to account for intersections among the pores. The modified model is in close agreement with the experimental results

Laser–capillary interaction for the EXIN project

Energy Technology Data Exchange (ETDEWEB)

Bisesto, F.G., E-mail: fabrizio.giuseppe.bisesto@lnf.infn.it [INFN-LNF, Via Enrico Fermi 40, 00044 Frascati (Italy); Sapienza – University of Rome, P.le Aldo Moro, 2, 00185 Rome (Italy); Anania, M.P. [INFN-LNF, Via Enrico Fermi 40, 00044 Frascati (Italy); Bacci, A.L. [INFN – Milano, Via Celoria 16, 20133 Milan (Italy); Bellaveglia, M.; Chiadroni, E. [INFN-LNF, Via Enrico Fermi 40, 00044 Frascati (Italy); Cianchi, A. [INFN-LNF, Via Enrico Fermi 40, 00044 Frascati (Italy); Universit degli studi di Roma Tor Vergata, Via di Tor Vergata, Rome (Italy); Curcio, A. [INFN-LNF, Via Enrico Fermi 40, 00044 Frascati (Italy); Sapienza – University of Rome, P.le Aldo Moro, 2, 00185 Rome (Italy); Di Giovenale, D.; Di Pirro, G.; Ferrario, M.; Galletti, M.; Gallo, A.; Ghigo, A. [INFN-LNF, Via Enrico Fermi 40, 00044 Frascati (Italy); Marocchino, A.; Mostacci, A.; Petrarca, M. [Sapienza – University of Rome, P.le Aldo Moro, 2, 00185 Rome (Italy); INFN – Roma1, P.le Aldo Moro, 2, 00185 Rome (Italy); Pompili, R. [INFN-LNF, Via Enrico Fermi 40, 00044 Frascati (Italy); Rossi, A.R.; Serafini, L. [INFN – Milano, Via Celoria 16, 20133 Milan (Italy); Vaccarezza, C. [INFN-LNF, Via Enrico Fermi 40, 00044 Frascati (Italy)

2016-09-01

The EXIN project is under development within the SPARC-LAB facility of the National Laboratory of Frascati (LNF-INFN). This project aims to accelerate pre-existing electron bunches with high brightness by exploiting the wakefield plasma acceleration technique, while preserving the initial brightness. The wakefield is excited inside a dielectric capillary by high intensity laser pulses produced by the FLAME laser interacting with a gas. In this work, we present numerical simulations in order to optimize energy coupling between our laser with super-Gaussian transverse profile and a dielectric capillary. Moreover, an overview of the experimental layout will be given.

Pulmonary capillary recruitment in response to hypoxia in healthy humans: a possible role for hypoxic pulmonary venoconstriction?

DEFF Research Database (Denmark)

Taylor, Bryan J; Kjaergaard, Jesper; Snyder, Eric M

2011-01-01

We examined mechanisms by which hypoxia may elicit pulmonary capillary recruitment in humans. On separate occasions, twenty-five healthy adults underwent exposure to intravenous saline infusion (30 ml/kg ∼ 15 min) or 17-h normobaric hypoxia ( [FIO2 = 12.5%). Cardiac output (Q) and pulmonary...... capillary blood volume (Vc) were measured before and after saline infusion and hypoxic-exposure by a rebreathing method. Pulmonary artery systolic pressure (sPpa) and left ventricular (LV) diastolic function were assessed before and after hypoxic-exposure via echocardiography. Saline infusion increased Q......Ppa and LV diastolic function. In conclusion, hypoxia-induced pulmonary capillary recruitment in humans is only partly accounted for by changes in Q, sPpa and LV diastolic function. We speculate that hypoxic pulmonary venoconstriction may play a role in such recruitment....

Capillary thinning of polymeric filaments

DEFF Research Database (Denmark)

Kolte, Mette Irene; Szabo, Peter

1999-01-01

The capillary thinning of filaments of a Newtonian polybutene fluid and a viscoelastic polyisobutylene solution are analyzed experimentally and by means of numerical simulation. The experimental procedure is as follows. Initially, a liquid sample is placed between two cylindrical plates. Then, th...

Capillary-Patterns for Biometric Authentication

NARCIS (Netherlands)

Paloma Benedicto, J.; Bruekers, A.A.M.; Presura, C.N.; Garcia Molina, G.

2007-01-01

In this report, we present a method using the capillary structuresunder the "distal interphalangeal joint" (DIP joint), which is located between the second and third (distal) phalanges of the finger, for achieving secure biometric authentication. Images of the DIPjoint are acquired using a

Effects of altitude and exercise on pulmonary capillary integrity: evidence for subclinical high-altitude pulmonary edema.

Science.gov (United States)

Eldridge, Marlowe W; Braun, Ruedi K; Yoneda, Ken Y; Walby, William F

2006-03-01

Strenuous exercise may be a significant contributing factor for development of high-altitude pulmonary edema, particularly at low or moderate altitudes. Thus we investigated the effects of heavy cycle ergometer exercise (90% maximal effort) under hypoxic conditions in which the combined effects of a marked increase in pulmonary blood flow and nonuniform hypoxic pulmonary vasoconstriction could add significantly to augment the mechanical stress on the pulmonary microcirculation. We postulated that intense exercise at altitude would result in an augmented permeability edema. We recruited eight endurance athletes and examined their bronchoalveolar lavage fluid (BALF) for red blood cells (RBCs), protein, inflammatory cells, and soluble mediators at 2 and 26 h after intense exercise under normoxic and hypoxic conditions. After heavy exercise, under all conditions, the athletes developed a permeability edema with high BALF RBC and protein concentrations in the absence of inflammation. We found that exercise at altitude (3,810 m) caused significantly greater leakage of RBCs [9.2 (SD 3.1)x10(4) cells/ml] into the alveolar space than that seen with normoxic exercise [5.4 (SD 1.2)x10(4) cells/ml]. At altitude, the 26-h postexercise BALF revealed significantly higher RBC and protein concentrations, suggesting an ongoing capillary leak. Interestingly, the BALF profiles following exercise at altitude are similar to that of early high-altitude pulmonary edema. These findings suggest that pulmonary capillary disruption occurs with intense exercise in healthy humans and that hypoxia augments the mechanical stresses on the pulmonary microcirculation.

Investigation of pressure drop in capillary tube for mixed refrigerant Joule-Thomson cryocooler

International Nuclear Information System (INIS)

Ardhapurkar, P. M.; Sridharan, Arunkumar; Atrey, M. D.

2014-01-01

A capillary tube is commonly used in small capacity refrigeration and air-conditioning systems. It is also a preferred expansion device in mixed refrigerant Joule-Thomson (MR J-T) cryocoolers, since it is inexpensive and simple in configuration. However, the flow inside a capillary tube is complex, since flashing process that occurs in case of refrigeration and air-conditioning systems is metastable. A mixture of refrigerants such as nitrogen, methane, ethane, propane and iso-butane expands below its inversion temperature in the capillary tube of MR J-T cryocooler and reaches cryogenic temperature. The mass flow rate of refrigerant mixture circulating through capillary tube depends on the pressure difference across it. There are many empirical correlations which predict pressure drop across the capillary tube. However, they have not been tested for refrigerant mixtures and for operating conditions of the cryocooler. The present paper assesses the existing empirical correlations for predicting overall pressure drop across the capillary tube for the MR J-T cryocooler. The empirical correlations refer to homogeneous as well as separated flow models. Experiments are carried out to measure the overall pressure drop across the capillary tube for the cooler. Three different compositions of refrigerant mixture are used to study the pressure drop variations. The predicted overall pressure drop across the capillary tube is compared with the experimentally obtained value. The predictions obtained using homogeneous model show better match with the experimental results compared to separated flow models

The profile of a capillary liquid bridge between solid surfaces

NARCIS (Netherlands)

van Honschoten, J.W.; Tas, Niels Roelof; Elwenspoek, Michael Curt

2010-01-01

Scanning force microscopy, such as atomic force microscopy (AFM) is complicated by the capillary force of a water meniscus formed in air between the probe tip and the sample. This small liquid bridge between the hydrophilic sample and the sharp AFM tip can be formed by capillary condensation from

On the capillary restriction in start-up regimes of liquid metal evaporation from capillary-porous surfaces

International Nuclear Information System (INIS)

Prosvetov, V.V.

1979-01-01

Evaporation of liquid metals from capillary-porous structures is one of the most effective methods of surface cooling, to which essential heat quantity is delivered at high temperatures. The paper deals with heat flux limitation, caused by incapability of core capillary forces to overcome pressure differential in heat carrier circulation shape in such evaporation regimes, when average length of free path of vapour molecule exceeds core cell size. Suggested are theoretical correlations for determination of critical heat flux density and temperature of liquid surface in starting regimes of liquid metal evaporation from rectangular slots and compound cores with screens made of foil with round perforations. The catculative and experimental values of critical heat flux density in starting regimes of sodium evaporation from rectangular slots satisfactorily agree with each other

Proliferative activity of endotheliocytes of growing capillaries of the rabbit cornea

International Nuclear Information System (INIS)

Gurina, O.Yu.; Mamontov, S.G.; Banin, V.V.

1987-01-01

The authors studied the intensity of DNA synthesis by cells of newly formed capillaries, growing in the rabbit cornea, after infliction of a silver nitrate burn and local application of colchicine. The intensity of capillary growth was investigated during stimulation and a combination of the burn with colchicine. Changes in activity of DNA synthesis by the endotheliocytes of newly formed capillaries during exposure throughout growth were also investigated. The intensity of cell proliferation was studied by measuring the incorporation of tritium-labelled thymidine into the endotheoiocyte nuclei

Field-portable Capillary Electrophoresis Instrument with Conductivity Detection

International Nuclear Information System (INIS)

Zhang, H F; Liu, X W; Wang, W; Wang, X L; Tian, L

2006-01-01

In this paper a novel capillary electrophoresis chip (CEC) is presented with integrated platinum electrodes and simplified conductivity detector. CEC is fabricated by the method of mechanical modification with probe on organic glass. Capillary electrophoresis chip can rapidly completed ion separation by simulation of concentration distribution and zone-broadening. Detection circuit is simple which can detect pA order current. This system has those advantages such as small volume, low power consumption and linearity, and well suit for field analysis

A capillary-based perfusion phantom for simulation of brain perfusion for MRI

International Nuclear Information System (INIS)

Maciak, A.; Kronfeld, A.; Mueller-Forell, W.; Wille, C.; Kempski, O.; Stoeter, P.

2010-01-01

Purpose: The measurement of the CBF is a non-standardized procedure and there are no reliable gold standards. This abstract shows a capillary-based perfusion-phantom for CE-DSC-MRI. It has equivalent flow properties to those within the tissue capillary system of the human brain and allows the validation of the Siemens Perfusion (MR) software. Materials and Methods: The perfusion phantom consists of a dialyzer for the simulation of the capillary system, a feeding tube for simulation of the AIF and a pulsatile pump for simulation of the heart. Using this perfusion phantom, the exact determination of the gold standard CBF due to the well-known geometry of the phantom is easy. It was validated based on different perfusion measurements. These measurements were investigated with standard software (Siemens Perfusion MR). The software determined the CBF within the capillary system. Based on this CBF, a comparison to the gold standard was made with several different flow speeds. After AIF selection, a total of 726 CBF data points were automatically extracted by the software. Results: This results in a comparison of the gold standard CBF to these 726 CBF values. Therefore, a reproducible and reliable deviation estimation between gold standard CBF and measured CBF using the software was computed. It can be shown that the deviation between gold standard and software-based evaluation ranges between 1 and 31 %. Conclusion: There is no significance for any correlation between flow speed and amount of deviation. The mean measured CBF is 11.4 % higher than the gold standard CBF (p-value < 0.001). Using this kind of perfusion-phantom, the validation of different software systems allows reliable conclusions about their quality. (orig.)

Statistical intensity variation analysis for rapid volumetric imaging of capillary network flux.

Science.gov (United States)

Lee, Jonghwan; Jiang, James Y; Wu, Weicheng; Lesage, Frederic; Boas, David A

2014-04-01

We present a novel optical coherence tomography (OCT)-based technique for rapid volumetric imaging of red blood cell (RBC) flux in capillary networks. Previously we reported that OCT can capture individual RBC passage within a capillary, where the OCT intensity signal at a voxel fluctuates when an RBC passes the voxel. Based on this finding, we defined a metric of statistical intensity variation (SIV) and validated that the mean SIV is proportional to the RBC flux [RBC/s] through simulations and measurements. From rapidly scanned volume data, we used Hessian matrix analysis to vectorize a segment path of each capillary and estimate its flux from the mean of the SIVs gathered along the path. Repeating this process led to a 3D flux map of the capillary network. The present technique enabled us to trace the RBC flux changes over hundreds of capillaries with a temporal resolution of ~1 s during functional activation.

A Comparison of Capillary and Venous Blood Haematocrits of Pregnant Women in Nigeria: The Impact on Diagnosis and Prevalence of Anaemia in Pregnancy

Directory of Open Access Journals (Sweden)

Cyril Chukwudi Dim

2014-01-01

Full Text Available Background. Volume of red cells in capillary blood varies from that of venous blood. The magnitude of this variation as well as its impact on the diagnosis of anaemia in pregnancy needs to be studied. This study demonstrates the disparity between capillary and venous PCV in pregnancy. Objectives. To determine whether capillary blood PCV (cPCV differed from venous blood PCV (vPCV of normal pregnant women in Enugu, Nigeria, and its effect on diagnosis and prevalence of anaemia. Methods. PCV was estimated using pairs of venous and capillary blood samples from 200 consecutive pregnant women at the Antenatal Clinic of University of Nigeria Teaching Hospital, Enugu, Nigeria. Results. Participants’ cPCV (median=34.0%, IQR=31.0–35.8 was significantly lower than their vPCV (median=34.0%, IQR=32.0–37.0 (Z=-6.85, P<0.001. However, women’s cPCV had strong positive correlation with their vPCV (r=0.883, P<0.001. The prevalence of anaemia among participants using capillary and venous blood was 33.5% (67/200 and 28.0% (56/200, respectively (O.R=1.3 (CI 95%: 0.85, 1.98,  P=0.233. Conclusions. Capillary blood PCV was lower than vPCV among pregnant women in Enugu, Nigeria. Nevertheless, the prevalence of anaemia derived from cPCV did not differ significantly from that of vPCV.

Numerical study of a double-slope solar still coupled with capillary film condenser in south Algeria

International Nuclear Information System (INIS)

Belhadj, Mohamed Mustapha; Bouguettaia, Hamza; Marif, Yacine; Zerrouki, Moussa

2015-01-01

Highlights: • This is a numerical work on solar stills in the desert of Algeria using solar energy. • Solar stills can secure fresh water to low density remote desert agglomerations. • The yield was improved by coupling a solar still with a capillary film condenser. • The distilled water production increases with the reduction in flow feed saline water. • The yield varies conversely with the distance between the two condensing plates. - Abstract: The effect of joining a condensation cell to a single-basin double slope solar still was investigated numerically. Direct solar radiation heated the saline water then evaporated. A fraction of the resulting vapor is condensed on the inner glass cover plate and the rest on the outer metal plate. Solar radiation, ambient temperature and the temperatures at different system components were monitored. The performance of the system was evaluated and compared to that of a conventional solar still under the same meteorological conditions. The proposed prototype functioned perfectly and its daily yield reached 7.15 kg m −2 d −1 . Results show that the productivity of the present system was about 60% higher than that of the conventional and capillary film types. The contributions of the glass cover, metal plate and condenser plate are 43%, 18% and 39% of the total distillate yield respectively. It was noticed that the productivity of the capillary film solar still was sensitive to the mass flow of the feeding water. It was also found that the absorptivity coefficient and the diffusion gap have significant effect on distillate production of the system

In-capillary enrichment, proteolysis and separation using capillary electrophoresis with discontinuous buffers: application on proteins with moderately acidic and basic isoelectric points.

Science.gov (United States)

Nesbitt, Chandra A; Yeung, Ken K-C

2009-01-01

Advances in mass spectrometry and capillary-format separation continue to improve the sensitivity of protein analysis. Of equal importance is the miniaturization of sample pretreatment such as enrichment and proteolysis. In a previous report (Nesbitt et al., Electrophoresis, 2008, 29, 466-474), nanoliter-volume protein enrichment, tryptic digestion, and partial separation was demonstrated in capillary electrophoresis followed by MALDI mass spectral analysis. A discontinuous buffer system, consisting of ammonium (pH 10) and acetate (pH 4), was used to create a pH junction inside the capillary, trapping a protein with a neutral isoelectric point, myoglobin (pI 7.2). Moreover, co-enrichment of myoglobin with trypsin led to an in-capillary digestion. In this paper, the ability of this discontinuous buffer system to perform similar in-capillary sample pretreatment on proteins with moderately acidic and basic pI was studied and reported. Lentil lectin (pI 8.6) and a multi-phosphorylated protein, beta-casein (pI 5.1), were selected as model proteins. In addition to the previously shown tryptic digestion, proteolysis with endoproteinase Asp-N was also performed. Digestion of these acidic and basic pI proteins produced a few peptides with extreme pI values lying outside the trapping range of the discontinuous buffer. An alteration in the peptide trapping procedure was made to accommodate these analytes. Offline MALDI mass spectral analysis confirmed the presence of the expected peptides. The presented miniaturized sample pretreatment methodology was proven to be applicable on proteins with a moderately wide range of pI. Flexibility in the choice of protease was also evident.

Hypolipidaemic Effect of Hericium erinaceum Grown in Artemisia capillaris on Obese Rats.

Science.gov (United States)

Choi, Won-Sik; Kim, Young-Sun; Park, Byeoung-Soo; Kim, Jang-Eok; Lee, Sung-Eun

2013-06-01

In this study, ethanolic extracts from Hericium erinaceum cultivated with Artemisia capillaris (HEAC) were assessed for their ability to lower the cholesterol levels of male Sprague-Dawley rats fed a high-fat diet. Rats were randomly subdivided into seven test groups. Each group contained eight rats fed a high-fat diet during a growth period lasting 4 wk. Supplementation with the extracts was performed once a day for 2 wk after the high-fat diet. The control group (rats fed a high-fat diet) showed a high efficiency ratio (feed efficiency ratio) value compared to the normal group. Biochemical parameters, including total cholesterol (TC), low-density lipoprotein-cholesterol (LDL-c), and triglyceride (TG) levels dramatically increased in the control group compared to the normal group. High-density lipoprotein-cholesterol (HDL-c) content in the control group was also significantly lower relative to the normal group. Two positive control groups, treated with simvastatin and atorvastatin, had lowered TC, LDL-c, and TG levels, and increased HDL-c content compared to the control group. Treatment with the tested extracts, including HEAC, ethanolic extracts from Hericium erinaceum, and ethanolic extracts from Artemisia capillaris reduced TC, LDL-c, and TG levels and elevated HDL-c content in the hyperlipidemia rats. The atherogenic index and cardiac risk factor values for the HEAC-treated group were 0.95 and 1.95, respectively. Simvastatin- and atorvastatin-treated groups showed atherogenic index values of 1.56 and 1.69, respectively, and cardiac risk factor values of 2.56 and 2.69, respectively. These results show HEAC possesses an ability to cure hyperlipidemia in rats and may serve as an effective natural medicine for treating hyperlipidemia in humans.

Gas transport and separation with ceramic membranes. Part I: Multilayer diffusion and capillary condensation

NARCIS (Netherlands)

Uhlhorn, R.J.R.; Uhlhorn, R.J.R.; Keizer, Klaas; Burggraaf, Anthonie; Burggraaf, A.J.

1992-01-01

Multilayer diffusion and capillary condensation of propylene on supported γ-alumina films greatly improved the permeability and selectivity. Multilayer diffusion, occurring at relative pressures of 0.4 to 0.8 strongly increased the permeability of 6 times the Knudsen permeability, yielding

Nanoscale Capillary Flows in Alumina: Testing the Limits of Classical Theory.

Science.gov (United States)

Lei, Wenwen; McKenzie, David R

2016-07-21

Anodic aluminum oxide (AAO) membranes have well-formed cylindrical channels, as small as 10 nm in diameter, in a close packed hexagonal array. The channels in AAO membranes simulate very small leaks that may be present for example in an aluminum oxide device encapsulation. The 10 nm alumina channel is the smallest that has been studied to date for its moisture flow properties and provides a stringent test of classical capillary theory. We measure the rate at which moisture penetrates channels with diameters in the range of 10 to 120 nm with moist air present at 1 atm on one side and dry air at the same total pressure on the other. We extend classical theory for water leak rates at high humidities by allowing for variable meniscus curvature at the entrance and show that the extended theory explains why the flow increases greatly when capillary filling occurs and enables the contact angle to be determined. At low humidities our measurements for air-filled channels agree well with theory for the interdiffusive flow of water vapor in air. The flow rate of water-filled channels is one order of magnitude less than expected from classical capillary filling theory and is coincidentally equal to the helium flow rate, validating the use of helium leak testing for evaluating moisture flows in aluminum oxide leaks.

Nonaqueous capillary electrophoresis of dextromethorphan and its metabolites.

Science.gov (United States)

Pelcová, Marta; Langmajerová, Monika; Cvingráfová, Eliška; Juřica, Jan; Glatz, Zdeněk

2014-10-01

This study deals with the nonaqueous capillary electrophoretic separation of dextromethorphan and its metabolites using a methanolic background electrolyte. The optimization of separation conditions was performed in terms of the resolution of dextromethorphan and dextrorphan and the effect of separation temperature, voltage, and the characteristics of the background electrolyte were studied. Complete separation of all analytes was achieved in 40 mM ammonium acetate dissolved in methanol. Hydrodynamic injection was performed at 3 kPa for 4 s. The separation voltage was 20 kV accompanied by a low electric current. The ultraviolet detection was performed at 214 nm, the temperature of the capillary was 25°C. These conditions enabled the separation of four analytes plus the internal standard within 9 min. Further, the developed method was validated in terms of linearity, sensitivity, and repeatability. Rat liver perfusate samples were subjected to the nonaqueous capillary electrophoretic method to illustrate its applicability. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Condensation and evaporation transitions in deep capillary grooves

International Nuclear Information System (INIS)

Malijevský, Alexandr; Parry, Andrew O

2014-01-01

We study the order of capillary condensation and evaporation transitions of a simple fluid adsorbed in a deep capillary groove using a fundamental measure density functional theory (DFT). The walls of the capillary interact with the fluid particles via long-ranged, dispersion, forces while the fluid-fluid interaction is modelled as a truncated Lennard–Jones-like potential. We find that below the wetting temperature T w condensation is first-order and evaporation is continuous with the metastability of the condensation being well described by the complementary Kelvin equation. In contrast above T w both phase transitions are continuous and their critical singularities are determined. In addition we show that for the evaporation transition above T w there is an elegant mapping, or covariance, with the complete wetting transition occurring at a planar wall. Our numerical DFT studies are complemented by analytical slab model calculations which explain how the asymmetry between condensation and evaporation arises out of the combination of long-ranged forces and substrate geometry. (paper)

Condensation and evaporation transitions in deep capillary grooves.

Science.gov (United States)

Malijevský, Alexandr; Parry, Andrew O

2014-09-03

We study the order of capillary condensation and evaporation transitions of a simple fluid adsorbed in a deep capillary groove using a fundamental measure density functional theory (DFT). The walls of the capillary interact with the fluid particles via long-ranged, dispersion, forces while the fluid-fluid interaction is modelled as a truncated Lennard-Jones-like potential. We find that below the wetting temperature Tw condensation is first-order and evaporation is continuous with the metastability of the condensation being well described by the complementary Kelvin equation. In contrast above Tw both phase transitions are continuous and their critical singularities are determined. In addition we show that for the evaporation transition above Tw there is an elegant mapping, or covariance, with the complete wetting transition occurring at a planar wall. Our numerical DFT studies are complemented by analytical slab model calculations which explain how the asymmetry between condensation and evaporation arises out of the combination of long-ranged forces and substrate geometry.

Biofabrication of Tobacco mosaic virus-nanoscaffolded supercapacitors via temporal capillary microfluidics

Science.gov (United States)

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.

Streptavidin-functionalized capillary immune microreactor for highly efficient chemiluminescent immunoassay

Energy Technology Data Exchange (ETDEWEB)

Yang Zhanjun [State Key Laboratory of Analytical Chemistry for Life Science, Department of Chemistry, Nanjing University, Nanjing 210093 (China); College of Chemistry and Engineering, Yangzhou University, 88 South University Avenue, Yangzhou 225002 (China); Zong Chen [State Key Laboratory of Analytical Chemistry for Life Science, Department of Chemistry, Nanjing University, Nanjing 210093 (China); Ju Huangxian, E-mail: hxju@nju.edu.cn [State Key Laboratory of Analytical Chemistry for Life Science, Department of Chemistry, Nanjing University, Nanjing 210093 (China); Yan Feng, E-mail: yanfeng2007@sohu.com [Jiangsu Institute of Cancer Prevention and Cure, Nanjing 210009 (China)

2011-11-07

Highlights: {yields} A novel capillary immune microreactor was proposed for highly efficient flow-through chemiluminescent immunoassay. {yields} The microreactor was prepared by functionalizing capillary inner wall with streptavidin for capture of biotinylated antibody. {yields} The proposed immunoassay method showed wide dynamic range, good reproducibility, stability and practicality. {yields} The microreactor was low-cost and disposable, and possessed several advantages over the conventional immunoreactors. - Abstract: A streptavidin functionalized capillary immune microreactor was designed for highly efficient flow-through chemiluminescent (CL) immunoassay. The functionalized capillary could be used as both a support for highly efficient immobilization of antibody and a flow cell for flow-through immunoassay. The functionalized inner wall and the capture process were characterized using scanning electron microscopy. Compared to conventional packed tube or thin-layer cell immunoreactor, the proposed microreactor showed remarkable properties such as lower cost, simpler fabrication, better practicality and wider dynamic range for fast CL immunoassay with good reproducibility and stability. Using {alpha}-fetoprotein as model analyte, the highly efficient CL flow-through immunoassay system showed a linear range of 3 orders of magnitude from 0.5 to 200 ng mL{sup -1} and a low detection limit of 0.1 ng mL{sup -1}. The capillary immune microreactor could make up the shortcoming of conventional CL immunoreactors and provided a promising alternative for highly efficient flow-injection immunoassay.

Invariance of the solid-liquid interfacial energy in electrowetting probed via capillary condensation.

Science.gov (United States)

Gupta, Rohini; Olivier, Gloria K; Frechette, Joelle

2010-07-20

Capillary condensation is employed to probe the solid-liquid interfacial energy in electrowetting on dielectric. The height of an annular water meniscus formed via capillary condensation inside the surface force apparatus is measured as a function of the potential applied across the meniscus and the dielectric stack where the meniscus is formed. According to the Kelvin equation, a decrease in the solid-liquid interfacial energy at constant temperature and relative humidity should lead to an increase in the meniscus height. Our experimental results on nanometer-sized meniscus are in agreement with the work of Mugele [J. Phys.: Condens. Matter 2007, 19, 375112] and unequivocally demonstrate that the real contact angle (or the solid-liquid interfacial energy) remains unaltered in electrowetting on dielectric.

Perturbations of the flow induced by a microcapsule in a capillary tube

Energy Technology Data Exchange (ETDEWEB)

Gubspun, J; Deschamps, J; Georgelin, M; Leonetti, M [Aix-Marseille Université, CNRS, Centrale Marseille, IRPHE, UMR7342, F-13384, Marseille (France); Loubens, C de [Universite Grenoble Alpes, LRP, F-38000 Grenoble (France); Trozzo, R [Aix-Marseille Université, CNRS, Centrale Marseille, M2P2, UMR7340, F-13451, Marseille (France); Edwards-Levy, F, E-mail: leonetti@irphe.univ-mrs.fr [Institut de Chimie Moléculaire de Reims, UMR7312, CNRS-Université de Reims Champagne Ardenne, F-51100 Reims (France)

2017-06-15

Soft microcapsules moving in a cylindrical capillary deform from quasi-spherical shapes to elongated shapes with an inversion of curvature at the rear. We investigated the perturbation of the flow by particle tracking velocimetry around deformed microcapsules in confined flow. These experiments are completed by numerical simulations. Microcapsules are made of a thin membrane of polymerized human albumin and their shear elastic moduli are previously characterized in a cross flow chamber. Firstly, the velocity of the microcapsule can be calculated by theoretical predictions for rigid spheres, even for large deformations as ‘parachute-like’ shapes, if a relevant definition of the ratio of confinement is chosen. Secondly, at the rear and the front of the microcapsule, the existence of multiple recirculation regions is governed by the local curvature of the membrane. The amplitudes of these perturbations increase with the microcapsule deformation, whereas their axial extents are comparable to the radius of the capillary whatever the confinement and the capillary number. We conclude that whereas the motion of microcapsules in confined flow has quantitative similitudes with rigid spheres in terms of velocity and axial extent of the perturbation, their presence induces variations in the flow field that are related to the local deformation of the membrane as in droplets. (paper)

Impact of capillary rise and recirculation on simulated crop yields

Science.gov (United States)

Kroes, Joop; Supit, Iwan; van Dam, Jos; van Walsum, Paul; Mulder, Martin

2018-05-01

Upward soil water flow is a vital supply of water to crops. The purpose of this study is to determine if upward flow and recirculated percolation water can be quantified separately, and to determine the contribution of capillary rise and recirculated water to crop yield and groundwater recharge. Therefore, we performed impact analyses of various soil water flow regimes on grass, maize and potato yields in the Dutch delta. Flow regimes are characterized by soil composition and groundwater depth and derived from a national soil database. The intermittent occurrence of upward flow and its influence on crop growth are simulated with the combined SWAP-WOFOST model using various boundary conditions. Case studies and model experiments are used to illustrate the impact of upward flow on yield and crop growth. This impact is clearly present in situations with relatively shallow groundwater levels (85 % of the Netherlands), where capillary rise is a well-known source of upward flow; but also in free-draining situations the impact of upward flow is considerable. In the latter case recirculated percolation water is the flow source. To make this impact explicit we implemented a synthetic modelling option that stops upward flow from reaching the root zone, without inhibiting percolation. Such a hypothetically moisture-stressed situation compared to a natural one in the presence of shallow groundwater shows mean yield reductions for grassland, maize and potatoes of respectively 26, 3 and 14 % or respectively about 3.7, 0.3 and 1.5 t dry matter per hectare. About half of the withheld water behind these yield effects comes from recirculated percolation water as occurs in free-drainage conditions and the other half comes from increased upward capillary rise. Soil water and crop growth modelling should consider both capillary rise from groundwater and recirculation of percolation water as this improves the accuracy of yield simulations. This also improves the accuracy of the

Abnormal myocardial capillary density in apical hypertrophic cardiomyopathy can be assessed by myocardial contrast echocardiography

International Nuclear Information System (INIS)

Moon, Jeonggeun; Cho, In-Jeong; Shim, Chi-Young; Ha, Jong-Won; Jang, Yangsoo; Chung, Namsik; Rim, Se-Joong

2010-01-01

Myocardial ischemia and dysfunction can occur in hypertrophic cardiomyopathy (HCM) because of the high muscle-to-blood ratio, even without significant coronary artery disease. Microbubbles reside only in the intravascular space and myocardial video-intensity during systole results mostly from microbubbles within capillaries. The hypothesis explored in the present study was that an abnormal capillary density in apical HCM (ApHCM) can be demonstrated using myocardial contrast echocardiography (MCE). The 56 patients were investigated (31 males, age 58±9 years; 33 ApHCM, 9 hypertensive left ventricular hypertrophy [LVH], 14 controls). MCE was performed with low-mechanical-index power modulation imaging. Tissue Doppler imaging to assess myocardial contractile function was obtained at the mitral annulus (S'), and 99m Tc-MIBI single photon emission computed tomography (SPECT) was also performed. All ApHCM patients exhibited perfusion defects at the hypertrophied segments in the systolic phase during MCE, whereas SPECT showed normal or rather increased perfusion at those sites. The cyclic variation of video-intensity was exaggerated in ApHCM when compared with the LVH or control group (% of [systolic video-intensity]/[diastolic video-intensity]: 33.0±12.3%, 88.3±19.2% and 79.4±13.9%, respectively [P<0.05]). Concurrently, MCE cyclic variation and perfusion defect size were related to decreased S' (P<0.05 for all). A perfusion defect at the hypertrophied segment, representing abnormal myocardial capillary density, was observed in ApHCM patients during MCE. The extent of MCE cyclic variation and the perfusion defect size both correlate with decreased myocardial contractile property in ApHCM. (author)

The order of condensation in capillary grooves.

Science.gov (United States)

Rascón, Carlos; Parry, Andrew O; Nürnberg, Robert; Pozzato, Alessandro; Tormen, Massimo; Bruschi, Lorenzo; Mistura, Giampaolo

2013-05-15

We consider capillary condensation in a deep groove of width L. The transition occurs at a pressure p(co)(L) described, for large widths, by the Kelvin equation p(sat) - p(co)(L) = 2σ cosθ/L, where θ is the contact angle at the side walls and σ is the surface tension. The order of the transition is determined by the contact angle of the capped end θcap; it is continuous if the liquid completely wets the cap, and first-order otherwise. When the transition is first-order, corner menisci at the bottom of the capillary lead to a pronounced metastability, determined by a complementary Kelvin equation Δp(L) = 2σ sinθcap/L. On approaching the wetting temperature of the capillary cap, the corner menisci merge and a single meniscus unbinds from the bottom of the groove. Finite-size scaling shifts, crossover behaviour and critical singularities are determined at mean-field level and beyond. Numerical and experimental results showing the continuous nature of condensation for θcap = 0 and the influence of corner menisci on adsorption isotherms are presented.

The order of condensation in capillary grooves

International Nuclear Information System (INIS)

Rascón, Carlos; Parry, Andrew O; Nürnberg, Robert; Pozzato, Alessandro; Tormen, Massimo; Bruschi, Lorenzo; Mistura, Giampaolo

2013-01-01

We consider capillary condensation in a deep groove of width L. The transition occurs at a pressure p co (L) described, for large widths, by the Kelvin equation p sat − p co (L) = 2σcosθ/L, where θ is the contact angle at the side walls and σ is the surface tension. The order of the transition is determined by the contact angle of the capped end θ cap ; it is continuous if the liquid completely wets the cap, and first-order otherwise. When the transition is first-order, corner menisci at the bottom of the capillary lead to a pronounced metastability, determined by a complementary Kelvin equation Δp(L) = 2σsinθ cap /L. On approaching the wetting temperature of the capillary cap, the corner menisci merge and a single meniscus unbinds from the bottom of the groove. Finite-size scaling shifts, crossover behaviour and critical singularities are determined at mean-field level and beyond. Numerical and experimental results showing the continuous nature of condensation for θ cap = 0 and the influence of corner menisci on adsorption isotherms are presented. (fast track communication)

Influence of local capillary trapping on containment system effectiveness

Energy Technology Data Exchange (ETDEWEB)

Bryant, Steven [University Of Texas At Austin, Austin, TX (United States). Center for Petroleum and Geosystems Engineering

2014-03-31

implications for GCS. The first is that LCT can retain a significant fraction of the CO₂ 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, CO₂ 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 CO₂ 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 CO₂ 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.

Controlled capillary assembly of magnetic Janus Particles at fluid-fluid interfaces

NARCIS (Netherlands)

Xie, Q.; Davies, G.B.; Harting, J.D.R.

2016-01-01

Capillary interactions can be used to direct assembly of particles adsorbed at fluid-fluid interfaces. Precisely controlling the magnitude and direction of capillary interactions to assemble particles into favoured structures for materials science purposes is desirable but challenging. In this

Filling of charged cylindrical capillaries

NARCIS (Netherlands)

Das, Siddhartha; Chanda, Sourayon; Eijkel, J.C.T.; Tas, N.R.; Chakraborty, Suman; Mitra, Sushanta K.

2014-01-01

We provide an analytical model to describe the filling dynamics of horizontal cylindrical capillaries having charged walls. The presence of surface charge leads to two distinct effects: It leads to a retarding electrical force on the liquid column and also causes a reduced viscous drag force because

A two-angle model of dynamic wetting in microscale capillaries under low capillary numbers with experiments.

Science.gov (United States)

Lei, Da; Lin, Mian; Li, Yun; Jiang, Wenbin

2018-06-15

An accurate model of the dynamic contact angle θ d is critical for the calculation of capillary force in applications like enhanced oil recovery, where the capillary number Ca ranges from 10 -10 to 10 -5 and the Bond number Bo is less than 10 -4 . The rate-dependence of the dynamic contact angle under such conditions remains blurred, and is the main target of this study. Featuring with pressure control and interface tracking, the innovative experimental system presented in this work achieves the desired ranges of Ca and Bo, and enables the direct optical measurement of dynamic contact angles in capillaries as tiny as 40 × 20 (width × height) μm and 80 × 20 μm. The advancing and receding processes of wetting and nonwetting liquids were tested. The dynamic contact angle was confirmed velocity-independent with 10 -9  contact line velocity V = 0.135-490 μm/s) and it can be described by a two-angle model with desirable accuracy. A modified two-angle model was developed and an empirical form was obtained from experiments. For different liquids contacting the same surface, the advancing angle θ adv approximately equals the static contact angle θ o . The receding angle θ rec was found to be a linear function of θ adv , in good agreement with our and other experiments from the literature. Copyright © 2018 Elsevier Inc. All rights reserved.

Quantification of local matrix deformations and mechanical properties during capillary morphogenesis in 3D.

Science.gov (United States)

Kniazeva, Ekaterina; Weidling, John W; Singh, Rahul; Botvinick, Elliot L; Digman, Michelle A; Gratton, Enrico; Putnam, Andrew J

2012-04-01

Reciprocal mechanical interactions between cells and the extracellular matrix (ECM) are thought to play important instructive roles in branching morphogenesis. However, most studies to date have failed to characterize these interactions on a length scale relevant to cells, especially in three-dimensional (3D) matrices. Here we utilized two complementary methods, spatio-temporal image correlation spectroscopy (STICS) and laser optical tweezers-based active microrheology (AMR), to quantify endothelial cell (EC)-mediated deformations of individual ECM elements and the local ECM mechanical properties, respectively, during the process of capillary morphogenesis in a 3D cell culture model. In experiments in which the ECM density was systematically varied, STICS revealed that the rate at which ECs deformed individual ECM fibers on the microscale positively correlated with capillary sprouting on the macroscale. ECs expressing constitutively active V14-RhoA displaced individual matrix fibers at significantly faster rates and displayed enhanced capillary sprouting relative to wild-type cells, while those expressing dominant-negative N19-RhoA behaved in an opposite fashion. In parallel, AMR revealed a local stiffening of the ECM proximal to the tips of sprouting ECs. By quantifying the dynamic physical properties of the cell-ECM interface in both space and time, we identified a correlation linking ECM deformation rates and local ECM stiffening at the microscale with capillary morphogenesis at the macroscale. This journal is © The Royal Society of Chemistry 2012

Infraglottic lobular capillary hemangioma: A case report

Directory of Open Access Journals (Sweden)

Vinh Ly Pham Hoang

2018-03-01

Full Text Available Lobular capillary hemangioma (LCH is a benign proliferation of capillary blood vessels adopting a lobular configuration. A laryngeal origin of LCH is exceedingly rare. Here, we describe a case of an 11-year-old boy presenting with a subglottic lesion, leading to a subglottic stenosis. Histopathologic findings of the lesion implicated an LCH, which was removed successfully by a coblator. This is the first report of a subglottic LCH. Physicians should be aware of this unique lesion and laryngeal LCH should be considered in diagnosing the cause of a subglottic stenosis. Additionally, coblation should be an effective treatment for laryngeal LCH.

Evaluation of laser Doppler flowmetry for measurement of capillary blood flow in the stomach wall of dogs during gastric dilatation-volvulus.

Science.gov (United States)

Monnet, Eric; Pelsue, Davyd; MacPhail, Catriona

2006-02-01

To validate laser doppler flowmetry (LDF) for measurement of blood flow in the stomach wall of dogs with gastric dilatation-volvulus (GDV). Six purpose-bred dogs and 24 dogs with naturally occurring GDV. Experimental and clinical. Capillary blood flow in the body of the stomach and pyloric antrum was measured with LDF (tissue perfusion unit (TPU) before and after induction of portal hypertension (PH) and after PH plus gastric ischemia (GI; PH + GI) and compared with flow measured by colored microsphere technique. Capillary flow was measured by LDF in the stomach wall of dogs with GDV. PH and PH+GI induced a significant reduction in blood flow in the body of the stomach (P = .019). A significant positive correlation was present between percent changes in capillary blood flow measured by LDF and colored microspheres after induction of PH + GI in the body of the stomach (r = 0.94, P = .014) and in the pyloric antrum (r = 0.95, P = .049). Capillary blood flow measured in the body of the stomach of 6 dogs that required partial gastrectomy (5.00+/-3.30 TPU) was significantly lower than in dogs that did not (28.00+/-14.40 TPU, P = .013). LDF can detect variations in blood flow in the stomach wall of dogs. LDF may have application for evaluation of stomach wall viability during surgery in dogs with GDV.

Quantification of local matrix deformations and mechanical properties during capillary morphogenesis in 3D†‡

Science.gov (United States)

Kniazeva, Ekaterina; Weidling, John W.; Singh, Rahul; Botvinick, Elliot L.; Digman, Michelle A.; Gratton, Enrico

2013-01-01

Reciprocal mechanical interactions between cells and the extracellular matrix (ECM) are thought to play important instructive roles in branching morphogenesis. However, most studies to date have failed to characterize these interactions on a length scale relevant to cells, especially in three-dimensional (3D) matrices. Here we utilized two complementary methods, spatio-temporal image correlation spectroscopy (STICS) and laser optical tweezers-based active microrheology (AMR), to quantify endothelial cell (EC)-mediated deformations of individual ECM elements and the local ECM mechanical properties, respectively, during the process of capillary morphogenesis in a 3D cell culture model. In experiments in which the ECM density was systematically varied, STICS revealed that the rate at which ECs deformed individual ECM fibers on the microscale positively correlated with capillary sprouting on the macroscale. ECs expressing constitutively active V14-RhoA displaced individual matrix fibers at significantly faster rates and displayed enhanced capillary sprouting relative to wild-type cells, while those expressing dominant-negative N19-RhoA behaved in an opposite fashion. In parallel, AMR revealed a local stiffening of the ECM proximal to the tips of sprouting ECs. By quantifying the dynamic physical properties of the cell-ECM interface in both space and time, we identified a correlation linking ECM deformation rates and local ECM stiffening at the microscale with capillary morphogenesis at the macroscale. PMID:22281872

In-capillary self-assembly and proteolytic cleavage of polyhistidine peptide capped quantum dots

Energy Technology Data Exchange (ETDEWEB)

Wang, Jianhao; Li, Jingyan; Li, Jinchen; Liu, Feifei [School of Pharmaceutical Engineering and Life Science, Changzhou University, Changzhou, Jiangsu, 213164 (China); Zhou, Xiang; Yao, Yi [Changzhou Qianhong Bio-pharma Co. Ltd, Changzhou 213164, Jiangsu (China); Wang, Cheli [School of Pharmaceutical Engineering and Life Science, Changzhou University, Changzhou, Jiangsu, 213164 (China); Qiu, Lin, E-mail: linqiupjj@gmail.com [School of Pharmaceutical Engineering and Life Science, Changzhou University, Changzhou, Jiangsu, 213164 (China); Jiang, Pengju, E-mail: pengju.jiang@gmail.com [School of Pharmaceutical Engineering and Life Science, Changzhou University, Changzhou, Jiangsu, 213164 (China); State Key Laboratory of Pharmaceutical Biotechnology, Nanjing, Jiangsu (China)

2015-10-01

A new method using fluorescence coupled capillary electrophoresis (CE-FL) for monitoring self-assembly and proteolytic cleavage of hexahistidine peptide capped quantum dots (QDs) inside a capillary has been developed in this report. QDs and the ATTO 590-labeled hexahistidine peptide (H6-ATTO) were injected into a capillary, sequentially. Their self-assembly inside the capillary was driven by a metal-affinity force which yielded a new fluorescence signal due to Förster resonance energy transfer (FRET). The highly efficient separation of fluorescent complexes and the FRET process were analyzed using CE-FL. The self-assembly of QDs and biomolecules was found to effectively take place inside the capillary. The kinetics of the assembly was monitored by CE-FL, and the approach was extended to the study of proteolytic cleavage of surface conjugated peptides. Being the first in-depth analysis of in-capillary nanoparticle–biomolecule assembly, the novel approach reported here provides inspiration to the development of QD-based FRET probes for biomedical applications. - Highlights: • We examined the self-assembly QDs with H6-ATTO inside a capillary. • We prove CE-FL to be a powerful method to resolve QDs-H6-ATTO complex. • We achieve chromatographic separation of QDs-H6-ATTO complex. • We discovered a novel strategy for the online detection of thrombin. • This technique integrated “injection, mixing, reaction, separation and detection”.

The HO-1/CO system regulates mitochondrial-capillary density relationships in human skeletal muscle.

Science.gov (United States)

Pecorella, Shelly R H; Potter, Jennifer V F; Cherry, Anne D; Peacher, Dionne F; Welty-Wolf, Karen E; Moon, Richard E; Piantadosi, Claude A; Suliman, Hagir B

2015-10-15

The heme oxygenase-1 (HO-1)/carbon monoxide (CO) system induces mitochondrial biogenesis, but its biological impact in human skeletal muscle is uncertain. The enzyme system generates CO, which stimulates mitochondrial proliferation in normal muscle. Here we examined whether CO breathing can be used to produce a coordinated metabolic and vascular response in human skeletal muscle. In 19 healthy subjects, we performed vastus lateralis muscle biopsies and tested one-legged maximal O2 uptake (V̇o2max) before and after breathing air or CO (200 ppm) for 1 h daily for 5 days. In response to CO, there was robust HO-1 induction along with increased mRNA levels for nuclear-encoded mitochondrial transcription factor A (Tfam), cytochrome c, cytochrome oxidase subunit IV (COX IV), and mitochondrial-encoded COX I and NADH dehydrogenase subunit 1 (NDI). CO breathing did not increase V̇o2max (1.96 ± 0.51 pre-CO, 1.87 ± 0.50 post-CO l/min; P = not significant) but did increase muscle citrate synthase, mitochondrial density (139.0 ± 34.9 pre-CO, 219.0 ± 36.2 post-CO; no. of mitochondrial profiles/field), myoglobin content and glucose transporter (GLUT4) protein level and led to GLUT4 localization to the myocyte membrane, all consistent with expansion of the tissue O2 transport system. These responses were attended by increased cluster of differentiation 31 (CD31)-positive muscle capillaries (1.78 ± 0.16 pre-CO, 2.37 ± 0.59 post-CO; capillaries/muscle fiber), implying the enrichment of microvascular O2 reserve. The findings support that induction of the HO-1/CO system by CO not only improves muscle mitochondrial density, but regulates myoglobin content, GLUT4 localization, and capillarity in accordance with current concepts of skeletal muscle plasticity. Copyright © 2015 the American Physiological Society.

Capillary Ion Concentration Polarization for Power-Free Salt Purification

Science.gov (United States)

Park, Sungmin; Jung, Yeonsu; Cho, Inhee; Kim, Ho-Young; Kim, Sung Jae

2014-11-01

In this presentation, we experimentally and theoretically demonstrated the capillary based ion concentration polarization for power-free salt purification system. Traditional ion concentration polarization phenomenon has been studied for a decade for both fundamental nanoscale fluid dynamics and novel engineering applications such as desalination, preconcentration and energy harvesting devices. While the conventional system utilizes an external power source, the system based on capillary ion concentration polarization is capable of perm-selective ion transportation only by capillarity so that the same ion depletion zone can be formed without any external power sources. An ion concentration profile near the nanostructure was tracked using fluorescent probes and analyzed by solving the modified Nernst-Planck equation. As a result, the concentration in the vicinity of the nanostructure was at least 10 times lower than that of bulk electrolyte and thus, the liquid absorbed into the nanostructure had the low concentration. This mechanism can be used for the power free salt purification system which would be significantly useful in underdeveloped and remote area. This work was supported by Samsung Research Funding Center of Samsung Electronics under Project Number SRFC-MA1301-02.

Semi-automatic assessment of skin capillary density: proof of principle and validation.

Science.gov (United States)

Gronenschild, E H B M; Muris, D M J; Schram, M T; Karaca, U; Stehouwer, C D A; Houben, A J H M

2013-11-01

Skin capillary density and recruitment have been proven to be relevant measures of microvascular function. Unfortunately, the assessment of skin capillary density from movie files is very time-consuming, since this is done manually. This impedes the use of this technique in large-scale studies. We aimed to develop a (semi-) automated assessment of skin capillary density. CapiAna (Capillary Analysis) is a newly developed semi-automatic image analysis application. The technique involves four steps: 1) movement correction, 2) selection of the frame range and positioning of the region of interest (ROI), 3) automatic detection of capillaries, and 4) manual correction of detected capillaries. To gain insight into the performance of the technique, skin capillary density was measured in twenty participants (ten women; mean age 56.2 [42-72] years). To investigate the agreement between CapiAna and the classic manual counting procedure, we used weighted Deming regression and Bland-Altman analyses. In addition, intra- and inter-observer coefficients of variation (CVs), and differences in analysis time were assessed. We found a good agreement between CapiAna and the classic manual method, with a Pearson's correlation coefficient (r) of 0.95 (Pdifferences between the two methods, with an intercept of the Deming regression of 1.75 (-6.04; 9.54), while the Bland-Altman analysis showed a mean difference (bias) of 2.0 (-13.5; 18.4) capillaries/mm(2). The intra- and inter-observer CVs of CapiAna were 2.5% and 5.6% respectively, while for the classic manual counting procedure these were 3.2% and 7.2%, respectively. Finally, the analysis time for CapiAna ranged between 25 and 35min versus 80 and 95min for the manual counting procedure. We have developed a semi-automatic image analysis application (CapiAna) for the assessment of skin capillary density, which agrees well with the classic manual counting procedure, is time-saving, and has a better reproducibility as compared to the

Capillary condensation in porous alumina observed by positronium lifetime spectroscopy

International Nuclear Information System (INIS)

Ivanov, Eugeniu; Vata, Ion; Toderian, Stefan; Dudu, Dorin; Rusen, Ion; Stefan, Nitisor

2008-01-01

The PALS method based on time distribution measurements has been used to study capillary condensation of different gases adsorbed in microporous alumina powder. The isotherms exhibit features which are associated with a shifted gas-liquid transition. The sorption and desorption processes are irreversible presenting a hysteresis effect. Suggestions on some new aspects of the capillary condensation dynamics are made

[The diagnostic significance of nailfold video-capillaroscopy in systemic sclerosis].

Science.gov (United States)

Li, Lin-Guang; Zhang, Jiang-Lin; Liu, Xiu-Hua; Huang, Feng

2012-05-01

To observe nailfold capillary changes in a cohort of connective tissue disease (CTD) with Raynaud's phenomenon (RP) and to explore the diagnostic value of nailfold video-capillaroscopy (NVC) in systemic sclerosis (SSc). Sixty CTD patients with RP divided into SSc group (n = 36) and non-SSc group (n = 24) were referred to an experienced operator for NVC. The patients had decreased capillary loops in SSc group with the capillary diameter more enlarged in SSc group than non-SSc group. The number of patients in SSc group with giant capillaries was 14, while 3 in non-SSc group. There were 23 patients with haemorrhages in SSc group and 9 in non-SSc group. The number of patients with severe effusion was 15 in SSc group, while 2 in non-SSc group. By using the ROC curves, indexes with AUC at least 0.7 of the input capillary diameter, the output capillary diameter, the middle capillary diameter, blood color and effusion for the diagnostic cutoff points were 18.5 µm, 24.5 µm, 19.5µm, deep red and severe effusion. With at least 2 out of the top 3 indexes, the diagnostic sensitivity and specificity of SSc were higher. CTD Patients with RP of SSc have less capillary loops, more enlarged capillaries, more giant capillaries, more severe effusion and more haemorrhages than non-SSc patients. The characteristics of nailfold capillary changes in SSc patients with RP can be helpful for the diagnosis and the differential diagnosis of SSc.

Integration of amperometric sensors for microchip capillary electrophoresis application

International Nuclear Information System (INIS)

Dicorato, F; Moore, E; Glennon, J

2011-01-01

Capillary electrophoresis is a technique for the separation and analysis of chemical compounds. Techniques adopted from the microchip technology knowledge have led to recent developments of electrophoresis system with integration on microchip. Microchip Capillary Electrophoresis (μCE) systems offer a series of advantages as easy integration for Lab-on-a-chip applications, high performance, portability, speed, minimal solvent and sample requirements. A new technological challenge aims at the development of an economic modular microchip capillary electrophoresis systems using separable and independent units concerning the sensor. In this project we worked on the development of an interchangeable amperometric sensor in order to provide a solution to such electrode passivation and facilitating the use of tailored sensors for specific analyte detection besides. Fluidic chips have been machined from cyclic olefin polymer pallets (Zeonor) using a micro-injection molding machine.

Integration of amperometric sensors for microchip capillary electrophoresis application

Energy Technology Data Exchange (ETDEWEB)

Dicorato, F; Moore, E [Life Sciences Interface Group, Tyndall National Institute, Lee Maltings, Dyke Parade, Cork (Ireland); Glennon, J, E-mail: eric.moore@tyndall.ie [Chemistry Department, University College Cork, College Road, Cork (Ireland)

2011-08-17

Capillary electrophoresis is a technique for the separation and analysis of chemical compounds. Techniques adopted from the microchip technology knowledge have led to recent developments of electrophoresis system with integration on microchip. Microchip Capillary Electrophoresis ({mu}CE) systems offer a series of advantages as easy integration for Lab-on-a-chip applications, high performance, portability, speed, minimal solvent and sample requirements. A new technological challenge aims at the development of an economic modular microchip capillary electrophoresis systems using separable and independent units concerning the sensor. In this project we worked on the development of an interchangeable amperometric sensor in order to provide a solution to such electrode passivation and facilitating the use of tailored sensors for specific analyte detection besides. Fluidic chips have been machined from cyclic olefin polymer pallets (Zeonor) using a micro-injection molding machine.

Surface tension in microsystems engineering below the capillary length

CERN Document Server

Lambert, Pierre

2014-01-01

This book describes how surface tension effects can be used by engineers to provide mechanical functions in miniaturized products (<1 mm). Even if precursors of this field such as Jurin or Laplace already date back to the 18th century, describing surface tension effects from a mechanical perspective is very recent. The originality of this book is to consider the effects of capillary bridges on solids, including forces and torques exerted both statically and dynamically by the liquid along the 6 degrees-of-freedom. It provides a comprehensive approach to various applications, such as capillary adhesion (axial force), centering force in packaging and micro-assembly (lateral force) and recent developments such as a capillary motor (torque). It devises how surface tension can be used to provide mechanical functions such as actuation (bubble-actuated compliant table), sealing and tightness, energy harvesting, nanodispending.

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

Science.gov (United States)

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

Capillary condensation, invasion percolation, hysteresis, and discrete memory

International Nuclear Information System (INIS)

Guyer, R.A.; McCall, K.R.

1996-01-01

A model of the capillary condensation process, i.e., of adsorption-desorption isotherms, having only pore-pore interactions is constructed. The model yields (1) hysteretic isotherms, (2) invasion percolation on desorption, and (3) hysteresis with discrete memory for interior chemical potential loops. All of these features are seen in experiment. The model is compared to a model with no pore-pore interactions (the Preisach model) and to a related model of interacting pore systems (the random field Ising model). The capillary condensation model differs from both. copyright 1996 The American Physical Society

Combined contactless conductometric, photometric, and fluorimetric single point detector for capillary separation methods.

Science.gov (United States)

Ryvolová, Markéta; Preisler, Jan; Foret, Frantisek; Hauser, Peter C; Krásenský, Pavel; Paull, Brett; Macka, Mirek

2010-01-01