Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Capillary Action”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 55 records · Page 3Linked to original sources
PubMed1989

The penetration of smear material into dentinal tubules during instrumentation with surface-active reagents: a scanning electron microscopic study.

Thirty freshly extracted, single-rooted anterior teeth were used. They were divided into three groups and instrumented conventionally with #10 to 50 K files. During instrumentation, the K files in the first group were moistened with saline solution, in the second group with 50% sodium dodecylbenzenesulfonate solution, and in the third group with Sulfapon (sodium salt of sulfonated condensation product of ethylen oxide with a fatty acid) solution. After the experimental procedure the specimens were examined in a scanning electron microscope to observe packing of smear material into dentinal tubules. Results showed the surface-active reagents cause the deeper penetration of the smear material into the dentinal tubules. These findings support the hypothesis that the phenomenon of the packing of smear material into the dentinal tubules is by capillary action and fluid dynamics.

Benzenesulfonates↗
PubMed1992

An in vitro model for studying the effects of slime and nonslime-forming Staphylococcus epidermidis contamination of intravenous catheters.

An in vitro model was developed to study the relationship between intravenous catheters, bacteria, and the subcutaneous tunnel. Studies of both slime-forming and nonslime-forming coagulase negative Staphylococcus epidermidis show that slime formation enhances capillary action of coagulase negative S. epidermidis. This offers a possible explanation of the increased virulence associated with slime-forming coagulase negative S. epidermidis in the clinical situation.

Agar↗
PubMed2001

[Principle demonstration of nutrient delivery system in a space vegetable planting prototype facility].

Objective. To develop a nutrient delivery system for space vegetable planting prototype facility to be used in future space station, and to preliminarily testify its feasibility through ground-based demonstration experiments. Method. A nutrient delivery system in a space vegetable planting prototype facility was designed and fabricated, and ground based demonstration experiments of plant cultivation were conducted. Result. Nutrient could be steadily delivered to plant cultivation matrixes through capillary action, water content of planting matrixes could be controlled automatically and maintained constant, and the planted material lettuce showed basically normal morphology and color. Conclusion. The nutrient delivery system in a space vegetable planting prototype facility could basically meet the requirements for plant nutrient delivery under space microgravity environmental condition.

Capillary Action↗
PubMed1993

Oil sorption behavior of various sorbents studied by sorption capacity measurement and environmental scanning electron microscopy.

Oil sorption capacities of various natural and man-made fibrous sorbents were compared in a simulated seawater bath containing oil. Natural sorbents such as milkweed, kapok, cotton, and wool showed higher sorption capacities than man-made sorbents such as polyester, polypropylene, viscose rayon, nylon 6, nylon 66, and acetate. Sorption capacities of the natural sorbents were over 30 g oil/g fiber. No definite advantages were observed using man-made bicomponent and biconstituent fibers over regular man-made fibers with respect to their sorption capacity. Analyses of sorption mechanisms using an environmental scanning electron microscope revealed that an oil deposit disappeared from the fiber surface after a certain time interval in milkweed, kapok, and cotton. This suggested that the sorption of oil in these fibers occurred through capillary action, probably due to their hollow lumens. Contrarily, adsorption, a surface phenomenon, would be the most prominent mechanism for oil sorption of wool fibers due to large amounts of surface wax, irregular scaly surfaces, and crimp. Effects of both adsorption and absorption were shown in the oil sorption of man-made fibers, depending upon the type and shape of the sorbent. Dumbbell-like oil deposits were seen on the fiber surface in certain oleophilic man-made fibers, because of a partial wetting of oil on the fiber surface. For some hydrophilic man-made fibers such as polyvinylalcohol and copolymer of isobutylene-maleic anhydride, the physical configuration of the fiber was a decisive factor in determining oil sorpton capacity of the sorbents.

Capillary Action↗
PubMedDate not supplied

Estimation of buspirone-bovine serum albumin binding by affinity capillary electrophoresis.

Drug-protein binding is an important process in pharmacokinetic phase of drug action. Capillary electrophoresis was employed, specifically the Hummel-Dreyer method and Scatchard analysis, to study the interactions of an anxiolytic drug, buspirone, with pure bovine serum albumin (BSA) and with BSA present in the human recombinant 5-HT(1A) serotonin receptor preparation. The binding constant of buspirone with BSA determined in free BSA solution was K = 5.55 x 10(4) M(-1) whereas its value with BSA present in the serotonin receptor preparation was K = 5.57 x 10(4) M(-1). The method was found to be inadequate for measuring the specific binding interactions between buspirone and the 5-HT(1A) receptor in the preparation employed.

Animals↗
PubMedDate not supplied

Chiral separations of pharmaceuticals using capillary electrochromatography (CEC): an overview.

Enantiomers of bioactive molecules often differ in potency, toxicity, metabolism, and pharmacological actions. Capillary electrochromatography (CEC) is an emerging separation technique being investigated for use in chiral separations. CEC is a hybrid of HPLC and CE. CEC combines the electrophoretic mobility of CE with the partitioning mechanisms of HPLC. In this overview, several resolution mechanisms commonly used in CEC and the main parameters influencing the selectivity of the chiral separation will be discussed. Current applications of CEC in chiral separations of pharmaceuticals will be provided for each type of resolution mechanism. Finally, the advantages and limitations of CEC will be described, followed by the future outlook for CEC.

Electrophoresis, Capillary↗
PubMed2004

Interface motion of capillary-driven flow in rectangular microchannel.

In microchannel flow, gas-liquid interface behavior is important for developing a wide range of microfluidic applications, especially in passive microfluidic systems. This paper presents a discussion of interface motion driven by capillary action in a microchannel. We have extended the theory beyond the previous theory of capillary rise problem for a circular tube, to a rectangular microchannel. The same formula for the relation between nondimensional time and interface position is obtained as for a circular tube. We examined rectangular microchannels with several sizes (about 50 to 100 microm square) of glass capillaries and 85 x 68 microm and 75 x 45 microm polydimethylsiloxane (PDMS) microchannels fabricated by photolithography technique, respectively. We observed movement of the gas-liquid interface position and compared it to the dimensionless relation. We obtained the value of a dimensionless variable of driving force that is related to dynamic contact angles for glass-water, glass-ethanol, and PDMS-ethanol. Using this variable, interface motion can be predicted for any size of rectangular channels.

Journal Article↗
PubMed2006

Ribbon-to-fiber transformation in the process of spinning of carbon-nanotube dispersion.

We describe a phenomenon of ribbon-to-fiber transformation observed in the process of spinning of single wall carbon nanotubes dispersed in polymer solutions. In the process of spinning, a gel-like ribbon comprised of nanotube bundles bound by polymer is withdrawn from a solvent bath. We show that upon crossing the liquid-air interface, the ribbon may either retain its flat shape or fold into a compact hairlike fiber. The ribbon-to-fiber transformation is caused by the capillary action of the liquid meniscus embracing the ribbon. Only sufficiently stiff ribbons can withhold the capillary compression. The critical conditions of folding, as well as the number of folds in the contractive ribbon, depend on the ribbon width, its flexural rigidity, and the solvent surface tension. We show that the ribbon rigidity can be efficiently modulated by varying the solvent composition, allowing us to control the pore structure of carbon-nanotube fibers.

Microscopy, Electron, Scanning↗
PubMed1995

Downward blotting of proteins in a model based on apolipoprotein(a) phenotyping.

Standard immunoblotting ("Western blot") involves electrotransfer of proteins from a separation gel (usually acrylamide) onto a membrane. Recently, a downward capillary method with increased hybridization efficiency was developed for DNA and RNA. The present work assessed the applicability of this method to proteins in a model based on human apolipoprotein(a)[apo(a)] isoforms which consist of a single, >200-kDa polypeptide chain varying in size with a repeat sequence. After reduction treatment and sodium dodecyl sulfate-agarose gel electrophoresis, serum proteins were transferred from the gel by upward or downward (Turboblotter) capillary action onto nitrocellulose membranes in Tris-buffered saline, pH 7.5, at room temperature. Increased detectability of apo(a) isoforms was achieved by substituting comparatively high molar concentrations of protein A for true second antibody. With downward capillary transfer and short 37 degrees C incubations, the apo(a) phenotyping could be completed in about 26 h and required less than 8 h effective processing time. The downward transfer was about twice as fast (complete within 1 h) as the upward version and with this speed it offers a good alternative to electroblotting as well.

Apolipoproteins↗
PubMed1991

Arterial and venous effects of atrial natriuretic peptide in the human forearm.

Atrial natriuretic peptide (ANP) has direct vasodilating properties in addition to its diuretic and natriuretic effects. Furthermore, vascular permeability may be influenced. Because relatively little is known about the venous and capillary actions of ANP in humans, we investigated the spectrum of vascular actions of ANP in the human forearm. In seven healthy subjects, ANP was infused intraarterially in consecutive doses of 0, 10, 50, and 250 ng/100 mL tissue/min together with vehicle or norepinephrine 1 ng/kg/min. In seven other subjects, 0.5 ng/kg/min angiotensin II and 10 ng/kg/min serotonin were used as a constrictor. Venous occlusion plethysmography was used to measure forearm blood flow, venous compliance, capillary filtration rate, and maximum venous outflow. Intraarterial infusion of ANP induced a dose-dependent increase of forearm blood flow but the relative increases were not influenced by concomitant vasoconstriction. Venous compliance was not affected by the infusions, but serotonin and angiotensin II decreased the changes of both forearm volume and venous pressure. ANP antagonized these effects of angiotensin II. Capillary filtration rate was not affected by ANP infusion. ANP alone had no effect on the maximum venous outflow, but it attenuated the decrease induced by norepinephrine and angiotensin II. These results indicate that in the human forearm ANP has predominantly arterial effects, whereas the venous actions become manifest only in the presence of vasoconstriction. The venous effect of ANP may therefore gain importance in disease states with elevated levels of vasoconstrictors, for instance, in congestive heart failure.

Adult↗
PubMed1990

Covalent immobilization of proteins and peptides for solid-phase sequencing using prepacked capillary columns.

The use of prepacked capillary columns for immobilizing proteins and peptides for solid-phase Edman degradation is described. Capillary tubes with an internal volume of about 30 microliters are filled with glass beads bearing isothiocyanato groups (DITC-glass), aminophenyl groups (AP-glass), or aminoethylaminopropyl groups (AEAP-glass) and are sealed with porous plugs. Proteins or peptides in appropriate buffers are introduced into the columns by capillary action and are covalently coupled to the glass beads, either by reaction of lysine side-chain amino groups with DITC-glass, by carbodi-imide-mediated reaction of carboxyl groups with AP-glass, or by reaction of homoserine lactone groups with AEAP-glass. Optimization of attachment conditions is described. The capillary columns are loaded into the sequencer and, when sequencing has been completed, are discarded. This technique greatly simplifies polypeptide immobilization and is suitable for microsequencing (less than 50-1000 pmol) or macrosequencing (1-50 nmol).

Amino Acid Sequence↗
PubMed2005

MRA image segmentation with capillary active contour.

Precise segmentation of three-dimensional (3D) magnetic resonance angiography (MRA) image can be a very useful computer aided diagnosis (CAD) tool in clinical routines. Our objective is to develop a specific segmentation scheme for accurately extracting vasculature from MRA images. Our proposed algorithm, called the capillary active contour (CAC), models capillary action where liquid can climb along the boundaries of thin tubes. The CAC, which is implemented based on level sets, is able to segment thin vessels and has been applied for verification on synthetic volumetric images and real 3D MRA images. Compared with other state-of-the-art MRA segmentation algorithms, our experiments show that the introduced capillary force can facilitate more accurate segmentation of blood vessels.

Algorithms↗
PubMed2005

Novel capillary channel fiber scaffolds for guided tissue engineering.

A novel type of capillary channel fibers (CCFs) containing eight open grooves with depth of 5-15 microm and width of 10 microm were tested for their use in tissue engineering as matrices that provide topographical guidance to neo-tissue development. The matrices fabricated from fibers of poly(l-lactic acid) (PLA) and polyethylene terephthalate (PET) were seeded with rat skin fibroblasts (RSFs) and rat aortic smooth muscle cells (RASMCs) for up to 4 weeks. Cells attached and extended their cytoplasmic lamellapodia within the grooves. The cells were proliferating within the grooves and were highly aligned parallel to the direction of the grooves. RASMCs and RSFs showed highly aligned actin and vimentin cytoskeleton, respectively. The cells also deposited extracellular matrix proteins such as laminin and collagen within the grooves parallel to the groove direction. These CCFs also have the unique ability to move fluids instantaneously by capillary action, thus, have the potential to transport oxygen and nutrients deep within the scaffolds. Such CCF matrices would be useful for creating highly organized tissues such as tendon, ligament, nerve, and cardiac muscle.

Animals↗
PubMed1983

The role of skeletal blood flow in determining the uptake of 99mTc-methylene diphosphonate.

The increased uptake of bone-seeking radionuclides following a fracture has been stated to be due to an increase in bone blood flow, resulting in an increase in capillary surface area available for exchange. This paper examines the relationship between the maximum instantaneous extraction of 99mTc-MDP and blood flow in normal canine tibia. The findings, consistent with the model of capillary action proposed for muscle by Renkin and Crone, are applicable to bone. There is no evidence that in normal bone the surface area available for exchange responds to an increase in bone blood flow.

Animals↗
PubMedDate not supplied

Further experience with a capillary tube pregnancy test.

Further evaluation of the nonrefrigerated capillary tube pregnancy test is presented. A 127-mm by 2-mm glass capillary tube containing lyophilized antibody to human chorionic gonadotropin and latex indicator particles is used. Urine is drawn into the tube by capillary action; then, the tube is tilted to allow the urine to dissolve the antibody and to suspend the latex particles. The test results are read after a one-hour incubation period. Test results were evaluated against histopathologic and clinical data. Special efforts were made to stress the false-positive rate of the test by tripling the number of negative cases and doubling the sample size. A 99.82% agreement, a 0.18% false-negative rate and a 0% false-positive rate were obtained. In 52 confirmed pregnancies, the more sensitive capillary test detected human chorionic gonadotropin, whereas the commercial tests did not. Human chorionic gonadotropin was also detected one week earlier than reported in the first series.

Antibodies↗