Multiplexed fluorescence detector system for capillary electrophoresis

DOEpatents

Yeung, Edward S.; Taylor, John A.

1996-03-12

A fluorescence detection system for capillary electrophoresis is provided wherein the detection system can simultaneously excite fluorescence and substantially simultaneously monitor separations in multiple capillaries. This multiplexing approach involves laser irradiation of a sample in a plurality of capillaries through optical fibers that are coupled individually with the capillaries. The array is imaged orthogonally through a microscope onto a charge-coupled device camera for signal analysis.

Multiplexed fluorescence detector system for capillary electrophoresis

DOEpatents

Yeung, Edward S.; Taylor, John A.

1994-06-28

A fluorescence detection system for capillary electrophoresis is provided wherein the detection system can simultaneously excite fluorescence and substantially simultaneously monitor separations in multiple capillaries. This multiplexing approach involves laser irradiation of a sample in a plurality of capillaries through optical fibers that are coupled individually with the capillaries. The array is imaged orthogonally through a microscope onto a charge-coupled device camera for signal analysis.

Multiplexed fluorescence detector system for capillary electrophoresis

DOEpatents

Yeung, E.S.; Taylor, J.A.

1996-03-12

A fluorescence detection system for capillary electrophoresis is provided wherein the detection system can simultaneously excite fluorescence and substantially simultaneously monitor separations in multiple capillaries. This multiplexing approach involves laser irradiation of a sample in a plurality of capillaries through optical fibers that are coupled individually with the capillaries. The array is imaged orthogonally through a microscope onto a charge-coupled device camera for signal analysis. 14 figs.

Multiplexed fluorescence detector system for capillary electrophoresis

DOEpatents

Yeung, E.S.; Taylor, J.A.

1994-06-28

A fluorescence detection system for capillary electrophoresis is provided wherein the detection system can simultaneously excite fluorescence and substantially simultaneously monitor separations in multiple capillaries. This multiplexing approach involves laser irradiation of a sample in a plurality of capillaries through optical fibers that are coupled individually with the capillaries. The array is imaged orthogonally through a microscope onto a charge-coupled device camera for signal analysis. 14 figures.

Fatal Primary Capillary Leak Syndrome in a Late Preterm Newborn.

PubMed

Kulihova, Katarina; Prochazkova, Martina; Semberova, Jana; Janota, Jan

2016-10-01

Primary capillary leak syndrome is a rare disease of unknown etiology, characterized by episodes of vascular collapse and plasma extravasation, which may lead to multiple organ failure. Primary capillary leak is extremely rare in children. The authors report a case of a late preterm newborn with fatal capillary leak syndrome of unknown etiology, manifesting as hypotension unresponsive to treatment, extravasation leading to generalised edema, disseminated intravascular coagulation and finally, multiple organ dysfunction syndrome. Aggressive volumotherapy and a combination of inotropes and high doses of terlipressin did not influence systemic vascular collapse and plasma extravasation. The newborn developed multiple organ failure and died on day 27 of life. Investigations performed failed to reveal any specific cause of capillary leak. This is the first report of a fatal primary capillary leak syndrome in a newborn.

Fabrication of a miniaturized capillary waveguide integrated fiber-optic sensor for fluoride determination.

PubMed

Xiong, Yan; Wang, Chengjie; Tao, Tao; Duan, Ming; Tan, Jun; Wu, Jiayi; Wang, Dong

2016-05-10

Fluoride concentration is a key aspect of water quality and essential for human health. Too much or too little fluoride intake from water supplies is harmful to public health. In this study, a capillary waveguide integrated fiber-optic sensor was fabricated for fluoride measurement in water samples. The sensor was modularly designed with three parts, i.e., a light source, capillary flow cell and detector. When light propagated from a light emitting diode (LED) to the capillary waveguide cell through an excitation fiber, it interacted with the sensing reagent, and its intensity changed with different fluoride concentrations. Then, the light propagated to the detector through a detection fiber for absorption determination of fluoride according to Beer's law. This miniaturized sensor showed advantages of fast analysis (9.2 s) and small reagent demand (200 μL) per sample, and it also had a low detection limit (8 ppb) and high selectivity for fluoride determination. The sensor was applied to fluoride determination in different water samples. The results obtained were compared with those obtained by conventional spectrophotometry and ion chromatography, showing agreement and validating the sensor's potential application.

Integrated microfluidic chip for rapid DNA digestion and time-resolved capillary electrophoresis analysis

PubMed Central

Lin, Che-Hsin; Wang, Yao-Nan; Fu, Lung-Ming

2012-01-01

An integrated microfluidic chip is proposed for rapid DNA digestion and time-resolved capillary electrophoresis (CE) analysis. The chip comprises two gel-filled chambers for DNA enrichment and purification, respectively, a T-form micromixer for DNA/restriction enzyme mixing, a serpentine channel for DNA digestion reaction, and a CE channel for on-line capillary electrophoresis analysis. The DNA and restriction enzyme are mixed electroomostically using a pinched-switching DC field. The experimental and numerical results show that a mixing performance of 97% is achieved within a distance of 1 mm from the T-junction when a driving voltage of 90 V/cm and a switching frequency of 4 Hz are applied. Successive mixing digestion and capillary electrophoresis operation clearly present the changes on digesting φx-174 DNA in different CE runs. The time-resolved electropherograms show that the proposed device enables a φx-174 DNA sample comprising 11 fragments to be concentrated and analyzed within 24 min. Overall, the results presented in this study show that the proposed microfluidic chip provides a rapid and effective tool for DNA digestion and CE analysis applications. PMID:22662085

Mathematical Modeling of Loop Heat Pipes with Multiple Capillary Pumps and Multiple Condensers. Part 1; Stead State Stimulations

NASA Technical Reports Server (NTRS)

Hoang, Triem T.; OConnell, Tamara; Ku, Jentung

2004-01-01

Loop Heat Pipes (LHPs) have proven themselves as reliable and robust heat transport devices for spacecraft thermal control systems. So far, the LHPs in earth-orbit satellites perform very well as expected. Conventional LHPs usually consist of a single capillary pump for heat acquisition and a single condenser for heat rejection. Multiple pump/multiple condenser LHPs have shown to function very well in ground testing. Nevertheless, the test results of a dual pump/condenser LHP also revealed that the dual LHP behaved in a complicated manner due to the interaction between the pumps and condensers. Thus it is redundant to say that more research is needed before they are ready for 0-g deployment. One research area that perhaps compels immediate attention is the analytical modeling of LHPs, particularly the transient phenomena. Modeling a single pump/single condenser LHP is difficult enough. Only a handful of computer codes are available for both steady state and transient simulations of conventional LHPs. No previous effort was made to develop an analytical model (or even a complete theory) to predict the operational behavior of the multiple pump/multiple condenser LHP systems. The current research project offered a basic theory of the multiple pump/multiple condenser LHP operation. From it, a computer code was developed to predict the LHP saturation temperature in accordance with the system operating and environmental conditions.

A microfluidic circulatory system integrated with capillary-assisted pressure sensors.

PubMed

Chen, Yangfan; Chan, Ho Nam; Michael, Sean A; Shen, Yusheng; Chen, Yin; Tian, Qian; Huang, Lu; Wu, Hongkai

2017-02-14

The human circulatory system comprises a complex network of blood vessels interconnecting biologically relevant organs and a heart driving blood recirculation throughout this system. Recreating this system in vitro would act as a bridge between organ-on-a-chip and "body-on-a-chip" and advance the development of in vitro models. Here, we present a microfluidic circulatory system integrated with an on-chip pressure sensor to closely mimic human systemic circulation in vitro. A cardiac-like on-chip pumping system is incorporated in the device. It consists of four pumping units and passive check valves, which mimic the four heart chambers and heart valves, respectively. Each pumping unit is independently controlled with adjustable pressure and pump rate, enabling users to control the mimicked blood pressure and heartbeat rate within the device. A check valve is located downstream of each pumping unit to prevent backward leakage. Pulsatile and unidirectional flow can be generated to recirculate within the device by programming the four pumping units. We also report an on-chip capillary-assisted pressure sensor to monitor the pressure inside the device. One end of the capillary was placed in the measurement region, while the other end was sealed. Time-dependent pressure changes were measured by recording the movement of the liquid-gas interface in the capillary and calculating the pressure using the ideal gas law. The sensor covered the physiologically relevant blood pressure range found in humans (0-142.5 mmHg) and could respond to 0.2 s actuation time. With the aid of the sensor, the pressure inside the device could be adjusted to the desired range. As a proof of concept, human normal left ventricular and arterial pressure profiles were mimicked inside this device. Human umbilical vein endothelial cells (HUVECs) were cultured on chip and cells can respond to mechanical forces generated by arterial-like flow patterns.

Spectrometer capillary vessel and method of making same

DOEpatents

Linehan, John C.; Yonker, Clement R.; Zemanian, Thomas S.; Franz, James A.

1995-01-01

The present invention is an arrangement of a glass capillary tube for use in spectroscopy. In particular, the invention is a capillary arranged in a manner permitting a plurality or multiplicity of passes of a sample material through a spectroscopic measurement zone. In a preferred embodiment, the multi-pass capillary is insertable within a standard NMR sample tube. The present invention further includes a method of making the multi-pass capillary tube and an apparatus for spinning the tube.

Spectrometer capillary vessel and method of making same

DOEpatents

Linehan, J.C.; Yonker, C.R.; Zemanian, T.S.; Franz, J.A.

1995-11-21

The present invention is an arrangement of a glass capillary tube for use in spectroscopy. In particular, the invention is a capillary arranged in a manner permitting a plurality or multiplicity of passes of a sample material through a spectroscopic measurement zone. In a preferred embodiment, the multi-pass capillary is insertable within a standard NMR sample tube. The present invention further includes a method of making the multi-pass capillary tube and an apparatus for spinning the tube. 13 figs.

Microfluidic PMMA interfaces for rectangular glass capillaries

NASA Astrophysics Data System (ADS)

Evander, Mikael; Tenje, Maria

2014-02-01

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.

Demonstration of Nautilus Centripetal Capillary Condenser Technology

NASA Technical Reports Server (NTRS)

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.

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

PubMed

Safavieh, Roozbeh; Juncker, David

2013-11-07

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

Electrically controlled microvalves to integrate microchip polymerase chain reaction and capillary electrophoresis.

PubMed

Kaigala, Govind V; Hoang, Viet N; Backhouse, Christopher J

2008-07-01

Microvalves are key in realizing portable miniaturized diagnostic platforms. We present a scalable microvalve that integrates well with standard lab on a chip (LOC) implementations, yet which requires essentially no external infrastructure for its operation. This electrically controlled, phase-change microvalve is used to integrate genetic amplification and analysis via capillary electrophoresis--the basis of many diagnostics. The microvalve is actuated using a polymer (polyethylene glycol, PEG) that exhibits a large volumetric change between its solid and liquid phases. Both the phase change of the PEG and the genetic amplification via polymerase chain reaction (PCR) are thermally controlled using thin film resistive elements that are patterned using standard microfabrication methods. By contrast with many other valve technologies, these microvalves and their control interface scale down in size readily. The novelty here lies in the use of fully integrated microvalves that require only electrical connections to realize a portable and inexpensive genetic analysis platform.

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

PubMed Central

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

Integrated optical detection of autonomous capillary microfluidic immunoassays:a hand-held point-of-care prototype.

PubMed

Novo, P; Chu, V; Conde, J P

2014-07-15

The miniaturization of biosensors using microfluidics has potential in enabling the development of point-of-care devices, with the added advantages of reduced time and cost of analysis with limits-of-detection comparable to those obtained through traditional laboratory techniques. Interfacing microfluidic devices with the external world can be difficult especially in aspects involving fluid handling and the need for simple sample insertion that avoids special equipment or trained personnel. In this work we present a point-of-care prototype system by integrating capillary microfluidics with a microfabricated photodiode array and electronic instrumentation into a hand-held unit. The capillary microfluidic device is capable of autonomous and sequential fluid flow, including control of the average fluid velocity at any given point of the analysis. To demonstrate the functionality of the prototype, a model chemiluminescence ELISA was performed. The performance of the integrated optical detection in the point-of-care prototype is equal to that obtained with traditional bench-top instrumentation. The photodiode signals were acquired, displayed and processed by a simple graphical user interface using a computer connected to the microcontroller through USB. The prototype performed integrated chemiluminescence ELISA detection in about 15 min with a limit-of-detection of ≈2 nM with an antibody-antigen affinity constant of ≈2×10(7) M(-1). Copyright © 2014 Elsevier B.V. All rights reserved.

Double emulsions from a capillary array injection microfluidic device.

PubMed

Shang, Luoran; Cheng, Yao; Wang, Jie; Ding, Haibo; Rong, Fei; Zhao, Yuanjin; Gu, Zhongze

2014-09-21

A facile microfluidic device was developed by inserting an annular capillary array into a collection channel for single-step emulsification of double emulsions. By inserting multiple inner-phase solutions into the capillary array, multicomponent double emulsions or microcapsules with inner droplets of different content could also be obtained from the device.

Affinity monolith-integrated poly(methyl methacrylate) microchips for on-line protein extraction and capillary electrophoresis.

PubMed

Sun, Xiuhua; Yang, Weichun; Pan, Tao; Woolley, Adam T

2008-07-01

Immunoaffinity monolith pretreatment columns have been coupled with capillary electrophoresis separation in poly(methyl methacrylate) (PMMA) microchips. Microdevices were designed with eight reservoirs to enable the electrically controlled transport of selected analytes and solutions to carry out integrated immunoaffinity extraction and electrophoretic separation. The PMMA microdevices were fabricated reproducibly and with high fidelity by solvent imprinting and thermal bonding methods. Monoliths with epoxy groups for antibody immobilization were prepared by direct in situ photopolymerization of glycidyl methacrylate and ethylene glycol dimethacrylate in a porogenic solvent consisting of 70% 1-dodecanol and 30% cyclohexanol. Antifluorescein isothiocyanate was utilized as a model affinity group in the monoliths, and the immobilization process was optimized. A mean elution efficiency of 92% was achieved for the monolith-based extraction of fluorescein isothiocyanate (FITC)-tagged human serum albumin. FITC-tagged proteins were purified from a contaminant protein and then separated electrophoretically using these devices. The developed immunoaffinity column/capillary electrophoresis microdevices show great promise for combining sample pretreatment and separation in biomolecular analysis.

Affinity Monolith-Integrated Poly(methyl Methacrylate) Microchips for On-Line Protein Extraction and Capillary Electrophoresis

PubMed Central

Sun, Xiuhua; Yang, Weichun; Pan, Tao; Woolley, Adam T.

2008-01-01

Immunoaffinity monolith pretreatment columns have been coupled with capillary electrophoresis separation in poly(methyl methacrylate) (PMMA) microchips. Microdevices were designed with 8 reservoirs to enable the electrically controlled transport of selected analytes and solutions to carry out integrated immunoaffinity extraction and electrophoretic separation. The PMMA microdevices were fabricated reproducibly and with high fidelity by solvent imprinting and thermal bonding methods. Monoliths with epoxy groups for antibody immobilization were prepared by direct in-situ photopolymerization of glycidyl methacrylate and ethylene dimethacrylate in a porogenic solvent consisting of 70% dodecanol and 30% hexanol. Anti-fluorescein isothiocyanate (FITC) was utilized as a model affinity group in the monoliths, and the immobilization process was optimized. A mean elution efficiency of 92% was achieved for the monolith-based extraction of FITC-tagged human serum albumin. FITC-tagged proteins were purified from a contaminant protein and then separated electrophoretically using these devices. The developed immunoaffinity column/capillary electrophoresis microdevices show great promise for combining sample pretreatment and separation in biomolecular analysis. PMID:18479142

Capillary leak syndrome: etiologies, pathophysiology, and management.

PubMed

Siddall, Eric; Khatri, Minesh; Radhakrishnan, Jai

2017-07-01

In various human diseases, an increase in capillary permeability to proteins leads to the loss of protein-rich fluid from the intravascular to the interstitial space. Although sepsis is the disease most commonly associated with this phenomenon, many other diseases can lead to a "sepsis-like" syndrome with manifestations of diffuse pitting edema, exudative serous cavity effusions, noncardiogenic pulmonary edema, hypotension, and, in some cases, hypovolemic shock with multiple-organ failure. The term capillary leak syndrome has been used to describe this constellation of disease manifestations associated with an increased capillary permeability to proteins. Diseases other than sepsis that can result in capillary leak syndrome include the idiopathic systemic capillary leak syndrome or Clarkson's disease, engraftment syndrome, differentiation syndrome, the ovarian hyperstimulation syndrome, hemophagocytic lymphohistiocytosis, viral hemorrhagic fevers, autoimmune diseases, snakebite envenomation, and ricin poisoning. Drugs including some interleukins, some monoclonal antibodies, and gemcitabine can also cause capillary leak syndrome. Acute kidney injury is commonly seen in all of these diseases. In addition to hypotension, cytokines are likely to be important in the pathophysiology of acute kidney injury in capillary leak syndrome. Fluid management is a critical part of the treatment of capillary leak syndrome; hypovolemia and hypotension can cause organ injury, whereas capillary leakage of administered fluid can worsen organ edema leading to progressive organ injury. The purpose of this article is to discuss the diseases other than sepsis that produce capillary leak and review their collective pathophysiology and treatment. Copyright © 2017 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.

Integrating Internal Standards into Disposable Capillary Electrophoresis Devices To Improve Quantification

PubMed Central

2017-01-01

To improve point-of-care quantification using microchip capillary electrophoresis (MCE), the chip-to-chip variabilities inherent in disposable, single-use devices must be addressed. This work proposes to integrate an internal standard (ISTD) into the microchip by adding it to the background electrolyte (BGE) instead of the sample—thus eliminating the need for additional sample manipulation, microchip redesigns, and/or system expansions required for traditional ISTD usage. Cs and Li ions were added as integrated ISTDs to the BGE, and their effects on the reproducibility of Na quantification were explored. Results were then compared to the conclusions of our previous publication which used Cs and Li as traditional ISTDs. The in-house fabricated microchips, electrophoretic protocols, and solution matrixes were kept constant, allowing the proposed method to be reliably compared to the traditional method. Using the integrated ISTDs, both Cs and Li improved the Na peak area reproducibility approximately 2-fold, to final RSD values of 2.2–4.7% (n = 900). In contrast (to previous work), Cs as a traditional ISTD resulted in final RSDs of 2.5–8.8%, while the traditional Li ISTD performed poorly with RSDs of 6.3–14.2%. These findings suggest integrated ISTDs are a viable method to improve the precision of disposable MCE devices—giving matched or superior results to the traditional method in this study while neither increasing system cost nor complexity. PMID:28192985

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

NASA Astrophysics Data System (ADS)

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

2016-09-01

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

Integration of capillary electrophoresis with gold nanoparticle-based colorimetry.

PubMed

Li, Tong; Wu, Zhenglong; Qin, Weidong

2017-12-01

A method integrating capillary electrophoresis (CE) and gold nanoparticle aggregation-based colorimetry (AuNP-ABC) was described. By using a dual-sheath interface, the running buffer was isolated from the colorimetric reaction solution so that CE and AuNP-ABC would not interfere with each other. The proof-of-concept was validated by assay of polyamidoamine (PAMAM) dendrimers that were fortified in human urine samples. The factors influencing the CE-AuNP-ABC performances were investigated and optimized. Under the optimal conditions, the dendrimers were separated within 8 min, with detection limits of 0.5, 1.2 and 2.6 μg mL -1 for PAMAM G1.0, G2.0 and G3.0, respectively. The sensitivity of CE-AuNP-ABC was comparable to or even better than those of liquid chromatography-fluorimetry and liquid chromatography-mass spectrometry. The results suggested that the proposed strategy can be applied to facile and quick determination of analytes of similar properties in complex matrices. Copyright © 2017 Elsevier B.V. All rights reserved.

Flight Testing of the Capillary Pumped Loop 3 Experiment

NASA Technical Reports Server (NTRS)

Ottenstein, Laura; Butler, Dan; Ku, Jentung; Cheung, Kwok; Baldauff, Robert; Hoang, Triem

2002-01-01

The Capillary Pumped Loop 3 (CAPL 3) experiment was a multiple evaporator capillary pumped loop experiment that flew in the Space Shuttle payload bay in December 2001 (STS-108). The main objective of CAPL 3 was to demonstrate in micro-gravity a multiple evaporator capillary pumped loop system, capable of reliable start-up, reliable continuous operation, and heat load sharing, with hardware for a deployable radiator. Tests performed on orbit included start-ups, power cycles, low power tests (100 W total), high power tests (up to 1447 W total), heat load sharing, variable/fixed conductance transition tests, and saturation temperature change tests. The majority of the tests were completed successfully, although the experiment did exhibit an unexpected sensitivity to shuttle maneuvers. This paper describes the experiment, the tests performed during the mission, and the test results.

An integrated passive micromixer-magnetic separation-capillary electrophoresis microdevice for rapid and multiplex pathogen detection at the single-cell level.

PubMed

Jung, Jae Hwan; Kim, Gha-Young; Seo, Tae Seok

2011-10-21

Here we report an integrated microdevice consisting of an efficient passive mixer, a magnetic separation chamber, and a capillary electrophoretic microchannel in which DNA barcode assay, target pathogen separation, and barcode DNA capillary electrophoretic analysis were performed sequentially within 30 min for multiplex pathogen detection at the single-cell level. The intestine-shaped serpentine 3D micromixer provides a high mixing rate to generate magnetic particle-pathogenic bacteria-DNA barcode labelled AuNP complexes quantitatively. After magnetic separation and purification of those complexes, the barcode DNA strands were released and analyzed by the microfluidic capillary electrophoresis within 5 min. The size of the barcode DNA strand was controlled depending on the target bacteria (Staphylococcus aureus, Escherichia coli O157:H7, and Salmonella typhimurium), and the different elution time of the barcode DNA peak in the electropherogram allows us to recognize the target pathogen with ease in the monoplex as well as in the multiplex analysis. In addition, the quantity of the DNA barcode strand (∼10(4)) per AuNP is enough to be observed in the laser-induced confocal fluorescence detector, thereby making single-cell analysis possible. This novel integrated microdevice enables us to perform rapid, sensitive, and multiplex pathogen detection with sample-in-answer-out capability to be applied for biosafety testing, environmental screening, and clinical trials.

Enhanced flow boiling in microchannels through integrating multiple micro-nozzles and reentry microcavities

NASA Astrophysics Data System (ADS)

Li, Wenming; Qu, Xiaopeng; Alam, Tamanna; Yang, Fanghao; Chang, Wei; Khan, Jamil; Li, Chen

2017-01-01

In a microchannel system, a higher mass velocity can lead to enhanced flow boiling performances, but at a cost of two-phase pressure drop. It is highly desirable to achieve a high heat transfer rate and critical heat flux (CHF) exceeding 1 kW/cm2 without elevating the pressure drop, particularly, at a reduced mass velocity. In this study, we developed a microchannel configuration that enables more efficient utilization of the coolant through integrating multiple microscale nozzles connected to auxiliary channels as well as microscale reentry cavities on sidewalls of main microchannels. We achieved a CHF of 1016 W/cm2 with a 50% less mass velocity, i.e., 680 kg/m2s, compared to the two-nozzle configuration developed in our previous studies. Two primary enhancement mechanisms are: (a) the enhanced global liquid supply by four evenly distributed micronozzles, particularly near the outlet region and (b) the effective management of local dryout by the capillary flow-induced sustainable thin liquid film resulting from an array of microscale cavities. A significantly improved heat transfer coefficient of 131 kW/m2 K at a mass velocity of 680 kg/m2s is attributed to the enhanced nucleate boiling, the established capillary/thin film evaporation, and the induced advection from the present microchannel configuration. All these significant enhancements have been achieved with a ˜55% lower two-phase pressure drop.

Spinal capillary hemangiomas: Two cases reports and review of the literature

PubMed Central

Tunthanathip, Thara; Rattanalert, Sanguansin; Oearsakul, Thakul; Kanjanapradit, Kanet

2017-01-01

Hemangiomas have rarely been found in the spinal cord. A few cases of spinal capillary hemangioma have been reported since 1987. The authors reported the two cases of capillary hemangioma including the tumor at conus medullaris and the another mimicked von Hippel-Lindau disease. A 15-year-old man was presented with coccydynia and left leg pain. A magnetic resonance imaging (MRI) revealed an intradural extramedullary enhancing mass at conus medullaris. Another case, a 31-year-old man was presented with a history of familial history of brain tumor, retinal hemangioma both eyes, multiple pancreatic cyst and syringobulbia with syringohydromyelia. On MRI, a well-circumscribed intramedullary nodule was detected at C5-6 level and multiple subpial nodule along cervicothoracic spinal cord. All patients underwent surgery, and the histological diagnosis confirmed capillary hemangioma. Although rare and indistinguishable from other tumors, capillary hemangioma should be in the differential diagnosis of the spinal cord tumor. PMID:28761543

Capillary Structures for Exploration Life Support (Capillary Structures)

NASA Image and Video Library

2017-07-10

iss052e013146 (July 10, 2017) --- Astronaut Jack Fischer is photographed during setup of hardware for the Capillary Structures for Exploration Life Support (Capillary Structures) two sorbent demonstrations. The Capillary Structures for Exploration Life Support (Capillary Structures) investigation studies a new method using structures of specific shapes to manage fluid and gas mixtures. The investigation studies water recycling and carbon dioxide removal, benefiting future efforts to design lightweight, more reliable life support systems for future space missions.

Integrating Multiple Intelligences in EFL/ESL Classrooms

ERIC Educational Resources Information Center

Bas, Gokhan

2008-01-01

This article deals with the integration of the theory of Multiple Intelligences in EFL/ESL classrooms. In this study, after the theory of multiple intelligences was presented shortly, the integration of this theory into English classrooms. Intelligence types in MI Theory were discussed and some possible application ways of these intelligence types…

A simulation model of the oxygen alveolo-capillary exchange in normal and pathological conditions.

PubMed

Brighenti, Chiara; Gnudi, Gianni; Avanzolini, Guido

2003-05-01

This paper presents a mathematical model of the oxygen alveolo-capillary exchange to provide the capillary oxygen partial pressure profile in normal and pathological conditions. In fact, a thickening of the blood-gas barrier, heavy exercise or a low oxygen partial pressure (PO2) in the alveolar space can reduce the O2 alveolo-capillary exchange. Since the reversible binding between haemoglobin and oxygen makes it impossible to determine the closed form for the mathematical description of the PO2 profile along the pulmonary capillaries, an approximate analytical solution of the capillary PO2 profile is proposed. Simulation results are compared with the capillary PO2 profile obtained by numerical integration and by a piecewise linear interpolation of the oxyhaemoglobin dissociation curve. Finally, the proposed model is evaluated in a large range of physiopathological diffusive conditions. The good fit to numerical solutions in all experimental conditions seems to represent a substantial improvement with respect to the approach based on a linear approximation of the oxyhaemoglobin dissociation curve, and makes this model a candidate to be incorporated into the integrated descriptions of the entire respiratory system, where the datum of primary interest is the value of end capillary PO2.

Charging YOYO-1 on Capillary Wall for Online DNA Intercalation and Integrating This Approach with Multiplex PCR and Bare Narrow Capillary–Hydrodynamic Chromatography for Online DNA Analysis

PubMed Central

2016-01-01

Multiplex polymerase chain reaction (PCR) has been widely utilized for high-throughput pathogen identification. Often, a dye is used to intercalate the amplified DNA fragments, and identifications of the pathogens are carried out by DNA melting curve analysis or gel electrophoresis. Integrating DNA amplification and identification is a logic path toward maximizing the benefit of multiplex PCR. Although PCR and gel electrophoresis have been integrated, replenishing the gels after each run is tedious and time-consuming. In this technical note, we develop an approach to address this issue. We perform multiplex PCR inside a capillary, transfer the amplified fragments to a bare narrow capillary, and measure their lengths online using bare narrow capillary–hydrodynamic chromatography (BaNC-HDC), a new technique recently developed in our laboratory for free-solution DNA separation. To intercalate the DNA with YOYO-1 (a fluorescent dye) for BaNC-HDC, we flush the capillary column with a YOYO-1 solution; positively charged YOYO-1 is adsorbed (or charged) onto the negatively charged capillary wall. As DNA molecules are driven down the column for separation, they react with the YOYO-1 stored on the capillary wall and are online-intercalated with the dye. With a single YOYO-1 charging, the column can be used for more than 40 runs, although the fluorescence signal intensities of the DNA peaks decrease gradually. Although the dye-DNA intercalation occurs during the separation, it does not affect the retention times, separation efficiencies, or resolutions. PMID:25555111

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

PubMed Central

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

Integrated circuit-based instrumentation for microchip capillary electrophoresis.

PubMed

Behnam, M; Kaigala, G V; Khorasani, M; Martel, S; Elliott, D G; Backhouse, C J

2010-09-01

Although electrophoresis with laser-induced fluorescence (LIF) detection has tremendous potential in lab on chip-based point-of-care disease diagnostics, the wider use of microchip electrophoresis has been limited by the size and cost of the instrumentation. To address this challenge, the authors designed an integrated circuit (IC, i.e. a microelectronic chip, with total silicon area of <0.25 cm2, less than 5 mmx5 mm, and power consumption of 28 mW), which, with a minimal additional infrastructure, can perform microchip electrophoresis with LIF detection. The present work enables extremely compact and inexpensive portable systems consisting of one or more complementary metal-oxide-semiconductor (CMOS) chips and several other low-cost components. There are, to the authors' knowledge, no other reports of a CMOS-based LIF capillary electrophoresis instrument (i.e. high voltage generation, switching, control and interface circuit combined with LIF detection). This instrument is powered and controlled using a universal serial bus (USB) interface to a laptop computer. The authors demonstrate this IC in various configurations and can readily analyse the DNA produced by a standard medical diagnostic protocol (end-labelled polymerase chain reaction (PCR) product) with a limit of detection of approximately 1 ng/microl (approximately 1 ng of total DNA). The authors believe that this approach may ultimately enable lab-on-a-chip-based electrophoretic instruments that cost on the order of several dollars.

Automation and integration of multiplexed on-line sample preparation with capillary electrophoresis for DNA sequencing

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

Tan, H.

1999-03-31

The purpose of this research is to develop a multiplexed sample processing system in conjunction with multiplexed capillary electrophoresis for high-throughput DNA sequencing. The concept from DNA template to called bases was first demonstrated with a manually operated single capillary system. Later, an automated microfluidic system with 8 channels based on the same principle was successfully constructed. The instrument automatically processes 8 templates through reaction, purification, denaturation, pre-concentration, injection, separation and detection in a parallel fashion. A multiplexed freeze/thaw switching principle and a distribution network were implemented to manage flow direction and sample transportation. Dye-labeled terminator cycle-sequencing reactions are performedmore » in an 8-capillary array in a hot air thermal cycler. Subsequently, the sequencing ladders are directly loaded into a corresponding size-exclusion chromatographic column operated at {approximately} 60 C for purification. On-line denaturation and stacking injection for capillary electrophoresis is simultaneously accomplished at a cross assembly set at {approximately} 70 C. Not only the separation capillary array but also the reaction capillary array and purification columns can be regenerated after every run. DNA sequencing data from this system allow base calling up to 460 bases with accuracy of 98%.« less

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

PubMed

Riesberg, Jeremiah J; Shen, Wei

2015-09-01

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

Capillary descent.

PubMed

Delannoy, Joachim; de Maleprade, Hélène; Clanet, Christophe; Quéré, David

2018-05-31

A superhydrophobic capillary tube immersed in water and brought in contact with the bath surface will be invaded by air, owing to its aerophilicity. We discuss this phenomenon where the ingredients of classical capillary rise are inverted, which leads to noticeable dynamical features. (1) The main regime of air invasion is linear in time, due to the viscous resistance of water. (2) Menisci in tubes with millimetre-size radii strongly oscillate before reaching their equilibrium depth, a consequence of inertia. On the whole, capillary descent provides a broad variety of dynamics where capillary effects, viscous friction and liquid inertia all play a role.

Monolithic Integration of Two-Dimensional Liquid Chromatography-Capillary Electrophoresis and Electrospray Ionization on a Microfluidic Device

PubMed Central

Chambers, Andrew G.; Mellors, J. Scott; Henley, W. Hampton; Ramsey, J. Michael

2011-01-01

A microfluidic device capable of two-dimensional reversed-phase liquid chromatography-capillary electrophoresis with integrated electrospray ionization (LC-CE-ESI) for mass spectrometry (MS)-based proteomic applications is described. Traditional instrumentation was used for the LC sample injection and delivery of the LC mobile phase. The glass microfabricated device incorporated a sample-trapping region and an LC channel packed with reversed-phase particles. Rapid electrokinetic injections of the LC effluent into the CE dimension were performed at a cross channel intersection. The CE separation channel terminated at a corner of the square device, which functioned as an integrated electrospray tip. In addition to LC-CE-ESI, this device was used for LC-ESI without any instrumental modifications. To evaluate the system, LC-MS and LC-CE-MS analysis of protein digests were performed and compared. PMID:21214194

Time resolved EUV spectra from Zpinching capillary discharge plasma

NASA Astrophysics Data System (ADS)

Jancarek, Alexandr; Nevrkla, Michal; Nawaz, Fahad

2015-09-01

We developed symmetrically charged driver to obtain high voltage, high current Z-pinching capillary discharge. Plasma is created by up to 70 kA, 29 ns risetime current pulse passing through a 5 mm inner diameter, 224 mm long capillary filled with gas to initial pressure in the range of 1 kPa. Due to the low inductance design of the driver, the pinch is observable directly from the measured current curve. Time-integrated and time-resolved spectra of discharge plasma radiation are recorded together with the capillary current and analyzed. The most encouraging spectra were captured in the wavelength range 8.3 ÷ 14 nm. This spectral region contains nitrogen Balmer series lines including potentially lasing NVII 2 - 3 transition. Spectral lines are identified in the NIST database using the FLY kinetic code. The line of 13.38 nm wavelength, transition NVII 2 - 3, was observed in gated, and also in time-integrated spectra for currents >60 kA. This work has been supported by the Ministry of Education, Youth and Sports of the Czech Republic grants LG13029.

On the performance of capillary barriers as landfill cover

NASA Astrophysics Data System (ADS)

Kämpf, M.; Montenegro, H.

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

Encapsulation of Fluidic Tubing and Microelectrodes in Microfluidic Devices: Integrating Off-Chip Process and Coupling Conventional Capillary Electrophoresis with Electrochemical Detection

PubMed Central

Becirovic, Vedada; Doonan, Steven R.; Martin, R. Scott

2013-01-01

In this paper, an approach to fabricate epoxy or polystyrene microdevices with encapsulated tubing and electrodes is described. Key features of this approach include a fixed alignment between the fluidic tubing and electrodes, the ability to polish the device when desired, and the low dead volume nature of the fluidic interconnects. It is shown that a variety of tubing can be encapsulated with this approach, including fused silica capillary, polyetheretherketone (PEEK), and perfluoroalkoxy (PFA), with the resulting tubing/microchip interface not leading to significant band broadening or plug dilution. The applicability of the devices with embedded tubing is demonstrated by integrating several off-chip analytical methods to the microchip. This includes droplet transfer, droplet desegmentation, and microchip-based flow injection analysis. Off-chip generated droplets can be transferred to the microchip with minimal coalescence, while flow injection studies showed improved peak shape and sensitivity when compared to the use of fluidic interconnects with an appreciable dead volume. Importantly, it is shown that this low dead volume approach can be extended to also enable the integration of conventional capillary electrophoresis (CE) with electrochemical detection. This is accomplished by embedding fused silica capillary along with palladium (for grounding the electrophoresis voltage) and platinum (for detection) electrodes. With this approach, up to 128,000 theoretical plates for dopamine was possible. In all cases, the tubing and electrodes are housed in a rigid base; this results in extremely robust devices that will be of interest to researchers wanting to develop microchips for use by non-experts. PMID:24159363

Encapsulation of Fluidic Tubing and Microelectrodes in Microfluidic Devices: Integrating Off-Chip Process and Coupling Conventional Capillary Electrophoresis with Electrochemical Detection.

PubMed

Becirovic, Vedada; Doonan, Steven R; Martin, R Scott

2013-08-21

In this paper, an approach to fabricate epoxy or polystyrene microdevices with encapsulated tubing and electrodes is described. Key features of this approach include a fixed alignment between the fluidic tubing and electrodes, the ability to polish the device when desired, and the low dead volume nature of the fluidic interconnects. It is shown that a variety of tubing can be encapsulated with this approach, including fused silica capillary, polyetheretherketone (PEEK), and perfluoroalkoxy (PFA), with the resulting tubing/microchip interface not leading to significant band broadening or plug dilution. The applicability of the devices with embedded tubing is demonstrated by integrating several off-chip analytical methods to the microchip. This includes droplet transfer, droplet desegmentation, and microchip-based flow injection analysis. Off-chip generated droplets can be transferred to the microchip with minimal coalescence, while flow injection studies showed improved peak shape and sensitivity when compared to the use of fluidic interconnects with an appreciable dead volume. Importantly, it is shown that this low dead volume approach can be extended to also enable the integration of conventional capillary electrophoresis (CE) with electrochemical detection. This is accomplished by embedding fused silica capillary along with palladium (for grounding the electrophoresis voltage) and platinum (for detection) electrodes. With this approach, up to 128,000 theoretical plates for dopamine was possible. In all cases, the tubing and electrodes are housed in a rigid base; this results in extremely robust devices that will be of interest to researchers wanting to develop microchips for use by non-experts.

Critical Velocities in Open Capillary Flow

NASA Technical Reports Server (NTRS)

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

1996-01-01

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

Regulation of skeletal muscle capillary growth in exercise and disease.

PubMed

Haas, Tara L; Nwadozi, Emmanuel

2015-12-01

Capillaries, which are the smallest and most abundant type of blood vessel, form the primary site of gas, nutrient, and waste transfer between the vascular and tissue compartments. Skeletal muscle exhibits the capacity to generate new capillaries (angiogenesis) as an adaptation to exercise training, thus ensuring that the heightened metabolic demand of the active muscle is matched by an improved capacity for distribution of gases, nutrients, and waste products. This review summarizes the current understanding of the regulation of skeletal muscle capillary growth. The multi-step process of angiogenesis is coordinated through the integration of a diverse array of signals associated with hypoxic, metabolic, hemodynamic, and mechanical stresses within the active muscle. The contributions of metabolic and mechanical factors to the modulation of key pro- and anti-angiogenic molecules are discussed within the context of responses to a single aerobic exercise bout and short-term and long-term training. Finally, the paradoxical lack of angiogenesis in peripheral artery disease and diabetes and the implications for disease progression and muscle health are discussed. Future studies that emphasize an integrated analysis of the mechanisms that control skeletal muscle capillary growth will enable development of targeted exercise programs that effectively promote angiogenesis in healthy individuals and in patient populations.

One-step multiple component isolation from the oil of Crinitaria tatarica (Less.) Sojak. by preparative capillary gas with characterization by spectroscopic and spectrometric techniques and evaluation of biological activity

USDA-ARS?s Scientific Manuscript database

In the present work multiple component isolation from the oil of Crinitaria tatarica (Less.) Sojak. by Preparative Capillary Gas Chromatography (PCGC) with characterization by mass spectrometry (MS) and nuclear magnetic resonance (NMR) spectroscopy have been carried out. Gas chromatography (GC-FID) ...

Increased capillary permeability mediated by a dengue virus-induced lymphokine.

PubMed Central

Khanna, M; Chaturvedi, U C; Sharma, M C; Pandey, V C; Mathur, A

1990-01-01

The mechanism of increased capillary permeability, seen in cases of dengue haemorrhagic fever (DHF) and dengue shock syndrome (DSS), is not known. Dengue type 2 virus (DV) is known to induce production of a lymphokine, the cytotoxic factor (CF), by the T lymphocytes of mouse spleen. The data presented here show that intraperitoneal inoculation of CF in mice results in increased capillary permeability in a dose-dependent manner, as shown by leakage of intravenously injected radiolabelled iodine (125I) or Evans blue dye. Peak leakage occurred 30 min after inoculation of CF and the vascular integrity was restored by 2 hr. The increase in capillary permeability was abrogated by pretreatment of mice with anti-CF antibodies, avil (H1 receptor blocker) or ranitidine (H2 receptor blocker). The findings thus show that a DV-induced lymphokine, the CF, increases the capillary permeability via release of histamine. PMID:2312168

Bayesian correlated clustering to integrate multiple datasets

PubMed Central

Kirk, Paul; Griffin, Jim E.; Savage, Richard S.; Ghahramani, Zoubin; Wild, David L.

2012-01-01

Motivation: The integration of multiple datasets remains a key challenge in systems biology and genomic medicine. Modern high-throughput technologies generate a broad array of different data types, providing distinct—but often complementary—information. We present a Bayesian method for the unsupervised integrative modelling of multiple datasets, which we refer to as MDI (Multiple Dataset Integration). MDI can integrate information from a wide range of different datasets and data types simultaneously (including the ability to model time series data explicitly using Gaussian processes). Each dataset is modelled using a Dirichlet-multinomial allocation (DMA) mixture model, with dependencies between these models captured through parameters that describe the agreement among the datasets. Results: Using a set of six artificially constructed time series datasets, we show that MDI is able to integrate a significant number of datasets simultaneously, and that it successfully captures the underlying structural similarity between the datasets. We also analyse a variety of real Saccharomyces cerevisiae datasets. In the two-dataset case, we show that MDI’s performance is comparable with the present state-of-the-art. We then move beyond the capabilities of current approaches and integrate gene expression, chromatin immunoprecipitation–chip and protein–protein interaction data, to identify a set of protein complexes for which genes are co-regulated during the cell cycle. Comparisons to other unsupervised data integration techniques—as well as to non-integrative approaches—demonstrate that MDI is competitive, while also providing information that would be difficult or impossible to extract using other methods. Availability: A Matlab implementation of MDI is available from http://www2.warwick.ac.uk/fac/sci/systemsbiology/research/software/. Contact: D.L.Wild@warwick.ac.uk Supplementary information: Supplementary data are available at Bioinformatics online. PMID

Capillaries for use in a multiplexed capillary electrophoresis system

DOEpatents

Yeung, Edward S.; Chang, Huan-Tsang; Fung, Eliza 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.

Capillaries for use in a multiplexed capillary electrophoresis system

DOEpatents

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.

Functional integration of PCR amplification and capillary eletrophoresis in a microfabricated DNA analysis device

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

Woolley, A.T.; deMello, A.J.; Mathies, R.A.

Microfabricated silicon PCR reactors and glass capillary electrophoresis (CE) chips have been successfully coupled to form an integrated DNA analysis system. This construct combines the rapid thermal cycling capabilities of microfabricated PCR devices (10{degree}C/s heating, 2.5{degree}C/s cooling) with the high-speed (<120 s) DNA separations provided by microfabricated CE chips. The PCR chamber and the CE chip were directly linked through a photolithographically fabricated channel filled with hydroxyethylcellulose sieving matrix. Electrophoretic injection directly from the PCR chamber through the cross injection channel was used as an `electrophoretic valve` to couple the PCR and CE devices on-chip. To demonstrate the functionality ofmore » this system, a 15 min PCR amplification of a {Beta}-globin target cloned in m13 was immediately followed by high-speed CE chip separation in under 120 s, providing a rapid PCR-CE analysis in under 20 min. A rapid assay for genomic Salmonella DNA was performed in under 45 min, demonstrating that challenging amplifications of diagnostically interesting targets can also be performed. Real-time monitoring of PCR target amplification in these integrated PCR-CE devices is also feasible. 33 refs., 6 figs.« less

Capillary reference half-cell

DOEpatents

Hall, Stephen H.

1996-01-01

The present invention is a reference half-cell electrode wherein intermingling of test fluid with reference fluid does not affect the performance of the reference half-cell over a long time. This intermingling reference half-cell may be used as a single or double junction submersible or surface reference electrode. The intermingling reference half-cell relies on a capillary tube having a first end open to reference fluid and a second end open to test fluid wherein the small diameter of the capillary tube limits free motion of fluid within the capillary to diffusion. The electrode is placed near the first end of the capillary in contact with the reference fluid. The method of operation of the present invention begins with filling the capillary tube with a reference solution. After closing the first end of the capillary, the capillary tube may be fully submerged or partially submerged with the second open end inserted into test fluid. Since the electrode is placed near the first end of the capillary, and since the test fluid may intermingle with the reference fluid through the second open end only by diffusion, this intermingling capillary reference half-cell provides a stable voltage potential for long time periods.

Capillary reference half-cell

DOEpatents

Hall, S.H.

1996-02-13

The present invention is a reference half-cell electrode wherein intermingling of test fluid with reference fluid does not affect the performance of the reference half-cell over a long time. This intermingling reference half-cell may be used as a single or double junction submersible or surface reference electrode. The intermingling reference half-cell relies on a capillary tube having a first end open to reference fluid and a second end open to test fluid wherein the small diameter of the capillary tube limits free motion of fluid within the capillary to diffusion. The electrode is placed near the first end of the capillary in contact with the reference fluid. The method of operation of the present invention begins with filling the capillary tube with a reference solution. After closing the first end of the capillary, the capillary tube may be fully submerged or partially submerged with the second open end inserted into test fluid. Since the electrode is placed near the first end of the capillary, and since the test fluid may intermingle with the reference fluid through the second open end only by diffusion, this intermingling capillary reference half-cell provides a stable voltage potential for long time periods. 11 figs.

Effect of Capillary Tube’s Shape on Capillary Rising Regime for Viscos Fluids

NASA Astrophysics Data System (ADS)

Soroush, F.; Moosavi, A.

2018-05-01

When properties of the displacing fluid are considered, the rising profile of the penetrating fluid in a capillary tube deviates from its classical Lucas-Washburn profile. Also, shape of capillary tube can affect the rising profile in different aspects. In this article, effect of capillary tube’s shape on the vertical capillary motion in presence of gravity is investigated by considering the properties of the displacing fluid. According to the fact that the differential equation of the capillary rising for a non-simple wall type is very difficult to solve analytically, a finite element simulation model is used for this study. After validation of the simulation model with an experiment that has been done with a simple capillary tube, shape of the capillary tube’s wall is changed in order to understand its effects on the capillary rising and different motion regimes that may appear according to different geometries. The main focus of this article is on the sinusoidal wall shapes and comparing them with a simple wall.

Integrative prescreening in analysis of multiple cancer genomic studies

PubMed Central

2012-01-01

Background In high throughput cancer genomic studies, results from the analysis of single datasets often suffer from a lack of reproducibility because of small sample sizes. Integrative analysis can effectively pool and analyze multiple datasets and provides a cost effective way to improve reproducibility. In integrative analysis, simultaneously analyzing all genes profiled may incur high computational cost. A computationally affordable remedy is prescreening, which fits marginal models, can be conducted in a parallel manner, and has low computational cost. Results An integrative prescreening approach is developed for the analysis of multiple cancer genomic datasets. Simulation shows that the proposed integrative prescreening has better performance than alternatives, particularly including prescreening with individual datasets, an intensity approach and meta-analysis. We also analyze multiple microarray gene profiling studies on liver and pancreatic cancers using the proposed approach. Conclusions The proposed integrative prescreening provides an effective way to reduce the dimensionality in cancer genomic studies. It can be coupled with existing analysis methods to identify cancer markers. PMID:22799431

Capillary device refilling. [liquid rocket propellant tank tests

NASA Technical Reports Server (NTRS)

Blatt, M. H.; Merino, F.; Symons, E. P.

1980-01-01

An analytical and experimental study was conducted dealing with refilling start baskets (capillary devices) with settled fluid. A computer program was written to include dynamic pressure, screen wicking, multiple-screen barriers, standpipe screens, variable vehicle mass for computing vehicle acceleration, and calculation of tank outflow rate and vapor pullthrough height. An experimental apparatus was fabricated and tested to provide data for correlation with the analytical model; the test program was conducted in normal gravity using a scale-model capillary device and ethanol as the test fluid. The test data correlated with the analytical model; the model is a versatile and apparently accurate tool for predicting start basket refilling under actual mission conditions.

Near-infrared laser-induced fluorescence detection in capillary electrophoresis.

PubMed

McWhorter, S; Soper, S A

2000-04-01

As capillary electrophoresis continues to focus on miniaturization, either through reducing column dimensions or situating entire electrophoresis systems on planar chips, advances in detection become necessary to meet the challenges posed by these electrophoresis platforms. The challenges result from the fact that miniaturization requires smaller load volumes, demanding highly sensitive detection. In addition, many times multiple targets must be analyzed simultaneously (multiplexed applications), further complicating detection. Near-infrared (NIR) fluorescence offers an attractive alternative to visible fluorescence for critical applications in capillary electrophoresis due to the impressive limits of detection that can be generated, in part resulting from the low background levels that are observed in the NIR. Advances in instrumentation and fluorogenic labels appropriate for NIR monitoring have led to a growing number of examples of the use of NIR fluorescence in capillary electrophoresis. In this review, we will cover instrumental components used to construct ultrasensitive NIR fluorescence detectors, including light sources and photon transducers. In addition, we will discuss various types of labeling dyes appropriate for NIR fluorescence and finally, we will present several applications that have used NIR fluorescence in capillary electrophoresis, especially for DNA sequencing and fragment analysis.

Multiple methods integration for structural mechanics analysis and design

NASA Technical Reports Server (NTRS)

Housner, J. M.; Aminpour, M. A.

1991-01-01

A new research area of multiple methods integration is proposed for joining diverse methods of structural mechanics analysis which interact with one another. Three categories of multiple methods are defined: those in which a physical interface are well defined; those in which a physical interface is not well-defined, but selected; and those in which the interface is a mathematical transformation. Two fundamental integration procedures are presented that can be extended to integrate various methods (e.g., finite elements, Rayleigh Ritz, Galerkin, and integral methods) with one another. Since the finite element method will likely be the major method to be integrated, its enhanced robustness under element distortion is also examined and a new robust shell element is demonstrated.

Capillary Array Waveguide Amplified Fluorescence Detector for mHealth

PubMed Central

Balsam, Joshua; Bruck, Hugh Alan; Rasooly, Avraham

2013-01-01

array can potentially be used for sensitive analysis of multiple fluorescent detection assays simultaneously. The simple phone based capillary array approach presented in this paper is capable of amplifying weak fluorescent signals thereby improving the sensitivity of optical detectors based on mobile phones. This may allow sensitive biological assays to be measured with low sensitivity detectors and may make mHealth practical for many diagnostics applications, especially in resource-poor and global health settings. PMID:24039345

Capillary Structures for Exploration Life Support (Capillary Structures)

NASA Image and Video Library

2017-07-10

iss052e013081 (7/10/2017) --- The Capillary Structures for Exploration Life Support (Capillary Structures) investigation studies a new method using structures of specific shapes to manage fluid and gas mixtures. The investigation studies water recycling and carbon dioxide removal, benefiting future efforts to design lightweight, more reliable life support systems for future space missions.

DNA Sequencing Using capillary Electrophoresis

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

Dr. Barry Karger

2011-05-09

The overall goal of this program was to develop capillary electrophoresis as the tool to be used to sequence for the first time the Human Genome. Our program was part of the Human Genome Project. In this work, we were highly successful and the replaceable polymer we developed, linear polyacrylamide, was used by the DOE sequencing lab in California to sequence a significant portion of the human genome using the MegaBase multiple capillary array electrophoresis instrument. In this final report, we summarize our efforts and success. We began our work by separating by capillary electrophoresis double strand oligonucleotides using cross-linkedmore » polyacrylamide gels in fused silica capillaries. This work showed the potential of the methodology. However, preparation of such cross-linked gel capillaries was difficult with poor reproducibility, and even more important, the columns were not very stable. We improved stability by using non-cross linked linear polyacrylamide. Here, the entangled linear chains could move when osmotic pressure (e.g. sample injection) was imposed on the polymer matrix. This relaxation of the polymer dissipated the stress in the column. Our next advance was to use significantly lower concentrations of the linear polyacrylamide that the polymer could be automatically blown out after each run and replaced with fresh linear polymer solution. In this way, a new column was available for each analytical run. Finally, while testing many linear polymers, we selected linear polyacrylamide as the best matrix as it was the most hydrophilic polymer available. Under our DOE program, we demonstrated initially the success of the linear polyacrylamide to separate double strand DNA. We note that the method is used even today to assay purity of double stranded DNA fragments. Our focus, of course, was on the separation of single stranded DNA for sequencing purposes. In one paper, we demonstrated the success of our approach in sequencing up to 500 bases. Other

Automated Parallel Capillary Electrophoretic System

DOEpatents

Li, Qingbo; Kane, Thomas E.; Liu, Changsheng; Sonnenschein, Bernard; Sharer, Michael V.; Kernan, John R.

2000-02-22

An automated electrophoretic system is disclosed. The system employs a capillary cartridge having a plurality of capillary tubes. The cartridge has a first array of capillary ends projecting from one side of a plate. The first array of capillary ends are spaced apart in substantially the same manner as the wells of a microtitre tray of standard size. This allows one to simultaneously perform capillary electrophoresis on samples present in each of the wells of the tray. The system includes a stacked, dual carousel arrangement to eliminate cross-contamination resulting from reuse of the same buffer tray on consecutive executions from electrophoresis. The system also has a gel delivery module containing a gel syringe/a stepper motor or a high pressure chamber with a pump to quickly and uniformly deliver gel through the capillary tubes. The system further includes a multi-wavelength beam generator to generate a laser beam which produces a beam with a wide range of wavelengths. An off-line capillary reconditioner thoroughly cleans a capillary cartridge to enable simultaneous execution of electrophoresis with another capillary cartridge. The streamlined nature of the off-line capillary reconditioner offers the advantage of increased system throughput with a minimal increase in system cost.

Design and operation of a portable scanner for high performance microchip capillary array electrophoresis.

PubMed

Scherer, James R; Liu, Peng; Mathies, Richard A

2010-11-01

We have developed a compact, laser-induced fluorescence detection scanner, the multichannel capillary array electrophoresis portable scanner (McCAEPs) as a platform for electrophoretic detection and control of high-throughput, integrated microfluidic devices for genetic and other analyses. The instrument contains a confocal optical system with a rotary objective for detecting four different fluorescence signals, a pneumatic system consisting of two pressure/vacuum pumps and 28 individual addressable solenoid valves for control of on-chip microvalves and micropumps, four Polymerase Chain Reaction (PCR) temperature control systems, and four high voltage power supplies for electrophoresis. The detection limit of the instrument is ~20 pM for on-chip capillary electrophoresis of fluorescein dyes. To demonstrate the system performance for forensic short tandem repeat (STR) analysis, two experiments were conducted: (i) electrophoretic separation and detection of STR samples on a 96-lane microfabricated capillary array electrophoresis microchip. Fully resolved PowerPlex(®) 16 STR profiles amplified from 1 ng of 9947A female standard DNA were successfully obtained; (ii) nine-plex STR amplification, sample injection, separation, and fluorescence detection of 100-copy 9948 male standard DNA in a single integrated PCR- capillary electrophoresis microchip. These results demonstrate that the McCAEPs can be used as a versatile control and detection instrument that operates integrated microfluidic devices for high-performance forensic human identification.

Design and operation of a portable scanner for high performance microchip capillary array electrophoresis

NASA Astrophysics Data System (ADS)

Scherer, James R.; Liu, Peng; Mathies, Richard A.

2010-11-01

We have developed a compact, laser-induced fluorescence detection scanner, the multichannel capillary array electrophoresis portable scanner (McCAEPs) as a platform for electrophoretic detection and control of high-throughput, integrated microfluidic devices for genetic and other analyses. The instrument contains a confocal optical system with a rotary objective for detecting four different fluorescence signals, a pneumatic system consisting of two pressure/vacuum pumps and 28 individual addressable solenoid valves for control of on-chip microvalves and micropumps, four Polymerase Chain Reaction (PCR) temperature control systems, and four high voltage power supplies for electrophoresis. The detection limit of the instrument is ˜20 pM for on-chip capillary electrophoresis of fluorescein dyes. To demonstrate the system performance for forensic short tandem repeat (STR) analysis, two experiments were conducted: (i) electrophoretic separation and detection of STR samples on a 96-lane microfabricated capillary array electrophoresis microchip. Fully resolved PowerPlex® 16 STR profiles amplified from 1 ng of 9947A female standard DNA were successfully obtained; (ii) nine-plex STR amplification, sample injection, separation, and fluorescence detection of 100-copy 9948 male standard DNA in a single integrated PCR- capillary electrophoresis microchip. These results demonstrate that the McCAEPs can be used as a versatile control and detection instrument that operates integrated microfluidic devices for high-performance forensic human identification.

Local capillary supply in muscle is not determined by local oxidative capacity.

PubMed

Bosutti, Alessandra; Egginton, Stuart; Barnouin, Yoann; Ganse, Bergita; Rittweger, Jörn; Degens, Hans

2015-11-01

It is thought that the prime determinant of global muscle capillary density is the mean oxidative capacity. However, feedback control during maturational growth or adaptive remodelling of local muscle capillarisation is likely to be more complex than simply matching O2 supply and demand in response to integrated tissue function. We tested the hypothesis that the maximal oxygen consumption (MO2,max) supported by a capillary is relatively constant, and independent of the volume of tissue supplied (capillary domain). We demonstrate that local MO2,max assessed by succinate dehydrogenase histochemistry: (1) varied more than 100-fold between individual capillaries and (2) was positively correlated to capillary domain area in both human vastus lateralis (R=0.750, P<0.001) and soleus (R=0.697, P<0.001) muscles. This suggests that, in contrast to common assumptions, capillarisation is not primarily dictated by local oxidative capacity, but rather by factors such as fibre size, or consequences of differences in fibre size such as substrate delivery and metabolite removal. © 2015. Published by The Company of Biologists Ltd.

Multiple-Locus Variable-Number Tandem-Repeats Analysis of Escherichia coli O157 using PCR multiplexing and multi-colored capillary electrophoresis.

PubMed

Lindstedt, Bjørn-Arne; Vardund, Traute; Kapperud, Georg

2004-08-01

The Multiple-Locus Variable-Number Tandem-Repeats Analysis (MLVA) method is currently being used as the primary typing tool for Shiga-toxin-producing Escherichia coli (STEC) O157 isolates in our laboratory. The initial assay was performed using a single fluorescent dye and the different patterns were assigned using a gel image. Here, we present a significantly improved assay using multiple dye colors and enhanced PCR multiplexing to increase speed, and ease the interpretation of the results. The different MLVA patterns are now based on allele sizes entered as character values, thus removing the uncertainties introduced when analyzing band patterns from the gel image. We additionally propose an easy numbering scheme for the identification of separate isolates that will facilitate exchange of typing data. Seventy-two human and animal strains of Shiga-toxin-producing E. coli O157 were used for the development of the improved MLVA assay. The method is based on capillary separation of multiplexed PCR products of VNTR loci in the E. coli O157 genome labeled with multiple fluorescent dyes. The different alleles at each locus were then assigned to allele numbers, which were used for strain comparison.

Smart wheelchair: integration of multiple sensors

NASA Astrophysics Data System (ADS)

Gassara, H. E.; Almuhamed, S.; Moukadem, A.; Schacher, L.; Dieterlen, A.; Adolphe, D.

2017-10-01

The aim of the present work is to develop a smart wheelchair by integrating multiple sensors for measuring user’s physiological signals and subsequently transmitting and monitoring the treated signals to the user, a designated person or institution. Among other sensors, force, accelerometer, and temperature sensors are successfully integrated within both the backrest and the seat cushions of the wheelchair; while a pulse sensor is integrated within the armrest. The pulse sensor is connected to an amplification circuit board that is, in turn, placed within the armrest. The force and temperature sensors are integrated into a textile cover of the cushions by means of embroidery and sewing techniques. The signal from accelerometer is transmitted through Wi-Fi connection. The electrical connections needed for power supplying of sensors are made by embroidered conductive threads.

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

NASA Astrophysics Data System (ADS)

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

1996-07-01

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

An Experimental Study of Pressure Oscillation in a Capillary Pumped Loop with Multiple Evaporators and Condensers

NASA Technical Reports Server (NTRS)

Ku, Jen-Tung; Hoang, Triem T.

1998-01-01

The heat transport capability of a capillary pumped loop (CPL) is limited by the pressure drop that its evaporator wick can sustain. The pressure drop in a CPL is not constant even under seemingly steady operation, but rather exhibits an oscillatory behavior. A hydrodynamic theory based on a mass-spring-dashpot model was previously developed to predict the pressure oscillation in a CPL with a single evaporator and a single condenser. The theory states that the pressure oscillation is a function of physical dimensions of the CPL components and operating conditions. Experimental data agreed very well with theoretical predictions. The hydrodynamic stability theory has recently been extended to predict the pressure oscillations in CPLs with multiple evaporators and multiple condensers. Concurrently, an experimental study was conducted to verify the theory and to investigate the effects of various parameters on the pressure oscillation. Four evaporators with different wick properties were tested using a test loop containing two condenser plates. The test loop allowed the four evaporators to be tested in a single-pump, two-pump or four-pump configuration, and the two condenser plates to be plumbed either in parallel or in series. Test conditions included varying the power input, the reservoir set point temperature, the condenser sink temperature, and the flow resistance between the reservoir and the loop. Experimental results agreed well with theoretical predictions.

Rational design of capillary-driven flows for paper-based microfluidics.

PubMed

Elizalde, Emanuel; Urteaga, Raúl; Berli, Claudio L A

2015-05-21

The design of paper-based assays that integrate passive pumping requires a precise programming of the fluid transport, which has to be encoded in the geometrical shape of the substrate. This requirement becomes critical in multiple-step processes, where fluid handling must be accurate and reproducible for each operation. The present work theoretically investigates the capillary imbibition in paper-like substrates to better understand fluid transport in terms of the macroscopic geometry of the flow domain. A fluid dynamic model was derived for homogeneous porous substrates with arbitrary cross-sectional shapes, which allows one to determine the cross-sectional profile required for a prescribed fluid velocity or mass transport rate. An extension of the model to slit microchannels is also demonstrated. Calculations were validated by experiments with prototypes fabricated in our lab. The proposed method constitutes a valuable tool for the rational design of paper-based assays.

Thermal Integration of a Liquid Acquisition Device into a Cryogenic Feed System

NASA Technical Reports Server (NTRS)

Hastings, L. J.; Bolshinskiy, L. G.; Schunk, R. G.; Martin, A. K.; Eskridge, R. H.; Frenkel, A.; Grayson, G.; Pendleton, M. L.

2011-01-01

Primary objectives of this effort were to define the following: (1) Approaches for quantification of the accumulation of thermal energy within a capillary screen liquid acquisition device (LAD) for a lunar lander upper stage during periods of up to 210 days on the lunar surface, (2) techniques for mitigating heat entrapment, and (3) perform initial testing, data evaluation. The technical effort was divided into the following categories: (1) Detailed thermal modeling of the LAD/feed system interactions using both COMSOL computational fluid device and standard codes, (2) FLOW-3D modeling of bulk liquid to provide interfacing conditions for the LAD thermal modeling, (3) condensation conditioning of capillary screens to stabilize surface tension retention capability, and (4) subscale testing of an integrated LAD/feed system. Substantial progress was achieved in the following technical areas: (1) Thermal modeling and experimental approaches for evaluating integrated cryogen LAD/feed systems, at both the system and component levels, (2) reduced gravity pressure control analyses, (3) analytical modeling and testing for capillary screen conditioning using condensation and wicking, and (4) development of rapid turnaround testing techniques for evaluating LAD/feed system thermal and fluid integration. A comprehensive effort, participants included a diverse cross section of representatives from academia, contractors, and multiple Marshall Space Flight Center organizations.

Capillary discharge source

DOEpatents

Bender, III, Howard Albert

2003-11-25

Debris generation from an EUV electric discharge plasma source device can be significantly reduced or essentially eliminated by encasing the electrodes with dielectric or electrically insulating material so that the electrodes are shielded from the plasma, and additionally by providing a path for the radiation to exit wherein the electrodes are not exposed to the area where the radiation is collected. The device includes: (a) a body, which is made of an electrically insulating material, that defines a capillary bore that has a proximal end and a distal end and that defines at least one radiation exit; (b) a first electrode that defines a first channel that has a first inlet end that is connected to a source of gas and a first outlet end that is in communication with the capillary bore, wherein the first electrode is positioned at the distal end of the capillary bore; (c) a second electrode that defines a second channel that has a second inlet end that is in communication with the capillary bore and an outlet end, wherein the second electrode is positioned at the proximal end of the capillary bore; and (d) a source of electric potential that is connected across the first and second electrodes, wherein radiation generated within the capillary bore is emitted through the at least one radiation exit and wherein the first electrode and second electrode are shielded from the emitted radiation.

Exotic containers for capillary surfaces

NASA Technical Reports Server (NTRS)

Concus, Paul; Finn, Robert

1991-01-01

This paper discusses 'exotic' rotationally symmetric containers that admit an entire continuum of distinct equilibrium capillary free surfaces. The paper extends earlier work to a larger class of parameters and clarifies and simplifies the governing differential equations, while expressing them in a parametric form appropriate for numerical integration. A unified presentation suitable for both zero and nonzero gravity is given. Solutions for the container shapes are depicted graphically along with members of the free-surface continuum, and comments are given concerning possible physical experiments.

A novel instrument for studying the flow behaviour of erythrocytes through microchannels simulating human blood capillaries.

PubMed

Sutton, N; Tracey, M C; Johnston, I D; Greenaway, R S; Rampling, M W

1997-05-01

A novel instrument has been developed to study the microrheology of erythrocytes as they flow through channels of dimensions similar to human blood capillaries. The channels are produced in silicon substrates using microengineering technology. Accurately defined, physiological driving pressures and temperatures are employed whilst precise, real-time image processing allows individual cells to be monitored continuously during their transit. The instrument characterises each cell in a sample of ca. 1000 in terms of its volume and flow velocity profile during its transit through a channel. The unique representation of the data in volume/velocity space provides new insight into the microrheological behaviour of blood. The image processing and subsequent data analysis enable the system to reject anomalous events such as multiple cell transits, thereby ensuring integrity of the resulting data. By employing an array of microfluidic flow channels we can integrate a number of different but precise and highly reproducible channel sizes and geometries within one array, thereby allowing multiple, concurrent isobaric measurements on one sample. As an illustration of the performance of the system, volume/velocity data sets recorded in a microfluidic device incorporating multiple channels of 100 microns length and individual widths ranging between 3.0 and 4.0 microns are presented.

Miniaturized high throughput detection system for capillary array electrophoresis on chip with integrated light emitting diode array as addressed ring-shaped light source.

PubMed

Ren, Kangning; Liang, Qionglin; Mu, Xuan; Luo, Guoan; Wang, Yiming

2009-03-07

A novel miniaturized, portable fluorescence detection system for capillary array electrophoresis (CAE) on a microfluidic chip was developed, consisting of a scanning light-emitting diode (LED) light source and a single point photoelectric sensor. Without charge coupled detector (CCD), lens, fibers and moving parts, the system was extremely simplified. Pulsed driving of the LED significantly increased the sensitivity, and greatly reduced the power consumption and photobleaching effect. The highly integrated system was robust and easy to use. All the advantages realized the concept of a portable micro-total analysis system (micro-TAS), which could work on a single universal serial bus (USB) port. Compared with traditional CAE detecting systems, the current system could scan the radial capillary array with high scanning rate. An 8-channel CAE of fluorescein isothiocyanate (FITC) labeled arginine (Arg) on chip was demonstrated with this system, resulting in a limit of detection (LOD) of 640 amol.

Direct Numerical Simulation of Low Capillary Number Pore Scale Flows

NASA Astrophysics Data System (ADS)

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

2017-12-01

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

Capillary electrophoresis electrospray ionization mass spectrometry interface

DOEpatents

Smith, Richard D.; Severs, Joanne C.

1999-01-01

The present invention is an interface between a capillary electrophoresis separation capillary end and an electrospray ionization mass spectrometry emitter capillary end, for transporting an anolyte sample from a capillary electrophoresis separation capillary to a electrospray ionization mass spectrometry emitter capillary. The interface of the present invention has: (a) a charge transfer fitting enclosing both of the capillary electrophoresis capillary end and the electrospray ionization mass spectrometry emitter capillary end; (b) a reservoir containing an electrolyte surrounding the charge transfer fitting; and (c) an electrode immersed into the electrolyte, the electrode closing a capillary electrophoresis circuit and providing charge transfer across the charge transfer fitting while avoiding substantial bulk fluid transfer across the charge transfer fitting. Advantages of the present invention have been demonstrated as effective in providing high sensitivity and efficient analyses.

Cooperative suction by vertical capillary array pump for controlling flow profiles of microfluidic sensor chips.

PubMed

Horiuchi, Tsutomu; Hayashi, Katsuyoshi; Seyama, Michiko; Inoue, Suzuyo; Tamechika, Emi

2012-10-18

A passive pump consisting of integrated vertical capillaries has been developed for a microfluidic chip as an useful component with an excellent flow volume and flow rate. A fluidic chip built into a passive pump was used by connecting the bottoms of all the capillaries to a top surface consisting of a thin layer channel in the microfluidic chip where the thin layer channel depth was smaller than the capillary radius. As a result the vertical capillaries drew fluid cooperatively rather than independently, thus exerting the maximum suction efficiency at every instance. This meant that a flow rate was realized that exhibited little variation and without any external power or operation. A microfluidic chip built into this passive pump had the ability to achieve a quasi-steady rather than a rapidly decreasing flow rate, which is a universal flow characteristic in an ordinary capillary.

Capillary electrochromatography of inorganic cations in open tubular columns with a controllable capacity multilayered stationary phase architecture.

PubMed

Kubán, Pavel; Kubán, Petr; Kubán, Vlastimil; Hauser, Peter C; Bocek, Petr

2008-05-09

In this paper capillary electrochromatography of alkali and alkaline-earth metal cations in open tubular capillary columns is described. Capillary columns are prepared by coating fused silica capillaries of 75 microm I.D. with poly(butadiene-maleic acid) copolymer (PBMA) in multiple layers. Thermally initiated radical polymerization is used to crosslink the stationary phase. Capillary columns with different number of stationary phase layers can be prepared and allow for the adjustment of separation selectivity in the electrochromatographic mode. Fast and sensitive separations of common inorganic cations are achieved in less than 6 min in a 60 cm capillary column with on-column capacitively coupled contactless conductivity detector. Limits of detection (S/N=3) for the determination of alkali and alkaline-earth metal cations range from 0.3 to 2.5 microM and repeatability is better than 0.5, 4.5 and 6.1% for migration times, peak heights and peak areas, respectively.

Dynamics and Stability of Capillary Surfaces: Liquid Switches at Small Scales

NASA Technical Reports Server (NTRS)

Steen, Paul H.; Bhandar, Anand; Vogel, Michael J.; Hirsa, Amir H.

2004-01-01

The dynamics and stability of systems of interfaces is central to a range of technologies related to the Human Exploration and Development of Space (HEDS). Our premise is that dramatic shape changes can be manipulated to advantage with minimal input, if the system is near instability. The primary objective is to develop the science base to allow novel approaches to liquid management in low-gravity based on this premise. HEDS requires efficient, reliable and lightweight technologies. Our poster will highlight our progress toward this goal using the capillary switch as an example. A capillary surface is a liquid/liquid or liquid/gas interface whose shape is determined by surface tension. For typical liquids (e.g., water) against gas on earth, capillary surfaces occur on the millimeterscale and smaller where shape deformation due to gravity is unimportant. In low gravity, they can occur on the centimeter scale. Capillary surfaces can be combined to make a switch a system with multiple stable states. A capillary switch can generate motion or effect force. To be practical, the energy barriers of such a switch must be tunable, its switching time (kinetics) short and its triggering mechanism reliable. We illustrate these features with a capillary switch that consists of two droplets, coupled by common pressure. As long as contact lines remained pinned, motions are inviscid, even at sub-millimeter scales, with consequent promise of low-power consumption at the device level. Predictions of theory are compared to experiment on i) a soap-film prototype at centimeter scale and ii) a liquid droplet switch at millimeter-scale.

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

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

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

1996-09-15

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 diagnosticmore » 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.« less

Symmetric and asymmetric capillary bridges between a rough surface and a parallel surface.

PubMed

Wang, Yongxin; Michielsen, Stephen; Lee, Hoon Joo

2013-09-03

Although the formation of a capillary bridge between two parallel surfaces has been extensively studied, the majority of research has described only symmetric capillary bridges between two smooth surfaces. In this work, an instrument was built to form a capillary bridge by squeezing a liquid drop on one surface with another surface. An analytical solution that describes the shape of symmetric capillary bridges joining two smooth surfaces has been extended to bridges that are asymmetric about the midplane and to rough surfaces. The solution, given by elliptical integrals of the first and second kind, is consistent with a constant Laplace pressure over the entire surface and has been verified for water, Kaydol, and dodecane drops forming symmetric and asymmetric bridges between parallel smooth surfaces. This solution has been applied to asymmetric capillary bridges between a smooth surface and a rough fabric surface as well as symmetric bridges between two rough surfaces. These solutions have been experimentally verified, and good agreement has been found between predicted and experimental profiles for small drops where the effect of gravity is negligible. Finally, a protocol for determining the profile from the volume and height of the capillary bridge has been developed and experimentally verified.

Instability of the capillary bridge

NASA Astrophysics Data System (ADS)

Pare, Gounseti; Hoepffner, Jerome

2014-11-01

Capillary adhesion is a physical mechanism that maintains two bodies in contact by capillarity through a liquid ligament. The capillary bridge is an idealization of this capillary adhesion. In this study we first focus on the classical case of the stability of the capillary bridge. Secondly we study a slightly more complex configuration, imagining a flow in the capillary bridge as in the case of the dynamics of the neck of a liquid ligament, in its withdrawal under the effect of capillarity. Inspired by the experiments on soap films of Plateau, the configuration analyzed consists of an initially axisymmetric, mass of fluid held by surface tension forces between two parallel, coaxial, solid pipes of the same diameter. The results presented are obtained by numerical simulations using the free software, Gerris Flow Solver. We first focus on the capillary Venturi. In the static configuration the stability diagram of the capillary bridge obtained is in perfect agreement with the results of Lev A. Slobozhanin. In the dynamic case we develop a matlab code based on the one dimensional equations of Eggers and Dupont. The comparison of the bifurcation diagram obtained and the numerical simulations shows a good agreement.

Unsupervised multiple kernel learning for heterogeneous data integration.

PubMed

Mariette, Jérôme; Villa-Vialaneix, Nathalie

2018-03-15

Recent high-throughput sequencing advances have expanded the breadth of available omics datasets and the integrated analysis of multiple datasets obtained on the same samples has allowed to gain important insights in a wide range of applications. However, the integration of various sources of information remains a challenge for systems biology since produced datasets are often of heterogeneous types, with the need of developing generic methods to take their different specificities into account. We propose a multiple kernel framework that allows to integrate multiple datasets of various types into a single exploratory analysis. Several solutions are provided to learn either a consensus meta-kernel or a meta-kernel that preserves the original topology of the datasets. We applied our framework to analyse two public multi-omics datasets. First, the multiple metagenomic datasets, collected during the TARA Oceans expedition, was explored to demonstrate that our method is able to retrieve previous findings in a single kernel PCA as well as to provide a new image of the sample structures when a larger number of datasets are included in the analysis. To perform this analysis, a generic procedure is also proposed to improve the interpretability of the kernel PCA in regards with the original data. Second, the multi-omics breast cancer datasets, provided by The Cancer Genome Atlas, is analysed using a kernel Self-Organizing Maps with both single and multi-omics strategies. The comparison of these two approaches demonstrates the benefit of our integration method to improve the representation of the studied biological system. Proposed methods are available in the R package mixKernel, released on CRAN. It is fully compatible with the mixOmics package and a tutorial describing the approach can be found on mixOmics web site http://mixomics.org/mixkernel/. jerome.mariette@inra.fr or nathalie.villa-vialaneix@inra.fr. Supplementary data are available at Bioinformatics online.

Automatic and integrated micro-enzyme assay (AIμEA) platform for highly sensitive thrombin analysis via an engineered fluorescence protein-functionalized monolithic capillary column.

PubMed

Lin, Lihua; Liu, Shengquan; Nie, Zhou; Chen, Yingzhuang; Lei, Chunyang; Wang, Zhen; Yin, Chao; Hu, Huiping; Huang, Yan; Yao, Shouzhuo

2015-04-21

Nowadays, large-scale screening for enzyme discovery, engineering, and drug discovery processes require simple, fast, and sensitive enzyme activity assay platforms with high integration and potential for high-throughput detection. Herein, a novel automatic and integrated micro-enzyme assay (AIμEA) platform was proposed based on a unique microreaction system fabricated by a engineered green fluorescence protein (GFP)-functionalized monolithic capillary column, with thrombin as an example. The recombinant GFP probe was rationally engineered to possess a His-tag and a substrate sequence of thrombin, which enable it to be immobilized on the monolith via metal affinity binding, and to be released after thrombin digestion. Combined with capillary electrophoresis-laser-induced fluorescence (CE-LIF), all the procedures, including thrombin injection, online enzymatic digestion in the microreaction system, and label-free detection of the released GFP, were integrated in a single electrophoretic process. By taking advantage of the ultrahigh loading capacity of the AIμEA platform and the CE automatic programming setup, one microreaction column was sufficient for many times digestion without replacement. The novel microreaction system showed significantly enhanced catalytic efficiency, about 30 fold higher than that of the equivalent bulk reaction. Accordingly, the AIμEA platform was highly sensitive with a limit of detection down to 1 pM of thrombin. Moreover, the AIμEA platform was robust and reliable to detect thrombin in human serum samples and its inhibition by hirudin. Hence, this AIμEA platform exhibits great potential for high-throughput analysis in future biological application, disease diagnostics, and drug screening.

Information Integration in Multiple Cue Judgment: A Division of Labor Hypothesis

ERIC Educational Resources Information Center

Juslin, Peter; Karlsson, Linnea; Olsson, Henrik

2008-01-01

There is considerable evidence that judgment is constrained to additive integration of information. The authors propose an explanation of why serial and additive cognitive integration can produce accurate multiple cue judgment both in additive and non-additive environments in terms of an adaptive division of labor between multiple representations.…

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

PubMed

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.

Engineering of a complex bone tissue model with endothelialised channels and capillary-like networks.

PubMed

Klotz, B J; Lim, K S; Chang, Y X; Soliman, B G; Pennings, I; Melchels, F P W; Woodfield, T B F; Rosenberg, A J; Malda, J; Gawlitta, D

2018-05-30

In engineering of tissue analogues, upscaling to clinically-relevant sized constructs remains a significant challenge. The successful integration of a vascular network throughout the engineered tissue is anticipated to overcome the lack of nutrient and oxygen supply to residing cells. This work aimed at developing a multiscale bone-tissue-specific vascularisation strategy. Engineering pre-vascularised bone leads to biological and fabrication dilemmas. To fabricate channels endowed with an endothelium and suitable for osteogenesis, rather stiff materials are preferable, while capillarisation requires soft matrices. To overcome this challenge, gelatine-methacryloyl hydrogels were tailored by changing the degree of functionalisation to allow for cell spreading within the hydrogel, while still enabling endothelialisation on the hydrogel surface. An additional challenge was the combination of the multiple required cell-types within one biomaterial, sharing the same culture medium. Consequently, a new medium composition was investigated that simultaneously allowed for endothelialisation, capillarisation and osteogenesis. Integrated multipotent mesenchymal stromal cells, which give rise to pericyte-like and osteogenic cells, and endothelial-colony-forming cells (ECFCs) which form capillaries and endothelium, were used. Based on the aforementioned optimisation, a construct of 8 × 8 × 3 mm, with a central channel of 600 µm in diameter, was engineered. In this construct, ECFCs covered the channel with endothelium and osteogenic cells resided in the hydrogel, adjacent to self-assembled capillary-like networks. This study showed the promise of engineering complex tissue constructs by means of human primary cells, paving the way for scaling-up and finally overcoming the challenge of engineering vascularised tissues.

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

PubMed Central

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

2015-01-01

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

Composition of the C6+ Fraction of Natural Gas by Multiple Porous Layer Open Tubular Capillaries Maintained at Low Temperatures*

PubMed Central

Burger, Jessica L.; Lovestead, Tara M.; Bruno, Thomas J.

2017-01-01

As the sources of natural gas become more diverse, the trace constituents of the C6+ fraction are of increasing interest. Analysis of fuel gas (including natural gas) for compounds with more than 6 carbon atoms (the C6+ fraction) has historically been complex and expensive. Hence, this is a procedure that is used most often in troubleshooting rather than for day-to-day operations. The C6+ fraction affects gas quality issues and safety considerations such as anomalies associated with odorization. Recent advances in dynamic headspace vapor collection can be applied to this analysis and provide a faster, less complex alternative for compositional determination of the C6+ fraction of natural gas. Porous layer open tubular capillaries maintained at low temperatures (PLOT-cryo) form the basis of a dynamic headspace sampling method that was developed at NIST initially for explosives in 2009. This method has been recently advanced by the combining of multiple PLOT capillary traps into one “bundle,” or wafer, resulting in a device that allows the rapid trapping of relatively large amounts of analyte. In this study, natural gas analytes were collected by flowing natural gas from the laboratory (gas out of the wall) or a prepared surrogate gas flowing through a chilled wafer. The analytes were then removed from the PLOT-cryo wafer by thermal desorption and subsequent flushing of the wafer with helium. Gas chromatography (GC) with mass spectrometry (MS) was then used to identify the analytes. PMID:29332993

Composition of the C6+ Fraction of Natural Gas by Multiple Porous Layer Open Tubular Capillaries Maintained at Low Temperatures.

PubMed

Burger, Jessica L; Lovestead, Tara M; Bruno, Thomas J

2016-03-17

As the sources of natural gas become more diverse, the trace constituents of the C 6 + fraction are of increasing interest. Analysis of fuel gas (including natural gas) for compounds with more than 6 carbon atoms (the C 6 + fraction) has historically been complex and expensive. Hence, this is a procedure that is used most often in troubleshooting rather than for day-to-day operations. The C 6 + fraction affects gas quality issues and safety considerations such as anomalies associated with odorization. Recent advances in dynamic headspace vapor collection can be applied to this analysis and provide a faster, less complex alternative for compositional determination of the C 6 + fraction of natural gas. Porous layer open tubular capillaries maintained at low temperatures (PLOT-cryo) form the basis of a dynamic headspace sampling method that was developed at NIST initially for explosives in 2009. This method has been recently advanced by the combining of multiple PLOT capillary traps into one "bundle," or wafer, resulting in a device that allows the rapid trapping of relatively large amounts of analyte. In this study, natural gas analytes were collected by flowing natural gas from the laboratory (gas out of the wall) or a prepared surrogate gas flowing through a chilled wafer. The analytes were then removed from the PLOT-cryo wafer by thermal desorption and subsequent flushing of the wafer with helium. Gas chromatography (GC) with mass spectrometry (MS) was then used to identify the analytes.

Multiplexed capillary electrophoresis system

DOEpatents

Yeung, Edward S.; Li, Qingbo; Lu, Xiandan

1998-04-21

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.

Multiplexed capillary electrophoresis system

DOEpatents

Yeung, Edward S.; Chang, Huan-Tsang; Fung, Eliza N.; Li, Qingbo; Lu, Xiandan

1996-12-10

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.

Multiplexed capillary electrophoresis system

DOEpatents

Yeung, E.S.; Li, Q.; Lu, X.

1998-04-21

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.

Multiplexed capillary electrophoresis system

DOEpatents

Yeung, E.S.; Chang, H.T.; Fung, E.N.; Li, Q.; Lu, X.

1996-12-10

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.

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

PubMed

Duan, Lian; Cao, Zhen; Yobas, Levent

2017-09-19

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

A hybrid fluorous monolithic capillary column with integrated nanoelectrospray ionization emitter for determination of perfluoroalkyl acids by nano-liquid chromatography-nanoelectrospray ionization-mass spectrometry/mass spectrometry.

PubMed

Zhang, Haiyang; Ou, Junjie; Wei, Yinmao; Wang, Hongwei; Liu, Zhongshan; Zou, Hanfa

2016-04-01

A hybrid fluorous monolithic column was simply prepared via photo-initiated free radical polymerization of an acrylopropyl polyhedral oligomeric silsesquioxane (acryl-POSS) and a perfluorous monomer (2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoroheptyl acrylate) in UV-transparent fused-silica capillaries within 5min. The physical characterization of hybrid fluorous monolith, including scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy, mercury intrusion porosimetry (MIP) and nitrogen adsorption/desorption measurement was performed. Chromatographic performance was also evaluated by capillary liquid chromatography (cLC). Due to the fluorous-fluorous interaction between fluorous monolith and analytes, fluorobenzenes could well be separated, and the column efficiencies reached 86,600-92,500plates/m at the velocity of 0.87mm/s for alkylbenzenes and 51,900-76,000plates/m at the velocity of 1.10mm/s for fluorobenzenes. Meanwhile, an approach to integrate nanoelectrospray ionization (ESI) emitter with hybrid fluorous monolithic column was developed for quantitative determination of perfluoroalkyl acids by nanoHPLC-ESI-MS/MS. The integration design could minimize extracolumn volume, thus excluding undesirable peak broadening and improving separation performance. Copyright © 2016 Elsevier B.V. All rights reserved.

Capillary pumped loop body heat exchanger

NASA Technical Reports Server (NTRS)

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.

Integrable generalizations of non-linear multiple three-wave interaction models

NASA Astrophysics Data System (ADS)

Jurčo, Branislav

1989-07-01

Integrable generalizations of multiple three-wave interaction models in terms of r-matrix formulation are investigated. The Lax representations, complete sets of first integrals in involution are constructed, the quantization leading to Gaudin's models is discussed.

Measurement of the refractive index of microquantity liquid filled in a capillary and a capillary wall without destruction.

PubMed

Li, Qiang; Pu, Xiaoyun

2013-07-20

A method for measuring the refractive index (RI) of a small volume of liquid and a capillary wall is presented in this paper. A transparent capillary filled with liquid is used as a cylindrical positive lens; subsequently, the focal length of the lens is derived through the base of paraxial approximation, which is recorded as a function of the RIs of the liquid and capillary wall. With the RI of a capillary wall known, the RI of the liquid can be obtained by measuring the focal length of the lens, which is characterized by a microquantity liquid, spatial resolution, and easy operation. The RI of the capillary wall can be calculated without ruining the capillary if the capillary is filled with a standard liquid (RI is known), the deviation of which is less than 0.003 RIU. The factors affecting accuracy of the measurement, for instance, the depth of a field (DOF) in a reading microscope system and the outer and inner diameters of a capillary are analyzed, while illustrating that the effective DOF plays an essential role in accurate measurement.

Fluid Delivery System For Capillary Electrophoretic Applications.

DOEpatents

Li, Qingbo; Liu, Changsheng; Kane, Thomas E.; Kernan, John R.; Sonnenschein, Bernard; Sharer, Michael V.

2002-04-23

An automated electrophoretic system is disclosed. The system employs a capillary cartridge having a plurality of capillary tubes. The cartridge has a first array of capillary ends projecting from one side of a plate. The first array of capillary ends are spaced apart in substantially the same manner as the wells of a microtitre tray of standard size. This allows one to simultaneously perform capillary electrophoresis on samples present in each of the wells of the tray. The system includes a stacked, dual carrousel arrangement to eliminate cross-contamination resulting from reuse of the same buffer tray on consecutive executions from electrophoresis. The system also has a gel delivery module containing a gel syringe/a stepper motor or a high pressure chamber with a pump to quickly and uniformly deliver gel through the capillary tubes. The system further includes a multi-wavelength beam generator to generate a laser beam which produces a beam with a wide range of wavelengths. An off-line capillary reconditioner thoroughly cleans a capillary cartridge to enable simultaneous execution of electrophoresis with another capillary cartridge. The streamlined nature of the off-line capillary reconditioner offers the advantage of increased system throughput with a minimal increase in system cost.

Western blotting using capillary electrophoresis.

PubMed

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.

Capillary optics for radiation focusing

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

Peurrung, A.J.; Reeder, P.L.; Bliss, M.

Capillary lens technology may ultimately bring benefits to neutron and x-ray-based science like conventional lenses with visible light. Although the technology is not yet 10 years old, these lenses have already had a significant impact in engineering, science, and medicine. Capillary lenses are advantageous when it is desirable to increase the radiation flux at a location without regard to its angular divergence. PNNL has worked to improve the technology in several ways. A single, optimally tapered capillary was manufactured, which allows intensity gains of a factor of 270 for an initially parallel, incident x-ray beam. Feasibility of constructing neutron lensesmore » using {sup 58}Ni (particularly effective at reflecting neutrons) has been explored. Three applications for capillary optics have been identified and studied: neutron telescope, Gandolphi x-ray diffractometry, and neutron radiotherapy. A brief guide is given for determining which potential applications are likely to be helped by capillary optics.« less

Progression of Diabetic Capillary Occlusion: A Model

PubMed Central

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

2016-01-01

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

Effect of ultrasonic capillary dynamics on the mechanics of thermosonic ball bonding.

PubMed

Huang, Yan; Shah, Aashish; Mayer, Michael; Zhou, Norman Y; Persic, John

2010-01-01

Microelectronic wire bonding is an essential step in today's microchip production. It is used to weld (bond) microwires to metallized pads of integrated circuits using ultrasound with hundreds of thousands of vibration cycles. Thermosonic ball bonding is the most popular variant of the wire bonding process and frequently investigated using finite element (FE) models that simplify the ultrasonic dynamics of the process with static or quasistatic boundary conditions. In this study, the ultrasonic dynamics of the bonding tool (capillary), made from Al(2)O(3), is included in a FE model. For more accuracy of the FE model, the main material parameters are measured. The density of the capillary was measured to be rho(cap) = 3552 +/- 100 kg/m(3). The elastic modulus of the capillary, E(cap) = 389 +/- 11 GPa, is found by comparing an auxiliary FE model of the free vibrating capillary with measured values. A capillary "nodding effect" is identified and found to be essential when describing the ultrasonic vibration shape. A main FE model builds on these results and adds bonded ball, pad, chip, and die attach components. There is excellent agreement between the main model and the ultrasonic force measured at the interface on a test chip with stress microsensors. Bonded ball and underpad stress results are reported. When adjusted to the same ultrasonic force, a simplified model without ultrasonic dynamics and with an infinitely stiff capillary tip is substantially off target by -40% for the maximum underpad stress. The compliance of the capillary causes a substantial inclination effect at the bonding interface between wire and pad. This oscillating inclination effect massively influences the stress fields under the pad and is studied in more detail. For more accurate results, it is therefore recommended to include ultrasonic dynamics of the bonding tool in mechanical FE models of wire bonding.

The in-capillary DPPH-capillary electrophoresis-the diode array detector combined with reversed-electrode polarity stacking mode for screening and quantifying major antioxidants in Cuscuta chinensis Lam.

PubMed

Liu, Jiao; Tian, Ji; Li, Jin; Azietaku, John Teye; Zhang, Bo-Li; Gao, Xiu-Mei; Chang, Yan-Xu

2016-07-01

An in-capillary 2, 2-diphenyl-1-picrylhydrazyl (DPPH)-CE-the DAD (in-capillary DPPH-CE-DAD) combined with reversed-electrode polarity stacking mode has been developed to screen and quantify the active antioxidant components of Cuscuta chinensis Lam. The operation parameters were optimized with regard to the pH and concentration of buffer solution, SDS, β-CDs, organic modifier, as well as separation voltage and temperature. Six antioxidants including chlorogenic acid, p-coumaric acid, rutin, hyperin, isoquercitrin, and astragalin were screened and the total antioxidant activity of the complex matrix was successfully evaluated based on the decreased peak area of DPPH by the established DPPH-CE-DAD method. Sensitivity was enhanced under reversed-electrode polarity stacking mode and 10- to 31-fold of magnitude improvement in detection sensitivity for each analyte was attained. The results demonstrated that the newly established in-capillary DPPH-CE-DAD method combined with reversed-electrode polarity stacking mode could integrate sample concentration, the oxidizing reaction, separation, and detection into one capillary to fully automate the system. It was considered a suitable technique for the separation, screening, and determination of trace antioxidants in natural products. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Gas Flow in the Capillary of the Atmosphere-to-Vacuum Interface of Mass Spectrometers

NASA Astrophysics Data System (ADS)

Skoblin, Michael; Chudinov, Alexey; Soulimenkov, Ilia; Brusov, Vladimir; Kozlovskiy, Viacheslav

2017-10-01

Numerical simulations of a gas flow through a capillary being a part of mass spectrometer atmospheric interface were performed using a detailed laminar flow model. The simulated interface consisted of atmospheric and forevacuum volumes connected via a thin capillary. The pressure in the forevacuum volume where the gas was expanding after passing through the capillary was varied in the wide range from 10 to 900 mbar in order to study the volume flow rate as well as the other flow parameters as functions of the pressure drop between the atmospheric and forevacuum volumes. The capillary wall temperature was varied in the range from 24 to 150 °C. Numerical integration of the complete system of Navier-Stokes equations for a viscous compressible gas taking into account the heat transfer was performed using the standard gas dynamic simulation software package ANSYS CFX. The simulation results were compared with experimental measurements of gas flow parameters both performed using our experimental setup and taken from the literature. The simulated volume flow rates through the capillary differed no more than by 10% from the measured ones over the entire pressure and temperatures ranges. A conclusion was drawn that the detailed digital laminar model is able to quantitatively describe the measured gas flow rates through the capillaries under conditions considered. [Figure not available: see fulltext.

Gas Flow in the Capillary of the Atmosphere-to-Vacuum Interface of Mass Spectrometers.

PubMed

Skoblin, Michael; Chudinov, Alexey; Soulimenkov, Ilia; Brusov, Vladimir; Kozlovskiy, Viacheslav

2017-10-01

Numerical simulations of a gas flow through a capillary being a part of mass spectrometer atmospheric interface were performed using a detailed laminar flow model. The simulated interface consisted of atmospheric and forevacuum volumes connected via a thin capillary. The pressure in the forevacuum volume where the gas was expanding after passing through the capillary was varied in the wide range from 10 to 900 mbar in order to study the volume flow rate as well as the other flow parameters as functions of the pressure drop between the atmospheric and forevacuum volumes. The capillary wall temperature was varied in the range from 24 to 150 °C. Numerical integration of the complete system of Navier-Stokes equations for a viscous compressible gas taking into account the heat transfer was performed using the standard gas dynamic simulation software package ANSYS CFX. The simulation results were compared with experimental measurements of gas flow parameters both performed using our experimental setup and taken from the literature. The simulated volume flow rates through the capillary differed no more than by 10% from the measured ones over the entire pressure and temperatures ranges. A conclusion was drawn that the detailed digital laminar model is able to quantitatively describe the measured gas flow rates through the capillaries under conditions considered. Graphical Abstract ᅟ.

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

PubMed

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.

Capillary-Condenser-Pumped Heat-Transfer Loop

NASA Technical Reports Server (NTRS)

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.

Microcephaly-capillary malformation syndrome: Brothers with a homozygous STAMBP mutation, uncovered by exome sequencing.

PubMed

Naseer, Muhammad Imran; Sogaty, Sameera; Rasool, Mahmood; Chaudhary, Adeel G; Abutalib, Yousif Ahmed; Walker, Susan; Marshall, Christian R; Merico, Daniele; Carter, Melissa T; Scherer, Stephen W; Al-Qahtani, Mohammad H; Zarrei, Mehdi

2016-11-01

We describe two brothers from a consanguineous family of Egyptian ancestry, presenting with microcephaly, apparent global developmental delay, seizures, spasticity, congenital blindness, and multiple cutaneous capillary malformations. Through exome sequencing, we uncovered a homozygous missense variant in STAMBP (p.K303R) in the two siblings, inherited from heterozygous carrier parents. Mutations in STAMBP are known to cause microcephaly-capillary malformation syndrome (MIC-CAP) and the phenotype in this family is consistent with this diagnosis. We compared the findings in the present brothers with those of earlier reported patients. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

A low-cost, manufacturable method for fabricating capillary and optical fiber interconnects for microfluidic devices.

PubMed

Hartmann, Daniel M; Nevill, J Tanner; Pettigrew, Kenneth I; Votaw, Gregory; Kung, Pang-Jen; Crenshaw, Hugh C

2008-04-01

Microfluidic chips require connections to larger macroscopic components, such as light sources, light detectors, and reagent reservoirs. In this article, we present novel methods for integrating capillaries, optical fibers, and wires with the channels of microfluidic chips. The method consists of forming planar interconnect channels in microfluidic chips and inserting capillaries, optical fibers, or wires into these channels. UV light is manually directed onto the ends of the interconnects using a microscope. UV-curable glue is then allowed to wick to the end of the capillaries, fibers, or wires, where it is cured to form rigid, liquid-tight connections. In a variant of this technique, used with light-guiding capillaries and optical fibers, the UV light is directed into the capillaries or fibers, and the UV-glue is cured by the cone of light emerging from the end of each capillary or fiber. This technique is fully self-aligned, greatly improves both the quality and the manufacturability of the interconnects, and has the potential to enable the fabrication of interconnects in a fully automated fashion. Using these methods, including a semi-automated implementation of the second technique, over 10,000 interconnects have been formed in almost 2000 microfluidic chips made of a variety of rigid materials. The resulting interconnects withstand pressures up to at least 800psi, have unswept volumes estimated to be less than 10 femtoliters, and have dead volumes defined only by the length of the capillary.

Development of a cryogenic capillary pumped loop

NASA Astrophysics Data System (ADS)

Kroliczek, Edward J.; Cullimore, Brent

1996-03-01

This paper describes the initial development of a promising new cryogenic technology. Room temperature capillary pumped loops (CPLs), a derivative of heat pipe technology, have been under development for almost two decades and are emerging as a design solution for many spacecraft thermal control problems. While cryogenic capillary pumped loops have application to passive spacecraft radiators and to long term storage of cryogenic propellants and open-cycle coolants, their application to the integration of spacecraft cryocoolers has generated the most excitement. Without moving parts or complex controls, they are able to thermally connect redundant cryocoolers to a single remote load, eliminating thermal switches and providing mechanical isolation at the same time. Development of a cryogenic CPL (CCPL) presented some unique challenges including start-up from a super-critical state, the management of parasitic heat leaks and pressure containment at ambient temperatures. These challenges have been overcome with a novel design that requires no additional devices or preconditioning for start-up. This paper describes the design concept and development and results conducted under SBIR Phase I and Phase II.

Detection system of capillary array electrophoresis microchip based on optical fiber

NASA Astrophysics Data System (ADS)

Yang, Xiaobo; Bai, Haiming; Yan, Weiping

2009-11-01

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

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

NASA Astrophysics Data System (ADS)

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

2017-11-01

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

Validating Measurement of Knowledge Integration in Science Using Multiple-Choice and Explanation Items

ERIC Educational Resources Information Center

Lee, Hee-Sun; Liu, Ou Lydia; Linn, Marcia C.

2011-01-01

This study explores measurement of a construct called knowledge integration in science using multiple-choice and explanation items. We use construct and instructional validity evidence to examine the role multiple-choice and explanation items plays in measuring students' knowledge integration ability. For construct validity, we analyze item…

Integral Methodological Pluralism in Science Education Research: Valuing Multiple Perspectives

ERIC Educational Resources Information Center

Davis, Nancy T.; Callihan, Laurie P.

2013-01-01

This article examines the multiple methodologies used in educational research and proposes a model that includes all of them as contributing to understanding educational contexts and research from multiple perspectives. The model, based on integral theory (Wilber in a theory of everything. Shambhala, Boston, 2000) values all forms of research as…

Capillary test specimen, system, and methods for in-situ visualization of capillary flow and fillet formation

DOEpatents

Hall, Aaron C.; Hosking, F. Michael ,; Reece, Mark

2003-06-24

A capillary test specimen, method, and system for visualizing and quantifying capillary flow of liquids under realistic conditions, including polymer underfilling, injection molding, soldering, brazing, and casting. The capillary test specimen simulates complex joint geometries and has an open cross-section to permit easy visual access from the side. A high-speed, high-magnification camera system records the location and shape of the moving liquid front in real-time, in-situ as it flows out of a source cavity, through an open capillary channel between two surfaces having a controlled capillary gap, and into an open fillet cavity, where it subsequently forms a fillet on free surfaces that have been configured to simulate realistic joint geometries. Electric resistance heating rapidly heats the test specimen, without using a furnace. Image-processing software analyzes the recorded images and calculates the velocity of the moving liquid front, fillet contact angles, and shape of the fillet's meniscus, among other parameters.

Curvature capillary migration of microspheres.

PubMed

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

2015-09-14

We address the question: how does capillarity propel microspheres along curvature gradients? For a particle on a fluid interface, there are two conditions that can apply at the three phase contact line: either the contact line adopts an equilibrium contact angle, or it can be pinned by kinetic trapping, e.g. at chemical heterogeneities, asperities, or other pinning sites on the particle surface. We formulate the curvature capillary energy for both scenarios for particles smaller than the capillary length and far from any pinning boundaries. The scale and range of the distortion made by the particle are set by the particle radius; we use singular perturbation methods to find the distortions and to rigorously evaluate the associated capillary energies. For particles with equilibrium contact angles, contrary to the literature, we find that the capillary energy is negligible, with the first contribution bounded to fourth order in the product of the particle radius and the deviatoric curvature of the host interface. For pinned contact lines, we find curvature capillary energies that are finite, with a functional form investigated previously by us for disks and microcylinders on curved interfaces. In experiments, we show microspheres migrate along deterministic trajectories toward regions of maximum deviatoric curvature with curvature capillary energies ranging from 6 × 10(3)-5 × 10(4)kBT. These data agree with the curvature capillary energy for the case of pinned contact lines. The underlying physics of this migration is a coupling of the interface deviatoric curvature with the quadrupolar mode of nanometric disturbances in the interface owing to the particle's contact line undulations. This work is an example of the major implications of nanometric roughness and contact line pinning for colloidal dynamics.

Capillary condenser/evaporator

NASA Technical Reports Server (NTRS)

Valenzuela, Javier A. (Inventor)

2010-01-01

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

Micro-injector for capillary electrophoresis.

PubMed

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.

Design of Capillary Flows with Spatially Graded Porous Films

NASA Astrophysics Data System (ADS)

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

2013-11-01

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

Mutations in STAMBP, encoding a deubiquitinating enzyme, cause Microcephaly-Capillary Malformation syndrome

PubMed Central

McDonell, Laura M.; Mirzaa, Ghayda M.; Alcantara, Diana; Schwartzentruber, Jeremy; Carter, Melissa T.; Lee, Leo J.; Clericuzio, Carol L.; Graham, John M.; Morris-Rosendahl, Deborah J.; Polster, Tilman; Acsadi, Gyula; Townshend, Sharron; Williams, Simon; Halbert, Anne; Isidor, Bertrand; Smyser, Christopher D.; Paciorkowski, Alex R.; Willing, Marcia; Woulfe, John; Das, Soma; Beaulieu, Chandree L.; Marcadier, Janet; Geraghty, Michael T.; Frey, Brendan J.; Majewski, Jacek; Bulman, Dennis E.; Dobyns, William B.; O’Driscoll, Mark; Boycott, Kym M.

2014-01-01

Microcephaly-capillary malformation (MIC-CAP) syndrome exhibits severe microcephaly with progressive cortical atrophy, intractable epilepsy, profound developmental delay and multiple small capillary malformations on the skin. We employed whole-exome sequencing of five patients with MIC-CAP syndrome and identified novel recessive mutations in STAMBP, a gene encoding the deubiquitinating (DUB) isopeptidase STAMBP (STAM-binding protein)/AMSH (Associated Molecule with the SH3 domain of STAM), that plays a key role in cell surface receptor-mediated endocytosis and sorting. Patient cell lines showed reduced STAMBP expression associated with accumulation of ubiquitin-conjugated protein aggregates, elevated apoptosis and insensitive activation of the RAS-MAPK and PI3K-AKT-mTOR pathways. The latter cellular phenotype is significant considering the established connection between these pathways and their association with vascular and capillary malformations. Furthermore, our findings of a congenital human disorder caused by a defective DUB protein that functions in endocytosis, implicates ubiquitin-conjugate aggregation and elevated apoptosis as factors potentially influencing the progressive neuronal loss underlying MIC-CAP. PMID:23542699

Electron transmission through a steel capillary

NASA Astrophysics Data System (ADS)

Maljković, J. B.; Borka, D.; Ranković, M. Lj.; Marinković, B. P.; Milosavljević, A. R.; Lemell, C.; Tőkési, K.

2018-05-01

The transmission of low-energy electrons through a macroscopic steel capillary has been investigated both experimentally and theoretically. The length of the steel capillary was L = 19.5 mm and the inner diameter was d = 0.9 mm. The kinetic energy distribution of electrons transmitted through the steel capillary was recorded for a tilt angle of ψ = 2.6 ° of the incident electron beam with respect to the capillary axis. Accompanying simulations based on classical transport theory reproduce the experimental data to a high degree of agreement. Transmission for other tilt angles has also been simulated to investigate the influence of the tilt angle on the guiding efficiency.

Transient studies of capillary-induced flow

NASA Technical Reports Server (NTRS)

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

1993-01-01

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

A neuron-in-capillary platform for facile collection and mass spectrometric characterization of a secreted neuropeptide

PubMed Central

Lee, Chang Young; Fan, Yi; Rubakhin, Stanislav S.; Yoon, Sook; Sweedler, Jonathan V.

2016-01-01

The integration of microfluidic devices—which efficiently handle small liquid volumes—with separations/mass spectrometry (MS) is an effective approach for profiling the neurochemistry occurring in selected neurons. Interfacing the microfluidic cell culture to the mass spectrometer is challenging because of geometric and scaling issues. Here we demonstrate the hyphenation of a neuron-in-capillary platform to a solid phase extraction device and off-line MS. A primary neuronal culture of Aplysia californica neurons was established directly inside a cylindrical polyimide capillary. The approach also uses a particle-embedded monolith to condition neuropeptide releasates collected from several Aplysia neurons cultured in the capillary, with the subsequent characterization of released peptides via MS. This system presents a number of advances compared to more traditional microfluidic devices fabricated with polydimethylsiloxane. These include low cost, easy access to cell culture, rigidity, ease of transport, and minimal fluid handling. The cylindrical geometry of the platform allows convenient interface with a wide range of analytical tools that utilize capillary columns. PMID:27245782

Sheathless interface for coupling capillary electrophoresis with mass spectrometry

DOEpatents

Wang, Chenchen; Tang, Keqi; Smith, Richard D.

2014-06-17

A sheathless interface for coupling capillary electrophoresis (CE) with mass spectrometry is disclosed. The sheathless interface includes a separation capillary for performing CE separation and an emitter capillary for electrospray ionization. A portion of the emitter capillary is porous or, alternatively, is coated to form an electrically conductive surface. A section of the emitter capillary is disposed within the separation capillary, forming a joint. A metal tube, containing a conductive liquid, encloses the joint.

Portable integrated capillary-electrophoresis system using disposable polymer chips with capacitively coupled contactless conductivity detection for on-site analysis of foodstuff

NASA Astrophysics Data System (ADS)

Gärtner, Claudia; Hoffmann, Werner; Demattio, Horst; Clemens, Thomas; Klotz, Matthias; Klemm, Richard; Becker, Holger

2009-05-01

We present a compact portable chip-based capillary electrophoresis system that employs capacitively coupled contactless conductivity detection (C4D) operating at 4 MHz as an alternative detection method compared to the commonly used optical detection based on laser-induced fluorescence. Emphasis was put on system integration and industrial manufacturing technologies for the system. Therefore, the disposable chip for this system is fabricated out of PMMA using injection molding; the electrodes are screen-printed or thin-film electrodes. The system is designed for the measurement of small ionic species like Li+, Na+, K+, SO42- or NO3- typically present in foods like milk and mineral water as well as acids e.g. in wine.

Use of Dried Capillary Blood Sampling for Islet Autoantibody Screening in Relatives: A Feasibility Study.

PubMed

Bingley, Polly J; Rafkin, Lisa E; Matheson, Della; Steck, Andrea K; Yu, Liping; Henderson, Courtney; Beam, Craig A; Boulware, David C

2015-12-01

Islet autoantibody testing provides the basis for assessment of risk of progression to type 1 diabetes. We set out to determine the feasibility and acceptability of dried capillary blood spot-based screening to identify islet autoantibody-positive relatives potentially eligible for inclusion in prevention trials. Dried blood spot (DBS) and venous samples were collected from 229 relatives participating in the TrialNet Pathway to Prevention Study. Both samples were tested for glutamic acid decarboxylase, islet antigen 2, and zinc transporter 8 autoantibodies, and venous samples were additionally tested for insulin autoantibodies and islet cell antibodies. We defined multiple autoantibody positive as two or more autoantibodies in venous serum and DBS screen positive if one or more autoantibodies were detected. Participant questionnaires compared the sample collection methods. Of 44 relatives who were multiple autoantibody positive in venous samples, 42 (95.5%) were DBS screen positive, and DBS accurately detected 145 of 147 autoantibody-negative relatives (98.6%). Capillary blood sampling was perceived as more painful than venous blood draw, but 60% of participants would prefer initial screening using home fingerstick with clinic visits only required if autoantibodies were found. Capillary blood sampling could facilitate screening for type 1 diabetes prevention studies.

Use of Dried Capillary Blood Sampling for Islet Autoantibody Screening in Relatives: A Feasibility Study

PubMed Central

Rafkin, Lisa E.; Matheson, Della; Steck, Andrea K.; Yu, Liping; Henderson, Courtney; Beam, Craig A.; Boulware, David C.

2015-01-01

Abstract Background: Islet autoantibody testing provides the basis for assessment of risk of progression to type 1 diabetes. We set out to determine the feasibility and acceptability of dried capillary blood spot–based screening to identify islet autoantibody–positive relatives potentially eligible for inclusion in prevention trials. Materials and Methods: Dried blood spot (DBS) and venous samples were collected from 229 relatives participating in the TrialNet Pathway to Prevention Study. Both samples were tested for glutamic acid decarboxylase, islet antigen 2, and zinc transporter 8 autoantibodies, and venous samples were additionally tested for insulin autoantibodies and islet cell antibodies. We defined multiple autoantibody positive as two or more autoantibodies in venous serum and DBS screen positive if one or more autoantibodies were detected. Participant questionnaires compared the sample collection methods. Results: Of 44 relatives who were multiple autoantibody positive in venous samples, 42 (95.5%) were DBS screen positive, and DBS accurately detected 145 of 147 autoantibody-negative relatives (98.6%). Capillary blood sampling was perceived as more painful than venous blood draw, but 60% of participants would prefer initial screening using home fingerstick with clinic visits only required if autoantibodies were found. Conclusions: Capillary blood sampling could facilitate screening for type 1 diabetes prevention studies. PMID:26375197

The Effects of Tasks on Integrating Information from Multiple Documents

ERIC Educational Resources Information Center

Cerdan, Raquel; Vidal-Abarca, Eduardo

2008-01-01

The authors examine 2 issues: (a) how students integrate information from multiple scientific documents to describe and explain a physical phenomenon that represents a subset of the information in the documents; and (b) the role of 2 sorts of tasks to achieve this type of integration, either writing an essay on a question requiring integration…

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

PubMed

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.

Capillary electrochromatography and capillary electrochromatography-electrospray mass spectrometry for the separation of non-steroidal anti-inflammatory drugs.

PubMed

Desiderio, C; Fanali, S

2000-10-20

In this study capillary electrochromatography (CEC) was utilized for the separation of ten non-steroidal anti-inflammatory drugs (NSAIDs). Experiments were carried out in a commercially available CE instrument using a packed capillary with RP-18 silica particles where the stationary phase completely filled the capillary. The mobile phase consisted of a mixture of ammonium formate buffer pH 2.5 and acetonitrile. Selectivity and resolution were studied changing the pH and the concentration of the buffer, the acetonitrile content mobile phase and the capillary temperature. The optimum experimental conditions for CEC separation of the studied drug mixture were found using 50 mM ammonium formate pH 2.5-acetonitrile (40:60) at 25 degrees C. The CEC capillary was coupled to an electrospray mass spectrometer for the characterization of the NSAIDs. A mobile phase composed by the same buffer but with a higher concentration of acetonitrile (90%) was used in order to speed up the separation of analytes.

Pore-scale modeling of Capillary Penetration of Wetting Liquid into 3D Fibrous Media: A Critical Examination of Equivalent Capillary Concept

NASA Astrophysics Data System (ADS)

Palakurthi, Nikhil Kumar; Ghia, Urmila; Comer, Ken

2013-11-01

Capillary penetration of liquid through fibrous porous media is important in many applications such as printing, drug delivery patches, sanitary wipes, and performance fabrics. Historically, capillary transport (with a distinct liquid propagating front) in porous media is modeled using capillary-bundle theory. However, it is not clear if the capillary model (Washburn equation) describes the fluid transport in porous media accurately, as it assumes uniformity of pore sizes in the porous medium. The present work investigates the limitations of the applicability of the capillary model by studying liquid penetration through virtual fibrous media with uniform and non-uniform pore-sizes. For the non-uniform-pore fibrous medium, the effective capillary radius of the fibrous medium was estimated from the pore-size distribution curve. Liquid penetration into the 3D virtual fibrous medium at micro-scale was simulated using OpenFOAM, and the numerical results were compared with the Washburn-equation capillary-model predictions. Preliminary results show that the Washburn equation over-predicts the height rise in the early stages (purely inertial and visco-inertial stages) of capillary transport.

Pericytes as Inducers of Rapid, Matrix Metalloproteinase-9-Dependent Capillary Damage during Ischemia

PubMed Central

Underly, Robert G.; Levy, Manuel; Hartmann, David A.; Grant, Roger I.; Watson, Ashley N.

2017-01-01

Blood–brain barrier disruption (BBB) and release of toxic blood molecules into the brain contributes to neuronal injury during stroke and other cerebrovascular diseases. While pericytes are builders and custodians of the BBB in the normal brain, their impact on BBB integrity during ischemia remains unclear. We imaged pericyte-labeled transgenic mice with in vivo two-photon microscopy to examine the relationship between pericytes and blood plasma leakage during photothrombotic occlusion of cortical capillaries. Upon cessation of capillary flow, we observed that plasma leakage occurred with three times greater frequency in regions where pericyte somata adjoined the endothelium. Pericyte somata covered only 7% of the total capillary length in cortex, indicating that a disproportionate amount of leakage occurred from a small fraction of the capillary bed. Plasma leakage was preceded by rapid activation of matrix metalloproteinase (MMP) at pericyte somata, which was visualized at high resolution in vivo using a fluorescent probe for matrix metalloproteinase-2/9 activity, fluorescein isothiocyanate (FITC)-gelatin. Coinjection of an MMP-9 inhibitor, but not an MMP-2 inhibitor, reduced pericyte-associated FITC-gelatin fluorescence and plasma leakage. These results suggest that pericytes contribute to rapid and localized proteolytic degradation of the BBB during cerebral ischemia. SIGNIFICANCE STATEMENT Pericytes are a key component of the neurovascular unit and are essential for normal BBB function. However, during acute ischemia, we find that pericytes are involved in creating rapid and heterogeneous BBB disruption in the capillary bed. The mechanism by which pericytes contribute to BBB damage warrants further investigation, as it may yield new therapeutic targets for acute stroke injury and other neurological diseases involving capillary flow impairment. PMID:28053036

Prototyping of Poly(dimethylsiloxane) Interfaces for Flow Gating, Reagent Mixing, and Tubing Connection in Capillary Electrophoresis

PubMed Central

Zhang, Qiyang; Gong, Maojun

2014-01-01

Integrated microfluidic systems coupled with electrophoretic separations have broad application in biological and chemical analysis. Interfaces for the connection of various functional parts play a major role in the performance of a system. Here we developed a rapid prototyping method to fabricate monolithic poly(dimethylsiloxane) (PDMS) Interfaces for flow-gated injection, online reagent mixing, and tube-to-tube connection in an integrated capillary electrophoresis (CE) system. The basic idea was based on the properties of PDMS: elasticity, transparency, and suitability for prototyping. The molds for these interfaces were prepared by using commercially available stainless steel wires and nylon lines or silica capillaries. A steel wire was inserted through the diameter of a nylon line and a cross format was obtained as the mold for PDMS casting of flow gates and 4-way mixers. These interfaces accommodated tubing connection through PDMS elasticity and provided easy visual trouble shooting. The flow gate used smaller channel diameters thus reducing flow rate by 25 fold for effective gating compared with mechanically machined counterparts. Both PDMS mixers and the tube-to-tube connectors could minimize the sample dead volume by using an appropriate capillary configuration. As a whole, the prototyped PDMS interfaces are reusable, inexpensive, convenient for connection, and robust when integrated with the CE detection system. Therefore, these interfaces could see potential applications in CE and CE-coupled systems. PMID:24331370

Heuristic approach to capillary pressures averaging

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

Coca, B.P.

1980-10-01

Several methods are available to average capillary pressure curves. Among these are the J-curve and regression equations of the wetting-fluid saturation in porosity and permeability (capillary pressure held constant). While the regression equation seem completely empiric, the J-curve method seems to be theoretically sound due to its expression based on a relation between the average capillary radius and the permeability-porosity ratio. An analysis is given of each of these methods.

Enhanced Microchip Electrophoresis Separations Combined with Electrochemical Detection Utilizing a Capillary Embedded in Polystyrene.

PubMed

Mehl, Benjamin T; Martin, R Scott

2018-01-07

The ability to use microchip-based electrophoresis for fast, high-throughput separations provides researchers with a tool for close-to real time analysis of biological systems. While PDMS-based electrophoresis devices are popular, the separation efficiency is often an issue due to the hydrophobic nature of PDMS. In this study, a hybrid microfluidic capillary device was fabricated to utilize the positive features of PDMS along with the electrophoretic performance of fused silica. A capillary loop was embedded in a polystyrene base that can be coupled with PDMS microchannels at minimal dead volume interconnects. A method for cleaning out the capillaries after a wet-polishing step was devised through the use of 3D printed syringe attachment. By comparing the separation efficiency of fluorescein and CBI-glycine with both a PDMS-based serpentine device and the embedded capillary loop device, it was shown that the embedded capillary loop device maintained higher theoretical plates for both analytes. A Pd decoupler with a carbon or Pt detection electrode were embedded along with the loop allowing integration of the electrophoretic separation with electrochemical detection. A series of catecholamines were separated to show the ability to resolve similar analytes and detect redox active species. The release of dopamine and norepinephrine from PC 12 cells was also analyzed showing the compatibility of these improved microchip separations with high ionic cell buffers associated with cell culture.

The fabrication of integrated carbon pipes with sub-micron diameters

NASA Astrophysics Data System (ADS)

Kim, B. M.; Murray, T.; Bau, H. H.

2005-08-01

A method for fabricating integrated carbon pipes (nanopipettes) of sub-micron diameters and tens of microns in length is demonstrated. The carbon pipes are formed from a template consisting of the tip of a pulled alumino-silicate glass capillary coated with carbon deposited from a vapour phase. This method renders carbon nanopipettes without the need for ex situ assembly and facilitates parallel production of multiple carbon-pipe devices. An electric-field-driven transfer of ions in a KCl solution through the integrated carbon pipes exhibits nonlinear current-voltage (I-V) curves, markedly different from the Ohmic I-V curves observed in glass pipettes under similar conditions. The filling of the nanopipette with fluorescent suspension is also demonstrated.

Integrated optics to improve resolution on multiple configuration

NASA Astrophysics Data System (ADS)

Liu, Hua; Ding, Quanxin; Guo, Chunjie; Zhou, Liwei

2015-04-01

Inspired to in order to reveal the structure to improve imaging resolution, further technical requirement is proposed in some areas of the function and influence on the development of multiple configuration. To breakthrough diffraction limit, smart structures are recommended as the most efficient and economical method, while by used to improve the system performance, especially on signal to noise ratio and resolution. Integrated optics were considered in the selection, with which typical multiple configuration, by use the method of simulation experiment. Methodology can change traditional design concept and to develop the application space. Our calculations using multiple matrix transfer method, also the correlative algorithm and full calculations, show the expected beam shaping through system and, in particular, the experimental results will support our argument, which will be reported in the presentation.

Single-bead arrays for fluorescence-based immunoassays on capillary-driven microfluidic chips

NASA Astrophysics Data System (ADS)

Temiz, Yuksel; Lim, Michel; Delamarche, Emmanuel

2016-03-01

We report a concept for the simple fabrication of easy-to-use chips for immunoassays in the context of point-of-care diagnostics. The chip concept comprises mainly three features: (1) the efficient integration of reagents using beads functionalized with receptors, (2) the generation of capillary-driven liquid flows without using external pumps, and (3) a high-sensitivity detection of analytes using fluorescence microscopy. We fabricated prototype chips using dry etching of Si wafers. 4.5-μm-diameter beads were integrated into hexagonal arrays by sedimentation and removing the excess using a stream of water. We studied the effect of different parameters and showed that array occupancies from 30% to 50% can be achieved by pipetting a 250 nL droplet of 1% bead solution and allowing the beads sediment for 3 min. Chips with integrated beads were sealed using a 50-μm-thick dry-film resist laminated at 45 °C. Liquids pipetted to loading pads were autonomously pulled by capillary pumps at a rate of 0.35 nL s-1 for about 30 min. We studied ligand-receptor interactions and binding kinetics using time-lapse fluorescence microscopy and demonstrated a 5 pM limit of detection (LOD) for an anti-biotin immunoassay. As a clinically-relevant example, we implemented an immunoassay to detect prostate specific antigen (PSA) and showed an LOD of 108 fM (i.e. 3.6 pg mL-1). While a specific implementation is provided here for the detection of PSA, we believe that combining capillary-driven microfluidics with arrays of single beads and fluorescence readout to be very flexible and sufficiently sensitive for the detection of other clinically-relevant analytes.

Mach-like capillary-gravity wakes.

PubMed

Moisy, Frédéric; Rabaud, Marc

2014-08-01

We determine experimentally the angle α of maximum wave amplitude in the far-field wake behind a vertical surface-piercing cylinder translated at constant velocity U for Bond numbers Bo(D)=D/λ(c) ranging between 0.1 and 4.2, where D is the cylinder diameter and λ(c) the capillary length. In all cases the wake angle is found to follow a Mach-like law at large velocity, α∼U(-1), but with different prefactors depending on the value of Bo(D). For small Bo(D) (large capillary effects), the wake angle approximately follows the law α≃c(g,min)/U, where c(g,min) is the minimum group velocity of capillary-gravity waves. For larger Bo(D) (weak capillary effects), we recover a law α∼√[gD]/U similar to that found for ship wakes at large velocity [Rabaud and Moisy, Phys. Rev. Lett. 110, 214503 (2013)]. Using the general property of dispersive waves that the characteristic wavelength of the wave packet emitted by a disturbance is of order of the disturbance size, we propose a simple model that describes the transition between these two Mach-like regimes as the Bond number is varied. We show that the new capillary law α≃c(g,min)/U originates from the presence of a capillary cusp angle (distinct from the usual gravity cusp angle), along which the energy radiated by the disturbance accumulates for Bond numbers of order of unity. This model, complemented by numerical simulations of the surface elevation induced by a moving Gaussian pressure disturbance, is in qualitative agreement with experimental measurements.

Determining the imaging plane of a retinal capillary layer in adaptive optical imaging

NASA Astrophysics Data System (ADS)

Yang, Le-Bao; Hu, Li-Fa; Li, Da-Yu; Cao, Zhao-Liang; Mu, Quan-Quan; Ma, Ji; Xuan, Li

2016-09-01

Even in the early stage, endocrine metabolism disease may lead to micro aneurysms in retinal capillaries whose diameters are less than 10 μm. However, the fundus cameras used in clinic diagnosis can only obtain images of vessels larger than 20 μm in diameter. The human retina is a thin and multiple layer tissue, and the layer of capillaries less than 10 μm in diameter only exists in the inner nuclear layer. The layer thickness of capillaries less than 10 μm in diameter is about 40 μm and the distance range to rod&cone cell surface is tens of micrometers, which varies from person to person. Therefore, determining reasonable capillary layer (CL) position in different human eyes is very difficult. In this paper, we propose a method to determine the position of retinal CL based on the rod&cone cell layer. The public positions of CL are recognized with 15 subjects from 40 to 59 years old, and the imaging planes of CL are calculated by the effective focal length of the human eye. High resolution retinal capillary imaging results obtained from 17 subjects with a liquid crystal adaptive optics system (LCAOS) validate our method. All of the subjects’ CLs have public positions from 127 μm to 147 μm from the rod&cone cell layer, which is influenced by the depth of focus. Project supported by the National Natural Science Foundation of China (Grant Nos. 11174274, 11174279, 61205021, 11204299, 61475152, and 61405194).

Capillary electrophoresis of inorganic anions.

PubMed

Kaniansky, D; Masár, M; Marák, J; Bodor, R

1999-02-26

This review deals with the separation mechanisms applied to the separation of inorganic anions by capillary electrophoresis (CE) techniques. It covers various CE techniques that are suitable for the separation and/or determination of inorganic anions in various matrices, including capillary zone electrophoresis, micellar electrokinetic chromatography, electrochromatography and capillary isotachophoresis. Detection and sample preparation techniques used in CE separations are also reviewed. An extensive part of this review deals with applications of CE techniques in various fields (environmental, food and plant materials, biological and biomedical, technical materials and industrial processes). Attention is paid to speciations of anions of arsenic, selenium, chromium, phosphorus, sulfur and halogen elements by CE.

Small capillary pumped AMTEC systems

NASA Astrophysics Data System (ADS)

Hunt, Thomas K.; Sievers, Robert K.; Butkiewicz, David A.; Pantolin, Jan E.; Ivanenok, Joseph F.

1993-01-01

Alkali Metal Thermoelectric Converter (AMTEC) systems offer significant potential advantages for space power. Recent experiments have shown that electromagnetic pumps can operate with a negative priming head and so may be suitable for space applications in microgravity (Hunt et al. 1992). Capillary pumped cells offer an alternative approach to microgravity compatibility. We have designed, built, and operated capillary pumped AMTEC cells in various orientations with respect to gravity in order to provide a presumptive demonstration of zero-G capability (Sievers et al. 1992). We report lifetime and performance data for these capillary pumped AMTEC cells. Progress on other issues relating to space flight testing of AMTEC systems is also discussed.

Disposable pen-shaped capillary gel electrophoresis cartridge for fluorescence detection of bio-molecules

NASA Astrophysics Data System (ADS)

Amirkhanian, Varoujan; Tsai, Shou-Kuan

2014-03-01

We introduce a novel and cost-effective capillary gel electrophoresis (CGE) system utilizing disposable pen-shaped gelcartridges for highly efficient, high speed, high throughput fluorescence detection of bio-molecules. The CGE system has been integrated with dual excitation and emission optical-fibers with micro-ball end design for fluorescence detection of bio-molecules separated and detected in a disposable pen-shaped capillary gel electrophoresis cartridge. The high-performance capillary gel electrophoresis (CGE) analyzer has been optimized for glycoprotein analysis type applications. Using commercially available labeling agent such as ANTS (8-aminonapthalene-1,3,6- trisulfonate) as an indicator, the capillary gel electrophoresis-based glycan analyzer provides high detection sensitivity and high resolving power in 2-5 minutes of separations. The system can hold total of 96 samples, which can be automatically analyzed within 4-5 hours. This affordable fiber optic based fluorescence detection system provides fast run times (4 minutes vs. 20 minutes with other CE systems), provides improved peak resolution, good linear dynamic range and reproducible migration times, that can be used in laboratories for high speed glycan (N-glycan) profiling applications. The CGE-based glycan analyzer will significantly increase the pace at which glycoprotein research is performed in the labs, saving hours of preparation time and assuring accurate, consistent and economical results.

Miniaturised electrically actuated high pressure injection valve for portable capillary liquid chromatography.

PubMed

Li, Yan; Pace, Kirsten; Nesterenko, Pavel N; Paull, Brett; Stanley, Roger; Macka, Mirek

2018-04-01

A miniaturised high pressure 6-port injection valve has been designed and evaluated for its performance in order to facilitate the development of portable capillary high performance liquid chromatography (HPLC). The electrically actuated valve features a very small size (65 × 19 × 19mm) and light weight (33g), and therefore can be easily integrated in a miniaturised modular capillary LC system suited for portable field analysis. The internal volume of the injection valve was determined as 98 nL. The novel conical shape of the stator and rotor and the spring-loaded rotor performed well up to 32MPa (4641psi), the maximum operating pressure investigated. Suitability for application was demonstrated using a miniaturised capillary LC system applied to the chromatographic separation of a mixture of biogenic amines and common cations. The RSD (relative standard deviation) values of retention times and peak areas of 6 successive runs were 0.5-0.7% and 1.8-2.8% for the separation of biogenic amines, respectively, and 0.1-0.2% and 2.1-3.0% for the separation of cations, respectively. This performance was comparable with bench-top HPLC systems thus demonstrating the applicability of the valve for use in portable and miniaturised capillary HPLC systems. Copyright © 2017 Elsevier B.V. All rights reserved.

Capillary density: An important parameter in nailfold capillaroscopy.

PubMed

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.

Scale-dependent coupling of hysteretic capillary pressure, trapping, and fluid mobilities

NASA Astrophysics Data System (ADS)

Doster, F.; Celia, M. A.; Nordbotten, J. M.

2012-12-01

Many applications of multiphase flow in porous media, including CO2-storage and enhanced oil recovery, require mathematical models that span a large range of length scales. In the context of numerical simulations, practical grid sizes are often on the order of tens of meters, thereby de facto defining a coarse model scale. Under particular conditions, it is possible to approximate the sub-grid-scale distribution of the fluid saturation within a grid cell; that reconstructed saturation can then be used to compute effective properties at the coarse scale. If both the density difference between the fluids and the vertical extend of the grid cell are large, and buoyant segregation within the cell on a sufficiently shorte time scale, then the phase pressure distributions are essentially hydrostatic and the saturation profile can be reconstructed from the inferred capillary pressures. However, the saturation reconstruction may not be unique because the parameters and parameter functions of classical formulations of two-phase flow in porous media - the relative permeability functions, the capillary pressure -saturation relationship, and the residual saturations - show path dependence, i.e. their values depend not only on the state variables but also on their drainage and imbibition histories. In this study we focus on capillary pressure hysteresis and trapping and show that the contribution of hysteresis to effective quantities is dependent on the vertical length scale. By studying the transition from the two extreme cases - the homogeneous saturation distribution for small vertical extents and the completely segregated distribution for large extents - we identify how hysteretic capillary pressure at the local scale induces hysteresis in all coarse-scale quantities for medium vertical extents and finally vanishes for large vertical extents. Our results allow for more accurate vertically integrated modeling while improving our understanding of the coupling of capillary

Microgravity Investigation of Capillary Driven Imbibition

NASA Astrophysics Data System (ADS)

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.

Polymer microfluidic device replacing fluids using only capillary force

NASA Astrophysics Data System (ADS)

Chung, Kwang Hyo; Lee, Dae Sik; Yang, Haesik; Kim, Sung Jin; Pyo, Hyun Bong

2005-02-01

A novel polymer microfluidic device for self-wash using only capillary force is presented. A liquid filled in a reaction chamber is replaced by another liquid with no external actuation. All the fluidic actuations in the device is pre-programmed about time and sequence, and accomplished by capillary force naturally. Careful design is necessary for exact actions. The fluidic conduits were designed by the newly derived theoretical equations about the capillary stop pressure and flow time. Simulations using CFD-ACE+ were conducted to check the validity of theory and the performance of the chip. These analytic results were consistent with experimental ones. The chip was made of polymers for the purpose of single use and low price. It was fabricated by sealing the hot-embossed PMMA substrate with a PET film. For simpler fabrication, the chip was of a single height. The embossing master was produced from a nickel-electroplating on a SU8-patterned Ni-plate followed by CMP. The contact angles of liquids on substrates were manipulated through the mixing of surfactants, and the temporal variations were monitored for a more exact design. The real actuation steps in experiment revealed the stable performance of selfwash, and coincided well with the designed ones. The presented microfluidic method can be applicable to other LOCs of special purposes through simple modification. For example, array or serial types would be possible for multiple selfwashes.

Geometry-induced phase transition in fluids: Capillary prewetting

NASA Astrophysics Data System (ADS)

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 Tcw. 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>Tcw, 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.

Numerical Simulation of Unsteady Blood Flow through Capillary Networks.

PubMed

Davis, J M; Pozrikidis, C

2011-08-01

A numerical method is implemented for computing unsteady blood flow through a branching capillary network. The evolution of the discharge hematocrit along each capillary segment is computed by integrating in time a one-dimensional convection equation using a finite-difference method. The convection velocity is determined by the local and instantaneous effective capillary blood viscosity, while the tube to discharge hematocrit ratio is deduced from available correlations. Boundary conditions for the discharge hematocrit at divergent bifurcations arise from the partitioning law proposed by Klitzman and Johnson involving a dimensionless exponent, q≥1. When q=1, the cells are partitioned in proportion to the flow rate; as q tends to infinity, the cells are channeled into the branch with the highest flow rate. Simulations are performed for a tree-like, perfectly symmetric or randomly perturbed capillary network with m generations. When the tree involves more than a few generations, a supercritical Hopf bifurcation occurs at a critical value of q, yielding spontaneous self-sustained oscillations in the absence of external forcing. A phase diagram in the m-q plane is presented to establish conditions for unsteady flow, and the effect of various geometrical and physical parameters is examined. For a given network tree order, m, oscillations can be induced for a sufficiently high value of q by increasing the apparent intrinsic viscosity, decreasing the ratio of the vessel diameter from one generation to the next, or by decreasing the diameter of the terminal vessels. With other parameters fixed, oscillations are inhibited by increasing m. The results of the continuum model are in excellent agreement with the predictions of a discrete model where the motion of individual cells is followed from inlet to outlet.

HMC algorithm with multiple time scale integration and mass preconditioning

NASA Astrophysics Data System (ADS)

Urbach, C.; Jansen, K.; Shindler, A.; Wenger, U.

2006-01-01

We present a variant of the HMC algorithm with mass preconditioning (Hasenbusch acceleration) and multiple time scale integration. We have tested this variant for standard Wilson fermions at β=5.6 and at pion masses ranging from 380 to 680 MeV. We show that in this situation its performance is comparable to the recently proposed HMC variant with domain decomposition as preconditioner. We give an update of the "Berlin Wall" figure, comparing the performance of our variant of the HMC algorithm to other published performance data. Advantages of the HMC algorithm with mass preconditioning and multiple time scale integration are that it is straightforward to implement and can be used in combination with a wide variety of lattice Dirac operators.

On Capillary Rise and Nucleation

ERIC Educational Resources Information Center

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.)

A simple and inexpensive on-column frit fabrication method for fused-silica capillaries for increased capacity and versatility in LC-MS/MS applications.

PubMed

Wang, Ling-Chi; Okitsu, Cindy Yen; Kochounian, Harold; Rodriguez, Anthony; Hsieh, Chih-Lin; Zandi, Ebrahim

2008-05-01

A modified sol-gel method for a one-step on-column frit preparation for fused-silica capillaries and its utility for peptide separation in LC-MS/MS is described. This method is inexpensive, reproducible, and does not require specialized equipments. Because the frit fabrication process does not damage polyimide coating, the frit-fabricated column can be tightly connected on-line for high pressure LC. These columns can replace any capillary liquid transfer tubing without any specialized connections up-stream of a spray tip column. Therefore multiple columns with different phases can be connected in series for one- or multiple-dimensional chromatography.

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

PubMed

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.

Content Integration across Multiple Documents Reduces Memory for Sources

ERIC Educational Resources Information Center

Braasch, Jason L. G.; McCabe, Rebecca M.; Daniel, Frances

2016-01-01

The current experiments systematically examined semantic content integration as a mechanism for explaining source inattention and forgetting when reading-to-remember multiple texts. For all 3 experiments, degree of semantic overlap was manipulated amongst messages provided by various information sources. In Experiment 1, readers' source…

EIF2AK4 Mutations in Pulmonary Capillary Hemangiomatosis

PubMed Central

Best, D. Hunter; Sumner, Kelli L.; Austin, Eric D.; Chung, Wendy K.; Brown, Lynette M.; Borczuk, Alain C.; Rosenzweig, Erika B.; Bayrak-Toydemir, Pinar; Mao, Rong; Cahill, Barbara C.; Tazelaar, Henry D.; Leslie, Kevin O.; Hemnes, Anna R.; Robbins, Ivan M.

2014-01-01

Background: Pulmonary capillary hemangiomatosis (PCH) is a rare disease of capillary proliferation of unknown cause and with a high mortality. Families with multiple affected individuals with PCH suggest a heritable cause although the genetic etiology remains unknown. Methods: We used exome sequencing to identify a candidate gene for PCH in a family with two affected brothers. We then screened 11 unrelated patients with familial (n = 1) or sporadic (n = 10) PCH for mutations. Results: Using exome sequencing, we identified compound mutations in eukaryotic translation initiation factor 2 α kinase 4 (EIF2AK4) (formerly known as GCN2) in both affected brothers. Both parents and an unaffected sister were heterozygous carriers. In addition, we identified two EIF2AK4 mutations in each of two of 10 unrelated individuals with sporadic PCH. EIF2AK4 belongs to a family of kinases that regulate angiogenesis in response to cellular stress. Conclusions: Mutations in EIF2AK4 are likely to cause autosomal-recessive PCH in familial and some nonfamilial cases. PMID:24135949

Tantala-based sol-gel coating for capillary microextraction on-line coupled to high-performance liquid chromatography.

PubMed

Tran, MinhPhuong; Turner, Erica B; Segro, Scott S; Fang, Li; Seyyal, Emre; Malik, Abdul

2017-11-03

A sol-gel organic-inorganic hybrid sorbent, consisting of chemically integrated tantalum (V) ethoxide (TaEO) and polypropylene glycol methacrylate (PPGM), was developed for capillary microextraction (CME). The sol-gel sorbent was synthesized within a fused silica capillary through hydrolytic polycondensation of TaEO and chemical incorporation of PPGM into the evolving sol-gel tantala network. A part of the organic-inorganic hybrid sol-gel network evolving in the vicinity of the capillary walls had favorable conditions to get chemically bonded to the silanol groups on the capillary surface forming a surface-bonded coating. The newly developed sol-gel sorbent was employed to isolate and enrich a variety of analytes from aqueous samples for on-line analysis by high-performance liquid chromatography (HPLC) equipped with a UV detector. CME was performed on aqueous samples containing trace concentrations of analytes representing polycyclic aromatic hydrocarbons, ketones, alcohols, amines, nucleosides, and nucleotides. This sol-gel hybrid coating provided efficient extraction with CME-HPLC detection limits ranging from 4.41pM to 28.19 pM. Due to direct chemical bonding between the sol-gel sorbent coating and the fused silica capillary inner surface, this sol-gel sorbent exhibited enhanced solvent stability. The sol-gel tantala-based sorbent also exhibited excellent pH stability over a wide pH range (pH 0-pH 14). Furthermore, it displayed great performance reproducibility in CME-HPLC providing run-to-run HPLC peak area relative standard deviation (RSD) values between 0.23% and 3.83%. The capillary-to-capillary RSD (n=3), characterizing capillary preparation method reproducibility, ranged from 0.24% to 4.11%. The results show great performance consistency and application potential for the sol-gel tantala-PPGM sorbent in various fields including biomedical, pharmaceutical, and environmental areas. Copyright © 2017 Elsevier B.V. All rights reserved.

Influence of local capillary trapping on containment system effectiveness

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

Bryant, Steven

2014-03-31

Immobilization of CO 2 injected into deep subsurface storage reservoirs is a critical component of risk assessment for geologic CO 2 storage (GCS). Local capillary trapping (LCT) is a recently established mode of immobilization that arises when CO 2 migrates due to buoyancy through heterogeneous storage reservoirs. This project sought to assess the amount and extent of LCT expected in storage formations under a range of injection conditions, and to confirm the persistence of LCT if the seal overlying the reservoir were to lose its integrity. Numerical simulation using commercial reservoir simulation software was conducted to assess the influence ofmore » injection. Laboratory experiments, modeling and numerical simulation were conducted to assess the effect of compromised seal integrity. Bench-scale (0.6 m by 0.6 m by 0.03 m) experiments with surrogate fluids provided the first empirical confirmation of the key concepts underlying LCT: accumulation of buoyant nonwetting phase at above residual saturations beneath capillary barriers in a variety of structures, which remains immobile under normal capillary pressure gradients. Immobilization of above-residual saturations is a critical distinction between LCT and the more familiar “residual saturation trapping.” To estimate the possible extent of LCT in a storage reservoir an algorithm was developed to identify all potential local traps, given the spatial distribution of capillary entry pressure in the reservoir. The algorithm assumes that the driving force for CO 2 migration can be represented as a single value of “critical capillary entry pressure” P c,entry crit, such that cells with capillary entry pressure greater/less than P c,entry crit act as barriers/potential traps during CO 2 migration. At intermediate values of P c,entry crit, the barrier regions become more laterally extensive in the reservoir, approaching a percolation threshold while non-barrier regions remain numerous. The maximum possible

[Recent advances and applications of capillary electrochromatography and pressurized capillary electrochromatography].

PubMed

Wu, Yi; Zhang, Xiaohui; Wei, Juan; Xue, Yunyun; Bahatibieke, Marjan; Wang, Yan; Yan, Chao

2009-09-01

Capillary electrochromatography (CEC), in which electroosmotic flow (EOF) created from the electrical double layer is made to act as a pump to drive the mobile phase in a capillary column packed with micro-particulates or coated with stationary phase. Both neutral and charged species can be resolved by CEC. It has been demonstrated that the efficiency of a separation obtained by electroosmotic propulsion is superior to that obtained by pressure-driven flow (as is the case in HPLC). CEC combines the best features of CE and versatile selectivity and large sample capacity of HPLC, promising high efficiency, high resolution, high selectivity and high peak capacity. However, in practice, when CEC is used without pressure, often used on a commercial CE instrument, there are problems and difficulties associated with bubbles formation and column dry-out. These difficulties can be overcome by a pressurized CEC (pCEC) system, in which a supplementary pressure is applied to the column in addition to the EOF. In such a system, a pressure can be applied to the capillary column to suppress bubbles formation. Quantitative sample introduction in pCEC can be easily achieved through a rotary-type injector. Most importantly, it is amenable for a solvent gradient mode, similar to that in HPLC, by programming the composition of mobile phase. The article brings a comprehensive survey of recent development of CEC and pCEC, including the development of instrumentation, capillary columns and stationary phase as well as CEC and pCEC applications in life science, biotechnology, pharmaceutical analysis, food safety and environmental security. Prospects for CEC and pCEC development and application are also discussed.

Simplifying Differential Equations for Multiscale Feynman Integrals beyond Multiple Polylogarithms.

PubMed

Adams, Luise; Chaubey, Ekta; Weinzierl, Stefan

2017-04-07

In this Letter we exploit factorization properties of Picard-Fuchs operators to decouple differential equations for multiscale Feynman integrals. The algorithm reduces the differential equations to blocks of the size of the order of the irreducible factors of the Picard-Fuchs operator. As a side product, our method can be used to easily convert the differential equations for Feynman integrals which evaluate to multiple polylogarithms to an ϵ form.

Automated one-step DNA sequencing based on nanoliter reaction volumes and capillary electrophoresis.

PubMed

Pang, H M; Yeung, E S

2000-08-01

An integrated system with a nano-reactor for cycle-sequencing reaction coupled to on-line purification and capillary gel electrophoresis has been demonstrated. Fifty nanoliters of reagent solution, which includes dye-labeled terminators, polymerase, BSA and template, was aspirated and mixed with the template inside the nano-reactor followed by cycle-sequencing reaction. The reaction products were then purified by a size-exclusion chromatographic column operated at 50 degrees C followed by room temperature on-line injection of the DNA fragments into a capillary for gel electrophoresis. Over 450 bases of DNA can be separated and identified. As little as 25 nl reagent solution can be used for the cycle-sequencing reaction with a slightly shorter read length. Significant savings on reagent cost is achieved because the remaining stock solution can be reused without contamination. The steps of cycle sequencing, on-line purification, injection, DNA separation, capillary regeneration, gel-filling and fluidic manipulation were performed with complete automation. This system can be readily multiplexed for high-throughput DNA sequencing or PCR analysis directly from templates or even biological materials.

Biomimetic Unidirectional Capillary Action

NASA Astrophysics Data System (ADS)

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.

RASA1 analysis guides management in a family with capillary malformation-arteriovenous malformation

PubMed Central

Flore, Leigh Anne; Leon, Eyby; Maher, Tom A.; Milunsky, Jeff M.

2012-01-01

Capillary malformation-arteriovenous malformation (CM-AVM; MIM 60354) is an autosomal dominant disorder characterized by multifocal cutaneous capillary malformations, often in association with fast-flow vascular lesions, which may be cutaneous, subcutaneous, intramuscular, intraosseus, or cerebral arteriovenous malformations or arteriovenous fistulas. CM-AVM results from heterozygous mutations in the RASA1 gene. Capillary malformations of the skin are common, and clinical examination alone may not be able to definitively diagnose-or exclude- CM-AVM. We report a family in which the proband was initially referred for a genetic evaluation in the neonatal period because of the presence of a cardiac murmur and minor dysmorphic features. Both he and his mother were noted to have multiple capillary malformations on the face, head, and extremities. Echocardiography revealed dilated head and neck vessels and magnetic resonance imaging and angiography of the brain revealed a large infratentorial arteriovenous fistula, for which he has had two embolization procedures. RASA1 sequence analysis revealed a heterozygous mutation, confirming his diagnosis of CM-AVM. We established targeted mutation analysis for the proband's mother and sister, the latter of whom is a healthy 3-year-old whose only cutaneous finding is a facial capillary malformation. This revealed that the proband's mother is also heterozygous for the RASA1 mutation, but his sister is negative. Consequently, his mother will undergo magnetic resonance imaging and angiography screening for intracranial and spinal fast-flow lesions, while his sister will require no imaging or serial evaluations. Targeted mutation analysis has been offered to additional maternal family members. This case illustrates the benefit of molecular testing in diagnosis and making screening recommendations for families with CM-AVM. PMID:27625812

RASA1 analysis guides management in a family with capillary malformation-arteriovenous malformation.

PubMed

Flore, Leigh Anne; Leon, Eyby; Maher, Tom A; Milunsky, Jeff M

2012-06-01

Capillary malformation-arteriovenous malformation (CM-AVM; MIM 60354) is an autosomal dominant disorder characterized by multifocal cutaneous capillary malformations, often in association with fast-flow vascular lesions, which may be cutaneous, subcutaneous, intramuscular, intraosseus, or cerebral arteriovenous malformations or arteriovenous fistulas. CM-AVM results from heterozygous mutations in the RASA1 gene. Capillary malformations of the skin are common, and clinical examination alone may not be able to definitively diagnose-or exclude- CM-AVM. We report a family in which the proband was initially referred for a genetic evaluation in the neonatal period because of the presence of a cardiac murmur and minor dysmorphic features. Both he and his mother were noted to have multiple capillary malformations on the face, head, and extremities. Echocardiography revealed dilated head and neck vessels and magnetic resonance imaging and angiography of the brain revealed a large infratentorial arteriovenous fistula, for which he has had two embolization procedures. RASA1 sequence analysis revealed a heterozygous mutation, confirming his diagnosis of CM-AVM. We established targeted mutation analysis for the proband's mother and sister, the latter of whom is a healthy 3-year-old whose only cutaneous finding is a facial capillary malformation. This revealed that the proband's mother is also heterozygous for the RASA1 mutation, but his sister is negative. Consequently, his mother will undergo magnetic resonance imaging and angiography screening for intracranial and spinal fast-flow lesions, while his sister will require no imaging or serial evaluations. Targeted mutation analysis has been offered to additional maternal family members. This case illustrates the benefit of molecular testing in diagnosis and making screening recommendations for families with CM-AVM.

Measurement of Capillary Radius and Contact Angle within Porous Media.

PubMed

Ravi, Saitej; Dharmarajan, Ramanathan; Moghaddam, Saeed

2015-12-01

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

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

PubMed

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

2015-10-15

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

On the method of Ermakov and Zolotukhin for multiple integration

NASA Technical Reports Server (NTRS)

Cranley, R.; Patterson, T. N. L.

1971-01-01

By introducing the idea of pseudo-implementation, a practical assessment of the method for multiple integration is made. The performance of the method is found to be unimpressive in comparison with a recent regression method.

Integrated presentation of ecological risk from multiple stressors

NASA Astrophysics Data System (ADS)

Goussen, Benoit; Price, Oliver R.; Rendal, Cecilie; Ashauer, Roman

2016-10-01

Current environmental risk assessments (ERA) do not account explicitly for ecological factors (e.g. species composition, temperature or food availability) and multiple stressors. Assessing mixtures of chemical and ecological stressors is needed as well as accounting for variability in environmental conditions and uncertainty of data and models. Here we propose a novel probabilistic ERA framework to overcome these limitations, which focusses on visualising assessment outcomes by construct-ing and interpreting prevalence plots as a quantitative prediction of risk. Key components include environmental scenarios that integrate exposure and ecology, and ecological modelling of relevant endpoints to assess the effect of a combination of stressors. Our illustrative results demonstrate the importance of regional differences in environmental conditions and the confounding interactions of stressors. Using this framework and prevalence plots provides a risk-based approach that combines risk assessment and risk management in a meaningful way and presents a truly mechanistic alternative to the threshold approach. Even whilst research continues to improve the underlying models and data, regulators and decision makers can already use the framework and prevalence plots. The integration of multiple stressors, environmental conditions and variability makes ERA more relevant and realistic.

Integrated presentation of ecological risk from multiple stressors.

PubMed

Goussen, Benoit; Price, Oliver R; Rendal, Cecilie; Ashauer, Roman

2016-10-26

Current environmental risk assessments (ERA) do not account explicitly for ecological factors (e.g. species composition, temperature or food availability) and multiple stressors. Assessing mixtures of chemical and ecological stressors is needed as well as accounting for variability in environmental conditions and uncertainty of data and models. Here we propose a novel probabilistic ERA framework to overcome these limitations, which focusses on visualising assessment outcomes by construct-ing and interpreting prevalence plots as a quantitative prediction of risk. Key components include environmental scenarios that integrate exposure and ecology, and ecological modelling of relevant endpoints to assess the effect of a combination of stressors. Our illustrative results demonstrate the importance of regional differences in environmental conditions and the confounding interactions of stressors. Using this framework and prevalence plots provides a risk-based approach that combines risk assessment and risk management in a meaningful way and presents a truly mechanistic alternative to the threshold approach. Even whilst research continues to improve the underlying models and data, regulators and decision makers can already use the framework and prevalence plots. The integration of multiple stressors, environmental conditions and variability makes ERA more relevant and realistic.

Integrated presentation of ecological risk from multiple stressors

PubMed Central

Goussen, Benoit; Price, Oliver R.; Rendal, Cecilie; Ashauer, Roman

2016-01-01

Current environmental risk assessments (ERA) do not account explicitly for ecological factors (e.g. species composition, temperature or food availability) and multiple stressors. Assessing mixtures of chemical and ecological stressors is needed as well as accounting for variability in environmental conditions and uncertainty of data and models. Here we propose a novel probabilistic ERA framework to overcome these limitations, which focusses on visualising assessment outcomes by construct-ing and interpreting prevalence plots as a quantitative prediction of risk. Key components include environmental scenarios that integrate exposure and ecology, and ecological modelling of relevant endpoints to assess the effect of a combination of stressors. Our illustrative results demonstrate the importance of regional differences in environmental conditions and the confounding interactions of stressors. Using this framework and prevalence plots provides a risk-based approach that combines risk assessment and risk management in a meaningful way and presents a truly mechanistic alternative to the threshold approach. Even whilst research continues to improve the underlying models and data, regulators and decision makers can already use the framework and prevalence plots. The integration of multiple stressors, environmental conditions and variability makes ERA more relevant and realistic. PMID:27782171

NEXT Propellant Management System Integration With Multiple Ion Thrusters

NASA Technical Reports Server (NTRS)

Sovey, James S.; Soulas, George C.; Herman, Daniel A.

2011-01-01

As a critical part of the NEXT test validation process, a multiple-string integration test was performed on the NEXT propellant management system and ion thrusters. The objectives of this test were to verify that the PMS is capable of providing stable flow control to multiple thrusters operating over the NEXT system throttling range and to demonstrate to potential users that the NEXT PMS is ready for transition to flight. A test plan was developed for the sub-system integration test for verification of PMS and thruster system performance and functionality requirements. Propellant management system calibrations were checked during the single and multi-thruster testing. The low pressure assembly total flow rates to the thruster(s) were within 1.4 percent of the calibrated support equipment flow rates. The inlet pressures to the main, cathode, and neutralizer ports of Thruster PM1R were measured as the PMS operated in 1-thruster, 2-thruster, and 3-thruster configurations. It was found that the inlet pressures to Thruster PM1R for 2-thruster and 3-thruster operation as well as single thruster operation with the PMS compare very favorably indicating that flow rates to Thruster PM1R were similar in all cases. Characterizations of discharge losses, accelerator grid current, and neutralizer performance were performed as more operating thrusters were added to the PMS. There were no variations in these parameters as thrusters were throttled and single and multiple thruster operations were conducted. The propellant management system power consumption was at a fixed voltage to the DCIU and a fixed thermal throttle temperature of 75 C. The total power consumed by the PMS was 10.0, 17.9, and 25.2 W, respectively, for single, 2-thruster, and 3-thruster operation with the PMS. These sub-system integration tests of the PMS, the DCIU Simulator, and multiple thrusters addressed, in part, the NEXT PMS and propulsion system performance and functionality requirements.

Can the meaning of multiple words be integrated unconsciously?

PubMed

van Gaal, Simon; Naccache, Lionel; Meuwese, Julia D I; van Loon, Anouk M; Leighton, Alexandra H; Cohen, Laurent; Dehaene, Stanislas

2014-05-05

What are the limits of unconscious language processing? Can language circuits process simple grammatical constructions unconsciously and integrate the meaning of several unseen words? Using behavioural priming and electroencephalography (EEG), we studied a specific rule-based linguistic operation traditionally thought to require conscious cognitive control: the negation of valence. In a masked priming paradigm, two masked words were successively (Experiment 1) or simultaneously presented (Experiment 2), a modifier ('not'/'very') and an adjective (e.g. 'good'/'bad'), followed by a visible target noun (e.g. 'peace'/'murder'). Subjects indicated whether the target noun had a positive or negative valence. The combination of these three words could either be contextually consistent (e.g. 'very bad - murder') or inconsistent (e.g. 'not bad - murder'). EEG recordings revealed that grammatical negations could unfold partly unconsciously, as reflected in similar occipito-parietal N400 effects for conscious and unconscious three-word sequences forming inconsistent combinations. However, only conscious word sequences elicited P600 effects, later in time. Overall, these results suggest that multiple unconscious words can be rapidly integrated and that an unconscious negation can automatically 'flip the sign' of an unconscious adjective. These findings not only extend the limits of subliminal combinatorial language processes, but also highlight how consciousness modulates the grammatical integration of multiple words.

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

PubMed

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

2017-09-12

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

Cell adhesion during bullet motion in capillaries.

PubMed

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.

Sheathless interface to match flow rate of capillary electrophoresis with electrospray mass spectrometry using regular-sized capillary.

PubMed

Yin, Yue; Li, Gongyu; Guan, Yafeng; Huang, Guangming

2016-08-01

The flow rate match has been a great challenge when coupling capillary electrophoresis (CE) with electrospray ionization mass spectrometry (ESI-MS). Conventional CE-ESI-MS interfaces used liquid sheath flow, narrowed capillary or additional pressure to meet this requirement; sacrifice of either capillary inner diameter (i.d.) or separation efficiency is often inevitable. Thus, a regular-sized capillary-based sheathless interface would be attractive for flow rate match in CE-MS. The regular-sized capillary-based CE-MS interface was achieved by coupling CE with induced electrospray ionization (iESI) which was stimulated by the fact that the iESI could both achieve flow rate down to 0.2 μL/min and retain ionization efficiency. The CE-iESI-MS interface was completed with an intact separation capillary, outside the outlet end of which a metal electrode was attached for the application of alternating current (ac) high voltage (HV). The feasibility of this CE-iESI-MS interface was demonstrated through the stable total ion chromatograms obtained by continuous CE infusion of tripropylamine with regular-sized capillaries. Tripropylamine and atenolol were separated and detected successfully in phosphate buffer solution (PBS) by CE-iESI-MS using a 50 or 75 μm i.d. capillary. Furthermore, this new interface showed a better signal-to-noise (S/N) of 3 to 7 times enhancement compared with another sheathless CE-ESI-MS interface that using one high voltage for both separation and electrospray when analyzing the mixture of tripropylamine and proline in NH4 OAc buffer. In addition, the reproducibility of this interface gave satisfactory results with relative standard deviation (RSD) in retention time in the range between 1% and 3%. The novel sheathless CE-MS interface introduced here could match conventional electroosmotic flow (EOF) with electrospray which could also preserve the separation efficiency and sensitivity of CE-MS. This newly developed CE-iESI-MS interface was also

21 CFR 864.6150 - Capillary blood collection tube.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Capillary blood collection tube. 864.6150 Section... blood collection tube. (a) Identification. A capillary blood collection tube is a plain or heparinized glass tube of very small diameter used to collect blood by capillary action. (b) Classification. Class I...

21 CFR 864.6150 - Capillary blood collection tube.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Capillary blood collection tube. 864.6150 Section... blood collection tube. (a) Identification. A capillary blood collection tube is a plain or heparinized glass tube of very small diameter used to collect blood by capillary action. (b) Classification. Class I...

21 CFR 864.6150 - Capillary blood collection tube.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Capillary blood collection tube. 864.6150 Section... blood collection tube. (a) Identification. A capillary blood collection tube is a plain or heparinized glass tube of very small diameter used to collect blood by capillary action. (b) Classification. Class I...

21 CFR 864.6150 - Capillary blood collection tube.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Capillary blood collection tube. 864.6150 Section... blood collection tube. (a) Identification. A capillary blood collection tube is a plain or heparinized glass tube of very small diameter used to collect blood by capillary action. (b) Classification. Class I...

21 CFR 864.6150 - Capillary blood collection tube.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Capillary blood collection tube. 864.6150 Section... blood collection tube. (a) Identification. A capillary blood collection tube is a plain or heparinized glass tube of very small diameter used to collect blood by capillary action. (b) Classification. Class I...

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

PubMed

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.

Enhancing separation in short-capillary electrophoresis via pressure-driven backflow.

PubMed

Tian, Miaomiao; Wang, Yujia; Mohamed, Amara Camara; Guo, Liping; Yang, Li

2015-07-01

We present a novel easy-to-operate and efficient method to improve the separation efficiency in short-capillary electrophoresis by introducing steady backflow to counterbalance electro-osmotic flow without the use of any external pressure. The backflow was easily generated by tapering the capillary end, which was achieved by heating a straight capillary and stretching it with a constant force. We investigated the net fluidic transport rate under different tip lengths and separation voltages. Good run-to-run repeatability and capillary-to-capillary reproducibility of the present method were obtained with RSD less than 1.5%, indicating the stability of the fluid transport rate in the tapered capillary, which ensures the quantification and repeatability of capillary zone electrophoresis (CZE) analysis. Enhanced separation of the tapered short capillary electrophoresis was demonstrated by CZE analyzing amino acids and positional isomers. Baseline separations were achieved in less than 60 s using a tapered capillary with the effective length of 5 cm, while no separation was achieved using a normal capillary without a tapered tip. The present study provides a promising method to use pressure-driven backflow to enhance separation efficiency in short-capillary electrophoresis, which would be of potential value in a wide application for fast analysis of complex samples. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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

NASA Astrophysics Data System (ADS)

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

2015-12-01

in heterogeneous reservoirs. Both the geologic algorithm and connectivity analysis are very fast; therefore, the integrated methodology can be used as a quick tool to estimate local capillary trapping. It can also be used as a potential complement to the full-physics simulation to evaluate safe storage capacity.

Microjet formation in a capillary by laser-induced cavitation

NASA Astrophysics Data System (ADS)

Peters, Ivo R.; Tagawa, Yoshiyuki; van der Meer, Devaraj; Prosperetti, Andrea; Sun, Chao; Lohse, Detlef

2010-11-01

A vapor bubble is created by focusing a laser pulse inside a capillary that is partially filled with water. Upon creation of the bubble, a shock wave travels through the capillary. When this shock wave meets the meniscus of the air-water interface, a thin jet is created that travels at very high speeds. A crucial ingredient for the creation of the jet is the shape of the meniscus, which is responsible for focusing the energy provided by the shock wave. We examine the formation of this jet numerically using a boundary integral method, where we prepare an initial interface at rest inside a tube with a diameter ranging from 50 to 500 μm. To simulate the effect of the bubble we then apply a short, strong pressure pulse, after which the jet forms. We investigate the influence of the shape of the meniscus, and pressure amplitude and duration on the jet formation. The jet shape and velocity obtained by the simulation compare well with experimental data, and provides good insight in the origin of the jet.

Capillary Contact Angle in a Completely Wet Groove

NASA Astrophysics Data System (ADS)

Parry, A. O.; Malijevský, A.; Rascón, C.

2014-10-01

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 θcap(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 θcap>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 θcap(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.

A microfluidic flow injection system for DNA assay with fluids driven by an on-chip integrated pump based on capillary and evaporation effects.

PubMed

Xu, Zhang-Run; Zhong, Chong-Hui; Guan, Yan-Xia; Chen, Xu-Wei; Wang, Jian-Hua; Fang, Zhao-Lun

2008-10-01

A miniaturized flow injection analysis (FIA) system integrating a micropump on a microfluidic chip based on capillary and evaporation effects was developed. The pump was made by fixing a filter paper plug with a vent tube at the channel end, it requires no peripheral equipment and provides steady flow in the microl min(-1) range for FIA operation. Valve-free sample injection was achieved at nanolitre level using an array of slotted vials. The practical applicability of the system was demonstrated by DNA assay with laser-induced fluorescence (LIF) detection. A precision of 1.6% RSD (10.0 ng microl(-1), n=15) was achieved with a sampling throughput of 76 h(-1) and sample consumption of 95 nl.

A rapid, maskless 3D prototyping for fabrication of capillary circuits: Toward urinary protein detection.

PubMed

Yan, Sheng; Zhu, Yuanqing; Tang, Shi-Yang; Li, Yuxing; Zhao, Qianbin; Yuan, Dan; Yun, Guolin; Zhang, Jun; Zhang, Shiwu; Li, Weihua

2018-04-01

Proteinuria is an established risk marker for progressive renal function loss and patients would significantly benefit from a point-of-care testing. Although extensive work has been done to develop the microfluidic devices for the detection of urinary protein, they need the complicated operation and bulky peripherals. Here, we present a rapid, maskless 3D prototyping for fabrication of capillary fluidic circuits using laser engraving. The capillary circuits can be fabricated in a short amount of time (<10 min) without the requirements of clean-room facilities and photomasks. The advanced capillary components (e.g., trigger valves, retention valves and retention bursting valves) were fabricated, enabling the sequential liquid delivery and sample-reagent mixing. With the integration of smartphone-based detection platform, the microfluidic device can quantify the urinary protein via a colorimetric analysis. By eliminating the bulky and expensive equipment, this smartphone-based detection platform is portable for on-site quantitative detection. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

[Capillary leak syndrome disclosing Ofuji's papuloerythroderma].

PubMed

Carsuzaa, F; Pierre, C; Morand, J J; Farnarier, C; Marrot, F; Kaplanski, G

1996-01-01

Capillary leak syndrome is a specific entity among syndromes with capillary hyperpermeability. Endothelial cell activation is related to the higt level of adhesion molecules (sICAM-1, sVCAM-&, sCD62E) possibly due to several cytokines (IL-2, TNF ...). An 84-year-old woman was hospitalized for erythroderma. Ofujui papuloerythroderma was diagnosed and edema was attributed to capillary leak. A kinetic study of several cytokines and adhesion molecules sCD62E, sVCAM-1 and sICAM-1 was done. Outcome was favorable with corticopuvatherapy. The capillary leak syndrome reported here is simlar to that described in other erythrodermas with or without lymphoma. The keratinocyte would be activated by the CD4 T lymphocyte via the gamma-interferon mediator. The T cell secretes cytokines (interleukin-1, tumor necrosis factor ...) which activates the endothelium and increases vascular permeability. The level of adhesion molecules and changes observed during the episode of edema demonstrated the endothelial activation.

Multistaged stokes injected Raman capillary waveguide amplifier

DOEpatents

Kurnit, Norman A.

1980-01-01

A multistaged Stokes injected Raman capillary waveguide amplifier for providing a high gain Stokes output signal. The amplifier uses a plurality of optically coupled capillary waveguide amplifiers and one or more regenerative amplifiers to increase Stokes gain to a level sufficient for power amplification. Power amplification is provided by a multifocused Raman gain cell or a large diameter capillary waveguide. An external source of CO.sub.2 laser radiation can be injected into each of the capillary waveguide amplifier stages to increase Raman gain. Devices for injecting external sources of CO.sub.2 radiation include: dichroic mirrors, prisms, gratings and Ge Brewster plates. Alternatively, the CO.sub.2 input radiation to the first stage can be coupled and amplified between successive stages.

Development of Multiple-Locus Variable-Number Tandem-Repeat Analysis for Molecular Subtyping of Campylobacter jejuni by Using Capillary Electrophoresis

PubMed Central

Techaruvichit, Punnida; Vesaratchavest, Mongkol; Keeratipibul, Suwimon; Kuda, Takashi; Kimura, Bon

2015-01-01

Campylobacter jejuni is a common cause of the frequently reported food-borne diseases in developed and developing nations. This study describes the development of multiple-locus variable-number tandem-repeat (VNTR) analysis (MLVA) using capillary electrophoresis as a novel typing method for microbial source tracking and epidemiological investigation of C. jejuni. Among 36 tandem repeat loci detected by the Tandem Repeat Finder program, 7 VNTR loci were selected and used for characterizing 60 isolates recovered from chicken meat samples from retail shops, samples from chicken meat processing factory, and stool samples. The discrimination ability of MLVA was compared with that of multilocus sequence typing (MLST). MLVA (diversity index of 0.97 with 31 MLVA types) provided slightly higher discrimination than MLST (diversity index of 0.95 with 25 MLST types). The overall concordance between MLVA and MLST was estimated at 63% by adjusted Rand coefficient. MLVA predicted MLST type better than MLST predicted MLVA type, as reflected by Wallace coefficient (Wallace coefficient for MLVA to MLST versus MLST to MLVA, 86% versus 51%). MLVA is a useful tool and can be used for effective monitoring of C. jejuni and investigation of epidemics caused by C. jejuni. PMID:26025899

Quantitative analysis of nailfold capillary morphology in patients with fibromyalgia

PubMed Central

Choi, Dug-Hyun

2015-01-01

Background/Aims Nailfold capillaroscopy (NFC) has been used to examine morphological and functional microcirculation changes in connective tissue diseases. It has been demonstrated that NFC patterns reflect abnormal microvascular dynamics, which may play a role in fibromyalgia (FM) syndrome. The aim of this study was to determine NFC patterns in FM, and their association with clinical features of FM. Methods A total of 67 patients with FM, and 30 age- and sex-matched healthy controls, were included. Nailfold capillary patterns were quantitatively analyzed using computerized NFC. The parameters of interest were as follows: number of capillaries within the central 3 mm, deletion score, apical limb width, capillary width, and capillary dimension. Capillary dimension was determined by calculating the number of capillaries using the Adobe Photoshop version 7.0. Results FM patients had a lower number of capillaries and higher deletion scores on NFC compared to healthy controls (17.3 ± 1.7 vs. 21.8 ± 2.9, p < 0.05; 2.2 ± 0.9 vs. 0.7 ± 0.6, p < 0.05, respectively). Both apical limb width (µm) and capillary width (µm) were significantly decreased in FM patients (1.1 ± 0.2 vs. 3.7 ± 0.6; 5.4 ± 0.5 vs. 7.5 ± 1.4, respectively), indicating that FM patients have abnormally decreased digital capillary diameter and density. Interestingly, there was no difference in capillary dimension between the two groups, suggesting that the length or tortuosity of capillaries in FM patients is increased to compensate for diminished microcirculation. Conclusions FM patients had altered capillary density and diameter in the digits. Diminished microcirculation on NFC may alter capillary density and increase tortuosity. PMID:26161020

Two classes of capillary optical fibers: refractive and photonic

NASA Astrophysics Data System (ADS)

Romaniuk, Ryszard S.

2008-11-01

This paper is a digest tutorial on some properties of capillary optical fibers (COF). Two basic types of capillary optical fibers are clearly distinguished. The classification is based on propagation mechanism of optical wave. The refractive, singlemode COF guides a dark hollow beam of light (DHB) with zero intensity on fiber axis. The photonic, singlemode COF carries nearly a perfect axial Gaussian beam with maximum intensity on fiber axis. A subject of the paper are these two basic kinds of capillary optical fibers of pure refractive and pure photonic mechanism of guided wave transmission. In a real capillary the wave may be transmitted by a mixed mechanism, refractive and photonic, with strong interaction of photonic and refractive guided wave modes. Refractive capillary optical fibers are used widely for photonic instrumentation applications, while photonic capillary optical fibers are considered for trunk optical communications. Replacement of classical, single mode, dispersion shifted, 1550nm optimized optical fibers for communications with photonic capillaries would potentially cause a next serious revolution in optical communications. The predictions say that such a revolution may happen within this decade. This dream is however not fulfilled yet. The paper compares guided modes in both kinds of optical fiber capillaries: refractive and photonic. The differences are emphasized indicating prospective application areas of these fibers.

Capillary CAA and perivascular Aβ-deposition: two distinct features of Alzheimer's disease pathology.

PubMed

Attems, Johannes; Yamaguchi, Haruyasu; Saido, Takaomi C; Thal, Dietmar Rudolf

2010-12-15

Cerebral amyloid angiopathy (CAA) is frequently seen in Alzheimer's disease (AD) cases and represents one of its histopathological hallmarks. CAA is characterized by amyloid β-protein (Aβ) deposits within vessel walls. In addition to arteries and veins capillaries can also be affected. Aβ deposition into the capillary wall is, thereby, known as capillary CAA (capCAA) and strongly associated with the apolipoprotein E APOEε4 allele as a risk factor. Aβ deposits along the pericapillary glia limitans are described as pericapillary Aβ (pericapAβ: synonymous with pericapillary CAA in other studies). Here, we studied the relationship between pericapAβ and capCAA in 58 human autopsy cases. Although pericapAβ and capCAA were more frequently found in AD cases compared to controls and although they exhibited a correlation to one another, detailed analysis revealed that there is a significant number of cases with pericapAβ lacking capCAA and vice versa. Moreover, single capillaries show either both pathologies or pericapAβ or capCAA only. There was no local association between these pathologies when analyzing multiple capillaries in each given case. Moreover, pericapAβ predominantly exhibited Aβ(42) whereas capCAA contained both Aβ(42) and Aβ(40). These differences as well as differences in the related astroglial reaction indicate that pericapAβ and capCAA are not directly linked. PericapAβ appears to represent initial Aβ accumulation along the glia limitans that is involved in the perivascular drainage of apoE and Aβ regardless of the APOE genotype whereas capCAA could be explained by a limited transendothelial clearance of apoE4-Aβ complexes compared to apoE2/3-Aβ complexes. Copyright © 2010 Elsevier B.V. All rights reserved.

Paramecium swimming in capillary tube

NASA Astrophysics Data System (ADS)

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.

Optothermally actuated capillary burst valve

NASA Astrophysics Data System (ADS)

Eriksen, Johan; Bilenberg, Brian; Kristensen, Anders; Marie, Rodolphe

2017-04-01

We demonstrate the optothermal actuation of individual capillary burst valves in an all-polymer microfluidic device. The capillary burst valves are realised in a planar design by introducing a fluidic constriction in a microfluidic channel of constant depth. We show that a capillary burst valve can be burst by raising the temperature due to the temperature dependence of the fluid surface tension. We address individual valves by using a local heating platform based on a thin film of near infrared absorber dye embedded in the lid used to seal the microfluidic device [L. H. Thamdrup et al., Nano Lett. 10, 826-832 (2010)]. An individual valve is burst by focusing the laser in its vicinity. We demonstrate the capture of single polystyrene 7 μm beads in the constriction triggered by the bursting of the valve.

Uniform Laser Excitation And Detection In Capillary Array Electrophoresis System And Method.

DOEpatents

Li, Qingbo; Zhou, Songsan; Liu, Changsheng

2003-10-07

A capillary electrophoresis system comprises capillaries positioned in parallel to each other forming a plane. The capillaries are configured to allow samples to migrate. A light source is configured to illuminate the capillaries and the samples therein. This causes the samples to emit light. A lens is configured to receive the light emitted by the samples and positioned directly over a first group of the capillaries and obliquely over a second group of the capillaries. The light source is further configured to illuminate the second group of capillaries more than the first group of the capillaries such that amount of light received by the lens from the first group of capillaries is substantially identical to amount of light received from the second group of capillaries when an identical amount of the samples is migrating through the first and second group capillaries.

Preparation and characterization of lysine-immobilized poly(glycidyl methacrylate) nanoparticle-coated capillary for the separation of amino acids by open tubular capillary electrochromatography.

PubMed

Xu, Liang; Cui, Pengfei; Wang, Dongmei; Tang, Cheng; Dong, Linyi; Zhang, Can; Duan, Hongquan; Yang, Victor C

2014-01-03

In this study, poly(glycidyl methacrylate) (PGMA) nanoparticles (NPs) were prepared and chemically immobilized for the first time onto a capillary inner wall for open tubular capillary electrochromatography (OTCEC). The immobilization of PGMA NPs onto the capillary was attained by a ring-opening reaction between the NPs and an amino-silylated fused capillary inner surface. Scanning electron micrographs clearly demonstrated that the NPs were bound to the capillary inner surface in a dense monolayer. The PGMA NP-coated column was then functionalized by lysine (Lys). After fuctionalization, the capillary can afford strong anodic electroosmotic flow, especially in acidic running buffers. Separations of three amino acids (including tryptophan, tyrosine and phenylalanine) were performed in NP-modified, monolayer Lys-functionalized and bare uncoated capillaries. Results indicated that the NP-coated column can provide more retention and higher resolution for analytes due to the hydrophobic interaction between analytes and the NP-coating. Run-to-run and column-to-column reproducibilities in the separation of the amino acids using the NP-modified column were also demonstrated. Copyright © 2013 Elsevier B.V. All rights reserved.

Integral criteria for large-scale multiple fingerprint solutions

NASA Astrophysics Data System (ADS)

Ushmaev, Oleg S.; Novikov, Sergey O.

2004-08-01

We propose the definition and analysis of the optimal integral similarity score criterion for large scale multmodal civil ID systems. Firstly, the general properties of score distributions for genuine and impostor matches for different systems and input devices are investigated. The empirical statistics was taken from the real biometric tests. Then we carry out the analysis of simultaneous score distributions for a number of combined biometric tests and primary for ultiple fingerprint solutions. The explicit and approximate relations for optimal integral score, which provides the least value of the FRR while the FAR is predefined, have been obtained. The results of real multiple fingerprint test show good correspondence with the theoretical results in the wide range of the False Acceptance and the False Rejection Rates.

Lower capillary density but no difference in VEGF expression in obese vs. lean young skeletal muscle in humans.

PubMed

Gavin, Timothy P; Stallings, Howard W; Zwetsloot, Kevin A; Westerkamp, Lenna M; Ryan, Nicholas A; Moore, Rebecca A; Pofahl, Walter E; Hickner, Robert C

2005-01-01

Obesity is associated with lower skeletal muscle capillarization and lower insulin sensitivity. Vascular endothelial growth factor (VEGF) is important for the maintenance of the skeletal muscle capillaries. To investigate whether VEGF and VEGF receptor [kinase insert domain-containing receptor (KDR) and Flt-1] expression are lower with obesity, vastus lateralis muscle biopsies were obtained from eight obese and eight lean young sedentary men before and 2 h after a 1-h submaximal aerobic exercise bout for the measurement of VEGF, KDR, Flt-1, and skeletal muscle fiber and capillary characteristics. There were no differences in VEGF or VEGF receptor mRNA at rest between lean and obese muscle. Exercise increased VEGF (10-fold), KDR (3-fold), and Flt-1 (5-fold) mRNA independent of group. There were no differences in VEGF, KDR, or Flt-1 protein between groups. Compared with lean skeletal muscle, the number of capillary contacts per fiber was the same, but lower capillary density (CD), greater muscle cross sectional area, and lower capillary-to-fiber area ratio were observed in both type I and II fibers in obese muscle. Multiple linear regression revealed that 49% of the variance in insulin sensitivity (homeostasis model assessment) could be explained by percentage of body fat (35%) and maximal oxygen uptake per kilogram of fat-free mass (14%). Linear regression revealed significant relationships between maximal oxygen uptake and both CD and capillary-to-fiber perimeter exchange. Although differences may exist in CD and capillary-to-fiber area ratio between lean and obese skeletal muscle, the present results provide evidence that VEGF and VEGF receptor expression are not different between lean and obese muscle.

Method and system of integrating information from multiple sources

DOEpatents

Alford, Francine A [Livermore, CA; Brinkerhoff, David L [Antioch, CA

2006-08-15

A system and method of integrating information from multiple sources in a document centric application system. A plurality of application systems are connected through an object request broker to a central repository. The information may then be posted on a webpage. An example of an implementation of the method and system is an online procurement system.

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

PubMed Central

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

2017-01-01

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

Wicking Tests for Unidirectional Fabrics: Measurements of Capillary Parameters to Evaluate Capillary Pressure in Liquid Composite Molding Processes.

PubMed

Pucci, Monica Francesca; Liotier, Pierre-Jacques; Drapier, Sylvain

2017-01-27

During impregnation of a fibrous reinforcement in liquid composite molding (LCM) processes, capillary effects have to be understood in order to identify their influence on void formation in composite parts. Wicking in a fibrous medium described by the Washburn equation was considered equivalent to a flow under the effect of capillary pressure according to the Darcy law. Experimental tests for the characterization of wicking were conducted with both carbon and flax fiber reinforcement. Quasi-unidirectional fabrics were then tested by means of a tensiometer to determine the morphological and wetting parameters along the fiber direction. The procedure was shown to be promising when the morphology of the fabric is unchanged during capillary wicking. In the case of carbon fabrics, the capillary pressure can be calculated. Flax fibers are sensitive to moisture sorption and swell in water. This phenomenon has to be taken into account to assess the wetting parameters. In order to make fibers less sensitive to water sorption, a thermal treatment was carried out on flax reinforcements. This treatment enhances fiber morphological stability and prevents swelling in water. It was shown that treated fabrics have a linear wicking trend similar to those found in carbon fabrics, allowing for the determination of capillary pressure.

Method of making tapered capillary tips with constant inner diameters

DOEpatents

Kelly, Ryan T [West Richland, WA; Page, Jason S [Kennewick, WA; Tang, Keqi [Richland, WA; Smith, Richard D [Richland, WA

2009-02-17

Methods of forming electrospray ionization emitter tips are disclosed herein. In one embodiment, an end portion of a capillary tube can be immersed into an etchant, wherein the etchant forms a concave meniscus on the outer surface of the capillary. Variable etching rates in the meniscus can cause an external taper to form. While etching the outer surface of the capillary wall, a fluid can be flowed through the interior of the capillary tube. Etching continues until the immersed portion of the capillary tube is completely etched away.

Synchronous Hepatoblastoma, Neuroblastoma, and Cutaneous Capillary Hemangiomas: A Case Report.

PubMed

Ozawa, Michael G; Cooney, Tabitha; Rangaswami, Arun; Hazard, Florette K

2016-01-01

Multiple synchronous tumors presenting in infancy raise concern for inherited or sporadic cancer predisposition syndromes, which include Beckwith-Wiedemann syndrome, familial adenomatous polyposis syndrome, and Li-Fraumeni syndrome. We report a case of a 7-month-old previously healthy male born following an in vitro fertilization-assisted twin pregnancy who presented with new-onset refractory shock, severe acidosis, and rapid decline over several hours. An autopsy revealed a ruptured liver involved by hepatoblastoma, an adrenal gland involved by neuroblastoma, and multiple cutaneous capillary hemangiomas. Standard genetic testing demonstrated that both twins were Gaucher disease (GD) carriers without evidence of other known cancer predisposition syndromes. This report describes a unique association of multiple synchronous tumors, which underscores the utility and importance of the pediatric autopsy. Moreover, given that the reported child was a GD carrier, the possibility the tumors were the result of a GD-mediated cancer-associated phenotype or an unrecognized sporadic clinical syndrome remains an unanswered, but intriguing, question worthy of further investigation.

Recent advances in capillary ultrahigh pressure liquid chromatography.

PubMed

Blue, Laura E; Franklin, Edward G; Godinho, Justin M; Grinias, James P; Grinias, Kaitlin M; Lunn, Daniel B; Moore, Stephanie M

2017-11-10

In the twenty years since its initial demonstration, capillary ultrahigh pressure liquid chromatography (UHPLC) has proven to be one of most powerful separation techniques for the analysis of complex mixtures. This review focuses on the most recent advances made since 2010 towards increasing the performance of such separations. Improvements in capillary column preparation techniques that have led to columns with unprecedented performance are described. New stationary phases and phase supports that have been reported over the past decade are detailed, with a focus on their use in capillary formats. A discussion on the instrument developments that have been required to ensure that extra-column effects do not diminish the intrinsic efficiency of these columns during analysis is also included. Finally, the impact of these capillary UHPLC topics on the field of proteomics and ways in which capillary UHPLC may continue to be applied to the separation of complex samples are addressed. Copyright © 2017 Elsevier B.V. All rights reserved.

Construction of stable capillary networks using a microfluidic device.

PubMed

Sudo, Ryo

2015-01-01

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

Capillary Rise: Validity of the Dynamic Contact Angle Models.

PubMed

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.

PubMed

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.

Capillary electrophoresis for drug analysis

NASA Astrophysics Data System (ADS)

Lurie, Ira S.

1999-02-01

Capillary electrophoresis (CE) is a high resolution separation technique which is amenable to a wide variety of solutes, including compounds which are thermally degradable, non-volatile and highly polar, and is therefore well suited for drug analysis. Techniques which have been used in our laboratory include electrokinetic chromatography (ECC), free zone electrophoresis (CZE) and capillary electrochromatography (CEC). ECC, which uses a charged run buffer additive which migrates counter to osmotic flow, is excellent for many applications, including, drug screening and analyses of heroin, cocaine and methamphetamine samples. ECC approaches include the use of micelles and charged cyclodextrins, which allow for the separation of complex mixtures. Simultaneous separation of acidic, neutral and basic solutes and the resolution of optical isomers and positional isomers are possible. CZE has been used for the analysis of small ions (cations and anions) in heroin exhibits. For the ECC and CZE experiments performed in our laboratory, uncoated capillaries were used. In contrast, CEC uses capillaries packed with high performance liquid chromatography stationary phases, and offers both high peak capacities and unique selectivities. Applications include the analysis of cannabinoids and drug screening. Although CE suffers from limited concentration sensitivity, it is still applicable to trace analysis of drug samples, especially when using injection techniques such as stacking, or detection schemes such as laser induced fluorescence and extended pathlength UV.

Multianalyte detection using a capillary-based flow immunosensor.

PubMed

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.

Characteristics of a capillary-discharge flash x-ray generator

NASA Astrophysics Data System (ADS)

Sato, Eiichi; Hayasi, Yasuomi; Usuki, Tatsumi; Sato, Koetsu; Takayama, Kazuyoshi; Ido, Hideaki

2002-11-01

The fundamental experiments for measuring soft x-ray characteristics from the vacuum capillary are described. These experiments are primarily performed in order to generate line spectra such as x-ray lasers. The generator consists of a high-voltage power supply, a polarity-inversion ignitron pulse generator, a turbo-molecular pump, and a radiation tube with a capillary. A high-voltage condenser of 0.2 μF in the pulse generator is charged up to 20 kV by the power supply, and the electric charges in the condenser are discharged to the capillary in the tube after closing the ignitron. During the discharge, weakly ionized plasma forms on the inner and outer sides of a capillary. In the present work, the pump evacuates air from the tube with a pressure of about 1 mPa, and a demountable capillary was developed in order to measure x-ray spectra according to changes in the capillary length. In this capillary, the anode (target) and cathode elements can be changed corresponding to the objectives. The capillary diameter is 2.0 mm, and the length is adjusted from 1 to 50 mm. When a capillary with aluminum anode and cathode electrodes was employed, both the cathode voltage and the discharge current almost displayed damp oscillations. The peak values of the voltage and current increased when the charging voltage was increased and their maximum values were -10.8 kV and 4.7 kV, respectively. The x-ray durations observed by a 1.6 μm aluminum filter were less than 30 μs, and we detected the aluminum characteristic x-ray intensity using a 6.8 μm aluminum filter. In the spectrum measurement, two sets of aluminum and titanium electrodes were employed, and we observed multi-line spectra. The line photon energies seldom varied according to changes in teh condenser charging voltage and to changes in the electrode element. In the case where the titanium electrode was employed, the line number decreased with corresponding decreases in the capillary length. Compared with incoherent

Weight-controlled capillary viscometer

NASA Astrophysics Data System (ADS)

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.

Cerebral capillary velocimetry based on temporal OCT speckle contrast.

PubMed

Choi, Woo June; Li, Yuandong; Qin, Wan; Wang, Ruikang K

2016-12-01

We propose a new optical coherence tomography (OCT) based method to measure red blood cell (RBC) velocities of single capillaries in the cortex of rodent brain. This OCT capillary velocimetry exploits quantitative laser speckle contrast analysis to estimate speckle decorrelation rate from the measured temporal OCT speckle signals, which is related to microcirculatory flow velocity. We hypothesize that OCT signal due to sub-surface capillary flow can be treated as the speckle signal in the single scattering regime and thus its time scale of speckle fluctuations can be subjected to single scattering laser speckle contrast analysis to derive characteristic decorrelation time. To validate this hypothesis, OCT measurements are conducted on a single capillary flow phantom operating at preset velocities, in which M-mode B-frames are acquired using a high-speed OCT system. Analysis is then performed on the time-varying OCT signals extracted at the capillary flow, exhibiting a typical inverse relationship between the estimated decorrelation time and absolute RBC velocity, which is then used to deduce the capillary velocities. We apply the method to in vivo measurements of mouse brain, demonstrating that the proposed approach provides additional useful information in the quantitative assessment of capillary hemodynamics, complementary to that of OCT angiography.

Capillary electrophoresis: principles and applications in illicit drug analysis.

PubMed

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 Flows Along Open Channel Conduits: The Open-Star Section

NASA Technical Reports Server (NTRS)

Weislogel, Mark; Geile, John; Chen, Yongkang; Nguyen, Thanh Tung; Callahan, Michael

2014-01-01

Capillary rise in tubes, channels, and grooves has received significant attention in the literature for over 100 years. In yet another incremental extension of such work, a transient capillary rise problem is solved for spontaneous flow along an interconnected array of open channels forming what is referred to as an 'open-star' section. This geometry possesses several attractive characteristics including passive phase separations and high diffusive gas transport. Despite the complex geometry, novel and convenient approximations for capillary pressure and viscous resistance enable closed form predictions of the flow. As part of the solution, a combined scaling approach is applied that identifies unsteady-inertial-capillary, convective-inertial-capillary, and visco-capillary transient regimes in a single parameter. Drop tower experiments are performed employing 3-D printed conduits to corroborate all findings.

Treelike networks accelerating capillary flow.

PubMed

Shou, Dahua; Ye, Lin; Fan, Jintu

2014-05-01

Transport in treelike networks has received wide attention in natural systems, oil recovery, microelectronic cooling systems, and textiles. Existing studies are focused on transport behaviors under a constant potential difference (including pressure, temperature, and voltage) in a steady state [B. Yu and B. Li, Phys. Rev. E 73, 066302 (2006); J. Chen, B. Yu, P. Xu, and Y. Li, Phys. Rev. E 75, 056301 (2007)]. However, dynamic (time-dependent) transport in such systems has rarely been concerned. In this work, we theoretically investigate the dynamics of capillary flow in treelike networks and design the distribution of radius and length of local branches for the fastest capillary flow. It is demonstrated that capillary flow in the optimized tree networks is faster than in traditional parallel tube nets under fixed constraints. As well, the flow time of the liquid is found to increase approximately linearly with penetration distance, which differs from Washburn's classic description that flow time increases as the square of penetration distance in a uniform tube.

Micromechanism linear actuator with capillary force sealing

DOEpatents

Sniegowski, Jeffry J.

1997-01-01

A class of micromachine linear actuators whose function is based on gas driven pistons in which capillary forces are used to seal the gas behind the piston. The capillary forces also increase the amount of force transmitted from the gas pressure to the piston. In a major subclass of such devices, the gas bubble is produced by thermal vaporization of a working fluid. Because of their dependence on capillary forces for sealing, such devices are only practical on the sub-mm size scale, but in that regime they produce very large force times distance (total work) values.

High-throughput biological small-angle X-ray scattering with a robotically loaded capillary cell

PubMed Central

Nielsen, S. S.; Møller, M.; Gillilan, R. E.

2012-01-01

With the rise in popularity of biological small-angle X-ray scattering (BioSAXS) measurements, synchrotron beamlines are confronted with an ever-increasing number of samples from a wide range of solution conditions. To meet these demands, an increasing number of beamlines worldwide have begun to provide automated liquid-handling systems for sample loading. This article presents an automated sample-loading system for BioSAXS beamlines, which combines single-channel disposable-tip pipetting with a vacuum-enclosed temperature-controlled capillary flow cell. The design incorporates an easily changeable capillary to reduce the incidence of X-ray window fouling and cross contamination. Both the robot-control and the data-processing systems are written in Python. The data-processing code, RAW, has been enhanced with several new features to form a user-friendly BioSAXS pipeline for the robot. The flow cell also supports efficient manual loading and sample recovery. An effective rinse protocol for the sample cell is developed and tested. Fluid dynamics within the sample capillary reveals a vortex ring pattern of circulation that redistributes radiation-damaged material. Radiation damage is most severe in the boundary layer near the capillary surface. At typical flow speeds, capillaries below 2 mm in diameter are beginning to enter the Stokes (creeping flow) regime in which mixing due to oscillation is limited. Analysis within this regime shows that single-pass exposure and multiple-pass exposure of a sample plug are functionally the same with regard to exposed volume when plug motion reversal is slow. The robot was tested on three different beamlines at the Cornell High-Energy Synchrotron Source, with a variety of detectors and beam characteristics, and it has been used successfully in several published studies as well as in two introductory short courses on basic BioSAXS methods. PMID:22509071

Synthetic Capillaries to Control Microscopic Blood Flow

NASA Astrophysics Data System (ADS)

Sarveswaran, K.; Kurz, V.; Dong, Z.; Tanaka, T.; Penny, S.; Timp, G.

2016-02-01

Capillaries pervade human physiology. The mean intercapillary distance is only about 100 μm in human tissue, which indicates the extent of nutrient diffusion. In engineered tissue the lack of capillaries, along with the associated perfusion, is problematic because it leads to hypoxic stress and necrosis. However, a capillary is not easy to engineer due to its complex cytoarchitecture. Here, it is shown that it is possible to create in vitro, in about 30 min, a tubular microenvironment with an elastic modulus and porosity consistent with human tissue that functionally mimicks a bona fide capillary using “live cell lithography”(LCL) to control the type and position of cells on a composite hydrogel scaffold. Furthermore, it is established that these constructs support the forces associated with blood flow, and produce nutrient gradients similar to those measured in vivo. With LCL, capillaries can be constructed with single cell precision—no other method for tissue engineering offers such precision. Since the time required for assembly scales with the number of cells, this method is likely to be adapted first to create minimal functional units of human tissue that constitute organs, consisting of a heterogeneous population of 100-1000 cells, organized hierarchically to express a predictable function.

Synthetic Capillaries to Control Microscopic Blood Flow.

PubMed

Sarveswaran, K; Kurz, V; Dong, Z; Tanaka, T; Penny, S; Timp, G

2016-02-24

Capillaries pervade human physiology. The mean intercapillary distance is only about 100 μm in human tissue, which indicates the extent of nutrient diffusion. In engineered tissue the lack of capillaries, along with the associated perfusion, is problematic because it leads to hypoxic stress and necrosis. However, a capillary is not easy to engineer due to its complex cytoarchitecture. Here, it is shown that it is possible to create in vitro, in about 30 min, a tubular microenvironment with an elastic modulus and porosity consistent with human tissue that functionally mimicks a bona fide capillary using "live cell lithography"(LCL) to control the type and position of cells on a composite hydrogel scaffold. Furthermore, it is established that these constructs support the forces associated with blood flow, and produce nutrient gradients similar to those measured in vivo. With LCL, capillaries can be constructed with single cell precision-no other method for tissue engineering offers such precision. Since the time required for assembly scales with the number of cells, this method is likely to be adapted first to create minimal functional units of human tissue that constitute organs, consisting of a heterogeneous population of 100-1000 cells, organized hierarchically to express a predictable function.

Engineering anastomosis between living capillary networks and endothelial cell-lined microfluidic channels.

PubMed

Wang, Xiaolin; Phan, Duc T T; Sobrino, Agua; George, Steven C; Hughes, Christopher C W; Lee, Abraham P

2016-01-21

This paper reports a method for generating an intact and perfusable microvascular network that connects to microfluidic channels without appreciable leakage. This platform incorporates different stages of vascular development including vasculogenesis, endothelial cell (EC) lining, sprouting angiogenesis, and anastomosis in sequential order. After formation of a capillary network inside the tissue chamber via vasculogenesis, the adjacent microfluidic channels are lined with a monolayer of ECs, which then serve as the high-pressure input ("artery") and low pressure output ("vein") conduits. To promote a tight interconnection between the artery/vein and the capillary network, sprouting angiogenesis is induced, which promotes anastomosis of the vasculature inside the tissue chamber with the EC lining along the microfluidic channels. Flow of fluorescent microparticles confirms the perfusability of the lumenized microvascular network, and minimal leakage of 70 kDa FITC-dextran confirms physiologic tightness of the EC junctions and completeness of the interconnections between artery/vein and the capillary network. This versatile device design and its robust construction methodology establish a physiological transport model of interconnected perfused vessels from artery to vascularized tissue to vein. The system has utility in a wide range of organ-on-a-chip applications as it enables the physiological vascular interconnection of multiple on-chip tissue constructs that can serve as disease models for drug screening.

A prototype heat pipe heat exchanger for the capillary pumped loop flight experiment

NASA Technical Reports Server (NTRS)

Ku, Jentung; Yun, Seokgeun; Kroliczek, Edward J.

1992-01-01

A Capillary Pumped Two-Phase Heat Transport Loop (CAPL) Flight Experiment, currently planned for 1993, will provide microgravity verification of the prototype capillary pumped loop (CPL) thermal control system for EOS. CAPL employs a heat pipe heat exchanger (HPHX) to couple the condenser section of the CPL to the radiator assembly. A prototype HPHX consisting of a heat exchanger (HX), a header heat pipe (HHP), a spreader heat pipe (SHP), and a flow regulator has been designed and tested. The HX transmits heat from the CPL condenser to the HHP, while the HHP and SHP transport heat to the radiator assembly. The flow regulator controls flow distribution among multiple parallel HPHX's. Test results indicated that the prototype HPHX could transport up to 800 watts with an overall heat transfer coefficient of more than 6000 watts/sq m-deg C. Flow regulation among parallel HPHX's was also demonstrated.

Curriculum Integration in Arts Education: Connecting Multiple Art Forms through the Idea of "Space"

ERIC Educational Resources Information Center

Bautista, Alfredo; Tan, Liang See; Ponnusamy, Letchmi Devi; Yau, Xenia

2016-01-01

Arts integration research has focused on documenting how the teaching of specific art forms can be integrated with "core" academic subject matters (e.g. science, mathematics and literacy). However, the question of how the teaching of multiple art forms themselves can be integrated in schools remains to be explored by educational…

Anisotropic capillary barrier for waste site surface covers

DOEpatents

Stormont, J.C.

1996-08-27

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

Anisotropic capillary barrier for waste site surface covers

DOEpatents

Stormont, John C.

1996-01-01

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

Empathetic, Critical Integrations of Multiple Perspectives: A Core Practice for Language Teacher Education?

ERIC Educational Resources Information Center

Daniel, Shannon M.

2015-01-01

In this self-study, the author reflects on her implementation of empathetic, critical integrations of multiple perspectives (ECI), which she designed to afford preservice teachers the opportunity to discuss and collectively reflect upon the oft-diverging multiple perspectives, values, and practices they experience during their practicum (Daniel,…

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

NASA Astrophysics Data System (ADS)

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.

Displaced capillary dies

DOEpatents

Kalejs, Juris P.; Chalmers, Bruce; Surek, Thomas

1982-01-01

An asymmetrical shaped capillary die made exclusively of graphite is used to grow silicon ribbon which is capable of being made into solar cells that are more efficient than cells produced from ribbon made using a symmetrically shaped die.

Displaced capillary dies

DOEpatents

Kalejs, Juris P.; Chalmers, Bruce; Surek, Thomas

1984-01-01

An asymmetrical shaped capillary die made exclusively of graphite is used to grow silicon ribbon which is capable of being made into solar cells that are more efficient than cells produced from ribbon made using a symmetrically shaped die.

Shared mental models of integrated care: aligning multiple stakeholder perspectives.

PubMed

Evans, Jenna M; Baker, G Ross

2012-01-01

Health service organizations and professionals are under increasing pressure to work together to deliver integrated patient care. A common understanding of integration strategies may facilitate the delivery of integrated care across inter-organizational and inter-professional boundaries. This paper aims to build a framework for exploring and potentially aligning multiple stakeholder perspectives of systems integration. The authors draw from the literature on shared mental models, strategic management and change, framing, stakeholder management, and systems theory to develop a new construct, Mental Models of Integrated Care (MMIC), which consists of three types of mental models, i.e. integration-task, system-role, and integration-belief. The MMIC construct encompasses many of the known barriers and enablers to integrating care while also providing a comprehensive, theory-based framework of psychological factors that may influence inter-organizational and inter-professional relations. While the existing literature on integration focuses on optimizing structures and processes, the MMIC construct emphasizes the convergence and divergence of stakeholders' knowledge and beliefs, and how these underlying cognitions influence interactions (or lack thereof) across the continuum of care. MMIC may help to: explain what differentiates effective from ineffective integration initiatives; determine system readiness to integrate; diagnose integration problems; and develop interventions for enhancing integrative processes and ultimately the delivery of integrated care. Global interest and ongoing challenges in integrating care underline the need for research on the mental models that characterize the behaviors of actors within health systems; the proposed framework offers a starting point for applying a cognitive perspective to health systems integration.

Application of CHESS single-bounce capillaries at synchrotron beamlines

NASA Astrophysics Data System (ADS)

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.

Mapping human brain capillary water lifetime: high‐resolution metabolic neuroimaging

PubMed Central

Li, Xin; Sammi, Manoj K.; Bourdette, Dennis N.; Neuwelt, Edward A.

2015-01-01

Shutter‐speed analysis of dynamic‐contrast‐agent (CA)‐enhanced normal, multiple sclerosis (MS), and glioblastoma (GBM) human brain data gives the mean capillary water molecule lifetime (τ b) and blood volume fraction (v b; capillary density–volume product (ρ † V)) in a high‐resolution 1H2O MRI voxel (40 μL) or ROI. The equilibrium water extravasation rate constant, k po (τ b −1), averages 3.2 and 2.9 s−1 in resting‐state normal white matter (NWM) and gray matter (NGM), respectively (n = 6). The results (italicized) lead to three major conclusions. (A) k po differences are dominated by capillary water permeability (P W †), not size, differences. NWM and NGM voxel k po and vb values are independent. Quantitative analyses of concomitant population‐averaged k po, vb variations in normal and normal‐appearing MS brain ROIs confirm PW † dominance. (B) P W † is dominated (>95%) by a trans(endothelial)cellular pathway, not the P CA † paracellular route. In MS lesions and GBM tumors, PCA † increases but PW † decreases. (C) k po tracks steady‐state ATP production/consumption flux per capillary. In normal, MS, and GBM brain, regional k po correlates with literature MRSI ATP (positively) and Na + (negatively) tissue concentrations. This suggests that the PW † pathway is metabolically active. Excellent agreement of the relative NGM/NWM k po vb product ratio with the literature 31PMRSI‐MT CMRoxphos ratio confirms the flux property. We have previously shown that the cellular water molecule efflux rate constant (k io) is proportional to plasma membrane P‐type ATPase turnover, likely due to active trans‐membrane water cycling. With synaptic proximities and synergistic metabolic cooperativities, polar brain endothelial, neuroglial, and neuronal cells form “gliovascular units.” We hypothesize that a chain of water cycling processes transmits brain metabolic activity to k po, letting it report neurogliovascular unit Na

Numerical analysis of cell adhesion in capillary flow

NASA Astrophysics Data System (ADS)

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

2016-11-01

Numerical simulation of cell adhesion was performed for capillaries whose diameter is comparable to or smaller than that of the cell. Despite a lot of works about leukocyte and tumor cell rolling, cell motion in capillaries has remained unclear. 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 is obtained for various values of capillary diameter and receptor density. According to our numerical results, 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 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. This research was supported by JSPS KAKENHI Grant Numbers 25000008, 26107703, 14J03967. We also acknowledge support from the Tohoku University Division for International Advanced Research and Education Organization.

Assessing vitamin D nutritional status: Is capillary blood adequate?

PubMed

Jensen, M E; Ducharme, F M; Théorêt, Y; Bélanger, A-S; Delvin, E

2016-06-01

Venous blood is the usual sample for measuring various biomarkers, including 25-hydroxyvitamin D (25OHD). However, it can prove challenging in infants and young children. Hence the finger-prick capillary collection is an alternative, being a relatively simple procedure perceived to be less invasive. We elected to validate the use of capillary blood sampling for 25OHD quantification by liquid chromatography tandem-mass spectrometry (LC/MS-MS). Venous and capillary blood samples were simultaneously collected from 15 preschool-aged children with asthma 10days after receiving 100,000IU of vitamin-D3 or placebo and 20 apparently healthy adult volunteers. 25OHD was measured by an in-house LC/MS-MS method. The venous 25OHD values varied between 23 and 255nmol/l. The venous and capillary blood total 25OHD concentrations highly correlated (r(2)=0.9963). The mean difference (bias) of capillary blood 25OHD compared to venous blood was 2.0 (95% CI: -7.5, 11.5) nmol/l. Our study demonstrates excellent agreement with no evidence of a clinically important bias between venous and capillary serum 25OHD concentrations measured by LC/MS-MS over a wide range of values. Under those conditions, capillary blood is therefore adequate for the measurement of 25OHD. Copyright © 2016 Elsevier B.V. All rights reserved.

Automated enzyme-based diagonal capillary electrophoresis: application to phosphopeptide characterization

PubMed Central

Wojcik, Roza; Vannatta, Michael

2010-01-01

Diagonal capillary electrophoresis is a form of two-dimensional capillary electrophoresis that employs identical separation modes in each dimension. The distal end of the first capillary incorporates an enzyme-based microreactor. Analytes that are not modified by the reactor will have identical migration times in the two capillaries and will generate spots that fall on the diagonal in a reconstructed two-dimensional electropherogram. Analytes that undergo enzymatic modification in the reactor will have a different migration time in the second capillary and will generate spots that fall off the diagonal in the electropherogram. We demonstrate the system with immobilized alkaline phosphatase to monitor the phosphorylation status of a mixture of peptides. This enzyme-based diagonal capillary electrophoresis assay appears to be generalizable; any post-translational modification can be detected as long as an immobilized enzyme is available that reacts with the modification under electrophoretic conditions. PMID:20099889

Quantitative fine structure of capillaries in subregions of the rat subfornical organ.

PubMed

Shaver, S W; Sposito, N M; Gross, P M

1990-04-01

The differentiated cytology across subregions of the rat subfornical organ (SFO) prompted our hypothesis that ultrastructural features of capillary endothelial cells would vary topographically and quantitatively within this small nucleus. We used electron microscopic and computer-based morphometric methods to assess fine structural dimensions of the capillary endothelium in four distinct subregions of the SFO from Long-Evans and homozygous Brattleboro rats. Three types of capillary were present. Type III capillaries (resembling those of endocrine glands) had an average wall thickness of 0.17 microns, 54% thinner than those of Type I and II capillaries. Pericapillary spaces around Type III capillaries measured 56 microns2, 100% larger than for Type I vessels (resembling those of skeletal muscle). Only Type III capillaries contained fenestrations (9 per microns2 of endothelial cell) and were the predominant type of capillary in central and caudal subregions of the SFO. Type I capillaries, prevalent in the transitional subregion between the central and rostral parts of the SFO, had 10 cytoplasmic vesicles per micron2 of endothelial cell area, a number not different from that of Type III capillaries but 3x the frequency found in Type II vessels. Type II capillaries (those typical of "blood-brain barrier" endothelium) had low vesicular density (3 per microns2), no fenestrations, and no pericapillary spaces. Luminal diameters and the densities of mitochondria and intercellular junctions were not different among capillary types or subregions in the SFO. Furthermore, there were no morphometric differences for any capillary dimensions between Long-Evans and Brattleboro rats.(ABSTRACT TRUNCATED AT 250 WORDS)

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

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

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

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

Analytical approximations for effective relative permeability in the capillary limit

NASA Astrophysics Data System (ADS)

Rabinovich, Avinoam; Li, Boxiao; Durlofsky, Louis J.

2016-10-01

We present an analytical method for calculating two-phase effective relative permeability, krjeff, where j designates phase (here CO2 and water), under steady state and capillary-limit assumptions. These effective relative permeabilities may be applied in experimental settings and for upscaling in the context of numerical flow simulations, e.g., for CO2 storage. An exact solution for effective absolute permeability, keff, in two-dimensional log-normally distributed isotropic permeability (k) fields is the geometric mean. We show that this does not hold for krjeff since log normality is not maintained in the capillary-limit phase permeability field (Kj=k·krj) when capillary pressure, and thus the saturation field, is varied. Nevertheless, the geometric mean is still shown to be suitable for approximating krjeff when the variance of ln⁡k is low. For high-variance cases, we apply a correction to the geometric average gas effective relative permeability using a Winsorized mean, which neglects large and small Kj values symmetrically. The analytical method is extended to anisotropically correlated log-normal permeability fields using power law averaging. In these cases, the Winsorized mean treatment is applied to the gas curves for cases described by negative power law exponents (flow across incomplete layers). The accuracy of our analytical expressions for krjeff is demonstrated through extensive numerical tests, using low-variance and high-variance permeability realizations with a range of correlation structures. We also present integral expressions for geometric-mean and power law average krjeff for the systems considered, which enable derivation of closed-form series solutions for krjeff without generating permeability realizations.

Novel gas chromatographic detector utilizing the localized surface plasmon resonance of a gold nanoparticle monolayer inside a glass capillary.

PubMed

Chen, Fong-Yi; Chang, Wei-Cheng; Jian, Rih-Sheng; Lu, Chia-Jung

2014-06-03

This paper presents the design, assembly, and evaluation of a novel gas chromatographic detector intended to measure the absorbance of the localized surface plasmon resonance (LSPR) of a gold nanoparticle monolayer in response to eluted samples from a capillary column. Gold nanoparticles were chemically immobilized on the inner wall of a glass capillary (i.d. 0.8 mm, length = 5-15 cm). The eluted samples flowed through the glass capillary and were adsorbed onto a gold nanoparticle surface, which resulted in changes in the LSPR absorbance. The LSPR probing light source used a green light-emitting diode (LED; λ(center) = 520 nm), and the light traveled through the glass wall of the capillary with multiple total reflections. The changes in the light intensity were measured by a photodiode at the rear of the glass capillary. The sensitivity of this detector can be improved by using a longer spiral glass capillary. The detector is more sensitive when operated at a lower temperature and at a slower carrier velocity. The calibration lines of 8 preliminary test compounds were all linear (R(2) > 0.99). The detection limits (3σ) ranged from 22 ng (n-butanol) to 174 ng (2-pentanone) depending on the volatility of the chemicals and the affinity to the citrate lignads attached to the gold nanoparticle surface. This detector consumed a very low amount of energy and could be operated with an air carrier gas, which makes this detector a promising option for portable GC or μGC.

Efficient algorithms for fast integration on large data sets from multiple sources.

PubMed

Mi, Tian; Rajasekaran, Sanguthevar; Aseltine, Robert

2012-06-28

Recent large scale deployments of health information technology have created opportunities for the integration of patient medical records with disparate public health, human service, and educational databases to provide comprehensive information related to health and development. Data integration techniques, which identify records belonging to the same individual that reside in multiple data sets, are essential to these efforts. Several algorithms have been proposed in the literatures that are adept in integrating records from two different datasets. Our algorithms are aimed at integrating multiple (in particular more than two) datasets efficiently. Hierarchical clustering based solutions are used to integrate multiple (in particular more than two) datasets. Edit distance is used as the basic distance calculation, while distance calculation of common input errors is also studied. Several techniques have been applied to improve the algorithms in terms of both time and space: 1) Partial Construction of the Dendrogram (PCD) that ignores the level above the threshold; 2) Ignoring the Dendrogram Structure (IDS); 3) Faster Computation of the Edit Distance (FCED) that predicts the distance with the threshold by upper bounds on edit distance; and 4) A pre-processing blocking phase that limits dynamic computation within each block. We have experimentally validated our algorithms on large simulated as well as real data. Accuracy and completeness are defined stringently to show the performance of our algorithms. In addition, we employ a four-category analysis. Comparison with FEBRL shows the robustness of our approach. In the experiments we conducted, the accuracy we observed exceeded 90% for the simulated data in most cases. 97.7% and 98.1% accuracy were achieved for the constant and proportional threshold, respectively, in a real dataset of 1,083,878 records.

Paper Capillary Enables Effective Sampling for Microfluidic Paper Analytical Devices.

PubMed

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.

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

PubMed

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

2018-01-12

The popularity of novel nanoparticles coated capillary column has aroused widespread attention of researchers. Metal organic frameworks (MOFs) with special structure and chemical properties have received great interest in separation sciences. This work presents the investigation of HKUST-1 (Hong Kong University of Science and Technology-1, called Cu 3 (BTC) 2 or MOF-199) nanoparticles as a new type of coating material for capillary electrochromatography. For the first time, three layers coating (3-LC), five layers coating (5-LC), ten layers coating (10-LC), fifteen layers coating (15-LC), twenty layers coating(20-LC) and twenty-five layers coating (25-LC) capillary columns coated with HKUST-1 nanoparticles were synthesized by covalent bond with in situ, layer-by-layer self-assembly approach. The results of scanning electron microscopy (SEM), X-ray diffraction (XRD) and plasma atomic emission spectrometry (ICP-AES) indicated that HKUST-1 was successfully grafted on the inner wall of the capillary. The separating performances of 3-LC, 5-LC, 10-LC, 15-LC, 20-LC and 25-LC open tubular (OT) capillary columns were studied with some neutral small organic molecules. The results indicated that the neutral small organic molecules were separated successfully with 10-LC, 15-LC and 20-LC OT capillary columns because of the size selectivity of lattice aperture and hydrophobicity of organic ligands. In addition, 10-LC and 15-LC OT capillary columns showed better performance for the separation of certain phenolic compounds. Furthermore, 10-LC, 15-LC and 20-LC OT capillary columns exhibited good intra-day repeatability with the relative standard deviations (RSDs; %) of migration time and peak areas lying in the range of 0.3-1.2% and 0.5-4.2%, respectively. For inter-day reproducibility, the RSDs of the three OT capillary columns were found to be lying in the range of 0.3-5.5% and 0.3-4.5% for migration time and peak area, respectively. The RSDs of retention times for column

Exact Solution for Capillary Bridges Properties by Shooting Method

NASA Astrophysics Data System (ADS)

Qiang-Nian, Li; Jia-Qi, Zhang; Feng-Xi, Zhou

2017-04-01

The investigation of liquid bridge force acting between wet particles has great significance in many fields. In this article, the exact solution of capillary force between two unequal-sized spherical particles is investigated. Firstly, The Young-Laplace equation with moving boundary is converted into a set of ordinary differential equations with two fix point boundary using variable substitution technique, in which the gravity effects have been neglected. The geometry of the liquid bridge between two particles is solved by shooting method. After that, the gorge method is applied to calculate the capillary-bridge force that is consists of contributions from the capillary suction and surface tension. Finally, the effect of various parameters including distance between two spheres, radii of spheres, and contact angles on the capillary force are investigated. It is shown that the presented approach is an efficient and accurate algorithm for capillary force between two particles in complex situations.

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

PubMed

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.

Recent advances of ionic liquids and polymeric ionic liquids in capillary electrophoresis and capillary electrochromatography.

PubMed

Tang, Sheng; Liu, Shujuan; Guo, Yong; Liu, Xia; Jiang, Shengxiang

2014-08-29

Ionic liquids (ILs) and polymeric ionic liquids (PILs) with unique and fascinating properties have drawn considerable interest for their use in separation science, especially in chromatographic techniques. In this article, significant contributions of ILs and PILs in the improvement of capillary electrophoresis and capillary electrochromatography are described, and a specific overview of the most relevant examples of their applications in the last five years is also given. Accordingly, some general conclusions and future perspectives in these areas are discussed. Copyright © 2014 Elsevier B.V. All rights reserved.

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

NASA Astrophysics Data System (ADS)

Kojima, Takao M.

2018-02-01

When keV energy ions are injected into a tilted insulating capillary, a certain fraction of the injected ions are transported through the tilt angle of the capillary. This ion guiding phenomenon is considered to be caused by a self-organizing charge distribution, where the inner wall of the capillary becomes charged by initial incoming ions. The charge distribution, which is formed, can guide following ions toward the exit of the capillary. Since the initial discovery of this effect, studies of ion guiding by insulating capillaries have been extended to various materials, and different sizes and shapes of capillaries. In recent years, some investigations of the guiding effect of macro-size curved capillaries have also been reported. In this review, relevant studies in a history of ion guiding in curved capillaries are discussed and future directions in this field are considered.

Nature-Inspired Capillary-Driven Welding Process for Boosting Metal-Oxide Nanofiber Electronics.

PubMed

Meng, You; Lou, Kaihua; Qi, Rui; Guo, Zidong; Shin, Byoungchul; Liu, Guoxia; Shan, Fukai

2018-06-20

Recently, semiconducting nanofiber networks (NFNs) have been considered as one of the most promising platforms for large-area and low-cost electronics applications. However, the high contact resistance among stacking nanofibers remained to be a major challenge, leading to poor device performance and parasitic energy consumption. In this report, a controllable welding technique for NFNs was successfully demonstrated via a bioinspired capillary-driven process. The interfiber connections were well-achieved via a cooperative concept, combining localized capillary condensation and curvature-induced surface diffusion. With the improvements of the interfiber connections, the welded NFNs exhibited enhanced mechanical property and high electrical performance. The field-effect transistors (FETs) based on the welded Hf-doped In 2 O 3 (InHfO) NFNs were demonstrated for the first time. Meanwhile, the mechanisms involved in the grain-boundary modulation for polycrystalline metal-oxide nanofibers were discussed. When the high-k ZrO x dielectric thin films were integrated into the FETs, the field-effect mobility and operating voltage were further improved to be 25 cm 2 V -1 s -1 and 3 V, respectively. This is one of the best device performances among the reported nanofibers-based FETs. These results demonstrated the potencies of the capillary-driven welding process and grain-boundary modulation mechanism for metal-oxide NFNs, which could be applicable for high-performance, large-scale, and low-power functional electronics.

Viscous peeling with capillary suction

NASA Astrophysics Data System (ADS)

Peng, Gunnar; Lister, John

2014-11-01

If an elastic tape is stuck to a rigid substrate by a thin film of viscous fluid and then peeled off by pulling at a small angle to the horizontal, then both viscous and capillary forces affect the peeling speed (McEwan and Taylor, 1966). If there is no capillary meniscus (e.g. if the peeling is due to viscous fluid being injected under the tape), then the peeling speed is given by a Cox-Voinov-like law, and is an increasing function of the peeling angle. We show that, with a meniscus present, the effect of the capillary forces is to suck down the tape, reducing the effective peeling angle and hence the peeling speed. When surface tension dominates and the peeling speed tends to zero, the system transitions to a new state whose time-evolution can be described by a system of coupled ordinary differential equations. These asymptotic results are confirmed by numerical calculations. Similar results hold for the peeling-by-bending of elastic beams, with ``angle'' replaced by ``curvature'' (i.e. bending moment).

Quadrature rules with multiple nodes for evaluating integrals with strong singularities

NASA Astrophysics Data System (ADS)

Milovanovic, Gradimir V.; Spalevic, Miodrag M.

2006-05-01

We present a method based on the Chakalov-Popoviciu quadrature formula of Lobatto type, a rather general case of quadrature with multiple nodes, for approximating integrals defined by Cauchy principal values or by Hadamard finite parts. As a starting point we use the results obtained by L. Gori and E. Santi (cf. On the evaluation of Hilbert transforms by means of a particular class of Turan quadrature rules, Numer. Algorithms 10 (1995), 27-39; Quadrature rules based on s-orthogonal polynomials for evaluating integrals with strong singularities, Oberwolfach Proceedings: Applications and Computation of Orthogonal Polynomials, ISNM 131, Birkhauser, Basel, 1999, pp. 109-119). We generalize their results by using some of our numerical procedures for stable calculation of the quadrature formula with multiple nodes of Gaussian type and proposed methods for estimating the remainder term in such type of quadrature formulae. Numerical examples, illustrations and comparisons are also shown.

Capillary Driven Flows Along Differentially Wetted Interior Corners

NASA Technical Reports Server (NTRS)

Golliher, Eric L. (Technical Monitor); Nardin, C. L.; Weislogel, M. M.

2005-01-01

Closed-form analytic solutions useful for the design of capillary flows in a variety of containers possessing interior corners were recently collected and reviewed. Low-g drop tower and aircraft experiments performed at NASA to date show excellent agreement between theory and experiment for perfectly wetting fluids. The analytical expressions are general in terms of contact angle, but do not account for variations in contact angle between the various surfaces within the system. Such conditions may be desirable for capillary containment or to compute the behavior of capillary corner flows in containers consisting of different materials with widely varying wetting characteristics. A simple coordinate rotation is employed to recast the governing system of equations for flows in containers with interior corners with differing contact angles on the faces of the corner. The result is that a large number of capillary driven corner flows may be predicted with only slightly modified geometric functions dependent on corner angle and the two (or more) contact angles of the system. A numerical solution is employed to verify the new problem formulation. The benchmarked computations support the use of the existing theoretical approach to geometries with variable wettability. Simple experiments to confirm the theoretical findings are recommended. Favorable agreement between such experiments and the present theory may argue well for the extension of the analytic results to predict fluid performance in future large length scale capillary fluid systems for spacecraft as well as for small scale capillary systems on Earth.

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

NASA Astrophysics Data System (ADS)

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 electrophoresis-electrochemistry microfluidic system for the determination of organic peroxides

NASA Technical Reports Server (NTRS)

Wang, Joseph; Escarpa, Alberto; Pumera, Martin; Feldman, Jason; Svehla, D. (Principal Investigator)

2002-01-01

A microfluidic analytical system for the separation and detection of organic peroxides, based on a microchip capillary electrophoresis device with an integrated amperometric detector, was developed. The new microsystem relies on the reductive detection of both organic acid peroxides and hydroperoxides at -700 mV (vs. Ag wire/AgCl). Factors influencing the separation and detection processes were examined and optimized. The integrated microsystem offers rapid measurements (within 130 s) of these organic-peroxide compounds, down to micromolar levels. A highly stable response for repetitive injections (RSD 0.35-3.12%; n = 12) reflects the negligible electrode passivation. Such a "lab-on-a-chip" device should be attractive for on-site analysis of organic peroxides, as desired for environmental screening and industrial monitoring.

Physicochemical application of capillary chromatography

NASA Astrophysics Data System (ADS)

Vasil'ev, A. V.; Aleksandrov, E. N.

1992-04-01

The application of capillary gas chromatography in the determination of the free energy, enthalpy, and entropy of sorption, the saturated vapour pressure and activity coefficients, the assessment of the lipophilicity of volatile compounds, and the study of the properties of polymers and liquid crystals is described. The use of reaction cappillary chromatography in kinetic studies of conformational conversions, thermal degradation, and photochemical reactions is examined. Studies on the use of capillary columns for determination of the second virial coefficients and viscosity of gases and the diffusion coefficients in gases, liquids, supercritical fluids, and polymers are analysed. The bibliography includes 114 references.

Multiple positive solutions for a class of integral inclusions

NASA Astrophysics Data System (ADS)

Hong, Shihuang

2008-04-01

This paper deals with sufficient conditions for the existence of at least two positive solutions for a class of integral inclusions arising in the traffic theory. To show our main results, we apply a norm-type expansion and compression fixed point theorem for multivalued map due to Agarwal and O'Regan [A note on the existence of multiple fixed points for multivalued maps with applications, J. Differential Equation 160 (2000) 389-403].

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

PubMed

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.

Gas/oil capillary pressure at chalk at elevated pressures

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

Christoffersen, K.R.; Whitson, C.H.

1995-09-01

Accurate capillary pressure curves are essential for studying the recovery of oil by gas injection in naturally fractured chalk reservoirs. A simple and fast method to determine high-pressure drainage capillary pressure curves has been developed. The effect of gas/oil interfacial tension (IFT) on the capillary pressure of chalk cores has been determined for a methane/n-pentane system. Measurements on a 5-md outcrop chalk core were made at pressures of 70, 105, and 130 bar, with corresponding IFT`s of 6.3, 3.2, and 1.5 mN/m. The results were both accurate and reproducible. The measured capillary pressure curves were not a linear function ofmore » IFT when compared with low-pressure centrifuge data. Measured capillary pressures were considerably lower than IFT-scaled centrifuge data. It appears that the deviation starts at an IFT of about 5 mN/m. According to the results of this study, the recovery of oil by gravity drainage in naturally fractured chalk reservoirs may be significantly underestimated if standard laboratory capillary pressure curves are scaled by IFT only. However, general conclusions cannot be made on the basis on only this series of experiments on one chalk core.« less

Capillary Movement in Substrates in Microgravity

NASA Technical Reports Server (NTRS)

Bula, R. J.; Duffie, N. A.

1996-01-01

A more complete understanding of the dynamics of capillary flow through an unsaturated porous medium would be useful for a number of space and terrestrial applications. Knowledge of capillary migration of liquids in granular beds in microgravity would significantly enhance the development and understanding of how a matrix based nutrient delivery system for the growth of plants would function in a microgravity environment. Thus, such information is of interest from the theoretical as well as practical point of view.

Multi-photon microfabrication of three-dimensional capillary-scale vascular networks

NASA Astrophysics Data System (ADS)

Skylar-Scott, Mark A.; Liu, Man-Chi; Wu, Yuelong; Yanik, Mehmet Fatih

2017-02-01

Biomimetic models of microvasculature could enable assays of complex cellular behavior at the capillary-level, and enable efficient nutrient perfusion for the maintenance of tissues. However, existing three-dimensional printing methods for generating perfusable microvasculature with have insufficient resolution to recapitulate the microscale geometry of capillaries. Here, we present a collection of multiphoton microfabrication methods that enable the production of precise, three-dimensional, branched microvascular networks in collagen. When endothelial cells are added to the channels, they form perfusable lumens with diameters as small as 10 μm. Using a similar photochemistry, we also demonstrate the micropatterning of proteins embedded in microfabricated collagen scaffolds, producing hybrid scaffolds with both defined microarchitecture with integrated gradients of chemical cues. We provide examples for how these hybrid microfabricated scaffolds could be used in angiogenesis and cell homing assays. Finally, we describe a new method for increasing the micropatterning speed by synchronous laser and stage scanning. Using these technologies, we are working towards large-scale (>1 cm), high resolution ( 1 μm) scaffolds with both microarchitecture and embedded protein cues, with applications in three-dimensional assays of cellular behavior.

Severe developmental delay and multiple strawberry naevi: a new syndrome?

PubMed Central

Upton, C J; Young, I D

1993-01-01

An 18 month old girl with dysmorphic features, severe developmental delay, multiple strawberry naevi, and capillary naevi is described. No previous report of a similar association of features has been identified. Images PMID:8230170

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

NASA Astrophysics Data System (ADS)

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

2018-05-01

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

Principles of Micellar Electrokinetic Capillary Chromatography Applied in Pharmaceutical Analysis

PubMed Central

Hancu, Gabriel; Simon, Brigitta; Rusu, Aura; Mircia, Eleonora; Gyéresi, Árpád

2013-01-01

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. PMID:24312804

A comparison of capillary hydraulic conductivities in postural and locomotor muscle.

PubMed

McDonagh, P F; Gore, R W

1982-09-01

In a comparative skeletal muscle study Folkow and Halicka (Microvasc. Res. 1: 1-14, 1968) reported that the capillary filtration coefficient (CFC) of postural (red) muscle was two times the CFC of locomotor (white) muscle. It was concluded that the twofold difference in CFC was due solely to a difference in the perfused capillary surface areas (Sf) of red vs. white muscle. However, CFC is the product of capillary hydraulic conductivity (LP) and Sf. Hence their conclusion assumed that the average LP of red muscle capillaries is exactly equal to the average LP of white muscle capillaries. The following study was undertaken to test the validity of this assumption. The microocclusion procedures and analytical model described by Lee et al. (Circ. Res. 28: 358-370, 1971) and Gore [Am. J. Physiol. 242 (Heart Circ. Physiol. 11): H268-H287, 1982] were used to determine LP. Independent measurements of LP were recorded from single capillaries in red, anterior latissimus dorsi (ALD) and white, posterior latissimus dorsi (PLD) muscles of chickens anesthetized with L.A. Thesia. We found that the mean capillary hydraulic conductivity in postural muscle [(LP)ALD = 0.20 +/- 0.06 (SE) micrometers . s-1 . cmH2O-1 (n = 11)] was significantly different from the mean capillary hydraulic conductivity in locomotor muscle [(LP)PLD = 0.061 +/- 0.01 micrometers . s-1 . cmH2O-1 (n = 14)] (P less than 0.05). These results provide direct evidence that observed differences in red vs. white muscle CFC's may not be due solely to different perfused capillary surface areas but may also be due to differences in capillary hydraulic conductivity.

Recent applications of nanomaterials in capillary electrophoresis.

PubMed

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.

Comparison of 5 reflectance meters for capillary blood glucose determination.

PubMed

Kolopp, M; Louis, J; Pointel, J P; Kohler, F; Drouin, P; Debry, G

1983-03-01

Manufacturing quality, accuracy and users opinion (i.e. medical and nurses staff and patients) were compared among five Destrostix reading reflectance-meters for home-blood-glucose-monitoring. Two machines (dextrometer and glucometer) equipped with microprocessors, integrated circuits and good quality wiring are best made. Reflectance-meter capillary blood glucose measurements were found to be accurate enough for home-blood-glucose-monitoring, compared to a reference method. However, two machines from the same brand were different in blood glucose accuracy. Glucocheck had poorest results. Users prefer small sized, battery powered machines. Glucometer appears to be best suited to home-blood-glucose-monitoring.

Capillary toroid cavity detector for high pressure NMR

DOEpatents

Gerald, II, Rex E.; Chen, Michael J.; Klingler, Robert J.; Rathke, Jerome W.; ter Horst, Marc

2007-09-11

A Toroid Cavity Detector (TCD) is provided for implementing nuclear magnetic resonance (NMR) studies of chemical reactions under conditions of high pressures and temperatures. A toroid cavity contains an elongated central conductor extending within the toroid cavity. The toroid cavity and central conductor generate an RF magnetic field for NMR analysis. A flow-through capillary sample container is located within the toroid cavity adjacent to the central conductor to subject a sample material flowing through the capillary to a static magnetic field and to enable NMR spectra to be recorded of the material in the capillary under a temperature and high pressure environment.

Thin film capillary process and apparatus

DOEpatents

Yu, Conrad M.

2003-11-18

Method and system of forming microfluidic capillaries in a variety of substrate materials. A first layer of a material such as silicon dioxide is applied to a channel etched in substrate. A second, sacrificial layer of a material such as a polymer is deposited on the first layer. A third layer which may be of the same material as the first layer is placed on the second layer. The sacrificial layer is removed to form a smooth walled capillary in the substrate.

Dispersion and viscous attenuation of capillary waves with finite amplitude

NASA Astrophysics Data System (ADS)

Denner, Fabian; Paré, Gounséti; Zaleski, Stéphane

2017-04-01

We present a comprehensive study of the dispersion of capillary waves with finite amplitude, based on direct numerical simulations. The presented results show an increase of viscous attenuation and, consequently, a smaller frequency of capillary waves with increasing initial wave amplitude. Interestingly, however, the critical wavenumber as well as the wavenumber at which the maximum frequency is observed remain the same for a given two-phase system, irrespective of the wave amplitude. By devising an empirical correlation that describes the effect of the wave amplitude on the viscous attenuation, the dispersion of capillary waves with finite initial amplitude is shown to be, in very good approximation, self-similar throughout the entire underdamped regime and independent of the fluid properties. The results also shown that analytical solutions for capillary waves with infinitesimal amplitude are applicable with reasonable accuracy for capillary waves with moderate amplitude.

Means and method for capillary zone electrophoresis with laser-induced indirect fluorescence detection

DOEpatents

Yeung, Edward S.; Kuhr, Werner G.

1996-02-20

A means and method for capillary zone electrphoresis with laser-induced indirect fluorescence detection. A detector is positioned on the capillary tube of a capillary zone electrophoresis system. The detector includes a laser which generates a laser beam which is imposed upon a small portion of the capillary tube. Fluorescence of the elutant electromigrating through the capillary tube is indirectly detected and recorded.

Means and method for capillary zone electrophoresis with laser-induced indirect fluorescence detection

DOEpatents

Yeung, Edwards; Kuhr, Werner G.

1991-04-09

A means and method for capillary zone electrphoresis with laser-induced indirect fluorescence detection. A detector is positioned on the capillary tube of a capillary zone electrophoresis system. The detector includes a laser which generates a laser beam which is imposed upon a small portion of the capillary tube. Fluorescence of the elutant electromigrating through the capillary tube is indirectly detected and recorded.

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

NASA Astrophysics Data System (ADS)

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

2017-12-01

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

Exploring Ultimate Water Capillary Evaporation in Nanoscale Conduits.

PubMed

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.

R-134a qualification -- industry refrigerator capillary data

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

DeVos, R.

1997-12-31

With the phaseout of R-12, the use of R-134a and polyolester (POE) oil became the preferred refrigerant/oil combination for the refrigerator appliance industry. Reliability data for this refrigerant/oil combination were minimal, and initial testing showed a propensity for the capillary tubes to clog with a variety of contaminants. A test was designed by an industry group to accelerate the process of contamination and capillary plugging. This paper presents capillary tube stress test data that were developed for this group by its member companies. This study investigated the relationship between capillary tube restriction levels and variables including compressor type, oil type,more » chlorine level, and moisture level. Analysis of the contaminants included a visual description, infrared spectroscopy, scanning electron microscope examination, and measurements of total chlorine content and noncondensable gas content of the refrigerant. Oil samples were measured for moisture level, dissolved iron, and total acid, and an infrared spectral analysis was performed.« less

Novel concept of washing for microfluidic paper-based analytical devices based on capillary force of paper substrates.

PubMed

Mohammadi, Saeed; Busa, Lori Shayne Alamo; Maeki, Masatoshi; Mohamadi, Reza M; Ishida, Akihiko; Tani, Hirofumi; Tokeshi, Manabu

2016-11-01

A novel washing technique for microfluidic paper-based analytical devices (μPADs) that is based on the spontaneous capillary action of paper and eliminates unbound antigen and antibody in a sandwich immunoassay is reported. Liquids can flow through a porous medium (such as paper) in the absence of external pressure as a result of capillary action. Uniform results were achieved when washing a paper substrate in a PDMS holder which was integrated with a cartridge absorber acting as a porous medium. Our study demonstrated that applying this washing technique would allow μPADs to become the least expensive microfluidic device platform with high reproducibility and sensitivity. In a model μPAD assay that utilized this novel washing technique, C-reactive protein (CRP) was detected with a limit of detection (LOD) of 5 μg mL -1 . Graphical Abstract A novel washing technique for microfluidic paper-based analytical devices (μPADs) that is based on the spontaneous capillary action of paper and eliminates unbound antigen and antibody in a sandwich immunoassay is reported.

Insulin-induced changes in microvascular vasomotion and capillary recruitment are associated in humans.

PubMed

de Boer, Michiel P; Meijer, Rick I; Newman, John; Stehouwer, Coen D A; Eringa, Etto C; Smulders, Yvo M; Serné, Erik H

2014-07-01

Insulin-induced capillary recruitment is considered a significant regulator of overall insulin-stimulated glucose uptake. Insulin's action to recruit capillaries has been hypothesized to involve insulin-induced changes in vasomotion. Data directly linking vasomotion to capillary perfusion, however, are presently lacking. We, therefore, investigated whether insulin's actions on capillary recruitment and vasomotion were interrelated in a group of healthy individuals. We further assessed the role of capillary recruitment in the association between vasomotion and insulin-mediated glucose uptake. Changes in vasomotion and capillary density were determined by LDF and capillary videomicroscopy in skin, respectively, before and during a hyperinsulinemic euglycemic clamp in 19 healthy volunteers. Insulin-induced increase in the neurogenic vasomotion domain was positively related to insulin-augmented capillary recruitment (r = 0.51, p = 0.04), and both parameters were related to insulin-mediated glucose uptake (r = 0.47, p = 0.06 and r = 0.73, p = 0.001, respectively). The change in insulin-augmented capillary recruitment could, at least statistically, largely explain the association between the neurogenic domain and insulin-mediated glucose uptake. Insulin-induced changes in vasomotion and capillary recruitment are associated in healthy volunteers. These data suggest that insulin's action to recruit capillaries may in part involve action on the neurogenic vasomotion domain, thereby enhancing capillary perfusion and glucose uptake. © 2014 John Wiley & Sons Ltd.

A modular and low­cost 3D­-printed microfluidic device with assembly of capillaries for droplet mass production

NASA Astrophysics Data System (ADS)

Aguirre-Pablo, A. A.; Zhang, J. M.; Li, E. Q.; Thoroddsen, S. T.

2015-11-01

We report a new 3D­-printed microfluidic system with assembly of capillaries for droplet generation. The system consists of the following parts: 3D­printed Droplet Generation Units (DGUs) with embedded capillaries and two 3D-printed pyramid distributors for supplying two different fluid phases into every DGU. A single DGU consists of four independent parts: a top channel, a bottom channel, a capillary and a sealing gasket. All components are produced by 3d­printing except the capillaries, which are formed in a glass-­puller. DGUs are independent of the distributor and from each other; they can easily be assembled, replaced and modified due to its modular design which is an advantage in case of a faulty part or clogging, eliminating the need to fabricate a complete new system which is cost and time demanding. We assessed the feasibility of producing droplets in this device varying different fluid parameters, such as liquid viscosity and flow rate, which affect droplet size and generation frequency. The design and fabrication of this device is simple and low­-cost with the 3D printing technology. Due to the modular design of independent parts, low-cost fabrication and easy parallelization of multiple DGU's, this system provides great flexibility for industrial applications.

77 FR 74027 - Certain Integrated Circuit Packages Provided with Multiple Heat-Conducting Paths and Products...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-12-12

... INTERNATIONAL TRADE COMMISSION [Investigation No. 337-TA-851] Certain Integrated Circuit Packages Provided with Multiple Heat- Conducting Paths and Products Containing Same; Commission Determination Not To... provided with multiple heat-conducting paths and products containing same by reason of infringement of...

The Effect of Sensory Integration Treatment on Children with Multiple Disabilities.

ERIC Educational Resources Information Center

Din, Feng S.; Lodato, Donna M.

Six children with multiple disabilities (ages 5 to 8) participated in this evaluation of the effect of sensory integration treatment on sensorimotor function and academic learning. The children had cognitive abilities ranging from sub-average to significantly sub-average, three were non-ambulatory, one had severe behavioral problems, and each…

Demonstration of a high repetition rate capillary discharge waveguide

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

Gonsalves, A. J., E-mail: ajgonsalves@lbl.gov; Pieronek, C.; Daniels, J.

2016-01-21

A hydrogen-filled capillary discharge waveguide operating at kHz repetition rates is presented for parameters relevant to laser plasma acceleration (LPA). The discharge current pulse was optimized for erosion mitigation with laser guiding experiments and MHD simulation. Heat flow simulations and measurements showed modest temperature rise at the capillary wall due to the average heat load at kHz repetition rates with water-cooled capillaries, which is promising for applications of LPAs such as high average power radiation sources.

A retrospective likelihood approach for efficient integration of multiple omics factors in case-control association studies.

PubMed

Balliu, Brunilda; Tsonaka, Roula; Boehringer, Stefan; Houwing-Duistermaat, Jeanine

2015-03-01

Integrative omics, the joint analysis of outcome and multiple types of omics data, such as genomics, epigenomics, and transcriptomics data, constitute a promising approach for powerful and biologically relevant association studies. These studies often employ a case-control design, and often include nonomics covariates, such as age and gender, that may modify the underlying omics risk factors. An open question is how to best integrate multiple omics and nonomics information to maximize statistical power in case-control studies that ascertain individuals based on the phenotype. Recent work on integrative omics have used prospective approaches, modeling case-control status conditional on omics, and nonomics risk factors. Compared to univariate approaches, jointly analyzing multiple risk factors with a prospective approach increases power in nonascertained cohorts. However, these prospective approaches often lose power in case-control studies. In this article, we propose a novel statistical method for integrating multiple omics and nonomics factors in case-control association studies. Our method is based on a retrospective likelihood function that models the joint distribution of omics and nonomics factors conditional on case-control status. The new method provides accurate control of Type I error rate and has increased efficiency over prospective approaches in both simulated and real data. © 2015 Wiley Periodicals, Inc.

Stress failure of pulmonary capillaries: role in lung and heart disease

NASA Technical Reports Server (NTRS)

West, J. B.; Mathieu-Costello, O.

1992-01-01

Pulmonary capillaries have extremely thin walls to allow rapid exchange of respiratory gases across them. Recently it has been shown that the wall stresses become very large when the capillary pressure is raised, and in anaesthetised rabbits, ultrastructural damage to the walls is seen at pressures of 40 mm Hg and above. The changes include breaks in the capillary endothelial layer, alveolar epithelial layer, and sometimes all layers of the wall. The strength of the thin part of the capillary wall can be attributed to the type IV collagen in the extracellular matrix. Stress failure of pulmonary capillaries results in a high-permeability form of oedema, or even frank haemorrhage, and is apparently the mechanism of neurogenic pulmonary oedema and high-altitude pulmonary oedema. It also explains the exercise-induced pulmonary haemorrhage that occurs in all racehorses. Several features of mitral stenosis are consistent with stress failure. Overinflation of the lung also leads to stress failure, a common cause of increased capillary permeability in the intensive care environment. Stress failure also occurs if the type IV collagen of the capillary wall is weakened by autoantibodies as in Goodpasture's syndrome. Neutrophil elastase degrades type IV collagen and this may be the starting point of the breakdown of alveolar walls that is characteristic of emphysema. Stress failure of pulmonary capillaries is a hitherto overlooked and potentially important factor in lung and heart disease.

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

PubMed Central

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

Laser absorption waves in metallic capillaries

NASA Astrophysics Data System (ADS)

Anisimov, V. N.; Arutiunian, R. V.; Bol'Shov, L. A.; Kanevskii, M. F.; Kondrashov, V. V.

1987-07-01

The propagation of laser absorption waves in metallic capillaries was studied experimentally and numerically during pulsed exposure to CO2 laser radiation. The dependence of the plasma front propagation rate on the initial air pressure in the capillary is determined. In a broad range of parameters, the formation time of the optically opaque plasma layer is governed by the total laser pulse energy from the beginning of the exposure to the instant screening appears, and is weakly dependent on the pulse shape and gas pressure.

Sample preconcentration with chemical derivatization in capillary electrophoresis. Capillary as preconcentrator, microreactor and chiral selector for high-throughput metabolite screening.

PubMed

Ptolemy, Adam S; Britz-McKibbin, Philip

2006-02-17

New strategies for integrating sample pretreatment with chemical analyses under a single format is required for rapid, sensitive and enantioselective analyses of low abundance metabolites in complex biological samples. Capillary electrophoresis (CE) offers a unique environment for controlling analyte/reagent band dispersion and electromigration properties using discontinuous electrolyte systems. Recent work in our laboratory towards developing a high-throughput CE platform for low abundance metabolites via on-line sample preconcentration with chemical derivatization (SPCD) is primarily examined in this review, as there have been surprisingly only a few strategies reported in the literature to date. In-capillary sample preconcentration serves to enhance concentration sensitivity via electrokinetic focusing of long sample injection volumes for lower detection limits, whereas chemical derivatization by zone passing is used to expand detectability and selectivity, notably for enantiomeric resolution of metabolites lacking intrinsic chromophores using nanolitre volumes of reagent. Together, on-line SPCD-CE can provide over a 100-fold improvement in concentration sensitivity, shorter total analysis times, reduced sample handling and improved reliability for a variety of amino acid and amino sugar metabolites, which is also amenable to automated high-throughput screening. This review will highlight basic method development and optimization parameters relevant to SPCD-CE, including applications to bacterial metabolite flux and biomarker analyses. Insight into the mechanism of analyte focusing and labeling by SPCD-CE is also discussed, as well as future directions for continued research.

Direct measurement of capillary blood pressure in the human lip

NASA Technical Reports Server (NTRS)

Parazynski, S. E.; Tucker, B. J.; Aratow, M.; Crenshaw, A.; Hargens, A. R.

1993-01-01

In this study, we developed and tested a new procedure for measuring microcirculatory blood pressures above heart level in humans. Capillary and postcapillary venule blood pressures were measured directly in 13 human subjects by use of the servonulling micropressure technique adapted for micropuncture of lip capillaries. Pressure waveforms were recorded in 40 separate capillary vessels and 14 separate postcapillary venules over periods ranging from 5 to 64 s. Localization and determination of capillary and postcapillary vessels were ascertained anatomically before pressure measurements. Capillary pressure was 33.2 +/- 1.5 (SE) mm Hg in lips of subjects seated upright. Repeated micropunctures of the same vessel gave an average coefficient of variation of 0.072. Postcapillary venule pressure was 18.9 +/- 1.6 mm Hg. This procedure produces a direct and reproducible means of measuring microvascular blood pressures in a vascular bed above heart level in humans.

Dual-opposite injection capillary electrophoresis: Principles and misconceptions.

PubMed

Blackney, Donna M; Foley, Joe P

2017-03-01

Dual-opposite injection capillary electrophoresis (DOI-CE) is a separation technique that utilizes both ends of the capillary for sample introduction. The electroosmotic flow (EOF) is suppressed to allow all ions to reach the detector quickly. Depending on the individual electrophoretic mobilities of the analytes of interest and the effective length that each analyte travels to the detection window, the elution order of analytes in a DOI-CE separation can vary widely. This review discusses the principles, applications, and limitations of dual-opposite injection capillary electrophoresis. Common misconceptions regarding DOI-CE are clarified. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Screening of neuraminidase inhibitors from traditional Chinese medicines by integrating capillary electrophoresis with immobilized enzyme microreactor.

PubMed

Zhao, Haiyan; Chen, Zilin

2014-05-02

A simple and effective neuraminidase-immobilized capillary microreactor was fabricated by glutaraldehyde cross-linking technology for screening the neuraminidase inhibitors from traditional Chinese medicines. The substrate and product were separated by CE in short-end injection mode within 2 min. Dual-wavelength ultraviolet detection was employed to eliminate the interference from the screened compounds. The parameters relating to the separation efficiency and the activity of immobilized neuraminidase were systematically evaluated. The activity of the immobilized neuraminidase remained 90% after 30 days storage at 4°C. The immobilized NA microreactor could be continuously used for more than 200 runs. The Michaelis-Menten constant of neuraminidase was determined by the microreactor as 136.6 ± 10.8 μM. In addition, six in eighteen natural products were found as potent inhibitors and the inhibition potentials were ranked in the following order: bavachinin>bavachin>baicalein>baicalin>chrysin and vitexin. The half-maximal inhibitory concentrations were 59.52 ± 4.12, 65.28 ± 1.07, 44.79 ± 1.21 and 31.62 ± 2.04 for baicalein, baicalin, bavachin and bavachinin, respectively. The results demonstrated that the neuraminidase-immobilized capillary microreactor was a very effective tool for screening neuraminidase inhibitors from traditional Chinese medicines. Copyright © 2014 Elsevier B.V. All rights reserved.

Assessment of the capillary zone electrophoretic behavior of proteins in the presence of electroosmotic modifiers: protein-polyamine interaction studied using a polyacrylamide-coated capillary.

PubMed

Kubo, K; Hattori, A

2001-10-01

The use of polyamines as electroosmotic modifiers has been shown to be effective in enhancing resolution of protein glycoforms in capillary zone electrophoresis (CZE) using a bare capillary tube. In this study, effectiveness was evaluated by using a polyacrylamide-coated capillary tube instead of a bare capillary tube. Electropherograms obtained in the presence of polyamines were inferior to those obtained in their absence with respect to resolution. Electrophoretic mobility of the proteins decreased and their peaks were broadened by polyamines bound to them. This unfavorable effect was dependent on both the species of polyamines and the pH values of the electrolyte buffer. The reduction of resolution caused by polyamines was in the following order: spermidine (SPD) approximately spermidine-tri-hydrochloride (SPD-HCI) > putrescine (PUT) > hexamethonium chloride (HMC). The observed effect can be ascribed to the formation of complexes between the proteins and the polyamines. In addition, for the bare capillary tube the complexes showed interaction with the inner surface, resulting in local suppression of electroosmosis and poor resolution. The high resolution obtained in the coated capillary tube was reduced in the presence of the polyamines. Thus, the use of the polyamines has a negative effect on the analysis of protein microheterogeneity as a result of protein-polyamine interaction.

Integrity Verification for Multiple Data Copies in Cloud Storage Based on Spatiotemporal Chaos

NASA Astrophysics Data System (ADS)

Long, Min; Li, You; Peng, Fei

Aiming to strike for a balance between the security, efficiency and availability of the data verification in cloud storage, a novel integrity verification scheme based on spatiotemporal chaos is proposed for multiple data copies. Spatiotemporal chaos is implemented for node calculation of the binary tree, and the location of the data in the cloud is verified. Meanwhile, dynamic operation can be made to the data. Furthermore, blind information is used to prevent a third-party auditor (TPA) leakage of the users’ data privacy in a public auditing process. Performance analysis and discussion indicate that it is secure and efficient, and it supports dynamic operation and the integrity verification of multiple copies of data. It has a great potential to be implemented in cloud storage services.

Multiplicity and Self-Identity: Trauma and Integration in Shirley Mason's Art

ERIC Educational Resources Information Center

Thompson, Geoffrey

2011-01-01

This viewpoint appeared in its original form as the catalogue essay that accompanied the exhibition "Multiplicity and Self-Identity: Trauma and Integration in Shirley Mason's Art," curated by the author for Gallery 2110, Sacramento, CA, and the 2010 Annual Conference of the American Art Therapy Association. The exhibition featured 17 artworks by…

Multicomponent micropatterned sol-gel materials by capillary molding

NASA Astrophysics Data System (ADS)

Lochhead, Michael J.; Yager, Paul

1997-10-01

A physically and chemically benign method for patterning multiple sol-gel materials onto a single substrate is described. Structures are demonstrated for potential micro- optical chemical sensor, biosensor, and waveguiding applications. Fabrication is based on the micro molding in capillaries (MIMIC) approach. A novel mold design allows several sols to be cast simultaneously. Closely spaced, organically modified silica ridges containing fluorescent dyes are demonstrated. Ridges have cross sectional dimensions from one to 50 micrometers and are centimeters in length. Processing issues, particularly those related to mold filling, are discussed in detail. Because sol-gel MIMIC avoids the harsh physical and chemical environments normally associated with patterning, the approach allows full exploitation of sol- gel processing advantages, such as the ability to entrap sensitive organic dopant molecules in the sol-gel matrix.

Silicon ribbon growth by a capillary action shaping technique

NASA Technical Reports Server (NTRS)

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

1976-01-01

The crystal growth method described is a capillary action shaping technique. Meniscus shaping for the desired ribbon geometry occurs at the vertex of a wettable die. As ribbon growth depletes the melt meniscus, capillary action supplies replacement material. A capillary die is so designed that the bounding edges of the die top are not parallel or concentric with the growing ribbon. The new dies allow a higher melt meniscus with concomitant improvements in surface smoothness and freedom from SiC surface particles, which can degrade perfection.

Real object-based 360-degree integral-floating display using multiple depth camera

NASA Astrophysics Data System (ADS)

Erdenebat, Munkh-Uchral; Dashdavaa, Erkhembaatar; Kwon, Ki-Chul; Wu, Hui-Ying; Yoo, Kwan-Hee; Kim, Young-Seok; Kim, Nam

2015-03-01

A novel 360-degree integral-floating display based on the real object is proposed. The general procedure of the display system is similar with conventional 360-degree integral-floating displays. Unlike previously presented 360-degree displays, the proposed system displays the 3D image generated from the real object in 360-degree viewing zone. In order to display real object in 360-degree viewing zone, multiple depth camera have been utilized to acquire the depth information around the object. Then, the 3D point cloud representations of the real object are reconstructed according to the acquired depth information. By using a special point cloud registration method, the multiple virtual 3D point cloud representations captured by each depth camera are combined as single synthetic 3D point cloud model, and the elemental image arrays are generated for the newly synthesized 3D point cloud model from the given anamorphic optic system's angular step. The theory has been verified experimentally, and it shows that the proposed 360-degree integral-floating display can be an excellent way to display real object in the 360-degree viewing zone.

Adaptive Estimation of Multiple Fading Factors for GPS/INS Integrated Navigation Systems.

PubMed

Jiang, Chen; Zhang, Shu-Bi; Zhang, Qiu-Zhao

2017-06-01

The Kalman filter has been widely applied in the field of dynamic navigation and positioning. However, its performance will be degraded in the presence of significant model errors and uncertain interferences. In the literature, the fading filter was proposed to control the influences of the model errors, and the H-infinity filter can be adopted to address the uncertainties by minimizing the estimation error in the worst case. In this paper, a new multiple fading factor, suitable for the Global Positioning System (GPS) and the Inertial Navigation System (INS) integrated navigation system, is proposed based on the optimization of the filter, and a comprehensive filtering algorithm is constructed by integrating the advantages of the H-infinity filter and the proposed multiple fading filter. Measurement data of the GPS/INS integrated navigation system are collected under actual conditions. Stability and robustness of the proposed filtering algorithm are tested with various experiments and contrastive analysis are performed with the measurement data. Results demonstrate that both the filter divergence and the influences of outliers are restrained effectively with the proposed filtering algorithm, and precision of the filtering results are improved simultaneously.

A Methodology for Multiple Rule System Integration and Resolution Within a Singular Knowledge Base

NASA Technical Reports Server (NTRS)

Kautzmann, Frank N., III

1988-01-01

Expert Systems which support knowledge representation by qualitative modeling techniques experience problems, when called upon to support integrated views embodying description and explanation, especially when other factors such as multiple causality, competing rule model resolution, and multiple uses of knowledge representation are included. A series of prototypes are being developed to demonstrate the feasibility of automating the process of systems engineering, design and configuration, and diagnosis and fault management. A study involves not only a generic knowledge representation; it must also support multiple views at varying levels of description and interaction between physical elements, systems, and subsystems. Moreover, it will involve models of description and explanation for each level. This multiple model feature requires the development of control methods between rule systems and heuristics on a meta-level for each expert system involved in an integrated and larger class of expert system. The broadest possible category of interacting expert systems is described along with a general methodology for the knowledge representation and control of mutually exclusive rule systems.

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

PubMed Central

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

2017-01-01

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

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

PubMed Central

2016-01-01

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

Early changes in fiber profile and capillary density in long-term stimulated muscles.

PubMed

Hudlická, O; Dodd, L; Renkin, E M; Gray, S D

1982-10-01

Predominantly fast skeletal muscles of rabbits [tibialis anterior (TA), extensor digitorum longus (EDL)] were stimulated at a frequency naturally occurring in nerves to slow muscles (10 Hz continuously) for 8 h/day for 2--4 days. Such stimulation is known to convert all glycolytic fibers to oxidative and to increase capillary density. Our aim was to study early stages of conversion to investigate the factors responsible for the changes. Staining of quick-frozen sections for myosin ATPase, succinic dehydrogenase, and alkaline phosphatase was used to study the distribution of different fiber types and to measure fiber cross-sectional areas, capillaries per square millimeter, and capillary-to-fiber ratios in each fiber category. TA but not EDL showed conversion of fast glycolytic to fast oxidative fibers after 2 days, more after 4 days of stimulation. In both muscles, the largest fast glycolytic fibers were diminished in number after stimulation. There was significant increase in total capillaries per square millimeter after 4 days and some increase after 2 days of stimulation. The increase in capillaries per square millimeter exceeded the increase in the number of fibers per square millimeter, and since there was no change in mean fiber area, the increase is attributed to capillary growth. In EDL, there was an increase in the number of capillaries supplying both fast glycolytic and fast oxidative fibers, suggesting that capillary growth precedes fiber type conversion. In TA, the number of capillaries supplying fast oxidative fibers was increased but that to fast glycolytic fibers, was not. This is consistent with capillary growth simultaneous with or following fiber conversion. In both TA and EDL the number of capillaries perfused after contraction was higher in stimulated muscles, suggesting that increased capillary flow contributed to capillary growth.

Affinity capillary electrophoresis for studying interactions in life sciences.

PubMed

Olabi, Mais; Stein, Matthias; Wätzig, Hermann

2018-05-10

Affinity capillary electrophoresis (ACE) analyzes noncovalent interactions between ligands and analytes based on changes in their electrophoretic mobility. This technique has been widely used to investigate various biomolecules, mainly proteins, polysaccharides and hormones. ACE is becoming a technique of choice to validate high throughput screening results, since it is very predictively working in realistic and relevant media, e.g. in body fluids. It is highly recommended to incorporate ACE as a powerful analytical tool to properly prepare animal testing and preclinical studies. The interacting molecules can be found free in solution or can be immobilized to a solid support. Thus, ACE is classified in two modes, free solution ACE and immobilized ACE. Every ACE mode has advantages and disadvantages. Each can be used for a variety of applications. This review covers literature of scopus and SciFinder data base in the period from 2016 until beginning 2018, including the keywords "affinity capillary electrophoresis", "immunoaffinity capillary electrophoresis", "immunoassay capillary electrophoresis" and "immunosorbent capillary electrophoresis". More than 200 articles have been found and 112 have been selected and thoroughly discussed. During this period, the data processing and the underlying calculations in mobility shift ACE (ms ACE), frontal analysis ACE (FA ACE) and plug-plug kinetic capillary electrophoresis (ppKCE) as mostly applied free solution techniques have substantially improved. The range of applications in diverse free solution and immobilized ACE techniques has been considerably broadened. Copyright © 2018. Published by Elsevier Inc.

77 FR 33486 - Certain Integrated Circuit Packages Provided With Multiple Heat-Conducting Paths and Products...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-06-06

... INTERNATIONAL TRADE COMMISSION [Docket No. 2899] Certain Integrated Circuit Packages Provided With... complaint entitled Certain Integrated Circuit Packages Provided With Multiple Heat-Conducting Paths and..., telephone (202) 205-2000. The public version of the complaint can be accessed on the Commission's electronic...

Mathematical and computational studies of equilibrium capillary free surfaces

NASA Technical Reports Server (NTRS)

Albright, N.; Chen, N. F.; Concus, P.; Finn, R.

1977-01-01

The results of several independent studies are presented. The general question is considered of whether a wetting liquid always rises higher in a small capillary tube than in a larger one, when both are dipped vertically into an infinite reservoir. An analytical investigation is initiated to determine the qualitative behavior of the family of solutions of the equilibrium capillary free-surface equation that correspond to rotationally symmetric pendent liquid drops and the relationship of these solutions to the singular solution, which corresponds to an infinite spike of liquid extending downward to infinity. The block successive overrelaxation-Newton method and the generalized conjugate gradient method are investigated for solving the capillary equation on a uniform square mesh in a square domain, including the case for which the solution is unbounded at the corners. Capillary surfaces are calculated on the ellipse, on a circle with reentrant notches, and on other irregularly shaped domains using JASON, a general purpose program for solving nonlinear elliptic equations on a nonuniform quadrilaterial mesh. Analytical estimates for the nonexistence of solutions of the equilibrium capillary free-surface equation on the ellipse in zero gravity are evaluated.

Fast DNA sieving through submicrometer cylindrical glass capillary matrix.

PubMed

Cao, Zhen; Yobas, Levent

2014-01-07

Here, we report on DNA electrophoresis through a novel artificial sieving matrix based on the highly regular submicrometer cylindrical glass capillary segments alternatingly arranged with wells. Such round capillaries pose a higher-order confinement resulting in a lower partition coefficient and greater entropic energy barrier while limiting the driving field strength to a small fraction of the applied electric field. In return, the separation can be performed at high average field strengths (up to 1.6 kV/cm) without encountering the field-dependent loss of resolving power. This leads to fast DNA sieving as demonstrated here on the capillaries of 750 nm in diameter. The 600 bp to 21 kbp long chains are shown to resolve within 4 min after having undergone a fairly limited number of entropic barriers (128 in total). The capillary matrix also exhibits a critical field threshold below which DNA bands fail to launch, and this occurs at a considerably greater magnitude than in other matrixes. The submicrometer capillaries are batch-fabricated on silicon through a fabrication process that does not require high-resolution advanced lithography or well-controlled wafer bonding techniques to define their critical dimension.

Multiple-locus variable-number tandem-repeats analysis of Listeria monocytogenes using multicolour capillary electrophoresis and comparison with pulsed-field gel electrophoresis typing.

PubMed

Lindstedt, Bjørn-Arne; Tham, Wilhelm; Danielsson-Tham, Marie-Louise; Vardund, Traute; Helmersson, Seved; Kapperud, Georg

2008-02-01

The multiple-locus variable-number tandem-repeats analysis (MLVA) method for genotyping has proven to be a fast and reliable typing tool in several bacterial species. MLVA is in our laboratory the routine typing method for Salmonella enterica subsp. enterica serovar Typhimurium and Escherichia coli O157. The gram-positive bacteria Listeria monocytogenes, while not isolated as frequent as S. Typhimurium and E. coli, causes severe illness with an overall mortality rate of 30%. Thus, it is important that any outbreak of this pathogen is detected early and a fast trace to the source can be performed. In view of this, we have used the information provided by two fully sequenced L. monocytogenes strains to develop a MLVA assay coupled with high-resolution capillary electrophoresis and compared it to pulsed-field gel electrophoresis (PFGE) in two sets of isolates, one Norwegian (79 isolates) and one Swedish (61 isolates) set. The MLVA assay could resolve all of the L. monocytogenes serotypes tested, and was slightly more discriminatory than PFGE for the Norwegian isolates (28 MLVA profiles and 24 PFGE profiles) and opposite for the Swedish isolates (42 MLVA profiles and 43 PFGE profiles).

Capillary flow enhancement in rectangular polymer microchannels with a deformable wall.

PubMed

Anoop, R; Sen, A K

2015-07-01

We report the capillary flow enhancement in rectangular polymer microchannels, when one of the channel walls is a deformable polymer membrane. We provide detailed insight into the physics of elastocapillary interaction between the capillary flow and elastic membrane, which leads to significant improvements in capillary flow performance. As liquid flows by capillary action in such channels, the deformable wall deflects inwards due to the Young-Laplace pressure drop across the liquid meniscus. This, in turn, decreases the radius of curvature of the meniscus and increases the driving capillary pressure. A theoretical model is proposed to predict the resultant increase in filling speed and rise height, respectively, in deformable horizontal and vertical microchannels having large aspect ratios. A non-dimensional parameter J, which represents the ratio of the capillary force to the mechanical restoring force, is identified to quantify the elastocapillary effects in terms of the improvement in filling speed (for J>0.238) and the condition for channel collapse (J>1). The theoretical predictions show good agreement with experimental data obtained using deformable rectangular poly(dimethylsiloxane) microchannels. Both model predictions and experimental data show that over 15% improvement in the Washburn coefficient in horizontal channels, and over 30% improvement in capillary rise height in vertical channels, are possible prior to channel collapse. The proposed technique of using deformable membranes as channel walls is a viable method for capillary flow enhancement in microfluidic devices.

Study of the efficiency for ion transfer through bent capillaries.

PubMed

Chen, Tsung-Chi; Xu, Wei; Garimella, Sandilya; Ouyang, Zheng

2012-11-01

Discontinuous atmospheric pressure interfaces (DAPIs) with bent capillaries represent a highly simplified and flexible means for introducing ions into a vacuum manifold for mass analysis or gas phase ion reactions. In this work, a series of capillaries of different radians and curvatures were used with DAPI for studying the impact of the capillary bending on the ion transfer. The variation of transfer efficiency was systematically characterized for dry and solvated ions. The efficiency loss for dry ions was less than one order of magnitude, even with a three-turn bent capillary. The transfer of solvated ions generated by electrospray was found to be minimally impacted by the bending of the transfer capillary. For multiply protonated ions, the transfer efficiency for ions at lower charge states could be relatively well retained, presumably due to the lower reactivity associated with proton transfer reaction and the compensation in intensity by conversion of ions at higher charge states. Copyright © 2012 John Wiley & Sons, Ltd.

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

PubMed

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.

Study of a heat rejection system using capillary pumping

NASA Technical Reports Server (NTRS)

Neal, L. G.; Wanous, D. J.; Clausen, O. W.

1971-01-01

Results of an analytical study investigating the application of capillary pumping to the heat rejection loop of an advanced Rankine cycle power conversion system are presented. The feasibility of the concept of capillary pumping as an alternate to electromagnetic pumping is analytically demonstrated. Capillary pumping is shown to provide a potential for weight and electrical power saving and reliability through the use of redundant systems. A screen wick pump design with arterial feed lines was analytically developed. Advantages of this design are high thermodynamic and hydrodynamic efficiency, which provide a lightweight easily packaged system. Operational problems were identified which must be solved for successful application of capillary pumping. The most important are the development of start up and shutdown procedures, and development of a means of keeping noncondensibles from the system and of earth-bound testing procedures.

Analysis of bovine milk caseins on organic monolithic columns: an integrated capillary liquid chromatography-high resolution mass spectrometry approach for the study of time-dependent casein degradation.

PubMed

Pierri, Giuseppe; Kotoni, Dorina; Simone, Patrizia; Villani, Claudio; Pepe, Giacomo; Campiglia, Pietro; Dugo, Paola; Gasparrini, Francesco

2013-10-25

Casein proteins constitute approximately 80% of the proteins present in bovine milk and account for many of its nutritional and technological properties. The analysis of the casein fraction in commercially available pasteurized milk and the study of its time-dependent degradation is of considerable interest in the agro-food industry. Here we present new analytical methods for the study of caseins in fresh and expired bovine milk, based on the use of lab-made capillary organic monolithic columns. An integrated capillary high performance liquid chromatography and high-resolution mass spectrometry (Cap-LC-HRMS) approach was developed, exploiting the excellent resolution, permeability and biocompatibility of organic monoliths, which is easily adaptable to the analysis of intact proteins. The resolution obtained on the lab-made Protein-Cap-RP-Lauryl-γ-Monolithic column (270 mm × 0.250 mm length × internal diameter, L × I.D.) in the analysis of commercial standard caseins (αS-CN, β-CN and κ-CN) through Cap-HPLC-UV was compared to the one observe using two packed capillary C4 columns, the ACE C4 (3 μm, 150 mm × 0.300 mm, L × I.D.) and the Jupiter C4 column (5 μm, 150 mm × 0.300 mm, L × I.D.). Thanks to the higher resolution observed, the monolithic capillary column was chosen for the successive degradation studies of casein fractions extracted from bovine milk 1-4 weeks after expiry date. The comparison of the UV chromatographic profiles of skim, semi-skim and whole milk showed a major stability of whole milk towards time-dependent degradation of caseins, which was further sustained by high-resolution analysis on a 50-cm long monolithic column using a 120-min time gradient. Contemporarily, the exact monoisotopic and average molecular masses of intact αS-CN and β-CN protein standards were obtained through high resolution mass spectrometry and used for casein identification in Cap-LC-HRMS analysis. Finally, the proteolytic degradation of β-CN in skim milk

Sensory integration balance training in patients with multiple sclerosis: A randomized, controlled trial.

PubMed

Gandolfi, Marialuisa; Munari, Daniele; Geroin, Christian; Gajofatto, Alberto; Benedetti, Maria Donata; Midiri, Alessandro; Carla, Fontana; Picelli, Alessandro; Waldner, Andreas; Smania, Nicola

2015-10-01

Impaired sensory integration contributes to balance disorders in patients with multiple sclerosis (MS). The objective of this paper is to compare the effects of sensory integration balance training against conventional rehabilitation on balance disorders, the level of balance confidence perceived, quality of life, fatigue, frequency of falls, and sensory integration processing on a large sample of patients with MS. This single-blind, randomized, controlled trial involved 80 outpatients with MS (EDSS: 1.5-6.0) and subjective symptoms of balance disorders. The experimental group (n = 39) received specific training to improve central integration of afferent sensory inputs; the control group (n = 41) received conventional rehabilitation (15 treatment sessions of 50 minutes each). Before, after treatment, and at one month post-treatment, patients were evaluated by a blinded rater using the Berg Balance Scale (BBS), Activities-specific Balance Confidence Scale (ABC), Multiple Sclerosis Quality of Life-54, Fatigue Severity Scale (FSS), number of falls and the Sensory Organization Balance Test (SOT). The experimental training program produced greater improvements than the control group training on the BBS (p < 0.001), the FSS (p < 0.002), number of falls (p = 0.002) and SOT (p < 0.05). Specific training to improve central integration of afferent sensory inputs may ameliorate balance disorders in patients with MS. Clinical Trial Registration (NCT01040117). © The Author(s), 2015.

Pulmonary capillary haemangiomatosis: a rare cause of pulmonary hypertension.

PubMed

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.

Intravenous Immunoglobulins Improve Survival in Monoclonal Gammopathy-Associated Systemic Capillary-Leak Syndrome.

PubMed

Pineton de Chambrun, Marc; Gousseff, Marie; Mauhin, Wladimir; Lega, Jean-Christophe; Lambert, Marc; Rivière, Sophie; Dossier, Antoine; Ruivard, Marc; Lhote, François; Blaison, Gilles; Alric, Laurent; Agard, Christian; Saadoun, David; Graveleau, Julie; Soubrier, Martin; Lucchini-Lecomte, Marie-Josée; Christides, Christine; Bosseray, Annick; Levesque, Hervé; Viallard, Jean-François; Tieulie, Nathalie; Lovey, Pierre-Yves; Le Moal, Sylvie; Bibes, Béatrice; Malizia, Giuseppe; Abgueguen, Pierre; Lifermann, François; Ninet, Jacques; Hatron, Pierre-Yves; Amoura, Zahir

2017-10-01

Monoclonal gammopathy-associated systemic capillary-leak syndrome, also known as Clarkson disease, is a rare condition characterized by recurrent life-threatening episodes of capillary hyperpermeability in the context of a monoclonal gammopathy. This study was conducted to better describe the clinical characteristics, natural history, and long-term outcome of monoclonal gammopathy-associated systemic capillary-leak syndrome. We conducted a cohort analysis of all patients included in the European Clarkson disease (EurêClark) registry between January 1997 and March 2016. From diagnosis to last follow-up, studied outcomes (eg, the frequency and severity of attacks, death, and evolution toward multiple myeloma) and the type of preventive treatments administered were monitored every 6 months. Sixty-nine patients (M/F sex ratio 1:1; mean ± SD age at disease onset 52 ± 12 years) were included in the study. All patients had monoclonal gammopathy of immunoglobulin G type, with kappa light chains in 47 (68%). Median (interquartile range) follow-up duration was 5.1 (2.5-9.7) years. Twenty-four patients (35%) died after 3.3 (0.9-8) years. Fifty-seven (86%) patients received at least one preventive treatment, including intravenous immunoglobulins (IVIg) n = 48 (73.8%), theophylline n = 22 (33.8%), terbutaline n = 22 (33.8%), and thalidomide n = 5 (7.7%). In the 65 patients with follow-up, 5- and 10-year survival rates were 78% (n = 35) and 69% (n = 17), respectively. Multivariate analysis found preventive treatment with IVIg (hazard ratio 0.27; 95% confidence interval, 0.10-0.70; P = .007) and terbutaline (hazard ratio 0.35; 95% confidence interval, 0.13-0.96; P = .041) to be independent predictors of mortality. We describe the largest cohort to date of patients with well-defined monoclonal gammopathy-associated systemic capillary-leak syndrome. Preventive treatment with IVIg was the strongest factor associated with survival, suggesting the use of IVIg as the first

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

PubMed

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.

Single-Molecule Detection in Micron-Sized Capillaries

NASA Astrophysics Data System (ADS)

Ball, David A.; Shen, Guoqing; Davis, Lloyd M.

2004-11-01

The detection of individual molecules in solution by laser-induced fluorescence is becoming an increasingly important tool for biophysics research and biotechnology applications. In a typical single-molecule detection (SMD) experiment, diffusion is the dominant mode of transport of fluorophores through the focused laser beam. In order to more rapidly process a large number of slowly diffusing bio-molecules for applications in pharmaceutical drug discovery, a flow can be introduced within a capillary. If the flow speed is sufficient, bio-molecules will be carried through the probe volume significantly faster than by diffusion alone. Here we discuss SMD near the tip of, and in, such micron-sized capillaries, with a high numerical-aperture microscope objective used for confocal-epi-illumination along the axis of the capillary. Problems such as molecular adsorption to the glass are also addressed.

Capillary red blood cell velocimetry by phase-resolved optical coherence tomography

NASA Astrophysics Data System (ADS)

Tang, Jianbo; Erdener, Sefik Evren; Fu, Buyin; Boas, David A.

2018-02-01

Quantitative measurement of blood flow velocity in capillaries is challenging due to their small size (around 5-10 μm), and the discontinuity and single-file feature of RBCs flowing in a capillary. In this work, we present a phase-resolved Optical Coherence Tomography (OCT) method for accurate measurement of the red blood cell (RBC) speed in cerebral capillaries. To account for the discontinuity of RBCs flowing in capillaries, we applied an M-mode scanning strategy that repeated A-scans at each scanning position for an extended time. As the capillary size is comparable to the OCT resolution size (3.5×3.5×3.5μm), we applied a high pass filter to remove the stationary signal component so that the phase information of the dynamic component (i.e. from the moving RBC) could be enhanced to provide an accurate estimate of the RBC axial speed. The phase-resolved OCT method accurately quantifies the axial velocity of RBC's from the phase shift of the dynamic component of the signal. We validated our measurements by RBC passage velocimetry using the signal magnitude of the same OCT time series data. These proposed method of capillary velocimetry proved to be a robust method of mapping capillary RBC speeds across the micro-vascular network.

Factors affecting the separation performance of proteins in capillary electrophoresis.

PubMed

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.

Intradural Extramedullary Capillary Hemangioma in the Upper Cervical Spine: First Report.

PubMed

Bouali, Sofiene; Maatar, Nidhal; Bouhoula, Asma; Abderrahmen, Khansa; Kallel, Jalel; Jemel, Hafedh

2016-08-01

The occurrence of intradural extramedullary capillary hemangiomas is exceedingly rare. To date, only 39 cases of intradural extramedullary capillary hemangiomas have been reported in the English literature, and all of these cases have been described at the lumbar and thoracic spinal levels. To our knowledge, this report is the first case of capillary hemangiomas of the cervical spine in the literature. In general, this entity is misdiagnosed preoperatively as a neoplasm. A 29-year-old man presented with neck pain and progressive gait disturbance, and was diagnosed with an intradural extramedullary capillary hemangioma in the cervical region. Although rare, our case demonstrates that capillary hemangioma should be considered in the differential diagnosis of intradural extramedullary tumor of the cervical spine. Copyright © 2016 Elsevier Inc. All rights reserved.

A method for integrating multiple components in a decision support system

Treesearch

Donald Nute; Walter D. Potter; Zhiyuan Cheng; Mayukh Dass; Astrid Glende; Frederick Maierv; Cy Routh; Hajime Uchiyama; Jin Wang; Sarah Witzig; Mark Twery; Peter Knopp; Scott Thomasma; H. Michael Rauscher

2005-01-01

We present a flexible, extensible method for integrating multiple tools into a single large decision support system (DSS) using a forest ecosystem management DSS (NED-2) as an example. In our approach, a rich ontology for the target domain is developed and implemented in the internal data model for the DSS. Semi-autonomous agents control external components and...

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

NASA Astrophysics Data System (ADS)

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.

PNEUMATIC MICROVALVE FOR ELECTROKINETIC SAMPLE PRECONCENTRATION AND CAPILLARY ELECTROPHORESIS INJECTION

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

Cong, Yongzheng; Rausch, Sarah J.; Geng, Tao

2014-10-27

Here we show that a closed pneumatic microvalve on a PDMS chip can serve as a semipermeable membrane under an applied potential, enabling current to pass through while blocking the passage of charged analytes. Enrichment of both anionic and cationic species has been demonstrated, and concentration factors of ~70 have been achieved in just 8 s. Once analytes are concentrated, the valve is briefly opened and the sample is hydrodynamically injected onto an integrated microchip or capillary electrophoresis (CE) column. In contrast to existing preconcentration approaches, the membrane-based method described here enables both rapid analyte concentration as well as highmore » resolution separations.« less

Standardization of the capillary electrophoresis procedures Capillarys® CDT and Minicap® CDT in comparison to the IFCC reference measurement procedure.

PubMed

Schellenberg, François; Humeau, Camille

2017-06-01

CDT is at present the most relevant routinely available biological marker of alcohol use and is widely used for screening and monitoring of patients. The lack of standardization leads to specific reference intervals for each procedure. The IFCC working group devoted to CDT demonstrated that the standardization is possible using calibrators assigned to the reference measurement procedure. In this study, we compare the capillary electrophoresis (CE) techniques Capillarys® CDT and Minicap® CDT (Sebia, Lisses, France) to the reference procedure before and after standardization in 126 samples covering the range of CDT measurement. Both capillary electrophoresis procedures show a high correlation (r=0,997) with the reference procedure and the concordance correlation coefficient evaluated according to Mc Bride is "almost perfect" (>0.997 for both CE procedures). The number of results with a relative difference higher than the acceptable difference limit is only 1 for Capillarys® CDT and 5 for Minicap® CDT. These results demonstrate the efficiency of the standardization of CDT measurements for both CE techniques from Sebia, achieved using calibrators assigned to the reference measurement procedure.

Light propagation in the micro-size capillary injected by high temperature liquid

NASA Astrophysics Data System (ADS)

Li, Yan-jun; Li, Edward; Xiao, Hai

2016-11-01

The high temperature liquid is injected into the micro-size capillary and its light propagation behavior is investigated. We focus on two different liquid pumping methods. The first method can pump the high temperature liquid tin into the micro-size capillary by using a high pressure difference system. After pumping, a single mode fiber (SMF) connected with the optical carrier based microwave interferometry (OCMI) system is used to measure different liquid tin levels in the micro-size capillary. The second method can pump the room temperature engine oil into the capillary by using a syringe pump. This method can avoid the air bubbles when the liquids are pumped into the capillary.

SPECTRAL DOMAIN VERSUS SWEPT SOURCE OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY OF THE RETINAL CAPILLARY PLEXUSES IN SICKLE CELL MACULOPATHY.

PubMed

Jung, Jesse J; Chen, Michael H; Frambach, Caroline R; Rofagha, Soraya; Lee, Scott S

2018-01-01

To compare the spectral domain and swept source optical coherence tomography angiography findings in two cases of sickle cell maculopathy. A 53-year-old man and a 24-year-old man both with sickle cell disease (hemoglobin SS) presented with no visual complaints; Humphrey visual field testing demonstrated asymptomatic paracentral scotomas that extended nasally in the involved eyes. Clinical examination and multimodal imaging including spectral domain and swept source optical coherence tomography, and spectral domain optical coherence tomography angiography and swept source optical coherence tomography angiography (Carl Zeiss Meditec Inc, Dublin, CA) were performed. Fundus examination of both patients revealed subtle thinning of the macula. En-face swept source optical coherence tomography confirmed the extent of the thinning correlating with the functional paracentral scotomas on Humphrey visual field. Swept source optical coherence tomography B-scan revealed multiple confluent areas of inner nuclear thinning and significant temporal retinal atrophy. En-face 6 × 6-mm spectral domain optical coherence tomography angiography of the macula demonstrated greater loss of the deep capillary plexus compared with the superficial capillary plexus. Swept source optical coherence tomography angiography 12 × 12-mm imaging captured the same macular findings and loss of both plexuses temporally outside the macula. In these two cases of sickle cell maculopathy, deep capillary plexus ischemia is more extensive within the macula, whereas both the superficial capillary plexus and deep capillary plexus are involved outside the macula likely due to the greater oxygen demands and watershed nature of these areas. Swept source optical coherence tomography angiography clearly demonstrates the angiographic extent of the disease correlating with the Humphrey visual field scotomas and confluent areas of inner nuclear atrophy.

Nonlinear multiplicative dendritic integration in neuron and network models

PubMed Central

Zhang, Danke; Li, Yuanqing; Rasch, Malte J.; Wu, Si

2013-01-01

Neurons receive inputs from thousands of synapses distributed across dendritic trees of complex morphology. It is known that dendritic integration of excitatory and inhibitory synapses can be highly non-linear in reality and can heavily depend on the exact location and spatial arrangement of inhibitory and excitatory synapses on the dendrite. Despite this known fact, most neuron models used in artificial neural networks today still only describe the voltage potential of a single somatic compartment and assume a simple linear summation of all individual synaptic inputs. We here suggest a new biophysical motivated derivation of a single compartment model that integrates the non-linear effects of shunting inhibition, where an inhibitory input on the route of an excitatory input to the soma cancels or “shunts” the excitatory potential. In particular, our integration of non-linear dendritic processing into the neuron model follows a simple multiplicative rule, suggested recently by experiments, and allows for strict mathematical treatment of network effects. Using our new formulation, we further devised a spiking network model where inhibitory neurons act as global shunting gates, and show that the network exhibits persistent activity in a low firing regime. PMID:23658543

Single-step enantioselective amino acid flux analysis by capillary electrophoresis using on-line sample preconcentration with chemical derivatization.

PubMed

Ptolemy, Adam S; Tran, Lara; Britz-McKibbin, Philip

2006-07-15

Capillary electrophoresis (CE) represents a versatile platform for integrating sample pretreatment with chemical analysis because of its ability to tune analyte electromigration and band dispersion properties in discontinuous electrolyte systems. In this article, a single-step method that combines on-line sample preconcentration with in-capillary chemical derivatization is developed for rapid, sensitive, and enantioselective analysis of micromolar levels of amino acids that lack intrinsic chromophores by CE with UV detection. Time-resolved electrophoretic studies revealed two distinct stages of amino acid band narrowing within the original long sample injection plug occurring both prior to and after in-capillary labeling via zone passing by ortho-phthalaldehyde/N-acetyl l-cysteine (OPA/NAC). This technique enabled direct analysis of d-amino acids in a 95% enantiomeric excess mixture with sub-micromolar detection limits and minimal sample handling, where the capillary functions as a preconcentrator, microreactor, and chiral selector. On-line sample preconcentration with chemical derivatization CE (SPCD-CE) was applied to study the enantioselective amino acid flux in Escherichia coli bacteria cultures, which demonstrated a unique l-Ala efflux into the extracellular medium. New strategies for high-throughput analyses of low-abundance metabolites are important for understanding fundamental physiological processes in bacteria required for screening the efficacy of new classes of antibiotics as well as altered metabolism in genetically modified mutant strains.

Capillary Hemangioma of the Thoracic Spinal Cord

PubMed Central

Chung, Sung-Kyun; Nam, Taek-Kyun; Park, Seung-Won

2010-01-01

Capillary hemangiomas are common soft tissue tumors on the skin or mucosa of the head and neck in the early childhood, but very rare in the neuraxis. A 47-year-old man presented with one month history of back pain on the lower thoracic area, radiating pain to both legs, and hypesthesia below T7 dermatome. Thoracic spine MRI showed 1×1.3×1.5 cm, well-defined intradural mass at T6-7 disc space level, which showed isointensity to spinal cord on T1, heterogeneous isointensity on T2-weighted images, and homogeneous strong enhancement. The patient underwent T6-7 total laminotomy, complete tumor removal and laminoplasty. Histologically, the mass showed a capsulated nodular lesion composed of capillary-sized vascular channels, which were tightly packed into nodules separated by fibrous septa. These features were consistent with capillary hemangioma. PMID:21082058

Optical coherence tomography angiography-based capillary velocimetry

NASA Astrophysics Data System (ADS)

Wang, Ruikang K.; Zhang, Qinqin; Li, Yuandong; Song, Shaozhen

2017-06-01

Challenge persists in the field of optical coherence tomography (OCT) when it is required to quantify capillary blood flow within tissue beds in vivo. We propose a useful approach to statistically estimate the mean capillary flow velocity using a model-based statistical method of eigendecomposition (ED) analysis of the complex OCT signals obtained with the OCT angiography (OCTA) scanning protocol. ED-based analysis is achieved by the covariance matrix of the ensemble complex OCT signals, upon which the eigenvalues and eigenvectors that represent the subsets of the signal makeup are calculated. From this analysis, the signals due to moving particles can be isolated by employing an adaptive regression filter to remove the eigencomponents that represent static tissue signals. The mean frequency (MF) of moving particles can be estimated by the first lag-one autocorrelation of the corresponding eigenvectors. Three important parameters are introduced, including the blood flow signal power representing the presence of blood flow (i.e., OCTA signals), the MF indicating the mean velocity of blood flow, and the frequency bandwidth describing the temporal flow heterogeneity within a scanned tissue volume. The proposed approach is tested using scattering phantoms, in which microfluidic channels are used to simulate the functional capillary vessels that are perfused with the scattering intralipid solution. The results indicate a linear relationship between the MF and mean flow velocity. In vivo animal experiments are also conducted by imaging mouse brain with distal middle cerebral artery ligation to test the capability of the method to image the changes in capillary flows in response to an ischemic insult, demonstrating the practical usefulness of the proposed method for providing important quantifiable information about capillary tissue beds in the investigations of neurological conditions in vivo.

Microscopic video observation of capillary vessel systems using diffuse back lighting

NASA Astrophysics Data System (ADS)

Sakai, Minako; Arai, Hiroki; Iwai, Toshiaki

2017-04-01

We have been developing a simple and practical video microscopy system based on absorption spectra of biological substance to perform spectroscopic observation of living tissues. The diffuse backlighting effect is actively used in the developed system, which is generated by multiple light scattering in the tissue. It is demonstrated that the light specularly reflected from the skin surface can be completely suppressed in the microscopic observation and the biological activity of the capillary vessel systems distributed under the skin can be successfully observed. As a result, we can confirm the effectiveness of the video microscopy system using diffuse backlighting and the applicability of our developed system.

Integrative Analysis of Prognosis Data on Multiple Cancer Subtypes

PubMed Central

Liu, Jin; Huang, Jian; Zhang, Yawei; Lan, Qing; Rothman, Nathaniel; Zheng, Tongzhang; Ma, Shuangge

2014-01-01

Summary In cancer research, profiling studies have been extensively conducted, searching for genes/SNPs associated with prognosis. Cancer is diverse. Examining the similarity and difference in the genetic basis of multiple subtypes of the same cancer can lead to a better understanding of their connections and distinctions. Classic meta-analysis methods analyze each subtype separately and then compare analysis results across subtypes. Integrative analysis methods, in contrast, analyze the raw data on multiple subtypes simultaneously and can outperform meta-analysis methods. In this study, prognosis data on multiple subtypes of the same cancer are analyzed. An AFT (accelerated failure time) model is adopted to describe survival. The genetic basis of multiple subtypes is described using the heterogeneity model, which allows a gene/SNP to be associated with prognosis of some subtypes but not others. A compound penalization method is developed to identify genes that contain important SNPs associated with prognosis. The proposed method has an intuitive formulation and is realized using an iterative algorithm. Asymptotic properties are rigorously established. Simulation shows that the proposed method has satisfactory performance and outperforms a penalization-based meta-analysis method and a regularized thresholding method. An NHL (non-Hodgkin lymphoma) prognosis study with SNP measurements is analyzed. Genes associated with the three major subtypes, namely DLBCL, FL, and CLL/SLL, are identified. The proposed method identifies genes that are different from alternatives and have important implications and satisfactory prediction performance. PMID:24766212

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

PubMed

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

2013-09-01

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

Noninvasive imaging of human foveal capillary network using dual-conjugate adaptive optics.

PubMed

Popovic, Zoran; Knutsson, Per; Thaung, Jörgen; Owner-Petersen, Mette; Sjöstrand, Johan

2011-04-22

To demonstrate noninvasive imaging of human foveal capillary networks with a high-resolution, wide-field, dual-conjugate adaptive optics (DCAO) imaging instrument. The foveal capillary networks of five healthy subjects with no previous history of ocular or neurologic disease or surgery were imaged with a novel high-resolution, wide-field DCAO instrument. The foveal avascular zone (FAZ) in each image was defined using a manual procedure. An automated algorithm based on publicly available and custom-written software was used to identify vessels and extract morphologic FAZ and vessel parameters. Capillary densities were calculated in two annular regions of interest (ROIs) outside the FAZ (500 μm and 750 μm outer radius from the foveal center) and in the superior, inferior, temporal, and nasal quadrants within the two ROIs. Mean FAZ area was 0.302 ± 0.100 mm(2), and mean capillary density (length/area) in the inner ROI was 38.0 ± 4.0 mm(-1) and 36.4 ± 4.0 mm(-1) in the outer ROI. The difference in ROI capillary density was not significant. There was no significant difference in quadrant capillary density within the two ROIs or between quadrants irrespective of ROI. The authors have demonstrated a technique for noninvasive imaging and semiautomated detection and analysis of foveal capillaries. In comparison with other studies, their method yielded lower capillary densities than histology but similar results to the current clinical gold standard, fluorescein angiography. The increased field of view of the DCAO instrument opens up new possibilities for high-resolution noninvasive clinical imaging of foveal capillaries.

Delayed post-traumatic capillary haemangioma of the spine.

PubMed

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.

Improved Sensitivity of Spectroscopic Quantification of Stable Isotope Content Using Capillary Absorption Spectroscopy

NASA Astrophysics Data System (ADS)

Moran, J.; Wilcox Freeburg, E.; Kriesel, J.; Linley, T. J.; Kelly, J.; Coleman, M. L.; Christensen, L. E.; Vance, S.

2016-12-01

Spectroscopy-based platforms have recently risen to the forefront for making stable isotope measurements of methane, carbon dioxide, water, or other analytes. These spectroscopy systems can be relatively straightforward to operate (versus a mass spectrometry platform), largely relieve the analyst of mass interference artifacts, and many can be used in the field. Despite these significant advantages, however, existing spectroscopy techniques suffer from a lack of measurement sensitivity that can ultimately limit select applications including spatially resolved and compound-specific measurements. Here we present a capillary absorption spectroscopy (CAS) system that is designed to mitigate sensitivity issues in spectroscopy-based stable isotope evaluation. The system uses mid-wave infrared excitation generated from a continuous wave quantum cascade laser. Importantly, the sample `chamber' is a flexible capillary with a total volume of less than one cc. Proprietary coatings on the internal surface of the fiber improve optical performance, guiding the light to a detector and facilitating high levels of interaction between the laser beam and gaseous analytes. We present data demonstrating that a tapered hollow fiber cell, with an internal diameter that broadens toward the detector, reduces optical feedback to further improve measurement sensitivity. Sensitivity of current hollow fiber / CAS systems enable measurements of only 10's of picomoles CO2 while theoretical improvements should enable measurements of as little as 10's of femtomoles. Continued optimization of sample introduction and improvements to optical feedback are being explored. Software is being designed to provide rapid integration of data and generation of processed isotope measurements using a graphical user interface. Taken together, the sensitivity improvements of the CAS system under development could, when coupled to a laser ablation sampling device, enable up to 2 µm spatial resolution (roughly the

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

NASA Astrophysics Data System (ADS)

Stoytschew, V.; Schulte-Borchers, M.; Božičević Mihalića, Iva; Perez, R. D.

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.

Nonlinear Dynamics of Formation of Drops of Non-Newtonian Liquids from Capillaries: Satellite Formation and Flow Transitions

NASA Astrophysics Data System (ADS)

Yildirim, Ozgur E.; Basaran, Osman A.

1999-11-01

Drop formation from capillaries, and the often undesired phenomenon of satellite generation, play a central role in diverse applications including ink-jet printing, biochip processors, and spray coating, where the working fluid is usually non-Newtonian. Although some work has been done in related areas, the phenomenon of formation of drops of non--Newtonian fluids from capillaries has remained largely unexplored. Here a theoretical approach is adopted to study the dripping of axisymmetric drops of non--Newtonian liquids from capillaries. The constitutive equation used accounts for both shear thinning and strain hardening. First, regular perturbation theory is utilized to reduce the spatial dimension of the governing equations to one. The computations rely on Galerkin/finite element analysis with adaptive finite differencing for time integration. The dynamics are followed beyond the first breakup to investigate conditions for occurrence of satellites. Effect of increasing flow rate is also studied to uncover transitions that occur as one moves from a regime of periodic drop formation to one of jetting.

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

DOE PAGES

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

2017-02-09

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

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

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

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

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

Capillary-induced crack healing between surfaces of nanoscale roughness.

PubMed

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.

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

PubMed Central

Glancy, Brian; Hsu, Li-Yueh; Dao, Lam; Bakalar, Matthew; French, Stephanie; Chess, David J.; Taylor, Joni L.; Picard, Martin; Aponte, Angel; Daniels, Mathew P.; Esfahani, Shervin; Cushman, Samuel; Balaban, Robert S.

2013-01-01

Objective To provide insight into mitochondrial function in vivo, we evaluated the 3D spatial relationship between capillaries, mitochondria, and muscle fibers in live mice. Methods 3D volumes of in vivo murine Tibialis anterior muscles were imaged by multi-photon microscopy (MPM). Muscle fiber type, mitochondrial distribution, number of capillaries, and capillary-to-fiber contact were assessed. The role of myoglobin-facilitated diffusion was examined in myoglobin knockout mice. Distribution of GLUT4 was also evaluated in the context of the capillary and mitochondrial network. Results MPM revealed that 43.6 ± 3.3% of oxidative fiber capillaries had ≥ 50% of their circumference embedded in a groove in the sarcolemma, in vivo. Embedded capillaries were tightly associated with dense mitochondrial populations lateral to capillary grooves and nearly absent below the groove. Mitochondrial distribution, number of embedded capillaries, and capillary-to-fiber contact were proportional to fiber oxidative capacity and unaffected by myoglobin knockout. GLUT4 did not preferentially localize to embedded capillaries. Conclusions Embedding capillaries in the sarcolemma may provide a regulatory mechanism to optimize delivery of oxygen to heterogeneous groups of muscle fibers. We hypothesize that mitochondria locate to paravascular regions due to myofibril voids created by embedded capillaries, not to enhance the delivery of oxygen to the mitochondria. PMID:25279425

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

PubMed

Gurina, O Iu; Karaganov, Ia L

1984-08-01

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

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

NASA Astrophysics Data System (ADS)

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

2013-04-01

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.

Integrative metabolomics for characterizing unknown low-abundance metabolites by capillary electrophoresis-mass spectrometry with computer simulations.

PubMed

Lee, Richard; Ptolemy, Adam S; Niewczas, Liliana; Britz-McKibbin, Philip

2007-01-15

Characterization of unknown low-abundance metabolites in biological samples is one the most significant challenges in metabolomic research. In this report, an integrative strategy based on capillary electrophoresis-electrospray ionization-ion trap mass spectrometry (CE-ESI-ITMS) with computer simulations is examined as a multiplexed approach for studying the selective nutrient uptake behavior of E. coli within a complex broth medium. On-line sample preconcentration with desalting by CE-ESI-ITMS was performed directly without off-line sample pretreatment in order to improve detector sensitivity over 50-fold for cationic metabolites with nanomolar detection limits. The migration behavior of charged metabolites were also modeled in CE as a qualitative tool to support MS characterization based on two fundamental analyte physicochemical properties, namely, absolute mobility (muo) and acid dissociation constant (pKa). Computer simulations using Simul 5.0 were used to better understand the dynamics of analyte electromigration, as well as aiding de novo identification of unknown nutrients. There was excellent agreement between computer-simulated and experimental electropherograms for several classes of cationic metabolites as reflected by their relative migration times with an average error of <2.0%. Our studies revealed differential uptake of specific amino acids and nucleoside nutrients associated with distinct stages of bacterial growth. Herein, we demonstrate that CE can serve as an effective preconcentrator, desalter, and separator prior to ESI-MS, while providing additional qualitative information for unambiguous identification among isobaric and isomeric metabolites. The proposed strategy is particularly relevant for characterizing unknown yet biologically relevant metabolites that are not readily synthesized or commercially available.

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

PubMed Central

Mechref, Yehia

2012-01-01

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

Finite volume solution for two-phase flow in a straight capillary

NASA Astrophysics Data System (ADS)

Yelkhovsky, Alexander; Pinczewski, W. Val

2018-04-01

The problem of two-phase flow in straight capillaries of polygonal cross section displays many of the dynamic characteristics of rapid interfacial motions associated with pore-scale displacements in porous media. Fluid inertia is known to be important in these displacements but is usually ignored in network models commonly used to predict macroscopic flow properties. This study presents a numerical model for two-phase flow which describes the spatial and temporal evolution of the interface between the fluids. The model is based on an averaged Navier-Stokes equation and is shown to be successful in predicting the complex dynamics of both capillary rise in round capillaries and imbibition along the corners of polygonal capillaries. The model can form the basis for more realistic network models which capture the effect of capillary, viscous, and inertial forces on pore-scale interfacial dynamics and consequent macroscopic flow properties.

Compound Capillary Flows in Complex Containers: Drop Tower Test Results

NASA Astrophysics Data System (ADS)

Bolleddula, Daniel A.; Chen, Yongkang; Semerjian, Ben; Tavan, Noël; Weislogel, Mark M.

2010-10-01

Drop towers continue to provide unique capabilities to investigate capillary flow phenomena relevant to terrestrial and space-based capillary fluidics applications. In this study certain `capillary rise' flows and the value of drop tower experimental investigations are briefly reviewed. A new analytic solution for flows along planar interior edges is presented. A selection of test cell geometries are then discussed where compound capillary flows occur spontaneously and simultaneously over local and global length scales. Sample experimental results are provided. Tertiary experiments on a family of asymmetric geometries that isolate the global component of such flows are then presented along with a qualitative analysis that may be used to either avoid or exploit such flows. The latter may also serve as a design tool with which to assess the impact of inadvertent container asymmetry.

Dynamical clustering of red blood cells in capillary vessels.

PubMed

Boryczko, Krzysztof; Dzwinel, Witold; Yuen, David A

2003-02-01

We have modeled the dynamics of a 3-D system consisting of red blood cells (RBCs), plasma and capillary walls using a discrete-particle approach. The blood cells and capillary walls are composed of a mesh of particles interacting with harmonic forces between nearest neighbors. We employ classical mechanics to mimic the elastic properties of RBCs with a biconcave disk composed of a mesh of spring-like particles. The fluid particle method allows for modeling the plasma as a particle ensemble, where each particle represents a collective unit of fluid, which is defined by its mass, moment of inertia, translational and angular momenta. Realistic behavior of blood cells is modeled by considering RBCs and plasma flowing through capillaries of various shapes. Three types of vessels are employed: a pipe with a choking point, a curved vessel and bifurcating capillaries. There is a strong tendency to produce RBC clusters in capillaries. The choking points and other irregularities in geometry influence both the flow and RBC shapes, considerably increasing the clotting effect. We also discuss other clotting factors coming from the physical properties of blood, such as the viscosity of the plasma and the elasticity of the RBCs. Modeling has been carried out with adequate resolution by using 1 to 10 million particles. Discrete particle simulations open a new pathway for modeling the dynamics of complex, viscoelastic fluids at the microscale, where both liquid and solid phases are treated with discrete particles. Figure A snapshot from fluid particle simulation of RBCs flowing along a curved capillary. The red color corresponds to the highest velocity. We can observe aggregation of RBCs at places with the most stagnant plasma flow.

Molecular transport through capillaries made with atomic-scale precision

NASA Astrophysics Data System (ADS)

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

2016-10-01

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

Capillary Hemangioma of Thoracic Spinal Cord: PET/CT and MR Findings.

PubMed

Shen, Guohua; Su, Minggang; Zhao, Junyi; Liu, Bin; Kuang, Anren

2017-05-01

Capillary hemangiomas are frequently encountered superficially in the cutaneous, subcutaneous, or mucosal tissues during the childhood and early adulthood, but the occurrence of spinal intradural capillary hemangioma is relatively rare. Herein, we report a case with capillary hemangioma of the thoracic spine. MR and PET/CT features of this lesion are presented, and awareness of this entity may help differentiate it from other spinal intradural tumors.

Optimization of x-ray capillary optics for mammography

NASA Astrophysics Data System (ADS)

Ross, Richard E.; Bradford, Carla D.; Peppler, Walter W.

2002-05-01

The purpose of this study is to develop a full-field digital mammography system utilizing capillary optics. Specific aims are to identify optic properties that affect image quality and to optimize those properties in the design of a multi-element capillary array. It has been shown that polycapillary optics significantly improve mammographic image quality through increased resolution and reduced x-ray scatter. For practical clinical application much larger multi-element optics will be required. This study quantified the contributing factors to the multi-element optic MTF and investigated methods to determine optimal parameters for a practical design. Individual and a prototype multi-element array of linearly tapered optics with a common focal point were investigated. A conventional (MO/MO) mammography tube and computed radiography system were used. The system and optic MTF were measured using the angled slit method with a slit camera (10 micron slit). MTF measurements were performed with both stationary and scanned optics. Contributions to MTF included: distortion within individual optics, misalignment between optics, capillary channel size, and vibration. Measurement techniques used to identify and quantify the contributions to optic MTF included a phantom chosen specifically for polycapillary optics. This phantom provided a method for assessing the coherence among capillaries within an optic as well as the relative alignment of the optics within the array. In addition, modifications to the scanning procedure allowed for the isolation and quantification of several contributors to the system MTF. Specifically, measurements were made using a stationary optic, a scanning optic, and an optic placed at multiple locations within the imaged field of view. These techniques yielded the optic MTF, the degradation of MTF due to loss of coherence within the optic, and the degradation of MTF due to vibration of the scanning mechanism. Distortion within individual optics was

Mechanisms in the loss of capillaries in systemic sclerosis: angiogenesis versus vasculogenesis

PubMed Central

Manetti, Mirko; Guiducci, Serena; Ibba-Manneschi, Lidia; Matucci-Cerinic, Marco

2010-01-01

Abstract Systemic sclerosis (SSc, scleroderma) is a chronic, multisystem connective tissue disorder affecting the skin and various internal organs. Although the disease is characterized by a triad of widespread microangiopathy, fibrosis and autoimmunity, increasing evidence indicates that vascular damage is a primary event in the pathogenesis of SSc. The progressive vascular injury includes persistent endothelial cell activation/damage and apoptosis, intimal thickening, delamination, vessel narrowing and obliteration. These profound vascular changes lead to vascular tone dysfunction and reduced capillary blood flow, with consequent tissue ischemia and severe clinical manifestations, such as digital ulceration or amputation, pulmonary arterial hypertension and scleroderma renal crisis. The resulting tissue hypoxia induces complex cellular and molecular mechanisms in the attempt to recover endothelial cell function and tissue perfusion. Nevertheless, in SSc patients there is no evidence of significant angiogenesis and the disease evolves towards chronic tissue ischemia, with progressive and irreversible structural changes in multiple vascular beds culminating in the loss of capillaries. A severe imbalance between pro-angiogenic and angiostatic factors may also lead to impaired angiogenic response during SSc. Besides insufficient angiogenesis, defective vasculogenesis with altered numbers and functional defects of bone marrow-derived endothelial progenitor cells may contribute to the vascular pathogenesis of SSc. The purpose of this article is to review the contribution of recent studies to the understanding of the complex mechanisms of impaired vascular repair in SSc. Indeed, understanding the pathophysiology of SSc-associated vascular disease may be the key in dissecting the disease pathogenesis and developing novel therapies. Either angiogenic or vasculogenic mechanisms may potentially become in the future the target of therapeutic strategies to promote capillary

Capillary-Driven Flow in Liquid Filaments Connecting Orthogonal Channels

NASA Technical Reports Server (NTRS)

Allen, Jeffrey S.

2005-01-01

Capillary phenomena plays an important role in the management of product water in PEM fuel cells because of the length scales associated with the porous layers and the gas flow channels. The distribution of liquid water within the network of gas flow channels can be dramatically altered by capillary flow. We experimentally demonstrate the rapid movement of significant volumes of liquid via capillarity through thin liquid films which connect orthogonal channels. The microfluidic experiments discussed provide a good benchmark against which the proper modeling of capillarity by computational models may be tested. The effect of surface wettability, as expressed through the contact angle, on capillary flow will also be discussed.

Repeatability of intravital capillaroscopic measurement of capillary density.

PubMed

Lamah, M; Chaudhry, H; Mortimer, P S; Dormandy, J A

1996-01-01

The reliability of intravital capillaroscopy for determining capillary density (CD) of skin has been questioned because it depends upon the variability of the measuring process and subjective interpretation of data as well as the intrinsic heterogeneity of capillary spacing. The aim of this study was to assess the repeatability of a standardised method for measuring CD of the skin of the dorsum of foot. In each of 30 subjects (10 controls and 20 patients with peripheral vascular disease), the foot was systematically mapped by examining 20 sites on the dorsum of foot and 2 sites on each toe, using white light (native) videomicroscopy at 40 x magnification. Off-line analysis of videoprints was then undertaken to determine CD at each site, by counting capillaries within areas of acceptable photographic quality only, having first defined the criteria for counting capillaries. The mean values were then calculated and taken to represent the CD of the foot or toes. Repeatability of the measuring equipment was first assessed by noting the presence or absence of each corresponding capillary in 2 prints, taken at intervals of hours or days (in 10 subjects) or months (in 2 patients), of an identical area of skin which was marked by a microtattoo on the first occasion. On average, 95% of corresponding capillaries were identified in both prints (from controls and patients), thus implying little intrinsic temporal variation of capillary anatomy as well as excellent repeatability of the measuring equipment. Repeatability of data analysis was assessed by the same observer reading the same 20 prints in a blinded manner on three separate occasions (intraobserver repeatability), and 2 observers reading the same 24 prints (interobserver repeatability). The mean coefficient of intraobserver variation of CD estimate was 5.6% and the interobserver correlation coefficient was 0.94. Finally, overall repeatability of the method was assessed by repeating the procedure on a subsequent

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

PubMed

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.

Capillary waves with surface viscosity

NASA Astrophysics Data System (ADS)

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.

Use of Plastic Capillaries for Macromolecular Crystallization

NASA Technical Reports Server (NTRS)

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.

Capillary spreading of contact line over a sinking sphere

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

Kim, Seong Jin; Fezzaa, Kamel; An, Jim

The contact line dynamics over a sinking solid sphere are investigated in comparison with classical spreading theories. Experimentally, high-speed imaging systems with optical light or x-ray illumination are employed to accurately measure the spreading motion and dynamic contact angle of the contact line. Millimetric spheres are controlled to descend with a constant speed ranging from 7.3 × 10-5 to 0.79 m/s. We observed three different spreading stages over a sinking sphere, which depends on the contact line velocity and contact angle. These stages consistently showed the characteristics of capillarity-driven spreading as the contact line spreads faster with a higher contactmore » angle. The contact line velocity is observed to follow a classical capillary-viscous model at a high Ohnesorge number (> 0.02). For the cases with a relatively low Ohnesorge number (< 0.02), the contact line velocity is significantly lower than the speed predicted by the capillary-viscous balance. This indicates the existence of an additional opposing force (inertia) for a decreasing Ohnesorge number. The capillary-inertial balance is only observed at the very beginning of the capillary rise, in which the maximum velocity is independent of the sphere’s sinking speed. Additionally, we observed the linear relation between the contact line velocity and the sphere sinking speed during the second stage, which represents capillary adjustment by dynamic contact angle.« less

Natural Attenuation of Nonvolatile Contaminants in the Capillary Fringe.

PubMed

Kurt, Zohre; Mack, E Erin; Spain, Jim C

2016-09-20

When anoxic polluted groundwater encounters the overlying vadose zone an oxic/anoxic interface is created, often near the capillary fringe. Biodegradation of volatile contaminants in the capillary fringe can prevent vapor migration. In contrast, the biodegradation of nonvolatile contaminants in the vadose zone has received comparatively little attention. Nonvolatile compounds do not cause vapor intrusion, but they still move with the groundwater and are major contaminants. Aniline (AN) and diphenylamine (DPA) are examples of toxic nonvolatile contaminants found often at dye and munitions manufacturing sites. In this study, we tested the hypothesis that bacteria can aerobically biodegrade AN and DPA in the capillary fringe and decrease the contaminant concentrations in the anoxic plume beneath the vadose zone. Laboratory multiport columns that represented the unsaturated zone were used to evaluate degradation of AN or DPA in contaminated water. The biodegradation fluxes of the contaminants were estimated to be 113 ± 26 mg AN·m(-2)·h(-1) and 76 ± 18 mg DPA·m(-2)·h(-1) in the presence of bacteria known to degrade AN and DPA. Oxygen and contaminant profiles along with enumeration of bacterial populations indicated that most of the biodegradation took place within the lower part of the capillary fringe. The results indicate that bacteria capable of contaminant biodegradation in the capillary fringe can create a sink for nonvolatile contaminants.

Silver nanoparticle-doped zirconia capillaries for enhanced bacterial filtration.

PubMed

Wehling, Julia; Köser, Jan; Lindner, Patrick; Lüder, Christian; Beutel, Sascha; Kroll, Stephen; Rezwan, Kurosch

2015-03-01

Membrane clogging and biofilm formation are the most serious problems during water filtration. Silver nanoparticle (Agnano) coatings on filtration membranes can prevent bacterial adhesion and the initiation of biofilm formation. In this study, Agnano are immobilized via direct reduction on porous zirconia capillary membranes to generate a nanocomposite material combining the advantages of ceramics being chemically, thermally and mechanically stable with nanosilver, an efficient broadband bactericide for water decontamination. The filtration of bacterial suspensions of the fecal contaminant Escherichia coli reveals highly efficient bacterial retention capacities of the capillaries of 8 log reduction values, fulfilling the requirements on safe drinking water according to the U.S. Environmental Protection Agency. Maximum bacterial loading capacities of the capillary membranes are determined to be 3×10(9)bacterialcells/750mm(2) capillary surface until back flushing is recommendable. The immobilized Agnano remain accessible and exhibit strong bactericidal properties by killing retained bacteria up to maximum bacterial loads of 6×10(8)bacterialcells/750mm(2) capillary surface and the regenerated membranes regain filtration efficiencies of 95-100%. Silver release is moderate as only 0.8% of the initial silver loading is leached during a three-day filtration experiment leading to average silver contaminant levels of 100μg/L. Copyright © 2014 Elsevier B.V. All rights reserved.

Multiple-source spatial data fusion and integration research in the region unified planning management information system

NASA Astrophysics Data System (ADS)

Liu, Zhijun; Zhang, Liangpei; Liu, Zhenmin; Jiao, Hongbo; Chen, Liqun

2008-12-01

In order to manage the internal resources of Gulf of Tonkin and integrate multiple-source spatial data, the establishment of region unified plan management system is needed. The data fusion and the integrated research should be carried on because there are some difficulties in the course of the system's establishment. For example, kinds of planning and the project data format are different, and data criterion is not unified. Besides, the time state property is strong, and spatial reference is inconsistent, etc. In this article the ARCGIS ENGINE is introduced as the developing platform, key technologies are researched, such as multiple-source data transformation and fusion, remote sensing data and DEM fusion and integrated, plan and project data integration, and so on. Practice shows that the system improves the working efficiency of Guangxi Gulf of Tonkin Economic Zone Management Committee significantly and promotes planning construction work of the economic zone remarkably.

A Zero Dimensional Time-Dependent Model of High-Pressure Ablative Capillary Discharge (Preprint)

DTIC Science & Technology

2008-06-01

comprehensive model of capillary discharge is important to understand the physics and engineering aspects of the capillary discharge thruster. A schematic...investigators since the mid-1980s see 1-11 and references therein, satisfy both of these conditions well. These studies investigated the dynamics of high...is a comprehensive description of the radiative heat transfer in the capillary discharge. It is worth noting that in other types of capillary

Van der waals forces on thin liquid films in capillary tubes

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

Herdt, G.C.; Swanson, L.W.

1993-10-01

A theory of the van der Waals attraction between a thin liquid films and a capillary tube is presented assuming the presence of a vapor-liquid interface. The model is based on the surface mode analysis method of van Kampen et al. Values for the van der Waals interaction energy per unit area were calculated for liquid films of pentane on a gold substrate assuming a thin liquid film. Results indicate that the effect of capillary curvature on the van der Waals interaction increases as the ratio of the liquid film thickness to the capillary radius is increased. This trend ismore » consistent with predictions based on the Hamaker theory. Deviations from results based on the Hamaker theory are easily explained in terms of retardation of the van der Waals interaction. Because the effect of capillary curvature increases in the regime where retardation effects become important, curvature effects constitute a small correction to the van der Waals forces in a capillary tube.« less

Sparse Group Penalized Integrative Analysis of Multiple Cancer Prognosis Datasets

PubMed Central

Liu, Jin; Huang, Jian; Xie, Yang; Ma, Shuangge

2014-01-01

SUMMARY In cancer research, high-throughput profiling studies have been extensively conducted, searching for markers associated with prognosis. Because of the “large d, small n” characteristic, results generated from the analysis of a single dataset can be unsatisfactory. Recent studies have shown that integrative analysis, which simultaneously analyzes multiple datasets, can be more effective than single-dataset analysis and classic meta-analysis. In most of existing integrative analysis, the homogeneity model has been assumed, which postulates that different datasets share the same set of markers. Several approaches have been designed to reinforce this assumption. In practice, different datasets may differ in terms of patient selection criteria, profiling techniques, and many other aspects. Such differences may make the homogeneity model too restricted. In this study, we assume the heterogeneity model, under which different datasets are allowed to have different sets of markers. With multiple cancer prognosis datasets, we adopt the AFT (accelerated failure time) model to describe survival. This model may have the lowest computational cost among popular semiparametric survival models. For marker selection, we adopt a sparse group MCP (minimax concave penalty) approach. This approach has an intuitive formulation and can be computed using an effective group coordinate descent algorithm. Simulation study shows that it outperforms the existing approaches under both the homogeneity and heterogeneity models. Data analysis further demonstrates the merit of heterogeneity model and proposed approach. PMID:23938111

Effect of hypothermic pulmonary artery flushing on capillary filtration coefficient.

PubMed

Andrade, R S; Wangensteen, O D; Jo, J K; Tsai, M Y; Bolman, R M

2000-07-27

We previously demonstrated that surfactant dilution and inhibition occur immediately after pulmonary artery flushing with hypothermic modified Euro-Collins solution. Consequently, we speculated that increased capillary permeability contributed to these surfactant changes. To test this hypothesis, we evaluated the effects of hypothermic pulmonary artery flushing on the pulmonary capillary filtration coefficient (Kfc), and additionally performed a biochemical analysis of surfactant. We used a murine isolated, perfused lung model to measure the pulmonary capillary filtration coefficient and hemodynamic parameters, to determine the wet to dry weight ratio, and to evaluate surfactant by biochemical analysis of lung lavage fluid. We defined three study groups. In group I (controls), we harvested lungs without hypothermic pulmonary artery flushing, and measured Kfc immediately. In group II (in situ flush), we harvested lungs after hypothermic pulmonary artery flushing with modified Euro-Collins solution, and then measured Kfc. Experiments in groups I and II were designed to evaluate persistent changes in Kfc after pulmonary artery flushing. In group III (ex vivo flush), we flushed lungs ex vivo to evaluate transient changes in Kfc during hypothermic pulmonary artery flushing. Groups I and II did not differ significantly in capillary filtration coefficient and hemodynamics. Group II showed significant alterations on biochemical surfactant analysis and a significant increase in wet-to-dry weight ratio, when compared with group I. In group III, we observed a significant transient increase in capillary filtration coefficient during pulmonary artery flushing. Hypothermic pulmonary artery flushing transiently increases the capillary filtration coefficient, leads to an increase in the wet to dry weight ratio, and induces biochemical surfactant changes. These findings could be explained by the effects of hypothermic modified Euro-Collins solution on pulmonary capillary

Capillary pumping independent of the liquid surface energy and viscosity

NASA Astrophysics Data System (ADS)

Guo, Weijin; Hansson, Jonas; van der Wijngaart, Wouter

2018-03-01

Capillary pumping is an attractive means of liquid actuation because it is a passive mechanism, i.e., it does not rely on an external energy supply during operation. The capillary flow rate generally depends on the liquid sample viscosity and surface energy. This poses a problem for capillary-driven systems that rely on a predictable flow rate and for which the sample viscosity or surface energy are not precisely known. Here, we introduce the capillary pumping of sample liquids with a flow rate that is constant in time and independent of the sample viscosity and sample surface energy. These features are enabled by a design in which a well-characterized pump liquid is capillarily imbibed into the downstream section of the pump and thereby pulls the unknown sample liquid into the upstream pump section. The downstream pump geometry is designed to exert a Laplace pressure and fluidic resistance that are substantially larger than those exerted by the upstream pump geometry on the sample liquid. Hence, the influence of the unknown sample liquid on the flow rate is negligible. We experimentally tested pumps of the new design with a variety of sample liquids, including water, different samples of whole blood, different samples of urine, isopropanol, mineral oil, and glycerol. The capillary filling speeds of these liquids vary by more than a factor 1000 when imbibed to a standard constant cross-section glass capillary. In our new pump design, 20 filling tests involving these liquid samples with vastly different properties resulted in a constant volumetric flow rate in the range of 20.96-24.76 μL/min. We expect this novel capillary design to have immediate applications in lab-on-a-chip systems and diagnostic devices.

Capillary liquid chromatography-microchip atmospheric pressure chemical ionization-mass spectrometry.

PubMed

Ostman, Pekka; Jäntti, Sirkku; Grigoras, Kestas; Saarela, Ville; Ketola, Raimo A; Franssila, Sami; Kotiaho, Tapio; Kostiainen, Risto

2006-07-01

A miniaturized nebulizer chip for capillary liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry (capillary LC-microchip APCI-MS) is presented. The APCI chip consists of two wafers, a silicon wafer and a Pyrex glass wafer. The silicon wafer has a DRIE etched through-wafer nebulizer gas inlet, an edge capillary insertion channel, a stopper, a vaporizer channel and a nozzle. The platinum heater electrode and pads for electrical connection were patterned on to the Pyrex glass wafer. The two wafers were joined by anodic bonding, creating a microchip version of an APCI-source. The sample inlet capillary from an LC column is directly connected to the vaporizer channel of the APCI chip. The etched nozzle in the microchip forms a narrow sample plume, which is ionized by an external corona needle, and the formed ions are analyzed by a mass spectrometer. The nebulizer chip enables for the first time the use of low flow rate separation techniques with APCI-MS. The performance of capillary LC-microchip APCI-MS was tested with selected neurosteroids. The capillary LC-microchip APCI-MS provides quantitative repeatability and good linearity. The limits of detection (LOD) with a signal-to-noise ratio (S/N) of 3 in MS/MS mode for the selected neurosteroids were 20-1000 fmol (10-500 nmol l(-1)). LODs (S/N = 3) with commercial macro APCI with the same compounds using the same MS were about 10 times higher. Fast heat transfer allows the use of the optimized temperature for each compound during an LC run. The microchip APCI-source provides a convenient and easy method to combine capillary LC to any API-MS equipped with an APCI source. The advantages and potentials of the microchip APCI also make it a very attractive interface in microfluidic APCI-MS.

Total integrated slidable and valveless solid phase extraction-polymerase chain reaction-capillary electrophoresis microdevice for mini Y chromosome short tandem repeat genotyping.

PubMed

Kim, Yong Tae; Lee, Dohwan; Heo, Hyun Young; Sim, Jeong Eun; Woo, Kwang Man; Kim, Do Hyun; Im, Sung Gap; Seo, Tae Seok

2016-04-15

A fully integrated slidable and valveless microsystem, which performs solid phase DNA extraction (SPE), micro-polymerase chain reaction (μPCR) and micro-capillary electrophoresis (μCE) coupled with a portable genetic analyser, has been developed for forensic genotyping. The use of a slidable chip, in which a 1 μL-volume of the PCR chamber was patterned at the center, does not necessitate any microvalves and tubing systems for fluidic control. The functional micro-units of SPE, μPCR, and μCE were fabricated on a single glass wafer by conventional photolithography, and the integrated microdevice consists of three layers: from top to bottom, a slidable chip, a channel wafer in which a SPE chamber, a mixing microchannel, and a CE microchannel were fabricated, and a Ti/Pt resistance temperature detector (RTD) wafer. The channel glass wafer and the RTD glass wafer were thermally bonded, and the slidable chip was placed on the designated functional unit. The entire process from the DNA extraction using whole human blood sample to identification of target Y chromosomal short tandem repeat (STR) loci was serially carried out with simply sliding the slidable chamber from one to another functional unit. Monoplex and multiplex detection of amelogenin and mini Y STR loci were successfully analysed on the integrated slidable SPE-μPCR-μCE microdevice by using 1 μL whole human blood within 60 min. The proposed advanced genetic analysis microsystem is capable of point-of-care DNA testing with sample-in-answer-out capability, more importantly, without use of complicated microvalves and microtubing systems for liquid transfer. Copyright © 2015 Elsevier B.V. All rights reserved.

Early regimes of water capillary flow in slit silica nanochannels.

PubMed

Oyarzua, Elton; Walther, Jens H; Mejía, Andrés; Zambrano, Harvey A

2015-06-14

Molecular dynamics simulations are conducted to investigate the initial stages of spontaneous imbibition of water in slit silica nanochannels surrounded by air. An analysis is performed for the effects of nanoscopic confinement, initial conditions of liquid uptake and air pressurization on the dynamics of capillary filling. 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 a constant velocity and a plug flow profile. In this regime, the meniscus formation process plays a central role in the imbibition rate. Thereafter, a transitional regime takes place, in which, the force balance has significant contributions from both inertia and viscous friction. Subsequently, a regime wherein viscous forces dominate the capillary force balance is attained. Flow velocity profiles identify the passage from an inviscid flow to a developing Poiseuille flow. Gas density profiles ahead of the capillary front indicate a transient accumulation of air on the advancing meniscus. Furthermore, slower capillary filling rates computed for higher air pressures reveal a significant retarding effect of the gas displaced by the advancing meniscus.

MSblender: A probabilistic approach for integrating peptide identifications from multiple database search engines.

PubMed

Kwon, Taejoon; Choi, Hyungwon; Vogel, Christine; Nesvizhskii, Alexey I; Marcotte, Edward M

2011-07-01

Shotgun proteomics using mass spectrometry is a powerful method for protein identification but suffers limited sensitivity in complex samples. Integrating peptide identifications from multiple database search engines is a promising strategy to increase the number of peptide identifications and reduce the volume of unassigned tandem mass spectra. Existing methods pool statistical significance scores such as p-values or posterior probabilities of peptide-spectrum matches (PSMs) from multiple search engines after high scoring peptides have been assigned to spectra, but these methods lack reliable control of identification error rates as data are integrated from different search engines. We developed a statistically coherent method for integrative analysis, termed MSblender. MSblender converts raw search scores from search engines into a probability score for every possible PSM and properly accounts for the correlation between search scores. The method reliably estimates false discovery rates and identifies more PSMs than any single search engine at the same false discovery rate. Increased identifications increment spectral counts for most proteins and allow quantification of proteins that would not have been quantified by individual search engines. We also demonstrate that enhanced quantification contributes to improve sensitivity in differential expression analyses.

MSblender: a probabilistic approach for integrating peptide identifications from multiple database search engines

PubMed Central

Kwon, Taejoon; Choi, Hyungwon; Vogel, Christine; Nesvizhskii, Alexey I.; Marcotte, Edward M.

2011-01-01

Shotgun proteomics using mass spectrometry is a powerful method for protein identification but suffers limited sensitivity in complex samples. Integrating peptide identifications from multiple database search engines is a promising strategy to increase the number of peptide identifications and reduce the volume of unassigned tandem mass spectra. Existing methods pool statistical significance scores such as p-values or posterior probabilities of peptide-spectrum matches (PSMs) from multiple search engines after high scoring peptides have been assigned to spectra, but these methods lack reliable control of identification error rates as data are integrated from different search engines. We developed a statistically coherent method for integrative analysis, termed MSblender. MSblender converts raw search scores from search engines into a probability score for all possible PSMs and properly accounts for the correlation between search scores. The method reliably estimates false discovery rates and identifies more PSMs than any single search engine at the same false discovery rate. Increased identifications increment spectral counts for all detected proteins and allow quantification of proteins that would not have been quantified by individual search engines. We also demonstrate that enhanced quantification contributes to improve sensitivity in differential expression analyses. PMID:21488652

Thermodynamics of Capillary Rise: Why Is the Meniscus Curved?

ERIC Educational Resources Information Center

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.

Nonuniformity of the chemical composition of a capillary discharge plasma

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

Kocharyan, A. E.; Bobrova, N. A.; Sasorov, P. V.

A steady-state distribution of the concentration of two ion species in a capillary discharge plasma is studied using MHD equations for a plasma with a spatially nonuniform, time-dependent chemical composition. In our case, the set of equations is significantly simplified because of the steady-state character and symmetry of the problem. Even with such simplification, however, some results could be obtained only by numerical integration. The factors affecting the distribution of heavy ions are studied. It is shown that the distribution of the heavy impurity over the discharge cross section can be much more nonuniform than the distribution of the mainmore » component (hydrogen). A simple criterion for such a nonuniformity is obtained.« less

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

NASA Astrophysics Data System (ADS)

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.

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

PubMed

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.

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

NASA Astrophysics Data System (ADS)

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

2012-10-01

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

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

PubMed

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

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

NASA Astrophysics Data System (ADS)

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

2017-08-01

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

Idiopathic Systemic Capillary Leak Syndrome (Clarkson's Disease): The Mayo Clinic Experience

PubMed Central

Kapoor, Prashant; Greipp, Patricia T.; Schaefer, Eric W.; Mandrekar, Sumithra J.; Kamal, Arif H.; Gonzalez-Paz, Natalia C.; Kumar, Shaji; Greipp, Philip R.

2010-01-01

OBJECTIVE: To determine clinical features, natural history, and outcome of a well-defined cohort of 25 consecutive patients with idiopathic systemic capillary leak syndrome (SCLS) evaluated at a tertiary care center. PATIENTS AND METHODS: Records of patients diagnosed as having SCLS from November 1, 1981, through April 30, 2008, were reviewed. Descriptive statistics were used to analyze patient demographics, clinical features, complications, and therapeutic interventions. RESULTS: Of the 34 patients whose records were reviewed, 25 fulfilled all diagnostic criteria for SCLS. The median age at diagnosis of SCLS was 44 years. Median follow-up of surviving patients was 4.9 years, and median time to diagnosis from symptom onset was 1.1 years (interquartile range, 0.5-4.1 years). Flulike illness or myalgia was reported by 14 patients (56%) at onset of an acute attack of SCLS, and rhabdomyolysis developed in 9 patients (36%). Patients with a greater decrease in albumin level had a higher likelihood of developing rhabdomyolysis (p=.03). Monoclonal gammopathy, predominantly of the IgG-κ type, was found in 19 patients (76%). The progression rate to multiple myeloma was 0.7% per person-year of follow-up. The overall response rate to the different therapies was 76%, and 24% of patients sustained durable (>2 years) complete remission. The estimated 5-year overall survival rate was 76% (95% confidence interval, 59%-97%). CONCLUSION: Systemic capillary leak syndrome, a rare disease that occurs in those of middle age, is usually diagnosed after a considerable delay from onset of symptoms. The degree of albumin decrement during an attack correlates with development of rhabdomyolysis. A reduction in the frequency and/or the severity of attacks was seen in nearly three-fourths of patients who were offered empirical therapies. The rate of progression to multiple myeloma appears to be comparable to that of monoclonal gammopathy of undetermined significance. PMID:20634497

Capillary fluctuations of surface steps: An atomistic simulation study for the model Cu(111) system

NASA Astrophysics Data System (ADS)

Freitas, Rodrigo; Frolov, Timofey; Asta, Mark

2017-10-01

Molecular dynamics (MD) simulations are employed to investigate the capillary fluctuations of steps on the surface of a model metal system. The fluctuation spectrum, characterized by the wave number (k ) dependence of the mean squared capillary-wave amplitudes and associated relaxation times, is calculated for 〈110 〉 and 〈112 〉 steps on the {111 } surface of elemental copper near the melting temperature of the classical potential model considered. Step stiffnesses are derived from the MD results, yielding values from the largest system sizes of (37 ±1 ) meV/A ˚ for the different line orientations, implying that the stiffness is isotropic within the statistical precision of the calculations. The fluctuation lifetimes are found to vary by approximately four orders of magnitude over the range of wave numbers investigated, displaying a k dependence consistent with kinetics governed by step-edge mediated diffusion. The values for step stiffness derived from these simulations are compared to step free energies for the same system and temperature obtained in a recent MD-based thermodynamic-integration (TI) study [Freitas, Frolov, and Asta, Phys. Rev. B 95, 155444 (2017), 10.1103/PhysRevB.95.155444]. Results from the capillary-fluctuation analysis and TI calculations yield statistically significant differences that are discussed within the framework of statistical-mechanical theories for configurational contributions to step free energies.

A Simple Double-Source Model for Interference of Capillaries

ERIC Educational Resources Information Center

Hou, Zhibo; Zhao, Xiaohong; Xiao, Jinghua

2012-01-01

A simple but physically intuitive double-source model is proposed to explain the interferogram of a laser-capillary system, where two effective virtual sources are used to describe the rays reflected by and transmitted through the capillary. The locations of the two virtual sources are functions of the observing positions on the target screen. An…

A capillary-driven micromixer: idea and fabrication

NASA Astrophysics Data System (ADS)

Lee, Chun-Te; Lee, Chun-Che

2012-10-01

Microfluidic systems have been drawing attention upon the various branches of engineering science and the allied areas within biology and biomedicine. In this paper, a fabrication of a capillary-driven micromixer using photoresist JSR and glasses is proposed. We design three types of planar capillary-driven micormixers with different sizes of baffles in the channel. Flow tests have shown that the micromixer with a baffle gap of 100 μm and space of 100 μm reaches a best mixing performance of 93% in gray-level image analysis.

Investigation of Capillary Limit in a Loop Heat Pipe

NASA Technical Reports Server (NTRS)

Ku, Jentung; Ottenstein, Laura; Rogers, Paul; Cheung, Kwok; Obenschain, Arthur F. (Technical Monitor)

2001-01-01

This paper presets an experimental study on the capillary limit of a loop heat pipe (LHP) at low powers. The slow thermal response of the loop at low powers made it possible to observe interactions among various components after the capillary limit was exceeded. The capillary limit at low powers was achieved by imposing additional pressure drops on the vapor line through the use of a metering valve. A differential pressure transducer was also used to measure the pressure drop across the evaporator and the compensation chamber (CC). Test results show that when the capillary limit is exceeded, vapor will penetrate the primary wick, resulting in a partial dry-out of the evaporator and a rapid increase of the CC temperature. Because the evaporator can tolerate vapor bubbles, the LHP will continue to function and may reach a new steady state at the higher temperature. Thus, the LHP will exhibit a graceful degradation in performance rather than a complete failure. Moreover, the loop can recover from a partial dry-out by reducing the heat load without a re-start.

Crossover from capillary fingering to viscous fingering in a rough fracture

NASA Astrophysics Data System (ADS)

Hu, R.; Chen, Y.; Wu, D. S.

2017-12-01

Controlled by the competition between capillary and viscous forces, the displacement patterns of one fluid displacing another more viscous one exhibit capillary fingering, viscous fingering, and the crossover between the two. Although extensive studies have investigated viscous and capillary fingerings in porous and fractured media, a few studies focused on the crossover in rough fractures, and how viscous and capillary forces affect the crossover remains unclear. Using a transparent fracture visualization system, we studied how the competition impacts the crossover in a horizontal rough fracture. Drainage experiments of water displacing oil were conducted at seven flow rates (capillary number log10Ca ranging from -7.07 to -3.07) and four viscosity ratios (M = 1/1000, 1/500, 1/100 and 1/50). We consistently observed lower invading fluid saturations in the crossover zone. In addition, we proposed a phase diagram for the displacement patterns in a rough fracture that is consistent with similar studies in porous media. Based on real-time imaging and statistical analysis of the invasion morphology, we showed that the competition between the capillary and viscous forces is responsible for the saturation reduction in the crossover zone. In this zone, finger propagation toward the outlet (characteristic of viscous fingering) as well as void-filling in the transverse and backward directions (characteristic of capillary fingering), are both suppressed. Therefore, the invading fluid tends to occupy larger apertures with higher characteristic front velocity, promoting void-filling toward the outlet with thinner finger growth and resulting in a larger volume of defending fluid left behind.

Irradiation of orderly multiline spectra from linear plasma formed by vacuum discharge capillary

NASA Astrophysics Data System (ADS)

Sato, Eiichi; Hayasi, Yasuomi; Germer, Rudolf; Ojima, Hidenori; Takayama, Kazuyoshi; Ido, Hideaki

2005-03-01

The fundamental experiments for measuring soft x-ray characteristics from the vacuum capillary are described. These experiments are primarily performed in order to generate intense soft x rays. The generator consists of a high-voltage power supply, a polarity-inversion ignitron pulse generator, a turbomolecular pump, and a radiation tube with a capillary. A high-voltage condenser of 200 nF in the pulse generator is charged up to 20 kV by the power supply, and the electric charges in the condenser are discharged to the capillary in the tube after closing the ignitron. During the discharge, weakly ionized plasma forms on the inner and outer sides of a capillary. In the present work, the pump evacuates air from the tube with a pressure of about 1 mPa, and a demountable capillary was developed in order to measure x-ray spectra according to changes in the capillary length. In this capillary, the anode (target) and cathode elements can be changed corresponding to the objectives. The capillary diameter is 2.0 mm, and the length is adjusted from 1 to 50 mm. When a capillary with aluminum anode and cathode electrodes was employed, both the cathode voltage and the discharge current almost displayed damped oscillations. The peak values of the voltage and current increased when the charging voltage was increased, and their maximum values were -11.5 kV and 4.7 kA, respectively. The x-ray durations observed by a 1.6 μm aluminum filter were less than 30 μs. In the spectrum measurement, we observed orderly multi-line spectra. The line photon energies seldom varied according to changes in the condenser charging voltage and to changes in the electrode element. The line number decreased with corresponding decreases in the capillary length.

Capillary photoelectrode structures for photoelectrochemical and photocatalytic cells

DOEpatents

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

2017-05-02

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

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

PubMed

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.

Nerve injury affects the capillary supply in rat slow and fast muscles differently.

PubMed

Cebasek, Vita; Radochová, Barbora; Ribaric, Samo; Kubínová, Lucie; Erzen, Ida

2006-02-01

The goal of this study was to determine the acute effects of permanent denervation on the length density of the capillary network in rat slow soleus (SOL) and fast extensor digitorum longus (EDL) muscles and the effect of short-lasting reinnervation in slow muscle only. Denervation was performed by cutting the sciatic nerve. Both muscles were excised 2 weeks later. Reinnervation was studied 4 weeks after nerve crush in SOL muscle only. Capillaries and muscle fibres were visualised by triple immunofluorescent staining with antibodies against CD31 and laminin and with fluorescein-labelled Griffonia (Bandeira) simplicifolia lectin. A recently developed stereological approach allowing the estimation of the length of capillaries adjacent to each individual fibre (Lcap/Lfib) was employed. Three-dimensional virtual test grids were applied to stacks of optical images captured with a confocal microscope and their intersections with capillaries and muscle fibres were counted. Interrelationships among capillaries and muscle fibres were demonstrated with maximum intensity projection of the acquired stacks of optical images. The course of capillaries in EDL seemed to be parallel to the fibre axes, whereas in SOL, their preferential direction deviated from the fibre axes and formed more cross-connections among neighbouring capillaries. Lcap/Lfib was clearly reduced in denervated SOL but remained unchanged in EDL, although the muscle fibres significantly atrophied in both muscle types. When soleus muscle was reinnervated, capillary length per unit fibre length was completely restored. The physiological background for the different responses of the capillary network in slow and fast muscle is discussed.

Low internal pressure in femtoliter water capillary bridges reduces evaporation rates

PubMed Central

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

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

PubMed

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.

A sex-specific relationship between capillary density and anaerobic threshold.

PubMed

Robbins, Jennifer L; Duscha, Brian D; Bensimhon, Daniel R; Wasserman, Karlman; Hansen, James E; Houmard, Joseph A; Annex, Brian H; Kraus, William E

2009-04-01

Although both capillary density and peak oxygen consumption (Vo(2)) improve with exercise training, it is difficult to find a relationship between these two measures. It has been suggested that peak Vo(2) may be more related to central hemodynamics than to the oxidative potential of skeletal muscle, which may account for this observation. We hypothesized that change in a measure of submaximal performance, anaerobic threshold, might be related to change in skeletal muscle capillary density, a marker of oxidative potential in muscle, with training. Due to baseline differences among these variables, we also hypothesized that relationships might be sex specific. A group of 21 subjects completed an inactive control period, whereas 28 subjects (17 men and 11 women) participated in a 6-mo high-intensity exercise program. All subjects were sedentary, overweight, and dyslipidemic. Potential relationships were assessed between change in capillary density with both change in Vo(2) at peak and at anaerobic threshold with exercise training. All variables and relationships were assessed for sex-specific effects. Change in peak Vo(2) was not related to change in capillary density after exercise training in either sex. Men had a positive correlation between change in Vo(2) at anaerobic threshold and change in capillary density with exercise training (r = 0.635; P < 0.01), whereas women had an inverse relationship (r = -0.636; P < 0.05) between the change in these variables. These findings suggest that, although enhanced capillary density is associated with training-induced improvements in submaximal performance in men, this relationship is different in women.

Modulation of C. elegans Touch Sensitivity Is Integrated at Multiple Levels

PubMed Central

Chen, Xiaoyin

2014-01-01

Sensory systems can adapt to different environmental signals. Here we identify four conditions that modulate anterior touch sensitivity in Caenorhabditis elegans after several hours and demonstrate that such sensory modulation is integrated at multiple levels to produce a single output. Prolonged vibration involving integrin signaling directly sensitizes the touch receptor neurons (TRNs). In contrast, hypoxia, the dauer state, and high salt reduce touch sensitivity by preventing the release of long-range neuroregulators, including two insulin-like proteins. Integration of these latter inputs occurs at upstream neurohormonal cells and at the insulin signaling cascade within the TRNs. These signals and those from integrin signaling converge to modulate touch sensitivity by regulating AKT kinases and DAF-16/FOXO. Thus, activation of either the integrin or insulin pathways can compensate for defects in the other pathway. This modulatory system integrates conflicting signals from different modalities, and adapts touch sensitivity to both mechanical and non-mechanical conditions. PMID:24806678

Gas-filled capillaries for plasma-based accelerators

NASA Astrophysics Data System (ADS)

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.

Development of a Specific Impulse Balance for a Pulsed Capillary Discharge (Preprint)

DTIC Science & Technology

2008-06-13

thrust stand [rad/s] I. Introduction A capillary discharge based coaxial , electrothermal pulsed plasma thruster (PPT) is currently under...20-23 July 2008. 14. ABSTRACT A capillary discharge based pulsed plasma thruster is currently under development at the Air Force Research...Edwards AFB, CA 93524 A capillary discharge based pulsed plasma thruster is currently under development at the Air Force Research Laboratory. A

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

NASA Astrophysics Data System (ADS)

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.

Student Design Challenges in Capillary Flow

NASA Technical Reports Server (NTRS)

Stocker, Dennis P.; Wollman, Andrew; Hall, Nancy R.; Weislogel, Mark; DeLombard, Richard

2016-01-01

For some grade 8-12 students, capillary flow has bridged the gap between the classroom and research facility, from normal gravity to microgravity. In the past four years, NASA and the Portland State University (PSU) have jointly challenged students to design test cells, using Computer-Aided Design (CAD), to study capillary action in microgravity as PSU has done on the International Space Station (ISS). Using the student-submitted CAD drawings, the test cells were manufactured by PSU and tested in their 2.1-second drop tower. The microgravity results were made available online for student analysis and reporting. Over 100 such experiments have been conducted, where there has been participation from 15 states plus a German school for the children of U.S. military personnel. In 2016, a related NASA challenge was held in partnership with the ASGSR, again, based on the research conducted by PSU. In this challenge, grade 9-12 students designed and built devices using capillary action to launch droplets as far as possible in NASAs 2.2 Second Drop Tower. Example results will be presented by students at this conference. The challenges engage students in ISS science and technology and can inspire them to pursue technical careers.

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

NASA Astrophysics Data System (ADS)

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

2013-11-01

We apply the capillary beam-focusing method for the C60 fullerene projectiles in the velocity range between 0.14 and 0.2 a.u. We study the C60 transmission properties through two different types of capillaries: (1) borosilicate glass microcapillary with an outlet diameter of 5.5 μm, and (2) Al2O3 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 C60 beams that are focused in the area equal to the capillary outlet diameter. Minor components are charge-exchanged C60 ions and charged or neutral fragments (fullerene-like C60-2m and small Cn particles), and their fractions decrease with decreasing the projectile velocity. It is concluded that the C60 transmission fraction is considerably high for both types of the capillaries in the present velocity range.

Cerebral small vessel disease: Capillary pathways to stroke and cognitive decline

PubMed Central

Engedal, Thorbjørn S; Moreton, Fiona; Hansen, Mikkel B; Wardlaw, Joanna M; Dalkara, Turgay; Markus, Hugh S; Muir, Keith W

2015-01-01

Cerebral small vessel disease (SVD) gives rise to one in five strokes worldwide and constitutes a major source of cognitive decline in the elderly. SVD is known to occur in relation to hypertension, diabetes, smoking, radiation therapy and in a range of inherited and genetic disorders, autoimmune disorders, connective tissue disorders, and infections. Until recently, changes in capillary patency and blood viscosity have received little attention in the aetiopathogenesis of SVD and the high risk of subsequent stroke and cognitive decline. Capillary flow patterns were, however, recently shown to limit the extraction efficacy of oxygen in tissue and capillary dysfunction therefore proposed as a source of stroke-like symptoms and neurodegeneration, even in the absence of physical flow-limiting vascular pathology. In this review, we examine whether capillary flow disturbances may be a shared feature of conditions that represent risk factors for SVD. We then discuss aspects of capillary dysfunction that could be prevented or alleviated and therefore might be of general benefit to patients at risk of SVD, stroke or cognitive decline. PMID:26661176

Capillary Limit in a Loop Heat Pipe with Dual Evaporators

NASA Technical Reports Server (NTRS)

Ku, Jentung; Birur, Gajanana; Obenschain, Arthur F. (Technical Monitor)

2002-01-01

This paper describes a study on the capillary limit of a loop heat pipe (LHP) with two evaporators and two condensers. Both theoretical analysis and experimental investigation are conducted. Tests include heat load to one evaporator only, even heat loads to both evaporators and uneven heat load to both evaporators. Results show that after the capillary limit is exceeded, vapor will penetrate through the wick of the weaker evaporator and the compensation chamber (CC) of that evaporator will control the loop operating temperature regardless of which CC has been in control prior to the event Because the evaporator can tolerate vapor bubbles, the loop may continue to work and reach a new steady state at a higher operating temperature. The loop may even function with a modest increase in the heat load past the capillary limit With a heat load to only one evaporator, the capillary limit can be identified by rapid increases in the operating temperature and in the temperature difference between the evaporator and the CC. However, it is more difficult to tell when the capillary limit is exceeded if heat loads are applied to both evaporators. In all cases, the loop can recover by reducing the heat load to the loop.

Insight into the stability of poly(diallydimethylammoniumchloride) and polybrene poly cationic coatings in capillary electrophoresis.

PubMed

Pei, Lei; Lucy, Charles A

2014-10-24

Polycationic polymers are widely used in capillary electrophoresis (CE) as surface coatings to prevent protein adsorption and control electroosmotic flow (EOF). Such semi-permanent coatings are formed by flushing the capillary with a quaternary amine-based polymer such as poly(diallydimethylammonium chloride) (PDADMAC) or polybrene. Compared to covalent capillary coatings, the claimed advantages of adsorptive polycation coatings are their simple preparation and that they are not limited to the pH 2-8 range as are covalent coatings. However, while the latter is commonly claimed, few studies have demonstrated the stability of polycationic coatings at extreme pH. Herein PDADMAC and polybrene are studied as model cationic coatings. PDADMAC with higher molecular weight (M.W.) demonstrated higher EOF stability at pH 9.5, with PDADMAC of M.W. less than 200,000 being unstable at pH 9.5. X-ray photoelectron spectroscopy (XPS) shows that the quaternary amines of PDADMAC and polybrene were slowly converted to tertiary amines in alkaline solution and more rapidly when adsorbed on a silica surface. The degraded polycation deprotonated at pH >7, resulting in loss of polymer from the surface and diminishing EOF. Successive multiple ionic layer (SMIL) coatings show greater alkaline stability by distancing the polycation from the surface. Separations of inorganic anions at pH 9.5 illustrate the degradation behavior and enhanced stability of higher M.W. polycationic coatings. Copyright © 2014 Elsevier B.V. All rights reserved.

Influence of tissue metabolism and capillary oxygen supply on arteriolar oxygen transport: a computational model.

PubMed

Moschandreou, T E; Ellis, C G; Goldman, D

2011-07-01

We present a theoretical model for steady-state radial and longitudinal oxygen transport in arterioles containing flowing blood (plasma and red blood cells) and surrounded by living tissue. This model combines a detailed description of convective and diffusive oxygen transport inside the arteriole with a novel boundary condition at the arteriolar lumen surface, and the results provide new mass transfer coefficients for computing arteriolar O(2) losses based on far-field tissue O(2) tension and in the presence of spatially distributed capillaries. A numerical procedure is introduced for calculating O(2) diffusion from an arteriole to a continuous capillary-tissue matrix immediately adjacent to the arteriole. The tissue O(2) consumption rate is assumed to be constant and capillaries act as either O(2) sources or sinks depending on the local O(2) environment. Using the model, O(2) saturation (SO(2)) and tension (PO(2)) are determined for the intraluminal region of the arteriole, as well as for the extraluminal region in the neighbouring tissue. Our model gives results that are consistent with available experimental data and previous intraluminal transport models, including appreciable radial decreases in intraluminal PO(2) for all vessel diameters considered (12-100 μm) and slower longitudinal decreases in PO(2) for larger vessels than for smaller ones, and predicts substantially less diffusion of O(2) from arteriolar blood than do models with PO(2) specified at the edge of the lumen. The dependence of the new mass transfer coefficients on vessel diameter, SO(2) and far-field PO(2) is calculated allowing their application to a wide range of physiological situations. This novel arteriolar O(2) transport model will be a vital component of future integrated models of microvascular regulation of O(2) supply to capillary beds and the tissue regions they support. Copyright © 2011 Elsevier Inc. All rights reserved.

Post-capillary reaction detection in capillary electrophoresis based on the streptavidin-biotin interaction. Optimization and application to single cell analysis.

PubMed

Feltus, A; Hentz, N G; Daunert, S

2001-05-25

A class-selective post-capillary reaction detection method for capillary electrophoresis is described in which a streptavidin-fluorescein isothiocyanate (streptavidin-FITC) conjugate is used to detect biotin moieties. The selective binding of biotin moieties to the streptavidin-FITC conjugate causes an enhancement of fluorescence proportional to the concentration of biotin present. After capillary electrophoresis the separated analytes react with streptavidin-FITC in a coaxial reactor and are then detected either by a benchtop spectrofluorometer (2.5 microM detection limit) or by an epi-fluorescence microscope (1 x 10(-7) M detection limit). The method is used to examine biotinylated species in a crude mammalian cell lysate which was found to contain 83+/-3 fmol in 3600 cell volumes. In addition, it is used to examine the uptake of biotin by individual sea urchin oocytes. The results indicate that, in the oocytes, biocytin is the prevalent form of biotin and its concentration varies widely between cells (mean=2+/-2 microM).

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

PubMed Central

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

2007-01-01

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

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

PubMed

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 < .001). Using the capillary-free 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

Integrated argument-based inquiry with multiple representation approach to promote scientific argumentation skill

NASA Astrophysics Data System (ADS)

Suminar, Iin; Muslim, Liliawati, Winny

2017-05-01

The purpose of this research was to identify student's written argument embedded in scientific inqury investigation and argumentation skill using integrated argument-based inquiry with multiple representation approach. This research was using quasi experimental method with the nonequivalent pretest-posttest control group design. Sample ot this research was 10th grade students at one of High School in Bandung using two classes, they were 26 students of experiment class and 26 students of control class. Experiment class using integrated argument-based inquiry with multiple representation approach, while control class using argument-based inquiry. This study was using argumentation worksheet and argumentation test. Argumentation worksheet encouraged students to formulate research questions, design experiment, observe experiment and explain the data as evidence, construct claim, warrant, embedded multiple modus representation and reflection. Argumentation testinclude problem which asks students to explain evidence, warrants, and backings support of each claim. The result of this research show experiment class students's argumentation skill performed better than control class students that of experiment class was 0.47 and control class was 0.31. The results of unequal variance t-test for independent means show that students'sargumentationskill of experiment class performed better significantly than students'sargumentationskill of control class.

Enhanced laser radiation pressure acceleration of protons with a gold cone-capillary

NASA Astrophysics Data System (ADS)

Lv, Chong; Xie, Bai-Song; Wan, Feng; Hou, Ya-Juan; Jia, Mo-Ran; Sang, Hai-Bo; Hong, Xue-Ren; Liu, Shi-Bing

2017-03-01

A scheme with a gold cone-capillary is proposed to improve the protons acceleration, and involved problems are investigated by using the two-dimensional particle-in-cell simulations. It is demonstrated that the cone-capillary can efficiently guide and collimate the protons to a longer distance and result in a better beam quality with a dense density ≥ 10 n c , monoenergetic peak energy E k ˜ 1.51 GeV , spatial emittance ˜ 0.0088 mm mrad with divergence angle θ ˜ 1.0 ° and diameter ˜ 0.5 μ m . The enhancement is mainly attributed to the focusing effect by the transverse electric field generated by the cone as well as the capillary, which can prevent greatly the protons from expanding in the transverse direction. Comparable to without the capillary, the protons energy spectra have a stable monoenergetic peak and divergence angle nearby 1.0 ° in longer time. Besides, the efficiency of acceleration depending on the capillary length is explored, and the optimal capillary length is also achieved. Such a target may be beneficial to many applications such as ion fast ignition in inertial fusion, proton therapy and so on.

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

PubMed

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.

Interfacial tension measurement of immiscible liq uids using a capillary tube

NASA Technical Reports Server (NTRS)

Rashidnia, N.; Balasubramaniam, R.; Delsignore, D.

1992-01-01

The interfacial tension of immiscible liquids is an important thermophysical property that is useful in the behavior of liquids both in microgravity (Martinez et al. (1987) and Karri and Mathur (1988)) and in enhanced oil recovery processes under normal gravity (Slattery (1974)). Many techniques are available for its measurement, such as the ring method, drop weight method, spinning drop method, and capillary height method (Adamson (1960) and Miller and Neogi (1985)). Karri and Mathur mention that many of the techniques use equations that contain a density difference term and are inappropriate for equal density liquids. They reported a new method that is suitable for both equal and unequal density liquids. In their method, a capillary tube forms one of the legs of a U-tube. The interfacial tension is related to the heights of the liquids in the cups of the U-tube above the interface in the capillary. Our interest in this area arose from a need to measure small interfacial tension (around 1 mN/m) for a vegetable oil/silicon oil system that was used in a thermocapillary drop migration experiment (Rashidnia and Balasubramaniam (1991)). In our attempts to duplicate the method proposed by Karri and Mathur, we found it quite difficult to anchor the interface inside the capillary tube; small differences of the liquid heights in the cups drove the interface out of the capillary. We present an alternative method using a capillary tube to measure the interfacial tensions of liquids of equal or unequal density. The method is based on the combined capillary rises of both liquids in the tube.

Storing self-contained gel capillary cassettes for POC medical diagnostics.

PubMed

Manage, Dammika P; Lauzon, Jana; Zahariadis, George; Pilarski, Linda M

2013-10-21

For effective clinical uptake of the lab on a chip/point of care technology (LOC-POC), in addition to cost advantages LOC-POC devices should offer multiple patient screening panels for related diseases as well as cold-chain transportation and storage abilities. We recently described a device that performs polymerase chain reaction (PCR) to simultaneously screen raw clinical samples from up to 16 patients for multiple infectious agents (Manage et al., Lab Chip, 2013, 13, 2576-2584). This cassette contains glass capillaries with desiccated semi-solid acrylamide gels that include all the reagents except for the sample, with integrated quality control. Here we report the development of protocols to store assembled PCR cassettes at room temperature, 4 °C or -20 °C as well as at +40 °C. We show that our cassettes are stable, with no loss of activity for at least 3 months at RT and at least 7 months at 4 °C and -20 °C. However, the activity of desiccated cassettes degrades when stored for more than 2 weeks at 40 °C, insufficient time for post-manufacture delivery and use of cassette PCR. To address this, we have evaluated two stage storage protocols. PCR cassettes can initially be stored at 4 °C and -20 °C for prolonged periods of time and removed for shorter term storage at RT, retaining activity for at least a month, which would facilitate transport to remote areas for testing. Effective use of cassette PCR in high temperature regions of the world, for experimental purposes defined here as 40 °C, appears to be feasible only after a first stage storage in the cold, followed by no more than 1 week at 40 °C. This should allow sufficient time for delivery by the manufacturer to a central area well served by power and refrigeration, for later ambient temperature transport and use in under-resourced areas that lack refrigeration.

The application of capillary microsampling in GLP toxicology studies.

PubMed

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.

Handling missing rows in multi-omics data integration: multiple imputation in multiple factor analysis framework.

PubMed

Voillet, Valentin; Besse, Philippe; Liaubet, Laurence; San Cristobal, Magali; González, Ignacio

2016-10-03

In omics data integration studies, it is common, for a variety of reasons, for some individuals to not be present in all data tables. Missing row values are challenging to deal with because most statistical methods cannot be directly applied to incomplete datasets. To overcome this issue, we propose a multiple imputation (MI) approach in a multivariate framework. In this study, we focus on multiple factor analysis (MFA) as a tool to compare and integrate multiple layers of information. MI involves filling the missing rows with plausible values, resulting in M completed datasets. MFA is then applied to each completed dataset to produce M different configurations (the matrices of coordinates of individuals). Finally, the M configurations are combined to yield a single consensus solution. We assessed the performance of our method, named MI-MFA, on two real omics datasets. Incomplete artificial datasets with different patterns of missingness were created from these data. The MI-MFA results were compared with two other approaches i.e., regularized iterative MFA (RI-MFA) and mean variable imputation (MVI-MFA). For each configuration resulting from these three strategies, the suitability of the solution was determined against the true MFA configuration obtained from the original data and a comprehensive graphical comparison showing how the MI-, RI- or MVI-MFA configurations diverge from the true configuration was produced. Two approaches i.e., confidence ellipses and convex hulls, to visualize and assess the uncertainty due to missing values were also described. We showed how the areas of ellipses and convex hulls increased with the number of missing individuals. A free and easy-to-use code was proposed to implement the MI-MFA method in the R statistical environment. We believe that MI-MFA provides a useful and attractive method for estimating the coordinates of individuals on the first MFA components despite missing rows. MI-MFA configurations were close to the true

Development and demonstration of a water-window soft x-ray microscope using a Z-pinching capillary discharge source

NASA Astrophysics Data System (ADS)

Nawaz, M. F.; Jancarek, Alexandr; Nevrkla, Michal; Duda, Martin Jakub; Pina, Ladislav

2017-05-01

The development and demonstration of a soft X-ray (SXR) microscope, based on a Z-pinching capillary discharge source has been realized. The Z-pinching plasma acts as a source of SXR radiation. A ceramic capacitor bank is pulsed charged up to 80 kV, and discharged through a pre- ionized nitrogen filled ceramic capillary. The discharge current has an amplitude of 25 kA. Working within the water-window spectral region (λ = 2.88 nm), corresponding to the 1s2-1s2p quantum transition of helium-like nitrogen (N5+), the microscope has a potential in exploiting the natural contrast existing between the K-absorption edges of carbon and oxygen as the main constituents of biological materials, and hence imaging them with high spatial resolution. The SXR microscope uses the grazing incidence ellipsoidal condenser mirror for the illumination, and the Fresnel zone plate optics for the imaging of samples onto a BI-CCD camera. The half- pitch spatial resolution of 100 nm [1] was achieved, as demonstrated by the knife-edge test. In order to enhance the photon-flux at the sample plane, a new scheme for focusing the radiation, from multiple capillary sources has been investigated. Details about the source, and the construction of the microscope are presented and discussed.

Hybrid Phospholipid Bilayer Coatings for Separations of Cationic Proteins in Capillary Zone Electrophoresis

PubMed Central

Gallagher, Elyssia S.; Adem, Seid M.; Bright, Leonard K.; Calderon, Isen A. C.; Mansfield, Elisabeth; Aspinwall, Craig A.

2014-01-01

Protein separations in capillary zone electrophoresis (CZE) suffer from non-specific adsorption of analytes to the capillary surface. Semi-permanent phospholipid bilayers (PLBs) have been used to minimize adsorption, but must be regenerated regularly to ensure reproducibility. We investigated the formation, characterization, and use of hybrid phospholipid bilayers (HPBs) as more stable biosurfactant capillary coatings for CZE protein separations. HPBs are formed by covalently modifying a support with a hydrophobic monolayer onto which a self-assembled lipid monolayer is deposited. Monolayers prepared in capillaries using 3-cyanopropyldimethylchlorosilane (CPDCS) or n-octyldimethylchlorosilane (ODCS) yielded hydrophobic surfaces with lowered surface free energies of 6.0 ± 0.3 or 0.2 ± 0.1 mJ m−2, respectively, compared to 17 ± 1 mJ m−2 for bare silica capillaries. HPBs were formed by subsequently fusing vesicles comprised of 1,2-dilauroyl-sn-glycero-3-phosphocholine or 1,2-dioleoyl-sn-glycero-3-phosphocholine to CPDCS- or ODCS-modified capillaries. The resultant HPB coatings shielded the capillary surface and yielded reduced electroosmotic mobility (1.3 – 1.9 × 10−4 cm2 V−1s−1) compared to CPDCS- and ODCS-modified or bare capillaries (3.6 ± 0.2 × 10−4 cm2 V−1s−1, 4.8 ± 0.4 × 10−4 cm2 V−1s−1, and 6.0 ± 0.2 × 10−4 cm2 V−1s−1, respectively), with increased stability compared to PLB coatings. HPB-coated capillaries yielded reproducible protein migration times (RSD ≤ 3.6 %, n ≥ 6) with separation efficiencies as high as 200,000 plates m−1. PMID:24459085

Portable, Battery Operated Capillary Electrophoresis with Optical Isomer Resolution Integrated with Ionization Source for Mass Spectrometry

NASA Astrophysics Data System (ADS)

Moini, Mehdi; Rollman, Christopher M.

2016-03-01

We introduce a battery operated capillary electrophoresis electrospray ionization (CE/ESI) source for mass spectrometry with optical isomer separation capability. The source fits in front of low or high resolution mass spectrometers similar to a nanospray source with about the same weight and size. The source has two high voltage power supplies (±25 kV HVPS) capable of operating in forward or reverse polarity modes and powered by a 12 V rechargeable lithium ion battery with operation time of ~10 h. In ultrafast CE mode, in which short narrow capillaries (≤15 μm i.d., 15-25 cm long) and field gradients ≥1000 V/cm are used, peak widths at the base are <1 s wide. Under these conditions, the source provides high resolution separation, including optical isomer resolution in ~1 min. Using a low resolution mass spectrometer (LTQ Velos) with a scan time of 0.07 s/scan, baseline separation of amino acids and their optical isomers were achieved in ~1 min. Moreover, bovine serum albumin (BSA) was analyzed in ~1 min with 56% coverage using the data-dependent MS/MS. Using a high resolution mass spectrometer (Thermo Orbitrap Elite) with 15,000 resolution, the fastest scan time achieved was 0.15 s, which was adequate for CE-MS analysis when optical isomer separation is not required or when the optical isomers were well separated. Figures of merit including a detection limit of 2 fmol and linear dynamic range of two orders of magnitude were achieved for amino acids.

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

PubMed

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.

Capillary ion electrophoresis of inorganic anions and uric acid in human saliva using a polyvinyl alcohol coated capillary column and hexamethonium chloride as additive of background electrolyte.

PubMed

Mori, Masanobu; Yamamoto, Tsukasa; Kaseda, Maki; Yamada, Sachiko; Itabashi, Hideyuki

2012-03-01

A combination of polyvinyl alcohol chemically coated capillary (PVA capillary) and background electrolyte (BGE) with ion-pair reagent (hexamethonium dichloride, HMC) was used on capillary ion electrophoresis-UV detection (CIE-UV) for analysis of Br⁻, I⁻, NO₂⁻, NO₃⁻, SCN⁻ and uric acid in human saliva. The PVA capillary prepared in our laboratory minimized electro-osmotic flow (EOF) at the BGE in pH 3-10, and did not affect the UV detection at 210 nm by the PVA-layer on capillary wall. Therefore, use of the PVA capillary was suitable for sensitive UV detection for analyte anions, as well as suppression of protein adsorption. In this study, we optimized the BGE of 10 mM phosphate plus 10 mM HMC with applying a voltage of -15 kV. HMC as an additive to BGE could manipulate the electrophoretic mobility of anions, without electrostatic adsorption to the PVA capillary. The CIE-UV could separate and determine analyte anions in human saliva containing proteins by the direct injection without pretreatments such as dilution or deproteinization within 13 min. The relative standard deviations (n=10) were ranged of 0.5-1.6% in migration times, 2.2-6.8% in peak heights and 2.8-8.4% in peak areas. The limits of detection (S/N=3) were ranged of 3.42-6.87 μM. The peak height of anions in this system was gradually decreased through the successive injections of saliva samples, but the problem was successfully solved by periodically conditioning the PVA capillary. The quantifiability of anions in human saliva samples by the CIE-UV was evaluated through the recoveries by standard addition methods and comparison of other representative analytical methods, as well as identification by ion chromatography (IC). From the anion analyses in 12 different saliva samples, the CIE-UV demonstrated that can obtain obvious differences in concentrations of SCN⁻ between of smoker and non-smoker and those of uric acid between male and female with satisfactory results. Copyright �

Investigation of pressure drop in capillary tube for mixed refrigerant Joule-Thomson cryocooler

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

Ardhapurkar, P. M.; Sridharan, Arunkumar; Atrey, M. D.

2014-01-29

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 onmore » 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.« less

Effects of Riot Control Training on Systemic Microvascular Reactivity and Capillary Density.

PubMed

Pereira, Flavio; de Moraes, Roger; Van Bavel, Diogo; De Lorenzo, Andrea; Tibirica, Eduardo

2018-03-14

The main aim of the present study is to evaluate the effects of strenuous exercise, related to special military training for riot control, on systemic microvascular endothelial function and skin capillary density. Endothelium-dependent microvascular reactivity was evaluated in the forearm skin of healthy military trainees (age 23.4 ± 2.3 yr; n = 15) using laser speckle contrast imaging coupled with cutaneous acetylcholine (ACh) iontophoresis and post-occlusive reactive hyperemia (PORH). Functional capillary density was assessed using high-resolution, intra-vital color microscopy in the dorsum of the middle phalanx. Capillary recruitment (capillary reserve) was evaluated using PORH. Microcirculatory tests were performed before and after a 5-wk special military training for riot control. Microvascular endothelium-dependent vasodilatory responses were markedly and significantly reduced after training, compared with values obtained before training. The peak values of microvascular conductance obtained during iontophoresis of ACh or PORH before training (0.84 ± 0.22 and 0.94 ± 0.72 APU/mmHg, respectively) were markedly reduced after training (0.47 ± 0.11 and 0.71 ± 0.14 APU/mmHg; p < 0.0001 and p = 0.0037, respectively). Endothelium-dependent capillary recruitment was significantly reduced after training (before 101 ± 9 and after 95 ± 8 capillaries/mm2; p = 0.0007). The present study showed that a 5-wk strenuous military training, performed in unfavorable climatic conditions, induces marked systemic microvascular dysfunction, mainly characterized by reduced endothelium-dependent microvascular vasodilation and blunted capillary recruitment.

Protein contact prediction by integrating deep multiple sequence alignments, coevolution and machine learning.

PubMed

Adhikari, Badri; Hou, Jie; Cheng, Jianlin

2018-03-01

In this study, we report the evaluation of the residue-residue contacts predicted by our three different methods in the CASP12 experiment, focusing on studying the impact of multiple sequence alignment, residue coevolution, and machine learning on contact prediction. The first method (MULTICOM-NOVEL) uses only traditional features (sequence profile, secondary structure, and solvent accessibility) with deep learning to predict contacts and serves as a baseline. The second method (MULTICOM-CONSTRUCT) uses our new alignment algorithm to generate deep multiple sequence alignment to derive coevolution-based features, which are integrated by a neural network method to predict contacts. The third method (MULTICOM-CLUSTER) is a consensus combination of the predictions of the first two methods. We evaluated our methods on 94 CASP12 domains. On a subset of 38 free-modeling domains, our methods achieved an average precision of up to 41.7% for top L/5 long-range contact predictions. The comparison of the three methods shows that the quality and effective depth of multiple sequence alignments, coevolution-based features, and machine learning integration of coevolution-based features and traditional features drive the quality of predicted protein contacts. On the full CASP12 dataset, the coevolution-based features alone can improve the average precision from 28.4% to 41.6%, and the machine learning integration of all the features further raises the precision to 56.3%, when top L/5 predicted long-range contacts are evaluated. And the correlation between the precision of contact prediction and the logarithm of the number of effective sequences in alignments is 0.66. © 2017 Wiley Periodicals, Inc.

Critical capillary channel flow

NASA Astrophysics Data System (ADS)

Grah, Aleksander; Klatte, Jörg; Dreyer, Michael E.

The main subject are numerical studies on capillary channel flow, based on results of the sounding rocket experiments TEXUS 41/42. The flow through a capillary channel is established by a gear pump at the outlet. The channel, consists of two parallel glass plates with a width of 25 mm, a gap of 10 mm and a length of 12 mm. The meniscus of a compensation tube maintains a constant system pressure. Steady and dynamic pressure effects in the system force the surfaces to bend inwards. A maximum flow rate is achieved when the free surface collapses and gas ingestion occurs at the outlet. This critical flow rate depends on the channel geometry, the flow regime and the liquid properties. The aim of the experiments is the determination of the free surface shape and to find the maximum flow rate. In order to study the unsteady liquid loop behaviour, a dimensionless transient model was developed. It is based on the unsteady Bernoulli equation, the unsteady continuity equation and geometrical conditions for the surface curvature and the flow cross-section. The pressure is related to the curvature of the free liquid surface by the dimensionless Gauss-Laplace equation with two principal radii. The experimental and evaluated contour data shows good agreement for a sequence of transient flow rate perturbations. The surface oscillation frequencies and amplitudes can be predicted with quite high accuracy. The dynamic of the pump is defined by the increase of the flow rate in a time period. To study the unsteady system behavior in the "worst case", we use a perturbations related to the natural frequency of the oscillating liquid. In the case of steady flow at maximum flow rate, when the "choking" effect occurs, the surfaces collapse and cause gas ingestion into the channel. This effect is related to the Speed Index. At the critical flow rate the Speed Index reaches the value Sca = 1, in analogy to the Mach Number. Unsteady choking does not necessarily cause surface collapse. We show

A sex-specific relationship between capillary density and anaerobic threshold

PubMed Central

Robbins, Jennifer L.; Duscha, Brian D.; Bensimhon, Daniel R.; Wasserman, Karlman; Hansen, James E.; Houmard, Joseph A.; Annex, Brian H.; Kraus, William E.

2009-01-01

Although both capillary density and peak oxygen consumption (V̇o2) improve with exercise training, it is difficult to find a relationship between these two measures. It has been suggested that peak V̇o2 may be more related to central hemodynamics than to the oxidative potential of skeletal muscle, which may account for this observation. We hypothesized that change in a measure of submaximal performance, anaerobic threshold, might be related to change in skeletal muscle capillary density, a marker of oxidative potential in muscle, with training. Due to baseline differences among these variables, we also hypothesized that relationships might be sex specific. A group of 21 subjects completed an inactive control period, whereas 28 subjects (17 men and 11 women) participated in a 6-mo high-intensity exercise program. All subjects were sedentary, overweight, and dyslipidemic. Potential relationships were assessed between change in capillary density with both change in V̇o2 at peak and at anaerobic threshold with exercise training. All variables and relationships were assessed for sex-specific effects. Change in peak V̇o2 was not related to change in capillary density after exercise training in either sex. Men had a positive correlation between change in V̇o2 at anaerobic threshold and change in capillary density with exercise training (r = 0.635; P < 0.01), whereas women had an inverse relationship (r = −0.636; P < 0.05) between the change in these variables. These findings suggest that, although enhanced capillary density is associated with training-induced improvements in submaximal performance in men, this relationship is different in women. PMID:19164774

Integrated multiple patch-clamp array chip via lateral cell trapping junctions

NASA Astrophysics Data System (ADS)

Seo, J.; Ionescu-Zanetti, C.; Diamond, J.; Lal, R.; Lee, L. P.

2004-03-01

We present an integrated multiple patch-clamp array chip by utilizing lateral cell trapping junctions. The intersectional design of a microfluidic network provides multiple cell addressing and manipulation sites for efficient electrophysiological measurements at a number of patch sites. The patch pores consist of openings in the sidewall of a main fluidic channel, and a membrane patch is drawn into a smaller horizontal channel. This device geometry not only minimizes capacitive coupling between the cell reservoir and the patch channel, but also allows simultaneous optical and electrical measurements of ion channel proteins. Evidence of the hydrodynamic placement of mammalian cells at the patch sites as well as measurements of patch sealing resistance is presented. Device fabrication is based on micromolding of polydimethylsiloxane, thus allowing inexpensive mass production of disposable high-throughput biochips.

Evaluation of atomic pressure in the multiple time-step integration algorithm.

PubMed

Andoh, Yoshimichi; Yoshii, Noriyuki; Yamada, Atsushi; Okazaki, Susumu

2017-04-15

In molecular dynamics (MD) calculations, reduction in calculation time per MD loop is essential. A multiple time-step (MTS) integration algorithm, the RESPA (Tuckerman and Berne, J. Chem. Phys. 1992, 97, 1990-2001), enables reductions in calculation time by decreasing the frequency of time-consuming long-range interaction calculations. However, the RESPA MTS algorithm involves uncertainties in evaluating the atomic interaction-based pressure (i.e., atomic pressure) of systems with and without holonomic constraints. It is not clear which intermediate forces and constraint forces in the MTS integration procedure should be used to calculate the atomic pressure. In this article, we propose a series of equations to evaluate the atomic pressure in the RESPA MTS integration procedure on the basis of its equivalence to the Velocity-Verlet integration procedure with a single time step (STS). The equations guarantee time-reversibility even for the system with holonomic constrants. Furthermore, we generalize the equations to both (i) arbitrary number of inner time steps and (ii) arbitrary number of force components (RESPA levels). The atomic pressure calculated by our equations with the MTS integration shows excellent agreement with the reference value with the STS, whereas pressures calculated using the conventional ad hoc equations deviated from it. Our equations can be extended straightforwardly to the MTS integration algorithm for the isothermal NVT and isothermal-isobaric NPT ensembles. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Capillary Electrophoresis - Optical Detection Systems

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

Sepaniak, M. J.

2001-08-06

Molecular recognition systems are developed via molecular modeling and synthesis to enhance separation performance in capillary electrophoresis and optical detection methods for capillary electrophoresis. The underpinning theme of our work is the rational design and development of molecular recognition systems in chemical separations and analysis. There have been, however, some subtle and exciting shifts in our research paradigm during this period. Specifically, we have moved from mostly separations research to a good balance between separations and spectroscopic detection for separations. This shift is based on our perception that the pressing research challenges and needs in capillary electrophoresis and electrokinetic chromatographymore » relate to the persistent detection and flow rate reproducibility limitations of these techniques (see page 1 of the accompanying Renewal Application for further discussion). In most of our work molecular recognition reagents are employed to provide selectivity and enhance performance. Also, an emerging trend is the use of these reagents with specially-prepared nano-scale materials. Although not part of our DOE BES-supported work, the modeling and synthesis of new receptors has indirectly supported the development of novel microcantilevers-based MEMS for the sensing of vapor and liquid phase analytes. This fortuitous overlap is briefly covered in this report. Several of the more significant publications that have resulted from our work are appended. To facilitate brevity we refer to these publications liberally in this progress report. Reference is also made to very recent work in the Background and Preliminary Studies Section of the Renewal Application.« less

Integration of multiple determinants in the neuronal computation of economic values.

PubMed

Raghuraman, Anantha P; Padoa-Schioppa, Camillo

2014-08-27

Economic goods may vary on multiple dimensions (determinants). A central conjecture in decision neuroscience is that choices between goods are made by comparing subjective values computed through the integration of all relevant determinants. Previous work identified three groups of neurons in the orbitofrontal cortex (OFC) of monkeys engaged in economic choices: (1) offer value cells, which encode the value of individual offers; (2) chosen value cells, which encode the value of the chosen good; and (3) chosen juice cells, which encode the identity of the chosen good. In principle, these populations could be sufficient to generate a decision. Critically, previous work did not assess whether offer value cells (the putative input to the decision) indeed encode subjective values as opposed to physical properties of the goods, and/or whether offer value cells integrate multiple determinants. To address these issues, we recorded from the OFC while monkeys chose between risky outcomes. Confirming previous observations, three populations of neurons encoded the value of individual offers, the value of the chosen option, and the value-independent choice outcome. The activity of both offer value cells and chosen value cells encoded values defined by the integration of juice quantity and probability. Furthermore, both populations reflected the subjective risk attitude of the animals. We also found additional groups of neurons encoding the risk associated with a particular option, the risky nature of the chosen option, and whether the trial outcome was positive or negative. These results provide substantial support for the conjecture described above and for the involvement of OFC in good-based decisions. Copyright © 2014 the authors 0270-6474/14/3311583-21$15.00/0.

Statistical intensity variation analysis for rapid volumetric imaging of capillary network flux

PubMed Central

Lee, Jonghwan; Jiang, James Y.; Wu, Weicheng; Lesage, Frederic; Boas, David A.

2014-01-01

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. PMID:24761298

PARAMETER ESTIMATION OF TWO-FLUID CAPILLARY PRESSURE-SATURATION AND PERMEABILITY FUNCTIONS

EPA Science Inventory

Capillary pressure and permeability functions are crucial to the quantitative description of subsurface flow and transport. Earlier work has demonstrated the feasibility of using the inverse parameter estimation approach in determining these functions if both capillary pressure ...

Smart Phase Tuning in Microwave Photonic Integrated Circuits Toward Automated Frequency Multiplication by Design

NASA Astrophysics Data System (ADS)

Nabavi, N.

2018-07-01

The author investigates the monitoring methods for fine adjustment of the previously proposed on-chip architecture for frequency multiplication and translation of harmonics by design. Digital signal processing (DSP) algorithms are utilized to create an optimized microwave photonic integrated circuit functionality toward automated frequency multiplication. The implemented DSP algorithms are formed on discrete Fourier transform and optimization-based algorithms (Greedy and gradient-based algorithms), which are analytically derived and numerically compared based on the accuracy and speed of convergence criteria.

Nonaqueous capillary electrophoresis of dextromethorphan and its metabolites.

PubMed

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.

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

PubMed

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 < 0.001). In univariate analysis, both capillary 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 < 0.001). In Cox regression, adjustment for capillary 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.

Analytical model for describing ion guiding through capillaries in insulating polymers

NASA Astrophysics Data System (ADS)

Liu, Shi-Dong; Zhao, Yong-Tao; Wang, Yu-Yu; N, Stolterfoht; Cheng, Rui; Zhou, Xian-Ming; Xu, Hu-Shan; Xiao, Guo-Qing

2015-08-01

An analytical description for guiding of ions through nanocapillaries is given on the basis of previous work. The current entering into the capillary is assumed to be divided into a current fraction transmitted through the capillary, a current fraction flowing away via the capillary conductivity and a current fraction remaining within the capillary, which is responsible for its charge-up. The discharging current is assumed to be governed by the Frenkel-Poole process. At higher conductivities the analytical model shows a blocking of the ion transmission, which is in agreement with recent simulations. Also, it is shown that ion blocking observed in experiments is well reproduced by the analytical formula. Furthermore, the asymptotic fraction of transmitted ions is determined. Apart from the key controlling parameter (charge-to-energy ratio), the ratio of the capillary conductivity to the incident current is included in the model. Differences resulting from the nonlinear and linear limits of the Frenkel-Poole discharge are pointed out. Project supported by the Major State Basic Research Development Program of China (Grant No. 2010CB832902) and the National Natural Science Foundation of China (Grant Nos. 11275241, 11275238, 11105192, and 11375034).

Improvement in Retinal Capillary Rarefaction After Valsartan Treatment in Hypertensive Patients.

PubMed

Jumar, Agnes; Harazny, Joanna M; Ott, Christian; Kistner, Iris; Friedrich, Stefanie; Schmieder, Roland E

2016-11-01

Decreased capillary density influences vascular resistance and perfusion. The authors aimed to investigate the influence of the renin-angiotensin receptor blocker valsartan on retinal capillary rarefaction in hypertensive patients. Retinal vascular parameters were measured noninvasively and in vivo by scanning laser Doppler flowmetry before and after 4 weeks of treatment with valsartan in 95 patients with hypertension stage 1 or 2 and compared with 55 healthy individuals. Retinal capillary rarefaction was determined with the parameters intercapillary distance (ICD) and capillary area (CapA). In hypertensive patients, ICD decreased (23.4±5.5 μm vs 21.5±5.6 μm, P<.001) and CapA increased (1564±621 vs 1776±795, P=.001) after valsartan treatment compared with baseline. Compared with healthy normotensive controls (ICD 20.2±4.2 μm, CapA 1821±652), untreated hypertensive patients showed greater ICD (P<.001) and smaller CapA (P=.019), whereas treated hypertensive patients showed no difference in ICD (P=.126) and CapA (P=.728). Therapy with valsartan for 4 weeks diminished capillary rarefaction in hypertensive patients. © 2016 Wiley Periodicals, Inc.

An Integrative Framework for the Analysis of Multiple and Multimodal Representations for Meaning-Making in Science Education

ERIC Educational Resources Information Center

Tang, Kok-Sing; Delgado, Cesar; Moje, Elizabeth Birr

2014-01-01

This paper presents an integrative framework for analyzing science meaning-making with representations. It integrates the research on multiple representations and multimodal representations by identifying and leveraging the differences in their units of analysis in two dimensions: timescale and compositional grain size. Timescale considers the…

A simple expression for quantifying bacterial chemotaxis using capillary assay data: application to the analysis of enhanced chemotactic responses from growth-limited cultures.

PubMed

Ford, R M; Lauffenburger, D A

1992-05-01

An individual cell-based mathematical model of Rivero et al. provides a framework for determining values of the chemotactic sensitivity coefficient chi 0, an intrinsic cell population parameter that characterizes the chemotactic response of bacterial populations. This coefficient can theoretically relate the swimming behavior of individual cells to the resulting migration of a bacterial population. When this model is applied to the commonly used capillary assay, an approximate solution can be obtained for a particular range of chemotactic strengths yielding a very simple analytical expression for estimating the value of chi 0, [formula: see text] from measurements of cell accumulation in the capillary, N, when attractant uptake is negligible. A0 and A infinity are the dimensionless attractant concentrations initially present at the mouth of the capillary and far into the capillary, respectively, which are scaled by Kd, the effective dissociation constant for receptor-attractant binding. D is the attractant diffusivity, and mu is the cell random motility coefficient. NRM is the cell accumulation in the capillary in the absence of an attractant gradient, from which mu can be determined independently as mu = (pi/4t)(NRM/pi r2bc)2, with r the capillary tube radius and bc the bacterial density initially in the chamber. When attractant uptake is significant, a slightly more involved procedure requiring a simple numerical integration becomes necessary. As an example, we apply this approach to quantitatively characterize, in terms of the chemotactic sensitivity coefficient chi 0, data from Terracciano indicating enhanced chemotactic responses of Escherichia coli to galactose when cultured under growth-limiting galactose levels in a chemostat.

CAPILLARY ELECTROPHORETIC BEHAVIOR OF SEVEN SULFONYLUREAS

EPA Science Inventory

The electrophoretic behavior of bensulfuron Me, sulfometuron Me, nicosulfuron (Accent), chlorimuron Et, thifensulfuron Me (Harmony), metsulfuron Me, and chlorsulfuron was studied under capillary zone electrophoresis (CZE) and micellar electrokinetic chromatography (MEKC) conditio...

Investigation of energy dissipation due to contact angle hysteresis in capillary effect

NASA Astrophysics Data System (ADS)

Athukorallage, Bhagya; Iyer, Ram

2016-06-01

Capillary action or Capillarity is the ability of a liquid to flow in narrow spaces without the assistance of, and in opposition to, external forces like gravity. Three effects contribute to capillary action, namely, adhesion of the liquid to the walls of the confining solid; meniscus formation; and low Reynolds number fluid flow. We investigate the dissipation of energy during one cycle of capillary action, when the liquid volume inside a capillary tube first increases and subsequently decreases while assuming quasi-static motion. The quasi-static assumption allows us to focus on the wetting phenomenon of the solid wall by the liquid and the formation of the meniscus. It is well known that the motion of a liquid on an non-ideal surface involves the expenditure of energy due to contact angle hysteresis. In this paper, we derive the equations for the menisci and the flow rules for the change of the contact angles for a liquid column in a capillary tube at a constant temperature and volume by minimizing the Helmholtz free energy using calculus of variations. We describe the numerical solution of these equations and present results from computations for the case of a capillary tube with 1 mm diameter.

Capillary transit time heterogeneity and flow-metabolism coupling after traumatic brain injury

PubMed Central

Østergaard, Leif; Engedal, Thorbjørn S; Aamand, Rasmus; Mikkelsen, Ronni; Iversen, Nina K; Anzabi, Maryam; Næss-Schmidt, Erhard T; Drasbek, Kim R; Bay, Vibeke; Blicher, Jakob U; Tietze, Anna; Mikkelsen, Irene K; Hansen, Brian; Jespersen, Sune N; Juul, Niels; Sørensen, Jens CH; Rasmussen, Mads

2014-01-01

Most patients who die after traumatic brain injury (TBI) show evidence of ischemic brain damage. Nevertheless, it has proven difficult to demonstrate cerebral ischemia in TBI patients. After TBI, both global and localized changes in cerebral blood flow (CBF) are observed, depending on the extent of diffuse brain swelling and the size and location of contusions and hematoma. These changes vary considerably over time, with most TBI patients showing reduced CBF during the first 12 hours after injury, then hyperperfusion, and in some patients vasospasms before CBF eventually normalizes. This apparent neurovascular uncoupling has been ascribed to mitochondrial dysfunction, hindered oxygen diffusion into tissue, or microthrombosis. Capillary compression by astrocytic endfeet swelling is observed in biopsies acquired from TBI patients. In animal models, elevated intracranial pressure compresses capillaries, causing redistribution of capillary flows into patterns argued to cause functional shunting of oxygenated blood through the capillary bed. We used a biophysical model of oxygen transport in tissue to examine how capillary flow disturbances may contribute to the profound changes in CBF after TBI. The analysis suggests that elevated capillary transit time heterogeneity can cause critical reductions in oxygen availability in the absence of ‘classic' ischemia. We discuss diagnostic and therapeutic consequences of these predictions. PMID:25052556

SELECTIVE TRACE ENRICHMENT BY IMMUNOAFFINITY CAPILLARY ELECTROCHROMATOGRAPHY ON-LINE WITH CAPILLARY ZONE ELECTROPHORESIS - LASER-INDUCED FLUORESCENCE

EPA Science Inventory

Limited by the lack of a sensitive, universal detector, many capillary-based liquid-phase separation techniques might benefit from techniques that overcome modest concentration sensitivity by preconcentrating large injection volumes. The work presented employs selective solid-ph...