Patch-clamp amplifiers on a chip

PubMed Central

Weerakoon, Pujitha; Culurciello, Eugenio; Yang, Youshan; Santos-Sacchi, Joseph; Kindlmann, Peter J.; Sigworth, Fred J.

2010-01-01

We present the first, fully-integrated, two-channel implementation of a patch-clamp measurement system. With this “PatchChip” two simultaneous whole-cell recordings can be obtained with rms noise of 8 pA in a 10 kHz bandwidth. The capacitance and series-resistance of the electrode can be compensated up to 10 pF and 100 MΩ respectively under computer control. Recordings of hERG and Nav 1.7 currents demonstrate the system's capabilities, which are on par with large, commercial patch-clamp instrumentation. By reducing patch-clamp amplifiers to a millimeter size micro-chip, this work paves the way to the realization of massively-parallel, high-throughput patch-clamp systems for drug screening and ion-channel research. The PatchChip is implemented in a 0.5 μm silicon-on-sapphire process; its size is 3 × 3 mm2 and the power consumption is 5 mW per channel with a 3.3 V power supply. PMID:20637803

Force-controlled patch clamp of beating cardiac cells.

PubMed

Ossola, Dario; Amarouch, Mohamed-Yassine; Behr, Pascal; Vörös, János; Abriel, Hugues; Zambelli, Tomaso

2015-03-11

From its invention in the 1970s, the patch clamp technique is the gold standard in electrophysiology research and drug screening because it is the only tool enabling accurate investigation of voltage-gated ion channels, which are responsible for action potentials. Because of its key role in drug screening, innovation efforts are being made to reduce its complexity toward more automated systems. While some of these new approaches are being adopted in pharmaceutical companies, conventional patch-clamp remains unmatched in fundamental research due to its versatility. Here, we merged the patch clamp and atomic force microscope (AFM) techniques, thus equipping the patch-clamp with the sensitive AFM force control. This was possible using the FluidFM, a force-controlled nanopipette based on microchanneled AFM cantilevers. First, the compatibility of the system with patch-clamp electronics and its ability to record the activity of voltage-gated ion channels in whole-cell configuration was demonstrated with sodium (NaV1.5) channels. Second, we showed the feasibility of simultaneous recording of membrane current and force development during contraction of isolated cardiomyocytes. Force feedback allowed for a gentle and stable contact between AFM tip and cell membrane enabling serial patch clamping and injection without apparent cell damage.

Plasma Chamber Restraints in Ignitor and Relevant Disruption Analysis

NASA Astrophysics Data System (ADS)

Gasparotto, M.; Cucchiaro, A.; Capriccioli, A.; Celentano, G.; Rita, C.; Roccella, M.; Macco, B.; Micheli, I.; Ferrari, G.; Orlandi, S.; Coppi, B.

2000-10-01

The plasmas chamber (PC) of Ignitor is made of 12 D-shaped toroidal sectors of Inconel 625 welded together by automatic remote equipment. The thickness of the inboard wall is 17 mm while the middle and outboard walls are 26 mm thick. The PC is supported through the ports by the C-Clamp structure of the toroidal magnet. The main function of the PC supports is to resist the vertical and radial electromagnetic loads and to allow for free movement under thermal loads while providing electrical insulation from the C-Clamps and cryostat. The largest estimated loads are due to a Vertical Displacement Event (VDE) disruption that is followed by a thermal quench and then by the current quench. The vertical supports involve a connection of each radial port to the C-Clamp structure by a link system that withstands the calculated loads. The radial supports resist, with high stiffness, the centripetal and centrifugal forces. The end flange of each radial port is connected to the C-Clamp structure by a clamping sleeve device. The clamping sleeves are hydraulically operated to provide locking during discharge. The clamping sleeves of the radial support system have been validated by an appropriate series of tests.

46 CFR 28.335 - Fuel systems.

Code of Federal Regulations, 2014 CFR

2014-10-01

... (2) Nonmetallic flexible hose is acceptable but must— (i) Not be used in lengths of more than 30... reinforced with wire braid. (iv) Be fitted with suitable, corrosion resistant, compression fittings; and (v) Be installed with two clamps at each end of the hose, if designed for use with clamps. Clamps must...

46 CFR 28.335 - Fuel systems.

Code of Federal Regulations, 2010 CFR

2010-10-01

... (2) Nonmetallic flexible hose is acceptable but must— (i) Not be used in lengths of more than 30... reinforced with wire braid. (iv) Be fitted with suitable, corrosion resistant, compression fittings; and (v) Be installed with two clamps at each end of the hose, if designed for use with clamps. Clamps must...

46 CFR 28.335 - Fuel systems.

Code of Federal Regulations, 2012 CFR

2012-10-01

... (2) Nonmetallic flexible hose is acceptable but must— (i) Not be used in lengths of more than 30... reinforced with wire braid. (iv) Be fitted with suitable, corrosion resistant, compression fittings; and (v) Be installed with two clamps at each end of the hose, if designed for use with clamps. Clamps must...

46 CFR 28.335 - Fuel systems.

Code of Federal Regulations, 2013 CFR

2013-10-01

... (2) Nonmetallic flexible hose is acceptable but must— (i) Not be used in lengths of more than 30... reinforced with wire braid. (iv) Be fitted with suitable, corrosion resistant, compression fittings; and (v) Be installed with two clamps at each end of the hose, if designed for use with clamps. Clamps must...

Flowmeter evaluation for on-orbit operations

NASA Technical Reports Server (NTRS)

Baird, R. S.

1988-01-01

Various flowmetering concepts were flow tested to characterize the relative capabilities and limitations for on-orbit fluid-transfer operations. Performance results and basic operating principles of each flowmetering concept tested are summarized, and basic considerations required to select the best flowmeter(s) for fluid system application are discussed. Concepts tested were clamp-on ultrasonic, area averaging ultrasonic, offset ultrasonic, coriolis mass, vortex shedding, universal venturi tube, turbine, bearingless turbine, turbine/turbine differential-pressure hybrid, dragbody, and dragbody/turbine hybrid flowmeters. Fluid system flowmeter selection considerations discussed are flowmeter performance, fluid operating conditions, systems operating environments, flowmeter packaging, flowmeter maintenance, and flowmeter technology. No one flowmetering concept tested was shown to be best for all on-orbit fluid systems.

Pipe support

DOEpatents

Pollono, Louis P.

1979-01-01

A pipe support for high temperature, thin-walled piping runs such as those used in nuclear systems. A section of the pipe to be supported is encircled by a tubular inner member comprised of two walls with an annular space therebetween. Compacted load-bearing thermal insulation is encapsulated within the annular space, and the inner member is clamped to the pipe by a constant clamping force split-ring clamp. The clamp may be connected to pipe hangers which provide desired support for the pipe.

33 CFR 183.532 - Clips, straps, and hose clamps.

Code of Federal Regulations, 2010 CFR

2010-07-01

... (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Fuel Systems Equipment Standards § 183.532 Clips... under § 183.590, a hose clamp installed on a fuel line system requiring metallic fuel lines or “USCG...

Effects of Imperfect Dynamic Clamp: Computational and Experimental Results

PubMed Central

Bettencourt, Jonathan C.; Lillis, Kyle P.; White, John A.

2008-01-01

In the dynamic clamp technique, a typically nonlinear feedback system delivers electrical current to an excitable cell that represents the actions of “virtual” ion channels (e.g., channels that are gated by local membrane potential or by electrical activity in neighboring biological or virtual neurons). Since the conception of this technique, there have been a number of different implementations of dynamic clamp systems, each with differing levels of flexibility and performance. Embedded hardware-based systems typically offer feedback that is very fast and precisely timed, but these systems are often expensive and sometimes inflexible. PC-based systems, on the other hand, allow the user to write software that defines an arbitrarily complex feedback system, but real-time performance in PC-based systems can be deteriorated by imperfect real-time performance. Here we systematically evaluate the performance requirements for artificial dynamic clamp knock-in of transient sodium and delayed rectifier potassium conductances. Specifically we examine the effects of controller time step duration, differential equation integration method, jitter (variability in time step), and latency (the time lag from reading inputs to updating outputs). Each of these control system flaws is artificially introduced in both simulated and real dynamic clamp experiments. We demonstrate that each of these errors affect dynamic clamp accuracy in a way that depends on the time constants and stiffness of the differential equations being solved. In simulations, time steps above 0.2 ms lead to catastrophic alteration of spike shape, but the frequency-vs.-current relationship is much more robust. Latency (the part of the time step that occurs between measuring membrane potential and injecting re-calculated membrane current) is a crucial factor as well. Experimental data are substantially more sensitive to inaccuracies than simulated data. PMID:18076999

Substrate clamping effects on irreversible domain wall dynamics in lead zirconate titanate thin films.

PubMed

Griggio, F; Jesse, S; Kumar, A; Ovchinnikov, O; Kim, H; Jackson, T N; Damjanovic, D; Kalinin, S V; Trolier-McKinstry, S

2012-04-13

The role of long-range strain interactions on domain wall dynamics is explored through macroscopic and local measurements of nonlinear behavior in mechanically clamped and released polycrystalline lead zirconate-titanate (PZT) films. Released films show a dramatic change in the global dielectric nonlinearity and its frequency dependence as a function of mechanical clamping. Furthermore, we observe a transition from strong clustering of the nonlinear response for the clamped case to almost uniform nonlinearity for the released film. This behavior is ascribed to increased mobility of domain walls. These results suggest the dominant role of collective strain interactions mediated by the local and global mechanical boundary conditions on the domain wall dynamics. The work presented in this Letter demonstrates that measurements on clamped films may considerably underestimate the piezoelectric coefficients and coupling constants of released structures used in microelectromechanical systems, energy harvesting systems, and microrobots.

Launch Lock Assemblies Including Axial Gap Amplification Devices and Spacecraft Isolation Systems Including the Same

NASA Technical Reports Server (NTRS)

Barber, Tim Daniel (Inventor); Hindle, Timothy (Inventor); Young, Ken (Inventor); Davis, Torey (Inventor)

2014-01-01

Embodiments of a launch lock assembly are provided, as are embodiments of a spacecraft isolation system including one or more launch lock assemblies. In one embodiment, the launch lock assembly includes first and second mount pieces, a releasable clamp device, and an axial gap amplification device. The releasable clamp device normally maintains the first and second mount pieces in clamped engagement; and, when actuated, releases the first and second mount pieces from clamped engagement to allow relative axial motion there between. The axial gap amplification device normally residing in a blocking position wherein the gap amplification device obstructs relative axial motion between the first and second mount pieces. The axial gap amplification device moves into a non-blocking position when the first and second mount pieces are released from clamped engagement to increase the range of axial motion between the first and second mount pieces.

Piezoresistive cantilever force-clamp system

PubMed Central

Park, Sung-Jin; Petzold, Bryan C.; Goodman, Miriam B.; Pruitt, Beth L.

2011-01-01

We present a microelectromechanical device-based tool, namely, a force-clamp system that sets or “clamps” the scaled force and can apply designed loading profiles (e.g., constant, sinusoidal) of a desired magnitude. The system implements a piezoresistive cantilever as a force sensor and the built-in capacitive sensor of a piezoelectric actuator as a displacement sensor, such that sample indentation depth can be directly calculated from the force and displacement signals. A programmable real-time controller operating at 100 kHz feedback calculates the driving voltage of the actuator. The system has two distinct modes: a force-clamp mode that controls the force applied to a sample and a displacement-clamp mode that controls the moving distance of the actuator. We demonstrate that the system has a large dynamic range (sub-nN up to tens of μN force and nm up to tens of μm displacement) in both air and water, and excellent dynamic response (fast response time, <2 ms and large bandwidth, 1 Hz up to 1 kHz). In addition, the system has been specifically designed to be integrated with other instruments such as a microscope with patch-clamp electronics. We demonstrate the capabilities of the system by using it to calibrate the stiffness and sensitivity of an electrostatic actuator and to measure the mechanics of a living, freely moving Caenorhabditis elegans nematode. PMID:21529009

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

Jackrel, Sara L.; Owens, Sarah M.; Gilbert, Jack A.

Plants in terrestrial and aquatic environments contain a diverse microbiome. Yet, the chloroplast and mitochondria organelles of the plant eukaryotic cell originate from free-living cyanobacteria and Rickettsiales. This represents a challenge for sequencing the plant microbiome with universal primers, as ~99% of 16S rRNA sequences may consist of chloroplast and mitochondrial sequences. Peptide nucleic acid clamps offer a potential solution by blocking amplification of host-associated sequences. We assessed the efficacy of chloroplast and mitochondria-blocking clamps against a range of microbial taxa from soil, freshwater and marine environments. While we found that the mitochondrial blocking clamps appear to be a robustmore » method for assessing animal-associated microbiota, Proteobacterial 16S rRNA binds to the chloroplast-blocking clamp, resulting in a strong sequencing bias against this group. We attribute this bias to a conserved 14-bp sequence in the Proteobacteria that matches the 17-bp chloroplast-blocking clamp sequence. By scanning the Greengenes database, we provide a reference list of nearly 1500 taxa that contain this 14-bp sequence, including 48 families such as the Rhodobacteraceae, Phyllobacteriaceae, Rhizobiaceae, Kiloniellaceae and Caulobacteraceae. To determine where these taxa are found in nature, we mapped this taxa reference list against the Earth Microbiome Project database. These taxa are abundant in a variety of environments, particularly aquatic and semiaquatic freshwater and marine habitats. To facilitate informed decisions on effective use of organelle-blocking clamps, we provide a searchable database of microbial taxa in the Greengenes and Silva databases matching various n-mer oligonucleotides of each PNA sequence.« less

Microchip amplifier for in vitro, in vivo, and automated whole cell patch-clamp recording

PubMed Central

Kolb, Ilya; Kodandaramaiah, Suhasa B.; Chubykin, Alexander A.; Yang, Aimei; Bear, Mark F.; Boyden, Edward S.; Forest, Craig R.

2014-01-01

Patch clamping is a gold-standard electrophysiology technique that has the temporal resolution and signal-to-noise ratio capable of reporting single ion channel currents, as well as electrical activity of excitable single cells. Despite its usefulness and decades of development, the amplifiers required for patch clamping are expensive and bulky. This has limited the scalability and throughput of patch clamping for single-ion channel and single-cell analyses. In this work, we have developed a custom patch-clamp amplifier microchip that can be fabricated using standard commercial silicon processes capable of performing both voltage- and current-clamp measurements. A key innovation is the use of nonlinear feedback elements in the voltage-clamp amplifier circuit to convert measured currents into logarithmically encoded voltages, thereby eliminating the need for large high-valued resistors, a factor that has limited previous attempts at integration. Benchtop characterization of the chip shows low levels of current noise [1.1 pA root mean square (rms) over 5 kHz] during voltage-clamp measurements and low levels of voltage noise (8.2 μV rms over 10 kHz) during current-clamp measurements. We demonstrate the ability of the chip to perform both current- and voltage-clamp measurement in vitro in HEK293FT cells and cultured neurons. We also demonstrate its ability to perform in vivo recordings as part of a robotic patch-clamping system. The performance of the patch-clamp amplifier microchip compares favorably with much larger commercial instrumentation, enabling benchtop commoditization, miniaturization, and scalable patch-clamp instrumentation. PMID:25429119

The Piezo Actuator-Driven Pulsed Water Jet System for Minimizing Renal Damage after Off-Clamp Laparoscopic Partial Nephrectomy.

PubMed

Kamiyama, Yoshihiro; Yamashita, Shinichi; Nakagawa, Atsuhiro; Fujii, Shinji; Mitsuzuka, Koji; Kaiho, Yasuhiro; Ito, Akihiro; Abe, Takaaki; Tominaga, Teiji; Arai, Yoichi

2017-09-01

In the setting of partial nephrectomy (PN) for renal cell carcinoma, postoperative renal dysfunction might be caused by surgical procedure. The aim of this study was to clarify the technical safety and renal damage after off-clamp laparoscopic PN (LPN) with a piezo actuator-driven pulsed water jet (ADPJ) system. Eight swine underwent off-clamp LPN with this surgical device, while off-clamp open PN was also performed with radio knife or soft coagulation. The length of the removed kidney was 40 mm, and the renal parenchyma was dissected until the renal calyx became clearly visible. The degree of renal degeneration from the resection surface was compared by Hematoxylin-Eosin staining and immunostaining for 1-methyladenosine, a sensitive marker for the ischemic tissue damage. The mRNA levels of neutrophil gelatinase-associated lipocalin (Ngal), a biomarker for acute kidney injury, were measured by quantitative real-time PCR. Off-clamp LPN with ADPJ system was successfully performed while preserving fine blood vessels and the renal calix with little bleeding. In contrast to other devices, the resection surface obtained with the ADPJ system showed only marginal degree of ischemic changes. Indeed, the expression level of Ngal mRNA was lower in the resection surface obtained with the ADPJ system than that with soft coagulation (p = 0.02). Furthermore, using the excised specimens of renal cell carcinoma, we measured the breaking strength at each site of the human kidney, suggesting the applicability of this ADPJ to clinical trials. In conclusion, off-clamp LPN with the ADPJ system could be safely performed with attenuated renal damage.

Renal functional and perioperative outcomes of off-clamp versus clamped robot-assisted partial nephrectomy: matched cohort study.

PubMed

Tanagho, Youssef S; Bhayani, Sam B; Sandhu, Gurdarshan S; Vaughn, Nicholas P; Nepple, Kenneth G; Figenshau, R Sherburne

2012-10-01

To evaluate the potential benefit of performing off-clamp robot-assisted partial nephrectomy as it relates to renal functional outcomes, while assessing the safety profile of this unconventional surgical approach. Twenty-nine patients who underwent off-clamp robot-assisted partial nephrectomy for suspected renal cell carcinoma at Washington University between March 2008 and September 2011 (group 1) were matched to 29 patients with identical nephrometry scores and comparable baseline renal function who underwent robot-assisted partial nephrectomy with hilar clamping during the same period (group 2). The matched cohorts' perioperative and renal functional outcomes were compared at a mean 9-month follow-up. Mean estimated blood loss was 146.4 mL in group 1, versus 103.9 mL in group 2 (P = .039). Mean hilar clamp time was 0 minutes in group 1 and 14.7 minutes in group 2. No perioperative complications were encountered in group 1; 1 Clavien-2 complication (3.4%) occurred in group 2 (P = 1.000). At 9-month follow-up, mean estimated glomerular filtration rate in group 1 was 79.9 versus 84.8 mL/min/1.73 m(2) preoperatively (P = .013); mean estimated glomerular filtration rate in group 2 was 74.1 versus 85.8 mL/min/1.73 m(2) preoperatively (P < .001). Hence, estimated glomerular filtration rate declined by a mean of 4.9 mL/min/1.73 m(2) in group 1 versus 11.7 mL/min/1.73 m(2) in group 2 (P = .033). Off-clamp robot-assisted partial nephrectomy is associated with a favorable morbidity profile and relatively greater renal functional preservation compared to clamped robot-assisted partial nephrectomy. Nevertheless, the benefit is small in renal functional terms and may have very limited clinical relevance. Copyright © 2012 Elsevier Inc. All rights reserved.

Launch Lock Assemblies with Reduced Preload and Spacecraft Isolation Systems Including the Same

NASA Technical Reports Server (NTRS)

Barber, Tim Daniel (Inventor); Young, Ken (Inventor); Hindle, Timothy (Inventor)

2016-01-01

Launch lock assemblies with reduced preload are provided. The launch lock assembly comprises first and second mount pieces, a releasable clamp device, and a pair of retracting assemblies. Each retracting assembly comprises a pair of toothed members having interacting toothed surfaces. The releasable clamp device normally maintains the first and second mount pieces in clamped engagement. When the releasable clamp device is actuated, the first and second mount pieces are released from clamped engagement and one toothed member of each retracting assembly moves in an opposite direction relative to the other one toothed member of the other retracting assembly to define an axial gap on each side of the first mount piece.

Internal V-Band Clamp

DOEpatents

Vaughn, Mark R.; Hafenrichter, Everett S.; Chapa, Agapito C.; Harris, Steven M.; Martinez, Marcus J.; Baty, Roy S.

2006-02-28

A system for clamping two tubular members together in an end-to-end relationship uses a split ring with a V-shaped outer rim that can engage a clamping surface on each member. The split ring has a relaxed closed state where the ends of the ring are adjacent and the outside diameter of the split ring is less than the minimum inside diameter of the members at their ends. The members are clamped when the split ring is spread into an elastically stretched position where the ring rim is pressed tightly against the interior surfaces of the members. Mechanisms are provided for removing the spreader so the split ring will return to the relaxed state, releasing the clamped members.

Industrializing electrophysiology: HT automated patch clamp on SyncroPatch® 96 using instant frozen cells.

PubMed

Polonchuk, Liudmila

2014-01-01

Patch-clamping is a powerful technique for investigating the ion channel function and regulation. However, its low throughput hampered profiling of large compound series in early drug development. Fortunately, automation has revolutionized the area of experimental electrophysiology over the past decade. Whereas the first automated patch-clamp instruments using the planar patch-clamp technology demonstrated rather a moderate throughput, few second-generation automated platforms recently launched by various companies have significantly increased ability to form a high number of high-resistance seals. Among them is SyncroPatch(®) 96 (Nanion Technologies GmbH, Munich, Germany), a fully automated giga-seal patch-clamp system with the highest throughput on the market. By recording from up to 96 cells simultaneously, the SyncroPatch(®) 96 allows to substantially increase throughput without compromising data quality. This chapter describes features of the innovative automated electrophysiology system and protocols used for a successful transfer of the established hERG assay to this high-throughput automated platform.

Development and Testing of a Post-Installable Deepwater Monitoring System Using Fiber-Optic Sensors

NASA Technical Reports Server (NTRS)

Seaman, Calvin H.; Brower, David V.; Le, Suy Q.; Tang, Henry H.

2015-01-01

This paper addresses the design and development of a fiber-optic monitoring system that can be deployed on existing deepwater risers and flowlines; and provides a summary of test article fabrication and the subsequent laboratory testing performed at the National Aeronautics and Space Administration-Johnson Space Center (NASA-JSC). A major challenge of a post-installed instrumentation system is to ensure adequate coupling between the instruments and the riser or flowline of interest. This work investigates the sensor coupling for pipelines that are suspended in a water column (from topside platform to seabed) using a fiber-optic sensor clamp and subsea bonding adhesive. The study involved the design, fabrication, and test of several prototype clamps that contained fiber-optic sensors. A mold was produced by NASA using 3-D printing methods that allowed the casting of polyurethane clamp test articles to accommodate 4-inch and 8-inch diameter pipes. The prototype clamps were installed with a subsea adhesive in a "wet" environment and then tested in the NASA Structures Test Laboratory (STL). The tension, compression, and bending test data showed that the prototype sensor clamps achieved good structural coupling, and could provide high quality strain measurement for active monitoring.

A hydrophilic polymer based microfluidic system with planar patch clamp electrode array for electrophysiological measurement from cells.

PubMed

Xu, Baojian; Ye, WeiWei; Zhang, Yu; Shi, JingYu; Chan, ChunYu; Yao, XiaoQiang; Yang, Mo

2014-03-15

This paper presents a microfluidic planar patch clamp system based on a hydrophilic polymer poly(ethylene glycol) diacrylate (PEGDA) for whole cell current recording. The whole chip is fabricated by UV-assisted molding method for both microfluidic channel structure and planar electrode partition. This hydrophilic patch clamp chip has demonstrated a relatively high gigaseal success rate of 44% without surface modification compared with PDMS based patch clamp devices. This chip also shows a capability of rapid intracellular and extracellular solution exchange with high stability of gigaseals. The capillary flow kinetic experiments demonstrate that the flow rates of PEGDA microfluidic channels are around two orders of magnitude greater than those for PDMS-glass channels with the same channel dimensions. This hydrophilic polymer based patch clamp chips have significant advantages over current PDMS elastomer based systems such as no need for surface modification, much higher success rate of cell gigaseals and rapid solution exchange with stable cell gigaseals. Our results indicate the potential of these devices to serve as useful tools for pharmaceutical screening and biosensing tasks. © 2013 Elsevier B.V. All rights reserved.

Application of active electrode compensation to perform continuous voltage-clamp recordings with sharp microelectrodes.

PubMed

Gómez-González, J F; Destexhe, A; Bal, T

2014-10-01

Electrophysiological recordings of single neurons in brain tissues are very common in neuroscience. Glass microelectrodes filled with an electrolyte are used to impale the cell membrane in order to record the membrane potential or to inject current. Their high resistance induces a high voltage drop when passing current and it is essential to correct the voltage measurements. In particular, for voltage clamping, the traditional alternatives are two-electrode voltage-clamp technique or discontinuous single electrode voltage-clamp (dSEVC). Nevertheless, it is generally difficult to impale two electrodes in a same neuron and the switching frequency is limited to low frequencies in the case of dSEVC. We present a novel fully computer-implemented alternative to perform continuous voltage-clamp recordings with a single sharp-electrode. To reach such voltage-clamp recordings, we combine an active electrode compensation algorithm (AEC) with a digital controller (AECVC). We applied two types of control-systems: a linear controller (proportional plus integrative controller) and a model-based controller (optimal control). We compared the performance of the two methods to dSEVC using a dynamic model cell and experiments in brain slices. The AECVC method provides an entirely digital method to perform continuous recording and smooth switching between voltage-clamp, current clamp or dynamic-clamp configurations without introducing artifacts.

Clamp-Crushing versus stapler hepatectomy for transection of the parenchyma in elective hepatic resection (CRUNSH) - A randomized controlled trial (NCT01049607)

PubMed Central

2011-01-01

Background Hepatic resection is still associated with significant morbidity. Although the period of parenchymal transection presents a crucial step during the operation, uncertainty persists regarding the optimal technique of transection. It was the aim of the present randomized controlled trial to evaluate the efficacy and safety of hepatic resection using the technique of stapler hepatectomy compared to the simple clamp-crushing technique. Methods/Design The CRUNSH Trial is a prospective randomized controlled single-center trial with a two-group parallel design. Patients scheduled for elective hepatic resection without extrahepatic resection at the Department of General-, Visceral- and Transplantation Surgery, University of Heidelberg are enrolled into the trial and randomized intraoperatively to hepatic resection by the clamp-crushing technique and stapler hepatectomy, respectively. The primary endpoint is total intraoperative blood loss. A set of general and surgical variables are documented as secondary endpoints. Patients and outcome-assessors are blinded for the treatment intervention. Discussion The CRUNSH Trial is the first randomized controlled trial to evaluate efficacy and safety of stapler hepatectomy compared to the clamp-crushing technique for parenchymal transection during elective hepatic resection. Trial Registration ClinicalTrials.gov: NCT01049607 PMID:21888669

A miniaturized planar patch-clamp system for transportable use.

PubMed

Boussaoud, Adrien; Fonteille, Isabelle; Collier, Guilhem; Kermarrec, Frédérique; Vermont, Fabien; Tresallet, Eric; De Waard, Michel; Arnoult, Christophe; Picollet-D'hahan, Nathalie

2012-02-15

In the last decade, planar patch-clamp (PPC) has emerged as an innovative technology allowing parallel recordings of cellular electrophysiological activity on planar substrates. If PPC is widely adopted by the pharmaceutical sector, it remains poorly extended to other areas (i.e. environment and safety organizations) probably because of the large, expensive and non-easily transportable format of those commercial equipments. The present work describes for the first time a new compact and transportable planar patch-clamp system (named Toxint'patch or TIP, for Toxin detection with integrated patch-clamp) focusing on environmental matters and meant to be used in coastal laboratories, for direct on-site monitoring of the seawater and shellfish quality. The TIP system incorporates silicon chips tailored to monitor cellular ionic currents from cultured cells stably expressing a phycotoxin molecular target. The functionality of this novel briefcase-sized PPC system is described in terms of fluidic control, electronic performances with amplifying and filtering boards and of user interface for data acquisition and control implemented on a computer. Copyright © 2011 Elsevier B.V. All rights reserved.

Cell-Detection Technique for Automated Patch Clamping

NASA Technical Reports Server (NTRS)

McDowell, Mark; Gray, Elizabeth

2008-01-01

A unique and customizable machinevision and image-data-processing technique has been developed for use in automated identification of cells that are optimal for patch clamping. [Patch clamping (in which patch electrodes are pressed against cell membranes) is an electrophysiological technique widely applied for the study of ion channels, and of membrane proteins that regulate the flow of ions across the membranes. Patch clamping is used in many biological research fields such as neurobiology, pharmacology, and molecular biology.] While there exist several hardware techniques for automated patch clamping of cells, very few of those techniques incorporate machine vision for locating cells that are ideal subjects for patch clamping. In contrast, the present technique is embodied in a machine-vision algorithm that, in practical application, enables the user to identify good and bad cells for patch clamping in an image captured by a charge-coupled-device (CCD) camera attached to a microscope, within a processing time of one second. Hence, the present technique can save time, thereby increasing efficiency and reducing cost. The present technique involves the utilization of cell-feature metrics to accurately make decisions on the degree to which individual cells are "good" or "bad" candidates for patch clamping. These metrics include position coordinates (x,y) in the image plane, major-axis length, minor-axis length, area, elongation, roundness, smoothness, angle of orientation, and degree of inclusion in the field of view. The present technique does not require any special hardware beyond commercially available, off-the-shelf patch-clamping hardware: A standard patchclamping microscope system with an attached CCD camera, a personal computer with an imagedata- processing board, and some experience in utilizing imagedata- processing software are all that are needed. A cell image is first captured by the microscope CCD camera and image-data-processing board, then the image data are analyzed by software that implements the present machine-vision technique. This analysis results in the identification of cells that are "good" candidates for patch clamping (see figure). Once a "good" cell is identified, a patch clamp can be effected by an automated patchclamping apparatus or by a human operator. This technique has been shown to enable reliable identification of "good" and "bad" candidate cells for patch clamping. The ultimate goal in further development of this technique is to combine artificial-intelligence processing with instrumentation and controls in order to produce a complete "turnkey" automated patch-clamping system capable of accurately and reliably patch clamping cells with a minimum intervention by a human operator. Moreover, this technique can be adapted to virtually any cellular-analysis procedure that includes repetitive operation of microscope hardware by a human.

Development of a Post-Installed Deepwater Monitoring System

NASA Technical Reports Server (NTRS)

Seaman, C.; Brower, D. V.; Tang, H.; Le, S.

2015-01-01

A monitoring system that can be deployed on already existing deep water risers and flowlines has been developed. This paper describes the design concepts and testing that was performed in developing the monitoring system. A major challenge of a post-installed instrumentation system is to ensure adequate coupling is achieved between the instruments and the riser or flowline. This work investigates the sensor coupling for pipelines that are suspended in both the water column (from topside platform to the seabed) and for those that are located directly on the seabed. These different environments have resulted in two sensor attachment methods: (1) subsea adhesive sensor clamp design and (2) a friction surface sensor attachment method. This paper presents the adhesive attachment method. The monitoring elements consist of fiber optic sensors that are encased in a polyurethane clamp. With a subsea adhesive, the clamp can be installed by divers in shallow depths or by use of an ROV for deeper applications. The NASA Johnson Space Center was initially involved in the selection and testing of subsea adhesives. It was determined that up to 75 percent of the bonding strength could be achieved with the adhesive from optimal dry bonding versus bonding in submerged sea water environments. The next phase of the study involved the design, fabrication, and testing of several prototype clamps that contained the fiber optic sensors. A mold was produced by NASA using 3-D printing methods that allowed the fabrication of subscale test articles that would accommodate 4-inch and 8-inch diameter pipes. The clamps were installed with adhesive in a "wet" environment on the pipe test articles and tested in the NASA Structures Test Laboratory. The tension/compression and bending tests showed that the prototype sensor clamps achieved good coupling, and could provide high quality strain measurement for active monitoring.

Photovoltaic module mounting system

DOEpatents

Miros, Robert H. J.; Mittan, Margaret Birmingham; Seery, Martin N; Holland, Rodney H

2012-09-18

A solar array mounting system having unique installation, load distribution, and grounding features, and which is adaptable for mounting solar panels having no external frame. The solar array mounting system includes flexible, pedestal-style feet and structural links connected in a grid formation on the mounting surface. The photovoltaic modules are secured in place via the use of attachment clamps that grip the edge of the typically glass substrate. The panel mounting clamps are then held in place by tilt brackets and/or mid-link brackets that provide fixation for the clamps and align the solar panels at a tilt to the horizontal mounting surface. The tilt brackets are held in place atop the flexible feet and connected link members thus creating a complete mounting structure.

Photovoltaic module mounting system

DOEpatents

Miros, Robert H. J. [Fairfax, CA; Mittan, Margaret Birmingham [Oakland, CA; Seery, Martin N [San Rafael, CA; Holland, Rodney H [Novato, CA

2012-04-17

A solar array mounting system having unique installation, load distribution, and grounding features, and which is adaptable for mounting solar panels having no external frame. The solar array mounting system includes flexible, pedestal-style feet and structural links connected in a grid formation on the mounting surface. The photovoltaic modules are secured in place via the use of attachment clamps that grip the edge of the typically glass substrate. The panel mounting clamps are then held in place by tilt brackets and/or mid-link brackets that provide fixation for the clamps and align the solar panels at a tilt to the horizontal mounting surface. The tilt brackets are held in place atop the flexible feet and connected link members thus creating a complete mounting structure.

Actuator development for the Instrument Pointing System (IPS)

NASA Technical Reports Server (NTRS)

Suttner, K.

1984-01-01

The mechanisms of the instrument pointing system (IPS) are described. Particular emphasis is placed on the actuators which are necessary for operating the IPS. The actuators are described as follows: (1) two linear actuators that clamp the gimbals down during ascent and descent; (2) two linear actuators that attach the payload to the IPS during the mission, and release it into the payload clamps; (3) one rotational actuator that opens and closes the payload clamps; and (4) three identical drive units that represent the three orthogonal gimbal axes and are the prime movers for pointing. Design features, manufacturing problems, test performance, and results are presented.

Catch and Patch: A Pipette-Based Approach for Automating Patch Clamp That Enables Cell Selection and Fast Compound Application.

PubMed

Danker, Timm; Braun, Franziska; Silbernagl, Nikole; Guenther, Elke

2016-03-01

Manual patch clamp, the gold standard of electrophysiology, represents a powerful and versatile toolbox to stimulate, modulate, and record ion channel activity from membrane fragments and whole cells. The electrophysiological readout can be combined with fluorescent or optogenetic methods and allows for ultrafast solution exchanges using specialized microfluidic tools. A hallmark of manual patch clamp is the intentional selection of individual cells for recording, often an essential prerequisite to generate meaningful data. So far, available automation solutions rely on random cell usage in the closed environment of a chip and thus sacrifice much of this versatility by design. To parallelize and automate the traditional patch clamp technique while perpetuating the full versatility of the method, we developed an approach to automation, which is based on active cell handling and targeted electrode placement rather than on random processes. This is achieved through an automated pipette positioning system, which guides the tips of recording pipettes with micrometer precision to a microfluidic cell handling device. Using a patch pipette array mounted on a conventional micromanipulator, our automated patch clamp process mimics the original manual patch clamp as closely as possible, yet achieving a configuration where recordings are obtained from many patch electrodes in parallel. In addition, our implementation is extensible by design to allow the easy integration of specialized equipment such as ultrafast compound application tools. The resulting system offers fully automated patch clamp on purposely selected cells and combines high-quality gigaseal recordings with solution switching in the millisecond timescale.

Protein associations in DnaA-ATP hydrolysis mediated by the Hda-replicase clamp complex.

PubMed

Su'etsugu, Masayuki; Shimuta, Toh-Ru; Ishida, Takuma; Kawakami, Hironori; Katayama, Tsutomu

2005-02-25

In Escherichia coli, the activity of ATP-bound DnaA protein in initiating chromosomal replication is negatively controlled in a replication-coordinated manner. The RIDA (regulatory inactivation of DnaA) system promotes DnaA-ATP hydrolysis to produce the inactivated form DnaA-ADP in a manner depending on the Hda protein and the DNA-loaded form of the beta-sliding clamp, a subunit of the replicase holoenzyme. A highly functional form of Hda was purified and shown to form a homodimer in solution, and two Hda dimers were found to associate with a single clamp molecule. Purified mutant Hda proteins were used in a staged in vitro RIDA system followed by a pull-down assay to show that Hda-clamp binding is a prerequisite for DnaA-ATP hydrolysis and that binding is mediated by an Hda N-terminal motif. Arg(168) in the AAA(+) Box VII motif of Hda plays a role in stable homodimer formation and in DnaA-ATP hydrolysis, but not in clamp binding. Furthermore, the DnaA N-terminal domain is required for the functional interaction of DnaA with the Hda-clamp complex. Single cells contain approximately 50 Hda dimers, consistent with the results of in vitro experiments. These findings and the features of AAA(+) proteins, including DnaA, suggest the following model. DnaA-ATP is hydrolyzed at a binding interface between the AAA(+) domains of DnaA and Hda; the DnaA N-terminal domain supports this interaction; and the interaction of DnaA-ATP with the Hda-clamp complex occurs in a catalytic mode.

How Technique Is Changing Science.

ERIC Educational Resources Information Center

Hall, Stephen

1992-01-01

The author describes specific examples of the use of technology in science such as fiberoptic spectroscopy to observe galaxies and conduct three-dimensional maps of the universe. Adduces the following examples of technology influencing scientific investigations: gene cloning, gene sequencing, radioimmunoassays, patch-clamping of neurons, scanning…

A Dynamic Clamp on Every Rig

PubMed Central

2017-01-01

Abstract The dynamic clamp should be a standard part of every cellular electrophysiologist’s toolbox. That it is not, even 25 years after its introduction, comes down to three issues: money, the disruption that adding dynamic clamp to an existing electrophysiology rig entails, and the technical prowess required of experimenters. These have been valid and limiting issues in the past, but no longer. Technological advances associated with the so-called maker movement render them moot. We demonstrate this by implementing a fast (∼100 kHz) dynamic clamp system using an inexpensive microcontroller (Teensy 3.6). The overall cost of the system is less than USD$100, and assembling it requires no prior electronics experience. Modifying it—for example, to add Hodgkin–Huxley-style conductances—requires no prior programming experience. The system works together with existing electrophysiology data acquisition systems (for Macintosh, Windows, and Linux); it does not attempt to supplant them. Moreover, the process of assembling, modifying, and using the system constitutes a useful pedagogical exercise for students and researchers with no background but an interest in electronics and programming. We demonstrate the system’s utility by implementing conductances as fast as a transient sodium conductance and as complex as the Ornstein–Uhlenbeck conductances of the “point conductance” model of synaptic background activity. PMID:29085905

Mechanical shear and tensile characteristics of selected biomass stems

USDA-ARS?s Scientific Manuscript database

Mechanical characteristics (stress and energy of tensile and shear modes) of selected biomass stems, such as big bluestem, bromegrass, and Barlow wheat were determined. A high capacity MTI-100K universal testing machine attached with standard tensile clamps and designed fabricated double-shear devic...

Mechanism of opening a sliding clamp

PubMed Central

Douma, Lauren G.; Yu, Kevin K.; England, Jennifer K.

2017-01-01

Abstract Clamp loaders load ring-shaped sliding clamps onto DNA where the clamps serve as processivity factors for DNA polymerases. In the first stage of clamp loading, clamp loaders bind and stabilize clamps in an open conformation, and in the second stage, clamp loaders place the open clamps around DNA so that the clamps encircle DNA. Here, the mechanism of the initial clamp opening stage is investigated. Mutations were introduced into the Escherichia coli β-sliding clamp that destabilize the dimer interface to determine whether the formation of an open clamp loader–clamp complex is dependent on spontaneous clamp opening events. In other work, we showed that mutation of a positively charged Arg residue at the β-dimer interface and high NaCl concentrations destabilize the clamp, but neither facilitates the formation of an open clamp loader–clamp complex in experiments presented here. Clamp opening reactions could be fit to a minimal three-step ‘bind-open-lock’ model in which the clamp loader binds a closed clamp, the clamp opens, and subsequent conformational rearrangements ‘lock’ the clamp loader–clamp complex in a stable open conformation. Our results support a model in which the E. coli clamp loader actively opens the β-sliding clamp. PMID:28973453

Sampling system and method

DOEpatents

Decker, David L; Lyles, Brad F; Purcell, Richard G; Hershey, Ronald Lee

2014-05-20

An apparatus and method for supporting a tubing bundle during installation or removal. The apparatus includes a clamp for securing the tubing bundle to an external wireline. The method includes deploying the tubing bundle and wireline together, The tubing bundle is periodically secured to the wireline using a clamp.

33 CFR 183.560 - Hose clamps: Installation.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Hose clamps: Installation. 183.560 Section 183.560 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Fuel Systems Manufacturer Requirements § 183.560...

Double-stator electromagnetic pump having alignment ring and spine assembly

DOEpatents

Fanning, Alan Wayne; Olich, Eugene Ellsworth; Dahl, Leslie Roy; Patel, Mahadeo Ratilal

1997-01-01

A support structure for clamping the inner coils and inner lamination rings of an inner stator column of an electromagnetic induction pump to prevent damaging vibration. A spine assembly, including a base plate, a center post and a plurality of ribs, serves as the structural frame for the inner stator. Stacked alignment rings provide structure to the lamination rings and locate them concentrically around the spine assembly central axis. The alignment rings are made of a material having a high thermal expansion coefficient to compensate for the lower expansion of the lamination rings and, overall, provide an approximate match to the expansion of the inner flow duct. The net result is that the radial clamping provided by the duct around the stator iron is maintained (approximately) over a range of temperatures and operating conditions. Axial clamping of the inner stator structure is achieved via tie rods which run through grooves in the ribs and engage the base plate at the bottom of the inner stator and engage a clamping plate at the top. Slender tie rods and a flexible clamping plate are used to provide compliance in the axial clamping system to accommodate differential thermal growth (axially) between the tie rods and lamination ring elements without losing clamping force.

Double-stator electromagnetic pump having alignment ring and spine assembly

DOEpatents

Fanning, A.W.; Olich, E.E.; Dahl, L.R.; Patel, M.R.

1997-06-24

A support structure for clamping the inner coils and inner lamination rings of an inner stator column of an electromagnetic induction pump to prevent damaging vibration is disclosed. A spine assembly, including a base plate, a center post and a plurality of ribs, serves as the structural frame for the inner stator. Stacked alignment rings provide structure to the lamination rings and locate them concentrically around the spine assembly central axis. The alignment rings are made of a material having a high thermal expansion coefficient to compensate for the lower expansion of the lamination rings and, overall, provide an approximate match to the expansion of the inner flow duct. The net result is that the radial clamping provided by the duct around the stator iron is maintained (approximately) over a range of temperatures and operating conditions. Axial clamping of the inner stator structure is achieved via tie rods which run through grooves in the ribs and engage the base plate at the bottom of the inner stator and engage a clamping plate at the top. Slender tie rods and a flexible clamping plate are used to provide compliance in the axial clamping system to accommodate differential thermal growth (axially) between the tie rods and lamination ring elements without losing clamping force. 12 figs.

Down-hole periodic seismic generator

DOEpatents

Hardee, H.C.; Hills, R.G.; Striker, R.P.

1982-10-28

A down hole periodic seismic generator system is disclosed for transmitting variable frequency, predominantly shear-wave vibration into earth strata surrounding a borehole. The system comprises a unitary housing operably connected to a well head by support and electrical cabling and contains clamping apparatus for selectively clamping the housing to the walls of the borehole. The system further comprises a variable speed pneumatic oscillator and a self-contained pneumatic reservoir for producing a frequency-swept seismic output over a discrete frequency range.

Advanced downhole periodic seismic generator

DOEpatents

Hardee, Harry C.; Hills, Richard G.; Striker, Richard P.

1991-07-16

An advanced downhole periodic seismic generator system for transmitting variable frequency, predominantly shear-wave vibration into earth strata surrounding a borehole. The system comprises a unitary housing operably connected to a well head by support and electrical cabling and contains clamping apparatus for selectively clamping the housing to the walls of the borehole. The system further comprises a variable speed pneumatic oscillator and a self-contained pneumatic reservoir for producing a frequency-swept seismic output over a discrete frequency range.

Down hole periodic seismic generator

DOEpatents

Hardee, Harry C.; Hills, Richard G.; Striker, Richard P.

1989-01-01

A down hole periodic seismic generator system for transmitting variable frequency, predominantly shear-wave vibration into earth strata surrounding a borehole. The system comprises a unitary housing operably connected to a well head by support and electrical cabling and contains clamping apparatus for selectively clamping the housing to the walls of the borehole. The system further comprises a variable speed pneumatic oscillator and a self-contained pneumatic reservoir for producing a frequency-swept seismic output over a discrete frequency range.

An In Vivo Study of Low-Dose Intra-Articular Tranexamic Acid Application with Prolonged Clamping Drain Method in Total Knee Replacement: Clinical Efficacy and Safety.

PubMed

Sa-ngasoongsong, Paphon; Chanplakorn, Pongsthorn; Wongsak, Siwadol; Uthadorn, Krisorn; Panpikoon, Tanapong; Jittorntam, Paisan; Aryurachai, Katcharin; Angchaisukisiri, Pantap; Kawinwonggowit, Viroj

2015-01-01

Recently, combined intra-articular tranexamic acid (IA-TXA) injection with clamping drain method showed efficacy for blood loss and transfusion reduction in total knee replacement (TKR). However, until now, none of previous studies revealed the effect of this technique on pharmacokinetics, coagulation, and fibrinolysis. An experimental study was conducted, during 2011-2012, in 30 patients undergoing unilateral TKR. Patients received IA-TXA application and then were allocated into six groups regarding clamping drain duration (2-, 4-, 6-, 8-, 10-, and 12-hours). Blood and drainage fluid were collected to measure tranexamic acid (TXA) level and related coagulation and fibrinolytic markers. Postoperative complication was followed for one year. There was no significant difference of serum TXA level at 2 hour and 24 hour among groups (p < 0.05). Serum TXA level at time of clamp release was significantly different among groups with the highest level at 2 hour (p < 0.0001). There was no significant difference of TXA level in drainage fluid, postoperative blood loss, blood transfusion, and postoperative complications (p < 0.05). Low-dose IA-TXA application in TKR with prolonged clamping drain method is a safe and effective blood conservative technique with only minimal systemic absorption and without significant increase in systemic absorption over time.

Artery cross-clamping during laparoscopic vascular surgeries; a computational tactile sensing approach.

PubMed

Pahlavan, Pedram; Najarian, Siamak; Afshari, Elnaz; Moini, Majid

2013-01-01

Artificial palpation is one of the most valuable achievements of artificial tactile sensing approach that can be used in various fields of medicine and more specifically in surgery. These techniques cause different surgical maneuvers to be done more precisely and noninvasively. In this study, considering the present problems and limitations of cross-clamping an artery during laparoscopic vascular surgeries, a new tactile sensory system will be introduced.Having imitated surgeon's palpation during open vascular surgeries and modeled it conceptually, the optimal amount of the total angular displacement of each robot joint in order to cross-clamping an artery without damaging to the artery surrounding tissues will be calculated. The elastic governing equation of contact occurred between the tactile sensor placed on the first link of the robot and the surrounding tissues around the artery were developed. A finite element model is coupled with genetic algorithm optimization method so that the normal stress and displacements in contact surface of the robot and artery's surrounding tissues would be minimized. Thus, reliability and accuracy of artificial tactile sensing method in artery cross-clamping will be demonstrated. Finally, the functional principles of the new tactile system capable of cross-clamping an artery during laparoscopic surgeries will be presented.

Modular shield

DOEpatents

Snyder, Keith W.

2002-01-01

A modular system for containing projectiles has a sheet of material including at least a polycarbonate layer held by a metal frame having a straight frame member corresponding to each straight edge of the sheet. Each frame member has a U-shaped shield channel covering and holding a straight edge of the sheet and an adjacent U-shaped clamp channel rigidly held against the shield channel. A flexible gasket separates each sheet edge from its respective shield channel; and each frame member is fastened to each adjacent frame member only by clamps extending between adjacent clamp channels.

Integration of autopatching with automated pipette and cell detection in vitro

PubMed Central

Wu (吴秋雨), Qiuyu; Kolb, Ilya; Callahan, Brendan M.; Su, Zhaolun; Stoy, William; Kodandaramaiah, Suhasa B.; Neve, Rachael; Zeng, Hongkui; Boyden, Edward S.; Forest, Craig R.

2016-01-01

Patch clamp is the main technique for measuring electrical properties of individual cells. Since its discovery in 1976 by Neher and Sakmann, patch clamp has been instrumental in broadening our understanding of the fundamental properties of ion channels and synapses in neurons. The conventional patch-clamp method requires manual, precise positioning of a glass micropipette against the cell membrane of a visually identified target neuron. Subsequently, a tight “gigaseal” connection between the pipette and the cell membrane is established, and suction is applied to establish the whole cell patch configuration to perform electrophysiological recordings. This procedure is repeated manually for each individual cell, making it labor intensive and time consuming. In this article we describe the development of a new automatic patch-clamp system for brain slices, which integrates all steps of the patch-clamp process: image acquisition through a microscope, computer vision-based identification of a patch pipette and fluorescently labeled neurons, micromanipulator control, and automated patching. We validated our system in brain slices from wild-type and transgenic mice expressing channelrhodopsin 2 under the Thy1 promoter (line 18) or injected with a herpes simplex virus-expressing archaerhodopsin, ArchT. Our computer vision-based algorithm makes the fluorescent cell detection and targeting user independent. Compared with manual patching, our system is superior in both success rate and average trial duration. It provides more reliable trial-to-trial control of the patching process and improves reproducibility of experiments. PMID:27385800

Use of CYPRES™ cutters with a Kevlar clamp band for hold-down and release of the Icarus De-Orbit Sail payload on TechDemoSat-1

NASA Astrophysics Data System (ADS)

Kingston, J.; Hobbs, S.; Roberts, P.; Juanes-Vallejo, C.; Robinson, F.; Sewell, R.; Snapir, B.; Llop, J. Virgili; Patel, M.

2014-07-01

TechDemoSat-1 is a UK-funded technology demonstration satellite, carrying 8 payloads provided by UK organisations, which is due to be launched in the first quarter of 2014. Cranfield University has supplied a De-Orbit Sail (DOS) payload to allow the mission to comply with end-of-life debris mitigation guidelines. The payload provides a passive, simple, and low-cost means of mitigating debris proliferation in Low Earth Orbit, by enhancing spacecraft aerodynamic drag at end-of-life and reducing time to natural orbital decay and re-entry. This paper describes the use of small commercial electro-explosive devices (EEDs), produced for use as parachute tether-cutters in reserve chute deployment systems, as low-cost but high-reliability release mechanisms for space applications. A testing campaign, including thermal vacuum and mechanical vibration, is described, which demonstrates the suitability of these CYPRES™ cutters, with a flexible Kevlar clamp band, for use as a hold-down and release mechanism (HDRM) for a deployable de-orbit sail. The HDRM is designed to be three-failure-tolerant, highly reliable, yet simple and low-cost.

VOLTAGE CLAMP BEHAVIOR OF IRON-NITRIC ACID SYSTEM AS COMPARED WITH THAT OF NERVE MEMBRANE

PubMed Central

Tasaki, I.; Bak, A. F.

1959-01-01

The current-voltage relation for the surface layer of an iron wire immersed in nitric acid was investigated by the voltage clamp technique. Comparing the phase of nitric acid to the axoplasm and the metallic phase to the external fluid medium for the nerve fiber, a striking analogy was found between the voltage clamp behavior of the iron-nitric acid system and that of the nerve membrane. The current voltage curve was found to consist of three parts: (a) a straight line representing the behavior of the resting (passive) membrane, (b) a straight line representing the fully excited (active) state, and (c) an intermediate zone connecting (a) and (b). It was shown that in the intermediate zone, the surface of iron consisted of a fully active patch (or patches) surrounded by a remaining resting area. The phenomenon corresponding to "repetitive firing of responses under voltage clamp" in the nerve membrane was demonstrated in the intermediate zone. The behavior of the cobalt electrode system was also investigated by the same technique. An attempt was made to interpret the phenomenon of initiation and abolition of an active potential on the basis of the thermodynamics of irreversible processes. PMID:13654740

77 FR 51720 - Airworthiness Directives; The Boeing Company Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-27

... clamps installed within the left environmental cooling systems (ECS) bay, which could allow wiring to... support clamps installed within the left ECS bay, which is a flammable leakage zone. Use of incorrect wire... bundle within the left side ECS bay, and corrective actions if necessary. Corrective actions include...

Robotic Automation of In Vivo Two-Photon Targeted Whole-Cell Patch-Clamp Electrophysiology.

PubMed

Annecchino, Luca A; Morris, Alexander R; Copeland, Caroline S; Agabi, Oshiorenoya E; Chadderton, Paul; Schultz, Simon R

2017-08-30

Whole-cell patch-clamp electrophysiological recording is a powerful technique for studying cellular function. While in vivo patch-clamp recording has recently benefited from automation, it is normally performed "blind," meaning that throughput for sampling some genetically or morphologically defined cell types is unacceptably low. One solution to this problem is to use two-photon microscopy to target fluorescently labeled neurons. Combining this with robotic automation is difficult, however, as micropipette penetration induces tissue deformation, moving target cells from their initial location. Here we describe a platform for automated two-photon targeted patch-clamp recording, which solves this problem by making use of a closed loop visual servo algorithm. Our system keeps the target cell in focus while iteratively adjusting the pipette approach trajectory to compensate for tissue motion. We demonstrate platform validation with patch-clamp recordings from a variety of cells in the mouse neocortex and cerebellum. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

The computational structural mechanics testbed architecture. Volume 1: The language

NASA Technical Reports Server (NTRS)

Felippa, Carlos A.

1988-01-01

This is the first set of five volumes which describe the software architecture for the Computational Structural Mechanics Testbed. Derived from NICE, an integrated software system developed at Lockheed Palo Alto Research Laboratory, the architecture is composed of the command language CLAMP, the command language interpreter CLIP, and the data manager GAL. Volumes 1, 2, and 3 (NASA CR's 178384, 178385, and 178386, respectively) describe CLAMP and CLIP, and the CLIP-processor interface. Volumes 4 and 5 (NASA CR's 178387 and 178388, respectively) describe GAL and its low-level I/O. CLAMP, an acronym for Command Language for Applied Mechanics Processors, is designed to control the flow of execution of processors written for NICE. Volume 1 presents the basic elements of the CLAMP language and is intended for all users.

Modular Cooling Components

NASA Technical Reports Server (NTRS)

Eastman, G. Yale; Dussinger, Peter M.; Hartenstine, John R.

1994-01-01

Three modular heat-transfer components designed for use together or separately. Simple mechanical connections facilitate assembly of these and related heat-transfer components into cooling systems of various configurations, such as to cool laboratory equipment rearranged for different experiments. Components are clamp-on cold plate, cold plate attached to flexible heat pipe, and thermal-bus receptacle. Clamp-on cold plate moved to any convenient location for attachment of equipment cooled by it, then clamped onto thermal bus. Heat from equipment conducted through plate and into coolant. Thermal-bus receptacle integral with thermal bus. Includes part of thermal bus to which clamp-on cold plate attached, plus tapered socket into which condenser end of flexible heat pipe plugged. Thermal-bus receptacle includes heat-pipe wick structure using coolant in bus to enhance transfer of heat from cold plate.

The logic of DNA replication in double-stranded DNA viruses: insights from global analysis of viral genomes.

PubMed

Kazlauskas, Darius; Krupovic, Mart; Venclovas, Česlovas

2016-06-02

Genomic DNA replication is a complex process that involves multiple proteins. Cellular DNA replication systems are broadly classified into only two types, bacterial and archaeo-eukaryotic. In contrast, double-stranded (ds) DNA viruses feature a much broader diversity of DNA replication machineries. Viruses differ greatly in both completeness and composition of their sets of DNA replication proteins. In this study, we explored whether there are common patterns underlying this extreme diversity. We identified and analyzed all major functional groups of DNA replication proteins in all available proteomes of dsDNA viruses. Our results show that some proteins are common to viruses infecting all domains of life and likely represent components of the ancestral core set. These include B-family polymerases, SF3 helicases, archaeo-eukaryotic primases, clamps and clamp loaders of the archaeo-eukaryotic type, RNase H and ATP-dependent DNA ligases. We also discovered a clear correlation between genome size and self-sufficiency of viral DNA replication, the unanticipated dominance of replicative helicases and pervasive functional associations among certain groups of DNA replication proteins. Altogether, our results provide a comprehensive view on the diversity and evolution of replication systems in the DNA virome and uncover fundamental principles underlying the orchestration of viral DNA replication. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

Effects of delayed cord clamping on the third stage of labour, maternal haematological parameters and acid-base status in fetuses at term.

PubMed

De Paco, Catalina; Herrera, Javier; Garcia, Carolina; Corbalán, Shiana; Arteaga, Alicia; Pertegal, Miriam; Checa, Rosario; Prieto, María Teresa; Nieto, Aníbal; Delgado, Juan Luis

2016-12-01

To compare the time in the third stage of labour, differences in maternal hematologic parameters 48h after birth and acid-base status in the umbilical cord between the early cord clamping (ECC) and delayed cord clamping (DCC). 97 healthy pregnancies at term and a spontaneous vertex delivery at Clinic University Hospital "Virgen de la Arrixaca" (Murcia, Spain), were randomized to ECC group (<10s post-delivery) or to DCC group (2min post-delivery). Duration of the third stage of labour was measured. Samples for acid-base status were taken both from the umbilical artery and vein. Blood samples were taken from the mothers 48h after birth. No statistical differences were found in the time of the third stage of labour (p=0.35). No statiscally significant differences were found between the number of red cells (p=0.25), hemoglobin (p=0.08) or hematocrit (p=0.15) in mothers. Umbilical acid-base status or gas analysis did not show any differences between the two groups CONCLUSIONS: Delayed cord clamping does not affect significantly the time of the third stage of labour. It does not show either any effect on the hematological parameters in the mother 48h after birth. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

The effect of direct renin inhibition alone and in combination with ACE inhibition on endothelial function, arterial stiffness, and renal function in type 1 diabetes.

PubMed

Cherney, David Z I; Scholey, James W; Jiang, Shan; Har, Ronnie; Lai, Vesta; Sochett, Etienne B; Reich, Heather N

2012-11-01

Diabetes is associated with renin-angiotensin system (RAS) activation, leading to renal and systemic vascular dysfunction that contribute to end-organ injury and significant morbidity. RAS blockade with ACE inhibitors reduces, but does not abolish, RAS effects. Accordingly, our aim was to determine if direct renin inhibition alone, and in combination with an ACE inhibitor, corrects early hemodynamic abnormalities associated with type 1 diabetes. Arterial stiffness (augmentation index), flow-mediated vasodilatation (FMD), and renal hemodynamic function (inulin and paraaminohippurate clearance) were measured at baseline under clamped euglycemic and hyperglycemic conditions (n = 21). Measures were repeated after 4 weeks of aliskiren therapy and again after aliskiren plus ramipril. Blood pressure-lowering effects of aliskiren were similar during clamped euglycemia and hyperglycemia. Combination therapy augmented this effect under both glycemic conditions (P = 0.0005). Aliskiren reduced arterial stiffness under clamped euglycemic and hyperglycemic conditions, and the effects were augmented by dual RAS blockade (-3.4 ± 11.2 to -8.0 ± 11.5 to -14.3 ± 8.4%, respectively, during euglycemia, P = 0.0001). During clamped euglycemia, aliskiren increased FMD; dual therapy exaggerated this effect (5.1 ± 3.3 to 7.5 ± 3.0 to 10.8 ± 3.5%, repeated-measures ANOVA, P = 0.0001). Aliskiren monotherapy caused renal vasodilatation during clamped hyperglycemia only. In contrast, dual therapy augmented renal vasodilatory effects during clamped euglycemia and hyperglycemia. In patients with uncomplicated type 1 diabetes, aliskiren-based dual RAS blockade is associated with greater arterial compliance, FMD, and renal vasodilatation.

Development and Testing of a Friction-Based Post-Installable Sensor for Subsea Fiber-Optic Monitoring System

NASA Technical Reports Server (NTRS)

Bentley, Nicole L.; Brower, David V.; Le, Suy Q.; Seaman, Calvin H.; Tang, Henry H.

2017-01-01

This paper presents the design and development of a friction-based coupling device for a fiber-optic monitoring system that can be deployed on existing subsea structures. This paper provides a summary of the design concept, prototype development, prototype performance testing, and design refinements of the device. The results of the laboratory testing of the first prototype performed at the National Aeronautics and Space Administration (NASA) Johnson Space Center (JSC) are included in this paper. Limitations of the initial design were identified and future design improvements were proposed. These new features will enhance the coupling of the device and improve the monitoring system measurement capabilities. A major challenge of a post-installed instrumentation monitoring system is to ensure adequate coupling between the instruments and the structure of interest for reliable measurements. Friction-based coupling devices have the potential to overcome coupling limitations caused by marine growth and soil contamination on subsea structures, flowlines or risers. The work described in this paper investigates the design of a friction-based coupling device (friction clamp), which is applicable for pipelines and structures that are suspended in the water column and those that are resting on the seabed. The monitoring elements consist of fiber-optic sensors that are bonded to a metal clamshell with a high-friction coating. The friction clamp has a single hinge design to facilitate the operation of the clamp and dual rows of opposing fasteners to distribute the clamping force on the structure. The friction clamp can be installed by divers in shallow depths or by remotely operated vehicles in deep-water applications. NASA-JSC was involved in the selection and testing of the friction coating, and in the design and testing of the prototype clamp device. Four-inch diameter and eight-inch diameter sub-scale friction clamp prototypes were built and tested to evaluate the strain measuring capabilities of the design under different loading scenarios. The testing revealed some limitations of the initial design concept, and subsequent refinements were explored to improve the measurement performance of the system. This study was part of a collaboration between NASA-JSC and Astro Technology, Inc. within a study called Clear Gulf. The primary objective of the Clear Gulf study is to develop advanced instrumentation technologies that will improve operational safety and reduce the risk of hydrocarbon spillage. NASA provided unique insights, expansive test facilities, and technical expertise to advance these technologies that would benefit the environment, the public, and commercial industries.

Development and Testing of a Friction-Based Post-Installable Sensor for Subsea Fiber-Optic Monitoring Systems

NASA Technical Reports Server (NTRS)

Bentley, Nicole; Brower, David; Le, Suy Q.; Seaman, Calvin; Tang, Henry

2017-01-01

This paper presents the design and development of a friction-based coupling device for a fiber-optic monitoring system that can be deployed on existing subsea structures. This paper provides a summary of the design concept, prototype development, prototype performance testing, and design refinements of the device. The results of the laboratory testing of the first prototype performed at the National Aeronautics and Space Administration (NASA) Johnson Space Center (JSC) are included in this paper. Limitations of the initial design were identified and future design improvements were proposed. These new features will enhance the coupling of the device and improve the monitoring system measurement capabilities. A major challenge of a post-installed instrumentation monitoring system is to ensure adequate coupling between the instruments and the structure of interest for reliable measurements. Friction-based coupling devices have the potential to overcome coupling limitations caused by marine growth and soil contamination on subsea structures, flowlines or risers. The work described in this paper investigates the design of a friction-based coupling device (friction clamp), which is applicable for pipelines and structures that are suspended in the water column and those that are resting on the seabed. The monitoring elements consist of fiber-optic sensors that are bonded to a metal clamshell with a high-friction coating. The friction clamp has a single hinge design to facilitate the operation of the clamp and dual rows of opposing fasteners to distribute the clamping force on the structure. The friction clamp can be installed by divers in shallow depths or by remotely operated vehicles in deep-water applications. NASA-JSC was involved in the selection and testing of the friction coating, and in the design and testing of the prototype clamp device. Four-inch diameter and eight-inch diameter sub-scale friction clamp prototypes were built and tested to evaluate the strain measuring capabilities of the design under different loading scenarios. The testing revealed some limitations of the initial design concept, and subsequent refinements were explored to improve the measurement performance of the system. This study was part of a collaboration between NASA-JSC and Astro Technology, Inc. within a study called Clear Gulf. The primary objective of the Clear Gulf study is to develop advanced instrumentation technologies that will improve operational safety and reduce the risk of hydrocarbon spillage. NASA provided unique insights, expansive test facilities, and technical expertise to advance these technologies that would benefit the environment, the public, and commercial industries.

Is early cord clamping, delayed cord clamping or cord milking best?

PubMed

Vatansever, Binay; Demirel, Gamze; Ciler Eren, Elif; Erel, Ozcan; Neselioglu, Salim; Karavar, Hande Nur; Gundogdu, Semra; Ulfer, Gozde; Bahadir, Selcen; Tastekin, Ayhan

2018-04-01

To compare the antioxidant status of three cord clamping procedures (early clamping, delayed clamping and milking) by analyzing the thiol-disulfide balance. This randomized controlled study enrolled 189 term infants who were divided into three groups according to the cord clamping procedure: early clamping, delayed clamping and milking. Blood samples were collected from the umbilical arteries immediately after clamping, and the thiol/disulfide homeostasis was analyzed. The native and total thiol levels were significantly (p < .05) lower in the early cord clamping group compared with the other two groups. The disulfide/total thiol ratio was significantly (p = .026) lower in the delayed cord clamping and milking groups compared with the early clamping groups. Early cord clamping causes the production of more disulfide bonds and lower thiol levels, indicating that oxidation reactions are increased in the early cord clamping procedure compared with the delayed cord clamping and milking procedures. The oxidant capacity is greater with early cord clamping than with delayed clamping or cord milking. Delayed cord clamping or milking are beneficial in neonatal care, and we suggest that they be performed routinely in all deliveries.

Suspension System Provides Independent Translation And Rotation

NASA Technical Reports Server (NTRS)

Heeg, Jennifer

1994-01-01

Spring suspension provides one translational and one rotational degree of freedom. Suspension used to provide for pitching and plunging movements of airfoil in wind tunnel. Translational freedom provided by two thin, flat steel spring tines, clamped at one end to stationary block fixed to ceiling of wind tunnel, and clamped to movable block at other end.

Gas loading apparatus for the Paris-Edinburgh press

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

Bocian, A.; Kamenev, K. V.; Bull, C. L.

2010-09-15

We describe the design and operation of an apparatus for loading gases into the sample volume of the Paris-Edinburgh press at room temperature and high pressure. The system can be used for studies of samples loaded as pure or mixed gases as well as for loading gases as pressure-transmitting media in neutron-scattering experiments. The apparatus consists of a high-pressure vessel and an anvil holder with a clamp mechanism. The vessel, designed to operate at gas pressures of up to 150 MPa, is used for applying the load onto the anvils located inside the clamp. This initial load is sufficient formore » sealing the pressurized gas inside the sample containing gasket. The clamp containing the anvils and the sample is then transferred into the Paris-Edinburgh press by which further load can be applied to the sample. The clamp has apertures for scattered neutron beams and remains in the press for the duration of the experiment. The performance of the gas loading system is illustrated with the results of neutron-diffraction experiments on compressed nitrogen.« less

Synthetic polymers as substrates for a DNA-sliding clamp protein.

PubMed

van Dongen, S F M; Clerx, J; van den Boomen, O I; Pervaiz, M; Trakselis, M A; Ritschel, T; Schoonen, L; Schoenmakers, D C; Nolte, R J M

2018-04-26

The clamp protein (gp45) of the DNA polymerase III of the bacteriophage T4 is known to bind to DNA and stay attached to it in order to facilitate the process of DNA copying by the polymerase. As part of a project aimed at developing new biomimetic data-encoding systems we have investigated the binding of gp45 to synthetic polymers, that is, rigid, helical polyisocyanopeptides. Molecular modelling studies suggest that the clamp protein may interact with the latter polymers. Experiments aimed at verifying these interactions are presented and discussed. © 2018 The Authors Biopolymers Published by Wiley Periodicals, Inc.

Potential Danger of Pre-Pump Clamping on Negative Pressure-Associated Gaseous Microemboli Generation During Extracorporeal Life Support--An In Vitro Study.

PubMed

Wang, Shigang; Chin, Brian J; Gentile, Frank; Kunselman, Allen R; Palanzo, David; Ündar, Akif

2016-01-01

The objectives of this study were to investigate the relationship between revolution speed of a conventional centrifugal pump and negative pressure at the inlet of the pump by clamping the tubing upstream of the pump, and to verify whether negative pressure leads to gaseous microemboli (GME) production in a simulated adult extracorporeal life support (ECLS) system. The experimental circuit, including a Maquet Rotaflow centrifugal pump and a Medos Hilite 7000 LT polymethyl-pentene membrane oxygenator, was primed with packed red blood cells (hematocrit 35%). Negative pressure was created in the circuit by clamping the tubing upstream of the pump for 10 s, and then releasing the clamp. An emboli detection and classification quantifier was used to record GME volume and count at pre-oxygenator and post-oxygenator sites, and pressure and flow rate data were collected using a custom-based data acquisition system. All trials were conducted at 36°C at revolution speeds of 2000-4000 rpm (500 rpm increment). The flow rates were 1092.5-4708.4 mL/min at the revolution speeds of 2000-4000 rpm. Higher revolution speed generated higher negative pressure at the pre-pump site when clamping the tubing upstream of the pump (-108.3 ± 0.1 to -462.0 ± 0.5 mm Hg at 2000-4000 rpm). Moreover, higher negative pressure was associated with a larger number and volume of GME at pre-oxygenator site after de-clamp (GME count 10,573 ± 271 at pre-oxygenator site at 4000 rpm). The results showed that there was a potential danger of delivering GME to the patient when clamping pre-pump tubing during ECLS using a centrifugal pump. Our results warrant further clinical studies to investigate this phenomenon. Copyright © 2015 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

An In Vivo Study of Low-Dose Intra-Articular Tranexamic Acid Application with Prolonged Clamping Drain Method in Total Knee Replacement: Clinical Efficacy and Safety

PubMed Central

Sa-ngasoongsong, Paphon; Chanplakorn, Pongsthorn; Wongsak, Siwadol; Uthadorn, Krisorn; Panpikoon, Tanapong; Jittorntam, Paisan; Aryurachai, Katcharin; Angchaisukisiri, Pantap; Kawinwonggowit, Viroj

2015-01-01

Background. Recently, combined intra-articular tranexamic acid (IA-TXA) injection with clamping drain method showed efficacy for blood loss and transfusion reduction in total knee replacement (TKR). However, until now, none of previous studies revealed the effect of this technique on pharmacokinetics, coagulation, and fibrinolysis. Materials and Methods. An experimental study was conducted, during 2011-2012, in 30 patients undergoing unilateral TKR. Patients received IA-TXA application and then were allocated into six groups regarding clamping drain duration (2-, 4-, 6-, 8-, 10-, and 12-hours). Blood and drainage fluid were collected to measure tranexamic acid (TXA) level and related coagulation and fibrinolytic markers. Postoperative complication was followed for one year. Results. There was no significant difference of serum TXA level at 2 hour and 24 hour among groups (p < 0.05). Serum TXA level at time of clamp release was significantly different among groups with the highest level at 2 hour (p < 0.0001). There was no significant difference of TXA level in drainage fluid, postoperative blood loss, blood transfusion, and postoperative complications (p < 0.05).  Conclusions. Low-dose IA-TXA application in TKR with prolonged clamping drain method is a safe and effective blood conservative technique with only minimal systemic absorption and without significant increase in systemic absorption over time. PMID:26583092

Automated patch clamp on mESC-derived cardiomyocytes for cardiotoxicity prediction.

PubMed

Stoelzle, Sonja; Haythornthwaite, Alison; Kettenhofen, Ralf; Kolossov, Eugen; Bohlen, Heribert; George, Michael; Brüggemann, Andrea; Fertig, Niels

2011-09-01

Cardiovascular side effects are critical in drug development and have frequently led to late-stage project terminations or even drug withdrawal from the market. Physiologically relevant and predictive assays for cardiotoxicity are hence strongly demanded by the pharmaceutical industry. To identify a potential impact of test compounds on ventricular repolarization, typically a variety of ion channels in diverse heterologously expressing cells have to be investigated. Similar to primary cells, in vitro-generated stem cell-derived cardiomyocytes simultaneously express cardiac ion channels. Thus, they more accurately represent the native situation compared with cell lines overexpressing only a single type of ion channel. The aim of this study was to determine if stem cell-derived cardiomyocytes are suited for use in an automated patch clamp system. The authors show recordings of cardiac ion currents as well as action potential recordings in readily available stem cell-derived cardiomyocytes. Besides monitoring inhibitory effects of reference compounds on typical cardiac ion currents, the authors revealed for the first time drug-induced modulation of cardiac action potentials in an automated patch clamp system. The combination of an in vitro cardiac cell model with higher throughput patch clamp screening technology allows for a cost-effective cardiotoxicity prediction in a physiologically relevant cell system.

A comparison of the central nervous system effects of alcohol at pseudo-steady state in Caucasian and expatriate Japanese healthy male volunteers.

PubMed

Zoethout, Remco W M; de Kam, Marieke L; Dahan, Albert; Cohen, Adam F; van Gerven, Joop M A

2012-11-01

In general, Japanese and Caucasians differ in their response to alcohol. To investigate these differences the alcohol clamping method can be used. This strictly controlled infusion regimen provides a reliable tool to study contrasts in central nervous system (CNS) effects and/or alcohol disposition. In this study, twelve Japanese and twelve Caucasian healthy volunteers received two concentrations of intravenous alcohol or placebo using the alcohol clamp. Infusion rates during the steady state phase were used to compare alcohol clearance between the subgroups. Central nervous system (CNS) effects were frequently measured throughout the clamp. On average, significantly lower amounts of alcohol were needed to maintain similar stable concentrations in the Japanese group. However, these differences disappeared when values were corrected for lean body mass. The most pronounced pharmacodynamic differences between the groups were observed on body sway and on the visual analogue scale for subjective alcohol effects, mainly at the highest dose level. The alcohol clamp seems a useful method to compare differences in alcohol metabolism between groups. Some CNS effects of alcohol differed clearly between Japanese and Caucasians, but others did not, even though alcohol levels were stable and similar between the two groups. Copyright © 2012 Elsevier Inc. All rights reserved.

A-Mating-Type Gene Expression Can Drive Clamp Formation in the Bipolar Mushroom Pholiota microspora (Pholiota nameko) ▿

PubMed Central

Yi, Ruirong; Mukaiyama, Hiroyuki; Tachikawa, Takashi; Shimomura, Norihiro; Aimi, Tadanori

2010-01-01

In the bipolar basidiomycete Pholiota microspora, a pair of homeodomain protein genes located at the A-mating-type locus regulates mating compatibility. In the present study, we used a DNA-mediated transformation system in P. microspora to investigate the homeodomain proteins that control the clamp formation. When a single homeodomain protein gene (A3-hox1 or A3-hox2) from the A3 monokaryon strain was transformed into the A4 monokaryon strain, the transformants produced many pseudoclamps but very few clamps. When two homeodomain protein genes (A3-hox1 and A3-hox2) were transformed either separately or together into the A4 monokaryon, the ratio of clamps to the clamplike cells in the transformants was significantly increased to ca. 50%. We therefore concluded that the gene dosage of homeodomain protein genes is important for clamp formation. When the sip promoter was connected to the coding region of A3-hox1 and A3-hox2 and the fused fragments were introduced into NGW19-6 (A4), the transformants achieved more than 85% clamp formation and exhibited two nuclei per cell, similar to the dikaryon (NGW12-163 × NGW19-6). The results of real-time reverse transcription-PCR confirmed that sip promoter activity is greater than that of the native promoter of homeodomain protein genes in P. microspora. Thus, we concluded that nearly 100% clamp formation requires high expression levels of homeodomain protein genes and that altered expression of the A-mating-type genes alone is sufficient to drive true clamp formation. PMID:20453073

Triple bar, high efficiency mechanical sealer

DOEpatents

Pak, Donald J.; Hawkins, Samantha A.; Young, John E.

2013-03-19

A clamp with a bottom clamp bar that has a planar upper surface is provided. The clamp may also include a top clamp bar connected to the bottom clamp bar, and a pressure distribution bar between the top clamp bar and the bottom clamp bar. The pressure distribution bar may have a planar lower surface in facing relation to the upper surface of the bottom clamp bar. An object is capable of being disposed in a clamping region between the upper surface and the lower surface. The width of the planar lower surface may be less than the width of the upper surface within the clamping region. Also, the pressure distribution bar may be capable of being urged away from the top clamp bar and towards the bottom clamp bar.

Sampling system and method

DOEpatents

Decker, David L.; Lyles, Brad F.; Purcell, Richard G.; Hershey, Ronald Lee

2017-03-07

In one embodiment, the present disclosure provides an apparatus and method for supporting a tubing bundle during installation or removal. The apparatus includes a clamp for securing the tubing bundle to an external wireline. In various examples, the clamp is external to the tubing bundle or integral with the tubing bundle. According to one method, a tubing bundle and wireline are deployed together and the tubing bundle periodically secured to the wireline using a clamp. In another embodiment, the present disclosure provides an apparatus and method for coupling conduit segments together. A first pump obtains a sample and transmits it through a first conduit to a reservoir accessible by a second pump. The second pump further conducts the sample from the reservoir through a second conduit. In a specific example, one or more clamps are used to connect the first and/or second conduits to an external wireline.

Thermal conductance of two interface materials and their applications in space systems

NASA Technical Reports Server (NTRS)

Scialdone, J. J.; Clatterbuck, C. H.; Wall, J. L.

1992-01-01

Two polymeric materials, the Cho-Therm 1671 elastomer and the CV-2946 conductive RTV silicone, have been evaluated. Tests were conducted in vacuum and in air, for many clamping pressures, power densities, and as a function of time. Results obtained show that the CV-2946 thermal conductance after 24 hour in vacuum is 0.62 W/sq cm C(4W/sq in C) when clamped with an average pressure of about 350 psi. The maximum conductance of Cho-Therm 1671 is 4.3 W/sq in C at the clamping pressure about 200 psi. After 72 h in vacuum, the conductance reaches a steady 3.4 W/sq in C, independent of clamping pressure. It is concluded that the tightly bolted, torqued fixtures do not buckle or distort and provide an optimum thermal conductance. The fixtures simulating an actual spacecraft configuration suffered severe bowing and separating, which caused considerable degradation of conductance values.

LabPatch, an acquisition and analysis program for patch-clamp electrophysiology.

PubMed

Robinson, T; Thomsen, L; Huizinga, J D

2000-05-01

An acquisition and analysis program, "LabPatch," has been developed for use in patch-clamp research. LabPatch controls any patch-clamp amplifier, acquires and records data, runs voltage protocols, plots and analyzes data, and connects to spreadsheet and database programs. Controls within LabPatch are grouped by function on one screen, much like an oscilloscope front panel. The software is mouse driven, so that the user need only point and click. Finally, the ability to copy data to other programs running in Windows 95/98, and the ability to keep track of experiments using a database, make LabPatch extremely versatile. The system requirements include Windows 95/98, at least a 100-MHz processor and 16 MB RAM, a data acquisition card, digital-to-analog converter, and a patch-clamp amplifier. LabPatch is available free of charge at http://www.fhs.mcmaster.ca/huizinga/.

Post clamp

NASA Technical Reports Server (NTRS)

Ramsey, John K. (Inventor); Meyn, Erwin H. (Inventor)

1990-01-01

A pair of spaced collars are mounted at right angles on a clamp body by retaining rings which enable the collars to rotate with respect to the clamp body. Mounting posts extend through aligned holes in the collars and clamp body. Each collar can be clamped onto the inserted post while the clamp body remains free to rotate about the post and collar. The clamp body is selectively clamped onto each post.

Comparison of the physiological relevance of systemic vs. portal insulin delivery to evaluate whole body glucose flux during an insulin clamp

PubMed Central

Farmer, Tiffany D.; Jenkins, Erin C.; O'Brien, Tracy P.; McCoy, Gregory A.; Havlik, Allison E.; Nass, Erik R.; Nicholson, Wendell E.; Printz, Richard L.

2014-01-01

To understand the underlying pathology of metabolic diseases, such as diabetes, an accurate determination of whole body glucose flux needs to be made by a method that maintains key physiological features. One such feature is a positive differential in insulin concentration between the portal venous and systemic arterial circulation (P/S-IG). P/S-IG during the determination of the relative contribution of liver and extra-liver tissues/organs to whole body glucose flux during an insulin clamp with either systemic (SID) or portal (PID) insulin delivery was examined with insulin infusion rates of 1, 2, and 5 mU·kg−1·min−1 under either euglycemic or hyperglycemic conditions in 6-h-fasted conscious normal rats. A P/S-IG was initially determined with endogenous insulin secretion to exist with a value of 2.07. During an insulin clamp, while inhibiting endogenous insulin secretion by somatostatin, P/S-IG remained at 2.2 with PID, whereas, P/S-IG disappeared completely with SID, which exhibited higher arterial and lower portal insulin levels compared with PID. Consequently, glucose disappearance rates and muscle glycogen synthetic rates were higher, but suppression of endogenous glucose production and liver glycogen synthetic rates were lower with SID compared with PID. When the insulin clamp was performed with SID at 2 and 5 mU·kg−1·min−1 without managing endogenous insulin secretion under euglycemic but not hyperglycemic conditions, endogenous insulin secretion was completely suppressed with SID, and the P/S-IG disappeared. Thus, compared with PID, an insulin clamp with SID underestimates the contribution of liver in response to insulin to whole body glucose flux. PMID:25516552

Steel bridge in interaction with modern slab track fastening systems under various vertical load levels

NASA Astrophysics Data System (ADS)

Stančík, Vojtěch; Ryjáček, Pavel; Vokáč, Miroslav

2017-09-01

In modern slab tracks the continuously welded rail (CWR) is coupled through the fastening system with the substructure. The resulting restriction of expansion movement causes significant rail stress increments, which in the case of extreme loading may cause rail failures. These interaction phenomenon effects are naturally higher on a bridge due to different deformation capabilities of the bridge and the CWR. The presented contribution aims at investigating the state of the art European direct fastening system that is suitable for application on steel bridges. Analysis involves experimental determination of its nonlinear longitudinal interaction parameters under various vertical loads and numerical validation. During experimental procedures a two and a half meter long laboratory sample equipped with four nodes of the Vossloh DFF 300 was tested. There have been checked both DFF 300 modifications using the skl 15 tension clamps and the low resistance skl B15 tension clamps. The effects of clamping force lowering on the interaction parameters have also been investigated. Results are discussed in the paper.

Attitude control of an orbiting space vehicle.

NASA Technical Reports Server (NTRS)

Sutherlin, D. W.; Boland, J. S. , III; Borelli, M. T.

1971-01-01

Study of the normal and clamped modes of operation and dynamic response characteristics of the gimbaled control moment gyro (CMG) designed to fulfill the stringent pointing requirements of the Skylab telescope mount when the spacecraft is under the influence of both external and internal torques. The results indicate that the clamped mode of operation provides a feasible approach for significantly improving the system characteristics.

Development and Testing of a Friction-Based Post-Installable Fiber-Optic Monitoring System for Subsea Applications

NASA Technical Reports Server (NTRS)

Bentley, Nicole L.; Brower, David V.; Le, Suy Q.; Seaman, Calvin H.; Tang, Henry H.

2017-01-01

This paper presents the design and development of a friction-based coupling device for a fiber-optic monitoring system capable of measuring pressure, strain, and temperature that can be deployed on existing subsea structures. A summary is provided of the design concept, prototype development, prototype performance testing, and subsequent design refinements of the device. The results of laboratory testing of the first prototype performed at the National Aeronautics and Space Administration (NASA) Johnson Space Center (JSC) are also included. Limitations of the initial concept were identified during testing and future design improvements were proposed and later implemented. These new features enhance the coupling of the sensor device and improve the monitoring system measurement capabilities. A major challenge of a post-installed instrumentation monitoring system is to ensure adequate coupling between the instruments and the structure of interest for reliable measurements. Friction-based devices have the potential to overcome coupling limitations caused by marine growth and soil contamination on flowlines, risers, and other subsea structures. The work described in this paper investigates the design and test of a friction-based coupling device (herein referred to as a friction clamp) which is suitable for pipelines and structures that are suspended in the water column as well as for those that are resting on the seabed. The monitoring elements consist of fiberoptic sensors that are bonded to a stainless steel clamshell assembly with a high-friction surface coating. The friction clamp incorporates a single hinge design to facilitate installation of the clamp and dual rows of opposing fasteners to distribute the clamping force along the structure. The friction clamp can be modified to be installed by commercial divers in shallow depths or by remotely operated vehicles in deep-water applications. NASA-JSC was involved in the selection and testing of the friction coating, and in the design and testing of the prototype clamp device. Four-inch diameter and eight-inch diameter sub-scale friction clamp prototypes were built and tested to evaluate the strain measuring capabilities of the design under different loading scenarios. The testing revealed some limitations of the initial design concept, and subsequent refinements were explored to improve the measurement performance of the system. This study was part of a collaboration between NASA-JSC and Astro Technology Inc. within a study called Clear Gulf. The primary objective of the Clear Gulf study is to develop advanced instrumentation technologies that will improve operational safety and reduce the risk of hydrocarbon spillage. NASA provided unique insights, expansive test facilities, and technical expertise to advance technologies that will benefit the environment, the public, and commercial industries.

Research on the tool holder mode in high speed machining

NASA Astrophysics Data System (ADS)

Zhenyu, Zhao; Yongquan, Zhou; Houming, Zhou; Xiaomei, Xu; Haibin, Xiao

2018-03-01

High speed machining technology can improve the processing efficiency and precision, but also reduce the processing cost. Therefore, the technology is widely regarded in the industry. With the extensive application of high-speed machining technology, high-speed tool system has higher and higher requirements on the tool chuck. At present, in high speed precision machining, several new kinds of clip heads are as long as there are heat shrinkage tool-holder, high-precision spring chuck, hydraulic tool-holder, and the three-rib deformation chuck. Among them, the heat shrinkage tool-holder has the advantages of high precision, high clamping force, high bending rigidity and dynamic balance, etc., which are widely used. Therefore, it is of great significance to research the new requirements of the machining tool system. In order to adapt to the requirement of high speed machining precision machining technology, this paper expounds the common tool holder technology of high precision machining, and proposes how to select correctly tool clamping system in practice. The characteristics and existing problems are analyzed in the tool clamping system.

Use of the Satinsky clamp for hilar clamping during robotic partial nephrectomy: indications, technique, and multi-center outcomes.

PubMed

Abdullah, Newaj; Rahbar, Haider; Barod, Ravi; Dalela, Deepansh; Larson, Jeff; Johnson, Michael; Mass, Alon; Zargar, Homayoun; Kaouk, Jihad; Allaf, Mohamad; Bhayani, Sam; Stifelman, Michael; Rogers, Craig

2017-03-01

A Satinsky clamp may be a backup option for hilar clamping during robotic partial nephrectomy (RPN) if there are challenges with application of bulldog clamps, but there are potential safety concerns. We evaluate outcomes of RPN using Satinsky vs. bulldog clamps, and provide tips for safe use of the Satinsky as a backup option. Using a multi-center database, we identified 1073 patients who underwent RPN between 2006 and 2013, and had information available about method of hilar clamping (bulldog clamp vs. Satinsky clamp). Patient baseline characteristics, tumor features, and perioperative outcomes were compared between the Satinsky and bulldog clamp groups. A Satinsky clamp was used for hilar clamping in 94 (8.8 %) RPN cases, and bulldog clamps were used in 979 (91.2 %) cases. The use of a Satinsky clamp was associated with greater operative time (198 vs. 175 min, p < 0.001), estimated blood loss (EBL, 200 vs. 100 ml, p < 0.001), warm ischemia time (WIT, 20 vs. 19 min, p = 0.036), transfusion rate (12.8 vs. 4.8 %, p = 0.001), and hospital stay (3 vs. 2 days, p < 0.001). Tumor characteristics and number of renal vessels were similar between groups. There were six intraoperative complications in the Satinsky clamp group, but none were directly related to the Satinsky clamp. On multivariable analysis, the use of the Satinsky clamp was not associated with increase in intraoperative or Clavien ≥3 postoperative complications, positive surgical margin rate or percentage change in estimated glomerular filtration rate. A Satinsky clamp can be a backup option for hilar clamping during challenging RPN cases, but requires careful technique, and was rarely necessary.

Effect of sterilization on stiffness and dimensional stability of rubber-dam clamps.

PubMed

Giebink, D L; Mathieu, G P; Hondrum, S O

1996-01-01

Simulated clinical conditions were used to test the effect of sterilization on rubber-dam clamp stiffness and dimension. Sixty Hygienic and Ivory W7 clamps were either steam or dry heat sterilized and compared to controls. Stiffness and dimensional change between Ivory clamp groups was significant (p<.0001); the sterilized clamps showed less change than the controls. Hygienic groups showed a significant different between the control and dry heat groups (p<.05); the sterilized clamps showed less change than the controls. The change in stiffness and interjaw width for all Ivory clamps compared to all Hygienic clamps was significant (p<.0001). The Hygienic clamps changes less than the Ivory clamps. The results indicate that steam and dry heat sterilization do not affect retention of rubber-dam clamps.

Noninvasive glucose sensing by transcutaneous Raman spectroscopy

NASA Astrophysics Data System (ADS)

Shih, Wei-Chuan; Bechtel, Kate L.; Rebec, Mihailo V.

2015-05-01

We present the development of a transcutaneous Raman spectroscopy system and analysis algorithm for noninvasive glucose sensing. The instrument and algorithm were tested in a preclinical study in which a dog model was used. To achieve a robust glucose test system, the blood levels were clamped for periods of up to 45 min. Glucose clamping and rise/fall patterns have been achieved by injecting glucose and insulin into the ear veins of the dog. Venous blood samples were drawn every 5 min and a plasma glucose concentration was obtained and used to maintain the clamps, to build the calibration model, and to evaluate the performance of the system. We evaluated the utility of the simultaneously acquired Raman spectra to be used to determine the plasma glucose values during the 8-h experiment. We obtained prediction errors in the range of ˜1.5-2 mM. These were in-line with a best-case theoretical estimate considering the limitations of the signal-to-noise ratio estimates. As expected, the transition regions of the clamp study produced larger predictive errors than the stable regions. This is related to the divergence of the interstitial fluid (ISF) and plasma glucose values during those periods. Two key contributors to error beside the ISF/plasma difference were photobleaching and detector drift. The study demonstrated the potential of Raman spectroscopy in noninvasive applications and provides areas where the technology can be improved in future studies.

Noninvasive glucose sensing by transcutaneous Raman spectroscopy.

PubMed

Shih, Wei-Chuan; Bechtel, Kate L; Rebec, Mihailo V

2015-05-01

We present the development of a transcutaneous Raman spectroscopy system and analysis algorithm for noninvasive glucose sensing. The instrument and algorithm were tested in a preclinical study in which a dog model was used. To achieve a robust glucose test system, the blood levels were clamped for periods of up to 45 min. Glucose clamping and rise/fall patterns have been achieved by injecting glucose and insulin into the ear veins of the dog. Venous blood samples were drawn every 5 min and a plasma glucose concentration was obtained and used to maintain the clamps, to build the calibration model, and to evaluate the performance of the system. We evaluated the utility of the simultaneously acquired Raman spectra to be used to determine the plasma glucose values during the 8-h experiment. We obtained prediction errors in the range of ~1.5-2  mM. These were in-line with a best-case theoretical estimate considering the limitations of the signal-to-noise ratio estimates. As expected, the transition regions of the clamp study produced larger predictive errors than the stable regions. This is related to the divergence of the interstitial fluid (ISF) and plasma glucose values during those periods. Two key contributors to error beside the ISF/plasma difference were photobleaching and detector drift. The study demonstrated the potential of Raman spectroscopy in noninvasive applications and provides areas where the technology can be improved in future studies.

Clamping characteristics study on different types of clamping unit

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

Jiao, Zhiwei; Liu, Haichao; Xie, Pengcheng

2015-05-22

Plastic products are becoming more and more widely used in aerospace, IT, digital electronics and many other fields. With the development of technology, the requirement of product precision is getting higher and higher. However, type and working performance of clamping unit play a decisive role in product precision. Clamping characteristics of different types of clamping unit are discussed in this article, which use finite element numerical analysis method through the software ABAQUS to study the clamping uniformity, and detect the clamping force repeatability precision. The result shows that compared with toggled three-platen clamping unit, clamping characteristics of internal circulation two-platenmore » clamping unit are better, for instance, its mold cavity deformation and force that bars and mold parting surface suffered are more uniform, and its clamping uniformity and repeatability precision is also better.« less

Evaluation of Grounding Impedance of a Complex Lightning Protective System Using Earth Ground Clamp Measurements and ATP Modeling

NASA Technical Reports Server (NTRS)

Mata, Carlos T.; Rakov, V. A.; Mata, Angel G.

2010-01-01

A new Lightning Protection System (LPS) was designed and built at Launch Complex 39B (LC39B), at the Kennedy Space Center (KSC), Florida, which consists of a catenary wire system (at a height of about 181 meters above ground level) supported by three insulators installed atop three towers in a triangular configuration. A total of nine downconductors (each about 250 meters long, on average) are connected to the catenary wire system. Each of the nine downconductors is connected to a 7.62-meter radius circular counterpoise conductor with six equally spaced 6-meter long vertical grounding rods. Grounding requirements at LC39B call for all underground and above ground metallic piping, enclosures, raceways, and cable trays, within 7.62 meters of the counterpoise, to be bounded to the counterpoise, which results in a complex interconnected grounding system, given the many metallic piping, raceways, and cable trays that run in multiple direction around LC39B. The complexity of this grounding system makes the fall of potential method, which uses multiple metallic rods or stakes, unsuitable for measuring the grounding impedances of the downconductors. To calculate the downconductors grounding impedance, an Earth Ground Clamp (a stakeless grounding resistance measuring device) and a LPS Alternative Transient Program (ATP) model are used. The Earth Ground Clamp is used to measure the loop impedance plus the grounding impedance of each downconductor and the ATP model is used to calculate the loop impedance of each downconductor circuit. The grounding impedance of the downconductors is then calculated by subtracting the ATP calculated loop impedances from the Earth Ground Clamp measurements.

Voltage-Clamp Studies on Uterine Smooth Muscle

PubMed Central

Anderson, Nels C.

1969-01-01

These studies have developed and tested an experimental approach to the study of membrane ionic conductance mechanisms in strips of uterine smooth muscle. The experimental and theoretical basis for applying the double sucrose-gap technique is described along with the limitations of this system. Nonpropagating membrane action potentials were produced in response to depolarizing current pulses under current-clamp conditions. The stepwise change of membrane potential under voltage-clamp conditions resulted in a family of ionic currents with voltage- and time-dependent characteristics. In sodium-free solution the peak transient current decreased and its equilibrium potential shifted along the voltage axis toward a more negative internal potential. These studies indicate a sodium-dependent, regenerative excitation mechanism. PMID:5796366

Baseline Design Compliance Matrix for the Rotary Mode Core Sampling System

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

LECHELT, J.A.

2000-10-17

The purpose of the design compliance matrix (DCM) is to provide a single-source document of all design requirements associated with the fifteen subsystems that make up the rotary mode core sampling (RMCS) system. It is intended to be the baseline requirement document for the RMCS system and to be used in governing all future design and design verification activities associated with it. This document is the DCM for the RMCS system used on Hanford single-shell radioactive waste storage tanks. This includes the Exhauster System, Rotary Mode Core Sample Trucks, Universal Sampling System, Diesel Generator System, Distribution Trailer, X-Ray Cart System,more » Breathing Air Compressor, Nitrogen Supply Trailer, Casks and Cask Truck, Service Trailer, Core Sampling Riser Equipment, Core Sampling Support Trucks, Foot Clamp, Ramps and Platforms and Purged Camera System. Excluded items are tools such as light plants and light stands. Other items such as the breather inlet filter are covered by a different design baseline. In this case, the inlet breather filter is covered by the Tank Farms Design Compliance Matrix.« less

Design and control of a novel gastroscope intervention mechanism with circumferentially pneumatic-driven clamping function.

PubMed

Li, Yanmin; Liu, Hao; Hao, Siwen; Li, Hongyi; Han, Jianda; Yang, Yunsheng

2017-03-01

Robot-assisted manipulation is promising for solving problems such as understaffing and the risk of infection in gastro-intestinal endoscopy. However, the commonly used friction rollers in few existing systems have a potential risk of deforming flexible endoscopes for non-uniform clamping. This paper presents a robotic system for a standard flexible endoscope and focuses on a novel gastroscope intervention mechanism (GIM), which provides circumferentially uniform clamping with an airbag. The GIM works with a relay-on mechanism in a way similar to manual operation. The shear stiffness of airbag and the critical slipping force (CSF) were analysed to determine the parameters of the airbag. A fuzzy PID controller was employed to realize a fast response and high accuracy of pneumatic actuation. Experiments were performed to evaluate the accuracy, stiffness and CSF. In vitro and in vivo animal experiments were also carried out. The GIM realized an accuracy of 0.025 ± 0.2 mm and -0.03 ± 0.25° for push-pull and rotation without delivery resistance. Under < 10 N delivery resistance, the error caused by the airbag stiffness was < 0.24 mm. A quadratic polynomial could be used to describe the relationship between the CSF and pneumatic pressure. The novel GIM could effectively deliver gastroscopes. The pneumatic-driven clamping method proposed could protect the gastroscope by circumferentially uniform clamping force and the CSF could be properly controlled to guarantee operating safety. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Reversible fastener clamp load monitor with continuous visual or remote readout

NASA Astrophysics Data System (ADS)

Hodge, Malcolm H.; Kausel, Theodore C., Jr.; Begley, Matthew R.

1998-03-01

SIMS has developed a simple means for detecting and monitoring both absolute and relative clamp load, or bolt tension, in fastener systems. More than twenty-five percent of automotive failures are known to be due to undetected loss of fastener clamp load. While the equivalent aerospace maintenance statistics are not known, the average automobile has 3,500 fasteners while a Boeing 747 has closer to one million. It is therefore anticipated that the new SensaBolt clamp load tracking system could find wide applications in the aerospace arena. We describe a visually-evident and retrofitted clamp load monitoring design which is based on the differential joint substrate compression at, and immediately adjacent to, the fastener location. This intrinsically-accurate indicator does not necessarily require alteration in either the bolt or nut geometries, thereby facilitating product introduction and retrofit in aging aircraft applications. In addition, SensaBolt's sole reliance on substrate compression renders it more accurate then torque wrench or turn-of-nut techniques. Readout may be accomplished by any of three principal methods: for those applications with ease of access to the sensor, loss of tension can be determined by direct visual inspection. Application of a standard wrench can then be made to restore the fastener's proper tightness, per the SensaBolt indicators. In those instances where line-of-sight is unimpeded and more formal inspection is desired, the SensaBolt may be interrogated by a laser scanner bar code reader. Finally, SensaBolt may be addressed by the SIMS fiber optic harness for those instances where full-time remote interrogation is desired.

Zero ischemia robotic-assisted partial nephrectomy in Alberta: Initial results of a novel approach.

PubMed

Forbes, Ellen; Cheung, Douglas; Kinnaird, Adam; Martin, Blair St

2015-01-01

Partial nephrectomy remains the standard of care in early stage, organ-confined renal tumours. Recent evidence suggests that minimally invasive surgery can proceed without segmental vessel clamping. In this study, we review our experience at a Canadian centre with zero ischemia robotic-assisted partial nephrectomy (RAPN). A retrospective chart review of zero ischemia RAPN was performed. All surgeries were consecutive partial nephrectomies performed by the same surgeon at a tertiary care centre in Northern Alberta. The mean follow-up period was 28 months. These outcomes were compared against the current standards for zero ischemia (as outlined by the University of Southern California Institute of Urology [USC]). We included 21 patients who underwent zero ischemia RAPN between January 2012 and June 2013. Baseline data were similar to contemporary studies. Twelve (57.1%) required no vascular clamping, 7 (33.3%) required clamping of a single segmental artery, and 2 (9.5%) required clamping of two segmental arteries. We achieved an average estimated blood loss of 158 cc, with a 9.2% average increase in creatinine postoperatively. Operating time and duration of hospital stay were short at 153 minutes and 2.2 days, respectively. Zero ischemia partial nephrectomy was a viable option at our institution with favourable results in terms of intra-operative blood loss and postoperative creatinine change compared to results from contemporary standard zero ischemia studies (USC). To our knowledge, this is the first study to review an initial experience with the zero ischemia protocol in robotic-assisted partial nephrectomies at a Canadian hospital.

Magnetic resonance imaging for cerebral lesions during minimal invasive mitral valve surgery: study protocol for a randomized controlled trial.

PubMed

Barbero, Cristina; Ricci, Davide; Cura Stura, Erik; Pellegrini, Augusto; Marchetto, Giovanni; ElQarra, Suad; Boffini, Massimo; Passera, Roberto; Valentini, Maria Consuelo; Rinaldi, Mauro

2017-02-21

Recent data have highlighted a higher rate of neurological injuries in minimal invasive mitral valve surgery (MIMVS) compared with the standard sternotomy approach; therefore, the role of specific clamping techniques and perfusion strategies on the occurrence of this complication is a matter of discussion in the medical literature. The purpose of this trial is to prospectively evaluate major, minor and silent neurological events in patients undergoing right mini-thoracotomy mitral valve surgery using retrograde perfusion and an endoaortic clamp or a transthoracic clamp. A prospective, blinded, randomized controlled study on the rate of neurological embolizations during MIMVS started at the University of Turin in June 2014. Major, minor and silent neurological events are being investigated through standard neurological evaluation and magnetic resonance imaging assessment. The magnetic resonance imaging protocol includes conventional sequences for the morphological and quantitative assessment and nonconventional sequences for the white matter microstructural evaluation. Imaging studies are performed before surgery as baseline assessment and on the third postoperative day and, in patients who develop postoperative ischemic lesions, after 6 months. Despite recent concerns raised about the endoaortic setting with retrograde perfusion, we expect to show equivalence in terms of neurological events of this technique compared with the transthoracic clamp in a selected cohort of patients. With the first results expected in December 2016 the findings would be of help in confirming the efficacy and safety of MIMVS. ClinicalTrials.gov, Identifier: NCT02818166 . Registered on 8 February 2016 - trial retrospectively registered.

Noninvasive Intracranial Pressure Monitoring Using Advanced Machine Learning Techniques

DTIC Science & Technology

2013-11-01

drainage requiring removal to prevent infection or to allow computed tomography scan. 3. If clinicians had the ability to predict near-future ICP... drainage of cerebrospinal fluid from the ventricles; however, ICP readings are only accurate when the external drainage system is clamped. ICP clamping... craniotomy for hemorrhage evacuation or a craniectomy for treatment of cerebral edema. Overall in-hospital mortality was 19.4%. Eight hundred and ninety

46 CFR 27.211 - What are the specifications for fuel systems on towing vessels whose construction was contracted...

Code of Federal Regulations, 2013 CFR

2013-10-01

...; and (2) Nonmetallic flexible hose is acceptable if it— (i) Is used in lengths of not more than 0.76... reinforced with wire braid; and (v) Either,— (A) If it is designed for use with compression fittings, is... clamps at each end of the hose. Clamps must not rely on spring tension and must be installed beyond the...

46 CFR 27.211 - What are the specifications for fuel systems on towing vessels whose construction was contracted...

Code of Federal Regulations, 2012 CFR

2012-10-01

...; and (2) Nonmetallic flexible hose is acceptable if it— (i) Is used in lengths of not more than 0.76... reinforced with wire braid; and (v) Either,— (A) If it is designed for use with compression fittings, is... clamps at each end of the hose. Clamps must not rely on spring tension and must be installed beyond the...

46 CFR 27.211 - What are the specifications for fuel systems on towing vessels whose construction was contracted...

Code of Federal Regulations, 2011 CFR

2011-10-01

...; and (2) Nonmetallic flexible hose is acceptable if it— (i) Is used in lengths of not more than 0.76... reinforced with wire braid; and (v) Either,— (A) If it is designed for use with compression fittings, is... clamps at each end of the hose. Clamps must not rely on spring tension and must be installed beyond the...

46 CFR 27.211 - What are the specifications for fuel systems on towing vessels whose construction was contracted...

Code of Federal Regulations, 2014 CFR

2014-10-01

...; and (2) Nonmetallic flexible hose is acceptable if it— (i) Is used in lengths of not more than 0.76... reinforced with wire braid; and (v) Either,— (A) If it is designed for use with compression fittings, is... clamps at each end of the hose. Clamps must not rely on spring tension and must be installed beyond the...

Ion channel pharmacology under flow: automation via well-plate microfluidics.

PubMed

Spencer, C Ian; Li, Nianzhen; Chen, Qin; Johnson, Juliette; Nevill, Tanner; Kammonen, Juha; Ionescu-Zanetti, Cristian

2012-08-01

Automated patch clamping addresses the need for high-throughput screening of chemical entities that alter ion channel function. As a result, there is considerable utility in the pharmaceutical screening arena for novel platforms that can produce relevant data both rapidly and consistently. Here we present results that were obtained with an innovative microfluidic automated patch clamp system utilizing a well-plate that eliminates the necessity of internal robotic liquid handling. Continuous recording from cell ensembles, rapid solution switching, and a bench-top footprint enable a number of assay formats previously inaccessible to automated systems. An electro-pneumatic interface was employed to drive the laminar flow of solutions in a microfluidic network that delivered cells in suspension to ensemble recording sites. Whole-cell voltage clamp was applied to linear arrays of 20 cells in parallel utilizing a 64-channel voltage clamp amplifier. A number of unique assays requiring sequential compound applications separated by a second or less, such as rapid determination of the agonist EC(50) for a ligand-gated ion channel or the kinetics of desensitization recovery, are enabled by the system. In addition, the system was validated via electrophysiological characterizations of both voltage-gated and ligand-gated ion channel targets: hK(V)2.1 and human Ether-à-go-go-related gene potassium channels, hNa(V)1.7 and 1.8 sodium channels, and (α1) hGABA(A) and (α1) human nicotinic acetylcholine receptor receptors. Our results show that the voltage dependence, kinetics, and interactions of these channels with pharmacological agents were matched to reference data. The results from these IonFlux™ experiments demonstrate that the system provides high-throughput automated electrophysiology with enhanced reliability and consistency, in a user-friendly format.

An optogenetics- and imaging-assisted simultaneous multiple patch-clamp recording system for decoding complex neural circuits

PubMed Central

Wang, Guangfu; Wyskiel, Daniel R; Yang, Weiguo; Wang, Yiqing; Milbern, Lana C; Lalanne, Txomin; Jiang, Xiaolong; Shen, Ying; Sun, Qian-Quan; Zhu, J Julius

2015-01-01

Deciphering neuronal circuitry is central to understanding brain function and dysfunction, yet it remains a daunting task. To facilitate the dissection of neuronal circuits, a process requiring functional analysis of synaptic connections and morphological identification of interconnected neurons, we present here a method for stable simultaneous octuple patch-clamp recordings. This method allows physiological analysis of synaptic interconnections among 4–8 simultaneously recorded neurons and/or 10–30 sequentially recorded neurons, and it allows anatomical identification of >85% of recorded interneurons and >99% of recorded principal neurons. We describe how to apply the method to rodent tissue slices; however, it can be used on other model organisms. We also describe the latest refinements and optimizations of mechanics, electronics, optics and software programs that are central to the realization of a combined single- and two-photon microscopy–based, optogenetics- and imaging-assisted, stable, simultaneous quadruple–viguple patch-clamp recording system. Setting up the system, from the beginning of instrument assembly and software installation to full operation, can be completed in 3–4 d. PMID:25654757

The Mechanism of Extracellular Stimulation of Nerve Cells on an Electrolyte-Oxide-Semiconductor Capacitor

PubMed Central

Schoen, Ingmar; Fromherz, Peter

2007-01-01

Extracellular excitation of neurons is applied in studies of cultured networks and brain tissue, as well as in neuroprosthetics. We elucidate its mechanism in an electrophysiological approach by comparing voltage-clamp and current-clamp recordings of individual neurons on an insulated planar electrode. Noninvasive stimulation of neurons from pedal ganglia of Lymnaea stagnalis is achieved by defined voltage ramps applied to an electrolyte/HfO2/silicon capacitor. Effects on the smaller attached cell membrane and the larger free membrane are distinguished in a two-domain-stimulation model. Under current-clamp, we study the polarization that is induced for closed ion channels. Under voltage-clamp, we determine the capacitive gating of ion channels in the attached membrane by falling voltage ramps and for comparison also the gating of all channels by conventional variation of the intracellular voltage. Neuronal excitation is elicited under current-clamp by two mechanisms: Rising voltage ramps depolarize the free membrane such that an action potential is triggered. Falling voltage ramps depolarize the attached membrane such that local ion currents are activated that depolarize the free membrane and trigger an action potential. The electrophysiological analysis of extracellular stimulation in the simple model system is a basis for its systematic optimization in neuronal networks and brain tissue. PMID:17098803

Erratum to "On guided wave propagation in fully clamped porous functionally graded nanoplates" [Acta Astronaut. 143 (2018) 380-390

NASA Astrophysics Data System (ADS)

Karami, Behrouz; Janghorban, Maziar; Li, Li

2018-03-01

We found a proofing error existing in the affiliation of the first and second authors of our article [1], We found a proofing error existing in the affiliation of the first and second authors of our article [1]. The correct affiliation should be "Department of Mechanical Engineering, Marvdasht Branch, Islamic Azad University, Marvdasht, Iran".

Impact of Renal Hilar Control on Outcomes of Robotic Partial Nephrectomy: Systematic Review and Cumulative Meta-analysis.

PubMed

Cacciamani, Giovanni E; Medina, Luis G; Gill, Tania S; Mendelsohn, Alec; Husain, Fatima; Bhardwaj, Lokesh; Artibani, Walter; Sotelo, Renè; Gill, Inderbir S

2018-02-05

During robotic partial nephrectomy (RPN), various techniques of hilar control have been described, including on-clamp, early unclamping, selective/super-selective clamping, and completely-unclamped RPN. To evaluate the impact of various hilar control techniques on perioperative, functional, and oncological outcomes of RPN for tumors. We conducted a systematic literature review and meta-analysis of all comparative studies on various hilar control techniques during RPN using PubMed, Scopus, and Web of Science according to the Preferred Reporting Items for Systematic Review and Meta-analysis statement, and Methods and Guide for Effectiveness and Comparative Effectiveness Review of the Agency for Healthcare Research and Quality. Cumulative meta-analysis of comparative studies was conducted using Review Manager 5.3. Of 987 RPN publications in the literature, 19 qualified for this analysis. Comparison of off-clamp versus on-clamp RPN (n=9), selective clamping versus on-clamp RPN (n=3), super selective clamping versus on-clamp RPN (n=5), and early unclamped versus on-clamp (n=3) were reported. Patients undergoing RPN using off-clamp, selective/super selective, or early unclamp techniques had higher estimated blood loss compared with on-clamp RPN (weight mean difference [WMD]: 47.83, p=0.000, WMD: 41.06, p=0.02, and WMD: 37.50, p=0.47); however, this did not seem clinically relevant, since transfusion rates were similar (odds ratio [OR]: 0.98, p=0.95, OR: 0.72, p=0.7, and OR: 1.36, p=0.33, respectively). All groups appeared similar with regards to hospital stay, transfusions, overall and major complications, and positive cancer margin rates. Short- and long-term renal functional outcomes appeared superior in the off-clamp and super selective clamp groups compared with the on-clamp RPN cohort. Off-clamp, selective/super selective clamp, and early unclamp hilar control techniques are safe and feasible approaches for RPN surgery, with similar perioperative and oncological outcomes compared with on-clamp RPN. Minimizing global renal ischemia may provide superior renal function preservation. However, higher quality data are necessary for definitive conclusions in this regard. The objective of partial nephrectomy is to treat the cancer while maximizing renal function preservation. Clamping the main vessels is done primarily to reduce the blood loss during partial nephrectomy; however, vascular clamping can compromise kidney function. In order to avoid clamping, various techniques have been described. Our analysis showed that techniques that avoid main renal artery clamping during RPN are associated with better renal function preservation, yet deliver non-inferior perioperative and oncological outcomes as compared with robotic partial nephrectomy procedures that clamp the main vessels. Copyright © 2018 European Association of Urology. Published by Elsevier B.V. All rights reserved.

Clamp usable as jig and lifting clamp

DOEpatents

Tsuyama, Yoshizo

1976-01-01

There is provided a clamp which is well suited for use as a lifting clamp for lifting and moving materials of assembly in a shipyard, etc. and as a pulling jig in welding and other operations. The clamp comprises a clamp body including a shackle for engagement with a pulling device and a slot for receiving an article, and a pair of jaws provided on the leg portions of the clamp body on the opposite sides of the slot to grip the article in the slot, one of said jaws consisting of a screw rod and the other jaw consisting of a swivel jaw with a spherical surface, whereby when the article clamped in the slot by the pair of jaws tends to slide in any direction with respect to the clamp body, the article is more positively gripped by the pair of jaws.

High-speed pressure clamp.

PubMed

Besch, Stephen R; Suchyna, Thomas; Sachs, Frederick

2002-10-01

We built a high-speed, pneumatic pressure clamp to stimulate patch-clamped membranes mechanically. The key control element is a newly designed differential valve that uses a single, nickel-plated piezoelectric bending element to control both pressure and vacuum. To minimize response time, the valve body was designed with minimum dead volume. The result is improved response time and stability with a threefold decrease in actuation latency. Tight valve clearances minimize the steady-state air flow, permitting us to use small resonant-piston pumps to supply pressure and vacuum. To protect the valve from water contamination in the event of a broken pipette, an optical sensor detects water entering the valve and increases pressure rapidly to clear the system. The open-loop time constant for pressure is 2.5 ms for a 100-mmHg step, and the closed-loop settling time is 500-600 micros. Valve actuation latency is 120 micros. The system performance is illustrated for mechanically induced changes in patch capacitance.

Cable clamp bolt fixture facilitates assembly in close quarters

NASA Technical Reports Server (NTRS)

Sunderland, G. H.

1967-01-01

Cable clamp bolt holding fixture facilitates forming of electrical cable runs in limited equipment space. The fixture engages the threads of the short clamp bolt through the clamp and maintains tension against clamp tendency to open while the operator installs the nut without difficulty.

Downhole hydraulic seismic generator

DOEpatents

Gregory, Danny L.; Hardee, Harry C.; Smallwood, David O.

1992-01-01

A downhole hydraulic seismic generator system for transmitting energy wave vibrations into earth strata surrounding a borehole. The system contains an elongated, unitary housing operably connected to a well head aboveground by support and electrical cabling, and contains clamping apparatus for selectively clamping the housing to the walls of the borehole. The system further comprises a hydraulic oscillator containing a double-actuating piston whose movement is controlled by an electro-servovalve regulating a high pressure hydraulic fluid flow into and out of upper and lower chambers surrounding the piston. The spent hydraulic fluid from the hydraulic oscillator is stored and pumped back into the system to provide high pressure fluid for conducting another run at the same, or a different location within the borehole.

Split-tapered joint clamping device

DOEpatents

Olsen, Max J.; Schwartz, Jr., John F.

1988-01-01

This invention relates to a clamping device for removably attaching a tool element to a bracket element wherein a bracket element is disposed in a groove in the tool and a clamping member is disposed in said groove and in engagement with a clamping face of the bracket and a wall of the groove and with the clamping member having pivot means engaging the bracket and about which the clamping member rotates.

Effect of complete hilar versus only renal artery clamping on renal histomorphology following ischemia/reperfusion injury in an experimental model.

PubMed

Umul, M; Cal, A C; Turna, B; Oktem, G; Aydın, H H

2016-01-01

To evaluate the effect of temporary complete hilar versus only renal artery clamping with different duration of warm ischemia on renal functions, and possibly identify a "safe" clamping type and duration of renal ischemia. Fifty male rabbits have been incorporated to study. Rabbits were subjected to ischemia/reperfusion injury by temporary vascular clamping. Reagents were randomized to 3 experimental groups (only renal artery clamping, complete hilar clamping, sham surgery) and sub-groups were determined according to different clamping times (30 and 60 minutes). Median laparotomy and left renal hilus dissection were performed to sham group. Only artery or complete hilar clamping was performed for 30 or 60 minutes by microvascular bulldog clamps to other reagents. Rabbits were sacrificed 10 days after primary surgery and left nephrectomy performed. Nephrectomy materials were evaluated for the level of nitric-oxide synthase (NOS) immunoreactivity, malondialdehyde (MDA) level and superoxide dismutase (SOD) activity and an electron microscopic examination was performed. NOS immunoreactivity was correlated with the temporary clamping time. We also observed that complete hilar vascular clamping entails an increase on NOS immunoreactivity. MDA levels were similar for all experimental surgery groups (p = 0.42). The SOD activity was decreased among all subgroups compared with sham surgery. But the significant decrease occurred in 30 minutes only artery and 30 minutes complete hilar clamping groups in proportion to sham surgery (p = 0.026 and p = 0.019, respectively). This current study suggested that only renal artery clamping under 30 minutes is more appropriate during renal surgical procedures requiring temporary vascular clamping.

A nonlinear electrostatic potential change in the T-system of skeletal muscle detected under passive recording conditions using potentiometric dyes

PubMed Central

1990-01-01

Voltage-sensing dyes were used to examine the electrical behavior of the T-system under passive recording conditions similar to those commonly used to detect charge movement. These conditions are designed to eliminate all ionic currents and render the T-system potential linear with respect to the command potential applied at the surface membrane. However, we found an unexpected nonlinearity in the relationship between the dye signal from the T-system and the applied clamp potential. An additional voltage- and time-dependent optical signal appears over the same depolarizing range of potentials where change movement and mechanical activation occur. This nonlinearity is not associated with unblocked ionic currents and cannot be attributed to lack of voltage clamp control of the T-system, which appears to be good under these conditions. We propose that a local electrostatic potential change occurs in the T-system upon depolarization. An electrostatic potential would not be expected to extend beyond molecular distances of the membrane and therefore would be sensed by a charged dye in the membrane but not by the voltage clamp, which responds solely to the potential of the bulk solution. Results obtained with different dyes suggest that the location of the phenomena giving rise to the extra absorbance change is either intramembrane or at the inner surface of the T-system membrane. PMID:2299329

Behavior of fiber reinforced metal laminates at high strain rate

NASA Astrophysics Data System (ADS)

Newaz, Golam; Sasso, Marco; Amodio, Dario; Mancini, Edoardo

2018-05-01

Carbon Fiber Reinforced Aluminum Laminate (CARALL) is a good system for energy absorption through plastic deformation in aluminum and micro-cracking in the composite layers. Moreover, CARALL FMLs also provide excellent impact resistance due to the presence of aluminum layer. The focus of this research is to characterize the CARALL behavior under dynamic conditions. High strain rate tests on sheet laminate samples have been carried out by means of direct Split Hopkinson Tension Bar. The sample geometry and the clamping system were optimized by FEM simulations. The clamping system has been designed and optimized in order reduce impedance disturbance due to the fasteners and to avoid the excessive plastic strain outside the gauge region of the samples.

QPatch: the missing link between HTS and ion channel drug discovery.

PubMed

Mathes, Chris; Friis, Søren; Finley, Michael; Liu, Yi

2009-01-01

The conventional patch clamp has long been considered the best approach for studying ion channel function and pharmacology. However, its low throughput has been a major hurdle to overcome for ion channel drug discovery. The recent emergence of higher throughput, automated patch clamp technology begins to break this bottleneck by providing medicinal chemists with high-quality, information-rich data in a more timely fashion. As such, these technologies have the potential to bridge a critical missing link between high-throughput primary screening and meaningful ion channel drug discovery programs. One of these technologies, the QPatch automated patch clamp system developed by Sophion Bioscience, records whole-cell ion channel currents from 16 or 48 individual cells in a parallel fashion. Here, we review the general applicability of the QPatch to studying a wide variety of ion channel types (voltage-/ligand-gated cationic/anionic channels) in various expression systems. The success rate of gigaseals, formation of the whole-cell configuration and usable cells ranged from 40-80%, depending on a number of factors including the cell line used, ion channel expressed, assay development or optimization time and expression level in these studies. We present detailed analyses of the QPatch features and results in case studies in which secondary screening assays were successfully developed for a voltage-gated calcium channel and a ligand-gated TRP channel. The increase in throughput compared to conventional patch clamp with the same cells was approximately 10-fold. We conclude that the QPatch, combining high data quality and speed with user friendliness and suitability for a wide array of ion channels, resides on the cutting edge of automated patch clamp technology and plays a pivotal role in expediting ion channel drug discovery.

Natural frequency and stability analysis of a pipe conveying fluid with axially moving supports immersed in fluid

NASA Astrophysics Data System (ADS)

Ni, Qiao; Luo, Yangyang; Li, Mingwu; Yan, Hao

2017-09-01

Structural model for a slender and uniform pipe conveying fluid, with axially moving supports on both ends, immersed in an incompressible fluid, is formulated. Free vibration and stability of the system are studied through numerical calculation. First, the equations of motion of the system are derived in an absolute coordinate system. An "axial added mass coefficient" is adopted to amend the forces caused by the external fluid. Boundary conditions are fixed by using coordinated conversion. Then, numerical results of the natural frequency are obtained via the Galerkin method, both for pinned-pinned and clamped-clamped supports. The critical speeds of supports and several instability types are discussed. Last, the effects of the system parameters on the dynamics and instability of the system are investigated.

Lifting clamp positively grips structural shapes

NASA Technical Reports Server (NTRS)

Reinhardt, E. C.

1966-01-01

Welded steel clamps securely grip structural shapes of various sizes for crane operations. The clamp has adjustable clamping jaws and screw-operated internal v-jaws and provides greater safety than hoisting slings presently used. The structural member can be rotated in any manner, angle, or direction without being released by the clamp.

The effect of aliskiren on urinary cytokine/chemokine responses to clamped hyperglycaemia in type 1 diabetes.

PubMed

Cherney, David Z I; Reich, Heather N; Scholey, James W; Daneman, Denis; Mahmud, Farid H; Har, Ronnie L H; Sochett, Etienne B

2013-10-01

Acute clamped hyperglycaemia activates the renin-angiotensin-aldosterone system (RAAS) and increases the urinary excretion of inflammatory cytokines/chemokines in patients with uncomplicated type 1 diabetes mellitus. Our objective was to determine whether blockade of the RAAS would blunt the effect of acute hyperglycaemia on urinary cytokine/chemokine excretion, thereby giving insights into potentially protective effects of these agents prior to the onset of clinical nephropathy. Blood pressure, renal haemodynamic function (inulin and para-aminohippurate clearances) and urinary cytokines/chemokines were measured after 6 h of clamped euglycaemia (4-6 mmol/l) and hyperglycaemia (9-11 mmol/l) on two consecutive days in patients with type 1 diabetes mellitus (n = 27) without overt nephropathy. Measurements were repeated after treatment with aliskiren (300 mg daily) for 30 days. Before aliskiren, clamped hyperglycaemia increased filtration fraction (from 0.188 ± 0.007 to 0.206 ± 0.007, p = 0.003) and urinary fibroblast growth factor-2 (FGF2), IFN-α2 and macrophage-derived chemokine (MDC) (p < 0.005). After aliskiren, the filtration fraction response to hyperglycaemia was abolished, resulting in a lower filtration fraction after aliskiren under clamped hyperglycaemic conditions (p = 0.004), and none of the biomarkers increased in response to hyperglycaemia. Aliskiren therapy also reduced levels of urinary eotaxin, FGF2, IFN-α2, IL-2 and MDC during clamped hyperglycaemia (p < 0.005). The increased urinary excretion of inflammatory cytokines/chemokines in response to acute hyperglycaemia is blunted by RAAS blockade in humans with uncomplicated type 1 diabetes mellitus.

Universal power transistor base drive control unit

DOEpatents

Gale, Allan R.; Gritter, David J.

1988-01-01

A saturation condition regulator system for a power transistor which achieves the regulation objectives of a Baker clamp but without dumping excess base drive current into the transistor output circuit. The base drive current of the transistor is sensed and used through an active feedback circuit to produce an error signal which modulates the base drive current through a linearly operating FET. The collector base voltage of the power transistor is independently monitored to develop a second error signal which is also used to regulate base drive current. The current-sensitive circuit operates as a limiter. In addition, a fail-safe timing circuit is disclosed which automatically resets to a turn OFF condition in the event the transistor does not turn ON within a predetermined time after the input signal transition.

Universal power transistor base drive control unit

DOEpatents

Gale, A.R.; Gritter, D.J.

1988-06-07

A saturation condition regulator system for a power transistor is disclosed which achieves the regulation objectives of a Baker clamp but without dumping excess base drive current into the transistor output circuit. The base drive current of the transistor is sensed and used through an active feedback circuit to produce an error signal which modulates the base drive current through a linearly operating FET. The collector base voltage of the power transistor is independently monitored to develop a second error signal which is also used to regulate base drive current. The current-sensitive circuit operates as a limiter. In addition, a fail-safe timing circuit is disclosed which automatically resets to a turn OFF condition in the event the transistor does not turn ON within a predetermined time after the input signal transition. 2 figs.

Selective Arterial Clamping Versus Hilar Clamping for Minimally Invasive Partial Nephrectomy.

PubMed

Yezdani, Mona; Yu, Sue-Jean; Lee, David I

2016-05-01

Partial nephrectomy has become an accepted treatment of cT1 renal masses as it provides improved long-term renal function compared to radical nephrectomy (Campbell et al. J Urol. 182:1271-9, 2009). Hilar clamping is utilized to help reduce bleeding and improve visibility during tumor resection. However, concern over risk of kidney injury with hilar clamping has led to new techniques to reduce length of warm ischemia time (WIT) during partial nephrectomy. These techniques have progressed over the years starting with early hilar unclamping, controlled hypotension during tumor resection, selective arterial clamping, minimal margin techniques, and off-clamp procedures. Selective arterial clamping has progressed significantly over the years. The main question is what are the exact short- and long-term renal effects from increasing clamp time. Moreover, does it make sense to perform these more time-consuming or more complex procedures if there is no long-term preservation of kidney function? More recent studies have shown no difference in renal function 6 months from surgery when selective arterial clamping or even hilar clamping is employed, although there is short-term improved decline in estimated glomerular filtration rate (eGFR) with selective clamping and off-clamp techniques (Komninos et al. BJU Int. 115:921-8, 2015; Shah et al. 117:293-9, 2015; Kallingal et al. BJU Int. doi: 10.1111/bju.13192, 2015). This paper reviews the progression of total hilar clamping to selective arterial clamping (SAC) and the possible difference its use makes on long-term renal function. SAC may be attempted based on surgeon's decision-making, but may be best used for more complex, larger, more central or hilar tumors and in patients who have renal insufficiency at baseline or a solitary kidney.

Whole-Cell Electrical Activity Under Direct Mechanical Stimulus by AFM Cantilever Using Planar Patch Clamp Chip Approach

PubMed Central

Upadhye, Kalpesh V.; Candiello, Joseph E.; Davidson, Lance A.; Lin, Hai

2011-01-01

Patch clamp is a powerful tool for studying the properties of ion-channels and cellular membrane. In recent years, planar patch clamp chips have been fabricated from various materials including glass, quartz, silicon, silicon nitride, polydimethyl-siloxane (PDMS), and silicon dioxide. Planar patch clamps have made automation of patch clamp recordings possible. However, most planar patch clamp chips have limitations when used in combination with other techniques. Furthermore, the fabrication methods used are often expensive and require specialized equipments. An improved design as well as fabrication and characterization of a silicon-based planar patch clamp chip are described in this report. Fabrication involves true batch fabrication processes that can be performed in most common microfabrication facilities using well established MEMS techniques. Our planar patch clamp chips can form giga-ohm seals with the cell plasma membrane with success rate comparable to existing patch clamp techniques. The chip permits whole-cell voltage clamp recordings on variety of cell types including Chinese Hamster Ovary (CHO) cells and pheochromocytoma (PC12) cells, for times longer than most available patch clamp chips. When combined with a custom microfluidics chamber, we demonstrate that it is possible to perfuse the extra-cellular as well as intra-cellular buffers. The chamber design allows integration of planar patch clamp with atomic force microscope (AFM). Using our planar patch clamp chip and microfluidics chamber, we have recorded whole-cell mechanosensitive (MS) currents produced by directly stimulating human keratinocyte (HaCaT) cells using an AFM cantilever. Our results reveal the spatial distribution of MS ion channels and temporal details of the responses from MS channels. The results show that planar patch clamp chips have great potential for multi-parametric high throughput studies of ion channel proteins. PMID:22174731

The computational structural mechanics testbed architecture. Volume 2: The interface

NASA Technical Reports Server (NTRS)

Felippa, Carlos A.

1988-01-01

This is the third set of five volumes which describe the software architecture for the Computational Structural Mechanics Testbed. Derived from NICE, an integrated software system developed at Lockheed Palo Alto Research Laboratory, the architecture is composed of the command language CLAMP, the command language interpreter CLIP, and the data manager GAL. Volumes 1, 2, and 3 (NASA CR's 178384, 178385, and 178386, respectively) describe CLAMP and CLIP and the CLIP-processor interface. Volumes 4 and 5 (NASA CR's 178387 and 178388, respectively) describe GAL and its low-level I/O. CLAMP, an acronym for Command Language for Applied Mechanics Processors, is designed to control the flow of execution of processors written for NICE. Volume 3 describes the CLIP-Processor interface and related topics. It is intended only for processor developers.

The computational structural mechanics testbed architecture. Volume 2: Directives

NASA Technical Reports Server (NTRS)

Felippa, Carlos A.

1989-01-01

This is the second of a set of five volumes which describe the software architecture for the Computational Structural Mechanics Testbed. Derived from NICE, an integrated software system developed at Lockheed Palo Alto Research Laboratory, the architecture is composed of the command language (CLAMP), the command language interpreter (CLIP), and the data manager (GAL). Volumes 1, 2, and 3 (NASA CR's 178384, 178385, and 178386, respectively) describe CLAMP and CLIP and the CLIP-processor interface. Volumes 4 and 5 (NASA CR's 178387 and 178388, respectively) describe GAL and its low-level I/O. CLAMP, an acronym for Command Language for Applied Mechanics Processors, is designed to control the flow of execution of processors written for NICE. Volume 2 describes the CLIP directives in detail. It is intended for intermediate and advanced users.

Measuring beta-cell function relative to insulin sensitivity in youth: Does the hyperglycemic clamp suffice?

USDA-ARS?s Scientific Manuscript database

To compare beta-cell function relative to insulin sensitivity, disposition index (DI), calculated from two clamps (2cDI, insulin sensitivity from the hyperinsulinemic-euglycemic clamp and first-phase insulin from the hyperglycemic clamp) with the DI calculated from the hyperglycemic clamp alone (hcD...

21 CFR 882.4460 - Neurosurgical head holder (skull clamp).

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Neurosurgical head holder (skull clamp). 882.4460... holder (skull clamp). (a) Identification. A neurosurgical head holder (skull clamp) is a device used to clamp the patient's skull to hold head and neck in a particular position during surgical procedures. (b...

FPGA in-the-loop simulations of cardiac excitation model under voltage clamp conditions

NASA Astrophysics Data System (ADS)

Othman, Norliza; Adon, Nur Atiqah; Mahmud, Farhanahani

2017-01-01

Voltage clamp technique allows the detection of single channel currents in biological membranes in identifying variety of electrophysiological problems in the cellular level. In this paper, a simulation study of the voltage clamp technique has been presented to analyse current-voltage (I-V) characteristics of ion currents based on Luo-Rudy Phase-I (LR-I) cardiac model by using a Field Programmable Gate Array (FPGA). Nowadays, cardiac models are becoming increasingly complex which can cause a vast amount of time to run the simulation. Thus, a real-time hardware implementation using FPGA could be one of the best solutions for high-performance real-time systems as it provides high configurability and performance, and able to executes in parallel mode operation. For shorter time development while retaining high confidence results, FPGA-based rapid prototyping through HDL Coder from MATLAB software has been used to construct the algorithm for the simulation system. Basically, the HDL Coder is capable to convert the designed MATLAB Simulink blocks into hardware description language (HDL) for the FPGA implementation. As a result, the voltage-clamp fixed-point design of LR-I model has been successfully conducted in MATLAB Simulink and the simulation of the I-V characteristics of the ionic currents has been verified on Xilinx FPGA Virtex-6 XC6VLX240T development board through an FPGA-in-the-loop (FIL) simulation.

Temperature-Controlled Clamping and Releasing Mechanism

NASA Technical Reports Server (NTRS)

Rosing, David; Ford, Virginia

2005-01-01

A report describes the development of a mechanism that automatically clamps upon warming and releases upon cooling between temperature limits of approx. =180 K and approx. =293 K. The mechanism satisfied a need specific to a program that involved repeated excursions of a spectrometer between a room-temperature atmospheric environment and a cryogenic vacuum testing environment. The mechanism was also to be utilized in the intended application of the spectrometer, in which the spectrometer would be clamped for protection during launch of a spacecraft and released in the cold of outer space to allow it to assume its nominal configuration for scientific observations. The mechanism is passive in the sense that its operation does not depend on a control system and does not require any power other than that incidental to heating and cooling. The clamping and releasing action is effected by bolt-preloaded stacks of shape-memory-alloy (SMA) cylinders. In designing this mechanism, as in designing other, similar SMA mechanisms, it was necessary to account for the complex interplay among thermal expansion, elastic and inelastic deformation under load, and SMA thermomechanical properties.

External mean flow influence on sound transmission through finite clamped double-wall sandwich panels

NASA Astrophysics Data System (ADS)

Liu, Yu; Catalan, Jean-Cédric

2017-09-01

This paper studies the influence of an external mean flow on the sound transmission through finite clamped double-wall sandwich panels lined with poroelastic materials. Biot's theory is employed to describe wave propagation in poroelastic materials and various configurations of coupling the poroelastic layer to the facing plates are considered. The clamped boundary of finite panels are dealt with by the modal superposition theory and the weighted residual (Garlekin) method, leading to a matrix equation solution for the sound transmission loss (STL) through the structure. The theoretical model is validated against existing theories of infinite sandwich panels with and without an external flow. The numerical results of a single incident wave show that the external mean flow has significant effects on the STL which are coupled with the clamped boundary effect dominating in the low-frequency range. The external mean flow also influences considerably the limiting incidence angle of the panel system and the effect of the incidence angle on the STL. However, the influences of the azimuthal angle and the external flow orientation are negligible.

Robotic multi-well planar patch-clamp for native and primary mammalian cells

PubMed Central

Milligan, Carol J; Li, Jing; Sukumar, Piruthivi; Majeed, Yasser; Dallas, Mark L; English, Anne; Emery, Paul; Porter, Karen E; Smith, Andrew M; McFadzean, Ian; Beccano-Kelly, Dayne; Bahnasi, Yahya; Cheong, Alex; Naylor, Jacqueline; Zeng, Fanning; Liu, Xing; Gamper, Nikita; Jiang, Lin-Hua; Pearson, Hugh A; Peers, Chris; Robertson, Brian; Beech, David J

2009-01-01

Multi-well robotic planar patch-clamp has become common in drug development and safety programmes because it enables efficient and systematic testing of compounds against ion channels during voltage-clamp. It has not, however, been adopted significantly in other important areas of ion channel research, where conventional patch-clamp remains the favoured method. Here we show the wider potential of the multi-well approach with the capability for efficient intracellular solution exchange, describing protocols and success rates for recording from a range of native and primary mammalian cells derived from blood vessels, arthritic joints, and the immune and central nervous systems. The protocol involves preparing a suspension of single cells to be dispensed robotically into 4-8 microfluidic chambers each containing a glass chip with a small aperture. Under automated control, giga-seals and whole-cell access are achieved followed by pre-programmed routines of voltage paradigms and fast extracellular or intracellular solution exchange. Recording from 48 chambers usually takes 1-6 hr depending on the experimental design and yields 16-33 cell recordings. PMID:19197268

A setup for combined multiphoton laser scanning microscopic and multi-electrode patch clamp experiments on brain slices

NASA Astrophysics Data System (ADS)

Helm, P. Johannes; Reppen, Trond; Heggelund, Paul

2009-02-01

Multi Photon Laser Scanning Microscopy (MPLSM) appears today as one of the most powerful experimental tools in cellular neurophysiology, notably in studies of the functional dynamics of signal processing in single neurons. Simultaneous recording of fluorescence signals at high spatial and temporal resolution and electric signals by means of multi electrode patch clamp techniques have provided new paths for the systematic investigation of neuronal mechanisms. In particular, this approach has opened for direct studies of dendritic signal processing in neurons. We report about a setup optimized for simultaneous electrophysiological multi electrode patch clamp and multi photon laser scanning fluorescence microscopic experiments on brain slices. The microscopic system is based on a modified commercially available confocal scanning laser microscope (CLSM). From a technical and operational point of view, two developments are important: Firstly, in order to reduce the workload for the experimentalist, who in general is forced to concentrate on controlling the electrophysiological parameters during the recordings, a system of shutters has been installed together with dedicated electronic modules protecting the photo detectors against destructive light levels caused by erroneous opening or closing of microscopic light paths by the experimentalist. Secondly, the standard detection unit has been improved by installing the photomultiplier tubes (PMT) in a Peltier cooled thermal box shielding the detector from both room temperature and distortions caused by external electromagnetic fields. The electrophysiological system is based on an industrial standard multi patch clamp unit ergonomically arranged around the microscope stage. The electrophysiological and scanning processes can be time coordinated by standard trigger electronics.

Photovoltaic panel clamp

DOEpatents

Mittan, Margaret Birmingham [Oakland, CA; Miros, Robert H. J. [Fairfax, CA; Brown, Malcolm P [San Francisco, CA; Stancel, Robert [Loss Altos Hills, CA

2012-06-05

A photovoltaic panel clamp includes an upper and lower section. The interface between the assembled clamp halves and the module edge is filled by a flexible gasket material, such as EPDM rubber. The gasket preferably has small, finger like protrusions that allow for easy insertion onto the module edge while being reversed makes it more difficult to remove them from the module once installed. The clamp includes mounting posts or an integral axle to engage a bracket. The clamp also may include a locking tongue to secure the clamp to a bracket.

Photovoltaic panel clamp

DOEpatents

Brown, Malcolm P.; Mittan, Margaret Birmingham; Miros, Robert H. J.; Stancel, Robert

2013-03-19

A photovoltaic panel clamp includes an upper and lower section. The interface between the assembled clamp halves and the module edge is filled by a flexible gasket material, such as EPDM rubber. The gasket preferably has small, finger like protrusions that allow for easy insertion onto the module edge while being reversed makes it more difficult to remove them from the module once installed. The clamp includes mounting posts or an integral axle to engage a bracket. The clamp also may include a locking tongue to secure the clamp to a bracket.

Influence of electrical double-layer dispersion forces and size dependency on pull-in instability of clamped microplate immersed in ionic liquid electrolytes

NASA Astrophysics Data System (ADS)

Karimipour, I.; Beni, Yaghoub Tadi; Taheri, N.

2017-10-01

Plate-type clamped microplate is of the most common constructive elements for developing in-liquid-operating devices. While the electromechanical behavior of clamped microplate in non-liquid environments has exclusively been addressed in the literature, no theoretical studies have yet been conducted on precise modeling of the clamped microplate in electrolyte liquid. Herein, the electromechanical response and instability of the clamped microplate immersed in ionic electrolyte media are investigated. The electrochemical force field is determined using double layer theory and linearized Poisson-Boltzmann equation. The presence of dispersion forces, i.e., Casimir and van der Waals attractions, are included in the theoretical model considering the correction due to the presence of liquid media between the interacting surfaces (three-layer model). To this end, a kind of microplate has been designed, i.e., a square microplate with all edges clamped supported. The strain gradient elasticity is employed to model the size-dependent structural behavior of the clamped microplate. To solve the nonlinear constitutive equation of the system, Extended Kantorovich Method, is employed and the pull-in parameter of the microplate are extracted. Impacts of the dispersion forces and size effect on the instability characteristics are discussed as well as the effect of ion concentration and potential ratio. It is found that the significant difference between the pull-in instability parameters in the modified strain gradient theory and the classical theory for thin microplates is merely due to the consideration of size effect parameter in the modified strain gradient theory. To confirm the validity of formulations, the numerical values of the results are compared. The results predicted via the aforementioned approach are in excellent agreement with those in the literature. Some new examples are solved to demonstrate the applicability of the procedure.

Preparation of Drosophila central neurons for in situ patch clamping.

PubMed

Ryglewski, Stefanie; Duch, Carsten

2012-10-15

Short generation times and facile genetic techniques make the fruit fly Drosophila melanogaster an excellent genetic model in fundamental neuroscience research. Ion channels are the basis of all behavior since they mediate neuronal excitability. The first voltage gated ion channel cloned was the Drosophila voltage gated potassium channel Shaker(1,2). Toward understanding the role of ion channels and membrane excitability for nervous system function it is useful to combine powerful genetic tools available in Drosophila with in situ patch clamp recordings. For many years such recordings have been hampered by the small size of the Drosophila CNS. Furthermore, a robust sheath made of glia and collagen constituted obstacles for patch pipette access to central neurons. Removal of this sheath is a necessary precondition for patch clamp recordings from any neuron in the adult Drosophila CNS. In recent years scientists have been able to conduct in situ patch clamp recordings from neurons in the adult brain(3,4) and ventral nerve cord of embryonic(5,6), larval(7,8,9,10), and adult Drosophila(11,12,13,14). A stable giga-seal is the main precondition for a good patch and depends on clean contact of the patch pipette with the cell membrane to avoid leak currents. Therefore, for whole cell in situ patch clamp recordings from adult Drosophila neurons must be cleaned thoroughly. In the first step, the ganglionic sheath has to be treated enzymatically and mechanically removed to make the target cells accessible. In the second step, the cell membrane has to be polished so that no layer of glia, collagen or other material may disturb giga-seal formation. This article describes how to prepare an identified central neuron in the Drosophila ventral nerve cord, the flight motoneuron 5 (MN5(15)), for somatic whole cell patch clamp recordings. Identification and visibility of the neuron is achieved by targeted expression of GFP in MN5. We do not aim to explain the patch clamp technique itself.

Optimal Wonderful Life Utility Functions in Multi-Agent Systems

NASA Technical Reports Server (NTRS)

Wolpert, David H.; Tumer, Kagan; Swanson, Keith (Technical Monitor)

2000-01-01

The mathematics of Collective Intelligence (COINs) is concerned with the design of multi-agent systems so as to optimize an overall global utility function when those systems lack centralized communication and control. Typically in COINs each agent runs a distinct Reinforcement Learning (RL) algorithm, so that much of the design problem reduces to how best to initialize/update each agent's private utility function, as far as the ensuing value of the global utility is concerned. Traditional team game solutions to this problem assign to each agent the global utility as its private utility function. In previous work we used the COIN framework to derive the alternative Wonderful Life Utility (WLU), and experimentally established that having the agents use it induces global utility performance up to orders of magnitude superior to that induced by use of the team game utility. The WLU has a free parameter (the clamping parameter) which we simply set to zero in that previous work. Here we derive the optimal value of the clamping parameter, and demonstrate experimentally that using that optimal value can result in significantly improved performance over that of clamping to zero, over and above the improvement beyond traditional approaches.

Time delay compensation for closed-loop insulin delivery systems: a simulation study.

PubMed

Reboldi, G P; Home, P D; Calabrese, G; Fabietti, P G; Brunetti, P; Massi Benedetti, M

1991-06-01

Closed loop insulin therapy certainly represents the best possible approach to insulin replacement. However, present limitations preclude wider application of the so-called artificial pancreas. Therefore, a thorough understanding of these limitations is needed to design better systems for future long-term use. The present simulation study was design: to obtain better information on the impact of the measurement delay of currently available closed-loop devices both during closed-loop insulin delivery and blood glucose clamp studies, and to design and test a time delay compensator based on the method originally described by O.J. Smith. Simulations were performed on a Compaq Deskpro 486/25 personal computer under MS-DOS operating system using Simnon rel. 3.00 software. There was a direct relationship between measurement delay and amount of insulin delivered, i.e., the longer the delay the higher the insulin dose needed to control a rise in blood glucose; the closed-loop response in presence of a time delay was qualitatively impaired both during insulin delivery and blood glucose clamp studies; time delay compensation was effective in reducing the insulin dose and improving controller stability during the early phase of clamp studies. However, the robustness of a Smith's predictor-based controller should be carefully evaluated before implementation in closed-loop systems can be considered.

Saddle clamp assembly

NASA Technical Reports Server (NTRS)

Belrose, Charles R. (Inventor)

1994-01-01

A saddle clamp assembly is presented. The assembly is comprised of a hollow cylindrical body centered about a longitudinal axis and being diametrically split into semicircular top and bottom sections. Each section has a pair of connection flanges, at opposite ends, that project radially outward. A pair of bolts are retained on the top section flanges and are threadable into nuts retained on the bottom section flanges. A base member is anchored to a central underside portion of the bottom clamp body section and has a pair of connection tabs positioned beneath the bottom clamp body section connection flanges on opposite sides of the clamp axis. A pair of bolts are retained on the base member connection tabs and are threadable into a pair of nuts retainable on a support structure. The connection tab and connection flanges on each side of the clamp body are axially offset in a manner permitting downward installation/removable tool access to the lower bolts past the connection flanges. An elongated retention tether is used to connect the top clamp body section to the balance of the clamp assembly. This prevents loss of the top clamp body section when it is removed from the bottom clamp body section.

Upgrading the Center for Lightweighting Automotive Materials and Processing - a GATE Center of Excellence at the University of Michigan-Dearborn

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

Mallick, P. K.

2012-08-30

The Center for Lightweighting Materials and Processing (CLAMP) was established in September 1998 with a grant from the Department of Energy’s Graduate Automotive Technology Education (GATE) program. The center received the second round of GATE grant in 2005 under the title “Upgrading the Center for Lightweighting Automotive Materials and Processing”. Using the two grants, the Center has successfully created 10 graduate level courses on lightweight automotive materials, integrated them into master’s and PhD programs in Automotive Systems Engineering, and offered them regularly to the graduate students in the program. In addition, the Center has created a web-based lightweight automotive materialsmore » database, conducted research on lightweight automotive materials and organized seminars/symposia on lightweight automotive materials for both academia and industry. The faculty involved with the Center has conducted research on a variety of topics related to design, testing, characterization and processing of lightweight materials for automotive applications and have received numerous research grants from automotive companies and government agencies to support their research. The materials considered included advanced steels, light alloys (aluminum, magnesium and titanium) and fiber reinforced polymer composites. In some of these research projects, CLAMP faculty have collaborated with industry partners and students have used the research facilities at industry locations. The specific objectives of the project during the current funding period (2005 – 2012) were as follows: (1) develop new graduate courses and incorporate them in the automotive systems engineering curriculum (2) improve and update two existing courses on automotive materials and processing (3) upgrade the laboratory facilities used by graduate students to conduct research (4) expand the Lightweight Automotive Materials Database to include additional materials, design case studies and make it more accessible to outside users (5) provide support to graduate students for conducting research on lightweight automotive materials and structures (6) provide industry/university interaction through a graduate certificate program on automotive materials and technology idea exchange through focused seminars and symposia on automotive materials.« less

46 CFR 128.420 - Keel cooler installations.

Code of Federal Regulations, 2013 CFR

2013-10-01

...-metallic hose-clamps may be used at machinery connections if— (1) The clamps are of a corrosion-resistant material; (2) The clamps do not depend on spring tension for their holding power; and (3) Two of the clamps...

High throughput ion-channel pharmacology: planar-array-based voltage clamp.

PubMed

Kiss, Laszlo; Bennett, Paul B; Uebele, Victor N; Koblan, Kenneth S; Kane, Stefanie A; Neagle, Brad; Schroeder, Kirk

2003-02-01

Technological advances often drive major breakthroughs in biology. Examples include PCR, automated DNA sequencing, confocal/single photon microscopy, AFM, and voltage/patch-clamp methods. The patch-clamp method, first described nearly 30 years ago, was a major technical achievement that permitted voltage-clamp analysis (membrane potential control) of ion channels in most cells and revealed a role for channels in unimagined areas. Because of the high information content, voltage clamp is the best way to study ion-channel function; however, throughput is too low for drug screening. Here we describe a novel breakthrough planar-array-based HT patch-clamp technology developed by Essen Instruments capable of voltage-clamping thousands of cells per day. This technology provides greater than two orders of magnitude increase in throughput compared with the traditional voltage-clamp techniques. We have applied this method to study the hERG K(+) channel and to determine the pharmacological profile of QT prolonging drugs.

Satisloh centering technology developments past to present

NASA Astrophysics Data System (ADS)

Leitz, Ernst Michael; Moos, Steffen

2015-10-01

The centering of an optical lens is the grinding of its edge profile or contour in relationship to its optical axis. This is required to ensure that the lens vertex and radial centers are accurately positioned within an optical system. Centering influences the imaging performance and contrast of an optical system. Historically, lens centering has been a purely manual process. Along its 62 years of assembling centering machines, Satisloh introduced several technological milestones to improve the accuracy and quality of this process. During this time more than 2.500 centering machines were assembled. The development went from bell clamping and diamond grinding to Laser alignment, exchange chuckor -spindle systems, to multi axis CNC machines with integrated metrology and automatic loading systems. With the new centering machine C300, several improvements for the clamping and grinding process were introduced. These improvements include a user friendly software to support the operator, a coolant manifold and "force grinding" technology to ensure excellent grinding quality and process stability. They also include an air bearing directly driven centering spindle to provide a large working range of lenses made of all optical materials and diameters from below 10 mm to 300 mm. The clamping force can be programmed between 7 N and 1200 N to safely center lenses made of delicate materials. The smaller C50 centering machine for lenses below 50 mm diameter is available with an optional CNC loading system for automated production.

The computational structural mechanics testbed architecture. Volume 4: The global-database manager GAL-DBM

NASA Technical Reports Server (NTRS)

Wright, Mary A.; Regelbrugge, Marc E.; Felippa, Carlos A.

1989-01-01

This is the fourth of a set of five volumes which describe the software architecture for the Computational Structural Mechanics Testbed. Derived from NICE, an integrated software system developed at Lockheed Palo Alto Research Laboratory, the architecture is composed of the command language CLAMP, the command language interpreter CLIP, and the data manager GAL. Volumes 1, 2, and 3 (NASA CR's 178384, 178385, and 178386, respectively) describe CLAMP and CLIP and the CLIP-processor interface. Volumes 4 and 5 (NASA CR's 178387 and 178388, respectively) describe GAL and its low-level I/O. CLAMP, an acronym for Command Language for Applied Mechanics Processors, is designed to control the flow of execution of processors written for NICE. Volume 4 describes the nominal-record data management component of the NICE software. It is intended for all users.

Detachable clamps for minimal access surgery.

PubMed

Frank, T; Willetts, G J; Cuschieri, A

1995-01-01

A detachable clamp and applicator have been developed for use in minimal access surgical operations involving hollow visceral transection and anastomosis. The clamp has parallel jaws which ensure uniform distribution of the occlusive force. Following application on the bowel, the clamp is released from the applicator, thus freeing the access port. On completion of the anastomosis, the clamp is docked to the applicator, its jaws opened for release from the bowel and then closed prior to removal. The jaws of the clamp are kept closed by a pseudoelastic nickel-titanium (NiTi) alloy spring which imparts advantageous force characteristics when compared to stainless steel. The excellent holding and atraumatic characteristics of the detachable clamp have been confirmed by use in laparoscopic and thoracoscopic surgery on the gastrointestinal tract.

A novel high performance ESD power clamp circuit with a small area

NASA Astrophysics Data System (ADS)

Zhaonian, Yang; Hongxia, Liu; Li, Li; Qingqing, Zhuo

2012-09-01

A MOSFET-based electrostatic discharge (ESD) power clamp circuit with only a 10 ns RC time constant for a 0.18-μm process is proposed. A diode-connected NMOSFET is used to maintain a long delay time and save area. The special structure overcomes other shortcomings in this clamp circuit. Under fast power-up events, the gate voltage of the clamp MOSFET does not rise as quickly as under ESD events, the special structure can keep the clamp MOSFET thoroughly off. Under a falsely triggered event, the special structure can turn off the clamp MOSFET in a short time. The clamp circuit can also reject the power supply noise effectively. Simulation results show that the clamp circuit avoids fast false triggering events such as a 30 ns/1.8 V power-up, maintains a 1.2 μs delay time and a 2.14 μs turn-off time, and reduces to about 70% of the RC time constant. It is believed that the proposed clamp circuit can be widely used in high-speed integrated circuits.

Drum ring removal/installation tool

DOEpatents

Andrade, William Andrew [Livermore, CA

2006-11-14

A handheld tool, or a pair of such tools, such as for use in removing/installing a bolt-type clamping ring on a container barrel/drum, where the clamping ring has a pair of clamping ends each with a throughbore. Each tool has an elongated handle and an elongated lever arm transversely connected to one end of the handle. The lever arm is capable of being inserted into the throughbore of a selected clamping end and leveraged with the handle to exert a first moment on the selected clamping end. Each tool also has a second lever arm, such as a socket with an open-ended slot, which is suspended alongside the first lever arm. The second lever arm is capable of engaging the selected clamping end and being leveraged with the handle to exert a second moment which is orthogonal to the first moment. In this manner, the first and second moments operate to hold the selected clamping end fixed relative to the tool so that the selected clamping end may be controlled with the handle. The pair of clamping ends may also be simultaneously and independently controlled with the use of two handles/tools so as to contort the geometry of the drum clamping ring and enable its removal/installation.

An isolated Hda-clamp complex is functional in the regulatory inactivation of DnaA and DNA replication.

PubMed

Kawakami, Hironori; Su'etsugu, Masayuki; Katayama, Tsutomu

2006-10-01

In Escherichia coli, a complex consisting of Hda and the DNA-loaded clamp-subunit of the DNA polymerase III holoenzyme promotes hydrolysis of DnaA-ATP. The resultant ADP-DnaA is inactive for initiation of chromosomal DNA replication, thereby repressing excessive initiations. As the cellular content of the clamp is 10-100 times higher than that of Hda, most Hda molecules might be complexed with the clamp in vivo. Although Hda predominantly forms irregular aggregates when overexpressed, in the present study we found that co-overexpression of the clamp with Hda enhances Hda solubility dramatically and we efficiently isolated the Hda-clamp complex. A single molecule of the complex appears to consist of two Hda molecules and a single clamp. The complex is competent in DnaA-ATP hydrolysis and DNA replication in the presence of DNA and the clamp deficient subassembly of the DNA polymerase III holoenzyme (pol III*). These findings indicate that the clamp contained in the complex is loaded onto DNA through an interaction with the pol III* and that the Hda activity is preserved in these processes. The complex consisting of Hda and the DNA-unloaded clamp may play a specific role in a process proceeding to the DnaA-ATP hydrolysis in vivo.

A Comprehensive Performance Evaluation of Five Blood Glucose Systems in the Hypo-, Eu-, and Hyperglycemic Range

PubMed Central

Zijlstra, Eric; Heinemann, Lutz; Fischer, Annelie; Kapitza, Christoph

2016-01-01

Background: The objective was to evaluate the performance (in terms of accuracy, precision, and trueness) of 5 CE-certified and commercially available blood glucose (BG) systems (meters plus test strips) using an innovative clinical-experimental study design with a 3-step glucose clamp approach and frequent capillary BG measurements. Methods: Sixteen subjects with type 1 diabetes participated in this open label, single center trial. BG was clamped at 3 levels for 60 minutes each: 60-100-200 mg/dL. Medical staff performed regular finger pricks (up to 10 per BG level) to obtain capillary blood samples for paired BG measurements with the 5 BG systems and a laboratory method as comparison. Results: Three BG systems displayed significantly lower mean absolute relative deviations (MARD) (ACCU-Chek® Aviva Nano [5.4%], BGStar® [5.1%], iBGStar® [5.3%]) than 2 others (FreeStyle InsuLinx® [7.7%], OneTouch Verio®IQ [10.3%]). The measurement precision of all BG systems was comparable, but relative bias was also lower for the 3 systems with lower MARD (ACCU-Chek [1.3%], BGStar [–0.9%], iBGStar [1.0%]) compared with the 2 others (FreeStyle [–7.2%], OneTouch [8.9%]). Conclusions: This 3 range glucose clamp approach enables a systematic performance evaluation of BG systems under controlled and reproducible conditions. The random error of the tested BG systems was comparable, but some showed a lower systematic error than others. These BG systems allow an accurate glucose measurement at low, normal and high BG levels. PMID:27605592

A Comprehensive Performance Evaluation of Five Blood Glucose Systems in the Hypo-, Eu-, and Hyperglycemic Range.

PubMed

Zijlstra, Eric; Heinemann, Lutz; Fischer, Annelie; Kapitza, Christoph

2016-11-01

The objective was to evaluate the performance (in terms of accuracy, precision, and trueness) of 5 CE-certified and commercially available blood glucose (BG) systems (meters plus test strips) using an innovative clinical-experimental study design with a 3-step glucose clamp approach and frequent capillary BG measurements. Sixteen subjects with type 1 diabetes participated in this open label, single center trial. BG was clamped at 3 levels for 60 minutes each: 60-100-200 mg/dL. Medical staff performed regular finger pricks (up to 10 per BG level) to obtain capillary blood samples for paired BG measurements with the 5 BG systems and a laboratory method as comparison. Three BG systems displayed significantly lower mean absolute relative deviations (MARD) (ACCU-Chek® Aviva Nano [5.4%], BGStar® [5.1%], iBGStar® [5.3%]) than 2 others (FreeStyle InsuLinx® [7.7%], OneTouch Verio®IQ [10.3%]). The measurement precision of all BG systems was comparable, but relative bias was also lower for the 3 systems with lower MARD (ACCU-Chek [1.3%], BGStar [-0.9%], iBGStar [1.0%]) compared with the 2 others (FreeStyle [-7.2%], OneTouch [8.9%]). This 3 range glucose clamp approach enables a systematic performance evaluation of BG systems under controlled and reproducible conditions. The random error of the tested BG systems was comparable, but some showed a lower systematic error than others. These BG systems allow an accurate glucose measurement at low, normal and high BG levels. © 2016 Diabetes Technology Society.

Insect Optic Glomeruli-Exploration of a Universal Circuit for Sensorimotor Processing

DTIC Science & Technology

2011-01-25

09 to 2-28-10. We have successfully achieved the first recordings from any laboratory of the small palisade output neurons from the lobula of...glomeruli. Using infrared illumination and optics, the cell bodies of such clones are directly observed. A patch clamp recording electrode, filled...neuron and electrolyte of the electrode has been established, the cell is recorded during the presentation of a sequence of visual stimuli: stripes

Stress-Strain Properties of SIFCON in Uniaxial Compression and Tension

DTIC Science & Technology

1988-08-01

direction act as contacting beams whereas fibers aligned parallel to the loading direction act as individual columns . The combination of fiber-to-fiber...applicable to the study of SIFCON. These include such topics as the influence of strain rate on composite behavior, cyclic loading response, fiber-to-matrix...the specimen are shown in Figure 17. The grips consisted of self-clamping steel plates and a universal joint connection to the loading machine which

Viscoelastic Properties of Advanced Polymer Composites for Ballistic Protective Applications

DTIC Science & Technology

1994-09-01

ofthe Damaged Sample 78 Figure 69: Fracture Surface of Damage Area Near the Point of Penetration 79 Figure 70. Closer View ofthe Damaged Area...LIST OF TABLES Table 1. Basic Mechanical Properties of the Materials 6 Table 2. Initial DMA Test Results 23 Table 3. Flexural Three Point Bend... point bend testing was conducted using an Instron 1127 Universal Tester to verify the DMA test method and specimen clamping configuration. Interfacial

Electrostatic Interactions at the Dimer Interface Stabilize the E. coli β Sliding Clamp.

PubMed

Purohit, Anirban; England, Jennifer K; Douma, Lauren G; Tondnevis, Farzaneh; Bloom, Linda B; Levitus, Marcia

2017-08-22

Sliding clamps are ring-shaped oligomeric proteins that encircle DNA and associate with DNA polymerases for processive DNA replication. The dimeric Escherichia coli β-clamp is closed in solution but must adopt an open conformation to be assembled onto DNA by a clamp loader. To determine what factors contribute to the stability of the dimer interfaces in the closed conformation and how clamp dynamics contribute to formation of the open conformation, we identified conditions that destabilized the dimer and measured the effects of these conditions on clamp dynamics. We characterized the role of electrostatic interactions in stabilizing the β-clamp interface. Increasing salt concentration results in decreased dimer stability and faster subunit dissociation kinetics. The equilibrium dissociation constant of the dimeric clamp varies with salt concentration as predicted by simple charge-screening models, indicating that charged amino acids contribute to the remarkable stability of the interface at physiological salt concentrations. Mutation of a charged residue at the interface (Arg-103) weakens the interface significantly, whereas effects are negligible when a hydrophilic (Ser-109) or a hydrophobic (Ile-305) amino acid is mutated instead. It has been suggested that clamp opening by the clamp loader takes advantage of spontaneous opening-closing fluctuations at the clamp's interface, but our time-resolved fluorescence and fluorescence correlation experiments rule out conformational fluctuations that lead to a significant fraction of open states. Copyright © 2017 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Welding fixture for joining bar-wound stator conductors

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

De Souza, Urban J.; Rhoads, Frederick W.; Hanson, Justin

A fixture assembly for welding a plurality of stator wire end pairs may include an anvil, a movable clamp configured to translate between an unclamped state and a clamped state, a first grounding electrode, and a second grounding electrode. The movable clamp may be configured to urge the plurality of stator wire ends against the anvil when in the clamped state. The moveable clamp includes a separator feature that generally extends toward the anvil. Each of the first grounding electrode and second grounding electrodes may be configured to translate between a clamped state and an unclamped state. When in themore » clamped state, each of the first and second grounding electrodes is configured to urge a pair of the plurality of stator wire end pairs against the separator feature.« less

Hda Monomerization by ADP Binding Promotes Replicase Clamp-mediated DnaA-ATP Hydrolysis*S⃞

PubMed Central

Su'etsugu, Masayuki; Nakamura, Kenta; Keyamura, Kenji; Kudo, Yuka; Katayama, Tsutomu

2008-01-01

ATP-DnaA is the initiator of chromosomal replication in Escherichia coli, and the activity of DnaA is regulated by the regulatory inactivation of the DnaA (RIDA) system. In this system, the Hda protein promotes DnaA-ATP hydrolysis to produce inactive ADP-DnaA in a mechanism that is mediated by the DNA-loaded form of the replicase sliding clamp. In this study, we first revealed that hda translation uses an unusual initiation codon, CUG, located downstream of the annotated initiation codon. The CUG initiation codon could be used for restricting the Hda level, as this initiation codon has a low translation efficiency, and the cellular Hda level is only ∼100 molecules per cell. Hda translated using the correct reading frame was purified and found to have a high RIDA activity in vitro. Moreover, we found that Hda has a high affinity for ADP but not for other nucleotides, including ATP. ADP-Hda was active in the RIDA system in vitro and stable in a monomeric state, whereas apo-Hda formed inactive homomultimers. Both ADP-Hda and apo-Hda could form complexes with the DNA-loaded clamp; however, only ADP-Hda-DNA-clamp complexes were highly functional in the following interaction with DnaA. Formation of ADP-Hda was also observed in vivo, and mutant analysis suggested that ADP binding is crucial for cellular Hda activity. Thus, we propose that ADP is a crucial Hda ligand that promotes the activated conformation of the protein. ADP-dependent monomerization might enable the arginine finger of the Hda AAA+ domain to be accessible to ATP bound to the DnaA AAA+ domain. PMID:18977760

Hda monomerization by ADP binding promotes replicase clamp-mediated DnaA-ATP hydrolysis.

PubMed

Su'etsugu, Masayuki; Nakamura, Kenta; Keyamura, Kenji; Kudo, Yuka; Katayama, Tsutomu

2008-12-26

ATP-DnaA is the initiator of chromosomal replication in Escherichia coli, and the activity of DnaA is regulated by the regulatory inactivation of the DnaA (RIDA) system. In this system, the Hda protein promotes DnaA-ATP hydrolysis to produce inactive ADP-DnaA in a mechanism that is mediated by the DNA-loaded form of the replicase sliding clamp. In this study, we first revealed that hda translation uses an unusual initiation codon, CUG, located downstream of the annotated initiation codon. The CUG initiation codon could be used for restricting the Hda level, as this initiation codon has a low translation efficiency, and the cellular Hda level is only approximately 100 molecules per cell. Hda translated using the correct reading frame was purified and found to have a high RIDA activity in vitro. Moreover, we found that Hda has a high affinity for ADP but not for other nucleotides, including ATP. ADP-Hda was active in the RIDA system in vitro and stable in a monomeric state, whereas apo-Hda formed inactive homomultimers. Both ADP-Hda and apo-Hda could form complexes with the DNA-loaded clamp; however, only ADP-Hda-DNA-clamp complexes were highly functional in the following interaction with DnaA. Formation of ADP-Hda was also observed in vivo, and mutant analysis suggested that ADP binding is crucial for cellular Hda activity. Thus, we propose that ADP is a crucial Hda ligand that promotes the activated conformation of the protein. ADP-dependent monomerization might enable the arginine finger of the Hda AAA+ domain to be accessible to ATP bound to the DnaA AAA+ domain.

Renal Vascular Clamp Placement: A Potential Cause of Incomplete Hilar Control during Partial Nephrectomy.

PubMed

Tryon, David; Myklak, Kristene; Alsyouf, Muhannad; Conceicao, Carol; Peplinski, Brandon; Arenas, Javier L; Faaborg, Daniel; Ruckle, Herbert C; Baldwin, D Duane

2016-03-01

Previous benchtop studies have shown that robotic bulldog clamps provide incomplete vascular control of a Penrose drain. We determined the efficacy of robotic and laparoscopic bulldog clamps to ensure hemostasis on the human renal artery. The effect of clamp position on vascular control was also examined. Fresh human cadaveric renal arteries were used to determine the leak point pressure of 7 bulldog clamps from a total of 3 manufacturers. Five trials were performed per clamp at 4 locations, including the fulcrum, proximal, middle and distal positions. Comparison was done using the Kruskal-Wallis test with p <0.05 considered significant. None of the bulldog clamps leaked at a pressure less than 215 mm Hg when applied at the proximal, middle or distal position. In general leak point pressure decreased as the artery was positioned more distal along the clamp. The exception was when the vessel was placed at the fulcrum position. At that position 80% to 100% of trials with the Klein laparoscopic, 100% with the Klein robotic (Klein Robotic, San Antonio, Texas) and 60% to 80% with the Scanlan robotic (Scanlan International, Saint Paul, Minnesota) clamp leaked at pressure below 215 mm Hg. Each vascular clamp adequately occluded flow at physiological pressure when placed at the proximal, middle or distal position. Furthermore, these results demonstrate that there is leakage at physiological pressure when the artery is placed at the fulcrum of certain clamp types. These results suggest that applying a bulldog clamp at the fulcrum could potentially lead to inadequate vessel occlusion and intraoperative bleeding. Copyright © 2016 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

A comparison between the minimal model and the glucose clamp in the assessment of insulin sensitivity across the spectrum of glucose tolerance. Insulin Resistance Atherosclerosis Study.

PubMed

Saad, M F; Anderson, R L; Laws, A; Watanabe, R M; Kades, W W; Chen, Y D; Sands, R E; Pei, D; Savage, P J; Bergman, R N

1994-09-01

An insulin-modified frequently sampled intravenous glucose tolerance test (FSIGTT) with minimal model analysis was compared with the glucose clamp in 11 subjects with normal glucose tolerance (NGT), 20 with impaired glucose tolerance (IGT), and 24 with non-insulin-dependent diabetes mellitus (NIDDM). The insulin sensitivity index (SI) was calculated from FSIGTT using 22- and 12-sample protocols (SI(22) and SI(12), respectively). Insulin sensitivity from the clamp was expressed as SI(clamp) and SIP(clamp). Minimal model parameters were similar when calculated with SI(22) and SI(12). SI could not be distinguished from 0 in approximately 50% of diabetic patients with either protocol. SI(22) correlated significantly with SI(clamp) in the whole group (r = 0.62), and in the NGT (r = 0.53), IGT (r = 0.48), and NIDDM (r = 0.41) groups (P < 0.05 for each). SI(12) correlated significantly with SI(clamp) in the whole group (r = 0.55, P < 0.001) and in the NGT (r = 0.53, P = 0.046) and IGT (r = 0.58, P = 0.008) but not NIDDM (r = 0.30, P = 0.085) groups. When SI(22), SI(clamp), and SIP(clamp) were expressed in the same units, SI(22) was 66 +/- 5% (mean +/- SE) and 50 +/- 8% lower than SI(clamp) and SIP(clamp), respectively. Thus, minimal model analysis of the insulin-modified FSIGTT provides estimates of insulin sensitivity that correlate significantly with those from the glucose clamp. The correlation was weaker, however, in NIDDM. The insulin-modified FSIGTT can be used as a simple test for assessment of insulin sensitivity in population studies involving nondiabetic subjects. Additional studies are needed before using this test routinely in patients with NIDDM.

Arterial waves in humans during peripheral vascular surgery.

PubMed

Khir, A W; Henein, M Y; Koh, T; Das, S K; Parker, K H; Gibson, D G

2001-12-01

The purpose of this study was to investigate the effect of aortic clamping on arterial waves during peripheral vascular surgery. We measured pressure and velocity simultaneously in the ascending aorta, in ten patients (70+/-5 years) with aortic-iliac disease intra-operatively. Pressure was measured using a catheter tip manometer, and velocity was measured using Doppler ultrasound. Data were collected before aortic clamping, during aortic clamping and after unclamping. Hydraulic work in the aortic root was calculated from the measured data, the reflected waves were determined by wave-intensity analysis and wave speed was determined by the PU-loop (pressure-velocity-loop) method; a new technique based on the 'water-hammer' equation. The wave speed is approx. 32% (P<0.05) higher during clamping than before clamping. Although the peak intensity of the reflected wave does not alter with clamping, it arrives 30 ms (P<0.05) earlier and its duration is 25% (P<0.05) longer than before clamping. During clamping, left ventricule (LV) hydraulic systolic work and the energy carried by the reflected wave increased by 27% (P<0.05) and 20% (P<0.05) respectively, compared with before clamping. The higher wave speed during clamping explains the earlier arrival of the reflected waves suggesting an increase in the afterload, since the LV has to overcome earlier reflected compression waves. The longer duration of the reflected wave during clamping is associated with an increase in the total energy carried by the wave, which causes an increase in hydraulic work. Increased hydraulic work during clamping may increase LV oxygen consumption, provoke myocardial ischaemia and hence contribute to the intra-operative impairment of LV function known in patients with peripheral vascular disease.

Clamp-mount device

NASA Technical Reports Server (NTRS)

Clark, K. H. (Inventor)

1983-01-01

A clamp-mount device is disclosed for mounting equipment to an associated I-beam and the like structural member of the type having oppositely extending flanges wherein the device comprises a base and a pair of oppositely facing clamping members carried diagonally on the base clamping flanges therebetween and having flange receiving openings facing one another. Lock means are carried diagonally by the base opposite the clamping members locking the flanges in the clamping members. A resilient hub is carried centrally of the base engaging and biasing a back side of the flanges maintaining tightly clamped and facilitating use on vertical as well as horizontal members. The base turns about the hub to receive the flanges within the clamping members. Equipment may be secured to the base by any suitable means such as bolts in openings. Slidable gate latches secure the hinged locks in an upright locking position. The resilient hub includes a recess opening formed in the base and a rubber-like pad carried in this opening being depressably and rotatably carried therein.

The RNA polymerase clamp interconverts dynamically among three states and is stabilized in a partly closed state by ppGpp.

PubMed

Duchi, Diego; Mazumder, Abhishek; Malinen, Anssi M; Ebright, Richard H; Kapanidis, Achillefs N

2018-06-06

RNA polymerase (RNAP) contains a mobile structural module, the 'clamp,' that forms one wall of the RNAP active-center cleft and that has been linked to crucial aspects of the transcription cycle, including promoter melting, transcription elongation complex stability, transcription pausing, and transcription termination. Using single-molecule FRET on surface-immobilized RNAP molecules, we show that the clamp in RNAP holoenzyme populates three distinct conformational states and interconvert between these states on the 0.1-1 s time-scale. Similar studies confirm that the RNAP clamp is closed in open complex (RPO) and in initial transcribing complexes (RPITC), including paused initial transcribing complexes, and show that, in these complexes, the clamp does not exhibit dynamic behaviour. We also show that, the stringent-response alarmone ppGpp, which reprograms transcription during amino acid starvation stress, selectively stabilizes the partly-closed-clamp state and prevents clamp opening; these results raise the possibility that ppGpp controls promoter opening by modulating clamp dynamics.

Structural analysis of a eukaryotic sliding DNA clamp-clamp loadercomplex.

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

Bowman, Gregory D.; O'Donnell, Mike; Kuriyan, John

2006-06-17

Sliding clamps are ring-shaped proteins that encircle DNA and confer high processivity on DNA polymerases. Here we report the crystal structure of the five-protein clamp loader complex (replication factor-C, RFC) of the yeast Saccharomyces cerevisiae, bound to the sliding clamp (proliferating cell nuclear antigen, PCNA). Tight interfacial coordination of the ATP analogue ATP-?-S by RFC results in a spiral arrangement of the ATPase domains of the clamp loader above the PCNA ring. Placement of a model for primed DNA within the central hole of PCNA reveals a striking correspondence between the RFC spiral and the grooves of the DNA doublemore » helix. This model, in which the clamp loader complex locks onto primed DNA in a screw-cap-like arrangement, provides a simple explanation for the process by which the engagement of primer-template junctions by the RFC:PCNA complex results in ATP hydrolysis and release of the sliding clamp on DNA.« less

Investigation of chaos and its control in a Duffing-type nano beam model

NASA Astrophysics Data System (ADS)

Jha, Abhishek Kumar; Dasgupta, Sovan Sundar

2018-04-01

The prediction of chaos of a nano beam with harmonic excitation is investigated. Using the Galerkin method the nonlinear lumped model of a clamped-clamped nano beam with nonlinear cubic stiffness is obtained. This is a Duffing system with hardening type of nonlinearity. Based on the energy function and the phase portrait of the system, the resonator dynamics is categorized into four situations in which Using Malnikov function, an analytical criterion for homoclinic intersection in the form of inequality is written in terms of the system parameters. A numerical study including largest lyapunov exponent, Poincare diagram and phase portrait confirm the analytical prediction of chaos and effect of forcing amplitude. Subsequently, a linear velocity feedback controller is introduced into the system to successfully control the chaotic motion of the system at a faster rate at larger value of gain parameter.

Evaluation of Introduction of a Delayed Cord Clamping Protocol for Premature Neonates in a High-Volume Maternity Center.

PubMed

Liu, Lilly Y; Feinglass, Joe M; Khan, Janine Y; Gerber, Susan E; Grobman, William A; Yee, Lynn M

2017-05-01

To evaluate adherence to a delayed cord clamping protocol for preterm births in the first 2 years after its introduction, perform a quality improvement assessment, and determine neonatal outcomes associated with protocol implementation and adherence. This is a retrospective cohort study of women delivering singleton neonates at 23-32 weeks of gestation in the 2 years before (preprotocol) and 2 years after (postprotocol) introduction of a 30-second delayed cord clamping protocol at a large-volume academic center. This policy was communicated to obstetric and pediatric health care providers and nurses and reinforced with intermittent educational reviews. Barriers to receiving delayed cord clamping were assessed using χ tests and multivariable logistic regression. Neonatal outcomes then were compared between all neonates in the preprotocol period and all neonates in the postprotocol period and between all neonates in the preprotocol period and neonates receiving delayed cord clamping in the postprotocol period using multivariable linear and logistic regression analyses. Of the 427 eligible neonates, 187 were born postprotocol. Of these, 53.5% (n=100) neonates received delayed cord clamping according to the protocol. The rate of delayed cord clamping preprotocol was 0%. Protocol uptake and frequency of delayed cord clamping increased over the 2 years after its introduction. In the postprotocol period, cesarean delivery was the only factor independently associated with failing to receive delayed cord clamping (adjusted odds ratio [OR] 0.49, 95% confidence interval [CI] 0.25-0.96). In comparison with the preprotocol period, those who received delayed cord clamping in the postprotocol period had significantly higher birth hematocrit (β=2.46, P=.007) and fewer blood transfusions in the first week of life (adjusted OR 0.49, 95% CI 0.25-0.96). After introduction of an institutional delayed cord clamping protocol followed by continued health care provider education and quality feedback, the frequency of delayed cord clamping progressively increased. Compared with historical controls, performing delayed cord clamping in eligible preterm neonates was associated with improved neonatal hematologic indices, demonstrating the effectiveness of delayed cord clamping in a large-volume maternity unit.

Ion channel electrophysiology via integrated planar patch-clamp chip with on-demand drug exchange.

PubMed

Chen, Chang-Yu; Tu, Ting-Yuan; Jong, De-Shien; Wo, Andrew M

2011-06-01

Planar patch clamp has revolutionized characterization of ion channel behavior in drug discovery primarily via advancement in high throughput. Lab use of planar technology, however, addresses different requirements and suffers from inflexibility to enable wide range of interrogation via a single cell. This work presents integration of planar patch clamp with microfluidics, achieving multiple solution exchanges for tailor-specific measurement and allowing rapid replacement of the cell-contacting aperture. Studies via endogenously expressed ion channels in HEK 293T cells were commenced to characterize the device. Results reveal the microfluidic concentration generator produces distinct solution/drug combination/concentrations on-demand. Volume-regulated chloride channel and voltage-gated potassium channels in HEK 293T cells immersed in generated solutions under various osmolarities or drug concentrations show unique channel signature under specific condition. Excitation and blockage of ion channels in a single cell was demonstrated via serial solution exchange. Robustness of the reversible bonding and ease of glass substrate replacement were proven via repeated usage of the integrated device. The present approach reveals the capability and flexibility of integrated microfluidic planar patch-clamp system for ion channel assays. Copyright © 2011 Wiley Periodicals, Inc.

The design, fabrication and delivery of a spacelab neutral buoyancy Instrument Pointing System (IPS) mockup. [underwater training simulator

NASA Technical Reports Server (NTRS)

Vanvalkenburgh, C. N.

1984-01-01

Underwater simulations of EVA contingency operations such as manual jettison, payload disconnect, and payload clamp actuation were used to define crew aid needs and mockup pecularities and characteristics to verify the validity of simulation using the trainer. A set of mockup instrument pointing system tests was conducted and minor modifications and refinements were made. Flight configuration struts were tested and verified to be operable by the flight crew. Tasks involved in developing the following end items are described: IPS gimbal system, payload, and payload clamp assembly; the igloos (volumetric); spacelab pallets, experiments, and hardware; experiment, and hardware; experiment 7; and EVA hand tools, support hardware (handrails and foot restraints). The test plan preparation and test support are also covered.

Force-Measuring Clamp

NASA Technical Reports Server (NTRS)

Nunnelee, Mark (Inventor)

2004-01-01

A precision clamp that accurately measures force over a wide range of conditions is described. Using a full bridge or other strain gage configuration. the elastic deformation of the clamp is measured or detected by the strain gages. Thc strain gages transmit a signal that corresponds to the degree of stress upon the clamp. Thc strain gage signal is converted to a numeric display. Calibration is achieved by ero and span potentiometers which enable accurate measurements by the force-measuring clamp.

System and Apparatus for Deploying a Satellite

NASA Technical Reports Server (NTRS)

Santos, Luis H. (Inventor); Hudeck, John D. (Inventor)

2016-01-01

A frictionless satellite constraint system is provided. The constraint system includes at least one clamp bar configured to restrain a satellite within the constraint system in an axial direction. The constraint system also includes a plurality of pins configured to restrain the satellite within the constraint system in a lateral direction.

Delayed clamping of the umbilical cord after delivery and implications for public cord blood banking.

PubMed

Allan, David S; Scrivens, Nicholas; Lawless, Tiffany; Mostert, Karen; Oppenheimer, Lawrence; Walker, Mark; Petraszko, Tanya; Elmoazzen, Heidi

2016-03-01

Public banking of umbilical cord blood units (CBUs) containing higher numbers of cells ensures timely engraftment after transplantation for increasing numbers of patients. Delayed clamping of the umbilical cord after birth may benefit some infants by preventing iron deficiency. Implications of delayed cord clamping for public cord blood banking remains unclear. CBUs collected by Canadian Blood Services at one collection site between November 1, 2014, and March 17, 2015, were analyzed. The delay in cord clamping after birth was timed and classified as "no delay," 20 to 60 seconds, more than 60 seconds, or more than 120 seconds. Of 367 collections, 100 reported no delay in clamping while clamping was delayed by 20 to 60 seconds (n = 69), more than 60 seconds (n = 98), or more than 120 seconds (n = 100) in the remaining cases. The mean volume and total nucleated cells (TNCs) in units with no delay in clamping were significantly greater than mean volumes for all categories of delayed clamping (Tukey's test, p < 0.05 for each comparison). The proportion of units with more than 1.5 × 10(9) TNCs was significantly reduced when clamping was delayed (p = 5.5 × 10(-8) ). The difference was most marked for cords that were clamped more than 120 seconds after delivery (6.2% compared with 39%). Delayed cord clamping greatly diminishes the volume and TNC count of units collected for a public cord blood bank. Creating an inventory of CBUs with high TNC content may take more time than expected. © 2015 AABB.

One-channel Cell-attached Patch-clamp Recording

PubMed Central

Maki, Bruce A.; Cummings, Kirstie A.; Paganelli, Meaghan A.; Murthy, Swetha E.; Popescu, Gabriela K.

2014-01-01

Ion channel proteins are universal devices for fast communication across biological membranes. The temporal signature of the ionic flux they generate depends on properties intrinsic to each channel protein as well as the mechanism by which it is generated and controlled and represents an important area of current research. Information about the operational dynamics of ion channel proteins can be obtained by observing long stretches of current produced by a single molecule. Described here is a protocol for obtaining one-channel cell-attached patch-clamp current recordings for a ligand gated ion channel, the NMDA receptor, expressed heterologously in HEK293 cells or natively in cortical neurons. Also provided are instructions on how to adapt the method to other ion channels of interest by presenting the example of the mechano-sensitive channel PIEZO1. This method can provide data regarding the channel’s conductance properties and the temporal sequence of open-closed conformations that make up the channel’s activation mechanism, thus helping to understand their functions in health and disease. PMID:24961614

40 CFR 63.801 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... source implementing controls, such as a control system. Building enclosure means a building housing a... without further clamping, pressure, or airing. Continuous coater means a finishing system that... pollutant introduced to the control device. Control system means the combination of capture and control...

30 CFR 75.605 - Clamping of trailing cables to equipment.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Clamping of trailing cables to equipment. 75... MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Trailing Cables § 75.605 Clamping of trailing cables to equipment. [Statutory Provisions] Trailing cables shall be clamped to...

Thermal Interface Evaluation of Heat Transfer from a Pumped Loop to Titanium-Water Thermosyphons

NASA Technical Reports Server (NTRS)

Jaworske, Donald A.; Sanzi, James L.; Gibson, Marc A.; Sechkar, Edward A.

2009-01-01

Titanium-water thermosyphons are being considered for use in the heat rejection system for lunar outpost fission surface power. Key to their use is heat transfer between a closed loop heat source and the heat pipe evaporators. This work describes laboratory testing of several interfaces that were evaluated for their thermal performance characteristics, in the temperature range of 350 to 400 K, utilizing a water closed loop heat source and multiple thermosyphon evaporator geometries. A gas gap calorimeter was used to measure heat flow at steady state. Thermocouples in the closed loop heat source and on the evaporator were used to measure thermal conductance. The interfaces were in two generic categories, those immersed in the water closed loop heat source and those clamped to the water closed loop heat source with differing thermal conductive agents. In general, immersed evaporators showed better overall performance than their clamped counterparts. Selected clamped evaporator geometries offered promise.

Characterization of active hair-bundle motility by a mechanical-load clamp

NASA Astrophysics Data System (ADS)

Salvi, Joshua D.; Maoiléidigh, Dáibhid Ó.; Fabella, Brian A.; Tobin, Mélanie; Hudspeth, A. J.

2015-12-01

Active hair-bundle motility endows hair cells with several traits that augment auditory stimuli. The activity of a hair bundle might be controlled by adjusting its mechanical properties. Indeed, the mechanical properties of bundles vary between different organisms and along the tonotopic axis of a single auditory organ. Motivated by these biological differences and a dynamical model of hair-bundle motility, we explore how adjusting the mass, drag, stiffness, and offset force applied to a bundle control its dynamics and response to external perturbations. Utilizing a mechanical-load clamp, we systematically mapped the two-dimensional state diagram of a hair bundle. The clamp system used a real-time processor to tightly control each of the virtual mechanical elements. Increasing the stiffness of a hair bundle advances its operating point from a spontaneously oscillating regime into a quiescent regime. As predicted by a dynamical model of hair-bundle mechanics, this boundary constitutes a Hopf bifurcation.

The computational structural mechanics testbed architecture. Volume 5: The Input-Output Manager DMGASP

NASA Technical Reports Server (NTRS)

Felippa, Carlos A.

1989-01-01

This is the fifth of a set of five volumes which describe the software architecture for the Computational Structural Mechanics Testbed. Derived from NICE, an integrated software system developed at Lockheed Palo Alto Research Laboratory, the architecture is composed of the command language (CLAMP), the command language interpreter (CLIP), and the data manager (GAL). Volumes 1, 2, and 3 (NASA CR's 178384, 178385, and 178386, respectively) describe CLAMP and CLIP and the CLIP-processor interface. Volumes 4 and 5 (NASA CR's 178387 and 178388, respectively) describe GAL and its low-level I/O. CLAMP, an acronym for Command Language for Applied Mechanics Processors, is designed to control the flow of execution of processors written for NICE. Volume 5 describes the low-level data management component of the NICE software. It is intended only for advanced programmers involved in maintenance of the software.

Storage containers for radioactive material

DOEpatents

Groh, Edward F.; Cassidy, Dale A.; Dates, Leon R.

1981-01-01

A radioactive material storage system for use in the laboratory having a flat base plate with a groove in one surface thereof and a hollow pedestal extending perpendicularly away from the other surface thereof, a sealing gasket in the groove, a cover having a filter therein and an outwardly extending flange which fits over the plate, the groove and the gasket, and a clamp for maintaining the cover and the plate sealed together, whereby the plate and the cover and the clamp cooperate to provide a storage area for radioactive material readily accessible for use or

Mechanical support of a ceramic gas turbine vane ring

DOEpatents

Shi, Jun; Green, Kevin E.; Mosher, Daniel A.; Holowczak, John E.; Reinhardt, Gregory E.

2010-07-27

An assembly for mounting a ceramic turbine vane ring onto a turbine support casing comprises a first metal clamping ring and a second metal clamping ring. The first metal clamping ring is configured to engage with a first side of a tab member of the ceramic turbine vane ring. The second metal clamping ring is configured to engage with a second side of the tab member such that the tab member is disposed between the first and second metal clamping rings.

Active energy recovery clamping circuit to improve the performance of power converters

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

Whitaker, Bret; Barkley, Adam

2017-05-09

A regenerative clamping circuit for a power converter using clamping diodes to transfer charge to a clamping capacitor and a regenerative converter to transfer charge out of the clamping capacitor back to the power supply input connection. The regenerative converter uses a switch connected to the midpoint of a series connected inductor and capacitor. The ends of the inductor and capacitor series are connected across the terminals of the power supply to be in parallel with the power supply.

Payload Launch Lock Mechanism

NASA Technical Reports Server (NTRS)

Young, Ken (Inventor); Hindle, Timothy (Inventor)

2014-01-01

A payload launch lock mechanism includes a base, a preload clamp, a fastener, and a shape memory alloy (SMA) actuator. The preload clamp is configured to releasibly restrain a payload. The fastener extends, along an axis, through the preload clamp and into the base, and supplies a force to the preload clamp sufficient to restrain the payload. The SMA actuator is disposed between the base and the clamp. The SMA actuator is adapted to receive electrical current and is configured, upon receipt of the electrical current, to supply a force that causes the fastener to elongate without fracturing. The preload clamp, in response to the fastener elongation, either rotates or pivots to thereby release the payload.

High Efficiency Automatic-Power-Controlled and Gain-Clamped EDFA for Broadband Passive Optical Networking Systems

NASA Astrophysics Data System (ADS)

Shen, Jyi-Lai; Wei, Shui-Ken; Lin, Chin-Yuan; Iong Li, Ssu; Huang, Chih-Chuan

2010-04-01

The configuration of a simple improved high efficiency automatic-power-controlled and gain-clamped EDFA (APC-GC-EDFA) for broadband passive optical networking systems (BPON) is presented here. In order to compensate the phase and amplitude variation due to the different distance between the optical line terminal (OLT) and optical network units (ONU), the APC-GC-EDFA need to be employed. A single 980 nm laser module is employed as the primary pump. To extend the bandwidth, all C-band ASE is recycled as the secondary pump to enhance the gain efficiency. An electrical feedback circuit is used as a multi-wavelength channel transmitter monitor for the automatic power control to improve the gain-flattened flatness for stable amplification. The experimental results prove that the EDFA system can provide flatter clamped gain in both C-band and L-band configurations. The gain flatness wavelength ranging from 1530 to 1610 nm is within 32.83 ± 0.64 dB, i.e. below 1.95 %. The gains are clamped at 33.85 ± 0.65 dB for the input signal power of -40 dBm to -10 dBm. The range of noise figure is between 6.37 and 6.56, which is slightly lower compared to that of unclamped amplifiers. This will be very useful for measuring the gain flatness of APC-GC-EDFA. Finally, we have also demonstrated the records of the overall simultaneous dynamics measurements for the new system stabilization. The carrier to noise ratio (CNR) is 49.5 to 50.8 dBc which is above the National Television System Committee (NTSC) standard of 43 dBc, and both composite second order (CSO) 69.2 to 71.5 dBc and composite triple beat (CTB) of 69.8 to 72.2 dBc are above 53 dBc. The recorded corresponding rise-time of 1.087 ms indicates that the system does not exhibit any overshoot of gain or ASE variation due to the signal at the beginning of the pulse.

21 CFR 876.5160 - Urological clamp for males.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Urological clamp for males. 876.5160 Section 876...) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Therapeutic Devices § 876.5160 Urological clamp for males. (a) Identification. A urological clamp for males is a device used to close the urethra of a male to...

Experimental Modal Analysis of Rectangular and Circular Beams

ERIC Educational Resources Information Center

Emory, Benjamin H.; Zhu, Wei Dong

2006-01-01

Analytical and experimental methods are used to determine the natural frequencies and mode shapes of Aluminum 6061-T651 beams with rectangular and circular cross-sections. A unique test stand is developed to provide the rectangular beam with different boundary conditions including clamped-free, clamped-clamped, clamped-pinned, and pinned-pinned.…

Solutions for transients in arbitrarily branching cables: III. Voltage clamp problems.

PubMed

Major, G

1993-07-01

Branched cable voltage recording and voltage clamp analytical solutions derived in two previous papers are used to explore practical issues concerning voltage clamp. Single exponentials can be fitted reasonably well to the decay phase of clamped synaptic currents, although they contain many underlying components. The effective time constant depends on the fit interval. The smoothing effects on synaptic clamp currents of dendritic cables and series resistance are explored with a single cylinder + soma model, for inputs with different time courses. "Soma" and "cable" charging currents cannot be separated easily when the soma is much smaller than the dendrites. Subtractive soma capacitance compensation and series resistance compensation are discussed. In a hippocampal CA1 pyramidal neurone model, voltage control at most dendritic sites is extremely poor. Parameter dependencies are illustrated. The effects of series resistance compound those of dendritic cables and depend on the "effective capacitance" of the cell. Plausible combinations of parameters can cause order-of-magnitude distortions to clamp current waveform measures of simulated Schaeffer collateral inputs. These voltage clamp problems are unlikely to be solved by the use of switch clamp methods.

Optimal Surgical Therapy in a Porcine (Sus scrofa) Model of Extra-Thoracic Penetrating Trauma Resulting in Hemorrhagic Shock: ED Thoracotomy vs. Immediate Trans-Abdominal Vascular Control. A Porcine Model for Evaluating the Management of Non-Compressible Torso Hemorrhage

DTIC Science & Technology

2010-11-08

celiac aortic clamping (n=6), direct vascular control (n=6), and endovascular aortic occlusion n=6). This study presents a large animal model of class...including thoracic aortic clamping, supra- celiac aortic clamping, direct vascular control, and proximal endovascular balloon occlusion. Following vascular...subsequently underwent non-compressible hemorrhage with thoracic aortic clamping (n=6), supra- celiac aortic clamping (n=6), direct vascular control (n=6

Device for remote operation of electrical disconnect

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

Coleman, Jody Rustyn; Bobbitt, III, John Thomas

Provided is a device for remote operation of an electrical disconnect. The device can include a handle clamp configured to be secured to an extending member of the electrical disconnect. The device can further include a case clamp configured to be secured to a rigid portion of the electrical disconnect. The device can further include a cable having an exterior sheath coaxially surrounding an inner cable. The inner cable can be coaxially slidable with respect to the exterior sheath. The inner cable can extend through an opening of the case clamp and be secured to the handle clamp. The devicemore » can further include an actuator configured to coaxially slide the inner cable such that the handle clamp is actuated towards the case clamp.« less

Unitaxial constant velocity microactuator

DOEpatents

McIntyre, Timothy J.

1994-01-01

A uniaxial drive system or microactuator capable of operating in an ultra-high vacuum environment. The mechanism includes a flexible coupling having a bore therethrough, and two clamp/pusher assemblies mounted in axial ends of the coupling. The clamp/pusher assemblies are energized by voltage-operated piezoelectrics therewithin to operatively engage the shaft and coupling causing the shaft to move along its rotational axis through the bore. The microactuator is capable of repeatably positioning to sub-manometer accuracy while affording a scan range in excess of 5 centimeters. Moreover, the microactuator generates smooth, constant velocity motion profiles while producing a drive thrust of greater than 10 pounds. The system is remotely controlled and piezoelectrically driven, hence minimal thermal loading, vibrational excitation, or outgassing is introduced to the operating environment.

Duct Joining System

DOEpatents

Proctor, John P.

2001-02-27

A duct joining system for providing an air-tight seal and mechanical connection for ducts and fittings is disclosed. The duct joining system includes a flexible gasket affixed to a male end of a duct or fitting. The flexible gasket is affixed at an angle relative to normal of the male end of the duct. The female end of the other duct includes a raised bead in which the flexible gasket is seated when the ducts are properly joined. The angled flexible gasket seated in the raised bead forms an air-tight seal as well as fastens or locks the male end to the female end. Alternatively, when a flexible duct is used, a band clamp with a raised bead is clamped over the female end of the flexible duct and over the male end of a fitting to provide an air tight seal and fastened connection.

Duct joining system

DOEpatents

Proctor, John P.; deKieffer, Robert C.

2001-01-01

A duct joining system for providing an air-tight seal and mechanical connection for ducts and fittings is disclosed. The duct joining system includes a flexible gasket affixed to a male end of a duct or fitting. The flexible gasket is affixed at an angle relative to normal of the male end of the duct. The female end of the other duct includes a raised bead in which the flexible gasket is seated when the ducts are properly joined. The angled flexible gasket seated in the raised bead forms an air-tight seal as well as fastens or locks the male end to the female end. Alternatively, when a flexible duct is used, a band clamp with a raised bead is clamped over the female end of the flexible duct and over the male end of a fitting to provide an air tight seal and fastened connection.

MATLAB-based automated patch-clamp system for awake behaving mice

PubMed Central

Siegel, Jennifer J.; Taylor, William; Chitwood, Raymond A.; Johnston, Daniel

2015-01-01

Automation has been an important part of biomedical research for decades, and the use of automated and robotic systems is now standard for such tasks as DNA sequencing, microfluidics, and high-throughput screening. Recently, Kodandaramaiah and colleagues (Nat Methods 9: 585–587, 2012) demonstrated, using anesthetized animals, the feasibility of automating blind patch-clamp recordings in vivo. Blind patch is a good target for automation because it is a complex yet highly stereotyped process that revolves around analysis of a single signal (electrode impedance) and movement along a single axis. Here, we introduce an automated system for blind patch-clamp recordings from awake, head-fixed mice running on a wheel. In its design, we were guided by 3 requirements: easy-to-use and easy-to-modify software; seamless integration of behavioral equipment; and efficient use of time. The resulting system employs equipment that is standard for patch recording rigs, moderately priced, or simple to make. It is written entirely in MATLAB, a programming environment that has an enormous user base in the neuroscience community and many available resources for analysis and instrument control. Using this system, we obtained 19 whole cell patch recordings from neurons in the prefrontal cortex of awake mice, aged 8–9 wk. Successful recordings had series resistances that averaged 52 ± 4 MΩ and required 5.7 ± 0.6 attempts to obtain. These numbers are comparable with those of experienced electrophysiologists working manually, and this system, written in a simple and familiar language, will be useful to many cellular electrophysiologists who wish to study awake behaving mice. PMID:26084901

Characterization of GABAA receptor ligands with automated patch-clamp using human neurons derived from pluripotent stem cells

PubMed Central

Yuan, Nina Y.; Poe, Michael M.; Witzigmann, Christopher; Cook, James M.; Stafford, Douglas; Arnold, Leggy A.

2016-01-01

Introduction Automated patch clamp is a recent but widely used technology to assess pre-clinical drug safety. With the availability of human neurons derived from pluripotent stem cells, this technology can be extended to determine CNS effects of drug candidates, especially those acting on the GABAA receptor. Methods iCell Neurons (Cellular Dynamics International, A Fujifilm Company) were cultured for ten days and analyzed by patch clamp in the presence of agonist GABA or in combination with positive allosteric GABAA receptor modulators. Both efficacy and affinity were determined. In addition, mRNA of GABAA receptor subunits were quantified by qRT-PCR. Results We have shown that iCell Neurons are compatible with the IonFlux microfluidic system of the automated patch clamp instrument. Resistance ranging from 15-25 MΩ was achieved for each trap channel of patch clamped cells in a 96-well plate format. GABA induced a robust change of current with an EC50 of 0.43 μM. Positive GABAA receptor modulators diazepam, HZ166, and CW-04-020 exhibited EC50 values of 0.42 μM, 1.56 μM, and 0.23 μM, respectively. The α2/α3/α5 selective compound HZ166-induced the highest potentiation (efficacy) of 810% of the current induced by 100 nM GABA. Quantification of GABAA receptor mRNA in iCell Neurons revealed high levels of α5 and β3 subunits and low levels of α1, which is similar to the configuration in human neonatal brain. Discussion iCell Neurons represent a new cellular model to characterize GABAergic compounds using automated patch clamp. These cells have excellent representation of cellular GABAA receptor distribution that enable determination of total small molecule efficacy and affinity as measured by cell membrane current change. PMID:27544543

A structural and mechanistic study of π-clamp-mediated cysteine perfluoroarylation.

PubMed

Dai, Peng; Williams, Jonathan K; Zhang, Chi; Welborn, Matthew; Shepherd, James J; Zhu, Tianyu; Van Voorhis, Troy; Hong, Mei; Pentelute, Bradley L

2017-08-11

Natural enzymes use local environments to tune the reactivity of amino acid side chains. In searching for small peptides with similar properties, we discovered a four-residue π-clamp motif (Phe-Cys-Pro-Phe) for regio- and chemoselective arylation of cysteine in ribosomally produced proteins. Here we report mutational, computational, and structural findings directed toward elucidating the molecular factors that drive π-clamp-mediated arylation. We show the significance of a trans conformation prolyl amide bond for the π-clamp reactivity. The π-clamp cysteine arylation reaction enthalpy of activation (ΔH ‡ ) is significantly lower than a non-π-clamp cysteine. Solid-state NMR chemical shifts indicate the prolyl amide bond in the π-clamp motif adopts a 1:1 ratio of the cis and trans conformation, while in the reaction product Pro3 was exclusively in trans. In two structural models of the perfluoroarylated product, distinct interactions at 4.7 Å between Phe1 side chain and perfluoroaryl electrophile moiety are observed. Further, solution 19 F NMR and isothermal titration calorimetry measurements suggest interactions between hydrophobic side chains in a π-clamp mutant and the perfluoroaryl probe. These studies led us to design a π-clamp mutant with an 85-fold rate enhancement. These findings will guide us toward the discovery of small reactive peptides to facilitate abiotic chemistry in water.

Combination Space Station Handrail Clamp and Pointing Device

NASA Technical Reports Server (NTRS)

Hughes, Stephen J. (Inventor)

1999-01-01

A device for attaching an experiment carrier to a space station handrail is provided. The device has two major components, a clamping mechanism for attachment to a space station handrail, and a pointing carrier on which an experiment package can be mounted and oriented. The handrail clamp uses an overcenter mechanism and the carrier mechanism uses an adjustable preload ball and socket for carrier positioning. The handrail clamp uses a stack of disk springs to provide a spring loaded button. This configuration provides consistent clamping force over a range of possible handrail thicknesses. Three load points are incorporated in the clamping mechanism thereby spreading the clamping load onto three separate points on the handrail. A four bar linkage is used to provide for a single actuation lever for all three load points. For additional safety, a secondary lock consisting of a capture plate and push lock keeps the clamp attached to the handrail in the event of main clamp failure. For the carrier positioning mechanism, a ball in a spring loaded socket uses friction to provide locking torque; however. the ball and socket are torque limited so that the ball ran slip under kick loads (125 pounds or greater). A lead screw attached to disk spring stacks is used to provide an adjustable spring force on the socket. A locking knob is attached to the lead screw to allow for hand manipulation of the lead screw.

Cardiovascular transition at birth: a physiological sequence.

PubMed

Hooper, Stuart B; Te Pas, Arjan B; Lang, Justin; van Vonderen, Jeroen J; Roehr, Charles Christoph; Kluckow, Martin; Gill, Andrew W; Wallace, Euan M; Polglase, Graeme R

2015-05-01

The transition to newborn life at birth involves major cardiovascular changes that are triggered by lung aeration. These include a large increase in pulmonary blood flow (PBF), which is required for pulmonary gas exchange and to replace umbilical venous return as the source of preload for the left heart. Clamping the umbilical cord before PBF increases reduces venous return and preload for the left heart and thereby reduces cardiac output. Thus, if ventilation onset is delayed following cord clamping, the infant is at risk of superimposing an ischemic insult, due to low cardiac output, on top of an asphyxic insult. Much debate has centered on the timing of cord clamping at birth, focusing mainly on the potential for a time-dependent placental to infant blood transfusion. This has prompted recommendations for delayed cord clamping for a set time after birth in infants not requiring resuscitation. However, recent evidence indicates that ventilation onset before cord clamping mitigates the adverse cardiovascular consequences caused by immediate cord clamping. This indicates that the timing of cord clamping should be based on the infant's physiology rather than an arbitrary period of time and that delayed cord clamping may be of greatest benefit to apneic infants.

Planar patch clamp for neuronal networks--considerations and future perspectives.

PubMed

Bosca, Alessandro; Martina, Marzia; Py, Christophe

2014-01-01

The patch-clamp technique is generally accepted as the gold standard for studying ion channel activity allowing investigators to either "clamp" membrane voltage and directly measure transmembrane currents through ion channels, or to passively monitor spontaneously occurring intracellular voltage oscillations. However, this resulting high information content comes at a price. The technique is labor-intensive and requires highly trained personnel and expensive equipment. This seriously limits its application as an interrogation tool for drug development. Patch-clamp chips have been developed in the last decade to overcome the tedious manipulations associated with the use of glass pipettes in conventional patch-clamp experiments. In this chapter, we describe some of the main materials and fabrication protocols that have been developed to date for the production of patch-clamp chips. We also present the concept of a patch-clamp chip array providing high resolution patch-clamp recordings from individual cells at multiple sites in a network of communicating neurons. On this chip, the neurons are aligned with the aperture-probes using chemical patterning. In the discussion we review the potential use of this technology for pharmaceutical assays, neuronal physiology and synaptic plasticity studies.

Design and experimental research of a novel inchworm type piezo-driven rotary actuator with the changeable clamping radius.

PubMed

Zhao, Hongwei; Fu, Lu; Ren, Luquan; Huang, Hu; Fan, Zunqiang; Li, Jianping; Qu, Han

2013-01-01

In this paper, a novel piezo-driven rotary actuator with the changeable clamping radius is developed based on the inchworm principle. This actuator mainly utilizes three piezoelectric actuators, a flexible gripper, a clamping block, and a rotor to achieve large stroke rotation with high resolution. The design process of the flexible gripper consisting of the driving unit and the clamping unit is described. Lever-type mechanisms were used to amplify the micro clamping displacements. The amplifying factor and parasitic displacement of the lever-type mechanism in the clamping unit was analyzed theoretically and experimentally. In order to investigate the rotation characteristics of the actuator, a series of experiments was carried out. Experimental results indicate that the actuator can rotate at a speed of 77,488 μrad/s with a driving frequency of 167 Hz. The rotation resolution and maximum load torque of the actuator are 0.25 μrad and 37 N mm, respectively. The gripper is movable along the z direction based on an elevating platform, and the clamping radius can change from 10.6 mm to 25 mm. Experimental results confirm that the actuator can achieve different rotation speeds by changing the clamping radius.

Clinical aspects of incorporating cord clamping into stabilisation of preterm infants.

PubMed

Knol, Ronny; Brouwer, Emma; Vernooij, Alex S N; Klumper, Frans J C M; DeKoninck, Philip; Hooper, Stuart B; Te Pas, Arjan B

2018-04-21

Fetal to neonatal transition is characterised by major pulmonary and haemodynamic changes occurring in a short period of time. In the international neonatal resuscitation guidelines, comprehensive recommendations are available on supporting pulmonary transition and delaying clamping of the cord in preterm infants. Recent experimental studies demonstrated that the pulmonary and haemodynamic transition are intimately linked, could influence each other and that the timing of umbilical cord clamping should be incorporated into the respiratory stabilisation. We reviewed the current knowledge on how to incorporate cord clamping into stabilisation of preterm infants and the physiological-based cord clamping (PBCC) approach, with the infant's transitional status as key determinant of timing of cord clamping. This approach could result in optimal timing of cord clamping and has the potential to reduce major morbidities and mortality in preterm infants. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Sound absorption by clamped poroelastic plates.

PubMed

Aygun, H; Attenborough, K

2008-09-01

Measurements and predictions have been made of the absorption coefficient and the surface acoustic impedance of poroelastic plates clamped in a large impedance tube and separated from the rigid termination by an air gap. The measured and predicted absorption coefficient and surface impedance spectra exhibit low frequency peaks. The peak frequencies observed in the absorption coefficient are close to those predicted and measured in the deflection spectra of the clamped poroelastic plates. The influences of the rigidity of the clamping conditions and the width of the air gap have been investigated. Both influences are found to be important. Increasing the rigidity of clamping reduces the low frequency absorption peaks compared with those measured for simply supported plates or plates in an intermediate clamping condition. Results for a closed cell foam plate and for two open cell foam plates made from recycled materials are presented. For identical clamping conditions and width of air gap, the results for the different materials differ as a consequence mainly of their different elasticity, thickness, and cell structure.

Double arch mirror study. Part 1: Preliminary engineering report

NASA Technical Reports Server (NTRS)

Vukobratovich, D.; Hillman, D.

1983-01-01

In the proposed design, the NASA AMES 20-in double arch mirror is supported by three clamp and flexure assemblies. The mirror clamp consists of a T-shaped Invar-36 member that goes into a similarly shaped socket in the back of the mirror. The mirror socket is made oversize and contacts the clamp only along the conical surface. The clamp is preloaded by a spring washer and pulls the mirror into contact with the flexure. The clamp is then inserted into the mirror socket through a cutout, is rotated 90 deg, and is then pinned in place. Loading conditions considered in socket design are discussed as well as stress in the socket and clamp. Flexure geometry and stress are examined as well as the effects of flexure error and of mirror cell error.

Fabrication and characterization of a piezoelectric energy harvester with clamped-clamped beams

NASA Astrophysics Data System (ADS)

Cui, Yan; Yu, Menglin; Gao, Shiqiao; Kong, Xiangxin; Gu, Wang; Zhang, Ran; Liu, Bowen

2018-05-01

This work presents a piezoelectric energy harvester with clamped-clamped beams, and it is fabricated with MEMS process. When excited by sinusoidal vibration, the energy harvester has a sharp jumping down phenomenon and the measured frequency responses of the clamped-clamped beams structure show a larger bandwidth which is about 56Hz, more efficient than that with cantilever beams. When the exciting acceleration ac is 12m/s2, the energy harvester achieves to a maximum open-circuit voltage of 94mV on one beam. The load voltage is proportional to the load resistance, and it increased with the increase of load resistance. Connected four beams in series, the output power reaches the maximum value of 730 nW and the optimal load is 15KΩ to one beam.

Rigid clamp

DOEpatents

Benavides, G.L.; Burt, J.D.

1994-07-12

The invention relates to a clamp mechanism that can be used to attach or temporarily support objects inside of tubular goods. The clamp mechanism can also be modified so that it grips objects. The clamp has a self-centering feature to accommodate out-of-roundness or other internal defections in tubular objects such as pipe. A plurality of clamping shoes are expanded by a linkage which is preferably powered by a motor to contact the inside of a pipe. The motion can be reversed and jaw elements can be connected to the linkage so as to bring the jaws together to grab an object. 12 figs.

Rigid clamp

DOEpatents

Benavides, Gilbert L.; Burt, Jack D.

1994-01-01

The invention relates to a clamp mechanism that can be used to attach or temporarily support objects inside of tubular goods. The clamp mechanism can also be modified so that it grips objects. The clamp has a self-centering feature to accommodate out-of-roundness or other internal defections in tubular objects such as pipe. A plurality of clamping shoes are expanded by a linkage which is preferably powered by a motor to contact the inside of a pipe. The motion can be reversed and jaw elements can be connected to the linkage so as to bring the jaws together to grab an object.

Advanced motor driven clamped borehole seismic receiver

DOEpatents

Engler, Bruce P.; Sleefe, Gerard E.; Striker, Richard P.

1993-01-01

A borehole seismic tool including a borehole clamp which only moves perpendicular to the borehole. The clamp is driven by an electric motor, via a right angle drive. When used as a seismic receiver, the tool has a three part housing, two of which are hermetically sealed. Accelerometers or geophones are mounted in one hermetically sealed part, the electric meter in the other hermetically sealed part, and the clamp and right angle drive in the third part. Preferably the tool includes cable connectors at both ends. Optionally a shear plate can be added to the clamp to extend the range of the tool.

Radial wedge flange clamp

DOEpatents

Smith, Karl H.

2002-01-01

A radial wedge flange clamp comprising a pair of flanges each comprising a plurality of peripheral flat wedge facets having flat wedge surfaces and opposed and mating flat surfaces attached to or otherwise engaged with two elements to be joined and including a series of generally U-shaped wedge clamps each having flat wedge interior surfaces and engaging one pair of said peripheral flat wedge facets. Each of said generally U-shaped wedge clamps has in its opposing extremities apertures for the tangential insertion of bolts to apply uniform radial force to said wedge clamps when assembled about said wedge segments.

STRUCTURE FOR SUB-ASSEMBLIES OF ELECTRONIC EQUIPMENT

DOEpatents

Bell, P.R.; Harris, C.C.

1959-03-31

Sub-assemblies for electronic systems, particularly a unit which is self- contained and which may be adapted for quick application to and detachment from a chassis or panel, are discussed. The disclosed structure serves the dual purpose of a cover or enclosure for a subassembly comprising a base plate and also acts as a clamp for retaining the base plate in position on a chassis. The clamping action is provided by flexible fingers projecting from the side walls of the cover and extending through grooves in the base plate to engage with the opposite side of the chassis.

Urinary urea nitrogen excretion during the hyperinsulinemic euglycemic clamp in type 1 diabetic patients and healthy subjects.

PubMed

Wohl, P; Krusinová, E; Klementová, M; Wohl, P; Kratochvílová, S; Pelikánová, T

2008-01-01

The hyperinsulinemic euglycemic clamp (HEC) combined with indirect calorimetry (IC) is used for estimation of insulin-stimulated substrate utilization. Calculations are based on urinary urea nitrogen excretion (UE), which is influenced by correct urine collection. The aims of our study were to improve the timing of urine collection during the clamp and to test the effect of insulin on UE in patients with type 1 diabetes (DM1; n=11) and healthy subjects (C; n=11). Urine samples were collected (a) over 24 h divided into 3-h periods and (b) before and during two-step clamp (1 and 10 mIU.kg(-1).min(-1); period 1 and period 2) combined with IC. The UE during the clamp was corrected for changes in urea pool size (UEc). There were no significant differences in 24-h UE between C and DM1 and no circadian variation in UE in either group. During the clamp, serum urea decreased significantly in both groups (p<0.01). Therefore, UEc was significantly lower as compared to UE not adjusted for changes in urea pool size both in C (p<0.001) and DM1 (p<0.001). While UE did not change during the clamp, UEc decreased significantly in both groups (p<0.01). UEc during the clamp was significantly higher in DM1 compared to C both in period 1 (p<0.05) and period 2 (p<0.01). The UE over 24 h and UEc during the clamp were statistically different in both C and DM1. We conclude that urine collection performed during the clamp with UE adjusted for changes in urea pool size is the most suitable technique for measuring substrate utilization during the clamp both in DM1 and C. Urine collections during the clamp cannot be replaced either by 24-h sampling (periods I-VII) or by a single 24-h urine collection. Attenuated insulin-induced decrease in UEc in DM1 implicates the impaired insulin effect on proteolysis.

Efficacy of tranexamic acid plus drain-clamping to reduce blood loss in total knee arthroplasty: A meta-analysis.

PubMed

Zhang, Yan; Zhang, Jun-Wei; Wang, Bao-Hua

2017-06-01

Perioperative blood loss is still an unsolved problem in total knee arthroplasty (TKA). The efficacy of the preoperative use of tranexamic acid (TXA) plus drain-clamping to reduce blood loss in TKA has been debated. This meta-analysis aimed to illustrate the efficacy of TXA plus drain-clamping to reduce blood loss in patients who underwent a TKA. In February 2017, a systematic computer-based search was conducted in PubMed, EMBASE, Web of Science, the Cochrane Database of Systematic Reviews, and Google Scholar. Data from patients prepared for TKA in studies that compared TXA plus drain-clamping versus TXA alone, drain-clamping alone, or controls were retrieved. The primary endpoint was the need for transfusion. The secondary outcomes were total blood loss, blood loss in drainage, the decrease in hemoglobin, and the occurrence of deep venous thrombosis. After testing for publication bias and heterogeneity between studies, data were aggregated for random-effects models when necessary. Ultimately, 5 clinical studies with 618 patients (TXA plus drain-clamping group = 249, control group = 130, TXA-alone group = 60, and drain-clamping group = 179) were included. TXA plus drain-clamping could decrease the need for transfusion, total blood loss, blood loss in drainage, and the decrease in hemoglobin than could the control group, the TXA-alone group, and the drain-clamping group (P < .05). There was no significant difference between the occurrence of deep venous thrombosis between the included groups (P > .05). TXA plus drain-clamping can achieve the maximum effects of hemostasis in patients prepared for primary TKA. Because the number and the quality of the included studies were limited, more high-quality randomized controlled trials are needed to identify the optimal dose of TXA and the clamping hours in patients prepared for TKA.

Efficacy of tranexamic acid plus drain-clamping to reduce blood loss in total knee arthroplasty

PubMed Central

Zhang, Yan; Zhang, Jun-Wei; Wang, Bao-Hua

2017-01-01

Abstract Background: Perioperative blood loss is still an unsolved problem in total knee arthroplasty (TKA). The efficacy of the preoperative use of tranexamic acid (TXA) plus drain-clamping to reduce blood loss in TKA has been debated. This meta-analysis aimed to illustrate the efficacy of TXA plus drain-clamping to reduce blood loss in patients who underwent a TKA. Methods: In February 2017, a systematic computer-based search was conducted in PubMed, EMBASE, Web of Science, the Cochrane Database of Systematic Reviews, and Google Scholar. Data from patients prepared for TKA in studies that compared TXA plus drain-clamping versus TXA alone, drain-clamping alone, or controls were retrieved. The primary endpoint was the need for transfusion. The secondary outcomes were total blood loss, blood loss in drainage, the decrease in hemoglobin, and the occurrence of deep venous thrombosis. After testing for publication bias and heterogeneity between studies, data were aggregated for random-effects models when necessary. Results: Ultimately, 5 clinical studies with 618 patients (TXA plus drain-clamping group = 249, control group = 130, TXA-alone group = 60, and drain-clamping group = 179) were included. TXA plus drain-clamping could decrease the need for transfusion, total blood loss, blood loss in drainage, and the decrease in hemoglobin than could the control group, the TXA-alone group, and the drain-clamping group (P < .05). There was no significant difference between the occurrence of deep venous thrombosis between the included groups (P > .05). Conclusions: TXA plus drain-clamping can achieve the maximum effects of hemostasis in patients prepared for primary TKA. Because the number and the quality of the included studies were limited, more high-quality randomized controlled trials are needed to identify the optimal dose of TXA and the clamping hours in patients prepared for TKA. PMID:28658157

Bipolar square-wave current source for transient electromagnetic systems based on constant shutdown time

NASA Astrophysics Data System (ADS)

Wang, Shilong; Yin, Changchun; Lin, Jun; Yang, Yu; Hu, Xueyan

2016-03-01

Cooperative work of multiple magnetic transmitting sources is a new trend in the development of transient electromagnetic system. The key is the bipolar current waves shutdown, concurrently in the inductive load. In the past, it was difficult to use the constant clamping voltage technique to realize the synchronized shutdown of currents with different peak values. Based on clamping voltage technique, we introduce a new controlling method with constant shutdown time. We use the rising time to control shutdown time and use low voltage power source to control peak current. From the viewpoint of the circuit energy loss, by taking the high-voltage capacitor bypass resistance and the capacitor of the passive snubber circuit into account, we establish the relationship between the rising time and the shutdown time. Since the switch is not ideal, we propose a new method to test the shutdown time by the low voltage, the high voltage and the peak current. Experimental results show that adjustment of the current rising time can precisely control the value of the clamp voltage. When the rising time is fixed, the shutdown time is unchanged. The error for shutdown time deduced from the energy consumption is less than 6%. The new controlling method on current shutdown proposed in this paper can be used in the cooperative work of borehole and ground transmitting system.

Bipolar square-wave current source for transient electromagnetic systems based on constant shutdown time.

PubMed

Wang, Shilong; Yin, Changchun; Lin, Jun; Yang, Yu; Hu, Xueyan

2016-03-01

Cooperative work of multiple magnetic transmitting sources is a new trend in the development of transient electromagnetic system. The key is the bipolar current waves shutdown, concurrently in the inductive load. In the past, it was difficult to use the constant clamping voltage technique to realize the synchronized shutdown of currents with different peak values. Based on clamping voltage technique, we introduce a new controlling method with constant shutdown time. We use the rising time to control shutdown time and use low voltage power source to control peak current. From the viewpoint of the circuit energy loss, by taking the high-voltage capacitor bypass resistance and the capacitor of the passive snubber circuit into account, we establish the relationship between the rising time and the shutdown time. Since the switch is not ideal, we propose a new method to test the shutdown time by the low voltage, the high voltage and the peak current. Experimental results show that adjustment of the current rising time can precisely control the value of the clamp voltage. When the rising time is fixed, the shutdown time is unchanged. The error for shutdown time deduced from the energy consumption is less than 6%. The new controlling method on current shutdown proposed in this paper can be used in the cooperative work of borehole and ground transmitting system.

Quantifying Insulin Sensitivity and Entero-Insular Responsiveness to Hyper- and Hypoglycemia in Ferrets

PubMed Central

Sui, Hongshu; Yi, Yaling; Yao, Jianrong; Liang, Bo; Sun, Xingshen; Hu, Shanming; Uc, Aliye; Nelson, Deborah J.; Ode, Katie Larson; Philipson, Louis H.; Engelhardt, John F.; Norris, Andrew W.

2014-01-01

Ferrets are an important emerging model of cystic fibrosis related diabetes. However, there is little documented experience in the use of advanced techniques to quantify aspects of diabetes pathophysiology in the ferret. Glycemic clamps are the gold standard technique to assess both insulin sensitivity and insulin secretion in humans and animal models of diabetes. We therefore sought to develop techniques for glycemic clamps in ferrets. To assess insulin sensitivity, we performed euglycemic hyperinsulinemic clamps in 5–6 week old ferrets in the anesthetized and conscious states. To assess insulin secretion, we performed hyperglycemic clamps in conscious ferrets. To evaluate responsiveness of ferret islet and entero-insular hormones to low glucose, a portion of the hyperglycemic clamps were followed by a hypoglycemic clamp. The euglycemic hyperinsulinemic clamps demonstrated insulin responsiveness in ferrets similar to that previously observed in humans and rats. The anesthetic isoflurane induced marked insulin resistance, whereas lipid emulsion induced mild insulin resistance. In conscious ferrets, glucose appearance was largely suppressed at 4 mU/kg/min insulin infusion, whereas glucose disposal was progressively increased at 4 and 20 mU/kg/min insulin. Hyperglycemic clamp induced first phase insulin secretion. Hypoglycemia induced a rapid diminishment of insulin, as well as a rise in glucagon and pancreatic polypeptide levels. The incretins GLP-1 and GIP were affected minimally by hyperglycemic and hypoglycemic clamp. These techniques will prove useful in better defining the pathophysiology in ferrets with cystic fibrosis related diabetes. PMID:24594704

MATLAB implementation of a dynamic clamp with bandwidth >125 KHz capable of generating INa at 37°C

PubMed Central

Clausen, Chris; Valiunas, Virginijus; Brink, Peter R.; Cohen, Ira S.

2012-01-01

We describe the construction of a dynamic clamp with bandwidth >125 KHz that utilizes a high performance, yet low cost, standard home/office PC interfaced with a high-speed (16 bit) data acquisition module. High bandwidth is achieved by exploiting recently available software advances (code-generation technology, optimized real-time kernel). Dynamic-clamp programs are constructed using Simulink, a visual programming language. Blocks for computation of membrane currents are written in the high-level matlab language; no programming in C is required. The instrument can be used in single- or dual-cell configurations, with the capability to modify programs while experiments are in progress. We describe an algorithm for computing the fast transient Na+ current (INa) in real time, and test its accuracy and stability using rate constants appropriate for 37°C. We then construct a program capable of supplying three currents to a cell preparation: INa, the hyperpolarizing-activated inward pacemaker current (If), and an inward-rectifier K+ current (IK1). The program corrects for the IR drop due to electrode current flow, and also records all voltages and currents. We tested this program on dual patch-clamped HEK293 cells where the dynamic clamp controls a current-clamp amplifier and a voltage-clamp amplifier controls membrane potential, and current-clamped HEK293 cells where the dynamic clamp produces spontaneous pacing behavior exhibiting Na+ spikes in otherwise passive cells. PMID:23224681

Quantifying insulin sensitivity and entero-insular responsiveness to hyper- and hypoglycemia in ferrets.

PubMed

Sui, Hongshu; Yi, Yaling; Yao, Jianrong; Liang, Bo; Sun, Xingshen; Hu, Shanming; Uc, Aliye; Nelson, Deborah J; Ode, Katie Larson; Philipson, Louis H; Engelhardt, John F; Norris, Andrew W

2014-01-01

Ferrets are an important emerging model of cystic fibrosis related diabetes. However, there is little documented experience in the use of advanced techniques to quantify aspects of diabetes pathophysiology in the ferret. Glycemic clamps are the gold standard technique to assess both insulin sensitivity and insulin secretion in humans and animal models of diabetes. We therefore sought to develop techniques for glycemic clamps in ferrets. To assess insulin sensitivity, we performed euglycemic hyperinsulinemic clamps in 5-6 week old ferrets in the anesthetized and conscious states. To assess insulin secretion, we performed hyperglycemic clamps in conscious ferrets. To evaluate responsiveness of ferret islet and entero-insular hormones to low glucose, a portion of the hyperglycemic clamps were followed by a hypoglycemic clamp. The euglycemic hyperinsulinemic clamps demonstrated insulin responsiveness in ferrets similar to that previously observed in humans and rats. The anesthetic isoflurane induced marked insulin resistance, whereas lipid emulsion induced mild insulin resistance. In conscious ferrets, glucose appearance was largely suppressed at 4 mU/kg/min insulin infusion, whereas glucose disposal was progressively increased at 4 and 20 mU/kg/min insulin. Hyperglycemic clamp induced first phase insulin secretion. Hypoglycemia induced a rapid diminishment of insulin, as well as a rise in glucagon and pancreatic polypeptide levels. The incretins GLP-1 and GIP were affected minimally by hyperglycemic and hypoglycemic clamp. These techniques will prove useful in better defining the pathophysiology in ferrets with cystic fibrosis related diabetes.

Dynamic assembly of Hda and the sliding clamp in the regulation of replication licensing

PubMed Central

Kim, Jin S.; Nanfara, Michael T.; Chodavarapu, Sundari; Jin, Kyeong S.; Babu, Vignesh M. P.; Ghazy, Mohamed A.; Chung, Scisung

2017-01-01

Abstract Regulatory inactivation of DnaA (RIDA) is one of the major regulatory mechanisms of prokaryotic replication licensing. In RIDA, the Hda–sliding clamp complex loaded onto DNA directly interacts with adenosine triphosphate (ATP)-bound DnaA and stimulates the hydrolysis of ATP to inactivate DnaA. A prediction is that the activity of Hda is tightly controlled to ensure that replication initiation occurs only once per cell cycle. Here, we determined the crystal structure of the Hda–β clamp complex. This complex contains two pairs of Hda dimers sandwiched between two β clamp rings to form an octamer that is stabilized by three discrete interfaces. Two separate surfaces of Hda make contact with the β clamp, which is essential for Hda function in RIDA. The third interface between Hda monomers occludes the active site arginine finger, blocking its access to DnaA. Taken together, our structural and mutational analyses of the Hda–β clamp complex indicate that the interaction of the β clamp with Hda controls the ability of Hda to interact with DnaA. In the octameric Hda–β clamp complex, the inability of Hda to interact with DnaA is a novel mechanism that may regulate Hda function. PMID:28168278

78 FR 75512 - Airworthiness Directives; The Boeing Company Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-12

... Systems (ECS) bay area during production, which is a flammable leakage zone. Use of incorrect wire support... support clamps within the left and right Environmental Control Systems (ECS) bay area during production... right Environmental Control Systems (ECS) bay area during production, which is a flammable leakage zone...

Spectral infrared hemispherical reflectance measurements for LDEF tray clamps

NASA Technical Reports Server (NTRS)

Cromwell, B. K.; Shepherd, S. D.; Pender, C. W.; Wood, B. E.

1993-01-01

Infrared hemispherical reflectance measurements that were made on 58 chromic acid anodized tray clamps from LDEF are described. The measurements were made using a hemiellipsoidal mirror reflectometer with interferometer for wavelengths between 2-15 microns. The tray clamps investigated were from locations about the entire spacecraft and provided the opportunity for comparing the effects of atomic oxygen at each location. Results indicate there was essentially no dependence on atomic oxygen fluence for the surfaces studied, but there did appear to be a slight dependence on solar radiation exposure. The reflectances of the front sides of the tray clamps consistently were slightly higher than for the protected rear tray clamp surfaces.

Advanced motor driven clamped borehole seismic receiver

DOEpatents

Engler, B.P.; Sleefe, G.E.; Striker, R.P.

1993-02-23

A borehole seismic tool is described including a borehole clamp which only moves perpendicular to the borehole. The clamp is driven by an electric motor, via a right angle drive. When used as a seismic receiver, the tool has a three part housing, two of which are hermetically sealed. Accelerometers or geophones are mounted in one hermetically sealed part, the electric motor in the other hermetically sealed part, and the clamp and right angle drive in the third part. Preferably the tool includes cable connectors at both ends. Optionally a shear plate can be added to the clamp to extend the range of the tool.

A nitric oxide concentration clamp.

PubMed

Zhelyaskov, V R; Godwin, D W

1999-10-01

We report a new method of generating nitric oxide (NO) that possesses several advantages for experimental use. This method consists of a photolysis chamber where NO is released by illuminating photolabile NO donors with light from a xenon lamp, in conjunction with feedback control. Control of the photolysis light was achieved by selectively gating light projected through a shutter before the light was launched into a light guide that conveyed the light to the photolysis chamber. By gating the light in proportion to a sensor that reported nearly instantaneous concentration from the photolysis chamber, a criterion NO concentration could be achieved, which could be easily adjusted to higher or lower criterion levels. To denote the similarity of this process with the electrophysiological process of voltage clamp, we term this process a concentration "clamp." This development enhances the use of the fiber-optic-based system for NO delivery and should enable the execution of experiments where the in situ concentration of NO is particularly critical, such as in biological preparations. Copyright 1999 Academic Press.

Activities of the Boom and Chassis Group

NASA Technical Reports Server (NTRS)

Dell, Jason Scott; Meeks, Thomas Bayne; Merkel, Kelly; Nelson, Brent; Winchell, Tom

1992-01-01

Group One of the NASA Lunar Enabler Project has designed the primary chassis and boom structures for the lunar vehicle. Both components also feature V-clamps that were adapted to interface connections within the structure. The chassis features a front end, rear end section, middle cross-section, and face plate. The rear section contains an extra compartment for the engine, hydraulic pump, fuel bottles, and oil reservoir necessary for the wheel drives. Each section consists of tubular aluminum 6061-T6. The boom features four degrees of freedom system, where the minimum factor of safety of any part is 1.5 (but, normally much higher). It consists of a tapered upper boom, lower boom, and three elbows that complement the articulation joints. Each section of the boom has been constructed from aluminum 6061-T6. There are four joints and eight V-clamps in the boom assembly. The V-clamps feature support rings that prevent axial rotation. They provide easy adaptability and assembly.

Positivity and Almost Positivity of Biharmonic Green's Functions under Dirichlet Boundary Conditions

NASA Astrophysics Data System (ADS)

Grunau, Hans-Christoph; Robert, Frédéric

2010-03-01

In general, for higher order elliptic equations and boundary value problems like the biharmonic equation and the linear clamped plate boundary value problem, neither a maximum principle nor a comparison principle or—equivalently—a positivity preserving property is available. The problem is rather involved since the clamped boundary conditions prevent the boundary value problem from being reasonably written as a system of second order boundary value problems. It is shown that, on the other hand, for bounded smooth domains {Ω subsetmathbb{R}^n} , the negative part of the corresponding Green’s function is “small” when compared with its singular positive part, provided {n≥q 3} . Moreover, the biharmonic Green’s function in balls {Bsubsetmathbb{R}^n} under Dirichlet (that is, clamped) boundary conditions is known explicitly and is positive. It has been known for some time that positivity is preserved under small regular perturbations of the domain, if n = 2. In the present paper, such a stability result is proved for {n≥q 3}.

Friction in Forming of UD Composites

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

Sachs, U.; Haanappel, S. P.; Akkerman, R.

2011-05-04

Inter-ply and tool/ply friction play a dominant role in hot stamp forming of UD fiber-reinforced thermoplastic laminates. This research treats friction measurements of a PEEK-AS4 composite system. To this end, an in-house developed friction tester is utilized to pull a laminate through two heat controlled clamping platens. The friction coefficient is determined by relating the clamp force to the pull force. The geometry of the gap between the clamping platens is monitored with micrometer accuracy. A first approach to describe the relation between the geometry and frictional behavior is undertaken by applying a standard thin-film theory for hydrodynamic lubrication. Experimentalmore » measurements showed that the thin-film theory does not entirely cover the underlying physics. Thus a second model is utilized, which employs a Leonov-model to describe the shear deformation of the matrix material, while its viscosity is described with a multi-mode Maxwell model. The combination of both models shows the potential to capture the complete frictional behavior.« less

Automated navigation of a glass micropipette on a high-density microelectrode array.

PubMed

Jing Lin; Obien, Marie Engelene J; Hierlemann, Andreas; Frey, Urs

2015-08-01

High-density microelectrode arrays (HDMEAs) provide the capability to monitor the extracellular electric potential of multiple neurons at subcellular resolution over extended periods of time. In contrast, patch clamp allows for intracellular, sub-threshold recordings from a single patched neuron for very limited time on the order of an hour. Therefore, it will be beneficial to combine HDMEA and patch clamp for simultaneous intra- and extracellular recording of neuronal activity. Previously, it has been shown that the HDMEA can be used to localize and steer a glass micropipette towards a target location without using an optical microscope [1]. Here, we present an automated system, implemented in LabVIEW, which automatically locates and moves the glass micropipette towards a user-defined target. The presented system constitutes a first step towards developing an automated system to navigate a pipette to patch a neuron in vitro.

Rupture disc

DOEpatents

Newton, Robert G.

1977-01-01

The intermediate heat transport system for a sodium-cooled fast breeder reactor includes a device for rapidly draining the sodium therefrom should a sodium-water reaction occur within the system. This device includes a rupturable member in a drain line in the system and means for cutting a large opening therein and for positively removing the sheared-out portion from the opening cut in the rupturable member. According to the preferred embodiment of the invention the rupturable member includes a solid head seated in the end of the drain line having a rim extending peripherally therearound, the rim being clamped against the end of the drain line by a clamp ring having an interior shearing edge, the bottom of the rupturable member being convex and extending into the drain line. Means are provided to draw the rupturable member away from the drain line against the shearing edge to clear the drain line for outflow of sodium therethrough.

Combinatorial materials research applied to the development of new surface coatings VII: An automated system for adhesion testing

NASA Astrophysics Data System (ADS)

Chisholm, Bret J.; Webster, Dean C.; Bennett, James C.; Berry, Missy; Christianson, David; Kim, Jongsoo; Mayo, Bret; Gubbins, Nathan

2007-07-01

An automated, high-throughput adhesion workflow that enables pseudobarnacle adhesion and coating/substrate adhesion to be measured on coating patches arranged in an array format on 4×8in.2 panels was developed. The adhesion workflow consists of the following process steps: (1) application of an adhesive to the coating array; (2) insertion of panels into a clamping device; (3) insertion of aluminum studs into the clamping device and onto coating surfaces, aligned with the adhesive; (4) curing of the adhesive; and (5) automated removal of the aluminum studs. Validation experiments comparing data generated using the automated, high-throughput workflow to data obtained using conventional, manual methods showed that the automated system allows for accurate ranking of relative coating adhesion performance.

Progress Toward a Bulk Micromachined Tunneling Tip Microaccelerometer

NASA Technical Reports Server (NTRS)

Frank T. Hartley, Ben Dolgen, Paul M. Zavracky

1995-01-01

Ultrasensitive accelerometers are needed for microgravity measurement of orbital drag and active isolation systems. We have designed an accelerometer capable of measuring accelerations of the order of 10(i) g. A tunneling tip sensor can be used as a position sensor with a potential performance advantage of two orders of magnitude over capacitive sensors. In this paper, we disclose our progress in the fabrication and measurement of a bulk microaccelerometer which employs a tunneling tip. Fully assembled accelerometers consisting of four separate die have been fabricated. The device employs a unique folded spring system with a low spring constant. To protect the tunneling tip, we have employed electrostatic clamping. Stiction has not been observed, but the required clamping voltage is greater than expected. We have developed a simple model to analyze our results.

Sperm Patch-Clamp

PubMed Central

Lishko, Polina; Clapham, David E.; Navarro, Betsy; Kirichok, Yuriy

2014-01-01

Sperm intracellular pH and calcium concentration ([Ca2+]i) are two central factors that control sperm activity within the female reproductive tract. As such, the ion channels of the sperm plasma membrane that alter intracellular sperm [Ca2+] and pH play important roles in sperm physiology and the process of fertilization. Indeed, sperm ion channels regulate sperm motility, control sperm chemotaxis toward the egg in some species, and may trigger the acrosome reaction. Until recently, our understanding of these important molecules was rudimentary due to the inability to patch-clamp spermatozoa and directly record the activity of these ion channels under voltage clamp. Recently, we overcame this technical barrier and developed a method for reproducible application of the patch-clamp technique to mouse and human spermatozoa. This chapter covers important aspects of application of the patch-clamp technique to spermatozoa, such as selection of the electrophysiological equipment, isolation of spermatozoa for patch-clamp experiments, formation of the gigaohm seal with spermatozoa, and transition into the whole-cell mode of recording. We also discuss potential pitfalls in application of the patch-clamp technique to flagellar ion channels. PMID:23522465

Comparison of Cell Expression Formats for the Characterization of GABAA Channels Using a Microfluidic Patch Clamp System

PubMed Central

Chen, Qin; Yim, Peter D.; Yuan, Nina; Johnson, Juliette; Cook, James M.; Smith, Steve; Ionescu-Zanetti, Cristian; Wang, Zhi-Jian; Arnold, Leggy A.

2012-01-01

Abstract Ensemble recording and microfluidic perfusion are recently introduced techniques aimed at removing the laborious nature and low recording success rates of manual patch clamp. Here, we present assay characteristics for these features integrated into one automated electrophysiology platform as applied to the study of GABAA channels. A variety of cell types and methods of GABAA channel expression were successfully studied (defined as IGABA>500 pA), including stably transfected human embryonic kidney (HEK) cells expressing α1β3γ2 GABAA channels, frozen ready-to-assay (RTA) HEK cells expressing α1β3γ2 or α3β3γ2 GABAA channels, transiently transfected HEK293T cells expressing α1β3γ2 GABAA channels, and immortalized cultures of human airway smooth muscle cells endogenously expressing GABAA channels. Current measurements were successfully studied in multiple cell types with multiple modes of channel expression in response to several classic GABAA channel agonists, antagonists, and allosteric modulators. We obtained success rates above 95% for transiently or stably transfected HEK cells and frozen RTA HEK cells expressing GABAA channels. Tissue-derived immortalized cultures of airway smooth muscle cells exhibited a slightly lower recording success rate of 75% using automated patch, which was much higher than the 5% success rate using manual patch clamp technique by the same research group. Responses to agonists, antagonists, and allosteric modulators compared well to previously reported manual patch results. The data demonstrate that both the biophysics and pharmacologic characterization of GABAA channels in a wide variety of cell formats can be performed using this automated patch clamp system. PMID:22574655

Obstetricians' attitudes, subjective norms, perceived controls, and intentions on antibiotic prophylaxis in caesarean section.

PubMed

Liabsuetrakul, Tippawan; Chongsuvivatwong, Virasakdi; Lumbiganon, Pisake; Lindmark, Gunilla

2003-11-01

Over 10% of current births in all countries of the world are delivered by caesarean section. Single-dose ampicillin or cefazolin administered after cord clamping has been proven to be effective for the prevention of post-caesarean infections as indicated in many randomised trials and reviews in the Cochrane Library. This study aimed to determine three determinants of behavioural intention using the theory of planned behaviour: attitudes, subjective norms, and perceived controls. Intentions were examined for five aspects of the use of antibiotic prophylaxis, namely whether or not antibiotics were used, used in all caesarean sections, after rather than before cord clamping, whether ampicillin/cefazolin or broader-spectrum antibiotics were used, and whether single or multiple doses were given. Fifty obstetricians selected from university, regional, and general hospitals in southern Thailand, were surveyed using a questionnaire and in-depth interview. Their intentions to use a single dose and to use in all cases were low, and this was related to negative attitudes and reference groups who did not approve of the single dose. The negative attitude was based on scepticism concerning the applicability of well-equipped trials from the developed world and fear of consequences of post-caesarean infections. Norms carried over from residency training had more long-term influence in their practice than newer information from books or journals. Perceived external controls on their practice were less predictive of intentions. Intentions were only partly predictive of behaviour. Changing attitudes, introducing evidence-based information into residency training and strengthening control systems in the hospital are essential to improve intentions.

A clamping force measurement system for monitoring the condition of bolted joints on railway track joints and points

NASA Astrophysics Data System (ADS)

Tesfa, B.; Horler, G.; Thobiani, F. Al; Gu, F.; Ball, A. D.

2012-05-01

Many industrial structures associated with railway infrastructures rely on a large number of bolted joint connections to ensure safe and reliable operation of the track and trackside furniture. Significant sums of money are spent annually to repair the damage caused by bolt failures and to maintain the integrity of bolted structures. In the UK, Network Rail (the organization responsible for rail network maintenance and safety) conducts corrective and preventive maintenance manually on 26,000 sets of points (each having approximately 30 bolted joints per set), in order to ensure operational success and safety for the travelling public. Such manual maintenance is costly, disruptive, unreliable and prone to human error. The aim of this work is to provide a means of automatically measuring the clamping force of each individual bolted joint, by means of an instrumented washer. This paper describes the development of a sensor means to be used in the washer, which satisfies the following criteria. Sense changes in the clamping force of the joint and report this fact. Provide compatibility with the large dynamic range of clamping force. Satisfy the limitations in terms of physical size. Provide the means to electronically interface with the washer. Provide a means of powering the washer in situ. Provide a solution at an acceptable cost. Specifically the paper focuses on requirements 1, 2 and 3 and presents the results that support further development of the proposed design and the realization of a pre-prototype system. In the paper, various options for the force sensing element (strain gage, capacitor, piezo-resistive) have been compared, using design optimization techniques. As a result of the evaluation, piezo-resistive sensors in concert with a proprietary force attenuation method, have been found to offer the best performance and cost trade-off The performance of the novel clamping force sensor has been evaluated experimentally and the results show that a smart washer can be developed to monitor the condition of bolted joints as found on railway track and points.

Localized, stepwise template growth of functional nanowires from an amino acid-supported framework in a microfluidic chip.

PubMed

Puigmartí-Luis, Josep; Rubio-Martínez, Marta; Imaz, Inhar; Cvetković, Benjamin Z; Abad, Llibertat; Pérez Del Pino, Angel; Maspoch, Daniel; Amabilino, David B

2014-01-28

A spatially controlled synthesis of nanowire bundles of the functional crystalline coordination polymer (CP) Ag(I)TCNQ (tetracyanoquinodimethane) from previously fabricated and trapped monovalent silver CP (Ag(I)Cys (cysteine)) using a room-temperature microfluidic-assisted templated growth method is demonstrated. The incorporation of microengineered pneumatic clamps in a two-layer polydimethylsiloxane-based (PDMS) microfluidic platform was used. Apart from guiding the formation of the Ag(I)Cys coordination polymer, this microfluidic approach enables a local trapping of the in situ synthesized structures with a simple pneumatic clamp actuation. This method not only enables continuous and multiple chemical events to be conducted upon the trapped structures, but the excellent fluid handling ensures a precise chemical activation of the amino acid-supported framework in a position controlled by interface and clamp location that leads to a site-specific growth of Ag(I)TCNQ nanowire bundles. The synthesis is conducted stepwise starting with Ag(I)Cys CPs, going through silver metal, and back to a functional CP (Ag(I)TCNQ); that is, a novel microfluidic controlled ligand exchange (CP → NP → CP) is presented. Additionally, the pneumatic clamps can be employed further to integrate the conductive Ag(I)TCNQ nanowire bundles onto electrode arrays located on a surface, hence facilitating the construction of the final functional interfaced systems from solution specifically with no need for postassembly manipulation. This localized self-supported growth of functional matter from an amino acid-based CP shows how sequential localized chemistry in a fluid cell can be used to integrate molecular systems onto device platforms using a chip incorporating microengineered pneumatic tools. The control of clamp pressure and in parallel the variation of relative flow rates of source solutions permit deposition of materials at different locations on a chip that could be useful for device array preparation. The in situ reaction and washing procedures make this approach a powerful one for the fabrication of multicomponent complex nanomaterials using a soft bottom-up approach.

RNA polymerase pausing and nascent RNA structure formation are linked through clamp domain movement

PubMed Central

Hein, Pyae P.; Kolb, Kellie E.; Windgassen, Tricia; Bellecourt, Michael J.; Darst, Seth A.; Mooney, Rachel A.; Landick, Robert

2014-01-01

The rates of RNA synthesis and nascent RNA folding into biologically active structures are linked via pausing by RNA polymerase (RNAP). Structures that form within the RNA exit channel can increase pausing by interacting with bacterial RNAP or decrease pausing by preventing backtracking. Conversely, pausing is required for proper folding of some RNAs. Opening of the RNAP clamp domain is proposed to mediate some effects of nascent RNA structures. However, the connections among RNA structure formation, clamp movement, and catalytic activity remain uncertain. We assayed exit-channel structure formation in Escherichia coli RNAP together with disulfide crosslinks that favor closed or open clamp conformations and found that clamp position directly influences RNA structure formation and catalytic activity. We report that exit-channel RNA structures slow pause escape by favoring clamp opening and through interactions with the flap that slow translocation. PMID:25108353

Automated multi-slice extracellular and patch-clamp experiments using the WinLTP data acquisition system with automated perfusion control

PubMed Central

Anderson, William W.; Fitzjohn, Stephen M.; Collingridge, Graham L.

2012-01-01

WinLTP is a data acquisition program for studying long-term potentiation (LTP) and other aspects of synaptic function. Earlier versions of WinLTP (J. Neurosci. Methods, 162:346–356, 2007) provided automated electrical stimulation and data acquisition capable of running nearly an entire synaptic plasticity experiment, with the primary exception that perfusion solutions had to be changed manually. This automated stimulation and acquisition was done by using ‘Sweep’, ‘Loop’ and ‘Delay’ events to build scripts using the ‘Protocol Builder’. However, this did not allow automatic changing of many solutions while running multiple slice experiments, or solution changing when this had to be performed rapidly and with accurate timing during patch-clamp experiments. We report here the addition of automated perfusion control to WinLTP. First, perfusion change between sweeps is enabled by adding the ‘Perfuse’ event to Protocol Builder scripting and is used in slice experiments. Second, fast perfusion changes during as well as between sweeps is enabled by using the Perfuse event in the protocol scripts to control changes between sweeps, and also by changing digital or analog output during a sweep and is used for single cell single-line perfusion patch-clamp experiments. The addition of stepper control of tube placement allows dual- or triple-line perfusion patch-clamp experiments for up to 48 solutions. The ability to automate perfusion changes and fully integrate them with the already automated stimulation and data acquisition goes a long way toward complete automation of multi-slice extracellularly recorded and single cell patch-clamp experiments. PMID:22524994

From Understanding Cellular Function to Novel Drug Discovery: The Role of Planar Patch-Clamp Array Chip Technology

PubMed Central

Py, Christophe; Martina, Marzia; Diaz-Quijada, Gerardo A.; Luk, Collin C.; Martinez, Dolores; Denhoff, Mike W.; Charrier, Anne; Comas, Tanya; Monette, Robert; Krantis, Anthony; Syed, Naweed I.; Mealing, Geoffrey A. R.

2011-01-01

All excitable cell functions rely upon ion channels that are embedded in their plasma membrane. Perturbations of ion channel structure or function result in pathologies ranging from cardiac dysfunction to neurodegenerative disorders. Consequently, to understand the functions of excitable cells and to remedy their pathophysiology, it is important to understand the ion channel functions under various experimental conditions – including exposure to novel drug targets. Glass pipette patch-clamp is the state of the art technique to monitor the intrinsic and synaptic properties of neurons. However, this technique is labor intensive and has low data throughput. Planar patch-clamp chips, integrated into automated systems, offer high throughputs but are limited to isolated cells from suspensions, thus limiting their use in modeling physiological function. These chips are therefore not most suitable for studies involving neuronal communication. Multielectrode arrays (MEAs), in contrast, have the ability to monitor network activity by measuring local field potentials from multiple extracellular sites, but specific ion channel activity is challenging to extract from these multiplexed signals. Here we describe a novel planar patch-clamp chip technology that enables the simultaneous high-resolution electrophysiological interrogation of individual neurons at multiple sites in synaptically connected neuronal networks, thereby combining the advantages of MEA and patch-clamp techniques. Each neuron can be probed through an aperture that connects to a dedicated subterranean microfluidic channel. Neurons growing in networks are aligned to the apertures by physisorbed or chemisorbed chemical cues. In this review, we describe the design and fabrication process of these chips, approaches to chemical patterning for cell placement, and present physiological data from cultured neuronal cells. PMID:22007170

From understanding cellular function to novel drug discovery: the role of planar patch-clamp array chip technology.

PubMed

Py, Christophe; Martina, Marzia; Diaz-Quijada, Gerardo A; Luk, Collin C; Martinez, Dolores; Denhoff, Mike W; Charrier, Anne; Comas, Tanya; Monette, Robert; Krantis, Anthony; Syed, Naweed I; Mealing, Geoffrey A R

2011-01-01

All excitable cell functions rely upon ion channels that are embedded in their plasma membrane. Perturbations of ion channel structure or function result in pathologies ranging from cardiac dysfunction to neurodegenerative disorders. Consequently, to understand the functions of excitable cells and to remedy their pathophysiology, it is important to understand the ion channel functions under various experimental conditions - including exposure to novel drug targets. Glass pipette patch-clamp is the state of the art technique to monitor the intrinsic and synaptic properties of neurons. However, this technique is labor intensive and has low data throughput. Planar patch-clamp chips, integrated into automated systems, offer high throughputs but are limited to isolated cells from suspensions, thus limiting their use in modeling physiological function. These chips are therefore not most suitable for studies involving neuronal communication. Multielectrode arrays (MEAs), in contrast, have the ability to monitor network activity by measuring local field potentials from multiple extracellular sites, but specific ion channel activity is challenging to extract from these multiplexed signals. Here we describe a novel planar patch-clamp chip technology that enables the simultaneous high-resolution electrophysiological interrogation of individual neurons at multiple sites in synaptically connected neuronal networks, thereby combining the advantages of MEA and patch-clamp techniques. Each neuron can be probed through an aperture that connects to a dedicated subterranean microfluidic channel. Neurons growing in networks are aligned to the apertures by physisorbed or chemisorbed chemical cues. In this review, we describe the design and fabrication process of these chips, approaches to chemical patterning for cell placement, and present physiological data from cultured neuronal cells.

Lotus birth, a holistic approach on physiological cord clamping.

PubMed

Zinsser, Laura A

2018-04-01

The positive effects of delayed cord clamping (DCC) has been extensively researched. DCC means: waiting at least one minute after birth before clamping and cutting the cord or till the pulsation has stopped. With physiological clamping and cutting (PCC) the clamping and cutting can happen at the earliest after the pulsation has stopped. With a Lotus birth, no clamping and cutting of the cord is done. A woman called Clair Lotus Day imitated the holistic approach of PCC from an anthropoid ape in 1974. The chimpanzee did not separate the placenta from the newborn. The aim of this case report is to discuss and learn a different approach in the third stage of labour. Three cases of Lotus birth by human beings were observed. All three women gave birth in an out-of-hospital setting and had ambulant postnatal care. The placenta was washed, salted and herbs were put on 2-3h post partum. The placenta was wrapped in something that absorbs the moisture. The salting was repeated with a degreasing frequency depending on moistness of the placenta. On life day six all three Lotus babies experiences a natural separation of the cord. All three Lotus birth cases were unproblematic, no special incidence occurred. One should differentiate between early cord clamping (ECC), delayed cord clamping (DCC) and physiological cord clamping (PCC). Lotus birth might lead to an optimisation of the bonding and attachment. Research is needed in the areas of both PCC and Lotus birth. Copyright © 2017 Australian College of Midwives. Published by Elsevier Ltd. All rights reserved.

Molecular mechanism of DNA replication-coupled inactivation of the initiator protein in Escherichia coli: interaction of DnaA with the sliding clamp-loaded DNA and the sliding clamp-Hda complex.

PubMed

Su'etsugu, Masayuki; Takata, Makoto; Kubota, Toshio; Matsuda, Yusaku; Katayama, Tsutomu

2004-06-01

In Escherichia coli, the ATP-DnaA protein initiates chromosomal replication. After the DNA polymerase III holoenzyme is loaded on to DNA, DnaA-bound ATP is hydrolysed in a manner depending on Hda protein and the DNA-loaded form of the DNA polymerase III sliding clamp subunit, which yields ADP-DnaA, an inactivated form for initiation. This regulatory DnaA-inactivation represses extra initiation events. In this study, in vitro replication intermediates and structured DNA mimicking replicational intermediates were first used to identify structural prerequisites in the process of DnaA-ATP hydrolysis. Unlike duplex DNA loaded with sliding clamps, primer RNA-DNA heteroduplexes loaded with clamps were not associated with DnaA-ATP hydrolysis, and duplex DNA provided in trans did not rescue this defect. At least 40-bp duplex DNA is competent for the DnaA-ATP hydrolysis when a single clamp was loaded. The DnaA-ATP hydrolysis was inhibited when ATP-DnaA was tightly bound to a DnaA box-bearing oligonucleotide. These results imply that the DnaA-ATP hydrolysis involves the direct interaction of ATP-DnaA with duplex DNA flanking the sliding clamp. Furthermore, Hda protein formed a stable complex with the sliding clamp. Based on these, we suggest a mechanical basis in the DnaA-inactivation that ATP-DnaA interacts with the Hda-clamp complex with the aid of DNA binding. Copyright Blackwell Publishing Limited

Mechanical coupling for a rotor shaft assembly of dissimilar materials

DOEpatents

Shi, Jun [Glastonbury, CT; Bombara, David [New Hartford, CT; Green, Kevin E [Broad Brook, CT; Bird, Connic [Rocky Hill, CT; Holowczak, John [South Windsor, CT

2009-05-05

A mechanical coupling for coupling a ceramic disc member to a metallic shaft includes a first wedge clamp and a second wedge clamp. A fastener engages a threaded end of a tie-bolt to sandwich the ceramic disc between the wedge clamps. An axial spring is positioned between the fastener and the second wedge clamp to apply an axial preload along the longitudinal axis. Another coupling utilizes a rotor shaft end of a metallic rotor shaft as one wedge clamp. Still another coupling includes a solid ceramic rotor disc with a multiple of tie-bolts radially displaced from the longitudinal axis to exert the preload on the solid ceramic rotor disc.

Laser beam guard clamps

DOEpatents

Dickson, Richard K.

2010-09-07

A quick insert and release laser beam guard panel clamping apparatus having a base plate mountable on an optical table, a first jaw affixed to the base plate, and a spring-loaded second jaw slidably carried by the base plate to exert a clamping force. The first and second jaws each having a face acutely angled relative to the other face to form a V-shaped, open channel mouth, which enables wedge-action jaw separation by and subsequent clamping of a laser beam guard panel inserted through the open channel mouth. Preferably, the clamping apparatus also includes a support structure having an open slot aperture which is positioned over and parallel with the open channel mouth.

Effects of introducing a single charged residue into the phenylalanine clamp of multimeric anthrax protective antigen.

PubMed

Janowiak, Blythe E; Fischer, Audrey; Collier, R John

2010-03-12

Multimeric pores formed in the endosomal membrane by the Protective Antigen moiety of anthrax toxin translocate the enzymatic moieties of the toxin to the cytosolic compartment of mammalian cells. There is evidence that the side chains of the Phe(427) residues come into close proximity with one another in the lumen of the pore and form a structure, termed the Phe clamp, that catalyzes the translocation process. In this report we describe the effects of replacing Phe(427) in a single subunit of the predominantly heptameric pore with a basic or an acidic amino acid. Incorporating any charged residue at this position inhibited cytotoxicity >or=1,000-fold in our standard assay and caused strong inhibition of translocation in a planar phospholipid bilayer system. His and Glu were the most strongly inhibitory residues, ablating both cytotoxicity and translocation. Basic residues at position 427 prevented the Phe clamp from interacting with a translocation substrate to form a seal against the passage of ions and accelerated dissociation of the substrate from the pore. Acidic residues, in contrast, allowed the seal to form and the substrate to remain firmly bound, but blocked its passage, perhaps via electrostatic interactions with the positively charged N-terminal segment. Our findings are discussed in relation to the role of the Phe clamp in a Brownian ratchet model of translocation.

Self-aligning fixture used in lathe chuck jaw refacing

NASA Technical Reports Server (NTRS)

Linn, C. C.

1965-01-01

Self-aligning tool positions and rigidly holds lathe chuck jaws for refacing and truing of the clamping surface. The jaws clamp the fixture in the manner of clamping a workpiece. The fixture can be modified to accommodate four-jawed checks.

Analysis of failed and nickel-coated 3093 beam clamp components at the East Tennessee Technology Park (ETTP).

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

Singh, D.; Pappacena, K.; Gaviria, J.

2010-10-11

The U.S. Department of Energy and its contractor, Bechtel Jacobs Company (BJC), are undertaking a major effort to clean up the former gaseous diffusion facility (K-25) located in Oak Ridge, TN. The decontamination and decommissioning activities require systematic removal of contaminated equipment and machinery followed by demolition of the buildings. As part of the cleanup activities, a beam clamp, used for horizontal life lines (HLLs) for fall protection, was discovered to be fractured during routine inspection. The beam clamp (yoke and D-ring) was a component in the HLL system purchased from Reliance Industries LLC. Specifically, the U-shaped stainless steel yokemore » of the beam clamp failed in a brittle mode at under less than 10% of the rated design capacity of 14,500 lb. The beam clamp had been in service for approximately 16 months. Bechtel Jacobs approached Argonne National Laboratory to assist in identifying the root cause of the failure of the beam clamp. The objectives of this study were to (1) review the prior reports and documents on the subject, (2) understand the possible failure mechanism(s) that resulted in the failed beam clamp components, (3) recommend approaches to mitigate the failure mechanism(s), and (4) evaluate the modified beam clamp assemblies. Energy dispersive x-ray analysis and chemical analysis of the corrosion products on the failed yoke and white residue on an in-service yoke indicated the presence of zinc, sulfur, and calcium. Analysis of rainwater in the complex, as conducted by BJC, indicated the presence of sulfur and calcium. It was concluded that, as a result of galvanic corrosion, zinc from the galvanized components of the beam clamp assembly (D-ring) migrated to the corroded region in the presence of the rainwater. Under mechanical stress, the corrosion process would have accelerated, resulting in the catastrophic failure of the yoke. As suggested by Bechtel Jacobs personnel, hydrogen embrittlement as a consequence of corrosion was also explored as a failure mechanism. Corroded and failed yoke samples had hydrogen concentrations of 20-60 ppm. However, the hydrogen content reduced to 4-11 ppm (similar to baseline as-received yoke samples) when the corrosion products were polished off. The hydrogen content in the scraped off corrosion product powders was >7000 ppm. These results indicate that hydrogen is primarily present in the corrosion products and not in the underlying steel. Rockwell hardness values on the corroded yoke and D-rings were R{sub c} {approx} 41-46. It was recommended to the beam clamp manufacturer that the beam clamp components be annealed to reduce the hardness values so that they are less susceptible to brittle failure. Upon annealing, hardness values of the beam clamp components reduced to R{sub c} {approx} 25. Several strategies were recommended and put in place to mitigate failure of the beam clamp components: (a) maintain hardness levels of both yokes and D-rings at R{sub c} < 35, (b) coat the yoke and D-rings with a dual coating of nickel (with 10% phosphorus) to delay corrosion and aluminum to prevent galvanic corrosion since it is more anodic to zinc, and (c) optimize coating thicknesses for nickel and aluminum while maintaining the physical integrity of the coatings. Evaluation of the Al- and Ni-coated yoke and D-ring specimens indicated they appear to have met the recommendations. Average hardness values of the dual-coated yokes were R{sub c} {approx} 25-35. Hardness values of dual-coated D-ring were R{sub c} {approx} 32. Measured average coating thicknesses for the aluminum and nickel coatings for yoke samples were 22 {micro}m (0.9 mils) and 80 {micro}m (3 mils), respectively. The D-rings also showed similar coating thicknesses. Microscopic examination showed that the aluminum coating was well bonded to the underlying nickel coating. Some observed damage was believed to be an artifact of the cutting-and-polishing steps during sample preparation for microscopy.« less

Storage containers for radioactive material

DOEpatents

Groh, E.F.; Cassidy, D.A.; Dates, L.R.

1980-07-31

A radioactive material storage system is claimed for use in the laboratory having a flat base plate with a groove in one surface thereof and a hollow pedestal extending perpendicularly away from the other surface thereof, a sealing gasket in the groove, a cover having a filter therein and an outwardly extending flange which fits over the plate, the groove and the gasket, and a clamp for maintaining the cover and the plate sealed together. The plate and the cover and the clamp cooperate to provide a storage area for radioactive material readily accessible for use or inventory. Wall mounts are provided to prevent accidental formation of critical masses during storage.

The optimal protocol to reduce blood loss and blood transfusion after unilateral total knee replacement: Low-dose IA-TXA plus 30-min drain clamping versus drainage clamping for the first 3 h without IA-TXA.

PubMed

Park, Joo Hyun; Choi, Sung Wook; Shin, Eun Ho; Park, Myung Hoon; Kim, Myung Ku

2017-01-01

Although intraarticular tranexamic acid (IA-TXA) administration or drainage clamping are popular methods used to reduce blood loss after total knee replacement (TKR), the protocol remains controversial. We aimed (1) to establish new protocols through investigating whether two methods, that is, low-dose (500 mg) IA-TXA plus 30-min drain clamping and drainage clamping for the first 3 h without IA-TXA, can reduce blood loss and blood transfusion after unilateral TKR and (2) to make recommendations related to clinical application. This study, conducted from September 2014 to June 2016 related to enrolled 95 patients with primary osteoarthritis who were to have a unilateral cemented TKR, was nonrandomized and retrospective. In group A, the drain was released following tourniquet deflation. In group B, 500-mg TXA was injected into the knee joint via a drain tube after fascia closure and the drain was clamped for the first 30 min to prevent leakage. In group C, the drain was clamped for the first 3-h postoperation. Demographic characteristics and clinical data were collected, including the levels of hematocrit (Hct), the total blood loss (TBL), drained blood volume (BV), the amount of blood transfused, and any complications that developed. We found a significantly lower postoperative TBL, drained BV, decreasing Hct level, and less transfused BV in the IA-TXA injection group (group B) and the 3-h drainage clamping group (group C) compared to the conventional negative drainage group (group A; p < 0.001). There was no significant difference between groups B and C ( p = 0.99). The drainage clamping method can be safer than IA-TXA administration in patients with risk factor of venous thromboembolic complication. Furthermore, the IA-TXA administration can be more optimal than drainage clamping in patients with high bleeding tendency or lateral retinacular release during TKR, who would be concerned about postoperative wound complication.

Temporary clamping of external carotid artery in convexity, parasagittal and temporal base meningioma.

PubMed

Yadav, Yad Ram; Parihar, Vijay; Agarwal, Moneet; Bhatele, Pushp Raj

2012-01-01

The management of intraoperative bleeding during removal of a large hyper vascular meningioma is crucial for safe and efficient surgery. Preoperative embolization of meningioma is the best way to reduce vascularity of meningiomas but this technique is not readily available, costly and has its own limitations. The study is aimed to evaluate the use of temporary clamping of external carotid artery to reduce blood loss and operating time during excision of large convexity, parasagittal or temporal base meningiomas. A prospective study of 115 consecutively operated meningiomas of size 5 cms or more were operated from January 2002 to December2010. Temporary clamping of external carotid artery was done in 61 while 51 cases were managed without clamping. There was significant reduction of blood loss, operative time and blood transfusion given in the temporary clipping group compared to non clipping group. There was stitch abscess in two patients each in clamping, and non clamping group. There was no scalp necrosis or mortality in any of the group. Temporary clamping of external carotid artery is a safe, simple and cost-effective alternative to embolization for the surgery of large meningiomas. This can be practiced at all the centers.

Measuring true Young's modulus of a cantilevered nanowire: effect of clamping on resonance frequency.

PubMed

Qin, Qingquan; Xu, Feng; Cao, Yongqing; Ro, Paul I; Zhu, Yong

2012-08-20

The effect of clamping on resonance frequency and thus measured Young's modulus of nanowires (NWs) is systematically investigated via a combined experimental and simulation approach. ZnO NWs are used in this work as an example. The resonance tests are performed in situ inside a scanning electron microscope and the NWs are cantilevered on a tungsten probe by electron-beam-induced deposition (EBID) of hydrocarbon. EBID is repeated several times to deposit more hydrocarbons at the same location. The resonance frequency increases with the increasing clamp size until approaching that under the "fixed" boundary condition. The critical clamp size is identified as a function of NW diameter and NW Young's modulus. This work: 1) exemplifies the importance of considering the effect of clamping in measurements of Young's modulus using the resonance method, and 2) demonstrates that the true Young's modulus can be measured if the critical clamp size is reached. Design guidelines on the critical clamp size are provided. Such design guidelines can be extended to other one-dimensional nanostructures such as carbon nanotubes. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Peptide- and proton-driven allosteric clamps catalyze anthrax toxin translocation across membranes

PubMed Central

Das, Debasis; Krantz, Bryan A.

2016-01-01

Anthrax toxin is an intracellularly acting toxin in which sufficient information is available regarding the structure of its transmembrane channel, allowing for detailed investigation of models of translocation. Anthrax toxin, comprising three proteins—protective antigen (PA), lethal factor (LF), and edema factor—translocates large proteins across membranes. Here we show that the PA translocase channel has a transport function in which its catalytic active sites operate allosterically. We find that the phenylalanine clamp (ϕ-clamp), the known conductance bottleneck in the PA translocase, gates as either a more closed state or a more dilated state. Thermodynamically, the two channel states have >300-fold different binding affinities for an LF-derived peptide. The change in clamp thermodynamics requires distant α-clamp and ϕ-clamp sites. Clamp allostery and translocation are more optimal for LF peptides with uniform stereochemistry, where the least allosteric and least efficiently translocated peptide had a mixed stereochemistry. Overall, the kinetic results are in less agreement with an extended-chain Brownian ratchet model but, instead, are more consistent with an allosteric helix-compression model that is dependent also on substrate peptide coil-to-helix/helix-to-coil cooperativity. PMID:27506790

A comparison of 15 Hz sine on-line and off-line magnetic stimulation affecting the voltage-gated sodium channel currents of prefrontal cortex pyramidal neurons

NASA Astrophysics Data System (ADS)

Zheng, Yu; Dong, Lei; Gao, Yang; Dou, Jun-Rong; Li, Ze-yan

2016-10-01

Combined with the use of patch-clamp techniques, repetitive transcranial magnetic stimulation (rTMS) has proven to be a noninvasive neuromodulation tool that can inhibit or facilitate excitability of neurons after extensive research. The studies generally focused on the method: the neurons are first stimulated in an external standard magnetic exposure device, and then moved to the patch-clamp to record electrophysiological characteristics (off-line magnetic exposure). Despite its universality, real-time observation of the effects of magnetic stimulation on the neurons is more effective (on-line magnetic stimulation). In this study, we selected a standard exposure device for magnetic fields acting on mouse prefrontal cortex pyramidal neurons, and described a new method that a patch-clamp setup was modified to allow on-line magnetic stimulation. By comparing the off-line exposure and on-line stimulation of the same magnetic field intensity and frequency affecting the voltage-gated sodium channel currents, we succeeded in proving the feasibility of the new on-line stimulation device. We also demonstrated that the sodium channel currents of prefrontal cortex pyramidal neurons increased significantly under the 15 Hz sine 1 mT, and 2 mT off-line magnetic field exposure and under the 1 mT and 2 mT on-line magnetic stimulation, and the rate of acceleration was most significant on 2 mT on-line magnetic stimulation. This study described the development of a new on-line magnetic stimulator and successfully demonstrated its practicability for scientific stimulation of neurons.

Quick action clamp

NASA Technical Reports Server (NTRS)

Calco, Frank S. (Inventor)

1991-01-01

A quick release toggle clamp that utilizes a spring that requires a deliberate positive action for disengagement is presented. The clamp has a sliding bolt that provides a latching mechanism. The bolt is moved by a handle that tends to remain in an engaged position while under tension.

Rotary slot dog

DOEpatents

Cutburth, Ronald W.; Smauley, David A.

1987-01-01

A clamp or dog is disclosed which preferably comprises a slotted stepped cylindrical body which is inserted into a hole in a workpiece and then fastened to a base or fixture using a screw which is inserted through the slot. The stepped configuration provides an annular clamping surface which securely clamps the workpiece against the base or fixture. The slotted cylindrical configuration permits adjustment of the workpiece and retaining clamp in any direction, i.e., over 360.degree., relative to the mounting position of the screw in the base or fixture.

Simultaneous recording of the action potential and its whole-cell associated ion current on NG108-15 cells cultured over a MWCNT electrode

NASA Astrophysics Data System (ADS)

Morales-Reyes, I.; Seseña-Rubfiaro, A.; Acosta-García, M. C.; Batina, N.; Godínez-Fernández, R.

2016-08-01

It is well known that, in excitable cells, the dynamics of the ion currents (I i) is extremely important to determine both the magnitude and time course of an action potential (A p). To observe these two processes simultaneously, we cultured NG108-15 cells over a multi-walled carbon nanotubes electrode (MWCNTe) surface and arranged a two independent Patch Clamp system configuration (Bi-Patch Clamp). The first system was used in the voltage or current clamp mode, using a glass micropipette as an electrode. The second system was modified to connect the MWCNTe to virtual ground. While the A p was recorded through the micropipette electrode, the MWCNTe was used to measure the underlying whole-cell current. This configuration allowed us to record both the membrane voltage (V m) and the current changes simultaneously. Images acquired by atomic force microscopy (AFM) and scanning electron microscopy (SEM) indicate that cultured cells developed a complex network of neurites, which served to establish the necessary close contact and strong adhesion to the MWCNTe surface. These features were a key factor to obtain the recording of the whole-cell I i with a high signal to noise ratio (SNR). The experimental results were satisfactorily reproduced by a theoretical model developed to simulate the proposed system. Besides the contribution to a better understanding of the fundamental mechanisms involved in cell communication, the developed method could be useful in cell physiology studies, pharmacology and diseases diagnosis.

SiC-Based Miniature High-Temperature Cantilever Anemometer

NASA Technical Reports Server (NTRS)

Okojie, Robert S.; Fralick, Gustave; Saad, George J.

2004-01-01

The figure depicts a miniature cantilever-type anemometer that has been developed as a prototype of compact, relatively nonintrusive anemometers that can function at temperatures up to 600 C and that can be expected to be commercially mass-producible at low cost. The design of this anemometer, and especially the packaging aspect of the design, is intended to enable measurement of turbulence in the high-temperature, high-vibration environment of a turbine engine or in any similar environment. The main structural components of the anemometer include a single-crystal SiC cantilever and two polycrystalline SiC clamping plates, all made from chemical-vapor-deposited silicon carbide. Fabrication of these components from the same basic material eliminates thermal-expansion mismatch, which has introduced spurious thermomechanical stresses in cantilever-type anemometers of prior design. The clamping plates are heavily oxidized to improve electrical insulation at high temperature. A cavity that serves as a receptacle for the clamped end of the cantilever is etched into one end of one clamping plate. Trenches that collectively constitute a socket for a multipin electrical plug (for connection to external electronic circuitry) are etched into the opposite end of this clamping plate. Metal strips for electrical contact are deposited on one face of the other clamping plate. Piezoresistive single-crystal SiC thin-film strain gauges are etched in the n-type SiC epilayer in a Wheatstone-bridge configuration. Metal contact pads on the cantilever that extend into the clamping-receptacle area, are obtained by deposition and patterning using standard semiconductor photolithography and etching methods. The cantilever and the two clamping plates are assembled into a sandwich structure that is then clamped in a stainless-steel housing. The Wheatstone- bridge carrying SiC cantilever with the metal contact pads on the piezoresistors is slid into the receptacle in the bottom clamping plate. The top clamping plate is brought into contact with the bottom plate so that the narrow section of the metal strips on the top clamp plate aligns with the metal contact pads on the cantilever. When the parts are clamped together, the metal strips provide electrical connections between the Wheatstone-bridge contact points and the sides the trenches that constitute the socket for the multipin electrical plug. Hence, to connect the Wheatstone bridge to external circuitry for processing of the anemometer readout, one need only insert the plug in the socket. In operation, the cantilever end of the stainless-steel housing is mounted flush with an engine wall and the unclamped portion of the cantilever is exposed into the flow. The cantilever is deflected in direct proportion to the force induced by component of flow parallel to the engine wall and perpendicular to the broad exposed face of the cantilever. The maximum strain on the cantilever occurs at the clamped edge and is measured by the piezoresistors, which are located there. The corresponding changes in resistance manifest themselves in the output of the Wheatstone bridge.

Automatic, computerized testing of bolts

NASA Technical Reports Server (NTRS)

Carlucci, J., Jr.; Lobb, V. B.; Stoller, F. W.

1970-01-01

System for testing bolts with various platings, lubricants, nuts, and tightening procedures tests 200 fasteners, and processes and summarizes the results, within one month. System measures input torque, nut rotation, bolt clamping force, bolt shank twist, and bolt elongation, data is printed in report form. Test apparatus is described.

Mechanics of wafer bonding: Effect of clamping

NASA Astrophysics Data System (ADS)

Turner, K. T.; Thouless, M. D.; Spearing, S. M.

2004-01-01

A mechanics-based model is developed to examine the effects of clamping during wafer bonding processes. The model provides closed-form expressions that relate the initial geometry and elastic properties of the wafers to the final shape of the bonded pair and the strain energy release rate at the interface for two different clamping configurations. The results demonstrate that the curvature of bonded pairs may be controlled through the use of specific clamping arrangements during the bonding process. Furthermore, it is demonstrated that the strain energy release rate depends on the clamping configuration and that using applied loads usually leads to an undesirable increase in the strain energy release rate. The results are discussed in detail and implications for process development and bonding tool design are highlighted.

Explicit frequency equations of free vibration of a nonlocal Timoshenko beam with surface effects

NASA Astrophysics Data System (ADS)

Zhao, Hai-Sheng; Zhang, Yao; Lie, Seng-Tjhen

2018-02-01

Considerations of nonlocal elasticity and surface effects in micro- and nanoscale beams are both important for the accurate prediction of natural frequency. In this study, the governing equation of a nonlocal Timoshenko beam with surface effects is established by taking into account three types of boundary conditions: hinged-hinged, clamped-clamped and clamped-hinged ends. For a hinged-hinged beam, an exact and explicit natural frequency equation is obtained. However, for clamped-clamped and clamped-hinged beams, the solutions of corresponding frequency equations must be determined numerically due to their transcendental nature. Hence, the Fredholm integral equation approach coupled with a curve fitting method is employed to derive the approximate fundamental frequency equations, which can predict the frequency values with high accuracy. In short, explicit frequency equations of the Timoshenko beam for three types of boundary conditions are proposed to exhibit directly the dependence of the natural frequency on the nonlocal elasticity, surface elasticity, residual surface stress, shear deformation and rotatory inertia, avoiding the complicated numerical computation.

Non-invasive method and apparatus for measuring pressure within a pliable vessel

NASA Technical Reports Server (NTRS)

Shimizu, M. (Inventor)

1983-01-01

A non-invasive method and apparatus is disclosed for measuring pressure within a pliable vessel such as a blood vessel. The blood vessel is clamped by means of a clamping structure having a first portion housing a pressure sensor and a second portion extending over the remote side of the blood vessel for pressing the blood vessel into engagement with the pressure sensing device. The pressure sensing device includes a flat deflectable diaphragm portion arranged to engage a portion of the blood vessel flattened against the diaphragm by means of the clamp structure. In one embodiment, the clamp structure includes first and second semicylindrical members held together by retaining rings. In a second embodiment the clamp structure is of one piece construction having a solid semicylindrical portion and a hollow semicylindrical portion with a longitudinal slot in the follow semicylindrical portion through which a slip the blood vessel. In a third embodiment, an elastic strap is employed for clamping the blood vessel against the pressure sensing device.

Term babies with delayed cord clamping: an approach in preventing anemia (.).

PubMed

Ertekin, Arif Aktug; Nihan Ozdemir, Nilufer; Sahinoglu, Zeki; Gursoy, Tugba; Erbil, Nazan; Kaya, Erdal

2016-09-01

We investigated the effects of delayed and early clamping of the cord on the hematologic status of the baby at birth and at the end of second month. Umbilical cord of 74 babies were clamped in the first 30 s (Group 1) and 76 were clamped at 90-120 s (Group 2). Levels of hemoglobin, hematocrit, iron and ferritin were analyzed from the umbilical cord blood at birth and from the venous samples at the end of second month. Hemoglobin, hematocrit, iron and ferritin levels of cord blood were similar in both groups. However, their levels other than ferritin were higher in Group 2 at the end of second month. Two babies had respiratory distress and twelve neonates received phototherapy in Group 2 whereas only five neonates received phototherapy in Group 1. Term babies to whom delayed cord clamping was performed had improved hematological parameters at the end of second month. Therefore, delaying cord clamping in these babies may be a favorible approach in preventing anemia.

Vibration mode analysis of the proton exchange membrane fuel cell stack

NASA Astrophysics Data System (ADS)

Liu, B.; Liu, L. F.; Wei, M. Y.; Wu, C. W.

2016-11-01

Proton exchange membrane fuel cell (PEMFC) stacks usually undergo vibration during packing, transportation, and serving time, in particular for those used in the automobiles or portable equipment. To study the stack vibration response, based on finite element method (FEM), a mode analysis is carried out in the present paper. Using this method, we can distinguish the local vibration from the stack global modes, predict the vibration responses, such as deformed shape and direction, and discuss the effects of the clamping configuration and the clamping force magnitude on vibration modes. It is found that when the total clamping force remains the same, increasing the bolt number can strengthen the stack resistance to vibration in the clamping direction, but cannot obviously strengthen stack resistance to vibration in the translations perpendicular to clamping direction and the three axis rotations. Increasing the total clamping force can increase both of the stack global mode and the bolt local mode frequencies, but will decrease the gasket local mode frequency.

Prosthetic helping hand

NASA Technical Reports Server (NTRS)

Vest, Thomas W. (Inventor); Carden, James R. (Inventor); Norton, William E. (Inventor); Belcher, Jewell G. (Inventor)

1992-01-01

A prosthetic device for below-the-elbow amputees, having a C-shaped clamping mechanism for grasping cylindrical objects, is described. The clamping mechanism is pivotally mounted to a cuff that fits on the amputee's lower arm. The present invention is utilized by placing an arm that has been amputated below the elbow into the cuff. The clamping mechanism then serves as a hand whenever it becomes necessary for the amputee to grasp a cylindrical object such as a handle, a bar, a rod, etc. To grasp the cylindrical object, the object is jammed against the opening in the C-shaped spring, causing the spring to open, the object to pass to the center of the spring, and the spring to snap shut behind the object. Various sizes of clamping mechanisms can be provided and easily interchanged to accommodate a variety of diameters. With the extension that pivots and rotates, the clamping mechanism can be used in a variety of orientations. Thus, this invention provides the amputee with a clamping mechanism that can be used to perform a number of tasks.

Structural Basis of Transcription Inhibition by Fidaxomicin (Lipiarmycin A3).

PubMed

Lin, Wei; Das, Kalyan; Degen, David; Mazumder, Abhishek; Duchi, Diego; Wang, Dongye; Ebright, Yon W; Ebright, Richard Y; Sineva, Elena; Gigliotti, Matthew; Srivastava, Aashish; Mandal, Sukhendu; Jiang, Yi; Liu, Yu; Yin, Ruiheng; Zhang, Zhening; Eng, Edward T; Thomas, Dennis; Donadio, Stefano; Zhang, Haibo; Zhang, Changsheng; Kapanidis, Achillefs N; Ebright, Richard H

2018-04-05

Fidaxomicin is an antibacterial drug in clinical use for treatment of Clostridium difficile diarrhea. The active ingredient of fidaxomicin, lipiarmycin A3 (Lpm), functions by inhibiting bacterial RNA polymerase (RNAP). Here we report a cryo-EM structure of Mycobacterium tuberculosis RNAP holoenzyme in complex with Lpm at 3.5-Å resolution. The structure shows that Lpm binds at the base of the RNAP "clamp." The structure exhibits an open conformation of the RNAP clamp, suggesting that Lpm traps an open-clamp state. Single-molecule fluorescence resonance energy transfer experiments confirm that Lpm traps an open-clamp state and define effects of Lpm on clamp dynamics. We suggest that Lpm inhibits transcription by trapping an open-clamp state, preventing simultaneous interaction with promoter -10 and -35 elements. The results account for the absence of cross-resistance between Lpm and other RNAP inhibitors, account for structure-activity relationships of Lpm derivatives, and enable structure-based design of improved Lpm derivatives. Copyright © 2018 Elsevier Inc. All rights reserved.

The Carbon-Land Model Intercomparison Project (C-LAMP): A Model-Data Comparison System for Evaluation of Coupled Biosphere-Atmosphere Models

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

Hoffman, Forrest M; Randerson, Jim; Thornton, Peter E

2009-01-01

The need to capture important climate feebacks in general circulation models (GCMs) has resulted in new efforts to include atmospheric chemistry and land and ocean biogeochemistry into the next generation of production climate models, now often referred to as Earth System Models (ESMs). While many terrestrial and ocean carbon models have been coupled to GCMs, recent work has shown that such models can yield a wide range of results, suggesting that a more rigorous set of offline and partially coupled experiments, along with detailed analyses of processes and comparisons with measurements, are warranted. The Carbon-Land Model Intercomparison Project (C-LAMP) providesmore » a simulation protocol and model performance metrics based upon comparisons against best-available satellite- and ground-based measurements (Hoffman et al., 2007). C-LAMP provides feedback to the modeling community regarding model improvements and to the measurement community by suggesting new observational campaigns. C-LAMP Experiment 1 consists of a set of uncoupled simulations of terrestrial carbon models specifically designed to examine the ability of the models to reproduce surface carbon and energy fluxes at multiple sites and to exhibit the influence of climate variability, prescribed atmospheric carbon dioxide (CO{sub 2}), nitrogen (N) deposition, and land cover change on projections of terrestrial carbon fluxes during the 20th century. Experiment 2 consists of partially coupled simulations of the terrestrial carbon model with an active atmosphere model exchanging energy and moisture fluxes. In all experiments, atmospheric CO{sub 2} follows the prescribed historical trajectory from C{sup 4}MIP. In Experiment 2, the atmosphere model is forced with prescribed sea surface temperatures (SSTs) and corresponding sea ice concentrations from the Hadley Centre; prescribed CO{sub 2} is radiatively active; and land, fossil fuel, and ocean CO{sub 2} fluxes are advected by the model. Both sets of experiments have been performed using two different terrestrial biogeochemistry modules coupled to the Community Land Model version 3 (CLM3) in the Community Climate System Model version 3 (CCSM3): The CASA model of Fung, et al., and the carbon-nitrogen (CN) model of Thornton. Comparisons against Ameriflus site measurements, MODIS satellite observations, NOAA flask records, TRANSCOM inversions, and Free Air CO{sub 2} Enrichment (FACE) site measurements, and other datasets have been performed and are described in Randerson et al. (2009). The C-LAMP diagnostics package was used to validate improvements to CASA and CN for use in the next generation model, CLM4. It is hoped that this effort will serve as a prototype for an international carbon-cycle model benchmarking activity for models being used for the Inter-governmental Panel on Climate Change (IPCC) Fifth Assessment Report. More information about C-LAMP, the experimental protocol, performance metrics, output standards, and model-data comparisons from the CLM3-CASA and CLM3-CN models are available at http://www.climatemodeling.org/c-lamp.« less

Tensil Film Clamps And Mounting Block For Viscoelastometers

NASA Technical Reports Server (NTRS)

Stoakley, Diane M.; St. Clair, Anne K.; Little, Bruce D.

1989-01-01

Set of clamps and mounting block developed for use in determining tensile moduli and damping properties of films in manually operated or automated commercial viscoelastometer. These clamps and block provide uniformity of sample gripping and alignment in instrument. Dependence on operator and variability of data greatly reduced.

Diverter bop system and method for a bottom supported offshore drilling rig

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

Roche, J. R.; Alexander, G. G.; Carbaugh, W. L.

1985-06-25

A system and method for installing a fluid flow controller and telescoping spools beneath an offshore bottom supported drilling rig rotary table is disclosed. Upper and lower telescoping spools are provided for initially connecting a Diverter/BOP convertible fluid flow controller between structural casing in the well and a permanent housing beneath the drilling rig rotary table. Clamp means are provided for clamping the rig vent line to an opening in the housing wall of the fluid flow controller during drilling of the borehole through the structural casing in preparation for setting and cementing the conductor casing. In that mode, themore » system is adapted as a diverter system. After the well is drilled for the conductor casing and the conductor casing is cemented and cut off at its top, a mandrel is fitted at the top of the conductor casing to which the lower end of the lower spool may be connected. The system may be used in this configuration as a diverter system, or after removal of the vent line and connection of a kill line to the housing outlet, the system may be used as a low pressure blowout preventer system.« less

30 CFR 77.603 - Clamping of trailing cables to equipment.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Clamping of trailing cables to equipment. 77.603 Section 77.603 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL... UNDERGROUND COAL MINES Trailing Cables § 77.603 Clamping of trailing cables to equipment. Trailing cables...

An ideal clamping analysis for a cross-ply laminate

NASA Technical Reports Server (NTRS)

Valisetty, R. R.; Murthy, P. L. N.; Rehfield, L. W.

1988-01-01

Different elementary clamping models are discussed for a three layer crossply laminate to study the sensitivity of clamping to the definition of cross-sectional rotation. All of these models leave a considerable residual warping at the edges. Using a complimentary energy principle and principle of superposition, an analysis is conducted to reduce this residual warping. This led to the identification of exact interior solution corresponding to the ideal clamping. This study also suggests a presence of stress singularities at the corners and between different layers near the fixed edge.

Clamp force and alignment checking device

DOEpatents

Spicer, John Patrick; Cai, Wayne W.; Chakraborty, Debejyo; Mink, Keith

2017-04-11

A check fixture measures a total clamp force applied by a welder device. The welder device includes a welding horn having a plurality of weld pads and welding anvil having a plurality of weld pads. The check fixture includes a base member operatively supporting a plurality of force sensors. The base member and the force sensors are received between the weld pads of the welding horn and the anvil pads of the welding anvil. Each force sensor is configured to measure an individual clamp force applied thereto by corresponding weld and anvil pads when the base member is received between the welding horn and the welding anvil and the welder device is in the clamped position. The individual clamp forces are used to determine whether the weld and/or anvil pads are worn or misaligned.

Acoustic plane waves incident on an oblique clamped panel in a rectangular duct

NASA Technical Reports Server (NTRS)

Unz, H.; Roskam, J.

1980-01-01

The theory of acoustic plane waves incident on an oblique clamped panel in a rectangular duct was developed from basic theoretical concepts. The coupling theory between the elastic vibrations of the panel (plate) and the oblique incident acoustic plane wave in infinite space was considered in detail, and was used for the oblique clamped panel in the rectangular duct. The partial differential equation which governs the vibrations of the clamped panel (plate) was modified by adding to it stiffness (spring) forces and damping forces. The Transmission Loss coefficient and the Noise Reduction coefficient for oblique incidence were defined and derived in detail. The resonance frequencies excited by the free vibrations of the oblique finite clamped panel (plate) were derived and calculated in detail for the present case.

A novel monolithic piezoelectric actuated flexure-mechanism based wire clamp for microelectronic device packaging.

PubMed

Liang, Cunman; Wang, Fujun; Tian, Yanling; Zhao, Xingyu; Zhang, Hongjie; Cui, Liangyu; Zhang, Dawei; Ferreira, Placid

2015-04-01

A novel monolithic piezoelectric actuated wire clamp is presented in this paper to achieve fast, accurate, and robust microelectronic device packaging. The wire clamp has compact, flexure-based mechanical structure and light weight. To obtain large and robust jaw displacements and ensure parallel jaw grasping, a two-stage amplification composed of a homothetic bridge type mechanism and a parallelogram leverage mechanism was designed. Pseudo-rigid-body model and Lagrange approaches were employed to conduct the kinematic, static, and dynamic modeling of the wire clamp and optimization design was carried out. The displacement amplification ratio, maximum allowable stress, and natural frequency were calculated. Finite element analysis (FEA) was conducted to evaluate the characteristics of the wire clamp and wire electro discharge machining technique was utilized to fabricate the monolithic structure. Experimental tests were carried out to investigate the performance and the experimental results match well with the theoretical calculation and FEA. The amplification ratio of the clamp is 20.96 and the working mode frequency is 895 Hz. Step response test shows that the wire clamp has fast response and high accuracy and the motion resolution is 0.2 μm. High speed precision grasping operations of gold and copper wires were realized using the wire clamper.

[Analysis of brain hemometabolism behavior during carotid endarterectomy with temporary clamping.].

PubMed

Duval Neto, Gastão Fernandes; Niencheski, Augusto H

2004-04-01

Carotid endarterectomy with temporary clamping changes cerebral blood flow and cerebral metabolic oxygen demand ratio with consequent oligemic hypoxia or hemometabolic uncoupling. This study aimed at identifying changes in brain hemometabolism, evaluated through changes in oxyhemoglobin saturation in internal jugular vein bulb (SvjO2) during carotid endarterectomy with clamping, and at correlating these changes with potentially interfering factors, mainly end tidal CO2 pressure (P ET CO2) and cerebral perfusion pressure (CPP). Sixteen patients with unilateral carotid stenotic disease scheduled to carotid endarterectomy with carotid arterial clamping were enrolled in this study. Parameters including internal jugular bulb oxyhemoglobin saturation, stump pressure and end tidal CO2 pressure were measured at the following moments: M1 - pre-clamping; M2 - 3 minutes after clamping; M3 - pre-unclamping; M4 - post-unclamping). The comparison among SvjO2 (%, mean +/- SD) in all studied periods has shown differences between those recorded in moments M1 (52.25 +/- 7.87) and M2 (47.43 +/- 9.19). This initial decrease stabilized during temporary clamping, showing decrease in the comparison between M2 and M3 (46.56 +/- 9.25), without statistical significance (p = ns). At post-unclamping, M4 (47.68 +/- 9.12), SvjO2 was increased as compared to M2 and M3 clamping stages, however it was still lower than that of pre-clamping stage M1.(M4 x M1 - p < 0.04) This SvjO2 decrease was followed by significant cerebral perfusion pressure (stump pressure) decrease. Factors influencing this brain hemometabolic uncoupling trend were correlated to P ET CO2. The comparison between CPP and SvjO2 showed weak correlation devoid of statistical significance. In the conditions of our study, SvjO2 measurement is a fast and effective way of clinically monitoring changes in CBF/CMRO2 ratio. Temporary carotid clamping implies in a trend towards brain hemometabolic uncoupling and, as a consequence, to oligemic ischemia; cerebral perfusion pressure does not assesses brain hemometabolic status (CBF and CMRO2 ratio); hypocapnia, may lead to brain hemometabolic uncoupling; P ET CO2 monitoring is an innocuous and efficient way to indirectly monitor PaCO2 preventing inadvertent hypocapnia and its deleterious effects on CBF/CMRO2 ratio during temporary carotid clamping.

Laser-assisted patch clamping: a methodology

NASA Technical Reports Server (NTRS)

Henriksen, G. H.; Assmann, S. M.; Evans, M. L. (Principal Investigator)

1997-01-01

Laser microsurgery can be used to perform both cell biological manipulations, such as targeted cell ablation, and molecular genetic manipulations, such as genetic transformation and chromosome dissection. In this report, we describe a laser microsurgical method that can be used either to ablate single cells or to ablate a small area (1-3 microns diameter) of the extracellular matrix. In plants and microorganisms, the extracellular matrix consists of the cell wall. While conventional patch clamping of these cells, as well as of many animal cells, requires enzymatic digestion of the extracellular matrix, we illustrate that laser microsurgery of a portion of the wall enables patch clamp access to the plasma membrane of higher plant cells remaining situated in their tissue environment. What follows is a detailed description of the construction and use of an economical laser microsurgery system, including procedures for single cell and targeted cell wall ablation. This methodology will be of interest to scientists wishing to perform cellular or subcellular ablation with a high degree of accuracy, or wishing to study how the extracellular matrix affects ion channel function.

Uniaxial Strain Redistribution in Corrugated Graphene: Clamping, Sliding, Friction, and 2D Band Splitting.

PubMed

Wang, Xuanye; Tantiwanichapan, Khwanchai; Christopher, Jason W; Paiella, Roberto; Swan, Anna K

2015-09-09

Graphene is a promising material for strain engineering based on its excellent flexibility and elastic properties, coupled with very high electrical mobility. In order to implement strain devices, it is important to understand and control the clamping of graphene to its support. Here, we investigate the limits of the strong van der Waals interaction on friction clamping. We find that the friction of graphene on a SiO2 substrate can support a maximum local strain gradient and that higher strain gradients result in sliding and strain redistribution. Furthermore, the friction decreases with increasing strain. The system used is graphene placed over a nanoscale SiO2 grating, causing strain and local strain variations. We use a combination of atomic force microscopy and Raman scattering to determine the friction coefficient, after accounting for compression and accidental charge doping, and model the local strain variation within the laser spot size. By using uniaxial strain aligned to a high crystal symmetry direction, we also determine the 2D Raman Grüneisen parameter and deformation potential in the zigzag direction.

Spectral infrared hemispherical reflectance measurements for LDEF tray clamps

NASA Technical Reports Server (NTRS)

Wood, Bobby E.; Cromwell, Brian K.; Pender, Charles W.; Shepherd, Seth D.

1992-01-01

This paper describes infrared hemispherical reflectance measurements (2-15 microns) that were made on 58 chromic acid anodized tray clamps retrieved from the LDEF spacecraft. These clamps were used for maintaining the experiments in place and were located at various locations about the spacecraft. Changes in reflectance of the tray clamps at these locations were compared with atomic oxygen fluxes at the same locations. A decrease in absorption band depth was seen for the surfaces exposed to space indicating that there was some surface layer erosion. In all of the surfaces measured, little evidence of contamination was observed and none of the samples showed evidence of the brown nicotine stain that was so prominent in other experiments. Total emissivity values were calculated for both exposed and unexposed tray clamp surfaces. Only small differences, usually less than 1 percent, were observed. The spectral reflectances were measured using a hemi-ellipsoidal mirror reflectometer matched with an interferometer spectrometer. The rapid scanning capability of the interferometer allowed the reflectance measurements to be made in a timely fashion. The ellipsoidal mirror has its two foci separated by 2 inches and located on the major axis. A blackbody source was located at one focus while the tray clamp samples were located at the conjugate focus. The blackbody radiation was modulated and then focused by the ellipsoid onto the tray clamps. Radiation reflected from the tray clamp was sampled by the interferometer by viewing through a hole in the ellipsoid. A gold mirror (reflectance approximately 98 percent) was used as the reference surface.

Cerebral hemodynamic changes and electroencephalography during carotid endarterectomy

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

Algotsson, L.; Messeter, K.; Rehncrona, S.

Some patients undergoing endarterectomy for occlusive carotid artery disease run a risk of brain ischemia during cross-clamping of the artery. The present study of 15 patients was undertaken to evaluate changes in cerebral blood flow (CBF), as measured with an intravenous (IV) tracer (133Xenon) technique, and to relate CBF changes to changes in the electroencephalogram (EEG). CBF was measured before and after induction of anesthesia, during cross-clamping of the carotid artery, after release of the clamps, and at 24 hours after the operation. All the patients were anesthetized with methohexitone, fentanyl, and nitrous oxide and oxygen. EEG was continuously recordedmore » during the operation. Carotid artery shunts were not used. In 8 patients, cross-clamping of the carotid artery did not influence the EEG. In this group of patients, induction of anesthesia caused a 38% decrease in CBF, which presumably reflects the normal reaction to the anesthetic agent given. There were no further changes in CBF during cross-clamping. In 7 patients, the EEG showed signs of deterioration during the intraoperative vascular occlusion. In these patients, anesthesia did not cause any CBF change, whereas cross-clamping the artery induced a 33% decrease in CBF. In individual patients, the severity of EEG changes correlated with the decrease in CBF. The absence of a change in CBF by anesthesia and a decrease due to cross-clamping of the carotid artery may be explained by the presence of a more advanced cerebrovascular disease and an insufficiency to maintain CBF during cross-clamping.« less

78 FR 79338 - Airworthiness Directives; Bombardier, Inc. Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-30

...We propose to adopt a new airworthiness directive (AD) for certain Bombardier, Inc. Model DHC-8-400 series airplanes. This proposed AD was prompted by reports of missing clamps that are required to provide positive separation between the alternating current (AC) feeder cables and the hydraulic line of the landing gear alternate extension. This proposed AD would require inspecting for missing clamps, and related investigative and corrective actions if necessary. We are proposing this AD to detect and correct chafing of the AC feeder cable. A chafed and arcing AC feeder cable could puncture the adjacent hydraulic line, which, in combination with the use of the alternate extension system, could result in an in-flight fire.

Design and Construction of a Small Whole Body Inhalation Chamber

DTIC Science & Technology

2010-07-30

by 12 7/8 inch high) were solvent welded onto this base using Weldon 4 (Ridout Plastics, San Diego CA). On the inside of each side wall a 2 inch...together using one inch spring clamps (Just Clamps, model 616,Atlanta Ga) on their respective flanges. These clamps were spaced evenly around the

Analysis of impactor residues in tray clamps from the Long Duration Exposure Facility. Part 2: Clamps from Bay B of the satellite

NASA Technical Reports Server (NTRS)

Bernhard, Ronald P.; Zolensky, Michael E.

1994-01-01

The Long Duration Exposure Facility (LDEF) was placed in low-Earth orbit (LEO) in 1984 and recovered 5.7 years later. The LDEF was host to several individual experiments specifically designed to characterize critical aspects of meteoroid and debris environment in LEO. However, it was realized from the beginning that the most efficient use of the satellite would be to examine the entire surface for impact features. In this regard, particular interest centered on common exposed materials that faced in all LDEF pointing directions. Among the most important of these materials was the tray clamps. Therefore, in an effort to better understand the nature of particulates in LEO and their effects on spacecraft hardware, residues found in impact features on LDEF tray clamp surfaces are being analyzed. This catalog presents all data from clamps from Bay B of the LDEF. NASA Technical Memorandum 104759 has cataloged impacts that occurred on Bay B (published March 1993). Subsequent catalogs will include clamps from succeeding bays of the satellite.

Micromolded PDMS planar electrode allows patch clamp electrical recordings from cells.

PubMed

Klemic, Kathryn G; Klemic, James F; Reed, Mark A; Sigworth, Fred J

2002-06-01

The patch clamp method measures membrane currents at very high resolution when a high-resistance 'gigaseal' is established between the glass microelectrode and the cell membrane (Pflugers Arch. 391 (1981) 85; Neuron 8 (1992) 605). Here we describe the first use of the silicone elastomer, poly(dimethylsiloxane) (PDMS), for patch clamp electrodes. PDMS is an attractive material for patch clamp recordings. It has low dielectric loss and can be micromolded (Annu. Rev. Mat. Sci. 28 (1998) 153) into a shape that mimics the tip of the glass micropipette. Also, the surface chemistry of PDMS may be altered to mimic the hydrophilic nature of glass (J. Appl. Polym. Sci. 14 (1970) 2499; Annu. Rev. Mat. Sci. 28 (1998) 153), thereby allowing a high-resistance seal to a cell membrane. We present a planar electrode geometry consisting of a PDMS partition with a small aperture sealed between electrode and bath chambers. We demonstrate that a planar PDMS patch electrode, after oxidation of the elastomeric surface, permits patch clamp recording on Xenopus oocytes. Our results indicate the potential for high-throughput patch clamp recording with a planar array of PDMS electrodes.

Linear ultrasonic motor for absolute gravimeter.

PubMed

Jian, Yue; Yao, Zhiyuan; Silberschmidt, Vadim V

2017-05-01

Thanks to their compactness and suitability for vacuum applications, linear ultrasonic motors are considered as substitutes for classical electromagnetic motors as driving elements in absolute gravimeters. Still, their application is prevented by relatively low power output. To overcome this limitation and provide better stability, a V-type linear ultrasonic motor with a new clamping method is proposed for a gravimeter. In this paper, a mechanical model of stators with flexible clamping components is suggested, according to a design criterion for clamps of linear ultrasonic motors. After that, an effect of tangential and normal rigidity of the clamping components on mechanical output is studied. It is followed by discussion of a new clamping method with sufficient tangential rigidity and a capability to facilitate pre-load. Additionally, a prototype of the motor with the proposed clamping method was fabricated and the performance tests in vertical direction were implemented. Experimental results show that the suggested motor has structural stability and high dynamic performance, such as no-load speed of 1.4m/s and maximal thrust of 43N, meeting the requirements for absolute gravimeters. Copyright © 2017 Elsevier B.V. All rights reserved.

Laparoscopic partial nephrectomy for renal tumor: Nagoya experience.

PubMed

Yoshikawa, Yoko; Ono, Yoshinari; Hattori, Ryohei; Gotoh, Momokazu; Yoshino, Yasushi; Katsuno, Satoshi; Katoh, Masashi; Ohshima, Shinichi

2004-08-01

To clarify the indication for a vascular clamp during laparoscopic partial nephrectomy, the clinical results of 17 patients who underwent the procedure for small renal tumors were reviewed. Seventeen patients with renal tumors were enrolled in our laparoscopic partial nephrectomy program between October 1999 and November 2003. During laparoscopy, a vascular clamp was used to remove the tumor mass and suture the incised renal parenchyma and urinary collecting system in 8 patients who had less-than-1-cm-thick renal parenchyma between the mass and the renal sinus or calices. In the remaining 9 patients, who had 1-cm-or-more-thick renal parenchyma between the mass and sinus or calices, renal bleeding was controlled using ultrasonic scissors, gauze tampon, argon beam coagulator, and fibrin glue. Sixteen patients were successfully treated with laparoscopy; one required conversion to open surgery because of uncontrollable bleeding. The average operative time was 4.5 hours, and average estimated bleeding volume was 301 mL. In the 8 patients requiring vascular clamping by forceps, the average ischemic time was 25 minutes. In all patients, the tumor mass was completely removed with negative surgical margins, and renal function was preserved. Three patients had prolonged urinary leakage for a mean of 21 days. Laparoscopic partial nephrectomy offers many advantages, including surgery that is both nephron sparing and minimally invasive. A vascular clamp was indicated for patients with less-than-1-cm-thick renal parenchyma between the tumor mass and renal sinus or calices.

Hemodynamics on abrupt stoppage of centrifugal pumps during left ventricular assist.

PubMed

Kono, S; Nishimura, K; Nishina, T; Akamatsu, T; Komeda, M

2000-01-01

A magnetically suspended centrifugal pump (MSCP), developed for long-term ventricular assist, is reliable and durable because it has no shaft or seal. However, with nonvalve pumps such as a MSCP, regurgitation occurs when they accidentally stop without cannula clamping. We investigated the hemodynamics during temporary stoppage of a MSCP being used as a left ventricular assist system (LVAS), comparing two inflow cannulation sites. In four sheep (weight, 35-45 kg), microspheres were injected into the left main coronary artery to induce heart failure. An outflow cannula was sutured onto the descending aorta, and two inflow cannulae were inserted into the left atrium and the left ventricle. The MSCP was stopped with both the left ventricular cannula and left atrial cannula clamped, and the hemodynamics and P-V loops were recorded. Each cannula was then unclamped in order, and similar parameters were recorded. LVEDP increased at unclamping of the left ventricular cannula (ULVC), and rose further at unclamping of the left atrial cannula (ULAC). Aortic pressure did not change at ULVC, but decreased at ULAC. The effective systemic flow that subtracted the regurgitant flow through the MSCP from left ventricular output was half at ULVC and almost 0 at ULAC. When stopping centrifugal pumps without circuit clamping, hemodynamic deterioration is less at ULVC than at ULAC. This finding suggests that left ventricular inflow cannulation is recommended to allow more time in emergency situations.

Analysis of the Effects of Calcium or Magnesium on Voltage-Clamp Currents in Perfused Squid Axons Bathed in Solutions of High Potassium

PubMed Central

Rojas, Eduardo; Taylor, Robert E.; Atwater, Illani; Bezanilla, Francisco

1969-01-01

Isolated axons from the squid, Dosidicus gigas, were internally perfused with potassium fluoride solutions. Membrane currents were measured following step changes of membrane potential in a voltage-clamp arrangement with external isosmotic solution changes in the order: potassium-free artificial seawater; potassium chloride; potassium chloride containing 10, 25, 40 or 50, mM calcium or magnesium; and potassium-free artificial seawater. The following results suggest that the currents measured under voltage clamp with potassium outside and inside can be separated into two components and that one of them, the predominant one, is carried through the potassium system. (a) Outward currents in isosmotic potassium were strongly and reversibly reduced by tetraethylammonium chloride. (b) Without calcium or magnesium a progressive increase in the nontime-dependent component of the currents (leakage) occurred. (c) The restoration of calcium or magnesium within 15–30 min decreases this leakage. (d) With 50 mM divalent ions the steady-state current-voltage curve was nonlinear with negative resistance as observed in intact axons in isosmotic potassium. (e) The time-dependent components of the membrane currents were not clearly affected by calcium or magnesium. These results show a strong dependence of the leakage currents on external calcium or magnesium concentration but provide no support for the involvement of calcium or magnesium in the kinetics of the potassium system. PMID:5823216

Analysis of the effects of calcium or magnesium on voltage-clamp currents in perfused squid axons bathed in solutions of high potassium.

PubMed

Rojas, E; Taylor, R E; Atwater, I; Bezanilla, F

1969-10-01

Isolated axons from the squid, Dosidicus gigas, were internally perfused with potassium fluoride solutions. Membrane currents were measured following step changes of membrane potential in a voltage-clamp arrangement with external isosmotic solution changes in the order: potassium-free artificial seawater; potassium chloride; potassium chloride containing 10, 25, 40 or 50, mM calcium or magnesium; and potassium-free artificial seawater. The following results suggest that the currents measured under voltage clamp with potassium outside and inside can be separated into two components and that one of them, the predominant one, is carried through the potassium system. (a) Outward currents in isosmotic potassium were strongly and reversibly reduced by tetraethylammonium chloride. (b) Without calcium or magnesium a progressive increase in the nontime-dependent component of the currents (leakage) occurred. (c) The restoration of calcium or magnesium within 15-30 min decreases this leakage. (d) With 50 mM divalent ions the steady-state current-voltage curve was nonlinear with negative resistance as observed in intact axons in isosmotic potassium. (e) The time-dependent components of the membrane currents were not clearly affected by calcium or magnesium. These results show a strong dependence of the leakage currents on external calcium or magnesium concentration but provide no support for the involvement of calcium or magnesium in the kinetics of the potassium system.

21 CFR 876.4300 - Endoscopic electrosurgical unit and accessories.

Code of Federal Regulations, 2010 CFR

2010-04-01

... Endoscopic electrosurgical unit and accessories. (a) Identification. An endoscopic electrosurgical unit and... device includes the electrosurgical generator, patient plate, electric biopsy forceps, electrode, flexible snare, electrosurgical alarm system, electrosurgical power supply unit, electrical clamp, self...

Stability Formulation for Integrated Opto-mechanic Phase Shifters.

PubMed

Ozer, Yigit; Kocaman, Serdar

2018-01-31

Stability of opto-mechanical phase shifters consisting of waveguides and non-signal carrying control beams is investigated thoroughly and a formula determining the physical limitations has been proposed. Suggested formulation is not only beneficial to determine physical strength of the system but also advantageous to guess the response of the output to the fabrication errors. In the iterative analysis of cantilever and double-clamped beam geometrical configurations, the stability condition is revealed under the strong inter-dependence of the system parameters such as input power, device length and waveguide separation. Numerical calculations involving effective index modifications and opto-mechanic movements show that well-known cantilever beams are unstable and inadequate to generate φ = 180° phase difference, while double-clamped beam structures can be utilized to build functional devices. Ideal operation conditions are also presented in terms of both the device durability and the controllability of phase evolution.

Intermittent chest tube clamping may shorten chest tube drainage and postoperative hospital stay after lung cancer surgery: a propensity score matching analysis.

PubMed

Yan, Shi; Wang, Xing; Wang, Yaqi; Lv, Chao; Wang, Yuzhao; Wang, Jia; Yang, Yue; Wu, Nan

2017-12-01

Postoperative pleural drainage markedly influences the length of hospital stay and the financial costs of medical care. The safety of chest tube clamping before removal has been documented. This study aims to determine if intermittent chest tube clamping shortens the duration of chest tube drainage and hospital stay after lung cancer surgery. We retrospectively analyzed 285 consecutive patients with operable lung cancer treated using lobectomy and systematic mediastinal lymphadenectomy. The chest tube management protocol in our institution was changed in January 2014, and thus, 222 patients (clamping group) were managed with intermittent chest tube clamping, while 63 patients (control group) were managed with a traditional protocol. Propensity score matching at a 1:1 ratio was applied to balance variables potentially affecting the duration of chest tube drainage. Analyses were performed to compare drainage duration and postoperative hospital stay between the two groups in the matched cohort. Multivariate logistic regression analyses were performed to predict the factors associated with chest tube drainage duration. The rates of thoracocentesis after chest tube removal were similar between the clamping and control groups in the whole cohort (0.5% vs. 1.6%, P=0.386). The rates of pyrexia were also comparable in the two groups (2.3% vs. 3.2%, P=0.685). After propensity score matching, 61 cases remained in each group. Both chest tube drainage duration (3.9 vs. 4.8 days, P=0.001) and postoperative stay (5.7 vs. 6.4 days, P=0.025) were significantly shorter in the clamping group than in the control group. Factors significantly associated with shorter chest tube drainage duration were female sex, chest tube clamping, left lobectomy, and video-assisted thoracoscopic surgery (VATS) (P<0.05). Intermittent postoperative chest tube clamping may decrease the duration of chest tube drainage and postoperative hospital stay while maintaining patient safety.

Calcium Homeostasis Modulator 1-Like Currents in Rat Fungiform Taste Cells Expressing Amiloride-Sensitive Sodium Currents.

PubMed

Bigiani, Albertino

2017-05-01

Salt reception by taste cells is still the less understood transduction process occurring in taste buds, the peripheral sensory organs for the detection of food chemicals. Although there is evidence suggesting that the epithelial sodium channel (ENaC) works as sodium receptor, yet it is not clear how salt-detecting cells signal the relevant information to nerve endings. Taste cells responding to sweet, bitter, and umami substances release ATP as neurotransmitter through a nonvesicular mechanism. Three different channel proteins have been proposed as conduit for ATP secretion: pannexin channels, connexin hemichannels, and calcium homeostasis modulator 1 (CALHM1) channels. In heterologous expression systems, these channels mediate outwardly rectifying membrane currents with distinct biophysical and pharmacological properties. I therefore tested whether also salt-detecting taste cells were endowed with these currents. To this aim, I applied the patch-clamp techniques to single cells in isolated taste buds from rat fungiform papillae. Salt-detecting cells were functionally identified by exploiting the effect of amiloride, which induces a current response by shutting down ENaCs. I looked for the presence of outwardly rectifying currents by using appropriate voltage-clamp protocols and specific pharmacological tools. I found that indeed salt-detecting cells possessed these currents with properties consistent with the presence, at least in part, of CALHM1 channels. Unexpectedly, CALHM1-like currents in taste cells were potentiated by known blockers of pannexin, suggesting a possible inhibitory action of this protein on CALMH1. These findings indicate that communication between salt-detecting cells and nerve endings might involve ATP release by CALMH1 channels. © The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Developing an evidence-based nursing protocol on wound drain management for total joint arthroplasty.

PubMed

Tsang, Lap Fung

2015-05-01

Although various drains have long been used for many years in total joint replacement, there is a paucity of evidence for the benefit of drain applications. Evidence suggests inconsistent practice in the use of drainage systems, whether intermittently applying suction or free of suction in the application of drainage systems, as well as the optimal timing for wound drain removal. It aimed to perform a systematic review to develop an evidence-based nursing protocol to manage wound drainage following total joint arthroplasty. A comprehensive systematic review of available evidence up to 2013. Searches of the EMBASE, Cochrane library, CINAHL, Medline electronic databases and an internet search by Yahoo and Google engine returned 2840 records, of which 11 met the inclusion criteria for this review. A further two papers were obtained through scanning the reference lists of those articles included from the initial literature search. Different clamping times were retrieved from the literature. A protocol was adapted for clinical application according to the summary of the retrieved information. It is suggested that clamping is performed 1 h after the insertion of suction drains post-operatively in the operating theatre. Wound drains should be clamped for 1 h if blood loss is more than 600 ml in 6 h in first 24 h. Wound drains should be clamped for 1 h if blood loss is more than 800 ml in 8 h thereafter. It is suggested that the drainage reservoir bottle should be mark and findings recorded in line with the principle of drain clamping. This means that the amount of drainage is measured and recorded every 6 h in first 24 h and every 8 h thereafter. It is suggested that wound drains should be remove before 48 h after TJR. If blood loss is less than 50 ml in past 6 h or less than 70 ml in past 8 h, the drain should be remove and the wound site should be monitored closely. This paper has guided nurses to develop an evidence-based protocol to improve patient care on wound drain management. Further study is necessary to evaluate the effectiveness of the protocol. Copyright © 2014 Elsevier Ltd. All rights reserved.

Dicarbonyl stress and glyoxalase enzyme system regulation in human skeletal muscle.

PubMed

Mey, Jacob T; Blackburn, Brian K; Miranda, Edwin R; Chaves, Alec B; Briller, Joan; Bonini, Marcelo G; Haus, Jacob M

2018-02-01

Skeletal muscle insulin resistance is a hallmark of Type 2 diabetes (T2DM) and may be exacerbated by protein modifications by methylglyoxal (MG), known as dicarbonyl stress. The glyoxalase enzyme system composed of glyoxalase 1/2 (GLO1/GLO2) is the natural defense against dicarbonyl stress, yet its protein expression, activity, and regulation remain largely unexplored in skeletal muscle. Therefore, this study investigated dicarbonyl stress and the glyoxalase enzyme system in the skeletal muscle of subjects with T2DM (age: 56 ± 5 yr.; BMI: 32 ± 2 kg/m 2 ) compared with lean healthy control subjects (LHC; age: 27 ± 1 yr.; BMI: 22 ± 1 kg/m 2 ). Skeletal muscle biopsies obtained from the vastus lateralis at basal and insulin-stimulated states of the hyperinsulinemic (40 mU·m -2 ·min -1 )-euglycemic (5 mM) clamp were analyzed for proteins related to dicarbonyl stress and glyoxalase biology. At baseline, T2DM had increased carbonyl stress and lower GLO1 protein expression (-78.8%), which inversely correlated with BMI, percent body fat, and HOMA-IR, while positively correlating with clamp-derived glucose disposal rates. T2DM also had lower NRF2 protein expression (-31.6%), which is a positive regulator of GLO1, while Keap1 protein expression, a negative regulator of GLO1, was elevated (207%). Additionally, insulin stimulation during the clamp had a differential effect on NRF2, Keap1, and MG-modified protein expression. These data suggest that dicarbonyl stress and the glyoxalase enzyme system are dysregulated in T2DM skeletal muscle and may underlie skeletal muscle insulin resistance. Whether these phenotypic differences contribute to the development of T2DM warrants further investigation.

NIMBY, CLAMP, and the location of new nuclear-related facilities: U.S. national and 11 site-specific surveys.

PubMed

Greenberg, Michael R

2009-09-01

Public and political opposition have made finding locations for new nuclear power plants, waste management, and nuclear research and development facilities a challenge for the U.S. government and the nuclear industry. U.S. government-owned properties that already have nuclear-related activities and commercial nuclear power generating stations are logical locations. Several studies and utility applications to the Nuclear Regulatory Commission suggest that concentrating locations at major plants (CLAMP) has become an implicit siting policy. We surveyed 2,101 people who lived within 50 miles of 11 existing major nuclear sites and 600 who lived elsewhere in the United States. Thirty-four percent favored CLAMP for new nuclear power plants, 52% for waste management facilities, and 50% for new nuclear laboratories. College educated, relatively affluent male whites were the strongest CLAMP supporters. They disproportionately trusted those responsible for the facilities and were not worried about existing nuclear facilities or other local environmental issues. Notably, they were concerned about continuing coal use. Not surprisingly, CLAMP proponents tended to be familiar with their existing local nuclear site. In short, likely CLAMP sites have a large and politically powerful core group to support a CLAMP policy. The challenge to proponents of nuclear technologies will be to sustain this support and expand the base among those who clearly are less connected and receptive to new nearby sites.

Delivery room management of term and preterm newly born infants.

PubMed

Saugstad, Ola Didrik

2015-01-01

Delivery room management, especially in the first 'golden' minute, is of the utmost importance. An exact and universal definition of when a baby is born is needed to obtain agreement on what is meant by the first minute of life. Education of young girls is a basic requirement to optimize the health of the mother and baby. Interventions in pregnancy should as far as possible be evidence based. Antenatal care, the selection of birth mode and antenatal steroid therapy when indicated also contribute to obtaining the best outcome. Delayed cord clamping is recommended for both preterm and term infants. However, more data are needed regarding the most immature infants. Routine suctioning of the mouth and airways is not required. Thermal control is important - keep the temperature in the delivery room at 26°C and wrap infants <28 weeks of gestation in plastic. However, this procedure does not reduce mortality. Since delayed cord clamping increases mean birth weight by approximately 30 g/kg, the present birth weight charts based on early clamping need to be corrected. Preterm infants in need of ventilatory support should start with CPAP from the first breath. A T-piece device seems to have some advantages compared to self-inflating bags. Surfactant instillation is often not needed prophylactically provided the mother has received antenatal steroids. Less invasive methods for administering surfactant may be useful. If ventilatory support is needed, start with air in term and near-term infants. For babies of 29-33 weeks of gestation start with 21-30% oxygen and for infants <29 weeks start with 30% oxygen and adjust according to the response obtained. © 2015 S. Karger AG, Basel.

Cardiac troponin I is modified in the myocardium of bypass patients.

PubMed

McDonough, J L; Labugger, R; Pickett, W; Tse, M Y; MacKenzie, S; Pang, S C; Atar, D; Ropchan, G; Van Eyk, J E

2001-01-02

Selective proteolysis of cardiac troponin I (cTnI) is a proposed mechanism of contractile dysfunction in stunned myocardium, and the presence of cTnI degradation products in serum may reflect the functional state of the remaining viable myocardium. However, recent swine and canine studies have not demonstrated stunning-dependent cTnI degradation. To address the universality of cTnI modification, myocardial biopsy samples were obtained from coronary artery bypass patients (n=37) before and 10 minutes after removal of cross-clamp. Analysis of biopsy samples for cTnI by Western blotting revealed a spectrum of modified cTnI products in myocardium both before and after cross-clamp, including degradation products (7 products resulting from differential N- and C-terminal processing) and covalent complexes (3 products). In particular, a 22-kDa cTnI degradation product with C-terminal proteolysis was identified, which may represent an initial ischemia-dependent cTnI modification, similar to cTnI(1-193) observed in stunned rat myocardium. Although no systematic change in amount of modified cTnI was observed, subgroups of patients displayed an increase (n=10, 85+/-5% of cTnI remaining intact before cross-clamp versus 75+/-5% after) or a decrease (n=12, 67+/-5% before versus 78+/-5% after). Electron microscopy demonstrated normal ultrastructure in biopsy samples, which suggests no necrosis was present. In addition, cTnI modification products were observed in serum through a modified SDS-PAGE methodology. cTnI modification, in particular proteolysis, occurs in myocardium of bypass patients and may play a key role in stunning in some bypass patients.

Tensile film clamps and mounting block for the rheovibron and autovibron viscoelastometer

NASA Technical Reports Server (NTRS)

Stoakley, Diane M. (Inventor); St.clair, Anne K. (Inventor); Little, Bruce D. (Inventor)

1989-01-01

A set of film clamps and a mounting block for use in the determination of tensile modulus and damping properties of films in a manually operated or automated Rheovibron is diagrammed. These clamps and mounting block provide uniformity of sample gripping and alignment in the instrument. Operator dependence and data variability are greatly reduced.

Plastic Clamp Retains Clevis Pin

NASA Technical Reports Server (NTRS)

Cortes, R. G.

1983-01-01

Plastic clamp requires no special installation or removal tools. Clamp slips easily over end of pin. Once engaged in groove, holds pin securely. Installed and removed easily without special tools - screwdriver or putty knife adequate for prying out of groove. Used to retain bearings, rollers pulleys, other parts that rotate. Applications include slowly and intermittently rotating parts in appliances.

Flow characterization and patch clamp dose responses using jet microfluidics in a tubeless microfluidic device.

PubMed

Resto, Pedro J; Bhat, Abhishek; Stava, Eric; Lor, Chong; Merriam, Elliot; Diaz-Rivera, Ruben E; Pearce, Robert; Blick, Robert; Williams, Justin C

2017-11-01

Surface tension passive pumping is a way to actuate flow without the need for pumps, tubing or valves by using the pressure inside small drop to move liquid via a microfluidic channel. These types of tubeless devices have typically been used in cell biology. Herein we present the use of tubeless devices as a fluid exchange platform for patch clamp electrophysiology. Inertia from high-speed droplets and jets is used to create flow and perform on-the-fly mixing of solutions. These are then flowed over GABA transfected HEK cells under patch in order to perform a dose response analysis. TIRF imaging and electrical recordings are used to study the fluid exchange properties of the microfluidic device, resulting in 0-90% fluid exchange times of hundreds of milliseconds. COMSOL is used to model flow and fluid exchange within the device. Patch-clamping experiments show the ability to use high-speed passive pumping and its derivatives for studying peak dose responses, but not for studying ion channel kinetics. Our system results in fluid exchange times slower than when using a standard 12-barrel application system and is not as stable as traditional methods, but it offers a new platform with added functionality. Surface tension passive pumping and tubeless devices can be used in a limited fashion for electrophysiology. Users may obtain peak dose responses but the system, in its current form, is not capable of fluid exchange fast enough to study the kinetics of most ion channels. Copyright © 2017 Elsevier B.V. All rights reserved.

Intraoperative evaluation of renal blood flow during laparoscopic partial nephrectomy with a novel Doppler system.

PubMed

Mues, Adam C; Okhunov, Zhamshid; Badani, Ketan; Gupta, Mantu; Landman, Jaime

2010-12-01

Hemostasis remains a major challenge associated with laparoscopic renal surgery. We evaluated a cost-effective novel Doppler probe (DP) for assessment of vascular control during laparoscopic partial nephrectomy (LPN). We prospectively collected data during LPN procedures. We documented tumor location and size as well as subjective quality of the hilar dissection. The DP was compared with our standard intraoperative ultrasound system (SUS) for the ability to detect blood flow during hilar dissection and to determine parenchymal ischemia around the tumor after clamping of the renal vessels. Twenty patients underwent LPN by a single surgeon. The mean tumor size was 3.0 cm (range: 1.2-6.3 cm). The times to assess the kidney using the SUS and DP were 68.6 seconds (range: 20-155) and 44.5 seconds (range: 15-180), respectively. Evaluation prior to renal hilar clamping demonstrated the presence of blood flow in all 20 patients (100%) using the SUS and in 17 of 20 (85%) using the DP. Similarly, cessation of blood flow with clamping was documented in 100% of cases with SUS and 85% with DP. Persistent flow was detected by both SUS and DP in two patients requiring further dissection and reclamping. Then, both systems detected the absence of flow before tumor resection. With blood flow interruption confirmation, no patient had significant bleeding at the time of renal parenchymal transection. Intraoperative Doppler ultrasound technologies minimize the risk of significant bleeding during LPN. The DP is a small, simple, effective probe that can be used to assess blood flow interruption to the kidney during laparoscopic renal surgery.

First Results of the Land Atmosphere Feedback Experiment

NASA Astrophysics Data System (ADS)

Wulfmeyer, V.; Turner, D. D.

2017-12-01

The Land-Atmosphere Feedback Experiment (LAFE) deployed several state-of-the-art scanning lidar and remote sensing systems to the ARM SGP site during August 2017. A novel synergy of remote sensing systems was applied for simultaneous measurements of land-surface fluxes and horizontal and vertical transport processes in the atmospheric boundary layer (ABL). The impact of spatial inhomogeneities of the soil-vegetation continuum on LA feedback was studied using the scanning capability of the instrumentation as well as soil, vegetation, and surface flux measurements. The synergy of remote sensing and in-situ instruments consisted of three components: 1) The SGP water-vapor and temperature Raman lidar, the SGP Doppler lidar, the University of Hohenheim (UHOH) Doppler lidar, and the NCAR water-vapor DIAL to measure mean profiles and gradients of moisture, temperature, and horizontal wind. Due to their high vertical and temporal resolutions, also profiles of higher-order turbulent moments in the water vapor and wind fields as well as of profiles of the latent heat flux, the sensible heat flux, TKE, and momentum flux were observed. 2) A novel scanning lidar system synergy consisting of the NOAA High-Resolution Doppler lidar, the UHOH water-vapor differential absorption lidar, and the UHOH temperature rotational Raman lidar. These systems performed coordinated range-height indicator (RHI) scans from just above the canopy level to the lower troposphere including the interfacial layer at the ABL top. This component was augmented by three energy balance closure towers of NOAA and one EBC station of UHOH. 3) The University of Wisconsin SPARC and the University of Oklahoma CLAMPS systems operating two vertically pointing atmospheric emitted radiance interferometers and two Doppler lidar systems scanning cross track to the central RHI for determining the surface friction velocity and the horizontal variability of temperature, moisture, and wind. NOAA ARL also provided UAS and aircraft measurements (Navajo Piper) in accordance with the surface scans. Thus, both the variability of surface fluxes and CBL dynamics and thermodynamics over the SGP site was studied for the first time. This is essential for advanced observation and understanding of LA feedback. First results are presented at the conference.

Validation of simple indexes to assess insulin sensitivity during pregnancy in Wistar and Sprague-Dawley rats.

PubMed

Cacho, J; Sevillano, J; de Castro, J; Herrera, E; Ramos, M P

2008-11-01

Insulin resistance plays a role in the pathogenesis of diabetes, including gestational diabetes. The glucose clamp is considered the gold standard for determining in vivo insulin sensitivity, both in human and in animal models. However, the clamp is laborious, time consuming and, in animals, requires anesthesia and collection of multiple blood samples. In human studies, a number of simple indexes, derived from fasting glucose and insulin levels, have been obtained and validated against the glucose clamp. However, these indexes have not been validated in rats and their accuracy in predicting altered insulin sensitivity remains to be established. In the present study, we have evaluated whether indirect estimates based on fasting glucose and insulin levels are valid predictors of insulin sensitivity in nonpregnant and 20-day-pregnant Wistar and Sprague-Dawley rats. We have analyzed the homeostasis model assessment of insulin resistance (HOMA-IR), the quantitative insulin sensitivity check index (QUICKI), and the fasting glucose-to-insulin ratio (FGIR) by comparing them with the insulin sensitivity (SI(Clamp)) values obtained during the hyperinsulinemic-isoglycemic clamp. We have performed a calibration analysis to evaluate the ability of these indexes to accurately predict insulin sensitivity as determined by the reference glucose clamp. Finally, to assess the reliability of these indexes for the identification of animals with impaired insulin sensitivity, performance of the indexes was analyzed by receiver operating characteristic (ROC) curves in Wistar and Sprague-Dawley rats. We found that HOMA-IR, QUICKI, and FGIR correlated significantly with SI(Clamp), exhibited good sensitivity and specificity, accurately predicted SI(Clamp), and yielded lower insulin sensitivity in pregnant than in nonpregnant rats. Together, our data demonstrate that these indexes provide an easy and accurate measure of insulin sensitivity during pregnancy in the rat.

Different methods of hilar clamping during partial nephrectomy: Impact on renal function.

PubMed

Lee, Jeong Woo; Kim, Hwanik; Choo, Minsoo; Park, Yong Hyun; Ku, Ja Hyeon; Kim, Hyeon Hoe; Kwak, Cheol

2014-03-01

To evaluate the impact of different hilar clamping methods on changes in renal function after partial nephrectomy. We analyzed the clinical data of 369 patients who underwent partial nephrectomy for a single renal tumor of size ≤4.0 cm and a normal contralateral kidney. Patients were separated into three groups depending on hilar clamping method: non-clamping, cold ischemia and warm ischemia. Estimated glomerular filtration rate was examined at preoperative, nadir and 1 year postoperatively. Percent change in estimated glomerular filtration rate was used as the parameter to assess the renal functional outcome. Percent change in nadir estimated glomerular filtration rate in the non-clamping group was significantly less compared with the cold ischemia and warm ischemia groups (P < 0.001). However, no significant differences among the groups were noted in percent change of estimated glomerular filtration rate at 1 year (P = 0.348). The cold ischemia group had a similar serial change of postoperative renal function compared with the warm ischemia group. Percent change in 1-year estimated glomerular filtration rate increased with increasing ischemia time in the cold ischemia (P for trend = 0.073) and warm ischemia groups (P for trend = 0.010). On multivariate analysis, hilar clamping (both warm ischemia and cold ischemia) were significantly associated with percent change in nadir estimated glomerular filtration rate, but not in 1-year estimated glomerular filtration rate. Non-clamping partial nephrectomy results in a lower percent change in nadir estimated glomerular filtration rate, whereas it carries an estimated glomerular filtration rate change at 1 year that is similar to partial nephrectomy with cold ischemia and warm ischemia. Cold ischemia and warm ischemia provide a similar effect on renal function. Therefore, when hilar clamping is required, minimization of ischemia time is necessary. © 2013 The Japanese Urological Association.

Crystal structure of the DNA polymerase III β subunit (β-clamp) from the extremophile Deinococcus radiodurans.

PubMed

Niiranen, Laila; Lian, Kjersti; Johnson, Kenneth A; Moe, Elin

2015-02-27

Deinococcus radiodurans is an extremely radiation and desiccation resistant bacterium which can tolerate radiation doses up to 5,000 Grays without losing viability. We are studying the role of DNA repair and replication proteins for this unusual phenotype by a structural biology approach. The DNA polymerase III β subunit (β-clamp) acts as a sliding clamp on DNA, promoting the binding and processivity of many DNA-acting proteins, and here we report the crystal structure of D. radiodurans β-clamp (Drβ-clamp) at 2.0 Å resolution. The sequence verification process revealed that at the time of the study the gene encoding Drβ-clamp was wrongly annotated in the genome database, encoding a protein of 393 instead of 362 amino acids. The short protein was successfully expressed, purified and used for crystallisation purposes in complex with Cy5-labeled DNA. The structure, which was obtained from blue crystals, shows a typical ring-shaped bacterial β-clamp formed of two monomers, each with three domains of identical topology, but with no visible DNA in electron density. A visualisation of the electrostatic surface potential reveals a highly negatively charged outer surface while the inner surface and the dimer forming interface have a more even charge distribution. The structure of Drβ-clamp was determined to 2.0 Å resolution and shows an evenly distributed electrostatic surface charge on the DNA interacting side. We hypothesise that this charge distribution may facilitate efficient movement on encircled DNA and help ensure efficient DNA metabolism in D. radiodurans upon exposure to high doses of ionizing irradiation or desiccation.

Safety evaluation of large external fixation clamps and frames in a magnetic resonance environment.

PubMed

Luechinger, Roger; Boesiger, Peter; Disegi, John A

2007-07-01

Large orthopedic external fixation clamps and related components were evaluated for force, torque, and heating response when subjected to the strong electromagnetic fields of magnetic-resonance (MR) imaging devices. Forces induced by a 3-Tesla (T) MR scanner were compiled for newly designed nonmagnetic clamps and older clamps that contained ferromagnetic components. Heating trials were performed in a 1.5 and in a 3 T MR scanner with two assembled external fixation frames. Forces of the newly designed clamps were more than a factor 2 lower as the gravitational force on the device whereas, magnetic forces on the older devices showed over 10 times the force induced by earth acceleration of gravity. No torque effects could be found for the newly designed clamps. Temperature measurements at the tips of Schanz screws in the 1.5 T MR scanner showed a rise of 0.7 degrees C for a pelvic frame and of 2.1 degrees C for a diamond knee bridge frame when normalized to a specific absorption rate (SAR) of 2 W/kg. The normalized temperature increases in the 3 T MR scanner were 0.9 degrees C for the pelvic frame and 1.1 degrees C for the knee bridge frame. Large external fixation frames assembled with the newly designed clamps (390 Series Clamps), carbon fiber reinforced rods, and implant quality 316L stainless steel Schanz screws met prevailing force and torque limits when tested in a 3-T field, and demonstrated temperature increase that met IEC-60601 guidelines for extremities. The influence of frame-induced eddy currents on the risk of peripheral nerve stimulation was not investigated. Copyright 2006 Wiley Periodicals, Inc.

Perioperative management of calves undergoing implantation of a left ventricular assist device.

PubMed

Wilson, D V; Kantrowitz, A; Pacholewicz, J; Salat, O; Paules, B R; Zhou, Y; Dawe, E J

2000-01-01

To describe perioperative management of calves that underwent left lateral thoracotomy, aortic cross-clamping, partial left heart bypass and implantation of a left ventricular assist device. A total of 43 healthy castrated male calves, weighing 121 +/- 24 kg. Diazepam (mean +/- SD, 0.26 +/- 0.07 mg/kg), ketamine (5.9 +/- 2.17 mg/kg) and isoflurane were used in the anesthetic management of calves undergoing implantation of a left ventricular assist device in the descending thoracic aorta. Other adjunctive agents administered were fentanyl (11 +/- 5.4 microg/kg), lidocaine (4.9 +/- 3.19 mg/kg), bupivacaine (0.75%) and butorphanol (0.49 +/- 0.13 mg/kg). None of the calves regurgitated at induction or during intubation. A tube was used to drain the rumen and prevent bloat during the procedure. Partial left heart bypass was used to perfuse the caudal half of the body during the period of aortic cross clamp and device implantation. Initial mean systemic blood pressure was 96 +/- 25 mm Hg, and pressures measured in the auricular artery increased during aortic cross-clamping and bypass. Vasoconstrictor therapy was required to treat caudal arterial hypotension during the procedure in 9 calves. Mean systemic arterial pressures returned to baseline values by the end of the anesthetic period. Initial mean pulmonary arterial pressures (PAP) were 22 +/- 3 mm Hg. A significant but transient increase in pulmonary arterial pressure occurred after both heparin and protamine administration. The described anesthetic protocol was effective for thoracotomy and implantation of an intra-aortic left ventricular assist device in normal calves. Partial left ventricular bypass was a useful adjunct during the period of aortic cross clamp. The doses of heparin and protamine administered were effective. Responsibility to monitor oxygenation of the cranial half of the animal continues during the bypass period as hypoxemia due to pulmonary dysfunction will not be detected by the perfusionist.

Study of clamping-induced deformations on SR optics by means of LTP

NASA Astrophysics Data System (ADS)

Cocco, Daniele; Sostero, Giovanni; Zangrando, Marco

2001-01-01

With the advent of third generation synchrotron radiation sources, more flux was available for the experimentalist. At the same time, the request in term of spot dimension and energy resolution rapidly increased. For this reason, opticians try to design beamlines with higher and higher performances. To this end the shape of every optical component of a beamline is specified to have very tight constrains, because every small figure error produces a sudden reduction in terms of the overall performance. Nevertheless, the necessity to positioning and cooling the components implies the presence of a safe clamping system which unavoidably would modifies the shape of the component, causing possible reduction of resolving power or increasing the spot dimension. Thus it is not sufficient to measure accurately the slope or the profile of a mirror in laboratory before the mounting, but it is useful to test it also after this procedure. We, at ELETTRA, have measured by means of a modified version of the LTP II (Long Trace Profiler) several mirrors and gratings before and after their clamping, in order to estimate the effect of the holder on the final performances of the beamlines. Since our LTP II measures directly the local slope of the surface under test with a repeatability better than 0.02 arcsec on a 1 meter long optical surface, it is very easy to single out any small distortion of the tangential profile introduced by the mounting system. Different kinds of supports for both small and large optical elements, were taken into consideration and the effect of the deformation induced by them on the beamline performance was simulated and will be presented here together with the results of each measurements. The results give us a way to select properly the kind of clamping and invite the opticians to try to take into consideration also this effect before designing a complex beamline.

Structural basis of human PCNA sliding on DNA

NASA Astrophysics Data System (ADS)

de March, Matteo; Merino, Nekane; Barrera-Vilarmau, Susana; Crehuet, Ramon; Onesti, Silvia; Blanco, Francisco J.; de Biasio, Alfredo

2017-01-01

Sliding clamps encircle DNA and tether polymerases and other factors to the genomic template. However, the molecular mechanism of clamp sliding on DNA is unknown. Using crystallography, NMR and molecular dynamics simulations, here we show that the human clamp PCNA recognizes DNA through a double patch of basic residues within the ring channel, arranged in a right-hand spiral that matches the pitch of B-DNA. We propose that PCNA slides by tracking the DNA backbone via a `cogwheel' mechanism based on short-lived polar interactions, which keep the orientation of the clamp invariant relative to DNA. Mutation of residues at the PCNA-DNA interface has been shown to impair the initiation of DNA synthesis by polymerase δ (pol δ). Therefore, our findings suggest that a clamp correctly oriented on DNA is necessary for the assembly of a replication-competent PCNA-pol δ holoenzyme.

Management of umbilical cord clamping.

PubMed

Webbon, Lucy

2013-02-01

The Royal College of Midwives (RCM) has updated its third stage of labour guidelines (RCM 2012) to be clearly supportive of a delay in umbilical cord clamping, although specific guidance on timing is yet to be announced. It is therefore imperative that both midwives and student midwives understand and are able to integrate delaying into their practice, as well as communicating to women the benefits; only in this way can we give women fully informed choices on this aspect of care. The main benefit of delayed cord clamping is the protection it can provide in reducing childhood anaemia, which is a major issue, especially in poorer countries. A review of the evidence found no risks linked to delayed clamping, and no evidence that it cannot be used in combination with the administration of uterotonic drugs. Delayed cord clamping can be especially beneficial for pre term and compromised babies.

Theoretical investigation of gain-clamped semiconductor optical amplifiers using the amplified spontaneous emission compensating effect

NASA Astrophysics Data System (ADS)

Jia, Xin-Hong

2006-12-01

The theoretical model on gain-clamped semiconductor optical amplifiers (GC-SOAs) based on compensating light has been constructed. Using this model, the effects of insertion position and peak reflectivity of the fiber Bragg grating (FBG) on the gain clamping and noise figure (NF) characteristics of GC-SOA are analyzed. The results show that the effect of the FBG insertion position on gain clamping is slight, but the lower NF can be obtained for input FBG-type GC-SOA; when the FBG peak wavelength is designed to close the signal wavelength, the gain clamping and NF characteristics that can be reached are better. Further study shows that, with the increased peak reflectivity of the FBG, the critical input power is broadened and the gain tends to be varied slowly; the larger bias current is helpful to raise gain and decrease the noise figure but is harmful to a gain flatness characteristic.

Efficacy and safety of posteromedial translation for correction of thoracic curves in adolescent idiopathic scoliosis using a new connection to the spine: the Universal Clamp

PubMed Central

Mazda, Keyvan; Even, Julien; Lefevre, Yan; Fitoussi, Franck; Penneçot, Georges-François

2008-01-01

Correction of adolescent idiopathic scoliosis (AIS) has been reported with various systems. All-screw constructs are currently the most popular, but they have been associated with a significant decrease in thoracic kyphosis, with a potential risk of junctional kyphosis, not observed with hybrid constructs in the literature. In addition, it is important to weigh potential advantages of pedicle screw fixation against risks specific to its use. Because hybrid constructs are associated with a lower risk of complications and better sagittal correction than all-screw constructs, at present we use lumbar pedicle screws combined with a new sublaminar connection to the spine (Universal Clamps) at thoracic levels. The purpose of this study was to determine the efficacy and safety of the Universal Clamp (UC) posteromedial translation technique for correction of AIS. Seventy-five consecutive patients underwent posterior spinal fusion and hybrid instrumentation for progressive AIS. Correction was performed at the thoracic level using posteromedial translation. At the lumbar level, correction was performed using in situ contouring and compression/distractions maneuvers. A minimum 2-year follow-up was required. Medical data and radiographs were prospectively analyzed and compared using a paired t test. The average age at surgery was 15 years and 4 months (±19 months). The average number of levels fused was 12 ± 1.6. The mean follow-up was 30 ± 5 months. The average preoperative Cobb angle of the major curve was 60° ± 20°. The immediate postoperative major curve correction averaged 66 ± 13%. The average loss of correction of the major curve between the early postoperative assessment and latest follow-up was 3.5° ± 1.4°. The mean Cincinnati correction index was 1.7 ± 0.8 postoperatively, and 1.57 ± 1 at last follow up. The mean rotation of the apical vertebra was corrected from 23.3° ± 9° preoperatively to 7.3° ± 5° at last follow up (69% improvement, P < 0.0001). In the sagittal plane, the mean thoracic kyphosis improved from 23.8° ± 14.2° preoperatively to 32.3° ± 7.3° at last follow up. For the 68 patients who had a normokyphotic or a hypokyphotic sagittal modifier, thoracic kyphosis increased from 20.5° ± 9.9° to 31.8° ± 7.4°, corresponding to a mean kyphosis correction of 55% at last follow up. No intraoperative complication occurred and none of the patients developed proximal junctional kyphosis during the follow up. The principal limitation of the UC technique was the rate of proximal posterior prominence (14.6%), leading us to recommend the use of conventional claws at the upper extremity of the construct. The technique was safe, and reduced operative time, radiation exposure, and blood loss. While achieving correction of deformity in the coronal and axial planes equivalent to the best reported results of all-screw or previous hybrid constructs, the UC hybrid technique appears to provide superior correction in the sagittal plane. The excellent outcome in all three planes was maintained at 2 year follow up. PMID:19089466

The Nano-Patch-Clamp Array: Microfabricated Glass Chips for High-Throughput Electrophysiology

NASA Astrophysics Data System (ADS)

Fertig, Niels

2003-03-01

Electrophysiology (i.e. patch clamping) remains the gold standard for pharmacological testing of putative ion channel active drugs (ICADs), but suffers from low throughput. A new ion channel screening technology based on microfabricated glass chip devices will be presented. The glass chips contain very fine apertures, which are used for whole-cell voltage clamp recordings as well as single channel recordings from mammalian cell lines. Chips containing multiple patch clamp wells will be used in a first bench-top device, which will allow perfusion and electrical readout of each well. This scalable technology will allow for automated, rapid and parallel screening on ion channel drug targets.

Surface characterization of selected LDEF tray clamps

NASA Technical Reports Server (NTRS)

Cromer, T. F.; Grammer, H. L.; Wightman, J. P.; Young, Philip R.; Slemp, Wayne S.

1993-01-01

The surface characterization of chromic acid anodized 6061-T6 aluminum alloy tray clamps has shown differences in surface chemistry depending upon the position on the Long Duration Exposure Facility (LDEF). Water contact angle results showed no changes in wettability of the tray clamps. The overall surface topography of the control, trailing edge(E3) and leading edge(D9) samples was similar. The thickness of the aluminum oxide layer for all samples determined by Auger depth profiling was less than one micron. X-ray photoelectron spectroscopy (XPS) analysis of the tray clamps showed significant differences in the surface composition. Carbon and silicon containing compounds were the primary contaminants detected.

Nocturnal Boundary-Layer Phenomena Observed at a Complex Site During the Perdigão Experiment

NASA Astrophysics Data System (ADS)

Bell, T.; Klein, P. M.; Smith, E.; Gebauer, J.; Turner, D. D.

2017-12-01

The Perdigão Field Experiment set out to study atmospheric flows in complex terrain and to collect a high-quality dataset for the validation of meso- and micro-scale models. An Intensive Observation Period (IOP) was conducted from May 1, 2017 through June 15, 2017 where a multitude of instruments were deployed in and around two nearly parallel ridges. The Collaborative Lower Atmospheric Mobile Profiling System (CLAMPS) was deployed and operated in the valley between the ridges. The CLAMPS facility, which was developed as a joint effort between the School of Meteorology at OU and NOAA's National Severe Storms Laboratory (NSSL), takes advantage of a microwave radiometer (MWR), an atmospheric emitted radiance interferometer (AERI), and a scanning doppler Lidar to profile the boundary layer with a high temporal and spatial resolution. Optimized Lidar scanning strategies and joint retrievals for the MWR and ARI data provide detailed information about the wind, turbulence and thermodynamic structure from the surface up to 1000 m AGL on most nights; sometimes the max height is even higher. Over the course of the IOP, CLAMPS observed many different phenomena. During some nights, when stronger background prevailed and was directed perpendicular to the valley, waves were observed at the ridges and in the valley. At the same time, radiational cooling led to drainage flows in the valley, particularly during nights when the mesoscale forcing was weak. At first, CLAMPS profile observations and data collected with radiosondes released at a near-by site are compared to assess the data quality. The radiosonde observations are also being used to document and classify the upper-level flow during the IOP. Additionally, CLAMPS data from a few selected nights will be presented and analyzed in terms of turbulence and its impact on mixing inside and above the valley. June 1-2 represents a good base-state case. Winds at ridge height were generally less than 5ms-1 after 0Z and valley flows were observed by CLAMPS. On May 15-16, a narrow 10ms-1 jet was present near ridge height and a wave formed in the valley overnight. On May 21-22, another 10ms-1 jet was observed, though flow in the valley was very different. Finally, the impacts of the different flow phenomena on the turbulence structure and atmospheric stability throughout the night will be discussed.

Analysis of the Nova Stat Strip® Glucose Meter for Real-Time Blood Glucose Determinations During Glucose Clamp Studies: “Don't Swap Horses in Midstream”

PubMed Central

Heinemann, Lutz

2010-01-01

Proper performance of glucose clamps is critically dependent on reliable blood glucose (BG) measurements. A number of requirements have to be fulfilled by a system that aims to replace the laboratory devices that are currently in use. Many more aspects need to be taken into account besides the accuracy of BG measurement. It might very well be that the BG meter studied by Rabiee and colleagues in this issue of Journal of Diabetes Science and Technology fulfills most or all of such requirements; however, these aspects have to be tested more thoroughly before one switches from an established measurement method to the Nova Stat Strip® glucometer. PMID:20920441

The acoustic power of a vibrating clamped circular plate revisited in the wide low frequency range using expansion into the radial polynomials.

PubMed

Rdzanek, Wojciech P

2016-06-01

This study deals with the classical problem of sound radiation of an excited clamped circular plate embedded into a flat rigid baffle. The system of the two coupled differential equations is solved, one for the excited and damped vibrations of the plate and the other one-the Helmholtz equation. An approach using the expansion into radial polynomials leads to results for the modal impedance coefficients useful for a comprehensive numerical analysis of sound radiation. The results obtained are accurate and efficient in a wide low frequency range and can easily be adopted for a simply supported circular plate. The fluid loading is included providing accurate results in resonance.

Real-Time linux dynamic clamp: a fast and flexible way to construct virtual ion channels in living cells.

PubMed

Dorval, A D; Christini, D J; White, J A

2001-10-01

We describe a system for real-time control of biological and other experiments. This device, based around the Real-Time Linux operating system, was tested specifically in the context of dynamic clamping, a demanding real-time task in which a computational system mimics the effects of nonlinear membrane conductances in living cells. The system is fast enough to represent dozens of nonlinear conductances in real time at clock rates well above 10 kHz. Conductances can be represented in deterministic form, or more accurately as discrete collections of stochastically gating ion channels. Tests were performed using a variety of complex models of nonlinear membrane mechanisms in excitable cells, including simulations of spatially extended excitable structures, and multiple interacting cells. Only in extreme cases does the computational load interfere with high-speed "hard" real-time processing (i.e., real-time processing that never falters). Freely available on the worldwide web, this experimental control system combines good performance. immense flexibility, low cost, and reasonable ease of use. It is easily adapted to any task involving real-time control, and excels in particular for applications requiring complex control algorithms that must operate at speeds over 1 kHz.

Characterization of bulbospongiosus muscle reflexes activated by urethral distension in male rats.

PubMed

Tanahashi, Masayuki; Karicheti, Venkateswarlu; Thor, Karl B; Marson, Lesley

2012-10-01

The urethrogenital reflex (UGR) is used as a surrogate model of the autonomic and somatic nerve and muscle activity that accompanies ejaculation. The UGR is evoked by distension of the urethra and activation of penile afferents. The current study compares two methods of elevating urethral intraluminal pressure in spinalized, anesthetized male Sprague-Dawley rats (n = 60). The first method, penile extension UGR, involves extracting the penis from the foreskin, so that urethral pressure rises due to a natural anatomical flexure in the penis. The second method, penile clamping UGR, involves penile extension UGR with the addition of clamping of the glans penis. Groups of animals were prepared that either received no additional treatment, surgical shams, or received bilateral nerve cuts (4 nerve cut groups): either the pudendal sensory nerve branch (SbPN), the pelvic nerves, the hypogastric nerves, or all three nerves. Penile clamping UGR was characterized by multiple bursts, monitored by electromyography (EMG) of the bulbospongiosus muscle (BSM) accompanied by elevations in urethral pressure. The penile clamping UGR activity declined across multiple trials and eventually resulted in only a single BSM burst, indicating desensitization. In contrast, the penile extension UGR, without penile clamping, evoked only a single BSM EMG burst that showed no desensitization. Thus, the UGR is composed of two BSM patterns: an initial single burst, termed urethrobulbospongiosus (UBS) reflex and a subsequent multiple bursting pattern (termed ejaculation-like response, ELR) that was only induced with penile clamping urethral occlusion. Transection of the SbPN eliminated the ELR in the penile clamping model, but the single UBS reflex remained in both the clamping and extension models. Pelvic nerve (PelN) transection increased the threshold for inducing BSM activation with both methods of occlusion but actually unmasked an ELR in the penile extension method. Hypogastric nerve (HgN) cuts did not significantly alter any parameter. Transection of all three nerves eliminated BSM activation completely. In conclusion, penile clamping occlusion recruits penile and urethral primary afferent fibers that are necessary for an ELR. Urethral distension without significant penile afferent activation recruits urethral primary afferent fibers carried in either the pelvic or pudendal nerve that are necessary for the single-burst UBS reflex.

Automated Electrophysiology Makes the Pace for Cardiac Ion Channel Safety Screening

PubMed Central

Möller, Clemens; Witchel, Harry

2011-01-01

The field of automated patch-clamp electrophysiology has emerged from the tension between the pharmaceutical industry’s need for high-throughput compound screening versus its need to be conservative due to regulatory requirements. On the one hand, hERG channel screening was increasingly requested for new chemical entities, as the correlation between blockade of the ion channel coded by hERG and torsades de pointes cardiac arrhythmia gained increasing attention. On the other hand, manual patch-clamping, typically quoted as the “gold-standard” for understanding ion channel function and modulation, was far too slow (and, consequently, too expensive) for keeping pace with the numbers of compounds submitted for hERG channel investigations from pharmaceutical R&D departments. In consequence it became more common for some pharmaceutical companies to outsource safety pharmacological investigations, with a focus on hERG channel interactions. This outsourcing has allowed those pharmaceutical companies to build up operational flexibility and greater independence from internal resources, and allowed them to obtain access to the latest technological developments that emerged in automated patch-clamp electrophysiology – much of which arose in specialized biotech companies. Assays for nearly all major cardiac ion channels are now available by automated patch-clamping using heterologous expression systems, and recently, automated action potential recordings from stem-cell derived cardiomyocytes have been demonstrated. Today, most of the large pharmaceutical companies have acquired automated electrophysiology robots and have established various automated cardiac ion channel safety screening assays on these, in addition to outsourcing parts of their needs for safety screening. PMID:22131974

Acute Effects of Oral Dehydroepiandrosterone on Counterregulatory Responses During Repeated Hypoglycemia in Healthy Humans

PubMed Central

Mikeladze, Maia; Hedrington, Maka S.; Joy, Nino; Tate, Donna B.; Younk, Lisa M.; Davis, Ian

2016-01-01

We tested the hypothesis that acute administration of oral dehydroepiandrosterone (DHEA) during episodes of repeated hypoglycemia can prevent the development of hypoglycemia-associated neuroendocrine and autonomic failure in healthy humans. Twenty-seven individuals (16 men, 11 women) participated in two separate randomized, single-blind, 2-day protocols. Day 1 consisted of morning and afternoon 2-h hypoglycemic clamps (2.9 mmol/L) with 800 mg of DHEA or placebo administered before each clamp. Day 2 consisted of a single 2-h hypoglycemic clamp (2.9 mmol/L) following either DHEA (1,600 mg) or placebo. A 3-tritiated glucose was used to determine glucose kinetics during hypoglycemia on day 2. Antecedent hypoglycemia with placebo resulted in significant reductions of epinephrine, norepinephrine, glucagon, growth hormone, cortisol, endogenous glucose production, and lipolytic and symptom responses. During hypoglycemia on day 2, DHEA prevented blunting of all neuroendocrine, autonomic nervous system (ANS), metabolic, and symptom counterregulatory responses following hypoglycemia on day 1. In summary, DHEA can acutely preserve a wide range of key neuroendocrine, ANS, and metabolic counterregulatory homeostatic responses during repeated hypoglycemia. We conclude that DHEA may have acute effects to protect against hypoglycemia-associated neuroendocrine and autonomic failure in healthy humans. PMID:27486235

DMA Modulus as a Screening Parameter for Compatibility of Polymeric Containment Materials with Various Solutions for use in Space Shuttle Microgravity Protein Crystal Growth (PCG) Experiments

NASA Technical Reports Server (NTRS)

Wingard, Charles Doug; Munafo, Paul M. (Technical Monitor)

2002-01-01

Protein crystals are grown in microgravity experiments inside the Space Shuttle during orbit. Such crystals are basically grown in a five-component system containing a salt, buffer, polymer, organic and water. During these experiments, a number of different polymeric containment materials must be compatible with up to hundreds of different PCG solutions in various concentrations for durations up to 180 days. When such compatibility experiments are performed at NASA/MSFC (Marshall Space Flight Center) simultaneously on containment material samples immersed in various solutions in vials, the samples are rather small out of necessity. DMA4 modulus was often used as the primary screening parameter for such small samples as a pass/fail criterion for incompatibility issues. In particular, the TA Instruments DMA 2980 film tension clamp was used to test rubber O-rings as small in I.D. as 0.091 in. by cutting through the cross-section at one place, then clamping the stretched linear cord stock at each end. The film tension clamp was also used to successfully test short length samples of medical/surgical grade tubing with an O.D. of 0.125 in.

Product Development and Cost Analysis of Fabricating the Prototype of Roller Clamp in Intravenous (I.V) Tubing Medical Devices using Fused Deposition Modeling (FDM) Technology

NASA Astrophysics Data System (ADS)

Way, Yusoff

2018-01-01

The main aim of this research is to develop a new prototype and to conduct cost analysis of the existing roller clamp which is one of parts attached to Intravenous (I.V) Tubing used in Intravenous therapy medical device. Before proceed with the process to manufacture the final product using Fused Deposition Modeling (FDM) Technology, the data collected from survey were analyzed using Product Design Specifications approach. Selected concept has been proven to have better quality, functions and criteria compared to the existing roller clamp and the cost analysis of fabricating the roller clamp prototype was calculated.

Transport systems of Ventricaria ventricosa: asymmetry of the hyper- and hypotonic regulation mechanisms.

PubMed

Bisson, M A; Beilby, M J

2008-01-01

Hyper- and hypotonic stresses elicit apparently symmetrical responses in the alga Ventricaria. With hypertonic stress, membrane potential difference (PD) between the vacuole and the external medium becomes more positive, conductance at positive PDs (Gmpos) increases and KCl is actively taken up to increase turgor. With hypotonic stress, the membrane PD becomes more negative, conductance at negative PDs (Gmneg) increases and KCl is lost to decrease turgor. We used inhibitors that affect active transport to determine whether agents that inhibit the K(+) pump and hypertonic regulation also inhibit hypotonic regulatory responses. Cells whose turgor pressure was held low by the pressure probe (turgor-clamped) exhibited the same response as cells challenged by hyperosmotic medium, although the response was maintained longer than in osmotically challenged cells, which regulate turgor. The role of active K(+) transport was confirmed by the effects of decreased light, dichlorophenyldimethyl urea and diethylstilbestrol, which induced a uniformly low conductance (quiet state). Cells clamped to high turgor exhibited the same response as cells challenged by hypo-osmotic medium, but the response was similarly transient, making effects of inhibitors hard to determine. Unlike clamped cells, cells challenged by hypo-osmotic medium responded to inhibitors with rapid, transient, negative-going PDs, with decreased Gmneg and increased Gmpos (linearized I-V), achieving the quiet state as PD recovered. These changes are different from those exerted on the pump state, indicating that different transport systems are responsible for turgor regulation in the two cases.

Enhanced strain effect of aged acceptor-doped BaTiO3 ceramics with clamping domain structures

NASA Astrophysics Data System (ADS)

Wang, Lei; Zhou, Zhiyong; Zhao, Xiaobo; Liu, Zhen; Liang, Ruihong; Dong, Xianlin

2017-03-01

A clamping domain structure is proposed to improve the amount of non-180° domain switching in BaTiO3 based piezoelectric ceramics. Experimental results show a large unipolar strain of 0.23% at 5 kV/mm in aged 0.5 mol. % Mn doped BaTiO3 ceramics with clamping domain structures, and the normalized strain (d33*= Smax/Emax) reaches 600 pm/V at low electric fields of 2 or 3 kV/mm. In contrast, pure BaTiO3 ceramics with clamping domain structures exhibit no clear polarization constriction or strain enhancement at 3 kV/mm. Electron paramagnetic resonance spectra verify the existence of titanium vacancies, Mn2+ and Mn4+, in 0.5 mol. % Mn doped BaTiO3 ceramics. These results indicate that the enhanced strain effect can be attributed to the combined effect of the clamping domain structure and stabilization of defect dipoles. This method provides a general way to obtain large strain in ferroelectrics.

Service equipment for use in hostile environments

NASA Technical Reports Server (NTRS)

Dolce, James L. (Inventor); Gordon, Andrew L. (Inventor)

1994-01-01

Service equipment for use in hostile environments includes a detachable service unit secured to a stationary service unit. The detachable service unit includes a housing with an exterior plate, a power control interface for connection to an exterior power source, locating pins located in said exterior plate, an electrical connector in the exterior plate electrically coupled to said power control interface, and a pair of clamping receptacles formed in the exterior plate and located on adjacent opposite edges of the exterior plate. The stationary unit includes an electrical connector for connection to the electrical connector of the detachable service unit, a clamping apparatus for clamping and unclamping the detachable service unit from the stationary unit, a base clamp assembly for mounting the clamping apparatus onto the stationary unit, and locating pin holes for receiving the locating pins and aligning the detachable service unit onto the stationary unit. The detachable service unit and stationary unit have mating scalloped faces which aid in alignment and provide a mechanism for heat dissipation.

Conformational analysis of processivity clamps in solution demonstrates that tertiary structure does not correlate with protein dynamics.

PubMed

Fang, Jing; Nevin, Philip; Kairys, Visvaldas; Venclovas, Česlovas; Engen, John R; Beuning, Penny J

2014-04-08

The relationship between protein sequence, structure, and dynamics has been elusive. Here, we report a comprehensive analysis using an in-solution experimental approach to study how the conservation of tertiary structure correlates with protein dynamics. Hydrogen exchange measurements of eight processivity clamp proteins from different species revealed that, despite highly similar three-dimensional structures, clamp proteins display a wide range of dynamic behavior. Differences were apparent both for structurally similar domains within proteins and for corresponding domains of different proteins. Several of the clamps contained regions that underwent local unfolding with different half-lives. We also observed a conserved pattern of alternating dynamics of the α helices lining the inner pore of the clamps as well as a correlation between dynamics and the number of salt bridges in these α helices. Our observations reveal that tertiary structure and dynamics are not directly correlated and that primary structure plays an important role in dynamics. Copyright © 2014 Elsevier Ltd. All rights reserved.

Influence of clamp-up force on the strength of bolted composite joints

NASA Astrophysics Data System (ADS)

Horn, Walter J.; Schmitt, Ron R.

1994-03-01

Composite materials offer the potential for a reduction in the number of individual parts and joints in a structure because large one-piece components can replace multipart assemblies. Nevertheless, there are many situations where composite parts must be joined and often mechanical fasteners provide the only practical method of joining those parts. The long-term strength of mechanically fastened joints of composite members can be directly affected by the clamp-up force of the fastener and thus perhaps by the relaxation of this force due to the viscoelastic character of the composite materials of the joint. Methods for predicting the effect of bolt clamp-up force relaxation on the strength of mechanically fastened joints of thermoplastic composite materials were investigated during the present study. A test program, using two thermoplastic composite materials, was conducted to determine the influence of clamp-up force on joint strength, to measure the relaxation of the joint clamp-up force with time, and to measure the change of joint strength as a function of time.

Experimental and numerical analysis of clamped joints in front motorbike suspensions

NASA Astrophysics Data System (ADS)

Croccolo, D.; de Agostinis, M.; Vincenzi, N.

2010-06-01

Clamped joints are shaft-hub connections used, as an instance, in front motorbike suspensions to lock the steering plates with the legs and the legs with the wheel pin, by means of one or two bolts. The preloading force, produced during the tightening process, should be evaluated accurately, since it must lock safely the shaft, without overcoming the yielding point of the hub. Firstly, friction coefficients have been evaluated on “ad-hoc designed” specimens, by applying the Design of Experiment approach: the applied tightening torque has been precisely related to the imposed preloading force. Then, the tensile state of clamps have been evaluated both via FEM and by leveraging some design formulae proposed by the Authors as function of the preloading force and of the clamp geometry. Finally, the results have been compared to those given by some strain gauges applied on the tested clamps: the discrepancies between numerical analyses, the design formulae and the experimental results remains under a threshold of 10%.

The Promise of Microelectrode Array Approaches for Toxicity Testing: Examples with Neuroactive Chemicals

EPA Science Inventory

While high-throughput patch clamping formats provide rapid characterization of chemical effects on ion channel function and kinetics, the limitations of such systems often include the need for channel by channel characterization, requirements for transfected, rather than primary ...

Normal Modes of Vibration of the PHALANX Gun

DTIC Science & Technology

1993-06-01

Clamps Bricks, Thin Shells, Rigid Elements Mid-Barrel Clamps Bricks, Rigid Elements Barrels Beams with tubular cross-section Stub Rotor Bricks, Thin...Shells Rotor Bricks Needle Bearing Bricks, Springs Casing Thin Shells Thrust Bearing Bricks, Springs Recoil Adapters Bricks, Rigid Elements, Springs... rigid elements were used to connect the barrels to the clamps and stub rotor and the recoil adapter springs to 48 the gun body. "End release codes

Single mode variable-sensitivity fiber optic sensors

NASA Technical Reports Server (NTRS)

Murphy, K. A.; Fogg, B. R.; Gunther, M. F.; Claus, R. O.

1992-01-01

We review spatially-weighted optical fiber sensors that filter specific vibration modes from one dimensional beams placed in clamped-free and clamped-clamped configurations. The sensitivity of the sensor is varied along the length of the fiber by tapering circular-core, dual-mode optical fibers. Selective vibration mode suppression on the order of 10 dB was obtained. We describe experimental results and propose future extensions to single mode sensor applications.

Pitfalls during biomechanical testing - Evaluation of different fixation methods for measuring tendons endurance properties.

PubMed

Hangody, Gy; Pánics, G; Szebényi, G; Kiss, R; Hangody, L; Pap, K

2016-03-01

The goal of the study was to find a proper technique to fix tendon grafts into an INSTRON loading machine. From 8 human cadavers, 40 grafts were collected. We removed the bone-patella tendon-bone grafts, the semitendinosus and gracilis tendons, the quadriceps tendon-bone grafts, the Achilles tendons, and the peroneus longus tendons from each lower extremity. We tested the tendon grafts with five different types of fixation devices: surgical thread (Premicron 3), general mounting clamp, wire mesh, cement fixation, and a modified clamp for an INSTRON loading machine. The mean failure load in case of surgical thread fixation was (381N ± 26N). The results with the general clamp were (527N ± 45N). The wire meshes were more promising (750N ± 21N), but did not reach the outcomes we desired. Easy slippages of the ends of the tendons from the cement encasements were observed (253N ± 18N). We then began to use Shi's clamp that could produce 977N ± 416N peak force. We combined Shi's clamp with freezing of the graft and the rupture of the tendon itself demonstrated an average force of 2198 N ± 773N. We determined that our modified frozen clamp fixed the specimens against high tensile forces.

HTS techniques for patch clamp-based ion channel screening - advances and economy.

PubMed

Farre, Cecilia; Fertig, Niels

2012-06-01

Ten years ago, the first publication appeared showing patch clamp recordings performed on a planar glass chip instead of using a conventional patch clamp pipette. "Going planar" proved to revolutionize ion channel drug screening as we know it, by allowing high quality measurements of ion channels and their effectors at a higher throughput and at the same time de-skilling the highly laborious technique. Over the years, platforms evolved in response to user requirements regarding experimental features, data handling plus storage, and suitable target diversity. This article gives a snapshot image of patch clamp-based ion channel screening with focus on platforms developed to meet requirements of high-throughput screening environments. The commercially available platforms are described, along with their benefits and drawbacks in ion channel drug screening. Automated patch clamp (APC) platforms allow faster investigation of a larger number of ion channel active compounds or cell clones than previously possible. Since patch clamp is the only method allowing direct, real-time measurements of ion channel activity, APC holds the promise of picking up high quality leads, where they otherwise would have been overseen using indirect methods. In addition, drug candidate safety profiling can be performed earlier in the drug discovery process, avoiding late-phase compound withdrawal due to safety liability issues, which is highly costly and inefficient.

Ion channel drug discovery and research: the automated Nano-Patch-Clamp technology.

PubMed

Brueggemann, A; George, M; Klau, M; Beckler, M; Steindl, J; Behrends, J C; Fertig, N

2004-01-01

Unlike the genomics revolution, which was largely enabled by a single technological advance (high throughput sequencing), rapid advancement in proteomics will require a broader effort to increase the throughput of a number of key tools for functional analysis of different types of proteins. In the case of ion channels -a class of (membrane) proteins of great physiological importance and potential as drug targets- the lack of adequate assay technologies is felt particularly strongly. The available, indirect, high throughput screening methods for ion channels clearly generate insufficient information. The best technology to study ion channel function and screen for compound interaction is the patch clamp technique, but patch clamping suffers from low throughput, which is not acceptable for drug screening. A first step towards a solution is presented here. The nano patch clamp technology, which is based on a planar, microstructured glass chip, enables automatic whole cell patch clamp measurements. The Port-a-Patch is an automated electrophysiology workstation, which uses planar patch clamp chips. This approach enables high quality and high content ion channel and compound evaluation on a one-cell-at-a-time basis. The presented automation of the patch process and its scalability to an array format are the prerequisites for any higher throughput electrophysiology instruments.

The structure of a ring-opened proliferating cell nuclear antigen-replication factor C complex revealed by fluorescence energy transfer.

PubMed

Zhuang, Zhihao; Yoder, Bonita L; Burgers, Peter M J; Benkovic, Stephen J

2006-02-21

Numerous proteins that function in DNA metabolic pathways are known to interact with the proliferating cell nuclear antigen (PCNA). The important function of PCNA in stimulating various cellular activities requires its topological linkage with DNA. Loading of the circular PCNA onto duplex DNA requires the activity of a clamp-loader [replication factor C (RFC)] complex and the energy derived from ATP hydrolysis. The mechanistic and structural details regarding PCNA loading by the RFC complex are still developing. In particular, the positive identification of a long-hypothesized structure of an open clamp-RFC complex as an intermediate in loading has remained elusive. In this study, we capture an open yeast PCNA clamp in a complex with RFC through fluorescence energy transfer experiments. We also follow the topological transitions of PCNA in the various steps of the clamp-loading pathway through both steady-state and stopped-flow fluorescence studies. We find that ATP effectively drives the clamp-loading process to completion with the formation of the closed PCNA bound to DNA, whereas ATPgammaS cannot. The information derived from this work complements that obtained from previous structural and mechanistic studies and provides a more complete picture of a eukaryotic clamp-loading pathway using yeast as a paradigm.

Timing of cord clamping in very preterm infants: more evidence is needed.

PubMed

Tarnow-Mordi, William O; Duley, Lelia; Field, David; Marlow, Neil; Morris, Jonathan; Newnham, John; Paneth, Nigel; Soll, Roger F; Sweet, David

2014-08-01

In December 2012, the American College of Obstetricians and Gynecologists published a Committee Opinion entitled "Timing of umbilical cord clamping after birth." It stated that "evidence exists to support delayed cord clamping in preterm infants, when feasible. The single most important benefit for preterm infants is the possibility for a nearly 50% reduction in IVH." However, the Committee Opinion added that the ideal timing of umbilical cord clamping has yet to be determined and recommended that large clinical trials be conducted in the most preterm infants. Published randomized controlled trials include <200 infants of <30 weeks' gestation, with assessments of neurodevelopmental outcome in less than one-half of the children. This is a major gap in the evidence. Without reliable data from randomized controlled trials that optimally include childhood follow-up evaluations, we will not know whether delayed cord clamping may do more overall harm than good. Ongoing trials of delayed cord clamping plan to report childhood outcomes in >2000 additional very preterm infants. Current recommendations may need to change when these results become available. Greater international collaboration could accelerate resolution of whether this promising intervention will improve disability-free survival in about 1 million infants who will be born very preterm globally each year. Copyright © 2014 Mosby, Inc. All rights reserved.

Glomerular loss after arteriovenous and arterial clamping for renal warm ischemia in a swine model.

PubMed

Bechara, Gustavo Ruschi; Damasceno-Ferreira, José Aurelino; Abreu, Leonardo Albuquerque Dos Santos; Costa, Waldemar Silva; Sampaio, Francisco José Barcellos; Pereira-Sampaio, Marco Aurélio; Souza, Diogo Benchimol De

2016-11-01

To evaluate the glomerular loss after arteriovenous or arterial warm ischemia in a swine model. Twenty four pigs were divided into Group Sham (submitted to all surgical steps except the renal ischemia), Group AV (submitted to 30 minutes of warm ischemia by arteriovenous clamping of left kidney vessels), and Group A (submitted to 30 minutes of ischemia by arterial clamping). Right kidneys were used as controls. Weigh, volume, cortical volume, glomerular volumetric density (Vv[Glom]), volume-weighted glomerular volume (VWGV), and the total number of glomeruli were measured for each organ. Group AV showed a 24.5% reduction in its left kidney Vv[Glom] and a 25.4% reduction in the VWGV, when compared to the right kidney. Reductions were also observed when compared to kidneys of sham group. There was a reduction of 19.2% in the total number of glomeruli in AV kidneys. No difference was observed in any parameters analyzed on the left kidneys from group A. Renal warm ischemia of 30 minutes by arterial clamping did not caused significant glomerular damage, but arteriovenous clamping caused significant glomerular loss in a swine model. Clamping only the renal artery should be considered to minimize renal injury after partial nephrectomies.

Cerebral watershed infarcts may be induced by hemodynamic changes in blood flow.

PubMed

Shi, Jingfei; Meng, Ran; Konakondla, Sanjay; Ding, Yuchuan; Duan, Yunxia; Wu, Di; Wang, Bincheng; Luo, Yinghao; Ji, Xunming

2017-06-01

A watershed infarct is defined as an ischemic lesion at the border zones between territories of two major arteries. The pathogenesis of watershed infarcts, specifically whether they are caused by hemodynamic or embolic mechanisms, has long been debated. In this study, we aimed to examine whether watershed infarcts can be induced by altering the hemodynamic conditions in rats. In phase one, to determine the proper clamping duration for a reproducible infarct, 30 rats were equally divided into 5 subgroups and underwent bilateral common carotid artery (CCA) clamping for different durations (0.5, 1.0, 1.5, 2.0, and 3.0 hours). In phase two, to analyze the types of infarcts induced by bilateral CCA clamping, 40 rats were subjected to bilateral CCA clamping for 2 hours. As a control, 8 rats underwent all the operation procedures except bilateral CCA clamping. We performed 7.0T magnetic resonance imaging on the surviving rats on the second day to evaluate the extent of the infarcts. We further identified and examined the infarcts with brain slices stained using 2, 3, 5-triphenyltetrazolium chloride (TTC) on the third day. After 2 hours of bilateral CCA clamping, cerebral infarction occurred in 42% of surviving rats (13/31). The majority of the ischemic lesions were located in watershed regions of the brain, demonstrated by both MRI and TTC staining. Watershed infarcts were induced through changing hemodynamic conditions by bilateral CCA clamping in rats. This method may lead to the development of a reliable rodent model for watershed infarcts.

Patch-Clamp Recording from Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes: Improving Action Potential Characteristics through Dynamic Clamp

PubMed Central

Veerman, Christiaan C.; Zegers, Jan G.; Mengarelli, Isabella; Bezzina, Connie R.

2017-01-01

Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) hold great promise for studying inherited cardiac arrhythmias and developing drug therapies to treat such arrhythmias. Unfortunately, until now, action potential (AP) measurements in hiPSC-CMs have been hampered by the virtual absence of the inward rectifier potassium current (IK1) in hiPSC-CMs, resulting in spontaneous activity and altered function of various depolarising and repolarising membrane currents. We assessed whether AP measurements in “ventricular-like” and “atrial-like” hiPSC-CMs could be improved through a simple, highly reproducible dynamic clamp approach to provide these cells with a substantial IK1 (computed in real time according to the actual membrane potential and injected through the patch-clamp pipette). APs were measured at 1 Hz using perforated patch-clamp methodology, both in control cells and in cells treated with all-trans retinoic acid (RA) during the differentiation process to increase the number of cells with atrial-like APs. RA-treated hiPSC-CMs displayed shorter APs than control hiPSC-CMs and this phenotype became more prominent upon addition of synthetic IK1 through dynamic clamp. Furthermore, the variability of several AP parameters decreased upon IK1 injection. Computer simulations with models of ventricular-like and atrial-like hiPSC-CMs demonstrated the importance of selecting an appropriate synthetic IK1. In conclusion, the dynamic clamp-based approach of IK1 injection has broad applicability for detailed AP measurements in hiPSC-CMs. PMID:28867785

Rectal transection using a curved cutter stapler with an endo-Satinsky clamp during a laparoscopic low anterior resection.

PubMed

Hotta, Tsukasa; Takifuji, Katsunari; Yokoyama, Shozo; Matsuda, Kenji; Yamaue, Hiroki

2012-10-01

A new rectal transaction method was developed using a combination of the curved cutter stapler and endo-Satinsky clamp because of the difficulty in performing rectal transection in the narrow pelvic cavity. The endo-Satinsky clamp is inserted without a flexible trocar cannula by connecting the handle extra-abdominally with a shaft of the endo-Satinsky clamp through the left higher quadrant port via a retrograde course from a midline incision above the pubis symphysis. The endo-Satinsky clamp is used to clamp the rectal wall horizontally at the distal end of the tumor. The wrist of an elastic surgical glove fixed with the shaft of the curved cutter stapler is covered with a midline incision, and consequently, the stapler is inserted into the pelvic cavity. The curved head of the stapler is rotated to the left at the anal side of the endo-Satinsky clamp to insert the rectum between the jaws of the stapler. The stapler is closed and fired, and a rectal transection is thus performed with one firing using a single cartridge. This method was performed in 12 patients with rectal cancer. The median value and range of the tumor distance from the anal verge were 7.0 and 4.5-11.0 cm, respectively. The median duration of the operation was 252 min, and the median blood loss was 15 mL. Only one stapling cartridge was used for rectal transection in all cases, and no major complications were observed. We herein demonstrated a new transection method for rectal cancer.

Application of Fracture Mechanics to Specify the Proof Load Factor for Clamp Band Systems of Launch Vehicles

NASA Astrophysics Data System (ADS)

Singaravelu, J.; Sundaresan, S.; Nageswara Rao, B.

2013-04-01

This article presents a methodology for evaluation of the proof load factor (PLF) for clamp band system (CBS) made of M250 Maraging steel following fracture mechanics principles.CBS is most widely used as a structural element and as a separation system. Using Taguchi's design of experiments and the response surface method (RSM) the compact tension specimens were tested to establish an empirical relation for the failure load ( P max) in terms of the ultimate strength, width, thickness, and initial crack length. The test results of P max closely matched with the developed RSM empirical relation. Crack growth rates of the maraging steel in different environments were examined. Fracture strength (σf) of center surface cracks and through-crack tension specimens are evaluated utilizing the fracture toughness ( K IC). Stress induced in merman band at flight loading conditions is evaluated to estimate the higher load factor and PLF. Statistical safety factor and reliability assessments were made for the specified flaw sizes useful in the development of fracture control plan for CBS of launch vehicles.

Timing of umbilical cord-clamping and infant anaemia: the role of maternal anaemia.

PubMed

Blouin, Brittany; Penny, Mary E; Maheu-Giroux, Mathieu; Casapía, Martín; Aguilar, Eder; Silva, Hermánn; Creed-Kanashiro, Hilary M; Joseph, Serene A; Gagnon, Anita; Rahme, Elham; Gyorkos, Theresa W

2013-05-01

Evidence from randomized controlled trials has shown that delayed cord-clamping is beneficial to infant iron status. The role of maternal anaemia in this relationship, however, has not been established. To determine the effect of maternal anaemia at delivery on the association between timing of umbilical cord-clamping and infant anaemia at 4 and 8 months of age. A cohort of pregnant women admitted to the labour room of Hospital Iquitos (Iquitos, Peru) and their newborns were recruited into the study during two time periods (18 May to 3 June and 6-20 July 2009). Between the two recruitment periods, the hospital's policy changed from early to delayed umbilical cord-clamping. Maternal haemoglobin levels were measured before delivery, and the time between delivery and cord-clamping was recorded at delivery for the entire cohort. Mother-infant pairs were followed-up at 4 (n = 207) and 8 months (n = 184) post partum. Infant haemoglobin levels were measured at follow-up visits. Data were analysed using logistic regression models. The prevalence of maternal anaemia (Hb <11.0 g/dl) at delivery was 22%. Infant haemoglobin levels at 4 and 8 months of age were 10.4 g/dl and 10.3 g/dl, respectively. Infant haemoglobin levels did not differ significantly between infants born to anaemic mothers and those born to non-anaemic mothers at either 4 or 8 months of age. However, the association between the timing of cord-clamping and infant anaemia was modified by the mother's anaemia status. Significant benefits of delayed cord-clamping in preventing anaemia were found in infants born to anaemic mothers at both 4 months (aOR = 0.59, 95% CI 0.36-0.99) and 8 months (aOR = 0.38, 95% CI 0.19-0.76) of age. The study contributes additional evidence in support of delayed cord-clamping. This intervention is likely to have most public health impact in areas with a high prevalence of anaemia during pregnancy.

Biomechanical evaluation of a new fixation device for the thoracic spine.

PubMed

Hongo, Michio; Ilharreborde, Brice; Gay, Ralph E; Zhao, Chunfeng; Zhao, Kristin D; Berglund, Lawrence J; Zobitz, Mark; An, Kai-Nan

2009-08-01

The technology used in surgery for spinal deformity has progressed rapidly in recent years. Commonly used fixation techniques may include monofilament wires, sublaminar wires and cables, and pedicle screws. Unfortunately, neurological complications can occur with all of these, compromising the patients' health and quality of life. Recently, an alternative fixation technique using a metal clamp and polyester belt was developed to replace hooks and sublaminar wiring in scoliosis surgery. The goal of this study was to compare the pull-out strength of this new construct with sublaminar wiring, laminar hooks and pedicle screws. Forty thoracic vertebrae from five fresh frozen human thoracic spines (T5-12) were divided into five groups (8 per group), such that BMD values, pedicle diameter, and vertebral levels were equally distributed. They were then potted in polymethylmethacrylate and anchored with metal screws and polyethylene bands. One of five fixation methods was applied to the right side of the vertebra in each group: Pedicle screw, sublaminar belt with clamp, figure-8 belt with clamp, sublaminar wire, or laminar hook. Pull-out strength was then assessed using a custom jig in a servohydraulic tester. The mean failure load of the pedicle screw group was significantly larger than that of the figure-8 clamp (P = 0.001), sublaminar belt (0.0172), and sublaminar wire groups (P = 0.04) with no significant difference in pull-out strength between the latter three constructs. The most common mode of failure was the fracture of the pedicle. BMD was significantly correlated with failure load only in the figure-8 clamp and pedicle screw constructs. Only the pedicle screw had a statistically significant higher failure load than the sublaminar clamp. The sublaminar method of applying the belt and clamp device was superior to the figure-8 method. The sublaminar belt and clamp construct compared favorably to the traditional methods of sublaminar wires and laminar hooks, and should be considered as an alternative fixation device in the thoracic spine.

Biomechanical evaluation of a new fixation device for the thoracic spine

PubMed Central

Hongo, Michio; Ilharreborde, Brice; Zhao, Chunfeng; Zhao, Kristin D.; Berglund, Lawrence J.; Zobitz, Mark; An, Kai-Nan

2009-01-01

The technology used in surgery for spinal deformity has progressed rapidly in recent years. Commonly used fixation techniques may include monofilament wires, sublaminar wires and cables, and pedicle screws. Unfortunately, neurological complications can occur with all of these, compromising the patients’ health and quality of life. Recently, an alternative fixation technique using a metal clamp and polyester belt was developed to replace hooks and sublaminar wiring in scoliosis surgery. The goal of this study was to compare the pull-out strength of this new construct with sublaminar wiring, laminar hooks and pedicle screws. Forty thoracic vertebrae from five fresh frozen human thoracic spines (T5–12) were divided into five groups (8 per group), such that BMD values, pedicle diameter, and vertebral levels were equally distributed. They were then potted in polymethylmethacrylate and anchored with metal screws and polyethylene bands. One of five fixation methods was applied to the right side of the vertebra in each group: Pedicle screw, sublaminar belt with clamp, figure-8 belt with clamp, sublaminar wire, or laminar hook. Pull-out strength was then assessed using a custom jig in a servohydraulic tester. The mean failure load of the pedicle screw group was significantly larger than that of the figure-8 clamp (P = 0.001), sublaminar belt (0.0172), and sublaminar wire groups (P = 0.04) with no significant difference in pull-out strength between the latter three constructs. The most common mode of failure was the fracture of the pedicle. BMD was significantly correlated with failure load only in the figure-8 clamp and pedicle screw constructs. Only the pedicle screw had a statistically significant higher failure load than the sublaminar clamp. The sublaminar method of applying the belt and clamp device was superior to the figure-8 method. The sublaminar belt and clamp construct compared favorably to the traditional methods of sublaminar wires and laminar hooks, and should be considered as an alternative fixation device in the thoracic spine. PMID:19404687

Prototype space erectable radiator system ground test article development

NASA Technical Reports Server (NTRS)

Alario, Joseph P.

1988-01-01

A prototype heat rejecting system is being developed by NASA-JSC for possible space station applications. This modular system, the Space-Erectable Radiator System Ground Test Article (SERS-GTA) with high-capacity radiator panels, can be installed and replaced on-orbit. The design, fabrication and testing of a representative ground test article are discussed. Acceptance test data for the heat pipe radiator panel and the whiffletree clamping mechanism have been presented.

Control of a Vanadium Redox Battery and supercapacitor using a Three-Level Neutral Point Clamped converter

NASA Astrophysics Data System (ADS)

Etxeberria, A.; Vechiu, I.; Baudoin, S.; Camblong, H.; Kreckelbergh, S.

2014-02-01

The increasing use of distributed generators, which are mainly based on renewable sources, can create several issues in the operation of the electric grid. The microgrid is being analysed as a solution to the integration in the grid of the renewable sources at a high penetration level in a controlled way. The storage systems play a vital role in order to keep the energy and power balance of the microgrid. Due to the technical limitations of the currently available storage systems, it is necessary to use more than one storage technology to satisfy the requirements of the microgrid application. This work validates in simulations and experimentally the use of a Three-Level Neutral Point Clamped converter to control the power flow of a hybrid storage system formed by a SuperCapacitor and a Vanadium Redox Battery. The operation of the system is validated in two case studies in the experimental platform installed in ESTIA. The experimental results prove the validity of the proposed system as well as the designed control algorithm. The good agreement among experimental and simulation results also validates the simulation model, that can therefore be used to analyse the operation of the system in different case studies.

Design of a Vertical Composite Thin Film System with Ultralow Leakage To Yield Large Converse Magnetoelectric Effect.

PubMed

Wu, Rui; Kursumovic, Ahmed; Gao, Xingyao; Yun, Chao; Vickers, Mary E; Wang, Haiyan; Cho, Seungho; MacManus-Driscoll, Judith L

2018-05-30

Electric field control of magnetism is a critical future technology for low-power, ultrahigh density memory. However, despite intensive research efforts, no practical material systems have emerged. Interface-coupled, composite systems containing ferroelectric and ferri-/ferromagnetic elements have been widely explored, but they have a range of problems, for example, substrate clamping, large leakage, and inability to miniaturize. In this work, through careful material selection, design, and nanoengineering, a high-performance room-temperature magnetoelectric system is demonstrated. The clamping problem is overcome by using a vertically aligned nanocomposite structure in which the strain coupling is independent of the substrate. To overcome the leakage problem, three key novel advances are introduced: a low leakage ferroelectric, Na 0.5 Bi 0.5 TiO 3 ; ferroelectric-ferrimagnetic vertical interfaces which are not conducting; and current blockage via a rectifying interface between the film and the Nb-doped SrTiO 3 substrate. The new multiferroic nanocomposite (Na 0.5 Bi 0.5 TiO 3 -CoFe 2 O 4 ) thin-film system enables, for the first time, large-scale in situ electric field control of magnetic anisotropy at room temperature in a system applicable for magnetoelectric random access memory, with a magnetoelectric coefficient of 1.25 × 10 -9 s m -1 .

Outcomes of robot-assisted simple enucleation of renal masses: A single European center experience.

PubMed

Matei, Deliu Victor; Vartolomei, Mihai Dorin; Musi, Gennaro; Renne, Giuseppe; Tringali, Valeria Maria Lucia; Mistretta, Francesco Alessandro; Delor, Maurizio; Russo, Andrea; Cioffi, Antonio; Bianchi, Roberto; Cozzi, Gabriele; Di Trapani, Ettore; Bottero, Danilo; Cordima, Giovanni; Lucarelli, Giuseppe; Ferro, Matteo; de Cobelli, Ottavio

2017-05-01

The aim of this study was to assess the ability of pre-and intraoperative parameters, to predict the risk of perioperative complications after robot-assisted laparoscopic simple enucleation (RASE) of renal masses, and to evaluate the rate of trifecta achievement of this approach stratifying the cohort according to the use of ischemia during the enucleation.From April 2009 to June 2016, 129 patients underwent RASE at our Institution. We stratified the procedures in 2 groups: clamping and clamp-less RASE. After RASE, all specimens were retrospectively reviewed to assess the surface-intermediate-base (SIB) scoring system. Patients were followed-up according to the European Association of Urology guidelines recommendations. All pre-, intra-, and postoperative outcomes were prospectively collected in a customized database and retrospectively analyzed.A total of 112 (86.8%) patients underwent a pure RASE and 17 (13.2%) had a hybrid according to SIB classification system. The mean age was 61.17 years. In 21 patients (16.3%), complications occurred, 13 (61.9%) were Clavien 1 and 2, while 8 were Clavien 3a and b complications. Statistical significant association with complications was found in patients with American Society of Anestesiology (ASA) score 3 (44.5%, P = .04), longer mean operative time (OT) 195 versus 161.36 minutes (P =.03), mean postoperative hemoglobin (Hb) 10.1 versus 11.8 (P <.001), and mean ΔHb 3.59 versus 2.18 (P <.001). In multivariate logistic regression, only longer OT and ΔHb were statistical significant predictive factors for complications. In sub-group analysis, clamp-less RASE was safe in terms of complications (14.1%), positive surgical margins (1.3%), and mid-term local recurrence (1.3%). Although in this approach there is higher EBL (P = .01), this had no impact on ΔHb (P = .28). A clamp-less approach was associated with a higher rate of SIB 0 (71.8% vs 51%, P = .02), higher trifecta achievement (84.6% vs 62.7%, P = .004), and better impact on serum creatinine (mean 0.83 vs 0.91, P = .01).RASE of renal tumors is a safe technique with very good postoperative outcomes. Complication rate is low and associated with ASA score >3, longer OT, and ΔHb. RASE is suitable for the clamp-less approach, which allows to perform easier the pure enucleation (SIB 0) and to obtain higher rates of trifecta outcomes.

Fiber optic to integrated optical chip coupler

NASA Technical Reports Server (NTRS)

Pikulski, Joseph I. (Inventor); Ramer, O. Glenn (Inventor)

1987-01-01

Optical fibers are clamped by a block onto a substrate. Thereupon, metal is plated over the fibers to hold them in place upon the substrate. The clamp block is removed and the opening, resulting from the clamp block's presence, is then plated in. The built-up metallic body is a coupling which holds the fibers in position so that the ends can be polished for coupling to an integrated optical chip upon a coupling fixture.

The Anion Paradox in Sodium Taste Reception: Resolution by Voltage-Clamp Studies

NASA Astrophysics Data System (ADS)

Ye, Qing; Heck, Gerard L.; Desimone, John A.

1991-11-01

Sodium salts are potent taste stimuli, but their effectiveness is markedly dependent on the anion, with chloride yielding the greatest response. The cellular mechanisms that mediate this phenomenon are not known. This "anion paradox" has been resolved by considering the field potential that is generated by restricted electrodiffusion of the anion through paracellular shunts between taste-bud cells. Neural responses to sodium chloride, sodium acetate, and sodium gluconate were studied while the field potential was voltage-clamped. Clamping at electronegative values eliminated the anion effect, whereas clamping at electropositive potentials exaggerated it. Thus, field potentials across the lingual epithelium modulate taste reception, indicating that the functional unit of taste reception includes the taste cell and its paracellular microenvironment.

Improvements of vacuum system in J-PARC 3 GeV synchrotron

NASA Astrophysics Data System (ADS)

Kamiya, J.; Hikichi, Y.; Namekawa, Y.; Takeishi, K.; Yanagibashi, T.; Kinsho, M.; Yamamoto, K.; Sato, A.

2017-07-01

The RCS vacuum system has been upgraded since the completion of its construction towards the objectives of both better vacuum quality and higher reliability of the components. For the better vacuum quality, (1) pressure of the injection beam line was improved to prevent the H-beam from converting to H0; (2) leakage in the beam injection area due to the thermal expansion was eliminated by applying the adequate torque amount for the clamps; (3) new in-situ degassing method of the kicker magnet was developed. For the reliability increase of the components, (1) A considerable number of fluoroelastmer seal was exchanged to metal seal with the low spring constant bellows and the light clamps; (2) TMP controller for the long cable was developed to prevent the controller failure by the severe electrical noise; (3) A number of TMP were installed instead of ion pumps in the RF cavity section as an insurance for the case of pump trouble.

The Electrophysiological MEMS Device with Micro Channel Array for Cellular Network Analysis

NASA Astrophysics Data System (ADS)

Tonomura, Wataru; Kurashima, Toshiaki; Takayama, Yuzo; Moriguchi, Hiroyuki; Jimbo, Yasuhiko; Konishi, Satoshi

This paper describes a new type of MCA (Micro Channel Array) for simultaneous multipoint measurement of cellular network. Presented MCA employing the measurement principles of the patch-clamp technique is designed for advanced neural network analysis which has been studied by co-authors using 64ch MEA (Micro Electrode Arrays) system. First of all, sucking and clamping of cells through channels of developed MCA is expected to improve electrophysiological signal detections. Electrophysiological sensing electrodes integrated around individual channels of MCA by using MEMS (Micro Electro Mechanical System) technologies are electrically isolated for simultaneous multipoint measurement. In this study, we tested the developed MCA using the non-cultured rat's cerebral cortical slice and the hippocampal neurons. We could measure the spontaneous action potential of the slice simultaneously at multiple points and culture the neurons on developed MCA. Herein, we describe the experimental results together with the design and fabrication of the electrophysiological MEMS device with MCA for cellular network analysis.

Analysis of the Nova Stat Strip® glucose meter for real-time blood glucose determinations during glucose clamp studies: "don't swap horses in midstream".

PubMed

Heinemann, Lutz

2010-09-01

Proper performance of glucose clamps is critically dependent on reliable blood glucose (BG) measurements. A number of requirements have to be fulfilled by a system that aims to replace the laboratory devices that are currently in use. Many more aspects need to be taken into account besides the accuracy of BG measurement. It might very well be that the BG meter studied by Rabiee and colleagues in this issue of Journal of Diabetes Science and Technology fulfills most or all of such requirements; however, these aspects have to be tested more thoroughly before one switches from an established measurement method to the Nova Stat Strip® glucometer. © 2010 Diabetes Technology Society.

A universal procedure for evaluation and application of surge-protective devices

NASA Technical Reports Server (NTRS)

1980-01-01

The source, nature, and frequency of occurrence of transients must be identified and a representative standard test wave chosen for proof testing. The performance of candidate suppressor devices then can be evaluated against the withstand goals set for the equipment. The various suppressors divide into two classes of generic behavior. The key to a universal procedure for evaluating both classes lies in representing transients as quasi-current sources of defined current impulse duration. The available surge current is established by the Thevenin equivalent transient voltage and source impedance. A load line drawn on the V-I characteristic graph of the suppressor quickly determines the clamping voltage and peak current. These values then can be compared to the requirement. The deposited energy and average power dissipation for multiple transients also can be calculated. The method is illustrated with a design example for motor vehicle alternator load dump suppression.

Kinetics and components of the flash photocurrent of isolated retinal rods of the larval salamander, Ambystoma tigrinum.

PubMed Central

Cobbs, W H; Pugh, E N

1987-01-01

1. Membrane currents initiated by intense, 20 microseconds flashes (photocurrents) were recorded from isolated salamander rods by combined extracellular suction electrodes and intracellular tight-seal electrodes either in current or voltage clamp mode. The magnitudes (mean +/- 2 S.E.M.) of the maximal photoresponses recorded by the suction and by the intracellular electrode respectively were 40 +/- 5 pA (n = 18) and 35 +/- 7 mV (n = 8) for current clamp at zero current; 43 +/- 9 pA and 66 +/- 13 (n = 11) pA for voltage clamp at the zero-current holding potential, -24 +/- 3 mV. 2. Photocurrents initiated by flashes isomerizing 0.1% or more of the outer segment's rhodopsin achieved a saturated velocity and were 95% complete in less than 50 ms. The effect of incrementing flash intensity above 0.1% isomerization can be described as a translation of the photocurrent along the time axis towards the origin. Within the interval 0-50 ms the latter two-thirds of the velocity-saturated photocurrent is well described as a single-exponential decay. The decay was much faster in voltage clamp (2.8 +/- 1.2 ms, n = 11) than in current clamp mode (17 +/- 5 ms, n = 17). 3. The initial third of the velocity-saturated photocurrent, occurring over the interval from the flash to the onset of exponential decay, followed about the same time course in current and voltage clamp. The time interval occupied by this initial 'latent' phase decreased with increasing flash intensity and attained an apparent minimum of about 7 ms in response to flashes isomerizing 10% or more of the rhodopsin at ca. 22 degrees C. 4. The hypothesis that the decay of outer segment light-sensitive membrane current is the same in current and voltage clamp was supported by an analysis of the difference between outer segment currents measured successively in the two recording modes. First, the tail of the difference current decayed exponentially with a time constant approximately equal to R x C, where R and C are independently estimated slope resistance and capacitance of the rod. Secondly, the integral of the difference current, when divided by outer segment capacitance, closely approximated the hyperpolarizing light response measured under current clamp. Thus, displacement current accounted for the difference between photocurrents measured in current and voltage clamp.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:2832596

Combined acute hyperglycemic and hyperinsulinemic clamp induced profibrotic and proinflammatory responses in the kidney

PubMed Central

DeSilva, Kristin; Sorice, Gian Pio; Muscogiuri, Giovanna; Jimenez, Fabio; Ahuja, Seema; Barnes, Jefferey L.; Choudhury, Goutam Ghosh; Musi, Nicolas; DeFronzo, Ralph; Kasinath, Balakuntalam S.

2013-01-01

Increase in matrix protein content in the kidney is a cardinal feature of diabetic kidney disease. While renal matrix protein content is increased by chronic hyperglycemia, whether it is regulated by acute elevation of glucose and insulin has not been addressed. In this study, we aimed to evaluate whether short duration of combined hyperglycemia and hyperinsulinemia, mimicking the metabolic environment of prediabetes and early type 2 diabetes, induces kidney injury. Normal rats were subjected to either saline infusion (control, n = 4) or 7 h of combined hyperglycemic-hyperinsulinemic clamp (HG+HI clamp; n = 6). During the clamp, plasma glucose and plasma insulin were maintained at about 350 mg/dl and 16 ng/ml, respectively. HG+HI clamp increased the expression of renal cortical transforming growth factor-β (TGF-β) and renal matrix proteins, laminin and fibronectin. This was associated with the activation of SMAD3, Akt, mammalian target of rapamycin (mTOR) complexes, and ERK signaling pathways and their downstream target events in the initiation and elongation phases of mRNA translation, an important step in protein synthesis. Additionally, HG+HI clamp provoked renal inflammation as shown by the activation of Toll-like receptor 4 (TLR4) and infiltration of CD68-positive monocytes. Urinary F2t isoprostane excretion, an index of renal oxidant stress, was increased in the HG+HI clamp rats. We conclude that even a short duration of hyperglycemia and hyperinsulinemia contributes to activation of pathways that regulate matrix protein synthesis, inflammation, and oxidative stress in the kidney. This finding could have implications for the control of short-term rises in blood glucose in diabetic individuals at risk of developing kidney disease. PMID:24108867

Combined acute hyperglycemic and hyperinsulinemic clamp induced profibrotic and proinflammatory responses in the kidney.

PubMed

Mariappan, Meenalakshmi M; DeSilva, Kristin; Sorice, Gian Pio; Muscogiuri, Giovanna; Jimenez, Fabio; Ahuja, Seema; Barnes, Jefferey L; Choudhury, Goutam Ghosh; Musi, Nicolas; DeFronzo, Ralph; Kasinath, Balakuntalam S

2014-02-01

Increase in matrix protein content in the kidney is a cardinal feature of diabetic kidney disease. While renal matrix protein content is increased by chronic hyperglycemia, whether it is regulated by acute elevation of glucose and insulin has not been addressed. In this study, we aimed to evaluate whether short duration of combined hyperglycemia and hyperinsulinemia, mimicking the metabolic environment of prediabetes and early type 2 diabetes, induces kidney injury. Normal rats were subjected to either saline infusion (control, n = 4) or 7 h of combined hyperglycemic-hyperinsulinemic clamp (HG+HI clamp; n = 6). During the clamp, plasma glucose and plasma insulin were maintained at about 350 mg/dl and 16 ng/ml, respectively. HG+HI clamp increased the expression of renal cortical transforming growth factor-β (TGF-β) and renal matrix proteins, laminin and fibronectin. This was associated with the activation of SMAD3, Akt, mammalian target of rapamycin (mTOR) complexes, and ERK signaling pathways and their downstream target events in the initiation and elongation phases of mRNA translation, an important step in protein synthesis. Additionally, HG+HI clamp provoked renal inflammation as shown by the activation of Toll-like receptor 4 (TLR4) and infiltration of CD68-positive monocytes. Urinary F2t isoprostane excretion, an index of renal oxidant stress, was increased in the HG+HI clamp rats. We conclude that even a short duration of hyperglycemia and hyperinsulinemia contributes to activation of pathways that regulate matrix protein synthesis, inflammation, and oxidative stress in the kidney. This finding could have implications for the control of short-term rises in blood glucose in diabetic individuals at risk of developing kidney disease.

Long-Time Choledochal Clamping in Wistar Rats Causes Biliary Obstruction Progressing to Hepatic Fibrosis.

PubMed

Jorge, G D L; Tártaro, R R; Escanhoela, C A F; Boin, I D F S F

2016-09-01

Biliary complications are important causes of morbidity and mortality in patients undergoing hepatic surgery. The aim of the study was to evaluate late liver alterations after a long period of choledochal clamping in Wistar rats. Ten male Wistar rats, weighing 304 grams, anesthetized with sodium thiopental (25 mg/kg) and xylazine (10 mg/kg) intravenously, were distributed into 2 groups: the choledochal clamping group (CCG) and the operation sham group (OSG), with 5 animals each submitted to an abdominal incision. In the CCG, the choledochal was isolated, dissected, and clamped with a microvascular clamp for 40 minutes. After this occlusion time, the clamp was removed and the incision was closed. In the OSG the animals, under normal conditions, were submitted only to anesthesia and laparotomy for choledochal manipulation. In all animals, after the 31st day, a hepatic biopsy was carried out for histology and blood biochemical tests: total bilirubin, alkaline phosphatase, aspartate aminotransferase, alanine aminotransferase, and gamma-glutamyl transferase. The animals were euthanized under anesthesia. This research was approved by the Ethics Committee on Animal Use (CEUA, Unicamp, No. 2511-1). In the CCG, 100% of the animals showed bile duct dilatation, ductular proliferation, and portal inflammatory infiltrate; 60% showed regenerative nodule formation; and 80% had porta-porta septa and foci of necrosis, all of which were not found in the OSG. All CCG group biochemical tests had significant increases (P < .05) compared with OSG. Long-time choledochal clamping in Wistar rats caused hepatic dysfunction and biochemical and histological injuries with degrees of distortion to the hepatic architecture. Copyright © 2016 Elsevier Inc. All rights reserved.

Can robots patch-clamp as well as humans? Characterization of a novel sodium channel mutation

PubMed Central

Estacion, M; Choi, J S; Eastman, E M; Lin, Z; Li, Y; Tyrrell, L; Yang, Y; Dib-Hajj, S D; Waxman, S G

2010-01-01

Ion channel missense mutations cause disorders of excitability by changing channel biophysical properties. As an increasing number of new naturally occurring mutations have been identified, and the number of other mutations produced by molecular approaches such as in situ mutagenesis has increased, the need for functional analysis by patch-clamp has become rate limiting. Here we compare a patch-clamp robot using planar-chip technology with human patch-clamp in a functional assessment of a previously undescribed Nav1.7 sodium channel mutation, S211P, which causes erythromelalgia. This robotic patch-clamp device can increase throughput (the number of cells analysed per day) by 3- to 10-fold. Both modes of analysis show that the mutation hyperpolarizes activation voltage dependence (−8 mV by manual profiling, −11 mV by robotic profiling), alters steady-state fast inactivation so that it requires an additional Boltzmann function for a second fraction of total current (∼20% manual, ∼40% robotic), and enhances slow inactivation (hyperpolarizing shift −15 mV by human, −13 mV robotic). Manual patch-clamping demonstrated slower deactivation and enhanced (∼2-fold) ramp response for the mutant channel while robotic recording did not, possibly due to increased temperature and reduced signal-to-noise ratio on the robotic platform. If robotic profiling is used to screen ion channel mutations, we recommend that each measurement or protocol be validated by initial comparison to manual recording. With this caveat, we suggest that, if results are interpreted cautiously, robotic patch-clamp can be used with supervision and subsequent confirmation from human physiologists to facilitate the initial profiling of a variety of electrophysiological parameters of ion channel mutations. PMID:20123784

Fasting insulin sensitivity indices are not better than routine clinical variables at predicting insulin sensitivity among Black Africans: a clamp study in sub-Saharan Africans

PubMed Central

2014-01-01

Background We aimed to evaluate the predictive utility of common fasting insulin sensitivity indices, and non-laboratory surrogates [BMI, waist circumference (WC) and waist-to-height ratio (WHtR)] in sub-Saharan Africans without diabetes. Methods We measured fasting glucose and insulin, and glucose uptake during 80/mU/m2/min euglycemic clamp in 87 Cameroonians (51 men) aged (SD) 34.6 (11.4) years. We derived insulin sensitivity indices including HOMA-IR, quantitative insulin sensitivity check index (QUICKI), fasting insulin resistance index (FIRI) and glucose-to-insulin ratio (GIR). Indices and clinical predictors were compared to clamp using correlation tests, robust linear regressions and agreement of classification by sex-specific thirds. Results The mean insulin sensitivity was M = 10.5 ± 3.2 mg/kg/min. Classification across thirds of insulin sensitivity by clamp matched with non-laboratory surrogates in 30-48% of participants, and with fasting indices in 27-51%, with kappa statistics ranging from −0.10 to 0.26. Fasting indices correlated significantly with clamp (/r/=0.23-0.30), with GIR performing less well than fasting insulin and HOMA-IR (both p < 0.02). BMI, WC and WHtR were equal or superior to fasting indices (/r/=0.38-0.43). Combinations of fasting indices and clinical predictors explained 25-27% of variation in clamp values. Conclusion Fasting insulin sensitivity indices are modest predictors of insulin sensitivity measured by euglycemic clamp, and do not perform better than clinical surrogates in this population. PMID:25106496

Randomized clinical trial of stapler versus clamp-crushing transection in elective liver resection.

PubMed

Rahbari, N N; Elbers, H; Koch, M; Vogler, P; Striebel, F; Bruckner, T; Mehrabi, A; Schemmer, P; Büchler, M W; Weitz, J

2014-02-01

Various devices have been developed to facilitate liver transection and reduce blood loss in liver resections. None of these has proven superiority compared with the classical clamp-crushing technique. This randomized clinical trial compared the effectiveness and safety of stapler transection with that of clamp-crushing during open liver resection. Patients admitted for elective open liver resection between January 2010 and October 2011 were assigned randomly to stapler transection or the clamp-crushing technique. The primary endpoint was the total amount of intraoperative blood loss. Secondary endpoints included transection time, duration of operation, complication rates and resection margins. A total of 130 patients were enrolled, 65 to clamp-crushing and 65 to stapler transection. There was no difference between groups in total intraoperative blood loss: median (i.q.r.) 1050 (525-1650) versus 925 (450-1425) ml respectively (P = 0·279). The difference in total intraoperative blood loss normalized to the transection surface area was not statistically significant (P = 0·092). Blood loss during parenchymal transection was significantly lower in the stapler transection group (P = 0·002), as were the parenchymal transection time (mean(s.d.) 30(21) versus 9(7) min for clamp-crushing and stapler transection groups respectively; P < 0·001) and total duration of operation (mean(s.d.) 221(86) versus 190(85) min; P = 0·047). There were no significant differences in postoperative morbidity (P = 0·863) or mortality (P = 0·684) between groups. Stapler transection is a safe technique but does not reduce intraoperative blood loss in elective liver resection compared with the clamp-crushing technique. NCT01049607 (http://www.clinicaltrials.gov). © 2014 BJS Society Ltd. Published by John Wiley & Sons Ltd.

Screening of E. coli β-clamp Inhibitors Revealed that Few Inhibit Helicobacter pylori More Effectively: Structural and Functional Characterization.

PubMed

Pandey, Preeti; Verma, Vijay; Dhar, Suman Kumar; Gourinath, Samudrala

2018-01-11

The characteristic of interaction with various enzymes and processivity-promoting nature during DNA replication makes β-clamp an important drug target. Helicobacter pylori ( H. pylori ) have several unique features in DNA replication machinery that makes it different from other microorganisms. To find out whether difference in DNA replication proteins behavior accounts for any difference in drug response when compared to E. coli , in the present study, we have tested E. coli β-clamp inhibitor molecules against H. pylori β-clamp. Various approaches were used to test the binding of inhibitors to H. pylori β-clamp including docking, surface competition assay, complex structure determination, as well as antimicrobial assay. Out of five shortlisted inhibitor molecules on the basis of docking score, three molecules, 5-chloroisatin, carprofen, and 3,4-difluorobenzamide were co-crystallized with H. pylori β-clamp and the structures show that they bind at the protein-protein interaction site as expected. In vivo studies showed only two molecules, 5-chloroisatin, and 3,4-difluorobenzamide inhibited the growth of the pylori with MIC values in micro molar range, which is better than the inhibitory effect of the same drugs on E. coli . Therefore, the evaluation of such drugs against H. pylori may explore the possibility to use to generate species-specific pharmacophore for development of new drugs against H. pylori .

An Ultrasonic Clamp for Bloodless Partial Nephrectomy

NASA Astrophysics Data System (ADS)

Lafon, Cyril; Bouchoux, Guillaume; Murat, François Joseph; Birer, Alain; Theillère, Yves; Chapelon, Jean Yves; Cathignol, Dominique

2007-05-01

Maximum conservation of the kidney is preferable through partial nephrectomy for patients at risk of disease recurrence of renal cancers. Haemostatic tools are needed in order to achieve bloodless surgery and reduce post surgery morbidity. Two piezo-ceramic transducers operating at a frequency of 4 MHz were mounted on each arm of a clamp. When used for coagulation purposes, two transducers situated on opposite arms of the clamp were driven simultaneously. Heat delivery was optimized as each transducers mirrored back to targeted tissues the wave generated by the opposite transducer. Real-time treatment monitoring with an echo-based technique was also envisaged with this clamp. Therapy was periodically interrupted so one transducer could generate a pulse. The echo returning from the opposite transducer was treated. Coagulation necroses were obtained in vitro on substantial thicknesses (23-38mm) of pig liver over exposure durations ranging from 30s to 130s, and with acoustic intensities of less than 15W/cm2 per transducer. Both kidneys of two pigs were treated in vivo with the clamp (14.5W/cm2 for 90s), and the partial nephrectomies performed proved to be bloodless. In vitro and in vivo, wide transfixing lesions corresponded to an echo energy decrease superior to -10dB and parabolic form of the time of flight versus treatment time. In conclusion, this ultrasound clamp has proven to be an excellent mean for achieving monitored haemostasis in kidney.

Cold cardioplegia versus hypothermia for myocardial protection. Randomized clinical study.

PubMed

Conti, V R; Bertranou, E G; Blackstone, E H; Kirklin, J W; Digerness, S B

1978-11-01

Seventeen of 34 consecutive patients undergoing coronary artery bypass grafting were randomly assigned to one of two methods of myocardial preservation. With the cold cardioplegic method (Group A), a 4 degrees C. asanguineous solution with 30 mEq. of potassium per liter was infused into the aortic root for about 2 minutes immediately after aortic cross-clamping and again after about 45 minutes or when myocardial temperature rose above 19 degrees C. External cardiac cooling was provided by constant infusion of 4 degrees C. Ringer's solution into the pericardium. Seventeen patients were assigned to simple cardiac cooling by hypothermic systemic perfusion before aortic cross-clamping plus external cardiac cooling (Group B). Electromechanical activity ceased within 1 to 2 minutes in Group A but continued throughout the ischemic period in 14 patients in Group B. Myocardial temperature (mean for all observations) during aortic cross-clamping was 17.2 +/- 0.44 degrees C. In Group A and 24.0 +/- 0.70 degrees C. in Group B. Operating conditions were better in Group A. Card-ac function early postoperatively was good in both groups clinically and according to measurements, but only in the cold cardioplegic group (A) was cardiac index not adversely affected by longer cross-clamp time. Myocardial necrosis occurred in both groups but was probably less in the cold cardioplegic group. Thirteen patients (76 percent) in Group A had no electrocardiographic evidence of myocardial injury, compared with eight (47 percent) in Group B (p = 0.08). Eleven (65 percent of Group A had no or short-lived appearance of ceatine phosphokinase isoenzyme (CK-MB), compared with six (35 percent) of Group B (p = 0.08). Time-related CK-MB and SGOT mean levels were consistently lower in Group A.

The assessment of electrophysiological activity in human-induced pluripotent stem cell-derived cardiomyocytes exposed to dimethyl sulfoxide and ethanol by manual patch clamp and multi-electrode array system.

PubMed

Hyun, Soo-Wang; Kim, Bo-Ram; Hyun, Sung-Ae; Seo, Joung-Wook

2017-09-01

Recently, electrophysiological activity has been effectively measured in human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) to predict drug-induced arrhythmia. Dimethyl sulfoxide (DMSO) and ethanol have been used as diluting agents in many experiments. However, the maximum DMSO and ethanol concentrations that can be effectively used in the measurement of electrophysiological parameters in hiPSC-CMs-based patch clamp and multi-electrode array (MEA) have not been fully elucidated. We investigated the effects of varying concentrations of DMSO and ethanol used as diluting agents on several electrophysiological parameters in hiPSC-CMs using patch clamp and MEA. Both DMSO and ethanol at concentrations>1% in external solution resulted in osmolality >400mOsmol/kg, but pH was not affected by either agent. Neither DMSO nor ethanol led to cell death at the concentrations examined. However, resting membrane potential, action potential amplitude, action potential duration at 90% and 40%, and corrected field potential duration were decreased significantly at 1% ethanol concentration. DMSO at 1% also significantly decreased the sodium spike amplitude. In addition, the waveform of action potential and field potential was recorded as irregular at 3% concentrations of both DMSO and ethanol. Concentrations of up to 0.3% of either agent did not affect osmolality, pH, cell death, or electrophysiological parameters in hiPSC-CMs. Our findings suggest that 0.3% is the maximum concentration at which DMSO or ethanol should be used for dilution purposes in hiPSC-CMs-based patch clamp and MEA. Copyright © 2017 Elsevier Inc. All rights reserved.

Sliding Clamp of DNA Polymerase III as a Drug Target for TB Therapy: Comprehensive Conformational and Binding Analysis from Molecular Dynamic Simulations.

PubMed

Machaba, Kgothatso E; Cele, Favorite N; Mhlongo, Ndumiso N; Soliman, Mahmoud E S

2016-12-01

Tuberculosis, caused by Mycobacterium tuberculosis, is one of the most common causes of death in the world. Mycobacterium tuberculosis -sliding clamp is a protein essential for many important DNA transactions including replication and DNA repair proteins, thus, a potential drug target for tuberculosis. Further investigation is needed in understanding DNA polymerase sliding clamp structure, especially from a computational perspective. In this study, we employ a wide-range of comparative molecular dynamic analyses on two systems: Mycobacterium tuberculosis - sliding clamp enzyme in its apo and bound form. The results reported in this study shows apo conformation to be less stable, as compared to bound conformation with an average radius of gyration of 25.812 and 25.459 Å, respectively. This was further supported by root mean square fluctuation, where an apo enzyme showed a higher degree of flexibility. However, the presence of the ligand lowers radius of gyration and root mean square fluctuation and also leads to an existence of negative correlated motions. Principal component analysis further justifies the same findings, whereby the apo enzyme exhibits a higher fluctuation compared to the bound complex. In addition, a stable 3 10 helix located at the binding site appears to be unstable in the presence of the ligand. Hence, it is possible that the binding of the ligand may have caused a rearrangement of the structure, leading to a change in the unwinding of 3 10 helix. Findings reported in this study further enhance the understanding of Mycobacterium tuberculosis -DnaN and also give a lead to the development of potent tuberculosis drugs.

Analysis of motion during the breast clamping phase of mammography

PubMed Central

McEntee, Mark F; Mercer, Claire; Kelly, Judith; Millington, Sara; Hogg, Peter

2016-01-01

Objective: To measure paddle motion during the clamping phase of a breast phantom for a range of machine/paddle combinations. Methods: A deformable breast phantom was used to simulate a female breast. 12 mammography machines from three manufacturers with 22 flexible and 20 fixed paddles were evaluated. Vertical motion at the paddle was measured using two calibrated linear potentiometers. For each paddle, the motion in millimetres was recorded every 0.5 s for 40 s, while the phantom was compressed with 80 N. Independent t-tests were used to determine differences in paddle motion between flexible and fixed, small and large, GE Senographe Essential (General Electric Medical Systems, Milwaukee, WI) and Hologic Selenia Dimensions paddles (Hologic, Bedford, MA). Paddle tilt in the medial–lateral plane for each machine/paddle combination was calculated. Results: All machine/paddle combinations demonstrate highest levels of motion during the first 10 s of the clamping phase. The least motion is 0.17 ± 0.05 mm/10 s (n = 20) and the most motion is 0.51 ± 0.15 mm/10 s (n = 80). There is a statistical difference in paddle motion between fixed and flexible (p < 0.001), GE Senographe Essential and Hologic Selenia Dimensions paddles (p < 0.001). Paddle tilt in the medial–lateral plane is independent of time and varied from 0.04 ° to 0.69 °. Conclusion: All machine/paddle combinations exhibited motion and tilting, and the extent varied with machine and paddle sizes and types. Advances in knowledge: This research suggests that image blurring will likely be clinically insignificant 4 s or more after the clamping phase commences. PMID:26739577

Validation of a patch clamp screening protocol that simultaneously measures compound activity in multiple states of the voltage-gated sodium channel Nav1.2.

PubMed

Liu, Yi; Beck, Edward J; Flores, Christopher M

2011-12-01

Hyperactivity of voltage-gated sodium channels underlies, at least in part, a range of pathological states, including pain and epilepsy. Selective blockers of these channels may offer effective treatment of such disorders. Currently employed methods to screen for sodium channel blockers, however, are inadequate to rationally identify mechanistically diverse blockers, limiting the potential range of indications that may be treated by such agents. Here, we describe an improved patch clamp screening assay that increases the mechanistic diversity of sodium channel blockers being identified. Using QPatch HT, a medium-throughput, automated patch clamp system, we tested three common sodium channel blockers (phenytoin, lidocaine, and tetrodotoxin) with distinct mechanistic profiles at Nav1.2. The single-voltage protocol employed in this assay simultaneously measured the compound activity in multiple states, including the slow inactivated state, of the channel. A long compound incubation period (10 s) was introduced during channel inactivation to increase the probability of identifying "slow binders." As such, phenytoin, which preferentially binds with slow kinetics to the fast inactivated state, exhibited significantly higher potency than that obtained from a brief exposure (100 ms) used in typical assays. This assay also successfully detected the use-dependent block of tetrodotoxin, a well-documented property of this molecule yet unobserved in typical patch clamp protocols. These results indicate that the assay described here can increase the likelihood of identification and mechanistic diversity of sodium channel blockers from a primary screen. It can also be used to efficiently guide the in vitro optimization of leads that retain the desired mechanistic properties. © MARY ANN LIEBERT, INC.

Accuracy and trending ability of the fourth-generation FloTrac/Vigileo System™ in patients undergoing abdominal aortic aneurysm surgery.

PubMed

Maeda, Takuma; Hattori, Kohshi; Sumiyoshi, Miho; Kanazawa, Hiroko; Ohnishi, Yoshihiko

2018-06-01

The fourth-generation FloTrac/Vigileo™ improved its algorithm to follow changes in systemic vascular resistance index (SVRI). This revision may improve the accuracy and trending ability of CI even in patients who undergo abdominal aortic aneurysm (AAA) surgery which cause drastic change of SVRI by aortic clamping. The purpose of this study is to elucidate the accuracy and trending ability of the fourth-generation FloTrac/Vigileo™ in patients with AAA surgery by comparing the FloTrac/Vigileo™-derived CI (CI FT ) with that measured by three-dimensional echocardiography (CI 3D ). Twenty-six patients undergoing elective AAA surgery were included in this study. CI FT and CI3 D were determined simultaneously in eight points including before and after aortic clamp. We used CI 3D as the reference method. In the Bland-Altman analysis, CI FT had a wide limit of agreement with CI 3D showing a percentage error of 46.7%. Subgroup analysis showed that the percentage error between CO 3D and CO FT was 56.3% in patients with cardiac index < 2.5 L/min/m 2 and 28.4% in patients with cardiac index ≥ 2.5 L/min/m 2 . SVRI was significantly higher in patients with cardiac index < 2.5 L/min/m 2 (1703 ± 330 vs. 2757 ± 798; p < 0.001). The tracking ability of fourth generation of FloTrac/Vigileo™ after aortic clamp was not clinically acceptable (26.9%). The degree of accuracy of the fourth-generation FloTrac/Vigileo™ in patients with AAA surgery was not acceptable. The tracking ability of the fourth-generation FloTrac/Vigileo™ after aortic clamp was below the acceptable limit.

The Clementine mechanisms

NASA Technical Reports Server (NTRS)

Purdy, William; Hurley, Michael

1995-01-01

The Clementine spacecraft was developed under the 'faster, better, cheaper' theme. The constraints of a low budget coupled with an unusually tight schedule forced many departures from the normal spacecraft development methods. This paper discusses technical lessons learned about several of the mechanisms on the Clementine spacecraft as well as managerial lessons learned for the entire mechanisms subsystem. A quick overview of the Clementine mission is included; the mission schedule and environment during the mechanisms releases and deployment are highlighted. This paper then describes the entire mechanisms subsystem. The design and test approach and key philosophies for a fast-track program are discussed during the description of the mechanisms subsystem. The mechanism subsystem included a marman clamp separation system, a separation nut separation system, a solar panel deployment and pointing system, a high gain antenna feed deployment system, and two separate sensor cover systems. Each mechanism is briefly discussed. Additional technical discussion is given on the marman clamp design, the sensor cover designs, and the design and testing practices for systems driven by heated actuators (specifically paraffin actuators and frangibolts). All of the other mechanisms were of conventional designs and will receive less emphasis. Lessons learned are discussed throughout the paper as they applied to the systems being discussed. Since there is information on many different systems, this paper is organized so that information on a particular topic can be quickly referenced.

Inertial piezoelectric linear motor driven by a single-phase harmonic wave with automatic clamping mechanism

NASA Astrophysics Data System (ADS)

He, Liangguo; Chu, Yuheng; Hao, Sai; Zhao, Xiaoyong; Dong, Yuge; Wang, Yong

2018-05-01

A novel, single-phase, harmonic-driven, inertial piezoelectric linear motor using an automatic clamping mechanism was designed, fabricated, and tested to reduce the sliding friction and simplify the drive mechanism and power supply control of the inertial motor. A piezoelectric bimorph and a flexible hinge were connected in series to form the automatic clamping mechanism. The automatic clamping mechanism was used as the driving and clamping elements. A dynamic simulation by Simulink was performed to prove the feasibility of the motor. The finite element method software COMSOL was used to design the structure of the motor. An experimental setup was built to validate the working principle and evaluate the performance of the motor. The prototype motor outputted a no-load velocity of 3.178 mm/s at a voltage of 220 Vp-p and a maximum traction force of 4.25 N under a preload force of 8 N. The minimum resolution of 1.14 μm was achieved at a driving frequency of 74 Hz, a driving voltage of 50 Vp-p, and a preload force of 0 N.

Actuation of Piezoelectric Layered Beams With and Coupling.

PubMed

Nguyen, Cuong H; Hanke, Ulrik; Halvorsen, Einar

2018-05-01

In this paper, we derive and compare the linear static bending of piezoelectric actuators with transversal ( ) and longitudinal ( ) coupling. The transducers are, respectively, structures utilizing top and bottom electrodes (TBEs) and interdigitated electrodes (IDEs). While the theory is well developed for the TBE beam, governing equations for the bending of the piezoelectric beams with IDEs are far less developed. We improve on this by deriving the governing equation for the IDE beam with an arbitrary number of layers and with coupling consistently included. In addition, we introduce a phenomenological quadratic form for the nonuniform field that lets us derive a deflection formula with nontrivial effects of the field accounted for. The theory is applied to derive deflection formulas for both cantilever and clamped-clamped beams. All analytic results are validated with numerical simulations. From the analytic models, two different figures of merit (FOMs) are derived. We show that these FOMs are the same for cantilevers and doubly clamped beams. The analysis indicates the optimal transducer length for clamped-clamped beams and gives a criterion that can be used to determine which design concept ( or ) gives the largest deflection.

Verification of the windings axial clamping forces for high voltage power transformers by using passively mode-locked fiber lasers

NASA Astrophysics Data System (ADS)

Şchiopu, IonuÅ£ Romeo; ǎgulinescu, Andrei, Dr; Iordǎnescu, Raluca; Marinescu, Andrei

2015-02-01

The current paper describes an optoelectronic method for direct monitoring of the axial clamping forces both in static and in dynamic duty. As advantages of this method we can state that it can be applied both to new and refurbished transformers without performing constructive changes or affecting in any way the transformer safety in operation. For monitoring the axial clamping forces for high-voltage (HV) power transformers, we use an optical fiber that we integrate into the laser cavity of a passively mode-locked fiber laser (PMFL). To each axial clamp corresponds a solitonic optical spectrum that is changed at the periodical passing of the fundamental soliton pulse through the sensitive fiber inside the transformer. Moreover, as a specific characteristic, the laser stability is unique for each set of axial clamping forces. Other important advantages of using an optical fiber as compared to the classical approach in which electronic sensors are used consist in the good reliability and insulator properties of the optical fiber, avoiding any risk of fire or damage of the transformer.

Robotic partial nephrectomy with selective parenchymal compression (Simon clamp).

PubMed

Castillo, O A; Rodriguez-Carlin, A; Lopez-Fontana, G; Aleman, E

2013-01-01

To present our initial experience using selective renal parenchymal ischemia, without hilar clamping, in robotic-assisted partial nephrectomy. In four patients with T1a renal tumor we performed robotic-assisted partial nephrectomy, using the Simon's clamp (Aesculap). It provides selective parenchymal compression without the need of vascular clamping. All patients had exofitic renal tumors in polar location. Renal parenchymal reconstruction was done as the standard technique. The median age was 49.6 years (42-59), 3 male and 1 female patient. Median operative time was 71,6 minutes (40-120). Mean stimated bleeding was 250 ml (50-400). Average tumor size was 3,25 cm (1,5-5,3). There were no complications and the average hospital stay was 3,5 days (1-7). The pathology was informed as renal cell carcinoma in three patients and one hemorrhagic cyst. The surgical margins were negative. Our preliminary results shows that selective renal parenchymal compression, with the Simon's clamp, provides an alternative to vascular control in selected patients with polar renal tumors. Copyright © 2012 AEU. Published by Elsevier Espana. All rights reserved.

Sinusoidal voltage protocols for rapid characterisation of ion channel kinetics.

PubMed

Beattie, Kylie A; Hill, Adam P; Bardenet, Rémi; Cui, Yi; Vandenberg, Jamie I; Gavaghan, David J; de Boer, Teun P; Mirams, Gary R

2018-03-24

Ion current kinetics are commonly represented by current-voltage relationships, time constant-voltage relationships and subsequently mathematical models fitted to these. These experiments take substantial time, which means they are rarely performed in the same cell. Rather than traditional square-wave voltage clamps, we fitted a model to the current evoked by a novel sum-of-sinusoids voltage clamp that was only 8 s long. Short protocols that can be performed multiple times within a single cell will offer many new opportunities to measure how ion current kinetics are affected by changing conditions. The new model predicts the current under traditional square-wave protocols well, with better predictions of underlying currents than literature models. The current under a novel physiologically relevant series of action potential clamps is predicted extremely well. The short sinusoidal protocols allow a model to be fully fitted to individual cells, allowing us to examine cell-cell variability in current kinetics for the first time. Understanding the roles of ion currents is crucial to predict the action of pharmaceuticals and mutations in different scenarios, and thereby to guide clinical interventions in the heart, brain and other electrophysiological systems. Our ability to predict how ion currents contribute to cellular electrophysiology is in turn critically dependent on our characterisation of ion channel kinetics - the voltage-dependent rates of transition between open, closed and inactivated channel states. We present a new method for rapidly exploring and characterising ion channel kinetics, applying it to the hERG potassium channel as an example, with the aim of generating a quantitatively predictive representation of the ion current. We fitted a mathematical model to currents evoked by a novel 8 second sinusoidal voltage clamp in CHO cells overexpressing hERG1a. The model was then used to predict over 5 minutes of recordings in the same cell in response to further protocols: a series of traditional square step voltage clamps, and also a novel voltage clamp comprising a collection of physiologically relevant action potentials. We demonstrate that we can make predictive cell-specific models that outperform the use of averaged data from a number of different cells, and thereby examine which changes in gating are responsible for cell-cell variability in current kinetics. Our technique allows rapid collection of consistent and high quality data, from single cells, and produces more predictive mathematical ion channel models than traditional approaches. © 2018 The Authors. The Journal of Physiology published by John Wiley & Sons Ltd on behalf of The Physiological Society.

Variable-speed wind power system with improved energy capture via multilevel conversion

DOEpatents

Erickson, Robert W.; Al-Naseem, Osama A.; Fingersh, Lee Jay

2005-05-31

A system and method for efficiently capturing electrical energy from a variable-speed generator are disclosed. The system includes a matrix converter using full-bridge, multilevel switch cells, in which semiconductor devices are clamped to a known constant DC voltage of a capacitor. The multilevel matrix converter is capable of generating multilevel voltage wave waveform of arbitrary magnitude and frequencies. The matrix converter can be controlled by using space vector modulation.

Inflatable Launch and Recovery System

DTIC Science & Technology

2014-07-31

clamping fixture connects the ramp structure to the vessel. A snubber element dampens vibrations and transient tow loads. Unclassified Unclassified...integrated dynamic snubber element to dampen out vibrations and transient tow loads. The main air fill line from the handling system to the inflatable ramp...of the vessel A with standard container cam locks 12a (two of which are shown in phantom in FIG. 1). The system 10 can connect to a vessel power

Microbial Fouling and its Effect on Power Generation.

DTIC Science & Technology

1981-09-01

The tubular fouling reactor system (TFR) consists of a test block heat exchanger and a support system which includes water supply treatment facilities...and measurement instrumentation. Figure 8 is a schematic diagram of the system. Test block heat exchanger : The test block heat exchanger consists of...two adjacent aluminum cylindrical blocks (12.5 cm dia.) clamped to the section of tubing being tested (Fig. 9). The block is heated by electrical re

The slow inward calcium current is responsible for a part of the contraction of patch-clamped rat myoballs.

PubMed

Rivet, M; Cognard, C; Raymond, G

1989-01-01

The slow inward calcium current and the contractile response were simultaneously recorded in voltage clamped (whole cell patch clamp recording) rat myoballs in primary culture. The shape of the contraction(T)/potential(V) relationship and the application of the inorganic calcium channel blocker cadmium (1.5 mM), which suppresses a part of the contractile activity, demonstrate the existence of two components of contraction. One of them is related to the slow calcium current.

Air Force Dynamic Mechanical Analysis Testing of NATO Round Robin Propellant Testing for Development of AOP-4717

DTIC Science & Technology

2015-08-01

10 minutes. After this, the furnace was opened and the clamps were tightened to 6 in-lb of torque . At the end of the tests, we examined the specimens...to use a different procedure for tightening the clamps in the frequency sweep tests -- this is explained in the next section...procedure to tighten the clamps. This is described next. First, the test applies different frequencies at a large range of temperatures – from -110 C to 70

Blood cardioplegia with N-acetylcysteine may reduce coronary endothelial activation and myocardial oxidative stress.

PubMed

Rodrigues, Alfredo J; Evora, Paulo R B; Bassetto, Solange; Alves, Lafaiete; Scorzoni Filho, Adilson; Origuela, Eliana A; Vicente, Walter V A

2009-01-01

The aim of this prospective study was to compare the efficacy of intermittent antegrade blood cardioplegia with or without n-acetylcysteine (NAC) in reducing myocardial oxidative stress and coronary endothelial activation. Twenty patients undergoing elective isolated coronary artery bypass graft surgery were randomly assigned to receive intermittent antegrade blood cardioplegia (32 degrees C-34 degrees C) with (NAC group) or without (control group) 300 mg of NAC. For these 2 groups we compared clinical outcome, hemodynamic evolution, systemic plasmatic levels of troponin I, and plasma concentrations of malondialdehyde (MDA) and soluble vascular adhesion molecule 1 (sVCAM-1) from coronary sinus blood samples. Patient demographic characteristics and operative and postoperative data findings in both groups were similar. There was no hospital mortality. Comparing the plasma levels of MDA 10 min after the aortic cross-clamping and of sVCAM-1 30 min after the aortic cross-clamping period with the levels obtained before the aortic clamping period, we observed increases of both markers, but the increase was significant only in the control group (P= .039 and P= .064 for MDA; P= .004 and P= .064 for sVCAM-1). In both groups there was a significant increase of the systemic serum levels of troponin I compared with the levels observed before cardiopulmonary bypass (P< .001), but the differences between the groups were not significant (P= .570). Our investigation showed that NAC as an additive to blood cardioplegia in patients undergoing on-pump coronary artery bypass graft surgery may reduce oxidative stress and the resultant coronary endothelial activation.

RELATIONSHIP BETWEEN RIGIDITY OF EXTERNAL FIXATOR AND NUMBER OF PINS: COMPUTER ANALYSIS USING FINITE ELEMENTS

PubMed Central

Sternick, Marcelo Back; Dallacosta, Darlan; Bento, Daniela Águida; do Reis, Marcelo Lemos

2015-01-01

Objective: To analyze the rigidity of a platform-type external fixator assembly, according to different numbers of pins on each clamp. Methods: Computer simulation on a large-sized Cromus dynamic external fixator (Baumer SA) was performed using a finite element method, in accordance with the standard ASTM F1541. The models were generated with approximately 450,000 quadratic tetrahedral elements. Assemblies with two, three and four Schanz pins of 5.5 mm in diameter in each clamp were compared. Every model was subjected to a maximum force of 200 N, divided into 10 sub-steps. For the components, the behavior of the material was assumed to be linear, elastic, isotropic and homogeneous. For each model, the rigidity of the assembly and the Von Mises stress distribution were evaluated. Results: The rigidity of the system was 307.6 N/mm for two pins, 369.0 N/mm for three and 437.9 N/mm for four. Conclusion: The results showed that four Schanz pins in each clamp promoted rigidity that was 19% greater than in the configuration with three pins and 42% greater than with two pins. Higher tension occurred in configurations with fewer pins. In the models analyzed, the maximum tension occurred on the surface of the pin, close to the fixation area. PMID:27047879

A patch clamp study on reconstituted calcium permeable channels of human sperm plasma membranes.

PubMed

Ma, X H; Shi, Y L

1999-10-01

Ionic flux is thought to be important in the initiating process of gamete interaction such as acrosome reaction. However, modern electrophysiological methods, intracellular recording and patch-clamping, are difficult to approach the ion channels in mammal sperm membrane of an intact sperm due to its small size. In this work, by reconstituting the channel protein into lipid bilayer, Ca2+ channels in human spermatozoa were investigated with voltage clamp technique. Membrane proteins isolated from human sperm of 12 healthy donors were incorporated into lipid bilayer via fusion. In a cis 50//trans 10 mmol/L CaCl2 solution system, two types of channel events with similar reversal potential near the value of a perfect Ca2+ electrode, and sensitive to nifedipine and verapamil, were observed. Their unit conductance was 40 and 25 pS respectively. Percentage of channel open time was not dependent to holding potential for the former. However, for the channels of 25 pS, the percentage increased when the holding potential was changed from -20 to 100 mV. Ca(2+)-permeable channels were also detected from the spermatozoon samples of two infertile donors. Abnormal open time of these channels indicates that there are some defects in the conformation of the channel protein of infertile sperm membrane.

Peptide probes reveal a hydrophobic steric ratchet in the anthrax toxin protective antigen translocase

PubMed Central

Colby, Jennifer M.; Krantz, Bryan A.

2015-01-01

Anthrax toxin is a tripartite virulence factor produced by Bacillus anthracis during infection. Under acidic endosomal pH conditions, the toxin's protective antigen (PA) component forms a transmembrane channel in host cells. The PA channel then translocates its two enzyme components, lethal factor (LF) and edema factor (EF), into the host cytosol under the proton motive force (PMF). Protein translocation under a PMF is catalyzed by a series of nonspecific polypeptide binding sites, called clamps. A 10-residue guest/host peptide model system, KKKKKXXSXX, was used to functionally probe polypeptide-clamp interactions within wild-type PA channels. The guest residues were Thr, Ala, Leu, Phe, Tyr, and Trp. In steady-state translocation experiments, the channel blocked most tightly with peptides that had increasing amounts of nonpolar surface area. Cooperative peptide binding was observed in the Trp-containing peptide sequence but not the other tested sequences. Trp substitutions into a flexible, uncharged linker between LF amino-terminal domain and diphtheria toxin A chain expedited translocation. Therefore, peptide clamp sites in translocase channels can sense large steric features (like tryptophan) in peptides; and while these steric interactions may make a peptide translocate poorly, in the context of folded domains they can make the protein translocate more rapidly presumably via a hydrophobic steric ratchet mechanism. PMID:26363343

Spontaneous activity of isolated dopaminergic periglomerular cells of the main olfactory bulb.

PubMed

Puopolo, Michelino; Bean, Bruce P; Raviola, Elio

2005-11-01

We examined the electrophysiological properties of a population of identified dopaminergic periglomerular cells of the main olfactory bulb using transgenic mice in which catecholaminergic neurons expressed human placental alkaline phosphatase (PLAP) on the outer surface of the plasma membrane. After acute dissociation, living dopaminergic periglomerular cells were identified by a fluorescently labeled monoclonal antibody to PLAP. In current-clamp mode, dopaminergic periglomerular cells spontaneously generated action potentials in a rhythmic fashion with an average frequency of 8 Hz. The hyperpolarization-activated cation current (Ih) did not seem important for pacemaking because blocking the current with ZD 7288 or Cs+ had little effect on spontaneous firing. To investigate what ionic currents do drive pacemaking, we performed action-potential-clamp experiments using records of pacemaking as voltage command in voltage-clamp experiments. We found that substantial TTX-sensitive Na+ current flows during the interspike depolarization. In addition, substantial Ca2+ current flowed during the interspike interval, and blocking Ca2+ current hyperpolarized the neurons and stopped spontaneous firing. These results show that dopaminergic periglomerular cells have intrinsic pacemaking activity, supporting the possibility that they can maintain a tonic release of dopamine to modulate the sensitivity of the olfactory system during odor detection. Calcium entry into these neurons provides electrical drive for pacemaking as well as triggering transmitter release.

Ex-situ gas diffusion layer intrusion effect determination of polymer electrolyte membrane fuel cell flow fields

NASA Astrophysics Data System (ADS)

Haase, S.; Rauber, M.

2015-09-01

In automotive PEM fuel cell systems, one of the most important targets is to reduce the parasitic power of balance of plant components, e.g. the air supply. This can be achieved for example by decreasing air stoichiometry. However, this could lead to bad flow sharing in the fuel cell stack. Therefore the fluid distribution in the flow field has to be evaluated, understood and optimized. This work evaluates the effect of GDL intrusion on the pressure drop via ex-situ determination of GDL intrusion using CFD simulation. The intruded GDL geometries, evaluated by an optical microscope with 200 times enlargement, are transferred to pressure drop behaviors by a numerical CFD model. These results are compared to the results of the differential pressure method of mapping the pressure distribution, described in [43]. The intrusion of the GDL leads to homogeneous flow distribution up to clamping pressures of 2.5 MPa. The inhomogeneous intrusion, induced by cracked fibers that extend into the channel, dominates the flow at higher clamping pressures and leads to the exponential increase in pressure drop in the differential pressure method. For clamping pressures used in typical fuel cell applications, the results of both methods show homogeneous flow through the channels.

Space Fabrication Demonstration System

NASA Technical Reports Server (NTRS)

1977-01-01

Progress on fabrication facility (beam builder) support structure control, clamp/weld block, and welding and truss cut off is discussed. The brace attachment design was changed and the design of the weld mechanism was modified which achieved the following system benefits: (1) simplified weld electrode life; (2) reduced weld power requirements; and (3) simplified brace attachment mechanisms. Static and fatigue characteristics of spot welded 2024T3 aluminum joints are evaluated.

Sliding Clamp–DNA Interactions Are Required for Viability and Contribute to DNA Polymerase Management in Escherichia coli

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

Heltzel, J.; Scouten Ponticelli, S; Sanders, L

2009-01-01

Sliding clamp proteins topologically encircle DNA and play vital roles in coordinating the actions of various DNA replication, repair, and damage tolerance proteins. At least three distinct surfaces of the Escherichia coli {beta} clamp interact physically with the DNA that it topologically encircles. We utilized mutant {beta} clamp proteins bearing G66E and G174A substitutions ({beta}159), affecting the single-stranded DNA-binding region, or poly-Ala substitutions in place of residues 148-HQDVR-152 ({beta}148-152), affecting the double-stranded DNA binding region, to determine the biological relevance of clamp-DNA interactions. As part of this work, we solved the X-ray crystal structure of {beta}148-152, which verified that themore » poly-Ala substitutions failed to significantly alter the tertiary structure of the clamp. Based on functional assays, both {beta}159 and {beta}148-152 were impaired for loading and retention on a linear primed DNA in vitro. In the case of {beta}148-152, this defect was not due to altered interactions with the DnaX clamp loader, but rather was the result of impaired {beta}148-152-DNA interactions. Once loaded, {beta}148-152 was proficient for DNA polymerase III (Pol III) replication in vitro. In contrast, {beta}148-152 was severely impaired for Pol II and Pol IV replication and was similarly impaired for direct physical interactions with these Pols. Despite its ability to support Pol III replication in vitro, {beta}148-152 was unable to support viability of E. coli. Nevertheless, physiological levels of {beta}148-152 expressed from a plasmid efficiently complemented the temperature-sensitive growth phenotype of a strain expressing {beta}159 (dnaN159), provided that Pol II and Pol IV were inactivated. Although this strain was impaired for Pol V-dependent mutagenesis, inactivation of Pol II and Pol IV restored the Pol V mutator phenotype. Taken together, these results support a model in which a sophisticated combination of competitive clamp-DNA, clamp-partner, and partner-DNA interactions serve to manage the actions of the different E. coli Pols in vivo.« less

Effect of timing of umbilical cord clamping on anaemia at 8 and 12 months and later neurodevelopment in late pre-term and term infants; a facility-based, randomized-controlled trial in Nepal.

PubMed

Kc, Ashish; Målqvist, Mats; Rana, Nisha; Ranneberg, Linda Jarawka; Andersson, Ola

2016-03-10

Delayed cord clamping at birth has shown to benefit neonates with increased placental transfusion leading to higher haemoglobin concentrations, additional iron stores and less anaemia later in infancy, higher red blood cell flow to vital organs and better cardiopulmonary adaptation. As iron deficiency in infants even without anaemia has been associated with impaired development, delayed cord clamping seems to benefit full term infants also in regions with a relatively low prevalence of iron deficiency anaemia. In Nepal, there is a high anaemia prevalence among children between 6 and 17 months (72-78 %). The objective of the proposed study is to evaluate the effects of delayed and early cord clamping on anaemia (and haemoglobin level) at 8 and 12 months, ferritin at 8 and 12 months, bilirubin at 2-3 days, admission to Neonatal Intensive Care Unit (NICU) or special care nursery, and development at 12 and 18-24 months of age. A randomized, controlled trial comparing delayed and early cord clamping will be implemented at Paropakar Maternity and Women's Hospital in Kathmandu, Nepal. Pregnant woman of gestational age 34-41 weeks who deliver vaginally will be included in the study. The interventions will consist of delayed clamping of the umbilical cord (≥180 s after delivery) or early clamping of the umbilical cord (≤60 s). At 8 and 12 months of age, infant's iron status and developmental milestones will be measured. This trial is important to perform because, although strong indications for the beneficial effect of delayed cord clamping on anaemia at 8 to 12 months of age exist, it has not yet been evaluated by a randomized trial in this setting. The proposed study will analyse both outcome as well as safety effects. Additionally, the results may not only contribute to practice in Nepal, but also to the global community, in particular to other low-income countries with a high prevalence of iron deficiency anaemia. Clinical trial.gov NCT02222805 . Registered August 19 2014.

Voltage dependence of the rat chorda tympani response to Na+ salts: implications for the functional organization of taste receptor cells.

PubMed

Ye, Q; Heck, G L; DeSimone, J A

1993-07-01

1. Voltage-clamp and current-clamp data were obtained from a circumscribed region of the anterior rat lingual epithelium while simultaneously monitoring the afferent, stimulus-evoked, neural response from the same receptive field. 2. Chorda tympani (CT) responses at constant Na(+)-salt concentration were enhanced by submucosa negative voltage clamp and suppressed by positive voltage clamp. The complete CT response profile, including the time course of adaptation, was not uniquely determined by NaCl concentration alone. The response could be reproduced at different NaCl concentrations by applying a compensating voltage. 3. The form of the concentration and voltage dependence of the CT response indicates that the complete stimulus energy is the Na+ electrochemical potential difference across receptor cell apical membranes, and not Na+ concentration alone. This is the underlying principal behind the equivalence of chemical and electric taste for Na+ salts. 4. CT responses to sodium gluconate (25 and 200 mM) and 25 mM NaCl produced amiloride-insensitive components (AIC) of low magnitude. NaCl at 200 mM produced a significantly larger AIC. The AIC was voltage-clamp independent. The relative magnitude of the AIC was positively correlated with the transepithelial conductance of each salt. This suggests that the large AIC for 200 mM NaCl results from its relatively high permeability through the paracellular pathway. 5. Analysis of the CT response under voltage clamp revealed two anion effects on Na(+)-salt taste, both of which act through the paracellular shunt. 1) Anions modify the transepithelial potential (TP) across tight junctions and thereby modulate the cell receptor potential. This anion effect can be eliminated by voltage clamping the TP. 2) Sufficiently mobile anions facilitate electroneutral diffusion of Na+ salts through tight junctions. This effect is observed especially when Cl- is the anion and when the stimulus concentration favors NaCl influx, allowing Na+ to stimulate receptor cells from the submucosal side. Because the submucosal intercellular spaces are nearly isopotential regions, this effect is insensitive to voltage clamp of the TP. The large AIC associated with this anion effect is due to the low permeability of amiloride.

21 CFR 876.5160 - Urological clamp for males.

Code of Federal Regulations, 2010 CFR

2010-04-01

... temporarily. It is an external clamp. (b) Classification. Class I (general controls). Except when intended for internal use or use on females, the device is exempt from the premarket notification procedures in subpart...

Analytical and experimental studies of natural vibrations modes of ring-stiffened truncated-cone shells with variable theoretical ring fixity

NASA Technical Reports Server (NTRS)

Naumann, E. C.; Catherines, D. S.; Walton, W. C., Jr.

1971-01-01

Experimental and analytical investigations of the vibratory behavior of ring-stiffened truncated-cone shells are described. Vibration tests were conducted on 60 deg conical shells having up to four ring stiffeners and for free-free and clamped-free edge constraints and 9 deg conical shells, for two thicknesses, each with two angle rings and for free-free, free-clamped, and clamped-clamped edge constraints. The analytical method is based on linear thin shell theory, employing the Rayleigh-Ritz method. Discrete rings are represented as composed of one or more segments, each of which is a short truncated-cone shell of uniform thickness. Equations of constraint are used to join a ring and shell along a circumferential line connection. Excellent agreement was obtained for comparisons of experimental and calculated frequencies.

[Focus on placental transfusion for preterm neonates: Delayed cord clamping and/or milking?

PubMed

Sorin, G; Tosello, B

2016-11-01

Anemia of prematurity remains a common complication despite recent advances in perinatal and neonatal medicine. The delayed cord clamping (at least 30seconds as recommended) has several benefits: increased hemoglobin and hematocrit levels at birth, improved initial hemodynamic, decreased incidence of transfusions and intraventricular hemorrhages. When the birth transition is difficult, wait 30seconds before clamping can be impossible. So as not to interfere with the neonatal resuscitation, the "milking" has been proposed as an alternative method to the delayed cord clamping. This is a safe and easy method, which can be done either by an obstetrician or pediatrician with comparable results for the child on his hemodynamic, hematological and neurological status. It still lacks technical information on this method and neurodevelopmental outcomes of these preterm infants. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Seal assembly for materials with different coefficients of thermal expansion

DOEpatents

Minford, Eric [Laurys Station, PA

2009-09-01

Seal assembly comprising (a) two or more seal elements, each element having having a coefficient of thermal expansion; and (b) a clamping element having a first segment, a second segment, and a connecting segment between and attached to the first and second segments, wherein the two or more seal elements are disposed between the first and second segments of the clamping element. The connecting segment has a central portion extending between the first segment of the clamping element and the second segment of the clamping element, and the connecting segment is made of a material having a coefficient of thermal expansion. The coefficient of thermal expansion of the material of the connecting segment is intermediate the largest and smallest of the coefficients of thermal expansion of the materials of the two or more seal elements.

Micromachined patch-clamp apparatus

DOEpatents

Okandan, Murat

2012-12-04

A micromachined patch-clamp apparatus is disclosed for holding one or more cells and providing electrical, chemical, or mechanical stimulation to the cells during analysis with the patch-clamp technique for studying ion channels in cell membranes. The apparatus formed on a silicon substrate utilizes a lower chamber formed from silicon nitride using surface micromachining and an upper chamber formed from a molded polymer material. An opening in a common wall between the chambers is used to trap and hold a cell for analysis using the patch-clamp technique with sensing electrodes on each side of the cell. Some embodiments of the present invention utilize one or more electrostatic actuators formed on the substrate to provide mechanical stimulation to the cell being analyzed, or to provide information about mechanical movement of the cell in response to electrical or chemical stimulation.

Voltage clamp methods for the study of membrane currents and SR Ca2+ release in adult skeletal muscle fibres

PubMed Central

Hernández-Ochoa, Erick O.; Schneider, Martin F.

2012-01-01

Skeletal muscle excitation-contraction (E-C)1 coupling is a process composed of multiple sequential stages, by which an action potential triggers sarcoplasmic reticulum (SR)2 Ca2+ release and subsequent contractile activation. The various steps in the E-C coupling process in skeletal muscle can be studied using different techniques. The simultaneous recordings of sarcolemmal electrical signals and the accompanying elevation in myoplasmic Ca2+, due to depolarization-initiated SR Ca2+ release in skeletal muscle fibres, have been useful to obtain a better understanding of muscle function. In studying the origin and mechanism of voltage dependency of E-C coupling a variety of different techniques have been used to control the voltage in adult skeletal fibres. Pioneering work in muscles isolated from amphibians or crustaceans used microelectrodes or ‘high resistance gap’ techniques to manipulate the voltage in the muscle fibres. The development of the patch clamp technique and its variant, the whole-cell clamp configuration that facilitates the manipulation of the intracellular environment, allowed the use of the voltage clamp techniques in different cell types, including skeletal muscle fibres. The aim of this article is to present an historical perspective of the voltage clamp methods used to study skeletal muscle E-C coupling as well as to describe the current status of using the whole-cell patch clamp technique in studies in which the electrical and Ca2+ signalling properties of mouse skeletal muscle membranes are being investigated. PMID:22306655

Acute effect of roux-en-y gastric bypass on whole-body insulin sensitivity: a study with the euglycemic-hyperinsulinemic clamp.

PubMed

Lima, Marcelo M O; Pareja, José C; Alegre, Sarah M; Geloneze, Sylka R; Kahn, Steven E; Astiarraga, Brenno D; Chaim, Elinton A; Geloneze, Bruno

2010-08-01

Insulin resistance ameliorates after bariatric surgery, yet there is still a need for data on the acute effect of Roux-en-Y gastric bypass (RYGBP) on insulin sensitivity. The objective of the study was to describe the acute effect of RYGBP on insulin sensitivity, measured by both the euglycemic-hyperinsulinemic clamp and homeostasis model assessment insulin resistance index (HOMA-IR). Evaluations were conducted before and 1 month after RYGBP at State University of Campinas (São Paulo, Brazil). Patients included 19 premenopausal women with metabolic syndrome aged 35.3 (6.7) yr, body mass index 45.50 (3.74) kg/m2 [mean (sd)]. Six had mild type 2 diabetes, seven impaired glucose tolerance, and six normal glucose tolerance. The volunteers underwent RYGBP either alone or combined with omentectomy. Euglycemic-hyperinsulinemic clamp, HOMA-IR, nonesterified fatty acids, leptin, ultrasensitive C-reactive protein, adiponectin, and IL-6 were assessed at baseline and 4.5 (0.9) wk postoperatively. Fasting glucose decreased [99.2 (13.1) to 83.6 (8.1) mg/dl, P<0.01] along with a reduction in fasting insulin [30.4 (17.0) to 11.4 (6.3) mU/liter, P<0.01]. M value did not improve postoperatively [25.82 (6.30) to 22.02 (6.05) micromol/kgFFM.min] despite of a decrease in body weight [114.8 (14.5) to 102.3 (14.5) kg, P<0.001]. This finding was discordant to the observation of an improvement in HOMA-IR [3.85 (2.10) to 1.42 (0.76), P<0.01]. Nonesterified fatty acids increased. Leptin and C-reactive protein decreased. IL-6 and adiponectin remained unchanged. A month after RYGBP, fasting glucose metabolism improves independent of a change in peripheral insulin sensitivity.

Direct vascular control results in less physiologic derangement than proximal aortic clamping in a porcine model of noncompressible extrathoracic torso hemorrhage.

PubMed

White, Joseph M; Cannon, Jeremy W; Stannard, Adam; Burkhardt, Gabriel E; Spencer, Jerry R; Williams, Ken; Oh, John S; Rasmussen, Todd E

2011-11-01

The optimal method of vascular control and resuscitation in patients with life-threatening, extrathoracic torso hemorrhage remains debated. Guidelines recommend emergency department thoracotomy (EDT) with aortic clamping, although transabdominal aortic clamping followed by vascular control and direct vascular control (DVC) without aortic clamping are alternatives. The objective of this study is to compare the effectiveness of three approaches to extrathoracic torso hemorrhage in a large animal model. Adolescent swine (Sus Scrofa) (mean weight = 80.9 kg) were randomized into three groups all of which had class IV shock established by hemorrhage from an iliac artery injury. Group 1: EDT with thoracic aortic clamping (N = 6); group 2: transabdominal supraceliac aortic clamping (SCC; N = 6); and group 3: DVC of bleeding site without aortic clamping (N = 6). After hemorrhage, EDT or SCC was performed in groups 1 and 2, respectively, with subsequent exploration of the bleeding site and placement of a temporary vascular shunt (TVS). Group 3 (DVC) underwent direct exploration of the injury and placement of a TVS. All groups were resuscitated to predefined physiologic endpoints over 6 hours with repeated measures of central and cerebral perfusion and end-organ function at standardized time points. Postmortem tissue analysis was performed to quantify injury to critical tissue beds. There was no difference in mortality among the groups and no TVS failures. Central aortic pressure, carotid flow, and partial pressure brain tissue oximetry, all demonstrated increases in EDT and SCC after application of the aortic clamp relative to DVC (p < 0.05). During resuscitation, serum lactate levels were higher in EDT compared with SCC and DVC (6.85 vs. 3.08 and 2.15, respectively; p < 0.05) and serum pH in EDT reflected greater acidosis than SCC and DVC (7.24 vs. 7.36 and 7.39, respectively; p < 0.05). EDT and SCC required more intravenous fluid than DVC (2,166 mL and 2,166 mL vs. 667 mL, respectively; p < 0.05) and more vasopressors were used in EDT and SCC compared with DVC (52.1 μg and 43.5 μg vs. 12.4 μg, respectively; p < 0.05). Brain and myocardial tissue stains demonstrated the same degree of acute ischemic changes in all groups. Although aortic clamping increases central and cerebral perfusion, DVC results in less physiologic derangement. The optimal method of aortic control would incorporate the benefits of maintained central pressure with less associated morbidity. Clinical studies evaluating DVC are warranted.

Isolated and soft-switched power converter

DOEpatents

Peng, Fang Zheng; Adams, Donald Joe

2002-01-01

An isolated and soft-switched power converter is used for DC/DC and DC/DC/AC power conversion. The power converter includes two resonant tank circuits coupled back-to-back through an isolation transformer. Each resonant tank circuit includes a pair of resonant capacitors connected in series as a resonant leg, a pair of tank capacitors connected in series as a tank leg, and a pair of switching devices with anti-parallel clamping diodes coupled in series as resonant switches and clamping devices for the resonant leg. The power converter is well suited for DC/DC and DC/DC/AC power conversion applications in which high-voltage isolation, DC to DC voltage boost, bidirectional power flow, and a minimal number of conventional switching components are important design objectives. For example, the power converter is especially well suited to electric vehicle applications and load-side electric generation and storage systems, and other applications in which these objectives are important. The power converter may be used for many different applications, including electric vehicles, hybrid combustion/electric vehicles, fuel-cell powered vehicles with low-voltage starting, remote power sources utilizing low-voltage DC power sources, such as photovoltaics and others, electric power backup systems, and load-side electric storage and generation systems.

[Comparison of validity and safety between holmium: YAG laser and traditional surgery in partial nephrectomy].

PubMed

Bi, Sheng; Xia, Ming

2015-08-11

To compare the validity and safety between holmium: YAG laser and traditional surgery in partial nephrectomy. A total of 28 patients were divided into two groups (holmium: YAG laser group without renal artery clamping and traditional surgery group with renal artery clamping). The intraoperative blood loss, total operative time, renal artery clamping time, postoperative hospital stay, separated renal function, postoperative complications and depth of tissue injury were recorded. The intraoperative blood loss, total operative time, renal artery clamping time, postoperative hospital stay, separated renal function, postoperative complications and depth of tissue injury were 80 ml, 77 min, 0 min, 7.4 days, 35 ml/min, 0, 0.9 cm, respectively, in holmium: YAG laser group. And in traditional surgery group were 69 ml, 111 min, 25.5 min, 7.3 days, 34 ml/min, 0, 2.0 cm, respectively. The differences of total operative time, renal artery clamping time and depth of tissue injury between two groups were statistically significant. The others were not statistically significant. Holmium: YAG laser is effective and safe in partial nephrectomy. It can decrease the total operative time, minimize the warm ischemia time and enlarge the extent of surgical excision.

Comparison of detection limit in fiber-based conventional, amplified, and gain-clamped cavity ring-down techniques

NASA Astrophysics Data System (ADS)

Sharma, K.; Abdul Khudus, M. I. M.; Alam, S. U.; Bhattacharya, S.; Venkitesh, D.; Brambilla, G.

2018-01-01

Relative performance and detection limit of conventional, amplified, and gain-clamped cavity ring-down techniques (CRDT) in all-fiber configurations are compared experimentally for the first time. Refractive index measurement using evanescent field in tapered fibers is used as a benchmark for the comparison. The systematic optimization of a nested-loop configuration in gain-clamped CRDT is also discussed, which is crucial for achieving a constant gain in a CRDT experiment. It is found that even though conventional CRDT has the lowest standard error in ring-down time (Δτ), the value of ring-down time (τ) is very small, thus leading to poor detection limit. Amplified CRDT provides an improvement in τ, albeit with two orders of magnitude higher Δτ due to amplifier noise. The nested-loop configuration in gain-clamped CRDT helps in reducing Δτ by an order of magnitude as compared to amplified CRDT whilst retaining the improvement in τ. A detection limit of 1 . 03 × 10-4 RIU at refractive index of 1.322 with a 3 mm long and 4.5 μm diameter tapered fiber is demonstrated with the gain-clamped CRDT.

Mechatronic Materials and Systems. Design and Demonstration of High Aughtority Shape Morphing Structures

DTIC Science & Technology

2005-09-01

thermal expansion of these truss elements. One side of the structure is fully clamped, while the other is free to displace. As in prior assessments [6...levels, by using the finite element package ABAQUS . To simulate the complete system, the core and the Kagome face members are modeled using linear...code ABAQUS . To simulate the complete actuation system, the core and Kagome members are modeled using linear Timoshenko-type beams, while the solid

Vise holds specimens for microscope

NASA Technical Reports Server (NTRS)

Greule, W. N.

1980-01-01

Convenient, miniature, spring-loaded clamp holds specimens for scanning electron microscope. Clamp is made out of nesting sections of studded angle-aluminum. Specimens are easier to mount and dismount with vise than with conductive adhesive or paint.

Portable hand hold device

NASA Technical Reports Server (NTRS)

Redmon, Jr., John W. (Inventor); McQueen, Donald H. (Inventor); Sanders, Fred G. (Inventor)

1990-01-01

A hand hold device (A) includes a housing (10) having a hand hold (14) and clamping brackets (32,34) for grasping and handling an object. A drive includes drive lever (23), spur gear (22), and rack gears (24,26) carried on rods (24a, 26a) for moving the clamping brackets. A lock includes ratchet gear (40) and pawl (42) biased between lock and unlock positions by a cantilever spring (46,48) and moved by handle (54). Compliant grip pads (32b, 34b) provide compliance to lock, unlock, and hold an object between the clamp brackets.

Postbuckling analysis of shear deformable composite flat panels taking into account geometrical imperfections

NASA Technical Reports Server (NTRS)

Librescu, L.; Stein, M.

1990-01-01

The effects of initial geometrical imperfections on the postbuckling response of flat laminated composite panels to uniaxial and biaxial compressive loading are investigated analytically. The derivation of the mathematical model on the basis of first-order transverse shear deformation theory is outlined, and numerical results for perfect and imperfect, single-layer and three-layer square plates with free-free, clamped-clamped, or free-clamped edges are presented in graphs and briefly characterized. The present approach is shown to be more accurate than analyses based on the classical Kirchhoff plate model.

Focal Urethral Stricturing Following Intraurethral Mitomycin-C Gel and the Use of a Penile Clamp

PubMed Central

Stanford, Richard F. J.; Thomas, Stephen A.

2012-01-01

We present a case of a 51-year-old gentleman, previously diagnosed with high-grade superficial transitional cell carcinoma of the bladder and treated with intravesical mitomycin C and BCG, who developed serial recurrences in the prostatic urethra. This was resected and treated further with intraurethral mitomycin-C gel. He subsequently developed an almost impassable distal penile urethral stricture, corresponding to the site of penile clamp application which we hypothesise is secondary to a combination of the mitomycin-C gel and penile clamp pressure. PMID:22830069

Focal urethral stricturing following intraurethral mitomycin-C gel and the use of a penile clamp.

PubMed

Stanford, Richard F J; Thomas, Stephen A

2012-01-01

We present a case of a 51-year-old gentleman, previously diagnosed with high-grade superficial transitional cell carcinoma of the bladder and treated with intravesical mitomycin C and BCG, who developed serial recurrences in the prostatic urethra. This was resected and treated further with intraurethral mitomycin-C gel. He subsequently developed an almost impassable distal penile urethral stricture, corresponding to the site of penile clamp application which we hypothesise is secondary to a combination of the mitomycin-C gel and penile clamp pressure.

Electrophysiological and Electrochemical Methods Development for the Detection of Biologically Active Chemical Agents

DTIC Science & Technology

1988-11-01

Bilayer ........................................... 14 5. Current-Voltage Curve for Gramacidin in a Lecithin -Sphingomyelin Patch Bilayer... lecithin (Avanti). 9 2. MATERIALS 2.1 Patch Microprobe Instrumentation. The basis of the microprobe system is an AxoPatch Patch- Clamping Amplifier System...histogram of 1024 events cut above 2 pA. Events sampled are thought to be from the same single gramacidin channel in a lecithin : sphingomyelin (5:1) patch

A wide bandwidth electrostatic field sensor for lightning research

NASA Technical Reports Server (NTRS)

Zaepfel, K. P.

1986-01-01

Data obtained from UHF Radar observation of direct-lightning strikes to the NASA F-106B airplane have indicated that most of the 690 strikes acquired during direct-strike lightning tests were triggered by the aircraft. As an aid in understanding the triggered lightning process, a wide bandwidth electric field measuring system was designed for the F-106B by implementing a clamped-detection signal processing concept originated at the Air Force Cambridge Research Lab in 1953. The detection scheme combines the signals from complementary stator pairs clamped to zero volts at the exact moment when each stator pair is maximally shielded by the rotor, a process that restores the dc level lost by the charge amplifier. The new system was implemented with four shutter-type field mills located at strategic points on the airplane. The bandwidth of the new system was determined in the laboratory to be from dc to over 100 Hz, whereas past designs had upper limits of 10 Hz to 100 Hz. To obtain the undisturbed electric field vector and total aircraft charge, the airborne field mill system is calibrated by using techniques involving results from ground and flight calibrations of the F-106B, laboratory tests of a metallized model, and a finite-difference time-domain electromagnetic computer code.

A wide bandwidth electrostatic field sensor for lightning research

NASA Technical Reports Server (NTRS)

Zaepfel, Klaus P.

1989-01-01

Data obtained from UHF radar observation of direct-lightning strikes to the NASA F-106B aircraft have indicated that most of the 690 strikes acquired during direct-strike lightning tests were triggered by the aircraft. As an aid in understanding the triggered lightning process, a wide bandwidth electric field measuring system was designed for the F-106B by implementing a clamped-detection signal processing concept originated at the Air Force Cambridge Research Lab in 1953. The detection scheme combines the signals from complementary stator pairs clamped to zero bolts at the exact moment when each stator pair is maximally shielded by the rotor, a process that restores the dc level lost by the charge amplifier. The system was implemented with four shutter-type field mills located at strategic points on the aircraft. The bandwidth of the system was determined in the laboratory to be from dc to over 100 Hz, whereas past designs had upper limits of 10 to 100 Hz. To obtain the undisturbed electric field vector and total aircraft charge, the airborne field mill system is calibrated by using techniques involving results from ground and flight calibrations of the F-106B, laboratory tests of a metallized model, and a finite difference time-domain electromagnetic computer code.

Validity and reproducibility of HOMA-IR, 1/HOMA-IR, QUICKI and McAuley's indices in patients with hypertension and type II diabetes.

PubMed

Sarafidis, P A; Lasaridis, A N; Nilsson, P M; Pikilidou, M I; Stafilas, P C; Kanaki, A; Kazakos, K; Yovos, J; Bakris, G L

2007-09-01

The aim of this study was to evaluate the validity and reliability of homeostasis model assessment-insulin resistance (HOMA-IR) index, its reciprocal (1/HOMA-IR), quantitative insulin sensitivity check index (QUICKI) and McAuley's index in hypertensive diabetic patients. In 78 patients with hypertension and type II diabetes glucose, insulin and triglyceride levels were determined after a 12-h fast to calculate these indices, and insulin sensitivity (IS) was measured with the hyperinsulinemic euglycemic clamp technique. Two weeks later, subjects had again their glucose, insulin and triglycerides measured. Simple and multiple linear regression analysis were applied to assess the validity of these indices compared to clamp IS and coefficients of variation between the two visits were estimated to assess their reproducibility. HOMA-IR index was strongly and inversely correlated with the basic IS clamp index, the M-value (r=-0.572, P<0.001), M-value normalized with subjects' body weight or fat-free mass and every other clamp-derived index. 1/HOMA-IR and QUICKI indices were positively correlated with the M-value (r=0.342, P<0.05 and r=0.456, P<0.01, respectively) and the rest clamp indices. McAuley's index generally presented less strong correlations (r=0.317, P<0.05 with M-value). In multivariate analysis, HOMA-IR was the best fit of clamp-derived IS. Coefficients of variation between the two visits were 23.5% for HOMA-IR, 19.2% for 1/HOMA-IR, 7.8% for QUICKI and 15.1% for McAuley's index. In conclusion, HOMA-IR, 1/HOMA-IR and QUICKI are valid estimates of clamp-derived IS in patients with hypertension and type II diabetes, whereas the validity of McAuley's index needs further evaluation. QUICKI displayed better reproducibility than the other indices.

Assessment of the Dynamic Insulin Secretion and Sensitivity Test (DISST) Pre and Post Gastric bypass Surgery.

PubMed

Wilson, John; Docherty, Paul; Stubbs, Richard; Chase, J Geoffrey; Krebs, Jeremy

2018-06-11

To compare the dynamic insulin secretion and sensitivity test (DISST) with the euglycaemic clamp in individuals undergoing open Roux-en-Y gastric bypass (RYGB) surgery prior-to and one month after surgery. Insulin sensitivity in individuals with obesity undergoing RYGB was studied with DISST and a euglycaemic hyperinsulinaemic clamp. Eleven participants, including nine females, mean(SD) age 51.2(12.1)yrs, with a preoperative BMI of 48.7(9.5)kg/m 2 were studied. Weight reduced from a mean(SD) of 133.8(29.8)kg to 123.8(28.9)kg post-surgery (p<0.001). The mean(SD) insulin sensitivity index (ISI-DISST) was 3.07×10 -4 (2.18)L.pmol -1 .min -1 preoperatively and 2.36 ×10 -4 (0.78)L.pmol -1 .min -1 postoperatively (p=0.37). The mean(SD) clamp ISI was 2.14 ×10 -2 (1.80)mg.L.kg -1 .min -1 .pmol -1 and 2.00×10 -2 .(0.76)mg.L.kg -1 .min -1 .pmol -1 postoperatively (p=0.86). Correlation between ISI-DISST and ISI-Clamp preoperatively was r=0.81(95%CI 0.37-0.95) and post-operatively r=0.47(95%CI 0-0.88). Bland-Altman analysis demonstrates systematic bias between the two tests, where DISST underestimated insulin sensitivity compared with the clamp by 0.96×10 -2 .mg.L.kg -1 .min -1 .pmol -1 (95%CI -2.24 to 0.32). There was a strong correlation between DISST and the clamp preoperatively and DISST can be used to estimate insulin sensitivity in individuals with morbid obesity. After RYGB surgery, DISST had a weaker correlation with the clamp suggesting the fundamental physiological determinants of insulin sensitivity being measured by each method change in different ways with changes in glucose homeostasis following RYGB surgery. © Georg Thieme Verlag KG Stuttgart · New York.

Impact of delayed umbilical cord clamping on public cord blood donations: can we help future patients and benefit infant donors?

PubMed

Ciubotariu, Rodica; Scaradavou, Andromachi; Ciubotariu, Ilinca; Tarnawski, Michal; Lloyd, Sara; Albano, Maria; Dobrila, Ludy; Rubinstein, Pablo; Grunebaum, Amos

2018-03-25

Cord blood (CB) is a widely accepted stem cell source and its clinical utilization depends, to a great extent, on its cell content. Birth-to-clamping (BTC) time of umbilical cord determines placental transfusion to the newborn, and the remaining blood that can be collected and banked. The 2017 Committee Opinion of the American College of Obstetrics and Gynecologists (ACOG) recommends a delay of "at least 30-60 seconds" before clamping the cord for all newborns to ensure adequate iron stores. The impact of delayed cord clamping (DCC) on public CB banking can be substantial. Cord blood units (CBUs) collected from 1210 mothers at one hospital were evaluated for total nucleated cells (TNCs) and weight/volume based on time to clamping. Bank staff recorded BTC time in seconds as reported by obstetricians; collections were performed ex utero. Immediate clamping was defined as BTC of less than 30 seconds, whereas DCC was defined as BTC of 30 seconds or more. Cord clamping was immediate in 903 (75%) and delayed in 307 (25%) deliveries. Successful recovery (% clinical CBUs) decreased 10-fold with DCC of more than 60 seconds (22% vs. 2.4%, p < 0.001). CBUs collected after DCC of more than 60 seconds had significantly lower TNC counts than those after DCC of less than 60 seconds (p < 0.0001). Furthermore, 38% to 46% of CBUs after DCC of more than 60 seconds had volume of less than 40 mL. Our study indicates that DCC of 30 to 60 seconds has a small negative impact on collection of high-TNC-count CBUs. However, increasing BTC to more than 60 seconds decreases significantly both TNC content and volume, reducing drastically the chances of obtaining clinically useful CBUs. © 2018 AABB.

Portable Roller Staking Tool

NASA Technical Reports Server (NTRS)

Bird, R. G.; Berson, L. A.

1983-01-01

Staking tool compact and portable. Tool combines clamping and staking operations in single unit. Tool clamps workpiece (a bearing or bushing), alines it, and stakes on of flat faces. Used for most roller staking operations which acess both faces of workpiece.

A monogenean without clamps

USDA-ARS?s Scientific Manuscript database

Ectoparasites face a daily challenge: to remain attached to their host. Polyopisthocotylean monogeneans attach to the surface of fish gills by highly specialized structures, the sclerotized clamps. In the original description of the protomicrocotylid species Lethacotyle fijiensis, described 50 years...

Knife-edge seal for vacuum bagging

NASA Technical Reports Server (NTRS)

Rauschl, J. A.

1980-01-01

Cam actuated clamps pinch bagging material between long knife edge (mounted to clamps) and high temperature rubber cushion bonded to baseplate. No adhesive, tape, or sealing groove is needed to seal edge of bagging sheet against base plate.

[Advantage of delayed umbilical cord clamping in the newborn infant].

PubMed

Menget, A; Mougey, C; Thiriez, G; Riethmuller, D

2013-09-01

The timing of umbilical cord clamping remains controversial. Although most maternity wards use the early clamping (5-15s), randomized studies and meta-analyses have demonstrated the benefit of delayed clamping for term and preterm newborn infants over the past 10 years. Indeed, placentofetal transfusion of 20-30 ml/kg in 2-3 min improves the iron status of term infants and prevents infant hypochromic anemia. Infant anemia is a public health problem in many developing countries. For preterm newborns, placental transfusion for 45 s or milking the cord for 15 s improves cardiovascular adaptation, with better hemodynamic stability, as well as decreased intraventricular hemorrhages, need for transfusion, and late-onset sepsis. A new look at this symbolic act is needed and professionals need to be persuaded of the importance of the "wait a minute" policy for a better physiological delivery. Copyright © 2013. Published by Elsevier SAS.

Microgravity condensing heat exchanger

NASA Technical Reports Server (NTRS)

Thomas, Christopher M. (Inventor); Ma, Yonghui (Inventor); North, Andrew (Inventor); Weislogel, Mark M. (Inventor)

2011-01-01

A heat exchanger having a plurality of heat exchanging aluminum fins with hydrophilic condensing surfaces which are stacked and clamped between two cold plates. The cold plates are aligned radially along a plane extending through the axis of a cylindrical duct and hold the stacked and clamped portions of the heat exchanging fins along the axis of the cylindrical duct. The fins extend outwardly from the clamped portions along approximately radial planes. The spacing between fins is symmetric about the cold plates, and are somewhat more closely spaced as the angle they make with the cold plates approaches 90.degree.. Passageways extend through the fins between vertex spaces which provide capillary storage and communicate with passageways formed in the stacked and clamped portions of the fins, which communicate with water drains connected to a pump externally to the duct. Water with no entrained air is drawn from the capillary spaces.

Large-deflection theory for end compression of long rectangular plates rigidly clamped along two edges

NASA Technical Reports Server (NTRS)

Levy, Samuel; Krupen, Philip

1943-01-01

The von Karman equations for flat plates are solved beyond the buckling load up to edge strains equal to eight time the buckling strain, for the extreme case of rigid clamping along the edges parallel to the load. Deflections, bending stresses, and membrane stresses are given as a function of end compressive load. The theoretical values of effective width are compared with the values derived for simple support along the edges parallel to the load. The increases in effective width due to rigid clamping drops from about 20 percent near the buckling strain to about 8 percent at an edge strain equal to eight times the buckling strain. Experimental values of effective width in the elastic range reported in NACA Technical Note No. 684 are between the theoretical curves for the extremes of simple support and rigid clamping.

Testing of New Materials and Computer Aided Optimization of Process Parameters and Clamping Device During Predevelopment of Laser Welding Processes

NASA Astrophysics Data System (ADS)

Weidinger, Peter; Günther, Kay; Fitzel, Martin; Logvinov, Ruslan; Ilin, Alexander; Ploshikhin, Vasily; Hugger, Florian; Mann, Vincent; Roth, Stephan; Schmidt, Michael

The necessity for weight reduction in motor vehicles in order to save fuel consumption pushes automotive suppliers to use materials of higher strength. Due to their excellent crash behavior high strength steels are increasingly applied in various structures. In this paper some predevelopment steps for a material change from a micro alloyed to dual phase and complex phase steels of a T-joint assembly are displayed. Initially the general weldability of the materials regarding pore formation, hardening in the heat affected zone and hot cracking susceptibility is discussed. After this basic investigation, the computer aided design optimization of a clamping device is shown, in which influences of the clamping jaw, the welding position and the clamping forces upon weld quality are presented. Finally experimental results of the welding process are displayed, which validate the numerical simulation.

Functional Evaluation of Biological Neurotoxins in Networked Cultures of Stem Cell-derived Central Nervous System Neurons

DTIC Science & Technology

2015-02-05

botulism or tetanus , whole-cell patch clamp electrophysiology was used to quantify spontaneous miniature excitory post-synaptic currents (mEPSCs) in...ESNs exposed to tetanus neurotoxin (TeNT) or botulinum neurotoxin (BoNT) serotypes / A-/G. In all cases, ESNs exhibited near-complete loss of synaptic

76 FR 13661 - In the Matter of Certain Connecting Devices (“Quick Clamps”) for Use With Modular Compressed Air...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-14

... INTERNATIONAL TRADE COMMISSION [Investigation No. 337-TA-587] In the Matter of Certain Connecting Devices (``Quick Clamps'') for Use With Modular Compressed Air Conditioning Units, Including Filters, Regulators, and Lubricators (``FRL's'') That Are Part of Larger Pneumatic Systems and the FRL Units They...

75 FR 63198 - In the Matter of Certain Connecting Devices (“Quick Clamps”) for Use With Modular Compressed Air...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-14

... INTERNATIONAL TRADE COMMISSION [Investigation No. 337-TA-587] In the Matter of Certain Connecting Devices (``Quick Clamps'') for Use With Modular Compressed Air Conditioning Units, Including Filters, Regulators, and Lubricators (``Frl's'') That Are Part of Larger Pneumatic Systems and the FRL Units They...

Patch-clamp recordings of rat neurons from acute brain slices of the somatosensory cortex during magnetic stimulation

PubMed Central

Pashut, Tamar; Magidov, Dafna; Ben-Porat, Hana; Wolfus, Shuki; Friedman, Alex; Perel, Eli; Lavidor, Michal; Bar-Gad, Izhar; Yeshurun, Yosef; Korngreen, Alon

2014-01-01

Although transcranial magnetic stimulation (TMS) is a popular tool for both basic research and clinical applications, its actions on nerve cells are only partially understood. We have previously predicted, using compartmental modeling, that magnetic stimulation of central nervous system neurons depolarized the soma followed by initiation of an action potential in the initial segment of the axon. The simulations also predict that neurons with low current threshold are more susceptible to magnetic stimulation. Here we tested these theoretical predictions by combining in vitro patch-clamp recordings from rat brain slices with magnetic stimulation and compartmental modeling. In agreement with the modeling, our recordings demonstrate the dependence of magnetic stimulation-triggered action potentials on the type and state of the neuron and its orientation within the magnetic field. Our results suggest that the observed effects of TMS are deeply rooted in the biophysical properties of single neurons in the central nervous system and provide a framework both for interpreting existing TMS data and developing new simulation-based tools and therapies. PMID:24917788

Sodium and potassium conductance changes during a membrane action potential.

PubMed

Bezanilla, F; Rojas, E; Taylor, R E

1970-12-01

1. A method for turning a membrane potential control system on and off in less than 10 musec is described. This method was used to record membrane currents in perfused giant axons from Dosidicus gigas and Loligo forbesi after turning on the voltage clamp system at various times during the course of a membrane action potential.2. The membrane current measured just after the capacity charging transient was found to have an almost linear relation to the controlled membrane potential.3. The total membrane conductance taken from these current-voltage curves was found to have a time course during the action potential similar to that found by Cole & Curtis (1939).4. The instantaneous current voltage curves were linear enough to make it possible to obtain a good estimate of the individual sodium and potassium channel conductances, either algebraically or by clamping to the sodium, or potassium, reversal potentials. Good general agreement was obtained with the predictions of the Hodgkin-Huxley equations.5. We consider these results to constitute the first direct experimental demonstration of the conductance changes to sodium and potassium during the course of an action potential.

Introduction to Solid Supported Membrane Based Electrophysiology

PubMed Central

Bazzone, Andre; Costa, Wagner Steuer; Braner, Markus; Călinescu, Octavian; Hatahet, Lina; Fendler, Klaus

2013-01-01

The electrophysiological method we present is based on a solid supported membrane (SSM) composed of an octadecanethiol layer chemisorbed on a gold coated sensor chip and a phosphatidylcholine monolayer on top. This assembly is mounted into a cuvette system containing the reference electrode, a chlorinated silver wire. After adsorption of membrane fragments or proteoliposomes containing the membrane protein of interest, a fast solution exchange is used to induce the transport activity of the membrane protein. In the single solution exchange protocol two solutions, one non-activating and one activating solution, are needed. The flow is controlled by pressurized air and a valve and tubing system within a faraday cage. The kinetics of the electrogenic transport activity is obtained via capacitive coupling between the SSM and the proteoliposomes or membrane fragments. The method, therefore, yields only transient currents. The peak current represents the stationary transport activity. The time dependent transporter currents can be reconstructed by circuit analysis. This method is especially suited for prokaryotic transporters or eukaryotic transporters from intracellular membranes, which cannot be investigated by patch clamp or voltage clamp methods. PMID:23711952

Introduction to solid supported membrane based electrophysiology.

PubMed

Bazzone, Andre; Costa, Wagner Steuer; Braner, Markus; Călinescu, Octavian; Hatahet, Lina; Fendler, Klaus

2013-05-11

The electrophysiological method we present is based on a solid supported membrane (SSM) composed of an octadecanethiol layer chemisorbed on a gold coated sensor chip and a phosphatidylcholine monolayer on top. This assembly is mounted into a cuvette system containing the reference electrode, a chlorinated silver wire. After adsorption of membrane fragments or proteoliposomes containing the membrane protein of interest, a fast solution exchange is used to induce the transport activity of the membrane protein. In the single solution exchange protocol two solutions, one non-activating and one activating solution, are needed. The flow is controlled by pressurized air and a valve and tubing system within a faraday cage. The kinetics of the electrogenic transport activity is obtained via capacitive coupling between the SSM and the proteoliposomes or membrane fragments. The method, therefore, yields only transient currents. The peak current represents the stationary transport activity. The time dependent transporter currents can be reconstructed by circuit analysis. This method is especially suited for prokaryotic transporters or eukaryotic transporters from intracellular membranes, which cannot be investigated by patch clamp or voltage clamp methods.

Chaotic non-planar vibrations of the thin elastica. Part I: Experimental observation of planar instability

NASA Astrophysics Data System (ADS)

Cusumano, J. P.; Moon, F. C.

1995-01-01

In this two-part paper, the results of an investigation into the non-linear dynamics of a flexible cantilevered rod (the elastica) with a thin rectangular cross-section are presented. An experimental examination of the dynamics of the elastica over a broad parameter range forms the core of Part I. In Part II, the experimental work is related to a theoretical study of the mechanics of the elastica, and the study of a two-degree-of-freedom model obtained by modal projection. The experimental system used in this investigation is a rod with clamped-free boundary conditions, forced by sinusoidally displacing the clamped end. Planar periodic motions of the driven elastica are shown to lose stability at distinct resonant wedges, and the resulting motions are shown in general to be non-planar, chaotic, bending-torsion oscillations. Non-planar motions in all resonances exhibit energy cascading and dynamic two-well phenomena, and a family of asymmetric, bending-torsion non-linear modes is discovered. Correlation dimension calculations are used to estimate the number of active degrees of freedom in the system.

Pipe support for use in a nuclear system

DOEpatents

Pollono, Louis P.; Mello, Raymond M.

1977-01-01

A pipe support for high temperature, thin-walled vertical piping runs used in a nuclear system. A cylindrical pipe transition member, having the same inside diameter as the thin-walled piping, replaces a portion of the piping where support is desired. The outside diameter of the pipe transition member varies axially along its vertical dimension. For a section of the axial length adjacent the upper and lower terminations of the pipe transition member, the outside diameter is the same as the outside diameter of the thin-walled piping to which it is affixed. Intermediate of the termination sections, the outside diameter increases from the top of the member to the bottom. Adjacent the lower termination section, the diameter abruptly becomes the same as the piping. Thus, the cylindrical transition member is formed to have a generally triangular shaped cross-section along the axial dimension. Load-bearing insulation is installed next to the periphery of the member and is kept in place by an outer ring clamp. The outer ring clamp is connected to pipe hangers, which provide the desired support for the vertical thin-walled piping runs.

Effect of bottle height and aspiration rate on postocclusion surge in Infiniti and Millennium peristaltic phacoemulsification machines.

PubMed

Ward, Matthew S; Georgescu, Dan; Olson, Randall J

2008-08-01

To assess how flow and bottle height affect postocclusion surge in the Infiniti (Alcon, Inc.) and Millennium (Bausch & Lomb) peristaltic machines. John A. Moran Eye Center Clinical Laboratories, University of Utah, Salt Lake City, Utah. Postocclusion anterior chamber depth changes were measured in human eye-bank eyes using A-scan. Surge was simulated by clamping the aspiration tubing and releasing it at maximum vacuum. In both machines, surge was measured (1) with aspiration held constant at 12 mL/min and bottle heights at 60, 120, and 180 cm and (2) with bottle height held constant at 60 cm and aspiration rates at 12, 24, and 36 mL/min. Surge decreased approximately 40% with each 60 cm increase in bottle height in the Infiniti. It was constant at all bottle heights in the Millennium. At 12 and 24 mL/min aspiration rates, surge in the Millennium was less than half that in the Infiniti (P<.001). Postocclusion surge decreased linearly with increasing bottle height in the Infiniti system and was relatively constant with increasing bottle height in the Millennium system. The Millennium may offer a more stable phacoemulsification platform with respect to surge at a higher aspiration rate.

Estimating the Cost of Early Infant Male Circumcision in Zimbabwe: Results From a Randomized Noninferiority Trial of AccuCirc Device Versus Mogen Clamp.

PubMed

Mangenah, Collin; Mavhu, Webster; Hatzold, Karin; Biddle, Andrea K; Madidi, Ngonidzashe; Ncube, Getrude; Mugurungi, Owen; Ticklay, Ismail; Cowan, Frances M; Thirumurthy, Harsha

2015-08-15

Safe and cost-effective programs for implementing early infant male circumcision (EIMC) in Africa need to be piloted. We present results on a relative cost analysis within a randomized noninferiority trial of EIMC comparing the AccuCirc device with Mogen clamp in Zimbabwe. Between January and June 2013, male infants who met inclusion criteria were randomized to EIMC through either AccuCirc or Mogen clamp conducted by a doctor, using a 2:1 allocation ratio. We evaluated the overall unit cost plus the key cost drivers of EIMC using both AccuCirc and Mogen clamp. Direct costs included consumable and nonconsumable supplies, device, personnel, associated staff training, and environmental costs. Indirect costs comprised capital and support personnel costs. In 1-way sensitivity analyses, we assessed potential changes in unit costs due to variations in main parameters, one at a time, holding all other values constant. The unit costs of EIMC using AccuCirc and Mogen clamp were $49.53 and $55.93, respectively. Key cost drivers were consumable supplies, capacity utilization, personnel costs, and device price. Unit prices are likely to be lowest at full capacity utilization and increase as capacity utilization decreases. Unit prices also fall with lower personnel salaries and increase with higher device prices. EIMC has a lower unit cost when using AccuCirc compared with Mogen clamp. To minimize unit costs, countries planning to scale-up EIMC using AccuCirc need to control costs of consumables and personnel. There is also need to negotiate a reasonable device price and maximize capacity utilization.

Role of the α clamp in the protein translocation mechanism of anthrax toxin

PubMed Central

Brown, Michael J.; Thoren, Katie L.; Krantz, Bryan A.

2015-01-01

Membrane-embedded molecular machines are utilized to move water-soluble proteins across these barriers. Anthrax toxin forms one such machine through the self-assembly of its three component proteins—protective antigen (PA), lethal factor (LF), and edema factor (EF). Upon endocytosis into host cells, acidification of the endosome induces PA to form a membrane-inserted channel, which unfolds LF and EF and translocates them into the host cytosol. Translocation is driven by the proton motive force, comprised of the chemical potential, the proton-gradient (ΔpH), and the membrane potential (ΔΨ). A crystal structure of the lethal toxin core complex revealed an “α clamp” structure that binds to substrate helices nonspecifically. Here we test the hypothesis that through the recognition of unfolding helical structure the α clamp can accelerate the rate of translocation. We produced a synthetic PA mutant in which an α helix was crosslinked into the α clamp to block its function. This synthetic construct impairs translocation by raising a yet uncharacterized translocation barrier shown to be much less force dependent than the known unfolding barrier. We also report that the α clamp more stably binds substrates that can form helices than those, such as polyproline, that cannot. Hence the α clamp recognizes substrates by a general shape-complementarity mechanism. Substrates that are incapable of forming compact secondary structure (due to the introduction of a polyproline track) are severely deficient for translocation. Therefore, the α clamp and its recognition of helical structure in the translocating substrate play key roles in the molecular mechanism of protein translocation. PMID:26344833

The Relationship between Oxygen Saturation and Color Alteration of a Compromised Skin Flap: Experimental Study on the Rabbit.

PubMed

Prasetyono, Theddeus O H; Adianto, Senja

2013-09-01

The aim of this study was to collect important data on the time of oxygen saturation change in relation to skin flap color alteration using non-invasive pulse oximetry to evaluate its ability to provide continuous monitoring of skin flap perfusion. An experimental study on the monitoring of blood perfusion of 20 tube-island groin flaps of 10 male New Zealand rabbits was performed using pulse oximetry. The animals were randomly assigned to one of two groups representing a blockage of either arterial or venous blood flow. The oxygen saturation change and clinical color alteration were monitored from the beginning of vessel clamping until the saturation became undetectable. The result was analyzed by the t-test using SSPS ver. 10.0. The mean times from the vessel clamping until the saturation became undetectable were 20.19±2.13 seconds and 74.91±10.57 seconds for the artery and vein clamping groups, respectively. The mean time of the clinical alteration from the beginning of vein clamping was 34.5±11.72 minutes, while the alteration in flaps with artery clamping could not be detected until 2.5 hours after clamping. The use of neonate-type reusable flex sensor-pulse oximetry is objective and effective in early detection of arterial and vein blockage. It provides real-time data on vessel occlusion, which in turn will allow for early salvaging. The detection periods of both arterial occlusion and venous congestion are much earlier than the color alteration one may encounter clinically.

Thermodynamic basis for engineering high-affinity, high-specificity binding-induced DNA clamp nanoswitches.

PubMed

Idili, Andrea; Plaxco, Kevin W; Vallée-Bélisle, Alexis; Ricci, Francesco

2013-12-23

Naturally occurring chemoreceptors almost invariably employ structure-switching mechanisms, an observation that has inspired the use of biomolecular switches in a wide range of artificial technologies in the areas of diagnostics, imaging, and synthetic biology. In one mechanism for generating such behavior, clamp-based switching, binding occurs via the clamplike embrace of two recognition elements onto a single target molecule. In addition to coupling recognition with a large conformational change, this mechanism offers a second advantage: it improves both affinity and specificity simultaneously. To explore the physics of such switches we have dissected here the thermodynamics of a clamp-switch that recognizes a target DNA sequence through both Watson-Crick base pairing and triplex-forming Hoogsteen interactions. When compared to the equivalent linear DNA probe (which relies solely on Watson-Crick interactions), the extra Hoogsteen interactions in the DNA clamp-switch increase the probe's affinity for its target by ∼0.29 ± 0.02 kcal/mol/base. The Hoogsteen interactions of the clamp-switch likewise provide an additional specificity check that increases the discrimination efficiency toward a single-base mismatch by 1.2 ± 0.2 kcal/mol. This, in turn, leads to a 10-fold improvement in the width of the "specificity window" of this probe relative to that of the equivalent linear probe. Given these attributes, clamp-switches should be of utility not only for sensing applications but also, in the specific field of DNA nanotechnology, for applications calling for a better control over the building of nanostructures and nanomachines.

A computer-based servo system for controlling isotonic contractions of muscle.

PubMed

Smith, J P; Barsotti, R J

1993-11-01

We have developed a computer-based servo system for controlling isotonic releases in muscle. This system is a composite of commercially available devices: an IBM personal computer, an analog-to-digital (A/D) board, an Akers AE801 force transducer, and a Cambridge Technology motor. The servo loop controlling the force clamp is generated by computer via the A/D board, using a program written in QuickBASIC 4.5. Results are shown that illustrate the ability of the system to clamp the force generated by either skinned cardiac trabeculae or single rabbit psoas fibers down to the resolution of the force transducer within 4 ms. This rate is independent of the level of activation of the tissue and the size of the load imposed during the release. The key to the effectiveness of the system consists of two algorithms that are described in detail. The first is used to calculate the error signal to hold force to the desired level. The second algorithm is used to calculate the appropriate gain of the servo for a particular fiber and the size of the desired load to be imposed. The results show that the described computer-based method for controlling isotonic releases in muscle represents a good compromise between simplicity and performance and is an alternative to the custom-built digital/analog servo devices currently being used in studies of muscle mechanics.

A Literature Review of Renal Surgical Anatomy and Surgical Strategies for Partial Nephrectomy

PubMed Central

Klatte, Tobias; Ficarra, Vincenzo; Gratzke, Christian; Kaouk, Jihad; Kutikov, Alexander; Macchi, Veronica; Mottrie, Alexandre; Porpiglia, Francesco; Porter, James; Rogers, Craig G.; Russo, Paul; Thompson, R. Houston; Uzzo, Robert G.; Wood, Christopher G.; Gill, Inderbir S.

2016-01-01

Context A detailed understanding of renal surgical anatomy is necessary to optimize preoperative planning and operative technique and provide a basis for improved outcomes. Objective To evaluate the literature regarding pertinent surgical anatomy of the kidney and related structures, nephrometry scoring systems, and current surgical strategies for partial nephrectomy (PN). Evidence acquisition A literature review was conducted. Evidence synthesis Surgical renal anatomy fundamentally impacts PN surgery. The renal artery divides into anterior and posterior divisions, from which approximately five segmental terminal arteries originate. The renal veins are not terminal. Variations in the vascular and lymphatic channels are common; thus, concurrent lymphadenectomy is not routinely indicated during PN for cT1 renal masses in the setting of clinically negative lymph nodes. Renal-protocol contrast-enhanced computed tomography or magnetic resonance imaging is used for standard imaging. Anatomy-based nephrometry scoring systems allow standardized academic reporting of tumor characteristics and predict PN outcomes (complications, remnant function, possibly histology). Anatomy-based novel surgical approaches may reduce ischemic time during PN; these include early unclamping, segmental clamping, tumor-specific clamping (zero ischemia), and unclamped PN. Cancer cure after PN relies on complete resection, which can be achieved by thin margins. Post-PN renal function is impacted by kidney quality, remnant quantity, and ischemia type and duration. Conclusions Surgical renal anatomy underpins imaging, nephrometry scoring systems, and vascular control techniques that reduce global renal ischemia and may impact post-PN function. A contemporary ideal PN excises the tumor with a thin negative margin, delicately secures the tumor bed to maximize vascularized remnant parenchyma, and minimizes global ischemia to the renal remnant with minimal complications. Patient summary In this report we review renal surgical anatomy. Renal mass imaging allows detailed delineation of the anatomy and vasculature and permits nephrometry scoring, and thus precise, patient-specific surgical planning. Novel off-clamp techniques have been developed that may lead to improved outcomes. PMID:25911061

A micro-coupling for micro mechanical systems

NASA Astrophysics Data System (ADS)

Li, Wei; Zhou, Zhixiong; Zhang, Bi; Xiao, Yunya

2016-05-01

The error motions of micro mechanical systems, such as micro-spindles, increase with the increasing of the rotational speed, which not only decreases the rotational accuracy, but also promotes instability and limits the maximum operational speed. One effective way to deal with it is to use micro-flexible couplings between the drive and driven shafts so as to reduce error motions of the driven shaft. But the conventional couplings, such as diaphragm couplings, elastomeric couplings, bellows couplings, and grooved couplings, etc, cannot be directly used because of their large and complicated structures. This study presents a novel micro-coupling that consists of a flexible coupling and a shape memory alloy (SMA)-based clamp for micro mechanical systems. It is monolithic and can be directly machined from a shaft. The study performs design optimization and provides manufacturing considerations, including thermo-mechanical training of the SMA ring for the desired Two-Way-Shape-Memory effect (TWSMe). A prototype micro-coupling and a prototype micro-spindle using the proposed coupling are fabricated and tested. The testing results show that the prototype micro-coupling can bear a torque of above 5 N • mm and an axial force of 8.5 N and be fitted with an SMA ring for clamping action at room temperature (15 °C) and unclamping action below-5 °C. At the same time, the prototype micro-coupling can work at a rotational speed of above 200 kr/min with the application to a high-speed precision micro-spindle. Moreover, the radial runout error of the artifact, as a substitute for the micro-tool, is less than 3 μm while that of turbine shaft is above 7 μm. It can be concluded that the micro-coupling successfully accommodates misalignment errors of the prototype micro-spindle. This research proposes a micro-coupling which is featured with an SMA ring, and it is designed to clamp two shafts, and has smooth transmission, simple assembly, compact structure, zero-maintenance and balanced motions.

A Literature Review of Renal Surgical Anatomy and Surgical Strategies for Partial Nephrectomy.

PubMed

Klatte, Tobias; Ficarra, Vincenzo; Gratzke, Christian; Kaouk, Jihad; Kutikov, Alexander; Macchi, Veronica; Mottrie, Alexandre; Porpiglia, Francesco; Porter, James; Rogers, Craig G; Russo, Paul; Thompson, R Houston; Uzzo, Robert G; Wood, Christopher G; Gill, Inderbir S

2015-12-01

A detailed understanding of renal surgical anatomy is necessary to optimize preoperative planning and operative technique and provide a basis for improved outcomes. To evaluate the literature regarding pertinent surgical anatomy of the kidney and related structures, nephrometry scoring systems, and current surgical strategies for partial nephrectomy (PN). A literature review was conducted. Surgical renal anatomy fundamentally impacts PN surgery. The renal artery divides into anterior and posterior divisions, from which approximately five segmental terminal arteries originate. The renal veins are not terminal. Variations in the vascular and lymphatic channels are common; thus, concurrent lymphadenectomy is not routinely indicated during PN for cT1 renal masses in the setting of clinically negative lymph nodes. Renal-protocol contrast-enhanced computed tomography or magnetic resonance imaging is used for standard imaging. Anatomy-based nephrometry scoring systems allow standardized academic reporting of tumor characteristics and predict PN outcomes (complications, remnant function, possibly histology). Anatomy-based novel surgical approaches may reduce ischemic time during PN; these include early unclamping, segmental clamping, tumor-specific clamping (zero ischemia), and unclamped PN. Cancer cure after PN relies on complete resection, which can be achieved by thin margins. Post-PN renal function is impacted by kidney quality, remnant quantity, and ischemia type and duration. Surgical renal anatomy underpins imaging, nephrometry scoring systems, and vascular control techniques that reduce global renal ischemia and may impact post-PN function. A contemporary ideal PN excises the tumor with a thin negative margin, delicately secures the tumor bed to maximize vascularized remnant parenchyma, and minimizes global ischemia to the renal remnant with minimal complications. In this report we review renal surgical anatomy. Renal mass imaging allows detailed delineation of the anatomy and vasculature and permits nephrometry scoring, and thus precise, patient-specific surgical planning. Novel off-clamp techniques have been developed that may lead to improved outcomes. Copyright © 2015 European Association of Urology. Published by Elsevier B.V. All rights reserved.

The simulation on diode-clamped five-level converters common-mode voltage suppression with zero-vector PWM strategy

NASA Astrophysics Data System (ADS)

Zhang, Yonggao; Gao, Yanli; Long, Lizhong

2012-04-01

More and more researchers have great concern on the issue of Common-mode voltage (CMV) in high voltage large power converter. A novel common-mode voltage suppression scheme based on zero-vector PWM strategy (ZVPWM) is present in this paper. Taking a diode-clamped five-level converter as example, the principle of zero vector PWM common-mode voltage (ZCMVPWM) suppression method is studied in detail. ZCMVPWM suppression strategy is including four important parts, which are locating the sector of reference voltage vector, locating the small triangular sub-sector of reference voltage vector, reference vector synthesis, and calculating the operating time of vector. The principles of four important pars are illustrated in detail and the corresponding MATLAB models are established. System simulation and experimental results are provided. It gives some consultation value for the development and research of multi-level converters.

Multi-neuron intracellular recording in vivo via interacting autopatching robots

PubMed Central

Holst, Gregory L; Singer, Annabelle C; Han, Xue; Brown, Emery N

2018-01-01

The activities of groups of neurons in a circuit or brain region are important for neuronal computations that contribute to behaviors and disease states. Traditional extracellular recordings have been powerful and scalable, but much less is known about the intracellular processes that lead to spiking activity. We present a robotic system, the multipatcher, capable of automatically obtaining blind whole-cell patch clamp recordings from multiple neurons simultaneously. The multipatcher significantly extends automated patch clamping, or 'autopatching’, to guide four interacting electrodes in a coordinated fashion, avoiding mechanical coupling in the brain. We demonstrate its performance in the cortex of anesthetized and awake mice. A multipatcher with four electrodes took an average of 10 min to obtain dual or triple recordings in 29% of trials in anesthetized mice, and in 18% of the trials in awake mice, thus illustrating practical yield and throughput to obtain multiple, simultaneous whole-cell recordings in vivo. PMID:29297466

Fabrication and characterization of GaN nanowire doubly clamped resonators

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

Maliakkal, Carina B., E-mail: carina@tifr.res.in; Mathew, John P.; Hatui, Nirupam

2015-09-21

Gallium nitride (GaN) nanowires (NWs) have been intensely researched as building blocks for nanoscale electronic and photonic device applications; however, the mechanical properties of GaN nanostructures have not been explored in detail. The rigidity, thermal stability, and piezoelectric properties of GaN make it an interesting candidate for nano-electromechanical systems. We have fabricated doubly clamped GaN NW electromechanical resonators on sapphire using electron beam lithography and estimated the Young's modulus of GaN from resonance frequency measurements. For wires of triangular cross section with side ∼90 nm, we obtained values for the Young's modulus to be about 218 and 691 GPa, which are ofmore » the same order of magnitude as the values reported for bulk GaN. We also discuss the role of residual strain in the nanowire on the resonant frequency and the orientation dependence of the Young's modulus in wurtzite crystals.« less

Toward a New Gold Standard for Early Safety: Automated Temperature-Controlled hERG Test on the PatchLiner®

PubMed Central

Polonchuk, Liudmila

2012-01-01

The Patchliner® temperature-controlled automated patch clamp system was evaluated for testing drug effects on potassium currents through human ether-à-go-go related gene (hERG) channels expressed in Chinese hamster ovary cells at 35–37°C. IC50 values for a set of reference drugs were compared with those obtained using the conventional voltage clamp technique. The results showed good correlation between the data obtained using automated and conventional electrophysiology. Based on these results, the Patchliner® represents an innovative automated electrophysiology platform for conducting the hERG assay that substantially increases throughput and has the advantage of operating at physiological temperature. It allows fast, accurate, and direct assessment of channel function to identify potential proarrhythmic side effects and sets a new standard in ion channel research for drug safety testing. PMID:22303293

Parallel multipoint recording of aligned and cultured neurons on corresponding Micro Channel Array toward on-chip cell analysis.

PubMed

Tonomura, W; Moriguchi, H; Jimbo, Y; Konishi, S

2008-01-01

This paper describes an advanced Micro Channel Array (MCA) so as to record neuronal network at multiple points simultaneously. Developed MCA is designed for neuronal network analysis which has been studied by co-authors using MEA (Micro Electrode Arrays) system. The MCA employs the principle of the extracellular recording. Presented MCA has the following advantages. First of all, the electrodes integrated around individual micro channels are electrically isolated for parallel multipoint recording. Sucking and clamping of cells through micro channels is expected to improve the cellular selectivity and S/N ratio. In this study, hippocampal neurons were cultured on the developed MCA. As a result, the spontaneous and evoked spike potential could be recorded by sucking and clamping the cells at multiple points. Herein, we describe the successful experimental results together with the design and fabrication of the advanced MCA toward on-chip analysis of neuronal network.

Evidence of a heterogeneous tissue oxygenation: renal ischemia/reperfusion injury in a large animal model

NASA Astrophysics Data System (ADS)

Crane, Nicole J.; Huffman, Scott W.; Alemozaffar, Mehrdad; Gage, Frederick A.; Levin, Ira W.; Elster, Eric A.

2013-03-01

Renal ischemia that occurs intraoperatively during procedures requiring clamping of the renal artery (such as renal procurement for transplantation and partial nephrectomy for renal cancer) is known to have a significant impact on the viability of that kidney. To better understand the dynamics of intraoperative renal ischemia and recovery of renal oxygenation during reperfusion, a visible reflectance imaging system (VRIS) was developed to measure renal oxygenation during renal artery clamping in both cooled and warm porcine kidneys. For all kidneys, normothermic and hypothermic, visible reflectance imaging demonstrated a spatially distinct decrease in the relative oxy-hemoglobin concentration (%HbO2) of the superior pole of the kidney compared to the middle or inferior pole. Mean relative oxy-hemoglobin concentrations decrease more significantly during ischemia for normothermic kidneys compared to hypothermic kidneys. VRIS may be broadly applicable to provide an indicator of organ ischemia during open and laparoscopic procedures.

Thermal stiffening of clamped elastic ribbons

NASA Astrophysics Data System (ADS)

Wan, Duanduan; Nelson, David R.; Bowick, Mark J.

2017-07-01

We use molecular dynamics to study the vibrations of a thermally fluctuating two-dimensional elastic membrane clamped at both ends. We directly extract the eigenmodes from resonant peaks in the frequency domain of the time-dependent height and measure the dependence of the corresponding eigenfrequencies on the microscopic bending rigidity of the membrane, taking care also of the subtle role of thermal contraction in generating a tension when the projected area is fixed. At finite temperatures we show that the effective (macroscopic) bending rigidity tends to a constant as the bare bending rigidity vanishes, consistent with theoretical arguments that the large-scale bending rigidity of the membrane arises from a strong thermal renormalization of the microscopic bending rigidity. Experimental realizations include covalently bonded two-dimensional atomically thin membranes such as graphene and molybdenum disulfide or soft matter systems such as the spectrin skeleton of red blood cells or diblock copolymers.

Ultraprecision XY stage using a hybrid bolt-clamped Langevin-type ultrasonic linear motor for continuous motion.

PubMed

Lee, Dong-Jin; Lee, Sun-Kyu

2015-01-01

This paper presents a design and control system for an XY stage driven by an ultrasonic linear motor. In this study, a hybrid bolt-clamped Langevin-type ultrasonic linear motor was manufactured and then operated at the resonance frequency of the third longitudinal and the sixth lateral modes. These two modes were matched through the preload adjustment and precisely tuned by the frequency matching method based on the impedance matching method with consideration of the different moving weights. The XY stage was evaluated in terms of position and circular motion. To achieve both fine and stable motion, the controller consisted of a nominal characteristics trajectory following (NCTF) control for continuous motion, dead zone compensation, and a switching controller based on the different NCTFs for the macro- and micro-dynamics regimes. The experimental results showed that the developed stage enables positioning and continuous motion with nanometer-level accuracy.

Peptide Probes Reveal a Hydrophobic Steric Ratchet in the Anthrax Toxin Protective Antigen Translocase.

PubMed

Colby, Jennifer M; Krantz, Bryan A

2015-11-06

Anthrax toxin is a tripartite virulence factor produced by Bacillus anthracis during infection. Under acidic endosomal pH conditions, the toxin's protective antigen (PA) component forms a transmembrane channel in host cells. The PA channel then translocates its two enzyme components, lethal factor and edema factor, into the host cytosol under the proton motive force. Protein translocation under a proton motive force is catalyzed by a series of nonspecific polypeptide binding sites, called clamps. A 10-residue guest/host peptide model system, KKKKKXXSXX, was used to functionally probe polypeptide-clamp interactions within wild-type PA channels. The guest residues were Thr, Ala, Leu, Phe, Tyr, and Trp. In steady-state translocation experiments, the channel blocked most tightly with peptides that had increasing amounts of nonpolar surface area. Cooperative peptide binding was observed in the Trp-containing peptide sequence but not the other tested sequences. Trp substitutions into a flexible, uncharged linker between the lethal factor amino-terminal domain and diphtheria toxin A chain expedited translocation. Therefore, peptide-clamp sites in translocase channels can sense large steric features (like tryptophan) in peptides, and while these steric interactions may make a peptide translocate poorly, in the context of folded domains, they can make the protein translocate more rapidly presumably via a hydrophobic steric ratchet mechanism. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

The DnaA N-terminal domain interacts with Hda to facilitate replicase clamp-mediated inactivation of DnaA.

PubMed

Su'etsugu, Masayuki; Harada, Yuji; Keyamura, Kenji; Matsunaga, Chika; Kasho, Kazutoshi; Abe, Yoshito; Ueda, Tadashi; Katayama, Tsutomu

2013-12-01

DnaA activity for replication initiation of the Escherichia coli chromosome is negatively regulated by feedback from the DNA-loaded form of the replicase clamp. In this process, called RIDA (regulatory inactivation of DnaA), ATP-bound DnaA transiently assembles into a complex consisting of Hda and the DNA-clamp, which promotes inter-AAA+ domain association between Hda and DnaA and stimulates hydrolysis of DnaA-bound ATP, producing inactive ADP-DnaA. Using a truncated DnaA mutant, we previously demonstrated that the DnaA N-terminal domain is involved in RIDA. However, the precise role of the N-terminal domain in RIDA has remained largely unclear. Here, we used an in vitro reconstituted system to demonstrate that the Asn-44 residue in the N-terminal domain of DnaA is crucial for RIDA but not for replication initiation. Moreover, an assay termed PDAX (pull-down after cross-linking) revealed an unstable interaction between a DnaA-N44A mutant and Hda. In vivo, this mutant exhibited an increase in the cellular level of ATP-bound DnaA. These results establish a model in which interaction between DnaA Asn-44 and Hda stabilizes the association between the AAA+ domains of DnaA and Hda to facilitate DnaA-ATP hydrolysis during RIDA. © 2013 Society for Applied Microbiology and John Wiley & Sons Ltd.

Cooling/grounding mount for hybrid circuits

NASA Technical Reports Server (NTRS)

Bagstad, B.; Estrada, R.; Mandel, H.

1981-01-01

Extremely short input and output connections, adequate grounding, and efficient heat removal for hybrid integrated circuits are possible with mounting. Rectangular clamp holds hybrid on printed-circuit board, in contact with heat-conductive ground plate. Clamp is attached to ground plane by bolts.

Enhanced optical gain clamping for upstream packet based traffic on hybrid WDM/TDM-PON using fiber Bragg grating

NASA Astrophysics Data System (ADS)

Neto, B.; Klingler, A.; Reis, C.; Dionísio, R. P.; Nogueira, R. N.; Teixeira, A. L. J.; André, P. S.

2011-03-01

In this paper, we propose a method to mitigate the temporal power transients arising from Erbium doped fiber amplifiers (EDFAs) on packeted/bursty scenario. The technique, applicable on hybrid WDM/TDM-PON for extended reach, is based on a low power clamping provided by a distributed feedback (DFB) laser and a fiber Bragg grating (FBG). An improvement in the data signal Q factor was achieved keeping the clamping control signal with a low power, accompanied by a maximum reduction in the gain excursion of 1.12 dB.

Emission control apparatus for internal combustion engines with a controllably disabled clamping circuit

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

Asano, M.

1979-08-28

The invention discloses an emission control apparatus for internal combustion engine includes an exhaust composition sensor to sense the mixture ratio, a circuit for clamping the mixture ratio to a predetermined constant value to prevent the mixture from becoming too rich or too lean when a failure should occur in the control loop, for example, in the exhaust composition sensor failure and a circuit for interrupting the clamping circuit when the engine operating condition is such that the sensor is caused to produce low voltage signals although the sensor is functioning properly.

Natural Vibration Analysis of Clamped Rectangular Orthotropic Plates

NASA Astrophysics Data System (ADS)

dalaei, m.; kerr, a. d.

The natural vibrations of clamped rectangular orthotropic plates are analyzed using the extended Kantorovich method. The developed iterative scheme converges very rapidly to the final result. The obtained natural frequencies are evaluated for a square plate made of Kevlar 49 Epoxy and the obtained results are compared with those published by Kanazawa and Kawai, and by Leissa. The agreement was found to be very close. As there are no exact analytical solutions for clamped rectangular plates, the generated closed form expression for the natural modes, and the corresponding natural frequencies, are very suitable for use in engineering analyses.

Anatomic partial nephrectomy: technique evolution.

PubMed

Azhar, Raed A; Metcalfe, Charles; Gill, Inderbir S

2015-03-01

Partial nephrectomy provides equivalent long-term oncologic and superior functional outcomes as radical nephrectomy for T1a renal masses. Herein, we review the various vascular clamping techniques employed during minimally invasive partial nephrectomy, describe the evolution of our partial nephrectomy technique and provide an update on contemporary thinking about the impact of ischemia on renal function. Recently, partial nephrectomy surgical technique has shifted away from main artery clamping and towards minimizing/eliminating global renal ischemia during partial nephrectomy. Supported by high-fidelity three-dimensional imaging, novel anatomic-based partial nephrectomy techniques have recently been developed, wherein partial nephrectomy can now be performed with segmental, minimal or zero global ischemia to the renal remnant. Sequential innovations have included early unclamping, segmental clamping, super-selective clamping and now culminating in anatomic zero-ischemia surgery. By eliminating 'under-the-gun' time pressure of ischemia for the surgeon, these techniques allow an unhurried, tightly contoured tumour excision with point-specific sutured haemostasis. Recent data indicate that zero-ischemia partial nephrectomy may provide better functional outcomes by minimizing/eliminating global ischemia and preserving greater vascularized kidney volume. Contemporary partial nephrectomy includes a spectrum of surgical techniques ranging from conventional-clamped to novel zero-ischemia approaches. Technique selection should be tailored to each individual case on the basis of tumour characteristics, surgical feasibility, surgeon experience, patient demographics and baseline renal function.

QPatch: the past, present and future of automated patch clamp.

PubMed

Mathes, Chris

2006-04-01

The QPatch 16 significantly increases throughput for gigaseal patch clamp experiments, making direct measurements in ion channel drug discovery and safety testing feasible. Released to the market in the Autumn of 2004 by Sophion Bioscience, the QPatch originated from work done at NeuroSearch (Denmark) in the early days of automated patch clamp. Today, the QPatch provides many unique features. For example, only the QPatch includes an automated cell preparation station making several hours of unattended operation possible. The 16-channel electrode array, called the QPlate, includes glass-coated microfluidic channels for less compound absorption and, hence, more accurate IC(50) values. The microfluidic pathways also allow for very small amounts of compound used for each experiment ( approximately 5 microl per addition). Only the QPatch has four independent pipetting heads for more efficient liquid handling (especially for ligand-gated ion channel experiments). Patch clamp recordings with the QPatch match the high quality of conventional patch clamp and in some cases the results are even better. For example, only the QPatch includes 100% series resistance compensation for the elimination of false positives due to voltage errors. Finally, the modular QPatch 16 was designed with more channels in mind. The upgrade pathway to 48-channels (the QPatch HT) will be discussed.

Plastic Scintillator Based Detector for Observations of Terrestrial Gamma-ray Flashes.

NASA Astrophysics Data System (ADS)

Barghi, M. R., Sr.; Delaney, N.; Forouzani, A.; Wells, E.; Parab, A.; Smith, D.; Martinez, F.; Bowers, G. S.; Sample, J.

2017-12-01

We present an overview of the concept and design of the Light and Fast TGF Recorder (LAFTR), a balloon borne gamma-ray detector designed to observe Terrestrial Gamma-Ray Flashes (TGFs). Terrestrial Gamma-Ray Flashes (TGFs) are extremely bright, sub-millisecond bursts of gamma-rays observed to originate inside thunderclouds coincident with lightning. LAFTR is joint institutional project built by undergraduates at the University of California Santa Cruz and Montana State University. It consists of a detector system fed into analog front-end electronics and digital processing. The presentation focuses specifically on the UCSC components, which consists of the detector system and analog front-end electronics. Because of the extremely high count rates observed during TGFs, speed is essential for both the detector and electronics of the instrument. The detector employs a fast plastic scintillator (BC-408) read out by a SensL Silicon Photomultiplier (SiPM). BC-408 is chosen for its speed ( 4 ns decay time) and low cost and availability. Furthermore, GEANT3 simulations confirm the scintillator is sensitive to 500 counts at 7 km horizontal distance from the TGF source (for a 13 km source altitude and 26 km balloon altitude) and to 5 counts out to 20 km. The signal from the SiPM has a long exponential decay tail and is sent to a custom shaping circuit board that amplifies and shapes the signal into a semi-Gaussian pulse with a 40 ns FWHM. The signal is then input to a 6-channel discriminator board that clamps the signal and outputs a Low Voltage Differential Signal (LVDS) for processing by the digital electronics.

Assessment of insulin resistance in lean women with polycystic ovary syndrome.

PubMed

Morciano, Andrea; Romani, Federica; Sagnella, Francesca; Scarinci, Elisa; Palla, Carola; Moro, Francesca; Tropea, Anna; Policola, Caterina; Della Casa, Silvia; Guido, Maurizio; Lanzone, Antonio; Apa, Rosanna

2014-07-01

To develop and validate a specific simple measure of insulin sensitivity using oral glucose tolerance test (OGTT) values for lean polycystic ovary syndrome (PCOS) women. Retrospective study. Gynecologic Outpatient Clinic of University Hospital, affiliated with Unit of Gynecologic Endocrinology. Totals of 201 lean and 198 overweight/obese (ov-ob) nondiabetic PCOS patients were retrospectively selected. None. All patients underwent OGTT, euglycemic-hyperinsulinemic clamp, and androgenic and biochemical assays. The predictive performance of each insulin resistance (IR) index was analyzed with the use of receiver operating characteristic (ROC) curves. Higher correlation coefficients with clamp studies were obtained with the Belfiore Area (RS=0.579) and the homeostasis-model assessment (HOMA)-M120 (RS=-0.576) in lean PCOS patients and with the Sib (RS=0.697) in ov-ob PCOS patients. The best predictive index of IR in lean PCOS was a HOMA-M120 value of ≥12.8 or more (area under the ROC curve [AUC] 92.4%). In the ov-ob PCOS population, the best predictive performance was obtained by a Sib of ≤10.2 or less (AUC 85.7%). IR should be assessed in all PCOS women, both lean and ov-ob subjects. The HOMA-M120 resulted as a very simple tool, validated specifically for the lean PCOS woman whose cardiometabolic impairment is more frequently misunderstood. Copyright © 2014 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

High voltage bus and auxiliary heater control system for an electric or hybrid vehicle

DOEpatents

Murty, Balarama Vempaty

2000-01-01

A control system for an electric or hybrid electric vehicle includes a vehicle system controller and a control circuit having an electric immersion heater. The heater is electrically connected to the vehicle's high voltage bus and is thermally coupled to a coolant loop containing a heater core for the vehicle's climate control system. The system controller responds to cabin heat requests from the climate control system by generating a pulse width modulated signal that is used by the control circuit to operate the heater at a duty cycle appropriate for the amount of cabin heating requested. The control system also uses the heater to dissipate excess energy produced by an auxiliary power unit and to provide electric braking when regenerative braking is not desirable and manual braking is not necessary. The control system further utilizes the heater to provide a safe discharge of a bank of energy storage capacitors following disconnection of the battery or one of the high voltage connectors used to transmit high voltage operating power to the various vehicle systems. The control circuit includes a high voltage clamping circuit that monitors the voltage on the bus and operates the heater to clamp down the bus voltage when it exceeds a pre-selected maximum voltage. The control system can also be used to phase in operation of the heater when the bus voltage exceeds a lower threshold voltage and can be used to phase out the auxiliary power unit charging and regenerative braking when the battery becomes fully charged.

External pressure measurement system

NASA Astrophysics Data System (ADS)

Chandler, Jon K.; Fowler, Don P.

Hydraulic systems comprise an important part of jet aircraft and their pressure needs must be checked constantly. Tests of the prototype external pressure measurement system show that it is possible to accurately convert the small expansion of tubing with pressure into a direct pressure reading without inserting a pressure gage into the piping system. The tool described in the paper is a clamp-on displacement transducer that can read pressure directly in PSI from 0 to 5000. Some limitations concerning temperature and accuracy should be remedied by additional design work. The system promises to streamline troubleshooting of all types of piping systems.

Change in hexose distribution volume and fractional utilization of ( sup 18 F)-2-deoxy-2-fluoro-D-glucose in brain during acute hypoglycemia in humans

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

Shapiro, E.T.; Cooper, M.; Chen, C.T.

1990-02-01

We used positron emission tomography (PET) to study the effects of mild hypoglycemia on cerebral glucose uptake and metabolism. Nine healthy men were studied under basal saline-infusion conditions, and during euglycemic and hypoglycemic clamp studies. Insulin was infused at the same rate (1 mU.kg-1.min-1) in both clamp studies. In euglycemic clamp studies, glucose was infused at a rate sufficient to maintain the basal plasma glucose concentration, whereas in hypoglycemic clamp studies, the glucose infusion rate was reduced to maintain the plasma glucose at 3.1 mM. Each study lasted 3 h and included a 30-min baseline period and a subsequent 150-minmore » period in which insulin or glucose was administered. Blood samples for measurement of insulin, glucose, cortisol, growth hormone, and glucagon were obtained at 20- to 30-min intervals. A bolus injection of 5-10 mCi (18F)-2-deoxy-2-fluoro-D-glucose (2-DFG) was administered 120 min after initiation of the study, and plasma radioactivity and dynamic PET scans were obtained at frequent intervals for the remaining 40-60 min of the study. Cerebral regions of interest were defined, and concentrations of radioactivity were calculated and used in the three-compartment model of 2-DFG distribution described by Sokoloff. Glucose levels were similar during saline-infusion (4.9 +/- 0.1 mM) and euglycemic clamp (4.8 +/- 0.1 mM) studies, whereas the desired degree of mild hypoglycemia was achieved during the hypoglycemic clamp study (3.1 +/- 0.1 mM, P less than 0.05). The insulin level during saline infusion was 41 +/- 7 pM.« less

Pharmacology of the glucagon-like peptide-1 analog exenatide extended-release in healthy cats.

PubMed

Rudinsky, A J; Adin, C A; Borin-Crivellenti, S; Rajala-Schultz, P; Hall, M J; Gilor, C

2015-04-01

Exenatide extended-release (ER) is a microencapsulated formulation of the glucagon-like peptide 1-receptor agonist exenatide. It has a protracted pharmacokinetic profile that allows a once-weekly injection with comparable efficacy to insulin with an improved safety profile in type II diabetic people. Here, we studied the pharmacology of exenatide ER in 6 healthy cats. A single subcutaneous injection of exenatide ER (0.13 mg/kg) was administered on day 0. Exenatide concentrations were measured for 12 wk. A hyperglycemic clamp (target = 225 mg/dL) was performed on days -7 (clamp I) and 21 (clamp II) with measurements of insulin and glucagon concentrations. Glucose tolerance was defined as the amount of glucose required to maintain hyperglycemia during the clamp. Continuous glucose monitoring was performed on weeks 0, 2, and 6 after injection. Plasma concentrations of exenatide peaked at 1 h and 4 wk after injection. Comparing clamp I with clamp II, fasting blood glucose decreased (mean ± standard deviation = -11 ± 8 mg/dL, P = 0.02), glucose tolerance improved (median [range] +33% [4%-138%], P = 0.04), insulin concentrations increased (+36.5% [-9.9% to 274.1%], P = 0.02), and glucagon concentrations decreased (-4.7% [0%-12.1%], P = 0.005). Compared with preinjection values on continuous glucose monitoring, glucose concentrations decreased and the frequency of readings <50 mg/dL increased at 2 and 6 wk after injection of exenatide ER. This did not correspond to clinical hypoglycemia. No other side effects were observed throughout the study. Exenatide ER was safe and effective in improving glucose tolerance 3 wk after a single injection. Further evaluation is needed to determine its safety, efficacy, and duration of action in diabetic cats. Copyright © 2015 Elsevier Inc. All rights reserved.

Rediscovering sperm ion channels with the patch-clamp technique

PubMed Central

Kirichok, Yuriy; Lishko, Polina V.

2011-01-01

Upon ejaculation, mammalian spermatozoa have to undergo a sequence of physiological transformations within the female reproductive tract that will allow them to reach and fertilize the egg. These include initiation of motility, hyperactivation of motility and perhaps chemotaxis toward the egg, and culminate in the acrosome reaction that permits sperm to penetrate the protective vestments of the egg. These physiological responses are triggered through the activation of sperm ion channels that cause elevations of sperm intracellular pH and Ca2+ in response to certain cues within the female reproductive tract. Despite their key role in sperm physiology and their absolute requirement for the process of fertilization, sperm ion channels remain poorly understood due to the extreme difficulty in application of the patch-clamp technique to spermatozoa. This review covers the topic of sperm ion channels in the following order: first, we discuss how the intracellular Ca2+ and pH signaling mediated by sperm ion channels controls sperm behavior during the process of fertilization. Then, we briefly cover the history of the methodology to study sperm ion channels, which culminated in the recent development of a reproducible whole-cell patch-clamp technique for mouse and human cells. We further discuss the main approaches used to patch-clamp mature mouse and human spermatozoa. Finally, we focus on the newly discovered sperm ion channels CatSper, KSper (Slo3) and HSper (Hv1), identified by the sperm patch-clamp technique. We conclude that the patch-clamp technique has markedly improved and shifted our understanding of the sperm ion channels, in addition to revealing significant species-specific differences in these channels. This method is critical for identification of the molecular mechanisms that control sperm behavior within the female reproductive tract and make fertilization possible. PMID:21642646

Scanning electron microscope/energy dispersive x ray analysis of impact residues on LDEF tray clamps

NASA Technical Reports Server (NTRS)

Bernhard, Ronald P.; Durin, Christian; Zolensky, Michael E.

1992-01-01

To better understand the nature of particulates in low-Earth orbit (LEO), and their effects on spacecraft hardware, we are analyzing residues found in impacts on the Long Duration Exposure Facility (LDEF) tray clamps. LDEF experiment trays were held in place by 6 to 8 chromic-anodized aluminum (6061-T6) clamps that were fastened to the spacecraft frame using three stainless steel hex bolts. Each clamp exposed an area of approximately 58 sq cm (4.8 cm x 12.7 cm x .45 cm, minus the bolt coverage). Some 337 out of 774 LDEF tray clamps were archived at JSC and are available through the Meteoroid & Debris Special Investigation Group (M&D SIG). Optical scanning of clamps, starting with Bay/Row A01 and working toward H25, is being conducted at JSC to locate and document impacts as small as 40 microns. These impacts are then inspected by Scanning Electron Microscopy/Energy Dispersive X-ray Analysis (SEM/EDXA) to select those features which contain appreciable impact residue material. Based upon the composition of projectile remnants, and using criteria developed at JSC, we have made a preliminary discrimination between micrometeoroid and space debris residue-containing impact features. Presently, 13 impacts containing significant amounts of unmelted and semi-melted micrometeoritic residues were forwarded to Centre National d'Etudes Spatiales (CNES) in France. At the CNES facilities, the upgraded impacts were analyzed using a JEOL T330A SEM equipped with a NORAN Instruments, Voyager X-ray Analyzer. All residues were quantitatively characterized by composition (including oxygen and carbon) to help understand interplanetary dust as possibly being derived from comets and asteroids.

Estimating the Cost of Early Infant Male Circumcision in Zimbabwe: Results From a Randomized Noninferiority Trial of AccuCirc Device Versus Mogen Clamp

PubMed Central

Mavhu, Webster; Hatzold, Karin; Biddle, Andrea K.; Madidi, Ngonidzashe; Ncube, Getrude; Mugurungi, Owen; Ticklay, Ismail; Cowan, Frances M.; Thirumurthy, Harsha

2015-01-01

Background: Safe and cost-effective programs for implementing early infant male circumcision (EIMC) in Africa need to be piloted. We present results on a relative cost analysis within a randomized noninferiority trial of EIMC comparing the AccuCirc device with Mogen clamp in Zimbabwe. Methods: Between January and June 2013, male infants who met inclusion criteria were randomized to EIMC through either AccuCirc or Mogen clamp conducted by a doctor, using a 2:1 allocation ratio. We evaluated the overall unit cost plus the key cost drivers of EIMC using both AccuCirc and Mogen clamp. Direct costs included consumable and nonconsumable supplies, device, personnel, associated staff training, and environmental costs. Indirect costs comprised capital and support personnel costs. In 1-way sensitivity analyses, we assessed potential changes in unit costs due to variations in main parameters, one at a time, holding all other values constant. Results: The unit costs of EIMC using AccuCirc and Mogen clamp were $49.53 and $55.93, respectively. Key cost drivers were consumable supplies, capacity utilization, personnel costs, and device price. Unit prices are likely to be lowest at full capacity utilization and increase as capacity utilization decreases. Unit prices also fall with lower personnel salaries and increase with higher device prices. Conclusions: EIMC has a lower unit cost when using AccuCirc compared with Mogen clamp. To minimize unit costs, countries planning to scale-up EIMC using AccuCirc need to control costs of consumables and personnel. There is also need to negotiate a reasonable device price and maximize capacity utilization. PMID:26017658

A retrospective analysis of laparoscopic partial nephrectomy with segmental renal artery clamping and factors that predict postoperative renal function.

PubMed

Li, Pu; Qin, Chao; Cao, Qiang; Li, Jie; Lv, Qiang; Meng, Xiaoxin; Ju, Xiaobing; Tang, Lijun; Shao, Pengfei

2016-10-01

To evaluate the feasibility and efficiency of laparoscopic partial nephrectomy (LPN) with segmental renal artery clamping, and to analyse the factors affecting postoperative renal function. We conducted a retrospective analysis of 466 consecutive patients undergoing LPN using main renal artery clamping (group A, n = 152) or segmental artery clamping (group B, n = 314) between September 2007 and July 2015 in our department. Blood loss, operating time, warm ischaemia time (WIT) and renal function were compared between groups. Univariable and multivariable linear regression analyses were applied to assess the correlations of selected variables with postoperative glomerular filtration rate (GFR) reduction. Volumetric data and estimated GFR of a subset of 60 patients in group B were compared with GFR to evaluate the correlation between these functional variables and preserved renal function after LPN. The novel technique slightly increased operating time, WIT and intra-operative blood loss (P < 0.001), while it provided better postoperative renal function (P < 0.001) compared with the conventional technique. The blocking method and tumour characteristics were independent factors affecting GFR reduction, while WIT was not an independent factor. Correlation analysis showed that estimated GFR presented better correlation with GFR compared with kidney volume (R(2) = 0.794 cf. R(2) = 0.199) in predicting renal function after LPN. LPN with segmental artery clamping minimizes warm ischaemia injury and provides better early postoperative renal function compared with clamping the main renal artery. Kidney volume has a significantly inferior role compared with eGFR in predicting preserved renal function. © 2016 The Authors BJU International © 2016 BJU International Published by John Wiley & Sons Ltd.

Perturbed atrial calcium handling in an ovine model of heart failure: Potential roles for reductions in the L-type calcium current

PubMed Central

Clarke, Jessica D.; Caldwell, Jessica L.; Horn, Margaux A.; Bode, Elizabeth F.; Richards, Mark A.; Hall, Mark C.S.; Graham, Helen K.; Briston, Sarah J.; Greensmith, David J.; Eisner, David A.; Dibb, Katharine M.; Trafford, Andrew W.

2015-01-01

Heart failure (HF) is commonly associated with reduced cardiac output and an increased risk of atrial arrhythmias particularly during β-adrenergic stimulation. The aim of the present study was to determine how HF alters systolic Ca2 + and the response to β-adrenergic (β-AR) stimulation in atrial myocytes. HF was induced in sheep by ventricular tachypacing and changes in intracellular Ca2 + concentration studied in single left atrial myocytes under voltage and current clamp conditions. The following were all reduced in HF atrial myocytes; Ca2 + transient amplitude (by 46% in current clamped and 28% in voltage clamped cells), SR dependent rate of Ca2 + removal (kSR, by 32%), L-type Ca2 + current density (by 36%) and action potential duration (APD90 by 22%). However, in HF SR Ca2 + content was increased (by 19%) when measured under voltage-clamp stimulation. Inhibiting the L-type Ca2 + current (ICa-L) in control cells reproduced both the decrease in Ca2 + transient amplitude and increase of SR Ca2 + content observed in voltage-clamped HF cells. During β-AR stimulation Ca2 + transient amplitude was the same in control and HF cells. However, ICa-L remained less in HF than control cells whilst SR Ca2 + content was highest in HF cells during β-AR stimulation. The decrease in ICa-L that occurs in HF atrial myocytes appears to underpin the decreased Ca2 + transient amplitude and increased SR Ca2 + content observed in voltage-clamped cells. PMID:25463272

Midwives in India: a delayed cord clamping intervention using simulation.

PubMed

Faucher, M A; Riley, C; Prater, L; Reddy, M P

2016-09-01

Iron deficiency is a prevalent health problem in India affecting women and newborns. Delayed umbilical cord clamping at birth is a safe and effective means for increasing serum iron levels in newborns up to 6 months of age. The study aim was to increase the utilization of delayed cord clamping in a group of midwives working in Hyderabad, India. A single group pre- and post-test design was used to evaluate knowledge, beliefs and practice before and after a delayed cord clamping intervention including follow-up at 10 months after the original intervention. The intervention included lectures and simulation. Results show significant increases in knowledge and positive beliefs about the practice of delayed cord clamping. Simulation was effective for eliciting important feedback related to learning. Results represent a small group of midwives working with a non-profit foundation in Southern India. Language discordancy and cultural norms in this group of midwives may have influenced results. Knowledge, beliefs and practice related to delayed cord clamping were all significantly improved after the intervention. The Knowledge to Action framework using simulation is an effective cross-cultural method for implementing education about evidence-based practice. Midwives are invested in learning practices that promote public health. Changing institutional policy may have limitations without first considering normative practice. Using simulation combined with institutional health policy appears to result in significant uptake of practice change. Qualitative studies exploring the interconnections between cultural norms and decision making may be informative about promoting practice change particularly in this setting. Upscaling midwifery has been recommended to improve maternal and child health in India. © 2016 International Council of Nurses.

Apparatus for unloading nuclear fuel pellets from a sintering boat

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

Bucher, G.D.; Raymond, T.E.

1987-02-10

An apparatus is described for unloading nuclear fuel pellets from a loaded sintering boat having an open top, comprising: (a) means for receiving the boat in an upright position with the pellets contained therein, the boat receiving means including a platform for supporting the loaded boat in the upright position, the boat supporting platform having first and second portions; (b) means for clamping the boat including a pair of plates disposed at lateral sides of the boat and being movable in a first direction relative to one another for applying clamping forces to the boat on the platform and inmore » a second direction relative to one another for releasing the clamping forces from the boat. The pair of plates have inner surfaces facing toward one another, the first and second platform portions of the boat supporting platform being mounted to the plates on the respective facing surfaces thereof and disposed in a common plane. One of the plates and one of the platform portions mounted thereto are disposed in a stationary position and the other of the plates and the other of the platform portions mounted thereto are movable relative thereto in the first and second directions for applying and releasing clamping forces to and from the boat while the boat is supported in the upright position by the platform portions; (c) means for transferring the clamped boat from the upright position to an inverted position and then back to the upright position; and (d) means of receiving the pellets from the clamped boat as the boat is being transferred from the upright position to the inverted position.« less

Opto-current-clamp actuation of cortical neurons using a strategically designed channelrhodopsin.

PubMed

Wen, Lei; Wang, Hongxia; Tanimoto, Saki; Egawa, Ryo; Matsuzaka, Yoshiya; Mushiake, Hajime; Ishizuka, Toru; Yawo, Hiromu

2010-09-23

Optogenetic manipulation of a neuronal network enables one to reveal how high-order functions emerge in the central nervous system. One of the Chlamydomonas rhodopsins, channelrhodopsin-1 (ChR1), has several advantages over channelrhodopsin-2 (ChR2) in terms of the photocurrent kinetics. Improved temporal resolution would be expected by the optogenetics using the ChR1 variants with enhanced photocurrents. The photocurrent retardation of ChR1 was overcome by exchanging the sixth helix domain with its counterpart in ChR2 producing Channelrhodopsin-green receiver (ChRGR) with further reform of the molecule. When the ChRGR photocurrent was measured from the expressing HEK293 cells under whole-cell patch clamp, it was preferentially activated by green light and has fast kinetics with minimal desensitization. With its kinetic advantages the use of ChRGR would enable one to inject a current into a neuron by the time course as predicted by the intensity of the shedding light (opto-current clamp). The ChRGR was also expressed in the motor cortical neurons of a mouse using Sindbis pseudovirion vectors. When an oscillatory LED light signal was applied sweeping through frequencies, it robustly evoked action potentials synchronized to the oscillatory light at 5-10 Hz in layer 5 pyramidal cells in the cortical slice. The ChRGR-expressing neurons were also driven in vivo with monitoring local field potentials (LFPs) and the time-frequency energy distribution of the light-evoked response was investigated using wavelet analysis. The oscillatory light enhanced both the in-phase and out-phase responses of LFP at the preferential frequencies of 5-10 Hz. The spread of activity was evidenced by the fact that there were many c-Fos-immunoreactive neurons that were negative for ChRGR in a region of the motor cortex. The opto-current-clamp study suggests that the depolarization of a small number of neurons wakes up the motor cortical network over some critical point to the activated state.

Extending the upper temperature range of gas chromatography with all-silicon microchip columns using a heater/clamp assembly.

PubMed

Ghosh, Abhijit; Johnson, Jacob E; Nuss, Johnathan G; Stark, Brittany A; Hawkins, Aaron R; Tolley, Luke T; Iverson, Brian D; Tolley, H Dennis; Lee, Milton L

2017-09-29

Miniaturization of gas chromatography (GC) instrumentation is of interest because it addresses current and future issues relating to compactness, portability and field application. While incremental advancements continue to be reported in GC with columns fabricated in microchips (referred to in this paper as "microchip columns"), the current performance is far from acceptable. This lower performance compared to conventional GC is due to factors such as pooling of the stationary phase in corners of non-cylindrical channels, adsorption of sensitive compounds on incompletely deactivated surfaces, shorter column lengths and less than optimum interfacing to injector and detector. In this work, a GC system utilizing microchip columns was developed that solves the latter challenge, i.e., microchip interfacing to injector and detector. A microchip compression clamp was constructed to heat the microchip (i.e., primary heater), and seal the injector and detector fused silica interface tubing to the inlet and outlet ports of the microchip channels with minimum extra-column dead volume. This clamp allowed occasional operation up to 375°C and routine operation up to 300°C. The compression clamp was constructed of a low expansion alloy, Kovar™, to minimize leaking due to thermal expansion mismatch at the interface during repeated thermal cycling, and it was tested over several months for more than one hundred injections without forming leaks. A 5.9m long microcolumn with rectangular cross section of 158μm×80μm, which approximately matches a 100μm i.d. cylindrical fused silica column, was fabricated in a silicon wafer using deep reactive ion etching (DRIE) and high temperature fusion bonding; finally, the channel was coated statically with a 1% vinyl, 5% phenyl, 94% methylpolysiloxane stationary phase. High temperature separations of C10-C40 n-alkanes and a commercial diesel sample were demonstrated using the system under both temperature programmed GC (TPGC) and thermal gradient GC (TGGC) conditions. TGGC analysis of a complex essential oil sample was also demonstrated. Addition of a secondary heater and polyimide insulation proved to be helpful in achieving the desired elution temperature without having to raise the primary heater temperature above 300°C for high boiling point compounds. Copyright © 2017 Elsevier B.V. All rights reserved.

An international land-biosphere model benchmarking activity for the IPCC Fifth Assessment Report (AR5)

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

Hoffman, Forrest M; Randerson, James T; Thornton, Peter E

2009-12-01

The need to capture important climate feedbacks in general circulation models (GCMs) has resulted in efforts to include atmospheric chemistry and land and ocean biogeochemistry into the next generation of production climate models, called Earth System Models (ESMs). While many terrestrial and ocean carbon models have been coupled to GCMs, recent work has shown that such models can yield a wide range of results (Friedlingstein et al., 2006). This work suggests that a more rigorous set of global offline and partially coupled experiments, along with detailed analyses of processes and comparisons with measurements, are needed. The Carbon-Land Model Intercomparison Projectmore » (C-LAMP) was designed to meet this need by providing a simulation protocol and model performance metrics based upon comparisons against best-available satellite- and ground-based measurements (Hoffman et al., 2007). Recently, a similar effort in Europe, called the International Land Model Benchmark (ILAMB) Project, was begun to assess the performance of European land surface models. These two projects will now serve as prototypes for a proposed international land-biosphere model benchmarking activity for those models participating in the IPCC Fifth Assessment Report (AR5). Initially used for model validation for terrestrial biogeochemistry models in the NCAR Community Land Model (CLM), C-LAMP incorporates a simulation protocol for both offline and partially coupled simulations using a prescribed historical trajectory of atmospheric CO2 concentrations. Models are confronted with data through comparisons against AmeriFlux site measurements, MODIS satellite observations, NOAA Globalview flask records, TRANSCOM inversions, and Free Air CO2 Enrichment (FACE) site measurements. Both sets of experiments have been performed using two different terrestrial biogeochemistry modules coupled to the CLM version 3 in the Community Climate System Model version 3 (CCSM3): the CASA model of Fung, et al., and the carbon-nitrogen (CN) model of Thornton. Comparisons of the CLM3 offline results against observational datasets have been performed and are described in Randerson et al. (2009). CLM version 4 has been evaluated using C-LAMP, showing improvement in many of the metrics. Efforts are now underway to initiate a Nitrogen-Land Model Intercomparison Project (N-LAMP) to better constrain the effects of the nitrogen cycle in biosphere models. Presented will be new results from C-LAMP for CLM4, initial N-LAMP developments, and the proposed land-biosphere model benchmarking activity.« less

Laser-Raman Measurements in the Muzzle Blast Region of a 20-mm Cannon

DTIC Science & Technology

1980-08-01

Figs. 5 and 6, the entire spectrometer system was mounted below the laser syste m on the same two-tiered aluminum table which was clamped to the top... Thermometric Measurements of Propellant Gas Temperatures in Guns." AIAA Journal, Vol. 15, No. 2, February 1977, pp. 222-226. 4. Schmidt, E. M., Fansler

Clamp and Gas Nozzle for TIG Welding

NASA Technical Reports Server (NTRS)

Gue, G. B.; Goller, H. L.

1982-01-01

Tool that combines clamp with gas nozzle is aid to tungsten/inert-gas (TIG) welding in hard-to-reach spots. Tool holds work to be welded while directing a stream of argon gas at weld joint, providing an oxygen-free environment for tungsten-arc welding.

Carbon nanotube-clamped metal atomic chain

PubMed Central

Tang, Dai-Ming; Yin, Li-Chang; Li, Feng; Liu, Chang; Yu, Wan-Jing; Hou, Peng-Xiang; Wu, Bo; Lee, Young-Hee; Ma, Xiu-Liang; Cheng, Hui-Ming

2010-01-01

Metal atomic chain (MAC) is an ultimate one-dimensional structure with unique physical properties, such as quantized conductance, colossal magnetic anisotropy, and quantized magnetoresistance. Therefore, MACs show great potential as possible components of nanoscale electronic and spintronic devices. However, MACs are usually suspended between two macroscale metallic electrodes; hence obvious technical barriers exist in the interconnection and integration of MACs. Here we report a carbon nanotube (CNT)-clamped MAC, where CNTs play the roles of both nanoconnector and electrodes. This nanostructure is prepared by in situ machining a metal-filled CNT, including peeling off carbon shells by spatially and elementally selective electron beam irradiation and further elongating the exposed metal nanorod. The microstructure and formation process of this CNT-clamped MAC are explored by both transmission electron microscopy observations and theoretical simulations. First-principles calculations indicate that strong covalent bonds are formed between the CNT and MAC. The electrical transport property of the CNT-clamped MAC was experimentally measured, and quantized conductance was observed. PMID:20427743

A novel way to go whole-cell in patch-clamp experiments.

PubMed

Inayat, Samsoon; Zhao, Yan; Cantrell, Donal R; Dikin, Dmitryi; Pinto, Lawrence H; Troy, John B

2010-11-01

With a conventional patch-clamp electrode, an Ag/AgCl wire sits stationary inside the pipette. To move from the gigaseal cell-attached configuration to whole-cell recording, suction is applied inside the pipette. We have designed and developed a novel Pushpen patch-clamp electrode, in which a W wire insulated and wound with Ag/AgCl wire can move linearly inside the pipette. The W wire has a conical tip, which can protrude from the pipette tip like a push pen, a procedure we call the Pushpen Operation. We use the Pushpen operation to impale the cell membrane in cell-attached configuration to go whole-cell without disruption of the gigaseal. We successfully recorded whole-cell currents from chinese hamster ovarian cells expressing influenza A virus protein A/M2, after obtaining whole-cell configuration with the Pushpen operation. This novel method of achieving whole-cell configuration may have a higher success rate than is the case with the conventional patch clamp technique.

A monolithic patch-clamping amplifier with capacitive feedback.

PubMed

Prakash, J; Paulos, J J; Jensen, D N

1989-03-01

Patch-clamping is an established method for directly measuring ionic transport through cellular membranes with sufficient resolution to observe open/close transitions of individual channel molecules. This paper describes an alternative technique for patch-clamping which uses a capacitor as the transimpedance element. This approach eliminates bandwidth and saturation limitations experienced with resistive patch-clamping amplifiers. A complete monolithic design featuring an on-chip operational amplifier, a capacitor array with gain-ranging from 30 pF down to 0.03 pF, and reset and gain ranging switches has been fabricated using 5 microns CMOS technology. It is shown that the voltage noise of the CMOS operational amplifier limits the overall noise performance, but that performance competitive with conventional instruments can be achieved over a 10 kHz bandwidth, at least for small input capacitances (less than or equal to 5 pF). Results are presented along with an analysis and comparison of noise performance using both resistive and capacitive elements.

Analytical and experimental investigation on transmission loss of clamped double panels: implication of boundary effects.

PubMed

Xin, F X; Lu, T J

2009-03-01

The air-borne sound insulation performance of a rectangular double-panel partition clamp mounted on an infinite acoustic rigid baffle is investigated both analytically and experimentally and compared with that of a simply supported one. With the clamped (or simply supported) boundary accounted for by using the method of modal function, a double series solution for the sound transmission loss (STL) of the structure is obtained by employing the weighted residual (Galerkin) method. Experimental measurements with Al double-panel partitions having air cavity are subsequently carried out to validate the theoretical model for both types of the boundary condition, and good overall agreement is achieved. A consistency check of the two different models (based separately on clamped modal function and simply supported modal function) is performed by extending the panel dimensions to infinite where no boundaries exist. The significant discrepancies between the two different boundary conditions are demonstrated in terms of the STL versus frequency plots as well as the panel deflection mode shapes.

Sensitive and label-free detection of miRNA-145 by triplex formation.

PubMed

Aviñó, Anna; Huertas, César S; Lechuga, Laura M; Eritja, Ramon

2016-01-01

The development of new strategies for detecting microRNAs (miRNAs) has become a crucial step in the diagnostic field. miRNA profiles depend greatly on the sample and the analytical platform employed, leading sometimes to contradictory results. In this work, we study the use of modified parallel tail-clamps to detect a miRNA sequence involved in tumor suppression by triplex formation. Thermal denaturing curves and circular dichroism (CD) measurements have been performed to confirm that parallel clamps carrying 8-aminoguanine form the most stable triplex structures with their target miRNA. The modified tail-clamps have been tested as bioreceptors in a surface plasmon resonance (SPR) biosensor for the detection of miRNA-145. The detection limit was improved 2.4 times demonstrating that a stable triplex structure is formed between target miRNA and 8-aminoguanine tail-clamp bioreceptor. This new approach is an essential step toward the label-free and reliable detection of miRNA signatures for diagnostic purposes.

Single-Centre Experience of Off-Pump Multi-Vessel Coronary Artery Bypass Grafting Using Proximal Suture Device.

PubMed

Ohira, Suguru; Doi, Kiyoshi; Numata, Satoshi; Yamazaki, Sachiko; Itatani, Keiichi; Kawajiri, Hidetake; Morimoto, Kazuki; Yaku, Hitoshi

2017-10-01

To investigate the results of off-pump coronary artery grafting (OPCAB) with the proximal suture device (PSD) regarding postoperative stroke and graft patency. The PSD was used in 376 patients (32.0%), aorta-no-touch OPCAB was performed in 523 patients (45.2%), on-pump beating coronary artery bypass surgery (CABG) (on-beat group) in 125 patients (10.6%) including 51 conversions (conversion rate: 5.4%), and CABG with aortic clamp use (clamp group) in 152 patients. In the PSD group, Enclose II was used in 267 patients (71.0%). The hospital mortality rate was 1.95%. There was no early stroke in the OPCAB group, whereas the early-stroke rate was 0.8% in the on-beat group and 2.6% in the clamp group. The incidences of stroke at one month were: PSD group, 1.6%; no-touch group, 1.1%; on-beat group, 1.6%; and clamp group, 4.6% (p=0.014). The rates of complete revascularisation were higher in the PSD and clamp groups (94.7 and 94.0%, respectively) compared with the no-touch and on-beat groups (81.5 and 84.9%, respectively; p<0.001). The vein graft patency rates were comparable between the PSD and clamp groups. In multiple logistic regression analysis, OPCAB using the PSD did not increase the risk of stroke compared with the no-touch group (adjusted odds ratio [AOR]: 1.40; p=0.594) or on-beat group (AOR: 0.99; p=0.206), but reduced the risk of stroke compared with the clamp group (AOR: 0.19; p=0.005). Off-pump coronary artery grafting using the PSD was a safe and effective procedure. It led to lower incidences of postoperative stroke and excellent rates of graft patency and complete revascularisation compared with conventional CABG. Copyright © 2016 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Published by Elsevier B.V. All rights reserved.

Fibrin Sealant Improves Hemostasis in Peripheral Vascular Surgery: A Randomized Prospective Trial

PubMed Central

Schenk, Worthington G.; Burks, Sandra G.; Gagne, Paul J.; Kagan, Steven A.; Lawson, Jeffrey H.; Spotnitz, William D.

2003-01-01

Objective To evaluate the efficacy and safety of an investigational fibrin sealant (FS) in a randomized prospective, partially blinded, controlled, multicenter trial. Summary Background Data Upper extremity vascular access surgery using polytetrafluorethylene (PTFE) graft placement for dialysis was chosen as a reproducible, clinically relevant model for evaluating the usefulness of FS. The FS consisted of pooled human fibrinogen (60 mg/mL) and thrombin (500 NIH U/mL). Time to hemostasis was measured, and adverse events were monitored. Methods Consenting adult patients (n = 48) undergoing placement of a standard PTFE graft were randomized in a 2:1:1 ratio to the treatment group using FS (ZLB Bioplasma AG, Bern, Switzerland), oxidized regenerated cellulose (Surgicel, Johnson & Johnson, New Brunswick, NJ), or pressure. Patients received heparin (3,000 IU IVP) before placement of vascular clamps. If the treatment was FS, clamps were left in place for 120 seconds after the application of study material to permit polymerization. If treatment was Surgicel, clamps were left in place until the agent had been applied according to manufacturer’s instructions. If the treatment was pressure, clamps were released as soon as the investigator was ready to apply compression. Immediately after release of the last clamp, the arterial and venous suture lines were evaluated for bleeding. The time to hemostasis at both the venous and arterial sites was recorded. Results Significant (P ≤ .005) reduction in time to hemostasis was achieved in the FS group. Thirteen (54.2%) patients randomized to FS experienced immediate hemostasis at both suture lines following clamp removal compared to no patients using Surgicel or pressure. Only one patient (7.1%) in the Surgicel group and no patients in the pressure group experienced hemostasis at 120 seconds from clamp removal, compared to 13 (54.2%) patients for FS. Adverse events were comparable in all groups. There were no seroconversions. Conclusions FS achieved more rapid hemostasis than traditional techniques in this peripheral vascular procedure. FS use appeared to be safe for this procedure. PMID:12796584

Bio-mimicking of Proline-Rich Motif Applied to Carbon Nanotube Reveals Unexpected Subtleties Underlying Nanoparticle Functionalization

NASA Astrophysics Data System (ADS)

Zhang, Yuanzhao; Jimenez-Cruz, Camilo A.; Wang, Jian; Zhou, Bo; Yang, Zaixing; Zhou, Ruhong

2014-11-01

Here, we report computational studies of the SH3 protein domain interacting with various single-walled carbon nanotubes (SWCNT) either bare or functionalized by mimicking the proline-rich motif (PRM) ligand (PPPVPPRR) and compare it to the SH3-PRM complex binding. With prolines or a single arginine attached, the SWCNT gained slightly on specificity when compared with the bare control, whereas with multi-arginine systems the specificity dropped dramatically to our surprise. Although the electrostatic interaction provided by arginines is crucial in the recognition between PRM and SH3 domain, our results suggest that attaching multiple arginines to the SWCNT has a detrimental effect on the binding affinity. Detailed analysis of the MD trajectories found two main factors that modulate the specificity of the binding: the existence of competing acidic patches at the surface of SH3 that leads to ``trapping and clamping'' by the arginines, and the rigidity of the SWCNT introducing entropic penalties in the proper binding. Further investigation revealed that the same ``clamping'' phenomenon exits in the PRM-SH3 system, which has not been reported in previous literature. The competing effects between nanoparticle and its functionalization components revealed by our model system should be of value to current and future nanomedicine designs.

Effects of cooling system parameters on heat transfer in PAFC stack. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Abdul-Aziz, Ali A.

1985-01-01

Analytical and experimental study for the effects of cooling system parameters on the heat transfer and temperature distribution in the electrode plates of a phosphoric acid fuel-cell has been conducted. An experimental set-up that simulates the operating conditions prevailing in a phosphoric-acid fuel-cell stack was designed and constructed. The set-up was then used to measure the overall heat transfer coefficient, the thermal contact resistance, and the electrode temperature distribution for two different cooling plate configurations. Two types of cooling plate configurations, serpentine and straight, were tested. Air, water, and oil were used as coolants. Measurements for the heat transfer coefficient and the thermal contact resistance were made for various flow rates ranging from 16 to 88 Kg/hr, and stack clamping pressure ranging from O to 3448 Kpa. The experimental results for the overall heat transfer coefficient were utilized to derive mathematical relations for the overall heat transfer coefficient as a function of stack clamping pressure and Reynolds number for the three coolants. The empirically derived formulas were incorporated in a previously developed computer program to predict electrodes temperature distribution and the performance of the stack cooling system. The results obtained were then compared with those available in the literature. The comparison showed maximum deviation of +/- 11%.

Stand-Sit Microchip for High-Throughput, Multiplexed Analysis of Single Cancer Cells.

PubMed

Ramirez, Lisa; Herschkowitz, Jason I; Wang, Jun

2016-09-01

Cellular heterogeneity in function and response to therapeutics has been a major challenge in cancer treatment. The complex nature of tumor systems calls for the development of advanced multiplexed single-cell tools that can address the heterogeneity issue. However, to date such tools are only available in a laboratory setting and don't have the portability to meet the needs in point-of-care cancer diagnostics. Towards that application, we have developed a portable single-cell system that is comprised of a microchip and an adjustable clamp, so on-chip operation only needs pipetting and adjusting of clamping force. Up to 10 proteins can be quantitated from each cell with hundreds of single-cell assays performed in parallel from one chip operation. We validated the technology and analyzed the oncogenic signatures of cancer stem cells by quantitating both aldehyde dehydrogenase (ALDH) activities and 5 signaling proteins in single MDA-MB-231 breast cancer cells. The technology has also been used to investigate the PI3K pathway activities of brain cancer cells expressing mutant epidermal growth factor receptor (EGFR) after drug intervention targeting EGFR signaling. Our portable single-cell system will potentially have broad application in the preclinical and clinical settings for cancer diagnosis in the future.

Outside-out "sniffer-patch" clamp technique for in situ measures of neurotransmitter release.

PubMed

Muller-Chrétien, Emilie

2014-01-01

The mechanism underlying neurotransmitter release is a critical research domain for the understanding of neuronal network function; however, few techniques are available for the direct detection and measurement of neurotransmitter release. To date, the sniffer-patch clamp technique is mainly used to investigate these mechanisms from individual cultured cells. In this study, we propose to adapt the sniffer-patch clamp technique to in situ detection of neurosecretion. Using outside-out patches from donor cells as specific biosensors plunged in acute cerebral slices, this technique allows for proper detection and quantification of neurotransmitter release at the level of the neuronal network.

30 CFR 18.40 - Cable clamps and grips.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Cable clamps and grips. 18.40 Section 18.40 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS ELECTRIC MOTOR-DRIVEN MINE EQUIPMENT AND ACCESSORIES Construction and Design...

Electric Fuel Pump Condition Monitor System Using Electricalsignature Analysis

DOEpatents

Haynes, Howard D [Knoxville, TN; Cox, Daryl F [Knoxville, TN; Welch, Donald E [Oak Ridge, TN

2005-09-13

A pump diagnostic system and method comprising current sensing probes clamped on electrical motor leads of a pump for sensing only current signals on incoming motor power, a signal processor having a means for buffering and anti-aliasing current signals into a pump motor current signal, and a computer having a means for analyzing, displaying, and reporting motor current signatures from the motor current signal to determine pump health using integrated motor and pump diagnostic parameters.

The hypertriglyceridemic clamp technique. Studies using long-chain and structured triglyceride emulsions in healthy subjects.

PubMed

Nordenström, Jörgen; Thörne, Anders; Aberg, Wiveca; Carneheim, Claes; Olivecrona, Thomas

2006-11-01

In a randomized crossover study, plasma kinetics of 2 different types of fat emulsions were studied in 8 healthy volunteers by using a hypertriglyceridemic clamp technique. The method involves the stabilization of serum triglyceride (TG) concentration during 180 minutes at a predetermined level (4 mmol/L) by adjustment of TG infusion rate by repeated online measurements of serum TG concentration. The fat emulsions under study were a long-chain fatty acid triglyceride (LCT) emulsion (Intralipid 20%, Fresenius Kabi, Sweden) and a structured triglyceride (STG) emulsion (Structolipid 20%, Fresenius Kabi) where medium- and long-chain fatty acids have been interesterified within a TG molecule. The hypertriglyceridemic clamp was found to have acceptable reproducibility when tested in 3 healthy individuals on 2 different occasions, as similar steady-state TG levels were obtained by infusing similar amounts of fat. The average (+/-SEM) TG concentration during the 180-minute clamp was similar for STGs and LCTs (4.0 +/- 0.1 vs 3.9 +/- 0.1 mmol/L; not significant), but the amount of fat that had to be infused was significantly higher during STG than during LCT clamping (0.31 +/- 0.04 vs 0.21 +/- 0.02 g TG per minute; P < .05). Higher serum levels of free fatty acids (1.80 +/- 0.13 vs 0.96 +/- 0.09 mmol/L; P < .05), free glycerol (1.30 +/- 0.07 vs 0.76 +/- 0.08 mmol/L; P < .001), and beta-OH butyrate (1.61 +/- 0.44 vs 1.17 +/- 0.23 mmol/L; not significant) were obtained at the end of the clamp during infusion of STGs compared with LCTs. During infusion of STGs the medium-chain fatty acids octanoic (C:8) and decanoic acid (C:10) constituted approximately half of circulating fatty acids that correspond to the compositional ratio of the emulsion. Plasma lipoprotein lipase (LPL) concentration was higher during STG than during LCT clamping (6.06 +/- 0.62 vs 3.15 +/- 0.40 mU/mL; P < .05), and there was a positive correlation between the mean LPL concentration and the amount of infused TG during the steady-state period (r = 0.58; P < .05). In conclusion, the hypertriglyceridemic clamp method was found to give reproducible results and could be considered for comparison of metabolic clearance properties of different types of fat emulsions. The capacity of healthy subjects to eliminate STGs from blood was greater than for LCTs. An increased LPL activity induced by the higher TG infusion rate may have contributed to the increased metabolic clearance of STGs.

Planar patch clamp: advances in electrophysiology.

PubMed

Brüggemann, Andrea; Farre, Cecilia; Haarmann, Claudia; Haythornthwaite, Ali; Kreir, Mohamed; Stoelzle, Sonja; George, Michael; Fertig, Niels

2008-01-01

Ion channels have gained increased interest as therapeutic targets over recent years, since a growing number of human and animal diseases have been attributed to defects in ion channel function. Potassium channels are the largest and most diverse family of ion channels. Pharmaceutical agents such as Glibenclamide, an inhibitor of K(ATP) channel activity which promotes insulin release, have been successfully sold on the market for many years. So far, only a small group of the known ion channels have been addressed as potential drug targets. The functional testing of drugs on these ion channels has always been the bottleneck in the development of these types of pharmaceutical compounds.New generations of automated patch clamp screening platforms allow a higher throughput for drug testing and widen this bottleneck. Due to their planar chip design not only is a higher throughput achieved, but new applications have also become possible. One of the advantages of planar patch clamp is the possibility of perfusing the intracellular side of the membrane during a patch clamp experiment in the whole-cell configuration. Furthermore, the extracellular membrane remains accessible for compound application during the experiment.Internal perfusion can be used not only for patch clamp experiments with cell membranes, but also for those with artificial lipid bilayers. In this chapter we describe how internal perfusion can be applied to potassium channels expressed in Jurkat cells, and to Gramicidin channels reconstituted in a lipid bilayer.

Dendrimer-assisted patch-clamp sizing of nuclear pores

PubMed Central

Bustamante, J.O.; Michelette, E.R.F.; Geibel, J.P.; Hanover, J.A.; McDonnell, T.J.; Dean, D.A.

2015-01-01

Macromolecular translocation (MMT) across the nuclear envelope (NE) occurs exclusively through the nuclear pore complex (NPC). Therefore, the diameter of the NPC aqueous/electrolytic channel (NPCC) is important for cellular structure and function. The NPCC diameter was previously determined to be ≅10 nm with electron microscopy (EM) using the translocation of colloidal gold particles. Here we present patch-clamp and fluorescence microscopy data from adult cardiomyocyte nuclei that demonstrate the use of patch-clamp for assessing NPCC diameter. Fluorescence microscopy with B-phycoerythrin (BPE, 240 kDa) conjugated to a nuclear localization signal (NLS) demonstrated that these nuclei were competent for NPC-mediated MMT (NPC-MMT). Furthermore, when exposed to an appropriate cell lysate, the nuclei expressed enhanced green fluorescence protein (EGFP) after 5–10 h of incubation with the plasmid for this protein (pEGFP, 3.1 MDa). Nucleus-attached patch-clamp showed that colloidal gold particles were not useful probes; they modified NPCC gating. As a result of this finding, we searched for an inert class of particles that could be used without irreversibly affecting NPCC gating and found that fluorescently labeled Star-burst dendrimers, a distinct class of polymers, were useful. Our patch-clamp and fluorescence microscopy data with calibrated dendrimers indicate that the cardiomyocyte NPCC diameter varies between 8 and 9 nm. These studies open a new direction in the investigation of live, continuous NPC dynamics under physiological conditions. PMID:10784359

Preliminary experimental study on splenic hemodynamics of radiofrequency ablation for the spleen.

PubMed

Baba, Yasutaka; Hayashi, Sadao; Nagasato, Kohei; Higashi, Michiyo; Yoshiura, Takashi

2017-08-01

To test the splenic blood flow change after radiofrequency ablation (RFA) of the spleen in a porcine experimental model. Six pigs underwent RFA of the spleen via laparotomy. During the procedure of RFA, clamping of splenic artery (one) and both splenic artery/vein (one) was also performed. Measurement of blood flow of both splenic artery (SA) and splenic vein (SV) with flow-wire at pre- and post-RFA of the spleen was also performed. Ablated splenic lesions were created as estimating ∼50% area of the spleen in all pigs. Resected specimens reveal not only the coagulated necrosis but also the congestion of the spleen. On the SA hemodynamics, maximum peak velocity (MPV) changed from 37 ± 7 to 24 ± 8 cm/s (normal), 11 to 10 cm/s (clamp of the SA), and 12 to 7.5 cm/s (clamp of both SA/SV), respectively. On the SV hemodynamic, MPV changed from 15 ± 5 to 13 ± 4 cm/s (normal), 17 to 15 cm/s (clamp of the SA), and 17 to 26 cm/s (clamp of both SA/SV), respectively. RFA of the spleen could induce coagulation necrosis and reduce the splenic arterial blood flow.

A laser microsurgical method of cell wall removal allows detection of large-conductance ion channels in the guard cell plasma membrane

NASA Technical Reports Server (NTRS)

Miedema, H.; Henriksen, G. H.; Assmann, S. M.; Evans, M. L. (Principal Investigator)

1999-01-01

Application of patch clamp techniques to higher-plant cells has been subject to the limitation that the requisite contact of the patch electrode with the cell membrane necessitates prior enzymatic removal of the plant cell wall. Because the wall is an integral component of plant cells, and because cell-wall-degrading enzymes can disrupt membrane properties, such enzymatic treatments may alter ion channel behavior. We compared ion channel activity in enzymatically isolated protoplasts of Vicia faba guard cells with that found in membranes exposed by a laser microsurgical technique in which only a tiny portion of the cell wall is removed while the rest of the cell remains intact within its tissue environment. "Laser-assisted" patch clamping reveals a new category of high-conductance (130 to 361 pS) ion channels not previously reported in patch clamp studies on plant plasma membranes. These data indicate that ion channels are present in plant membranes that are not detected by conventional patch clamp techniques involving the production of individual plant protoplasts isolated from their tissue environment by enzymatic digestion of the cell wall. Given the large conductances of the channels revealed by laser-assisted patch clamping, we hypothesize that these channels play a significant role in the regulation of ion content and electrical signalling in guard cells.

Series resistance compensation for whole-cell patch-clamp studies using a membrane state estimator

PubMed Central

Sherman, AJ; Shrier, A; Cooper, E

1999-01-01

Whole-cell patch-clamp techniques are widely used to measure membrane currents from isolated cells. While suitable for a broad range of ionic currents, the series resistance (R(s)) of the recording pipette limits the bandwidth of the whole-cell configuration, making it difficult to measure rapid ionic currents. To increase bandwidth, it is necessary to compensate for R(s). Most methods of R(s) compensation become unstable at high bandwidth, making them hard to use. We describe a novel method of R(s) compensation that overcomes the stability limitations of standard designs. This method uses a state estimator, implemented with analog computation, to compute the membrane potential, V(m), which is then used in a feedback loop to implement a voltage clamp; we refer to this as state estimator R(s) compensation. To demonstrate the utility of this approach, we built an amplifier incorporating state estimator R(s) compensation. In benchtop tests, our amplifier showed significantly higher bandwidths and improved stability when compared with a commercially available amplifier. We demonstrated that state estimator R(s) compensation works well in practice by recording voltage-gated Na(+) currents under voltage-clamp conditions from dissociated neonatal rat sympathetic neurons. We conclude that state estimator R(s) compensation should make it easier to measure large rapid ionic currents with whole-cell patch-clamp techniques. PMID:10545359

A self-strain feedback tuning-fork-shaped ionic polymer metal composite clamping actuator with soft matter elasticity-detecting capability for biomedical applications.

PubMed

Feng, Guo-Hua; Huang, Wei-Lun

2014-12-01

This paper presents a smart tuning-fork-shaped ionic polymer metal composite (IPMC) clamping actuator for biomedical applications. The two fingers of the actuator, which perform the clamping motion, can be electrically controlled through a unique electrode design on the IPMC material. The generated displacement or strain of the fingers can be sensed using an integrated soft strain-gage sensor. The IPMC actuator and associated soft strain gage were fabricated using a micromachining technique. A 13.5×4×2 mm(3) actuator was shaped from Nafion solution and a selectively grown metal electrode formed the active region. The strain gage consisted of patterned copper foil and polyethylene as a substrate. The relationship between the strain gage voltage output and the displacement at the front end of the actuator's fingers was characterized. The equivalent Young's modulus, 13.65 MPa, of the soft-strain-gage-integrated IPMC finger was analyzed. The produced clamping force exhibited a linear increasing rate of 1.07 mN/s, based on a dc driving voltage of 7 V. Using the developed actuator to clamp soft matter and simultaneously acquire its Young's modulus was achieved. This demonstrated the feasibility of the palpation function and the potential use of the actuator in minimally invasive surgery. Copyright © 2014 Elsevier B.V. All rights reserved.

21 CFR 882.4460 - Neurosurgical head holder (skull clamp).

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Neurosurgical head holder (skull clamp). 882.4460 Section 882.4460 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES NEUROLOGICAL DEVICES Neurological Surgical Devices § 882.4460 Neurosurgical head...